Multi-functional material with photo-catalytic functions and method of manufacturing same

Multifunctional material having photocatalytic function and manufacturing method thereof

[Brief Description of Drawings]

1a is a conventional TiO₂ It is a view showing the state before sintering, and FIG. 1B is a view showing the state after rutile type sintering.

Figure 2a is a conventional TiO₂ It is a figure which shows the state before sintering of particle|grains, and FIG. 2B is a figure which shows the state after sintering.

3 is a view schematically showing a state in which photocatalyst particles constituting a photocatalyst layer among multifunctional materials having a photocatalytic function according to the present invention are combined by mutual potential energy.

4 is a view schematically showing a state in which the photocatalyst particles constituting the photocatalyst layer among the multifunctional materials are bonded to each other by solid-state sintering.

5 is a view schematically showing a state in which small particles are filled in the gap formed between the photocatalyst particles constituting the photocatalyst among the multifunctional materials.

6 is a view schematically showing a state in which metal particles are immobilized on the surface of the photocatalytic particles of the multifunctional material shown in FIG. 3 .

7 is a view schematically showing a state in which metal particles are immobilized on the surface of the photocatalytic particles of the multifunctional material shown in FIG. 4 .

8 is a view 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 .

9 is a view schematically illustrating a state in which a photocatalyst layer is bonded to a substrate through a binder layer among the multifunctional materials, and photocatalyst particles constituting the photocatalyst layer are coupled by mutual potential energy.

10 is a view schematically showing a state in which a photocatalyst layer is bonded to a substrate through a binder layer among the multifunctional materials, and photocatalyst particles constituting the photocatalyst layer are bonded to each other by solid-state sintering.

11 is a diagram schematically illustrating a state in which a photocatalyst layer is bonded to a substrate through a binder layer among the multifunctional materials, and small particles are filled in the gaps formed between the photocatalyst particles.

12 is a view schematically showing a state in which metal particles are immobilized on the surface of the photocatalytic particles of the multifunctional material shown in FIG. 9 .

13 is a view schematically showing a state in which metal particles are immobilized on the surface of the photocatalytic particles of the multifunctional material shown in FIG. 10 .

14 is a view schematically showing a state in which metal particles are immobilized on the surface of the photocatalytic particles of the multifunctional material shown in FIG. 11 .

15 is a view for explaining a method of manufacturing a multifunctional material having a photocatalytic function according to the present invention.

16a and 16b show TiO₂ It is an enlarged view between particles.

17a to 17c show TiO₂ It is a figure explaining the mechanism of particle sintering.

18 is a graph showing the test results for the antimicrobial test.

19 is a graph comparing the test results for the Cu loading amount in the case where the drying process was put before irradiation with the BLB lamp and when the drying process was not added.

20 is a graph showing the relationship between the amount of Cu supported and the amount of Cu applied.

21 is a view showing a manufacturing process of a multifunctional material having photocatalytic activity according to a separate embodiment.

22 is a graph showing the test results for the antimicrobial test.

23 is a graph comparing test results with respect to the amount of Cu supported in the case where the drying process was put before irradiation with the BLB lamp and when not put.

24 is a graph showing the relationship between the amount of Cu supported and the amount of Cu applied.

25 is a graph showing the relationship between the Ag loading amount and the bacterial viability.

26 is a conceptual diagram of a basic profile when the cross-sectional direction of the multifunctional material is observed with an EBMA (electron beam microanalyzer).

27 is a conceptual diagram of a basic profile when the cross-sectional direction of the multifunctional material is observed with an EBMA (electron beam microanalyzer).

28 shows TiO₂with SnO₂It is a graph showing the relationship between the formulation of , film strength, and photoactivity.

29 is a graph showing the relationship between heat treatment temperature and photoactivity.

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

31 is a view for explaining a method for measuring the activity of a photocatalyst thin film.

32 is a view for explaining a method for measuring the activity of a photocatalyst thin film.

33 is a graph showing the relationship between the UV irradiation time and the amount of change in pH.

34 shows R₃₀It is a graph showing the relationship between and the amount of change in pH.

35 shows porosity and deodorization (R₃₀) and a graph showing the relationship between wear resistance.

36 shows the film thickness and deodorization (R₃₀) is a graph showing the relationship between

37 shows the film thickness and deodorization (R₃₀) and a graph showing the relationship of peel resistance.

38 is SnO₂ Addition amount and deodorization (R₃₀) and a graph showing the relationship between wear resistance.

39 is SnO₂ It is a graph showing the relationship between the amount of addition and the difficulty of adhesion of contamination.

40 is SnO₂ Addition and TiO₂It is a graph showing the relationship between the open porosity of the layer surface.

41 is SnO₂ Addition and TiO₂It is a graph showing the relationship between the open pore width of the layer surface.

42 is SnO₂ Addition amount and deodorization R₃₀ (L) is a graph showing the relationship between and peel resistance.

43 is a graph showing the relationship between the number of coatings and the difficulty of contamination adhesion.

44 is a graph showing the relationship between the number of coatings and abrasion resistance.

45 shows the number of coatings and TiO₂It is a graph showing the relationship between the open porosity of the layer surface.

46 is a view showing a state in which the photocatalyst particles are exposed to the outside air by preferentially decomposing and vaporizing the soft curable resin on the photocatalyst particles by irradiating ultraviolet rays.

Fig. 47 is the same view as Fig. 46 showing another embodiment.

Fig. 48 is the same view as Fig. 46 showing another embodiment.

49A and 49B are diagrams illustrating a state in which small particles are filled in the gaps between the photocatalyst particles.

50 is a rutile-type TiO₂It is a block diagram showing the manufacturing process of a multifunctional material using

51 is a graph showing the relationship between Cu solution concentration and photoactivity in the case of photoreduction by drying the Cu solution.

52 is a graph showing the relationship between the Cu solution concentration and photoactivity in the case of photoreduction without drying the Cu solution.

53 is a rutile-type TiO₂ Cu dissolution concentration and odor removal rate R when the metal to prevent in the thin film is Cu₃₀is a graph showing the relationship (reduction of metal ions is performed after drying the aqueous metal salt solution).

54 shows the substrate as a wall tile, and rutile-type TiO₂ Cu dissolution concentration and odor removal rate R when the metal supported on the thin film is Cu₃₀A graph showing the relationship between (reduction of metal ions is carried out after drying the aqueous metal salt solution).

55 is a rutile-type TiO₂ Odor removal rate R after calcination temperature and Cu fixation to form a thin film₃₀is a graph showing

56 is a graph showing the relationship between the dissolution concentrations of Ag and Cu and the color difference.

57 shows porosity and R₃₀ and a graph showing the relationship between wear resistance.

58 is a graph showing the relationship between the amount of copper supported and the bacterial viability.

59 is a graph showing the relationship between the amount of copper applied and the amount of copper supported.

60 is a graph showing the relationship between the amount of silver supported and the bacterial viability.

61 is a graph showing the relationship between the amount of silver supported and the color difference.

62 is a graph showing the effect of decolorization treatment with KI aqueous solution.

63 shows the pH change and the odor agent ratio R of the KI aqueous solution before and after decolorization with the KI aqueous solution.₃₀ It is a graph showing the relationship of change.

64 is a graph comparing the antibacterial action.

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

66 is a graph showing the photoactivity with respect to the weight ratio of tin oxide in the thin film.

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

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

69 is a graph showing the relationship between the amount of silver supported and the survival rate.

The present invention relates to a multifunctional material exhibiting functions such as a deodorizing function, an antibacterial function, a sterilizing function, and a contamination preventing function, and a method for manufacturing the same.

Conventionally, TiO is a substance that exhibits the function of accelerating decomposition (oxidation) by adsorption or desorption of oxygen molecules to organic compounds such as odor components by irradiating ultraviolet rays.₂, V₂O₅, ZnO, WO₃ etc. are known, and in particular, the crystalline form is anatase TiO₂ Since particles are highly effective as photocatalysts, conventionally, it has been proposed to form a photocatalyst layer on the surface of wall materials, tiles, glass (mirrors), circulation filters, or sanitary ware.

As a method of forming the photocatalyst layer, TiO is directly applied to the surface of a substrate such as plastic, ceramic, or resin by CVD, sputtering, electron beam deposition, or the like.₂ A method of forming a photocatalyst layer made of particles or the like is known.

However, when a CVD method, a sputtering method, an electron beam vapor deposition method, etc. are used, a facility becomes large-scale, and since a yield is bad, manufacturing cost also becomes high.

In addition, as another method of forming the photocatalyst layer, the photocatalyst particles are kneaded with a binder and applied to the surface of the substrate by a spray coating method, or a method of immersion coating by a dip coating method, followed by heat treatment (Japanese Patent Application Laid-Open No. 5-201747 No. publication) is known.

However, TiO₂ In order for photocatalyst particles such as particles to exert their effects as photocatalysts, it is necessary that the photocatalyst particles be irradiated with ultraviolet light or that the photocatalyst particles should come into contact with substances to be decomposed such as odor gas. When photocatalyst particles are kneaded with a binder and applied to the substrate as in the publication, many photocatalysts are buried in the binder layer, so that ultraviolet rays cannot reach them or they do not come into contact with odorous gases, etc.

Also, as another method for forming the photocatalyst layer, the alkoxide method disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 5-7394 is known. In this method, a titanium alkoxide is coated on a glass substrate, dried and then fired at several 100°C to form a photocatalyst layer, and the photocatalyst layer is irradiated with ultraviolet rays to decompose organic matter in water.

The alkoxide method is excellent in forming a thin film at a relatively low temperature and is effective when a substrate that is difficult to soften up to about 500° C., such as Pyrex glass or quartz glass, is used as the raw material. For example, soda glass has a low melting point. In the case of using a material as a substrate, since the photocatalyst thin film that has already started to soften at the temperature at which the thin film is formed and the formed photocatalytic thin film is buried in the substrate, light does not reach the photocatalyst layer, so that the photocatalytic function cannot be exhibited.

In addition, in Japanese Patent Application Laid-Open No. 1-288321, TiO₂ After spraying the sol on ceramic paper, which is a fibrous material, and heat-treating it at 400~700°C, SnO₂ The sol is sprayed and heat-treated at 400°C to 700°C to form a photocatalytic film capable of enhancing the oxidative decomposition of aldehydes.

In the method disclosed in Japanese Patent Laid-Open No. 1-288321, TiO₂SnO with less activity₂to cover the entire surface of the film. In addition, cracks are likely to occur when the film strength is to be increased. That is, as shown in Fig. 1a, TiO on the surface of the tile 100₂ When the sol containing the particles 101 is applied and heat-treated (sintered), cracks 102 are generated as shown in FIG. 1B . The cause is that, as shown in Fig. 2a, TiO before sintering, in addition to causing volume shrinkage (density becomes high) due to the phase transition to the rutile type.₂The spacing between (101) was Lo, but after sintering in the rutile type, the volume was diffused to the other side as shown in FIG. 2b, and the spacing between particles was L₁(L₁<Lo), it is considered that cracks occur.

On the other hand, in the Japanese Patent Application Laid-Open No. 4-46609, a method for purifying an automobile interior odor by decomposing or reforming odor substances contained in odors in the air of automobiles, About a method for purifying a car interior odor, characterized in that the photocatalyst is irradiated with light and the photocatalyst is brought into contact with the indoor air to be purified, thereby decomposing or reforming odor substances contained in the odor in the air through a photochemical reaction has been disclosed.

However, when a substrate coated with a photocatalyst on the surface of the substrate is used in an environment such as in sewage water or an external wall, dirt is easily attached to the substrate by polymers, dust, fungi, etc. contained in the air or water, and depending on the type of soil may deteriorate the photocatalytic function due to the adhesion of the dirt.

[0003] Conventionally, as a countermeasure for the deterioration of the photocatalytic function due to the adhesion of dirt, there is Japanese Patent Laid-Open No. 6-7905. The Japanese Patent Publication No. 6-7905 discloses that a photocatalyst layer or a heating element, or a photocatalyst layer and a heating element, is made of a semiconductor photocatalyst layer and an ultraviolet light installed against it, a heating element and a blower, and the photocatalyst layer or heating element, or the photocatalyst layer and the heating element are moved so that the entire photocatalyst layer is sequentially heated. Disclosed is a deodorizing device using a photocatalyst, and by heating to around 400°C, contamination by polymers, dust, etc. is removed and the photocatalyst layer is regenerated.

However, in such a method by photocatalyst regeneration, it is practically difficult to do this with respect to a member used as a facility attached to a room. Accordingly, there is a need for a fundamental solution to prevent the contamination from adhering to the photocatalyst layer, rather than being removed, and rather preventing the contamination from adhering to the photocatalyst layer or reducing the photocatalytic function due to the adhesion of the contamination.

In addition, Japanese Patent Application Laid-Open No. 6-7906 discloses a method for removing odors in a home or office by irradiating a photocatalyst with light with strong ultraviolet intensity. However, the rate of decomposition of odors differs depending on the structure of the photocatalyst when irradiated with light with strong ultraviolet intensity. In addition, in the preceding example, since the substrate is porous, sufficient mechanical strength can be obtained by methods such as impregnation.

Also, TiO₂There are different crystalline forms of anatase type, bluekite type and rutile type, and for photocatalysts, the anatase type is excellent, and in the case of other crystal types, the photoactivity is not so great. However, rutile-type TiO₂It is also reported in the magazine 1987, vol 25 that the photoactivity is improved by supporting metals such as Pt and Ag, but it is not sufficient in terms of odor removal rate, compactness and adhesion. In particular, when Ag or AgO is used as an additive metal, they cannot be used for tiles or building materials because they are black.

In addition, since the titanium oxide sol produced by the hydrothermal method or the sulfuric acid method becomes ultrafine particles, it is easy to aggregate. When the aggregate is applied to the surface of the substrate, it causes gloss unevenness and cracks. For this reason, conventionally, in order to prevent aggregation, a method of attaching an organic decomposing agent such as triethanolamine to the surface of the titanium oxide sol has been taken.

However, in the method of attaching an organic dispersant such as triethanolamine to the surface of a titanium oxide sol, monodispersed titanium oxide sol is applied to a substrate having low heat resistance, such as a resin substrate, and calcined at less than 300° C., the activity of the titanium oxide sol Since the organic dispersant is firmly fixed to the point and is not sufficiently evaporatively decomposed even in the firing step, the member thus obtained does not have sufficient photocatalytic action and does not have sufficient deodorization or antibacterial properties.

In addition, Japanese Patent Laid-Open No. Hei 5-253544 discloses a method of kneading anatase-type titanium oxide with a binder, coating it on the surface of a substrate, and heat-treating it. In this method, a binder layer is formed on the surface of a plate-shaped member constituting the wall, floor, or ceiling surface of a residential space, and a fine photocatalyst powder mainly composed of anatase-type titanium oxide is applied to the surface of the binder layer, a part of which is separated from the binder layer. It is blow-attached so as to be exposed, and then the binder layer is melted by heating in a range of 300°C or more and less than 900°C, followed by cooling to solidify the binder layer.

However, in this method, heat treatment at 300°C or higher and lower than 900°C has good deodorization properties, but good deodorization properties are not obtained at low temperatures below 300°C. Therefore, it was difficult to add good photocatalytic activity, such as excellent deodorizing properties, to a base material such as a plastic without heat resistance. For this reason, in order to uniformly apply the photocatalyst particles to the substrate, it is necessary to monodisperse the photocatalyst microparticles in the suspension in the previous process. It is thought that this is because it does not vaporize and remains so that the active site on the photocatalyst particle may be covered.

Accordingly, an object of the present invention is to provide a multifunctional material that can sufficiently exhibit the photocatalytic effect by exposing the photocatalyst layer from the substrate and is excellent in maintaining the photocatalyst layer by the substrate.

Another object of the present invention is to form a photocatalyst layer that is difficult to peel off on a relatively dense substrate such as glass, tile, metal, or plastic.

Another object of the present invention is to form a photocatalyst layer on a low-melting-point substrate, such as soda glass, which is inexpensive and easy to process.

In addition, an object of the present invention is to provide a multifunctional material that does not adhere to contaminants, has antibacterial or deodorant properties that can prevent deterioration of functions due to contamination, and has excellent mechanical strength.

In addition, the present invention is anatase-type TiO₂An object of the present invention is to provide a multifunctional material with excellent peel strength even in a photocatalyst layer mainly composed of

In addition, the present invention is rutile-type TiO₂It aims to improve the photocatalytic activity of the photocatalyst layer mainly composed of

In addition, the present invention is rutile-type TiO₂The purpose is to improve the photocatalytic activity by supporting Ag on the photocatalyst layer mainly composed of

Another object of the present invention is to provide a multifunctional material having good photocatalytic function even at low temperature heat treatment of less than 300°C.

The multifunctional material according to the invention is one in which a photocatalyst layer is formed directly or through a binder layer on the surface of a substrate such as ceramics, resin, metal, wood, etc., such as tiles, sanitary ware, and glass. The type, particle size, gap formed between the photocatalyst particles, porosity, the relationship between the binder layer and the photocatalyst layer, the particles filled in the gap between the photocatalyst particles, and the metal particles immobilized on the surface of the photocatalyst particles, etc. are studied and deodorized by these It is made as a multifunctional material which is excellent not only in the effect as a photocatalyst of a photocatalyst layer, such as, but also in antibacterial and abrasion resistance.

<u>best mode for carrying out the invention</u>

In order to explain the present invention in more detail, it will be described with reference to the accompanying drawings.

3 to 14 show the structure of the multifunctional material having a photocatalytic function according to the present invention divided by type, and the multifunctional material having a photocatalytic function according to the present invention belongs to any one structure.

That is, in the multifunctional material shown in FIG. 3 , a photocatalyst layer 2 having a photocatalytic function is directly installed on the surface of the substrate 1 , and the photocatalyst layer 2 has a fine photocatalyst particle 3 that has mutual surface energy or a curved surface. It is constituted by combining with potential energy such as energy.

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

In the multifunctional material shown in FIG. 5, the photocatalyst layer 2 having a photocatalytic function is directly installed on the surface of the substrate 1, and the photocatalyst particles constituting the photocatalyst layer 2 are formed in the gap between the 3, Particles 4 smaller than the gap are filled, and the photocatalyst particles 3 are coupled to each other through the small particles 4 to form a structure.

5 shows a structure in which the particles 4 are filled up to the internal gaps, however, the particles 4 may be filled at least in the gaps between the photocatalyst particles 3 in the surface layer. That is, in the mechanical strength of the photocatalyst layer, since the transmission of external force decreases from the inside, the bonding of the surface is considered to be important. However, in this case, the average particle diameter of the photocatalyst particles is preferably 0.04μm in order to obtain sufficient strength of the photocatalyst layer by binding the photocatalyst particles inside by potential energy.

In the multifunctional material shown in FIG. 6 , the photocatalyst particles 3 constituting the photocatalyst layer 2 formed directly on the surface of the substrate 1 are coupled by mutual potential energy, and Ag, Cu on the surface of the photocatalytic particle 3 , Cu₂Electron trapping particles 5 such as O are immobilized.

In the multifunctional material shown in FIG. 7 , the photocatalyst particles 3 constituting the photocatalyst layer 2 formed directly on the surface of the substrate 1 are bonded to each other by solid-state sintering, and Ag or Pt on the surface of the photocatalyst particles 3 Metal particles 5 of the back are immobilized.

In the multifunctional material shown in FIG. 8, a photocatalyst layer 2 having a photocatalytic function is provided directly on the surface of the substrate 1, and this photocatalyst layer 2 is formed in the gap formed between the photocatalytic particles 3 constituting this gap. Smaller particles 4 are filled, photocatalyst particles 3 are bonded to each other through small particles 4, and metal particles 5 such as Ag and Pt are immobilized on the surface of photocatalyst particles 3 has been

In the multifunctional material shown in Fig. 9, a photocatalyst layer 2 having a photocatalytic function is installed on the surface of the substrate 1 via a binder layer 6, and this photocatalyst layer 2 is exposed to the outside and at the same time, The lower layer is embedded in the binder layer 6, and the surface layer is composed of fine photocatalyst particles 3 coupled by mutual potential energy.

In the multifunctional material shown in FIG. 10, a photocatalyst layer 2 is provided through the same binder layer 6, and the surface layer of the photocatalyst layer 2 consists of photocatalyst particles 3 bonded to each other by solid-state sintering. .

In the multifunctional material shown in FIG. 11, the photocatalyst layer 2 is installed on the substrate 1 through the binder layer 6, and in the gap formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 Particles (4) smaller than the gap are filled, and the photocatalyst particles (3) are bonded to each other through these small particles (4).

In the multifunctional material shown in FIG. 12 , a photocatalyst layer 2 is formed on the surface of the substrate 1 with a binder layer 6 interposed therebetween, and the photocatalyst particles 3 constituting the photocatalyst layer 2 are combined with mutual potential energy Also, on the surface of the photocatalyst particles 3, Ag, Cu, Cu₂Electron trapping particles 5 such as O are immobilized.

In the multifunctional material shown in FIG. 13, a photocatalyst layer 2 is formed on the surface of the substrate 1 with a binder layer 6 interposed therebetween, and the photocatalyst particles 3 constituting the photocatalyst layer 2 are combined by solid-state sintering, , Ag, Cu, Cu on the surface of the photocatalyst particle 3₂Electron trapping particles 5 such as O are immobilized.

In the multifunctional material shown in FIG. 14, the photocatalyst layer 2 is installed on the substrate 1 through the binder layer 6, and in the gap formed between the photocatalyst particles 3 constituting the photocatalyst layer 2, the Particles 4 smaller than the gap are filled, and the photocatalyst particles 3 are bonded to each other through the small particles 4, and Ag or Pt or metal particles 5 are immobilized on the surface of the photocatalyst particles 3 has been

In the above description, the substrate 1 may be any of ceramics such as tiles, sanitary ware, glass, resin, metal, wood, or a composite thereof.

In addition, the photocatalytic particle 3 is a semiconductor particle having a band cap sufficient to exhibit a photocatalytic function such as an antibacterial function, a deodorizing function, and the like. There is a theory that the photocatalyst particles are electrocuted when a voltage higher than a predetermined voltage is applied as the reason why the photocatalyst particles have antibacterial properties. In order to generate active oxygen, when one of the conduction bands of the semiconductor is represented by a band model, it is required that the upper end of the hydrogen generation potential is above the hydrogen generation potential and the upper end of the valence band is below the oxygen generation potential. . For semiconductors that satisfy this condition, TiO₂, SrTiO₃, ZnO, SiC, potassium phosphide, CdS, CdSe, MoS₃ etc. In addition, since the position of the conduction band moves upward when atomized, if the layer can be composed of fine particles of about 1 to 10 nm, SnO₂, WO₃, Fe₂O₃, Bi₂O₃ There is also the possibility of generating reactive oxygen species. Among these, anatase-type TiO is chemically stable, cheap and high activity fine particles can be obtained.₂is particularly preferred.

In addition, electron trapping particles refer to those that capture electrons when electrons and holes irradiated with light are irradiated to an electric photocatalyst and prevent recombination between electrons and holes. Specifically, Ag, Cu, Pt, Pd , Ni, Co, Fe, Cu₂O etc. are mentioned.

Further, the electrical binder layer 6 is made of, for example, a thermoplastic material such as glaze, inorganic glass, thermoplastic resin, and solder. In this way, by forming the binder layer with a thermoplastic material, the photocatalyst can be applied on the binder layer by a simple and inexpensive method such as spray coating at room temperature, and furthermore, the substrate 1, the binder layer 6 and The photocatalyst layer 2 can be firmly bonded, which is advantageous in terms of manufacturing cost.

In addition, the multifunctional material having a photocatalytic function according to the present invention is constituted by laminating a photocatalyst layer made of photocatalyst particles on a sheet-like binder layer made of a thermoplastic material or embedding a part thereof. Functions such as deodorization, antifouling, antibacterial, and antifungal properties can be added to existing tiles by heating such a sheet-like multifunctional material for use on existing tiles, sanitary ware, and building materials.

The average particle diameter of the photocatalyst particles 3 constituting the photocatalyst layer 2 is preferably less than 0.3 μm in order to increase the photocatalytic activity by increasing the specific surface area.

The average particle diameter of the photocatalyst particles 3 constituting the photocatalyst layer 2 is preferably less than 0.3 μm in order to increase the photocatalytic activity by increasing the specific surface area.

The thickness of the photocatalyst layer 2 is preferably 0.1 μm to 0.9 μm. If the thickness is less than 0.1 µm, the photocatalyst particles are locally buried in the binder layer 6, and there is a portion on the surface of the multifunctional material that cannot exhibit catalytic activity. In addition, when it exceeds 0.9 μm, the non-uniformity of the thickness becomes large, and when the contamination adheres to the sample, the contamination becomes difficult to fall off. Here, the thickness of the photocatalyst layer includes the portion from the outermost surface of the photocatalyst thin film to the portion buried in the lower layer of the gray, specifically, elemental analysis such as EBMA (electron beam microanalyzer), etc., to construct the gray layer It is measured by finding the distance from the top to the outermost surface of the part where the value of the main component element increases and becomes almost constant.

In addition, a design effect is also obtained by changing the thickness of the photocatalyst layer 2 . That is, if the thickness is 0.2 μm or more and less than 0.4 μm, the iris color pattern can be attached by the interference action of light on the thick part of the photocatalyst layer film, and when the background color, shape, or a combination thereof is used in appearance, the interference action of the light The thickness of the photocatalyst layer film may be manufactured to be 0.1 µm or more and less than 0.2 µm, or 0.4 µm or more and less than 1 µm, excluding the portion where This method can be applied to a wide range of tiles, washbasins, bathtubs, toilets, sinks, countertops, and the like.

In the case of mutual bonding with only the photocatalyst particles 3, there is no choice but to rely on the potential energy (adsorption) or sintering between the photocatalyst particles. However, in the case of using the mutual sintering action of the photocatalyst particles, sintering must be carried out at a very high temperature. On the other hand, in the case of adsorption, if the specific surface area of the photocatalyst particles is significantly increased and the packing property is not good, the bonding property is not sufficient, and the photocatalyst The method is not limited in order to produce a multifunctional material having sufficient catalytic activity and wear resistance, such as consuming only the active point adsorption of particles.

In addition, if a particle larger than the gap between the photocatalyst particles 3 is used to strengthen the bonding of the photocatalyst particles 3, sufficient bonding strength cannot be obtained, and the photocatalyst particles exposed on the surface of the multifunctional material are partially covered. On the surface of the multifunctional material, there is a portion where catalytic activity cannot be exhibited, and the antibacterial property is remarkably deteriorated because bacteria reside in that portion.

Incidentally, the gap between the photocatalyst particles as used herein refers to both the neck portion between the photocatalyst particles 3 and 3 shown in Fig. 16A and the pores between the photocatalyst particles 3 and 3 as shown in Fig. 16B. . Therefore, the particle diameter smaller than the gap between the photocatalyst particles as used herein refers to a particle smaller than the gap between the neck portion between the photocatalyst particles and the pores between the photocatalyst particles. As a means for bonding the photocatalyst particles to each other, it is a particularly effective means in the case of FIG. 16(b).

The small particles 4 filled in the gaps of the photocatalyst particles 3 are basically not limited by materials, but those having excellent adsorption power are preferable. In materials with extremely weak adsorption capacity, the photocatalyst particles bind to each other and the objective cannot be achieved. In addition, in materials with extremely strong adsorption power, the probability of covering the active points on the surface of the photocatalyst particles is greater than being inserted into the gap. From this point of view, preferred materials for the particles filled in the gaps between the photocatalyst particles are metals such as Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni, or their oxides, and conventionally, adsorption carriers The zeolite, activated carbon, clay, etc. used as the material is not preferable. Among the above metal oxides, tin oxide is preferable in terms of having an appropriate adsorption capacity, and metals or oxides such as Ag and Cu have antibacterial and deodorizing properties in addition to binding photocatalyst particles to each other. In particular, it is preferable in that it has a function of assisting photocatalysis when there is no light irradiation. That is, the metal particles 5 may be used as the small particles 4 filled in the gaps between the photocatalytic particles 3 .

In addition, it is preferable that the average particle diameter of the particles (4) filled in the gaps of the photocatalyst particles (3) is 4/5 or less of the average particle diameter of the photocatalyst particles (3).

Particles 4 filling the gaps between the photocatalyst particles 3 adhere to some extent on the photocatalyst particles as well as the gaps between the photocatalyst particles in the current manufacturing method. Thus, when the particle diameter of the particles filling the gap exceeds 4/5 of the average particle diameter of the photocatalyst particles, the probability of adhering to the surface of the photocatalyst particles is higher than the gap between the photocatalyst particles, and the bonding strength between the photocatalyst particles 3 decreases. In addition, if the particles that fill the gap are larger than the photocatalyst particles, the photocatalytic particles are partially covered, and there is a part on the surface of the multifunctional material where catalytic activity cannot be exhibited. .

In addition, it is preferable that the average particle diameter of the particles 4 filled in the gaps between the photocatalyst particles 3 is less than 0.01 μm to increase the specific surface area and obtain a suitable adsorption force.

In addition, the amount of the particles (4) filled in the gaps of the photocatalyst particles (3) with respect to the total amount of the photocatalyst particles (3) and the charged particles (4) is preferably 10% or more and 60% or less in molar ratio. In the case of fixing the photocatalyst layer by interposing a binder on the substrate by heat treatment in a temperature range where sintering does not occur between the photocatalyst particles, if the amount of particles filling the gap is too small, the photocatalyst particles do not bond strongly, while filling the gap. If the amount of particles is too large, the amount of particles covering the photocatalyst particles becomes large, so that there is a part on the surface of the multifunctional material that cannot exhibit catalytic activity and bacteria can reside in that part. do.

In addition, as a material constituting the particles 4 filled in the gaps of the photocatalytic particles 3, a material whose vapor pressure is higher than that of the material constituting the photocatalytic particles is selected, and the particles filled in the gaps of the photocatalytic particles are added to the photocatalyst particles. It is preferable to aggregate it in the neck part in between. This is because it is better not only to be filled but also to be sintered in order to obtain stronger bonding between the photocatalyst particles and to increase the peel strength of the photocatalyst layer. In addition, if a material having such a high vapor pressure is selected for the particles 4 that fill the gap, it may function as a sintering aid and reduce the sintering temperature.

Examples of substances having such a high vapor pressure include tin oxide, bismuth oxide, zinc oxide, and the like, but tin oxide is preferable in terms of stability.

In addition, the thickness of the layer containing the particles (4) filled in the gaps between the photocatalyst particles (3) is preferably 0.1 μm or more. If the thickness of this layer is less than 0.1 μm, there is a part where photocatalytic particles (particles that fill the gaps by this manufacturing method) cannot exhibit catalytic activity on the surface of the multifunctional material locally filled in the binder layer 6, and the Since bacteria can remain in the part, in particular, the antibacterial property is remarkably deteriorated. Here, the thickness of the layer containing the particles filled in the gaps of the photocatalyst particles is the thickness from the outermost surface to the portion where the lower layer of the binder is filled, and each unevenness is made uniform.

15 is a view for explaining an example of a method for manufacturing a multifunctional material having a photocatalytic function according to the present invention. In the present invention, first, the substrate 1 is prepared as shown in FIG. As shown, a binder layer 6 is formed on the surface of the substrate 1 . As the binder layer 6, a material whose softening temperature is lower than the softening temperature of the substrate 1 is selected. For example, in the case of a tile, an enamel material, or ceramics, a glaze layer or a printing layer can be used as the binder layer 6 as it is.

Then, as shown in Fig. 15 (c), TiO on the binder layer 6₂ A photocatalyst layer 2 made of photocatalyst particles such as particles is formed. At this time, the photocatalyst layer 2 may have a bonding strength of a degree not to be separated from the binder layer 6 at the time of subsequent firing, and may be placed on the binder layer 6 .

Alternatively, before forming the binder layer 6 on the surface of the substrate 1, as shown in FIG. 15(b'), a photocatalyst layer 2 is formed on the binder layer 6 and placed, and this binder layer 6 ) may be arranged on the substrate 1 .

Then, the softening temperature of the binder layer 6 is higher than 20° C. and less than 320° C., and is heat-treated at an ambient temperature lower than the softening temperature of the substrate 1, as shown in FIG. 15D or FIGS. 9 to 14. As shown, the lower layer of the photocatalyst layer 2 on the side of the binder layer is almost partially settled in the molten binder layer and the binder layer solidifies, so that the part is filled in the binder layer and is firmly maintained. In addition, as shown in FIG. 16a, the photocatalyst particles 3 constituting the surface layer in contact with the outside air of the photocatalyst layer 2 are partially bonded as shown in FIG. 16A by mutual potential energy, intermolecular force, or sintering by firing, and another part is separated as shown in Fig. 16b. That is, the surface of the photocatalyst particles is substantially exposed to the outside in the surface layer.

Here, if the heat treatment temperature is set higher than the softening temperature of the binder layer 6 in the range of 20° C. and less than 320° C., if it is less than 20° C., the softening of the binder layer takes time, and the retention of the photocatalyst particles 3a is difficult. On the other hand, if it exceeds 320°C, the photocatalyst particles are buried into the binder layer of the photocatalyst particles due to rapid melting of the binder layer, or an exposed surface is generated, and further cuts or pinholes occur.

In addition, when the specific gravity of the photocatalyst particles 3 is δt and the specific gravity of the binder layer 6 is δb, 0 δt-δb 3.0, preferably 0.5 δt-δb 0.2. This means that when the specific gravity difference between the photocatalyst particles and the binder layer is very small, when the binder layer is melted, the movement speed of the photocatalyst particles in the vertical direction in the binder layer is delayed, and the photocatalyst particles are easily peeled off after firing, and the photocatalyst If the specific gravity difference between the particles and the binder layer is too large, the vertical movement speed of the photocatalyst particles increases, and the photocatalyst particles are almost filled in the binder layer. Because.

As an application method of this method, even when ?t-?b&gt;3.0 must be set, a second binder layer having 0?t-?b?3.0 may be interposed between the binder layer and the photocatalyst particles.

Further, when ?t-2b&lt;0, pressing during heat treatment has the same effect as increasing the specific gravity difference ?t-?b. Therefore, the same effect as when 0δt-δb3.0 is obtained by the HIP treatment and the hot press treatment.

In addition, the gap between the photocatalyst particles constituting the portion exposed from the binder layer 6, specifically, the neck portion of the photocatalyst particle 3b shown in FIG. 16A or the photocatalyst particle 3 shown in FIG. Small particle diameter particles 4 (metals or oxides such as Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni, etc.) may be filled to bind the photocatalyst particles together.

Further, as another method of manufacturing a multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material is formed on a substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is A photocatalyst layer (2) is formed by applying a mixture of photocatalyst particles (3) and small particle diameter particles (4) in a sol or precursor state on the clothes, and then the electric binder layer (6) is softened to form a photocatalyst A part of the lower layer of the layer 2 may be buried in the binder layer 6 and then solidified.

According to this method, it is convenient and at the same time, the photocatalyst layer is formed by applying a mixture of the particles 4 and the photocatalyst particles 3, which have filled the gaps in advance, in a sol or precursor state, thereby filling the gaps with the photocatalyst particles 3 It is convenient to control the mixing ratio of the particles (4).

Further, as another method for producing a multifunctional material having a photocatalytic function according to the present invention, a photocatalyst layer 2 made of photocatalyst particles 3 is formed on a sheet-like binder layer 6 made of a thermoplastic material, and then the photocatalyst The sheet-like binder layer on which the layer is formed is placed on or adhered to the substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is softened to remove a part of the lower layer of the photocatalyst layer 2 It is buried in the binder layer 6, then the binder layer is solidified, and a solution containing the metal particles 4 is applied to the photocatalyst layer again, and the small particle diameter is fixed to the photocatalyst particles 3 by heat treatment. also good

Further, as another method of manufacturing a multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material is formed on a substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is A photocatalyst layer 2 made of photocatalyst particles 3 is formed on the garment, and then the binder layer 6 is softened to partially bury the lower layer of the photocatalyst layer 2 in the binder layer 6, and then After the binder layer is solidified, a solution containing particles having a small electrical particle size is applied to the photocatalyst layer again, and heat treatment is performed to fix the particles 4 having a small electrical particle size to the photocatalyst particles 3 .

This method is a method that can be carried out relatively easily when the particles filling the gap are oxides, and furthermore, when a relatively porous photocatalyst layer is prepared, a large amount of particles filling the gap can be deposited.

Further, as another method for producing a multifunctional material having a photocatalytic function according to the present invention, a photocatalyst layer 2 composed of photocatalyst particles 3 is formed on a sheet-like binder layer 6 made of a thermoplastic material, and then this photocatalyst layer The sheet-like binder layer on which the was formed is placed or adhered on the substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is softened to form a part of the lower layer of the photocatalyst layer 2 as a binder layer ( 6), then the binder layer is solidified, the solution containing the metal particles 4 is applied to the photocatalyst layer again, and the particles 4 having a small electric particle diameter are fixed to the photocatalyst particles 3 by heat treatment. also good

Further, as another method of manufacturing a multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material is formed on a substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is A photocatalyst layer 2 made of photocatalyst particles 3 is formed on the garment, and then the binder layer is softened to bury a part of the lower layer of the photocatalyst layer in the binder layer, then the binder layer is solidified, and the photocatalyst layer is again A solution containing the ions of the small metal particles (4) may be applied to the surface, and then, the metal ions may be reduced by irradiating light containing ultraviolet rays so as to be immobilized on the photocatalyst particles (3).

This method is a method that can be carried out relatively easily when the particles filling the gap are metal, and can fix the metal for a very short time (minutes). Moreover, any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, etc. may be sufficient as the lamp|ramp used for ultraviolet irradiation.

Further, as another method of manufacturing a multifunctional material having a photocatalytic function according to the present invention, a photocatalyst layer made of photocatalyst particles is formed on a sheet-like binder layer made of a thermoplastic material, and then a sheet-like binder layer (6) on which the photocatalyst layer is formed. is placed or adhered to the substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is softened to bury a part of the lower layer of the photocatalyst layer in the binder layer 6, and then the binder layer ( 6) is solidified, and a solution containing the ions of the metal particles 4 having a small particle diameter is applied to the photocatalyst layer 2 again, and then the metal ions are reduced by irradiating light containing ultraviolet rays to form the photocatalyst particles. It may be made to be fixed.

Further, as another method of manufacturing a multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material is formed on a substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is A photocatalyst layer 2 of photocatalyst particles 3 is formed on the photocatalyst layer 2, a solution containing ions of the metal particles 4 having a small particle diameter is applied to the photocatalyst layer 2, and then light containing ultraviolet light It may be irradiated to reduce metal ions to fix them on the photocatalyst particles 3, soften the binder layer 6 again, so that a part of the lower layer of the photocatalyst layer is buried in the binder layer, and then the binder layer is solidified. .

According to this method, since the heat treatment process can be completed once, productivity is improved.

Further, as another method for manufacturing a multifunctional material having a photocatalytic function according to the present invention, a photocatalyst layer 2 made of photocatalyst particles 3 is formed on a sheet-like binder layer 6 made of a thermoplastic material, and the photocatalyst layer (2) is coated with a solution containing the ions of the metal particles (4) with a small particle diameter, and then the metal ions are reduced by irradiating light containing ultraviolet rays to fix the metal ions on the photocatalyst particles (3), and again the photocatalyst layer ( The sheet-like binder layer on which 2) has been formed is placed and adhered on a substrate 1 such as ceramic, resin or metal, and then the binder layer 6 is softened to remove a part of the lower layer of the photocatalyst layer 2 You may make it bury in a binder layer, and then make it solidify the binder layer.

Here, the photocatalyst particles are ZnO, and the metal particles 4 filled in the gaps between the photocatalyst particles are Ag or Ag.₂It is possible to make it O. Ag or Ag₂O particles not only strengthen the bond between ZnO particles, which are photocatalysts, but also enhance the photocatalytic effect of ZnO, and also have antibacterial and deodorizing effects on their own. In addition, by selecting ZnO as a photocatalyst, it is possible to eliminate the coloring caused by Ag ions, and to improve the design effect by the color pattern of the base material or their combination.

In addition, the photocatalyst layer is contacted with a solution containing a salt that is insoluble with ions of a metal charged in the gap between the electrophotocatalyst particles and forms a colorless or white salt, and then is irradiated with light containing ultraviolet rays. may do

By doing this, ZnO and Ag or Ag₂Even without the combination of O, it is possible to solve the coloration caused by the particles filling the gap, and it is possible to improve the design effect by the color and shape of the base material or their combination.

In addition, the photocatalyst particles (3) are TiO₂and the heat treatment temperature for softening the binder layer 6 may be 800°C or higher and 1000°C or lower. Above 800°C, TiO₂ Since a neck part is generated by initial sintering between particles, TiO₂ The bonding strength between particles is improved, but when it exceeds 1000°C, it shifts to the medium-term sintering process, and TiO₂Since the volume shrinkage of the photocatalyst layer accompanying solid-phase sintering of

In addition, the photocatalytic particles are TiO₂A solution containing a salt that is insoluble with Ag ions and forms a colorless or white salt is used as the particle 4 filled in the gap between the photocatalyst particles as KI, KCl, FeCl₃ It is good also as an aqueous halide solution, such as Ag is insoluble, colorless, insoluble, such as AgI and AgCl, and forms a colorless or white salt between it and an alkali halide, so that it is possible to improve the design of the base material by the background color, shape, or combination thereof.

In addition, when a dispersing step is provided as a pre-step of the step of applying the photocatalyst particles on the binder layer, the dispersing agent for dispersing the sol or precursor that becomes the photocatalyst particles in the solution in this dispersing step is higher than the heat treatment temperature for softening the binder layer. It is preferable to use only a component that vaporizes at a low temperature.

In the prior art, TiO in the dispersion process had no deodorization at less than 320 ° C.₂ Since the dispersant adhering to the surface of the particle remains without sufficient vaporization and evaporation, TiO₂This is because the particle surface is not sufficiently exposed to the outermost surface of the substrate, and the photocatalytic function becomes insufficient. Moreover, as a dispersing agent which vaporizes at low temperature, the organic dispersing agent of molecular weight 10,000 or less, and a phosphoric acid type dispersing agent are preferable.

Specific examples are given below.

(Example 1)

SiO on the surface of a porcelain tile substrate with a length of 150 mm on each side₂-Al₂O₃-Na/K₂A binder layer made of O frit is formed by spray coating, and after drying, 15% TiO₂ An aqueous sol solution is applied by spray coating, and TiO having a film thickness of 0.8 µm₂A layer is formed, followed by a binder layer and TiO₂The substrate on which the layers were laminated was heated and fired using a roller-hearth kiln at different ambient temperatures for each example, followed by cooling to obtain a multifunctional material.

Here, TiO₂ The sol aqueous solution means, for example, a crystal grain size of about 0.007 to 0.2 μm and anatase-type TiO obtained by gas decomposing TiCl under hydrothermal conditions in the range of 100 to 200° C. in an autoclave.₂is dispersed in a sol state by several % to several tens% in an acidic aqueous solution such as nitric acid or hydrochloric acid or a basic aqueous solution such as ammonia, and organic acid salts of triethanolamine and trimethylolamine, pentaerythritol , triethylolpropane, etc. are added in the range of 0.5% or less. Also TiO₂ The particle size of the sol was calculated by SEM observation image processing, and the crystal grain size was calculated by powder X-ray diffraction from the integral width.

In addition, although the distribution method was performed by the spray coating method, it is expected that the same results will be obtained also with the dip coating method and the spin coating method.

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

For the antibacterial properties, the sterilization effect against Escherichia coli (S. Escherichia coli W3110) was tested. 0.15 ml of bacterial solution (1-5 × 10) on the outermost surface of multifunctional material sterilized with 70% ethanol⁴CFU) was added dropwise, placed on a glass plate (10 x 10 cm), and adhered to the outermost surface of the substrate to obtain a sample. After irradiating with a white light (3500 lux) for 30 minutes, the bacterial solution of the irradiated sample and the sample maintained under light-shielding conditions was wiped with sterile gauze, recovered with 10 ml of physiological saline, and the survival rate of the bacteria was obtained as an evaluation index.

The abrasion resistance was evaluated by performing perturbation abrasion using a plastic eraser, and comparing the change in appearance.

Porcelain tile as a substrate in (Table 1) below, SiO as a binder₂-Al₂O₃-Na/K₂When O frit was used, it showed the change of antibacterial and abrasion resistance according to the change of firing temperature.

[Table 1]

Substrate = ceramic tile, binder = SiO₂-Al₂O₃-Na/K₂O frit

Photocatalyst = TiO₂

<img file="KR100357482B1_D0001.tif" />

+++ : Survival rate of E. coli less than 10%

++ : Survival rate of E. coli 10% or more but less than 30%

+ : Survival rate of E. coli 30% or more but less than 70%

- : Survival of Escherichia coli by more than 70%

: No change for 40 round trips

: A scratch occurs in 10 to 40 perturbations, and the photocatalyst layer (TiO₂layer) is peeled

: A scratch occurs in 5 to 10 perturbations, and the photocatalyst layer (TiO₂layer) is peeled

×: A scratch occurs in perturbation of 5 times or less, and the photocatalyst layer (TiO₂layer) is peeled

SiO-Al used here as a binder₂O₃-Na/K₂The specific gravity of the O front is 2.4, and the film thickness when applied is 200 μm. The softening temperature was 680 °C. In addition, TiO obtained in (Table 1)₂is anatase type in Nos. 1 to 3, specific gravity is 3.9, No. About 4 and 5, it was a rutile type, and specific gravity was 4.2.

In (Table 1), No. 1 is anatase-type TiO constituting the lowermost layer of the photocatalyst layer because the firing temperature is only 20°C higher than the softening temperature of the binder and the viscosity of the binder is not sufficiently low.₂ The particles were not sufficiently embedded in the binder layer, and therefore, in the abrasion resistance test, scratches occurred and peeled off after 5 to 10 perturbations. In addition, with respect to antibacterial properties, it is an anatase type having excellent photocatalytic activity, and TiO at 300°C or higher₂ In the TG-DTA observation of the sol, the glass upper part is almost decomposed and vaporized, and TiO₂ Dispersants such as surface treatment agents adhering to the surface are interpreted as vaporized, but at a firing temperature of 700° C. and a treatment temperature slightly higher than that, an excellent value of ++ was obtained.

No. 3 to 5 were cases where the firing temperature was 800°C or higher and 1000°C or lower, but in all cases, durability did not change even in 40 or more perturbation tests, and was extremely excellent. The cause is the surface TiO₂ It is thought that the neck part was produced|generated with the initial firing of particle|grains. In the case of treatment at 1100°C, after cooling and solidification, TiO is applied to the surface of the multifunctional material taken out from the roller hearth kiln.₂There is a crack in the floor. This is TiO₂ Judging from the TMA measurement of the test piece, TiO₂ It is thought to be due to medium-term sintering accompanied by significant volumetric shrinkage of the particles.

No. In 4 and 5, the antibacterial properties were all bad. It is thought that there are two causes for this. One is TiO₂ The particles are in a rutile-type phase transition, and the other is that the firing temperature is higher than the softening temperature of the binder by 300°C, the viscosity of the binder is too low, and TiO constituting the photocatalyst layer₂ It is considered that the particle|grains have buried in the binder layer. where TiO₂ It cannot be considered that the cause is only that the particle has a phase transition to the rutile type. Rutile TiO₂also in anatase-type TiO₂The reason why it deteriorated is because it has some photocatalytic activity. For example, TiO directly on a porous anatase substrate₂ After spray coating the sol and firing at 950°C, the antibacterial property of the material solidified by cooling was +. Therefore, the sintering temperature is higher than the softening temperature of the binder by more than 300°C, and the viscosity of the binder is too low for TiO constituting the photocatalyst layer.₂ The fact that the particles are buried in the binder layer is also interpreted as one of the causes.

In addition, a mixed layer of Ti and Si was observed by elemental analysis of Ti and Si (main component of the binder) by EBMA or the like in the cross-sectional direction of the material, and TiO, which is a photocatalytic particle₂was confirmed to be buried.

Example 1 above, that is, at least the photocatalyst is TiO₂, the binder layer is SiO₂-Al₂O-Na/K₂In the case of O frit, the following were confirmed.

When the sintering temperature is higher than the softening temperature of the binder by more than 20°C and the multifunctional material is manufactured under the condition that does not exceed 300°C, it is possible to produce a multifunctional material with good antibacterial and abrasion resistance. The cause is that the viscosity of the binder in the above temperature range is TiO₂It is thought that this is because is adjusted to a value that can be properly embedded in the binder layer.

The multifunctional material produced in is TiO₂ Burial of the particles into the binder layer was confirmed.

When the firing temperature was 800°C or higher and 1000°C or lower, the abrasion resistance did not change even in 40 or more perturbation tests, and was extremely excellent. TiO₂ It is thought that it is due to the strong bond accompanying the formation of the neck part between particles.

(Example 2)

SiO on the surface of 100×100×5 mm alumina substrate (alumina purity 96%)₂-Al₂O₃-After forming a binder layer made of PbO frit by spray coating and drying, 15% TiO₂ An aqueous sol solution (same as in Example 1) was applied by spray coating, and TiO having a film thickness of 0.8 µm₂A layer is formed, followed by a binder layer and TiO₂The substrate on which the layers were laminated was heated and fired using a roller Haas Kilun at different atmospheric temperatures for each Example, and then cooled to obtain a multifunctional material.

Alumina as a base material in the following (Table 2), SiO of the binder₂-Al₂O₃-Shows the change in antibacterial and abrasion resistance according to the change in firing temperature when PbO frit is used.

[Table 2]

Substrate = alumina plate 100 × 100 × 5 mm, binder = SiO₂-Al₂O₃-PbO frit,

Photocatalyst = TiO₂

<img file="KR100357482B1_D0002.tif" />

Here, SiO used as a binder₂-Al₂O₃The softening temperature of the -PbO frit was 540°C, the specific gravity was 3.8, and the film thickness when applied was 150 µm. Also obtained TiO₂All of the crystalline forms were anatase form.

In the abrasion resistance test of (Table 2), No. No. 6 was scratched and peeled off at 10 or less perturbations, but No. No. 7 and 8 showed no flaws even after 10 or more perturbations, and No. In 9 and 10, good results were obtained that did not cause scratches even with more than 40 perturbations.

No. The reason that there was no flaw even with perturbations from 9, 10 to 40 times or more was because the firing temperature was 800°C or higher, so TiO₂ A neck is created in between, and TiO₂ It is thought that this is because the particles are strongly bonded to each other.

No. In 6, since the sintering temperature was only 20°C higher than the softening temperature of the binder and the viscosity of the binder was not sufficiently low, the anatase-type TiO constituting the lowermost layer of the photocatalyst layer was scratched and peeled by perturbation more than 10 times.₂ It is considered that it is because the particle|grains were not fully embedded in the binder layer.

No. In the case of 7 and 8, the difference between the firing temperature and the softening temperature of the binder of the one that did not reach the temperature at which the neck part was formed was not damaged even after 10 or more perturbations.₂It is thought that this is because is adjusted to a value that can be properly embedded in the binder layer.

On the other hand, in the antimicrobial test of (Table 2), No. 6 to 9 showed a good result as +++ or ++, but No and 10 became +. This is because the sintering temperature is 320°C higher than the softening temperature of the binder and the viscosity of the binder is too low, so TiO constituting the photocatalyst layer₂It is thought that this is because the particle|grains have been embedded in the binder layer.

(Example 3)

SiO₂-Al₂O₂-After cooling and solidifying the BaO frit when melting in the room, a 100×100×1 mm glass sheet was prepared, and 15% TiO₂ A sol aqueous solution (same as Example 1) was applied by spray coating, and TiO having a film thickness of 0.8 μm₂layer was formed. Then, the glass sheet was placed on an alumina substrate (100×100×5 mm), and after heating and firing in a siliconite furnace at different ambient temperatures for each example, cooling and solidification was performed to obtain a multifunctional material.

Table 3 below shows the change in antibacterial and abrasion resistance according to the change in the firing temperature of the multifunctional material.

[Table 3]

Base = alumina plate ((100 × 100 × 5 mmi, binder = SiO)₂-Al₂O₃-BaO sheet

Photocatalyst = TiO₂

<img file="KR100357482B1_D0003.tif" />

SiO used here as a binder₂-Al₂O₃-BaO frit softening temperature is 620°C, specific gravity is 2.8, TiO as a multifunctional material₂The crystalline form of No. 11 to 13 are anatase type, No. 14 was rutile.

In the abrasion resistance test of (Table 3), No. No. 11 was scratched and peeled off with less than 10 perturbations, but No. 12 shows no damage even with 10 or more perturbations, and No. 13 and 14, good results were obtained with no flaws even with more than 40 perturbations.

No. 13, 14, TiO was not damaged even with more than 40 perturbations because the firing temperature was 800°C or higher.₂ A neck is created between the particles, and TiO₂ It is thought that it is because the particle|grains were strongly couple|bonded with each other.

No. Anatase-type TiO constituting the lowermost layer of the photocatalyst layer because the sintering temperature was only 20° C. higher than the softening temperature of the binder and the viscosity of the binder was not sufficiently low when the perturbation occurred 11 to 10 times or more.₂ It is considered that it is because the particle|grains were not fully embedded in the binder layer.

No. The difference between the sintering temperature that did not reach the temperature at which the neck part was formed and the softening temperature of the binder showed that the viscosity of the binder was determined by TiO₂It is thought that this is because it has been adjusted to a value that can be properly embedded in a binder layer or the like.

On the other hand, in the antimicrobial test of (Table 3), No. In 11 to 13, good results were obtained with +++ or ++, but No. 14 became -. This is TiO₂TiO constituting the photocatalyst layer because of the rutile type, the firing temperature being 320°C higher than the softening temperature of the binder, and the viscosity of the binder being too low₂ It is thought that it is due to two causes in which the particle|grains have been buried in the binder layer.

From the above, the binder in advance of TiO₂ In the method of obtaining a multifunctional material by attaching particles to a substrate after application, and firing to obtain a multifunctional material, a binder is applied to the surface of the substrate, and then TiO₂ It was confirmed that the same effect as the method of obtaining a multifunctional material by applying the particles was obtained.

(Example 4)

After applying an acrylic resin binder to the surface of a 100×100×5 mm polyimide-based resin substrate, 15% TiO₂ An aqueous sol solution is applied by spray coating, and TiO having a film thickness of 0.8 µm₂A layer is formed, followed by a binder layer and TiO₂The layered layers were fired at 150° C. in a nichrome furnace to obtain a multifunctional material. Table 4 below shows the change in antibacterial and abrasion resistance according to the change in the firing temperature of the multifunctional material.

[Table 4]

Base = polyimide resin, binder = acrylic resin,

Photocatalyst = TiO₂, firing temperature = 150°C

<img file="KR100357482B1_D0004.tif" />

In addition, in (Table 4), 15% TiO₂ The method for adjusting the aqueous sol solution was changed as follows.

No. 15: 15% TiO of the use of Example 1₂ The sol aqueous solution was used as it was.

No. 16: After hydrolyzing an aqueous TiCl solution at 110°C to 150°C in an autoclave, the product was adjusted to pH 0.8 with nitric acid to disperse without using a surface modifier, followed by removal of aggregates. In this case, spray coating was performed immediately after the agglomerate was removed.

Here, TiO₂has a specific gravity of 3.9, crystalline form is anatase, acrylic resin has a specific gravity of 0.9, and the temperature at which viscosity corresponds to the glass softening point is 70°C.

Regarding wear resistance, No. In any of the conditions of 15 and 16, there were no scratches even after more than 10 perturbations. This means that the range of the difference between the firing temperature and the softening temperature of the binder determines the viscosity of the binder in TiO.₂I think this is because it has become a value that can be adjusted to a value that can be properly embedded in the binder layer.

On the other hand, regarding the antibacterial test, No. 15 became -, but No. 16 obtained good results with ++, and it was found that a multifunctional material having antibacterial properties can be produced even at less than 30°C. This difference is No. 1 in DTA-TC. 15 TiO₂ In the sol, there are components that decompose and evaporate at 200-350°C, but No. 16 was not recognized, so TiO₂It is thought to be caused by the presence or absence of organic components with

In addition, here, the specific gravity difference between anatase and acrylic resin was 3, but the difference was that the TiO constituting the photocatalyst layer was₂ It was confirmed that the particles were not embedded in the binder layer and had good antibacterial properties.

(Example 5)

After forming a binder layer made of frits with different specific gravity on the surface of an alumina substrate of 100 × 100 × 5 mm by spray coating method, and drying, 15% TiO₂ The sol aqueous solution was spray coated with TiO having a thickness of 0.8 μm.₂forming a layer, followed by a binder layer and TiO₂The laminated substrate was heated and fired at an atmospheric temperature of 750° C. using a roller Haas Kilun, and then cooled and solidified to obtain a multifunctional material.

Table 5 below shows the change in antibacterial and abrasion resistance according to the change in the firing temperature of the multifunctional material.

[Table 5]

Substrate = alumina plate (10 × 100 × 5 mm), photocatalyst = TiO₂

<img file="KR100357482B1_D0005.tif" />

Regarding the antibacterial test, No. None of 17-20 gave good results of +++. In any case, the firing temperature is higher than the softening temperature of the binder in the range of 30°C to 300°C, and the range of the difference between the firing temperature and the softening temperature of the binder is the viscosity of the binder.₂ It is thought that this is because it was a value adjusted to a value that can be properly embedded in the binder layer.

Regarding wear resistance, No. No. 17 was scratched and peeled off at 15 or less perturbations, but No. 18-20 showed no flaws even after more than 10 perturbations.

As a cause, No. In 17, unlike the others, the specific gravity of the binder is TiO₂Since it is larger than the specific gravity of the anatase-type TiO constituting the lowermost layer of the photocatalyst layer₂It is considered that it is because the particle|grains were not fully embedded in the binder layer.

Therefore, the wear resistance of multifunctional materials is₂The specific gravity of the binder and the binder also influences, and the specific gravity of the binder is TiO₂It was found that if the specific gravity was larger than the specific gravity, it deteriorated.

(Example 6)

SiO on the surface of a ceramic tile base of 150 mm on each side₂-Al₂O₃A binder layer with a -BaO front (softening temperature of 620°C) is formed, and TiO₂Sol and SiO₂After mixing and stirring the sol, the aqueous solution was applied by spray coating, calcined at 750° C., and solidified by cooling to obtain a multifunctional material.

Also, TiO₂ The concentration of the sol is 4-6 wt% NH₃Adjusted to pH 11 with aqueous solution, TiO₂ The grain size of the particles is 0.01μm, and SiO₂The grain size of the particles is 0.0035 μm.

For the multifunctional material constructed in this way, TiO₂with SiO₂SiO for the total amount of₂The results of the antibacterial test and the abrasion resistance test when the amount (molar ratio) was variously changed are shown below (Table 6).

[Table 6]

Substrate = ceramic tile, binder = SiO₂-Al₂O₃-BaO frits,

Photocatalyst = TiO₂, interstitial particles = SiO₂Sol (0.0035μm)

<img file="KR100357482B1_D0006.tif" />

SnO for wear resistance test₂It improved with the increase of the amount, and there was no scratch or change even after 40 perturbation tests by adding 10% or more.

For the antibacterial test, when the range is up to 20% or more, it is +++ as in the case of no addition, and when it reaches 60%, it stays as ++. When more is added, TiO on the surface of the substrate₂ The probability of covering the particles increased, and the antibacterial properties deteriorated, and at 100% it became -.

Therefore, SnO₂TiO in the molar ratio₂with SnO₂10% or more and 60% or less of the total amount, preferably 10% or more and 20% or less, can provide a multifunctional material excellent in antibacterial and abrasion resistance.

where the wear resistance is SnO₂The improvement as the amount of is increased is by the mechanism shown below. That is, SnO₂is TiO₂Since the vapor pressure is higher at a high temperature of 600°C or higher than that of the particles, TiO before sintering₂The particle (3b) gap is L as shown in Fig. 17a.₀Ina, TiO₂On the surface with positive curvature of particle 3, the vapor pressure is high, and on the surface with negative curvature, that is, two TiO₂ The vapor pressure becomes low on the surface of the neck portion adjacent to the particle 3b. As a result, as shown in Fig. 17B, TiO in the neck portion₂SnO with higher vapor pressure than₂ is entered and condensed as shown in Fig. 17C, and sintering is performed by a vaporization-condensing mechanism.

Thus, when sintering is performed by the vaporization-condensation mechanism, TiO after sintering₂Particle spacing L₂is the distance L before sintering₀Since it is almost the same as , cracks or the like do not occur.

In this way, TiO is interposed on the surface of the substrate₂ In the composite member in which the particle layer is maintained, exposed to the outermost surface, TiO₂ SnO in the grain gap₂When the particles are filled and fired at 600°C or higher, cracks are not generated and TiO₂ Since the neck part between particles can be joined, abrasion resistance is improved.

(Comparative Example 7)

As in Example 6, SiO on the surface of the ceramic tile substrate of 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature 620° C.) is formed, and TiO₂ Sol and SiO₂ After mixing and stirring the sol, the aqueous solution was applied by spray coating, calcined at 750° C., and solidified by cooling to obtain a multifunctional material.

Also, TiO₂ The concentration of the sol is 4-6 wt% NH₃The pH was adjusted to 11 with an aqueous solution, and the crystal grain size of the particles was 0.01 μm as in Example 6, but SiO₂ The grain size of the particles was 0.008 μm, and slightly large particles were used.

The multifunctional material prepared in this way was subjected to an antibacterial test and abrasion resistance test, and the results compared with Example 6 are shown below (Table 7).

[Table 7]

Substrate = ceramic tile, binder = SiO₂-Al₂O₃-BaO frits,

Photocatalyst = TiO₂, interstitial particles = SiO₂ Sol (0.008μm), heat treatment 750°C

<img file="KR100357482B1_D0007.tif" />

As a result, SnO of 0.08 μm₂The result of the improvement of the wear resistance of the particles was 0.0035μm SnO₂It is weaker than when particles are used, and TiO₂ with SnO₂At a molar ratio of 60% or more to the total amount, there was no scratch or change even in about 40 perturbation tests.

For the antibacterial test, 0.0035μm and SnO₂As in the case of using particles, when the range is up to 20% or more, it is +++ as in the case of no addition, and stays in the drawing ++ at 60% or less. When more is added, TiO on the surface of the substrate₂The probability of covering the particles increased, and the antibacterial properties deteriorated, and at 100% it became -.

Therefore, 0.01 μm TiO₂ In the case of using particles, 0.008 μm of SnO₂It has been difficult to provide a multifunctional material excellent in both antibacterial and abrasion resistance by adding particles. The cause is SnO₂The vapor pressure of particles decreases as the particle size increases, and SnO remaining without vaporization₂TiO when the particle size is 0.0035μm₂On the other hand, TiO at 0.008 μm exists in the gap between particles and can improve bonding strength.₂Compared to the intergranular gap, SnO₂SnO because the particles are large₂The particles do not enter the interstices, but rather TiO₂It is thought that this is because the probability of coming out on a particle becomes high.

TiO from the above₂ SnO filling the gaps between particles₂The particle size is TiO₂ It is preferable that it is less than 4/5 with respect to a particle diameter.

(Example 8)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature 620°C) is formed, and TiO₂ After applying the sol aqueous solution by spray coating method, it is baked at 750°C and cooled to solidified SnO₂ After coating the aqueous sol solution by spray coating, heat treatment at 110° C. was performed to obtain a multifunctional material. At this time, TiO₂ For the sol aqueous solution, the same thing as in Example 6 was used, and SnO₂For the sol, 0.0035 µm was used.

The results of the antibacterial test and the abrasion resistance test on the multifunctional material prepared in this way are shown below (Table 8).

[Table 8]

Substrate = ceramic tile, binder = SiO₂-Al₂O₃-BaO frits,

Photocatalyst = TiO₂, interstitial particles = SiO₂ Sol (0.0035μm), heat treatment 750°C/110°C

<img file="KR100357482B1_D0008.tif" />

SnO for wear resistance test₂It improved with the increase of the amount, and by addition of 20% or more in molar ratio, there was no scratch or change even in 40 perturbation tests.

For the antibacterial test, when the range is up to 20% or more, it is +++ as in the case of no addition, and when it reaches 60%, it stays as ++. When more is added, TiO on the surface of the substrate₂ The probability of covering the particles increased, and the antibacterial properties deteriorated, and at 100% it became -.

In this test, SnO₂Since the sol is heat-treated at a low temperature of 110 DEG C, sintering by the vaporization-condensation mechanism shown in Example 6 does not occur. Although the wear resistance was nevertheless improved, this₂SnO having a smaller particle size than particles, that is, a large specific surface area, and excellent adsorption capacity₂ The particles are TiO₂By filling the gaps between the particles, TiO₂ It is thought that this is because the bonding between particles is strengthened.

(Example 9)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature 620°C) is formed, and TiO₂ After applying the aqueous sol solution by spray coating, the copper oxide aqueous solution is applied to the composite member that is fired at 750° C. and cooled and solidified, dried, and then fixed to the photocatalyst layer by irradiating light containing ultraviolet rays to reduce copper ions. Thus, a multifunctional material was obtained. Here, the irradiation lamp used a mercury lamp lamp.

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

The results of the antibacterial test and the abrasion resistance test on the multifunctional material prepared in this way are shown below (Table 9).

[Table 9]

Substrate = ceramic tile, binder = SiO₂-Al₂O₃-BaO frits,

Photocatalyst = TiO₂, interstitial particles = Cu (0.004μm), heat treatment 750°C / light reduction

<img file="KR100357482B1_D0009.tif" />

The abrasion resistance test improved with the increase in the amount of Cu, and there was no scratch or change even in 40 perturbation tests by addition of a molar ratio of 20% or more.

In the antibacterial test, when the range was up to 20% or more, it was +++ as in the case of no addition. In the case of Cu, since it has antibacterial activity itself, the deterioration of the antimicrobial property by adding a large amount was not observed.

However, when the amount of Cu added is too small, TiO₂ The photocatalytic action by the particle layer is dominant, and when the amount of Cu added is large, it will be considered that the action by Cu is dominant. In the case where the action of Cu alone is expected, since Cu is gradually eluted when used in a liquid, it is considered that the lifetime is shorter than in the case where there is no photocatalyst. Moreover, when the amount of Cu added becomes large, the cost increases by that much. Therefore, it is thought that it is meaningless to set the amount of Cu to a fairly large amount.

SnO by this example₂Not only oxides such as TiO, but also metals such as CU₂It was confirmed that it can be a particle filling the particle layer.

(Example 10)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature 620°C) is formed, and TiO₂After applying the aqueous sol solution by spray coating, baking at 950 ° C., applying an aqueous copper oxide solution to the cooled and solidified composite member, and then irradiating light containing ultraviolet rays to reduce copper ions while fixing to the photocatalyst layer. A multifunctional material was obtained.

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase transition from anatase to rutile in the heat treatment process. TiO₂was adjusted to 0.4 µm at the time of spray coating.

The multifunctional material prepared in this way was subjected to an antibacterial test and abrasion resistance test. In the abrasion resistance test, good results are shown in the temperature range even without additives. Even when Cu was added, there was no scratch or change in the 40 perturbation tests as in the case of no addition.

The antimicrobial test is shown in FIG. 18 . TiO when additive-free₂It is bad as + because is a rutile. Here, Cu was added to increase the antimicrobial properties. And not only when the BLB lamp is irradiated, but also when not irradiated, the Cu loading amount is 0.7 μg/cm 2 or more.

However, the Cu loading amount is dramatically improved if the drying process is performed after the copper acetate aqueous solution is applied and before the BLB lamp irradiation. This relationship is shown in FIG. 19 . It is considered that this is because the metal ion concentration at the time of photoreduction becomes high in the case of drying.

In addition, the Cu loading amount becomes maximum when the Cu application amount is optimized. (FIG. 20 and FIG. 21 are examples of copper acetate having a Cu concentration of 1 wt%), in the case of FIG. 20, 0.2 mg/cm 2 or more and 2.7 mg/cm 2 or less, 1.2 μg/cm 2 or more to make the application amount 0.7 μg/cm 2 or more In order to make it more than cm2, it is good to set it to 0.3mg/cm2 or more and 2.4mg/cm2 or less.

(Example 11)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature of 680°C) is formed, and TiO is formed thereon.₂After applying the aqueous sol solution by spray coating, firing at 950°C, applying an aqueous solution of silver nitrate to the cooled and solidified composite member, drying, and then irradiating light containing ultraviolet rays to reduce silver ions while fixing to the photocatalyst layer Thus, a multifunctional material was obtained.

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase transition from anatase to rutile in the heat treatment process. TiO₂was adjusted to 0.4 µm at the time of spray coating.

The multifunctional material prepared in this way was subjected to an antibacterial test and abrasion resistance test. In the abrasion resistance test, good results are shown in the temperature range even without additives. Even when Ag was added, there was no scratch or change in the 40 perturbation tests as in the case of no addition.

The antimicrobial test is shown in FIG. 69 . TiO when additive-free₂It is bad as + because is a rutile. The addition of Ag increased the antibacterial properties. And when the BLB lamp is not irradiated as well as when not irradiated, the antibacterial activity becomes ++ when the Ag loading is 0.05 μg/cm 2 or more, and the antibacterial activity becomes +++ when the Ag loading is 0.1 μg/cm 2 or more.

Therefore, in order to provide a multifunctional material excellent in both antibacterial and abrasion resistance, the Ag loading amount is preferably 0.05 μg/cm 2 or more, and more preferably 0.1 μg/cm 2 or more.

However, when there is a large amount of Ag supported, it is colored from multicolor to black, and it is bad in appearance. However, when the Ag loading amount is 1 μg/cm 2 or less, no coloration occurs.

From the above, the Ag loading amount is preferably 0.05 μg/cm 2 or more and 1 μg/cm 2 or less, and more preferably 0.1 μg/cm 2 or more and 1 μg/cm 2 or less.

(Example 12)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature of 680°C) is formed, and TiO₂After applying the sol aqueous solution by spray coating method, firing at 950°C, applying silver nitrate aqueous solution to the cooled and solidified composite member, drying, and then irradiating light containing ultraviolet rays to reduce silver ions while fixing in the photocatalyst layer Thus, a multifunctional material was obtained.

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase transition from anatase to rutile in the heat treatment process.

For the multifunctional material constructed in this way, TiO₂Abrasion resistance, antibacterial test, and contamination resistance test were performed by changing the film thickness of the to various values.

In the abrasion resistance test, all of the results within the range of 2 µm tested this time showed good results, and there were no scratches or changes even in 40 perturbation tests.

Regarding the antibacterial test, the film thickness was ++ under 0.1 μm or less, and +++ at 0.2 μm or more. Therefore, TiO₂ The film thickness is preferably 0.1 µm or more, preferably 0.2 µm or more.

(Example 13)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature of 620°C) is formed, and zinc chloride aqueous solution or TiO is formed thereon.₂ The aqueous solution of the sol was applied by spray coating, and after drying, an aqueous solution of silver nitrate was applied, and thereafter, the silver ion was reduced by irradiating light containing ultraviolet rays to fix it on the photocatalyst layer. Then, it was calcined at 950°C or higher and 1000°C or lower, and cooled and solidified to obtain a multifunctional material.

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase transition from anatase to rutile in the heat treatment process. In addition, it is thought that Ag fixed on the surface changed from black-brown to white with heat treatment, and changed to silver oxide during firing. However, Ag adhesion and fixation are discrete, and growth of Ag particles was hardly observed before and after firing by observation.

The multifunctional material prepared in this way was subjected to an antibacterial test and abrasion resistance test.

In the abrasion resistance test, good results are shown in this temperature range even without additives. Even with the addition of Ag, there was no scratch or change in the 40 perturbation tests as in the case of no addition.

The antimicrobial test is shown in FIG. 69 . TiO when additive-free₂It is bad as + because is a rutile. The addition of Ag increased the antibacterial properties.

(Example 14)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature 620°C) is formed, and TiO₂After applying the sol aqueous solution by spray coating method, firing at 900°C or more and 1000°C or less, the silver nitrate aqueous solution is applied to the cooled and solidified composite member, and then, the photocatalyst layer is irradiated with light containing ultraviolet rays to reduce silver ions. , and then, 0.1 mol/L of KI aqueous solution was applied thereon at a rate of 0.1 cc/cm 2 , and UV rays were again irradiated for about 5 seconds to obtain a multifunctional material. At this time, the loading amount of Ag was 2 μg/cm 2 .

By applying 0.1 mol/L of KI aqueous solution at a rate of 0.1 cc/cm 2 and irradiating with ultraviolet rays for 5 seconds, the multifunctional material, which was blackish-brown, was discolored to white, and the appearance was also improved.

(Example 15)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃A binder layer made of -BaO frit (softening temperature 620°C) is formed, and TiO₂Aqueous sol solution is applied by spray coating method, dried, baked at 820° C., and the multifunctional material obtained by cooling and solidifying is placed over time, and while irradiating the multifunctional material with light containing ultraviolet rays, it is collected from a public bath on the multifunctional material. One bath water was continuously dripped while circulating, and the bath water was observed. In order to compare the same device, it was also dripped on the base on which the photocatalyst layer was installed. In observation after 14 days, no special difference was observed in the turbid state of the bath water dripped on the multifunctional material compared to the bath water dripped on the substrate for installing a photocatalyst layer, and a difference in tofu smell was recognized. That is, the bath water installed on the substrate on which the photocatalyst layer is to be installed had a very strong smell of tofu, and slime-like viscous substances and organic sediments were observed on the substrate. neither was observed. Based on the above simulation, it is thought that the multifunctional material can be used as a pumice stone for artificial waterfalls or fountains with water circulation in parks, department stores, etc.

From the above description, the photocatalyst particles are fixed through a binder layer made of a material lower than the softening temperature of the substrate, and in particular, the photocatalyst particles constituting the surface layer of the photocatalyst layer are not filled in the binder layer. The surface becomes a state exposed to the outside, and the photocatalytic effect can fully be exhibited. In addition, among the photocatalyst particles, since a part of the particles constituting the lower layer of the photocatalyst layer is embedded in the binder layer, the holding power of the photocatalyst layer is greatly improved, and peeling or the like does not occur.

21 is a view showing the manufacturing process of another embodiment. In this embodiment, a thermoplastic material such as inorganic glass or a thermoplastic resin is used as the substrate 1, and a photocatalyst layer 2 is directly applied to the surface of the thermoplastic substrate 1 is forming

That is, as shown in the 21st (a), the thermoplastic base material 1 is prepared, and then TiO on the surface of the thermoplastic base material 1 as shown in the same figure (b).₂ A photocatalyst layer 2 made of photocatalyst particles such as particles is formed. Then, as shown in Fig. (c), the lower layer of the photocatalyst layer 2 on the side of the thermoplastic substrate is precipitated into the thermoplastic substrate by heat treatment, and the thermoplastic substrate is solidified to be buried in the thermoplastic substrate and firmly held. In addition, the photocatalyst particles 3 constituting the surface layer in contact with the outside air of the photocatalyst layer 2 are bonded by potential energy, intermolecular force or sintering.

Preferred conditions and the like for this embodiment are the same as those of the above embodiment, but specific examples will be described below.

(Example 16)

SiO on the surface of a ceramic tile base with 150 mm on each side₂-Al₂O₃-Na/K₂15% TiO on the surface of the glass substrate with O composition₂ The sol aqueous solution is applied by spray coating and the film thickness is 0.8μm TiO₂to form a layer, followed by TiO₂The laminated glass substrate is placed in a ceramic mold with good formation, and is heated and fired with a roller Haas kiln at different ambient temperatures for each example, and then cooled and solidified to obtain a multifunctional glass.

Here, TiO₂The sol aqueous solution is, for example, TiCl₄Anatase-type TiO having a crystal grain size of 0.007 to 0.2 μm obtained by hydrolyzing in an autoclave under hydrothermal conditions in the range of 100 to 200° C.₂is dispersed in an acidic aqueous solution such as nitric acid or hydrochloric acid or in a basic aqueous solution such as ammonia in a sol state by several % to several tens%. , trimethylolpropane, etc. are added in the range of 0.5% or less. Also, TiO₂ The particle size of the sol was calculated from the integrated width of powder X-ray diffraction by image processing of SEM observation.

In addition, although the coating method was performed by the spray coating method, it is expected that the same result will be obtained also with the dip coating method and the spin coating method.

The obtained multifunctional glass was evaluated for antibacterial and abrasion resistance.

For the antibacterial property, the sterilization effect was tested against Escherichia coli W3110 strain. 0.15 ml (1-5×104 CFU) of the bacterial solution was dropped onto the outermost surface of a multifunctional glass previously sterilized with 70% ethanol, placed on a glass plate 10×10 cm, and brought into close contact with the outermost surface of the glass substrate to obtain a sample. After irradiating a white light (3500 lux) for 30 minutes, the bacteria solution of the irradiated sample and the sample maintained under light-shielding conditions was wiped with sterile gauze, recovered with 10 ml of physiological saline, and the survival rate of the bacteria was obtained as an evaluation index.

Regarding abrasion resistance, perturbation abrasion using a plastic eraser was performed, and the change in appearance was comparatively evaluated.

SiO in the following (Table 10)₂-Al₂O₃-Na/K₂It shows the change in antibacterial and abrasion resistance according to the change of the firing temperature when a glass substrate of O composition is used.

[Table 10]

Substrate = SiO₂-Al₂O₃-Na/K₂O

Photocatalyst = TiO₂

<img file="KR100357482B1_D0010.tif" />

+++: Survival rate of E. coli less than 10%

++ : Survival rate of E. coli 10% or more but less than 30%

+ : Survival of E. coli by more than 30% and less than 70%

- : E. coli survival rate over 70%

: No change for 40 round trips

: A scratch occurs in 10 to 40 perturbations, and the photocatalyst layer (TiO₂layer) is peeled

: A scratch occurs in 5 to 10 perturbations, and the photocatalyst layer (TiO₂layer) is peeled

×: A scratch occurs in perturbation of 5 times or less, and the photocatalyst layer (TiO₂layer) is peeled

Here, SiO₂-Al₂O₃-Na/K₂The specific gravity of the glass substrate of the O composition was 2.4 and the softening temperature was 680 ° C. In addition, TiO obtained in (Table 10)₂ is No. For 1 to 3, it is an anatase type, and the specific gravity is 3.9, No. About 4.5, it was a rutile type, and specific gravity was 4.2.

In (Table 10), No. 1 indicates that the sintering temperature is only 20°C higher than the softening temperature of the glass substrate and the viscosity of the glass substrate is not sufficiently low, so anatase-type TiO constituting the lowest layer of the photocatalyst layer₂ The particles are not sufficiently embedded in the glass substrate, so that in the abrasion resistance test, scratches occur and peel off after 5 to 10 perturbations. In addition, with respect to antibacterial properties, it is an anatase type having excellent photocatalytic activity and TiO at 300°C or higher.₂According to the observation of TG-DTA in Joule, organic components are almost decomposed and vaporized, and TiO₂ It is interpreted that the dispersant such as the surface treatment agent adhering to the surface is vaporizing, but at a firing temperature of 700°C and a treatment temperature slightly higher than that, an excellent value of ++ was obtained.

No. 3 to 5 were cases where the firing temperature was 800°C or higher and 1000°C or lower, but in any case, the durability did not change even in 40 or more perturbation tests, and was extremely excellent. The cause is the surface TiO₂ Generation of the neck portion is taken into account by the initial firing of the particles. In the case of treatment at 1100°C, TiO on the surface of the multifunctional glass taken out from the roller hearth kiln after cooling and solidification₂There is a crack in the floor. This is TiO₂ Judging from the TMA measurement of the test piece, TiO₂ It is considered to be due to steam sintering with significant optimal shrinkage of the particles.

No. In 4 and 5, both antibacterial properties were poor. Two causes are considered here. One is TiO₂ Another is that the sintering temperature is 300°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate is too low to form TiO constituting the photocatalyst layer due to the phase transition of the particles to the rutile type.₂ It is considered that this is because the particles are embedded in the glass substrate. Here, TiO₂ It cannot be considered that the only cause of the phase transition of the particles to the rutile type is. Rutile TiO₂ also in anatase-type TiO₂It is poor because it has some photocatalytic activity. For example, direct TiO on a porous alumina substrate₂ After the sol was spray coated and calcined at 950°C, the antibacterial property of the solidified material by cooling was +. Therefore, the sintering temperature is 300°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate is too low for TiO constituting the photocatalyst layer.₂ It is also interpreted that the particle is buried in the glass substrate as one cause.

In addition, a mixed layer of Ti and Si was observed by elemental analysis of Ti and Si (main component of glass substrate) by EBMA or the like in the cross-sectional direction of the sample, and TiO, which is a photocatalytic particle₂was confirmed to be buried.

Example 16 above, that is, at least the photocatalyst is TiO₂ Glass substrate is SiO₂-Al₂O₃-Na/K₂In the case of O composition, the following was confirmed.

: When the multifunctional glass is manufactured under the condition that the firing temperature is higher than 20°C than the softening temperature of the glass substrate and not higher than 300°C, a multifunctional glass with good antibacterial and abrasion resistance can be produced. The reason is that the viscosity of the glass substrate in the above temperature range is TiO₂It is thought that this is because it can be adjusted to a value that can be properly embedded in the glass substrate.

: The multifunctional glass prepared in 1 is TiO₂ Burial of the particles as a glass substrate was confirmed.

: In all cases where the firing temperature was 800°C or more and 1000°C or less, the abrasion resistance did not change even in 40 or more perturbation tests, and was extremely excellent. TiO₂ It is thought that it is due to the strong bonding caused by the generation of the neck part between the particles.

(Example 17)

10×100×5 SiO₂-Al₂O₃-15% TiO on the surface of the glass substrate with PbO composition₂ A sol aqueous solution (same as in Example 16) was applied by spray coating, and TiO having a film thickness of 0.8 µm₂to form a layer, followed by TiO₂The laminated glass substrate was placed in a mold with good releasability made of ceramic, and after heating and firing at different ambient temperatures for each Example using a roller Haas Kilun, it was cooled and solidified to obtain a multifunctional glass.

SiO in (Table 11) below₂-Al₂O₃- It shows the change in antibacterial and abrasion resistance according to the change of the firing temperature when the glass substrate of the PbO composition is used.

[Table 11]

Substrate = SiO₂-Al₂O₃-PbO glass,

Photocatalyst = TiO₂

<img file="KR100357482B1_D0011.tif" />

Here, SiO₂-Al₂O₃The softening temperature of the glass substrate of the -PbO composition was 540° C., and the specific gravity was 3.8. Also obtained TiO₂All of the crystalline forms were anatase form.

In the abrasion resistance test of (Table 11), No. No. 6 was scratched and peeled off with 10 or less perturbations, but No. 7 and 8 were scratched even with more than 10 perturbations, and No. In 9 and 10, good results were obtained that did not cause scratches even with 40 or more perturbations.

No. The reason that there were no scratches even after perturbation for more than 40 times at 9 and 10 is because the firing temperature is 800°C or higher, so TiO₂ A neck is created between the particles, and TiO₂ It is thought that it is because the particle|grains were strongly couple|bonded with each other.

No. The anatase type constituting the lowermost layer of the photocatalyst layer because the sintering temperature was only 20°C higher than the softening temperature of the glass substrate and the viscosity of the glass substrate was not sufficiently low, which was scratched by 6 to 10 or less perturbations. TiO₂ It is considered that the particles were not sufficiently embedded in the glass substrate.

Regarding this, No. The difference between the firing temperature and the softening temperature of the glass substrate, which did not reach the temperature at which the neck part was formed, showed that the glass substrate was not damaged even after 7, 8 to 10 or more perturbations.₂It is thought that this is because it has been corrected to a value that can be properly embedded in the glass substrate.

On the other hand, in the antimicrobial test of (Table 11), No. 6 to 9 were obtained with good results with +++ or ++, but No. 10 was +. This is because the firing temperature is 320°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate is too low, so TiO constituting the photocatalyst layer₂ It is considered that this is because the particles have been embedded in the glass substrate.

(Example 18)

SiO₂-Al₂O₃- 15% TiO on a 100×100×5 glass substrate with a BaO composition₂An aqueous sol solution (same as in Example 1) was applied by spray coating and TiO having a film thickness of 0.8 μm₂layer was formed. After that, TiO₂The laminated glass substrate was placed on a ceramic mold with good releasability, and after heating and firing at different ambient temperatures with silicon dioxide for each Example, cooling and solidification was performed to obtain a multifunctional glass.

Table 12 below shows the change in antibacterial and abrasion resistance according to the change in the firing temperature of the multifunctional glass.

[Table 12]

Substrate = SiO₂-Al₂O₃-BaO glass

Photocatalyst = TiO₂

<img file="KR100357482B1_D0012.tif" />

Here, SiO₂-Al₂O₃-The softening temperature of the glass substrate of the BaO composition is 620°C, the specific gravity is 2.8, and TiO on the multifunctional glass₂The crystalline form of No. 11 to 13 are anatase type, No. 14 was rutile.

In the abrasion resistance test of (Table 12), No. No. 11 was scratched and peeled off with 5 or less perturbations, but No. 12 shows no damage even with 10 or more perturbations, and No. 13 and 14, good results were obtained with no flaws even with more than 40 perturbations.

No. 13, 14 and 40 or more perturbations were not scratched because the firing temperature was 800°C or higher, so TiO₂ A neck between particles is created and TiO₂It is thought that it is because the particle|grains were strongly couple|bonded with each other.

No. In the case of 11 to 10 perturbations or less, scratches and peeling occurred because the firing temperature was only 20°C higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate was not sufficiently low. type TiO₂It is thought that it is because the particle|grains were not fully embedded in the glass base material.

Regarding this, No. The difference between the sintering temperature and the softening temperature of the glass substrate was the difference in the viscosity of the glass substrate that did not reach the part where the neck part was formed that did not get damaged even after perturbation of 12 to 10 times or more.₂It is thought that this is because the value was adjusted to a value that can be properly embedded in the glass substrate.

On the other hand, in the antimicrobial test of (Table 12), No. In 11 to 13, good results were obtained with +++ or ++, but No. 14 became -. This is TiO₂TiO constituting the photocatalyst layer because the rutile type, the firing temperature is higher than 320°C than the softening temperature of the glass substrate, and the viscosity of the glass substrate is too low₂It is thought that it is due to two causes that the particle|grains have been buried in the glass base material.

(Example 19)

15% TiO on the surface of a glass substrate of 100 × 100 × 5 mm with different specific gravity for each example₂The sol aqueous solution was spray coated with TiO having a film thickness of 0.8°C.₂to form a layer, followed by TiO₂ The laminated glass substrate was placed in a ceramic mold with good releasability, and after heating and firing at an ambient temperature of 750° C. with a roller Hasskillun, it was cooled and solidified to obtain a multifunctional glass. Table 13 below shows the change in antibacterial and abrasion resistance according to the change in specific gravity of the glass substrate of the multifunctional glass of vitality.

[Table 13]

Photocatalyst layer = TiO₂

<img file="KR100357482B1_D0013.tif" />

Regarding the antibacterial test, No. All of 15 to 18 were +++, and good results were obtained. In any case, the firing temperature is higher than the softening temperature of the glass substrate in the range of 30°C to 300°C, and the range of the difference between the firing temperature and the softening temperature of the glass substrate is the viscosity of the glass substrate with TiO.₂It is thought that this was because the value was adjusted to a value that could be properly embedded in the glass substrate. Regarding wear resistance, No. No. 15 was scratched and peeled off with 5 or less perturbations, but No. 16-18 showed no flaws even after more than 10 perturbations.

As a cause, No. In 15, unlike the others, the specific gravity of the glass substrate is TiO₂Anatase-type TiO constituting the lowermost layer of the photocatalyst layer because it is larger than the specific gravity of₂ It is thought that this is because the particles could not be sufficiently embedded in the glass substrate.

Therefore, the wear resistance of the multifunctional glass is₂The specific gravity of the glass substrate is affected, and the specific gravity of the glass substrate is TiO₂ It turned out that it deteriorated when it was larger than specific gravity.

(Example 20)

SiO with 150 mm each side₂-Al₂O₃TiO on the surface of a glass substrate with a -BaO composition (softening temperature of 620°C)₂Sol and SiO₂An aqueous solution in which the sol was mixed and stirred was applied by a spray coating method, calcined at 750° C., and solidified by cooling to obtain a multifunctional material.

Also, TiO₂Sol concentration is 4-6 wt% NH₃ It is prepared to pH 11 with an aqueous solution, and TiO₂ The grain size of the particles is 0.01μm, SnO₂ The grain size of the particles was 0.0035 μm.

Regarding the multifunctional glass made in this way, TiO₂with SnO₂SnO for the sum of₂The results of the antibacterial test and the abrasion resistance test when the amount (molar ratio) was varied in various ways are shown in Table 14 below.

[Table 14]

Substrate = SiO₂-Al₂O₃-BaO glass,

Photocatalyst = TiO₂, interstitial particles = SnO₂(0.0035㎛)

<img file="KR100357482B1_D0014.tif" />

SnO for wear resistance test₂It improved with an increase in the amount of , and there was no scratch or change even in 40 perturbation tests by addition of 10% or more.

In the antibacterial test, it was +++ in the range up to 20%, as in the case of no addition, and ++ in the range up to 60%. When more is added, TiO on the surface of the glass substrate₂The probability of covering the particles was high, and the antibacterial properties were deteriorated, and at 100% it was -.

Therefore, SnO₂TiO in the molar ratio₂with SnO₂If it is 10% or more and 60% or less, preferably 10% or more and 20% or less of the total amount, it is possible to provide a multifunctional glass excellent in antibacterial and abrasion resistance.

Here, the wear resistance is SnO₂The improvement with an increase in the amount of is by the mechanism described with reference to FIG. 17 .

In this way, TiO through the glass substrate₂In the composite member in which the particle layer is maintained, exposed to the outermost surface and TiO₂SnO in the interstices of the particles₂When the particles are filled and fired at 600°C or higher, cracks are not generated and TiO₂Since the neck portion between particles can be joined, the abrasion resistance property is improved.

(Comparative Example 21)

In the same manner as in Example 20, SiO of 150 mm on each side₂-Al₂O₃TiO on the surface of a glass substrate with a -BaO composition (softening temperature of 620°C)₂Sol and SiO₂An aqueous solution in which the sol was mixed and stirred was applied by a spray coating method, calcined at 750° C., and solidified by cooling to obtain a multifunctional material.

Also TiO₂Sol concentration is 4-6 wt% NH₃ It was prepared at pH 11 with an aqueous solution, and TiO₂The grain size of the particles is 0.01 μm as in Example 5, but SnO₂The crystal grain size of the particles was used as large particles of 0.008μm.

The multifunctional glass thus made was subjected to an antibacterial test and abrasion resistance test, and the results compared with Example 5 are shown in Table 15 below.

[Table 15]

Substrate = SiO₂-Al₂O₃-BaO glass,

Photocatalyst = TiO₂, interstitial particles (0.008μm), heat treatment 750°C

<img file="KR100357482B1_D0015.tif" />

As a result, SnO of 0.008 μm₂The effect of improving the wear resistance of the particles is 0.0035μm SnO₂It is weaker than when particles are used, and TiO₂Particles and SnO₂The molar ratio to the total of the particles was 60% or more, and there was no scratch or change even in about 40 perturbation tests.

For the antibacterial test, 0.0035 μm SnO₂As in the case of using particles, up to 20% was +++ as in the case of no addition, and up to 60% was ++. When more is added, TiO on the surface of the glass substrate₂The probability of covering the particles became high, and the antibacterial property deteriorated, and at 100% it was -.

Therefore, 0.01 μm TiO₂In the case of using particles, 0.008 μm of SnO₂It is difficult to provide a multifunctional glass excellent in both antibacterial and abrasion resistance by adding particles. The cause is SnO₂The vapor pressure of the particles becomes smaller as the particle size increases. Sn remaining without vaporization₂2 TiO in the case of 0.0035μm particle size₂On the other hand, TiO at 0.008 μm exists in the gap between particles and can improve bonding strength.₂Compared to the intergranular gap, SnO₂Because the particles are large, SnO₂The particles do not enter the interstices, but rather TiO₂ It is thought that this is because the probability of coming into the particle phase becomes high.

TiO from above₂SnO filling the gaps between particles₂The particle size is TiO₂It is preferable that it is less than 4/5 with respect to a particle diameter.

(Example 22)

SiO with 150 mm each side₂-Al₂O₃TiO on the surface of the glass substrate with -BaO composition (softening temperature 620°C)₂A sol aqueous solution is applied by spray coating, calcined at 750° C., and cooled to solidified composite members with SiO₂A sol aqueous solution was applied by spray coating and heat-treated at 110° C. to obtain a multifunctional material. At this time, TiO₂The same thing as in Example 5 was used for the sol aqueous solution, and SnO₂For the sol, 0.0035 µm was used.

The results of the antibacterial and abrasion resistance tests on the multifunctional glass made in this way 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

<img file="KR100357482B1_D0016.tif" />

SnO for wear resistance test₂It improved with the increase of the amount, and there was no scratch or change even in 40 perturbation tests by addition of 20% or more in molar ratio.

In the antibacterial test, it was +++ in the range up to 20%, as in the case of no addition, and ++ in the range up to 60%. When more is added, TiO on the surface of the glass substrate₂The probability of covering the particles became high, and the antibacterial property deteriorated, and at 100% it was -.

In this test, SnO₂Since the sol is heat-treated at a low temperature of 10°C, sintering by the vaporization-condensation mechanism shown in Example 5 does not occur. Nevertheless, the wear resistance was improved, but this₂SnO having a smaller particle size than particles, that is, having a large specific surface area and excellent adsorption capacity₂The particles are TiO₂TiO by filling the gaps between the particles₂It is thought that this is because the bonding between particles is strengthened.

(Example 23)

SiO with 150 mm each side₂-Al₂O₃TiO on the surface of the glass substrate with -BaO composition (softening temperature 620°C)₂A sol aqueous solution is applied by spray coating, fired at 750° C., and an aqueous copper oxide solution is applied to the solidified composite member by cooling, dried, and then irradiated with light containing ultraviolet rays to reduce copper ions while reducing copper ions to the photocatalyst layer. Fixed to obtain a multifunctional glass. Here, the irradiation lamp used a mercury lamp lamp.

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

The results of the antibacterial test and the abrasion resistance test on the multifunctional material prepared in this way are shown below (Table 17).

[Table 17]

Substrate = SiO₂-Al₂O₃-BaO glass,

Photocatalyst = TiO₂, interstitial particles = Cu (0.004μm), heat treatment 750°C / light reduction

<img file="KR100357482B1_D0017.tif" />

The abrasion resistance test improved with the increase of the Cu content, and there was no scratch or change even in 40 perturbation tests by addition of a molar ratio of 20% or more.

In the antibacterial test, when the range was up to 20% or more, it was +++ as in the case of no addition. In the case of Cu, since it has antimicrobial activity itself, the deterioration of the antimicrobial property by adding a large amount was not observed.

However, when the amount of Cu added is too small, TiO₂The photocatalytic action by the particle layer is dominant, and when the amount of Cu added is large, it will be considered that the action by Cu is dominant. When the action of Cu alone is expected, it is considered that the lifetime is shorter than in the case where there is no photocatalyst because Cu is gradually eluted when used in a liquid. Moreover, when the amount of Cu added becomes large, the cost also increases by that much. Therefore, it is thought that it is meaningless to set the amount of Cu to a fairly large amount.

SnO by this example₂Not only oxides such as TiO, but also metals such as Cu₂It was confirmed that it can be a particle filling the particle layer.

(Example 24)

SiO with 150 mm each side₂-Al₂O₃TiO on the surface of the glass substrate with -BaO composition (softening temperature 620°C)₂After applying the sol aqueous solution by spray coating method, firing at 950 ° C., coating the copper oxide aqueous solution on the cooled and solidified composite member, irradiating light containing ultraviolet rays to reduce copper ions while fixing to the photocatalyst layer, which is a multifunctional material got

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase transition from anatase to rutile in the heat treatment process. TiO₂was adjusted to 0.4 µm at the time of spray coating.

An antibacterial test and abrasion resistance test were performed on the glass prepared in this way. In the abrasion resistance test, even without addition, good results were obtained in the temperature range. Even when Cu was added, there was no scratch and no change in the perturbation test 40 times as in the case of no addition.

The antimicrobial test is shown in FIG. 22 . TiO when additive-free₂It is bad as + because is a rutile. Here, Cu was added to increase the antimicrobial properties. And, not only when irradiated with a BLB lamp, but also when not irradiated, the antibacterial activity becomes ++ when the Cu loading amount is 0.7 μg/cm 2 or more, and the antibacterial activity becomes +++ when the Cu loading amount is 1.2 μg/cm 2 or more.

From the above, in order to provide a multifunctional glass excellent in both antibacterial and abrasion resistance, the Cu loading amount is preferably 0.7 μg/cm 2 or more, and more preferably 1.2 μg/cm 2 or more.

However, the Cu loading amount is dramatically improved when the drying step is performed after the copper acetate aqueous solution is applied and before the BLB lamp irradiation. 23 shows this relationship. It is thought that this is because the metal ion density|concentration at the time of the case of drying becomes high at the time of photoreduction.

In addition, the Cu loading amount becomes maximum when the Cu application amount is optimized. (FIG. 24 is an example of copper acetate having a Cu concentration of 1 wt%), in the case of FIG. 24, in order to make the loading amount 0.7 μg/cm 2 or more, the application amount is 0.2 μg/cm 2 or more and 2.7 μg/cm 2 or less, and the loading amount is 1.2 μg In order to set it to /cm2 or more, the application amount may be 0.3μg/cm2 or more and 2.4μg/cm2 or less.

(Example 25)

SiO with 150 mm each side₂-Al₂O₃TiO on the surface of a glass substrate with a -BaO composition (softening temperature of 680°C)₂After applying the aqueous sol solution by spray coating, firing at 950°C, applying an aqueous silver nitrate solution to the cooled and solidified composite member, drying, and then irradiating light containing ultraviolet rays to reduce silver ions while fixing to the photocatalyst layer Thus, a multifunctional material was obtained.

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase transition from anatase to rutile in the heat treatment process. TiO₂was adjusted to 0.4 µm at the time of spray coating.

The multifunctional glass prepared in this way was subjected to an antibacterial test and abrasion resistance test. In the abrasion resistance test, good results are shown in the temperature range even without additives. Even when Ag was added, there was no scratch or change in the 40 perturbation tests as in the case of no addition.

The antimicrobial test is shown in FIG. 25 . TiO when additive-free₂It is bad as + because is a rutile. The addition of Ag increased the antibacterial properties. And when the BLB lamp is not only irradiated, but also when not irradiated, the antibacterial activity becomes ++ when the Ag loading is more than 0.05 μg/cm 2 , and when the Ag loading is 0.1 μg/cm 2 or more, the antibacterial activity becomes +++.

Therefore, in order to provide a multifunctional glass excellent in both antibacterial and abrasion resistance, the Ag loading amount is preferably 0.05 μg/cm 2 or more, and more preferably 0.1 μg/cm 2 or more.

However, when there is a large amount of Ag supported, it is colored from multicolor to black, and it is bad in appearance. However, when the Ag loading amount is 1 μg/cm 2 or less, no coloration occurs.

From the above, the Ag loading amount is preferably 0.05 µg/cm 2 or more and 1 µg/cm 2 or less, and more preferably 0.1 µg/cm 2 or more and 1 µg/cm 2 or less.

(Example 26)

SiO with 150 mm each side₂-Al₂O₃TiO on the surface of a glass substrate with a -BaO composition (softening temperature of 680°C)₂After applying the sol aqueous solution by spray coating, firing at 950 ° C., applying an aqueous silver nitrate solution to the cooled and solidified composite member, drying, and then irradiating light containing ultraviolet rays to reduce silver ions while fixing to the photocatalyst layer Thus, a multifunctional glass was obtained.

At this time, the irradiation lamp used a BLB lamp, and irradiated for several minutes. TiO₂was a phase change from anatase to rutile in the heat treatment process.

For the multifunctional glass prepared in this way, TiO₂Abrasion resistance, antibacterial test, and contamination resistance test were performed by changing the film thickness of the to various values.

In the abrasion resistance test, good results were all shown within the range of 2 µm tested here, and there was no scratch or change even in 40 perturbation tests.

Regarding the antibacterial test, it was ++ with a film thickness of 0.1 mu m or more, and +++ with a film thickness of 0.2 mu m or more. Therefore, TiO₂ The film thickness is preferably 0.1 µm or more, preferably 0.2 µm or more.

From the above description, since the photocatalyst particles are fixed to the thermoplastic substrate, and in particular, the photocatalyst particles constituting the surface layer of the photocatalyst layer are not buried in the thermoplastic substrate, the photocatalyst particles are substantially in a state whose surface is exposed to the outside, A photocatalytic effect can be fully exhibited. In addition, among the photocatalyst particles, since a part of the particles constituting the lower layer of the photocatalyst layer is embedded in the thermoplastic substrate, the holding power of the photocatalyst layer is greatly improved, and peeling or the like does not occur.

26 and 27 are conceptual views of a basic profile when the cross-sectional direction of the multifunctional material is observed with an EBMA (electron beam microanalyzer). As can be seen from these figures, a region where the concentration of the components constituting the photocatalyst layer 2 is almost constant on the surface in contact with the outside air continues (region A), and then the component for firing the photocatalyst layer is decreases. In addition, the components constituting the amorphous layer (binder layer) are absent or present on the surface, and the concentration increases toward the inside. Thus, it becomes almost constant as it goes up to a certain film thickness (region B). Here, region A is defined as a photocatalyst layer, region B is defined as an amorphous layer, and region C in the middle thereof is defined as an intermediate layer. However, FIG. 26 is a conceptual diagram for convenience of explanation only, and in reality, as shown in FIG. 7 , the concentration constant in FIG. 26 is often accompanied by variations in concentration due to reasons of the manufacturing process. In this case, as shown in FIG. 27, the portions reaching the minimum concentration of the regions (regions A' and B') corresponding to the predetermined regions are separated from the regions A' and C', B' and C', respectively. looked at the border.

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

The thickness of this intermediate layer can be changed by controlling the speed and time during which the photocatalytic particles can move into the softening amorphous layer. The movement speed can be controlled by understanding the specific gravity difference between the photocatalyst particles and the amorphous layer, the firing temperature, the atmospheric pressure, and the like. Also, the transfer time can be changed by changing the holding time at the temperature at which the amorphous material softens.

By setting the thickness of the intermediate layer to 1/3 or more of the thickness of the photocatalyst layer, the adhesion can be increased.

Hereinafter, specific examples will be described.

(Example 27)

SiO on a 10 cm square alumina substrate₂-Al₂O₃-Na/K₂An O-based amorphous layer is formed by spray coating, and after drying and calcination, TiO having an average particle diameter of 0.01 μm₂Anatase-type TiO with a film thickness of 0.2 μm, 0.5 μm, and 1 μm by applying an aqueous sol solution by spray coating, and calcining it at 850° C. by changing the holding time.₂layer was formed. Subsequently, this anatase-type TiO₂ A copper acetate aqueous solution was applied to the thin film by a spray coating method, and then, a sample was obtained by light reduction (the light source was a 20 watt BLB lamp, 10 cm from the light source to the sample, irradiation time 30 seconds). The obtained sample was evaluated for film thickness measurement by elemental analysis (Ti, Si) of the cross section by EBMA, and for antibacterial and abrasion resistance.

For the antibacterial properties, E. coli (Escherichia coli W3110 strain) was tested. 0.15 ml (1-50000 CFU) of the bacterial solution was dripped onto the outermost surface of the multifunctional material previously sterilized with 70% ethanol, placed on a glass plate (10×10 cm), and brought into close contact with the outermost surface of the substrate to obtain a sample. After irradiating a white light (3500 lux) for 30 minutes, the bacterial solution of the irradiated sample was wiped with sterile gauze, recovered with 10 ml of physiological saline, and the survival rate of the bacteria was obtained as an evaluation index. The evaluation criteria are the same as in the case of the previous year (Table 1).

A result is put together in (Table 18), and is shown. All were +++ for antibacterial properties.

Abrasion resistance also showed good results as or . In particular, the ratio of the thickness of the intermediate layer to the thickness of the photocatalyst layer was in all samples of 1/3 or more.

[Table 18]

<img file="KR100357482B1_D0018.tif" />

(Comparative Example 28)

TiO with an average particle diameter of 0.01 μm₂ The sol ammonia dispersion was applied on a 10 cm square alumina substrate by a spray coating method, and it was baked at 850 DEG C to form an anatase-type TiO2 layer having a thickness of 1 mu m. Subsequently, this anatase-type TiO₂ A copper acetate aqueous solution was applied to the thin film by a spray coating method, and then, a sample was obtained by light reduction (the light source was a 20-watt BLB lamp, the distance from the light source to the sample was 10 cm, the irradiation time was 30 seconds). The obtained samples were evaluated for antibacterial properties and abrasion resistance.

The progress and antibacterial property were good at +++, but the abrasion resistance was insufficient at Δ.

From the above description, the photocatalyst layer is maintained through the amorphous layer on the surface of the substrate, the upper layer of the photocatalyst layer is exposed so as to be in contact with the outside air, and the photocatalyst layer is a multifunctional material having a photocatalytic function in which particles are bonded to each other. The photocatalyst layer has an intermediate layer in which the concentrations of both components continuously change therebetween, thereby increasing the adhesion between the photocatalyst film layer and the substrate and improving the peeling resistance. In addition, by setting the thickness of the intermediate layer to 1/3 or more of the thickness of the photocatalyst layer, adhesion can be increased.

Next, a case in which the photocatalyst layer 2 is formed by sintering will be described. 1a is a conventional TiO₂ It is a view showing the state of the particles before sintering, (b) is a view showing the state after sintering, and as shown in Fig. 1a, TiO on the surface of the substrate 1₂ When the sol containing the particles 3 is coated and heat-treated (sintered) to increase the film strength, cracks 2a are likely to occur as shown in FIG. 1B .

The cause is the rutile type, and the phase transition causes volume shrinkage (the density becomes high), and TiO before sintering₂ The gap between the particles 101 is L₀After the former was sintered into a rutile type, the spacing between particles was L due to volume diffusion of the other side.₁(L₁&lt;L₀), and it is considered that cracks occur as a result.

Here, TiO bonded by sintering₂ SnO on the neck of particle 3₂by condensing and thickening the neck portion of TiO₂ The bond between the particles 3 is strengthened, and as a result, the film strength is increased.

In order to form the photocatalyst layer 2 as described above, TiO₂ SnO in the sol₂The sol is mixed and stirred, applied on the substrate 1, and heat-treated (sintered) in a predetermined temperature range.

Also, TiO₂The sol concentration is about 4 to 6 wt%, and NH₃ Adjust to pH 11 in solution, TiO₂ The average primary particle diameter of the particles is 0.01 μm (10 nm), and SnO₂The sol concentration is about 10 wt%, and NH₃ Adjust to pH 11 in solution, SnO₂ The average primary particle size of the particles is 0.0035 µm. The average primary particle size shown here is that of the crystallite size (primary particle) obtained from the half width of the diffraction line of XRD (X-ray diffraction).

Here, SnO₂is TiO₂Since the vapor pressure is higher than that, TiO₂ The spacing of the particles 3 is L as shown in Fig. 17a.₀However, the vapor pressure is high on the surface having a positive curvature of the titanium oxide particles 3, and the vapor pressure is lowered on the surface having a negative curvature, that is, the surface of the neck portion where the two titanium oxide particles 3 are in contact with each other. As a result, as shown in FIG. 17B, SnO has a higher vapor pressure than titanium oxide in the neck.₂, and condensed as shown in Fig. 17C, and sintering is performed by a vaporization-condensation mechanism.

Thus, when sintering is performed by the vaporization-condensation mechanism, TiO after sintering₂ particle spacing L₂is the distance L before sintering₀Since it is almost the same as , cracks do not occur.

As described above, TiO before and after sintering₂The photoactivity (R) as a photocatalytic film without substantially changing the particle spacing₃₀) to 50% or more, as shown in FIG. 28, SnO₂TiO₂It is necessary to set the ratio to 20-70%.

In addition, the compounding ratio represents the weight ratio of the solid content contained in each sol. In addition, evaluation of photoactivity decomposes methyl mercaptan, and the removal rate (R) after 30 minutes of light irradiation₃₀) was used as an index. Specifically, in an 11 liter glass container, a 150 mm tile with a photocatalytic film on each side is placed at a distance of 8 cm from the light source (BLB fluorescent lamp 4W), and after confirming that there is no adsorption during light blocking, the fluorescent lamp is turned on, and gas chromatography is performed. Concentration changes were measured over time by means of a graph.

where R₃₀=(X₀-X₃₀)/X₀ × 100%

However, X₀= Initial concentration [ppm], X₃₀=Concentration after 30 minutes [ppm]

In addition, for evaluation of film strength, perturbation abrasion using a plastic eraser was performed, and the external appearance change was comparatively evaluated. Evaluation criteria ,,,× are the same as in the previous (Table 1).

In addition, Figure 29 is a graph showing the relationship between the heat treatment temperature and photoactivity, TiO₂When an organic stabilizer is added to the sol, the photoactivity is low, but in any case, the heat treatment temperature is 300 to 850°C. It is difficult to generate activity when the heat treatment temperature is less than 300°C, and when it exceeds 850°C, TiO₂This is because the structure of is changed from anatase to rutile.

From the above description, it is applied to a tile containing titanium oxide particles and a substance having a vapor pressure higher than that of titanium dioxide and sintered at a firing temperature to form a film by sintering by a vaporization-condensation mechanism. The gaps between the titanium particles are almost the same, so cracks are less likely to occur. In addition, in the neck portion between the titanium oxide particles, SnO₂ Since the etc. are condensed, the peeling strength of a film becomes high.

In particular, SnO₂addition amount (TiO)₂By 20 to 30%, both film strength and photoactivity can be satisfied, and sufficient photoactivity can be obtained by heat treatment in the range of 300°C or higher and 850°C or lower.

Then, R by gas chromatography₃₀In the method of measuring , the measuring device is expensive, and only one sample can be measured with respect to one device, so the efficiency is poor.

In addition, metal such as Pt is TiO₂It is known that the photoactivity is improved by supporting the photocatalyst, but it is difficult to determine the correct level of photoactivity in the photocatalytic thin film of this structure due to the effect of gas adsorption by metal.

In addition, the activity of the photocatalyst thin film formed on the surface of a tile or the like as a wall surface after it is once constructed cannot be measured by gas chromatography.

In addition, as an evaluation method that does not use gas chromatography, a method of examining the survival rate after light irradiation of bacteria killed by a photocatalyst is also considered. It is difficult to accurately determine the photoactivity because bacteria are killed even by its antibacterial power. Here, it is also possible to apply the method for measuring the activity of the metal catalyst thin film as follows.

As the first method, TiO formed on the surface of the substrate₂An aqueous alkali halide solution such as potassium iodide or potassium chloride is dropped onto the surface of a photocatalyst thin film mainly composed of to determine the size of the activity of the photocatalytic thin film.

As a second method, TiO formed on the substrate surface₂On the surface of the photocatalyst thin film mainly composed of to determine the magnitude of the activity of

As a third method, TiO formed on the substrate surface₂The active-specific film is attached to the surface of the photocatalyst thin film mainly composed of, and in this state, the active-specific film is irradiated with ultraviolet rays for a predetermined time, and the activity of the photocatalyst thin film is measured with a change in the color of the active-specific film.

30 is a view for explaining the first and second activity specifying methods, and the surface of the substrate 1 is TiO₂A photocatalyst layer 2 mainly composed of

As the first method, TiO formed on the substrate surface₂An aqueous alkali halide solution such as potassium iodide or potassium chloride is dropped onto the surface of a photocatalyst thin film composed mainly of to determine the size of the activity of the photocatalytic thin film.

As a second method, TiO formed on the substrate surface₂A mixture solution containing a pH indicator added to an aqueous alkali halide solution such as potassium iodide or potassium chloride is added dropwise to the surface of a photocatalyst thin film mainly composed of to determine the magnitude of the activity of

As a third method, TiO formed on the substrate surface₂The active-specific film is attached to the surface of the photocatalyst thin film mainly composed of, and in this state, the active-specific film is irradiated with ultraviolet rays for a predetermined time, and the size of the activity of the photocatalyst thin film is determined by the change in the color of the active-specific film.

30 is a view for explaining the first and second activity specifying methods, and the surface of the substrate 1 is TiO₂A photocatalyst layer 2 mainly composed of After the dropwise addition, the added dropwise aqueous alkali solution 30 is irradiated with UV light for a predetermined time by means of an UV lamp 40, and the magnitude of the activity of the photocatalyst layer 2 from the difference between the pH of the aqueous solution of halogenated alkali before irradiation and the pH after irradiation. to judge

33 is a graph showing the relationship between the UV irradiation time and the change in pH, the concentration of the halogenated alkaline aqueous solution 30 is 0.1 mol/m, the UV lamp 4 is a BLB fluorescent lamp 20 W, and the photocatalyst layer 2 The distance between the ultraviolet lamp 4 and the ultraviolet lamp 4 was 20 cm, and the irradiation time was 60 minutes.

As can be seen from this figure, even in the photocatalyst layer 2 of any type of anatase type, metal-supported type, and rutile type, the pH of the aqueous alkali halide solution 30 is high until the irradiation time of ultraviolet rays is 30 minutes.

The reason that the pH of the aqueous alkali halide solution 30 becomes high by the irradiation of ultraviolet light as described above is that the following oxidation and reduction reactions occur simultaneously, and OH- (hydroxyl group ions) are generated by the reduction reaction.

Oxidation reaction: 2I^- + 2H⁺=I₂ + H₂

Reduction reaction: O₂ + H₂O + 4e^-=4OH^-

Therefore, when the pH of the aqueous alkali halide solution 30 becomes high by irradiation with ultraviolet rays, the photocatalyst layer 2 is said to have photoactivity.

34 shows R₃₀It is a graph showing the relationship between and pH change. where R₃₀is the ratio (%) of the gas (methyl mercaptan, etc.) decreased at 30 minutes after UV irradiation, and R₃₀It can be seen that there is a positive trade-off between and the amount of change in pH. That is, the amount of change in pH is an indicator of the presence or absence of photoactivity.

In the method 1 above, the amount of pH change is carried out by a pH meter or a pH measuring sheet 5, but in the second method, a mixed solution obtained by adding a pH indicator to an aqueous alkali halide solution 30 is dropped onto the surface of the photocatalyst layer 2, Then, ultraviolet rays are irradiated to the mixed solution dropwise for a predetermined time, and the size of the activity of the photocatalyst layer 2 is determined with a change in the color of the mixed solution.

As the pH indicator, methylet is suitable because the pH of the aqueous alkali halide solution 30 before irradiation with ultraviolet light is about 4.5 and the pH after irradiation with ultraviolet light is 5.5 to 6.5.

In addition, in the first method and the second method, a halogenated alkali aqueous solution 30 or a mixed solution obtained by adding a pH indicator to the halogenated alkali aqueous solution 30 is dropped on the surface of the photocatalyst layer 2, but the spread of the liquid dripped for each substrate Since they are each, a constant liquid thickness cannot be secured, and the reaction area is different for each substrate.

Solving this is a method shown in FIG. 31, and in this method, an alkali halogenated aqueous solution 30 is dropped on the surface of the photocatalyst layer 2, and then the halogenated alkali aqueous solution 30 is applied by a transparent plate 60 such as a glass plate. While pressing to a certain thickness, drying is prevented.

In addition, since the condition that the surface of the substrate 1 is horizontal for the liquid such as the aqueous alkali halide solution 30, it is difficult to determine the activity of the photocatalyst thin film formed on a vertical surface such as an already installed wall surface or a ceiling surface.

To solve this is the method shown in Fig. 32, and in this method, the activity measuring film 70 is attached to the surface of the photocatalyst layer 2 formed on the surface of the substrate 1, and in this state, the activity measuring film 70 is applied to the By irradiating ultraviolet rays and changing the color of the activity measuring film 70 , the size of the activity of the photocatalyst layer 2 is determined.

Here, the activity measuring film 70 is obtained by drying a mixed solution obtained by adding an aqueous solution of an alkali halide such as potassium iodide or potassium chloride and a pH indicator to an organic binder and molding the mixture into a film shape.

Next, the porosity of the photocatalyst layer 2 will be considered. Here, the porosity refers to an open porosity, and the porosity is 10% or more and less than 40%, and preferably 10% or more and 30% or less.

In this case, the crystal diameter of the photocatalyst particles may be less than 0.1 µm, preferably 0.04 µm. It is considered that the smaller the crystal grain size, the greater the reaction effective area per unit volume, and therefore the thickness of the photocatalyst layer is preferably about 0.1 mu m. In addition, when the layer strength is improved by solid-phase sintering the photocatalyst particles to form the neck portion, the crystal diameter increases to 0.1 μm or more and the effective reaction area per unit volume decreases, so the film thickness is 0.5 μm or more, preferably 0.6 μm or more.

In addition, between the photocatalyst particles constituting the photocatalyst layer formed on the surface of the substrate, particles having a crystal grain size of less than 0.01 µm, preferably 0.008 µm or less may be added. By adding such particles, the gap between the photocatalyst particles can be filled, the particle filling rate and the surface flatness can be improved, and thereby the film strength against shear stress can be improved. By improving the flatness of the surface, it is possible to make it difficult to adhere dirt. In this case, it results in a decrease in porosity, but the porosity buried therein is less than 0.01 μm in crystal thickness, preferably 0.008 μm or less, and is large compared to the size of gas (several Å), so it affects deodorization. does not affect

Here, the type of particles having a crystal diameter of less than 0.01 μm, preferably 0.008 μm or less, may be basically any, but in addition to filling the gaps between the photocatalytic particles, there is a possibility that some surfaces may be covered, so that the photocatalytic activity is not impaired. TiO₂, SnO, ZnO, SrTiO₃, Fe₂O₄, Bi₂O₃, WO₃ Oxide semiconductors, such as these, or metals, such as Ag and Cu, are preferable. In addition, a method of adding particles having a crystal diameter of less than 0.01 mu m, preferably 0.008 mu m or less, may be basically any method. For example, such ultrafine particles are generated by hydrothermal treatment or the like, and a sol dispersed in a suitable dispersion is applied on the photocatalyst layer by a spray coating method, and the organic dispersing agent may be evaporated by heat treatment at a low temperature such that particle growth does not occur. Alternatively, an alkoxide or an organometallic salt may be coated on the photocatalyst layer, heat-treated, and the diluent, organic component, and the like may be evaporated.

Further, metal particles smaller than the pore diameter of the photocatalyst layer formed on the surface of the substrate may be fixed. Since the metal particles are fixed, the photocatalytic activity is improved by the electron trapping effect compared to the case of the photocatalyst layer alone, and the deodorization property is better.

Here, the type of metal particles may be any material capable of capturing electrons. For example, Cu, Ag, Pt, etc. are mentioned.

The size of the metal particles needs to have an average particle diameter smaller than the average pore diameter on the surface of the photocatalyst layer. In addition, the average pore diameter of the surface of the photocatalyst layer is approximately the same as the photocatalyst particle diameter when observed with an electron microscope in a sample having a porosity of 10% or more and less than 40%, so it is required to be smaller than the photocatalyst particle diameter. Preferably, it is smaller than the photocatalyst particle diameter of the starting material. The starting material of the photocatalyst layer is preferably 0.05 µm or less because a raw material of 0.05 µm or less is generally used.

Hereinafter, specific examples regarding the porosity are given.

(Example 28)

TiO with a crystal diameter of 0.01 μm₂The ammonia peptizing suspension of the sol was applied to a 15 cm square tile substrate by varying the application amount by spray coating, and was fired at 700°C or higher and 900°C or lower to form a photocatalyst layer. Anatase TiO for the obtained sample₂ The crystal diameter of the particles, the open porosity of the layer surface, deodorization, abrasion resistance, and peeling resistance were evaluated.

R for deodorization₃₀(L) was evaluated by measuring. R₃₀(L) is the removal rate after light irradiation. Specifically, in an 11-liter glass container, the side on which the photocatalyst thin film is formed is placed at a distance of 8 cm from the light source (BLB fluorescent lamp 4W), and methyl mercaptan is added at an initial concentration of 3 ppm. It is obtained by injecting into a container and measuring the change in concentration when irradiated with light for 30 minutes.

Abrasion resistance was evaluated by performing perturbation abrasion using a plastic eraser, and comparing changes in appearance. The evaluation index is shown below in the same manner as in the previous period.

(double-circle) : No change with respect to 40 round-trips.

: A scratch occurs in the perturbation of more than 10 times and less than 40 times, and the photocatalyst layer (TiO₂membrane) is peeled

: The photocatalyst layer (TiO₂membrane) is peeled

×: A scratch occurs in the perturbation of less than 5 times, and the photocatalytic layer (TiO₂membrane) is peeled

The peel resistance test is a test in which the wear resistance test conditions are more stringent, and an eraser (LION TYPEWRITER ERASER 502) with a greater shear force was used instead of a plastic eraser. A specific evaluation method was performed by rubbing the sample surface with an equal force 20 times with an eraser, and observing and comparing the damaged state with the standard sample. Evaluation criteria are shown below.

: No change at all

: Check a slight change in light

: Slight change confirmed

× : Check changes at a glance

The results are shown in FIGS. 35 to 37 .

Fig. 35 shows the relationship between porosity, deodorization and abrasion resistance when the thickness of the photocatalyst thin film is 0.8 μm. The deodorizing property increases with the increase of the porosity and exceeds 50% in 10%, and reaches 80% or more in 30%. Conversely, the abrasion resistance was up to 30%, but at 40%, and or × when it exceeds this. From the above, in order to produce a member having both deodorizing properties and abrasion resistance, the porosity of the photocatalyst thin film needs to be 10% or more and less than 40 µm, preferably 10% or more and 30% or less.

Fig. 36 shows the film thickness dependence of the deodorizing properties when the crystal diameter of the photocatalyst particles constituting the photocatalyst thin film having a porosity of 20 to 30% is changed. R when the crystal diameter is 0.1 μm₃₀The film thickness dependence of (L) is seen, and when it becomes thin, deodorization property will fall. However, if film thickness dependence is not observed at 0.04 µm or less, good deodorizing properties are exhibited even at a film thickness of 0.1 µm. From the above, if the crystal diameter of the photocatalyst particles is less than 0.1 µm, preferably 0.4 µm or less, if the film thickness dependence is not observed, good deodorizing properties are exhibited even at a film thickness of 0.1 µm. From the above, it has been found that by making the crystal diameter of the photocatalyst particles less than 0.1 µm, preferably 0.4 µm or less, good deodorizing properties can be ensured even when the photocatalyst thin film is thinned to a film thickness of about 0.1 µm.

37 shows the film thickness dependence of deodorization and peeling resistance when the crystal diameter and bonding state of the photocatalyst particles constituting the photocatalyst thin film having a porosity of 20 to 30% are changed. The required value of the mechanical strength shows the peel resistance test film thickness dependence. When the required value of the mechanical strength was raised to the level of the peel resistance test, the sample without the neck portion became Δ or ×. In addition, in order to form a mechanically sufficient neck bond in solid-phase sintering between photocatalyst particles, the growth of photocatalyst particles was insufficient at 0.04 μm, and it was necessary to grow to about 0.1 μm. However, when the photocatalyst particles are grown to about 0.1 μm, the deodorization property has a film thickness dependence, and the thicker the film thickness, the higher the deodorization property. Specifically, at a film thickness of 0.5 μm, R₃₀(L) exceeds 50% and reaches 80% or more at 0.6 µm. From the above results, it is possible to sufficiently improve the strength of the thin film by solid-phase sintering the photocatalyst particles to form a neck portion between the particles and growing the particles until the particle diameter becomes 0.1 μm or more. In this case, the thickness of the thin film needs to be 0.5 µm or more, preferably 0.6 µm or more, because the effective reaction area per unit volume is reduced by increasing the crystal diameter to 0.1 µm or more.

(Example 29)

TiO with a crystal diameter of 0.01 μm₂The ammonia peptizing suspension of the sol was applied to a 15 cm square tile substrate by a spray coating method, and it was fired at 750° C. to form a photocatalyst thin film. TiO at this stage₂The porosity of the thin film is 45%, TiO₂ The crystal diameter of the particles was 0.02 µm. In addition, SnO with different crystal diameters₂Each of the species was applied by a spray coating method and dried at 110° C. to obtain a sample. Deodorization and abrasion resistance were evaluated about the obtained sample.

The results are shown in FIG. 38 . SnO for deodorization₂Even when the crystal diameter of the sol was changed from 0.0035 µm to 0.01 µm, there was little change, and good results were obtained. On the other hand, the abrasion resistance is effective when 30% by weight or more is added.₂It was different depending on the crystal diameter of the sol. That is, when particles of 0.08 μm or less were added, it was improved to or , but the effect of addition was not recognized at 0.01 μm.

From the above, it was found that the abrasion resistance was improved by adding particles having a crystal diameter of less than 0.01 µm, preferably 0.008 µm or less, between the photocatalyst particles.

(Example 30)

TiO with a crystal diameter of 0.01 μm₂The ammonia peptizing suspension of the sol was applied to a 15 cm square tile substrate with varying application amounts by spray coating, and this was baked at 850° C. to form a photocatalyst thin film with a film thickness of 0.2 μm. Then, an aqueous solution of copper acetate was applied to the photocatalyst thin film by spray coating, and then photoreduction (the light source was a 20-watt BLB lamp, the distance from the light source to the sample was 10 cm, the irradiation time was 10 seconds) to obtain a sample. At this time, the amount of supported copper was 2 μg/cm 2 , and the particle size thereof was several nm to 10 nm. In addition, the crystal diameter of the photocatalyst particles was 0.1 μm. Deodorization and abrasion resistance were evaluated about the obtained sample.

As a result R₃₀(L) was 89% and abrasion resistance was (double-circle). Therefore, compared with FIG. 36, R by supporting copper₃₀(L) dramatically improved from 18% to 89%.

From the above description, it is possible to provide a member having both deodorizing properties and abrasion resistance by forming a photocatalyst thin film having a porosity of 10% or more and less than 40%, preferably 10% or more and 30% or less, on the surface of the substrate.

Next, an embodiment in which the gaps formed in the photocatalyst layer are filled with particles smaller than the gaps will be described. The gap in this embodiment refers to both the gap between the separated particles and the main part of the neck part.

In addition, the denser the photocatalyst layer is superior in film strength and difficulty in adhering dirt. In general, the temperature at which the photocatalyst layer is formed becomes high and the material of the substrate is limited. The porosity of the photocatalyst layer before the addition of interstitial particles according to the present application may be 10% or more. In addition, since the membrane having a porosity of 10% or more has excellent deodorization properties, by adjusting the filling amount, it is possible to provide a multifunctional material excellent in both antifouling properties and deodorization properties.

The particles smaller than the gaps filled in the gaps are preferably made of an inorganic crystalline material, and more preferably TiO from those having photocatalytic activity.₂, SnO₂, ZnO, SrTiO₃, Fe₂O₃, Bi₂O₃, WO₃of oxide semiconductors are good.

The size of the particles smaller than the gap should be smaller than the average value of the pore diameters to be created. Specifically, it is less than 0.01 μm in terms of improving surface flatness by reducing gaps and reducing particles adhering to the surface of particles having a photocatalytic function, and improving the adhesion of dirt and film strength by reducing surface defects. , preferably small particles of 0.08 μm or less. However, TiO₂ When the thin film is fixed on the substrate by heat treatment at 850°C or lower with anatase, when observed with an electron microscope, the average pore diameter and TiO₂ TiO from the same particle size₂ It is better if it is smaller than the particle size. TiO with photocatalytic activity₂ Since the starting material of the thin film is generally less than 0.05 µm, it is preferable that it be less than 0.05 µm.

Here, by setting the porosity of the surface of the layer having a photocatalytic function in which particles are filled in the gaps to be less than 20%, it becomes more difficult to attach dirt. In addition, it is preferable that the maximum width of the open pores be 0.04 µm or less.

Here, the porosity refers to the open porosity of the surface of the substrate, and the maximum width of the open pores is the maximum value (average value + 3 × standard deviation) of the treatment of the spacing between two adjacent particles among the particles having a photocatalytic function constituting the surface of the substrate.

In addition, the porosity of the layer having a photocatalytic function for filling particles in the gap is reduced to less than 10% if a porosity of about 10% is used, but the pore diameter buried here is the size in which particles with a crystal diameter of less than 0.01 μm enter, Because it is large compared to the size of the gas (several Å), it does not affect the deodorizing property, and the pre-fabricated pores are reduced by 10% or more of TiO.₂ It is possible to maintain deodorizing properties equivalent to that of a thin film.

In addition, since the formed layer having a photocatalytic function is mainly used as crystalline photocatalyst particles, scale does not adhere to the glass in a strong adhesion form, and at the same time, it blows off relatively easily even if attached, for example. In addition, when used for water circulation, there is an effect that moss is difficult to form.

Here, when the crystalline photocatalytic particle is powder X-ray diffraction of the photocatalyst particle separated from the member under 50 kV-300 mA condition, the maximum peak of the crystal (for example, TiO₂ As for the particles, 2θ = 25.3° for anatase and 2θ = 27.4° for rutile) are crystallized photocatalyst particles.

As a method of filling the gap with particles, it is formed by coating, drying, and heat treatment using a metal alkoxide, an organometallic salt, a sulfate, or the like. For example, in the step of using a metal alkoxide, a solution in which a metal alkoxide is mixed with a suitable diluent and hydrochloric acid is applied to the outermost surface of the photocatalyst layer, followed by drying and heat treatment. Here, the suitable diluent is preferably an alcohol such as ethanol, propanol, or methanol, but is not limited thereto. However, it is better not to contain water as much as possible. This is because, when water is contained, hydrolysis of the metal alkoxide is accelerated explosively, which is one cause of the occurrence of cracks.

In addition, the addition of hydrochloric acid is to prevent cracks from occurring during drying or heat treatment. The coating method of the metal alkoxide is usually performed by flow coating, but is not limited thereto. The flow coating is preferably performed in dry air. When coating is carried out in normal air (atmosphere), hydrolysis is accelerated by moisture in the air, making it difficult to control the film thickness. The coating may be applied once or may be applied several times. This is determined by the filling properties of the photocatalyst layer before application. After that, when it is left for moisture in dry air, a film filled with particles is formed in the gaps between the photocatalyst layers.

Here, when the layer before application of the charged particles and the charged particles are made of the same material, the coefficient of thermal expansion is the same, which is preferable in terms of forming a film having excellent mechanical strength.

Moreover, the thing using Ti alkoxide as a specific example is further demonstrated. In the step of applying the Ti alkoxide to the surface of the photocatalyst layer again and performing a dry heat treatment, the amount of Ti alkoxide applied per one time is TiO₂In terms of , it was set to be 10 μg/cm 2 or more and 100 μg/cm 2 or less. If the amount is too small, it is not efficient because the number of times of application must be increased. Conversely, if the amount is too large, the film thickness per application becomes too thick, and cracks occur during drying and heat treatment.

In the dry heat treatment step, the heat treatment temperature was 400 °C or higher and 800 °C or lower. Below 400 °C, amorphous TiO₂is anatase-type TiO₂It does not crystallize at a temperature of 800°C or higher, and rapid grain growth occurs and the photoactivity decreases. In addition, the amount of hydrochloric acid with respect to the Ti alkoxide in the coating liquid was set to be 1 wt% or more and 10 wt% or less. If it is less than 1% by weight, the crack prevention effect is not sufficient, and if it exceeds 10% by weight, hydrochloric acid is usually a 36% aqueous solution, so a large amount of water enters and hydrolysis is excessively accelerated to generate cracks. When the amount of hydrochloric acid is large, it is better to use a large amount of diluent. This is because the diluent inhibits hydrolysis. Its ratio is hydrochloric acid (water agent): diluent 1:100 to 1:1000 is good.

In addition, at least one of Cu, Ag, Zn, Fe, Co, Ni, Pd, and Pt is formed on the layer in which a layer having a photocatalytic function is formed, and particles smaller than the gap are filled in the gaps generated on the surface of the layer. The metal of the bell may be fixed. With this configuration, since the metal occupies the highly adsorbable sheet of the layer having a photocatalytic function in advance, the photocatalytic activity is not lost due to the adhesion of alkali metals, calcium, etc. in the dust component to that part. Therefore, the antibacterial action by the photocatalyst is not impaired, and contamination by the attachment of fungi is also prevented. In addition, when Ag, Cu, and Zn are used as metals, since these metals themselves have antibacterial properties, contamination due to adhesion of fungi is effectively prevented. In addition, the photoactivity of the photocatalyst layer is improved by the electron trapping effect of these metals.

The size of the fixed metal is large enough to occupy a site with high adsorption properties of the photocatalyst layer in advance, and the smaller one is narrow enough to maintain high activity. From such a viewpoint, about several nm to 10 nm is preferable.

Here, as a method for fixing the above metal, a photoreduction method, a heat treatment method, a sputtering method, a CVD method, etc. may be used, but the photoreduction method does not require large-scale equipment, is a relatively simple method, and can be firmly fixed. This is preferable. The process using photoreduction is performed by applying an aqueous solution containing at least one metal ion among Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt, and irradiating light containing ultraviolet rays. The aqueous solution containing at least one metal ion selected from Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt includes copper acetate, silver nitrate, copper carbonate, copper sulfate, cuprous chloride, zinc nitrate, cobalt chloride, and a chloride agent. Ferrous iron, ferric chloride, etc. are mentioned. The coating method of the aqueous metal salt solution may be basically any method, but the spray coating method or the dip coating method is simple. Comparing these two, the spray coating method is more preferred due to the fact that the amount of solution to be used can be reduced, that it can be applied uniformly, that the film thickness is easy to control, and that it is possible to prevent adhesion to the back surface. desirable. The light source for irradiating light containing ultraviolet light may be any light source capable of irradiating light containing ultraviolet light, and specifically, any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, and a fluorescent lamp may be used. In the method of irradiating light containing ultraviolet rays, it is preferable to arrange the sample so that the light hits the irradiation surface perpendicularly. This is because the research rate is the best. The irradiation time is preferably about 10 seconds to 10 minutes. If the irradiation time is too short, the metal does not sufficiently adhere to the site with high adsorption properties of the photocatalyst layer, so alkali metal, calcium, etc. in the dust component adhere to cause loss of photocatalytic activity. This is because it is difficult for light to reach the photocatalytic layer sufficiently, thereby reducing the photocatalytic activity. The distance from the light source of the sample is preferably 1 cm to 3 cm. If the distance is too short, the light is not irradiated with uniform illuminance on the entire surface of the sample, and non-uniformity occurs in the adhesion of the metal species. It is difficult to attach firmly.

Hereinafter, specific examples of filling the gaps formed in the photocatalyst layer with particles smaller than the gaps will be given.

(Example 31)

TiO with a crystal diameter of 0.01 μm₂ Ammonia peptizing suspension of sol is applied on a 15 cm square tile substrate by spray coating, and it is calcined at 750° C. to form anatase-type TiO₂ A thin film was formed. TiO at this stage₂ The porosity of the thin film is 45%, TiO₂ The crystal diameter of the particles was 0.02 µm. Next, SnO with different crystal diameters₂Each of the sols was applied by a spray coating method and dried at 110° C. to obtain a sample. The obtained samples were evaluated for deodorization, abrasion resistance, and difficulty in attaching dirt.

R for deodorization₃₀(L) was measured and evaluated.

Abrasion resistance was evaluated by performing perturbation friction using a plastic eraser, and comparing changes in appearance. An evaluation index is shown below.

(double-circle) : No change with respect to 40 round-trips.

: Scratches occur in perturbations of 10 or more and less than 40 times, TiO₂layer peeled

: Scratches occur in perturbations of 5 or more times but less than 10 times, TiO₂layer peeled

×: Scratches occur in less than 5 perturbations, TiO₂layer peeled

To evaluate the difficulty of contamination adhesion, a line was drawn on the surface of the substrate with black thick magic ink, and the contamination state was evaluated after drying and wiping the ink with ethanol.

: Completely erased traces

: Slight traces remain

: traces of blue gray remain

×: black traces remain

The results are shown in FIGS. 39 to 46 .

39 is SnO₂It shows the difficulty of attaching the contamination to the added amount. where SnO₂The addition amount of TiO₂with SnO₂ SnO for the sum of the positive weights₂ It is expressed as a weight ratio. More than 30% SnO₂ In addition, contamination becomes difficult to adhere dramatically. The reason is interpreted as the following three. First, SnO₂This is because the porosity is reduced to less than 20% by adding 30% or more of the (FIG. 40). Second, SnO₂This is because pores with large porosity are reduced by the addition of 41 is SnO₂Although the maximum width of open pores is shown with respect to the amount of added SnO2, it is considerably small at 0.04 μm when the amount of SnO2 added is 30% or more. Third, SnO₂It is also interpreted that the improvement of surface roughness by the addition of

42 is SnO₂It shows the deodorizing properties and abrasion resistance for the added amount.

SnO for deodorization₂Even when the sol changes the crystal diameter from 0.0035 µm to 0.01 µm, there is almost no change, and good results are obtained. Also SnO₂For the amount of R, if less than 50%₃₀A favorable result was shown with this 80% or more. Figure 39 SnO₂Comparing the relationship between the addition amount of SnO and the porosity₂In the addition amount of 40% or more and 50% or less, the porosity was less than 10%, and the deodorization property was good. This tendency is a result different from the relationship between the porosity and the deodorizing property (FIG. 35) in the case where the particle|grains which fill a gap are not added. The reason is considered as follows. That is, in this case, the porosity is decreased to less than 10%, but pores of about 0.02 μm remain from FIG. This is because, under this condition where there is no growth of

As for wear resistance, SnO₂ The effect when the addition amount is 30% or more is SnO₂It depends on the crystal diameter of the sol. That is, when particles of 0.008 μm or less were added, it was improved to or , but the effect of addition was not recognized at 0.01 μm.

Through the above experiment, the following facts were found.

(1) TiO in the substrate₂ After forming a film, in the gap created on the surface of the thin film, particles smaller than the gap (SnO₂sol), it is difficult for contamination to adhere.

(2) SnO₂of TiO₂with SnO₂If it is more than 30% by weight based on the total weight of the contamination, it is difficult to adhere and the abrasion resistance is also improved.

(3) SnO₂of TiO₂with SnO₂If it is less than 50% by weight based on the total weight of the deodorizing property is maintained well.

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

(Example 32)

Anatase TiO on the side of the urinal's base that does not reach the light₂ A film-formed product was installed, and a field test was conducted for 2 weeks, followed by normal anatase-type TiO₂ compared to that which did not form a film. As a result, yellow due to the fungus and urine stone adhered to both. However, while the contamination does not come off to the extent of rubbing in the base of a normal toilet bowl, anatase-type TiO in the side part₂ When the film was rubbed, the stain yellow was almost invisible.

Since the side of the support is not irradiated with light, this result is anatase-type TiO₂ It is interpreted that this is because the film was formed on the surface.

(Example 33)

SiO on the surface of 15 cm square ceramic tile₂-Al₂O₃-Na/K₂After coating on the O frit, TiO with a crystal diameter of 0.01 μm on the surface₂Ammonia peptizing suspension of sol is applied by spray coating method, calcined at 750°C for 2 hours, and TiO₂ Three types of 0.2 µm, 0.4 µm, and 0.8 µm were made from the film thickness of the thin film. TiO at this stage₂ The porosity of the thin film is 45%, TiO₂ The grain size was 0.02 μm. Again, a 10:1:400 (weight ratio) mixed solution of titanate tetraethoxide, 36% hydrochloric acid and ethanol was applied to the cooled sample by flow coating using dry air as a carrier, followed by drying. Application amount is TiO₂was set to 40-50 μg/cm 2 . Then, it was baked at 500 degreeC for 10 minutes. This Ti alkoxide application process was repeated 1 to 5 times. The obtained samples were evaluated for deodorization properties, antibacterial properties, abrasion resistance, and difficulty in adhesion of stains.

The antibacterial properties were tested using Escherichia coli strain W3110. 0.15 ml (1-50000 CFU) of the bacterial solution was dripped onto the outermost surface of the multifunctional material previously sterilized with 70% ethanol, placed on a glass plate (100×100 mm), and brought into close contact with the outermost surface of the substrate to obtain a material. After irradiating a white light (3500 lux) for 30 minutes, wash the bacterial solution of the irradiated sample with a sterile gauze, recover with 10 ml of physiological saline, calculate the survival rate of bacteria, and evaluate the +++, ++, +, - Same as above.

In any of the above conditions, the deodorization is R₃₀In (L), the antibacterial property of 80% or more was +++.

For antifouling (FIG. 43) and abrasion resistance (FIG. 44), the number of times of Ti alkoxide application and TiO₂ Depends on the film thickness. That is, if the number of times of Ti alkoxide application is increased, antifouling and abrasion resistance are improved. Also, TiO₂ As the film thickness became thinner, antifouling and abrasion resistance were improved at a small number of Ti alkoxide applications. Also, TiO₂ As the film thickness became thinner, antifouling and abrasion resistance were improved at a small number of times of Ti alkoxide application. As one of the reasons for the above, TiO by Ti alkoxide coating₂A reduction in the porosity of the layer surface is considered. TiO in Figure 45₂The porosity of the layer surface and the number of Ti alkoxide coatings and TiO₂ It shows the relationship of the film thickness. TiO₂It decreases as the number of times of Ti alkoxide application on the layer surface increases, and also TiO₂ As the film thickness decreases, the number of times of Ti alkoxide coating is decreasing, and this relationship is related to the number of times of Ti alkoxide coating and TiO.₂ In terms of film thickness and antifouling properties, as in Example 31, when the porosity was less than 20%, all of them were (double-circle).

(Example 34)

SiO on the surface of a 15 cm square ceramic tile₂-Al₂O₃-Na/K₂O frit is applied, and then TiO having a crystal diameter of 0.01 μm is applied to the surface.₂ An ammonia peptizing suspension of the sol was applied by a spray coating method and calcined at 750°C for 2 hours. TiO at this stage₂ The film thickness of the thin film is 0.4μm, the porosity is 45%, TiO₂The crystal diameter of the particles was 0.02 µm. A mixed solution of titanate tetraethoxide, 36% hydrochloric acid, ethanol, and 10:1:400 (weight ratio) was applied to the cooled sample again by flow coating using dry air as a carrier, followed by drying. Application amount is TiO₂at 40-50 μg/cm 2 . Then, it baked at 500 degreeC for 10 minutes. This Ti alkoxide application process was repeated 3 times. After that, 1 wt% of silver nitrate aqueous solution was applied on the sample again, and light reduction (light source was 20 watts, BLB lamp, distance from light source to sample 10 cm, irradiation time 30 seconds) to obtain a sample. Here, the amount of silver supported on the sample surface was 0.7 μg/cm 2 , and the average silver particle size was about 40 nm. The obtained samples were measured for antibacterial properties and antibacterial properties after long-term use.

The antibacterial properties after long-term use were tested as follows. First, the surface of the obtained sample was washed well with ethanol or the like, and dried at 50°C. Next, bath water collected from a public bath was put into a sterilized beaker, and the sample was immersed in it and left for one month.

Thereafter, a sample was collected, washed with ethanol or the like, and the outermost surface of the multifunctional material was sterilized with 70% ethanol. Subsequently, 0.15 ml (1-50000 CFU) of Escherichia coli strain W3110 was placed on a glass plate (100×100 mm) and adhered to the outermost surface of the substrate to obtain a sample. After irradiating a white light (3500 lux) for 30 minutes, the bacterial solution of the irradiated sample was wiped with sterile gauze, recovered with 10 ml of physiological saline, and the survival rate of the bacteria was obtained as an evaluation index. The evaluation index is the same as the antimicrobial test of Example 3.

The sample used in Comparative High Example 33 was also tested.

As a result, the initial antibacterial property was +++ in both the sample prepared in this example and the sample prepared in Example 33, but there was a difference between the two in the antibacterial property after 1 month. That is, in the sample prepared in Example 33, the antibacterial property deteriorated to +, but in the sample prepared in this Example, it was +++, showing a value unchanged from the initial value. This is TiO₂ It is thought that this is because silver occupies a site with high adsorption on the surface, preventing dust or the like from adhering to a site with high adsorption during use.

From the above description, since a layer having a photocatalytic function is formed on the surface of the substrate, and particles smaller than the gaps are filled in the gaps created on the surface of the gaps, the amount and size of gaps present on the surface are smaller than that of the conventional photocatalytic thin film. , and since the surface flatness is improved, the film strength is improved while maintaining deodorization and antibacterial properties, and it is difficult for polymers, dust fungi, etc. constituting the contaminant components to adhere.

Next, the case where a material with a low melting point, such as soda glass, is used as a base material is demonstrated. That is, in the case of forming a photocatalyst thin film on the surface of a low melting point substrate, softening already begins at this photocatalyst thin film formation temperature, and the formed photocatalyst thin film is buried in the substrate, so that light does not reach the photocatalyst layer, so that the photocatalytic function can be exhibited. There is no disadvantage.

Here, in this case, SiO₂ The photocatalyst particles are fixed to the substrate through a layer having a high melting point from the substrate such as a coating. Examples are specifically described below.

(Example 35)

Before coating the soda glass with titanium oxide, silica was coated on the surface of the soda glass.

Silica coating was performed on 22 sides of a 10 cm square soda glass by the following method. First, tetraethoxysilane, 36% hydrochloric acid, pure water, and ethanol are mixed in a ratio of 6: 2: 6: 86 (weight ratio). Since it generates heat at this time, it is left to stand for about 1 hour. These soda glasses were flow-coated.

Next, a coating solution is prepared. The coating solution was prepared by adding 10% by weight of titanate tetraethoxide and ethanol to a mixture of 1:9 (weight ratio) and 36% hydrochloric acid based on titanate tetraethoxide. The amount of 36% hydrochloric acid added thereto is preferably 1 wt% or more and 30 wt% or less, preferably 5 wt% or more and 20 wt% or less, based on titanate tetraethoxide. By adding an appropriate amount of hydrochloric acid, it is possible to prevent cracks from entering during drying and firing in the post-process. That is, if the amount of hydrochloric acid is too small, crack prevention cannot be sufficiently achieved, and if the amount of hydrochloric acid is too large, the hydrolysis of tertanate tetraethoxide is accelerated by increasing the amount of water contained in the hydrochloric acid reagent, making a homogeneous coating difficult will do

Next, this solution is flow-coated on the surface of the soda glass substrate in dry air. Here, dry air does not mean air containing no moisture at all, but refers to air having less moisture than normal air. At this time, if coating is performed in normal air without drying treatment, hydrolysis of titanate tetraethoxide is accelerated in the moisture in the air, so that the amount of coating film applied at one time becomes too large, and cracks occur during drying and firing in the subsequent step. easy. In addition, as the hydrolysis is accelerated, it becomes difficult to control the amount of the coating film. In order to prevent cracks, it is preferable that the amount of titanium oxide supported at one time is 100 μg/cm 2 or less. This time, the loading amount of titanium oxide at one time was 45 µg/cm 2 .

Thereafter, titanium oxide powder is formed by drying in dry air for 1 to 10 minutes. In order to obtain titanium oxide in the process so far, it is based on the principle shown below. Here, the starting raw material is titanate tetraethoxide, which is one type of titanium alkoxide (in principle, the same can occur even if other titanium alkoxides are used). This titanate tetraethoxide is mainly used, and during flow coating, it hydrolyzes with water in dry air to produce titanium hydroxide. Moreover, a dehydration condensation reaction occurs during drying, and amorphous titanium oxide is formed on the substrate. The titanium oxide particles produced at this time have a high purity of about 3 to 150 nm. For this reason, this titanium oxide has the characteristic of sintering at low temperature compared with the titanium oxide obtained by other methods.

The composite member obtained by the above method is again fired at 300°C to 500°C to obtain a multifunctional material. If necessary, the process from the coating film of titanate tetraethoxide to firing was repeated to apply a thick layer of titanium oxide.

The samples thus obtained were evaluated for deodorization properties, abrasion resistance properties, and antibacterial properties. The results are shown in (Table 19).

[Table 19]

<img file="KR100357482B1_D0019.tif" />

Regarding the deodorizing properties, the methylmercaptan removal rate after 30 minutes when the sample was placed in a cylindrical container with a diameter of 26cm x height of 21cm and a 4W BLB fluorescent lamp was irradiated with light 8cm away from the sample, the initial concentration of methylmercaptan was adjusted to 2ppm ( R₃₀(L)) and the methylmercaptan removal rate (R) after 30 minutes when light is shielded₃₀(L)) was measured and evaluated.

For the abrasion resistance, perturbation abrasion using a plastic eraser was performed, and the change in appearance was evaluated by comparison. At this time, the evaluation indicators , , , and × are the same as described above.

For the antibacterial properties, Escherichia coli W3110 strain was used to test. 0.15 ml (1-50000 CFU) of the bacterial solution was dripped onto the outermost surface of the multifunctional material previously sterilized with 70% ethanol, placed on a glass plate (100×100), and adhered to the outermost surface of the substrate to obtain a sample. After irradiating a white light (5200 lux) for 30 minutes, the bacterial solution of the irradiated sample and the bacterial solution of the sample maintained under light-shielding conditions were wiped with sterile gauze, recovered with 10 ml of physiological saline, and the survival rate of the bacteria was obtained as an evaluation index. Evaluation indices +++, ++, +, - are the same as described above.

At the firing temperature of 300°C, good results are shown as in the perturbation test, but R₃₀(L) was 0%. This is thought to be due to not being crystallized with anatase from amorphous titanium oxide.

At 400°C, where anatase can be identified by X-rays in the synthesis experiment, the perturbation test also shows good results as , but R₃₀(L) also improved to about 60%. In addition, the antibacterial property also became +. Also, the perturbation test shows good results as even at 500°C, but R₃₀(L) also improved to about 60%.

Furthermore, when the temperature was increased, the soda glass of the substrate was changed at 550° C., and a multifunctional material was not manufactured.

(Example 36)

In order to further improve the photocatalytic properties of the sample obtained in Example 35, metal particles were supported. A photocatalyst performs a reduction reaction simultaneously with an oxidation reaction. If the reduction reaction does not proceed, electrons are not consumed and the particles are equal and the oxidation reaction does not proceed. R in Example 1₃₀The reason (L) stayed at 60% is thought to be the cause. In order to prevent this, it is good to support the metal particles on the titanium oxide particles, and to drive away electrons to prevent charging.

The metal particles were supported by the following method. A solution of a metal salt was flow-coated on a photocatalyst, and a BLB fluorescent lamp 20W was irradiated at a distance of 20 cm for 1 minute. For the metal salt solution, a 1 wt% methanol solution of copper acetate was used in the case of copper supporting, and a 1 wt% ethanol/water = 1/1 mixed solution of silver nitrate was used in the case of silver. After irradiation, it was washed and dried. Here, when a solution containing ethanol is used without using an aqueous metal salt solution, the wettability of the metal salt solution to the sample is good.

The samples thus obtained were evaluated for deodorization properties, abrasion resistance properties, and antibacterial properties. The results are shown in (Table 20). In addition, only the sample obtained at 500 degreeC was used for the calcination temperature.

[Table 20]

<img file="KR100357482B1_D0020.tif" />

In the perturbation test, a good result was indicated by a double mark. Also R₃₀(L) improved dramatically to 98%. The antibacterial property also became +++.

(Comparative Example 37)

In Example 35, the same was applied to those not subjected to silica coating. That is, a 10 cm square soda glass was coated with titanium oxide. The results are shown in (Table 21).

[Table 21]

<img file="KR100357482B1_D0021.tif" />

From (Table 21), 300 °C, 400 °C, 500 °C all showed good results in the perturbation test as , but R₃₀(L) was 0% even if the process was repeated 10 times from the coating film of titanate tetraethoxide to calcination. In addition, the antibacterial properties were all -.

R at 300°C₃₀(L) is considered to be bad because titanium oxide has not yet been crystallized with anatase from amorphous titanium oxide.

On the other hand, at 400°C and 500°C, amorphous titanium oxide is already crystallized with anatase, and for the above reason, R₃₀(L) Can't explain this bad thing. The cause is thought to be that the titanium oxide film is buried in the glass because the soda glass, which is the base material, softens.

From the above description, it has become possible to produce a multifunctional material having deodorizing properties and antibacterial properties by interposing a high melting point layer between the photocatalyst layer and a substrate having a relatively low melting point.

Next, a preferred embodiment for imparting a photocatalytic effect to a surface of a plastic or the like having poor heat resistance will be described.

The material of the base material is not limited to plastic with poor heat resistance, and basically any material such as ceramics, ceramics, metal, glass, or a composite thereof may be used.

The shape of the base material may be any, and even in simple shapes such as spherical, columnar, cylindrical, or plate-like materials such as tiles, wall materials, and flooring materials, complex shapes such as sanitary ware, washbasin, bathtub, sink, and toilet seat can be used. no matter what Further, the substrate surface may be porous.

The binder may be a thermoplastic material such as inorganic glass material, a thermoplastic resin, or solder, or a thermosetting material such as a fluororesin, a siloxane resin, or a silylone resin. However, it is preferable that the material is light corrosion-resistant by irradiating light containing ultraviolet rays in post-fixing. In addition, since the usefulness of this application is particularly high when only heat treatment at 300°C or lower can be performed, it is preferable that a material that can be softened at 300°C or lower for a thermoplastic material and a material that can be cured at 300°C or lower for a thermosetting material is particularly high. desirable. Examples of the material satisfying these conditions include dispersion-based glass, solder, and acrylic resin in the case of thermoplastic materials, and fluororesin, siloxane resin, and silicone resin as thermosetting materials.

As a method of applying these binder layers on the substrate, when a thermoplastic material is used, a spray coating method, a roll coating method, a deep coating method, etc. may be mentioned. good. In addition, the binder component does not necessarily have to match the binder composition when the member is completed. For example, when the binder is made of inorganic glass, the coating material may be a suspension of an inorganic glass composition such as granular, frit, bulk, or powder, or a mixture of salts containing subsequent metal components. When the binder is a resin, a solution of the resin having the composition may be used, or a method other than that may be used.

Before applying the photocatalyst particles on the binder layer, the applied binder layer may be dried and moisture or the like may be evaporated. The drying method at this time includes a method by standing at room temperature, a method of heating together with the substrate, and the like.

In addition, the binder layer applied before the application of the photocatalyst particles other than the binder layer may be lower than the softening temperature of the substrate, and the binder composition may be changed to a temperature at which the binder layer is softened when the member of the binder layer is completed. According to this method, when the photocatalyst particles are formed on the binder layer, a sufficient effect can be exhibited even in a small amount of the photocatalyst particles applied in advance so that the binder layer becomes more flat.

When a thermosetting material is used, the method of applying the binder to the substrate by mixing the curing agent is carried out by, for example, adding a diluent to the thermosetting resin and then applying the mixture obtained by adding the curing agent to the surface of the substrate.

The thickening viscosity is preferably 105 poisc or more and less than 1075 poise. By setting the viscosity to be higher than 105 poise, the photocatalyst particles are applied so that the photocatalyst particles are not completely buried in the binder layer, so that the burial is possible. because it makes it possible.

The method of applying the photocatalyst particles to the surface of the binder layer is basically carried out by applying an appropriate treatment to the starting material on the binder layer.

As a starting material, a sol suspension of a photocatalyst composition is preferable, but a suspension of fine particles of a photocatalyst composition may also be used. In any case, in order to achieve a uniform coating, it is necessary to add a surface treatment agent such as an improving agent to prevent the photocatalyst composition from aggregating in the suspension. The application to the binder layer includes a spray coating method, a roll coating method, a dip coating method, etc., but any of them may be used, and other methods may be used.

It is preferable that the photocatalyst layer is embedded as a binder layer with a thickness of at least 1/4 of the thickness of the photocatalyst in view of bonding strength with the substrate. The thickness of the photocatalyst layer is obtained by analyzing the elements constituting the photocatalyst particles in the cross-sectional direction by EBMA, etc., and the amount of the constituent elements constituting the photocatalyst particles is almost constant in the upper layer and the depth at which the amount of constituent elements constituting the photocatalyst particles begins to decrease It becomes a buried part between the depth at which the amount of component elements constituting the binder starts to become constant.

The surface treatment agent attached to the photocatalyst is mainly a component added to disperse the sol of the starting material of the photocatalyst particles. Specific examples include pentaerythritol, trimethylolpropane, triethanolamine, trimethylolamine, silicone resin, and alkylchlorosilane.

Examples of light sources of light containing 1.7 mW/cm 2 or more of light having a wavelength of 390 nm or less include BLB fluorescent lamps, ultraviolet lamps, sterilizing lamps, xenon lamps, mercury lamps, and the like. The reason why light having a wavelength of 390 nm or less must be 1.7 mW/cm 2 or more is that dispersant components such as silicone resins have a certain degree of light corrosion resistance and do not decompose unless the intensity of ultraviolet light is of this level. At this time, the shorter the wavelength of ultraviolet rays, the faster the dispersing agent decomposes, but depending on the type of binder, there is a risk of decomposition of the binder, and it is also harmful to the human body. For this reason, 250 nm is preferable. In addition, the decomposition rate is fast with the increase of the illuminance up to the illuminance of about 3 mW/cm 2 , but above that, even if the illuminance is increased, it does not contribute much to the improvement of the decomposition rate, so 3 mW/cm 2 or less is sufficient.

The above process is schematically shown in FIG. A photocatalyst layer 2 is formed on the substrate 1 with a binder layer 6 interposed therebetween by embedding a part of the lower layer in the binder layer 6 . Reference numeral 6a denotes a layer made of a surface treatment agent or the like that inhibits photocatalytic activity. UV represents light containing 1.7 mW/cm 2 of light having a wavelength of 390 nm or less.

Next, a description will be given of a case in which a layer of mainly photocatalyst particles 3 and a thermosetting resin 6 is formed on the surface of the substrate, irradiated with ultraviolet rays in the same manner, and the photocatalyst layer is exposed (refer to FIG. 4). Even in this method, the photocatalyst particles 3 are firmly fixed to the substrate by the thermosetting resin, and by irradiating light containing 1.7 mW/cm2 of light with a wavelength of 390 nm or less, the photocatalytic reaction occurs in the light irradiation part of the surface of the photocatalyst particles. Since the thermosetting resin is preferentially decomposed and vaporized in the direction of the surface treatment agent and the light source, and the photocatalyst particles are exposed to the outside, sufficient photocatalytic activity can be obtained.

In addition, in the method of forming a layer mainly composed of photocatalyst particles and thermosetting resin, for example, a mixture obtained by adding a well-dispersed photocatalyst to a suspension in order of a thermosetting resin, a diluent, and a curing agent is applied to the surface of the substrate, followed by heat treatment to form. .

Here, the sol in the photocatalyst suspension has a crystal diameter of 0.05 µm or less, more preferably 0.01 µm or less. This is because the smaller the crystal diameter, the higher the photocatalytic activity. In addition, it is preferable that the sol such as the photocatalyst layer suspension is as monodispersed as possible. This is because the better the dispersibility, the more uniform the coating film is.

It is preferable that the thermosetting resin used here has light corrosion resistance to white light or normal fluorescent lamp level light. It is because this side is excellent in durability at the time of use. In that sense, siloxane resins and fluororesins are particularly preferable.

The diluent is added because it reduces the formation of a mixture of the photocatalyst sol and the thermosetting resin and makes it easy to apply the mixture to the surface of the substrate. Therefore, the diluent used herein may be basically any solvent as long as it can achieve its purpose. For example, water, ethanol, propanol, and the like may be used.

A method of applying the mixed solution to the substrate includes a spray coating method, a roll coating method, a dip coating method, a spin coating method, etc., but any of them may be used or other methods may be used. It is common to use an electric furnace, a gas furnace, a vacuum furnace, a pressurization furnace, etc. as a heat treatment furnace, but is not limited thereto. A layer mainly composed of photocatalyst particles and a thermosetting resin may be formed on the surface of the substrate with a thermosetting resin layer or a photocurable resin layer (intermediate layer: C) interposed therebetween (see Fig. 48).

According to this method, an extremely flat surface can be formed before the photocatalyst layer is applied by the thermosetting resin layer or the photocurable resin layer disposed in the middle of the substrate and the photocatalyst layer even if there are irregularities in the substrate, so that the photocatalyst layer can be easily formed can be formed In addition, since bonding to the substrate can be sufficiently achieved by the thermosetting resin layer or the photocurable resin layer disposed in the middle of the substrate and the photocatalyst layer, even if there are irregularities on the surface of the substrate, the layer made of the photocatalyst particles and the thermosetting resin is thinly Since the photocatalytic particles can be concentrated in the vicinity of the surface of the substrate at the same time as can be formed, the subsequent step of irradiating light containing 1.7 mW/cm 2 or more of light having a wavelength of 390 nm or less can be completed in a short time. In addition, since there is a layer made of photocatalyst particles and thermosetting resin on the upper surface, ultraviolet rays with sufficient strength due to decomposition and vaporization during use in the post process do not reach the thermosetting resin or photocurable resin disposed in the middle, so the thermosetting property of this part The resin can be arbitrarily selected. For example, a cheap epoxy resin may be selected for cost reduction, and a colored resin may be used for designability.

Here, in the method of forming the thermosetting resin layer disposed in the middle between the substrate and the photocatalyst layer, for example, a diluent is added to the thermosetting resin, then a mixture obtained by adding a curing agent is applied to the surface of the substrate, and solidified by heat treatment or leaving to form. do. Moreover, in the case of the photocurable resin layer of the layer arrange|positioned in the middle of a photocatalyst layer, light containing an ultraviolet-ray is irradiated instead of heat processing. Here, the diluent is added to decrease the viscosity of the mixed solution and to make it easier to apply the mixed solution to the surface of the substrate. Therefore, the diluent used herein may be basically any solvent as long as it can achieve the purpose. For example, water, ethanol, propanol and the like can be used.

In addition, as shown in FIGS. 49A and 49B, by filling the gaps formed in the photocatalyst layer exposed on the surface of the substrate by the above method with particles smaller than the gaps (pore particles: 4), it is preferable because the abrasion resistance can be further improved. do.

The size of the particles smaller than the gap should be smaller than the basic diameter or the average value of the irregularities to be generated. This is because the dirt is difficult to attach.

Specific examples are given below.

(Example 38)

On the surface of a 10 cm square alumina substrate, 10% by weight of siloxane resin, a diluent, and a curing agent are immersed in this order in tartan sol (dispersion treatment with an amino-based dispersant) having an average particle diameter of 0.01 μm. , to obtain a comparative sample by firing at 150° C. The sample was irradiated with various light sources for a predetermined time to obtain a sample. Deodorizing properties R when irradiated with light for the obtained sample₃₀(L) was evaluated.

Here, the characteristic R of deodorization at the time of light irradiation₃₀(L) is the concentration change rate after placing the sample in an 11-liter glass container at a distance of 8 cm from the light source (BLB fluorescent lamp 4W), injecting methyl mercaptan gas into the container so that the initial concentration is 3 ppm, and irradiating with light for 30 minutes.

The results are shown in (Table 22).

[Table 22]

<img file="KR100357482B1_D0022.tif" />

As a result, when the UV intensity is 1.69mW/cm2 or more, it exceeds 50% of the photometric measurement, and when it is 2mW/cm2 or more, the R of the deodorizing property₃₀(L) shows good results exceeding 70%. Here, the UV intensity is 1.69 mW/cm2 or more, indicating good results because a photocatalytic reaction occurs in the light-irradiated portion of the surface of the photocatalyst particle, and the thermosetting resin is preferentially decomposed and vaporized in the direction of the surface treatment agent and the light source, and the photocatalyst particle is exposed to the outside air. is interpreted as

(Example 39)

A solution obtained by adding a diluent and a curing agent to a siloxane resin was applied to the surface of a 10 cm square alumina substrate, dried at room temperature for 6 hours, and then added to a titanium oxide sol having an average particle diameter of 0.01 μm (dispersed with an amine-based dispersant) by 10 weight. % of the siloxane resin was coated with a mixture obtained by adding a diluent and a curing agent in this order, and 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. Deodorizing properties R when irradiated with light for the obtained sample₃₀(L) was evaluated. The results are shown in (Table 23).

[Table 23]

<img file="KR100357482B1_D0023.tif" />

As a result, the deodorizing property exceeds 60% when the UV intensity is 1.69 mW/cm2 or higher, and the deodorizing property R at 2mW/cm2₃₀(L) showed good results exceeding 80%. Here, when the UV intensity is 1.69 mW/cm 2 or more, good results are obtained because a photocatalytic reaction occurs in the light-irradiated portion of the surface of the photocatalyst particle, and a surface treatment agent attached to the light-irradiated surface in the surface of the photocatalyst particle that cannot be vaporized or decomposed by heat treatment thereof can be preferentially decomposed and vaporized, and as a result, it is interpreted that the photocatalyst particles are leaked to the outside air.

(Example 40)

A solution obtained by adding a diluent and a curing agent to a siloxane resin was applied to the surface of a 10 cm square alumina substrate, dried at room temperature for 6 hours, and then a titanium oxide sol having an average particle diameter of 0.01 μm (dispersion treatment with an amine-based dispersant) 10 A mixture obtained by sequentially adding a siloxane resin in weight %, a diluent, and a curing agent was applied, and calcined at 150°C. At this stage, the average particle spacing on the surface of the member was about 0.1 to 0.2 mu m. After that, after irradiating light (ultraviolet lamp) with an ultraviolet intensity of 2 mW/cm 2 for 3 days, R₃₀After confirming that (L) exceeded 80%, a tin oxide sol having an average particle diameter of 0.0035 µm was applied to the surface of 70% by weight relative to titanium oxide, and dried at 110°C to obtain a sample. In this sample, R₃₀(L) showed good results at 81%. In addition, when the perturbation test using a plastic eraser was performed, in the sample to which tin oxide was not added, scratches occurred at less than 5 perturbations, and the titanium oxide was peeled off. . From the above, it was confirmed that the abrasion resistance was improved by filling the tin oxide particles smaller than the gaps formed on the member surface.

From the above description, it is possible to provide a substrate having good photocatalytic activity even when a layer having a photocatalytic action treated at a low temperature of less than 300°C is formed.

In this method, metal fine particles are immobilized on the surface of a titanium oxide sol before adding a surface treatment agent such as a dispersant or surfactant to titanium oxide produced by a hydrothermal method or a sulfuric acid method.

Here, the fine metal particles refer to metal particles capable of capturing electrons when electrons and holes irradiated with light are generated on the titanium oxide when supported on titanium oxide. Specifically, Ag, Cu, Pt, Pd, Ni, Fe, Co, etc.

The photoreduction method is a simple method for immobilizing fine metal particles on the surface of the titanium oxide sol. The titanium oxide sol used herein is preferably prepared by a hydrothermal method or a sulfuric acid method, but is not limited thereto. Here, the sulfuric acid method is a method for synthesizing titanium oxide performed in the following procedure.

First, by reacting irmenite ore with sulfuric acid, Ti, Fe, etc. are converted into water-soluble sulfate, and extracted with water to prepare a sulfate solution of Ti and Fe as main components. Then SiO₂Remove insoluble suspensions such as Next, hydrolysis of titanyl sulfate in solution produces hydrous titanium oxide. This is a method for obtaining a titanium oxide sol by hydrolyzing the obtained hydrous titanium oxide by hydrothermal treatment under high temperature and high pressure water (generally, under saturated vapor pressure of 110°C or more and less than 200°C) using a pressure device such as an autoclave. A method for immobilizing fine metal particles on the surface of a titanium oxide sol by a photoreduction method is specifically carried out by the method shown below.

First, the titanium oxide sol suspension prepared by the hydrothermal method or the sulfuric acid method is made acidic or alkaline. It is because the isoelectric point of titanium oxide is pH 6.5, and it is easy to aggregate in neutral. In addition, in order to adjust to alkalinity, it is preferable to use ammonia. Alkali metals such as Na and K easily adhere strongly to titanium oxide, and if these metals first occupy the active site of titanium oxide, photocatalytic activity is reduced and Ag, Cu, P, Pd, Ni, Fe, Co, etc. This is because it prevents the titanium oxide from adhering to the active site.

Next, the titanium oxide sol suspension and the metal salt solution whose pH is almost the same are mixed with the titanium oxide sol suspension, and the metal is fixed by irradiating light containing ultraviolet rays. If necessary, the excess metal is precipitated and removed from the solution. Here, the metal salt solution refers to a solution of a salt and a solution containing a metal capable of capturing electrons when electrons and holes are generated when light is irradiated to the titanium oxide when supported on titanium oxide, and more specifically, Ag, It refers to a solution of a salt and solution containing Cu, Pt, Pd, Ni, Fe, Co, etc. Examples of the salt containing Ag, Cu, Pt, Pd, Ni, Fe, Co, etc. include silver nitrate, copper acetate, copper carbonate, copper sulfate, cuprous chloride, cupric chloride, chloroplatinic acid, palladium chloride, nickel chloride, cobalt chloride. , ferrous chloride, ferric chloride, and the like. In addition, although water, ethanol, propanol, etc. are used as a solvent, it is preferable to use the same kind as a titanium oxide sol suspension as much as possible. A pH adjuster is added to the solvent as needed. As a pH adjuster on the acid side, nitric acid, conversion, hydrochloric acid, etc. are used. In addition, ammonia is used as a pH adjuster on the alkali side.

Irradiation containing an ultraviolet-ray is performed paying attention to the point shown below. First, what is necessary is just to irradiate light containing an ultraviolet-ray as a light source, and an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, etc. are mentioned specifically,. Although the irradiation method of light containing ultraviolet rays is basically irrelevant, it is better to irradiate from above the container first. This is because there is no absorption of ultraviolet light by the container. Second, the distance between the light source and the container is preferably several centimeters to several ten centimeters. It is because illuminance will fall when it is too close. The irradiation time varies depending on the illuminance of the light source, but when irradiated for several seconds to several 10 minutes, the metal adheres strongly to the photocatalyst particles.

Next, a thin film formed by coating and heat-treating the above-described metal complex with titanium oxide sol is formed on the surface of the substrate to form a multifunctional material having a metal catalytic action.

The heat treatment is usually performed by sintering in the air using an electric furnace or a gas furnace or hydrothermal treatment using an autoclave, but is not limited thereto.

It is preferable that the average particle diameter of the titanium oxide particles in the titanium oxide film obtained by this method is 1 mu m or less. This is because the catalytic activity decreases due to a decrease in the specific surface area at a particle size larger than that.

In addition, a thin film obtained by applying and heat-treating the member having a photocatalytic action with the sol according to claim 1 is formed on the surface of the substrate with a binder interposed therebetween.

A specific method thereof differs depending on whether a thermoplastic binder or a thermosetting binder is used for the binder. One embodiment of each will be described below, but it is needless to say that other methods may be used as long as the above configuration is satisfied. Examples of the thermoplastic binder include a thermoplastic binder such as an acrylic resin, an inorganic glass material such as a glaze, and a solder. Moreover, as a thermosetting binder, a fluororesin, an epoxy resin, a siloxane resin, etc. are mentioned.

In the case of using a thermoplastic binder, a member having a photocatalytic action is manufactured as shown below. First, a thermoplastic binder is applied to the surface of the substrate. Next, a titanium oxide sol having metal particles supported thereon is coated and heat-treated. Here, the heat treatment is performed at a temperature lower than the heat resistance temperature of the substrate and higher than the softening point of the thermoplastic binder. By heat-treating at such a temperature, a part of the lower layer of the titanium oxide layer carrying the metal particles is buried in the binder layer, whereby the substrate and the titanium oxide thin film carrying the metal particles can be strongly bonded.

In the case of using a thermosetting binder, a member having a photocatalytic action is manufactured in the order shown below. First, a mixture prepared by sequentially adding a diluent and a curing agent to a thermosetting binder is applied to a substrate and cured by a method such as heat treatment. Next, a mixture prepared by sequentially adding a thermosetting resin, a diluent, and a curing agent to a titanium oxide sol carrying metal particles thereon is applied, and cured by heat treatment or the like.

In addition, a photocurable binder may be used in place of the thermosetting binder.

As such, in the titanium oxide sol produced by the hydrothermal method or the sulfuric acid method, etc., metal particles such as Ag, Cu, Pt, Pd, Ni, Fe, Co are added to TiO before the surface treatment agent such as a dispersant or surfactant is added.₂Since the active site of the titanium oxide sol is previously covered with metal particles such as Ag, Cu, Pt, Pd, Ni, Fe, Co by immobilization on the surface of the sol, surface treatment agents such as dispersants and surfactants are added in the post-process. However, these substances do not lose their activity by adsorbing to the active site of the titanium oxide sol. Therefore, it is possible to form a homogeneous film on the surface of the substrate capable of stably dispersing the photocatalyst sol by the action of a surface treatment agent such as a dispersant or surfactant, and at the same time, it is possible to form a homogeneous film on the surface of the substrate, and at the same time, it can be fired at a low temperature of less than 300 ° C. Ag, Cu, Pt, Pd, Ni, Fe, Co occupying the active sites of the titanium oxide sol while preventing the deterioration of the photocatalytic action by attaching the surface treatment agent to the active sites of the photocatalytic particle layer formed on the surface of the substrate The photocatalytic activity is improved by the electron trapping effect of metal particles such as

Specific examples are given below.

(Example 41)

Anatase-type titanium oxide sol is obtained by hydrothermal treatment of a liquid product obtained by adding water to titanium tetrachloride in a cold water bath at 140° C. in an autoclave. The obtained anatase-type titanium oxide sol was disperse|distributed in nitric acid. The pH of this dispersion was 0.8. In this, 3 to 5% by weight of a copper sulfate aqueous solution having pH adjusted to about 0.8 with nitric acid was added, and light containing ultraviolet rays was irradiated from above the container. At this time, a 4W BLB lamp was used as a light source, and light was irradiated for 15 minutes at a distance of about 10 cm from the solution. A dispersant of organic acetate was added to this solution to stabilize the sol. This sol was applied on a 15 cm square tile substrate and heat-treated at 150° C. to obtain a sample. Deodorizing properties R when irradiated with light for the obtained sample₃₀(L) and antibacterial properties were measured.

Deodorizing properties R when irradiated with light₃₀(L) is the concentration change rate after placing the sample surface in an 11-liter glass container 8 cm away from the light source (BLB fluorescent lamp 4W), injecting methyl mercaptan gas into the container so that the initial concentration is 3 ppm, and irradiating with light for 30 minutes.

In addition, the antibacterial properties were tested using E. coli (Escherichia Coli W3110 strain). 0.15 ml (10000-50000 CFU) of the bacterial solution was dripped onto the outermost surface of the sample sterilized in advance with 70% ethanol, placed on a glass plate (100×100), and brought into close contact with the outermost surface of the substrate to obtain a sample. After irradiating a white light (3500 lux) for 30 minutes, the bacterial solution of the irradiated sample was washed with sterile crayfish, recovered in 10 ml of physiological saline, and the survival rate of the bacteria was calculated as an average index. Evaluation criteria +++, ++, +, - are the same as before.

As a result R₃₀(L) showed good results with 85% antibacterial property +++.

(Comparative Example 42)

An anatase-type titanium oxide solution was obtained by hydrothermal treatment of a liquid product obtained by adding water to titanium tetrachloride in a cold water bath at 140° C. in an autoclave. The obtained anatase type titanium oxide sol was disperse|distributed in nitric acid. The pH of this dispersion was 0.8. To this solution, a dispersant of organic acetate was added and the sol was stabilized. This sol was applied on a 15 cm square tile base, and heat-treated at 150° C. to obtain a sample. Deodorization characteristic R at the time of light irradiation with respect to the obtained sample₃₀(L) and antibacterial properties were measured.

As a result, R₃₀(L) 5% antibacterial property - was insufficient.

(Example 43)

Anatase-type titanium oxide sol was obtained by hydrothermal treatment of a liquid product obtained by adding water to titanium tetrachloride in a cold water bath at 140° C. in an autoclave. The obtained anatase-type titanium oxide sol was dispersed in nitric acid. The pH of this dispersion was 0.8. Among them, an aqueous solution of 3 to 5% by weight of copper sulfate whose pH was adjusted to about 0.8 with nitric acid was added, 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 at a distance of about 10 cm from the solution. An organic acetate dispersant was added to this solution to stabilize the sol. Next, a mixture prepared by sequentially adding a diluent propanol and a curing agent to the surface of a 10 cm square alumina substrate in advance was applied in advance, and then dried at 100° C. on the sol prepared by the above method, 20 wt% based on the amount of titanium oxide A mixture prepared by sequentially adding a siloxane resin, propanol, and a curing agent of Deodorizing property R when irradiated with light for the obtained sample₃₀(L) was measured.

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

(Comparative Example 44)

Anatase-type titanium oxide sol was obtained by hydrothermal treatment of a liquid product obtained by adding water to titanium tetrachloride in a cold water bath at 140° C. in an autoclave. The obtained anatase type titanium oxide sol was disperse|distributed in nitric acid. The pH of this dispersion was 0.8. A dispersant of organic acetate was added to this solution to stabilize the sol. Next, a mixed solution prepared by sequentially adding propanol as a diluent and a curing agent as a siloxane resin in advance to the surface of an alumina substrate of 10 cm square was applied, and then dried at 100° C. on the sol prepared in the above method in an amount of 20% by weight based on the amount of titanium oxide A mixed solution prepared by sequentially adding a siloxane resin, propanol and a curing agent of Deodorization characteristic R at the time of light irradiation with respect to the obtained sample₃₀(L) was measured. As a result, R₃₀(L) was 22%, resulting in insufficient results.

From the above description, metal particles such as Ag, Cu, Pt, Pd, Ni, Fe, Co, etc. were mixed with titanium oxide before adding a surface treatment agent such as a dispersant or surfactant to the titanium oxide sol produced by the hydrothermal method or the sulfuric acid method. By immobilizing on the surface of the sol, it is possible to provide a member having sufficient photocatalytic action even when fired at a low temperature of less than 300° C. on a substrate having no heat resistance, for example, a plastic material.

The above examples are mainly anatase-type TiO₂was described, but below is rutile-type TiO₂describe about

50 is a rutile-type TiO₂It is a block diagram showing the manufacturing process of a multifunctional material using₂ to form a thin film. Rutile TiO₂ As a method of forming a thin film, TiO as a raw material₂ It is applied on the substrate using sol, Ti alkoxide, Ti sulfate, Ti chloride solution, etc., and then heat treatment or the like is performed.

TiO₂ TiO if sol is used₂Since its equipotential point is almost neutral at pH 6.5, it is easy to apply uniformly if applied on a substrate using an aqueous solution dispersed in acid or alkali. In this case, when the substrate 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 acid. In the case of alkali, ammonia and hydroxides containing alkali metals may be mentioned, but ammonia is particularly preferable because metal contaminants are not generated after heat treatment. Further, an organic acid, a phosphoric acid-based dispersant, a surface treatment agent, a surface active agent, and the like may be added to these dispersions. In addition, when the particle size is small, initial sintering occurs at a lower temperature and a photocatalyst thin film having excellent peel strength at low temperature can be obtained.₂ The average particle diameter of the string is 0.05 μm or less, preferably 0.01 μm or less.

As a coating method on a substrate, compared to the above raw materials spray coating, deep coating, roll coating, spin coating, CVD, electron beam deposition, sputtering, etc., it is possible in that a thin film can be formed at a low cost without requiring special equipment.

The heat treatment may be performed by sintering in the air using an electric furnace or a gas furnace, or by hydrothermal treatment using an autoclave or the like.

Meanwhile, Cu, Ag, Fe, Co, Pt, Ni, Pd, Cu₂At least one solution (aqueous solution containing metal ions) in O is prepared, and this is rutile-type TiO₂ It is applied on a thin film. Here, the application of the aqueous metal salt solution may be performed by a method in which the aqueous metal salt solution does not return to the back surface of the substrate. In the metal salt solution, water, ethanol, or the like may be used as the solution. When water is used, it is also effective to add alcohol, unsaturated hydrocarbon, etc. as a sacrificial oxidizing agent. In addition, it is preferable to use the solution as an ethanol solution because, for example, it does not cause rust due to metal substrates, the drying rate is fast, and it is harmless compared to other solvents such as ether, acetone, and methane. Then, in order to improve the carrying efficiency of the aqueous metal salt solution, it is dried at room temperature to about 110° C., and illumination containing a wavelength of 390 nm or less is irradiated to the metal salt to reduce metal ions to reduce the rutile-type TiO.₂ The metal is deposited and immobilized on a thin film. Here, the lamp used for irradiation uses an ultraviolet lamp, a BLB (block light blue) lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, and the like. In this case, the irradiation may be performed so that the light hits the irradiation surface vertically in order to improve the irradiation efficiency.

Specific examples are given below.

(Example 45)

TiO with an average particle diameter of 0.01 μm₂ The ammonia dispersing power of the sol is applied by spray coating on an alumina substrate in a 10 cm square and calcined at 900°C to rutile TiO.₂ A thin film was formed. Subsequently, this rutile-type TiO₂ An aqueous solution of copper acetate was applied to the thin film by spray coating, and then light reduction (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, the irradiation time was 10 seconds) to obtain a sample. The photoactivity A(L) of the obtained sample was evaluated. Photoactivity A(L) represents the absolute value of the tendency when the reaction curve is linearly similar when the gas concentration is on the Y-axis and the reaction time is on the X-axis. That is, if the concentration at time t is Xt,

<img file="KR100357482B1_D0024.tif" />

becomes Therefore, a certain decomposition gas is passed on the photocatalyst thin film irradiated with light containing ultraviolet rays, and is obtained by observing the decrease in the concentration of the decomposition gas at the lapse of time t. In this embodiment, the sample is installed in a cylindrical container with a diameter of 26 cm x height of 21 cm, which uses methyl mercaptan, an odor component, as the decomposition gas, and the initial concentration of methyl mercaptan is adjusted to 2 ppm, and a 4W BLB fluorescent lamp is placed 8 cm away from the sample. was obtained by observing the temporal change of methyl mercaptan concentration.

The obtained results are shown in FIGS. 51 and 52 . 51 and 52 are graphs showing the relationship between the sample concentration in the solution and the photoactivity A(L), of which, FIG. 51 is a case where the sprayed copper acetate aqueous solution is dried and then photoreduced, and FIG. The case where the copper acetate aqueous solution of the state which is not dried is shown with photoreduction|reduction.

When the copper acetate aqueous solution in the state of being sprayed and not dried is photoreduced in FIG. 52, A(L) is 3×10 even when the Cu concentration in the solution is increased from 0.001% by weight to 0.1% by weight.^-5 It does not change to the extent that it is saturated.

On the other hand, in the case of photoreduction after drying the sprayed copper acetate aqueous solution of FIG. 51, at 0.001% by weight, 2 × 10^-5It was almost the same value as the case without drying, but when it was increased to 0.1% by weight, it was 1×10^-2 It was observed that A(L) improved dramatically.

(Example 46)

In the same manner as in Example 45, rutile-type TiO on top tiles and wall tiles₂ A thin film is formed, and this rutile-type TiO₂ Concentration of metal components in solution and odor removal rate R when Cu is immobilized on a thin film by photoreduction (after copper acetate aqueous solution application and drying)₃₀53 and 54 show the results of examining the relationship between .

From these figures, it can be seen that if the concentration of the metal component in the solution is increased to a certain extent by performing the photoreduction treatment after drying, the odor component can be removed even if the substrate is a tile material.

(Example 47)

TiO with an average particle diameter of 0.01 μm₂ Ammonia dispersion of the sol is applied on a tile substrate of 15 cm square by spray coating, and it is fired at various temperatures to form rutile TiO.₂ A thin film was formed. Subsequently, this rutile-type TiO₂ A copper acetate aqueous solution was applied to the thin film by spray coating, and then light reduction (the light source was a 20-watt BLB lamp, the distance from the light source to the sample was 10 cm, the irradiation time was 10 seconds) to obtain a sample. Deodorizing property R for the obtained sample₃₀evaluated.

The obtained result is shown in FIG. R at 900°C (10% open porosity)₃₀ It is better than the case of rutile without supporting metal. In addition, if the temperature is raised to 1000 °C (open porosity 3%), R in the sample not carrying the metal₃₀The value drastically decreased, and a slight decrease was observed even in the Cu-added sample. As such, the deodorization characteristic is lowered at 1000°C compared to when it is 900°C due to two reasons. One is rutile-type TiO in optical contact that can come into contact with the decomposition gas due to the decrease in open porosity.₂ It is the fall of the area of the fall of a thin film. It is thought that the reason that the deodorizing property deteriorated in the sample which did not carry a metal is mainly due to the reason. Another reason is that the area in which the metal particles precipitated by the photoreduction method can exist is also reduced as the open porosity is lowered. This is because the average free path in electron movement becomes large.

Also, Fig. 56 shows the relationship between the Ag and Cu concentrations in the solution at the time of the coating film and the color difference. From this figure, it can be seen that Cu is less in color difference and brightness change than Ag, and the coloration is not conspicuous. In addition, this difference in coloration is due to the fact that 0 and monovalent Cu were detected by analysis by ESCA (electron beam fluorescence for chemical analysis), etc. for the Cu system, so it is thought that the monovalent component that is difficult to color is affected. .

(Example 48)

TiO with an average particle diameter of 0.01 μm₂ Ammonia dispersion of the sol is applied on a 15 cm square tile substrate by spray coating and calcined at various temperatures to form rutile TiO₂ A thin film was formed. Subsequently, this rutile-type TiO₂ An aqueous solution of silver nitrate was applied to the thin film by spray coating, and then, a sample was obtained by light reduction (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, the irradiation time was 10 seconds). With respect to the obtained sample, rutile-type TiO₂ Porosity and deodorization characteristics of thin film R₃₀ And the result of evaluation about abrasion resistance is shown in FIG.

When the porosity is 10% or more, good deodorization properties are exhibited, and when the porosity is less than 40%, the abrasion resistance can be made more than .

About abrasion resistance, perturbation friction using a plastic eraser was performed, and the change of an external appearance was compared and evaluated. The evaluation index is shown below.

: No change for 40 round trips

: A scratch occurs after 10 to 40 perturbations, and the titanium oxide film peels off

Δ: A scratch occurs after 5 to 10 perturbations, and the titanium oxide film peels off

×: A scratch occurs in perturbation of 5 times or less, and the titanium oxide film is peeled off

(Example 49)

TiO with an average particle diameter of 0.01 μm on a 10 cm square alumina substrate on which a gray layer is formed in advance.₂ Ammonia dispersion of sol is applied by spray coating method, and it is calcined at 850 °C or higher and lower than 1000 °C to rutile TiO₂ A thin film was formed. Subsequently, this rutile-type TiO₂ A silver nitrate aqueous solution was applied to the thin film by spray coating, and then light reduction (the light source was a 20W BLB lamp, the distance from the light source to the sample was 10 cm, the irradiation time was 10 seconds) to obtain a sample. The obtained samples were evaluated for antibacterial properties, abrasion resistance, peeling resistance, stain resistance, acid resistance, alkali resistance, and Ag colorability.

The antibacterial properties were tested using Escherichia Coli strain W3110. 0.15 ml (1-50000 CFU) was added dropwise to the bacteria on the outermost surface of the multifunctional material previously sterilized with 70% ethanol, placed on a glass plate (100×100), and brought into close contact with the outermost surface of the substrate to obtain a sample. After irradiating a white light (3500 lux) for 30 minutes, the bacteria solution of the irradiated sample and the sample maintained under light-shielding conditions was washed with sterile gauze, recovered with 10 ml of physiological saline, and the survival rate of the bacteria was obtained as an index for evaluation. Evaluation indicators +++, ++, +, - are the same as in the previous section.

The peeling resistance test is a more stringent test of the abrasion resistance test, and a sand eraser (LION TYPEWRITER ERASER 502) with a greater shear force was used instead of a plastic eraser. A specific evaluation method is performed by rubbing the surface of the sample with a sand eraser 20 times with equal force, and visually comparing the scratched state with the standard sample. Evaluation criteria are shown below.

: No change at all

: Check a slight change in light

: Slight change confirmed

× : Check changes at a glance

The stain resistance test is a test about the difficulty of stain adhesion. A specific evaluation method is carried out by making a stain on the sample surface in 0.5% methylene blue aqueous solution, washing with water after drying, and visually observing the presence or absence of stain. Evaluation criteria are shown below.

: Completely removes stains

: The color of the stain is unknown, but slightly reversed

: A thin stain color remains

×: A clear stain color remains

For acid resistance, after immersion in 10% HCl aqueous solution for 120 hours, rutile-type TiO loaded with Ag on the surface of the substrate₂ The abnormality of the thin film layer was visually observed and evaluated. Evaluation criteria are shown below.

: no change

: Slight discoloration

: slight discoloration

×: definite discoloration

For alkali resistance, rutile-type TiO loaded with Ag on the surface of the substrate after 120 hours of immersion in 5% NaOH aqueous solution₂ The abnormality of the thin film layer was visually observed and evaluated. The criteria for evaluation are shown below.

: no change

: Very slight discoloration

: slight discoloration

×: definitely discolored

The Ag colorability was evaluated by visually observing a sample to which Ag was not added. The criteria for evaluation are shown below.

: No coloration

: very faintly colored

: slightly colored

×: There is also brown coloration

The evaluation results of the above 7 items are summarized in (Table 24), and the influence of the film thickness and the firing temperature on the antimicrobial properties is shown in (Table 25).

[Table 24]

The relationship between the thickness of the photocatalyst thin film and various properties

<img file="KR100357482B1_D0025.tif" />

[Table 25]

Effects of film thickness and firing temperature on the antibacterial properties of photocatalyst thin films

<img file="KR100357482B1_D0026.tif" />

Regarding the antibacterial properties, in the range of 0.1 μm to 1 μm in thickness of the photocatalyst thin film produced in this example, if the firing temperature is properly adjusted, good results are shown as +++. However, as shown in Table 24, when the film thickness was as thin as 0.2 μm or less, a tendency of slightly lowering antibacterial properties as ++ was observed in the sample calcined at a high temperature of 980°C. This is considered to be because the photocatalyst thin film is locally buried in the grayscale layer due to the softening of the grayscale layer. In addition, although Ag itself has antibacterial activity, the tendency of this antibacterial activity to depend on the firing temperature is that the antibacterial activity of the composite member manufactured by the method of the present application is different from the antibacterial activity of Ag.₂ It has been shown that the characteristics of the thin film are involved (since Ag is supported after firing as described above).

In addition, it is considered that all of the penetration into the gray layer of the photocatalyst thin film accompanying the softening of the glaze layer occurs to some extent in the sample. It was confirmed that it could be held in the outermost layer.

With respect to abrasion resistance, all of the photocatalyst thin films prepared in this Example had a good result with a double mark within the range of 0.1 µm or more and 1 µm or less. In order to compare these results, in the sample prepared without the intervening graze by the same manufacturing method, it was clearly an excellent result with respect to Δ. This is considered to be due to the fact that a part of the lower layer of the photocatalyst thin film is buried in the graze layer due to the softening of the gray at the time of firing by interposing the grey.

On the other hand, in the peeling resistance test, it was observed that in the case of 0.1 µm or more and 0.4 µm or less, , in the case of 0.4 µm or more and 0.9 µm or less, , and in 1 µm, ×, and a tendency to deteriorate with increase in the film thickness of the photocatalyst thin film. It is considered that this is because peeling becomes easy when the ratio of the embedding thickness to the glaze with respect to the film thickness increases. In addition, the fact that there was no abnormality in the abrasion resistance test but deteriorated in the peel resistance test is due to the difference in the magnitude of the shear force.

Regarding fouling resistance, it was observed that the film thickness of the photocatalyst thin film became when the thickness of the photocatalyst thin film was 0.1 μm or more and 0.4 μm or less, when it was 0.4 μm or more and 0.9 μm or less, and x when it was 1 μm.

Regarding alkali resistance, all of the photocatalyst thin films produced in this example showed good results within the range of 0.1 µm or more and 1 µm or less. However, in the case of 0.4 µm or more and 1 µm or less, it is , and in 0.1 µm or more and less than 0.4 µm, it is , and the thinner the film thickness shows a preferable value. As for the Ag colorability, it was observed that the thickness of the photocatalyst thin film became when the thickness of the photocatalyst thin film was 0.1 μm or more and 0.4 μm or less, when it was 0.4 μm or more and 0.9 μm or less, and × when the thickness of the photocatalyst thin film increased. This trend is consistent with pollution resistance.

According to the above 7 experiments, the film thickness of the photocatalyst thin film is preferably 0.1 µm or more and 0.9 µm or less, preferably 0.1 µm or more and 0.4 µm or less. was recognized

Moreover, the design characteristic also changes with the film thickness. That is, in the case of 0.2 µm or more and less than 0.4 µm, the appearance of the color, shape, or combination thereof is assured as it is, without the appearance of an iris-colored pongee pattern due to the interference action between visible light and the photocatalyst thin film. .

(Example 50)

TiO with an average particle diameter of 0.01 μm₂ Ammonia dispersion of the sol is applied by spray coating on a 15 cm square tile substrate and calcined at 900 ° C.₂ A thin film was formed. Next, the amount of copper acetate aqueous solution (solution concentration of 0.2 wt%, 0.5 wt%, 1 wt%) was changed on the surface of the tile and applied by a spray coating method, followed by light reduction (the light source is the distance from the 20W BLB lamp light source to the sample) 10 cm, irradiation time 30 seconds) to obtain a sample. Antimicrobial properties were evaluated for the obtained samples. Moreover, Cu loading amount collect|recovered the residual aqueous solution after irradiation, and computed it from the difference of the copper amount of an initial stage and the collect|recovered copper amount.

Fig. 58 shows the relationship between the survival rate of the bacteria at the time of light irradiation with Cu loading (L) and at the time of light blocking (D). 58 shows the following.

First of all, the antibacterial property is improved by Cu loading. Next, the antibacterial activity is improved in the case of light irradiation (L) with a smaller amount of Cu supported than at the time of light blocking (D). This is a rutile-type TiO that recovers photoactivity by Cu loading during light irradiation (L).₂ This is because the thin film acts as a photocatalyst. From the figure, it improves to ++ in an increase of 0.2 μg/cm 2 or more, and +++ in an increase of 0.3 μg/cm 2 or more.

It is known that Cu itself also has an antibacterial action, and therefore, when the amount of Cu supported is increased even during light blocking, an improvement in the antibacterial property is recognized. In this case, it improves to ++ at the loading of 0.7 μg/cm 2 or more and +++ at the loading of 1.2 μg/cm 2 or more.

Therefore, when evaluated at ++ level, 0.12 μg/cm 2 or more and less than 0.7 μg/cm 2 It is considered to be a unique effect due to the combination of the rutile-type TiO2 thin film and the rutile-type TiO2 thin film.₂ The presence of the thin film can improve the amount of Cu supported. The ability to reduce the amount of Cu supported is an important property, especially when this composite member is used for water circulation, and it is used in environments where Cu can elute in water, for example, it is used in washbasin or sanitary ware. Even in this case, the elution amount can be suppressed to a small extent.

In addition, in the case of Cu, Cu₂The same effect is obtained for the form of O. This is because the monovalent Cu is detected by ESCA on the surface during photoreduction.⁺² 1 Cu⁺This is because the photoactive recovery effect is observed despite being partially formed.

On the other hand, by setting the Cu loading amount to be 0.7 μg/cm 2 or more, more preferably 1.2 μg/cm 2 or more, good antibacterial properties can be obtained regardless of the presence or absence of light irradiation.

59 is a relationship between the amount of Cu applied and the amount of Cu supported when the Cu concentration in the solution is 1% by weight. In order to set it to 0.7μg/cm2 or more, it is good to set it to 0.2mg/cm2 or more and 1.7mg/cm2 or less, and to set it to 1.2μg/cm2 or more, it is good to set it to 0.3mg/cm2 or more and 2.4mg/cm2 or less.

(Example 51)

TiO with an average particle diameter of 0.01 μm₂ Ammonia dispersion of the sol is applied on a 15 cm square tile substrate by spray coating and calcined at 900 ° C.₂A thin film was formed . Then, the application amount of silver nitrate aqueous solution (solution concentration of 0.2 wt%, 0.5 wt%, 1 wt%) is changed on the surface of this tile and applied by spray coating, and then light reduction (the light source is a 20 watt BLB lamp, from the light source to the sample) distance of 10 cm, irradiation time 30 seconds) to obtain a sample. Antimicrobial properties were evaluated for the obtained samples. The Ag loading amount was calculated from the difference between the initial capacity and the recovered capacity by recovering the aqueous solution of the tile in distilled water after irradiation.

Fig. 60 shows the relationship between the amount of Cu supported and the bacterial viability during light irradiation (L) and light blocking (D). It can be seen from Fig. 60 that the following

First of all, unlike the case of Cu, the curves of the bacterial survival rate at the time of light irradiation (L) and at the time of light blocking (D) overlapped. Therefore, it is much larger and the effect occurs with a very small amount of loading, so it is considered that the difference between the loading amount of the sample at the time of light irradiation (L) and at the time of light blocking (D) was accepted within the experimental error range.

Further, from Fig. 60, when the Ag loading amount is set to 0.05 μg/cm 2 or more, preferably 0.1 μg/cm 2 or more, good antibacterial properties can be obtained regardless of the presence or absence of light irradiation.

On the other hand, FIG. 61 shows the relationship between the amount of silver supported and the color of the sample not already supported. When the amount of silver supported exceeds 1 μg/cm 2 , the color difference rapidly becomes large and exceeds this. In general, when the color difference is greater than this, the color difference becomes conspicuous. When silver adheres, it changes from brown to black, and it is undesirable because it looks bad in appearance. Therefore, it is desirable to suppress the color difference to 2 or less, and for this purpose, it can be seen that the amount of silver supported should be 1 μg/cm 2 or less. The color difference characteristics were measured with a spectroscopic color difference meter.

However, in the above embodiment, since the activity of the photocatalyst prevents or restores the activity as much as possible from the decrease in activity caused by the site being covered with a surface treatment agent, nocturnal molecular substance, dust, etc., the active point of the microparticles having photocatalytic activity is silver, copper, platinum , disclosed a method of covering with fine metal particles such as palladium, gold, nickel, iron, cobalt, zinc, etc., but since these metals are colorless metals, if applied in a large amount, their own color is attached to the surface of the substrate, and the color and shape of the substrate It will damage the design of the back.

Therefore, a decolorization method that does not impair the design of the color, shape, etc. of the substrate while maintaining high photocatalytic activity will be described below.

As a basic method, metal particles are contained by two processes: a step of immobilizing metal particles on particles having photocatalytic activity, and a step of reacting electric metal particles with an aqueous solution or gas to form a colorless or white salt on at least the surface of the metal particles. by preparing a catalyst that

Here, the order of performing the above two steps may be performed from any one. That is, after the colorless metal particles are immobilized on the particles having photocatalytic activity, the metal particles and the aqueous solution gas are reacted to form a colorless or white salt at least on the surface of the metal particles, and the colorless metal particles and the aqueous solution or gas After reacting to form a colorless or white salt at least on the surface of the metal fine particles, it may be immobilized on the particles having photocatalytic activity.

In addition, the particles having photocatalytic activity may be fixed to the substrate after mixing the colored metal fine particles. In this case, for example, in the case of mixing particles having photocatalytic activity and colored metal fine particles, the process of applying the electric mixture to the substrate, the process of firing and fixing the electric mixture to the substrate, the process of reacting with the gas to make at least the surface of the metal fine particles colorless Alternatively, the steps of forming a white salt are sequentially performed.

Further, the step of fixing the mixture to the substrate by firing and the step of reacting with a gas to form a colorless or white salt on at least the surface of the metal fine particles can be performed simultaneously.

The colored metal microparticles are metal microparticles that have a small ionization tendency, such as silver, copper, platinum, palladium, gold, nickel, iron, and cobalt zinc, and are easily reduced.

When a colorless or white salt is formed by reaction with an aqueous solution, or when a catalyst contained in fine metal particles is used for a liquid or the like, the colorless or white salt formed is preferably sparingly soluble or insoluble.

When a catalyst containing fine metal particles is fixed to a substrate and used, the catalyst containing metal fine particles may be prepared by fixing the particles having photocatalytic activity to the substrate in advance, and after preparing the catalyst containing metal fine particles , may be fixed to the substrate.

In the case of producing particles containing metal microparticles by fixing particles having photocatalytic activity to a substrate in advance, a step of forming a particle layer having photocatalytic activity on a substrate, other steps of immobilizing colored metal particles, electro-colored metal It is by performing the process of forming a colorless or white salt in order to cover the mirinja.

The process of forming a colorless or white salt by covering the colored metal fine particles is, for example, a solution capable of forming a colorless or white salt on at least the surface of the metal fine particles by reacting with the colored metal fine particles. or a method of contacting the metal fine particles with a reaction gas capable of reacting with the colored metal fine particles to form a colorless or white salt on at least the surface of the metal fine particles.

In the salt of the colored metal fine particles, the colorless or white one is preferably a sparingly soluble or insoluble salt. This is because a salt can be easily formed on at least the surface of the metal fine particles in an aqueous solution reaction, and it can be used simply in an environment with water.

Examples of the colorless or white salts of the colored metal fine particles include silver chloride, silver bromide, silver iodide, silver oxalate, silver thiosulfate, silver cyanide, silver rhodanide, cuprous chloride, cuprous bromide, cuprous cyanide. , cuprous iodide, cuprous oxide, zinc phosphate, zinc oxalate, zinc cyanide, palladium cyanide, zinc sulfide, zinc carbonate, ferrous carbonate, zinc carbonate, and the like. The solution capable of forming the salt is, for example, in the case of silver chloride, potassium chloride solution, sodium chloride solution, ammonium chloride solution, ferrous chloride solution, in the case of phosphorus iodide, potassium iodide solution, sodium iodide solution, iodine chloride solution A ferrous solution, hydrogen peroxide, ozone, etc. may be mentioned, but are not limited thereto, and a soluble salt solution each containing salt ions may be widely used.

In addition, the reaction gas capable of forming the salt may be widely used as long as it contains an anion element of various salts. For example, if the salt is an oxide such as zinc oxide or cuprous oxide, by heating in the atmosphere, in oxygen, or in a water vapor layer, or by reacting with an oxidizing agent such as ozone, the surface of the metal fine particles can be oxidized to form an oxide layer on the surface. have.

Specific examples are given below.

(Example 52)

A titanium oxide sol having an average particle diameter of 0.01 μm was applied to the surface of a 15 cm square tile substrate, and then heat-treated at 900° C. to form a rutile-type titanium oxide thin film. The same sample as mentioned above was made into the comparative sample (1).

Then, an aqueous silver nitrate solution was applied by a spray coating method, and a 20 W BLB lamp was irradiated as a light source for 10 minutes, and silver was fixed to a rutile-type titanium oxide thin film or the like. At this time, the loading amount of silver was 1.2 μg/cm 2 , and it appeared brown. The sample which remained in this relationship was made into the comparative sample (2).

Then, 0.1 mol/m of potassium iodide aqueous solution was applied and reacted on the comparative sample (2) at a rate of 1 cc/cm 2 . As a result, the surface of the sample turned yellowish white and whitened. This is thought to be due to the formation of a silver iodide layer. This sample was used as the implementation sample (1).

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

The color difference was measured with a spectroscopic color difference meter. In this case, the standard sample was used as Comparative Sample 1. The results are shown in FIG. 62 . As a result, compared to the color difference of 3.5 in Comparative Sample 2, by treatment in an aqueous potassium iodide solution, the actual sample 1 decelerated to a color difference of 1 and the degree of coloration decreased.

The photoactivity was measured in the ?pH test. The results of photoactivity and deodorization properties are shown in FIG. 6.3. By carrying silver by comparison with Comparative Samples 1 and 2, the photoactivity was recovered in Comparative Sample 2, and ΔpH was also R₃₀(L) also showed good results. In addition, when comparing sample 1 and comparison sample 2, ΔpH is also R₃₀(L) also became approximately the same value, and it was found that good properties could be maintained without change in photoactivity even by decolorization treatment.

In addition, the antibacterial properties were tested using E. coli (Escherichia Coli W 3100 strain). 0.15 ml of the bacterial solution on the outermost surface of the sample sterilized with 70% ethanol in advance⁴ CFU) was added dropwise, placed on a glass plate (100×100 mm), high and in close contact with the outermost surface of the substrate, and used as a sample. The number of bacteria in the sample (L) irradiated with a white light (3500 lux) for a predetermined time and the sample (D) maintained under light-shielding conditions were wiped with sterile gauze, recovered with 10 ml of physiological saline, and evaluated by irradiating the number of viable bacteria.

The results regarding the antimicrobial properties are shown in FIG. 64 . Since the comparative sample 1 did not contain silver, the antibacterial effect was not recognized during light-shielding (D). On the other hand, in Example 1, although the silver surface was changed to the compound in the decolorization treatment, the antibacterial effect at the time of light blocking (D) was recognized. In addition, a stronger antibacterial effect was observed during light irradiation (L), and the photocatalytic activity recovery effect of the rutile-type titanium thin film was also observed, not the antibacterial effect of silver.

(Example 53)

After applying the glaze to the 15 cm square sanitary ware molding resin, after firing at 1100 to 1200 ° C, anatase titanium oxide sol with an average particle diameter of 0.01 μm is applied, and fired at 900 to 1000 ° C. Rutile-type oxidation on the base material for baking sanitary ware A titanium thin film was fixed.

Then, an aqueous solution of silver nitrate was applied thereon and irradiated with ultraviolet rays to precipitate silver on the titanium oxide thin film. Again, an aqueous ferric chloride solution was applied thereon, and when irradiated with ultraviolet light, the color was decolorized and the color difference decreased from 3 to 0.3. In addition, the antibacterial properties showed good results confirming that less than 10% of the original number of bacteria was alive by contacting the sample for 30 minutes when both light was irradiated and light was blocked.

(Example 54)

After applying the glaze to the sanitary ware molded base of 15 cm square, after firing at 110°C to 1200°C, anatase titanium oxide sol with an average particle diameter of 0.01 μm is applied, fired at 900 to 1000°C, and rutile-type oxidation on the sanitary ware molded substrate A titanium thin film was fixed.

Then, an aqueous solution of silver nitrate was applied thereon, and ultraviolet light was irradiated to precipitate silver on the titanium oxide thin film. Again, the sample was left to stand in a desiccator with an ozonizer (ozone concentration of 10 ppm) for about 2 hours to decolorize. It showed good results, confirming that less than 10% of the original number of bacteria was alive.

(Example 55)

After applying the glaze to a 15cm square sanitary ware molded base, it was fired at 1100°C to 1200°C. A mixed solution of anatase titanium oxide sol and silver nitrate aqueous solution having an average particle diameter of 0.01 μm dispersed in an aqueous nitric acid solution was applied thereon, then fired, and a titanium oxide thin film was fixed on the sanitary ware molded base material. At this time, when calcined at less than 700 °C, the color was brown, but when calcined at 700 °C or higher, the color was discolored. It is thought that this is because this surface reacts with atmospheric components. In addition, if the antibacterial property is measured for a sample in which an anatase-type titanium oxide thin film is fixed on a sanitary ware molded base material after firing at 850°C, less than 10% of the original number of bacteria is alive by contacting the sample for 3 hours with light blocking during light irradiation. was confirmed, and good results were obtained.

(Example 56)

After applying the glaze to a 15 cm square sanitary ware molded base, it was fired at 1100°C to 1200°C. Again, anatase titanium oxide sol having an average particle diameter of 0.01 mu m was applied thereon, fired at 900 to 1000 DEG C, and a rutile-type titanium oxide thin film was fixed on a base material for molding sanitary ware.

Then, an aqueous solution of silver nitrate was applied thereon, and ultraviolet light was irradiated to precipitate silver on the titanium oxide thin film. When hydrogen peroxide solution was applied on it again, it was discolored. In addition, the antibacterial property obtained good results confirming that less than 10% of the original number of bacteria was alive by contacting the sample for 3 hours when blocking the light when irradiated with light.

Next, rutile-type TiO₂ A point is described in which particles and tin oxide are mixed to improve the density and adhesion of the photocatalyst thin film and at the same time improve the activity.

The formation method of the photocatalyst thin film is by either of the following two methods.

One is TiO₂ TiO by pre-mixing the sol and tin oxide sol₂ The sol and tin oxide are mixed in a basic aqueous solution. The reason that both exhibit good dispersion is because they are on the alkaline side from an electrochemical view. Examples of the basic aqueous solution include ammonia, hydroxides containing alkali metals or alkaline earth metals, but ammonia is particularly preferable because metal contaminants are not generated after heat treatment. Moreover, you may add organic type and phosphoric acid type dispersing agent, a surface treatment agent, and surface active agent again to these dispersion liquids.

As a coating method, there is a method of applying the mixed solution by spray coating, deep coating, roll coating, spin coating, CVD, electron beam deposition, sputtering, etc., but any of them may be used, or a method other than these may be used. However, spray coating, deep coating, and roll coating do not require special equipment compared to CVD, electron beam deposition, sputtering, etc., and have the advantage of being able to coat at a low cost.

After application, the film may be dried before firing. Drying is preferably performed at room temperature to about 100°C.

The calcination temperature is performed at a temperature sufficient to produce rutile under these conditions. The temperature is 830 DEG C or higher in the presence of tin oxide under normal pressure.

TiO₂It is not necessary to form a solid solution of and tin oxide. TiO₂In order to form a solid solution of tin oxide with tin oxide, it is necessary to maintain it at a high temperature for a long time, because the production efficiency is poor.

Another method is rutile-type TiO₂ It is a method in which tin oxide is added thereon after formation of the thin film, and then sintered.

In this method, first TiO₂A starting material containing Here, as a starting material, TiO₂ Sol, Ti alkoxide, Ti sulfate, Ti chloride solution, etc. are used. TiO₂ TiO when sol is used₂ Since its isoelectric point is neutral with a pH of about 6.5, it is easy to apply uniformly if applied on a substrate using an aqueous solution dispersed in acid or alkali. In the case of ceramics, tiles, ceramics, etc., any dispersion of acid or alkali may be used. Examples of the acid include nitric acid, sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, and organic acid. Examples of the alkaline aqueous solution include ammonia, hydroxides containing alkali metals or alkaline earth metals, but ammonia is particularly preferable because metal contaminants are not generated after heat treatment. Further, to these dispersions, an organic acid, a phosphoric acid-based dispersant, a surface treatment agent, and a surface active agent may be added. In addition, TiO of the starting material₂ The average particle diameter of the sol is 0.05 μm or less, and 0.01 μm is good for the windshield. This is because when the particle size is small, initial sintering occurs at a low temperature, so that a thin photocatalyst layer having excellent peel strength at a low temperature can be formed. The coating method on the substrate includes a method of coating them by spray coating, deep coating, roll coating, spin coating, CVD, electron beam deposition, sputtering, etc. However, spray coating, deep coating, and roll coating do not require special equipment compared to CVD, electron beam deposition, sputtering, etc., and have the advantage of being able to coat at a low cost. After application, the film may be dried before firing. Drying is preferably performed at room temperature to about 100°C.

Next, the applied composite member is fired. Firing is performed at a temperature that produces rutile. Its temperature is 900°C or higher under normal pressure.

After that, the starting material used as a source of Sn is applied again on the cooled and solidified composite member and fired. As a starting material used as a source of Sn, there are tin oxide and the like. A basic aqueous solution may be used for 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 basic aqueous solution include hydroxides containing ammonia, alkali metals or alkaline earth metals, but they are particularly preferable in that metal contaminants are not generated after heat treatment. Further, to these dispersions, an organic acid, a phosphoric acid-based dispersant, a surface treatment agent, and a surface active agent may be added. The coating method on the substrate includes a method of coating them by spray coating, deep coating, roll coating, spin coating, CVD, electron beam deposition, sputtering, etc. However, spray coating, deep coating, and roll coating do not require special equipment compared to CVD, electron beam deposition, sputtering, etc., and have the advantage of being able to coat at a low cost. After application, the film may be dried before firing. Drying is preferably performed at room temperature to about 100°C. The calcination temperature may be a temperature at which the organic additive component is evaporated from the tin oxide. This temperature is 300°C or higher under normal pressure. Also TiO₂In order to form a solid solution of tin oxide and tin oxide, it is necessary to maintain it at high temperature for a long time, and this is because the production efficiency is poor.

In addition, rutile-type TiO on the surface of the substrate₂and a thin film of a mixture of tin oxide with a crystal diameter of less than 001 μm, and again on it, Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu₂At least one metal among O may be fixed.

These metals have an electron trapping action, whereby rutile TiO₂It improves the photocatalytic activity of a thin film made of a mixture of tin oxide with a crystal diameter of less than 0.01 μm.

In particular, Cu and Ag have antibacterial activity by themselves, and since activity in the dark cannot be imparted with respect to antibacterial activity, it is possible to have antibacterial activity to a certain extent without light irradiation. Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu₂An aqueous solution of at least one metal salt in O is applied, and then immobilized by a photoreduction method or a heat treatment method.

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

There are spray coating methods or dip coating methods for coating the aqueous metal salt solution, but the amount of solution used can be reduced, it can be applied uniformly, it is easy to control the film thickness, and it is not attached to the back side. The spray coating method is more preferable for the reason that it is possible to do it.

In the case of the photoreduction method, rutile-type TiO is irradiated with light containing its ultraviolet rays to reduce metal ions.₂Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu on a thin film of a mixture of tin oxide with a crystal diameter of less than 0.01 μm₂At least one metal among O is immobilized.

The light source for irradiating the light containing ultraviolet light should just be capable of irradiating light containing ultraviolet light, and specifically, any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, etc. may be sufficient. In the method of irradiating light containing ultraviolet rays, it is preferable to arrange the sample so that the light hits the irradiation surface perpendicularly. This is because the research efficiency is the best.

The distance from the light source of the sample is preferably 1 cm to 30 cm. If the distance is too short, the light is not irradiated with uniform illuminance over the entire sample surface, and non-uniformity occurs in the adhesion of the metal species. It is difficult to attach firmly.

In the case of the heat treatment method, the metal is then fixed by heating to a temperature sufficient to fix the metal. The temperature is preferably 100°C or higher. However, since the metal is oxidized when treated at a high temperature of, for example, 800° C. or higher, in that case, it is limited to metals that do not lose the trapping effect or lose antibacterial properties even when oxidized. That is, it is limited to Ag and Cu. In the case of Ag and Cu, since the electron trapping effect or antibacterial property is not lost even when calcined at a high temperature, the manufacturing method shown below is also possible. That is, TiO₂It is a method in which sol and tin oxide are mixed in advance and applied to the surface of a substrate, followed by application of an aqueous metal salt solution, followed by firing. According to this method, it is possible to finish the firing process once, and it is effective in productivity improvement and manufacturing cost reduction.

Hereinafter, specific examples are given.

(Example 56)

TiO with a crystal diameter of 0.01 μm₂A suspension is prepared by adding 4 to 6% by weight of the sol to an aqueous ammonia solution adjusted to pH 11. In a separate container, 10 wt% of tin oxide having a crystal diameter of 0.0035 μm was added with an aqueous ammonia solution adjusted to pH 11 to prepare a tin oxide sol. After mixing Suspension A and Suspension B in a predetermined ratio, it was applied to the surface of a 15 cm square tile base by spray coating, dried and baked at 850° C. for 2 hours to obtain a sample. TiO in the obtained sample₂The crystal was a rutile type. In addition, in powder X-ray diffraction, TiO₂The lattice constant of TiO was measured₂ No dissolution of tin oxide into the lattice was observed. The obtained samples were evaluated for photoactivity and abrasion resistance.

For photoactivity, an aqueous solution of potassium iodide is added dropwise to the sample surface, followed by irradiation with ultraviolet light for 30 minutes in the dropped aqueous solution of potassium iodide. evaluated. That is, according to this method, when the photoactivity of the sample surface becomes high, the oxidation-reduction reaction as shown below proceeds, so that the pH after irradiation is higher than the pH before irradiation.

Oxidation reaction: 2I^- + 2H⁺= I₂ + H₂

Reduction reaction: O₂ + 2H₂O + 4e^- = 4OH^-

In addition, the abrasion resistance was evaluated by performing perturbation abrasion using a plastic eraser, and comparing the change in appearance. Evaluation indicators , , , and × are the same as in the previous period.

65 shows the change in wear resistance with respect to the weight ratio of tin oxide in the thin film. Abrasion resistance showed good results regardless of the presence or absence of tin oxide, and it was set to (double-circle) or (circle). It is considered that sintering occurs due to processing at a high temperature of 850°C, and the particles in the film are strongly bonded to each other.

In particular, when the tin oxide content exceeded 30%, it became a double. This is the starting material TiO₂Since the crystallization ratio of the sol (crystal diameter 0.01 μm) and the tin oxide sol (crystal diameter 0.0035 μm) is 2 or more, the fine tin oxide particles are TiO₂ It was thought that it was because the filling property improved and the film|membrane was further densified by filling in the space|interval of the particle|grains.

66 shows the change in photoactivity with respect to the weight ratio of tin oxide in the thin film. Rutile-type TiO showing comparatively good antibacterial and deodorizing properties₂Samples loaded with Cu (R₃₀ΔpH of 60%) and anatase-type TiO exhibiting very good antibacterial and deodorizing properties₂ sample (R₃₀ΔpH of 97%) was also expressed as a sum. Rutile-type TiO with added tin oxide₂ΔpH is anatase-type TiO₂In the case where the weight ratio of tin oxide added is less than 10% and less than 80%, preferably 20% or more and 70% or less, the rutile-type TiO₂A value larger than ΔpH of the sample loaded with Cu was shown, and it was found that there was good photoactivity.

This is because the photocatalytic activity is not improved even when tin oxide with an average particle diameter of 0.01 µm or more is added, because the position of the conductive band is not sufficient to move upward due to the tin oxide atomization. because does not have Moreover, when it does not exceed 10 %, the lack of the ratio of the quantity of the tin oxide particle|grains that sufficient photoactivity did not generate|occur|produce is caused. On the other hand, the weak effect at 80% or more is presumed to be because the frequency of growth to an average particle diameter of 0.01 µm or more during heat treatment increases because the probability that tin oxide in the photocatalyst layer is adjacent to each other increases.

(Comparative Example 58)

TiO with a crystal diameter of 0.01 μm₂Suspension A was prepared by adding 4 to 6% by weight of the sol to an aqueous ammonia solution adjusted to pH 11. In a separate container, 10 wt% of a tin oxide sol having a crystal diameter of 0.01 µm was added to an aqueous ammonia solution adjusted to pH 11 to prepare a suspension B. After mixing the suspension A and the suspension solution B in a predetermined ratio, it was applied to the surface of a 15 cm square tile base by a spray coating method, dried and baked at 850° C. for 2 hours to obtain a sample. TiO in the obtained sample₂The crystalline form of was rutile. In addition, in powder X-ray diffraction, TiO₂The lattice constant of TiO was measured₂ No solid solution of tin oxide in the lattice was observed. This sample was evaluated for photoactivity and abrasion resistance.

67 shows the change in wear resistance with respect to the weight ratio of tin oxide in the thin film. Regardless of the presence or absence of tin oxide, the abrasion resistance showed good results and became . It is thought that sintering occurred because the treatment was performed at a high temperature of 850°C, and the particles in the film were strongly bonded to each other. However, in this case, even if the amount of tin oxide added was increased, the abrasion resistance could not be further improved. This is the TiO of the starting material.₂It is thought that this is because the particle size ratio of the sol (crystal diameter 0.01 µm) and the tin oxide sol (crystal diameter 0.01 µm) is almost the same.

68 shows the change in photoactivity with respect to the weight ratio of tin oxide in the thin film. For comparison, rutile-type TiO showing good antibacterial and deodorizing properties₂Anatase-type TiO showing ΔpH and very good antibacterial and deodorizing properties of Cu-supported samples₂ ΔpH of the sample was also shown. Rutile-type TiO with added tin oxide₂ΔpH of this time is anatase-type TiO₂ Even at ΔpH of the sample, rutile-type TiO₂The ΔpH of the sample loaded with Cu was almost not reached.

(Example 59)

TiO with a crystal diameter of 0.01 μm₂Suspension 11 was prepared by adding 4 to 6% by weight of the sol to an aqueous ammonia solution adjusted to pH 11. In a separate container, 10 wt% of a tin oxide sol having a crystal diameter of 0.0035 µm was added to an aqueous ammonia solution adjusted to pH 11 to prepare a suspension B. Suspension A and Suspension B were applied in the ratio of the base, dried, and baked at 850° C. for 2 hours to obtain a composite member. TiO in the obtained composite member₂The crystalline form of was rutile. Further, the weight ratio of tin oxide in the thin film was 60%. In addition, in powder X-ray diffraction, TiO₂The lattice constant of TiO was measured₂ No solid solution of tin oxide in the lattice was observed. After applying 5 wt% copper acetate aqueous solution to this composite member again by spray coating, drying, and then light reduction (light source is a BLB lamp of 20 W, distance from light source to sample 10 cm, irradiation time 1 minute) to prepare the sample got it Deodorizing property R for the obtained sample₃₀evaluated.

where R₃₀was obtained by the test shown below. Methyl mercaptan is used as the decomposition gas, and the sample is placed in a cylindrical container having a diameter of 26 cm x height of 21 cm, the initial concentration of methyl mercaptan is adjusted to 2 ppm. Deodorizing properties R when irradiated with light₃₀In (L), a 4W BLB fluorescent lamp was irradiated with light 8 cm away from the sample for 30 minutes, and the reduction rate of the concentration of methyl mercaptan was calculated and obtained. In addition, the deodorization characteristic R when blocking light₃₀(L) calculated and calculated|required the density|concentration decrease rate of methyl mercaptan when 30 minutes passed without light. The results are shown in (Table 26). For comparison, the samples prepared in Example 55 and Comparative Example 56 (in weight ratio of tin oxide 60%) were also tested. From (Table 26), it was found that adding Cu had the effect shown below.

[Table 26]

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(SnO₂all weight ratio of 60%)

R compared to the sample of Example 53 from (Table 26)₃₀A slight improvement was seen in (L). This is considered to be due to the electron trapping effect by Cu. In addition, compared to the samples of Example 53 and Comparative Example 54, R₃₀(L) was significantly improved. It is interpreted that the improvement of its darkening activity is due to the catalytic effect of copper.

From the above description, in the member in which the photocatalyst thin film is formed on the surface of the substrate, the TiO of the photocatalyst thin film₂ Sufficient compactness and TiO by processing at the firing temperature at which the component becomes rutile₂ The film strength can be maintained. At this time, rutile-type TiO₂ In addition, if there is tin oxide having a crystal diameter of less than 0.01 μm, the photocatalytic activity of the photocatalyst thin film can be improved.

In addition, by immobilizing at least one metal among Cu, Ag, Pt, Fe, Co, Ni, and Pd on the photocatalyst thin film, the photocatalytic activity can be further improved by electron trapping action.

As described above, the multifunctional material having antibacterial properties, antifouling agent deodorization properties, and photocatalytic function for decomposing harmful substances such as NOx according to the present invention is a wall material, tile, glass, mirror, environmental filtration device, for example, an artificial waterfall of a water circulation method. B. Stone used as a pumice stone for fountains, sanitary ware such as toilets and washbasins, MRSA, etc. It is suitable for use in hospital equipment for preventing infection in hospitals, house equipment equipment, antifungal equipment, antiviral equipment, etc.