JPH10259229A - Water-based coating composition and coating film produced from the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition giving a dispersion having excellent storage stability and a coating film having excellent processability, retorting resistance and coating suitability and suitable for the coating of the inner surface of a can for food by mixing an epoxy resin dispersion having large average particle diameter with an epoxy resin dispersion having small particle diameter. SOLUTION: (A) A bisphenol-type phenoxy resin is polymerized with (B) a monomer mixture composed of an unsaturated carboxylic acid monomer and a radically polymerizable unsaturated monomer to produce (C) a carboxylic acid-modified phenoxy resin. The produced phenoxy resin C is dispersed in an aqueous medium in the presence of a basic substance. The objective water- based coating composition is produced by mixing (D) the above water-based resin composition having an average particle diameter of 100-400nm with (E) the above water-based resin composition having an average particle diameter of 600-1,000nm. The weight ratio (solid basis) of the component D to the component E in the composition is preferably 10/90 to 95/5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous coating composition having excellent storage stability and capable of providing a coating excellent in processability, retortability and coatability, and a coating made from the composition.

[0002]

2. Description of the Related Art Steel sheets; steel sheets plated with zinc, tin, etc .;
BACKGROUND ART A coating composition used for coating a metal part made of aluminum or the like for the purpose of rust prevention or the like is becoming more and more water-soluble in terms of air pollution, fire safety, and the like.

[0003] On the other hand, meat, vegetables,
In recent years, fruits and the like have been favored for foods that have good preservability and are easy to cook, and with the spread of easily drinkable beverages and the like, it is widely used to provide them as canned products. It has become Therefore, researches on cans containing foods and beverages and coatings covering the inner surfaces of the cans are currently in progress.

[0004] Coating compositions for forming a coating on the inner surface of a can include:
Excellent coatability is required in order to obtain a smooth coating film without coating film defects such as pinholes, and dispersion stability for withstanding long-term storage is also important. Also, the resulting coating is
In addition to basic properties such as adhesion, corrosion resistance, water resistance, and retort resistance, it does not hinder the appearance of foods from production to use and has little effect on food texture and smell ( It is also important to have flavor resistance.

[0005] Japanese Patent Application Laid-Open No. Hei 6-179821 discloses an aqueous coating composition using a reaction product of an epoxy resin, a phenoxy resin and a carboxyl group-containing acrylic polymer and an aqueous aminoplast. Discloses an aqueous resin composition containing a carboxyl group-containing self-emulsifying vinyl polymer-modified epoxy resin, disclosed in JP-A-8-208.
Japanese Patent Publication No. 802 discloses an aqueous resin composition containing a resin obtained by seed-polymerizing a polymerizable unsaturated monomer in the presence of an aqueous dispersion of a graft polymer obtained by graft-polymerizing a carboxyl-containing unsaturated monomer onto an epoxy-containing resin. Is disclosed.

[0006]

Such an aqueous dispersion of an epoxy resin modified with an acrylic resin has excellent retort properties, but those having a small molecular weight have insufficient workability.
In order to improve the processability, it is better to disperse a large molecular weight epoxy resin in water so that the flexibility of the coating can be expected. Large, and therefore storage stability,
Retort properties and paintability were insufficient.

[0007] The present invention provides a coating which is excellent in storability and also excellent in processability, retortability and coatability, and is particularly capable of providing a coating suitable for use on the inner surface of food or beverage cans. It is an object to provide a coating composition and a coating as described above.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, when an epoxy resin dispersion having a large average particle diameter and a epoxy resin dispersion having a small average particle diameter are mixed, the resulting dispersion is obtained. The inventors have found that the body has excellent storage properties and that the coating obtained therefrom has excellent workability, retort properties and paintability, and thus completed the present invention.

That is, the present invention relates to (1) a carboxylic acid obtained by polymerizing a monomer mixture (B) of an unsaturated carboxylic acid monomer and a radical polymerizable unsaturated monomer on a bisphenol type epoxy resin (A). An aqueous resin composition obtained by dispersing an acid-modified epoxy resin (C) in an aqueous medium in the presence of a basic substance, wherein the aqueous resin composition (a) having an average particle diameter of 100 to 400 nm and an average particle diameter of 600 to 400 nm An aqueous coating composition obtained by mixing an aqueous resin composition (b) having a thickness of 1000 nm; (2) an aqueous resin composition (a) and an aqueous resin composition (b) in which the mixing ratio of the aqueous resin composition (b) is a solid content in the composition; 1 in ratio (weight ratio)
0/90 to 90/10, the aqueous coating composition according to the above (1), (3) a bisphenol-type epoxy resin (A)
Is a high molecular weight bisphenol type epoxy resin (A1) having a number average molecular weight of 10,000 to 50,000 and / or a low molecular weight bisphenol type epoxy resin (A2) having a number average molecular weight of less than 500 to 10,000. The aqueous coating composition according to 1), (4) the weight ratio of the high molecular weight bisphenol type epoxy resin (A1) to the low molecular weight bisphenol type epoxy resin (A2) is 100: 0 to 5
0:50, the aqueous coating composition according to the above (3),
(5) High molecular weight bisphenol type epoxy resin (A1)
Wherein the epoxy equivalent of (3) is 7,500 to 75,000, and (6) the epoxy equivalent of the low molecular weight bisphenol type epoxy resin (A2) is 250.
Aqueous coating composition according to the above (3), wherein
(7) The aqueous coating composition according to the above (1), wherein the monomer mixture (B) has an acid value of 260 to 600, (8) the weight of the bisphenol-type epoxy resin (A) and the monomer mixture (B). The aqueous coating composition according to the above (1), wherein the ratio [(A) / (B)] is 75/25 to 95/5, (9) the aqueous coating composition (1) further containing a phenolic resin and / or an amino resin (D). The aqueous coating composition according to (9), wherein the phenol resin and / or the amino resin (D) is condensed with the carboxylic acid-modified epoxy resin (C), (11) 2 to 4 carbon atoms as diluent
The aqueous coating composition according to the above (1), which comprises a diol of
(12) The above (1) wherein the diol is a diol having 4 carbon atoms.
2) The aqueous coating composition according to any one of the above (1) to (12), which is used for inner surface application of a can end material, and (14) the aqueous coating composition according to the above (1) to (1). 13)
The present invention relates to a film formed by applying the aqueous coating composition according to any one of the above to an object to be coated.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The bisphenol type epoxy resin (A) used in the present invention comprises:
It is divided into two types, a high molecular weight bisphenol type epoxy resin (A1) and a low molecular weight bisphenol type epoxy resin (A2), and these can be used alone or as a mixture.

The high molecular weight bisphenol type epoxy resin (A1) has a number average molecular weight of 10,000 to 50,000. Preferred number average molecular weight is 10,000-3
000, more preferably 12,000 to 20,
000. When the number average molecular weight of the high molecular weight epoxy resin (A1) is in the range of 10,000 to 50,000,
Satisfactory storage stability and processability are obtained.

The epoxy equivalent of the high molecular weight epoxy resin (A1) (the value obtained by dividing the average molecular weight by the number of epoxy groups per molecule: g / equiv.) Is preferably 7.5.
00 to 75,000, more preferably 15,000 to
50,000, most preferably 20,000 to 40,0
00. Epoxy equivalent of 7,500 to 75,000
If so, satisfactory workability and retortability can be obtained.

Examples of the high molecular weight epoxy resin (A1) include bisphenol A (4,4'-dihydroxydiphenyl-2,2-propane) and bisphenol F (4
4′-dihydroxydiphenylmethane) and condensates obtained by condensing epihalohydrin, β-methylepihalohydrin, etc. with these halogen-substituted products. As such a high molecular weight epoxy resin (A1),
Commercially available ones can also be used. For example, Epicoat 1255-HX-30 (manufactured by Yuka Shell Epoxy), PKHH, PKHJ, PKHC (manufactured by Phenoxy Associates), phenotote YP-50S, phenothote YP-50, ZX-1356, ZX-1395, Z
X-1449-2, ZX-1449-4 (manufactured by Toto Kasei) and the like. These may be used alone or in combination of two or more.

The low molecular weight bisphenol type epoxy resin (A2) has a number average molecular weight of less than 500 to 10,000, preferably less than 5,000 to 10,000.
The number average molecular weight of the low molecular weight epoxy resin (A2) is 500
When it is less than 10,000, satisfactory workability and retortability can be obtained.

The epoxy equivalent of the low molecular weight epoxy resin (A2) is preferably from 250 to 9,000, more preferably from 2,000 to 7,000. When the epoxy equivalent is 250 to 9,000, satisfactory processability and retortability can be obtained.

As the low molecular weight epoxy resin (A2), for example, bisphenol A (4,4'-dihydroxydiphenyl-2,2) is used as in the case of the high molecular weight epoxy resin (A1).
-Propane), bisphenol F (4,4'-dihydroxydiphenylmethane), and condensates obtained by condensing epihalohydrin, β-methylepihalohydrin, etc. with these halogen-substituted products. As such a low molecular weight epoxy resin (A2), a commercially available resin can also be used. For example, Epicoat 100
1, 1005, 1007, 1010 (manufactured by Yuka Shell Epoxy), Epotote YD-012, YD-014, Y
D-017, YD-020H, ZX-1373-8 (manufactured by Toto Kasei) and the like. These may be used alone or in combination of two or more.

The mixing ratio (weight ratio) between the high molecular weight epoxy resin (A1) and the low molecular weight epoxy resin (A2) is as follows:
(A1) / (A2) = 100/0 to 50/50 is preferable, and 100/0 to 80/20 is more preferable.
When (A1) / (A2) = 100/0 to 50/50, workability is excellent.

The unsaturated carboxylic acid monomer which is an essential component of the monomer mixture (B) includes, for example, monocarboxylic acid or dicarboxylic acid such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, and ethyl maleate. And monoesters of dicarboxylic acids such as butyl maleate, ethyl itaconate and butyl itaconate. Among them, acrylic acid and methacrylic acid are preferred.

As the radical polymerizable unsaturated monomer, a vinyl monomer can be used without any particular limitation. For example, α, β-ethylenically unsaturated aliphatic carboxylic acids such as ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and 2-ethylhexyl methacrylate Acid alkyl ester monomer; acrylic acid 2
Hydroxyl groups such as -hydroxyethyl, 4-hydroxybutyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, and a reaction product of 2-hydroxyethyl methacrylate with ε-caprolactone Α, β with
An alkyl ester monomer of an ethylenically unsaturated aliphatic carboxylic acid; an amide monomer such as acrylamide, methacrylamide, N-methylol acrylamide, methoxybutyl acrylamide, diacetone acrylamide; an α such as glycidyl acrylate or glycidyl methacrylate; , Β
A glycidyl ester monomer of an ethylenically unsaturated aliphatic carboxylic acid; a vinyl ester monomer of a saturated aliphatic carboxylic acid such as vinyl acetate or vinyl propionate;
Styrene-based monomers such as α-methylstyrene and vinyltoluene are exemplified.

The acid value of the monomer mixture (B) is from 260 to 6
00 is preferable, and 480 to 580 is more preferable. When the acid value is from 260 to 600, water dispersibility and storage stability are improved.

The carboxylic acid-modified epoxy resin (C) is, for example, prepared by dissolving a bisphenol type epoxy resin (A) in an organic solvent in a solution of an unsaturated carboxylic acid monomer and a radical polymerizable unsaturated monomer. The monomer mixture (B),
In the presence of a polymerization initiator at a temperature of 40 to 150 ° C.,
It can be obtained by reacting for 8 hours.

The mixing ratio (A) / (B) of the bisphenol type epoxy resin (A) and the monomer mixture (B) is preferably 75/25 to 95/5 (weight ratio), more preferably 85/25. 15 to 90/10. (A) / (B) is 7
When the ratio is 5/25 to 95/5, satisfactory workability, corrosion resistance, dispersion stability, and storage stability can be obtained.

The organic solvent used for the polymerization is not particularly limited, butanol, isopropanol, ethoxyethanol, ethoxypropanol, methoxypropanol, butoxyethanol, diethylene glycol monobutyl, ethylene glycol, 1,2-butanediol,
Alcohols such as 1,4-butanediol, esters such as butyl acetate and ethyl acetate, hydrocarbons such as toluene and xylene, ethers such as dibutyl ether and ethylene glycol diethyl, ketones such as methyl ethyl ketone and isobutyl methyl ketone And amides such as N-methylpyrrolidone.

The polymerization initiator is not particularly limited either, and organic peroxides such as benzoyl peroxide, di-t-butyl peroxide and t-butyl perbenzoate, azobiscyanovaleric acid,
Organic azo compounds such as azobisisobutyronitrile and the like can be used. The amount of the polymerization initiator depends on the amount of the monomer mixture (B) 10
1 to 15 parts by weight per 0 parts by weight is preferred.

The aqueous coating composition containing the carboxylic acid-modified epoxy resin (C) further comprises a phenolic resin and / or
Alternatively, an amino resin (D) may be contained.

Phenolic resin and amino resin (D)
Has a number average molecular weight of preferably from 100 to 5,000. When the number average molecular weight is within this range, retort resistance and dispersibility are improved.

As the phenolic resin (D), for example,
Resol type phenolic resin (phenol, carbon number 1-1)
Reaction products obtained by reacting phenol, bisphenol A, bisphenol F, or the like substituted with an alkyl group 2 with formaldehyde with an alkali catalyst), novolak-type phenol resin (phenol, having 1 to 12 carbon atoms)
Reaction products obtained by reacting phenol, bisphenol A, bisphenol F, or the like substituted with an alkyl group with formaldehyde with an acid catalyst). As such a phenolic resin (D), a commercially available resin can also be used. For example, Shaunol BKM-2620, CKM-908, CKS-39
4, CKS-380, ARL-080 (manufactured by Showa Polymer Co., Ltd.) and the like.

Examples of the amino resin (D) include dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, hexamethylolmelamine, dimethylolbenzoguanamine,
Trimethylol benzoguanamine, tetramethylol benzoguanamine, alkyl ethers thereof, urea-formaldehyde condensate, urea-melamine cocondensate and the like can be mentioned. Further, as commercially available, for example, Cymel 303, Cymel 235, Cymel 25
4, Cymel 325, Cymel 1128, Cymel 11
56 (manufactured by American Cyanamid), My Court 10
2, My Court 105, My Court 506 (manufactured by American Cyanamid), U-Van 20N, U-Van 20S
B, U-Van 128 (manufactured by Mitsui Toatsu Chemicals), Sumimar M-50W, Sumimar M-30W (manufactured by Sumitomo Chemical Co., Ltd.) and the like.

The amount of the resin (D) is preferably [resin (D) / carboxylic acid-modified epoxy resin (C)] × 100, less than 15% by weight, more preferably 0.5 to 10% by weight.

The phenolic resin and / or the amino resin (D) may be condensed with the carboxylic acid-modified epoxy resin (C). Such a condensate is, for example, a phenolic resin and / or a carboxylic acid-modified epoxy resin (C).
Alternatively, uniformly mix the amino resin (D),
It is obtained by reacting at 200 ° C., preferably 100 to 150 ° C., for 30 minutes to 5 hours, preferably 1 to 5 hours.

The addition (condensation) of the phenolic resin and / or the amino resin (D) to the carboxylic acid-modified epoxy resin (C) is carried out before the carboxylic acid-modified epoxy resin (C) is made aqueous (water-dispersed) as described below. But you can do it later.

The dispersion is carried out using a basic substance. That is, the aqueous dispersion is dissolved in an aqueous medium in the presence of a basic substance necessary to neutralize 30 to 125 mol%, preferably 50 to 100 mol% of the carboxyl groups of the monomer mixture (B). Obtained by dispersing.

As the basic substance to be used, an aliphatic amine compound having 6 or less carbon atoms is preferable. Specifically, ammonia, monomethylamine, dimethylamine, trimethylamine, triethylamine, diisopropylamine, tributylamine, triethylamine, monoethanolamine, diethanolamine, cyclohexylamine, dimethylethanolamine, methylethanolamine, morpholine, N-methylmorpholine, piperidine Etc. first
Examples thereof include amine compounds such as a secondary amine, a secondary amine and a tertiary amine, and an amine compound having a hydroxyl group such as dimethylethanolamine is particularly preferable.

The method of dispersion is not particularly limited.
A method of gradually adding an aqueous medium in which an appropriate amount of a basic substance is dissolved to a carboxylic acid-modified epoxy resin (C), a method of gradually adding the resin (C) to an aqueous medium in which an appropriate amount of a basic substance is dissolved, There is a method of mixing an appropriate amount of a basic substance into the resin (C), and then gradually adding an aqueous medium. Dispersion can be performed by a commonly used stirrer. The temperature at the time of dispersion is not particularly limited, but is preferably 40 to 1
00 ° C, more preferably 60 to 90 ° C.

The average particle size of the aqueous dispersion can be controlled by selecting one of the dispersion methods described above. For example, the above methods tend to increase the average particle size.
It can also be controlled by changing the acid value of the carboxylic acid-modified epoxy resin (C) and the amount of carboxylic acid modification. For example, reducing the acid value of the resin or the composition increases the particle size.

The aqueous resin composition (a) having an average particle diameter of 100 to 400 nm is a carboxylic acid-modified epoxy resin (C)
When the amount of carboxylic acid modification of the compound is increased, the production becomes easier. For example, when the bisphenol type epoxy resin (A) / the monomer mixture (B) is reacted at a weight ratio of 90/10 to 95/5 to obtain the carboxylic acid-modified epoxy resin (C), the monomer mixture is used. When the acid value of (B) is set to 450 to 600, the average particle size of the composition tends to be in the range of 100 to 400 nm. Also, (A) / (B) is 75 / 25-89.
When the reaction is carried out at / 11, the acid value of the monomer mixture (B) is set to 300 to 450, so that it is easy to enter the above range. In this case, the acid value of the carboxylic acid-modified epoxy resin (C) is preferably adjusted to 40 to 65.

The aqueous resin composition (b) having an average diameter of from 600 to 1000 nm can be easily produced by reducing the amount of carboxylic acid-modified epoxy resin (C) modified with carboxylic acid. For example, bisphenol type epoxy resin (A) /
When the monomer mixture (B) is reacted at a weight ratio of 90/10 to 95/5 to obtain a carboxylic acid-modified epoxy resin (C), the acid value of the monomer mixture (B) is set to 300 to 400.
The average particle size of the composition is 600 to 1000 n
m. (A) / (B) is 75/2
When the reaction is carried out at 5 to 89/11, the acid value of the monomer mixture (B) is set to 200 to 300, so that it is easy to enter the above range. In this case, the acid value of the carboxylic acid-modified epoxy resin (C) is preferably adjusted to 25 to 39.

The solid content in the aqueous resin composition (a) having an average particle diameter of 100 to 400 nm is not particularly limited.
Preferably 15 to 35% by weight, more preferably 25 to 35% by weight.
35% by weight. In addition, the average particle diameter is 600 to 100
The solid content in the aqueous resin composition (b) having a thickness of 0 nm is not particularly limited, but is preferably 15 to 40% by weight, and more preferably 25 to 35% by weight.

The aqueous coating composition of the present invention comprises an aqueous resin composition (a) having an average particle diameter of 100 to 400 nm and an aqueous resin composition (b) having an average particle diameter of 600 to 1000 nm. Are obtained by mixing

The mixing ratio (weight ratio) of the aqueous resin composition (a) having an average particle diameter of 100 to 400 nm and the aqueous resin composition (b) having an average particle diameter of 600 to 1000 nm is determined by the solid content ratio in the composition. [(A) / (b)], 10/90 to 90
/ 10 is preferable, and 50/50 to 80/20 is more preferable. When the mixing ratio is in the range of 10/90 to 90/10, excellent workability, retortability, and paintability can be obtained.

The aqueous coating composition of the present invention has 2 to 4 carbon atoms.
May be added as a diluent. Specific examples of the diluent include, for example, ethylene glycol, diethylene glycol, propylene glycol, butanediol, and the like. Above all, butanediol is preferred from the viewpoint of workability with less occurrence of armpits. The time of addition of the diluent is not particularly limited, and may be added to the aqueous coating composition, may be added to the obtained resin before being dispersed in water, or may be added to the aqueous medium. The addition amount is not particularly limited, either, but it is preferable to add the organic solvent content of the aqueous coating composition so as to be 20% by weight or less.

The aqueous coating composition may be desolvated under reduced pressure and normal pressure in order to remove the organic solvent in the composition. The final aqueous solvent content of the resulting aqueous coating composition is 20
% By weight or less is preferred.

The acid value of the aqueous coating composition is preferably from 25 to 100, more preferably from 30 to 65. When the acid value is 25 to 100, particularly excellent dispersibility, storage stability, and retortability can be obtained.

The solid content in the aqueous coating composition of the present invention is not particularly limited, but is preferably 25 to 40% by weight, more preferably 28 to 35% by weight.

If necessary, a catalyst such as an inorganic acid such as hydrochloric acid or phosphoric acid, or an organic acid such as p-toluenesulfonic acid may be added to the aqueous coating composition of the present invention. The addition amount of the catalyst is preferably 1 part by weight or less based on 100 parts by weight of the solid content of the aqueous coating composition.

The aqueous coating composition may further contain a pigment, a rust preventive, other water-soluble resins, additives, etc., depending on the purpose, and used as a rust preventive primer, a rust preventive paint, an aqueous printing ink, etc. can do.

The aqueous coating composition of the present invention can be applied to a substrate to form a coating. The substrate to be applied is not particularly limited, and examples thereof include an aluminum plate; a steel plate; zinc;
Plated steel sheet plated with one or more metals such as chromium, tin, nickel, and aluminum; Steel sheet whose surface is chemically or electrically treated with chromic acid, phosphoric acid, zinc phosphate, etc .; Paper, wood, etc. Can be.

The method of applying the aqueous coating composition to the object to be coated is not particularly limited, and examples thereof include known methods such as spray coating, roll coater coating, electrodeposition coating, dip coating, and brush coating.

As the curing conditions for the coating, drying at room temperature is possible, but forced drying at a temperature in the range of 80 to 350 ° C. for 10 seconds to 30 minutes is preferred. The thickness of the coating is preferably 5 to 30 μm. A coating film formed by applying the aqueous resin composition of the present invention to an object to be coated in this way is also one of the present invention.

When the aqueous coating composition is used for coating the inner surface of a can, it is usually preferable to apply the composition using a roll coater. Food and beverage cans usually include a three-piece can consisting of a lid part, a cylindrical peripheral part, and a bottom part, and a two-piece can consisting of a lid part and other parts. When applying the aqueous resin composition, the lid portion and the cylindrical peripheral portion of the three-piece can can be applied by a roll coater. In the case of coating the cylindrical peripheral portion, bottom portion, etc. of a two-piece can, spray coating is preferred.

The aqueous resin composition of the present invention can be suitably applied particularly to so-called end materials such as lids of cans. However, it does not apply only to the inner surface of the can,
For example, it can be applied to building materials, home electric appliances, automobile parts, and the like.

[0052]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 (Production of a composition containing small particle size particles) 255 weight parts of Epicoat EP-1256 [Phenoxy resin (high molecular weight bisphenol type epoxy resin, hereinafter the same), manufactured by Yuka Shell Epoxy Co., Ltd.) was added to a reaction vessel. Parts, 77 parts by weight of diethylene glycol monobutyl ether, and 305 parts by weight of methoxypropanol, and the temperature was gradually increased while stirring, and 110 ° C.
The phenoxy resin was dissolved in 2 hours. Methacrylic acid 21
Parts by weight, 12 parts by weight of styrene, 12 parts of ethyl acrylate
1 part by weight of a monomer solution consisting of 4 parts by weight of benzoyl peroxide and 15 parts by weight of toluene in a phenoxy resin solution.
0.5 to 110 ° C., dropwise for 2 hours, and
Stirring was continued at 0 ° C. for 3 hours. Shownor C
9 parts by weight of KM-908 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and reacted at 120 ° C. for 3 hours to pre-condense the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 22 parts by weight of dimethylethanolamine and 2358 parts by weight of deionized water was cooled to 70 ° C.
The mixture was added dropwise to the reaction solution with stirring at 2 ° C. for 2 hours to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the non-volatile
%, A composition (I-1) containing small-diameter particles having an average particle diameter of 350 nm was obtained.

(Production of Composition Containing Large Particles) In a reaction vessel, 270 parts by weight of phenotote YP-50S (Phenoxy resin, manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 30
5 parts by weight were charged, and the temperature was gradually increased while stirring.
The phenoxy resin was dissolved at 2 ° C. for 2 hours. 18 parts by weight of methacrylic acid, 6 parts by weight of styrene, 6 parts of ethyl acrylate
1 part by weight of a monomer solution consisting of 4 parts by weight of benzoyl peroxide and 15 parts by weight of toluene in a phenoxy resin solution.
0.5 to 110 ° C., dropwise for 2 hours, and
Stirring was continued at 0 ° C. for 3 hours. Shownor C
18 parts by weight of KS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution,
The reaction was allowed to proceed for a period of time to pre-condense the phenol resin. The reaction solution was cooled to 70 ° C and dimethylethanolamine 19
80 parts by weight of an aqueous solution consisting of 470 parts by weight of deionized water
The mixture was added dropwise to the reaction solution at 1 ° C. with stirring for 1 hour to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the non-volatile
%, A composition (II-1) containing large-diameter particles having an average particle diameter of 708 nm was obtained.

(Production of Aqueous Coating Composition) 600 parts by weight of the obtained composition (I-1) and 400 parts by weight of the composition (II-1) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. In Tables 1 and 2, MAA is methacrylic acid, S
T is styrene, EA is ethyl acrylate, BDG is diethylene glycol monobutyl ether, MP is methoxypropanol, and BD is 1,2-butanediol. The aqueous coating composition was diluted with 1,2-butanediol (10 parts by weight based on 100 parts by weight of solids in the composition), and dried on a 0.3 mm-thick aluminum plate.
Paint with a bar coater to a thickness of 3 μm
Bake for 0 seconds. Length: 5 cm, width: 1 from the baked film
A 0 cm test piece was cut. The storage stability of the aqueous coating composition and the retort resistance, workability, and corrosion resistance of the baked film were evaluated by the following test methods. Table 3 shows the results.

Storage Stability of Aqueous Coating Composition Diluted with 10 times the volume of deionized water,
After 30 days, the presence or absence of sedimentation was examined. ：: No sedimentation after 30 days ○: No sedimentation after 20 days, sedimentation after 30 days △: No sedimentation after 10 days, sedimentation after 20 days ×: Sedimentation after 10 days

A retort-resistant autoclave was charged with deionized water, and the test piece was heated at 125 ° C.
For 30 minutes, and the degree of whitening of the film was visually determined. ◎: no whitening ○: slight whitening △: slight whitening ×: considerable whitening

[0058] As shown in workability Figure 1, the coating 3 of the test piece 1 to the outside, the test piece 1 as thick as in the aluminum plate 2 so as to sandwich one specimen 1 (0.3 mm) Was bent, tightened with a bias, and the degree of cracking of the processed portion 4 was determined using a 50-fold loupe. ◎: No cracks ○: Slight cracks △: Slight cracks ×: Significant cracks

Corrosion Resistance A test piece whose back surface was sealed with a polyester tape was immersed in boiling 3% saline to determine the degree of corrosion of the coated surface. ：: No corrosion ○: Slightly corroded △: Slightly corroded ×: Significantly corroded

Average Particle Diameter The average particle diameter was measured by a laser scattering method using ELS-800 manufactured by Otsuka Electronics Co., Ltd.

The paintability of the baked film was observed with a 15X magnifier to determine the presence or absence of pinholes. ◎: No pinhole ○: Slight pinhole △: Partly pinhole ×: Pinhole on entire surface

Example 2 (Production of a composition containing small-diameter particles) In a reaction vessel, 270 parts by weight of phenotote YP-50S (Phenoxy resin manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 305 were used. The weight was gradually increased while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. Methacrylic acid 21 parts by weight,
A monomer solution consisting of 6 parts by weight of styrene, 3 parts by weight of ethyl acrylate, 3 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was added to a phenoxy resin solution at 105 to 110 parts.
C., the mixture was added dropwise at 2 hours, and stirring was continued at 105 to 110 ° C. for 3 hours. In addition, Shaunor CKS-90
8 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) 18
A part by weight was added to the above reaction solution and reacted at 120 ° C. for 3 hours to pre-condense the phenol resin. Reaction solution 70
After cooling to ℃, an aqueous solution comprising 22 parts by weight of dimethylethanolamine and 2352 parts by weight of deionized water was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the composition (I-2) containing small particles having a nonvolatile content of 35% and an average particle diameter of 212 nm was obtained.
I got

(Production of Composition Containing Large Particles) In a reaction vessel, 270 parts by weight of phenotote YP-50S (Phenoxy resin manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 30
5 parts by weight were charged, and the temperature was gradually increased while stirring.
The phenoxy resin was dissolved at 2 ° C. for 2 hours. Methacrylic acid 15 parts by weight, styrene 6 parts by weight, ethyl acrylate 9
1 part by weight of a monomer solution consisting of 4 parts by weight of benzoyl peroxide and 15 parts by weight of toluene in a phenoxy resin solution.
0.5 to 110 ° C., dropwise for 2 hours, and
Stirring was continued at 0 ° C. for 3 hours. Shownor C
6 parts by weight of KS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and reacted at 120 ° C. for 3 hours to pre-condense the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 16 parts by weight of dimethylethanolamine and 489 parts by weight of deionized water was added to 80 parts by weight.
The mixture was added dropwise to the reaction solution at 1 ° C. with stirring for 1 hour to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the non-volatile
%, A composition (II-2) containing large-diameter particles having an average particle diameter of 805 nm was obtained.

(Production of Aqueous Coating Composition) 800 parts by weight of the obtained composition (I-2) and 200 parts by weight of the composition (II-2) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Example 3 (Production of Composition Containing Small Particle Size) ZX-1 was placed in a reaction vessel.
449-4 (Phenoxy resin, manufactured by Toto Kasei Co., Ltd.)
Parts by weight, diethylene glycol monobutyl ether 77
Parts by weight, 305 parts by weight of methoxypropanol,
The temperature was gradually increased with stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. A monomer solution consisting of 15 parts by weight of methacrylic acid, 1.5 parts by weight of styrene, 1.5 parts by weight of ethyl acrylate, 2 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was added to a solution of 105 to 11 parts in a phenoxy resin solution.
The mixture was added dropwise at 0 ° C for 2 hours, and the stirring was further continued at 105 to 110 ° C for 3 hours. The reaction solution was cooled to 70 ° C., and 16 parts by weight of dimethylethanolamine and 2285 of deionized water were used.
An aqueous solution consisting of parts by weight was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure, the nonvolatile content was 35%, and the average particle size was 280 nm.
A composition (I-3) containing the small particles of the formula (I-3) was obtained.

(Production of Composition Containing Large Particles) 240 parts by weight of phenotote YP-50S (Phenoxy resin manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 30 were placed in a reaction vessel.
5 parts by weight were charged, and the temperature was gradually increased while stirring.
The phenoxy resin was dissolved at 2 ° C. for 2 hours. Methacrylic acid 24 parts by weight, styrene 24 parts by weight, ethyl acrylate 12 parts by weight, benzoyl peroxide 6 parts by weight, toluene 15
A monomer solution consisting of parts by weight was added dropwise to the solution of the phenoxy resin at 105 to 110 ° C. over 2 hours,
Stirring was continued at 110 ° C. for 3 hours. Further, 12 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution,
For 3 hours to pre-condense the phenol resin.
The reaction solution was cooled to 70 ° C., and an aqueous solution comprising 25 parts by weight of dimethylethanolamine and 484 parts by weight of deionized water was added dropwise to the reaction solution at 80 ° C. for 1 hour with stirring to disperse. Thereafter, the solvent and water were removed under reduced pressure to obtain a composition (II-3) containing 35% non-volatile content and large-diameter particles having an average particle diameter of 708 nm.

(Production of Aqueous Coating Composition) 800 parts by weight of the obtained composition (I-3) and 200 parts by weight of the composition (II-3) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Example 4 (Production of Composition Containing Small Particle Size) ZX-1 was placed in a reaction vessel.
449-4 (Phenoxy resin, manufactured by Toto Kasei) was added to 135
Parts by weight, 135 parts by weight of phenotote YP-50S (manufactured by Toto Kasei Co., Ltd., phenoxy resin), 38.5 parts by weight of diethylene glycol monobutyl ether, 38.5 parts by weight of 1,2-butanediol, and 305 parts by weight of methoxypropanol were charged. , The temperature was gradually increased while stirring, 110 ° C,
The phenoxy resin was dissolved in 2 hours. Methacrylic acid 24
A monomer solution consisting of 3 parts by weight of styrene, 3 parts by weight of styrene, 3 parts by weight of ethyl acrylate, 3 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was added to a solution of 105 parts of phenoxy resin.
~ 110 ° C, dropped in 2 hours, further 105 ~ 110 ° C
For 3 hours. Shownor CKS
18 parts by weight of -394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 25 parts by weight of dimethylethanolamine and 2347 parts by weight of deionized water was added to 70 parts by weight.
The mixture was added dropwise to the reaction solution with stirring at 2 ° C. for 2 hours to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the non-volatile
%, A composition (I-4) containing small-diameter particles having an average particle diameter of 203 nm was obtained.

(Production of Composition Containing Large Particles) In a reaction vessel, 240 parts by weight of phenotote YP-50S (Phenoxy resin manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 30
5 parts by weight were charged, and the temperature was gradually increased while stirring.
The phenoxy resin was dissolved at 2 ° C. for 2 hours. Methacrylic acid 24 parts by weight, styrene 24 parts by weight, ethyl acrylate 12 parts by weight, benzoyl peroxide 6 parts by weight, toluene 15
A monomer solution consisting of parts by weight was added dropwise to the solution of the phenoxy resin at 105 to 110 ° C. over 2 hours,
Stirring was continued at 110 ° C. for 3 hours. Furthermore, 7 parts by weight of Shonor ARL-080 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C. and dimethylethanolamine 2
An aqueous solution consisting of 5 parts by weight and 489 parts by weight of deionized water
The mixture was added dropwise to the reaction solution with stirring at 0 ° C. for 1 hour to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the non-volatile
A composition (II-4) containing 5%, large-diameter particles having an average particle diameter of 708 nm was obtained.

(Production of Aqueous Coating Composition) 500 parts by weight of the obtained composition (I-4) and 500 parts by weight of the composition (II-4) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Example 5 (Production of Composition Containing Small Particle Size) ZX-1 was placed in a reaction vessel.
449-4 (manufactured by Toto Kasei Co., Ltd., phenoxy resin)
Parts by weight, diethylene glycol monobutyl ether 3
8.5 parts by weight, 38.5 parts by weight of 1,2-butanediol and 305 parts by weight of methoxypropanol were charged, and the temperature was gradually increased while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. Methacrylic acid 21 parts by weight, styrene 6
A monomer solution consisting of 3 parts by weight of ethyl acrylate, 3 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was added dropwise to the solution of the phenoxy resin at 105 to 110 ° C. for 2 hours, and further at 105 to 110 ° C. for 3 hours. The stirring was continued. Furthermore, 9 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C., and 22 parts by weight of dimethylethanolamine and 229 of deionized water were used.
An aqueous solution consisting of 9 parts by weight was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure to obtain a nonvolatile content of 35% and an average particle size of 236 n.
A composition (I-5) containing particles having a small particle size of m was obtained.

(Production of Composition Containing Large Particles) 255 parts by weight of Epicoat EP1010 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy resin (low molecular weight bisphenol type epoxy resin, the same applies hereinafter)) in a reaction vessel, diethylene glycol monobutyl ether 77 parts by weight and 305 parts by weight of methoxypropanol were charged, and the temperature was gradually increased while stirring.
The epoxy resin was dissolved at 110 ° C. for 2 hours. A monomer solution consisting of 18 parts by weight of methacrylic acid, 15 parts by weight of styrene, 12 parts by weight of ethyl acrylate, 5 parts by weight of benzoyl peroxide and 15 parts by weight of toluene was dropped into the epoxy resin solution at 105 to 110 ° C. for 2 hours, Further 105
Stirring was continued at １１０110 ° C. for 3 hours. Furthermore, 7 parts by weight of Shonor ARL-080 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution,
For 3 hours to pre-condense the phenol resin.
The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 18 parts by weight of dimethylethanolamine and 497 parts by weight of deionized water was added dropwise to the reaction solution at 80 ° C. for 1 hour while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure to obtain a composition (II-5) containing 35% non-volatile content and large-diameter particles having an average particle diameter of 805 nm. (Production of aqueous coating composition) Composition (I-5) 9 obtained
00 parts by weight and 100 parts by weight of the composition (II-5) were mixed to obtain an aqueous coating composition. A composition comprising small sized particles,
Tables 1 and 2 show the raw materials of the composition containing the large-diameter particles, the amount used and the average particle diameter, and the mixing ratio of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance of the baked film, the workability,
The corrosion resistance and paintability were evaluated. Table 3 shows the results.

Example 6 (Production of Composition Containing Small Particles) ZX-1 was placed in a reaction vessel.
449-4 (Phenoxy resin, manufactured by Toto Kasei Co., Ltd.)
Parts by weight, diethylene glycol monobutyl ether 3
8.5 parts by weight, 38.5 parts by weight of 1,2-butanediol and 305 parts by weight of methoxypropanol were charged, and the temperature was gradually increased while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. 24 parts by weight of methacrylic acid, styrene 1
A monomer solution consisting of 2 parts by weight, 9 parts by weight of ethyl acrylate, 5 parts by weight of benzoyl peroxide and 15 parts by weight of toluene was added dropwise to the solution of the phenoxy resin at 105 to 110 ° C. for 2 hours. Stirring was continued for hours. Further, 6 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. Cool the reaction solution to 70 ° C.
25 parts by weight of dimethylethanolamine, deionized water 22
An aqueous solution consisting of 97 parts by weight was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to effect dispersion. Thereafter, the solvent and water were removed under reduced pressure to obtain a nonvolatile content of 35% and an average particle size of 183.
Thus, a composition (I-6) containing particles having a small particle diameter of nm was obtained.

(Production of Composition Containing Large Particles) A reaction vessel was charged with 255 parts by weight of ZX-1449-4 (Phenoxy resin, manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and 305 parts by weight of methoxypropanol. Charge, gradually raise the temperature while stirring, 110 ° C, 2
The phenoxy resin dissolved in time. A monomer solution consisting of 18 parts by weight of methacrylic acid, 12 parts by weight of styrene, 15 parts by weight of ethyl acrylate, 5 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was added to a solution of phenoxy resin in 10 parts.
5 to 110 ° C., dropped in 2 hours, and further 105 to 110 ° C.
Stirring was continued for 3 hours at ° C. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 18 parts by weight of dimethylethanolamine and 480 parts by weight of deionized water was added dropwise to the reaction solution at 80 ° C. for 1 hour while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the nonvolatile content was 35% and the average particle size was 88.
A composition (II-6) containing large-diameter particles of 6 nm was obtained.

(Production of Aqueous Coating Composition) 500 parts by weight of the obtained composition (I-6) and 500 parts by weight of the composition (II-6) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Example 7 (Production of Composition Containing Small Particles) In a reaction vessel, 270 parts by weight of phenotote YP-50S (Phenoxy resin, manufactured by Toto Kasei Co., Ltd.), 38.5 parts by weight of diethylene glycol monobutyl ether, 1 part by weight , 2-butanediol (38.5 parts by weight) and methoxypropanol (305 parts by weight) were charged, the temperature was gradually increased while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. A monomer solution composed of 21 parts by weight of methacrylic acid, 6 parts by weight of styrene, 3 parts by weight of ethyl acrylate, 3 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was dropped into the solution of the phenoxy resin at 105 to 110 ° C. for 2 hours. Further, stirring was continued at 105 to 110 ° C. for 3 hours. Furthermore, 18 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 22 parts by weight of dimethylethanolamine and 2290 parts by weight of deionized water was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the nonvolatile content was 35%, and the average particle size was 1
A composition (I-7) containing small particle diameters of 76 nm was obtained.

(Production of Composition Containing Large Particles) In a reaction vessel, 255 parts by weight of Epicoat EP-1005F (epoxy resin manufactured by Yuka Shell Epoxy), 77 parts by weight of diethylene glycol monobutyl ether, and 305 parts by weight of methoxypropanol Was gradually heated while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. A monomer solution consisting of 18 parts by weight of methacrylic acid, 15 parts by weight of styrene, 12 parts by weight of ethyl acrylate, 5 parts by weight of benzoyl peroxide and 15 parts by weight of toluene was dropped into the epoxy resin solution at 105 to 110 ° C. for 2 hours, Further, stirring was continued at 105 to 110 ° C. for 3 hours. Furthermore, 12 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the reaction solution,
The reaction was carried out at 120 ° C. for 3 hours to pre-condense the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 18 parts by weight of dimethylethanolamine and 492 parts by weight of deionized water was added dropwise to the reaction solution at 80 ° C. for 1 hour while stirring to carry out dispersion. Then, the solvent and water were removed under reduced pressure,
A composition (II-7) containing 35% non-volatile components and large-diameter particles having an average particle diameter of 923 nm was obtained.

(Production of Aqueous Coating Composition) 950 parts by weight of the obtained composition (I-7) and 50 parts by weight of the composition (II-7) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance of the baked film,
Workability, corrosion resistance and paintability were evaluated. Table 3 shows the results.

Example 8 (Production of a composition containing small particle size particles) 255 parts by weight of Epicoat EP-1256 (Phenoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, methoxypropanol 305
Parts by weight, and the temperature was gradually increased while stirring.
The phenoxy resin was dissolved at 2 ° C. for 2 hours. Methacrylic acid 21 parts by weight, styrene 12 parts by weight, ethyl acrylate 12 parts by weight, benzoyl peroxide 4 parts by weight, toluene 15
A monomer solution consisting of parts by weight was added dropwise to the solution of the phenoxy resin at 105 to 110 ° C. over 2 hours,
Stirring was continued at 110 ° C. for 3 hours. Furthermore, Cymel 2
35 (American Cyanamid, melamine resin) 4
Parts by weight were added to the above reaction solution and reacted at 80 ° C. for 3 hours to pre-condense the amino resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 22 parts by weight of dimethylethanolamine and 2358 parts by weight of deionized water was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. afterwards,
The solvent and water were removed under reduced pressure to obtain a composition (I-8) containing non-volatile components 35% and small-diameter particles having an average particle diameter of 311 nm.

(Production of Composition Containing Large Particles) In a reaction vessel, 270 parts by weight of phenotote YP-50S (Phenoxy resin, manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 30
5 parts by weight were charged, and the temperature was gradually increased while stirring.
The phenoxy resin was dissolved at 2 ° C. for 2 hours. 18 parts by weight of methacrylic acid, 6 parts by weight of styrene, 6 parts of ethyl acrylate
1 part by weight of a monomer solution consisting of 4 parts by weight of benzoyl peroxide and 15 parts by weight of toluene in a phenoxy resin solution.
0.5 to 110 ° C., dropwise for 2 hours, and
Stirring was continued at 0 ° C. for 3 hours. In addition, Cymel 235
9 parts by weight of a melamine resin (manufactured by American Cyanamid Co.) was added to the above reaction solution and reacted at 80 ° C. for 3 hours to pre-condense the amino resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 19 parts by weight of dimethylethanolamine and 470 parts by weight of deionized water was added dropwise to the reaction solution at 80 ° C. for 1 hour with stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure to obtain a nonvolatile content of 35% and an average particle size of 68.
A composition (II-8) containing 9 nm large-diameter particles was obtained.

(Production of Aqueous Coating Composition) 600 parts by weight of the obtained composition (I-8) and 400 parts by weight of the composition (II-8) were mixed to obtain an aqueous coating composition. Tables 1 and 2 show the raw materials of the composition containing the small-diameter particles and the composition containing the large-diameter particles, the amounts used, the average particle diameters, and the mixing ratios of the two compositions. A film was obtained from the obtained aqueous coating composition in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Comparative Example 1 (Production of Composition Containing Small Particle Size) In a reaction vessel, 270 parts by weight of Epicoat EP-1010 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, methoxypropanol 305 parts by weight were charged, and the temperature was gradually increased while stirring, and 110 ° C.
The epoxy resin was dissolved in 2 hours. A monomer solution consisting of 24 parts by weight of methacrylic acid, 3 parts by weight of styrene, 3 parts by weight of ethyl acrylate, 5 parts by weight of benzoyl peroxide and 15 parts by weight of toluene was added to a solution of phenoxy resin at 105 parts.
~ 110 ° C, dropped in 2 hours, further 105 ~ 110 ° C
For 3 hours. Shownor CKS
18 parts by weight of -394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 25 parts by weight of dimethylethanolamine and 2345 parts by weight of deionized water was added to 70 parts by weight.
The mixture was added dropwise to the reaction solution with stirring at 2 ° C. for 2 hours to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and the non-volatile
%, A composition (I-9) containing small-diameter particles having an average particle diameter of 387 nm was obtained. Tables 1 and 2 show the raw materials of the composition, the amount used and the average particle size, and the mixing ratio of the two compositions.

A film was obtained from the obtained composition (I-9) in the same manner as in Example 1. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Comparative Example 2 (Production of Composition Containing Small Particle Size) Epitope YD-020H (Epoxy resin, manufactured by Toto Kasei Co., Ltd.) was placed in a reaction vessel.
35 parts by weight, 135 parts by weight of phenotote YP-50S (manufactured by Toto Kasei Co., Ltd., phenoxy resin), 77 parts by weight of diethylene glycol monobutyl ether, and 305 parts by weight of methoxypropanol were charged, and the temperature was gradually increased while stirring, and 110 ° C. The epoxy resin and phenoxy resin were dissolved in 2 hours. 24 parts by weight of methacrylic acid, styrene 3
A monomer solution composed of 3 parts by weight of ethyl acrylate, 5 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene was added dropwise to the above solution at 105 to 110 ° C. for 2 hours, and further stirred at 105 to 110 ° C. for 3 hours. Continued. Furthermore, 18 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 25 parts by weight of dimethylethanolamine and 2345 parts by weight of deionized water was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure to obtain a composition (I-10) containing small particles having a nonvolatile content of 35% and an average particle diameter of 220 nm. Raw materials for the composition,
The amounts used, the average particle size, and the mixing ratio of the two compositions are shown in Tables 1 and 2.

From the composition (I-10) obtained, Example 1 was obtained.
A coating was obtained in the same manner as described above. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Comparative Example 3 (Production of Composition Containing Small Particle Size) In a reaction vessel, 210 parts by weight of phenotote YP-50S (Phenoxy resin manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, methoxypropanol 305 The weight was gradually increased while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. Methacrylic acid 45 parts by weight,
24 parts by weight of styrene, 21 parts by weight of ethyl acrylate,
A monomer solution consisting of 9 parts by weight of benzoyl peroxide and 15 parts by weight of toluene was added dropwise to the above solution at 105 to 110 ° C. for 2 hours, and stirring was continued at 105 to 110 ° C. for 3 hours. Furthermore, 18 parts by weight of Shaunol CKS-394 (manufactured by Showa Polymer Co., Ltd., resol type phenol resin) was added to the above reaction solution, and the mixture was reacted at 120 ° C. for 3 hours to precondensate the phenol resin. The reaction solution was cooled to 70 ° C., and an aqueous solution consisting of 30 parts by weight of dimethylethanolamine and 2339 parts by weight of deionized water was added dropwise to the reaction solution at 70 ° C. for 2 hours while stirring to carry out dispersion. Thereafter, the solvent and water were removed under reduced pressure to obtain a nonvolatile content of 35% and an average particle size of 3%.
A composition (I-11) containing particles having a small particle diameter of 87 nm was obtained. Tables 1 and 2 show the raw materials of the composition, the amount used and the average particle size, and the mixing ratio of the two compositions.

From the composition (I-11) obtained, Example 1
A coating was obtained in the same manner as described above. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

Comparative Example 4 (Production of Composition Containing Large Particles) In a reaction vessel, 270 parts by weight of phenotote YP-50S (Phenoxy resin manufactured by Toto Kasei Co., Ltd.), 77 parts by weight of diethylene glycol monobutyl ether, and methoxypropanol 305 were used. The weight was gradually increased while stirring, and the phenoxy resin was dissolved at 110 ° C. for 2 hours. A monomer solution consisting of 9 parts by weight of methacrylic acid, 9 parts by weight of styrene, 12 parts by weight of ethyl acrylate, 4 parts by weight of benzoyl peroxide, and 15 parts by weight of toluene is added to a phenoxy resin solution at a rate of 105 to 110 parts.
C., the mixture was added dropwise at 2 hours, and stirring was continued at 105 to 110 ° C. for 3 hours. In addition, Shaunor CKS-39
4 (Resole type phenolic resin, manufactured by Showa Polymer Co., Ltd.) 18
A part by weight was added to the above reaction solution and reacted at 120 ° C. for 3 hours to pre-condense the phenol resin. Reaction solution 70
After cooling to 10 ° C., an aqueous solution comprising 10 parts by weight of dimethylethanolamine and 2361 parts by weight of deionized water was added dropwise to the reaction solution while stirring at 70 ° C. for 2 hours to perform dispersion. Thereafter, the solvent and water were removed under reduced pressure, and a composition containing large-diameter particles having a nonvolatile content of 35% and an average particle diameter of 897 nm (II-
9) was obtained. Tables 1 and 2 show the raw materials of the composition, the amount used and the average particle size, and the mixing ratio of the two compositions.

From the composition (II-9) obtained, Example 1
A coating was obtained in the same manner as described above. In the same manner as in Example 1, the stability of the obtained aqueous coating composition, the retort resistance, workability, corrosion resistance, and paintability of the baked film were evaluated. Table 3 shows the results.

[0090]

[Table 1]

[0091]

[Table 2]

[0092]

[Table 3]

[0093]

The aqueous coating composition of the present invention is excellent in storage stability and coatability. Further, by mixing two compositions having different average particle diameters, the uniformity of the coating is improved, and a coating excellent in processability, retort property and coatability is obtained. Therefore, the present invention can be suitably applied to so-called end materials such as the inner surface of food and beverage cans and lids. Further, the present invention can be applied not only to the inner surface of a can, but also to building materials, home appliances, automobile parts, and the like.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for testing the workability of a coating film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Test piece 2 Aluminum plate 3 Coating 4 Processing part

Continued on the front page (72) Inventor Tamio Iimure 4-1-1-15 Minamishinagawa, Shinagawa-ku, Tokyo Inside Japan Paint Co., Ltd. Tokyo Office

Claims (14)

[Claims] 1. A carboxylic acid-modified epoxy resin (C) obtained by polymerizing a monomer mixture (B) of an unsaturated carboxylic acid monomer and a radical polymerizable unsaturated monomer on a bisphenol type epoxy resin (A). ) Is dispersed in an aqueous medium in the presence of a basic substance, and has an average particle size of 1
An aqueous coating composition obtained by mixing an aqueous resin composition (a) having a particle size of 00 to 400 nm and an aqueous resin composition (b) having an average particle diameter of 600 to 1000 nm. 2. The mixing ratio of the aqueous resin composition (a) and the aqueous resin composition (b) is 1 in terms of solid content ratio (weight ratio) in the composition.
The aqueous coating composition according to claim 1, which is 0/90 to 90/10. 3. Bisphenol type epoxy resin (A)
Is a high molecular weight bisphenol type epoxy resin having a number average molecular weight of 10,000 to 50,000 (A1) and / or a low molecular weight bisphenol type epoxy resin having a number average molecular weight of less than 500 to 10,000 (A2). 2. The aqueous coating composition according to 1. 4. A high molecular weight bisphenol type epoxy resin (A1) and a low molecular weight bisphenol type epoxy resin (A
The aqueous coating composition according to claim 3, wherein the weight ratio of 2) is from 100: 0 to 50:50. 5. The aqueous coating composition according to claim 3, wherein the high molecular weight bisphenol type epoxy resin (A1) has an epoxy equivalent of 7,500 to 75,000. 6. The aqueous coating composition according to claim 3, wherein the low molecular weight bisphenol type epoxy resin (A2) has an epoxy equivalent of 250 to 9,000. 7. The acid value of the monomer mixture (B) is from 260 to 6.
The aqueous coating composition according to claim 1, which is 00. 8. The weight ratio [(A) / (B)] of the bisphenol type epoxy resin (A) to the monomer mixture (B) is 75.
The aqueous coating composition according to claim 1, wherein the ratio is from / 25 to 95/5. 9. The aqueous coating composition according to claim 1, further comprising a phenol resin and / or an amino resin (D). 10. The aqueous coating composition according to claim 9, wherein the phenol resin and / or the amino resin (D) is condensed with the carboxylic acid-modified epoxy resin (C). 11. The aqueous coating composition according to claim 1, further comprising a diol having 2 to 4 carbon atoms as a diluent. 12. The aqueous coating composition according to claim 11, wherein the diol is a diol having 4 carbon atoms. 13. The aqueous coating composition according to claim 1, which is used for applying an inner surface of a can end material. 14. A coating film formed by applying the aqueous coating composition according to claim 1 to an object to be coated.