JP5305231B2 - Photocatalyst paint - Google Patents

Description

  The present invention relates to a photocatalyst-coated body having a photocatalyst layer excellent in high weather resistance, harmful gas decomposability, light resistance, and various film performances, which is particularly suitable for applications such as exterior materials and interior materials such as buildings.

  In recent years, photocatalysts such as titanium oxide have been used in many applications such as exterior and interior materials for buildings. For exterior applications, by applying a photocatalyst to the substrate surface, it is possible to impart a decomposition function of harmful substances such as NOx and SOx using light energy. In addition, for interior applications, it is possible to add a function to decompose harmful substances such as VOCs using light energy.

When obtaining such a photocatalyst-coated body, an intermediate layer is provided between the base material serving as the base and the photocatalyst for the purpose of adhesion and / or suppression of deterioration of the base material surface due to the photocatalyst. The following are known as techniques for obtaining a photocatalyst-coated body coated with such a photocatalyst.

  A technique is known in which an intermediate layer such as a silicone-modified resin is provided between a base material serving as a base and a photocatalyst for the purpose of adhesion and / or suppression of deterioration of the base material surface by the photocatalyst. (For example, refer to Patent Document 1 (International Publication No. 97/00134 pamphlet)).

  In addition, an intermediate layer is provided between the base substrate and the photocatalyst, and an ultraviolet absorbing material such as an inorganic semiconductor, salicylic acid-based, benzophenone-based, benzotriazole-based, or cyanoacrylate-based organic material is blended in the intermediate layer. Further, techniques for suppressing deterioration of the substrate surface are also known (see, for example, Patent Document 2 (Japanese Patent Laid-Open No. 2006-116461) and Patent Document 3 (Japanese Patent Laid-Open No. 2008-272718)).

A technique for obtaining a photocatalyst by forming a coating film containing silica sol as a binder component of a photocatalyst layer and photocatalytic titanium dioxide on a substrate is also known (for example, Japanese Patent Application Laid-Open No. 11-169727). reference). In this technique, the amount of silica sol added is ₂₀ to 200 parts by weight with respect to titanium dioxide on the basis of SiO ₂ , and the content ratio of titanium dioxide is high. In addition, the particle size of silica sol is as small as 0.1 to 10 nm.

  In addition, a technique for adding a binder component such as hydrolyzable silicone to the photocatalyst for the purpose of enhancing the durability of the coated body is known. (See Patent Document 5 (Japanese Patent Laid-Open No. 2001-212510)), (See Patent Document 6 (Japanese Patent Laid-Open No. 2002-137322)).

WO97 / 00134 pamphlet JP 2006-116461 A JP 2008-272718 A JP 11-169727 A JP 2001-212510 A JP 2002-137322 A

  In order to obtain sufficient photocatalytic activity, it has been conventionally practiced to increase the amount of photocatalyst contained in the photocatalyst layer. However, when such a coating composition is used, the intermediate layer may be deteriorated by the photocatalyst. There was a concern about the occurrence of defects. Further, when the amount of the photocatalyst is reduced, the ultraviolet shielding effect in the photocatalyst layer is weakened, and there is a concern that the coating film and the underlying layer are deteriorated by ultraviolet light.

  In view of the above circumstances, an object of the present invention is to provide a photocatalyst-coated body that exhibits weather resistance and harmful gas decomposability while preventing erosion of the intermediate layer and the substrate.

  That is, the photocatalyst-coated body according to the present invention is a photocatalyst-coated body including a base material, an intermediate layer provided on the base material, and a photocatalyst layer, and the photocatalyst layer has an average particle size of less than 100 nm and excited. Photocatalyst particles having a wavelength of 380 nm or more are included, and the intermediate layer contains a weather resistant resin, an inorganic extender pigment or an inorganic white pigment having an average particle diameter of 100 nm or more, and a hydroxyphenyltriazine compound. It is a featured photocatalyst-coated body.

Photocatalyst-coated body A photocatalyst-coated body according to the present invention is a photocatalyst-coated body comprising a base material, an intermediate layer provided on the base material, and a photocatalyst layer, wherein the photocatalyst layer has an average particle size. Includes photocatalyst particles having an excitation wavelength of less than 100 nm and an excitation wavelength of 380 nm or more, and the intermediate layer contains a weather-resistant resin, an inorganic extender pigment or an inorganic white pigment having an average particle diameter of 100 nm or more, and a hydroxyphenyltriazine compound This is a photocatalyst-coated body characterized by the above.
That is, the photocatalyst-coated body according to the present invention has a hydroxyphenyl triazine compound that effectively absorbs ultraviolet light having a short wavelength of less than 380 nm and an average particle diameter of 100 nm that effectively reflects light and heat rays having a long wavelength of 380 nm or more. By containing the above inorganic extender pigment or inorganic white pigment and selecting a photocatalyst having an excitation wavelength of 380 nm or more as the photocatalyst particles in the photocatalyst layer, the photocatalyst probably reflects reflected light from the inorganic extender pigment or the inorganic white pigment. In addition to contributing to the function, it is possible to cut harmful UV rays of less than 380 nm that damage the intermediate layer and the base material, effectively exhibiting the decomposition function of the photocatalyst, and improving the weather resistance of the base material and the intermediate layer It becomes possible.
Here, the “average particle diameter” is calculated as a number average value obtained by measuring the lengths of arbitrary 100 particles entering 1 to 10 visual fields with a scanning electron microscope. When the inorganic extender pigment is rod-shaped, the average in the longitudinal direction is taken.

  In a preferred embodiment of the present invention, a hindered amine is contained. By doing so, the absorption performance of ultraviolet rays having a short wavelength of less than 380 nm by the hydroxyphenyltriazine compound is stabilized.

  In a preferred embodiment of the present invention, the weather resistant resin is a silicone-modified resin. By using the silicone-modified resin, the weather resistance of the intermediate layer is improved.

In a preferred embodiment of the present invention, the silicon content in the silicone-modified resin is 0.2% by mass or more and less than 16.5% by mass with respect to the solid content of the silicone-modified resin.
The silicon atom content is preferably 0.2% by mass or more and less than 16.5% by mass, and more preferably 6.5% by mass or more and less than 16.5% by mass with respect to the solid content of the silicone-modified resin. When the silicon atom content in the silicone-modified resin is 0.2% by mass or more, preferably 6.5% by mass or more, the weather resistance of the intermediate layer is lowered and the possibility of being eroded by the photocatalyst is reduced. can do. Moreover, generation | occurrence | production of the crack in an intermediate | middle layer resulting from lacking in flexibility can be suppressed because silicon atom content contained in silicone modified resin shall be less than 16.5 mass%.
Here, the silicon atom content in the silicone-modified resin can be measured by chemical analysis using an X-ray photoelectron spectrometer (XPS).

In a preferred embodiment of the present invention, the hydroxyphenyl triazine compound is contained in an amount of 0.1% by mass or more and less than 10% by mass with respect to the intermediate layer.
By setting it within this range, the absorption performance of ultraviolet rays having a short wavelength of less than 380 nm is sufficiently exhibited.

  The hydroxyphenyl triazine compound used in the present invention is a derivative of hydroxyphenyl triazine and / or hydroxyphenyl triazine having a basic skeleton represented by the following general formula (Chemical Formula 1), and a commercially available hydroxyphenyl triazine-based UV absorber is preferable. Can be used.

In a preferred embodiment of the present invention, the inorganic extender pigment or the inorganic white pigment is contained in an amount of 3% by mass or more and less than 70% by mass with respect to the intermediate layer.
By setting it within this range, light rays and heat rays having a long wavelength of 380 nm or more are effectively reflected.

In a preferred embodiment of the present invention, the inorganic extender pigment or the inorganic white pigment is a titanium-containing oxide.
Titanium-containing oxides such as titanium oxide and potassium titanate have high whiteness and effectively reflect light rays and heat rays having a long wavelength of 380 nm or more.

In a preferred embodiment of the present invention, the photocatalyst layer has air permeability.
By doing so, it becomes possible to make the reflected light from the inorganic extender pigment or the inorganic white pigment effectively contribute to the photocatalytic function.

In a preferred embodiment of the present invention, the content of the photocatalyst particles contained in the photocatalyst layer is more than 1% by mass and less than 15% by mass.
By setting it as the above range, it is possible to effectively suppress direct contact with the intermediate layer of the photocatalyst particles while effectively contributing the reflected light beam from the inorganic extender pigment or the inorganic white pigment to the photocatalytic function. Since it becomes difficult to erode, it can simultaneously exhibit excellent photocatalytic function and sufficient weather resistance under sunlight irradiation in temperate and subarctic regions.

In a preferred embodiment of the present invention, the content of the photocatalyst particles contained in the photocatalyst layer is more than 1% by mass and less than 5% by mass.
By making the above range, the direct contact with the intermediate layer of the photocatalyst particles can be minimized while effectively reflecting the reflected light from the inorganic extender pigment or the inorganic white pigment to the photocatalytic function. Since it is difficult to erode, it can simultaneously exhibit excellent photocatalytic function and sufficient weather resistance under tropical and subtropical sunlight irradiation.

In a preferred embodiment of the present invention, the photocatalyst layer contains inorganic oxide particles in addition to the photocatalyst particles.
By making the main component of the binder component other than the photocatalyst particles into a particulate inorganic oxide, sufficient air permeability can be secured in the photocatalyst layer, and reflected light from the inorganic extender pigment or inorganic white pigment can be effectively used by the photocatalyst function. It is possible to contribute.

In a preferred embodiment of the present invention, the photocatalyst layer is hydrolyzable as an optional component, with photocatalyst particles exceeding 1 part by mass and less than 15 parts by mass, inorganic oxide particles exceeding 75 parts by mass and less than 99 parts by mass. At least one selected from the group consisting of a polycondensation product of silicone and a polycondensation product of a hydrolyzate of an organometallic compound is used in an amount of 0 to 10 parts by mass, the photocatalyst particles, the inorganic oxide particles, and the optional It is made to contain so that the total amount of the component oxide conversion amount may be 100 mass parts.
By doing so, it is possible to simultaneously exhibit excellent photocatalytic function and sufficient weather resistance under sunlight irradiation in the temperate and subarctic regions, and it is possible to ensure sufficient air permeability in the photocatalyst layer, the inorganic extender pigment or The reflected light from the inorganic white pigment can be effectively contributed by the photocatalytic function.

In a preferred embodiment of the present invention, the photocatalyst layer is hydrolyzable as an optional component, with photocatalyst particles exceeding 1 part by mass and less than 5 parts by mass, inorganic oxide particles exceeding 85 parts by mass and less than 99 parts by mass. At least one selected from the group consisting of a polycondensation product of silicone and a polycondensation product of a hydrolyzate of an organometallic compound is used in an amount of 0 to 10 parts by mass, the photocatalyst particles, the inorganic oxide particles, and the optional It is made to contain so that the total amount of the oxide conversion amount of a component may be 100 mass parts.
By doing so, it is possible to simultaneously exhibit excellent photocatalytic function and sufficient weather resistance under sunlight irradiation in the tropical and subtropical regions, and also ensure sufficient air permeability in the photocatalyst layer. The reflected light can be effectively contributed by the photocatalytic function.

Photocatalyst particles having an average photocatalyst particle diameter of less than 100 nm and an excitation wavelength of 380 nm or more are included. 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.

Photocatalyst particles having an excitation wavelength of 380 nm or more include anatase-type titanium oxide, rutile-type titanium oxide, brookite-type titanium oxide, metal oxide particles such as ZnO, SrTiO ₃ , WO ₃ and Fe ₂ O ₃ , and the above metal oxide Visible light excitation type photocatalyst particles doped with metals such as platinum, gold, copper, etc. or ions thereof, visible light excitation type photocatalyst particles doped with nitrogen, sulfur, etc. into the above metal oxides, oxygen deficiency of the above metal oxides Visible-light-excited photocatalyst particles with an increased amount of light, visible-light-excited photocatalyst particles obtained by heterojunction of two or more of the above metal oxides, preferably titanium oxide particles, tungsten oxide particles, or any of them This is a visible light excitation type photocatalyst particle obtained by doping a metal oxide such as platinum, gold, copper or the like or ions thereof.

  According to a preferred embodiment of the present invention, the photocatalyst 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. 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, harmful gas decomposability, and various desired coating properties (transparency, coating strength, etc.) are efficiently exhibited.

  Furthermore, it is more preferable that the linear transmittance of the photocatalyst layer at a wavelength of 550 nm is secured to 90% or more, more preferably 95% or more. By doing so, it becomes possible to express without impairing the color and design of the groundwork. Moreover, even if it is coated on highly transparent glass or plastic, the transparency is not impaired.

  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. And / or a metal compound comprising the metal can be added to a photocatalyst coating solution applied on the intermediate layer to form a photocatalyst layer or a photocatalyst layer. This addition can be performed by any method such as a method in which the metal or metal compound is mixed and dissolved or dispersed in a coating solution, or a method in which the metal or metal compound is supported on a photocatalyst layer or photocatalyst particles.

  In the present invention, it is preferable that inorganic oxide particles are contained in the photocatalyst layer. 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 any kind of inorganic oxide particles can be used. Examples of such inorganic oxide particles include silica, alumina, zirconia, ceria, yttria, tin oxide, iron oxide, manganese oxide, nickel oxide, cobalt oxide, hafnia and other single oxide particles; and titanic acid Examples include particles of complex oxides such as barium, calcium silicate, aluminum borate, and potassium titanate, and silica particles are more preferable. These inorganic oxide particles are preferably in the form of an aqueous colloid using water as a dispersion medium; or an organosol dispersed in a hydrophilic solvent such as ethyl alcohol, isopropyl alcohol, or ethylene glycol, and particularly preferably. Colloidal silica.

  The inorganic oxide particles have an average particle diameter of more than 5 nm and not more than 20 nm, preferably not less than 10 nm and not more than 20 nm. 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, harmful gas decomposability, and various desired coating properties (transparency, coating strength, etc.) are efficiently exhibited, and in particular, a photocatalyst layer that is transparent and has good adhesion can be obtained. Not only can a film that is strong against sliding wear be obtained.

  In order to ensure air permeability, the photocatalyst layer of the present invention preferably does not substantially contain a hydrolyzable silicone condensation polymer, and more preferably does not contain it at all. Here, the hydrolyzable silicone is a general term for an organosiloxane having an alkoxy group and / or a partially hydrolyzed condensate thereof. The content of the hydrolyzable silicone polycondensate is 0 to 10 parts by mass with respect to 100 parts by mass of the total amount of photocatalyst particles, inorganic oxide particles, and hydrolyzable silicone polycondensate in terms of silica. Is preferably 5 parts by mass or less, and most preferably 0 part by mass. As the hydrolyzable silicone, a silicone compound having 2 to 4 functional silane as a monomer unit is often used, and for example, ethyl silicate, methyl silicate, alkyl group-containing silicone, phenyl group-containing silicone and the like can be suitably used.

  In order to ensure air permeability, the photocatalyst layer of the present invention preferably contains substantially no polycondensate of a hydrolyzate of an organometallic compound, and more preferably does not contain at all. Here, the organometallic compound is a metal alkoxide containing a metal element such as titanium, zirconium, or aluminum, a metal organic complex, or the like. The content of the polycondensation product of the hydrolyzate of the organic metal is 0 parts by mass or more and 10 parts by mass with respect to 100 parts by mass in total of the photocatalyst particles, inorganic oxide particles, and hydrolyzable silicone in terms of metal oxide Is preferably 5 parts by mass or less, and most preferably 0 part by mass.

  The photocatalyst layer of the present invention comprises at least one selected from the group consisting of a hydrolyzable silicone polycondensate and an organometallic compound hydrolyzate as an optional component. The content of the optional component is preferably 0 parts by mass or more and less than 10 parts by mass with respect to 100 parts by mass of the total amount of the photocatalyst particles, the inorganic oxide particles, and the oxide conversion amount of these optional components, Preferably it is 5 mass parts or less, Most preferably, it is 0 mass part.

  The photocatalyst layer preferably has a thickness of 0.1 μm to 5.0 μm, more preferably 0.5 μm to 3.0 μm, and most preferably 1.0 μm to 2.0 μm. is there. Within such a range, the photocatalyst particles having a lower content ratio than the inorganic oxide particles can be increased in the film thickness direction, so that the harmful gas decomposability is improved. Furthermore, excellent characteristics can be obtained in terms of transparency.

  The contents described in the above-mentioned sections “photocatalyst layer” and “photocatalyst-coated body” can be arbitrarily combined.

Photocatalyst layer manufacturing method The photocatalyst coating body of this invention can be easily manufactured by apply | coating a photocatalyst coating liquid on the base material which has an intermediate | middle layer. 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.

The photocatalyst coating liquid basically contains photocatalyst particles having an average particle diameter of less than 100 nm and an excitation wavelength of 380 nm or more, and a solvent.
As the “photocatalyst particles”, those described in the above “photocatalyst layer” and “photocatalyst-coated body” can be suitably used.
Further, “inorganic oxide particles”, “hydrolyzable silicone”, and “organometallic compound” may be included, but those described in the above-mentioned “photocatalyst layer” and “photocatalyst-coated body” can be preferably used.

  As a solvent for the photocatalyst coating liquid, any solvent that can appropriately disperse the above components can be used, and water and / or an organic solvent may be used. Moreover, the solid content concentration of the photocatalyst coating liquid is not particularly limited, but it is preferably 1 to 10% by mass because it is easy to apply. The components in the photocatalyst coating composition 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.

  The photocatalyst coating liquid may contain a surfactant as an optional component. The surfactant used in the present invention may be contained in the photocatalyst layer in an amount of 0 to less than 10 parts by mass with respect to 100 parts by mass of the total amount of photocatalyst particles, inorganic oxide particles, and hydrolyzable silicone, Preferably they are 0 mass part or more and 8 mass parts or less, More preferably, they are 0 or more and 6 mass parts or less. One of the effects of the surfactant is leveling to the substrate, and the amount of the surfactant may be appropriately determined within the above-mentioned range depending on the combination of the coating liquid and the substrate, and the lower limit at that time is 0 It may be 1 part by mass. This surfactant is an effective component for improving the wettability of the photocatalyst coating solution, but in the photocatalyst layer formed after coating, it is an inevitable impurity that no longer contributes to the effect of the photocatalyst-coated body of the present invention. Equivalent to. Therefore, it may be used within the above-mentioned content range depending on the wettability required for the photocatalyst coating liquid, and if the wettability is not a problem, the surfactant may be contained substantially or not at all. The surfactant to be used can be appropriately selected in consideration of the dispersion stability of the photocatalyst and inorganic oxide particles, and wettability when applied on the intermediate layer, but a nonionic surfactant is preferable, More preferably, an ether type nonionic surfactant, an ester type nonionic surfactant, a polyalkylene glycol nonionic surfactant, a fluorine-based nonionic surfactant, or a silicon-based nonionic surfactant is used. Can be mentioned.

As an essential component of the intermediate layer , a weather resistant resin, an inorganic extender pigment or an inorganic white pigment having an average particle diameter of 100 nm or more, and a hydroxyphenyltriazine compound are included.

  The weather resistant resin is not particularly limited as long as it has good compatibility with the ultraviolet absorber, has adhesion to the base material, and adhesion to the photocatalyst, and can suppress deterioration of the intermediate layer surface due to the photocatalyst. Silicone-modified resins such as silicone-modified acrylic resins, silicone-modified epoxy resins, silicone-modified urethane resins, and silicone-modified polyesters containing polysiloxane in the resin are suitable. When applied to exterior building materials, silicone-modified acrylic resins are more suitable from the viewpoint of weather resistance. In the silicone-modified acrylic resin, it is more preferable to use a mixture of two liquids of a silicone-modified acrylic resin having a carboxyl group and a silicone resin having an epoxy group from the viewpoint of improving the strength of the coating film.

As the inorganic extender pigment of the present invention, extender pigments having an average particle diameter of 100 nm or more can be used. For example, titanium oxide whisker, calcium carbonate whisker, aluminum borate whisker, potassium titanate whisker, mica, talc and the like can be suitably used. .
As the inorganic white pigment of the present invention, an inorganic white pigment having an average particle diameter of 100 nm or more can be used. For example, titanium oxide white, zinc oxide white, or the like can be used.
In addition, this average particle diameter is calculated as a number average value obtained by measuring the length of any 100 particles that fall within 1 to 10 fields of view with a scanning electron microscope. When the inorganic extender pigment is rod-shaped, the average in the longitudinal direction is taken.

In the present invention, other fillers such as inorganic coloring pigments other than white, organic coloring pigments, anti-algae agents, and silica particles having an average particle size of 100 nm or less may be added.
The inorganic coloring pigments other than white are not particularly limited, and for example, iron oxide, carbon black, spinel green, bengara, cobalt aluminate, ultramarine blue and the like can be suitably used.
As organic coloring pigments, phthalocyanine, benzimidazolone, isoindolinone, azo, anthraquinone, quinophthalone, anthrapyridinine, quinacridone, toluidine, pyrathrone, perylene, etc. are preferably used. it can.
As the anti-algae, organic anti-fungal agents having good compatibility with the resin component of the intermediate layer can be suitably used. For example, organic nitrogen sulfur compounds, pyrithion compounds, organic iodine compounds, triazine compounds, isothiazolines A compound, an imidazole compound, a pyridine compound, a nitrile compound, a thiocarbamate compound, a thiazole compound, a disulfide compound, or the like can be suitably used.

  Although the dry film thickness of an intermediate | middle layer is not specifically limited, Preferably they are 1 micrometer-50 micrometers, More preferably, they are 1 micrometer-10 micrometers. If the thickness is less than 1 μm, the effect of suppressing degradation of the intermediate layer and the substrate by the photocatalyst may be inferior. When it is thicker than 50 μm, although it depends on the type of the intermediate layer, there is a possibility that fine cracks may occur after drying.

  The contents described in the above-mentioned “intermediate layer”, “photocatalyst-coated body”, and “photocatalyst layer” can be arbitrarily combined.

Intermediate Layer Manufacturing Method The intermediate layer can be easily manufactured by applying an intermediate layer coating solution onto the substrate. As a method for coating the intermediate 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.

  The intermediate layer coating liquid basically contains a weather resistant resin or a precursor before polymerization thereof, an inorganic extender pigment or an inorganic white pigment having an average particle diameter of 100 nm or more, and a hydroxyphenyltriazine compound.

  As the “weather-resistant resin” and “inorganic extender pigment or inorganic white pigment having an average particle diameter of 100 nm or more”, those described in the above “photocatalyst layer” and “photocatalyst-coated body” can be preferably used.

  As the solvent for the intermediate layer coating liquid, any solvent that can appropriately disperse the above components can be used, and water and / or an organic solvent may be used. The solid content concentration of the intermediate layer coating solution of the present invention is not particularly limited, but it is preferably 10 to 20% by mass in terms of easy application. In addition, the analysis of the structural component in an intermediate | middle layer coating liquid can be evaluated by infrared spectroscopy about a resin component.

  In addition to the above, the intermediate layer coating liquid contains “inorganic colored pigments other than white”, “organic colored pigments”, “algaeproofing agents”, and “fillers such as silica particles having an average particle size of 100 nm or less”. However, those described in the above-mentioned “intermediate layer” can also be suitably used.

  In addition to the above, the intermediate layer coating solution may contain paint additives such as pigment dispersants, antifoaming agents, and antioxidants, and other components usually included in paints. Further, a matting agent such as silica fine particles may be included.

Base Material The base material used in the present invention may be any material, regardless of inorganic material or organic material, as long as the intermediate layer can be formed thereon, and the shape 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, exterior and painting of guard rails, interior and painting of tunnels, insulators, solar battery 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.

<Preparation of painted body sample>
Examples 1 to 7 and Comparative Examples 1 to 4 were produced as follows.
Example 1:
Base material: Glass base material Intermediate layer: Silicone-modified acrylic resin dispersion having a silicon atom content of 10% by weight based on the solid content of the silicone-modified resin, and 1% by weight of hydroxyphenyltriazine based on the solid content of the dispersion Spray coat the intermediate layer coating solution in which the compound, 1% by weight of hindered amine, and 30% by weight of the titanium oxide white pigment with an average particle diameter of 200 nm based on the solid content of the dispersion, and dry at 120 ° C. An intermediate layer having a thickness of 10 μm was formed.
Photocatalyst layer: anatase-type titanium oxide aqueous dispersion (average particle size: about 50 nm, basic), water-dispersed colloidal silica (average particle size: about 30 nm, basic), polyether-modified silicone surfactant, Were mixed to obtain a photocatalyst coating solution. The total solid concentration of the photocatalyst and the inorganic oxide in the photocatalyst coating solution was 5.5% by mass. The obtained photocatalyst coating liquid was spray-coated on the intermediate layer-coated body heated in advance and dried at 120 ° C. Titanium oxide in the obtained photocatalyst layer was 2 parts by mass, silica was 98 parts by mass, and the surfactant was 6 parts by mass. The film thickness of the photocatalyst layer was 0.5 μm.

Example 2: In Example 1 above, the amount of titanium oxide in the photocatalyst layer was 15 parts by mass, and the silica was 85 parts by mass.
Example 3: Instead of “mixing 30% by mass of titanium oxide white pigment with an average particle diameter of 200 nm” in the intermediate layer in Example 1 above, “15% by mass of average diameter of 100 nm and average length of 20 μm” Of potassium titanate whisker and 25% by weight of titanium oxide white pigment having an average particle diameter of 200 nm ”.
Example 4: In Example 3 above, the amount of titanium oxide in the photocatalyst layer was 15 parts by mass, and silica was 85 parts by mass.
Example 5: Instead of “compounding 30% by mass of titanium oxide white pigment with an average particle diameter of 200 nm” in the intermediate layer in Example 1, “10% by mass of talc with an average particle diameter of 2.5 μm” "
Example 6: In Example 5 above, the amount of titanium oxide in the photocatalyst layer was 15 parts by mass, and the silica was 85 parts by mass.
Example 7 In the above Example 1, the amount of titanium oxide in the photocatalyst layer was 4 parts by mass, and the silica was 96 parts by mass.

Comparative Example 1: In Example 1 above, tin oxide (average particle size: about 10 nm) was used instead of anatase-type titanium oxide (average particle size: about 50 nm) for the photocatalyst particles in the photocatalyst layer.
Comparative Example 2: In the above Example 2, “anatase type titanium oxide (average particle size: about 50 nm)” was used in place of “titanium oxide white pigment having an average particle size of 200 nm” in the intermediate layer.
Comparative Example 3: In Example 2 above, neither a hydroxyphenyl triazine compound nor a hindered amine was added to the intermediate layer.
Comparative Example 4: Instead of adding “the intermediate layer hydroxyphenyltriazine compound is 0.07 parts by mass and hindered amine is 1% by mass” in Example 1, “1 part by mass of benzophenone compound” was added.

About the obtained sample, the photocatalytic decomposition activity by BLB of 3 mW / cm ² was evaluated, and the degree of deterioration of the intermediate layer when it was put into a sunshine weather meter defined in JIS B7753 for 300 hours. The results are shown in Table 1.

  For Examples 1, 3, 5, and 7, further, outdoor exposure was performed for 6 months at an angle of 20 ° from the horizontal toward the south surface in Miyakojima using an exposure stand defined in JIS K5600-7-6. The appearance change was evaluated. The results are shown in Table 2.

Claims (13)

A photocatalyst-coated body comprising a base material, an intermediate layer provided on the base material, and a photocatalyst layer,
The photocatalytic layer has a linear transmittance of 90% or more for light having a wavelength of 550 nm,
The photocatalyst layer contains photocatalyst particles having an average particle diameter of less than 100 nm and an excitation wavelength of 380 nm or more,
The intermediate layer contains a weather-resistant resin, an inorganic extender pigment or inorganic white pigment having an average particle size of 100 nm or more, and a hydroxyphenyltriazine compound.
  The photocatalyst-coated body according to claim 1, wherein the intermediate layer further contains a hindered amine.   The photocatalyst-coated body according to claim 1 or 2, wherein the weather-resistant resin is a silicone-modified resin.   The photocatalyst-coated body according to claim 3, wherein the silicon content in the silicone-modified resin is 0.2% by mass or more and less than 16.5% by mass with respect to the solid content of the silicone-modified resin.   The photocatalyst-coated body according to any one of claims 1 to 4, wherein the hydroxyphenyltriazine compound is contained in an amount of 0.1% by mass or more and less than 10% by mass with respect to the intermediate layer.   The photocatalyst-coated body according to any one of claims 1 to 5, wherein the inorganic extender pigment or the inorganic white pigment is contained in an amount of 3% by mass or more and less than 70% by mass with respect to the intermediate layer.   The photocatalyst-coated body according to any one of claims 1 to 6, wherein the inorganic extender pigment or the inorganic white pigment is a titanium-containing oxide.   The said photocatalyst layer has air permeability, The photocatalyst coating body of any one of Claims 1-7 characterized by the above-mentioned.   Content of the said photocatalyst particle contained in the said photocatalyst layer exceeds 1 mass%, and is less than 15 mass%, The photocatalyst coating body of any one of Claims 1-8 characterized by the above-mentioned.   The photocatalyst-coated body according to any one of claims 1 to 9, wherein the content of the photocatalyst particles contained in the photocatalyst layer is more than 1% by mass and less than 5% by mass.   The photocatalyst-coated body according to any one of claims 1 to 10, wherein the photocatalyst layer contains inorganic oxide particles in addition to the photocatalyst particles. The photocatalytic layer is
The photocatalyst particles of more than 1 part by weight and less than 15 parts by weight;
More than 75 parts by weight and less than 99 parts by weight of the inorganic oxide particles;
As an optional component, at least one selected from the group consisting of a hydrolyzable silicone polycondensate and an organometallic hydrolyzate polycondensate is 0 part by mass or more and less than 10 parts by mass, the photocatalyst particles, the inorganic 12. The photocatalyst-coated body according to claim 11, comprising a total amount of oxide particles and an oxide-converted amount of the optional component of 100 parts by mass. The photocatalytic layer is
The photocatalyst particles of more than 1 part by weight and less than 5 parts by weight;
Greater than 85 parts by weight and less than 99 parts by weight of the inorganic oxide particles;
As an optional component, at least one selected from the group consisting of a hydrolyzable silicone polycondensate and an organometallic hydrolyzate polycondensate is 0 part by mass or more and less than 10 parts by mass, the photocatalyst particles, the inorganic 12. The photocatalyst-coated body according to claim 11, comprising a total amount of oxide particles and an oxide-converted amount of the optional component of 100 parts by mass.