JP5569523B2 - Photocatalyst-coated body and photocatalyst coating liquid - Google Patents

Description

Related applications

  This application claims the priority of Japanese Patent Application No. 2009-152493 filed on June 26, 2009, the specification of which is incorporated herein by reference. Is done.

The present invention is capable of decomposing harmful gases, self-cleaning by rain and water washing, easy to wash, VOC (volatile organic compounds (volatile
organic compounds)) relates to a photocatalyst-coated body having photocatalytic functions such as degradability, antibacterial properties, antifungal properties, and antiviral properties. Furthermore, the present invention forms a coating layer on members constituting the exterior, interior, etc., thereby decomposing harmful gases, self-cleaning by rain / washing, ease of washing, VOC degrading, antibacterial, antifungal. The present invention relates to a photocatalyst coating solution capable of imparting a photocatalytic function such as antiviral properties.

  In recent years, photocatalysts such as titanium oxide have been used for building structures, structures, vehicles, members constituting them, composite materials, and the like.

  For outdoor use, a base material surface is supported with a photocatalyst to give the base material a function of decomposing harmful substances such as NOx and SOx using light energy. Further, the layer surface that has become hydrophilic upon light irradiation has a so-called self-cleaning function in which attached dirt is washed away by rain.

  Also, for indoor use, by supporting a photocatalyst on the surface of the base material, the base material is given a function of decomposing toxic substances such as VOC using light energy, an antibacterial function, and an antifungal function. It has been done to give antiviral function.

  Various proposals have been made to realize a higher photocatalytic function. For example, Japanese Patent Application Laid-Open No. 2004-051644 (Patent Document 1) proposes the use of a coating agent using a photocatalyst and silica having a particle diameter smaller than that of a hydrophobic resin emulsion. When this aqueous dispersion of the coating agent is applied to the substrate, the photocatalyst particles and silica particles move toward the surface of the photocatalyst layer and solidify before drying. As a result, more photocatalyst particles are present on the surface of the photocatalyst layer, and the photocatalytic function is enhanced.

  Japanese Patent Laid-Open No. 2004-97630 (Patent Document 2) is known as another technique for improving the photocatalytic function by moving photocatalyst particles toward the surface of the photocatalyst layer. According to this publication, a photocatalyst layer containing photocatalyst particles is provided on a sunshade base material, and the photocatalyst particles have a high concentration in the surface direction of the layer. A specific method for this is to use photocatalyst particles modified with a hydrophobic silane compound or hydrosilane to lower the surface energy as photocatalyst particles, and phenyl having a relatively large surface energy as a binder for binding the photocatalyst particles to each other. Using a group-containing silicone resin, the surface energy of the photocatalyst particles is made smaller than the surface energy of the binder. Then, a coating agent in which the photocatalyst particles and the binder are dispersed in a mixed solvent of toluene-isopropanol-butyl cellosolve in which they are easily dispersed is used. When the organic solvent dispersion of the coating agent is applied to the substrate, the photocatalyst particles move toward the surface of the photocatalyst layer and solidify until the substrate is dried. As a result, more photocatalyst particles are present on the surface of the photocatalyst layer, and the photocatalytic function is enhanced.

  Furthermore, JP2009-279666 (Patent Document 3) proposes a coating agent containing a tetrafluoroethylene-hexafluoropropylene copolymer emulsion as a binder. In the photocatalyst layer formed by applying this coating agent, it is disclosed that the binder is unevenly distributed in the direction of the interface with the base material, and the photocatalyst is relatively unevenly distributed on the surface of the photocatalyst layer. There is.

  In addition, if the photocatalyst particles are present at a high concentration on the surface of the photocatalyst layer and are present at a relatively low concentration on the interface side of the photocatalyst layer with the base material, the influence of the photocatalyst on the base material is reduced. It is advantageous. When the base material itself has design properties, the base material is hardly decomposed and deteriorated by the photocatalyst. Further, in order to add a color pigment to the photocatalyst layer itself and cover the color of the base material to bring out the design of the photocatalyst layer, the photocatalyst layer needs to have a certain thickness. Even in this case, the fact that the photocatalyst is small on the interface side with the base material can reduce the influence thereof even though a relatively large amount of the photocatalyst is supported on the base material, It can be said that it is preferable.

Japanese Patent Laid-Open No. 2004-051644 JP 2004-97630 A JP 2009-279666

  The present inventors have recently developed a photocatalyst layer formed of a coating liquid containing photocatalytic metal oxide particles and a resin emulsion on silica particles coated or modified with a substance having a hydrophobic group. It has been found that the photocatalyst function is remarkably improved as compared with the photocatalyst layer formed using the particles as they are. Such improvement of the photocatalytic function is due to the fact that the concentration of the metal element of the photocatalytic metal oxide particles in the photocatalytic layer shows a concentration gradient that gradually increases from the center of the layer toward the outermost layer. The present invention is based on such knowledge.

  Accordingly, an object of the present invention is to provide a photocatalyst-coated body excellent in photocatalytic function and a photocatalyst coating liquid used for the formation thereof.

  And the photocatalyst coating body by this invention is a photocatalyst coating body provided with the photocatalyst layer on the base-material surface, Comprising: The said photocatalyst layer is a photocatalytic metal oxide particle, a silica particle, the dried material of a resin emulsion, The silica particles are coated or modified with a substance having a hydrophobic group.

  The photocatalytic coating liquid according to the present invention includes photocatalytic metal oxide particles, silica particles, a resin emulsion, and a solvent, and the silica particles are coated or modified with a substance having a hydrophobic group. Yes.

  The photocatalyst coating body by this invention is excellent in a photocatalyst function. Furthermore, according to a preferred embodiment of the present invention, when the photocatalyst layer is transparent, the substrate design can be utilized when the photocatalyst layer is transparent, and the photocatalyst layer contains a color pigment. When it exists, it is excellent in base-material concealing property and a design can be provided with a photocatalyst layer.

It is the spectrum of the elemental analysis by the energy dispersive X ray spectroscopy performed about the position of the surface vicinity of the photocatalyst layer of the photocatalyst coating body obtained in Example 1. FIG. It is the spectrum of the analysis of the element by the energy dispersive X ray spectroscopy performed about the position of the center vicinity of the photocatalyst layer of the photocatalyst coating body obtained in Example 1. FIG. It is the spectrum of the elemental analysis by energy dispersive X-ray spectroscopy performed about the position of the interface vicinity of the base material of the photocatalyst coating body obtained in Example 1, and a photocatalyst layer.

Photocatalyst-coated body The photocatalyst-coated body according to the present invention is a photocatalyst-coated body having a photocatalyst layer on a substrate surface, and the photocatalyst layer includes photocatalytic metal oxide particles, silica particles, and a dried resin emulsion. And the silica particles are coated or modified with a substance having a hydrophobic group. Surprisingly, the photocatalytic activity can be significantly increased by using silica particles coated or modified with a substance having a hydrophobic group as compared with the case where silica particles are added as they are. Moreover, the external appearance change of a coating body is suppressed over a long period of time.

  In addition, the photocatalyst layer as used in the field of this invention means the part formed by applying the coating liquid containing a photocatalyst particle to the base-material surface. As long as the photocatalyst particles exist in the portion, any form may be used. That is, it may be completely film-shaped or partially film-shaped. Moreover, it may exist discretely in the shape of islands on the substrate surface.

  In the photocatalyst-coated body according to the present invention, the concentration of the metal element of the photocatalytic metal oxide particles in the outermost layer of the photocatalyst layer is higher than that in the center of the layer. According to a preferred embodiment of the present invention, the concentration gradient of the metal element of the photocatalytic metal oxide particles in the photocatalyst layer increases from the vicinity of the interface with the substrate to the outermost layer. It is considered that the strength of the photocatalytic function as a coated body is mainly governed by the amount of the photocatalytic metal oxide present in the outermost layer. Therefore, the photocatalytic function of the coated body according to the present invention in which the photocatalytic oxide particles are unevenly distributed in the outermost layer of the photocatalytic layer is high. In addition, the coated body according to the present invention, in which the photocatalytic metal oxide particles are present at a high concentration on the surface of the photocatalyst layer and is present at a relatively low concentration on the interface side with the base material of the photocatalyst layer, This is advantageous because the influence on the is small. In the coated body according to the present invention, when the base material itself has design properties, the base material is hardly decomposed and deteriorated by the photocatalyst. In addition, the coated body according to the present invention in which the photocatalyst is small on the interface side with the base material reduces the influence of the photocatalyst on the base material even though a relatively large amount of the photocatalyst is supported on the base material. This is advantageous in that

  According to a preferred embodiment of the present invention, the substance having a hydrophobic group is a silane having a hydrophobic group and / or a silicone having a hydrophobic group. Since these substances have a siloxane bond in common with the silica particles, the silica surface can be easily coated and modified with these substances by a coupling treatment or the like.

  According to a preferred embodiment of the present invention, the film thickness of the photocatalyst layer is more than 3 μm and less than 3 mm. By exceeding 3 μm, the concealment property of the ultraviolet ray by the photocatalyst layer is enhanced, and the influence of the ultraviolet ray on the substrate can be reduced. As a result, it is possible to effectively suppress deterioration of the substrate due to ultraviolet rays. Further, when the photocatalyst layer contains a color pigment, the substrate can be sufficiently concealed, and a design can be imparted to the substrate by the photocatalyst layer. Moreover, while being less than 3 mm, while the basic property as a coating film is maintained, the coating film formation in an appropriate curing time is attained.

  According to a preferred embodiment of the present invention, the photocatalyst layer is transparent. The design which a base material has can be utilized as it is because a photocatalyst layer is transparent. Here, as the degree of “transparency”, it is more preferable to ensure the linear transmittance of the photocatalyst layer at a wavelength of 550 nm of 50% or more, preferably 70% or more, more preferably 80% or more.

  According to a preferred form of the present invention, the dry matter content of the resin emulsion is 50% or more, preferably 70% or more, based on the total mass of the solid content of the resin emulsion, photocatalytic metal oxide particles, and silica particles. Most preferably, it is 85% or more. By setting it as such a content, it becomes easy to ensure the transparency of a photocatalyst layer.

  According to one preferred embodiment of the present invention, the photocatalyst layer may further contain a color pigment. Since the photocatalyst layer is colored with a color pigment, the concealability of the substrate can be obtained, and a design can be imparted to the substrate by the photocatalyst layer.

  According to a preferred embodiment of the present invention, the resin emulsion is a silicone emulsion and / or a fluororesin emulsion. By using these emulsions, an excellent photocatalytic decomposition function is exhibited even when used under severe outdoor conditions, and changes in the appearance of the base material are suppressed over a long period of time.

  According to a preferred embodiment of the present invention, the average particle size of the resin emulsion is larger than the average particle size of the photocatalytic metal oxide particles and the silica particles. This is preferable because the ratio of the photocatalytic metal oxide particles moving toward the surface of the photocatalyst layer is considered to increase.

  According to a preferred embodiment of the present invention, the photocatalytic metal oxide particles include titanium oxide such as anatase type titanium oxide, rutile type titanium oxide, brookite type titanium oxide, tin oxide, zinc oxide, strontium titanate, tungsten oxide, Particles of metal oxides such as cerium oxide, particles in which these particles are combined, and these particles are combined or doped with copper, platinum, iron, palladium, silver, gold, cuprous oxide, cupric oxide, etc. Particles obtained by coating or modifying the surface of these particles with silane, silicone or hydrolyzable metal salt can be suitably used.

  According to a preferred embodiment of the present invention, the photocatalytic metal oxide particles preferably have an average particle size of 10 nm or more and less than 100 nm, more preferably 10 nm or more and 60 nm or less. The average particle diameter is calculated as a number average value obtained by measuring the length of any 100 particles that enter a 200,000-fold field of view with a scanning electron microscope.

  As the shape of the particle, a true sphere is the best, but it may be approximately circular or elliptical, and the length of the particle in this case is approximately calculated as ((major axis + minor axis) / 2). Within this range, weather resistance and harmful gas decomposability are efficiently exhibited, and transparency, coating strength, and the like are improved.

  According to a preferred embodiment of the present invention, the photocatalytic metal oxide particles preferably have an average crystallite size of 3 nm or more and less than 30 nm, more preferably 5 nm or more and 20 nm or less. The average particle diameter is calculated by the Scherrer equation from the integral width of the three strong lines of the X-ray profile obtained by the powder X-ray diffraction method.

  According to a preferred embodiment of the present invention, the content of the photocatalytic metal oxide particles is a dry mass (solid content mass) with respect to the total mass of the resin emulsion, the photocatalytic metal oxide particles, and the silica particles. It is more than 0.1% by mass and less than 15% by mass, more preferably more than 0.5% by mass and less than 5% by mass.

  According to a preferred embodiment of the present invention, the silica particles preferably have an average particle size of more than 5 nm and 100 nm or less, more preferably more than 10 nm and 50 nm or less. The average particle diameter is calculated as a number average value obtained by measuring the length of any 100 particles that enter a 200,000-fold field of view with a scanning electron microscope. As the shape of the particle, a true sphere is the best, but it may be approximately circular or elliptical, and the length of the particle in this case is approximately calculated as ((major axis + minor axis) / 2). Use of such silica particles is advantageous because the photocatalytic degradation activity can be improved while improving the coating film strength.

  As the substance having a hydrophobic group for coating or modifying the silica particles, for example, a substance having a functional group and a hydrophobic group for bonding to the silica particles can be suitably used. Specifically, hydrolyzable silane, hydrolyzable silicone, vinyl group-containing fluororesin, vinyl group-containing hydrocarbon resin, (meth) acryl functional group-containing fluororesin, acrylic functional group-containing hydrocarbon resin, epoxy functional group-containing Fluorine resins, epoxy functional group-containing hydrocarbon resins, silyl group-containing fluororesins, silyl group-containing hydrocarbon resins, substances in which these substances are substituted with modifying groups, block copolymers of these substances, and the like can be suitably used. . The amount of the substance used for the coating or modification treatment is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass with respect to the amount of silica.

  Examples of the hydrolyzable silane having a hydrophobic group include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxy. Silane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyl Trimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysila 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3 -Hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltrie Xysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxy Silane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxypropyltri Trialkoxysilanes such as isopropoxysilane, 3-ureidopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxy Sisilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n-pentyl Dimethoxysilane, di-n-pentyldiethoxysilane, di-n-hexyldimethoxysilane, di-n-hexyldiethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane, di-n- Octyldimethoxysilane, di-n-octyldiethoxysilane, di-n-cyclohexyldimethoxysilane, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxy Dialkoxy silanes such as silane, trimethyl silane, mono-alkoxysilanes such as trimethyl silane, and the like. Moreover, these can be used individually or in mixture of 2 or more types.

  As the hydrolyzable silicone having a hydrophobic group used in the present invention, a (partial) hydrolyzed / condensed product of the above silane can be suitably used.

  As the resin emulsion used in the present invention, for example, emulsions such as fluororesin, silicone, acrylic silicone, vinyl acetate, vinyl acetate acrylic, acrylic urethane, acrylic, epoxy, vinyl vinyl chloride, vinylidene chloride, SBR latex and the like can be used.

  Examples of the fluororesin emulsion include polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, perfluorocyclopolymer, vinyl ether-fluoroolefin copolymer, vinyl ester-fluoroolefin copolymer, tetrafluoroethylene-vinyl ether copolymer, chlorotrifluoroethylene-vinyl ether copolymer, cross-linked tetrafluoroethylene urethane, Tetrafluoroethylene epoxy crosslinked product, tetra Le Oro ethylene acrylic crosslinked emulsion polymers containing tetrafluoroethylene melamine crosslinked body and the like fluoro group can be suitably used.

  Silicone emulsions include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, methyltribromosilane, methyltriisopropoxysilane, methyltrit-butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyl Trichlorosilane, ethyltribromosilane, ethyltriisopropoxysilane, ethyltri-t-butoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltrichlorosilane, n-propyltribromosilane, n-propyl Triisopropoxysilane, n-propyltri-t-butoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltrichlorosilane, n-hexyltri Romsilane, n-hexyltriisopropoxysilane, n-hexyltri-t-butoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltrichlorosilane, n-decyltribromosilane, n-decyltriisopropoxy Silane, n-decyltri-t-butoxysilane, n-octatrimethoxysilane, n-octatriethoxysilane, n-octatrichlorosilane, n-octatribromosilane, n-octatriisopropoxysilane, n-octatrit-butoxysilane , Phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane, phenyltribromosilane, phenyltriisopropoxysilane, phenyltri-t-butoxysilane, dimethyldichlorosilane, dimethyldibromide Silane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenylmethyldichlorosilane, phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldi Ethoxysilane, vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrit-butoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltridibromosilane, trifluoropropyl Trimethoxysilane, trifluoropropyltriethoxysilane, vinyltrichlorosilane, trifluoropropyltriisopropyl Lopoxysilane, trifluoropropyltri-t-butoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxy Silane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropyltri-t-butoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacrylic Roxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, γ-methacryloxypropyltri-t-butoxysilane, γ-aminopropylmethyldi Toxisilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminomethacryloxypropyltri-t-butoxysilane, γ -Methylcaptopropylmethyldimethoxysilane, γ-methylcaptopropylmethyldiethoxysilane, γ-methylcaptopropyltrimethoxysilane, γ-methylcaptopropyltriethoxysilane, γ-methylcaptopropyltriisopropoxysilane, γ-methylcapto Hydrolysis of propyltri-t-butoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, dehydration condensation polymer, etc. Rujon can be suitably used.

  As the color pigment that the coated body according to the present invention may contain, an inorganic pigment is preferable because it can easily suppress a change in appearance over a long period of time. Inorganic pigments include metal oxides such as titanium oxide, zinc white, bengara, chromium oxide, cobalt blue and iron black, metal hydroxides such as alumina white and yellow iron oxide, ferrocyan compounds such as bitumen, Lead chromate series such as chrome lead, zinc chromate, molybdenum red, sulfides such as zinc sulfide, vermilion, cadmium yellow, cadmium red, sulfates such as selenium compounds, barite, precipitated barium sulfate, heavy calcium carbonate, Carbonates such as precipitated calcium carbonate, silicates such as hydrous silicate, clay and ultramarine, carbons such as carbon black, metal powders such as aluminum powder, bronze powder and zinc powder, mica and titanium oxide systems Pearl pigment system.

  In the coated body according to the present invention, the photocatalyst layer may contain inorganic oxide particles other than silica particles. The inorganic oxide particles are not particularly limited as long as they are inorganic oxide particles capable of forming a layer together with the photocatalyst particles, and various inorganic oxide particles can be used. Examples of such inorganic oxide particles include alumina, zirconia, ceria, yttria, tin oxide, iron oxide, manganese oxide, nickel oxide, cobalt oxide, hafnia and other single oxide particles; and barium titanate, Examples thereof include composite oxide particles such as calcium silicate, aluminum borate, and potassium titanate.

  According to a preferred embodiment of the present invention, at least one selected from the group consisting of vanadium, iron, cobalt, nickel, palladium, zinc, ruthenium, rhodium, copper, silver, platinum and gold is used to develop higher photocatalytic ability. The coated body may contain a metal compound and / or a metal compound comprising the metal. These compounds may be mixed in a coating liquid described later and exist in the photocatalyst layer, or these compounds can be present in the photocatalyst layer by supporting them on the photocatalyst particles.

  The photocatalyst layer of the coated body according to the present invention may contain an organic antifungal agent. Specific examples thereof include organic nitrogen sulfur compounds, pyrithion compounds, organic iodine compounds, triazine compounds, isothiazoline compounds. , Imidazole compounds, pyridine compounds, nitrile compounds, thiocarbamate compounds, thiazole compounds, organic iodine compounds, and disulfide compounds are used alone or as a mixture. Since many antifungal agents generally have an effect of preventing algae, addition of the antifungal agent can be expected to suppress both mold and algae.

  The photocatalyst layer of the coated body according to the present invention may contain an ultraviolet absorber. The content of the ultraviolet absorber is not limited as long as the weather resistance can be improved without inhibiting the photocatalytic activity and / or hydrophilic expression, for example, 0.001 to 10% by mass, preferably 0 to the photocatalyst. 0.01 to 5% by mass.

  Usable examples of the ultraviolet absorber usable in the present invention include benzophenone-based, benzotriazole-based, and triazine-based ultraviolet absorbers.

  In particular, a triazine ultraviolet absorber is preferable because it is chemically stable. Specifically, hydroxyphenyltriazine or a derivative thereof can be suitably used as the triazine-based ultraviolet absorber.

  Specific examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, and 2-hydroxy-4. -N-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2,2 ' -Dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'dimethoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy- 4-methoxy-2'- Ruboxybenzophenone, 2-hydroxy-4-stearyloxybenzophenone, octabenzone, and 2-hydroxy-4-acryloxybenzophenone, 2-hydroxy-4-methacryloxybenzophenone, 2-hydroxy-5-acryloxybenzophenone, 2-hydroxy -5-methacryloxybenzophenone, 2-hydroxy-4- (acryloxy-ethoxy) benzophenone, 2-hydroxy-4- (methacryloxy-ethoxy) benzophenone, 2-hydroxy-4- (methacryloxy-diethoxy) benzophenone, 2-hydroxy- Examples thereof include polymerizable benzophenone-based ultraviolet absorbers such as 4- (acryloxy-triethoxy) benzophenone and (co) polymers thereof.

Specific examples of the benzotriazole-based UV absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-5′-tert-butylphenyl) benzo. Triazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy- 3,5-di-tert-octylphenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (α, α′-dimethylbenzyl) phenyl] benzotriazole), methyl-3- [3 -Tert-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate and polyethylene glycol Condensate with Cole (molecular weight 300) (product name: TINUVIN-1130 manufactured by Ciba Geigy Co., Ltd.), isooctyl-3- [3- (2H-benzotriazol-2-yl) -5-tert-butyl-4 -Hydroxyphenyl] propionate (manufactured by Ciba Geigy Japan, product name: TINUVIN-384), 2- (3-dodecyl-5-methyl-2-hydroxyphenyl) benzotriazole (manufactured by Ciba Geigy Japan, product name: TINUVIN-571), 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert) -Amylphenyl) benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl] benzotriazole, 2,2-methylenebis [4- (1,1 , 3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1- Phenylethyl) phenol (manufactured by Ciba Geigy Japan, product name: TINUVIN-900), and 2- (2′-hydroxy-5′-methacryloxyethylphenyl) -2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd.) Product name: RUVA-93), 2- (2′-hydroxy-5′-methacryloxyethyl-3-tert-butylphenyl) -2H-benzotriazole, 2- (2′-H Loxy-5'-methacrylyloxypropyl-3-tert-butylphenyl) -5-chloro-2H-benzotriazole, 3-methacryloyl-2-hydroxypropyl-3- [3 '-(2 "-benzotriazolyl) ) -4-hydroxy-5-tert-butyl] phenylpropionate (manufactured by Ciba-Geigy Japan, product name: CGL-104), and other polymerizable benzotriazole ultraviolet absorbers and their (co) polymers. Others, TINUVIN-384-2 (product name, manufactured by Ciba-Geigy Corporation of Japan), TINUVIN-99-2 (product name, manufactured by Ciba-Geigy Corporation of Japan), TINUVIN-109 (product name, manufactured by Ciba-Geigy Corporation of Japan) , TINUVIN-328 (product name, manufactured by Nippon Ciba-Geigy Co., Ltd.), TINUVIN-928 (product name, Nippon Ciba Made Iggy Co., Ltd.), and the like.

  Moreover, according to the preferable aspect of this invention, the photocatalyst layer may further contain light stabilizers, such as a hindered amine type and / or a hindered phenol type. The photocatalyst layer of the present invention is preferable because it exhibits excellent weather resistance and light resistance due to a synergistic effect with the ultraviolet absorber.

  In particular, according to a preferred embodiment of the present invention, a hydroxyphenyl triazine compound may be blended as an ultraviolet absorber and a hindered amine compound as a light stabilizer. By this combination, the absorption performance of ultraviolet rays having a short wavelength of less than 380 nm by the photocatalyst layer is stabilized.

  In the present invention, the content of the light stabilizer in the photocatalyst layer is not limited as long as the weather resistance can be improved without inhibiting the expression of photocatalytic activity and / or hydrophilicity. It is preferable to contain 001-10 mass%, Preferably 0.01-5 mass% is contained.

  Specific examples of the hindered amine light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis (2,2,6,6-tetramethylpiperidyl) sebacate, bis (1, 2,2,6,6-pentamethyl-4-piperidyl) 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-butylmalonate, 1- [2- [3- (3 5-Di-tert-butyl-4-hydroxyphenyl) propynyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propynyloxy] -2,2,6 6-tetramethylpiperidine, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2,2,6,6-pentamethyl-4-piperidyl-sebake Mixture (manufactured by Ciba Geigy Japan, product name: TINUVIN-292), bis (1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, TINUVIN-123 (product name, Japan) Ciba-Geigy Co., Ltd.), TINUVIN-111FDL (product name, manufactured by Nippon Ciba-Geigy Co., Ltd.), TINUVIN 292 (product name, manufactured by Ciba-Geigy Corp. Japan), and 1,2,2,6,6-pentamethyl-4- Piperidyl methacrylate, 1,2,2,6,6-pentamethyl-4-piperidyl acrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl Acrylate, 1,2,2,6,6-pentamethyl-4-iminopiperidyl methacrylate, 2,2,6 6, -tetramethyl-4-iminopiperidyl methacrylate, 4-cyano-2,2,6,6-tetramethyl-4-piperidyl methacrylate, 4-cyano-1,2,2,6,6-pentamethyl-4- Examples thereof include polymerizable hindered amine ultraviolet absorbers such as piperidyl methacrylate and (co) polymers thereof.

  Specific examples of the hindered phenol light stabilizer include bis (3,5-tert-butyl) -4-hydroxytoluene, TINUVIN-144 (product name, manufactured by Ciba Geigy Japan, Inc.), and the like. it can.

Photocatalyst coating liquid According to another aspect of the present invention, there is provided a photocatalyst coating liquid which is preferable for the formation of the above-described coated body according to the present invention. The coating liquid comprises photocatalytic metal oxide particles, silica particles, and a resin. It comprises an emulsion and a solvent, and the silica particles are coated or modified with a substance having a hydrophobic group.

The photocatalytic metal oxide particles, the silica particles, and the resin emulsion contained in the coating liquid according to the present invention are substantially the same except that they are in a state of constituting the liquid composition and the components constituting the above-mentioned coated body. It may be the same. Moreover, what was mentioned as a preferable aspect about these components may be similarly added as a preferable thing in the coating liquid by this invention.
The composition of the coating solution may be any material that realizes the above-described composition after drying. Therefore, although the following explanation has been partly explained, the following explanation will be given regardless of duplication for the sake of clarity.

According to a preferred embodiment of the present invention, the solid content of the resin emulsion is 50% or more, preferably 70% or more, most preferably based on the total mass of the solid content of the resin emulsion, photocatalytic metal oxide particles and silica particles. Preferably, it should be 85% or more.

  Moreover, in order to implement | achieve the coating body containing a color pigment, according to the preferable form of this invention, the coating liquid by this invention can contain a color pigment further.

  According to a preferred embodiment of the present invention, the resin emulsion is a silicone emulsion and / or a fluororesin emulsion.

  According to a preferred embodiment of the present invention, the average particle size of the resin emulsion in the coating solution is larger than the average particle size of the photocatalytic metal oxide particles and the silica particles. Thereby, it is considered that the rate at which the photocatalytic metal oxide particles move toward the surface of the photocatalyst layer is increased.

  According to a preferred embodiment of the present invention, the photocatalytic metal oxide particles include titanium oxide such as anatase type titanium oxide, rutile type titanium oxide, brookite type titanium oxide, tin oxide, zinc oxide, strontium titanate, tungsten oxide, Particles of metal oxides such as cerium oxide, particles in which these particles are combined, and these particles are combined or doped with copper, platinum, iron, palladium, silver, gold, cuprous oxide, cupric oxide, etc. Particles obtained by coating and modifying the surfaces of these particles with silane, silicone or hydrolyzable metal salt can be suitably used.

  According to a preferred embodiment of the present invention, the photocatalytic metal oxide particles preferably have an average particle size of 10 nm or more and less than 100 nm, more preferably 10 nm or more and 60 nm or less. The average particle diameter is calculated as a number average value obtained by measuring the length of any 100 particles that enter a 200,000-fold field of view with a scanning electron microscope.

  As the shape of the particle, a true sphere is the best, but it may be approximately circular or elliptical, and the length of the particle in this case is approximately calculated as ((major axis + minor axis) / 2). Within this range, weather resistance and harmful gas decomposability are efficiently exhibited, and transparency, coating strength, and the like are improved.

  According to a preferred embodiment of the present invention, the photocatalytic metal oxide particles preferably have an average crystallite size of 3 nm or more and less than 30 nm, more preferably 5 nm or more and 20 nm or less. The average particle diameter is calculated by the Scherrer equation from the integral width of the three strong lines of the X-ray profile obtained by the powder X-ray diffraction method.

  According to a preferred embodiment of the present invention, the content of the photocatalytic metal oxide particles in the coating liquid is a dry mass (solid content mass), and is a total of the resin emulsion, the photocatalytic metal oxide particles, and the silica particles. More than 0.1% by mass and less than 15% by mass, and more preferably more than 0.5% by mass and less than 5% by mass.

  According to a preferred embodiment of the present invention, the silica particles preferably have an average particle size of more than 5 nm and 100 nm or less, more preferably more than 10 nm and 50 nm or less. The average particle diameter is calculated as a number average value obtained by measuring the length of any 100 particles that enter a 200,000-fold field of view with a scanning electron microscope. As the shape of the particle, a true sphere is the best, but it may be approximately circular or elliptical, and the length of the particle in this case is approximately calculated as ((major axis + minor axis) / 2).

  As the substance having a hydrophobic group for coating or modifying the silica particles, for example, a substance having a functional group and a hydrophobic group for bonding to the silica particles can be suitably used. Specifically, hydrolyzable silane, hydrolyzable silicone, vinyl group-containing fluororesin, vinyl group-containing hydrocarbon resin, (meth) acryl functional group-containing fluororesin, acrylic functional group-containing hydrocarbon resin, epoxy functional group-containing Fluorine resins, epoxy functional group-containing hydrocarbon resins, silyl group-containing fluororesins, silyl group-containing hydrocarbon resins, substances in which these substances are substituted with modifying groups, block copolymers of these substances, and the like can be suitably used. . The amount of the substance used for the coating or modification treatment is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass with respect to the amount of silica.

  As the resin emulsion used in the present invention, for example, emulsions such as fluororesin, silicone, acrylic silicone, vinyl acetate, vinyl acetate acrylic, acrylic urethane, acrylic, epoxy, vinyl vinyl chloride, vinylidene chloride, SBR latex and the like can be used.

  When the coating liquid according to the present invention contains a color pigment, an inorganic pigment is preferable as the color pigment because it is easy to suppress a change in appearance over a long period of time. Inorganic pigments include metal oxides such as titanium oxide, zinc white, bengara, chromium oxide, cobalt blue and iron black, metal hydroxides such as alumina white and yellow iron oxide, ferrocyan compounds such as bitumen, Lead chromate series such as chrome lead, zinc chromate, molybdenum red, sulfides such as zinc sulfide, vermilion, cadmium yellow, cadmium red, sulfates such as selenium compounds, barite, precipitated barium sulfate, heavy calcium carbonate, Carbonates such as precipitated calcium carbonate, silicates such as hydrous silicate, clay and ultramarine, carbons such as carbon black, metal powders such as aluminum powder, bronze powder and zinc powder, mica and titanium oxide systems Pearl pigment system.

  The coating liquid according to the present invention may contain inorganic oxide particles other than silica particles. The inorganic oxide particles are not particularly limited as long as they are inorganic oxide particles capable of forming a layer together with the photocatalyst particles, and various inorganic oxide particles can be used. Examples of such inorganic oxide particles include alumina, zirconia, ceria, yttria, tin oxide, iron oxide, manganese oxide, nickel oxide, cobalt oxide, hafnia and other single oxide particles; and barium titanate, Examples thereof include composite oxide particles such as calcium silicate, aluminum borate, and potassium titanate.

  According to a preferred embodiment of the present invention, the coating liquid according to the present invention is made of vanadium, iron, cobalt, nickel, palladium, zinc, ruthenium, rhodium, copper, silver, platinum and gold in order to develop higher photocatalytic ability. It may contain at least one metal selected from the group consisting of and / or a metal compound comprising the metal.

  The solvent used in the photocatalyst coating liquid according to the present invention is not particularly limited, but water, alcohols such as methanol, ethanol, propanol and butanol, mixed solvents of water and alcohol, and the like can be particularly preferably used. In particular, it is preferable to use water as a solvent because it can effectively prevent the odor and environmental pollution caused by the volatilization and evaporation of organic substances during coating film formation.

  Further, the solid content concentration of the photocatalyst coating liquid is not particularly limited, but it is preferably 3 to 70% by mass, more preferably 5 to 60% by mass, and most preferably 10 to 50% by mass because the application becomes easy. The components in the photocatalyst coating solution are analyzed by separating the coating solution into particle components and filtrate by ultrafiltration, and analyzing each by infrared spectroscopic analysis, gel permeation chromatography, fluorescent X-ray spectroscopic analysis, etc. It can be evaluated by analyzing the spectrum.

  In addition, various additives can be mix | blended with the photocatalyst coating liquid of this invention.

  According to a preferred embodiment of the present invention, the photocatalyst coating liquid can contain a film forming aid having a boiling point of 100 ° C. or higher, which is soluble in water or can be uniformly dispersed in water. This film-forming auxiliary agent remains in the film even after most of the water is vaporized, and can promote fusion and dissolve the film-forming temperature by dissolving the resin emulsion interface. Specifically, alcohols such as 1-butanol, isobutyl alcohol, 2-pentanol, 3-pentanol, isopentyl alcohol, methyl lactate, ethyl lactate, and 3-methyl-3-methoxybutanol, 1,2-propane Polyols such as diol, 1,3-butanediol 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, glycerin, trimethylolpropane, Ethylene glycol derivatives such as 2-butoxyethanol, 2-phenoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, diethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-methoxy-2 Propylene glycol derivatives such as methyl ethyl acetate, 1-ethoxy-2-methyl ethyl acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether acetate, 3-methoxybutyl Butylene glycol derivatives such as acetate, ketones such as cyclohexanone, butyl acetate, isobutyl acetate, γ-butyrolactone, propylene carbonate, dibutyl phthalate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, etc. Examples thereof include esters. In particular, alkylene glycol derivatives such as 2-ethoxyethyl acetate, 2-butoxyethyl acetate, diethylene glycol monobutyl ether acetate, 1-ethoxy-2-methylethyl acetate, dipropylene glycol monomethyl ether acetate are preferable.

  The amount of the film-forming aid added to the coating liquid according to the present invention is preferably 0 to 20 parts by weight, particularly 1 to 15 parts by weight based on 100 parts by weight of the silicone resin.

  The coating liquid according to the present invention may contain a surfactant as an optional component. In a preferred embodiment of the present invention, the surfactant is added in an amount of less than 10 parts by weight, more preferably about 0.1 to 2 parts by weight with respect to 1 part by weight of the photocatalyst particles.

  Examples of surfactants that can be added to the coating liquid according to the present invention include sulfonic acid polyoxyethylene alkylphenyl ether ammonium salt, sulfonic acid polyoxyethylene alkylphenyl ether sodium salt, fatty acid sodium soap, fatty acid potassium soap, dioctyl sulfosuccinic acid Sodium, alkyl sulfate, alkyl ether sulfate, alkyl sulfate soda salt, alkyl ether sulfate soda salt, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether sulfate soda salt, alkyl sulfate TEA salt, polyoxyethylene alkyl ether sulfate TEA salt, 2-ethylhexylalkylsulfate sodium salt, sodium acylmethyl taurate Sodium lauroylmethyl taurate, sodium dodecylbenzene sulfonate, disodium lauryl sulfosuccinate, disodium lauryl polyoxyethylene sulfosuccinate, polycarboxylic acid, oleoyl sarcosine, amide ether sulfate, lauroyl sarcosinate, sulfo FA ester sodium salt Anionic surfactants such as: polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester , Polyoxyethylene alkylphenol ether, polyoxyethylene nonylphenyl ether, polyoxyethylene Tylene octyl phenyl ether, polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene alkyl phenyl ether, polyoxyethylene oleate, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, polyether modified silicone, polyester modified silicone, Sorbitan laurate, sorbitan stearate, sorbitan palmitate, sorbitan oleate, sorbitan sesquioleate, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan oleate, glycerol Stearate, polyglycerin fatty acid ester, alkylalkylolamide, Uric acid diethanolamide, oleic acid diethanolamide, oxyethylene dodecylamine, polyoxyethylene dodecylamine, polyoxyethylene alkylamine, polyoxyethylene octadecylamine, polyoxyethylene alkylpropylenediamine, polyoxyethyleneoxypropylene block polymer, polyoxy Nonionic surfactants such as ethylene stearate; amphoteric surfactants such as dimethylalkylbetaine, alkylglycine, amidebetaine, imidazoline, octadecyldimethylbenzylammonium chloride, alkyldimethylbenzylammonium chloride, tetradecylmethylbenzylammonium chloride, dioleyl Dimethylammonium chloride, 1-hydroxyethyl-2-alkyl Imidazoline quaternary salt, alkylisoquinolinium bromide, polymeric amine, octadecyltrimethylammonium chloride, alkyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, alkylimidazoline quaternary salt, dialkyldimethyl And cationic surfactants such as ammonium chloride, octadecylamine acetate, tetradecylamine acetate, alkylpropylenediamine acetate, and didecyldimethylammonium chloride.

Manufacturing method of photocatalyst coating body The photocatalyst coating body of this invention can be manufactured by apply | coating the said photocatalyst coating liquid on a base material. As a method for coating the photocatalyst layer, generally used methods such as brush coating, roller, spray, roll coater, flow coater, dip coating, flow coating, and screen printing can be used. After applying the coating liquid to the substrate, it may be dried at room temperature, or may be heat-dried as necessary.

Base Material The base material used in the present invention may be various materials regardless of inorganic materials, organic materials, and multilayer materials, and the shape thereof is not limited. Preferred examples of the substrate from the viewpoint of materials include metals, ceramics, glass, plastics, rubber, stones, cement, concrete, fibers, fabrics, wood, paper, combinations thereof, laminates thereof, Examples thereof include those having at least one layer of coating on the surface. Preferred examples of base materials from the viewpoint of applications include building materials, building exteriors and interiors, window frames, window glass, structural members, exteriors and coatings of vehicles, exteriors of machinery and articles, dust covers and coatings, traffic signs, Various display devices, advertising towers, sound insulation walls for roads, sound insulation walls for railways, bridges, guard rail exteriors and paintings, tunnel interiors and paintings, insulators, solar cell covers, solar water heater heat collection covers, plastic houses, vehicle lighting Covers, outdoor lighting fixtures, tables, bathroom materials, kitchen panels, sinks, ranges, ventilation fans, air conditioning, filters, toilets, bathtubs, and films, sheets, seals and the like for attachment to the surface of the article.

  The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

Example 1.
(Silica particle surface coating treatment)
Hydrophobized silica particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of silica particles (average particle size 50 nm).
(Production of photocatalyst coating)
90 parts by mass of 1.3 parts by mass of anatase-type titanium oxide particles (average crystallite diameter: 10 nm), 8.7 parts by mass of the above-mentioned hydrophobized silica particles, and a silicone emulsion having a methylphenylsilyl group as a solid content A photocatalytic aqueous coating liquid having a solid content concentration of 25% by mass was prepared and dried on a transparent 2 mm thick soda lime glass substrate at 150 ° C. for 5 minutes to obtain a photocatalyst-coated body.
(Evaluation of coated photocatalyst)
When the photocatalyst layer of the obtained photocatalyst-coated body was observed in cross section, the film thickness was about 7 μm.
Further, the transmittance of light having a wavelength of 550 nm of the photocatalyst layer was 82%.
About this photocatalyst coating body, the photocatalyst decomposition activity was performed in accordance with the test method of JISR1703-2 "Self-cleaning performance test method of photocatalyst material-Part 2: Wet decomposition performance". As a result, the MB activity index was as good as 6.5.

  In addition, the cross section of the photocatalyst layer of the obtained photocatalyst-coated body is measured by energy dispersive X-ray spectroscopy (EDX) at a spot size of 1 μm × 0.5 μm near the surface, near the center, and near the interface with the substrate. The elements present were analyzed. The spectra were as shown in FIG. 1, FIG. 2, and FIG. 3, respectively. This analysis shows that Ti has a high concentration near the surface of the photocatalyst layer, a low concentration at the interface between the substrate and the photocatalyst layer, and a concentration around the center of the photocatalyst layer. It was.

Example 2
(Silica particle surface coating treatment)
Hydrophobized silica particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of silica particles (average particle size 50 nm).
(Production of photocatalyst coating)
A solid containing 1.3 parts by mass of anatase-type titanium oxide particles (average crystallite diameter: 10 nm), 8.7 parts by mass of the above-mentioned hydrophobized silica particles, and 90 parts by mass of a silicone emulsion having a dimethylsilyl group as a solid content A photocatalyst aqueous coating solution having a partial concentration of 25% by mass was prepared and dried on a transparent 2 mm thick soda lime glass substrate at 150 ° C. for 5 minutes to obtain a photocatalyst-coated body.
(Evaluation of coated photocatalyst)
When the photocatalyst layer of the obtained photocatalyst-coated body was observed in cross section, the film thickness was about 7 μm.
Further, the transmittance of light having a wavelength of 550 nm of the photocatalyst layer was 84%.
About this photocatalyst coating body, the photocatalytic decomposition activity was performed by the test method of JISR1703-2 "Self-cleaning performance test method of photocatalyst material-Part 2: Wet decomposition performance". As a result, the MB activity index was as good as 6.4.

Comparative Example 1
Anatase-type titanium oxide particles (average crystallite size 10 nm) 1.3 parts by mass, silica particles (average particle size 50 nm) 8.7 parts by mass, solid content concentration of 90 parts by mass of methylphenyl silicone emulsion as solid content 25 mass % Photocatalyst aqueous coating solution was prepared and dried on a transparent 2 mm thick soda lime glass substrate at 150 ° C. for 5 minutes to obtain a photocatalyst-coated body.
When the photocatalyst layer of the obtained photocatalyst-coated body was observed in cross section, the film thickness was about 7 μm.
Further, the transmittance of light having a wavelength of 550 nm of the photocatalyst layer was 83%.
About this photocatalyst coating body, the photocatalyst decomposition activity was performed in accordance with the test method of JISR1703-2 "Self-cleaning performance test method of photocatalyst material-Part 2: Wet decomposition performance". As a result, the MB activity index showed a low value of 1.1.

Example 3
(Silica particle surface coating treatment)
Hydrophobized silica particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of silica particles (average particle size 50 nm).
(Production of photocatalyst coating)
1.3 parts by mass of anatase-type titanium oxide particles (average crystallite diameter: 10 nm), 8.7 parts by mass of the above-mentioned hydrophobized silica particles, 45 parts by mass of methylphenyl silicone emulsion as a solid content, and 45 parts by mass of an inorganic pigment A photocatalyst aqueous coating solution having a solid content concentration of 40% by mass was prepared to obtain a photocatalyst paint.
Asbestos cement calcium silicate board cut to 150mm x 65mm (JIS
Epoxy resin-based primer was spray-coated on A5418) and dried at room temperature for 24 hours. Subsequently, an acrylic urethane paint was spray-coated on the asbestos-cement calcium silicate plate subjected to the primer coating described above, and dried at room temperature for 24 hours. Subsequently, the photocatalyst paint was brush-coated on an asbestos cement calcium silicate plate coated with acrylic urethane to obtain a coating.
(Evaluation of coated photocatalyst)
When the photocatalyst layer of the obtained photocatalyst-coated body was observed in cross section, the film thickness was about 40 μm.
About this photocatalyst coating body, the photocatalytic decomposition activity was performed in accordance with the test method of JISR1703-2 "Self-cleaning performance test method of photocatalyst material-Part 2: Wet decomposition performance". As a result, the MB activity index was as good as 6.0.
About the obtained photocatalyst coating body, the weather resistance test was done as follows. The photocatalyst-coated body was put into a sunshine weatherometer (S-300C, manufactured by Suga Test Instruments) defined in JIS B7753. After 100 hours had elapsed, the test piece was taken out and the appearance change before and after the addition was observed. As a result, no change was observed in the appearance.

Example 4
(Surface coating treatment of anatase-type titanium oxide particles)
Hydrophobized titanium oxide particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of anatase-type titanium oxide particles (average crystallite diameter: 10 nm).
(Silica particle surface coating treatment)
Hydrophobized silica particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of silica particles (average particle size 50 nm).
(Production of photocatalyst coating)
Solid content concentration containing 1.3 parts by mass of the hydrophobized titanium oxide particles, 8.7 parts by mass of the hydrophobized silica particles, and 90 parts by mass of a silicone emulsion having a methylphenylsilyl group as a solid content A 25% by mass photocatalytic aqueous coating solution was prepared and dried on a transparent 2 mm thick soda lime glass substrate at 150 ° C. for 5 minutes to obtain a photocatalyst-coated body.
(Evaluation of coated photocatalyst)
When the photocatalyst layer of the obtained photocatalyst-coated body was observed in cross section, the film thickness was about 7 μm.
Further, the transmittance of light having a wavelength of 550 nm of the photocatalyst layer was 84%.
About this photocatalyst coating body, the photocatalytic decomposition activity was performed in accordance with the test method of JISR1703-2 "Self-cleaning performance test method of photocatalyst material-Part 2: Wet decomposition performance". As a result, the MB activity index was as good as 9.3.

Experimental Example 5.
(Silica particle surface coating treatment)
Hydrophobized silica particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of silica particles (average particle size 50 nm).
(Production of photocatalyst coating)
90 parts by mass of 1.3 parts by mass of anatase-type titanium oxide particles (average crystallite diameter: 10 nm), 8.7 parts by mass of the above-mentioned hydrophobized silica particles, and a silicone emulsion having a methylphenylsilyl group as a solid content A photocatalyst aqueous coating solution having a solid content concentration of 25% by mass was prepared, and dried on an slate plate coated with acrylic coloring at 80 ° C. for 30 minutes to obtain a photocatalyst-coated body.
About the photocatalyst coating body of a magnitude | size of 50x100 mm obtained in this way, the weather resistance test was done as follows. The photocatalyst-coated body was put into a sunshine weatherometer (S-300C, manufactured by Suga Test Instruments) defined in JIS B7753. After 100 hours had elapsed, the test piece was taken out and the appearance change before and after the addition was observed. As a result, no change was observed in the appearance.

Experimental Example 6.
(Surface coating treatment of anatase-type titanium oxide particles)
Hydrophobized titanium oxide particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of anatase-type titanium oxide particles (average crystallite diameter: 10 nm).
(Silica particle surface coating treatment)
Hydrophobized silica particles were prepared by reacting 5 parts by weight of trialkoxysilane with 100 parts by weight of silica particles (average particle size 50 nm).
(Production of photocatalyst coating)
Solid content concentration containing 1.3 parts by mass of the hydrophobized titanium oxide particles, 8.7 parts by mass of the hydrophobized silica particles, and 90 parts by mass of a silicone emulsion having a methylphenylsilyl group as a solid content A photocatalyst-coated body was obtained by preparing a 25% by weight photocatalyst aqueous coating solution and drying it at 150 ° C. for 5 minutes on a substrate coated with acrylic coloring on a transparent slate plate.
About the photocatalyst coating body of a magnitude | size of 50x100 mm obtained in this way, the weather resistance test was done as follows. The photocatalyst-coated body was put into a sunshine weatherometer (S-300C, manufactured by Suga Test Instruments) defined in JIS B7753. After 100 hours had elapsed, the test piece was taken out and the appearance change before and after the addition was observed. As a result, no change was observed in the appearance.

Claims (17)

A photocatalyst-coated body provided with a photocatalyst layer on a substrate surface,
The photocatalyst layer comprises photocatalytic metal oxide particles, silica particles, and a dried resin emulsion,
The silica particles are coated or modified with a substance having a hydrophobic group,
The photocatalyst-coated body, wherein the concentration of the metal element of the photocatalytic metal oxide particles in the outermost layer of the photocatalyst layer is higher than that in the center of the layer. The photocatalyst coating according to claim 1, wherein the concentration of the metal element of the photocatalytic metal oxide particles in the photocatalyst layer shows a concentration gradient that gradually increases from the vicinity of the interface with the substrate to the outermost layer. body.   The photocatalyst-coated body according to claim 1 or 2, wherein the substance having a hydrophobic group is a silane having a hydrophobic group and / or a silicone having a hydrophobic group.   The photocatalyst coating body as described in any one of Claims 1-3 whose said photocatalytic metal oxide is a photocatalytic titanium oxide.   The photocatalyst-coated body according to any one of claims 1 to 4, wherein the photocatalyst layer has a thickness of more than 3 µm and less than 3 mm.   The photocatalyst coating body as described in any one of Claims 1-5 whose said photocatalyst layer is transparent.   The content of the dried product of the resin emulsion is 50% or more based on the total mass of the dried product of the resin emulsion, the photocatalytic metal oxide particles, and the silica particles. The photocatalyst coating body of description.   The photocatalyst coating body as described in any one of Claims 1-5 and 7 in which the said photocatalyst layer further contains a color pigment.   The photocatalyst coating body as described in any one of Claims 1-8 whose said resin emulsion is a silicone emulsion and / or a fluororesin emulsion.   The photocatalyst coating body as described in any one of Claims 1-9 whose average particle diameter of the said resin emulsion is larger than the average particle diameter of the said photocatalytic metal oxide particle and the said silica particle. Photocatalytic metal oxide particles,
Silica particles;
A resin emulsion;
Comprising a solvent,
The photocatalyst coating liquid, wherein the silica particles are coated or modified with a substance having a hydrophobic group.   The photocatalyst coating liquid according to claim 11, wherein the substance having a hydrophobic group is a silane having a hydrophobic group and / or a silicone having a hydrophobic group.   The photocatalyst coating liquid according to claim 11 or 12, wherein the photocatalytic metal oxide is photocatalytic titanium oxide.   The photocatalyst coating liquid as described in any one of Claims 11-13 in which the said photocatalyst layer further contains a color pigment. The solid content of the resin emulsion is 50% or more based on a total mass of the solid contents of the resin emulsion, the photocatalytic metal oxide particles, and the silica particles. The photocatalyst coating liquid described in 1.   The photocatalyst coating liquid as described in any one of Claims 11-15 whose said resin emulsion is a silicone emulsion and / or a fluororesin emulsion.   The photocatalyst coating liquid as described in any one of Claims 11-16 whose average particle diameter of the said resin emulsion is larger than the average particle diameter of the said photocatalytic metal oxide particle and the said silica particle.

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