Multifunctional material with photocatalyst function and its preparation

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a multifunctional material having a photocatalytic function that exerts functions such as a deodorizing function, an anti-bacterial (killing) function, and an antifouling function.

【0002】

[Conventional technology]

TiO as a substance that exerts a function of promoting decomposition (oxidation) by causing adsorption or desorption of oxygen molecules to organic compounds such as malodorous components by irradiating with ultraviolet rays.₂, V₂O₅, ZnO, WO₃Etc. are known, especially the crystal type is anatase type TiO₂Since particles are highly effective as photocatalysts, it has been conventionally proposed to form a photocatalyst layer on the surface of wall materials, tiles, glass (mirrors), circulation filtration devices, sanitary ware, and the like.

【0003】

As a method for forming the above photocatalyst layer, the following methods have been conventionally performed. Directly on the surface of a base material such as plastic, ceramics, resin, etc. by CVD method, sputtering method, electron beam deposition method, etc.₂A method of forming a photocatalytic layer composed of particles or the like. A method in which photocatalytic particles are kneaded with a binder and applied to the surface of a base material by a spray coating method or the like, or dip-coated by a dip coating method and then heat-treated (Japanese Patent Laid-Open No. 5-201747).

【0004】

[Problems to be Solved by the Invention]

When the CVD method, the sputtering method, the electron beam deposition method, or the like is used, the equipment becomes large-scale and the yield is poor, so that the manufacturing cost becomes high.

【0005】

On the other hand, TiO₂In order for photocatalytic particles such as particles to exert their effects as photocatalysts, it is necessary that the photocatalyst particles are irradiated with ultraviolet rays and that the photocatalyst particles come into contact with substances to be decomposed such as malodorous gas. -If the photocatalyst particles were kneaded into the binder and applied to the base material as in the 2017 No. 47 publication, many photocatalyst particles were buried in the binder layer, and the ultraviolet rays did not reach or they did not come into contact with malodorous gas. Therefore, it is not possible to exert a sufficient catalytic function.

【0006】

[Means for solving problems]

In order to solve the above problems, the following means are applied in the present invention.

【0007】

In a multifunctional material having a photocatalyst function in which a titanium oxide particle layer which is a photocatalyst is held on the surface of a base material via a binder layer, the upper layer of the titanium oxide particle layer is exposed from the binder layer so as to be in contact with the outside air. A part of the lower layer of the titanium oxide particle layer is embedded in the binder layer, and the gap between the titanium oxide particles forming the surface layer exposed from the binder layer in the titanium oxide particle layer is larger than the gap. Particles having a small particle size are filled to sinter titanium oxide particles with each other, and particles having a particle size smaller than the gap are any of tin oxide, zinc oxide, and bismuth oxide, which are larger than the gap. The particles having a small diameter are agglomerated in the neck portion between the titanium oxide particles, and the average particle size of the titanium oxide particles constituting the titanium oxide layer is less than 0.3 μm. With such a configuration, the upper layer of the photocatalyst layer is exposed, so that the catalytic function can be fully exerted, and the lower layer of the photocatalyst layer is partially embedded in the binder layer, so that the photocatalyst can be fully exerted. The particles are less likely to separate from the substrate.

【0008】

Here, the base material may be tile, sanitary ware, ceramics such as glass, resin, metal, wood, or a composite thereof.

【0009】

The photocatalytic particles include TiO.₂, ZnO, SrTiO₃, Fe₂O₃, CdS, CdSe, WO₃, FeTiO₃, GaP, GaAs, RuO₂, MoS₃, LaRhO₃, CdFeO₃, Bi₂O₃, MoS₂, In₂O₃, CdO, SnO₂Etc., and any of these may be used. In addition, TiO₂, SrTiO₃, Fe₂O₃, CdS, WO₃, MoS₃, Bi₂O₃, MoS₂, In₂O₃, CdO, etc. have a larger absolute value of the redox potential of the equivalent electron band than the absolute value of the redox potential of the conduction band, so the oxidizing power is larger than the reducing power. Has excellent antibacterial activity. In terms of raw material cost, TiO₂, Fe₂O₃, ZnO is advantageous.

【0010】

The binder layer is made of a thermoplastic material such as glaze, inorganic glass, thermoplastic resin, or solder. By forming the binder layer with a thermoplastic material in this way, the photocatalyst can be applied onto the binder layer by a simple and inexpensive method such as a spray coating method at room temperature, and the base material and the binder layer can be coated only by heat treatment. And the photocatalyst can be firmly bonded, which is advantageous in terms of manufacturing cost.

【0011】

Further, the multifunctional material having a photocatalytic function according to the present invention is configured by laminating a photocatalyst layer made of photocatalyst particles on a sheet-like binder layer made of a thermoplastic material or burying a part thereof. If such a sheet-shaped multifunctional material is attached onto existing tiles, sanitary ware, building materials, etc. and then heated, the existing tiles, etc. will have deodorant, antifouling, antibacterial, and antifungal properties. And other functions can be added.

【0012】

The average particle size of the photocatalyst particles constituting the photocatalyst layer is preferably less than 0.3 μm in order to increase the specific surface area and enhance the photocatalytic activity.

【0013】

Further, in order to enhance the wear resistance of the photocatalyst layer, it is preferable that the photocatalyst particles constituting the portion of the photocatalyst layer exposed from the binder layer are bonded to each other.

【0014】

The thickness of the photocatalyst layer is preferably 0.1 μm to 0.9 μm. If it is less than 0.1 μm, the photocatalytic particles are locally embedded in the binder layer, and a portion where the catalytic activity cannot be exhibited is generated on the surface of the multifunctional material, and bacteria are retained in the portion, so that the antibacterial property is particularly deteriorated. .. If it exceeds 0.9 μm, the thickness varies widely, and it becomes difficult to remove stains when stains adhere to the sample. Here, the thickness of the photocatalyst layer includes the portion from the outermost surface to the portion embedded in the lower layer of the binder layer, and the thickness of each unevenness is averaged.

【0015】

Here, a design effect can be obtained by changing the thickness of the photocatalyst layer. That is, if the thickness is set to 0.2 μm or more and less than 0.4 μm, an iris-colored pattern can be formed by the interference action of light with respect to the film thickness portion of the photocatalyst layer, and the background color, pattern or them of the base material in appearance. If it is desired to form only the bonds of the above, the photocatalyst layer film thickness portion may be prepared 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 the light interference action occurs. Such a method can be applied to a wide range such as tiles, wash basins, bathtubs, large / urinals, sinks, and countertops.

【0016】

As a method of binding the photocatalyst particles constituting the portion of the photocatalyst layer exposed from the binder layer to each other, for example, the gaps between the photocatalyst particles are filled with particles having a particle size smaller than the gaps. When only the photocatalytic particles are bonded to each other, there is no choice but to adsorb or sinter the photocatalytic particles. However, when utilizing the sintering action between photocatalyst particles, it is necessary to sinter at a considerably high temperature, while in the case of adsorption, the specific surface area of the photocatalyst particles must be made very large and the filling property must be improved. The method is limited in order to produce a multifunctional material having sufficient catalytic activity and abrasion resistance, such as consuming only the amount of the photocatalytic particles adsorbed on the active site. Further, if particles larger than the gaps between the photocatalyst particles are used to strengthen the bonding of the photocatalyst particles, not only a sufficient bonding force cannot be obtained, but also the photocatalyst particles exposed on the surface of the multifunctional material are partially covered. As a result, there is a portion on the surface of the multifunctional material that cannot exhibit catalytic activity, and bacteria stay in that portion, so that the antibacterial property is significantly deteriorated. The gaps between the photocatalyst particles referred to here are the neck portion between the photocatalyst particles 3b and 3b as shown in FIG. 3 (a) and the gap between the photocatalyst particles 3b and 3b as shown in FIG. 3 (b). Refers to both pores. Therefore, the particles 3c having a particle size smaller than the gaps between the photocatalyst particles referred to here refer to particles smaller than the gaps between the neck portion between the photocatalyst particles and the pores between the photocatalyst particles.

【0017】

Further, as the small particles filled in the gaps between the photocatalyst particles, the material is basically not limited, but those having excellent adsorption power are preferable. A material with extremely weak adsorption capacity cannot achieve the purpose of binding the photocatalytic particles to each other, and a material with extremely strong adsorption capacity covers the active site on the surface of the photocatalytic particles rather than being inserted into the gap. This is because the probability increases. From this point of view, metals or oxides such as Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, and Ni are preferable as the material of the particles filled in the gaps of the photocatalytic particles. Zeolites, activated carbon, clay and the like used as adsorption carriers are not preferable. Among the above metals or oxides, tin oxide is preferable in that it has an appropriate adsorption ability, and metals or oxides such as Ag and Cu have unique antibacterial properties other than binding the photocatalytic particles to each other. Since it has deodorant properties, it is preferable in that it also has a function of assisting the action of a photocatalyst in an application utilizing this function, particularly when there is no irradiation with light.

【0018】

Further, the average particle size of the particles filled in the gaps between the photocatalyst particles is preferably 4/5 or less of the average particle size of the photocatalyst particles. In the current production method, the particles that fill the gaps between the photocatalyst particles adhere not only to the gaps between the photocatalyst particles but also to some extent on the photocatalyst particles. When the particle size of the particles that fill the gap exceeds 4/5 of the average particle size of the photocatalyst particles, the probability of adhesion to the surface of the photocatalyst particles is higher than that of the gaps of the photocatalyst particles, and the bond strength between the photocatalyst particles decreases. To do. In addition, if the particles that fill the gaps are larger than the photocatalytic particles, the photocatalytic particles will be partially covered, and there will be a portion on the surface of the multifunctional material that cannot exhibit catalytic activity, so that bacteria can stay in that portion. Therefore, there is a possibility that the antibacterial property will be significantly deteriorated.

【0019】

Further, it is preferable that the average particle size of the particles filled in the gaps between the photocatalyst particles is less than 0.008 μm because the specific surface area is increased and an appropriate adsorption force can be obtained.

【0020】

The amount of the particles filled in the gaps between the photocatalyst particles with respect to the photocatalyst particles is preferably 10% or more and 60% or less in terms of molar ratio. When the photocatalyst layer is fixed to the substrate via a binder by heat treatment in a temperature range where the photocatalyst particles do not sinter, if the amount of particles filling the gap is too small, the photocatalyst particles do not bond firmly with each other. On the other hand, if the amount of particles that fill the gap is too large, the amount of particles that cover the photocatalytic particles will be large, and there will be a portion on the surface of the multifunctional material that cannot exhibit catalytic activity, and bacteria will be able to stay in that portion. In particular, the above range is preferable because the antibacterial property is remarkably deteriorated.

【0021】

Further, as a substance constituting the particles filled in the gaps of the photocatalyst particles, a substance having a vapor pressure higher than the vapor pressure of the substance constituting the photocatalyst particles is selected, and the particles filled in the gaps of the photocatalyst particles are used as a photocatalyst. It is preferable to agglomerate in the neck portion between the particles. This is because, in order to obtain stronger bonds between the photocatalyst particles and increase the peel strength of the photocatalyst layer, it is better to sinter as well as fill the particles. Further, if such a substance having a high vapor pressure is selected for the particles that fill the gap, it also functions as a sintering aid and can lower the sintering temperature. Examples of such a substance having a high vapor pressure include tin oxide, bismuth oxide, zinc oxide and the like, but tin oxide is preferable from the viewpoint of safety.

【0022】

The thickness of the layer containing the particles filled in the gaps between the photocatalyst particles is preferably 0.1 μm or more. If the thickness of this layer is less than 0.1 μm, photocatalytic particles (and particles that fill the gaps depending on the manufacturing method) are locally embedded in the binder layer, resulting in a portion on the surface of the multifunctional material that cannot exhibit catalytic activity. Since the bacteria can stay in the water, the antibacterial property is significantly deteriorated. Here, the thickness of the layer containing the particles filled in the gaps between the photocatalyst particles includes the portion from the outermost surface to the portion embedded in the lower layer of the binder, and the thickness of each unevenness is averaged.

【0023】

Here, a design effect can be obtained by changing the thickness of the photocatalyst layer. That is, if the thickness is set to 0.2 μm or more and less than 0.4 μm, an iris color pattern can be formed by the interference action of light with respect to the photocatalyst layer film thickness portion. If there is no coloring by the particles that fill the gaps, and if you want only the background color, pattern, or their bond of the base material in appearance, 0.1 μm or more and less than 0.2 μm or 0.4 μm excluding the part that causes the light interference effect. The photocatalyst layer film thickness portion may be prepared to be less than 1 μm or more. Such a method can be applied to a wide range such as tiles, wash basins, bathtubs, large / urinals, sinks, and countertops.

【0024】

Further, the depth of embedding of the photocatalyst particles constituting the lowermost layer of the photocatalyst layer in the binder layer is 1/2 or more of the particle size, and the binder layer is less than the thickness of the layer containing the particles that fill the gap with the photocatalyst particles. It is preferable that it is buried inside. By embedding the photocatalyst particles in the binder layer at least 1/2 of the particle size, the bottom layer of the photocatalyst particle layer and the binder layer are firmly bonded to each other, and the thickness of the layer containing the photocatalyst particles and the particles filling the gap is equal to or more than the thickness of the layer. If it is buried, there will be a part where the photocatalytic particles are not exposed on the outermost surface, and since that part cannot exert catalytic activity on the surface of the multifunctional material, bacteria can stay in that part, so it is particularly antibacterial. Will get worse significantly.

【0025】

In addition, the base material can be used as tiles and stone materials used as paving stones for water circulation type artificial waterfalls and fountains in parks and department stores. By using a multifunctional material having a photocatalytic function for such an application, it is possible to decompose organic filth accumulated in water by using light including artificial lighting or natural light ultraviolet rays along with circulation. In addition, it is possible to prevent the growth of bacteria, molds, etc., the outbreak of algae, and the accompanying odor of water, and it is possible to create a cleaner environment.

【0026】

Further, the multifunctional material having a photocatalytic function according to the present invention is used as a bacterial infection prevention device in a hospital, but can also be used as an antifungal and antiviral device because it can decompose other organic substances.

【0027】

Further, in the method for producing a multifunctional material having a photocatalytic function according to the present invention, a binder layer made of a thermoplastic material is formed on a base material such as ceramic, resin or metal, and then a photocatalyst is formed on the binder layer. A photocatalyst layer composed of particles is formed, and then the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then solidified. Here, if the viscosity of the binder layer is too high, the binder layer and the photocatalyst particles are not sufficiently bonded, and conversely, if the viscosity is too low, the photocatalyst particles are buried in the binder layer, and when it occurs locally, bacteria grow. Since the binder layer becomes retained, the antibacterial property is significantly deteriorated. Therefore, the degree of softening of the binder layer is determined in consideration of these factors.

【0028】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention is to form a photocatalytic layer made of photocatalytic particles on a sheet-shaped binder layer made of a thermoplastic material, and the sheet-shaped binder layer is made of ceramic. It is placed or affixed on a substrate made of resin or metal, and then the binder layer is softened, a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then solidified. According to this method, functions such as deodorant property, antifouling property, antibacterial property, and antifungal property can be added to existing tiles, sanitary ware, building materials, and the like later.

【0029】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material, in which a binder layer made of a thermoplastic material is formed on a base material such as ceramic, resin or metal, and then photocatalytic particles and the above-mentioned photocatalytic particles are formed on the binder layer. A mixture of particles having a small particle size mixed in a sol or a precursor state is applied to form a photocatalyst layer, and then the binder layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the binder layer. Then solidify. According to this method, the photocatalyst layer is formed by applying a mixture of the particles that fill the gap and the photocatalyst particles in the state of a sol or a precursor in advance, so that the photocatalyst particles and the particles that fill the gap are mixed. Useful for controlling the ratio.

【0030】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material, in which a mixture of photocatalytic particles and particles having a small particle size in the form of a sol or a precursor is applied onto a sheet-like binder layer made of a thermoplastic material. The photocatalyst layer is formed, and the sheet-shaped binder layer on which the photocatalyst layer is formed is placed or attached to a base material such as ceramic, resin, or metal, and then the binder layer is softened to soften the photocatalyst layer. A part of the lower layer is embedded in the binder layer and then solidified.

【0031】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material, in which a binder layer made of a thermoplastic material is formed on a base material such as ceramic, resin or metal, and then a photocatalytic particle is formed on the binder layer. A photocatalyst layer is formed, after which the binder layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the binder layer, then the binder layer is solidified, and the photocatalyst layer further contains particles having a small particle size. Is applied and heat-treated to immobilize the particles having a small particle size on the photocatalytic particles. This method can be carried out relatively easily when the particles filling the gaps are oxides, and when a relatively porous photocatalyst layer is prepared, a large amount of particles filling the gaps can be attached. ..

【0032】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material, in which a photocatalyst layer made of photocatalyst particles is formed on a sheet-like binder layer made of a thermoplastic material, and then the sheet-like binder layer on which the photocatalyst layer is formed is made of ceramic. , Resin or metal, etc., and then the binder layer is softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, and then the binder layer is solidified. A solution containing the particles having a small particle size is applied to the photocatalyst layer and heat-treated to immobilize the particles having a small particle size on the photocatalyst particles.

【0033】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with metal particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material having a structure, in which a binder layer made of a thermoplastic material is formed on a base material such as ceramic, resin or metal, and then a binder layer made of a thermoplastic material is formed on the binder layer from photocatalytic particles. The photocatalyst layer is formed, and then the binder layer is softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, and then the binder layer is solidified. A method for producing a multifunctional material having a photocatalytic function, which comprises applying a solution containing ions and then irradiating light containing ultraviolet rays to reduce metal ions and immobilize them on photocatalytic particles. This method can be carried out relatively easily when the particles filling the gap are metal, and the metal can be fixed in an extremely short time (several minutes). The lamp used for ultraviolet irradiation may be an ultraviolet lamp, a BLB lamp, a xenon mercury lamp, or a fluorescent lamp.

【0034】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with metal particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. This method is a method for producing a multifunctional material having a photocatalyst layer, in which 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 on which the photocatalyst layer is formed is formed. It is placed or affixed on a substrate made of ceramic, resin, metal, etc., after which the binder layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified. Further, a solution containing ions of the metal particles having a small particle size is applied to the photocatalyst layer, and then light containing ultraviolet rays is irradiated to reduce the metal ions and immobilize them on the photocatalyst particles.

【0035】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with metal particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material having a structure, in which a binder layer made of a thermoplastic material is formed on a base material such as ceramic, resin or metal, and then a binder layer made of a thermoplastic material is formed on the binder layer from photocatalytic particles. A photocatalyst layer is formed, and a solution containing ions of metal particles having a small particle size is applied to the photocatalyst layer, and then light containing ultraviolet rays is irradiated to reduce the metal ions and immobilize them on the photocatalyst particles. The binder layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified. According to this method, the heat treatment step can be completed only once, so that the productivity is improved.

【0036】

Further, another method for producing a multifunctional material having a photocatalytic function according to the present invention has a photocatalytic function in which the gaps between the photocatalytic particles are filled with metal particles having a particle size smaller than the gaps and the photocatalytic particles are bonded to each other. A method for producing a multifunctional material having a photocatalyst, in which a photocatalyst layer made of photocatalyst particles is formed on a sheet-like binder layer made of a thermoplastic material, and the photocatalyst layer is formed with metal particles having a small particle size. A solution containing ions is applied, and then light containing ultraviolet rays is irradiated to reduce metal ions to be immobilized on photocatalyst particles, and a sheet-like binder layer on which a photocatalyst layer is formed is formed of a base made of ceramic, resin, metal, or the like. It is placed or affixed on the material, after which the binder layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and then the binder layer is solidified.

【0037】

The photocatalyst particles are ZnO, and the metal particles filled in the gaps between the photocatalyst particles are Ag or Ag.₂It can be O. Where Ag or Ag₂O particles not only strengthen the bonds between ZnO particles, which are photocatalysts, but also enhance the photocatalytic effect of ZnO, and also have antibacterial and deodorant effects by themselves. Further, by selecting ZnO as a photocatalyst, coloring due to Ag ions can be eliminated, and the background color and pattern of the base material or the design effect due to their combination can be improved.

【0038】

Further, a solution containing salts that form an insoluble, colorless or white salt with the metal ions filled in the gaps between the photocatalyst particles is brought into contact with the photocatalyst layer, and then light containing ultraviolet rays is irradiated. You may do so. By doing this, ZnO and Ag or Ag₂Even if it does not depend on the combination of O, it is possible to eliminate the coloring caused by the particles that fill the gap, and the background color of the base material. The design effect of the patterns or their combination can be improved.

【0039】

In addition, the photocatalytic particles are TiO₂The heat treatment temperature for softening the binder layer may be 800 ° C. or higher and 1000 ° C. or lower. TiO above 800 ° C₂Since a neck part is formed between the particles by initial sintering, TiO₂The bond strength between the particles improves, but when the temperature exceeds 1000 ° C, the process shifts to the medium-term sintering process, and TiO₂Since the volume shrinkage of the photocatalyst layer due to the solid phase sintering is remarkable, cracks are likely to occur.

【0040】

In addition, the photocatalytic particles are TiO₂Let Ag be the metal particles filled in the gaps between the photocatalytic particles, and KI, KCl, FeCl be a solution containing salts that form insoluble, colorless or white salts with the ions of this metal.₃It may be an aqueous solution of a halide such as. Since Ag forms an insoluble, colorless or white salt such as AgI or AgCl with an alkali halide, it is possible to improve the design by the background color and pattern of the base material or their combination.

【0041】

Further, the binder layer is selected to have a softening temperature lower than the softening temperature of the base material, and is in a range of more than 20 ° C and less than 320 ° C, preferably 40 ° C or more and 300 ° C or more, which is higher than the softening temperature of the binder layer. Heat treatment is performed at an ambient temperature within the range of ° C or less and lower than the softening temperature of the substrate. If the heat treatment temperature is lower than the temperature 20 ° C higher than the softening temperature of the binder layer, the viscosity of the binder layer is too high and the binder layer and the photocatalyst particles are not sufficiently bonded, and conversely, the temperature is higher than the softening temperature of the binder layer. If the heat treatment temperature is higher than the temperature higher than 320 ° C, the viscosity of the binder layer is too low and the photocatalyst particles are buried in the binder layer, and when it occurs locally, the bacteria stay there, resulting in antibacterial properties. By falling.

【0042】

When a dispersion step is provided as a pre-step of the step of applying the photocatalyst particles on the binder layer, the dispersant for dispersing the sol or precursor to be the photocatalyst particles in this dispersion step in the solution may be used. It is preferable to use only the components that vaporize at a temperature lower than the heat treatment temperature for softening the binder layer. In the prior art, the reason why there was no deodorant property at less than 320 ° C was that TiO in the dispersion process.₂Since the dispersant adhering to the particle surface remained without being sufficiently vaporized and evaporated, TiO₂This is because the particle surface was not sufficiently exposed on the outermost surface of the base material, and the photocatalytic function became insufficient. As the dispersant that vaporizes at a low temperature, an organic dispersant having a molecular weight of 10,000 or less and a phosphoric acid-based dispersant are preferable.

【0043】

Further, when the specific gravity of the photocatalyst particles is δt and the specific gravity of the binder layer is δb, it is preferable that 0 δt-δb 3.0. If the specific gravity difference is too small, the photocatalyst particles are not sufficiently embedded in the binder layer and the binder layer and the photocatalyst particles are not sufficiently bonded. If the specific gravity difference is too large, the photocatalyst particles are buried in the binder layer. This is because when it occurs locally, bacteria stay on the bottom and the antibacterial property is lowered. As an application method of this method, even when δt-δb> 3.0 must be set, a second binder layer having 0 δt-δb 3.0 may be interposed between the binder layer and the photocatalyst particles. .. Further, when δt-δb <0, the same effect as increasing the specific gravity difference δt-δb can be obtained by applying pressure during the heat treatment. Therefore, the same effect as when 0 δt-δb 3.0 can be obtained by the HIP treatment and the hot press treatment.

【0044】

[Action]

Of the photocatalyst particles constituting the photocatalyst layer, the photocatalyst particles forming the lower layer on the binder layer side are held in a state of being partially buried in the binder layer, and the photocatalyst particles constituting the surface layer in contact with the outside air of the photocatalyst layer are substantially. Since the particles are bonded to each other with the surface exposed to the outside, the photocatalytic effect is sufficiently exhibited.

【0045】

[Example]

Examples of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a diagram illustrating a method for manufacturing a multifunctional material having a photocatalytic function according to the present invention, and FIG. 2 is an enlarged view of a main part of FIG. 1 (d). As shown in (a), the base material 1 is prepared. As the base material 1, ceramic, resin, metal, glass, wood, or the like can be considered.

【0046】

Then, as shown in FIG. 6B, the binder layer 2 is formed on the surface of the base material 1. As the binder layer 2, a material whose softening temperature is lower than the softening temperature of the base material 1 is selected. For example, when the base material 1 is tile, enamel or ceramic, the glaze layer or the printing layer can be used as it is as the binder layer 2.

【0047】

Then, as shown in FIG. 3C, TiO is placed on the binder layer 2.₂A photocatalyst layer 3 composed of photocatalyst particles such as particles is formed. At this time, the photocatalyst layer 3 may be placed on the binder layer 2 with a binding force that does not fall off from the binder layer 2 during the subsequent firing.

【0048】

Alternatively, before forming the binder layer 2 on the surface of the base material 1, the photocatalyst layer 3 is formed on the binder layer 2 as shown in the figure (b'), and the binder layer 2 is placed on the base material 1. It may be placed.

【0049】

After that, the heat treatment is performed at an atmospheric temperature higher than the softening temperature of the binder layer 2 in a range of more than 20 ° C and less than 320 ° C and lower than the softening temperature of the base material 1 to obtain the figures (d) and FIGS. As shown in 2, a part of the photocatalyst particles 3a constituting the lower layer on the binder layer side of the photocatalyst layer 3 settles in the molten binder layer and the binder layer solidifies, so that a part of the photocatalyst particles 3a is contained in the binder layer. It is buried and held firmly. Further, among the photocatalyst layers 3, some of the photocatalyst particles 3b constituting the surface layer in contact with the outside air are bonded to each other by intermolecular force between them or sintering by firing, and other parts are bonded as shown in FIG. 3A. Then, as shown in Fig. 3 (b), they are separated. That is, the surface of the photocatalyst particles 3b is substantially exposed to the outside in the surface layer.

【0050】

Here, the reason why the heat treatment temperature was raised in the range of more than 20 ° C and less than 320 ° C than the softening temperature of the binder layer 2 is that if it is less than 20 ° C, it takes time to soften the binder layer and the photocatalyst. If the particles 3a are not sufficiently retained, while the temperature exceeds 320 ° C, the photocatalytic particles are buried in the binder layer due to rapid melting of the binder layer, irregular surfaces are generated, and breaks and pinholes are generated. Therefore, it is preferably 40 ° C or more and 300 ° C or less.

【0051】

When the specific gravity of the photocatalyst particles is δt and the specific gravity of the binder layer 2 is δb, the relationship is 0 δt-δb 3.0, preferably 0.5 δt-δb 2.0. This is because if the difference in specific gravity between the photocatalyst particles and the binder layer is too small, the vertical movement speed of the photocatalyst particles in the binder layer becomes slow when the binder layer is melted, and the photocatalyst particles are easily peeled off after firing. This is because if the difference in specific gravity between the photocatalyst particles and the binder layer is too large, the vertical movement speed of the photocatalyst particles increases, and most of the photocatalyst particles are buried in the binder layer. Further, between the gaps of the photocatalyst particles constituting the portion exposed from the binder layer 2, specifically, the neck portion of the photocatalyst particles 3b shown in FIG. 3 (a), or between the photocatalyst particles 3b shown in FIG. 3 (b). Particles 3c (Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni and other metals or oxides) having a particle size smaller than the gap are filled to bond the photocatalytic particles 3b to each other. You may.

【0052】

Specific examples are given below. (Reference example 1) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-Na / K₂A binder layer consisting of O-frit is formed by a spray coating method, dried, and then 15% TiO.₂Aqueous solution of sol is applied by spray coating method, and TiO with a film thickness of 0.8 μm₂Form a layer, then a binder layer and TiO₂The base material on which the layers were laminated was heated and fired at different atmospheric temperatures with a roller hers kiln for each example, and then cooled and solidified to obtain a multifunctional material. Here TiO₂The sol aqueous solution is, for example, TiCl.₄Anatase-type TiO obtained by hydrolyzing in an autoclave under hydrothermal conditions in the range of 100 to 200 ° C and having a crystallite diameter of about 0.007 to 0.2 μm.₂Is dispersed in a sol state in an acidic aqueous solution such as nitric acid or hydrochloric acid or a basic aqueous solution such as ammonia in an amount of several% to several tens of percent. Triethanolamine and trimethylol are used as surface treatment agents to improve dispersibility. Amine organic acid salt, pentaerythrit, trimethylolpropane, etc. are added in the range of 0.5% or less. In addition, TiO₂The particle size of the sol was calculated by image processing of SEM observation, and the crystallite diameter was calculated from the integrated width of powder X-ray diffraction. The coating method was a spray coating method, but it is expected that similar results can be obtained with a dip coating method and a spin coating method. The obtained multifunctional material was evaluated for antibacterial property and wear resistance. For antibacterial properties, the bactericidal effect on Escherichia coli W3110 strain was tested. In advance, 0.15 ml (1 to 5 x 104 CFU) of bacterial solution was dropped on the outermost surface of a multifunctional material sterilized with 70% ethanol, placed on a glass plate (10 x 10 cm), and brought into close contact with the outermost surface of the substrate. did. After irradiating with a white light (3500 lux) for 30 minutes, the bacterial solution of the irradiated sample and the sample maintained under shading conditions was wiped with sterile gauze and collected in 10 ml of physiological saline, and the survival rate of the bacterial was determined and evaluated. It was used as an index. For wear resistance, sliding wear was performed using a plastic eraser, and changes in appearance were compared and evaluated. The following (Table 1) shows ceramic tiles as the base material and SiO as the binder.₂-Al₂O₃-Na / K₂Shows changes in antibacterial and wear resistance with changes in firing temperature when using O-frit.

【0053】

[table 1]

【0054】

Here, SiO used as a binder₂-Al₂O₃-Na / K₂The specific gravity of the O-frit was 2.4, the film thickness when applied was 200 μm, and the softening temperature was 680 ° C. Also, the TiO obtained in (Table 1)₂Nos. 1 to 3 were anatase type and had a specific gravity of 3.9, and Nos. 4 and 5 were rutile type and had a specific gravity of 4.2.

【0055】

In (Table 1), the firing temperature of No. 1 was only 20 ° C higher than the softening temperature of the binder, and the viscosity of the binder was not sufficiently low, so that the anatase-type TiO constituting the lowest layer of the photocatalyst layer was formed.₂The particles were not sufficiently embedded in the binder layer, so that they were scratched and peeled off after sliding 5 to 10 times in the abrasion resistance test. Regarding antibacterial properties, it is anatase type with excellent photocatalytic activity, and TiO at 300 ° C or higher.₂According to TG-DTA observation of the sol, the organic components are almost decomposed and vaporized, and TiO₂It is understood that the dispersant such as the surface treatment agent adhering to the surface is naturalized, but the firing temperature is 700 ° C, which is much higher than that, so the value is ++. ..

【0056】

Nos. 3 to 5 are cases where the firing temperature is 800 ° C or more and 1000 ° C or less, but the durability is extremely excellent without any change even in the sliding test of 40 times or more. The cause of this is surface TiO₂It is conceivable that a neck portion is formed due to the initial firing of the particles. When treated at 1100 ° C, TiO on the surface of the multifunctional material taken out from the roller hers kiln after cooling and solidifying.₂There were cracks in the layer. This is TiO₂Judging from the TMA measurement of the test piece, TiO₂It is considered that this is due to medium-term sintering with remarkable volume shrinkage of the particles.

【0057】

In Nos. 4 and 5, the antibacterial properties were all worse. There are two possible causes for this. One is TiO₂The 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 more than 300 ° C, and the viscosity of the binder becomes too low to form the photocatalytic layer.₂It is probable that the particles have been embedded in the binder layer. Here, TiO₂It cannot be considered that the cause is only the phase transition of the particles to the rutile type. Rutile type TiO₂Also in, anatase type TiO₂This is because there is some photocatalytic activity, although it is inferior to. For example, TiO directly on a porous alumina substrate₂The sol was spray-coated, calcined at 950 ° C, and then cooled and solidified, and the antibacterial property of the sample was +. Therefore, the firing temperature is higher than the softening temperature of the binder by more than 300 ° C, and the viscosity of the binder becomes too low, so that the TiO forming the photocatalyst layer is formed.₂It is understood that the fact that the particles are buried in the binder layer also contributes to this.

【0058】

In addition, by elemental analysis of Ti and Si (main component of the binder) by EPMA in the cross-sectional direction of the sample, a layer in which Ti and Si were mixed was observed, and TiO, which is a photocatalytic particle, was observed.₂Was confirmed to be buried.

【0059】

Reference example 1 above, that is, at least the photocatalyst is TiO₂, The binder layer is SiO₂-Al₂O₃-Na / K₂At the time of O frit, the following was confirmed. When a multifunctional material is manufactured under conditions where the firing temperature is higher than the softening temperature of the binder by more than 20 ° C and not higher than 300 ° C, a multifunctional material with good antibacterial and abrasion resistance is manufactured. it can. The cause is that the viscosity of the binder is TiO in the above temperature range.₂Is considered to be because the value is adjusted so that it can be appropriately embedded in the binder layer. The multifunctional material produced in₂Embedding of particles in the binder layer was confirmed. When the firing temperature was 800 ° C or higher and 1000 ° C or lower, the wear resistance did not change even in the sliding test of 40 times or more, and was extremely excellent. TiO₂It is considered that this is due to the strong bond that accompanies the formation of the neck between the particles.

【0060】

(Reference example 2) On the surface of a 100 x 100 x 5 alumina base material (alumina purity 96%), SiO₂-Al₂O₃-After forming a binder layer consisting of PbO frit by spray coating method and drying, 15% TiO₂An aqueous sol solution (same as Reference Example 1) is applied by a spray coating method, and a TiO with a film thickness of 0.8 μm is applied.₂Form a layer, then a binder layer and TiO₂The base material on which the layers were laminated was heated and fired at different atmospheric temperatures with a roller hers kiln for each example, and then cooled and solidified to obtain a multifunctional material.

【0061】

The following (Table 2) shows alumina as the base material and SiO as the binder.₂-Al₂O₃-Shows changes in antibacterial and wear resistance with changes in firing temperature when using PbO frit.

【0062】

[Table 2]

【0063】

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 TiO₂The crystal types of were all anatase types.

【0064】

In the abrasion resistance test of (Table 2), No. 6 was scratched and peeled off after sliding 10 times or less, but No. 7 and 8 were not scratched even after sliding 10 times or more. Furthermore, No. 9 and 10 gave good results that no scratches were formed even after sliding 40 times or more.

【0065】

No. 9 and 10 did not get scratched even after sliding 40 times or more because the firing temperature was 800 ° C or more, so TiO₂Neck is created between particles, TiO₂It is probable that the particles were firmly bonded to each other. No. 6 was scratched and peeled off after sliding 10 times or less because the firing temperature was only 20 ° C higher than the softening temperature of the binder and the viscosity of the binder was not sufficiently low. , Anatase-type TiO that constitutes the bottom layer of the photocatalyst layer₂It is considered that the particles were not sufficiently embedded in the binder layer. On the other hand, in Nos. 7 and 8, the reason why the binder did not get scratched even after sliding 10 times or more was that the difference between the firing temperature and the softening temperature of the binder, although it did not reach the temperature at which the neck was formed, was the binder. Viscosity TiO₂Is considered to be because the value was adjusted so that it could be appropriately embedded in the binder layer. On the other hand, in the antibacterial property test of (Table 2), No. 6 to 9 gave good results of +++ or ++, but No. 10 became +. This is because the firing temperature is 320 ° C higher than the softening temperature of the binder, and the viscosity of the binder becomes too low, which constitutes the photocatalytic layer.₂It is probable that the particles were buried in the binder layer.

【0066】

(Reference example 3) SiO₂-Al₂O₃-After melting and solidifying the BaO frit in the mold, it is processed to make a 100 x 100 x 1 glass sheet, and 15% TiO on it.₂An aqueous sol solution (same as Reference Example 1) is applied by a spray coating method, and a TiO with a film thickness of 0.8 μm is applied.₂Formed a layer. Then, the glass sheet was placed on an alumina base material (100 × 100 × 5), heated and fired in a siliconite furnace at different atmospheric temperatures for each reference example, and then cooled and solidified to obtain a multifunctional material.

【0067】

The following (Table 3) shows the changes in antibacterial properties and wear resistance with changes in the firing temperature of the above multifunctional materials.

【0068】

[Table 3]

【0069】

Here, SiO used as a binder₂-Al₂O₃-BaO frit softening temperature is 620 ° C, specific gravity is 2.8, TiO on multifunctional material₂The crystal types of No. 11 to 13 were anatase type and No. 14 was rutile type.

【0070】

In the abrasion resistance test of (Table 3), No. 11 was scratched and peeled off after sliding 10 times or less, but No. 12 was not scratched even after sliding 10 times or more, and further. , Nos. 13 and 14 gave good results that no scratches were formed even after sliding 40 times or more.

【0071】

No. 13 and 14 did not get scratched even after sliding 40 times or more because the firing temperature was 800 ° C or more, so TiO₂Neck is created between particles, TiO₂It is probable that the particles were firmly bonded to each other. No. 11 was scratched and peeled off after sliding 10 times or less because the firing temperature was only 20 ° C higher than the softening temperature of the binder and the viscosity of the binder was not sufficiently low. , Anatase-type TiO that constitutes the bottom layer of the photocatalyst layer₂It is considered that the particles were not sufficiently embedded in the binder layer. On the other hand, in No. 12, the reason why the binder was not scratched even after sliding 10 times or more was that the difference between the firing temperature and the softening temperature of the binder, although it did not reach the temperature at which the neck was formed, caused the viscosity of the binder. TiO₂Is considered to be because the value was adjusted so that it could be appropriately embedded in the binder layer. On the other hand, in the antibacterial property test of (Table 3), No. 11 to 13 gave good results of +++ or ++, but No. 14 became-. This is TiO₂Is a rutile type, the firing temperature is 320 ° C higher than the softening temperature of the binder, and the viscosity of the binder becomes too low, so that the TiO that constitutes the photocatalyst layer is formed.₂It is considered that there are two causes that the particles are buried in the binder layer.

【0072】

From the above, TiO is used as a binder in advance.₂In the method of applying the particles, attaching them to the base material, and firing them to obtain a multifunctional material, the binder is applied to the surface of the base material, and then TiO.₂It was confirmed that the same effect as the method of applying particles to obtain a multifunctional material can be obtained.

【0073】

(Reference example 4) After applying an acrylic resin binder to the surface of a base material made of 100 x 100 x 5 polyimide resin, 15% TiO₂Aqueous solution of sol is applied by spray coating method, and TiO with a film thickness of 0.8 μm₂Form a layer, then a binder layer and TiO₂The base material on which the layers were laminated was fired in a nichrome furnace at 150 ° C. to obtain a multifunctional material.

【0074】

The following (Table 4) shows the changes in antibacterial properties and wear resistance with changes in the firing temperature of the above multifunctional materials.

【0075】

[Table 4]

【0076】

In (Table 4), 15% TiO₂The method for preparing the aqueous sol solution was changed as follows. No.15: 15% TiO used in Reference Example 1₂The aqueous sol solution was used as it was. No.16: TiCl₄The aqueous solution was hydrolyzed in an autoclave at 110 to 150 ° C., the product was adjusted to pH 0.8 with nitric acid, dispersed without using a surface modifier, and then the agglomerates were removed. In this case, spray coating was performed immediately after removing the agglomerates.

【0077】

Here, TiO₂The specific gravity of is 3.9, the crystal type is anatase, the specific gravity of acrylic resin is 0.9, and the temperature at which it becomes viscous corresponding to the glass softening point is 70 ° C.

【0078】

With regard to wear resistance, no scratches were found even under any of the conditions No. 15 and 16 and even after sliding 10 times or more. This means that the range of the difference between the firing temperature and the softening temperature of the binder makes the viscosity of the binder TiO.₂It is probable that was a value that could be adjusted to a value that could be appropriately embedded in the binder layer.

【0079】

On the other hand, regarding the antibacterial property test, No. 15 became-, but No. 16 obtained a good result of ++, so it is possible to manufacture a multifunctional material with antibacterial properties even at less than 30 ° C. I found that. This difference is the No. 15 TiO in DTA-TG.₂In the sol, there is a component that decomposes and evaporates at 200 to 350 ° C, but since it is not observed in No. 16, TiO₂It is considered that the cause is the presence or absence of organic components that cover the area. Here, the difference in specific gravity between anatase and acrylic resin is 3, but if this difference is used, the TiO that constitutes the photocatalyst layer₂It was also confirmed that the particles had good antibacterial properties without being embedded in the binder layer.

【0080】

(Reference example 5) A binder layer consisting of frit or the like having a different specific gravity is formed on the surface of a 100 × 100 × 5 alumina base material by a spray coating method, and after drying, 15% TiO.₂TiO with a film thickness of 0.8 μm by spray coating the sol aqueous solution₂Form a layer, then a binder layer and TiO₂A multi-functional material was obtained by heating and firing the base material on which the above layers were laminated with a roller hers kiln at an atmospheric temperature of 750 ° C and then cooling and solidifying.

【0081】

The following (Table 5) shows the changes in antibacterial properties and wear resistance with changes in the firing temperature of the above multifunctional materials.

【0082】

[Table 5]

【0083】

Regarding the antibacterial property test, good results were obtained with +++ in all of Nos. 17 to 20. In either case, the firing temperature is higher than the softening temperature of the binder in the range of 30 ° C or more and 300 ° C or less, and the range of the difference between the firing temperature and the softening temperature of the binder determines the viscosity of the binder.₂It is probable that the value was adjusted to a value that could be appropriately embedded in the binder layer.

【0084】

Regarding wear resistance, No. 17 was scratched and peeled off after sliding 5 times or less, but No. 18 to 20 were not scratched even after sliding 10 times or more. As for the cause, unlike the others in No. 17, the specific gravity of the binder is TiO.₂Anatase-type TiO which constitutes the lowest layer of the photocatalytic layer because it is larger than the specific gravity of₂It is considered that the particles were not sufficiently embedded in the binder layer. Therefore, the wear resistance of multifunctional materials is determined by TiO.₂The specific gravity of the binder and the binder also has an effect, and the specific gravity of the binder is TiO.₂It turned out that it worsens when it is larger than the specific gravity of.

【0085】

(Example 6) SiO on the surface of 150 square ceramic tile base material₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂Sol and SnO₂An aqueous solution in which the sol was mixed and stirred was applied by a spray coating method, and then calcined at 750 ° C. to be cooled and solidified to obtain a multifunctional material. TiO₂Sol concentration is 4 ~ 6wt% and NH₃Adjusted to PH11 with an aqueous solution, TiO₂The crystallite diameter of the particles is 0.01 μm, and SnO₂The crystallite diameter of the particles is 0.0035 μm.

【0086】

About the multifunctional material produced in this way TiO₂SnO against₂The results of antibacterial and abrasion resistance tests when the amount (molar ratio) was changed are shown in (Table 6) below.

【0087】

[Table 6]

【0088】

SnO for abrasion resistance test₂It improved with the increase in the amount of water, and with the addition of 10% or more, no scratches were made and no change occurred even in 40 sliding tests. Regarding the antibacterial test, if the range was 20% or more, it was +++ as in the case of no addition, and if it was up to 60%, it stopped at ++. If more is added, TiO on the surface of the base material₂The probability of covering the particles increased, the antibacterial property deteriorated, and it became-at 100%. Therefore SnO₂Addition amount of TiO in molar ratio₂If the amount is 10% or more and 60% or less, preferably 10% or more and 20% or less, a multifunctional material having excellent antibacterial properties and abrasion resistance can be provided.

【0089】

Here the wear resistance is SnO₂It is due to the mechanism shown below that it improves as the amount of. That is, SnO₂Is TiO₂Since the vapor pressure is high at a high temperature of 600 ° C or higher, TiO before sintering₂The spacing between the particles 3b is Lo as shown in Fig. 4 (a), but TiO₂The surface of particle 3b with a positive curvature has a high vapor pressure and the surface with a negative curvature, that is, two TiO₂The vapor pressure is low on the surface of the neck where the particles 3b come into contact. As a result, as shown in Fig. 4 (b), the neck part is TiO.₂SnO with higher vapor pressure than₂Enters, condenses as shown in Fig. 4 (c), and is sintered by the vaporization-condensation mechanism. Then, when sintering is performed by the vaporization-condensation mechanism, TiO after sintering is performed.₂Particle spacing L₂Is substantially equal to the interval Lo before sintering, so cracks and the like do not occur. In this way, TiO is placed on the surface of the base material via a binder.₂In the composite member in which the particle layer is retained, it is exposed on the outermost surface and TiO₂SnO in the gaps between particles₂If the particles are filled and fired at 600 ° C or higher, TiO without cracking.₂Since the neck portion between the particles can be bonded, the wear resistance property is improved.

【0090】

(Comparative example 7) SiO on the surface of a 150-square ceramic tile substrate as in Example 6.₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂Sol and SiO₂An aqueous solution in which the sol was mixed and stirred was applied by a spray coating method, and then calcined at 750 ° C. to be cooled and solidified to obtain a multifunctional material. TiO₂Sol concentration is 4 ~ 6wt% and NH₃Adjusted to PH11 with an aqueous solution, the crystallite diameter of the particles is 0.01 μm as in Example 6, but SnO₂The crystallite diameter of the particles was 0.008 μm, which was rather large.

【0091】

The results of antibacterial and abrasion resistance tests performed on the multifunctional material thus produced and compared with Example 6 are shown in (Table 7) below.

【0092】

[Table 7]

【0093】

As a result, 0.008 μm SnO₂The effect of improving the wear resistance of particles is 0.0035 μm SnO.₂Weaker than with particles, TiO₂When the molar ratio to the particles was 60% or more, no scratches were made and no change occurred even in the sliding test 40 times. 0.0035 μm SnO for antibacterial test₂As in the case of using particles, if the range was 20% or more, it was +++ as in the case of no addition, and if it was 60% or less, it stopped at ++. If more is added, TiO on the surface of the base material₂The probability of covering the particles increased, the antibacterial property deteriorated, and it became-at 100%. Therefore 0.01 μm TiO₂0.008 μm SnO when using particles₂It is difficult to add particles to provide a multifunctional material having excellent antibacterial and abrasion resistance. The cause of this is SnO₂The vapor pressure of the particles decreases as the grain diameter increases, and SnO remains without vaporization.₂TiO if the particles are 0.0035 μm₂It was present in the gaps between the particles and could improve the bond strength, whereas at 0.008 μm it was TiO.₂SnO compared to the interparticle gap₂SnO due to the large particles₂Particles do not enter the gap, rather TiO₂This is probably because the probability of coming on the particles is high. From the above, TiO₂SnO to fill the gaps between particles₂The particle size is TiO₂It is preferably less than 4/5 with respect to the particle size.

【0094】

(Reference example 8) SnO on the surface of 150 square ceramic tile base material₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, SnO is applied to the composite member that is fired at 750 ° C and cooled and solidified.₂An aqueous sol solution was applied by a spray coating method and then heat-treated at 110 ° C to obtain a multifunctional material. At this time, TiO₂The same sol aqueous solution as in Example 6 was used, and SnO was used.₂The sol used was 0.0035 μm.

【0095】

The results of antibacterial and abrasion resistance tests on the multifunctional material thus produced are shown in (Table 8) below.

【0096】

[Table 8]

【0097】

SnO for abrasion resistance test₂With the addition of 20% or more of the molar ratio, there was no damage and no change even in the 40-time sliding test. Regarding the antibacterial test, if the range was 20% or more, it was +++ as in the case of no addition, and if it was up to 60%, it stopped at ++. If more is added, TiO on the surface of the base material₂The probability of covering the particles increased, the antibacterial property deteriorated, and it became-at 100%. SnO in this test₂Since the sol is heat-treated at a low temperature of 110 ° C, wear resistance is improved even though sintering by the vaporization-condensation mechanism shown in Example 6 does not occur, which is TiO.₂SnO has a smaller particle size than particles, that is, has a large specific surface area and excellent adsorption power.₂Particles are TiO₂By filling the gaps between the particles, TiO₂It is considered that the bond between the particles was strengthened.

【0098】

(Reference example 9) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, the composite member that was fired at 750 ° C and cooled and solidified was coated with the copper acetate aqueous solution and dried, and then irradiated with light containing ultraviolet rays to reduce copper ions. It was fixed to the photocatalyst layer to obtain a multifunctional material. Here, a mercury lamp was used as the irradiation lamp. Here, the size of the Cu particles fixed to the photocatalyst layer was about 0.004 μm on average.

【0099】

The results of antibacterial and abrasion resistance tests on the multifunctional material thus produced are shown in (Table 9).

【0100】

[Table 9]

【0101】

The abrasion resistance test improved as the amount of Cu increased, and by adding 20% or more of the molar ratio, no scratches were made and no change occurred even in the sliding test 40 times. Regarding the antibacterial property test, if it was in the range of 20% or more, it was +++ as in the case of no addition. In the case of Cu, since it has antibacterial activity by itself, no deterioration of antibacterial activity was observed by adding a large amount. However, probably when the amount of Cu added is small, TiO₂It can be considered that the photocatalytic action of the particle layer is dominant, and when the amount of Cu added is large, the action of Cu is dominant. When the action of Cu alone is expected, Cu gradually elutes when used in a liquid, so it is considered that the life is shorter than that in the case without a photocatalyst. In addition, the larger the amount of Cu added, the higher the cost. Therefore, it seems meaningless to set the amount of Cu too large. SnO by this example₂Not only oxides such as Cu, but also metals such as Cu TiO₂It was confirmed that the particles could fill the gaps in the particle layer.

【0102】

(Reference example 10) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, the copper acetate aqueous solution is applied to the composite member that has been fired at 950 ° C and cooled and solidified, and then the photocatalyst layer is irradiated with light containing ultraviolet rays to reduce copper ions. A multifunctional material was obtained by fixing to. At this time, a BLB lamp was used as the irradiation lamp, and irradiation was performed for several minutes. TiO₂Made a phase transition from anatase to rutile during the heat treatment process. TiO₂The film thickness was adjusted to 0.4 μm during spray coating.

【0103】

The multifunctional material thus produced was subjected to an antibacterial property test and an abrasion resistance test. As for the abrasion resistance test, good results are shown in this temperature range even without addition. Even with the addition of Cu, there was no damage and no change in the sliding test 40 times as in the case of no addition. The antibacterial test is shown in Fig. 5. TiO when no additives are added₂However, it is bad as + because of rutile. The antibacterial property of adding Cu to it increased. And the Cu loading amount is 0.7 μg / cm not only when irradiating with BLB lamp but also when not irradiating.²If the above is achieved, the antibacterial activity becomes ++ and the amount of Cu supported is 1.2 μg / cm.²If the above is achieved, the antibacterial activity becomes +++. From the above, in order to provide a multifunctional material with excellent antibacterial and wear resistance, the Cu loading amount is 0.7 μg / cm.²The above is good, more preferably 1.2 μg / cm²The above is good.

【0104】

By the way, the amount of Cu supported is dramatically improved by adding a drying step after applying the cupric acetate aqueous solution and before irradiating the BLB lamp. The relationship is shown in Fig. 6. It is considered that this is because the metal ion concentration at the time of photoreduction is higher when dried.

【0105】

The Cu carrying amount is maximized when the Cu coating amount is optimized (Fig. 7 is an example of copper acetate with a Cu concentration of 1 wt%). In the case of Fig. 7, the Cu consumption amount is 0.7 μg / cm.²To achieve the above, the Cu coating amount should be 0.2 mg / cm.²More than 2.7mg / cm²Below, Cu consumption is 1.2 μg / cm²To achieve the above, the Cu coating amount should be 0.3 mg / cm.²More than 2.4mg / cm²It can be done as follows.

【0106】

(Reference example 11) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 680 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, the composite member that was fired at 950 ° C and cooled and solidified was coated with the silver nitrate aqueous solution, dried, and then irradiated with light containing ultraviolet rays to reduce silver ions and photocatalyst. It was fixed to a layer to obtain a multifunctional material. At this time, a BLB lamp was used as the irradiation lamp, and irradiation was performed for several minutes. Also TiO₂Made a phase transition from anatase to rutile during the heat treatment process. TiO₂The film thickness was adjusted to 0.4 μm during spray coating.

【0107】

The multifunctional material thus produced was subjected to an antibacterial property test and an abrasion resistance test. As for the abrasion resistance test, good results are shown in this temperature range even without addition. Even with the addition of Ag, there were no scratches or changes in the 40 sliding tests as in the case without the addition.

【0108】

For antibacterial test, TiO when no additive is added₂However, it is bad as + because of rutile. The antibacterial property increased as Ag was added to it. And not only when irradiating with BLB lamp, but also when not irradiating, the amount of Ag supported is 0.05 μg / cm.²If the above is achieved, the antibacterial activity becomes ++ and the amount of Ag carried is 0.1 μg / cm.²If the above is achieved, the antibacterial activity becomes +++. Therefore, in order to provide a multifunctional material with excellent antibacterial and wear resistance, the Ag loading amount is 0.05 μg / cm.²The above is good, more preferably 0.1 μg / cm²The above is good. However, if the amount of Ag carried is large, it will be colored from brown to black, and the appearance will be poor. However, the amount of Ag carried is 1 μg / cm.²If it is below, there is no coloring. From the above, the amount of Ag carried is 0.05 μg / cm.²More than 1 μg / cm²The following is better, more preferably 0.1 μg / cm²More than 1 μg / cm²The following is good.

【0109】

(Reference example 12) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 680 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, the composite member that was fired at 950 ° C and cooled and solidified was coated with the silver nitrate aqueous solution, dried, and then irradiated with light containing ultraviolet rays to reduce silver ions and photocatalyst. It was fixed to a layer to obtain a multifunctional material. At this time, a BLB lamp was used as the irradiation lamp, and irradiation was performed for several minutes. Also TiO₂Made a phase transition from anatase to rutile during the heat treatment process.

【0110】

Regarding the multifunctional material produced in this way, TiO₂Abrasion resistance test, antibacterial property test and stain resistance test were carried out by changing the film thickness of. As for the abrasion resistance test, good results were shown in all the ranges within 2 μm tested this time, and even in the 40 times sliding test, there was no scratch and no change. For the antibacterial test, ++ is obtained when the film thickness is 0.1 μm or more, and +++ is obtained when the film thickness is 0.2 μm or more. Therefore TiO₂The film thickness of is preferably 0.1 μm or more, preferably 0.2 μm or more.

【0111】

(Reference example 13) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, on which zinc chloride aqueous solution or TiO₂The sol aqueous solution was applied by a spray coating method and dried, and then the silver nitrate aqueous solution was applied, and then the silver nitrate solution was fixed to the photocatalyst layer while being irradiated with light containing ultraviolet rays to reduce silver ions. After that, it was calcined at 900 ° C or higher and 1000 ° C or lower and cooled and solidified to obtain a multifunctional material. At this time, a BLB lamp was used as the irradiation lamp, and irradiation was performed for several minutes. Also TiO₂Made a phase transition from anatase to rutile during the heat treatment process. In addition, since the Ag fixed on the surface changed from brownish black to white with the heat treatment, it is considered that it changed to silver oxide during firing. However, the adhesion and fixation of Ag were performed discretely, and the growth of Ag particles before and after firing was hardly observed by observation.

【0112】

The multifunctional material thus produced was subjected to an antibacterial property test and an abrasion resistance test. As for the abrasion resistance test, good results are shown in this temperature range even without addition. Even with the addition of Ag, there were no scratches or changes in the 40 sliding tests as in the case without the addition. For antibacterial test, TiO when no additive is added₂However, it is bad as + because of rutile. The antibacterial property increased as Ag was added to it.

【0113】

(Reference example 14) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, the silver nitrate aqueous solution is applied to the composite member that has been calcined and solidified by firing at 900 ° C or higher and 1000 ° C or lower, and then irradiated with light containing ultraviolet rays to reduce silver ions. While fixing to the photocatalyst layer, 0.1 mol / l KI aqueous solution is further applied to 0.1 cc / cm.²And then irradiated with ultraviolet rays for about 5 seconds to obtain a multifunctional material. At that time, the amount of Ag carried is 2 μg / cm.²And said. 0.1 cc / cm of 0.1 mol / l KI aqueous solution²By applying the above ratio and irradiating with ultraviolet rays for about 5 seconds, the brown-black multifunctional material was decolorized to white, and the appearance was improved.

【0114】

(Reference example 15) On the surface of 150 square ceramic tile base material, SiO₂-Al₂O₃-A binder layer consisting of BaO frit (softening temperature 620 ° C) is formed, and TiO is formed on the binder layer.₂After applying the sol aqueous solution by the spray coating method, the multifunctional material obtained by firing at 820 ° C and cooling and solidifying is arranged at an angle, and while irradiating the multifunctional material with light containing ultraviolet rays, many While circulating the bath water collected in the public bath on the functional material, it was continuously dropped and the change in the bath water was observed. A similar device was dropped onto a substrate without a photocatalytic layer for comparison. Observation after 14 days showed that the bath water dropped on the multifunctional material had a peculiar difference in turbidity as compared with the bath water dropped on the base material without the photocatalyst layer. Although it was not possible, there was a difference in the odor of water. That is, in the bath water dripping on the base material without the photocatalyst layer, a fairly strong odor of water was observed, and slime-like slime and organic precipitate were observed on the base material. None of them was observed in the bath water dripping onto the multifunctional material. From the above simulation experiments, it is considered that this multifunctional material can be used as a paving stone for artificial waterfalls and fountains in water circulation systems in parks, department stores, etc.

【0115】

[Effect of the invention]

As is clear from the above description, according to the present invention, the photocatalyst particles are fixed via a binder layer made of a material having a temperature lower than the softening temperature of the base material, and in particular, the photocatalyst particles constituting the surface layer portion of the photocatalyst layer are Since the photocatalytic particles are not buried in the binder layer, the surface of the photocatalytic particles is substantially exposed to the outside, and the photocatalytic effect can be sufficiently exerted. Further, among the photocatalyst particles, some of the particles constituting the lower layer of the photocatalyst layer are embedded in the binder layer, so that the holding power of the photocatalyst layer is significantly improved and peeling or the like is less likely to occur.

[Simple explanation of drawings]

[Figure 1]

The figure explaining the manufacturing method of the multifunctional material which has a photocatalytic function which concerns on this invention. [Figure 2]

Enlarged view of the main part of Fig. 1 (d) [Fig. 3]

TiO₂Enlarged view between particles [Fig. 4]

(a) ~ (c) are TiO₂Diagram explaining the mechanism of particle sintering [Fig. 5]

Graph showing test results for antibacterial test [Fig. 6]

Graph showing the test result about the amount of Cu supported when the drying process is inserted before the BLB lamp irradiation [Fig. 7]

Graph showing the relationship between the amount of Cu supported and the amount of Cu applied [Explanation of symbols]

1 ... base material, 2 ... binder layer, 3 ... photocatalyst layer, 3a ... photocatalyst particles constituting the lower layer on the binder layer side of the photocatalyst layer, 3b ... with the outside air of the photocatalyst layer Photocatalytic particles that make up the surface layer in contact, 3c ... Particles filled to bond photocatalytic particles to each other.