JPH07310053A - Curable composition for coating - Google Patents

Abstract

PURPOSE:To obtain the subject composition low in toxicity. improved in recoating adhesivity and storage stability. and useful as a top coating by compounding a plurality of specific vinylic polymers. CONSTITUTION:This composition comprises (A) 10-99 pts.wt. of a vinylic polymer whose main chain comprises a vinylic polymer chain and which has at least a hydrolyzable silyl group of the formula [R<1>, R<2> are H or either one of monovalent hydrocarbons consisting of a 1-10C alkyl, an aryl and an aralkyl; (a) is 0, 1, 2] in the molecule, and (B) 1-90 pts.wt. of a vinylic polymer whose main chain comprises substantially a vinylic polymer and which has at least a sulfonyl group in the molecule on the average or a vinylic polymer in which a part or all of the sulfonyl groups are blocked with a nitrogen-containing compound. The OH group value of the component A is preferably 5-250mg/KOH.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition for paints, and more particularly to a curable composition for paints having low toxicity and improved recoat adhesion and storage stability, mainly for top coats, In particular, it relates to a curable composition which is useful as a top coating material for automobiles.

[0002]

2. Description of the Related Art Resins for coating materials that have been conventionally used for automobiles, building exteriors, industrial machinery, steel furniture, plastics, etc. are mainly melamine resins such as alkyd melamine and acrylic melamine. Alternatively, it was a two-component urethane resin.

The melamine resin has problems that harmful formalin is generated at the time of curing and that the cured coating film is inferior in acid resistance, so that it is attacked by acid rain.

In addition, the toxicity of the isocyanate compound used in the two-component urethane resin has been a problem.

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

A characteristic of the vinyl polymer having a hydrolyzable silyl group is that the silyl group is hydrolyzed by moisture in the air, and is cured through a condensation reaction. Also,
Melamine resins such as acrylic melamine and alkyd melamine, because they form and cure stable siloxane bonds,
It is superior in chemical resistance and weather resistance as compared with the case of using a two-component urethane resin.

However, this vinyl polymer having a hydrolyzable silyl group is used as a coating material (for example, a top coating material for automobiles).
When used as, there were the following problems.

The storage stability was not sufficient. In particular, a tin compound such as di-n-butyltin (IV) dilaurate, a sulfonic acid such as p-toluenesulfonic acid, or an acidic phosphoric acid ester such as di-2-ethylhexyl phosphate was added as a curing catalyst. In this case, since the activity at room temperature was high, the one-liquid storage stability was insufficient.

When a vinyl-based carboxylic acid such as acrylic acid is copolymerized, the one-pack stability described above is improved to some extent, but the recoat adhesion is not satisfactory.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object thereof is excellent weather resistance such as acid resistance originally possessed by a hydrolyzable silyl group-containing vinyl polymer. In addition to the above, another object of the present invention is to provide a curable composition for coatings, which has excellent recoat adhesion and storage stability.

[0011]

Means and Actions for Solving the Problems The curable composition for coating materials of the present invention comprises (A) a main chain consisting essentially of a vinyl polymer chain, and a general formula at the main chain terminal and / or side chain. (1):

[Chemical 2] (In the formula, R ¹ and R ² are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an araryl group, and a represents 0, 1 or 2. When each of R ¹ and R ² is 2 or more, they may be the same group or different groups.) In one molecule, at least a hydrolyzable silyl group represented by 10 to 99 parts by weight of a vinyl polymer having one (hereinafter, also referred to as "hydrolyzable silyl group-containing vinyl polymer" or simply "(A) component") (hereinafter referred to as "part"), and (B) The main chain consists essentially of vinyl polymer chains, and the sulfonic acid groups are at least 1 on average in one molecule.
Individual vinyl polymer, or a vinyl polymer obtained by reacting a part or all of the sulfonic acid group with a nitrogen-containing compound to block (hereinafter, referred to as "sulfonic acid group-containing vinyl polymer" or simply "(B)". Also referred to as "ingredient".) 1
90 parts are mixed.

(A) Hydrolyzable silyl group-containing vinyl-based polymer
Coupling In the hydrolyzable silyl group-containing vinyl polymer of the component (A) in the present invention, the main chain is substantially composed of a vinyl polymer chain, and the main chain terminal and / or side chain has the above-mentioned general formula ( It is a polymer having at least one, preferably 2 to 10 hydrolyzable silyl groups represented by 1) in one molecule.

Since the hydrolyzable silyl group-containing vinyl polymer is substantially composed of a vinyl polymer chain, the cured product has excellent weather resistance, chemical resistance and the like, and by changing the copolymer composition, A wide range of resin designs from soft to hard are possible. The vinyl polymer is usually about 50% by weight (hereinafter, simply referred to as "%") of the units constituting the main chain, preferably about 60% or more, and more preferably 8%.
About 0% or more is composed of vinyl monomer units. Therefore, the vinyl polymer as the component (A) may partially contain a urethane bond, a siloxane bond or the like in the main chain or side chain.

Examples of the hydrolyzable silyl group include the groups represented by the above general formula (1).

When the carbon number of R ¹ and R ² exceeds 10, the hydrolytic reactivity of the hydrolyzable silyl group is lowered.
Specific examples of R ¹ include, for example, methyl group, ethyl group, n
-Propyl group, isopropyl group, n-butyl group, isobutyl group and the like.

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

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

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

If the molecular weight per hydrolyzable silyl group of the polymer of the component (A) is too large, the formation of siloxane bonds will be small, and the effects of the present invention will not be sufficiently exhibited. On the contrary, if it is too small, the internal stress increases. Therefore, 300 to 5,000 is preferable, 350 to 2,500
0 is more preferable.

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

The vinyl-based monomer is not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth). ) Acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoro Ethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, unsaturated polycarboxylic acid (maleic acid, fumaric acid, itaconic acid, etc.) and 1 to 20 carbon atoms
Unsaturated polycarboxylic acid esters such as diesters or half esters with linear or branched alcohols; aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, sodium styrenesulfonate; vinyl acetate, Vinyl esters and allyl compounds such as vinyl diallyl phthalate propionate; vinyl compounds containing nitrile groups such as (meth) acrylonitrile; vinyl compounds containing epoxy groups such as glycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, dimethylaminoethyl ( Vinyl compounds containing a basic nitrogen atom such as (meth) acrylate, diethylaminoethyl (meth) acrylate, vinyl pyridine, aminoethyl vinyl ether; (meth) acrylamide,
Itaconic acid diamide, α-ethyl (meth) acrylamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloyl Amido group-containing vinyl compounds such as morpholine; vinyl methyl ether, vinyl chloride, vinylidene chloride, chloroprene,
Propylene, butadiene, isoprene, maleimide, N
-Other vinyl compounds such as vinyl imidazole may be mentioned.

Of these vinyl-based monomers, the use of a hydroxyl group-containing monomer is particularly preferable because the curability can be further enhanced. The copolymerization amount of the hydroxyl group-containing monomer is not particularly limited, but the hydroxyl value in the polymer of the component (A) is 5 to 250 mgKOH / g, preferably 10 to 200 mgKOH / g, more preferably 15 to
It is set to be 180 mg / KOHg. In the polymer of the component (A), when the hydroxyl value is less than 5 mgKOH / g, the curability is not always sufficient, while the hydroxyl value is 2
When it exceeds 50 mgKOH / g, acid resistance and water resistance are deteriorated.

The hydroxyl group-containing monomer is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2
-Hydroxybutyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, 4-hydroxystyrene vinyltoluene, Aronix 5700 manufactured by Toa Gosei Chemical Industry Co., Ltd.,
4-hydroxystyrene, HE-10, HE-20, HP-1 and HP-20 manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.
(All of the above are acrylic acid ester oligomers having a hydroxyl group at the terminal), Bremmer PP manufactured by NOF CORPORATION
Series (polypropylene glycol methacrylate)
Bremmer PE series (polyethylene glycol monomethacrylate), Bremmer PEP series (polyethylene glycol polypropylene glycol methacrylate), Bremmer AP-100 (polypropylene glycol monoacrylate), Bremmer AE-350
(Polyethylene glycol monoacrylate), Bremmer NKH-5050 (Polypropylene glycol polytrimethylene monoacrylate) and Bremmer GL
Examples thereof include M (glycerol monomethacrylate), an ε-caprolactone-modified hydroxyalkylvinyl-based copolymerizable compound obtained by the reaction of a hydroxyl group-containing vinyl compound and ε-caprolactone. Above all, the use of 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate is preferable because it can impart excellent acid resistance and water resistance to the coating film.

A typical example of the ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound is, for example, the general formula (2):

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

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

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

[0027]

[Chemical 4]

[0028]

[Chemical 5] And the like, and also includes (meth) acrylate having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond. These alkoxysilyl group-containing vinyl-based copolymerizable compounds may be used alone,
You may use 2 or more types together.

As the method for producing the polymer as the component (A), generally, the above-mentioned hydrolyzable silyl group-containing monomer and a vinyl monomer are copolymerized, for example, JP-A-54-3639.
5, JP-A-57-36109, JP-A-57-559.
No. 53, No. 58-157810 and the like are exemplified, and it is easy to handle when produced by a solution polymerization method using an azo radical initiator such as azobisisobutyronitrile. From the point of, it is preferable.

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

[Chemical 6] The molecular weight may be adjusted using a chain transfer agent such as. In particular, if a chain transfer agent having a hydrolyzable silyl group in the molecule, such as γ-mercaptopropyltrimethoxysilane, is used, the hydrolyzable silyl group can be introduced at the end of the vinyl copolymer produced. .

The polymerization solvent used for the solution polymerization is
Hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetic acid esters (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, n-butanol, etc.), ethers (ethyl cellosolve, butyl cellosolve) , Cellosolve acetate, etc., ketones (methyl ethyl ketone,
Examples thereof include non-reactive solvents such as ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, and acetone), and there is no particular limitation as long as they are such solvents.

These polymerization solvents may be used alone,
Two or more kinds may be used in combination, but particularly when a vinyl-based copolymer (A) containing both a hydrolyzable silyl group and an alcoholic hydroxyl group is polymerized, all of the vinyl-based copolymer is composed. When the amount of the copolymerizable compound is 100 parts and the amount of the alcoholic solvent such as methanol and butanol in the solvent composition is less than 1 part, gelation may occur during the polymerization. Therefore, it is preferable that the solvent composition used during the polymerization of the vinyl copolymer (A) containing both a hydrolyzable silyl group and an alcoholic hydroxyl group contains an alcoholic solvent, It is preferable to use 1 to 30 parts when the total amount of the copolymerizable compounds constituting the vinyl-based copolymer is 100 parts.

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. It may contain a segment derived from a sex compound.

(B) Sulfonic Acid Group-Containing Vinyl Polymer (B) The polymer of the component (B) has a main chain consisting essentially of a vinyl polymer chain, and has at least 1 sulfonic acid group on average in one molecule. Or a vinyl polymer obtained by reacting a part or all of the sulfonic acid group with a nitrogen-containing compound to block the vinyl polymer.

The polymer as the component (B) is, for example, a sulfonic acid group-containing vinyl monomer, or a vinyl monomer in which a part or all of the sulfonic acid group is reacted with a nitrogen-containing compound to block it, and other vinyl. It is obtained by copolymerizing with a system monomer.

Examples of the vinyl monomer containing a sulfonic acid group in this case include 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl methacrylate, styrenesulfonic acid, vinylsulfonic acid, and (meth).
Examples thereof include acrylic sulfonic acid. Among these monomers, 2-acrylamido-2-methylpropanesulfonic acid or 2-sulfoethyl methacrylate is preferable from the viewpoint of easy handling.

Examples of the above-mentioned nitrogen-containing compounds include aliphatic chain amines, aliphatic cyclic amines, aromatic amines and the like. Among the above amines, primary or secondary amines having at least one hydroxyl group in one molecule and morpholine are preferable from the viewpoint of curability and storage stability of one liquid.

Specific examples of the amine include 2
-(Methylamino) ethanol, diisopropanolamine, 2-amino-2-methyl-1-propanol, 3
-Amino-1-propanol, 1-amino-2-propanol, 6-amino-1-hexanol, 4-amino-
1-butanol, 2-amino-2-methyl-1-propanol, morpholine and the like can be mentioned.

The ratio of the amine to the sulfonic acid is such that the amine is 0.5 to 3. per 1 equivalent of the sulfonic acid group.
It is preferably 0 equivalent, more preferably 0.75 to 2.5 equivalents, still more preferably 0.9 to 2.0 equivalents.

When the equivalent of amine to 1 equivalent of sulfonic acid group is less than 0.5, the storage stability of one liquid and the appearance of the coating film are deteriorated, and when it exceeds 3.0, the coating film is colored. And the water resistance tends to decrease.

As the other vinyl-based monomer,
For example, methyl (meth) acrylate, ethyl (meth)
Acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate,
3,3,5-Trimethylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth)
Acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, unsaturated polycarboxylic acid (maleic acid, fumaric acid, itaconic acid, etc.) and carbon number 1 ~ 20 unsaturated polycarboxylic acid esters such as diesters or half-esters with linear or branched alcohols; aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, sodium styrenesulfonate; acetic acid Vinyl, vinyl ester and allyl compounds such as vinyldiallyl phthalate propionate; vinyl compounds containing nitrile groups such as (meth) acrylonitrile; vinyl compounds containing epoxy groups such as glycidyl (meth) acrylate; Basic nitrogen atom-containing vinyl compounds such as noethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, vinylpyridine and aminoethyl vinyl ether; (meth) acrylamide, itaconic acid diamide, α-ethyl ( (Meth) acrylamide, crotonamide, maleic acid diamide, fumaric acid diamide,
N-vinylpyrrolidone, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-
Amide group-containing vinyl compounds such as methyl acrylamide and acryloylmorpholine; other vinyl compounds such as vinyl methyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, maleimide and N-vinyl imidazole.

Of these vinyl-based monomers, the use of a hydroxyl group-containing monomer is particularly preferable because the curability can be further increased. The copolymerization amount of the hydroxyl group-containing monomer is not particularly limited, but the hydroxyl value of the polymer as the component (B) is 5 to 250 mgKOH / g, preferably 10
~ 200 mgKOH / g, more preferably 15-18
It is preferable to set it to be 0 mgKOH / g.

The hydroxyl value of the polymer of component (B) is 5 mgK.
When it is less than OH / g, the curability is not always sufficient, while when the hydroxyl value exceeds 250 mgKOH / g, acid resistance and water resistance are deteriorated.

The hydroxyl group-containing monomer is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2
-Hydroxybutyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, 4-hydroxystyrene vinyltoluene, Aronix 5700 manufactured by Toa Gosei Chemical Industry Co., Ltd.,
4-hydroxystyrene, HE-10, HE-20, HP-1 and HP-20 manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.
(All of the above are acrylic acid ester oligomers having a hydroxyl group at the terminal), Bremmer PP manufactured by NOF CORPORATION
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),
Blemmer NKH-5050 (polypropylene glycol polytrimethylene monoacrylate) and Blemmer GLM (glycerol monomethacrylate), ε-caprolactone-modified hydroxyalkyl vinyl-based copolymerizable compound obtained by reaction of hydroxyl group-containing vinyl compound and ε-caprolactone, etc. Is mentioned. 2-
The use of hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate is preferable because excellent acid resistance and water resistance can be imparted to the coating film.

A typical example of the ε-caprolactone-modified hydroxyalkylvinyl copolymerizable compound is, for example, the general formula (2):

[Chemical 7] (In the formula, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more) Placel FA-1 (R = H, n =, manufactured by Daicel Chemical Industries, Ltd.)
1), Placcel FA-4 (R = H, n = 4),
Placcel FM-1 (R = CH ₃ , n = 1), P
laccel FM-4 (R = CH ₃ , n = 4), UC
C Corp. TONE M-100 (R = H , n = 2) and _{TONE M-201 (R = CH} 3, n = 1) , and the like.

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

Further, the curability can be improved by copolymerizing an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid.

Further, in this case, a part or all of the carboxylic acid is blocked by reacting with a silyl group such as a trimethylsilyl group or a dimethyl tert-butylsilyl group, or ethyl vinyl ether or 3,4-dihydro-2H. It may be a latent carboxyl group by blocking by reacting with a vinyl ether such as pyran.

In this case, the acid value of the carboxylic acid is 150 mgKOH / in the vinyl polymer as the component (B).
It is preferably g or less, more preferably 100 mgKOH / g or less, and further preferably 60 mgKOH / g or less. This acid value is 150 mg
If it exceeds KOH / g, the water resistance decreases.

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

As a method for producing the polymer as the component (B), generally, the above-mentioned sulfonic acid group-containing monomer and a vinyl-based monomer are copolymerized, for example, as disclosed in JP-A-2-289642 and JP-A-3-47854. Although the method shown is exemplified, it is preferable to manufacture by a solution polymerization method using an azo radical initiator such as azobisisobutyronitrile from the viewpoint of easy handling.

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

[Chemical 8] The molecular weight may be adjusted using a chain transfer agent such as. In particular, if a chain transfer agent having a hydrolyzable silyl group in the molecule, such as γ-mercaptopropyltrimethoxysilane, is used, the hydrolyzable silyl group can be introduced at the end of the vinyl copolymer produced. .

The polymerization solvent used for the solution polymerization is
Hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetic acid esters (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, n-butanol, etc.), ethers (ethyl cellosolve, butyl cellosolve) , Cellosolve acetate, etc., ketones (methyl ethyl ketone,
Examples thereof include non-reactive solvents such as ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, and acetone), and there is no particular limitation as long as they are such solvents. These polymerization solvents may be used alone or in combination of two or more kinds.

A curing catalyst may be added to the present invention. Examples of the curing catalyst include organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, tin octylate; phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monobutyl phosphate. Octyl phosphate, monobutyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate,
Phosphoric acid or phosphoric acid ester such as didecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acryl glycidyl ether, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane,

[Chemical 9] Yuka Shell Epoxy Co., Ltd. Cardura E, Yuka Shell Epoxy Co., Ltd. Epicoat 828, Epicoat 1
Addition reaction products of epoxy compounds such as 001 with phosphoric acid and / or monophosphoric acid ester; organic titanate compounds; organoaluminum compounds; maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, succinic acid, phthalate Acids, trimellitic acid, pyromellitic acid and their acid anhydrides; acidic compounds such as dodecylbenzelsulfonic acid and paratoluenesulfonic acid and their reaction products with amines (for example, N manufactured by KING INDUSTRIES).
ACURE 5225, NACURE 5543, NACU
RE5925); amines such as hexylamine, di-2-ethylhexylamine, N, N-dimethyldodecylamine, dodecylamine, DABCO, DBU, morpholine, diisopropanolamine; reaction products of these amines with acidic phosphate And alkaline compounds such as sodium hydroxide and potassium hydroxide. Such curing catalysts may be used alone or in combination of two or more kinds.

Among these curing catalysts, acidic compounds such as dodecylbenzene sulfonic acid and paratoluene sulfonic acid, and reaction products of these with amines are preferable from the viewpoint of storage stability.

The amount of the curing catalyst added is less than 10 parts, preferably less than 5 parts, and particularly preferably less than 2 parts, based on 100 parts of the total of the components (A) and (B).

The ratio of the components (A) and (B) used is
The component (A) is 10 to 99 parts, preferably 20 to 95 parts, and the component (B) is 90 to 1 part, preferably 80 to 5 parts. When the ratio of the component (A) and the component (B) is within the above range, the curability, storage stability, recoat adhesion, water resistance, etc. are good and the balance is excellent, which is preferable.

In the composition of the present invention, organopolysiloxane silanols, tetraalkoxysilanes, alkyltrialkoxysilanes, partial hydrolysates thereof, amino resins such as melamine and the like are added as the component (A) and It may be added in an amount of preferably 50 parts or less, more preferably 30 parts or less, relative to 100 parts of the total amount of the component (B). If more than 50 parts of organopolysiloxane silanol is added, the abrasion resistance is rather lowered, and if more than 50 parts of tetraalkoxysilane, alkyltrialkoxysilane or its partial hydrolyzate is added, the compatibility is lowered, Internal stress increases. Also, 50 amino resins such as melamine
If more than 50 parts is added, the acid resistance is rather lowered, and if more than 50 parts of polyol is added, the water resistance is decreased.

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

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

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 usually 70 parts or less, preferably 50 parts, relative to 100 parts of the total amount of the components (A) and (B).
It is not more than 20 parts, and more preferably not more than 20 parts. When the amount of the dehydrating agent added exceeds 70 parts, the stabilizing effect of the alkoxysilyl group is almost unchanged, and it becomes difficult to form a high solid.

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

The amount of the alcohol used is not particularly limited, but is usually 70 parts or less, preferably 50 parts or less, relative to 100 parts of the total amount of the components (A) and (B), preferably 20 parts or less. It is more preferable that the amount is not more than part.

When a solvent alone is used without using a dehydrating agent, it is usually 0.5 to 70 parts, preferably 1 to 50 parts, more preferably 2 to 20 parts.
When the amount of the alcohol solvent is less than 0.5 part, there is almost no effect of stabilizing the alkoxysilyl group. If it exceeds 70 parts, it becomes difficult to obtain a high solid.

When the composition of the present invention is used as a top coat, the weather resistance can be further improved by blending an ultraviolet absorber and a light stabilizer, particularly by using them together.

As the above-mentioned UV absorber, conventionally known ones can be widely used. For example, benzophenone-based, triazole-based, phenylsalicylate-based, diphenylacrylate-based, acetophenone-based UV absorbers are preferable.

As the above-mentioned light stabilizer, those publicly known can be widely used, and for example, bis (2,2,6-trimethyl-
4-piperidyl) sebacate, bis (1, 2, 2, 6,
6-pentamethyl-4-piperidyl) sebacate, 2-
Bis (1,2,2,2,3-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate
6,6-pentamethyl-4-piperidyl), tetrakis (2,2,6,6-tetramethyl-4-piperidyl)-
1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate and the like can be mentioned. These may be used alone,
You may use 2 or more types together.

The amount of the ultraviolet absorber blended is usually 0.1 to 10 parts, preferably 1 to 5 parts, relative to 100 parts of the solid content of the composition. Moreover, the compounding quantity of a light stabilizer is 0.1-10 parts normally with respect to 100 parts of solid content of a composition, Preferably it is 1-5 parts.

When the composition of the present invention is used as a top coat clear paint, additives such as diluents, cissing inhibitors, leveling agents, etc., depending on the application; nitrocellulose, cellulose acetate butyrate, and other fibrin-based 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 concentration of 50 to 70%, and is applied to a substrate by a method such as spray coating, brush coating, roll coating or dip coating. After that, it is cured by heating at about 80 to 160 ° C. to be a cured coating film excellent in chemical resistance such as acid resistance, weather resistance and scratch resistance.

The composition of the present invention is useful for coating automobiles, building exteriors, industrial machines, steel furniture, plastics and the like, and is extremely useful as a top coat, especially as a top coat for automobiles.

[0072]

EFFECTS OF THE INVENTION The curable composition for coating composition of the present invention has excellent weather resistance such as acid resistance originally possessed by the hydrolyzable silyl group-containing vinyl polymer, excellent recoat adhesion and storage stability. Have.

[0073]

EXAMPLES Hereinafter, the curable composition for coating materials of the present invention will be described more specifically based on examples. However, the invention is not limited to these examples.

Example of Synthesis of Component (A) [Table 1] Under a nitrogen atmosphere, the mixed solution (1a) was added dropwise at a constant rate to the mixture (2a) heated to 105 ° C. over 5 hours.
Next, the mixed solution (3a) was added dropwise thereto at a constant rate over 1 hour. Then, the mixture was continuously stirred at 105 ° C. for 2 hours and then cooled to room temperature. Finally, the mixed solution (4a) was added and stirred. The solid content concentration of the obtained solution, the number average molecular weight of the copolymer measured by gel permeation chromatography (GPC), and the hydroxyl value are shown in [Table 1].

[0075]

[Table 1]

Example of Synthesis of Component (B) [Table 2] Under a nitrogen atmosphere, the mixed solution (1b) was added dropwise at a constant rate to the mixture (2b) heated to 80 ° C. over 5 hours.
Next, the mixed solution (3b) was added dropwise thereto at a constant rate over 3 hours. Then, the mixture was continuously stirred at 80 ° C. for 2 hours and then cooled to room temperature. The solid content concentration of the obtained solution,
The number average molecular weights of the copolymer measured by GPC were 63% and 5,000, respectively. The hydroxyl value and the acid value are as shown in [Table 2].

[0077]

[Table 2] Sulfonic acid solution I and sulfonic acid solution I in the above [Table 2]
See Table 3 for I and sulfonic acid solution III.

[0078]

[Table 3]

Examples 1-5 and Comparative Examples 1-2 The polymer (A) component obtained in [Table 1] and the polymer (B) component obtained in [Table 2] are shown in [Table 4]. It was compounded in the ratio shown.
A leveling agent (L-1984-50 manufactured by Kusumoto Kasei Co., Ltd.) was added to the total resin solid content of each Example or Comparative Example.
4% was added. This mixture was diluted with Solvesso 100 and adjusted to a viscosity of about 20 to 25 seconds with a Ford cup to give a clear coating for a top coat.

A coated plate obtained by coating a degreased and phosphorylated mild steel plate with an epoxyamide-based cationic electrodeposition primer for automobiles and an intermediate coat surfacer was used as a test piece, and a commercially available acrylic melamine resin coating (silver metallic base coat) was used. ) Was given. next,
After applying the clear paint for top coat wet-on-wet and setting for 20 minutes,
Baked at 30 ° C for 30 minutes.

The dry film thickness of the base coat is about 15 μm,
The top coat clear was about 50 μm.

The obtained coating film was evaluated by the following methods.
The results are also shown in [Table 4].

1. Pencil hardness A test was conducted according to JIS K5400 for evaluation.

2. Recoat Adhesion The obtained coated plate is again subjected to the above base coat in the same manner as the first time, and then each clear paint is applied wet-on-wet, and after setting for 20 minutes, 120 ° C.
Baked for 30 minutes. The adhesion of the coated plate is JIS K
According to the 5400 cross-cutting method (2 mm x 2 mm x 25),
evaluated.

3. 100g of clear paint for each top coat in storage stable coating state
It was taken in a 30 cc glass bottle, sealed, and stored at 40 ° C. for 14 days. The viscosity was measured with a Ford cup at 23 ° C., and the measured value was divided by the initial viscosity to evaluate the storage stability. A low viscosity change rate indicates excellent storage stability.

[0086]

[Table 4]

As is clear from Table 4, the composition of the present invention was found to be excellent in recoat adhesion and storage stability.

Claims (6)

[Claims] 1. A main chain of (A) consists essentially of a vinyl polymer chain, and the main chain ends and / or side chains are represented by the general formula (1): (In the formula, R ¹ and R ² are a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group and an araryl group, and a is 0, 1 or 2. .) 10 to 99 parts by weight of a vinyl polymer having at least one hydrolyzable silyl group in one molecule, and (B) the main chain consisting essentially of the vinyl polymer chain. 1 to 90 parts by weight of a vinyl polymer having an average of at least one group in one molecule, or a vinyl polymer obtained by reacting a part or all of the sulfonic acid group with a nitrogen-containing compound to block it is blended. A curable composition for coating composition. 2. The hydroxyl value of the component (A) is 5 to 250 m.
The curable composition for coating materials according to claim 1, which is gKOH / g. 3. The component (B) is 2-acrylamide-
A compound obtained by copolymerizing a mixed monomer containing 2-methylpropanesulfonic acid and / or 2-sulfoethyl methacrylate as a sulfonic acid group-containing vinyl monomer, and having at least one hydroxyl group on average. Item 3. A curable composition for paint according to Item 1 or 2. 4. The hydroxyl value of the component (B) is 5 to 250 m.
The curable composition for coating according to any one of claims 1 to 3, which is gKOH / g. 5. The component (B) is a vinyl polymer having a carboxyl group or a vinyl polymer obtained by reacting a part or all of the carboxyl group to block the acid value of 150 mgKOH. / G or less, The curable composition for coating materials according to any one of claims 1 to 4. 6. The nitrogen-containing compound is morpholine, or the average number of hydroxyl groups in one molecule is at least 1.
It is a primary or secondary amine compound having one unit.
A curable composition for coating according to any one of items 1 to 5.