JP3243165B2 - Curable resin composition, coating composition and coating film forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable resin composition suitably used for an automotive topcoat and a coil coating.

[0002]

2. Description of the Related Art It is common to use a combination of a hydroxyl group-containing polymer and a melamine resin curing agent as a binder used as a top coating for automobiles. However, a cured film obtained by using such a melamine resin as a curing agent generally has poor acid resistance. Therefore, such a coating is particularly susceptible to deterioration by acid rain, which has recently become a problem, and causes a defect in appearance.

It is considered that the film obtained by using a melamine resin as a curing agent has poor acid resistance due to triazine nuclei in the melamine resin. Therefore, as long as the melamine resin is used as a curing agent, the disadvantage of poor acid resistance cannot be solved.

[0004] In JP-A-2-45577 and JP-A-3-287650, a novel coating composition which does not use a melamine resin is proposed. This coating composition has good acid resistance because an ester bond formed by reacting an acid group and an epoxy group is used as a crosslinking point.

However, since this curing system has a high functional group concentration and a high viscosity, it is difficult to produce a high solid type high solid type coating, and it is necessary to use a large amount of a solvent. On the other hand, in recent years, there has been a demand for a high solid paint that emits a small amount of solvent into the atmosphere in order to reduce adverse effects on the environment.

[0006] Japanese Patent Application Laid-Open No. 6-166741 discloses a high solid coating composition using a silicone polymer. However, in these references, the hydroxyl functional silicone polymer is reacted with an acid anhydride group-containing compound to impart acid functionality in order to introduce it into the coating composition. As a result, there is a disadvantage that the amount of the functional group cannot be increased, the resin Tg decreases, and the Tg of the coating film does not increase.

On the other hand, Japanese Patent Publication No. 6-41575 discloses a high solid coating composition containing (a) a polyepoxide and (b) a polyester polycarboxylic acid. However, the solid content of the coating composition is not sufficiently high from the viewpoint of not adversely affecting the environment, and the formed coating film has poor acid resistance.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a high solid content for forming a film having excellent resistance to acid rain, scratch resistance and appearance. An object of the present invention is to provide a curable resin composition, a high solid paint composition, and a method for forming a coating film using the same.

[0009]

According to the present invention, there are provided (a) an average of two or more carboxyl groups in one molecule, and an acid value of 5 to 300 mgKOH / g.
And (b) an acid value obtained by reacting a polyester polyol having three or more hydroxyl groups with an acid anhydride group-containing compound, from 10 to 70% by weight of an acrylic polycarboxylic acid having a number average molecular weight of from 500 to 8000. 350mgKOH / g (solid content), number average molecular weight 400 ~ 3500 and weight average molecular weight / number average molecular weight
A high solids curable resin composition comprising 5 to 70% by weight of a polyester polycarboxylic acid having 1.8 or less; and (C) 10 to 80% by weight of a polyepoxide having an epoxy equivalent of 50 to 700 and a number average molecular weight of 200 to 10,000. (However, component (a) ~
The amount of (c) is based on the weight of the total solids in the curable resin composition. ), Whereby the object is achieved.

The acrylic polycarboxylic acid (a) used in the curable resin composition of the present invention has an average of two or more carboxyl groups in one molecule, an acid value of 5 to 300 mgKOH / g, preferably 25 to 300 mgKOH / g.
An acrylic polycarboxylic acid having 250 mgKOH / g, more preferably 50-200 mgKOH / g, and a number average molecular weight of 500-8000, preferably 800-6000, more preferably 1500-4000.

The acrylic polycarboxylic acid has a carboxyl group-containing ethylenically unsaturated monomer of 5 to 80% by weight.
And 20 to 95% by weight of an ethylenically unsaturated monomer having no carboxyl group by a known method. In the copolymerization, for example, an azo-based initiator or a peroxide-based initiator as a radical polymerization initiator is added in an amount of 0.1 to 100 parts by weight of the total of the ethylenically unsaturated monomers.
It is used in an amount of 5 to 20 parts by weight and has a polymerization temperature of 80 to 200.
The polymerization can be carried out at normal temperature or under pressure for 3 to 10 hours at ℃. At that time, a chain transfer agent, a coloring inhibitor, and the like may be added.

Specific examples of the carboxyl group-containing ethylenically unsaturated monomer include, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, and adducts thereof with ε-caprolactone (for example, “Aronix manufactured by Toa Gosei Chemical Co., Ltd.). M-5300 ”), and the addition of an ethylenically unsaturated monomer having a hydroxyl group represented by the formula (I) and an acid anhydride group-containing compound, and the addition of an acid anhydride group-containing ethylenically unsaturated monomer and a monoalcohol. Things. These can be used alone or in combination of two or more.

The compound having an acid anhydride group is at room temperature to 150 ° C.
The carboxy functionality is provided by a half-esterification reaction with hydroxyl groups under normal reaction conditions such as normal pressure. Here, a cyclic group having 4 to 12, particularly 8 to 10 carbon atoms
It is preferable to use an acid anhydride group-containing compound having a (unsaturated or saturated) group. This is because the use of such a compound improves the compatibility of the obtained resin. Specific examples of preferred acid anhydride group-containing compounds include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, trimellitic anhydride, succinic anhydride, and the like.

Specific examples of the acid anhydride group-containing ethylenically unsaturated monomer used herein include itaconic anhydride, maleic anhydride and citraconic anhydride.

Specific examples of the monoalcohol used here include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, and n-butanol.
Hexyl alcohol, lauryl alcohol, methyl cellosolve, ethyl cellosolve, methoxypropanol, ethoxypropanol, furfuryl alcohol, dimethylaminoethanol, diethylaminoethanol, acetol, allyl alcohol and propargyl alcohol.

Specific examples of the ethylenically unsaturated monomer having no carboxyl group include styrene, α-methylstyrene, pt-butylstyrene and (meth) acrylate.
(For example, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) propyl acrylate, (meth) acrylic acid
n-, i-, and t-butyl, 2-ethylhexyl (meth) acrylate and lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate), Shell Corporation's VeoVa-9 And VeoVa-10. When styrene and a styrene derivative are used as the ethylenically unsaturated monomer having no carboxyl group, it is preferably used in an amount of 5 to 40% by weight.

Preferably, as the acrylic polycarboxylic acid (a) of the curable resin composition of the present invention, an acrylic polycarboxylic acid (a) having a carboxyl group and a carboxylic ester group on adjacent carbons is used. . This is because the acid resistance of the obtained coating film is improved. Acrylic polycarboxylic acid having carboxyl group and carboxylic ester group
(a) is obtained, for example, by reacting an acrylic polyanhydride (a) (i) with a monoalcohol (a) (ii).

The acrylic polyanhydride (a) (i) is used in an amount of 15 to 40% by weight, preferably 15 to 35% by weight, of the ethylenically unsaturated monomer (a) (i) (1) having an acid anhydride group. It is obtained by copolymerizing the ethylenically unsaturated monomer (a) (i) (2) having no acid anhydride group with 60 to 85% by weight, preferably 65 to 85% by weight. Acid anhydride group-containing ethylenically unsaturated monomer (a) (i)
If the amount of (1) is less than 15% by weight, the curability will be insufficient, and if it exceeds 40% by weight, the resulting coating film will be too hard and brittle, and the weather resistance will be insufficient. Specific examples of the acid anhydride group-containing ethylenically unsaturated monomer (a) (i) (1) include those already described.

The ethylenically unsaturated monomer (a) (i) (2) having no acid anhydride group is not particularly limited as long as it does not adversely affect the acid anhydride group. It is preferably a monomer having 3 to 15 carbon atoms, particularly 3 to 12 carbon atoms.

An ethylenically unsaturated monomer having no acid anhydride group by mixing two or more ethylenically unsaturated monomers.
(a) (i) (2) can also be used. This is because it is effective for improving the compatibility between the resins. Specifically, the above-mentioned monomers are exemplified as the ethylenically unsaturated monomer having no carboxyl group.

Monomers having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid and maleic acid are also ethylenically unsaturated monomers having no acid anhydride group.
It can be used as (a) (i) (2). Among them, adducts of these with ε-caprolactone (for example, Aronix M-530)
When a long-chain carboxylic acid monomer having a spacer portion of about 5 to 20 carbon atoms between an ethylenically unsaturated group and a carboxyl group such as 0) is used, the scratch resistance of the coating film is improved, and preferable.

For example, the hydroxyl group-containing ethylenically unsaturated monomer and the acid anhydride group-containing compound may be used in a molar ratio of hydroxyl group to acid anhydride group of 1 / 0.5 to 1 / 1.0, preferably 1 / 0.8 to 1 / 1.0. A carboxyl group-containing ethylenically unsaturated monomer obtained by performing a half-esterification reaction in an amount of a certain amount is converted to an ethylenically unsaturated monomer having no acid anhydride group.
It can be used as (a) (i) (2). When the molar ratio is 1 / 0.5 or more, the viscosity of the polymer becomes high, resulting in poor workability. 1 / 1.0
When the content is less than the above range, an excess of the acid anhydride group-containing compound remains, and the water resistance of the coating film decreases.

The hydroxyl group-containing ethylenically unsaturated monomer used herein preferably has 5 to 23 carbon atoms,
More preferably, it is 13. If the chain length is too short, flexibility near the cross-linking point is lost, so that the chain becomes too hard, and if it is too long, the molecular weight between cross-linking points becomes too large. In general, the expression [Wherein, R is a hydrogen atom or a methyl group, and X is (Wherein, Y is a linear or branched alkylene group having 2 to 8 carbon atoms, m is an integer of 3 to 7, and q is an integer of 0 to 4), or ,formula Wherein R is a hydrogen atom or a methyl group, and n is 2 to 50
Is an integer. ). And a hydroxyl group-containing ethylenically unsaturated monomer having a structure represented by the following formula: Specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid Compounds such as 6-hydroxyhexyl and their reactants with ε-caprolactone and (meth) acrylic acid with a large excess of diols (e.g., 1,4 butanediol, 1,6 hexanediol, polyethylene glycol, polypropylene glycol) Compounds that can be prepared by esterification of

Such compounds are commercially available, for example, 4-hydroxybutyl acrylate “4HBA” and 4-hydroxybutyl methacrylate “4HBM” manufactured by Mitsubishi Chemical Corporation.
A "and" Placcel FM1 "and" Placcel FA1 "manufactured by Daicel Chemical Industries, Ltd. As a propylene oxide monomer, "Blemmer PP-" manufactured by NOF Corporation
The “1000”, “Blemmer PP-800” and the ethylene oxide monomer include “Blemmer PE-90”.

Specific examples of the acid anhydride group-containing compound used herein include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, trimellitic anhydride, succinic anhydride and the like. Is mentioned.

The half-esterification reaction between the hydroxyl group-containing ethylenically unsaturated monomer and the acid anhydride group-containing compound is carried out at a temperature of from room temperature to 150 ° C. according to a conventional method.

Acid anhydride group-containing ethylenically unsaturated monomer
Copolymerization of (a) (i) (1) and an ethylenically unsaturated monomer having no acid anhydride group (a) (i) (2) is a known method such as solution polymerization such as radical polymerization. For example, the polymerization can be carried out at a polymerization temperature of 100 to 200 ° C. and a polymerization time of 3 to 8 hours under normal pressure or under pressure. As the initiator, an azo-based or peroxide-based initiator is suitably used.
Other additives such as chain transfer agents may also be used.

The number average molecular weight of the obtained polymer is 500 to 8
000, and preferably 800 to 6000, particularly preferably 1500 to 4000. If the number average molecular weight exceeds 8000, the compatibility between the resins will decrease, and the appearance will decrease. When the number average molecular weight is less than 500, the curability of the resin composition becomes insufficient. On average, at least two, preferably two, polymers are obtained per molecule.
When the number of the acid anhydride groups contained in one molecule having up to 15 acid anhydride groups is less than 2, the curability of the resin composition becomes insufficient. If it exceeds 15, it becomes too hard and brittle, and the weather resistance is insufficient.

Next, the obtained acrylic polyanhydride is obtained.
(a) (i), the acid anhydride group and the hydroxyl group in a molar ratio of 1/10 to 1 /
1, preferably 1/5 to 1/1, more preferably 1 / 2.0 to 1/1 by reacting with monoalcohol (a) (ii) in an amount of carboxyl group and carboxylic ester group To prepare an acrylic polycarboxylic acid (a) having 1/10
If it is less than, excessive alcohol is too much, which causes a fire during curing, and if it exceeds 1/1, unreacted anhydride groups remain,
Poor storage stability.

Monoalcohol (a) (ii) usable in the present invention
Preferably has from 1 to 12, especially from 1 to 8, carbon atoms. This is because the alcohol volatilizes during heating and is good for regenerating the acid anhydride group. Specific examples of the preferably used monoalcohol include those already listed. Particularly preferred are acetol, furfuryl alcohol,
Allyl alcohol, propargyl alcohol, ethanol and methanol.

The resulting acrylic polycarboxylic acid (a) having a carboxyl group and a carboxylic acid ester group has an acid value of 5 to 300 mgKOH / g, preferably 50 to 250 mgKOH / g. If the acid value is less than 5 mgKOH / g, the curability will be insufficient and 300
If it exceeds mgKOH / g, the storage stability becomes poor, which is not preferable.

The acrylic polycarboxylic acid (a) component is used in an amount of 10 to 70 based on the weight of the total solids in the curable resin composition.
% By weight, preferably 15 to 50% by weight, more preferably 20 to
It can be incorporated into the curable resin composition in an amount of 45% by weight. If the blending amount of the acrylic polycarboxylic acid (a) component is less than 10% by weight, the acid resistance of the obtained coating film is lowered, and if it exceeds 70% by weight, the coating film becomes too hard.

The polyester polycarboxylic acid (b) used in the curable resin composition of the present invention is obtained by half-esterifying a polyester polyol having three or more hydroxyl groups and an acid anhydride group-containing compound.

In the present specification, the “polyester polyol” refers to a polyhydric alcohol having two or more ester bond chains. The polyhydric alcohol refers to an alcohol having two or more hydroxyl groups.

The polyester polyol used here is:
Reacts with an acid anhydride group containing compound to provide a polyester polycarboxylic acid having more than one acid functionality per molecule and the following properties:

Generally, such a polyester polyol is prepared by condensing a linear aliphatic dicarboxylic acid with a low molecular weight polyhydric alcohol having at least 3 hydroxyl groups and having 3 to 16 carbon atoms. By introducing a linear aliphatic group into the low molecular weight polyhydric alcohol, the resulting coating film is given flexibility and the impact resistance is improved.

The low molecular weight polyhydric alcohol which can be used includes trimethylolpropane, trimethylolethane,
1,2,4-butanetriol, ditrimethylolpropane,
Examples include pentaerythritol, dipentaerythritol, glycerin and mixtures thereof.

Examples of the dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid and mixtures thereof. And dibasic acids. Also, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hymic anhydride, trimellitic anhydride, methylcyclohexentricarboxylic anhydride,
Acid anhydride group containing compounds such as pyromellitic anhydride and mixtures thereof may also be used.

The polyester polyol is synthesized by a usual esterification reaction. That is, the polyester is formed by a dehydration condensation reaction between a polyhydric alcohol and a polybasic acid or an esterification by a reaction between the polyhydric alcohol and an acid anhydride group-containing compound, and further a dehydration reaction between an alkyl component. By such an operation, an oligomer of a polyester polyol having a relatively low molecular weight is obtained, and a high-solid resin composition is provided.

Particularly preferred polyester polyols for use in the present invention are obtained by adding a lactone compound such as ε-caprolactone to a low molecular weight polyhydric alcohol to extend the chain. This is because the molecular weight distribution becomes sharp, so that the resin composition can be further made into a high solid, and a coating film excellent in weather resistance and water resistance can be obtained.
In this case, particularly preferably used low molecular weight polyhydric alcohols include trimethylolpropane, ditrimethylolpropane, pentaerythritol and the like.

The "lactone compound" used in the present invention has an oxygen atom in the ring, and reacts with a nucleophilic reagent to open the ring.
Any cyclic compound that generates a hydroxyl group at the terminal may be used. Preferred lactone compounds have 4 to 7 carbon atoms. This is because a ring-opening addition reaction easily occurs.

Specific examples include ε-caprolactone, γ-caprolactone, γ-valerolactone, δ-valerolactone, γ-butyrolactone, etc., preferably ε-caprolactone, γ-valerolactone and γ-butyrolactone. Used.

The chain extension can be carried out under the same conditions as in the usual ring-opening addition reaction. For example, a polyester polyol having a chain extended from a low-molecular-weight polyhydric alcohol can be obtained by reacting in a suitable solvent or without a solvent at a temperature of 80 to 200 ° C. within 5 hours. A tin catalyst or the like may be used.

At this time, the molar amount of the lactone compound is 0.2 to 10 times, preferably 0.25 to 5 times, more preferably 0.1 to 5 times the molar amount of the low molecular weight polyhydric alcohol OH group.
3 to 3 times the amount. When the molar amount of the lactone compound is less than 0.2 times the molar amount of the OH group, the resin becomes hard and the impact resistance of the coating film decreases, and when it exceeds 10 times, the hardness of the coating film decreases.

The polyester polycarboxylic acid (b) used in the curable resin composition of the present invention has an acid value of 50 to 350, preferably
100-300, more preferably 150-250 mg KOH / g (solid content) and number average molecular weight 400-3500, preferably 500-2500, more preferably 700-2000, weight average molecular weight / number average molecular weight
It has 1.8 or less, preferably 1.5 or less, more preferably 1.35 or less.

When the acid value exceeds 350, the viscosity of the resin composition becomes too high, and the solid content of the resin composition is lowered. When the acid value is less than 50, the curability of the resin composition becomes insufficient. When the molecular weight exceeds 3,500, the viscosity of the resin composition becomes too high, which makes it difficult to handle, and causes a decrease in the solid concentration of the resin composition.When the molecular weight is less than 400, the curability of the resin composition is insufficient or the coating film is insufficient. Decreases the water resistance. If the weight average molecular weight / number average molecular weight exceeds 1.8, the water resistance or weather resistance of the coating film decreases.

The half esterification reaction between the polyester polyol and the acid anhydride group-containing compound is carried out by phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
The reaction can be carried out using an acid anhydride group-containing compound such as 4-methylhexahydrophthalic anhydride, trimellitic anhydride and succinic anhydride under ordinary reaction conditions such as room temperature to 150 ° C. and normal pressure. However, it is not necessary to modify all the hydroxyl groups of the polyester polyol into carboxyl groups, and the hydroxyl groups may be left.

The polyester polycarboxylic acid having a hydroxyl group simultaneously provides a carboxyl group and a hydroxyl group on the surface of the coating film, and thus, for example, when recoated, is superior to a polyester polycarboxylic acid having no hydroxyl group. This is because it provides adhesion.

In that case, the polyester polycarboxylic acid
(b) may have a hydroxyl value of 150 mgKOH / g (solid content) or less, preferably 5 to 100 mgKOH / g, more preferably 10 to 80 mgKOH / g. When the hydroxyl value exceeds 150 mgKOH / g, the water resistance of the coating film decreases.

The polyester polycarboxylic acid having a hydroxyl group and a carboxyl group can react with and bind to both the polyepoxide (c) and the acrylic polycarboxylic acid (a), as described later. A membrane can be obtained. Those having an average of 0.1 or more hydroxyl groups in one molecule are preferred.

In general, it is desirable that the molar amount of the acid anhydride group of the acid anhydride group-containing compound is 0.2 to 1.0 times, particularly 0.5 to 0.9 times the molar amount of the OH group of the polyester polyol. If the molar amount of the acid anhydride group is less than 0.2 times the molar amount of the OH group, the curability of the obtained resin composition will be insufficient.

The polyester polycarboxylic acid (b) component comprises:
5 to 5 based on the weight of the total solids in the curable resin composition
70% by weight, preferably 5-50% by weight, more preferably 10%
-40% by weight. When the amount of the polyester polycarboxylic acid is less than 5% by weight, the solid content concentration of the obtained coating does not increase, and when it exceeds 70% by weight, the weather resistance of the obtained coating film decreases.

The polyepoxide (c) used in the curable resin composition of the present invention is a compound having an average of two or more, preferably 2 to 10, more preferably 3 to 8 epoxy groups in one molecule. .

Examples include glycidyl ethers of polyhydric alcohols and glycidyl esters of polybasic acids. Examples of these include glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether,
And sorbitol hexaglycidyl ether and hexahydrophthalic acid diglycidyl ester.

The number average molecular weight of the resulting polyepoxide is
200-1000, preferably 500-8000, more preferably 800
~ 5000. When the number average molecular weight is less than 200, the curability of the obtained coating film decreases, and when it exceeds 10,000, the solid content of the obtained coating material decreases. Also, the epoxy equivalent is 50-700,
Preferably it is 80-600, more preferably 100-500.
If the epoxy equivalent is larger than the above upper limit, the curability of the resin composition will be insufficient. On the other hand, if it is smaller than the lower limit, the film becomes too hard and the coating film becomes brittle.

The polyepoxide preferably used in the present invention is an epoxy group-containing ethylenically unsaturated monomer of 10 to 60.
%, Preferably 15 to 50% by weight, and 40 to 90% by weight of an ethylenically unsaturated monomer having no epoxy group, preferably
Acrylic polyepoxide obtained by copolymerizing 10 to 60% by weight. If the epoxy group-containing ethylenically unsaturated monomer is less than 10% by weight, the curability is insufficient,
If it is more than 60% by weight, it becomes too hard, resulting in insufficient weather resistance.

Examples of the epoxy group-containing ethylenically unsaturated monomer include glycidyl (meth) acrylate, β
-Methylglycidyl (meth) acrylate and 3,4-epoxycyclohexanyl (meth) acrylate. In order to prepare a resin composition exhibiting well-balanced curability and storage stability, it is preferable to use glycidyl (meth) acrylate.

As the ethylenically unsaturated monomer having no epoxy group, the ethylenically unsaturated monomer having no acid anhydride group (a) (i) for preparing an acrylic polyanhydride (a) (i) can be used. And (2) include the above-mentioned monomers.
Copolymerization can be performed in the same manner as described above.

The obtained acrylic polyepoxide has a number average molecular weight of 500 to 10,000, preferably 1,000 to 8,000, more preferably 1500 to 5,000. When the number average molecular weight is less than 500, the curability of the obtained coating film decreases, and when it exceeds 10,000, the solid content of the obtained coating material decreases. Also, the epoxy equivalent is 50 to 700, preferably 80 to 600, more preferably 100 to 5
00. If the epoxy equivalent is larger than the above upper limit, the curability of the resin composition will be insufficient. On the other hand, if it is smaller than the lower limit, the film becomes too hard and the coating film becomes brittle, which is not preferable.

In order to prepare the ethylenically unsaturated monomers (a), (i) and (2) having no acid anhydride group, the above-mentioned ethylenically unsaturated monomers having a hydroxyl group are also used as the ethylenically unsaturated monomers having no epoxy group. It can be used as a monomer.

In particular, when a hydroxyl group-containing ethylenically unsaturated monomer is used as an ethylenically unsaturated monomer having no epoxy group, the adhesion and recoating properties of the resulting coating film are improved. Further, an acrylic polyepoxide having a hydroxyl group and an epoxy group, which is obtained by using a hydroxyl group-containing ethylenically unsaturated monomer as an ethylenically unsaturated monomer having no epoxy, has a carboxyl group and a carboxylate group as described later. And reacts with and binds to the acrylic polycarboxylic acid (a) having both the hydroxyl group and the epoxy functional group, so that a stronger coating film can be obtained.

The resulting acrylic polyepoxide has a hydroxyl value of 5 to 300 mgKOH / g, preferably 10 to 200 mgKOH / g, more preferably 15 to 150 mgKOH / g. When the hydroxyl value exceeds 300, the solid content of the coating material decreases and the water resistance of the cured coating film is not sufficient. When the hydroxyl value is 5 or less, the adhesion is poor.

Particularly preferred polyepoxides for use in the present invention are those of formula (c) (i) Wherein R is a hydrogen atom or a methyl group, and X is (Wherein, Y is a linear or branched alkylene group having 2 to 8 carbon atoms, m is an integer of 3 to 7, and q is an integer of 0 to 4), or ,formula Wherein R is a hydrogen atom or a methyl group, and n is 2 to 50
Is an integer. ). 5 to 70% by weight of a hydroxyl group-containing ethylenically unsaturated monomer having a structure represented by the following formula:
It is obtained by copolymerizing 60% by weight and optionally (iii) 0 to 85% by weight of an ethylenically unsaturated monomer which does not share both a hydroxyl group and an epoxy group.

In this case, the polyepoxide (c) having a hydroxyl group and an epoxy group preferably has an average of preferably 2 to 12, more preferably 3 to 10, epoxy groups and an average of hydroxyl groups in one molecule. It has 0.5 to 10, more preferably 1 to 8.

The polyepoxide (c) component is used in an amount of 10 to 80% by weight, preferably 20 to 70% by weight, more preferably 30 to 65% by weight, based on the weight of the total solids in the curable resin composition. Can be formulated. When the amount of the polyepoxide is less than 10% by weight, the curability of the obtained coating film is reduced, and when it exceeds 70% by weight, the yellowing resistance is deteriorated.

The curable resin composition of the present invention can be obtained by blending the acrylic polycarboxylic acid (a), polyester polycarboxylic acid (b) and polyepoxide (c) thus obtained.

The blending of the acrylic polycarboxylic acid (a), the polyester polycarboxylic acid (b) and the polyepoxide (c) can be carried out in amounts and methods well known to those skilled in the art. Particularly when using an acrylic polycarboxylic acid having a carboxyl group and a carboxylic ester group as the acrylic polycarboxylic acid (a) and using a polyepoxide having a hydroxyl group and an epoxy group as the polyepoxide (c), it has excellent acid resistance. Thus, a curable resin composition having a high solid content that forms a damaged coating film is obtained.

In this case, the molar ratio of the carboxyl group contained in the acrylic polycarboxylic acid (a) and the polyester polycarboxylic acid (b) to the epoxy group contained in the polyepoxide (c) is 1 / 1.4 to less. 1 / 0.6, preferably 1 / 1.2
A carboxyl group contained in the acrylic polycarboxylic acid (a) or a carboxylic acid ester group bonded to a carbon adjacent to the carboxyl group-bonded carbon, and a polyester polycarboxylic acid (b) and a polyepoxide (c)
It is preferable to carry out the compounding in such an amount that the molar ratio with the hydroxyl group contained in the compound becomes 1 / 2.0 to 1 / 0.5, more preferably 1 / 1.5 to 1 / 0.7.

A resin obtained when the ratio of the carboxyl group contained in the acrylic polycarboxylic acid (a) and the polyester polycarboxylic acid (b) to the epoxy group contained in the polyepoxide (c) exceeds 1 / 0.6. The curability of the composition decreases, and if it is less than 1 / 1.4, the coating film turns yellow. The carboxyl group contained in the acrylic polycarboxylic acid (a) or the carboxylic acid ester group bonded to the carbon adjacent to the carboxyl group-bonded carbon and the hydroxyl group contained in the polyester polycarboxylic acid (b) and the polyepoxide (c) If the molar ratio is more than 1 / 0.5, the curability of the obtained resin composition will be reduced, and if it is less than 1 / 2.0, the hydroxyl group will be excessive and the water resistance will be reduced. This amount can be calculated from the hydroxyl value, acid value and epoxy equivalent of each polymer by a calculation method well known to those skilled in the art.

The curing mechanism of the curable resin composition of the present invention thus obtained is as follows. First, the carboxyl group in the polyacrylic polycarboxylic acid (a) reacts with the carboxylic acid ester group by heating to form an acrylic resin. Polycarboxylic acid (a)
An acid anhydride group is formed therein, and a free monoalcohol is formed. The generated monoalcohol is removed from the system by evaporation. The acid anhydride group formed in the polyacrylic polycarboxylic acid (a) is a polyester polycarboxylic acid
By reacting with (b) and the hydroxyl group contained in the polyepoxide (c), a crosslinking point is formed and a carboxyl group is formed again. The carboxyl group and the carboxyl group present in the polyester polycarboxylic acid (b) react with the epoxy group present in the polyepoxide (c) to form a crosslinking point. As described above, the three kinds of polymers react with each other, whereby the curing proceeds, and a high crosslinking density can be provided.

In addition to the above-mentioned essential components, the curable resin composition of the present invention may optionally contain a binder component such as a silicone polymer. This is because it is effective for increasing the solid content concentration of the obtained resin composition.

The silicone polymer which can be suitably used in the present invention is, for example, a compound represented by the formula [Wherein, R ^{1 to} R ⁶ independently represent an alkyl group having 1 to 10 carbon atoms or a carbon number, provided that at least one of them has an alkoxy group and at least one other has an epoxy group. 1 to 10 phenyl groups, 1 to 10 carbon atoms phenethyl group,
An alkoxy group having 1 to 5 carbon atoms and a compound represented by the formula R ⁷ —Si (O
R ⁸ ) ₃ , R ⁷ -Si (OR ⁸ ) ₂ CH ₃ , R ⁷ -Si (OR ⁸ ) (CH
₃ ) ₂ , and R ⁷ -Y (wherein, R ⁷ is a linear or branched alkylene group or a linear or branched alkylene group having an ether bond or an ester bond, and R ⁸ has 1 to 1 carbon atoms. 5 is an alkyl group, and Y is a linear or cyclic alkyl group having an epoxy group.), L is an integer of 1 to 20, Is an integer from 0 to 4 and n is an integer from 0 to 2. And a silicone polymer having an epoxy group and / or an alkoxy group. However, the repeating units constituting the silicone polymer may be arranged at random, and are not limited to the order of the above formula.

Examples of the silicone polymer having an epoxy group include “NUC Silicone” series manufactured by Nippon Unicar Co., Ltd. Examples of the silicone polymer containing an alkoxy group include, for example, `` KC89-
S "and the like. Examples of the silicone polymer having an epoxy group and an alkoxy group include “MKC silicate MSEP2” series manufactured by Mitsubishi Chemical Corporation and “NUC Silicone” series manufactured by Nippon Unicar.

The method for producing such a silicone polymer is described in the 1990 Organism of Silicon Silicon Materials Symposium, Vol.
Page 30 to page 30. The epoxy group may be present in the middle or at the end of a chain or cyclic hydrocarbon chain. In the silicone polymer (II), the chain or cyclic hydrocarbon having an epoxy group represented by Y is represented by, for example, the following formula.

[0075]

Embedded image

Wherein R ¹¹ , R ¹² and R ¹³ are hydrocarbons having up to 4 carbon atoms. ]

In the present specification, the epoxy equivalent is defined as
The alkoxy equivalent represents the number of grams of a compound containing 1 g equivalent of an alkoxy group, and the hydroxy equivalent represents the g of a compound containing 1 g equivalent of a hydroxyl group.
Represents a number.

The epoxy equivalent of this silicone polymer is
At 100-1500, the alkoxy equivalent is 50-1500. If the epoxy equivalent is less than 100, the storage stability of the paint is poor,
If it exceeds 0, the curability will be poor. The preferred range of the epoxy equivalent is from 140 to 1000, more preferably from 180 to 700. A preferred range of the alkoxy equivalent is from 60 to 800,
More preferably, it is 80 to 500.

The silicone polymer component having such an epoxy group and an alkoxy group contains up to 30% by weight, preferably 1 to 20% by weight, more preferably 1% by weight, based on the weight of the total solids in the curable resin composition. It may be present in an amount of 3 to 15% by weight. When the amount of the silicone polymer component exceeds 30% by weight, the storage stability of the obtained paint decreases.

In the present invention, the epoxy group and / or
Alternatively, a silicone polymer containing a hydroxyl group and a carboxyl group may be used together with or instead of a silicone polymer having an alkoxy group. The silicone polymer having a hydroxyl group and a carboxyl group,
It is obtained by half-esterifying a silicone polymer having a hydroxyl group with an acid anhydride group-containing compound.

The number average molecular weight of this silicone polymer is
It is 500-6000, preferably 1000-4500, the hydroxyl value is 2-120, preferably 10-80, and the acid value is 20-180, preferably 35-150. If the number average molecular weight, hydroxyl value or acid value exceeds the upper limit of the above range, it becomes difficult to prepare a paint having a sufficiently high solid content, and if it falls below the lower limit, the curability of the obtained paint will decrease.

The hydroxyl-containing silicone polymer is commercially available, for example, of the formula

[0083]

Embedded image

KR-2001 manufactured by Shin-Etsu Chemical Co., Ltd., NUC-Silicone series manufactured by Nippon Unicar, and the like.

The silicone polymer having a hydroxyl group includes 1
It is preferable to have an average of 3 to 12 hydroxyl groups in the molecule. If the average number of hydroxyl groups is less than 3, curability will be insufficient,
If it exceeds 12, the viscosity becomes high, and it becomes difficult to increase the solid content in the resin composition.

The above acid anhydride group-containing compound is used at room temperature to 120 ° C.
It provides carboxy functionality by reacting with hydroxyl groups under normal reaction conditions such as ° C, normal pressure. Carbon number 8
The use of an acid anhydride group-containing compound having a saturated or unsaturated cyclic group of from 12 to 12 is preferable because the compatibility of the resin becomes good.

Examples of the acid anhydride group-containing compound include hexahydrophthalic anhydride, phthalic anhydride, 4-methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride and the like.

The half esterification reaction between the hydroxyl group-containing silicone polymer and the acid anhydride group-containing compound is carried out according to a usual method, for example, at a temperature of room temperature to 120 ° C. for 30 minutes to 8 hours. If the reaction is carried out for a long time at a temperature exceeding 120 ° C., a high-molecular-weight silicone polyester is formed due to a polyesterification reaction. Such a silicone polyester is not preferable for use in the present invention because it has a small number of functional groups and a high viscosity.

The amount of the silicone polymer component containing a hydroxyl group and a carboxyl group is up to 30% by weight, preferably 1 to 20% by weight, more preferably 1 to 20% by weight, based on the total solids in the curable resin composition. It may be present in an amount of 3 to 15% by weight. When the amount of the silicone polymer component exceeds 30% by weight, the storage stability of the obtained paint decreases.

When a silicone polymer component having an epoxy group and an alkoxy group and a silicone polymer component having a hydroxyl group and a carboxyl group are used in combination, the total amount thereof is based on the weight of the total solids in the curable resin composition. Up to 30% by weight, preferably 1 to 20% by weight, more preferably 3 to 15% by weight, can be incorporated. When the amount of the silicone polymer component exceeds 30% by weight, the storage stability of the obtained paint decreases.

In addition to the above components, the curable resin composition of the present invention may contain a curing catalyst usually used for an esterification reaction between an acid and an epoxy such as a quaternary ammonium salt. Specific examples of other catalysts that can be used in the curable resin composition of the present invention include benzyltriethylammonium chloride or bromide, tetrabutylammonium chloride or bromide, salicylate or glycolate, and paratoluenesulfonate. These curing catalysts may be used as a mixture.

The curing catalyst can be used in an amount of generally 0.01 to 3.0% by weight, preferably 0.1 to 1.5% by weight, more preferably 0.4 to 1.2% by weight, based on the solid content of the resin composition. If the amount of the catalyst used is less than 0.01% by weight, the curability decreases,
If the amount is more than the weight%, the storage stability is reduced.

Further, Japanese Patent Application Laid-Open Nos.
As described in JP-A-279713, a tin-based compound may be used in combination with these. Examples of the tin-based catalyst include dimethyltin bis (methylmalate), dimethyltinbis (ethylmalate), dimethyltinbis (butylmalate), and dibutyltinbis (butylmalate).

The tin compound is generally used in an amount of 0.05 to 6% by weight, preferably 0.1 to 4.0% by weight, based on the solid content of the resin composition.
More preferably, it can be used in an amount of 0.2 to 2.0% by weight. When the amount of the tin-based compound used is less than 0.05% by weight, the storage stability decreases, and when it exceeds 6% by weight, the weather resistance decreases.
When a curing catalyst and a tin compound are used in combination, the weight ratio of the curing catalyst to the tin compound is preferably 1/4 to 1 / 0.2.

In order to increase the crosslink density and improve the water resistance, a blocked isocyanate may be added to the resin composition of the present invention. Also, to improve the weather resistance of the coating film,
UV absorbers, hindered amine light stabilizers, antioxidants and the like may be added. Further, crosslinked resin particles as a rheology control agent or a surface conditioner for adjusting the appearance may be added. Furthermore, solvents such as alcohol solvents (eg, methanol, ethanol, propanol, and butanol), hydrocarbon solvents, and ester solvents may be used as diluents for viscosity adjustment and the like.

When crosslinked resin particles are used, the curable resin composition of the present invention has a resin content of 0.01 to 1 to 100 parts by weight based on 100 parts by weight of the resin.
It is added in an amount of 0 parts by weight, preferably 0.1 to 5 parts by weight.
When the amount of the crosslinked resin particles exceeds 10 parts by weight, the appearance deteriorates, and when the amount is less than 0.01 parts by weight, the rheology control effect cannot be obtained.

The resin used in the present invention has an acid group as a functional group. Accordingly, an aqueous resin composition using water as a medium can be obtained by neutralizing with an amine.

The present invention also provides a coating composition containing the above-mentioned curable resin composition as a binder component. The method for producing the coating composition of the present invention is not particularly limited, and all methods known to those skilled in the art can be used.

The coating composition of the present invention can be applied by spray coating, brush coating, dip coating, roll coating, flow coating, or the like. The substrate may be primed or semi-coated, if desired. Known undercoating and intermediate coatings can be used.

The coating composition of the present invention can be advantageously used on any substrate, such as wood, metal, glass, cloth, plastic, foam and the like, especially on plastic and metal surfaces, such as steel, aluminum and alloys thereof. Generally, the thickness will vary depending on the desired application. Often 0.
5 to 3 mils are useful.

After coating on the substrate, the coating film is cured. Curing is performed at 100 to 180 ° C, preferably 120 to 160 ° C, to obtain a cured coating film having a high degree of crosslinking. Although the curing time varies depending on the curing temperature and the like, curing at 120 ° C. to 160 ° C. for 10 to 30 minutes is appropriate.

In one preferred embodiment of the present invention, a coating is provided by a method comprising the following steps. A step of applying a water-based or solvent-based base paint on an undercoated or intermediate-coated substrate; without curing the base coating film,
A method for forming a coating film, comprising: a step of applying the clear coating composition according to claim 9; and a step of curing the base coating film and the clear coating film by heating.

[0103]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Unless otherwise specified, the amounts are based on weight.

Synthesis Example 1 Synthesis of acrylic polycarboxylic acid (a) -1 700 parts by weight of xylene, Solvesso 100 in a 3 L reaction tank equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen inlet pipe, and a suitable funnel.
500 parts by weight of an aromatic hydrocarbon solvent (manufactured by Esso) were charged, and the temperature was raised to 130 ° C. In the above container, using a suitable funnel, styrene monomer 300 parts by weight, 2-ethylhexyl acrylate 350 parts by weight, isobutyl methacrylate 150 parts by weight, acrylic acid 200 parts by weight, and t-butyl peroxy 2-
A solution consisting of 150 parts by weight of ethylhexanoate and 300 parts by weight of xylene was dropped over 3 hours. After maintaining at 130 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 20 parts by weight of t-butylperoxy 2-ethylhexanoate and 20 parts by weight of xylene was added dropwise over 30 minutes. After the end of this dropping, 1 more
After the reaction was continued at 130 ° C. for 1 hour, 1100 parts by weight of the solvent was removed, and the number average molecular weight was 1800, and the acid value was 156 mg KOH / g (solid content). 70% varnish was obtained.

Synthesis Example 2 Synthesis of Acrylic Polycarboxylic Acid (a) -2 Except for using the compositions shown in Table 1 below, the same procedures as in Synthesis Example 1 were carried out except that the number average molecular weight was 1900 and the acid value was 140 mg KOH / g. A varnish containing acrylic polycarboxylic acid (a) -2 and having a nonvolatile content of 70% was obtained.

[0106]

[Table 1]

Synthesis Example 3 Synthesis of Acrylic Polycarboxylic Acid (a) -3 Except for using the composition shown in Table 2 below, the same procedure as in Synthesis Example 1 was carried out except that the number average molecular weight was 1800 and the acid value was 150 mgKOH / g. A varnish containing acrylic polycarboxylic acid (a) -3 and having a nonvolatile content of 70% was obtained.

[0108]

[Table 2]

Synthesis Example 4 Synthesis of Acrylic Polycarboxylic Acid (a) -4 Having Carboxyl Group and Carboxylic Acid Ester Group A 3 L reactor equipped with a thermometer, stirrer, cooling tube, nitrogen inlet tube, and funnel. Xylene 700 parts, Solvesso 100 350
Then, the temperature was increased to 130 ° C. In the above container, using a funnel, 300 parts of styrene, 109 parts of 2-ethylhexyl methacrylate, 325 parts of isobutyl acrylate, acrylic acid
A solution consisting of 26 parts, 240 parts of maleic anhydride, 300 parts of propylene glycol monomethyl ether acetate, 150 parts of t-butylperoxy 2-ethylhexanoate and 150 parts of xylene was dropped over 3 hours. After maintaining at 130 ° C. for 30 minutes after the completion of the dropwise addition, a solution composed of 20 parts of t-butylperoxy 2-ethylhexanoate and 20 parts of xylene was added dropwise over 30 minutes. After this dripping is completed, for another 1 hour
After the reaction was continued at 130 ° C., 1100 parts of the solvent was removed to obtain a varnish of 70% nonvolatile containing acrylic polyanhydrides (a) and (i) having a number average molecular weight of 2,000.

To 1590 parts of the obtained varnish, methanol 125 was added.
The resulting mixture was reacted at 70 ° C. for 23 hours to obtain a varnish containing an acrylic polycarboxylic acid (a) -4 having an acid value of 158 mgKOH / g.
Incidentally, the infrared absorption spectrum of this acrylic polycarboxylic acid (a) -4 was measured, and the absorption of an acid anhydride group (1785 cm
^-1 ) disappeared.

Synthesis Example 5 Synthesis of Acrylic Polycarboxylic Acid (a) -5 Having Carboxyl Group and Carboxylic Acid Ester Group A number average was obtained in the same manner as in Synthesis Example 4 except that the composition shown in Table 3 below was used. A varnish having a nonvolatile content of 65% and containing an acrylic polycarboxylic acid (a) -5 having a molecular weight of 2,000 and an acid value of 165 mgKOH / g was obtained.

[0112]

[Table 3]

Synthesis Example 6 Synthesis of acrylic polycarboxylic acid (a) -6 having a carboxyl group and a carboxylic acid ester group The same procedure as in Synthesis Example 4 was carried out, except that the composition shown in Table 4 below was used. A varnish having a nonvolatile content of 65% and containing an acrylic polycarboxylic acid (a) -6 having a molecular weight of 2100 and an acid value of 157 mgKOH / g was obtained.

[0114]

[Table 4]

Synthesis Example 7 Synthesis of Polyester Polycarboxylic Acid (b) -1 In a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
278 parts of ethyl 3-ethoxypropionate, 268 parts of trimethylolpropane, 228 parts of ε-caprolactone, and 0.1 part of dibutyltin oxide were charged and heated to 150 ° C.

After maintaining at 150 ° C. for 2 hours, 616 parts of hexahydrophthalic anhydride dissolved by heating was added,
Maintained at 150 ° C. for 1 hour, a polyester polycarboxylic acid having a number average molecular weight of 800, a weight average molecular weight / number average molecular weight of 1.18, an acid value of 202 mg KOH / g (solid content) and a hydroxyl value of 101 mg KOH / g (solid content) ( b) A varnish having a nonvolatile content of 80% containing -1 was obtained.

Synthesis Example 8 Synthesis of Polyester Polycarboxylic Acid (b) -2 In a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
271 parts of ethyl 3-ethoxypropionate, 268 parts of trimethylolpropane, 200 parts of δ-valerolactone, and 0.1 part of dibutyltin oxide were charged and heated to 150 ° C.

After maintaining at 150 ° C. for 2 hours, 616 parts of hexahydrophthalic anhydride dissolved by heating was added,
Hold at 150 ° C. for 1 hour, number average molecular weight 800, weight average molecular weight / number average molecular weight = 1.17, acid value 207 mgKOH / g (solid content),
A varnish having a nonvolatile content of 80% and containing a polyester polycarboxylic acid (b) -2 having a hydroxyl value of 103 mgKOH / g (solid content) was obtained.

Synthesis Example 9 Synthesis of Polyester Polycarboxylic Acid (b) -3 In a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
234 parts of ethyl 3-ethoxypropionate, 134 parts of trimethylolpropane, 342 parts of ε-caprolactone, and 0.1 part of dibutyltin oxide were charged and heated to 150 ° C.

After maintaining at 150 ° C. for 2 hours, 462 parts of hexahydrophthalic anhydride dissolved by heating are added,
Hold at 150 ° C. for 1 hour, number average molecular weight 1200, weight average molecular weight / number average molecular weight = 1.22, acid value 179 mgKOH / g (solid content)
Non-volatile content of the polyester polycarboxylic acid (b) -3 of 80
% Varnish was obtained.

Synthesis Example 10 Synthesis of Polyester Polycarboxylic Acid (b) -4 In a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
275 parts of ethyl 3-ethoxypropionate, 136 parts of pentaerythritol, 228 parts of ε-caprolactone, and 0.1 part of dibutyltin oxide were charged and heated to 180 ° C.

After maintaining at 180 ° C. for 2 hours, 462 parts of hexahydrophthalic anhydride dissolved by heating are added,
Maintained at 150 ° C. for 1 hour, a polyester polycarboxylic acid having a number average molecular weight of 1100, a weight average molecular weight / number average molecular weight of 1.20, an acid value of 204 mg KOH / g (solid content), and a hydroxyl value of 68 mg KOH / g (solid content) ( b) A varnish having a nonvolatile content of 75% containing -4 was obtained.

Synthesis Example 11 Synthesis of Polyester Polycarboxylic Acid (b) -5 136 parts of pentaerythritol, ε-caprolactone 91 were placed in a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
Two parts and 0.2 part of dibutyltin oxide were charged and heated to 180 ° C.

After maintaining at 180 ° C. for 2 hours, 397 parts of ethyl 3-ethoxypropionate were added, 538 parts of hexahydrophthalic anhydride dissolved by heating were added, and the mixture was maintained at 150 ° C. for 1 hour. Number-average molecular weight 2500, weight-average molecular weight / number-average molecular weight = 1.35, acid value 124 mgKOH / g (solid content), hydroxyl value 25 mgKOH / g (solid content) 80% non-volatile content including polyester polycarboxylic acid (b) -5 Varnish was obtained.

Synthesis Example 12 Synthesis of Polyester Polycarboxylic Acid (b) -6 In a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
275 parts of ethyl 3-ethoxypropionate, 136 parts of pentaerythritol, 456 parts of ε-caprolactone, and 0.1 part of dibutyltin oxide were charged and heated to 180 ° C.

After maintaining at 180 ° C. for 2 hours, 576 parts of trimellitic anhydride were added, and the temperature was maintained at 150 ° C. for 1 hour, and the number average molecular weight was 1800, weight average molecular weight / number average molecular weight =
A varnish having a nonvolatile content of 75% and containing a polyester polycarboxylic acid (b) -6 having an acid value of 1.25, an acid value of 192 mgKOH / g (solid content), and a hydroxyl value of 48 mgKOH / g (solid content) was obtained.

Synthesis Example 13 Synthesis of Polyester Polycarboxylic Acid (b) -7 136 parts of pentaerythritol and ε-caprolactone 91 were placed in a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, and a nitrogen introduction pipe.
Two parts and 0.2 part of dibutyltin oxide were charged and heated to 180 ° C.

After maintaining at 180 ° C. for 2 hours, 215 parts of ethyl 3-ethoxypropionate were added, 154 parts of hexahydrophthalic anhydride dissolved by heating were added, and the mixture was maintained at 150 ° C. for 1 hour. Number-average molecular weight 2200, weight-average molecular weight / number-average molecular weight = 1.32, acid value 47 mgKOH / g (solid content), hydroxyl value 140 mgKOH / g (solid content), 80% non-volatile content including polyester polycarboxylic acid (b) -7 Varnish was obtained.

Synthesis Example 14 Synthesis of Polyester Polycarboxylic Acid (b) -8 210 parts of isophthalic acid and 3 parts of azelaic acid were placed in a reaction vessel equipped with a thermometer, stirrer, cooling pipe, nitrogen inlet pipe, water separator, and rectification tower.
70 parts, trimethylolpropane 400 parts, neopentyl glycol 100 parts, and Kajura E (manufactured by Shell Chemical Co., Ltd.) 50 parts were charged and heated. When the raw materials are melted and stirring becomes possible, 0.2 parts of dibutyltin oxide is charged and stirring is started, and the temperature of the reaction vessel is reduced to 2 parts.
The temperature was raised to 20 ° C. However, from 180 ° C to 220 ° C,
The temperature was raised at a constant rate over 3 hours. The condensed water generated was distilled out of the system. When the temperature reached 220 ° C., the temperature was maintained. After 1 hour, 30 parts of xylene was gradually added as a reflux solvent into the reaction vessel, and the reaction was switched to condensation in the presence of a solvent to continue the reaction. When the resin acid value reached 10.0, the mixture was cooled to 150 ° C., and 420 parts of phthalic anhydride was added.
Cooled to 00 ° C. Further, 275 parts of ethyl 3-ethoxypropionate and 275 parts of butyl acetate were added, and the number average molecular weight was 4200,
A varnish of 70% nonvolatile containing polyester polycarboxylic acid (b) -8 having a weight average molecular weight / number average molecular weight of 3.3 and an acid value of 115 mgKOH / g (solid content) was obtained.

Synthesis Example 15 Synthesis of Polyepoxide (c) -1 250 parts of xylene and 200 parts of propylene glycol monomethyl ether acetate were charged into a 2 L reaction tank equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a suitable funnel. , 130 ℃
The temperature rose.

Using a dropping funnel, 450 parts of glycidyl methacrylate, isobornyl methacrylate 2
A solution consisting of 36 parts, 64 parts of 4-hydroxybutyl acrylate, 250 parts of t-butylstyrene, 110 parts of t-butylperoxy 2-ethylhexanoate and 150 parts of xylene was added dropwise over 3 hours.

After maintaining the temperature at 130 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy-2-ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes.

After the completion of the dropwise addition, the reaction was continued at 130 ° C. for an additional hour, and 270 parts of the solvent was removed.
A varnish having a nonvolatile content of 72% and containing an acrylic polyepoxide (c) -1 having an epoxy equivalent of 200, an epoxy equivalent of 316, and a hydroxyl value of 25 mgKOH / g (solid content) was obtained.

Synthesis Example 16 Synthesis of Polyepoxide (c) -2 250 parts of xylene and 200 parts of propylene glycol monomethyl ether acetate were charged into a 2 L reaction tank equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a suitable funnel. , 135 ° C
The temperature rose.

Using a dropping funnel, 500 parts of glycidyl methacrylate and 250 parts of isobutyl methacrylate
, 250 parts of t-butylstyrene, and 120 parts of t-butylperoxy-2-ethylhexanoate and 140 parts of xylene were added dropwise over 3 hours.

After maintaining at 135 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy-2-ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes.

After completion of the dropwise addition, the reaction was continued at 135 ° C. for an additional hour, and 270 parts of the solvent was removed.
Acrylic polyepoxide (c) with 800, epoxy equivalent 284
A varnish with a nonvolatile content of 72% containing 2 was obtained.

Synthesis Example 17 Synthesis of Polyepoxide (c) -3 250 parts of xylene and 200 parts of propylene glycol monomethyl ether acetate were charged into a 2 L reaction tank equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a suitable funnel. , 130 ℃
The temperature rose.

Using a dropping funnel in the above reaction vessel, 550 parts of 3,4-epoxycyclohexylmethyl methacrylate, 130 parts of isobornyl acrylate, 70 parts of 2-hydroxyethyl methacrylate, 250 parts of t-butylstyrene, 110 parts of t-butyl peroxy 2-ethylhexanoate and xylene 1
A solution consisting of 50 parts was added dropwise over 3 hours.

After maintaining the temperature at 130 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy-2-ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes.

After the completion of the dropwise addition, the reaction was continued at 130 ° C. for an additional hour, and 270 parts of the solvent was removed.
A varnish having a nonvolatile content of 72% and containing an acrylic polyepoxide (c) -3 having an epoxy equivalent of 200, an epoxy equivalent of 357, and a hydroxyl value of 30 mgKOH / g (solid content) was obtained.

Synthesis Example 18 Synthesis of Polyepoxide (c) -4 700 parts of xylene and 525 parts of propylene glycol monomethyl ether acetate were charged into a 3 L reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a lower funnel. , 130 ℃
The temperature rose.

Using a dropping funnel, 200 parts of Vover 9300 parts, 300 parts of glycidyl methacrylate, 230 parts of 4-hydroxybutyl acrylate, 340 parts of cyclohexyl methacrylate, and 340 parts of t-butylperoxy 2-ethylhex A solution consisting of 120 parts of noate and 200 parts of xylene was added to 3
It was dropped over time.

After maintaining the temperature at 130 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy-2-ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes.

After the completion of the dropwise addition, the reaction was continued at 130 ° C. for an additional hour, and the solvent was removed in an amount of 1200 parts to give a number average molecular weight of 18
A varnish having a nonvolatile content of 77% and containing an acrylic polyepoxide (c) -4 having an epoxy equivalent of 473 and a hydroxyl value of 90 mgKOH / g (solid content) was obtained.

Synthesis Example 19 Synthesis of Polyepoxide (c) -5 250 parts of xylene and 300 parts of propylene glycol monomethyl ether acetate were charged into a 2 L reaction tank equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a suitable funnel. , 135 ° C
The temperature rose.

Using a dropping funnel, 355 parts of glycidyl methacrylate and 90 parts of isobutyl methacrylate
Parts, t-butylstyrene 250 parts, 4-hydroxybutyl acrylate 238 parts, 2-hydroxyethyl methacrylate 67 parts, t
A solution consisting of 140 parts of 2-butylperoxy-2-ethylhexanoate and 100 parts of xylene was added dropwise over 3 hours.

After maintaining at 135 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy-2-ethylhexanoate and 30 parts of xylene was added dropwise over 30 minutes.

After the completion of the dropwise addition, the reaction was further continued at 135 ° C. for 1 hour, 320 parts of the solvent was removed, and the number average molecular weight was 1800.
A varnish having a nonvolatile content of 72% and containing an acrylic polyepoxide (c) -5 having an epoxy equivalent of 400 and a hydroxyl value of 122 mgKOH / g was obtained. Synthesis Example 20 Synthesis of acrylic polycarboxylic acid (a) -7 having a carboxyl group and a carboxylic acid ester group Xylene 330 was placed in a 3 L reaction tank equipped with a thermometer, a stirrer, a cooling tube, a nitrogen inlet tube, and a funnel. Parts and 100 parts of propylene glycol monomethyl ether acetate, 130
The temperature was raised to ° C. In the above container, using a suitable funnel, 300 parts of styrene, 120 parts of 2-ethylhexyl methacrylate, 369 parts of 2-ethylhexyl acrylate, 26 parts of acrylic acid, 185 parts of maleic anhydride, 300 parts of propylene glycol monomethyl ether acetate, And a solution consisting of 100 parts of t-butylperoxy 2-ethylhexanoate and 100 parts of xylene was dropped over 3 hours. 13 for 30 minutes after dropping
After maintaining at 0 ° C., a solution consisting of 10 parts of t-butylperoxy 2-ethylhexanoate and 60 parts of xylene was added dropwise over 30 minutes. After completion of the dropping, the reaction was further continued at 130 ° C. for 1 hour to obtain a varnish having a number-average molecular weight of 3000 and containing 52% of a nonvolatile matter containing acrylic polyanhydride (a) (i).

To 2000 parts of the obtained varnish, 90 parts of methanol was added and reacted at 70 ° C. for 23 hours to obtain a varnish containing an acrylic polycarboxylic acid (a) -7 having an acid value of 126 mgKOH / g. still,
The infrared absorption spectrum of this acrylic polycarboxylic acid (a) -7 was measured, and it was confirmed that the absorption (1785 cm ^-1 ) of the acid anhydride group disappeared. Synthesis Example 21 Synthesis of polyepoxide (c) -7 In a 3 L reaction tank equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a funnel, 520 parts of xylene and 50 parts of propylene glycol monomethyl ether acetate were charged at 126 ° C.
The temperature rose.

Using a dropping funnel, 250 parts of styrene, 379 parts of glycidyl methacrylate, 243 parts of isobornyl methacrylate, 4-hydroxybutyl acrylate
A solution consisting of 28 parts and 110 parts of t-butylperoxy-2-ethylhexanoate and 110 parts of xylene was added dropwise over 3 hours.

After maintaining at 126 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy-2-ethylhexanoate and 20 parts of xylene was added dropwise over 30 minutes.

After the completion of the dropwise addition, the reaction was continued at 126 ° C. for another hour, and the number average molecular weight was 3000 and the epoxy equivalent was 37.
5. A varnish having a nonvolatile content of 58% containing an acrylic polyepoxide (c) -7 having a hydroxyl value of 90 mgKOH / g (solid content) was obtained.

Example 1 Preparation of Crosslinked Resin Particles In a reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen inlet tube, a cooling tube and a decanter, 213 parts of bishydroxyethyltaurine, 208 parts of neopentyl glycol, phthalic anhydride
296 parts, 376 parts of azelaic acid and 30 parts of xylene were charged and heated. Water generated by the reaction was removed by azeotropic distillation with xylene. The reaction solution temperature was raised to 210 over about 3 hours from the start of reflux.
C. and stirring and dehydration were continued until the acid value corresponding to carboxylic acid reached 135. After cooling the liquid temperature to 140 ° C., 500 parts of “Cajura E10” (glycidyl versatate ester manufactured by Shell Co.) was added dropwise over 30 minutes, and then stirring was continued for 2 hours to complete the reaction. An amphoteric group-containing polyester resin having an acid value of 55, a hydroxyl value of 91 and a number average molecular weight of 1250 was obtained.

The zwitterionic group-containing polyester resin 10
Parts, 140 parts of deionized water, dimethylethanolamine 1
Parts, 50 parts of styrene and 50 parts of ethylene glycol dimethacrylate were vigorously stirred in a stainless steel beaker to prepare a monomer suspension. Also, an aqueous initiator solution was prepared by mixing 0.5 parts of azobiscyanovaleric acid, 40 parts of deionized water, and 0.32 part of dimethylethanolamine.

A reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen inlet tube and a cooling tube was charged with 5 parts of the amphoteric group-containing polyester resin, 280 parts of deionized water and 0.5 part of dimethylethanolamine. Warmed. Here, the monomer suspension and 40.82 parts of the initiator aqueous solution were simultaneously added dropwise over 60 minutes, and the reaction was continued for further 60 minutes, and then the reaction was terminated. A crosslinked resin particle emulsion having a particle size of 55 nm as measured by dynamic light scattering was obtained.

Xylene was added to this emulsion, water was removed by azeotropic distillation under reduced pressure, and the medium was replaced with xylene to obtain a xylene solution of crosslinked resin particles having a solid content of 20% by weight.

Preparation of Clear Coating Composition The acrylic polycarboxylic acid (a) -1 obtained in Synthetic Example 1 and the polyester polycarboxylic acid (b) -1 obtained in Synthetic Example 7 were prepared according to the formulation shown in Table 3. Polyepoxide (c) -1, obtained in Example 15, 0.5 part of tetrabutylammonium bromide curing catalyst, 0.5 part of dibutyltin bis (butyl maleate) curing catalyst, 2 parts of Ciba-Geigy ultraviolet absorber "Tinuvin 900", 3 parts of Sankyo 1 part of a photo-regulating agent "Sanol LS-440" and 0.1 part of a surface preparation "Modaflow" manufactured by Monsanto Co., Ltd. were blended while stirring with a disper to prepare a curable resin composition. To the obtained resin composition, 10 parts of a xylene solution of the crosslinked resin particles prepared as described above was added, and then butyl acetate / xylene = 1 /
The viscosity was adjusted to 30 seconds with Ford Cup No. 4 using the solvent consisting of No. 1 to obtain a clear coating composition.

After adjusting the paint non-volatile matter (NV) paint viscosity to 30 seconds at 20 ° C. using Ford Cup No. 4, 0.5 g of the paint composition was precisely weighed and diluted with 3 cc of toluene, and then at 110 ° C. for 1 hour. The non-volatile content (% by weight) of the baked paint was measured.

On the other hand, cationic electrodeposition paint (Powertop U-5 manufactured by Nippon Paint Co., Ltd.) was applied to a phosphoric acid-treated steel sheet having a thickness of 0.8 mm.
0) and intermediate coating (Nippon Paint Co., Ltd. Olga P-2)
On a process test plate that was coated to a dry thickness of 25 μm and 40 μm, respectively, air-painted a solvent type high solid base paint (manufactured by Nippon Paint Co., Ltd.) so that the thickness of the dry coating film was about 16 μm, By setting for about 7 minutes, a base coating film was formed.

Further, the obtained clear coating composition was
Using an electrostatic coating machine (“Auto Rea” manufactured by Landsberg Gemma Co.), apply with an atomizing pressure of 5 kg / cm ^{2 so} that the dry film thickness becomes about 40 μm. After setting for about 7 minutes, Bake for a minute.

The solvent-type high solid base paint was mixed with an acrylic resin manufactured by Nippon Paint Co. (non-volatile content: 80%).
%, Hydroxyl value 100, acid value 30, and number average molecular weight 1800) 20
Part, polyester made by Nippon Paint Co., Ltd.
30 parts of hydroxyl value 100, acid value 12 and number average molecular weight 2600), 40 parts of melamine resin `` Cymel 202 '' (80% non-volatile content) manufactured by Mitsui Cytec, melamine resin `` Cymel 327 '' (non-volatile content) manufactured by Mitsui Cytec 90%), 10 parts of "Alpaste Al60-600" (65% non-volatile content) manufactured by Toyo Aluminum Co., Ltd., and 7 parts of isopropyl alcohol.

The performance of the obtained coating film was evaluated as follows. Table 6 shows the results.

The pencil hardness was measured in accordance with JIS K5400 8, 4.2.

[0165] The water resistance obtained cured coating film was immersed for 10 days at 40 ° C. in tap water, and the coating film surface was visually evaluated on the following criteria. No change observed ○ Slight traces observed △ Abnormality of coating film ×

A 2 × 2 cm flannel fabric coated with 1 g of a 50% aqueous dispersion of an abrasion-resistant cleanser (“New Homing Cleanser” manufactured by Kao Corporation (87% abrasive, 5% surfactant, etc.)) was applied. It was mounted on the sliding head of a vibration dyeing friction fastness tester (manufactured by Daiei Kagaku Seiki Co., Ltd.). After the sliding head with a load of 500 g was reciprocated 20 times on the obtained cured coating film, the test portion was measured for 20 ° gloss, and the gloss retention (%) was calculated.

Acid resistance The obtained cured coating film was added to 0.5 ml of a 1% by weight aqueous sulfuric acid solution.
After contacting at 5 ° C. for 30 minutes, the coating film surface was visually evaluated according to the following criteria. When no abnormality is observed 5 When a trace is slightly observed 4 When a trace is clearly recognized 3 When a group of fine holes is recognized 2 When a group of fine holes is recognized on the entire surface 1

[0168] weather resistance Iwasaki Electric Co., Ltd. in the "Eye Super UV tester SUV-W13", a black panel temperature of 63 ℃, under the conditions of 70% humidity 100mW /
24 hours of UV irradiation of cm ² and black panel temperature of 50
After 5 cycles of 24 hours left as one cycle under conditions of 100 ° C. and 100% humidity, the coating film surface was visually evaluated according to the following criteria. When no abnormality is observed ○ When slight cracking is observed △ When severe cracking is observed ×

A high solid base paint (manufactured by Nippon Paint Co., Ltd.) is applied by air spray coating to the adhesive (non-sand recoatable) intermediate paint coated plate so that the thickness of the dried paint film becomes about 16 μm, and the setting is carried out for about 7 minutes. did. However,
When an aqueous base paint (manufactured by Nippon Paint Co., Ltd.) was used (Examples 16 and 17), it was air-sprayed, set for about 1 minute, and then preheated at 80 ° C. for 5 minutes.

Next, the composition (solid content) shown in Tables 6 and 7
Each resin component is blended, the viscosity is adjusted in 30 seconds with Ford Cup No. 4, and the obtained clear coating composition is atomized with an electrostatic coating machine `` Auto Rea '' (manufactured by Ransberg Gemma). 5kg / cm
^The coating was performed so as to have a dry film thickness of about 40 μm in 2 and set for about 7 minutes, followed by baking at 160 ° C. for 30 minutes.

The obtained coated plate was allowed to stand in a desiccator for 30 minutes, after which the high solid base paint (manufactured by Nippon Paint Co., Ltd.) was painted and set again in the same manner as described above, and the clear paint was applied on the paint film. The coating composition was painted and set as described above and baked at 120 ° C. for 30 minutes.

[0172] A cutter knife was applied to the surface of the formed coating film.
Using (NT cutter S type or A type), make a cross cut of 11 length × 11 width at 2mm interval to penetrate the paint film and reach the base of the painted plate, and 100 squares to paint film Formed.
A cellophane adhesive tape (manufactured by Nichiban) having a width of 24 mm was uniformly pressed on the cross-cut coating film with a fingertip so as not to generate air bubbles. Immediately holding one end of the pressure-sensitive adhesive tape, the pressure-sensitive adhesive tape was peeled off from the surface of the coating film by suddenly pulling the tape perpendicular to the surface of the coating film. The adhesion of the coating film was evaluated under the following criteria based on the area ratio of the coating film peeled off together with the adhesive tape.

[0173]

Examples 2 to 15 and 18 to 22 Clear paints were prepared in the same manner as in Example 1 except that the formulations shown in Tables 6 and 7 below were used, and the coating film performance was evaluated. The evaluation results are shown in Tables 6 and 7.

In Example 15, "F-244-09" manufactured by Nippon Unicar Co., Ltd. was used as the silicone polymer (d) -1. In the formula (II), R ¹ is a methyl group, R ² is a γ-glycidoxypropyl group / (trimethoxysilyl) ethyl group = 2/1,
R ³ , R ⁴ , R ⁵ and R ⁶ are a methyl group, l = 6, m = 2, n = 0, epoxy equivalent 318, and alkoxy equivalent 213.

In Example 19, "Denacol EX-314" manufactured by Nagase Kasei Kogyo Co., Ltd. was used as polyepoxide (c) -6.
(Glycidyl ether type epoxy resin of glycerin, epoxy equivalent: 145) was used.

Comparative Examples 1 to 3 Clear coating compositions were prepared in the same manner as in Example 1 except that the formulations shown in Table 7 below were used, and the coating film performance was evaluated. Table 7 shows the evaluation results.

Comparative Example 4 A clear paint was prepared in the same manner as in Example 1 except that a high solid type melamine paint manufactured by Nippon Paint Co., Ltd. having the composition shown in Table 5 below was used as the clear paint composition. The performance was evaluated. Table 7 shows the evaluation results.

[0179]

TABLE 5 Formulation resin portion Nippon Paint Co., Ltd. acrylic resin 75 (80% nonvolatile, hydroxyl value 100, acid value 10 and number average molecular weight 1800) by Mitsui Cytec melamine resin "Cymel 303" 20 (nonvolatile content 100% ) Melamine resin "Uban 120" manufactured by Mitsui Toatsu 22 (90% non-volatile content) Paratoluenesulfonic acid / diisopropanolamine = 1/1 1.8 UV absorber "Tinuvin 900" manufactured by Ciba-Geigy 2 Light stabilization manufactured by Sankyo "Sanol LS-440" 1 Monsanto surface conditioner "Modaflow" 0.1 Shell aromatic hydrocarbon solvent "Solvesso 100" 10

Examples 16 and 17 First, a clear coating composition was obtained in the same manner as in Example 1 with the composition shown in Table 7.

On the other hand, an electrodeposition paint (Powertop U-50 manufactured by Nippon Paint Co., Ltd.) and an intermediate coating paint (Olga P-2 manufactured by Nippon Paint Co., Ltd.) were each dried to a thickness of 0.8 mm on a phosphoric acid-treated steel sheet. An aqueous base paint (Example 1 of U.S. Pat. No. 5,183,504) was applied to a process test plate coated to 25 μm and 40 μm to a dry film thickness of 15 μm, and dried at 80 ° C. for 5 μm.
After drying for a minute, a base coating film was formed.

[0182] On top of that, the obtained clear coating composition was
Electrostatic coating machine by (Ransburg Gema Co. "Auto · REA") was coated to a dry film thickness atomization pressure 5 kg / cm ² is about 40 [mu] m, after about 7 minutes setting, at 140 ° C. 25 Bake for a minute.

The above aqueous base paint was compounded with the number average molecular weight of 12,000 and a hydroxyl value of 7 obtained in Preparation Example 1 of the same document.
Acrylic resin varnish with 0, acid value of 58 and non-volatile content of 50% 56.
2 parts, Mitsui Cytec Co., Ltd.
3 "15.0 parts, 21.5 parts of a urethane emulsion having an acid value of 16.2 and a nonvolatile content of 33%, an aluminum pigment paste" Alpaste 7 made of Toyo Aluminum Co., Ltd. having an aluminum flake content of 65%.
160N ”and 7.5 parts of Sakai Chemical's isostearate phosphate“ Phosphorex A-180L ”.

The performance of the obtained coating film was evaluated in the same manner as in Example 1. Table 7 shows the evaluation results.

[0185]

[Table 6]

¹ "Denacol EX-314" manufactured by Nagase Kasei Kogyo Co., Ltd. ² "F-244-09" manufactured by Nippon Unicar Co., Ltd.

[0187]

[Table 7]

¹ "Denacol EX-314" manufactured by Nagase Kasei Kogyo Co., Ltd. ² "F-244-09" manufactured by Nippon Unicar Co., Ltd. ³ High solid melamine paint manufactured by Nippon Paint Co., Ltd.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanobu Inoue 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (72) Inventor Yoshio Eguchi 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint (56) References JP-A-2-14867 (JP, A) JP-A-4-363374 (JP, A) JP-A-3-287650 (JP, A) JP-A-2-45577 (JP, A) Special Table Hei 1-501482 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 59/42 C09D 163/00-163/10 B05D 7/24 B05D 7/14

Claims (10)

(57) [Claims] (1) (a) 15 to 40% by weight of an ethylenically unsaturated monomer having an acid anhydride group and (2) 60 to 85% by weight of an ethylenically unsaturated monomer having no acid anhydride group. And an acrylic polyanhydride obtained by copolymerizing (ii)
A monoalcohol having 1 to 12 carbon atoms, obtained by reacting an acid anhydride group and a hydroxyl group in a molar ratio of 1/10 to 1/1 in a molar ratio, a carboxyl group and a carboxylic acid (B) a polyester polyol having 3 or more hydroxyl groups having an ester group and having an acid value of 5 to 300 mg KOH / g (solid content) and an acrylic polycarboxylic acid having a number average molecular weight of 500 to 8000; Acid value obtained by reacting the compound with an acid anhydride group-containing compound
~ 350mgKOH / g (solid content), hydroxyl value 5 ~ 100mgKOH / g, number average molecular weight 400 ~ 3500 and weight average molecular weight / number average molecular weight
5 to 70% by weight of a polyester polycarboxylic acid having 1.8 or less; and (c) an acrylic compound having a hydroxyl group and an epoxy group, having a hydroxyl value of 5 to 300 mgKOH / g, an epoxy equivalent of 50 to 700 and a number average molecular weight of 200 to 10,000. A high solid content curable resin composition containing 10 to 80% by weight of a polyepoxide (provided that component (a) to
The amount of (c) is based on the weight of the total solids in the curable resin composition. ). 2. The acrylic polyepoxide (c),
(c) (i) [Wherein, R is a hydrogen atom or a methyl group, and X is (Wherein, Y is a linear or branched alkylene group having 2 to 8 carbon atoms, m is an integer of 3 to 7, and q is an integer of 0 to 4), or ,formula Wherein R is a hydrogen atom or a methyl group, and n is 2 to 50
Is an integer. ). 5 to 70% by weight of a hydroxyl group-containing ethylenically unsaturated monomer having a structure represented by the following formula:
And (ii) an epoxy group-containing ethylenically unsaturated monomer 10 to 60
(Iii) from 0 to 85% by weight of ethylenically unsaturated monomers which do not share both hydroxyl and epoxy groups
2. An acrylic polyepoxide having a hydroxyl group and an epoxy group, obtained by copolymerizing
The curable resin composition according to the above. (3) (a) (i) 15 to 40% by weight of an ethylenically unsaturated monomer having an acid anhydride group and (2) 60 to 85% by weight of an ethylenically unsaturated monomer having no acid anhydride group. And an acrylic polyanhydride obtained by copolymerizing
A monoalcohol having 1 to 12 carbon atoms, obtained by reacting an acid anhydride group and a hydroxyl group in a molar ratio of 1/10 to 1/1 in a molar ratio, a carboxyl group and a carboxylic acid (B) a polyester polyol having three or more hydroxyl groups having an ester group and having an acid value of 5 to 300 mg KOH / g (solid content) and an acrylic polycarboxylic acid having a number average molecular weight of 500 to 8000; Acid value obtained by reacting the compound with an acid anhydride group-containing compound
~ 350mgKOH / g (solid content), hydroxyl value 5 ~ 100mgKOH / g, number average molecular weight 400 ~ 3500 and weight average molecular weight / number average molecular weight
5 to 70% by weight of a polyester polycarboxylic acid having 1.8 or less; and (c) (i) [Wherein, R is a hydrogen atom or a methyl group, and X is (Wherein, Y is a linear or branched alkylene group having 2 to 8 carbon atoms, m is an integer of 3 to 7, and q is an integer of 0 to 4), or ,formula Wherein R is a hydrogen atom or a methyl group, and n is 2 to 50
Is an integer. ). 5 to 70% by weight of a hydroxyl group-containing ethylenically unsaturated monomer having a structure represented by the following formula:
And (ii) an epoxy group-containing ethylenically unsaturated monomer 10 to 60
(Iii) from 0 to 85% by weight of ethylenically unsaturated monomers which do not share both hydroxyl and epoxy groups
And a hydroxyl value of 5 to 300 m obtained by copolymerizing
gKOH / g, epoxy equivalent 50-700 and number average molecular weight 200-
A high solids curable resin composition containing 10 to 80% by weight of an acrylic polyepoxide having a hydroxyl group and an epoxy group having 10,000 (provided that the component (a) to
The amount of (c) is based on the weight of the total solids in the curable resin composition. ). 4. The polyester polyol is obtained by ring-opening a lactone compound having 4 to 7 carbon atoms to a low molecular weight polyhydric alcohol having 3 to 16 carbon atoms and having 3 or more hydroxyl groups to thereby extend the chain. The curable resin composition according to claim 1 or 3, wherein 5. The low molecular weight polyhydric alcohol is selected from the group consisting of trimethylolpropane, trimethylolethane, 1,2,4-butanetriol, ditrimethylolpropane, pentaerythritol and dipentaerythritol. The curable resin composition according to the above. 6. The curable resin composition according to claim 4, wherein said lactone compound is selected from the group consisting of ε-caprolactone, γ-caprolactone, γ-valerolactone, δ-valerolactone, and γ-butyrolactone. 7. A clear coating composition comprising the curable resin composition according to claim 1 as a binder component. 8. The clear coating composition according to claim 7, further comprising crosslinked resin particles. 9. A step of applying a water-based or solvent-based base coating on an undercoated or intermediate-coated substrate; a step of applying the clear coating composition according to claim 7 thereon without curing the base coating film. And a step of curing the base coating film and the clear coating film by heating. 10. A coated article obtained by the method according to claim 9.