JP6133785B2 - Curable resin composition for coating and automotive clear coating agent - Google Patents

Description

The present invention is capable of forming a coating film under mild curing conditions, imparts excellent solvent resistance, acid resistance and chemical resistance, and has excellent scratch resistance and stain resistance, as well as coating curing. The present invention relates to a conductive resin composition and an automobile clear coating agent containing the resin composition.

The demand for the durability of the formed coating film is increasing for the top coating used to form a coating film on automobiles, building materials, plastic parts, films and the like. In addition to the appearance, specifically, coating film performance excellent in weather resistance, solvent resistance, acid resistance, chemical resistance, scratch resistance, etc. is required. In order to express such high coating film performance and appearance, a two-component curable coating material has been conventionally used.

Examples of paints used to protect automobiles, building materials, plastic parts, films, etc., and to provide design properties include acrylic lacquer paints, two-part curable urethane resin paints, and two-part curable acrylic silicon resin paints. There is. Acrylic lacquer paint is a one-pack paint that does not involve a crosslinking reaction of the resin and is easy to handle without the need for compounding a curing agent, but the resulting coating film is inferior in chemical resistance.

Conventionally, paints containing melamine resins such as alkyd melamine and acrylic melamine have been mainly used for painting automobiles, industrial machines, steel furniture, etc. (Patent Document 1). A 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, and etching, whitening, spots and the like are generated on the coating film.

In order to eliminate such drawbacks, so-called urethane paints using a reaction between a hydroxyl group and an isocyanate without using a melamine polymer have been proposed (Patent Documents 2 and 3). Although each is a curable resin composition comprising a combination of a hydroxyl group-containing resin and a polyfunctional isocyanate compound or a blocked isocyanate, although the acid resistance has been improved, the resulting coating film has insufficient scratch resistance and stain resistance. Absent.

The method of forming a coating film by applying a thermosetting two-component urethane paint (Patent Document 4) needs to increase the crosslinking density in order to obtain scratch resistance and chemical resistance, and has a high hydroxyl value. Will be. However, both scratch resistance and chemical resistance are not sufficient levels, and there is a problem that adhesion to a plastic substrate is further reduced.

Therefore, for the purpose of improving the scratch resistance, the use of polycarbonate diol in a urethane cross-linking paint using a hydroxyl group-containing resin such as an acrylic resin as a base resin and a polyisocyanate compound as a cross-linking agent has been studied (Patent Literature). 5). However, the polycarbonate diol has insufficient compatibility with the acrylic polyol, and further, when a large amount of the polycarbonate diol is blended in order to ensure scratch resistance, the crosslinking density is lowered, so that the weather resistance and solvent resistance are insufficient. There is a problem.

On the other hand, it has also been proposed to use a paint using a polymer having a hydrolyzable silyl group (Patent Document 6). By using a vinyl polymer having a hydrolyzable silyl group and an alcoholic hydroxyl group, a stable siloxane bond or siloxy bond is formed and cured by baking and drying, so that a coating film excellent in acid resistance and weather resistance can be obtained. Can be formed. However, there is a problem that the obtained coating film has insufficient scratch resistance.

In addition, although the two-component curable acrylic silicone resin paint can obtain excellent solvent resistance and chemical resistance, it is inferior in workability, recoatability, and coating film appearance as compared with the two-component curable urethane resin paint. There is a problem.

In addition, a method in which a polyfunctional monomer or oligomer is used as a main constituent and UV curing is performed using a photo radical generator has been reported (Patent Document 7). Since this method does not require heat drying for curing, there is an advantage that a substrate having a high hardness can be obtained in a short time without damaging a substrate such as plastic. However, there are problems such as poor flexibility and cracking or peeling of the coating film by impact.

For this reason, it can be applied to automobiles, building materials, plastic parts, films, etc., and it has coating performance with excellent weather resistance, solvent resistance, acid resistance, chemical resistance, scratch resistance, stain resistance, etc., and is inexpensive. Development of a coating agent (for example, an automobile clear coating agent) has been demanded.

JP-A-5-202335 Japanese Patent Laid-Open No. 10-28931 Japanese Patent Laid-Open No. 9-132753 JP 2008-296539 A International Publication No. 2007/119305 Pamphlet JP-A-7-82521 Japanese Patent Laid-Open No. 5-230397

The problem of the present invention is that it is possible to form a coating film under mild curing conditions even on materials that cannot be heated excessively, such as plastic moldings and films, and weather resistance, solvent resistance, It is to provide a curable resin composition for coating that is excellent in chemical properties, scratch resistance, etc., and further to provide a curable resin composition for coating that can provide scratch repairability against scratches. Another object of the present invention is to provide an automobile clear coating agent having acid resistance, chemical resistance, scratch resistance, and contamination resistance.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a specific vinyl copolymer having a hydrolyzable silicon group and a hydroxyl group, a polyisocyanate compound, and a curing for coating containing a specific curing catalyst. The curable resin composition can be cured under mild curing conditions, and has good weather resistance, solvent resistance, acid resistance, chemical resistance, scratch resistance, and excellent adhesion to various substrates. The present inventors have found that a coating film having excellent stain resistance can be formed.

That is, the present invention
(A) The main chain is a (meth) acrylic copolymer chain, and the general formula (I):
R ² _a
｜
-Si- (OR ¹ ) _3-a (I)
Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 25 carbon atoms, and an aralkyl having 7 to 12 carbon atoms. And represents a monovalent hydrocarbon group selected from the group a represents an integer of 0 to 2.)
A vinyl-based copolymer having 10 or more hydrolyzable silicon groups represented by the formula, and having 10 or more hydroxyl groups in the main chain terminal and / or side chain,
(B) a compound containing two or more isocyanate groups, and
(C) The present invention relates to a multi-component curable resin composition for coating, comprising a hydrolyzable silicon group and an isocyanate curing catalyst.

The vinyl copolymer (A) is preferably a polymer having a hydroxyl value of 50 to 300 mgKOH / g.

The vinyl copolymer (A) preferably has a glass transition temperature of -20 to 80 ° C.

The vinyl copolymer (A) is a monomer having a hydroxyl group bonded to a (meth) acryloyl group via an alkylene group having 3 or more carbon atoms and / or a polylactone system having a carbon-carbon double bond at the terminal. It is preferable to be obtained by copolymerizing monomers.

It is preferable that the curing catalyst (C) is at least one selected from the group consisting of a tin compound, an aluminum chelate compound, and a tertiary amine compound having no active hydrogen group.

The curing catalyst (C) is preferably a cyclic amine compound.

Moreover, this invention relates to the motor vehicle clear coating agent containing the multi-component curable resin composition for coating of this invention.

Furthermore, the present invention relates to a coated product coated with the multi-component curable resin composition for coating of the present invention.

The multi-component curable resin composition for coating of the present invention can be cured under mild curing conditions to obtain a coating film having good weather resistance, solvent resistance, acid resistance, chemical resistance, and scratch resistance. be able to. Furthermore, it has a flaw-repairing property against scratches, and can form a coating film with excellent stain resistance.

Hereinafter, the present invention will be described in detail based on an embodiment thereof.
The multi-component curable resin composition for coating of the present invention contains the components (A) to (C).
First, each component will be described.

As the component (A) vinyl copolymer (A), the main chain is a (meth) acrylic copolymer chain, and the main chain terminal and / or side chain has the general formula (I):
R ² _a
｜
-Si- (OR ¹ ) _3-a (I)
Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 25 carbon atoms, and an aralkyl having 7 to 12 carbon atoms. And represents a monovalent hydrocarbon group selected from the group a represents an integer of 0 to 2.)
As long as it is a vinyl copolymer having 10 or more hydrolyzable silicon groups represented by the formula and 10 or more hydroxyl groups at the main chain terminal and / or side chain, it can be used without any particular limitation. .

The hydrolyzable silicon group (hereinafter also referred to as a hydrolyzable silyl group) is a group containing a silicon atom to which a hydrolyzable group is bonded. The hydrolyzable silyl group may be bonded to the main chain terminal of the component (A), may be bonded to the side chain, or may be bonded to the main chain terminal and the side chain.

The hydroxyl group may be bonded to the main chain end of the component (A), may be bonded to the side chain, or may be bonded to the main chain end and the side chain.

In the said general formula (I), it is preferable that a is 0 or 1 from the point that the sclerosis | hardenability of the composition of this invention becomes favorable. When there are a plurality of OR ¹ or R ² , they may be the same or different.

Among these, R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms from the viewpoint that the curing speed is high, and the resulting coating film has excellent solvent resistance, chemical resistance, and acid resistance. It is more preferably an atom or an alkyl group having 1 to 2 carbon atoms.

Further, from the viewpoint of a high curing rate and a high degree of crosslinking, R ² is preferably not sterically large, and a hydrogen atom, an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group, and a phenyl group are preferable. And more preferably an alkyl group having 1 to 3 carbon atoms.

The vinyl copolymer (A) preferably has a glass transition temperature of -20 to 80 ° C from the viewpoint of excellent balance between chemical resistance and scratch resistance. When the glass transition temperature is less than −20 ° C., tack remains in the coating film and the solvent resistance and chemical resistance tend to deteriorate. On the other hand, when the glass transition temperature exceeds 80 ° C., although the solvent resistance and chemical resistance are excellent, the coating film becomes brittle and the scratch resistance is not sufficient.

The hydroxyl value of the vinyl copolymer (A) is preferably 50 to 300 mgKOH / g.

The vinyl copolymer (A) is a monomer having a hydroxyl group bonded to a (meth) acryloyl group via an alkylene group having 3 or more carbon atoms and / or a polylactone unit having a carbon-carbon double bond at the terminal. It is preferably obtained by copolymerizing a monomer.

Although it does not specifically limit as a manufacturing method of a vinyl type copolymer (A), For example, (a) Hydrolysis in the method in which the main chain is a (meth) acrylic-type copolymer chain is obtained. It is obtained by a method of polymerizing a polymerizable silyl group-containing vinyl monomer, (b) a hydroxyl group-containing vinyl monomer, and (c) another polymerizable vinyl monomer.

(A) Hydrolyzable silyl group-containing vinyl monomer As the hydrolyzable silyl group-containing vinyl monomer (a), a vinyl monomer having an alkoxysilyl group represented by the following general formula (I) The body is useful.

R ² _a
｜
-Si- (OR ¹ ) _3-a (I)
Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 25 carbon atoms, and an aralkyl having 7 to 12 carbon atoms. And represents a monovalent hydrocarbon group selected from the group a represents an integer of 0 to 2.)

Specific examples of the hydrolyzable silyl group-containing vinyl monomer (a) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (n-propoxy) silane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltris. (Β-methoxyethoxy) silane, allyltriethoxysilane, trimethoxysilylpropylallylamine, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxy Propyltriisopropoxysilane, γ- (meth) acryloxypropyltris (β-methoxyethoxy) silane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (Meta) Acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropyldimethylethoxysilane, N-vinylbenzyl-γ-aminopropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, 3- (N-styrylmethyl-2- Aminoethylamino) propyltrimethoxysilane, (meth) acryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride, vinyltriacetoxysilane, vinyltrichlorosilane, etc. Γ- (meth) acryloxypropyltrimethoxysilane and γ- (meth) acryloxypropyltriethoxysilane, which are group-containing monomers, are preferable from the viewpoint of stability.

These hydrolyzable silyl group-containing vinyl monomers (a) may be used alone or in combination of two or more.

In the present specification, “(meth) acryl” means acrylic and / or methacrylic. “(Meth) acryloxy” means methacryloxy and / or acryloxy. “(Meth) acrylate” means acrylate and / or methacrylate.

The hydrolyzable silyl group-containing vinyl monomer (a) contains 10 to 30, particularly preferably 10 to 20, hydrolyzable silyl groups per molecule of the vinyl copolymer (A). It is preferable to use it from the viewpoint of providing sufficient solvent resistance and chemical resistance and improving scratch resistance. The number of hydrolyzable silyl groups in one molecule depends on the ratio (number of moles) of the hydrolyzable silyl group-containing vinyl monomer (a) in the monomer mixture and the vinyl monomer (a). It can be obtained by calculation from the number average molecular weight.

The hydrolyzable silyl group-containing vinyl monomer (a) is preferably blended in an amount of 5 to 80 parts by weight in 100 parts by weight of the total monomers of the vinyl copolymer (A). It is particularly preferable to blend in an amount of not less than 60 parts by weight.

(B) Hydroxyl group-containing vinyl monomer The hydroxyl group-containing vinyl monomer (b) is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol Hydroxyl group-containing vinyl monomers such as (meth) acrylamide and 4-hydroxystyrene vinyltoluene; PlaccelFA-1, PlaccelFA-4, PlaccelFM-1, PlaccelFM-4 (manufactured by Daicel Chemical Co., Ltd.) Modified lactone or polyester having a polymerizable carbon-carbon double bond at the end thereof; BLEMMER PP series, BLEMMER PE series, BLEMMER PEP series (manufactured by NOF CORPORATION), MA-30, MA-50, MA- 100, MA-150, RA-1120, RA-2614, RMA-564, RMA-568, RMA-1114, MPG130-MA (above, manufactured by Nippon Emulsifier Co., Ltd.) and other polymerizable carbon-carbon double bonds And polyoxyalkylene having a terminal.

Among them, 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate are excellent in reactivity with isocyanates, and can provide a coating film having good weather resistance, chemical resistance, and scratch resistance. 2-hydroxybutyl (meth) acrylate is preferred.

Further, an alkylene group having 3 or more carbon atoms, more preferably 3 to 10 carbon atoms, such as 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and cyclohexanedimethanol mono (meth) acrylate. If a lactone-modified monomer (polylactone monomer) having a terminal carbon-carbon double bond such as Placcel, such as a monomer in which a hydroxyl group is bonded to a (meth) acryloyl group via an acid, is repaired. Is preferable from the point that can be obtained.

These hydroxyl group-containing vinyl monomers (b) may be used alone or in combination of two or more.

As for the amount used, it is said that it is possible to obtain good scratch resistance by designing the vinyl copolymer (A) so that it contains 10 to 50, particularly preferably 10 to 30, hydroxyl groups per molecule. It is preferable from the point. The number of hydroxyl groups in one molecule is determined by calculation from the ratio (number of moles) of the hydroxyl group-containing vinyl monomer (b) in the monomer mixture and the number average molecular weight of the vinyl monomer (A). Can do.

In particular, it is preferable to design the vinyl copolymer (A) to have a hydroxyl value of 50 to 300 mgKOH / g from the viewpoint of improving chemical resistance and scratch resistance.

The hydroxyl group-containing vinyl monomer (b) is preferably blended in an amount of 10 to 80 parts by weight, based on 100 parts by weight of all monomers of the vinyl copolymer (A), and 15 to 60 parts by weight. It is particularly preferable to blend in an amount of no more than parts.

(C) Other polymerizable vinyl monomers Other polymerizable vinyl monomers (c) are not particularly limited as long as they have a carbon-carbon double bond. For example, methyl (meth) C1-C20 alkyl (meth) acrylates such as acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. Cycloalkyl (meth) acrylate having 4 to 20 carbon atoms such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc .; allyl (meth) acrylate; dicyclopentenyl (meth) acrylate; Aralkyl having 3 to 20 carbon atoms such as benzyl (meth) acrylate ( ) Acrylate; epoxy group-containing vinyl monomers such as glycidyl (meth) acrylate, oxycyclohexylinyl (meth) acrylate; acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, crotonic acid , Α-, β-ethylenically unsaturated carboxylic acids such as fumaric acid and citraconic acid or salts thereof (alkali metal salts, ammonium salts, amine salts, etc.); acid anhydrides such as maleic anhydride or those and carbon number 1 -20 half-esters with linear or branched alcohols or salts thereof (alkali metal salts, ammonium salts, amine salts, etc.); styrene sulfonic acid, vinyl sulfonic acid, 2- (meth) acryloxyethyl sulfonic acid, Polymerizable carbon such as 2- (meth) acryloxyethyl phosphate Acids having a carbon double bond, or salts thereof (alkali metal salts, ammonium salts, amine salts, etc.); N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, An amino group-containing vinyl monomer such as N, N-diethylaminoethyl (meth) acrylate or a salt thereof (hydrochloride, acetate, etc.); a quaternary amino group such as trimethylaminoethyl (meth) acrylate hydrochloride; Vinyl monomers having; (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide, acryloylmorpholine, etc. (Meth) acrylamide or their salts (hydrochloride, acetic acid) Salts); nitrogen-containing vinyl monomers such as N-vinylpyrrolidone, N-vinylpyridine, N-vinylimidazole; phosphate esters of hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids; urethane bonds and siloxanes Vinyl compounds such as (meth) acrylate containing a bond; compounds such as AS-6, AN-6, AA-6, AB-6, and AK-5, which are macromonomers manufactured by Toagosei Chemical Co., Ltd .; vinyl acetate, Vinyl esters and allyl compounds such as vinyl propionate, vinyl versatate and diallyl phthalate; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; styrene, α-methylstyrene, chlorostyrene, 4-hydroxystyrene, vinyltoluene Aromatic hydrocarbon monomers such as vinyl methyl ether, Vinyl, vinylidene chloride, chloroprene, propylene, can be cited and other vinyl monomers such as butadiene, may be used alone or in combination of two or more thereof selected from these groups.

The other polymerizable vinyl monomer (c) is preferably blended in an amount of 1 part by weight or more and 85 parts by weight or less, based on 100 parts by weight of the total monomers of the vinyl copolymer (A). It is particularly preferable to add 75 parts by weight or less.

The polymerization method is not particularly limited, and examples thereof include a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, and the like. The solution polymerization method is preferable in terms of ease of synthesis.

Examples of the initiator used for the polymerization include known ones such as organic peroxides such as cumene hydroperoxide, azo compound types such as azobis-2-methylbutyronitrile, potassium persulfate, and the like. Examples include inorganic peroxide-based initiators, redox-based initiators combining peroxides and reducing agents.

The degree of polymerization of the resulting vinyl copolymer (A) is preferably 2000 to 50000 in terms of number average molecular weight, more preferably 3000 to 25000, and particularly preferably 3000 to 10,000. When the number average molecular weight is less than 2,000, an unpolymerized monomer tends to remain, which is not preferable. On the other hand, when the number average molecular weight exceeds 50,000, the resulting curable resin composition often has defects such as stringing during coating. The degree of polymerization can be adjusted by the type and amount of the radical generator, the polymerization temperature, and the use of a chain transfer agent. As the chain transfer agent, n-dodecyl mercaptan, t-dodecyl mercaptan, γ-mercaptopropyltrimethoxysilane and the like can be preferably used.

(B) Compound having two or more isocyanate groups In the present invention, a compound (B) having two or more isocyanate groups (hereinafter referred to as polyisocyanate compound (B)) is used as a crosslinking agent. The number of isocyanate groups is preferably less than 7. Naturally, when the number of isocyanate groups is less than 2, it does not work as a crosslinking agent. However, when the number of isocyanate groups is 7 or more, the crosslinking points may be concentrated so as to inhibit adhesion.

Examples of the polyisocyanate compound (B) include aliphatic or aromatic compounds.

Specific examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, dicyclohexylmethane 4,4′-isocyanate, 2,2,4-trimethyl-1,6-diisocyanate, and isophorone diisocyanate. .

Aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, xylene diisocyanate, polymethylene-polyphenylel-polyisocyanate, etc. There is.
From the viewpoint of no yellowing and good weather resistance, an aliphatic polyisocyanate is more preferable.

The structure of the polyisocyanate compound (B) includes a monomer, a burette type, an adduct type, and an isocyanurate type. These compounds can be used for normal temperature curing, and further, those obtained by masking these isocyanate groups with a blocking agent can also be used. As the blocking agent, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, benzyl alcohol, furfuryl alcohol, cyclohexyl alcohol Phenol, o-cresol, m-cresol, p-cresol, p-tert-butylphenol, thymol, p-nitrophenol, β-naphthol and the like. Moreover, these compounds can also be used in mixture of 2 or more types.

As commercially available polyisocyanate compounds (B), Coronate HL (manufactured by Nippon Polyurethane Industry Co., Ltd.), Duranate P-301, Duranate E-402, Duranate E-405 (above, manufactured by Asahi Kasei Chemicals Corporation) Adduct type such as Duranate 18H, Duranate 21S, Duranate 22A (above, manufactured by Asahi Kasei Chemicals Co., Ltd.) Duranate MFA, Duranate TPA100, Duranate THA100, Duranate TSA100 (above, manufactured by Asahi Kasei Chemicals Corporation), Coronate AP-M, Coronate BI301, Coronate 2507 (above, Nippon Polyurethane Industry Ltd.)), Duranate 17B, Duranate MF (manufactured by Asahi Kasei Chemicals), and the block type and the like.

The use ratio of the vinyl copolymer (A) and the polyisocyanate compound (B) is preferably 0.3 to 2 equivalents, more preferably an isocyanate group with respect to the hydroxyl group in the vinyl copolymer (A). Is 0.5 to 1.5 equivalents. If the polyisocyanate compound is too little, the resulting cured product tends to have poor chemical resistance, and if it is too much, the processability such as impact resistance is poor, and it is difficult to rub at the time of coating. May occur.

(C) Curing Catalyst In the present invention, a hydrolyzable silyl group and isocyanate curing catalyst (C) is used.

The curing catalyst is not particularly limited, and a tin compound, an aluminum chelate compound, and a tertiary amine compound having no active hydrogen group are preferable from the viewpoint of excellent curability of the coating film and overall physical properties of the resulting coating film. .

Specific examples of the tin compound include dioctyltin bis (2-ethylhexylmalate), dioctyltin oxide or a condensate of dibutyltin oxide and silicate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin distearate, dibutyltin diacetylacetate Nert, dibutyltin bis (ethylmalate), dibutyltin bis (butylmalate), dibutyltin bis (2-ethylhexylmalate), dibutyltin bis (oleylmalate), stannous octoate, tin stearate, di-n-butyl There is tin laurate oxide. Dibutyltin bisisononyl-3-mercaptopropionate, dioctyltin bisisononyl-3-mercaptopropionate, octylbutyltin bisisononyl-3-mercaptopropionate, dibutyltin bisisooctylthioglucorate, dioctyltin bisisooctyl Examples thereof include tin compounds having an S atom in the molecule, such as thioglucolate and octylbutyltin bisisooctylthioglucolate.

Among the tin compounds, a compound having an S atom in the molecule is preferable because of good storage stability and usable time when an isocyanate is blended, and in particular, dibutyltin bisisononyl-3-mercaptopropio Nate and dibutyltin bisisooctylthioglucolate are more preferable, and dioctyltin bisisooctylthioglucolate is particularly preferable from the viewpoint of balance between curability, storage stability, and pot life.

Aluminum chelate compounds include ethyl acetoacetate aluminum diisopropylate, aluminum tris (acetylacetate), aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetate), alkylacetylacetate aluminum diisopropylate Etc.

The use of a tertiary amine compound having no active hydrogen group is preferable because it is non-tin and excellent film properties can be obtained.

Examples of the tertiary amine compound having no active hydrogen group include trialkylamines such as triethylamine, triethylenediamine, and trimethylamine, tetramethylenediamine, N, N, N ′, N′-tetramethyl-1,3- Tetraalkyldiamines such as butanediamine, esteramines such as bis (diethylethanolamine) adipate, cyclohexylamine derivatives such as N, N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine, N, N ′ -Piperazine derivatives such as diethyl-2-methylpiperazine can be mentioned. From the viewpoint of curing activity, a cyclic amine compound is preferable, and triethylenediamine is particularly preferable.

These curing catalysts (C) may be used alone or in combination of two or more.

The amount of the curing catalyst (C) used may be appropriately adjusted depending on the curing temperature and time, but is 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer (A). It is preferable that the amount is 0.1 to 5 parts by weight. When the amount is less than 0.01 part by weight, the reactivity of the hydrolyzable silyl group tends to be insufficient and the balance of the coating film performance tends to be inferior. When the amount exceeds 20 parts by weight, the pot life is shortened and the workability is inferior. There is a tendency.

(Curable resin composition)
The curable resin composition of the present invention may contain, for example, the following components as necessary in addition to the components (A) to (C).
In this system, it is preferable not to contain a polybutadiene-based polymer because the appearance and surface hardness may be decreased, and further, the contamination resistance may be decreased.

(solvent)
There is no particular limitation on the solvent used in the multi-component curable resin composition containing the vinyl copolymer (A), and known aromatic, aliphatic hydrocarbon, ether, ketone, ester, Alcohol-based solvents such as water can be used. From the viewpoint of the solubility of the vinyl copolymer (A), it is preferable to use an ester type such as toluene, xylene or butyl acetate, a ketone type such as methyl isobutyl ketone, or an aliphatic hydrocarbon-containing solvent.
In consideration of the appearance of the coating film during curing, it is desirable to adjust the volatilization rate by mixing other solvents.

(Dehydrating agent)
Since the vinyl copolymer (A) having a hydrolyzable silyl group and a hydroxyl group has reactivity with moisture, the storage stability of the composition can be improved by further adding a dehydrating agent. .

Examples of the dehydrating agent include alkyl orthoformate such as methyl orthoformate, ethyl orthoformate or butyl orthoformate; alkyl orthoacetate such as methyl orthoacetate, ethyl orthoacetate or butyl orthoacetate; methyl orthoborate, ethyl orthoborate, ortho Examples thereof include orthocarboxylic acid esters such as alkyl orthoborate such as butyl borate, and highly active silane compounds such as tetramethoxysilane, tetraethoxysilane, and methyltrimethoxysilane.

The amount of the dehydrating agent used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the vinyl copolymer (A).

(Other)
An additive can be mix | blended with the multi-component curable resin composition for coating of this invention as needed. Examples of the additive include a plasticizer, a dispersant, a dehydrating agent, a wetting agent, a thickening agent, an antifoaming agent, a preservative, an anti-settling agent, a leveling agent, an ultraviolet absorber, and a light stabilizer.

Further, a pigment may be added as necessary. Examples of the pigment include white pigments such as titanium dioxide, calcium carbonate, barium carbonate, and kaolin, and colored pigments such as carbon black, bengara, and cyanine blue.

The method for preparing the curable resin composition of the present invention is not particularly limited as long as the curable resin composition is multi-component. In consideration of the mixing ratio of the composition, storage stability, mixing method, pot life and the like, the compounding components are mixed in multiple liquids and mixed at the time of use. That is, in the case of the two-pack type, the blending component is divided into two liquids, liquid A and liquid B, and the liquids are mixed at the time of use. The method of dividing the liquid A and the liquid B can be variously combined depending on the storage stability and the like. Moreover, it is also possible to divide into three liquid type or more if necessary.

As described above, the multi-component curable resin composition for coating according to the present invention is obtained. When applying the multi-component curable resin composition for coating of the present invention, a roll coater method, a blade coater method, a gravure coater method, a beat coater method, a curtain flow coater method, a dip coating method, and a spray coating method. Either is possible.

(Curing method)
Moreover, the curable resin composition can be cured at an arbitrary temperature ranging from room temperature to 300 ° C.
When the curable resin composition is a thermosetting type, the heating time can be shortened as the heating temperature increases. In that case, it is preferable to heat cure at a temperature of 65 to 250 ° C. for 5 seconds to 60 minutes.
Of course, it is possible to form a coating film under mild curing conditions even for materials that cannot be heated excessively. In that case, it is preferable to cure by moisture at about room temperature.

(Coating)
As thickness of the coating film of the curable resin composition for multi-component coatings of this invention, 0.5-70 micrometers is preferable and 5-50 micrometers is more preferable. If it is too thin, the coating film is likely to be damaged due to physical wear, which is not preferable in terms of durability, and if it is too thick, the coating film may be cracked and peeled off when the coating material is processed. It becomes easy and is not preferable.

Examples of the coated object of the multi-component curable resin composition for coating according to the present invention include metals, inorganic substances, organic substances, and composite materials. Examples of the metal include stainless steel, aluminum, tinplate, tin, mild steel plate, copper, brass, various plated steel plates, and titanium. A substrate subjected to a surface treatment such as a chemical conversion treatment or an alumite treatment can also be suitably used. Examples of the inorganic material include glass, mortar, slate, concrete and roof tile. Examples of organic substances include plastic molded products such as polypropylene, polyethylene, acrylic, polycarbonate, ABS, polystyrene, PET, nylon, polyester, rubber, and elastomer, and products obtained by processing these into films (note that these are From the viewpoint of adhesion, it may be subjected to surface treatment if necessary). Furthermore, since the present invention has a sufficient function when applied as a top coat, it can also be used for various organic undercoats such as epoxy paints, urethane paints and melamine paints. Examples of the composite material include FRP, FRTP, a laminate, and a sandwich material in which a metal and an organic material are pressure-bonded.

(Use)
Specific applications of the curable resin composition include cell phones, (personal) computer casings, plastic molded products such as home appliances, flat panel displays, touch panel films, wood products such as tables, desks, and furniture. Examples include painting on various metal products. In addition, since a coating film excellent in weather resistance, acid resistance, chemical resistance, scratch resistance, and stain resistance can be obtained, an automotive clear coating agent used as a top coat for automobiles is also cited as a preferred application.

The automotive clear coating agent according to the present invention comprises the multi-component curable resin composition for coating according to the present invention.

Moreover, the coated object which concerns on this invention is what coated the multi-component curable resin composition for coating of this invention.

Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto.

(Vinyl copolymer)
In a reactor equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas inlet tube and a dropping funnel, the components (a) in Table 1 were charged, and the temperature was raised to 110 ° C. while introducing nitrogen gas. The mixture of components a) was dropped from the dropping funnel at a constant rate over 5 hours. Next, the mixed solution of the component (c) was dropped at a constant rate over 1 hour. Then, after stirring at 110 degreeC for 2 hours continuously, it cooled to room temperature. Finally, component (D) in Table 1 was added and stirred to synthesize a copolymer.

Table 1 shows the solid content concentration of the obtained copolymer, the number average molecular weight measured by GPC, and the like. The copolymers (A-1 to A-8) were once diluted with a polymerization solvent so that the solid concentration was 50%, and proceeded to the next blending.

(Curing agent)
Curing agents (H-1 to H-7) were prepared according to the formulation shown in Table 2.

FM-4: Daicel Chemical Industries Co., Ltd. Lactone Modified Hydroxyethyl Methacrylate Coronate HX: Nippon Polyurethane Industry Co., Ltd. Polyisocyanate (NCO% = 21.3%)
Coronate 2349: Polyisocyanate manufactured by Nippon Polyurethane Industry Co., Ltd. (NCO% = 12.2%)

(Physical property evaluation 1)
A coating solution is prepared according to the formulation shown in Table 3, applied to a polycarbonate resin molded plate by an air spray coating method so that the dry film thickness is 20 to 30 μm, dried at 80 ° C. for 30 minutes, solvent resistance, and The chemical resistance was evaluated.

・ Solvent resistance, chemical resistance Polycarbonate resin molded plate test piece 3 days after curing at room temperature, spot the solvents and chemicals shown in Table 3 and in the case of solvent resistance evaluation, keep static until the solvent volatilizes at room temperature. In the case of chemical resistance evaluation, the sample was allowed to stand at 80 ° C. for 1 hour, then wiped with absorbent cotton, and the state of the coating film was observed.
○: No change Δ: Spot mark remains ×: Copatone (registered trademark) and Nivea (registered trademark) in which the coating film is swollen (dissolved) were used as follows.
Copatone: Copatone SPF50 (manufactured by Kao Corporation)
Nivea: Nivea SPF47 (manufactured by IC Corporation)

(Physical property evaluation 2)
Aqueous base coat white (AXUZ-DRY: made by Isamu Paint Co., Ltd.) is applied to the cation electrodeposition-coated zinc phosphate treated steel plate (Nippon Test Panel Co., Ltd. Valbond treated plate) and preheated at 80 ° C. for 5 minutes. Went. Next, the coating liquid prepared according to the formulation shown in Table 3 was applied by an air spray coating method so that the dry film thickness was 30 to 40 μm, and baked at 140 ° C. for 30 minutes to form a coating film, which was evaluated. It was.

-After 1 day of acid-resistant room temperature curing, a 40% sulfuric acid aqueous solution was spotted and allowed to stand at 70 ° C. for 30 minutes, and then the sulfuric acid aqueous solution was washed off with water and the state of the coating film was observed.
○: No change Δ: Spot mark remains ×: The coating film is swollen (dissolved)

Scratch resistance After 3 days of room temperature curing, using an eraser abrasion tester (manufactured by Mitsumoto Seisakusho Co., Ltd.), the steel wound # 0000 was reciprocated 30 times with a load of 250 g / cm ² , and the scratches remaining on the coating film Was observed.
○: No scratch ○ △: Several scratches Δ: Shallow scratches of several to 10 or less ×: Ten or more scratches or deep scratches / scratch repairability A scratch is applied to the coating film using a Knoop hardness tester, 30 The condition of the wound (restorability) after a minute was observed.
○: The wound has been recovered Δ: The area of the wound has decreased ×: No change −: Not implemented

-The stain-resistant prepared coated plate was placed at an angle of 30 ° outdoors in Settsu City, Osaka, and exposed. After exposure for 2 months, the degree of contamination on the coating film surface was visually observed and evaluated.
○: Not very dirty and excellent in stain resistance △: Thin stain can be confirmed ×: Clearly noticeable stain can be confirmed

In Examples 1 to 10, a well-balanced coating film having high solvent resistance, acid resistance and chemical resistance immediately after curing, and excellent scratch resistance was obtained. Furthermore, it was difficult to get dirty when used outdoors, and was excellent in stain resistance. Examples 5 and 9 using 4-hydroxybutyl acrylate, which is a monomer in which a hydroxyl group is bonded to an acryloyl group via an alkylene group having 4 carbon atoms, and a polylactone having a carbon-carbon double bond at the end In Example 7 using FM-4 which is a system monomer, in addition to solvent resistance, acid resistance, chemical resistance and scratch resistance, scratch repairability was also observed.
In addition, when the same chemical-resistance evaluation as the physical property evaluation 1 was performed also about the coating board produced in the physical property evaluation 2, the same result as the result described in Table 3 was obtained.
Also, a coating solution is prepared on an ABS resin molded plate according to the formulation shown in Table 3, and is applied by an air spray coating method so that the dry film thickness is 20 to 30 μm, dried at 80 ° C. for 30 minutes, and physical property evaluation 2 When the same scratch resistance evaluation was performed, the same results as described in Table 3 were obtained.

On the other hand, in Comparative Example 1 using a copolymer (A-6) having less than 10 hydrolyzable group silicon groups and hydroxyl groups in one molecule, sufficient chemical resistance and scratch resistance were not obtained. . Further, although there are 10 or more hydrolyzable silicon groups in one molecule, in Comparative Example 2 which does not contain a hydroxyl group, the stain resistance is excellent, but the scratch resistance is, on the contrary, there are 10 or more hydroxyl groups in one molecule. However, Comparative Example 3 containing no hydrolyzable silicon group resulted in extremely poor chemical resistance and stain resistance.

As described above, the curable resin composition for coating of the present invention exhibits high solvent resistance, acid resistance and chemical resistance, and is excellent in scratch resistance and stain resistance. It was confirmed that it was a curable resin composition for coating that could be solved in a well-balanced manner. Furthermore, it was confirmed that the use of a specific monomer as the copolymer component can also be expected to provide wound repairability.

Claims (7)

(A) The main chain is a (meth) acrylic copolymer chain, and the general formula (I):
R ² _a
｜
-Si- (OR ¹ ) _3-a (I)
Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 25 carbon atoms, and an aralkyl having 7 to 12 carbon atoms. And represents a monovalent hydrocarbon group selected from the group a represents an integer of 0 to 2.)
A vinyl-based copolymer having 10 or more hydrolyzable silicon groups represented by the formula, and having 10 or more hydroxyl groups in the main chain terminal and / or side chain,
(B) a compound containing two or more isocyanate groups, and
(C) A multi-component curable resin composition for coating, comprising a hydrolyzable silicon group and an isocyanate curing catalyst ,
The vinyl copolymer (A) is a monomer having a hydroxyl group bonded to a (meth) acryloyl group via an alkylene group having 3 or more carbon atoms and / or a polylactone system having a carbon-carbon double bond at the terminal. A multi-component curable resin composition for coating, which is obtained by copolymerizing monomers . The multi-component curable resin composition for coating according to claim 1, wherein the vinyl copolymer (A) is a polymer having a hydroxyl value of 50 to 300 mgKOH / g. The multi-component curable resin composition for coating according to claim 1 or 2, wherein the vinyl copolymer (A) has a glass transition temperature of -20 to 80 ° C. It said curing catalyst (C) is a tin compound, aluminum chelate compounds, and, according to claim 1 to 3, characterized in that at least one selected from the group consisting of tertiary amine compound having no active hydrogen group The multi-component curable resin composition for coating according to any one of the above. The multi-component curable resin composition for coating according to claim 4 , wherein the curing catalyst (C) is a cyclic amine compound. An automotive clear coating agent comprising the multi-component curable resin composition for coating according to any one of claims 1 to 5 . A coated product coated with the multi-component curable resin composition for coating according to any one of claims 1 to 5 .