JPH10147744A - Curable coating composition method for forming finish coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition which can form a coating film excellent in acid resistance, scratch resistance and staining resistance by selecting a composite crosslinkable mixture comprising a carboxyl compound, a polyepoxide, a hydroxy resin and a tris(alkoxycarbonylamino)triazine. SOLUTION: This composition comprises a carboxylic compound (A), a polyepoxide (B), a hydroxy resin (C) and a tris(alkoxycarbonylamino)triazine (D) represented by the formula (wherein R<1> , R<2> and R<3> , which are the same or different from each other, are each a 1-20C hydrocarbon group). The mixing ratio among the components is preferably such that the ratio of the carboxyl groups of A to the epoxy groups of component B is 1:2 to 1:0.7 by equivalent, the ratio of the total solid content of A and B to the solid content of C is 98:2 to 70:30 by weight, and 2-30 pts.wt. D (in terms of the solid content) is used per 100 pts.wt. total of A to B (in terms of the solid content). Component A is exemplified by an acrylic polymer or a half ester of a polyol with a 1,2-acid anhydride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel curable coating composition and a method for forming a top coat using the composition.

[0002]

2. Description of the Related Art In the past, paints for top coating such as automobile outer panels have been mainly of a type in which a hydroxyl group-containing acrylic resin is cured by heating with a melamine resin. However, in recent years, etching of a coating film and stain-like stains due to acid rain have become problems worldwide. Further, with the spread of car wash machines, abrasion caused by the car wash machines has also become a problem. For this reason, there is a demand for a topcoat paint, particularly a clear topcoat paint, which can form a coating film having both sufficient acid resistance and abrasion resistance.

[0003] The imparting of scratch resistance to a coating film is usually achieved by making the coating film highly crosslinked. On the other hand, imparting acid resistance to a coating film is usually achieved by introducing a crosslinking system resistant to acid. However, almost no method has been proposed so far to impart acid resistance to the coating film while also imparting scratch resistance.

[0004] For example, Japanese Patent Application Laid-Open No. 2-227553 discloses that an acrylic resin having a high hydroxyl value is baked in the presence of a monomeric melamine resin and an acid catalyst to form a highly crosslinked density coating film, and a high degree of scratch resistance can be obtained. Is described.
However, this crosslinked system has a drawback that the acid resistance is inferior due to the fact that the crosslinked coating film of the melamine resin is easily decomposed with an acid.

[0005] As a method for introducing another acid-resistant cross-linking system into the acid-sensitive melamine resin cross-linking system to achieve both acid resistance and scratch resistance of the coating film, carboxyl groups / epoxy groups / hydroxyl groups / Complex cross-linking system of melamine resin
No. 247264) and a complex crosslinking system of a hydroxyl group / alkoxysilyl group / melamine resin (JP-A-4-816383).
Nos. 1 and 2, but the improvement in acid resistance was not always sufficient due to the use of a melamine resin.

On the other hand, as a cross-linking system using no melamine resin, a cross-linking system consisting of only a carboxyl group / epoxy group or a carboxyl group / epoxy group / hydroxyl group (JP-A-62-87288, JP-A-2-4557)
No. 7, JP-A-3-287650), these systems are excellent in acid resistance of the coating film, but have insufficient scuff resistance because the cured coating does not have a high crosslinking density. There is a disadvantage that there is.

Also, a resin composition comprising a carboxyl group-containing vinyl polymer and a compound containing an epoxy group and a hydrolyzable silyl group, which is a cross-linking system combining a carboxyl group / epoxy group / hydrolyzable silyl group (particularly, Kaihei 6
However, the curing reaction between the polymer and the compound becomes insufficient due to steric hindrance caused by the presence of an epoxy group and a hydrolyzable silyl group in the same molecule. There are drawbacks.

Further, a silicone polymer having a hydroxyl group and a carboxyl group, a polymer having a carboxyl group and a carboxylic ester group, wherein a silicone polymer is used as a base resin in a carboxyl group / epoxy group / hydroxyl group crosslinking system. And a resin composition comprising a polymer having a hydroxyl group and an epoxy group has been proposed (Japanese Patent Laid-Open No. 6-1).
No. 66741) has the disadvantage that the crosslinked density of the cured coating film is not always sufficient, and that it is inferior in recoat adhesion, which is an important property when used as a coating for automobile outer panels.

[0009] Further, the above-mentioned cross-linking system not using a melamine resin has a problem in that it cannot always be said that organic matter pollution resistance such as pollen resistance and bird dropping resistance and city-type pollution resistance such as diesel soot are good. There is.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel curable coating composition which has solved the above-mentioned disadvantages of the prior art, and a method for forming a top coat using the composition.

Another object of the present invention is to provide a novel curable coating composition capable of forming a coating film having both excellent acid resistance and abrasion resistance at the same time, and a method for forming a topcoat film using the composition. is there.

Another object of the present invention is to provide a novel curable coating composition having excellent low-temperature curability, storage stability and recoat adhesion, and a method for forming a top coat using the composition.

It is another object of the present invention to provide a novel curable coating composition having excellent resistance to organic matter contamination and urban-type contamination, and a method for forming a top coat using the composition.

[0014] These and further objects of the present invention will become apparent from the following description.

[0015]

According to the present invention, there are provided (A) a carboxyl group-containing compound, (B) a polyepoxide, (C) a hydroxyl group-containing resin, and (D) a compound represented by the general formula:

[0016]

Embedded image

Wherein R ¹ , R ² and R ³ are the same or different and each represent a hydrocarbon group having 1 to 20 carbon atoms. ]
The present invention provides a curable coating composition containing tris (alkoxycarbonylamino) triazine represented by the following formula (hereinafter referred to as “paint composition (1)”).

The present invention also includes (A) a carboxyl group-containing compound, (E) a resin containing an epoxy group and a hydroxyl group, and (D) tris (alkoxycarbonylamino) triazine of the above general formula [1]. A curable coating composition (hereinafter referred to as "coating composition (2)"), (F) a resin containing a carboxyl group and a hydroxyl group, (B) a polyepoxide, and (D) A curable coating composition containing tris (alkoxycarbonylamino) triazine represented by the above general formula [1] (hereinafter referred to as “paint composition (3)”).
).

Further, the present invention relates to a method for forming a top coat by sequentially forming a colored base coat and a clear top coat on an object, wherein the paint for forming the colored base coat and / or the clear top coat is any one of the above-mentioned paints. Another object of the present invention is to provide a method for forming an overcoat film, wherein the method is a single coating composition.

The present inventors have conducted intensive studies to achieve the above object. As a result, they have found that the above objects can be achieved by using a composite cross-linking system composed of a carboxyl group / epoxy group / hydroxyl group / tris (alkoxycarbonylamino) triazine, thereby completing the present invention.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the curable coating composition and the method for forming an overcoat film of the present invention will be described in more detail.

Coating Composition (1) The coating composition (1) comprises (A) a carboxyl group-containing compound, (B) a polyepoxide, (C) a hydroxyl group-containing resin, and (D) tris (alkoxycarbonylamino) triazine. It is a composition contained as an essential component.

Carboxyl group-containing compound (A) The compound (A) is a compound having a carboxyl group in one molecule and usually has an acid value of 50 to 500 mgKOH /
g, preferably 80 to 300 mg KOH / g.

The compound (A) has an acid value of 50 mgKOH / g
If the acid value is less than 500 mgKOH / g, the curability of the resulting composition tends to decrease, and the acid resistance, abrasion resistance and stain resistance of the coating film tend to decrease. ), The compatibility with the hydroxyl group-containing resin (C) and the tris (alkoxycarbonylamino) triazine (D) tends to decrease, and storage stability tends to be impaired. Examples of the compound (A) include the following (A-1) to (A-4).

(A-1): Half-esterification of an acid anhydride group
The vinyl polymer compound (A-1) having a group formed by the above is a vinyl polymer resin having a group obtained by half-esterifying an acid anhydride group in one molecule. Here, the group obtained by half-esterifying an acid anhydride group means a group obtained by adding a fatty monoalcohol to an acid anhydride group to open a ring (that is, half-esterifying) to obtain a carboxyl group and a carboxylic acid ester group. Means the group Hereinafter, this group may be simply referred to as a half ester group.

Compound (A-1) comprises a vinyl monomer having a half ester group and another vinyl monomer,
It can be easily obtained by copolymerization according to a conventional method. Further, it can also be easily obtained by similarly copolymerizing a vinyl monomer having an acid anhydride group instead of the vinyl monomer having a half ester group, and then half-esterifying the acid anhydride group.

Examples of the vinyl monomer having an acid anhydride group include those having maleic anhydride, itaconic anhydride and the like. Examples of the vinyl monomer having a half ester group include those obtained by half esterifying the acid anhydride group of the vinyl monomer having the acid anhydride group.

As described above, the half esterification may be performed either before or after the copolymerization reaction. As the aliphatic monoalcohol used for the half esterification, low molecular weight monoalcohols, for example, methanol, ethanol,
Isopropanol, tert-butanol, isobutanol, methyl cellosolve, ethyl cellosolve and the like. The half-esterification reaction can be carried out according to a usual method, usually at a temperature from room temperature to about 80 ° C., using a tertiary amine as a catalyst if necessary.

Other vinyl monomers include, for example, vinyl monomers having a hydroxyl group; (meth) acrylates; vinyl ethers and aryl ethers;
Olefinic compounds and diene compounds; hydrocarbon ring-containing unsaturated monomers; nitrogen-containing unsaturated monomers, and the like.

Examples of the vinyl monomer having a hydroxyl group include:
For example, 2-hydroxyethyl (meth) acrylate,
C2-C8 hydroxyalkyl esters of acrylic acid or methacrylic acid, such as 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate; polyethylene glycol, polypropylene glycol, polybutylene Monoester of polyether polyol such as glycol and unsaturated carboxylic acid such as (meth) acrylic acid; polyether polyol such as polyethylene glycol, polypropylene glycol, polybutylene glycol and hydroxyl group containing such as 2-hydroxyethyl (meth) acrylate Monoethers with unsaturated monomers; unsaturated compounds containing acid anhydride groups such as maleic anhydride and itaconic anhydride; ethylene glycol, 1,6-hexanediol, neopentyl Monoesters or diesters with glycols such as coal; hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether; allyl alcohol and the like; α, β-unsaturated carboxylic acid and Cardura E10 (manufactured by Shell Petrochemical Co., Ltd.) Adducts of glycidyl (meth) acrylate with monobasic acids such as acetic acid, propionic acid, p-tert-butylbenzoic acid and fatty acids; An adduct of the above hydroxyl-containing monomer with a lactone (eg, ε-caprolactone, γ-valerolactone), and the like.

Examples of (meth) acrylates include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, stearyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n methacrylate -Butyl, isobutyl methacrylate, tert-butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate,
C1-24 alkyl or cycloalkyl esters of acrylic acid or methacrylic acid such as stearyl methacrylate and cyclohexyl methacrylate; methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate,
Examples thereof include alkoxyalkyl esters of acrylic acid or methacrylic acid having 2 to 18 carbon atoms, such as ethoxybutyl acrylate and ethoxybutyl methacrylate.

Examples of the vinyl ethers and aryl ethers include chain alkyl vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, tert-butyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether and octyl vinyl ether; cyclopentyl vinyl ether; Cycloalkyl vinyl ethers such as cyclohexyl vinyl ether; aryl vinyl ethers such as phenyl vinyl ether and trivinyl ether; aralkyl vinyl ethers such as benzyl vinyl ether and phenethyl vinyl ether; allyl ethers such as allyl glycidyl ether and allyl ethyl ether.

Examples of the olefinic compound and the diene compound include ethylene, propylene, butylene, vinyl chloride, butadiene, isoprene, chloroprene and the like.

Examples of the unsaturated monomer having a hydrocarbon ring include styrene, α-methylstyrene, phenyl (meth) acrylate, phenylethyl (meth) acrylate, phenylpropyl (meth) acrylate, benzyl (meth) acrylate, Phenoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-
Acryloyloxyethyl hydrogen phthalate, 2
-Acryloyloxypropyl hydrogen phthalate, 2-acryloyloxypropyl hexahydrohydrogen phthalate, 2-acryloyloxypropyl tetrahydrohydrogen phthalate, esterified product of p-tert-butyl-benzoic acid and hydroxyethyl (meth) acrylate, dicyclopentenyl (Meth) acrylate and the like.

Examples of the nitrogen-containing unsaturated monomer include, for example,
N, N-dimethylaminoethyl (meth) acrylate,
N, N-diethylaminoethyl (meth) acrylate,
Nitrogen-containing alkyl (meth) acrylates such as Nt-butylaminoethyl (meth) acrylate; acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) Polymerizable amides such as acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide; 2-vinylpyridine, 1-vinyl-2-pyrrolidone, 4-vinylpyridine and the like Aromatic nitrogen-containing monomers; polymerizable nitriles such as acrylonitrile and methacrylonitrile; allylamine.

As the copolymerization method, a general polymerization method of a vinyl monomer can be used, but in consideration of versatility and cost, a solution type radical polymerization method in an organic solvent is most suitable. That is, aromatic solvents such as xylene and toluene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate and 3-methoxybutyl acetate; n-butanol and isopropyl alcohol By performing a copolymerization reaction in the range of about 60 to 150 ° C. in the presence of a polymerization initiator such as azobisisobutyronitrile and benzoyl peroxide in a solvent such as an alcohol solvent, the desired polymer can be easily obtained. Can be obtained.

The copolymerization amount of each of the vinyl monomer having a half ester group or an acid anhydride group and the other vinyl monomer is usually appropriate to be as follows in all the monomers. That is, from the viewpoint of curability and storage stability, the vinyl monomer having a half ester group or an acid anhydride group is about 5 to 40% by weight, preferably 10 to 30% by weight.
% By weight. It is appropriate that the other vinyl monomer accounts for about 60 to 95% by weight, preferably 70 to 90% by weight. The amount of styrene used among the other vinyl monomers is suitably up to about 20% by weight from the viewpoint of the weather resistance of the cured coating film. still,
When a vinyl monomer having an acid anhydride group is used, half esterification after polymerization is as described above.

The compound (A-1) is preferably an acrylic polymer having a number average molecular weight of 2,000 to 20,000. If the number average molecular weight is smaller than 2,000, the weather resistance of the cured coating film tends to decrease,
If it exceeds 000, polyepoxide (B), hydroxyl-containing resin (C) and tris (alkoxycarbonylamino)
Any of these is not preferred because compatibility with the triazine (D) tends to decrease.

(A-2): carboxyl group-containing vinyl type
The polymer compound (A-2) is a vinyl polymer resin having a carboxyl group in one molecule. The compound (A-2) preferably has a number average molecular weight in the range of 2,000 to 20,000. If the number average molecular weight is less than 2,000, the weather resistance of the cured coating film tends to decrease. If it exceeds 20,000, polyepoxide (B), hydroxyl group-containing resin (C) and tris (alkoxycarbonylamino) triazine (D )) Are not preferred, since the compatibility with) tends to decrease.

The compound (A-2) can be easily obtained by copolymerizing a vinyl monomer having a carboxyl group and other vinyl monomers in the same manner as in the case of the compound (A-1). .

Examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 5-carboxypentyl (meth) acrylate and the like.

Other vinyl monomers include (meth) acrylic esters, vinyl ethers and aryl ethers, olefinic compounds and diene compounds, unsaturated monomers containing a hydrocarbon ring, and the like, as exemplified for compound (A-1). Examples thereof include a nitrogen-containing unsaturated monomer.

(A-3): carboxyl group-containing polyester
The terpolymer compound (A-3) is a carboxyl group-containing polyester polymer resin.

The number average molecular weight of the carboxyl group-containing polyester polymer to be used is not particularly limited, but it is usually appropriate that the number average molecular weight is about 1,500 to 2,000.

The carboxyl group-containing polyester polymer includes ethylene glycol, butylene glycol, 1,6
-Can be easily obtained by a condensation reaction between a polyhydric alcohol such as hexanediol, trimethylolpropane, and pentaerythritol and a polycarboxylic acid such as adipic acid, terephthalic acid, isophthalic acid, phthalic anhydride, and hexahydrophthalic anhydride. it can. For example, a carboxyl group-containing polyester polymer can be obtained by a one-step reaction under the compounding condition of polycarboxylic acid with excess carboxyl group. After synthesizing the polyester polymer of the above, a carboxyl group-containing polyester polymer can also be obtained by post-adding an acid anhydride group-containing compound such as phthalic anhydride, hexahydrophthalic anhydride and succinic anhydride.

(A-4): Polyol and 1,2-acid anhydride
The half ester compound (A-4) formed by the addition reaction with a product is a half ester formed by the reaction between a polyol and a 1,2-acid anhydride, and the number average molecular weight thereof is not particularly limited. 400-1,0
Since it has a low molecular weight of about 00 and has high reactivity with epoxy groups, it is useful for forming a high solid content coating composition.

The half ester is composed of a polyol and 1,2-
It is obtained by reacting with an acid anhydride under conditions sufficient for a ring-opening reaction of the acid anhydride to occur and for substantially no polyesterification reaction to occur. Such reaction products have a low molecular weight and a narrow molecular weight distribution. They also exhibit a low volatile organic content in the composition and impart excellent properties in the resulting coating.

The half-esterification was carried out with a polyol and 1,2
-Acid anhydride with an inert atmosphere, for example under a nitrogen atmosphere,
It is performed in the presence of a solvent. Examples of suitable solvents include, for example, ketones such as methyl amyl ketone, diisobutyl ketone, methyl isobutyl ketone; aromatic hydrocarbons such as toluene and xylene; or other organic solvents such as dimethylformamide and N-methylpyrrolidone. Is mentioned.

The reaction temperature is preferably as low as about 150 ° C. or less. Specifically, it is usually preferably about 70 to 150C, more preferably about 90 to 120C. 150 ° C
If the temperature exceeds, the polyesterification reaction occurs, which is not desirable. If the temperature is lower than 70 ° C., a sufficient reaction rate cannot be obtained, which is not preferable.

The reaction time basically varies somewhat depending on the reaction temperature, but is usually about 10 minutes to 24 hours.

The equivalent ratio of acid anhydride to polyol is about 0.8: 1 to 1.2: 1, calculated assuming that the acid anhydride is monofunctional.
Within the range, the desired half ester can be obtained to the maximum.

The acid anhydride used for preparing the desired half ester has about 2 to 2 carbon atoms except for the carbon atom in the acid portion.
30. Examples of such include aliphatic, cycloaliphatic, olefinic and cyclic olefinic anhydrides and aromatic anhydrides. Substituted aliphatic and substituted aromatic anhydrides are included in the aliphatic and aromatic anhydrides as long as the substituents do not adversely affect the reactivity of the anhydride or the properties of the obtained half ester. It is. Examples of substituents include chloro, alkyl and alkoxy groups. Examples of acid anhydrides include succinic anhydride, methyl succinic anhydride, dodecenyl succinic anhydride, octadecenyl succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexa Hydrophthalic anhydride,
Alkyl hexahydrophthalic anhydride (eg, methyl hexahydrophthalic anhydride), tetrafluorophthalic anhydride, endomethylene tetrahydrophthalic anhydride,
Chlorendic anhydride, itaconic anhydride, citraconic anhydride and maleic anhydride.

The polyols that can be used are those having about 2 to 20 carbon atoms.
It has. Preferably, diols, triols and mixtures thereof are used. Examples of such include polyols having 2 to 20 carbon atoms. Examples of suitable are aliphatic polyols,
For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, glycerol,
2,3-butanetriol, 1,6-hexanediol, neopentyl glycol, diethylene glycol,
Dipropylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, trimethylolpropane, 2,2,4-trimethylpentane-1,3-diol, pentaerythritol and 1,2,3 , 4-butanetetraol. Aromatic polyols such as bisphenol A and bis (hydroxymethyl) xylene may be used.

Polyepoxide (B) Polyepoxide (B) is a resin having an epoxy group in one molecule and usually has an epoxy group content of 0.8 to 15%.
Mmol / g, preferably 1.2 to 10 mmol / g.

When the epoxy group content of the polyepoxide (B) is less than 0.8 mmol / g, the curability of the resulting composition is reduced, and the acid resistance, scratch resistance and stain resistance of the coating film are reduced. When the epoxy group content exceeds 15 mmol / g, the compatibility with the carboxyl group-containing compound (A), the hydroxyl group-containing resin (C) and the tris (alkoxycarbonylamino) triazine (D) decreases. And storage stability tends to be impaired,
Neither is preferred.

Specific examples of the polyepoxide (B) include:
For example, epoxy group-containing acrylic polymers; glycidyl ether compounds such as diglycidyl ether, 2-glycidylphenyl glycidyl ether and 2,6-diglycidylphenyl glycidyl ether; glycidyl groups such as vinylcyclohexene dioxide and lemonon dioxide; Cyclic epoxy group-containing compound; dicyclopentadienedioxide, bis (2,3-epoxycyclopentyl) ether, epoxycyclohexene carboxylic acid ethylene glycol diester, bis (3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexyl Methyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarbo Alicyclic epoxy group-containing compounds and the like such as Shireto, which are also possible to use a mixture of course.

Of these, the number average molecular weight is from 2,000 to
20,000 epoxy group-containing acrylic polymers are preferably used. When the number average molecular weight is less than 2,000, the weather resistance of the cured coating film tends to decrease, and
(A), hydroxyl-containing resin (C) and tris (alkoxycarbonylamino) triazine (D)
Both are not preferred, since the compatibility with the polymer tends to decrease.

The epoxy group-containing acrylic polymer can be easily obtained by copolymerizing a vinyl monomer having an epoxy group and other vinyl monomers in the same manner as in the case of the compound (A-1). Can be.

Examples of the vinyl monomer having an epoxy group include glycidyl (meth) acrylate and allyl glycidyl ether.

Other vinyl monomers include those having a hydroxyl group as exemplified in the above-mentioned compound (A-1), (meth) acrylates, vinyl ethers and aryl ethers, olefinic compounds and diene compounds, and hydrocarbon ring-containing compounds. In addition to unsaturated monomers and nitrogen-containing unsaturated monomers, vinyl monomers having a hydrolyzable alkoxysilyl group can be exemplified.

Examples of the vinyl monomer having a hydrolyzable alkoxysilyl group include, for example, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (Meth) acryloyloxypropyltrimethoxysilane, γ-
(Meth) acryloyloxypropylmethyldimethoxysilane, vinyltriacetoxysilane, β- (meth) acryloyloxyethyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane,
γ- (meth) acryloyloxypropylmethyldiethoxysilane and the like, preferably vinyltriethoxysilane in which the hydrolyzable alkoxysilyl group is an ethoxysilyl group from the viewpoint of low-temperature curability and storage stability; Vinylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ-
(Meth) acryloyloxypropylmethyldiethoxysilane and the like can be mentioned.

The content of the hydrolyzable alkoxysilyl group in the epoxy group-containing acrylic polymer is usually from 0.3 to 0.3.
It is 5 mmol / g, preferably 0.5 to 3 mmol / g. When the content of the hydrolyzable alkoxysilyl group is less than 0.3 mmol / g, the curability of the resulting composition tends to decrease, and the acid resistance, scratch resistance and stain resistance of the coating film tend to decrease. If the content of the hydrolyzable alkoxysilyl group is more than 5 mmol / g, the cost increases, and neither is preferred.

Hydroxyl-containing resin (C) The hydroxyl-containing resin (C) is a resin having a hydroxyl group in one molecule, and usually has a hydroxyl value of 5 to 200 mgKOH /
g, preferably 30 to 150 mg KOH / g.

The hydroxyl value of the hydroxyl group-containing resin (C) is 5 mg.
If it is lower than KOH / g, the curability of the obtained composition tends to decrease, and the acid resistance, scratch resistance and stain resistance of the coating film tend to decrease, and the hydroxyl value is 200 mgKOH / g.
If the value is larger than g, the water resistance of the coating film tends to decrease, and thus both are not preferred.

Specific examples of the hydroxyl group-containing resin (C) include:
For example, acrylic polyols, polyester polyols, polyether polyols, polyurethane polyols and the like can be mentioned, and of course, these can be used in combination.

Of these, the number average molecular weight is from 2,000 to
20,000 hydroxyl group-containing acrylic polymers are preferably used. If the number average molecular weight is less than 2,000, the weather resistance of the cured coating film tends to decrease, and if it exceeds 20,000, compound (A), polyepoxide (B) and tris (alkoxycarbonylamino) triazine (D) Are not preferred, since the compatibility of the compounds tends to decrease.

The hydroxyl group-containing acrylic polymer can be easily obtained by copolymerizing a vinyl monomer having a hydroxyl group and another vinyl monomer in the same manner as in the case of the compound (A-1). .

Examples of the vinyl monomer having a hydroxyl group include:
Examples of the compound (A-1) can be given.

Other vinyl monomers include (meth) acrylic esters, vinyl ethers and aryl ethers, olefinic compounds and diene compounds, unsaturated monomers containing a hydrocarbon ring, and the like. In addition to the nitrogen-containing unsaturated monomer, a vinyl monomer having a hydrolyzable alkoxysilyl group can be exemplified.
Examples of the vinyl monomer having a hydrolyzable alkoxysilyl group include the monomers exemplified for the polyepoxide (B). From the viewpoint of low-temperature curability and storage stability, the hydrolyzable alkoxysilyl group is preferably an ethoxy group. Examples of the silyl group include vinyltriethoxysilane, vinylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, and γ- (meth) acryloyloxypropylmethyldiethoxysilane. The content of the hydrolyzable alkoxysilyl group in the hydroxyl group-containing acrylic polymer is usually 0.1.
3-5 mmol / g, preferably 0.5-3 mmol / g
g. When the content of the hydrolyzable alkoxysilyl group is 0.
When the amount is less than 3 mmol / g, the curability of the obtained composition tends to decrease, and the acid resistance, scratch resistance and stain resistance of the coating film tend to decrease, and the content of the hydrolyzable alkoxysilyl group tends to decrease. If the amount is more than 5 mmol / g, the cost increases, and neither is preferable.

Tris (alkoxycarbonylamino)
Liazine (D) tris (alkoxycarbonylamino) triazine (D) has the general formula

[0071]

Embedded image

Wherein R ¹ , R ² and R ³ are as defined above. ] It is a compound represented by these.

The hydrocarbon groups represented by R ^{1 to} R ³ in the above general formula include, for example, methyl, ethyl,
n-propyl, iso-propyl, n-butyl, iso
-Butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl,
alkyl groups such as n-octyl, n-nonyl, n-decanyl, n-dodecanyl and n-undecanyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; cycloalkylalkyl groups such as cyclohexylmethyl and cyclohexylethyl; phenyl, biphenyl and alkyl Aryl groups such as substituted phenyl and naphthyl; and aralkyl groups such as benzyl and phenethyl.

The above tris (alkoxycarbonylamino) triazine compounds are known per se (for example, see JP-A-5-239038).
What is marketed by the trade name of "TACT" (product of Cytec Corporation) can be used.

The mixing ratio of the carboxyl group-containing compound (A), the polyepoxide (B), the hydroxyl group-containing resin (C) and the tris (alkoxycarbonylamino) triazine (D), which are the essential components in the coating composition (1), is as follows. The mixing ratio of (A) and polyepoxide (B) is a ratio of 1: 2 to 1: 0.7 in equivalent ratio of the carboxyl group of compound (A) to the epoxy group of polyepoxide (B), and the resin ( The compounding ratio of C) is such that the weight ratio of the total solid content of the compound (A) and the polyepoxide (B) to the solid content of the resin (C) falls within the range of 98/2 to 70/30. The compounding ratio of (D) is preferably 2 to 30 parts by weight in terms of solids with respect to 100 parts by weight of the total solids of compound (A), polyepoxide (B) and resin (C). If the mixing ratio is outside the above range, the curability is lowered and the acid resistance, abrasion resistance and stain resistance of the coating film tend to be lowered, which is not preferable.

More preferably, the compounding ratio of the compound (A) to the polyepoxide (B) is 1: 1.5 to 1 in the equivalent ratio of the carboxyl group of the compound (A) to the epoxy group of the polyepoxide (B). And the mixing ratio of the resin (C) is 95/5 to 80/20 in weight ratio of the total solid content of the compound (A) and the polyepoxide (B) to the solid content of the resin (C). Wherein the compounding ratio of the compound (D) is 3 to 15 parts by weight in terms of solids with respect to 100 parts by weight of the total solids of the compound (A), the polyepoxide (B) and the resin (C). It is the ratio that becomes.

Coating Composition (2) The coating composition (2) must contain (A) a carboxyl group-containing compound, (E) a resin containing an epoxy group and a hydroxyl group, and (D) tris (alkoxycarbonylamino) triazine. It is a composition contained as a component.

The (A) carboxyl group-containing compound and (D) tris (alkoxycarbonylamino) triazine in the coating composition (2) are the same as those described in the coating composition (1).

Resin containing epoxy group and hydroxyl group
(E) The resin (E) is a resin containing an epoxy group and a hydroxyl group in one molecule, and usually has an epoxy group content of 0.5 to
5 mmol / g, preferably 0.8-2.5 mmol / g
g, hydroxyl value is 5 to 200 mgKOH / g, preferably 30 to 120 mgKOH / g.

The epoxy group content of the resin (E) is 0.5
When the amount is less than mmol / g, the curability of the resulting composition tends to decrease, and the acid resistance, abrasion resistance and stain resistance of the coating film tend to decrease, and the epoxy group content is less than 5 mmol / g. Is too large, the compatibility with the carboxyl group-containing compound (A) and the tris (alkoxycarbonylamino) triazine (D) tends to decrease, and the storage stability tends to be impaired.

The resin (E) has a hydroxyl value of 5 mgKOH /
g, the curability of the resulting composition is reduced, and the acid resistance, abrasion resistance, and stain resistance of the coating film tend to be reduced. When the hydroxyl value is larger than 200 mgKOH / g, the coating film is hardened. Since the water resistance of
Neither is preferred.

Specific examples of the resin (E) include, for example,
Acrylic resin containing epoxy group and hydroxyl group in one molecule, polyester resin containing epoxy group and hydroxyl group in one molecule, polyether resin containing epoxy group and hydroxyl group in one molecule, epoxy group and Examples thereof include a polyurethane resin containing a hydroxyl group, and of course, these can be used as a mixture.

Of these, the number average molecular weight is 2,000 to
20,000 epoxy- and hydroxyl-containing acrylic polymers are preferably used. If the number average molecular weight is less than 2,000, the weather resistance of the cured coating film tends to decrease,
If it exceeds 000, the compatibility with the compound (A) and tris (alkoxycarbonylamino) triazine (D) tends to decrease, and neither is preferred.

The acrylic polymer having an epoxy group and a hydroxyl group may be a vinyl monomer having an epoxy group, a vinyl monomer having a hydroxyl group and other vinyl monomers.
The compound (A-1) can be easily obtained by copolymerization in the same manner as in the case of the compound (A-1).

Examples of the vinyl monomer having an epoxy group include glycidyl (meth) acrylate and allyl glycidyl ether.

The vinyl monomer having a hydroxyl group includes:
Examples of the compound (A-1) can be given.

As other vinyl monomers, (meth) acrylates, vinyl ethers and aryl ethers, olefinic compounds and diene compounds, unsaturated monomers containing a hydrocarbon ring, In addition to the nitrogen-containing unsaturated monomer, a vinyl monomer having a hydrolyzable alkoxysilyl group can be exemplified.
Examples of the vinyl monomer having a hydrolyzable alkoxysilyl group include the monomers exemplified for the polyepoxide (B). From the viewpoint of low-temperature curability and storage stability, the hydrolyzable alkoxysilyl group is preferably an ethoxy group. Examples of the silyl group include vinyltriethoxysilane, vinylmethyldiethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, and γ- (meth) acryloyloxypropylmethyldiethoxysilane. The content of the hydrolyzable alkoxysilyl group in the hydroxyl group-containing acrylic polymer is usually 0.1.
3-5 mmol / g, preferably 0.5-3 mmol / g
g is desirable. When the content of the hydrolyzable alkoxysilyl group is less than 0.3 mmol / g, the curability of the resulting composition tends to decrease, and the acid resistance, scratch resistance and stain resistance of the coating film tend to decrease. If the content of the hydrolyzable alkoxysilyl group is more than 5 mmol / g, the cost increases, and neither is preferred.

In the coating composition (2), the compounding ratio of the carboxyl group-containing compound (A), the resin (E) containing an epoxy group and a hydroxyl group, and the tris (alkoxycarbonylamino) triazine (D), which are essential components, are as follows: The compounding ratio of the compound (A) and the resin (E) is 1: 1 in the equivalent ratio of the carboxyl group of the compound (A) to the epoxy group of the resin (E).
2-1: 0.7, and the compounding ratio of the compound (D) is 10 (total solid content of the compound (A) and the resin (E)).
The solid content is preferably 2 to 30 parts by weight with respect to 0 parts by weight. If the mixing ratio is outside the above range, the curability is lowered and the acid resistance, abrasion resistance and stain resistance of the coating film tend to be lowered, which is not preferable.

More preferably, the compounding ratio of the compound (A) to the resin (E) is from 1: 1.5 to 1.5 in the equivalent ratio of the carboxyl group of the compound (A) to the epoxy group of the resin (E).
The ratio is 1: 1. The compounding ratio of the compound (D) is 3 to 15 parts by weight in terms of solids based on 100 parts by weight of the total solids of the compound (A) and the resin (E).

Coating composition (3) The coating composition (3) contains (F) a resin containing a carboxyl group and a hydroxyl group, (B) a polyepoxide and (D) tris (alkoxycarbonylamino) triazine as essential components. Composition.

The (B) polyepoxide and (D) tris (alkoxycarbonylamino) triazine in the coating composition (3) are the same as those described for the coating composition (1).

Resin containing carboxyl group and hydroxyl group
(F) The resin (F) is a resin containing a carboxyl group and a hydroxyl group in one molecule, and usually has an acid value of 30 to 240 mg.
KOH / g, preferably 50-120 mg KOH / g,
The hydroxyl value is 5 to 200 mgKOH / g, preferably 30
~ 120 mgKOH / g.

The acid value of the resin (F) is 30 mgKOH / g
If the acid value is less than 240 mgKOH / g, the curability of the resulting composition tends to decrease, and the acid resistance, scratch resistance and stain resistance of the coating film tend to decrease. ) And tris (alkoxycarbonylamino) triazine (D) tend to decrease in compatibility with storage stability, and neither is preferred.

The resin (F) has a hydroxyl value of 5 mgKOH /
g, the curability of the resulting composition is reduced, and the acid resistance, abrasion resistance, and stain resistance of the coating film tend to be reduced. When the hydroxyl value is larger than 200 mgKOH / g, the coating film is hardened. Since the water resistance of
Neither is preferred.

Specific examples of the resin (F) include, for example,
Acrylic resin containing carboxyl group and hydroxyl group in one molecule, polyester resin containing carboxyl group and hydroxyl group in one molecule, polyether resin containing carboxyl group and hydroxyl group in one molecule, carboxyl group in one molecule Examples thereof include a polyurethane resin containing a hydroxyl group, and of course, these can be used as a mixture.

Of these, the number average molecular weight is from 2,000 to
A 20,000 carboxyl group- and hydroxyl group-containing acrylic polymer is preferably used. Number average molecular weight of 2,000
If it is less than 0, the weather resistance of the cured coating film tends to decrease, and if it exceeds 20,000, the compatibility with the polyepoxide (B) and tris (alkoxycarbonylamino) triazine (D) tends to decrease. Neither is preferred.

The carboxyl group- and hydroxyl group-containing acrylic polymer is obtained by using at least one vinyl monomer selected from a vinyl monomer having a half ester group, a vinyl monomer having an acid anhydride group and a vinyl monomer having a carboxyl group, and a hydroxyl group. It can be easily obtained by copolymerizing the vinyl monomer and other vinyl monomers in the same manner as in the case of the compound (A-1).

Examples of the vinyl monomer having a half ester group and the vinyl monomer having an acid anhydride group include those exemplified for the compound (A-1).

Examples of the vinyl monomer having a carboxyl group include those exemplified for the compound (A-2).

The vinyl monomer having a hydroxyl group includes:
Examples of the compound (A-1) can be given.

Other vinyl monomers include (meth) acrylic esters, vinyl ethers and aryl ethers, olefinic compounds and diene compounds, unsaturated monomers containing a hydrocarbon ring, and the like. Examples thereof include a nitrogen-containing unsaturated monomer.

The mixing ratio of the resin (F) containing carboxyl group and hydroxyl group, polyepoxide (B) and tris (alkoxycarbonylamino) triazine (D), which are essential components in the coating composition (3), is as follows. And the polyepoxide (B) in a ratio of 1: 2 to 1: 0.7 in terms of the equivalent ratio of the carboxyl group of the resin (F) to the epoxy group of the polyepoxide (B). The compounding ratio is 2 in solid content with respect to 100 parts by weight of the total solid content of resin (F) and polyepoxide (B).
It is preferably from 30 to 30 parts by weight. If the mixing ratio is outside the above range, the curability is lowered and the acid resistance, abrasion resistance and stain resistance of the coating film tend to be lowered, which is not preferable.

More preferably, the mixing ratio of the resin (F) and the polyepoxide (B) is 1: 1.5 to 1 in terms of the equivalent ratio of the carboxyl group of the resin (F) to the epoxy group of the polyepoxide (B). : 1 and the compounding ratio of the compound (D) is 3 in solid content with respect to 100 parts by weight of the total solid content of the resin (F) and the polyepoxide (B).
１５15 parts by weight.

The curable coating composition of the present invention may optionally contain a curing catalyst. As a curing catalyst that can be used, a catalyst effective for a crosslinking reaction between a carboxyl group and an epoxy group includes tetraethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrabutylphosphonium bromide, triphenylbenzylphosphonium chloride, and the like. Quaternary salt catalysts; and amines such as triethylamine and tributylamine. Of these, quaternary salt catalysts are preferred. further,
A mixture of the quaternary salt and a phosphate compound such as dibutylphosphoric acid in an approximately equivalent amount to the quaternary salt improves the storage stability of the paint without impairing the above-mentioned catalytic action and reduces the electric resistance of the paint. This is preferable because it is possible to prevent a decrease in spray coating adequacy.

Examples of catalysts effective for the crosslinking reaction of ethoxysilyl groups include tin catalysts such as dibutyltin dilaurate and dibutyltin diacetate; titanium catalysts such as tetrabutyl titanate; and amines such as triethylamine and tributylamine. be able to.

The above two curing catalysts can be used alone or in combination. However, it is desirable to use them together from the viewpoint of curability and scratch resistance.

The curable coating composition of the present invention may contain, if necessary, a so-called dehydrating agent such as trimethyl orthoacetate in order to suppress the deterioration of the coating due to the solvent contained and moisture present in the air. Is also possible.

The curable coating composition of the present invention may contain, if necessary, known general pigments such as coloring pigments, extender pigments and rust-preventive pigments.

Examples of the coloring pigment include quinacridone based pigments such as quinacridone red, azo based pigments such as pigment red, phthalocyanine blue, phthalocyanine green, and the like.
Organic pigments such as phthalocyanine based pigments such as perylene red; inorganic pigments such as titanium oxide and carbon black; metallic pigments such as aluminum flakes, nickel flakes, copper flakes, brass flakes, chrome flakes, pearl mica, and colored pearl mica. be able to.

The curable coating composition of the present invention may further contain, if necessary, various resins such as polyester resins, alkyd resins, silicone resins and fluororesins, and non-aqueous polymer particles. . It is also possible to use a small amount of a crosslinking agent such as a melamine resin or a blocked isocyanate. Furthermore, if necessary, general paint additives such as an ultraviolet absorber, an antioxidant, a surface conditioner, and a defoaming agent can be blended.

The curable coating composition of the present invention is generally used as an organic solvent type coating composition. As the solvent,
Various organic solvents for coatings, for example, aromatic or aliphatic hydrocarbon solvents; alcohol solvents; ester solvents; ketone solvents; ether solvents can be used. As the organic solvent to be used, the one used at the time of preparing the polymer to be blended may be used as it is, or may be added as appropriate. The solid content concentration of the composition is not particularly limited, but is usually 20 to 8
It is about 0% by weight, preferably about 50 to 70% by weight.

The curable coating composition of the present invention is applied to various objects to be coated by a conventional method, and is usually sufficiently cured by heating at a temperature of about 100 to 180 ° C. for about 10 to 60 minutes. To form a coating film having excellent acid resistance, scratch resistance and stain resistance.

The method for forming a top coat according to the present invention is a method for forming a top coat in which a colored base coat and a clear top coat are sequentially formed on an object to be coated. And any one of the curable coating compositions (1) to (3) of the present invention.

[0114] Examples of the object to form the overcoat film include a steel plate which has been subjected to a chemical conversion treatment, a primer which is electrodeposited and, if necessary, an intermediate coating, and various plastic materials ( Surface treatment, primer coating, intermediate coating, etc., if necessary), and composite members in which these are combined.

In the method for forming a top coat according to the present invention,
The curable coating composition of the present invention is used as one or both of a coating forming a colored base coat and a coating forming a clear top coat.

Since the curable coating composition of the present invention can form a coating film having particularly excellent acid resistance, scratch resistance and stain resistance, it is preferable to use this as a coating material for forming a clear top coat.

The curable coating composition of the present invention can be used as it is as a clear top coat coating composition. Further, a coloring pigment can be added to the clear top coat coating composition to such an extent that the colored base coat is not completely concealed.

In the present invention, the above-mentioned curable coating composition is used as a coating composition for a colored base coat by appropriately blending the above-mentioned coloring pigment such as an organic pigment, an inorganic pigment or a metallic pigment. be able to.

The method for forming a coating film of the present invention is particularly suitable as a method for forming a top coating film for an automobile outer panel or the like. As the forming method, a coating system known in the automobile industry, for example, a method of forming a colored base coat / clear top coat by a two-coat one-bake method or a two-coat two-bake method;
A method of forming a colored base coat / clear top coat / clear top coat by a three-coat one-bake method or a three-coat two-bake method can be applied.

The most preferred method for forming a topcoat film of the present invention is to apply a paint for forming a colored base coat on an object to be coated and then apply a paint for forming a clear top coat on the coated surface without curing. Then, a two-coat one-bake system is used in which both coating films are cured by heating.

Next, a coating method by a two-coat one-bake method using the clear top coat coating composition containing the curable coating composition of the present invention as a resin component will be described.

In the two-coat one-bake method, a coating composition for a colored base coat is first applied on the object by a conventional method such as spray coating.

Examples of the coating composition for a colored base coat include:
The curable coating composition of the present invention may be used as a resin component, or a conventionally known coating composition for a colored base coat, which is conventionally used in a method for forming a top coat, may be used. good.

Examples of known coating compositions for a colored base coat include acrylic resin / amino resin (melamine resin and the like, the same applies hereinafter), alkyd resin / amino resin, polyester resin / amino resin, acrylic resin / A coating composition obtained by using a polyisocyanate-based resin, an alkyd resin / polyisocyanate-based resin, a polyester resin / polyisocyanate-based resin, or the like as a curable resin component and blending the above-mentioned coloring pigment with the curable resin component is exemplified. The form of these known colored base coat paint compositions is not particularly limited,
Any form such as an organic solvent type, a non-aqueous dispersion type, an aqueous solution type, an aqueous dispersion type, and a high solid type can be used.

Examples of the spraying machine used for spray coating include ordinary air spray guns, airless spray guns, air spray electrostatic coating machines, airless spray electrostatic coating machines, and rotary atomizing electrostatic coating machines. Etc. can be used.

The thickness of the coating composition for the colored base coat is preferably in the range of about 10 to 30 μm (after curing). After applying the coating composition for a colored base coat, leave it at room temperature for several minutes, or force-dry it for several minutes at a temperature in the range of about 50 to 80 ° C., and then use the curable coating composition of the present invention as a resin component. A clear top coat paint composition is applied.

The coating method and coating machine for the clear top coat coating composition are the same as those for the colored base coat coating composition.

The thickness of the clear top coat coating composition is preferably in the range of about 20 to 80 μm (after curing).

Next, both the colored base coat painted film and the clear top coat painted film are simultaneously cured by heating. The heating conditions in this case are about 100 to 18
At a temperature of 0 ° C. for about 10 to 60 minutes.

The article coated by the method of forming a coating film of the present invention has a coating film having excellent acid resistance, abrasion resistance and stain resistance, and is particularly suitable for automobile outer panels and the like.

[0131]

EXAMPLES Hereinafter, Production Examples, Examples and Comparative Examples will be given,
The present invention will be described more specifically. The parts and percentages in each example are based on weight.

Production Example 1 Production of Vinyl Polymer (a-1) Having Half Ester Group In a 5-liter glass flask equipped with a stirrer, a thermometer and a condenser, 553 parts of xylene and 3-methoxybutyl acetate were placed. Charge 276 parts and use electric heating mantle for 125
° C, and at that temperature, a mixture of the following monomer compositions was evenly dropped over 4 hours. Incidentally, p-tert-butylperoxy-2-ethylhexanoate is a polymerization initiator.

Methanol half-esterified maleic anhydride 288 parts (20%) n-butyl acrylate 864 parts (60%) Styrene 288 parts (20%) p-tert-butylperoxy-2-ethylhexanoate 72 parts Then, after aging for 30 minutes, 277 parts of 3-methoxybutyl acetate and p-tert-butylperoxy-
A mixture of 14.4 parts of 2-ethylhexanoate was added dropwise over 2 hours, and the mixture was aged for 2 hours.
An 8% solution of the acrylic polymer (a-1) was obtained.

The polymer solid content of the obtained polymer solution is 55
%, Gardner viscosity (25 ° C.) M. The number average molecular weight of this polymer was 3,500. The acid value of this polymer was 86 mgKOH / g.

Production Example 2 Production of vinyl polymer having carboxyl group (a-2) A final polymerization rate of 100 was obtained in the same manner as in Production Example 1 except that the monomer composition was changed as follows. %
A solution of the carboxyl group-containing acrylic resin (a-2) was obtained.

N-butyl methacrylate 432 parts (30%) isobutyl methacrylate 346 parts (24%) lauryl methacrylate 360 parts (25%) styrene 72 parts (5%) methacrylic acid 86 parts (6%) acrylic acid 144 parts (10 %) The polymer solid content of the obtained polymer liquid was 70%, the Gardner viscosity (25 ° C.) V, and the number average molecular weight of this polymer was 3,000. The acid value of this polymer is 11
It was 7 mgKOH / g.

Production Example 3 Half ester (a-3) formed by addition reaction between polyol and 1,2-acid anhydride
In a 5 liter glass flask equipped with a stirrer, thermometer and condenser, 236 parts of 3-methyl-1,5-pentanediol, 134 parts of trimethylolpropane, 1078 parts of hexahydrophthalic anhydride and 780 parts of xylene And heated to 120 ° C. in a nitrogen atmosphere to cause a reaction.
The reaction mixture was kept at this temperature for 4 hours and then cooled, solid content 65%, Gardner viscosity (25 ° C.) R, acid value 271 mg
A solution of KOH / g half ester (a-3) was obtained.

Production Example 3 Production of Vinyl Polymer Having Epoxy Group (b-1) 410 parts of xylene and n-butanol 7 were placed in a 5-liter glass flask equipped with a stirrer, thermometer and condenser.
After charging 7 parts, the mixture was heated to 125 ° C. with an electric heating mantle, and at that temperature, a mixture of the following monomer compositions was evenly dropped over 4 hours. Incidentally, azobisisobutyronitrile is a polymerization initiator.

Glycidyl methacrylate 432 parts (30%) n-butyl acrylate 720 parts (50%) Styrene 288 parts (20%) Azobisisobutyronitrile 72 parts Next, after aging for 30 minutes, 90 parts of xylene were further added.
A mixture of 40 parts of n-butanol and 14.4 parts of azobisisobutyronitrile was added dropwise over 2 hours.
After aging for a time, a solution of the acrylic polymer (b-1) having a final polymerization rate of 100% was obtained.

The polymer solid content of the obtained polymer solution was 70%.
% And Gardner viscosity (25 ° C.) S. The number average molecular weight of this polymer was 3,000. The epoxy group content of this polymer was 1.82 mmol / g.

Production Example 4 Production of Alicyclic Epoxy Group-Containing Acrylic Resin (b-2) In the same manner as in Production Example 3, except that only the monomer composition was changed as follows, the final polymerization rate was 100%. %
A solution of the alicyclic epoxy group-containing acrylic resin (b-2) was obtained.

432 parts (30%) of 3,4-epoxycyclohexylmethyl methacrylate 288 parts (20%) of styrene 720 parts (50%) of n-butyl acrylate The obtained polymer solution has a polymer solid content of 70% and a Gardner viscosity ( 25 ° C.) Q, and the number average molecular weight of this polymer was 3,000. The epoxy group content of this polymer was 1.32 mmol / g.

Production Example 5 Production of vinyl polymer (b-3) having epoxy group and hydrolyzable alkoxysilyl group Same as Production Example 3 except that the monomer composition was changed as follows in Production Example 3 And the final polymerization rate is 100%
A solution of the acrylic resin (b-3) containing an epoxy group and a hydrolyzable alkoxysilyl group was obtained.

Glycidyl methacrylate 504 parts (35%) γ-methacryloxypropyltriethoxysilane 216 parts (15%) n-butyl acrylate 432 parts (30%) Styrene 288 parts (20%) Polymer solid of the obtained polymer liquid The minute was 70% and the Gardner viscosity (25 ° C.) V. The number average molecular weight of this polymer was 3,000. The epoxy group content of the polymer was 2.12 mmol / g, and the ethoxysilyl group content was 1.55 mmol / g.

Production Example 6 Hydroxyl group-containing acrylic resin (c-
Production of 1) In Preparation Example 3, except that only the monomer composition was changed as described below, the final polymerization rate was 100% in the same manner as in Preparation Example 3.
Of a hydroxyl group-containing acrylic resin (c-1).

4-hydroxy n-butyl acrylate 432 parts (30%) n-butyl acrylate 576 parts (40%) styrene 432 parts (30%) The polymer solid content of the obtained polymer solution is 70%, and the Gardner viscosity ( (25 ° C.) U, and the number average molecular weight of this polymer was 3,000. The hydroxyl value of this polymer was 117 mgKOH / g.

Production Example 7 Production of vinyl polymer (c-2) having a hydroxyl group and a hydrolyzable alkoxysilyl group In the same manner as in Production Example 3, except that only the monomer composition was changed as follows, 100% final polymerization rate
Of a hydroxyl group- and hydrolyzable alkoxysilyl group-containing acrylic resin (c-2).

216 parts (15%) of 4-hydroxy n-butyl acrylate 216 parts (15%) of γ-methacryloxypropyltriethoxysilane 720 parts (50%) of n-butyl acrylate 288 parts (20%) of styrene The polymer liquid content of the obtained polymer solution was 70%, and Gardner viscosity (25 ° C.) V. The number average molecular weight of this polymer was 3,000. The hydroxyl value of this polymer was 58 mgKOH / g, and the ethoxysilyl group content was 1.55 mmol / g.

Production Example 8 Production of Vinyl Polymer (e-1) Having Epoxy and Hydroxyl Groups The final polymerization was carried out in the same manner as in Production Example 3 except that the monomer composition was changed as follows. Rate 100%
A solution of the acrylic polymer (e-1) was obtained.

Glycidyl methacrylate 432 parts (30%) 4-hydroxy n-butyl acrylate 288 parts (20%) n-butyl acrylate 432 parts (30%) Styrene 288 parts (20%) Polymer solid of the obtained polymer liquid The minute was 70% and the Gardner viscosity (25 ° C.) U. The number average molecular weight of this polymer was 3,000. The epoxy group content of this polymer was 2.12 mmol / g, and the hydroxyl value was 78 mg KO.
H / g. Production Example 9 Production of vinyl polymer (e-2) having an epoxy group, a hydroxyl group and a hydrolyzable alkoxysilyl group In Production Example 3, except that only the monomer composition was changed as described below, the same procedure as in Production Example 3 was carried out. 100% final polymerization rate
A solution of the acrylic polymer (e-2) was obtained.

Glycidyl methacrylate 504 parts (35%) 4-hydroxy n-butyl acrylate 216 parts (15%) γ-methacryloxypropyltriethoxysilane 216 parts (15%) n-butyl acrylate 216 parts (15%) Styrene 288 parts (20%) The obtained polymer liquid had a polymer solid content of 70% and a Gardner viscosity (25 ° C.) of V. The number average molecular weight of this polymer was 3,000. The epoxy group content of this polymer was 2.12 mmol / g, and the hydroxyl value was 78 mg KO.
H / g, ethoxysilyl group content is 1.55 mmol / g
Met.

Production Example 10 Production of Vinyl Polymer (f-1) Having Carboxyl Group and Hydroxyl Group The final polymerization was carried out in the same manner as in Production Example 1 except that only the monomer composition was changed as follows. Rate 100%
A solution of the acrylic polymer (f-1) was obtained.

Maleic anhydride methanol half esterified product 288 parts (20%) 4-hydroxy n-butyl acrylate 288 parts (20%) n-butyl acrylate 576 parts (40%) Styrene 288 parts (20%) The polymer liquid content of the obtained polymer solution was 55%, and the Gardner viscosity (25 ° C.) was M. The number average molecular weight of this polymer was 3,500. The acid value of this polymer is 8
The hydroxyl value was 6 mgKOH / g and the hydroxyl value was 78 mgKOH / g.

Production Example 11 Production of Organic Solvent-Type Colored Base Coating Paint Composition (Y-1) A mixture of the following components was mixed with 30 parts of toluene, 20 parts of isobutyl alcohol, 30 parts of cellosolve acetate and "Swazole 1000" (Cosmo Co., Ltd.). A mixed solvent consisting of 20 parts of a petroleum company (trade name, hydrocarbon solvent) having a viscosity of 1
The temperature was adjusted to 6 seconds (Ford cup # 4/20 ° C.) to obtain an organic solvent type coating composition (Y-1).

70% 70% acrylic resin (Note 1) 57 parts 70% half ester compound (Note 2) 43 parts 80% "Symel 202" (Note 3) 38 parts Aluminum paste (Note 4) 20 parts Xylene 30 parts (Note 1) ) 70% acrylic resin: An acrylic resin having a number average molecular weight of 5,000 and a resin solid content of 70%, obtained by polymerizing 45 parts of n-butyl methacrylate, 35 parts of glycidyl methacrylate and 20 parts of 2-hydroxyethyl acrylate in xylene. .

(Note 2) 70% half-ester compound: half-esterification reaction of 1 mol of trimethylolpropane with 2 mol of hexahydrophthalic anhydride in xylene, molecular weight 446, acid value 252 mgKOH / g, hydroxyl value 126 mgKOH / g, 70% solids compound.

(Note 3) 80% “Cymel 202”: a melamine resin with a resin solid content of 80%, manufactured by Mitsui Cytec Co., Ltd.

(Note 4) Aluminum paste: trade name “Alpaste 1830YL” manufactured by Toyo Aluminum Co., Ltd.
Aluminum flake paste, metallic pigment.

Examples 1 to 10 and Comparative Examples 1 to 3 After preparing a resin mixed solution with the composition (solid content) shown in Table 1, 2 parts of an equivalent composition of tetrabutylammonium bromide and monobutylphosphoric acid, "Tinuvin 900" (Product name, Ciba Geigy, UV absorber) 1 part and "BY
0.1 part of K-300 (trade name, manufactured by Big Chemie Co., surface conditioner), diluted with “Swazol 1000” (trade name, manufactured by Cosmo Oil Co., Ltd., hydrocarbon solvent), and viscosity was 25 seconds. (Ford cup # 4/20 ℃)
A coating composition of the present invention and a comparative coating composition were prepared. Further, the storage stability of each of the obtained compositions was tested by the following method.

Storage stability: The composition was treated with “Swazol 100
0 ”to a viscosity of 30 seconds (Ford Cup # 4/20 ° C.), 300 g of the diluted solution was placed in a beaker, lightly covered with aluminum foil, and then stored at 40 ° C. for 2 weeks (Ford Cup # 4). / 20 ° C) to determine the degree of thickening. The evaluation criteria are as follows.

A has good storage stability within 50 seconds of viscosity,
B shows that the storage stability is slightly inferior when the viscosity is 70 seconds or less, and C shows that the storage stability is inferior when the viscosity is 70 seconds or more.

The test results are shown in Table 1.

[0163]

[Table 1]

In Table 1, "ERL-4221" used as polyepoxide (B) and "TACT" used as compound (D) are as follows.

"ERL-4221": trade name, manufactured by Union Carbide Co., USA, 3,4-epoxycyclohexylmethyl-3,4-cyclohexanecarboxylate, a compound having two alicyclic epoxy groups, solid content 100%,
Epoxy group content 7.9 mmol / g.

"TACT": trade name, Scitech Co., Ltd.
Product, tris (methoxy / butoxycarbonylamino)
Triazine, 50% solids.

In Examples 1 to 7 and Comparative Example 1 in Table 1, the compounding ratio of the compound (A) to the polyepoxide (B) is determined by the equivalent of the carboxyl group of the compound (A) and the epoxy group of the polyepoxide (B). In terms of ratio, the former: the latter is 1: 1.2 in Examples 1 to 7, and 1: 1.2 in Comparative Example 1.
It is. The compounding ratio of the resin (C) is the same as that of the compound (A)
And total amount of solid content of polyepoxide (B) and resin (C)
In Examples 1 to 6, the weight ratio to the solid content was 84/16, Example 7 was 83/17, and Comparative Example 1 was 84/16. The compounding ratio of the compound (D) is as follows:
Total solid content of polyepoxide (B) and resin (C) 1
The solid content is 5 parts by weight in Examples 1 to 6, 11 parts by weight in Example 7, and 0 parts by weight in Comparative Example 1 with respect to 00 parts by weight.

In Example 8 and Comparative Example 2 in Table 1, the compounding ratio of the compound (A) to the resin (E) was as follows.
In terms of the equivalent ratio of the carboxyl group of the above to the epoxy group of the resin (E), the former: the latter is 1: 1.2 in Example 8 and 1: 1.2 in Comparative Example 2. The compounding ratio of the compound (D) is such that the total solid content of the compound (A) and the resin (E) is 1
The solid content is 5 parts by weight in Example 8 and 0 parts by weight in Comparative Example 2 with respect to 00 parts by weight.

In Example 10 and Comparative Example 3 in Table 1,
The mixing ratio of the resin (F) and the polyepoxide (B) is expressed by the equivalent ratio of the carboxyl group of the resin (F) to the epoxy group of the polyepoxide (B).
In Comparative Example 3, the ratio is 1: 1.2. The compounding ratio of the compound (D) was 5 parts by weight in Example 10 and 0 parts by weight in Comparative Example 3 with respect to 100 parts by weight of the total solids of the resin (F) and the polyepoxide (B). is there.

Examples 11 to 20 and Comparative Examples 4 to 6 Each of the coating compositions obtained in Examples 1 to 10 and Comparative Examples 1 to 3 was used as a clear top coat coating composition.
A top coat by two coats and one bake was formed as follows.

0.8 m thick with zinc phosphate chemical conversion treatment
m on a dull steel plate, electrodeposited an epoxy-based cationic electrodeposition paint so as to have a dry film thickness of about 20 μm.
After baking for a minute, sharpen with # 400 sandpaper,
After degreased by wiping with petroleum benzine, air spray coating was applied to an automotive intermediate coating surfacer to a dry film thickness of about 25 μm and baked at 140 ° C. for 30 minutes.
The sample was sanded with 400 sandpaper, drained and dried, and then degreased by wiping with petroleum benzene to obtain a test object.

Next, the metallic base coat paint (Y-1) obtained in Production Example 11 was spray-coated on the object to be cured so as to have a cured film thickness of 20 μm, and allowed to stand at room temperature for 5 minutes. The above-mentioned coating composition for clear top coating was spray-coated on the surface so as to have a cured film thickness of 40 μm, and heated at 140 ° C. for 30 minutes to cure both coating films, thereby forming a top-coating film.

The performance test of the obtained top coat was carried out as follows.

Coating appearance: The metallic feeling (glitter, whiteness, etc.) was visually evaluated. The evaluation criteria are as follows.

A indicates that the metallic feeling is excellent, B indicates that the metallic feeling is inferior, and C indicates that the metallic feeling is extremely inferior.

Acid resistance: 1% of test coated plate in 40% sulfuric acid solution
After immersion for 2 hours and left at 50 ° C. for 5 hours, it was washed with water and the coated surface was observed. The evaluation criteria are as follows.

A shows that there is no change, B shows that there is no abnormality in the coated surface, but shows a slight step at the boundary between the immersed part and the non-immersed part, and C shows that the coated surface is whitened.

Scratch resistance: After the automobile having the test coated plate attached to the roof was washed 15 times with a car washer, the coated surface of the coated plate was observed. The car washer was manufactured by Yasui Sangyo
0FWRC "was used. The evaluation criteria are as follows.

A shows that almost no damage is found by visual observation,
Shows slight scratches, but the degree is very slight, and C indicates that the scratches are conspicuous by visual observation.

Impact resistance: Using a Dupont impact tester, the test was performed with a radius of the tip of the bombardment point at 1/2 inch and a falling bell weight of 500 g. The evaluation was made based on the maximum height (in 5 cm increments) at which no cracks entered the coated surface.

Water resistance: After being immersed in warm water of 40 ° C. for 240 hours, it was washed with water and the coated surface was observed. The evaluation criteria are as follows.

A shows no change, B shows slightly glossy, and C shows whitening of the coated surface.

Recoat adhesion: 30 minutes at 140 ° C.
After baking for a minute, the same top coat (base coat /
Clear coat) was similarly coated, baked at 120 ° C. for 30 minutes, 100 cross cuts were inserted at 1 mm intervals, and the adhesion between the first and second coats when peeled off with a cellophane tape was examined. The evaluation criteria are as follows.

A shows no peeling, B shows slight peeling, and C shows remarkable peeling, respectively.

Organic contamination resistance: Pigeon droppings and water at 30:70
, And then stirred and filtered with gauze to prepare a test solution. 0.4cc of test solution on gradient oven
After spotting, heating at 65 ° C. for 30 minutes and cooling with water, the state of the coated surface was visually inspected. The evaluation criteria are as follows.

A shows no change, B shows a slight swelling, and C shows a clear swelling.

Urban-type pollution resistance: 0.25 g of 12 kinds of test dust (product of Japan Powder Industry Technology Association) and 9 parts of deionized water
9.75 g was mixed to prepare a test solution. The test liquid was sprayed on the coated surface by spraying, left at 25 ° C. and 75% RH for 17 hours, and then dried at 80 ° C. for 6 hours. This cycle is 4
After repeating this process, the coated surface was washed with sponge, and the carbon removal property of the coated surface was evaluated. The evaluation criteria are as follows.

A shows no change at all, B shows slight carbon adhesion, and C shows obvious carbon adhesion.

The test results are shown in Table 2.

[0190]

[Table 2]

[0191]

According to the present invention, a novel cure which can form a coating film having excellent acid resistance, abrasion resistance and stain resistance, and has excellent low-temperature curability, storage stability and recoat adhesion. A remarkable effect is provided in that a water-soluble paint composition and a method for forming a top coat using the composition are provided.

Continuation of front page (72) Inventor Masayuki Kagamiyama 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Kansai Paint Co., Ltd.

Claims (30)

[Claims] 1. A carboxyl group-containing compound (A), (B)
Polyepoxide, (C) a hydroxyl group-containing resin, and (D) a general formula [In the formula, R ¹ , R ² and R ³ are the same or different and each represent a hydrocarbon group having 1 to 20 carbon atoms. A curable coating composition comprising tris (alkoxycarbonylamino) triazine represented by the formula: 2. The compound (A) having an acid value of 50 to 500 mgK.
The composition according to claim 1, which is of OH / g. 3. The compound (A) has a number average molecular weight of 2,000.
The composition according to claim 1, which is an acrylic polymer of from 20,000 to 20,000. 4. The composition according to claim 1, wherein the compound (A) is a half ester formed by an addition reaction between a polyol and a 1,2-acid anhydride. 5. The composition according to claim 1, wherein the polyepoxide (B) has an epoxy group content of 0.8 to 15 mmol / g. 6. The composition according to claim 1, wherein the polyepoxide (B) is an acrylic polymer having a number average molecular weight of 2,000 to 20,000. 7. The composition according to claim 6, wherein the acrylic polymer contains a hydrolyzable alkoxysilyl group. 8. The resin (C) having a hydroxyl value of 5 to 200 mgK
The composition according to claim 1, which is of OH / g. 9. The resin (C) having a number average molecular weight of 2,000 to 2,000.
The composition according to claim 1, which is a 20,000 acrylic polymer. 10. The composition according to claim 9, wherein the acrylic polymer contains a hydrolyzable alkoxysilyl group. 11. The compounding ratio of the compound (A) to the polyepoxide (B) is from 1: 2 to 1: 1, based on the equivalent ratio of the carboxyl group of the compound (A) to the epoxy group of the polyepoxide (B).
0.7, and the mixing ratio of the resin (C) is 98/2 to 70/80 by weight ratio of the total solid content of the compound (A) and the polyepoxide (B) to the solid content of the resin (C). The compounding ratio of the compound (D) is 2 to 30% by weight based on 100 parts by weight of the total amount of the solids of the compound (A), the polyepoxide (B) and the resin (C). The composition of claim 1 which is a part. (A) a carboxyl group-containing compound,
(E) a resin containing an epoxy group and a hydroxyl group, and (D) a general formula: [In the formula, R ¹ , R ² and R ³ are the same or different and each represent a hydrocarbon group having 1 to 20 carbon atoms. A curable coating composition comprising tris (alkoxycarbonylamino) triazine represented by the formula: 13. The compound (A) having an acid value of 50 to 500 mg.
13. The composition according to claim 12, which is of KOH / g. 14. Compound (A) having a number average molecular weight of 2,000
13. An acrylic polymer of 0 to 20,000.
A composition as described. 15. A compound (A) comprising a polyol and 1,2-
The composition according to claim 12, which is a half ester formed by an addition reaction with an acid anhydride. 16. The resin (E) having an epoxy group content of 0.5
-5 mmol / g, hydroxyl value 5-200 mgKOH / g
The composition according to claim 12, which is 17. The resin (E) having a number average molecular weight of 2,000
13. The composition according to claim 12, which is an acrylic polymer of up to 20,000. 18. The composition according to claim 17, wherein the acrylic polymer contains a hydrolyzable alkoxysilyl group. 19. The compounding ratio of the compound (A) to the resin (E) is 1: 2 to 1: 0.7 in equivalent ratio of the carboxyl group of the compound (A) to the epoxy group of the resin (E). The compounding ratio of the compound (D) is 2 in solid content with respect to 100 parts by weight of the total solid content of the compound (A) and the resin (E).
The composition according to claim 12, wherein the amount is from 30 to 30 parts by weight. 20. (F) a resin containing a carboxyl group and a hydroxyl group, (B) a polyepoxide, and (D) a general formula: [In the formula, R ¹ , R ² and R ³ are the same or different and each represent a hydrocarbon group having 1 to 20 carbon atoms. A curable coating composition comprising tris (alkoxycarbonylamino) triazine represented by the formula: 21. The polyepoxide (B) having an epoxy group content of 0.8 to 15 mmol / g.
A composition as described. 22. The composition according to claim 20, wherein the polyepoxide (B) is an acrylic polymer having a number average molecular weight of 2,000 to 20,000. 23. The composition according to claim 22, wherein the acrylic polymer contains a hydrolyzable alkoxysilyl group. 24. The resin (F) having an acid value of 30 to 240 mgK.
21. The composition according to claim 20, which has an OH / g and a hydroxyl value of 5 to 200 mgKOH / g. 25. The resin (F) having a number average molecular weight of 2,000
21. The composition according to claim 20, which is an acrylic polymer of up to 20,000. 26. The compounding ratio of the resin (F) to the polyepoxide (B) is 1: 2 to 1: 0.7 in the equivalent ratio of the carboxyl group of the resin (F) to the epoxy group of the polyepoxide (B).
Where the compounding ratio of the compound (D) is 100 and the total solid content of the resin (F) and the polyepoxide (B) is 100.
3. A solid content of 2 to 30 parts by weight based on parts by weight.
0. The composition of claim 0. 27. A method for forming a top coat by sequentially forming a colored base coat and a clear top coat on an object to be coated, wherein the paint for forming the colored base coat and / or the clear top coat is the above-mentioned coating composition. 2
A method for forming a topcoat film, which is the coating composition according to item 0. 28. A method for forming a topcoat film, comprising applying a coating material for forming a colored base coat on an object to be coated, applying a coating material for forming a clear top coat on the coated surface without curing, and then applying both coating materials. 28. The method for forming a topcoat film according to claim 27, wherein the method is a two-coat one-bake method in which the film is cured by heating. 29. The method for forming a top coat according to claim 27, wherein the paint for forming the clear top coat is the paint composition according to claim 1, 12 or 20. 30. An article coated by the method according to claim 27.