JP2012131650A - Method for manufacturing tungsten oxide particle dispersion liquid, method for manufacturing noble metal-carrying tungsten oxide particle dispersion liquid, and photocatalyst functional product - Google Patents

Abstract

An object of the present invention is to provide a tungsten oxide particle dispersion that has excellent dispersibility of tungsten oxide particles in a dispersion medium and does not cause solid-liquid separation even when stored.
A method for producing a tungsten oxide particle dispersion having steps (a) and (b), wherein the dispersion treatment is performed using a wet medium stirring mill while adding an alkaline compound to the mixture. A method for producing a tungsten oxide particle dispersion.
(A) A mixture is obtained by mixing tungsten oxide particles and a dispersion medium.
(B) Dispersing the mixture.
[Selection figure] None

Description

  The present invention is obtained using a method for producing a tungsten oxide particle dispersion, a method for producing a noble metal-supported tungsten oxide particle dispersion, and a tungsten oxide particle dispersion or a noble metal-supported tungsten oxide particle dispersion obtained by these production methods. The present invention relates to a photocatalyst functional product.

  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 that can exhibit such a photocatalytic action is called a photocatalyst. Tungsten oxide is known as such a photocatalyst. Tungsten oxide is a photocatalyst that exhibits high photocatalysis under the illumination of a fluorescent lamp.

In order to use the photocatalyst for various members, it is convenient to apply a photocatalyst dispersion liquid in which the photocatalyst is dispersed in a dispersion medium to various members. The tungsten particle dispersion has low dispersibility of the tungsten oxide particles in the dispersion medium, and aggregation of the tungsten oxide particles may occur.

Patent Document 1 discloses a photocatalyst dispersion (tungsten oxide particle dispersion) containing tungsten oxide particles and a dispersion medium, in which the surface of the tungsten oxide particles is replaced with a hydroxyl group to increase the absolute value of the zeta potential. In order to improve the above, a photocatalyst dispersion in which the pH of the dispersion medium is in the range of 2.1 to 5.7 is disclosed.

JP 2009-240979 A

  However, the photocatalyst dispersion described in Patent Document 1 does not have sufficient dispersibility of tungsten oxide particles, and it is found that solid-liquid separation accompanying aggregation of tungsten oxide particles occurs when the photocatalyst dispersion is stored. It was.

Therefore, as a result of intensive studies to solve the above problems, the present inventor has excellent dispersibility of tungsten oxide particles in a dispersion medium in which the tungsten oxide particle dispersion produced by the production method having the following configuration is excellent. The inventors have found that solid-liquid separation does not occur even when stored, and have completed the present invention.
(1) A method for producing a tungsten oxide particle dispersion having steps (a) and (b), wherein the dispersion treatment is performed using a wet medium stirring mill while adding an alkaline compound to the mixture. A method for producing a tungsten oxide particle dispersion.
(A) A mixture is obtained by mixing tungsten oxide particles and a dispersion medium.
(B) Dispersing the mixture.
(2) The manufacturing method as described in said (1) whose content of a tungsten oxide particle is 15-50 weight part with respect to 100 weight part of tungsten oxide particle dispersion liquid.
(3) A light having a precious metal precursor added to the tungsten oxide particle dispersion obtained by the production method according to any one of (1) and (2), and then having energy equal to or higher than the band gap of the tungsten oxide particles. For producing a noble metal-supported tungsten oxide particle dispersion.
(4) The production method according to (3), wherein the noble metal is at least one selected from the group consisting of Cu, Pt, Au, Pd, Ag, Ru, Ir, and Rh.
(5) A photocatalytic functional product having a photocatalyst layer on the surface of the substrate, wherein the photocatalyst layer is formed using a dispersion obtained by the production method according to any one of (1) to (4). Photocatalytic functional products.

  ADVANTAGE OF THE INVENTION According to this invention, the dispersibility of the tungsten oxide particle in a dispersion medium is excellent, and the tungsten oxide particle dispersion liquid which does not produce solid-liquid separation even if it can store can be provided. Further, according to the present invention, there is provided a noble metal-supported tungsten oxide particle dispersion in which noble metal is supported on tungsten oxide particles, the particles are excellent in dispersibility in a dispersion medium, and solid-liquid separation does not occur even when stored. can do.

X-ray diffraction spectrum of solid content obtained by vacuum drying the tungsten oxide particle dispersion obtained in Example 1, and solid content obtained by vacuum drying the tungsten oxide particle dispersion obtained in Comparative Example 1. It is a figure which shows an X-ray diffraction spectrum.

  In the method for producing tungsten oxide particles of the present invention, tungsten oxide particles and a dispersion medium are mixed to obtain a mixture, and the mixture is dispersed using a wet medium stirring mill while adding an alkaline compound to the mixture. A tungsten oxide particle dispersion is produced.

(Tungsten oxide particles)
The tungsten oxide particles are not particularly limited as long as they are particulate tungsten oxide exhibiting a photocatalytic action, and examples thereof include tungsten trioxide (WO ₃ ) particles. The tungsten oxide particles may be used alone or in combination of two or more.

  The tungsten oxide particles can be obtained, for example, by adding an acid to an aqueous solution of tungstate to obtain tungstic acid as a precipitate and baking the obtained tungstic acid. Moreover, it can also obtain by the method of heating and thermally decomposing ammonium metatungstate and ammonium paratungstate. Further, it can be obtained by a method of burning metallic tungsten particles.

  The particle diameter of the tungsten oxide particles is not particularly limited, but in terms of photocatalysis, the average dispersed particle diameter is usually 50 to 200 nm, preferably 80 to 130 nm.

(Dispersion medium)
As the dispersion medium, an aqueous medium mainly containing water, specifically, a water content of 50% by mass or more is used, and water alone or water and a water-soluble organic solvent may be used. It may be a mixed medium.
Examples of the water-soluble organic solvent include water-soluble alcohols such as methanol, ethanol, propanol, and butanol, acetone, methyl ethyl ketone, ethyl cellosolve, butyl cellosolve, ethyl acetate, and diethyl ether. In addition, a water-soluble organic solvent may be used independently and may use 2 or more types together.
The usage-amount of a dispersion medium is 3 mass times-200 mass times normally with respect to a tungsten oxide particle. If the amount of the dispersion medium used is less than 3 times by mass, the tungsten oxide particles are likely to settle, and if it exceeds 200 times by mass, it is disadvantageous in terms of volume efficiency.

(Distributed processing)
The dispersion treatment is performed using a wet medium stirring mill while mixing the tungsten oxide particles and the dispersion medium to obtain a mixture and adding an alkaline compound to the mixture. By performing such a dispersion treatment, it is possible to improve the dispersibility of the tungsten oxide particles in the dispersion medium, and to obtain a tungsten oxide particle dispersion in which solid-liquid separation does not occur even when stored. The reason for this is that when a dispersion treatment of tungsten oxide particles and a dispersion medium is performed using a wet medium agitation mill, the tungsten oxide particles are subjected to a mechanochemical action due to collision with beads serving as a grinding medium, thereby producing crystals. Tungstic acid particles (H ₂ WO ₄ ) are generated, and the tungstic acid particles function as an aggregating agent for the tungsten oxide particles, so that the tungsten oxide particles are easily aggregated and the dispersibility is lowered. By adding an alkaline compound, it is guessed that the production | generation of a tungstic acid particle is suppressed and the fall of the dispersibility of the tungsten oxide particle in a dispersion medium is suppressed.
The formation of crystalline tungstic acid particles can be confirmed, for example, by measuring an X-ray diffraction spectrum of a powder obtained by drying a tungsten oxide particle dispersion.

  The amount of tungsten oxide particles mixed in the dispersion medium is preferably 15 to 50 parts by weight with respect to 100 parts by weight of the dispersion. When the mixing amount of the tungsten oxide particles is less than 15 parts by mass, the concentration of the obtained tungsten oxide particle dispersion becomes thin, and there is a possibility that an operation such as concentration may be required depending on the application when using this. On the other hand, if the mixing amount exceeds 50 parts by weight, the efficiency of the dispersion treatment may be significantly reduced.

Examples of the alkaline compound added to the mixture include aqueous ammonia, lithium hydroxide aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, potassium carbonate aqueous solution, ammonium carbonate aqueous solution, sodium bicarbonate aqueous solution, carbonic acid carbonate, and the like. Examples thereof include an aqueous potassium hydrogen solution and an aqueous ammonium hydrogen carbonate solution.
The addition amount of the alkaline compound is preferably such that the pH of the tungsten oxide particle dispersion is maintained within the range of 2.2 to 4.0, preferably within the range of 2.4 to 3.0. When the addition amount of the alkaline compound is small and the pH of the tungsten oxide particle dispersion is less than 2.2, the formation of tungstic acid particles is not sufficiently suppressed, and the decrease in the dispersibility of the tungsten oxide particles in the dispersion medium is suppressed. May become insufficient. Further, when the amount of the alkaline compound added is large and the pH of the tungsten oxide particle dispersion exceeds 4.0, the tungsten oxide particles dissolve in the dispersion medium, and the photocatalytic action of the tungsten oxide particles obtained from the tungsten oxide particle dispersion May decrease.

As a method for adding the alkali compound, a method using a pH controller having a control mechanism for adjusting the pH to be constant is preferable because the pH value can be arbitrarily controlled.
The addition of the alkaline compound may be performed continuously while using the wet medium stirring mill, may be performed intermittently, or may be performed at intervals of a certain period.

(Tungsten oxide particle dispersion)
Thus, a tungsten oxide particle dispersion is obtained by dispersing the mixture using a wet medium stirring mill while adding an alkaline compound to the mixture. The tungsten oxide particles are dispersed in the dispersion medium without settling. The dispersion in which the tungsten oxide particles are dispersed is excellent in dispersibility of the tungsten oxide particles, and is easy to handle because solid-liquid separation associated with aggregation of the tungsten oxide particles does not occur even when stored.

(Precious metal precursor)
In the present invention, it is preferable that a noble metal or a precursor thereof is added to the tungsten oxide particle dispersion and supported on the tungsten oxide particles. A noble metal is a compound that can be supported on tungsten oxide particles and can exhibit electron withdrawing properties, and a noble metal precursor is a compound that can transition to a noble metal on the surface of tungsten oxide particles (for example, reduced to a noble metal by light irradiation). Compound). When the noble metal is supported on the tungsten oxide particles, recombination between electrons excited in the conduction band by irradiation of light and holes generated in the valence band is suppressed, and the photocatalytic action can be further enhanced.

  As the noble metal precursor used in the present invention, those which can be dissolved in a dispersion medium are used. When such a precursor is dissolved, the noble metal element constituting the precursor usually becomes a noble metal ion having a positive charge and exists in the dispersion medium. The noble metal ions are reduced to zero-valent noble metal by light irradiation and are supported on the surface of the tungsten oxide particles. Examples of the noble metal include Cu, Pt, Au, Pd, Ag, Ru, Ir, and Rh. Examples of the precursor include hydroxides, nitrates, sulfates, halides, organic acid salts, carbonates, and phosphates of these noble metals. Among these, from the viewpoint of obtaining high photocatalytic activity, the noble metal is preferably Cu, Pt, Au, or Pd.

Examples of the Cu precursor include 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 copper 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 ) and the like.

Examples of the precursor of Pt include platinum chloride (PtCl ₂ , PtCl ₄ ), platinum bromide (PtBr ₂ , PtBr ₄ ), platinum iodide (PtI ₂ , PtI ₄ ), potassium tetrachloroplatinate (K ₂ PtCl ₄ ). ₄ ), hexachloroplatinic acid (H ₂ PtCl ₆ ), potassium hexachloroplatinate (K ₂ PtCl ₆ ), platinum sulfite (H ₃ Pt (SO ₃ ) ₂ OH), tetraammineplatinum chloride (Pt (NH ₃ ) ₄ Cl ₂ ), Tetraammineplatinum hydrogen carbonate (C ₂ H ₁₄ N ₄ O ₆ Pt), tetraammineplatinum hydrogen phosphate (Pt (NH ₃ ) ₄ HPO ₄ ), tetraammineplatinum hydroxide (Pt (NH ₃ ) ₄ (OH) ₂ ) , Tetraammineplatinum nitrate (Pt (NO ₃ ) ₂ (NH ₃ ) ₄ ), tetraammineplatinum tetrachloroplatinum ((Pt (NH ₃ ) ₄ ) (PtCl ₄ )), Dinitrodiamine platinum (Pt (NO ₂ ) ₂ (NH ₃ ) ₂ ) and the like.

Examples of the Au precursor include gold chloride (AuCl), gold bromide (AuBr), gold iodide (AuI), gold hydroxide (Au (OH) ₂ ), tetrachloroauric acid (HAuCl ₄ ), tetra Examples include potassium chloroaurate (KAuCl ₄ ) and potassium tetrabromoaurate (KAuBr ₄ ).

Examples of the precursor of Pd include 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 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 ), tetraammine palladium nitrate (Pd (NH ₃ ) ₄ (NO ₃ ) ₂ ), tetraammine palladium tetra chloropalladate acid _{((Pd (NH 3) 4} ) (PdCl 4)), Te Etc. La chloro palladium ammonium _{((NH 4) 2 PdCl 4} ) and the like.

  The noble metal precursors may be used alone or in combination of two or more. The amount used is usually 0.005 parts by mass or more in terms of cost, in terms of obtaining a sufficient effect of improving the photocatalytic action with respect to 100 parts by mass of the photocatalyst particles in terms of noble metal atoms. Is usually 1 part by mass or less, preferably 0.01 part by mass to 0.6 part by mass, and more preferably 0.05 to 0.2 part by mass.

(Light irradiation)
In the present invention, it is preferable to add a precursor of a noble metal to the tungsten oxide particle dispersion and then irradiate with light. You may perform irradiation of the light to a tungsten oxide particle dispersion liquid, stirring. Irradiation may be performed from inside or outside the tube while passing through a transparent glass or plastic tube, or this may be repeated. The light source is not particularly limited as long as it can irradiate light having energy higher than the band gap of tungsten oxide particles. Specific examples include germicidal lamps, mercury lamps, light emitting diodes, fluorescent lamps, halogen lamps, xenon lamps, solar Light can be used. The wavelength of the irradiated light is usually 180 nm to 500 nm. The time for the light irradiation is usually 20 minutes or longer, preferably 1 hour or longer, usually 24 hours or shorter, preferably 6 hours or shorter because a sufficient amount of noble metal can be supported. When the time exceeds 24 hours, most of the precursors of the noble metal have been supported as noble metals by that time, and an effect commensurate with the cost of light irradiation cannot be obtained.

(Sacrificial agent)
In the present invention, it is preferable to add the sacrificial agent to the tungsten oxide particle dispersion added with the noble metal precursor. Examples of the sacrificial agent include alcohols such as ethanol, methanol, and propanol, ketones such as acetone, and carboxylic acids such as oxalic acid. When the sacrificial agent is a solid, the sacrificial agent may be used by dissolving in a suitable solvent, or may be used as a solid. The sacrificial agent may be added to the raw material dispersion before performing light irradiation, or the raw material liquid may be irradiated with light for a certain period of time, and then the sacrificial agent may be added and further irradiated with light. . The amount of the sacrificial agent is usually 0.001 to 0.3 times by mass, preferably 0.005 to 0.1 times by mass with respect to the dispersion medium. If the amount of the sacrificial agent used is less than 0.001 mass times, the noble metal is insufficiently supported on the tungsten oxide particles. If the amount of the sacrificial agent exceeds 0.3 mass times, the amount of the sacrificial agent is excessive and an effect corresponding to the cost cannot be obtained. .

(PH adjustment)
In the present invention, light irradiation is carried out while maintaining the pH of the tungsten oxide particle dispersion added with the noble metal precursor within a range of 2.5 to 4.5, preferably 2.7 to 3.5. Do. Usually, when the noble metal is supported on the surface of the tungsten oxide particles by light irradiation, the pH of the dispersion gradually changes to acidic. Therefore, in order to maintain the pH within the above range, a base is usually added. Examples of the base include aqueous solutions of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, etc. Among them, aqueous ammonia and hydroxide It is preferable to use a sodium aqueous solution or a potassium hydroxide aqueous solution.

(Precious metal-supported tungsten oxide particle dispersion)
Thus, by irradiating with light, the noble metal precursor becomes a noble metal and is supported on the tungsten oxide particles to obtain noble metal-supported tungsten oxide particles. The noble metal-supported tungsten oxide particles are dispersed in the used dispersion medium without settling. The dispersion in which the noble metal-supported tungsten oxide particles are dispersed is excellent in dispersibility of the noble metal-supported tungsten oxide particles, and even when stored, solid-liquid separation associated with aggregation of the noble metal-supported tungsten oxide particles does not occur and is easy to handle.

  The tungsten oxide particle dispersion and the noble metal-supported tungsten oxide particle dispersion may contain various known additives as long as the effects of the present invention are not impaired. Examples of additives include amorphous silica, silica sol, water glass, silicon compounds such as organopolysiloxane, amorphous alumina, alumina sol, aluminum compounds such as aluminum hydroxide, aluminosilicates such as zeolite and kaolinite, oxidation Alkaline earth metal oxides such as magnesium, calcium oxide, strontium oxide, barium oxide, alkaline earth metal hydroxides such as magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Co, Ni, Ru, Rh, Os, Ir, Ag, Zn, Cd, Ga, In, Tl, Ge, Sn, Pb, Hydroxides and oxides of metal elements such as Bi, La and Ce, calcium phosphate, molecular Sieve, active carbon, a polycondensation product of an organopolysiloxane compound, phosphate, a fluorine-based polymer, silicone-based polymers, acrylic resins, polyester resins, melamine resins, urethane resins, alkyd resins. When these additives are added and used, they can be used alone or in combination of two or more.

  The additive can also be used as a binder for holding the photocatalyst particles more firmly on the surface of the substrate when the photocatalyst layer is formed on the surface of the substrate using the dispersion of the present invention. (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 JP-A-11-1620, JP-A-11-1661, JP-A-2004-059686, JP-A-2004-107381, JP-A-2004-256590, JP-A-2004-359902, (See JP 2005-113028, JP 2005-230661, JP 2007-161824, etc.).

(Photocatalytic product)
The photocatalytic functional product of the present invention has a photocatalyst layer formed on the surface using the tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion. Here, the photocatalyst layer is formed by a conventionally known composition such as, for example, volatilizing the dispersion medium after applying the tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion of the present invention to the surface of the substrate (product). It can be formed by a film method. The film thickness of the photocatalyst body layer is not particularly limited, and usually may be appropriately set from several hundred nm to several mm according to the application. The photocatalyst layer may be formed on any part as long as it is an inner surface or an outer surface of the base material (product). For example, the photocatalyst layer is a surface irradiated with light (visible light), and a malodorous substance. It is preferably formed on a surface that is continuously or intermittently connected to a place where the occurrence of a pathogen or a pathogen or virus is present. The material of the base material (product) is not particularly limited as long as the formed photocatalyst layer can be held at a strength that can be practically used. For example, plastic, metal, ceramics, wood, concrete, paper, etc. , Products made of any material can be targeted. In addition, in order to suppress the deterioration of the adhesion between the photocatalyst layer and the substrate due to the photocatalytic action, a known barrier layer made of, for example, a silica component can be formed between the photocatalyst layer and the substrate.

As the plastic, in the case of a thermosetting resin, for example, aramid resin, polyimide resin, epoxy resin, unsaturated polyester resin, phenol resin, urea resin, polyurethane resin, melamine resin, benzoguanamine resin, silicone resin, melamine urea Examples thereof include resins.
Examples of the plastic include, in the case of a thermoplastic resin, a resin obtained by polymerizing a condensation polymerization resin or a vinyl monomer.

  Examples of the condensation polymerization resin include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polylactic acid, biodegradable polyester, and polyester liquid crystal polymer; ethylenediamine-adipic acid polycondensate (nylon-66), nylon-6 And polyamide resins such as nylon-12 and polyamide liquid crystal polymers; polyether resins such as polycarbonate resins, polyphenylene oxide, polymethylene oxide, and acetal resins; polysaccharide resins such as cellulose and derivatives thereof; and the like.

  Examples of resins obtained by polymerizing vinyl monomers include polyolefin resins; polystyrene, poly-α-methylstyrene, styrene-ethylene-propylene copolymers (polystyrene-poly (ethylene / propylene) block copolymers), Styrene-ethylene-butene copolymer (polystyrene-poly (ethylene / butene) block copolymer), styrene-ethylene-propylene-styrene copolymer (polystyrene-poly (ethylene / propylene) -polystyrene block copolymer), Unsaturated aromatic-containing resins such as ethylene-styrene copolymers; polyvinyl alcohol resins such as polyvinyl alcohol and polyvinyl butyral; polymethyl methacrylate, methacrylic acid ester, acrylic acid ester, methacrylic acid amide as monomers Acrylic resins containing chloric acid amides; chlorinated resins such as polyvinyl chloride and polyvinylidene chloride, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetra And fluororesin such as fluoroethylene-hexafluoropropylene copolymer and polyvinylidene fluoride;

The photocatalytic functional product of the present invention can be used not only outdoors but also fluorescent lamps, sodium lamps,
And indoor environments that only receive light from visible light sources such as white light emitting diodes,
High photocatalytic action is exhibited by light irradiation. Therefore, the tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained by the production method of the present invention can be used, for example, for building materials such as ceiling materials, tiles, glass, wallpaper, wall materials, floors, automobile interior materials ( Automotive instrument panels, automotive seats, automotive ceilings), home appliances such as refrigerators and air conditioners, textile products such as clothing and curtains, etc. When dried and exposed to light from indoor lighting, formaldehyde, acetaldehyde, etc. Volatile organic substances, aldehydes, mercaptans, ammonia and other malodorous substances, reduce the concentration of nitrogen oxides, Staphylococcus aureus, Escherichia coli, anthrax, tuberculosis, cholera, diphtheria, tetanus, plague, Kill, decompose, and remove pathogenic bacteria such as Shigella, Clostridium 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 virus, cowpox virus, varicella virus, measles virus, adenovirus, coxsackie virus, calicivirus, It can detoxify retrovirus, coronavirus, avian influenza virus, human influenza virus, swine influenza virus, norovirus and its recombinants, and further allergens such as mite allergen and cedar pollen allergen It is possible to Gaika. In addition, the photocatalytic functional product of the present invention is not only capable of exhibiting sufficient hydrophilicity and exhibiting antifogging properties when irradiated with visible light, but also can be easily wiped off by simply applying water to the dirt. In addition, charging can be prevented.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.
In addition, the measuring method in each Example is as follows.

1. Average dispersed particle size (nm)
Using a Microtrac UPA particle size analyzer (manufactured by Nikkiso Co., Ltd.), the cumulative 50% diameter and 90% diameter were measured by the dynamic scattering method to obtain dispersed particle diameters d50 (nm) and d90 (nm), respectively. .

2. X-ray diffraction spectrum The X-ray diffraction spectrum was measured using an X-ray diffractometer ("RINT2000 / PC" manufactured by Rigaku Corporation), and the presence or absence of crystalline tungstic acid particles was confirmed from the X-ray diffraction spectrum.

3. Measurement of acetaldehyde resolution The photocatalytic activity was evaluated by measuring the first-order rate constant in the decomposition reaction of acetaldehyde under irradiation of light from a fluorescent lamp. That is, in a glass petri dish (outer diameter: 70 mm, inner diameter: 66 mm, height: 14 mm, capacity: about 48 mL), the obtained noble metal-supported tungsten oxide particle dispersion liquid has a drop amount in terms of solid content per unit area of the bottom surface of 1 g / m. ^It was dripped so that it might become ^2, and it formed uniformly in the whole bottom face of a petri dish. Next, the petri dish was dried by holding it in the air at 110 ° C. for 1 hour in the air to form a photocatalyst layer on the bottom of the glass petri dish. The photocatalyst layer has an ultraviolet intensity of ² mW / cm ² (measured by attaching a UV receiver “UD-36” to Topcon's UV intensity meter “UVR-2”) and receiving 16 UV rays from the black light. This was used as a sample for photocatalytic activity measurement after time irradiation.

Next, the sample for photocatalytic activity measurement is put together with the petri dish in a gas bag (internal volume 1 L) and sealed, and then the inside of the gas bag is evacuated, and then the volume ratio of oxygen to nitrogen is 1: 4. Was mixed with 0.6 L of a mixed gas, and 3 mL of nitrogen gas containing 1% acetaldehyde was sealed therein, and the mixture was kept in the dark at room temperature for 1 hour. Then, using a commercially available white fluorescent lamp as the light source, irradiate the fluorescent lamp light from the outside of the gas bag so that the illuminance in the vicinity of the measurement sample is 1000 lx (measured with the illuminometer “T-10” manufactured by Minolta). Then, acetaldehyde was decomposed. At this time, the intensity of the ultraviolet rays in the vicinity of the measurement sample was 6.5 μW / cm ² (measured by attaching a UV receiver “UD-36” manufactured by Topcon to an ultraviolet intensity meter “UVR-2” manufactured by Topcon). The gas in the gas bag was sampled every 1.5 hours after the light irradiation of the fluorescent lamp was started, and the concentration of acetaldehyde was measured with a gas chromatograph (“GC-14A” manufactured by Shimadzu Corporation). Then, a first-order rate constant was calculated from the concentration of acetaldehyde with respect to the irradiation time, and this was evaluated as acetaldehyde resolution. It can be said that the higher the first-order rate constant, the higher the resolution of acetaldehyde, that is, the photocatalytic activity.

Example 1
As a dispersion medium, 1 kg of tungsten oxide particles (manufactured by Nippon Shin Metal Co., Ltd.) was added to 4 kg of ion-exchanged water and mixed to obtain a mixture. This mixture was subjected to a dispersion treatment using a wet medium stirring mill (manufactured by Kotobuki Giken Co., Ltd., “Ultra Apex Mill UAM-1”) to obtain a tungsten oxide particle dispersion. During the dispersion treatment, a pH controller (set to pH = 2.5) connected to the pH electrode and connected to the pH electrode, and having a control mechanism for adjusting the pH to a constant level by supplying ammonia water, NH ₃ was added to keep the pH of the tungsten oxide particle dispersion at a constant 2.5. The amount of NH ₃ added was 2.2 g.

Of the dispersed particle diameter of the tungsten oxide particles in the obtained tungsten oxide particle dispersion, d50 was 67 nm and d90 was 116 nm. Further, when this tungsten oxide particle dispersion was stored at room temperature for 7 days, d50 was 65 nm and d90 was 123 nm out of the dispersion particle diameter of tungsten oxide particles, and solid-liquid separation was not observed during storage. The tungsten oxide particle dispersion after storage had a pH of 3.4.
Moreover, when the obtained tungsten oxide particle dispersion liquid is vacuum-dried to obtain a solid content, and the X-ray diffraction spectrum of the obtained solid content is measured, a peak of tungsten oxide (WO ₃ ) is observed as shown in FIG. It was done. On the other hand, no peak of tungstic acid (H ₂ WO ₄ ) was observed, and generation of crystalline tungstic acid particles was not confirmed.

To this tungsten oxide particle dispersion, an aqueous solution of hexachloroplatinic acid (H ₂ PtCl ₆ ) is added so that hexachloroplatinic acid is 0.12 parts by mass with respect to 100 parts by mass of tungsten oxide particles in terms of platinum atoms, A hexachloroplatinic acid-containing tungsten oxide particle dispersion was obtained. The solid content (amount of tungsten oxide particles) contained in 100 parts by mass of this dispersion was 17 parts by mass (solid content concentration 17% by mass).

  Next, a pH controller (set to pH = 3.5) connected to the pH electrode and connected to the pH electrode and having a control mechanism for adjusting the pH to a constant level by supplying ammonia water is provided. 1200 g of the hexachloroplatinic acid-containing tungsten oxide particle dispersion is circulated at a rate of 1 L / min with a light irradiation device comprising a glass tube (inner diameter 37 mm, height 360 mm) provided with “GLD15MQ”), and light irradiation (ultraviolet rays) is performed. While performing, aqueous ammonia was added with a pH controller to adjust the pH of the hexachloroplatinic acid-containing tungsten oxide particle dispersion to 3.5. The time of light irradiation was 2 hours. Thereafter, while continuing to circulate, methanol was further added so that its concentration was 1% by mass of the total solvent, and irradiation with light (ultraviolet rays) was performed for 3 hours to obtain a platinum-supported tungsten oxide particle dispersion. During the light irradiation, aqueous ammonia was added by a pH controller, and the pH of the dispersion was maintained at 3.5.

When the obtained platinum-supported tungsten oxide particle dispersion was stored at 20 ° C. for 8 days, no solid-liquid separation was observed.
Moreover, when the photocatalytic activity of the photocatalyst body layer formed using the obtained platinum carrying | support tungsten oxide particle dispersion liquid was evaluated, the first-order rate constant was 0.12h- ¹ .

(Comparative Example 1)
A tungsten oxide particle dispersion was prepared in the same manner as in Example 1 except that ammonia water was not added with a pH controller. The pH of the tungsten oxide particle dispersion was 2.1.

Of the dispersed particle diameter of the tungsten oxide particles in the obtained tungsten oxide particle dispersion, d50 was 97 nm and d90 was 123 nm. Furthermore, when this tungsten oxide particle dispersion was stored at 20 ° C. for 7 days, d50 was 110 nm and d90 was 244 nm out of the dispersion particle diameter of the tungsten oxide particles, and solid-liquid separation was observed during storage. The pH was 2.5.
Further, the obtained tungsten oxide particle dispersion is vacuum-dried to obtain a solid content. When the X-ray diffraction spectrum of the solid content after the dispersion treatment is measured, the peak of tungsten oxide (WO ₃ ) is obtained as shown in FIG. In addition, the peak of tungstic acid (H ₂ WO ₄ ) was observed around 2θ = 16.5 ° and 25.5 ° (near the arrow), confirming the formation of crystalline tungstic acid particles.

The tungsten oxide particle dispersion of Example 1 was excellent in dispersion stability and solid-liquid separation was not observed. Further, the platinum-supported tungsten oxide particle dispersion of Example 1 was excellent in dispersion stability, showed no solid-liquid separation, and exhibited higher photocatalytic activity. In contrast, the tungsten oxide particle dispersion of Comparative Example 1 had low dispersion stability and solid-liquid separation was observed.

(Reference Example 1)
The photocatalyst layer can be formed on the surface of the ceiling material by applying the tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 to the surface of the ceiling material constituting the ceiling and drying. 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, and pathogens such as Staphylococcus aureus and Escherichia coli. Viruses such as avian influenza virus, human influenza virus, and swine influenza virus can be killed, and allergens such as mite allergens and cedar pollen allergens 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)
By applying and drying the tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 on a tile constructed on an indoor wall surface, a photocatalyst layer can be formed on the tile surface. As a result, the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor spaces can be reduced by light irradiation by indoor lighting, and pathogens such as Staphylococcus aureus and Escherichia coli, and birds Viruses such as influenza virus, human influenza virus, and swine influenza virus can be killed, and allergens such as mite allergens and cedar pollen allergens 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)
By applying the tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 to the indoor side surface of the window glass and drying, a photocatalyst layer can be formed on the glass surface. By irradiating light with indoor lighting, the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor space can be reduced, pathogenic bacteria such as Staphylococcus aureus and Escherichia coli, and avian influenza virus In addition, viruses such as human influenza virus and swine influenza virus can be killed, and allergens such as mite allergens and cedar pollen allergens 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)
The tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 can be applied to the wallpaper and dried to form a photocatalyst layer on the surface of the wallpaper. By constructing on the wall surface, it is possible to 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, such as Staphylococcus aureus and Escherichia coli. It can also kill pathogenic bacteria, viruses such as avian influenza virus, human influenza virus, and swine influenza virus, and can also detoxify allergens such as mite allergens and cedar pollen allergens. Furthermore, the surface of the wallpaper becomes hydrophilic, so that dirt can be easily wiped off, and charging can be prevented.

(Reference Example 5)
The tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 can be applied to the indoor floor surface and dried to form a photocatalyst layer on the floor surface. Light irradiation can reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor spaces, causing pathogens such as Staphylococcus aureus and Escherichia coli, avian influenza viruses and humans Viruses such as influenza virus and swine influenza virus can be killed, 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)
The tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 is applied to the surface of an automobile interior material such as an instrument panel for automobiles, an automobile seat, an automobile ceiling material, and an automobile glass interior. By applying and drying, a photocatalyst layer can be formed on the surface of these automobile interior materials, and as a result, volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene etc.) ) And malodorous substances, and pathogens such as Staphylococcus aureus and Escherichia coli, and viruses such as avian influenza virus, human influenza virus and swine influenza virus can be killed. No allergens such as pollen allergens It can also be of. 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)
The noble metal-supported photocatalyst particle dispersion obtained in Example 1 is applied to the surface of the air conditioner and dried, whereby a photocatalyst layer can be formed on the surface of the air conditioner. It can reduce the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in the space, pathogenic bacteria such as Staphylococcus aureus and Escherichia coli, avian influenza virus, human influenza virus and swine influenza virus Viruses can be killed, and allergens such as mite allergens and cedar pollen allergens 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)
The tungsten oxide particle dispersion or the noble metal-supported tungsten oxide particle dispersion obtained in Example 1 can be applied to the refrigerator and dried to form a photocatalyst layer in the refrigerator. The concentration of volatile organic substances (such as ethylene) and malodorous substances in the refrigerator can be reduced by illumination or light irradiation from the light source in the refrigerator, and pathogens such as Staphylococcus aureus and Escherichia coli, avian influenza virus and human influenza Viruses such as viruses and swine influenza viruses can be killed, and allergens such as mite allergens and cedar pollen allergens 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)
By applying the tungsten oxide particle dispersion liquid or the noble metal-supported tungsten oxide particle dispersion liquid obtained in Example 1 to the surface of a base material that is contacted by an unspecified number of people, such as train straps and elevator buttons, A photocatalyst layer can be formed on the surface of these substrates, thereby reducing the concentration of volatile organic substances (for example, formaldehyde, acetaldehyde, acetone, toluene, etc.) and malodorous substances in indoor spaces by light irradiation by indoor lighting. It can also kill pathogenic bacteria such as Staphylococcus aureus and Escherichia coli, viruses such as avian influenza virus, human influenza virus and swine influenza virus, and also render allergens such as mite allergen and cedar pollen allergen 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 (5)

A method for producing a tungsten oxide particle dispersion having steps (a) and (b), wherein the dispersion treatment is performed using a wet medium stirring mill while adding an alkaline compound to the mixture. A method for producing a tungsten oxide particle dispersion.
(A) A mixture is obtained by mixing tungsten oxide particles and a dispersion medium.
(B) Dispersing the mixture.   The production method according to claim 1, wherein the content of the tungsten oxide particles is 15 to 50 parts by weight with respect to 100 parts by weight of the tungsten oxide particle dispersion.   A noble metal-supported oxidation in which a precursor of a noble metal is added to the tungsten oxide particle dispersion obtained by the production method according to claim 1 and then irradiated with light having energy higher than the band gap of the tungsten oxide particles. A method for producing a tungsten particle dispersion.   The production method according to claim 3, wherein the noble metal is at least one selected from the group consisting of Cu, Pt, Au, Pd, Ag, Ru, Ir, and Rh.   It is a photocatalyst functional product provided with a photocatalyst layer on the substrate surface, and the photocatalyst layer is formed using the dispersion obtained by the production method according to any one of claims 1 to 4.

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