JP2001259523A - Coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method which can form an inorganic top coat film which can be dried at room temperature or at relatively lower temperature and is excellent in adhesion, hardness, coloring by colored pigment, and thickness holding. SOLUTION: In the coating method, after a primer selected from an epoxy resin coating and an acryl silicone coating is applied on a substrate and dried to form a primer film, and on the primer film, the inorgainc top coat containing the dealcohol-condensation product of a mixture, in which (A) on the basis of 100 pts.wt. of alkyl aryl alkoxy polysiloxane 500-4,000 in weight average molecular weight and 10-30 wt.% in alkoxyl group content, (B) 5-1,000 pts.wt. of alkyltrialkoxy silane condensate 300-2,000 in weight average molecular weight and 25-50 wt.% of in alkoxy group content is contained, and on the basis of 100 pts.wt. of the sum of (A) component and (B) component, (C) 3-100 pts.wt. of epoxy-group-containing alkoxy silane is contained, as a resin component is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a coating method using an inorganic top coat.

[0002]

2. Description of the Related Art Inorganic paints have high hardness and are excellent in adhesion, water resistance, stain resistance, and weather resistance. Wood, cement, slate,
It is used as a coating agent for mortar and other inorganic ceramic substrates. Conventionally, these inorganic paints have had to cure a coating film by heat energy by heating.

[0003] Under such circumstances, there has been an increasing demand for inorganic coatings which can be cured at room temperature or at a relatively low temperature. Organosiloxane-type inorganic paints that cure at room temperature are disclosed in, for example, JP-A-6-240207 and JP-A-10-060377.

[0004] The organosiloxane type inorganic paint described in JP-A-6-240207 is composed of a silica-dispersed oligomer solution of an organosilane, a silanol group-containing polyorganosiloxane, and a curing catalyst. Therefore, there is a problem that it is difficult to secure a necessary film thickness.

The organosiloxane type inorganic paint described in JP-A-10-060377 comprises a silanol-containing polyorganosiloxane, a glycidoxypropyl group-containing silane, a silane having at least two hydrolyzable groups, and a curing catalyst. However, there is a problem that the pigment dispersion stability is poor and coloring is difficult.

Further, a coating film obtained from an inorganic coating material has a problem that adhesion to an alkali base material such as cement, mortar, slate or the like or an organic coating film is not sufficient.

An object of the present invention is to provide a coating method which can be dried at room temperature or at a relatively low temperature, and which can form an inorganic top coat having excellent adhesiveness, coating film hardness, colorability with a coloring pigment, film thickness retention and the like. It is to provide.

[0008]

Means for Solving the Problems The present inventors have conducted various studies in order to achieve the above object, and as a result, have found that a dried undercoat film of epoxy resin paint or acrylic silicone paint is coated on the substrate. The above-mentioned object can be achieved by applying an inorganic topcoat containing a specific alcohol arylalkoxypolysiloxane, an alkyltrialkoxysilane condensate, and a dealcoholation condensation reaction product of an epoxy group-containing alkoxysilane as a resin component. The present invention has been completed.

That is, according to the present invention, an undercoat selected from an epoxy resin-based paint and an acrylic silicone-based paint is applied on an object to be coated, dried to form an undercoat, and then, A) the following rational formula ^{_{R 1 a R 2 b (R}} 3 O) c SiO ( in _{4-abc) / 2} formula, R ¹ and R ³ are the same or different, carbon atoms 1-8
Represents an alkyl group, R ² represents an aryl group, and a represents 0.
1 ≦ a ≦ 2.0, b is 0.1 ≦ b ≦ 2.0, and b / a is 0.2 ≦ b / a ≦ 2.0, c is 0.1 ≦ c ≦ 1.0, (A
+ B + c) is less than 4, and has a weight average molecular weight of 500 to 6,000.
100 parts by weight of an alkylarylalkoxypolysiloxane having an alkoxyl group content in the range of 10 to 30% by weight based on the polysiloxane;
(B) The following general formula R ⁴ Si (OR ⁵ ) _{3 wherein} R ⁴ and R ⁵ are the same or different and have 1 to 8 carbon atoms.
A condensate of an alkyl trialkoxysilane represented by an alkyl group having a weight average molecular weight in the range of 300 to 3,000, and having an alkoxyl group content of 20 to 55 based on the condensate. 0 to 500 parts by weight of the alkyltrialkoxysilane condensate in the range of weight%, the alkylarylalkoxypolysiloxane (A) and the alkyltrialkoxysilane condensate (B)
Based on the total 100 parts by weight of, (C) the following general formula _{^{R 6 R 7 n Si (OR}} 8) (3-n) wherein the organic group R ⁶ is containing an epoxy radical, n pieces of R ⁷
Are the same or different and each have an alkyl group having 1 to 8 carbon atoms;
R ⁸ is the same or different and is a hydrogen atom or a carbon atom
Represents an alkyl group, and n represents an integer of 0 to 2; and coating an inorganic top coat containing as a resin component a dealcoholization condensation reaction product with 3 to 100 parts by weight of an epoxy group-containing alkoxysilane represented by And a coating method characterized by the following.

[0010] In the present invention, the inorganic top coating composition may further comprise an amino group-containing alkoxysilane based on one equivalent of the epoxy group of the dealcoholization condensation reaction product, wherein the active hydrogen of the amino group is 0.3 to 3.0. An object of the present invention is to provide the coating method as described above, wherein the coating material contains an equivalent amount.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The coating method of the present invention will be described below in detail. In the coating method of the present invention, an undercoat selected from an epoxy resin-based paint and an acrylic silicone-based paint is applied on an object to be coated, dried to form an undercoat, and then a specific undercoat is formed on the undercoat. Apply inorganic top coat.

The object to be coated is iron, aluminum,
Metal substrates such as stainless steel, galvanized steel plates, zinc alloy-plated steel plates (plated with alloys such as iron-zinc, nickel-zinc, and aluminum-zinc), and tin plates; plastic substrates; glass, cement, slate, Inorganic ceramic substrates such as mortars and tiles; and coated substrates obtained by coating these substrates with coating films.

In the method of the present invention, the undercoat paint to be applied on the object is selected from an epoxy resin paint and an acrylic silicone paint.

As the epoxy resin-based paint, there can be mentioned a known epoxy resin-based paint as a sealer or an undercoat, and typical examples thereof include an epoxy-amine resin-based paint and an epoxy urethane resin-based paint. And the like.

As the acrylic silicone paint, (1)
Polymer of a monomer mixture comprising an alkoxysilyl group-containing polymerizable unsaturated monomer or polysiloxane macromonomer such as γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, and other polymerizable unsaturated monomers ;
(2) A paint containing, as a resin component, a condensation polymer obtained by subjecting an alkoxysilyl group-containing organopolysiloxane and a hydroxyl group-containing acrylic resin to a dealcoholization reaction. The acrylic silicone-based paint may contain, for example, a curing agent such as a polyisocyanate compound.

The undercoat paint contains, in addition to the binder component, an organic solvent, pigments such as color pigments, extender pigments, rust-preventive pigments, and other paint additives such as a curing catalyst, a coating surface adjuster, and an anti-drip agent. Can be.

The organic solvent that can be contained in the undercoat paint can be used without any particular limitation as long as it can dissolve or disperse the resin in the undercoat paint. However, in the method of the present invention, the surface of the substrate on which the undercoat paint is applied has deteriorated. In the case of the old paint film surface, when the undercoat paint is applied over the old paint film, it is necessary that lifting of the old paint film does not occur, and for that, the aliphatic hydrocarbon solvent and the boiling point It is preferable that the composition contains at least 95% by weight of a hydrocarbon solvent selected from high-boiling aromatic hydrocarbon solvents having a temperature of 150 ° C. or higher, based on the total amount of the organic solvent in the undercoat paint.

Specific examples of the above-mentioned aliphatic hydrocarbon solvents and high-boiling aromatic hydrocarbon solvents include, for example, VM & P
Naphtha, Mineral Spirit, Solvent Kerosene, Aromatic Naphtha, Solvent Naphtha, Solvesso 100, Solvesso 150, Solvesso 200 [“Solvesso” is a registered trademark of Esso Oil Co., Ltd.], Swazol 310, Swazol 1000, Swazol 1500 [“Swazol” is Cosmo Aliphatic or aromatic hydrocarbons having a relatively low dissolving power, such as n-butane, n-hexane, n-heptane, n-octane, isononane, n-decane, n-dodecane And aliphatic hydrocarbons such as cyclopentane, cyclohexane and cyclobutane. In this case, the organic solvent in the undercoat paint is most preferably an aliphatic hydrocarbon-based solvent or a high-boiling aromatic hydrocarbon-based solvent, but the organic solvent includes an aliphatic hydrocarbon-based solvent and a high-boiling-point solvent. It may contain 5% or less, preferably 3% or less of other organic solvents other than the aromatic hydrocarbon solvent. When the amount of the other organic solvent increases, lifting of the old coating film easily occurs at the time of recoating.

The above-mentioned undercoat paint is dried after application to form an undercoat film. The drying conditions can be appropriately set according to the kind of the undercoat paint and the like. It can be cured by curing or the like.

In the method of the present invention, the inorganic top coat applied on the undercoat film includes the following alkylarylalkoxypolysiloxane (A), alkyltrialkoxysilane condensate (B) and epoxy group-containing alkoxysilane (C). As a resin component.

Alkylarylalkoxypolysiloxa
(A) Alkylarylalkoxypolysiloxane ( hereinafter sometimes abbreviated as “polysiloxane (A)”) as a component (A) is a polysiloxane containing an alkyl group, an aryl group and an alkoxy group. following rational formula ^{_{R 1 a R 2 b (R}} 3 O) c SiO (4-abc) / ₂ wherein, R ¹ and R ³ are the same or different, 1 to carbon atoms
8, preferably 1 to 4 alkyl groups, R ² represents an aryl group, a is 0.1 ≦ a ≦ 2.0, b is 0.1 ≦ b ≦
2.0 and b / a is 0.2 ≦ b / a ≦ 2.0, c
Is 0.1 ≦ c ≦ 1.0, and (a + b + c) is less than 4.

Since the polysiloxane (A) has an aryl group in the above-mentioned quantitative range, it has excellent film-forming properties. The polysiloxane (A) has a weight average molecular weight (in terms of polystyrene) of 500 to 6,000, particularly 700 to 6,000.
It is preferred that the content be in the range of 4,000, and the content of the alkoxyl group be in the range of 10 to 30% by weight, particularly in the range of 15 to 25.

Alkyl trialkoxysilane condensate
(B) Alkyl trialkoxysilane condensate as the component (B) [hereinafter sometimes abbreviated as “condensate (B)”]
Is a compound represented by the following general formula: R ⁴ Si (OR ⁵ ) _{3 wherein} R ⁴ and R ⁵ are the same or different and have 1 to 1 carbon atoms.
8, preferably a condensate of an alkyl trialkoxysilane represented by 1 to 4 alkyl groups, having a weight average molecular weight of 300 to 3,000, preferably 500 to 2,000. , A condensate having an alkoxyl group content in the range of 20 to 55% by weight, preferably 25 to 50% by weight, based on the condensate.

Specific examples of the alkyltrialkoxysilane used in the production of the condensate (B) include, for example, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane And methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, butyltriethoxysilane, methyltripropoxysilane, propyltripropoxysilane, and methyltributoxysilane. When producing the condensate (B), these alkyl trialkoxysilanes can be used alone or in combination of two or more.

Epoxy group-containing alkoxysilane (C) The epoxy group-containing alkoxysilane (hereinafter sometimes abbreviated as “epoxysilane (C)”) as the component (C) is represented by the following general formula R ⁶ R ⁷ _n Si (oR ⁸⁾ in _(3-n) formula, R ⁶ is an organic group containing an epoxy radical, n pieces of R ⁷ are the same or different, 1 to 8 carbon atoms, preferably 1 to 4
Wherein R ⁸ is the same or different and represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4; and n represents an integer of 0 to 2; Compound.

Specific examples of the epoxysilane (C) include, for example, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, and γ-glycidoxyethyltriethoxysilane.
Glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl (methyl) dimethoxysilane, γ-glycidoxypropyl (dimethyl) methoxysilane, γ-glycidoxypropyl (ethyl ) Dimethoxysilane, 3,4-epoxycyclohexylmethyltrimethoxysilane, β-
(3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like can be mentioned. These epoxy group-containing alkoxysilanes can be used alone or in combination of two or more.

In the present invention, the polysiloxane (A), the condensate (B) and the epoxysilane (C) are subjected to a dealcoholization condensation reaction by heating in the presence of a reaction catalyst and water to obtain a resin composition of the present invention. Manufacturing things. In producing the resin composition of the present invention, the polysiloxane (A) is bonded to Si in the polysiloxane (A) by heating the polysiloxane (A) in advance in the presence of a reaction catalyst and water without removing alcohol from the reaction system. Part of the alkoxy group is represented by S
After changing to a hydroxyl group (silanol group) bonded to i,
A condensate (B) and an epoxysilane (C) may be added to the mixture, and the alcohol may be removed from the system by heating to cause a dealcoholization condensation reaction. Further, a mixture of the polysiloxane (A) and the condensate (B) is heated in advance in the presence of a reaction catalyst and water without removing the alcohol from the reaction system, so that the polysiloxane (A) and the condensate (B) are heated. ), A part of the alkoxy group bonded to Si in Si)
After changing to a hydroxyl group (silanol group) bonded to the compound, epoxysilane (C) may be added thereto, and the alcohol may be removed from the system by heating to carry out a dealcoholization condensation reaction. Further, the polysiloxane (A), the condensate (B), and the epoxysilane (C) are simultaneously heated in the presence of a reaction catalyst and water to remove the generated alcohol to the outside while removing alcohol. The condensation reaction may proceed.

In the above reaction, (A), (B) and / or
Alternatively, the condensation reaction is suppressed by heating the component (C) in the presence of the reaction catalyst and water without removing the alcohol from the reaction system. The part can be changed to a hydroxyl group (silanol group) bonded to Si. Since the generated silanol group is more likely to cause a condensation reaction than the alkoxysilyl group, a part of the alkoxy group bonded to Si, which is a component that is less likely to cause a condensation reaction than other components, is bonded to Si. The condensation reaction can be controlled by changing it to a hydroxyl group (silanol group) in advance.

The proportions of the respective components of the polysiloxane (A), the condensate (B) and the epoxysilane (C) are as follows. The amount of the condensate (B) is from 0 to 500 based on 100 parts by weight of the polysiloxane (A).
It is preferably in the range of 10 parts by weight, particularly 10 to 200 parts by weight, from the viewpoint of room temperature curability, coating film hardness and adhesiveness. The compounding amount of the epoxy silane (C) is in the range of 3 to 100 parts by weight, particularly 5 to 50 parts by weight based on 100 parts by weight of the total of the polysiloxane (A) and the condensate (B). This is preferable from the viewpoints of room temperature curability, pot life and adhesion.

As the reaction catalyst in the above dealcoholization condensation reaction, metal alkoxide compounds, metal chelate compounds, metal ester compounds, inorganic acids, organic acids and the like are used. Examples of the metal alkoxide compound include aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum trisec-butoxide, and aluminum. Aluminum alkoxide such as tri-tert-butoxide; Titanium alkoxide such as tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra n-butyl titanate, tetraisooctyl titanate; tetraethyl zirconate, tetra n-propyl Zirconate, tetraisopropyl zirconate, tetra n-butyl zirconate, tetra n-octyl zirconate And the like. Examples of the metal chelate compound include tris (ethylacetoacetate) aluminum, tris (n-propylacetoacetate) aluminum, tris (isopropylacetoacetate) aluminum, and tris (n). -Butylacetoacetate) aluminum, isopropoxybis (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, tris (proponylacetonato) aluminum, diisopropoxypropionylacetonatoaluminum, acetylacetonatobis (propionylacetone) Nato) aluminum, monoethyl acetoacetate bis (acetylacetonato) aluminum, acetylacetonato aluminum di-sec
Aluminum chelate compounds such as butyrate; diisopropoxy bis (ethylacetoacetate) titanate;
Titanium chelate compounds such as diisopropoxy bis (acetylacetonato) titanate; zirconium chelate compounds such as tetrakis (acetylacetonato) zirconium and tetrakis (n-propylacetoacetate) zirconium; dibutyltin bis (acetylacetonate); Examples of the metal ester compound include tin ester compounds such as dibutyltin diacetate, dibutyltin di (2-ethylhexylate), and dibutyltin dilaurate. Examples of the inorganic acid include nitric acid, hydrochloric acid, and phosphoric acid, and examples of the organic acid include acetic acid, formic acid, and propionic acid. These reaction catalysts can be used alone or in combination of two or more.

The amount of the reaction catalyst used is usually 0.001 parts by weight based on a total of 100 parts by weight of the components (A), (B) and (C).
It is preferred that the amount be in the range of 01 to 1 part by weight. The amount of water is usually 0.02 to 1 equivalent of the alkoxysilyl group in the total of the components (A), (B) and (C).
Preferably it is in the range of 0.4 mol.

In the dealcoholization condensation reaction, the reaction conditions are not particularly limited. However, the reaction is carried out without removing the alcohol from the reaction system in the presence of a reaction catalyst and water without removing the alcohols from (A) and (B). ) And / or (C)
When a part of the alkoxy group bonded to Si in the component is changed to a hydroxyl group (silanol group) bonded to Si, it is usually at room temperature to 100 ° C. for 5 minutes to 5 hours, particularly 40 to 100 hours.
Stir without removing alcohol at 80 ° C. for 10 minutes to 3 hours, then stir at 60 to 250 ° C. (preferably 100 ° C.)
(200 ° C. to 200 ° C.), and the reaction is preferably performed for 1 hour to 24 hours while removing the alcohol generated by the reaction. When the step of heating without removing the alcohol from the reaction system in the presence of the reaction catalyst and water is not performed, usually 60 to 250 ° C (preferably 100 ° C to 200 ° C)
The reaction is preferably carried out for 1 hour to 24 hours while removing the alcohol generated by the reaction.

The dealcoholization condensation product has an epoxy equivalent of 300 to 5,000, particularly 500 to 4,000, and a weight average molecular weight (in terms of polystyrene) of 1,000.
It is in the range of 0 to 40,000, especially 2,000 to 30,000, and in the infrared absorption spectrum, [absorption based on silanol group (around 3400 cm ^-1 ) / absorption based on siloxane (around 1080 cm ^-1 )] The absorbance ratio is 0.04 or less, desirably 0.03 or less,
It is suitable from the viewpoint of pigment dispersion stability.

The inorganic top coat used in the method of the present invention contains the above dealcoholization condensation reaction product as a resin component, and usually further contains a curing agent.
Examples of the curing agent include an amino group-containing alkoxysilane. Specific examples of the amino group-containing alkoxysilane include, for example, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N-
(2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and the like can be mentioned. These compounds can be used alone or in combination of two or more.

When an amino group-containing alkoxysilane is used as a curing agent in the inorganic top coat, the mixing ratio between the dealcoholization condensation reaction product and the amino group-containing alkoxysilane is determined by the number of equivalents of the active hydrogen of the amino group. /
When the ratio of the number of equivalents of the epoxy group in the dealcoholization condensation reaction is in the range of 0.3 to 3.0, particularly 0.5 to 1.5, the curing of the obtained top coat paint It is suitable from the viewpoints of properties and pot life.

The above-mentioned inorganic overcoating material includes, in addition to the above-mentioned dealcoholization condensation product and amino-containing alkoxysilane,
Further, if necessary, a curing catalyst; iron oxide, titanium oxide,
Color pigments such as carbon black, cyanine blue, cyanine green and quinacridone red, extenders such as calcium carbonate, talc, clay, silica, barium sulfate and mica; organic solvents; and other additives can be contained.

The curing catalyst promotes a curing reaction between the resin composition and the amino group-containing alkoxysilane. Specific examples of the curing catalyst include aqueous alkali metals such as sodium hydroxide and potassium hydroxide. Oxides; hydrochloric acid,
Inorganic acids such as sulfuric acid and phosphoric acid; organic acids such as acetic acid and p-toluenesulfonic acid; quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrabutylammonium hydroxide; dibutylamine-2 Amine salts such as hexoate, dimethylamine acetate, ethanolamine acetate; quaternary ammonium salts of carboxylic acids such as tetramethylammonium acetate; amines such as tetraethylpentamine; aluminum alkoxides; aluminum chelates; tetraisopropyl titanate; Organic titanium compounds such as titanate and titanium tetraacetylacetonate; dibutyltin diacetate;
Organic acid tin ester compounds such as dibutyltin dilaurate;
Imidazole derivatives such as imidazole, 1-methylimidazole, 2-methylimidazole and 4-methylimidazole; and piperidine, piperazine, pyrrolidine and the like. These curing catalysts can be used alone or
More than one species can be used in combination.

When the above curing catalyst is blended, the blending amount is 0.0001 to 1 based on 100 parts by weight of the total of the resin composition and the amino group-containing alkoxysilane.
It is preferably in the range of parts by weight.

In the method of the present invention, the method of applying the above-mentioned top coat on the undercoat film is not particularly limited, and examples thereof include brush coating, air spray coating, airless spray coating, roll coater, and the like. The coating can be performed using a flow coater or the like, and the coating film thickness is not particularly limited, but is usually preferably in the range of 5 to 60 μm. This inorganic top coat can be cured at room temperature, and the cured coating film exhibits excellent performance, but may be subjected to forced drying or heat curing.

According to the method of the present invention, it is possible to form an inorganic overcoat film which can be dried at room temperature or a relatively low temperature, has excellent adhesion, coloring properties with a coloring pigment, excellent film thickness retention, and excellent gloss and weather resistance. .

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments. In the following, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively, unless otherwise specified.

Production Example 1 Production of De-alcohol Condensation Reaction Liquid (a) "DC3074" (manufactured by Toray Dow Corning Silicone Co., Ltd., alkylaryl 100 parts of alkoxysilane oligomer, phenyl group content (about 1 equivalent of organic group, the same applies hereinafter), about 50 equivalent%, methoxy group content about 17%, weight average molecular weight about 1600), "XR31B-1
410 "(manufactured by Toshiba Silicone Co., Ltd., partial condensate of alkyl trialkoxysilane, methoxy group content of about 45 to 5).
0% by weight, weight average molecular weight of about 500), 10 parts of γ-glycidoxypropyltrimethoxysilane, 10 parts of methyl alcohol, and 0.2 parts of diisopropoxybisacetylacetonato titanium, and heated to 50 ° C. Thereafter, 5.5 parts of water was added dropwise over 15 minutes. Thereafter, after stirring at 70 ° C. for 1 hour, the mixture was heated to 100 ° C. while blowing in nitrogen gas to remove the distilling solvent, and stirring was continued at the same temperature for 16 hours to produce a dealcoholization condensation reaction liquid (a). . The dealcoholization condensation reaction liquid (a) had a nonvolatile content of 92%, a weight average molecular weight of about 10,300, and an epoxy equivalent of 560. In the infrared absorption spectrum (IR), the ratio of the absorbance of the absorption of silanol (absorption at 3400 cm ^-1 ) / the absorption of siloxane (absorption at 1080 cm ^-1 ) was 0.02.

Production Example 2 Production of dealcoholization condensation reaction liquid (b) 100 parts of "DC3074" (described above), "SR2" were placed in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, and a distilling tube.
402 "(manufactured by Dow Corning Toray Silicone Co., Ltd., partial condensate of alkyl trialkoxysilane, methoxy group content: about 34%, weight average molecular weight: about 800), 50 parts, γ
-20 parts of glycidoxypropyltrimethoxysilane, 10 parts of isopropyl alcohol and 0.2 part of diisopropoxybisacetylacetonato titanium were charged, and after raising the temperature to 50 ° C, 4.5 parts of water was added dropwise over 15 minutes. . afterwards,
After stirring at 70 ° C. for 1 hour, the mixture was heated to 120 ° C. while blowing in nitrogen gas to remove the distilling solvent, stirring was continued at the same temperature for 8 hours, 15 parts of xylene was charged, and the dealcoholization condensation reaction liquid (b ) Manufactured. The dealcoholation condensation reaction liquid (b) has a nonvolatile content of 79% and a weight average molecular weight of about 1
8,000 and epoxy equivalent was 2,260. In the infrared absorption spectrum (IR), the ratio of the absorbance of silanol (absorption at 3400 cm ^-1 ) to the absorption of siloxane (absorption at 1080 cm ^-1 ) was 0.01.

Production Example 3 Production of Inorganic Top Coating Paint (A) 108.7 parts of a dealcoholization condensation reaction liquid (a) having a non-volatile content of 92% obtained in Production Example 1 was added to "Taipek CR-9".
3 "(manufactured by Ishihara Sangyo Co., Ltd., trade name: titanium white), 100 parts and 10 parts of toluene were added and mixed, and pigment was dispersed using a paint shaker to obtain a paint base (A-1).
Separately, 3.0 parts of γ-aminopropyltriethoxysilane and 0.1 part of dibutyltin diacetate were mixed to obtain a coating curing agent (C). Immediately before coating, 218.7 parts of the base for coating (A-1) and 3.1 parts of the curing agent for coating (C) were mixed to prepare an inorganic top coating (A), which was used for coating. The inorganic top coat (A) had good coloring properties.

Production Example 4 Production of Inorganic Topcoat (B) 105.3 parts of a dealcoholization-condensation reaction liquid (b) having a nonvolatile content of 79% obtained in Production Example 2 was added to "Taipek CR-9".
3 "(manufactured by Ishihara Sangyo Co., Ltd., trade name: titanium white), 100 parts and toluene 10 parts were added and mixed, and pigment was dispersed using a paint shaker to obtain a paint base (B-1).
Immediately before the coating, 215.3 parts of the base for coating (B-1) and 3.1 parts of the curing agent for coating (C) were mixed to prepare an inorganic top coating (B), which was used for coating. The inorganic top coating (B) had good coloring properties.

Example 1 A mortar board having a size of 150 × 70 × 20 mm was coated with “Multi-tile concrete primer EPO” (trade name, manufactured by Kansai Paint Co., Ltd., epoxy-amine resin-based primer) at 120 g / m ^2. And dried in a room at a temperature of 20 ° C. and a humidity of 65% RH for 1 day, and then 100 g of the inorganic top coating material (A) obtained in Production Example 3 above. / M ² , and dried in a room at a temperature of 20 ° C. and a humidity of 65% RH for 10 days to obtain a coated plate.

Example 2 A coated plate was prepared in the same manner as in Example 1 except that the inorganic topcoat (B) obtained in Production Example 4 was used instead of the inorganic topcoat (A). Obtained.

Example 3 In Example 1, "Ales Silicone" (manufactured by Kansai Paint Co., Ltd., trade name, acrylic silicone resin-based paint) in place of "Multi-tile concrete primer EPO"
Was carried out in the same manner as in Example 1 except for using, to obtain a coated plate.

Example 4 As a top coat, "Alesletan" (manufactured by Kansai Paint Co., Ltd.)
Product name, acrylic urethane resin-based top coating) is coated on the surface of a coated plate that has been baked for three years at a bakery in Okinoerabu, Okinawa Prefecture. Primer EPO 12
It was brush-coated so as to have a coating amount of 0 g / m ² (dry coating weight), dried in a room at a temperature of 20 ° C. and a humidity of 65% RH for 1 day, and then the inorganic top coat obtained in Production Example 3 ( A) is 100
It was brush-coated so as to have a coating amount (dry coating weight) of g / m ² and dried in a room at a temperature of 20 ° C. and a humidity of 65% RH for 10 days to obtain a coated plate.

Example 5 A coated plate having on its surface a coating film of "SD Super Marine Topcoat" (trade name, manufactured by Kansai Paint Co., Ltd., long oil phthalate resin-based topcoat, conforming to JIS K5516 2 types) as a topcoat Was used as a base material for three years at a backyard in Okinoerabu, Okinawa Prefecture, and "Esco Mild NB" (Kansai Paint Co., Ltd., trade name, weak solvent type epoxy resin paint ) Was applied with a brush so as to give a coating amount (dry coating weight) of 120 g / m ² ,
Preparation Example 3 after drying in a room at 65 ° C. and a relative humidity of 65% for one day.
The inorganic top coat (A) obtained in the above was brush-coated so as to give a coating amount (dry coating weight) of 100 g / m ² ,
The coated plate was dried in a room at a temperature of 65 ° C. and a relative humidity of 65% for 10 days.

Comparative Example 1 The procedure of Example 1 was repeated, except that “Allethretan” was used in place of the inorganic top coat (A).

Comparative Example 2 A coated plate was prepared in the same manner as in Example 1, except that the inorganic topcoat paint (A) was directly applied to the mortar plate without applying the “multi-tile concrete primer EPO”. Obtained.

Comparative Example 3 A coating was performed in the same manner as in Example 5 except that “Esco mild NB” was not applied and the inorganic top coating (A) was applied directly on the coating film of the substrate. I got a board.

The coated plates obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were tested for initial adhesion and accelerated weather resistance according to the following test methods. The results of these tests are shown in Table 1 below.

Test Method Painted surface condition: The painted surface of the coated plate was visually observed, and the
Evaluations were made for abnormalities such as cracks, peeling, discoloration, and chalking.

Adhesion: JIS K5400 8.5.
2 (1990), according to the grid-tape method,
Six parallel and vertical knife wounds reaching the substrate were made on the coating surface of the coated plate, and 25 squares of 2 mm x 2 mm were created. A cellophane pressure-sensitive adhesive tape was adhered to the grid, and was instantaneously peeled off, and the ratio of the number of cells remaining without peeling out of the 25 cells was described.

Coating film hardness: JIS K5400 8.4.
2 (1990), a pencil scratch test was performed, and evaluation was performed by the blurring method.

Accelerated weathering test: The coated plate was subjected to an accelerated weathering test for 5,000 hours using a sunshine carbon arc weatherometer. The coated surface state and adhesion of the coated plate after the test were evaluated. The test was conducted on the coated surface of the coated plate after the test in the same manner as in the test method of the coated surface, and the adhesion of the coated plate after the test was tested in the same manner as the test method of the adhesiveness.

[0059]

[Table 1]

[0060]

According to the coating method of the present invention, it is possible to form an inorganic topcoat film which can be dried at room temperature or at a relatively low temperature, and is excellent in adhesiveness, hardness of the coating film, coloring by a coloring pigment, and film thickness retention.

In the method of the present invention, by using a weak solvent type epoxy resin-based paint or acrylic silicone-based paint as the undercoat paint, abnormalities such as shrinkage during painting can be prevented even when the paint is applied on the deteriorated old paint film. In addition, it is possible to form an inorganic overcoating film having excellent coating surface appearance and coating film performance.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 AE03 AE16 EB01 EB33 EB43 4J038 DL031 DL032 DL051 DL052 DL081 DL082 GA07 GA09 MA14 NA03 NA04 NA05 NA11 PC02 PC03 PC04 PC08

Claims (3)

[Claims] 1. An undercoat selected from an epoxy resin-based paint and an acrylic silicone-based paint is applied on an object to be coated and dried to form an undercoat, and then: (A) rational formula R in _{^{1 a R 2 b (R 3}} O) c SiO (4-abc) / 2 formula, R ¹ and R ³ are the same or different, 1 to 8 carbon atoms
Represents an alkyl group, R ² represents an aryl group, and a represents 0.
1 ≦ a ≦ 2.0, b is 0.1 ≦ b ≦ 2.0, and b / a is 0.2 ≦ b / a ≦ 2.0, c is 0.1 ≦ c ≦ 1.0, (A
+ B + c) is less than 4, and has a weight average molecular weight of 500 to 6,000.
And 100 parts by weight of an alkylarylalkoxypolysiloxane having an alkoxyl group content in the range of 10 to 30% by weight based on the polysiloxane; and (B) the following general formula: R ⁴ Si (OR ⁵ ) _{In the} formula, R ⁴ and R ⁵ are the same or different and each have 1 to 8 carbon atoms.
A condensate of an alkyl trialkoxysilane represented by an alkyl group having a weight average molecular weight in the range of 300 to 3,000, and having an alkoxyl group content of 20 to 55 based on the condensate. 0 to 500 parts by weight of the alkyltrialkoxysilane condensate in the range of weight%, the alkylarylalkoxypolysiloxane (A) and the alkyltrialkoxysilane condensate (B)
Based on the total 100 parts by weight of, (C) the following general formula _{^{R 6 R 7 n Si (OR}} 8) (3-n) wherein the organic group R ⁶ is containing an epoxy radical, n pieces of R ⁷
Are the same or different and each have an alkyl group having 1 to 8 carbon atoms;
R ⁸ is the same or different and is a hydrogen atom or a carbon atom
Represents an alkyl group, and n represents an integer of 0 to 2; and coating an inorganic top coat containing as a resin component a dealcoholization condensation reaction product with 3 to 100 parts by weight of an epoxy group-containing alkoxysilane represented by A coating method characterized by the following. 2. The inorganic top coating composition according to claim 1, wherein the equivalent of the epoxy group of the dealcoholization condensation reaction product is an amino group-containing alkoxysilane, and the active hydrogen of the amino group is 0.3 to 3.0.
2. The coating method according to claim 1, wherein the coating material contains 3.0 equivalents. 3. The object to be coated has an old coating film, and is selected from an epoxy resin-based coating material and an acrylic silicon-based coating material as an undercoating material on the old coating film of the object to be coated. 2. An undercoat paint is applied.
Or the coating method of 2.