JP3412916B2 - Curable composition for paint - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a curable composition for paints. More specifically, for example, it can be suitably used for top coatings used for automobiles, industrial machines, steel furniture, interior and exterior of buildings, home appliances, plastics, etc., and has particularly excellent acid resistance, water resistance and weather resistance. The present invention relates to a curable composition for paints that exhibits thermosetting properties, recoat adhesion properties, and the like and can be suitably used as a topcoat paint for automobiles.

[0002]

2. Description of the Related Art Conventionally, paints containing melamine resins such as alkyd melamine and acrylic melamine have been mainly used for painting automobiles, interior and exterior of buildings, industrial machines, steel furniture, plastics, etc. The melamine resin has a problem that harmful formalin is generated at the time of curing and the cured coating film is inferior in acid resistance, so that it is attacked by acid rain.

In particular, the problem of acid rain caused by air pollution in recent years has become serious, and there are phenomena such as etching, whitening, and stains on the coating film.

In order to solve the above-mentioned problems, the present inventors have found that a vinyl-based copolymer having a hydrolyzable silyl group or a blend of a vinyl-based copolymer having a hydrolyzable silyl group and an acrylic polyol. System, as a result of studying the use of a copolymer such as a vinyl-based monomer having a hydrolyzable silyl group and a vinyl-based monomer having an alcoholic hydroxyl group in a coating material, when these are used, It has been found that a curable resin for coatings having excellent acid resistance and weather resistance can be obtained, and a patent application has been previously filed (Japanese Patent Laid-Open No. 63-132977, etc.).

A vinyl copolymer having a hydrolyzable silyl group, a blend system of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol, and a vinyl monomer having a hydrolyzable silyl group. The characteristic of the copolymer of a vinyl monomer having an alcoholic hydroxyl group is that a hydrolyzable silyl group and an alcoholic hydroxyl group form a stable siloxane bond or siloxy bond to cure, and therefore, acrylic melamine or alkyd This means that it is possible to form a coating film having better acid resistance and weather resistance than when a melamine resin such as melamine is used, and the hydrolyzable silyl group has the general formula (II):

[0006]

[Chemical 3]

(Wherein R ⁵ is an alkyl group having 1 to 10 carbon atoms, R ⁶ 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. Hydrogen group and b represents 0, 1 or 2), the silyl group is Si-
Since it is introduced into the copolymer main chain through the C bond, it is possible to form a coating film having excellent acid resistance and weather resistance.

A blend system of the vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol is certainly excellent in thermosetting and appearance and is a relatively expensive raw material, a hydrolyzable silyl group. Since it is possible to reduce the amount of the compound having a group, there is an advantage that the cost of the curable composition can be reduced.
The blend system is not excellent in water resistance and acid resistance, and in order to further improve the compatibility between the vinyl copolymer having a hydrolyzable silyl group and the acrylic polyol, the molecular weight and copolymer The problem remains that the composition and blending ratio of the polymerizable compound are limited to some extent.

[0009] Therefore, in order to solve the above-mentioned problems, the present inventors use a vinyl-based copolymer having a hydrolyzable silyl group and an alcoholic hydroxyl group in the same molecule to achieve a marked improvement in acid resistance. Is proposing that.

However, although the vinyl-based copolymer having the hydrolyzable silyl group and the alcoholic hydroxyl group in the same molecule certainly exhibits excellent water resistance and acid resistance, for example, it is not suitable for automobile top coatings. The indispensable adhesion between coating films (hereinafter, referred to as recoat adhesion) when repainting is indispensable.

[0011]

In view of the above-mentioned conventional techniques, therefore, the present inventors have found that a coating material that exhibits excellent acid resistance, water resistance, weather resistance, and thermosetting property, as well as excellent recoat adhesion. As a result of earnestly researching the composition for use as much as possible, the present invention has found such a curable composition for coating material and completed the present invention.

[0012]

That is, the present invention provides a compound represented by the general formula (I):

[0013]

[Chemical 4]

(Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 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. The hydrogen group and R ³ have the general formula:

[0015]

[Chemical 5]

(In the formula, R4 represents a hydrogen atom or a methyl group.
Group represented by) or -CH₂-, A is 0, 1
Or 2 represents a hydrolyzable silyl group represented by
Vinyl monomer (A) 5-40% by weight, alcohol
5 to 50% by weight of a vinylic monomer (B) containing a polymerizable hydroxyl group
And tertiary amino group-containing vinyl monomer (C) 0.5 to 10
It is made by polymerizing the copolymerization component containing wt%., Alcoh
Molar ratio of hydroxyl group and hydrolyzable silyl group (alcohol
The value of the hydroxyl group / hydrolyzable silyl group) is 0.5 to 2
is thereBlended with vinyl copolymer and curing catalyst
A curable composition for paints (claim 1), Third grade
The vinyl monomer (C) containing a mino group is N, N-dialkyl
Aminoalkyl (meth) acrylate1 notes
Curable composition for paints (claimTwo), Vinyl copolymer
-Based vinyl monomer containing hydrolyzable silyl groups
(A) 20 to 31.1% by weight, containing alcoholic hydroxyl group
Vinyl monomer (B) 11.8 to 25.9% by weight, tertiary
1 to 4% by weight of an amine group-containing vinyl monomer (C) and
Other monomers (D) 41 to 6 copolymerizable with these
Vinyl produced by polymerizing 5.7% by weight of a copolymerization component
A system copolymer1OrTwoCuring property for coating materials
Composition (ClaimsThree), And tertiary in vinyl-based copolymers
The amino group equivalent is 1500 to 40,000 g / mol,
The number average molecular weight is 1,000 to 30,000,
2 orOrThreeCurable composition for paint according to claim (claimFour)
To do.

[0017]

FUNCTION AND EXAMPLE The curable composition for coating material of the present invention is
As described above, the general formula (I):

[0018]

[Chemical 6]

(In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms, 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. The hydrogen group and R ³ have the general formula:

[0020]

[Chemical 7]

(In the formula, R ⁴ represents a hydrogen atom or a methyl group) or vinyl containing a hydrolyzable silyl group represented by —CH ₂ — and a represents 0, 1 or 2. -Based monomers (hereinafter referred to as hydrolyzable silyl group-containing vinyl-based monomers) (A) 5 to 40% by weight, alcoholic hydroxyl group-containing vinyl-based monomers (B) 5 to 50% by weight, and tertiary amino Group-containing vinyl-based monomer (C) 0.5 to 1
It is characterized in that a vinyl-based copolymer obtained by polymerizing a copolymerization component containing 0% by weight and a curing catalyst are blended.

In the present invention, the hydrolyzable silyl group-containing vinyl monomer (A) represented by the general formula (I) is used as a copolymerization component for obtaining a vinyl copolymer. The monomer (A) has a silicon atom bonded to a hydrolyzable group via a Si—C bond, so that the resulting curable composition exhibits excellent acid resistance and weather resistance. Further, an alcoholic hydroxyl group-containing vinyl monomer (B) is used as a copolymerization component, and the reaction between the alcoholic hydroxyl group in the vinyl monomer (B) and the hydrolyzable silyl group The resulting curable composition exhibits excellent thermosetting properties. Furthermore, a tertiary amino group-containing vinyl monomer (C) is used as a copolymerization component, and a curable composition obtained by the tertiary amino group in the vinyl monomer (C) is excellent. It comes to exhibit recoat adhesion.

The vinyl copolymer used in the present invention is
As described above, since it has a hydrolyzable silyl group, an alcoholic hydroxyl group and a tertiary amino group in the same molecule, when the vinyl copolymer is used, it has excellent acid resistance and water resistance. It is possible to obtain a curable composition exhibiting excellent weather resistance and thermosetting property as well as excellent recoat adhesion.

In the general formula (I) of the hydrolyzable silyl group-containing vinyl monomer (A) represented by the general formula (I) (hereinafter referred to as the monomer (A)), the alkyl group represented by R ¹ is When the number of carbon atoms is too large, the reactivity of the hydrolyzable silyl group is lowered, and thus R ¹ is an alkyl group having 1 to 10 carbon atoms, preferably a methyl group, an ethyl group, An alkyl group having 1 to 4 carbon atoms such as a propyl group and a butyl group.

In the general formula (I), R ² is
An alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms exemplified in R ¹ above, for example, a phenyl group, preferably an aryl group having 6 to 25 carbon atoms, and preferably an benzyl group. Is 1 selected from the group consisting of aralkyl groups having 7 to 12 carbon atoms
It is a valent hydrocarbon group, and among these, an alkyl group having 1 to 4 carbon atoms is preferable from the viewpoint that the resulting composition has excellent curability.

Examples of the monomer (A) include

[0027]

[Chemical 8]

General formula (III) such as:

[0029]

[Chemical 9]

A compound represented by the formula: wherein R ¹ , R ² , R ⁴ and a are the same as defined above;

[0031]

[Chemical 10]

General formula (IV) such as:

[0033]

[Chemical 11]

A compound represented by the formula: wherein R ¹ , R ² and a are the same as defined above, R ⁷ is a hydrogen atom or a methyl group, and n is an integer of 1 to 12;

[0035]

[Chemical 12]

General formula (V) such as:

[0037]

[Chemical 13]

A compound represented by the formula (wherein R ¹ , R ² , R ⁷ , a and n are the same as defined above);

[0039]

[Chemical 14]

General formula (VI) such as:

[0041]

[Chemical 15]

A compound represented by the formula: wherein R ¹ , R ² , R ⁷ and a are the same as defined above, and m is an integer of 1 to 8;

[0043]

[Chemical 16]

(Wherein, p represents an integer of 0 to 20) and other general formula (VII):

[0045]

[Chemical 17]

(Wherein R ¹ , R ² , R ⁷ and a are the same as above, q is an integer of 0 to 20) and the hydrolyzable silyl group represented by the general formula (I). Examples thereof include (meth) acrylates having a group at the terminal via a urethane bond or a siloxane bond, and these can be used alone or in combination of two or more, but among these, handling is easy and low. The compound represented by the general formula (IV) is preferable from the viewpoints of cost and generation of no reaction by-product.

If the amount of the above-mentioned monomer (A) is too small, the acid resistance of the coating film formed using the obtained curable composition will be insufficient.
It is 5% by weight or more based on the total amount of the copolymerization component, and if it is too large, the storage stability of the curable composition will be somewhat inferior, so it is 40% by weight or less based on the total amount of the copolymerization component. In order to obtain a curable composition exhibiting further excellent thermosetting property, acid resistance, weather resistance and the like, the amount of the monomer (A) blended is 10% by weight or more based on the total amount of the copolymerization component,
Further, it is preferably 35% by weight or less.

Examples of the alcoholic hydroxyl group-containing vinyl monomer (B) (hereinafter referred to as the monomer (B)) include 2-hydroxyethyl (meth) acrylate and 1
-Hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, Aronix 5700 (manufactured by Toa Synthetic Chemical Industry Co., Ltd.), 4-hydroxystyrene, HE -10, H
Acrylic ester oligomers having a hydroxyl group at the terminal such as E-20, HP-1, HP-20 (above, manufactured by Nippon Shokubai Chemical Co., Ltd.), Bremmer PP series (polypropylene glycol methacrylate), Bremmer PE
Series (polyethylene glycol monomethacrylate), Bremmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Bremmer AP-400 (polypropylene glycol monoacrylate), Bremmer AE-350 (polyethylene glycol monoacrylate), Bremmer NKH-5
Compounds such as 050 (polypropylene glycol polytrimethylene monoacrylate) and Bremmer GLM (glycerol monomethacrylate) (above, NOF Corporation), ε-caprolactone obtained by the reaction of a hydroxyl group-containing vinyl compound and ε-caprolactone Examples thereof include modified hydroxyalkyl vinyl-based copolymerizable compounds.

Typical examples of the ε-caprolactone-modified hydroxyalkyl vinyl copolymerizable compound include, for example, the general formula (VIII):

[0050]

[Chemical 18]

(In the formula, R ⁸ is a hydrogen atom or a methyl group,
r is an integer of 1 or more), for example, Pl
accel FA-1 (R ⁸ is a hydrogen atom, n is 1), Placcel FA-4 (R ⁸ is a hydrogen atom, n
Represents 4), Placcel FM-1 (R ⁸ represents a methyl group, n represents 1), Placcel FM-4 (R ⁸
Is a methyl group, n is 4) (above, manufactured by Daicel Chemical Industries, Ltd.), TONEM-100 (R ⁸ is a hydrogen atom, n
Represents 2), TONE M-201 (R ⁸ represents a methyl group, and n represents 1) (above, manufactured by UCC).

The above-mentioned monomer (B) can be used alone or in combination of two or more kinds. Among these, the acid resistance and water resistance of the coating film formed by using the curable composition obtained can be used. From the viewpoint of excellent properties, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound are preferable.

If the amount of the above-mentioned monomer (B) is too small, the resulting composition will not exhibit sufficient curability, so that it is at least 5% by weight of the total amount of the copolymerization components. If the amount is too large, the coating film formed by using the curable composition will be inferior in water resistance and acid resistance and will be insufficient, so 50% by weight or less of the total amount of the copolymerization components. Is. In addition, in order to obtain a curable composition exhibiting further excellent thermosetting property and flexibility,
It is further desirable that the blending amount of the monomer (B) is 6% by weight or more, preferably 7% by weight or more, and 40% by weight or less, preferably 35% by weight or less based on the total amount of the copolymerization component.

The tertiary amino group-containing vinyl monomer (C) (hereinafter referred to as the monomer (C)) is, for example, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth). ) N, N-dialkylaminoalkyl (meth) acrylates such as acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, etc., and these may be used alone or in two kinds. The above can be mixed and used.

If the amount of the monomer (C) is too small, the effect of improving the recoat adhesion of the curable composition by using the monomer (C) cannot be sufficiently recognized. Therefore, if it is 0.5% by weight or more of the total amount of the copolymerization component, and is too much, the storage stability of the curable composition and the coating film formed by using the curable composition Since the weathering yellowing property becomes inferior, it is 10% by weight or less of the total amount of the copolymerization components. In order to further enhance the effect of improving the recoat adhesion of the curable composition, the amount of the monomer (C) blended is preferably 1% by weight or more and 5% by weight or less based on the total amount of the copolymerization components.

The vinyl copolymer used in the present invention is
It is obtained by polymerizing a copolymerization component containing the monomer (A), the monomer (B) and the monomer (C). In the present invention, other monomers copolymerizable with these monomers (hereinafter , Monomer (D)) can be used as a copolymerization component.

Examples of the monomer (D) 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,
(Meth) acrylamide, α-ethyl (meth) acrylamide, N-methyl (meth) acrylamide, N, N-
Dimethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, AS- which is a macromonomer
Compounds such as 6, AN-6, AA-6, AB-6, AK-5 (above, manufactured by Toa Gosei Chemical Industry Co., Ltd.), and α, β such as hydroxyalkyl esters of (meth) acrylic acid.
A vinyl compound containing a phosphoric acid ester group such as a condensation product of hydroxyalkyl esters of ethylenically unsaturated carboxylic acid and phosphoric acid or phosphoric acid esters, (meth) acrylate containing a urethane bond or a siloxane bond ( (Meth) acrylic acid derivatives, styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4
-Aromatic hydrocarbon vinyl compounds such as hydroxystyrene and vinyltoluene; unsaturated carboxylic acids such as maleic acid, fumaric acid and itaconic acid, salts thereof such as alkali metal salts, ammonium salts and amine salts; maleic anhydride etc. Unsaturated carboxylic acid anhydrides, esters of unsaturated carboxylic acids such as diesters or half esters of these with linear or branched alcohols having 1 to 20 carbon atoms; vinyl acetate, vinyl propionate, diallyl Vinyl esters such as phthalates and allyl compounds;
Amino group-containing vinyl compounds other than the above-mentioned monomer (C) such as vinyl pyridine and aminoethyl vinyl ether;
Amide group-containing vinyl compounds such as itaconic acid diamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone; methyl vinyl ether,
Other vinyl compounds such as cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide, N-vinyl imidazole, vinyl sulfonic acid and the like can be mentioned. These may be used alone or in combination of two or more.

In the present invention, among the above-mentioned monomers (D), amine, carboxylic acid, sulfonic acid,
When a polar monomer having a phosphoric acid group is used, it is desirable that the blending amount thereof be 5% by weight or less of the total amount of the copolymerization components in order to suppress the crosslinking reaction at the time of polymerization.

Further, in the present invention, for the purpose of improving the weather resistance, solvent resistance, impact resistance and the like of the coating film formed using the obtained curable composition, 50% of the obtained vinyl copolymer is used. The copolymerization component is included so that the segments formed by urethane bonds or siloxane bonds and the segments derived from the monomer (D) other than the (meth) acrylic acid derivative are contained in the main chain of the copolymer within a range of not more than 10 wt%. You may adjust.

The vinyl-based copolymer used in the present invention is
From the copolymerization component containing the monomer (A), the monomer (B), the monomer (C), and optionally the monomer (D), for example, JP-A-54-36395 and JP-A-57-36109. Japanese Patent Laid-Open No. 58-15
Although it can be produced by the method described in Japanese Patent Publication No. 7810, etc., it is particularly preferably produced by a solution polymerization method using an azo radical polymerization initiator such as azobisisobutyronitrile from the viewpoint of ease of synthesis. preferable.

The polymerization solvent used in the solution polymerization method is
It is not particularly limited as long as it is non-reactive, but is not particularly limited, for example, hydrocarbons such as toluene, xylene, n-hexane and cyclohexane; acetic acid esters such as ethyl acetate and butyl acetate; methanol, ethanol, isopropanol, n -Alcohols such as butanol; ethers such as ethyl cellosolve, butyl cellosolve, and cellosolve acetate; ketones such as methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, and acetone.

The polymerization solvent may be used alone or in combination of two or more kinds, but the total amount of the copolymerization components is 100.
If the amount of alcohols such as methanol and butanol in the composition of the polymerization solvent is too small relative to the parts (parts by weight, the same applies below), gelation may occur during polymerization. The total amount of copolymerization components is 100
It is preferable to adjust so that about 1 to 30 parts of alcohols are contained per part.

In the solution polymerization, if necessary, for example, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, (CH ₃ O) ₃ Si—S—S—S
_{i (OCH 3) 3, (} CH 3 O) 3 Si-S 8 -Si
The molecular weight of the vinyl copolymer obtained can be adjusted by using a chain transfer agent such as (OCH ₃ ) ₃ alone or in combination of two or more kinds. Particularly, when a chain transfer agent having an alkoxysilyl group in the molecule such as γ-mercaptopropyltrimethoxysilane is used, an alkoxysilyl group can be introduced at the terminal of the vinyl-based copolymer, which is preferable. . The amount of the chain transfer agent used is preferably about 0.1 to 10% by weight based on the total amount of the copolymerization components.

The value of the molar ratio of the alcoholic hydroxyl group to the hydrolyzable silyl group (alcoholic hydroxyl group / hydrolyzable silyl group) in the vinyl copolymer thus obtained is excellent in thermosetting, acid resistance, and weather resistance, or that they can sell the curable composition exhibiting water resistance et 0. 5 or more, particularly 0.7 or more, preferably or 2 or less, so that the value of such ratio is included within the range, is possible to adjust the amount of the monomer (A) and monomer (B) to be used preferable.

If the tertiary amino group equivalent (resin solid content (g) of vinyl copolymer containing 1 mol of tertiary amino group) in the vinyl copolymer is too small, Since the storage stability of the obtained curable composition tends to decrease, it is preferably 1500 g / mol or more, particularly 3000 g / mol or more, and when it is too large, the curable composition is The recoat adhesion of 4 tends to be insufficient, so 40,000 g /
It is preferably less than or equal to mol, especially less than or equal to 20000 g / mol.

Further, regarding the number average molecular weight of the vinyl-based copolymer, the curable composition obtained is excellent in thermosetting property, and the coating film formed by using the composition is excellent in physical properties such as durability. From that point, more than 1000, especially 2000
Further, it is preferably 30,000 or less, more preferably 25,000 or less.

Examples of the curing catalyst used in the present invention include organotin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate and tin octylate;
Phosphoric acid or phosphate such as phosphoric acid, 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, acryl glycidyl ether, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,
γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, formula:

[0068]

[Chemical 19]

Addition reaction product of an epoxy compound such as a compound represented by the following, Cardura E, Epicoat 828, Epicoat 1001 (all manufactured by Yuka Shell Epoxy Co., Ltd.) with phosphoric acid and / or monophosphate ester: isopropyltriiso Stearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate,
Organic titanate compounds such as bis (dioctyl pyrophosphate) oxyacetate titanate; organoaluminum compounds such as tris (ethylacetoacetate) aluminum and tris (acetylacetonato) aluminum; maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid , Citric acid, succinic acid, phthalic acid,
Saturated or unsaturated polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid and their acid anhydrides; acidic compounds such as dodecylbenzenesulfonic acid and paratoluenesulfonic acid; hexylamine, di-2-ethylhexylamine, N, Amines such as N-dimethyldodecylamine, dodecylamine, DABCO, DBU, morpholine and diisopropanolamine; for example NACURE 5
225, NACURE 5543, NACURE 59
25 (above, King Industries (KING
(Manufactured by INDUSTRIES)) and a reaction product of the above amines with an acidic phosphoric acid ester or an acidic compound; alkaline compounds such as sodium hydroxide and potassium hydroxide, and the like. These may be used alone or in combination of two or more. Can be used.

Among the curing catalysts, organotin compounds, acidic phosphoric acid esters, reaction products of the acidic phosphoric acid esters and amines, saturated or unsaturated polyvalent carboxylic acids, acid anhydrides of the polyvalent carboxylic acids. , Acidic compounds, reaction products of the acidic compounds with amines, organic titanate compounds, organic aluminum compounds and mixtures thereof are preferable from the viewpoint of high curing activity.

The curable composition for coating composition of the present invention can be obtained by stirring and mixing the vinyl copolymer and the curing catalyst with a stirrer or the like so as to obtain a uniform composition.

The mixing ratio of the vinyl copolymer and the curing catalyst is such that if the amount of the curing catalyst is too small, the curability of the resulting composition tends to decrease. The curing catalyst is preferably adjusted to 0.001 part or more, particularly 0.05 part or more with respect to 100 parts of the copolymer, and when the compounding amount of the curing catalyst is too large, Since the appearance of the coating film formed by using the curable composition tends to be deteriorated, the curing catalyst is added to 10 parts with respect to 100 parts of the vinyl copolymer.
It is preferable to adjust it so that it is not more than a part.

When it is desired to reduce the viscosity of the curable composition for coating materials of the present invention, organopolysiloxane silanol, tetraalkoxysilane, a partial hydrolyzate thereof, an amino resin such as a melamine resin and the like are used. , Preferably 50 parts or less relative to 100 parts of the vinyl-based copolymer,
More preferably, it may be added in the range of 30 parts or less.

The curable composition of the present invention contains an acrylic polyol, in order to improve the thermosetting property of the composition and the impact resistance of a coating film formed by using the composition.
A hydroxyl group-containing polymer compound such as polycarbonate diol or polyester diol is used, and the molar ratio of the alcoholic hydroxyl group to the hydrolyzable silyl group (alcoholic hydroxyl group / hydrolyzable silyl group) is within the range of 0.5 to 2 . It may be blended as described in 1.

By further adding a dehydrating agent and a solvent to the curable composition of the present invention, the storage stability of the curable composition can be further enhanced.

Examples of the dehydrating agent include ester compounds such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, ethyl silicate and methyl silicate, and hydrolyzable ester compounds such as methyltrimethoxysilane. These may be used alone or in admixture of two or more.

The dehydrating agent may be added at the time of polymerization of the vinyl-based copolymer or may be added after the polymerization. If the amount of the dehydrating agent is too large, the curing property is In a coating film formed using the composition, defects such as armpits (foaming phenomenon) tend to occur, so 70 parts or less, preferably 50 parts or less, and more preferably 100 parts or less relative to 100 parts of the vinyl-based copolymer, It is preferably 20 parts or less.

Examples of the solvent include alkyl alcohols having an alkyl group having 1 to 10 carbon atoms, and specific examples thereof include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n. -Butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-
Examples thereof include butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol and octyl alcohol.

The above-mentioned solvent such as alkyl alcohol may be used alone or in combination of two or more kinds, and the compounding amount thereof is not particularly limited, but when it is too much, the curable composition obtained is obtained. In the coating film formed by using, the defects such as armpits (foaming phenomenon) tend to occur easily, so it is usually 70 parts or less, preferably 50 parts or less, and more preferably 100 parts by weight with respect to 100 parts of the vinyl copolymer. Is preferably 20 parts or less, and when the solvent is used alone without using the dehydrating agent, the compounding amount is
Usually 0.5 parts or more based on 100 parts of the vinyl copolymer,
The amount is preferably 1 part or more, more preferably 2 parts or more, and 70 parts or less, preferably 50 parts or less, more preferably 20 parts or less.

When the dehydrating agent and the solvent are used in combination, as described above, the storage stability is further enhanced as compared with the curable composition comprising the vinyl copolymer and the curing catalyst. The compounding amount of the dehydrating agent and the solvent that expresses is a resin solid that is practically necessary for the curable composition in consideration of the molecular weight and composition of the vinyl copolymer and the curing catalyst in the curable composition of the present invention. It may be adjusted so as to have a concentration and a viscosity.

When the curable composition of the present invention is used as a coating material for a top coat, it is possible to further improve weather resistance by adding an ultraviolet absorber, a light stabilizer, etc., and especially when these are used in combination. Thereby, the weather resistance can be further improved.

Examples of the ultraviolet absorber include benzophenone-based, triazole-based, phenylsalicylate-based, diphenylacrylate-based, and acetophenone-based UV absorbers, which may be used alone or in combination of two or more. You can

Examples of the light stabilizer include bis (2,2,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-).
Piperidyl) sebacate, 2- (3,5-di-tert)
-Butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-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
-Butane tetracarboxylate and the like can be mentioned, and these can be used alone or in admixture of two or more kinds.

The amount of the ultraviolet absorber blended is usually 0.1 part or more, particularly 1 part or more, and 10 parts or less, and especially 5 parts or less with respect to 100 parts of the resin solid content of the curable composition. preferable. The amount of the light stabilizer is usually 0.1 part or more, particularly 1 part or more, and 10 parts or less with respect to 100 parts of the resin solid content of the curable composition,
It is preferably 5 parts or less.

Further, when the curable composition of the present invention is used as a clear coating for top coating, additives such as a diluent, an anti-cratering agent, a leveling agent; nitrocellulose,
A fibrin compound such as cellulose acetate butyrate; a resin such as an epoxy resin, a melamine resin, a vinyl chloride resin, a chlorinated polypropylene, a chlorinated rubber, polyvinyl butyral, or the like can be appropriately blended depending on the application.

The curable composition of the present invention has low toxicity,
It is also possible to adjust to a high solid having a resin solid content concentration of about 50 to 70% by weight. The curable composition of the present invention is applied to a substrate by a method such as spray coating, brush coating, roll coating or dip coating, and then cured by heating at about 80 to 160 ° C. to obtain acid resistance. It is possible to obtain a cured coating film having excellent chemical resistance, water resistance and weather resistance.

As described above, the curable composition for coating composition of the present invention exhibits excellent acid resistance, water resistance, weather resistance and thermosetting property, as well as excellent recoat adhesion property. It is suitable for use as a top coat paint for automobiles, industrial machines, steel furniture, interior and exterior of buildings, home appliances, plastics, etc., especially for automobiles.

Next, the curable composition for coating materials of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Production Examples 1 to 4 and Comparative Production Examples 1 to 4 (Production of Vinyl Copolymer) Solvesso 100 is placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas introducing pipe and a dropping funnel. (Exxon Chemical Co., Ltd., petroleum-based aromatic solvent) 26 parts was charged, and the temperature was raised to 110 ° C. while introducing nitrogen gas.
A mixture consisting of 4.75 parts of 2,2'-azobisisobutyronitrile having the composition shown in Table 1, 2 parts of methyl orthoacetate, 3.5 parts of Solvesso 100 and 2 parts of methanol was added from a dropping funnel. It was added dropwise at a constant rate over time.

After the addition of the mixture was completed, 0.25 parts of 2,2'-azobisisobutyronitrile and 10 parts of xylene were added dropwise at a constant rate over 30 minutes, polymerization was carried out for 1 hour and 30 minutes, and then the mixture was cooled. , 4 parts of methyl orthoacetate and 4 parts of methanol were added, and Solvesso 100 was further added to the resin solution to adjust the resin solid content concentration to 60% by weight.
A solution of vinyl copolymer was obtained.

Number average molecular weight and hydrolyzable silyl group equivalent of the obtained vinyl-based copolymer (resin solid content (g) of vinyl-based copolymer containing 1 mol of hydrolyzable silyl group)
(G / mol), alcoholic hydroxyl group equivalent (resin solid content (g) of vinyl-based copolymer containing 1 mol of alcoholic hydroxyl group) (g / mol), tertiary amino group equivalent (g / mol)
Table 1 shows the values of the molar ratio of the alcoholic hydroxyl group and the hydrolyzable silyl group (alcoholic hydroxyl group / hydrolyzable silyl group). The abbreviations of the vinyl copolymers are also shown in Table 1.

The abbreviations of the copolymerization components in Table 1 are as shown below.

MPTMSi: γ -methacryloxypropyltrimethoxysilane HPA: 2-hydroxypropyl acrylate HEMA: 2-hydroxyethyl methacrylate HEA: 2-hydroxyethyl acrylate DMAEMA: N, N-dimethylaminoethyl methacrylate ST: styrene MMA: methyl Methacrylate NBA: n-butyl acrylate

[0094]

[Table 1]

Examples 1 to 4 and Comparative Examples 1 to 4 For the resin solids of the vinyl copolymers obtained in Production Examples 1 to 4 and Comparative Production Examples 1 to 4, a leveling agent (Disparlon # 1984-) was used. 50, Kusumoto Kasei Co., Ltd.) 0.4
% By weight, 2% by weight of ultraviolet absorber (Tinuvin 900, manufactured by Ciba-Geigy Co., Ltd.) and light stabilizer (Tinuvin 44)
0, 1% by weight of Japan Ciba-Geigy Co., Ltd. and a mixture of dodecylbenzenesulfonic acid and diisopropanolamine as a curing catalyst (equivalent ratio: dodecylbenzenesulfonic acid / diisopropanolamine = 1 / 1.03)
1% by weight was added. This was diluted using Solvesso 100, and 4 Ford cup has a viscosity of 23-27
A clear paint for a top coat was prepared by adjusting the time to be 2 seconds.

Using the obtained clear coating for top coat, the retention of gel fraction and water-resistant gel fraction was examined according to the following method. The results are shown in Table 2.

(A) Gel Fraction The free clear film obtained by baking the clear coating material for top coat at 140 ° C. for 30 minutes was cut in half, and pre-weighed 200-mesh stainless steel wire netting (W ₀ ). It was packaged and weighed accurately (W ₁ ). This was immersed in acetone for 24 hours for extraction, dried, and precisely weighed (W ₂ ), and the gel fraction (wt%) was determined based on the following formula.

Gel fraction (% by weight) = {(W ₂ −W ₀ ) /
(W ₁ −W ₀ )} × 100 (b) Retention rate of water-resistant gel fraction The remaining half of the clear film produced at the time of (a) gel fraction measurement was made of a 300-mesh stainless steel precisely weighed in advance. Wrap it in a wire mesh (W ' ₀ ) and weigh it accurately (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 ), and the water-resistant gel fraction was calculated based on the following formula. (Wt%) was determined.

Water resistant gel fraction (% by weight) = {(W ' ₂ -W
′ ₀ ) / (W ′ ₁ −W ′ ₀ )} × 100 Using the value of the above-mentioned (a) gel fraction (% by weight) measured in advance for the same film, the water-resistant gel content is calculated based on the following formula. The retention rate (% by weight) was obtained.

Retention rate of water-resistant gel fraction (% by weight) = {(water-resistant gel fraction) / (gel fraction)} × 100 Next, a mild steel sheet subjected to degreasing and phosphorylation was applied to an epoxy resin for automobiles. A coated plate coated with an amide-based cationic electrodeposition primer and an intermediate surfacer was used as a test piece, and an acrylic melamine resin coating (silver metallic base) was applied as a base coat on the surface thereof. Next, the clear coating composition for the top coat was applied wet-on-wet, set for 10 minutes, and then baked at 140 ° C. for 30 minutes to form a coating film. The dry film thickness of the obtained coating film is about 15 for the base coat.
and the top coat clear was about 30 to 40 μm.

The acid resistance, recoat adhesion and weather resistance of the obtained coating film were examined according to the following methods. The results are shown in Table 2.

(C) Using an acid resistant pipette, 4 drops of 40% sulfuric acid aqueous solution was dropped on the coating film and heated at 70 ° C. for 30 minutes, and then the sulfuric acid aqueous solution was washed off with water to see how the coating surface changed. Visually,
It evaluated based on the following evaluation criteria.

(Evaluation Criteria) 10 points: No change compared to before dropping. 9 points: A slight change is recognized. 8 points: A circular mark remains. 7 points: Discoloration and swelling are slightly observed. 6 points: A slight decrease in gloss and a slight discoloration are observed. 5 points: A decrease in gloss and discoloration are clearly observed. 4 points: Slight shrinkage and clear swelling are observed. 3 points: slight lifting, severe shrinkage, and discoloration are observed. 2 points: Lifting is clearly recognized. 1 point: Dissolution of the coating film is observed.

(D) Recoat adhesion 2 mm in accordance with the cross-cut test method of JIS K 5400.
The surface state of the coating film cut into 25 grids of 2 mm x 2 mm was visually observed, and 25/25 was evaluated as 10 points and 0/25 was evaluated as 0 points. The larger the score, the better the recoating and adhesion.

(E) Weather resistance The yellowing and gloss retention as the weather resistance of the coating film were examined as follows.

(Yellow Degeneration) Using Yubucon manufactured by Atlas Co., a repeated operation was performed in which UV irradiation (FS40 lamp) was conducted at 70 ° C. for 8 hours, and then a warming state at 50 ° C. (no ultraviolet irradiation by the lamp) was conducted for 4 hours. The test was carried out for 1000 hours, and the color difference (ΔE) on the surface of the coating film before and after the test was measured using a color difference meter (Σ80) manufactured by Nippon Denshoku Industries Co., Ltd.

(Gloss retention) A test was conducted in the same manner as the yellowing, and the 60 ° gloss of the coating film surface before and after the test was measured using a gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. Based on this, the gloss retention rate (%) after the test was determined.

Gloss retention (%) = (gloss value after test / gloss value before test) × 100

[0109]

[Table 2]

From the results shown in Table 2, all the coating films formed by using the coating materials obtained in Examples 1 to 4 have a high retention rate of water-resistant gel fraction, excellent water resistance, and acid resistance. It has excellent acid resistance with almost no change in surface condition even when adhered, has a small yellowing, has a high gloss retention rate, and has excellent weather resistance, as well as excellent recoat adhesion. It can be seen that it is.

[0111]

The curable composition for coating composition of the present invention exhibits excellent acid resistance, water resistance, weather resistance and thermosetting property as well as excellent recoat adhesion, and has a good balance of these physical properties. Therefore, it can be suitably used as a top coat paint for automobiles, industrial machines, steel furniture, interior and exterior of buildings, home appliances, plastics and the like.

Continuation of front page (56) Reference JP 62-50366 (JP, A) JP 3-24148 (JP, A) JP 60-168769 (JP, A) JP 5-138112 (JP , A) JP-A-4-318088 (JP, A) International Publication 91/016383 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 5/00-201/10 C08L 1 / 00-101/16 C08F 230/08

Claims (4)

(57) [Claims] 1. A compound represented by the general formula (I): (In the formula, 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, R ³ has the general formula: (In the formula, R ⁴ represents a hydrogen atom or a methyl group) or a vinyl-based monomer containing a hydrolyzable silyl group represented by —CH ₂ — and a represents 0, 1 or 2. Body (A) 5 to 40% by weight, alcoholic hydroxyl group-containing vinyl monomer (B) 5 to 50% by weight, and tertiary amino group-containing vinyl monomer (C) 0.5 to 10% by weight Alcoholic hydroxyl group formed by polymerizing
To hydrolyzable silyl group (alcoholic hydroxyl group
A curable composition for coatings , comprising a vinyl copolymer having a value of (/ hydrolyzable silyl group) of 0.5 to 2 and a curing catalyst. 2. A vinyl monomer containing a tertiary amino group (C)
But N, N-dialkylaminoalkyl (meth) acrylate in which claim 1 Symbol placement for coatings curable composition. 3. The vinyl copolymer comprises 20 to 31.1% by weight of a vinyl monomer (A) containing a hydrolyzable silyl group, and an alcoholic hydroxyl group-containing vinyl monomer (B) 1
1.8 to 25.9% by weight, tertiary amino group-containing vinyl monomer (C) 1 to 4% by weight, and other copolymerizable monomer (D) 41 to 65.7% by weight by polymerizing the copolymer component composed of a vinyl copolymer comprising claim 1
Paints curable composition or 2 wherein. 4. A tertiary amino group equivalent of the vinyl copolymer is 1500～40000G / mol, claim a number average molecular weight of 1,000 to 30,000 1, 2 or 3 paints curable described Composition.