JP2012035151A - Method for manufacturing photocatalyst structure, and photocatalyst functional product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a photocatalyst structure having excellent adhesiveness in a precoat layer on the base material and a photocatalytic layer and exhibiting high photocatalytic activity.SOLUTION: The method for manufacturing a photocatalyst structure includes steps of: (a) applying precoating liquid which contains a metal alkoxide compound on a base material to form a precoat layer, and (b) applying a photocatalytic coating liquid which contains a photocatalyst particle on the precoat layer before the hydrolysis reaction or the polycondensation reaction of the metal alkoxide compound is completed to form the photocatalytic layer.

Description

  The present invention relates to a method for producing a photocatalyst structure and a photocatalytic functional product having the photocatalyst structure.

  When a semiconductor is irradiated with light having energy greater than or equal to the band gap, electrons in the valence band are excited to the conduction band and holes are generated in the valence band. The holes generated in this manner have a strong oxidizing power, and the excited electrons have a strong reducing power, so that the material in contact with the semiconductor has a redox action. This redox action is called a photocatalytic action, and a semiconductor exhibiting such a photocatalytic action is called a photocatalyst. As such a photocatalyst, particulate titanium oxide, tungsten oxide or the like exhibiting a high photocatalytic action is known.

  Such a particulate photocatalyst can, for example, decompose organic substances that cause malodor by photocatalysis. Therefore, for example, a photocatalyst layer composed of a particulate photocatalyst is formed on the surface of an organic base material such as wallpaper or film, and the organic base material on which the photocatalyst layer is formed is attached to an indoor interior material. Therefore, prevention of bad odor in the indoor space can be expected.

  However, if a photocatalyst layer is formed directly on the surface of an organic substrate such as wallpaper or film, the contact surface of the organic substrate in contact with the photocatalyst layer is decomposed by the photocatalytic action, and the photocatalyst layer easily peels off. There was a thing.

  Therefore, in order to suppress deterioration of the adhesion interface between the photocatalyst layer and the organic base material, that is, deterioration of adhesion, a precoat liquid is applied in advance to the surface of the organic base material to form a precoat layer. A photocatalyst layer is formed by applying a photocatalyst dispersion liquid thereon. Patent Document 1 discloses a precoat liquid used for such a purpose, which includes a silicon-modified resin, a polysiloxane-containing resin, or a colloidal silica-containing resin.

International Publication No. 97/000134

  However, even if the precoat layer is formed between the photocatalyst layer and the organic substrate in this way, the adhesion between the precoat layer and the photocatalyst layer becomes insufficient, the photocatalyst layer peels off, and the photocatalytic action is sufficient. There was a problem that could not be demonstrated.

  Then, the subject of this invention is providing the manufacturing method of the photocatalyst structure which is excellent in the adhesiveness of the precoat layer on a base material, and a photocatalyst layer, and shows a high photocatalytic action.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a method for producing a photocatalyst structure having excellent adhesion between the precoat layer and the photocatalyst layer on the substrate and exhibiting a high photocatalytic action. The invention has been completed.

That is, the present invention comprises the following configurations (1) to (6).
(1) A method for producing a photocatalyst structure having the following steps (a) and (b).
(A) The process of apply | coating the precoat liquid containing a metal alkoxide compound on a base material, and forming a precoat layer.
(B) A step of forming a photocatalyst layer by applying a photocatalyst coating solution on the precoat layer before the hydrolysis reaction or polycondensation reaction of the metal alkoxide compound is completed.
(2) The method for producing a photocatalyst structure according to (1), wherein the precoat liquid further contains an inorganic layered compound.
(3) The method for producing a photocatalyst structure according to (1) or (2), wherein the photocatalyst coating liquid contains at least photocatalyst particles and spherical particles having a particle diameter of 100 nm to 1 μm.
(4) The method for producing a photocatalyst structure according to (3), wherein the content of the spherical particles is 5 to 65 parts by mass with respect to 100 parts by mass of the total solid content in the photocatalyst coating liquid.
(5) A photocatalytic functional product having a photocatalyst structure obtained by the method according to any one of (1) to (4) on at least a part of the substrate surface.
(6) The photocatalytic functional product according to (5), wherein the substrate is a wallpaper or a film.

  ADVANTAGE OF THE INVENTION According to this invention, the photocatalyst structure which has the photocatalyst layer which is excellent in adhesiveness on an organic base material, and shows a high photocatalytic action can be obtained. Therefore, the present invention can be widely used as a method capable of providing a photocatalytic layer exhibiting photocatalytic activity over a long period of time on a substrate, and can provide a photocatalytic functional product exhibiting high photocatalytic activity over a long period of time.

  Embodiments of the present invention will be described in detail.

  The method for producing a photocatalyst structure of the present invention includes a photocatalyst coating solution on a precoat layer after the precoat solution is applied on a substrate and before the hydrolysis reaction or polycondensation reaction of the metal alkoxide compound contained in the precoat solution is completed. Is applied to form a photocatalyst layer.

(Base material)
The substrate in the present invention is an inorganic substrate or an organic substrate.
Examples of the inorganic base material include glass, concrete, plaster, and metal. Examples of the organic base material include ethylene-vinyl acetate copolymer resin, ethylene-methacrylic acid copolymer resin, and ethylene-methyl methacrylate. Polyester resins such as copolymer resin, polyethylene terephthalate, polyethylene naphthalate, polylactic acid, biodegradable polyester, polyester-based liquid crystal polymer; ethylenediamine-adipic acid polycondensate (nylon-66), nylon-6, nylon-12 Polyamide resins such as polyamide liquid crystal polymers; polyether resins such as polycarbonate resins, polyphenylene oxide, polymethylene oxide and acetal resins; polysaccharide resins such as cellulose and its derivatives; Polyolefin resin: polystyrene, poly-α-methylstyrene, styrene-ethylene-propylene copolymer (polystyrene-poly (ethylene / propylene) block copolymer), styrene-ethylene-butene copolymer (polystyrene-poly ( (Ethylene / butene) block copolymer), styrene-ethylene-propylene-styrene copolymer (polystyrene-poly (ethylene / propylene) -polystyrene block copolymer), ethylene-styrene copolymer, etc. Resin: Polyvinyl alcohol resin such as polyvinyl alcohol, polyvinyl butyral, ethylene-vinyl alcohol copolymer resin, etc .; Polymethyl methacrylate, methacrylic acid ester, acrylic acid ester, methacrylic acid amide, acrylic acid amino acid as monomer Acrylic resins containing chlorinated resins; Chlorinated resins such as polyvinyl chloride and polyvinylidene chloride; polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene -Fluororesin such as hexafluoropropylene copolymer and polyvinylidene fluoride; Paper made of plant fibers such as cellulose;

(Precoat liquid)
The precoat liquid in the present invention contains a metal alkoxide compound and a solvent, and optionally contains an inorganic layered compound, an organic acid, phosphoric acid or a salt thereof. The state of the precoat liquid may be a fluid liquid, or a sol or gel. The precoat liquid becomes a precoat layer for forming a photocatalyst layer on the surface of the substrate.

(Metal alkoxide compound)
The metal alkoxide compound contained in the precoat liquid functions as an adhesive layer that bonds the substrate and the photocatalyst layer by performing a hydrolysis reaction and a polycondensation reaction.
Examples of the metal alkoxide compound include the molecular formula MR ¹ _x (OR ² ) _y (M represents Si, Al, Mg, Ti, Zr, V, Nb, W, Ta, Fe, Co, Ni, Zn, or Cu). , X = 0 to 6, y = 1 to 6, R ¹ and R ² are the same or different groups and represent an alkyl group having 1 to 6 carbon atoms.) And these metal alkoxide compounds And a partial hydrolyzate such as an oligomer obtained by condensation polymerization.
Specific examples thereof include silicon alkoxides such as tetraethoxysilane (ethyl silicate), tetramethoxysilane (methyl silicate), methyltriethoxysilane, and methyltrimethoxysilane, and hydrolysates and polymers of the silicon alkoxide. Etc. In addition, these metal alkoxide compounds may be used independently and may use 2 or more types together.
The concentration of the metal alkoxide compound in the precoat liquid is preferably 0.01 to 10% by mass in terms of the metal alkoxide compound in terms of the oxide of the metal with respect to the total amount of the precoat liquid. If the concentration of the metal alkoxide compound is less than 0.01% by mass, the adhesion between the precoat layer and the base material and the photocatalyst layer may be insufficient. If the concentration exceeds 10% by mass, sufficient photocatalytic activity is obtained. It may not be obtained. Moreover, when an inorganic layered compound is included in the precoat solution, the concentration of the metal alkoxide compound is 5 to 200 parts by weight of the metal alkoxide compound in terms of oxide of the metal with respect to 100 parts by weight of the inorganic layered compound, preferably Is preferably 10 to 100 parts by mass. If the concentration of the metal alkoxide compound is less than 5 parts by mass, the adhesion between the precoat layer, the substrate and the photocatalyst layer may be insufficient, and if it exceeds 200 parts by mass, sufficient photocatalytic activity may not be obtained. There is sex.

(Precoat liquid solvent)
As the solvent for the precoat liquid, a water-soluble organic solvent, water, a mixed solvent of water and a water-soluble organic solvent, or the like is usually used.
Examples of the water-soluble organic solvent include water-soluble alcohols such as methanol, ethanol, propanol, and butanol, acetone, and methyl ethyl ketone. In addition, a water-soluble organic solvent may be used independently and may use 2 or more types together. Usually, ethanol is used as the water-soluble alcohol.

(Inorganic layered compound)
The precoat liquid can further contain an inorganic layered compound.
By containing the inorganic layered compound, the precoat liquid can impart excellent mechanical strength and flexibility to the precoat layer.
The inorganic layered compound is not particularly limited as long as it can be dispersed in at least a solvent such as water. For example, bentonite, mica, vermiculite, montmorillonite, beidellite, saponite, hectorite, stevensite, smectite, kaoriite. Examples thereof include knight, sericite, pyrophyllite, dickite, talc, halosite, attapulgite, sepiolite, hydrotalcant, and nontronite. In addition, these inorganic layered compounds may be used independently and may use 2 or more types together.
When the inorganic layered compound is contained in the precoat solution, the concentration of the inorganic layered compound in the precoat solution is 0.01 to 10% by mass, preferably 0.1 to 8%, based on the total amount of the precoat solution. It is good that it is mass%.

  The precoat liquid can contain an organic acid or phosphoric acid or a salt thereof in addition to the inorganic layered compound and the metal alkoxide compound. An organic acid, phosphoric acid or a salt thereof serves as a dispersant for the inorganic layered compound, so that a uniform layer can be obtained.

(Organic acid or its salt)
The organic acid or a salt thereof is not particularly limited as long as it is soluble in the solvent of the above-mentioned precoat solution. For example, oxalic acid, ammonium oxalate, malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, pimelic acid And polyvalent carboxylic acids such as suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, ammonium polycarboxylate, and salts thereof. These organic acids or salts thereof may be used alone or in combination of two or more.
The total amount of the organic acid or its salt added is preferably 1 to 100 parts by mass per 100 parts by mass of the inorganic layered compound.

(Phosphoric acid or its salt)
Examples of phosphoric acid or salts thereof include phosphoric acid, pyrophosphoric acid, polyphosphoric acid or ammonium salts thereof, sodium salts, potassium salts, etc. Among these, phosphoric acid, ammonium dihydrogen phosphate, phosphoric acid, among others. Diammonium hydrogen is preferred. In addition, phosphoric acid or its salt may be used independently and may use 2 or more types together.
The total amount of phosphoric acid or a salt thereof added is preferably 1 to 100 parts by mass per 100 parts by mass of the inorganic layered compound.

(Preparation solution preparation)
The precoat liquid can be adjusted, for example, by adding a metal alkoxide compound to the solvent of the precoat liquid, but can be obtained by dispersing the inorganic layered compound in the solvent of the precoat liquid and further adding the metal alkoxide compound. I can do it. In addition, a mixed solution in which an organic acid or phosphoric acid or a salt thereof is dissolved in the same solvent as the solvent of the precoat solution is added to the solvent of the precoat solution in which the inorganic layered compound is dispersed, and a metal alkoxide compound is added. Can also be obtained. These steps may be performed while stirring as necessary, or may be performed while heating.

The pH of the precoat solution is adjusted to 1.0 to 11.0, preferably 1.0 to 10.0, and more preferably 1.0 to 6.0. When the pH is lower than 1.0, there is a possibility that the coating equipment may be corroded. When the pH is higher than 11.0, the precoat liquid may be thickened and solidified.
In order to adjust the pH within the above range, a base may be usually added. Examples thereof include ammonia, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide. An aqueous solution of lanthanum hydroxide and the like can be mentioned, among which aqueous ammonia and aqueous sodium hydroxide are preferably used.

(Photocatalyst coating solution)
Hereinafter, the photocatalyst coating solution will be described in detail.
The photocatalyst coating liquid preferably contains photocatalyst particles and a dispersion medium, and further contains spherical particles having a particle diameter of 100 nm to 1 μm.

(Photocatalyst particles)
The photocatalyst particles are, for example, a semiconductor that exhibits a photocatalytic action by irradiation with ultraviolet rays or visible rays, and specifically, one kind or two or more kinds of oxides and nitrides of a metal element exhibiting a specific crystal structure. , Sulfides, oxynitrides, oxysulfides, nitrofluorides, oxyfluorides, oxynitrofluorides, and the like.
Examples of metal elements include Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, and Cu. , Ag, Au, Zn, Cd, Ga, In, Tl, Ge, Sn, Pb, Bi, La, Ce, and the like.
Of these, oxides of Ti, W, and Nb are preferable, and metatitanic acid, titanium oxide, tungsten oxide, and the like are particularly preferable. The photocatalyst particles may be used alone or in combination of two or more.

(Metatitanic acid)
Metatitanic acid (H ₂ TiO ₃ , TiO (OH) ₂ , β-titanium hydroxide) can be obtained, for example, by heating and hydrolyzing an aqueous solution of titanyl sulfate.
The particle diameter of metatitanic acid is not particularly limited, but from the viewpoint of photocatalysis, the average dispersed particle diameter is usually 20 to 150 nm, preferably 40 to 100 nm. BET specific surface area of the metatitanic acid is not particularly limited, from the viewpoint of photocatalytic activity, usually 100 to 500 m ² / g, preferably from 300~400m ² / g.

(Titanium oxide)
Titanium oxide (TiO ₂ ) is obtained, for example, by (i) a method of obtaining a precipitate by adding a base to this without heating an aqueous solution of titanyl sulfate or titanium chloride, and firing this precipitate, (ii) titanium It can be obtained by adding water, an acidic aqueous solution, a basic aqueous solution or the like to the alkoxide to obtain a precipitate, and baking the precipitate, or (iii) a method of baking metatitanic acid. The titanium oxide obtained by these methods can be made into a desired crystal type such as anatase type, brookite type, rutile type, etc. by adjusting the baking temperature and baking time at the time of baking.
In addition to the above method, titanium oxide is disclosed in JP-A-2001-72419, JP-A-2001-190953, JP-A-2001-316116, JP-A-2001-322816, and JP-A-2002-29749. Gazette, JP 2002-97019, WO 01/10552, JP 2001-212457, JP 2002-239395), WO 03/080244, WO 02/053501, JP 2007-69093, Chemistry Letters, Vol.32, No.2, P.196-197 (2003), Chemistry Letters, Vol.32, No.4, P.364-365 (2003), Chemistry Letters , Vol. 32, No. 8, P. 772-773 (2003), Chem. Mater., 17, P. 1548-1552 (2005), and the like. JP 2001-278625 A, JP 2001-278626 A, JP 2001-278627 A, JP 2001-302241 A, JP 2001-335321 A, JP 2001-354422 A, It can also be obtained by the methods described in JP2002-29750, JP2002-47012, JP2002-60221, JP2002-193618, JP2002-249319, and the like. .
The particle diameter of titanium oxide is not particularly limited, but from the viewpoint of photocatalysis, the average dispersed particle diameter is usually 20 to 150 nm, preferably 40 to 130 nm.
BET specific surface area of the titanium oxide is not particularly limited, from the viewpoint of photocatalytic activity, usually 100 to 500 m ² / g, preferably from 300~400m ² / g.

(Tungsten oxide)
Tungsten oxide (WO ₃ ) is obtained, for example, by (i) a method of adding tungstic acid as a precipitate by adding an acid to an aqueous solution of tungstate, and firing this tungstic acid, (ii) ammonium metatungstate, para It can be obtained by a method of thermally decomposing by heating ammonium tungstate.
The particle diameter of tungsten oxide is not particularly limited, but from the viewpoint of photocatalysis, the average dispersed particle diameter is usually 50 to 200 nm, preferably 80 to 170 nm. BET specific surface area of tungsten oxide is not particularly limited, from the viewpoint of photocatalytic activity, typically 5 to 100 m ² / g, preferably from 20 to 50 m ² / g.

(Noble metal-supported photocatalyst particles)
For the purpose of improving the photocatalytic activity, the photocatalyst particle can be a noble metal-supported photocatalyst particle having a noble metal supported on the surface thereof.
Examples of the noble metal include Cu, Pt, Au, Pd, Ag, Ru, Ir, and Rh. Among these, Cu, Pt, Au, and Pd are preferable from the viewpoint of obtaining high photocatalytic activity.

These noble metals are used alone or in combination of two or more.
The amount of noble metal used is usually 0.01 parts by mass or more in terms of sufficiently improving the photocatalytic action with respect to the amount of photocatalyst particles used of 100 parts by mass. 1 part by mass or less, preferably 0.05 part by mass to 0.6 part by mass.

  The content of the photocatalyst particles in the photocatalyst coating liquid is 4 to 10% by mass, preferably 5 to 8% by mass with respect to the total amount of the photocatalyst coating liquid, and is 100 parts by mass with respect to the total solid content in the photocatalyst coating liquid. 30 parts by mass or more, preferably 35 parts by mass or more, and more preferably 40 parts by mass or more. When the content of the photocatalyst particles is less than 30 parts by mass with respect to 100 parts by mass of the total solid content in the photocatalyst coating liquid, the amount of the photocatalyst particles in the obtained photocatalyst layer is reduced. May not be obtained.

(Spherical particles)
The photocatalyst coating liquid can contain spherical particles.
When the photocatalyst coating liquid contains spherical particles, it is possible to form a photocatalyst layer that is not noticeably glossy.
As the spherical particles, inorganic and organic spherical particles are used, and they can be used as matting particles.
The inorganic matting particles need only contain at least Si and O. Examples thereof include silicon oxides such as silica sol and colloidal silica, hydroxides, and hydrates.
Examples of organic matting particles include spherical particles such as polymethyl methacrylate, polycarbonate, polystyrene, polyester, polyimide, epoxy resin, walnuts, and microcapsules. These may be used alone or in combination of two or more.

  These matting particles have a dispersed particle diameter of 100 nm to 1 μm, preferably 150 nm to 800 nm, and more preferably 200 nm to 600 nm. When the dispersed particle diameter of the matting particles is less than 100 nm, the gloss of the resulting photocatalyst layer increases. When the particle size exceeds 1 μm, the exposed portion of the matting particles of the resulting photocatalyst layer increases, and a sufficient photocatalyst layer and precoat are obtained. Adhesiveness with the layer or substrate cannot be obtained.

  The content of these matting particles is 5 to 65 parts by mass, preferably 8 to 60 parts by mass, and more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the solid content in the photocatalyst coating liquid. When the content of the matting particles is less than 5 parts by mass, the gloss of the surface of the product provided with the photocatalyst layer is increased. On the other hand, when it exceeds 65 parts by mass, the amount of the matting particles in the resulting photocatalyst layer is The product including this photocatalyst layer may not have sufficient photocatalytic activity and adhesion between the photocatalyst layer and the precoat layer or the substrate.

(Dispersion medium)
As the dispersion medium, an aqueous solvent mainly containing water is usually used. Specifically, the aqueous solvent may be a water-soluble organic solvent alone or water alone. Further, it may be a mixed medium of water and a water-soluble organic solvent.
Examples of the water-soluble organic solvent include water-soluble alcohols such as methanol, ethanol, propanol, and butanol, acetone, and methyl ethyl ketone. In addition, a water-soluble organic solvent may be used independently and may use 2 or more types together.
Usually, methanol or ethanol is used as the water-soluble alcohol. Preferably methanol is used. Further, in the case of using a water-soluble alcohol, the content of the water-soluble alcohol should be 10 to 70% by mass with respect to the total amount of the photocatalyst coating liquid. Preferably it is 25-60 mass%.

(Preparation of photocatalyst coating solution)
When preparing the photocatalyst coating liquid, the mixing order and mixing method of the photocatalyst particles and the dispersion medium, if necessary, the matting particles are not particularly limited, and may be performed while stirring, if necessary. You may carry out, heating.
When using a commercially available photocatalyst coating solution, a dispersion medium and, if necessary, matting particles may be added to the photocatalyst coating solution and mixed.
When two or more types of photocatalyst particles are used, for example, a photocatalyst coating solution in which each photocatalyst particle is added to a dispersion medium is obtained, mixed while appropriately adjusting these photocatalyst coating solutions, dispersed, and then dispersed. A medium and, if necessary, matting particles may be added and mixed.
At this time, if necessary, an inorganic compound, an organic compound, or a known additive can be added in addition to the photocatalyst particles and the matting particles. These may be used alone or in combination of two or more.
The dispersion treatment can be performed by a normal method using a medium stirring type disperser, for example.

  As a commercially available photocatalyst coating liquid, for example, “PC-201”, “PC-401” (titanium oxide sol, manufactured by Sumitomo Chemical Co., Ltd.), “TS-S4110”, “TS-S4420” are added to a titanium oxide dispersion. And “TS-S4230” (titanium oxide sol, manufactured by Sumitomo Chemical Co., Ltd.), “Vilaral Nb-X10” (average particle size 16 nm, manufactured by Taki Chemical Co., Ltd.), etc. can be used as the niobium oxide dispersion.

  Examples of the inorganic compound include aluminum (water) oxides such as amorphous alumina and alumina sol; aluminosilicates such as zeolite and kaolinite; magnesium oxide, calcium oxide, strontium oxide, barium oxide, magnesium hydroxide, hydroxide And alkaline earth metal (hydroxide) oxides such as calcium, strontium hydroxide and barium hydroxide; calcium phosphate; molecular sieves; or activated carbon. The aluminum (hydroxide) means aluminum oxide or aluminum hydroxide, and the same applies to alkaline earth metal (water) oxide.

  Examples of organic compounds include polycondensates of organic polysiloxane compounds, phosphates, fluorine-based polymers, silicon-based polymers, acrylic resins, polyester resins, melamine resins, urethane resins, alkyd resins, and the like.

Further, adsorbents, antifoaming agents, surfactants, viscosity modifiers and the like can be added as known additives.
Examples of the viscosity modifier include clay minerals such as bentonite, montmorillonite, and smectite.
The addition amount of the viscosity modifier is 0.1 to 5% by weight, preferably 0.3 to 4% by weight, based on the total amount of the photocatalyst coating liquid.
Examples of commercially available clay minerals include “Smecton SA”, “Kunipia F” (manufactured by Kunimine Industry Co., Ltd.), “Lucentite” (manufactured by Corp Chemical Co., Ltd.), and the like.

In addition, the photocatalyst coating liquid may contain a component that becomes a binder. Examples of the binder component include metal alkoxide compounds. For example, the molecular formula MR ¹ _x (OR ² ) _y (M is Si, Al, Mg, Ti, Zr, V, Nb, W, Ta, Fe, Co, Ni, Zn or Cu, wherein x = 0 to 6, y = 1 to 6, R ¹ and R ² are the same or different groups and represent an alkyl group having 1 to 6 carbon atoms.) And partial hydrolysates such as oligomers obtained by condensation polymerization of these metal alkoxide compounds.
Specific examples thereof include tetraethoxysilane (ethyl silicate), tetramethoxysilane (methyl silicate), methyltriethoxysilane, methyltrimethoxysilane, and a hydrolyzate or polymer of silicon alkoxide. In addition, these metal alkoxide compounds may be used independently and may use 2 or more types together.

  Moreover, you may contain the amorphous Zr-O type particle | grain (it says the particle | grains of the compound containing Zr and O) which cannot specify a crystal structure by X-ray diffraction as a binder. When amorphous Zr—O-based particles are added as a binder component to the photocatalyst coating liquid, a photocatalytic layer can be formed without inhibiting the photocatalytic action of the photocatalyst particles. These amorphous Zr—O-based particles may be used alone or in combination of two or more.

  The particle diameter of the amorphous Zr—O-based particles is an average dispersed particle diameter, and is usually 5 to 70 nm, preferably 10 to 60 nm. The average dispersed particle size is measured using a sub-micron particle size distribution measuring device (“N4 Plus” manufactured by Beckman Coulter, Inc.) and automatically in a monodisperse mode by software attached to this device. The result obtained by analysis was defined as the average dispersed particle size (nm).

As the amorphous Zr-O-based particles, for example, zirconium oxalate, zirconium hydroxide, zirconium oxychloride, zirconium zirconium chloride, zirconium nitrate, zirconium sulfate, zirconium acetate, ammonium zirconium carbonate, which does not show a specific crystal structure, Examples thereof include potassium zirconium carbonate, zirconium zirconium phosphate, zirconium propionate, zirconium metal alkoxide and the like.
In addition, zirconium complexes and complex salts having at least one of a hydroxyl group, a carbonic acid group, and an alkylcarboxy group, and high molecular zirconium compounds thereof can be used. Of these, zirconium hydroxide and zirconium oxalate are preferably used, and zirconium hydroxide is more preferably used. Amorphous Zr—O-based particles may be used alone or in combination of two or more.

The content of amorphous Zr-O-based particles in the photocatalyst coating liquid is 3 to 30 parts by mass, preferably 5 to 25 parts by mass with respect to 100 parts by mass of the total solid content in the photocatalyst coating liquid. When the content of the amorphous Zr-O-based particles is less than 3 parts by mass, the adhesion of the photocatalyst layer is lowered. On the other hand, when the content exceeds 30 parts by mass, the photocatalyst coating liquid is thickened and gel It may become. The weight of the amorphous Zr—O-based particles is expressed in terms of oxide (ZrO ₂ ).

(Method for producing photocatalyst structure)
The method for producing a photocatalyst structure of the present invention includes a step (a) of applying a precoat liquid containing a metal alkoxide compound on a substrate to form a precoat layer, and a hydrolysis reaction or polycondensation of the metal alkoxide compound. Before the reaction is completed, the method has a step (b) of applying a photocatalyst coating liquid containing photocatalyst particles on the precoat layer to form a photocatalyst layer. Furthermore, it is preferable to heat after the step (b) in order to complete the hydrolysis reaction or polycondensation reaction of the metal alkoxide compound.
The photocatalyst structure obtained through such steps (a) and (b) is excellent in adhesion between the precoat layer on the substrate and the photocatalyst layer, and exhibits high photocatalytic action.

(Application of precoat solution)
Examples of the method for applying the precoat liquid in the step (a) include known methods such as a printing method, a sheet forming method, a spray spraying method, a dip coating method, a spin coating method, a bar coating method, a gravure coating method, and a knife coating method. Etc.

Before the metal alkoxide compound in the step (b) completes the hydrolysis reaction or polycondensation reaction, it is within 5 minutes, preferably within 3 minutes, preferably 60 ° C. or less, preferably after applying the precoat solution to the substrate surface. Is to apply the photocatalyst coating liquid at a temperature of 50 ° C. or lower. If it is within the above range, the adhesion between the precoat layer and the photocatalyst layer is achieved by applying a photocatalyst coating liquid on the alkoxy group contained in the metal alkoxide compound at the stage where the unreacted one is still present. Can be greatly improved.
The polycondensation reaction of a metal alkoxide compound refers to a reaction that mainly forms a siloxane bond when M in the above-described molecular formula MR ¹ _x (OR ² ) _y is Si, for example.

(Application of photocatalyst coating solution)
Examples of the application method of the photocatalyst coating liquid in the step (b) include known methods such as a printing method, a sheet forming method, a spray spraying method, a dip coating method, a spin coating method, a bar coating method, a gravure coating method, and a knife coating method. The method etc. are mentioned. Moreover, after application | coating, it is preferable to dry at 25 degreeC-200 degreeC under a normal pressure for 10 second-15 minutes.

In order to complete the hydrolysis reaction and polycondensation reaction of the metal alkoxide compound after the step (a) and the step (b), the heating may be appropriately adjusted depending on the amount of the applied precoat solution. It is preferable to heat for a second to 15 minutes.
The photocatalyst structure which is excellent in the adhesiveness between the precoat layer on the substrate and the photocatalyst layer can be obtained by heating in this way and surely completing the hydrolysis reaction and polycondensation reaction of the metal alkoxide compound.
The heating method is not particularly limited, and examples thereof include microwave irradiation, far-infrared irradiation, laser irradiation, warm air by a warm air generator such as a dryer, and a heating method by energization.

(Photocatalytic functional products)
A photocatalytic functional product is a product having the above-described photocatalytic structure on at least a part of the surface of a base material. Even if it is used where ultraviolet rays or visible rays are irradiated for a long period of time, a precoat layer and a photocatalytic layer, and thus a photocatalytic layer In particular, when tungsten oxide carrying platinum is used as photocatalyst particles, light from a visible light source such as a fluorescent lamp, a sodium lamp, or a light-emitting diode is not deteriorated. Even in an indoor environment that only receives light, high photocatalytic action can be maintained by light irradiation, and when titanium oxide is used, particularly excellent photocatalytic action can be maintained for a long time by ultraviolet irradiation.

Examples of photocatalytic functional products include ceiling materials, tiles, glass, wallpaper, wall materials, films, floors, and other building materials, automotive interior materials (automotive instrument panels, automotive seats, automotive ceiling materials, automotive glass, etc.) ), Household appliances such as refrigerators, air conditioners and air purifiers, textile products such as clothes and curtains, straps for trains, elevator buttons, etc. Wallpaper or film is preferred.
These photocatalyst functional products reduce the concentration of volatile organic substances such as formaldehyde and acetaldehyde, aldehydes, mercaptans, ammonia and other malodorous substances, nitrogen oxides, and staphylococcus aureus by irradiation with indoor lighting. And pathogenic bacteria such as Escherichia coli, Bacillus anthracis, tuberculosis, cholera, diphtheria, tetanus, plague, shigella, botulinum, and legionella, turkey herpes virus, Marek's disease virus, infectious bursal disease virus, Newcastle disease virus, infectious bronchitis virus, infectious laryngotracheitis, avian encephalomyelitis virus, chicken anemia virus, fowlpox virus, avian reovirus, avian leukemia virus, reticuloendotheliosis virus, avian adenovirus and hemorrhagic Enteritis virus, herpes virus, smallpox Viruses such as virus, cowpox virus, chickenpox virus, measles virus, adenovirus, coxsackie virus, calicivirus, retrovirus, coronavirus, avian influenza virus, human influenza virus, swine influenza virus, norovirus and its recombinants, Allergens such as mite allergens and pollen allergens can be inactivated, killed, decomposed and removed. Furthermore, if the photocatalytic functional product is irradiated with light, especially visible light, it exhibits sufficient hydrophilicity and exhibits anti-fogging properties, as well as being able to be easily wiped off simply by applying water to the dirt. In addition, charging can be prevented.

When the photocatalytic functional product is wallpaper, a resin layer is formed on at least one surface of the base sheet, and a precoat layer and a photocatalyst layer are sequentially provided on the resin layer.
Base sheets include flame retardant paper for wallpaper (sheets mainly made of pulp, sheets treated with flame retardants such as guanidine sulfamate and guanidine phosphate), ordinary paper such as aluminum hydroxide paper and inorganic paper, etc. Is mentioned.
Examples of the resin layer include a layer made of an ethylene-vinyl acetate copolymer resin, a vinyl chloride resin, an ethylene-methacrylic acid copolymer resin, an ethylene-methyl methacrylate copolymer resin, an acrylic resin, and the like. The resin layer may contain a capsule foaming agent and a chemical foaming agent before foaming treatment.
Further, when the photocatalytic functional product is a film, a precoat layer and a photocatalyst layer are sequentially provided on the film.

  Examples The present invention will be described in detail by examples, but the present invention is not limited to these examples.

  About the measurement of each physical property in an Example and a comparative example, and evaluation of the photocatalytic activity, it carried out with the following method.

(Crystal type)
An X-ray diffraction spectrum was measured using an X-ray diffractometer (“RINT2000 / PC” manufactured by Rigaku Corporation), and a crystal type was determined from the spectrum.

(BET specific surface area)
It measured by the nitrogen adsorption method using the specific surface area measuring apparatus ("Monosorb" by Yuasa Ionics Co., Ltd.).

(Evaluation of photocatalytic activity)
Ultraviolet light intensity of ² mW / cm ^{2 on} the 8 cm × 8 cm glass with the photocatalyst layer (measured by attaching a UV detector “UD-36” to Topcon's UV intensity meter “UVR-2”) The sample was irradiated with UV light from a black light for 16 hours, and this was used as a sample for photocatalytic activity measurement.
Next, this photocatalytic activity measurement sample is put in a gas bag (internal volume 3 L) and sealed, and then the inside of the gas bag is evacuated, and then the volume ratio of oxygen and nitrogen is 1: 4. 1120 mL of the mixed gas was sealed, and nitrogen gas containing 1% by volume of acetaldehyde was sealed therein so that the concentration of acetaldehyde in the gas bag was 100 ppm, and kept in the dark at room temperature for 1 hour. Then, using a commercially available white fluorescent light as a light source, a gas bag was installed so that the illuminance near the measurement sample was 6000 lux (measured with illuminance meter “T-10” (manufactured by Konica Minolta Sensing Co., Ltd.)) Acetaldehyde was decomposed. The intensity of ultraviolet light in the vicinity of the measurement sample was 40 μW / cm ² [measured by attaching a UV receiver “UD-36” manufactured by the company to a UV intensity meter “UVR-2” manufactured by Topcon Corporation]. The gas in the gas bag was sampled every 1.5 hours after the fluorescent lamp was irradiated, and the concentration of carbon dioxide was measured with a gas chromatograph (“GC-14B” manufactured by Shimadzu Corporation). The concentration of carbon dioxide after 3 hours to 6 hours after light irradiation was measured, and the carbon dioxide production rate (ppm / h) was calculated from this value, and this was evaluated as the photocatalytic activity. That is, the larger the carbon dioxide production rate, the higher the photocatalytic activity.

(Adhesion test)
The cellophane tape was attached to the 8 cm × 8 cm glass with a photocatalyst layer to be measured, and then peeled off to visually evaluate the film on the glass.
Evaluation result 1 ... almost no peeling of the film
2 ... Peeling of film is clearly seen

(Production Example 1-Preparation of amorphous Zr-O-based particles)
Basic zirconium sol by adding 64 g of anhydrous citric acid to 1000 g of “ZSL-10T” (Daiichi Rare Element Chemical Co., Ltd.) and then adding 120 g of 25 wt% aqueous ammonia. A was obtained. The zirconium concentration of the obtained basic zirconium sol A was 12.8% by weight in terms of ZrO ₂ . This basic zirconium sol A was vacuum-dried to obtain amorphous zirconium A having an amorphous crystal form. The average dispersed particle size of amorphous zirconium A was measured using a submicron particle size distribution analyzer (“N4 Plus” manufactured by Beckman Coulter, Inc.), and found to be 31.3 nm.

(Production Example 2-Preparation of amorphous Zr-O-based particles)
Basic zirconium sol by adding 64 g of anhydrous citric acid to 1000 g of “ZSL-10T” (Daiichi Rare Element Chemical Co., Ltd.) and then adding 120 g of 25 wt% aqueous ammonia. B was obtained. Next, by repeating the operation of adding a 2.5 wt% aqueous solution of ammonium oxalate to the basic zirconium sol B and purifying and concentrating it by ultrafiltration, the zirconium concentration is 14.6 wt% in terms of ZrO _2. A zirconium sol was obtained. This zirconium sol was vacuum-dried to obtain amorphous zirconium B having an amorphous crystal form. The average dispersed particle size of amorphous zirconium B was measured using a submicron particle size distribution analyzer (“N4 Plus” manufactured by Beckman Coulter, Inc.), and was found to be 30.1 nm.

(Production Example 3-Preparation of photocatalyst particles and dispersion medium)
A reaction vessel comprising a pH electrode and a pH controller connected to the pH electrode and having a mechanism for adjusting the pH to a constant level by supplying 25% by mass of aqueous ammonia (that is, in this reaction vessel, When the pH became lower than the set value, ammonia water began to be supplied and continuously supplied until the pH reached the set value), and 30 kg of ion-exchanged water was added, and the set value of the pH controller was set to pH 4.
On the other hand, after dissolving 75 kg of titanium oxysulfate in 50 kg of ion-exchanged water, 30 kg of 35% hydrogen peroxide solution was further added under cooling to prepare a mixed solution.
While stirring the inside of the reaction vessel at 42 rpm, the mixed solution was added to the reaction vessel at 530 mL / min, reacted with ammonia water supplied to the reaction vessel by a pH controller, and adjusted to pH. An acidic aqueous solution containing titanium oxysulfate was obtained. At this time, the reaction temperature (internal temperature of the reaction vessel) was in the range of 20 ° C to 30 ° C. After completion of the addition of the mixed solution, the acidic aqueous solution containing titanium oxysulfate in the reaction vessel was kept for 1 hour with stirring, and then 25% by mass aqueous ammonia was supplied to obtain a slurry product. The obtained slurry-like product was filtered and rinsed, and then a solid (cake) was obtained. The total amount of ammonia water supplied to the reaction vessel was 90 kg, which was twice the theoretical amount required to change titanium oxysulfate to titanium hydroxide.

The obtained solid (cake) was put into 12 pieces of stainless steel bats (30 cm × 40 cm) by 2.3 kg, and 12 pieces of these bats were put into a box-type dryer ("Supertemp oven HP-" manufactured by Asahi Kagaku Co., Ltd.). 60 ”, internal volume: 216 liters), kept at 115 ° C. for 5 hours under a flow of dry air of 40 m ³ / hr, and then kept at 250 ° C. for 5 hours for drying, resulting in a BET specific surface area of A dry powder of 18.0 m ² / g was obtained. The maximum water vapor partial pressure in the dryer at this time was 27.4 kPa. The obtained dry powder was calcined in an air atmosphere at 350 ° C. for 2 hours, and then cooled to room temperature to obtain a total of 22 kg of particulate titanium oxide powder.

Next, 950 g of ammonium dihydrogen phosphate (Wako Special Grade Reagent) was dissolved in 87.6 kg of ion-exchanged water, and 22 kg of the titanium oxide powder obtained above was further added to obtain a titanium oxide particle liquid. This titanium oxide particle liquid was subjected to a dispersion treatment under the following conditions using a medium agitating disperser (“Dynomill KDL-PILOT A type” manufactured by Shinmaru Enterprises Co., Ltd.) to obtain a crude titanium oxide particle dispersion A. Got.
Dispersion medium: Zirconia beads with a diameter of 0.3 mm 4.2 kg
Processing temperature: 20 ° C
Total processing time: about 240 minutes Stirring speed: Peripheral speed 8m / sec Flow rate: 2L / min Processing liquid circulation: Available

Further, the crude titanium oxide particle dispersion A obtained above is subjected to a second dispersion treatment under the following conditions using a medium stirring type disperser (“Ultra Apex Mill UAM-5” manufactured by Kotobuki Giken Kogyo Co., Ltd.). The crude titanium oxide particle dispersion B was obtained. The content of ammonium phosphate in the crude titanium oxide particle dispersion B was 0.03 mol times the titanium oxide particles.
Dispersion medium: 13 kg of zirconia beads having a diameter of 0.05 mm
Processing temperature: 20 ° C
Total processing time: about 400 minutes Number of revolutions: 2000 rpm
Flow rate: 1 L / min Treatment liquid circulation: Available

  The obtained crude titanium oxide particle dispersion B was centrifuged to remove coarse particles, and further adjusted with water so that the solid content concentration was 18.74% by mass to obtain a titanium oxide particle dispersion. The average dispersed particle size of the titanium oxide particles in the titanium oxide particle dispersion was measured using a submicron particle size distribution analyzer (“N4 Plus” manufactured by Beckman Coulter, Inc.), and was found to be 91.1 nm. .

(Production Example 4-Preparation of binder component-containing photocatalyst dispersion)
50.1 g of methanol was added to 38.1 g of the titanium oxide particle dispersion, and 4.1 g of amorphous zirconium A obtained in Production Example 1 and 7.9 g of amorphous zirconium B obtained in Production Example 2 were added. Thus, a zirconium-containing titanium oxide particle dispersion was obtained. The content of titanium oxide in 100 parts by mass of the zirconium-containing titanium oxide particle dispersion is 7.13 parts by mass, and the titanium oxide particles are 81 parts by mass with respect to 100 parts by mass of the total solid content in the zirconium-containing titanium oxide particle dispersion. Part, the total amount of amorphous zirconium A and amorphous zirconium B was 19 parts by mass.

(Production Example 5-Preparation of Matting Particle-Containing Photocatalyst Dispersion)
85.8 g of the zirconium-containing titanium oxide particle dispersion obtained in Production Example 4 and colloidal silica (“MP-4540M” manufactured by Nissan Chemical Industries, Ltd., concentration: 40.6%, particle size: 450 nm as matting particles) ) 14.2 g was added to obtain a titanium oxide coating solution C. The content of titanium oxide in 100 parts by mass of the titanium oxide coating liquid C is 6.12 parts by mass, and the titanium oxide particles are 45.9 parts by mass with respect to 100 parts by mass of the total solid content in the titanium oxide coating liquid C. The total amount of amorphous zirconium A and amorphous zirconium B was 10.8 parts by mass, and the amount of colloidal silica was 43.3 parts by mass.

(Production Example 6—Preparation of viscosity modifier-containing photocatalyst dispersion)
49.8 g of titanium oxide coating liquid C obtained in Production Example 5 and 0.2 g of bentonite (“Kunipia F” manufactured by Kunimine Industries Co., Ltd.) as a viscosity modifier were added to obtain titanium oxide coating liquid D.

(Production Example 7-Preparation of precoat solution)
20 g of bentonite (“Kunipia F” manufactured by Kunimine Kogyo Co., Ltd.) was added to 647 g of water, and dispersion treatment was performed for 1 hour at a rotation speed of 10,000 rpm using a homogenizer. 2.4 g of oxalic acid dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.), 53.7 g of water, and 90 g of ethanol were added to 150 g of the obtained bentonite dispersion (solid content concentration 3 mass%). Thereafter, 3.9 g of highly pure ethyl silicate (manufactured by Tama Chemical Industry Co., Ltd.) was added to the dispersion, and the pH was adjusted to 4.0 using an aqueous ammonia solution to obtain a precoat solution. The amount of high purity pure ethyl silicate in terms of oxide (SiO ₂ ) added to 100 parts by mass of bentonite (“Kunipia F” manufactured by Kunimine Kogyo Co., Ltd.) was 25 parts by mass.

Example 1
A precoat solution was applied to 8 cm × 8 cm glass, and was rotated for 60 seconds at a rotation speed of 500 rpm using a spin coater. Within 2 minutes after application with a spin coater, the titanium oxide coating solution D was applied to the obtained glass as it was at 25 ° C., and was rotated using a spin coater at a rotational speed of 1200 rpm for 60 seconds. The obtained glass was heated at 90 ° C. for 5 minutes to complete the hydrolysis reaction and polycondensation reaction of high purity ethyl silicate, and the solvent of the titanium oxide coating solution was removed to obtain a glass with a photocatalyst layer. .

  The evaluation results of the obtained glass with a photocatalyst layer are shown in Table 1.

(Comparative Example 1)
A precoat solution was applied to 8 cm × 8 cm glass, and was rotated for 60 seconds at a rotation speed of 500 rpm using a spin coater. The obtained glass was heated at 90 ° C. for 5 minutes to complete hydrolysis reaction and polycondensation reaction of high purity ethyl silicate. Thereafter, a titanium oxide coating solution D was applied to the obtained glass, and rotated at 1200 rpm for 60 seconds using a spin coater. The obtained glass was dried at 90 ° C. for 5 minutes to obtain a glass with a photocatalyst layer.

  The evaluation results of the obtained glass with a photocatalyst layer are shown in Table 1.

  From Table 1, it was found that Example 1 was superior to Comparative Example 1 in both photocatalytic activity and adhesion.

(Reference Example 1)
By applying a precoat liquid and a photocatalyst coating liquid to the surface of the ceiling material constituting the ceiling in the same manner as in Example 1, and drying after applying the photocatalyst coating liquid, a precoat layer having excellent adhesion to the surface of the ceiling material; A photocatalyst layer can be formed, which can reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor space by light irradiation by indoor lighting. Pathogens such as cocci and E. coli can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Furthermore, the surface of the ceiling material becomes hydrophilic, so that dirt can be easily wiped off, and further, charging can be prevented.

(Reference Example 2)
A precoat layer and a photocatalyst excellent in adhesion to the surface of the tile are applied to a tile constructed on an indoor wall surface by applying a precoat solution and a photocatalyst coating solution in the same manner as in Example 1, and drying after applying the photocatalyst coating solution. A layer can be formed, which can reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor space by light irradiation by indoor lighting. And pathogens such as Escherichia coli can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Furthermore, the surface of the tile becomes hydrophilic, so that dirt can be easily wiped off, and charging can be prevented.

(Reference Example 3)
The precoat liquid and photocatalyst coating liquid are applied to the indoor side surface of the window glass in the same manner as in Example 1, and the precoat layer and photocatalyst layer having excellent adhesion are formed on the glass surface by applying the photocatalyst coating liquid and drying it. It is possible to reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor spaces by light irradiation with indoor lighting, such as Staphylococcus aureus and Escherichia coli. Can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Further, the surface of the window glass becomes hydrophilic, so that dirt can be easily wiped off, and further charging can be prevented.

(Reference Example 4)
By applying the precoat liquid and the photocatalyst coating liquid to the wallpaper in the same manner as in Example 1, and drying after applying the photocatalyst coating liquid, a precoat layer and a photocatalyst layer having excellent adhesion to the wallpaper can be formed. By installing this wallpaper on the indoor wall, the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in the indoor space can be reduced by light irradiation by indoor lighting. Pathogens such as cocci and E. coli can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Furthermore, the surface of the wallpaper becomes hydrophilic, so that dirt can be easily wiped off, and charging can be prevented.

(Reference Example 5)
Applying a precoat liquid and a photocatalyst coating liquid to an indoor floor surface in the same manner as in Example 1, and drying after applying the photocatalyst coating liquid, thereby forming a precoat layer and a photocatalyst layer having excellent adhesion on the floor surface. This can reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor spaces by light irradiation with indoor lighting, and pathogens such as Staphylococcus aureus and Escherichia coli Can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Furthermore, the surface of the floor becomes hydrophilic, so that dirt can be easily wiped off and charging can be prevented.

(Reference Example 6)
A precoat solution and a photocatalyst coating solution are applied to the surface of an automobile interior material such as an instrument panel, an automobile seat, an automobile ceiling material, and an inside of an automobile glass in the same manner as in Example 1 to obtain a photocatalyst coating solution. By drying after coating, it is possible to form a precoat layer and a photocatalyst layer having excellent adhesion on the surface of these automobile interior materials, whereby volatile organic substances (for example, formaldehyde) in the vehicle interior space by light irradiation by vehicle interior lighting. , Acetaldehyde, acetone, toluene, etc.) and malodorous substances can be reduced, pathogens such as Staphylococcus aureus and Escherichia coli can be killed, viruses such as influenza virus, mite allergen and cedar pollen allergen Allergens such as these can also be rendered harmless. Furthermore, the surface of the automobile interior material becomes hydrophilic, so that dirt can be easily wiped off, and charging can be prevented.

(Reference Example 7)
Applying a precoat liquid and a photocatalyst coating liquid to the surface of the air conditioner in the same manner as in Example 1, and drying after applying the photocatalyst coating liquid, thereby forming a precoat layer and a photocatalyst layer having excellent adhesion on the surface of the air conditioner. This can reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor spaces by light irradiation with indoor lighting, and pathogens such as Staphylococcus aureus and Escherichia coli Can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Furthermore, the surface of the air conditioner becomes hydrophilic, so that dirt can be easily wiped off, and charging can be prevented.

(Reference Example 8)
Applying the precoat liquid and the photocatalyst coating liquid in the refrigerator cabinet in the same manner as in Example 1, and drying after applying the photocatalyst coating liquid, thereby forming a precoat layer and a photocatalyst layer having excellent adhesion in the refrigerator. This makes it possible to reduce the concentration of odorous substances such as ammonia and volatile organic substances (for example, ethylene) and ammonia in the refrigerator by irradiating light from the interior lighting or the light source in the refrigerator. Can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen can be rendered harmless. Furthermore, the surface in the refrigerator compartment becomes hydrophilic, so that dirt can be easily wiped off and charging can be prevented.

(Reference Example 9)
Apply the precoat liquid and photocatalyst coating liquid to the surface of the base material that is touched by an unspecified number of people, such as touch panels, train straps, elevator buttons, etc., and dry after applying the photocatalyst coating liquid as in Example 1. Thus, it is possible to form a precoat layer and a photocatalyst layer having excellent adhesion on the surface of the base material, and thereby volatile organic matter (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) in indoor space by light irradiation by indoor lighting. ) And malodorous substances can be reduced, pathogenic bacteria such as Staphylococcus aureus and Escherichia coli can be killed, and viruses such as influenza virus and allergens such as mite allergen and cedar pollen allergen are rendered harmless. You can also. Further, the surface of the base material becomes hydrophilic, so that dirt can be easily wiped off, and charging can be prevented.

Claims (6)

The manufacturing method of the photocatalyst structure which has the following process (a) and (b).
(A) The process of apply | coating the precoat liquid containing a metal alkoxide compound on a base material, and forming a precoat layer.
(B) A step of forming a photocatalyst layer by applying a photocatalyst coating solution on the precoat layer before the hydrolysis reaction or polycondensation reaction of the metal alkoxide compound is completed.   The method for producing a photocatalyst structure according to claim 1, wherein the precoat liquid further contains an inorganic layered compound.   The method for producing a photocatalyst structure according to claim 1 or 2, wherein the photocatalyst coating liquid contains at least photocatalyst particles and spherical particles having a particle diameter of 100 nm to 1 µm.   The method for producing a photocatalyst structure according to claim 3, wherein the content of the spherical particles is 5 to 65 parts by mass with respect to 100 parts by mass of the total solid content in the photocatalyst coating liquid.   The photocatalyst functional product which has the photocatalyst structure obtained by the method in any one of Claims 1-4 in at least one part of the base-material surface.   The photocatalytic functional product according to claim 5, wherein the substrate is a wallpaper or a film.