JPH0255467B2 - - Google Patents

Description

[Detailed description of the invention]

Background and Problems of the Present Invention 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 resin dispersed or dissolved in water as a medium, so controlling the throwing power by energization is necessary to ensure safety and stabilize the coating line. Regarding its performance as a coating film, coating films with high film thickness and high performance physical properties are desired, particularly in fields where high corrosion resistance and chipping resistance are required, such as automotive coating systems. 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. It is conventionally known that the throwing power of electrodeposition paints can generally be controlled by pigment particles. Alternatively, a water-soluble resin that can be electrodeposited may be used as a base resin, and a resin powder used for powder coatings may be added to it (for example, Japanese Patent Application Laid-open No. 58-47067), or a resin that has a functional group that crosslinks with the water-soluble base resin. It has been proposed to obtain an electrodeposition paint with good throwing power by adding an emulsion (for example, JP-A-55-135180).
Although it has also been proposed to add powdered or particulate resins to electrocoat paints for various other purposes (e.g. Japanese Patent Publication Nos. 56-49766 and 58-93762), they generally contain conventional pigments or resin particles. Electrodeposition paints have problems such as insufficient throwing power, adverse effects on other properties such as the storage stability and appearance of the paint, and limitations on only specific types of electrodeposition paints. Therefore, an object of the present invention is to provide an electrodeposition paint composition that can be applied to any type of electrodeposition paint and exhibits excellent throwing power without adversely affecting other properties of the paint. . Solution The above-mentioned problem is solved by adding a material having a relatively large particle size to an aqueous dispersion of an aqueous resin (base resin) that can be electrodeposited.
This problem can be solved by uniformly dispersing fine resin particles that do not disintegrate due to Joule heat caused by electrodeposition. That is, the present invention comprises: (a) an aqueous dispersion of an aqueous resin that can be electrodeposited; and (b) particles having a particle size of 0.2 to 20 μ and a softening point uniformly dispersed in the aqueous dispersion of the aqueous resin. Provided is an electrodeposition coating composition characterized in that it contains as an essential component fine resin particles whose temperature is 10° C. or more higher than the temperature of an electrodeposition bath liquid. The fine resin particles serve as a filling effect for conventional pigments, and exhibit better throwing power than conventional pigments. Furthermore, since the softening point of the micro resin particles is more than 10°C higher than the bath temperature of the electrodeposition bath liquid, the Joule heat (usually 7 to 8
Because the particles maintain their shape without melting due to the temperature rise (accompanied by a temperature rise of 100.degree. C.), the effect of improving throwing power is not lost. The technology of the present invention is not limited to a specific type of electrodeposition paint, but can be applied to a wide range of electrodeposition paints in general, and since the fine resin particles become part of the film-forming resin component, it can be applied to other types of paints and coatings. There is no adverse effect on the performance of Detailed Discussion Electrodepositable Aqueous Resins The present invention is applicable to both cationic and anionic electrodeposition coatings. 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 are maleated natural or synthetic drying oils, maleated polybutadiene, half esters, half amides thereof, and the like. The water-based resin used in cationic electrodeposition paints has cationic functional groups such as amino groups to give it positive charge and hydrophilicity. Various types of resins such as epoxy resins, polyether resins, polyester resins, polyurethane resins, polyamide resins, and polybutadiene resins are known as examples of such resins. Depending on the mechanism of the curing reaction, these resins can be of the self-crosslinking type, in which the resin itself is cured by radical polymerization or oxidative polymerization, or in combination with a curing agent, such as a melamine resin or a block polyisocyanate compound. There are curing agent types that harden when used in combination, and types that use both in combination. 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 film performance, resins that do not have functional groups that impart charge and hydrophilicity, such as epoxy acrylate resins, are used in combination with the hydrophilic resins in the form of emulsions. 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. Micro resin particles Various methods have been proposed to produce micro resin particles, one of which involves suspending ethylenically unsaturated monomers and/or crosslinkable comonomers in an aqueous medium. A fine resin particle dispersion is obtained by polymerization or emulsion polymerization.Other methods use low SP organic solvents such as aliphatic hydrocarbons or high SP organic solvents such as esters, ketones, alcohols, etc.
Ethylenically unsaturated monomers and/or crosslinkable copolymers are copolymerized in a non-aqueous organic solvent that dissolves monomers but not polymers like organic solvents, and the resulting fine resin particle copolymer is dispersed. do
This method is called 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 methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Alkyl esters of acrylic acid or methacrylic acid and other monomers having ethylenically unsaturated bonds with which they can be copolymerized, such as styrene,
α-methylstyrene, vinyltoluene, t-butylstyrene, ethylene, propylene, vinyl acetate, vinyl propionate, acrylonitrile,
Examples include methacrylonitrile and dimethylaminoethyl (meth)acrylate. Two or more types of these monomers may be used. The crosslinkable copolymerizable monomer is a monomer having two or more radically polymerizable ethylenically unsaturated bonds in the molecule and/or two types of ethylenically unsaturated monomers each carrying mutually reactive groups. Contains group-containing monomers. Examples of monomers having two or more radically polymerizable ethylenically unsaturated groups in the molecule include polymerizable unsaturated monocarboxylic acid esters of polyhydric alcohols;
Examples include polymerizable unsaturated alcohol esters of polybasic acids and 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-trishydroxymethylethane diacrylate, 1,1,
1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylethane dimethacrylate, 1,1,1-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, two groups each carrying a group that can react with each other
Examples of monomers having ethylenically unsaturated groups include epoxy group-containing ethylenically unsaturated monomers such as glycidyl acrylate and glycidyl methacrylate, and carboxyl group-containing ethylenically unsaturated monomers such as acrylic acid, methacrylic acid, and crotonic acid. Saturated monomers 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. Fine 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 they can be reduced to an appropriate particle size 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, it is desirable to control the particle size of the particles obtained by the polymerization method. 0.2
For particles of ~0.6 μ, emulsion polymerization method and NAD method are
Precipitation polymerization is suitable for particles of 0.2-20μ. The softening point of the fine resin particles can be controlled by the monomer mixture composition, particularly the proportion of crosslinking monomer, and the molecular weight of the polymer. Generally, the higher the proportion of the crosslinking monomer and the higher the molecular weight after polymerization, the higher the softening point of the fine resin particles obtained. In order to maintain a stable dispersion state in the paint and the electrodeposition bath, the fine resin particles themselves preferably have ionizable groups having the same polarity as the aqueous resin that is the base resin. That is, in the case of anionic electrodeposition, it is preferable to support an anionic group such as a carboxyl group or a sulfonic acid group, and in the case of cationic electrodeposition, it is preferable to support a cationic group such as an amino group or a quaternary ammonium group. To achieve this, monomers having an ethylenically unsaturated bond and a carboxyl group, such as acrylic acid and methacrylic acid, and monomers having an ethylenically unsaturated bond and a basic group, such as dimethylaminoethyl (Meth)acrylates, vinylpyridines, etc. are added to the monomer mixture during the synthesis of minute resin particles, or the monomer mixture is polymerized using an initiator that provides a cationic end for the synthesis of minute resin particles. There is a way. 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 so. These emulsifiers having zwitterionic groups were disclosed in Japanese Patent Application Laid-Open No.
56-24461, 57-21927, 57-40522, etc. The fine resin particles are obtained by polymerizing the monofunctional ethylenically unsaturated monomer and/or crosslinkable monomer described above by solution polymerization or bulk polymerization, crushing the resulting polymer, and then classifying it into a predetermined particle size. You can also get it by doing so. As another method, in the case of fine resin particles such as epoxy resin, melamine resin, alkyd resin, etc., a liquid resin is emulsified and dispersed in water, and the emulsified resin dispersion is spray-dried to obtain a fine resin having a predetermined particle size. Alternatively, if the resin is solid, it can be pulverized and classified to form a fine resin with a predetermined particle size. Electrodeposition Coating Composition The electrodeposition coating composition of the present invention contains the electrodepositable aqueous resin and the fine resin particles as essential components. The ratio of aqueous resin and fine resin particles is 1 to 50% by weight of the former as solid content.
It is. 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 aqueous resin used, it may also contain auxiliary hardeners such as melamine resin, benzoguanamine resin, phenolic resin, blocked polyisocyanate compounds, and metal compounds such as manganese, cobalt, copper, lead, and tin as catalysts. can. These components 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, diethanolamine, triethanolamine, methylethanolamine, diethylamine,
Examples include 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, propyl cellosolve, butyl cellosolve, ethylene glycol dimethyl ether, diacetone alcohol, 4-
Examples include 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 titanium dioxide, red iron,
There are coloring pigments such as carbon black, extender pigments such as aluminum silicate and precipitated barium sulfate, and rust-preventing pigments such as aluminum phosphomolybdate, strontium chromate, basic lead silicate, and lead chromate. The coating composition of the present invention has a non-volatile content of the coating of 10 to 10%.
Adjust to about 20%, electrodeposit to a dry film thickness of 15 to 30μ,
Depending on the type of resin, it can be cured by room temperature curing, heat curing, ultraviolet curing, electron beam curing, etc. 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 Nisseki Polybutadiene B-1500 (*1) 1000g Antigen 6C (*2) 10g Maleic anhydride 250g Deionized water 20g Diethylamine 0.5g Propylene glycol 100g Ethyl cellosolve 340g (*1) Made by Nippon Petrochemical Co., Ltd.: Mn1500, vinyl
65%, trans 14%, cis 16% (*2) Manufactured by Sumitomo Chemical Co., Ltd.: N-methyl-N'-
(1,3-dimethylbutyl)-p-phenylenediamine Charge 1000 g of Nippon Polybutadiene B-1500 into a 2-kolben equipped with a cooling tube, and add 10 g of Antigen 6C and 250 g of maleic anhydride. While stirring,
The addition reaction of maleic acid to polybutadiene is carried out while maintaining the internal temperature at 190 to 200°C. Approximately 5 hours after the temperature was raised, it was confirmed that the reaction was completed by a methylaniline color reaction. After that, the internal temperature was cooled to 10℃, and a mixture of 20 g of deionized water and 0.5 g of diethylamine was added to the
Drop in 30 minutes. After the addition was completed, stirring was continued for about 1 hour, and the acid value was confirmed to be 140.
Then add 100g of propylene glycol and heat to 110℃.
The mixture was reacted for 3 hours and the total acid value was confirmed to be 125. Then add 340g of ethyl cellosolve and add 80g of ethyl cellosolve.
After stirring at °C for about 1 hour, the synthesis was completed. 8% non-volatile content. Production example 2 Epotote YD-014 (*3) 950g Ethyl cellosolve 240g Hydroquinone 10g Acrylic acid 65g Dimethylbenzylamine 5g (*3) Manufactured by Toto Kasei Co., Ltd., epoxy resin, epoxy equivalent 950 Epotote YD- in a 2-kolben with cooling tube 014
Add 950g and 240g of ethyl cellosolve and gradually
Uniformly dissolve YD-014 while stirring to 120℃. Then add 10 g of hydroquinone, and further add 65 g of acrylic acid and 5 g of dimethylbenzylamine. After reacting at 120°C for 4 hours, it was confirmed that the post-acid value was 1 or less. Nonvolatile content 80% Production Example 3 Production of anionic micro resin particles 426 parts of deionized water was placed in a flask equipped with a stirrer and a thermometer, and the temperature was 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, after adding a monomer mixture consisting of 5 parts of styrene and 5 parts of n-butyl acrylate and reacting for 10 minutes, an aqueous solution consisting of 1 part of ammonium persulfate and 20 parts of deionized water,
30 parts of styrene, 30 parts of methyl methacrylate, n-
A monomer mixed solution consisting of 30 parts of butyl methacrylate and 10 parts of 2-hydroxyethyl methacrylate was added dropwise over 60 minutes. Further temperature
The reaction was completed by keeping at 80°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 4 Pigment Paste 125g of the varnish from Production Example 1 was taken, 13g of triethylamine was added thereto, and then 250g of deionized water was added.
Gradually add g to dissolve it uniformly to make a varnish with a non-volatile content of 26%. Next, 150g of titanium dioxide, 50g of lead silicate, 25g of strontium chromate, and 25g of carbo black.
Add and mix with a disperser for about 1 hour. After glass beads are added to this mixture, they are dispersed in a sand mill to a particle size of 20μ or less, and after the glass beads are separated, the production is completed. Non-volatile content 55%. Example 1 125g of varnish from Production Example 1, 75g of varnish from Production Example 2
g, 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 13 g of triethylamine was collected. and then deionized water 707
20g of the fine resin particle dispersion of Production Example 3 was added, and the solid content concentration was approximately 20% (the solid content of the fine resin particles in the paint was approximately 20%).
%) paint bath was prepared. A dull steel plate treated with zinc phosphate was immersed in a paint bath, and electrodeposition was applied at 150V for 3 hours using the object to be coated as an anode. 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 about 20μ. The throwing power was evaluated according to the throwing power evaluation method described separately. Table 1 shows the results of testing the performance of the obtained coating film. Electrodeposition was carried out at a bath temperature of 30°C. same as below. Example 2 125g of varnish from Production Example 1, 75g of varnish from Production Example 2
g, 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 13 g of triethylamine was collected. and then deionized water 707
Gradually add 125g of the pigment paste of Production Example 4 and deionized water to dissolve it by stirring uniformly.
220g and 80g of the fine resin particle dispersion of Production Example 3 were uniformly stirred to prepare an enamel electrodeposition bath (solid content of fine resin particles in the paint was about 2%). Table 1 shows the performance of the coating film electrodeposited and cured using this electrodeposition bath under the same conditions as in Example 1 (however, at a coating voltage of 200 V). Production Example 5 Production of cationic micro resin particles In a 2-kolben equipped with a stirrer, nitrogen inlet tube, temperature control device, condenser, and decanter, 73.5 parts of sodium salt of taurine, 100 parts of ethylene glycol, and 200 parts of ethylene glycol monomethyl ether were added. Stir and heat to raise the temperature to 120℃. After the contents reach a uniform state of dissolution, Epikote 1001 (manufactured by Ciel Chemical Co., Ltd.,
A solution consisting of 470 parts of a diglycidyl ether type epoxy resin of bisphenol A (epoxy equivalent: 470) and 400 parts of ethylene glycol monomethyl ether was added dropwise over 2 hours. Stirring and heating are continued for 20 hours after dropping to obtain 518 parts of modified epoxy resin. The acid value of this resin by KOH titration was 49.4, and the sulfur content by fluorescent X-ray analysis was 2.8%. A reaction vessel equipped with a stirrer, a cooling tube, and a temperature control device was charged with 306 parts of deionized water, 7.5 parts of the modified epoxy resin obtained above, and 1.0 part of dimethylethanolamine, and the temperature was raised to 80°C while stirring. .
After the contents have dissolved, increase the temperature to 80℃ while stirring.
4.8 parts of azobiscyanovaleric acid,
An aqueous solution consisting of 4.56 parts of dimethylethanolamine and 48 parts of deionized water was charged, followed by styrene.
A mixed solution consisting of 85.7 parts of methyl methacrylate, 114.3 parts of methyl methacrylate, 28.6 parts of n-butyl acrylate, 57.1 g of n-butyl methacrylate, and 14.3 parts of diethylaminoethyl methacrylate was added dropwise over 60 minutes. After dropping, add azobiscyanovaleric acid at the same temperature.
Add a mixed aqueous solution consisting of 1.2 parts of dimethylethanolamine, 1.14 parts of dimethylethanolamine, and 12 parts of deionized water, and
Continuously stir for 1 minute to obtain a particle size of 128 nm and a softening temperature of 70 nm.
A fine resin dispersion with a non-volatile content of 35% was obtained. Production example 6 Nisseki polybutadiene B-2000 (number average molecular weight
2000, 1,2-bonds 65%) was epoxidized using peracetic acid to produce epoxidized polybutadiene with an oxysilane oxygen content of 6.4%. After charging 1000 g of this epoxidized polybutadiene and 354 g of ethyl cellosolve into two autoclaves, 62.1 g of dimethylamine was added, and the mixture was heated to 150°C.
The reaction was carried out for 5 hours. After distilling off the unreacted amine, a mixture of 79.3 g of acrylic acid, 7.6 g of hydroquinone, and 26.4 g of ethyl cellosolve was added to 120°C, 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 substance is
85.2 mmol/100g, acid value 10.0 mmol/100
g, and the solid content concentration was 75.0% by weight. Production example 7 Bisphenol type epoxy resin with an epoxy equivalent of 950 (trade name Epicote 1004 manufactured by Yuka Ciel Epoxy Co., Ltd.) 1000 g dissolved in 343 g of ethyl cellosolve, 76.3 g of acrylic acid, and 10 g of hydroquinone.
and 5g of N,N-dimethylaminoethanol
The resin solution (B) was synthesized by heating to 100°C and reacting for 5 hours. Solid content concentration 75% by weight Production example 8 Nisseki polybutadiene B-1000 (number average molecular weight
1000, 1,2 bonds 60%) 1000g, maleic anhydride
265.8 g, xylene 10 g, and Antigen 6C (Sumitomo Chemical brand name) 1 g were placed in two separable flasks equipped with a reflux condenser and heated at 190°C under a nitrogen stream for 50 minutes.
Allowed time to react. Next, unreacted maleic anhydride and xylene were distilled off under reduced pressure, and the acid value was 214 mmol/100.
g of maleated polybutadiene was synthesized. Next, 1000 g of maleated polybutadiene and 212.4 g of ethyl cellosolve were charged into a two-separable flask equipped with a reflux condenser and reacted with stirring at 120° C. for 2 hours to produce a half-esterified product (C) of maleated polybutadiene. Solid content concentration 98% by weight Example 3 400 g of (A) produced in Production Example 6, 240 g of (B) produced in Production Example 7, and 19.2 g of (C) produced in Production Example 8
After mixing until homogeneous, 8.1 g of acetic acid was added and thoroughly stirred to neutralize. 1835 g of deionized water was gradually added to this varnish to obtain an emulsion with a solids concentration of about 20%. Thereafter, 200 g of the fine resin dispersion of Production Example 5 was added to prepare an aqueous solution having a solid content concentration of approximately 20% (solid content of fine resin particles in the paint bath was approximately 3%). Using the above electrodeposition coating liquid, cathode deposition type electrodeposition coating was performed at 150V using a carbon electrode as an anode and a zinc phosphate treated plate as a cathode. Thereafter, the surface of the object to be coated was washed with water and baked in a baking oven at 175°C for 30 minutes to obtain a coated plate with a film thickness of 20μ. The test results are shown in Table-1. Production example 9 E1800-6.5 (manufactured by Nippon Oil Co., Ltd., epoxidized polybutadiene) 1000 g Butyl cellosolve 349 g Dimethylamine 46 g 50% lactic acid 138 g Deionized water 473 g Phenyl glycidyl ether 117 g Epoxidized polybutadiene E1800-6.5 and butyl cellosolve were charged into an autoclave. rear,
Dimethylamine was added and reacted at 150°C for 5 hours.
After distilling off the unreacted amine, it was cooled to 60°C and heated to 50°C.
at 80 °C after adding a mixture of % lactic acid and deionized water.
Stir and keep warm for 30 minutes. After that, phenyl glycidyl ether was added, the temperature was raised to 110℃, and while stirring and keeping warm, the acetic acid value of the contents was measured by the usual method using phenolphthalene as an indicator and alcoholic KOH as the standard solution, and the acid value was 0.1. The reaction is allowed to proceed until the following is confirmed, and then the production is terminated. Non-volatile content 55% Production example 10 Production example 9 varnish 231g Deionized 315g Carbon black 16g Titanium oxide 92g Kaolin 220g Basic lead silicate 58g After adding deionized water to the varnish of Production Example 9 and dissolving it, add the pigment and use a disper to approx. Stir and mix for 1 hour. After glass beads are added to this mixture, they are dispersed in a sand mill to a particle size of 20 μm or less, and the production is completed after the glass beads are separated. Non-volatile content 55% Example 4 After mixing 40 g of (A) produced in Production Example 6, 240 g of (B) produced in Production Example 7, and 19.2 g of (C) produced in Production Example 8 until uniform, acetic acid was added. 8.1g was thoroughly stirred and neutralized. 1835 g of deionized water was gradually added to this varnish to obtain an emulsion with a solids concentration of about 20%. After that, the pigment paste 360 of Production Example 10
g, 550 g of deionized water, and 260 g of the fine resin particle dispersion of Production Example 5 were uniformly stirred to prepare an enamel electrodeposition bath (the solid content of fine resin particles in the paint was about 2%). Using this electrodeposition bath, the performance of the coating film electrodeposited (200V) and cured under the same conditions as in Example 3 is shown in Table-1.
Shown below. Comparative Example 1 The same procedure as in Example 1 was carried out except that 60 g of the fine resin particles of Production Example 3 were not added and 707 g of deionized water was changed to 662 g. However, the painting voltage
100V Comparative Example 2 The same procedure as in Example 1 was carried out except that 80 g of the fine resin particles of Production Example 3 were not added and 707 g of deionized water was changed to 662 g. However, the painting voltage
150V Comparative Example 3 The same procedure as in Example 3 was carried out except that 200 g of the fine resin particles of Production Example 5 were not added and 1835 g of deionized water was changed to 1800 g. Comparative Example 4 The same procedure as in Example 4 was carried out except that 260 g of the fine resin particles of Production Example 5 were not added and 1835 g of deionized water was changed to 1800 g.

[Table] (1) Throwing property measuring method Reagents/equipment a. DC power supply b. Electrodeposition bath (stainless steel container with inner diameter of 100 mm and depth of 300 mm) c. Stirring device (magnetic stirrer Kg and rotor) d. Stopwatch e. Object to be coated Stand and thermometer (50℃ or 100℃
℃） f The front was also treated according to the painting specifications (length 310mm, width 16mm, wall thickness 0.3mm or 0.8mm)
Steel plate (strip) g Steel pipe tube (inner diameter 17.5mm, length 330mm
mm) Test method a. Adjust the test paint to 30±1℃. b Place the electrocoating tank containing the test paint on top of the magnetic stirrer, insert the rotor and gradually increase the stirring speed until a swirl appears in the center of the paint. c Insert the strip into the tube and secure it in the holder. The lower end of the strip shall be flush with the end of the tube. d Strips and tubes are 254mm in the paint.
Soak. e Connect the anode (+) lead from the power supply to the anion, and the cathode (-) lead to the strip or tube.
[For cations, use this reaction] Attach the lead to the tank. f Check in advance to electrodeposit a film thickness of 20μ, and raise the voltage to the specified voltage over 30 seconds under the specified electrodeposition conditions. g. Raise the strip and tube from the tank, separate the strip and tube, and check the throwing power of the strip using the method specified below. Wash the tube with a suitable solvent and prepare it for next use. h The strips shall be washed with water and baked under the specified conditions. Lightly rub the feather-like thin part at the top of the baked coating on the strip with an eraser, measure the length of the remaining coating, and record it as the throwing power. Average value for front and back. (2) Salt spray resistance: 1/1 of the maximum rust width from the cut part applied to the paint film.
Judgment based on 2 (5% NaCl aqueous solution spray) 〇: 3 mm or less, △: 3 to 5 mm, ×: 5 mm or more

Claims (1)

[Scope of Claims] 1 (a) an aqueous dispersion of an aqueous resin that can be electrodeposited; (b) a softened particle having a particle size of 0.2 to 20 μ and uniformly dispersed in the aqueous dispersion of the aqueous resin; 1. An electrodeposition coating composition comprising, as an essential component, fine resin particles whose temperature is 10° C. or more higher than the temperature of an electrodeposition bath liquid. 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 2, wherein the particle size of the fine resin particles is larger than the particle size of the aqueous resin emulsion. 4 The aqueous resin has a cationic group.
The electrodeposition coating composition according to item 1, 2 or 3. 5 The aqueous resin has a first aqueous resin having an anionic group.
The electrodeposition coating composition according to item 1, 2 or 3. 6 Items 1 to 5, wherein the amount of the fine resin particles is 1 to 50% by weight of the solid content of the aqueous resin.
The electrodeposition coating composition according to any one of paragraphs.