Multi-functional material having photo-catalytic function and production method therefor

Multifunctional material with photocatalytic function and manufacturing method thereof

Technical field

The present invention relates to a multifunctional material exhibiting deodorization function, antibacterial function, sterilization function, antifouling function, etc., and a manufacturing method thereof.

Background technique

So far, TiO2, V2O5, ZnO, WO3, etc., have been known as TiO2, V2O5, ZnO, WO3, etc., especially crystalline anatase type, which causes the adsorption or desorption of oxygen molecules by organic compounds such as malodorous components by irradiation with ultraviolet rays. TiO2 particles are highly effective as photocatalysts, so it has been suggested to form a photocatalyst layer on the surface of wall materials, tiles, glass (mirror), circulating filter devices or sanitary ceramics.

The method of forming the above-mentioned photocatalyst layer is known to use CVD method (chemical vapor deposition method), sputtering method, electron beam evaporation method, etc. on the surface of substrates such as plastics, ceramics, and resins to directly form TiO2 particles, etc. Method of forming the photocatalyst layer.

However, when the CVD method, sputtering method, electron beam vapor deposition method, etc. are used, the scale of the equipment is large, the yield is low, and the manufacturing cost is high.

Other methods of forming the photocatalyst layer are also known by kneading photocatalyst particles into a binder and coating them on the surface of the substrate by spraying methods, or by dipping and coating by dip coating, followed by heat treatment. Method (Special Publication No. 5-201747).

However, in order for the photocatalyst particles such as TiO2 particles to exert the photocatalyst effect, it is necessary to irradiate the photocatalyst particles with ultraviolet rays and expose the photocatalyst particles to decomposing substances such as malodorous gas. However, if the photocatalyst particles are mixed as in JP 5-201747 If it is smelted into a binder and then coated on a substrate, many photocatalyst particles are buried in the binder layer and cannot be reached by ultraviolet rays, and cannot be exposed to malodorous gases, so that the catalytic function cannot be fully exerted.

Another known method for forming the photocatalyst layer is the alkoxylate method disclosed in Japanese Patent Publication No. 5-7394. In this method, titanium alkoxide is coated on a glass substrate, dried and then fired at several hundred degrees (Celsius) to form a photocatalyst layer, and the photocatalyst layer is irradiated with ultraviolet rays to decompose organic matter in the water.

The above-mentioned alkoxy compound method can form a thin film at a lower temperature. This is an advantage. As a substrate, hard glass and quartz glass, such as hard glass and quartz glass, which are difficult to soften up to 500°C, can be effectively used as raw materials, but For example, in the case of using a material with a low melting point such as soda lime glass as the substrate, the substrate has begun to soften at the temperature at which the film is formed, and the formed photocatalyst film is embedded in the substrate, so light cannot reach the photocatalyst layer. , Resulting in the so-called undesirable situation where the photocatalytic function cannot be exerted.

In addition, in JP 1-288321, TiO2 sol is sprayed on fibrous material ceramic paper, heat-treated at 400-700°C, then SnO2 sol is sprayed, and heat-treated at 400-700°C to form an improved aldehyde The photocatalyst coating film of oxidative decomposition.

In the method disclosed in JP 1-288321, the entire surface of the coating film is covered with SnO2, which is less active than TiO2. Moreover, when the film strength is increased, cracks are likely to occur. That is, as shown in FIG. 1(a), if a sol containing TiO2 particles 101 is applied to the surface of the tile 100 and heat-treated (sintered), cracks 102 are generated as shown in FIG. 1(b). The reason for this is not only the volume shrinkage (increase in density) caused by the phase transition to rutile type, but also because the interval between TiO2 particles 101 is L0 before sintering as shown in Figure 2(a), but the rutile type is shown in Figure 2 after sintering ( As shown in b), due to the diffusion to the volume of the other party, the interval between the particles is shortened to L1 (L1<L0), so it can be considered that cracks are generated as a result.

On the other hand, Japanese Patent Laid-Open No. 4-46609 discloses a method for purifying odors in the cabin, which is a method of decomposing or modifying the odorous substances contained in the odor of the cabin air to purify the odor in the cabin. It is characterized by irradiating a semiconductor solid photocatalyst made of a metal or metal oxide supported on a semiconductor with light, and at the same time contacting the air in the cabin to be purified with the photocatalyst, thereby decomposing or modifying the photocatalyst through a photochemical reaction. The malodorous substances in the odor in the air.

However, when a substrate coated with a photocatalyst on the surface is used in environments such as sewage and outer walls, it is easy to adhere to pollutants because the atmosphere or water contains macromolecules, dirt, fungi, etc., because it adheres to different types of pollutants. Pollutants, there are cases where the photocatalyst function is reduced.

The previous strategy to deal with the degradation of photocatalyst function caused by the adhesion of pollutants can be found in Special Publication No. 6-7905. Japanese Patent Publication No. 6-7905 discloses a deodorizing device using a photocatalyst. It is composed of a semiconductor photocatalyst layer, an ultraviolet lamp, a heating element, and a hair dryer installed opposite to the photocatalyst layer, and the photocatalyst layer, the heating element, or the photocatalyst layer It moves with the heating element to sequentially heat the entire photocatalyst, and by heating to around 400°C to remove contamination caused by polymers, dust, etc., the photocatalyst layer is regenerated.

However, with this method of photocatalyst regeneration, it is difficult to actually implement the parts used in the equipment installed indoors. Therefore, it is desirable to not remove the pollution after the photocatalyst layer has adhered to it. Of course, the pollution is not easy to adhere. Or solve the problem fundamentally, so that the adhesion of pollution will not reduce the photocatalyst function.

In addition, special publication 6-7906 revealed a method of irradiating a photocatalyst with strong light of ultraviolet intensity to remove bad odors in homes and offices. However, when irradiated with strong light of ultraviolet intensity, the decomposition rate of malodor is different due to the different structure of the photocatalyst. In addition, in the above example, the substrate is porous, and sufficient mechanical strength is obtained by impregnation, etc. However, when the substrate is non-porous materials such as glazed tiles and denser ceramics, sufficient mechanical strength cannot be obtained. strength.

In addition, in TiO2, there are different crystal forms such as anatase, brookite, and rutile. In terms of photoactivity, the anatase type is superior, and the photoactivity of other crystal types is not so good. However, even rutile-type TiO2, such as supporting metals such as Pt and Ag, can increase the photoactivity (Reported in "Surface" magazine 1987, Vol 25), but it is not sufficient in terms of malodor removal rate, compactness and adhesion. Especially when metal Ag and AgO are added, they are not suitable for tiles and building materials because they are black.

In addition, since the titanium oxide sol prepared by the hydrothermal method or the sulfuric acid method is composed of ultrafine particles, it is easy to agglomerate. If the agglomerate is coated on the surface of the substrate, it will cause flare and cracks. Therefore, in order to prevent aggregation, a method of attaching an organic dispersant such as triethanolamine to the surface of the titanium oxide sol has been adopted.

However, when an organic dispersant such as triethanolamine is attached to the surface of the titanium oxide sol, a monodispersed titanium oxide sol is coated on a substrate with low heat resistance such as a resin substrate. If the temperature is less than 300°C Baking and fixing, because the active point organic dispersant of the titanium oxide sol is firmly fixed, and even during the baking process, it is not fully evaporated and decomposed, so the obtained component does not have sufficient photocatalysis, and the deodorization and antibacterial properties are not sufficient. .

In addition, Japanese Patent Laid-Open No. 5-253544 discloses a method of mixing anatase-type titanium oxide into a binder, coating it on the surface of the substrate, and then performing a heat treatment. The method is to form an adhesive layer on the surface of a plate-shaped member constituting the wall, floor or ceiling surface of the living space, and spray the photocatalyst mainly composed of anatase titanium oxide on the surface of the adhesive layer Fine powder, and part of it is exposed from the adhesive layer, so that it adheres to the surface of the adhesive layer, and then heated in the range of 300°C or more and 900°C or less to melt the adhesive layer, and then cool to The adhesive is cured.

In this method, if the heat treatment is performed at 300°C or higher and 900°C or lower, the deodorization performance is good, but good deodorization performance cannot be obtained at a low temperature of 200°C or lower. Therefore, it is difficult to add a good photocatalyst such as excellent deodorization properties to substrates such as heat-labile plastics. The reason can be considered to be that in order to uniformly coat the photocatalyst particles on the substrate, it is necessary to monodisperse the photocatalyst fine particles in the suspension first. For this reason, an organic dispersant is added, which does not decompose sufficiently below 300°C , Vaporization, and remaining to cover the active part of the photocatalyst particles.

Therefore, the object of the present invention is to provide a multifunctional material capable of fully exerting the photocatalytic effect in a manner that the photocatalyst layer is exposed from the substrate, and using the substrate to hold the photocatalyst layer particularly well.

In addition, the purpose of the present invention is to form a photocatalyst layer that is not easily peeled off on a relatively dense substrate such as glass, ceramic tile, metal, and plastic.

In addition, the object of the present invention is to form a photocatalyst layer on a low-melting-point substrate, such as a soda lime glass that is relatively inexpensive and easy to process.

In addition, the object of the present invention is to provide such a multifunctional material that is not easy to adhere to contaminants, can prevent functional degradation caused by contaminants, has antibacterial or deodorant properties, and has excellent mechanical strength.

In addition, the object of the present invention is to provide a multifunctional material having excellent peel strength even with a photocatalyst layer mainly composed of anatase TiO2.

In addition, the object of the present invention is to improve the photocatalytic activity of a photocatalyst layer mainly composed of rutile TiO2.

Furthermore, the purpose of the present invention is to support Ag on a photocatalyst layer mainly composed of rutile TiO2 to improve the photocatalytic activity, and at the same time decolor the photocatalyst layer and make the appearance better.

In addition, the object of the present invention is to provide a multifunctional material having a good photocatalytic function even if it is subjected to a low temperature heat treatment of 300°C or less.

Disclosure of the Invention The multifunctional material of the present invention is a material obtained by forming a photocatalyst layer directly or through an adhesive layer on the surface of ceramics, resins, metals, woods, such as ceramic tiles, sanitary ceramics, glass, etc. The type and particle size of the photocatalyst particles in the photocatalyst layer, the gaps formed between the photocatalyst particles, the porosity, the relationship between the binder layer and the photocatalyst layer, the particles that fill the gaps between the photocatalyst particles, especially fixed on the photocatalyst particles There are no special requirements for metal particles and the like on the surface. With these, a multifunctional material with excellent photocatalytic effect as a photocatalyst layer for deodorization, etc., as well as excellent antibacterial properties and abrasion resistance is made.

Brief Description of the Drawings Fig. 1 (a) is a diagram showing the state of a conventional TiO2 sol before sintering, and (b) is a diagram showing the state after sintering of the rutile type.

Fig. 2 (a) is a diagram showing the state of the conventional TiO2 particles before sintering, and (b) is a diagram showing the state after sintering.

3 is a diagram showing a state in which the photocatalyst particles constituting the photocatalyst layer are combined with each other by potential energy in the multifunctional material with photocatalytic function of the present invention.

Fig. 4 is a diagram schematically showing a state where the photocatalyst particles constituting the photocatalyst layer are solid-phase sintered and bonded to each other in the same multifunctional material.

Fig. 5 is a diagram schematically showing a state in which small particles are filled in gaps formed between photocatalyst particles constituting the photocatalyst layer in the same multifunctional material.

Fig. 6 is a diagram schematically showing a state in which metal particles are immobilized on the surface of the photocatalyst particles of the multifunctional material shown in Fig. 3.

Fig. 7 is a diagram schematically showing a state in which metal particles are immobilized on the surface of the photocatalyst particles of the multifunctional material shown in Fig. 4.

Fig. 8 is a diagram schematically showing a state in which metal particles are immobilized on the surface of the photocatalyst particles of the multifunctional material shown in Fig. 5.

FIG. 9 is a diagram schematically showing a state in which the photocatalyst layer is bonded to the base material through the adhesive layer in the same multifunctional material, and the photocatalyst particles constituting the photocatalyst layer are bonded with each other by potential energy.

FIG. 10 is a diagram schematically showing a state in which the photocatalyst layer is bonded to the substrate through the adhesive layer in the same multifunctional material, and the photocatalyst particles constituting the photocatalyst layer are bonded to each other by solid phase sintering.

FIG. 11 is a diagram schematically showing a state in which the photocatalyst layers are joined by the adhesive layer in the same multifunctional material, and the gaps formed between the photocatalyst particles are filled with small particles.

Fig. 12 is a diagram schematically showing a state in which metal particles are immobilized on the surface of the photocatalyst particles of the multifunctional material shown in Fig. 9.

Fig. 13 is a diagram schematically showing a state in which metal particles are immobilized on the surface of the photocatalyst particles of the multifunctional material shown in Fig. 10.

Fig. 14 is a diagram schematically showing a state in which metal particles are immobilized on the surface of the photocatalyst particles of the multifunctional material shown in Fig. 11.

Fig. 15 is a diagram illustrating a method of manufacturing the multifunctional material with photocatalytic function of the present invention.

Figure 16 (a) and (b) are enlarged views of TiO2 particles.

Figures 17(a)-(c) are diagrams illustrating the sintering mechanism of TiO2 particles.

Fig. 18 shows a graph regarding the results of the antibacterial property test.

Fig. 19 shows a comparison curve of the test results of Cu loading when entering the drying process and not entering the drying process before the BLB lamp is irradiated.

Fig. 20 shows the relationship between the Cu loading amount and the Cu coating amount.

Fig. 21 is a manufacturing process diagram showing another embodiment.

Fig. 22 shows the test result curve of the antibacterial property test.

Fig. 23 shows a comparison curve of the test results of Cu loading when entering the drying process and not entering the drying process before the BLB lamp is irradiated.

Fig. 24 shows the relationship between the Cu supported amount and the Cu coating amount.

Figure 25 shows the relationship between the Ag loading and the survival rate of the bacteria.

Fig. 26 is a conceptual diagram of the basic distribution when observing the cross-sectional direction of the multifunctional material with EPMA (Electron Beam Microanalyzer).

Fig. 27 is a conceptual diagram of the basic distribution when observing the cross-sectional direction of the multifunctional material with EPMA (Electron Beam Microanalyzer). Fig. 28 is a graph showing the relationship between the combination of TiO2 and SnO2 and the film strength and smoothness.

Figure 29 shows the relationship between heat treatment temperature and finish.

Fig. 30 is a diagram illustrating a method for measuring the activity of a photocatalyst thin film.

Fig. 31 is a diagram illustrating a method of measuring the activity of a photocatalyst thin film.

Fig. 32 is a diagram illustrating a method of measuring the activity of the photocatalyst thin film.

Figure 33 shows the relationship between the UV irradiation time and the pH change.

Fig. 34 shows the relationship between R30 and the amount of change in pH.

Fig. 35 shows the relationship between porosity and deodorization (R30) and abrasion resistance.

Fig. 36 shows the relationship between film thickness and deodorization (R30).

Fig. 37 shows the relationship between film thickness and deodorization (R30) and peeling resistance.

Fig. 38 shows the relationship between the addition amount of SnO2 and the deodorant properties (R30) and abrasion resistance.

Figure 39 shows the relationship between the amount of SnO2 added and the difficulty of contamination adhesion.

Fig. 40 shows the relationship between the amount of SnO2 added and the open porosity on the surface of the TiO2 layer.

Figure 41 shows the relationship between the amount of SnO2 added and the width of open pores on the surface of the TiO2 layer.

Fig. 42 shows the relationship between the amount of SnO2 added, the deodorant R30 (L), and the peeling resistance.

Fig. 43 shows the relationship between porosity, deodorant R30 (L), and abrasion resistance.

Fig. 44 shows the relationship between the number of coatings and the difficulty of adhesion of contamination.

Figure 45 shows the relationship between the number of coatings and abrasion resistance.

Figure 46 shows the relationship between the number of coatings and the open porosity on the surface of the TiO2 layer.

Fig. 47 is a diagram showing a state in which ultraviolet rays are irradiated to preferentially decompose and vaporize the thermosetting resin on the photocatalyst particles, and the photocatalyst particles are exposed to the air.

Fig. 48 is the same diagram as Fig. 47 showing another embodiment.

Fig. 49 is the same diagram as Fig. 47 showing another embodiment.

Fig. 50 is a diagram showing a state in which small particles are filled in the gaps of the photocatalyst particles.

Fig. 51 is a block diagram showing a manufacturing process of a multifunctional material using rutile TiO2.

FIG. 52 shows the relationship between the concentration of the Cu solution and the photoactivity when the Cu solution is dried for photoreduction.

Fig. 53 shows the relationship between the concentration of the Cu solution and the photoactivity when the Cu solution is not dried for photoreduction.

Fig. 54 shows the relationship between the concentration of the Cu solution and the malodor removal rate R30 when Cu is used as the supporting metal on the rutile TiO2 thin film (the reduction of metal ions is performed after the metal salt aqueous solution is dried).

Fig. 55 shows the relationship between the concentration of the Cu solution and the odor removal rate R30 when the wall tiles are used as the base and Cu is the metal supported on the rutile TiO2 film (the reduction of metal ions is performed after the metal salt solution is dried).

Fig. 56 is a graph showing the relationship between the firing temperature for forming the rutile TiO2 thin film and the odor removal rate R30 after Cu immobilization.

Fig. 57 shows the relationship between the solution concentration of Ag and Cu and the color difference.

Figure 58 shows the relationship between porosity, R30 and wear resistance.

Fig. 59 shows the relationship between the amount of copper supported and the survival rate of bacteria.

Fig. 60 shows the relationship between the coating amount of copper and the supporting amount of copper.

Fig. 61 is a graph showing the relationship between the amount of silver carried and the survival rate of bacteria.

Fig. 62 is a graph showing the relationship between the amount of silver supported and the chromatic aberration.

Fig. 63 shows the effect curve of the decolorization treatment with the KI aqueous solution.

Fig. 64 is a graph showing the relationship between the change in pH of the KI aqueous solution and the change in the offensive odor removal rate R30 before and after the decolorization treatment with the KI aqueous solution.

Figure 65 is a graph comparing antibacterial effects.

Fig. 66 is a graph showing abrasion resistance with respect to the weight ratio of tin oxide in the film.

Fig. 67 is a graph showing the photoactivity relative to the weight ratio of tin oxide in the thin film.

FIG. 68 is a graph showing abrasion resistance with respect to the weight ratio of tin oxide in a thin film as a comparative example.

Fig. 69 is a graph showing the photoactivity relative to the weight ratio of tin oxide in the thin film as a comparative example.

Fig. 70 is a graph showing the relationship between the amount of silver supported and the survival rate of bacteria.

Best Mode for Carrying Out the Invention In order to describe the present invention in more detail, the present invention will be explained in accordance with the accompanying drawings.

Figures 3 to 14 divide the structure of the multifunctional material with photocatalytic function of the present invention into various types, and the multifunctional material with photocatalytic function of the present invention belongs to one of the structures.

In the multifunctional material shown in FIG. 3, a photocatalyst layer 2 with a photocatalytic function is directly provided on the surface of a substrate 1. The photocatalyst layer 2 is composed of fine photocatalyst particles 3 with surface energy and curved surface energy between each other. It is composed of a combination of potential energy.

In the multifunctional material shown in FIG. 4, a photocatalyst layer 2 having a photocatalytic function is directly provided on the surface of a substrate 1, and the photocatalyst layer 2 is formed by solid-phase sintering of photocatalyst particles 3.

In the multifunctional material shown in FIG. 5, a photocatalyst layer 2 having a photocatalytic function is directly provided on the surface of a substrate 1, and the gaps formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 are filled more than this The particles 4 with smaller gaps are formed by combining the photocatalyst particles 3 with each other by such small particles 4.

In addition, in the figure, the structure in which the particles 4 are filled in the internal gaps is shown, but the particles 4 may be filled at least in the gaps of the surface layer photocatalyst particles 3. That is, in terms of the mechanical strength of the photocatalyst layer, in order to attenuate the transmission of external force internally, it is considered that surface bonding is important. Therefore, only fine particles may be filled in the gaps between the photocatalyst particles on the surface layer. However, at this time, the internal photocatalyst particles are combined by potential energy. In order to obtain sufficient photocatalyst layer strength, the average particle diameter of the photocatalyst particles is preferably 0.04 μm.

In the multifunctional material shown in FIG. 6, the photocatalyst particles 3 forming the photocatalyst layer 2 directly on the surface of the substrate 1 are combined with each other with potential energy, and Ag is also fixed on the surface of the photocatalyst particle 3 , Cu and Cu2O and other electron trapping particles5.

In the multifunctional material shown in FIG. 7, the photocatalyst particles 3 constituting the photocatalyst layer 2 directly formed on the surface of the substrate 1 are bonded to each other by a solid phase sintering phase, and Ag is also fixed on the surface of the photocatalyst particles 3 And metal particles such as Pt5.

In the multifunctional material shown in FIG. 8, a photocatalyst layer 2 having a photocatalytic function is directly provided on the surface of a substrate 1, and the gaps formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 are filled more than The particles 4 with small gaps, through the small particles 4, the photocatalyst particles 3 are combined with each other, and metal particles 5 such as Ag and Pt are also fixed on the surface of the photocatalyst particles 3.

In the multifunctional material shown in FIG. 9, a photocatalyst layer 2 having a photocatalytic function is provided on the surface of a substrate 1 through an adhesive layer 6. The photocatalyst layer 2 is exposed to the outside while the lower layer is buried. Into the adhesive layer 6, and the fine photocatalyst particles 3 on the surface layer are combined with each other by potential energy.

In the multifunctional material shown in FIG. 10, the photocatalyst layer 2 is also provided by the adhesive layer 6, and on the surface of the photocatalyst layer 2, the photocatalyst particles 3 are combined with each other by a solid phase sintering phase.

In the multifunctional material shown in FIG. 11, the photocatalyst layer 2 is provided on the base material 1 through the adhesive layer 6, and the gap formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 is filled more than the gap The small particles 4 are combined with each other through the photocatalyst particles 3.

In the multifunctional material shown in FIG. 12, the photocatalyst layer 2 is formed on the surface of the base material 1 through the adhesive layer 6, and the photocatalyst particles 3 constituting the photocatalyst layer 2 are bonded to each other by potential energy. Electron trap particles 5 such as Ag, Cu and Cu2O are also fixed on the surface of the photocatalyst particles 3.

In the multifunctional material shown in FIG. 13, a photocatalyst layer 2 is formed on the surface of a base material 1 through a binder layer 6, and the photocatalyst particles 3 constituting the photocatalyst layer 2 are bonded to each other by a solid phase sintering phase. On the surface of the photocatalyst particles 3, electron trap particles 5 such as Ag, Cu, and Cu2O are also fixed.

In the multifunctional material shown in FIG. 14, the photocatalyst layer 2 is provided on the base material 1 through the adhesive layer 6, and the gap formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 is filled smaller than the gap. Through the small particles 4, the photocatalyst particles 3 are combined with each other, and metal particles 5 such as Ag and Pt are also fixed on the surface of the photocatalyst particles 3.

Among the above multifunctional materials, as the substrate 1, ceramics such as ceramic tiles, sanitary ceramics, glass, resins, metals, wood, or composites thereof may be used.

In addition, the so-called photocatalyst particles 3 are semiconductor particles having a very large band gap in order to exert photocatalytic functions such as antibacterial function and deodorizing function. As the reason why the photocatalyst particles have antibacterial properties, although there is a saying that they are electrocuted by applying a voltage higher than a predetermined value, it is generally considered that, like the deodorization function, it is the cause of the generation of active oxygen when light is irradiated. In order to generate active oxygen, one of the conduction bands of the semiconductor is required to be above the hydrogen generation potential when represented by an energy band model, and the upper end of the valence electron band must be below the oxygen generation potential. Among the semiconductors that satisfy this condition, there are TiO2, SrTiO3, ZnO, SiC, potassium phosphide, CdS, CdSe, MoS3, and the like. In addition, if the particles are refined, the position of the conduction band moves upward. Therefore, if fine particles of about 1-10 nm are formed, SnO2, WO3, FeO3, Bi2O3, etc. may all generate active oxygen. Among them, anatase-type TiO2 is particularly preferred because it is chemically stable and can obtain fine particles with high activity at a low cost.

In addition, the so-called electron trap particles refer to particles that trap electrons and prevent recombination of electrons and holes when light is irradiated on the photocatalyst to generate electrons and holes. Specific examples include Ag, Cu, Pt, and Pd. , Ni, Co, Fe, Cu2O, etc.

In addition, the adhesive layer 6 is made of a thermoplastic material such as glaze, inorganic glass, thermoplastic resin, and solder. In this way, the adhesive layer is composed of a thermoplastic material, and the photocatalyst can be coated on the adhesive layer at room temperature by a simple and inexpensive method such as spraying, and only heat treatment is required to make the substrate 1, the adhesive The layer 6 and the photocatalyst layer 2 are firmly bonded, which is advantageous in terms of manufacturing cost.

In addition, the multifunctional material with photocatalytic function of the present invention is formed by laminating a photocatalyst layer composed of photocatalyst particles on a sheet-shaped adhesive layer composed of a thermoplastic material or embedding a part of the photocatalyst layer in the adhesive layer. After attaching such a sheet-like multifunctional material to original tiles, sanitary ceramics, building materials, etc., if heated, functions such as deodorization, antifouling, antibacterial, and mildew resistance can be added to the original tiles.

Since the specific surface area becomes larger and the photocatalytic activity is improved, the average particle diameter of the photocatalyst particles 3 constituting the photocatalyst layer 2 is preferably 0.3 μm or less.

The thickness of the photocatalyst layer 2 is preferably 0.1 μm to 0.9 μm. Below 0.1 μm, the photocatalyst particles are partially embedded in the adhesive layer 6 and a part that cannot exhibit catalytic activity is formed on the surface of the multifunctional material. As a result, bacteria accumulate on the part, so the antibacterial property is particularly deteriorated. If it exceeds 0.9 μm, the thickness variation will increase, and the contamination will not easily fall off when the contamination adheres to the sample. The thickness of the photocatalyst layer here includes from the outermost surface of the photocatalyst film to the part buried in the underglaze layer. Specifically, elemental analysis such as EPMA (electron beam microanalyzer) is performed to form the main component elements of the glaze layer. The value is increased, and the distance from the uppermost part to the outermost surface of the part where the value is approximately constant is calculated and measured.

In addition, a method of changing the thickness of the photocatalyst layer 2 can also obtain a special effect. That is, if the thickness is 0.2 μm or more and 0.4 μm or less, the light interference effect in the thickness direction of the photocatalyst layer can be used to add an iridescent pattern. In addition, if you want to form only the base color of the base material, the pattern or these in appearance In addition to the above-mentioned light interference effect, the photocatalyst layer film thickness may be 0.1 μm or more, 0.2 μm or less, or 0.4 μm or more and 1 μm or less. Such a method can be used in a wide range of tiles, sinks, bathtubs, toilets, sinks, kitchen tables, etc.

In the case where only the photocatalyst particles 3 are bonded to each other, only the potential energy (adsorption) or sintering between the photocatalyst particles is used. However, when using the mutual sintering effect of the photocatalyst particles, the sintering must be carried out at a relatively high temperature. On the other hand, in the case of using adsorption, if the specific surface area of the photocatalyst particles is not made quite large, and if the filling performance is not made good , The bonding is not enough, only the active point adsorption part of the photocatalyst particles is consumed, and the production of multifunctional materials with sufficient catalytic activity and abrasion resistance is limited in terms of methods.

In addition, in order to strengthen the bonding of the photocatalyst particles 3, if particles larger than the gaps between the photocatalyst particles 3 are used, not only sufficient bonding force will not be obtained, but also the photocatalyst particles exposed on the surface of the multifunctional material will be partially covered. There are parts on the surface of the multifunctional material that cannot exhibit catalytic activity, and bacteria are retained on this part, so the antibacterial properties are significantly deteriorated.

In addition, the gap between the photocatalyst particles mentioned here refers to the necked part between the photocatalyst particles 3 and 3 as shown in FIG. 16(a), and as shown in FIG. 16(b), the photocatalyst particles 3, 3 pores between. Therefore, the small particles 4 having a particle size smaller than the gap between the photocatalyst particles refer to particles having a smaller gap than either the necked portion between the photocatalyst particles and the pores between the photocatalyst particles. There is a particularly effective method for bonding the photocatalyst particles to each other as shown in Fig. 16(b).

The small particles 4 filled in the gaps of the photocatalyst particles 3 are basically not limited in material, but may be materials with good adsorption power. The use of materials with extremely weak adsorption capacity cannot achieve the purpose of combining the photocatalyst particles with each other. In addition, when a material with a strong adsorption capacity is used to cover the active points on the surface of the photocatalyst particle instead of being inserted into the gap, the probability increases . From this point of view, as the material of the particles filled in the gaps of the photocatalyst particles, metals or oxides such as Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni, etc., are ideally used as carriers. The zeolite, activated carbon, clay, etc. are not ideal. Among the above-mentioned metals or oxides, tin oxide is desirable in terms of having a moderate adsorption capacity, and metals or oxides such as Ag and Cu not only bind the photocatalyst particles to each other, but also have antibacterial properties by themselves. It is deodorant, so it is ideal for applications that utilize this function, especially in the function of assisting photocatalysis when there is no light irradiation. That is, as the small particles 4 filled in the gaps of the photocatalyst particles 3, the above-mentioned metal particles 5 can be used.

Furthermore, the average particle diameter of the particles 4 filled in the gaps of the photocatalyst particles 3 is preferably 4/5 or less of the average particle diameter of the photocatalyst particles 3.

The particles 4 filling the gaps of the photocatalyst particles 3 are not only attached to the gaps between the photocatalyst particles, but also to the photocatalyst particles by the current manufacturing method. Moreover, if the particle size of the particles filling the gap exceeds 4/5 of the average particle size of the photocatalyst particles, the probability of attaching to the surface of the photocatalyst particles is higher than the probability of filling the gaps of the photocatalyst particles. Therefore, the photocatalyst particles 3 are separated from each other. The bonding strength is reduced. If the particles filling the gap are larger than the photocatalyst particles, it is equivalent to partially covering the photocatalyst particles, and a part that cannot exhibit catalytic activity is formed on the surface of the multifunctional material. Since bacteria are retained on this part, there is particularly significant antibacterial activity. The possibility of deterioration.

In addition, the average particle diameter of the particles 4 filled in the gaps of the photocatalyst particles 3 is preferably 0.01 μm or less, so that the specific surface area is increased and a moderate adsorption force can be obtained.

Furthermore, the particles 4 filled in the gaps of the photocatalyst particles 3 are preferably 10% or more and 60% or less in molar ratio with respect to the total amount of the photocatalyst particles 3 and the filling particles 4. When the photocatalyst layer is fixed to the substrate through the adhesive layer by heat treatment in a temperature region where sintering of the photocatalyst particles does not occur, if the amount of particles filling the gap is too small, the photocatalyst particles cannot be firmly connected to each other. Combination, on the other hand, if the amount of particles filling the gap is too large, the amount of particles covering the photocatalyst particles will increase, and a part that cannot exhibit catalytic activity is formed on the surface of the multifunctional material. Bacteria are retained on this part. In particular, the antibacterial properties are remarkably deteriorated, so the above-mentioned range is ideal.

In addition, as the material constituting the particles 4 filled in the gaps of the photocatalyst particles 3, a material having a vapor pressure higher than that of the material constituting the photocatalyst particles is selected, and it is desirable to make the particles filled in the gaps of the photocatalyst particles Condensed in the necked part between the photocatalyst particles. In this way, a stronger bond between the photocatalyst particles can be achieved. In order to increase the peel strength of the photocatalyst layer, not only the filling method but also the sintering method can be used. In addition, if the particles 4 for filling the gap are selected from such a material with high vapor pressure, the sintering temperature can be lowered even when used as a sintering aid.

Such substances with high vapor pressure include tin oxide, bismuth oxide, zinc oxide, etc., but tin oxide is best for safety reasons.

In addition, the thickness of the layer including the particles 4 filled in the gaps of the photocatalyst particles 3 is preferably 0.1 μm or more. The thickness of this layer is less than 0.1 μm, and the photocatalyst particles (and particles that fill the gaps by the manufacturing method) are partially embedded in the adhesive layer 6, forming a part that cannot exhibit catalytic activity on the surface of the multifunctional material. It can retain bacteria, so especially the antibacterial property is significantly deteriorated. Here, the thickness of the layer including the particles 4 filled in the gaps of the photocatalyst particles includes the thickness from the outermost surface to the lower layer portion where the adhesive layer is embedded, and the average thickness of the respective convexities and concaves.

FIG. 15 illustrates an example of the manufacturing method of the multifunctional material with photocatalytic function of the present invention. In the present invention, first, as shown in FIG. 15(a), the substrate 1 is prepared, as shown in the figure (b), An adhesive layer 6 is formed on the surface of the base material 1. For the adhesive layer 6, a material having a softening temperature lower than that of the base material 1 is selected. To give an example, when the substrate 1 is a ceramic tile, hollow glass frit, or ceramics, a glaze layer or a printing layer can be used as the adhesive layer 6 as it is.

Next, as shown in (c) of the figure, a photocatalyst layer 2 composed of photocatalyst particles such as TiO2 particles is formed on the adhesive layer 6. At this time, the photocatalyst layer 2 is maintained with a bonding force that does not fall off from the adhesive layer 6 during subsequent firing, and may be supported on the adhesive layer 6.

Alternatively, before forming the adhesive layer 6 on the surface of the substrate 1, as shown in the figure (b), the photocatalyst layer 2 may be formed in advance on the adhesive layer 6, and the adhesive layer 6 Placed on the base material 1.

After that, heating treatment is performed at an atmosphere temperature higher than the softening temperature of the adhesive layer 6 and lower than the softening temperature of the base material 1 in the range of more than 20°C and below 320°C, as shown in Figure (d) or Figure 9 As shown in FIG. 14, in the photocatalyst layer 2, a part of the lower layer on the adhesive layer side is deposited on the molten adhesive layer. Because the adhesive layer is solidified, this part is buried in the adhesive layer. Is held firmly. In addition, in the photocatalyst layer 2, the photocatalyst particles 3 constituting the surface layer in contact with the external atmosphere utilize mutual potential energy, intermolecular force, and sintering caused by firing. As shown in FIG. 16(a), a part of the phase Combine and separate the other parts as shown in Figure 16(b). That is, the surface of the photocatalyst particles in the surface layer is substantially exposed to the outside.

Here, the heat treatment temperature is increased to a range higher than the softening temperature of the adhesive layer 6 by more than 20°C and 320°C or less. If it is less than 20°C, the softening of the adhesive takes time and the light cannot be sufficiently completed. The retention of the catalyst particles 3a, on the other hand, if the temperature exceeds 320°C, the adhesive layer rapidly melts and the photocatalyst particles are embedded in the adhesive layer, resulting in uneven surfaces, fragments and pores. Therefore, 40 Above °C, below 300°C.

Furthermore, assuming that the specific gravity of the photocatalyst particles 3 is δt and the specific gravity of the adhesive layer 6 is δb, a relationship of 0δt-δb3.0, preferably 0.5δt-δb2.0 is formed. If the specific gravity difference between the photocatalyst particles and the adhesive layer is too small, when the adhesive layer is melted, the moving speed of the photocatalyst particles in the vertical direction in the adhesive layer will slow down, and the photocatalyst particles will easily peel off after calcination If the specific gravity difference between the photocatalyst particles and the binder layer is too large, the moving speed of the photocatalyst particles in the vertical direction will increase, and most of the photocatalyst particles will be buried in the binder layer. This phenomenon keeps bacteria on it and reduces the antibacterial properties.

Furthermore, as an application of this method, even when δt-δb>3.0 is necessary, the second adhesive layer with 0δt-δb3.0 can be interposed between the adhesive layer and the photocatalyst particles. between.

In addition, when δt-δb<0, applying pressure during the heat treatment has the same effect as increasing the specific gravity difference δt-δb. Therefore, by the HIP treatment, the hot pressing treatment can obtain the same effect as when 0δt-δb3.0.

In addition, the gaps of the photocatalyst particles constituting the exposed part of the adhesive layer 6 are specifically shown in FIG. 16(a), the necked part of the photocatalyst particles 3b, or the photocatalyst particles as shown in FIG. 16(b). 3, in order to bond the photocatalyst particles to each other, particles with a particle size smaller than the gap can be filled 4 (Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni and other metals or oxides, etc.) ).

In addition, as another manufacturing method of the multifunctional material with photocatalytic function of the present invention, it is also possible to form an adhesive layer 6 composed of a thermoplastic material on a substrate 1 such as ceramics, resins, or metals, and then, on the adhesive The layer 6 is coated with a mixture of photocatalyst particles 3 and particles 4 with small particle diameters in a sol or precursor state to form the photocatalyst layer 2. After that, the adhesive layer 6 is softened to make the photocatalyst layer 2 A part of the lower layer is buried in the adhesive layer 6, and then cured.

According to this method, it is not only simple, but also because it is coated in a sol or precursor state and mixed with a mixture of particles 4 and photocatalyst particles 3 that are pre-filled in the gap to form a photocatalyst layer. The mixing ratio of the particles 4 is very convenient.

In addition, as another manufacturing method of the multifunctional material with photocatalytic function of the present invention, the sheet-shaped adhesive layer 6 composed of a thermoplastic material may be coated with photocatalyst particles 3 and mixed in a sol or precursor state. A mixture of particles 4 with small particle diameters forms the photocatalyst layer 2. The sheet-like adhesive layer 6 forming the photocatalyst layer 2 is carried or pasted on a substrate such as ceramic, resin, or metal, and then the above-mentioned adhesive The agent layer is softened, and a part of the lower layer of the photocatalyst layer is embedded in the adhesive, and then cured.

Furthermore, as another method of manufacturing the multifunctional material with catalytic function of the present invention, an adhesive layer 6 composed of a thermoplastic material may be formed on a substrate 1 such as ceramics, resins, or metals, and then the adhesive layer 6 A photocatalyst layer 2 composed of photocatalyst particles 3 is formed on the layer 6. After that, the adhesive layer 6 is softened, a part of the lower layer of the photocatalyst layer 2 is buried in the adhesive layer, and then the adhesive layer is cured Then, the solution containing the small particle size particles is coated on the photocatalyst layer, and the small particle size particles 4 are fixed on the photocatalyst particles by heat treatment.

This method is easy to implement when the particles that fill the gaps are oxides, and when a porous photocatalyst layer is produced, a large number of particles that fill the gaps can be attached.

Also, as another method of manufacturing the multifunctional material with photocatalytic function of the present invention, a photocatalyst layer 2 composed of photocatalyst particles 3 may be formed on a sheet-like adhesive layer 6 composed of a thermoplastic material, and then The sheet-like adhesive layer forming the photocatalyst layer is placed or pasted on a substrate 1 such as ceramic, resin, or metal. After that, the adhesive layer 6 is softened and a part of the lower layer of the photocatalyst layer 2 is buried in the adhesive. In the binder layer 6, the adhesive layer is then cured, and then a solution containing metal particles 4 is coated on the photocatalyst layer, and the above-mentioned small particle size particles are fixed on the photocatalyst particles 3 by heat treatment.

In addition, as another method of manufacturing the multifunctional material with photocatalytic function of the present invention, an adhesive layer 6 composed of a thermoplastic material may be formed on a substrate 1 such as ceramics, resins, or metals, and then the adhesive layer 6 A photocatalyst layer 2 composed of photocatalyst particles 3 is formed on the layer 6. After that, the above-mentioned adhesive layer is softened, a part of the lower layer of the photocatalyst layer is buried in the adhesive layer, and then the adhesive layer is cured, and then the adhesive layer is cured. The photocatalyst layer is coated with a solution containing ions of the small metal particles 4, and then irradiated with light containing ultraviolet rays to reduce the metal ions and fix them on the photocatalyst particles.

This method is simple to implement when the particles in the filling gap are metal, and the metal can be fixed in a very short time (several minutes). In addition, the lamp used for ultraviolet irradiation may be any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, and a fluorescent lamp.

Furthermore, as another manufacturing method of the multifunctional material with photocatalytic function of the present invention, a photocatalyst layer composed of photocatalyst particles can also be formed on a sheet-shaped adhesive layer composed of a thermoplastic material, and then a photocatalyst layer is formed. The flaky adhesive layer 6 of the catalyst layer is placed or pasted on a substrate 1 such as ceramic, resin, or metal. After that, the adhesive layer 6 is softened, and a part of the lower layer of the photocatalyst layer is buried in the adhesive layer. In 6, the adhesive layer 6 is then cured, and then a solution containing the ions of the small particle size metal particles 4 is coated on the photocatalyst layer 2, and then light containing ultraviolet rays is irradiated to reduce the metal ions and fix them on the photocatalyst particles. on.

In addition, as another method of manufacturing the multifunctional material with photocatalytic function of the present invention, it is also possible to form an adhesive layer 6 composed of a thermoplastic material on a substrate 1 such as ceramics, resins, or metals, and then bond the adhesive layer 6 A photocatalyst layer 2 composed of photocatalyst particles 3 is formed on the agent layer 6, a solution containing the ions of the small particle size metal particles 4 is coated on the photocatalyst layer 2, and then light containing ultraviolet rays is irradiated to reduce the metal ions It is fixed on the photocatalyst particles 3, and then the adhesive layer 6 is softened, so that a part of the lower layer of the photocatalyst layer is buried in the adhesive layer, and then the adhesive layer is cured.

According to this method, because the heat treatment process can be completed at one time, the productivity can be improved.

Furthermore, as another method of manufacturing the multifunctional material with photocatalytic function of the present invention, a photocatalyst layer 2 composed of photocatalyst particles 3 may also be formed on a sheet-like adhesive layer 6 composed of a thermoplastic material. The photocatalyst layer 2 is coated with a solution containing ions of small-diameter metal particles 4, and then irradiated with light containing ultraviolet rays to reduce the metal ions to be fixed on the photocatalyst particles 3, and then the flakes forming the photocatalyst layer 2 The adhesive layer is placed or pasted on a substrate 1 such as ceramics, resins, or metals. After that, the adhesive layer 6 is softened, and a part of the lower layer of the photocatalyst layer 2 is embedded in the adhesive layer, and then cured Adhesive layer.

Here, ZnO may be used as the photocatalyst particles, and Ag or Ag2O may be used as the metal particles 4 filled in the gaps of the photocatalyst particles. Ag or Ag2O particles not only strengthen the binding of the photocatalyst ZnO particles to each other, but also enhance the photocatalytic effect of ZnO, and it also has antibacterial and deodorant effects. In addition, because ZnO is selected as the photocatalyst, the coloration caused by Ag ions can be eliminated, and unexpected effects can be obtained by using the background color, pattern, or combination of the substrate.

In addition, between the metal ions filling the gaps of the photocatalyst particles, a solution containing a salt that forms an insoluble colorless or white salt may be brought into contact with the photocatalyst layer, and then light containing ultraviolet rays may be irradiated.

In this way, even if ZnO and Ag or Ag2O are not combined, the coloring caused by the particles that fill the gap can be eliminated, and the base color, pattern, or their combination can be used to improve unexpected effects.

In addition, TiO 2 is used as the photocatalyst particles, and 800° C. or more and 1000 or less may be used as the heat treatment temperature for softening the adhesive layer 6. When the temperature is above 800°C, the TiO2 particles are formed between the TiO2 particles due to the formation of the initial sintering necking. Therefore, although the bonding strength between the TiO2 particles is increased, if the temperature exceeds 1000°C, the middle-term sintering process will move to the solidification of TiO2. Due to phase sintering, the volume of the photocatalyst layer shrinks significantly, so cracks are likely to occur.

In addition, TiO2 is used as the photocatalyst particles, Ag is used as the particles 4 filled in the gaps of the photocatalyst particles, and aqueous solutions of halides such as KI, KCl, FCl3, etc. A salt solution of colored or white salt. Ag forms insoluble colorless or white salts such as AgI and AgCl between Ag and halogenated alkali, so it is expected to improve the effect of using the base color, pattern, or their combination of the base material.

In addition, when a dispersion process is provided as the previous process of the process of coating photocatalyst particles on the binder layer, it is used to disperse the sol or precursor that should become the photocatalyst particles in the dispersant of the dispersion process in the solution. It is preferable to use only a component that vaporizes at a temperature lower than the heat treatment temperature of the softening adhesive layer.

In the prior art, there is no deodorization at a temperature of less than 320°C. This is because the dispersant attached to the surface of the TiO2 particles during the dispersion process is not sufficiently vaporized, evaporates and remains, so that the surface of the TiO2 particles is not fully exposed to the substrate. The top surface of the material cannot fully achieve the photocatalytic function. In addition, as a dispersant that vaporizes at a low temperature, an organic dispersant and a phosphoric acid series dispersant having a molecular weight of 10,000 or less are preferable.

Specific examples are listed below.

Example 1 A binder layer composed of SiO2-Al2O3-Na/K2O glass frit was formed by spraying on the surface of a 150 square ceramic tile substrate. After drying, a 15% TiO2 sol aqueous solution was sprayed by spraying. A TiO2 layer with a thickness of 0.8 μm is formed, and then the substrate on which the binder layer and the TiO2 layer are laminated is heated and fired in a roller hearth furnace (atmosphere temperature varies with different examples), and then cooled and solidified to obtain a multifunctional material.

Here, the so-called TiO2 sol aqueous solution is, for example, TiCl is hydrolyzed in an autoclave under hydrothermal conditions in the range of 100-200°C to obtain anatase TiO2 with a grain size of 0.007-0.2μm, and this TiO2 is sol State Disperse several to several tens of percent in acidic aqueous solutions such as nitric acid and hydrochloric acid or alkaline aqueous solutions such as ammonia. In order to improve dispersibility, triethanolamine and trimethylolamine can be added in the range of 0.5% or less. Surface treatment agents such as organic bases, pentaerythritol, trimethylolpropane, etc. In addition, the particle size of the TiO2 sol was processed using SEM (scanning electron microscope) observation, and the crystal particle size was calculated from the integral width of powder X-ray diffraction.

In addition, although the coating method is performed by spray coating, it is expected that the dip coating method and the spin coating method will also obtain the same results.

The obtained multifunctional material was evaluated for antibacterial properties and abrasion resistance.

Regarding antibacterial properties, the bactericidal effect on Escherichia coli (Escherichia coli W3110 strain) was tested. On the surface of the multifunctional material sterilized with 70% ethanol in advance, 0.15ml (1-5×104 CFU) of bacterial liquid was added dropwise, and placed on a glass plate (10×10 cm) close to the surface of the substrate as a sample. After irradiating with a white lamp (3500 lux) for 30 minutes, wipe the irradiated sample with sterile gauze and the bacterial solution of the sample maintained under the light-shielding condition, and recover it in 10ml of physiological saline to determine the survival rate of the bacteria. As an evaluation index.

Regarding the abrasion resistance, the sliding abrasion using a plastic rubber was evaluated, and the change in appearance was compared.

Table 1 below shows the changes in antibacterial and abrasion resistance when the base material is a ceramic tile with the change in the firing temperature of the binder SiO2-Al2O3-Na/K2O glass frit. (Table 1) Base material = ceramic tiles, binder = SiO2-Al2O3-Na/K2O glass frit photocatalyst = TiO2

+++: The survival rate of E. coli is 10% or less ++: The survival rate of E. coli is 10% or more and 30% or less +: The survival rate of E. coli is 30% or more and 70% or less -: The survival rate of E. coli is 70% or more : No change for 40 times of reciprocation : There are scratches in 10-40 times of sliding, and the photocatalyst layer (TiO2 film) peels off : There is scratches in 5-10 times of sliding, and the photocatalyst layer (TiO2 film) is peeled off × : There are scratches after sliding less than 5 times, and the photocatalyst layer (TiO2 film) peels off. Here, the specific gravity of the SiO2-Al2O3-Na/K2O glass frit used as the adhesive layer is 2.4, and the film thickness during coating is 200μm , The softening temperature is 680°C. In addition, in Table 1, of the obtained TiO2, No. 1-3 is anatase type with a specific gravity of 3.9, and Nos. 4 and 5 are rutile type with a specific gravity of 4.2.

In Table 1, the firing temperature of No. 1 is only 20°C higher than the softening temperature of the adhesive layer. In order to not sufficiently reduce the viscosity of the adhesive layer, the anatase-type TiO2 particles constituting the lowermost layer of the photocatalytic layer are not fully buried In the adhesive, so in the abrasion resistance test, there are scratches in 5-10 times of sliding, and it has been peeled off. This can be explained as the anatase type with excellent photocatalytic activity for antibacterial properties, and the TG-DTA observation results of TiO2 sol above 300°C indicate that the organic components are generally decomposed, vaporized, and attached to the surface of TiO2 The surface treatment agent and other dispersants are vaporized, but the calcination temperature is much higher than this temperature, that is, 700°C forms an excellent value of ++.

When the firing temperature of No. 3-5 is 800°C or higher and 1000°C or lower, the durability is very good, and there is no change even if the sliding test is performed more than 40 times. The reason for this is considered to be the formation of a necked part accompanying the initial firing of the TiO2 particles on the surface. In addition, when processed at 1100°C, cracks occurred on the TiO2 layer on the surface of the multifunctional material taken out from the roller hearth furnace after cooling and solidification. Judging from the TMA measurement of the TiO2 sample, it can be considered that this is caused by the mid-stage sintering accompanied by the significant shrinkage of the TiO2 particle volume.

No. 4 and No. 5 have poor antibacterial properties, both are -. It can be considered that there are two reasons. One is the phase transformation of TiO2 particles into rutile type, and the other is that the firing temperature is higher than the softening temperature of the binder layer by more than 300°C, the viscosity of the binder layer becomes too low, and the TiO2 particles constituting the photocatalyst layer are buried in In the adhesive layer. It cannot be considered as the reason for the transformation of TiO2 particles into rutile type. This is because although rutile TiO2 is also inferior to anatase TiO2, it still has certain activity in photocatalysis. For example, the TiO2 sol is sprayed directly on the porous alumina substrate, and after calcination at 950°C, the material obtained by cooling and solidifying has an antibacterial property of +. Therefore, it can be explained that the firing temperature is higher than the softening temperature of the adhesive layer by more than 300°C, the viscosity of the adhesive layer becomes too low, and the TiO2 particles constituting the photocatalyst layer are buried in the adhesive layer, which is also one of the reasons.

In addition, elemental analysis of Ti and Si (main components of the binder) such as EPMA in the cross-sectional direction of the sample was used to observe the mixed layer of Ti and Si, and it was confirmed that the photocatalyst particles TiO2 were buried.

The above example 1 confirmed the following facts when at least the photocatalyst was TiO2 and the binder layer was SiO2-Al2O3-Na/K2O glass frit.

(1) When the firing temperature is higher than the softening temperature of the adhesive layer by more than 20°C and no more than 300°C, the multifunctional material can be produced with good antibacterial and wear resistance. The reason is considered to be that in the above temperature range, the viscosity of the binder is adjusted to a value that enables TiO2 to be appropriately buried in the binder layer.

(2) It has been confirmed that in the multifunctional material made in (1), TiO2 particles are buried in the binder.

(3) When the firing temperature is 800°C or higher and 1000°C or lower, the abrasion resistance is excellent, and there is no change even in the sliding test for more than 40 times. It can be considered that a strong bond occurs with the formation of the necked part between the TiO2 particles.

Example 2 A binder layer composed of SiO2-Al2O3-PbO glass frit was formed by spraying on the surface of a 100×100×5 alumina substrate (alumina purity 96%). After drying, it was sprayed. A 15% TiO2 sol aqueous solution (same as Example 1) was applied to form a TiO2 layer with a thickness of 0.8μm. Then, the binder layer and TiO2 were laminated by heating and firing in a roller hearth furnace at a different atmosphere temperature depending on the example. The base material of the layer is then cooled and solidified to obtain a multifunctional material.

In Table 2 below, when the substrate is alumina, the changes in antibacterial properties and wear resistance are shown with the changes in the firing temperature of the binder SiO2-Al2O3-PbO glass frit. (Table 2) Substrate=Alumina plate (100×100×5), Binder=SiO2-Al2O3-PbO frit photocatalyst=TiO2

Here, the softening temperature of the SiO2-Al2O3-PbO glass used as the binder is 540°C, the specific gravity is 3.8, and the film thickness at the time of coating is 150 μm. In addition, the crystal form of TiO2 obtained is anatase.

In the abrasion resistance test of Table 2, No. 6 was scratched after 10 times of sliding and peeled off, but No. 7 and 8 were not scratched even after sliding more than 10 times. If there were, No. 9 got even There was no abrasion after sliding more than 40 times.

In Nos. 9 and 10, there was no scratch even after 40 or more slips. This is considered to be because the firing temperature is 800°C or higher, and necking is generated between the TiO2 particles, and the TiO2 particles are firmly bonded to each other.

In No. 6, there are scratches and peeling after sliding less than 10 times. This is considered to be because the firing temperature is only 20°C higher than the softening temperature of the binder, and the viscosity of the binder is not very low, which constitutes the photocatalyst layer. The anatase TiO2 particles in the bottom layer are not sufficiently buried in the binder layer.

On the contrary, in No. 7 and No. 8 there was no scratches even after 10 times of sliding. This is considered to be because the temperature of the necking formation temperature was not reached, but the difference between the firing temperature and the adhesive softening temperature was adjusted to make the adhesive sticky. The viscosity of the bonding agent is the value that TiO2 is appropriately buried in the adhesive layer.

On the other hand, in the antibacterial test of Table 2, No. 6-9 gave good results of +++ or ++, but No. 10 was +. This is considered to be because the calcination temperature is 320°C higher than the softening temperature of the binder, the viscosity of the binder is too low, and the TiO2 particles constituting the photocatalyst layer are buried in the binder layer.

Example 3 The SiO2-Al2O3-BaO glass frit was melted in the mold, cooled and solidified, and then processed to form a 100×100×1 glass flake, and a 15% TiO2 sol aqueous solution was sprayed on it (same as In Example 1), a TiO2 layer with a thickness of 0.8 μm was formed. After that, the glass flakes are placed on an alumina substrate (100×100×5), heated and fired in a silicon carbide rod furnace at a different atmosphere temperature depending on the example, and then cooled and solidified to obtain a multifunctional material.

Table 3 shows the changes in antibacterial and abrasion resistance as the firing temperature of the multifunctional material changes. (Table 3) Base material=Alumina plate (100×100×5), Binder=SiO2-Al2O3-BaO glass frit photocatalyst=TiO2

Here, the SiO2-Al2O3-BaO glass frit used as the binder has a softening temperature of 620°C and a specific gravity of 2.8. The crystal form of TiO2 on the multifunctional material is an anatase type, No.11-13, and No.14 It is a rutile type.

In the abrasion resistance test of Table 3, No. 11 has scratches and peeled off after sliding less than 10 times, but No. 12 has no scratches even after sliding more than 10 times. Further, No. 13, 14 Good results were obtained without scratches even after sliding more than 40 times.

No. 13 and No. 14 have no scratches even after 40 or more slips. It is considered that the firing temperature is 800°C or higher, and necking is formed between the TiO2 particles, and the TiO2 particles are firmly bonded to each other.

No. 11 was scratched and peeled after sliding less than 10 times. It can be considered that the firing temperature is only 20°C higher than the softening temperature of the adhesive, and the viscosity of the adhesive is not sufficiently low, which constitutes the sharpness of the lowermost layer of the photocatalyst layer. Titanite-type TiO2 particles cannot be fully buried in the binder layer.

In contrast, No. 12 has no scratches even after 10 times of sliding. It can be considered that although the firing temperature of the necking formation temperature is not reached, the difference between the firing temperature and the softening temperature of the binder is adjusted to make the binder The viscosity of TiO2 is moderately embedded in the binder layer.

On the other hand, in the antibacterial test in Table 3, No. 11-13 gave good results of +++ or ++, but No. 14 was -. It can be considered that this is caused by two reasons: TiO2 is rutile, and the firing temperature is 320°C higher than the softening temperature of the binder, the viscosity of the binder is too low, and the TiO2 particles constituting the photocatalyst layer are buried in the binder In the layer.

It can be confirmed from the above that the method of pre-coating TiO2 particles on the binder and then pasting it on the substrate to obtain a multifunctional material can also be used to coat the binder on the substrate and then coating the TiO2 particles. , To obtain the same effect as the method of multifunctional materials.

Example 4 An acrylic resin binder was coated on the surface of a 100×100×5 substrate made of polyimide resin, and then a 15% TiO2 sol aqueous solution was coated by spraying to form a film with a thickness of 0.8 μm The TiO2 layer is then fired in a nickel-chromium wire furnace at 150° C. The substrate on which the binder layer and the TiO2 layer are laminated.

Table 4 below shows the changes in antibacterial properties and abrasion resistance with changes in the firing temperature of the above-mentioned multifunctional materials.

(Table 4) Substrate=Polyimide resin, Binder=Acrylic resin Photocatalyst=TiO2, calcination temperature 150°C

In addition, in Table 4, the adjustment method of the 15% TiO2 sol aqueous solution was changed as follows.

No. 15: The 15% TiO2 sol aqueous solution used in Example 1 was used as it was.

No. 16: TiCl aqueous solution is hydrolyzed in an autoclave at 110-150°C, and then the product is adjusted to pH 0.8 with nitric acid, dispersed without using a surface modifier, and then used to remove agglomerates. Spraying is carried out immediately after removing the agglomerates.

Here, the specific gravity of TiO2 is 3.9, the crystal form is anatase, the specific gravity of acrylic resin is 0.9, and the temperature at which the viscosity corresponding to the softening point of glass is formed is 70°C.

Regarding abrasion resistance, under the conditions of Nos. 15 and 16, no scratches occurred even when sliding more than 10 times. It is considered that this is because the range of the difference between the firing temperature and the softening temperature of the binder can adjust the viscosity of the binder to a value that enables TiO2 to be appropriately buried in the binder layer.

On the other hand, regarding the antibacterial test, it was found that No. 15 was -, but No. 16 gave a good result of ++, and even at 30°C or less, a multifunctional material with antibacterial properties can be produced. In DTA-TG, the TiO2 sol of No. 15 has components that decompose and evaporate at 200-350°C, but it is not seen in No. 16, so the presence or absence of organic components covering TiO2 is the cause of this difference.

In addition, the specific gravity difference between anatase TiO2 and acrylic resin is 3, but it has been confirmed that under this degree of difference, the TiO2 particles constituting the photocatalyst layer are not buried in the binder layer, and they also have good antibacterial properties. Sex.

Example 5 On the surface of a 100×100×5 alumina substrate, a binder layer composed of glass frit whose specific gravity varies with each example was formed by spraying, and then dried, and then 15% TiO2 was sprayed by spraying. The sol aqueous solution is used to form a TiO2 layer with a film thickness of 0.8μm. Then, the substrate on which the adhesive layer and the TiO2 layer are laminated is heated and fired in a roller hearth furnace at an atmosphere temperature of 750°C, and then cooled and solidified to obtain a multifunctional material .

Table 5 below shows the changes in antibacterial and abrasion resistance of the above-mentioned multifunctional materials with changes in firing temperature. (Table 5) Substrate=Alumina plate (100×100×5), photocatalyst=TiO2

Regarding the antibacterial property test, No. 17-20 all got +++ good results. In each sample, the firing temperature is more than 30°C higher than the softening temperature of the softener. Below 300°C, it can be considered that the difference between the firing temperature and the softening temperature of the binder is within the range so that the viscosity of the binder is adjusted so that the TiO2 is appropriately buried in the viscosity. The value in the bonding agent layer.

Regarding the abrasion resistance, No. 17 had scratches and peeled off after sliding less than 5 times, but No. 18-20 had no scratches even after sliding more than 10 times.

The reason is that No. 17 is different from others in that the specific gravity of the binder is larger than that of TiO2, and the anatase TiO2 particles constituting the lowermost layer of the photocatalyst layer are not buried in the binder layer.

Therefore, the specific gravity of TiO2 and the binder affects the wear resistance of the multifunctional material. If the specific gravity of the binder is greater than that of TiO2, the wear resistance will become worse.

Example 6 On the surface of a 150 square ceramic tile substrate, a binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed, and TiO2 sol was sprayed, mixed and stirred on it. The aqueous solution formed by sol and SnO2 is then calcined at 750°C, cooled and solidified to obtain a multifunctional material.

In addition, the concentration of the TiO2 sol is 4-6% by weight, the pH is adjusted to 11 with an NH3 aqueous solution, the grain size of the TiO2 particles is 0.01 μm, and the grain size of the SnO2 particles is 0.0035 μm.

In the multifunctional material produced in this way, the amount of SnO2 (mol ratio) was changed with respect to the total amount of TiO2 and SnO2, and antibacterial and abrasion resistance tests were performed. The results are shown in Table 6 below.

(Table 6) Substrate = ceramic tiles, binder = SiO2-Al2O3-BaO glass frit photocatalyst = TiO2, interstitial particles = SnO2 (0.0035μm

Regarding the abrasion resistance test, it increased with the increase in the amount of SnO2. Since the addition of 10% or more, there was no scratch or change even in the 40 sliding tests.

Regarding the antibacterial property test, if it is in the range of 20% or more, it is +++ as in the case of no addition, and if it is 60%, it is limited to ++. If this is further increased, the probability of covering the TiO2 particles on the surface of the base material becomes higher, and the antibacterial property deteriorates, and it becomes-at 100%.

Therefore, in terms of mol ratio, if the addition amount of SnO2 is 10% or more and 60% or less of the total amount of TiO2 and SnO2, preferably 10% or more and 20% or less, it can provide excellent antibacterial and abrasion resistance. Multifunctional materials.

Here, the increase in wear resistance as the amount of SnO2 increases is due to the mechanism shown below: Because SnO2 vapor pressure is higher than TiO2 at a high temperature above 600°C, the spacing of TiO2 particles 3b before sintering is shown in Figure 17 ( a) shows Lo, but the vapor pressure on the surface of the TiO2 particle 3 with positive curvature becomes higher, and the surface with the negative curvature, that is, the surface vapor pressure of the necked part where two TiO2 particles 3b meet, becomes lower. As a result, as shown in Fig. 17(b), SnO2, which has a higher vapor pressure than TiO2, enters the necked part, condenses as shown in Fig. 17(c), and sinters according to the vaporization-condensation mechanism.

Furthermore, if sintering is performed according to the vaporization-condensation mechanism, the interval L2 of the TiO2 particles after sintering is approximately equal to the interval Lo before sintering, so no cracks are generated.

In a composite structure in which a layer of TiO2 particles is held on the surface of a substrate by an adhesive, SnO2 particles are filled in the gaps where the TiO2 particles on the outermost surface are exposed, and if sintered at 600°C or higher, cracks do not occur. , Because it can bond the necked part between the TiO2 particles, so the wear resistance is improved.

Comparative Example 7 is the same as Example 6. A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) is formed on the surface of the 150 square ceramic tile base material, and sprayed and mixed on it. An aqueous solution of TiO2 sol and SnO2 sol is stirred and then calcined at 750°C, cooled and solidified to obtain a multifunctional material.

In addition, the TiO2 sol concentration is 4-6% by weight, adjusted to pH 11 with NH3 aqueous solution, and the grain size of the particles is 0.01μm, the same as in Example 6, but the grain size of SnO2 particles is 0.008μm and slightly larger particle.

The antibacterial property test and the abrasion resistance test were performed on the multifunctional material produced in this way, and the results of comparison with Example 6 are shown in Table 7 below. (Table 7) Base material = ceramic tiles, binder = SiO2-Al2O3-BaO glass frit, photocatalyst = TiO2, interstitial particles = SnO2 (0.0080μm), heat treatment at 750°C

As a result, the effect of improving the wear resistance of 0.008μm SnO2 particles is weaker than when 0.0035μm SnO2 particles are used. The mol ratio to the total amount of TiO2 and SnO2 is about 60% or more, and there is no scratch even after 40 sliding tests. There is no change.

Regarding the antibacterial property test, as in the case of using 0.0035 μm SnO2 particles, if it is in the range of 20% or more, it is +++ as in the case of no addition, and if it is 60% or less, it is limited to ++. If this is further increased, the probability of covering the TiO2 particles on the surface of the base material becomes higher, and the antibacterial property deteriorates, which becomes-at 100%.

Therefore, when 0.01 μm TiO2 particles are used, it is difficult to obtain a multifunctional material with excellent antibacterial and abrasion resistance by adding 0.008 μm SnO2 particles. The reason can be considered to be because the vapor pressure becomes smaller as the SnO2 particle size increases. When the remaining SnO2 particles are 0.008μm without vaporization, the SnO2 particles are larger than the TiO2 particles, so the SnO2 particles do not enter the gaps. Of course, the probability of reaching the TiO2 particles becomes higher. This is in contrast to the situation where SnO2 exists in the gaps between the TiO2 particles when the remaining SnO2 particles are 0.0035μm without vaporization, and the bonding strength can be improved.

From the above point of view, the size of the SnO2 particles that should fill the gaps of the TiO2 particles relative to the diameter of the TiO2 particles is ideally 4/5 or less.

Example 8 A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed on the surface of a 150 square ceramic tile substrate, and a TiO2 sol aqueous solution was sprayed on it. It is calcined at 750°C, the cooled and solidified composite member is coated with a SnO2 sol aqueous solution by spraying method, and then heat-treated at 110°C to obtain a multifunctional material. At this time, the same solution as in Example 6 was used for the TiO2 sol aqueous solution, and 0.0035 μm was used for the SnO2 sol.

The antibacterial property test and the abrasion resistance test were performed on the multifunctional material thus produced, and the results are shown in Table 8 below.

(Table 8) Substrate = ceramic tiles, binder = SiO2-Al2O3-BaO glass frit photocatalyst = TiO2, interstitial particles = SnO2 (0.0035μm), heat treatment 750°C/110°C

Regarding the abrasion resistance test, it increases as the amount of SnO2 increases, and since the addition of 20% (mol ratio) or more, no scratches or changes occur even in 40 sliding tests.

Regarding the antibacterial property test, if it is in the range of 20% or more, it is +++ as in the case of no addition, and if it is 60%, it is limited to ++. If this is increased further, the probability of covering the TiO2 particles on the surface of the base material increases, and the antibacterial property deteriorates, which becomes-at 100%.

In this test, because the SnO2 sol was heat-treated at a low temperature of 110°C, sintering caused by the vaporization-condensation mechanism shown in Example 6 did not occur. Although the wear resistance is improved, this is believed to be because the particle size is smaller than that of TiO2 particles, that is, the specific surface area is larger, and the SnO2 particles with good adsorption capacity fill the gaps of TiO2 particles, thereby strengthening the bonding of TiO2 particles with each other.

Example 9 A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed on the surface of a 150 square ceramic tile substrate, and after coating the TiO2 sol aqueous solution on it by spraying, It is calcined at 750°C, and the composite member formed by cooling and solidification is coated with a copper acetate aqueous solution, dried, and then irradiated with ultraviolet light to reduce copper ions, and at the same time, it is fixed on the photocatalyst layer to obtain a multifunctional material. Here, a mercury lamp is used as the illumination lamp.

The Cu particles fixed on the photocatalyst layer here have an average size of about 0.004 μm.

The antibacterial property test and the abrasion resistance test were performed on the multifunctional material thus produced, and the results are shown in Table 9. (Table 9) Base material = ceramic tiles, binder = SiO2-Al2O3-BaO glass frit photocatalyst = TiO2, interstitial particles = Cu (0.004μm), heat treatment 750°C/light reduction

Regarding the abrasion resistance test, it increased as the amount of Cu increased, and due to the addition of 20% (mol ratio) or more, there was no scratch or change even in 40 sliding tests.

Regarding the antibacterial properties test, if it is in the range of 20% or more, it is +++ as in the case of no addition. Since Cu itself has antibacterial activity, no deterioration of antibacterial properties due to a large amount of addition is seen.

However, when the added amount of Cu is small, the photocatalytic effect of the TiO2 particle layer is dominant. When the added amount of Cu is large, it may be considered that the effect of Cu is dominant. In the case where only the effect of Cu is expected, since Cu is slowly eluted when used in a liquid, it can be considered that the life is shorter than that in the case of no photocatalyst. In addition, if the amount of Cu added increases, the cost of this part also increases. Therefore, it is considered meaningless to set the amount of Cu too much.

According to this embodiment, it has been confirmed that not only oxides such as SnO2, but also metals such as Cu can become particles that fill the gaps in the TiO2 particle layer.

Example 10 A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed on the surface of a 150 square ceramic tile substrate, and after spraying the TiO2 sol solution on it, It is calcined at 950°C, and the composite member formed by cooling and solidification is coated with a copper acetate aqueous solution, and then irradiated with ultraviolet light to reduce copper ions, and at the same time, it is fixed on the photocatalyst layer to obtain a multifunctional material.

At this time, the BLB lamp was used as the irradiation lamp, and the irradiation was performed for several minutes. TiO2 changes from anatase type to rutile type by heat treatment process. The film thickness of TiO2 during spraying was adjusted to 0.4 μm.

The antibacterial property test and the abrasion resistance test were performed on the multifunctional material made in this way. Regarding the abrasion resistance test, even if it is not added, it shows good results in this temperature region. Even if Cu was added, there was no scratch or change in the 40 sliding test as in the case of no addition.

The antibacterial test is shown in FIG. 18. When there is no addition, because TiO2 is rutile, it is not good +. Adding Cu to it increases the antibacterial properties. And not only when the BLB lamp is irradiated, but also when there is no irradiation, if the Cu loading is 0.7μg/cm2 or more, the antibacterial activity becomes ++, and if the Cu loading is 1.2μg/cm2 or more, the antibacterial activity becomes ++ +.

From the above point of view, in order to provide a multifunctional material with excellent antibacterial properties and abrasion resistance, the loading amount of Cu may be 0.7 μg/cm2 or more, more preferably 1.2 μg/cm2 or more.

However, after the copper acetate aqueous solution is applied and before the BLB lamp is irradiated, if the drying process is entered, the Cu loading will increase drastically. This relationship is shown in Figure 19. It is considered that this is because when drying is performed, the metal ion concentration during photoreduction is high.

In addition, when the coating amount is most suitable, the Cu loading amount becomes the largest (FIG. 20, FIG. 20 is an example of copper acetate with a Cu concentration of 1% by weight). In the case of FIG. 20, in order to make Cu support The loading amount is 0.7μg/cm2 or more, the coating amount can be 0.2mg/cm2 or more, 2.7mg/cm2 or less, in order to make the Cu loading amount is 1.2μg/cm2 or more, the Cu coating amount can be 0.3mg/cm2 or more , 2.4mg/cm2 or less.

Example 11 On the surface of a 150 square ceramic tile substrate, an adhesive layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 680°C) was formed, and after spraying an aqueous solution of TiO2 sol on it, The composite member is calcined at 950°C, and the cooled and solidified composite member is coated with a silver nitrate aqueous solution, dried, and then irradiated with ultraviolet light to reduce the silver ions and at the same time be fixed on the photocatalyst layer to obtain a multifunctional material.

A BLB lamp is used as the irradiation lamp, and it is irradiated for several minutes. In addition, TiO2 is transformed from anatase phase to rutile phase after heat treatment. The film thickness of TiO2 during spraying was adjusted to 0.4 μm.

The antibacterial property test and the abrasion resistance test were performed on the multifunctional material made in this way. Regarding abrasion resistance, even if it is not added, good results are shown in this temperature region. Even if Ag was added, there was no scratch or change in 40 sliding tests as in the case of no addition.

The antibacterial properties are shown in Fig. 70. When it is not added, TiO2 is a rutile type, so it is bad+. If Ag is added to it, the antibacterial properties increase. And not only when the BLB lamp is irradiated, but also when not irradiated, if the Ag loading is 0.05μg/cm2 or more, the antibacterial activity becomes ++, and if the Ag loading is 0.1μg/cm2 or more, the antibacterial activity becomes +++.

Therefore, in order to provide a multifunctional material with excellent antibacterial properties and abrasion resistance, the loading amount of Ag may be 0.05 μg/cm2 or more, and more preferably 0.1 μg/cm2 or more.

However, when the amount of Ag loading is large, the coloration changes from brown to black, and the appearance deteriorates. However, when the amount of Ag supported is 1 μg/cm2 or less, no coloration occurs.

From the above point of view, the amount of Ag supported may be 0.05 μg/cm2 or more and 1 μg/cm2 or more, and more preferably 0.1 μg/cm2 or more and 1 μg/cm2 or less.

Example 12 A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 680°C) was formed on the surface of a 150 square ceramic tile substrate, and after spraying the TiO2 sol solution on it, Baking at 950°C, coating a silver nitrate aqueous solution on the composite member formed by cooling and solidification, and drying, and then irradiating light containing ultraviolet rays to reduce the silver ions, while being fixed on the photocatalyst layer to obtain a multifunctional material.

At this time, a BLB lamp was used as the irradiation lamp, and the irradiation was performed for several minutes. In addition, TiO2 is transformed from anatase phase to rutile phase after heat treatment.

The multifunctional material made in this way was changed in the film thickness of TiO2, and abrasion resistance test, antibacterial property test, and pollution resistance test were performed.

Regarding the abrasion test, good results were shown within the range of 2 μm in the test, and there was no scratch or change even in the 40 sliding test.

In the antibacterial property test, when the film thickness is 0.1 μm or more, it becomes ++, and when it is 0.2 μm or more, it becomes +++. Therefore, the film thickness of TiO2 may be 0.1 μm or more, more preferably 0.2 μm or more.

Example 13 On the surface of a 150 square ceramic tile substrate, an adhesive layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed, and zinc chloride aqueous solution or zinc chloride solution was sprayed on it. After drying the TiO2 sol aqueous solution, apply the silver nitrate aqueous solution, and then irradiate the light containing ultraviolet light to reduce the silver ions and fix the silver ions on the photocatalyst layer. Then, the TiO2 sol solution is calcined at a temperature above 900°C and below 1000°C. Functional Materials.

At this time, the BLB lamp was used as the irradiation lamp, and the irradiation was performed for several minutes. In addition, TiO2 is transformed from anatase phase to rutile phase after heat treatment. And the Ag fixed on the surface changes from tea black to white with heat treatment, so it can be considered that it becomes silver oxide during firing. However, the attachment and fixation of Ag was completed discretely, and it was found through observation that there was almost no growth of Ag particles before and after firing.

The antibacterial property test and the abrasion resistance test were performed on the multifunctional material thus produced.

Regarding the abrasion resistance test, even if it is not added in this temperature range, it shows good results. Even if Ag was added, as with no addition, there was no scratch or change in 40 sliding tests.

The antibacterial property test is shown in Fig. 70. When it is not added, TiO2 is a rutile type, so it is not good+. If Ag is added to it, the antibacterial properties will increase.

Example 14 A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed on the surface of a 150 square ceramic tile substrate, and after coating the TiO2 sol aqueous solution on it by spraying, The composite member is calcined at above 900°C and below 1000°C, cooled and solidified, and coated with silver nitrate aqueous solution, and then irradiated with ultraviolet light to reduce the silver ions and fix it on the photocatalyst layer. Coat 0.1mol/L KI aqueous solution at a ratio of cc/cm2, and then irradiate it with ultraviolet rays for about 5 seconds to obtain a multifunctional material. At this time, the loading amount of Ag was 2 μg/cm2.

Since the 0.1 mol/L KI aqueous solution was coated at a ratio of 0.1cc/cm2 and then irradiated with ultraviolet rays for about 5 seconds, the original tea-black multifunctional material was bleached into white, and the appearance was improved.

Example 15 A binder layer composed of SiO2-Al2O3-BaO glass frit (softening temperature 620°C) was formed on the surface of a 150 square ceramic tile substrate, and after coating the TiO2 sol aqueous solution on it by spraying, Roast at 820°C, cool and solidify, place the obtained multifunctional material obliquely, irradiate light containing ultraviolet rays on the multifunctional material, and circulate the bath water collected from public baths on the multifunctional material, drip continuously, and observe the bath. Changes in water. In order to compare the same device, it was dripped on a substrate without a photocatalyst layer. Observed after 14 days, there is no special difference in turbidity between the bath water dripped on the above-mentioned multifunctional material and the bath water dripped on the substrate without the photocatalyst layer, but there is a difference in the smell of the sewer water. . The bath water dropped on the substrate without the photocatalyst layer has a strong sewage odor, and sludge-like mucus and organic precipitates are observed on the substrate. On the contrary, the dripping on the above-mentioned multifunctional material The water in the bath did not see those conditions. Through the above simulation tests, it can be considered that the multifunctional material can be used as paving stones for artificial waterfalls and fountains in water circulation methods such as parks and department stores.

As can be seen from the above description, in order to fix the photocatalyst particles by an adhesive layer composed of a material whose softening temperature is lower than that of the base material, it is particularly necessary to prevent the photocatalyst particles constituting the surface layer of the photocatalyst layer from being buried in the adhesive layer. The photocatalyst particles are substantially in a state where their surface is exposed to the outside, and can fully exhibit the photocatalytic effect. In addition, since a part of the particles constituting the lower layer of the photocatalyst layer among the photocatalyst particles is buried in the binder layer, the holding power of the photocatalyst layer is greatly improved, and peeling and the like are unlikely to occur.

FIG. 21 shows a manufacturing process diagram of another embodiment. In this embodiment, a thermoplastic material such as inorganic glass and a thermoplastic resin is used for the substrate 1, and the photocatalyst layer 2 is directly formed on the surface of the thermoplastic substrate 1.

That is, as shown in FIG. 21(a), a thermoplastic substrate 1 is prepared, and then as shown in FIG. 21(b), a photocatalyst layer 2 composed of photocatalyst particles such as TiO2 particles is formed on the surface of the thermoplastic substrate 1. After that, as shown in FIG. 21(c), after heat treatment, the lower layer on the thermoplastic substrate side in the photocatalyst layer 2 settles on the thermoplastic substrate, is solidified and embedded in the thermoplastic substrate, and is firmly held. In addition, the photocatalyst particles 3 constituting the surface layer in contact with the air in the photocatalyst layer 2 are combined by potential energy, mutual intermolecular force, or sintering.

Although the preferred conditions and the like of this embodiment are the same as those of the above-mentioned embodiment, specific embodiments will be described below.

Example 16 On the surface of a glass substrate composed of 150 square SiO2-Al2O3-Na/K2O, a 15% TiO2 sol aqueous solution was sprayed to form a TiO2 layer with a thickness of 0.8μm, and then TiO2 was laminated The glass substrate of the layer is placed in a ceramic mold with good release properties, heated and fired in a roller hearth furnace at a different atmosphere temperature according to different examples, and then cooled and solidified to obtain a multifunctional glass.

Here, the so-called TiO2 sol aqueous solution is prepared as follows: For example, TiCl4 is hydrolyzed in an autoclave under hydrothermal conditions in the range of 100-200°C to obtain anatase TiO2 with a grain size of about 0.007-0.2μm. Disperse the TiO2 in a sol state in an acidic aqueous solution such as nitric acid and hydrochloric acid or an alkaline aqueous solution such as ammonia to a few percent to tens of percent; in order to improve the dispersibility, the surface treatment agent triethanolamine is added in the range of 0.5% or less And organic bases such as trimethylolamine, pentaerythritol, trimethylolpropane, etc. to obtain TiO2 sol aqueous solution. In addition, the particle size of the TiO2 sol was obtained by image processing of SEM observation, and the crystal particle size was calculated from the integrated width of powder X-ray diffraction.

In addition, although the coating method is performed by spray coating, it is expected that the same results can be obtained by dip coating and spin coating.

The antibacterial properties and abrasion resistance of the obtained multifunctional glass were evaluated.

Regarding antibacterial properties, the bactericidal effect on Escherichia coli (Escherichia coli W3110 strain) was tested. Drop 0.15 ml of bacterial solution (1-5×104 CFU) on the outermost surface of the multifunctional glass pre-sterilized with 70% ethanol, and place it on the glass plate (10×10cm) to closely adhere to the outermost surface of the substrate as a sample. After irradiating with a white light (3500 Lux) for 30 minutes, wipe the irradiated sample with sterile cotton yarn and the bacterial solution of the sample kept under the shielded condition, and recover it in 10ml of physiological saline to obtain the survival rate of the bacteria as Evaluation index.

Regarding the abrasion resistance, a plastic rubber was used for sliding abrasion, and the appearance change was compared and evaluated.

Table 10 below shows the use of a glass substrate composed of SiO2-Al2O3-Na/K2O, and the changes in antibacterial properties and wear resistance with changes in the firing temperature. (Table 10) Substrate=SiO2-Al2O3-Na/K2O glass photocatalyst=TiO2<

>+++: The survival rate of E. coli is 10% or less ++: The survival rate of E. coli is 10% or more and 30% or less +: The survival rate of E. coli is 30% or more and 70% or less -: The survival rate of E. coli is 70% or more : No change to 40 times of reciprocation : Scratches in 10-40 times of sliding, and peeling of the photocatalyst layer (TiO2 film) : Scratches in 5-10 times of sliding, and peeling of the photocatalyst layer (TiO2 film) ×: Scratches occurred after 5 times or less sliding, and the photocatalyst layer (TiO2 film) was peeled. Here, the specific gravity of the glass substrate composed of SiO2-Al2O3-Na/K2O is 2.4, and the softening temperature is 680°C. In addition, in Table 10, the obtained TiO2, No. 1-3 is anatase type with a specific gravity of 3.9, and Nos. 4 and 5 are rutile type with a specific gravity of 4.2.

In Table 10, the firing temperature of No. 1 is only 20°C higher than the softening temperature of the glass substrate. Since the viscosity of the glass substrate cannot be sufficiently low, the anatase-type TiO2 particles constituting the lowermost layer of the photocatalyst layer are not It is fully buried in the glass substrate, so in the abrasion resistance test, there are scratches and peeling after 5-10 times of sliding. In addition, because it is an anatase type with excellent photocatalytic activity; and the TG-DTA observation of the TiO2 sol at a temperature above 300°C reveals that the organic components are basically decomposed, vaporized, and the surface treatment agent attached to the TiO2 surface is dispersed. The agent vaporizes, but the calcination temperature is 700°C, which is a heat treatment temperature considerably higher than this temperature, so the antibacterial property becomes an excellent value of ++.

Although the firing temperature of No. 3-5 was 800°C or more and 1000°C or less, there was no change in the wear resistance even after 40 or more sliding tests. It is very good. The reason for this is considered to be the formation of the necked part accompanying the initial firing of the TiO2 particles on the surface. In addition, when processed at 1100°C, cracks occurred on the TiO2 layer on the surface of the multifunctional glass taken out of the roller hearth furnace after cooling and solidification. Judging from the TMA measurement of the TiO2 sample, this can be considered to be caused by the mid-stage sintering accompanied by the significant volume shrinkage of the TiO2 particles.

The antibacterial properties of No. 4 and 5 are both -, which is poor. It can be considered that there are two reasons for this: one is that the phase of TiO2 particles transforms into rutile, and the other is that the firing temperature is 300°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate is too low, which constitutes the TiO2 particles of the photocatalyst layer Buried in the glass substrate. The reason why the TiO2 particle phase transforms into rutile type cannot be considered here. This is because even in rutile TiO2, it is inferior to anatase, but it still has a certain degree of photocatalytic activity. For example, the TiO2 sol is sprayed directly on the porous alumina substrate, and after calcination at 950°C, the antibacterial property of the material obtained by cooling and solidifying is +. Therefore, it can be explained that the firing temperature is 300°C higher than the softening temperature of the glass substrate, the viscosity of the glass substrate is too low, and the TiO2 particles forming the photocatalyst layer are buried in the glass substrate, which is another reason.

In addition, through elemental analysis of Ti and Si (main components of the glass substrate) such as EPMA in the cross-sectional direction of the sample, observation of the layer where Ti and Si are mixed, it was confirmed that the photocatalyst particles TiO2 were buried.

In the above example 16, when at least the photocatalyst is TiO2 and the glass substrate is composed of SiO2-Al2O3-Na/K2O, the following facts have been confirmed.

(1) When the multifunctional glass is manufactured under the condition that the firing temperature is 20°C higher than the softening temperature of the glass substrate and not higher than 300°C, the multifunctional glass with good antibacterial and abrasion resistance can be manufactured. The reason for this is considered to be that the viscosity of the glass substrate is adjusted to a value such that TiO2 is appropriately buried in the glass substrate in the above-mentioned temperature range.

(2) In the multifunctional glass made in (1), it has been confirmed that TiO2 particles are buried in the glass substrate.

(3) When the firing temperature is 800°C or higher and 1000°C or lower, the abrasion resistance does not change even after 40 or more sliding tests, which is extremely good. It can be considered that it is caused by the formation of the necking between the TiO2 particles, resulting in a strong bond.

Example 17 On the surface of a 100×100×5 glass substrate composed of SiO2-Al2O3-PbO, a 15% TiO2 sol aqueous solution (same as in Example 16) was sprayed to form TiO2 with a film thickness of 0.8μm. Then, the glass substrate laminated with the TiO2 layer is placed in a ceramic mold with good release properties, heated and fired in a roller hearth furnace at a different atmosphere temperature depending on different examples, and then cooled and solidified to obtain a Functional glass.

In the following Table 11, when a glass substrate composed of SiO2-Al2O3-PbO is used, the changes in antibacterial and abrasion resistance are shown as the firing temperature changes.

(Table 11) Substrate = SiO2-Al2O3-PbO glass photocatalyst = TiO2

Here, the softening temperature of the glass substrate composed of SiO2-Al2O3-PbO is 540°C, the specific gravity is 3.8, and the crystal form of the obtained TiO2 is anatase.

In the abrasion resistance test of Table 11, No. 6 had scratches and peeled off after sliding less than 10 times, but No. 7 and 8 had no scratches even after sliding more than 10 times. Again, No. 9.10. The good result is that there is no scratch even after sliding more than 40 times.

In Nos. 9 and 10, there was no scratches even after 40 or more slips. It is believed that the firing temperature was 800°C or higher, so necking was formed between the TiO2 particles and the TiO2 particles were firmly bonded to each other.

In No.6, there are scratches and peeling after sliding less than 10 times. It is considered that the firing temperature is only 20°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate cannot be sufficiently low to form the photocatalyst layer. The anatase TiO2 particles are not fully buried in the glass substrate.

On the contrary, in No. 7 and No. 8, there was no scratches even after 10 times of sliding. It can be considered that although the necking temperature is not reached, the difference between the firing temperature and the softening temperature of the glass substrate is adjusted to make the glass The viscosity of the substrate makes the TiO2 moderately buried in the glass substrate.

On the other hand, in the antibacterial test of Table 11, No. 6-9 gave good results of +++ or ++, but No. 10 became +. It is considered that this is because the firing temperature is 320°C higher than the softening temperature of the glass substrate, the viscosity of the glass substrate is too low, and the TiO2 particles constituting the photocatalyst layer are buried in the glass substrate.

Example 18 On the surface of a 100×100×5 glass substrate composed of SiO2-Al2O3-BaO, a 15% TiO2 sol aqueous solution (same as in Example 1) was sprayed to form a TiO2 layer with a thickness of 0.8μm . Then, the glass substrate laminated with the TiO2 layer is placed in a ceramic mold with good release properties, heated and fired in a nickel-chromium wire furnace at a different atmosphere temperature according to different examples, and then cooled and solidified to obtain a multifunctional glass .

Table 12 below shows the changes in antibacterial properties and wear resistance with changes in the firing temperature of the above-mentioned multifunctional glass. (Table 12) Substrate = SiO2-Al2O3-BaO glass photocatalyst = TiO2

Here, the softening temperature of the glass substrate composed of SiO2-Al2O3-BaO is 620°C, the specific gravity is 2.8, the crystal form of TiO2 on the multifunctional glass, No.11-13 is anatase type, No.14 is rutile type .

In the abrasion resistance test of Table 12, No. 11 has scratches and peeled off after sliding less than 5 times, but No. 12 has no scratches even after sliding more than 10 times. Furthermore, No.13, 14 A good result was obtained that there was no scratch even after sliding more than 40 times.

No. 13 and No. 14 have no scratches even after 40 or more slips. It is considered that the firing temperature is 800°C or higher, and necking is formed between the TiO2 particles, and the TiO2 particles are firmly bonded to each other.

No. 11 has scratches and peeling after sliding less than 10 times. It is considered that the firing temperature is only 20°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate is not low enough to form the lowermost layer of the photocatalyst layer. The anatase TiO2 particles are not fully buried in the glass substrate.

In contrast, No. 12 has no scratches even after more than 10 sliding times. It is considered that although the temperature for forming the necked part is not reached, the difference between the firing temperature and the softening temperature of the glass substrate is adjusted to make the glass substrate The viscosity of the material makes the TiO2 particles embedded in the glass substrate moderately.

On the other hand, in the antibacterial property test of Table 12, No. 11-13 had good results of +++ or ++, but No. 14 was -. This can be considered due to two reasons: one is that TiO2 is rutile, and the other is that the firing temperature is 320°C higher than the softening temperature of the glass substrate. The viscosity of the glass substrate is too low, and the TiO2 particles constituting the photocatalyst layer are embedded in the glass. In the base material.

Example 19 A 15% TiO2 sol aqueous solution was sprayed on the surface of a 100×100×5 glass substrate with different specific gravities depending on different examples to form a TiO2 layer with a thickness of 0.8 μm, and then laminated The TiO2 glass substrate is placed in a ceramic mold with good release properties, heated and fired in a roller hearth furnace with an atmosphere temperature of 750°C, and then cooled and solidified to obtain a multifunctional glass.

The following Table 13 shows the changes in antibacterial properties and abrasion resistance in accordance with the changes in the specific gravity of the glass substrate of the above-mentioned multifunctional glass. (Table 13) Photocatalyst = TiO2

Regarding the antibacterial property test, No. 15-18 all obtained good results of +++. It is considered that in each of these, the firing temperature is higher than the softening temperature of the glass substrate by 30°C or more and 300°C or less, and the difference between the firing temperature and the glass substrate softening temperature is adjusted to make the glass substrate soften. Viscosity is the value that TiO2 is appropriately embedded in the glass substrate.

Regarding abrasion resistance, No. 15 had scratches and peeled after sliding less than 5 times, and No. 16-18 had no scratches even after sliding more than 10 times.

The reason can be considered to be because No. 15 is different from others. The specific gravity of the glass substrate is larger than that of TiO2. The anatase TiO2 particles that constitute the lowermost layer of the photocatalyst layer are not sufficiently buried in the glass substrate, so it is clear that TiO2 The specific gravity of the glass substrate also affects the wear resistance of the multifunctional glass. The specific gravity of the glass substrate is greater than the specific gravity of TiO2, which deteriorates the wear resistance.

Example 20: On a glass substrate composed of 150 square SiO2-Al2O3-BaO (softening temperature 620°C), the aqueous solution obtained by mixing and stirring TiO2 sol and SnO2 sol was sprayed, and then heated at 750°C. After firing, cooling and solidification, a multifunctional glass is obtained.

The concentration of the TiO2 sol is 4-6% by weight, adjusted to pH 11 with an aqueous NH3 solution, the grain size of the TiO2 particles is 0.01 μm, and the grain size of the SnO2 particles is 0.0035 μm.

For the multifunctional glass produced in this way, various SnO2 amounts (mol ratios) relative to the sum of TiO2 and SnO2 were changed, and antibacterial properties and abrasion resistance tests were performed. The results are shown in Table 14 below. (Table 14) Substrate = SiO2-Al2O3-BaO glass photocatalyst = TiO2, interstitial particles = SnO2 (0.0035μm)

Regarding the abrasion resistance test, it increased with the increase in the amount of SnO2, and because of the addition of 10% or more, there was no scratch or change even in 40 sliding tests.

Regarding the antibacterial property test, if it is in the range of 20%, it will be +++ as in the case of no addition, and if it is 60%, it will be limited to ++. If it is increased further, the probability of covering the TiO2 particles on the surface of the glass substrate becomes high, and the antibacterial property is inferior, and it becomes -100%.

Therefore, the molar ratio of SnO2 added to the total amount of TiO2 and SnO2 is 10% or more and 60% or less, preferably 10% or more and 20% or less. It can provide a multifunctional glass with excellent antibacterial and abrasion resistance. .

Here, the abrasion resistance increases as the amount of SnO2 increases, which is caused by the mechanism illustrated in FIG. 17.

In this way, in a composite structure in which a layer of TiO2 particles is held on the surface of the glass substrate through a glass substrate, if the exposed TiO2 particles are filled with SnO2 particles and fired at 600°C or higher, cracks will not occur because of the energy The necked part between the TiO2 particles is combined, so the wear resistance is improved.

Comparative Example 21 is the same as Example 20. On the surface of a glass substrate composed of 150 square SiO2-Al2O3-BaO (softening temperature 620°C), it is formed by spraying TiO2 sol and SnO2 sol and mixing and stirring. The aqueous solution is then fired at 750°C, cooled and solidified to obtain multifunctional glass.

The TiO2 sol concentration is 4-6% (weight), adjusted to pH 11 with NH3 aqueous solution, the grain size of the particles is the same as that of Example 5, which is 0.01μm, but the crystal grain size of SnO2 particles is 0.008μm and slightly larger Particle size.

The antibacterial and abrasion resistance tests were performed on the multifunctional glass produced in this way, and the results of comparison with Example 5 are shown in Table 15 below.

(Table 15) Substrate = SiO2-Al2O3-BaO glass photocatalyst = TiO2, interstitial particles = SnO2 (0.0080μm), heat treatment at 750°C

As a result, the effect of 0.008μm SnO2 particles in improving the wear resistance is weaker than when 0.0035μm SnO2 particles are used. When the mol ratio to the total amount of TiO2 particles and SnO2 particles is gradually 60% or more, even after 40 times There was no scratch or change in the sliding test.

Regarding the antibacterial property test, as in the case of using SnO2 particles of 0.0035 μm, if it is in the range of 20%, it is +++ as in the case of no addition, and if it is 60% or less, it is limited to ++. If it is increased further, the probability of covering the TiO2 particles on the surface of the glass substrate increases, and the antibacterial property deteriorates, and it becomes -100%.

Therefore, when using 0.01 μm TiO2 particles, adding 0.008 μm SnO2 particles makes it difficult to obtain a multifunctional glass with excellent antibacterial properties and abrasion resistance. The reason can be considered to be because the vapor pressure of SnO2 particles becomes smaller as the particle size increases, and when the unvaporized remaining SnO2 particles are 0.0035μm, they exist in the gaps between the TiO2 particles to increase the bonding strength, on the contrary When the SnO2 particles are 0.008μm, compared with the TiO2 particles, the SnO2 particles are larger. Therefore, the Sn2O particles do not enter the gap, and the probability of naturally reaching the TiO2 particles increases.

It can be seen from the above that the size of the SnO2 particles that should fill the gaps between the TiO2 particles is ideally 4/5 or less with respect to the TiO2 particle size.

Example 22: On the surface of a glass substrate composed of 150 square SiO2-Al2O3-BaO (softening temperature 620°C), a TiO2 sol aqueous solution was sprayed on, then fired at 750°C and solidified after cooling. After coating the SnO2 sol aqueous solution on the composite member by spraying, it is heat-treated at 110°C to obtain the multifunctional glass. At this time, the TiO2 sol aqueous solution was the same as in Example 5, and the SnO2 sol was 0.0035 μm.

The antibacterial and abrasion resistance tests were performed on the multifunctional glass thus produced, and the results are shown in Table 16 below. (Table 16) Substrate = SiO2-Al2O3-BaO glass photocatalyst = TiO2, interstitial particles = SnO2 (0.0035μm), heat treatment 750°C/110°C

</tables> Regarding the abrasion resistance test, it increased with the increase of the amount of SnO2. Since the addition of 20% (mol ratio) or more, there was no scratch or change even in 40 sliding tests.

Regarding the antibacterial property test, if it is in the range of 20%, it will be +++ as in the case of no addition, and if it is 60%, it will be limited to ++. If it is increased further, the probability of covering the TiO2 particles on the surface of the glass substrate increases, and the antibacterial property deteriorates, and it becomes -100%.

In this test, since the SnO2 sol was heat-treated at a low temperature of 110°C, sintering caused by the vaporization-condensation mechanism shown in Example 5 did not occur. Although the wear resistance is improved, it can be considered that this is because the particle size is smaller than the TiO2 particles, that is, the specific surface area becomes larger, and the SnO2 particles with good adsorption capacity fill the gaps between the TiO2 particles, thus strengthening the bonding between the TiO2 particles.

Example 23: On a glass substrate composed of 150 square SiO2-Al2O3-BaO (softening temperature 620°C), a TiO2 sol aqueous solution was sprayed, then fired at 750°C, and then cooled and solidified. The component is coated with a copper acetate aqueous solution and dried, and then irradiated with ultraviolet light to reduce the copper ions and at the same time be fixed on the photocatalyst layer to obtain a multifunctional glass. A mercury lamp is used as the illumination lamp here.

Here, the Cu particle size fixed on the photocatalyst layer is about 0.004 μm on average.

The results of the antibacterial and abrasion resistance tests on the multifunctional glass thus produced are shown in Table 17 below. (Table 17) Substrate = SiO2-Al2O3-BaO glass photocatalyst = TiO2, interstitial particles = SnO2 (0.004μm), heat treatment 750°C/light reduction

Regarding the wear resistance, it increases as the amount of Cu is increased, and since 20% (mol ratio) or more is added, there is no scratch or change even in 40 sliding tests.

Regarding the antibacterial property test, if it is in the range of 20% or more, it is +++ as in the case of no addition. Since Cu itself has antibacterial activity, no deterioration in antibacterial properties due to a large amount of addition is observed.

However, it can be considered that when the addition amount of Cu is small, the photocatalytic effect caused by the TiO2 particle layer is dominant, and when the addition amount of Cu is large, the effect caused by Cu is dominant. In the case where only the effect of Cu is expected, it is considered that since Cu is slowly eluted when used in a liquid, it is considered that the life is shorter than the case without a photocatalyst. In addition, if the addition amount of Cu is large, the cost of this part is also high. Therefore, it can be considered that it is meaningless to set the amount of Cu excessively.

It has been confirmed by this example that not only oxides such as SnO2, but also metals such as Cu can also become particles that fill the gaps in the TiO2 particle layer.

Example 24: On the surface of a 150 square glass substrate composed of SiO2-Al2O3-BaO (softening temperature 620°C), the TiO2 sol aqueous solution was sprayed, then fired at 950°C and solidified after cooling. The composite member is coated with a copper acetate aqueous solution, and then irradiated with ultraviolet light to reduce copper ions, and at the same time, it is fixed on the photocatalyst layer to obtain a multifunctional glass.

At this time, the BLB lamp was used as the irradiation lamp, and the irradiation was performed for several minutes. TiO2 changes from anatase type to rutile type by heat treatment. The film thickness of TiO2 was adjusted to 0.4μm during spraying.

The antibacterial and abrasion resistance tests were performed on the multifunctional glass thus produced. Regarding the abrasion resistance test, even if it is not added, it shows good results in this temperature region. Even if Cu was added, it was the same as when there was no addition, and there was no scratch or change even in 40 sliding tests.

The antibacterial test is shown in Fig. 22. When not added, since TiO2 is rutile, it is poor +. If Cu is added to it, the antibacterial properties are improved. And not only when the BLB lamp is irradiated, but also when not irradiated, if the loading amount of Cu becomes 0.7μg/cm2 or more, the antibacterial activity becomes ++, and if the loading amount of Cu becomes 1.2μg/cm2, the antibacterial activity becomes +++ .

As can be seen from the above, in order to provide a multifunctional glass with excellent antibacterial properties and abrasion resistance, the Cu loading amount may be 0.7 μg/cm2, and more preferably 1.2 μg/cm2.

However, if the copper acetate aqueous solution is applied and before the BLB lamp is irradiated, it enters the drying process, the Cu loading amount is drastically increased. This relationship is shown in Figure 23. It is considered that this is because the metal ion concentration during photoreduction during drying is high.

In addition, when the Cu coating amount is optimized, the Cu loading amount becomes the largest (FIG. 24, an example of copper acetate with a Cu concentration of 1% by weight). In FIG. 24, in order to make the Cu loading amount 0.7 For μg/cm2 or more, the coating amount can be 0.2mg/cm2 or more and 2.7mg/cm2 or less. In order to make the Cu loading amount 1.2μg/cm2 or more, the coating amount can be 0.3mg/cm2 or more and 2.4mg /cm2 or less.

Example 25 A TiO2 sol aqueous solution was sprayed on the surface of a glass substrate composed of 150 square SiO2-Al2O3-BaO (softening temperature 680°C), and then calcined at 950°C and solidified after cooling. The composite member is coated with an aqueous silver nitrate solution, dried, and then irradiated with ultraviolet light to reduce the silver ions, while being fixed on the photocatalyst layer to obtain a multifunctional glass.

At this time, the BLB lamp was used as the irradiation lamp, and the irradiation was performed for several minutes. In addition, TiO2 is transformed from anatase phase to rutile phase after heat treatment. The thickness of the TiO2 film was adjusted to 0.4μm during spraying.

The antibacterial and abrasion resistance tests were performed on the multifunctional glass thus produced. Regarding abrasion resistance, even if it is not added, good results are obtained in this temperature region. Even if Ag was added, it was the same as without adding, and there was no scratch or change even in 40 sliding tests.

The antibacterial test is shown in Fig. 25. When it is not added, TiO2 is rutile, so it is poor +. If Ag is added to it, the antibacterial properties are improved. And not only when the BLB lamp is irradiated, but also when not irradiated, if the Ag loading is 0.05μg/cm2 or more, the antibacterial activity becomes ++, and if the Ag loading is 0.1μg/cm2, the antibacterial activity becomes ++ +.

Therefore, in order to provide a multifunctional glass with excellent antibacterial properties and abrasion resistance, the loading amount of Ag may be 0.05 μg/cm2 or more, more preferably 0.1 μg/cm2 or more.

However, if the amount of Ag supported is large, it will be colored from brown to black, and the appearance will be deteriorated. However, if the amount of Ag supported is 1 μg/cm2 or less, there is no coloring.

As can be seen from the above, the amount of Ag supported may be 0.05 μg/cm2 or more and 1 μg/cm2 or less, and more preferably 0.1 μg/cm2 or more and 1 μg/cm2 or less.

Example 26: On the surface of a 150 square glass substrate composed of SiO2-Al2O3-BaO (softening temperature 680°C), the TiO2 sol aqueous solution was coated by spraying method, and then calcined at 950°C and solidified after cooling. The composite member is coated with an aqueous silver nitrate solution, dried, and then irradiated with ultraviolet light to reduce the silver ions, while being fixed on the photocatalyst layer to obtain a multifunctional glass.

At this time, the BLB lamp was used as the irradiation lamp, and the irradiation was performed for several minutes. In addition, TiO2 changes from anatase type to rutile type after heat treatment.

The multifunctional glass thus prepared was subjected to abrasion resistance test, antibacterial property test, and stain resistance test to vary the film thickness of TiO2.

Regarding the abrasion resistance test, good results were shown in the range of the test film thickness within 2 μm, and there was no scratch or change even in 40 sliding tests.

In the antibacterial property test, it becomes ++ when the film thickness is 0.1 μm or more, and becomes +++ when the film thickness is 0.2 μm or more. Therefore, the film thickness of TiO2 may be 0.1 μm or more, more preferably 0.2 μm or more.

As can be seen from the above description, because the photocatalyst particles are to be fixed on the thermoplastic substrate, especially the photocatalyst particles constituting the surface layer of the photocatalyst layer are not embedded in the thermoplastic substrate, the photocatalyst particles are substantially formed. The state where the surface is exposed to the outside can fully exhibit the photocatalytic effect. In addition, since a part of the particles constituting the lower layer of the photocatalyst layer among the photocatalyst particles is embedded in the thermoplastic substrate, the holding power of the photocatalyst is greatly improved, and peeling and the like are less likely to occur.

Figures 26 and 27 are conceptual diagrams of the basic distribution when observing the cross-sectional direction of the multifunctional material with EPMA (Electron Beam Microanalyzer). As shown in these figures, starting from the surface in contact with air, a region (A region) where the concentration of the components constituting the photocatalyst layer 2 is approximately constant follows, and thereafter the components constituting the photocatalyst layer decrease. In addition, the components constituting the amorphous layer (binder layer) are not absent or small on the surface, and the concentration increases as they enter the interior. And when the film thickness reaches a certain level, the component concentration is approximately constant (zone B). Here, the A region is defined as the photocatalyst layer, the B region is defined as the amorphous layer, and the middle C region is defined as the intermediate layer. However, FIG. 26 is a conceptual diagram for the convenience of explanation after all. It is essentially as shown in FIG. 27. In the portion with a constant concentration described in FIG. 26, the concentration is often changed due to the manufacturing process. In this case, as shown in Figure 27, the minimum concentration of the area (A' area, B'area) corresponding to a certain area is regarded as A'area and C'area, B'area and C'area respectively. Borders.

Here, the thickness of the photocatalyst layer is the thickness of the A region or the A'region, and the thickness of the intermediate layer is the thickness of the C region or the C'region.

The thickness of the intermediate layer can be changed by controlling the moving speed and possible time of the photocatalyst particles into the softened amorphous layer. The moving speed can be controlled by the difference in specific gravity between the photocatalyst particles and the amorphous layer, the calcination temperature, and the atmospheric pressure. In addition, the possible time of movement can be changed by changing the retention time of the amorphous material at the softening temperature.

If the thickness of the intermediate layer is 1/3 or more of the thickness of the photocatalyst layer, the adhesiveness can be further increased.

The following describes specific embodiments.

Example 27 A SiO2-Al2O3-Na/K2O system amorphous layer was formed by spraying on a 10cm square alumina substrate. After drying and firing, a 0.01μm TiO2 sol aqueous solution was sprayed by spraying. Calcination was performed at 850°C and varying holding time to form anatase TiO2 thin films of 0.2 μm, 0.5 μm, and 1 μm. Next, a copper acetate aqueous solution was sprayed on the anatase TiO2 film, and then photoreduction was performed (the light source was a 20-watt BLB lamp, the distance from the light source to the sample was 10 cm, and the irradiation time was 30 seconds) to obtain a test kind. About the obtained sample, the cross-sectional element analysis (Ti, Si) of EPMA was used to measure the film thickness to evaluate the antibacterial property and abrasion resistance.

For the evaluation of antibacterial properties, Escherichia coli (Escherichia coli W3110 strain) was used for the test. Drop 0.15 ml (1-50000 CFU) of the bacterial liquid on the outermost surface of the multifunctional component pre-sterilized with 70% ethanol, place it on a glass plate (100×100), and make it adhere to the outermost surface of the substrate as a sample. After irradiating with a white light (3500 Lux) for 30 minutes, the irradiated sample bacterial solution was wiped with sterile gauze, and recovered in 10 ml of physiological saline, and the bacterial survival rate was determined as an evaluation index. The evaluation criteria are the same as those in Table 1 above.

The results are summarized in Table 18. All about antibacterial properties are +++.

Abrasion resistance, or both indicate good results. In particular, samples with a ratio of the thickness of the intermediate layer to the thickness of the photocatalyst layer of 1/3 or more are all . (Table 18)<

Example 28: On a 10cm square alumina substrate, an ammonia dispersion of TiO2 sol with an average particle size of 0.01μm was sprayed by spraying, and it was fired at 850°C to form an anatase TiO2 thin film with a thickness of 1μm . Next, on the anatase-type TiO2 thin film, a copper acetate aqueous solution was coated by spraying, and then photoreduction was performed (the light source was a 20-watt BLB lamp, the distance from the light source to the sample was 10 cm, and the test was irradiated for 30 seconds). kind. The antibacterial properties and abrasion resistance were evaluated for the obtained samples.

As a result, the antibacterial property was good +++, but the abrasion resistance was , which was insufficient.

From the above description, it can be seen that when the photocatalyst layer is held on the surface of the substrate through the amorphous layer, the upper part of the photocatalyst layer is exposed in contact with the air, and the photocatalyst layer has light in which the particles are combined with each other. Among the multifunctional materials with catalytic function, the amorphous layer and the photocatalyst layer should have an intermediate layer in which the component concentrations of both are continuously changed between them. This can increase the adhesion between the photocatalyst film and the substrate and improve the peeling resistance. . Furthermore, making the thickness of the intermediate layer more than 1/3 of the thickness of the photocatalyst layer can further increase the adhesion.

The following describes the case where the photocatalyst layer 2 is formed by sintering. Figure 1(a) is a diagram showing the state of the conventional TiO2 particles before sintering, and (b) is a diagram showing the state after sintering. As shown in Figure 1(a), the surface of the substrate 1 is coated with TiO2 particles 3 Sol. If it is heat-treated (sintered) in order to increase the film strength, cracks 2a are likely to occur as shown in Fig. 1(b).

The reason can be considered to be that in addition to the volume shrinkage (increased density) caused by the phase transition to the rutile type, the interval between the TiO2 particles 101 before sintering is L0, but the rutile type after sintering is due to the volume diffusion of the particles to each other The interval between the two is shortened to L1 (L1<L0), and as a result, cracks are generated.

Therefore, SnO2 is condensed in the necked part of the sintered bonded TiO2 particles 3, the necked part is made coarse, and the bonding of the TiO2 particles 3 to each other is strengthened, and as a result, the film strength is improved.

In order to form the photocatalyst layer 2 as described above, the SnO2 sol is mixed and stirred in the TiO2 sol, coated on the substrate 1, and heat-treated (sintered) in a predetermined temperature range.

In addition, the concentration of TiO2 sol is about 4-6% (weight), adjusted to pH 11 with NH3 solution, the average primary particle size of TiO2 particles is 0.01μm (10nm), and the concentration of SnO2 sol is about 10% (weight). Use NH3 The solution was adjusted to pH 11, and the average primary particle size of SnO2 particles was 0.0035μm. The average primary particle size shown here is the crystallite size (primary particle) obtained from the half-value width of XRD (X-ray diffraction) diffraction line.

Here, because the vapor pressure of SnO2 is higher than that of TiO2, the spacing of the TiO2 particles 3 before sintering is L0 as shown in Figure 17(a), but the surface vapor pressure of the positive curvature of the titanium oxide particles 3 is high, and it has a negative curvature. The surface, that is, the surface vapor pressure of the necked part where the two titanium oxide particles 3 meet, becomes low. As a result, as shown in Fig. 17(b), SnO2, which has a higher vapor pressure than titanium oxide, enters the necked part, condenses as shown in Fig. 17(c), and sinters according to the vaporization-condensation mechanism.

Moreover, if sintering is performed according to the vaporization-condensation mechanism, the interval L2 of the TiO2 particles after sintering is approximately equal to the interval L0 before sintering, so no cracks are generated.

As mentioned above, before and after sintering, the spacing of TiO2 particles should not change substantially, and the photoactivity (R30) of the photocatalyst coating film should be 50% or more. As shown in Figure 28, it is necessary to make SnO2 to TiO2 The ratio (inner ratio) is 20-70% or more.

In addition, the compounding ratio means the weight ratio of the solid content contained in each sol. In addition, the photoactivity was evaluated by decomposition of methyl mercaptan, and the removal rate (R30) after 30 minutes of light irradiation was used as an index. In detail, in an 11L glass container, the 150 square tiles on which the photocatalyst coating film has been formed are arranged at a distance of 8 cm from the light source (BLB fluorescent lamp, 4W), and methyl mercaptan gas is injected into the container at 3-5 ppm After confirming that there is no adsorption in the dark, the fluorescent lamp is turned on, and the concentration change with time is measured by gas chromatography.

Here, R30=(X0-X30)/X0×100% where X0=initial concentration [ppm] X30=concentration after 30 minutes [ppm] In addition, the film strength is evaluated by sliding friction using plastic rubber to compare appearance changes Make an evaluation. Regarding the evaluation criteria , , , and × are the same as the above (Table 1).

In addition, FIG. 29 is a graph showing the relationship between the heat treatment temperature and the photoactivity. When an organic stabilizer is added to the TiO2 sol, although the photoactivity is reduced, the heat treatment temperature is 300-850°C. This is because the heat treatment temperature is less than 300°C to produce activity, and if it exceeds 850°C, the structure of TiO2 changes from anatase type to rutile type.

It can be seen from the above description that a sol containing titanium oxide particles and a substance with a higher vapor pressure than titanium oxide is applied to ceramic tiles, and then fired at a predetermined temperature. Since the film is formed, the intervals between the titanium oxide particles before and after sintering are approximately equal, and cracking is not easy to occur. In addition, since SnO2 or the like is condensed in the necked portion between the titanium oxide particles, the peel strength of the coating film becomes high.

In particular, the addition amount of SnO2 (internal ratio to TiO2) can reach 20-70%, which can meet the requirements of film strength and light activity. In addition, heat treatment in the range of 300°C or higher and 850°C or lower can obtain sufficient Light activity.

However, the use of gas chromatography to measure R30 requires a high cost of measuring equipment, and one equipment can only measure one sample, which is inefficient.

In addition, although it is known that supporting metals such as Pt on TiO2 improves photoactivity, in a photocatalyst thin film with such a structure, it is difficult to determine the degree of net photoactivity due to the influence of gas adsorption due to the metal.

In addition, if ceramic tiles are used as the wall surface, the activity of the photocatalyst thin film formed on the surface cannot be measured with a gas chromatograph once it has been installed.

In addition, as a method for evaluating the photoactivity without using a gas chromatograph, although a method of detecting the survival rate after light irradiation that kills bacteria by the action of a photocatalyst can be considered, it is more troublesome than the operation on a gas chromatograph, and it is more difficult to carry In the metal photocatalyst film, since the antibacterial activity of the metal itself also kills bacteria, it is not easy to determine the net light activity. Therefore, the following method for measuring the activity of the photocatalyst thin film can also be applied.

In the first method, a potassium halide aqueous solution such as potassium iodide or potassium chloride is dropped on the surface of a photocatalyst film mainly composed of TiO2 formed on the surface of the substrate, and then the dropped potassium halide aqueous solution is irradiated with ultraviolet rays for a predetermined time. The activity level of the photocatalyst film was judged from the difference between the pH of the potassium halide aqueous solution before the irradiation and the pH after the irradiation.

In the second method, on the surface of the photocatalyst film mainly composed of TiO2 formed on the surface of the substrate, a mixture of pH indicator is added to a potassium halide aqueous solution such as potassium iodide or potassium chloride, and then the mixture is irradiated. For a given time of ultraviolet light, due to the color change of the mixed liquid, the activity of the photocatalyst film can be judged.

In the third method, an activity measuring film is adhered to the surface of a photocatalyst film mainly composed of TiO2 formed on the surface of the substrate. In this state, the activity measuring film is irradiated with ultraviolet rays for a given period of time. Due to the color change of the activity measuring film, Therefore, the activity size of the photocatalyst film can be judged.

FIG. 30 illustrates the first and second activity measuring methods. The photocatalyst layer 2 mainly composed of TiO2 is formed on the surface of the substrate 1. Such a method for measuring the activity of the photocatalyst thin film can be applied.

In the first method, a potassium halide aqueous solution such as potassium iodide or potassium chloride is dripped on the surface of a photocatalyst film mainly composed of TiO2 formed on the surface of the substrate, and then the dripped potassium halide aqueous solution is irradiated with ultraviolet rays for a predetermined period of time. The difference between the pH of the potassium halide aqueous solution and the pH after irradiation determines the activity of the photocatalyst film.

In the second method, on the surface of the photocatalyst film mainly composed of TiO2 formed on the surface of the substrate, drop a mixture of potassium iodide or potassium chloride and other potassium halide aqueous solutions added with a pH indicator, and then irradiate the dropped mixture For a given time of ultraviolet rays, due to the color change of the mixed liquid, the activity of the photocatalyst film can be judged.

In the third method, an activity measuring film is adhered to the surface of a photocatalyst film mainly composed of TiO2 formed on the surface of the substrate. In this state, the activity measuring film is irradiated with ultraviolet rays for a given period of time. Due to the color change of the activity measuring film, Therefore, the activity size of the photocatalyst film can be judged.

Figure 30 illustrates the first and second activity measurement methods. A photocatalyst layer 2 mainly composed of TiO2 is formed on the surface of the substrate 1. In order to detect whether the photocatalyst layer 2 has photoactivity, the photocatalyst layer 2 A potassium halide aqueous solution 30 such as potassium iodide or potassium chloride is dropped on the surface of the slab. Then, the dropped potassium halide aqueous solution 30 is irradiated with ultraviolet light for a predetermined time with an ultraviolet lamp 40, and the difference between the pH of the potassium halide aqueous solution before the irradiation and the pH after the irradiation is The activity level of the photocatalyst layer 2 is judged.

Fig. 33 shows the relationship between the ultraviolet irradiation time and the amount of pH change. The concentration of the potassium halide aqueous solution 30 is 0.1 mol/L, the ultraviolet lamp uses a 20W BLB fluorescent lamp, the distance between the photocatalyst layer 2 and the ultraviolet lamp 40 is 20 cm, and the irradiation time is 60 minute.

It can be seen from this figure that regardless of the anatase type, the metal-supported type, or the rutile type, in the photocatalyst layer 2, the pH of the potassium halide aqueous solution 30 becomes higher when the ultraviolet irradiation time reaches 30 minutes.

In this way, the pH of the potassium halide aqueous solution 30 becomes higher due to ultraviolet irradiation, because the following oxidation reaction and reduction reaction proceed simultaneously, and OH- (hydroxide ion) is generated by the reduction reaction.

Oxidation reaction: reduction reaction: Therefore, if the pH of the potassium halide aqueous solution 30 becomes higher due to ultraviolet irradiation, it can be said that the photocatalyst layer 2 has photoactivity.

Fig. 34 shows the relationship between R30 and the amount of change in pH. In the figure, R30 is the ratio (%) of gas (methyl mercaptan, etc.) that decreases 30 minutes after ultraviolet irradiation. From this figure, it is known that R30 has a proportional correlation with the amount of pH change. That is, the amount of change in pH serves as an index of the presence or absence of photoactivity.

In the first method described above, the amount of change in pH is measured with a pH measuring instrument or a pH measuring chip, but in the second method, a mixed liquid in which a pH indicator is added to the potassium halide aqueous solution 30 is dropped on the photocatalyst layer 2. On the surface, next, the dripped mixed liquid is irradiated with ultraviolet rays for a predetermined time, and the color of the mixed liquid changes, so that the activity level of the photocatalyst layer 2 can be judged.

As a pH indicator, since the pH of the potassium halide aqueous solution 30 before ultraviolet irradiation is about 4.5, and the pH after ultraviolet irradiation is 5.5-6.5, methyl red is suitable.

In addition, in the above-mentioned first and second methods, the potassium halide aqueous solution 30 or the potassium halide aqueous solution 30 is added to the mixed solution of the pH indicator on the surface of the photocatalyst layer 2, and the liquid is dropped on each substrate The diffusion is of all kinds, and a certain liquid thickness cannot be guaranteed, and the reaction area varies with each substrate.

The method to eliminate this is the method shown in FIG. 31. In this method, after the potassium halide aqueous solution 30 or the like is dropped on the surface of the photocatalyst layer 2, the potassium halide aqueous solution 30 is pressed by a transparent plate 60 such as a glass plate, and While forming a certain thickness, prevent drying.

In addition, liquids such as the potassium halide aqueous solution 30 are based on the condition that the surface of the substrate 1 is horizontal, so it is difficult to judge the activity of the photocatalyst thin film formed on the vertical surface such as the wall surface and the ceiling.

The method to eliminate this is the method shown in FIG. 32. In this method, the activity measuring film 70 is adhered to the surface of the photocatalyst layer 2 formed on the surface of the substrate 1. In this state, the activity measuring film 70 is attached. By irradiating ultraviolet rays, the color of the activity measuring film 70 changes, so that the degree of activity of the photocatalyst layer 2 can be judged.

Here, the activity measurement membrane is obtained by drying a mixture of potassium halide aqueous solutions such as potassium iodide or potassium chloride and a pH indicator on an organic binder to form a film.

Next, the porosity of the photocatalyst layer 2 is examined. Here, the porosity is called open porosity, and the porosity is 10% or more and 40% or less, preferably 10% or more and 30% or less.

In this case, the crystal particle diameter of the photocatalyst particles may be 0.1 μm or less, preferably 0.04 μm or less. Since the smaller the crystal grain size, the larger the effective reaction area per unit volume, the film thickness of the photocatalyst layer can be about 0.1 μm. In addition, the photocatalyst particles are sintered in a solid phase with each other to form a necked part, so that when the strength of the layer is increased, the crystal grain size is increased to 0.1 μm or more, because the effective area of reaction per unit volume is reduced, so The film thickness is 0.5 μm or more, preferably 0.6 or more.

In addition, between the photocatalyst particles constituting the photocatalyst layer formed on the surface of the substrate, particles having a crystal particle diameter of 0.01 μm or less, preferably 0.008 μm or less may be added. By adding such particles, the gaps between the photocatalyst particles can be filled, and the particle filling rate and surface smoothness can be improved, thereby increasing the film strength against shear stress. As the surface smoothness is improved, it is possible to make contamination difficult to adhere. Although the porosity is reduced at this time, the buried porosity is below the crystal grain size of 0.01μm, preferably 0.008μm or less. The size of the particles is larger than the size of the gas (several ), so it is not Affect deodorization.

Here, the type of particles with a crystal particle size of 0.01 μm or less, preferably 0.008 μm or less, basically any type is acceptable. However, in addition to filling the gaps of the photocatalyst particles, there is a risk of covering a part of the surface, so it does not damage the light. Catalytically active oxide semiconductors such as TiO2, SnO2, ZnO, SrTiO3, Fe2O3, Bi2O3, WO3, or metals such as Ag and Cu are ideal. In addition, the method of adding particles with a crystal particle size of 0.01 μm or less, preferably 0.008 μm or less, can be basically any method. For example, such ultra-fine particles can be generated by hydrothermal treatment, dispersed into a sol with a suitable dispersion, and the sol can be coated on the photocatalyst layer by spraying, and the sol can be heat treated at a low temperature where no particle growth occurs to make the organic The dispersant evaporates. In addition, a metal alkoxide and an organic metal salt may be coated on the photocatalyst layer, and heat treatment may be performed to evaporate the diluent and organic components.

In addition, metal particles smaller than the pore diameter of the photocatalyst layer formed on the surface of the substrate may be fixed. By fixing the metal particles, using the electron trapping effect, the photocatalytic activity is improved compared with the case of a separate photocatalyst layer, and the deodorization becomes better.

Here, the type of metal particles can be anything that can trap electrons. For example, Cu, Ag, Pt, etc. can be mentioned.

The average particle size of the metal particles must be smaller than the average pore size on the surface of the photocatalyst layer. If the average pore size of the photocatalyst layer surface is 10% or more, and 40% or less of the sample is observed with an electron microscope, the diameter is approximately the same as that of the photocatalyst particles, so it is required to be smaller than the diameter of the photocatalyst particles. Ideally, it can be smaller than the photocatalyst particle diameter of the starting material. The starting material of the photocatalyst layer is generally 0.05 μm or less, so it may be 0.05 μm or less.

Specific examples of porosity are listed below.

Example 28: On a 15cm square ceramic tile substrate, the ammoniolytic gel suspension of TiO2 sol with a crystal particle size of 0.01μm was applied by spraying method, and the amount of coating was changed, and it was calcined at a temperature above 700°C and below 900°C to form For the photocatalyst layer, the obtained samples were evaluated for the crystal size of the anatase-type TiO2 particles, the open porosity of the layer surface, deodorization, abrasion resistance, and peeling resistance.

The evaluation of deodorization was evaluated by measuring R30 (L). The so-called R30 (L) is the removal rate after light irradiation. Specifically, in an 11-liter glass container, the surface on which the sample photocatalyst film is formed is arranged at a distance of 8 cm from the light source (BLB fluorescent lamp, 4W), so that The initial concentration of the methyl mercaptan gas was 3 ppm, it was injected into the container, and the concentration change at 30 minutes of irradiation was measured.

For the evaluation of abrasion resistance, the sliding friction of a plastic rubber was used to compare the changes in appearance and evaluate. The evaluation index is the same as the above, and is shown below.

: No change to 40 times of reciprocation : Scratches in 10 or more and 40 times of sliding, and peeling of the photocatalyst layer (TiO2 film) : Scratches in 5 or more and 10 times of sliding, photocatalyst Layer (TiO2 film) peeled x: Scratches occurred after 5 times or less sliding, and the photocatalyst layer (TiO2 film) peeled off.

The peel resistance test is a test that is more severe than the abrasion resistance test. Instead of the plastic rubber, a sanded rubber (LION TYPEWRITERERASER 502) with greater shear is used. The specific evaluation method was performed by rubbing the surface of the sample 20 times with an equal force with a sand rubber, and visually comparing it with the standard sample in the state of containing scratches. The evaluation criteria are expressed as follows.

: No change at all : A slight change is confirmed by light addition and subtraction : A slight change is confirmed ×: The change can be confirmed at a glance The results are shown in Figs. 35-37.

Fig. 35 shows the relationship between the porosity and the deodorization and abrasion resistance when the thickness of the photocatalyst film is 0.8 μm. The deodorant property increases with the increase in porosity, exceeding 50% at 10%, and reaching over 80% at 30%. On the contrary, the abrasion resistance to 30% is , but 40% is , and if it exceeds this, it is or ×. From the above facts, it can be seen that in order to produce a member with both deodorization and abrasion resistance, the porosity of the photocatalyst film must be 10% or more and 40% or less, preferably 10% or more and 30% or less.

Fig. 36 shows the relationship between the deodorization property and the film thickness when the crystal size of the photocatalyst particles constituting the photocatalyst thin film with a porosity of 20-30% changes. When the crystal grain size is 0.1 μm, the relationship between R30 (L) and the film thickness is seen, and if it becomes thinner, the deodorant property decreases. However, the relationship with the film thickness is not seen at 0.04 μm or less, and even if the film thickness is 0.1 μm, good deodorant properties are shown. From the above facts, it can be seen that setting the crystal grain size of the photocatalyst particles to 0.1 μm or less, preferably 0.04 μm or less, can make the photocatalyst thin film thinner to a film thickness of about 0.1 μm and ensure good deodorization.

Fig. 37 shows the relationship between deodorization and peeling resistance and film thickness when the photocatalyst particles constituting the photocatalyst thin film with a porosity of 20-30% and the bonding state are both changed. If the required value of mechanical strength rises to the level of the peel resistance test, the sample without a necked part will be or ×. In addition, in order to form a mechanically sufficient necking bond by solid phase sintering of the photocatalyst particles, it is not enough for the photocatalyst particles to grow to 0.04 μm, and it is necessary to grow to about 0.1 μm. However, if the photocatalyst particles grow to about 0.1μm, the deodorization is already related to the film thickness. The thicker the film, the more deodorization increases. Specifically, when the film thickness is 0.5μm, R30(L) exceeds 50% , Reaching more than 80% at 0.6μm. From the above results, it can be seen that solid-phase sintering of the photocatalyst particles with each other, formation of necked parts between the particles, and growth of the particles to a crystal grain size of 0.1 μm or more can sufficiently improve the film strength. In this case, by increasing the crystal grain size to 0.1 μm or more, since the effective reaction area per unit volume is reduced, the film thickness must be 0.5 μm or more, preferably 0.6 μm or more.

In Example 29, a 15 cm square ceramic tile substrate was coated with an ammoniolytic colloidal suspension of TiO2 sol with a crystal particle size of 0.01 μm by spraying, and then calcined at 750° C. to form a photocatalyst film. The porosity of the TiO2 film at this stage is 45%, and the crystal grain size of the TiO2 particles is 0.02 μm. SnO2 sols with different crystal particle diameters were applied by spraying method respectively, and dried at 110°C to obtain samples. Deodorization and abrasion resistance were evaluated for the obtained samples.

The results are shown in Figure 38. Regarding the deodorization property, the crystal particle size of the SnO2 sol changed from 0.0035 μm to 0.01 μm with little change, showing good results. Contrary to this, the effect of adding 30% by weight or more of abrasion resistance varies with the crystal grain size of the SnO2 sol. That is, in the case of adding particles of 0.008 μm or less, it increased to or , but the addition effect was not seen at 0.01 μm.

From the above results, it can be seen that the abrasion resistance can be improved by adding particles with a crystal particle size of 0.01 μm or less, preferably 0.008 μm or less, between the photocatalyst particles.

Example 30: On a 15cm square ceramic tile substrate, the ammoniolytic gel suspension with a TiO2 sol crystal particle size of 0.01μm was applied by spraying method and varying the amount of coating, and it was fired at 850°C to form a light film with a thickness of 0.2μm. Catalyst film. Next, a copper acetate aqueous solution was coated on the photocatalyst film by a coating method, and then photoreduction was performed (light source 20W BLB lamp, distance from the light source to the sample was 10 cm, and the irradiation time was 10 seconds) to obtain a sample. The amount of copper supported at this time is 2 μg/cm2, and its particle size is several nm-10 nm. In addition, the crystal grain size of the photocatalyst particles is 0.1 μm. The deodorant property and abrasion resistance were evaluated for the obtained sample.

As a result, R30 (L) was 80%, and the abrasion resistance was . Therefore, compared with FIG. 36, R30(L) rises from 18% to 89% due to the support of copper.

As can be seen from the above description, by forming a photocatalyst film with a porosity of 10% or more and 40% or less, preferably 10% or more and 30% or less, on the surface of the substrate, a member with both deodorization and abrasion resistance can be provided. .

Next, an example in which the gap formed on the photocatalyst layer is filled with particles smaller than the gap will be described. The gap in this embodiment refers to both the gap between the separated particles and the recessed portion of the necked part.

In addition, if the photocatalyst layer is dense, it is excellent in terms of film strength and resistance to contamination. However, because the temperature at which the photocatalyst layer is formed generally increases and the material of the base material is limited, if the particles are filled in the subsequent process If desired in the gap, the porosity of the photocatalyst layer before the addition of gap particles can be 10% or more. In addition, a film with a porosity of 10% or more has excellent deodorization, so by adjusting the filling amount, it is possible to provide a multifunctional material excellent in both anti-law property and deodorization.

The particles in the gaps that are smaller than the gaps to be filled are preferably composed of inorganic crystalline raw materials, and more preferably may be derived from oxide semiconductors such as TiO2, SnO2, ZnO, SrTiO3, Fe2O3, Bi2O3, WO3, etc., which have photocatalytic activity.

The size of particles smaller than the gap can be substantially smaller than the average value of the generated pores. By reducing the gap and reducing the particles adhering to the surface of the particles with the photocatalytic function, the surface smoothness and the surface defects are improved, and the adhesion of pollution is not easy and the film strength is improved. Specifically, it can be 0.01 μm or less, preferably 0.008 Small particles below μm. However, when the TiO2 film is anatase type and is heat-treated below 850°C and fixed on the substrate, observation with an electron microscope shows that the average pore size and the diameter of the TiO2 particles are approximately equal, and the diameter is smaller than that of the TiO2 particles. . The starting material for the photocatalytically active TiO2 thin film usually uses a material of 0.05 μm or less, so it can be a material of 0.05 μm or less.

Here, the surface porosity of the layer with the photocatalytic function formed by filling the gaps with particles is 20% or less, making it more difficult for contamination to adhere. It is more desirable that the maximum width of the pores is 0.04 μm or less.

Here, the so-called porosity is the open porosity on the surface of the substrate, and the maximum width of the open pores is the maximum distance between two adjacent particles (average value + 3 x standard deviation) among the particles with photocatalytic function that constitute the surface of the substrate ).

In addition, if a layer with a porosity of about 10% of the layer having a photocatalytic function before the particles are filled in the gap is used, although the porosity is reduced to 10% or less, the diameter of the pores buried here is a crystal grain size of 0.01 The entry size of particles below μm is larger than the size of the gas (number Å), so it does not affect the deodorization performance and can maintain the same deodorization properties as a pre-made TiO2 film with a porosity of 10% or more.

In addition, the layer with the formed photocatalytic function is mainly crystalline photocatalyst particles, so that the dirt does not adhere in a firm adhesion form of the glass adhesion type, and at the same time, even if the scale adheres, it is relatively easy to wipe off. In addition, when the water is recycled, there is an effect that it is not easy to produce algae.

Here, the so-called crystalline photocatalyst particles means that when the photocatalyst particles removed from the member are subjected to powder X-ray diffraction under the conditions of 50KV and 300mA, the maximum peak of the crystal (for example, in TiO2 particles, anatase type 2θ= 25.3°, rutile 2θ=27.4°) crystallized into photocatalyst particles to the extent detected.

As a method of filling particles in the above-mentioned gaps, alkoxylates, organometallic salts, sulfates, etc. are used, and they are applied by coating, drying, and heat treatment. For example, the process of using a metal alkoxide is to mix the metal alkoxide with a suitable diluent and hydrochloric acid and coat the solution on the outermost surface of the photocatalyst layer, and then perform a drying heat treatment. Here, the diluent is preferably alcohols such as ethanol, propanol, and methanol, but it is not limited to these. Can be as free as possible. If it contains water, the hydrolysis of the metal alkoxide is explosively promoted, which becomes a cause of cracks. In addition, hydrochloric acid is added to prevent cracking during drying and heat treatment. The coating method of the metal alkoxide is usually carried out by the curtain coating method. But it is not limited to this. Rain coating is best carried out in dry air. If it is applied in normal air (atmosphere), the moisture in the air promotes hydrolysis, making it difficult to control the film thickness. It can be applied once or several times. This is determined by the fillability of the photocatalyst layer before coating. After that, it is placed in dry air for a few minutes to form a film in which the gaps of the photocatalyst layer are filled with particles.

Here, if the filler particles are preliminarily made of the same material as the layer before coating the filler particles, the thermal expansion coefficient is also the same, and it is desirable because a film with excellent mechanical strength can be formed.

As a specific example, an example of using titanium alkoxide will be described again. In the process of re-coating the titanium alkoxide on the surface of the photocatalyst layer and performing the drying heat treatment, the coating amount of the titanium alkoxide per time converted into TiO2 is 10 μg/cm2 or more and 100 μg/cm2 or less. If the amount is too small, the number of coatings must be increased, so the efficiency is low. On the contrary, if the amount is too large, the film thickness per coating is too thick, and cracks occur during drying and heat treatment.

In the above drying heat treatment process, the heat treatment temperature is above 400°C, below 800°C, and below 400°C, amorphous TiO2 does not crystallize into anatase TiO2, and rapid particle growth occurs at 800°C, so the photoactivity is reduced.

In addition, the amount of hydrochloric acid should be 1% by weight or more and 10% by weight or less with respect to the titanium alkoxide in the coating liquid. Below 1% by weight, the crack prevention effect is insufficient. If it exceeds 10% by weight, hydrochloric acid is usually a 36% aqueous solution with a large amount of water, so hydrolysis is excessively promoted and cracks are formed. When the amount of hydrochloric acid is large, the diluent may be large. Because the diluent inhibits hydrolysis. The ratio is hydrochloric acid (except moisture): diluent can be about 1:100-1:1000.

Furthermore, a layer with a photocatalytic function is formed, and the gap formed on the surface of the layer is filled with particles smaller than the gap. Cu, Ag, Zn, Fe, Co, Ni, Pd, At least one metal in Pt. Due to such a structure, the above-mentioned metal preliminarily occupies a highly adsorbable site in the layer having a photocatalytic function, and alkali metals, calcium, etc. in the dust component adhere to the site, and the photocatalytic activity is not lost. Therefore, it is difficult to impair the antibacterial effect of the photocatalyst, and it is also possible to prevent contamination due to adhesion of fungi. In addition, if Ag, Cu, and Zn are used as the aforementioned metals, since these metals themselves have antibacterial properties, it is possible to more effectively prevent the adhesion of fungi. The electron trapping effect of these metals is also used to improve the photoactivity of the photocatalyst layer.

The size of the metal to be fixed is so large that it preliminarily occupies the highly adsorbed portion of the photocatalyst layer, and it can be small to maintain high activity. From this point of view, it is better to be several nm-10 nm.

Here, as a method for fixing the above-mentioned metal, photoreduction, heat treatment, sputtering, chemical vapor deposition, etc. can be used. However, it never requires large-scale equipment, is a relatively simple method and can be firmly fixed. , The photoreduction method is preferred. The process of photoreduction is to coat an aqueous solution containing at least one metal ion among Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt, and then irradiate light containing ultraviolet rays. In the aqueous solution containing at least one metal ion among Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt, copper acetate, silver nitrate, copper carbonate, copper sulfate, cuprous chloride, copper oxide , Chloroplatinate, palladium chloride, nickel chloride, zinc nitrate, cobalt chloride, ferrous chloride, ferric chloride, etc. The coating method of these metal salts can basically be any of the above-mentioned methods, but the spraying method or the dipping method is relatively simple. Compared with the two, the spraying method is more ideal in terms of the small amount of solution used, the uniform coating, the easy control of the film thickness, and the ability to not adhere to the back as needed. When irradiating a light source containing ultraviolet light, any light source capable of irradiating ultraviolet light may be sufficient. Specifically, any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, and a fluorescent lamp may be used. The ideal method of irradiating ultraviolet light is to arrange the sample so that the light is irradiated perpendicularly to the irradiated surface, because the irradiation rate is the best. The irradiation time is preferably about 10 seconds to 10 minutes. If the irradiation time is too short, the above-mentioned metals will not sufficiently adhere to the highly absorbing parts of the photocatalyst layer, so that alkali metals, calcium, etc. in the dust component will adhere, which will cause the loss of photocatalytic activity. If the time is too long, the above-mentioned metals will adhere excessively. , It is difficult for light to reach the photocatalyst layer sufficiently, thus reducing the photocatalytic activity. The distance between the sample and the light source is preferably 1 cm-30 cm. If the distance is too short, the light cannot irradiate the entire sample surface with substantially uniform illuminance, and the adhesion deviation of the above-mentioned metal is likely to occur. If the distance is too long, the illuminance of the light decreases inversely proportional to the square of the distance, and it is difficult to firmly adhere the metal.

A specific example of filling the gap formed on the photocatalyst layer with particles smaller than the gap will be given below.

In Example 31, a 15 cm square ceramic tile substrate was spray-coated with an ammoniolytic colloidal suspension of TiO2 sol with a crystal particle size of 0.01 μm and calcined at 750°C to form an anatase TiO2 film. The porosity of the TiO2 film at this stage is 45%, and the crystal size of the TiO2 particles is 0.02 μm. Then, SnO2 sols with different crystal particle diameters were coated on it by spraying method, and dried at 110°C to obtain samples. The obtained samples were evaluated for odor resistance, abrasion resistance, and difficulty in adhesion of contamination.

The deodorant property was evaluated by measuring R30 (L).

Regarding the wear resistance, a plastic rubber was used for sliding friction, and the changes in the appearance were compared for evaluation. The evaluation index is as follows.

: No change to 40 times of reciprocation : Scratches in 10 times or more and 40 times or less, TiO2 layer peeling : Scratches in 5 times or more and 10 times or less, TiO2 layer peeling ×: In 5 There were scratches on the sliding below the second time, and the TiO2 layer was peeled off.

Regarding the evaluation of the difficulty of stain adhesion, a black thick universal pen was used to draw a line on the surface of the substrate, and the stain was evaluated by wiping off the pen line with ethanol after drying. The evaluation index is shown.

: The trace disappeared completely.

: A trace remains slightly.

: Grayish-green traces remain.

×: A black mark remains.

The results are shown in Figure 39-Figure 46.

Figure 39 shows the difficulty of contamination adhesion relative to the amount of SnO2 added. In this figure, the addition amount of SnO2 is expressed by the weight relative to the amount of TiO2 and SnO2 and the weight ratio of SnO2. When 30% or more of SnO2 is added, the degree of adhesion of pollution increases rapidly. The reason is explained as the following three points. The first is that by adding 30% or more of SnO2, the porosity is reduced to 20% or less (Figure 40). The second is that due to the addition of SnO2, the pores with large pore diameters are reduced. Fig. 41 shows the maximum width of the open pores relative to the addition amount of SnO2. When the addition amount of SnO2 is 30% or more, it becomes a relatively small 0.04 μm. The third reason is that the addition of SnO2 improves the surface finish, which also has an impact.

Fig. 42 shows the deodorant property and abrasion resistance relative to the amount of SnO2 added.

Regarding the deodorant properties, even if the crystal particle size of the SnO2 sol is changed from 0.0035 μm to 0.01 μm, it hardly changes, showing good results. In addition, when the amount of SnO2 is 50% or less, R30 shows good results of 80% or more. Comparing the relationship between the addition amount of SnO2 and the porosity in FIG. 39, it can be seen that when the addition amount of SnO2 is 40% or more and 50% or less, although the porosity is 10% or less, good deodorant properties are formed. The result of this tendency is different from the result of the relationship between the porosity and the deodorant property (FIG. 35) in the case where the particles for filling the gap are not added. The reason can be considered as follows. In this case, although the porosity is reduced to less than 10%, compared with Fig. 41, pores of about 0.02μm remain, and the crystal grain size of the particles that fill the gap is 0.0035μm compared with the size of the gas (number ) Because the particles do not grow up under this condition, the passage that does not generate gas is blocked.

Regarding abrasion resistance, the effect when the addition amount of SnO2 is 30% or more differs depending on the crystal grain size of the SnO2 sol. That is, when particles of 0.008 μm or less are added, it increases to or , but the addition effect is not seen at 0.01 μm.

It can be seen from this experiment that (1) a TiO2 film is formed on the substrate, and if particles (SnO2 sol) smaller than the gap are added to the gaps formed on the surface of the film, it is difficult for contamination to adhere.

(2) If the addition amount of SnO2 is 30% by weight or more relative to the total weight of TiO2 and SnO2, contamination will not easily adhere and the wear resistance will also be improved.

(3) If the addition amount of SnO2 is 50% by weight or less with respect to the total weight of TiO2 and SnO2, the deodorant property can still be maintained well.

(4) If the porosity is 20% or less and the maximum width of the open pores is 0.04 μm or less, it will be difficult for contamination to adhere.

In Example 32, anatase-type TiO2-forming material was installed on the side of the urinal operator where the light was not visible, and the two-week field test was performed to compare with the material that does not form a normal anatase-type TiO2 film. The results are both Co-attach to yellow dirt caused by fungus, kidney, bladder and other stones. However, in contrast to the dirt on the grate of a normal toilet that does not come off by wiping, when a material forming an anatase TiO2 film is used on the side part, the yellow color of the dirt will almost disappear significantly if it is wiped.

Due to the lack of light irradiation on the side of the grate, the result is explained as the lack of the photocatalytic effect of the anatase TiO2 film, rather than the formation of a crystalline anatase TiO2 film on the surface where dirt is difficult to adhere firmly.

In Example 33, SiO2-Al2O3-Na/K2O glass frit was coated on the surface of a 15 cm square ceramic tile, and then sprayed on the surface of the ceramic tile with an ammoniolytic gel suspension of TiO2 sol with a crystal particle size of 0.01 μm. It was fired at 750°C for 2 hours, and the TiO2 film was made into three types: 0.2 μm, 0.4 μm, and 0.8 μm according to the film thickness of the TiO2 thin film. The porosity of the TiO2 film at this stage is 45%, and the crystal grain size of the TiO2 particles is 0.02 μm. On the cooled sample, dry air is used as a carrier gas, and a 10:1:400 (weight ratio) mixture of titanium tetraethoxide, 36% hydrochloric acid and ethanol is coated by a shower method, and then dried. The coating amount is 40-50μg/cm2 in terms of TiO2. After that, firing was performed at 500°C for 10 minutes. Perform 1-5 times of titanium alkoxide coating process. The obtained samples were evaluated for their deodorization, antibacterial properties, abrasion resistance, and adhesion difficulty of contamination.

Regarding the antibacterial properties, the test was conducted with Escherichia coli (Escherichia coli W3110 strain). Drop 0.15ml (1-50000CFU) of bacterial liquid on the top surface of the multifunctional material pre-sterilized with 70% ethanol, and place it on a glass plate (100×100) to closely adhere to the top surface of the substrate to prepare a sample. After irradiating with a white light (3500 Lux) for 30 minutes, wipe the bacterial solution of the irradiated sample with sterile gauze and recover it in physiological saline to obtain the bacterial survival rate. About the evaluation index +++, ++, + ,-Same as above.

Under any of the above conditions, the deodorant R30 (L) is 80% or more, and the antibacterial property is +++.

Regarding the difficulty of adhesion of dirt (Figure 44) and wear resistance (Figure 45), it depends on the number of times the titanium alkoxide is applied and the thickness of the TiO2 film. If the titanium alkoxide is applied more frequently, the difficulty of adhesion of contamination and the abrasion resistance increase. In addition, the thinner the TiO2 film thickness, the fewer the number of times the titanium alkoxide can be applied to increase the adhesion difficulty and wear resistance of contamination. One of the reasons for this is considered to be that the porosity of the surface of the TiO2 layer formed by coating titanium alkoxide is reduced. FIG. 46 shows the relationship between the porosity of the surface of the TiO2 layer, the number of times the titanium alkoxide is applied, and the thickness of the TiO2 film. The more times the titanium alkoxide is applied, the more the porosity on the surface of the TiO2 layer decreases, and the thinner the TiO2 film thickness is. With the same titanium alkoxide coating times, the more the porosity on the surface of the TiO2 layer decreases. Corresponds well to the relationship between the number of times of titanium alkoxide coating, the TiO2 film thickness, the adhesion difficulty of contamination, and the wear resistance. Particularly in terms of the difficulty of adhesion of contamination, it is the same as in the case of Example 31, and the porosity is 30% or less.

Example 34 SiO2-Al2O3-Na/K2O glass frit was coated on the surface of a 15cm square ceramic tile, and then on the surface, the ammoniolytic gel suspension of TiO2 sol with a crystal particle size of 0.01 μm was sprayed on the surface Calcination is carried out at 750°C for 2 hours, the film thickness of the TiO2 thin film at this stage is 0.4μm, the porosity is 45%, and the crystal grain size of the TiO2 particles is 0.02μm. On the above-mentioned sample that has been cooled, use dry air as a carrier gas to coat with a mixture of 10:1:400 (weight ratio) titanium tetraethoxide and 36% hydrochloric acid and ethanol, and then dry it. . The coating amount is 40-50μg/cm2 in terms of TiO2. It was then fired at 500°C for 10 minutes. The titanium alkoxide coating process was repeated three times. After that, a 1% (weight) silver nitrate aqueous solution was applied to the sample to perform photoreduction (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, and the irradiation time was 30 seconds) to obtain a sample. Here, the amount of silver supported on the surface of the sample is 0.7 μg/cm 2, and the particle size of silver is about 40 nm on average. The antibacterial properties and antibacterial properties after long-term use were measured on the obtained samples.

The antibacterial properties after long-term use were tested as follows. First, clean the surface of the obtained sample well with ethanol, etc., and dry it at 50°C. Then pour the bathtub water collected in the public bath into a sterilized beaker, immerse the sample in it, and leave it for one month. Then take out the sample, wash it with ethanol or the like, and sterilize the outermost surface of the multifunctional material with 70% ethanol. Next, drop 0.15ml (1-50000 CFU) of Escherichiacoli (Escherichiacoli W3110 strain) bacterial liquid on the top surface of the above sample, place it on a glass plate (100×100), and paste it on the top surface of the substrate. Tight, as a sample.

After irradiating with a white light (3500 Lux) for 30 minutes, the bacterial solution of the irradiated sample was wiped with sterile gauze and recovered in 10 ml of physiological saline, and the survival rate of the bacteria was determined as an evaluation index. The evaluation index is the same as the antibacterial test of Example 3.

For comparison, the sample used in Example 33 was also tested.

As a result, for the initial antibacterial properties, the samples produced in this example and the samples produced in Example 33 are all +++, but there is a difference between the two in terms of antibacterial properties after one month. . That is, the antibacterial property of the sample prepared in Example 33 deteriorated to +, while the sample prepared in this example showed a value of +++ that did not change from the initial stage. This can be explained as the fact that silver occupies the highly adsorptive part on the surface of the TiO2 layer, so it prevents the adhesion of dirt and the like in the highly adsorptive part during use.

From the above description, it can be seen that a layer with a photocatalytic function is formed on the surface of the substrate. Since the gaps formed on the surface of the layer are filled with particles smaller than the gaps, the number and size of gaps existing on the surface are higher than those of conventional photocatalyst thin films. It is small, and because of its good surface smoothness, it maintains deodorization while increasing the strength of the membrane, and it can make it difficult for macromolecules, dirt, fungi and the like that constitute dirt components to adhere.

The following describes the use of a raw material with a low melting point such as soda lime glass as a substrate. That is, when a photocatalyst film is formed on the surface of a low melting point substrate, the substrate has already begun to soften at the temperature at which the catalyst film is formed, and the formed photocatalyst film has been buried in the substrate, so light cannot reach the photocatalyst layer. , Resulting in undesirable situations where the photocatalytic function cannot be exerted.

Therefore, in such a case, the photocatalyst particles are fixed on the substrate by a layer having a higher melting point than the substrate such as a SiO2 layer. Specific embodiments are described as follows.

Example 35 Before coating titanium oxide on soda lime glass, silica was coated on the surface of soda lime glass.

A 10 cm square soda lime glass was coated with silica by the following method. First, mix tetraethoxysilane, 36% hydrochloric acid, pure water and ethanol at 6:2:6:86 (weight ratio). Because of heat at this time, it was left for about 1 hour. It is coated on the soda lime glass by airflow coating.

Next, a coating solution is prepared. Titanium tetraethoxide and ethanol were mixed at a ratio of 1:9 (weight ratio) to form a solution, and 10% (weight) of 36% hydrochloric acid was added to the titanium tetraethoxide to prepare a coating solution. Here, the amount of 36% hydrochloric acid added can be 1% by weight or more, 30% by weight or less, preferably 5% by weight or more, and 20% by weight or less relative to titanium tetraethoxide. . By adding an appropriate amount of hydrochloric acid, cracks can be prevented during the subsequent drying and roasting process. In other words, if the amount of hydrochloric acid is too small, the effect of preventing cracks cannot be fully achieved. If the amount of hydrochloric acid is too much, the increase in the amount of water contained in the hydrochloric acid reagent accelerates the hydrolysis of titanium tetraethoxide and it is difficult to form a homogeneous coating film. .

Next, the solution was coated on the surface of the soda lime glass substrate in dry air by a curtain coating method. Here, the term "dry air does not mean air containing no moisture at all, but means air with less moisture than normal air. At this time, if the coating is carried out in ordinary air without drying treatment, the moisture in the air accelerates the hydrolysis of titanium tetraethoxide, and the amount of coating film at one time is too large, and cracks are likely to occur in the subsequent drying and firing processes. In addition, due to accelerated hydrolysis, it is difficult to control the amount of coating film. In order to prevent cracks, it is desirable that the primary supported amount of titanium oxide is 100 μg/cm2 or less. This time, the primary supported amount of titanium oxide is 45 μg/cm2.

Then, a drying treatment is performed in dry air for 1-10 minutes to form a titanium oxide film. Using the process up to this point, titanium oxide was obtained according to the following principle. Here, the starting material is titanium tetraethoxide, which is one of the titanium alkoxides (even if other titanium alkoxides are used in principle, they can be produced.

The top surface of the substrate is tightly attached as a sample. After irradiating with a white lamp (5200 Lux) for 30 minutes, wipe the irradiated sample and the bacterial solution of the sample kept under the shielded condition with sterile gauze, and recover it in 10ml of physiological saline to obtain the survival rate of the bacteria as Evaluation index. The evaluation indicators +++, ++, +,-are the same as above.

The firing temperature was 300°C, and the sliding test showed a good result of , but R30 (L) was 0%. It is considered that this is caused by not crystallizing amorphous titanium oxide into anatase type.

At 400°C, where the anatase type can be confirmed by X-ray synthesis experiments, the sliding test also shows good results of , but R30(L) is also increased to about 60%. And the antibacterial property is also +. In addition, even at 500°C, the sliding test also showed a good result of , but R30 (L) also increased to about 60%.

When the temperature is increased, the soda lime glass of the base material is deformed at 550°C, and the multifunctional material cannot be manufactured.

Example 36 In order to further improve the photocatalytic properties of the sample obtained in Example 35, metal particles are supported. The photocatalyst undergoes a reduction reaction at the same time as the oxidation reaction. If the reduction reaction is not carried out, the electrons are not consumed, the particles are charged, and the oxidation reaction cannot proceed. It is considered that this is the reason why R30(L) is limited to 60% in Example 1. In order to prevent this, metal particles are supported on titanium oxide particles to allow electrons to escape and to prevent charging.

The metal particles are supported by the following method. Spread the metal salt solution on the photocatalyst, and irradiate it with a 20W BLB fluorescent lamp for 1 minute at a distance of 20 cm. In the metal salt solution, a 1% (weight) ethanol solution of copper acetate is used when supporting copper, and a 1% (weight) ethanol/water=1/1 mixed solution of silver nitrate is used when supporting silver. After irradiation, wash and dry. The metal salt solution is not used here, but the ethanol-containing solution is used, which makes the metal salt solution have good wettability to the sample.

The samples thus obtained were evaluated for deodorization, abrasion resistance, and antibacterial properties. The results are shown in Table 20. In addition, only samples obtained at a firing temperature of 500°C were used. (Table 20)<

>The sliding test showed good results of . And R30(L) has increased dramatically to 98%. The antibacterial property is also +++.

Comparative Example 37 was carried out in the same manner except that silica coating was not applied in Example 35. That is, titanium oxide is coated on a 10cm square soda lime glass. The results are shown in Table 21. (Table 21)

It can be seen from Table 21 that the sliding test at 300°C, 400°C, and 500°C all show good results of , but R30(L) even if the process from tetraethoxy titanium coating to firing is repeated 10 times, it is still 0%, and the antibacterial properties are all -.

At 300°C, R30(L) is inferior, which is considered to be because titanium oxide has not crystallized from amorphous titanium oxide to anatase type.

On the other hand, at 400°C and 500°C, the amorphous titanium oxide has been crystallized to the anatase type, and the inferiority of R30(L) cannot be explained for the above reasons. It is considered that this is because the soda lime glass of the base material is softened, and the titanium oxide film is buried in the glass.

From the above description, it can be seen that even with a relatively low melting point substrate, a multifunctional material with deodorant and antibacterial properties can be manufactured by using a high melting point layer between the photocatalyst layer and the substrate.

An example suitable for maintaining the photocatalytic effect on a surface of plastic or the like with poor heat resistance will be described below.

The substrate is not limited to plastics, ceramics, ceramics, glass, or composites thereof that have poor heat resistance.

The shape of the base material can be any shape. It can be a simple shape such as a ball, a cylinder, a cylinder, a tile, a wall material, a floor plate, etc., and it can also be a sanitary ceramic or a face wash. Tables, bathtubs, sinks, toilet seats and other complex shapes, and the surface of the substrate can be porous or dense.

The type of the binder may be thermoplastic materials such as inorganic glass, thermoplastic resin, and solder, or thermosetting materials such as fluororesin, silicone resin, and silicone resin. However, in view of the need to irradiate light containing ultraviolet rays in the subsequent process, a photo-corrosive material is preferable. In addition, only in the case of heat treatment at 300°C or less, from the viewpoint of particularly high usefulness of the present application, it is desirable that the thermoplastic material is a material that can be softened at 300°C or less, and the thermosetting material is a material that can be cured at 300°C or less. Examples of materials that satisfy these conditions include boric acid-based glass, solder, and acrylic resins as thermoplastic materials, and fluororesins, siloxane resins, and silicone resins as thermosetting materials.

As a method of coating these adhesive layers on the substrate, there are spraying method, roll coating method, dip coating method, etc. when using thermoplastic materials. Any one of these methods can be used, or other methods can be used. Other methods. In addition, the composition of the binder does not necessarily have to be the same as the composition of the binder when the component is completed. For example, when the binder is composed of inorganic vitreous, the coating material may be a suspension of an inorganic vitreous composition such as granules, glass frit, agglomerates, powder, etc., or a mixture containing constituent metal component salts. When the binder is a resin, a resin solution of this composition can be used, or other methods other than this can be used.

Before coating the photocatalyst particles on the adhesive layer, the applied adhesive layer may be dried to evaporate water and the like. The drying method at this time includes a method of leaving at room temperature, a method of heating together with the base material, and the like.

In addition, before coating the photocatalyst particles on the adhesive layer, heat treatment has been applied at a temperature lower than the softening temperature of the base material, the adhesive layer becomes the adhesive composition when the component is completed and the softening temperature is applied. Adhesive layer. According to this method, the formation of the photocatalyst particles on the adhesive layer is smoother than that of the previous adhesive layer. Therefore, even if a small amount of the photocatalyst particles are applied, a sufficient effect can be exerted.

When using a thermosetting material, the method of mixing the binder and the curing agent and coating it on the substrate, for example, according to the method of adding a diluent to the thermosetting resin, and then adding the curing agent to the mixture. The method on the surface of the substrate.

It is desirable that the viscosity increase value is 105 poise or more and 1075 poise or less. After the high viscosity value of 105 poise or more is formed, the photocatalyst particles are coated, so that the photocatalyst particles may be buried in a state that is not completely buried in the adhesive layer. In addition, the formation of 1075 poise or less, the photocatalyst particle layer At least a part of the lowermost layer is buried in the adhesive layer.

The method of coating the above-mentioned photocatalyst particles on the surface of the adhesive layer is basically carried out in accordance with the method of applying a material obtained by appropriately treating the starting material on the adhesive layer.

As the starting material, although a sol suspension of the photocatalyst composition is desired, a fine particle suspension of other photocatalyst compositions may also be used. In either case, in order to form a uniform coating film, it is necessary to add a surface treatment agent such as a dispersant so that the photocatalyst composition in the suspension does not aggregate. As the coating on the adhesive layer, there are spray coating, roll coating, dip coating, etc., but any of these methods may be used, or other methods other than these may be used.

The embedding thickness of the photocatalyst layer into the adhesive layer is more than 1/4 of the thickness of the embedding photocatalyst layer, and the bonding strength with the base material is satisfactory. Here, the thickness of the photocatalyst layer is determined from the analysis of the component elements constituting the photocatalyst particles in the cross-sectional direction measured by EPMA or the like. It is composed of an upper layer portion and an embedded portion with a substantially constant amount of component elements constituting the photocatalyst particles. The entrance portion is located between the depth at which the amount of the component elements constituting the photocatalyst particles starts to decrease to the depth at which the amount of the component elements constituting the binder starts to become a certain depth.

The surface treatment agent attached to the photocatalyst is mainly composed of components added to disperse the starting material sol of the photocatalyst particles. Specific examples include pentaerythritol, trimethylolpropane, triethanolamine, trimethylolamine, silicone resins, and alkylchlorosilanes.

Examples of the light source containing light with a wavelength of 1.7 mW/cm2 or more and 390 nm or less include BLB fluorescent lamps, ultraviolet lamps, germicidal lamps, xenon lamps, mercury lamps, and the like.

The reason why it must contain light with a wavelength of 1.7 mW/cm2 or more and 390 nm or less is that the dispersant components such as silicone resin have a certain degree of photocorrosion resistance, and if there is no ultraviolet intensity of this degree, it will not decompose. At this time, the shorter the ultraviolet wavelength, the faster the decomposition of the dispersant, but due to the different types of binders, the binder may decompose, and it is also harmful to the human body. Therefore, it may be 250 nm or more. In addition, when the illuminance reaches about 3mW/cm2, the decomposition speed increases as the illuminance increases, but even if the illuminance increases to 3mW/cm2 or more, it does not contribute much to the increase in the decomposition speed, so 3mW/cm2 or less is sufficient.

The above process is schematically shown in FIG. 47. On the substrate 1, a part of the lower layer of the photocatalyst layer 2 is buried in the adhesive layer 6 through the adhesive layer 6. 6a is a layer composed of a surface treatment agent or the like that suppresses photocatalytic activity. UV means light containing wavelengths of 1.7 mW/cm2 or more and 390 nm or less.

Hereinafter, a description will be given of forming a layer mainly composed of the photocatalyst particles 3 and the thermosetting resin 6 on the surface of the substrate, and irradiating ultraviolet rays similarly to expose the photocatalyst layer. (Refer to Figure 48) In this method, thermosetting resin is also used to firmly fix the photocatalyst particles 3 on the substrate, and light with a wavelength of 1.7 mW/cm2 or more and 390 nm or less is irradiated to light on the surface of the photocatalyst particles. The irradiated part produces a photocatalytic reaction, which preferentially decomposes and vaporizes the thermosetting resin in the direction of the surface treatment agent and the light source, and exposes the photocatalyst particles to the air, so that sufficient photocatalytic activity can be obtained.

In addition, with regard to the method of forming a layer mainly composed of photocatalyst particles and thermosetting resin, for example, a thermosetting resin, diluent, and curing agent are sequentially added to a fully dispersed photocatalyst sol suspension to obtain a mixed liquid, and the mixed liquid is coated The cloth is formed on the surface of the substrate and heat-treated.

Here, the crystal particle diameter of the sol in the photocatalyst sol suspension may be 0.05 μm or less, more preferably 0.01 μm or less. This is because the smaller the crystal grain size, the higher the photocatalytic activity. It is also desirable that the sol in the photocatalyst sol suspension be as monodisperse as possible. The better the dispersion, the more uniform coating film can be formed.

The thermosetting resin used here preferably has photo-corrosion resistance to white light and light of normal fluorescent lamp intensity. This is because it has excellent durability during use. In this sense, silicone resins and fluorine are particularly ideal for grease.

The diluent is used to reduce the viscosity of the mixed liquid composed of the photocatalyst sol and the thermosetting resin, so that the mixed liquid can be easily coated and added on the surface of the substrate. However, the diluent used here can basically be used as long as it is a solvent that can achieve this purpose. For example, water, ethanol, propanol, etc. can be used.

Although there are spray coating methods, roll coating methods, dip coating methods, spin coating methods, etc., for applying the mixed solution to the substrate, any of these methods may be used, or other methods may be used.

Heat treatment furnaces generally use electric furnaces, gas furnaces, vacuum furnaces, pressurized furnaces, etc., but are not limited to this.

It is also possible to form a layer mainly composed of photocatalyst particles and thermosetting resin on the surface of the substrate by a thermosetting resin layer or a photocurable resin layer (intermediate layer: C) (see FIG. 49).

According to this method, even if there are irregularities on the substrate, the thermosetting resin layer or the photocurable resin layer arranged between the substrate and the photocatalyst layer can form an extremely smooth surface before coating the photocatalyst layer. It is easy to form a uniform photocatalyst layer. In addition, the thermosetting resin layer or photocurable resin layer disposed between the substrate and the photocatalyst layer sufficiently forms the bond with the substrate. Therefore, even if there are irregularities on the surface of the substrate, the photocatalyst particles can be formed thinly. Together with the layer composed of thermosetting resin, the photocatalyst particles can also be concentrated near the surface of the substrate, so that the subsequent process of irradiating light containing light with wavelengths of 1.7 mW/cm2 or more and 390 nm or less can be completed in a shorter time. In addition, because there is a layer composed of the above photocatalyst particles and thermosetting resin, even if it is decomposed and vaporized during the subsequent process and use, ultraviolet rays with sufficient intensity cannot reach the thermosetting resin layer or photocurable resin layer arranged in the middle. Therefore, the thermosetting resin for this part can be arbitrarily selected. For example, an inexpensive epoxy resin can be selected in order to reduce costs, and a colored resin can also be used in order to maintain pattern properties.

Here, the method for forming the thermosetting resin layer disposed between the substrate and the photocatalyst layer includes, for example, coating the surface of the substrate with a mixture obtained by adding a diluent to the thermosetting grease and then adding a curing agent, and using heat treatment Or placed and cured to form. In addition, when the layer disposed in the middle of the photocatalyst is a photocurable resin layer, the heat treatment is replaced by irradiation with light containing ultraviolet rays. Here, in order to reduce the viscosity of the mixed liquid, it is easy to coat the mixed liquid on the surface of the substrate and add a diluent. Therefore, the diluent used here can basically be any solvent that can achieve this purpose. For example, water, ethanol, propanol, etc. can be used.

Furthermore, as shown in Figure 50 (a) and (b), according to the above method, the gap formed on the photocatalyst layer exposed on the surface of the substrate is preferably filled with particles smaller than the gap (interstitial particles: 4), In order to further improve the wear resistance.

The size of particles smaller than the gap may basically be smaller than the average value of the generated pore diameter or unevenness. The amount of particles smaller than the gap is desirably such that the open porosity added to the surface becomes 20% or less. Because this kind of pollution is difficult to adhere.

Specific examples are listed below.

Example 38: On the surface of a 10cm square alumina substrate, it was coated on a titania sol with an average particle size of 0.01μm (obtained by dispersing treatment with an amine-based dispersant) and added 10% by weight in sequence The mixture of silicone resin, diluent, and curing agent was calcined at 150°C to obtain a comparative sample. The sample was irradiated with various light sources for a predetermined time to obtain a sample. The deodorant R30 (L) at the time of light irradiation was evaluated with respect to the obtained sample.

Here, the deodorant R30 (L) during light irradiation means that the sample surface is placed at a distance of 8 cm from the light source (BLB fluorescent lamp, 4W) in an 11-liter glass container, and methyl mercaptan is injected with an initial concentration of 3 ppm The concentration change rate in the container after 30 minutes of light irradiation.

The results are shown in Table 22. (Table 22)<

> Results The UV intensity is 1.69mW/cm2 or more and the deodorization is more than 50%. When the UV intensity is 2mW/cm2 or more, the deodorization R30(L) is a good result of more than 70%. Here, the reason why the ultraviolet intensity is 1.69mW/cm2 or higher shows good results, which can be explained as the photocatalytic reaction occurs in the light irradiation part of the photocatalyst particle surface, and the thermosetting resin in the direction of the surface treatment agent and the light source is preferentially decomposed and vaporized. This is because the photocatalyst particles are exposed to the air.

Example 39: On the surface of a 10cm square alumina substrate, a solution formed by adding a diluent and a curing agent to a silicone resin was coated, and after drying at room temperature for about 6 hours, the coating was applied to an average particle size of 0.01μm. A mixture of 10% by weight of siloxane resin, diluent and curing agent was added to the titanium oxide sol (obtained by dispersion treatment with an amine-based dispersant) and calcined at 150°C to obtain a comparative sample. The sample is irradiated with various light sources for a predetermined time to obtain a sample. The deodorant R30 (L) at the time of light irradiation was evaluated with respect to the obtained sample.

The results are shown in Table 23. (Table 23

As a result, the ultraviolet intensity was 1.69 mW/cm2 or more, and the deodorization performance was more than 60%. When it was 2 mW/cm2 or more, the deodorization R30 (L) was a good result of more than 80%. Here, the reason why the ultraviolet intensity is above 1.69mW/cm2 shows good results can be explained as the photocatalytic reaction occurs in the light-irradiated part of the photocatalyst particle surface, which can make it adhere to the photocatalyst that cannot be vaporized or decomposed by heat treatment. The surface treatment agent on the light-irradiated surface of the particle surface is preferentially decomposed and vaporized, and as a result, the photocatalyst particle is exposed to the air.

Example 40 On the surface of a 10cm square alumina substrate, a solution prepared by adding a diluent and a curing agent to a silicone resin was coated, and after drying at room temperature for about 6 hours, the coating was applied to an average particle size of 0.01μm. A mixture of 10% by weight of siloxane resin, diluent, and curing agent was added to the titanium oxide sol (obtained by dispersion treatment with an amine-based dispersant), and calcined at 150°C. The particle gap on the surface of the component at this stage is about 0.1-0.2 μm on average. Then, after irradiating light (ultraviolet lamp) with an ultraviolet intensity of 2mW/cm2 for 3 days, it is confirmed that R30(L) exceeds 80%, and then the surface is coated with 70% by weight of titanium oxide with an average particle diameter of 0.0035μm. The titanium sol was dried at 110°C to obtain a sample. This sample also showed good results with an R30 (L) of 81%. In addition, the sliding test was performed with a plastic rubber. The sample without tin oxide had scratches after 5 times of sliding or less, and the titanium oxide had peeled off, but the sample with tin oxide added did not change even after sliding for more than 10 times. It has been confirmed from the above that by filling the gap formed on the surface of the member with tin oxide particles smaller than the gap, the wear resistance can be improved.

As can be seen from the above description, even in the case of forming a layer with photocatalytic action at 300°C or lower, a member with good photocatalytic activity can be provided.

Secondly, although the purpose of exposure is the same as that caused by ultraviolet irradiation, a different method is used to describe a method that can provide a multifunctional material with sufficient photocatalysis even when firing at 300°C or less.

In this method, metal particles are fixed on the surface of the titanium oxide sol before adding surface treatment agents such as dispersants and surfactants to the titanium oxide sol prepared by the hydrothermal method or the sulfuric acid method.

The so-called metal particles here refer to metal particles that can capture electrons when they are supported on titanium oxide by irradiating light on titanium oxide to generate electrons and holes, specifically Ag, Cu, Pt, Pd, Ni, Fe, Co Wait.

Among the methods of fixing metal particles on the surface of the titanium oxide sol, the photoreduction method is simple. The titanium oxide sol used here is desirably prepared by a hydrothermal method or a sulfuric acid method, but it is not limited thereto. The sulfuric acid method referred to here is a method for synthesizing titanium oxide by the procedure shown below.

First, anatase is reacted with sulfuric acid to make Ti, Fe, etc., become water-soluble sulfates, and then extracted with water to prepare a sulfate solution whose main components are Ti and Fe. Next, insoluble suspended matter such as SiO2 is removed. Then it is cooled to 10-15°C, and iron sulfate is precipitated and separated and removed. Next, the sulfuric acid titanium oxide in the solution is hydrolyzed to produce titanium hydroxide containing titanium. The obtained titanium hydroxide containing titanium is subjected to hydrothermal treatment in high-temperature and high-pressure water (generally at a saturated vapor pressure of 110°C or more and 200 or less) using a pressure device such as an autoclave to crystallize to obtain a titanium oxide sol.

In addition, the so-called hydrothermal method uses a pressure device such as an autoclave to hydrothermally treat titanium sources such as titanium tetrachloride and titanium sulfate in high-temperature and high-pressure water (generally at a saturated vapor pressure of 110°C or more and 200°C or less) to cause hydrolysis. And the method of obtaining titanium oxide sol.

The method shown below specifically explains the method of fixing metal fine particles to the surface of the titanium oxide sol by the photoreduction method.

First, the titanium oxide suspension prepared by the hydrothermal method or the sulfuric acid method is made acidic or alkaline. The isoelectric point of titanium oxide is pH 6.5, and because it is neutral, it is easy to aggregate. In addition, it is better to use ammonia in order to adjust to alkalinity. Alkali metals such as Na and K are easy to adhere firmly to titanium oxide. If these metals occupy the active sites of titanium oxide first, the photocatalytic activity will be reduced, and at the same time, the adhesion of Ag, Cu, Pt, Pd, Ni, Fe, Co, etc. will be prevented. On the active point of titanium oxide.

Next, the titanium oxide sol suspension and the metal salt solution with approximately the same pH are mixed to form the titanium oxide sol suspension, and the metal is fixed by irradiating with ultraviolet light. If necessary, precipitate the excess metal and remove it from the solution. The metal salt solution here refers to a solution consisting of a metal salt capable of capturing electrons and a solvent when light is irradiated on the titanium oxide to generate electrons and holes when it is supported on titanium oxide. More specifically, it refers to a solution consisting of a metal salt capable of capturing electrons and a solvent. A solution consisting of salts and solvents containing Ag, Cu, Pt, Pd, Ni, Fe, Co, etc. Examples of salts containing Ag, Cu, Pt, Pd, Ni, Fe, Co, etc. include silver nitrate, copper acetate, copper carbonate, copper sulfate, cuprous chloride, copper chloride, chloroplatinate, chlorinated Palladium, nickel chloride, cobalt chloride, ferrous chloride, ferric chloride, etc. In addition, as the solvent, water, ethanol, propanol, etc. can be used, but the same kind of solvent as the titanium oxide sol suspension to be formed can also be used. Add a pH adjuster to the solvent as needed. As the pH adjuster on the acid side, nitric acid, sulfuric acid, hydrochloric acid, etc. can be used. In addition, ammonia is used as a pH adjuster on the alkali side.

When irradiating light containing ultraviolet rays, pay attention to the points shown below. First of all, as long as the light source irradiates light containing ultraviolet light. Specific examples include ultraviolet lamps, BLB lamps, xenon lamps, mercury lamps, fluorescent lamps, and the like. There is basically no problem with the method of irradiating light containing ultraviolet rays, but first, it can be irradiated from above the container. Because there is no container to absorb ultraviolet light. Secondly, the distance between the light source and the container can be several cm to several 10 cm. If it is too close, the heat from the light source may dry out the top of the solution. If it is too far, the illuminance will decrease. The irradiation time varies depending on the illuminance of the light source, and when irradiated for a few seconds to several tens of seconds, the metal is firmly attached to the photocatalyst particles.

Next, a thin film formed by coating the above-mentioned metal-supported titanium oxide sol and heat-treating is formed on the surface of the substrate, thereby forming a multifunctional material with photocatalytic effect.

The heat treatment is usually a hydrothermal treatment using roasting in the atmosphere using an electric furnace, a gas furnace, or the like, an autoclave, or the like, but it is not limited to this.

The average particle diameter of the titanium oxide particles in the titanium oxide film obtained by such a method is preferably 1 μm or less. When the particle size is larger than this, since the specific surface area is reduced, the photocatalytic activity is reduced.

In addition, a thin film formed by coating the sol of claim 1 on the surface of the base material and heat-treating it is formed by an adhesive, thereby forming a member having a photocatalytic effect. Due to the use of an adhesive, the adhesion to the substrate can be improved.

The specific method differs depending on whether the adhesive is a thermoplastic adhesive or a thermosetting adhesive. If each embodiment shown below satisfies the above configuration, it goes without saying that other methods can be used. Specific examples of the thermoplastic binder include thermoplastic binders such as acrylic resins, inorganic vitreous materials such as glazes, and solders. Moreover, as a thermosetting adhesive, a fluororesin, an epoxy resin, a silicone resin, etc. are mentioned.

When a thermoplastic adhesive is used, a member having a photocatalytic effect is produced in the procedure shown below. First, a thermoplastic adhesive is coated on the surface of the substrate. Next, a titanium oxide sol supporting metal particles is coated thereon, and heat treatment is performed. The heat treatment is performed at a temperature lower than the heat-resistant temperature of the base material and higher than the softening point of the thermoplastic adhesive. By performing the heat treatment at such a temperature, a part of the lower layer of the titanium oxide layer supporting the metal particles is buried in the adhesive layer, thereby enabling the base material and the metal particle-supporting titanium oxide thin film to be firmly bonded.

In addition, when a thermosetting adhesive is used, a member having a photocatalytic effect is manufactured in the procedure shown below. First, a diluent and a curing agent are sequentially added to the thermosetting adhesive to make a mixed solution, which is coated on the substrate and cured by heat treatment and other methods. Then, a mixed solution prepared by sequentially adding a thermosetting agent resin, a diluent, and a curing agent to the titanium oxide sol supporting the metal particles is coated thereon, and cured by a method such as heat treatment.

In addition, as a substitute for the thermosetting adhesive, a photocurable adhesive can also be used in the same way.

In this way, in the titanium oxide sol prepared by the hydrothermal method or the sulfuric acid method, the metal particles such as Ag, Cu, Pt, Pd, Ni, Fe, and Co are added before the surface treatment agent such as dispersant and surfactant is added. Fixed on the surface of the TiO2 sol, so as to pre-cover the active part of the titanium oxide sol with metal particles such as Ag, Cu, Pt, Pd, Ni, Fe, Co, and even add a dispersant, a surfactant, etc. to the surface in the subsequent process Treatment agent, these substances are adsorbed on the active part of the titanium oxide sol without losing activity. Therefore, the photocatalyst sol can be stably dispersed by the action of surface treatment agents such as dispersants and surfactants, and a homogeneous film can be formed on the surface of the substrate. At the same time, it can be prevented even if calcination is performed at a low temperature below 300°C. Surface active agents such as dispersants and surfactants are adsorbed on the active part of the photocatalyst particle layer formed on the surface of the substrate, and the photocatalytic effect is reduced. At the same time, Ag, Cu, Pt, and Pt, which occupy the active part of the titanium oxide sol, are used. Pd, Ni, Fe, Co and other metal particles have the effect of capturing electrons and improve photocatalytic activity.

Specific examples are listed below.

In Example 41, water was added to titanium tetrachloride in a cold water bath to obtain a liquid substance, and the obtained liquid substance was subjected to a hydrothermal treatment at 140° C. in an autoclave to obtain an anatase-type titanium oxide sol. The obtained anatase-type titanium oxide sol is dispersed in nitric acid. The pH of the dispersion was 0.8. A 3-5% (by weight) copper sulfate aqueous solution whose pH was adjusted to approximately 0.8 with nitric acid was added to the dispersion, and light containing ultraviolet rays was irradiated from above the container. At this time, a 4W 8LB lamp was used as the light source, and the solution was irradiated for 15 minutes from a distance of about 10 cm. A dispersant composed of organic acetate is added to the solution to stabilize the sol. The sol was coated on a 15 cm square ceramic tile substrate and heat-treated at 150° C. to obtain a sample. The deodorant property R30 (L) and antibacterial property at the time of light irradiation were measured for the obtained sample.

The deodorant R30 (L) during light irradiation means that the sample is placed in an 11-liter glass container at a distance of 8 cm from the light source (BLB fluorescent lamp, 4W), and methyl mercaptan gas is injected into the container. The initial concentration is 3ppm, the concentration change rate after 30 minutes of light irradiation.

In addition, for the antibacterial properties, the test was performed with Escherichia coli (Escherichia coli W3110 strain). Drop 0.15ml (10000-50000CFU) of bacterial liquid on the uppermost surface of the above sample previously sterilized with 70% ethanol, place it on a glass plate (100×100), and make it close to the outermost surface of the substrate, as the sample . After irradiating with a white light (3500 Lux) for 30 minutes, the bacterial solution of the irradiated sample was wiped with sterile gauze and recovered in 10 ml of physiological saline, and the survival rate of the bacteria was determined as an evaluation index. The evaluation criteria +++, ++, +, and-are the same as above.

As a result, R30(L) showed a good result of 85%, and the antibacterial property showed a good result of +++.

In Comparative Example 42, water was added to titanium tetrachloride to obtain a liquid in a cold water bath, and the obtained liquid was subjected to a hydrothermal treatment at 140°C in an autoclave to obtain anatase-type titanium oxide sol. The obtained anatase-type titanium oxide sol is dispersed in nitric acid. The pH of the dispersion was 0.8. A dispersant composed of organic acetate was added to the solution to stabilize the sol. The sol was coated on a 15cm square tile substrate and heat-treated at 150°C to obtain a sample. The deodorant R30 (L) and antibacterial properties during light irradiation were measured.

As a result, R30 (L) was 5%, and the antibacterial property was -, both of which were insufficient.

In Example 43, water was added to titanium tetrachloride in a cold water bath to obtain a liquid substance, and the obtained liquid substance was subjected to a hydrothermal treatment at 140° C. in an autoclave, thereby obtaining anatase-type titanium oxide sol. The obtained anatase-type titanium oxide sol is dispersed in nitric acid. The pH of the dispersion was 0.8. A 3-5% (by weight) copper sulfate aqueous solution whose pH was adjusted to approximately 0.8 with nitric acid was added to the solution, and light containing ultraviolet rays was irradiated from above the container. At this time, a 4W BLB lamp was used as the light source, and light was irradiated for 15 minutes from a distance of about 10 cm from the solution. A dispersant composed of organic acetate is added to the solution to stabilize the sol. Next, apply a mixture of diluent propanol and curing agent to the silicone resin on the surface of a 10 cm square alumina substrate, and apply the mixture prepared by the above method to the member after drying at 100°C. A mixture of 20% (weight, relative to the amount of titanium oxide) of siloxane resin, propanol, and curing agent was sequentially added to the sol, and the mixture was calcined at 150°C to obtain a sample. The deodorant R30 (L) evaluation at the time of light irradiation was measured for the obtained sample.

As a result, R30 (L) showed a good result of 80%.

In Comparative Example 44, water was added to titanium tetrachloride to obtain a liquid in a cold water bath, and the obtained liquid was subjected to a hydrothermal treatment at 140° C. in an autoclave to obtain anatase-type titanium oxide sol. The obtained anatase-type titanium oxide sol is dispersed in nitric acid. The pH of the dispersion was 0.8. Add a dispersant composed of organic acetic acid to the solution to stabilize the sol, and then coat the surface of a 10cm square alumina substrate with a silicone resin, which is made by adding diluent propanol and curing agent in sequence. The mixed solution is applied to the sol prepared by the above method on the member dried at 100°C by adding 20% (by weight, relative to the amount of titanium oxide) of siloxane resin, propanol, and curing agent in sequence. , Calcined at 150°C to obtain a sample, and the deodorant R30 (L) during light irradiation was measured on the obtained sample. As a result, R30 (L) was 22%, which was insufficient.

As can be seen from the above description, in the titanium oxide sol prepared by the hydrothermal method or sulfuric acid method, before adding surface treatment agents such as dispersants and surfactants, Ag, Cu, Pt, Pd, Ni, Metal particles such as Fe and Co are fixed on the surface of the titanium oxide sol, and even if it is fired at a low temperature below 300°C, it can provide a member with sufficient photocatalysis on a heat-labile substrate, such as a plastic material.

The above embodiments mainly describe anatase-type TiO2, and the following description relates to rutile-type TiO2.

Fig. 51 is a block diagram showing the manufacturing process of a multifunctional material using rutile TiO2. The present invention first forms a rutile TiO2 film on the surface of a substrate such as a ceramic tile. As a method for forming a rutile TiO2 thin film, TiO2 sol, titanium alkoxide, Ti sulfate, Ti chloride solution, etc. are used as raw materials, coated on a substrate, and then subjected to heat treatment.

When using TiO2 sol, because the TiO2 isoelectric point is 6.5, which is approximately neutral, it is easy to uniformly coat the substrate with an acid or alkali-dispersed aqueous solution. When the substrate at this time is a metal, an alkali dispersion is preferable from the viewpoint of corrosion resistance. Examples of the acid include sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, and organic acids. In the case of alkalis, ammonia, alkali metal-containing hydroxides, etc. can be cited. From the viewpoint that metal contaminants are not generated after heat treatment, ammonia is particularly preferable. In addition, organic acids and phosphoric acid-based dispersants, surface treatment agents, and surfactants may be added to these dispersion liquids. In addition, if the particle size is small, initial sintering occurs at a lower temperature, and a photocatalyst film with excellent peel strength can be obtained at a low temperature. Therefore, the average particle size of the TiO2 sol may be 0.05 μm or less, preferably 0.01 μm or less.

As a method of coating on the substrate, compared with spraying, dipping, roll coating, spin coating, CVD, electron beam evaporation, sputtering, etc. of the above-mentioned raw materials, it is desirable that no special equipment is required and a stable coating film can be formed.

The heat treatment can use air roasting using an electric furnace and a gas furnace, or hydrothermal treatment using an autoclave.

On the other hand, a solution (a metal ion-containing aqueous solution) of at least one of Cu, Ag, Fe, Co, Pt, Ni, Pd, and Cu2O is prepared in advance, and the solution is coated on the rutile TiO2 film. Here, when the metal salt aqueous solution is applied, the metal salt aqueous solution does not need to be transferred to the back surface of the substrate. As the solution in the metal salt solution, water, ethanol, etc. can be used. In the case of using water, it is also effective to add alcohol, unsaturated hydrocarbon, etc. as a protective oxidizing agent. Furthermore, using ethanol as a solution is not harmful compared to other solvents such as ether, acetone, methanol, for example, in terms of not causing rust on metal substrates and fast drying speed, which is desirable. .

Next, in order to improve the efficiency of supporting the above-mentioned metal salt aqueous solution, it is dried at room temperature to 110°C, and the metal salt is irradiated with light of 390 nm or less to reduce metal ions, and the metal is precipitated and fixed on the rutile TiO2 thin film. Here, as the lamp used for irradiation, an ultraviolet lamp, a BLB lamp (near ultraviolet) lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, etc. can be used. In the irradiation at this time, in order to increase the irradiation rate, the light may be irradiated vertically on the irradiation surface.

The following is a specific example. Example 45 was sprayed on a 10 cm square alumina substrate, coated with an ammonia dispersion of TiO2 sol with an average particle size of 0.01 μm, and fired at 900°C to form a rutile TiO2 film. Then, the rutile TiO2 thin film was coated with a copper acetate aqueous solution by spraying, and then photoreduction was performed (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, and the irradiation time was 10 seconds) to obtain a sample. The photoactivity A (L) was evaluated for the obtained sample.

The optical activity A(L) represents the absolute value of the slope when the reaction curve when the gas concentration is on the Y axis and the reaction time is on the X axis is approximated to a straight line. That is, if the concentration at time t is Xt, then Xt=X0·10-A(L)t(1). Therefore, the light containing ultraviolet rays passes through the photocatalyst film to be irradiated, and by observing the elapsed time t Decrease the concentration of the decomposition gas, and find a certain type of decomposition gas. In this experiment, methyl mercaptan, which is a malodorous component in the decomposition gas, was used. The initial concentration of methyl mercaptan was adjusted to 2 ppm, and the sample was set in a cylindrical container with a diameter of 26 cm × a height of 21 cm, and a 4W BL8 fluorescent lamp was used. At a distance of 8 cm from the sample, the decomposition gas was obtained by observing the time change of the concentration of methyl sulfuric acid when the light was irradiated.

The results obtained are shown in Figure 52 and Figure 53. Fig. 52 and Fig. 53 are graphs showing the relationship between the Cu concentration in the solution and the photoactivity A(L). Fig. 52 shows the case where the atomized copper acetate aqueous solution is dried and then photoreduced, and Fig. 53 shows the case where the atomized copper acetate aqueous solution is dried and then photoreduced. It is the case where the copper acetate aqueous solution in a dry state is subjected to photoreduction.

In the case of photoreduction with the atomized copper acetate aqueous solution in a dry state as shown in Fig. 53, even if the Cu concentration in the solution increases from 0.001% by weight to 0.1% by weight, A(L) is 3× 10-5 degree, no change, reaching saturation.

On the contrary, in the case of photoreduction after drying the atomized copper acetate aqueous solution in FIG. 52, at 0.001% by weight, it is about 2×10-5, which is about the same as the case without drying. However, if it is increased to 0.1% by weight, it is observed that it reaches about 1×10-2, and A(L) increases drastically.

Example 46 was carried out in the same manner as Example 45. The rutile TiO2 film was formed on floor tiles and wall tiles, and Cu (copper acetate aqueous solution coated and dried) was fixed on the rutile TiO2 film by photoreduction Next, the detection results of the relationship between the concentration of the metal component in the solution and the malodor removal rate R30 are shown in Figs. 54 and 55.

It can be seen from these figures that the photoreduction treatment after drying can remove malodorous components if the concentration of the metal components in the solution is large to a certain extent, even if the substrate is ceramic tiles.

In Example 47, a 15 cm square ceramic tile substrate was sprayed to coat an ammonia dispersion of TiO2 sol with an average particle size of 0.01 μm, and fired at different temperatures to form a rutile TiO2 film. Then, the rutile TiO2 film was coated with a copper acetate aqueous solution by spraying, and then photoreduction was performed (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, and the irradiation time was 10 seconds) to obtain a sample. The deodorant R30 was evaluated for the obtained sample.

The results obtained are shown in Figure 56. The R30 value at 900°C (open porosity 10%) is better than that of the rutile-only sample that does not support metal. In addition, if the temperature was increased to 1000°C (open porosity 30%), the R30 value of the sample not supporting the metal was significantly reduced, and some reduction was observed even for the sample to which Cu was added. Therefore, there are two reasons for the decrease in deodorization properties at 1000°C compared to 900°C. One is that the area of the rutile TiO2 film of the photocatalyst that can contact the decomposition gas decreases with the decrease in the open porosity. It is considered to be the main cause of the decrease in the deodorization performance of the metal sample not supported. Another reason is that as the open porosity decreases, the area where the metal particles can be deposited by the photoreduction method also decreases. Because the mean free path in electronic movement becomes larger.

In addition, FIG. 57 shows the relationship between the concentration of Ag and Cu in the solution and the color difference during film coating. It can be seen from this figure that Cu is smaller in chromatic aberration and brightness change than Ag, and the coloring is not conspicuous. In addition, the difference in coloring is Cu, and ESCA (electron beam spectroscopy for chemical analysis) etc. have been used to detect the 0-valent and mono-valent substances of Cu, so it can be considered that this is not easy to develop. The impact of valence components.

In Example 48, a 15 cm square ceramic tile substrate was sprayed to coat an ammonia dispersion of TiO2 sol with an average particle size of 0.01 μm, and fired at different temperatures to form a rutile TiO2 film. Next, an aqueous solution of silver nitrate was coated on the rutile TiO2 film by spraying, and then photoreduction was performed (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, and the irradiation time was 10 seconds) to obtain a sample. The evaluation results of the porosity, deodorization and abrasion resistance of the rutile TiO2 thin film in the obtained samples are shown in FIG. 58.

When the porosity is 10% or more, good deodorization is shown, and when the porosity is less than 40%, the abrasion resistance can be 0 or more.

Regarding the abrasion resistance, sliding friction using a plastic rubber was performed to compare appearance changes and evaluate. The evaluation index is expressed as follows.

: No change relative to 40 times of repetition : Scratch in 10 or more 40 times or less slidings, peeling of titanium oxide film : Scratch in sliding of 5 to 10 times or less, titanium oxide film peeling ×: In 5 There were scratches on sliding less than the second time, and the titanium oxide film peeled off.

Example 49: On a 10cm square alumina substrate with a glaze layer formed in advance, a spraying method was used to coat an ammonia dispersion of TiO2 sol with an average particle size of 0.01μm, and fired at 850°C above 1000°C to form a rutile TiO2 film . Next, an aqueous silver nitrate solution was spray-coated on the rutile TiO2 film, and then photoreduced (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, and the irradiation time was 10 seconds) to obtain a sample.

The antibacterial properties, abrasion resistance, peeling resistance, stain resistance, acid resistance, alkali resistance, and silver coloring properties of the obtained samples were evaluated.

Regarding antibacterial properties, the test was conducted with Escherichia coli (Escherichi a coli W3110 strain). Drop 0.15 ml of bacterial liquid on the outermost surface of the multifunctional material pre-sterilized with 70% ethanol, place it on a glass plate (100×100), and adhere to the outermost surface of the substrate as a sample. After irradiating with a white lamp (3500 Lux) for 30 minutes, wipe the irradiated sample with sterile gauze and the bacterial solution that keeps the sample under the shielded condition, and recover it in 10ml of physiological saline to obtain the survival rate of the bacteria as Evaluation index. The evaluation indicators +++, ++, +, and-are the same as above.

The peel resistance test is a test that is more severe than the abrasion test. The sanding rubber (LION TYPEWRITER ERASER 502) with greater shear strength is used instead of the plastic rubber. The specific evaluation method is to rub the surface of the sample 20 times with a sand rubber with equal force, and visually observe the scratch state compared with the standard sample. The evaluation criteria are as follows.

: No change at all : Slight change is confirmed by light addition and subtraction method : Slight change is confirmed ×: Change is confirmed at a glance The so-called stain resistance test is a test about the difficulty of adhesion of dirt. The specific evaluation method is to use 0.5% methylene blue aqueous solution to create dirt on the surface of the sample, dry and wash with water, and visually observe whether there is dirt. The evaluation criteria are expressed as follows.

: Completely eliminate dirt : Although the color of the dirt is not clear, there is a small amount of residue : A light dirt color remains ×: A significant remaining dirt color Regarding acid resistance, after immersing in a 10% HCl aqueous solution for 120 hours, visually The evaluation was made by observing the abnormal changes of the Ag-supported rutile TiO2 thin film layer on the surface of the substrate. The evaluation criteria are expressed as follows.

: No change : Very slight discoloration : Slight discoloration ×: Obvious discoloration Regarding alkali resistance, immerse in a 5% NaOH aqueous solution for 120 hours, and visually observe the Ag-supported rutile TiO2 film on the surface of the substrate The abnormal change of the layer is evaluated based on this, and the evaluation criteria are as follows.

: No change : Very slight discoloration : Slight discoloration ×: Obvious and discoloration Regarding the silver colorability, it was evaluated by visual comparison with a sample to which Ag was not added. The evaluation criteria are expressed as follows.

: No coloring : Very slightly colored : Slightly colored ×: Brown colored part The above seven evaluation results are summarized in Table 24. In addition, the influence of the film thickness and the firing temperature on the antibacterial properties is shown in Table 25. (Table 24) The relationship between the thickness of the photocatalyst film and various characteristics

(Table 25) The influence of film thickness and calcination temperature on the antibacterial properties of the photocatalyst film

Regarding antibacterial properties, the photocatalyst film produced in this example had a film thickness of 0.1 μm or more and 1 μm or less, and if the firing temperature was set to be appropriate, it showed a good result of +++. However, as shown in Table 24, if the film thickness is 0.2 μm or less, the antibacterial property of the sample calcined at a high temperature of 980°C is ++. A tendency to decrease in antibacterial properties is seen. It is considered that this is because the photocatalyst film is partially buried in the scratch layer due to the softening of the glaze layer. In addition, although Ag itself has antibacterial activity, the antibacterial property depends on the firing temperature. The antibacterial activity of the composite member made according to the method of the present application also shows that it is related to the characteristics of the rutile TiO2 film other than the antibacterial effect of Ag (because Ag It is supported after firing as described above).

In addition, it can be considered that in all samples, a certain degree of sinking of the photocatalyst film into the glaze layer occurred with the softening of the glaze layer. However, this example has confirmed that if the firing temperature is appropriate, the photocatalyst can be made at least 0.1μm or more. The film remains on the outermost layer of the glaze layer.

Regarding the abrasion resistance, the photocatalyst thin film produced in this example showed a good result of in the range of 0.1 μm or more and 1 μm or less in film thickness. This result is different from the sample made by the same manufacturing method without glazing in the middle for comparison, and it shows a very good result. It is believed that this is because the glaze is intervened in the middle, and part of the lower layer of the photocatalyst film is buried in the glaze layer due to the softening of the glaze during firing.

On the contrary, for the peel resistance test, when the thickness of the photocatalyst film is increased, the value is when the thickness is 0.1 μm or more and 0.4 μm or less, the value is when the thickness is 0.4 μm or more and 0.9 μm or less, and the value is × when the thickness of the photocatalyst film increases. Poor tendency. It is considered that this is because the ratio of the buried thickness to the film thickness in the glaze layer increases, making it difficult to peel off. In addition, those who are not abnormal in the abrasion resistance test are poor in the peel resistance test, which is caused by the difference in the magnitude of the shearing force.

Regarding contamination resistance, when the thickness of the photocatalyst film is 0.1μm or more and 0.4μm or less, it is , when it is 0.4μm or more and 0.9μm or less, it is , and when it is 1μm, it is ×. The tendency to get worse.

Regarding the acid resistance, the photocatalyst thin film produced in this example showed good results within the range of 0.1 μm or more and 1 μm or less. However, when it is 0.4 μm or more and 1 μm or less, it is , and when it is 0.1 μm or more and 0.4 μm or less, it is , and those with a thin film thickness show satisfactory values.

Regarding alkali resistance, the photocatalyst thin film produced in this example showed good results in a range of 0.1 μm or more and 1 μm or less in thickness. However, when it is 0.4 μm or more and 1 μm or less, it is , and when it is 0.1 μm or more and 0.4 μm or less, it is , and those with a thin film thickness show satisfactory values. Regarding the Ag colorability, when the thickness of the photocatalyst film is 0.1μm or more and 0.4μm or less, it is , when it is 0.4μm or more and 0.9μm or less, it is , and when it is 1μm, it is ×. The tendency to get worse. This tendency is consistent with stain resistance.

It can be seen from the above seven tests that the thickness of the photocatalyst film is 0.1 μm or more and 0.9 μm or less, preferably 0.1 μm or more and 0.4 μm or less. In addition, it can be seen that the photocatalyst film is fixed on the substrate through the glaze layer to improve the wear resistance.

In addition, the characteristics of the design are also changed by the film thickness. That is, at 0.2 μm or more and 0.4 μm or less, the interference of visible light and the photocatalyst film is used to produce an iridescent stripe pattern, giving a special impression in appearance. On the contrary, at 0.2 μm or less and 0.4 μm or more and 0.9 μm or less, the above-mentioned iridescent stripe pattern does not occur. The color of the base material or the color or pattern composed of glaze or the appearance related to the combination can be used as it is.

In Example 50, an ammonia dispersion of TiO2 sol with an average particle size of 0.01 μm was sprayed on a 15 cm square ceramic tile substrate, and fired at 900° C. to form a rutile TiO2 film with a thickness of 0.8 μm. Next, on the surface of the tile, the coating amount of the copper acetate aqueous solution (solution concentration 0.2% by weight, 0.5% by weight, 1% by weight) was changed, and the copper acetate aqueous solution was coated by spraying method, and then polished. Reduction (the light source is a 20W BLB lamp, the distance from the light source to the sample is 10 cm, and the irradiation time is 10 seconds) to obtain a sample. The antibacterial properties of the obtained samples were evaluated. The residual aqueous solution after the irradiation was recovered, and the Cu supported amount was calculated from the difference between the initial copper amount and the recovered copper amount.

Fig. 59 shows the relationship between the Cu loading amount and the bacterial survival rate during light irradiation (L) and dark time (D). From this figure, the following facts can be known.

First, the support of Cu improves the antibacterial properties. Secondly, when light is irradiated (L), when less Cu is supported than when it is dark (D), the antibacterial property is higher. This is because when light is irradiated (L), the photocatalytic action of the rutile-type TiO2 thin film that restores the photoactivity due to Cu support acts. It can be seen from this figure that the addition of 0.12 μg/cm2 or more is ++, and the addition of 0.3 μg/cm2 or more increases to +++.

It is known that Cu itself has an antibacterial effect. Therefore, when the copper load is increased in the dark, it can be seen that the antibacterial property improves. At this time, when the supporting amount is 0.7 μg/cm2 or more, it is ++, and when the supporting amount is 1.2 μg/cm2, it is increased to +++.

Therefore, according to the ++ level evaluation, it is 0.12μg/cm2 or more and 0.7μg/cm2 or less. According to the +++ level evaluation, the Cu loading amount is 0.3μg/cm2 or more and 1.2μg/cm2 or less. (L), it has good antibacterial properties, which can be considered as a special effect produced by the combination of Cu and rutile TiO2 film due to the existence of rutile TiO2 film. The Cu loading amount can be small. In this way, the amount of Cu loading can be reduced, especially when the composite member is used around water, which is an important property. It is used in an environment where copper can be dissolved in water, such as use on sinks in washstands and sanitary ceramics. It can also inhibit the amount of dissolution.

In addition, in the case of Cu, the same effect is obtained in the form of Cu2O. This is because on the surface during photoreduction, monovalent Cu is detected by ESCA, and although Cu2 is partially changed to Cu+, the effect of restoring photoactivity is observed.

On the other hand, by setting the Cu loading amount to 0.7 μg/cm2 or more, preferably 1.2 μg/cm2 or more, good antibacterial properties can be obtained regardless of the presence or absence of light irradiation.

In addition, Fig. 60 shows the relationship between the Cu coating amount and the Cu loading amount when the Cu concentration in the solution is 1% by weight. It can be seen from this graph that even if the Cu coating amount is simply increased, the Cu loading amount is Do not increase, in order to make the copper loading amount 0.7μg/cm2 or more, the Cu coating amount can be 0.2mg/cm2 or more and 2.7mg/cm2 or less, in order to make the Cu loading amount 1.2μg/cm2 As described above, the coating amount of Cu can be 0.3 mg/cm2 or more and 2.4 mg/cm2 or less.

In Example 51, an ammonia dispersion of TiO2 sol with an average particle diameter of 0.01 μm was sprayed on a 15 cm square ceramic tile substrate, and fired at 900° C. to form a rutile TiO2 film with a thickness of 0.8 μm. Next, on the surface of the tile, change the coating amount of the silver nitrate aqueous solution (solution concentration 0.2% (weight), 0.5% (weight), 1% (weight)), apply the solution by spraying, and then perform photoreduction (The light source is a 20W BLB lamp, the distance from the light source to the sample is 10 cm, and the irradiation time is 10 seconds) to obtain a sample. The antibacterial properties of the obtained samples were evaluated. The residual aqueous solution after irradiation was recovered, and the amount of Ag supported was calculated from the difference between the initial amount of silver and the amount of recovered silver.

Fig. 61 shows the relationship between the Ag loading and the bacterial survival rate during light irradiation (L) and dark time (D). The following facts can be clear from this figure.

First of all, unlike the case of Cu, the survival rate curves of bacteria under light irradiation (L) and dark (D) overlap. This is not so much that the presence of Ag does not produce different effects from the case of Cu. It is better to say that the antibacterial activity of Ag is much greater than that of Cu, and the effect is produced with a very small amount of support, so it can be considered as light irradiation (L) The difference between the necessary load and the dark time (D) is included in the results of the experimental error range.

In addition, it can be seen from this figure that by setting the loading amount of Ag to 0.05 μg/cm2 or more, preferably 0.1 μg/cm2 or more, good antibacterial properties can be obtained regardless of the presence or absence of light irradiation.

In addition, FIG. 62 shows the relationship between the supported amount of silver and the color difference of a sample that does not support silver. If the supported amount of silver exceeds 1 μg/cm 2, the color difference rapidly increases and exceeds 2. Generally, if the color difference is 2 or more, the difference in color is significant. If silver is attached, it changes from brown to black, so the appearance is ugly and undesirable. Therefore, it is desirable to control the chromatic aberration to 2 or less. For this reason, the loading amount of silver should be 1 μg/cm2. In addition, the color difference was measured with a spectrophotometer (manufactured by Tokyo Denshoku Co., Ltd.).

However, in the above-mentioned embodiments, in order to prevent the active site of the photocatalyst from being covered with some molecular substances and dust by the surface treatment agent to reduce the chemical ability or restore the activity, it has been described that silver, copper, platinum, Metal particles such as palladium, gold, nickel, iron, cobalt, zinc, etc. cover the active points of the particles with photocatalytic activity, but because such metals are non-ferrous metals, if they are coated in large quantities, they will have inherent colors on the surface of the substrate. , Damage the color, pattern and other patterns of the substrate.

Therefore, the following describes a decolorization method that maintains high photocatalytic activity without damaging the color, pattern, and other patterns of the substrate.

As a basic method, it consists of two processes: a process of fixing metal particles on particles with photocatalytic activity, a process of reacting the above-mentioned metal particles with an aqueous solution or gas, and at least forming a colorless or white salt on the surface of the metal particles. Catalysts containing metal particles.

The order in which the above two processes are carried out is different, but they can be carried out from anywhere. That is, after fixing the non-ferrous metal particles on the photocatalytically active particles, the metal particles can be reacted with an aqueous solution or gas to form at least a colorless or white salt on the surface of the metal particles, or the non-ferrous metal particles can be combined with an aqueous solution or gas. The reaction is carried out, at least after a colorless or white salt is formed on the surface of the metal particles, it is fixed on the particles with photocatalytic activity.

In addition, it is also possible to mix photocatalytically active particles and non-ferrous metal particles and fix them on the substrate. In this case, for example, the following process is carried out sequentially, that is, the photocatalytically active particles and non-ferrous metal particles are mixed. The process is the process of coating the above-mentioned mixture on the substrate, the process of baking the above-mentioned mixture on the substrate, and the process of reacting with the gas to at least form a colorless or white salt on the surface of the metal particles.

Furthermore, the process of baking to fix the above-mentioned mixture on the surface of the substrate and the process of reacting with the gas to form a colorless or white salt on the surface of at least the metal particles may be performed simultaneously.

The so-called non-ferrous metal particles refer to silver, copper, platinum, palladium, gold, nickel, zirconium, cobalt, and zinc particles that have a low ionization tendency and are easily reducible by themselves.

When a colorless or white salt is formed by the reaction of an aqueous solution, or when a metal particle-containing catalyst is used in a liquid, the colorless or white salt formed may be poorly soluble or insoluble.

When the catalyst containing metal particles is fixed on the substrate for use, the particles with photocatalytic activity can be fixed on the substrate in advance and then made into a catalyst containing metal particles, or after making a catalyst containing metal particles, Fixed on the substrate.

In the case of preparing a metal particle-containing catalyst by fixing particles with photocatalytic activity on a substrate in advance, it can be carried out in the following order, that is, the process of forming a layer of particles with photocatalytic activity on the substrate. The process of fixing non-ferrous metal particles on it is a process of covering the above-mentioned non-ferrous metal particles to form a colorless or white salt.

The process of covering the non-ferrous metal particles to form a colorless or white salt is carried out, for example, by reacting with the above-mentioned non-ferrous metal particles to form a colorless or white salt solution at least on the surface of the metal particles and contacting the metal particles, or by contacting the metal particles with the above The reaction of the non-ferrous metal particles is carried out by contacting the metal particles with a reaction gas capable of forming a colorless or white salt at least on the surface of the metal particles.

The white or colorless salt in the salt of the aforementioned non-ferrous metal particles is preferably a poorly soluble or insoluble salt. Therefore, the reaction in an aqueous solution can easily form a salt on the surface of the metal particles at least, and it can be used stably in an environment with water.

The white or colorless salt in the above-mentioned non-ferrous metal particulate salt includes, for example, silver chloride, silver bromide, silver iodide, silver oxalate, silver thiosulfate, silver cyanide, silver thiocyanide, cuprous chloride, Cuprous bromide, cuprous cyanide, cuprous thiocyanide, cuprous oxide, zinc phosphate, zinc oxalate, zinc cyanide, palladium cyanide, zinc sulfide, zinc carbonate, ferrous carbonate, zinc oxide, etc. A solution capable of forming the above-mentioned salt, for example, in the case of silver chloride, potassium chloride solution, sodium chloride solution, ammonium chloride solution, ferrous chloride solution, etc., and in the case of silver iodide, include Potassium iodide solution, sodium iodide solution, ferrous iodide solution, hydrogen peroxide water, ozone water, etc., but not limited to these, any soluble salt solution containing various salt anions can be widely used.

In addition, if the reaction gas capable of forming the above-mentioned salt also contains anion elements of various salts, it can also be widely used. For example, if the above-mentioned salt is an oxide such as zinc oxide and cuprous oxide, it can be oxidized on the surface of the metal particles by heating in air, oxygen, water vapor, or reacting with an oxidant such as O3, and an oxide layer can be formed on the surface .

Specific examples are given below. Example 52 is coated with a titanium oxide sol with an average particle size of 0.01 μm on the surface of a 15 cm square ceramic tile substrate, and then heat-treated at 900° C. to form a rutile titanium oxide thin film. The sample formed up to this stage serves as comparative sample 1.

After that, the silver nitrate aqueous solution was coated by spraying, and irradiated with a 20W BLB lamp as a light source for 10 minutes to fix the silver on the rutile titanium oxide film. At this time, the loading amount of silver was 1.2 μg/cm2, and it was brown. The sample formed up to this stage was used as the comparative sample 2.

After that, a 0.1 mol/L potassium iodide aqueous solution was coated on the comparative sample 2 at a ratio of 0.1 cc/cm 2 and reacted. As a result, the surface of the sample changed to yellowish white, and turned white. It is considered that this is because the silver iodide layer was formed. This sample was used as Example Sample 1.

These samples were evaluated for color difference, light activity, deodorization and antibacterial properties.

The color difference was measured with a spectrophotometer (manufactured by Tokyo Denshoku Co., Ltd.). At this time, the standard sample was used as comparative sample 1. The results are shown in Figure 63. As a result, the chromatic aberration of Comparative Sample 2 was 3.5. On the contrary, the chromatic aberration of Example Sample 1 was reduced to 1, and the degree of color development was reduced due to the treatment with the potassium iodide aqueous solution.

Regarding the photoactivity, it was evaluated by the ΔpH test. The results of photoactivity and deodorization are shown in Fig. 64. By comparing the comparison samples 1 and 2, the photoactivity of the comparison sample 2 is restored due to the silver loading, and both ΔpH and R30(L) show good results. In addition, it is known in comparison between Example Sample 1 and Comparative Sample 2 that both ΔpH and R30 (L) are approximately the same value, and even with the decolorization treatment, the photoactivity does not change, and good characteristics can be maintained.

In addition, the antibacterial properties were tested with Escherichia coli (Escherichia coli W3110 strain). Drop 0.15 ml (2×104 CFU) of bacterial liquid on the outermost surface of the sample pre-sterilized with 70% ethanol, place it on a glass plate (100×100), and adhere to the outermost surface of the substrate as the sample. Wipe with sterile gauze, irradiate the sample (L) with a white light (3500 Lux) for a given time and keep the sample (D) in a darkened condition, and recover the bacteria in 10ml of physiological saline to detect the number of surviving bacteria. Evaluation.

The results regarding the antibacterial properties are shown in Fig. 65. Since the comparative sample 1 does not support silver, the antibacterial effect in the dark time (D) is not seen. On the contrary, in Example 1, although the surface of silver was changed into a compound by the decolorization treatment, the antibacterial effect in the dark time (D) was also seen. In addition, a stronger antibacterial effect was observed during light irradiation (L), and not only the antibacterial effect of silver was observed, but also the photocatalytic activity recovery effect of the rutile titanium oxide film was observed.

Example 53 After coating a glaze on a 15cm square sanitary ceramics shaped blank, it was fired at 1100-1200°C, and then coated with anatase titanium oxide sol with an average particle size of 0.01μm, and fired at 900-1000°C. The rutile titanium oxide film is fixed on the base material of the sanitary ceramic shaped blank.

After that, an aqueous silver nitrate solution was coated thereon, and ultraviolet rays were irradiated to precipitate silver on the titanium oxide film. Then, an aqueous solution of ferrous chloride was coated on it, irradiated with ultraviolet rays to decolorize, and the color difference was reduced from 3 to 0.3. In addition, the antibacterial property was in contact with the sample for 30 minutes during light irradiation and in the dark, and it was confirmed that the number of live bacteria was only 10% or less of the original number of bacteria, showing good results.

Example 54 After coating the glaze on a 15cm square sanitary ceramics shaped blank, it is fired at 1100-1200°C, and then anatase type titanium oxide sol with an average particle diameter of 0.01μm is coated, and it is fired at 900-1000°C. The rutile titanium oxide film is fixed on the base material of the sanitary ceramic shaped body.

After that, a silver nitrate aqueous solution was coated thereon, and ultraviolet rays were irradiated to make silver on the titanium oxide film. The sample was placed in a desiccator with an ozone generator (ozone concentration of 10 ppm) for about 2 hours to decolorize, and it was confirmed that the number of living bacteria was only 10% or less of the original number, showing good results.

Example 55 After coating a glaze on a 15 cm square sanitary ceramics shaped blank, it was fired at 1100-1200°C, and then anatase-type titanium oxide sol with an average particle size of 0.01 μm dispersed in an aqueous nitric acid solution was coated on it The mixture with silver nitrate aqueous solution is then fired to fix the titanium oxide film on the sanitary ceramic formed bad substrate. At this time, if it is fired at 700°C or lower, it will appear brown, but if it is fired at 700°C or higher, it will decolor. It can be explained that the silver surface reacts with the components in the atmosphere. In addition, the antibacterial properties of the sample, which was baked at 850°C and fixed anatase-type titanium oxide film on the base material of the sanitary ceramics, was measured. The sample was contacted with the sample for 3 hours during light irradiation and in the dark, and it was confirmed that the living bacteria were only the original Less than 10% of the number of bacteria showed good results.

Example 56 After coating the glaze on a 15cm square sanitary ceramics shaped blank, it was fired at 1100-1200°C, and then anatase type titanium oxide sol with an average particle size of 0.01μm was coated on it at 900-1000°C Firing, fixes the rutile titanium oxide film on the sanitary ceramic formed bad substrate.

Then, an aqueous silver nitrate solution was coated on it, and ultraviolet rays were irradiated to precipitate silver on the titanium oxide film. Then apply hydrogen peroxide water on it to decolorize it. In addition, the antibacterial property was in contact with the sample for 3 hours both during light irradiation and in the dark, and it was confirmed that the number of living bacteria was only 10% or less of the original number of bacteria, showing good results.

Next, the problem of mixing rutile-type TiO2 particles and tin oxide in order to improve the compactness and adhesion of the photocatalyst film and at the same time increase the activity will be described.

As a method of forming the photocatalyst thin film, either of the following two methods can be used.

One is to mix TiO2 sol and tin oxide sol in advance, and coat them on the surface of the substrate for baking.

The mixing of TiO2 sol and tin oxide sol is carried out in an alkaline aqueous solution. Both of them showed good dispersion because of the alkaline side from the electrochemical point of view. Examples of the alkaline aqueous solution include ammonia and hydroxides containing alkali metals or alkaline earth metals. However, ammonia is particularly preferred from the viewpoint of not generating metal contaminants after heat treatment. In addition, an organic type, phosphoric acid type dispersant, surface treatment agent, and surfactant may be further added to these dispersion liquids.

As the coating method, there are methods of forming a coating film by spraying, dipping, roll coating, spin coating, CVD, electron beam evaporation, sputtering, etc. of the above-mentioned mixed solution, but it may be any of these methods, or it may be Other methods besides this. However, spray coating, dipping, and roll coating have the advantage of not requiring special equipment and forming a coating film at a low cost compared to CVD, electron beam evaporation, and sputtering.

After coating, the film can be dried before firing. Drying can be carried out at room temperature-about -100°C.

The calcination is carried out at a temperature sufficient to generate rutile. This temperature is 830°C or higher when coexisting with tin oxide under normal pressure.

It is not necessary to form a solid solution of TiO2 and tin oxide. In order to form a solid solution of TiO2 and tin oxide, it needs to be maintained at a high temperature for a long time, so the production efficiency becomes low.

Another method is to form a rutile TiO2 thin film, add tin oxide sol on it, and then calcinate it.

This method first coats Ti-containing starting materials on the substrate. Here, TiO2 sol, titanium alkoxide, Ti sulfate, Ti chloride solution, etc. are used as starting materials. In the case of using TiO2 sol, the isoelectric point of TiO2 is pH 6.5, which is almost neutral. Therefore, it is easy to coat evenly by using an acid or alkali-dispersed aqueous solution to coat the substrate. When the base material is a metal at this time, an alkali dispersion is preferable from the viewpoint of corrosion resistance. In the case of ceramics, tiles, ceramics, etc., any dispersion liquid of acid or alkali can be used. Examples of the acid include nitric acid, sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, and organic acids. Examples of the alkaline aqueous solution include ammonia and hydroxides containing alkali metals or alkaline earth metals, but ammonia is particularly preferred from the viewpoint that metal contaminants are not generated after heat treatment. In addition, organic or phosphoric acid-based dispersants, surface treatment agents, and surfactants may be further added to these dispersion liquids. In addition, the average particle size of the starting material TiO2 sol may be 0.05 μm or less, preferably 0.01 μm or less. If the particle size is small, initial sintering occurs at a lower temperature, so a photocatalyst film with excellent peel strength can be produced at a low temperature. The method of coating on the substrate can be spray coating, dip coating, roll coating, spin coating, CVD, electron beam evaporation, sputtering and other methods to coat these dispersions. It can be any of these methods, or it can be Other methods besides this. However, spraying, dipping, and roll coating have the advantage of not requiring special equipment and forming a coating film at low cost compared to CVD, electron beam evaporation, sputtering, etc. After coating, it can be dried before firing. Drying can be carried out at room temperature-about -100°C.

The coated composite member is then fired. Roasting is carried out at a temperature at which rutile is formed. This temperature is 900°C or higher under normal pressure.

After that, the cooled and solidified composite member is coated with the starting material that becomes the Sn source and fired. As the starting material for the Sn source, there are tin oxide sol and the like. An alkaline aqueous solution can be used in the tin oxide sol. This is because tin oxide sol is stable on the alkali side from an electrochemical point of view. Examples of the alkaline aqueous solution include ammonia and hydroxides containing alkali metals or alkaline earth metals, but ammonia is particularly preferred from the viewpoint that metal contaminants are not generated after heat treatment. In addition, an organic or phosphoric dispersant, a surface treatment agent, and a surfactant may be further added to these dispersion liquids. The method of coating on the substrate can be spraying, dipping, roll coating, spin coating, CVD, electron beam evaporation, sputtering, etc. to apply these dispersions to form a coating film, and it can be any of them. , It can also be other methods besides this. However, spray coating, dipping, and roll coating have the advantages of requiring no special equipment and being able to form a coating film at a low cost compared to CVD, electron beam evaporation, and sputtering. After coating, it can be dried before firing. Drying is preferably carried out at room temperature-about -100°C. The firing temperature may be the temperature at which organic additive components are evaporated from tin oxide. This temperature is 300°C or higher under normal pressure. In addition, it is not necessary to form a solid solution of TiO2 and tin oxide. In order to form a solid solution of TiO2 and tin oxide, it is necessary to maintain a high temperature for a long time, and thus the production efficiency becomes low.

In addition, a thin film composed of a mixture of rutile TiO2 and tin oxide with a crystal grain size of 0.01 μm or less is formed on the surface of the substrate, and Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu2O can be fixed on it. At least one metal.

These metals have an electron-trapping effect, and use this to improve the photocatalytic activity of a thin film composed of a mixture of rutile TiO2 and tin oxide with a crystal particle size of 0.01 μm or less.

In particular, Cu and Ag themselves have antibacterial activity and can impart dark activity related to antibacterial properties, so it is possible to maintain a certain degree of antibacterial activity even if they are not irradiated. The method of fixing at least one metal among Cu, Ag, Pt, Fe, Co, Ni, Pd, and Cu2O is to coat at least one metal salt aqueous solution among these metals, and then fix it by a photoreduction method or a heat treatment method.

In the metal salt aqueous solution, the metal basically dissolves as a cation. Specific examples include copper acetate, silver nitrate, copper carbonate, copper sulfate, cuprous chloride, copper chloride, chloroplatinic acid, palladium chloride, nickel chloride, cobalt chloride, ferrous chloride, and ferric chloride Wait.

The coating method of the metal salt aqueous solution includes spraying or dipping. However, the spraying method is more ideal because it can be used in a small amount, uniformly coated, easy to control the film thickness, and can not adhere to the back as needed.

In the case of the photoreduction method, light containing ultraviolet rays is then irradiated to reduce metal ions, and Cu, Ag, Pt, Fe are fixed on a thin film composed of a mixture of rutile TiO2 and tin oxide with a crystal particle size of 0.01 μm or less , Co, Ni, Pd, Cu2O at least one metal.

The light source for irradiating ultraviolet light may be a light source capable of irradiating ultraviolet light, and specifically may be any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, and the like. In the method of irradiating ultraviolet light, it is desirable to arrange the sample so that the light is perpendicular to the irradiated surface. Because the irradiation efficiency is the best. The ideal distance from the light source to the sample is 1cm-30cm. If the distance is too short, the light cannot be irradiated with approximately equal illuminance on the entire sample surface. The adhesion of the above-mentioned metal species is prone to deviation, and the distance is too long because the illuminance of the irradiated light decreases inversely proportional to the square of the distance. Therefore, it is difficult to firmly adhere the metal species.

In the heat treatment method, in order to fix the metal thereafter, it is heated to a sufficient temperature for fixation. The temperature is preferably 100°C or higher. However, for example, when the treatment is performed at a so-called high temperature of 800° C. or higher, the metal is oxidized. Therefore, in this case, it is limited to a metal that does not lose the electron trapping effect or loses antibacterial properties even if oxidized. That is, it should be limited to Ag and Cu. In the case of Ag and Cu, the electron trapping effect and antibacterial properties are not lost even when baked at high temperatures, so the following manufacturing methods are also acceptable. That is, TiO2 sol and tin oxide sol are mixed in advance, coated on the surface of the substrate, and then coated with a metal salt aqueous solution and then baked. According to this method, the firing process can be completed at one time, which has the effect of improving productivity and reducing manufacturing costs.

Specific examples are listed below. In Example 55, 4-6% by weight of TiO2 sol with a crystal particle size of 0.01 μm is added to an aqueous ammonia solution adjusted to pH 11 to form a suspension A. In another container, 10% by weight of tin oxide sol with a crystal particle size of 0.0035 μm was added to the ammonia solution adjusted to pH 11 to prepare suspension B. After mixing Suspension A and Suspension B in a given ratio, they were sprayed on the surface of a 15 cm square ceramic tile substrate, dried and fired at 850°C for 2 hours to obtain a sample. The crystalline type of TiO2 in the obtained sample is rutile. In addition, the lattice constant was measured by powder X-ray diffraction, and there was no solid solution of tin oxide into the TiO2 crystal lattice. The photoactivity and abrasion resistance of the obtained samples were evaluated.

Regarding the photoactivity, an aqueous potassium iodide solution was dropped on the surface of the sample, and then the dropped potassium iodide aqueous solution was irradiated with ultraviolet rays for 30 minutes, and the difference between the pH of the potassium iodide aqueous solution before the irradiation and the potassium iodide aqueous solution after the irradiation was evaluated. That is, according to this method, if the photoactivity of the sample surface increases, the oxidation-reduction reaction shown below proceeds more easily, so the pH after irradiation is higher than the pH before irradiation.

Oxidation reaction: reduction reaction: In addition, plastic rubber is used for sliding friction for abrasion resistance, and the changes in appearance are compared and evaluated. The evaluation indexes , , , and × are the same as above.

Fig. 66 shows the change in wear resistance relative to the weight ratio of tin oxide in the film. Regardless of the presence or absence of tin oxide, the abrasion resistance showed good results, being or . It is considered that the treatment at a so-called high temperature of 850°C caused sintering and the particles in the film were firmly bonded to each other.

In particular, when tin oxide exceeds 30%, it is . This is because the particle size ratio of the starting material TiO2 sol (crystal particle size 0.01μm) and tin oxide (crystal particle size 0.0035μm) is 2 or more, and the fine tin oxide particles fill the gaps between the TiO2 particles to improve the filling ability and the film For dense.

Fig. 67 shows the change in photoactivity relative to the weight of tin oxide in the thin film. For comparison, the pH of a sample (60% at R30) supported by Cu on rutile TiO2 showing good antibacterial and deodorant properties and anatase TiO2 showing very good antibacterial and deodorant properties are also shown. The delta pH of the sample (97% at R30). The pH of rutile TiO2 added with tin oxide is not as good as that of anatase TiO2, and the weight ratio of tin oxide is more than 10%, 80% or less, or 20% or more, 70% or less, and the rutile TiO2 is loaded with Cu. The pH shows a larger value and has good photoactivity.

The addition of tin oxide with an average particle diameter of 0.01 μm or more does not increase the photocatalytic activity. This is because the position of the conductive band is not moved up enough due to the micronization of tin oxide, and the tin oxide particles do not have a band gap sufficient to generate active oxygen. In addition, if it does not exceed 10%, sufficient photoactivity is not produced, which is caused by the insufficient amount ratio of tin oxide particles. On the other hand, the effect is weak at 80% or more. This is because the probability of adjacent presence of tin oxide in the photocatalyst layer increases. Therefore, it is estimated that the frequency of particles growing to an average particle diameter of 0.01 μm or more during heat treatment increases.

In Comparative Example 56, 4-6% by weight of a TiO2 sol with a crystal particle size of 0.01 μm was added to an aqueous ammonia solution adjusted to pH 11. Prepare suspension A. In another container, 10% by weight of tin oxide sol with a crystal particle size of 0.01 μm was added to the ammonia solution adjusted to pH 11 to prepare suspension B. After mixing Suspension A and Suspension B in a given ratio, they were sprayed on the surface of a 15 cm square ceramic tile substrate, dried and then calcined at 850°C for 2 hours to obtain a sample. The crystalline type of TiO2 in the obtained sample is rutile. The lattice constant of TiO2 was measured by powder X-ray diffraction, and there was no solid solution of tin oxide into the TiO2 lattice. The photoactivity and abrasion resistance were evaluated on this sample.

FIG. 68 shows the change in wear resistance with respect to the weight ratio of tin oxide in the film. Regardless of the presence or absence of tin oxide, the abrasion resistance showed good results, which was . It is considered that sintering occurs at a so-called high temperature of 850°C, and the particles in the film are firmly bonded to each other. However, even if the amount of tin oxide added was increased this time, the wear resistance could not be improved. It is considered that this is because the particle size ratio of the starting material TiO2 sol (crystal particle size 0.01 μm) and tin oxide sol (crystal particle size 0.01 μm) is approximately equal.

Fig. 69 shows the change in photoactivity with respect to the weight ratio of tin oxide in the thin film. For comparison, the ΔpH of the sample containing Cu supported on the rutile TiO2 exhibiting good antibacterial and deodorizing properties and the ΔpH of the anatase TiO2 sample exhibiting very good antibacterial and deodorizing properties are also shown. . The ΔpH of the rutile TiO2 with tin oxide added is far inferior to the ΔpH of the anatase TiO2 sample this time, and it is also far inferior to the ΔpH of the sample containing Cu on the rutile TiO2.

In Example 57, 4-6% by weight of TiO2 sol with a crystal particle size of 0.01 μm was added to an ammonia solution adjusted to pH 11 to prepare suspension A. In another container, 10% by weight of tin oxide sol with a crystal particle size of 0.0035 μm was added to the ammonia solution adjusted to pH 11 to prepare suspension B. After mixing Suspension A and Suspension B in a given ratio, they are sprayed on the surface of a 15 cm square ceramic tile substrate, dried and fired at 850° C. for 2 hours to obtain a composite component. The crystalline type of TiO2 in the obtained composite structure is rutile. And the weight ratio of tin oxide in the film is 60%. In addition, the lattice constant of TiO2 was measured by powder X-ray diffraction, and there was no solid solution of tin oxide into the TiO2 lattice. After coating the composite member with a 5% (weight) copper acetate aqueous solution by spraying, it is dried and then photoreduced (the light source is a 20W BLB lamp, the distance from the light source to the sample is 10cm, and the irradiation time is 1 minute. ), get the sample. The deodorant property R30 was evaluated for the obtained sample.

Here, R30 is determined by the experiment shown below. Methyl mercaptan is used in the decomposition gas, and the sample is set in a cylindrical container with a diameter of 26 cm and a height of 21 cm, with the initial concentration of methyl sulfuric acid adjusted to 2 ppm. A 4W BLB fluorescent lamp was placed 8 cm away from the sample, and light was irradiated for 30 minutes, the concentration reduction rate of methyl mercaptan was calculated, and the deodorization R30 (L) during light irradiation was obtained. In addition, the concentration reduction rate of methyl mercaptan after 30 minutes has passed without light irradiation was calculated, and the deodorant property R30 (D) in the dark was obtained. The results are shown in Table 26. For comparison, the samples prepared in Example 55 and Comparative Example 56 (the weight ratio of tin oxide is 60%) were simultaneously tested. It is clear from Table 26 that the addition of Cu has the following effects. (Table 26)

(The weight ratio of SnO2 is both 60%) It can be seen from Table 26 that compared with the sample of Example 53, R30(L) has a certain increase. It is considered that this is caused by the electron trapping effect of Cu. In addition, compared with Example 53 and Comparative Example 54, R30 (D) was significantly improved. This increase in dark activity can be explained by the catalytic effect of copper.

It can be seen from the above description that in the member in which the photocatalyst thin film is formed on the surface of the substrate, the TiO2 component of the photocatalyst thin film is treated at the calcination temperature at which the TiO2 component of the photocatalyst thin film becomes rutile, and sufficient compactness and TiO2 film strength can be maintained. At this time, in addition to rutile TiO2, if tin oxide with a crystal particle size of 0.01 μm or less is present, the photocatalytic activity of the photocatalyst thin film can be improved.

Then, at least one metal of Cu, Ag, Pt, Fe, Co, Ni, and Pd is fixed on the photocatalyst film, and the electron trapping effect can be used to further improve the photocatalytic activity.

Industrial Applicability As described above, the multifunctional material of the present invention with antibacterial, antifouling, deodorizing and photocatalytic functions for decomposing harmful substances such as NOx is suitable for wall materials, tiles, glass, mirrors, and as a circulating filter device For example, artificial waterfalls and water-spraying stones used for paving stones, or sanitary ceramics such as toilets and washstands, hospital equipment used to prevent bacterial infections such as MRSA, residential equipment, anti-fungal equipment, and anti-viral infection equipment Wait.