JPH05331251A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain a curable composition having low-temperature curing properties, excellent storage stability, providing a coating film having high luster, by dispersing fine particles of a polymer in a solution of a specific acrylic polymer in a volatile organic solvent and further mixing a curing catalyst therein. CONSTITUTION:The composition comprises (A) an acrylic polymer composed of an alkoxysilane group-containing vinyl compound of the formula (A is COO or phenylene; R1 is H or methyl; R2 is 1-6C bifunctional aliphatic saturated hydrocarbon; R3 and R4 is phenyl, 1-6C alkyl, etc.; R5 is 1-10C alkyl; (n) is l-100) (preferably gamma-acryloyloxypropyltrimethoxysilane) as an essential monomer component, (B) an organic liquid diluent (e.g. butyl acetate) dissolving the component A, (C) fine particles of a polymer stably dispersed in the solution of the component A in the component B without being dissolved and (D) a curing catalyst (e.g. p-toluenesulfonic acid). The component C, for example, is obtained by subjecting a radical-polymerizable unsaturated monomer such as methyl acrylate to emulsion polymerization in an aqueous medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition having a low temperature curability, a good storage stability, a large sagging limit film thickness and a high gloss coating film.

[0002]

2. Description of the Related Art Conventionally, room temperature to 100 ° C.
As a composition capable of being crosslinked and cured at a relatively low temperature, there is known a composition in which a curing catalyst such as a tin compound is mixed with an acrylic resin containing an alkoxysilane group (JP-A-58-13).
6606 publication).

However, although the above-mentioned conventional compositions are excellent in low-temperature curability, chemical resistance, water resistance, etc., they have the drawback that the coating film mechanical properties and coating storage stability are not always sufficient. .. That is, when high mechanical properties such as impact resistance and bending resistance are required, the amount of the curing catalyst,
There is a limit only by adjusting the type, content of alkoxysilane group, molecular weight of acrylic resin, etc., and therefore there are drawbacks such as limited applications and insufficient paint storage stability and weather resistance. Further, the above-mentioned composition has a drawback in that, when a vertical surface is coated, a phenomenon in which the coating material drips (generally called sag) tends to occur at a thick film thickness. Due to this lack of suitability for thick film coating, multiple coatings are required to obtain a predetermined film thickness, and the finish of the coated surface is poor, which is a major obstacle to practical use. In order to obtain suitability for thick film coating, polyamide resin type, organic bentonite type,
When the anti-sagging agent such as polyethylene oxide is blended, there is a problem that the gloss of the obtained coating film is significantly reduced.

Therefore, the inventors of the present invention can form a coating film having low temperature curability, good storage stability, and excellent coating surface condition, chemical resistance, water resistance, weather resistance and mechanical properties. As a result of earnest research to obtain a curable composition having a large sag limit film thickness and capable of forming a highly glossy coating film, the present invention has been accomplished.

That is, the present invention provides (a) general formula [1]

[0006]

[Chemical 2]

[In the formula, A represents -COO- or a phenylene group. R ₁ is a hydrogen atom or a methyl group, R ₂ is a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, R ₃ and R ₄
Are the same or different and each represents a phenyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, and R ₅ is an alkyl group having 1 to 10 carbon atoms. n is 1 to 10
Indicates an integer of 0. ] An acrylic polymer containing an alkoxysilane group-containing vinyl compound represented by the following as an essential monomer component:

(B) a volatile organic liquid diluent that dissolves the acrylic polymer (a), (c) a stable dispersion without dissolving in the solution of the acrylic polymer (a) in the diluent (b) The present invention provides a curable composition characterized by containing fine polymer particles and (d) a curing catalyst.

In the present invention, the acrylic polymer as the component (a) contains the specific alkoxysilane group-containing vinyl compound represented by the above general formula [1] as an essential monomer component. In the above general formula [1], the divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms represented by R ₂ is a linear or branched alkylene group such as methylene, ethylene, propylene, 1,2- Butylene, 1,3
-Butylene, 2,3-butylene, tetramethylene, ethylethylene, pentamethylene, hexamethylene groups and the like can be mentioned. 1 to ₃ carbon atoms represented by R ₃ and R ₄
Examples of the alkyl group of 6 include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl,
n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-
Hexyl, isohexyl groups and the like can be mentioned, and R ₅
As the alkyl group having 1 to 10 carbon atoms represented by, in addition to the above alkyl group, n-heptyl, 1-methylpentyl, 2-methylhexyl, n-octyl, n-nonyl,
Examples thereof include n-decyl.

The alkoxy group having 1 to 10 carbon atoms represented by R ₃ and R ₄ is a linear or branched alkoxy group such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec. -Butoxy, tert-butoxy, n-pentoxy, isopentoxy, n-hexyloxy, isohexyloxy, n-octyloxy and the like can be mentioned. Further, in the general formula [1], n is an integer of 1 to 100, but n is 2
In the above case, R ₃ and R ₄ may be the same or different.

In the present invention, the compound represented by the general formula [1] wherein A is —COO— is, for example, γ- (meth) acryloyloxyethyltrimethoxysilane, γ- (meth) acryloyloxypropyl. Trimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropyltripropoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ
-(Meth) acryloyloxypropylmethyldiethoxysilane, γ- (meth) acryloyloxypropylmethyldipropoxysilane, γ- (meth) acryloyloxybutylphenyldimethoxysilane, γ- (meth) acryloyloxybutylphenyldiethoxysilane, γ
-(Meth) acryloyloxybutylphenyldipropoxysilane, γ- (meth) acryloyloxypropyldimethylmethoxysilane, γ- (meth) acryloyloxypropyldimethylethoxysilane, γ- (meth) acryloyloxypropylphenylmethylmethoxysilane, γ -(Meth) acryloyloxypropylphenylmethylethoxysilane,

[0012]

[Chemical 3]

And the like.

Among the compounds represented by the general formula [1], those in which A is a phenylene group include, for example:

[0015]

[Chemical 4]

And the like.

Among these compounds represented by the general formula [1], γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrin-butoxysilane and γ-acryloyl are particularly preferable. Oxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyl n-butoxysilane and the like are preferable.

In the present invention, the acrylic polymer as the component (a) contains at least one of the alkoxysilane group-containing vinyl compounds represented by the general formula [1] as an essential monomer component and, if necessary, other monomer. It is a polymer obtained by copolymerizing a monomer. The proportion of the essential monomer used can be selected from a wide range, but it is usually 1% by weight or more, preferably about 5 to 30% by weight in the monomers used.

The other polymerizable monomer used as necessary in the polymer can be appropriately selected depending on the performance required for the coating film. Other monomers that can be preferably used include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tertbutyl (meth) acrylate. ,
Alkyl or cyclo of (meth) acrylic acid such as 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate and stearyl (meth) acrylate. Alkyl ester; Alkoxyalkyl ester of (meth) acrylic acid such as methoxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxybutyl (meth) acrylate; Aromatic alcohol and (meth) acrylic such as benzyl (meth) acrylate Ester with acid; adduct of hydroxyalkyl ester of glycidyl (meth) acrylate or (meth) acrylic acid with monocarboxylic acid compound such as capric acid, lauric acid, linoleic acid, oleic acid, ( A) Addition product of acrylic acid and a monoepoxy compound such as "CARDURA E10" (manufactured by Shell Chemical Co.); vinyl fragrance such as styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, p-tert-butylstyrene. Group compounds; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid, crotonic acid, maleic acid, Α, β-ethylenically unsaturated carboxylic acids such as maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid and citraconic acid; glycidyl group-containing compounds such as glycidyl (meth) acrylate, vinyl glycidyl ether and allyl glycidyl ether; (Meth) acrylamide, N, N-dime Le (meth) acrylamide, N- alkoxymethyl (meth)
Carboxylic acid amide compounds such as acrylamide, diacetone acrylamide, N-methylol (meth) acrylamide; P-styrene sulfonamide, N-methyl-P
-Sulfonamide group-containing compounds such as styrenesulfonamide and N, N-dimethyl-P-styrenesulfonamide; "biscoat 8F", "biscoat 8FM", "biscoat 3F", "biscoat 3FM" (all are Osaka Organic Chemicals Co., Ltd., having a fluorine atom in the side chain (meta)
Acrylates), perfluorocyclohexyl (meth) acrylate, fluorine atom-containing compounds such as perfluorocyclohexyl ethylene, and the like.

The acrylic polymer which is the component (a) preferably contains 30% by weight or more of the total amount of acrylic acid or methacrylic acid ester among the monomer components from the viewpoint of weather resistance and the like. It is more preferable that the content is 50 wt% or more.

The polymerization for producing the acrylic polymer as the component (a) is usually carried out using a radical polymerization initiator. Examples of usable radical initiators include 2,
Azo initiators such as 2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, lauroyl peroxide, tert-butyl peroxyoctoate, tert- Examples thereof include peroxide-based initiators such as butylperoxy-2-ethylhexanoate, and these initiators are generally used in an amount of about 0.2 to 10 parts by weight, preferably 100 parts by weight of the monomers used for the polymerization. It can be used within the range of 0.5 to 5 parts by weight. It is suitable to use a temperature in the range of about 60 to 160 ° C. during the polymerization, and the reaction is usually completed in about 1 to 15 hours.

The molecular weight of the acrylic polymer as the component (a) is usually about 5,000 to 100,0 in terms of weight average molecular weight.
00 (number average molecular weight of about 1,000 to 60,000)
Degree), preferably about 5,000-5 by weight average molecular weight
It is in the range of about 10,000.

The diluent, which is the component (B) in the composition of the present invention, dissolves the film-forming binder resin (A), but does not dissolve the polymer fine particles (C) described later, and is a volatile organic compound that stably disperses the polymer fine particles (C). Included are any liquids that are liquid diluents and are conventionally used as solvents in coating compositions. Specifically, for example, aromatic hydrocarbons such as toluene and xylene; petroleum fractions in various boiling ranges containing a substantial proportion of aromatics; butyl acetate, ethylene glycol diacetate and 2-ethoxyethyl acetate. Mention may be made of esters; ketones such as acetone and methyl isobutyl ketone; alcohols such as butyl alcohol and the like or mixtures thereof.

The polymer fine particles which are the component (c) in the composition of the present invention are the acrylic polymer (a) in the diluent (b).
It is necessary that it is not dissolved in the solution of 1 and is stably dispersed. The polymer particles (c) may be polymer particles obtained as an emulsion by emulsion-polymerizing a radical-polymerizable unsaturated monomer in an aqueous medium, or in an organic liquid in the presence of a dispersion stabilizer resin. Polymer fine particles obtained as a non-aqueous dispersion by polymerizing a radical-polymerizable unsaturated monomer may be used.

When emulsion polymerization is carried out in an aqueous medium to produce fine polymer particles, an emulsifier or a polymer dispersion dissolved in an aqueous medium in water or a medium containing water as a main component and a hydrophilic solvent is mixed. The radically polymerizable unsaturated monomer may be emulsion polymerized in the presence of a stabilizer. As the emulsifier, any of known anionic, cationic and nonionic emulsifiers used in emulsion polymerization can be used. From the viewpoint of stability of the polymer particles obtained, it is preferable that the emulsifier has a relatively low-reactive group such as an allyl group and is gradually incorporated into the polymer during the polymerization. Examples of the polymer dispersion stabilizer include a neutralized resin of maleated polybutadiene, polyvinyl alcohol, a water-soluble fibrin derivative, a water-soluble acrylic resin and a water-soluble alkyd resin.

Further, the radically polymerizable unsaturated monomer can be appropriately selected according to the performance required for the coating film. As a monomer component which can be preferably used, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tertbutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl Alkyl or cycloalkyl ester of (meth) acrylic acid such as (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate; methoxybutyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxybutyl (meth) acrylate An alkoxyalkyl ester of (meth) acrylic acid such as; an ester of an aromatic alcohol such as benzyl (meth) acrylate with (meth) acrylic acid; glycidyl (meth)
Acrylate or hydroxyalkyl ester of (meth) acrylic acid and capric acid, lauric acid, linoleic acid,
Addition product of monocarboxylic acid compound such as oleic acid, addition product of (meth) acrylic acid and monoepoxy compound such as "CARDURA E10" (manufactured by Shell Chemical Co.); styrene, α
-Vinyl aromatic compounds such as methylstyrene, vinyltoluene, p-chlorostyrene, p-tert-butylstyrene; 2-hydroxyethyl (meth) acrylate, 2-
Hydroxyalkyl (meth) acrylates such as hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, Α, β-ethylenically unsaturated carboxylic acids such as citraconic acid; glycidyl group-containing compounds such as glycidyl (meth) acrylate, vinyl glycidyl ether, and allyl glycidyl ether; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N
-Carboxylic amide compounds such as alkoxymethylated (meth) acrylamide, diacetone acrylamide, N-methylol (meth) acrylamide; P-styrene sulfonamide, N-methyl-P-styrene sulfonamide, N, N-dimethyl- Sulfonamide group-containing compounds such as P-styrenesulfonamide; "Biscoat 8
"F", "Viscoat 8FM", "Viscoat 3F",
"Viscoat 3FM" (both are Osaka Organic Chemical Co., Ltd.)
Fluorine atom-containing compounds such as (meth) acrylates having a fluorine atom in the side chain, perfluorocyclohexyl (meth) acrylate, perfluorocyclohexyl ethylene; polyvinyl compounds such as ethylene glycol di (meth) acrylate and divinylbenzene Etc. can be mentioned, and these can be used individually or as a mixture of 2 or more types.

Polyvinyl compounds are used as a part of the radically polymerizable unsaturated monomer for emulsion polymerization, or each has a complementary functional group capable of reacting with each other and bonding in addition to the polymerizable unsaturated group. The inside of the polymer particles can be crosslinked by a method of copolymerizing at least two kinds of polymerizable unsaturated monomers and reacting complementary functional groups with each other. By crosslinking the inside of the polymer particles,
Generally, the emulsion stability of polymer particles can be improved.

Examples of the combination of the above-mentioned complementary functional groups include (1) epoxy group / carboxyl group, (2) epoxy group / amino group, (3) alkoxysilyl group / hydroxyl group and the like. Taking the combination of the above-mentioned (1) as an example, a combination of an epoxy group-containing monomer such as glycidyl acrylate and glycidyl methacrylate and a carboxyl group-containing monomer such as acrylic acid and methacrylic acid. Is mentioned. As the above emulsion polymerization method, a known emulsion polymerization method can be used.

When the polymer fine particles are obtained by polymerizing a radically polymerizable unsaturated monomer in an organic liquid in the presence of a dispersion stabilizer resin, the organic liquid may be a dispersion produced by the polymerization. Although the polymer particles are not substantially dissolved, an organic liquid which is a good solvent for the dispersion stabilizer resin and the radically polymerizable unsaturated monomer is included. Specific examples of the organic liquid include hexane, heptane,
Aliphatic hydrocarbons such as octane; Aromatic hydrocarbons such as benzene, toluene, xylene; Alcohols such as methyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, octyl alcohol, cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, etc. Ketones such as ethers, methyl isobutyl ketone, diisobutyl ketone, methyl ethyl ketone, methyl hexyl ketone, ethyl butyl ketone;
Esters such as ethyl acetate, isobutyl acetate, amyl acetate and 2-ethylhexyl acetate can be mentioned. These organic liquids may be used alone or as a mixture of two or more kinds, but generally they are mainly aliphatic hydrocarbons, and aromatic hydrocarbons, alcohols and ethers are appropriately added. , A combination of a ketone, an ester, and the like is preferably used.

As the dispersion stabilizer resin, any of the known resins conventionally used in the field of non-aqueous dispersion can be used, and examples thereof include the following. A self-condensation polyester of a fatty acid having a hydroxyl group such as 12-hydroxystearic acid and glycidyl acrylate or glycidyl methacrylate are added to give about 1.
A polyester macromer having 0 polymerizable double bond introduced. The above polyester macromer and methyl methacrylate and / or other (meth) acrylic acid ester,
A comb-shaped polymer made by copolymerizing vinyl monomers.

A small amount of glycidyl (meth) acrylate is copolymerized in the above, and (meth) acrylic acid is subsequently added to the glycidyl group to introduce a double bond. A hydroxyl group-containing acrylic copolymer obtained by copolymerizing at least 20% of a (meth) acrylic acid ester of a monoalcohol having 4 or more carbon atoms.

An acrylic copolymer in which 0.3 or more double bonds are introduced per molecule based on the number average molecular weight. As a method for introducing a double bond, for example, a method in which a small amount of glycidyl (meth) acrylate is copolymerized in the original acrylic copolymer and then (meth) acrylic acid is added to the glycidyl group Is mentioned.

Alkyl melamine resin having a high tolerance of mineral spirits. An alkyd resin having an oil length of 15% or more and / or one having a polymerizable double bond introduced therein. Examples of the method of introducing the double bond include a method of adding glycidyl (meth) acrylate to the carboxyl group in the alkyd resin.

An oil-free polyester resin having a high mineral spirit tolerance, an alkyd resin having an oil length of less than 15%, and / or a polymer having a polymerizable double bond introduced therein. Cellulose acetate butyrate introduced with a polymerizable double bond. Examples of the method of introducing the double bond include a method of adding isocyanatoethyl methacrylate to cellulose acetate butyrate.

These dispersion stabilizer resins may be used alone or in combination of plural types. Among the above dispersion stabilizer resins, particularly preferable dispersion stabilizers in the present invention can be dissolved in a relatively low polar solvent such as an aliphatic hydrocarbon and can also satisfy the requirements for coating film performance to some extent. As the dispersion stabilizer resin satisfying the above conditions, the molecular weight, the glass transition temperature, the polarity, the hydroxyl value, the acid value, etc., can be easily adjusted and the weather resistance is excellent. Acrylic polymers of and are preferred.

Further, an acrylic polymer having an average of about 0.2 to 1.2 polymerizable double bonds capable of graft polymerization with the dispersed fine particles in the molecule is preferable.

In the production of the above-mentioned non-aqueous dispersion, the radically polymerizable unsaturated monomer which is subjected to polymerization to form polymer fine particles has excellent polymerizability and a polymer formed from the monomer is It is necessary to have a solubility parameter (SP value) higher than that of the dispersion stabilizer resin, and generally, the SP value of the polymer is preferably in the range of about 8.0 to 9.5.

In the present invention, "solubility parameter (S
P value) "can be theoretically calculated by the following formula. SP value: δ δ × 100 = (δ _a × A) + (δ _b × B) + (δ _c × C) + (where δ: solubility parameter δ _a , δ of copolymer)
_b , δ _c ···: solubility parameter of monomers a, b, c ··· A, B, C ···: monomer a, b, c ···
(% By weight in the copolymer)

The radical-polymerizable unsaturated monomer forming the polymer fine particles is appropriately selected from those fried as the radical-polymerizable unsaturated monomer forming the polymer fine particles by the emulsion polymerization. can do.
As in the case of the emulsion polymerization method as a part of the radically polymerizable unsaturated monomer, a poly vinyl compound may be used, or the reaction between complementary reactive groups may be used to crosslink the inside of the polymer fine particles. It is possible to improve the stability of the non-aqueous dispersion liquid of polymer particles by this crosslinking.

As the combination of the above-mentioned complementary functional groups,
(1) epoxy group / carboxyl group, (2) epoxy group / amino group, (3) alkoxysilyl group / hydroxyl group,
Examples include combinations of (4) hydroxyl group / isocyanate group, (5) isocyanate group / amino group, and (6) epoxy group / phosphoric acid group.

The particle size of the polymer fine particles obtained by the above emulsion polymerization method or non-aqueous dispersion polymerization method is generally 1
It is in the range of 0 to 1,000 nm, preferably 50 to 500 nm.

When the polymer fine particles are obtained by an emulsion polymerization method, the emulsion liquid is dried by a spray drying method or the like to obtain polymer fine particle powder, or water in the emulsion liquid is replaced with an organic solvent. It is then used as a polymer fine particle dispersion in an organic solvent. When the polymer fine particles are obtained by the non-aqueous dispersion method, the non-aqueous dispersion liquid can be used as it is, or can be dried and used as a powder.

The curing catalyst which is the component (d) in the composition of the present invention is generally used as a curing catalyst for alkoxysilyl groups, and has the general formula [1] in the component (a).
The alkoxysilyl group derived from the compound is a catalyst that accelerates the reaction of hydrolyzing in the presence of water to form a silanol group, and then the silanol group is dehydrated and condensed to bond and crosslink. It provides curability.

Specific examples of the component (d) curing catalyst include:
For example, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, mono-n-propylphosphoric acid, monoisopropylphosphoric acid,
Mono-n-butyl phosphoric acid, monoisobutyl phosphoric acid, mono tert
-Butyl phosphoric acid, monooctyl phosphoric acid, monodecyl phosphoric acid and other monoalkyl phosphoric acids, di-n-propyl phosphoric acid, diisopropyl phosphoric acid, di-n-butyl phosphoric acid, diisobutyl phosphoric acid, di-n-butyl phosphoric acid
tert-Butyl phosphoric acid, dioctyl phosphoric acid, didecyl phosphoric acid, and other dialkyl phosphoric acids, β-hydroxyethyl (meth) acrylate phosphoric acid esters, mono-n-propyl phosphorous acid, monoisopropyl phosphorous acid, mono-n-butyl phosphorous acid, monoisobutyl phosphorous acid , Mono-tert-butyl phosphite, monooctyl phosphite, monodecyl phosphite and other monoalkyl phosphites, di-
n-propylphosphorous acid, diisopropylphosphorous acid, di-n-
Butyl phosphite, diisobutyl phosphite, ditert butyl phosphite, dioctyl phosphite, didecyl phosphite and other dialkyl phosphite acid compounds; tin octylate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin maleate And tin-containing compounds such as butylamine, tert-butylamine, dibutylamine, hexylamine, ethylenediamine, triethylamine, isophoronediamine, imidazole, lithium hydroxide, potassium hydroxide and sodium methylate.

These can be used alone or as a mixture of two or more kinds. The composition of the present invention is generally provided as a two-pack type, and the base and the curing catalyst are mixed and used immediately before use.

In the composition of the present invention, the compounding ratio of the acrylic polymer as the component (a) and the polymer fine particles as the component (c) is not particularly limited, but the solid content weight ratio of the two is (). a) / (c) is preferably in the range of 30/70 to 99/1, more preferably 40/60 to 9
The range is 0/10. The ratio of (a) / (c) is 30 /
When it is less than 70 [when (a) is small], the gloss of the obtained coating film is apt to decrease, while (a) /
When the ratio of (c) is larger than 99/1, the sagging limit film thickness becomes small and the suitability for thick film coating deteriorates, and the mechanical properties such as impact resistance and flexibility of the coating film easily deteriorate.

The mixing ratio of the curing catalyst which is the component (d) in the composition of the present invention is not particularly limited, but generally, the total solid content of the acrylic polymer (a) and the polymer fine particles (c) is 100. The amount is preferably 0.01 to 10 parts by weight with respect to parts by weight.

The mixing ratio of the volatile organic liquid diluent which is the component (b) in the composition of the present invention is not particularly limited, and may be in the range where the composition of the present invention does not hinder coating. Generally, 40 to 40 parts by weight based on 100 parts by weight of the total solid content of the acrylic polymer (a) and the polymer fine particles (c).
It is in the range of 300 parts by weight.

The composition of the present invention comprises the above (a), (b),
In addition to the components (c) and (d), color pigments, extender pigments, dyes, dehydrating agents, plasticizers and the like can be added as necessary. Known plasticizers include, for example, low-molecular-weight plasticizers such as dimethyl phthalate and dioctyl phthalate, high-molecular-weight plasticizers such as vinyl polymer plasticizers and polyester plasticizers. Dissolved in a radically polymerizable unsaturated monomer,
It may be distributed in fine polymer particles obtained by polymerization, or may be mixed at the time of forming a paint.

If desired, amino resins, epoxy resins, polyisocyanates and the like which are generally used as a curing agent may be used in combination. Further, other acrylic resins, alkyd resins, polyester resins, epoxy resins and the like can be blended and used.

The composition of the present invention may be a two-part type comprising a curing catalyst (d) and a base which is a mixture of the remaining components other than the curing catalyst (d). Can be used for

The curable composition of the present invention can be easily crosslinked and cured by drying at room temperature or heating at a low temperature of 100 ° C. or lower in the presence of water. In room temperature drying, water is added to the composition or coating is performed, or the composition is simply exposed to the air after coating, and can be sufficiently cured in about 8 hours to 7 days without heating at all. it can. Also, a small amount of water, such as moisture in the air, is sufficient for curing. When water is added before coating, an addition amount of about 0.1 to 1% by weight is usually sufficient.

When the curable composition of the present invention is used as a coating material, the object to be coated is a substrate having a surface of a metal such as iron, zinc or aluminum or an alloy of these metals, wood, concrete or slate. For example, these surfaces may be subjected to chemical conversion treatment, sealer coating, primer coating and the like. The coating amount is not particularly limited, but is usually 25 to 50 μm in dry film thickness.
It is applied so that it becomes m.

[0054]

According to the composition of the present invention, the composition of the present invention has low-temperature curing property, good storage stability, coating surface condition, chemical resistance, water resistance, and impact resistance and flex resistance. It is possible to form a coating film having excellent physical properties.

The composition of the present invention contains polymer fine particles, and the resulting coating film is a photo-chemically stable coating film having a siloxane bond in the continuous phase of the coating film. Since the discontinuous phase is polymer fine particles and the coating film is reinforced by the fine particles, it is considered that the above mechanical properties, weather resistance and the like are excellent. As described above, the composition of the present invention can be easily cross-linked and cured at a low temperature of 100 ° C. or lower in the presence of a small amount of water, for example, water in the air, as described above, by the accelerating action of the curing catalyst.

[0056]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In each example, parts and% are based on weight in principle. Synthesis of Acrylic Polymer Production Example 1 100 parts of xylene was heated to 120 ° C., and a mixture of the following monomers and an initiator was added dropwise over 3 hours. After completion of the dropping, aging was carried out for 2 hours to obtain an acrylic polymer (a-1) solution. Styrene 10 parts n-Butylmethacrylate 40 parts Methylmethacrylate 35 parts 2-Hydroxyethylmethacrylate 5 parts γ-methacryloyloxypropyltrimethoxysilane 10 parts 2,2′-azobisisobutyronitrile 2 parts Acryl polymer obtained ( a-1) The solution has a nonvolatile content of about 5
The viscosity was 0%, the viscosity (Gardner viscosity, 25 ° C., the same applies hereinafter) C, and the weight average molecular weight of the acrylic polymer (a-1) was about 10,000.

Production Example 2 80 parts of toluene was heated to 110 ° C., and a mixture of the following monomers and an initiator was added dropwise over 3 hours. After completion of dropping, aging was carried out for 2 hours to obtain an acrylic polymer (a-2) solution having a solid content of about 55%. 2-Ethylhexylmethacrylate 25 parts Lauryl methacrylate 30 parts n-Butyl acrylate 20 parts 2-Hydroxyethyl methacrylate 5 parts γ-methacryloyloxypropyltrimethoxysilane 20 parts 2,2′-azobisisobutyronitrile 2 parts Obtained The acrylic polymer (a-2) solution has a nonvolatile content of about 5
The acrylic polymer (a-2) had a viscosity of 5% and a weight average molecular weight of about 16,000.

Production of Non-Aqueous Dispersion of Polymer Particles Production Example 3 80 parts of xylene was heated to 120 ° C., and the following mixture of monomers and initiator was added dropwise over 3 hours. After finishing the dropping
Aging was carried out for 2 hours to obtain an acrylic polymer solution having a solid content of about 55%. Styrene 15 parts n-Butyl acrylate 35 parts 2-Ethylhexyl methacrylate 20 parts Lauryl methacrylate 15 parts 2-Hydroxyethyl acrylate 15 parts 2,2'-Azobisisobutyronitrile 3 parts Then 1 mol of isophorone diisocyanate and 2-hydroxyethyl methacrylate. 3 parts of an isocyanate group-containing adduct with 1 mol was added to 100 parts of the acrylic polymer solution and heated at 120 ° C. for 3 hours to obtain a polymerizable unsaturated group-containing acrylic polymer solution having a solid content of about 56%. ..

Obtained Polymerizable Unsaturated Group-Containing Acrylic Polymer Solution 80 parts Heptane 80 parts Xylene 30 parts The above mixture was placed in a flask, heated to reflux, and the following monomers and polymerization initiator were added dropwise over 3 hours. After completion of dropping, the mixture was aged for 2 hours. Methyl methacrylate 70 parts Acrylonitrile 15 parts 2-Hydroxyethyl acrylate 15 parts 2,2'-Azobisisobutyronitrile 1 part Then, 50 parts of heptane is removed by decompression, and 50 parts of xylene is added to the non-aqueous polymer particles. A dispersion liquid (b-1) was obtained. The obtained dispersion was a milky white stable low-viscosity polymer dispersion having a nonvolatile content of about 50%, a viscosity B and a particle size of polymer particles of 0.2 to 0.3 μm.

Production Example 4 80 parts of xylene was heated to 120 ° C., and the following mixture of monomers and initiator was added dropwise over 3 hours. After finishing the dropping
After aging for 2 hours, an acrylic polymer having a solid content of about 55% was obtained. n-Butylmethacrylate 42 parts 2-Ethylhexylmethacrylate 15 parts Laurylmethacrylate 20 parts 2-Hydroxyethylmethacrylate 20 parts Glycidylmethacrylate 3 parts 2,2'-Azobisisobutyronitrile 3 parts then acrylic acid 1 part to the above acrylic polymer Solution 100
Part, and heated at 120 ° C. for 3 hours to give a solid content of about 56%
A polymerizable unsaturated group-containing acrylic polymer of was obtained.

Obtained Polymerizable Unsaturated Group-Containing Acrylic Polymer Solution 80 parts Heptane 80 parts Xylene 30 parts The above mixture was charged into a flask, heated to reflux, and the following monomers and polymerization initiator were added dropwise over 3 hours. After completion of dropping, the mixture was aged for 2 hours. Methyl methacrylate 56 parts Methyl acrylate 20 parts 2-Hydroxyethyl acrylate 20 parts Methacrylic acid 2 parts Glycidyl methacrylate 2 parts 2,2'-Azobisisobutyronitrile 1 part Then, 50 parts of heptane is removed by decompression and 50 parts of xylene. Was added to obtain a non-aqueous dispersion liquid (b-2) of polymer particles. The obtained dispersion was a milky white stable low-viscosity polymer dispersion having a nonvolatile content of about 50%, a viscosity B and a particle size of polymer particles of 0.2 to 0.3 μm.

Production Example 5 5.1 parts of eleminol JS-2 (manufactured by Sanyo Kasei Co., Ltd., sulfosuccinic acid type allyl group-containing anionic reactive emulsifier aqueous solution, solid content 39%) in 354 parts of deionized water (solid content) 2 parts) were mixed, the temperature was raised to 90 ° C., and the following monomer mixture and polymerization initiator solution were added dropwise over 3.5 hours. After the dropping, keep the solid content at 20 ° C for 30 minutes,
% Aqueous gelled particulate polymer was obtained. Monomer mixture styrene 47 parts n-butyl acrylate 47 parts 1,6-hexanediol diacrylate 6 parts polymerization initiator solution deionized water 50 parts 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -Propionamide] 1.25 parts

Then, it was pulverized by a spray dryer method, and xylene was used as a solvent to obtain a 20% polymer fine particle dispersion (b-3). This one has viscosity A
1. It was a milky white stable low-viscosity polymer dispersion having a particle size of 0.1 μm.

Preparation of Pigment Paste Production Example 6 Raw materials having the following composition were put in a 4-liter stainless steel container,
Pigment paste A was obtained by dispersing the pigment for 30 minutes with a tabletop sand mill. Acrylic polymer (a-1) solution 50 parts Kaneka Zemlac ZW806Z (Note 1) 4 parts Xylene 6 parts Titanium white CR-93 (Note 2) 80 parts (Note 1) Kaneka Zemlac ZW806Z: Kaneka Fuchi Chemical Industry Co., Ltd. ), Dehydrating agent (Note 2) Titanium white CR-93: White pigment, manufactured by Ishihara Sangyo Co., Ltd.

Production Example 7 Raw materials having the following composition were placed in a 4-liter stainless steel container,
Pigment paste B was obtained by dispersing the pigment for 30 minutes with a tabletop sand mill. Acrylic polymer (a-2) solution 45.5 parts Kaneka Zemlac ZW806Z 4 parts Xylene 10.5 parts Titanium white CR-93 80 parts

Production Example 8 Raw materials having the following composition were placed in a 4-liter stainless steel container,
Pigment paste C was obtained by dispersing the pigment for 30 minutes with a tabletop sand mill. Acrylic polymer (a-1) solution 50 parts Kaneka Zemlac ZW806Z 4 parts Xylene 6 parts Titanium white CR-93 80 parts Disparlon 6900-20X 3 parts

Example 1 140 parts of the pigment paste A obtained in Preparation Example 5 in 90 parts of the acrylic polymer (a-1) solution obtained in Preparation Example 1 and a non-aqueous dispersion of the polymer particles obtained in Preparation Example 3 ( b-1) 60 parts and 10 parts of xylene were added and uniformly mixed to obtain a paint base.

Examples 2 to 6 and Comparative Examples 1 to 2 A coating base was obtained in the same manner as in Example 1 except that the types and amounts of raw materials used were as shown in Table 1 below. The blending amount in Table 1 is shown in parts by weight. Comparative Example 3 An attempt was made to obtain a pigment paste in the same manner as in Production Example 7, except that the non-aqueous dispersion liquid (b-1) obtained in Production Example 3 was used instead of the acrylic polymer (a-2) solution. However, pigment dispersion could not be performed.

Storage stability tests were carried out on the paint bases obtained in Examples 1-5 and Comparative Examples 1-2. The amount of dibutyltin dilaurate as a curing catalyst shown in Table 1 was added to the paint base obtained in each example to obtain a colored paint composition, and the sag limit film thickness of this composition was measured. The coating composition is applied to a polished mild steel plate so that the dry film thickness is 30 μm,
Regarding the coating film after being dried at room temperature for 7 days, the coating surface state,
Gloss, water resistance, alkali resistance, acid resistance, weather resistance, impact resistance, and bending resistance were tested. The gel fraction of the isolated coating film of this coating composition was also measured.

Test method Storage stability: The paint base was sealed and stored in a thermostatic chamber at 40 ° C., and the number of days until it thickened to form a pudding was examined. The case where no significant increase in viscosity was observed even after one month had passed was rated as ◯ (good). Sag limit film thickness: The minimum film thickness (dry film thickness, μm) at which sagging occurred was measured by performing a gradient coating of the film thickness.

Coating state: visually observed, JIS K
Evaluation was performed according to 5400. Those with no abnormalities were marked with a circle. Gloss: 60 degree gloss and 20 degree gloss of the dry coating film were measured. Water resistance: The state of the coated surface after immersion in tap water at 40 ° C. for 168 hours was examined. Those with no abnormalities were marked with a circle. Alkali resistance: It was examined by the state of the coated surface after being immersed in a 5% NaOH aqueous solution (25 ° C.) for 24 hours. Good one ○
And Acid resistance: The state of the coated surface after immersion in a 5% HCl aqueous solution (25 ° C.) for 24 hours was examined. Those with no abnormalities were marked with a circle. Weather resistance: Using a sunshine weather ometer,
The gloss retention of the coating film was examined after the 1,000-hour test.

Impact resistance: Using a DuPont impact tester,
A weight of 300 g was dropped onto the surface of the coating with a drop weight height of 50 cm at a diameter of 1/2 inch of the impact core, and it was examined whether or not the coating film had abnormalities such as cracks and peeling. ○ If there is no abnormality
And Bend resistance: J using a bend resistance tester (10 mm diameter core rod)
The test was performed according to IS K 5400. Those with no abnormalities such as cracks and peeling were rated as ○. Gel fraction: The paint of each example was applied to a tin plate to give a dry film thickness of 30μ.
The coating was peeled off to obtain an isolated coating film after the coating film was peeled off after drying for 7 days at room temperature. Place the isolated coating in an equal weight mixture of acetone / methanol held at reflux temperature and
The residual rate (%) of the coating film after time extraction was examined.

[0073]

[Table 1]

Claims (1)

[Claims] 1. (a) General formula [1] [In formula, A shows -COO- or a phenylene group. R ₁
Is a hydrogen atom or a methyl group, R ₂ is a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, R ₃ and R ₄ are the same or different and are a phenyl group, an alkyl group having 1 to 6 carbon atoms, or An alkoxy group having 1 to 10 carbon atoms and R ₅ each represent an alkyl group having 1 to 10 carbon atoms. n shows the integer of 1-100. ] An acrylic polymer containing an alkoxysilane group-containing vinyl compound represented by the following as an essential monomer component, (b) a volatile organic liquid diluent capable of dissolving the acrylic polymer (a), (c) in the diluent (b) A curable composition comprising polymer fine particles which are not dissolved in a solution of the acrylic polymer (a) and are stably dispersed, and (d) a curing catalyst.