JPH0782340A - Epoxy resin composition and electrodeposition coating composition - Google Patents

Abstract

(57) [Summary] [Objective] An electrodeposition coating composition capable of forming a coating film having excellent flexibility, excellent adhesion to a substrate, excellent impact resistance, particularly excellent chipping resistance, and excellent corrosion resistance. And an epoxy resin composition as a raw material for producing the same. [Structure] (A) diglycidyl ether of polyalkylene oxide, (B) carboxylic acid terminated butadiene-acrylonitrile copolymer, (C) epoxy resin, (D)
An epoxy resin composition obtained by reacting a bifunctional phenol compound and an electrodeposition coating composition using the same as a raw material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in flexibility, adhesion to a substrate, good impact resistance, particularly chipping resistance,
The present invention also relates to an electrodeposition coating composition capable of forming a coating film having excellent corrosion resistance, and an epoxy resin composition as a raw material for producing the same.

[0002]

BACKGROUND OF THE INVENTION Epoxy resins are widely used in paints, adhesives, IC encapsulants, etc. because they form strong three-dimensional crosslinks using amines, acid anhydrides, etc. as curing agents. In particular, it is widely used as an anticorrosion paint for paints because of its excellent corrosion resistance. Particularly in recent years, cationic electrodeposition paints that neutralize the epoxy resin amine adduct with an acid to make it water-soluble or water-disperse and cure with blocked polyisocyanate are used for automobile bodies, parts, home appliances, steel furniture, building materials, and construction. It is widely used in equipment to take advantage of its high anticorrosive power.

[0003]

However, since the epoxy resin produces a large internal stress when it is crosslinked by three-dimensional crosslinking and has a high glass transition temperature, it is very brittle at room temperature or below. It becomes a film. Therefore, when such an epoxy resin-containing electrodeposition coating is applied to an automobile body, the coating film is likely to be cracked or peeled off due to sand, pebbles, etc. that collide with the vehicle body while the automobile is running. Also, it is strongly required to improve the resistance (chipping resistance) to these colliding objects. Conventionally, in order to improve chipping resistance, improvements utilizing various flexible components have been proposed. For example, Japanese Patent Publication No. 56-41670,
JP-A-1-25473, which uses a butadiene-acrylonitrile copolymer as in JP-A-3-504396.
As described in 2, there may be mentioned one using urethane diol for chain extension of the epoxy resin. However, although they have the effect of improving the flexibility of the coating film, they have a problem in the stability of the electrodeposition coating composition, and thus they have problems that precipitation easily occurs during storage or the corrosion resistance decreases. It was

[0004]

The inventors of the present invention have earnestly studied, and as a result, when modifying an epoxy resin with a rubber component such as butadiene-acrylonitrile rubber which imparts flexibility, polyalkylene is partially added to the epoxy resin. By using a diglycidyl ether of oxide, it was found that the flexibility of the coating film is maintained, good chipping resistance is maintained, corrosion resistance is also improved, and stability of the coating is also improved. did.

That is, the present invention comprises (A) a diglycidyl ether of a polyalkylene oxide, (B) a carboxylic acid-terminated butadiene-acrylonitrile copolymer, and (C).
The present invention provides an epoxy resin composition obtained by reacting an epoxy resin with a (D) bifunctional phenol compound, and an electrodeposition coating composition using the same as a raw material.

The diglycidyl ether of the polyalkylene oxide (A) used in the present invention preferably has a substituted or unsubstituted carbon number of 2 to 5 as its alkylene chain.
Having an epoxy equivalent of 1
0 to 500, more preferably 3 carbon atoms
4 to 4, and has an epoxy equivalent of 200 to 400. If its carbon number is less than 2,
The water resistance of the coating film having a strong hydrophilicity is lowered, and if it exceeds 5, the stability is lowered. The epoxy equivalent is 100
If it is less than 500, the stability of the coating composition is reduced, and if it exceeds 500, the water resistance of the coating film is reduced. The proportion of the diglycidyl ether of polyalkylene oxide in the epoxy resin composition of the present invention is preferably 10 to 30% by weight, more preferably 1
It is 5 to 25% by weight. If it is less than 10% by weight, good stability of the electrodeposition coating cannot be obtained, and if it exceeds 30% by weight, the water resistance of the coating film decreases, which is not preferable.

As the diglycidyl ether of polyalkylene oxide (A), for example, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and the like are known and can be easily obtained. For example, Dow Chemical Co., trade name DER-740, Sanyo Kasei Co., trade name PP-300.
P, manufactured by Tohto Kasei Co., Ltd., trade name PG-207, etc.

The carboxylic acid-terminated butadiene-acrylonitrile copolymer (B) used in the present invention preferably has a molecular weight of 1,000 to 5,000 and an acrylonitrile content of 10 to 30% by weight. If the molecular weight is less than 1000, the effect of imparting flexibility cannot be obtained,
On the other hand, when it exceeds 5,000, the viscosity of the obtained epoxy resin becomes high and the handling becomes difficult. When the acrylonitrile content is less than 10% by weight, the compatibility between the butadiene-acrylonitrile copolymer and the epoxy resin is lowered, and the stability when made into a coating is lowered. On the other hand, when it exceeds 30% by weight, the chipping resistance is lowered. The proportion of the carboxylic acid terminated butadiene-acrylonitrile copolymer (B) in the epoxy resin composition of the present invention is preferably 3 to 20% by weight. It is more preferably 5 to 15% by weight. If it is less than 3% by weight, sufficient chipping resistance cannot be obtained, and if it exceeds 20% by weight, the viscosity of the resin becomes high and the workability is deteriorated, which is not preferable.

Such (B) carboxylic acid terminated butadiene-
The acrylonitrile copolymer is B.I. F. Goodrich
It is well known by the trade name Hycar CTBN of the company (US), and various resins are commercially available depending on the molecular weight and the acrylonitrile content. Among them, Hycar C
TBN1300-13 (molecular weight 3200, acrylonitrile content 27% by weight), Hycar CTBN130
0-8 (molecular weight 3600, acrylonitrile content 18
% By weight can be preferably used.

The epoxy resin (C) used in the present invention can be used without any problem as long as it is an epoxy resin usually used for paints, but the epoxy equivalent is 100 to 1000, preferably 150 to 500, epichlorohydrin-bisphenol A. Mold epoxy resins are preferred. For example,
Made by Shell, trade name Epikote # 828, Do
w Chemical Company, trade name DER331, Sumitomo Chemical Co., trade name Sumiepoxy ELA-128 and the like can be preferably used. In addition, bisphenol F type, bisphenol AD type and alicyclic epoxy resins can be used without any trouble.

As the (D) bifunctional phenol compound used in the present invention, bisphenols such as bisphenol A, bisphenol F and bisphenol AD, and mononuclear compounds such as resorcinol and hydroquinone can be preferably used. Further, these bifunctional phenol compounds may be nucleus-substituted with an alkyl group, a halogen, an alkoxy group or the like.

The proportion of (C) the epoxy resin and (D) the bifunctional phenol compound in the present invention is the content of (A) and (B) and the epoxy equivalent required of the epoxy resin composition of the present invention. However, it is desirable that the (C) epoxy resin is 40 to 60% by weight and the (D) bifunctional phenol compound is 20 to 35% by weight.

In the present invention, the above (A),
The epoxy resin composition of the present invention can be obtained by reacting (B), (C) and (D) in the same manner as a reaction with an ordinary epoxy resin, phenolic hydroxyl group and carboxylic acid. At that time, as a catalyst, tertiary amines such as triethylamine, tributylamine, benzyldimethylamine,
It is desirable to use phosphines such as triethylphosphine, tributylphosphine and triphenylphosphine. If necessary, a suitable solvent may be used in the reaction, such as aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and propylene glycol monomethyl ether. It is possible to use various ethers and acetic acid esters of these ethers.

In order to obtain the epoxy resin composition of the present invention, (A) a polyalkylene oxide diglycyl ether and an excess of (D) a bifunctional phenol compound are charged together with a catalyst and, if necessary, a solvent as described above. After reacting at a temperature of 60 to 180 ° C. under normal pressure, a predetermined amount of (B) carboxylic acid-terminated butadiene-acrylonitrile copolymer and (C) epoxy resin are added to obtain the purpose of the epoxy resin composition of the present invention. It is obtained by reacting until the epoxy equivalent is reached. The catalyst in that case is 0.01-1.
It is desirable to use 0% by weight. On the other hand, the epoxy resin composition of the present invention comprises (A), (B), (C) and (D)
It can also be obtained by charging with a catalyst and a solvent and carrying out the reaction under the same conditions as above.

The epoxy resin composition of the present invention has an epoxy equivalent of 500 to 3000, preferably 700.
~ 1500. When the epoxy equivalent is less than 500,
The glass transition temperature of the obtained coating film is low, and a tough coating film cannot be obtained. Further, a resin liquid having an epoxy equivalent of higher than 3000 has a high viscosity and is disadvantageous in handling, and a large amount of solvent is required to reduce the viscosity, which is economically disadvantageous.

In order to obtain an electrodeposition coating composition containing the epoxy resin composition obtained as described above, the epoxy resin composition is reacted with a primary or secondary amine and then acidified with an acid. Watering or water-dispersion is carried out by mixing.
The amine used has 1 active hydrogen that reacts with the epoxy group.
Secondary alkylamines having more than one dimethylamine, diethylamine, dibutylamine, etc., diethanolamine, dipropanolamine, methylethanolamine, ethylethanolamine, methylpropanolamine, etc., secondary alkylalkanolamines, pyrrolidine, piperidine , Cyclic amines such as morpholine and 1-piperazine ethanol can be preferably used. Further, primary amino of polyamine having one secondary amino group in one molecule such as monoethylaminoethylamine, monoethylaminopropylamine, diethylenetriamine, dibutylenetriamine, and having one or more primary amino groups. It is obtained by reacting a group with a ketone such as methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone. Also ketimine compounds can be used. The amount of these amines used is such that the amino group content is 0.3 to 3.0 per 1 g of the resin solid content.
It is set to be millimole, preferably 0.8 to 2.0 millimole. If it is less than 0.3 mmol, it is difficult to make it water-soluble or water-dispersible, and the stability of the coating is insufficient, which is not preferable. On the other hand, if the amount exceeds 3.0 millimoles, dispersibility in water or water solubilization is easy, but during electrodeposition coating, too much current flows to generate a large amount of electrolytic gas, impairing the smoothness of the coating film. .

The acid used to neutralize the epoxy resin reacted with the amine to make it water-soluble or water-dispersible may be either an inorganic acid or an organic acid, such as nitric acid, hydrochloric acid or phosphoric acid. , Sulfuric acid, lactic acid, formic acid, acetic acid, propionic acid, butyric acid and the like can be used. The amount of acid used for neutralization is
20 to 20 in millimoles of acid per 100 g of resin solids
70, preferably 25-40. When the amount of acid is less than 20 in the above unit, sufficient water-solubilization or water dispersibility cannot be obtained, and when it exceeds 70, it is difficult to obtain a sufficient film thickness during electrodeposition coating, and much electrolysis gas is generated. Become.

When the epoxy resin composition of the present invention is water-solubilized or water-dispersed as described above and used for electrodeposition coating as an electrodeposition coating composition, a known curing method used for conventional electrodeposition coating compositions. It is desirable to heat cure with an agent such as urea-formaldehyde resin, melamine resin, aminoplast resin such as benzoguanamine resin or blocked polyisocyanate.
In addition to the above, as a curing agent, European Patent 04086
A β-hydroxyalkyl ester cross-linking agent described in No. 7, a carboalkoxymethyl ester cross-linking agent described in No. 102501, and a urea condensation product described in German Patent Publication No. 3311514 can also be preferably used. Particularly preferably, aromatic diisocyanates such as toluylene diisocyanate and diphenylmethane-4,4′-diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate, and alicyclic diisocyanates such as isophorone diisocyanate are used. A mixture of monomers and / or dimers and trimers, or trimethylolpropane, (poly) ethylene glycol,
Blocked polyisocyanates obtained by blocking a half-block compound of a polyhydroxy compound such as (poly) propylene glycol and these polyisocyanates with alcohols, cellosolves, oximes, caprolactams and the like.

In addition, the electrodeposition coating composition of the present invention contains known resins conventionally used in electrodeposition coating, such as amine-modified epoxy resin and amine-modified polybutadiene resin.
If necessary, an amine-modified polyurethane polyol resin, an amine-modified acrylic resin, etc. can be used together.

In addition, the electrodeposition coating composition of the present invention comprises a known solvent, such as toluene, which has been conventionally used in electrodeposition coatings in order to improve the stability, coating workability, etc. of the coating.
Aromatic hydrocarbons such as xylene, isopropyl alcohol, alcohols such as 2-ethylhexanol,
Ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, monoacetic acid esters of these ethers, and ketones such as methyl ethyl ketone and methyl isobutyl ketone can be used. The amount of these solvents used is not particularly limited, but it is desirable to be as small as possible in consideration of recent air pollution problems.

The electrodeposition coating composition of the present invention is further used in conventional electrodeposition coatings such as surface modifiers, additives such as dispersants, pigments such as titanium oxide and carbon, extender pigments and curing catalysts. Known materials can be contained. In order to perform electrodeposition coating using the electrodeposition coating composition of the present invention, the solid content in the coating bath is adjusted to 5 to 45% by weight, preferably 10 to 30% by weight, and the pH of the bath is adjusted. 4.5 ~
It is adjusted to 8.0, preferably 5.0 to 7.5. The coating is carried out by keeping the bath temperature at 15 to 40 ° C and applying a voltage of 50 to 500 V for 30 to 360 seconds.
These coating conditions do not deviate from the conventionally known and well-known electrodeposition coating conditions. Using the object to be coated as a cathode, electrodeposition coating is performed as described above, followed by washing with water and baking in the usual manner to obtain a coated object. The baking conditions are selected in the range of 80 to 220 ° C depending on the curing agent used, and 3 to 60
Bake for minutes. The epoxy resin composition of the present invention can be used in addition to the electrodeposition coating composition of the present invention containing the epoxy resin composition, in addition to ordinary epoxy hardeners such as amines and epoxy latent hardeners such as dicyandiamide. However, it can be cured and can also be used as a resin for a solvent type two-component epoxy resin coating material or a one-component baking type epoxy coating material.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. (Example 1) (1) PP-300 400 parts by weight (Sanyo Chemical Co., Ltd. polypropylene glycol diglycidyl ether, epoxy equivalent = 300) (2) Bisphenol A 435 parts by weight (3) ELA-128 869 parts by weight (Sumitomo Chemical epoxy liquid epoxy resin, epoxy equivalent = 186) (4) Hycar CTBN1300-13 296 parts by weight (BF Goodrich, carboxylic acid terminated butadiene-acrylonitrile copolymer molecular weight 3200, acrylonitrile content 27% by weight) (5) ) Triphenylphosphine 4 parts by weight (6) Toluene 218 parts by weight were charged with (1), (2) and (5) in a 5 liter 4-necked flask equipped with a cooling tube, a thermometer and a stirrer and stirred. 1
The temperature was raised to 50 ° C. in an oil bath. The reaction was continued at 150 ° C. for 3 hours, and it was confirmed by infrared spectroscopy that the epoxy group had disappeared. Then cool down to 110 ° C,
(3), (4) and (6) were added. The reaction was continued while maintaining the temperature at 120 ° C. to synthesize an epoxy resin composition having an epoxy equivalent of 1000. The temperature was cooled to 100 ° C., and 975 parts by weight of propylene glycol monomethyl ether was added and taken out. The epoxy resin liquid taken out had a solid content of 63%, a viscosity of 100 poise, and contained 14.8% of a butadiene-acrylonitrile copolymer per solid content of the epoxy resin.

Example 2 400 parts by weight of PG-207 (polypropylene glycol diglycidyl ether manufactured by Tohto Kasei Co., epoxy equivalent = 317) 512 parts by weight of bisphenol A Epikote # 828 1027 parts by weight (liquid epoxy resin manufactured by Shell, Epoxy equivalent = 186) Hycar CTBN1300-8 154 parts by weight (BF Goodrich, carboxylic acid terminated butadiene-acrylonitrile copolymer molecular weight 3600, acrylonitrile content 18% by weight) Triphenylphosphine 4 parts by weight Toluene 228 parts by weight The reaction was performed in the same manner as in 1 to obtain an epoxy resin composition having an epoxy equivalent of 980. It was diluted with 658 parts by weight of propylene glycol monomethyl ether in the same manner as in Example 1 and taken out. The resulting resin liquid has a solid content of 70% and a viscosity of 200.
It was a poise and contained 6.8% of a butadiene-acrylonitrile copolymer per epoxy resin solid content.

Example 3 400 parts by weight of PG-207 (polypropylene glycol diglycidyl ether manufactured by Tohto Kasei Co., epoxy equivalent = 317) 477 parts by weight of bisphenol A ELA-128 977 parts by weight (Liquid epoxy resin manufactured by Sumitomo Chemical Co., Ltd.) , Epoxy equivalent = 186) Hycar CTBN1300-13 239 parts by weight (BF Goodrich, carboxylic acid terminated butadiene-acrylonitrile copolymer molecular weight 3200, acrylonitrile content 27% by weight) triphenylphosphine 4 parts by weight toluene 228 parts by weight The reaction was carried out in the same manner as in Example 1 to obtain an epoxy resin composition having an epoxy equivalent of 950. It was diluted with 658 parts by weight of propylene glycol monomethyl ether in the same manner as in Example 1 and taken out. The resulting resin liquid has a solid content of 70% and a viscosity of 400.
Poise, 10.6% per epoxy resin solids
Of butadiene-acrylonitrile copolymer.

Reference Example 1 Hycar CTBN1300-8 290 parts by weight ELA-128 1213 parts by weight Bisphenol A 497 parts by weight Triphenylphosphine 4 parts by weight Toluene 857 parts by weight was charged into a 3 liter flask and treated in the same manner as in Example 1. The reaction was performed to obtain an epoxy resin composition having an epoxy equivalent of 1000. The obtained resin liquid had a solid content of 70% and a viscosity of 300 poise, and contained 14.5% of a butadiene-acrylonitrile copolymer per epoxy resin solid content.

Reference Example 2 Synthetic Example of Resin for Pigment Dispersion ELA-128 670 parts by weight Epikote # 1001 950 parts by weight (Shell's epoxy resin epoxy equivalent 475) Propylene glycol monomethyl ether 811 parts by weight is the same as in Example 1. It was charged in a simple 5 liter flask and dissolved at 100 ° C. After that, the mixture was cooled to 60 ° C., 195 parts by weight of dimethylaminopropylamine and 189 parts by weight of diethanolamine were added, and the mixture was kept at 80 ° C. for 2 hours while paying attention to heat generation, and the tertiary amino group was added at 2.5 mmol / g resin solid content. An amino-modified epoxy resin containing was obtained.

Reference Example 3 Synthesis of Blocked Polyisocyanate Tolylene diisocyanate 522 parts by weight Methyl isobutyl ketone 433 parts by weight was charged in the same 2 liter 4 neck flask as in Example 1 and kept at 40 ° C. with stirring. 354 parts by weight of ethylene glycol monobutyl ether was added dropwise over 1 hour. After the dropping, the mixture was further held at 40 ° C. for 1 hour, 134 parts by weight of trimethylolpropane was added, the temperature was raised to 60 ° C., and stirring was continued. By the titration method, the reaction was continued at 60 ° C. until the residual isocyanate group ratio became 0 to obtain a blocked polyisocyanate having a solid content of 70%.

Reference Example 4 3193 parts by weight of the epoxy resin composition liquid obtained in Example 1 was placed in a 5 liter 4-necked flask similar to Example 1, and 199.5 parts by weight of diethanolamine was added. The reaction is carried out at 100 ° C. for 3 hours with stirring. An amino-modified epoxy resin containing a tertiary amino group of 0.864 mmol / g resin solid content was obtained. The solid content of the resin liquid was 63.8% and the viscosity was 135 poise.

Reference Example 5 2979 parts by weight of the epoxy resin composition liquid obtained in Example 2 213 parts by weight of diethanolamine were reacted in the same manner as in Example 4 to give a tertiary amino group content of 0.867 mmol. Amino-modified epoxy resin containing / g resin solids was obtained. Solid content of resin liquid is 72.2
%, The viscosity was 230 poise.

Reference Example 6 2379 parts by weight of the epoxy resin composition liquid obtained in Example 3 220 parts by weight of diethanolamine were reacted in the same manner as in Example 4 to give a tertiary amino group content of 0.909 mmol. Amino-modified epoxy resin containing / g resin solids was obtained. The solid content of the resin liquid is 72.3.
%, The viscosity was 435 poise.

Reference Example 7 2857 parts by weight of the epoxy resin solution obtained in Reference Example 1 and 200 parts by weight of diethanolamine were reacted in the same manner as in Example 4 to give a tertiary amino group content of 0.864 mmol / g. An amino-modified epoxy resin containing resin solids was obtained. Solid content of resin liquid is 72.0
%, The viscosity was 335 poise.

Reference Example 8 Production of Pigment Dispersion Liquid (1) Amino-modified epoxy resin liquid obtained in Reference Example 2 1406 parts by weight (2) Acetic acid 48 parts by weight (3) Pure water 4203 parts by weight (4) Carbon Black 80 parts by weight (5) Titanium dioxide 2000 parts by weight (6) Aluminum silicate 1500 parts by weight (7) Lead silicate 250 parts by weight (8) Dibutyltin oxide 50 parts by weight (9) Ethylene glycol monobutyl ether 200 parts by weight Total 9737 parts by weight Part (1), (2), and (3) were charged into a clean cylindrical stainless steel container of 10 liters, and the resin was dissolved under stirring. Further, the remaining (4) to (9) were charged and mixed well. Then, the pigment particles were dispersed with a 1.5 liter motor mill (bead type dispersing machine manufactured by Eiger Co., Ltd.) until the particles became 5 μm or less, to obtain a stable pigment dispersion liquid.

(Examples 4 to 6 and Comparative Example 1) Each resin was blended in the same composition as shown in Table 1 with the same amount of 5 liters as in Example 1.
Charge into a two-necked flask, and 50-60m at 90-100 ° C.
A predetermined amount of solvent was removed under reduced pressure of mHg. Then, in a cylindrical stainless steel container charged with a predetermined amount of formic acid and pure water,
With sufficient stirring, the desolvated resin solution was gradually added and emulsified to obtain a resin varnish having a solid content of 35%. Further, the pigment dispersion obtained in Reference Example 8 and pure water were added to this resin varnish to obtain an electrodeposition coating bath having a solid content of 20%. Cathode electrodeposition coating on zinc phosphate treated steel sheet and untreated steel sheet, 1
Baking was performed at 70 ° C. for 20 minutes to obtain a 20 μm coating film. The following various coating film tests were conducted. The test results are shown in Table 2. Various test methods for the coating film will be described below. The numerical values in Table 1 represent parts by weight.

Test method of coating film (1) Chipping resistance test After electrodeposition coating, polyester-melamine type 30 μm intermediate coating baking conditions 140 ° C. 18 minutes Polyester-melamine type top coating 40 μm baking conditions 140 ° C. 18 minutes were applied and tested. did. The chipping test was carried out by a gravure tester under the following conditions. Temperature −20 ° C. Angle of test plate 90 ° Chip No. 6 crushed stone Injection pressure 4 Kg / cm ^{2 For} evaluation, the average diameter of the portion where the crushed stone hit and the coating film peeled off was measured. (2) Stability test of resin varnish 40 times the resin varnish prepared in Examples 4 to 6 and Comparative Example 1
It was kept in a constant temperature bath at ℃ for 2 weeks and the change of the state of the resin dispersion was observed. (3) Salt spray test It was carried out according to JIS K-5400-9-1. However, the width of rust from the cross-cut portion (one side) was evaluated for the untreated steel sheet for 480 hours and for the zinc phosphate steel sheet for 1000 hours.

[0035]

[Table 1]

[0036]

[Table 2]

Note 1 ⊚: No sedimentation and no increase in viscosity X: Sedimentation occurred Note 2 ○: Good Note 3 500 g, 1/2 inch

[0038]

EFFECT OF THE INVENTION The electrodeposition coating composition using the epoxy resin composition of the present invention as a raw material has excellent coating stability, good adhesion to the raw material metal, and good flexibility and chipping resistance. It is possible to provide a high corrosion resistant coating film. Therefore, it can be preferably used in various industrial coating fields, particularly in the automobile industry field.

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Claims (10)

[Claims] 1. A diglycidyl ether of a polyalkylene oxide (A) and a carboxylic acid-terminated butadiene (B).
Acrylonitrile copolymer, (C) epoxy resin,
(D) An epoxy resin composition obtained by reacting with a bifunctional phenol compound. 2. The diglycidyl ether of a polyalkylene oxide of (A) has a substituted or unsubstituted C2 to C5 alkylene chain and has an epoxy equivalent of 100 to 500. 1. The epoxy resin composition of 1. 3. The epoxy resin composition according to claim 1, wherein the carboxylic acid-terminated butadiene-acrylonitrile copolymer (B) has a molecular weight of 1000 to 5000 and an acrylonitrile content of 10 to 30% by weight. 4. The epoxy resin composition according to claim 1, wherein the epoxy resin of (C) has an epoxy equivalent of 100 to 1000. 5. The epoxy resin composition according to claim 1, which has an epoxy equivalent of 500 to 3000. 6. A diglycidyl ether of a polyalkylene oxide (A) and a carboxylic acid-terminated butadiene (B).
Acrylonitrile copolymer, (C) epoxy resin,
(D) an epoxy resin composition obtained by reacting with a bifunctional phenol compound is reacted with a primary or secondary amine,
An electrodeposition coating composition containing an acid-neutralized product. 7. The diglycidyl ether of a polyalkylene oxide of (A) has a substituted or unsubstituted C2 to C5 alkylene chain and has an epoxy equivalent of 100 to 500. 6. The electrodeposition coating composition of 6. 8. The electrodeposition coating composition according to claim 6, wherein the carboxylic acid-terminated butadiene-acrylonitrile copolymer (B) has a molecular weight of 1000 to 5000 and an acrylonitrile content of 10 to 30% by weight. 9. The electrodeposition coating composition according to claim 6, wherein the epoxy equivalent of the epoxy resin (C) is 100 to 1000. 10. The electrodeposition coating composition according to claim 6, wherein the epoxy equivalent of the epoxy resin composition is 500 to 3000.