JPH0987588A - Curable coating composition and coated article coated therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable coating compsn. hardly toxic and improved in storage stability, adhesion to a recoating film, etc., by compounding two specific vinyl copolymers, a hydroxyl compd., and a curing catalyst. SOLUTION: This compsn. is prepd. by compounding a noncarboxylated vinyl copolymer having at least one hydrolyzable silyl group represented by formula I (wherein R<1> and R<2> are each H, a 1-10C alkyl, an aryl, or an aralkyl; and (a) is 0-2) at the molecular terminal and/or in the side chain in the molecule, alcoholic hydroxyl groups in the same molecule, a silicon equivalent of 300-30,000, and an alcoholic hydroxyl equivalent of 400-15,000, a carboxylated vinyl copolymer having at least one hydrolyzable silyl group represented by formula II (wherein R<3> and R<4> are each the same as R<1> ; and (b) is a) at the molecular terminal and/or in the side chain in the molecule, alcoholic hydroxyl groups in the same molecule, a silicon equivalent of 1,000-15,000, and an alcoholic hydroxyl equivalent of 200-10,000, a hydrolyzable hydroxyl compd. having no silyl group and a number average mol.wt. of 1,000-25,000, and a curing catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition for paints and a coated product obtained by applying the same, and more specifically, to a curable composition for paints having low toxicity, good storage stability and good recoat adhesion. And a coated product excellent in the balance of curability, appearance, acid resistance, and weather resistance obtained by applying this composition, and particularly, a curable composition for a coating useful as a coating for automobile top coating, and the coated composition Regarding painted objects.

[0002]

2. Description of the Related Art Conventionally, paint resins used for automobiles, building exteriors, industrial machines, steel furniture, plastics, etc. are mainly melamine resins such as alkyd melamine and acrylic melamine. Alternatively, a two-component urethane resin has been used.

Among these, the melamine resin has a problem that harmful formalin is generated at the time of curing and that the cured coating film is inferior in acid resistance and is violated by acid rain. Also,
In the two-component urethane resin, the toxicity of the isocyanate compound used has been a problem.

In order to solve these problems, the present inventors have used a vinyl-based copolymer having a silicon atom bonded to a hydrolyzable group (hereinafter, also referred to as "hydrolyzable silyl group") in a coating material. I'm considering that. As a result, it was found that this polymer solves the above problems and becomes a curable resin for coatings having excellent weather resistance, and has previously applied for a patent (Japanese Patent Application Laid-Open No. 63-132977, etc.).

A characteristic of the vinyl copolymer having a hydrolyzable silyl group is that the silyl group is hydrolyzed by moisture in the air and cured through a condensation reaction. Further, since it forms and cures a stable siloxane bond, it is superior in chemical resistance and weather resistance as compared with the case of using a melamine resin such as acrylic melamine or alkyd melamine and a two-pack type urethane resin. .

By the way, generally, there are two types of top coat finishes for automobiles: metallic color finish and solid color finish.

[0007] Of these, in the case of metallic color finish, after applying a metallic base coat, a clear paint is applied by a wet-on-wet method, and 2 coats 1
A method of heating and curing by a baking method is generally performed.

However, in the case of metallic color finish, since acrylic melamine resin paint is used as the clear paint, the resulting coating film has acid resistance, water resistance,
There is a problem in performance such as weather resistance and stain resistance, and improvement thereof has been desired.

On the other hand, in the case of solid color finish,
Alkyd melamine resin paints have been used, and in the past, a method of heating and curing by a one-coat, one-bake method has been generally performed, but recently, various finishes such as appearance, weather resistance, acid resistance, water resistance, and stain resistance have been obtained. As the demands on physical properties have become strict, a method of applying clear paint on a solid color has been proposed.

However, even with this method, satisfactory coating products have not yet been obtained, such as the above-mentioned various physical properties not reaching the satisfactory range and the recoat adhesion is poor.

As the top coat clear paint, a paint containing a vinyl-based copolymer having a hydrolyzable silyl group is
It is known that weather resistance and the like are good because of stable siloxane bond and siloxy bond. However, when the polyol component is contained, water marks are likely to be formed on the surface of the coating film especially in the accelerated weathering test.

A blend system of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol is superior in heat-curing property and appearance to a system in which an acrylic polyol is not blended, and is relatively high. Since the amount of the compound having a hydrolyzable silyl group, which is an expensive raw material, can be reduced, there is an advantage that it leads to cost reduction as a curable composition, but on the other hand, there is a drawback that water resistance and acid resistance are slightly inferior. is there.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is not only excellent in acid resistance, hardness and appearance, but also in weather resistance, recoat adhesion and the like. It is intended to provide a curable composition for a coating having an excellent balance of coating film physical properties and a coated article obtained by applying the curable composition.

[0014]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that not only excellent resistance to acid, hardness, and appearance but also coating film such as weather resistance and recoat adhesion. It has been found that a curable composition for paints having an excellent balance of physical properties and a coated article obtained by applying the composition can be obtained, and the present invention has been completed.

That is, the curable composition for coating composition of the present invention comprises (A) a carboxyl group-free main chain consisting essentially of a vinyl-based copolymer chain and having main chain terminals and / or side chains. It has at least one hydrolyzable silyl group represented by the following general formula (1) in one molecule and has a silicon equivalent of 300 to 3
A vinyl-based copolymer having a molecular weight of 10,000 and an alcoholic hydroxyl group in the same molecule at the main chain terminal and / or side chain and an alcoholic hydroxyl group equivalent of 400 to 15,000.

Embedded image (In the formula, R ¹ and R ² are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group, and a is 0, 1 or 2. ), (B) The carboxyl group-containing main chain is substantially composed of a vinyl-based copolymer chain, and a main chain terminal and / or a side chain has a hydrolyzable silyl group represented by the following general formula (2). It has at least one in the molecule and has a silicon equivalent of 1,000 to 1.
A vinyl-based copolymer having a molecular weight of 5,000, an alcoholic hydroxyl group in the same molecule at the main chain terminal and / or a side chain, and an alcoholic hydroxyl group equivalent of 200 to 1,000.

Embedded image (In the formula, R ³ and R ⁴ are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group, and b is 0, 1 or 2. (C) Hydroxyl-containing compound having no hydrolyzable silyl group (D) A compound containing a curing catalyst.

Further, the coated article of the present invention is a coated article obtained by applying a top coat clear coating material to a coating surface coated with a coating material containing a metallic powder and / or a coloring pigment, wherein the top coating clear coating material is As the composition, a composition containing the curable composition for coating material of the present invention as a main component can be used.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the components (A) to (D) and other components that can be blended in the present invention will be sequentially described.

Component (A) The component (A) in the present invention does not contain a carboxyl group, has a main chain substantially composed of a vinyl-based copolymer chain, and has a general formula () in the main chain terminal and / or side chain. 1):

Embedded image (In the formula, R ¹ and R ² are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group, and a is 0, 1 or 2. ) Is a polymer having at least one, preferably 2 to 10 hydrolyzable silyl groups in the molecule,
The silicon equivalent is 300 to 30,000, and the main chain end and / or side chain has an alcoholic hydroxyl group in the same molecule, and the alcoholic hydroxyl group equivalent is 400 to 1
It is a vinyl-based copolymer of 5,000.

Since the hydrolyzable silyl group-containing vinyl-based copolymer substantially consists of a vinyl-based copolymer chain, the cured product has excellent weather resistance, chemical resistance, etc., and the copolymer composition must be changed. This enables a wide range of resin designs from soft to hard. In this vinyl-based copolymer, usually about 50% (% by weight) or more, preferably about 60% or more, more preferably about 80% or more of the units constituting the main chain is composed of vinyl-based monomer units. Therefore, the vinyl copolymer as the component (A) may partially contain a urethane bond, a siloxane bond or the like in the main chain or side chain.

Examples of the hydrolyzable silyl group include the groups represented by the general formula (1) as described above.
In this formula, when the carbon number of R ¹ and R ² exceeds 10, the hydrolytic reactivity of the hydrolyzable silyl group decreases.

Specific examples of R ¹ include, for example, a methyl group,
Examples thereof include ethyl group, n-propyl group, isopropyl group, n-butyl group and isobutyl group.

Specific examples of the alkyl group for R ² include the same groups as the alkyl group for R ¹ , specific examples of the aryl group include, for example, phenyl group, and specific examples of the aralkyl group. , For example, a benzyl group.

The hydrolyzable silyl group represented by the general formula (1) may be contained at the terminal of the main chain of the vinyl copolymer as the component (A) or may be contained in the side chain. Often,
It may be contained in both the terminal and side chains of the main chain.

The hydrolyzable silyl group equivalent (= silicon equivalent, resin solid content (g) of the copolymer (A) containing 1 mol of hydrolyzable silyl group) in the copolymer (A) is 300-.
30,000 g / mole has excellent heat curability,
It is preferable from the viewpoint that a curable composition exhibiting acid resistance, weather resistance and the like can be obtained, and 350 to 20,000 g is preferable.
/ Mol is more preferable, 380 to 10,000
More preferably g / mol, 410-3,000
More preferably g / mol, 450-1,500
More preferably, it is g / mol.

Further, the alcoholic hydroxyl group equivalent in the copolymer (A) (resin solid content (g) of the copolymer (A) containing 1 mol of the alcoholic hydroxyl group) is 400 to 15,000.
It is 0 g / mol, preferably 430 to 12,000 g / mol, more preferably 450 to 7,500 g / mol, and more preferably 500 to 3,000 g / mol. When the alcoholic hydroxyl group equivalent is less than 400 g / mol, the acid resistance of the coating film formed by using the obtained curable composition is lowered, and 15,000.
When it exceeds g mol, the thermosetting property of the composition and the scratch resistance and impact resistance of the coating film are deteriorated.

If the molecular weight of the polymer as the component (A) is too small, the amount of the non-crosslinking component increases, so that the number average molecular weight is preferably 2,000 or more, and 2,500 to 2
More preferably, it is 30,000,
More preferably, it is 10,000. When the molecular weight exceeds 20,000, the viscosity becomes high, and as a result,
It will be necessary to reduce the solid content concentration during painting.

The polymer as the component (A) is generally composed of units from a vinyl-based monomer, units from a hydroxyl group-containing monomer, units from a hydrolyzable silyl group-containing monomer and the like.

The vinyl-based monomer is not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth). ) Acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoro Ethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, unsaturated polycarboxylic acids (maleic acid, fumaric acid, itaconic acid, etc.) and straight or branched alcohols having 1 to 20 carbon atoms Unsaturated polycarboxylic acid esters such as diesters or half esters; aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene and sodium styrenesulfonate; vinyl esters such as vinyl acetate and vinyl diallyl phthalate propionate; Allyl compounds; vinyl compounds containing nitrile groups such as (meth) acrylonitrile; vinyl compounds containing epoxy groups such as glycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate , Vinylpyridine, aminoethyl vinyl ether and other basic nitrogen atom-containing vinyl compounds; (meth) acrylamide, itaconic acid diamide, α-ethyl (meth) acrylamide, crotonami , Amide group-containing vinyl compounds such as maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine; vinyl methyl ether, chloride vinyl,
Other vinyl compounds such as vinylidene chloride, chloroprene, propylene, butadiene, isoprene, maleimide, N-vinylimidazole and the like can be mentioned.

The hydroxyl group-containing monomer is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2
-Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, 4-hydroxystyrene vinyltoluene, Aronix 5700 manufactured by Toagosei Kagaku Kogyo Co., Ltd., 4-hydroxystyrene, HE-1 manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
0, HE-20, HP-1 and HP-20 (all of which are acrylic acid ester oligomers having a hydroxyl group at the terminal), NOF CORPORATION's BLEMMER PP series (polypropylene glycol methacrylate), BLEMMER PE series (polyethylene) Glycol monomethacrylate), Blemmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Blemmer AP-400 (polypropylene glycol monoacrylate), Blemmer AE-350 (polyethylene glycol monoacrylate), Blemmer NKH-5050 (polypropylene glycol polytrimethylene monoacrylate). ) And Bremmer GLM
(Glycerol monomethacrylate), ε-caprolactone-modified hydroxyalkyl vinyl-based copolymerizable compound obtained by the reaction of hydroxyl group-containing vinyl compound and ε-caprolactone, and the like. Among them, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth)
The use of acrylate or 4-hydroxybutyl (meth) acrylate is preferable because it can impart excellent acid resistance and water resistance to the coating film.

Typical examples of the ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound include, for example, general formula (3):

[Chemical 6] (In the formula, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more) Placel FA-1 (R = H, n =, manufactured by Daicel Chemical Industries, Ltd.)
1), Placcel FA-4 (R = H, n = 4),
Placcel FM-1 (R = CH ₃ , n = 1), P
laccel FM-4 (R = CH ₃ , n = 4), UC
C Corp. TONE M-100 (R = H , n = 2) and TONE M-201 (R = CH 3, n = 1) , and the like.

These alcoholic hydroxyl group-containing vinyl copolymerizable compounds may be used alone or in combination of two or more kinds.

The amount of the alcoholic hydroxyl group-containing vinyl copolymerizable compound used is 5 to 50% of the total amount of the copolymerization components,
It is preferably 7 to 35%. When the amount of such a monomer used is less than 5%, the resulting composition tends not to exhibit sufficient curability, and when it exceeds 50%, a curable composition is used. The water resistance and acid resistance of the coating film tend to decrease.

The hydrolyzable silyl group-containing monomer is not particularly limited, and the following examples can be given.
That is,

[Chemical 7]

Embedded image And the like, and also includes (meth) acrylate having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond. These alkoxysilyl group-containing vinyl-based copolymerizable compounds may be used alone or in combination of two or more.

The amount of the hydrolyzable silyl group-containing monomer used is 5 to 50% of the total amount of the copolymerization components, preferably 5 to 50%.
It is preferably 35%. When the amount of such a monomer used is less than 5%, the acid resistance of the coating film formed using the resulting curable composition tends to be insufficient, and when it exceeds 50%, The storage stability of the curable composition tends to decrease.

As the method for producing the polymer as the component (A), generally, the above-mentioned hydrolyzable silyl group-containing monomer, vinyl monomer and hydroxyl group-containing monomer are copolymerized, for example, JP-A-54-36395 and JP-A-57-57395. For example, the method shown in JP-A-55953 and the like are preferable, and the solution polymerization method using an azo radical initiator such as azobisisobutyronitrile is preferable from the viewpoint of easy handling and the like.

If necessary, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ
-Mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane,

Embedded image The molecular weight may be adjusted using a chain transfer agent such as. In particular, if a chain transfer agent having a hydrolyzable silyl group in the molecule, such as γ-mercaptopropyltrimethoxysilane, is used, the hydrolyzable silyl group can be introduced into the terminal of the vinyl copolymer to be produced. .

The polymerization solvent used for the solution polymerization is
Hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, n-butyl alcohol, etc.), ethers (ethyl cellosolve, Non-reactive solvents such as butyl cellosolve, cellosolve acetate, etc.) and ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, acetone, etc.). There is no.

These polymerization solvents may be used alone,
Two or more kinds may be used in combination, but particularly when a vinyl-based monomer (A) is obtained by polymerizing a vinyl-based monomer containing a hydrolyzable silyl group and a vinyl-based monomer containing an alcoholic hydroxyl group. When the amount of all the copolymerizable compounds constituting the vinyl-based copolymer is 100 parts by weight (hereinafter referred to as "part"), the amount of alcoholic solvent such as methanol or butyl alcohol in the solvent composition is 1 part. If it is less than the above range, gelation may occur during polymerization. Therefore, the solvent composition used for obtaining the copolymer (A) by polymerizing the vinyl monomer containing a hydrolyzable silyl group and the vinyl monomer containing an alcoholic hydroxyl group contains an alcoholic solvent. It is preferable to use 1 to 30 parts of the vinyl copolymer based on 100 parts of all the copolymerizable compounds.

Further, the component (A) may contain a segment formed by a urethane bond or a siloxane bond in the main chain within a range not exceeding 50%, and other than a (meth) acrylic acid derivative. It may contain a segment derived from a polymer compound.

Component (B) In the component (B) of the present invention, the carboxyl group-containing main chain is substantially composed of a vinyl copolymer chain, and the main chain terminal and / or side chain has the general formula (2). :

Embedded image (In the formula, R ³ and R ⁴ are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group, and b is 0, 1 or 2. ) Has at least one, preferably 2-10, hydrolyzable silyl groups in the molecule, has a silicon equivalent of 1,000-15,000, and has a main chain terminal and / or a side chain. A vinyl-based copolymer having an alcoholic hydroxyl group in the same molecule and having an alcoholic hydroxyl group equivalent of 200 to 1,000.

Since the hydrolyzable silyl group-containing vinyl copolymer is substantially composed of a vinyl copolymer chain, the weather resistance and chemical resistance of the cured product are excellent, and the copolymer composition should be changed. This enables a wide range of resin designs from soft to hard. In the vinyl copolymer, about 50% or more, preferably about 60% or more, and more preferably about 80% or more of the units constituting the main chain are units of vinyl monomers. Therefore, the vinyl copolymer as the component (B) may partially contain a urethane bond, a siloxane bond, or the like in the main chain or side chain.

Examples of the hydrolyzable silyl group include the groups represented by the general formula (2) as described above.
In this formula, when the carbon number of R ³ and R ⁴ exceeds 10, the hydrolytic reactivity of the hydrolyzable silyl group is lowered.

Specific examples of R ³ include, for example, a methyl group,
Examples thereof include ethyl group, n-propyl group, isopropyl group, n-butyl group and isobutyl group.

Specific examples of the alkyl group for R ⁴ include the same groups as the alkyl group for R ³ , specific examples of the aryl group include phenyl group, and specific examples of the aralkyl group. , For example, a benzyl group.

The hydrolyzable silyl group represented by the general formula (2) may be contained in the terminal of the main chain of the vinyl copolymer as the component (B) or may be contained in the side chain. Often,
It may be contained in both the terminal and side chains of the main chain.

The polymer as the component (B) generally comprises a unit derived from a vinyl monomer, a unit derived from a hydroxyl group-containing monomer, and a unit derived from a hydrolyzable silyl group-containing monomer.
It is composed of a derivative of (meth) acrylic acid.

The vinyl monomer is not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth). ) Acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoro Ethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, unsaturated polycarboxylic acids (maleic acid, fumaric acid, itaconic acid, etc.) and straight or branched alcohols having 1 to 20 carbon atoms Unsaturated polycarboxylic acid esters such as diesters or half esters; aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene and sodium styrenesulfonate; vinyl esters such as vinyl acetate and vinyl diallyl phthalate propionate; Allyl compounds; vinyl compounds containing nitrile groups such as (meth) acrylonitrile; vinyl compounds containing epoxy groups such as glycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate , Vinylpyridine, aminoethyl vinyl ether and other basic nitrogen atom-containing vinyl compounds; (meth) acrylamide, itaconic acid diamide, α-ethyl (meth) acrylamide, crotonami , Amide group-containing vinyl compounds such as maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine; vinyl methyl ether, chloride vinyl,
Other vinyl compounds such as vinylidene chloride, chloroprene, propylene, butadiene, isoprene, maleimide, N-vinylimidazole and the like can be mentioned.

The hydroxyl group-containing monomer is not particularly limited, and for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2
-Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, 4-hydroxystyrene vinyltoluene, Aronix 5700 manufactured by Toagosei Kagaku Kogyo Co., Ltd., 4-hydroxystyrene, HE-1 manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
0, HE-20, HP-1 and HP-20 (all of which are acrylic acid ester oligomers having a hydroxyl group at the terminal), NOF CORPORATION's BLEMMER PP series (polypropylene glycol methacrylate), BLEMMER PE series (polyethylene) Glycol monomethacrylate), Blemmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Blemmer AP-400 (polypropylene glycol monoacrylate), Blemmer AE-350 (polyethylene glycol monoacrylate), Blemmer NKH-5050 (polypropylene glycol polytrimethylene monoacrylate). ) And Bremmer GLM
(Glycerol monomethacrylate), ε-caprolactone-modified hydroxyalkyl vinyl-based copolymerizable compound obtained by the reaction of hydroxyl group-containing vinyl compound and ε-caprolactone, and the like. Among them, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth)
The use of acrylate or 4-hydroxybutyl (meth) acrylate is preferable because it can impart excellent acid resistance and water resistance to the coating film.

Typical examples of the ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound include those represented by the general formula (3):

Embedded image (In the formula, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more) Placel FA-1 (R = H, n =, manufactured by Daicel Chemical Industries, Ltd.)
1), Placcel FA-4 (R = H, n = 4),
Placcel FM-1 (R = CH ₃ , n = 1), P
laccel FM-4 (R = CH ₃ , n = 4), UC
C Corp. TONE M-100 (R = H , n = 2) and TONE M-201 (R = CH 3, n = 1) , and the like.

These alcoholic hydroxyl group-containing vinyl copolymerizable compounds may be used alone or in combination of two or more kinds.

The hydrolyzable silyl group-containing monomer is not particularly limited, and the following examples can be given.
That is,

[Chemical 12]

Embedded image And the like, and also includes (meth) acrylate having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond. These alkoxysilyl group-containing vinyl-based copolymerizable compounds may be used alone or in combination of two or more.

Specific examples of the carboxyl group-containing vinyl polymerizable compound include α, β-ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, or their anhydrides and carbons. Number 1-20
Half-esters with linear or branched alcohols are mentioned.

As a method for synthesizing the component (B), a solution polymerization method using a peroxide radical initiator such as t-butylperoxyacetate or an azo radical initiator such as azobisisobutyronitrile, It is preferable because it can be easily synthesized.

If necessary, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ
-Mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane,

Embedded image The molecular weight may be adjusted using a chain transfer agent such as. In particular, if a chain transfer agent having a hydrolyzable silyl group in the molecule, such as γ-mercaptopropyltrimethoxysilane, is used, the hydrolyzable silyl group can be introduced into the terminal of the vinyl copolymer to be produced. .

The polymerization solvent used for the solution polymerization is
Hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, n-butyl alcohol, etc.), ethers (ethyl cellosolve, Non-reactive solvents such as butyl cellosolve, cellosolve acetate, etc.) and ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, acetone, etc.). There is no.

These polymerization solvents may be used alone,
Two or more kinds may be used in combination, but particularly when a vinyl-based copolymer (B) is obtained by polymerizing a vinyl-based monomer containing a hydrolyzable silyl group and a vinyl-based monomer containing an alcoholic hydroxyl group. When the amount of all copolymerizable compounds constituting the vinyl-based copolymer is 100 parts and the amount of alcoholic solvent such as methanol or butyl alcohol in the solvent composition is less than 1 part, gelation occurs during polymerization. Sometimes. Therefore, the solvent composition used for obtaining the copolymer (B) by polymerizing the vinyl monomer having a hydrolyzable silyl group and the vinyl monomer having an alcoholic hydroxyl group contains an alcoholic solvent. It is preferable to use 1 to 30 parts of the vinyl copolymer based on 100 parts of all the copolymerizable compounds.

The molecular weight of the component (B) is not particularly limited, but the physical properties of the cured coating film such as durability expected from the curable composition of the present invention (hereinafter referred to as "coating film physical properties"). The number average molecular weight is preferably 1,500 to 40,000, more preferably 3,000 to 25,000.

On the other hand, the silicon equivalent of the component (B) is 1,0
It is limited to 00 to 15,000. 2,200-
It is preferably 12,500, and particularly from 2,400 to
It is preferably 10,000. When this silicon equivalent is less than 1,000, the storage stability of the curable composition tends to decrease.

On the other hand, when it exceeds 15,000, the curability of the composition is not always sufficient.

Further, the alcoholic hydroxyl group equivalent of the component (B) is limited to 200 to 1,000. Further 300 ~
It is preferably 900, and particularly preferably 350 to 800. This alcoholic hydroxyl group equivalent is 20
When it is less than 0, water marks are likely to be formed during the weather resistance test.
On the other hand, when it exceeds 1,000, the curability of the composition is not always sufficient.

The acid value is preferably 5 to 120 mgKOH / g, more preferably 10 to 80 mgKOH / g, and further preferably 20 to 60 mgKOH / g. When the acid value is less than 5 mgKOH / g, the effect of the present invention is not sufficiently exhibited,
When it exceeds gKOH / g, the storage stability of the composition decreases.

The proportion of the component (B) in 100 parts of the mixture of the component (A) and the component (B) is preferably 1 to 90% (component A: 10 to 99%).

Component (C) The hydroxyl group-containing compound that is the component (C) is a hydroxyl group-containing compound that does not have a hydrolyzable silyl group, and may or may not be a vinyl-based copolymer. From the viewpoint of the durability of the film obtained from the composition, a hydroxyl group-containing copolymer of vinyl monomer (hereinafter referred to as "acrylic polyol").
It is preferable).

The acrylic polyol can be obtained, for example, by copolymerizing a hydroxyl group-containing vinyl monomer with another copolymerizable vinyl monomer.

The hydroxyl group-containing vinyl monomer contained as the above-mentioned copolymerization component is not particularly limited and may be, for example, 2
-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, 4 -Hydroxystyrene vinyltoluene, Aronix 5700 manufactured by Toagosei Chemical Industry Co., Ltd., 4-hydroxystyrene, HE-10, HE-2 manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
0, HP-1 and HP-20 (both of which are acrylic acid ester oligomers having a hydroxyl group at the terminal), NOF CORPORATION Blemmer PP series (polypropylene glycol methacrylate), Blemmer PE series (polyethylene glycol monomethacrylate). , Blemmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Blemmer A
P-400 (polypropylene glycol monoacrylate), Bremmer AE-350 (polyethylene glycol monoacrylate), Bremmer NKH-5050
(Polypropylene glycol polytrimethylene monoacrylate) and Blemmer GLM (glycerol monomethacrylate), and ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound obtained by the reaction of hydroxyl group-containing vinyl compound and ε-caprolactone.

These hydroxyl group-containing vinyl monomers may be used alone or in combination of two or more.

There are no particular restrictions on the other vinyl-based monomers copolymerizable with these hydroxyl group-containing vinyl-based monomers. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) ) Acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, Benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, unsaturated polycarboxylic acid (maleic acid, fumaric acid, itako Unsaturated polycarboxylic acid ester such as a diester or a half ester of an acid or the like) with a linear or branched alcohol having 1 to 20 carbon atoms; aromatic carbonization such as styrene, α-methylstyrene, chlorostyrene or sodium styrenesulfonate Hydrogen-based vinyl compounds; vinyl acetate and vinyl compounds such as vinyl acetate and vinyl diallyl phthalate propionate; nitrile group-containing vinyl compounds such as (meth) acrylonitrile; epoxy group-containing vinyl compounds such as glycidyl (meth) acrylate; dimethylaminoethyl ( Basic nitrogen atom-containing vinyl compounds such as (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, vinyl pyridine, aminoethyl vinyl ether; (meth) acrylamide, itaconic acid diester Amide, α-ethyl (meth) acrylamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine, etc. Amide group-containing vinyl compound;

These vinyl-based monomers copolymerizable with the hydroxyl group-containing vinyl-based monomers may be used alone or in combination of two or more.

The resulting acrylic polyol may contain less than 50% of segments formed by urethane bonds or siloxane bonds in its main chain.

The acrylic polyol is preferably prepared by solution polymerization using a radical initiator. In solution polymerization, a chain transfer agent such as n-dodecyl mercaptan is optionally used to control the molecular weight.

A non-reactive solvent is used as the polymerization solvent, but it is not particularly limited.

The acrylic polyol may be used alone or in combination of two or more kinds.

When the hydroxyl group-containing compound as the component (C) is not a vinyl type copolymer, specific examples thereof include organic polyols such as polycaprolactone polyol, polyvalerolactone polyol and polyhexamethylene carbonate polyol. Can be mentioned.

The acrylic polyol is preferably a non-aqueous dispersed polymer from the viewpoints of breaking stress and elongation of the film, and from the viewpoint of adjusting the rheology of the coating material.

Non-aqueous dispersed polymers are described in the literature (KEJ Barrett, Dispersion Polymerization in Or
ganic Media, Jhon Wiley & Sons. London. (1975)), it is a polymer that is stably dispersed in an organic medium. This polymer is composed of (1) a core part and (2) an arm part, both of which are
Covalently bonded by the reaction of the carboxylic acid and the epoxy group.

The core part consists of a polymer dispersed in an organic medium. The arm portion (2) itself is a polymer that is soluble in an organic medium and is a stabilizer that forms a steric barrier by binding to the core portion (1).

The core portion (1) has a number average molecular weight of 15,0.
From 100 to 300,000 macromolecular polymers,
The arm portion (2) is a stabilizer that forms a steric barrier, and is a macromer chain attached to the core portion (1).

The core part (1) is composed of a copolymer of vinyl monomers. Examples of this monomer are not particularly limited, and examples thereof include acrylic acid and methacrylic acid, and their alkyl esters, hydroxyalkyl esters, allyl esters, glycidyl esters; styrene; acrylonitrile and the like.

The arm portion (2) attached to the core portion (1) comprises 90 to 10% of the dispersed polymer, preferably 20 to 50%. When the proportion of arms exceeds 90% of the dispersed polymer, it is difficult to obtain a cured product having durability. On the other hand, if it is less than 10%, the viscosity of the dispersed polymer may be increased, or the stability of the dispersed polymer may be deteriorated to cause precipitation.

The organic solvent-soluble polymer of the arm portion is one or more vinyl type monomers having a hydroxyl group in an amount of 5 to 30 parts, preferably 5 to 25 parts, and one or more vinyl type monomers having no hydroxyl group in an amount of 70 to 95. Parts, preferably 75-9
It consists of 5 parts. When the amount of the vinyl-based monomer having a hydroxyl group is less than 5 parts, the curability tends to decrease. On the other hand, if it exceeds 30 parts, the solubility in an organic solvent may be reduced, or the stability of the dispersion polymer may be insufficient.

When the hydroxyl group-containing compound which is the component (C) is not a non-aqueous dispersed polymer, the total of 1 R ¹ O—Si group and R ³ O—Si group in the components (A) and (B) is 1 It is preferable to mix the components (A), (B) and (C) so that the number of alcoholic hydroxyl groups in the component (C) is less than 0.1 per unit.

When the hydroxyl group-containing compound as the component (C) is a non-aqueous dispersed polymer, (A), (B)
The total number of R ¹ O—Si groups and R ³ O—Si groups in the component is less than 0.2, more preferably less than 0.1, in the arm portion of the component (C). Thus, it is preferable to mix the components (A) and (B) with the component (C).

In any case, if the number of alcoholic hydroxyl groups increases, the acid resistance and water resistance may decrease.

When the component (C) is not a non-aqueous dispersed polymer, its number average molecular weight is 1,000 to 25,000.
Is preferable, and 1,000 to 15,000 is more preferable. When the number average molecular weight is less than 1,000, weather resistance and water resistance may decrease, while when it exceeds 25,000, the compatibility of the compound may decrease.

When the component (C) is a non-aqueous dispersion polymer, the organic solvent-soluble polymer constituting the non-aqueous dispersion polymer has a number average molecular weight of 1,000 to 25,000.
Is preferable, and 1,000 to 15,000 is more preferable. When the number average molecular weight is less than 1,000, the stability of the dispersion polymer tends to be insufficient. On the other hand, when it exceeds 25,000, the polymer in the arm portion becomes difficult to dissolve in the organic medium.

The blending amount of the component (C) is 0 to 80 parts with respect to a total of 20 to 100 parts of the components (A) and (B). When the blending amount of the component (C) exceeds 80 parts, acid resistance, water resistance and the like may decrease. The preferred range is 0.001 to 60 parts, and the more preferred range is 0.1 to 50 parts.

Component (D) Examples of the curing catalyst of the component (D) used in the present invention include, for example, organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, tin octylate. Phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate,
Phosphoric acid or phosphoric acid ester such as diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acryl glycidyl ether, γ-glycidoxypropyltrimethoxysilane,
.gamma.-glycidoxypropyl triethoxysilane, .gamma.-glycidoxypropyl methyl dimethoxy _{silane, -CH 2 CH 2 -Si (OCH} 3) 3 Yuka Shell Epoxy Co., Ltd. of Kadeyura E, Yuka Shell Epoxy (strain ) Made of Epicoat 828, Epicoat 1
Addition reaction products of epoxy compounds such as 001 with phosphoric acid and / or monophosphoric acid ester; organic titanate compounds; organic aluminum compounds; organic zinc compounds; maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, Succinic acid, phthalic acid, trimellitic acid, pyromellitic acid and their acid anhydrides; acidic compounds such as dodecylbenzene sulfonic acid and paratoluene sulfonic acid, and their reaction products with amines (for example, KING INDUSTRIES) Made NAC
URE5225, NACURE5543, NACURE
5925 etc.); amines such as hexylamine, di-2-ethylhexylamine, N, N-dimethyldodecylamine, dodecylamine, DABCO, DBU, morpholine, diisopropanolamine; reaction products of these amines with acidic phosphate esters. And alkaline compounds such as sodium hydroxide and potassium hydroxide. Such curing catalysts may be used alone or in combination of two or more.

Among these curing catalysts, a sulfonic acid compound blocked with a nitrogen-containing compound, the nitrogen-containing compound being a primary or secondary amine compound having an average of one or more hydroxyl groups in one molecule. Or one or more compounds selected from morpholine or oxazolidine, for example, KING INDUSTR
IES) NACURE 5225, NACURE 55
43 and NACURE 5925 are preferable in terms of the balance between curability during baking and storage stability at room temperature. Further, these compounds can be used in combination with the above-mentioned organotin compound, phosphoric acid, phosphoric acid ester or the like.

Examples of these sulfonic acid compounds include:
Dodecylbenzene sulfonic acid, paratoluene sulfonic acid, 1-naphthalene sulfonic acid, 2-naphthalene sulfonic acid and the like can be mentioned.

Further, examples of these nitrogen-containing compounds include:
1-amino-2-propanol, monoethanolamine, diethanolamine, 2- (methylamino) ethanol, 2-dimethylethanolamine, 2-amino-2
-Methyl-1-propanol, diisopropanolamine, 3-aminopropanol, 2-methylamino-2-
Methyl propanol, morpholine, oxazolidine,
4,4-dimethyloxazolidine, 3,4,4-trimethyloxazolidine and the like can be mentioned.

The equivalent ratio of these nitrogen-containing compound and sulfonic acid compound is preferably 1: 0.75 to 3.0, more preferably 1: 1.0 to 2.0.
If this ratio is less than 1: 0.75, storage stability and appearance at room temperature may deteriorate. Moreover, this ratio is 1: 3.
If it exceeds 0, the curability during baking will be poor, or the yellowing of the coating film will become strong.

The amounts of component (D) used are (A), (B),
(C) 0.0001 to 1 with respect to 100 parts of total resin solids
It is 0 part, preferably 0.05 to 10 parts. If the amount of component (D) used is less than 0.0001 part, the curability tends to decrease, and if it exceeds 10 parts, the appearance of the coating film tends to decrease.

Others The curable composition of the present invention comprises the component (A), the component (B),
In addition to the component (C), an amino resin is used as the component (A) and the component (B).
3 to 100 parts of the total resin solid content of the component and the component (C)
Less than 0 part, preferably less than 15 parts, particularly preferably less than 5 parts can be added. Amino resin content of 30
If it is more than 10 parts, the acid resistance will decrease.

The amino resin used in the present invention includes:
Examples include amino resins (methylolated amino resins such as melamine resin, urea resin and guanamine resin) obtained by reacting an amino component such as melamine, urea, benzoguanamine, glycol urea, acetoguanamine and dicyandiamide with an aldehyde. Aldehydes include:
There are formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like.

Among the above, melamine resin is preferably used from the viewpoints of improving the finished appearance and curability.

Further, the amino resin (for example, methylolated amino resin) is replaced with methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, 2
Those further etherified with an alcohol such as -ethylbutanol and 2-ethylhexanol can also be used. Specific examples of the amino resin include Uban 20SE, 20SE-60, Uban 128, Uban 220, Uban 225, Uban 20SB, Uban 20SE-60, Uban 21R manufactured by Mitsui Toatsu Chemicals, Inc.
U-Van 22R, U-Van 122, U-Van 28-6
0, Yuban 20HS, Yuban 2028, Yuban 2
02, n-butylated melamine resin such as Uban 120,
Isobutylated melamine such as Uban 62, Uban 69-1, Uban 169, Uban 2061 and Uban 1
Butylated urea resins such as 0S-60 and Uban 10R, Cymel 303 and Cymel 23 manufactured by Mitsui Cytec Co., Ltd.
2, Cymel 370, Cymel 325, Cymel 23
6, Cymel 738, Cymel 771, Cymel 32
7, Cymel 703, Cymel 701, Cymel 26
6, Cymel 267, Cymel 285, Cymel 23
5, Cymel 238, Cymel 1141, Cymel 27
2, Cymel 254, Cymel 202, Cymel 115
6, Cymel 1158, Cymel 300, Cymel 30
1, melamine resins such as Cymel 350 and Cymel 736, and the like, and alkyletherified melamine resins such as Cymel 235, Cymel 238, and Cymel 1158 are preferable from the viewpoint of curability.

In the composition of the present invention, organopolysiloxane silanols, tetraalkoxysilanes, alkyltrialkoxysilanes, partial hydrolysates thereof, amino resins such as melamine and the like (A), ( It may be added in an amount of preferably 50 parts or less, more preferably 30 parts or less, based on 100 parts of the total resin solid content of B) and (C). If more than 50 parts of the organopolysiloxane silanol is added, the film becomes brittle. In addition, if more than 50 parts of tetraalkoxysilane, alkyltrialkoxysilane, or a partial hydrolyzate thereof is added, the compatibility will decrease or the internal stress will increase. If more than 50 parts of an amino resin such as melamine is added, the acid resistance is rather lowered.

A hydrolyzable ester compound as a dehydrating agent and an alkyl alcohol as a solvent may be added to the composition of the present invention.

Examples of dehydrating agents include methyl orthoformate,
Examples thereof include ester compounds such as ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, ethyl silicate (tetraethoxysilane) and methyl silicate (tetramethoxysilane), and hydrolyzable ester compounds such as methyltrimethoxysilane.

These dehydrating agents are (A), (B), (C)
It may be added at the time of polymerizing the components or after the polymerization. The addition amount of the dehydrating agent is 70 parts or less, preferably 5 parts, based on 100 parts of the total resin solid content of (A), (B) and (C).
It is 0 part or less, more preferably 20 parts or less.

When the amount of the dehydrating agent added exceeds 70 parts, the stabilizing effect of the alkoxysilyl group is almost unchanged, and it becomes difficult to form a high solid.

Examples of the alkyl alcohol used as the solvent include alcohols having an alkyl group having 1 to 10 carbon atoms. Specific examples of such alcohol include, for example, methyl alcohol, ethyl alcohol and n-.
Propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol, cellosolve and the like can be mentioned.

The amount of the alcohol used is not particularly limited, but is usually 70 parts or less, preferably 50 parts or less, and more preferably 100 parts by weight of the total resin solid content of (A), (B) and (C). Is 20 parts or less, and when using a solvent alone without using a dehydrating agent, it is usually 0.5 to 70 parts, preferably 1 to 50 parts, and more preferably 2 to 20 parts. If the amount of the alcohol solvent is less than 0.5 part, there is almost no effect of stabilizing the alkoxysilyl group, and if it exceeds 70 parts, high solidification becomes difficult.

When the alcohol and the dehydrating agent are used in combination, the storage stability is remarkably improved as compared with the case where the composition comprising the components (A), (B), (C) and (D) is stored. It The amount of solvent that exhibits such an effect is
The composition of the present invention varies depending on the molecular weights and compositions of the components (A), (B), (C) and (D), and cannot be specified unconditionally, but the solid content concentration required for the composition to be practically It may be prepared so as to have a viscosity.

When the composition of the present invention is used as a top coat, the weather resistance can be further improved by blending an ultraviolet absorber and a light stabilizer, particularly by using them together. As the ultraviolet absorber, conventionally known ones can be widely used and, for example, benzophenone-based, triazole-based, phenylsalicylate-based, diphenylacrylate-based, acetophenone-based ultraviolet absorbers and the like are preferable.

As the light stabilizer, those publicly known can be widely used, and for example, bis (2,2,6-tetramethyl-
4-piperidyl) sebacate, bis (1, 2, 2, 6,
6-pentamethyl-4-piperidyl) sebacate, 2-
Bis (1,2,2,2,3-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate
6,6-pentamethyl-4-piperidyl), 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-butanetetracarboxylate and the like can be mentioned. These may be used alone,
More than one species may be used in combination.

The content of the ultraviolet absorber is usually 0.1 to 10 parts, preferably 1 to 100 parts of the solid content of the composition.
~ 5 parts. The amount of the light stabilizer is usually 0.1 to 10 parts, preferably 1 to 100 parts of the solid content of the composition.
~ 5 parts.

When the composition of the present invention is used as a top coat clear paint, additives such as a diluent, an anti-cratering agent, a leveling agent, etc., depending on the application; nitrocellulose,
Fibrous compounds such as cellulose acetate butyrate;
A resin such as an epoxy resin, a melamine resin, a vinyl chloride resin, a chlorinated polypropylene, a chloride rubber, and polyvinyl butyral may be added.

The composition of the present invention has low toxicity and can be made into a high solid having a solid content concentration of 50 to 70%. For example, it is applied to a substrate by a method such as spray coating and then at about 80 to 160 ° C. It is cured by heating or the like to be a cured coating film having excellent chemical resistance such as acid resistance, weather resistance, scratch resistance and the like.

The composition of the present invention is useful for coating automobiles, building exteriors, industrial machines, steel furniture, plastics, etc., and is particularly useful as a top coating for automobiles. An example of applying the curable composition according to the present invention will be described below. First, a paint containing a metallic powder and / or a color pigment is applied to an object to be coated.

Next, a top coat clear paint containing the curable composition of the present invention as a main component is applied to the coated surface.

In the above case, the paint (base coat) containing the metallic powder and / or the coloring pigment is not particularly limited, and examples thereof include aminoalkyd resin, oil-free alkyd resin, thermosetting acrylic resin, thermosetting urethane resin, and nitrified cotton. Lacquer, modified acrylic lacquer, slate acrylic lacquer, room temperature curing urethane resin, acrylic enamel resin, oxidation curing alkyd resin, oxidation curing modified (CAB etc.) alkyd resin, room temperature or heat curing type fluororesin, hydrolyzable silyl group containing resin It is possible to use, for example, a composition containing the composition of the present invention or a mixture thereof as a main component and containing metallic powder or a coloring pigment.

The coating containing the metallic powder and / or the coloring pigment may be any of a solution type coating using an organic solvent as a medium, a non-aqueous dispersion coating, a multi-component coating, a powder coating, a slurry coating, an aqueous coating and the like. Type of paint may be used.

The metallic powder and color pigment are not particularly limited, and those conventionally used can be used. As the metallic powder, for example, aluminum powder, copper powder, mica powder can be used, and as the coloring pigment, for example, organic pigments such as phthalocyanine blue, toluidine red, benzidine yellow, titanium oxide, carbon black, red iron oxide, etc. Inorganic pigments can be used. These metallic powders and color pigments may be used alone or in combination of two or more as required.

If the base coat is blended with the above-mentioned ultraviolet absorber or light stabilizer, the weather resistance of the coated article can be further improved.

Further, the coating composition containing the metallic powder and / or the color pigment may be blended with the above-mentioned silicon compound in order to improve the adhesion between the coating film and the top coat clear coating film.

In this case, the blending amount of the silicon compound is such that the coating material 1 containing the metallic powder and / or the color pigment is used.
It is usually 50 parts or less, preferably 20 parts or less with respect to 00 parts.

The coated article according to the present invention is obtained by further applying a top coat clear coating on the coated surface coated with a base coat. For example, the coating containing the metallic powder and / or the color pigment is coated on the coated article. After setting for a few minutes, top coat clear paint is applied by the wet-on-wet method and heat-cured in the two-coat one-bake method, or a paint containing metallic powder and / or color pigment is applied and heated, It can be produced by a two-coat, two-bake system or the like in which a top coat clear paint is applied after curing and then heated and cured.

The top coat clear coating composition is applied by various conventionally known methods such as dipping, spraying, brush coating, a method using a roll coater or a flow coater, and then 30 ° C. or higher, preferably 55 to 350. ℃
It can be heated to cure.

The thickness of the coating film of the coated product cannot be unconditionally specified because it depends on the application, but metallic powder and / or
Alternatively, the thickness of the coating film containing the color pigment is preferably in the range of 10 to 30 μm from the viewpoint of hiding property, and the thickness of the top coat clear coating film is 20 to 5 from the viewpoint of durability and the like.
The range of 0 μm is preferable.

[0121]

As described in detail above, the curable composition for paints of the present invention has low toxicity, good storage stability and good recoat adhesion, and a coated product obtained by applying this composition. Has excellent curability, appearance, acid resistance, and weather resistance.

[0122]

EXAMPLES Next, a curable composition for coating materials of the present invention, and
A coated article obtained by applying it will be described more specifically based on Examples. However, the invention is not limited to these examples.

Synthesis Example 1 [(A-1 to 3) (A'-1)
(B-1 and 2) (B'-1 and 2) and (C-1)
[Synthesis] [Part 2] in [Table 1] below in a reactor equipped with a stirrer, a thermometer, a reflux machine, a nitrogen gas introducing pipe, and a dropping funnel.
Was charged, the temperature was raised to 105 ° C. while introducing nitrogen gas, and then the mixed solution of [Part 1] was added dropwise at a constant rate over 5 hours.

Next, the mixed solution of [Part 3] was added dropwise thereto at a constant rate over 1 hour. After that, continue to 105 ℃
After stirring for 2 hours at room temperature, it was cooled to room temperature. Finally, the mixed solution of [Part 4] was added and stirred.

The solid content concentration of the obtained solution, the number average molecular weight of the copolymer (measured by gel permeation chromatography (GPC)), the silicon equivalent and the alcoholic hydroxyl group equivalent, and the acid value are also shown in [Table 1]. .

[0126]

[Table 1] .

Synthesis Example 2 (of the non-aqueous dispersed hydroxyl group-containing polymer (C-2) component
Synthetic. (See [Table 2])

[Table 2] [Part 1] in [Table 2] was charged into a reaction vessel and heated to a reflux temperature (97 ° C). Next, add [Part 2],
Immediately, [Part 3] and [Part 4] were added at a constant rate over 225 minutes.

Initially, it was transparent, but shortly after the addition of [Part 3] and [Part 4], it became a pale blue color and became cloudy white after 40 minutes.

[Portion 5] was then added at a constant rate for 30 minutes and held at that reflux temperature for an additional 90 minutes.

Finally, the excess solvent was removed to obtain a solid content of 6
A stable dispersion was obtained which was 3.4% cloudy but did not separate into layers.

The polymer obtained has a Stormer viscosity of 7
At 6 KU, the average particle size was 300 nm.

The "solution consisting of an organic solvent-soluble polymer" in the raw material (part 1) was prepared by synthesizing the monomer shown in () in the solvent shown in (). This polymer forms the arm (2).

Further, methacrylic acid in the raw material (part 3),
A polymer of 2-hydroxyethyl acrylate, methyl methacrylate, methyl acrylate, styrene and glycidyl methacrylate forms the core part (1).

Examples 1 to 7 and Comparative Examples 1 to 4 Component (A) [(A-1) to (A) obtained from the above synthesis example.
-3)], component (B) [(B-1), (B-2)],
Component (C) [(C-1), (C-2)] and (A'-1) and (B'-1), (B'-2) for comparison and control.
Was blended at a solid content ratio shown in [Table 3] below.

A leveling agent (L-1984-manufactured by Kusumoto Kasei Co., Ltd.) was used with respect to the total resin solid content in each Example or Comparative Example.
50) 0.4%, UV absorber Tinuvin 384 2%
%, And 1% of the light stabilizer TINUVIN 123 (all manufactured by Ciba Geigy).

This mixture was diluted with Solvesso 100 (petroleum aromatic solvent manufactured by Exxon Chemical Co., Ltd.) and adjusted to a viscosity of about 20 to 25 seconds with a Ford cup to obtain a clear coating for a top coat.

[0137] A mild steel sheet that had been degreased and phosphorylated was coated with an epoxyamide-based cationic electrodeposition primer for automobiles and an intermediate coat surfacer as a test piece, and a commercially available acrylic melamine resin coating (silver metallic base coat ) Was given.

Next, the clear coating composition for top coat was applied wet-on-wet, set for 20 minutes, and then baked at 140 ° C. for 30 minutes. The dry film thickness was about 15 μm for the base coat and about 50 μm for the top coat clear.

Physical properties such as appearance and recoat adhesion of the obtained coating film were evaluated by the following methods. The results are also shown in [Table 3].

Incidentally, (C-3) in [Table 3] is an example of the component (C) which is not a hydroxyl group-containing copolymer of a vinyl monomer (PLACCEL2 manufactured by Daicel Chemical Industries Ltd.).
10N (polycaprolactone diol, hydroxyl value = 11
2 mg KOH / g)).

(Appearance) Gloss and sharpness are visually evaluated comprehensively.は indicates good, Δ indicates normal, and × indicates poor.

(Recoat Adhesion) The above-mentioned base coat was applied to the obtained coated plate again in the same manner as the first time, and then each clear paint was applied wet-on-wet.
After setting for 1 minute, it was baked at 120 ° C. for 30 minutes. The adhesion of the coated plate was evaluated according to the cross-cutting method (2 mm × 2 mm × 25) of JIS K5400.

(Acid resistance) 0.5% of 40% sulfuric acid aqueous solution
c. Drop on a test plate using a pipette,
After heating at 0 ° C. for 30 minutes, the aqueous sulfuric acid solution was washed off with water, and the state of change of the coating film surface was observed and evaluated according to the following criteria. 10 points: No change from before test 9 points: Slight change observed 8 points: Circular traces left 7 points: Slight discoloration or blistering 5 points: Clear decrease in gloss or discoloration 1 Point: Dissolution of the film is observed.

(Accelerated weather resistance) In accordance with JIS K 5400, evaluation is carried out using a sunshine carbon arc lamp type weather resistance tester (manufactured by Suga Test Instruments Co., Ltd.). Test condition: Black panel temperature 63 ± 3 ° C., 18 minutes rain in 120 minutes After 1500 hours, it is visually evaluated as follows. ○: No abnormality ○ △: Adhesion of water marks is observed △: Decrease in gloss and adhesion of water marks are clearly observed.

(Pencil Hardness) The pencil hardness is evaluated according to JIS K 5400.

(Water resistance) A free clear film obtained by baking at 140 ° C. for 30 minutes was wrapped in an already precisely weighed 300-mesh stainless wire mesh (W ′ ₀ ) and weighed precisely (W ′ ₁ ).

This was immersed in water at 80 ° C. for 24 hours, then taken out, further immersed in acetone for 24 hours for extraction, dried, and precisely weighed (W ′ ₂ ). It was evaluated by. Water resistant gel fraction (%) = 100 × (W ′ ₂ −W ′ ₀ ) /
(W _'1 -W' ₀₎

[Table 3] As shown in [Table 3], it was found that this example is superior to the comparative example in the balance of appearance, recoat adhesion, acid resistance, weather resistance, and water resistance.

Examples 8 to 15 By changing the type of the curing catalyst (C), the difference between the gel fraction and the viscosity change rate was examined by the following method. The results are shown in [Table 4]. (Gel Fraction) A free clear film obtained by baking at 140 ° C. for 30 minutes was wrapped in a 300-mesh stainless steel wire mesh (W ₀ ) which had been precisely weighed, and precisely weighed (W ₁ ). This was immersed in acetone for 24 hours for extraction, dried, and precisely weighed (W ₂ ). The gel fraction was calculated according to the following formula. The larger the gel fraction value is near 100%, the higher the proportion of acetone insoluble matter in the film, and the greater the degree of crosslinking.

[0149]

[Equation 1] (Viscosity change rate) 100 g of clear paint for each top coat in a coated state is put in a 130 cc glass bottle, and the bottle is sealed and 5
Stored at 0 ° C. The viscosity at 23 ° C. was measured by a Ford cup, and the measured value was divided by the initial viscosity. The smaller the viscosity change rate, the better the storage stability.

[0150]

[Table 4] From the results shown in [Table 4], when a compound obtained by blocking a sulfonic acid with a nitrogen-containing compound is used as the curing catalyst of the component (C), the rate of change in viscosity is small, and storage stability and curability are excellent. You can see that

Claims (8)

[Claims] 1. A main chain of (A) does not contain a carboxyl group, and the main chain is substantially a vinyl copolymer chain, and the main chain terminal and / or
Or, it has at least one hydrolyzable silyl group represented by the following general formula (1) in one molecule in its side chain and has a silicon equivalent of 3
A vinyl copolymer having an alcoholic hydroxyl group of 100 to 30,000 and an alcoholic hydroxyl group in the same molecule at the main chain terminal and / or side chain and an alcoholic hydroxyl group equivalent of 400 to 15,000. ] (In the formula, R ¹ and R ² are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group, and a is 0, 1 or 2. ), (B) a carboxyl group is contained, the main chain is substantially composed of a vinyl copolymer chain, and a hydrolyzable silyl group represented by the following general formula (2) is added to the main chain terminal and / or side chain. It has at least one in one molecule, and the silicon equivalent is 1,000 to 1.
A vinyl-based copolymer having a molecular weight of 5,000 and an alcoholic hydroxyl group in the same molecule at the main chain terminal and / or side chain and an alcoholic hydroxyl group equivalent of 200 to 1,000. (In the formula, R ³ and R ⁴ are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group, and b is 0, 1 or 2. ), (C) a hydroxyl group-containing compound having no hydrolyzable silyl group, and (D) a curing catalyst. 2. A copolymer mixture comprising 10 to 99% by weight of the component (A) and 1 to 90% by weight of the component (B).
0 to 100 parts by weight, 0 to 80 parts by weight of the component (C), 0 of the component (D) per 100 parts by weight of the total solid content of the components (A), (B) and (C). .000
The composition according to claim 1, which is blended in an amount of 1 to 10 parts by weight. 3. The composition according to claim 1, wherein the component (C) is a copolymer of a hydroxyl group-containing vinyl monomer and another vinyl monomer. 4. The component (C) comprises 5 to 30 parts by weight of at least one vinyl-based monomer having a hydroxyl group and 70 to at least one vinyl-based monomer having no hydroxyl group.
And a number average molecular weight of 1,00
Obtained by dispersion polymerization of at least one vinyl monomer having a hydroxyl group and at least one vinyl monomer having no hydroxyl group in an organic solution containing 0 to 25,000 organic solvent-soluble polymer. 4. The composition according to claim 1, which is a non-aqueous dispersed polymer insoluble in the organic solution. 5. The composition according to any one of claims 1 to 4, wherein the component (A) contains an epoxy group. 6. The component (D) is a sulfonic acid compound blocked with a nitrogen-containing compound, and the nitrogen-containing compound is a primary or secondary compound having an average of one or more hydroxyl groups in one molecule. The composition according to claim 1, which is at least one selected from the group consisting of an amine compound, morpholine and oxazolidine. 7. An amino resin is further added to the component (A),
The composition according to any one of claims 1 to 6, which is blended in an amount of less than 30 parts by weight based on 100 parts by weight of the total resin solid content of the component (B) and the component (C). 8. A coated article obtained by applying a top coat clear paint on the surface to which a paint containing a metallic powder and / or a coloring pigment is applied, wherein the top coat clear paint is according to any one of claims 1 to 7. A coated article comprising the curable composition according to any one of the above as a main component.