JPH10158577A - Curable composition for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition useful as a top-coating material for automobile having an excellent acid resistance, water resistance, scratch resistance and weather resistance by using two specific kinds of vinyl copolymers, a curing catalyst and a hydrolyzable silicon compound as essential components. SOLUTION: The objective composition contains (A) 95-5 pts.wt. of a vinyl copolymer containing a vinyl copolymer chain as a main chain, having a hydrolyzable silyl group of the formula I (R<1> is a 1-10C alkyl; R<2> is H, a 1-10C alkyl, etc.; (a) is 0-2) and an epoxy group on the main chain terminal and the side chain and alcoholic hydroxyl groups on the main chain terminal and the side chain and having an alcoholic hydroxyl equivalent of 180-2,000g/mol, (B) 5-95 pts.wt. of a vinyl copolymer containing a vinyl copolymer chain as a main chain, having a hydrolyzable silyl group of the formula II (R<3> is a 1-10C alkyl; R<4> is H, a 1-10C alkyl, etc.; (b) is 0-2) on the main chain terminal and the side chain and free from alcoholic hydroxyl group, (C) 0.001-10 pts.wt. (based on 100 pts.wt. of A+B) of a curing catalyst and (D) a hydrolyzable silicon compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a curable composition for paints. More specifically, the present invention relates to a curable composition useful as a top coat used for, for example, automobiles, industrial machines, steel furniture, architectural exteriors, home appliances or plastics. Particularly, the present invention relates to a curable composition having excellent acid resistance, water resistance, abrasion resistance and weather resistance, which is useful as a top coating for automobiles.

[0002]

2. Description of the Related Art Conventionally, coating resins used for coating automobiles, building exteriors, industrial machines, steel furniture, plastics, etc. are mainly melamines such as alkyd melamine and acrylic melamine. Resin.

[0003] Such a melamine resin has a problem that harmful formalin is generated at the time of curing and the cured coating film is acid-resistant, so that it is affected by acid rain.

[0004] In particular, the problem of acid rain caused by air pollution in recent years has become serious, and phenomena such as etching, whitening, and spots on coating films have been observed.

In order to solve these problems, the present inventors have developed a vinyl copolymer having a hydrolyzable silyl group,
The use of a blend of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol in paint has been studied. As a result, they have found that these copolymers and blends solve the above-mentioned problems and become curable resins for paints having excellent acid resistance and weather resistance. -132977).

The characteristics of the vinyl copolymer having a hydrolyzable silyl group and the blend system of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol are such that the silyl group and the alcoholic hydroxyl group are stable. Since the siloxane bond or siloxy bond is formed and hardened, it is superior in acid resistance and weather resistance as compared with the case where a melamine resin such as acrylic melamine or alkyd melamine is used.

Further, the general formula (1):

[0008]

Embedded image

Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, and R ² is a hydrogen atom or a monovalent carbon atom selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group. A hydrogen group, a represents 0, 1 or 2), since the hydrolyzable silyl group is introduced into the main chain of the copolymer via a Si-C bond, it has excellent acid resistance and weather resistance. I have.

A blend system of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol is excellent in heat-curability and appearance and a relatively expensive raw material as compared with a system in which an acrylic polyol is not blended. Can reduce the amount of the compound having a hydrolyzable silyl group, which leads to a reduction in cost as a curable composition, but on the other hand, has a disadvantage in that the water resistance and the acid resistance are slightly reduced. Furthermore, in order to improve the compatibility between the vinyl copolymer having a hydrolyzable silyl group and the acrylic polyol, the molecular weight of each resin, the composition of the copolymerizable compound, and the blend ratio are limited.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies to obtain a low-cost curable composition having excellent heat curability, appearance, acid resistance, and water resistance. It was completed.

That is, according to the present invention, (A) the main chain is substantially composed of a vinyl copolymer chain, and the terminal of the main chain and / or the side chain has the general formula (1):

[0013]

Embedded image

Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, and R ² is a hydrogen atom or a monovalent carbon atom selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group. A represents a hydrogen group, a represents 0, 1 or 2), and has at least one hydrolyzable silyl group and an epoxy group in the molecule, and an alcoholic hydroxyl group at the terminal of the main chain and / or the side chain. In the same molecule, the alcoholic hydroxyl group equivalent is 180 to 2000 (g
/ Mol) of the vinyl copolymer (95 to 5 parts by weight (the same applies hereinafter)), (B) the main chain is substantially composed of the vinyl copolymer chain, and is located at the main chain terminal and / or the side chain. General formula (2):

[0015]

Embedded image

Wherein R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is a hydrogen atom or a monovalent carbon atom selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group. A hydrogen group, b represents 0, 1 or 2), a vinyl copolymer 5 having at least one hydrolyzable silyl group in the molecule, and having no alcoholic hydroxyl group in the same molecule. To 95 parts, a coating comprising (C) a curing catalyst and (D) a hydrolyzable silicon compound and containing 0.001 to 10 parts of component (C) based on 100 parts of components (A) and (B) in total The present invention relates to a curable composition for use.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The component used as component (A) in the present invention has a main chain substantially consisting of a vinyl copolymer chain, and has a compound represented by the general formula (1) at the terminal and / or side chain of the main chain. ):

[0018]

Embedded image

Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, and R ² is a hydrogen atom or a monovalent carbon atom selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an aralkyl group. A represents a hydrogen group, a represents 0, 1 or 2), and has at least one hydrolyzable silyl group and an epoxy group in the molecule, and an alcoholic hydroxyl group at the terminal of the main chain and / or the side chain. Having the same hydroxyl group equivalent in the same molecule as 180 to 2000 (g
/ Mol) is a vinyl copolymer.

The component used as the component (B) in the present invention has a main chain substantially consisting of a vinyl copolymer chain, and has a general formula (2) at the main chain terminal and / or the side chain.

[0021]

Embedded image

Wherein R ³ is an alkyl group having 1 to 10 carbon atoms, and R ⁴ is a hydrogen atom or a monovalent carbon atom selected from the group consisting of alkyl, aryl and aralkyl groups having 1 to 10 carbon atoms. A hydrogen group, b represents 0, 1 or 2), and is a vinyl copolymer having at least one hydrolyzable silyl group in the molecule and having no alcoholic hydroxyl group in the same molecule. is there.

In the above general formulas (1) and (2), a silicon atom bonded to a hydrolyzable group is bonded to the vinyl copolymer main chain via a Si—C bond. Accordingly, the vinyl copolymers (A) and (B) have excellent acid resistance and weather resistance.

Further, the vinyl copolymer (A),
In the blend system (B), the alcoholic hydroxyl group is introduced in the same molecule as the hydrolyzable silyl group and the epoxy group, and the alcoholic hydroxyl group-free vinyl copolymer having no alcoholic hydroxyl group Compared to using a blend system of acrylic polyol, the acid resistance of the cured product,
Excellent water resistance.

The amount of the alcoholic hydroxyl group in the vinyl copolymer (A) is such that the alcoholic hydroxyl equivalent is 1
It is preferably from 80 to 2000 g / mol.

The amount of the hydrolyzable silyl group in the vinyl copolymer (A) is such that the equivalent of the hydrolyzable silyl group is 380 to 30,000 g / mol. Preferred from the viewpoint of the nature
00 g / mol, more preferably 450 to 15 g / mol.
More preferably, it is 00 g / mol.

Further, the amount of the epoxy group in the vinyl copolymer (A) is such that the epoxy group equivalent is 100 to 1
The amount is preferably 500 g / mol from the viewpoint of curability, weather resistance, and finish, more preferably 150 to 1000 g / mol, and even more preferably 200 to 750 g / mol.

The ratio of the hydrolyzable silyl group to the alcoholic hydroxyl group in the vinyl copolymer (A) is such that one hydrolyzable silyl group and 0.1 to 3.0 alcoholic hydroxyl groups are used. It is heat-curable, acid-resistant,
It is preferable from the viewpoint of weather resistance and water resistance.

The molecular weight of the vinyl copolymer (A) having a hydrolyzable silyl group, an epoxy group and an alcoholic hydroxyl group as described above is the same as that of the present invention produced using the vinyl copolymer (A). The range of 1,000 to 30,000 is preferred from the viewpoint of the physical properties of the coating film of the curable composition for coatings,
The range of 2,000 to 25,000 is more preferred.

The units constituting the vinyl copolymer (A) include a unit having a hydrolyzable silyl group, a unit having an epoxy group, a unit having an alcoholic hydroxyl group, and a monomer serving as these units. Examples include units derived from copolymerizable monomers.

The unit having a hydrolyzable silyl group is formed, for example, by polymerizing an alkoxysilyl group-containing vinyl copolymerizable compound. Examples of the alkoxysilyl group-containing vinyl copolymerizable compound as described above include: For example

[0032]

Embedded image

[0033]

Embedded image

And (meth) acrylate having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond. These alkoxysilyl group-containing vinyl copolymerizable compounds may be used alone or in combination of two or more as necessary.

The unit having an alcoholic hydroxyl group is formed, for example, by polymerizing an alcoholic hydroxyl group-containing vinyl copolymerizable compound. Hydroxyethyl acrylate, 2
-Hydroxyethyl methacrylate (hereinafter, acrylate and methacrylate will be referred to as (meth) acrylate), 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2
-Hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth)
Acrylamide, Alonix 5700, 4-hydroxystyrene manufactured by Toa Gosei Chemical Industry Co., Ltd., HE-10, HE-20, HP-1 and HP-20 manufactured by Nippon Shokubai Chemical Industry Co., Ltd. Acrylic ester oligomer having a hydroxyl group), Blemmer PP series (polypropylene glycol methacrylate), Blemmer PE series (polyethylene glycol monomethacrylate), Blemmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Blemmer AP-400 manufactured by NOF Corporation (Polypropylene glycol monoacrylate), Blemmer A
E-350 (polyethylene glycol monoacrylate), Blemmer NKH-5050 (polypropylene glycol polytrimethylene monoacrylate) and Blemmer GLM (glycerol monomethacrylate),
Ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compounds obtained by reacting a hydroxyl group-containing vinyl compound with ε-caprolactone. Among them, 2-hydroxypropyl acrylate is preferable because it can impart excellent acid resistance and water resistance to the coating film.

Representative examples of the ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound include, for example, a compound represented by the following general formula (3):

[0037]

Embedded image

(Wherein R is a hydrogen atom or a methyl group, n
Represents an integer of 1 or more) and has a structure represented by the following formula: Placel FA-1 (R =
H, n = 1), Placel FA-4 (R = H, n
= 4), Placel FM-1 (R = CH ₃ , n =
1), Placel FM-4 (R = CH ₃ , n =
4), TONE M-100 manufactured by UCC (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.

Examples of the unit having an epoxy group include glycidyl (meth) acrylate.

In addition to the unit having a hydrolyzable silyl group, the unit having an epoxy group, and the unit having an alcoholic hydroxyl group, specific examples of a unit obtained by polymerizing a monomer copolymerizable with a monomer giving these units are given below. Examples include, for example, units from derivatives of (meth) acrylic acid. Examples of the (meth) acrylic acid derivative include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl ( (Meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile,
Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methyl Acrylamide,
AS, a macromonomer manufactured by Toa Gosei Chemical Industry Co., Ltd.
-6, AN-6, AA-6, AB-6, AK-5, hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyalkyl esters of (meth) acrylic acid and phosphoric acid or A phosphate ester group-containing vinyl compound which is a condensation product with phosphate esters,
(Meth) acrylates containing a urethane bond or a siloxane bond are exemplified.

Specific examples of the copolymerizable compound other than the (meth) acrylic acid derivative include, for example, styrene, α-
Aromatic hydrocarbon vinyl compounds such as methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene; maleic acid, fumaric acid,
Unsaturated carboxylic acids such as itaconic acid, salts thereof (alkali metal salts, ammonium salts, amine salts, etc.), their acid anhydrides (maleic anhydride, etc.) Esters of unsaturated carboxylic acids such as diesters or half esters with alcohols; vinyl esters and allyl compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl compounds containing amino groups such as vinyl pyridine and aminoethyl vinyl ether; itaconic acid Amide group-containing vinyl compounds such as diamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone;
Hydroxyethyl vinyl ether, methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene,
Other vinyl compounds such as isoprene, fluoroolefin maleimide, N-vinylimidazole, and vinyl sulfonic acid are exemplified.

Among the copolymerizable (meth) acrylic acid derivatives and the copolymerizable compounds other than the (meth) acrylic acid derivatives, polar copolymers having amine, carboxylic acid, sulfonic acid, and phosphoric acid groups are preferred. When an acidic compound is used, it is desirable to use 0 to 5% (% by weight, hereinafter the same) in the component (A) in order to suppress a crosslinking reaction at the time of polymerization.

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 a copolymer other than the (meth) acrylic acid derivative may be used. It may contain a segment derived from a sex compound.

The molecular weight of the vinyl copolymer (B) is from 1000 to 3 in view of the physical properties of the coating composition of the curable composition for paints of the present invention produced using the vinyl copolymer (B).
The range of 0000 is preferable, and the range of 2000 to 25000 is more preferable.

The units constituting the vinyl copolymer (B) include units having a hydrolyzable silyl group, and units such as a unit made of a monomer copolymerizable with a monomer to be these units. And so on.

The unit having a hydrolyzable silyl group is formed, for example, by polymerizing an alkoxysilyl group-containing vinyl copolymerizable compound. Examples of the alkoxysilyl group-containing vinyl copolymerizable compound include, for example,

[0047]

Embedded image

[0048]

Embedded image

Examples thereof include (meth) acrylates having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond. These alkoxysilyl group-containing vinyl copolymerizable compounds may be used alone or in combination of two or more as necessary.

Specific examples of a unit obtained by polymerizing a monomer copolymerizable with a monomer giving these units together with the unit having a hydrolyzable silyl group include an alcoholic hydroxyl group-containing vinyl copolymerizable unit. Units derived from a vinyl copolymerizable compound other than the compound are exemplified. Examples of (meth) acrylic acid derivatives in the vinyl copolymerizable compound include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (Meth) acrylonitrile, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth)
Acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth)
Acrylamide, N, N-dimethyl (meth) acrylamide, N-methylacrylamide, AS-6, AN-6, which are macromonomers manufactured by Toa Gosei Chemical Industry Co., Ltd.
Condensation of hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as AA-6, AB-6, AK-5 and hydroxyalkyl esters of (meth) acrylic acid with phosphoric acid or phosphoric acid esters. Examples of the product include a phosphoric ester group-containing vinyl compound and a (meth) acrylate containing a urethane bond or a siloxane bond. Specific examples of the copolymerizable compound other than the (meth) acrylic acid derivative include, for example, aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene; Unsaturated carboxylic acids, such as maleic acid, fumaric acid, itaconic acid, etc., their salts (alkali metal salts, ammonium salts, amine salts, etc.), their acid anhydrides (maleic anhydride, etc.), or their carbon number Esters of unsaturated carboxylic acids such as diesters or half esters with 1-20 linear or branched alcohols; vinyl esters and allyl compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl pyridine, aminoethyl vinyl ether and the like Amino group-containing vinyl compound; itacone Amide group-containing vinyl compounds such as diamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone; methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide, Other vinyl compounds such as N-vinylimidazole and vinylsulfonic acid are exemplified.

A vinyl copolymer containing both a hydrolyzable silyl group, an epoxy group and an alcoholic hydroxyl group (A), and a vinyl copolymer containing a hydrolyzable silyl group and containing no alcoholic hydroxyl group (B) ) Is obtained from the monomer giving the unit, for example,
No. 5, No. 57-36109, No. 58-157
Although it can be produced by the method described in JP-A-810, it is most preferably produced by a solution polymerization method using an azo radical initiator such as azobisisobutyronitrile from the viewpoint of ease of synthesis. .

At this time, if necessary, n-dodecylmercaptan, tert-dodecylmercaptan, n-butylmercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptotriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane mercaptopropyl methyl diethoxy silane, (CH ₃ O) ₃ Si-
Using a chain transfer agent such as _{S-S-Si (OCH 3} ) 3, it may be adjusted molecular weight. In particular, it is preferable to use a chain transfer agent having an alkoxysilyl group in the molecule, for example, γ-mercaptopropyltrimethoxysilane, because the alkoxysilyl group can be introduced into the terminal of the silyl group-containing acrylic copolymer.

The polymerization solvents used in the solution polymerization method include hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), alcohols (methanol, etc.). ,
Non-reactive such as ethanol, isopropanol, n-butanol, ethers (ethyl cellosolve, butyl cellosolve, cellosolve acetate, etc.), ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, acetone, etc.) It is recommended to use the solvent of

These polymerization solvents may be used alone.
Two or more of them may be used in combination. In particular, when a vinyl copolymer (A) containing both a hydrolyzable silyl group, an epoxy group and an alcoholic hydroxyl group is polymerized, the vinyl copolymer is used. Of the total copolymerizable compound constituting 10
If the amount of the alcoholic solvent such as methanol or butanol in the solvent composition is less than 1 part when the amount is 0 parts, gelation may occur during polymerization. Therefore, it is preferable that the solvent composition used in the polymerization of the vinyl copolymer (A) containing both a hydrolyzable silyl group, an epoxy group and an alcoholic hydroxyl group contains an alcoholic solvent. Is 1 when the total copolymerizable compound constituting the vinyl copolymer is 100 parts.
It is preferable to use up to 30 parts.

Examples of the curing catalyst of component (C) used in the present invention include organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, tin octylate; Phosphoric acid or phosphoric acid ester such as monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; propylene oxide, butylene oxide, cyclohexene Oxide, glycidyl methacrylate, glycidol, acrylic glycidyl ether, γ-glycidoxypropyltrimethoxysilane, γ Glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane,

[0056]

Embedded image

Cardura E manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 828 manufactured by Yuka Shell Epoxy Co., Ltd.
Addition reaction product of epoxy compound such as Epikote 1001 with phosphoric acid and / or monophosphate; organic titanate compound; organic aluminum compound; maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, succinic acid , Phthalic acid, trimellitic acid,
Pyromellitic acid and anhydrides thereof; acidic compounds such as dodecylbenzenesulfonic acid and p-toluenesulfonic acid and reactants thereof with amines; hexylamine;
Amines such as di-2-ethylhexylamine, N, N-dimethyldodecylamine, dodecylamine, DABCO, DBU, morpholine, diisopropanolamine;
Reaction products of these amines and 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, organotin compounds, acid phosphates, reactants of acid phosphates with amines, saturated or unsaturated polycarboxylic acids or acid anhydrides thereof, sulfonic acids or amines thereof , An organic titanate compound, an organoaluminum compound or a mixture thereof is preferred because of its high activity.

Examples of the hydrolyzable silicon compound of the component (D) used in the present invention include ethyl silicate,
Examples thereof include hydrolyzable ester compounds such as tetraalkoxysilanes such as methylsilicate and alkyltrialkoxysilanes such as methyltrimethoxysilane, and partial hydrolyzates thereof. Among these, a partially hydrolyzed condensate of tetraalkoxysilane is preferred in terms of curability and hardness.

The proportion of the components (A) and (B) used is
(A) 95 to 5 parts, preferably 90 to 50 parts, more preferably 85 to 65 parts, and (B) component 5 to 95
Parts, preferably 10 to 50 parts, more preferably 15 to 3 parts
5 parts. When the ratio of the component (A) and the component (B) is within the above range, the gel fraction of the obtained cured product,
The water-resistant gel fraction retention rate, acid resistance, abrasion resistance and the like are favorable, and the balance is excellent.

The component (D) is used in an amount of 70 parts or less, more preferably 50 parts or less, particularly 30 parts or less, based on 100 parts of the total amount of the components (A) and (B). Not more than 20 parts.

Component (C) is used in an amount of 0.001 to 10 based on 100 parts of the total of components (A) and (B).
Parts, preferably 0.05 to 10 parts. If the amount of the component (C) is less than 0.01 part, the curability tends to decrease, and if it exceeds 10 parts, the appearance of the coating film tends to decrease.

In order to further reduce the viscosity of the composition of the present invention, an amino resin such as organopolysiloxane silanol or melamine is preferably added to 100 parts by weight of the total of components (A) and (B). You may add in the range of 50 parts or less, More preferably, 30 parts or less.

In the composition of the present invention, the ratio of alcoholic hydroxyl group / hydrolyzable silyl group is 0.1 / 1 to 1 in number ratio.
As long as the ratio is 3.0 / 1, a hydroxyl group-containing high molecular weight compound such as an acrylic polyol, a polycarbonate diol, or a polyester diol may be added.

The composition of the present invention may contain a hydrolyzable ester compound as a dehydrating agent and an alkyl alcohol as a solvent.

Examples of the dehydrating agent include ester compounds such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate and ethyl orthoacetate, and hydrolyzable ester compounds.

These dehydrating agents may be added during the polymerization of the components (A) and (B), or may be added after the polymerization. The amount of the dehydrating agent added is 70 parts or less, preferably 50 parts or less, more preferably 20 parts or less, based on 100 parts of the total amount of the components (A) and (B).

Examples of the alkyl alcohol used as a solvent include alcohols having 1 to 10 carbon atoms in the alkyl group. Specific examples of such alcohols 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.

The amount of the alcohol used is not particularly limited, but is usually 70 parts or less, preferably 50 parts or less, more preferably 20 parts or less, per 100 parts of the total amount of the components (A) and (B). Parts or less, when using a solvent alone without using a dehydrating agent, usually 0.5 to 70 parts,
Preferably it is 1 to 50 parts, more preferably 2 to 20 parts.

When the alcohol or the alcohol and the dehydrating agent are used in combination, the storage stability is higher than when the composition comprising the components (A), (B), (C) and (D) is stored. Is significantly improved. The amount of the solvent exhibiting such effects varies depending on the molecular weight and composition of the component (A), the component (B), the component (C) and the component (D) in the composition of the present invention. Although it is not possible, the composition may be adjusted so that the solid content concentration, viscosity, and the like required for practical use are obtained.

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 or a light stabilizer, especially by using them together.

As the UV absorber, conventionally known UV absorbers can be widely used, and for example, UV absorbers such as benzophenone type, triazole type, phenyl salicylate type, diphenyl acrylate type and acetophenone type are preferable.

As the light stabilizer, conventionally known light stabilizers can be widely used, for example, bis (2,2,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,2)
6,6-pentamethyl-4-piperidyl) sebacate,
Bis (1,2,2-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate
2,6,6-pentamethyl-4-piperidyl), tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2 2,6,6-pentamethyl-
4-piperidyl) -1,2,3,4-butanetetracarboxylate and the like. These may be used alone or in combination of two or more.

The compounding amount 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 coating, additives such as a diluent, an anti-cissing agent and a leveling agent may be used depending on the application; cellulose based materials such as nitrocellulose and cellulose acetate butyrate Compounds: epoxy resin, melamine resin, vinyl chloride resin,
Resins such as chlorinated polypropylene, chlorinated 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 of 50 to 70%, and is applied to a substrate by a method such as spray coating, brush coating, roll coating, and dip coating. Thereafter, the composition is cured by heating at about 80 to 160 ° C. to form a cured coating film having excellent chemical resistance such as acid resistance, weather resistance, and scratch resistance.

The composition of the present invention is useful for coating automobiles, architectural exteriors, industrial machines, steel furniture, plastics, etc., and is particularly useful as a top coating for automobiles.

Next, the curable composition for paints of the present invention was
A more specific description will be given based on examples.

Synthesis Example 1 (Synthesis of Vinyl Copolymer Containing Hydrolyzable Silyl Group and Alcoholic Hydroxyl Group (A-1)) A stirrer, a thermometer, a reflux condenser, a nitrogen gas inlet tube and a dropping funnel were provided. 26.0 parts of Solvesso 100 (a petroleum-based aromatic solvent manufactured by Exxon Chemical Co., Ltd.) were charged into the reaction vessel, and the temperature was raised to 110 ° C. while introducing nitrogen gas. The solution was dropped at a constant speed from the dropping funnel over 3 hours.

Styrene 15.0 parts Methyl methacrylate 8.3 parts n-butyl acrylate 34.3 parts 2-hydroxypropyl acrylate 22.4 parts γ-methacryloxypropyl trimethoxysilane 20.0 parts 2,2′-azobis ( 2-methylbutyronitrile) (V-59 (manufactured by Wako Pure Chemical Industries, Ltd.)) 6.46 parts Methyl orthoacetate 2.0 parts Solvesso 100 3.5 parts Methanol 2.0 parts After dropping of the mixture, 0.34 part of V-59, 5.0 parts of Solvesso 100, 2.0 parts of methyl orthoacetate, and 10.0 parts of xylene were dropped at a constant speed over 30 minutes, and then 1 hour and 30 hours.
After the polymerization, the mixture was cooled and methyl orthoacetate was added.
0 parts, methanol 4.0 parts, and further, Solvesso 100 was added to the resin solution to adjust the solid content to 60%, and the hydrolyzable silyl group and alcoholic hydroxyl group-containing vinyl copolymer (A- The solution of 1) was obtained. The number average molecular weight of the obtained vinyl copolymer (A-1) is 4000.
Met. The hydroxyl equivalent and the silyl equivalent of the obtained vinyl copolymer (A-1) were 580 and 1240, respectively.

Synthesis Example 2 (Synthesis of vinyl copolymer containing hydrolyzable silyl group and alcoholic hydroxyl group (A-2)) Synthetic Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. A solution of a hydrolyzable silyl group- and alcoholic hydroxyl group-containing vinyl copolymer (A-2) having a solid content of 60% was obtained in the same manner as described above.

Styrene 15.0 parts Methyl methacrylate 0.1 parts n-butyl acrylate 42.5 parts 2-hydroxyethyl methacrylate 22.4 parts γ-methacryloxypropyltrimethoxysilane 20.0 parts Vinyl copolymer obtained The number average molecular weight of the compound (A-2) was 3,900.

The obtained vinyl copolymer (A-2)
The hydroxyl equivalent and the silyl group equivalent were 580 and 1240, respectively.

Synthesis Example 3 (Synthesis of vinyl copolymer (A-3) containing hydrolyzable silyl group and alcoholic hydroxyl group) Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. In the same manner as in the above, a solution of a vinyl copolymer (A-3) having a solid content of 60% and containing a hydrolyzable silyl group and an alcoholic hydroxyl group was obtained.

Styrene 15.0 parts Methyl methacrylate 10.6 parts n-butyl acrylate 34.4 parts 2-hydroxyethyl acrylate 20.0 parts γ-methacryloxypropyltrimethoxysilane 20.0 parts The number average molecular weight of the combined product (A-3) was 3,900.

The obtained vinyl copolymer (A-3)
The hydroxyl equivalent and the silyl group equivalent were 580 and 1240, respectively.

Synthesis Example 4 (Synthesis of vinyl copolymer (A-4) containing hydrolyzable silyl group and alcoholic hydroxyl group) Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. In the same manner as in the above, a solution of a vinyl copolymer (A-4) containing a hydrolyzable silyl group and an alcoholic hydroxyl group having a solid content of 60% was obtained.

Styrene 15.0 parts Methyl methacrylate 7.9 parts n-butyl acrylate 18.0 parts Placel FA-1 39.1 parts (manufactured by Daicel Chemical Industries, Ltd.) γ-methacryloxypropyltrimethoxysilane 20.0 The number average molecular weight of the obtained vinyl copolymer (A-4) was 4,300.

The obtained vinyl copolymer (A-4)
The hydroxyl equivalent and the silyl group equivalent were 624 and 1240, respectively.

Synthesis Example 5 (Synthesis of vinyl copolymer containing hydrolyzable silyl group and alcoholic hydroxyl group (A-5)) Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. In the same manner as in the above, a solution of a vinyl copolymer (A-5) containing a hydrolyzable silyl group and an alcoholic hydroxyl group having a solid content of 60% was obtained.

Styrene 15.0 parts Methyl methacrylate 0.4 parts n-butyl acrylate 22.5 parts Placel FM-1 42.1 parts (manufactured by Daicel Chemical Industries, Ltd.) γ-methacryloxypropyltrimethoxysilane 20.0 The number average molecular weight of the obtained vinyl copolymer (A-5) was 4,300. The hydroxyl equivalent and the silyl group equivalent of the obtained vinyl copolymer (A-5) were 580 and 1240, respectively. there were.

Synthesis Example 6 (Synthesis of vinyl copolymer containing hydrolyzable silyl group and alcoholic hydroxyl group (A-6)) A stirrer, a thermometer, a reflux condenser, a nitrogen gas inlet tube and a dropping funnel were provided. 13.0 parts of Solvesso 100 (a petroleum aromatic solvent manufactured by Exxon Chemical Co., Ltd.)
After charging 13.0 parts of n-butyl alcohol and raising the temperature to 110 ° C. while introducing nitrogen gas, a mixture having the following composition was dropped at a constant speed from the dropping funnel over 3 hours.

Styrene 15.0 parts Methyl methacrylate 8.3 parts n-butyl acrylate 34.3 parts 2-hydroxypropyl acrylate 22.4 parts γ-methacryloxypropyltrimethoxysilane 20.0 parts V-59 (Wako Pure Chemical Industries, Ltd.) 6.46 parts Methyl orthoacetate 2.0 parts Solvesso 100 3.5 parts Methanol 2.0 parts 0.34 parts of V-59 and 5.0 parts of Solvesso 100 after dropping of the mixture. 2.0 parts of methyl orthoacetate, n-
Butyl alcohol (10.0 parts) was added dropwise at a constant speed over 30 minutes, polymerization was carried out for 1 hour and 30 minutes, the mixture was cooled, 4.0 parts of methyl orthoacetate and 4.0 parts of methanol were added. Add 100 and solid content is 60%
And a solution of a hydrolyzable silyl group and an alcoholic hydroxyl group-containing vinyl copolymer (A-6) was obtained.

The obtained vinyl copolymer (A-6) had a number average molecular weight of 4,000.

The obtained vinyl copolymer (A-6)
The hydroxyl equivalent and the silyl group equivalent were 580 and 1240, respectively.

Synthesis Example 7 (Synthesis of vinyl copolymer containing hydrolyzable silyl group and alcoholic hydroxyl group (A-7)) Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. In the same manner as in the above, a solution of a hydrolyzable silyl group- and alcoholic hydroxyl group-containing vinyl copolymer (A-7) having a solid content of 60% was obtained.

Styrene 15.0 parts Methyl methacrylate 4.7 parts n-butyl acrylate 20.3 parts 2-hydroxypropyl acrylate 20.0 parts γ-methacryloxypropyl trimethoxysilane 40.0 parts The number average molecular weight of the compound (A-7) was 4,200.

The obtained vinyl copolymer (A-7)
The hydroxyl equivalent and the silyl group equivalent were 650 and 620, respectively.

Synthesis Example 8 (Synthesis of vinyl copolymer containing hydrolyzable silyl group and alcoholic hydroxyl group (A-8)) Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. A solution of a hydrolyzable silyl group- and alcoholic hydroxyl group-containing vinyl copolymer (A-8) having a solid content of 60% was obtained in the same manner as in the above.

Styrene 15.0 parts Methyl methacrylate 7.8 parts n-butyl acrylate 17.2 parts 2-hydroxypropyl acrylate 30.0 parts γ-methacryloxypropyltrimethoxysilane 30.0 parts The obtained vinyl copolymer The number average molecular weight of the combined product (A-8) was 4,300.

The obtained vinyl copolymer (A-8)
Of the compound had a hydroxyl equivalent and a silyl group equivalent of 433 and 827, respectively.

Synthesis Example 9 (Synthesis of vinyl copolymer containing hydrolyzable silyl group and alcoholic hydroxyl group (A-9)) Synthetic Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. A solution of a hydrolyzable silyl group- and alcoholic hydroxyl group-containing vinyl copolymer (A-9) having a solid content of 60% was obtained in the same manner as in the above.

Styrene 15.0 parts Methyl methacrylate 20.5 parts n-butyl acrylate 31.5 parts 2-hydroxypropyl acrylate 13.0 parts γ-methacryloxypropyl trimethoxysilane 20.0 parts Vinyl copolymer obtained The number average molecular weight of the combined product (A-9) was 4,100.

The obtained vinyl copolymer (A-9)
The hydroxyl group equivalent and the silyl group equivalent were 1000 and 1240, respectively.

Synthesis Example 10 (Synthesis of Hydrolyzable Silyl Group-Containing Vinyl Copolymer (B-1)) A reaction vessel equipped with a stirrer, thermometer, reflux cooler, nitrogen gas inlet tube and dropping funnel was prepared. And Solvesso 100 (exxon chemical Co., Ltd., petroleum-based aromatic solvent) were charged, and the temperature was raised to 110 ° C. while introducing nitrogen gas. It was dropped at a constant speed over time.

Styrene 13.2 parts Methyl methacrylate 4.8 parts Isobutyl acrylate 29.5 parts γ-methacryloxypropyltrimethoxysilane 52.0 parts Acrylamide 0.5 parts V-59 (manufactured by Wako Pure Chemical Industries, Ltd.) 4.56 parts Methyl orthoacetate 2.0 parts Solvesso 100 8.0 parts n-butyl alcohol 2.0 parts Xylene 9.3 parts 0.24 parts of V-59 and 5. 4 parts, 6.0 parts of xylene and 2.0 parts of n-butyl alcohol were dropped at a constant speed over 30 minutes, and 1 hour 3
After polymerization for 0 minutes, the mixture was cooled, 4.0 parts of methyl orthoacetate and 2.0 parts of methanol were added, and Solvesso 100 was added to the resin solution to prepare a solid content of 60%, followed by hydrolysis. A solution of a vinyl copolymer (B-1) containing a hydrophilic silyl group and an alcoholic hydroxyl group was obtained. The number average molecular weight of the obtained vinyl copolymer (B-1) is 40.
00. The obtained vinyl copolymer (B-
The silyl group equivalent of 1) was 477.

Synthesis Example 11 (Synthesis of vinyl copolymer (A-10) containing epoxy group, hydrolyzable silyl group and alcoholic hydroxyl group) Stirrer, thermometer, reflux condenser, nitrogen gas inlet tube 26.0 parts of Solvesso 100 (exxon chemical Co., Ltd., petroleum-based aromatic solvent) were charged into a reaction vessel equipped with a dropping funnel, and heated to 110 ° C. while introducing nitrogen gas. A mixture having the indicated composition was dropped at a constant rate over 3 hours using a dropping funnel.

Mixture (c) Styrene 15 parts Methyl methacrylate 4 parts n-butyl acrylate 23.6 parts 2-hydroxyethyl acrylate 22.4 parts γ-methacryloxypropyltrimethoxysilane 20 parts Glycidyl methacrylate 15 parts 2,2′- Azobis (2-methylbutyronitrile (V-59 (manufactured by Wako Pure Chemical Industries, Ltd.)) 6.46 parts Methyl orthoacetate 2 parts Solvesso 100 3.5 parts Methanol 2 parts After dropping of the mixture, V-59 0.3 parts, 5.0 parts of Solvesso 100, 2.0 parts of methyl orthoacetate, and 10.0 parts of xylene were dropped at a constant speed over 30 minutes, and polymerization was performed for 1 hour and 30 minutes, followed by cooling. Methyl orthoacetate 4.0
And 4.0 parts of methanol, and Solvesso 100 was further added to the resin solution to adjust the solid content to 60%. A vinyl copolymer containing an epoxy group, a hydrolyzable silyl group and an alcoholic hydroxyl group was added. A solution of the combination (A-10) was obtained. The number average molecular weight of the obtained vinyl copolymer (A-10) was 4,100. Further, the hydroxyl equivalent and the silyl equivalent of the obtained vinyl copolymer (A-10) were 580 and 1240, respectively.

Comparative Synthesis Example 1 (Synthesis of Hydrolyzable Silyl Group-Containing Vinyl Copolymer (C-1)) The procedure of Synthesis Example 1 was repeated except that a mixture having the following composition was used as the copolymerizable compound mixture. Thus, a solution of a hydrolyzable silyl group-containing vinyl copolymer (C-1) having a solid content of 60% was obtained.

Styrene 18.0 parts n-butyl acrylate 35.0 parts γ-methacryloxypropyltrimethoxysilane 47.0 parts The number average molecular weight of the obtained vinyl copolymer (C-1) was 4,300. .

The obtained vinyl copolymer (C-1)
Had a silyl group equivalent of 528.

Comparative Synthesis Example 2 (Synthesis of Organic Polyol Copolymer (D-1)) The solid content was changed in the same manner as in Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. A solution of a 60% hydrolyzable silyl group-containing vinyl copolymer (D-1) was obtained.

Styrene 15.0 parts Methyl methacrylate 20.3 parts n-butyl acrylate 31.4 parts 2-hydroxyethyl acrylate 33.3 parts The obtained vinyl copolymer (D-1) has a number average molecular weight of 4000. Met.

The obtained vinyl copolymer (D-1)
Had a hydroxyl equivalent of 348.

Comparative Synthesis Example 3 (Synthesis of Organic Polyol Copolymer (D-2)) The solid content was changed in the same manner as in Synthesis Example 1 except that a mixture having the following composition was used as the copolymerizable compound mixture. A solution of a 60% hydrolyzable silyl group-containing vinyl copolymer (D-2) was obtained.

Styrene 15.0 parts Methyl methacrylate 2.8 parts n-butyl acrylate 44.9 parts 2-hydroxyethyl acrylate 37.3 parts The obtained vinyl copolymer (D-2) has a number average molecular weight of 3,800. Met.

The obtained vinyl copolymer (D-2)
Has a hydroxyl equivalent of 349.

Comparative Synthesis Example 4 (Synthesis of Hydrolyzable Silyl Group and Alcohol-Hydroxy Group-Containing Vinyl Copolymer (E-1)) Synthetic example except that a mixture having the following composition was used as the copolymerizable compound mixture. In the same manner as in Example 1, a solution of a hydrolyzable silyl group- and alcoholic hydroxyl group-containing vinyl copolymer (E-1) having a solid content of 60% was obtained.

Methyl methacrylate 10.0 parts 2-hydroxyethyl acrylate 80.0 parts γ-methacryloxypropyltrimethoxysilane 10.0 parts The obtained vinyl copolymer (E-1) has a number average molecular weight of 4,500. there were.

The obtained vinyl copolymer (E-1)
Had a hydroxyl equivalent and a silyl group equivalent of 163 and 2480, respectively.

Comparative Synthesis Example 5 (Synthesis of Vinyl Copolymer Containing Hydrolyzable Silyl Group and Alcoholic Hydroxyl Group (E-2)) Synthetic example except that a mixture having the following composition was used as the copolymerizable compound mixture. In the same manner as in 1, a solution of a hydrolyzable silyl group- and alcoholic hydroxyl group-containing vinyl copolymer (E-2) having a solid content of 60% was obtained.

Styrene 15.0 parts Methyl methacrylate 27.8 parts n-butyl acrylate 32.2 parts 2-hydroxypropyl acrylate 5.0 parts γ-methacryloxypropyl trimethoxysilane 20.0 parts The vinyl copolymer obtained The number average molecular weight of the combined product (E-2) was 4000.

The obtained vinyl copolymer (E-2)
Had a hydroxyl equivalent and a silyl group equivalent of 2600 and 1240, respectively.

Table 1 shows the components in the above synthesis examples and comparative synthesis examples and the physical properties of the respective synthesized products.

[0125]

[Table 1]

Reference Examples 1 to 9 and Comparative Examples 1 to 5 The copolymers obtained in Synthesis Examples 1 to 10 and the copolymers obtained in Comparative Synthesis Examples 1 to 5 were blended so as to have the composition shown in Table 2. . In Reference Examples 1 to 9 and Comparative Examples 1 to 4, 0.4% of a leveling agent (Dispalon L-1984-50 manufactured by Kusumoto Kasei Co., Ltd.) with respect to the total solid content, (C)
As a curing catalyst of the component, 2% of a mixture of dodecylbenzenesulfonic acid / diisopropanolamine = 1 / 1.03 (equivalent ratio) was added. This mixture was diluted with Solvesso 100 to adjust the viscosity of the Ford cup to 15 to 20 seconds, and a top coat clear was used as a paint.

A coated plate obtained by coating a degreased and phosphoric acid-treated mild steel plate with an epoxyamide-based cationic electrodeposition primer for automobiles and an intermediate coating surfacer as a test piece, and a high solid type acrylic melamine resin paint (Black metallic base) as a base coat. Next, the clear coating material for a top coat was applied on a wet-on-wet basis, set for 20 minutes, and 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. The obtained coating film was evaluated by the following method. Table 2 shows the results.

(Gel Fraction) A free clear film baked at 140 ° C. for 30 minutes was weighed accurately.
It was wrapped in a 0-mesh stainless steel wire mesh (W ₀ ) and weighed precisely (W ₁ ). This was immersed and extracted in acetone for 24 hours, dried, weighed accurately (W ₂ ), and the gel fraction was determined according to the following equation.

Gel fraction (%) = 100 × (W ₂ −W ₀ ) / (W ₁ −W ₀ ) (water-resistant gel fraction retention) The free clear film baked at 140 ° C. for 30 minutes has already been prepared. Finely weighed 300
'It was precisely weighed wrapped in ₍₀ (W mesh of stainless steel wire mesh W)' _1). This was immersed in water at 80 ° C. for 24 hours, taken out, further immersed in acetone for 24 hours and extracted, dried, weighed (W ′ ₂ ), and the water-resistant gel fraction was calculated according to the following equation. Was.

Water resistant gel fraction (%) = 100 × (W ′ ₂ −
W ′ ₀ ) / (W ′ ₁ −W ′ ₀ ) For the same sample, the gel fraction value measured in advance was used to determine the water-resistant gel fraction retention according to the following equation.

Water-resistant gel fraction retention rate (%) = 100 × (water-resistant gel fraction) / (gel fraction) (acid resistance) Four drops of 10% sulfuric acid aqueous solution were dropped on a test panel using a pipette. After heating at 70 ° C. for 30 minutes in a drier, the aqueous sulfuric acid solution was washed off with water, and the state of change on the surface of the coating film was observed and evaluated according to the following criteria.

10 points No change from before spot 9 points Slight change observed 8 points Circular trace remains 7 points Discoloration or swelling is slightly recognized 6 points Gloss reduction or discoloration is slightly recognized 5 points Glossy Deterioration and discoloration are clearly observed 4 points Slight shrinkage and obvious swelling are observed 3 points Slight lifting, severe shrinkage and discoloration are observed 2 points Lifting is clearly observed 1 point Film dissolution is observed (Abrasion resistance) A test piece was fixed horizontally, and an abrasive (JIS 8 type loam 1.2%, JIS 11 type loam 1.2%, kaolin 0.6%, neutral detergent 1.0%) was placed on the test piece. , Water (96.0% mixture), and a weight (contact surface diameter 5 cm, load 22 g / cm ² ) covered with kraft paper was stroked on the coating surface. 20 ° gloss after 0 and 20 strokes was measured with a gloss meter, and the gloss retention (G
The scuff resistance was evaluated in R). The larger the GR, the better the scratch resistance.

[0134]

[Table 2]

From the results shown in Table 2, the hydrolyzable silicon compound was added to a blend of a vinyl copolymer containing a hydrolyzable silyl group, an epoxy group and an alcoholic hydroxyl group and a vinyl polymer containing a hydrolyzable silyl group. It can be seen that the use of the added product is superior in water resistance, acid resistance and scratch resistance as compared with a blend system of a hydrolyzable silyl group-containing vinyl copolymer and acrylic polyol.

Examples 1 to 3 and Reference Example 10 The compositions shown in Table 3 were prepared and evaluated in the same manner as in Reference Example 1. Table 3 shows the results.

[0137]

[Table 3]

[0138]

The curable composition for coatings of the present invention comprises a vinyl copolymer having a specific hydrolyzable silyl group, an epoxy group and an alcoholic hydroxyl group, and a specific alcoholic hydroxyl group equivalent. Since a vinyl copolymer having a hydrolyzable silyl group is used as a base resin, and a hydrolyzable silicon compound is added thereto and used, acid resistance, water resistance, scratch resistance and weather resistance are good, and They have an excellent balance, and can be suitably used for, for example, topcoats used in automobiles, industrial machines, steel furniture, building exteriors, home appliances, plastics and the like.

Claims (4)

[Claims] (A) The main chain is substantially composed of a vinyl copolymer chain, and the terminal of the main chain and / or the side chain has the general formula (1): (Wherein, R ¹ is an alkyl group having 1 to 10 carbon atoms, R ² is 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; a represents 0, 1 or 2) in the molecule, each having at least one hydrolyzable silyl group and an epoxy group, and having an alcoholic hydroxyl group at the terminal of the main chain and / or the side chain. 95 to 5 parts by weight of a vinyl copolymer having an alcoholic hydroxyl group equivalent of 180 to 2000 (g / mol) therein, (B) the main chain substantially consisting of a vinyl copolymer chain, General formula (2) at the terminal and / or side chain: (Wherein, R ³ is an alkyl group having 1 to 10 carbon atoms, R ⁴ is 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; b represents 0, 1 or 2) 5 to 95% by weight of a vinyl copolymer having at least one hydrolyzable silyl group in the molecule and having no alcoholic hydroxyl group in the same molecule Parts, (C) a curing catalyst and (D) a hydrolyzable silicon compound, wherein component (C) is added in an amount of 0.00
A curable composition for paints containing 1 to 10 parts by weight. 2. A vinyl copolymer as component (A) having a hydrolyzable silyl group equivalent of 380 to 30,000 (g / mo).
The curable composition according to claim 1, which is l). 3. The composition according to claim 1, wherein the ratio of alcoholic hydroxyl group / hydrolyzable silyl group in the vinyl copolymer as component (A) is from 0.1 / 1 to 3.0 / 1 in number ratio. Curable composition. 4. The vinyl copolymer as the component (A),
The curable composition according to claim 1, wherein the curable composition is a vinyl copolymer using 2-hydroxypropyl (meth) acrylate, which is an alcoholic hydroxyl group-containing vinyl copolymerizable compound, as a copolymerization component.