JP2010270543A - Product with photocatalytic body layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that a photocatalytic body layer including titanium oxide particles and tungsten oxide particles is colored blue, and therefore to solve such a significant problem that the coloring become conspicuous when such a photocatalytic body layer is formed on the surface of a non-black product, as the design is important in a wall paper, in particular. <P>SOLUTION: A product with the photocatalytic body layer includes a non-black product, an underlayer formed on the surface of the non-black product, and the photocatalytic body layer which includes at least photocatalyst titanium oxide particles and photocatalyst tungsten oxide particles, and is formed on the surface of the underlayer. The underlayer is obtained by applying a precoating liquid prepared by dissolving an iron compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a product with a photocatalyst layer.

  When a semiconductor is irradiated with light having energy greater than or equal to the band gap, electrons in the valence band are excited by the conductor and holes are generated in the valence band. The holes generated in this way 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 that can exhibit such a photocatalytic action is called a photocatalyst. Examples of such a photocatalyst include titanium oxide particles and tungsten oxide particles, and using them in contact with each other is known to improve photocatalytic action due to a synergistic effect in photoexcitation [Patent Document] 1].

  Therefore, a photocatalyst layer can be formed by applying a photocatalyst dispersion liquid composed of titanium oxide particles and tungsten oxide particles on the surface of the product indoors. The use of the product with the photocatalyst layer formed indoors can be expected to prevent malodor.

Japanese Patent Laid-Open No. 2003-265954

  However, the photocatalyst layer composed of such titanium oxide particles and tungsten oxide particles has a problem of being colored blue. For this reason, the formation and coloring of such a photocatalyst layer on the surface of a non-black product is conspicuous, and particularly for wallpaper, it has become a prominent problem because emphasis is placed on design.

  Therefore, as a result of intensive studies to solve the coloring problem when the photocatalyst layer is formed on the non-black product, the present inventors have completed the present invention.

  That is, the present invention relates to a photocatalyst layer comprising at least a non-black product, a base layer formed on the surface of the non-black product, and photocatalytic titanium oxide particles and photocatalytic tungsten oxide particles formed on the surface of the base layer. A product with a photocatalyst layer, wherein the underlayer is obtained by applying a precoat solution in which an iron compound is dissolved.

  According to the present invention, the photocatalyst is oxidized by applying a liquid obtained by dissolving the iron compound of the photocatalyst layer containing the iron compound to the surface of the non-black product, and applying the photocatalyst layer on the surface. Despite being composed of titanium particles and photocatalytic tungsten oxide particles, the problem that non-black products are colored blue hardly occurs.

(Product with photocatalyst layer)
The product with a photocatalyst layer of the present invention is a product with a photocatalyst layer composed of a base layer and a photocatalyst layer, and is obtained by applying a precoat liquid to the surface of a non-black product. It is a feature.

(Non-black product)
The non-black product constituting the product with a photocatalyst layer of the present invention is not particularly limited as long as the formed underlayer and photocatalyst layer can be retained. For example, ceiling material, tile, glass, wallpaper, wall material, floor Building materials such as automotive instrument panels, automotive seats, automotive interior materials such as automotive ceiling materials, and textile products such as clothing and curtains, particularly suitable for wallpaper.
Examples of the wallpaper include those containing ethylene-vinyl acetate copolymer resin, vinyl chloride resin, ethylene-methacrylic acid copolymer resin, ethylene-methyl methacrylate copolymer resin, acrylic resin and the like.
Here, the non-black system in the present invention may have any hue or saturation, and the lightness (L ^* ) in the L ^* a ^* b ^* display system defined by the International Commission on Illumination (Commission International de l'Eclairage). Means more than 20 colors. In the present invention, the non-black product preferably has a lightness of 50 or more, and more preferably a white color (light color) with a lightness of 80 or more.

(Underlayer)
The underlayer constituting the product with a photocatalyst layer of the present invention is obtained by applying a precoat solution for dissolving an iron compound to the surface of a non-black product. The precoat liquid can be applied by a printing method, a sheet forming method, a spray spraying method, a dip coating method, a spin coating method, a bar coating method, or the like. As drying conditions after application of the precoat liquid, the drying pressure is usually 0.008 to 0.12 MPa, preferably 0.009 to 0.11 MPa, and the drying temperature is usually 0 to 120 ° C., preferably 60 to It is 100 degreeC and drying time is 1 to 20 minutes normally.

(Precoat liquid)
The precoat liquid used in the present invention is a liquid for dissolving an iron compound, and the iron compound is dissolved in a solvent.
The iron compound is not particularly limited as long as it is an iron compound that can be dissolved in a solvent. For example, iron nitrate, iron chloride, iron bromide, iron iodide, iron sulfate, iron oxalate, iron citrate, benzoic acid Examples include iron, iron tartrate, iron stearate, and iron carbonate. These compounds may be used alone or in combination of two or more.
Content of the iron compound of a precoat liquid is 0.01-0.1 mass part normally in 100 weight part of precoat liquid in conversion of a metal atom, Preferably it is 0.03-0.07 mass part.
The solvent is not particularly limited as long as the iron compound can be dissolved. As the solvent used for the precoat liquid, a water-soluble organic solvent, water, or a mixed medium of water and a water-soluble organic solvent 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. Moreover, when using the mixed medium of a water-soluble organic solvent and water, it is preferable that content of the water in a mixed medium is 40 weight% or less with respect to a water-soluble organic solvent. As the water-soluble alcohol, ethanol is usually used.
The precoat liquid used in the present invention may be a fluid liquid, or a sol or gel.

In addition to the iron compound, the precoat liquid is, for example, one or more silicon alkoxides selected from the group consisting of a solvent, a zirconium compound, a compound represented by the following formula (1), and a compound represented by the above formula (2). It is preferable to use those containing
The liquid in which the iron compound is dissolved becomes an underlayer for forming a photocatalyst layer after coating.
Si (OR) ₄ (1)
[Wherein, four R's are independently of each other represented by the formula (1-1)
C _k H _{2k + 1} (1-1)
(In the formula, k represents a natural number.)
The substituent shown by these is shown. ]
And a compound of formula (2)
R ¹ _n Si (OR ² ) _4-n (2)
[Wherein, R ¹ and R ² are each independently of the formula (2-1)
C _m H _{2m + 1} (2-1)
(In the formula, m represents a natural number.)
N represents a natural number of 1 to 3, respectively. ]

(Zirconium compound)
Specific examples of zirconium compounds include zirconium oxalate, zirconium hydroxide, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, zirconium sulfate, zirconium acetate, zirconium carbonate ammonium, potassium zirconium carbonate, sodium zirconium phosphate, zirconium propionate, zirconium metal An alkoxide etc. are mentioned. 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. Preferably, zirconium oxalate is used.
The method for producing zirconium oxalate preferably used in the present invention is obtained by dispersing zirconium hydroxide in an aqueous oxalic acid solution so that the molar ratio of oxalic acid / zirconium is 1.2 to 3 and heating as necessary. be able to. When the molar ratio is less than 1.2, it is difficult to obtain the target zirconium oxalate, and when it exceeds 3, the acidity of the oxalic acid aqueous solution becomes strong and handling becomes difficult.
Zirconium compounds may be used alone or in combination of two or more. It is preferable that the content of the zirconium compound in terms of oxide (ZrO ₂ ) is 5 to 40 parts by weight in 100 parts by weight of the total amount in terms of oxide of the silicon alkoxide (SiO ₂ ).

(Silicon alkoxide)
Examples of the silicon alkoxide include one or more silicon alkoxides selected from the group consisting of the compound represented by the formula (1) and the compound represented by the formula (2).
Specifically, k in the formula (1-1) includes tetramethoxysilane or tetraethoxysilane in which 1 or 2 is used, and it is particularly preferable to use tetraethoxysilane.
Further, m in the formula (2-1) is preferably 1 to 4, and particularly preferably diethoxydimethylsilane.
Further, the silicon alkoxide is preferably used containing a compound represented by the formula (1) and a compound represented by the formula (2), and the content ratio thereof is 100: 0 to 90 in terms of oxide. : 10 or 75:25 to 60:40 is preferable.

(Preparation solution preparation)
The precoat liquid used in the present invention can be obtained, for example, by adding the silicon alkoxide to a solvent used for the precoat liquid and adding the iron compound and the zirconium compound thereto. These steps may be performed while stirring as necessary, or may be performed while heating.

(Photocatalyst layer)
The photocatalyst layer constituting the product with a photocatalyst layer of the present invention is formed on the surface of the underlayer and has at least photocatalytic titanium oxide particles and photocatalytic tungsten oxide particles. It can be formed by applying a photocatalyst dispersion liquid to the underlayer and drying it.

(Photocatalyst dispersion)
The photocatalyst dispersion liquid preferably contains at least particulate photocatalytic titanium oxide particles and photocatalytic tungsten oxide particles, and further contains an electron-withdrawing substance or a precursor thereof, and various known types within a range not impairing the effects of the present invention. The additive may be included.

(Photocatalytic titanium oxide particles)
Titanium oxide photocatalyst particles composing the photocatalyst layer of the present invention is not particularly limited as long as it is particulate titanium oxide that shows photocatalytic activity, for example it is a metatitanic acid particles or titanium dioxide (TiO _2), the crystalline form Are anatase type, brookite type or rutile type. In addition, a photocatalytic titanium oxide particle may be used independently and may use 2 or more types together.

  Metatitanic acid particles can be obtained, for example, by a method in which an aqueous solution of titanium sulfate is heated and hydrolyzed.

  The titanium dioxide particles are obtained, for example, by (i) a method in which a base is added to this solution without heating an aqueous solution of titanyl sulfate or titanium chloride to obtain a precipitate, and the obtained precipitate is calcined. An acidic aqueous solution or a basic aqueous solution is added to obtain a precipitate, and the obtained precipitate is fired. (Iii) A metatitanic acid is fired. The titanium dioxide particles obtained by these methods can be made into a desired crystal type such as anatase type, brookite type or rutile type by adjusting the baking temperature and baking time when baking.

  In addition to the above, the photocatalytic titanium oxide particles constituting the photocatalyst layer in the present invention include JP 2001-72419 A, JP 2001-190953 A, JP 2001-316116 A, and JP 2001-2001 A. 322816, JP2002-29749, JP200297019, WO01 / 10552 pamphlet, JP2001-212457, JP2002239395), WO03 / 080244 pamphlet, WO02 / 053501 pamphlet. JP 2007-69093 A, Chemistry Letters, Vol. 32, No. 2, P.196-197 (2003), Chemistry Letters, Vol. 32, No. 4, P.364-365 (2003), Chemistry Titanium oxide particles described in Letters, Vol. 32, No. 8, P. 772-773 (2003), Chem. Mater., 17, P. 1548-1552 (2005), etc. may be used. JP 2001-278625 A, JP 2001-278626 A, JP 2001-278627 A, JP 2001-302241 A, JP 2001-335321 A, JP 2001-354422 A, Titanium oxide particles obtained by the methods described in JP 2002-29750 A, JP 2002-47012 A, JP 2002-60221 A, JP 2002-193618 A, JP 2002-249319 A, etc. Can also be used.

  The particle diameter of the titanium oxide particles 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 titanium oxide particles is not particularly limited, from the viewpoint of photocatalytic activity, usually 100 to 500 m ² / g, preferably from 300~400m ² / g.

(Photocatalytic tungsten oxide particles)
The photocatalytic tungsten oxide particles constituting the photocatalyst layer in the present invention are particulate tungsten oxides exhibiting a photocatalytic action, and are not particularly limited as long as the valence of tungsten is 6. However, for example, tungsten trioxide (WO ₃ ) Particles. The photocatalytic tungsten oxide particles may be used alone or in combination of two or more.
The tungsten trioxide particles are obtained by, for example, (i) a method in which tungstic acid is obtained as a precipitate by adding an acid to an aqueous solution of tungstate, and the obtained tungstic acid is fired. (Ii) ammonium metatungstate, para It can be obtained by a method of thermally decomposing by heating ammonium tungstate.
The particle diameter of the tungsten oxide particles is not particularly limited, but from the viewpoint of photocatalysis, the average dispersed particle diameter is usually 50 to 200 nm, preferably 80 to 130 nm.
BET specific surface area of the tungsten oxide particles 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.

(Ratio of photocatalytic titanium oxide particles to photocatalytic tungsten oxide particles)
In the photocatalyst dispersion liquid, the ratio of the photocatalytic titanium oxide particles to the photocatalytic tungsten oxide particles (photocatalytic titanium oxide particles: photocatalytic tungsten oxide particles) is usually 1: 4 to 4: 1, preferably 2: 3 to 3: 2.

(Photocatalyst dispersion medium)
The photocatalyst dispersion medium constituting the photocatalyst dispersion liquid is not particularly limited as long as the particulate photocatalyst can be dispersed. Usually, an aqueous solvent containing water as a main component is used. Specifically, water alone or a mixed solvent of water and a water-soluble organic solvent may be used. When a mixed medium of water and a water-soluble organic solvent is used, the content of water is preferably 50% by weight or more. 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.
Moreover, you may contain a well-known dispersing agent.

(Dispersant)
Examples of the dispersant constituting the photocatalyst dispersion medium include other carboxylic acids such as dicarboxylic acid and tricarboxylic acid, and phosphoric acid (salt). Examples of the dicarboxylic acid include succinic acid, and examples of the tricarboxylic acid include citric acid. A free acid may be used as the polyvalent carboxylic acid and phosphoric acid, and a salt may be used. Examples of the salt include ammonium salts. Preferred examples of the dispersant include oxalic acid, ammonium oxalate, and ammonium dihydrogen phosphate.
The amount of the dispersant used is, for example, usually 0.001 mol times or more, preferably 0.02 mol times or more with respect to the photocatalyst titanium oxide in terms of TiO ₂ , and is usually 0 in terms of economy. .5 mole times or less, preferably 0.3 mole times or less.

(Preparation of photocatalyst dispersion)
In the photocatalyst dispersion, the photocatalyst is added to the photocatalyst dispersion medium. The content of the photocatalyst dispersion medium is usually 5 to 200 times by weight, preferably 10 to 100 times by weight with respect to the photocatalyst.
When mixing photocatalyst titanium oxide and photocatalyst tungsten oxide as a photocatalyst, after dispersing photocatalyst titanium oxide in the photocatalyst dispersion medium in the presence of a dispersant, further dispersing treatment is performed in the same manner. You may mix with the dispersion liquid of the photocatalyst tungsten oxide which performed the process. The dispersion treatment can be performed, for example, by an ordinary method using a medium stirring type disperser.

(Electron-withdrawing substance or its precursor)
The electron-withdrawing substance constituting the photocatalyst dispersion liquid is a compound that is supported on the surface of the photocatalyst body and can exhibit electron-withdrawing properties, and the precursor of the electron-withdrawing substance constituting the photocatalyst dispersion liquid is A compound that can transition to an electron-withdrawing substance on the surface of the photocatalyst (for example, a compound that can be reduced to an electron-withdrawing substance by light irradiation). The addition of the electron-withdrawing substance or its precursor may be performed on the titanium oxide dispersion liquid or after mixing both dispersion liquids. Here, from the viewpoint of obtaining a high photocatalytic action, it is preferably added to the tungsten oxide dispersion. When an electron-withdrawing substance is supported on the surface of the photocatalyst, recombination of electrons excited by the conductor with light irradiation and holes generated in the valence band is suppressed, and the photocatalytic action is further enhanced. it can.

When the electron-withdrawing substance precursor is added, light irradiation is preferably performed after the addition. The light to be irradiated is not particularly limited as long as the light has energy higher than the band gap of the photocatalyst. By irradiating with light, the precursor is reduced by the electrons generated by photoexcitation to become an electron-withdrawing substance and is carried on the surface of the photocatalyst. In addition, although light irradiation may be performed with respect to a photocatalyst body dispersion liquid, you may perform after formation of a photocatalyst layer. More preferably, when a plurality of photocatalysts are mixed, it is preferably performed before mixing.
Furthermore, methanol, ethanol, oxalic acid, or the like can be added as a sacrificial agent before irradiation with light for the purpose of more efficiently supporting the electron-withdrawing substance.

  The electron withdrawing substance or its precursor contains one or more metal atoms selected from the group consisting of Cu, Pt, Au, Pd, Ag, Fe, Nb, Ru, Ir, Rh and Co. It is preferable that More preferably, it contains one or more metal atoms of Cu, Pt, Au and Pd. For example, the electron-withdrawing substance may be a metal made of the metal atom, or an oxide or hydroxide of these metals, and the precursor of the electron-withdrawing substance may be a metal made of the metal atom. Nitrates, sulfates, halides, organic acid salts, carbonates, phosphates, and the like.

Preferable specific examples of the electron-withdrawing substance include Cu, Pt, Au, and Pd metals. Moreover, as a preferable specific example of the precursor of an electron withdrawing substance, as a precursor containing Cu, copper nitrate [Cu (NO ₃ ) ₂ ], copper sulfate [CuSO ₄ ], copper chloride [CuCl ₂ , CuCl], Copper bromide [CuBr ₂ , CuBr], copper iodide [CuI], copper iodate [CuI ₂ O ₆ ], ammonium chloride [Cu (NH ₄ ) ₂ Cl ₄ ], copper oxychloride [Cu ₂ Cl (OH) ) ₃ ], copper acetate [CH ₃ COOCu, (CH ₃ COO) ₂ Cu], copper formate [(HCOO) ₂ Cu], copper carbonate [CuCO ₃ ), copper oxalate [CuC ₂ O ₄ ], copper citrate [ Cu ₂ C ₆ H ₄ O ₇ ], copper phosphate [CuPO ₄ ]; as a precursor containing Pt, platinum chloride [PtCl ₂ , PtCl ₄ ], platinum bromide [PtBr ₂ , PtBr ₄ ], platinum iodide [PtI _2, PtI _4], potassium platinum chloride [K ₂ (PtCl _4)], hexa Rollo chloroplatinic acid [H ₂ PtCl _6], platinum sulfite _{[H 3 Pt (SO 3) 2} OH ], platinum oxide [PtO _2], tetraammine platinum chloride [Pt (NH _{3) 4} Cl _2], bicarbonate tetraammineplatinum [ C ₂ H ₁₄ N ₄ O ₆ Pt], tetraammineplatinum hydrogen phosphate [Pt (NH ₃ ) ₄ HPO ₄ ], tetraammineplatinum platinum [Pt (NH ₃ ) ₄ (OH) ₂ ], tetraammineplatinum nitrate [Pt ( NO ₃ ) ₂ (NH ₃ ) ₄ ], tetraammine platinum tetrachloro platinum [(Pt (NH ₃ ) ₄ ) (PtCl ₄ )], dinitrodiamine platinum [(Pt (NH ₃ ) ₂ (NO ₂ ) ₂ )] As a precursor containing Au, gold chloride [AuCl], gold bromide [AuBr], gold iodide [AuI], gold hydroxide [Au (OH) ₂ ], tetrachloroauric acid [HAuCl ₄ ], tetrachloro; Potassium goldate [KAuCl ₄ ], tetrabromoauric acid For example, palladium [KAuBr ₄ ], gold oxide [Au ₂ O ₃ ]; Pd-containing precursors such as palladium acetate [(CH ₃ COO) ₂ Pd], palladium chloride [PdCl ₂ ], palladium bromide [PdBr ₂ ] ], Palladium iodide [PdI ₂ ], palladium hydroxide [Pd (OH) ₂ ], palladium nitrate [Pd (NO ₃ ) ₂ ], palladium oxide [PdO], palladium sulfate [PdSO ₄ ], potassium tetrachloropalladate [K ₂ (PdCl ₄ )], potassium tetrabromopalladate [K ₂ (PdBr ₄ )], tetraammine palladium chloride [Pd (NH ₃ ) ₄ Cl ₂ ], tetraammine palladium bromide [Pd (NH ₃ ) ₄ Br ₂ ], tetraamminepalladium nitrate _{[Pd (NH 3) 4 (NO} 3) 2 ], tetraammine palladium tetraamine Mi Palladium tetra ammine palladium chloride _{[(Pd (NH 3) 4)} (PdCl 4) ], ammonium tetrachloropalladate _{[(NH 4)} 2 PdCl _4] are; like, respectively. In addition, an electron withdrawing substance or its precursor may each be used independently, and may use 2 or more types together. Needless to say, one or more electron-withdrawing substances and one or more precursors may be used in combination.

  When the electron-withdrawing substance or its precursor is also contained, the content is usually 0.005 to 0.6 parts by weight with respect to 100 parts by weight of the total amount of titanium oxide and tungsten oxide in terms of metal atoms. The amount is preferably 0.01 to 0.4 parts by weight. If the electron-withdrawing substance or its precursor is less than 0.005 parts by weight, the effect of improving the photocatalytic activity by the electron-withdrawing substance may not be sufficiently obtained, while if it exceeds 0.6 parts by weight, On the contrary, the photocatalytic action may be reduced.

(Additive)
As an additive which comprises a photocatalyst body dispersion liquid, what is added in order to improve a photocatalytic action is mentioned, for example. Specific examples of such additives for improving the photocatalytic effect include silicon compounds such as amorphous silica, silica sol, water glass, and organopolysiloxane; amorphous alumina, alumina sol, aluminum hydroxide, and the like. Aluminosilicates such as zeolite and kaolinite; alkaline earth metal oxides such as magnesium oxide, calcium oxide, strontium oxide, barium oxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide Or alkali metal hydroxides: calcium phosphate, molecular sieve, activated carbon, polycondensate of organic polysiloxane compound, phosphate, fluoropolymer, silicone polymer, acrylic resin, polyester resin, melamine resin, urethane resin, alkyd Fats; and the like.
Further, as the additive, a binder or the like for holding the photocatalyst (photocatalytic titanium oxide and photocatalytic titanium oxide) more firmly on the surface of the substrate when the photocatalyst dispersion liquid is applied to the substrate surface is used. (For example, JP-A-8-67835, JP-A-9-25437, JP-A-10-183061, JP-A-10-183062, JP-A-10-168349, JP-A-10-225658. Publication No. 11-1620, No. 11-1661, No. 2004-059686, No. 2004-107381, No. 2004-256590, No. 2004-359902. JP, 2005-113028, JP, 2005-230661, JP, 2007-16 See No. 824).
Each additive may be used alone or in combination of two or more.

(Application and drying of photocatalyst dispersion)
The photocatalyst dispersion liquid thus obtained is applied to a non-black product and dried. The coating can be performed by a printing method, a sheet forming method, a spray spraying method, a dip coating method, a spin coating method, a bar coating method, or the like. As drying conditions, the drying pressure is usually 0.008 to 0.12 MPa, preferably 0.009 to 0.11 MPa, the drying temperature is usually 0 to 120 ° C., preferably 60 to 100 ° C., The drying time is usually 1 to 20 minutes.

(wallpaper)
The wallpaper is usually made of a base sheet, and a resin layer containing a capsule foaming agent that has been foamed may be formed on one surface thereof.
The base sheet is a general paper such as a flame retardant paper for a wallpaper (a pulp-based sheet, a sheet treated with a flame retardant such as guanidine sulfamate or guanidine phosphate), aluminum hydroxide paper, or inorganic paper.
The resin layer is a layer made of resin. Examples of the resin include ethylene-vinyl acetate copolymer resin, vinyl chloride resin, ethylene-methacrylic acid copolymer resin, ethylene-methyl methacrylate copolymer resin, and acrylic resin. The resin layer may contain a capsule foaming agent. The capsule foaming agent is a microsphere having a particle size of 10 to 30 μm in which a low boiling point organic solvent is encapsulated with a film of a thermoplastic polymer organic material. As the coating material, vinylidene chloride / acrylonitrile copolymer, acrylonitrile / acrylic copolymer, nitrile copolymer, etc. are used, and as low boiling point organic solvents, there are isobutane, butane, pentane, isopentane, hexane, etc. . Here, the foaming treatment may be performed by any method as long as the capsule foaming agent foams, but is usually foamed by heating. As conditions for the foaming treatment, the temperature is usually 100 to 250 ° C., preferably 120 to 200 ° C., the pressure is usually 0.008 to 0.12 MPa, preferably 0.009 to 0.11 MPa, and the time Is usually 1 to 300 seconds. The wallpaper may be embossed as necessary. After foaming, the capsule foaming agent becomes spherical with a particle size of 30 to 200 μm.

  The product with a photocatalyst layer obtained in this way is only subjected to light from a visible light source such as a fluorescent lamp or a sodium lamp by appropriately selecting the photocatalyst despite being foamed. High catalytic activity by light irradiation in an indoor environment. Therefore, when this wallpaper is applied to, for example, hospital ceiling materials, tiles, and glass, and dried, odorous odors such as volatile organic substances such as formaldehyde and acetaldehyde, aldehydes, mercaptans, and ammonia are emitted by light irradiation from indoor lighting. The concentration of substances and nitrogen oxides can be reduced, and pathogenic bacteria such as Staphylococcus aureus and Escherichia coli can be decomposed and removed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

  In addition, about the measurement of each physical property in an Example and a comparative example, and the evaluation of the photocatalytic activity, it performed 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.).

<Average dispersed particle size>
The particle size distribution was measured using a sub-micron particle size distribution measuring device (“N4Plus” manufactured by Coulter, Inc.), and the result obtained by performing the monodisperse mode analysis automatically with the software attached to this device was used as the average dispersed particle size nm).

<Lightness evaluation of products with photocatalyst layer>
Using a color difference meter (trade name “Z-300A”, manufactured by Nippon Denshoku Industries Co., Ltd.), JIS Z-8729
Obtained according to 1994.

<Creation of product with photocatalyst layer>
A precoat solution was applied with a bar coater (No. 3) to a wallpaper (7 cm × 15 cm) made of an ethylene-vinyl acetate copolymer having a lightness (L *) of 94.8, dried at 90 ° C. for 15 minutes, The photocatalyst dispersion liquid was similarly applied to the surface with a bar coater (No. 6) and dried at 90 ° C. for 15 minutes. Thereafter, the product was foamed by drying at 180 ° C. for 30 seconds to prepare a product with a photocatalyst layer.

<Coloring evaluation of products with photocatalyst layer>

Whether the product with photocatalyst layer is colored blue by cutting out the product with photocatalyst layer prepared in step 5cm x 2.5cm, irradiating with UV light from black light so that the UV intensity becomes 2mW / cm ² Observed with the naked eye.

<Evaluation of photocatalytic activity>
A product with a photocatalyst layer to be measured was cut into 5 cm × 10 cm and irradiated with ultraviolet light from a black light for 16 hours so that the ultraviolet intensity was ² mW / cm ^2, 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 5 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. 5 L of mixed gas was sealed, and 10 mL of nitrogen gas containing acetaldehyde at 1% by volume was sealed therein, and the mixture was kept in the dark at room temperature for 1 hour. Thereby, the density | concentration of the enclosed acetaldehyde will be 20 ppm. After that, using black light as a light source, the intensity of ultraviolet light near the sample near the sample for measurement was 1 mW / cm ² (the UV intensity meter “UVR-2” manufactured by Topcon Corp. and the light receiving unit “UD-36” manufactured by the same company Acetaldehyde was decomposed by irradiating with ultraviolet light from the outside of the gas bag so that the measurement was performed. The gas in the gas bag was sampled every 1.5 hours after the light irradiation of the black light was started, and the concentration of acetaldehyde was measured with a gas chromatograph (“GC-14A” manufactured by Shimadzu Corporation).

(Production Example 1-Preparation of zirconium oxalate)
100 g of zirconium hydroxide (31 g in terms of ZrO ₂ ) was added to 100 g of water and stirred well to obtain a dispersion. Next, as the first addition of oxalic acid, 31.7 g of oxalic acid dihydrate (oxalic acid / Zr molar ratio = 1.0) was added to the dispersion and heated at 90 ° C. for 15 minutes. Next, as the second addition of oxalic acid, 15.8 g of oxalic acid dihydrate (oxalic acid / Zr molar ratio = 0.5) was added to the dispersion and heated at 90 ° C. for 15 minutes to obtain a zirconium oxalate dispersion. . Thereafter, water was added to adjust the concentration in terms of ZrO ₂ to 9.8% by weight.

(Production Example 2-Preparation of titanium oxide particle dispersion)
20.7 g of ammonium dihydrogen phosphate (Wako Special Grade Reagent) was dissolved in 5.39 kg of water, and the resulting aqueous solution of ammonium dihydrogen phosphate in the solid solution of metatitanic acid (cake) obtained by thermal hydrolysis of titanyl sulfate. ) (Solid content concentration of 46.2 mass% as TiO ₂ ) 1.49 kg was mixed. At this time, the amount of ammonium dihydrogen phosphate was 0.02 mol with respect to 1 mol of metatitanic acid. The obtained mixture was subjected to a dispersion treatment under the following conditions using a medium stirring type disperser (“Ultra Apex Mill UAM-1” manufactured by Kotobuki Giken Co., Ltd.) to obtain a titanium oxide particle dispersion.
Medium: zirconia beads having a diameter of 0.05 mm Processing temperature: 20 ° C
Processing time: about 76 minutes Rotation speed: 3430 rpm
Flow rate: 0.25L / min

  The average dispersed particle diameter of the titanium oxide particles in the obtained titanium oxide particle dispersion was 96 nm. A part of the mixture before the dispersion treatment and the dispersion after the dispersion treatment were vacuum-dried to obtain a solid content, and the X-ray diffraction spectrum of each solid content was measured and compared. It was anatase type, and no change in crystal form due to dispersion treatment was observed.

(Production Example 3-Preparation of tungsten oxide particle dispersion)
1 kg of particulate tungsten oxide powder (manufactured by Nippon Inorganic Chemical Co., Ltd.) was added to 4 kg of ion-exchanged water and mixed to obtain a mixture. This mixture was subjected to dispersion treatment under the following conditions using a medium agitating disperser (“Ultra Apex Mill UAM-1” manufactured by Kotobuki Giken Co., Ltd.) to obtain a tungsten oxide particle dispersion.
Dispersion medium: 1.85 kg of zirconia beads having a diameter of 0.05 mm
Stirring speed: peripheral speed 12.6 m / sec Flow rate: 0.25 L / min Total processing time: about 50 minutes

The average dispersed particle diameter of the tungsten oxide particles in the obtained tungsten oxide particle dispersion was 118 nm. Moreover, when a part of this dispersion was vacuum-dried to obtain a solid content, the BET specific surface area of the obtained solid content was 40 m ² / g. Similarly, the mixture before the dispersion treatment is also vacuum-dried to obtain a solid content, and X-ray diffraction spectra are respectively measured for the solid content of the mixture before the dispersion treatment and the solid content of the dispersion after the dispersion treatment. As a result of comparison, the crystal form of both was WO ₃ , and no change in crystal form due to dispersion treatment was observed. At this time, when the obtained dispersion was stored at 20 ° C. for 3 hours, no solid-liquid separation was observed during storage.

In this tungsten oxide particle dispersion, an aqueous solution of hexachloroplatinic acid (H ₂ PtCl ₆ ) is added in an amount of 0.12 parts by mass (0.12% by mass) with respect to 100 parts by mass of tungsten oxide particles in terms of platinum atoms. ) To obtain a hexachloroplatinic acid-containing tungsten oxide particle dispersion as a raw material dispersion. The solid content (amount of tungsten oxide particles) contained in 100 parts by mass of this dispersion was 10 parts by mass (solid content concentration 10% by mass).

  Next, 500 g of the hexachloroplatinic acid-containing tungsten oxide particle dispersion liquid at a rate of 1 liter per minute was obtained using a light irradiation device comprising a glass tube (inner diameter: 37 mm, height: 360 mm) equipped with an underwater germicidal lamp [“GLD15MQ” manufactured by Sankyo Electric Co., Ltd.]. While circulating, irradiate the hexachloroplatinum tri-containing tungsten oxide particle dispersion with light (ultraviolet rays) for 1 hour, add methanol so that its concentration becomes 1.1% by mass of the total solvent, and circulate light ( UV light was irradiated for 1 hour to obtain a platinum-containing tungsten oxide particle dispersion.

(Production Example 4-Preparation of photocatalyst dispersion)
In the titanium oxide particle dispersion obtained in Production Example 2 and the platinum-containing tungsten oxide particle dispersion obtained in Production Example 3, the ratio of titanium oxide particles to tungsten oxide particles is 1: 1 (mass ratio). (Thus, the platinum content in the dispersion is 0.06 parts by mass (0.002 parts per 100 parts by mass of titanium oxide particles and tungsten oxide particles in terms of platinum atoms).
The mixture of titanium oxide particle dispersion and platinum-containing tungsten oxide particle dispersion was obtained. Further, the solid content (total amount of titanium oxide and tungsten oxide) contained in 100 parts by weight of this photocatalyst dispersion liquid was 5 parts by weight (solid content concentration 5% by weight).
When the obtained photocatalyst dispersion liquid was stored at 20 ° C. for 3 hours, no solid-liquid separation was observed during storage.

Example 1
6 g of ethanol was added to 3.02 g of water, and 6.94 g of high purity ethyl silicate (manufactured by Tama Chemical) was added. 4.04 g of zirconium oxalate (ZrO ₂ equivalent concentration: 9.8 wt%) obtained in Production Example 1 was added thereto. 5g up then from the resultant solution, to obtain a pre-coat liquid thereto iron nitrate nonahydrate _{(Fe (NO 3) 3 ·} 9H 2 O) 0.017g added. The content of zirconium oxalate with respect to 100 parts by weight of ethyl silicate in terms of oxide was 20 parts by weight. In 100 parts by weight of the precoat solution, the content of iron was 0.047 parts by weight in terms of metal atoms.

The precoat liquid obtained here is applied to form a base layer, the photocatalyst dispersion liquid obtained in Production Example 4 is applied to form a photocatalyst body layer, and then subjected to foaming treatment to provide a photocatalyst body layer. Created a product. In this wallpaper, black light is used as the light source, and the intensity of the ultraviolet light near the sample for measurement is ² mW / cm ² (the UV intensity meter “UVR-2” manufactured by Topcon Co., Ltd. ) Was measured for 20 minutes, and no discoloration was observed on the wallpaper with the naked eye. When the photocatalytic activity of this wallpaper was measured, the concentration of acetaldehyde after irradiation with black light for 1.5 h was 0.1 ppm.

Comparative Example 1
In Example 1, a liquid was obtained without adding iron nitrate. Thereafter, a product with a photocatalyst layer was prepared in the same manner as in Example 1. In this wallpaper, black light is used as the light source, and the intensity of the ultraviolet light near the sample for measurement is ² mW / cm ² (the UV intensity meter “UVR-2” manufactured by Topcon Co., Ltd. ) Was measured for 20 minutes, and it was found that the wallpaper turned blue with the naked eye. When the photocatalytic activity of this wallpaper was measured, the concentration of acetaldehyde after irradiation with black light for 1.5 h was 0.1 ppm.

  It was found that when the precoat solution of Example 1 was used for forming the underlayer, it was possible to suppress the coloring of the wallpaper while maintaining the photocatalytic activity as compared with Comparative Example 1.

Claims (3)

An underlayer formed on the surface of a non-black product;
A photocatalyst layer-attached product comprising a photocatalyst body layer having at least photocatalytic titanium oxide particles and photocatalytic tungsten oxide particles formed on the surface of the underlayer,
A product with a photocatalyst layer, wherein the underlayer is obtained by applying a precoat solution for dissolving an iron compound on the surface of the non-black product. The precoat solution comprises a zirconium compound and a formula (1)
Si (OR) ₄ (1)
[Wherein, four R's are independently of each other represented by the formula (1-1)
C _k H _{2k + 1} (1-1)
(In the formula, k represents a natural number.)
The substituent shown by these is shown. ]
And a compound of formula (2)
R ¹ _n Si (OR ² ) _4-n (2)
[Wherein, R ¹ and R ² are each independently of the formula (2-1)
C _m H _{2m + 1} (2-1)
(In the formula, m represents a natural number.)
N represents a natural number of 1 to 3, respectively. ]
The product with a photocatalyst layer according to claim 1, comprising at least one silicon alkoxide selected from the group consisting of compounds represented by:   The product with a photocatalyst layer according to claim 1 or 2, wherein the non-black product is wallpaper.