JP2001316617A - Polyester-based aqueous coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester-based aqueous coating composition which can form a coating film excellent in processibility, especially one suitable for can interior coating. SOLUTION: This coating composition is prepared by neutralizing a mixture mainly comprising (A) a carboxylated polyester resin which is prepared by the esterification of a polyhydric alcohol component containing at least 60 mol% ethylene glycol and a polybasic acid component containing at least 80 mol% aromatic polycarboxylic acid and has a number average mol.wt. of 1,000-20,000 and an acid value of 10-170 mgKOH/g, (B) a water-insoluble epoxy resin, and (C) a hydrophobic solvent, with a neutralizing agent and (D) dispersing or dissolving the neutralized mixture in an aqueous medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to processability, safety,
The present invention relates to a water-based coating composition capable of forming a coating film having excellent hygiene properties, and more particularly to a polyester-based water-based coating composition suitable for coating the inner surface of a can. The coating composition of the present invention,
It can be applied to industrial uses such as pre-coated metal.

[0002]

2. Description of the Related Art Conventionally, as a water-based paint for the inner surface of a can, a product obtained by grafting a high-molecular-weight bisphenol A type epoxy resin with a high acid value acrylic resin, neutralizing with an alkanolamine and dispersing in water is generally used. It has been used in the market and has gained a reputation in the market. However, in recent years, bisphenol A has become an endogenous endocrine disrupting chemical (environmental hormone).
There is a demand for an aqueous paint from which the bisphenol A is not eluted at all.

As such an aqueous paint, for example, it is conceivable to use a polyester resin as a base resin component. For example, JP-A-61-37811 proposes a thermosetting resin composition obtained by emulsifying a water-soluble polyester resin and an epoxy resin. In this composition, it is stated that the dispersing ability is enhanced by using a hydrophilic solvent for the polyester resin, but the performance such as film forming properties and processability for the inner surface of the can was insufficient. When a polyester resin composition that ensures performance such as processability is used, there is a problem that emulsion stability after water dispersion cannot be ensured.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a composition comprising a specific carboxyl group-containing polyester resin, a water-insoluble epoxy resin, and a hydrophobic solvent is water-soluble. The present inventors have found that a coating material obtained by dispersing can form an excellent coating film for the inner surface of a can without the above-mentioned problems, and have completed the present invention.

That is, the present invention relates to (A) an esterified product comprising a polyhydric alcohol component containing at least 60 mol% of ethylene glycol and a polybasic acid component containing at least 80 mol% of an aromatic polycarboxylic acid. Molecular weight of 1,000-2
(D) a neutralizing agent comprising a mixture containing a carboxyl group-containing polyester resin having an acid value of 10 to 170 mg KOH / g, a water-insoluble epoxy resin (B), and a hydrophobic solvent (C) as a main component. The present invention provides a polyester-based aqueous coating composition characterized by being neutralized with and dispersed or dissolved in an aqueous medium.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a carboxyl group-containing polyester resin (A) is prepared by adding ethylene glycol to 6
It is an esterified product composed of a polyhydric alcohol component containing 0 mol% or more and a polybasic acid component containing 80 mol% or more of aromatic polycarboxylic acid, and contains a carboxyl group in the resin.

The polyester resin comprises the following (1) and (2)
Or it can be obtained by the method of (3). (1) a method of subjecting a polybasic acid component and a polyhydric alcohol component to an esterification reaction under the condition that the carboxyl group becomes excessive relative to the hydroxyl group; (2) a method of converting the polybasic acid component and the polyhydric alcohol component to the carboxyl group A method in which an acid anhydride is reacted with a polyester polyol obtained by reacting under a condition in which hydroxyl groups are excessive, (3) alcoholic acid reaction with a polyhydric alcohol using a high molecular weight polyester such as polyethylene terephthalate or polybutylene terephthalate as a starting material. And then subjecting the polybasic acid component and, if necessary, the polyhydric alcohol component to an esterification reaction under the condition that the carboxyl group becomes excessive.

Examples of the polybasic acid component constituting the polyester resin include (phthalic anhydride), isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, tetrahydro (anhydride) phthalic acid, hexahydro (anhydride) phthalic acid, and hexahydroisophthalic acid. Acid, hexahydroterephthalic acid, 4-methylhexahydro (anhydride) phthalic acid, 3-
One or more dibasic acids selected from methyltetrahydro (anhydride) phthalic acid, (anhydride) succinic acid, fumaric acid, adipic acid, azelaic acid, sebacic acid, (anhydride) maleic acid and the like, and lower alkyl esters of these acids Are mainly used, and benzoic acid, crotonic acid,
monobasic acids such as pt-butylbenzoic acid and other various fatty acids; tribasic or higher polybasic acids such as (anhydrous) trimellitic acid, methylcyclohexentricarboxylic acid, (anhydrous) pyromellitic acid, and butanetricarboxylic acid; Used together.
Among these, as the polybasic acid component, the aromatic polycarboxylic acid is preferably at least 80 mol%, preferably 9 mol%, based on the total polybasic acid.
It is essential to contain 0 mol% or more from the viewpoint of hydrolysis resistance stability.

The polyhydric alcohol component includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-
Butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 2-methylpropanediol, 3-methylpentanediol, 1,4
-Hexanediol, 1,5-pentaneddiol, 1,
6-hexanediol, 1,9-nonanediol, 2,
2-diethyl-1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2-
Ethyl-2-butyl-1,3-propanediol, 2-
Ethyl-2-isobutyl-1,3-propanediol,
Aliphatic glycols such as 2,2,4-trimethyl-1,6-hexanediol; 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4
Alicyclic glycols such as cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and spiroglycol; aromatic glycols such as ethylene oxide adducts and propylene oxide adducts of bisphenol compounds; Polyether polyols such as polyethylene glycol, polypropylene glycol and polytetrabutylene glycol, dihydric alcohols such as polyurethane polyols obtained by reacting glycols and polyisocyanate compounds are mainly used, and further glycerin, trimethylol ethane, if necessary. Trihydric or higher polyhydric alcohols such as trimethylolpropane and pentaerythritol can be used in combination. These polyhydric alcohols can be used alone or in combination of two or more. Glycols containing an ester group in the molecule, such as bishydroxyethyl terephthalate, can also be used. Among these, as the polyhydric alcohol, it is essential that ethylene glycol be contained in the total polyhydric alcohol in an amount of 60 mol% or more, preferably 70 mol% or more, in view of the hardness of the coating film, particularly, in the case of cans, from the viewpoint of flavor retention. In addition, it is preferable to use butylene glycol in combination from the viewpoint of film properties such as processability. For glycols containing ester groups in the molecule,
The addition should be made by the molar ratio of the minimum unit monomer (for bishydroxyethyl terephthalate, terephthalic acid 1
Moles and 2 moles of ethylene glycol).

The above-mentioned esterification or transesterification of both components can be carried out by a method known per se.

In the above method (1), the polybasic acid component and the polyhydric alcohol component are subjected to a direct esterification method or a transesterification method by a conventional method under the condition that the carboxyl group is excessive with respect to the hydroxyl group. The carboxyl group-containing polyester resin (A) can be obtained. At this time, the proportion of the trifunctional or higher functional component based on the total of the polybasic acid component and the polyhydric alcohol component is preferably 12 mol% or less, more preferably 7 mol% or less, from the viewpoint of processability. is there.

In the above method (2), the polybasic acid component and the polyhydric alcohol component are subjected to a direct esterification method or a transesterification method by a conventional method under the condition that a hydroxyl group is excessive relative to a carboxyl group. Obtain a polyester polyol. During the production of this polyester polyol,
Based on the sum of the polybasic acid component and the polyhydric alcohol component
It is suitable from the viewpoint of workability and the like that the proportion of the trifunctional or higher functional component is 12 mol% or less, preferably 7 mol% or less. The carboxyl group-containing polyester resin (A) can be obtained by reacting the obtained polyester polyol with an acid anhydride. Examples of the acid anhydride to be reacted with the polyester polyol include phthalic anhydride, succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, and trimellitic anhydride.

In the above-mentioned method (3), a high-molecular-weight polyester is used as a starting material, alcoholicsis is carried out with a polyhydric alcohol, and then a polybasic acid component and, if necessary, a polyhydric alcohol component are prepared under conditions in which the carboxyl group becomes excessive. Below, the carboxyl group-containing polyester resin (A) can be obtained by a direct esterification method or a transesterification method according to a conventional method. At this time, the proportion of the trifunctional or higher functional component based on the total of the polybasic acid component and the polyhydric alcohol component is preferably 12 mol% or less, more preferably 7 mol% or less, from the viewpoint of processability. is there.

In the above methods (1), (2) and (3), the reaction by the direct esterification method or the transesterification method is carried out by increasing the pressure or reducing the pressure or by flowing an inert gas to accelerate the reaction. Can also. Further, at the time of the reaction, an organic metal catalyst such as di-n-butyltin oxide or the like can be used as an esterification catalyst. Industrially, the direct esterification method is usually advantageously used. Among the above methods (1) to (3), the method (1) is preferable from the viewpoint of easy adjustment of molecular weight and acid value.

The carboxyl group-containing polyester resin (A) has a number average molecular weight of 1,000 to 20,000, preferably 2,000 to 10,000, from the viewpoint of processability, flavor retention, curability, stability and the like. , Acid value is 10 to 170
mgKOH / g, preferably 25-75 mgKOH / g
The mixing ratio of the acid component and the alcohol component, the type of each component, and the like are appropriately selected so as to obtain a polyester resin having this property. Further, the carboxyl group-containing polyester resin (A) has a hydroxyl value of 10 mgKOH / g or less and a glass transition temperature of 0 ° C or more, preferably 20 to 80 ° C, in view of dispersibility and curability. ing.

In the present invention, the water-insoluble epoxy resin (B) is included as a curing agent component. The epoxy resin (B) has at least two or more epoxy groups in one molecule. For example, aromatic polyglycidyl ether compounds such as resorcinol diglycidyl ether and hydroquinoline diglycidyl ether; aliphatic alcohols and Polyglycidyl ether compounds of alicyclic alcohols; diglycidyl orthophthalate, diglycidyl isophthalate, diglycidyl terephthalate, glycidyl ester p-oxybenzoate, diglycidyl tetrahydrophthalate,
Glycidyl ester compounds such as diglycidyl hexahydrophthalate and diglycidyl succinate; reaction of epichlorohydrin with bisphenols such as bisphenol F, bisphenol A, 1,1-bis (4-hydroxyphenyl) ethane and bisphenol S Bisphenol type epoxy resin obtained; Novolak type epoxy resin such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, phenol glyoxal type epoxy resin having a large number of epoxy groups in the molecule; triglycidyl isocyanurate; brominated epoxy Resins; glycidylamine type epoxy resin; naphthalene type epoxy resin; hydantoin type epoxy resin; diglycidyl ether of hydrogenated bisphenol A and its epoxy resin Goma; epoxidized polybutadiene; 3,4-epoxycyclohexylmethyl-3,4-
An alicyclic epoxy group-containing compound such as epoxycyclohexanecarboxylate; and an acrylic resin having an epoxy group-containing monomer such as glycidyl (meth) acrylate or 3,4-epoxycyclohexyl (meth) acrylate as a copolymer component. Among these, an epoxy resin containing no free bisphenol A is preferable for use in the inner surface of a can, and a novolak type epoxy resin is particularly preferable from the viewpoint of food hygiene and coating film performance. In addition, in the case where the free bisphenol A can be completely removed by purification even in the inner surface of the can, a bisphenol A type epoxy resin obtained by a reaction between bisphenol A and epichlorohydrin may be used.

When using the epoxy resin (B),
The equivalent ratio of the carboxyl group in the carboxyl group-containing polyester resin (A) / the epoxy group in the epoxy resin (B) is usually from 1 / 0.3 to 1 / 1.5, preferably from 1 / 0.3.
It is desirable to mix them in the range of 0.5 to 1 / 1.0.

In the present invention, the hydrophobic solvent (C) serves to control viscosity during dispersion and to suppress crystallization of the resin and to act as a film-forming aid for continuous film formation. Examples of the solvent (C) include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate, butyl acetate and octyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and cyclic ketones such as cyclohexanone and isophorone. Ether alcohols such as ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, and propylene glycol phenyl ether; alcohols such as 2-ethylhexyl alcohol, hexyl alcohol, butyl alcohol, and benzyl alcohol; Petroleum-based refining solvents such as "00" (manufactured by Cosmo Oil) and "Solvesso 150" (manufactured by Esso Oil), "Texanol" (manufactured by Eastman), "Kyowasol M" (manufactured by Kyowa Hakko) and the like. These can be used alone or in combination of two or more. Of these,
Particularly, cyclohexanone is preferred.

The amount of the hydrophobic solvent (C) used is suitably from 1 to 200 parts by weight, preferably from 5 to 100 parts by weight, per 100 parts by weight of the resin solids. The amount used is 1
If the amount is less than part by weight, the film-forming properties and smoothness of the coating film become insufficient, while if it exceeds 200 parts by weight, a stable emulsion cannot be obtained, which is not preferable. In addition, even when the amount of the hydrophobic solvent (C) used exceeds the above range, the emulsion is dispersed in the water-dispersed emulsion by an ordinary method such as azeotrope or reduced pressure because of ease of production at the time of preparing the mixture before water dispersion. It can be adjusted within the range.

In addition to the hydrophobic solvent (C), a water-miscible organic solvent can be used in the mixture before dispersion in water, if necessary. Examples of the water-miscible organic solvent include butyl cellosolve, monomethyl carbitol, dimethyl carbitol, monoethyl carbitol, propylene glycol monomethyl ether, acetone, methyl alcohol, ethyl alcohol, and isopropyl alcohol. The amount of the water-miscible organic solvent used is preferably 40% by weight or less, more preferably 20% by weight or less of the total amount of the solvent used.

In the present invention, a mixture containing a carboxyl group-containing polyester resin (A), an epoxy resin (B) and a hydrophobic solvent (C) as main components is neutralized with a neutralizing agent (D) to obtain an aqueous solution. It is dispersed in the medium.

As the neutralizing agent (D), basic compounds such as amines and ammonia are preferably used. Examples of the amines include trimethylamine, triethylamine,
Alkylamines such as tributylamine; alkanolamines such as dimethylethanolamine, methyldiethanolamine, diethanolamine and aminomethylpropanol; and cyclic amines such as morpholine, alkylmorpholine, methylpiperazine and ethylpiperazine. Triethylamine and dimethylethanolamine are preferred. The degree of neutralization is
Although it is not particularly limited, it is usually 0.1 to 2.0 equivalents, preferably 0.2 to 1.0 equivalent to the carboxyl group of the resin (A).
It is preferably in the range of 0 equivalents.

To neutralize and disperse the mixture containing the carboxyl group-containing polyester resin (A) in an aqueous medium,
For example, a method in which a mixture containing a carboxyl group-containing polyester resin (A) is gradually added to an aqueous medium containing a neutralizing agent (D) while stirring, a method in which a carboxyl group-containing polyester resin (A) is used. Is neutralized with a basic compound and then an aqueous medium is added to the neutralized product under stirring, or the neutralized product is added to the aqueous medium. Further, if necessary, the solvent amount in the coating material can be appropriately controlled by removing the solvent together with water under reduced pressure.

The aqueous coating composition of the present invention may further contain, if necessary, a curing catalyst, an antifoaming agent, a lubricity-imparting agent, a modified resin, pigments, a coagulation inhibitor, a leveling agent, A rheology control agent, a fragrance and the like can be appropriately blended. The organic solvents listed in the above description may be appropriately blended after the aqueous coating for adjusting the surface tension.

The curing catalyst may be any substance which promotes the reaction between the carboxyl group-containing polyester resin (A) and the epoxy resin (B). Examples thereof include water-soluble quaternary ammonium salts such as choline chloride, nicotinic acid and the like. Examples include amides, metal salts of organic carboxylic acids, and imidazole compounds.

The amount of the curing catalyst used is not particularly limited, but the total solid content of the resins (A) and (B) is 10%.
0.05 to 3 parts by weight is applied to 0 parts by weight.

The aqueous coating composition of the present invention can be applied to various substrates, for example, an untreated or surface-treated metal plate such as an aluminum plate, a steel plate, a tin plate, and an epoxy resin. Metal plate coated with a primer of vinyl or vinyl type, polyethylene terephthalate (PE
T) plates, and those obtained by processing these metal plates and PET into cans and bottles.

As a method for applying the aqueous coating composition of the present invention to a substrate, various known methods such as roll coater coating, spray coating, dipping coating, and electrodeposition coating can be applied.

[0029]

According to the present invention, a composition comprising a specific carboxyl group-containing polyester resin, a water-insoluble epoxy resin and a hydrophobic solvent is dispersed in water,
Aqueous paint composition that can secure sufficient emulsion stability after dispersion in water and can form a coating film with excellent processability and flavor retention even as a polyester resin composition that ensures performance such as processability for the inner surface of cans Is obtained. In particular, by selecting the epoxy resin type, bisphenol A
Can be obtained as a water-based coating composition without elution. The coating composition of the present invention is applicable not only to cans but also to industrial uses such as pre-coated metal.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. “Parts” and “%” mean “parts by weight” and “% by weight”, respectively.

Production of carboxyl group-containing polyester resin
Concrete Production Example 1 stirrer, heater, thermometer, nitrogen gas inlet tube, a stainless steel reaction vessel equipped with a fractionating apparatus and a distillate tank, 8.3 parts of terephthalic acid, 91.3 parts of isophthalic acid, anhydride 9.7 parts of trimellitic acid, 88.9 parts of bishydroxyethyl terephthalate, 26 parts of neopentyl glycol, and dibutyltin dioxide as a reaction catalyst were used as raw materials 100.
Parts, and the temperature was increased while stirring under nitrogen gas introduction. 240 while draining condensation water
After the temperature was raised to ° C, the reaction was maintained at the same temperature. 1 to
When the outflow of water stopped in 2 hours, xylene for accelerating the reaction was added and dehydration condensation was continued, and a carboxyl group-containing polyester resin (A-1) having a number average molecular weight of 3000 and an acid value of 45 was used as the reaction end point. Obtained.

Production Examples 2 to 5 Carboxyl group-containing polyester resins (A-2) to (A-5) were prepared in the same manner as in Production Example 1 except that the raw materials for polyester were changed to the composition shown in Table 1. Obtained. Table 1 also shows the acid value and the number average molecular weight of the polyester resins (A-2) to (A-5).

[0033]

[Table 1]

Preparation of water-based paint Example 1 The polyester resin (A-1) obtained in the above-mentioned production example was mixed with 150
C., and 50 parts of cyclohexanone per 100 parts of the resin were charged into the reactor, and further cooled to 100.degree. When the temperature inside the device reaches 100 ° C,
10 parts of "ECN1299" (Cresol Novolac phenol epoxy resin, manufactured by Asahi Ciba Co., Ltd.) as a curing agent was charged and uniformly dissolved, and then neutralized by adding 5 parts of dimethylethanolamine, followed by stirring of 275 parts of deionized water. Addition and dilution below gave a clear to milky white stable aqueous dispersion with 25% solids. The aqueous dispersion had a good emulsion appearance without settling even after storage at 20 ° C. for one month.

To 100 parts of the aqueous dispersion, 0.25 part of choline chloride as a curing catalyst and 10 parts of isopropyl alcohol for adjusting the surface tension were added with stirring to obtain an aqueous paint.

Examples 2 to 4 and Comparative Examples 1 to 4 In the same manner as in Example 1, except that the composition was changed as shown in Table 2, water-based paints having a solid content of 25% were obtained. . However, the composition of Comparative Example 2 could not be dispersed in water, and a water-based paint could not be obtained.

Performance Test Each of the aqueous paints obtained in Examples and Comparative Examples obtained above was coated on an aluminum plate with a bar coater so as to have a dry film thickness of about 15 μm, and baked at 230 ° C. for 10 minutes. Thus, each test coated plate was obtained. These test coated plates were subjected to the following performance tests. Table 3 shows the results.

(* 1) Coated surface condition: The coated surface of the coated plate was visually observed and evaluated according to the following criteria. ：: The entire coated surface is smooth and no foaming is observed. Δ: Slight unevenness is observed over the entire coated surface and small foaming is observed. X: Slight unevenness is observed over the entire coated surface and large foaming is observed. is (* 2) gel fraction: in the flask, placed coated plate weight _{W 2,} of painted area = 100c of methyl ethyl ketone / coated plate
After adding methyl ethyl ketone so as to obtain c / 100 cm ² and performing extraction under heating and refluxing for 1 hour, the coated plate was taken out, dried at 120 ° C. for 30 minutes, cooled to room temperature, and the weight W ₃ was measured. The weight before tinplate application of paints and W ₁ to coated plate, the gel fraction (%) was calculated by the following equation. Gel fraction _{(%) = {(W 3} -W 1) / (W 2 -W 1)}
× 100 (* 3) Workability: 18 at the bottom of the coated plate with the coating surface facing out
A zero-degree bent portion is provided, and a special goby-fold type Dupont impact tester is used.
The length of the crack in the coating film at the bent portion generated when a kg iron weight was dropped from a height of 50 cm was measured and evaluated according to the following criteria. ：: less than 5 mm △: not less than 5 mm and less than 20 mm ×: not less than 20 mm (* 4) Water resistance: The coated plate was immersed in deionized water at 125 ° C. for 35 minutes in an autoclave and pulled up. Evaluation was made according to the following criteria.

：: No whitening is observed in the coating film Δ: Slight whitening is observed in the coating film ×: Remarkable whitening is observed in the coating film (* 5) Adhesion: Use of a knife for coating the coated plate Then about 1.
Eleven cuts each with a width of 5 mm and a length of 11 were cut into the nicks, and a cellophane adhesive tape with a width of 24 mm was adhered,
The paint film having a strong peeling when strongly peeled was observed and evaluated according to the following criteria.

：: No peeling was observed at all △: Slight peeling was observed ×: Remarkable peeling was observed (* 6) Adhesion after water resistance test: 35 in 125 ° C. deionized water in an autoclave in an autoclave. After immersing for a minute and pulling up, using a knife to make 11 vertical and horizontal cuts in a width of about 1.5 mm using a knife, the cellophane adhesive tape with a width of 24 mm is adhered and strongly peeled off. Was observed and evaluated according to the criteria of the above (* 5).

(* 7) Corrosion resistance: The water-based paints of Examples and Comparative Examples were applied to the inner surface of a steel two-piece can having a content of 250 cc by hot air spraying so as to have a dry film thickness of about 15 μm. Bake for 60 seconds to cure 2
The can body of the piece can was made.

The above two-piece can body was hot-packed with 98% pine juice at 98 ° C. and wound tightly at 37 ° C.
After storing for 6 months, open the can, observe the corrosion state of the inner surface,
Evaluation was made according to the following criteria.

：: No corrosion was observed. Δ: Slight corrosion was observed. ×: Corrosion was noticeable. (* 8) Flavor retention: tap water was prepared using the two-piece can body prepared in (* 6) above. Water 250 treated with activated carbon
The cc was filled and tightened, sterilized at 125 ° C. for 30 minutes, stored at 37 ° C. for 6 months to conduct a flavor test, and evaluated according to the following criteria.

：: No change is observed at all △: Slight change is observed ×: Remarkable change is observed

[0045]

[Table 2]

[0046]

[Table 3]

Continued on the front page F-term (reference) 4J036 AF06 DC41 FA12 FB11 GA11 GA21 GA29 JA01 KA04 4J038 DB072 DB092 DB122 DB132 DD041 DD061 GA06 GA07 JA02 JA05 JA19 JA26 JA33 JA56 JB03 JB09 JB33 JB39 KA06 KA16 LA03 MA14 NA14 PC02 PC08

Claims (3)

[Claims] 1. An esterified product comprising (A) a polyhydric alcohol component containing at least 60 mol% of ethylene glycol and a polybasic acid component containing at least 80 mol% of an aromatic polycarboxylic acid, and having a number average molecular weight of 1 (D) a mixture containing a carboxyl group-containing polyester resin having an acid value of 10 to 170 mgKOH / g, a water-insoluble epoxy resin (B), and a hydrophobic solvent (C) as a main component. A composition for a polyester-based water-based paint, wherein the composition is neutralized with a neutralizing agent and dispersed or dissolved in an aqueous medium. 2. The aqueous coating composition according to claim 1, wherein the epoxy resin (B) is a novolak type epoxy resin. 3. The aqueous coating composition according to claim 1, wherein the hydrophobic solvent (C) is contained in an amount of 1 to 200 parts by weight based on 100 parts by weight of the solid content of the resin.