WO2020050147A1 - Photocatalyst supporting structure and production method - Google Patents

Photocatalyst supporting structure and production method Download PDF

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Publication number
WO2020050147A1
WO2020050147A1 PCT/JP2019/034037 JP2019034037W WO2020050147A1 WO 2020050147 A1 WO2020050147 A1 WO 2020050147A1 JP 2019034037 W JP2019034037 W JP 2019034037W WO 2020050147 A1 WO2020050147 A1 WO 2020050147A1
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WIPO (PCT)
Prior art keywords
photocatalyst
forming
component
coating solution
photocatalyst layer
Prior art date
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PCT/JP2019/034037
Other languages
French (fr)
Japanese (ja)
Inventor
優樹 塩澤
大哉 小林
光広 柳田
Original Assignee
太陽工業株式会社
日本曹達株式会社
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Application filed by 太陽工業株式会社, 日本曹達株式会社 filed Critical 太陽工業株式会社
Priority to CN201980064457.XA priority Critical patent/CN112789109A/en
Priority to JP2020541172A priority patent/JP7220224B2/en
Publication of WO2020050147A1 publication Critical patent/WO2020050147A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L9/00—Disinfection, sterilisation or deodorisation of air
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L9/00—Disinfection, sterilisation or deodorisation of air
    • A61L9/01—Deodorant compositions
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of zinc, cadmium or mercury
    • 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
    • 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
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • 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
    • C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
    • 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
    • C09D201/00—Coating compositions based on unspecified macromolecular compounds
    • 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
    • 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

Definitions

  • the present invention relates to a photocatalyst-supporting structure, a coating solution for forming the same, and a method for producing the structure, and a method for suppressing the growth or propagation of algae by the structure, and decomposing and removing nitrogen oxides. About the method.
  • This application claims priority to Japanese Patent Application No. 2018-164788 filed on September 3, 2018, the content of which is incorporated herein by reference.
  • Photocatalytic materials are used for facilitating the removal of dirt or supporting the growth and propagation of microorganisms such as bacteria, molds and algae by supporting them on the surface of materials such as exterior materials of buildings. . It is also known that such materials are effective in purifying the atmosphere by removing air pollutants such as nitrogen oxides (NOx) by decomposition. In order to obtain the effect of suppressing the growth and propagation of microorganisms such as algae, it may not be sufficient to use a photocatalytic material as a sole active ingredient. This may be because the photocatalytic material is super-hydrophilic and the surface is easily moisturized.
  • NOx nitrogen oxides
  • Patent Document 1 a metal such as silver or copper or a compound thereof having a microbial control activity by itself
  • Patent Document 2 a composition containing a zinc compound such as zinc oxide is known as a composition for obtaining an anti-algal effect in water
  • Zinc oxide has been widely used as a filler for pigments and paints, pharmaceuticals, cosmetic ingredients, ultraviolet shielding agents, antistatic agents, semiconductor materials, and the like, in addition to the purpose of controlling microorganisms and deodorizing.
  • Patent Document 3 zinc oxide doped with other elements such as aluminum and gallium has excellent conductivity and also has a heat ray shielding effect, and is often used for these effects.
  • Patent Literature 4 describes a photocatalyst formulation that exhibits an excellent NOx decomposition effect when used in combination with a photocatalyst material and an amphoteric metal oxide. As a specific example of use, the composition is applied to the tile surface and fixed by heat treatment. Although an embodiment having antibacterial properties is also described, it can exert its effect by containing the same metal or a compound thereof as in Patent Document 1 or the like as an additional component, and can avoid the above-mentioned disadvantages. is not.
  • Patent Literature 5 describes that a photocatalytic material containing two types of photocatalysts, porous titanium oxide and noble metal-supported zinc oxide particles, decomposes NOx by light irradiation. Tent grounds are also used for structures that are provided outdoors for a long period of time, and depending on the environment, the growth and propagation of algae may become a problem, as in the case of exterior materials. On the other hand, since tents of type B or C contain a synthetic resin such as vinyl chloride in particular, when a photocatalyst is supported on the tent for the purpose of antifouling, anti-algae, etc., the tent is degraded by the photocatalytic action.
  • a synthetic resin such as vinyl chloride
  • Patent Document 6 proposes a structure in which an adhesive layer made of a silicon-modified resin, a resin containing polysiloxane, or a resin containing colloidal silica is provided between a photocatalyst layer and a tent.
  • an adhesive layer made of a silicon-modified resin, a resin containing polysiloxane, or a resin containing colloidal silica is provided between a photocatalyst layer and a tent.
  • a tent ground supporting a photocatalyst or a tent ground further using the above-mentioned metal or a compound thereof it has been difficult to provide a long-term anti-algal property.
  • the object of the present invention is to provide a photocatalyst supporting structure in which a photocatalyst layer is provided on the surface of a base material, in particular, a photocatalyst supporting structure excellent in both antialgal activity and NOx decomposition activity.
  • the present inventors provide a method for manufacturing a photocatalyst-supporting structure in which a coating solution for forming a photocatalyst layer containing a photocatalyst dispersion liquid is applied onto a substrate, wherein a photocatalyst dispersion liquid having a pH of 8 to 11 is used.
  • the inventors have found that a structure that solves the above-mentioned problems can be obtained by using a conductive zinc oxide in which other elements are dissolved in a coating solution for use in combination, and have completed the present invention.
  • the present invention relates to the invention having the following aspects.
  • Component (A) zinc oxide particles in which other elements are dissolved
  • component (B) photocatalyst particles other than (A)
  • component (C) binder other than (A) and (B)
  • a component (D) an aqueous dispersion medium, and has a pH of 7.5 to 11, and is a coating solution for forming a photocatalyst layer.
  • a method for producing a photocatalyst-carrying structure comprising a step of applying the photocatalyst layer-forming coating liquid according to any one of (1) to (6) to at least a part of the surface of a substrate, and drying.
  • a photocatalyst supporting structure comprising: (11) The photocatalyst supporting structure according to (10), further including an adhesive layer between the base material and the photocatalyst layer.
  • a photocatalyst-supporting structure having both excellent antialgal activity and excellent NOx decomposition activity can be obtained.
  • the coating solution for forming a photocatalyst layer of the present invention comprises: component (A): zinc oxide particles in which another element is dissolved in solid form; component (B): photocatalyst particles other than (A); and component (C): (A). And (B) and a component (D): an aqueous dispersion medium, and has a pH of 7.5 to 11, and is a coating solution for forming a photocatalyst layer.
  • the coating solution for forming an alkaline photocatalyst layer using an alkaline photocatalyst dispersion as a material was found to be superior in algal protection activity as compared with the coating solution for forming an acidic photocatalyst by itself. It has been found that the use of a combination exhibits a further anti-algal effect. On the other hand, the coating solution for forming an acidic photocatalyst layer has poor antialgal activity even when a metal such as zinc or a compound thereof is used in combination, but the remarkable antialgal activity is obtained when zinc oxide is used in combination for the coating solution for forming an alkaline photocatalytic layer. was gotten.
  • the mixing ratio of each component in the photocatalyst layer forming coating liquid of the present invention is in the following range.
  • the mixing ratio of the component (A) is preferably 0.05 to 2 parts by mass with respect to 1 part by mass of the component (B).
  • the coating solution for forming a photocatalyst layer of the present invention contains, as an essential component, zinc oxide particles in which another element is dissolved as a component (A).
  • “Other elements are in solid solution” means that the other elements are uniformly dispersed and present in at least a part of the solid matrix containing zinc oxide as a main component. Includes a form in which the compound and zinc oxide are present independently and form a complex (for example, the former covers the surface of the latter, or the fine particles of the former are carried on the latter). do not do.
  • a peak characteristic of the zinc oxide crystal be detected by powder X-ray diffraction.
  • the content of the other element in the zinc oxide is not necessarily limited, but the content of the other element with respect to the zinc oxide is preferably 0.001 to 20% by mass, more preferably 0.01 to 10% by mass. .
  • a synergistic anti-algal activity is obtained by a combination of a photocatalyst and such zinc oxide under alkaline conditions.
  • An article containing a metal such as silver or copper may be discolored, and this tends to be a problem particularly when used in combination with a photocatalyst and used outdoors where strong ultraviolet light is present.
  • zinc oxide has no fear of causing such discoloration, and is particularly suitable for use in tents and exterior materials.
  • Zinc oxide also has low toxicity and adverse effects on the environment, and is also superior to other metals or compounds thereof in this respect. It is already known that the combined use of a photocatalytic material and an amphoteric metal oxide promotes NOx decomposition, and this may also contribute to the NOx decomposition effect according to the present invention. However, the use of zinc oxide containing another element as a solid solution further enhances the NOx decomposition effect. This effect was first revealed this time.
  • the zinc oxide used as a raw material of the coating solution for forming a photocatalyst of the present invention may be a powder without any problem as long as it can be uniformly dispersed in the coating solution for forming a photocatalyst layer at least during coating.
  • a dispersion liquid dispersed in a dispersion medium may be used.
  • the pH of the coating solution for forming a photocatalyst layer needs to be 7.5 to 11, so that the dispersion is preferably neutral or alkaline, and preferably has a pH of 7 to 11.
  • the particle size of zinc oxide is not particularly limited, but the average particle size is preferably from 5 to 100 nm, particularly preferably from 10 to 50 nm.
  • the other element contained in zinc oxide used as a raw material of the photocatalyst-forming coating liquid of the present invention is an element other than zinc and oxygen, and is not necessarily limited, but is a positive element, particularly a positive element having a valence of 4 or less.
  • Preferred are Group 1 element, Group 2 element, transition metal (Group 3 to Group 11) element, Group 13 element, Group 14 element and the like.
  • Specific examples thereof include hydrogen, lithium, sodium, potassium, beryllium, magnesium, calcium, scandium, yttrium, lanthanum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt,
  • Examples include nickel, palladium, copper, silver, boron, aluminum, gallium, indium, silicon, germanium, tin, and the like. Among them, a trivalent element or a group 13 element is more preferable.
  • the trivalent element is an element that exists as a trivalent oxidation state in a state of being contained in a solid solution in zinc oxide, and includes, for example, iron and the like in addition to the group 13 element.
  • group 13 elements include boron, aluminum, gallium, indium and the like. Of the above elements, aluminum or gallium is particularly preferred.
  • zinc oxide in which these elements are dissolved those generally sold as conductive zinc oxide may be used.
  • the coating solution for forming a photocatalyst layer of the present invention contains, as an essential component, photocatalyst particles other than the component (A) as the component (B).
  • the photocatalyst particles have such a particle size that the photocatalyst material can be dispersed in the photocatalyst layer forming coating solution.
  • the photocatalyst material used in the present invention is an inorganic material comprising a component other than the component (A), preferably a component other than zinc oxide, and containing a metal oxide having photocatalytic activity.
  • the main components of the photocatalytic material include titanium oxide, strontium titanate, tin oxide, zirconium oxide, tungsten oxide, chromium oxide, molybdenum oxide, iron oxide, nickel oxide, ruthenium oxide, vanadium oxide, niobium oxide, and tantalum oxide. , Rhodium oxide, rhenium oxide and the like.
  • titanium oxide, strontium titanate, tungsten oxide and the like are preferable, and anatase type or rutile type titanium oxide is particularly preferable.
  • the particle size of the photocatalyst material fine particles is not particularly limited, but the average particle size is preferably 5 to 100 nm, and particularly preferably 10 to 50 nm.
  • Powder may be used for the photocatalyst particles as a raw material of the coating solution for photocatalyst formation of the present invention, but it is preferable to use a photocatalyst dispersion liquid in which the photocatalyst particles are dispersed in a dispersion medium in advance.
  • a photocatalyst dispersion liquid in general, an aqueous dispersion medium which is acidic or alkaline and is dispersed in an aqueous dispersion medium is used in order to stably disperse the dispersion under the effect of the surface potential.
  • An acidic or neutral photocatalyst dispersion may be used for the coating solution for forming a photocatalyst layer of the present invention, but in this case, a step of finally adjusting the pH to 7.5 to 11 is required. There is a risk that the sex may be affected. On the other hand, it is preferable to use a photocatalyst dispersion having a pH of 8 to 11, since this pH adjustment step is unnecessary. It is preferable that the content of the photocatalyst as the component (B) is 5% by mass to 60% by mass in terms of oxide based on the entire photocatalyst layer. When the content is less than 5% by mass, the photocatalytic activity of the photocatalyst layer is significantly reduced.
  • the photocatalytic activity becomes high, but the adhesion between the photocatalyst layer and the substrate or the adhesive layer becomes poor.
  • Component (A) may also have photocatalytic activity, but its photocatalytic activity is relatively low, and the adverse effect of component (A) on adhesion to a substrate or an adhesive layer is small. Therefore, the total content of the component (A) and the component (B) (in terms of oxide) may be higher than the upper limit of the content of the component (B) alone, and may be 10% by mass to 90% by mass with respect to the entire photocatalyst layer. % By mass, and more preferably from 20% by mass to 60% by mass.
  • the coating solution for forming a photocatalyst layer of the present invention further contains a binder other than (A) and (B) as component (C).
  • the purpose of the binder is to fix the photocatalyst powder and firmly adhere to the substrate or the adhesive layer.
  • the binder used in the present invention preferably contains one or more of a metal oxide or a metal hydroxide other than the photocatalyst and zinc oxide. More preferably, it is derived from a liquid.
  • the dispersion of the metal oxide or the metal hydroxide becomes a metal oxide gel or a hydroxide gel in the photocatalyst layer when the photocatalyst layer coated with the photocatalyst layer forming coating solution is dried, and the photocatalyst powder is fixed.
  • the metal component include oxide gels or hydroxide gels of metals such as silicon, aluminum, titanium, zirconium, magnesium, niobium, tantalum, tungsten, and tin (excluding those that are photocatalysts). .
  • a silica dispersion or an alumina dispersion is preferred, and a silica dispersion is particularly preferred.
  • the dispersion of the metal oxide or the metal hydroxide may contain an acid or an alkali as a deflocculant in order to ensure the stability of the dispersion.
  • the pH of the coating solution for forming the photocatalyst layer needs to be 7.5 to 11
  • the dispersion of the metal oxide or metal hydroxide is preferably neutral or alkaline, and has a pH of 7 to 11. Is particularly preferred.
  • a resin, a hydrolyzable silane compound or a partial hydrolysis condensate thereof, or a metal oxide or a metal hydroxide precursor examples include a silicone resin, a silicone-modified resin, and a fluororesin that are not easily deteriorated by a photocatalytic action.
  • the silicone-modified resin examples include an acrylic silicone resin and an epoxy silicone resin.
  • the hydrolyzable silane compound has the general structural formula R n SiX (4-n) (where R is a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or X represents an optionally substituted aryl group, and X represents a chlorine atom, an optionally substituted alkoxy group, an optionally substituted alkenyloxy group, or an optionally substituted substituent. Represents an aryloxy group, and n represents an integer of any of 0 to 3.)
  • the partially hydrolyzed condensate of a hydrolyzable silane compound is a compound obtained by hydrolyzing and condensing one or more of the above hydrolyzable silane compounds.
  • a precursor of a metal oxide or a metal hydroxide means a substance that is converted to a metal oxide or a metal hydroxide by hydrolysis, and specifically, an alkoxide containing the metal, Examples of the chelate compound and the like contained therein, more specifically, silane alkoxide, aluminum alkoxide, aluminum chelate compound, titanium alkoxide, titanium chelate compound, zirconium alkoxide, zirconium chelate compound, and the like.
  • These are hydrolyzed by using an alkali component contained in the photocatalyst dispersion used in the photocatalyst layer forming coating solution of the present invention as a catalyst, or the hydrolysis can be promoted by heating after coating.
  • the photocatalyst layer-forming coating liquid of the present invention contains an aqueous dispersion medium.
  • the dispersion medium is preferably an aqueous dispersion medium composed of water or a solution containing water and an organic solvent miscible with water.
  • a photocatalyst dispersion liquid a dispersion medium previously contained in a dispersion liquid of a metal oxide or a metal hydroxide as a binder may be used as it is, or the solid content concentration may be adjusted or as described below.
  • water and / or an organic solvent may be added.
  • an aqueous dispersion medium composed of a solution containing water and a volatile organic solvent is preferable because it has excellent wettability during coating and is easy to dry after coating.
  • the organic solvent lower alcohols such as methanol, ethanol, n-propanol, isopropanol and n-butanol are preferable.
  • the concentration of the organic solvent is preferably from 10 to 80% by mass, more preferably from 30 to 60% by mass. As described above, a uniform photocatalyst layer can be formed without inconveniences such as repelling at the time of coating and scraping of the adhesive layer.
  • the coating solution for forming a photocatalyst layer of the present invention contains a pH adjuster, a dispersant, a surfactant, a thickener, a dye, and the like, in addition to the components described above, as long as the effects of the present invention are not reduced. You may.
  • the production of the coating solution for forming a photocatalyst layer according to the present invention may basically be performed by mixing the above-mentioned raw materials to make them uniform, and the mixing order is not particularly limited. However, when the pH or the concentration of the organic solvent fluctuates greatly due to the mixing, in order to prevent aggregation and gelation of particles due to the influence, an order that can avoid such fluctuations is adopted. It is preferable to employ a method of gradually mixing the mixture by dripping into the other material.
  • the photocatalyst-supporting structure of the present invention is a structure including a base material and a photocatalyst layer adhered to at least a part of the surface of the base material, and the photocatalyst layer is a coating for forming a photocatalyst layer of the present invention. It is characterized by being a dried solidified liquid.
  • the substrate is not particularly limited, and examples thereof include metals, ceramics, ceramics, stones, cement, concrete, glass, plastic, wood, synthetic resins, synthetic fibers, natural fibers, tents, and composite materials obtained by combining them. be able to.
  • As the shape of the substrate any complicated shape such as a film, a sheet, a plate, a tube, a fiber, and a net can be used.
  • the thickness of the substrate is preferably 10 ⁇ m or more because it can be firmly supported.
  • the photocatalyst layer in the photocatalyst supporting structure of the present invention can be manufactured by applying the coating solution for forming a photocatalyst layer of the present invention to at least a part of the surface of a substrate, and drying and solidifying this.
  • Spray coating, spin coating, bar coating, roller coating, brush coating, screen printing, gravure coating, and the like can be used as a coating method, and a dip method (dipping method) when coating the entire surface of the substrate. May be used.
  • the drying and solidification steps may be performed at room temperature, but may be heated to promote drying and solidification.
  • the substrate may be preheated.
  • the conditions for this heating are not necessarily limited, but it is preferable to perform the heating within a temperature and time range in which deformation or deterioration of the substrate does not occur.
  • the temperature is preferably set to 200 ° C. or lower, which is particularly suitable when the substrate contains a non-heat-resistant synthetic resin.
  • the non-heat-resistant synthetic resin is a synthetic resin that deforms at 160 ° C., and includes a vinyl chloride resin, an acrylic resin, a styrene resin, an olefin resin, and a composite resin composed of these.
  • the temperature may be higher than such a deformation temperature, but in such a case, it is preferable to keep the temperature and time within a range in which the deformation of the substrate does not occur.
  • the thickness of the photocatalyst layer is not particularly limited, but the thicker the photocatalytic activity. However, when the thickness exceeds 5 ⁇ m, the activity hardly changes. When the thickness is less than 0.1 ⁇ m, although the translucency is improved, high activity cannot be expected because ultraviolet light used by the photocatalyst is transmitted. For this reason, the range is usually preferably from 0.1 to 5 ⁇ m, more preferably from 0.5 to 5 ⁇ m.
  • One or more adhesive layers may be further provided between the substrate and the photocatalyst layer.
  • the adhesive layers may be further provided between the substrate and the photocatalyst layer.
  • the material of the adhesive layer is not particularly limited as long as it can protect the base material from deterioration due to the photocatalytic action and can firmly fix the photocatalytic layer.
  • the silicone content is converted to oxide.
  • a silicone-modified resin such as an acrylic silicone resin, an epoxy silicone resin, or a polyester silicone resin, which is 2 to 60% by mass; (2) a resin containing 3 to 90% by mass of a polysiloxane in terms of oxide; ) A resin containing 5 to 90% by mass of colloidal silica in terms of oxide can be used. These resins firmly adhere to the photocatalyst, are suitable for protecting the substrate from the photocatalyst, and can prevent the diffusion of the plasticizer and other components to the surface when the substrate contains a component such as a plasticizer.
  • Silicone-modified resins such as acrylic silicone resin having a silicone content of less than 2% by mass in terms of oxides, resins having a polysiloxane content of less than 3% by mass in terms of oxides, and colloidal silica contents having an oxide content
  • the amount of the resin is less than 5% by mass, adhesion to the photocatalyst layer is deteriorated, and the adhesion layer is deteriorated by the photocatalyst, and the photocatalyst layer is easily peeled.
  • Silicone-modified resins such as acrylic silicone resin whose silicone content exceeds 10% by mass in terms of oxides, resins whose polysiloxane content exceeds 90% by mass in terms of oxides, and colloidal silica content in which oxides exist If the resin exceeds 90% by mass, the adhesion to the substrate is reduced.
  • the resin into which silicone is introduced include an acrylic resin, an epoxy resin, a polyester resin, an alkyd resin, and a urethane resin. Among them, acrylic resin, epoxy resin and polyester resin are particularly preferable in view of film formability, toughness, and adhesion to a carrier. These resins can be used in either a solution state or an emulsion type. Further, additives such as a crosslinking agent may be contained.
  • the polysiloxane contained in the resin of the adhesive layer is a hydrolyzate of a silane alkoxide having an alkoxy group having 1 to 5 carbon atoms or a product of the hydrolyzate
  • a carrier having improved adhesion and durability is provided.
  • a structure can be obtained.
  • the number of carbon atoms of the alkoxy group of the silane alkoxide exceeds 6, the hydrolysis rate is extremely slow, so that it is difficult to cure the resin in a resin, and the adhesiveness and durability deteriorate.
  • a polysiloxane obtained by hydrolyzing a silane alkoxide partially containing chlorine can be used.However, when a polysiloxane containing a large amount of chlorine is used, the base material is corroded by chlorine ions as impurities. Or the adhesiveness may be reduced.
  • the adhesive layer is obtained by applying an adhesive layer coating solution containing the above components or a precursor thereof to the surface of the substrate, drying and solidifying. This method may be selected according to the composition of the adhesive layer coating solution, but can be performed in the same manner as that of the photocatalyst layer.
  • the thickness of the adhesive layer is not particularly limited, but is usually preferably in the range of 0.1 to 10 ⁇ m, more preferably in the range of 0.5 to 5 ⁇ m. Further, in order to improve the adhesion between the base material and the adhesive layer, a base material whose surface has been subjected to an easy adhesion treatment such as a discharge treatment or a primer treatment may be used.
  • the environment in which the photocatalyst-supporting structure of the present invention is used is not particularly limited as long as it is irradiated with light, but is irradiated with external light including ultraviolet light (the shade may be protected from direct sunlight) and algae. It is preferable to use in an outdoor environment where the occurrence of odor can occur. Although it can be used in water, zinc elutes and tends to decrease in environments that are in constant contact with water, so it is preferable to use it in environments other than those that are in constant contact with water, such as precipitation, watering, It is particularly preferable to use it in an environment where the surface of the structure is temporarily washed off by temporary contact with water due to dew condensation or the like.
  • exterior materials for buildings such as resin-based siding, ceramic-based siding, and tiles, outer walls constructed by in-situ coating with fluorine paint, acrylic silicone paint, etc., and wooden decks installed outdoors (made of wood or wood-plastic composite ) And tents. It is also preferable to use it in an environment along a road with a large amount of nitrogen oxides, and it is particularly preferable to use it in a signboard or a road sign because it has the effect of preventing surface contamination.
  • a white tent was used as a substrate.
  • the acrylic silicone resin was diluted with a mixed solvent of ethanol-butanol-ethyl acetate to a solid content concentration of 20% by mass to obtain a coating solution for forming an adhesive layer.
  • the coating liquid for forming an adhesive layer was applied once to one surface of the substrate by bar coating and dried at 100 ° C. for 5 minutes to form an adhesive layer having a thickness of about 1.0 ⁇ m.
  • Example 1 The silica was suspended in sodium hydroxide and pulverized with a bead mill to obtain an alkaline silica sol having a particle diameter of 4 to 6 nm, a solid content of 20% by mass, and a pH of 9. 575 g of a 13% by mass aqueous solution of ammonium hydrogen carbonate was added to 2950 g of an aqueous dispersion of the reagent zinc oxide (average particle size: 1.0 ⁇ m, 5% by mass), stirred at room temperature, and then heated to 70 ° C. and further 30 minutes By aging, an aqueous dispersion of basic zinc carbonate was obtained.
  • Example 1 A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that the aluminum-doped zinc oxide was not used.
  • Example 2 A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that nickel powder (primary particle size: 0.5 to 50 ⁇ m) was used instead of aluminum-doped zinc oxide.
  • Example 3 A coating solution for forming a photocatalyst in the same manner as in Example 1 except that cupronickel powder (an alloy composed of 70% by mass of copper and 30% by mass of nickel, primary particle size of 40 to 50 ⁇ m) was used instead of aluminum-doped zinc oxide. I got
  • Example 4 A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that a reagent zinc oxide (average particle size: 1.0 ⁇ m) was used instead of aluminum-doped zinc oxide.
  • Comparative Example 5 A photocatalyst for forming a photocatalyst was prepared in the same manner as in Comparative Example 1, except that the aqueous dispersion of the aluminum-doped zinc oxide powder used in Example 1 (solid content concentration: 40% by mass, pH 8.5) was used instead of the alkaline titanium dioxide sol. A coating solution was obtained.
  • NOx removal test Using the photocatalyst-carrying structure (Example 1; Comparative Examples 1, 2, 4, and 5) obtained by the above method, evaluation of the NOx decomposition function by light irradiation was performed. The evaluation of the NOx decomposition function is described in "JIS R 1701-1: 2010 Fine Ceramics-Test Method for Air Purification Performance of Photocatalyst Material-Part 1: Removal Performance of Nitrogen Oxide""Test Method for Specimen with Small Removal” , The amount of NOx removed per test piece was measured. The results were as shown in Table 2.

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Abstract

The purpose of the present invention is to provide a photocatalyst supporting structure having a photocatalyst layer on the surface of a substrate, in particular, a photocatalyst carrier structure having excellent anti-algal activity and NOx decomposition activity. A coating liquid for forming the photocatalyst layer contains the following components: zinc oxide particles (A) in which another element is solid-solved; photocatalyst particles (B) other than the component (A); a binder (C) other than the components (A) and (B); and an aqueous dispersion (D). The coating liquid for forming the photocatalyst layer has a pH of 7.5-11. The other element in the component (A) is preferably an electropositive element having a valence of four or less or an element of Group 13.

Description

光触媒担持構造体及びその製造方法Photocatalyst carrying structure and method for producing the same
　本発明は、光触媒担持構造体、それを形成するための塗布液、及び該構造体の製造方法に関し、また該構造体により藻類の生育又は繁殖を抑制する方法、及び窒素酸化物を分解除去する方法に関する。本願は、２０１８年９月３日に出願された日本国特許出願第２０１８－１６４７８８号に対し優先権を主張し、その内容をここに援用する。 The present invention relates to a photocatalyst-supporting structure, a coating solution for forming the same, and a method for producing the structure, and a method for suppressing the growth or propagation of algae by the structure, and decomposing and removing nitrogen oxides. About the method. This application claims priority to Japanese Patent Application No. 2018-164788 filed on September 3, 2018, the content of which is incorporated herein by reference.
　光触媒材料は、建築物の外装材等の材料において、その表面に担持させることにより、汚れを落ち易くし、あるいは細菌、かび、藻類等の微生物の生育や繁殖を抑制するために利用されている。またこのような材料で窒素酸化物（ＮＯｘ）等の大気汚染物質を分解により除去し大気を浄化する効果も知られている。
　藻類等の微生物の生育や繁殖を抑制する効果を得ようとする場合、光触媒材料を単独の活性成分として使用しても十分でないことがある。この原因としては、光触媒材料は超親水性を示し、表面が保湿されやすいことが考えられる。そこで、それ自体でも微生物防除活性を有する銀、銅等の金属又はその化合物を併用することが提案されている（特許文献１等）。しかしこれらは、屋外においては有効成分の溶出により効果の持続性に乏しいことがある。またこれらの金属化合物による変色が問題となる場合もある。
　一方、水中で防藻効果を得るための組成物では、酸化亜鉛等の亜鉛化合物を含有するものが知られている（特許文献２等）。
　酸化亜鉛は、微生物防除や消臭の目的のほか、顔料、塗料等の填料、医薬品、化粧品成分、紫外線遮蔽剤、帯電防止剤、半導体材料等として広く用いられている。特にアルミニウム、ガリウム等の他元素がドープされた酸化亜鉛は、導電性に優れ、かつ熱線遮蔽効果も有し、これらの効果を目的として多く用いられている（特許文献３等）。
　特許文献４には、光触媒材料と両性金属酸化物との併用により、優れたＮＯｘ分解効果を発揮する光触媒配合物が記載されている。具体例な使用例としては、タイル表面に該配合物を塗布し熱処理で固定している。また抗菌性を有する態様も記載されているが、それは追加成分として引用文献１等と同様の金属又はその化合物を含有することでその効果を発揮し得るものであり、上記の欠点を回避できるものではない。
　また特許文献５には、２種類の光触媒として、多孔質酸化チタンと、貴金属担持酸化亜鉛粒子とを含有する光触媒材料に関して、光照射によりＮＯｘを分解することが記載されている。
　テント地は屋外に長期的に設けられる構造物にも使用されており、環境によっては外装材と同様に藻類の生育や繁殖が問題となる。一方、特にＢ種又はＣ種のテント地は塩化ビニル等の合成樹脂を含むことから、これに防汚、防藻等の目的で光触媒を担持させる場合には、光触媒作用によりテント地が劣化したり、光触媒層が剥離したり、あるいは樹脂中に含まれる可塑剤が表面に拡散することで光触媒活性を阻害するといった問題点があった。これらを解決するために、例えば特許文献６では、光触媒層とテント地との間に、シリコン変性樹脂、ポリシロキサン含有樹脂、又はコロイダルシリカを含有する樹脂からなる接着層を設けた構造が提案され、実用化されている。しかしこのような光触媒担持テント地、あるいはさらに上記のような金属又はその化合物を併用したテント地でも、長期に亘る防藻性を付与することは困難であった。 Photocatalytic materials are used for facilitating the removal of dirt or supporting the growth and propagation of microorganisms such as bacteria, molds and algae by supporting them on the surface of materials such as exterior materials of buildings. . It is also known that such materials are effective in purifying the atmosphere by removing air pollutants such as nitrogen oxides (NOx) by decomposition.
In order to obtain the effect of suppressing the growth and propagation of microorganisms such as algae, it may not be sufficient to use a photocatalytic material as a sole active ingredient. This may be because the photocatalytic material is super-hydrophilic and the surface is easily moisturized. Accordingly, it has been proposed to use a metal such as silver or copper or a compound thereof having a microbial control activity by itself (Patent Document 1 and the like). However, these may be poor in persistence of the effect outdoors due to elution of the active ingredient. In addition, discoloration by these metal compounds may be a problem.
On the other hand, a composition containing a zinc compound such as zinc oxide is known as a composition for obtaining an anti-algal effect in water (Patent Document 2 and the like).
Zinc oxide has been widely used as a filler for pigments and paints, pharmaceuticals, cosmetic ingredients, ultraviolet shielding agents, antistatic agents, semiconductor materials, and the like, in addition to the purpose of controlling microorganisms and deodorizing. In particular, zinc oxide doped with other elements such as aluminum and gallium has excellent conductivity and also has a heat ray shielding effect, and is often used for these effects (Patent Document 3 and the like).
Patent Literature 4 describes a photocatalyst formulation that exhibits an excellent NOx decomposition effect when used in combination with a photocatalyst material and an amphoteric metal oxide. As a specific example of use, the composition is applied to the tile surface and fixed by heat treatment. Although an embodiment having antibacterial properties is also described, it can exert its effect by containing the same metal or a compound thereof as in Patent Document 1 or the like as an additional component, and can avoid the above-mentioned disadvantages. is not.
Patent Literature 5 describes that a photocatalytic material containing two types of photocatalysts, porous titanium oxide and noble metal-supported zinc oxide particles, decomposes NOx by light irradiation.
Tent grounds are also used for structures that are provided outdoors for a long period of time, and depending on the environment, the growth and propagation of algae may become a problem, as in the case of exterior materials. On the other hand, since tents of type B or C contain a synthetic resin such as vinyl chloride in particular, when a photocatalyst is supported on the tent for the purpose of antifouling, anti-algae, etc., the tent is degraded by the photocatalytic action. There is a problem that the photocatalyst layer is peeled off, or the plasticizer contained in the resin diffuses to the surface to inhibit the photocatalytic activity. In order to solve these problems, for example, Patent Document 6 proposes a structure in which an adhesive layer made of a silicon-modified resin, a resin containing polysiloxane, or a resin containing colloidal silica is provided between a photocatalyst layer and a tent. Has been put to practical use. However, even in such a tent ground supporting a photocatalyst or a tent ground further using the above-mentioned metal or a compound thereof, it has been difficult to provide a long-term anti-algal property.
特許第６２８３９２２号公報Japanese Patent No. 6283922 特開平６－４８９０９号公報JP-A-6-48909 特開２００１－２２２９１１号公報JP 2001-222911 A 特開平１１－１９２４３６号公報JP-A-11-192436 特開２００７－２２９６２４号公報JP 2007-229624 A 特開平１０－２３７７６９号公報Japanese Patent Application Laid-Open No. Hei 10-2337769
　本願発明は、基材の表面に光触媒層を設けた光触媒担持構造体において、特に防藻活性とＮＯｘ分解活性とが共に優れた光触媒担持構造体を提供することを目的とする。 The object of the present invention is to provide a photocatalyst supporting structure in which a photocatalyst layer is provided on the surface of a base material, in particular, a photocatalyst supporting structure excellent in both antialgal activity and NOx decomposition activity.
　本発明者らは、光触媒分散液を含有する光触媒層形成用塗布液を基材上に塗布する光触媒担持構造体の製造方法において、光触媒分散液としてｐＨ８～１１のものを用い、かつ光触媒層形成用塗布液に他元素が固溶している導電性酸化亜鉛を併用することにより、上記諸課題を解決した構造体が得られることを見出し、本発明を完成するに至った。 The present inventors provide a method for manufacturing a photocatalyst-supporting structure in which a coating solution for forming a photocatalyst layer containing a photocatalyst dispersion liquid is applied onto a substrate, wherein a photocatalyst dispersion liquid having a pH of 8 to 11 is used. The inventors have found that a structure that solves the above-mentioned problems can be obtained by using a conductive zinc oxide in which other elements are dissolved in a coating solution for use in combination, and have completed the present invention.
　すなわち、本発明は、以下の態様を有する発明に関する。
（１）成分（Ａ）：他元素が固溶している酸化亜鉛粒子と、成分（Ｂ）：（Ａ）以外の光触媒粒子と、成分（Ｃ）：（Ａ）及び（Ｂ）以外のバインダーと、成分（Ｄ）：水性分散媒とを含有し、ｐＨが７．５～１１である、光触媒層形成用塗布液。
（２）成分（Ａ）における他元素が、４価以下の陽性元素である、（１）に記載の光触媒層形成用塗布液。
（３）成分（Ａ）における他元素が、１３族元素である、（１）に記載の光触媒層形成用塗布液。
（４）成分（Ｂ）が酸化チタン粒子である、（１）～（３）のいずれかに記載の光触媒形成用塗布液。
（５）成分（Ｂ）が、光触媒層形成用塗布液の原料としての光触媒分散液に由来し、該分散液のｐＨが８～１１である、（１）～（４）のいずれかに記載の光触媒層形成用塗布液。
（６）成分（Ｃ）が、金属酸化物及び金属水酸化物から成る群から選択される少なくとも１種である、（１）～（５）のいずれかに記載の光触媒層形成用塗布液。
（７）基材表面の少なくとも一部に、（１）～（６）のいずれかに記載の光触媒層形成用塗布液を塗布し、乾燥する工程を含む、光触媒担持構造体の製造方法。
（８）基材表面の光触媒層形成用塗布液を塗布する部分に、予め接着層が設けられている、（７）に記載の光触媒担持構造体の製造方法。
（９）前記乾燥工程における温度が２００℃以下である、（７）又は（８）に記載の光触媒担持構造体の製造方法。
（１０）基材と、該基材の表面の少なくとも一部に被着された、（１）～（６）のいずれかに記載の光触媒層形成用塗布液の乾燥固化物からなる光触媒層とを含む、光触媒担持構造体。
（１１）前記基材と、前記光触媒層との間に、接着層を含む、（１０）に記載の光触媒担持構造体。
（１２）基材が非耐熱性合成樹脂を含む、（１０）又は（１１）に記載の光触媒担持構造体。
（１３）テント地である、（１０）～（１２）のいずれかに記載の光触媒担持構造体。
（１４）（１０）～（１３）のいずれかに記載の光触媒担持構造体により藻類の生育及び／又は繁殖を抑制する方法。
（１５）（１０）～（１３）のいずれかに記載の光触媒担持構造体により窒素酸化物を分解及び／又は除去する方法。　　 That is, the present invention relates to the invention having the following aspects.
(1) Component (A): zinc oxide particles in which other elements are dissolved, component (B): photocatalyst particles other than (A), and component (C): binder other than (A) and (B) And a component (D): an aqueous dispersion medium, and has a pH of 7.5 to 11, and is a coating solution for forming a photocatalyst layer.
(2) The coating solution for forming a photocatalyst layer according to (1), wherein the other element in the component (A) is a positive element having a valence of 4 or less.
(3) The coating liquid for forming a photocatalyst layer according to (1), wherein the other element in the component (A) is a Group 13 element.
(4) The coating solution for forming a photocatalyst according to any one of (1) to (3), wherein the component (B) is a titanium oxide particle.
(5) The component according to any one of (1) to (4), wherein the component (B) is derived from a photocatalyst dispersion as a raw material of a coating solution for forming a photocatalyst layer, and the dispersion has a pH of 8 to 11. Coating solution for forming a photocatalyst layer.
(6) The coating solution for forming a photocatalyst layer according to any one of (1) to (5), wherein the component (C) is at least one selected from the group consisting of metal oxides and metal hydroxides.
(7) A method for producing a photocatalyst-carrying structure, comprising a step of applying the photocatalyst layer-forming coating liquid according to any one of (1) to (6) to at least a part of the surface of a substrate, and drying.
(8) The method for producing a photocatalyst-supporting structure according to (7), wherein an adhesive layer is provided in advance on a portion of the surface of the base material to which the coating solution for forming a photocatalyst layer is applied.
(9) The method for producing a photocatalyst-supporting structure according to (7) or (8), wherein the temperature in the drying step is 200 ° C or less.
(10) A base material, and a photocatalyst layer formed of a dried and solidified product of the coating solution for forming a photocatalyst layer according to any one of (1) to (6), which is applied to at least a part of the surface of the base material. A photocatalyst supporting structure, comprising:
(11) The photocatalyst supporting structure according to (10), further including an adhesive layer between the base material and the photocatalyst layer.
(12) The photocatalyst supporting structure according to (10) or (11), wherein the base material contains a non-heat-resistant synthetic resin.
(13) The photocatalyst-supporting structure according to any one of (10) to (12), which is a tent site.
(14) A method for suppressing the growth and / or reproduction of algae by the photocatalyst-supporting structure according to any one of (10) to (13).
(15) A method for decomposing and / or removing nitrogen oxides by the photocatalyst-supporting structure according to any one of (10) to (13).
　本発明により、防藻活性とＮＯｘ分解活性とが共に優れた光触媒担持構造体が得られる。 According to the present invention, a photocatalyst-supporting structure having both excellent antialgal activity and excellent NOx decomposition activity can be obtained.
（光触媒層形成用塗布液）
　本発明の光触媒層形成用塗布液は、成分（Ａ）：他元素が固溶している酸化亜鉛粒子と、成分（Ｂ）：（Ａ）以外の光触媒粒子と、成分（Ｃ）：（Ａ）及び（Ｂ）以外のバインダーと、成分（Ｄ）：水性分散媒とを含有し、ｐＨが７．５～１１である、光触媒層形成用塗布液である。
　アルカリ性光触媒分散液を材料として用いたアルカリ性光触媒層形成塗布液は、それ自体でも酸性の光触媒形成用塗布液と比較して、防藻活性が優れることが明らかとなったが、それに加え、酸化亜鉛を併用することで、さらなる防藻効果を発現することを見出した。一方、酸性光触媒層形成用塗布液は、たとえ亜鉛等の金属又はその化合物を併用しても防藻活性は乏しいが、アルカリ性光触媒層形成用塗布液に酸化亜鉛を併用すれば顕著な防藻活性が得られた。この理由は明確ではないが、アルカリ性塗布液から形成された光触媒塗膜の表面電位が負となることで負電荷を有する藻の吸着が抑制されること、酸化亜鉛自体の防藻効果、さらに金属成分の溶出が防止されることにより金属成分による防藻効果が持続すること等が相乗的に寄与していると思われる。 (Coating solution for forming photocatalyst layer)
The coating solution for forming a photocatalyst layer of the present invention comprises: component (A): zinc oxide particles in which another element is dissolved in solid form; component (B): photocatalyst particles other than (A); and component (C): (A). And (B) and a component (D): an aqueous dispersion medium, and has a pH of 7.5 to 11, and is a coating solution for forming a photocatalyst layer.
The coating solution for forming an alkaline photocatalyst layer using an alkaline photocatalyst dispersion as a material was found to be superior in algal protection activity as compared with the coating solution for forming an acidic photocatalyst by itself. It has been found that the use of a combination exhibits a further anti-algal effect. On the other hand, the coating solution for forming an acidic photocatalyst layer has poor antialgal activity even when a metal such as zinc or a compound thereof is used in combination, but the remarkable antialgal activity is obtained when zinc oxide is used in combination for the coating solution for forming an alkaline photocatalytic layer. was gotten. Although the reason is not clear, the adsorption of algae having a negative charge is suppressed by the negative surface potential of the photocatalytic coating film formed from the alkaline coating solution, the anti-algal effect of zinc oxide itself, and the metal It is thought that the prevention of elution of the components contributes synergistically to the sustaining of the anti-algal effect by the metal components.
　本発明の光触媒層形成用塗布液中の各成分の配合割合は、以下の範囲である。
成分（Ａ）：　０．０１～１０質量％、好ましくは０．１～５．０質量％
成分（Ｂ）：　０．１～１５質量％、好ましくは１．０～５．０質量％
成分（Ｃ）：　０．０１～１５質量％、好ましくは０．１～５．０質量％
成分（Ｄ）：　８０～９９質量％、好ましくは８５～９５質量％
　また、成分（Ｂ）１質量部に対して、成分（Ａ）の配合比は０．０５～２質量部であることが好ましい。　 The mixing ratio of each component in the photocatalyst layer forming coating liquid of the present invention is in the following range.
Component (A): 0.01 to 10% by mass, preferably 0.1 to 5.0% by mass
Component (B): 0.1 to 15% by mass, preferably 1.0 to 5.0% by mass
Component (C): 0.01 to 15% by mass, preferably 0.1 to 5.0% by mass
Component (D): 80 to 99% by mass, preferably 85 to 95% by mass
Further, the mixing ratio of the component (A) is preferably 0.05 to 2 parts by mass with respect to 1 part by mass of the component (B).
（酸化亜鉛）
　本発明の光触媒層形成用塗布液は、成分（Ａ）として、他元素が固溶している酸化亜鉛粒子を必須成分として含有する。
　「他元素が固溶している」とは、酸化亜鉛を主成分とする固体マトリックス中の少なくとも一部に他元素が均一に分散して存在していることを意味し、他元素の単体若しくは化合物と酸化亜鉛とが独立に存在し両者が複合体を形成している存在形態（例えば前者が後者の表面を被覆している、あるいは前者の微粒子が後者に担持されている等。）を包含しない。
　本粒子においては酸化亜鉛が主成分である限り問題はないが、粉末Ｘ線回折により酸化亜鉛結晶に特徴的なピークが検出されることが好ましい。酸化亜鉛中における他元素の含有量は必ずしも限定されないが、酸化亜鉛に対する他元素の含有量が０．００１～２０質量％であることが好ましく、０．０１～１０質量％であることがより好ましい。
　本発明では、アルカリ性条件下で、光触媒とこのような酸化亜鉛との組み合わせにより相乗的な防藻活性が得られる。
　銀、銅等の金属を含む物品は変色する場合があり、特に光触媒と併用し、紫外光の強い屋外で使用した場合には問題となりがちである。それに対して酸化亜鉛は、このような変色を起こす心配がなく、テントや外装材の用途には特に適している。なお、酸化亜鉛中の「他元素」としてこれらの金属が含有されていても、その含有量は微量でありかつ酸化亜鉛中に固溶して存在するため、問題はない。
　また酸化亜鉛は、毒性や環境に対する悪影響も低く、この点でもその他の金属又はその化合物に比較して優れている。
　光触媒材料と両性金属酸化物との併用によりＮＯｘ分解が促進されることが既に知られており、本発明によるＮＯｘ分解効果にもこれが寄与している可能性がある。しかし、他元素が固溶して含有される酸化亜鉛を用いると、ＮＯｘ分解効果がさらに増強される。この効果は今回初めて明らかにされたものである。
　本発明の光触媒形成用塗布液の原料として用いる酸化亜鉛は、少なくとも塗布時に光触媒層形成用塗布液中に均一に分散させることができるものであれば問題なく、粉末であってもよいし、予め分散媒に分散させてなる分散液でもよい。分散液である場合には、光触媒層形成用塗布液のｐＨが７．５～１１となる必要があるため、該分散液は中性ないしアルカリ性であることが好ましく、ｐＨ７～１１であることが特に好ましい。
　酸化亜鉛の粒子径は特に限定されないが、平均粒子径が、５～１００ｎｍであることが好ましく、１０～５０ｎｍであることが特に好ましい。 (Zinc oxide)
The coating solution for forming a photocatalyst layer of the present invention contains, as an essential component, zinc oxide particles in which another element is dissolved as a component (A).
"Other elements are in solid solution" means that the other elements are uniformly dispersed and present in at least a part of the solid matrix containing zinc oxide as a main component. Includes a form in which the compound and zinc oxide are present independently and form a complex (for example, the former covers the surface of the latter, or the fine particles of the former are carried on the latter). do not do.
Although there is no problem in the present particles as long as zinc oxide is the main component, it is preferable that a peak characteristic of the zinc oxide crystal be detected by powder X-ray diffraction. The content of the other element in the zinc oxide is not necessarily limited, but the content of the other element with respect to the zinc oxide is preferably 0.001 to 20% by mass, more preferably 0.01 to 10% by mass. .
In the present invention, a synergistic anti-algal activity is obtained by a combination of a photocatalyst and such zinc oxide under alkaline conditions.
An article containing a metal such as silver or copper may be discolored, and this tends to be a problem particularly when used in combination with a photocatalyst and used outdoors where strong ultraviolet light is present. On the other hand, zinc oxide has no fear of causing such discoloration, and is particularly suitable for use in tents and exterior materials. In addition, even if these metals are contained as “other elements” in zinc oxide, there is no problem because their contents are very small and exist as a solid solution in zinc oxide.
Zinc oxide also has low toxicity and adverse effects on the environment, and is also superior to other metals or compounds thereof in this respect.
It is already known that the combined use of a photocatalytic material and an amphoteric metal oxide promotes NOx decomposition, and this may also contribute to the NOx decomposition effect according to the present invention. However, the use of zinc oxide containing another element as a solid solution further enhances the NOx decomposition effect. This effect was first revealed this time.
The zinc oxide used as a raw material of the coating solution for forming a photocatalyst of the present invention may be a powder without any problem as long as it can be uniformly dispersed in the coating solution for forming a photocatalyst layer at least during coating. A dispersion liquid dispersed in a dispersion medium may be used. In the case of a dispersion, the pH of the coating solution for forming a photocatalyst layer needs to be 7.5 to 11, so that the dispersion is preferably neutral or alkaline, and preferably has a pH of 7 to 11. Particularly preferred.
The particle size of zinc oxide is not particularly limited, but the average particle size is preferably from 5 to 100 nm, particularly preferably from 10 to 50 nm.
（他元素）
　本発明の光触媒形成用塗布液の原料として用いる酸化亜鉛に含有される他元素とは、亜鉛及び酸素以外の元素であり、必ずしも限定されないが、陽性元素、特に４価以下の陽性元素であることが好ましく、１族元素、２族元素、遷移金属（３族～１１族）元素、１３族元素、１４族元素等が挙げられる。その具体例としては、水素、リチウム、ナトリウム、カリウム、ベリリウム、マグネシウム、カルシウム、スカンジウム、イットリウム、ランタン、チタン、ジルコニウム、ハフニウム、バナジウム、ニオブ、タンタル、クロム、モリブデン、タングステン、マンガン、鉄、コバルト、ニッケル、パラジウム、銅、銀、ホウ素、アルミニウム、ガリウム、インジウム、ケイ素、ゲルマニウム、錫、等が挙げられる。
　以上のうち、３価元素又は１３族元素であることがさらに好ましい。
　３価元素は、酸化亜鉛に固溶含有された状態で、３価の酸化状態として存在する元素であり、１３族元素のほか、鉄等が例示される。
　１３族元素としては、ホウ素、アルミニウム、ガリウム、インジウム等が例示される。
　以上の元素の内、アルミニウム又はガリウムが特に好ましい。これらの元素が固溶している酸化亜鉛としては、一般に導電性酸化亜鉛として販売されているものを使用してもよい。 (Other elements)
The other element contained in zinc oxide used as a raw material of the photocatalyst-forming coating liquid of the present invention is an element other than zinc and oxygen, and is not necessarily limited, but is a positive element, particularly a positive element having a valence of 4 or less. Preferred are Group 1 element, Group 2 element, transition metal (Group 3 to Group 11) element, Group 13 element, Group 14 element and the like. Specific examples thereof include hydrogen, lithium, sodium, potassium, beryllium, magnesium, calcium, scandium, yttrium, lanthanum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, Examples include nickel, palladium, copper, silver, boron, aluminum, gallium, indium, silicon, germanium, tin, and the like.
Among them, a trivalent element or a group 13 element is more preferable.
The trivalent element is an element that exists as a trivalent oxidation state in a state of being contained in a solid solution in zinc oxide, and includes, for example, iron and the like in addition to the group 13 element.
Examples of group 13 elements include boron, aluminum, gallium, indium and the like.
Of the above elements, aluminum or gallium is particularly preferred. As the zinc oxide in which these elements are dissolved, those generally sold as conductive zinc oxide may be used.
（光触媒粒子）
　本発明の光触媒層形成用塗布液は、成分（Ｂ）として、成分（Ａ）以外の光触媒粒子を必須成分として含有する。
　光触媒粒子は、光触媒材料を、光触媒層形成用塗布液に分散し得る程度の粒子径としたものである。
　本発明に用いられる光触媒材料は、成分（Ａ）以外の成分、好ましくは酸化亜鉛以外の成分からなり、光触媒活性を有する金属酸化物等を含む無機材料である。
　光触媒材料の主成分として具体的には、酸化チタン、チタン酸ストロンチウム、酸化錫、酸化ジルコニウム、酸化タングステン、酸化クロム、酸化モリブデン、酸化鉄、酸化ニッケル、酸化ルテニウム、酸化バナジウム、酸化ニオブ、酸化タンタル、酸化ロジウム、酸化レニウム等が挙げられる。これらの中でも、酸化チタン、チタン酸ストロンチウム、酸化タングステン等が好ましく、特にアナターゼ型又はルチル型の酸化チタンが好ましい。
　また、これらに、Ｐｔ、Ｒｈ、Ｒｕ、Ｎｂ、Ｃｕ、Ｓｎ、Ｎｉ、Ｆｅ、Ａｇ等の金属若しくはこれらの酸化物を添加したもの、また窒素、硫黄等の元素を微量成分として添加したものも、本発明の効果に悪影響を与えない限り用いることができる。これらにより、藻類等の微生物の防除をさらに増強する効果や、光触媒作用に紫外光のみならず可視光を利用する効果を期待し得る。
　光触媒材料微粒子の粒子径は特に限定されないが、平均粒子径が、５～１００ｎｍであることが好ましく、１０～５０ｎｍであることが特に好ましい。 (Photocatalyst particles)
The coating solution for forming a photocatalyst layer of the present invention contains, as an essential component, photocatalyst particles other than the component (A) as the component (B).
The photocatalyst particles have such a particle size that the photocatalyst material can be dispersed in the photocatalyst layer forming coating solution.
The photocatalyst material used in the present invention is an inorganic material comprising a component other than the component (A), preferably a component other than zinc oxide, and containing a metal oxide having photocatalytic activity.
Specific examples of the main components of the photocatalytic material include titanium oxide, strontium titanate, tin oxide, zirconium oxide, tungsten oxide, chromium oxide, molybdenum oxide, iron oxide, nickel oxide, ruthenium oxide, vanadium oxide, niobium oxide, and tantalum oxide. , Rhodium oxide, rhenium oxide and the like. Among these, titanium oxide, strontium titanate, tungsten oxide and the like are preferable, and anatase type or rutile type titanium oxide is particularly preferable.
In addition, those to which metals such as Pt, Rh, Ru, Nb, Cu, Sn, Ni, Fe, and Ag or oxides thereof are added, and those to which elements such as nitrogen and sulfur are added as trace components are also included. It can be used as long as the effects of the present invention are not adversely affected. Thus, an effect of further enhancing the control of microorganisms such as algae and an effect of utilizing not only ultraviolet light but also visible light for photocatalysis can be expected.
The particle size of the photocatalyst material fine particles is not particularly limited, but the average particle size is preferably 5 to 100 nm, and particularly preferably 10 to 50 nm.
　本発明の光触媒形成用塗布液の原料としての光触媒粒子には、粉体を用いてもよいが、予め光触媒粒子を分散媒に分散させてなる光触媒分散液を用いることが好ましい。
　光触媒分散液としては、一般に、その表面電位の効果で安定に分散させるために、酸性またはアルカリ性で水性分散媒に分散させたものが用いられている。
　本発明の光触媒層形成用塗布液には、酸性ないし中性の光触媒分散液を用いてもよいが、この場合は最終的にｐＨ７．５～１１に調整する工程が必要となり、該工程で分散性に支障を来すおそれもある。一方、ｐＨ８～１１の光触媒分散液を使用すれば、このｐＨ調整工程が不要であるため好ましい。
　成分（Ｂ）である光触媒の含有量は、光触媒層全体に対して、酸化物に換算して５質量％～６０質量％となるようにすることが好ましい。５質量％未満になると光触媒層の光触媒活性が著しく低下する。一方、６０質量％を越える場合には光触媒活性は高くなるものの、光触媒層と基材若しくは接着層との接着性が乏しくなる。
　成分（Ａ）も光触媒活性を有する場合があるが、その光触媒活性は比較的低く、成分（Ａ）による基材若しくは接着層との接着性に対する悪影響は少ない。従って、成分（Ａ）と成分（Ｂ）（酸化物換算）との合計含有量は、前記成分（Ｂ）のみの含有量上限より高くてもよく、光触媒層全体に対して１０質量％～９０質量％であることが好ましく、２０質量％～６０質量％であることがより好ましい。 Powder may be used for the photocatalyst particles as a raw material of the coating solution for photocatalyst formation of the present invention, but it is preferable to use a photocatalyst dispersion liquid in which the photocatalyst particles are dispersed in a dispersion medium in advance.
As the photocatalyst dispersion liquid, in general, an aqueous dispersion medium which is acidic or alkaline and is dispersed in an aqueous dispersion medium is used in order to stably disperse the dispersion under the effect of the surface potential.
An acidic or neutral photocatalyst dispersion may be used for the coating solution for forming a photocatalyst layer of the present invention, but in this case, a step of finally adjusting the pH to 7.5 to 11 is required. There is a risk that the sex may be affected. On the other hand, it is preferable to use a photocatalyst dispersion having a pH of 8 to 11, since this pH adjustment step is unnecessary.
It is preferable that the content of the photocatalyst as the component (B) is 5% by mass to 60% by mass in terms of oxide based on the entire photocatalyst layer. When the content is less than 5% by mass, the photocatalytic activity of the photocatalyst layer is significantly reduced. On the other hand, when the content exceeds 60% by mass, the photocatalytic activity becomes high, but the adhesion between the photocatalyst layer and the substrate or the adhesive layer becomes poor.
Component (A) may also have photocatalytic activity, but its photocatalytic activity is relatively low, and the adverse effect of component (A) on adhesion to a substrate or an adhesive layer is small. Therefore, the total content of the component (A) and the component (B) (in terms of oxide) may be higher than the upper limit of the content of the component (B) alone, and may be 10% by mass to 90% by mass with respect to the entire photocatalyst layer. % By mass, and more preferably from 20% by mass to 60% by mass.
（バインダー）
　本発明の光触媒層形成用塗布液は、さらに成分（Ｃ）として、（Ａ）及び（Ｂ）以外のバインダーを含有する。バインダーは、光触媒粉末を固着し、基材若しくは接着層と強固に接着させることを目的とする。
　本発明で用いるバインダーは、光触媒及び酸化亜鉛を除く金属酸化物又は金属水酸化物の１種以上を含有することが好ましく、これは光触媒及び酸化亜鉛を除く金属酸化物又は金属水酸化物の分散液に由来することがより好ましい。
　金属酸化物又は金属水酸化物の分散液は、光触媒層形成用塗布液を塗布した光触媒層を乾燥したときに、光触媒層中で金属酸化物ゲルもしくは水酸化物ゲルとなり、光触媒粉末を固着し、基材若しくは接着層と強固に接着させる効果を有している。金属成分としては、珪素、アルミニウム、チタニウム、ジルコニウム、マグネシウム、ニオブ、タンタル、タングステン、錫等の金属の酸化物ゲルもしくは水酸化物ゲル（但し光触媒であるものを除く。）を例示することができる。このうち、シリカ分散液又はアルミナ分散液が好ましく、特にシリカ分散液が好ましい。
　金属酸化物又は金属水酸化物の分散液は、分散液としての安定性を確保するために、解膠剤として酸又はアルカリを含有してもよい。但し、光触媒層形成用塗布液のｐＨが７．５～１１となる必要があるため、金属酸化物又は金属水酸化物の分散液は中性ないしアルカリ性であることが好ましく、ｐＨ７～１１であることが特に好ましい。 (binder)
The coating solution for forming a photocatalyst layer of the present invention further contains a binder other than (A) and (B) as component (C). The purpose of the binder is to fix the photocatalyst powder and firmly adhere to the substrate or the adhesive layer.
The binder used in the present invention preferably contains one or more of a metal oxide or a metal hydroxide other than the photocatalyst and zinc oxide. More preferably, it is derived from a liquid.
The dispersion of the metal oxide or the metal hydroxide becomes a metal oxide gel or a hydroxide gel in the photocatalyst layer when the photocatalyst layer coated with the photocatalyst layer forming coating solution is dried, and the photocatalyst powder is fixed. Has the effect of firmly adhering to the substrate or the adhesive layer. Examples of the metal component include oxide gels or hydroxide gels of metals such as silicon, aluminum, titanium, zirconium, magnesium, niobium, tantalum, tungsten, and tin (excluding those that are photocatalysts). . Among these, a silica dispersion or an alumina dispersion is preferred, and a silica dispersion is particularly preferred.
The dispersion of the metal oxide or the metal hydroxide may contain an acid or an alkali as a deflocculant in order to ensure the stability of the dispersion. However, since the pH of the coating solution for forming the photocatalyst layer needs to be 7.5 to 11, the dispersion of the metal oxide or metal hydroxide is preferably neutral or alkaline, and has a pH of 7 to 11. Is particularly preferred.
　本発明の光触媒層形成用塗布液に関しては、光触媒及び酸化亜鉛を除く金属酸化物又は金属水酸化物の分散液に加えて、光触媒層の強度を改善するバインダー等の目的でもし必要であれば、樹脂、加水分解性シラン化合物又はその部分加水分解縮合物、若しくは金属酸化物又は金属水酸化物の前駆体を含有してもよい。
　樹脂としては、光触媒作用による劣化を受け難い、シリコーン樹脂、シリコーン変性樹脂、フッ素樹脂等が挙げられる。シリコーン変性樹脂としては、アクリルシリコーン樹脂、エポキシシリコーン樹脂等が挙げられる。
　加水分解性シラン化合物は、一般構造式ＲｎＳｉＸ（４－ｎ）（ここで、Ｒは水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアルケニル基、又は置換基を有してもよいアリール基を表し、Ｘは塩素原子、置換基を有してもよいアルコキシ基、置換基を有してもよいアルケニルオキシ基、又は置換基を有してもよいアリールオキシ基を表し、ｎは０～３のいずれかの整数を表す。）で表される。加水分解性シラン化合物の部分加水分解縮合物とは、前記の加水分解性シラン化合物の１種または２種以上を加水分解し縮合して得られる化合物である。これらは本発明の光触媒層形成用塗布液に用いられる光触媒分散液に含有されるアルカリ分を触媒として加水分解され、あるいは塗布後の加熱により加水分解が促進され得る。
　金属酸化物又は金属水酸化物の前駆体は、加水分解することにより、金属酸化物又は金属水酸化物に変化する物質を意味し、具体的には、前記金属を含有するアルコキシド、前記金属を含有するキレート化合物等、より具体的には、シランアルコキシド、アルミニウムアルコキシド、アルミニウムキレート化合物、チタンアルコキシド、チタンキレート化合物、ジルコニウムアルコキシド、ジルコニウムキレート化合物等が例示される。これらは本発明の光触媒層形成用塗布液に用いられる光触媒分散液に含有されるアルカリ分を触媒として加水分解され、あるいは塗布後の加熱により加水分解が促進され得る。 Regarding the coating solution for forming a photocatalyst layer of the present invention, in addition to the dispersion of the metal oxide or metal hydroxide except for the photocatalyst and zinc oxide, if necessary for the purpose of a binder or the like for improving the strength of the photocatalyst layer, if necessary , A resin, a hydrolyzable silane compound or a partial hydrolysis condensate thereof, or a metal oxide or a metal hydroxide precursor.
Examples of the resin include a silicone resin, a silicone-modified resin, and a fluororesin that are not easily deteriorated by a photocatalytic action. Examples of the silicone-modified resin include an acrylic silicone resin and an epoxy silicone resin.
The hydrolyzable silane compound has the general structural formula R n SiX (4-n) (where R is a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or X represents an optionally substituted aryl group, and X represents a chlorine atom, an optionally substituted alkoxy group, an optionally substituted alkenyloxy group, or an optionally substituted substituent. Represents an aryloxy group, and n represents an integer of any of 0 to 3.) The partially hydrolyzed condensate of a hydrolyzable silane compound is a compound obtained by hydrolyzing and condensing one or more of the above hydrolyzable silane compounds. These are hydrolyzed by using an alkali component contained in the photocatalyst dispersion used in the photocatalyst layer forming coating solution of the present invention as a catalyst, or the hydrolysis can be promoted by heating after coating.
A precursor of a metal oxide or a metal hydroxide means a substance that is converted to a metal oxide or a metal hydroxide by hydrolysis, and specifically, an alkoxide containing the metal, Examples of the chelate compound and the like contained therein, more specifically, silane alkoxide, aluminum alkoxide, aluminum chelate compound, titanium alkoxide, titanium chelate compound, zirconium alkoxide, zirconium chelate compound, and the like. These are hydrolyzed by using an alkali component contained in the photocatalyst dispersion used in the photocatalyst layer forming coating solution of the present invention as a catalyst, or the hydrolysis can be promoted by heating after coating.
（分散媒）
　本発明の光触媒層形成用塗布液は、水性分散媒を含有している。
　分散媒は、水、又は水とそれに混合可能な有機溶媒とを含む溶液からなる水性分散媒であることが好ましい。分散媒としては、光触媒分散液や、バインダーとしての金属酸化物又は金属水酸化物の分散液に予め含まれていた分散媒をそのまま使用してよく、また固形分濃度を調整しあるいは下記のように分散媒の組成を調整するために、水及び／又は有機溶媒を追加してもよい。
　特に、塗工時の濡れ性に優れ、塗工後の乾燥が容易である点から、水と揮発性の有機溶媒とを含む溶液からなる水性分散媒が好ましい。有機溶媒としては、メタノール、エタノール、ｎ－プロパノール、イソプロパノール、ｎ－ブタノール等の低級アルコールが好ましい。また有機溶媒の濃度は、１０～８０質量％が好ましく、３０～６０質量％がより好ましい。以上により、塗工時のハジキ、接着層の削れ等の不都合が生じず、均一な光触媒層を形成することができる。 (Dispersion medium)
The photocatalyst layer-forming coating liquid of the present invention contains an aqueous dispersion medium.
The dispersion medium is preferably an aqueous dispersion medium composed of water or a solution containing water and an organic solvent miscible with water. As the dispersion medium, a photocatalyst dispersion liquid, a dispersion medium previously contained in a dispersion liquid of a metal oxide or a metal hydroxide as a binder may be used as it is, or the solid content concentration may be adjusted or as described below. In order to adjust the composition of the dispersion medium, water and / or an organic solvent may be added.
In particular, an aqueous dispersion medium composed of a solution containing water and a volatile organic solvent is preferable because it has excellent wettability during coating and is easy to dry after coating. As the organic solvent, lower alcohols such as methanol, ethanol, n-propanol, isopropanol and n-butanol are preferable. The concentration of the organic solvent is preferably from 10 to 80% by mass, more preferably from 30 to 60% by mass. As described above, a uniform photocatalyst layer can be formed without inconveniences such as repelling at the time of coating and scraping of the adhesive layer.
（他の成分）
　本発明の光触媒層形成用塗布液には、本発明の効果を減弱させない範囲で、上記各成分の他に、ｐＨ調整剤、分散剤、界面活性剤、増粘剤、色素等が含有されていてもよい。 (Other ingredients)
The coating solution for forming a photocatalyst layer of the present invention contains a pH adjuster, a dispersant, a surfactant, a thickener, a dye, and the like, in addition to the components described above, as long as the effects of the present invention are not reduced. You may.
（光触媒層形成用塗布液の製造）
　本発明の光触媒層形成用塗布液の製造は、基本的に、以上の各原料を混合し均一にすればよく、混合の順序は特に限定されない。ただし、混合によりｐＨや有機溶媒濃度が大きく変動する場合には、その影響で粒子の凝集やゲル化が起きるのを防ぐため、このような変動を回避し得る順序を採用し、あるいは一方の原料を他方の原料に滴下する等により徐々に混合する方法を採用するのが好ましい。 (Production of coating solution for forming photocatalyst layer)
The production of the coating solution for forming a photocatalyst layer according to the present invention may basically be performed by mixing the above-mentioned raw materials to make them uniform, and the mixing order is not particularly limited. However, when the pH or the concentration of the organic solvent fluctuates greatly due to the mixing, in order to prevent aggregation and gelation of particles due to the influence, an order that can avoid such fluctuations is adopted. It is preferable to employ a method of gradually mixing the mixture by dripping into the other material.
（光触媒担持構造体）
　本発明の光触媒担持構造体は、基材と、該基材の表面の少なくとも一部に被着された光触媒層とを含む構造体であって、光触媒層は、本発明の光触媒層形成用塗布液の乾燥固化物であることを特徴とする。
　基材としては、特に限定されないが、金属、セラミックス、陶磁器、石、セメント、コンクリート、ガラス、プラスチック、木、合成樹脂、合成繊維、天然繊維、テント地またはそれらを組み合わせてなる複合材料を例示することができる。
　基材の形状としては、フィルム状、シート状、板状、管状、繊維状、網状等どのような複雑な形状のものも使用可能である。基材の厚さとしては１０μｍ以上のものであれば強固に担持することができるので好ましい。 (Photocatalyst carrying structure)
The photocatalyst-supporting structure of the present invention is a structure including a base material and a photocatalyst layer adhered to at least a part of the surface of the base material, and the photocatalyst layer is a coating for forming a photocatalyst layer of the present invention. It is characterized by being a dried solidified liquid.
The substrate is not particularly limited, and examples thereof include metals, ceramics, ceramics, stones, cement, concrete, glass, plastic, wood, synthetic resins, synthetic fibers, natural fibers, tents, and composite materials obtained by combining them. be able to.
As the shape of the substrate, any complicated shape such as a film, a sheet, a plate, a tube, a fiber, and a net can be used. The thickness of the substrate is preferably 10 μm or more because it can be firmly supported.
（光触媒層）
　本発明の光触媒担持構造体における光触媒層は、本発明の光触媒層形成用塗布液を、基材の表面の少なくとも一部に塗布し、これを乾燥させて固化させることにより、製造することができる。
　塗布の方法としては、スプレーコート、スピンコート、バーコート、ローラーコート、刷毛塗り、スクリーン印刷、グラビアコート等を用いることができ、また基材の全面に塗布する場合にはディップ法（浸漬法）を用いてもよい。
　前記の乾燥及び固化の工程は、常温で実施してもよいが、乾燥及び固化を促進するために加熱してもよく、スプレーコート等の方法を用いて均一に塗布できるのであれば、塗布前に基材を予熱してもよい。
　この加熱における条件は、必ずしも限定されるものではないが、基材の変形又は劣化が生じない温度及び時間の範囲で行うことが好ましい。特に温度を２００℃以下とすることが好ましく、これは基材が非耐熱性合成樹脂を含む場合に特に適している。本発明において非耐熱性合成樹脂とは、１６０℃で変形する合成樹脂であり、塩化ビニル樹脂、アクリル樹脂、スチレン樹脂、オレフィン樹脂、またこれらからなる複合樹脂等が挙げられる。温度をこのような変形温度より高温とすることも可能であるが、その場合には基材の変形が生じない温度及び時間の範囲に留めることが好ましい。
　光触媒層の厚みは、特に制限されないが、厚い方が光触媒活性が高い。しかし厚みが５μｍを超えると活性はほとんど変わらない。また厚みが０．１μｍを下回ると、透光性は良くなるものの、光触媒が利用する紫外線をも透過してしまうために、高い活性は望めなくなる。このため、通常は０．１～５μｍの範囲が好ましく、０．５～５μｍの範囲がより好ましい。 (Photocatalyst layer)
The photocatalyst layer in the photocatalyst supporting structure of the present invention can be manufactured by applying the coating solution for forming a photocatalyst layer of the present invention to at least a part of the surface of a substrate, and drying and solidifying this. .
Spray coating, spin coating, bar coating, roller coating, brush coating, screen printing, gravure coating, and the like can be used as a coating method, and a dip method (dipping method) when coating the entire surface of the substrate. May be used.
The drying and solidification steps may be performed at room temperature, but may be heated to promote drying and solidification. The substrate may be preheated.
The conditions for this heating are not necessarily limited, but it is preferable to perform the heating within a temperature and time range in which deformation or deterioration of the substrate does not occur. In particular, the temperature is preferably set to 200 ° C. or lower, which is particularly suitable when the substrate contains a non-heat-resistant synthetic resin. In the present invention, the non-heat-resistant synthetic resin is a synthetic resin that deforms at 160 ° C., and includes a vinyl chloride resin, an acrylic resin, a styrene resin, an olefin resin, and a composite resin composed of these. The temperature may be higher than such a deformation temperature, but in such a case, it is preferable to keep the temperature and time within a range in which the deformation of the substrate does not occur.
The thickness of the photocatalyst layer is not particularly limited, but the thicker the photocatalytic activity. However, when the thickness exceeds 5 μm, the activity hardly changes. When the thickness is less than 0.1 μm, although the translucency is improved, high activity cannot be expected because ultraviolet light used by the photocatalyst is transmitted. For this reason, the range is usually preferably from 0.1 to 5 μm, more preferably from 0.5 to 5 μm.
（接着層）
　基材と光触媒層との間には、１種又は複数の接着層（中間層）をさらに設けてもよい。これにより、例えば基材に含有される成分が表面に拡散することで光触媒活性を阻害することを防止することができる。また逆に、光触媒の作用により基材が劣化することを防止することができる。特に、基材と光触媒層との接着を促進し、併せて以上の効果を得るために、１種又は複数の接着層を設けることが好ましい。
　接着層の材質としては、基材を光触媒作用による劣化から保護し、さらに光触媒層を強固に固定できるものであれば特に制限されないが、具体的には（１）シリコーン含有量が酸化物に換算して２～６０質量％である、アクリルシリコーン樹脂、エポキシシリコーン樹脂、ポリエステルシリコーン樹脂等のシリコーン変性樹脂、（２）ポリシロキサンを酸化物に換算して３～９０質量％含有する樹脂、（３）コロイダルシリカを酸化物に換算して５～９０質量％含有する樹脂、等を使用することができる。これらの樹脂は光触媒を強固に接着し、基材を光触媒から保護するのに適当であり、また基材に可塑剤等の成分が含まれる場合にこれが表面へ拡散するのを防ぐことができる。
　シリコーン含有量が酸化物に換算して２質量％未満のアクリルシリコーン樹脂等のシリコーン変性樹脂やポリシロキサン含有量が酸化物に換算して３質量％未満の樹脂、コロイダルシリカ含有量が酸化物に換算して５質量％未満の樹脂では、光触媒層との接着が悪くなり、また、接着層が光触媒により劣化し、光触媒層が剥離し易くなる。シリコーン含有量が酸化物に換算して１０質量％を超えるアクリルシリコーン樹脂等のシリコーン変性樹脂やポリシロキサン含有量が酸化物に換算して９０質量％を超える樹脂、コロイダルシリカ含有量が酸化物に換算して９０質量％を超える樹脂では、基材との密着性が低下する。
　またシリコーンを導入する樹脂としては、アクリル樹脂、エポキシ樹脂、ポリエステル樹脂、アルキド樹脂、ウレタン樹脂等を例示することができる。これらの内、アクリル樹脂、エポキシ樹脂、ポリエステル樹脂が、成膜性、強靭性、担体との密着性の点で特に好ましい。これらの樹脂は、溶液状であってもエマルジョンタイプであってもどちらでも使用できる。また、架橋剤等の添加物が含まれていてもよい。
　前記接着層の樹脂に含まれるポリシロキサンが炭素数１～５のアルコキシ基を有するシランアルコキシドの加水分解物あるいは該加水分解物生成物である場合には、接着性及び耐久性がより向上した担持構造体を得ることができる。シランアルコキシドのアルコキシ基の炭素数が６を超えると、加水分解速度が非常に遅いので、樹脂中で硬化させるのが困難になり、接着性や耐久性が悪くなる。また、部分的に塩素を含んだシランアルコキシドを加水分解したポリシロキサンを使用することもできるが、塩素を多量に含有したポリシロキサンを使用する場合には、不純物の塩素イオンにより、基材が腐食されたり、接着性が低下するおそれがある。
　接着層は、以上の成分若しくはその前駆体を含有する接着層塗布液を基材表面に塗布し、乾燥し固化させることで得られる。この方法は、接着層塗布液の組成に応じて選択すればよいが、光触媒層のそれと同様に行うことができる。
　接着層の厚みは、特に制限されないが、通常は０．１～１０μｍの範囲が好ましく、０．５～５μｍの範囲がより好ましい。
　さらに、基材と接着層との密着性を良くするために、表面に放電処理やプライマー処理等の易接着処理を施した基材を用いてもよい。 (Adhesive layer)
One or more adhesive layers (intermediate layers) may be further provided between the substrate and the photocatalyst layer. Thereby, it is possible to prevent, for example, the components contained in the base material from diffusing to the surface and inhibiting the photocatalytic activity. Conversely, it is possible to prevent the substrate from being deteriorated by the action of the photocatalyst. In particular, it is preferable to provide one or a plurality of adhesive layers in order to promote the adhesion between the substrate and the photocatalyst layer and obtain the above-mentioned effects.
The material of the adhesive layer is not particularly limited as long as it can protect the base material from deterioration due to the photocatalytic action and can firmly fix the photocatalytic layer. Specifically, (1) the silicone content is converted to oxide. A silicone-modified resin such as an acrylic silicone resin, an epoxy silicone resin, or a polyester silicone resin, which is 2 to 60% by mass; (2) a resin containing 3 to 90% by mass of a polysiloxane in terms of oxide; ) A resin containing 5 to 90% by mass of colloidal silica in terms of oxide can be used. These resins firmly adhere to the photocatalyst, are suitable for protecting the substrate from the photocatalyst, and can prevent the diffusion of the plasticizer and other components to the surface when the substrate contains a component such as a plasticizer.
Silicone-modified resins such as acrylic silicone resin having a silicone content of less than 2% by mass in terms of oxides, resins having a polysiloxane content of less than 3% by mass in terms of oxides, and colloidal silica contents having an oxide content When the amount of the resin is less than 5% by mass, adhesion to the photocatalyst layer is deteriorated, and the adhesion layer is deteriorated by the photocatalyst, and the photocatalyst layer is easily peeled. Silicone-modified resins such as acrylic silicone resin whose silicone content exceeds 10% by mass in terms of oxides, resins whose polysiloxane content exceeds 90% by mass in terms of oxides, and colloidal silica content in which oxides exist If the resin exceeds 90% by mass, the adhesion to the substrate is reduced.
Examples of the resin into which silicone is introduced include an acrylic resin, an epoxy resin, a polyester resin, an alkyd resin, and a urethane resin. Among them, acrylic resin, epoxy resin and polyester resin are particularly preferable in view of film formability, toughness, and adhesion to a carrier. These resins can be used in either a solution state or an emulsion type. Further, additives such as a crosslinking agent may be contained.
When the polysiloxane contained in the resin of the adhesive layer is a hydrolyzate of a silane alkoxide having an alkoxy group having 1 to 5 carbon atoms or a product of the hydrolyzate, a carrier having improved adhesion and durability is provided. A structure can be obtained. When the number of carbon atoms of the alkoxy group of the silane alkoxide exceeds 6, the hydrolysis rate is extremely slow, so that it is difficult to cure the resin in a resin, and the adhesiveness and durability deteriorate. In addition, a polysiloxane obtained by hydrolyzing a silane alkoxide partially containing chlorine can be used.However, when a polysiloxane containing a large amount of chlorine is used, the base material is corroded by chlorine ions as impurities. Or the adhesiveness may be reduced.
The adhesive layer is obtained by applying an adhesive layer coating solution containing the above components or a precursor thereof to the surface of the substrate, drying and solidifying. This method may be selected according to the composition of the adhesive layer coating solution, but can be performed in the same manner as that of the photocatalyst layer.
The thickness of the adhesive layer is not particularly limited, but is usually preferably in the range of 0.1 to 10 μm, more preferably in the range of 0.5 to 5 μm.
Further, in order to improve the adhesion between the base material and the adhesive layer, a base material whose surface has been subjected to an easy adhesion treatment such as a discharge treatment or a primer treatment may be used.
（使用環境）
　本発明の光触媒担持構造体を使用する環境は、光照射を受ける限り特に限定されないが、紫外光を含む外光の照射を受け（直射日光を受けない日陰であってもよい。）、かつ藻類が発生し得る屋外環境での使用が好ましい。水中での使用も可能ではあるが、常時水と接触している環境では亜鉛が溶出し減少しやすいので、常時水と接触している環境を除く環境で使用することが好ましく、降水、散水、結露等により一時的に水と接触して構造体表面の汚れが洗い流される環境で使用することが特に好ましい。特に樹脂系サイディング、窯業系サイディング、タイル等の建築物の外装材、またフッ素塗料やアクリルシリコーン塗料等の現場塗工により施工された外壁、屋外に設置するウッドデッキ（木材又は木材プラスチック複合材からなるもの）や、テント等に適している。
　また窒素酸化物の多い道路沿いの環境で使用することも好ましく、特に看板や道路標識等に使用すれば表面の汚れを防止する効果もあり好ましい。 (usage environment)
The environment in which the photocatalyst-supporting structure of the present invention is used is not particularly limited as long as it is irradiated with light, but is irradiated with external light including ultraviolet light (the shade may be protected from direct sunlight) and algae. It is preferable to use in an outdoor environment where the occurrence of odor can occur. Although it can be used in water, zinc elutes and tends to decrease in environments that are in constant contact with water, so it is preferable to use it in environments other than those that are in constant contact with water, such as precipitation, watering, It is particularly preferable to use it in an environment where the surface of the structure is temporarily washed off by temporary contact with water due to dew condensation or the like. In particular, exterior materials for buildings such as resin-based siding, ceramic-based siding, and tiles, outer walls constructed by in-situ coating with fluorine paint, acrylic silicone paint, etc., and wooden decks installed outdoors (made of wood or wood-plastic composite ) And tents.
It is also preferable to use it in an environment along a road with a large amount of nitrogen oxides, and it is particularly preferable to use it in a signboard or a road sign because it has the effect of preventing surface contamination.
　次に、本発明の実施例によってさらに詳細に説明するが、本発明はこれにより限定されるものではない。 Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.
　基材としては白色テント地を用いた。
　アクリルシリコーン樹脂を、エタノール－ブタノール－酢酸エチル混合溶媒で固形分濃度２０質量％となるように希釈し、接着層形成用塗布液を得た。
　接着層形成用塗布液を基材の片側表面にバーコート成膜により１回塗布し、１００℃で５分乾燥させ、厚さ約１．０μｍの接着層を形成させた。 A white tent was used as a substrate.
The acrylic silicone resin was diluted with a mixed solvent of ethanol-butanol-ethyl acetate to a solid content concentration of 20% by mass to obtain a coating solution for forming an adhesive layer.
The coating liquid for forming an adhesive layer was applied once to one surface of the substrate by bar coating and dried at 100 ° C. for 5 minutes to form an adhesive layer having a thickness of about 1.0 μm.
（光触媒層形成用塗布液及び光触媒担持構造体の作製）
　以下の各実施例及び比較例の光触媒層形成用塗布液を、上記接着層の上にバーコート成膜により１回塗布し、１００℃で５分乾燥させ、厚さ約０．５μｍの光触媒層を形成させることにより、光触媒担持構造体を得た。 (Preparation of photocatalyst layer forming coating liquid and photocatalyst supporting structure)
The coating solution for forming a photocatalyst layer of each of the following Examples and Comparative Examples was applied once by bar coating on the above-mentioned adhesive layer, and dried at 100 ° C. for 5 minutes to form a photocatalyst layer having a thickness of about 0.5 μm. Was formed to obtain a photocatalyst-carrying structure.
（実施例１）
　シリカを水酸化ナトリウムに懸濁させビーズミルで粉砕し、粒子径４～６ｎｍ、固形分濃度２０質量％、ｐＨ９のアルカリ性シリカゾルを得た。
　１３質量％の炭酸水素アンモニウム水溶液５７５ｇを、試薬酸化亜鉛の水分散液（平均粒径１．０μｍ、５質量％）２９５０ｇに加えて室温で撹拌した後、７０℃まで加温し、さらに３０分間熟成することにより、塩基性炭酸亜鉛の水分散液を得た。次いで、２．８質量％の硫酸アルミニウム水溶液５１４．３ｇを、上記で得た塩基性炭酸亜鉛の水分散液に加えて室温で撹拌した後、７０℃まで加温し、さらに３０分間熟成した。この分散液から固形物を濾別し、乾燥した後、３００℃で３時間焼成し、更に水素雰囲気下に４００℃で２時間還元焼成した。この焼成物を解砕して、一次粒径約２０ｎｍのアルミニウムドープ酸化亜鉛粉末を得た。
　上記シリカゾル９．４ｇに、撹拌しながらイオン交換水８．０ｇ、アルカリ性二酸化チタンゾル（石原産業社製ＳＴＳ－２１、アナターゼ型、一次粒子径２０ｎｍ、固形分濃度４０質量％、ｐＨ８．５）５．０ｇを順次混合し、続いてアルコール系溶媒２７．１ｇを徐々に滴下して混合し、その後界面活性剤溶液０．５ｇを添加した。
　これに上記アルミニウムドープ酸化亜鉛粉末０．４ｇを混合して分散させ、光触媒形成用塗布液を得た。 (Example 1)
The silica was suspended in sodium hydroxide and pulverized with a bead mill to obtain an alkaline silica sol having a particle diameter of 4 to 6 nm, a solid content of 20% by mass, and a pH of 9.
575 g of a 13% by mass aqueous solution of ammonium hydrogen carbonate was added to 2950 g of an aqueous dispersion of the reagent zinc oxide (average particle size: 1.0 μm, 5% by mass), stirred at room temperature, and then heated to 70 ° C. and further 30 minutes By aging, an aqueous dispersion of basic zinc carbonate was obtained. Next, 514.3 g of a 2.8 mass% aqueous aluminum sulfate solution was added to the aqueous dispersion of basic zinc carbonate obtained above, stirred at room temperature, heated to 70 ° C., and aged for 30 minutes. The solid was filtered from this dispersion, dried, fired at 300 ° C. for 3 hours, and further reduced and fired at 400 ° C. for 2 hours in a hydrogen atmosphere. This calcined product was crushed to obtain an aluminum-doped zinc oxide powder having a primary particle size of about 20 nm.
4. 9.4 g of the above silica sol, 8.0 g of ion-exchanged water while stirring, and an alkaline titanium dioxide sol (STS-21, anatase type, primary particle diameter 20 nm, primary particle diameter 20 nm, solid content concentration 40 mass%, pH 8.5, pH 8.5) by Ishihara Sangyo Co., Ltd. 0 g were sequentially mixed, and then 27.1 g of an alcohol-based solvent was gradually dropped and mixed, and then 0.5 g of a surfactant solution was added.
0.4 g of the above aluminum-doped zinc oxide powder was mixed and dispersed therein to obtain a coating solution for forming a photocatalyst.
（比較例１）
　アルミニウムドープ酸化亜鉛を用いなかった以外は実施例１と同様にして、光触媒形成用塗布液を得た。 (Comparative Example 1)
A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that the aluminum-doped zinc oxide was not used.
（比較例２）
　アルミニウムドープ酸化亜鉛に代えて、ニッケル粉末（一次粒径０．５～５０μｍ）を用いた以外は実施例１と同様にして、光触媒形成用塗布液を得た。 (Comparative Example 2)
A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that nickel powder (primary particle size: 0.5 to 50 μm) was used instead of aluminum-doped zinc oxide.
（比較例３）
　アルミニウムドープ酸化亜鉛に代えて、キュプロニッケル粉末（銅７０質量％とニッケル３０質量％からなる合金、一次粒径４０～５０μｍ）を用いた以外は実施例１と同様にして、光触媒形成用塗布液を得た。 (Comparative Example 3)
A coating solution for forming a photocatalyst in the same manner as in Example 1 except that cupronickel powder (an alloy composed of 70% by mass of copper and 30% by mass of nickel, primary particle size of 40 to 50 μm) was used instead of aluminum-doped zinc oxide. I got
（比較例４）
　アルミニウムドープ酸化亜鉛に代えて、試薬酸化亜鉛（平均粒径１．０μｍ）を用いた以外は実施例１と同様にして、光触媒形成用塗布液を得た。 (Comparative Example 4)
A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that a reagent zinc oxide (average particle size: 1.0 μm) was used instead of aluminum-doped zinc oxide.
（比較例５）
　アルカリ性二酸化チタンゾルに代えて、実施例１で用いたアルミニウムドープ酸化亜鉛粉末の水分散液（固形分濃度４０質量％、ｐＨ８．５）を用いた以外は比較例１と同様にして、光触媒形成用塗布液を得た。 (Comparative Example 5)
A photocatalyst for forming a photocatalyst was prepared in the same manner as in Comparative Example 1, except that the aqueous dispersion of the aluminum-doped zinc oxide powder used in Example 1 (solid content concentration: 40% by mass, pH 8.5) was used instead of the alkaline titanium dioxide sol. A coating solution was obtained.
（比較例６）
　アルカリ性二酸化チタンゾルに代えて、酸性二酸化チタンゾル（石原産業社製ＳＴＳ－０１、アナターゼ型、一次粒子径７ｎｍ、固形分濃度３０質量％、ｐＨ１．５）６．７ｇを用い、アルコール系溶媒使用量を２５．４ｇとした以外は実施例１と同様にして、光触媒形成用塗布液を得た。 (Comparative Example 6)
Instead of the alkaline titanium dioxide sol, 6.7 g of an acidic titanium dioxide sol (STS-01, anatase type, primary particle diameter 7 nm, solid content concentration 30 mass%, pH 1.5) manufactured by Ishihara Sangyo Co., Ltd. A coating solution for forming a photocatalyst was obtained in the same manner as in Example 1 except that the amount was changed to 25.4 g.
（防藻試験）
　上記の方法により得られた光触媒担持構造体（実施例１；比較例１～３、６）を、直射日光及び降雨を受ける屋外で曝露し、４ヶ月後及び６ヶ月後に評価した。評価は次の基準により行った。
×：藻の発生が甚だしく全体が緑色となり実用性なし。
△：わずかな汚れ又は藻の発生が見られる。
○：汚れ、藻の発生ともになし。
　結果は表１の通りであった。 (Algae prevention test)
The photocatalyst-carrying structure (Example 1; Comparative Examples 1 to 3, and 6) obtained by the above method was exposed outdoors under direct sunlight and rain, and evaluated after 4 months and 6 months. The evaluation was performed according to the following criteria.
X: Algae generation was extremely green and the whole was not practical.
Δ: Slight dirt or generation of algae is observed.
：: Neither dirt nor algae was generated.
The results were as shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　以上の結果から、光触媒材料として酸性二酸化チタンゾルを用いた場合は藻の発生が甚だしいが、それに比較して光触媒材料としてアルカリ性二酸化チタンゾルを用いた場合はやや防藻効果があること、さらに防藻成分としてアルミニウムドープ酸化亜鉛を光触媒層に併用すれば長期に亘り確実な防藻効果が得られることが明らかにされた。 From the above results, when acidic titanium dioxide sol was used as the photocatalytic material, the generation of algae was severe, but in comparison, when alkaline titanium dioxide sol was used as the photocatalytic material, there was a slight anti-algal effect. It has been clarified that if aluminum-doped zinc oxide is used in combination with the photocatalyst layer, a reliable anti-algal effect can be obtained over a long period of time.
（ＮＯｘ除去試験）
　上記の方法により得られた光触媒担持構造体（実施例１；比較例１、２、４、５）を用い、光照射によるＮＯｘ分解機能の評価を実施した。
　ＮＯｘ分解機能の評価は、「ＪＩＳ　Ｒ　１７０１－１：２０１０　ファインセラミックス－光触媒材料の空気浄化性能試験方法－第１部：窒素酸化物の除去性能」における「除去量が小さい試験片の試験方法」に従い、試験片１枚あたりのＮＯｘの除去量を測定した。
　結果は表２の通りであった。 (NOx removal test)
Using the photocatalyst-carrying structure (Example 1; Comparative Examples 1, 2, 4, and 5) obtained by the above method, evaluation of the NOx decomposition function by light irradiation was performed.
The evaluation of the NOx decomposition function is described in "JIS R 1701-1: 2010 Fine Ceramics-Test Method for Air Purification Performance of Photocatalyst Material-Part 1: Removal Performance of Nitrogen Oxide""Test Method for Specimen with Small Removal" , The amount of NOx removed per test piece was measured.
The results were as shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　以上の結果から、アルミニウムドープ酸化亜鉛自体には光触媒によるＮＯｘ分解効果はないこと、二酸化チタン光触媒に試薬酸化亜鉛を併用してもある程度のＮＯｘ分解効果が見られるものの、アルミニウムドープ酸化亜鉛を併用すればさらにＮＯｘ分解が促進されることが明らかにされた。 From the above results, aluminum-doped zinc oxide itself has no NOx decomposing effect by the photocatalyst. Although titanium dioxide photocatalyst has a certain NOx decomposing effect even when the reagent zinc oxide is used in combination, the use of aluminum-doped zinc oxide is not enough. It was further found that NOx decomposition was further promoted.

Claims (15)

  1. 成分（Ａ）：他元素が固溶している酸化亜鉛粒子と、
    成分（Ｂ）：（Ａ）以外の光触媒粒子と、
    成分（Ｃ）：（Ａ）及び（Ｂ）以外のバインダーと、
    成分（Ｄ）：水性分散媒と
    を含有し、ｐＨが７．５～１１である、光触媒層形成用塗布液。     Component (A): zinc oxide particles in which other elements are dissolved,
    Component (B): photocatalyst particles other than (A),
    Component (C): a binder other than (A) and (B),
    Component (D): a coating solution for forming a photocatalyst layer, which contains an aqueous dispersion medium and has a pH of 7.5 to 11.
  2. 成分（Ａ）における他元素が、４価以下の陽性元素である、請求項１に記載の光触媒層形成用塗布液。 The coating solution for forming a photocatalyst layer according to claim 1, wherein the other element in the component (A) is a positive element having a valence of 4 or less.
  3. 成分（Ａ）における他元素が、１３族元素である、請求項１に記載の光触媒層形成用塗布液。 The coating liquid for forming a photocatalyst layer according to claim 1, wherein the other element in the component (A) is a Group 13 element.
  4. 成分（Ｂ）が酸化チタン粒子である、請求項１～３のいずれかに記載の光触媒形成用塗布液。 The coating solution for forming a photocatalyst according to any one of claims 1 to 3, wherein the component (B) is a titanium oxide particle.
  5. 成分（Ｂ）が、光触媒層形成用塗布液の原料としての光触媒分散液に由来し、該分散液のｐＨが８～１１である、請求項１～４のいずれかに記載の光触媒層形成用塗布液。 The photocatalyst layer-forming solution according to any one of claims 1 to 4, wherein the component (B) is derived from a photocatalyst dispersion solution as a raw material of a photocatalyst layer-forming coating solution, and the dispersion solution has a pH of 8 to 11. Coating liquid.
  6. 成分（Ｃ）が、金属酸化物及び金属水酸化物から成る群から選択される少なくとも１種である、請求項１～５のいずれかに記載の光触媒層形成用塗布液。 The coating solution for forming a photocatalyst layer according to any one of claims 1 to 5, wherein the component (C) is at least one selected from the group consisting of a metal oxide and a metal hydroxide.
  7. 基材表面の少なくとも一部に、請求項１～６のいずれかに記載の光触媒層形成用塗布液を塗布し、乾燥する工程を含む、光触媒担持構造体の製造方法。 A method for producing a photocatalyst-supporting structure, comprising a step of applying the photocatalyst layer-forming coating liquid according to any one of claims 1 to 6 to at least a part of the surface of a substrate, and drying.
  8. 基材表面の光触媒層形成用塗布液を塗布する部分に、予め接着層が設けられている、請求項７に記載の光触媒担持構造体の製造方法。 The method for producing a photocatalyst-carrying structure according to claim 7, wherein an adhesive layer is provided in advance on a portion of the surface of the substrate to which the coating solution for forming a photocatalyst layer is applied.
  9. 前記乾燥工程における温度が２００℃以下である、請求項７又は８に記載の光触媒担持構造体の製造方法。 The method for producing a photocatalyst-supporting structure according to claim 7 or 8, wherein the temperature in the drying step is 200 ° C or less.
  10. 基材と、該基材の表面の少なくとも一部に被着された、請求項１～６のいずれかに記載の光触媒層形成用塗布液の乾燥固化物からなる光触媒層とを含む、光触媒担持構造体。 7. A photocatalyst carrier comprising: a substrate; and a photocatalyst layer formed of a dried and solidified product of the coating solution for forming a photocatalyst layer according to claim 1, which is applied to at least a part of the surface of the substrate. Structure.
  11. 前記基材と、前記光触媒層との間に、接着層を含む、請求項１０に記載の光触媒担持構造体。 The photocatalyst supporting structure according to claim 10, further comprising an adhesive layer between the substrate and the photocatalyst layer.
  12. 基材が非耐熱性合成樹脂を含む、請求項１０又は１１に記載の光触媒担持構造体。 The photocatalyst supporting structure according to claim 10, wherein the substrate includes a non-heat-resistant synthetic resin.
  13. テント地である、請求項１０～１２のいずれかに記載の光触媒担持構造体。 The photocatalyst supporting structure according to any one of claims 10 to 12, which is a tent ground.
  14. 請求項１０～１３のいずれかに記載の光触媒担持構造体により藻類の生育及び／又は繁殖を抑制する方法。 A method for suppressing the growth and / or reproduction of algae by the photocatalyst-supporting structure according to any one of claims 10 to 13.
  15. 請求項１０～１３のいずれかに記載の光触媒担持構造体により窒素酸化物を分解及び／又は除去する方法。 A method for decomposing and / or removing nitrogen oxides with the photocatalyst-supporting structure according to any one of claims 10 to 13.
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