JP2008094956A - Silicone coating composition, method for producing the same, and coated article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating composition curable into a coating film which can exhibit scratch resistance and UV shielding properties while keeping transparency to visible light and has weather resistance and durability high enough to withstand to long-term outdoor exposure, to provide a method for producing the same, and to provide an article coated with the same. <P>SOLUTION: Provided is a silicone composition comprising (A) a silicone resin prepared by (co)hydrolyzing and/or condensing at least one member selected from an alkoxysilane represented by formula (1): (R<SP>1</SP>)<SB>m</SB>(R<SP>2</SP>)<SB>n</SB>Si(OR<SP>3</SP>)<SB>4-m-n</SB>(wherein R<SP>1</SP>and R<SP>2</SP>are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group; R<SP>3</SP>is a 1-3C alkyl group; and m and n are each independently 0 or 1, provided that m+n=0, 1, or 2) and a condensate of a partial hydrolyzate thereof, (B) a rutile titanium oxide microparticle dispersion containing a dispersant, (C) a curing catalyst, and (D) a solvent, wherein the dispersion (B), the titanium oxide solids content is 0.1-15 mass% based on the entire weight of the solids constituents in the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a silicone coating composition, a method for producing the same, and a coated article using the composition. In particular, a silicone coating composition capable of forming a coating film that has both visible light transparency and ultraviolet shielding properties and excellent long-term weather resistance by coating on the surface of an organic resin base material such as plastic and heating and curing. And a coated article formed by coating the composition and the composition.

  Conventionally, hydrolyzable organosilane has been hydrolyzed or partially hydrolyzed as a coating agent that forms a surface protective coating for the purpose of imparting high hardness and scratch resistance to the surface of organic resin substrates such as plastics. A coating agent comprising the resulting composition, or a coating agent obtained by mixing colloidal silica with the composition is known.

  For example, JP-A-51-2736 (Patent Document 1), JP-A-53-130732 (Patent Document 2), and JP-A-63-168470 (Patent Document 3) include organoalkoxysilanes, There has been proposed a coating agent comprising the hydrolyzate of organoorganosilane and / or its partial condensate and colloidal silica, wherein an alkoxy group is converted into silanol with an excess of water. However, the coating films obtained by these coating agents have high hardness, good weather resistance, and excellent for protecting the base material, but are poor in toughness, and in coating films with a film thickness of 10 μm or more, they are being heated and cured. When taking out from the curing heating furnace, cracks are easily generated when a sudden temperature change occurs during use outdoors. Furthermore, in consideration of storage stability as a curing catalyst, these coating compositions have a relatively low molecular weight of the alkoxysilane hydrolyzate / condensate, despite the use of buffered basic catalysts. The silanols contained in these relatively low molecular weight products are very high and their content is large, so their condensation reactions occur gradually even at room temperature, and the The molecular weight is reduced and the hardness of the resulting coating film is reduced. Furthermore, there is a case in which gelation occurs and there is a problem relating to stability that it cannot be used as a coating agent. In order to solve these problems, in Japanese Patent Application Laid-Open No. 2005-314616 (Patent Document 4), by using a specific basic compound as a curing catalyst, storage stability of the liquid and crack resistance of the coating film, Compositions having both hardness and scratch resistance have been proposed.

However, in order to make a coating film that can withstand sunlight and wind and rain over a long period of time, there are still problems. The coating layer has a poor ability to cut off ultraviolet rays, and a phenomenon in which the resin base material, the primer layer for imparting base material adhesion, and the interface between them are deteriorated and discolored by the ultraviolet rays is observed. In order to prevent this, a method of adding an ultraviolet absorber to the primer layer and a method of introducing an ultraviolet-absorbing organic substituent into the organic resin constituting the primer via a chemical bond have been proposed. . The term “ultraviolet absorber” and “ultraviolet-absorbing organic substituent” as used herein refers to, for example, a substituent such as benzophenone, benzotriazole, and triazine, and an organic compound containing them (Patent Document 5: JP-A-4-106161). No., Patent Document 6: Japanese Patent No. 3106696, Patent Document 7: Japanese Patent Laid-Open No. 2001-47574).
The above method is a method in which an organic ultraviolet absorber is contained in the primer layer to cut the ultraviolet rays. However, the primer layer is primarily intended to improve the adhesion between the base substrate and the silicone layer. When the amount of the absorbent added is too large, problems such as a decrease in adhesion and a decrease in transparency occur. In addition, in outdoor exposure tests and accelerated weather resistance tests over a long period of time, it has become clear that UV blocking with only the primer layer is not sufficient for preventing deterioration and discoloration of the organic resin substrate.

  On the other hand, as a method for compensating for these drawbacks, a method of adding an organic ultraviolet absorber also to the silicone layer has been performed for some time. However, when these compounds are simply added to the coating composition, durability after forming a coating film, that is, bleeding or spillage from the surface of the UV absorber after long-term exposure occurs, resulting in poor durability. It is. Thus, a method using a silyl-modified organic ultraviolet absorber that can form a chemical bond with the siloxane compound as the main component of the coating layer has been disclosed (Patent Document 8: Japanese Patent Publication No. 61-54800). Patent Document 9: Japanese Patent Publication No. 3-14862, Patent Document 10: Japanese Patent Publication No. 3-62177, Patent Document 11: Japanese Patent Laid-Open No. 7-278525). This is because the ultraviolet absorber is firmly bonded to the siloxane matrix, and thus the durability is improved. On the other hand, the scratch resistance of the original coating layer is greatly reduced, or microcracks caused by the flexibility are reduced. The occurrence became remarkable. Thus, the method using an organic ultraviolet absorber has an essential drawback in that the hardness of the silicone film decreases as the amount added increases in order to increase the weather resistance.

  On the other hand, an attempt has been made to maintain hardness and scratch resistance by adding an inorganic compound having ultraviolet absorptivity. For example, in Japanese Patent Application Laid-Open No. 2004-238418 (Patent Document 12), a colloidal sol in which metal oxide fine particles mainly composed of titanium oxide are coated with a silicon compound is used as an ultraviolet cut agent. This coating agent can form a coating film that blocks ultraviolet rays of 320 nm or less while maintaining visible light permeability and scratch resistance. However, the titanium oxide colloidal sol exemplified in Patent Document 12 is an anatase type having a strong photocatalytic activity, and the primary particle diameter observed with a transmission electron microscope (TEM) is 30 nm or less. Is extremely large. Therefore, even if the surface is coated with a silicon compound or the like, the photocatalytic activity cannot be completely suppressed, and the weather resistance is insufficient, such as cracks occurring in the accelerated weather resistance test over a long period of time.

  The titanium oxide colloidal sol can be obtained by pressurizing and heating hydrated titanium oxide obtained by allowing hydrogen peroxide to act on a gel or sol of hydrated titanium oxide. In such a method using hydrogen peroxide, generally only anatase-type titanium oxide particles can be obtained, but in the course of this particle-forming reaction, a tin compound having a specific mass ratio is allowed to coexist to form a rutile type. It is also known that titanium oxide fine particles are produced (Patent Document 13: Japanese Patent No. 2783417). This rutile type sol is an example used to improve the film refractive index of a hard coat for a high refractive index eyeglass lens, as in the anatase type (Patent Document 14: JP-A-11-310755, Patent Document 15: JP 2000-204301, Patent Document 16: JP-A-2006-111702) have been reported. Further, the rutile type titanium oxide-tin oxide composite particles have weak photocatalytic activity as compared with the anatase type, but a technique relating to a surface antifouling coating using this activity is also disclosed (Patent Document 17). : Japanese Patent No. 3764820). That is, when a titanium oxide sol produced by a method using hydrogen peroxide as described above is contained in the coating film, it has photocatalytic activity even in the rutile type. As a result, when a long-term weather resistance test (accelerated weather resistance test corresponding to outdoor exposure for 5 years or more) is performed, the phenomenon of cracks in the coating film and peeling is inevitable. It is not sufficient as a shielding material.

  On the other hand, a rutile type titanium oxide used in the white pigment and cosmetics fields is generally known to produce fine particles by a method of hydrolyzing titanyl sulfate with heating, and further to carry out a surface coating treatment to suppress photocatalysis. (Patent Document 18: Japanese Patent No. 2878415). The particle shape of the anatase type fine particles synthesized using hydrogen peroxide is a cubic type, whereas the rutile type is a spindle type. In addition, the rutile type generally tends to have a larger major diameter as compared with fine particles synthesized by the action of hydrogen peroxide.

  As an application example of cosmetics, there is known a dispersion obtained by mechanically dispersing titanium oxide powder having a high ultraviolet shielding ability together with a dispersant using a bead mill or the like (Patent Document 19: JP 2002-338245 A). ). Titanium oxide used in these materials has a particle size that is small enough to have visible light permeability that does not exhibit bluish white, and is subjected to surface treatment in order to minimize skin roughness due to photocatalytic activity (Patent Document 20). : JP-A-9-99246). That is, these dispersions are excellent in ultraviolet shielding property and visible light transparency, and the photocatalytic activity is greatly suppressed.

As an example in which such a dispersion is applied to a coating, a high refractive index layer of an antireflection laminate coat for improving the visibility of a display or the like is known (Patent Document 21: JP 2001-166104 A, (Patent Document 22: Japanese Patent Laid-Open No. 2003-41152, Patent Document 23: Japanese Patent Laid-Open No. 2005-91990). These are for applying and curing a composition of a titanium oxide dispersion and a binder, and titanium oxide is added for the purpose of increasing the refractive index of the film, as in the case of a hard coat for eyeglass lenses. In general, the refractive index of the film is considered to be proportional to the volume of titanium oxide contained in the film. Therefore, in order to exhibit antireflection performance, it is necessary to clearly increase the refractive index of the film and contain a large amount of titanium oxide. It is necessary to let In fact, the content of fine particles based on the solid content in the composition described in the Examples of Patent Document 23 is at least 40% by mass, and in many cases, the content of titanium oxide was larger than that of the binder. . Therefore, when a large amount of titanium oxide is added in this way, the spindle type titanium oxide fine particles have a large major axis, so there is a possibility that the transparency of the coating film may be reduced even if aggregation is reduced as much as possible. At present, it is applied as a very thin film with a film thickness of about 0.1 μm. In addition, the photocatalytic activity of titanium oxide is not limited to light deterioration due to indoor use, but the weather resistance in outdoor use is insufficient.
As described above, various attempts have been made to improve the weather resistance, scratch resistance, etc. of the coating agent, but the cured coating film exhibits scratch resistance and UV shielding properties while maintaining the transparency of visible light. Furthermore, there is no coating composition that satisfies all the weather resistance and durability that can withstand long-term outdoor exposure.

JP-A 51-2736 JP-A-53-130732 JP 63-168470 A JP 2005-314616 A JP-A-4-106161 Japanese Patent No. 3106696 JP 2001-47574 A Japanese Patent Publication No. 61-54800 Japanese Patent Publication No. 3-14862 Japanese Patent Publication No. 3-62177 JP-A-7-278525 JP 2004-238418 A Japanese Patent No. 2783417 JP-A-11-310755 JP 2000-204301 A JP 2006-111702 A Japanese Patent No. 3764820 Japanese Patent No. 2878415 JP 2002-338245 A JP-A-9-99246 JP 2001-166104 A JP 2003-41152 A JP 2005-91990 A

  Accordingly, the present invention provides a coating composition that has a weather resistance and durability that allows the cured coating film to exhibit scratch resistance and UV shielding while maintaining the transparency of visible light, and can withstand long-term outdoor exposure, It is an object of the present invention to provide a manufacturing method and a coated article coated with the composition.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in a coating composition using a rutile-type titanium oxide dispersion as an ultraviolet shielding agent, a specific coating is applied and the rutile is extremely suppressed in photocatalytic activity. A type of titanium oxide added with a specific dispersant and pulverized and dispersed is added to the coating composition at a minimum so that a cured coating film using the composition maintains transparency of visible light. The present inventors have found that long-term weather resistance and crack resistance in outdoor exposure, which have been achieved, have achieved scratch resistance and UV shielding properties, and have not been realized so far.

That is, the present invention provides the following silicone coating composition.
[1] (A) The following general formula (1):
(R ¹ ) _m (R ² ) _n Si (OR ³ ) _4-mn (1)
Wherein R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ³ is an alkyl group having 1 to ³ carbon atoms, and m and n are each independently 0 or 1 and m + n is 0, 1 or 2.)
A silicone resin obtained by (co) hydrolysis / condensation of at least one selected from alkoxysilanes represented by the following and partial hydrolysis-condensation products thereof,
(B) A rutile-type titanium oxide fine particle dispersion containing a dispersant having an average particle diameter (volume average particle diameter D50) of 0.2 μm or less measured by a dynamic light scattering method,
(C) a curing catalyst,
(D) The silicone coating composition which contains a solvent and (B) titanium oxide solid content is 0.1-15 mass% with respect to the total amount of solids in a composition.
[2] The silicone coating composition according to [1], wherein the rutile titanium oxide used for the component (B) is surface-treated with a compound containing one or more elements selected from silicon, aluminum, and zirconium. object.
[3] The dispersion of component (B) is prepared by pulverizing agglomeration of rutile titanium oxide powder in a dispersion medium in the presence of a dispersant [1] or [2] The silicone coating composition according to [2].
[4] The dispersant used for the component (B) is an organic polymer containing one or more substituents selected from a carboxyl group, a phosphate group, and a salt thereof [1], [2 The silicone coating composition according to [3].
[5] The 95% volume particle size (D95) measured by the dynamic light scattering method of the titanium oxide particles in the dispersion of the component (B) is 0.5 μm or less [1] to [1] [4] The silicone coating composition according to any one of [4].
[6] The silicone coating composition according to any one of [1] to [5], further comprising (E) colloidal silica.
[7] (I) A step of preparing a dispersion of component (B) by mixing a dispersion medium, a dispersant and rutile-type titanium oxide powder, and pulverizing and dispersing with a bead mill;
(II) Adding a water-containing liquid containing the component (B) produced in the step (I) to at least one selected from the alkoxysilane represented by the above formula (1) and a partial hydrolysis condensate thereof. A method for producing a silicone coating composition, comprising the step of producing a silicone resin as component (A) by hydrolytic condensation.
[8] The cured film of the silicone coating composition according to any one of [1] to [6] is coated on at least one surface of the substrate directly or via at least one other layer. Coated article.

  According to the present invention, the cured coating film exhibits scratch resistance and UV shielding properties while maintaining the transparency of visible light, and further has a weather resistance and durability that can withstand long-term outdoor exposure. Can be provided.

Hereinafter, the composition of the present invention will be described in detail.
Ingredient (A)
The component (A) used in the present invention has the following general formula (1):
(R ¹ ) _m (R ² ) _n Si (OR ³ ) _4-mn (1)
Wherein R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ³ is an alkyl group having 1 to ³ carbon atoms, and m and n are each independently 0 or 1 and m + n is 0, 1 or 2.)
A silicone resin obtained by (co) hydrolysis / condensation of at least one selected from the alkoxysilanes represented by the formula (1) and partial hydrolysis condensates thereof.

In the above formula, R ¹ and R ² are a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, for example, a hydrogen atom; a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, Alkyl groups such as heptyl group and octyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; alkenyl groups such as vinyl group and allyl group; aryl groups such as phenyl group; chloromethyl group, γ-chloropropyl group, 3, Halogen-substituted hydrocarbon groups such as 3,3-trifluoropropyl group; γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl group, γ-mercaptopropyl group, γ-aminopropyl (Meth) acryloxy, epoxy, mercapto, amino group-substituted hydrocarbon group, etc. can be exemplified . Among these, an alkyl group is preferable when used for applications requiring scratch resistance and weather resistance, and an epoxy or (meth) acryloxy-substituted hydrocarbon group is preferable when toughness and dyeability are required. .

R ³ is an alkyl group having 1 to ³ carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, and an i-propyl group. Among these, a methyl group and an ethyl group are preferable in consideration of the high reactivity of the hydrolysis condensation and the high vapor pressure of the alcohol R ³ OH to be produced and the ease of distilling off.

As an example of the above formula, when m = 0 and n = 0, it is a tetraalkoxysilane represented by the general formula: Si (OR ³ ) ₄ , or a partial hydrolysis condensate (a-1) thereof. Specific examples of such tetraalkoxysilanes or partial hydrolysis condensates thereof include partial hydrolysis condensates of tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetramethoxysilane (trade name “ M silicate 51 “manufactured by Tama Chemical Industry Co., Ltd., trade name“ MSI51 ”manufactured by Colcoat Co., Ltd.), trade names“ MS51 ”and“ MS56 ”manufactured by Mitsubishi Chemical Corporation), partially hydrolyzed condensate of tetoethoxysilane (Product names “Silicate 35”, “Silicate 45”, manufactured by Tama Chemical Industry Co., Ltd., product names “ESI40”, “ESI48” manufactured by Colcoat Co., Ltd.), Co-partial hydrolytic condensation of tetramethoxysilane and tetraethoxysilane Product (trade name "FR-3" manufactured by Tama Chemical Industry Co., Ltd., trade name "EMSi48" Colcoat ( ) Co., Ltd.) and the like can be mentioned.

When m = 1, n = 0 or m = 0, n = 1, a trialkoxysilane represented by the general formula: R ¹ Si (OR ³ ) ₃ or R ² Si (OR ³ ) ₃ , or It is a partial hydrolysis-condensation product (a-2). Specific examples of such trialkoxysilanes or partially hydrolyzed condensates thereof include hydrogentrimethoxysilane, hydrogentriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, and ethyltrimethoxysilane. , Ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, γ-methacryloxypropyltrimethoxy Silane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3- Trifluoropropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (2-aminoethyl) aminopropyltri Methoxysilane, partially hydrolyzed condensate of methyltrimethoxysilane (trade names “KC-89S”, “X-40-9220” manufactured by Shin-Etsu Chemical Co., Ltd.), methyltrimethoxysilane and γ-glycidoxypropyltri Partial hydrolysis condensation of methoxysilane (Trade name "X-41-1056" manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

When m = 1 and n = 1, it is a dialkoxysilane represented by the general formula: (R ¹ ) (R ² ) Si (OR ³ ) ₂ , or a partially hydrolyzed condensate (a-3) thereof. Specific examples of such dialkoxysilanes or partially hydrolyzed condensates thereof include methylhydrogendimethoxysilane, methylhydrogendiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylethyldimethoxysilane, and diethyldimethoxysilane. , Diethyldiethoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, diisopropyldimethoxysilane, phenylmethyldimethoxysilane, vinylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxy Silane, β- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacrylate Examples include yloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, and N- (2-aminoethyl) aminopropylmethyldimethoxysilane.

  The (A) component silicone resin may be prepared using the above-mentioned (a-1), (a-2) and (a-3) in an arbitrary ratio, but further storage stability, scratch resistance, In order to improve crack resistance, (a-1) is added in an amount of 1 to 50 Si mol%, (a-) with respect to a total of 100 Si mol% of (a-1), (a-2), and (a-3). 2) is preferably used in a proportion of 50 to 99 Si mol%, and (a-3) is preferably used in a proportion of 0 to 10 Si mol%. Furthermore, (a-1) is 1 to 30 Si mol%, and (a-2) is 70. It is preferable to use -99Si mol% and (a-3) in a proportion of 0-10Si mol%. At this time, when the main component (a-2) is less than 50 Si mol%, the crosslinking density of the resin is small, so that the curability is low and the hardness of the cured film tends to be low. On the other hand, when (a-1) is used in excess of 50 Si mol%, the crosslink density of the resin becomes too high, and the toughness may be lowered, making it difficult to avoid cracks.

  In addition, Si mol% is a ratio in the total Si mole, and the Si mole is a monomer having a molecular weight of 1 mole, and in the case of a dimer, the number obtained by dividing the average molecular weight by 2 is 1 mole. It is.

  When the (A) component silicone resin is produced, (a-1), (a-2), and (a-3) may be (co) hydrolyzed and condensed by a known method. For example, an alkoxysilane of (a-1), (a-2), (a-3) or a partial hydrolysis-condensation product thereof alone or a mixture thereof is water having a pH of 1 to 7.5, preferably 2 to 7 (Co) hydrolysis with At this time, a material in which fine metal oxide particles such as silica sol are dispersed in water may be used. To adjust to this pH range and to promote hydrolysis, hydrogen fluoride, hydrochloric acid, nitric acid, formic acid, acetic acid, propionic acid, oxalic acid, citric acid, maleic acid, benzoic acid, malonic acid, glutaric acid, glycol Organic acids and inorganic acids such as acids, methanesulfonic acid and toluenesulfonic acid, or solid acid catalysts such as cation exchange resins having carboxylic acid groups or sulfonic acid groups on the surface, or water-dispersed metals such as acidic water-dispersed silica sols Oxide fine particles may be used as a catalyst. In addition, metal oxide fine particles such as silica sol dispersed in water or an organic solvent may coexist at the time of hydrolysis. Furthermore, in the rutile-type titanium oxide fine particle dispersion which is a component (B) described later, when the dispersion medium is water or a water-soluble organic solvent, water, an acidic hydrolysis catalyst, and Hydrolysis / condensation reaction may be carried out by mixing alkoxysilane. In this case, there is a possibility that the surface of the titanium oxide as the component (B) and the hydrolysis condensate of alkoxysilane partially react, but this is more preferable because the dispersibility of the titanium oxide (B) is improved.

In this hydrolysis, the amount of water used is 20 masses of water with respect to a total of 100 mass parts of the alkoxysilanes of (a-1), (a-2) and (a-3) and / or partial hydrolysis condensates thereof. It is sufficient that the amount of water is in the range of 3,000 parts by weight to 3,000 parts by weight. However, the use of excess water not only lowers the efficiency of the apparatus but also makes the final composition a coating property due to the influence of remaining water, drying. It may also cause a decline in sex. Furthermore, in order to improve storage stability, scratch resistance, and crack resistance, the content is preferably 50 parts by mass or more and less than 150 parts by mass. If the amount of water is small, the polystyrene-reduced number average molecular weight in gel permeation chromatography (GPC) analysis of the silicone resin to be obtained may not increase to the optimum region described later, and if it is too much, the raw material contained in the silicone resin to be obtained Unit formula derived from (a-2): R′SiO _{(3-p) / 2} (OX) _p {wherein R ′ is R ¹ or R ² , X is a hydrogen atom or R ³ , R ¹ , R ² and R ³ are the same as described above, and p is an integer of 0 to 3. } R′SiO _3/2 in the unit represented by {where R ′ is the same as above} may not reach the optimum range for maintaining the crack resistance of the coating film. .

  Hydrolysis may be performed by dropping or adding water into alkoxysilane or a partial hydrolysis condensate thereof, or conversely dropping or adding alkoxysilane or a partial hydrolysis condensate thereof into water. In this case, an organic solvent may be contained, but it is preferable that no organic solvent is contained. This is because the number average molecular weight in terms of polystyrene in the GPC analysis of the obtained silicone resin tends to be smaller as the organic solvent is contained.

  In order to obtain the silicone resin as component (A), it is necessary to condense following the hydrolysis. Condensation may be performed continuously following hydrolysis, and is usually performed under heating at a liquid temperature of room temperature or 100 ° C. Gelation may occur at temperatures higher than 100 ° C. Furthermore, condensation can be accelerated | stimulated by distilling off the alcohol produced | generated by hydrolysis under 80 degreeC or more and a normal pressure or pressure reduction. Furthermore, for the purpose of promoting condensation, a condensation catalyst such as a basic compound, an acidic compound, or a metal chelate compound may be added. Before or during the condensation step, an organic solvent may be added for the purpose of adjusting the degree of progress and concentration of the condensation, and a metal oxide fine particle such as silica sol dispersed in water or an organic solvent, You may add the titanium oxide dispersion liquid which is the component (B) of this invention. In general, silicone resin undergoes condensation, increases in molecular weight, and decreases in solubility in water and generated alcohol. Therefore, as an organic solvent to be added, silicone resin is well dissolved and has a boiling point of 80 ° C. or higher. The organic solvent having a relatively high polarity is preferred. Specific examples of such organic solvents include alcohols such as isopropyl alcohol, n-butanol, isobutanol, t-butanol and diacetone alcohol; methyl propyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol and the like. Ketones; ethers such as dipropyl ether, dibutyl ether, anisole, dioxane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate; propyl acetate, butyl acetate, cyclohexyl acetate, etc. Examples include esters.

  The number average molecular weight in terms of polystyrene in GPC analysis of the silicone resin obtained by this condensation is preferably 1,500 or more, more preferably 1,500 to 50,000, and 2,000 to 20,000. More preferably. If the molecular weight is lower than this range, the toughness of the coating film is low and cracks tend to occur. On the other hand, if the molecular weight is too high, the hardness tends to be low, and the resin in the coating film is phase-separated. May cause whitening of the coating film.

Ingredient (B)
The component (B) rutile-type titanium oxide fine particle dispersion is a liquid in which titanium oxide fine particles are dispersed in a dispersion medium. There are three types of crystal forms of titanium oxide: rutile, anatase, and brookite. In the present invention, the purpose is to develop long-term weather resistance and crack resistance of the coating film, and from this viewpoint, the photocatalytic activity is the lowest. A rutile type having 90% by mass or more is used.

  These fine particles may contain metal oxides other than titanium oxide, such as silica, alumina, zirconia, zinc oxide, etc., but the titanium oxide content in the particles is preferably 60 to 100% by mass. Furthermore, it is preferable that it is 70-100 mass%.

  The rutile-type titanium oxide fine particles preferably have a primary particle diameter of 1 to 500 nm, more preferably about 2 to 300 nm as observed with a transmission electron microscope (TEM). When the shape is not spherical, the major axis is 500 nm or less, preferably 300 nm or less. These fine particles, unlike pigment-grade titanium oxide, have the optical property of transmitting visible light at a high rate while shielding light in the ultraviolet region, and are widely marketed for cosmetic applications such as sunscreen creams. Those are preferred. Specifically, fine particle titanium oxide MT series (MT-01, MT-05, MT-100Z, MT-100AQ, MT-150W, etc.) manufactured by Teika Co., Ltd., TTO series (TTO-51) manufactured by Ishihara Sangyo Co., Ltd. (A), TTO-55 (A), TTO-55 (B)), STR-60C-LP, STR-100W manufactured by Sakai Chemical Co., Ltd.

  The surface of these fine particles is surface treated with hydrous silicic acid, aluminum hydroxide, fatty acid salts, polyhydric alcohols, silicone, etc. for hydrophilicity / lipophilic control, improvement of dispersibility, suppression of photocatalytic activity, etc. It is common. Also in the present invention, it is necessary to select a surface-treated powder suitable for the dispersion medium of the component (B) dispersion. When the dispersion medium is a polar solvent such as water or alcohol, an inorganic treatment such as aluminum, silicon, zirconium hydroxide or oxide is preferable. On the other hand, when the dispersion medium is a nonpolar solvent such as hydrocarbon or toluene, it is preferable to select a powder having a lipophilic surface treated with a fatty acid salt or silicone. In particular, in the case where hardness, adhesion, and scratch resistance are expressed in a coating film obtained from a coating composition containing the same, the surface treatment preferably includes treatment with an inorganic compound containing aluminum, silicon, and zirconium. Further, those coated with a dense silica layer obtained by further densifying hydrous silicic acid are particularly preferred.

  In general, these fine powder particles have a very strong cohesive force, and the primary particles are aggregated in clusters to form secondary aggregates. Therefore, simply adding these agglomerated powders to the dispersion medium as it is and stirring and mixing does not give a dispersion of the component (B) of the present invention. The dispersion that characterizes the present invention is a coating solution by mechanically applying energy to rutile titanium oxide powder to break up agglomeration between particles, and finely pulverizing the particles to a size close to the original primary particle size. Visible light transparency when made into a film can be expressed.

  The particle diameter of the component (B) dispersion defined in the present invention is such that the average particle diameter (volume average particle diameter D50) measured by the light scattering method is 0.2 μm or less. If it exceeds 0.2 μm, the visible light transmittance of the coating film is lowered, which is not preferable. More preferably, D50 is 0.1 μm or less. These particle size distributions do not depend on the measuring device, but here are defined by values measured by Nanotrac UPA-EX150 manufactured by Nikkiso Co., Ltd. or LA-910 Horiba Seisakusho Co., Ltd. Further, the 95% volume average particle diameter (D95) measured by the light scattering method is preferably 0.5 μm or less, and more preferably 0.45 μm or less. When the thickness exceeds 0.5 μm, the transparency is remarkably lowered or the adhesion to the substrate is lowered, which is not preferable. In addition, the lower limit of the average particle diameter is usually 0.003 μm or more, particularly 0.005 μm or more in D50.

As the mechanical pulverizing / dispersing device, known ones such as a bead mill, a jet mill, an attritor, and a sand mill can be used. In particular, when a bead mill using beads is used, the component (B) of the present invention is short. It is easy to obtain in time and is preferable. As specific examples of the bead mill, Mini Zetas manufactured by Ashizawa Finetech Co., Ltd., Labstar, Star Mill LMZ, Star Mill ZRS, Ultra Apex Mill manufactured by Kotobuki Industries Co., Ltd., Max Visco Mill manufactured by Imex Co., Ltd., and the like can be used. The dispersion time varies depending on the bead diameter, the bead material used, the peripheral speed of the bead mill, etc., but generally the bead diameter is about 0.03 to 0.5 mm, and the use of ceramic beads such as alumina and zirconia is suitable. The grinding time in the bead mill is preferably about 20 minutes to 5 hours, more preferably about 30 minutes to 3 hours.
The dispersion medium can be used regardless of whether it is water or an organic solvent, but more preferably water, alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, diacetone alcohol, propylene glycol monomethyl ether Ethers such as propylene glycol monoethyl ether, polar solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone, ertels such as ethyl acetate and butyl acetate, and mixed solvents thereof are preferable.

  When pulverizing and dispersing, it is necessary to add a dispersant from the viewpoint of dispersion stability. The dispersant has an organic functional group that adsorbs and aligns on the surface of the inorganic powder, and plays a role in protecting fine particles that have been refined by pulverization. Therefore, when preparing a dispersion with high dispersion stability, Is essential. Examples of the organic functional group include a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, an amino group, an imino group, and salts thereof, an amide group, and an acetylacetonate group. In particular, a carboxyl group, a phosphate group, and sodium salts and ammonium bases thereof are preferable. As a compound having such a functional group and further contributing to improvement in dispersibility, an organic polymer having these functional groups in the side chain is preferable. More specifically, an organic material containing at least one functional monomer such as (meth) acrylic acid, phosphoric acid group-containing (meth) acrylate, hydroxyalkyl (meth) acrylate, maleic anhydride, and sulfonic acid group-containing styrene. A polymer, and more preferably a polyacrylate solution containing (meth) acrylic acid, maleic anhydride, and phosphoric acid group-containing (meth) acrylate is preferred. As specific product names, Pois 520, 521, 532A, 2100 or more manufactured by Kao Corporation, Disperbyk102, 180, 190 BYK, Aron T-40 Toagosei Co., Ltd., or the like can be used.

  These dispersants are preferably allowed to coexist when the rutile titanium oxide powder and the dispersion medium are mechanically pulverized and dispersed with a bead mill. When the dispersion is added after mechanically pulverizing and dispersing only with the titanium oxide powder and the dispersion medium, the aggregation may not be solved up to the target average particle diameter of the dispersion.

  The titanium oxide solid content concentration of the component (B) dispersion is preferably 1 to 80% by mass, more preferably 2 to 65% by mass. If the amount is less than 1% by mass, the total solid concentration after adding the silicone resin (A) is too small, and a coating film having an appropriate film thickness cannot be obtained. If it exceeds 80% by mass, inconvenience in handling such as an increase in viscosity tends to occur, which is not suitable. In addition, the usage-amount of the said dispersing agent is 0.5-30 mass parts by a dispersing agent active ingredient with respect to 100 mass parts of titanium oxide solid content, Preferably 1-20 mass parts is preferable. If the amount is less than 0.5 parts by mass, the effect of adding a dispersant does not appear, so that it is not suitable. When the amount is more than 30 parts by mass, an excessive dispersant is unsuitable because it causes a decrease in scratch resistance and weather resistance of the coating film.

  It is preferable to add a dispersion in an amount such that the solid content of titanium oxide in the component (B) is 0.1 to 15% by mass, more preferably 0.3 to 10% by mass with respect to the total solid content of the composition. . If the titanium oxide is less than 0.1%, it is not suitable because the expected ultraviolet shielding ability cannot be obtained, and if it exceeds 15% by mass, it becomes difficult to maintain the visible light transparency of the coating film. After all it is not preferable.

Ingredient (C)
As the component (C), a curing catalyst used in a silicone coating composition known in the prior art and the like can be used. Specifically, it is a curing catalyst that promotes a reaction in which a condensable group such as a silanol group or an alkoxy group contained in the silicone resin (A) is condensed. For example, lithium hydroxide, sodium hydroxide, potassium hydroxide , Sodium methylate, sodium propionate, potassium propionate, sodium acetate, potassium acetate, sodium formate, potassium formate, trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, n-hexylamine, tributylamine, diazabicycloundecene (DBU), basic compounds such as dicyandiamide; tetraisopropyl titanate, tetrabutyl titanate, titanium acetylacetonate, aluminum triisobutoxide, aluminum triisopropoxide, tris ( Cetylacetonate) aluminum, diisopropoxy (ethylacetoacetate) aluminum, aluminum perchlorate, aluminum chloride, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin octylate, dibutyltin laurate Metal-containing compounds such as: acidic compounds such as p-toluenesulfonic acid and trichloroacetic acid. Of these, sodium propionate, sodium acetate, sodium formate, trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, tris (acetylacetonato) aluminum, and diisopropoxy (ethylacetoacetate) aluminum are particularly preferable.

Furthermore, in addition to curability and crack resistance, the following can be used as a curing catalyst more suitable for maintaining the storage stability of the coating composition.
The following general formula (2):
[(R ⁴ ) (R ⁵ ) (R ⁶ ) (R ⁷ ) M] ⁺ · X ⁻ (2)
(R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently an alkyl group having 1 to 18 carbon atoms which may be substituted with a halogen atom, and each of R ⁴ , R ⁵ , R ⁶ and R ⁷ is The sum of the substituent steric effect constants Es of Taft-Dubois is −0.5 or less, M is an ammonium cation or a phosphonium cation, and X ⁻ is a halogen anion, a hydroxide anion, or a carboxy having 1 to 4 carbon atoms. Rate anion.)
It is a compound which does not contain an aromatic group in the molecule | numerator represented by these.

Here, Taft-Dubois substituent steric effect constant Es is a relative rate based on the methyl group CH ₃ in the esterification reaction rate under acidic conditions of a substituted carboxylic acid, and is represented by the following formula {J. Org. Chem. 45, 1164 (1980), J. MoI. Org. Chem. 64, 7707 (1999)}.
Es = log (k / k0)
(K is the acidification esterification reaction rate of the substituted carboxylic acid under specific conditions, and k0 is the acidification esterification reaction rate of the methyl group-substituted carboxylic acid under the same conditions.)

  The Taft-Dubois substituent steric effect constant Es is a general index representing the steric bulk of the substituent, for example, methyl group: 0.00, ethyl group: -0.08, n-propyl group. : -0.31, n-butyl group: -0.31, indicating that the smaller Es is, the more sterically bulky.

In the present invention, the sum of Es in R ⁴ , R ⁵ , R ⁶ and R ⁷ in the formula (2) needs to be −0.5 or less. When the total of Es is larger than −0.5, the storage stability as a coating composition is reduced, cracking or whitening occurs after coating or after a water resistance test, adhesion, particularly water adhesion, Boiling adhesion decreases. This is because, when the sum of Es is larger than −0.5 (for example, R ⁴ , R ⁵ , R ⁶ , and R ⁷ are methyl groups), the corresponding curing catalyst represented by the formula (2) has high catalytic activity. The storage stability of the coating composition tends to decrease. Moreover, the coating film becomes very hygroscopic and causes an abnormality in the coating film after the water resistance test. In addition, the sum of Es in R ⁴ , R ⁵ , R ⁶ , and R ⁷ is usually −3.2 or more, particularly −2.8 or more.

In the above formula, the alkyl group having 1 to 18, preferably 1 to 12 carbon atoms which may be substituted with a halogen atom of R ⁴ , R ⁵ , R ⁶ and R ⁷ includes a methyl group, an ethyl group, and a propyl group. Alkyl groups such as butyl group, pentyl group, hexyl group, heptyl group, octyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group; chloromethyl group, γ-chloropropyl group, 3,3,3-trifluoropropyl And halogen-substituted hydrocarbon groups such as a group.

M is an ammonium cation or a phosphonium cation, X ⁻ is a halogen anion, a hydroxide anion or a carboxylate anion having 1 to 4 carbon atoms, and is preferably a hydroxide anion or an acetate anion.

  Specific examples of such a curing catalyst include, for example, tetra n-propylammonium hydroxide, tetra n-butylammonium hydroxide, tetra n-pentylammonium hydroxide, tetra n-hexylammonium hydroxide, tetracyclohexylammonium hydroxide. Tetrakis (trifluoromethyl) ammonium hydroxide, trimethylcyclohexylammonium hydroxide, trimethyl (trifluoromethyl) ammonium hydroxide, trimethyl t-butylammonium hydroxide, tetra n-propylphosphonium hydroxide, tetra n-butylphosphonium hydroxide Tetra n-pentylphosphonium hydroxide, tetra n-hexyl phosphonium hydroxide, tetracyclohexyl Hydroxides such as suphonium hydroxide, tetrakis (trifluoromethyl) phosphonium hydroxide, trimethylcyclohexylphosphonium hydroxide, trimethyl (trifluoromethyl) phosphonium hydroxide, trimethyl t-butylphosphonium hydroxide, these hydroxides and halogens Examples thereof include a salt with an acid and a salt with a carboxylic acid having 1 to 4 carbon atoms. Among these, tetrapropylammonium hydroxide, tetrapropylammonium acetate, tetrabutylammonium hydroxide, tetrabutylammonium acetate, tetrabutylphosphonium hydroxide, and tetrabutylphosphonium acetate are preferable. These may be used alone or in combination of two or more, and may be used in combination with the above-mentioned known curing catalyst.

  The blending amount of the component (C) is not particularly limited as long as it is an amount effective for curing the silicone resin of the component (A), but specifically, the solid content of the silicone resin is not limited. 0.0001 to 30% by mass, more preferably 0.001 to 10% by mass. If it is less than 0.0001% by mass, curing may be insufficient and the hardness may decrease, and if it is more than 30% by mass, cracks may easily occur in the coating film, and water resistance may decrease.

Ingredient (D)
The component (D) is a solvent and is not particularly limited as long as it can dissolve the components (A) to (C), but an organic solvent having a high polarity is preferably the main solvent. Specific examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol, isobutanol, t-butanol, diacetone alcohol; methyl propyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol Ketones such as: dipropyl ether, dibutyl ether, anisole, dioxane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc .; ethyl acetate, propyl acetate, butyl acetate And esters such as cyclohexyl acetate, and one or more selected from the group consisting of these The mixture can be used.

  (D) As addition amount of a component, it is preferable to use the quantity which makes solid content concentration of the silicone coating composition of this invention 1-30 mass%, especially 5-25 mass%. Outside this range, defects may occur in the coating film coated and cured with the composition. If the concentration is less than the above range, sagging, twisting, and spotting are likely to occur in the coating film, and the desired hardness and scratch resistance may not be obtained. If the concentration exceeds the above range, the coating film may be easily brushed, whitened or cracked.

Ingredient (E)
The component (E), colloidal silica, can be added in an appropriate amount when it is particularly desired to enhance the hardness and scratch resistance of the coating film. Nanosized silica having a particle size of about 5 to 50 nm is colloidally dispersed in a medium of water or an organic solvent, and commercially available water dispersion and organic dispersion types can be used. Specific examples include Snowtex-O, OS, OL, methanol silica sol manufactured by Nissan Chemical Industries, Ltd. The amount of colloidal silica added is 0 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the silicone resin solid content of the component (A).

  In the silicone coating composition of the present invention, a pH adjuster, a leveling agent, a thickener, a pigment, a dye, metal oxide fine particles, a metal powder, an antioxidant, an ultraviolet absorber, an ultraviolet stabilizer, if necessary A heat ray reflection / absorption imparting agent, flexibility imparting agent, antistatic agent, antifouling property imparting agent, water repellency imparting agent and the like can be added within a range that does not adversely affect the effects of the present invention.

  In order to obtain further storage stability of the silicone coating composition of the present invention, the pH of the liquid is preferably 2 to 7, more preferably 3 to 6. If the pH is outside this range, the storage stability may be lowered. Therefore, a pH adjuster may be added to adjust the pH to the above range. When the pH of the silicone coating composition is outside the above range, if it is more acidic than this range, it may be adjusted by adding a basic compound such as ammonia or ethylenediamine, and if it is basic, What is necessary is just to adjust pH using acidic compounds, such as hydrochloric acid, nitric acid, an acetic acid, and a citric acid. However, the adjustment method is not particularly limited.

  When the cured coating film of the silicone coating composition of the present invention is based on an organic resin or wood product, an ultraviolet absorber other than the component (B) of the present invention is used for the purpose of preventing yellowing of the substrate and surface degradation. Although an ultraviolet stabilizer may be added, an ultraviolet absorber and / or an ultraviolet stabilizer having good compatibility with the silicone coating composition of the present invention and low volatility are preferable.

  As the ultraviolet absorber, in addition to the rutile-type titanium oxide described in the component (B), a known inorganic oxide such as zinc oxide, cerium oxide, zirconium oxide, etc., and titanium, zinc, Metallic chelate compounds such as zirconium, and (partial) hydrolysates and condensates of inorganic and organic compounds can be used. As organic examples, compound derivatives whose main skeleton is hydroxybenzophenone, benzotriazole, cyanoacrylate, or triazine are preferable. Furthermore, a polymer such as a vinyl polymer containing these ultraviolet absorbers in the side chain, a copolymer with other vinyl monomers, a silylation-modified ultraviolet absorber, or a (partial) hydrolysis condensate thereof may be used.

Specifically, 2,4-dihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2 -Hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-n-benzyloxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone 2,2′-dihydroxy-4,4′-diethoxybenzophenone, 2,2′-dihydroxy-4,4′-dipropoxybenzophenone, 2,2′-dihydroxy-4,4′-dibutoxybenzophenone, 2, , 2'-dihydroxy-4-methoxy-4'-propoxybenzophenone, 2,2'-dihi Droxy-4-methoxy-4'-butoxybenzophenone, 2,3,4-trihydroxybenzophenone, 2- (2-hydroxy-5-t-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t- Octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, ethyl-2-cyano-3,3-diphenyl acrylate, 2-ethylhexyl-2-cyano-3, (Co) polymer of 3-diphenyl acrylate, 2- (2-hydroxy-4-hexyloxyphenyl) -4,6-diphenyltriazine, 2-hydroxy-4- (2-acryloxyethoxy) benzophenone, 2- ( Of 2′-hydroxy-5′-methacryloxyethylphenyl) -2H-benzotriazole ) Polymer, reaction product of 2,4-dihydroxybenzophenone and γ-glycidoxypropyltrimethoxysilane, 2,2 ′, 4,4′-tetrahydroxybenzophenone and γ-glycidoxypropyltrimethoxysilane Examples include reactants and hydrolysates thereof (partial). Two or more of these organic ultraviolet absorbers may be used in combination.
It is preferable that the compounding quantity of a ultraviolet absorber is 0.1-100 mass% with respect to solid content of a silicone coating composition. More preferably, it is 0.3-30 mass%.

As the UV stabilizer, one having at least one cyclic hindered amine structure in the molecule, good compatibility with the silicone coating composition of the present invention, and low volatility is preferable. Specific examples of the ultraviolet light stabilizer include 3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione, N-methyl-3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione, N-acetyl-3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) Pyrrolidine-2,5-dione, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2 , 3,4-Butane Tracarboxylate, condensate of 1,2,3,4-butanetetracarboxylic acid with 2,2,6,6-tetramethyl-piperidinol and tridecanol, 8-acetyl-3-dodecyl-7,7,9, 9-tetramethyl-1,3,8-triazaspiro [4,5] decane-2,4-dione, 1,2,3,4-butanetetracarboxylic acid and 1,2,6,6-pentamethyl-4- Condensates of piperidinol and β, β, β, β′-tetramethyl-3,9- (2,4,8,10-tetraoxaspiro [5,5] undecane) diethanol, 1,2,3,4 -Butanetetracarboxylic acid, 2,2,6,6-pentamethyl-4-piperidinol and β, β, β, β′-tetramethyl-3,9- (2,4,8,10-tetraoxaspiro [5 , 5] Undecane) with diethanol For the purpose of immobilizing a compound or a light stabilizer, a silylated modified light stabilizer, such as 2,2,6,6-tetramethylpiperidino-4, as disclosed in JP-B-61-56187, is disclosed. -Propyltrimethoxysilane, 2,2,6,6-tetramethylpiperidino-4-propylmethyldimethoxysilane, 2,2,6,6-tetramethylpiperidino-4-propyltriethoxysilane, 2, Examples include 2,6,6-tetramethylpiperidino-4-propylmethyldiethoxysilane, (partial) hydrolysates thereof, and the like. These light stabilizers may be used in combination of two or more.
It is preferable that the compounding quantity of a ultraviolet light stabilizer is 0.01-10 mass% with respect to solid content of a silicone coating composition. More preferably, it is 0.03-7.5 mass%.

  The silicone coating composition of the present invention can be obtained by mixing predetermined amounts of each of the above components according to a conventional method.

  The silicone coating composition thus obtained forms a film by applying and curing the silicone coating composition on at least one surface of the substrate directly or via at least one other layer. Coated articles can be obtained.

  Here, as a coating method of the silicone coating composition, it is possible to coat the substrate by a usual coating method, for example, brush coating, spraying, dipping, flow coating, roll coating, curtain coating, spin coating, knife coating. Various coating methods such as can be selected.

  The base material used here is not particularly limited, and examples thereof include plastic molded products, wood-based products, ceramics, glass, metals, or composites thereof, and various plastic materials (organic resins). Base material), especially polycarbonate, polystyrene, acrylic resin, modified acrylic resin, urethane resin, thiourethane resin, polycondensate of halogenated bisphenol A and ethylene glycol, acrylic urethane resin, halogenated aryl group-containing acrylic Resins, sulfur-containing resins and the like are preferable. Further, the surface of these resin base materials is treated, specifically, chemical conversion treatment, corona discharge treatment, plasma treatment, treatment with acid or alkaline liquid, and the base material body and the surface layer are formed of different types of resins. The laminated body currently used can also be used. Examples of laminates include laminates in which an acrylic resin layer or urethane resin layer is present on the surface layer of a polycarbonate resin substrate produced by a coextrusion method or a laminate method, or an acrylic resin layer is present in the surface layer of a polyester resin substrate. And the like.

  The silicone coating composition of the present invention is directly or as needed on the surface of the resin substrate via a primer layer, an ultraviolet absorbing layer, a printing layer, a recording layer, a heat ray shielding layer, an adhesive layer, an inorganic vapor deposition film layer, etc. It can also be formed.

  The curing after applying the silicone coating composition of the present invention may be left in the air and air-dried, or may be heated. Although the curing temperature and the curing time are not limited, it is preferable to heat at a temperature lower than the heat resistant temperature of the substrate for 10 minutes to 2 hours. Specifically, heating at 80 to 135 ° C. for 30 minutes to 2 hours is more preferable.

  The thickness of the coating film is not particularly limited and may be 0.1 to 50 μm. However, in order to satisfy the hardness of the coating film, scratch resistance, long-term stable adhesion, and generation of cracks. 1 to 20 μm is preferable.

  The composition of the present invention is one of the features of visible light transmittance when it is used as a coating film. As the index, the upper limit of the haze value of the coating film is determined. Since the haze generally increases as the film thickness increases, the haze at a film thickness of 5 μm or less is preferably 8.0 or less, preferably 5.0 or less, more preferably 2.0 or less. The haze of the coating film is a value measured with a turbidimeter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.).

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In the following examples,% indicates mass%.

<Production of Component (A) Silicone Resin>
[Production Example 1]
In a 2 L flask, 339 g (2.49 Si mol) of methyltrimethoxysilane, 56 g (0.33 Si mol) of silicate 35 (manufactured by Tama Chemical Industries, Ltd .: partial hydrolysis condensate of tetraethoxysilane, average dimer) Were mixed well. Next, after cooling so that the liquid temperature became about 10 ° C., 308 g of a 0.25N aqueous acetic acid solution was added dropwise, and hydrolysis was performed while cooling so that the internal temperature did not exceed 40 ° C. After completion of dropping, the mixture was stirred at 40 ° C. or lower for 1 hour and then at 60 ° C. for 3 hours to complete the hydrolysis.
Thereafter, 300 g of diacetone alcohol was added, and methanol and ethanol produced by hydrolysis were heated and distilled at normal pressure until the liquid temperature reached 95 ° C., and after heat condensation, t-butanol was used as a diluent. 470 g and 0.05 g of KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent were added, and filter paper filtration was performed to obtain a colorless and transparent silicone resin solution (A-1) having a nonvolatile content concentration of 19.5%. .

<Production of Component (B) Rutile Type Titanium Oxide Dispersion>
[Production Example 2]
Fine particle titanium oxide MT-100AQ (rutile type, average primary particle size 15 nm, surface treatment: aluminum hydroxide, hydrous silicic acid, sodium alginate) 50 g, ion-exchanged water 545 g, dispersant (poise 520: carboxy group) 5 g of an organic polymer-containing 40% aqueous solution (manufactured by Kao Corporation) was mixed to obtain a white slurry. 600 g of this slurry was put into a bead mill (Ultra Apex Mill UAM-015, manufactured by Kotobuki Industries Co., Ltd.) equipped with 0.05 mmφ zirconia beads, and mechanical dispersion was performed in the bead mill. After operating at a peripheral speed of 10 m / s for 2 hours, the dispersion was recovered to obtain 549 g (solid content 8.6%) of a white suspension (B-1).
When the particle size distribution of fine particle titanium oxide in this dispersion was measured with Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.), the volume average particle size D50 was 40 nm and D95 was 96 nm. The particle size distribution is shown in FIG.

[Production Example 3]
Fine particle titanium oxide MT-100AQ (rutile type, average primary particle size 15 nm, surface treatment: aluminum hydroxide, hydrous silicic acid, sodium alginate) 50 g, ion-exchanged water 545 g, dispersant (poise 532A: carboxy group) 5 g of an organic polymer-containing 40% aqueous solution (manufactured by Kao Corporation) was mixed to obtain a white slurry. 600 g of this slurry was put into a bead mill (Ultra Apex Mill UAM-015, manufactured by Kotobuki Industries Co., Ltd.) equipped with 0.05 mmφ zirconia beads, and mechanical dispersion was performed in the bead mill. After operating at a peripheral speed of 10 m / s for 2 hours, the dispersion was recovered to obtain 555 g (solid content: 8.4%) of a white suspension (B-2).
The volume average particle diameter D50 of fine particle titanium oxide in this dispersion was 39 nm, and D95 was 92 nm.

[Production Example 4]
Fine particle titanium oxide MT-05 (rutile type, average primary particle shape 10 nm, manufactured by Teika Co., Ltd., surface treatment: aluminum hydroxide, hydrous silicic acid) 50 g, ion-exchanged water 545 g, dispersant (poise 521 manufactured by Kao Corporation) 5 g of a carboxyl group-containing organic polymer 40% aqueous solution) was mixed to obtain a white slurry. 600 g of this slurry was put into a bead mill (Ultra Apex Mill UAM-015, manufactured by Kotobuki Industries Co., Ltd.) equipped with 0.05 mmφ zirconia beads, and mechanical dispersion was performed in the bead mill. After operating at a peripheral speed of 10 m / s for 2 hours, the dispersion was recovered to obtain 559 g (solid content 8.2%) of a white suspension (B-3).
The volume average particle diameter D50 of fine particle titanium oxide in this dispersion was 90 nm, and D95 was 311 nm.

[Production Example 5]
Fine particle titanium oxide STR-100W-H (manufactured by Sakai Chemical Co., Ltd. Rutile type, average primary particle shape 20 nm, surface treatment: silica, polyglycerin) 50 g, ion-exchanged water 545 g, dispersant (poise 521: carboxyl group-containing organic polymer) A white slurry was obtained by mixing 5 g of a 40% aqueous solution, manufactured by Kao Corporation. 600 g of this slurry was put into a bead mill (Ultra Apex Mill UAM-015, manufactured by Kotobuki Industries Co., Ltd.) equipped with 0.05 mmφ zirconia beads, and mechanical dispersion was performed in the bead mill. After the operation at a peripheral speed of 10 m / s for 2 hours, the dispersion was recovered to obtain 578 g (solid content: 8.3%) of a white suspension (B-4).
The volume average particle diameter D50 of fine particle titanium oxide in this dispersion was 47 nm, and D95 was 116 nm.

[Production Example 6]
Fine particle titanium oxide MT-100AQ (rutile type, average primary particle size 15 nm, surface treatment: aluminum hydroxide, hydrous silicic acid, sodium alginate) 50 g, ion-exchanged water 545 g, dispersant Disperbyk-190 (manufactured by BYK) ) 5 g was mixed to obtain a white slurry. 600 g of this slurry was put into a bead mill (Ultra Apex Mill UAM-015, manufactured by Kotobuki Industries Co., Ltd.) equipped with 0.05 mmφ zirconia beads, and mechanical dispersion was performed in the bead mill. After operating at a peripheral speed of 10 m / s for 2 hours, the dispersion was recovered to obtain 597 g of a white suspension (B-5) (solid content: 8.3%).
The volume average particle diameter D50 of the fine particle titanium oxide in this dispersion was 42 nm, and D95 was 106 nm.

[Production Example 7]
The titanium oxide powder slurry mixed in the same composition as in Production Example 2 is not subjected to bead mill pulverization, but is stirred by mechanical stirring for 1 minute to obtain 600 g of dispersion (B-6) (solid content: 8.4%). It was.
This dispersion had a volume average particle diameter D50 of 230 nm and D95 of 2.24 μm.
The titanium oxide dispersions prepared in Production Examples 2 to 7 are summarized in Table 1.

<Production of component (A) silicone resin in the presence of component (B) dispersion>
[Production Example 8]
A 2 L flask was charged with 209 g (1.54 Si mol) of methyltrimethoxysilane, cooled to a liquid temperature of about 10 ° C., and then prepared in 20 g of 0.25N acetic acid aqueous solution, 88 g of ion-exchanged water, and Production Example 2. 35 g of titanium oxide dispersion (B-1) and 63 g of water-dispersed silica sol “Snowtex O” (manufactured by Nissan Chemical Industries, Ltd.) are added dropwise, and hydrolysis is performed while cooling so that the internal temperature does not exceed 40 ° C. It was. After completion of dropping, the mixture was stirred at 40 ° C. or lower for 1 hour and then at 60 ° C. for 3 hours to complete the hydrolysis. Thereafter, 186 g of propylene glycol monomethyl ether acetate was added, and methanol produced by hydrolysis was heated and distilled at normal pressure until the liquid temperature reached 85 ° C., and after heat condensation, t-butanol was used as a diluent. 247 g and 0.3 g of KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent were added, filtered through a filter paper, and a white suspended titanium oxide-containing silicone resin solution (AB-) having a nonvolatile content of 19.1% 1) 662 g was obtained.

[Production Example 9]
In a 2 L flask, 209 g (1.54 Si mol) of methyltrimethoxysilane was charged and cooled to 10 ° C. or lower, and then 63 g of a water-dispersed silica sol “Snowtex O” (manufactured by Nissan Chemical Industries, Ltd.), a titanium oxide dispersion ( B-2) 36 g and 107 g of ion-exchanged water were added, and hydrolysis was performed at 10 ° C. or lower for 3 hours. Subsequently, the mixture was stirred at 60 ° C. for 3 hours to complete the hydrolysis. Thereafter, 186 g of cyclohexanone was added, and methanol produced by hydrolysis was distilled off by heating until the liquid temperature reached 85 ° C. at normal pressure, and after heat condensation, 247 g of isopropanol as a diluent and KP as a leveling agent. -341 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred well, followed by filtration with filter paper. A white suspended titanium oxide-containing silicone resin solution (AB-) having a non-volatile concentration of 17.7% 2) 620 g was obtained.

[Production Examples 10 to 13]
The same procedure as in Production Example 9 was performed except that the type and amount of the titanium oxide dispersion, the amount of ion exchange water to be added, and the amount of aqueous acetic acid solution were changed as shown in Table 2, and the white suspended titanium oxide-containing silicone was obtained. Resin solutions (AB-3) to (AB-6) were obtained.

<Preparation of silicone coating composition, evaluation of cured coating film>
[Example 1]
With respect to the titanium oxide-containing silicone resin solution (AB-1) obtained in Production Example 8, a 0.25% aqueous solution of tetrabutylammonium hydroxide (TBAH) as a curing catalyst with respect to (AB-1) solution state A coating composition (1) was obtained by adding and mixing 10%.
This composition was flow-coated on a quartz substrate and then heat-cured at 120 ° C. for 10 minutes to obtain a thin film having a thickness of 3 μm. FIG. 2 shows the result of measuring the light absorption spectrum of this thin film with an ultraviolet-visible spectrophotometer. It was confirmed that light of 300 nm or less was absorbed and that transparency was ensured in the visible range.
This coating composition was flow-coated on a primer layer of a polycarbonate substrate with a primer layer (formed from acrylic primer PC-7A (manufactured by Shin-Etsu Chemical Co., Ltd.)) and cured at 130 ° C. for 1 hour. The following evaluation was performed on the obtained coating film, and the results are shown in Table 3.

[Examples 2-6, Comparative Examples 1-3]
A coating composition was prepared by mixing each component in the ratio shown in Table 3. In Comparative Example 2, a commercially available anatase-type titanium oxide sol (trade name: OPTRAIQUE 1130Z (solid content: 30%, methanol dispersion manufactured by Catalyst Kasei Kogyo Co., Ltd.) was used as a comparison of component (B). The catalyst is shown below: Since component (D) is an organic solvent already contained in components (A) to (C), it is not specified.
As in Example 1, this coating composition was applied to a polycarbonate substrate with a primer layer and cured at 130 ° C. for 1 hour. The following evaluation was performed on the obtained coating film, and the results are shown in Table 3.

<Compound of component (C)>
Al (acac) ₃ : Tris (acetylacetonate) aluminum TBAH: 0.25% aqueous solution of tetrabutylammonium hydroxide TPAH: 0.25% aqueous solution of tetra n-propylammonium hydroxide

Evaluation method of cured film << coating film transparency >>
The haze of the coating film was evaluated according to the following criteria based on the value (H) measured with a haze meter (NDH2000 Nippon Denshoku Industries Co., Ltd.).
○: H ≦ 3.0
Δ: 3.0 <H <8.0
X: H ≧ 8.0

《Abrasion resistance》
In accordance with ASTM 1044, a wear wheel CS-10F was mounted with a Taber abrasion tester, the haze value after 500 rotations under a load of 500 g was measured, and the haze difference (ΔH) before and after the test was measured. The scratch resistance was evaluated according to the following criteria.
○: ΔH ≦ 5.0
Δ: 5.0 <ΔH <10.0
×: ΔH ≧ 10.0

《Adhesion》
In accordance with JIS K5400, using a razor blade, make 25 grids by making 6 vertical and horizontal cuts at 2 mm intervals on the coating film, and after attaching cello tape (manufactured by Nichiban Co., Ltd.) well The number of squares (X) remaining when the coating film was not peeled off suddenly in the 90 ° front direction was expressed as X / 25.

《Weather resistance evaluation》
Using I-Super UV Tester W-151 manufactured by Iwasaki Electric Co., Ltd., [Black panel temperature 63 ° C, humidity 50% RH, illuminance 50 mW / cm ² , rain 10 seconds / 1 hour 5 hours] → [Black panel temperature The test was conducted for 100 hours and 250 hours under the conditions of repeating this cycle, with 1 cycle at 30 ° C. and 95% RH as one cycle. Before and after the weather resistance test, in accordance with JIS K7103, the degree of yellowing, the weather resistance coating cracking property, and the weather coating release state were observed visually or under a microscope (250 times magnification) according to the following evaluation criteria.

<Weather-resistant coating cracking properties>
The appearance of the coating film after the weather resistance test was evaluated according to the following criteria.
○: No abnormality △: Slightly cracked ×: Cracks in the entire coating film

It is a figure which shows the particle size distribution of the fine particle titanium oxide in a dispersion liquid (B-1). It is an ultraviolet-visible absorption spectrum figure of the coating film of coating composition (1).

Claims (8)

(A) The following general formula (1):
(R ¹ ) _m (R ² ) _n Si (OR ³ ) _4-mn (1)
Wherein R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ³ is an alkyl group having 1 to ³ carbon atoms, and m and n are each independently 0 or 1 and m + n is 0, 1 or 2.)
A silicone resin obtained by (co) hydrolysis / condensation of at least one selected from alkoxysilanes represented by the following and partial hydrolysis-condensation products thereof,
(B) A rutile-type titanium oxide fine particle dispersion containing a dispersant having an average particle diameter (volume average particle diameter D50) of 0.2 μm or less measured by a dynamic light scattering method,
(C) a curing catalyst,
(D) The silicone coating composition which contains a solvent and (B) titanium oxide solid content is 0.1-15 mass% with respect to the total amount of solids in a composition.   2. The silicone coating composition according to claim 1, wherein the rutile titanium oxide used for component (B) is surface-treated with a compound containing one or more elements selected from silicon, aluminum and zirconium.   The dispersion liquid of component (B) is prepared by pulverizing agglomeration of rutile titanium oxide powder in a dispersion medium in the presence of a dispersant. Silicone coating composition.   The dispersant used for component (B) is an organic polymer containing one or more substituents selected from a carboxyl group, a phosphate group, and a salt thereof. Silicone coating composition.   The 95% volume particle diameter (D95) measured by the dynamic light scattering method of the titanium oxide particles in the dispersion liquid of the component (B) is 0.5 μm or less. The silicone coating composition according to claim 1.   Furthermore, (E) Colloidal silica is included, The silicone coating composition of any one of Claims 1-5 characterized by the above-mentioned. (I) A step of preparing a dispersion of component (B) by mixing a dispersion medium, a dispersant and rutile-type titanium oxide powder, and pulverizing and dispersing with a bead mill;
(II) The following general formula (1):
(R ¹ ) _m (R ² ) _n Si (OR ³ ) _4-mn (1)
Wherein R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ³ is an alkyl group having 1 to ³ carbon atoms, and m and n are each independently 0 or 1 and m + n is 0, 1 or 2.)
Hydrolysis condensation is performed by adding a water-containing liquid containing the component (B) produced in the step (I) to at least one selected from the alkoxysilanes represented by the formula (1) and the partial hydrolysis-condensation product thereof. The manufacturing method of the silicone coating composition characterized by including the process of manufacturing the silicone resin of (A).   A coated article obtained by coating the cured film of the silicone coating composition according to any one of claims 1 to 6 on at least one surface of a substrate directly or via at least one other layer.