JP2011012486A - Rain gutter and coating liquid for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rain gutter and a coating liquid for the rain gutter obtaining a high degree of photocatalyst decomposition activity even in the case of coating with a thick film exceeding 2 μm to suppress the deterioration of an enamel coated surface or a clear coated surface.SOLUTION: An external wall building material includes a photocatalyst layer on the surface of a base material. The photocatalyst layer is obtained by applying a photocatalyst coating liquid and then drying it. The photocatalyst coating liquid includes photocatalyst metal oxide particles, hydrophilic silica particles and curable silicone emulsion. The hydrophilic silica particles are partially coated or denatured with a substance having a hydrophobic group.

Description

The present invention relates to a rain gutter having a photocatalytic function such as decomposability of harmful gas and self-cleaning property by rain and water washing.
Alternatively, the present invention relates to a coating liquid for rain gutter that can impart a photocatalytic function such as harmful gas decomposability and self-cleaning property by rain / water washing to a member constituting a gutter and a composite material by forming a coating layer.

In recent years, photocatalysts such as titanium oxide have been used in many applications such as members and composite materials constituting buildings of buildings.
For outdoor use, by applying a photocatalyst to the surface of the base material, it is possible to impart a function of decomposing harmful substances such as NOx and SOx using light energy. Further, if the surface of the layer is made at least hydrophilic when irradiated with light, it is possible to provide a self-cleaning function in which attached dirt is washed away by rain.

In the case of components, composites, etc. that constitute a building of a building, the surface of the base material to which the photocatalytic function is to be added is enameled or clear painted on the enamel to give design properties. There are many cases.
If an attempt is made to directly form a photocatalyst layer there, the enameled and clear painted surfaces are mainly composed of organic matter, and in the long term, the painted surface will deteriorate due to photocatalyst particles present at the interface between the photocatalyst layer and the painted surface. Cause problems.

For this reason, conventionally, a barrier layer containing a large amount of inorganic components has been formed between the enamel-coated surface, the clear-coated surface, and the photocatalyst layer (Japanese Patent Laid-Open No. 2007-167718).
However, when the barrier layer is formed, not only the cost is increased, but also man-hours are required and the photocatalytic function cannot be easily provided.

  Therefore, the photocatalytic function is exhibited while suppressing the deterioration of the enameled surface or the clear painted surface, more preferably, there is no off-flavor or environmental pollution during application, and most preferably the deterioration of the substrate surface due to ultraviolet rays is suppressed. There is a need for rain gutters or gutter coating liquids that are applied directly to the material to form a photocatalytic functional layer.

  As such a photocatalyst coating composition that directly exerts a photocatalytic function on one substrate, the content of silane-modified photocatalyst particles and alkoxy groups and / or hydroxyl groups bonded to silicon atoms is 7 to 20 mmol. An aqueous organic / inorganic composite composition comprising colloidal silica of / g and polymer emulsion particles having an alkoxy group bonded to a silicon atom and / or a hydroxyl group content of 1 to 20 mmol / g is known. (Japanese Unexamined Patent Application Publication No. 2008-222887).

JP 2007-167718 A JP 2008-2222887 A Patent 3985164 JP 2004-51644 A

However, in Japanese Patent Application Laid-Open No. 2008-222887, a high photocatalytic degradation activity cannot be obtained when a thick film exceeding 2 μm is coated so as to suppress the ultraviolet deterioration of the enamel coating surface or the clear coating surface.
Therefore, in the present invention, in view of the above circumstances, a rain gutter capable of obtaining a high photocatalytic degradation activity even when coating with a thick film exceeding 2 μm so as to suppress deterioration of the enamel coating surface or the clear coating surface, and The object is to provide a coating solution for rain gutters.

  That is, a rain gutter having a photocatalyst layer on a substrate surface, the photocatalyst layer is obtained by applying a photocatalyst coating liquid and then drying, and the photocatalyst coating liquid comprises photocatalytic metal oxide particles, It is a rain gutter characterized by comprising a hydrophilic silica particle and a curable silicone emulsion, wherein the hydrophilic silica particle is partially coated or modified with a substance having a hydrophobic group.

  The raindrop coating liquid according to the present invention comprises photocatalytic metal oxide particles, hydrophilic silica particles, curable silicone emulsion, and water, and the hydrophilic silica particles have a hydrophobic group. A coating solution for rain gutter characterized in that it is partially coated or modified with a substance.

The rain gutter according to the present invention is a rain gutter having a photocatalyst layer on the surface of a substrate, and the photocatalyst layer is obtained by applying a photocatalyst coating liquid and then drying the photocatalyst coating liquid. A rain comprising metal oxide particles, hydrophilic silica particles, and a curable silicone emulsion, wherein the hydrophilic silica particles are partially coated or modified with a substance having a hydrophobic group. It is a spear.
By adopting such a configuration, a rain gutter capable of obtaining a high degree of photocatalytic degradation activity even when coating with a thick film exceeding 2 μm so as to suppress deterioration of the enamel coated surface or the clear painted surface is provided. It becomes possible.
When the photocatalytic coating liquid is applied to the substrate and dried, the photocatalytic metal oxide particles and hydrophilic silica particles have an affinity for water and move to the surface when water diffuses and evaporates on the surface. It's easy to do. On the other hand, since photocatalytic metal oxide particles and hydrophilic silica particles have an affinity for water, the particles are likely to aggregate with each other, and this is particularly noticeable for silica particles having an excellent affinity for water.
In the present invention, silica particles are previously partially coated or modified with a substance having a hydrophobic group while maintaining hydrophilicity. By doing so, it can hold | maintain the state which a silica particle tends to move upwards at the time of drying, suppressing the aggregation of a silica particle effectively.
By using the above silica particles, it is possible to effectively avoid a state where the silica particles block the gap between the silicone emulsions and prevent the photocatalytic metal oxide particles from moving upward. You can concentrate on concentration.
With the above action, it is possible to provide a rain gutter capable of obtaining a high degree of photocatalytic decomposition activity even in a film having a long upward movement process, such as a thick film exceeding 2 μm.

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.
By doing so, it becomes easy to control the form of coating and modification on the silica surface.

  Further preferably, the photocatalytic metal oxide particles may be photocatalytic metal oxide particles that are not subjected to a treatment for reducing activity such as a silane modification treatment, a silicone modification treatment, a silane coating treatment, and a silicone coating treatment. . Nevertheless, according to the above action, the photocatalytic metal oxide particles can be concentrated on the surface at a high concentration, and a higher photocatalytic decomposition activity can be obtained without reducing the activity per photocatalytic metal oxide particle.

  However, as the photocatalytic metal oxide particles, photocatalytic metal oxide particles having a particle surface energy reduced by silane modification treatment, silicone modification treatment, silane coating treatment, silicone coating treatment, or the like may be used. By doing so, the photocatalytic metal oxide particles also form some agglomerated particles depending on the properties of the particles, but this can be effectively suppressed and the photocatalytic metal oxide particles can be concentrated at a higher concentration on the surface. There can be sex.

According to a preferred embodiment of the present invention, the hydrophilic silica particles have a total amount of hydroxyl groups and alkoxy groups bonded to silicon atoms of less than 6 mmol / g.
In this way, the silica particles can be easily moved upward at the time of drying while effectively suppressing the aggregation of the silica particles, so that the silica particles easily move upward, such as a thick film exceeding 2 μm, Even in a film having a long upward movement stroke, it becomes easier to provide a rain gutter capable of obtaining a high photocatalytic decomposition activity.

According to a preferred embodiment of the present invention, the curable silicone emulsion is 80% or more, preferably 85% or more, based on the total mass of the curable silicone emulsion, the photocatalytic metal oxide particles, and the hydrophilic silica particles. More preferably, it should be 90% or more. Here, the mass of the curable silicone emulsion is the mass of the solid content of the emulsion, and is determined by a constant weight value obtained by drying at 105 ° C.
By setting it to 80% or more, a high photocatalytic decomposition activity can be obtained even in a film having a long upward movement process, such as a thick film exceeding 2 μm, and a transparent photocatalytic layer can be formed when no colorant is added. It can be formed.
Furthermore, by making it 90% or more, it is possible to obtain a high photocatalytic decomposition activity even in a film having a long upward movement process, such as a thick film exceeding 5 μm, and a transparent photocatalyst when no colorant is added. A layer can be formed.

According to a preferred embodiment of the present invention, the film thickness of the photocatalyst layer is more than 2 μm and less than 20 μm, preferably more than 5 μm and less than 20 μm.
By doing so, the influence of the ultraviolet-ray to a base material can be lowered | hung and degradation of the base material by an ultraviolet-ray can be suppressed effectively.

According to a preferred embodiment of the present invention, the average particle size of the curable silicone emulsion is larger than the average particle size of the photocatalytic metal oxide particles and the hydrophilic silica particles.
By doing so, the upward movement of the photocatalytic metal oxide particles and the hydrophilic silica particles becomes remarkable.
Accordingly, the silica particles are easily moved upward without being bound by the silicone emulsion, and even in a film having a long upward movement process such as a thick film exceeding 2 μm, it is possible to obtain a high photocatalytic decomposition activity. Is easier to provide.

According to a preferred embodiment of the present invention, the photocatalyst layer is transparent.
By doing so, when the base material is enamel coating or clear coating, high photocatalytic degradation activity can be obtained even in a film having a long upward movement process, such as a thick film exceeding 2 μm, while effectively utilizing its design properties. It is easier to provide a possible rain gutter.

  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 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, the photocatalytic metal oxide particles include anatase type titanium oxide, rutile type titanium oxide, brookite type titanium oxide, tin oxide, zinc oxide, strontium titanate, tungsten oxide and cerium oxide. Particles of various metal oxides, particles obtained by combining a plurality of these particles, particles obtained by combining or doping these particles with a metal such as copper, platinum, iron, palladium, silver, and gold, and the surface of these particles. Particles partially coated and modified 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, harmful gas decomposability, and various desired coating properties (transparency, coating strength, etc.) are efficiently exhibited.

  According to a preferred embodiment of the present invention, the photocatalyst particles preferably have an average crystallite diameter 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 photocatalyst particles is a dry mass (solid content mass), with respect to a total mass of the curable silicone emulsion, the photocatalytic metal oxide particles, and the hydrophilic 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. By making it within the above range, it is possible to effectively exhibit the decomposition function of the photocatalyst and to improve the weather resistance of the base material and the intermediate layer to such an extent that it can withstand long-term use in the tropics and the like. It is also possible to suppress deterioration of the base material and the intermediate layer due to. That is, it is possible to simultaneously exhibit an ultraviolet absorption function in the photocatalyst layer and an excellent photocatalyst function under sunlight irradiation in the temperate and subarctic regions and sufficient weather resistance.

According to a preferred embodiment of the present invention, the hydrophilic silica particles preferably have an average particle size of more than 10 nm and 200 nm or less, more preferably more than 20 nm and 100 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).
By exceeding 10 nm and not more than 200 nm, more preferably exceeding 20 nm and not more than 100 nm, silica particles can easily move upward in the gaps of the curable silicone emulsion.

  According to a preferred embodiment of the present invention, the hydrophilic silica particles have a degree of hydrophilicity in which the total amount of hydroxyl groups and alkoxy groups bonded to silicon atoms in the hydrophilic silica particles is preferably less than 6 mmol / g, more preferably. Is about 1 mmol / g or more and less than 6 mmol / g.

As the substance having a hydrophobic group that partially coats or modifies the hydrophilic silica particles, for example, 1-3 functional silanes, silicones, and the like can be suitably used.
The amount of the substance used for the coating or modification treatment in the hydrophilic silica particles made of the substance having a hydrophobic group is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass with respect to the amount of silica. is there.

  Examples of the silane having a hydrophobic group used in the present invention include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrisilane. Methoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, Vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltrie Xysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxy Silane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanate pro Rutriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl Triethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloyloxypropyltri-n-propoxysilane, 3- (meth) acryloyloxy Trialkoxysilanes such as propyltriisopropoxysilane, 3-ureidopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, and diethyl Rudiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n -Pentyldimethoxysilane, 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) acryloyloxypropylmethyl Dialkoxysilane such as dimethoxysilane; trimethylmethoxysilane, monoalkoxysilane such as trimethyl silane, and the like. Moreover, these can be used individually or in mixture of 2 or more types.

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

The curable silicone emulsion refers to a silicone emulsion that, when applied to a substrate and dried, causes a curing polymerization reaction due to a functional group present in the silicone emulsion, thereby forming a cured film.
Here, a hydrolysis / condensation reaction, a photopolymerization reaction, or the like can be suitably used for the curing reaction.
When the curing reaction is a hydrolysis / condensation reaction, a curable silicone emulsion having an alkoxide group as a functional group and generating a siloxane bond by the hydrolysis / condensation reaction can be suitably used.

In the curable silicone emulsion, in addition to the functional group that causes the curing reaction, an organic cross-linked portion by emulsion polymerization is present.
As the organic crosslinking part, a crosslinking part produced by radical polymerization such as an ethylene crosslinking part in which a vinyl group and a vinyl group are polymerized can be suitably used. As long as it is a crosslinked part produced by radical polymerization, it is not particularly limited to a hydrocarbon group, and a combination of various modifying groups can be suitably used.

  In the curable silicone emulsion, an organic group bonded to a silicon atom may be present in addition to the functional group causing the curing reaction and the organic cross-linking portion. Here, examples of the organic group include hydrocarbon groups such as an alkyl group, a phenyl group, and a cycloalkyl group, and organic groups in which a part of the hydrogen is substituted with a modifying group. Here, as the modifying group, an amino group, a carboxyl group, a mercapto group, an acrylic group, an epoxy group, or the like can be suitably used.

  Next, the surfactant used as an emulsifier for the emulsion will be described. As the surfactant, conventionally known nonionic, cationic, and anionic surfactants and reactive emulsifiers containing functional groups capable of radical polymerization can be applied. Furthermore, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene carboxylic acid ester, sorbitan ester, polyoxyethylene sorbitan ester, and cations such as alkyltrimethylammonium chloride and alkylbenzylammonium chloride Surfactants, alkyl or alkyl allyl sulfates, anionic surfactants such as alkyl or alkyl allyl sulfonates, dialkyl sulphosuccinates, zwitterionic surfactants such as amino acid types and betaine types, Radical-polymerizable (meth) acrylate containing a hydrophilic group such as sulfonate, polyoxyethylene chain, quaternary ammonium salt in the molecule described in JP-A-8-27347 DOO, can indicate styrene, various reactive surfactants containing derivatives such as maleic acid ester compound.

  These surfactants may be used alone or in combination of two or more. The surfactant is preferably used in an amount of 0.5 to 15% by weight, particularly 1 to 10% by weight, based on the resin solid content in the emulsion.

  In the present invention, the photocatalyst layer may contain inorganic oxide particles other than hydrophilic 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 any kind of 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. These metals and / or metal compounds comprising these metals may be added. 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.

  You may mix | blend a ultraviolet absorber in a photocatalyst layer. 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 hydrophilicity expression, but for example, 0.001 to 10% by mass in the photocatalyst layer, preferably Is preferably contained in an amount of 0.01 to 5% by mass.

  Preferred examples of the ultraviolet absorber that can be used 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 Condensate with polyethylene glycol (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′-octoxyphe) ) 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 (Otsuka Chemical) Product name: RUVA-93), 2- (2′-hydroxy-5′-methacryloxyethyl-3-tert-butylphenyl) -2H Benzotriazole, 2- (2′-hydroxy-5′-methacrylyloxypropyl-3-tert-butylphenyl) -5-chloro-2H-benzotriazole, 3-methacryloyl-2-hydroxypropyl-3- [3 ′ Polymerizable benzotriazole ultraviolet absorbers such as-(2 "-benzotriazolyl) -4-hydroxy-5-tert-butyl] phenylpropionate (manufactured by Ciba-Geigy Japan, product name: CGL-104) And 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 Nippon Ciba-Geigy Corp.), TINUVIN-328 (product name, manufactured by Ciba-Geigy Corp. Japan), INUVIN-928 (product name, manufactured by Nihon Ciba-Geigy Corporation), and the like.

  Further, in the photocatalyst layer of the present invention, those further containing a hindered amine-based and / or hindered phenol-based light stabilizer, the photocatalyst layer of the present invention has excellent weather resistance due to a synergistic effect with the ultraviolet absorber. In view of light resistance, it is preferable.

  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 doing so, the absorption performance of ultraviolet rays having a short wavelength of less than 380 nm by the photocatalyst layer is stabilized.

The content of the light stabilizer in the photocatalyst layer of the present invention is not limited as long as the weather resistance can be improved without inhibiting the photocatalytic activity and / or the expression of hydrophilicity. -10% by mass, preferably 0.01-5% by mass.
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 Nippon Ciba-Geigy Corp.), 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.

As an optional component, the photocatalyst coating liquid may contain a surfactant in the coating liquid in addition to the emulsion emulsifier.
In a preferred embodiment of the present invention, the surfactant is preferably 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 photocatalyst 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 sulfosuccinate. Sodium acid, 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-ethylhexyl alkyl sulfate sodium salt, acylmethyl taurate sodium , 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 Anionic surfactant such as sodium salt; 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 Xylethylene 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, alkylalkylol Lauric acid diethanolamide, oleic acid diethanolamide, oxyethylene dodecylamine, polyoxyethylene dodecylamine, polyoxyethylene alkylamine, polyoxyethylene octadecylamine, polyoxyethylene alkylpropylenediamine, polyoxyethyleneoxypropylene block polymer, Nonionic surfactants such as polyoxyethylene stearate; amphoteric surfactants such as dimethylalkylbetaine, alkylglycine, amidebetaine, imidazoline, octadecyldimethylbenzylammonium chloride, alkyldimethylbenzylammonium chloride, tetradecylmethylbenzylammonium chloride, Dioleyldimethylammonium chloride, 1-hydroxyethyl-2- Rukiruimidazoline quaternary salt, alkylisoquinolinium bromide, polymeric amine, octadecyltrimethylammonium chloride, alkyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, alkylimidazoline quaternary salt, dialkyl And cationic surfactants such as dimethylammonium chloride, octadecylamine acetate, tetradecylamine acetate, alkylpropylenediamine acetate, and didecyldimethylammonium chloride.

  An organic antifungal agent may be blended in the photocatalyst layer. Examples include organic nitrogen sulfur compounds, pyrithione compounds, organic iodine compounds, triazine compounds, isothiazoline compounds, imidazole compounds, pyridine compounds, nitrile compounds, thiocarbamate compounds, thiazole compounds, and organic iodine. Compounds and disulfide compounds may be mentioned and 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 coating solution for rain gutters according to the present invention comprises photocatalytic metal oxide particles, hydrophilic silica particles, curable silicone emulsion, and water, and the hydrophilic silica particles are hydrophobic. A coating solution for rain gutter which is partially coated or modified with a group-containing substance.
With such a configuration, a coating solution for rain gutter capable of obtaining a high photocatalytic decomposition activity even when coating with a thick film exceeding 2 μm so as to suppress deterioration of the enamel painted surface or the clear painted surface. Can be provided.
When the coating solution for rain gutter is applied to the substrate and dried, the photocatalytic metal oxide particles and the hydrophilic silica particles have an affinity for water. Easy to move to. On the other hand, since photocatalytic metal oxide particles and hydrophilic silica particles have an affinity for water, the particles are likely to aggregate with each other, and this is particularly noticeable for silica particles having an excellent affinity for water.
In the present invention, silica particles are previously partially coated or modified with a substance having a hydrophobic group while maintaining hydrophilicity. By doing so, it can hold | maintain the state which a silica particle tends to move upwards at the time of drying, suppressing the aggregation of a silica particle effectively.
By using the above silica particles, it is possible to effectively avoid a state where the silica particles block the gap between the silicone emulsions and prevent the photocatalytic metal oxide particles from moving upward. You can concentrate on concentration.
With the above action, it is possible to provide a rain gutter capable of obtaining a high degree of photocatalytic decomposition activity even in a film having a long upward movement process, such as a thick film exceeding 2 μm.

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.
By doing so, it becomes easy to control the form of coating and modification on the silica surface.

  Further preferably, the photocatalytic metal oxide particles may be photocatalytic metal oxide particles that are not subjected to a treatment for reducing activity such as a silane modification treatment, a silicone modification treatment, a silane coating treatment, and a silicone coating treatment. . Nevertheless, according to the above action, the photocatalytic metal oxide particles can be concentrated on the surface at a high concentration, and a higher photocatalytic decomposition activity can be obtained without reducing the activity per photocatalytic metal oxide particle.

  However, as the photocatalytic metal oxide particles, photocatalytic metal oxide particles having a particle surface energy reduced by silane modification treatment, silicone modification treatment, silane coating treatment, silicone coating treatment, or the like may be used. By doing so, the photocatalytic metal oxide particles also form some agglomerated particles depending on the properties of the particles, but this can be effectively suppressed and the photocatalytic metal oxide particles can be concentrated at a higher concentration on the surface. There can be sex.

According to a preferred embodiment of the present invention, the hydrophilic silica particles have a total amount of hydroxyl groups and alkoxy groups bonded to silicon atoms of less than 6 mmol / g.
In this way, the silica particles can be easily moved upward at the time of drying while effectively suppressing the aggregation of the silica particles, so that the silica particles easily move upward, such as a thick film exceeding 2 μm, Even in a film having a long upward movement stroke, it becomes easier to provide a rain gutter capable of obtaining a high photocatalytic decomposition activity.

According to a preferred embodiment of the present invention, the curable silicone emulsion is 80% or more, preferably 85% or more, based on the total mass of the curable silicone emulsion, the photocatalytic metal oxide particles, and the hydrophilic silica particles. More preferably, it should be 90% or more. Here, the mass of the curable silicone emulsion is the mass of the solid content of the emulsion, and is determined by a constant weight value obtained by drying at 105 ° C.
By setting it to 80% or more, a high photocatalytic decomposition activity can be obtained even in a film having a long upward movement process, such as a thick film exceeding 2 μm, and a transparent photocatalytic layer can be formed when no colorant is added. It can be formed.
Furthermore, by making it 90% or more, it is possible to obtain a high photocatalytic decomposition activity even in a film having a long upward movement process, such as a thick film exceeding 5 μm, and a transparent photocatalyst when no colorant is added. A layer can be formed.

According to a preferred embodiment of the present invention, the average particle size of the curable silicone emulsion is larger than the average particle size of the photocatalytic metal oxide particles and the hydrophilic silica particles.
By doing so, the upward movement of the photocatalytic metal oxide particles and the hydrophilic silica particles becomes remarkable.
Accordingly, the silica particles are easily moved upward without being bound by the silicone emulsion, and even in a film having a long upward movement process such as a thick film exceeding 2 μm, it is possible to obtain a high photocatalytic decomposition activity. It becomes easier to provide the coating liquid.

In addition to the above “photocatalyst particles”, “hydrophilic silica particles”, and “curable silicone emulsion”, the coating liquid for rain gutters is not limited to the following, but “inorganic oxide particles other than hydrophilic silica particles”, “ "Metal or metal compound", "ultraviolet absorber", "light stabilizer", "surfactant", "organic antifungal agent" and the like can be blended.
Items related to “photocatalyst particles”, “hydrophilic silica particles”, “curable silicone emulsion”, “containing inorganic oxide particles other than hydrophilic silica particles”, “addition of metal or metal compound”, “ultraviolet absorption” All the contents of the photocatalyst coating solution described in the section of “Gills” are suitable for “mixing agent”, “blending light stabilizer”, “blending surfactant”, and “blending anti-algae”. Available to:

  In the coating solution for rain gutters of the present invention, a film forming aid having a boiling point of 100 ° C. or higher that is soluble in water or can be uniformly dispersed in water can be blended. This film-forming aid remains in the film even after most of the water has evaporated, and it provides fluidity to the film until it is completely cured, thereby repairing the film that was rough at the time of vaporization. It is given. In order to obtain a good film, the non-reactive film-forming aid must eventually disappear from the cured film, and does not contain hydroxyl groups that can be bonded to silicon atoms by transesterification. It is preferable. Therefore, the film forming aid is preferably an organic solvent having a boiling point of 100 ° C. or higher, preferably 100 to 250 ° C., particularly 100 to 200 ° C. If the boiling point is too high, it may easily remain in the film. 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 Examples include butylene glycol derivatives such as acetate, ketones such as cyclohexanone, esters such as butyl acetate, isobutyl acetate, γ-butyrolactone, propylene carbonate, and dibutyl phthalate. Particularly, 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 leveling properties. To preferred. Since these organic solvents are inferior in water solubility as compared with low boiling alcohols such as methanol and ethanol, they do not impair the stability of the emulsion and contribute only to the formation of a uniform film.

  The amount of the film forming aid added 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. If added in excess of 20 parts by weight, the amount of the film-forming aid remaining in the film after the curing is increased, and the film characteristics may be insufficient.

  The solvent of the raindrop coating liquid of the present invention is mainly water. As a result, it is possible to effectively prevent the odor and environmental pollution associated with the volatilization and evaporation of organic substances during coating film formation.

  Moreover, although the solid content concentration of the coating liquid for rain gutter is not specifically limited, 10-60 mass% is preferable at the point which is easy to apply | coat. 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.

  It should be noted that the contents described in the sections of “rain gutter” and “rain gutter coating liquid” can be arbitrarily combined.

Method for producing rain gutter The rain gutter of the present invention can be easily produced by applying the photocatalyst coating liquid on a substrate. 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. Preferable examples of the base material from the viewpoint of applications include outer wall building materials, building exteriors, window frames, window glasses, and films, sheets, seals, and the like for attaching to the article surface.
Particularly preferably, a substrate whose surface is enamel-coated or clear-coated is most preferable because the effect of the present invention can be fully enjoyed.

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

Example 1.
1.3 parts by mass of anatase-type titanium oxide particles (average crystallite size 10 nm), 8.7 parts by mass of silica particles (average particle size 50 nm) 5% surface-coated with trifunctional silane, 90 parts by mass of methylphenyl silicone emulsion A photocatalyst aqueous coating solution having a solid content concentration of 25% by mass was prepared and dried on a transparent acrylic 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, and it was observed that anatase-type titanium oxide particles and silica particles were present at a high concentration on the surface.
Moreover, when it observed from the surface of the photocatalyst coating body, the experimental stand which mounted the coating body was seen through.
About this photocatalyst coating body, the photocatalytic decomposition activity was confirmed by investigating NOx decomposition | disassembly performance. Here, the NOx decomposition function by the photocatalyst was performed by the test method of JIS R1701-1 “Testing method for air purification performance of photocatalytic material—Part 1: Nitrogen oxide removal performance”. As a result, ΔNOx exceeded 0.5 μmol, indicating a good result.

Example 2
1.3 parts by mass of anatase-type titanium oxide particles (average crystallite diameter 10 nm), 8.7 parts by mass of silica particles (average particle diameter 50 nm) 5% surface-coated with trifunctional silane, 90 parts by mass of dimethyl silicone emulsion were blended. A photocatalyst aqueous coating solution having a solid content concentration of 25% by mass was prepared and dried on a transparent acrylic 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, and it was observed that anatase-type titanium oxide particles and silica particles were present at a high concentration on the surface.
Moreover, when it observed from the surface of the photocatalyst coating body, the experimental stand which mounted the coating body was seen through.
About this photocatalyst coating body, the photocatalytic decomposition activity was confirmed by investigating NOx decomposition | disassembly performance. Here, the NOx decomposition function by the photocatalyst was performed by the test method of JIS R1701-1 “Testing method for air purification performance of photocatalytic material—Part 1: Nitrogen oxide removal performance”. As a result, ΔNOx exceeded 0.5 μmol, indicating a good result.

Claims (12)

A rain gutter having a photocatalyst layer on a substrate surface,
The photocatalyst layer is obtained by applying a photocatalyst coating liquid and drying it,
The photocatalytic coating liquid comprises photocatalytic metal oxide particles, hydrophilic silica particles, and a curable silicone emulsion,
The rain gutter characterized in that the hydrophilic silica particles are partially coated or modified with a substance having a hydrophobic group.   The rain gutter according to claim 1, wherein the substance having a hydrophobic group is a silane having a hydrophobic group and / or a silicone having a hydrophobic group.   The rain gutter according to claim 2, wherein the hydrophilic silica particles have a total amount of hydroxyl groups and alkoxy groups bonded to silicon atoms of less than 6 mmol / g.   The curable silicone emulsion is 80% or more based on a total mass of the curable silicone emulsion, the photocatalytic metal oxide particles, and the hydrophilic silica particles. The rain gutter according to item 1.   The rain gutter according to any one of claims 1 to 4, wherein the film thickness of the photocatalyst layer is more than 2 µm and less than 20 µm.   6. The rain according to claim 1, wherein an average particle size of the curable silicone emulsion is larger than an average particle size of the photocatalytic metal oxide particles and the hydrophilic silica particles.樋.   The rain gutter according to claim 1, wherein the photocatalyst layer is transparent. Photocatalytic metal oxide particles;
Hydrophilic silica particles,
A curable silicone emulsion;
With water,
The coating liquid for rain gutter characterized in that the hydrophilic silica particles are partially coated or modified with a substance having a hydrophobic group.   9. The coating solution for rain gutter according to claim 8, wherein the substance having a hydrophobic group is a silane having a hydrophobic group and / or a silicone having a hydrophobic group.   10. The raindrop coating liquid according to claim 9, wherein the hydrophilic silica particles have a total amount of hydroxyl groups and alkoxy groups bonded to silicon atoms of less than 6 mmol / g.   The curable silicone emulsion is 80% or more based on a total mass of the curable silicone emulsion, the photocatalytic metal oxide particles, and the hydrophilic silica particles. The coating solution for rain gutters according to item 1.   12. The rain according to claim 9, wherein an average particle size of the curable silicone emulsion is larger than an average particle size of the photocatalytic metal oxide particles and the hydrophilic silica particles. Coating liquid for vaginal.