JP2001279164A - Paint composition - Google Patents

Abstract

(57) [Abstract] [Problem] Acid resistance, car wash abrasion resistance, chipping resistance,
Provided is a coating composition which is excellent in coating film performance such as interlayer adhesion and can form a coating film having excellent finished appearance such as sharpness, transparency and coloring. SOLUTION: (A) (a) 0.1 of a polymerizable unsaturated monomer containing at least one hydrophilic functional group selected from an amino group, a quaternary ammonium base and a sulfonic acid group;
(B) 6 to 50% by weight of a hydroxyl group-containing polymerizable unsaturated monomer, (c) 0.1 to 10% by weight of a phosphate group-containing polymerizable unsaturated monomer, and (d) other polymerizable unsaturated A coating composition comprising a copolymer resin of a monomer mixture consisting of 30 to 90% by weight of a monomer and [B] a curing agent, and a method of finishing a top coat on an object to be coated. A top coat finish method, wherein the paint composition according to 1 is applied as a top coat colored enamel paint or a top coat clear paint.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition, particularly a coating composition suitable as a top coating for automobiles, and a method for finishing a top coat using the coating composition.

[0002]

2. Description of the Related Art Hitherto, as a resin component for a coating having excellent durability such as a top coating for automotive coating,
A curing agent such as an amino resin, an optionally blocked polyisocyanate compound, or an epoxy compound is added to a base resin (base polymer) component such as an acrylic resin, a polyester resin, or an alkyd resin having a functional group such as a hydroxyl group or a carboxyl group. Those used in combination are widely used.

[0003] At present, the required performance level of top coatings for automotive coatings and the like tends to be more and more severe. For example, the finished appearance of the coating film, such as sharpness, transparency, and coloring, is required as well as the coating film performance such as high durability, acid resistance, car wash abrasion resistance, and chipping resistance. However, a coating composition satisfying all of these required properties has not been found. Among them, the performance such as pigment dispersibility and letdown stability (color stability) necessary for forming a coating film having particularly excellent finished appearance is based on acrylic resin, polyester resin, Not only is it difficult to achieve even when a pigment dispersant such as a urethane resin or a polyester-modified urethane resin is used in combination, but if these pigment dispersants are incorporated in a large amount in the paint, a coating film such as weather resistance and physical performance can be obtained. There is a problem that the performance is reduced.

The main object of the present invention is to provide excellent coating properties such as acid resistance, car wash abrasion resistance, chipping resistance, and adhesion between layers, as well as excellent appearance such as sharpness, transparency, and coloring. An object of the present invention is to provide a coating composition capable of forming a coating film, and to provide a method for finishing a top coating capable of forming a top coating film having excellent coating film performance and finished appearance.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, in particular, selected from specific hydrophilic functional groups (amino groups, quaternary ammonium bases and sulfonic acid groups). The above object is achieved by using a copolymer resin obtained by copolymerizing a monomer mixture having a polymerizable unsaturated monomer having a functional group), a polymerizable unsaturated monomer having a hydroxyl group and a polymerizable unsaturated monomer having a phosphate group. Have been achieved, and the present invention has been completed.

That is, the present invention relates to (A) (a) a polymerizable unsaturated monomer containing at least one hydrophilic functional group selected from an amino group, a quaternary ammonium base and a sulfonic acid group. (B) 6 to 50% by weight of a hydroxyl group-containing polymerizable unsaturated monomer, (c) 0.1 to 10% by weight of a phosphate group-containing polymerizable unsaturated monomer, and (d) other polymerizable unsaturated monomer 30 A resin having a hydroxyl value of from 30 to 200 mgKOH / g, obtained by copolymerizing a monomer mixture consisting of .about.90% by weight, and [B]
It is intended to provide a coating composition comprising a curing agent.

Further, in the present invention, at least a part of the other polymerizable unsaturated monomer (d) is represented by the following formula (I):

[0008]

Embedded image

Wherein R ¹ and R ² are the same or different and each represent an alkyl group having 1 to 6 carbon atoms, and R ³ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The present invention provides the above coating composition, which is a (meth) acrylate monomer having a branched alkyl group having 8 to 24 carbon atoms having a moiety.

[0010] The present invention further provides the above-mentioned coating composition, which further comprises a coating resin [C] other than the above-mentioned copolymer resin [A]. Is provided.

Further, the present invention provides the above-mentioned coating composition, further comprising a pigment.

Further, the present invention provides a method for finishing a top coat on an object to be coated, wherein the coating composition of the present invention is applied as a top coat colored enamel paint or a top coat clear paint. Is what you do.

[0013] The present invention also provides a method for finishing a top coat on an object to be coated, wherein the coating composition of the present invention containing a pigment is applied as a top coat colored enamel paint. Things. Hereinafter, the present invention will be described in detail.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The coating composition of the present invention contains the following copolymer resin [A], curing agent [B] and, if necessary, binder resin [C] for coating.

[0015] Copolymer resin [A] : The copolymer resin as the component [A] in the composition of the present invention is a polymerizable unsaturated monomer (a) containing a specific hydrophilic functional group, a hydroxyl group-containing polymerizable polymer. It is a resin obtained by copolymerizing a monomer mixture comprising an unsaturated monomer (b), a polymerizable unsaturated monomer having a phosphoric acid group (c), and another polymerizable unsaturated monomer (d).

The polymerizable unsaturated monomer (a) containing the specific hydrophilic functional group (hereinafter sometimes abbreviated as “monomer (a)”) has one polymerizable unsaturated group in one molecule. And a monomer having at least one specific hydrophilic functional group, wherein the specific hydrophilic functional group is a group selected from an amino group, a quaternary ammonium base, and a sulfonic acid group.

Specific examples of the monomer (a) include, for example, N, N-dimethylaminoethyl (meth) acrylate,
N, N-diethylaminoethyl (meth) acrylate,
Aminoalkyl (meth) containing a tertiary amino group such as N, N-dimethylaminopropyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, and N, N-dimethylaminobutyl (meth) acrylate Acrylates; quaternary ammonium base-containing monomers such as methacryloyloxyethyltrimethylammonium chloride; and sulfonic acid group-containing polymerizable unsaturated monomers such as 2-acrylamido-2-methylpropanesulfonic acid. These compounds may be used alone or
It can be used in combination of more than one species.

In the present specification, “(meth) acrylate” means “acrylate or methacrylate”.

When the monomer (a) is a polymerizable unsaturated monomer containing a tertiary amino group and / or a quaternary ammonium salt group, these groups may be used to disperse the pigment in acidic pigments and neutral pigments. When the monomer (a) is a sulfonic acid group-containing polymerizable unsaturated monomer, the sulfonic acid group effectively affects the pigment dispersibility of the basic pigment.

The hydroxyl group-containing polymerizable unsaturated monomer (b) is a polymerizable unsaturated monomer containing one or more hydroxyl groups in one molecule, and may be abbreviated as “monomer (b)” hereinafter. . Specific examples of the monomer (b) include, for example, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2,3
Monoesters of polyhydric alcohols with acrylic acid or methacrylic acid, such as dihydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and polyethylene glycol mono (meth) acrylate; Compounds obtained by ring-opening polymerization of ε-caprolactone to a monoesterified product with methacrylic acid can be exemplified. Among them, compounds obtained by ring-opening polymerization of ε-caprolactone with 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and a monoesterified product of polyhydric alcohol and acrylic acid or methacrylic acid are reactive. It is preferable from the point. The above compounds exemplified as the monomer (b) can be used alone or in combination of two or more.

The above-mentioned phosphoric acid group-containing polymerizable unsaturated monomer (c) is a polymerizable unsaturated monomer containing one or more phosphoric acid groups in one molecule, and is hereinafter abbreviated as "monomer (c)". Sometimes. Specific examples of the monomer (c) include 2-methacryloyloxyethyl acid phosphate, 2-allylyloxyethyl acid phosphate, and monoalkyl (butyl, decyl, lauryl, stearyl, etc.) phosphoric acid to which glycidyl methacrylate is added. The polymerizable unsaturated monomer obtained by adding glycidyl methacrylate to benzyl phosphoric acid, and the like, can be used. These can be used alone or in combination of two or more.

The other polymerizable unsaturated monomer (d)
Is a polymerizable unsaturated monomer other than the above-mentioned monomer (a), monomer (b) and monomer (c), and is a monomer that is appropriately used depending on properties of a required resin. d) ".

Specific examples of the monomer (d) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, C such as isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate
_1-9 alkyl (meth) acrylate; benzene ring-containing polymerizable unsaturated monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, phenyl (meth) acrylate; acrylonitrile, meta Acrylonitrile and the like can be mentioned. These compounds can be used alone or in combination of two or more.

The monomer (d) has 8 carbon atoms.
It is preferable to contain a (meth) acrylic acid ester monomer having from 24 to 24 branched alkyl groups (hereinafter, sometimes abbreviated as “long-chain branched monomer”). The long-chain branched monomer is a branched alkyl group having 8 to 24 carbon atoms.
The following formula (I)

[0025]

Embedded image

Wherein R ¹ and R ² are the same or different and represent an alkyl group having 1 to 6 carbon atoms, and R ³ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. With parts. Specific examples of the long-chain branched monomer include, for example, the following formula (II)

[0027]

Embedded image

A compound represented by the formula: wherein R ⁴ represents a hydrogen atom or a methyl group; Cardura (Cardura)
E10 (manufactured by Shell Chemical Company, registered trademark, carbon number 9)
To 11 branched higher fatty acids) and an equimolar ester of acrylic acid or methacrylic acid. These compounds may be used alone or
More than one species can be used in combination. The long-chain branched monomer forms a steric repulsion layer to prevent aggregation between pigments,
In particular, it is advantageous for letdown stability and is also advantageous from the viewpoint of high pigment concentration (high solid differentiation).

The amount of the monomers (a), (b), (c) and (d) used in the production of the copolymer resin [A] in the present invention constitutes the copolymer resin [A]. Suitably, it is within the following range based on the total amount of all monomer components. Monomer (a): 0.1 to 10% by weight, preferably 0.1 to 10% by weight.
2 to 8% by weight, monomer (b): 6 to 50% by weight, preferably 10 to 4%
0% by weight, monomer (c): 0.1 to 10% by weight, preferably 0.1 to 10% by weight.
5 to 8% by weight, monomer (d): 35 to 90% by weight, preferably 45 to 90% by weight
80% by weight.

The amount of the monomer (b) is usually 30 to 200 mgKOH / g, preferably 40 to 200 mgKOH / g.
It is in the range of ~ 150 mgKOH / g. The amount of the monomer (c) is usually 0.5 to 40 mgK in acid value.
OH / g, preferably 1 to 20 mgKOH / g. It is preferable to use the long-chain branched monomer as a part of the monomer (d), and the blending amount of the long-chain branched monomer is based on the total amount of all the monomer components constituting the copolymer resin [A]. Preferably it is in the range of 5 to 40% by weight.

When the monomer composition of the copolymer resin as the component (A) in the present invention is within the above range, the physical properties such as the finished appearance and durability of the coating film, the car wash abrasion resistance, and the chipping resistance are provided. It is suitable from the viewpoints of properties, interlayer adhesion, pigment dispersibility, letdown stability (color stability), and the like. Here, the amount of the monomer (a) is preferably within the above range from the viewpoint of pigment dispersibility, letdown stability (color stability) and the like. The type of the monomer (a) can be appropriately selected according to the type of the pigment, the specific surface area and the particle size of the pigment particles, the presence or absence or properties of the pigment surface treating agent, the polarity of the dispersion medium, and the like. The monomer (b) contains a hydroxyl group which is a cross-linking reactive group, and is preferably in the above range from the viewpoint of the curability, durability, chipping resistance, car wash abrasion resistance and physical performance of the coating film. The monomer (c) is a monomer containing a phosphate group, and preferably has the above range from the viewpoint of chipping resistance, interlayer adhesion and the like. By containing a phosphate group, especially for a coating composition containing a metallic pigment such as aluminum,
It also has the function of preventing cohesive failure of the metallic pigment and improving the orientation.

The method of copolymerizing the monomer mixture comprising the monomers (a), (b), (c) and (d) to obtain the copolymer resin [A] is a polymerization method known per se. Examples include a bulk polymerization method, a solution polymerization method, a bulk-suspension two-stage polymerization method in which suspension polymerization is performed after the bulk polymerization, and the like.

When the copolymer resin [A] is obtained by copolymerization, a polymerization initiator generally used in a production method of an acrylic polymer or the like is used as a polymerization initiator, and the amount thereof is usually It is in the range from 0.1 to 8% by weight, based on the total amount of monomers (a), (b), (c) and (d), and optionally also monomer (e).

As the above-mentioned polymerization initiator, for example, 2,2 '
Azo polymerization initiators such as azobisisobutylnitrile, azobis-2-methylbutyronitrile, azobisdivaleronitrile, etc .; t-butylperoxyisobutyrate, t
-Butylperoxy-2-ethylhexanoate, t-
Amyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxyisopropyl carbonate,
2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane, di-tert-butyl peroxide,
Organic peroxide-based polymerization initiators such as di-t-amyl peroxide can be used.

As a method for obtaining the copolymer resin [A],
Among them, the solution polymerization method is preferred. Examples of the solution polymerization method include a method in which the monomer mixture is dissolved or dispersed in an organic solvent, and the mixture is heated with stirring at a temperature of usually about 80 ° C to 200 ° C in the presence of a radical polymerization initiator. it can. The appropriate reaction time is usually about 1 to 10 hours.

Examples of the organic solvent include hydrocarbon solvents such as heptane, toluene, xylene, octane, and mineral spirit; esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether acetate. Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol and isobutanol; n-butyl ether, dioxane, ethylene glycol monomethyl Ether solvents such as ether and ethylene glycol monoethyl ether; Swazole 310, Swazole 1000, Swazo manufactured by Cosmo Oil Co., Ltd. And aromatic petroleum solvents such as C.I. These organic solvents can be used alone or in combination of two or more. At the time of copolymerization, the organic solvent is a monomer (a),
The total amount of (b), (c) and (d) is usually 4
It is used in a range of not more than 00% by weight.

In the copolymerization reaction for obtaining the copolymer resin [A], the method of adding the monomer component and the polymerization initiator is not particularly limited. From the point of view, it is preferable to divide and drop several times over the latter stage of the polymerization from the viewpoint of suppressing the formation of defective crosslinked products.

The copolymer resin [A] obtainable by the above copolymerization has a weight average molecular weight of 5,000 to 10
It is preferably in the range of 0000, preferably 10,000 to 70,000, so that the finished appearance of the coating film, physical properties such as durability, chipping resistance, interlayer adhesion, pigment dispersibility, let-down stability. It is suitable from the viewpoints of properties (color stability), ease of handling of the resin (resin viscosity not extremely high), and the like.

Curing agent [B]: The curing agent which is the component [B] in the composition of the present invention includes a copolymer resin [A]
Any resin can be used without particular limitation as long as it can react with a hydroxyl group therein or a functional group in a coating binder resin [C] to be contained as required to form a cured coating film. As the curing agent [B], for example, amino resin,
Suitable examples include a polyisocyanate compound which may be blocked, and when the coating binder resin [C] is a carboxyl group-containing resin, in addition to the above, a polyvalent epoxy resin may be used. Suitable compounds include a group-containing compound and an epoxy group-containing acrylic resin.

Examples of the amino resin include a methylolated amino resin obtained by reacting an amino component such as melamine, urea, benzoguanamine, acetoguanamine, spiroguanamine, and dicyandiamide with an aldehyde. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde. Further, those obtained by etherifying the methylolated amino resin with one or more alcohols may be used. Examples of the alcohol used for the etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n -Butyl alcohol, isobutyl alcohol, 2
Monohydric alcohols such as -ethylbutanol and 2-ethylhexanol. Among these, a methylolated melamine resin or a melamine resin obtained by etherifying at least a part of the methylol group of the methylolated melamine resin with a monohydric alcohol having 1 to 4 carbon atoms is preferable.

Commercially available melamine resins include, for example, Uban 20SE-60 and Uban 225 (all of which are trade names of Mitsui Chemicals, Inc., Super Beckamine G).
Butyl etherified melamine resins such as 840 and G821 (all of which are manufactured by Dainippon Ink and Chemicals, Inc.); Sumimar M-100, M-40S, and M-55
(These are all manufactured by Sumitomo Chemical Co., Ltd., trade name), Cymel 3
03, 325, 327, 350, and 370 (all, manufactured by Mitsui Cytec Co., Ltd., trade name), Nikarac MS17, MS15 (all, manufactured by Sanwa Chemical Co., trade name), Regin 741 ( Methyl etherified melamine resin such as Monsanto (trade name); Cymel 2
35, 202, 238, 254, 272, 1
A mixed etherified melamine resin of methylation and isobutylation such as 130 (all of which are manufactured by Mitsui Cytec Co., Ltd., trade name) and Sumamil M66B (trade name of Sumitomo Chemical Co., Ltd.); Cymel XV805 (manufactured by Mitsui Cytec Co., Ltd., trade name) Melamine resin mixed with methylation and n-butylation such as Nicarac MS95 (trade name, manufactured by Sanwa Chemical Co., Ltd.).

The optionally blocked polyisocyanate compound which can be used as a curing agent may be any of a polyisocyanate compound having a free isocyanate group and a polyisocyanate compound having a blocked isocyanate group.

Examples of the polyisocyanate compound having a free isocyanate group include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cycloaliphatic diisocyanates such as hydrogenated xylylene diisocyanate and isophorone diisocyanate; tolylene diisocyanate Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate; triphenylmethane-4,4 ', 4 "-triisocyanate, 1,3,5
3 such as -triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate;
An organic polyisocyanate itself such as a polyisocyanate compound having at least two isocyanate groups, or each of these organic polyisocyanates and a polyhydric alcohol;
Examples thereof include an adduct with a low molecular weight polyester resin or water, a cyclized polymer of the above-mentioned organic polyisocyanates, and an isocyanate / biuret compound.

Commercially available polyisocyanate compounds having a free isocyanate group include, for example, Vernock D-750, -800, DN-950, and DN-950.
970, DN-15-455 (both from Dainippon Ink and Chemicals, Inc.), Desmodur L, N, and H
L, N3390 (all of which are manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name), Takenate D-102, and -20
2, -110, -123N (all, manufactured by Takeda Pharmaceutical Company, trade name), Coronate EH, L, H
L. and 203 (all, manufactured by Nippon Polyurethane Industry Co., Ltd., trade name), Duranate 24A-90CX (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.) and the like.

As the polyisocyanate compound in which the isocyanate group is blocked, the isocyanate group of the above-mentioned polyisocyanate compound having a free isocyanate group may be replaced with a known block such as oxime, phenol, alcohol, lactam, malonic ester or mercaptan. And those blocked with an agent. Examples of these typical commercial products include Burnock D-550 (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) and Takenate B-8.
15-N (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.), Aditol VXL-80 (trade name, manufactured by Hoechst, Germany), Coronate 2507 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.), Desmodur N3500 (Sumitomo Bayer Urethane) Company name, product name).

When the coating binder resin [C] is a carboxyl group-containing resin, a polyvalent epoxy group-containing compound, an epoxy group-containing acrylic resin, or the like can be suitably used as the curing agent [B]. The polyvalent epoxy group-containing compound is a compound having two or more epoxy groups in a molecule, and usually has an epoxy equivalent of 200 to 1500 g / equivalent,
Preferably, the compound is in the range of 280 to 800 g / equivalent.

Representative examples of the polyvalent epoxy group-containing compound include ethylene glycol diglycidyl ether,
Polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl Ether, glycerin diglycidyl ether, diglycerin tetraglycidyl ether, trimethylolpropane triglycidyl ether, 2,6-diglycidylphenyl ether, sorbitol triglycidyl ether, triglycidyl isocyanurate, diglycidylamine, diglycidylbenzylamine, phthalic acid Diglycidyl ester, bisphenol A diglycidyl ether, butadiene dioxy Id, dicyclopentadienedioxide, diester of 3,4-epoxycyclohexene carboxylic acid and ethylene glycol, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexyl Methyl-3,4-epoxy-6-methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, dicyclopentadiene epoxide glycidyl ether, dipentenedionoxide, addition of bisphenol A type epoxy resin to ethylene oxide Thing, Eporide GT30
0 (manufactured by Daicel Chemical Industries, Ltd.), trifunctional alicyclic epoxy compound), Eporide GT400 (manufactured by Daicel Chemical Industries, Ltd., tetrafunctional alicyclic epoxy compound); Eporide GT301, GT302, GT303 (above, All are manufactured by Daicel Chemical Industries, Ltd., ring-opened ε-caprolactone chain-containing trifunctional alicyclic epoxy compound);
Epicoat 82: T401, GT402, and GT403 (all of which are manufactured by Daicel Chemical Industries, Ltd., and a ring-opened ε-caprolactone chain-containing tetrafunctional alicyclic epoxy compound);
8, 834, 1001 (all of which are manufactured by Yuka Shell Epoxy Co., Ltd., bisphenol A type epoxy resin); Epicoat 154 (Yuka Shell Epoxy Co., Ltd.)
Cresol novolak type epoxy resin), celloxides 2081 and 208 represented by the following formula (III):
2, 2083 (both are manufactured by Daicel Chemical Industries, Ltd .; in formula (III) below, k = 1 is celloxide 2081 and k = 2 is celloxide 20)
82, k = 3 is a celloxide 2083); and Denacol EX-411 (manufactured by Nagase Kasei Co., Ltd.) represented by the following formula (IV).

[0048]

Embedded image

(In the formula (III), k represents an integer of 1 to 3.)

Examples of the epoxy group-containing acrylic resin that can be used as the curing agent [B] include a copolymer of a vinyl monomer having an epoxy group and another vinyl monomer.

Examples of the vinyl monomer having an epoxy group include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, allyl glycidyl ether, and vinyl glycidyl ether. Can be. Examples of other vinyl monomers include monomers that can be used as a monomer constituting the copolymer resin [A], other than the vinyl monomer having an epoxy group. The epoxy group-containing acrylic resin preferably has a number average molecular weight in the range of 1,000 to 20,000 and an epoxy equivalent in the range of 200 to 800.

The above curing agents can be used alone or in combination of two or more. As a combination of two or more, for example, when the paint binder resin [C] has a hydroxyl group as a functional group, a combination of an amino resin and a polyisocyanate compound, and the paint binder resin [C] has a carboxyl group as a functional group When the compound has a group, a combination of an amino resin and a polyvalent epoxy group-containing compound, a combination of a polyisocyanate compound and a polyvalent epoxy group-containing compound, and the like can be given.

Binder resin for paint [C]: The binder resin for paint [C] is to be added to the paint composition of the present invention as needed, and typical examples thereof include the following hydroxyl group-containing acrylic resin. Hydroxyl-containing resins such as resin (C-1) and hydroxyl-containing polyester resin (C-2); carboxyl-containing resins such as carboxyl-containing acrylic resin (C-3) and carboxyl-containing polyester resin (C-4) Can be mentioned.

The above-mentioned hydroxyl group-containing acrylic resin (C-1)
Is a copolymer of a vinyl monomer having a hydroxyl group and another vinyl monomer.

As the vinyl monomer having a hydroxyl group,
The monomer (b) in the copolymer resin [A] can be mentioned. Hydroxyl group-containing acrylic resin (C-1)
Preferably has a number average molecular weight in the range of 1,000 to 50,000 and a hydroxyl value in the range of 10 to 200 mgKOH / g.

Hydroxyl-containing polyester resin (C-2)
Is ethylene glycol, butylene glycol, 1,6
-Polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol and adipic acid,
It can be easily obtained by a condensation reaction with a polycarboxylic acid such as terephthalic acid, isophthalic acid, phthalic anhydride and hexahydrophthalic anhydride. The hydroxyl group-containing polyester resin has a number average molecular weight of usually 500 or more,
It is preferable to be about 1,000 to 30,000, and the hydroxyl value is preferably in the range of 10 to 200 mgKOH / g.

The carboxyl group-containing acrylic resin (C)
Examples of -3) include a copolymer of a vinyl monomer having a carboxyl group and another vinyl monomer.

Examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, and maleic acid; and acid anhydrides of vinyl monomers having an acid anhydride group such as maleic anhydride and itaconic anhydride. A vinyl monomer having a group obtained by half-esterifying a group can be used. 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.

As the carboxyl group-containing acrylic resin, a copolymer of a vinyl monomer having an acid anhydride group such as maleic anhydride and itaconic anhydride with another vinyl monomer is produced, and then the acid anhydride of the copolymer is produced. Those obtained by half-esterifying a group can also be mentioned. That is, when a half ester group is introduced into the copolymer, the half esterification may be performed before or after the copolymerization reaction.

As the aliphatic monoalcohol used for the half esterification, low molecular weight monoalcohols such as methanol, ethanol, propanol and tert-
Butanol, isobutanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and the like. The half-esterification reaction can be carried out according to a usual method, at a temperature from room temperature to 80 ° C., using a tertiary amine as a catalyst if necessary.

The carboxyl group-containing acrylic resin (C)
Other vinyl monomers for obtaining -3) include:
For example, the monomer (d) constituting the copolymer resin [A] can be mentioned.

Carboxyl group-containing acrylic resin (C-
The amount of the vinyl monomer having a carboxyl group, a half ester group or an acid anhydride group for obtaining 3) is 5 to 40% by weight, preferably 10 to 30% by weight of the total amount of the monomers to be copolymerized.
Suitably, it is in the range of weight percent. When a vinyl monomer having an acid anhydride group is used, half esterification after polymerization is as described above.

The carboxyl group-containing acrylic resin (C-
In 3), the number average molecular weight is preferably in the range of 2,000 to 10,000, and the acid value is preferably in the range of 50 to 500 mgKOH / g.

As the carboxyl group-containing polyester resin (C-4), for example, a carboxyl group-containing polyester polymer or a number-average molecular weight of less than 1,000 produced by an addition reaction between a polyol and a 1,2-acid anhydride. Low molecular weight half esters (hereinafter sometimes referred to as “low molecular weight half esters”) and the like can be mentioned. Among them, low molecular weight half esters can be mentioned as preferred.

The carboxyl group-containing polyester polymer includes ethylene glycol, butylene glycol,
1,6-hexanediol, trimethylolpropane,
It can be easily obtained by a condensation reaction of a polyhydric alcohol such as pentaerythritol and a polycarboxylic acid such as adipic acid, terephthalic acid, isophthalic acid, phthalic anhydride and hexahydrophthalic anhydride. The carboxyl group-containing polyester resin has a number average molecular weight of usually 1,000
It is suitably 0 or more, preferably in the range of about 1,100 to 2,000, and the resin acid value is suitably in the range of 50 to 500 mgKOH / g, preferably 40 to 200 mgKOH / g.

The low-molecular-weight half ester is obtained by reacting a polyol with a 1,2-acid anhydride under a condition in which a ring-opening reaction of the acid anhydride occurs and a polyesterification reaction by a generated carboxyl group does not substantially occur. It is obtained by doing. The low molecular weight half ester has a number average molecular weight of 1,
000, preferably in the range of 400-900, with an acid value of 50-500 mg KOH / g, preferably 4
Suitably, it is in the range of 0-200 mg KOH / g.

The polyol used for preparing the low molecular weight half ester is a polyol having about 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, for example, ethylene glycol, 1,2- or 1,3-propanediol. , Butylene glycol, neopentyl glycol, 1,6-hexanediol, glycerin, 1,1,1-trimethylolpropane, 1,2,3-butanetriol, diethylene glycol, dipropylene glycol, 1,4-dimethylolcyclohexane, Examples thereof include pentaerythritol, bisphenol A, bisphenol F, and bis (hydroxymethyl) xylene.

The 1,2-acid anhydride used in the preparation of the low-molecular-weight half ester is preferably one having about 4 to 32 carbon atoms, such as succinic anhydride, methylsuccinic anhydride and dodecenylsuccinic acid. Anhydride, octadecenylsuccinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, alkylhexahydrophthalic anhydride (for example, methylhexahydro (Phthalic anhydride), tetrafluorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, chlorendic anhydride, itaconic anhydride, citraconic anhydride, maleic anhydride and the like.

The low-molecular-weight half ester is obtained by reacting the polyol and 1,2-acid anhydride, for example, under a nitrogen atmosphere.
It can be obtained by reacting in a solvent at 70 to 150 ° C, preferably 90 to 120 ° C, usually for 10 minutes to 24 hours. The mixing ratio of the polyol and the 1,2-acid anhydride is calculated assuming that the acid anhydride group is monofunctional, and the equivalent ratio of hydroxyl group: acid anhydride group is in the range of about 0.8: 1 to 1.2: 1. It is suitable.

When a carboxyl group-containing resin such as a carboxyl group-containing acrylic resin and a carboxyl group-containing polyester resin is used as the coating binder resin [C],
As the curing agent [B], a polyvalent epoxy group-containing compound and an epoxy group-containing acrylic resin can be used.

The coating composition of the present invention contains the above-mentioned copolymer resin [A] and curing agent [B] as essential components, and may contain a binder resin [C] for coating, if necessary. These compounding ratios are preferably in the following range in terms of the solid content based on 100 parts by weight of the total solid content of the components [A], [B] and [C]. Copolymer resin [A]: 10 to 90 parts by weight, preferably 2
0 to 70 parts by weight, curing agent [B]: 10 to 50 parts by weight, preferably 20 to 4 parts
0 parts by weight, binder resin for coating [C]: 0 to 80 parts by weight, preferably 0 to 50 parts by weight.

The coating composition of the present invention contains the above-mentioned copolymer resin [A] and curing agent [B] as essential components, and if necessary, contains a binder resin for coating [C]. Organic solvents, liquid modified resins, pigments, curing catalysts, organic resin particles, ultraviolet absorbers, ultraviolet stabilizers, coating surface adjusters,
An antioxidant, a fluidity adjusting agent, a slipperiness imparting agent such as wax, a pigment dispersant, a silane coupling agent, and the like can be appropriately contained.

The coating composition of the present invention is usually an organic solvent type coating composition. In this case, an organic solvent which can dissolve or disperse each component of the coating can be used.
The above-mentioned organic solvents and the like which can be used when the copolymer resin [A] is subjected to solution polymerization can be used.

Examples of the liquid modifying resin include cellulose acetate butyrate, epoxy resin, polyester resin, alkyd resin, acrylic resin and the like, and are blended for the purpose of improving the properties of the coating film. The compounding amount of the liquid modifying resin is usually in the range of 30 parts by weight or less based on 100 parts by weight of the coating resin (A) and the coating binder resin [C].

Examples of the pigment include coloring pigments; aluminum powder, copper powder, nickel powder, stainless powder, chromium powder, mica-like iron oxide, titanium oxide-coated mica powder, iron oxide-coated mica powder, and brilliant graphite. Pigments; extender pigments such as barium sulfate, calcium carbonate, clay and silica; and rust preventive pigments such as strontium chromate, zinc chromate and zinc phosphate. As the coloring pigment, for example, organic red pigments such as cyanine blue, cyanine green, azo and quinacridone,
Organic yellow pigments such as benzimidazolone-based, isoindolinone-based, isoindoline-based and quinophthalone-based; titanium white, titanium yellow, bengara, carbon black,
Examples include inorganic color pigments such as graphite and various calcined pigments.

As the curing catalyst, for example, when the curing agent [B] is a melamine resin having a high degree of etherification such as a methyl etherified melamine resin, a strong acid such as paratoluenesulfonic acid and dodecylbenzenesulfonic acid or the like. It is preferred to use amine neutralized products of these strong acids. When the curing agent [B] is a polyisocyanate compound which may be blocked, dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, triethylamine, and diethanolamine are suitable as the curing catalyst.

The organic resin fine particles which can be optionally contained in the composition of the present invention are used for controlling the fluidity of the paint to prevent the occurrence of sagging and repelling of the paint film and for improving the properties of the paint film. The compound is blended for the purpose, is insoluble in the organic solvent used in the coating composition of the present invention, and may not be crosslinked in the particles, but is preferably crosslinked in the particles. The organic resin fine particles have an average particle diameter of 0.01.
It is preferably in the range of １1 μm, and those known per se can be used.

Examples of the ultraviolet absorber which can be optionally contained in the composition of the present invention include compounds such as benzophenone, benzotriazole, cyanoacrylate, salicylate and oxalic anilide. it can. Further, as the ultraviolet stabilizer,
Hindered amine compounds can be mentioned.

The coating composition of the present invention is used as a clear coating or as a colored coating composition (including a metallic coating and an interference color coating) containing various pigments such as a coloring pigment, a metallic pigment and an interference color pigment. In particular, it can be suitably used as a top coat for automotive coating.

The coating composition of the present invention can be applied to various objects to be coated by a conventional method.
By baking at a temperature of about 10 to 60 minutes, a cured coating film can be formed.

In the method of finishing the top coat according to the present invention, the above-mentioned coating composition of the present invention is applied as a top coat colored paint or a top coat clear paint in the method of finishing the top coat on an object to be coated.

The object to be coated with the coating composition of the present invention includes:
There is no particular limitation, for example, base materials such as metal, mortar, cement, plastics, and glass; and those obtained by subjecting these base materials to surface treatment and / or coating film formation. Among them, a metal substrate, particularly a substrate based on a steel plate, and a substrate based on plastics can be suitably used.

Examples of the steel sheet include cold-rolled steel sheet, hot-dip galvanized steel sheet, electrogalvanized steel sheet, aluminum-plated steel sheet, stainless steel sheet, copper-plated steel sheet, tin-plated steel sheet, lead-tin alloy-plated steel sheet (turn sheet); Zinc alloy-plated steel sheets such as zinc, aluminum-zinc, nickel-zinc and the like can be mentioned. Examples of the steel sheet subjected to the surface treatment include a steel sheet obtained by subjecting the above steel sheet to a chemical conversion treatment such as a phosphate treatment or a chromate treatment.

Further, as the object to which the coating film is formed,
Examples thereof include those in which a substrate is subjected to a surface treatment as necessary and a primer coating film is formed thereon, and those in which an intermediate coating film is formed on the primer coating film.

When the coating composition of the present invention is used as a top coat for automotive coating, a typical example of the object to be coated is to apply a primer to a chemically treated steel sheet by electrodeposition and, if necessary, to apply an intermediate coat. Painted materials, various plastic base materials (subjected to surface treatment, primer coating, intermediate coating, etc. as necessary), and composite members in which these materials are combined are exemplified.

The electrodeposition paint may be either an anionic type or a cationic type, but a cationic type having good anticorrosive properties is desirable. Known cationic electrodeposition paints can be used. For example, an aqueous paint containing a base resin having a hydroxyl group and a cationic group and a blocked polyisocyanate compound is preferable.

According to the finish method of the present invention, one coat and one bake (1C1B) and two coats and one bake
Bake (2C1B), 2 coats 2 bake (2C2B),
3 coats 1 bake (3C1B), 3 coats 2 bake (3
The above-mentioned coating composition of the present invention can be applied as a top-coating colored coating or a top-coat clear coating by a C2B) or 3-coat 3 bake (3C3B) method or the like, and a topcoat finish can be obtained. Acid resistance,
It is possible to form a top coat having excellent scratch resistance, chipping resistance, interlayer adhesion, sharpness and the like. Further, by using it as a top coating color coating, it is possible to obtain a coating film having further excellent color developing properties, and by using it as a top coating clear coating, it is possible to obtain a coating film having excellent transparency.

When the coating composition of the present invention is used as a top coating color coating for automobiles, for example, an uncured or cured intermediate coating applied to a primer coating such as an electrodeposition coating or a primer coating On the coating film, a dry film thickness is usually applied to be about 10 to 60 μm by means of, for example, electrostatic atomization coating (bell type or the like) or air spray coating.
By baking at a temperature of about 20 to 180 ° C. for about 10 to 60 minutes, a top-coating colored coating film can be formed. Further, on the uncured or cured topcoat colored coating film coated as described above, a topcoat clear paint is applied by means of, for example, electrostatic atomization coating (bell type or the like), air spray coating, or the like.
An overcoated multilayer coating film can be formed by coating and curing so that the dry film thickness is usually about 20 to 100 μm. Further, on the uncured or cured top clear coating film coated as described above, a top clear coating film may be further applied and cured so that the dry film thickness is usually about 20 to 100 μm.

Examples of the top clear coating composition applied on the top coating film include acrylic resins, vinyl resins, polyester resins, and alkyds having a crosslinkable functional group (for example, a hydroxyl group, an epoxy group, a carboxyl group, an alkoxysilane group, etc.). Resin, at least one base resin such as a urethane resin, and an alkyl etherified melamine resin, a urea resin, a guanamine resin, an optionally blocked polyisocyanate compound, an epoxy resin, and a carboxyl resin for crosslinking and curing the base resin. A clear top coating comprising at least one crosslinking agent such as a group-containing compound is suitable, and the mixing ratio of the base resin and the crosslinking agent is usually 50 to 90% by weight based on the total of the two. %,
It is desirable that the crosslinker component is 10 to 50% by weight.
In addition, a clear top coating contained in the coating composition of the present invention can also be suitably used.

When the coating composition of the present invention is used as an overcoat clear coating for automobiles, for example, on a primer coating such as an electrodeposition coating, or on an uncured or cured intermediate coating, or On a cured or cured topcoat colored coating film, or on an uncured or cured topcoat clear coating film, the dry film thickness is determined by means such as electrostatic atomization coating (bell type or the like) or air spray coating. Painted to a thickness of about 20 to 100 μm,
By heating for 〜60 minutes, a clear top coat can be formed.

[0091]

EXAMPLES Hereinafter, the present invention will be further clarified with reference to Production Examples, Examples, and Comparative Examples. Unless otherwise specified, “parts” and “%” mean “parts by weight” and “% by weight”, respectively.

Production Example 1 of Copolymer Resin Acrylic resin reaction tank equipped with a stirrer, a thermometer, a reflux condenser, etc. was charged with 60 parts of swazole 1000 (manufactured by Cosmo Oil Co., Ltd., aromatic solvent), n- 20 parts of butyl alcohol was charged, heated and stirred, and after reaching 115 ° C., a mixture of the following monomers and the like was added dropwise over 3 hours.

Styrene 41 parts n-butyl acrylate 10 parts lauryl methacrylate 10 parts 2-hydroxyethyl methacrylate 10 parts PLUXEL FM-3X (Note 1) 25 parts Dimethylaminoethyl methacrylate 1 part Light ester PM (Note 2) 3 parts 2, 2'-azobisisobutyronitrile 5 parts After the mixture of the above monomers is added dropwise, the mixture is further treated with 115 for 30 minutes.
After the temperature was maintained at 0 ° C., an additional catalyst solution, which was a mixture of 0.5 part of 2,2′-azobisisobutyronitrile and 10 parts of swazole, was added dropwise over 1 hour. After further stirring at 115 ° C. for 1 hour, the mixture was cooled. This was diluted with 10 parts of n-butyl alcohol to obtain a copolymer resin solution (A-1) having a solid content of 50%. The weight average molecular weight (Mw) of the obtained acrylic resin was 15,000, the hydroxyl value was 30 mgKOH / g, and the acid value was 16 mgKOH / g.

(Note 1) Praxel FM-3X: manufactured by Daicel Chemical Industries, Ltd., a trade name, methacrylic acid ester having a polyester chain with ε-caprolactone opened.
(Note 2) Light ester PM: manufactured by Kyoeisha Chemical Co., Ltd., trade name, phosphate group-containing polymerizable unsaturated monomer which is 2-methacryloyloxyethyl acid phosphate.

Production Examples 2 to 8 The same procedures as in Production Example 1 were carried out except that the composition of the mixture of monomers and the like dropped in the production of the copolymer resin solution was changed to the composition shown in Table 1 below. The reaction was carried out by the method to obtain each copolymer resin solution. In the production of these copolymer resin solutions, the composition of a mixture of monomers and the like to be dropped, the solid content concentration of the obtained copolymer resin solution, the weight average molecular weight (Mw) of the copolymer resin, the hydroxyl value and The acid value is shown in Table 1 below. The copolymer resin solutions obtained in Production Examples 5 to 8 are for comparison. The blending amounts in Table 1 are expressed in parts by weight. (Note) in the following Table 1 has the following meaning. (Note 3) Isostearyl acrylate: trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., long-chain branched alkyl acrylate.

[0096]

[Table 1]

Production Example 9 Production of Epoxy Group-Containing Acrylic Resin Hardener Solution (B-1) In an acrylic resin reaction vessel equipped with a stirrer, thermometer and reflux condenser, 40 parts of "Swazole 1000" and n-butyl alcohol 10 The mixture was heated and stirred, and after the temperature reached 140 ° C., a mixture of the following monomers and the like was added dropwise over 3 hours.

Styrene 30 parts n-butyl acrylate 10 parts n-butyl methacrylate 10 parts hydroxyethyl methacrylate 10 parts glycidyl methacrylate 40 parts t-butyl peroxy 2-ethylhexanoate 6 parts A mixture of the above monomers and the like is dropped. 14 minutes for 30 minutes
After maintaining at 0 ° C., an additional catalyst solution, which was a mixture of 0.5 part of 2,2′-azobisisobutyronitrile and 10 parts of swazole, was added dropwise over 1 hour. 1 at 140 ° C
After stirring for an hour, the mixture was cooled. This was diluted with 10 parts of n-butyl alcohol and diluted with a curing agent solution (B-B) which was an epoxy group-containing acrylic resin having a solid content of 55%.
1) was obtained. The weight average molecular weight (Mw) of the obtained acrylic resin was 8,000, and the hydroxyl value was 43 mgKOH /
g, epoxy equivalent was 355 g / equivalent.

Production Example 10 of Binder Resin (C) for Paint Production of Hydroxyl-Containing Acrylic Resin Solution 50 parts of xylol, n-butyl alcohol 20 were placed in an acrylic resin reaction tank equipped with a stirrer, thermometer, reflux condenser and the like.
The mixture was heated and stirred, and after the temperature reached 115 ° C., a mixture of monomers and the like shown in Table 2 below was added dropwise over 3 hours. After dropping the mixture of the above monomers and the like, the mixture was kept at 115 ° C. for another 30 minutes, and then an additional catalyst solution which was a mixture of 0.5 part of 2,2′-azobisisobutyronitrile and 10 parts of xylol was added. It took 1 hour to drop. After further stirring at 115 ° C. for 1 hour, the mixture was cooled. This was diluted with 5 parts of n-butyl alcohol to obtain a hydroxyl group-containing acrylic resin solution (C1-1) having a solid content concentration of 55%. The weight average molecular weight (Mw) of the obtained acrylic resin was 12,000,
The hydroxyl value was 108 mgKOH / g.

Production Examples 11 to 12 Production of Hydroxyl-Containing Acrylic Resin Solution In Production Example 10, except that the raw materials used were as shown in Table 2 below, a hydroxyl-containing acrylic resin solution (C1- 2) and (C1-3) were obtained.

Production Example 13 Production of High Acid Value Acrylic Resin A high acid value acrylic resin solution (C3-1) was produced in the same manner as in Production Example 10 except that the raw materials used were as shown in Table 2 below. ) Got.

[0102]

[Table 2]

Production Example 14 Production of Hydroxy Group-Containing Polyester Resin Solution In a reaction vessel equipped with a stirrer, thermometer, rectification tower, nitrogen inlet tube, reflux condenser, etc., 2 mol of isophthalic acid, 4 mol of hexahydrophthalic acid, 3 mol of adipic acid, 3 mol of neopentyl glycol, 5 mol of 1.6-hexanediol, and 2 mol of trimethylolpropane were charged, and heated and stirred.
After reaching 0 ° C, the temperature was raised to 235 ° C over 3 hours.
After aging for 1.5 hours after raising the temperature, the rectification column was replaced with a reflux condenser, 1.4 mol of xylene was introduced, and the reaction was carried out under reflux. The reaction was allowed to proceed at 235 ° C. for 8 hours, and 1000 parts of swazole were added to obtain a hydroxyl group-containing polyester resin solution (C2-1) having a solid concentration of 60%.

Production Examples 15 to 16 Production of Hydroxyl-Containing Polyester Resin Solution In Production Example 14, except that the raw materials used were as shown in Table 3 below, a hydroxyl-containing polyester resin solution (C2- 2) and (C2-3) were obtained.

Production Example 17 Production of High Acid Value Polyester Resin Solution In Production Example 14, except that the raw materials used were as shown in Table 3 below, a high acid value polyester resin solution (C4- 1) was obtained.

[0106]

[Table 3]

Production Example 1 of Clear Coating Composition The 50% acrylic resin solution (A-1) 15 obtained in Production Example 1
8 parts (79 parts in solid content), "Desmodur N350
0 "(trade name, manufactured by Sumitomo Bayer Urethane Co., blocked polyisocyanate compound, solid content 100%) 21 parts,
"Disparon LC-955" (trade name, a surface conditioner manufactured by Kusumoto Kasei Co., Ltd., active ingredient 10%) 0.5 part (active ingredient amount 0.05 part) was mixed to obtain a clear coating composition. .

Examples 2 to 12 and Comparative Examples 1 to 8 Each coating composition was obtained in the same manner as in Example 1, except that the composition was changed as shown in Table 4 below.

(Note) in Table 4 below has the following meanings, respectively. (Note 4) Nikarac MS25: trade name, manufactured by Sanwa Chemical Co., Ltd., a butyl etherified melamine resin solution having a solid content of about 70%. (Note 5) Nacure 5225: Nacure 5225,
Trade name, manufactured by King Industries of the United States, a curing catalyst solution which is a solution of an amine neutralized sulfonic acid compound, about 25% of an active ingredient. (Note 6) TBAB: tetrabutylammonium bromide.

Using each of the clear coating compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 8, each test coated plate was prepared according to the following test coated plate preparation method (1).

Preparation of Test Coated Plate (1) An epoxy resin-based cationic electrodeposition paint was coated on a 0.8 mm-thick cold-rolled dull steel plate subjected to a chemical conversion treatment with zinc phosphate to a dry film thickness of about 20 μm. On the electrodeposited coating film baked and baked, a polyester resin intermediate coating for automobiles was applied and baked so as to have a dry film thickness of about 20 μm. This coated plate is water-dried with # 400 sandpaper, drained and dried,
Degreasing with petroleum benzine. Next, the clear coating compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 8 were adjusted to have a coating viscosity of 25 seconds (Ford Cup # 4, 25 ° C.) on this degreased plate to give a dry film thickness of about 40 μm. The coating was carried out as described above, and left standing at room temperature for about 3 minutes. After setting, the plates were baked in an electric hot air dryer at 140 ° C. for 30 minutes to prepare each test coated plate.

Various tests were performed on these test coated plates based on the following test methods. Table 4 below shows the test results.
Shown in

Test Method Coating Appearance: The finished appearance of the coating film was comprehensively investigated from the glossiness and the feeling of holding, and evaluated according to the following criteria. ：: good, △: bad, ×: extremely poor.

Adhesion: JIS K-5400 8.5.
2 (1990) According to the crosscut-tape method, 11 parallel vertical and horizontal straight lines are drawn at 1 mm intervals on the surface of the coating film of the test plate so as to reach the substrate with a cutter knife, and the distance is 1 mm. 100 × 1 mm squares were created. A cellophane adhesive tape was adhered to the surface, and the degree of peeling of the squares when the tape was abruptly peeled was observed and evaluated according to the following criteria. ：: 90 or more squares of the coating film remained, Δ: the coating film was peeled, and the number of remaining squares was 50 or more and 90
Less than, ×: The coating film peeled off, and the number of remaining squares was less than 50.

Acid resistance: 0.5 cc of artificial rain having the following composition was dropped on the coating film of the test plate, heated on a hot plate heated to 80 ° C. for 30 minutes, washed with water, and the coated surface was visually observed. Then, the following criteria were used for evaluation. ：: No change was observed on the painted surface, Δ: Whitening and swelling were not observed on the painted surface, but a step was observed at the boundary, ×: Whitening or swelling was observed on the painted surface, 1 mg / g NaNO ₃ aqueous solution 1
9.6 g, 1 mg / g KNO ₃ aqueous solution 5.2 g, 1 m
3.7 g / g CaCl ₂ .2H ₂ O aqueous solution, 1 mg / g
8.2 g of MgSO ₄ .7H ₂ O aqueous solution, 73.3 g of 1 mg / g (NH ₄ ) ₂ SO ₄ aqueous solution, 0.1N H ₂ SO
₄ aqueous solution 30.0 g, 0.1N HNO ₃ aqueous solution 20.0
g, 10.0 g and 1 mg /
blended NaF solution 4.7g of g concentration, the pH H ₂ S
It was adjusted to 1.0 with O ₄ .

Car wash abrasion resistance: The state of the painted surface of the coated plate was observed after the automobile having the test coated plate attached to the roof was washed 15 times with a car washer. The car washer was manufactured by Yasui Sangyo
20FWRC "and evaluated according to the following criteria. ：: No scratch is found by visual observation. Δ: Scratch is slightly observed, but the degree is very slight. ×: Scratches are conspicuous by visual observation.

Chipping resistance: Using a gravelometer (manufactured by Q Panel), apply 100 g of No. 7 crushed stone to
At 20 ° C at 5 ° angle, air pressure 4kg / cm2
To give an impact to the coating film, observe the state of the coated surface, and evaluate it according to the following criteria. ○: Part of the clear coating film is scarcely damaged by impact,
No peeling of the electrodeposited film was observed at all. Δ: A slight damage due to impact was observed in the clear coating film, and slight peeling was also observed on the electrodeposited surface.

X: The clear coating film is considerably scratched by impact, and the electrodeposited surface is also considerably peeled.

Solvent resistance: In a room at 20 ° C., about 1 kg was applied to the painted surface with gauze impregnated with methyl ethyl ketone.
After applying a load of / cm ² and reciprocating 50 times over a length of about 5 cm, the state of the coated surface was visually evaluated according to the following criteria. ：: no change is observed on the coated surface, Δ: scratch is recognized on the coated surface, ×: whitening or swelling of the coated film is recognized.

Impact resistance: JIS K-5400
According to 3.2 (1990) Dupont impact resistance test,
With the coating surface of the test coated plate facing upward, the test is performed under the conditions of a drop weight of 500 g and a tip diameter of the hammer of 1/2 inch, and the maximum drop weight height that does not cause damage to the coating film is indicated. The maximum value is 50 cm.

[0121]

[Table 4]

[0122]

[Table 5]

Preparation of Pigment Dispersion Paste Preparation Example 1 In a wide-mouthed glass bottle, 200 parts of the 50% copolymer resin solution obtained in Production Example 1, 80 parts of toluene, 20 parts of 3-methoxybutyl acetate and "MONARCH1300" (Monarch 1300, Product name, USA USA, manufactured by Cabot,
60 parts of a carbon black pigment), glass beads having a diameter of about 1.3 mmΦ are added and mixed as a dispersion media, and the pigment is dispersed by a paint shaker for 4 hours. -1)
I got The pigment particle size (gum) in this pigment paste was 10 μm or less.

Preparation Examples 2 to 7 Each pigment paste was obtained in the same manner as in Preparation Example 1, except that the composition of the resin solution, solvent and pigment was changed as shown in Table 5 below. The pigment particle size (grain) in each of the obtained pigment pastes was 10 μm or less. Preparation Example 5
The pigment paste obtained in 7 is for comparison.

(Note) in Table 5 has the following meanings. (Note 7) Cyanine blue 5206: trade name, manufactured by Dainichi Seika Co., Ltd., copper phthalocyanine blue pigment.

Each pigment dispersion paste obtained in Preparation Examples 1 to 7 was subjected to a performance test based on the following test method. The test results are shown in Table 5 below.

Test method Coating appearance: Each pigment-dispersed paste was 100 × 200 mm
Was applied by a bar coater so as to have a dry film thickness of 15 μm, and baked at 140 ° C. for 30 minutes. The degree of turbidity of the coating film formed on the film was visually evaluated according to the following criteria. ：: uniform and no turbidity Δ: slight turbidity observed X: considerable turbidity observed

Gloss: JIS K5400 7.6 (19
90), the 60 ° specular reflectance of each coating film was measured.

Transparency: Using a turbidimeter (COH-300), the light transmittance (%) was measured as shown below. Light transmittance (%) = 100 × [1− (scattered light intensity / irradiation light intensity)] Viscoelastic properties: Viscosity (Pa · sec, Pascal) using a viscoelasticity analyzer “MR-300” (manufactured by Rheology).・
Second) and the yield value (dyn / cm ² ).

[0130]

[Table 6]

Preparation of Colored Paint Composition Example 13 90 parts (40 parts in solid content) of the pigment dispersion paste (D-1) obtained in Preparation Example 1 and the 55% hydroxyl group-containing acrylic resin obtained in Production Example 10 ( C1-1) 100 parts (solid content of 5
5 parts), 35.7 parts of “Nicalac MS25” (25 parts in solid content), 0.4 parts of “Nacure 5225” and 0.5 parts of “Dispalon LC-955” were mixed to obtain a colored coating composition.

Examples 14 to 16 and Comparative Examples 9 to 11 The pigment dispersion pastes obtained in Preparation Examples 2 to 7 were used and the composition was as shown in Table 6 below.
In the same manner as in above, each colored coating composition was obtained.

Examples 13 to 16 and Comparative Examples 9-1
Using each of the colored coating compositions obtained in 1, each test coated plate was prepared based on the following test coated plate preparation method (2).

Method of preparing test coated plate (2) An epoxy resin-based cationic electrodeposition paint was coated on a 0.8 mm thick cold-rolled dull steel plate subjected to a zinc phosphate chemical conversion treatment so that the dry film thickness was about 20 μm. On the electrodeposited coating film baked and baked, a polyester resin intermediate coating for automobiles was applied and baked so as to have a dry film thickness of about 20 μm. This coated plate is water-dried with # 400 sandpaper, drained and dried,
Degreasing with petroleum benzine. Then, on the degreased plate, each of the colored coating compositions was coated with a coating having a coating viscosity of 25 seconds (Ford Cup #
(4, 25 ° C.), coated to a dry film thickness of about 30 μm, allowed to stand at room temperature for about 5 minutes, set, and then cured with a thermosetting acrylic / melamine resin clear product manufactured by Kansai Paint Co., Ltd. (Paint Co., Ltd., manufactured by Kansai Paint Co., Ltd.) was applied so as to have a dry film thickness of about 40 μm, and baked at 140 ° C. for 30 minutes with an electric hot air drier to prepare each test coated plate.

Various tests were carried out on these test coated plates based on the same test method as that for the test coated plate obtained in the method (1) for preparing the test coated plate. The test results are shown in Table 6 below. However, the evaluation criteria for chipping resistance are as follows.

：: Part of the clear coating film was scarcely damaged by impact, and peeling of the electrodeposited film was not observed at all. Δ: Damage caused by impact was observed on the clear coating film and the colored coating film. Slight peeling is also observed on the contact surface.

C: Many scratches due to impact were observed in the colored coating film, and considerable peeling was also observed on the electrodeposited surface.

[0138]

[Table 7]

[0139]

According to the coating composition of the present invention, acid resistance,
Excellent coating performance such as car wash abrasion resistance, chipping resistance, interlayer adhesion and the like, and a coating film with excellent finished appearance such as sharpness can be formed. The colored coating composition of the present invention containing a pigment is excellent in pigment dispersibility and color development.
The clear coating composition of the present invention is also excellent in transparency.

Further, a coating film excellent in the above-mentioned coating film performance and finished appearance can be formed by the top coat finishing method of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 133/04 C09D 133/04 157/10 157/10 157/12 157/12 163/00 163/00 167 / 00 167/00 F-term (reference) 4J034 BA03 DA01 DA03 DA05 DA06 DA10 DB03 DF14 GA15 GA33 GA36 HD03 HD05 HD06 HD12 4J038 CC021 CC022 CC071 CC072 CC081 CC082 CG001 CG002 CG141 CG142 CG161 CG162 CH031 DB03 DD001 DB001 CH041 DG302 GA03 GA06 GA08 GA09 GA13 GA14 KA03 KA06 KA08 NA03 NA11 PB07 PC02 4J100 AB02P AB03P AB04P AL03P AL04P AL08Q AL08R AL08S AL09Q AL11P AM02P AM41S BA03Q BA08Q BA31S BA33S BA56S BA63R CA06 DA30 FA03

Claims (9)

[Claims] 1. [A] (a) a polymerizable unsaturated monomer containing at least one hydrophilic functional group selected from an amino group, a quaternary ammonium base and a sulfonic acid group;
1 to 10% by weight, (b) 6 to 50% by weight of a hydroxyl group-containing polymerizable unsaturated monomer, (c) 0.1 to 1 of a phosphate group-containing polymerizable unsaturated monomer
A resin having a hydroxyl value of 30 to 200 mgKOH / g obtained by copolymerizing a monomer mixture consisting of 0% by weight and (d) 30 to 90% by weight of another polymerizable unsaturated monomer; and [B] a curing agent. A coating composition comprising: 2. At least a part of the other polymerizable unsaturated monomer (d) has the following formula (I): (Wherein R ¹ and R ² are the same or different and each have 1 carbon atom)
It represents 6 alkyl group, R ³ is (meth) acrylic acid ester having a branched alkyl group having 8 to 24 carbon atoms having a portion indicated by a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) The coating composition according to claim 1, which is a monomer. 3. The coating composition according to claim 1, further comprising a coating resin [C] other than the copolymer resin [A]. 4. The coating binder resin [C] is at least one resin selected from a hydroxyl group-containing acrylic resin and a hydroxyl group-containing polyester resin, and the curing agent [B] is an amino resin and an optionally blocked poly. The coating composition according to claim 3, wherein the coating composition is at least one curing agent selected from isocyanate compounds. 5. The coating binder resin [C] is at least one carboxyl group-containing resin selected from a high acid value polyester resin and a high acid value acrylic resin, and the curing agent [B] is an epoxy resin and an epoxy group. 4. The coating composition according to claim 3, wherein the coating composition is at least one resin selected from acrylic resins. 6. The coating composition according to claim 1, further comprising a pigment. 7. The coating composition according to claim 6, wherein the coating composition is formed using a pigment dispersion paste containing the copolymer resin [A], a pigment, and, if necessary, a solvent. 8. A method for finishing a top coat on an object to be coated, wherein the coating composition according to claim 1 is applied as a top coat colored enamel paint or a top coat clear paint. 9. A method for finishing a top coat on an object to be coated, wherein the coating composition according to claim 6 or 7 is applied as a top coat colored enamel paint.