CN1120819A

CN1120819A - Multi-functional material having photo-catalytic function and production method therefor

Info

Publication number: CN1120819A
Application number: CN94191730A
Authority: CN
Inventors: 渡部俊也; 小岛荣一; 则本圭一郎; 木村太门; 町田光义; 早川信; 北村厚; 千国真; 佐伯义光; 久我辰彦; 中岛靖
Original assignee: Toto Ltd
Current assignee: Toto Ltd
Priority date: 1993-12-10
Filing date: 1994-12-09
Publication date: 1996-04-17
Anticipated expiration: 2014-12-09
Also published as: CN1102445C

Abstract

Multi-functional materials are classified into those which have a photocatalytic layer 2 with a photocatalytic function directly disposed on the surface of a base 1 and those which have a photocatalytic layer 2 with a photocatalytic function disposed on the surface of a base 1 through a binder layer 6 interposed therebetween. Photocatalytic particles of the photocatalytic layer 2 are joined together by a surface energy or solid-state sintering. The photocatalytic layer 2 may have a structure in which fine particles fill interstices defined between photocatalytic particles or a structure in which no fine particles fill interstices defined between photocatalytic particles. A metal such as Ag, Pt, or the like may be fixed or not fixed to surfaces of the photocatalytic particles.

Description

Multifunctional material with photocatalytic function and method for producing same

Technical Field

The present invention relates to a multifunctional material exhibiting a deodorizing function, an antibacterial function, a sterilizing function, an antifouling function, and the like, and a method for producing the same.

Background

TiO is known as a substance that promotes the decomposition (oxidation) of an organic compound such as a malodorous component by the adsorption or desorption of oxygen molecules by ultraviolet irradiation₂、V₂O₅、ZnO、WO₃Etc., especially TiO in the anatase form₂Since particles have a high photocatalytic effect, it has been proposed to form a photocatalytic layer on the surface of wall materials, tiles, glasses (mirrors), circulating filters, sanitary ceramics, and the like.

As a method for forming the above photocatalyst layer, there is known a method of directly forming a layer of TiO on the surface of a base material such as plastic, ceramic or resin by CVD (chemical vapor deposition), sputtering or electron beam evaporation₂A photocatalyst layer composed of particles or the like.

However, when the CVD method, the sputtering method, the electron beam deposition method, or the like is used, the equipment scale is large, the yield is low, and the manufacturing cost is high.

Other known methods for forming a photocatalyst layer include a method in which photocatalyst particles are kneaded into a binder and coated on the surface of a base material by a spray coating method or the like, or a method in which the photocatalyst particles are dip-coated by a dip coating method and then subjected to a heat treatment (Japanese patent application laid-open No. 5-201747).

However, in order to make TiO₂Photocatalyst particles such as particles exert the effect of a photocatalyst, and it is necessary to decompose photocatalyst particles by irradiating the photocatalyst particles with ultraviolet rays and bringing the photocatalyst particles into contact with malodorous gases or the likeHowever, if photocatalyst particles are kneaded into a binder and then coated on a substrate as in Japanese patent application laid-open No. 5-201747, many photocatalyst particles are embedded in the binder layer, and ultraviolet rays do not reach the binder layer, and malodorous gas does not come into contact with the binder layer, and thus the catalyst function cannot be sufficiently exhibited.

Other methods for forming a photocatalyst layer are known as well as the alkoxylate method disclosed in Kaiping 5-7394. The method comprises coating titanium alkoxide on a glass substrate, drying, calcining at several hundred degrees centigrade to form a photocatalyst layer, and irradiating the photocatalyst layer with ultraviolet rays to decompose organic substances in water.

The above alkoxide method is advantageous in that a thin film can be formed at a relatively low temperature, and a base material such as hard glass or quartz glass which is difficult to soften at a temperature as high as 500 ℃ can be effectively used as a base material, but when a base material having a low melting point such as soda-lime glass is used as a base material, for example, the base material starts to soften at a temperature at which the thin film is formed, and the formed photocatalyst thin film is embedded in the base material, so that light cannot reach the photocatalyst layer, and a problem that the photocatalyst function cannot be exhibited occurs.

In addition, in Japanese patent laid-open No. Hei 1-288321, TiO is added₂Spraying the sol on the fibrous ceramic paper, carrying out heat treatment at 400-700 ℃, and then spraying SnO₂The sol is heat-treated at 400-700 ℃ to form a photocatalyst coating film capable of improving the aldehyde oxidative decomposition.

In the method disclosed in Japanese patent laid-open No. 1-288321, TiO is used as a catalyst₂Less active SnO₂Covering the entire surface of the cover film. Moreover, when the film strength is increased, cracks are easily generated. That is, as shown in FIG. 1(a), TiO-containing coating is applied to the surface of the tile 100₂When the sol of the particles 101 is heat-treated (sintered), cracks 102 are generated as shown in fig. 1 (b). This is because, in addition to volume shrinkage (increase in density) due to the transformation to the rutile phase, TiO is present before sintering as shown in FIG. 2(a)₂The spacing between the particles 101 is L₀However, in the rutile type, after sintering, as shown in FIG. 2(b), the volume diffusion to the opposite side shortens the interparticle distance to L₁(L₁＜L₀) Therefore, it is considered that cracks are generated as a result.

On the other hand, Japanese patent application laid-open No. 4-46609 discloses a method for purifying odor in a vehicle interior, which is a method for decomposing or modifying an offensive odor substance contained in the odor of the air in the vehicle interior to purify the odor in the vehicle interior, characterized in that a semiconductor solid photocatalyst in which a metal or a metal oxide is supported on a semiconductor is irradiated with light, and the air in the vehicle interior to be purified is brought into contact with the photocatalyst, thereby decomposing or modifying the offensive odor substance contained in the odor in the air by a photochemical reaction.

However, when a substrate having a photocatalyst coated on the surface thereof is used in environments such as sewage and exterior walls, contaminants are likely to adhere to the substrate due to the presence of polymers, dust, bacteria, and the like in the atmosphere or in water, and the function of the photocatalyst may be deteriorated due to the adhesion of contaminants depending on the type of contaminants.

A prior strategy for dealing with the decrease in photocatalyst function caused by the adhesion of contaminants is disclosed in Japanese examined patent publication No. 6-7905. Japanese examined patent publication No. 6-7905 discloses a deodorizing apparatus using a photocatalyst, which comprises a semiconductor photocatalyst layer, and an ultraviolet lamp, a heating element and a blower provided so as to face the semiconductor photocatalyst layer, wherein the photocatalyst layer or the heating element, or the photocatalyst layer and the heating element are moved so as to heat the entire photocatalyst layer in order, and the photocatalyst layer is heated to a temperature of about 400 ℃ to remove contamination caused by polymers, dust, etc., thereby regenerating the photocatalyst layer.

However, since it is difficult to actually implement the photocatalyst regeneration method for a member used in a device installed indoors, it is desired that after the contamination is attached to the photocatalyst layer, the contamination is not removed, and the contamination is not easily attached, or the problem is solved more fundamentally so that the attachment of the contamination does not lower the function of the photocatalyst.

Furthermore, Japanese examined patent publication No. 6-7906 discloses a method of removing offensive odors in homes and offices by irradiating a photocatalyst with intense ultraviolet light. However, when the photocatalyst is irradiated with strong ultraviolet light, the decomposition rate of the offensive odor varies depending on the structure of the photocatalyst. In the above examples, the base material is porous and sufficient mechanical strength is obtained by impregnation or the like, but sufficient mechanical strength is not obtained when the base material is a non-porous material such as a glazed tile or a dense and fine ceramic.

In addition, in TiO₂Among them, there are different crystal forms such as anatase type, brookite type, and rutile type, and in terms of photoactivity, anatase type is preferable, and photoactivity of other crystal forms is not so good. However, even rutile TiO₂Metals such as Pt and Ag supported on the surface of the substrate also improve the photoactivity (reported in journal of surface 1987, Vol 25), but are insufficient in terms of malodor removal rate, denseness and tackiness. In particular, when Ag and AgO are added, they are not compatible with the tile and the building material because they are black.

In addition, since the titania sol prepared by a hydrothermal method, a sulfuric acid method, or the like is composed of ultrafine particles, it is easily coagulated. When the aggregate is applied to the surface of the substrate, the aggregate causes generation of spots and cracks. Therefore, in order to prevent the coagulation, a method of attaching an organic dispersant such as triethanolamine to the surface of the titanium oxide sol has been conventionally employed.

However, in the case of the method of adhering an organic dispersant such as triethanolamine to the surface of a titanium oxide sol, when a monodispersed titanium oxide sol is applied to a base material having low heat resistance such as a resin base material and the base material is baked and fixed at a temperature of less than 300 ℃, the organic dispersant is firmly fixed at the active sites of the titanium oxide sol and is not sufficiently decomposed by evaporation even in the baking process, and therefore, the member obtained in this way does not have a sufficient photocatalytic effect and is insufficient in odor-proofing property and antibacterial property.

Japanese unexamined patent publication Hei 5-253544 discloses a method in which anatase-type titanium oxide is mixed with a binder, and the mixture is applied to the surface of a substrate and then heat-treated. The method comprises forming an adhesive layer on the surface of a plate-like member constituting the wall surface, floor surface or ceiling surface of a living space, spraying a photocatalyst fine powder mainly composed of anatase-type titanium oxide on the surface of the adhesive layer to expose a part of the photocatalyst fine powder from the adhesive layer, adhering the photocatalyst fine powder to the surface of the adhesive layer, heating the adhesive layer at a temperature of 300 ℃ to 900 ℃ inclusive to melt the adhesive layer, and cooling the adhesive layer to solidify the adhesive.

In this method, the deodorizing property is good when the heat treatment is performed at 300 ℃ to 900 ℃ inclusive, but good deodorizing property is not obtained at a low temperature of 200 ℃ or lower. Therefore, it is difficult to add a photocatalyst having excellent deodorizing property to a base material such as a heat-labile plastic. The reason is considered to be that in order to uniformly coat the photocatalyst particles on the substrate, it is necessary to first monodisperse the photocatalyst fine particles in a suspension, and for this purpose, an organic dispersant is added, which does not sufficiently decompose, gasify, and remain to cover the active sites on the photocatalyst particles at 300 ℃.

Accordingly, an object of the present invention is to provide a photocatalyst-layer-supporting material which can sufficiently exhibit a photocatalytic effect so that a photocatalyst layer is exposed from a base material and which can particularly well hold the photocatalyst layer by the base material.

It is another object of the present invention to form a photocatalyst layer which is not easily peeled off on a relatively dense substrate such as glass, tile, metal, or plastic.

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

Further, an object of the present invention is to provide a multifunctional material which is less likely to adhere to contaminants, can prevent a decrease in function due to contaminants, has antibacterial properties and deodorant properties, and has excellent mechanical strength.

Further, the present invention has an object to provide TiO in anatase form₂The photocatalyst layer as a main body is a multifunctional material having excellent peel strength.

Furthermore, it is an object of the present invention to improve the performance of the rutile form of TiO₂Photocatalytic activity of the photocatalyst layer as a main body.

Furthermore, the present invention is directed to a rutile type TiO compound₂Ag is supported on the photocatalyst layer as the main body, so that the photocatalytic activity is improved, and the photocatalyst layer is decolorized, so that the appearance is better.

Further, the present invention aims to provide a multifunctional material having a good photocatalytic function even when heat treatment is performed at a low temperature of 300 ℃.

Disclosure of the invention

The multifunctional material of the present invention is a material in which a photocatalyst layer is formed directly or via a binder layer on the surface of a base material such as ceramics including tiles, sanitary ceramics, glass, etc., resins, metals, wood, etc., and particularly, there is no particular requirement for the kind and particle size of photocatalyst particles constituting the photocatalyst layer, the gap formed between the photocatalyst particles, the porosity, the relationship between the binder layer and the photocatalyst layer, particles filling the gap between the photocatalyst particles, particularly metal particles fixed on the surface of the photocatalyst particles, etc., and a multifunctional material having excellent photocatalytic effect as a photocatalyst layer for deodorization, etc., and also excellent antibacterial properties and abrasion resistance is produced by using these materials.

Brief description of the drawings

FIG. 1(a) shows a conventional TiO compound₂The state before sintering of the sol, and (b) the state after sintering of rutile type.

FIG. 2(a) shows a conventional TiO compound₂The state before sintering of the particles, and (b) is a state after sintering.

FIG. 3 is a view showing a state in which photocatalyst particles constituting a photocatalyst layer are bonded to each other by potential energy in the multifunctional material having a photocatalytic function of the present invention.

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

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

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

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

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

Fig. 9 is a view schematically showing a state in which photocatalyst particles constituting a photocatalyst layer are bonded to each other with potential energy in the same multifunctional material by bonding the photocatalyst layer to a base material via an adhesive layer.

FIG. 10 is a view schematically showing a state in which photocatalyst particles constituting a photocatalyst layer are bonded to each other by solid-phase sintering in the same multifunctional material, the photocatalyst layer being bonded to a base material via an adhesive layer.

Fig. 11 is a view schematically showing a state in which the photocatalyst layers are bonded to each other by the adhesive layer and the gaps formed between the photocatalyst particles are filled with small particles in the same multifunctional material.

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

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

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

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

FIGS. 16(a) and (b) are TiO₂Enlargement of the interparticle.

FIGS. 17(a) - (c) are diagrams illustrating TiO₂Sintering mechanism diagram of the particles.

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

Fig. 19 is a graph showing a comparison of test results of Cu loading between the drying process before irradiation of the BLB lamp and the drying process without irradiation of the BLB lamp.

Fig. 20 shows a relationship curve between the amount of Cu supported and the amount of Cu applied.

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

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

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

Fig. 24 shows a relationship curve between the amount of Cu supported and the amount of Cu applied.

FIG. 25 is a graph showing the relationship between Ag loading and bacterial survival rate.

FIG. 26 is a conceptual diagram of the basic distribution of a multifunctional material observed in the cross-sectional direction by an EPMA (Electron Beam micro analyzer).

FIG. 27 is a conceptual diagram of the basic distribution of a multifunctional material observed in the cross-sectional direction by an EPMA (Electron Beam micro analyzer)

FIG. 28 shows TiO₂And SnO₂The fit of (a) is a curve relating film strength and smoothness.

FIG. 29 shows the heat treatment temperature versus finish.

FIG. 30 is a view for explaining a method of measuring the activity of a photocatalyst thin film.

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

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

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

FIG. 34 shows R₃₀Change in pH.

FIG. 35 shows porosity and odor resistance (R)₃₀) And wear resistance.

FIG. 36 shows the film thickness and odor resistance (R)₃₀) The relationship of (1).

FIG. 37 shows the film thickness and odor resistance (R)₃₀) And a relationship curve of peeling resistance.

FIG. 38 shows SnO₂Addition amount and odor resistance (R)₃₀) And wear resistance.

FIG. 39 shows SnO₂The relationship curve of the addition amount and the pollution attachment difficulty.

FIG. 40 shows SnO₂In addition to TiO₂Open porosity of the surface of the layer.

FIG. 41 shows SnO₂In addition to TiO₂The open pore width of the layer surface.

FIG. 42 shows SnO₂Addition amount and odor resistance R₃₀(L) and peel resistance.

FIG. 43 shows porosity and odor resistance R₃₀(L) and abrasion resistance.

Fig. 44 shows a graph of the relationship between the number of coating times and the degree of adhesion of contaminants.

Fig. 45 shows a graph of the number of coating times versus the abrasion resistance.

FIG. 46 shows the number of coating times and TiO₂Open porosity of the surface of the layer.

Fig. 47 is a view showing a state where the thermosetting resin on the photocatalyst particles is preferentially decomposed and gasified by irradiation with ultraviolet rays, and the photocatalyst particles are exposed to the air.

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

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

Fig. 50 is a view showing a state where the photocatalyst particles are filled with small particles in the gaps.

FIG. 51 shows the use of rutile type TiO₂A block diagram of a manufacturing process of the multifunctional material of (1).

Fig. 52 shows a graph of the relationship between the concentration of the Cu solution and the photoactivity when the Cu solution was dried and subjected to the photoreduction.

Fig. 53 shows a graph of the relationship between the concentration of the Cu solution and the photoactivity when the Cu solution was subjected to the photoreduction without drying.

FIG. 54 shows a rutile type TiO₂Concentration of Cu solution and odor removal rate R when Cu is used as a supporting metal on a thin film₃₀The relationship (reduction of metal ions is carried out after drying the aqueous metal salt solution).

FIG. 55 shows a rutile type TiO based tile₂Concentration of Cu solution and odor removal rate R when Cu is used as a supporting metal on a thin film₃₀In the case of reducing metal ions in an aqueous solution of a metal saltAfter drying).

FIG. 56 shows the formation of rutile TiO₂Roasting temperature of film and odor removal rate R after Cu immobilization₃₀The relationship of (1).

FIG. 57 is a graph showing the relationship between the concentration of Ag and Cu in a solution and the color difference.

FIG. 58 shows porosity and R₃₀And wear resistance.

FIG. 59 is a graph showing the relationship between the copper loading and the bacterial survival rate.

Fig. 60 shows a relationship curve between the amount of copper applied and the amount of copper supported.

FIG. 61 shows a graph of the relationship between the amount of silver loaded and the survival rate of bacteria.

Fig. 62 shows a relationship between the amount of silver supported and the color difference.

FIG. 63 is a graph showing the effect of decoloring with an aqueous KI solution.

FIG. 64 shows the change in pH and the odor removal rate R of an aqueous KI solution before and after a decoloring treatment with an aqueous KI solution₃₀A relationship curve of change.

Fig. 65 is a graph comparing antibacterial effects.

Fig. 66 shows a graph of wear resistance against the weight ratio of tin oxide in the thin film.

FIG. 67 shows the graph of photoactivity versus weight ratio of tin oxide in the film.

Fig. 68 shows a graph of wear resistance with respect to the weight ratio of tin oxide in the film as a comparative example.

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

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

Best Mode for Carrying Out The Invention

To describe the present invention in more detail, the present invention is illustrated in accordance with the accompanying drawings.

Fig. 3 to 14 are views for dividing the structure of the multifunctional material having a photocatalytic function according to the present invention into various types, and the multifunctional material having a photocatalytic function according to the present invention belongs to one of the structures.

In the multifunctional material shown in fig. 3, a photocatalyst layer 2 having a photocatalytic function is directly provided on the surface of a base material 1, and the photocatalyst layer 2 is formed by mutually combining fine photocatalyst particles 3 with surface energy, curved surface energy, and the like.

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

In the multifunctional material shown in fig. 5, a photocatalyst layer 2 having a photocatalytic function is directly provided on the surface of a base material 1, and the photocatalyst particles 3 constituting the photocatalyst layer 2 are bonded to each other by the small particles 4 filled in the gaps formed between the photocatalyst particles 3 and smaller than the gaps.

In the figure, the particles 4 are shown as being filled in the inner gaps, but the particles 4 may be filled at least in the gaps of the surface layer photocatalyst particles 3. That is, since the mechanical strength of the photocatalyst layer is considered to be important for attenuating the transmission of external force inside, it is possible to fill only the gaps between the photocatalyst particles in the surface layer with fine particles. However, in this case, the photocatalyst particles inside are bonded by potential energy, and the average particle diameter of the photocatalyst particles is preferably 0.04 μm in order to obtain sufficient strength of the photocatalyst layer.

In the multifunctional material shown in FIG. 6, the photocatalyst particles 3 having the photocatalyst layer 2 formed directly on the surface constituting the base material 1 are bonded to each other with potential energy, and Ag, Cu and Cu are further fixed to the surfaces of the photocatalyst particles 3₂And electron-collecting particles 5 such as O.

In the multifunctional material shown in fig. 7, the photocatalyst particles 3 constituting the photocatalyst layer 2 directly formed on the surface of the substrate 1 are bonded to each other by solid-phase sintering, and metal particles 5 such as Ag and Pt are fixed to the surfaces of the photocatalyst particles 3.

In the multifunctional material shown in fig. 8, a photocatalyst layer 2 having a photocatalytic function is directly provided on the surface of a base material 1, and particles 4 smaller than the gaps are filled in the gaps formed between photocatalyst particles 3 constituting the photocatalyst layer 2, and the photocatalyst particles 3 are bonded to each other by the small particles 4, and metal particles 5 such as Ag and Pt are fixed to the surfaces of the photocatalyst particles 3.

In the multifunctional material shown in fig. 9, a photocatalyst layer 2 having a photocatalytic function is provided on the surface of a base material 1 via an adhesive layer 6, the photocatalyst layer 2 is configured such that the surface layer is exposed to the outside, the lower layer is embedded in the adhesive layer 6, and the fine photocatalyst particles 3 of the surface layer are bonded to each other with potential energy.

In the multifunctional material shown in fig. 10, the photocatalyst layer 2 is similarly provided with the binder layer 6, and the photocatalyst particles 3 are bonded to each other in the surface layer of the photocatalyst layer 2 by solid-phase sintering.

In the multifunctional material shown in fig. 11, the photocatalyst layer 2 is provided on the substrate 1 via the binder layer 6, and the photocatalyst particles 3 are bonded to each other via the small particles 4 by filling the gaps formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 with the particles 4 smaller than the gaps.

In the multifunctional material shown in FIG. 12, a photocatalyst layer 2 is formed on the surface of a base material 1 via a binder layer 6, photocatalyst particles 3 constituting the photocatalyst layer 2 are bonded to each other with potential energy, and Ag, Cu and Cu are further fixed to the surface of the photocatalyst particles 3₂And electron-collecting particles 5 such as O.

In the multifunctional material shown in FIG. 13, a photocatalyst layer 2 is formed on the surface of a substrate 1 via a binder layer 6, photocatalyst particles 3 constituting the photocatalyst layer 2 are bonded to each other by solid-phase sintering, and Ag, Cu and Cu are further fixed to the surface of the photocatalyst particles 3₂And electron-collecting particles 5 such as O.

In the multifunctional material shown in fig. 14, the photocatalyst layer 2 is provided on the substrate 1 via the binder layer 6, the gaps formed between the photocatalyst particles 3 constituting the photocatalyst layer 2 are filled with particles 4 smaller than the gaps, and the photocatalyst particles 3 are bonded to each other via the small particles 4, whereby metal particles 5 such as Ag and Pt are fixed to the surfaces of the photocatalyst particles 3.

In the above multifunctional material, the substrate 1 may be any of ceramics such as ceramic tiles, sanitary ceramics, and glass, resins, metals, wood, or composites thereof.

The photocatalyst particles 3 are semiconductor particles having a large forbidden band width in order to exhibit photocatalytic functions such as an antibacterial function and a deodorizing function. The reason why the photocatalyst particles have antibacterial properties is that they are electrocuted by applying a voltage of a predetermined level or more, but it is considered that they are a cause of generation of active oxygen upon light irradiation, in general, like the deodorizing function. In order to generate active oxygen, one of the conduction bands of the semiconductor is required, and when expressed by a band model, it must be located above the hydrogen generation potential and the upper end of the valence band must be located below the oxygen generation potential. Among the semiconductors satisfying this condition are TiO₂、SrTiO₃ZnO, SiC, potassium phosphide, CdS, CdSe, MoS₃And the like. Further, since the position of the conduction band moves upward when the particle is made fine, SnO is formed as fine particles of about 1 to 10nm₂、WO₃、FeO₃、Bi₂O₃Etc. are likely to generate active oxygen. Wherein the anatase form of TiO₂It is particularly preferable because fine particles having high activity can be obtained at low cost due to chemical stability.

The electron-trapping particles are particles which trap electrons and prevent the recombination of electrons and holes when the photocatalyst is irradiated with light to generate electrons and holes, and specifically include Ag, Cu, Pt, Pd, Ni, Co, Fe, and Cu₂O, and the like.

The adhesive layer 6 is made of a thermoplastic material such as glaze, inorganic glass, thermoplastic resin, and solder. In this way, the adhesive layer is made of a thermoplastic material, and the photocatalyst can be applied to the adhesive layer at room temperature by a simple and inexpensive method such as spray coating, and the substrate 1, the adhesive layer 6, and the photocatalyst layer 2 can be firmly bonded by only heat treatment, which is advantageous in terms of production cost.

The multifunctional material having a photocatalytic function according to the present invention is formed by laminating a photocatalyst layer composed of photocatalyst particles on a sheet-like adhesive layer composed of a thermoplastic material or by embedding a part of the photocatalyst layer in the adhesive layer. When such a sheet-like multifunctional material is applied to an existing tile, sanitary ceramic, building material, or the like, and then heated, functions such as deodorizing properties, antifouling properties, antibacterial properties, and mold resistance can be added to the existing tile or the like.

The photocatalyst particles 3 constituting the photocatalyst layer 2 preferably have an average particle diameter of 0.3 μm or less because the specific surface area is increased to improve the photocatalytic activity.

The thickness of the photocatalyst layer 2 is preferably 0.1 μm to 0.9. mu.m. At a particle size of 0.1 μm or less, the photocatalyst particles are locally embedded in the binder layer 6, and a portion incapable of exerting catalytic activity is generated on the surface of the multifunctional material, and bacteria are retained in this portion, so that the antibacterial property is particularly deteriorated. If the thickness exceeds 0.9. mu.m, the variation in thickness becomes large, and the stain is less likely to fall off when the stain is attached to the sample. The thickness of the photocatalyst layer includes a portion extending from the outermost surface of the photocatalyst thin film to the portion embedded in the under-glaze layer, and specifically, the thickness is measured by performing elemental analysis such as EPMA (electron beam microanalyzer) to increase the value of the main component element constituting the glaze layer and obtaining the distance from the uppermost portion to the outermost surface of the portion where the value is substantially constant.

In addition, a particular effect can be obtained by a method of changing the thickness of the photocatalyst layer 2. That is, when the thickness is 0.2 μm or more and 0.4 μm or less, an iridescent pattern can be added by the action of light interference in the film thickness direction of the photocatalyst layer, and when it is desired to form only the ground color, pattern or combination thereof of the base material in appearance, the film thickness of the photocatalyst layer may be 0.1 μm or more, 0.2 μm or less, or 0.4 μm or more and 1 μm or less, in addition to the portion where the above-mentioned action of light interference occurs. The method can be used in a wide range of ceramic tiles, wash tables, bathtubs, urinals and urinals, washing tables, kitchen tables and the like.

In the case where only the photocatalyst particles 3 are bonded to each other, only the potential energy (adsorption) or sintering between the photocatalyst particles is utilized. However, when the mutual sintering of the photocatalyst particles is used, sintering must be performed at a relatively high temperature, and when adsorption is used, if the specific surface area of the photocatalyst particles is not made relatively large and the filling property is not made good, the binding property is insufficient, and only the active site adsorption part of the photocatalyst particles is consumed, and the like, and there is a limitation in the method for producing a multifunctional material having sufficient catalytic activity and abrasion resistance.

In addition, if particles larger than the gaps between the photocatalyst particles 3 are used in order to strengthen the bonding of the photocatalyst particles 3, 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, and a portion incapable of exerting catalytic activity is generated on the surface of the multifunctional material, and bacteria are retained in this portion, so the antibacterial property is remarkably deteriorated.

The gaps between the photocatalyst particles referred to herein are the constricted portions between the

photocatalyst particles

3, 3 as shown in fig. 16(a), and the pores between the

photocatalyst particles

3, 3 as shown in fig. 16 (b). Therefore, the small particles 4 having a particle diameter smaller than the gaps between the photocatalyst particles as used herein mean particles having a particle diameter smaller than any of the constricted portions between the photocatalyst particles and the larger gaps between the photocatalyst particles. The method of bonding photocatalyst particles to each other is a particularly effective method as shown in fig. 16 (b).

The small particles 4 filled in the gaps of the photocatalyst particles 3 are not limited to a material, but may be a material having a good adsorbability. The purpose of bonding photocatalyst particles to each other cannot be achieved by using a material having an extremely weak adsorption ability. In addition, when a material having a very strong adsorption ability is used, the probability of covering active sites on the surface of the photocatalyst particles rather than inserting them into the gaps increases. From this point of view, as a material of the particles to be filled in the gaps of the photocatalyst particles, metals or oxides such as Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni and the like are preferable, and zeolite, activated carbon, clay and the like which have been conventionally used as a carrier are not preferable. Among the above metals or oxides, tin oxide is preferable in that it has an appropriate adsorption capacity, and metals or oxides such as Ag and Cu alone have antibacterial and deodorant properties in addition to binding photocatalyst particles to each other, and therefore, in applications utilizing this function, a function of assisting a photocatalytic action particularly in the absence of light irradiation is preferable. That is, the metal particles 5 can be used as the small particles 4 filled in the gaps of the photocatalyst particles 3.

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.

The particles 4 filling the gaps of the photocatalyst particles 3 are attached to some extent not only to the gaps between the photocatalyst particles but also to the photocatalyst particles by the conventional production method. Further, if the particle diameter of the photocatalyst particles filling the gaps exceeds 4/5, the probability of adhesion to the surface of the photocatalyst particles is higher than the probability of filling the gaps between the photocatalyst particles, and the bonding strength between the photocatalyst particles 3 is lowered. If the particles filling the gaps are larger than the photocatalyst particles, the photocatalyst particles are covered in part, and a portion incapable of exerting catalytic activity is generated on the surface of the multifunctional material, and bacteria are retained in this portion, so that the antibacterial property may be significantly deteriorated in particular.

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

Further, the amount of the particles 4 filled in the gaps between the photocatalyst particles 3 is preferably 10% to 60% by mole of the total amount of the photocatalyst particles 3 and the filler particles 4. When the photocatalyst layer is fixed to the substrate by the binder layer through heat treatment in a temperature range in which sintering of the photocatalyst particles does not occur, if the amount of particles filling the gaps is too small, the photocatalyst particles cannot be firmly bonded to each other, while if the amount of particles filling the gaps is too large, the amount of particles covering the photocatalyst particles increases, and a portion incapable of exerting catalytic activity is generated on the surface of the multifunctional material.

Further, as the substance constituting the particles 4 filled in the gaps between the photocatalyst particles 3, a substance having a vapor pressure higher than that of the substance constituting the photocatalyst particles is selected, and it is preferable that the particles filled in the gaps between the photocatalyst particles are aggregated in the constricted parts between the photocatalyst particles. This can achieve stronger bonding between the photocatalyst particles, and not only the filling method but also the sintering method may be used to increase the peel strength of the photocatalyst layer. When such particles 4 having a high vapor pressure are selected as the particles 4 filling the gaps, the sintering temperature can be lowered even when they are used as a sintering aid.

Examples of such a substance having a high vapor pressure include tin oxide, bismuth oxide, and zinc oxide, but tin oxide is preferable from the viewpoint of safety.

The layer thickness of the particles 4 contained in the gaps between the photocatalyst particles 3 is preferably 0.1 μm or more. The thickness of the layer is less than 0.1 μm, and the photocatalyst particles (and particles whose gaps are filled by the production method) are partially embedded in the adhesive layer 6, and a portion which cannot exert catalytic activity is formed on the surface of the multifunctional material, and bacteria can be retained in this portion, so that the antibacterial property is remarkably deteriorated in particular. Here, the layer thickness including the particles 4 filled in the gaps between the photocatalyst particles is a thickness including the average of the respective projections and depressions from the outermost surface to the lower layer portion embedded in the binder layer.

Fig. 15 illustrates an example of the method for producing a multifunctional material having a photocatalytic function according to the present invention, in which first, as shown in fig. 15(a), a substrate 1 is prepared, and as shown in fig. 15 (b), an adhesive layer 6 is formed on the surface of the substrate 1. The adhesive layer 6 is made of a material having a softening temperature lower than that of the base material 1. For example, when the substrate 1 is a tile, a hollow frit, or a ceramic ware, the glaze layer or the print layer may be used as it is as the adhesive layer 6.

Next, as shown in FIG. C, TiO is formed on the adhesive layer 6₂A photocatalyst layer 2 composed of photocatalyst particles such as particles. At this time, the photocatalyst layer 2 may be held by a bonding force not to be detached from the binder layer 6 during the subsequent baking, or may be carried on the binder layer 6.

Alternatively, before the adhesive layer 6 is formed on the surface of the substrate 1, as shown in fig. (b'), the photocatalyst layer 2 may be formed in advance on the adhesive layer 6, and the adhesive layer 6 may be placed on the base 1.

Thereafter, in the range of more than 20 ℃ and 320 ℃ or less, the photocatalyst layer 2 is heat-treated at an atmospheric temperature higher than the softening temperature of the binder layer 6 and lower than the softening temperature of the substrate 1, and as shown in this figure (d) or fig. 9 to 14, a part of the lower layer on the binder layer side is deposited on the melted binder layer, and the binder layer is solidified, so that the part is buried in the binder layer and firmly held. In the photocatalyst layer 2, the photocatalyst particles 3 constituting the surface layer in contact with the external atmosphere are partially bonded as shown in fig. 16(a) by utilizing mutual potential energy, intermolecular force, and sintering by firing, and the other portions are separated as shown in fig. 16 (b). That is, the surface of the photocatalyst particles in the surface layer is substantially exposed to the outside.

Here, it is preferable that the heat treatment temperature is increased to a temperature higher than the softening temperature of the binder layer 6 by more than 20 ℃ and 320 ℃ or less, and if the temperature is lower than 20 ℃, it takes time for the binder to soften, and the photocatalyst particles 3a are not sufficiently held, while if the temperature is higher than 320 ℃, the binder layer is rapidly melted, and the photocatalyst particles are embedded in the binder layer, and uneven surfaces are generated, and chipping and pores are generated, and therefore, 40 ℃ or higher and 300 ℃ or lower are preferable.

Further, assuming that the specific gravity of the photocatalyst particles 3 is δ t and the specific gravity of the binder layer 6 is δ b, the relationship of 0. ltoreq. δ t- δ b. ltoreq.3.0, preferably 0.5. ltoreq. δ t- δ b. ltoreq.2.0 is established. If the difference in specific gravity between the photocatalyst particles and the binder layer is too small, the photocatalyst particles tend to move at a low speed in the vertical direction in the binder layer when the binder layer is melted, and the photocatalyst particles are liable to be peeled off after baking.

Further, as an application of this method, even when δ t- δ b > 3.0 is required, the 2 nd binder layer of 0. ltoreq. δ t- δ b. ltoreq.3.0 may be interposed between the binder layer and the photocatalyst particles.

In addition, when δ t- δ b < 0, the same effect as increasing the specific gravity difference δ t- δ b is obtained when pressure is applied during the heat treatment. Therefore, by the HIP treatment, the hot press treatment can obtain the same effect as that when 0. ltoreq. δ t- δ b. ltoreq.3.0.

Specifically, as shown in fig. 16(a), the constricted portions of the photocatalyst particles 3b or the photocatalyst particles 3 in the space between them constituting the exposed portion of the binder layer 6 may be filled with particles 4 (metal or oxide such as Sn, Ti, Ag, Cu, Zn, Fe, Pt, Co, Pd, Ni, etc.) having a smaller particle diameter than the space in order to bond the photocatalyst particles to each other, as shown in fig. 16 (b).

In addition, as another method for producing the multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material may be formed on a substrate 1 made of a ceramic, a resin, a metal, or the like, and then a mixture in which photocatalyst particles 3 and particles 4 having a small particle diameter are mixed in a sol or a precursor state may be applied on the binder layer 6 to form a photocatalyst layer 2, and thereafter the binder layer 6 is softened to embed a part of the lower layer of the photocatalyst layer 2 in the binder layer 6 and then cured.

According to this method, not only is it easy, but also since the photocatalyst layer is formed by applying a mixture of the particles 4 and the photocatalyst particles 3 which are previously embedded in the gaps in the form of a sol or a precursor, it is convenient to control the mixing ratio of the photocatalyst particles 3 and the particles 4 embedded in the gaps.

In another method for producing the multifunctional material having a photocatalytic function according to the present invention, a mixture of photocatalyst particles 3 and particles 4 having a small particle diameter, which are mixed in a sol or precursor state, is applied to a sheet-shaped adhesive layer 6 made of a thermoplastic material to form a photocatalyst layer 2, the sheet-shaped adhesive layer 6 forming the photocatalyst layer 2 is placed on or bonded to a substrate such as ceramic, resin, or metal, and then the adhesive layer is softened to embed a part of the lower layer of the photocatalyst layer in the adhesive, followed by curing.

Further, as another method for producing the multifunctional material having a catalytic function of the present invention, a binder layer 6 made of a thermoplastic material may be formed on a substrate 1 made of ceramic, resin, metal or the like, then a photocatalyst layer 2 made of photocatalyst particles 3 may be formed on the binder layer 6, then the binder layer 6 may be softened to embed a part of the lower layer of the photocatalyst layer 2 in the binder layer, then the binder layer may be cured, and then a solution containing the small-particle-diameter particles may be applied on the photocatalyst layer, followed by heat treatment to fix the small-particle-diameter particles 4 to the photocatalyst particles.

This method is simple to carry out when the particles filling the gaps are oxides, and can attach a large number of particles filling the gaps when producing a porous photocatalyst layer.

In another method for producing the multifunctional material having a photocatalytic function according to the present invention, the photocatalyst layer 2 comprising the photocatalyst particles 3 may be formed on the sheet-like binder layer 6 comprising the thermoplastic material, the sheet-like binder layer forming the photocatalyst layer may be placed on or bonded to the substrate 1 made of ceramic, resin, metal or the like, the binder layer 6 may be softened to embed a part of the lower layer of the photocatalyst layer 2 in the binder layer 6, the binder layer may be cured, the solution containing the metal particles 4 may be applied to the photocatalyst layer, and the particles having a small particle diameter may be fixed to the photocatalyst particles 3 by heat treatment.

In another method for producing the multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material may be formed on a substrate 1 made of a ceramic, a resin, a metal, or the like, a photocatalyst layer 2 made of photocatalyst particles 3 may be formed on the binder layer 6, the binder layer may be softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, the binder layer may be cured, a solution containing ions of small metal particles 4 may be applied on the photocatalyst layer, and then, a light containing ultraviolet rays may be irradiated to reduce the metal ions and fix the metal ions to the photocatalyst particles.

This method is simple and convenient to carry out when the particles filling the gaps are metal, and can fix the metal in a very short time (several minutes). The lamp used for ultraviolet irradiation may be any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, and a fluorescent lamp.

Further, as another method for producing the multifunctional material having a photocatalytic function of the present invention, a photocatalyst layer comprising photocatalyst particles may be formed on a sheet-like binder layer comprising a thermoplastic material, the sheet-like binder layer 6 forming the photocatalyst layer may be placed on or bonded to a substrate 1 made of ceramic, resin, metal or the like, the binder layer 6 may be softened to embed a part of the lower layer of the photocatalyst layer in the binder layer 6, the binder layer 6 may be cured, a solution containing ions of the small-particle-diameter metal particles 4 may be applied to the photocatalyst layer 2, and then light including ultraviolet rays may be irradiated to reduce the metal ions and fix the metal ions to the photocatalyst particles.

In another method for producing the multifunctional material having a photocatalytic function according to the present invention, a binder layer 6 made of a thermoplastic material may be formed on a substrate 1 made of a ceramic, a resin, a metal or the like, a photocatalyst layer 2 made of photocatalyst particles 3 may be formed on the binder layer 6, a solution containing ions of the small-diameter metal particles 4 may be applied on the photocatalyst layer 2, and then light including ultraviolet rays may be irradiated to reduce the metal ions and fix them on the photocatalyst particles 3, and the binder layer 6 may be softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, and then the binder layer may be cured.

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

Further, as another method for producing the multifunctional material having a photocatalytic function of the present invention, it is also possible to form the photocatalyst layer 2 composed of the photocatalyst particles 3 on the sheet-like binder layer 6 composed of a thermoplastic material, coat a solution containing ions of the metal particles 4 having a small particle size on the photocatalyst layer 2, irradiate light containing ultraviolet rays to reduce the metal ions and fix them on the photocatalyst particles 3, place or attach the sheet-like binder layer on the substrate 1 made of ceramic, resin, metal or the like, and thereafter, soften the binder layer 6 to embed a part of the lower layer of the photocatalyst layer 2 in the binder layer and then cure the binder layer.

Here, ZnO may be used as the photocatalyst particles, and Ag or Ag may be used₂O is used as the metal particles 4 filled in the gaps of the photocatalyst particles. Ag or Ag₂The O particles not only strengthen the combination of photocatalyst ZnO particles, but also strengthen the photocatalytic effect of ZnO, and the O particles also have the antibacterial and deodorant effects. Further, by selecting ZnO as the photocatalyst, coloring due to Ag ions can be eliminated, and unexpected effects can be obtained by the base color, pattern, or combination thereof of the base material.

Further, a solution containing a salt forming an insoluble colorless or white salt may be brought into contact with the photocatalyst layer between the metal ions filled in the gaps of the photocatalyst particles, and then irradiated with light including ultraviolet rays.

Thus, even if ZnO and Ag or Ag are not combined₂O can also eliminate coloring caused by particles filling gaps, and can improve unexpected effects by base colors, patterns, or combinations thereof.

In addition, with TiO₂The photocatalyst particles may be 800 ℃ or higher and 1000 ℃ or lower as the heat treatment temperature for softening the adhesive layer 6. At a temperature above 800 ℃ in TiO₂The particles are generated by sintering at the early stage of formationDespite TiO, so₂The bonding strength between the particles is improved, but if it exceeds 1000 c, the sintering process moves to the middle stage,associated with TiO₂The volume of the photocatalyst layer is significantly shrunk by the solid-phase sintering of (2), and thus cracks are easily generated.

In addition, with TiO₂The photocatalyst particles may be Ag particles 4 filled in the gaps of the photocatalyst particles, and KI, KCl, FCl₃The halide aqueous solution is a solution containing salts which form insoluble colorless or white salts with the Ag ions. Ag forms an insoluble colorless or white salt such as AgI or AgCl with a halogenated base, and therefore, the effect of utilizing the base color, pattern or combination thereof is expected to be improved.

In the case where the dispersion process is provided as a process preceding the process of coating the photocatalyst particles on the binder layer, it is preferable to use only a component that vaporizes at a temperature lower than the heat treatment temperature for softening the binder layer in the dispersant used in the dispersion process for dispersing the sol or precursor to be the photocatalyst particles in the solution.

In the prior art, there is no odor control at temperatures below 320 ℃ because of the adhesion to TiO during dispersion₂The dispersing agent on the surface of the particles is not sufficiently gasified and is evaporated and remained, so that TiO₂The particle surface is not sufficiently exposed to the outermost surface of the substrate, and the photocatalytic function cannot be sufficiently achieved. Further, as the dispersant which vaporizes at low temperature, an organic dispersant having a molecular weight of 1 ten thousand or less and a phosphoric acid-series dispersant are preferable.

Specific examples are listed below.

Example 1

SiO is formed on the surface of a 150-square ceramic tile substrate by a spraying method₂-Al₂O₃-N_a/K₂An adhesive layer of O frit, dried and coated with 15% TiO by spray coating₂Sol aqueous solution to form TiO with a film thickness of 0.8 μm₂Layer, followed by heat-baking in a roller hearth furnace to laminate the binder layer and TiO₂Base material of the layer (atmosphere temperature varies with time)Example by example) and then cooled to solidify, resulting in a multifunctional material.

Here, the term "TiO"₂The sol aqueous solution is prepared by hydrolyzing TiCl in an autoclave under hydrothermal conditions in the range of 100-200 deg.C to obtain a sol having a grain size of about 0.007-0.2 μmAnatase type TiO₂The TiO is added₂In order to improve the dispersibility, an organic base such as triethanolamine or trimethylolamine, or a surface treatment agent such as pentaerythritol or trimethylolpropane may be added in a range of 0.5% or less. In addition, TiO₂The particle size of the sol was processed by image observation using SEM (scanning electron microscope), and the crystal particle size was calculated from the integral width of powder X-ray diffraction.

Although the coating method was performed by a spray coating method, it is expected that similar results will be obtained by a dip coating method and a spin coating method.

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

As for the antibacterial activity, the bactericidal effect against Escherichia coli (Escherichia coli W3110 strain) was tested. 0.15ml (1-5X 10) of bacterial liquid is dropped on the surface of the multifunctional material sterilized by 70% ethanol in advance⁴CFU) placed on a glass plate (10X 10cm) and attached to the surface of the substrate to prepare a sample. After 30 minutes of irradiation with a white lamp (3500 lux), the irradiated sample and the bacterial solution of the sample held under a light-shielding condition were wiped with sterilized gauze and collected in 10ml of physiological saline, and the survival rate of bacteria was determined as an evaluation index.

The abrasion resistance was evaluated by comparing the change in appearance with the sliding abrasion using a plastic rubber.

Table 1 below shows SiO accompanying the binder when the substrate is a ceramic tile₂-Al₂O₃-N_a/K₂The change of the roasting temperature of the O glass material and the change of the antibacterial property and the wear resistance. (Table 1)

Ceramic tile and SiO as base material₂-Al₂O₃-Na/K₂O glass frit

photocatalyst-TiO₂

No.	1	2	3	4	5
No.	1	2	3	4	5	Calcination temperature (. degree.C.) Difference from softening temperature (. degree. C.) Antibacterial property Wear resistance	700 20 ++ △	780 100 +++ ○	880 200 +++ ◎	980 300 - ◎	1000 320 - ◎

+++: the survival rate of Escherichia coli is below 10%

++: the survival rate of the escherichia coli is more than 10% and less than 30%

+: the survival rate of the escherichia coli is more than 30% and less than 70%

-: the survival rate of the escherichia coli is more than 70 percent

◎ not changing for 40 times of reciprocating

○ scratching and photocatalyst layer (TiO) on 10-40 sliding₂Film) peeling

△ scratching and photocatalyst layer (TiO) on 5-10 sliding₂Film) peeling

X: sliding less than 5 times has scratches, photocatalyst layer (TiO)₂Film) peeling

Here, SiO is used as the binder layer₂-Al₂O₃-Na/K₂The specific gravity of the O frit was 2.4, the film thickness at the time of coating was 200. mu.m, and the softening temperature was 680 ℃. In addition, in Table 1, the obtained TiO₂Of these, Nos. 1 to 3 are anatase type, and the specific gravity is 3.9, and Nos. 4 and 5 are rutile type, and the specific gravity is 4.2.

In Table 1, No.1 was fired at a temperature 20 ℃ higher than the softening temperature of the binder layer, and anatase type TiO forms the lowermost layer of the photocatalytic layer in order to insufficiently reduce the viscosity of the binder layer₂The particles were not sufficiently embedded in the binder, and therefore, in the abrasion resistance test, scratches were generated at 5 to 10 times of sliding, and peeling was observed. This can be interpreted as being resistant toThe photocatalytic activity is excellent in terms of bacteria, and TiO is in anatase form at 300 ℃ or higher₂TG-DTA observation of the sol revealed that the organic components were substantially decomposed, gasified, and adhered to TiO₂The dispersing agent such as the surface treatment agent on the surface is gasified, but the baking temperature is a treatment temperature much higher than this temperature, i.e., 700 deg.CForming a + + excellent value.

No.3-5 was excellent in durability even when the firing temperature was 800 ℃ or higher and 1000 ℃ or lower, and was not changed even in 40 sliding tests or more. The reason for this is considered to be TiO accompanying the surface₂The initial firing of the pellets results in the formation of a neck. In addition, TiO on the surface of the multifunctional material taken out of the roller hearth furnace after cooling and solidifying at 1100 deg.C₂Cracks develop in the layer. From TiO₂TMA measurement of the sample was judged to be accompanied by TiO₂Significant shrinkage of the particle volume is caused by the intermediate stage sintering.

Both of Nos. 4 and 5 had poor antibacterial activity and were-in. Two reasons can be considered. One is TiO₂The particle phase is changed into rutile type, and the other is that the baking temperature is higher than the softening temperature of the binder layer by more than 300 ℃, the viscosity of the binder layer becomes too low, and TiO forming the photocatalyst layer₂The particles are embedded in the binder layer. Cannot be regarded herein as TiO only₂The reason why the particle phase is converted into rutile type. This is because solid rutile TiO₂Is inferior to anatase type TiO₂But the photocatalysis is also active to some extent. For example, directly spraying TiO on porous alumina substrate₂The antibacterial property of the material is + after the sol is roasted at 950 ℃ and cooled and solidified. It can be explained that the calcination temperature is 300 ℃ or more higher than the softening temperature of the binder layer, the viscosity of the binder layer becomes too low, and the TiO constituting the photocatalyst layer₂The particles are embedded in the binder layer, which is also one of the reasons.

Further, the mixed layer of Ti and Si (main component of binder) was observed by elemental analysis of Ti and Si such as EPMA in the cross-sectional direction of the sample, and it was confirmed that the photocatalyst particles TiO₂Is buried.

Example 1 above, i.e. at least photocatalyticThe agent being TiO₂The adhesive layer is SiO₂-Al₂O₃-Na/K₂The following facts were confirmed in the case of O frit.

(1) When the multifunctional material is manufactured under the condition that the roasting temperature is more than 20 ℃ and not more than 300 ℃ higher than the softening temperature of the adhesive layer, the multifunctional material with good antibacterial property and wear resistance can be manufactured. The reason for this is considered to be that the viscosity of the adhesive is adjusted in the above temperature rangeTo make TiO₂A value that can be moderately buried in the binder layer.

(2) Among the multi-functional materials which have been confirmed to be produced in (1), TiO₂The particles are embedded in a binder.

(3) When the firing temperature is 800 ℃ or higher and 1000 ℃ or lower, the wear resistance is excellent and the sliding test is not changed for more than 40 times. Can be considered to accompany TiO₂The constriction formation between the particles produces a strong bond.

Example 2

SiO was formed on the surface of a 100X 5 alumina substrate (alumina purity 96%) by a spray coating method₂-Al₂O₃A binder layer of PbO frit, dried and coated with 15% TiO by spraying₂The sol aqueous solution (same as example 1) was used to form TiO film with a thickness of 0.8. mu.m₂The layer was then heat-baked in a roller hearth furnace at different atmospheric temperatures for each example to laminate the binder layer and TiO₂The substrate of the layer is then cooled and solidified to obtain the multifunctional material.

In Table 2 below, SiO is shown along with the binder when the substrate is alumina₂-Al₂O₃Change in firing temperature, change in antibacterial properties and abrasion resistance of the PbO frit. (Table 2)

Alumina plate (100X 5),

Binder SiO₂-Al₂O₃-PbO glass frit

photocatalyst-TiO₂

No.	6	7	8	9	10
No.	6	7	8	9	10	Calcination temperature (. degree.C.) Difference from softening temperature (. degree. C.) Antibacterial property Wear resistance	560 20 ++ △	580 40 +++ ○	740 200 +++ ○	840 300 ++ ◎	880 320 + ◎

SiO used as the binder in this case₂-Al₂O₃The softening temperature of the-PbO glass was 540 ℃, the specific gravity was 3.8, and the film thickness was 150 μm when coated. In addition, the TiO obtained₂Has been anatase.

In the wear resistance test of table 2, No.6 was peeled after 10 sliding scratches or less, but No.7 and 8 had no scratches even after 10 or more sliding scratches, and No.9 had good results of no scratches even after 40 or more sliding scratches.

No.9 and No.10 were considered to have no scratches even after 40 sliding cycles or more because the firing temperature was 800 ℃ or more and TiO was₂Necking between particles, TiO₂The particles are firmly bonded to each other.

In No.6, the sliding was scratched or peeled off 10 times or less, which is considered to be because the calcination temperature was 20 ℃ higher than the softening temperature of the binder, the viscosity of the binder was not so low, and anatase type TiO constituting the lowermost layer of the photocatalyst layer₂The particles are not sufficiently embedded in the binder layer.

On the contrary, in Nos. 7 and 8, no scratches were found even in 10 or more sliding, which is considered to be because the temperature was not higher than the necking temperature, but the difference between the baking temperature and the binder softening temperature was adjusted so that the viscosity of the binder became TiO₂A value moderately buried in the binder layer.

On the other hand, in the case of a liquid,in the antibacterial test of Table 2, No.6-9 gave good results of + + + or + +, but No.10 was +. This is considered to be because the calcination temperature was 320 ℃ higher than the softening temperature of the binder, and the viscosity of the binder was too low, so that TiO constituting the photocatalyst layer₂The particles are embedded in the binder layer.

Example 3

Mixing SiO₂-Al₂O₃Melting the BaO frit in a mold, cooling to solidify, processing to obtain a 100X 1 glass sheet, and coating 15% TiO on the sheet by spraying₂The sol aqueous solution (same as example 1) was used to form TiO film with a thickness of 0.8. mu.m₂And (3) a layer. This is achieved byThereafter, the glass flake was placed on an alumina substrate (100X 5), heat-fired in a silicon carbide rod furnace at atmosphere temperatures different from example to example, and then cooled to solidify, to obtain a multifunctional material.

Table 3 shows the change in the antibacterial property and the abrasion resistance with the change in the baking temperature of the multifunctional material. (Table 3)

Alumina plate (100X 5),

Binder SiO₂-Al₂O₃-BaO frit

photocatalyst-TiO₂

No.	11	12	13	14
No.	11	12	13	14	Calcination temperature (. degree.C.) Difference from softening temperature (. degree. C.) Antibacterial property Wear resistance	640 20 ++ ×	740 120 +++ ○	840 220 +++ ◎	940 320 - ◎

Here, SiO is used as the binder₂-Al₂O₃Softening temperature of the BaO frit is 620 ℃, specific gravity is 2.8, TiO on multifunctional material₂No.11-13 is anatase type, and No.14 is rutile type.

In the wear resistance test of table 3, No.11 had scratches and was peeled off at 10 or less times of sliding, but No.12 had scratches even at 10 or more times of sliding, and No.13 and 14 had good results of no scratches even at 40 or more times of sliding.

No.13 and 14 had no scratches even after 40 times or more sliding, and it is considered that the reason why the firing temperature was 800 ℃ or more and the temperature was TiO₂Necking between particles, TiO₂The particles are firmly bonded to each other.

No.11 was scratched or peeled off by sliding 10 times or less, and it is considered that the baking temperature was 20 ℃ higher than the softening temperature of the binder, the viscosity of the binder was not sufficiently low, and anatase type TiO constituting the lowermost layer of the photocatalyst layer₂The particles cannot be sufficiently buried in the binder layer.

In contrast, No.12 was not scratched even when it was slid 10 times or more, and it is considered that the difference between the baking temperature and the binder softening temperature was adjusted so that the viscosity of the binder could be adjusted to an appropriate level to make TiO suitable for the neck-down forming temperature, although the baking temperature was not reached₂The value embedded in the binder layer.

On the other hand, in the antibacterial test of Table 3, Nos. 11-13 gave good results of + + + or + +, but No.14 was-. This is believed to be due to two reasons: TiO 2₂Is rutile type, and has roasting temperature 320 deg.c higher than the softening temperature of the adhesive and too low viscosity, and forms the TiO of the photocatalyst layer₂The particles are embedded in a binder layer.

From the above, it was confirmed that TiO was previously coated on the binder₂The method of obtaining the multifunctional material by baking the particles, then pasting the particles on a substrate, and also obtaining the method of obtaining the multifunctional material by coating the substrate with a binder and then coating TiO₂And (4) particles, and the same effect as the method for obtaining the multifunctional material is obtained.

Example 4

An acrylic resin binder was applied to the surface of a 100X 5 polyimide resin substrate, and then 15% TiO was applied by spray coating₂Sol aqueous solution to form TiO with a film thickness of 0.8 μm₂Layer, followed by firing in a nichrome furnace at 150 ℃ to laminate the binder layer and TiO₂A substrate of the layer.

Table 4 below shows the changes in the antibacterial property and the abrasion resistance according to the changes in the baking temperature of the multifunctional material.

(Table 4)

Polyimide resin as base material and acrylic resin as adhesive

photocatalyst-TiO₂Roasting temperature 150 deg.C

No.	15	16
No.	15	16	Antibacterial property Wear resistance	- ○	++ ○

In Table 4, 15% of TiO₂The method of adjusting the sol aqueous solution was changed as follows.

No. 15: the 15% TiO used in example 1 was used as is₂An aqueous sol solution.

No. 16: the aqueous TiCl solution was hydrolyzed at 110-150 ℃ in an autoclave, and then the resultant was adjusted to pH 0.8 with nitric acid, dispersed without using a surface modifier, and then the aggregate-removed substance was used. The spraying is carried out immediately after the removal of the agglomerates.

Here, TiO₂Has a specific gravity of 3.9, the crystal form is anatase type, the specific gravity of the acrylic resin is 0.9,the temperature at which a viscosity corresponding to the softening point of the glass is formed is 70 ℃.

With respect to the wear resistance, no galling occurred even with 10 or more slips under the conditions of nos. 15 and 16. This is considered to be because the difference between the baking temperature and the softening temperature of the binder is within a range that allows the viscosity of the binder to be adjusted to TiO₂A value that can be moderately buried in the binder layer.

On the other hand, with respect to the antibacterial property test, it was found that No.15 is-but No.16 gives a good result of + + and can produce a multifunctional material having antibacterial properties even at 30 ℃ or lower. In DTA-TG, TiO No.15 was used₂The sol had a component which decomposed and evaporated at 350 ℃ of 200 ℃ and no component which was observed in No.16, and thus, it had or had not been coated with TiO₂Of (2) aThe composition is the cause of this difference.

Further, anatase type TiO₂The difference in specific gravity from the acrylic resin was 3, but it was confirmed that TiO constituting the photocatalyst layer was present in this difference in degree₂The particles are not embedded in the binder layer and have excellent antibacterial properties.

Example 5

A binder layer comprising a glass frit or the like having a specific gravity different from that of each example was formed on the surface of a 100X 5 alumina substrate by a spray coating method, dried, and then coated with 15% TiO by a spray coating method₂Sol aqueous solution to form TiO with a film thickness of 0.8 μm₂A layer, followed by laminating the adhesive layer and TiO at an atmospheric temperature of 750 ℃ in a roll-hearth furnace₂And heating and roasting the substrate of the layer, and then cooling and solidifying to obtain the multifunctional material.

Table 5 below shows the changes in the antibacterial properties and abrasion resistance of the multifunctional material depending on the baking temperature. (Table 5)

Alumina plate (100 × 100 × 5) as substrate and TiO as photocatalyst₂

No.	17	18	19	20
No.	17	18	19	20	Kind of the Binder	SiO₂-Al₂O₃-PbO		SiO₂-Al₂O₃-PbO
Specific gravity of binder TiO₂Specific gravity of Softening temperature of glass frit (℃) Calcination temperature (. degree.C.)	5.3 3.9 480 750	3.8 3.9 540 750	2.8 3.9 620 750	2.4 3.9 680 750	Kind of the Binder	SiO₂-Al₂O₃-PbO		SiO₂-Al₂O₃-PbO
	5.3 3.9 480 750	3.8 3.9 540 750	2.8 3.9 620 750	2.4 3.9 680 750	Antibacterial property Wear resistance	++ ×	+++ ○	+++ ○	+++ ○

As for the antibacterial test, the samples No.17-20 all gave good results of +++ respectively. In each sample, the baking temperature is higher than the softening temperature of the softening agent by more than 30 ℃ and lower than 300 DEG CThe viscosity of the binder is adjusted to TiO within a range in which the difference between the baking temperature and the softening temperature of the binder is considered₂A value moderately buried in the binder layer.

With respect to the abrasion resistance, No.17 had scratches after 5 times or less of sliding and was peeled off, but No.18-20 had no scratches even after 10 times or more of sliding.

The reason for this is considered that No.17 is different from others in the specific gravity ratio of the binder TiO₂Has a large specific gravity, and forms anatase type TiO at the lowermost layer of the photocatalyst layer₂The particles are not embedded in the binder layer.

Thus, TiO₂And the specific gravity of the binder, if greater than that of TiO, both affect the wear resistance of the multifunctional material₂The specific gravity of (3) is inferior in abrasion resistance.

Example 6

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which TiO is mixed and stirred by spraying₂Sols and SnO₂And (3) calcining the aqueous solution formed by sol at 750 ℃, cooling and solidifying to obtain the multifunctional material.

In addition, TiO₂The sol concentration is 4-6% by weight, based on NH₃Adjusting the pH of the aqueous solution to 11, TiO₂The grain size of the particles was 0.01. mu.m, SnO₂The grain size of the particles was 0.0035 μm.

The multifunctional material thus produced is comparable to TiO₂And SnO₂Total amount of change SnO₂Amounts (mol ratio), antibacterial property and abrasion resistance tests were performed, and the results are shown in table 6 below.

(Table 6)

Ceramic tile and SiO as base material₂-Al₂O₃-BaO frit

photocatalyst-TiO₂SnO₂(0.0035μm)

No.	21	22	23	24	25
No.	21	22	23	24	25	SnO₂Amount (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ◎	20 +++ ◎	60 ++ ◎	100 - ◎

For the abrasion resistance test, SnO₂The amount of the compound (D) is increased, and since the compound (D) is added in an amount of 10% or more, no scratch occurs even in 40 sliding tests, and no change occurs.

In the antibacterial test, the range of 20% or more is +++, as in the case of no addition, and the range of 60% is limited to ++. If the amount is increased, the TiO on the surface of the substrate is covered₂The probability of the particles becomes high, and the antibacterial property deteriorates and becomes-100%.

Thus, if SnO is used in a molar ratio₂Is added in an amount of TiO₂And SnO₂The total amount of the multifunctional material is 10% or more and 60% or less, preferably 10% or more and 20% or less, and thus a multifunctional material having excellent antibacterial properties and abrasion resistance can be provided.

Here, the abrasion resistance is dependent on SnO₂The amount of (a) is increased due to the mechanism shown below: because of the high temperature of 600 ℃ or higher, SnO₂The vapor pressure is higher than that of TiO₂So that before sintering, the TiO is₂The spacing between the particles 3b is Lo as shown in FIG. 17(a), but in TiO₂The surface of the particle 3 having a positive curvature becomes high in vapor pressure and has a negative curvature, i.e., two TiO₂The surface vapor pressure of the constriction where the particles 3b meet becomes low. The results are shown in FIG. 17(b), which shows the steam pressure ratio of TiO₂High SnO₂Then, the mixture enters the constriction, condenses as shown in FIG. 17(c), and is sintered by the vaporization-condensation mechanism.

When sintering is performed by the vaporization-condensation mechanism, the sintered TiO₂GranulesInterval L of₂The gap was approximately equal to the pre-sintering gap Lo, and therefore, no cracks were generated.

In this way, TiO is bonded by a binder₂In a composite member having a particle layer held on the surface of a base material, TiO on the outermost surface of the particle layer is exposed₂SnO is filled in gaps of the particles₂When the particles are calcined at 600 ℃ or higher, no cracks are generated because TiO can be made₂The necking parts between the particles are bonded, and therefore, the wear resistance is improved.

Comparative example 7

SiO was formed on the surface of a 150-square ceramic tile substrate in the same manner as in example 6₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which the mixed and stirred TiO is applied by spraying₂Sols and SnO₂And (3) calcining the aqueous solution formed by sol at 750 ℃, and cooling and solidifying to obtain the multifunctional material.

In addition, TiO₂The sol concentration is 4-6% by weight, based on NH₃The aqueous solution was adjusted to pH11 and the crystal grain size of the particles was 0.01. mu.m as in example 6, but SnO was used₂The grain size of the particles was 0.008 μm and slightly larger.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test, and the results of comparison with example 6 are shown in table 7 below. (Table 7)

Ceramic tile and SiO as base material₂-Al₂O₃-BaO frit

photocatalyst-TiO₂SnO₂(0.0080 μm), heat treatment 750 ℃ C

No.	26	27	28	29	30
No.	26	27	28	29	30	SnO₂Amount (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ○	20 +++ ○	60 ++ ◎	100 - ◎

As a result, 0.008. mu.m SnO₂The effect of improving the abrasion resistance of the particles is more than that of using 0.0035 μmSnO of₂Weak in grain, to TiO₂And SnO₂The molar ratio of the total amount is about 60% or more, and no scratches and no changes occur even in 40 sliding tests.

For the antibacterial property test, 0.0035 μm SnO was used₂The same applies to the particles ifThe content is in the range of 20% or more, and is + + +, as in the case of no addition, and is limited to 60% or less. If added, the TiO covering the surface of the substrate₂The probability of the particles becomes high, and the antibacterial property deteriorates, and 100% of the particles become-.

Therefore, 0.01 μm TiO is used₂In the case of the pellets, 0.008. mu.m SnO was added₂It is difficult to obtain a multifunctional material excellent in both antibacterial property and abrasion resistance from the particles. The reason is considered to be that SnO is accompanied by₂The particle diameter becomes larger, the vapor pressure becomes smaller, and SnO remaining without vaporization₂When the particle size is 0.008 μm, the particle size is reduced by mixing with TiO₂Interstitial ratio between particles SnO₂Large particles, so SnO₂The particles do not enter the interstices and of course reach the TiO₂The probability of particles becoming higher than the remaining SnO which is not gasified₂SnO at a particle size of 0.0035 μm₂Present in TiO₂In the gaps between the particles, the bonding strength can be improved.

From the above, TiO should be buried₂SnO of interstitial spaces of particles₂Particle size vs. TiO₂The particle diameter is preferably 4/5 or less.

Example 8

Forming SiO on the surface of 150 square ceramic tile base material₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which TiO is applied by spraying₂After sol water solution is roasted at 750 deg.C, the cooled and solidified composite member is coated with SnO by spray coating method₂After the sol water solution is treated by heat at 110 ℃, the multifunctional material is obtained. In this case at TiO₂The same sol as in example 6 was used in an aqueous sol solution, and the sol solution was dissolved in SnO₂The sol used was 0.0035 μm.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test, and the results are shown in table 8 below.

(Table 8)

Ceramic tile and SiO as base material₂-Al₂O₃-BaO frit

Photo catalysisAgent TiO ═ TiO₂、

SnO in interstitial particles₂(0.0035 μm), heat treatment at 750 deg.C/110 deg.C

No.	31	32	33	34	35
No.	31	32	33	34	35	SnO₂Amount (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ○	20 +++ ◎	60 ++ ◎	100 - ◎

For the abrasion resistance test, SnO₂The amount of the compound (D) is increased, and since the compound (D) is added in an amount of 20% (mol ratio) or more, no scratches are generated and no change is caused even in 40 sliding tests.

In the antibacterial test, the range of 20% or more is +++, as in the case of no addition, and the range of 60% is limited to ++. If the amount is increased, TiO on the surface of the substrate is covered₂The probability of the particles becomes high, and the antibacterial property deteriorates, and becomes-100%.

In this test, because of SnO₂The sol was heat-treated at a low temperature of 110 ℃, so that sintering due to the vaporization-condensation mechanism shown in example 6 did not occur. Although the abrasion resistance was improved, it is considered that this is because of the particle diameter ratio of TiO₂SnO with small particle, i.e. large specific surface area and good adsorption capacity₂Particle-embedded TiO₂Interstitial spaces between particles, thereby strengthening TiO₂The particles are bonded to each other.

Example 9

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which TiO is applied by spraying₂After the sol aqueous solution is calcined at 750 ℃, the sol aqueous solution is coated on a composite member obtained by cooling and solidifyingThe copper acetate aqueous solution was dried, and then irradiated with light containing ultraviolet rays to reduce copper ions while being fixed on the photocatalyst layer, to obtain a multifunctional material. Here, the lamp used was a mercury lamp。

The average particle size of Cu fixed on the photocatalyst layer was about 0.004 μm.

The multifunctional materials thus produced were subjected to antibacterial tests and abrasion resistance tests, and the results are shown in table 9. (watch 9)

Ceramic tile and SiO as base material₂-Al₂O₃-BaO frit

photocatalyst-TiO₂、

Interstitial particles of Cu (0.004 μm), heat treatment of 750 ℃/photoreduction

No.	36	37	38	39	40
No.	36	37	38	39	40	Amount of Cu (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ○	20 +++ ◎	60 +++ ◎	100 +++ ◎

The wear resistance test was improved with an increase in the amount of Cu, and since 20% (mol ratio) or more was added, no scratches were found and no change was found even in 40 sliding tests.

In the antibacterial test, when the content of Cu is in the range of 20% or more, it is +++, as in the case where Cu itself has antibacterial activity, and therefore, the antibacterial property is not deteriorated by addition of a large amount of Cu.

However, when the amount of Cu added is small, TiO probably causes₂The photocatalytic action by the particle layer is dominant, and when the amount of Cu added is large, the action by Cu may be considered dominant. When only the action of Cu is expected, Cu is slowly eluted when used in a liquid, and therefore, the life is considered to be shorter than that in the case of no photocatalyst. In addition, if CuThe amount of addition of (2) increases, and the cost of the part also increases. Therefore, it is not considered meaningful to set the Cu amount too much.

According to this example, it has been confirmed that not only SnO₂Such oxides, and metals such as Cu can be buriedTiO₂The particles in the interstices of the particle layer.

Example 10

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which TiO is applied by spraying₂After the sol aqueous solution was calcined at 950 ℃, a copper acetate aqueous solution was coated on the composite member obtained by cooling and curing, and then light containing ultraviolet rays was irradiated to reduce copper ions while fixing on the photocatalyst layer, thereby obtaining a multifunctional material.

In this case, the lamp was a BLB lamp and irradiated for several minutes. TiO 2₂The anatase type phase is changed into the rutile type phase through the heat treatment process. TiO in the course of spraying₂The film thickness of (2) was adjusted to 0.4. mu.m.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test. With respect to the abrasion resistance test, good results were shown in this temperature region even without addition. Even if Cu was added, no scratch was observed and no change was observed in 40 sliding tests as in the case of no addition.

The antibacterial property test is shown in fig. 18. In the absence of addition, because of TiO₂Is rutile type, and is not good +. The antibacterial property is increased by adding Cu. And when the Cu supporting amount is 0.7. mu.g/cm not only in the case of irradiation with BLB lamp but also in the case of no irradiation²Above, the antibacterial activity becomes ++, when the Cu supporting amount is 1.2. mu.g/cm²Above, the antibacterial activity becomes +++.

From the above, in order to provide a multifunctional material excellent in both antibacterial property and abrasion resistance, the amount of Cu supported may be 0.7. mu.g/cm²The concentration of the surfactant is preferably 1.2. mu.g/cm²The above.

However, when the drying process is performed after the copper acetate aqueous solution is applied and before the BLB lamp is irradiated, the amount of Cu supported is dramatically increased. This relationship is shown in fig. 19. This is considered to be because the metal ion concentration in the case of performing the photoreduction is high when the drying is performed.

When the coating amount is optimized, the Cu supporting amount is set toIs the maximum (FIG. 20, FIG. 20 is an example of copper acetate with a Cu concentration of 1 wt.%), and in the case of FIG. 20, in order to make the Cu supporting amount 0.7. mu.g/cm²Above, the coating amount may be 0.2mg/cm²Above, 2.7mg/cm²Hereinafter, the Cu supporting amount is 1.2. mu.g/cm²Above, the Cu coating amount may be 0.3mg/cm²Above, 2.4mg/cm²The following.

Example 11

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 680 ℃ C.), on which TiO is applied by spraying₂After the sol aqueous solution was calcined at 950 ℃, a silver nitrate aqueous solution was applied to the composite member obtained by cooling and solidifying, and the composite member was dried, and then irradiated with light containing ultraviolet rays to reduce silver ions and fix the silver ions on the photocatalyst layer, thereby obtaining a multifunctional material.

The lamp was a BLB lamp and irradiated for several minutes. In addition TiO₂And is converted from anatase to rutile by heat treatment. TiO in the course of spraying₂The film thickness of (2) was adjusted to 0.4. mu.m.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test. With respect to the abrasion resistance, good results were shown in this temperature region even if no addition was made. Even when Ag was added, no scratch was observed and no change was observed in 40 sliding tests as in the case where Ag was not added.

The antibacterial properties are shown in fig. 70. When not added, because of TiO₂Is rutile type and therefore is poor +. When Ag is added thereto, the antibacterial activity is increased. And when the Ag supporting amount is 0.05. mu.g/cm not only when the BLB lamp is irradiated but also when the BLB lamp is not irradiated²Above, the antibacterial activity is ++, and the Ag loading is 0.1. mu.g/cm²Above, the antibacterial activity becomes +++.

Therefore, in order to provide a multifunctional material excellent in both antibacterial property and abrasion resistance, the Ag supporting amount may be 0.05. mu.g/cm²The concentration of the surfactant is preferably 0.1. mu.g/cm²The above.

However, the amount of Ag carried is largeThe color changed from brown to black, and the appearance deteriorated. However, the Ag loading was 1. mu.g/cm²Hereinafter, no coloring is performed.

As described above, the amount of Ag supported may be 0.05. mu.g/cm²Above, 1 mu g/cm²Above, more preferably 0.1. mu.g/cm²Above, 1 mu g/cm²The following.

Example 12

At this time, the irradiation lamp was a BLB lamp for several minutes. In addition TiO₂And is converted from anatase to rutile by heat treatment.

Modification of the thus produced multifunctional Material with TiO₂The film thickness of (a) was subjected to an abrasion resistance test, an antibacterial property test and a stain resistance test.

The wear resistance test showed good results within 2 μm of the test, and no change was observed even in 40 sliding tests without scratching.

The antibacterial property test showed that the film thickness was +++, when it was 0.1 μm or more, and +++, when it was 0.2 μm or more. Thus, TiO₂The film thickness of (B) may be 0.1 μm or more, preferably 0.2 μm or more.

Example 13

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃) on which an aqueous zinc chloride solution or TiO is applied by spraying₂Drying the sol aqueous solution, coating silver nitrate aqueous solution, irradiating with ultraviolet light to reduce silver ions, fixing on the photocatalyst layer, and dryingRoasting at 900-1000 deg.c, cooling and solidifying to obtain the multifunctional material.

In this case, the lamp was a BLB lamp and irradiated for several minutes. In addition TiO₂Heat treated from anataseThe mineral phase is transformed into rutile. Further, since Ag fixed to the surface changes from black to white with heat treatment, it is considered that Ag becomes silver oxide during firing. However, the attachment and fixation of Ag were discretely accomplished, and it was observed that almost no growth of Ag particles was observed before and after the firing.

The multifunctional material thus produced was subjected to an antibacterial test and an abrasion resistance test.

With respect to the abrasion resistance test, good results were shown even without addition in this temperature zone. Even when Ag was added, no scratches were observed and no change was observed in the sliding test of 40 times, as in the case where Ag was not added.

The antibacterial property test is shown in FIG. 70, and when no addition is made, the antibacterial property test is due to TiO₂Is not good because it is rutile type. When Ag is added thereto, the antibacterial activity is increased.

Example 14

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which TiO is applied by spraying₂A composite member obtained by dissolving the above aqueous solution in a sol, calcining at 900-1000 deg.C, cooling and solidifying, coating with an aqueous solution of silver nitrate, irradiating with light containing ultraviolet rays to reduce silver ions and fix them on the photocatalyst layer, and applying a coating of 0.1cc/cm²The multifunctional material is obtained by coating 0.1mol/L KI aqueous solution and then irradiating the solution with ultraviolet rays for about 5 seconds. The amount of Ag carried at this time was 2. mu.g/cm²。

Since the flow rate is 0.1cc/cm²The multifunctional material is coated with 0.1mol/L KI aqueous solution and then irradiated with ultraviolet rays for about 5 seconds, and the original black multifunctional material is decolorized into white and the appearance is improved.

Example 15

On the surface of 150 square ceramic tile base material a layer made of SiO₂-Al₂O₃A binder layer of BaO frit (softening temperature 620 ℃ C.), on which TiO is applied by spraying₂Calcining the sol aqueous solution at 820 deg.C, cooling and solidifying, placing the obtained multifunctional material in a slant manner, irradiating the multifunctional material with ultraviolet light, and placing the multifunctional materialThe bath water collected from public bathing places was continuously dropped, and the change of the bath water was observed. For comparison with the same device, the photocatalyst layer was dropped on the base material without the photocatalyst layer. After 14 days, it was observed that the bath water dropped on the above-mentioned multifunctional material was not particularly different in turbidity from the bath water dropped on the base material on which the photocatalyst layer was not provided, but was different in sewer water odor. In contrast to the case where the bath water dropped on the base material on which the photocatalyst layer was not provided had a considerable odor of the sewage water and sludge-like slime and organic precipitates were observed on the base material, none of the bath water dropped on the above-mentioned multifunctional material was observed. Through the above simulation tests, it can be considered that the multifunctional material can be used as artificial waterfalls and stone pavers of fountains in water circulation modes of parks, department stores and the like.

As is apparent from the above description, in order to fix the photocatalyst particles by the binder layer composed of a material having a lower softening temperature than the base material, the photocatalyst particles are substantially in a state where the surface thereof is exposed to the outside, and the photocatalytic effect can be sufficiently exhibited, particularly, because the photocatalyst particles constituting the surface portion of the photocatalyst layer are not embedded in the binder layer. Further, among the photocatalyst particles, the particles constituting the lower layer of the photocatalyst layer are partially embedded in the binder layer, so that the holding power of the photocatalyst layer is greatly improved and peeling or the like is less likely to occur.

Fig. 21 is a process diagram showing a manufacturing process of another example in which a thermoplastic material such as inorganic glass or a thermoplastic resin is used as a substrate 1, and a photocatalyst layer 2 is directly formed on the surface of the thermoplastic substrate 1.

That is, as shown in FIG. 21(a), a thermoplastic substrate 1 is prepared, and then as shown in FIG. 21(b), Ti is formed on the surface of the thermoplastic substrate 1O₂Photocatalyst layer 2 composed of photocatalyst particles such as particles. Thereafter, as shown in fig. 21(c), the lower layer of the photocatalyst layer 2 on the thermoplastic substrate side is deposited on the thermoplastic substrate by heat treatment, and is embedded in the thermoplastic substrate by solidification and firmly held. The photocatalyst particles 3 constituting the surface layer in contact with the air in the photocatalyst layer 2 are bonded by potential energy, intermolecular force, or sintering.

The preferred conditions and the like of the present embodiment are the same as those of the above embodiment, but specific embodiments are described below.

Example 16

SiO in 150 squares₂-Al₂O₃-Na/K₂Coating 15% TiO on the surface of glass substrate composed of O by spray coating₂Sol aqueous solution to form TiO with a film thickness of 0.8 μm₂Layer, then, TiO will be laminated₂The glass substrate of the layer is put into a ceramic mold with good mold release, heated and roasted in a roller hearth furnace at different atmosphere temperatures according to different examples, and then cooled and solidified to obtain the multifunctional glass.

Here, the term "TiO"₂The sol aqueous solution is prepared in the following way: will be such as TiCl₄Hydrolyzing in an autoclave at 100-200 deg.C to obtain anatase TiO with grain size of 0.007-0.2 μm₂Adding the TiO compound to₂Dispersing in acidic aqueous solution such as nitric acid and hydrochloric acid or alkaline aqueous solution such as ammonia to several to tens of percent in a sol state; in order to improve dispersibility, the surface treatment agent triethanolamine, organic alkali such as trimethylolamine, pentaerythritol, trimethylolpropane, etc. are added in an amount of 0.5% or less to obtain TiO₂An aqueous sol solution. In addition, TiO₂The particle size of the sol was obtained by image processing by SEM observation, and the crystal particle size was calculated from the integral width of powder X-ray diffraction.

The coating method is performed by a spray coating method, but it is expected that similar results can be obtained by a dip coating method or a spin coating method.

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

As for the antibacterial activity, the bactericidal effect against Escherichia coli (Escherichia coli W3110 strain) was tested. 0.15ml of a bacterial solution (1-5X 10) was dropped onto the outermost surface of a multifunctional glass previously sterilized with 70% ethanol⁴CFU) placed on a glass plate (10 × 10cm) and attached to the outermost surface of the substrate as a sample. After 30 minutes of irradiation with a white lamp (3500 lux), the irradiated sample and the bacterial solution of the sample held under the light-shielding condition were wiped with sterilized cotton yarn, and the resultant was collected in 10ml of physiological saline to determine the survival rate of bacteria as an evaluation index.

The abrasion resistance was evaluated by comparing the change in appearance by sliding abrasion using a plastic rubber.

The following Table 10 shows the use of SiO₂-Al₂O₃-Na/K₂The glass base material consisting of O has the antibacterial property and the wear resistance changed along with the change of the roasting temperature. (watch 10)

Substrate SiO₂-Al₂O₃-Na/K₂O glass

photocatalyst-TiO₂

The survival rate of Escherichia coli is less than 10% ++, more than 10% and less than 30% +, more than 30% and less than 70% +, more than 70% and ◎ for 40 timesNo change ○, sliding 10-40 times with scratches, photocatalyst layer (TiO)₂Film) peeling △ scratching and photocatalyst layer (TiO) with sliding 5-10 times₂Membrane) peeling x: sliding less than 5 times has scratches, photocatalyst layer (TiO)₂Film) peeling

Here, SiO₂-Al₂O₃-Na/K₂The specific gravity of the glass substrate composed of O was 2.4, and the softening temperature was 680 ℃. In Table 10, the obtained TiO₂No.1 to 3 are anatase type, and the specific gravity is 3.9, No.4, 5 are rutile type, and the specific gravity is 4.2.

In Table 10, the firing temperature of No.1 is higher than the softening temperature of the glass substrate by only 20 ℃,since the viscosity of the glass substrate cannot be sufficiently reduced, anatase TiO constituting the lowermost layer of the photocatalyst layer₂The particles were not sufficiently embedded in the glass substrate, and therefore, in the abrasion resistance test, there was scratches at 5 to 10 times of sliding, and peeling had occurred. In addition, the photocatalyst is also an anatase type having excellent photocatalytic activity; and to TiO at above 300 DEG C₂TG-DTA observation of the sol revealed that the organic components were substantially decomposed, gasified, and adhered to TiO₂The surface treatment agent and other dispersant on the surface are gasified, but the baking temperature is 700 ℃ and is a heat treatment temperature considerably higher than this temperature, so the antibacterial property is a good value of + +.

No.3-5 had a baking temperature of 800 ℃ or higher and 1000 ℃ or lower, but the wear resistance did not change even in 40 sliding tests or more. Is extremely good. The reason for this is considered to be TiO accompanying the surface₂Initial firing of the pellets produces a constriction. In addition, TiO on the surface of the multifunctional glass taken out of the roller hearth furnace after cooling and solidifying at 1100 DEG C₂Cracks develop in the layer. This is from TiO₂TMA measurement of the sample was judged to be accompanied by TiO₂By intermediate sintering with significant volume shrinkage of the particles.

The antibacterial properties of both Nos. 4 and 5 were "poor". This can be considered for two reasons: one of which is TiO₂The particle phase is changed into rutile type, the other is that the roasting temperature is 300 ℃ higher than the softening temperature of the glass substrate,the viscosity of the glass substrate is too low, and TiO constituting the photocatalyst layer₂The particles are embedded in the glass substrate. TiO alone cannot be considered here₂The reason why the particle phase is converted into rutile type. This is because even in rutile TiO form₂Medium, also inferior to anatase, but also has some degree of photocatalytic activity. For example, directly spraying TiO on porous alumina substrate₂The antibacterial property of the sol is + after the sol is baked at 950 ℃ and cooled and solidified. This is interpreted to mean that the firing temperature is 300 ℃ higher than the softening temperature of the glass substrate, the viscosity of the glass substrate is too low, and TiO constituting the photocatalyst layer is formed₂The particles are embedded in the glass substrate, which is yet another reason.

Further, the photocatalyst particles were confirmed by elemental analysis of Ti and Si (main components of the glass substrate) such as EPMA in the cross-sectional direction of the sample, observing a layer in which Ti and Si are mixedTiO₂Is buried.

Example 16 above, where at least the photocatalyst is TiO₂The glass substrate is made of SiO₂-Al₂O₃-Na/K₂O, the following fact has been confirmed.

(1) When the multifunctional glass is produced under the conditions that the roasting temperature is 20 ℃ higher than the softening temperature of the glass base material and is not higher than 300 ℃, the multifunctional glass with good antibacterial property and wear resistance can be produced. The reason for this is considered to be that the viscosity of the glass substrate is adjusted to TiO within the above temperature range₂A value moderately buried in the glass substrate.

(2) In the multifunctional glass produced in (1), TiO was confirmed₂The particles are embedded in the glass substrate.

(3) When the firing temperature is 800 ℃ or higher and 1000 ℃ or lower, the abrasion resistance is extremely good without change even in 40 sliding tests. Can be considered to follow TiO₂The formation of a constricted portion between the particles results in a strong bond.

Example 17

In the form of SiO₂-Al₂O₃Coating 15% TiO on the surface of a 100X 5 glass substrate consisting of-PbO by spraying₂The sol aqueous solution (same as in example 16) was used to form TiO film with a thickness of 0.8. mu.m₂Layer, then, TiO will be laminated₂The glass substrate of the layer is put into a ceramic mold with good mold release, heated and roasted in a roller hearth furnace at different atmosphere temperatures according to different examples, and then cooled and solidified to obtain the multifunctional glass.

In the following Table 11, SiO is used₂-Al₂O₃The antibacterial property and the wear resistance of the glass substrate consisting of PbO are changed along with the change of the baking temperature.

(watch 11)

Substrate SiO₂-Al₂O₃-PbO glass

photocatalyst-TiO₂

No.	6	7	8	9	10
No.	6	7	8	9	10	Calcination temperature (. degree.C.) Difference from softening temperature (. degree. C.) Antibacterial property Wear resistance	560 20 ++ △	580 40 +++ ○	740 200 +++ ○	840 300 ++ ◎	860 320 + ◎

Here, SiO₂-Al₂O₃The softening temperature of the glass substrate consisting of-PbO was 540 ℃ and the specific gravity was 3.8, and the obtained TiO₂The crystalline form of (a) is anatase.

In the wear resistance test of table 11, No.6 was scratched and peeled off at 10 or less sliding times, but No.7 and 8 were scratched even at 10 or more sliding times, and No.9 and 10 were good results of no scratching even at 40 or more sliding times.

No.9 and No.10 had no rubbing even after 40 times or more of slidingThe reason for this is considered to be that the sintering temperature is 800 ℃ or higher, and therefore, the sintering temperature is higher than that of TiO₂Necking the TiO particles₂The particles are firmly bonded to each other.

No.6 was scratched or peeled off at 10 sliding or less times, and it is considered that the baking temperature was 20 ℃ higher than the softening temperature of the glass substrate, and the viscosity of the glass substrate could not be sufficiently lowered, and anatase type TiO constituting the photocatalyst layer₂The particles are not sufficiently embedded in the glass substrate.

On the contrary, in Nos. 7 and 8, no scratch was observed even in 10 or more sliding, and it is considered that the temperature for forming the neck-in was not reached, but the firing temperature and the softening temperature of the glass substrate wereThe difference is adjusted so that the viscosity of the glass substrate is such that TiO₂A value moderately buried in the glass substrate.

On the other hand, in the antibacterial property test in Table 11, sample No.6-9 gave good results of + + + or + +, but sample No.10 gave + values. This is considered to be because the calcination temperature was 320 ℃ higher than the softening temperature of the glass substrate, the viscosity of the glass substrate was too low, and TiO constituting the photocatalyst layer₂The particles are embedded in the glass substrate.

Example 18

In SiO₂-Al₂O₃Coating 15% TiO on the surface of 100X 5 glass substrate composed of-BaO by spray coating₂The sol aqueous solution (same as in example 1) was used to form TiO film with a thickness of 0.8. mu.m₂And (3) a layer. Then, TiO is laminated₂And (3) putting the glass substrate of the layer into a ceramic die with good demoulding performance, heating and roasting in a nickel-chromium wire furnace at different atmosphere temperatures according to different examples, and then cooling and solidifying to obtain the multifunctional glass.

The following table 12 shows the changes in the antibacterial property and the abrasion resistance according to the changes in the firing temperature of the multifunctional glass. (watch 12)

Substrate SiO₂-Al₂O₃-BaO glass

photocatalyst-TiO₂

Here, SiO₂-Al₂O₃The softening temperature of the glass substrate of the-BaO composition is 620 c,TiO on multifunctional glass with specific gravity of 2.8₂No.11-13 is anatase type, and No.14 is rutile type.

In the wear resistance test of table 12, No.11 was scratched and peeled off at 5 or less times of sliding, but No.12 was scratched even at 10 or more times of sliding, and No.13 and 14 were good results of no scratching even at 40 or more times of sliding.

No.11 was scratched or peeled off at 10 sliding or less times, and it is considered that the baking temperature was 20 ℃ higher than the softening temperature of the glass substrate, the viscosity of the glass substrate was not sufficiently low, and anatase type TiO constituting the lowermost layer of the photocatalyst layer₂The particles are not sufficiently embedded in the glass substrate.

In contrast, No.12 had no scratches even after 10 or more sliding movements, but it is considered that the difference between the firing temperature and the softening temperature of the glass substrate was adjusted so that the viscosity of the glass substrate could make TiO, although the temperature did not reach the temperature for forming the neck part₂The particles are moderately buried in the glass substrate.

On the other hand, in the antibacterial test in Table 12, samples 11-13 gave good results of ++++ or + +, but sample 14 gave a value. This is believed to be due to two reasons: one is TiO₂Rutile type, or a firing temperature 320 ℃ higher than the softening temperature of the glass substrate, and low viscosity of the glass substrate, and TiO constituting the photocatalyst layer₂The particles are embedded in the glass substrate.

Example 19

On the surface of a glass substrate of 100X 5, which was different in specific gravity depending on the examples, 15% of TiO was coated by a spray method₂Sol aqueous solution to form TiO with a film thickness of 0.8 μm₂Layer, then, TiO will be laminated₂The glass substrate is put into a ceramic mold with good demolding property, inAnd (3) heating and roasting in a roller hearth furnace at the atmosphere temperature of 750 ℃, and then cooling and solidifying to obtain the multifunctional glass.

Table 13 below shows changes in the antibacterial property and the abrasion resistance according to changes in the specific gravity of the glass substrate of the multifunctional glass. (watch 13)

photocatalyst-TiO₂

No.	15	16	17	18
No.	15	16	17	18	Kind of glass substrate	SiO₂-Al₂O₃-PbO		SiO₂-Al₂O₃-PbO
Specific gravity of glass substrate TiO₂Specific gravity of Softening temperature of glass substrate (℃) Calcination temperature (. degree.C.)	5.3 3.9 480 750	3.8 3.9 540 750	2.8 3.9 620 750	2.4 3.9 680 750	Kind of glass substrate	SiO₂-Al₂O₃-PbO		SiO₂-Al₂O₃-PbO
	5.3 3.9 480 750	3.8 3.9 540 750	2.8 3.9 620 750	2.4 3.9 680 750	Antibacterial property Wear resistance	++ ×	+++ ○	+++ ○	+++ ○

As for the antibacterial test, the samples Nos. 15 to 18 all gave good results of +++ respectively. This is considered to be because the firing temperature is higher than the softening temperature of the glass substrate by 30 ℃ to 300 ℃ in each case, and the difference between the firing temperature and the softening temperature of the glass substrate is adjusted so that the viscosity of the glass substrate is adjusted to make TiO compatible₂A value moderately buried in the glass base material.

With respect to the abrasion resistance, No.15 had scratches and was peeled off after sliding 5 times or less, and No.16 to 18 had no scratches even after sliding 10 times or more.

The reason for this is considered to be that No.15 is different from others in the specific gravity ratio of the glass substrate TiO₂Anatase type TiO of large specific gravity constituting the lowermost layer of the photocatalyst layer₂Particles are not sufficiently embedded in the glass substrate

Thus, it is clear that TiO₂And the specific gravity of the glass substrate is larger than that of TiO so as to influence the wear resistance of the multifunctional glass₂The specific gravity of (b) deteriorates the abrasion resistance.

Example 20

SiO in 150 squares₂-Al₂O₃Coating TiO on a glass substrate having a BaO composition (softening temperature 620 ℃ C.) by spray coating₂Sols and SnO₂And mixing and stirring the sol to obtain an aqueous solution, then roasting at 750 ℃, cooling and solidifying to obtain the multifunctional glass.

TiO₂The sol concentration is 4-6% by weight, based on NH₃The aqueous solution was adjusted to pH11, TiO₂Grains of particlesParticle size 0.01 μm, SnO₂The grain size of the particles was 0.0035 μm.

For the multifunctional glass thus produced, the variation is relative to TiO₂And SnO₂Sum of various SnO₂The amounts (mol ratio) of the components were measured, and the results of the tests on the antibacterial property and the abrasion resistance were shown in table 14 below. (watch 14)

Substrate SiO₂-Al₂O₃-BaO glass

photocatalyst-TiO₂SnO₂(0.0035μm)

No.	19	20	21	22	23
No.	19	20	21	22	23	SnO₂Amount (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ◎	20 +++ ◎	60 ++ ◎	100 - ◎

For the abrasion resistance test, SnO₂The amount of the compound (D) is increased, and the compound (D) is added in an amount of 10% or more, so that the compound (D) is free from scratches and does not change even in 40 sliding tests.

In the antibacterial test, the content of the compound (c) is 20%, which is equal to + + +, when the content is 60%, which is not added. If added thereon, the TiO on the surface of the glass substrate is covered₂The probability of the particles becomes high, and the antibacterial property becomes poor to 100%.

Thus, according to SnO₂The amount of the compound added is based on the amount of TiO₂And SnO₂The total molar ratio of (a) to (b) is 10% to 60%, preferably 10% to 20%, and thus a multifunctional glass having excellent antibacterial properties and abrasion resistance can be provided.

Here, the abrasion resistance is dependent on SnO₂The increase in the amount of (b) is caused by the mechanism illustrated in FIG. 17.

Thus, TiO is made to pass through the glass substrate₂In the composite member in which the particle layer is held on the surface of the glass substrate, the outermost surface is exposedOf TiO 2₂If the particles are filled with SnO₂The particles, when calcined at temperatures above 600 ℃, do not crack because they enable the TiO to be sintered₂The grains are bonded at the constricted portions, and therefore, the wear resistance is improved.

Comparative example 21

SiO in 150 squares as in example 20₂-Al₂O₃Coating TiO on the surface of a glass substrate having a composition of-BaO (softening temperature 620 ℃ C.) by a spray coating method₂Sols and SnO₂And mixing and stirring the sol to obtain an aqueous solution, then roasting at 750 ℃, cooling and solidifying to obtain the multifunctional glass.

TiO₂The sol concentration is 4-6% by weight, based on NH₃The aqueous solution was adjusted to pH11, and the grain size of the particles was 0.01. mu.m, as in example 5, except that SnO₂The grain size of the particles was 0.008. mu.m or more.

The antimicrobial property and abrasion resistance of the multifunctional glass thus obtained were tested, and the results of comparison with example 5 are shown in table 15 below.

(watch 15)

Substrate SiO₂-Al₂O₃-BaO glass

photocatalyst-TiO₂SnO₂(0.0080 μm), heat treatment 750 ℃ C

No.	24	25	26	27	28
No.	24	25	26	27	28	SnO₂Amount (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ○	20 +++ ○	60 ++ ◎	100 - ◎

As a result, 0.008. mu.m SnO₂The effect of improving the abrasion resistance of the particles is better than that of using SnO with the particle size of 0.0035 mu m₂Weak in the case of particles, relative to TiO₂Particles and SnO₂When the mol ratio of the total amount of the particles was gradually 60% or more, the particles were not subjected to the 40-time sliding testScratching was not altered.

For the antibacterial property test, 0.0035 μm SnO was used₂Similarly to the case of the particles, when the content is in the range of 20%, it is + + +, similarly to the case of no addition, and when the content is 60% or less, it is limited to + +. If added thereon, the TiO on the surface of the glass substrate is covered₂The probability of the particles becomes high, and the antibacterial property deteriorates to 100%.

Thus, 0.01 μm TiO is used₂In the case of the pellets, 0.008. mu.m SnO was added₂And particles, it is difficult to obtain a multifunctional glass having excellent antibacterial properties and abrasion resistance. The reason for this is considered to be that SnO₂The vapor pressure of the particles becomes smaller as the particle diameter becomes larger, and SnO remaining without vaporization₂When the particle size is 0.0035 μm, it is present in TiO₂In the gaps between particles, the bonding strength can be improved, and in contrast, SnO₂Particle size of 0.008 μm with TiO₂Between the particlesGap phase ratio, SnO₂Large in size, so Sn₂The O particles do not enter the gap and naturally reach the TiO₂The probability of particles becoming larger.

From the above, it can be seen that TiO should be buried₂SnO of particle spacing₂The particle size is ideally relative to TiO₂The particle diameter is 4/5 or less.

Example 22

SiO in 150 squares₂-Al₂O₃Coating TiO on the surface of a glass substrate having a composition of-BaO (softening temperature 620 ℃ C.) by spray coating₂Sol water solution, then roasting at 750 deg.C, coating SnO on the cooled and solidified composite member by spray coating method₂After the sol water solution is treated by heat at 110 ℃, the multifunctional glass is obtained. At this time, TiO₂As the aqueous sol solution, SnO similar to example 5 was used₂The sol used was 0.0035 μm.

The multifunctional glass thus produced was subjected to antibacterial property and abrasion resistance tests, and the results thereof are shown in table 16 below. (watch 16)

Substrate SiO₂-Al₂O₃-BaO glass

photocatalyst-TiO₂、

No.	29	30	31	32	33
No.	29	30	31	32	33	SnO₂Amount (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ○	20 +++ ◎	60 ++ ◎	100 - ◎

For the abrasion resistance test, SnO₂The amount of the compound (D) is increased, and since the compound (D) is added in an amount of 20% (mol ratio) or more, no scratches and no change occur even in 40 sliding tests.

In the antibacterial test, the antibacterial activity is +++, as in the case of no addition, when the antibacterial activity is 20%, and is limited to ++, when the antibacterial activity is 60%. If further added, the TiO on the surface of the glass substrate is masked₂The probability of the particles becomes high, and the antibacterial property deteriorates to 100%.

In this test, because of SnO₂The sol was heat-treated at a low temperature of 110 ℃, so that sintering due to the vaporization-condensation mechanism shown in example 5 did not occur. Although the abrasion resistance was improved, it is considered that this is due to the particle diameter ratio of TiO₂SnO with small particle, i.e. large specific surface area and good adsorbability₂Particle-embedded TiO₂Interstitial spaces between the particles, thereby strengthening TiO₂The particles are bonded to each other.

Example 23

SiO in 150 squares₂-Al₂O₃Coating TiO on a glass substrate of the composition-BaO (softening temperature 620 ℃ C.) by spraying₂And calcining the sol aqueous solution at 750 ℃, coating a copper acetate aqueous solution on the cooled and solidified composite member, drying, and then irradiating light containing ultraviolet rays to reduce copper ions and fix the copper ions on the photocatalyst layer to obtain the multifunctional glass. In thatThe lamp uses a mercury lamp.

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

The results of the antibacterial property and abrasion resistance tests of the multifunctional glass thus produced are shown in table 17 below. (watch 17)

Substrate SiO₂-Al₂O₃-BaO glass

photocatalyst-TiO₂、

SnO in interstitial particles₂(0.004 μm), heat treatment 750 ℃/photoreduction

No.	34	35	36	37	38
No.	34	35	36	37	38	Amount of Cu (mol%) Antibacterial property Wear resistance	0 +++ ○	10 +++ ○	20 +++ ◎	60 +++ ◎	100 +++ ◎

The wear resistance was improved with an increase in the amount of Cu, and since 20% (mol ratio) or more was added, no scratches were observed and no change was observed even in 40 sliding tests.

In the antibacterial test, when the content is in the range of 20% or more, it is +++, as in the case where no additive is added, and since Cu itself has antibacterial activity, the antibacterial property is not deteriorated by the addition of a large amount.

However, it is considered that TiO probably caused the addition amount of Cu to be small₂The photocatalytic action by the particle layer is dominant, and when the amount of Cu added is large, the action by Cu is dominant. When only the action of Cu is desired, it is considered that Cu is slowly eluted when used in a liquid, and therefore, the life is shorter than that in the case of no photocatalyst. Further, if the amount of Cu added is large, the cost of this portion is also high. Therefore, it is not meaningful to set the amount of Cu excessively.

It has been demonstrated by this example that₂Such oxides, and metals such as Cu can also be buried TiO₂The particles in the interstices of the particle layer.

Example 24

At 150 squares of SiO₂-Al₂O₃BaO composition (softening temperature 620 ℃ C.) structureCoating TiO on the surface of the glass substrate by a spraying method₂And (3) calcining the sol aqueous solution at 950 ℃, coating a copper acetate aqueous solution on the cooled and solidified composite member, and then irradiating light containing ultraviolet rays to reduce copper ions while fixing on the photocatalyst layer, thereby obtaining the multifunctional glass.

In this case, the lamp was a BLB lamp and irradiated for several minutes. TiO 2₂And the anatase type phase is changed into the rutile type phase through heat treatment. TiO 2₂The film thickness of (2) was adjusted to 0.4. mu.m during the spraying.

The multifunctional glass thus produced was subjected to antibacterial and abrasion resistance tests. With respect to the abrasion resistance test, good results were shown in this temperature region even without addition. Even if Cu was added, no scratch was observed and no change was observed even in the sliding test of 40 times, as in the case of no addition.

The antibacterial property test is shown in fig. 22. When not added, due to TiO₂Is rutile type and therefore poor +. When Cu is added thereto, the antibacterial properties are improved. When the lamp is not irradiated, but irradiated with BLB light, the amount of Cu carried is 0.7. mu.g/cm²Above, the antibacterial activity is ++, and if the Cu supporting amount is 1.2. mu.g/cm²The antibacterial activity becomes +++.

As can be seen from the above, in order to provide a multifunctional glass excellent in both antibacterial property and abrasion resistance, the Cu supporting amount may be 0.7. mu.g/cm²More preferably 1.2. mu.g/cm²。

However, when the drying process is performed after the copper acetate aqueous solution is applied and before the BLB lamp is irradiated, the Cu supporting amount is dramatically increased. This relationship is shown in fig. 23. This is considered to be because the metal ion concentration in the case of carrying out the photo-reduction is high in the drying.

In addition, when the Cu coating amount is optimized, the Cu supporting amount is maximized (fig. 24, an example of copper acetate with a Cu concentration of 1 wt%), and in fig. 24, the Cu supporting amount is set to 0.7μg/cm²As described above, the coating amount may be 0.2mg/cm²Above, 2.7mg/cm²Hereinafter, the Cu supporting amount is 1.2. mu.g/cm²As described above, the coating amount may be 0.3mg/cm²Above, 2.4mg/cm²The following.

Example 25

SiO in 150 squares₂-Al₂O₃Coating TiO on the surface of a glass substrate having a composition of-BaO (softening temperature: 680 ℃ C.) by spray coating₂And (3) calcining the sol aqueous solution at 950 ℃, coating a silver nitrate aqueous solution on the composite member obtained by cooling and solidifying, drying, irradiating light containing ultraviolet rays, reducing silver ions, and fixing on the photocatalyst layer to obtain the multifunctional glass.

At this time, the lamp was irradiated with BLB light for several minutes. In addition TiO₂And is converted from anatase to rutile by heat treatment. TiO 2₂The film thickness was adjusted to 0.4 μm during spraying.

The multifunctional glass thus produced was subjected to antibacterial and abrasion resistance tests. With respect to the abrasion resistance, good results were obtained in this temperature region even without addition. Even if Ag was added, no scratch was observed and no change was observed even in 40 sliding tests, as in the case where Ag was not added.

The antibacterial property test is shown in fig. 25. When not added, due to TiO₂Is rutile type and therefore poor +. Addition of Ag to the composition improves the antibacterial activity. And when the Ag content is 0.05. mu.g/cm not only during irradiation with BLB lamp but also during non-irradiation²Above, the antibacterial activity becomes ++, when the Ag supporting amount is 0.1. mu.g/cm²The antibacterial property becomes +++.

Therefore, in order to provide a multifunctional glass having excellent antibacterial properties and abrasion resistance, the Ag loading amount may be 0.05. mu.g/cm²The concentration of the surfactant is preferably 0.1. mu.g/cm²The above.

However, when the amount of Ag carried is large, the color turns dark from brown, and the appearance deteriorates. However, the Ag loading was 1. mu.g/cm²Hereinafter, the coloring is not performed.

As can be seen from the above, the Ag loading may be 0.05. mu.g/cm²Above, 1 mu g/cm²Hereinafter, the concentration of the surfactant is preferably 0.1. mu.g/cm²Above, 1 mu g/cm²The following.

Example 26

At 150 squares of SiO₂-Al₂O₃Coating TiO on the surface of a glass substrate having a composition of-BaO (softening temperature: 680 ℃ C.) by spray coating₂Aqueous sol solution, then at 950 deg.CThe composite member obtained by cooling and solidifying is baked, coated with a silver nitrate aqueous solution, dried, and then irradiated with light containing ultraviolet rays to reduce silver ions and fix the silver ions on the photocatalyst layer, thereby obtaining the multifunctional glass.

At this time, the lamp was irradiated with BLB light for several minutes. In addition, TiO₂And the anatase type phase is changed into the rutile type phase through heat treatment.

For the multifunctional glass thus produced, TiO was changed₂The film thickness of (a) was subjected to an abrasion resistance test, an antibacterial property test and a stain resistance test.

The wear resistance test showed good results in the range where the test film thickness was within 2 μm, and no scratch was observed and no change was observed even in 40 sliding tests.

The antibacterial property test showed that the film thickness was +++, and 0.2 μm or more. Thus TiO₂The film thickness of (B) may be 0.1 μm or more, preferably 0.2 μm or more.

As is apparent from the above description, in order to fix the photocatalyst particles on the thermoplastic substrate, particularly, in order to prevent the photocatalyst particles constituting the surface layer portion of the photocatalyst layer from being embedded in the thermoplastic substrate, the photocatalyst particles are substantially in a state in which the surfaces thereof are exposed to the outside, and the photocatalytic effect can be sufficiently exhibited. Further, since a part of the photocatalyst particles constituting the lower layer of the photocatalyst layer is embedded in the thermoplastic base material, the holding power of the photocatalyst is greatly improved, and peeling or the like is less likely to occur.

FIGS. 26 and 27 are conceptual diagrams of the basic distribution of the multifunctional material observed in the cross-sectional direction by an EPMA (Electron Beam micro analyzer). As is clear from these figures, the concentration of the component constituting the photocatalyst layer 2 is substantially constant in the region (region a) from the surface in contact with the air, and thereafter the component constituting the photocatalyst layer is decreased. Further, the components constituting the amorphous layer (binder layer) are not present or present only in a small amount on the surface, and the concentration increases as the components enter the inside. When the film thickness reaches a constant level, the component concentration is substantially constant (region B). The a region is defined herein as a photocatalyst layer, the B region is defined as an amorphous layer, and the middle C region thereof is defined as an intermediate layer. However, fig. 26 is a conceptual diagram for convenience of explanation, and as shown in fig. 27, the concentration fluctuation is often caused in the portion having a constant concentration described in fig. 26 due to the manufacturing process. In this case, as shown in fig. 27, the concentration minimum value portions reaching the regions (a 'region, B' region) corresponding to the certain regions are regarded as boundaries of the a 'region and the C' region, and the B 'region and the C' region, respectively.

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

The thickness of the intermediate layer can be varied by controlling the speed and possibly time of movement of the photocatalyst particles into the softened amorphous layer. The moving speed can be controlled by the difference in specific gravity between the photocatalyst particles and the amorphous layer, the calcination temperature, the atmospheric pressure, and the like. In addition, the time over which movement is possible can be varied by varying the holding time of the amorphous material at the softening temperature.

When the thickness of the intermediate layer is set to 1/3 or more, which is the thickness of the photocatalyst layer, the adhesiveness can be further increased.

The following description relates to specific embodiments.

Example 27

Forming SiO on 10cm square alumina substrate by spray coating₂-Al₂O₃-Na/K₂An amorphous layer of O system, dried and calcined, and then coated with 0.01 μm TiO by spray coating₂Dissolving in water, heating at 850 deg.CCalcining for a retention time to form anatase TiO of 0.2 μm, 0.5 μm, or 1 μm₂A film. Then, in the anatase type TiO₂The film was coated with an aqueous solution of copper acetate by spray coating, and then subjected to photoreduction (light source was a 20-watt BLB lamp, distance from the light source to the sample was 10cm, irradiation time was 30 seconds) to obtain a sample. The obtained sample was subjected to EPMA cross-sectional elemental analysis (Ti, Si) to measure the film thickness, and the antibacterial property and the abrasion resistance were evaluated.

For evaluation of antibacterial activity, Escherichia coli (Escherichia coli W3110 strain) was used for the test. 0.15ml (1-50000CFU) of the bacterial suspension was dropped onto the outermost surface of the multifunctional member sterilized with 70% ethanol in advance, and the resultant was placed on a glass plate (100X 100) so as to be in close contact with the outermost surface of the substrate, thereby obtaining a sample. After 30 minutes of irradiation with a white lamp (3500 lux), the irradiated sample bacterial solution was wiped with a sterilized gauze and collected in 10ml of physiological saline to determine the bacterial survival rate as an evaluation index. The evaluation criteria were the same as those in table 1 above.

The results are summarized in Table 18. All of them are +++, with respect to antibacterial activity.

The abrasion resistance, either ◎ or ○, showed good results, especially the samples having a ratio of intermediate layer thickness to photocatalyst layer thickness of 1/3 or more were ◎ (Table 18)

TiO₂Film thickness (μm)	Intermediate layer thickness (μm)	Retention time (hours)	Intermediate layer thickness/TiO₂Film thickness	Antibacterial property	Resistance to peeling
TiO₂Film thickness (μm)	Intermediate layer thickness (μm)	Retention time (hours)	Intermediate layer thickness/TiO₂Film thickness	Antibacterial property	Resistance to peeling	1 1 1 0.5 0.5 0.2 0.2	0.42 0.33 0.30 0.17 0.13 0.08 0.05	16 2 1 2 1 2 1	0.42 0.33 0.30 0.34 0.26 0.40 0.25	+++ +++ +++ +++ +++ +++ +++	◎ ◎ ○ ◎ ○ ◎ ○
1	0		0	+++	△	1 1 1 0.5 0.5 0.2 0.2	0.42 0.33 0.30 0.17 0.13 0.08 0.05	16 2 1 2 1 2 1	0.42 0.33 0.30 0.34 0.26 0.40 0.25	+++ +++ +++ +++ +++ +++ +++	◎ ◎ ○ ◎ ○ ◎ ○

Example 28

Coating TiO with an average particle size of 0.01 μm on a 10cm square alumina substrate by spray coating₂An ammonia dispersion of the sol was calcined at 850 ℃ to form anatase TiO particles having a thickness of 1 μm₂A film. Then, in the anatase type TiO₂Coating copper acetate solution on the film by spraying method, and thenThe sample was obtained by photoreduction (light source was a 20-watt BLB lamp, distance from the light source to the sample was 10cm, and irradiation was carried out for 30 seconds). The obtained samples were evaluated for antibacterial properties and abrasion resistance.

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

As is apparent from the above description, in the multifunctional material in which the photocatalyst layer is held on the surface of the substrate by the amorphous layer, the upper layer portion of the photocatalyst layer is exposed to be in contact with air, and the photocatalyst layer has a photocatalytic function in which particles are bonded to each other, the amorphous layer and the photocatalyst layer have an intermediate layer between which the concentrations of both components are continuously changed, whereby the adhesion between the photocatalyst thin film and the substrate can be increased and the peeling resistance can be improved. Further, the intermediate layer having a thickness of 1/3 or more based on the thickness of the photocatalyst layer can further increase the adhesiveness.

The following describes the formation of the photocatalyst layer 2 by sintering. FIG. 1(a) shows a conventional TiO compound₂The state before sintering of the particles is shown in (b), and as shown in (a) of FIG. 1, the surface of the substrate 1 is coated with a TiO-containing material₂Sol of particles 3. When the film is heat-treated (sintered) to improve the film strength, cracks 2a are likely to occur as shown in fig. 1 (b).

The reason for this is considered to be that TiO before sintering causes volume shrinkage (increase in density) in addition to phase transition to rutile type₂The spacing between the grains 101 is L₀However, since the sintered material is rutile-type, the volume of the sintered material is diffused toward the opposite side to shorten the inter-particle distance to L₁(L₁＜L₀) As a result, cracks are generated.

Thus, SnO₂Condensed on the sinter-bonded TiO₂The necking part of the particle 3 is made thick to strengthen TiO₂The particles 3 are bonded to each other, resulting in an increase in film strength.

SnO was added to form the photocatalyst layer 2 as described above₂Sol on TiO₂Mixing the sol with stirring, coating on the substrate 1, and performing heat treatment (firing) in a predetermined temperature rangeA knot).

In addition, TiO₂The sol concentration is about 4-6% by weight, using NH₃The solution was adjusted to pH11, TiO₂The average 1-th order particle diameter of the particles was 0.01. mu.m (10nm), SnO₂The sol concentration is about 10% by weight, with NH₃The solution was adjusted to pH11, SnO₂The average 1-time particle diameter of the particles was 0.0035 μm. The average 1 st-order particle diameter shown here is the crystallite size (1 st-order particle) determined from the half-value width of the diffraction line of XRD (X-ray diffraction)Pellets).

Here, because of SnO₂Has a vapor pressure higher than that of TiO₂So that TiO is present before sintering₂The interval between the particles 3 is L0 as shown in fig. 17(a), but the surface vapor pressure of the surface having the positive curvature of the titanium oxide particles 3 is high, and the surface vapor pressure of the surface having the negative curvature, that is, the surface vapor pressure of the constricted portion where 2 titanium oxide particles 3 are in contact with each other is low. As a result, SnO having a higher vapor pressure than that of titanium oxide was shown in FIG. 17(b)₂Entering the neck-down portion, as shown in fig. 17(c), the resulting material condenses, and is sintered by a vaporization-condensation mechanism.

Further, when sintering is performed according to the vaporization-condensation mechanism, the sintered TiO₂Spacing L of particles₂Approximately equal to the spacing L before sintering₀And thus no cracks are generated.

As mentioned above, before and after sintering, the TiO is allowed to react₂The spacing between the particles is not substantially changed and the photoactivity (R) of the photocatalyst coating film is to be made substantially constant₃₀) At least 50%, SnO must be used as shown in FIG. 28₂To TiO 2₂The ratio (internal ratio) of (A) to (B) is 20-70% or more.

The mixing ratio indicates the weight ratio of solid components contained in each sol. The photoactivity was evaluated by the decomposition of methyl mercaptan and the removal rate (R) after 30 minutes of light irradiation₃₀) As an index. Specifically, 150 square tiles on which a photocatalyst coating film was formed were placed in an 11L glass container at a distance of 8cm from a light source (BLB fluorescent lamp, 4W), methyl mercaptan gas was injected into the container at 3 to 5ppm, and after confirming that there was no adsorption in the dark, the fluorescent lamp was turned on, and the change in concentration with time was measured by gas chromatography.

Here, R₃₀＝(X₀-X₃₀)/X₀×100％

Wherein X₀Initial concentration [ ppm]X₃₀Concentration after 30 minutes [ ppm]

Further, the film strength was evaluated by performing sliding friction using a plastic rubber and comparing the change in appearance, and the evaluation criteria ◎, ○, △ and x were the same as those described above (table 1).

FIG. 29 is a graph showing the relationship between the heat treatment temperature and the photoactivity, in TiO₂When the organic stabilizer is added to the sol, the photoactivity is reduced, but the heat treatment temperature is 300-850 ℃. This is because the heat treatment temperature is 300 ℃ or lower and the activity is hardly generated, if it exceeds the above rangeAt 850 ℃ above, TiO₂The structure of (a) changes from anatase to rutile.

As is apparent from the above description, since a sol containing titanium oxide particles and a substance having a higher vapor pressure than titanium oxide is applied to a tile or the like and baked at a predetermined temperature to form a coating film by sintering through a vaporization-condensation mechanism, the intervals between the titanium oxide particles are substantially equal before and after sintering, and cracking is less likely to occur. In addition, SnO is condensed at the constricted parts between titanium oxide particles₂And so on, the peel strength of the coating film becomes high.

In particular, SnO₂Etc. (in combination with TiO)₂Internal ratio of (d) to 20 to 70%, and can satisfy the requirements of film strength and optical activity, and can obtain sufficient optical activity by performing heat treatment at 300 ℃ or higher and 850 ℃ or lower.

However, R was measured by gas chromatography₃₀The measuring device is high in cost, and only one sample can be measured by one device, so that the efficiency is poor.

In addition, although known in TiO₂The metal such as Pt supported thereon improves the photoactivity, but in the photocatalyst thin film having such a structure, it is difficult to determine the degree of net photoactivity due to the influence of gas adsorption caused by the metal.

Further, when tiles are used as wall surfaces, the activity of the photocatalyst thin film formed on the surface cannot be measured by a gas chromatograph after the tile is once applied.

Further, as a method for evaluating the photoactivity without using a gas chromatograph, a method of detecting the survival rate after light irradiation which kills bacteria by the action of a photocatalyst may be considered, but the operation is more troublesome than that of a gas chromatograph, and the bacteria are killed by the antibacterial activity of the metal itself in a metal-supported photocatalyst thin film, so that it is difficult to judge the net photoactivity. Therefore, the following method for measuring the activity of the photocatalyst thin film can be applied.

Method 1 formation of TiO on a substrate surface₂An aqueous solution of potassium halide such as potassium iodide or potassium chloride is dropped onto the surface of the main photocatalyst thin film, and then the dropped aqueous solution of potassium halide is irradiated with ultraviolet light for a predetermined time. The activity of the photocatalyst thin film was judged from the difference between the pH of the aqueous potassium halide solution before irradiation and the pH after irradiation.

Method 2 formation of TiO on a substrate surface₂A mixed solution in which a pH indicator is added to an aqueous solution of potassium halide such as potassium iodide or potassium chloride is dropped on the surface of the main photocatalyst thin film, and then the dropped mixed solution is irradiated with ultraviolet light for a predetermined time, whereby the color of the mixed solution changes, and the activity of the photocatalyst thin film can be determined.

Method 3 formation of TiO on a substrate surface₂The activity measuring film is adhered to the surface of the main photocatalyst thin film, and the activity measuring film is irradiated with ultraviolet rays for a predetermined time in this state, whereby the color of the activity measuring film changes, and the activity of the photocatalyst thin film can be determined.

FIG. 30 illustrates the 1 st and 2 nd activity measuring methods, in which TiO is formed on the surface of the substrate 1₂Such a method for measuring the activity of a photocatalyst thin film can be applied to the photocatalyst layer 2 as a main body.

Method 1 formation of TiO on a substrate surface₂An aqueous solution of potassium halide such as potassium iodide or potassium chloride is dropped onto the surface of the photocatalyst thin film as a main body, and then the dropped aqueous solution of potassium halide is irradiated with lightThe photocatalyst thin film was irradiated with ultraviolet light for a predetermined period of time, and the activity of the photocatalyst thin film was determined from the difference between the pH of the aqueous potassium halide solution before irradiation and the pH after irradiation.

Method 2, formation of TiO on the surface of a substrate₂The amount of activity of the photocatalyst thin film can be determined by dropping a mixed solution prepared by adding a pH indicator to an aqueous solution of potassium halide such as potassium iodide or potassium chloride on the surface of the photocatalyst thin film as a main component, and then irradiating the dropped mixed solution with ultraviolet light for a predetermined time.

FIG. 30 illustrates the activity measuring methods of the 1 st and 2 nd types, in which TiO is formed on the surface of the substrate 1₂A main photocatalyst layer 2, for detecting whether or not the photocatalyst layer 2 is presentWhen the photocatalyst layer 2 has optical activity, an aqueous solution 30 of potassium halide such as potassium iodide or potassium chloride is dropped onto the surface of the photocatalyst layer 2, and then the dropped aqueous solution 30 of potassium halide is irradiated with ultraviolet light for a predetermined time by an ultraviolet lamp 40, and the magnitude of the activity of the photocatalyst layer 2 is determined from the difference between the pH of the aqueous solution of potassium halide before irradiation and the pH after irradiation.

FIG. 33 shows the relationship between the UV irradiation time and the amount of pH change, the concentration of the potassium halide aqueous solution 30 was 0.1mol/L, a 20W BLB fluorescent lamp was used as a UV lamp, the distance between the photocatalyst layer 2 and the UV lamp 40 was 20cm, and the irradiation time was 60 minutes.

From this figure, it can be seen that the photocatalyst layer 2 had a high pH of the potassium halide aqueous solution 30 when the ultraviolet irradiation time reached 30 minutes, regardless of the anatase type, the metal-supported type, or the rutile type.

The reason why the pH of the potassium halide aqueous solution 30 is increased by the ultraviolet irradiation is that the following oxidation reaction and reduction reaction are simultaneously carried out, and OH is generated by the reduction reaction^-(hydroxide ion).

And (3) oxidation reaction:

reduction reaction:

therefore, if the pH of the potassium halide aqueous solution 30 becomes high due to the irradiation of ultraviolet rays, the photocatalyst layer 2 can be said to have photoactivity.

FIG. 34 shows R₃₀Change in pH. In the figure, R₃₀Is the proportion (%) of gas (methyl mercaptan, etc.) which decreases 30 minutes after the ultraviolet irradiation, and from this figure, it is known that R is₃₀And has a direct proportional correlation with the pH variation. That is, the change in pH becomes an indicator of the presence or absence of photoactivity.

In the above-mentioned method 1, the change in pH is performed by a pH meter or a pH measuring sheet, but in the method 2, a mixed liquid obtained by adding a pH indicator to a potassium halide aqueous solution 30 is dropped on the surface of the photocatalyst layer 2, and then the dropped mixed liquid is irradiated with ultraviolet light for a predetermined time, whereby the color of the mixed liquid changes, and the activity of the photocatalyst layer 2 can be determined.

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

In the

methods

1 and 2, the potassium halide aqueous solution 30 is dropped on the surface of the photocatalyst layer 2 or a mixed solution of the potassium halide aqueous solution 30 and a pH indicator is added thereto, and the liquid dropped on each substrate spreads in various colors, and a constant liquid thickness cannot be secured, and the reaction area varies from substrate to substrate.

A method for eliminating this is a method shown in fig. 31, in which after dropping the potassium halide aqueous solution 30 or the like on the surface of the photocatalyst layer 2, the potassium halide aqueous solution 30 is pressed with a transparent plate 60 such as a glass plate to form a certain thickness and prevent drying.

Further, since the liquid such as the aqueous potassium halide solution 30 is conditioned on the condition that the surface of the substrate 1 is horizontal, it is difficult to determine the activity of the photocatalyst film formed on a vertical surface such as an established wall surface or a ceiling.

A method for eliminating this is a method shown in fig. 32, in which an activity measuring film 70 is adhered to the surface of the photocatalyst layer 2 formed on the surface of the substrate 1, and the activity measuring film 70 is irradiated with ultraviolet rays in this state, and the magnitude of the activity of the photocatalyst layer 2 can be judged due to the color change of the activity measuring film 70.

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

Next, the porosity of the photocatalyst layer 2 was examined. The porosity is referred to as open porosity, and is preferably 10% to 40%, more preferably 10% to 30%.

In this case, the crystal particle diameter of the photocatalyst particles may be 0.1 μm or less, preferably 0.04 μm or less. Since the smaller the crystal grain size, the larger the reaction effective area per unit volume, the film thickness of the photocatalyst layer may be about 0.1 μm. Further, when the layer strength is improved by solid-phase sintering the photocatalyst particles with each other to form a neck portion, the crystal grain size is increased to 0.1 μm or more, and the reaction effective area per unit volume is decreased, so that the film thickness is set to 0.5 μm or more, preferably 0.6 or more.

Further, it is possible to add particles having a crystal grain size of 0.01 μm or less, preferably 0.008 μm or less to the photocatalyst particles constituting the photocatalyst layer formed on the surface of the substrate, and by adding such particles, the gaps between the photocatalyst particles can be filled, and the particle filling ratio and surface smoothness can be improved, whereby the film strength against shear stress can be improved, and contamination can be made less likely to adhere due to the improvement of the surface smoothness, and in this case, the porosity is reduced, but the pore size to be filled here is a size in which the particles having a crystal grain size of 0.01 μm or less, preferably 0.008 μm or less enter, and is larger than the size of gas (number Å), and therefore, the odor resistance is not affected.

Here, the crystal grain size is 0.01 μm or less, preferably 0.008 μm or lessThe kind of the particles (A) may be basically any, but there is a risk that the photocatalyst particles are partly covered with the particles except for filling the gaps between the photocatalyst particles, so that the photocatalytic activity is not impaired by TiO₂、SnO₂、ZnO、SrTiO₃、Fe₂O₃、Bi₂O₃、WO₃And the like, or metals such as Ag, Cu, and the like are preferable. The method of adding the particles having a crystal grain size of 0.01 μm or less, preferably 0.008 μm or less may be basically any method. For example, such ultrafine particles as produced by hydrothermal treatment or the like are dispersed in an appropriate dispersion to form a sol, the sol is applied to the photocatalyst layer by a spray coating method, and heat treatment is performed at a low temperature at which particle growth does not occur, thereby evaporating the organic dispersant. Further, the photocatalyst layer may be coated with a metal alkoxide or an organic metal salt, heat-treated, and the diluent, the organic component, or the like may be evaporated.

In addition, metal particles having a pore diameter smaller than that of the photocatalyst layer formed on the surface of the substrate may be fixed. By fixing the metal particles, the photocatalytic activity is improved and the deodorizing property is improved more than when a photocatalyst layer is used alone, by utilizing the electron trapping effect.

Here, the kind of the metal particles may be any substance capable of trapping electrons. Examples thereof include Cu, Ag and Pt.

The average particle diameter of the metal particles must be smaller than the average pore diameter of the surface of the photocatalyst layer. Further, if the average pore diameter of the surface of the photocatalyst layer is observed with an electron microscope using a sample having a porosity of 10% or more and 40% or less, the diameter is approximately equal to that of the photocatalyst particles, and therefore, it is required to be smaller than the photocatalyst particle diameter. It may be desirably smaller than the photocatalyst particle size of the starting material. The starting material for the photocatalyst layer is generally 0.05 μm or less, and therefore may be 0.05 μm or less.

Specific examples of the porosity are given below.

Example 28

Spraying on a 15cm square ceramic tile substrateCoating method, coating TiO with crystal grain size of 0.01 μm by changing coating amount₂An ammonolysis type suspension of the sol is calcined at 700 ℃ to 900 ℃ to form a photocatalyst layer, and the obtained sample is evaluated for anatase type TiO₂The crystal grain size of the particles, the open porosity of the surface of the layer, odor resistance, wear resistance and peeling resistance.

Evaluation of odor resistance by measuring R₃₀(L) evaluation was carried out. So-called R₃₀The removal rate after the light irradiation was specifically obtained by placing the surface on which the photocatalyst thin film of the sample was formed in a glass container of 11 liters at a distance of 8cm from the light source (BLB fluorescent lamp, 4W), injecting the photocatalyst thin film into the container so that the initial concentration of the methyl mercaptan gas was 3ppm, and measuring the change in concentration after the irradiation for 30 minutes.

The abrasion resistance was evaluated by comparing changes in appearance by using sliding friction of a plastic rubber, and the evaluation index was the same as described above and shown below.

◎ not changing for 40 times of reciprocating

○ sliding on the surface of the substrate for 10 to 40 times or less to form scratches thereon, and a photocatalyst layer (TiO)₂Film) peeling

△ sliding on the surface of the substrate for 5 to 10 times or more to form scratches thereon, and a photocatalyst layer (TiO)₂Film) peeling

X: sliding less than 5 times has scratches, photocatalyst layer (TiO)₂Film) peelingAnd (5) separating.

The peel resistance test is a test under severer conditions than the abrasion resistance test, and a sand rubber (LION typewriereraser 502) having a larger shearing force is used instead of the plastic rubber. The specific evaluation method was carried out by rubbing the sample surface with a sand eraser 20 times with a uniform force and visually observing the state of containing a flaw as compared with a standard sample. The evaluation criteria are shown below.

◎ no change at all

○ slight change in the color of the sample when light was added or subtracted

△ confirmation of slight variations

X: can confirm the change at a glance

The results are shown in FIGS. 35-37.

FIG. 35 shows the relationship between the porosity and the odor resistance and the abrasion resistance when the thickness of the photocatalyst film is 0.8 μm, and the odor resistance increases with the increase in the porosity, and exceeds 50% at 10% and reaches 80% or more at 30%, and conversely, ◎ is the abrasion resistance to 30%, ○ is the amount at 40%, and △ or X is the amount exceeding this, and from the fact that the porosity of the photocatalyst film must be 10% or more and 40% or less, preferably 10% or more and 30% or less, in order to produce a member having both odor resistance and abrasion resistance.

FIG. 36 shows the relationship between odor resistance and film thickness when the crystal grain size of photocatalyst particles constituting a photocatalyst thin film having a porosity of 20 to 30% was changed. R is observed when the crystal grain size is 0.1. mu.m₃₀(L) the relation with the film thickness, if thinner, the deodorization performance is reduced. However, no relation with the film thickness was observed at 0.04 μm or less, and even the film thickness was 0.1 μm, good odor-preventing property was exhibited. From the above facts, it is understood that when the crystal grain size of the photocatalyst particles is 0.1 μm or less, preferably 0.04 μm or less, the photocatalyst thin film can be made thin to a film thickness of about 0.1 μm, and excellent odor resistance can be secured.

FIG. 37 shows the relationship between the odor resistance and peeling resistance and the film thickness when the crystal grain size and the bonding state of the photocatalyst particles constituting the photocatalyst thin film having a porosity of 20 to 30% were changedWhen the required value of mechanical strength is increased to the peeling resistance test level, the sample without the neck part is △ or x, and when the photocatalyst particles are grown to 0.1 μm, the photocatalyst particles are not sufficiently grown to 0.04 μm and need to be grown to 0.1 μm in order to form a mechanically sufficient neck bond by solid-phase sintering between the photocatalyst particles, however, when the photocatalyst particles are grown to 0.1 μm, the deodorization property is already related to the film thickness, and the deodorization property is increased as the film thickness is thicker, specifically, when the film thickness is 0.5 μm, R is increased₃₀(L) is more than 50%, and is 80% or more at 0.6 μm. From the above results, it is found that the film strength can be sufficiently improved by solid-phase sintering of photocatalyst particles to form necking parts between the particles and growing the particles to a crystal grain size of 0.1 μm or more. In this case, the crystal grain size is increased by increasing the crystal grain size0.1 μm or more, and the reaction effective area per unit volume is reduced, so that the film thickness must be 0.5 μm or more, preferably 0.6 μm or more.

Example 29

Coating TiO with crystal grain size of 0.01 μm on a tile substrate of 15cm square by spray coating₂The ammonolysis type suspension of the sol is calcined at 750 ℃ to form the photocatalyst film. TiO at this stage₂The porosity of the film was 45%, TiO₂The crystal grain size of the particles was 0.02. mu.m. Respectively coating SnO with different crystal grain sizes on the surface of the substrate by a spraying method₂The sol was dried at 110 ℃ to obtain a sample. The obtained samples were evaluated for odor resistance and abrasion resistance.

The results are shown in fig. 38. With respect to odor resistance, SnO₂The crystal grain size of the sol was changed from 0.0035 μm to 0.01. mu.m, and good results were obtained. On the contrary, the effect of the abrasion resistance at the addition of 30% by weight or more depends on SnO₂That is, in the case of adding particles of 0.008 μm or less, the addition effect was improved to ◎ or ○, but the addition effect was not observed at 0.01 μm.

From the above results, it is understood that the abrasion resistance is improved by adding particles having a crystal grain size of 0.01 μm or less, preferably 0.008 μm or less, to the photocatalyst particles.

Example 30

Coating TiO with crystal grain size of 0.01 μm on a tile substrate of 15cm square by spraying method with variable coating amount₂The sol-gel-ammonolyzed suspension was calcined at 850 ℃ to form a photocatalyst thin film having a thickness of 0.2 μm. Then, an aqueous solution of copper acetate was applied to the photocatalyst thin film by a coating method, and then photoreduction was carried out (light source 20W BLB lamp, distance from the light source to the sample was 10cm, irradiation time was 10 seconds), to obtain a sample. The amount of copper supported at this time was 2. mu.g/cm²The particle size is several nm to 10 nm. Further, the crystal particle diameter of the photocatalyst particles was 0.1. mu.m. The obtained samples were evaluated for odor resistance and abrasion resistance.

As a result, R₃₀Since (L) is 80% and the abrasion resistance is ◎, the carrier is supported as compared with FIG. 36Copper, so R₃₀(L) rose dramatically from 18% to 89%.

As is apparent from the above description, a photocatalyst film having a porosity of 10% or more and 40% or less, preferably 10% or more and 30% or less is formed on the surface of the base material, whereby a member having both odor resistance and abrasion resistance can be provided.

Next, an example in which particles smaller than the gap are filled in the gap formed on the photocatalyst layer will be described. The gap in the present embodiment refers to both the gap between the separated particles and the recess of the constriction.

Further, although the photocatalyst layer is excellent in film strength and is less likely to be contaminated when it is dense, the temperature at which the photocatalyst layer is formed is generally high, and the material of the base material is limited, so that the porosity of the photocatalyst layer before the addition of interstitial particles may be 10% or more according to the desire to fill the interstitial particles in the subsequent step. Further, since the film having a porosity of 10% or more has excellent odor resistance, a multifunctional material having both excellent odor resistance and excellent odor resistance can be provided by adjusting the amount of the filler.

The particles smaller in the interstices than the filled interstices preferably consist of a starting material of inorganic crystalline material, more preferably of a material derived from TiO with photocatalytic activity₂、SnO₂、ZnO、SrTiO₃、Fe₂O₃、Bi₂O₃、WO₃And the like.

The size of the particles smaller than the gap may be substantially smaller than the average of the generated pore diameters. The reduction of the gaps and the reduction of the particles adhering to the surfaces of the particles having a photocatalytic function improve the surface smoothness and the reduction of surface defects, and specifically, the particles may be small particles of 0.01 μm or less, preferably 0.008 μm or less, in order to prevent the adhesion of the contamination and improve the film strength. However, in TiO₂The film is anatase type, and when it is fixed on the substrate by heat treatment at 850 ℃ or lower, the film is observed with an electron microscope from the average pore diameter and TiO₂Particle diameter is approximately equal to that of TiO₂The particle size is small. Has lightCatalytically active TiO₂The starting material for the film is usually 0.05 μm or less, and therefore may be 0.05 μm or less.

Here, the surface porosity of the layer having a photocatalytic function, which is formed by filling the gaps with particles, is 20% or less, and contamination is less likely to adhere. More preferably, the maximum width of the open pores is 0.04 μm or less.

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

In addition, if a layer having a photocatalytic function before the particles are filled in the gaps is used, the porosity of the layer is reduced to 10% or less, but the pore diameter embedded therein is a size into which the particles having a crystal grain size of 0.01 μm or less are inserted, and is larger than the gas size (number Å), so that the odor resistance is not affected, and the layer can be compared with a previously prepared TiO having a porosity of 10% or more₂The membrane retains equivalent anti-odor properties.

In addition, the layer having the photocatalytic function formed is mainly composed of crystalline photocatalyst particles, so that the scale is not adhered in a glass adhesion type strong adhesion form, and the scale is relatively easily wiped off even if adhered. In addition, when water is recycled, algae is not easily generated.

The crystalline photocatalyst particles are those having a maximum peak of crystallization (for example, in TiO) when the photocatalyst particles peeled off from the member are subjected to powder X-ray diffraction under conditions of 50KV and 300mA₂In the particles, anatase type 2 θ is 25.3 ° and rutile type 2 θ is 27.4 °)The detected degree of crystallization was changed to photocatalyst particles.

As a method for filling the gap with the particles, an alkoxide, an organic metal salt, a sulfate, or the like is used, and the filling is performed by coating, drying, and heat treatment. For example, the process of using a metal alkoxide is to coat a solution of a metal alkoxide mixed with a suitable diluent and hydrochloric acid on the outermost surface of a photocatalyst layer, and then to perform a drying heat treatment. The diluent is preferably alcohols such as ethanol, propanol, and methanol, but is not limited thereto. It may be as free as possible of water. If water is contained, hydrolysis of the metal alkoxide is promoted explosively, which causes cracking. The hydrochloric acid is added to prevent cracking during drying and heat treatment. The metal alkoxide coating method is generally performed by a shower coating method. But is not limited thereto. The curtain coating is preferably carried out in dry air. When the coating is applied in normal air (atmosphere), hydrolysis is promoted by moisture in the air, and it becomes difficult to control the film thickness. The coating may be applied 1 time or several times. This is determined by the filling property of the photocatalyst layer before coating. After that, the photocatalyst layer was left in dry air for several minutes to form a film in which the gaps of the photocatalyst layer were filled with particles.

Here, if the filler particles are made of the same material as the layer before the filler particles are applied, the thermal expansion coefficient is also the same, and a film having excellent mechanical strength can be formed, which is desirable.

As a specific example, an example using titanium alkoxide will be described. In the process of coating titanium alkoxide on the surface of the photocatalyst layer again and carrying out drying heat treatment, the coating amount of titanium alkoxide per time is converted into TiO₂Is 10. mu.g/cm²Above 100 mu g/cm²The following. If the amount is too small, the number of coating times must be increased, resulting in low efficiency, whereas if the amount is too large, the film thickness per coating is too thick, resulting in cracks during drying and heat treatment.

In the drying heat treatment process, the heat treatment temperature is above 400 ℃ and below 800 ℃, and at below 400 ℃, the amorphous TiO is₂Not crystallized into anatase type TiO₂And sharp particle growth occurs at 800 ℃, so that the photoactivity is reduced.

The amount of hydrochloric acid is 1 to 10 wt% based on the amount of the titanium alkoxide in the coating solution. At less than 1% by weight, the effect of preventing cracks is insufficient, and if it exceeds 10% by weight, hydrochloric acid is usually 36% aqueous solution, and a large amount of water is contained, so that hydrolysis is accelerated excessively, and cracks are formed. When the amount of hydrochloric acid is large, the amount of the diluent may be large. Since the diluent inhibits hydrolysis. The proportion of the hydrochloric acid (except water) to the diluent can be about 1: 100-1: 1000.

Further, a layer having a photocatalytic function is formed, and at least one metal selected from the group consisting of Cu, Ag, Zn, Fe, Co, Ni, Pd, and Pt may be further fixed to the layer in which the gaps formed on the surface of the layer are filled with particles smaller than the gaps. With such a structure, the metal occupies a site having high adsorptivity in the layer having the photocatalytic function in advance, and alkali metal, calcium, and the like in the dust component adhere to the site without losing the photocatalytic activity. Therefore, the antibacterial action by the photocatalyst is hardly impaired, and contamination by adhesion of bacteria can be prevented. Further, when Ag, Cu, or Zn is used as the metal, the metal itself has antibacterial properties, and therefore, the adhesion of fungi can be more effectively prevented. The electron trapping effect of these metals is also reused to improve the photoactivity of the photocatalyst layer.

The size of the metal to be fixed is large enough to occupy a site of the photocatalyst layer having a high adsorbability in advance, and can be small enough to maintain high activity. From this viewpoint, it is preferably in the range of several nm to 10 nm.

Here, as a method for fixing the metal, photo-reduction, heat treatment, sputtering, chemical vapor deposition, or the like can be used, but photo-reduction is preferable in that a large-scale facility is not required, a relatively simple method is not required, and strong fixing is possible. The photo-reduction process comprises applying an aqueous solution containing at least one metal ion selected from Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt, and irradiating with ultraviolet light. Examples of the aqueous solution containing at least one metal ion of Ag, Cu, Zn, Fe, Co, Ni, Pd, and Pt include copper acetate, silver nitrate, copper carbonate, copper sulfate, cuprous chloride, copper oxide, chloroplatinate, palladium chloride, nickel chloride, zinc nitrate, cobalt chloride, ferrous chloride, and ferric chloride. The method of coating these metal salts can be basically any of the above-mentioned methods, but the spray coating method or the dip coating method is simple. In comparison, the spray coating method is more preferable in that the amount of the solution used is small, the coating can be performed uniformly, the film thickness can be easily controlled, and the coating does not adhere to the back surface as required. When the light source containing ultraviolet light is irradiated, any light source may be used as long as it can irradiate the light source 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. The method of irradiating ultraviolet-containing light desirably arranges the sample so that the light is irradiated perpendicularly onto the irradiation surface because the irradiation rate is optimized. The irradiation time is preferably about 10 seconds to 10 minutes. If the irradiation time is too short, the metal is not sufficiently adhered to the site of the photocatalyst layer having high adsorbability, and the alkali metal, calcium, and the like in the dust component are adhered, which causes the loss of the photocatalytic activity, and if the irradiation time is too long, the metal is excessively adhered, and it is difficult for the light to sufficiently reach the photocatalyst layer, thereby lowering the photocatalytic activity. The distance of the sample from the light source is preferably 1cm to 30 cm. If the distance is too short, the light cannot be irradiated over the entire sample surface with substantially uniform illuminance, and the metal adhesion deviation is likely to occur.

Specific examples of filling the gaps formed in the photocatalyst layer with particles smaller than the gaps will be described below.

Example 31

Coating TiO with crystal grain size of 0.01 μm on a tile substrate of 15cm square by spray coating₂Ammonolysis type suspension of sol, calcining at 750 deg.C to form anatase TiO₂A film. TiO of this stage₂The porosity of the film was 45%, TiO₂The crystal grain size of the particles was 0.02. mu.m. Then coating SnO with different crystal grain sizes on the surface by a spraying method₂The sol was dried at 110 ℃ to obtain a sample. The obtained sample was evaluated for odor resistance, abrasion resistance, and difficulty of adhesion of stain.

Odor resistance was measured by measuring R₃₀(L) evaluation was carried out.

The abrasion resistance was evaluated by performing sliding friction using a plastic rubber and comparing the change in appearance. The evaluation index is as follows.

◎ No change for 40 reciprocations

○ abrasion and TiO sliding for more than 10 times and less than 40 times₂Layer stripping

△ abrasion and TiO sliding for more than 5 times and less than 10 times₂Layer stripping

X: sliding less than 5 times has scratches, TiO₂And (6) stripping the layers.

The difficulty of adhesion of stains was evaluated by drawing a black thick universal line on the surface of the substrate, and wiping off the line with ethanol after drying. The evaluation index is shown.

◎ complete disappearance of traces.

○ slight residual marks.

△ residual lime green trace.

X: a black mark remained.

The results are shown in FIGS. 39-46.

FIG. 39 shows a graph against SnO₂The addition amount and the difficulty of adhesion of the pollution. SnO in this figure₂Added in an amount corresponding to the amount of TiO₂And SnO₂Amount by weight and SnO₂The weight ratio is expressed. Adding more than 30% of SnO₂In this case, the adhesion of the stain hardly rises at a rapid rate. The reason for this is explained by the following three points. The first is due to the addition of more than 30% SnO₂Therefore, the porosity was reduced to 20% or less (FIG. 40). Secondly, due to the addition of SnO₂The pores having a large pore diameter are reduced. FIG. 41 shows a graph relating to SnO₂The maximum width of open pores, SnO₂When the amount of (B) is 30% or more, the particle diameter becomes quite small, i.e., 0.04 μm. Thirdly, due to the addition of SnO₂The surface finish is improved and also has an effect.

FIG. 42 is a graph showing a relationship with SnO₂Odor resistance and abrasion resistance in the added amount.

Regarding the deodorizing property, namely SnO₂The crystal grain size of the sol hardly changed from 0.0035 μm to 0.01. mu.m, showing good results. Further, SnO₂When the amount of (B) is 50% or less, R₃₀Good results of 80% or more are shown. SnO comparison of FIG. 39₂SnO was found to be dependent on the amount added and the porosity₂The addition amount of (B) is 40% to 50%The reason for this tendency is considered to be that although the porosity in this case is reduced to 10% or less, pores of about 0.02 μm remain as compared with FIG. 41, and the crystal grain size of the particles filling the gaps is 0.0035 μm which is larger than the size of the gas (number Å), so that the phenomenon that the gas passage is blocked does not occur under the present condition that the particles do not grow large.

With respect to abrasion resistance, in SnO₂SnO for the effect when the amount of addition is 30% or more₂The crystal particle size of the sol varied, that is, when particles of 0.008 μm or less were added, the particle size was improved to ◎ or ○, but no effect of addition was observed at 0.01 μm.

From this experiment, it can be seen that:

(1) formation of TiO on a substrate₂In the film, particles (SnO) smaller than the gaps are added to the gaps formed on the surface of the film₂Sol), the contamination is difficult to adhere.

(2)SnO₂Is added in an amount based on the TiO₂And SnO₂When the total weight is 30% or more by weight, the stain is not easily adhered and the abrasion resistance is improved.

(3)SnO₂Is added in an amount based on the TiO₂And SnO₂If the total weight is 50% by weight or less, the deodorizing property can be maintained as good.

(4) When the porosity is 20% or less and the maximum width of the open pores is 0.04 μm or less, the contamination is less likely to adhere.

Example 32

Anatase type TiO is formed on the side part of the urinal operator which is not exposed to light₂Two weeks of in-situ testing was conducted with no formation of normal anatase TiO₂As a result of comparison of the materials of the membranes, yellow stains derived from bacteria, kidney stones, bladder stones, and the like were attached to both of the membranes. However, it is compatible with the ordinary toiletThe dirt on the grate is not fallen off, and anatase type TiO is formed at the side part₂When the film material was wiped, the yellow color of dirt was almost remarkably disappeared.

The result of the absence of light irradiation at the side of the grate was interpreted as the absence of anatase TiO₂The photocatalytic effect of the film is not limited to the formation of crystalline anatase TiO on the surface, which is difficult to adhere firmly with dirt₂And (3) a membrane.

Example 33

Coating SiO on the surface of a ceramic tile with the square shape of 15cm₂-Al₂O₃-Na/K₂O glass frit, followed by coating TiO having a crystal grain size of 0.01 μm on the surface thereof by spray coating₂The sol-ammonolyzed suspension is calcined at 750 deg.C for 2 hr according to TiO₂The film thickness of the thin film was set to three kinds of 0.2. mu.m, 0.4. mu.m, and 0.8. mu.m. TiO of this stage₂The porosity of the film was 45%, TiO₂The crystal grain size of the particles was 0.02. mu.m. On the cooled sample, a mixed solution of tetraethoxytitanium, 36% hydrochloric acid and ethanol at a weight ratio of 10: 1: 400 was further applied by a curtain coating method using dry air as a carrier gas, followed by drying. Coating weight is according to TiO₂Calculated as 40-50 mug/cm². After which calcination was carried out at 500 ℃ for 10 minutes. The titanium alkoxide coating process is carried out 1 to 5 times. The obtained samples were evaluated for odor resistance, antibacterial properties, abrasion resistance, and adhesion difficulty of stains.

For the antibacterial property, the test was carried out using Escherichia coli W3110 strain. 0.15ml (1-50000CFU) of the bacterial suspension was dropped onto the outermost surface of the multifunctional material sterilized with 70% ethanol in advance, and the resultant was placed on a glass plate (100X 100) and adhered to the outermost surface of the substrate to prepare a sample. After 30 minutes of irradiation with a white lamp (3500 lux), the bacterial solution of the irradiated sample was wiped with a sterilized gauze and collected in physiological saline to determine the bacterial survival rate, which is the evaluation index +++, ++, -, is the same as described above.

Odor resistance R under any of the conditions mentioned above₃₀(L) is more than 80%, and the antibacterial property is +++.

Relating to the adhesion of dirtDifficulty (FIG. 44) and abrasion resistance (FIG. 45) depending on the number of times the titanium alkoxide was applied and the TiO₂And (5) film thickness. When the number of times of coating the titanium alkoxide is large, the adhesion difficulty of the stain and the abrasion resistance are improved. In addition, TiO₂Titanium alkoxide coating which can be reduced as the film thickness is reducedThe times improve the attachment difficulty and the wear resistance of the pollution. One reason for this is considered to be TiO formed by coating titanium alkoxide₂The porosity of the layer surface decreases. In FIG. 46, TiO is shown₂Porosity of layer surface, coating frequency of alkoxy titanium and TiO₂The relationship of film thickness. The greater the number of coating times of the titanium alkoxide, the more TiO₂The porosity of the surface of the layer is reduced, and TiO is added₂The thinner the film thickness, the same number of coating times of titanium alkoxide, TiO₂The more the porosity of the surface of the layer decreases, this relationship is related to the number of times the titanium alkoxide is applied and to the TiO content₂Particularly, regarding the difficulty of adhesion of contamination, ◎ was obtained for the porosity of 30% or less, as in the case of example 31.

Example 34

Coating SiO on the surface of a ceramic tile with the square shape of 15cm₂-Al₂O₃-Na/K₂O glass frit, on the surface of which TiO with a crystal grain size of 0.01 μm is coated by spraying₂Ammonolysis type suspension of sol, calcining at 750 deg.C for 2 hr, TiO in this stage₂The film thickness of the thin film was 0.4. mu.m, the porosity was 45%, and TiO₂The crystal grain size of the particles was 0.02. mu.m. On the cooled sample, a mixture of tetraethoxytitanium and 36% hydrochloric acid and ethanol at a weight ratio of 10: 1: 400 was further applied by a curtain coating method using dry air as a carrier gas, followed by drying. Coating amount according to TiO₂The meter is 40-50 mu g/cm². Then calcined at 500 ℃ for 10 minutes. The titanium alkoxide coating process was repeated three times. Thereafter, the sample was coated with 1% by weight of an aqueous silver nitrate solution and subjected to photoreduction (20W BLB lamp as a light source, a distance from the light source to the sample was 10cm, and an irradiation time was 30 seconds) to obtain a sample. Here, the amount of silver supported on the surface of the sample was 0.7. mu.g/cm²The particle size of silver is about 40nm on average. Measuring the obtained sampleAntibacterial property and antibacterial property after long-term use.

The antibacterial properties after long-term use were tested as follows. First, the surface of the obtained sample is washed well with ethanol or the like, and dried at 50 ℃. The bathtub water collected in the public bathing place was then poured into a sterilized beaker, and the sample was immersed therein and left for one month. Then, the sample is taken out, washed with ethanol or the like, and the outermost surface of the multifunctional material is sterilized with 70% ethanol. Next, 0.15ml (1-50000CFU) of a bacterial solution of Escherichia coli (Escherichia coli W3110 strain) was dropped on the outermost surface of the above sample, and the resultant was placed on a glass plate (100X 100) and adhered to the outermost surface of the substrate to obtain a sample.

After 30 minutes of irradiation with a white lamp (3500 lux), the bacterial solution of the irradiated sample was wiped with a sterilized gauze and collected in 10ml of physiological saline to determine the survival rate of bacteria as an evaluation index. The evaluation index was the same as in the antibacterial test of example 3.

The test specimen used in example 33 was also subjected for comparison.

As a result, the samples prepared in this example were all + + + + + + +, with respect to the initial antibacterial activity, but the antibacterial activity after 1 month was different between them. That is, the antibacterial activity of the sample prepared in example 33 was deteriorated to + and the sample prepared in this example showed a value of +++ which was not changed from the initial stage. This can be interpreted as silver occupying the TiO₂Since the surface of the layer has a high adsorbability, dust and the like are prevented from adhering to the high adsorbability portion during use.

As is apparent from the above description, since the layer having the photocatalytic function is formed on the surface of the substrate and the gaps formed on the surface of the layer are filled with particles smaller than the gaps, the number and size of the gaps present on the surface are smaller than those of the conventional photocatalytic thin film, and the surface smoothness is excellent, so that the film strength is improved while the deodorizing property is maintained, and the adhesion of polymers, dust, fungi and the like constituting the fouling components is prevented.

The following describes the use of a raw material having a low melting point, such as soda-lime glass, as a base material. That is, when a photocatalyst thin film is formed on the surface of a low-melting-point substrate, the substrate starts to soften at the catalyst thin film forming temperature, and the formed photocatalyst thin film is buried in the substrate, so that light does not reach the photocatalyst layer, which may cause a problem that the photocatalytic function cannot be exhibited.

Therefore, in such a case, the SiO 2 is used₂A layer having a high melting point of the base material such as a layer, and the photocatalyst particles are fixed to the base material. Specific examples are described below.

Example 35

Before the coating of titanium oxide on the soda-lime glass, the surface of the soda-lime glass is coated with silica.

Silica coating was performed on a 10cm square soda lime glass using the following method. First, tetraethoxysilane, 36% hydrochloric acid, pure water and ethanol were mixed in a weight ratio of 6: 2: 6: 86. At this time, the reaction solution was heated and left for about 1 hour. It is coated on soda-lime glass with air-flow coating.

Next, a coating solution was prepared. Tetraethoxytitanium and ethanol were mixed in a ratio of 1: 9 (by weight) to prepare a solution, and then 10% by weight of 36% hydrochloric acid was added to tetraethoxytitanium to prepare a coating solution. The amount of 36% hydrochloric acid added may be 1% by weight or more and 30% by weight or less, preferably 5% by weight or more and 20% by weight or less, based on the amount of tetraethoxytitanium. By adding a suitable amount of hydrochloric acid, cracks can be prevented from occurring in the subsequent drying and baking processes. That is, the amount of hydrochloric acid is too small to sufficiently achieve the effect of preventing cracks, and the amount of hydrochloric acid is too large to accelerate hydrolysis of tetraethoxytitanium due to an increase in the amount of water contained in the hydrochloric acid reagent, thereby making it difficult to form a uniform coating film.

Next, the solution was coated on the surface of the soda-lime glass substrate by a curtain coating method in dry air. Here, dry air does not mean air containing no moisture at all, and means air containing less moisture than normal air. In this case, if the coating is performed in the normal air without drying treatment, the hydrolysis of tetraethoxytitanium is accelerated by the moisture in the air, and the amount of the coating film formed at one time becomes too large, and the coating film is dried laterCracks are easy to generate in the drying and roasting processes. In addition, since hydrolysis is accelerated, it is difficult to control the amount of coating film. In order to prevent cracks, it is desirable that the primary supporting amount of titanium oxide is 100. mu.g/cm²The following. The primary supporting amount of this titanium oxide was 45. mu.g/cm²。

Then, the titanium oxide film is formed by drying treatment in dry air for 1 to 10 minutes. The titanium oxide was obtained by the following procedure. Here, the starting material is titanium tetraethoxide which is one of titanium alkoxides (the same effect is produced in principle even if other titanium alkoxides are used). Takes tetraethoxy titanium as main material, and carries out hydrolysis reaction with water in dry air during curtain coating to generate titanium hydroxide. Further, dehydration condensation reaction occurs during drying, and amorphous titanium oxide is formed on the base material. The titanium oxide particles produced at this time were about 3 to 150nm and had high purity. Therefore, this titanium oxide is characterized by being sintered at a low temperature as compared with titanium oxides obtained by other production methods.

The composite member obtained by the method is roasted at the temperature of 300-500 ℃ to obtain the multifunctional material. The process from tetraethoxytitanium to firing is repeated, if necessary, to coat the titanium oxide thick.

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

Calcination temperature (. degree.C.)	Wear resistance	R₃₀(L)	R₃₀(D)	Antibacterial property (L)	Antibacterial property (D)
Calcination temperature (. degree.C.)	Wear resistance	R₃₀(L)	R₃₀(D)	Antibacterial property (L)	Antibacterial property (D)	300 400 500	◎ ◎ ◎	0％ 60％ 60％	0％ 0％ 3％	- + +	- - -

With respect to the odor resistance, the sample was placed in a cylindrical vessel having an initial concentration of methyl mercaptan of 2ppm and a diameter of 26cm X a height of 21cm, and irradiated with light from a distance of 8cm from the sample for 30 minutes by a 4W BLB fluorescent lamp, and the removal rate of methyl mercaptan (R) was measured₃₀(L))，And the methyl mercaptan removal rate (R) after 30 minutes in the dark was measured₃₀(D) Evaluation was performed.

The abrasion resistance was evaluated by performing sliding friction using a plastic rubber and comparing the change in appearance, and the evaluation indexes ◎, ○, △ and x in this case were the same as those described above.

For the antibacterial property, the test was carried out using Escherichia coli W3110 strain. 0.15ml (1-50000CFU) of the bacterial suspension was dropped onto the outermost surface of the multifunctional material sterilized with 70% ethanol in advance, and the resultant was placed on a glass plate (100X 100) and adhered to the outermost surface of the substrate to prepare a sample. After 30 minutes of irradiation with a white lamp (5200 lux), the irradiated sample and the bacterial suspension of the sample held under the dark condition were wiped with sterilized gauze and collected in 10ml of physiological saline to determine the survival rate of bacteria as an evaluation index. The evaluation indexes +++, ++, -are the same as above.

The firing temperature was 300 ℃ and showed good results of ◎ in the sliding test, except that R₃₀(L) is 0%. This is considered to be caused by not crystallizing from amorphous titanium oxide to anatase type.

The sliding test also showed good results of ◎ at 400 ℃ enabling the confirmation of anatase form by X-ray in synthetic experiments, but R₃₀(L) was also improved to 60%, and the antibacterial activity was also +. in addition, the sliding test showed good results of ◎ even at 500 ℃, but R was₃₀(L) was also increased to the extent of 60%.

When the temperature is further increased, soda-lime glass of the substrate is deformed at 550 ℃, and thus a multifunctional material cannot be produced.

Example 36

In order to further improve the photocatalytic characteristics of the sample obtained in example 35, metal particles were supported. The photocatalyst also performs a reduction reaction simultaneously with the oxidation reaction. If the reduction reaction is not performed, electrons are not consumed, the particles are charged, and the oxidation reaction cannot be performed. This can be considered as R in example 1₃₀(L) is limited to 60%. In order to prevent this, the metal particles are carried on the titanium oxide particles, and electrons are allowed to escape, thereby preventing charging.

The metal particles were supported by the following method. The metal salt solution was sprayed on the photocatalyst and irradiated with 20W BLB fluorescent lamp for 1 minute at a distance of 20 cm. In the metal salt solution, a 1 wt% ethanol solution of copper acetate was used for copper loading, and a 1/1 mixed solution of 1 wt% ethanol/water of silver nitrate was used for silver loading. After irradiation, the substrate was washed and dried. Instead of using an aqueous solution of a metal salt, a solution containing ethanol is used, which results in good wettability of the sample with the metal salt solution.

The thus obtained samples were evaluated for odor resistance, abrasion resistance, and antibacterial property. The results are shown in Table 20. In addition, only the samples obtained at a firing temperature of 500 ℃ were used. (watch 20)

Calcination temperature (. degree.C.)	Wear resistance	R₃₀(L)	R₃₀(D)	Antibacterial property (L)	Antibacterial property (D)
Calcination temperature (. degree.C.)	Wear resistance	R₃₀(L)	R₃₀(D)	Antibacterial property (L)	Antibacterial property (D)	500	◎	98％	98％	+++	++

The sliding test showed good results of ◎, and R₃₀The (L) dramatically increased to 98%. The antibacterial property is +++.

Comparative example 37

The same procedure was followed, except that no silica coating was performed in example 35. That is, titanium oxide coating was performed on soda lime glass of 10cm square. The results are shown in Table 21. (watch 21)

Calcination temperature (. degree.C.)	Wear resistance	R₃₀(L)	R₃₀(D)	Antibacterial property (L)	Antibacterial property (D)
Calcination temperature (. degree.C.)	Wear resistance	R₃₀(L)	R₃₀(D)	Antibacterial property (L)	Antibacterial property (D)	300 400 500	◎ ◎ ◎	0％ 0％ 0％	0％ 0％ 0％	- - -	- - -

As can be seen from Table 21, the sliding test showed good results of ◎ in the case of 300 deg.C, 400 deg.C and 500 deg.C, but R₃₀(L) even if the process from the titanium tetraethoxide coating film to firing is repeated 10 times, it is 0%, and the antibacterial property is-.

At 300 ℃, R₃₀The reason why (L) is inferior is considered to be that titanium oxide is not crystallized from amorphous titanium oxide into anatase type.

On the other hand, at 400 ℃ and 500 ℃, the titanium oxide has been crystallized from amorphous titanium oxide to anatase type, and R cannot be described for the above reason₃₀(L) is inferior. The reason is considered to be that soda-lime glass is soft due to the substrateAnd (4) forming, namely burying the titanium oxide film in the glass.

As is clear from the above description, even with a base material having a relatively low melting point, a multifunctional material having odor-resistant and antibacterial properties can be produced by the presence of the high melting point layer between the base material and the photocatalyst layer.

An example suitable for maintaining the photocatalytic effect on the surface of plastic or the like poor in heat resistance is described below.

The base material is not limited to any of plastic, ceramics, glass, composites thereof, and the like, which are inferior in heat resistance.

The shape of the base material may be any of a simple shape such as a spherical object, a cylindrical object, a tile, a wall material, a plate-like object such as a floor material, and the like, a complicated shape such as a sanitary ceramic, a sink, a bathtub, a sink, a toilet sheet, and the like, and the surface of the base material may be porous or dense.

The type of the binder may be inorganic glass, thermoplastic resin, soft solder, or other thermoplastic material, or may be fluororesin, silicone resin, or other thermosetting material. However, the photo-resistant material is preferable in that light including ultraviolet rays is irradiated in the subsequent process. In addition, in the case of only the heat treatment at 300 ℃ or lower, it is preferable that the thermoplastic material is a material capable of softening at 300 ℃ or lower and the thermosetting material is a material capable of curing at 300 ℃ or lower, from the viewpoint of the usefulness of the present application. As a material satisfying these conditions, boric acid-based glass, soft solder, acrylic resin, and the like can be given as a thermoplastic material, and fluorine resin, silicone resin, and the like can be given as a thermosetting material.

When a thermoplastic material is used as a method for applying these adhesive agent layers to a substrate, there are a spray coating method, a roll coating method, a dip coating method, and the like, and any of these methods may be used, or other methods may be used. In addition, the composition of the binder does not necessarily have to be consistent with the binder composition at the completion of the component. For example, when the binder is composed of an inorganic glass, the coating material may be a suspension of an inorganic glass composition such as a granular form, a frit form, a block form, or a powder form, or may be a mixture containing salts of the constituent metal components. When the binder is a resin, a resin solution having the above composition may be used, or other methods may be used.

The coated binder layer may be dried, moisture evaporated, etc., before the photocatalyst particles are coated on the binder layer. In this case, the drying method may be a method of leaving the substrate at room temperature or a method of heating the substrate.

Further, before the photocatalyst particles are coated on the adhesive layer, the coated adhesive layer may be heat-treated at a temperature lower than the softening temperature of the base material, at which the adhesive layer becomes the adhesive composition at the completion of the member and softens. According to this method, since the photocatalyst particles are formed on the binder layer more smoothly than the binder layer in advance, the photocatalyst particles can exhibit sufficient effects even when the amount of the photocatalyst particles to be coated is small.

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

The viscosity-increasing value is preferably 105 poise or more and 1075 poise or less. After a high viscosity value of 105 poise or more is formed, the photocatalyst particles are coated, whereby the photocatalyst particles may be buried in a state of not being completely buried in the adhesive layer, and further, since 1075 poise or less is formed, at least a part of the lowermost layer of the photocatalyst particle layer is buried in the adhesive layer.

The method of coating the photocatalyst particles on the surface of the binder layer is basically carried out by coating the binder layer with a material obtained by appropriately treating the starting material.

The starting material is preferably a sol suspension of the photocatalyst composition, but other fine particle suspensions of the photocatalyst composition may be used. In either case, it is necessary to add a surface treatment agent such as a dispersant so that the photocatalyst composition in the suspension does not aggregate in order to form a uniform coating film. The adhesive layer may be applied by a spray coating method, a roll coating method, a dip coating method, or the like, but any method may be used, and other methods may be used.

The thickness of the photocatalyst layer embedded in the adhesive layer is not less than 1/4, which is the thickness of the photocatalyst layer embedded in the adhesive layer, and the bonding strength with the substrate is satisfactory. The photocatalyst layer thickness is obtained by analyzing the component elements constituting the photocatalyst particles in the cross-sectional direction measured by EPMA or the like, and is composed of an upper layer part and an embedded part, in which the amount of the component elements constituting the photocatalyst particles is substantially constant, and the embedded part is located between the depth at which the amount of the component elements constituting the photocatalyst particles starts to decrease and the depth at which the amount of the component elements constituting the binder starts to become constant.

The surface treatment agent attached to the photocatalyst is mainly composed of a component added for dispersing the starting material sol of the photocatalyst particles. Specific examples thereof include pentaerythritol, trimethylolpropane, triethanolamine, trimethanolamine, silicone resins, alkylchlorosilanes, and the like.

As a solution containing 1.7mW/cm²Examples of the light source having a wavelength of 390nm or less include a BLB fluorescent lamp, an ultraviolet lamp, a germicidal lamp, a xenon lamp, and a mercury lamp.

Must be 1.7mW/cm²The reason why the wavelength of light having a wavelength of 390nm or less is that the dispersant component such as silicone resin has a certain degree of photo-corrosion resistance, and if the ultraviolet intensity is not at that degree, the dispersant component is not decomposed. In this case, the shorter the wavelength of ultraviolet light, the faster the dispersant is decomposed, but depending on the type of binder, the binder may be decomposed and harmful to the human body. Therefore, it may be 250nm or more. In addition, the illumination reaches 3mW/cm²In the case of the above method, the decomposition rate is accelerated with the increase of illuminance, but the decomposition rate is increased to 3mW/cm even when the illuminance is increased²The above does not contribute much to the improvement of the decomposition rate, so 3mW/cm²The following is sufficient.

The above process is schematically shown in fig. 47. On the substrate 1, a part of the lower layer of the photocatalyst layer 2 is embedded in the binder layer 6 through the binder layer 6. And 6a is a layer made of a surface treatment agent or the like which suppresses photocatalytic activity. UV represents 1.7mW/cm²Light having a wavelength of 390nm or shorter.

The following description will be made with respect to the formation of a layer mainly composed of the photocatalyst particles 3 and the thermosetting resin 6 on the surface of the base material, and exposure of the photocatalyst layer by similarly irradiating ultraviolet rays. (refer to FIG. 48) in this method, the photocatalyst particles 3 were firmly fixed to the substrate using a thermosetting resin, and the irradiation content was 1.7mW/cm²Light having a wavelength of 390nm or less causes a photocatalytic reaction at a light irradiated portion on the surface of the photocatalyst particle, thereby bringing the photocatalyst particle into a state of being irradiated with lightThe surface treatment agent and the thermosetting resin in the direction of the light source are decomposed and gasified preferentially to expose the photocatalyst particles in the air, and therefore, sufficient photocatalytic activity can be obtained.

In addition, a method of forming a layer mainly composed of photocatalyst particles and a thermosetting resin includes, for example, adding a thermosetting resin, a diluent, and a curing agent in this order to a sufficiently dispersed photocatalyst sol suspension to obtain a mixed solution, applying the mixed solution to the surface of a substrate, and performing a heat treatment.

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

The thermosetting resin used here preferably has light-resistance to white light and light of an ordinary fluorescent lamp intensity. This is because of excellent durability in use. In this sense, silicone resins, fluorine greases, are particularly desirable.

The diluent is used to reduce the viscosity of a mixed solution composed of a photocatalyst sol and a thermosetting resin, so that the mixed solution can be easily applied to the surface of a substrate. However, the diluent used herein can be basically used as long as it is a solvent for achieving the purpose. For example, water, ethanol, propanol, etc. may be used.

The method of applying the mixed liquid to the substrate may be a spray coating method, a roll coating method, a dip coating method, a spin coating method, or the like, but any of these methods may be used, or other methods may be used.

The heat treatment furnace is generally an electric furnace, a gas furnace, a vacuum furnace, a pressure furnace, or the like, 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 by a thermosetting resin layer or a photocurable resin layer (intermediate layer: C) (see fig. 49).

According to this method, even if the substrate has irregularities or the like, the thermosetting resin layer or the photocurable resin layer disposed between the substrate and the photocatalyst layer forms an extremely smooth surface before the photocatalyst layer is applied, and therefore a uniform photocatalyst layer can be easily formed. Further, since the thermosetting resin layer or the photocurable resin layer disposed between the substrate and the photocatalyst layer sufficiently bonds to the substrate, even if the surface of the substrate has irregularities, the layer composed of the photocatalyst particles and the thermosetting resin can be thinly formed and the photocatalyst particles can be concentrated in the vicinity of the surface of the substrate, and thus irradiation with 1.7mW/cm can be carried out in a shorter time to complete the subsequent process²And light irradiation process of light with wavelength of 390nm or less. In addition, since the above layer composed of the photocatalyst particles and the thermosetting resin is present, even if it is decomposed or vaporized in the subsequent process or in use, ultraviolet rays having a sufficient intensity cannot reach the thermosetting resin layer or the photocurable resin layer disposed therebetween, and thus the thermosetting resin can be arbitrarily selected for this portion. For example, an inexpensive epoxy resin may be selected for cost reduction, and a colored resin may be used for maintaining the pattern.

Here, a method of forming the thermosetting resin layer disposed between the substrate and the photocatalyst layer includes, for example, applying a mixed solution obtained by adding a diluent and then a curing agent to a thermosetting resin, and curing the mixture by heat treatment or leaving it. When the layer disposed in the middle of the photocatalyst is a photocurable resin layer, irradiation with light containing ultraviolet rays is used instead of the heat treatment. Here, in order to reduce the viscosity of the mixed liquid, the mixed liquid is easily applied to the surface of the substrate, and a diluent is added thereto. Therefore, the diluent used herein may be basically any solvent as long as it can achieve the purpose. For example, water, ethanol, propanol, etc. may be used.

Further, as shown in FIGS. 50(a) and (b), according to the above method, it is preferable to fill the gaps formed on the photocatalyst layer exposed on the surface of the base material with particles (gap particles: 4) smaller than the gaps, so that the abrasion resistance can be further improved.

The particle size smaller than the gap may be substantially smaller than the average value of the pore diameters and the irregularities to be generated, and the amount of the particles smaller than the gap is preferably about 20% or less of the open pore ratio to be added to the surface. Because the contamination is difficult to attach.

Specific examples are given below.

Example 38

A mixed solution prepared by adding 10% by weight of a titanium oxide sol (obtained by dispersing a titanium oxide sol with an amine dispersant) having an average particle size of 0.01 μm to the surface of a 10cm square alumina substrate in this order and then adding a silicone resin, a diluent and a curing agent in this order was applied to the surface of the substrate, and the resultant was baked at 150 ℃ to obtain a comparative sample. The sample was irradiated with various light sources for a predetermined time to obtain a sample. The obtained sample was evaluated for odor resistance R upon light irradiation₃₀(L)。

Here, the odor resistance R at the time of light irradiation₃₀(L) is a concentration change rate after 30 minutes of irradiation of a 11 liter glass container in which the sample surface was placed at a distance of 8cm from the light source (BLB fluorescent lamp, 4W), methyl mercaptan was injected into the container at an initial concentration of 3 ppm.

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

Light source	Ultraviolet intensity (W/cm)²)	Irradiation time (day)	R₃₀(L)(％)
Light source	Ultraviolet intensity (W/cm)²)	Irradiation time (day)	R₃₀(L)(％)	Is free of BLB BLB Ultraviolet lamp Ultraviolet lamp	- 0.3 1.69 2.0 3.0	- 7 5 3 1	30 32 52 74 82

As a result, the ultraviolet intensity was 1.69mW/cm²The above odor resistance is over 50%, and is 2mW/cm²Above, odor resistance R₃₀(L) is a good result of more than 70%. Here, the ultraviolet intensity was 1.69mW/cm²The above results are good, and it can be explained that the photocatalytic reaction occurs in the light irradiation part on the surface of the photocatalytic particle, the thermosetting resin in the direction of the surface treatment agent and the light source is preferentially decomposed and gasified, and the photocatalytic particle is exposed to the airFor the reason of (1).

Example 39

A solution prepared by adding a diluent and a curing agent to a silicone resin was applied to the surface of a 10cm square alumina substrate, dried at room temperature for about 6 hours, then applied to a titanium oxide sol having an average particle size of 0.01 μm (obtained by dispersing with an amine-based dispersant) and mixed with 10% by weight of a silicone resin, a diluent and a curing agent in this order, and then baked at 150 ℃ to obtain a comparative sample. The sample was irradiated with various light sources for a predetermined time to obtain a sample. The obtained sample was evaluated for odor resistance R upon light irradiation₃₀(L)。

The results are shown in Table 23. (watch 23)

Light source	Ultraviolet intensity (W/cm)²)	Irradiation time (day)	R₃₀(L)(％)
Light source	Ultraviolet intensity (W/cm)²)	Irradiation time (day)	R₃₀(L)(％)	Is free of BLB BLB Ultraviolet lamp Ultraviolet lamp	- 0.3 1.69 2.0 3.0	- 7 5 3 1	34 38 61 82 84

As a result, the ultraviolet intensity was 1.69mW/cm²Above, the deodorization performance exceeds 60 percent and is 2mW/cm²Above, odor resistance R₃₀(L) is a good result of more than 80%. Here, the ultraviolet intensity was 1.69mW/cm²The above results are excellent, and it can be explained that the photocatalytic reaction occurs in the light irradiated portion of the surface of the photocatalytic particle, whereby the surface treatment agent adhering to the light irradiated surface of the photocatalytic particle surface that is not gasified or decomposed by the heat treatment can be decomposed and gasified preferentially, and as a result, the photocatalytic particle is exposed to the air.

Example 40

In the square of 10cmThe surface of the alumina substrate is coated with a solution prepared by adding a diluent and a curing agent to a silicone resin, dried at room temperature for about 6 hours, and then coated on the average particleA mixed solution obtained by adding 10% by weight of a silicone resin, a diluent and a curing agent in this order to a titanium oxide sol (obtained by dispersing a titanium oxide sol having a diameter of 0.01 μm with an amine-based dispersant) was calcined at 150 ℃. The average particle size on the surface of the member at this stage is about 0.1 to 0.2. mu.m. Then, the ultraviolet intensity was 2mW/cm²After 3 days of irradiation with light (ultraviolet lamp), R was confirmed₃₀(L) more than 80%, and then the surface of the sample was coated with a titanium oxide sol having an average particle size of 0.0035 μm in an amount of 70% by weight based on the weight of the titanium oxide sol and dried at 110 ℃. Also in this sample, R is shown₃₀(L) is a good result of 81%. In addition, in the sliding test using the plastic eraser, the sample to which tin oxide was not added was scratched and titanium oxide was peeled off after 5 times or less of sliding, but the sample to which tin oxide was added was not changed even after 10 times or more of sliding. From the above, it was confirmed that the wear resistance can be improved by filling the gaps formed on the surface of the member with tin oxide particles smaller than the gaps.

As is apparent from the above description, even in the case where a layer having a photocatalytic effect is formed by treatment at 300 ℃ or lower, a member having good photocatalytic activity can be provided.

Next, although the same purpose as the exposure by ultraviolet irradiation is achieved, a method of providing a multifunctional material having a sufficient photocatalytic effect even when firing is performed at 300 ℃ or lower is described below by a different means.

In this method, metal fine particles are fixed on the surface of a titania sol prepared by a hydrothermal method, a sulfuric acid method or the like, before a surface treatment agent such as a dispersant, a surfactant or the like is added to the titania sol.

The metal fine particles herein mean metal fine particles capable of capturing electrons when irradiating titanium oxide with light to generate electrons and holes, and specifically means Ag, Cu, Pt, Pd, Ni, Fe, Co, and the like, when supported on titanium oxide.

The photoreduction method is simple and convenient in the method of fixing metal fine particles on the surface of titanium oxide sol. The titania sol used herein is desirably prepared by a hydrothermal method or a sulfuric acid method, but is not limited thereto. The sulfuric acid method is a synthesis method of titanium oxide by the procedure shown below.

First, anatase is reacted with sulfuric acid to convert Ti, Fe, etc. into water-soluble sulfate, and the sulfate solution containing Ti and Fe as main components is prepared by extraction with water. Followed by SiO removal₂And the like in insoluble suspended matter. Then cooling to 10-15 ℃, separating out ferric sulfate, and separating and removing. Subsequently, the titanium oxysulfate in the solution is hydrolyzed to produce titanium hydroxide. The obtained titanium hydroxide-containing sol is crystallized by hydrothermal treatment in a high-temperature high-pressure water (generally, a saturated steam pressure of 110 ℃ to 200 ℃) using a pressure apparatus such as an autoclave to obtain a titanium oxide sol.

The hydrothermal method is a method of obtaining a titania sol by subjecting a titanium source such as titanium tetrachloride or titanium sulfate to hydrothermal treatment under high temperature and high pressure water (generally, under a saturated vapor pressure of 110 ℃ to 200 ℃) using a pressure apparatus such as an autoclave and hydrolyzing the treated solution.

The method of fixing metal fine particles to the surface of a titanium oxide sol by the photoreduction method will be described in detail below.

First, a titanium oxide suspension prepared by a hydrothermal method or a sulfuric acid method is made acidic or alkaline. Titanium oxide has an isoelectric point of pH6.5 and is neutral, so that it is easily aggregated. Further, ammonia is preferably used for the purpose of adjusting the basicity. Alkali metals such as Na and K tend to strongly adhere to titanium oxide, and if these metals occupy the active sites of titanium oxide first, the photocatalytic activity is reduced, and at the same time, the adhesion of Ag, Cu, Pt, Pd, Ni, Fe, Co, and the like to the active sites of titanium oxide is inhibited.

Subsequently, the titanium oxide sol suspension and a metal salt solution having substantially the same pH are mixed to form a titanium oxide sol suspension, and the titanium oxide sol suspension is irradiated with light containing ultraviolet rays to fix the metal. Excess metal is precipitated and removed from the solution if necessary. The metal salt solution as used herein refers to a solution comprising a solvent and a metal salt capable of capturing electrons when the titanium oxide is irradiated with light to generate electrons and holes, and more specifically, a solution comprising a solvent and a salt of Ag, Cu, Pt, Pd, Ni, Fe, Co, or the like, when the titanium oxide is supported on the titanium oxide. Examples of the salt containing Ag, Cu, Pt, Pd, Ni, Fe, Co, and the like include silver nitrate, copper acetate, copper carbonate, copper sulfate, cuprous chloride, cupric chloride, chloroplatinate, palladium chloride, nickel chloride, cobalt chloride, ferrous chloride, ferric chloride, and the like. The solvent may be water, ethanol, propanol, or the like, but the same kind of solvent as the titanium oxide sol suspension to be formed may be used. A pH adjuster is added to the solvent as needed. As the pH adjusting agent to the acid side, nitric acid, sulfuric acid, hydrochloric acid, or the like can be used. Further, ammonia was used as a pH adjuster to the alkali side.

When light containing ultraviolet rays is irradiated, the following points are noted. First, the light source may be a light source that irradiates light containing ultraviolet rays. Specific examples thereof include an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, and a fluorescent lamp. The method of irradiating light containing ultraviolet rays is basically not problematic, but irradiation from above the container is possible at first. Since no container absorbs uv light. Secondly the distance of the light source from the container may be in the order of a few cm to a few 10 cm. If it is too close, the solution may be dried due to heat emitted from the light source, and if it is too far, the illuminance may be lowered. The irradiation time varies depending on the illuminance of the light source, and when the irradiation is performed for several seconds to several tens of seconds, the metal is firmly attached to the photocatalyst particles.

Then, a film formed by applying a titanium oxide sol supporting the above metal and heat-treating the applied titanium oxide sol is formed on the surface of the base material, thereby forming a multifunctional material having a photocatalytic effect.

The heat treatment is usually carried out by calcination in the atmosphere using an electric furnace, a gas furnace, or the like, or hydrothermal treatment using an autoclave or the like, but is not limited thereto.

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

Further, a film formed by applying the sol of claim 1 on the surface of a substrate with a binder and performing a heat treatment is formed to obtain a member having a photocatalytic effect. By using the binder, the adhesiveness to the base material can be improved.

The specific method differs depending on whether the binder is a thermoplastic binder or a thermosetting binder. Each of the embodiments shown below satisfies the above-described configuration, and it goes without saying that other methods may be used. Specific examples of the thermoplastic adhesive include thermoplastic adhesives such as acrylic resins, inorganic glasses such as glazes, and soft solders. Examples of the thermosetting binder include a fluororesin, an epoxy resin, and a silicone resin.

When a thermoplastic binder is used, a member having a photocatalytic effect is produced in the following order. A thermoplastic binder is first coated on the surface of the substrate. Subsequently, a titanium oxide sol supporting metal particles is applied thereon, and heat treatment is performed. The heat treatment is carried out at a temperature lower than the heat-resistant temperature of the base material and higher than the softening point of the thermoplastic binder. By performing the heat treatment at such a temperature, the lower layer of the titanium oxide layer supporting the metal particles is partially embedded in the binder layer, whereby the base material and the titanium oxide film supporting the metal particles can be firmly bonded.

In addition, when a thermosetting adhesive is used, a member having a photocatalytic effect is produced in the following order. First, a diluent and a curing agent are sequentially added to a thermosetting binder to prepare a mixed solution, and the mixed solution is coated on a substrate and cured by a method such as heat treatment. Then, a mixed solution prepared by sequentially adding a thermosetting resin, a diluent, and a curing agent to the metal particle-supporting titania sol is applied thereto, and cured by a method such as heat treatment.

Further, instead of the thermosetting adhesive, a photocurable adhesive may be used in the same manner.

In this way, in the titania sol produced by a hydrothermal method, a sulfuric acid method or the like, before a surface treatment agent such as a dispersant, a surfactant or the like is added, metal particles such as Ag, Cu, Pt, Pd, Ni, Fe, Co or the like are fixed to TiO₂On the surface of the sol, metal particles of Ag, Cu, Pt, Pd, Ni, Fe, Co, etc. are used in advanceThe active sites of the titania sol are covered, and even if a surface treatment agent such as a dispersant or a surfactant is added in the subsequent process, these substances are adsorbed on the active sites of the titania sol and do not lose their activity. Therefore, the photocatalyst sol can be stably dispersed by the action of a surface treatment agent such as a dispersant or a surfactant to form a homogeneous film on the surface of the substrate, and at the same time, even if the photocatalyst sol is baked at a low temperature of 300 ℃ or lower, the decrease in the photocatalytic action caused by adsorption of the surfactant such as a dispersant or a surfactant to the active sites of the photocatalyst particle layer formed on the surface of the substrate can be prevented, and the photocatalyst sol can be stably dispersed by Ag, Cu and the like occupying the active sites of the titanium oxide sol,The effect of capturing electrons of metal particles such as Pt, Pd, Ni, Fe, Co and the like improves the photocatalytic activity.

Specific examples are given below.

EXAMPLE 41

Water was added to titanium tetrachloride in a cold water bath to obtain a liquid, and the obtained liquid was subjected to hydrothermal treatment in an autoclave at 140 ℃ to obtain an anatase-type titanium oxide sol. The obtained anatase-type titania sol was dispersed in nitric acid. The pH of the dispersion was 0.8. To the dispersion, a 3 to 5 wt% copper sulfate aqueous solution adjusted to pH of about 0.8 with nitric acid was added, and the mixture was irradiated with ultraviolet-containing light from above the container. At this time, the light source was irradiated with 4W of 8LB lamp for 15 minutes from a distance of about 10cm from the solution. A dispersant composed of an organic acetate is added to the solution to stabilize the sol. The sol was applied to a 15cm square tile substrate and heat-treated at 150 ℃ to obtain a sample. The obtained sample was measured for odor resistance R upon irradiation with light₃₀(L) and antibacterial properties.

Odor resistance R upon light irradiation₃₀(L) is a concentration change rate after irradiating a sample placed in a glass container of 11 liters at a distance of 8cm from a light source (BLB fluorescent lamp, 4W) with methyl mercaptan gas at an initial concentration of 3ppm for 30 minutes by injecting the gas into the container.

In addition, regarding the antibacterial properties, the test was carried out using Escherichia coli (Escherichia coli W3110 strain). 0.15ml (10000-50000CFU) of the bacterial solution was dropped onto the outermost surface of the sample previously sterilized with 70% ethanol, and the sample was placed on a glass plate (100X 100) so as to be in close contact with the outermost surface of the substrate. After 30 minutes of irradiation with a white lamp (3500 lux), the bacterial solution of the irradiated sample was wiped with a sterilized gauze and collected in 10ml of physiological saline, and the survival rate of bacteria was determined as an evaluation index. The evaluation criteria +++, ++, -are the same as described above.

Results R₃₀(L) showed good results of 85%, and the antibacterial activity showed good results of +++ respectively.

Comparative example 42

In a cold water bath, water was added to titanium tetrachloride to obtain a liquid, and the obtained liquid was subjected to hydrothermal treatment in an autoclave at 140 ℃ to obtain an anatase-type titanium oxide sol. The obtained anatase-type titania sol was dispersed in nitric acid. The pH of the dispersion was 0.8. Adding a dispersant composed of organic acetate into the solution to stabilize the sol, coating the sol on a tile substrate of 15cm square, performing heat treatment at 150 deg.C to obtain a sample, and measuring odor resistance R of the sample under light irradiation₃₀(L) and antibacterial properties.

Results R₃₀(L) is 5%, and the antibacterial property is-all of them are insufficient.

Example 43

In a cold water bath, water was added to titanium tetrachloride to obtain a liquid, and the obtained liquid was subjected to hydrothermal treatment in an autoclave at 140 ℃ to obtain an anatase-type titanium oxide sol. The obtained anatase-type titania sol was dispersed in nitric acid. The pH of the dispersion was 0.8. To this solution, a 3 to 5 wt% aqueous solution of copper sulfate adjusted to pH of approximately 0.8 with nitric acid was added, and the vessel was irradiated with ultraviolet-containing light from above. At this time, the light source was irradiated with 4W BLB light for 15 minutes from a distance of about 10cm from the solution. A dispersant composed of an organic acetate is added to the solution to stabilize the sol. Next, a mixture of a diluent propanol and a curing agent sequentially added to a silicone resin was applied to the surface of a 10cm square alumina substrate, and the sol prepared as described above was applied to a member dried at 100 ℃To the mixture was added 20% by weight of a silicone resin, propanol and a curing agent in this order, and the mixture was calcined at 150 ℃ to obtain a sample. The obtained sample was measured for odor resistance R upon irradiation with light₃₀(L) evaluation.

Results R₃₀(L) shows good results of 80%.

Comparative example 44

In a cold water bath, water was added to titanium tetrachloride to obtain a liquid, and the obtained liquid was subjected to hydrothermal treatment in an autoclave at 140 ℃ to obtain an anatase-type titanium oxide sol.The obtained anatase-type titania sol was dispersed in nitric acid. The pH of the dispersion was 0.8. Adding a dispersant composed of organic acetic acid to the solution to stabilize the sol, applying a mixture prepared by adding a thinner propanol and a curing agent in order to a silicone resin on the surface of a 10cm square alumina substrate, applying a mixture prepared by adding a silicone resin, a propanol and a curing agent in order to the above-mentioned sol prepared by the above-mentioned method on a member dried at 100 ℃, baking the mixture at 150 ℃ to obtain a sample, and measuring the odor resistance R at the time of light irradiation on the sample₃₀(L). Results R₃₀The content of (L) was 22%, which was not sufficient.

As is clear from the above description, in a titania sol prepared by a hydrothermal method, a sulfuric acid method or the like, metal particles of Ag, Cu, Pt, Pd, Ni, Fe, Co or the like are fixed on the surface of the titania sol before a surface treatment agent such as a dispersant, a surfactant or the like is added, and thus, even when firing is performed at a low temperature of 300 ℃ or less, a member having a sufficient photocatalytic effect can be provided on a heat-labile substrate, for example, a plastic material.

The above examples have been described primarily with respect to anatase TiO₂The following description is about rutile type TiO₂。

FIG. 51 shows the use of rutile type TiO₂The present invention first forms rutile type TiO on the surface of a substrate such as a ceramic tile₂A film. As gold redStone type TiO₂Method for forming thin film by using TiO as raw material₂Sol, alkoxy titanium, sulfate of Ti, chloride solution of Ti, etc., is coated on the substrate, and then heat-treated.

In the use of TiO₂When sol, because of TiO₂The isoelectric point is 6.5, and the coating is almost neutral, so that the coating can be easily and uniformly applied to a substrate using an aqueous solution dispersed with an acid or an alkali. When the substrate is a metal, the alkali dispersion is preferable from the viewpoint of corrosion resistance. Examples of the acid include sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, and organic acids. In the case of alkali, ammonia, alkali metal-containing hydroxides, etc. can be mentioned, and ammonia is particularly preferred since it does not generate metal contaminants after heat treatmentIdeally, it is desirable. Further, an organic acid, a phosphoric acid-based dispersant, a surface treatment agent, and a surfactant may be further added to these dispersions. Further, when the particle size is small, initial sintering occurs at a lower temperature, and a photocatalyst thin film excellent in peel strength can be obtained at a low temperature, so that TiO₂The average particle diameter of the sol may be 0.05 μm or less, preferably 0.01 μm or less.

As a method for applying the coating film to a substrate, it is desired to form a stable coating film without requiring any special equipment as compared with spraying, dipping, roll coating, spin coating, CVD, electron beam evaporation, sputtering, or the like of the above-mentioned raw materials.

The heat treatment may be carried out by atmospheric firing using an electric furnace or a gas furnace or hydrothermal treatment using an autoclave.

On the other hand, Cu, Ag, Fe, Co, Pt, Ni, Pd, Cu are prepared in advance₂At least one solution (aqueous solution containing metal ions) of O, and the solution is coated on rutile TiO₂On the film. Here, when the metal salt aqueous solution is applied, the metal salt aqueous solution is not transferred to the back surface of the substrate. The solution in the metal salt solution may use water, ethanol, or the like. When water is used, it is also effective to add an alcohol, an unsaturated hydrocarbon, or the like as a protective oxidizing agent. Furthermore, the ethanol solution is used as a solution, and is mixed with ether, acetone, methanol, etc. in order to prevent rust from being generated on the metal substrate and increase the drying speedOther solvents are less hazardous than others, which is desirable.

Then, in order to improve the efficiency of supporting the metal salt aqueous solution, the metal salt is dried at room temperature to 110 ℃, light with a wavelength of 390nm or less is irradiated to the metal salt, metal ions are reduced, and the metal is precipitated and fixed on rutile TiO₂On the film. Here, as the lamp for irradiation, an ultraviolet lamp, a BLB lamp (near ultraviolet) lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, or the like can be used. In this case, in order to increase the irradiation rate, light may be irradiated perpendicularly to the irradiation surface.

Specific examples are given below

Example 45

Coating on 10cm square alumina substrate with average particle size of 0.01 μm by spray coatingOf TiO 2₂Calcining the sol in ammonia dispersion at 900 deg.C to form rutile TiO₂A film. Then, in the rutile type TiO₂On the film, an aqueous solution of copper acetate was applied by spray coating, followed by photoreduction (light source 20W BLB lamp, distance from light source to sample 10cm, irradiation time 10 seconds) to obtain a sample. The resulting sample was evaluated for photoactivity A (L).

The photoactivity A (L) represents the absolute value of the slope when the reaction curve with the gas concentration on the Y axis and the reaction time on the X axis is approximated to a straight line. That is, if the concentration at time t is Xt, the

Xt＝X₀·10^-A(L)t(1) Therefore, the light containing ultraviolet rays passes through the irradiated photocatalyst thin film, and the concentration of the decomposition gas is observed to decrease with the lapse of time t, whereby a certain decomposition gas is determined. In this experiment, methyl mercaptan which is a malodorous component in the decomposed gas was used, a sample was placed in a cylindrical container having an initial concentration of methyl mercaptan adjusted to 2ppm and a diameter of 26cm × a height of 21cm, a 4W BL8 fluorescent lamp was set at a distance of 8cm from the sample, and the decomposed gas was determined by observing the change in the concentration of methyl sulfate with time when irradiated with light.

The obtained results are shown in fig. 52 and 53. Fig. 52 and 53 are graphs showing the relationship between the Cu concentration in the solution and the photoactivity a (l), in which fig. 52 shows the case where the atomized copper acetate aqueous solution is dried and then subjected to photoreduction, and fig. 53 shows the case where the atomized copper acetate aqueous solution is subjected to photoreduction without being dried.

In the case of carrying out the photoreduction of the aqueous copper acetate solution in the state not subjected to drying as it was atomized in FIG. 53, A (L) was 3X 10 even if the Cu concentration in the solution was increased from 0.001% by weight to 0.1% by weight^-5Degree, unchanged, saturation was reached.

In contrast, in the case where the atomized aqueous copper acetate solution of FIG. 52 was dried and then subjected to photoreduction, the concentration was 2X 10 at 0.001 wt%^-5The degree of the drying was about the same as that in the case where the drying was not conducted, but when the amount was increased to 0.1 wt%, the degree reached 1X 10^-2The degree of A (L) dramatically increased.

Example 46

Rutile TiO was formed on floor tiles and wall tiles in the same manner as in example 45₂A thin film in which Cu (aqueous solution of copper acetate) is applied by photo-reduction and dried to fix the film to the rutile TiO₂In the case of a film, the concentration of metal components in the solution and the odor removal rate R₃₀Fig. 54 and 55 show the detection results of the relationship (a).

From these figures, it is understood that, when the metal component concentration in the solution is increased to a certain degree by the photoreduction treatment after drying, the malodorous component can be removed even when the base material is a tile.

Example 47

Coating TiO with average particle size of 0.01 μm on a tile substrate of 15cm square by spray coating₂Calcining the ammonia dispersion of the sol at different temperatures to form rutile TiO₂A film. Then in the rutile form of TiO₂On the film, an aqueous solution of copper acetate was applied by spray coating, followed by photoreduction (light source: 20W BLB lamp, distance from light source to sample 10cm, irradiation time 10 seconds) to obtain a sample. The obtained sample was evaluated for odor resistance R₃₀。

The results obtained are shown in fig. 56. At 900 deg.C (open porosity 10%)R of (A) to (B)₃₀The value is better than that of the sample of rutile type alone which does not carry the metal. When the temperature was increased to 1000 ℃ (open porosity: 30%), R of the sample not carrying the metal was measured₃₀The values decreased significantly, with some decrease observed even with the Cu added samples. Therefore, there are two reasons why the odor resistance is lowered at 1000 ℃ as compared with that at 900 ℃. One is rutile TiO which is a photocatalyst capable of contacting with a decomposed gas with a decrease in open pore ratio₂The film area is reduced. This is considered to be a cause of deterioration in the odor-preventing property of the metal specimen not carried. Still another reason is that, along with the decrease in open porosity, the area in which metal particles can be deposited by the photoreduction method also decreases. Since the mean free path in the electron movement becomes large.

Fig. 57 shows the relationship between Ag and Cu concentrations in the solution and the color difference in the coating. From this figure, Cu is less in color difference and luminance change than Ag, and is not significantly colored. In addition, since the difference in coloring is detected by analysis such as ESCA (electron beam spectroscopy for chemical analysis) for Cu as 0-valent and 1-valent substances, it is considered that the difference is an influence of a 1-valent component which is not easily colored.

Example 48

Coating TiO with average particle size of 0.01 μm on a tile substrate of 15cm square by spray coating₂Calcining the ammonia dispersion of the sol at different temperatures to form rutile TiO₂A film. Then, an aqueous silver nitrate solution was applied to the rutile TiO by spray coating₂After that, photoreduction was carried out on the film (light source was a 20W BLB lamp, distance from the light source to the sample was 10cm, irradiation time was 10 seconds) to obtain a sample. With respect to the obtained sample, rutile type TiO₂Fig. 58 shows the evaluation results of the porosity, the odor resistance, and the abrasion resistance of the film.

When the porosity is 10% or more, good deodorizing property is exhibited, and when the porosity is 40% or less, the abrasion resistance can be 0 or more.

The abrasion resistance was evaluated by comparing the change in appearance by sliding friction using a plastic rubber. The evaluation index is shown below.

◎ No change in comparison with 40 times of repetition

○ scratching and peeling of titanium oxide film occurred in 10 to 40 sliding times

△ scratching and peeling of titanium oxide film occurred in 5 to 10 sliding times

X: the sliding was scratched 5 times or less, and the titanium oxide film was peeled off.

Example 49

On a 10cm square alumina substrate with a pre-formed glaze layer, TiO with an average particle size of 0.01 μm was applied by spraying₂Calcining the ammonia dispersion of the sol at a temperature of between 850 ℃ and 1000 ℃ to form rutile TiO₂A film. Then, in the rutile type TiO₂The film was coated with an aqueous silver nitrate solution by spray coating, and then subjected to photoreduction (20W BLB lamp, distance from the light source to the sample of 10cm, irradiation time of 10 seconds) to obtain a sample.

The obtained samples were evaluated for antibacterial property, abrasion resistance, peeling resistance, stain resistance, acid resistance, alkali resistance, and silver staining property.

For the antibacterial property, the test was carried out using Escherichia coli (Escherichia a coli W3110 strain). 0.15ml of a bacterial solution was dropped onto the outermost surface of the multifunctional material sterilized in advance with 70% ethanol, and the resulting solution was placed on a glass plate (100X 100) and adhered to the outermost surface of the substrate to prepare a sample. After 30 minutes of irradiation with a white lamp (3500 lux), the irradiated sample and the bacterial suspension of the sample held under a dark condition were wiped with a sterilized gauze and collected in 10ml of physiological saline, and the survival rate of bacteria was determined as an evaluation index. The evaluation indexes +++, ++, -are the same as those described above.

The peel resistance test is a test under severer conditions than the abrasion resistance test, and a sand rubber (LION TYPEWRITER ERASER 502) having a larger shearing force is used instead of the plastic rubber. The specific evaluation method was to rub a surface of a sample with a sand eraser with a uniform force 20 times and visually check the state of scratches compared with a standard sample, and the evaluation criteria are shown below.

◎ no change at all

○ confirmation of slight change by light addition and subtraction

△ confirmation of slight variations

X: confirm the change at a glance

The stain resistance test is a test concerning the difficulty of adhesion of stains. Specifically, the surface of the sample was stained with a 0.5% methylene blue aqueous solution, dried, washed with water, and the presence or absence of the stains was visually observed. The evaluation criteria are shown below.

◎ complete removal of dirt

○ although the color of the dirt is not clear, a small amount of residue remains

△ slight residual stain color

X: apparent residual stain color

Regarding the acid resistance, after the immersion in 10% HCl aqueous solution for 120 hours, the surface of the substrate was visually observed to support the rutile TiO form of Ag₂The evaluation was carried out based on the abnormal change of the thin film layer. The evaluation criteria are shown below.

◎ No change

○ very slight discoloration

△ slight discoloration

X: obvious color change

Regarding alkali resistance, the substrate was immersed in a 5% NaOH aqueous solution for 120 hours, and the surface of the substrate was visually observed for Ag-supporting rutile TiO₂The evaluation was made based on the abnormal change in the thin film layer, and the evaluation criteria are shown below.

◎ No change

○ very slight discoloration

△ slight discoloration

X: obvious and discolored

Silver staining was evaluated by visual comparison with a sample to which no Ag was added. The evaluation criteria are shown below.

◎ no coloring

○ very slight coloring

△ slight coloring

X: coloured part having brown colour

The above 7 evaluation results are summarized in Table 24. The effects of the film thickness and the baking temperature on the antibacterial property are shown in table 25. (watch 24)

Relationship between photocatalyst film thickness and characteristics

Film thickness (mum)	Antibacterial property (L)	Wear resistance	Resistance to peeling	Stain resistance	Acid resistance	Alkali resistance	Coloring property of Ag
Film thickness (mum)	Antibacterial property (L)	Wear resistance	Resistance to peeling	Stain resistance	Acid resistance	Alkali resistance	Coloring property of Ag	0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0	+++ +++ +++ +++ +++ +++ +++ +++ +++ +++	◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ×	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ×	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ×
No scratch (U.4)		△						0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0	+++ +++ +++ +++ +++ +++ +++ +++ +++ +++	◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ×	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ×	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ○	◎ ◎ ◎ ◎ ○ ○ ○ ○ ○ ×

(watch 25)

Influence of film thickness and baking temperature on antibacterial property of photocatalyst thin film

The antibacterial property was shown in the range of 0.1 μm to 1 μm in thickness of the photocatalyst film produced in this example, and when the calcination temperature was set to be appropriate, the result was good at + + + value. However, as shown in Table 24, the antibacterial properties of the samples baked at 980 ℃ were ++, when the film thickness was as thin as 0.2 μm or less. The antibacterial activity tends to be lowered. This is presumably because the photocatalyst thin film is locally buried in the scratch layer due to softening of the glaze layer. In addition, although Ag itself has antibacterial activity, the antibacterial activity of the composite member produced by the method of the present invention is liable to depend on the baking temperature, and the antibacterial activity of the composite member shows rutile TiO activity other than the antibacterial activity with Ag₂The film characteristics are relevant (because Ag is supported after firing as described above).

In all the samples, it is considered that the photocatalyst thin film sinks to the glaze layer to some extent with the softening of the glaze layer, but it was confirmed in the present example that the photocatalyst thin film of at least 0.1 μm or more can be held on the outermost layer of the glaze layer by setting the baking temperature to an appropriate value.

The photocatalyst thin film produced in this example showed good results of ◎ in both the film thickness ranges of 0.1 μm or more and 1 μm or less, which results were extremely good results, unlike △, which is a sample produced by the same production method for comparison without intermediate glaze, this is considered to be because the intermediate glaze was interposed and a part of the lower layer of the photocatalyst thin film was buried in the glaze layer due to softening of the glaze at the time of firing.

On the other hand, in the peeling resistance test, ◎ was observed when the thickness was 0.1 μm or more and 0.4 μm or less, ○ was observed when the thickness was 0.4 μm or more and 0.9 μm or less, and x was observed when the thickness was 1 μm, and a tendency was observed that the film thickness of the photocatalyst thin film was increased and the film was deteriorated.

Regarding the stain resistance, ◎ was observed when the thickness of the photocatalyst thin film was 0.1 μm or more and 0.4 μm or less, ○ was observed when the thickness was 0.4 μm or more and 0.9 μm or less, and x was observed when the thickness was 1 μm, and the film tends to deteriorate as the thickness of the photocatalyst thin film increased.

The photocatalyst thin films produced in this example showed good results in terms of acid resistance in the range of 0.1 μm to 1 μm both inclusive, however, ○ was observed in the range of 0.4 μm to 1 μm inclusive, ◎ was observed in the range of 0.1 μm to 0.4 μm inclusive, and the thin films showed satisfactory values.

However, ○ was found to be between 0.4 μm and 1 μm, ◎ was found to be between 0.1 μm and 0.4 μm, and a satisfactory value was found for thin films of Ag for coloration of the photocatalyst films, ◎ was found to be between 0.1 μm and 0.4 μm, ○ was found to be between 0.4 μm and 0.9 μm, and x was found for 1 μm.

As is clear from the above 7 experiments, the thickness of the photocatalyst thin film is 0.1 μm or more and 0.9 μm or less, preferably 0.1 μm or more and 0.4 μm or less. In addition, it was found that the photocatalyst film was fixed to the substrate through the glaze layer to improve the abrasion resistance.

In addition, the characteristics of the design are utilized, with the film thickness also varying. That is, in the range of 0.2 μm to 0.4 μm, a stripe pattern of an iridescent color is produced by the interference of visible light with the photocatalyst film, and a distinctive impression is given to the appearance. On the other hand, the iridescent pattern was not formed at 0.2 μm or less and at 0.4 μm or more and at 0.9 μm or less. The color of the substrate or the color, pattern or appearance associated with the combination of the same may be used as is.

Example 50

Coating TiO with average particle size of 0.01 μm on a tile substrate of 15cm square by spray coating₂The ammonia dispersion of the sol was calcined at 900 ℃ to form rutile TiO of 0.8 μm thickness₂A film. Then, the amount of the copper acetate aqueous solution (solution concentration: 0.2% (by weight), 0.5% (by weight), 1% (by weight)) applied was varied on the surface of the tile by sprayingThe copper acetate aqueous solution was applied, and then photoreduction was carried out (light source was a 20W BLB lamp, distance from the light source to the sample was 10cm, irradiation time was 10 seconds), to obtain a sample. The antibacterial properties of the obtained samples were evaluated. The residual aqueous solution after irradiation was recovered, and the Cu supporting amount was calculated from the difference between the initial copper amount and the recovered copper amount.

Fig. 59 shows the relationship between the Cu loading and the bacterial survival rate in light irradiation (L) and dark (D). The following fact can be understood from the figure.

First, the antibacterial property is improved by the support of Cu. When the amount of Cu carried is smaller in the light irradiation (L) than in the dark (D), the antibacterial property is high. This is because the rutile TiO recovers the photoactivity by supporting Cu at the time of light irradiation (L)₂The photocatalytic effect of the film is active. As is clear from the figure, 0.12. mu.g/cm was added²Above is ++, 0.3 mug/cm is added²This increases towards +++.

Since Cu itself is known to have an antibacterial action, it is known that the antibacterial activity is improved by increasing the amount of copper supported in the dark. At this time, the supporting amount was 0.7. mu.g/cm²Above, it is ++, and the carrying capacity is 1.2 mug/cm²When it is needed, it is raised to +++.

Therefore, it was 0.12. mu.g/cm in terms of + + level²Above, 0.7 mu g/cm²In the following, water according to +++The average was 0.3. mu.g/cm²Above, 1.2 mu g/cm²The following Cu-supporting amount, which has a good antibacterial property when irradiated with light (L), is considered to be Cu and rutile TiO²Special effects due to the combination of rutile TiO²A thin film is present. The Cu loading may be small. In this way, the amount of Cu carried can be reduced, and this is an important property particularly when such a composite member is used around water, and the amount of elution can be suppressed even when the composite member is used in an environment where copper can elute into water, for example, when the composite member is used on a sink surface in a washbasin or sanitary ceramics.

In the case of Cu, Cu is used₂The same effect is obtained with the form of O. This is because the surface at the time of photoreduction was detected as 1-valent Cu by ESCA, although Cu was detected₂Partially changed to Cu⁺But the effect of photoactivity recovery was observed.

On the other hand, the Cu supporting amount was set to 0.7. mu.g/cm²Above, preferably 1.2. mu.g/cm²As described above, the antibacterial activity is excellent in both the presence and absence of light irradiation.

Further, FIG. 60 shows the relationship between the Cu coating amount and the Cu supporting amount when the Cu concentration in the solution is 1 wt%, and it is understood from this figure that the Cu supporting amount is not increased even if the Cu coating amount is simply increased, and the Cu supporting amount is 0.7. mu.g/cm²As described above, the amount of Cu to be applied may be 0.2mg/cm ²Above, 2.7mg/cm²Hereinafter, the amount of Cu to be supported was 1.2. mu.g/cm²As described above, the amount of Cu to be applied may be 0.3mg/cm²Above, 2.4mg/cm²The following.

Example 51

Coating TiO with average particle size of 0.01 μm on a tile substrate of 15cm square by spray coating₂The ammonia dispersion of the sol was calcined at 900 ℃ to form rutile TiO of 0.8 μm thickness₂A film. Then, the surface of the tile was coated with a silver nitrate aqueous solution (solution concentration: 0.2% (by weight), 0.5% (by weight), 1% (by weight)) by changing the coating amount, and then subjected to photoreduction (light source: 20W BLB lamp, distance from the light source to the sample: 10cm, irradiation time)10 seconds) to obtain a sample. The antibacterial properties of the obtained samples were evaluated. The residual aqueous solution after irradiation was recovered, and the amount of Ag supported was calculated from the difference between the initial amount of silver and the recovered amount of silver.

FIG. 61 shows the relationship between the amount of Ag supported and the bacterial survival rates in the light irradiation (L) and dark (D). The following fact is clear from this figure.

First, unlike the case of Cu, the bacterial survival curves in the light irradiation (L) and dark (D) overlap. This is because the antimicrobial activity of Ag is far greater than that of Cu and the effect is produced with a very small amount of loading, and therefore, the difference between the necessary amounts of loading during light irradiation (L) and dark (D) is considered to fall within the experimental error range.

As is clear from the figure, the amount of Ag supported was set to 0.05. mu.g/cm²In the above-mentioned manner,preferably 0.1. mu.g/cm²As described above, the antibacterial activity is excellent in both the presence and absence of light irradiation.

FIG. 62 is a graph showing the color difference between the amount of silver loaded and the sample without silver loaded, and when the amount of silver loaded exceeds 1. mu.g/cm²The color difference becomes large sharply exceeding 2. Generally, the color difference is 2 or more, and the difference in color is significant. When silver is attached, the color changes from brown to black, which is not preferable because the appearance is unsightly. Therefore, it is desirable that the color difference is controlled to 2 or less, and for this reason, the amount of silver supported is 1. mu.g/cm²And (4) finishing. Further, the color difference was measured by a spectroscopic colorimeter (manufactured by Tokyo Denshoku Co., Ltd.).

However, in the above examples, in order to prevent as much as possible the reduction in the chemical bonding ability or the restoration of the activity of the active site of the photocatalyst caused by the coating of some molecular substance or dust with the surface treatment agent, it has been described that the active site of the fine particle having the photocatalytic activity is coated with fine particles of a metal such as silver, copper, platinum, palladium, gold, nickel, iron, cobalt, or zinc, but since such a metal is a nonferrous metal, if a large amount of such a metal is applied, a solid color is attached to the surface of the substrate, and the color, pattern, etc., of the substrate are impaired.

Therefore, a method of decoloring without impairing the color, pattern, etc. of the substrate while maintaining a high photocatalytic activity is described below.

As a basic method, a catalyst containing metal fine particles is produced by two processes of fixing metal fine particles on particles having photocatalytic activity, and reacting the metal fine particles with an aqueous solution or a gas to form a colorless or white salt on at least the surface of the metal fine particles.

The order in which the two processes are performed is different, but may be from where. That is, the fine metal particles may be fixed to the particles having photocatalytic activity, and then the fine metal particles may be reacted with an aqueous solution or a gas to form a colorless or white salt at least on the surfaces of the fine metal particles, or the fine metal particles may be reacted with an aqueous solution or a gas to form a colorless or white salt at least on the surfaces of the fine metal particles and then fixed to the particles having photocatalytic activity.

In this case, for example, a process of mixing the photocatalytic particles and the fine nonferrous metal particles, a process of applying the mixed liquid to the substrate, a process of fixing the mixture to the substrate by baking, and a process of reacting with a gas to form a colorless or white salt at least on the surface of the fine metal particles may be sequentially performed.

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

The non-ferrous metal fine particles are metal fine particles which have a small tendency to be plasmatized with silver, copper, platinum, palladium, gold, nickel, zirconium, cobalt, and zinc and are easily reduced by themselves.

When a colorless or white salt is formed by an aqueous reaction or when a catalyst containing metal fine particles is used in a liquid, the colorless or white salt formed may be hardly soluble or insoluble.

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

In the case of a catalyst containing metal fine particles prepared by fixing particles having a photocatalytic activity to a substrate in advance, the procedure of forming a particle layer having a photocatalytic activity on the substrate, the procedure of fixing nonferrous metal fine particles thereon, and the procedure of covering the nonferrous metal fine particles to form a colorless or white salt may be performed in this order.

The process of forming a colorless or white salt by coating the fine colored metal particles is carried out, for example, by a method of contacting the fine metal particles with a solution which reacts with the fine colored metal particles to form a colorless or white salt at least on the surfaces of the fine metal particles, or a method of contacting the fine metal particles with a reaction gas which reacts with the fine colored metal particles to form a colorless or white salt at least on the surfaces of the fine metal particles.

Among the salts of the fine colored metal particles, the white or colorless salt is preferably a sparingly soluble or insoluble salt. Therefore, the reaction in an aqueous solution can easily form a salt at least on the surface of the metal fine particles, and can be stably used in an environment where water is present.

Examples of the white or colorless salt in the above-mentioned fine colored metal salts include silver chloride, silver bromide, silver iodide, silver oxalate, silver thiosulfate, silver cyanide, silver thiocyanide, cuprous chloride, cuprous bromide, cuprous cyanide, cuprous thiocyanide, cuprous oxide, zinc phosphate, zinc oxalate, zinc cyanide, palladium cyanide, zinc sulfide, zinc carbonate, ferrous carbonate, and zinc oxide. Examples of the solution capable of forming the salt include a potassium chloride solution, a sodium chloride solution, an ammonium chloride solution, a ferrous chloride solution, and the like in the case of silver chloride, and potassium iodide solution, a sodium iodide solution, a ferrous iodide solution, hydrogen peroxide solution, ozone water, and the like in the case of silver iodide.

Further, if the reaction gas capable of forming the above-mentioned salt also contains anion elements of various salts, thenAnd can be widely used. For example, if the salt is an oxide such as zinc oxide or cuprous oxide, the salt is heated in air, oxygen, water vapor, or with O₃The oxidizing agent is reacted to oxidize the surface of the metal particles, thereby forming an oxide layer on the surface.

Specific examples are given below

Example 52

A titanium oxide sol having an average particle size of 0.01 μm was applied to the surface of a tile substrate having a square shape of 15cm, and then heat-treated at 900 ℃ to form a rutile titanium oxide film. The sample formed up to this stage was referred to as comparative sample 1.

Thereafter, an aqueous silver nitrate solution was applied by a spray method, and the film was irradiated with a 20W BLB lamp for 10 minutes to fix silver on the rutile type titanium oxide film. The amount of silver carried at this time was 1.2. mu.g/cm²And a brown color is presented. The sample formed up to this stage was referred to as comparative sample 2.

Thereafter, at 0.1cc/cm²The reaction was carried out by applying 0.1mol/L aqueous solution of potassium iodide to comparative sample 2. As a result, the surface of the sample turned yellow-white to turn white. It is considered that the silver iodide layer was formed. This sample was designated as example sample 1.

These samples were evaluated for color difference, photoactivity, odor resistance and antibacterial property.

The color difference was measured by a spectroscopic colorimeter (manufactured by Tokyo Denshoku Co., Ltd.). At this time, the standard sample was designated as comparative sample 1. The results are shown in FIG. 63. As a result, the color difference of comparative sample 2 was 3.5, whereas the color difference of example sample 1 was reduced to 1 by treating with the aqueous solution of potassium iodide, and the degree of color development was reduced.

The results of photoactivity and odor resistance are shown in FIG. 64, by comparing

samples

1 and 2, photoactivity recovery of sample 2 due to silver loading, △ pH and R₃₀In addition, example 1 and comparative example 2 are known to compare △ pH and R₃₀(L) is substantially the same value, and even when the decoloring treatment is applied, the resultantThe activity was not changed and the good characteristics were maintained.

Further, regarding the antibacterial property, the test was carried out using Escherichia coli W3110 strain. 0.15ml (2X 10) of a solution was dropped onto the outermost surface of a sample previously sterilized with 70% ethanol⁴CFU) was placed on a glass plate (100 × 100) and was closely attached to the outermost surface of the substrate to prepare a sample. The sample (L) irradiated with white light (3500 lux) for a predetermined period of time and the bacterial suspension holding the sample (D) under a light-shielded condition were wiped with sterilized gauze, and the number of viable bacteria was measured and evaluated by recovering the bacterial suspension in 10ml of physiological saline.

The results regarding antibacterial activity are shown in fig. 65. The comparative sample 1 does not carry silver, and therefore the antibacterial effect in the dark (D) is not observed. On the contrary, in example 1, although the surface of silver was changed to a compound by the decoloring treatment, the antibacterial effect in the dark (D) was observed. In addition, a stronger antibacterial effect was observed in (L) upon light irradiation, and not only the antibacterial effect of silver but also the photocatalytic activity recovery effect of the rutile titanium oxide film was observed.

Example 53

After coating a 15cm square shaped sanitary ceramic green body with glaze, baking at 1100-1200 ℃, then coating anatase type titanium oxide sol with the average particle size of 0.01 μm, baking at 900-1000 ℃, and fixing the rutile type titanium oxide film on the sanitary ceramic green body substrate.

Thereafter, an aqueous silver nitrate solution was applied thereto, and ultraviolet light was irradiated thereto to deposit silver on the titanium oxide thin film. Then, ferrous chloride aqueous solution was coated thereon, and the resultant was irradiated with ultraviolet rays to decolorize the pigment, whereby the color difference was reduced from 3 to 0.3. Further, the antibacterial activity was confirmed to be good when the sample was contacted with the light irradiation in the dark for 30 minutes, and the number of viable bacteria was 10% or less of the original number of bacteria.

Example 54

After coating a 15cm square shaped sanitary ceramic green body with glaze, baking at 1100-1200 ℃, coating anatase type titanium oxide sol with the average particle size of 0.01 μm, baking at 900-1000 ℃, and fixing the rutile type titanium oxide film on the sanitary ceramic green body substrate.

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

Example 55

After coating a 15cm square shaped green body of a sanitary ceramic, the green body was baked at 1100 ℃ and 1200 ℃ and coated with a mixture of an anatase-type titanium oxide sol having an average particle size of 0.01 μm dispersed in an aqueous nitric acid solution and an aqueous silver nitrate solution, followed by baking to fix a titanium oxide thin film on the green body of a sanitary ceramic. In this case, the brown color is developed when the composition is baked at 700 ℃ or lower, but the discoloration is caused when the composition is baked at 700 ℃ or higher. This may be explained because the silver surface reacts with components in the atmosphere. Further, the antibacterial property of the sample was measured on the anatase type titanium oxide film fixed on the green sanitary ware substrate after baking at 850 ℃, and it was confirmed that the living bacteria were 10% or less of the original number of bacteria when the sample was contacted with the sample both in light irradiation and dark for 3 hours, and good results were shown.

Example 56

After coating a 15cm square shaped sanitary ceramic green body with glaze, baking at 1100-1200 ℃, coating anatase type titanium oxide sol with the average grain diameter of 0.01 μm on the sanitary ceramic green body, baking at 900-1000 ℃, and fixing the rutile type titanium oxide film on the sanitary ceramic green body.

Then, a silver nitrate aqueous solution was applied thereon, and ultraviolet rays were irradiated thereto to deposit silver on the titanium oxide thin film. Then, hydrogen peroxide water was applied thereto to decolorize the film. Further, the antimicrobial activity was confirmed to be only 10% or less of the original number of viable bacteria by contacting the sample for 3 hours both in the light irradiation and in the dark, and good results were obtained.

Next, description will be made with respect to rutile type TiO₂Mixing the particles with tin oxide, to improve the compactness and adhesion of the photocatalyst film and to improve the activity.

The method of forming the photocatalyst thin film may be either of the following two methods.

One is to mix TiO in advance₂Sol and tin oxide sol, and a method of coating the sol and tin oxide sol on the surface of a substrate and baking the coated substrate.

TiO₂The mixing of the sol and the tin oxide sol is carried out in an alkaline aqueous solution. Both showed good dispersion because of the alkaline side from an electrochemical point of view. The alkaline aqueous solution includes ammonia and hydroxides of alkali metals or alkaline earth metals, but ammonia is particularly preferable because no metal contamination is generated after the heat treatment. Further, an organic dispersant, a phosphoric acid dispersant, a surface treatment agent, and a surfactant may be added to these dispersions.

As the coating method, there is a method of forming a coating film by spraying, dipping, roll coating, spin coating, CVD, electron beam evaporation, sputtering, or the like of the above-mentioned mixed solution, but any of them may be used, and other methods may be used. However, spray coating, dip coating, and roll coating have the advantage that a coating film can be formed at low cost without requiring special equipment as compared with CVD, electron beam deposition, sputtering, and the like.

After coating, the film may be dried before firing. The drying can be carried out at room temperature to about 100 ℃.

The calcination is carried out at a temperature sufficient to produce rutile. The temperature is 830 ℃ or higher at normal pressure in the coexistence with tin oxide.

Without the formation of TiO₂And solid solutions of tin oxide. To form TiO₂And of tin oxideThe solid solution needs to be maintained at a high temperature for a long time, and thus the production efficiency becomes low.

Another method is to form rutile TiO₂After the film is formed, a tin oxide sol is added thereto, followed by baking.

The method begins with the application of a Ti-containing starting material to a substrate. TiO is used as the starting material₂Sol, titanium alkoxide, sulfate of Ti, chloride solution of Ti, and the like. In the use of TiO₂In the case of sol, TiO₂Has an isoelectric point of pH6.5 and is substantially neutral, so that the coating is carried out using an aqueous solution in which an acid or a base is dispersedIs coated on the base material, and is easy to be uniformly coated. In the case where the substrate is a metal, the alkali dispersion is preferable from the viewpoint of corrosion resistance. In the case of ceramics, tiles, ceramics, etc., any of acid and alkali dispersions can be used. Examples of the acid include nitric acid, sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, and organic acids. The alkaline aqueous solution includes ammonia and hydroxides of alkali metals or alkaline earth metals, but ammonia is particularly preferable from the viewpoint that no metal contaminants are generated after the heat treatment. Further, an organic or phosphoric acid-based dispersant, a surface treatment agent, and a surfactant may be added to these dispersions. In addition, TiO as a starting material₂The average particle diameter of the sol may be 0.05 μm or less, preferably 0.01 μm or less. When the particle size is small, initial sintering occurs at a lower temperature, and therefore a photocatalyst thin film having excellent peel strength can be formed at a low temperature. The method for applying the dispersion to a substrate may be any of methods, such as spray coating, dip coating, roll coating, spin coating, CVD, electron beam deposition, and sputtering, and the method may be other methods. However, spray coating, dip coating, and roll coating have the advantage that a coating film can be formed at low cost without requiring special equipment as compared with CVD, electron beam deposition, sputtering, and the like. After coating, drying may be performed before firing. The drying can be carried out at room temperature to about 100 ℃.

The coated composite member is then fired. Calcination is carried out at a temperature at which rutile is formed. The temperature is above 900 ℃ at normal pressure.

Thereafter, the composite member solidified by cooling is coated with a starting material serving as a Sn source and fired. As a starting material of the Sn source, there is a tin oxide sol or the like. In the solution of tin oxideAn aqueous alkaline solution may be used in the glue. Since the tin oxide sol is stable electrochemically on the alkali side. The alkaline aqueous solution includes ammonia and hydroxides of alkali metals or alkaline earth metals, but ammonia is particularly preferable from the viewpoint that no metal contaminants are generated after the heat treatment. Further, an organic or phosphoric dispersant, a surface treatment agent, and a surfactant may be added to these dispersions. Is applied to a substrateThe method of (3) may be any of methods for forming a coating film by applying these dispersions by spraying, dipping, roll coating, spin coating, CVD, electron beam deposition, sputtering, or the like, or may be any other method. However, spray coating, dip coating, and roll coating have advantages over CVD, electron beam deposition, sputtering, and the like in that a coating film can be formed at low cost without requiring special equipment. After coating, drying may be performed before firing. Drying is preferably carried out at room temperature to about 100 ℃. The firing temperature may be a temperature at which the organic additive components are evaporated from the tin oxide. The temperature is above 300 ℃ at normal pressure. In addition, the formation of TiO is not necessary₂And solid solutions of tin oxide. To form TiO₂And tin oxide, the solid solution needs to be maintained at a high temperature for a long time, and thus the production efficiency becomes low.

Furthermore, rutile type TiO is formed on the surface of the substrate₂And tin oxide having a crystal grain size of 0.01 μm or less, and fixing Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu₂At least one metal of O.

These metals have an electron-capturing effect, and the rutile type TiO improves the electron-capturing effect₂And a tin oxide having a crystal grain size of 0.01 [ mu ] m or less.

In particular, Cu and Ag have antibacterial activity and can impart dark activity to antibacterial properties, and therefore, can maintain a certain level of antibacterial activity even without light irradiation. Fixing Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu₂The method for fixing at least one metal of O comprises applying an aqueous solution of at least one metal salt of these metals and fixing the metal salt by a photo-reduction method or a heat treatment method.

In the aqueous metal salt solution, the metal is dissolved substantially as a cation. Specific examples thereof 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.

The coating method of the metal salt aqueous solution includes a spray coating method and a dip coating method, but the spray coating method is more preferable because the amount of the metal salt aqueous solution used is small, the coating is uniform, the film thickness is easily controlled, and the metal salt aqueous solution is not attached to the back surface as required.

In the case of the photo-reduction method, the metal ions are reduced by irradiating the film with ultraviolet-containing light, and the film is made of rutile TiO₂And tin oxide having a crystal grain size of 0.01 μm or less, wherein Cu, Ag, Pt, Fe, Co, Ni, Pd, Cu are fixed to a thin film₂At least one metal of O.

The light source for irradiating the light containing ultraviolet rays may be a light source capable of irradiating the light containing ultraviolet rays, and specifically may be any of an ultraviolet lamp, a BLB lamp, a xenon lamp, a mercury lamp, a fluorescent lamp, and the like. In the method of irradiating ultraviolet-containing light, it is preferable to arrange the sample so that the light is perpendicularly contacted with the irradiation surface. Because the irradiation efficiency is optimal. It is desirable that the distance from the light source to the sample is 1cm to 30 cm. If the distance is too short, the entire sample surface cannot be irradiated with light with substantially uniform illuminance, and the metal species are likely to adhere unevenly, whereas if the distance is too long, the illuminance of the irradiated light becomes less quadratically proportional to the distance, and therefore it is difficult to firmly adhere the metal species.

In the heat treatment method, the metal is then fixed by heating to a sufficient temperature. The temperature is preferably 100 ℃ or higher. However, for example, when the treatment is carried out at a so-called high temperature of 800 ℃ or higher, the metal is oxidized, and therefore, in this case, the metal is limited to a metal which does not lose the electron capturing effect or does not lose the antibacterial property even if oxidized. That is, it should be limited to Ag and Cu. In the case of Ag or Cu, the electron capturing effect and antibacterial property are not lost even when the material is baked at high temperature, and therefore the following production methods are also possible. I.e. premixing TiO₂A method in which a sol and a tin oxide sol are applied to the surface of a substrate, and then an aqueous solution of a metal salt is applied thereto and then the resultant is baked. According to this method, the firing process can be completed at one time, and the productivity is improved and the production cost is reduced.

The following specific examples are given

Example 55

Adding 4-6 wt% of a knot to an aqueous ammonia solution adjusted to a pH of 11TiO with grain size of 0.01 mu m₂Sol to prepare suspension A. In a separate vessel, 10 wt% of a tin oxide sol having a crystal grain size of 0.0035 μm was added to an aqueous ammonia solution adjusted to pH11 to prepare suspension B. The suspension A and the suspension B were mixed in a predetermined ratio, and then applied by spraying onto a 15cm square tile substrate surface, dried, and then baked at 850 ℃ for 2 hours to obtain a sample. TiO in the resulting sample₂The crystalline form is the rutile form. Further, the lattice constant was measured by powder X-ray diffraction, and no solid solution of tin oxide in TiO was observed₂In the crystal lattice. The resulting samples were evaluated for photoactivity and abrasion resistance.

Regarding the photoactivity, the surface of the sample was dropped with an aqueous solution of potassium iodide, and then the dropped aqueous solution of potassium iodide was irradiated with ultraviolet rays for 30 minutes, and evaluated by the difference between the pH of the aqueous solution of potassium iodide before irradiation and the pH of the aqueous solution of potassium iodide after irradiation. That is, according to this method, when the photoactivity of the sample surface is increased, the following redox reaction proceeds more easily, and therefore the pH after irradiation is higher than the pH before irradiation.

And (3) oxidation reaction:

reduction reaction:

further, the abrasion resistance was evaluated by sliding friction with a plastic rubber and comparing the change in appearance, and the evaluation indexes ◎, ○, △ and x were the same as described above.

The change in abrasion resistance with respect to the weight ratio of tin oxide in the film is shown in fig. 66. the abrasion resistance shows good results with or without tin oxide, ◎ or ○.

In particular, when the tin oxide content exceeds 30%, ◎ is obtained because of the TiO content as the starting material₂The ratio of the crystal grain size of the sol (0.01 μm) to the crystal grain size of the tin oxide (0.0035 μm) is 2 or more, and the TiO is filled with fine tin oxide particles₂Gaps between particles, improved filling property, and filmAnd is more compact.

Fig. 67 shows the change in photoactivity with respect to the weight ratio of tin oxide in the thin film. For comparison, rutile TiO which exhibits excellent antibacterial and deodorant properties is also shown₂Sample with Cu supported thereon (in R)₃₀60%) △ pH and anatase TiO exhibiting very good antibacterial and deodorant properties₂Sample (in R)₃₀97%) △ pH. rutile TiO with tin oxide addition₂△ pH does not catch up with anatase TiO₂The weight ratio of tin oxide added is more than 10%, 80% or less, or 20% or more, 70% or less, in rutile TiO₂The △ pH of the Cu supported sample showed a greater value, and showed good photoactivity.

Even when tin oxide having an average particle size of 0.01 μm or more is added, the photocatalytic activity is not improved because the position of the conductive band is not sufficiently shifted by the fine particles of tin oxide, and the tin oxide particles do not have a band gap sufficient for generating active oxygen. In addition, if it is not more than 10%, sufficient photoactivity is not generated, which is caused by an insufficient amount ratio of tin oxide particles. On the other hand, the effect is weak at 80% or more because the probability that tin oxide in the photocatalyst layer exists adjacently becomes high, and it is estimated that the frequency of the grains growing up to 0.01 μm or more in the heat treatment becomes high.

Comparative example 56

Adding 4-6 wt% of TiO with crystal grain size of 0.01 μm into ammonia water solution with pH value of 11₂And (3) sol. Suspension a was made. In a separate vessel, 10% by weight of a tin oxide sol having a crystal grain size of 0.01 μm was added to an aqueous ammonia solution adjusted to a pH of 11 to prepare a suspension B. The suspension A and the suspension B were mixed in a predetermined ratio, and then applied by spraying onto a 15cm square tile substrate surface, dried, and then baked at 850 ℃ for 2 hours to obtain a sample. TiO in the resulting sample₂The crystal form of (2) is rutile type. Determination of TiO by powder X-ray diffraction₂Lattice constant, no tin oxide to TiO is seen₂Solid solution in crystal lattices. The samples were evaluated for photoactivity and abrasion resistance.

Fig. 68 shows the change in abrasion resistance with respect to the weight ratio of tin oxide in the thin film.Is not limited toThe result showed good wear resistance in the presence or absence of tin oxide, ○, which is considered to be that particles in the film were firmly bonded to each other by sintering at a so-called high temperature of 850 ℃₂The particle diameter ratio of the sol (crystal particle diameter 0.01 μm) to the tin oxide sol (crystal particle diameter 0.01 μm) was approximately equal.

The change in photoactivity relative to the weight ratio of tin oxide in the film is shown in fig. 69. For comparison, rutile TiO which exhibits excellent antibacterial and deodorant properties is also shown₂△ pH of Cu-loaded sample and anatase TiO exhibiting very good antibacterial and deodorant properties₂△ pH. rutile TiO with tin oxide addition for sample₂△ pH, this time far inferior to anatase TiO₂The △ pH of the sample was also much less than in the rutile TiO form₂△ pH of the Cu loaded sample.

Example 57

Adding 4-6 wt% of TiO with crystal grain size of 0.01 μm into ammonia water solution with pH value of 11₂Sol to prepare suspension A. In a separate vessel, 10 wt% of a tin oxide sol having a crystal grain size of 0.0035 μm was added to an aqueous ammonia solution adjusted to pH11 to prepare suspension B. And mixing the suspension A and the suspension B according to a given ratio, coating the mixture on the surface of a square ceramic tile substrate of 15cm by a spraying method, drying, and roasting at 850 ℃ for 2 hours to obtain the composite member. In the resulting composite component TiO₂The crystalline form is the rutile form. And the weight ratio of tin oxide in the film was 60%. In addition, TiO was measured by powder X-ray diffraction₂Lattice constant of (2), no tin oxide to TiO is seen₂Solid solution in crystal lattices. The composite member was further coated with a 5 wt% aqueous solution of copper acetate by spray coating, dried, and then subjected to photoreduction (light source: 20W BLB lamp, distance from light source to sample: 10cm, irradiation time: 1 minute) to obtain a sample. The obtained sample was evaluated for odor resistance R₃₀。

Here, R was determined by the following test₃₀. Methyl mercaptan was used as a decomposition gas, and the initial concentration of methyl sulfuric acid in the sample set was adjusted to 2ppm, the diameter was 26cm and the height was 21cmIn the cylindrical container of (1). A4W BLB fluorescent lamp was irradiated with light at a distance of 8cm from the sample for 30 minutes to calculate the reduction rate of the concentration of methyl mercaptan, and the odor resistance R at the time of irradiation with light was determined₃₀(L). Further, the reduction rate of the concentration of methyl mercaptan at the time of 30 minutes without light irradiation was calculated, and the odor resistance R in the dark was obtained₃₀(D) In that respect The results are shown in Table 26. For comparison, the samples (the weight ratio of tin oxide is 60%) prepared in example 55 and comparative example 56 were simultaneously tested. As is clear from Table 26, the following effects are exhibited by the addition of Cu. (watch 26)

Test specimen	R₃₀(L)	R₃₀(D)
Test specimen	R₃₀(L)	R₃₀(D)	Example 1	82	0
Example 2	97	92	Example 1	82	0
Example 2	97	92	Comparative example	32	0

(SnO₂Are all 60 percent by weight

As can be seen from Table 26, R is compared with the sample of example 53₃₀There was some improvement in (L). This is considered to be caused by the electron trapping effect of Cu. In addition, R is compared with example 53 and comparative example 54₃₀(D) The improvement is remarkable. This increase in dark activity can be explained by the catalytic effect of copper.

As is clear from the above description, in the member having a photocatalyst thin film formed on the surface of a substrate, the TiO in the photocatalyst thin film is used₂The roasting temperature at which the component becomes rutile type is treated, and sufficient compactness and TiO can be maintained₂Film strength. At this time, rutile type TiO is removed₂In addition, if tin oxide having a crystal grain size of 0.01 μm or less is present, the photocatalytic activity of the photocatalyst thin film can be improved.

At least one metal selected from Cu, Ag, Pt, Fe, Co, Ni and Pd is fixed on the photocatalyst film, and the photocatalytic activity can be further improved by utilizing the electron capture effect.

Industrial applicability

As described above, the present invention has antibacterial, antifouling, deodorizing and NO decomposition properties_xAnd the like, and is suitable for wall materials, tiles, glasses, mirrors, stone materials used as a circulation filter device, for example, artificial waterfall of a water circulation system or stone paving of water spray, sanitary ceramics such as toilet bowls and wash tables, hospital equipment for preventing hospital infection such as MRSA and the like, residential equipment, antifungal equipment, antiviral equipment, and the like.

Claims

1. A multifunctional material with photocatalytic function is characterized in that a photocatalyst layer with photocatalytic function is directly arranged on the surface of a base material, at least the surface part of the photocatalyst layer is exposed to the outside, and the surface part is formed by combining fine photocatalyst particles with each other by potential energy.

2. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is directly provided on the surface of a base material, at least the surface layer portion of the photocatalyst layer is exposed to the outside, and the surface layer portion is formed by solid-phase sintering and bonding of photocatalyst particles.

3. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is directly provided on the surface of a base material, at least the surface layer portion of the photocatalyst layer is exposed to the outside, and particles smaller than the gaps are filled in the gaps formed between photocatalyst particles constituting the surface layer portion.

4. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is directly provided on the surface of a base material, at least the surface layer portion of the photocatalyst layer is exposed to the outside, photocatalyst particles constituting the surface layer portion are bonded to each other with potential energy, and particles smaller than the gap are filled in the gap formed between the photocatalyst particles constituting at least the outermost layer portion.

5. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is directly provided on the surface of a base material, at least a surface portion of the photocatalyst layer is exposed to the outside, and at the same time, photocatalyst particles are bonded to each other with potential energy on the surface portion, and electron-capturing particles are immobilized on the surfaces of the photocatalyst particles.

6. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is directly provided on the surface of a base material, at least the surface layer portion of the photocatalyst layer is exposed to the outside, and the surface layer portion is constituted by combining photocatalyst particles by solid-phase sintering, and that electron-trapping particles are fixed on the surface of the photocatalyst particles.

7. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided directly on the surface of a base material, at least a surface layer portion of the photocatalyst layer is exposed to the outside, particles smaller than the gap are filled in the gap formed between photocatalyst particles constituting the surface layer portion, and electron-trapping particles are fixed on the surface of the photocatalyst particles or on the surface of small particles filled in the gap.

8. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is directly provided on the surface of a base material, at least the surface layer portion of the photocatalyst layer is exposed to the outside, photocatalyst particles constituting the surface layer portion are bonded to each other with potential energy, particles smaller than the gap are filled in at least the gap formed between the photocatalyst particles constituting the outermost layer portion, and electron-capturing particles are fixed on the surface of the photocatalyst particles or the surface of small particles filled in the gap.

9. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside while the lower layer portion is buried in the adhesive layer, and the surface layer portion is constituted by fine photocatalyst particles bonded to each other with potential energy.

10. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside while the lower layer portion is embedded in the adhesive layer, and the surface layer portion is constituted by photocatalyst particles bonded by solid-phase sintering.

11. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside while the lower layer portion is embedded in the adhesive layer, and particles smaller than the gaps are filled in the gaps formed between photocatalyst particles constituting the surface layer portion.

12. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside while the lower layer portion is embedded in the adhesive layer, and photocatalyst particles constituting the surface layer portion are bonded to each other with potential energy, and particles smaller than the gap are filled in at least the gap formed between the photocatalyst particles constituting the outermost layer.

13. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material through an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside, the lower layer portion is embedded in the adhesive layer, and fine photocatalyst particles are bonded to each other with potential energy on the surface layer portion, and electron trapping particles are fixed on the surfaces of the photocatalyst particles.

14. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer of the photocatalyst layer is partially exposed to the outside, the lower layer is partially embedded in the adhesive layer, the surface layer is composed of photocatalyst particles bonded by solid-phase sintering, and electron trapping particles are fixed to the surface of the photocatalyst particles.

15. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside, while the lower layer portion is embedded in the adhesive layer, and particles smaller than the gaps are filled in the gaps formed between the photocatalyst particles constituting the surface layer portion, and the electron trapping particles are fixed on the surfaces of the photocatalyst particles or on the surfaces of the small particles filled in the gaps.

16. A multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer having a photocatalytic function is provided on the surface of a base material via an adhesive layer, the surface layer portion of the photocatalyst layer is exposed to the outside while the lower layer portion is embedded in the adhesive layer, and photocatalyst particles constituting the surface layer portion are bonded to each other with potential energy, and particles smaller than the gap are filled in at least the gap formed between the photocatalyst particles constituting the outermost layer portion, and electron trapping particles are fixed on the surface of the photocatalyst particles or on the surface of the small particles filled in the gap.

17. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the photocatalyst particles constituting the photocatalyst layer are crystalline.

18. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the photocatalyst particles constituting the photocatalyst layer are anatase type TiO₂。

19. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the photocatalyst particles constituting the photocatalyst layer are rutile type TiO₂。

20. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the surface layer portion porosity of the photocatalyst layer is 20% or less.

21. The multifunctional material having a photocatalytic function according to claim 19, characterized in that the maximum width of the pores in the surface layer portion of said photocatalyst layer is 0.04 μm or less.

22. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the surface layer portion porosity of the photocatalyst layer is 10% or more and 40% or less.

23. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the particle diameter of particles constituting the photocatalyst layer is 0.1 μm or less.

24. The multifunctional material having a photocatalytic function according to any one of claims 1 to 16, characterized in that the particle diameter of the particles constituting the photocatalyst layer is 0.1 μm or more, the thickness of the photocatalyst layer is 0.5 μm or more, and necking portions are formed between the particles constituting the photocatalyst layer.

25. The multifunctional material having a photocatalytic function according to claim 3, 4, 7, 8, 11, 12, 15 or 16, wherein the surface layer portion of said photocatalyst layer has a porosity of 10% or more and 40% or less, and particles having a particle diameter of 0.1 μm or less are carried in the pores.

26. The multifunctional material having a photocatalytic function according to any one of claims 9 to 16, characterized in that the binder layer formed on the surface of said base material is an amorphous layer, and the amorphous adhesive layer and the photocatalyst layer have therebetween an intermediate layer in which the concentrations of both components are continuously changed.

27. The multifunctional material having a photocatalytic function according to claim 26, characterized in that the thickness of said intermediate layer is made greater than 1/3 times the thickness of the photocatalyst layer.

28. The multifunctional material having a photocatalytic function according to any one of claims 9 to 16, characterized in that the base material is composed of a low-melting-point material, and the adhesive layer formed on the surface of the low-melting-point base material is composed of a material having a higher melting point than that of the base material.

29. The multifunctional material having a photocatalytic function according to claim 28, characterized in that said photocatalyst layer is formed using an alkoxide compound as a raw material, and said low-melting-point substrate has a softening point higher than a crystallization temperature of the alkoxide compound, and the softening point of said intermediate layer is equal to or higher than the crystallization temperature of the alkoxide compound.

30. The multifunctional material having a photocatalytic function according to claim 3, 4, 7, 8, 11, 12, 15 or 16, characterized in that the particle diameter of particles filled in gaps formed between said photocatalyst particles is 0.01 μm or less.

31. The multifunctional material with photocatalytic function according to claim 5, 6, 7, 8, 13, 14, 15 or 16, characterized in that said electron trapping particles are Cu, Ag, Zn, Fe, Co, Ni, Pd, Cu₂O, Pt.

32. The multifunctional material having a photocatalytic function according to claim 3, 4, 7, 8, 11, 12, 15 or 16, characterized in that the porosity of the surface layer portion of said photocatalyst layer is 10% or more.

33. The multifunctional material having a photocatalytic function according to claim 3, 4, 7, 8, 11, 12, 15 or 16, wherein the porosity of the surface layer portion of said photocatalyst layer is 10% or more, and Cu, Ag, Zn, Fe, Co, Ni, Pd, Cu are fixed to the surface layer portion of said photocatalyst layer₂O, PtA metal.

34. The multifunctional material having photocatalytic function according to any one of claims 1 to 8, characterized in that said base material is composed of a thermoplastic material such as glaze, inorganic glass, thermoplastic resin, soft solder, etc., and is formed into a sheet shape.

35. The multifunctional material having photocatalytic function according to any one of claims 9 to 16, characterized in that the adhesive layer is composed of a thermoplastic material such as glaze, inorganic glass, thermoplastic resin, soft solder or the like.

36. The multifunctional material having a photocatalytic function according to claim 3, 4, 7, 8, 11, 12, 15 or 16, characterized in that the average particle diameter of particles filled in gaps formed between said photocatalyst particles is 4/5 or less of the average particle diameter of the photocatalyst particles.

37. The multifunctional material having a photocatalytic function according to claim 36, wherein the particles filled in the gaps between the photocatalyst particles are in a molar ratio of 10% or more and 60% or less with respect to the total amount of the photocatalyst particles and the filler particles.

38. The multifunctional material having a photocatalytic function according to claim 36, wherein the vapor pressure of the substance constituting the particles filled in the gaps of said photocatalyst particles is higher than that of the substance constituting the photocatalyst particles, and the particles filled in the gaps of the photocatalyst particles are aggregated in the constricted parts between the photocatalyst particles.

39. The multifunctional material having a photocatalytic function according to claim 38, characterized in that the particles filled in the gaps of said photocatalyst particles are tin oxide.

40. The multifunctional material having a photocatalytic function according to claim 36 or 37, characterized in that the particles filled in the gaps of the photocatalyst particles contain Ag, Ag₂O、Cu、Cu₂At least one of O, Zn, Fe, Pt, Co, Pd and Ni。

41. The multifunctional material with photocatalytic function according to claim 30, characterized in thatIn that the photocatalyst particles are rutile TiO₂The crystal grain size of the tin oxide particles filled in the gaps of the photocatalyst particles is 0.01 μm or less.

42. The multifunctional material with photocatalytic function according to claim 30, characterized in that the photocatalyst particles are rutile type TiO₂The crystal grain diameter of the tin oxide particles filled in the gaps of the photocatalyst particles is 0.01 μm or less, and further Cu, Ag, Fe, Co, Pt, Ni, Pd, Cu are provided on the photocatalyst layer₂At least one of O.

43. The multifunctional material with photocatalytic function according to claim 30, characterized in that the weight ratio of the tin oxide is 10% or more and 80% or less.

44. The multifunctional material having a photocatalytic function according to any one of claims 37 to 39, characterized in that the particles filled in the gaps of the photocatalyst particles have a photocatalytic activity.

45. The multifunctional material having a photocatalytic function according to claim 2, 6, 10 or 14, characterized in that the photocatalyst particles bonded by solid phase sintering are anatase-type titanium oxide particles, the intervals of the titanium oxide particles are approximately equal before and after sintering, and a substance having a vapor pressure higher than that of titanium oxide is condensed in the constricted parts between the titanium oxide particles.

46. The multifunctional material with photocatalytic function according to claim 5, 6, 7, 8, 13, 14, 15 or 16, characterized in that said photocatalyst layer is made of rutile TiO₂A film, the electron-trapping particles are Cu, Ag, Fe, Co, Pt, Ni, Pd, Cu₂At least one of O.

47. The multifunctional material with photocatalytic function according to claim 46, characterized in that said rutile type TiO₂The film is a porous body having a porosity of 10% or more.

48. The multifunctional material with photocatalytic function according to claim 46, characterized in that said rutile type TiO₂The thickness of the film is 0.1 to 0.9 μm.

49. The multifunctional material with photocatalytic function as in claim 46, characterized by the fact that said Cu, Ag, Fe, Co, Pt, Ni, Pd, Cu₂In OAt least one of TiO 2 having a particle diameter ratio₂The pore diameter of the film is small.

50. The multifunctional material having a photocatalytic function according to any one of claims 46 to 49, characterized by being fixed to said TiO₂The material on the film is Cu or Cu₂At least one of O, TiO per unit area₂The fixed amount of the substance of the film was 0.12. mu.g/cm²Above, 1.2 mu g/cm²The following.

51. The multifunctional material having a photocatalytic function according to any one of claims 46 to 49, characterized by being fixed to said TiO₂The material on the film is Cu or Cu₂At least one of O, TiO per unit area₂The substance immobilization amount of the film was 0.7. mu.g/cm²The above.

52. The multifunctional material having a photocatalytic function according to any one of claims 46 to 49, characterized by being fixed to said TiO₂The metal on the film being Ag per unit area of TiO₂The fixed amount of Ag in the film was 0.05. mu.g/cm²Above, 1 mu g/cm²The following.

53. The multifunctional material with photocatalytic function according to any one of claims 1 to 52, characterized in that the multifunctional material is a tile, stone used as a paving for artificial waterfalls and water sprays in a water circulation manner.

54. A process for producing a multifunctional material having a photocatalytic function, characterized by forming a photocatalyst layer on the surface of a substrate, applying a metal alkoxide or an organic metal salt to the surface of the photocatalyst layer, and then subjecting the resultant to a drying heat treatment to fill the gaps formed between the photocatalyst particles with particles smaller than the gaps.

55. A process for producing a multifunctional material having a photocatalytic function, characterized by comprising forming a photocatalyst layer on the surface of a substrate, applying a metal alkoxide or an organic metal salt to the surface of the photocatalyst layer, drying and heat-treating the resulting coating to fill the spaces formed between the photocatalyst particles with particles smaller than the spaces, and applying a coating containing Cu, Ag, Zn, Fe, Co, Ni, Pd and Cu₂O, Pt, and precipitating and fixing the metal particles by photo-reduction.

56. A method for producing a multifunctional material having a photocatalytic function, characterized by forming a photocatalyst layer comprising photocatalyst particles on a thermoplastic base material, softening the thermoplastic base material to embed a part of the lower layer of the photocatalyst layer in the thermoplastic base material, and then solidifying the resultant.

57. A method for producing a multifunctional material having a photocatalytic function, wherein a space between photocatalyst particles is filled with particles having a smaller particle diameter than the space, and the photocatalyst particles are bonded to each other to form the multifunctional material having the photocatalytic function, characterized in that a mixture obtained by mixing photocatalyst particles and particles having a smaller particle diameter in a sol, precursor or suspension state is applied to a thermoplastic base material to form a photocatalyst layer, and thereafter the thermoplastic base material is softened to embed a part of the lower layer of the photocatalyst layer in the thermoplastic base material, followed by solidification.

58. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles with metal particles having a particle diameter smaller than that of the gaps, and bonding the photocatalyst particles to each other to form a multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer comprising photocatalyst particles is formed on a thermoplastic base material, the thermoplastic base material is softened to embed a part of the lower layer of the photocatalyst layer in the thermoplastic base material, the thermoplastic base material is then solidified, a solution containing the metal particles having a small particle diameter is applied onto the photocatalyst layer, and heat treatment is carried out to fix the metal particles having a small particle diameter to the photocatalyst particles.

59. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles with metal particles having a smaller particle diameter than the gaps, and bonding the photocatalyst particles to each other to form a multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer comprising photocatalyst particles is formed on a thermoplastic substrate, the thermoplastic substrate is softened to embed a part of the lower layer of the photocatalyst layer in the thermoplastic substrate, the thermoplastic substrate is then cured, a solution containing ions of the metal particles having a smaller particle diameter is applied onto the photocatalyst layer, and then ultraviolet-containing light is irradiated to reduce the metal ions and fix the metal ions to the photocatalyst particles.

60. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles with metal particles having a smaller particle size than the gaps, and bonding the photocatalyst particles to each other to form a multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer comprising photocatalyst particles is formed on a thermoplastic substrate, 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, thereby fixing the metal ions to the photocatalyst particles, and the thermoplastic substrate is softened to embed a part of the lower layer of the photocatalyst layer in the thermoplastic substrate, and then the thermoplastic substrate is cured.

61. The method for producing a multifunctional material having a photocatalytic function according to claim 59 or 60, wherein at least one of metal species of a solution containing ions of metal particles is Cu, said metal particles are filled in gaps of photocatalyst particles, and the Cu supporting amount is 0.7 μ g/cm²Above, 10 mu g/cm²The following.

62. The method for producing a multifunctional material having a photocatalytic function according to claim 59 or 60, wherein at least one of metal species of a solution containing ions of metal particles is Ag, said metal particles are filled in gaps of said photocatalyst particles, and the amount of Ag carried is 0.05 μ g/cm²Above, 1. mu.g/cm²The following.

63. The method for producing a multifunctional material having a photocatalytic function according to claim 59 or 60, wherein the photocatalyst layer obtained by applying a solution containing an ion of said metal particle is dried before said ultraviolet-containing light is irradiated to reduce the metal ion and fixed on the photocatalyst particle.

64. The method for producing a multifunctional material having a photocatalytic function according to claim 63, wherein the solvent of the solution containing the ion of said metal particle is ethanol.

65. A method for producing a multifunctional material having a photocatalytic function according to any one of claims 56 to 64, characterized in that in order to form a photocatalyst layer on a thermoplastic substrate, a sol, precursor or suspension of photocatalyst particles is sprayed so that the temperature of the thermoplastic substrate becomes 20 ℃ or higher and 80 ℃ or lower.

66. The method for producing a multifunctional material having a photocatalytic function according to any one of claims 56 to 65, characterized in that as a process prior to the process of coating photocatalyst particles on a thermoplastic substrate in the production method, there is a dispersion process of using only a component having a vaporization temperature lower than a heat treatment temperature for softening the thermoplastic substrate in a sol which should become the photocatalyst particles in the dispersion process or in a dispersant for dispersing a precursor in a solution.

67. The method for producing a multifunctional material having a photocatalytic function according to any one of claims 56 to 65, characterized in that the production method utilizes a hydrothermal method, a sulfuric acid method for preparing a titania sol which should form photocatalyst particles, and for the titania sol, metal fine particles are fixed on the surfaces of the titania sol particles before adding a surface treatment agent such as a dispersant, a surfactant, etc.

68. A method for producing a multifunctional material having a photocatalytic function, characterized in that an adhesive layer made of a thermoplastic material is formed on the surface of a base material, a photocatalyst layer made of photocatalyst particles is formed on the adhesive layer, and thereafter the adhesive layer is softened to embed a part of the lower layer of the photocatalyst layer in the adhesive layer, followed by curing.

69. A process for producing a multifunctional material having a photocatalytic function, characterized by comprising forming a photocatalyst layer comprising photocatalyst particles on a sheet-like adhesive layer comprising a thermoplastic material, placing or sticking the sheet-like adhesive layer on the surface of a substrate, softening the adhesive layer to embed a part of the lower layer of the photocatalyst layer in the adhesive layer, and then curing the adhesive layer.

70. A process for producing a multifunctional material having a photocatalytic function, characterized by comprising forming an adhesive layer on the surface of a base material, forming a photocatalyst layer on the adhesive layer so that a part of the lower layer is embedded therein, and irradiating the resultant substrate with a light beam containing 1.7mW/cm²Light having a wavelength of 390nm or less causes the surface treatment agent attached to the surface of the photocatalyst to be preferentially decomposedGasifying to make lightThe catalyst particles are exposed to the outside.

71. The method for producing a multifunctional material having a photocatalytic function according to claim 70, wherein said adhesive layer is composed of a thermoplastic material having a softening temperature of 300 ℃ or lower, said adhesive layer is applied to a substrate, photocatalyst particles are further applied thereon, and then heat treatment is performed at a temperature lower than the softening temperature of the substrate and higher than the softening temperature of the adhesive layer, whereby the adhesive layer is softened and a part of the lower layer of the photocatalyst layer is embedded in the adhesive layer to form the photocatalyst layer.

72. The multifunctional material having a photocatalytic function according to claim 70, characterized in that said adhesive layer is composed of a thermosetting material, said adhesive layer is mixed with a curing agent, coated on a substrate, tackified by heat treatment or setting, coated with photocatalyst particles so that a part of the lower layer of the photocatalyst layer is embedded in the adhesive layer, and then cured by heat treatment.

73. A process for producing a multifunctional material having a photocatalytic function, characterized in that a layer mainly composed of photocatalyst particles and a thermosetting resin is formed on a base material, and then irradiated with a radiation beam containing 1.7mW/cm²The light having a wavelength of 390nm or less causes the thermosetting resin on the photocatalyst particles to be preferentially decomposed and gasified, thereby exposing the photocatalyst particles to the outside.

74. A process for producing a multifunctional material having a photocatalytic function, characterized in that a layer mainly composed of photocatalyst particles and a thermosetting resin is formed on the surface of a base material through a thermosetting resin layer or a photocurable resin, and then irradiated with a light beam having a concentration of 1.7mW/cm²The light having a wavelength of 390nm or less causes the thermosetting resin on the photocatalyst particles to be preferentially decomposed and gasified, thereby exposing the photocatalyst particles to the outside.

75. The method for producing a multifunctional material having a photocatalytic function according to claim 73 or 74, wherein the thermosetting resin in the layer composed of said photocatalyst particles and thermosetting resin is composed of at least one of a silicone resin and a fluororesin.

76. The method for producing a multifunctional material having a photocatalytic function according to any one of claims 70 to 74, wherein a gap is formed in the surface of the multifunctional material having a photocatalytic function, and the gap is filled with particles smaller than the gap.

77. A method for producing a multifunctional material having a photocatalytic function, wherein a space between photocatalyst particles bonded to each other is filled with particles having a smaller particle diameter than the space to form a multifunctional material having a photocatalytic function, characterized in that a binder layer made of a thermoplastic material is formed on the surface of a base material, and then a mixture obtained by mixing the photocatalyst particles and the small-particle-diameter particles in the form of a sol, a precursor or a suspension is applied onto the binder layer to form a photocatalyst layer, and thereafter the binder layer is softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, followed by curing.

78. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a smaller particle diameter than the gaps to form a multifunctional material having a photocatalytic function, characterized in that a sheet-like adhesive layer comprising a thermoplastic material is coated with a mixture obtained by mixing the photocatalyst particles and the particles having a smaller particle diameter in the form of a sol, a precursor or a suspension to form a photocatalyst layer, the sheet-like adhesive layer having the photocatalyst layer formed thereon is placed on or stuck to the surface of a substrate, and thereafter the adhesive layer is softened to embed a part of the lower layer of the photocatalyst layer in the adhesive layer and then cured.

79. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a particle diameter smaller than that of the gaps to form the multifunctional material having a photocatalytic function, characterized in that a binder layer comprising a thermoplastic material is formed on a substrate, a photocatalyst layer comprising photocatalyst particles is formed on the binder layer, the binder layer is softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, the binder layer is then cured, a solution containing the small-particle-diameter particles is applied on the photocatalyst layer, and heat treatment is carried out to fix the small-particle-diameter particles to the photocatalyst particles.

80. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a particle diameter smaller than that of the gaps to thereby form a multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer comprising photocatalyst particles is formed on a sheet-like adhesive layer comprising a thermoplastic material, the sheet-like adhesive layer having the photocatalyst layer formed thereon is placed on or stuck to the surface of a substrate, the adhesive layer is softened to embed a part of the lower layer of the photocatalyst layer in the adhesive layer, the adhesive layer is then cured, a solution containing the small-particle-diameter particles is applied onto the photocatalyst layer, and heat treatment is carried out to fix the small-particle-diameter particles to the photocatalyst particles.

81. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a smaller particle diameter than the gaps to form a multifunctional material having a photocatalytic function, characterized in that a binder layer comprising a thermoplastic material is formed on the surface of a substrate, a photocatalyst layer comprising photocatalyst particles is formed on the binder layer, the binder layer is softened to embed a part of the lower layer of the photocatalyst layer in the binder layer, the binder layer is then cured, a solution containing ions of the metal particles having a small particle diameter is applied onto the photocatalyst layer, and then light containing ultraviolet rays is irradiated to reduce the metal ions and fix the metal ions to the photocatalyst particles.

82. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a smaller particle diameter than the gaps to form a multifunctional material having a photocatalytic function, characterized in that a photocatalyst layer comprising photocatalyst particles is formed on a sheet-like adhesive layer comprising a thermoplastic material, the sheet-like adhesive layer having the photocatalyst layer formed thereon is placed on or stuck to the surface of a substrate, the adhesive layer is softened to embed a part of the lower layer of the photocatalyst layer in the adhesive layer, the adhesive layer is cured, a solution containing ions of the metal particles having a small particle diameter is applied onto the photocatalyst layer, and then light containing ultraviolet rays is irradiated to reduce the metal ions and fix the metal ions to the photocatalyst particles.

83. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a smaller particle diameter than the gaps to form a multifunctional material having a photocatalytic function, characterized in that a binder layer comprising a thermoplastic material is formed on the surface of a substrate, a photocatalyst layer comprising photocatalyst layer particles is formed on the binder layer, a solution containing ions of the metal particles having a small particle diameter is applied onto the photocatalyst layer, and then ultraviolet-containing light is irradiated to reduce the metal ions and fix them on the photocatalyst particles, and 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 cured.

84. A process for producing a multifunctional material having a photocatalytic function, which comprises filling gaps between photocatalyst particles bonded to each other with particles having a particle diameter smaller than that of the gaps, characterized in that a photocatalyst layer comprising photocatalyst particles is formed on a sheet-like binder layer comprising a thermoplastic material, a solution containing ions of the metal particles having a small particle diameter is applied on the photocatalyst layer, then ultraviolet-containing light is irradiated to reduce the metal ions and fix the metal ions on the photocatalyst particles, the sheet-like binder layer having the photocatalyst layer formed thereon is placed on or stuck to the surface of a base material, the binder layer is softened, and a part of the lower layer of the photocatalyst layer is embedded in the binder layer, and the binder layer is then cured.

85. The method for producing a multifunctional material having a photocatalytic function according to claim 83 or 84, wherein said photocatalyst particles are ZnO, and the metal particles filled in the gaps of the photocatalyst particles are Ag or Ag₂O。

86. A method for producing a multifunctional material having a photocatalytic function according to any one of claims 77 to 85, characterized by bringing a solution containing a salt forming an insoluble colorless or white salt between metal ions filled in gaps of said photocatalyst particles into contact with a photocatalyst layer and thereafter irradiating a light containing ultraviolet rays.

87. Method for producing a multifunctional material with photocatalytic function according to any one of claims 68 to 85, characterized in that the photocatalyst particles are TiO₂The heat treatment temperature for softening the adhesive layer is 800 ℃ to 1000 ℃.

88. The method of making a multifunctional material with photocatalytic function as in claim 86, characterized in that said photocatalyst particles are TiO₂The metal particles filled in the gaps of the photocatalyst particles are Ag, and the solution containing salts forming insoluble colorless or white salts among the metal ions is KI, KCl, FeCl₃And the like aqueous halide solutions.

89. The method for producing a multifunctional material having a photocatalytic function according to any one of claims 68 to 88, characterized in that said adhesive layer is selected from adhesives having a softening temperature lower than that of the base material, and the heat treatment is carried out at an atmospheric temperature higher than the softening temperature of the adhesive layer by 20 ℃ to 320 ℃ and lower than that of the base material.

90. The method for producing a multifunctional material having a photocatalytic function according to any one of claims 68 to 89, characterized in that as a process before coating photocatalyst particles on the binder layer, there is provided a dispersion process in which only a component that vaporizes at a temperature lower than a heat treatment temperature for softening the binder layer is used in a dispersing agent for dispersing a sol or a precursor or a suspension in a solution, in which the photocatalyst particles should be formed in the dispersion process.

91. The method for producing a multifunctional material having a photocatalytic function according to any one of claims 68 to 90, wherein 0. ltoreq. δ t- δ b. ltoreq.3.0 with the specific gravity of said photocatalyst particles as δ t and the specific gravity of said binder layer as δ b.

92. A process for producing a multifunctional material having a photocatalytic function, characterized by comprising forming an adhesive layer on the surface of a substrate, forming a photocatalyst layer in which the surface layer is partially exposed from the adhesive layer and the lower layer is partially embedded in the adhesive layer, coating the surface of the photocatalyst layer with a metal alkoxide or an organic metal salt, and drying the coating to fill the gaps formed between the photocatalyst particles with particles smaller than the gaps.

93. A process for producing a multifunctional material having a photocatalytic function, characterized by comprising forming a binder layer on the surface of a substrate, forming a photocatalyst layer in which the surface layer is partially exposed from the binder layer and the lower layer is partially embedded in the binder layer, coating the surface of the photocatalyst layer with a metal alkoxide or an organic metal salt, followed by heat treatment to fill the gaps formed between the photocatalyst particles with particles smaller than the gaps, coating an aqueous solution containing at least one metal ion selected from Ni, Pd and Pt, and precipitating and fixing the metal particles by photoreduction.

94. The method for producing a multifunctional material having a photocatalytic function according to claim 54, 55, 92 or 93, wherein the metal alkoxide applied to the surface of said photocatalyst layer is a titanium alkoxide, and the amount of the titanium alkoxide applied is converted to TiO₂Is 10. mu.g/cm²Above, 100. mu.g/cm²The following.

95. The method for producing a multifunctional material having a photocatalytic function according to claim 54, 55, 92 or 93, wherein the metal alkoxide coated on the surface of said photocatalyst layer is a titanium alkoxide having a heat treatment temperature of 400 ℃ or more and 800 ℃ or less.

96. The method for producing a multifunctional material having a photocatalytic function according to claim 54, 55, 92 or 93, wherein the metal alkoxide applied to the surface of said photocatalyst layer is a titanium alkoxide, and the amount of hydrochloric acid is 1% by weight or more and 10% by weight or less based on the titanium alkoxide in the coating liquid.

97. A process for producing a multifunctional material having a photocatalytic function, characterized by mixing a titania sol and a sol of a substance having a vapor pressure higher than that of titania, applying the mixed sol to a substrate, and sintering the substrate at a temperature lower than the temperature at which the substrate is converted to the rutile phase.

98. A process for preparing multifunctional material with photocatalytic function features that the particles with photocatalytic activity and non-ferrous metal particles are fixed to the surface of substrate, and the metallic particles are made to react with solution or gas to form colorless or white salt on the surface of metallic particles.

99. The method for producing a multifunctional material having a photocatalytic function as claimed in claim 98, wherein the liquid reacting with said metal particles is a halide solution, hydrogen peroxide water, ozone water.

100. The method for producing a multifunctional material having a photocatalytic function as set forth in claim 98, wherein the gas reacting with said metal particles is oxygen or ozone.

101. The method for producing a multifunctional material having a photocatalytic function as set forth in claim 98, wherein the liquid or gas reacting with said metal particles is an oxidizing agent.

102. A process for producing a multifunctional material having a photocatalytic function, characterized by forming rutile type TiO on the surface of a substrate₂Coating an aqueous solution of at least one metal salt selected from Ni, Pd and Pt or an ethanol solution of the metal salt on the thin film, and irradiating the film with ultraviolet-containing light to reduce metal ions and fix the metal on rutile TiO₂On the film.

103. The method for producing a multifunctional material having a photocatalytic function as set forth in claim 102, wherein said rutile type TiO₂The film is a porous body having a porosity of 10% or more.

104. The method for producing a multifunctional material having a photocatalytic function as set forth in claim 102, wherein the reduction of metal ions by irradiating said ultraviolet-containing light is carried out after the applied aqueous solution of metal salt or the ethanol solution of metal salt is dried.

105. The method for producing a multifunctional material having a photocatalytic function as set forth in claim 102, wherein said rutile type TiO is formed on the surface of the substrate through the adhesive layer₂A film.

106. The method for producing a multifunctional material having a photocatalytic function as set forth in claim 105, wherein said rutile type TiO is made₂The thickness of the film is 0.1 μm to 0.9. mu.m.

107. Photo-catalysisA process for preparing multifunctional functionalized material features that the rutile-type TiO is formed on the surface of substrate₂A thin film, applying a Cu salt aqueous solution on the thin film, irradiating with ultraviolet-containing light to reduce Cu ions and fix the Cu metal on the rutile TiO₂The fixed amount on the film was 1.2. mu.g/cm²-10μg/cm²。

108. A process for producing a multifunctional material having a photocatalytic function, characterized by forming rutile type TiO on the surface of a substrate₂A film, applying an Ag salt aqueous solution on the film, irradiating the film with ultraviolet-containing light to reduce Ag ions and fix the Ag metal on the rutile TiO₂The fixed amount on the film was 0.1. mu.g/cm²-1μg/cm²。