JPH06287483A - Cationic electrodeposition coating compound composition and its production - Google Patents

Abstract

PURPOSE:To obtain the subject composition providing a coating film having excellent smoothness and edge covering properties by adding a specific component to a dispersion resin during dispersion of pigment into the dispersion resin to give a pigment-dispersed taste, blending the paste with a cationic electrodeposition resin emulsion. CONSTITUTION:First, an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane is mixed with pigment and a dispersing resin and dispersed to give a pigment-dispersed resin. Then the paste is blended with a cationic electrodeposition resin emulsion to give the objective composition. The epoxy resin- amine adduct containing a hydrolyzable alkoxysilane, for example, is obtained by reacting diglycidyl ether of bisphenol A with bisphenol A and diethanolamine and reacting the reaction solution with gamma-aminopropyltriethoxysilane and diethanolamine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cationic electrodeposition coating composition, and more particularly to a method of dispersing an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group in a dispersion resin. The present invention relates to a cationic electrodeposition coating composition containing a pigment-dispersed paste prepared by adding it, which is particularly excellent in smoothness and can form a thick coating film even on edge portions such as corners and protrusions.

[0002]

2. Description of the Related Art Cationic electrodeposition coatings, which are widely used mainly in the automobile industry, have excellent anticorrosion properties by themselves, but the coating film does not become thick at the edges of the object to be coated. There is a drawback that the covering property is inferior, and improvement thereof is desired. Therefore, conventionally, various methods for imparting rheology controllability by adding gelled fine particles to a cationic electrodeposition coating have been proposed, and the present applicant has previously proposed that an alkoxysilane group and a hydroxyl group and a cationic group be added. An internally crosslinked gelled fine particle polymer having the same and a method for producing the same have been proposed (see Japanese Patent Laid-Open No. 2-47173).
Further, an internally crosslinked gelled fine particle polymer having an alkoxysilane group, a urethane bond, a hydroxyl group and a cationic group and a method for producing the same have also been proposed (see JP-A-3-62860). The internally crosslinked gelled fine particle polymers proposed above have a cationic electrodeposition property, and even when added to a cationic electrodeposition coating, the bath stability and electrodeposition characteristics are not impaired, and the baked coating film Has a particularly excellent edge covering property, but since it is based on an acrylic resin, it has a drawback that it is slightly inferior in general anticorrosion property, and is still insufficient in practical use.

On the other hand, gelled fine particles using an epoxy resin, which is excellent in terms of anticorrosion property, have been conventionally known. For example, a cationic microgel dispersion in which a mixture of a cationic polyepoxide-amine reaction product and a polyepoxide crosslinking agent is dispersed in water and crosslinked in a particle (Japanese Patent Laid-Open No. 4-226).
No. 171) has been proposed, but since the dispersion is inferior in rheology controllability, it is necessary to use a large amount in order to impart sufficient edge cover property, but if the amount used becomes large. However, there is a drawback that the smoothness of the coated surface is impaired.

[0004]

[Means for Solving the Problems]
As a result of intensive research to develop a rheology control agent that is superior to the conventional gelled fine particles in corrosion resistance and smoothness of the coating film and is useful in cationic electrodeposition coatings,
At the time of dispersing the pigment used for the cationic electrodeposition coating, an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group is used, and this is added to a pigment and a dispersing resin to disperse and mix to prepare a pigment dispersion paste, When this pigment-dispersed paste is mixed with a cationic electrodeposition resin emulsion or the like, the resulting cationic electrodeposition coating composition has a bath stability, electrodeposition characteristics, water resistance of the coating film, and corrosion resistance without being impaired. In order to complete the present invention, it was found that a decrease in melt coating film viscosity during bake-curing of an electrodeposition coating film is controlled to give a cationic electrodeposition coating film having both excellent coating surface smoothness and edge covering property. I arrived.

Thus, the present invention provides a cationic electrodeposition coating composition comprising a pigment-dispersed paste containing an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group. To do.

Further, in the present invention, an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group is added to a pigment and a dispersion resin and dispersed and mixed to prepare a pigment dispersion paste. A method for preparing a cationic electrodeposition coating composition, which comprises mixing with an adhesive resin emulsion.

In the present invention, the epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group, which is added when the pigment dispersion paste is prepared, is adsorbed on the pigment surface together with the dispersing resin, and the resin adsorbed on the pigment surface is When the coating film is baked, the silanol group produced by hydrolysis of the alkoxysilane group in the resin is condensed with the silanol group and / or the hydroxyl group in the case where the hydroxyl group is present, before being thermally fluidized. It is considered that a reaction occurs to exert rheology controllability, that is, the pigment acts as if it were a rheology control agent having a gel layer formed on the surface.

Therefore, by incorporating this pigment-dispersed paste into a cationic electrodeposition coating composition, rheology controllability can be achieved with a smaller amount of resin than the conventional amount of gelled fine particles used.

In the present invention, the "epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group" is
A silanol group stably dispersed in water having a cationic group, particularly an amino group which can be neutralized with an acid as a water-dispersing group, and a silanol group formed by hydrolysis of the alkoxysilane group are silanol groups and a hydroxyl group. Means an adduct capable of condensing with its hydroxyl group, if present.

The above-mentioned epoxy resin-amine adducts include polyamine resins which are usually used in cationic electrodeposition paints. For example, (i) polyepoxide compounds and primary mono- and polyamines, secondary mono- and polyamines. Or an adduct of a mixed primary and secondary polyamine (see, for example, US Pat. No. 3,984,299); (ii) a polyepoxide compound and a secondary mono- and polyamine having a ketiminated primary amino group. Adducts (see, for example, U.S. Pat. No. 4,017,438); (iii) polyepoxide compounds and ketiminated 1
Examples thereof include a reaction product obtained by etherification with a hydroxy compound having a primary amino group (see, for example, JP-A-59-43013).

The polyepoxide compound used for producing the polyamine resin is an epoxy group.

[0012]

[Chemical 1] Suitable are compounds having two or more in one molecule, and generally having a number average molecular weight in the range of at least 200, preferably 400 to 4,000, more preferably 800 to 2,000, and particularly polyphenols. Those obtained by the reaction of the compound with epichlorohydrin are preferred. Examples of the polyphenol compound that can be used for forming the polyepoxide compound include, for example, bis (4-
Hydroxyphenyl) -2,2-propane, 4,4'-
Dihydroxybenzophenone, bis (4-hydroxyphenyl) -1,1-ethane, bis- (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,2 -Propane,
Bis (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, bis (2,4-dihydroxyphenyl) methane, tetra (4-hydroxyphenyl)-
1,1,2,2-ethane, 4,4'-dihydroxydiphenyl sulfone, phenol novolac, cresol novolac and the like can be mentioned.

The polyepoxide compound may be partially reacted with, for example, a polyol, a polyether polyol, a polyester polyol, a polyacid amine, a polycarboxylic acid or a polyisocyanate compound, and further, ε-caprolactone, It may be one obtained by graft-polymerizing an acrylic monomer or the like.

The method of introducing the hydrolyzable alkoxysilane group into the above-mentioned epoxy resin-amine adduct is not particularly limited, and the kind of the hydrolyzable alkoxysilane group to be introduced by a method known per se. However, it is preferable to employ a method that does not produce by-products such as water-soluble salts that adversely affect the electrodeposition coating. For example, the following method can be exemplified.

(1) Method for adding an alkoxysilane group-containing amine compound to an epoxy group in a base resin: Examples of amine compounds that can be used here include those represented by the following formula.

[0016]

[Chemical 2]

(2) Method of adding an alkoxysilane group-containing mercaptan to an epoxy group in a base resin: Examples of the mercaptan that can be used here include the following.

[0018]

[Chemical 3] (3) Method of adding alkoxysilane group-containing epoxy compound to amino group in base resin: Examples of epoxy compounds that can be used here include those of the following formulae.

[0019]

[Chemical 4]

(4) Method for adding an alkoxysilane group-containing isocyanate compound to the hydroxyl group and amino group in the base resin: Examples of the isocyanate compound that can be used here include those of the following formula.

[0021]

[Chemical 5]

In the above formulas, R may be exemplified as follows:

[0023]

Embedded image _{(i) -CH 3, -C 2} H 5, -C 3 H 7, -C 4 H
_9, an alcohol residue such as _{-C 6 H 13, -C 8 H} 17;

[0024]

Embedded image _{(ii) -C 2 H 4 OCH} 3, -C 2 H 4 OC
_{2 H 5, -C 2 H 4} OC 3 H 7, -C 2 H 4 OC 4 H 9, -C 3 H 6
_{OCH 3, -C 3 H 6 OC} 2 H 5, -C 4 H 8 OCH 3, -C 2
_{H 4 OC 2 H 4 OCH 3} , -C 2 H 4 OC 2 H 4 OC 2 H 5, -C
Ether alcohol residue such as ₂ H ₄ OC ₂ H ₄ OC ₄ H ₉ ;

[0025]

[Chemical 8]

[0026]

[Chemical 9]

[0027]

[Chemical 10]

[0028]

[Chemical 11]

Although R in the above formula has a smaller number of carbon atoms, it is more likely to be hydrolyzed, but it is more likely to be condensed after hydrolysis and is less stable in an aqueous system, so that a carbon number of about 2 to 7 is advantageous in terms of balance. . Further, those having 2 or less carbon atoms and those having more than 7 carbon atoms may be combined and balanced.

The amount of the hydrolyzable alkoxysilane group introduced into the epoxy resin-amine adduct as described above is not particularly limited, but is usually the alkoxysilane equivalent (converted per alkoxysilane group. Molecular weight)
Is 500 to 200,000, preferably 1,000 to 4
10,000, more preferably 2,000 to 20,000
It is appropriate to select it within the range of 0.

In the present invention, the epoxy resin amine adduct containing the above-mentioned hydrolyzable alkoxysilane group is added at the time of dispersing the pigment, and is dispersed and mixed with the pigment and the dispersing resin to produce a pigment dispersion paste. You can
These dispersions can be performed by a conventionally known method,
Specifically, a pigment, a dispersing resin, an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group, and a coating additive such as a neutralizing agent, if necessary, and a dispersion mixer such as a ball mill. It is possible to prepare a paste-like product by carrying out a dispersion treatment in it.

As the above-mentioned pigments, any pigment can be used without particular limitation as long as it is a pigment usually used in electrodeposition paints. Examples thereof include titanium white, carbon black, red iron oxide,
Coloring pigments such as yellow lead; extender pigments such as talc, clay, mica, calcium carbonate, silica, barita; strontium chromate, zinc chromate, basic lead silicate,
Examples include rust preventive pigments such as lead chromate.

As the above-mentioned dispersing resin, those listed below as the base resin component for the cationic electrodeposition coating composition can be used. Particularly, they are epoxy-type tertiary amine type, epoxy-type quaternary ammonium salt type, It is suitable to use as an acrylic quaternary ammonium salt type resin.

The amount of the epoxy resin amine adduct containing a hydrolyzable alkoxysilane group added during the production of the pigment dispersion paste is 1 to 35% by weight, preferably 2% by weight based on the total resin solid content in the electrodeposition coating composition. It is desirable to adjust the content to be within the range of 15% by weight. When the added amount is less than 1% by weight, the effect of controlling the decrease in the melt viscosity of the coating film during baking of the electrodeposition coating film is small, and the edge covering property of the electrodeposition coating film tends to be insufficient. If it exceeds, the smoothness of the electrodeposition coating film tends to be poor.

According to the present invention, there is provided a cationic electrodeposition coating composition containing the pigment-dispersed paste produced as described above. In the cationic electrodeposition coating composition, the components other than the pigment-dispersed paste are not particularly limited, and may be the same as those in a normal cationic electrodeposition coating composition.

The cationic electrodeposition coating composition of the present invention comprises, as a base resin component, a resin usually used in a cationic electrodeposition coating, for example, a polyamine resin represented by an amine-added epoxy resin, such as the above-mentioned hydrolyzable alkoxy. Epoxy resin-amine adducts as described in the description of epoxy resin-amine adducts containing silane groups may be included.

Further, when good weather resistance is required for the cured coating film formed using the composition of the present invention,
The amino group-containing acrylic resin or the nonionic acrylic resin having excellent weather resistance is used alone, or it is convenient to use it together with the amine-added epoxy resin.

The amine-added epoxy resin described above can be cured by using a polyisocyanate compound blocked with an alcohol or the like, if necessary.

An amine-added epoxy resin which can be cured without using a blocked isocyanate compound can also be used. For example, a resin obtained by introducing a β-hydroxyalkyl carbamate group into a polyepoxide material (for example, JP-A-59). No. 155470); resins of a type that can be cured by a transesterification reaction (see, for example, JP-A-55-80436) can also be used.

The above-mentioned cationic aqueous solution or dispersion of the cationic electrodeposition coating resin is usually prepared by neutralizing the resin with a water-soluble organic acid such as formic acid, acetic acid or lactic acid.
It can be carried out by water dispersion treatment, and a cationic electrodeposition resin emulsion can be obtained from this.

The cationic electrodeposition coating composition of the present invention can be prepared by mixing the above cationic electrodeposition resin emulsion with the above pigment dispersion paste. If necessary, the cationic electrodeposition coating composition of the present invention may be mixed with coating additives such as an organic solvent, a curing catalyst, a pigment dispersant and a coating surface conditioner.

The cationic electrodeposition coating composition of the present invention can be applied to a desired substrate surface by cationic electrodeposition coating. Cationic electrodeposition coating is carried out according to a method known per se, generally by diluting it with deionized water or the like so that the solid content concentration becomes about 5 to 40% by weight, and further adjusting the pH to 5.5.
The electrodeposition bath comprising the cationic electrodeposition coating composition of the present invention adjusted to within the range of 8.0 is usually adjusted to a bath temperature of 15 to 35 ° C., and the object to be coated is cathodically under a load voltage of 100 to 400 V. Can be done as

The film thickness of the electrodeposition coating which can be formed using the coating composition of the present invention is not particularly limited, but it is generally preferably in the range of 10 to 40 μm based on the cured coating film. The baking temperature of the coating film is generally 100 to 2
A range of 00 ° C is suitable.

[0044]

According to the present invention, a pigment-dispersed paste containing an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group is admixed with a cationic electrodeposition coating composition to be adsorbed on the pigment. The resin functions as a flow control agent during baking of the electrodeposition coating film, and exerts an excellent cratering prevention effect, surface smoothness, edge covering effect, and the like. It is considered that the reason why the above effects are obtained in the present invention is that the cross-linking reaction takes place before the resin adsorbed to the pigment is thermally fluidized during baking of the electrodeposition coating film, and the decrease in melt viscosity can be controlled.

The cationic electrodeposition coating composition of the present invention has good bath stability and electrodeposition characteristics, and can suppress the decrease in the viscosity of the coating film during heat curing, resulting in excellent edge covering properties, It is possible to improve the rustproof property of the part and to form a coating film having a good smoothness of the coated surface.

[0046]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, "part" and "%" indicate "part by weight" and "% by weight", respectively.

Containing Hydrolyzable Alkoxysilane Group
Production of Epoxy Resin Amine Adduct Production Example 1 An epoxy resin amine adduct containing a hydrolyzable alkoxysilane group is produced with the following formulation.

Raw material parts by weight Epon 828EL ¹⁾ 1045 bisphenol A 171 diethanolamine 52.2 KBE-903 ²⁾ 221 diethanolamine 157.5 ethylene glycol monobutyl ether 706 Note 1) Diglycidyl ether of bisphenol A having an epoxy equivalent of about 190 (oil) Chemical Shell Co., Ltd.) Note 2) γ-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) While blowing nitrogen gas into a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas blowing port. And Epon 8
28 EL, bisphenol A and diethanolamine are charged and heated to 120 ° C. and reacted until the epoxy equivalent ³⁾ reaches the theoretical value (317). Then cool to 80 ° C., add KBE-903 and diethanolamine,
The reaction is continued until the tertiary amine value ⁴⁾ reaches the theoretical value (102). Then, the mixture was diluted with ethylene glycol monobutyl ether to obtain an ethylene glycol monobutyl ether solution (I) having a solid content of 70% of an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group having a number average molecular weight of about 1650.

Note 3) According to JIS K-7236. However, the amino group is also added as an epoxy group.

Note 4) After acetylation with acetic anhydride, titration with perchloric acid using crystal violet as an indicator.

Production Example 2 An epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group is produced with the following formulation.

Raw material parts by weight Epon 828EL 950 Bisphenol A 342 Amine A ⁶⁾ 96.5 Amine A (post-added) 193 Amine B ⁷⁾ 159 Deionized water 36 KBE-4028 ⁾ 496 Ethylene glycol monobutyl ether 486 Note 6) Effective A methyl isobutyl ketone solution of ketimine with 74% monoethanolamine and methyl isobutyl ketone.

Note 7) Methyl isobutyl ketone solution of diethylenetriamine diketimine of 84% active ingredient in methyl isobutyl ketone.

Note 8) γ-glycidoxypropylmethyldiethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) Epon 828EL, bisphenol A and amine A were charged into a reactor similar to that of Production Example 1 under nitrogen gas blowing to prepare 160 Heated to ℃, Epoxy equivalent is theoretical value (694)
React until it reaches. Then, the mixture is cooled to 100 ° C., amine A and amine B are added, and the reaction is continued until the tertiary amine value reaches the theoretical value (97). After that, 100 ℃
Then, deionized water is added to carry out a deketiminization reaction, and then KBE-402 is added at 100 ° C. to react until the epoxy group disappears. Then diluted with ethylene glycol monobutyl ether to give a number average molecular weight of about 19
A solution (II) having a solid content of 70% of an epoxy resin amine adduct containing a hydrolyzable alkoxysilane group of 00 was obtained.

Production of Pigment Dispersion Paste Each of the compounding ingredients shown in Table 1 below was added to a ball mill and dispersed for 40 hours to obtain pigment pastes A to D having a solid content of 43%. In the table, the compounding amount of the resin is shown in solid content.

[0056]

[Table 1]

Production Example 1 of Cationic Electrodeposition Coating Composition 157 parts of a cationic emulsion for cationic electrodeposition (manufactured by Kansai Paint Co., Ltd., Electron 9450) having a solid content of 35% and comprising a polyamide-modified epoxy resin and a completely blocked diisocyanate were added , 43% solid content obtained above
153.5 parts of Pigment Paste A of 1. was added with stirring and diluted with 605.4 parts of deionized water to obtain a cationic electrodeposition coating composition.

Examples 2 and 3 and Comparative Example 1 A cationic electrodeposition coating composition was obtained in the same manner as in Example 1 except that the pigment pastes B, C and D were used as the pigment pastes.

Example 4 626 parts of a cation electrocoating clear emulsion (Kansai Paint Co., Ltd., Elektron 9600) having a solid content of 32% and comprising a polyester-modified epoxy resin, a completely blocked diisocyanate and a nonionic acrylic resin, was added to the above. Pigment paste A153.
5 parts was added with stirring and diluted with 552 parts of deionized water to obtain a cationic electrodeposition coating composition.

Examples 5 and 6 and Comparative Example 2 Cationic electrodeposition paints were obtained in the same manner as in Example 4, except that the pigment pastes B, C and D were used as the pigment pastes.

Test Example (Electrodeposition Coating Test) In the cationic electrodeposition paints obtained in Examples 1 to 6 and Comparative Examples 1 and 2, Pearl Bond # 3030 [Nihon Parkerizing Co., Ltd., zinc phosphate type] was used. Chemical conversion treated 0.8 × 3
A cold rolled dull steel plate of 00 × 90 mm (the angle between the end face and the flat portion was 45 degrees) was dipped, and electrodeposition coating was performed using the cold rolled dull steel plate as a cathode. The electrodeposition coating conditions are: electrodeposition coating bath temperature 30 ° C, pH
An electrodeposition coating film having a film thickness (based on the dry film thickness) of 20 μm and a voltage of 6.5 V was formed, washed with water after electrodeposition, and baked at 185 ° C. for 20 minutes. The performance test results of this coated plate are shown in Table 1 below. The measurement results of the coating solution viscosity are also shown in Table-1.

Performance Test Method (* 1) Melt Viscosity of Coating Film The melt viscosity of the electrodeposited coating film at the time of baking is determined by the ball-ball type viscosity measurement method (JIS
-Z-0237), and evaluated from the heat flow appearance of scratches. The numerical value indicates the lowest viscosity (centipoise).

(* 2) End face coverage A test plate is prepared by electrodeposition coating on a steel plate having an edge angle of 45 ° under the condition that the cured film thickness of the flat part is 20 μm and curing under a predetermined baking condition. . Set it on the salt spray device so that the edge of the test plate is vertical, then JIS-Z
The corrosion resistance of the edge portion after 168 hours is evaluated by the −2371 salt water humming test.

⊚: No rust was generated ◯: Slight rust was generated x: Significant rust was generated (* 3) Smoothness of coated surface The finish of the electrodeposited coated surface is visually evaluated.

⊚: Good ∘: Almost good Δ: Slightly bad (* 4) Impact resistance Performed in an atmosphere of 20 ° C. according to JIS-K-5400 8.3.2-1990 method. Weight 500g,
The maximum height (cm) that does not cause coating film damage is shown under the condition that the tip radius of the impact is 1/2 inch. The maximum value was 50 cm.

(* 5) Chipping resistance A bake electrodeposition coated plate is further coated with a thermosetting intermediate coating material and a top coating material, and the following test is carried out on the heat cured material.

Test equipment: Q-G-R Graperometer (Q panel company product) Stone to be sprayed: Crushed stone having a diameter of about 15 to 20 m / m Volume of stone to be sprayed: about 500 ml Spraying air pressure: about 4 kg / Cm ² test temperature: Approx. 20 ° C The test piece is mounted on a test piece holder, and about 500 ml of crushed stone is ejected to the test piece with a blowing air pressure of about 4 kg / cm ² , and then the coated surface state is changed. evaluated. The state of the coated surface is visually observed and evaluated according to the following criteria.

(Evaluation) ⊚ (Good): Slight scratches were observed on a part of the top coating film, and peeling of the electrodeposition coating film was not observed at all.

◯ (Slightly bad): Scratches due to impact are observed in the top coat and intermediate coat, and slight peeling of the electrodeposition coating is observed.

Δ (Poor): Many scratches due to impact were observed on the top coat and the intermediate coat, and peeling of the electrodeposition coat was considerably observed.

(* 6) Secondary adhesion in warm water immersion JIS-K-540 after immersion in 40 ° C. water for 20 days
According to No. 08.5.2-1990, a coating pattern is formed on the coating film, an adhesive cellophane tape is adhered to the surface, and the coated surface after the rapid peeling is evaluated.

◎: Good without any abnormality △: Slight edge peeling of goggles ×: A part of goggles got peeled off (* 7) Salt spray resistance Crossing the electrodeposition coating film with a knife to reach the substrate Put a cut scratch and put it in 100 by JIS-Z-2371.
A salt spray test is performed for 0 hours to measure rust from knife scratches and blister width.

(* 8) 2-Coat Weather Resistance Amino-alkyd resin type paint Amiratukukuria (manufactured by Kansai Paint Co., Ltd.) was further coated on the electrodeposition coated plate for baking by 35 μm and baked at 140 ° C. for 15 minutes. This coated plate was put on a Sunshine Weatherometer for 20 hours and placed in water at 40 ° C for 2 hours.
After soaking for 0 hour, a cross cut is put on the coated plate and a peeling test is performed with a cellophane adhesive tape. This test was repeated to examine the time when peeling occurred.

[0074]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Nagaoka 4-17-1, Higashihachiman, Hiratsuka City, Kanagawa Kansai Paint Co., Ltd.

Claims (3)

[Claims] 1. A cationic electrodeposition coating composition comprising a pigment-dispersed paste containing an epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group. 2. The content of the epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group is in the range of 1 to 35% by weight based on the total resin solid content in the coating composition. Cationic electrodeposition coating composition. 3. An epoxy resin-amine adduct containing a hydrolyzable alkoxysilane group is added to a pigment and a dispersion resin and dispersed and mixed to prepare a pigment dispersion paste. The pigment dispersion paste is a cationic electrodeposition resin. A method for preparing a cationic electrodeposition coating composition, which comprises mixing with an emulsion.