JP2001131481A - Inorganic coating composition and method for forming coating film thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic coating composition curable at a temperature as low as 150 deg.C or below, undecomposable by an oxidative effect by photoexitation, capable of forming a coating film excellent in stainproof properties, adhesion to a substrate, solvent resistance, abrasion resistance, thick film coating properties and the like and useful as a binder or a primer thereof for fixing titanium oxide exhibiting a photocatalytic effect. SOLUTION: The inorganic coating composition comprises (A) a polyorganosiloxane having a recurring structural unit represented by the formula: RaSiO(4-a)/2 (wherein R is a hydrocarbyl group; and a is 0.8-1.8) and at least 1 wt% of a hydroxyl group bonded to a silicon atom, (B) a hydrolyzable organic silane compound represented by the formula: R'bSiX(4-b) (wherein R' is a 1-8C hydrocarbyl group; b is 0-3; and X is a hydrolyzable group) and (C) an organic acid tertiary ammonium salt, the amount of the component C being 0.05-10 pts. wt. based on 100 pts. wt. of the total of the solids content of the components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes a photocatalytic action which is effective in preventing contamination of the surface of a substrate such as plastic, organic coating, metal, wood and the like and which forms a coating having excellent durability. The present invention relates to an inorganic coating composition and a method for forming a coating film thereof.

[0002]

2. Description of the Related Art Electrons are accumulated in a conduction band by irradiating a titanium oxide having a photocatalytic action with an actinic ray having a wavelength having energy equal to or greater than a band cap.
Holes are generated in the valence band. It is already known that organic substances are decomposed by electrons generated by this photoexcitation, strong oxidizing action generated by holes, and the like.
It has already been proposed to use such a photocatalytic action of titanium oxide for antifouling, antibacterial, air purification, water purification and the like.

As a method for immobilizing titanium oxide fine particles on the surface of the above-mentioned base material, for example, a method of mixing and dispersing in a binder which is hardly decomposed by strong oxidizing action and dispersing the same to a target base material It is known to paint surfaces. However, if the substrate is a plastic or organic coating, to avoid these thermal decomposition and thermal deformation,
It must be cured at a low temperature of 150 ° C. or less, preferably 120 ° C. or less, and have good adhesion to the substrate surface, and it is necessary to use a binder that sufficiently satisfies these conditions. . In order to maintain the durability of the plastic substrate, it is necessary to take measures to prevent the photocatalytic action of titanium oxide from affecting the plastic. In addition, in order to apply to a coating film formed on an automobile outer panel (including plastic), it is strongly required to ensure long-term durability. Therefore, it is not suitable to use an organic resin that may be photodegraded as a binder for fixing titanium oxide, and a hardly decomposable inorganic material is used.

[0004] It has also been proposed to form a barrier layer with a hardly decomposable binder and apply a composition containing titanium oxide on the surface of the barrier layer.

As the inorganic binder, for example, the use of a hydrolyzable product of an organometallic compound is disclosed in JP-A-4-174679, JP-A-8-141503, JP-A-8-164334, JP-A-9-40
No. 872, Japanese Patent Application Laid-Open No. 9-248467, Japanese Patent No. 2756474, and the like, in which an organic silane compound, an organic titanium compound and the like are described as the organic metal compound. When these compounds are applied to the cured coating surface of an acrylic resin / melamine resin, polyester resin / melamine resin, for example, the adhesion, solvent resistance, and abrasion resistance of the four-functional compound are good, When applied to a thick film, the coating film tends to crack, trifunctional and
The functional compound has a defect that adhesion to the cured coating surface is not sufficient.

When a film is formed at a low temperature of 150 ° C. or less by a sol-gel method using an organic silane compound, the film becomes honeycomb-like porous and lacks denseness. Therefore, this is used as a binder or primer for titanium oxide.
When used as, the photooxidation effect of titanium oxide reaches the base material of the lower layer, and discoloration and chalking occur in outdoor exposure for several months, so that it is difficult to use as a binder and a primer. there were.

A titanium alkoxide is usually used as an organic titanium compound.
When applied to the cured coating surface of melamine resin, polyester resin and melamine resin, the adhesion between the two coatings is not sufficient, and the refractive index is large, resulting in poor gloss and interference pattern. Have.

It is also known to use a polyorganosiloxane as a binder (Japanese Patent Laid-Open No.
171408), which form a dense continuous film, but have insufficient adhesion to the organic film, and
Poor curability at a low temperature of 150 ° C. or lower causes defects such as poor solvent resistance and chemical resistance of the coating film.

A composition containing a polyorganosiloxane and a hydrolyzable trifunctional organic silane compound has also been proposed (JP-A-5-140507). Adhesion, low-temperature curability, long-term durability, weather resistance, and the like are inferior.

[0010]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention relates to a binder for immobilizing titanium oxide having a photocatalytic action or a primer thereof. In particular,
It cures at a low temperature of 150 ° C or less, and is not decomposed by strong oxidizing action due to light excitation, has excellent anti-staining properties, excellent adhesion to substrates, solvent resistance, abrasion resistance, thick film paintability, etc. It is an object of the present invention to provide an inorganic coating composition which forms an excellent coating film, and a method for forming a coating film having excellent stain resistance using the same.

That is, the present invention provides (A) a repeating unit represented by the following general formula (1) wherein R is a monovalent substituted or unsubstituted hydrocarbon group, and a is 0.8 to 18. A polyorganosiloxane having a structural unit and having 1% by weight or more of a hydroxyl group bonded to a silicon atom, (B) a compound represented by the following general formula (2), wherein R ′ is the same or different, monovalent substituted or unsubstituted A hydrocarbon group having 1 to 8 carbon atoms, b is an integer of 0 to 3, X is a hydrolyzable group], and (C) a quaternary ammonium salt of an organic acid. And the ratio of the component (C) is 0.0% per 100 parts by weight of the total solid content of the component (A) and the component (B).
It relates to an inorganic coating composition (1), which is 5 to 10 parts by weight.

General formula (1): RaSiO (4-a) / 2 General formula (2): R′bSIX (4-b) The present invention also provides a titanium oxide having a photocatalytic action, particularly preferably hydration. Hydrogen peroxide is added to the titanium oxide gel or sol to dissolve the hydrated titanium oxide,
A composite compound colloid of rutile-type titanium oxide and tin oxide obtained by adding a tin compound at a ratio of O2 / SnO2 = 1.5 to 14 (solids weight ratio) and heating is mixed with the inorganic coating composition (1). )) And an inorganic coating composition (2).

[0013] The present invention also relates to a method for coating a substrate with an inorganic coating composition (2) to prevent contamination of the substrate surface.

The present invention also relates to a method of coating an inorganic coating composition (1) on a substrate, forming a primer coating film on the base material, and coating the inorganic coating composition (2) on the coated surface. The present invention relates to a method for preventing contamination of a material surface.

The present invention also provides a method of forming a coating of the inorganic coating composition (1) on the surface of a substrate,
(C) A coating composition (3) containing a hydrolyzable organic silane compound represented by the general formula (2) or a hydrolyzate thereof, and a titanium oxide sol or the above-mentioned composite colloid, and the surface of the substrate is coated. And methods for preventing contamination.

The present invention will be described in more detail.

Component (A): The following general formula (1)
Is a monovalent substituted or unsubstituted hydrocarbon group, and a is 0.8 to
1.8] and having at least 1% by weight of a hydroxyl group bonded to a silicon atom.

General formula (1): RaSiO (4-a) / 2 The component (A) is preferably resinous from the viewpoint of film-forming properties. R in the general formula (1) of the polyorganosiloxane is an organic group having 1 to 8 carbon atoms, for example, an alkyl group such as methyl, ethyl and propyl group, an aryl group such as phenyl group, and a chloromethyl group. And the like. A in the general formula (1)
Is preferably in the range of 0.8 to 1.8, particularly 1.0 to 1.6. If it is less than 0.8, the storage stability of the inorganic coating composition (1) is reduced, and viscosity increases and gelation is likely to occur during storage. If it is more than 1.8, the curing speed of the coating film becomes slow,
The curability of the formed coating film is poor, and the solvent resistance is not sufficient, which is not preferable.

The component (A) has a number average molecular weight of 1,000.
-30,000, especially 3000-20000, and the hydroxyl group content is preferably 1% by weight or more, particularly preferably 3-10% by weight.

Component (B): The following general formula (2):
'Is the same or different monovalent substituted or unsubstituted carbon atom
8 hydrocarbon groups, b is an integer of 0 to 3, and X is a hydrolyzable group].

R ′ in the general formula (2) of the general formula (2): R′bSix (4-b) organosilane compound is the same or different, substituted or unsubstituted monovalent monovalent having 1 to 8 carbon atoms. A hydrocarbon group, for example, an alkyl group such as methyl, ethyl, propyl, and butyl;
, A cycloalkyl group such as cyclopentyl and cyclohexyl, a vinyl group, a chloromethyl group, a γ-chloropropyl group, a 3,3,3-trifluoropropyl group, a γ-methacryloxypropyl group, and a γ-glycidoxypropyl group , A mercaptopropyl group, a 3,4-epoxycyclohexylmethyl group, a γ-aminopropyl group and the like. X in the general formula (2) is a hydrolyzable group, for example,
Examples thereof include an alkoxy group, an acetoxy group, an oxime group, and an aminoxy group, and an easily available alkoxy group is preferable.

The organic silane compound represented by the general formula (2) is a monofunctional, difunctional, trifunctional, or tetrafunctional alkoxysilane compound in which b is an integer of 0 to 3. Among them, the compounds of b = 0 include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like, and the compounds of b = 1 include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyl Triethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltrimethyl Kishishiran, .gamma.-aminopropyltriethoxysilane, phenyltrimethoxysilane, phenyl triethoxysilane, b = 2
Dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glidoxypropylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane , Γ-methacryloxypropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, etc., as a compound of b = 3, trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropylpropoxysilane, Dimethylisobutylmethoxysilane and the like can each be exemplified.

Of these, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-gly Sidoxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycoxypropylmethyldiethoxysilane Silane and the like are preferred. These can be used alone or in combination of two or more.

The ratio of the component (A) to the component (B) can be appropriately selected depending on the purpose. However, the ratio of the component (B) to the equivalent of 1 equivalent of the hydroxyl group in the polyorganosiloxane of the component (A) is 0.2%. It is preferably in the range of 10 to 10 equivalents, particularly 0.5 to 3.0 equivalents.

Component (C): a quaternary ammonium salt of an organic acid, which is obtained by a neutralization reaction between a quaternary ammonium hydroxide and an organic acid.

As the quaternary ammonium hydroxide, for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydroxide, tetra-n-hexylammonium hydroxide, Benzyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide and the like can be used.

As organic acids, carboxylic acid compounds and sulfonic acid compounds can be used. Examples of the carboxylic acid compound include formic acid, acetic acid, propionic acid, n-hexanoic acid, aliphatic monocarboxylic acids such as n-octanoic acid, acetic anhydride, oxalic acid, malonic acid, succinic acid, glutaric acid,
Aliphatic dicarboxylic acids such as maleic acid, aliphatic tricarboxylic acids such as citric acid, aromatic monocarboxylic acids such as benzoic acid, ethylbenzoic acid, dimethylbenzoic acid, toluic acid, cumic acid, phthalic acid, phthalic anhydride, isophthalic acid Examples include aromatic dicarboxylic acids such as acid, terephthalic acid, phthalic dichloride, and phthalamide; aromatic tricarboxylic acids such as trimellitic acid; and tetracarboxylic acids such as pyromellitic acid. As the sulfonic acid compound, for example, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, ethylenesulfonic acid, propenesulfonic acid, methanedisulfonic acid, ethanedisulfonic acid, propanedisulfonic acid , Aliphatic sulfonic acids such as isethionic acid and eosinic acid, benzenesulfonic acid, (O- or m
Benzenesulfonic acids such as-or p-) toluenesulfonic acid, (O- or m-) xylene-4-sulfonic acid, (O- or m- or p-) chlorobenzenesulfonic acid,
(O- or m- or p-) sulfobenzoic acid, sulfoacetic acid and other sulfocarboxylic acids, phenol (2 or 3 or 4) sulfonic acid, 2-nitrophenol-4-sulfonic acid, 5-sulfosalicylic acid and the like And aromatic sulfonic acids such as oxysulfonic acid.

In the neutralization reaction, the ratio of the quaternary ammonium hydroxide to the organic acid is 1.0 to 5.0 with respect to 1 mole equivalent of the quaternary ammonium hydroxide.
Moles, especially in the range of 1.5 to 3.0 molar equivalents.

The amount of the component (C) is 0.00.0 parts by weight per 100 parts by weight of the total solid content of the components (A) and (B).
5 to 10 parts by weight, especially 0.1 to 5 parts by weight, are suitable.
If the amount of the component (C) is less than 0.05 part by weight, the curability of the composition is reduced. If the amount is more than 10 parts by weight, the adhesion to the substrate surface is undesirably reduced.

The inorganic coating composition (1) contains the components (A), (B) and (C) described above, and these are mixed with an ordinary organic solvent for coating and dissolved or dispersed. Can be prepared.

The inorganic coating composition (1) may further contain, in addition to the above components, coating pigments such as coloring pigments, metallic pigments, light interference pigments, extender pigments, organic solvents, metal chelate compounds, metal alkoxides. , Amines, organic metal salts, organic acids, their anhydrides, Lewis acids, catalysts such as metal halide compounds, thickeners, defoamers, leveling agents, anti-penetrating agents, ultraviolet absorbers, light stabilizers, pH A preparation agent and the like can be appropriately compounded as needed.

The inorganic coating composition (1) can be coated by a usual method, for example, by various means such as brush coating, spray coating, dip coating, flow coating, roll coating and the like. Can be painted. The coating thickness of the cured coating film is preferably in the range of 0.001 to 30 μm, particularly preferably 0.05 to 5 μm. The drying and curing temperature of the coating film is 50-15
0 ° C, particularly preferably 80 to 120 ° C, is preferred. If the drying and curing temperature of the coating film is at this level, the plastic or organic coating film hardly deteriorates or deforms. The glass transition temperature of the formed cured coating film is preferably from 50 to 130 ° C.

Examples of the substrate (substrate) for coating the inorganic coating composition (1) include plastic, iron, non-ferrous metal, glass, ceramic, fiber, wood, and an organic coating film coated on the surface thereof. And so on. this house,
Examples of the plastic include polycarbonate, acrylic resin, polystyrene, ABS resin, polyurethane resin, polyolefin resin, cellulose resin, vinyl chloride resin, polyester resin, and unsaturated polyester resin. Specific examples include the body and parts of automobiles formed using these materials, the outer panels of mechanical products, and electric products.

The inorganic coating composition (1) can be applied to the surface of the above-mentioned substrate, and the coating film is cured at a low temperature of 150 ° C. or less without being affected by humidity. Excellent in adhesion, durability, weather resistance, etc.

The inorganic coating composition (2) in the present invention
Is obtained by adding hydrogen peroxide to a titanium oxide having a photocatalytic action, particularly preferably a gel or sol of hydrated titanium oxide, to dissolve the hydrated titanium oxide in the inorganic coating composition (1), TiO2 / SnO2 = 1.5-14
This is a composition containing a “composite colloid” of rutile-type titanium oxide and tin oxide obtained by adding a tin compound at a ratio of (solid content weight ratio) and heating.

Titanium oxide used in the preparation of the composite colloid includes an anatase type and a rutile type. The former has a strong photocatalytic action, but is insufficient in practicality due to insufficient durability of the coating film. Poor, on the other hand, the photocatalytic action of the rutile type is slightly inferior to that of the anatase type, but the durability of the coating film is excellent, and it has a sufficient organic substance resolution for preventing contamination. Can be used.

The composite colloid is prepared by adding hydrogen peroxide to a hydrated titanium oxide gel or sol to dissolve the hydrated titanium oxide,
This is a composite colloid of rutile-type titanium oxide and tin oxide obtained by adding a tin compound at a ratio of TiO2 / SnO2 = 1.5 to 14 (solid weight ratio) and heating.

The gel of hydrated titanium oxide is obtained by adding an alkali to an aqueous solution of a titanium salt such as titanium chloride or titanium sulfate, neutralizing the resultant, and washing the resultant. The sol of hydrated titanium oxide can be obtained by passing an aqueous solution of a titanium salt through an ion-exchange resin to remove anions or hydrolyzing a titanium alkoxide. As the tin compound, for example, tin salts such as tin chloride and tin nitrate, oxides of tin, hydroxides and the like can be used. The amount of the tin compound used is TiO ₂ / SnO ₂ = 1.5 to 14, especially 2
It is preferably in the range of 10 to 10 (weight ratio of solid content). After the addition of the tin compound, the mixture is heated to a temperature of 60 ° C. or higher, preferably 80 ° C. or higher, whereby the hydrolysis proceeds, and a desired composite colloid of rutile-type titanium oxide and tin oxide is obtained. In addition, in the preparation of this composite colloid, the stability of the obtained composite colloid is improved by heating and hydrolyzing in the presence of a silicon compound.
As the silicon compound, for example, an alkali metal silicate,
Alternatively, a silicic acid solution obtained by dealkalizing an aqueous alkali metal silicate solution, silica gel, silica sol, or the like can be used. The amount of the silicon compound used is suitably in the range of 5 to 20 parts by weight per 100 parts by weight of the total solid content of the titanium oxide and the tin compound.

The composite colloid thus obtained is a composite colloid of rutile-type titanium oxide and tin oxide, or a composite colloid of rutile-type titanium oxide, tin oxide and silicon oxide. Particle size is 5
Preferably it is in the range of 100 nm. Further, the particle surface of the composite colloid is silica, silica-alumina,
By coating with silica-zirconia or the like, the weather resistance of the formed coating film can be further improved.

In the inorganic coating composition (2), the compounding amount of the composite colloid is 20 to 3 per 100 parts by weight of the total solid content of the components (A), (B) and (C).
00 parts by weight, especially in the range of 50 to 200 parts by weight, is suitable. In addition to the above components, the inorganic coating composition (2) further includes coloring pigments, metallic pigments, light interference pigments, coating pigments such as extender pigments, organic solvents, metal chelate compounds, metal alkoxides, and amines. , Organometallic salts,
If necessary, catalysts such as organic acids, anhydrides, Lewis acids, metal halide compounds, thickeners, defoamers, leveling agents, anti-bake agents, ultraviolet absorbers, light stabilizers, pH adjusters, etc. They can be appropriately blended.

In the present invention, the following method can be mentioned as a method for preventing contamination of the substrate.

Antifouling method (1): An inorganic coating composition (2) is applied to a substrate to form a coating containing titanium oxide having a photocatalytic action, particularly preferably a "composite colloid", on the surface of the substrate. I do.

Stain prevention method (2): A base material is coated with the inorganic coating composition (1) to form a primer coating film, and the coating surface is coated with the inorganic coating composition (2), and the surface of the uppermost layer is coated. A coating film containing titanium oxide having photocatalytic action, particularly preferably "composite colloid" is formed.

Staining prevention method (3): A base material is coated with an inorganic coating composition (1) to form a primer coating film, and the coated surface is coated with a hydrolyzable organic compound represented by the general formula (2). Coating composition (3) containing silane compound (B) or its hydrolysis product and titanium oxide sol or composite colloid sol
To form a coating film containing a photocatalytic titanium oxide, particularly preferably a “composite colloid”, on the uppermost layer surface.

In the method (1) for preventing contamination, a substrate is coated with an inorganic coating composition (2), and a coating containing titanium oxide having photocatalytic activity, particularly preferably a "composite colloid", is coated on the surface of the substrate. It is a method of forming.

As the substrate and the inorganic coating composition (2) in this method (1), those selected from the above-mentioned ones can be suitably used. And the inorganic coating composition (2) can be applied by a usual method.
It can be applied by means such as brush coating, spray coating, dip coating, flow coating, roll coating, etc. The coating thickness is 0.001 to 30 μm, particularly 0.05 ~
It is preferably within the range of 5 μm. The drying and curing temperature of the coating film
50-150 ° C, particularly preferably 80-120 ° C. If the drying and curing temperature of the coating film is at this level, the plastic or organic coating film hardly deteriorates or deforms. The glass transition temperature of the formed cured coating film is preferably from 50 to 130 ° C.

In the method (2) for preventing contamination, the base material is coated with the inorganic coating composition (1) to form a primer coating film, and the coated surface is coated with the inorganic coating composition (2), and the surface of the uppermost layer is coated. This is a method for forming a coating film containing a photocatalytic titanium oxide, particularly preferably a "composite colloid".

As the substrate, the inorganic coating composition (1), and the inorganic coating composition (2) in the method (2), those described above can be suitably used.

The coating of the inorganic coating composition (1) on the substrate can be carried out, for example, by a method such as brush coating, spray coating, dip coating, flow coating, roll coating, and the like. The coating film thickness is 0.001 to 30 μm in the cured coating film,
Particularly, the thickness is preferably in the range of 0.05 to 5 μm. The drying and curing temperature of the coating film can be from 50 to 150 ° C, especially from 80 to 120 ° C. At this level, the plastic or organic coating film is hardly deteriorated or deformed. The glass transition temperature of the formed cured coating film is preferably from 50 to 130 ° C. The inorganic coating composition (2) can be applied to a cured or uncured surface of the inorganic coating composition (1). The coating can be performed by, for example, a brush coating, a spray coating, a dip coating, a flow coating, a roll coating, or the like. Particularly, the thickness is preferably in the range of 0.05 to 5 μm. The drying and curing temperature of the coating film is 50-150 ° C,
Particularly, it can be carried out at 80 to 120 ° C. At this level, the plastic or organic coating film is hardly deteriorated or deformed. The glass transition temperature of the cured coating film formed is 5
The temperature is preferably from 0 to 130 ° C.

In the contamination prevention method (3), the base material is coated with the inorganic coating composition (1) to form a primer coating film, and the coated surface is coated with the hydrolyzable compound represented by the general formula (2). Coating composition containing organosilane compound (component B) or its hydrolysis product and titanium oxide sol or composite colloid (3)
To form a coating film containing titanium oxide having a photocatalytic action on the uppermost layer surface, particularly preferably a “composite colloid”.

As the substrate and the inorganic coating composition (1) in the method (3), those described above can be suitably used.

The coating composition (3) contains a hydrolyzable organic silane compound (component B) represented by the general formula (2) or a hydrolysis product thereof and a titanium oxide sol or a composite colloid. A composition.

The hydrolysis product in the composition (3) is
It is obtained by adding a hydrophilic organic solvent and water to the component (B) and hydrolyzing it. At this time, an inorganic or organic acid such as hydrochloric acid, acetic acid, chloroacetic acid, citric acid, formic acid, propionic acid, oxalic acid, and maleic acid can be used as a catalyst. This hydrolysis reaction can be performed at room temperature or by heating to 40 ° C. or higher. After the hydrolysis reaction, after aging at room temperature for 12 hours or more, a metal chelate compound such as aluminum acetylacetonate can be added. When heated as a coating film, these organic silane compounds and the like undergo a condensation reaction to form a crosslinked and cured coating film.

The titanium oxide sol in the composition (3) can be obtained by passing an aqueous solution of a titanium salt through an ion exchange resin to remove anions or hydrolyze a titanium alkoxide. As the composite colloid sol, those described for the inorganic coating composition (2) can be suitably used. The amount of the titanium oxide sol or composite colloid is in the range of 5 to 200 parts by weight, particularly 10 to 100 parts by weight, per 100 parts by weight of the component (B) (hydrolyzable organic silane compound) or its hydrolysis product. Inside is suitable.

The coating composition (3) contains the component (B) (hydrolyzable organic silane compound) or a hydrolysis product thereof and titanium oxide sol or composite colloid sol, and these are mixed with a conventional organic solvent for coating. And dissolving or dispersing them. Furthermore, to this, coloring pigments, metallic pigments, light interference pigments,
Paint pigments such as extenders, organic solvents, metal chelate compounds, metal alkoxides, amines, organic metal salts, organic acids, anhydrides, Lewis acids, metal halide compounds, and other catalysts, thickeners, defoamers , Leveling agent, anti-armpit agent,
An ultraviolet absorber, a light stabilizer, a pH adjuster and the like can be appropriately compounded as needed.

The coating of the inorganic coating composition (1) on the substrate can be carried out, for example, by a method such as brush coating, spray coating, dip coating, flow coating, roll coating, and the like. The coating film thickness is 0.001 to 30 μm in the cured coating film,
Particularly, the thickness is preferably in the range of 0.05 to 5 μm. The drying and curing temperature of the coating film can be from 50 to 150 ° C, especially from 80 to 120 ° C. At this level, the plastic or organic coating film is hardly deteriorated or deformed. The glass transition temperature of the formed cured coating film is preferably from 50 to 130 ° C. The coating composition (3) can be applied to a cured or uncured surface of the inorganic coating composition (1). The coating can be performed by, for example, a brush coating, a spray coating, a dip coating, a flow coating, a roll coating, or the like.
The range is preferably from 01 to 30 μm, particularly preferably from 0.05 to 5 μm. The drying and curing temperature of the coating film is 50 to 150 ° C, especially 8
It can be performed at 0 to 120 ° C. At this level, the plastic or organic coating film is hardly deteriorated or deformed. The glass transition temperature of the formed cured coating film is 50 to 1
Preferably it is 30 ° C.

[0057]

Industrial Applicability The inorganic coating composition of the present invention is a coating composition having a photocatalytic action. In particular, the inorganic coating compositions (2) and (3) are based on base materials such as plastics, organic coatings, metals and wood. When applied to the surface of the material, the contamination of the substrate surface can be prevented, and it can be used for antifouling, antibacterial, purification of air, purification of water, and the like, and its coating film has excellent durability.

The coating film made of the inorganic coating composition (1) can be cured at a low temperature of 150 ° C. or less without being affected by humidity, and has excellent adhesion and durability to the above-described base material. ing.

Since the inorganic coating composition (1) is not decomposed by the strong oxidizing action caused by the photoexcitation of titanium oxide, it is used as a binder for immobilizing titanium oxide having a photocatalytic action or a primer thereof. It is valid.

Inorganic coating compositions (1), (2), (3)
Is cured at a low temperature of 150 ° C. or less, is not decomposed by strong oxidizing action by light excitation,
It forms a coating film with excellent adhesion to the substrate, excellent solvent resistance, abrasion resistance, thick coating properties, etc., and a coating film with excellent stain resistance.

[0061]

EXAMPLES Examples and comparative examples of the present invention will be described. All parts and percentages are based on weight, and the thickness of the coating film is based on the cured coating film.

1. Examples 1 and 2 and Comparative Examples 1 to 3 Example 1 378 parts of a phenylmethyl-type polyorganosiloxane having a hydroxyl group content of 4.5% and a number average molecular weight of 2000,
59 parts of methyltriethoxysilane, 252 parts of xylene,
291 parts of n-butyl alcohol, isopropyl alcohol
Of the curing catalyst (c-1) (Note 1) was uniformly mixed and dissolved to obtain an inorganic coating composition (1-1). Solid content 40% (Note 2), viscosity 87 mP
a · s (Note 3). Curing catalyst (c-1): obtained by mixing 1 molar equivalent of tetramethylammonium hydroxide with 2 molar equivalents of acetic acid. Solid content: The residual solid content after heating the sample at 100 ° C. for 30 minutes. Viscosity: Measured with a B-type viscometer at a rotation speed of 60 rpm.

Example 2 378 parts of a phenylmethyl-type polyorganosiloxane having a hydroxyl group content of 4.5% and a number average molecular weight of 2000,
66 parts of γ-mercaptopropyltrimethoxysilane, 252 parts of xylene, 298 parts of n-butyl alcohol, 116 parts of isopropyl alcohol, and 0.666 part of curing catalyst (c-2) (Note 4) are uniformly mixed and dissolved. As a result, an inorganic coating composition (1-2) was obtained. The solid content is 40% (Note 2) and the viscosity is 95 mPa · s (Note 3). (Note 4) Curing catalyst (c-2): obtained by mixing 1 molar equivalent of tetramethylammonium hydroxide and 1.5 molar equivalents of acetic acid.

Comparative Example 1 378 parts of a phenylmethyl-type polyorganosiloxane having a hydroxyl group content of 4.5% and a number average molecular weight of 2,000,
252 parts of xylene, 228 parts of n-butyl alcohol, 86 parts of isopropyl alcohol, and 0.567 parts of a curing catalyst (c-1) (Note 1) are uniformly mixed and dissolved to prepare an inorganic coating composition (1-3). ) Got. The solid content is 40% (Note 2) and the viscosity is 98 mPa · s (Note 3).

Comparative Example 2 378 parts of a phenylmethyl-type polyorganosiloxane having a hydroxyl group content of 4.5% and a number average molecular weight of 2000,
59 parts of methyltriethoxysilane, 252 parts of xylene,
291 parts of n-butyl alcohol, isopropyl alcohol
113 parts and 0.656 part of a curing catalyst (c-3) (Note 5) were uniformly mixed and dissolved to obtain an inorganic coating composition (1-4). Solid content 40% (Note 2), viscosity 87 mP
a · s (Note 3). Curing catalyst (c-3): obtained by mixing 1 molar equivalent of tetramethylammonium hydroxide with 2 molar equivalents of hydrochloric acid.

Comparative Example 3 378 parts of a phenylmethyl type polyorganosiloxane having a hydroxyl group content of 4.5% and a number average molecular weight of 2,000,
59 parts of methyltriethoxysilane, 252 parts of xylene,
291 parts of n-butyl alcohol, isopropyl alcohol
113 parts of dibutyltin diacetate and 0.656 parts of dibutyltin diacetate were uniformly mixed and dissolved to obtain an inorganic coating composition (1-5). Solid content 40% (Note 2), viscosity 87 mPa
・ It is s (Note 3).

2. Performance Test Results A coating film performance test was performed on the compositions obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

A cold-rolled steel sheet having a thickness of 0.7 mm is subjected to a chemical conversion treatment, a cationic electrodeposition coating, and an intermediate coating, and is further coated with an acrylic / melamine resin-based black paint (“Magiclon”, manufactured by Kansai Paint Co., Ltd., trade name). The coating was applied to a film thickness of 15 μm and cured by heating at 140 ° C. for 30 minutes.

Next, the compositions obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were diluted with isobutanol to obtain a solid content of 2%.
The solution adjusted to 0% was coated on the black painted surface with a film thickness of 3 to 5%.
It was coated to a thickness of μm and dried by heating at 100 ° C. for 30 minutes. Various performance tests were performed on the coated plate thus obtained. The results are shown in Table 1. The test method is as follows.

Coated surface condition: The coated surface was visually observed. ○ indicates that the gloss is good and no abnormality is observed in appearance, △ indicates that the gloss is slightly inferior, and cracks are slightly observed, and X indicates that many shiny cracks and cracks are observed.

Adhesion: 100 pieces of 1 mm × 1 mm Gobang were cut with a cutter so as to reach the base material, an adhesive cellophane tape was adhered to the coated surface, and the Gobang after rapidly peeling it off at 20 ° C. The number of remaining eye coats was examined.は indicates 100 remaining, △ indicates 99 to 80, and X indicates 79 or less.

Solvent resistance: Gauze added to isopropyl alcohol
The coated surface was visually observed after wiping 20 times back and forth while strongly pressing the coated surface with a finger.
○ indicates that no abnormality was observed, △ indicates that scratches and shine were observed, and × indicates that the coating film was melted off and dropped off.

Hardness: The hardness was measured at 20 ° C. using a micro hardness tester [Micro Hardness Tester FM, trade name, manufactured by Feature Tech Co., Ltd.]. The higher the value, the harder it is.

[0074]

[Table 1]

3. Preparation of sample 3-1) Hydrolyzate of organosilane compound (a) 460 parts of isopropyl alcohol was placed in a 2-liter four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a dropping funnel. 186 parts of tetraethoxysilane and 192 parts of γ-glycidoxypropyltrimethoxysilane are added, and while stirring, a 0.01 N hydrochloric acid aqueous solution 10 is added.
After dropping 8 parts, the mixture was heated for 1 hour while maintaining the liquid temperature at 60 ° C., and then aluminum acetylacetonate 7.5 was added.
The mixture was heated at 60 ° C. for 1 hour. The solid content (Note 2) of the obtained product was 29.2%, and the viscosity (Note 3) was 75 mPa · s.

3-2) Rutile-type titanium oxide sol (a) A titania sulfate solution is diluted with pure water to obtain
% Aqueous solution was obtained. While maintaining the aqueous solution at 10 ° C. and stirring, 15% aqueous ammonia was added to adjust the pH.
A white suspension of 9.5 was obtained. The suspension was filtered and washed to obtain a hydrated titanium oxide gel cake having a solid content of 10.2%. To 530 parts of the cake, 462 parts of 35% hydrogen peroxide solution and 358 parts of pure water were added, and the mixture was heated at 85 ° C. for 3 hours.
0 parts were obtained. Next, 375 parts of a 1.6% aqueous stannic acid solution as tin oxide, which was obtained by dealkalizing the aqueous solution of potassium stannate with a cation exchange resin, 1350 parts of the above aqueous solution of titanic acid and 3610 parts of pure water were mixed. Further, the average particle size is 7n.
After mixing 57 parts of silica sol having a silica concentration of 15%, the mixture was heated at 150 ° C. for 18 hours to obtain a colloid solution. This colloid solution was concentrated under reduced pressure to obtain a solid content of 2%.
After obtaining 0% titanium oxide sol, an ultrafiltration membrane (trade name, “SIP-1”, manufactured by Asahi Kasei Kogyo Co., Ltd.) is added while adding ethanol.
013 "), and the solid content was 20%.
A titanium oxide sol using ethanol as a dispersion medium was obtained.

The crystal structure of the dispersed particles of this sol by an X-ray diffraction apparatus was a rutile type, and the specific surface area was 180 m ² / g. X-ray diffraction was performed by drying the dispersed particles of the sol at 110 ° C., and then manufactured by Rigaku Corporation, LAD-11C type, Cu tube,
The measurement was performed under the conditions of 5 kv and 12.5 mA. After heating the sol dispersed particles at 100 ° C. for 10 hours,
The specific surface area was measured by a nitrogen adsorption method (BET method) using a specific surface area measuring device (trade name, “Multi-Sop 12” manufactured by Yuasa Ionic Co., Ltd.).

4. Examples 3 to 6 Example 3 The inorganic coating composition (1-1) obtained in Example 1 was mixed with the rutile-type titanium oxide sol (a) obtained in the above sample preparation. The mixing ratio was 50 parts by weight of titanium oxide with respect to 100 parts by weight of the former in terms of solid content. This mixture was further diluted with isobutanol to obtain a solid content of 0.1%.
5% titanium oxide-containing inorganic coating composition (2-1) was obtained.

Example 4 Titanium oxide sol (Note 6) was mixed with the inorganic coating composition (1-1) obtained in Example 1. The mixing ratio is a solid content ratio,
The titanium oxide was 50 parts by weight based on 100 parts by weight of the former. This mixture was further diluted with isobutanol to obtain a titanium oxide-containing inorganic coating composition (2-2) having a solid content of 0.5%. (Note 6) Titanium oxide sol: “ST-K0” manufactured by Ishihara Sangyo Co., Ltd.
3 ", trade name, anatase type titanium oxide sol, titanium oxide content 5%.

Example 5 Hydrolyzate of organosilane compound obtained in sample preparation (a)
Was mixed with rutile-type titanium oxide sol (a). The mixing ratio was 50 parts by weight of titanium oxide with respect to 100 parts by weight of the former in terms of solid content. This mixture was further diluted with isobutanol to obtain a titanium oxide-containing inorganic coating composition (3-1) having a solid content of 0.5%.

Example 6 Hydrolyzate (a) of organosilane compound obtained in sample preparation
Was mixed with titanium oxide sol (Note 6). The mixing ratio is a solid content ratio, and titanium oxide is 5 parts per 100 parts by weight of the former.
0 parts by weight. This mixture was further diluted with isobutanol to obtain a titanium oxide-containing inorganic coating composition (3-2) having a solid content of 0.5%.

5. Examples and Comparative Examples Regarding the Pollution Prevention Method As objects to be coated, plastic, steel plate (a cold-rolled steel plate having a thickness of 0.7 mm, zinc phosphate treatment was performed), aluminum (a plate having a thickness of 0.3 mm, and And glass (produced by Nippon Test Panel Co., Ltd., trade name "J
ISR3202 "Float glass" was used. Of these, cold-rolled steel sheets are subjected to chemical conversion treatment, cationic electrodeposition coating, and intermediate coating as plastic objects to be coated, and acrylic-melamine resin-based black paint (“Magiclon”,
Painted using Kansai Paint Co., Ltd. (trade name) with a thickness of 15 μm, cured by heating at 140 ° C. for 30 minutes, and painted with white paint (“Amirac”) in the same manner did. The black painted object was mainly used for evaluation of finished appearance and adhesion, and the white painted object was used for evaluation of contamination and color difference after outdoor exposure.

As the primer, those obtained by diluting the hydrolyzate (a) of Examples 1 and 2, Comparative Example 1, and the organosilane compound to a solid content of 20% were used. That is, the inorganic coating composition (1-1) of Example 1 was used as a primer (a).
The inorganic coating composition (1-2) of Example 2 was used as a primer (b), and the inorganic coating composition (1-3) obtained in Comparative Example 1 was used as a primer (c). The hydrolyzate (a) was indicated as primer (d).

The inorganic coating composition (2-1) obtained in Example 3 was used as the antifouling paint (a), and the inorganic coating composition (2-2) obtained in Example 4 was used as the antifouling paint. As (b), the inorganic paint composition (3-1) obtained in Example 5 was used as the antifouling paint (c), and the inorganic paint composition (3-2) obtained in Example 6 was used as the antifouling paint. This is indicated as (d).

A primer is applied to the object to be coated to a thickness of 3 to 5 μm by a spray method.
And dried. Thereafter, an antifouling paint was applied to the coated surface by a spray method so that the film thickness became 0.08 to 0.11 μm, and dried at 100 ° C. for 25 minutes.

Table 2 shows the combinations of the substrates, primers and inorganic coatings, and the results of performance tests of the obtained multilayer coating films.

The coating film performance test method is as follows.

Initial stage: After the above-mentioned coating process was completed, the test plate was left at 20 ° C. for 1 hour before the test.

Coated surface condition: The coated surface was visually observed. ○ indicates that the gloss is good and no abnormality is observed in appearance, △ indicates that the gloss is slightly inferior, and cracks are slightly observed, and X indicates that many shiny cracks and cracks are observed.

Adhesion: 100 pieces of 1 mm × 1 mm Gobang were cut with a cutter so as to reach the base material, an adhesive cellophane tape was adhered to the coated surface, and the Gobang after rapidly peeling it off at 20 ° C. The number of remaining eye coats was examined.は indicates 100 remaining, △ indicates 99 to 80, and X indicates 79 or less.

Gloss: 60-degree specular reflectance (%).

Outdoor exposure: A test was conducted on a test plate exposed outdoors in central Tokyo for one year.

Coated surface condition, adhesion, gloss: The coated surface was washed and evaluated according to the above criteria.

Stain resistance: The coated surface after exposure was visually observed.
○ indicates almost the same as before exposure and is not contaminated. △ indicates that black spots are slightly conspicuous on the coated surface, and × indicates black spots are conspicuous on the coated surface, indicating severe contamination.

Color difference: The color difference between the non-washed part of the test plate (white coating film) after the outdoor exposure and the initial coating surface before the exposure was determined by using the “SM Color Computer SM-4” (Suga Test Machine) The L value (whiteness) was measured using a commercial product (trade name). The larger the negative value, the more the pollution is advanced.

[0096]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masami Suwama 4-171-1, Higashi-Yawata, Hiratsuka-shi, Kanagawa Prefecture Inside Kansai Paint Co., Ltd. (72) Inventor Seiji Kashida 4-171-1, Higashi-Yawata, Hiratsuka-shi, Kanagawa F term (reference) in Kansai Paint Co., Ltd. 4J038 AA011 DL031 HA161 HA441 JB11 JC30 MA07 NA05 PA19 PC02 PC03 PC06 PC08 PC10

Claims (14)

[Claims] 1. A repeating unit represented by the following general formula (1): wherein R is a monovalent substituted or unsubstituted hydrocarbon group, and a is 0.8 to 1.8. A polyorganosiloxane having at least 1% by weight of a hydroxyl group bonded to a silicon atom, (B) a compound represented by the following general formula (2): wherein R ′ is the same or different, monovalent substituted or unsubstituted carbon atom 1 to 8 hydrocarbon groups, b is an integer of 0 to 3, X is a hydrolyzable group], (C)
The organic acid quaternary ammonium salt is contained, and the ratio of the component (C) is 10% in total solid content of the component (A) and the component (B).
The inorganic coating composition (1), wherein the amount is 0.05 to 10 parts by weight per 0 parts by weight. General formula (1): RaSiO (4-a) / 2 General formula (2): R'bSix (4-b) 2. The inorganic coating composition (1) according to claim 1, wherein the organic acid quaternary ammonium salt (C) is a carboxylic acid quaternary ammonium salt. 3. Hydrogen peroxide is added to a gel or sol of hydrated titanium oxide to dissolve the hydrated titanium oxide in the inorganic coating composition (1), and TiO2 / SnO2 = 1.
An inorganic coating composition (2) containing a tin compound in a ratio of 5 to 14 (weight ratio of solid content) and containing a composite colloid of rutile-type titanium oxide and tin oxide obtained by heating. 4. A method for preventing contamination of a plastic substrate, comprising forming a film of an inorganic coating composition (2) on the surface of a plastic substrate. 5. A pollution-preventing plastic substrate comprising a plastic substrate and a coating of an inorganic coating composition (2) formed on the surface thereof. 6. A coating material of an inorganic coating composition (1) is formed on the surface of a plastic substrate, and then a coating film of an inorganic coating composition (2) is formed on the coated surface. To prevent contamination of plastic substrates. 7. A coating material of an inorganic coating composition (1) is formed on the surface of a plastic substrate, and a coating film of an inorganic coating composition (2) is formed on the coated surface. Plastic base material. 8. A coating film of an inorganic coating composition (1) is formed on a surface of a plastic substrate, and
(C) coating a coating composition (3) containing a hydrolyzable organic silane compound represented by the general formula (2) or a hydrolysis product thereof, and a titanium oxide sol or the above composite colloid. To prevent contamination of plastic substrate surface. 9. A plastic substrate obtained according to claim 8. 10. A coloring agent for the inorganic coating composition (1),
The method for preventing contamination according to claim 1, 6, 7, 8, or 9, further comprising a glittering material. 11. A plastic substrate obtained by the method according to claim 10. 12. The method according to claim 12, wherein the plastic substrate is polycarbonate.
A plastic molded product selected from the group consisting of polymethyl methacrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, ABS resin, polyurethane, polyolefin resin, cellulose acetate, polyethylene terephthalate, and unsaturated polyester resin. Terms 4, 5, 6, 7, 8, 9, 1
The method for preventing contamination of a plastic substrate according to 0. 13. A plastic substrate, a plastic molded body, an organic coating film coated on a surface of a ferrous or non-ferrous metal,
The method for preventing contamination of a plastic substrate according to claim 4, which is an organic coating film applied on the surface of the plastic molded body, and has a glass transition temperature of 50 to 130 ° C. . 14. The method according to claim 4, wherein the base material is iron, non-ferrous metal, glass, ceramic, fiber, wood.
9. The method for preventing contamination of a substrate according to 9 or 10.