JPS6368678A - Electrodeposition paint composition - Google Patents

Abstract

PURPOSE:To provide an electrodeposition paint compsn. which has excellent dispersion stability and gives a coating film having excellent resistance to water and corrosion, etc., by uniformly dispersing fine resin particles having a specified particle size and a specified SP value in an aq. dispersion of an aq. electrodepositable resin. CONSTITUTION:The title electrodeposition paint compsn. contains an aq. dispersion of an aq. electrodepositable resin (A) (e.g., maleinized polybutadiene) and fine resin particles (B) which have a particle size of 0.01-0.2mu and an SP value different from that of the component A by 1 or smaller and are uniformly dispersed in the component A as essential ingredients. The resin particles are used in an amount of 1-50wt% bad on that (on a solid basis) of the aq. resin. The resin particles can be prepd., e.g., by emulsion-polymerizing an ethylenically unsaturated monomer (e.g., methyl acrylate) to form a dispersion contg. fine resin particles and isolating the resin particles.

Description

[Detailed Description of the Invention] (2) Electrodeposition paints are widely used as undercoats with anticorrosive properties because of their workability regardless of shape and their safety. Electrodeposition paints are in the form of resins dispersed or dissolved in water as a medium, so controlling their stability and throwing power through energization is necessary to stabilize the coating line. Regarding other parts of the coating, especially in fields where high corrosion resistance and chipping resistance are required, such as automobile coating systems, coatings with high film thickness and high performance physical properties are desired. . In addition, as consumers have recently become more conscious of high-quality products, there has been a strong desire for high-quality paint films, and there is a strong need for paint films that have higher definition and higher gloss than ever before.

Conventionally, in electrodeposition paints, especially emulsion-based electrodeposition paints, phase separation of the base resin itself has often been a problem.

Possible methods to reduce the tendency for phase separation include the use of surfactants and increasing the number of hydrophilic groups introduced into the base resin, but these methods do not affect coating performance, such as water resistance. and has a negative effect on corrosion resistance. Therefore, it is an object of the present invention to improve the dispersion stability of the base resin without sacrificing the coating performance or adversely affecting other properties of the electrodeposition paint.

Ryuo method The above-mentioned problem is to add micro resin particles having a relatively small particle size and an SP value relatively close to the SP value of the base resin into an aqueous dispersion of an electrodepositable aqueous resin (base resin). Solved by adding

Therefore, the present invention comprises: (a) an aqueous dispersion of an aqueous resin capable of electrodeposition; and (b)
SP particles having a particle size of 0.01 to 0.2μ, which are uniformly dispersed in the aqueous dispersion of the aqueous resin, and which are bonded to the aqueous resin.
Provided is an electrodeposition coating composition characterized in that it contains as an essential component fine resin particles whose values differ by 1 or less.

Since the micro resin particles are small, they adhere to the surface of the water-based resin emulsion particles in the coating liquid, modifying the state of charge, and improving the dispersion stability of the emulsion particles.
The fine resin particles themselves have high compatibility with the aqueous base resin, so they are stably dispersed in the paint, contributing to improving the stability of the paint as a whole. Since the fine resin particles become part of the film-forming resin component, they do not adversely affect other properties of the paint or coating film.

The present invention is applicable to both cationic and anionic electrodeposition paints. Electrodepositable aqueous resins (base resins) are generally film-forming resins that have functional groups that provide the charge and hydrophilicity necessary for electrodeposition. They are classified into aqueous solution type, dispersion type, emulsion type, and suspension type, mainly depending on their form when dispersed in water, and herein they are collectively referred to as aqueous resin.

Various types of water-based resins are known for use in electrodeposition paints, and any of these known water-based resins can be used in the present invention.

The water-based resin used in anionic electrodeposition paints has anionic functional groups such as carboxyl groups in order to give the resin the negative charge and hydrophilicity necessary for electrodeposition. Typical such resins include maleated natural or synthetic drying oils,
maleated polybutadiene, their halfesters,
Half amide etc.

The water-dispersible resin used in cationic electrodeposition paints has a cationic functional group such as an amine group to impart positive charge and hydrophilicity. Various types of resins are known, such as epoxy resins, polyether resins, polyester resins, polyurethane resins, polyamide resins, and polybutadiene resins.

These resins, according to their curing reaction mechanism,
There are self-crosslinking types that are cured by the resin itself through radical polymerization or oxidative polymerization, hardening agent types that are hardened by using a hardening agent such as melamine resin or profukubolyisocyanate compounds, and types that use a combination of both. .

Furthermore, according to the type of curing energy, it can be classified into types such as room temperature curing, heat curing, and radiant energy curing such as ultraviolet rays and electron beams.

Furthermore, for the purpose of improving coating performance, resins that do not have functional groups that impart charge and hydrophilicity, such as epoxy acrylate resins, are also used in combination with the hydrophilic resins in the form of an emulsion.

In the present invention, a system in which such a curing agent is used in combination with a resin having no hydrophilic functional group is also referred to as an aqueous resin.

Such electrodepositable aqueous resins are well known to those skilled in the art and do not require further explanation as such do not form part of the present invention.

Various methods have been proposed to produce microscopic resin particles, one of which is the production of ethylenically unsaturated monomers and/or
Alternatively, a fine resin particle dispersion is obtained by suspension polymerization or emulsion polymerization of a crosslinkable copolymerized ffimer in an aqueous medium.
Ethylenically unsaturated monomers and/or crosslinkable copolymers in non-aqueous organic solvents that dissolve monomers but not polymers, such as P organic solvents or high SP organic solvents such as esters, ketones, alcohols, etc. This is a method called the NAD method or precipitation method, in which the resulting fine resin particle copolymer is copolymerized with the NAD method or precipitation method.

The fine resin particles of the present invention may be produced by any of the above methods.

Examples of ethylenically unsaturated monomers include acrylic acids such as methyl (meth)acrylate, ethyl (meth)acrylate, isobutyl (meth)acrylate, isobutyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. or alkyl esters of methacrylic acid or other monomers having ethylenically unsaturated bonds that can be copolymerized with them, such as styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, ethylene, propylene, vinyl acetate, Examples include vinyl propionate, acrylonitrile, methacrylate trile, and dimethylaminoethyl (meth)acrylate. Two or more types of these monomers may be used.

Crosslinkable comonomers are monomers and/or monomers having two or more radically polymerizable ethylenically unsaturated bonds in the molecule.
Alternatively, it contains two types of ethylenically unsaturated group-containing monomers each carrying groups that can react with each other.

Monomers having a radically polymerizable ethylenically unsaturated group of H[Ii1 or more in the molecule include polymerizable unsaturated monocarboxylic acid esters of polyhydric alcohols, polymerizable unsaturated alcohol esters of polybasic acids, and There are aromatic compounds substituted with two or more vinyl groups, examples of which include the following compounds.

Ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol dimethacrylate Acrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol dimethacrylate , glycerol diacrylate, glycerol allyloxy dimethacrylate, 1,1.1-) lishydroxymethylethane diacrylate, 1. Ll-) Lishydroxymethylethane triacrylate, 1.1.1
~Trishydroxymethylethane dimethacrylate, 1
．． 11-trishydroxymethylethane trimethacrylate, 1,1.1-trishydroxymethylpropane diacrylate, 1.1.1-trishydroxymethylpropane triacrylate, 1,1.1-trishydroxymethylpropane dimethacrylate, 1. 1.1-
Trishydroxymethylpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl phthalate and divinylbenzene.

In addition, examples of monomers having two types of ethylenically unsaturated groups each carrying mutually reactive groups include epoxy group-containing ethylenically unsaturated monomers such as glycidyl acrylate and glycidyl methacrylate, and acrylic acid and methacrylic acid. Carboxyl group-containing ethylenically unsaturated monomers such as acid and crotonic acid are the most representative, but mutually reactive groups are not limited to these.
For example, various compounds have been proposed, such as amine and carbonyl, epoxide and carboxylic acid anhydride, amine and carboxylic acid chloride, alkyleneimine and carbonyl, organoalkoxysilane and carboxyl, hydroxyl and isocyanate, etc., and the present invention broadly encompasses these. It is something to do.

Micro resin particles produced in an aqueous medium or a non-aqueous organic medium can be isolated by a method such as filtration, spray drying, or freeze drying, and then cut into appropriate particle sizes by using a mill or the like. It can be used after being pulverized, or the synthesized dispersion can be used as it is or by replacing the medium by solvent replacement.

Generally speaking, it is desirable to control the particle size of the particles obtained by the polymerization method. 0.01~0.2μ
Emulsion polymerization method and NAD method are suitable for the particles.

The SP value of the fine resin particles can be controlled by the composition of the seven-mer mixture. In particular, in the case of copolymers of ethylenically unsaturated monomers, it can be determined by calculation from the types of monomers and their proportions.

In order to maintain a stable dispersion state in paints and electrodeposition baths, the microscopic resin particles preferably have ionizable groups with the same polarity as the aqueous resin that is the base resin. It is preferable to carry an anionic group such as a carboxyl group or a sulfonic acid group, and in the case of cationic electrodeposition, it is preferable to carry a cationic group such as an amino group or a quaternary ammonium group. Monomers having unsaturated bonds and carboxyl groups, such as acrylic acid and methacrylic acid; monomers having ethylenically unsaturated bonds and basic groups, such as dimethylaminoethyl (meth)acrylate, vinylpyridines, etc. is added to the monomer mixture during the synthesis of minute resin particles, or
Alternatively, for the synthesis of fine resin particles, there is a method of polymerizing a monomer mixture using an initiator that provides a cationic end.

If the polymer itself that makes up the micro resin particles is non-polar, use an appropriate emulsifier during synthesis of the micro resin particles, especially oligosoaps, polysoaps, or reactive emulsifiers that have amphoteric ionic groups to stably disperse the micro resin particles. You can also do it. These emulsifiers having amphoteric ionic groups are described in Japanese Patent Application Laid-open Nos. 56-24461 and 57-21927. 57-40522, etc.

Silkworm 11 Material ■ Charcoal Belly The electrodeposition coating composition of the present invention contains the above-mentioned electrodepositable aqueous resin and the above-mentioned fine resin particles as essential components. The ratio of the aqueous resin to the fine resin particles is 1 to 50% by weight of the latter based on the solid content of the former. If the amount of fine resin particles added is too small, there will be no effect, and if it is too large, the stability of the paint and the workability of electrodeposition will be impaired.

Depending on the type of water-dispersible resin used, it may also contain auxiliary hardeners such as melamine resins, benzoguanamine resins, phenolic resins, blocked polyisocyanate compounds, and metal compounds such as manganese, cobalt, copper, lead, and tin as catalysts. These components that can be used are dispersed in an aqueous medium containing a base for anionic electrodeposition and an acid for cationic electrodeposition. These acids and bases are used to neutralize the electrodepositable water-soluble resin.

Examples of the base used for neutralization include ammonia, jetanolamine, triethanolamine, methylethanolamine, diethylamine, morpholine, and potassium hydroxide.

As the acid, phosphoric acid, acetic acid, propionic acid, lactic acid, etc. are used.

The aqueous medium is water or a mixture of water and a water-miscible organic solvent. If necessary, the aqueous medium may contain a water-immiscible organic solvent. Examples of water-miscible organic solvents include ethyl cellosolve, probyl cellosolve, butyl cellosolve,
Examples include ethylene glycol dimethyl ether, diacetone alcohol, 4-methoxy-4-methylpentanone-2, and methyl ethyl ketone. Examples of water-immiscible organic solvents include xylene, toluene, methyl isobutyl ketone, and 2-ethylhexanol.

The coating composition of the present invention can contain pigments.

Examples include coloring pigments such as titanium dioxide, red iron oxide, carbon black, extender pigments such as aluminum silicate, precipitated barium sulfate, and aluminum phosphomolybdate, strontium chromate, basic lead silicate, lead chromate, etc. There are anti-rust pigments.

The coating composition of the present invention has a non-volatile content of the coating of 10 to 20%.
It can be electrodeposited to a dry film thickness of 15 to 30 μm and cured by room temperature curing, heat curing, ultraviolet curing, electron beam curing, etc. depending on the type of resin.

Production examples, examples and comparative examples of the present invention are shown below. Parts and percentages in these examples are by weight.

Production Example 1 73.5 parts of sodium salt of taurine, 100 parts of ethylene glycol, and 200 parts of ethylene glycol monomethyl ether were added to a 21-kolben equipped with a stirrer, a nitrogen inlet tube, a temperature control device, a condenser, and a decanter. Prepare and heat while stirring to raise the temperature to 120℃. After the contents reached a uniform state of dissolution, a solution consisting of 470 parts of Epicor 1001 (manufactured by Shell Chemical Co., diglycidyl ether type epoxy resin of bisphenol A, epoxy equivalent: 470) and 400 parts of ethylene glycol monomethyl ether was added to 2 Drip in time. After dropping, stirring and heating were continued for 20 hours to obtain 518 parts of a modified epoxy resin.

The acid value of this resin by KOH titration was 49.4, and the fluorescent
The sulfur content by line analysis was 2.8%.

Into 11 reaction vessels equipped with a stirrer, a cooling tube, and a temperature control device, 306 parts of deionized water and 7 parts of the modified epoxy resin obtained above were added.
．． 5 parts, dimethylethanolamine 1.0 parts,
The temperature was raised to 80°C while stirring. After the contents were dissolved, the temperature was maintained at 80°C while stirring, and an aqueous solution consisting of 4.8 parts of azobiscyanovaleric acid, 4.56 parts of dimethylethanolamine, and 48 parts of salt ion water was charged therein, and then 85% of styrene was added. 7 parts of methyl methacrylate, 114.3 parts of n-butyl acrylate, 57.1 parts of n-butyl methacrylate, and 14.3 parts of diethylaminoethyl methacrylate.
The dropwise addition took 0 minutes. After dropping, add 1.2 parts of azobiscyanovaleric acid and 1 part of dimethylethanolamine at the same temperature.
．． Add a mixed aqueous solution consisting of 14 parts of deionized water and 12 parts of deionized water and continue stirring for 60 minutes to obtain a particle size of 123 nm, S
P value 10.1. A fine resin dispersion with a nonvolatile content of 35% was obtained.

Production Example 2 Nisseki Polybutadiene B-2000 (number average molecular weight 200
0°1.2 bonds (65%) was epoxidized using peracetic acid to produce epoxidized polybutadiene with an oxirane oxygen content of 6.4%.

After charging 1000 g of this epoxidized polybutadiene and 354 g of ethyl cellosolve into a 21 autoclave, 62.1 g of dimethylamine was added and reacted at 150° C. for 5 hours. After distilling off unreacted amine, it was cooled to 120°C and 79.3 g of acrylic acid and 7.6 g of hydroquinone were added.
A mixture of 26.4 g of ethyl cellosolve and 26.4 g of ethyl cellosolve was added thereto, and the mixture was further reacted at 120° C. for 3 hours and 45 minutes to produce a resin solution (A). The amine value of this product was 85.2 mmol/100g, the acid value was 10.0 mmol/100g, and the solid content concentration was 75.0% by weight.

Production Example 3 1000 g of a bisphenol type epoxy resin having an epoxy equivalent weight of 950 (trade name Epicote 1004 oil-based Ciel Epoxy @!I) was dissolved in 343 g of ethyl cellosolve, and 76.3 g of acrylic acid, 10 g of hydroquinone and N,N-dimethylamine ethanol were dissolved. Add 5g of
The resin solution (B> was synthesized by heating to 00°C and reacting for 5 hours. Solid content concentration 75% by weight. Production example 4 Nisseki Polybutadiene B-1000 (number average molecular weight 100
0, 1.2 bonds 60%) 1000g, maleic anhydride 2
65.8 g of xylene, 10 g of xylene, and Antigen 6C (trade name of Sumitomo Chemical) Ig were placed in a 2E separable flask equipped with a reflux condenser and reacted at 190°C for 5 hours under a nitrogen stream. Next, unreacted maleic anhydride, Xylene was distilled off under reduced pressure to synthesize maleated polybutadiene with an acid value of 214 mmol/100 g.

Next, maleated polybutadiene tooog and 212.4 g of ethyl cellosolve were charged into a 21 separable flask equipped with a reflux condenser and reacted at 120°C for 2 hours with stirring to produce a half-esterified product (C) of maleated polybutadiene. . Solid content concentration 98% by weight Example 1 400 g of (A) produced in Production Example 2, 240 g of (B) produced in Production Example 3, and (C) 19 produced in Production Example 4
．． 2g were mixed until homogeneous.

Varnish Sp(+iHo,s) was added, and then 8.1 g of acetic acid was added and thoroughly stirred to neutralize.

1,835 g of ionized water was gradually added to this varnish to obtain an emulsion with a solid content concentration of about 20%.

Thereafter, 200 g of the fine resin dispersion of Production Example 1 was added to prepare an aqueous solution having a solid content concentration of about 20% (about 3% solids of the fine resin particles in the paint bath).

Using the above electrodeposition coating solution, a carbon electrode was used as an anode, and a zinc phosphate treated plate was closed as a cathode, and cathode deposition type tube coating was performed at 100V for 3 minutes. Baking at 175℃ x 30 minutes. The test results are shown in Table-1.

Manufacturing example 5 4 Ammonium E 1800-6.5 (made by Nippon Oil ■).

(epoxidized polybutadiene) 1000g butyl cellosolve 349g dimethylamine 46g 50% lactic acid
138g deionized water
473g phenyl glycidyl ether 117g epoxidized polybutadiene E 1
After charging 800-6.5 and butyl cellosolve into an autoclave, dimethylamine was added and reacted at 150°C for 5 hours. After distilling off the unreacted amine, it was cooled to 60°C, and a mixture of 50% lactic acid and deionized water was added.
After that, stir and keep warm at 80°C for 30 minutes. After that, phenylglycidyl ether was added, the temperature was raised to 110°C, and while stirring and keeping warm, the acid value of the contents was measured by the usual method using phenolphthalene as an indicator and alcoholic KoH as a standard solution, and acid fil! After reacting until confirmation of io, 1 or less, production is terminated. Non-volatile content 55% Production Example 6 Dish Katsuji Production Example 5 Varnish 231g Deionized water 315g Carbon blank 16g Titanium oxide 92g Kaolin 220g Basic lead silicate 58g After adding deionized water to the varnish of Production Example 5 and melting it. Add the pigment and mix with a disperser for about 1 hour. Glass peas are added to this mixture, and then dispersed in a sand mill to a particle size of 20 μm or less, and after the glass peas are divided into days, the production is completed. Non-volatile content 55% Example 2 400 g of (A) produced in Production Example 2, 240 g of (B) produced in Production Example 3, (c) 19.2 produced in Production Example 4
After mixing until homogeneous, 8.1 g of acetic acid was added and thoroughly stirred for neutralization. The tax on this varnish is 183 yen of ionized water.
5 g was gradually added to obtain an emulsion with a solid content concentration of about 20%. After that, the pigment paste 360 of Production Example 6
g, 550 g of deionized water, and 260 g of the fine resin particle dispersion of Production Example 1 were uniformly stirred to prepare an enamel electrodeposition bath (approximately 2% solid fine resin particles in the paint).

Using this electrodeposition bath, electrodeposition was carried out under the same conditions as in Example 1.
Table 1 shows the performance of the cured coating film.

Production Example 7 Nisseki Polyphytadiene B-1500* 1) 10
00g Antigen 6C* 2)
10 g maleic anhydride 25
0g deionized water 20g diethylamine 0.5g propylene glycol 100g ethyl cellosolve 340g*l) Nippon Petrochemical ■
Made: Mn 1500, vinyl 65%, trans 14
%, cis 16% *2) Manufactured by Sumitomo Chemical ■; N-methyl-N'-(1,3-
dimethylbutyl), p-phenylenediamine with cooling tube 2
6 stones polybutadiene B-1500100 in 1 Kolben
0 g, and add 10 g of Antigen 6C and 250 g of maleic anhydride. While stirring, heat the indoor bath to 190~2
The addition reaction of maleic acid to polybutadiene is carried out while maintaining the temperature at 00°C.

Approximately 5 hours after the temperature was raised, it was confirmed that the reaction was completed by a dimethylaniline color reaction. Thereafter, the internal temperature was cooled to 100° C., and a mixture of 20 g of deionized water and 0.5 g of diethylamine was added dropwise over about 30 minutes. Further, stirring was continued for about 1 hour after the completion of the dropwise addition, and the acid value was confirmed to be 140. After that, 100g of propylene glycol was added and heated to 110℃ for 3 hours.
It was confirmed that the total acid value was 125 after reacting for a period of time. Thereafter, 340 g of ethyl cellosolve was added, and after stirring at 80° C. for about 1 hour, the synthesis was completed. Non-volatile content 80% Production example 8 Evototo YD-01413) 9
50 g ethyl cellosolve 240
g Hydroquinone 10 g Acrylic acid 65 g Dimethylbenzylamine 5 g *3) Manufactured by Tobu Kasei@, epoxy resin, epoxy equivalent 950 Epotote YD-014950 in 21 Kolben with cooling tube
Add 240 g of ethyl cellosolve and 240 g of ethyl cellosolve and gradually reduce to 120 g.
Uniformly melt YD-014 while stirring at ℃. Then add 10g of hydroquinone and add 65g of acrylic acid.
g, and add 5 g of dimethylbenzylamine. After reacting at 120° C. for 4 hours, it was confirmed that the post-acid value was 1 or less.

Non-volatile content 80% Production Example 9 Add 426 ml of deionized water to a flask equipped with a stirrer and a thermometer.
and heated to 80°C. An aqueous solution consisting of 1 part of ammonium persulfate and 20 parts of deionized water was added dropwise under a nitrogen stream. Furthermore, a 7-mer mixture consisting of 5 parts of styrene and 5 parts of n-butyl acrylate was added, and after reacting for 10 minutes, an aqueous solution consisting of 1 part of ammonium persulfate and 20 parts of deionized water, 40 parts of methyl methacrylate, and n-butyl acrylate was added. 20 parts of methacrylate, 30 parts of styrene and 2-
A 7-mer mixture consisting of 10 parts of hydroxyethyl methacrylate was added dropwise over 60 minutes. Further temperature 8
The reaction was completed by keeping the temperature at 0°C for 2 hours.

A fine resin particle dispersion having a particle size of 320 nm, a softening temperature of 70° C., and a non-volatile content of 35% was obtained.

Production Example 10 125 g of the varnish from Production Example 7 was collected, 13 g of triethylamine was added thereto, and then 250 g of deionized water was gradually added to dissolve uniformly to obtain a varnish with a non-volatile content of 26%.

Next, 150 g of titanium dioxide and 50 g of lead silicate.

Strontium chromate) 25g, carbon black 2
Add 5g and stir with a disperser for about 1 hour. After glass peas are added to this mixture, they are dispersed in a sand mill to a particle size of 20 μm or less, and the glass peas are divided into days to complete the production. Non-volatile content 55% Example 3 125 g of varnish from Production Example 7, 75 g of varnish from Production Example 8
, butylated melamine (50% non-volatile content), 40 g of resol type phenolic resin (50% non-volatile content) were collected, 2 g of nonionic surfactant and 3 g of cobalt naphthenate were added thereto, stirred uniformly, and triethylamine 1.
Then, 707 g of salt ion water was gradually added and dissolved by stirring uniformly. 47 g of the fine resin particle dispersion of Production Example 9 was added, and the solid content concentration was approximately 20% (fine resin particle dispersion in the paint). A paint bath of approximately 2% liquid was prepared.

A dull steel plate treated with zinc phosphate is immersed in a paint bath, and the object to be coated is used as an anode.Membrane J! Electrodeposition coating was applied to 220μ. Thereafter, the surface of the object to be coated was washed with water and baked in a baking oven at 140° C. for 30 minutes to obtain a coated plate with a film thickness of 20 μm. Table 1 shows the results of testing the performance of the obtained coating film.

Example 4 125 g of the varnish of Production Example 7, 75 g of the varnish of Production Example 8,
40 g of butylated melamine (50% non-volatile content) and 40 g of resol type phenol resin (50% non-volatile content) were collected, and 2 g of nonionic surfactant and 3 g of cobalt naphthenate were added thereto and stirred uniformly, followed by 13 g of triethylamine.
Then, 707 g of deionized water was gradually added and dissolved by stirring uniformly, and then 125 g of the pigment paste of Production Example 10, 220 g of salt ionized water, and 80 g of the fine resin particle dispersion of Production Example 9 were uniformly added. With stirring, the enamel electrodeposition bath (approximately 10% solids of microscopic resin particles in the paint) was added to the milliliter of the enamel electrodeposition bath.

Using this electrodeposition bath, electrodeposition was carried out under the same conditions as in Example 3.
Table 1 shows the performance of the cured coating film.

Comparative Example 1 The same procedure as in Example 1 was carried out except that 200 g of the fine resin particles of Production Example 1 were not added and 1,835 g of the ionized water was changed to 1,800 g.

Comparative Example 2 The same procedure as in Example 2 was carried out except that 260 g of the fine resin particles of Production Example 1 were not added and 1835 g of salt ionized water was changed to 1800 g.

Comparative Example 3 The same procedure as in Example 3 was carried out except that 60 g of the fine resin particles of Production Example 10 were not added and 707 g of deionized water was changed to 662 g.

Comparative Example 4 The same procedure as in Example 4 was carried out except that 80 g of the fine resin particles of Production Example 10 were not added and 707 g of deionized water was changed to 662 g.

(Leaving space below) Procedural amendment October 9, 1988 Patent Application No. 214889 2 Name of the invention Electrodeposition paint composition 3 Relationship with the person making the amendment Name of patent applicant Title Nippon Paint Co., Ltd. 4. Spontaneous request by the agent 6. No increase in the number of inventions due to the amendment Contents of the amendment 1. Correct "Nippon Oil ■" in the second line from the bottom of page 19 of the specification to "Nippon Petrochemical ■".

2. "... after mixing" on page 21, line 14
Next to ``(varnish SPPtO26) insert J.

3. Delete "anionicity" on page 24, line 8.

4. r320nm, softening temperature 70℃ on page 25, line 2
," is corrected to r196nm, SPPtO21,J.

5. Insert ``(varnish SPPtO25)J'' after ``to this'' in the 1st and 18th lines of page 26.

6. On page 27, line 5, "solid content approximately 10%" is corrected to "solid content approximately 2%."

Claims (5)

[Claims] (1) (a) an aqueous dispersion of an electrodepositable aqueous resin; and (b)
) Fine resin particles uniformly dispersed in the aqueous dispersion of the aqueous resin and having a particle size of 0.01 to 0.2 μ and a difference in SP value from the aqueous resin of 1 or less are essential components. An electrodeposition coating composition comprising: (2) The electrodeposition coating composition according to item 1, wherein the aqueous dispersion of the electrodepositable aqueous resin is an emulsion. (3) The electrodeposition coating composition according to item 1 or 2, wherein the aqueous resin has a cationic group. (4) The electrodeposition coating composition according to item 1 or 2, wherein the aqueous resin has an anionic group. (5) The electrodeposition coating composition according to any one of items 1 to 4, wherein the amount of the fine resin particles is 1 to 50% by weight of the solid content of the aqueous resin.