JPS583506B2 - High solid content paint composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to high solids coating compositions.

More specifically, it is characterized by containing a diester and/or monoester of an α,β-monoethylenically unsaturated dicarboxylic acid having an internal double bond, and a polymerizable monomer having a ring structure substituted with a carboxyl group and a methyl group. The present invention relates to a high solid content coating composition comprising a copolymer and an incyanate compound.

In recent years, there has been an increasing demand for paint compositions to be resource-saving and pollution-free.

In particular, it is common practice to reduce the solvent content and increase the solid content in paints, since this is advantageous in that conventional manufacturing or coating equipment can be used as is.

On the other hand, acrylic resin-based paint compositions, which are a type of paint composition, can be used in a wide range of applications because they provide coatings with excellent chemical resistance, solvent resistance, weather resistance, and various other mechanical properties. It is used in

However, the solid content concentration of currently used acrylic resin paints at the time of application is approximately 50% by weight or less, and attempts to further increase the solidity content have resulted in the following problems.

That is, in conventional products, in order to increase the solid content concentration and prevent the viscosity from increasing, it was necessary to extremely lower the molecular weight of the resin.

This resulted in drawbacks such as deterioration in coating film performance such as stain resistance, corrosion resistance, chemical resistance, and hardness.

Therefore, as a result of intensive studies in order to obtain a resin solution free from the above-mentioned problems, the present inventors found that α,
Diester and/or monoester of β-monoethylenically unsaturated dicarboxylic acid R1-O-CO-CH=CH-CO-O-R2...(1
) (where R1 and R2 are H or C1 to C10 alkyl groups) into the resin, a resin solution with high solid content concentration and low viscosity can be obtained without drastically lowering the molecular weight of the resin. The above monomer is used in combination with a polymerizable monomer having a ring structure represented by formula (2) and/or formula (3) (wherein R3 represents a C1 to C10 alkylene group or polymethylene group, and R4 represents H or CH3 group). As a result, the viscosity hardly increases, the viscosity is low, the solid content is high, and
The present invention was completed based on the discovery that the coating film is significantly superior in terms of coating performance such as hardness and stain resistance.

That is, the present invention provides the following: A(i) General formula R1-O-CO-CH=CH-CO-O-R2...(1)
(R1 and R2 are H or C1 to C10 alkyl groups) 5 to 50 parts by weight of diesters and monoesters of α,β-monoethylenically unsaturated dicarboxylic acids (11) General formula and/ or (R3 is a C1-C10 alkylene group or a polymethylene group, R4 is H or CH3 group) 3 to 40 parts by weight of a polymerizable monomer having a ring structure, (iii) α,β- (B ) isocyanate compound.

The diester or monoester of (1) α,β-monoethylenically unsaturated dicarboxylic acid shown in general formula (1), which is the starting material for the copolymer used in carrying out the present invention, has a low viscosity of the copolymer resin. It is effective for

R1 and R2 in the general formula of the monomer have 1 carbon number
It needs to be 0 or less.

If the number of carbon atoms is greater than 10, the polymerization reactivity decreases, it is difficult to obtain a copolymer resin with a uniform composition, and the viscosity also increases, which is not preferable.

Further, the diester and/or monoester of the α,β-monoethylenically unsaturated dicarboxylic acid represented by the general formula (1) must be copolymerized in the copolymer in an amount of 5 to 50 parts by weight.

If the amount of the monomer is less than 5 parts by weight, the effect cannot be sufficiently exhibited.

That is, it does not contribute to lowering the viscosity or improving the performance of the coating film.

On the other hand, when the monomer is contained in an amount of 50 parts by weight or more, coating film performance such as initial adhesion, impact resistance, and chemical resistance deteriorates, which is not preferable.

Diesters of α,β-monoethylenically unsaturated dicarboxylic acids represented by general formula (1) (specific examples of common esters include diethyl maleate, dibutyl maleate, dioctyl maleate, methyl maleate, ethyl maleate) , propyl maleate, hexyl maleate,
Examples include inbutyl maleate, pentyl maleate, diethyl fumarate, dibutyl fumarate, dioctyl fumarate, ethyldecyl fumarate, butyl octyl fumarate, and the like.

These may be used alone or as a mixture of two or more.

In producing the copolymer represented by item (A) in the present invention, a polymerizable monomer having a methyl-substituted ring structure represented by general formula (2) or general formula (3) is used.

This monomer can lower the viscosity of the resulting resin solution and increase the solid content compared to the case where a corresponding polymerizable monomer having a ring structure without a methyl group is used.

Moreover, it is also excellent in improving coating film performance such as hardness and stain resistance.

The polymerizable monomer having a ring structure represented by the general formulas (2) and (3) must be copolymerized in the copolymer in an amount of about 3 to 40 parts by weight.

That is, when the monomer is used in an amount of 3 parts by weight or less, the stain resistance and hardness of the coating film are reduced, and no effect on coating performance is observed due to the use of the monomer.

On the other hand, if the monomer is contained in an amount of 40 parts by weight or more, coating film performance such as initial adhesion, impact resistance, and alkali resistance deteriorates, which is not preferable.

Specifically, the polymerizable monomers having a ring structure represented by general formulas (2) and (3) include methyltetrahydrophthalic anhydride, methyltetrahydrophthalic acid, methylhexahydrophthalic anhydride, methylhexahydrophthalic acid, etc. and 2-
Hydroxyethyl (meth)acrylate, 2-hydroxybropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate ) acrylate, 5-hydroxypentyl (meth)acrylate, 6-
α,β- such as hydroxyhexyl (meth)acrylate, neopentyl glycol mono(meth)acrylate, etc.
It is a monoester of a monoethylenically unsaturated carboxylic acid with a hydroxyalkyl ester.

These may be used alone or as a mixture of two or more.

(iii) α used in producing the copolymer;
, β-monoethylenically unsaturated carboxylic acid hydroxyalkyl ester must be copolymerized in the copolymer at a ratio of 5 to 50 parts by weight, and the monomer amount is 5 to 50 parts by weight.
When the monomer is less than 50 parts by weight, the crosslinking density is low in combination with the isocyanate compound, resulting in poor solvent resistance and chemical resistance of the coating film.On the other hand, when the monomer is more than 50 parts by weight, the combination with the above-mentioned crosslinking agent In this case, the crosslinking density becomes too high, resulting in poor flexibility of the coating film, which is also economically unfavorable.

Specific examples of the hydroxyalkyl ester of α,β-monoethylenically unsaturated carboxylic acid used in the present invention include 2-hydroxyethyl (meth)acrylate,
2-Hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate
Acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, neopentyl glycol mono(meth)acrylate,
3-Butoxy-2-hydroxybropyl (meth)acrylate, 2-hydroxy-1-phenylethyl (meth)
Acrylate, polypropylene glycol mono(meth)
Examples include acrylate, glycerin mono(meth)acrylate monohalf fumarate, and hydroxyalkyl esters of α,β-monoethylenically unsaturated carboxylic acids.

These may be used alone or as a mixture of two or more.

In the present invention, when producing the copolymer, other copolymerizable monomers ((■) component) may be added as necessary.
Use.

Specific examples include α,β-monoethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid; methyl (meth)acrylate, ethyl (meth)acrylate, n- Propyl (meth)acrylate, Isobrovir (meth)acrylate,
n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate,
Isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate 1-,n-octyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, etc. Alkyl esters of acrylic acid or methacrylic acid; N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, N-n-bropoxymethyl (meth)acrylamide, N-imbropoxymethyl (meth)acrylamide
α, β-mono such as acrylamide, N-n-butoxymethyl (meth)acrylamide, N-sec-butoxymethyl (meth)acrylamide, N-t-butoxymethyl (meth)acrylamibe, N-inbutoxymethyl (meth)acrylamide, etc. N-alkoxymethylated products of ethylenically unsaturated carboxylic acid amides; or N-methylolated products thereof; other N,N'-dinothylaminoethyl (
Monomers such as meth)acrylate, glycidyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl methacrylate, pendyl methacrylate, styrene, vinyltoluene, α-methylstyrene, (meth)acrylic nitrile, and vinyl acetate can be mentioned.

The above monomers may be used depending on the purpose and use of the coating composition.
You may use one species or a combination of two or more as appropriate.

In the present invention, a copolymer is obtained from the monomers (1) to (iv) above by a conventional solution polymerization method.

Examples of the polymerization solvent used in the solution polymerization method include:
Alcohols such as methanol, ethanol, n-propanol, and impropanol; Ethylene glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol-monobutyl ether, and ethylene glycol monoethyl ether acetate; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,
Diethylene glycol derivatives such as diethylene glycol monobutyl ether; Aromatic hydrocarbons such as toluene, xylol, and aromatic petroleum naphtha; Esters such as methyl acetate, ethyl acetate, and butyl acetate; Ketones such as methyl ethyl ketone and methyl isobutyl ketone, etc. use

These polymerization vehicles may be used alone or in an appropriate combination of two or more.

However, when an incyanate compound containing a free incyanate group in the molecule is used as a crosslinking agent, as will be described later, the use of a solvent containing an active hydrogen group should be avoided.

In addition, examples of the polymerization initiator used include penzoyl peroxide, t-butyl perbenzoate, t-
Organic peroxides such as butyl peroxide, hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, t-butyl peroctoate, t-butyl perpenzoate, or azobisisobutyronitrile, azodiisobutyric acid Examples include azo compounds such as nitrile.

These polymerization initiators may be used alone or in an appropriate mixture of two or more.

If necessary, chain transfer agents such as dodecylmerbutane, 2-ethylhexyl thioglycolate, carbon tetrachloride, etc. may be used to adjust the molecular weight.

The weight average molecular weight of the copolymer used in the present invention is 1000
~30000, preferably 2000~10000
It is.

When the solid content concentration of a resin solution whose copolymer has a weighted average molecular weight of 30,000 or more is increased, the viscosity increases significantly, making it difficult to achieve the object of the present invention.

On the other hand, when the weight average molecular weight is 1000 or less, the coating film performance is not sufficient.

The incyanate compound used as a crosslinking agent in the present invention refers to an incyanate compound having two or more incyanate groups in one molecule, or a part or All are blocked isocyanate compounds masked with blocking agents.

In the present invention, the incyanate compound is preferably used in a ratio of hydroxyl group in the copolymer/incyanate group in the isocyanate compound=1/1.3 to 1\0.5.

When the hydroxyl group/isocyanate group of the copolymer is larger than 1/0.5, the crosslinking is not sufficiently performed, and solvent resistance, chemical resistance, etc. tend to decrease; When is smaller than 1/1.3, excessive isocyanate groups remain unreacted in the coating film, resulting in poor water resistance, etc., which is not preferable.

Specific examples of compounds used in the present invention include ethylene diisocyanate, propylene diisocyanate,
Tetramethylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,
6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triincyanate, 4,4''-diphenylmethane diisocyanate, 3,3'-dimethyl -4,4
Polyisocyanates such as '-diphenylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, inphorone diisocyanate, lysine isocyanate, and an excess of the induanate compounds, such as ethylene glycol, propylene glycol, 1,3 - with low molecular polyols such as butylene glycol, neopentyl glycol, 2,2,4-1-limethyl 1,3-pentadiol, hexamethylene glycol, cyclohexanedimethanol, trimethylolpropane, hexanetriol, glycerin, pentaerythritol, etc. 2 tube capacity obtained by addition reaction, reaction
polyisocyanates, polyisocyanates with a puret structure, polyisocyanates with allophanate bonds, etc.

Further, the blocked isocyanate compound is a reaction product of the above incyanate compound and the blocking agent described below.

The blocking agents include phenols such as phenol and cresol, alcohols such as methanol, benzyl alcohol, and ethylene glycol monoethyl ether, active methylenes such as methyl acetoacetate and dimethyl malonate, and acid amides such as acetanilide and acetamide. Other imide-based, amine-based, imidazole-based, urea-based, carbamate-based, imine-based, oxime-based, mercabutan-based,
There are sulfite-based, lactam-based, etc.

If necessary, an epoxy resin may be used in combination with an incyanate compound in order to obtain a coating film with even better adhesion, corrosion resistance, physical properties, and the like.

The epoxy resin (30 parts by weight or less, preferably 5 to 20 parts by weight) is used per 100 parts by weight of the above copolymer.

If the amount of the epoxy resin used is 30 parts by weight or more, it is not preferable from the viewpoint of yellowing and weather resistance of the coating film.

The epoxy equivalent weight (Durham number of the resin containing 1 gram equivalent of epoxide) of the epoxy resin that can be used in the present invention is about 1000 or less, and its average molecular weight is usually 1400 or less, preferably in the range of 700 to 1000. be.

When the composition of the present invention is used as a two-component room-temperature curable composition, it is necessary to use a hydroxyl group-containing epoxy resin in order to sufficiently cure the copolymer and incyanate compound in the composition. preferable.

Examples of the epoxy resin used in combination in the present invention include polyglycidyl ethers of bisphenols, polyether derivatives of polyhydric phenols, fatty acid-modified epoxy resins, and the like.

Furthermore, in the composition of the present invention, anticorrosion pigments, coloring pigments, extender pigments, other additives, etc. may be added in any desired amounts as required, and kneading methods such as a sand mill, a ball mill, etc.
A paint composition can be obtained by mixing and kneading using a roll mill or the like.

The composition of the present invention thus obtained can be applied to metals such as cold-rolled steel, aluminum, brass, and chemically treated metals by common coating methods such as roll coating, spray coating, and electrostatic coating. , other substrates such as glass, asbestos, cement shingles, leather, wood,
Can be applied to paper, textiles, etc.

In addition, in the composition of the present invention, incyanate compounds having free isocyanate groups (including partially blocked block isocyanate compounds) are used as crosslinking agents.
When using the crosslinking agent, the crosslinking agent is mixed with the copolymer at the time of use, which is a so-called two-component type.

On the other hand, when a blocked isocyanate compound in which all incyanate groups are blocked is used as a crosslinking agent, a so-called one-component type can be used.

The two-component composition is formed into a coating film by drying at room temperature or forced drying, while the one-component composition is dried at a temperature of 80 to 200°C.
It can be formed into a coating film by heating and drying for 10 to 40 minutes.

The coating film thus obtained has good hardness, adhesion, alkali resistance,
It has excellent stain resistance.

The present invention will be further explained below with reference to Examples.

"Part 4" or "%" is expressed as "part by weight" or "% by weight."

Example 1 Method for producing copolymer 30 parts of styrene, 20 parts of butyl acrylate, 15 parts of 2-hydroxyethyl methacrylate, 5 parts of acrylic acid,
20 parts of dibutyl fumarate, methi. From 100 parts of a monomer mixture consisting of 10 parts of the reaction product of hexahydrophthalic anhydride and 2-hydroxyethyl acrylate, 5 parts of azobisisobutyronitrile, 5 parts of t-butyl peroctoate, and 1 part of t-butyl perbenzoate. 11 parts of the initiator was added to 46 parts of ethylene glycol monoethyl ether acetate, which was a polymerization solvent, and polymerization was carried out at 120° C. for 8 hours.

The polymerization method was a normal dropping method, and the dropping time was 2 hours.

The properties of the obtained copolymer resin are non-volatile, 67.8%,
Acid value 33.1, viscosity (20°C) 19.9 Stokes,
The weight average molecular weight was approximately 3,620.

Preparation and painting of paint 16 parts of incyanate compound [Sumidur N75, product name manufactured by Sumitomo Bayer AG; NCO content 16.5%] was mixed with 100 parts of the resin solution obtained by the above method at the time of painting, Using toluene as a diluent, it was diluted and prepared according to the coating viscosity.

The above-prepared paint was applied to a zinc phosphate treated plate (0.8
The performance of the coating film was investigated after spraying it on a surface of 150 mm x 7 0 x 150 mm and drying it at room temperature for one week. The results are shown in Table 1.

Example 2 Production of copolymer Styrene 30 parts, butyl acrylate 15 parts, 2-hydroxyethyl methacrylate 15 parts, dibutyl fumarate 20 parts, reaction product of methylhexahydrophthalic anhydride and 2-hydroxy, ethyl acrylate 20 parts Polymerization was carried out in the same manner as in Example 1 except that 100 parts of the monomer mixture consisting of 100 parts of the monomer mixture of 100 parts of the monomer mixture of

The characteristic value of the obtained copolymer resin is that the nonvolatile content is 68.1%.
It had an acid value of 27.3, a viscosity (at 20° C.) of 20.1 Stokes, and a weight average molecular weight of about 3,800.

Preparation and painting of paint 16 parts of an isocyanate compound (same as in Example 1) was mixed with 100 parts of the resin solution obtained in the above method at the time of painting, and diluted to the coating viscosity using toluene as a diluent.

The above mixed paint was applied to a zinc phosphate treated plate (0.8X
70 x 150 mm) and dried at room temperature for one week, the performance of the coating film was examined and the results are shown in Table 1.

Example 3 Copolymer production method 30 parts of methyl methacrylate, 20 parts of butyl acrylate
100 parts of a monomer mixture consisting of 15 parts of 2-hydroxyethyl methacrylate, 5 parts of acrylic acid, 20 parts of dibutyl fumarate, and 10 parts of the reaction product of methylhexahydrophthalic anhydride and 2-hydroxyethyl acrylate.
Polymerization was carried out in the same manner as in Example 1 except that the monomer mixture of Example 1 was used for the same amount.

The characteristic values of the obtained resin are non-volatile content 68.8% and acid value 36.
．． 5. The viscosity (at 20° C.) was 18.1 Stokes, and the weight average molecular weight was about 2,140.

Preparation and Painting of Paint Using the resin solution obtained by the above method, a paint was prepared in the same formulation process as in Example 1, and was painted and dried in the same manner.

Table 1 shows the performance results of the coating film thus obtained.

Example 4 Copolymer production method Styrene 29 parts, butyl acrylate 28 parts, 2-hydroxyethyl methacrylate 115 parts, acrylic acid 3 parts,
20 parts of dibutyl maleate, 100 parts of a monomer mixture consisting of 5 parts of the reaction product of methylhexahydrophthalic anhydride and 2-hydroxyethyl acrylate, 5 parts of azobisisobutyronitrile, and 5 parts of t-butyl peroctoate. , 11 parts of an initiator consisting of 1 part of t-butyl perbenzoate were added to 46 parts of triol as a polymerization solvent, and 1
Polymerization was carried out at 20°C for 8 hours.

The polymerization method was a conventional dropping method, and the dropping time was 2 hours.

The characteristic value of the obtained copolymer resin is that the nonvolatile content is 67.0%.
, acid value 28.0, viscosity (20°C) 11.4 Stokes,
The weight average molecular weight was approximately 4,300.

Preparation and painting of paint 16 parts of an isocyanate compound (same as in Example 1) was mixed with 100 parts of the resin solution obtained by the above method at the time of painting, and the paint was prepared, painted and dried in the same manner as in Example 1. I did it.

Table 1 shows the performance results of the coating film thus obtained.

Example 5 Copolymer production method Styrene 29 parts, butyl acrylate 38 parts, 2-hydroxyethyl methacrylate 15 parts, acrylic acid 3 parts,
Polymerization was carried out in the same manner as in Example 4 except that the monomer mixture of Example 4 was replaced with 10 parts of dibutyl maleate and 100 parts of a monomer mixture consisting of 5 parts of the reaction product of methylhexahydrophthalic anhydride and 2-hydroxyethyl acrylate. Ta.

The characteristic value of the obtained copolymer resin is that the nonvolatile content is 68.8%.
, acid value 25.2, viscosity (20°C) 23.9 Stokes,
The weight average molecular weight was approximately 5,480.

Preparation and coating of paint For 100 parts of the resin solution obtained by the above method, block isocyanate compound [Takenate B-820NS
-U, Takeda Pharmaceutical ■Product: NCO content 4.22%
) 64.3 parts, epoxy resin solution [Epicoat #100
1.Product name: 70% xylol solution manufactured by Shell Chemical ■5
A coating composition was prepared by mixing the following parts.

When painting, use toluene as a diluent to dilute to the coating viscosity, and apply zinc phosphate treated steel plate (0.8 x 70 x 150 m
m) After spray painting on top, it was heated and dried at 150°C for 20 minutes.

Table 1 shows the performance results of the coating film thus obtained.

Comparative Example 1 Copolymer production method 30 parts of styrene, 30 parts of butyl acrylate, 15 parts of 2-hydroxyethyl methacrylate, 5 parts of acrylic acid,
Monomer mixture 1 consisting of 20 parts of dibutyl fumarate
Polymerization was carried out in the same manner as in Example 1 except that 00 parts of the monomer mixture of Example 1 was used.

The characteristic values of the obtained resin are non-volatile content 69.0% and acid content 25%.
．． 1, viscosity (20° C.) of 18.5 Stokes, and weight average molecular weight of about 3,770.

Preparation and coating of paint Using the resin solution obtained by the above method, a paint was prepared according to the same formulation as in Example 1, and painted and dried in the same manner.

Table 1 shows the performance results of the coating film thus obtained.

Comparative Example 2 Method for producing copolymer 30 parts of styrene, 30 parts of butyl acrylate, 15 parts of 2-hydroxyethyl methacrylate, 5 parts of acrylic acid,
Polymerization was carried out in the same manner as in Example 1 except that 100 parts of a monomer mixture consisting of 20 parts of 2-ethylhexyl acrylate was used in place of the monomer mixture of Example 1.

The characteristic values of the obtained resin are non-volatile content 68.0% and acid value 23.
．． 1. The viscosity (20° C.) was 38.4 Stokes, and the weight average molecular weight was about 3950.

Preparation and Painting of Paint Using the resin solution obtained by the above method, a paint was prepared using the same formulation method as in Example 1, and painting and drying were carried out in the same manner.

Table 1 shows the performance results of the coating film thus obtained.

Comparative Example 3 Copolymer production method Styrene 30 parts, butyl acrylate 20 parts, 2-hydroxyethyl methacrylate 15 parts, acrylic acid 5 parts,
20 parts of dibutyl fumarate, reaction product of hexahydrophthalic anhydride and 2-hydroxyethyl acrylate 1
Polymerization was carried out by replacing the monomer mixture of Example 1 with 100 parts of a monomer mixture consisting of 0 parts.

The characteristic values of the obtained resin are non-volatile content 69.1% and acid value 34.
．． 9. The viscosity (20° C.) was 35.0 Stokes, and the weight average molecular weight was about 2,900.

Preparation and Painting of Paint Using the resin solution obtained by the above method, a paint was prepared according to the same formulation as in Example 1, and painted and dried in the same manner.

Table 1 shows the performance results of the coating film thus obtained.

It is clear from Table 1 of the comparative test results that the copolymer having the composition of the present invention has a very low viscosity even though it has a considerable molecular weight. It can be seen that a coating composition with a low oxidation rate can be obtained, and the resulting coating film has excellent properties such as hardness, initial adhesion, alkali resistance, and stain resistance.

Claims (1)

[Scope of Claims] 1 (a) (1) A diester of α,β-monoethylenically unsaturated dicarboxylic acid represented by the general formula (wherein R1 and R2 represent H or a C1 to C10 alkyl group) and /or monoester 5-50
Parts by weight, (11) 3 to 40 polymerized parts of a polymerizable monomer having a ring structure represented by the general formula and/or (wherein R3 is a C1 to C1o alkylene group or polymethylene group, and R4 is a H or CH3 group) , (iii) 5 to 50 parts by weight of hydroxyalkyl ester of α,β-monoethylenically unsaturated carboxylic acid, and (■) optionally 0 to 50 parts by weight of other copolymerizable monomers of the group.
87 parts by weight of a copolymer obtained from the following, and (B) an isocyanate compound. 2 α having an internal double bond represented by general formula (1),
The diester and/or monoester of β-monoethylenically unsaturated dicarboxylic acid has an alkyl group with 1 carbon number.
1 to 10 dialkyl and/or monoalkyl esters of maleic or fumaric acid
Claim 1 which is a species or a mixture of two or more species
The high solid content paint composition described in 1. 3 The polymerizable monomer having a carboxyl group- and methyl group-substituted ring structure represented by general formulas (2) and/or (3) is methyltetrahydrophthalic anhydride, methyltetrahydrophthalic acid, methylhexahydrophthalic anhydride, or At least one type of methyl hexaphthalic acid and α
, H-noethylenically unsaturated carboxylic acid with a hydroxyalkyl ester, or a mixture of two or more thereof. 4 The weight average molecular weight of the copolymer is 1000 to 3000
The high solid content coating composition according to claim 1, wherein the solid content is 0. 5. The mixing ratio of the copolymer and the incyanate compound is (hydroxyl group in the copolymer)/(isocyanate group in the isocyanate compound) = 1/1.3 to 1/0.5. A high solid content coating composition according to claim 1.