Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/39—Photocatalytic properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/063—Titanium; Oxides or hydroxides thereof
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/02—Emulsion paints including aerosols
  • C09D5/024—Emulsion paints including aerosols characterised by the additives
  • C09D5/027—Dispersing agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/61—Additives non-macromolecular inorganic
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/65—Additives macromolecular
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
  • C08K2003/2237—Oxides; Hydroxides of metals of titanium
  • C08K2003/2241—Titanium dioxide
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/54—Aqueous solutions or dispersions

Definitions

• the present invention relates to a photocatalyst coating liquid for forming a photocatalyst coating film, a method for producing the same, and a photocatalyst body.
• a semiconductor When a semiconductor is irradiated with ultraviolet rays, electrons having a strong reducing action and holes having a strong oxidizing action are generated, and the molecular species in contact with the semiconductor are decomposed by the redox action. Such an action is called a photocatalytic action, and by utilizing this photocatalytic action, organic compounds and NOx in atmospheric substances can be decomposed.
• a photocatalytic semiconductor is called a photocatalyst, and it has been proposed to use the photocatalyst in various forms for the purpose of deodorization, gas treatment, water treatment, antibacterial action and antifouling, utilizing the characteristics of the photocatalyst. ing.
• the photocatalyst has a property of becoming hydrophilic upon irradiation with light, for example, has a property of repelling oily dirt.
• a solution containing a photocatalyst is used as a coating solution to be applied on a substrate or a coating film formed on the substrate, and is drip-proof, antifouling / antifogging, self-cleaning And imparting easy cleaning properties to the surface of a substrate or coating film.
• the coating film of the photocatalyst is formed by applying a coating liquid containing photocatalyst particles to the surface of the substrate and drying or baking at a low temperature as necessary.
• a binder is used to adhere and support the photocatalyst particles on the surface of the substrate.
• an organic polymer is used as the binder, there is a problem that the photocatalytic particles are oxidized by the photocatalytic action and the adhesion to the substrate surface is reduced.
• Patent Document 1 a method using a fluorine-based resin that is not easily oxidized
• Patent Document 2 a method using titanium peroxide for a binder
• the present invention can form a photocatalyst coating film having excellent photocatalytic properties without lowering the dispersibility of photocatalyst particles even when a fluorine resin or titanium peroxide is used as a binder.
• An object of the present invention is to provide a photocatalyst coating liquid and a method for producing the same.
• the photocatalyst coating liquid of the present invention contains at least one binder selected from photocatalyst particles, titanium peroxide and / or fluorine-based resin, a dispersant, and an aqueous medium. And at least a neutralized copolymer and / or polyphosphate comprising a hydrophobic monomer and an anionic group-containing monomer.
• the method for producing a photocatalyst coating liquid of the present invention is characterized in that photocatalyst particles and / or a binder are added to and mixed with a dispersant solution in which a dispersant is dissolved in an aqueous medium.
• the photocatalyst of the present invention is characterized in that it has a coating film formed on the surface using the photocatalyst coating liquid of the present invention.
• the dispersibility of the photocatalyst particles does not decrease, so that a photocatalytic coating film having excellent photocatalytic performance is formed. Is possible.
• the photocatalyst coating liquid of the present invention contains at least one binder selected from photocatalyst particles, titanium peroxide and a fluorine resin, a dispersant and an aqueous medium.
• a dispersant at least a hydrophobic monomer and an anionic property It contains a neutralized product of a copolymer comprising a group-containing monomer and / or a polyphosphate.
• the photocatalyst particles used in the present invention are particles of a compound that exhibits a photocatalytic action by ultraviolet rays or visible rays.
• a photocatalyst Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag .
• metal elements such as Au, Zn, Cd, Ga, In, Tl, Ge, Sn, Pb, Bi, La, Ce, nitride, sulfide, oxynitride, Examples thereof include oxysulfides, nitrofluorides, oxyfluorides, oxynitrofluorides, and the like.
• titanium oxide is particularly preferable.
• the titanium oxide here includes a small amount (for example, 1 mol% or less of Ti) doped with metal ions such as platinum, copper, iron or nitrogen or a small amount (for example, 1 mol% of Ti).
• metal ions such as platinum, copper, iron or nitrogen or a small amount (for example, 1 mol% of Ti).
• metal ions such as platinum, copper, iron or nitrogen
• a small amount for example, 1 mol% of Ti.
• metal ions such as platinum, copper, iron or nitrogen
• a small amount for example, 1 mol% of Ti
• those carrying other metal oxides are included.
• examples of titanium oxide include anatase type, rutile type, brookite type, and the like, and any of them can be used as photocatalyst particles.
• the titanium oxide particle shape can be used without any particular limitation, such as amorphous, spherical, cubic, plate-like, needle-like, rod-like, or spindle-
• the photocatalyst particles used in the present invention preferably have a primary particle diameter of 5 nm to 500 nm.
• photocatalyst particles having such a primary particle size for example, in the case of titanium oxide, trade names ST-01, ST-21, ST-31, ST-41, MPT-623, Sakai Chemical Industry Co., Ltd. manufactured by Ishihara Sangyo Co., Ltd.
• rod-shaped rutile titanium oxide nanoparticles having crystal faces (001) (110) (111) produced by subjecting a tetravalent titanium compound to hydrothermal treatment for 2 hours or more can also be used.
• the photocatalyst particles are 1 to 50% by weight, preferably 2 to 40% by weight of the entire photocatalyst coating liquid. If it is less than 1% by weight, it is difficult to obtain a photocatalytic action. On the other hand, if it exceeds 50% by weight, the viscosity of the coating solution becomes high and handling becomes difficult, and the stability over time decreases, and the photocatalyst particles easily aggregate.
• the dispersant used in the present invention contains at least a neutralized copolymer and / or polyphosphate composed of a hydrophobic monomer and an anionic group-containing monomer.
• the hydrophobic monomer in the neutralized product of the copolymer has a polymerizable double bond and has a lipophilic hydrocarbon group, aromatic ring group, or alicyclic group.
• Specific examples include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl (meth) acrylate, and isoamyl (meth) acrylate.
• anionic group-containing monomer examples include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, vinyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, etc. And sulfonic acid group-containing monomers and phosphoric acid group-containing monomers.
• carboxyl group-containing monomers are more preferred are acrylic acid, methacrylic acid, itaconic acid and maleic acid, and even more preferred is acrylic acid.
• a preferred copolymer is a copolymer containing styrene as a hydrophobic monomer and acrylic acid as an anionic group-containing monomer (hereinafter referred to as a styrene-acrylic acid copolymer). 1 or more types may be included.
• the styrene-acrylic acid copolymer has a weight average molecular weight (hereinafter abbreviated as MW) of 1,000 to 100,000, preferably 4,000 to 30,000.
• the acid value is 50 to 500, preferably 150 to 300.
• Jonkrill series As specific examples of this styrene-acrylic acid copolymer, the following Jonkrill series manufactured by BASF, high loss series manufactured by Seiko PMC, and ARUFON series manufactured by Toagosei Co., Ltd. can be used.
• Jonkrill series Jonkrill 67 (MW 12500, acid value 213) Jonkrill 678 (MW8500, acid value 215) Jonkrill 586 (MW4600, acid value 108) Jonkrill 611 (MW8100, acid value 53) Jonkrill 680 (MW4900, acid value 215) Jonkrill 682 (MW 1700, acid value 238) Jonkrill 683 (MW 8000, acid value 160) Jonkrill 690 (MW 16500, acid value 240) Jonkrill 52J (60% aqueous solution, MW 1700, acid value 238) Jonkrill 57J (37% aqueous solution, MW4900, acid value 215) Jonkrill 60J (34% aqueous solution, MW8500, acid value 215) Jon
• the concentration of the copolymer neutralized product used in the dispersant is 0.1 to 25% by weight, preferably 0.3 to 20% by weight, based on the total photocatalyst coating liquid. If the concentration of the dispersing agent is less than 0.1% by weight, the dispersibility of the photocatalyst particles tends to be reduced and aggregation tends to occur. If the concentration exceeds 25% by weight, the viscosity of the coating solution becomes high, handling becomes difficult, and the photocatalytic performance is also improved. It is because it does not improve.
• the copolymer neutralized product used in the dispersant may be a commercially available neutralized product, or a neutralized product obtained by neutralizing a carboxylic acid type dispersant with a basic substance.
• Basic substances used for neutralization include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, alkali metal hydroxides such as cesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, Alkali metal carbonates such as cesium carbonate; lithium metal carbonates such as lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, rubidium hydrogen carbonate, cesium hydrogen carbonate; lithium phosphate, sodium phosphate, potassium phosphate, Alkali metal phosphates such as rubidium phosphate and cesium phosphate; Borates of alkali metals such as lithium borate, sodium borate, potassium borate, rubidium borate, cesium borate; lithium silicate, silicic acid Sodium, potassium silicate, rub
• Potassium metal silicates alkaline metal acetates such as lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate; lithium citrate, sodium citrate, potassium citrate, rubidium citrate, cesium citrate, etc.
• Alkali metal citrate Alkali metal citrate; ammonia; methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, butylamine, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, dimethylethanolamine, methyldiethanolamine, amino Examples include amines such as methylpropanol, and one or more of these can be used.
• alkali metal hydroxides carbonates or bicarbonates
• potassium hydroxide sodium hydroxide and cesium hydroxide
• More preferred are potassium hydroxide and cesium hydroxide in that they are excellent in reducing the particle size of the photocatalyst particles.
• the basic substance used for neutralization is added in an amount equal to or greater than the equivalent amount of the anionic group determined from the acid value of the dispersant.
• the dispersant solution is added so that the pH is in the range of 7 to 10, preferably 7 to 9.
• the solid content of the basic substance is 0.01 to 10% by weight, preferably 0.03 to 5% by weight of the total photocatalyst coating liquid.
• the polyphosphate used for the dispersant in the present invention is an alkali metal salt of polyphosphoric acid such as pyrophosphoric acid, tripolyphosphoric acid, metaphosphoric acid, tetraphosphoric acid, hexaphosphoric acid, and for example, potassium polyphosphate or sodium polyphosphate is used. be able to.
• the concentration of the polyphosphate is 0.1 to 25% by weight, preferably 0.3 to 20% by weight, based on the total photocatalyst coating liquid. If the concentration of the dispersing agent is less than 0.1% by weight, the dispersibility of the photocatalyst particles tends to be reduced and aggregation tends to occur. If the concentration exceeds 25% by weight, the viscosity of the coating solution becomes high, handling becomes difficult, and the photocatalytic performance is also improved. It is because it does not improve.
• the mixing ratio of copolymer neutralized product and polyphosphate (copolymer neutralized product / polyphosphate) (Weight ratio of solid content) is 1/100 to 100/1, preferably 1/10 to 10/1. This is because if the ratio is smaller than 1/100, the effect of the combined use cannot be seen, and if it is larger than 100/1, the combined effect cannot be seen similarly.
• titanium peroxide and / or fluorine resin As the binder, titanium peroxide and / or fluorine resin is used. Titanium peroxide (peroxotitanic acid) is produced by treating titanium hydroxide produced by adding ammonia or alkali hydroxide to a titanium salt solution such as titanium tetrachloride with hydrogen peroxide. Obtained as a liquid in which ultrafine particles are dispersed.
• titanium peroxide for example, those described in Japanese Patent No. 2938376 of Saga Prefecture and Japanese Patent No. 3690864 of Tio Techno Co., Ltd. can be used.
• titanium peroxide and fluorine resin When titanium peroxide and fluorine resin are used in combination, the adhesion and acid resistance of the coating film are excellent.
• Fluorocarbon resins include polyvinylidene fluoride, polychloroethylene trifluoride, polytetrafluoroethylene, polytetrafluoroethylene-hexafluoropropylene copolymer, ethylene-polytetrafluoroethylene copolymer, ethylene-trichlorochloride.
• Crystalline fluorine resin such as fluorinated ethylene copolymer, ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer, amorphous fluororesin such as perfluorocyclopolymer, vinyl ether-fluoroolefin copolymer, vinyl ester-fluoroolefin copolymer, sulfonic acid group
• ethylene copolymer ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer
• amorphous fluororesin such as perfluorocyclopolymer
• vinyl ether-fluoroolefin copolymer vinyl ester-fluoroolefin copolymer
• sulfonic acid group can be used, such as polytetrafluoroethylene (trade name: Nafion manufactured by DuPont).
• the concentration of the binder is such that the solid content is 0.05 to 50% by weight, preferably 0.2 to 20% by weight of the entire photocatalyst coating liquid. This is because if the concentration is less than 0.05% by weight, the adhesion to the substrate is lowered, and if it exceeds 50% by weight, the photocatalytic performance is lowered.
• the aqueous medium is water or a solvent containing water as a main component and a water-soluble organic solvent.
• water ion exchange water, RO water, distilled water, and purified water are generally used.
• water-soluble organic solvents include methyl alcohol, ethyl alcohol, isopropanol, butanol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, methyl carbitol, propylene glycol monomethyl
• the water-soluble organic solvent is preferably used in a ratio of 0 to 100 parts by weight with respect to 100 parts by weight of water.
• the proportion of the aqueous medium is 20 to 98% by weight, preferably 50 to 97% by weight, when the weight of the whole coating solution is 100% by weight.
• the proportion of the aqueous medium is less than 20% by weight, the viscosity of the coating liquid becomes high and handling becomes difficult.
• the proportion of the aqueous medium exceeds 98% by weight, the concentration of the photocatalyst particles decreases and the photocatalytic performance decreases. Because.
• the median diameter (d50% particle diameter) of the photocatalyst particles contained in the photocatalyst coating liquid of the present invention measured by the dynamic light scattering method is 5 nm to 2 ⁇ m, preferably 10 nm to 1 ⁇ m, more preferably 20 nm to 300 nm. .
• the median diameter is larger than 2 ⁇ m, the photocatalytic performance is lowered, which is not preferable.
• the pH of the photocatalyst coating solution of the present invention is 7 to 10, preferably 7 to 8. If the pH is less than 7, the above-mentioned copolymer dispersant is not dissolved and precipitates, and the dispersibility of the photocatalyst particles is lowered. If the pH is more than 10, the handling property of the coating solution such as the safety of the worker is inferior. Because.
• the photocatalyst coating liquid of the present invention may further contain other components than the above as necessary.
• the other component is, for example, one or more additives selected from a pH adjuster, antiseptic / antifungal agent, surfactant, chelating agent, leveling agent, antifoaming agent and thickener.
• the other components are added in an amount capable of imparting desired properties to the coating solution.
• the proportion of other components in the coating solution is not particularly limited and can be appropriately selected depending on the application of the coating solution.
• the photocatalyst coating liquid of the present invention is produced by adding and mixing photocatalyst particles and / or a binder to a dispersant solution obtained by dissolving a dispersant in an aqueous medium.
• a photocatalyst particle and a binder may be added to and mixed with the dispersant solution to prepare a photocatalyst dispersion
• a binder may be added to and mixed with the photocatalyst dispersion to produce a photocatalyst coating solution.
• a binder may be added to and mixed with the dispersant solution, and photocatalyst particles may be further added and mixed to produce a photocatalyst coating solution.
• a known dispersing device specifically, a device such as a medium stirring type dispersing machine, a rolling ball mill, a vibrating ball mill, or a jet mill can be used.
• a medium agitation type disperser such as a bead mill
• beads having a diameter of 2.0 mm or less are generally used as the medium (media)
• the material is zirconia, alumina, or glass.
• Mixing is carried out until the average particle diameter of the photocatalyst particles falls within the above-mentioned range.
• the photocatalyst body is formed by applying the photocatalyst coating liquid of the present invention to a surface of a substrate such as glass, plastic, metal, ceramics, and concrete, and a coating film formed on the surface of the substrate. Can be manufactured.
• the coating film can be formed by a known method such as spin coating, air knife coating, reverse roll coating, die coating, spray coating, or brush coating.
• the photocatalyst coating liquid of the present invention is applied to the surface of the paint film, in order to improve the adhesion between the photocatalyst coating liquid and the paint film, the undercoat agent is applied and then the photocatalyst coating liquid is applied. May be.
• the photocatalyst coating liquid of the present invention When the photocatalyst coating liquid of the present invention is applied to the surface of a substrate or the surface of a coating film formed on the surface of a substrate to form a coating film, the substrate surface becomes hydrophilic by light irradiation. It becomes easy to repel dirt. Therefore, the photocatalyst coating liquid of the present invention can impart good drip-proof properties, antifouling / antifogging properties, self-cleaning properties, and easy cleaning properties to the substrate surface. Moreover, the effects of deodorization, gas treatment, water treatment, antibacterial, etc. can be exhibited by the photocatalytic action.
• the photocatalyst coating solution of the present invention can be used for a dye-sensitized solar cell.
• the photocatalyst coating solution of the present invention may be used for coating on a transparent electrode (negative electrode) of a dye-sensitized solar cell.
• the photocatalyst coating liquid of the present invention is preferably used with its viscosity increased. The viscosity may be increased by adding a thickener. Moreover, you may mix a pigment
• photocatalyst The results of using an anatase-type titanium oxide photocatalyst (manufactured by Ishihara Sangyo Co., Ltd., trade name ST-21) as the photocatalyst are shown in Examples 1 to 5 and Comparative Examples 1 to 3, and a visible light responsive titanium oxide photocatalyst (manufactured by Daicel, product) Examples 6 and 7 show the results using "Name Cell Muse".
• Dispersant As the dispersant, a styrene-acrylic acid copolymer (Jonkrill 678: MW8500, acid value 215 manufactured by BASF) was used.
• styrene-acrylic acid copolymer Jonkrill 678: MW8500, acid value 215 manufactured by BASF
• lithium hydroxide, potassium hydroxide, sodium hydroxide, cesium hydroxide or 28% ammonia water all of which are Wako Pure Chemical Industries special grades
• binder As the binder, a 1% titanium peroxide solution (Tiosky Coat C manufactured by Tio-Techno Co., Ltd.) and a 20% fluorine-based resin solution (trade name Nafion, manufactured by Wako Pure Chemical Industries, Ltd.) were used.
• a dispersing agent solution was prepared by dissolving a dispersing agent in a base solution in which a predetermined amount of a basic substance was dissolved.
• Photocatalyst particles were added to the dispersant solution to prepare a photocatalyst dispersion.
• mixing was performed using a dyno mill KDL special type bead mill manufactured by Shinmaru Enterprises Co., Ltd. using beads made of zirconia having a diameter of 0.3 mm as a medium to obtain a photocatalyst coating liquid.
• Tables 1 and 2 show the compositions of the photocatalyst coating solution in each example and each comparative example.
• the pH of the obtained coating solution, the particle diameter of the photocatalyst particles in the coating solution, the stability of the coating solution over time, the coloration resistance of the coating film, the acid resistance and the photocatalytic performance were evaluated by the following methods.
• the pH of the coating solution was measured at room temperature (20 to 25 ° C.) using a pH meter manufactured by Horiba.
• the particle diameter of the photocatalyst particles in the photocatalyst coating liquid was measured by a dynamic light scattering method. For the measurement, LB550 manufactured by Horiba Ltd. was used.
• the coating solution was placed in a glass bottle and allowed to stand at room temperature for 3 months, and then the state was visually observed and evaluated based on the following criteria. ⁇ : There is no precipitation. Alternatively, the photocatalyst particles are precipitated but easily redispersed when shaken. X: The photocatalyst particle
• the coating solution was applied to a glass plate with a bar coater, dried, the coating film was heated to 200 ° C., and the colorability of the coating film was evaluated based on the following criteria. ⁇ : No color change occurs in the coating film. X: A color change arises in a coating film and coloring generate
• the coating solution was applied to a glass plate with a bar coater, and after drying, the coating film was immersed in a 10% strength aqueous hydrochloric acid solution for 24 hours and evaluated based on the following criteria. ⁇ : No peeling of the coating film is observed. X: Peeling of part or all of a coating film is seen.
• Methylene blue decomposition rate (Methylene blue concentration before light irradiation ⁇ Methylene blue concentration after light irradiation) / Methylene blue concentration before light irradiation ⁇ : Methylene blue decomposition rate 51 to 100% ⁇ : Methylene blue decomposition rate of 21-50% ⁇ : Decomposition rate of methylene blue is 0 to 20%
• Comparative Example 1 is a case where a dispersant and titanium peroxide were not added.
• Comparative Example 2 titanium peroxide was added, but no dispersant was added.
• Comparative Example 3 titanium peroxide was added, but no dispersant was added, and potassium hydroxide was added.
• the particle diameter of the photocatalyst particles became very small as compared with Comparative Examples 1 to 3 in which no dispersant was added, and both temporal stability and photocatalytic performance were improved.
• the coating film did not adhere to the substrate, and the photocatalytic performance could not be evaluated.
• Example 6 The results of Examples 6 and 7 are shown in Table 2.
• Examples 6 and 7 are the results of using a visible light responsive titanium oxide photocatalyst
• Example 6 is the result of using only titanium peroxide as a binder
• Example 7 is the result of using titanium peroxide and a fluororesin in combination as a binder. is there.
• the acid resistance of the coating film can be improved by using titanium peroxide and a fluorine-based resin in combination with the binder.
• the copolymer neutralized material used for a dispersing agent is the neutralized material of potassium salt, it is excellent in coloring resistance.

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