JP2000290584A - Resin composition for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for coating improved in electrodeposition coating properties and in coated surface smoothness, having a low organic solvent content and free from a lead compound by compounding a specific modified epoxy-polyamine resin, SOLUTION: A diepoxide compound selected from formulae I and II and a bisphenol A type epoxy resin having an epoxy equivalent of 170-500 are reacted with bisphenols to give an epoxy resin having a number average mol.wt. of 800-10,000. This epoxy resin is reacted with a cyclic ester of formula III in the presence of a catalyst at 120-200 deg.C to give a lactone-modified epoxy resin, which is reacted with a reactive hydrogen-containing amine compound in an organic solvent at 30-150 deg.C for 1-5 hr to give a modified epoxy-polyamine resin having a number average mol.wt. of 1,000-20,000 and an amine number of 15-100, which is incorporated into the resin composition. In the formula, R1 is H or a 1-6C alkyl; m and n are each an integer not less than 0; m+n:1-20; X is 1-9; y is 1-50; R2 is H or methyl; and p is 3-6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for coating, and more particularly, to an electrodeposition coating property, a smoothness of a coated surface, and an anticorrosion irrespective of a low organic solvent content and no lead compound. The present invention relates to a resin composition for a cationic electrodeposition paint capable of forming a coating film having excellent properties.

[0002]

2. Description of the Related Art Electrodeposition paints have been used for a wide variety of applications including undercoat paints for automobiles, and those having various properties have been developed. In particular, a cationic electrodeposition paint containing, as a base resin, an epoxy resin containing an amine group as a solubilizing group and an epoxy resin solubilized by a quaternary ammonium base, has excellent corrosion resistance and throwing power. Therefore, it has come to be widely used instead of the conventional anionic electrodeposition paint.

[0003] These cationic electrodeposition paints are generally water-based paints, but are usually used in combination with an organic solvent in order to ensure electrodeposition coatability and smoothness of the coated surface, and to prevent corrosion. Lead compounds are included. The organic solvent plays an important role during the formation of the electrodeposited deposition film, but from the viewpoint of VOC (volatile organic substance), it is desirable to reduce as much as possible.
In addition, lead compounds are very harmful substances, and their use is problematic in terms of pollution control.

[0004]

SUMMARY OF THE INVENTION The main object of the present invention is to provide a coating film which has no drawbacks as described above, has a low organic solvent content and does not contain a lead compound, and has excellent coating properties such as anticorrosion properties and smooth coating surfaces. An object of the present invention is to provide a resin composition for a cationic electrodeposition paint.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems of the cationic electrodeposition coating composition. The inventors have found that the above object can be achieved by using a resin obtained by reacting a cyclic ester as a base resin, and have completed the present invention.

According to the present invention, the following general formulas (I) and (II)

[0007]

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In the formula, R ¹ is a hydrogen atom or a group having 1 to 6 carbon atoms.
M and n are each 0 or more, and the sum of m and n is in the range of 1 to 20, x is an integer of 1 to 9, and y is a number of 1 to 50. The epoxy resin (c) obtained by reacting a diepoxide compound (a) selected from the group consisting of the compounds represented by and a bisphenol A type epoxy resin having an epoxy equivalent of 170 to 500 with a bisphenol (b). And the following general formula (III)

[0009]

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In the formula, R ² represents a hydrogen atom or a methyl group, p is an integer of from 3 to 6, and a cyclic ester (d) is reacted, and the resulting modified epoxy resin (e) is further reacted. And a coating resin composition comprising a modified epoxy-polyamine resin (f) obtained by reacting an amine compound having an active hydrogen.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the coating resin composition of the present invention will be described in more detail.

The diepoxide compound of the formula (I) used as the component (a) in the present invention may be prepared by adding bisphenol A to the following formula (I) according to a method known per se.
V)

[0013]

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In the formula, R ¹ has the above-mentioned meaning, and can be produced by adding an alkylene oxide represented by the above formula, and further reacting the obtained hydroxyl-terminated polyether compound with epihalohydrin for diepoxylation. Examples of the alkylene oxide of the above formula (IV) used herein include alkylene oxides having 2 to 8 carbon atoms such as ethylene oxide, propylene oxide and butylene oxide. Among them, propylene oxide (R ¹ is methyl Compounds of formula (IV)) are preferred.

The number of moles of the alkylene oxide added in the formula (I), that is, the numbers m and n of the repeating units of the alkylene oxide structure portion are each 0 or more, preferably a number in the range of 1 to 10, and n (m +
n) can be a number ranging from 1 to 20, preferably 2 to 10.

The above-mentioned formula (II) as component (a)
According to a method known per se, (i) a hydroxyl-terminated polyalkylene oxide obtained by subjecting the alkylene oxide of the formula (IV) to ring-opening polymerization using an alkylene glycol as an initiator according to a method known per se, Reacting with epihalohydrin to diepoxylate; or (ii) reacting with the following formula (V)

[0017]

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Wherein R ¹ and x have the meanings given above;
Or a polyether diol obtained by dehydrating and condensing two or more of the alkylene glycols represented by the formula (1) with an epihalohydrin to cause diepoxylation.
The alkylene glycol of the formula (V) used herein includes ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6 Alkylene glycols having 2 to 10 carbon atoms, such as -hexanediol and 1,8-octanediol.

In the above formula (V), x can be an integer in the range of 1 to 9, preferably 1 to 6. In the formula (II), the number y of the repeating units of the alkylene oxide or alkylene glycol structure portion may be a number in the range of 1 to 50, preferably 5 to 20.

According to the present invention, the above-described diepoxide compound (a) has an epoxy equivalent of 150 to 50 first.
The epoxy resin (c) is produced by reacting with a bisphenol (b) in combination with a bisphenol A type epoxy resin of No. 0.

The "bisphenol A type epoxy resin having an epoxy equivalent of 170 to 500" which is reacted with the bisphenols (b) in combination with the diepoxide compound (a) is obtained by the reaction of bisphenol A with epihalohydrin. , Typically the following formula (V
I)

[0022]

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In the formula, q is a number within the range of 0 to 5, preferably 0 to 3, and includes a relatively low molecular weight substance having two or more epoxy groups in one molecule. .

The bisphenol A type epoxy resin has the following properties:
Epoxy equivalents in the range of 70 to 500, preferably 200 to 400 and 340 to 1500, preferably 400 to
It may have a number average molecular weight in the range of 1000.

On the other hand, the above-mentioned diepoxide compound (a) and bisphenols (b) reacted with the bisphenol A type epoxy resin include the following general formula (VII):

[0026]

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In the formula, R ³ and R ⁴ each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a trifluoromethyl group, and R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³
Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and specifically includes, for example, bis (4-hydroxyphenyl) -2,2-propane (bisphenol A), (4-hydroxyphenyl) -1,1-ethane, bis (4-hydroxyphenyl) methane (bisphenol F) and the like. Of these, bisphenol A is particularly preferred.

The reaction between the diepoxide compound (a) and the bisphenol A-type epoxy resin with the bisphenols (b) is usually carried out without using a solvent in an atmosphere of an inert gas such as nitrogen gas. Heating to a temperature of about 100 to about 200C, preferably about 120 to about 170C in the presence of a catalyst such as a tertiary amine such as tributylamine; a quaternary ammonium salt such as tetraethylammonium bromide. Can be performed. The reaction is generally performed until the epoxy equivalent of the resulting epoxy resin (c) is in the range of 400 to 5000, especially 500 to 2000.

The proportions of the diepoxide compound (a), the bisphenol A type epoxy resin and the bisphenols (b) in the above reaction are not strictly limited, and may be varied according to the type of these components used. In general, the amount of the diepoxide compound (a) is preferably in the range of 5 to 50% by weight, particularly preferably 10 to 40% by weight, based on the total solid content of the above three components including the same. The ratio of the bisphenol A type epoxy resin to the bisphenol (b) is generally 50 to 95% by weight, especially 60 to 80% by weight, based on the total solid content of these two components.
Weight percent, and bisphenols (b)
-5% by weight, especially 40-20% by weight.

The epoxy resin (c) thus obtained is
Usually, it can have a number average molecular weight in the range of 800 to 10000, especially 1000 to 4000.

The epoxy resin (c) is then reacted with the compound of the formula (I)
It is reacted with the cyclic ester (d) of II). As the cyclic ester (d) used here, for example, δ-
Valerolactone, ε-caprolactone, ξ-enalactone, η-caprolactone, γ-valerolactone, δ-caprolactone, ε-enalactone, ξ-caprylolactone, and the like. A cyclic ester compound in which p is an integer of 4 to 6 and R ² is a hydrogen atom is preferred.

In the reaction between the epoxy resin (c) and the cyclic ester (d), the cyclic ester (d) opens the ring and reacts with the secondary hydroxyl group in the epoxy resin (c) to form a highly active primary hydroxyl group. , And the methylene chain portion originating from the lactone is presumed to impart flexibility and functionality to the epoxy resin (c).

The amount of the cyclic ester (d) to be reacted with the epoxy resin (c) is not strictly limited, but generally, the amount of the cyclic ester (d) in the modified epoxy resin (e) obtained by this reaction is not limited. The content (solid content) of the production unit derived from the cyclic ester is preferably 1 to 50% by weight, particularly preferably 5 to 20% by weight.

Epoxy resin (c) and cyclic ester (d)
The reaction with, usually without using a solvent, optionally in an inert atmosphere such as nitrogen, suitably in the presence of a catalyst such as dibutyltin oxide, dioctyltin oxide, tetrabutyl titanate, about 120 to about 200C And preferably at a temperature of about 150 to about 180 ° C. In the reaction, the reaction mixture is sampled with time and the amount of unreacted cyclic ester (d) is measured by measuring its infrared absorption spectrum, and the conversion of the cyclic ester (d) is 90% or more, preferably 95% or more. It can be terminated at the time when becomes.

According to the present invention, the lactone-modified epoxy resin (e) thus obtained is further reacted with an amine compound having active hydrogen.

Examples of the amine compound having active hydrogen include alkylamines such as methylamine, ethylamine, n-propylamine and isopropylamine, and alkanolamines such as ethanolamine, n-propanolamine and isopropanolamine. Primary monoamine compounds; dialkanolamines such as dialkylamines such as diethylamine, di-n-butylamine and di-n-propylamine, diethanolamines, di-n-propanolamine and diisopropanolamine;
Secondary monoamine compounds such as N-alkylalkanolamines such as methylethanolamine and N-ethylethanolamine; alkylenediamines such as ethylenediamine; polyalkylenepolyamines such as diethylenetriamine; hydroxyalkylamino such as hydroxyethylaminoethylamine Alkylamine, ethylaminoethylamine, methylaminopropylamine,
Primary and / or secondary polyamine compounds such as mono- or di-alkylaminoalkylamines such as dimethylaminoethylamine and dimethylaminopropylamine are included. Among them, diethanolamine and N-methylethanolamine are particularly preferable.

These amine compounds can be used as such with the lactone-modified epoxy resin (e), for example,
Ketones such as methyl ethyl ketone, methyl isobutyl ketone, butyl cellosolve, butanol, esters,
In an organic solvent such as an alcohol solvent, about 30 to about 150 ° C,
In particular, by reacting at a temperature of about 80 to about 120 ° C. for about 1 to 5 hours, the desired modified epoxy-polyamine resin (f) can be converted into a desired modified epoxy-polyamine resin (f). When a secondary amine having an alkyl group is used, generally, the amine is reacted with a ketone, aldehyde or carboxylic acid in advance by a conventional method, for example, by heating to a temperature of about 100 to about 230 ° C. After the conversion to aldimines, ketimines, oxazolines or imidazolines, the lactone-modified epoxy resin (e) is used, for example, preferably in an organic solvent as described above, at about 80 to about 200 ° C., especially about 80 to about 12 ° C.
By reacting at a temperature of 0 ° C. for about 1 to 5 hours,
It is desirable to produce the desired modified epoxy-polyamine resin (f).

In the above reaction, the amount of the amine compound to be used with respect to the lactone-modified epoxy resin (e) is not strictly limited, and the type of the lactone-modified epoxy resin and the desired product are desired for the modified epoxy-polyamine resin. In general, the amount is adjusted so that the amine value of the modified epoxy-polyamine resin (f) as the final product falls within the range of 15 to 100, particularly 20 to 70. Is desirable. If the modified epoxy-polyamine resin (f) has an amine value of less than 15, the water dispersibility of the resin decreases, and if it is larger than 100, the water resistance of a film formed using the resin deteriorates. , There is a tendency.

The modified epoxy prepared as described above
The polyamine resin (f) generally has 3 units of an alkylene oxide or alkylene glycol structural unit derived from the diepoxide compound (a) of the formula (I) or (II).
It can be contained within the range of -40% by weight, preferably 5-20% by weight.

The modified epoxy-polyamine resin (f) according to the present invention contains 5 to 30% by weight, preferably 5 to 20% by weight of a structural unit derived from the cyclic ester (d).
It can be contained within the range of% by weight.

Further, the modified epoxy-polyamine resin (f) is usually used in an amount of 1000 to 20,000, preferably 1 to 20,000.
It can have a number average molecular weight in the range of 500 to 10000 and, as mentioned above, 15 to 100, especially 2
It preferably has an amine value in the range of 0-70.

According to another aspect of the present invention, a bisphenol (b) is reacted with a diepoxide compound (a) and a bisphenol A type epoxy resin as described above, and the resulting epoxy resin (c) is reacted with a cyclic ester After reacting (d) to give a lactone-modified epoxy resin (e), before reacting with an amine compound having active hydrogen, the lactone-modified epoxy resin (e) is reacted with a partially blocked isocyanate compound (h); Then, the desired modified epoxy-polyamine resin (f) can be obtained by reacting with an amine compound having active hydrogen.

The partially blocked isocyanate compound (h) used in the above embodiment has a blocking ratio of 20 to
80%, preferably in the range of 40 to 70%. Such partially blocked polyisocyanate compounds include, for example, a polyisocyanate compound and an isocyanate blocking agent, and the number of isocyanate groups in the polyisocyanate compound / isocyanate The ratio of the number of active hydrogens in the blocking agent is 1 / 0.5 to 1 / 0.95, preferably 1
It can be obtained by reacting at a ratio such that it falls within the range of /0.6 to 1 / 0.9.

The term "blocking ratio" as used herein means that, when an isocyanate group in a polyisocyanate compound is reacted with active hydrogen of a blocking agent, the number of blocked isocyanates after the reaction relative to the total number of isocyanate groups before the reaction in the polyisocyanate compound. Means the ratio of the number of isocyanate groups applied.

The polyisocyanate compound is a compound having at least two isocyanate groups in one molecule, and specific examples thereof include aliphatic or alicyclic compounds such as hexamethylene diisocyanate, isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. Formula polyisocyanate compounds; aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, etc., among which isophorone diisocyanate and diphenylmethane-
4,4'-Diisocyanate is preferred. These can be used alone or in combination of two or more.

On the other hand, an isocyanate blocking agent is an active hydrogen-containing compound having a function of temporarily adding and blocking an isocyanate group of a polyisocyanate compound, and the partially blocked isocyanate compound (h) formed by the addition is It can be stable at normal temperature and can regenerate free isocyanate groups by dissociating the blocking agent when heated to about 140 ° C. to about 250 ° C.

Examples of the blocking agent satisfying such conditions include lactam compounds such as ε-caprolactam and γ-butyrolactam; methyl ethyl ketoxime;
Oxime compounds such as cyclohexanone oxime; phenol compounds such as phenol, para-t-butylphenol and cresol; aliphatic alcohols such as n-butanol and 2-ethylhexanol; aromatics such as phenylcarbinol and methylphenylcarbinol Alkyl alcohols; ether alcohol compounds such as ethylene glycol monobutyl ether;

The reaction ratio between the partially blocked isocyanate compound (h) and the modified epoxy resin (e) is generally 1/2 in terms of the solid content weight ratio of the compound (h) / resin (e).
It can be in the range of 0 to 1/1, preferably 1/10 to 1 / 2.5.

Partially blocked isocyanate compound (h)
The reaction of the modified epoxy resin (e) with the modified epoxy resin (e) can be carried out, for example, by reacting both components in an organic solvent such as a ketone-based solvent such as methyl ethyl ketone or methyl isobutyl ketone; or a hydrocarbon-based solvent such as xylene or toluene. ~ 120
The reaction can be carried out at a temperature of ° C. until substantially no free isocyanate groups are detected.

According to yet another aspect of the present invention, as described above, the diepoxide compound (a) and bisphenol A
Bisphenols (b) are reacted with the epoxy resin,
After reacting the obtained epoxy resin (c) with the cyclic ester (d), the obtained lactone-modified epoxy resin (e)
To a modified epoxy-polyamine resin (f) obtained by reacting an amine compound having an active hydrogen with a partially blocked isocyanate compound (h) as described above to obtain a urethane-modified epoxy-polyamine resin (g). It can also be.

Partially blocked isocyanate compound (h)
The reaction ratio between the modified epoxy-polyamine resin (f) and the solid content weight ratio of the compound (h) / resin (f) is generally 1/20 to 1/1, preferably 1/10 to 1/2. 5
Within the range.

Partially blocked isocyanate compound (h)
The reaction of the modified epoxy-polyamine resin (f) with the modified epoxy resin (f) can be carried out, for example, under the same conditions as described above for the reaction of the partially blocked isocyanate compound (h) with the modified epoxy resin (e).

The modified epoxy-polyamine resin (f) obtained as described above and the urethane-modified epoxy-
The polyamine resin (g) has a structure in which an alkylene oxide (or alkylene glycol) structural unit as a plastic component and a hard bisphenol structural unit are repeated at relatively short intervals in the molecule, so that the organic solvent or the organic solvent is low. Electrodeposition coating can be performed without lowering the electrodeposition properties even under an organic solvent, and since it has a highly active primary hydroxyl group derived from a cyclic ester in the side chain, it is not necessary to mix a lead compound. Has the advantage that a coating film having a sufficient anticorrosive property can be formed.
The polyamine resin (f) and the urethane-modified epoxy-polyamine resin (g) can be advantageously used as a base resin component in a coating resin composition, particularly a resin composition for a cationic electrodeposition coating.

When the modified epoxy-polyamine resin (f) or the urethane-modified epoxy-polyamine resin (g) is used in the coating resin composition, these resins can be used in combination with an external crosslinking agent. As the external cross-linking agent that can be used in combination, at least two cross-linkable functional groups (for example, a blocked isocyanate group) that can react with a reactive functional group (for example, a primary or secondary hydroxyl group) in the resin are used. Examples of such compounds include blocked polyisocyanate compounds, β-hydroxycarbamic acid esters of polyamines, malonic acid ester derivatives, methylolated melamine, and methylolated urea.

The mixing ratio (solid content ratio) of the modified epoxy-polyamine resin (f) or the urethane-modified epoxy-polyamine resin (g) and these external crosslinking agents is usually 1
It is preferably within the range of 00/0 to 60/40, particularly 90/10 to 60/40.

The resin composition comprising the modified epoxy-polyamine resin (f) or the urethane-modified epoxy-polyamine resin (g) according to the present invention is particularly useful as a resin for a cationic electrodeposition paint for preparing a cationic electrodeposition paint bath. Can be used to advantage. The preparation can be carried out by a method known per se. For example, such a resin can be used alone with an appropriate acid, for example, an inorganic acid such as boric acid, phosphoric acid, sulfuric acid or hydrochloric acid; or an organic acid such as lactic acid, acetic acid or formic acid alone. Alternatively, two or more kinds are used in combination to neutralize, and sufficiently stirred and mixed, and water is added to stably dissolve or disperse in water, and then, if necessary, such as carbon black, titanium white, and red iron. Coloring pigments; extender pigments such as clay and talc; rust preventive pigments such as strontium chromate;
Alternatively, it can be carried out by kneading other additives. Other additives that may be incorporated include, for example, a small amount of a nonionic surfactant as a dispersant or an anti-cissing agent for a coated surface; a curing accelerator (for example, a metal such as bismuth, tin, zinc, iron, or aluminum). Salts of and / or imidazoline compounds, imidazoles, phosphines,
Quaternary phosphonium salts).

Using the cationic electrodeposition coating bath prepared as described above, the electrodeposition coating is performed in the same manner as in the usual cationic electrodeposition coating, using the conductive coating object as a cathode, and after washing with water, About 10 minutes at a temperature of 150 to about 200 ° C
By baking for about 40 minutes, a cured coating having excellent coating performance can be obtained.

Thus, the coating resin composition provided by the present invention can be used in a wide range of fields, for example, in the field of undercoating of automobile bodies, industrial parts, and coating of home electric appliances.

[0059]

The present invention will be described more specifically with reference to the following examples. Hereinafter, simply “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

Production Example 1 A propylene oxide-modified bisphenol A diamine having an epoxy equivalent of about 340 and a total addition mole number of propylene oxide of about 2 to 3 was placed in a flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a reflux condenser. Glycidyl ether 340
Parts, 342 parts of bisphenol A, epoxy equivalent of about 19
570 parts of bisphenol A diglycidyl ether and 0.35 parts of dimethylbenzylamine.
The reaction was carried out at ℃ until the epoxy equivalent became 1,252. Next, 125 parts of ε-caprolactone and 0.025 parts of tetrabutoxytitanium were added, and the temperature was raised to 170 ° C.
Sampling was performed over time while maintaining this temperature, and the amount of unreacted ε-caprolactone was tracked by infrared absorption spectrum measurement. When the reaction rate became 98% or more, 241.2 parts of methyl isobutyl ketone and 84 parts of diethanolamine were used.
And 53.4 parts of a 80% pure diethylenetriamine in methyl isobutyl ketone solution of diketimine in methyl isobutyl ketone, reacted at 80 ° C. for 4 hours, diluted with 250 parts of methyl isobutyl ketone, resin solid content 75% and amine value A modified epoxy-polyamine resin of 44.4 was obtained.

Production Example 2 A flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a reflux condenser was charged with 300 parts of polypropylene oxide diglycidyl ether having an epoxy equivalent of about 300, 285 parts of bisphenol A, and about 190 parts of an epoxy equivalent. 570 parts of bisphenol A diglycidyl ether and 0.3 part of dimethylbenzylamine were charged and reacted at 160 ° C. until the epoxy equivalent became 955.3. Then, ε
-100 parts of caprolactone and 0.02 parts of tetrabutoxytitanium were added, the temperature was raised to 170 ° C, sampling was performed over time while maintaining this temperature, and the amount of unreacted ε-caprolactone was tracked by infrared absorption spectrum measurement. When the conversion reached 98% or more, 200 parts of methyl isobutyl ketone, 84 parts of diethanolamine and 53.4 parts of a methyl isobutyl ketone diketimine solution of diethylene triamine having a purity of 80% and 53.4 parts of methyl isobutyl ketone were added.
After reacting at 80 ° C. for 4 hours, methyl isobutyl ketone 200
To obtain a modified epoxy-polyamine resin having a resin solid content of 75% and an amine value of 54.2.

Production Example 3 A flask equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser was charged with 200 parts of tolylene diisocyanate, and 149.4 parts of 2-ethylhexanol was added thereto. ℃, while cooling
The solution was slowly dropped to synthesize a blocked isocyanate.

Production Example 4 In a flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a reflux condenser, a propylene oxide-modified bisphenol A diamine having an epoxy equivalent of about 340 and a total added mole number of propylene oxide of 2 to 3 was added. Glycidyl ether 340
Parts, bisphenol A 228 parts, epoxy equivalent of about 19
390 parts of bisphenol A diglycidyl ether and 0.3 parts of dimethylbenzylamine at 160 ° C.
The reaction was continued until the epoxy equivalent became 958. Then, 100 parts of ε-caprolactone and 0.02 part of tetrabutoxytitanium were added, the temperature was raised to 170 ° C., sampling was performed over time while maintaining this temperature, and the amount of unreacted ε-caprolactone was measured by infrared absorption spectrum measurement. Track,
When the conversion reached 98% or more, 241.1 parts of methyl isobutyl ketone were charged, and then 152 parts of the blocked isocyanate obtained in Production Example 3 was added.
After the reaction at 00 ° C. until the absorption of isocyanate groups disappeared by infrared absorption spectrum measurement, 84 parts of diethanolamine and 53.4 parts of a 80% pure solution of diethylenetriamine in methyl isobutyl ketone diketimine in methyl isobutyl ketone were added. After diluting with 194.2 parts of methyl isobutyl ketone, a urethane-modified epoxy resin having a resin solid content of 75% and an amine value of 50.0 was obtained.
A polyamine resin was obtained.

Production Example 5 285 parts of bisphenol A, 665 parts of bisphenol A diglycidyl ether having an epoxy equivalent of about 190 and 0.35 part of dimethylbenzylamine were placed in a flask equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser. And reacted at 160 ° C. until the epoxy equivalent reached 950. Next, 100 parts of ε-caprolactone and 0.02 part of tetrabutoxytitanium were added, the temperature was raised to 170 ° C, and sampling was performed over time while maintaining this temperature.
The amount of unreacted ε-caprolactone was traced by infrared absorption spectrometry. When the reaction rate reached 98% or more, 241.2 parts of methyl isobutyl ketone, 84 parts of diethanolamine, and methyl isobutyl ketone of diethylene triamine having a purity of 80% were obtained. After adding 53.4 parts of a diketimine solution in methyl isobutyl ketone and reacting at 80 ° C. for 4 hours, the mixture was diluted with 140.9 parts of methyl isobutyl ketone to obtain a resin solid content of 7%.
A 5% modified epoxy-polyamine resin having an amine value of 56.7 was obtained.

Production Example 6 In a flask equipped with a stirrer, thermometer, nitrogen inlet tube and reflux condenser, a propylene oxide-modified bisphenol A diamine having an epoxy equivalent of about 340 and a total added mole number of propylene oxide of 2 to 3 was added. Glycidyl ether 340
Parts, 342 parts of bisphenol A, epoxy equivalent about 190
Bisphenol A diglycidyl ether (570 parts) and dimethylbenzylamine (0.35 parts) were charged at 160 ° C.
The reaction was continued until the epoxy equivalent reached 1,252. Then, 241.2 parts of methyl isobutyl ketone, 84 parts of diethanolamine and 53.4 parts of a 80% pure diethylenetriamine methyl isobutyl ketone diketimine methyl isobutyl ketone solution were added, and the mixture was reacted at 80 ° C. for 4 hours. After dilution with 2 parts, a modified epoxy-polyamine resin having a resin solid content of 75% and an amine value of 48.5 was obtained.

Examples 1 to 3 and Comparative Examples 1 and 2 To each of the five types of base resin solutions obtained in the above Production Examples 1 to 6 were added methylethylketoxime-blocked isophorone diisocyanate, a blocked isocyanate group and a modified epoxy-polyamine resin. It was blended so as to be approximately equivalent to the total amount of primary hydroxyl groups and primary amino groups in the mixture.

The polypropylene glycol was added to 100 parts by weight of the solid content of the resin composition compounded as described above.
SANYO CHEMICAL INDUSTRIES, LTD. One part of SANNIX (Sannicks PP4000, manufactured by Sanyo Kasei Co., Ltd.) and 1.6 parts of acetic acid were added, and the mixture was heated to 60 ° C. and gradually added with deionized water while stirring to disperse the resin into solids. An emulsion with good stability of 30% was obtained.

This emulsion was charged into a flask capable of performing a reduced pressure operation, evaporated at 50 ° C. under reduced pressure until methyl isobutyl ketone was substantially eliminated, and then readjusted to a resin solid content of 30% with deionized water.

13 parts of titanium white, 0.3 part of carbon black, 3 parts of clay, 2 parts of dibutyltin oxide and 2 parts of a nonionic surfactant (trade name) are based on 100 parts by weight of the resin solid content of the aqueous emulsion thus obtained. : Neugen (NOIGEN)
142B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (DAI-ICHI KOGYO S
EIYAKU CO., LTD.)) And add 1 part.
After the pigment was dispersed to 0 μm or less, it was further diluted with deionized water to a solid content of 20%.

Using the five kinds of diluted paints obtained as described above, untreated steel sheet was subjected to cationic electrodeposition coating by applying a current of 3% at a solid concentration of 20%, a bath temperature of 28 ° C. and a voltage of 250 V for 3 minutes. . After baking these electrodeposited plates at 160 ° C. for 20 minutes, coating surface evaluation and anticorrosion test were performed. The resin formulation and test results are shown in Table 1 below.

The meaning of (note) in Table 1 is as follows. (Note 1) Thickness of the electrodeposited film when energized at 250 V for 3 minutes. (Note 2) Cross-cut wounds were made on the electrodeposited film with a knife to reach the substrate, and this was sprayed with salt water for 480 hours according to the description of JIS Z2371. A test was conducted to measure rust from knife scratches and blister width (mm).

[0072]

[Table 1]

Claims (29)

[Claims] 1. The following general formulas (I) and (II): In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, m and n are each 0 or more, and the sum of m and n is in the range of 1 to 20, and x is 1 Y is an integer of 1 to 50, and a diepoxide compound (a) selected from the group consisting of compounds represented by and a bisphenol A type epoxy resin having an epoxy equivalent of 170 to 500 are converted into a bisphenol ( b) to give the resulting epoxy resin (c) with the following general formula (III): In the formula, R ² represents a hydrogen atom or a methyl group, p is an integer of 3 to 6, a cyclic ester (d) represented by the following formula is reacted, and the obtained modified epoxy resin (e) is further reacted with active hydrogen. A coating resin composition comprising a modified epoxy-polyamine resin (f) obtained by reacting an amine compound having the following formula: 2. The composition according to claim 1, wherein the diepoxide compound (a) is a compound of formula (I) or (II) wherein R ¹ is methyl. 3. A compound of the formula (I) or a compound of formula (I), wherein the diepoxide compound (a) is such that the sum of m and n is in the range from 2 to 10.
Is a compound of formula (II) wherein is an integer in the range of 1-6 and y is a number in the range of 5-20. 4. A bisphenol A type epoxy resin comprising 20
The composition of claim 1 having an epoxy equivalent in the range of 0-400. 5. Bisphenol A type epoxy resin is 34
The composition of claim 1 having a number average molecular weight in the range of 0 to 1500. 6. A bisphenol A type epoxy resin represented by the following formula (VI): The composition according to claim 1, wherein q is a number in the range of 0 to 5. 7. The group in which the bisphenols (b) consist of bis (4-hydroxyphenyl) -2,2-propane, bis (4-hydroxyphenyl) -1,1-ethane and bis (4-hydroxyphenyl) methane The composition according to claim 1, which is selected from the group consisting of: 8. The method according to claim 1, wherein the bisphenol (b) is bis (4-hydroxyphenyl) -2,2-propane.
A composition according to claim 1. 9. The epoxy resin (c) is 400-5000.
The composition of claim 1 having an epoxy equivalent weight in the range: 10. The epoxy resin (c) is 800-100.
The composition of claim 1 having a number average molecular weight in the range of 00. 11. The cyclic ester (d) is selected from the group consisting of δ-valerolactone, ε-caprolactone, ξ-enalactone, η-caprolactone, γ-valerolactone, δ-caprolactone, ε-enalactone and ξ-caprylolactone. A composition according to claim 1, which is selected. 12. The composition according to claim 1, wherein the cyclic ester (d) is a compound of the formula (III) wherein R ² is a hydrogen atom and p is an integer of 4-6. 13. The composition according to claim 1, wherein the modified epoxy resin (e) contains 1 to 50% by weight of a structural unit derived from the cyclic ester (d). 14. An amine compound having active hydrogen is a first compound.
The composition according to claim 1, wherein the composition is selected from the group consisting of a primary monoamine compound, a secondary monoamine compound, and a primary and / or secondary polyamine compound. 15. The composition according to claim 1, wherein the amine compound having active hydrogen is diethanolamine or N-methylethanolamine. 16. Modified epoxy-polyamine resin (f)
Has an amine number in the range of 15-100. 17. Modified epoxy-polyamine resin (f)
Contains 3 to 40% by weight of an alkylene oxide or alkylene glycol structural unit derived from the diepoxide compound (a). 18. Modified epoxy-polyamine resin (f)
Contains 5 to 30% by weight of a structural unit derived from the cyclic ester (d). 19. Modified epoxy-polyamine resin (f)
Has a number average molecular weight in the range of 1,000 to 20,000. 20. A lactone-modified epoxy resin (e) by reacting a bisphenol (b) with a diepoxide compound (a) and a bisphenol A type epoxy resin, and reacting a cyclic ester (d) with the obtained epoxy resin (c). 2. The composition according to claim 1, wherein the lactone-modified epoxy resin (e) is reacted with a partially blocked isocyanate compound (h) before reacting with the amine compound having active hydrogen. 21. The composition according to claim 20, wherein the partially blocked isocyanate compound (h) has a blocking ratio in the range of 20 to 80%. 22. The composition according to claim 20, wherein the partially blocked isocyanate compound (h) is obtained by partially blocking isophorone diisocyanate or diphenylmethane-4,4′-diisocyanate. 23. The partially blocked isocyanate compound (h) is prepared by mixing the lactone-modified epoxy resin (e) with the compound (h) / resin (e) at a solid content weight ratio of 1/20 to 1/1.
21. The composition according to claim 20, wherein the reaction is carried out at a ratio falling within the range. 24. A coating comprising a urethane-modified epoxy-polyamine resin (g) obtained by further reacting a partially blocked isocyanate compound (h) with the modified epoxy-polyamine resin (f) according to claim 1. Resin composition. 25. The partially-blocked isocyanate compound (h) is prepared by modifying the modified epoxy-polyamine resin (f) and the solid content weight ratio of the compound (h) / resin (f) to 1/20 to 1/20.
The composition according to claim 24, wherein the reaction is carried out at a ratio falling within the range of 1. 26. The method according to claim 1, further comprising an external crosslinking agent.
Or the composition of 24. 27. A resin composition for a cationic electrodeposition coating comprising the composition according to claim 1 or 24. 28. A cationic electrodeposition paint bath comprising the composition according to claim 1 or 24. 29. An article coated with the composition according to claim 1 or 24.