JP3347879B2 - Curable composition for paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a curable composition for coatings. More specifically, it can be suitably used, for example, as an overcoat used for automobiles, industrial machines, steel furniture, building interiors and exteriors, home appliances, plastics, etc., and is particularly excellent in acid resistance, water resistance, and thermosetting. The present invention relates to a curable composition for coatings which exhibits properties and the like, has a long pot life, and can be suitably used for an overcoat for automobiles.

[0002]

2. Description of the Related Art Conventionally, coatings containing melamine resins such as alkyd melamine and acrylic melamine have been used for coating automobiles, building interiors and exteriors, industrial machines, steel furniture, plastics, and the like. 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 affected by acid rain.

[0003] 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 appearing on coating films have been observed.

In order to solve the above problems, the present inventors have proposed a vinyl copolymer having a hydrolyzable silyl group or a blend of a vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol. As a result of studying the use of a copolymer of a vinyl monomer having a hydrolyzable silyl group and a vinyl monomer having an alcoholic hydroxyl group as a paint, when these are used, They have found that a curable resin for coatings having excellent acid resistance and weather resistance can be obtained, and have already filed a patent application (JP-A-63-132977).

The above-mentioned vinyl copolymer having a hydrolyzable silyl group, a blend 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 a copolymer of a vinyl monomer having an alcoholic hydroxyl group and a vinyl monomer having an alcoholic hydroxyl group is that the hydrolyzable silyl group and the alcoholic hydroxyl group form a stable siloxane bond or siloxy bond and are cured, so that acrylic melamine or alkyd is used. This means that a coating film having better acid resistance and weather resistance can be formed as compared with the case where a melamine resin such as melamine is used, and the hydrolyzable silyl group has a general formula (II):

[0006]

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Wherein R ⁵ is an alkyl group having 1 to 10 carbon atoms, and 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. A hydrogen group, b represents 0, 1 or 2).
Since it is introduced into the main chain of the copolymer via a C bond, a coating film having excellent acid resistance and weather resistance can be formed.

[0008] The blend system of the vinyl copolymer having a hydrolyzable silyl group and an acrylic polyol certainly has excellent thermosetting properties and appearance and is a relatively expensive raw material. Since the amount of the compound having a group can be reduced, there is an advantage that the cost can be reduced as a curable composition, but on the other hand,
The blend system is not excellent in water resistance and acid resistance. In order to further improve the compatibility between the vinyl copolymer having a hydrolyzable silyl group and the acrylic polyol, the molecular weight and the molecular weight of each polymer are required. There remains a problem that the composition of the polymerizable compound and the blend ratio are limited to some extent.

In order to solve the above-mentioned problems, the present inventors have used a vinyl copolymer having a hydrolyzable silyl group and an alcoholic hydroxyl group in the same molecule to achieve a remarkable improvement in acid resistance. Propose that.

[0010] However, the vinyl copolymer having the hydrolyzable silyl group and the alcoholic hydroxyl group in the same molecule certainly exhibits excellent water resistance and acid resistance, but has a sufficient pot life. Not something.

[0011]

Accordingly, the present inventors have been keen to provide a coating composition which exhibits excellent acid resistance, water resistance and thermosetting properties in view of the above prior art and has a long pot life. As a result of repeated studies, they have found such a curable composition for a paint, and have completed the present invention.

[0012]

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

[0013]

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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, R ³ has the general formula:

[0015]

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(Wherein, R ⁴ represents a hydrogen atom or a methyl group) or a vinyl containing a hydrolyzable silyl group represented by -CH _2- , a represents 0, 1 or 2. It contains 5 to 40% by weight of a monomer (A), 5 to 50% by weight of an alcoholic hydroxyl group-containing vinyl monomer (B), and 1 to 20% by weight of an amide group-containing vinyl monomer (C). The present invention relates to a curable composition for paints, which comprises a vinyl copolymer obtained by polymerizing a copolymer component and a curing catalyst.

[0017]

Action and Examples The curable composition for paints of the present invention comprises:
As mentioned above, the general formula (I):

[0018]

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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, R ³ has the general formula:

[0020]

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(Wherein R ⁴ represents a hydrogen atom or a methyl group) or vinyl containing a hydrolyzable silyl group represented by -CH _2- , a represents 0, 1 or 2. (A) 5 to 40% by weight, alcoholic hydroxyl group-containing vinyl monomer (B) 5 to 50% by weight, and amide group-containing monomer (hereinafter referred to as hydrolyzable silyl group-containing vinyl monomer) 1-20% by weight of vinyl monomer (C)
A paint -based hardener characterized by blending a vinyl copolymer obtained by polymerizing a copolymer component containing styrene and a curing catalyst.
Composition (Claim 1), Alcohol in Vinyl Copolymer
Molar ratio of hydroxyl group to hydrolyzable silyl group (alcohol
Hydroxyl group / hydrolyzable silyl group) of 0.1 to 3
The curable composition for a coating according to claim 1, which is
2) The amide group-containing vinyl monomer (C) is N-methylo
3. The paint according to claim 1, which is acrylacrylamide.
Curable composition (claim 3) and a vinyl copolymer
Containing a hydrolyzable silyl group represented by the general formula (I)
20 to 31.1% by weight of vinyl monomer (A), alcohol
Hydroxyl group-containing vinyl monomer (B) 13.3 to 25.
9% by weight, amide group-containing vinyl monomer (C) 3 to 10
Wt% and other monomers copolymerizable with them
(D) a copolymer component containing 40 to 63.7% by weight
A vinyl copolymer obtained by combining the two or more.
4. The curable composition for paints according to claim 3 (Claim 4), and vinyl
The amide group equivalent of the toluene-based copolymer is 350 to 20,000 g /
Mole, and the number average molecular weight is 1,000 to 30,000.
The curable composition for a paint according to claim 1, 2, 3, or 4.
Related to (claim 5).

In the present invention, a hydrolyzable silyl group-containing vinyl monomer (A) represented by the general formula (I) is used as a copolymer component for obtaining a vinyl copolymer. In the monomer (A), since the silicon atom bonded to the hydrolyzable group is via the Si—C bond, 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 alcoholic hydroxyl group in the vinyl monomer (B) reacts with the hydrolyzable silyl group to form: The resulting curable composition exhibits excellent thermosetting properties. Further, an amide group-containing vinyl monomer (C) is used as a copolymer component, and the pot life extension effect of the curable composition obtained by the amide group in the vinyl monomer (C) is reduced. Be recognized.

The vinyl copolymer used in the present invention is:
Thus, since it has a hydrolyzable silyl group, alcoholic hydroxyl group and amide group in the same molecule,
When the vinyl copolymer is used, a curable composition exhibiting excellent acid resistance, water resistance and thermosetting properties and having a long pot life can be obtained.

In the general formula (I) of the hydrolyzable silyl group-containing vinyl monomer (A) (hereinafter referred to as monomer (A)) represented by the general formula (I), an alkyl group represented by R ¹ If the number of carbon atoms is too large, the reactivity of the hydrolyzable silyl group will decrease, so that R ¹ is an alkyl group having 1 to 10 carbon atoms, preferably, for example, 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 as exemplified in the aforementioned R ¹ , preferably an aryl group having 6 to 25 carbon atoms such as a phenyl group and a benzyl group and the like Is 1 selected from the group consisting of aralkyl groups having 7 to 12 carbon atoms
Among these, an alkyl group having 1 to 4 carbon atoms is preferable in that the obtained composition has excellent curability.

As the monomer (A), for example,

[0027]

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General formula (III) such as:

[0029]

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Wherein R ¹ , R ² , R ⁴ and a are the same as defined above;

[0031]

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Formula (IV) such as:

[0033]

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Wherein R ¹ , R ² and a are the same as above, R ⁷ is a hydrogen atom or a methyl group, and n is an integer of 1 to 12;

[0035]

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General formula (V) such as:

[0037]

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(Wherein R ¹ , R ² , R ⁷ , a and n are the same as those described above);

[0039]

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General formula (VI) such as:

[0041]

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Wherein R ¹ , R ² , R ⁷ and a are the same as above, and m is an integer of 1 to 8;

[0043]

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(Wherein p is an integer of 0 to 20), such as general formula (VII):

[0045]

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Wherein R ¹ , R ² , R ⁷ and a are the same as above and q is an integer of 0 to 20; and a hydrolyzable silyl compound represented by the general formula (I) (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. Among them, handling is easy and low The compound represented by the general formula (IV) is preferable because it is expensive and does not produce a reaction by-product.

When the amount of the monomer (A) is too small, the acid resistance of a coating film formed using the obtained curable composition becomes insufficient.
If it is 5% by weight or more of the total amount of the copolymer component, and if it is too much, the pot life of the curable composition will be shortened, so it is 40% by weight or less of the total amount of the copolymer component. In order to obtain a curable composition exhibiting even better thermosetting properties, acid resistance, weather resistance, etc., the amount of the monomer (A) is at least 10% by weight of the total amount of the copolymer components.
Further, it is preferably at most 35% by weight.

Examples of the alcoholic hydroxyl group-containing vinyl monomer (B) (hereinafter referred to as monomer (B)) include 2-hydroxyethyl (meth) acrylate,
-Hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, Alonix 5700 (manufactured by Toa Gosei Chemical Industry Co., Ltd.), 4-hydroxystyrene, HE-
10, acrylate oligomers having a hydroxyl group at the terminal such as HE-20, HP-1, HP-20 (the above,
Nippon Shokubai Chemical Co., Ltd.), Blemmer PP series (polypropylene glycol methacrylate), Blemmer PE series (polyethylene glycol monomethacrylate), Blemmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Blemmer AP-400 (polypropylene glycol monoacrylate) , Blenmer AE-350 (polyethylene glycol monoacrylate), Blenmer NKH-5050 (polypropylene glycol polytrimethylene monoacrylate), Blenmer GLM (glycerol monomethacrylate), etc. (all manufactured by NOF Corporation), hydroxyl group-containing vinyl Ε-caprolactone-modified hydroxyal obtained by the reaction of a series compound with ε-caprolactone And a kill vinyl copolymerizable compound.

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

[0050]

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(Wherein R ⁸ is a hydrogen atom or a methyl group,
r represents an integer of 1 or more).
Accel FA-1 (R ⁸ is a hydrogen atom, n is 1), and Placel FA-4 (R ⁸ is a hydrogen atom, n
Represents 4), Placel FM-1 (R ⁸ represents a methyl group, n represents 1), Placel FM-4 (R ⁸
Is a methyl group, n is 4) (the above are manufactured by Daicel Chemical Industries, Ltd.), and TONEM-100 (R ⁸ is a hydrogen atom, n
Represents 2), TONE M-201 (R ⁸ represents a methyl group, n represents 1) (all manufactured by UCC) and the like.

The monomers (B) can be used alone or in combination of two or more. Among them, the acid resistance and the water resistance of the coating film formed using the obtained curable composition can be used. 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and ε-caprolactone-modified hydroxyalkyl vinyl copolymerizable compound are preferred from the viewpoint of excellent properties.

If the amount of the 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 copolymer components. If the amount is too large, the coating film formed using the curable composition is inferior in water resistance and acid resistance and becomes insufficient. It is. In addition, in order to obtain a curable composition exhibiting more excellent thermosetting properties and flexibility,
The compounding amount of the monomer (B) is more preferably 6% by weight or more, preferably 7% by weight or more, and 40% by weight or less, preferably 35% by weight or less of the total amount of the copolymer components.

The amide group-containing vinyl monomer (C)
(Hereinafter referred to as monomer (C)) include, for example, (meth) acrylamide, α-ethyl (meth) acrylamide, N-methyl (meth) acrylamide, N, N-
Dimethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth)
N-alkoxymethyl (meth) acrylamide such as acrylamide, Nn-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, and (meth) such as N-methylol (meth) acrylamide ) Acrylamide; p-styrenesulfonamide, N-methyl-p-
Sulfonamides such as styrenesulfonamide and N, N-dimethyl-p-styrenesulfonamide; and itaconic diamide, maleic diamide, fumaric diamide, crotonamide, N-vinylpyrrolidone, and the like.
These can be used alone or as a mixture of two or more. Among them, N- is preferred because the resulting composition maintains good curability and has a large pot life extending effect. Methylol (meth) acrylamide and Nn-butoxymethyl (meth) acrylamide are preferred, and N-methylolacrylamide is particularly preferred.

When the amount of the monomer (C) is too small, the effect of extending the pot life of the curable composition due to the use of the monomer (C) cannot be sufficiently recognized. Therefore, it is 1% by weight or more of the total amount of the copolymer components, and if it is too much,
Since the solubility during the polymerization is lowered and problems such as the inability to stably carry out the polymerization occur, the content is 20% by weight or less of the total amount of the copolymer components. In order to further enhance the pot life extending effect of the curable composition, the amount of the monomer (C) is preferably 10% by weight or less of the total amount of the copolymer components.

The vinyl copolymer used in the present invention is:
It is obtained by polymerizing a copolymer component containing the monomer (A), the monomer (B) and the monomer (C). In the present invention, other monomers copolymerizable with these monomers (hereinafter, referred to as the following). , 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, and stearyl (meth) acrylate. Acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile, glycidyl (meth) acrylate, dimethyl Aminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, macromonomers AS-6, AN-6, AA-6, AB-6, AK-5
Such as (the above, manufactured by Toa Gosei Chemical Industry Co., Ltd.),
Phosphoric ester group-containing vinyl compounds such as condensation products of hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyalkyl esters of (meth) acrylic acid and phosphoric acid or phosphoric esters. (Meth) acrylic acid derivatives such as (meth) acrylates containing urethane bonds and siloxane bonds, and aromatic hydrocarbons such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene and vinyltoluene Vinyl compounds; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid; salts thereof such as alkali metal salts, ammonium salts and amine salts; acid anhydrides of unsaturated carboxylic acids such as maleic anhydride; Diester with alcohol having linear or branched chain of number 1 to 20 Or an ester of an unsaturated carboxylic acid such as a half ester; a vinyl ester or an allyl compound such as vinyl acetate, vinyl propionate or diallyl phthalate; an amino group-containing vinyl compound such as vinyl pyridine or aminoethyl vinyl ether; a methyl vinyl ether or cyclohexyl vinyl ether , Vinyl chloride,
Vinylidene chloride, chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide, N-
Examples thereof include other vinyl compounds such as vinyl imidazole and vinyl sulfonic acid. These compounds can be used alone or in combination of two or more by appropriately adjusting the amount thereof.

In the present invention, among the monomers (D), amines, carboxylic acids, sulfonic acids,
When a polar monomer having a phosphoric acid group is used, it is desirable that the amount of the polar monomer be 5% by weight or less based on the total amount of the copolymer components in order to suppress a crosslinking reaction at the time of polymerization.

In the present invention, in order to improve the weather resistance, solvent resistance, impact resistance, and the like of the coating film formed using the obtained curable composition, the obtained vinyl copolymer may be used. Within a range not exceeding the weight percent, the copolymer component is added so that a segment formed by a urethane bond or a siloxane bond or a segment derived from a monomer (D) other than the (meth) acrylic acid derivative is included in the main chain of the copolymer. It may be adjusted.

The vinyl copolymer used in the present invention is:
From the copolymer components containing the monomer (A), the monomer (B), the monomer (C) and, if necessary, the monomer (D), for example, JP-A-54-36395, JP-A-57-36109 Gazette, JP-A-58-15
Although it can be produced by the method described in, for example, No. 7810, it can be 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 as follows:
Non-reactive ones may be used, and there is no particular limitation. For example, hydrocarbons such as toluene, xylene, n-hexane and cyclohexane; acetates 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 above-mentioned polymerization solvents can be used alone or in combination of two or more.
If the amount of alcohols such as methanol or butanol in the polymerization solvent composition is too small relative to parts (parts by weight, the same applies hereinafter), gelation may occur during polymerization. Has a total amount of copolymer components of 100
It is preferable to adjust so that about 1 to 30 parts of alcohol is 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
By using a chain transfer agent such as (OCH ₃ ) ₃ alone or as a mixture of two or more, the molecular weight of the obtained vinyl copolymer can be adjusted. In particular, 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 copolymer, which is preferable. . The use amount of such a chain transfer agent is preferably about 0.1 to 10% by weight of the total amount of the copolymer components.

The value of the molar ratio of alcoholic hydroxyl groups to hydrolyzable silyl groups (alcoholic hydroxyl groups / hydrolyzable silyl groups) in the vinyl copolymer thus obtained is excellent in thermosetting, acid resistance, From the viewpoint that a curable composition exhibiting weather resistance, water resistance and the like can be obtained, 0.1 or more, preferably 0.5 or more, particularly 0.7 or more, and 3
Hereinafter, it is preferably 2.5 or less, particularly preferably 2 or less, and the amounts of the monomers (A) and (B) used are preferably adjusted so that the value of the ratio falls within the above range.

When the amide group equivalent (the resin solid content (g) of the vinyl copolymer containing 1 mol of amide group) in the vinyl copolymer is too small, the vinyl copolymer 350 g / mol or more, especially 1000 g, because the viscosity of the coalescence tends to be too high
/ Mol or more is preferable, and when it is too large, the effect of extending the pot life in the obtained curable composition tends not to be sufficiently exhibited, so that it is 20,000 g / mol or less, especially 10,000 g.
/ Mol or less.

Further, the number average molecular weight of the vinyl copolymer is such that the obtained curable composition has excellent thermosetting properties, and the coating film formed by using the composition has excellent properties such as durability. From that point, more than 1000, especially 2000
It is preferably at least 30,000, especially at most 25,000.

The curing catalyst used in the present invention includes, for example, organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate and tin octylate;
Phosphoric acid or phosphate esters 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, acrylic glycidyl ether, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,
γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, formula:

[0068]

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Addition reaction product of an epoxy compound such as a compound represented by the formula: Cardura E, Epikote 828, Epikote 1001 (all manufactured by Yuka Shell Epoxy Co., Ltd.) with phosphoric acid and / or monophosphate; Stearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate,
Organic titanate compounds such as bis (dioctyl pyrophosphate) oxyacetate titanate; organic aluminum 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 polycarboxylic acids such as trimellitic acid and pyromellitic acid and their anhydrides; acidic compounds such as dodecylbenzenesulfonic acid and paratoluenesulfonic acid; hexylamine, di-2-ethylhexylamine, N, Amines such as N-dimethyldodecylamine, dodecylamine, DABCO, DBU, morpholine, diisopropanolamine; for example, NACURE 5
225, NACURE 5543, NACURE 59
25 (King Industries, Inc. (KING
INDUSTRIES) and the like, and a reaction product of the above-mentioned amines with an acidic phosphoric acid ester or an acidic compound; alkaline compounds such as sodium hydroxide, potassium hydroxide and the like; and these may be used alone or in combination of two or more. Can be used.

Among the above-mentioned curing catalysts, an organotin compound, an acidic phosphoric acid ester, a reaction product of the acidic phosphoric acid ester with an amine, a saturated or unsaturated polycarboxylic acid, and an acid anhydride of the polycarboxylic acid , An acidic compound, a reaction product of the acidic compound with an amine, an organic titanate compound, an organic aluminum compound, and a mixture thereof are preferable because of high curing activity.

The curable composition for a coating material of the present invention can be obtained by stirring and mixing the vinyl copolymer and the curing catalyst so as to have a uniform composition using, for example, a stirrer.

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 amount of the curing catalyst is preferably adjusted to be 0.001 part or more, especially 0.05 part or more, based on 100 parts of the system copolymer, and when the amount of the curing catalyst is too large, Since the appearance of the coating film formed by using the curable composition tends to decrease, the curing catalyst is used in an amount of 10 parts per 100 parts of the vinyl copolymer.
It is preferable to adjust so as to be less than or equal to parts.

In order to reduce the viscosity of the curable composition for coatings of the present invention, an organopolysiloxane silanol or tetraalkoxysilane, a partial hydrolyzate thereof, or an amino resin such as a melamine resin may be used. , Preferably 50 parts or less based on 100 parts of the vinyl copolymer,
More preferably, it may be blended in a range of 30 parts or less.

The curable composition of the present invention contains acrylic polyol, in order to improve the thermosetting property of the composition and the impact resistance of a coating film formed using the composition.
A hydroxyl group-containing polymer compound such as polycarbonate diol and polyester diol is prepared by adjusting the molar ratio of alcoholic hydroxyl group to hydrolyzable silyl group (alcoholic hydroxyl group / hydrolyzable silyl group) within the range of 0.1 to 3. May be blended as described above.

By further adding a dehydrating agent and a solvent to the curable composition of the present invention, the effect of extending the pot life 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 can be used alone or in combination of two or more.

The dehydrating agent may be blended at the time of polymerization of the vinyl copolymer or may be blended after the polymerization. If the amount of the dehydrating agent is too large, the curability obtained is too large. In a coating film formed by using the composition, defects such as waki (foaming phenomenon) tend to occur easily. Therefore, 70 parts or less, preferably 50 parts or less, and more preferably 100 parts or less with respect to 100 parts of the vinyl copolymer. Preferably, it is 20 parts or less.

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

The above-mentioned solvents such as alkyl alcohols can be used alone or as a mixture of two or more kinds. The amount of the solvent is not particularly limited, but if it is too large, the resulting curable composition can be used. In the coating film formed by using, there is a tendency that defects such as waki (foaming phenomenon) are liable to occur. Therefore, the coating amount is usually 70 parts or less, preferably 50 parts or less, more preferably 100 parts of the vinyl copolymer. Is desirably 20 parts or less, and when the solvent is used alone without using the dehydrating agent, the compounding amount is
Usually 0.5 part or more with respect to 100 parts of the vinyl copolymer,
The content is preferably at least 1 part, more preferably at least 2 parts, and at most 70 parts, preferably at most 50 parts, more preferably at most 20 parts.

When the dehydrating agent and the solvent are used in combination, as described above, the pot life extending effect is further enhanced as compared with the curable composition comprising the vinyl copolymer and the curing catalyst. The amounts of the dehydrating agent and the solvent that exhibit various effects are considered 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. What is necessary is just to adjust so that it may have resin solid content concentration, viscosity, etc.

When the curable composition of the present invention is used as a top coating, the weather resistance can be further improved by blending an ultraviolet absorber, a light stabilizer and the like. 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 ones. These may be used alone or in combination of two or more. Can be.

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)
Bis (1,2,2,6,6-pentamethyl-4) -butyl-4-hydroxybenzyl) -2-n-butylmalonate
-Piperidyl), tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6)
6-pentamethyl-4-piperidyl) -1,2,3,4
-Butanetetracarboxylate and the like, and these can be used alone or in combination of two or more.

The compounding amount of the ultraviolet absorber is usually 0.1 part or more, preferably 1 part or more, more preferably 10 parts or less, especially 5 parts or less based on 100 parts of the resin solid content of the curable composition. preferable. The compounding amount of the light stabilizer is usually 0.1 part or more, preferably 1 part or more, and more preferably 10 parts or less, based on 100 parts of the resin solid content of the curable composition.
Especially, it is preferably 5 parts or less.

Further, when the curable composition of the present invention is used as a clear coating for overcoating, additives such as a diluent, an anti-cissing agent and a leveling agent;
A fibrous 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, and a polyvinyl butyral can be appropriately compounded 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. Further, the curable composition of the present invention is applied to a substrate by a method such as spray coating, brush coating, roll coating, dip coating and the like, and then cured by heating at about 80 to 160 ° C., for example, acid resistance. A cured coating film having excellent chemical resistance, water resistance, weather resistance and the like can be obtained.

As described above, the curable composition for paints of the present invention has a long pot life and exhibits excellent coating properties, and is therefore suitable for use in automobiles, industrial machines, steel furniture, building interior and exterior, It is suitable for use as a topcoat for home appliances and plastics, especially for automotive topcoats.

Next, the curable composition for paints of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to only these Examples.

Production Examples 1-4 and Comparative Production Examples 1-4 (Production of vinyl copolymer) Solvesso 100 was placed in a reaction vessel equipped with a stirrer, thermometer, reflux cooler, nitrogen gas inlet tube and dropping funnel. (Exxon Chemical Co., Ltd., petroleum-based aromatic solvent) 26 parts were charged and heated to 110 ° C. while introducing nitrogen gas.
Copolymerization components having the composition shown in Table 1, 2,2'-azobisisobutyronitrile, 4.75 parts, Solvesso 100 3.5
And a mixture consisting of 2 parts of methanol and 2 parts of methanol were dropped at a constant speed from the dropping funnel over 4 hours.

After the addition of the mixture was completed, 0.25 part of 2,2'-azobisisobutyronitrile and 10 parts of xylene were added dropwise at a constant speed over 30 minutes, and polymerization was carried out for 1 hour and 30 minutes, followed by cooling. , 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 solids concentration to 60% by weight.
A solution of a vinyl copolymer was obtained.

Number average molecular weight and hydrolyzable silyl group equivalent of the obtained vinyl copolymer (resin solid content (g) of vinyl copolymer containing 1 mol of hydrolyzable silyl group)
(G / mol), alcoholic hydroxyl group equivalent (resin solid content of vinyl copolymer containing 1 mol of alcoholic hydroxyl group (g)) (g / mol), amide group equivalent (g / mol) and alcoholic hydroxyl group Table 1 shows the value of the molar ratio to the hydrolyzable silyl group (alcoholic hydroxyl group / hydrolyzable silyl group). Table 1 also shows abbreviations of the respective vinyl copolymers.

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

MPTMSi: γ -methacryloxypropyltrimethoxysilane HPA: 2-hydroxypropyl acrylate HEMA: 2-hydroxyethyl methacrylate NBMAA: Nn-butoxymethylacrylamide NMAA: N-methylolacrylamide ST: Styrene MMA: Methyl methacrylate NBA : N-butyl acrylate

[0094]

[Table 1]

Examples 1 to 5 and Comparative Examples 1 to 5 The vinyl copolymers obtained in Production Examples 1 to 4 and Comparative Production Examples 1 to 4 were blended so as to have the composition shown in Table 2. 0.4% by weight of a leveling agent (Disparon # 1984-50, manufactured by Kusumoto Kasei Co., Ltd.) and a mixture of dodecylbenzenesulfonic acid and diisopropanolamine as a curing catalyst (equivalent ratio: dodecylbenzenesulfone) Acid / diisopropanolamine = 1 /
1.03) 1% by weight was added. This is Solvesso 100
And diluted with No. A clear paint for a top coat was prepared by adjusting the viscosity with a 4 Ford cup to 23 to 27 seconds.

Using the obtained clear coating for top coat, the retention of the gel fraction and the water-resistant gel fraction were examined in accordance with the following methods. Table 2 shows the results.

(A) Gel Fraction A clear coating film for top coat was baked at 140 ° C. for 30 minutes, the free clear film obtained was cut in half, and a 200-mesh stainless steel wire mesh (W ₀ ) that was precisely weighed in advance was weighed. And weighed accurately (W ₁ ). This was immersed in acetone for 24 hours to extract, dried, weighed accurately (W ₂ ), and the gel fraction (% by weight) was determined based on the following equation.

Gel fraction (% by weight) = ｛(W ₂ −W ₀ ) /
(W ₁ −W ₀ )｝ × 100 (b) Retention rate of water-resistant gel fraction (a) The other half of the clear film produced at the time of measuring the gel fraction is made of 300 mesh stainless steel which is precisely weighed in advance. Wrapped in a wire mesh (W ′ ₀ ) and precisely weighed (W ′
₁ ). This was immersed in water at 80 ° C. for 24 hours, taken out, further immersed in acetone for 24 hours, extracted, dried and weighed (W ′ ₂ ), and the water-resistant gel fraction was calculated based on the following equation. (% By weight).

Water resistant gel fraction (% by weight) = ｛(W ′ ₂ −W
' ₀ ) / (W' ₁ -W ' ₀ )｝ × 100 Using the value of the gel fraction (% by weight) previously measured for the same film, based on the following formula, The percentage retention (% by weight) was determined.

Retention rate of water-resistant gel fraction (% by weight) = {(water-resistant gel fraction) / (gel fraction)} × 100 A coated plate coated with an amide-based cationic electrodeposition primer and an intermediate coated surfacer was used as a test piece, and an acrylic melamine resin paint (black) was applied as a base coat on the surface thereof. Next, the clear coating material for the top coat was applied by wet-on-wet, and set for 10 minutes.
The coating was formed by baking for 0 minutes. The dry film thickness of the obtained coating film was about 15 µm for the base coat and about 30 to 40 µm for the top coat clear.

The acid resistance of the obtained coating film was examined according to the following method. Table 2 shows the results.

(C) Using an acid-resistant pipette, four drops of a 40% aqueous sulfuric acid solution were dropped on the coating film and heated at 70 ° C. for 30 minutes. Then, the sulfuric acid aqueous solution was washed off with water to see how the surface of the coating film changed. Observe visually,
The evaluation was made based on the following evaluation criteria.

(Evaluation Criteria) 10 points: No change compared to before dropping. 9 points: slight change is observed. 8 points: A circular mark remains. 7 points: Discoloration and swelling are slightly observed. 6 points: Slight decrease in gloss and discoloration are observed. 5 points: Decrease in gloss 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 recognized. 1 point: Dissolution of the coating film is observed.

Further, in the same manner as described above, a vinyl copolymer was blended so as to have the composition shown in Table 2, and 0.4% by weight of a leveling agent and 1% by weight of a curing catalyst based on the solid content of the resin. Was added. This was diluted to a state where it could be applied using Solvesso 100 to prepare a coating.

Using the obtained paint, the pot life was examined according to the following method. Table 2 shows the results.

(D) Pot life The paint was allowed to stand at room temperature in a completely open system, and the number of days until skin burr occurred on the surface was examined.

SH6018 in Table 2 is a silanol-containing phenyl-substituted cyclic organopolysiloxane (manufactured by Dow Corning Toray Silicone Co., Ltd.).

[0108]

[Table 2]

From the results shown in Table 2, all the coating films formed using the coating materials obtained in Examples 1 to 5 have a high retention of the water-resistant gel fraction, are excellent in water resistance, and Even if the acid adheres, the surface state hardly changes, and it is excellent in acid resistance, and at the same time, the pot life is remarkably extended as compared with the case where the paint obtained in Comparative Examples 1 to 5 is used. It turns out that it is a thing.

[0110]

The curable composition for paints of the present invention exhibits excellent acid resistance, water resistance and thermosetting properties and has a very long pot life, so that it can be used, for example, in automobiles, industrial machines, steel furniture, and the like. It can be suitably used as an overcoat used for interior and exterior of buildings, home appliances, plastics and the like.

Continuation of the front page (56) References JP-A-60-168696 (JP, A) JP-A-62-50366 (JP, A) JP-A-4-337376 (JP, A) JP-A-58-157810 (JP, A) JP-A-3-24148 (JP, A) JP-A-60-44552 (JP, A) JP-A-5-25423 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) C09D 143/04 C09D 133/00-133/26

Claims (5)

(57) [Claims] 1. A compound of the general formula (I): (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, R ³ is a general formula: (Wherein, R ⁴ represents a hydrogen atom or a methyl group) or —CH ₂ —, and a represents 0, 1 or 2, and a vinyl monomer containing a hydrolyzable silyl group represented by the formula: A copolymer component containing 5 to 40% by weight of the polymer (A), 5 to 50% by weight of an alcoholic hydroxyl group-containing vinyl monomer (B) and 1 to 20% by weight of an amide group-containing vinyl monomer (C) A curable composition for paints, characterized by containing a vinyl copolymer obtained by polymerizing the above and a curing catalyst. 2. The vinyl copolymer according to claim 1, wherein the molar ratio between the alcoholic hydroxyl group and the hydrolyzable silyl group (alcoholic hydroxyl group / hydrolyzable silyl group) is 0.1 to 3. Curable composition for paints. 3. An amide group-containing vinyl monomer (C) comprising N
-The curable composition for paint according to claim 1 or 2, which is methylol acrylamide. 4. A vinyl copolymer represented by the general formula (I):
Vinyl monomers containing hydrolyzable silyl groups
(A) 20 to 31.1% by weight, containing alcoholic hydroxyl group
13.3 to 25.9% by weight of vinyl monomer (B),
Group-containing vinyl monomer (C) in an amount of 3 to 10% by weight and
Other monomers (D) copolymerizable with them 40 to 63.
Vinyl based polymer obtained by polymerizing a copolymer component containing 7% by weight
Copolymerization The curing for paint according to claim 1, 2 or 3, which is a body.
Composition. 5. An amide group equivalent of the vinyl copolymer is 35.
0 to 20000 g / mol and a number average molecular weight of 100
The method according to claim 1, 2, 3, or 4, wherein the molecular weight is 0 to 30,000.
Curable composition for paints.