JPS62220567A - Thermosetting coating resin composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by adding and blending a polyamine resin to a specific amine-modified polyepoxide, having low temperature curability, capable of giving films having improved external appearance, hardness, solvent and corrosion resistance and suitable for cation electrodeposition coating. CONSTITUTION:A composition obtained by adding and blending (B) 50-95pts.wt. polyamine resin having amino groups or imino groups with (A) 5-50pts.wt. amine-modified polyepoxide, obtained by linking (i) polyepoxide with (ii) an ethylenically unsaturated dibasic acid, e.g., glycol-bis-maleic acid, etc., conjugate with 2 carbonyl groups and adding (iii) a secondary amine having <=100 deg.C boiling point to the ethylenically unsaturated bonds of the resultant product and residual epoxy groups. The component (A) has preferably 0.5-2 isocyanate groups based on 1,000g resin added to hydroxyl groups in the resin side chain thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thermosetting coating resin composition suitable for cationic electrodeposition coating.

[Conventional technology]

In recent years, cationic electrodeposition coating has come to be widely used as an undercoat coating mainly for the purpose of rust prevention, mainly in the automobile industry.

The resin used in such cationic electrodeposition coating is mainly polyepoxide such as polyglycidyl ether of bisphenol A, which has excellent corrosion resistance. JP-A No. 55-31889 discloses a resin composition using the above-mentioned polyepoxide, in which an α,β-ethylenically unsaturated compound conjugated with a carbonyl group is introduced into the polyepoxide.
An amino-modified polyepoxide in which a primary amine or a secondary amine is added to α, β-ethylenically unsaturated bonds in the resin, and is made into a Michael adduct that becomes unstable during heat curing;
It has been disclosed that after mixing with a polyamine resin having an amino group or an imino group, the mixture is neutralized with an acid and diluted with water to form an aqueous dispersion suitable for cationic electrodeposition coating.

In this resin composition, an α,β-ethylenically unsaturated compound conjugated with a carbonyl group, which is essential for thermosetting, is introduced into polyepoxide to obtain a cationic electrodeposited coating film with excellent low-temperature curability. α,β-ethylenically unsaturated acids such as acrylic acid and methacrylic acid and N-alkoxymethylacrylamides such as N-butoxymethylacrylamide are disclosed.

[Problem that the invention seeks to solve]

However, α,β-ethylenically unsaturated acids have been used as polyesters of bisphenol A, which is widely used in the cationic electrodeposition coating field.
When introducing into a polyepoxide such as liglycidyl ether, the above unsaturated acid is added to the epoxy group at the end of the polyepoxide and introduced into the polyepoxide in the form of an ester bond as an acryloyl (or methacryloyl) group. The higher the molecular weight of the resin, the lower the number of α, β-ethylenically unsaturated bonds in the resin.
As a result, it becomes difficult to obtain a coating film with good low-temperature curability, and the ester bonds at the ends of the resin are easily hydrolyzed in the aqueous dispersion.
, the number of β-ethylenically unsaturated bonds is further reduced, and α is produced by hydrolysis.

As a result of the incorporation of β-ethylenically unsaturated acids into the paint bath, the thermosetting properties of the paint film obtained with aged paints are significantly reduced.
Not only will the appearance and performance of the paint film become poor, but it will also make bath management difficult.

In the case of N-alkodimethylacrylamide, it is introduced into the polyepoxide through a transetherification reaction between the hydroxyl group in the polyepoxide and the N-alkoxymethylacrylamide. According to this method, α, which is conjugated with the carbonyl group, β-ethylenically unsaturated bonds can be introduced into the resin as amide bonds with excellent hydrolysis resistance, and the number of such bonds can be increased compared to α,β-ethylenically unsaturated acids. , Michael addition of an amino group or imino group to an α,β-ethylenically unsaturated bond conjugated with a carbonyl group forming an amide bond is a Michael addition of an amino group or an imino group to an α,β-ethylenically unsaturated bond conjugated with a carbonyl group forming an ester bond. It is difficult to obtain excellent low-temperature curability, and it is also difficult to react all of the N-alkoxymethyl acrylamide with the hydroxyl groups in the polyepoxide, so it is difficult to react with unreacted N-alkoxymethyl acrylamide. In addition to remaining in the produced resin, p-
Since a strong acid such as toluenesulfonic acid is used as a transetherification catalyst, unreacted N-alkoxymethylacrylamide and the strong acid of the catalyst may be mixed into the electrodeposited coating film or mixed into the bath, causing the coating to deteriorate. This may also result in poor film appearance and deterioration in coating film performance.

[Means for solving problems]

As a result of extensive research in order to solve the above problems, the present inventors have developed the Michael addition reaction of a primary amine or a secondary amine to an ethylenically unsaturated bond conjugated with a carbonyl group, as disclosed in Japanese Patent Application Laid-Open No. 55 Ethylenically unsaturated bonds that are conjugated with two carbonyl groups are better than α,β-ethylenically unsaturated bonds that are conjugated with only one carbonyl group to form an ester as disclosed in No. 31889. , found that the reactivity was extremely high.

Furthermore, by linking the polyepoxide with an ethylenically unsaturated dibasic acid that is conjugated with two such carbonyl groups, even if the molecular weight becomes high, the ethylenically unsaturated dibasic acid that is conjugated with two carbonyl groups in the resin can be bonded. It is possible to contain a high ratio of the number of saturated bonds, and there is no risk that the ethylenically unsaturated dibasic acid conjugated with the two carbonyl groups during the connection will remain as an unreacted product. Ester bonds in amino-modified polyepoxides obtained by Michael addition of secondary amines to polyepoxides linked by ethylenically unsaturated dibasic acids conjugated with carbonyl groups are formed by the polyepoxide surrounding the ester bonds and the Michael-added secondary amines. In addition to finding that it is difficult to hydrolyze due to the stereochemical effect of
An amino-modified polyepoxide that is made into a Michael adduct by adding a secondary amine with a boiling point of 100°C or less to an ethylenically unsaturated bond conjugated with a carbonyl group, which becomes unstable during heat curing, and a polyamine having an amino group or an imino group. A baked coating film obtained by cationic electrodeposition coating with an aqueous dispersion obtained by neutralizing a thermosetting resin composition obtained by mixing it with an acid and diluting it with water is disclosed in JP-A-55- 31889
It has low-temperature curing properties that are 20 to 30 degrees Celsius lower than the baking temperature disclosed in the above issue, and also exhibits excellent appearance, corrosion resistance, hardness, and solvent resistance. The present invention has been completed based on the discovery that the bath stability of the method can be maintained stably over a long period of time.

That is, in the present invention, after connecting polyepoxide with an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups, a secondary amine having a boiling point of 100°C or less is added to the ethylenically unsaturated bond and the remaining epoxy group. and 5 to 50 parts by weight of an amino-modified polyepoxide having a number average molecular weight of 1500 to too much.

Polyamine resin having amino group or imino group 50~
This is a thermosetting coating resin composition consisting of 95 parts by weight.

The amino-modified polyepoxide used in the present invention is produced by linking the polyepoxide with an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups, and more preferably after adding isocyanate to some or all of the hydroxyl groups in the resin. , is synthesized by adding a secondary amine having a boiling point of 100°C or less to the remaining epoxy group and ethylenically unsaturated bond.

The polyepoxide used in the synthesis of amino-modified polyepoxide is a compound having one or more 1,2-epoxy groups, and such polyepoxides include polyglycidyl ethers of polyphenols, ethylene oxide adducts or propylene oxide adducts of polyphenols. Polyglycidyl ethers of oxyalkylated adducts such as.

Examples include polyglycidyl ether of novolak phenolic resin.

Examples of polyphenols include bisphenol A (2,2-bis(4-hydroxyphenyl)propane), 1,1-bis(4-hydroxyphenyl)ethane, 2-methyl-1,1-bis(4-hydroxyphenyl)ethane, and 2-methyl-1,1-bis(4-hydroxyphenyl)ethane. -hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-
Examples include t-butylphenyl)propane, bis(2-hydroxynaphthyl.)methane, and 1,5-dihydroxynaphthalene.

Other polyepoxides include epoxidized polyalkadiene resins, glycidyl acrylate-1 to copolymer resins, glycidyl methacrylate copolymer resins, polyglycidyl ethers of hydroxyl group-containing resins, and polyglycidyl esters of carboxyl group-containing resins. can be given.

Polyepoxide is further reacted to cause chain extension,
Chain extenders which may increase the molecular weight include, for example, dimer acids.

Examples include active hydrogen-containing compounds that are reactive with epoxy groups, such as polyether polyols, polyester polyols, hydantoin, bisphene, Nord A, polyamides, and amino acids.

Next, examples of ethylenically unsaturated dibasic acids conjugated with two carbonyl groups used as a linking agent for polyepoxide include maleic acid and fumaric acid, as well as glycol synthesized by the reaction of maleic anhydride and glycol. −
Bis-maleic acid, especially glycol-bis-
Maleic acid is preferred.

Examples of glycol-bis-maleic acid include ethylene glycol-bis-maleic acid, propylene glycol-bis-maleic acid, 1,3-butylene glycol-bis-maleic acid, 1,6-hexanethiol-bis-maleic acid, 2.5-hexanediol-bis-maleic acid, neopentyl glycol-bis-maleic acid,
A glycol synthesized by the reaction of hydrogenated bisphenol A-bis-maleic acid, bisphenol dihydroxypropyl ether-bis-maleic acid, and glycol obtained by polycondensation of the glycols in the above-mentioned glycol-bis-maleic acid with maleic anhydride. -bis-maleic acid, etc. Examples of such glycol-bis-maleic acid include polyethylene glycol-bis-maleic acid represented by the formula and polypropylene glycol-bis-maleic acid represented by the formula %.

Particularly preferred is glycol-bis-maleic acid.

Glycol-bis-maleic acid is composed of glycol having a molecular structure that increases the hydrolysis resistance of the ester bond in glycol-bis-maleic acid. 5
-Hexanediol-bis-maleic acid, hydrogenated bisphenol A-bis-maleic acid, bisphenol dihydroxypropyl ether-bis-maleic acid, and other glycol-bis-maleic acids made of glycols having a secondary hydroxyl group.

Next, the isocyanate added to the hydroxyl group in the polyepoxide linked by the ethylenically unsaturated dibasic acid conjugated with the above two carbonyl groups includes monoisocyanate, diisocyanate, and partially blocked isocyanate derived from these. Examples include polyisocyanate.

First, monoisocyanates include, for example, methyl isocyanate, ethyl isocyanate, n-propylisocyanate, isopropylisocyanate, ethylene isocyanate, n-butyl isocyanate, isobutyl isocyanate, t-butyl isocyanate, and cyclopentyl isocyanate.

Diethylacetyl isocyanate, phenyl isocyanate, p-methoxyphenylisocyanate.

Examples include benzoyl isocyanate, p-ethoxyphenylisocyanate, p-carbomethoxyphenylisocyanate, p-dimethylaminophenyl isocyanate, undecyl isocyanate, 4-biphenylylisocyanate, diphenylmethylisocyanate.

Next, as the diisocyanate, for example, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 4,
4-diphenylmethane diisocyanate, 2.4-tolylene diisocyanate.

2.6-1~lylene diisocyanate, 1,4-xylylene diisocyanate, 4.4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4-
Examples include diphenyl ether diisocyanate.

Blocking agents that partially block the above diisocyanates include, for example, n-butanol, diisocyanate, etc.
- Aliphatic alcohols such as ethylhexanol, aromatic alkyl alcohols such as phenyl carbinol and methylphenyl carbinol, ether bond-containing alcohols such as ethyl cellosolve and butyl cellosolve, and phenol.

Phenols such as cresol, oximes such as acetone oxime and methyl ethyl ketoxime.

Examples include lactams such as E-caprolactam and γ-caprolactam.

The main purpose of adding isocyanate to the hydroxyl group in the polyepoxide linked by an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups is to form a urethane bond in the side chain in the resin, and the subsequent secondary The basicity of the amine is adjusted by the steric effect of isocyanate on the amine of the Michael addition bond in the amino-modified polyepoxide obtained by addition of the amine, and the water dispersion stability of the amino-modified polyepoxide in the cationic electrodeposition paint is improved. It's about preserving.

Further, the number of isocyanates used here may be appropriately determined depending on the number of ethylenically unsaturated bonds in the polyepoxide linked by ethylenically unsaturated dibasic acids conjugated with two carbonyl groups, Usually, the number is 0.5 to 2 per 1000 g of amino-modified polyepoxide resin.

The type of incyanate to be used may be determined from among monoisocyanates, diisocyanates, and partially blocked polyisocyanates derived from these, particularly when partially blocked polyisocyanates are used.

The amount used and the type of blocking agent may be determined in consideration of the curability and performance of the coating film obtained by subsequent cationic electrodeposition coating.

Next, the tertiary amine to be added to the ethylenically unsaturated bonds and remaining epoxy groups in the polyepoxide obtained as described above has one imino group in one molecule and has a boiling point of 100°C or less. Such tertiary amines include dimethylamine, diethylamine, methylethylamine, methyl-n-propylamine, methylisopropylamine, methyl-n-butylamine, methylisobutylamine, ethyl-n-propylamine, Examples include secondary monoamines having 1 to 5 carbon atoms such as ethylisopropylamine and allylmethylamine.

Here, the reason why a secondary monoamine is used as the secondary amine to be added to the ethylenically unsaturated bond and the remaining epoxy group in the polyepoxide and m-mo/amine is not used is that the primary monoamine has active hydrogen in its molecule. This is because there is a risk of gelation during the addition reaction to ethylenically unsaturated bonds and remaining epoxy groups.

The reason for using a secondary monoamine with a boiling point of 100°C or less is that when a 27th monoamine with a boiling point of over 100°C is used, the Michael addition bond in the resulting paint film resin is Because of its good stability at low temperatures, active ethylenically unsaturated bonds are difficult to regenerate due to detachment and volatilization of secondary monoamines, and sufficient low-temperature curability can be obtained by adding 7-mino or imino groups in the polyamine resin. This is because it disappears and is not desirable.

Next, a method for synthesizing the amino-modified polyepoxide used in the present invention will be described.

First, a method for linking a polyethylene box and a polycarbonate with an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups will be explained.

Adding an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups, a suitable catalyst and an organic solvent to a reaction vessel,
Heat under a stream of inert gas and stir gently until heated to 50~
The temperature is raised to 80'C to form a uniform liquid.

Next, polyepoxide was added at 50 to 80°C, heated with sufficient stirring to make a uniform liquid, and then heated to 100°C.
Thereafter, the reaction is continued preferably at 80-100'C for 2-6 hours until the resin acid value becomes 1 or less.

Suitable organic solvents used at this stage include:

For example, toluene, xylene, methyl isobutyl ketone, diisopropyl ketone, mineral spirit, ethylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, butyl acetate and the like are preferred.

Suitable catalysts used at this stage include tertiary amines and quaternary ammonium salts such as dimethylethanolamine and tetramethylammonium chloride.

Next, a method of addition reaction between a hydroxyl group in a polyepoxide linked by an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups and an isocyanate will be described.

This addition reaction is carried out subsequent to the above reaction, and the isocyanate is gradually added over 10 to 30 minutes to the above polyepoxide which has been thoroughly stirred at a temperature of 50 to 90°C, followed by further reaction for 1 to 3 hours. Continue.

The organic solvent used in this ninth step may be the organic solvent used to obtain the above polyepoxide.

Next, the polyepoxide is linked with an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups.

Furthermore, a method will be described in which, after adding isocyanate to some or all of the hydroxyl groups in the resin, a low-boiling tertiary amine is added to the remaining epoxy groups and ethylenically unsaturated bonds.

This reaction is carried out subsequent to the above reaction, and a secondary amine is added to the homogeneous liquid material made of the polyepoxide described above while stirring it under an inert gas stream at an appropriate temperature.

The amount to be added is sufficient as long as it is the amount necessary to complete the reaction, but it is important to use an amine with a low boiling point of 100°C or less, and to mix it with the polyamine resin having an amino group or imino group afterwards. The amount of secondary amine used is preferably 1.2 to 2 times the required amount because it is necessary to complete the addition of the secondary monoamine to the ethylenically unsaturated bond in order to prevent gelation due to .

Further, the addition method is carried out by methods such as whole amount preparation, one-part preparation, and dropwise preparation.

The reaction conditions at this stage may be 70 to 100°C for 1 to 4 hours, but using a secondary amine with a low boiling point,
And because the addition of the second monoamine to the ethylenically unsaturated bond conjugated with two carbonyl groups occurs extremely quickly even at low temperatures compared to the addition to the epoxy group of polyepoxide.

First, the reaction is carried out at 30 to 80°C, preferably 40 to 70°C for 1 to 2 hours, and then the reaction is completed at 70 to 100°C for 1 to 4 hours, and the pressure inside the reaction vessel is reduced to -30 to -60°C.
The pressure was reduced to 11 g cm, and vacuum distillation was carried out at 60 to 100°C for 0.5 to 1 hour to remove unreacted amines and organic solvents, and the inside of the reaction vessel was returned to atmospheric pressure. A solvent such as ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, butyl alcohol, isopropyl alcohol, diacetone alcohol, etc. is added to obtain an amino-modified polyepoxide in a resin solution.

The number average molecular weight of the amino-modified polyepoxide obtained here must be 1,500 to 10,000, and the number average molecular weight is 1.
If it is less than 500, a cured coating film with sufficient performance in terms of corrosion resistance, physical properties, chemical resistance, etc. cannot be obtained;
If it exceeds 000, a cured coating film with a good coating appearance cannot be obtained.

In addition, the number of ethylenically unsaturated bonds conjugated with the two carbonyl groups contained in the amino-modified polyepoxide is an important factor that affects low-temperature curability and other coating properties, and in order to achieve this purpose, , preferably 0.5 or more, and particularly preferably 0.5 to 2 per 1000 g of amino-modified polyepoxide resin.

Polyamine resins having amino groups or imino groups (hereinafter simply referred to as polyamine resins) used as other components in the present invention include, for example, reaction products of polyepoxides and primary amines, polyepoxides and ketimine-blocked amino group-containing polyamines. Examples include reaction products with

The polyepoxide used in the synthesis of the polyamine resin may be the same as that used in the synthesis of the 7-mino-modified polyepoxide of the present invention.

Next, examples of amines used to add to polyepoxide to obtain a polyamine resin having amino groups or imino groups include primary amines and ketimine-blocked amino group-containing polyamines.

First, the primary amine reacts with the epoxy group of polyepoxide to form an imino group useful for the subsequent curing reaction. Examples of such primary amine include propylamine, butylamine, amylamine, -Ethylhexylamine.

Primary monoamines such as monoethanolamine are preferred.

In addition, after the ketimine-blocked amino group-containing polyamine reacts with the epoxy group of polyepoxide, the ketimine group is hydrolyzed by the addition of water, forming an amino group useful for the subsequent curing reaction. As the ketimine-blocked amino group-containing polyamine,
For example, amino groups in polyamines such as diethylenetriamine, monomethylaminopropylamine, dipropylenetriamine, diethylenetriamine, triethylenetetramine, etc.
Examples include those converted to ketimine by a ketone-stopping reaction such as methyl isobutyl ketone.

Next, a method for synthesizing the polyamine resin used in the present invention will be described.

A reaction vessel is charged with polyepoxide and a suitable organic solvent, and the mixture is stirred with gradual heating under a stream of inert gas to form a homogeneous liquid.

Then, the above uniform liquid material is heated at 60 to 120°C, preferably L<
The temperature is maintained at 80-100°C and the amine is added.

The amine is added by a method such as whole amount charging, divided charging, or dropwise charging, and the type and amount of the amine can be changed depending on the timing of the process. The reaction conditions at this stage are such that the reaction is carried out at the above temperature for 0.5 to 2 hours.

Also, if the amine used is a primary monoamine,
What amount should be used to prevent gelation?

The amount is preferably 1.2 to 2 times the equivalent number of epoxy groups to be reacted.

The organic solvent used at this step is preferably an inert solvent such as toluene, xylene, methyl isobutyl ketone, diisopropyl ketone, or the like.

Next, amine was added to the polyepoxide, and after the reaction was completed, 1
Reduce the pressure inside the reaction vessel to -30 to -60ca+Hg, perform vacuum distillation at 80 to 120°C for 0.5 to 1 hour to remove unreacted amines and organic solvents, and bring the inside of the reaction vessel to atmospheric pressure. A solvent suitable for subsequent water dispersion (same as in the case of the amino-modified polyepoxide) is added to obtain a polyamine resin in the form of a resin solution.

To synthesize polyamine resin, add amine to polyepoxide, remove unreacted amine by vacuum distillation,
If necessary, other components such as partially blocked polyisocyanate may be reacted and used. Such partially blocked polyisocyanates may be those used to synthesize the amino-modified polyepoxide used in the present invention, and the amount used and the type of blocking agent may vary depending on the type of blocking agent obtained according to the present invention. It may be determined as appropriate depending on the curability and coating performance of the paint film to be applied.

The proportions of the amino-modified polyepoxide and polyamine resin constituting the thermosetting coating resin composition of the present invention are 5 to 50 parts by weight and 50 to 95 parts by weight, respectively, which have excellent low-temperature curability and coating film. This is the ratio necessary to obtain quality; if the ratio is other than this, it will be difficult to obtain sufficient low-temperature curability and coating film quality.

The thermosetting coating resin composition of the present invention consists of an amino-modified polyepoxide and a polyamine resin in the above ratio,
The amines in the mixture can be added to, for example, formic acid, acetic acid, lactic acid,
By neutralizing with organic or inorganic acids such as phosphoric acid,
To obtain an aqueous dispersion that can be converted into a cationic base and is suitable for cationic electrodeposition coating by further diluting with water.

I can do it.

The above aqueous dispersion may contain other ingredients such as plasticizers, surfactants, pigments (e.g. titanium dioxide, carbon black, talc, kaolin, silica, lead silicate, basic lead chromate, zinc phosphate, etc.). (coloring pigments (containing facial acids, anti-rust pigments, etc.), organic solvents (e.g. hydrophilic or semi-hydrolytic solvents such as butyl alcohol, isopropyl alcohol, diacetone alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether) , add water, etc. as appropriate, and use a disilver or homo mixer, which is usually used to produce * ingredients.

Uniformly mixed and dispersed using mixers and dispersing machines such as sand grind mills, attritors, and roll mills,
It is possible to obtain a cationic electrodeposition paint which is an aqueous dispersion having a resin solid content of approximately 10 to 30% by weight.

〔Effect of the invention〕

The thermosetting coating resin composition of the present invention has a baking temperature of 150 to 160°C, which is 20 to 30°C lower than that of conventional resin compositions.
It has low-temperature curability that can be cured sufficiently even at ℃, and has a good appearance and
It is possible to obtain a cationic electrodeposited coating film having excellent quality in hardness, solvent resistance, and corrosion resistance, and to maintain such coating film quality and electrocoated paint bath stability for a long period of time.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, in which 1 part means part by weight, and % means % by weight.

Example 1 436 parts of hydrogenated bisphenol A-bis-maleic acid and 10.7 parts of dimethylethanolamine were placed in a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet under a nitrogen gas flow. and 495 parts of methyl isobutyl ketone were charged, and the temperature was gradually raised to 70°C to dissolve them. Then, polyepoxide (Yuka Shell Epoxy Co., Ltd. g!, Epicor 1~#828, trademark,
Add 744 parts (same below) and gradually raise the temperature to 90-100.
After the reaction temperature was maintained at 90 to 100°C and the reaction was continued for about 4 hours until the acid value became 1 or less, 487 parts of methyl isobutyl ketone was added and immediately cooled, and the temperature was lowered to 80°C. Then, 293 parts of p-ethoxyphenylisocyanate was added at 80°C, and the reaction was continued for 1 hour while being maintained at 80°C, then the temperature was raised to 90°C, and the reaction was continued for an additional 0.5 hour while maintaining the temperature at 90°C. It was then immediately cooled down to a temperature of 60°C. Then diethylamine 345 at 60°C
After adding 80% of
The temperature was raised to 80°C, and the reaction was carried out for 3 hours while maintaining the temperature at 80°C. Then, after stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -30 to -30C++HH, and the temperature was increased to 70 to 90C.
After distilling under reduced pressure for 40 minutes to remove unreacted amine and methyl isobutyl ketone, the inside of the reaction vessel was returned to atmospheric pressure, and 352 parts of ethylene glycol monoethyl ether was added at 80°C. An amino-modified polyepoxide resin solution A having a solid content of 80.0% and a number average molecular weight of 1,760 was obtained.

Here, the number of Michael-added ethylenically unsaturated bonds and isocyanate in the amino-modified polyepoxide resin solution A is per 1000 g of the resin.

The numbers were 1.1 and 1.0, respectively.

Also, in another reaction vessel similar to that used to synthesize the above amino-modified polyepoxide resin solution A.

950 parts of polyepoxide (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat #1004) and 48 parts of xylene were charged.

The temperature was gradually raised to 140-150°C to remove water present in the resin.

The temperature was then lowered to 80°C, and 520 parts of methyl isobutyl ketone and diketimine (diethylenetriamine 1
2 moles of methyl isobutyl ketone) were added.

Then, after reacting at 80 to 100°C for about 1 hour, 120°C
After raising the temperature to ℃ and stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -40 to -60 cmHg, and after distilling under reduced pressure for about 1 hour to remove methyl isobutyl ketone, the inside of the reaction vessel was greatly reduced. After returning to atmospheric pressure and lowering the temperature to 100°C, 241 parts of ethylene glycol monobutyl ether was added.
By thoroughly stirring, a yellowish-brown transparent polyamine resin solution-1 having a solid content of 79.0% and a number average molecular weight of 1900 was obtained.

Next, after thoroughly mixing amino-modified polyepoxide resin solution A and polyamine resin solution-1 at a fixed ratio, acetic acid was added and stirred thoroughly, and water was gradually added to reduce the solid content to 10.
An aqueous dispersion suitable for cationic electrodeposition coating of
A baked paint film was obtained and various performances were evaluated. The composition of the aqueous dispersion is shown in Table 1, and the cationic electrodeposition coating voltage, temperature characteristics, and various performance properties of the aqueous dispersion are shown in Table 2.

Example 2 Into the same reaction vessel as in Example 1, 654 parts of hydrogenated bisphenol A-bis-maleic acid, 10.7 parts of dimethylethanolamine, and 709 parts of methyl isobutyl ketone were charged under a nitrogen gas stream, and the mixture was gradually heated to 70°C. It was dissolved by increasing the temperature.

Then, polyepoxide (oiled shell epoxy) was heated at 70°C.
(manufactured by Tobu Kasei Co., Ltd., Epicoat #828) 372 parts and polypropylene glycol diglycidyl ether (Tobu Kasei Co., Ltd.)
Co., Ltd., PG-' 207, trademark, hereinafter the same) was added, and the temperature was gradually raised to 90 to 100°C, and then 90
After the reaction was continued for about 4 hours while maintaining the temperature at ~100°C until the acid value became 1 or less, 782 parts of methyl isobutyl ketone was added and immediately cooled, and the temperature was lowered to 80'C.

Then, a 2,4-tolylene diisocyanate resin solution 92 was semi-blocked with 2-ethylhexanol at 80°C.
After adding 9 parts (solid content 85.0%, resin solution dissolved in methyl isobutyl ketone) and continuing the reaction at 80°C for 1 hour, the temperature was raised to 90°C. The reaction was allowed to proceed for .5 hours. It was then immediately cooled down to a temperature of 60°C.

Next, nitrogen gas was passed through the dimethylamine aqueous solution at 60°C, and the vaporized dimethylamine was gradually introduced into the container to cause a reaction. The amount of dimethylamine used in the reaction was 230 parts. Dimethylamine was placed in a container according to the above method for 3 hours at 60°C and reacted, and then the temperature was raised to 80°C.
The reaction was carried out for 3 hours while maintaining the temperature at 80°C.

Then, after stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -30''-60cm11g, and the temperature was 40°C at 70 to 90°C.
After distilling under reduced pressure for 0 minutes to remove unreacted amine and methyl isobutyl ketone, the inside of the reaction vessel was returned to atmospheric pressure.
Ethylene glycol monobutyl ether 525 at 80°C
Add 50% of the solids and stir well to obtain a brownish-transparent solid content of 78%.
．． An amino-modified polyepoxide resin solution B having a concentration of 5% and a number average molecular weight of 5,200 was obtained.

Here, the number of Michael-added ethylenically unsaturated bonds and isocyanate in amino-modified polyepoxide resin solution B is per 1000 g of the resin.

The numbers were 1.1 and 1.0, respectively.

In addition, in another reaction vessel similar to Example 1, polyepoxide (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat #1001) was added.
) 507 parts, xylene 24 parts, 140-15
The temperature was gradually raised to 0°C to remove water present in the resin.

Then, the temperature was lowered to 120°C, 145 parts of dimer acid (manufactured by Daiichi General Co., Ltd., Persatime #216.trademark) and 1 part of dimethylethanolamine were added, and the temperature was lowered to 120°C.
The mixture was kept at ℃ and stirred for about 2 hours. After the acid value became 1 or less, it was cooled to 80°C, and 63 parts of diketimine (mentioned above, Example 1) and 25 parts of monoketimine (produced from 1 mol of monomethylaminopropylamine and 1 mol of methyl isobutyl ketone) were added. Added a section.

Then, after reacting at 80 to 100°C for about 1 hour, 120°C
After raising the temperature to ℃ and stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -40 to -60c+aHg, distilled under reduced pressure for about 1 hour to remove xylene under reduced pressure, and then the inside of the reaction vessel was reduced to atmospheric pressure. After lowering the temperature to 100°C, 148 parts of ethylene glycol monobutyl ether was added and thoroughly stirred to obtain a yellow-brown transparent polyamine resin solution-2 with a solid content of 80.0% and a number average molecular weight of 2900. Ta.

Next, an aqueous dispersion suitable for cationic electrodeposition coating was prepared from amino-modified polyepoxide resin solution B and polyamine resin solution-2 in the same manner as in Example 1, and its various coating film performances were evaluated. The composition of the aqueous dispersion is shown in Table 1, and its cationic electrodeposition coating voltage, temperature characteristics, and various coating film performances are shown in Table 2.

Example 3 In a reaction vessel similar to Example 1, 2.5-
471 parts of hexanediol-bis-maleic acid.

9.6 parts of dimethylethanolamine and 693 parts of methyl isobutyl ketone were charged, and the temperature was gradually raised to 70°C to dissolve them.

Then, at 70°C, 588 parts of polyepoxide (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat #1001), 377 parts of polypropylene glycol diglycidyl ether (ml, PG-207, manufactured by Tobu Kasei Co., Ltd.), and neopentyl glycol diglycidyl ether, (manufactured by Tobu Kasei Co., Ltd.).

Add 180 parts of PG-202) and gradually raise the temperature to 90
After raising the temperature to 100°C, maintain the temperature at 90~100°C until the acid value reaches 1.
After continuing the reaction for about 4 hours until the temperature reached
The temperature was lowered to 0°C. Next, 334 parts of a 2,4-tolylene diisocyanate resin solution semi-blocked with 2-ethylhexanol (solid content 85.0%, resin solution dissolved in methyl isobutyl ketone) and 45 parts of p-methoxyphenylisocyanate were added at 80°C. The reaction was continued for 1 hour while maintaining the temperature at 80°C, and then the temperature was raised to 90°C.

The reaction was continued for an additional 0.5 hour while maintaining the temperature at 90°C.

It was then immediately cooled down to a temperature of 60°C.

Next, in the same manner as in Example 2 at 60°C, 209 parts of dimethylamine was gradually introduced into the container and reacted for 3 hours, then the temperature was raised to 80°C, and the temperature was maintained at 80°C for an additional 3 hours. Allowed time to react.

Then, after stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to 1 g (-3Q~-60c+m), and the temperature was increased to 70~90℃.
After distilling under reduced pressure for 40 minutes to remove unreacted amine and methyl isobutyl ketone, the inside of the reaction vessel was returned to atmospheric pressure, and 430 parts of ethylene glycol monoethyl ether was added at 80°C. An amino-modified polyepoxide resin solution C having a solid content of 78.0% and a number average molecular weight of 7,100 was obtained.

Here, the numbers of Michael-added ethylenically unsaturated bonds and isocyanates in the amino-modified polyepoxide resin solution C are each 1.4 per 1000 g of the resin.
and 0.6 pieces.

Next, amino-modified polyepoxide resin solution C and Example 1
The polyamine resin solution-1 used in Example 1 was used in the same manner as in Example 1, and was suitable for cationic electrodeposition coating.

Aqueous dispersions were prepared and their various coating properties were evaluated.

The composition of the aqueous dispersion is shown in Table 1, and its cationic electrodeposition coating voltage, bath properties and various coating performances are shown in Table 2.

Comparative Example 1 In a reaction vessel similar to Example 1, 1200 parts of polyepoxide (manufactured by Yuka Shell Co., Ltd., Epicoat #1004) was added.

550 parts of ethyl cellosolve, 94 parts of acrylic acid, 30% ethylene glycol monoethyl ether of hydroquinone
13 parts of solution and 7 parts of 30% methanol solution of tetramethylammonium chloride were charged, and under nitrogen gas, 1
Heated at 30°C for 5 hours, then cooled and lowered the temperature to 60°C.

Then, 124 parts of diethylamine was added at 60°C, and the reaction was continued for 1 hour while maintaining the temperature at 60°C, then the temperature was raised to 80°C, and the reaction was continued for 3 hours while maintaining the temperature at 80°C.

Then, after stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -30 to -60c@Hg, and the temperature was increased to 40℃ at 70 to 90℃.
After distilling under reduced pressure for one minute to remove the volatile components methanol and unreacted amine, the inside of the reaction vessel was returned to atmospheric pressure and thoroughly stirred to produce a brownish-transparent solid content of 73.0%.
An amino-modified polyepoxide resin solution having a number average molecular weight of 1900 was obtained.

Here, the number of Michael-added acryloyl groups in the amino-modified polyepoxide resin solution is 1000
It was 1.0 pieces per g.

Next, an amino-modified polyepoxide resin solution was prepared and Example 1
An aqueous dispersion suitable for cationic electrodeposition coating was prepared from the polyamine resin solution-1 used in Example 1 in the same manner as in Example 1, and its various coating film performances were evaluated.

The composition of the aqueous dispersion is shown in Table 1, and its cationic electrodeposition coating voltage, bath properties, and various coating film performances are shown in Table 2.

Comparative Example 2 In a reaction vessel similar to Example 1, 413 parts of polyepoxide (Yuka Shell Co., Ltd. II, Epicote $1001), 112 parts of methyl isobutyl ketone, 5 parts of a 30% methanol solution of tetramethylammonium chloride, and dimethylolpropion were added. Add 120 parts of acid, and at 110'c
6 to 110 hours to form a polyol.
After adding 7 parts of a 40% solution of p-toluenesulfonic acid (transetherification catalyst) in ethylene glycol monoethyl ether at ℃, the pressure inside the reaction vessel was reduced to about -25 to -2.
The pressure was reduced to 7 cmHg.

Then, 141 parts of N-butoxymethylacrylamide and 9 parts of a 30% solution of hydroquinone (polymerization inhibitor) in ethylene glycol monoethyl ether were added at 130 to 135°C over 1 hour.

Then, the butanol produced by the transetherification reaction was distilled off under reduced pressure for about 5 hours, and then the pressure in one reaction vessel was returned to atmospheric pressure with nitrogen gas, and then cooled and the temperature was lowered to 100 ° C. 122 parts of ethylene glycol monobutyl ether was added and the mixture was further cooled to lower the temperature to 60°C.

Next, 57 parts of dimethylamine was added over 3 hours at 60°C in the same manner as in Example 2, and then the temperature was raised to 80°C.
The reaction was carried out for 3 hours while maintaining the temperature at 0°C. Then, after stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -30 to -60.
Reduce the pressure to cdH and distill under reduced pressure at 70-90°C for 40 minutes,
After removing the unreacted amine, the inside of the reaction vessel was returned to atmospheric pressure, and a brownish-transparent solid content of 78.5% and a number average molecular weight of 1 were obtained.
600 7mino modified polyepoxide resin solution E was obtained.

Here, the number of Michael-added acrylamide groups in the amino-modified polyepoxide resin solution E is 1000
It was 1.2 pieces per g.

Next, amino-modified polyepoxide resin solution E and Example 2
An aqueous dispersion suitable for cationic electrodeposition coating was prepared from the polyamine resin solution 2 used in Example 1 in the same manner as in Example 1, and its various coating film performances were evaluated.

The composition of the aqueous dispersion is shown in Table 1, and its cationic electrodeposition coating voltage, bath properties and various coating performances are shown in Table 2.

Comparative Example 3 In a reaction vessel similar to Example 1, 436 parts of hydrogenated bisphenol A-bis-maleic acid was added under a nitrogen gas flow.

5.3 parts of dimethylethanolamine and 475 parts of methyl isobutyl ketone were charged, and the temperature was gradually raised to 70°C to dissolve them.

Then, polyepoxide (oiled shell epoxy) was heated at 70°C.
372 parts of Neopentyl Glycol Diglycidyl Ether (PG-202, manufactured by Tobu Kasei Co., Ltd.) and 300 parts of Neopentyl Glycol Diglycidyl Ether (PG-202, manufactured by Tobu Kasei Co., Ltd.) were added, and the temperature was gradually raised to 90 to 100°C, and then heated to 90 to 100 °C. After the reaction was continued for about 4 hours until the acid value became 1 or less while maintaining the temperature, 363 parts of methyl isobutyl ketone was added and immediately cooled, and the temperature was lowered to 80°C. Next, 149 parts of 2-methoxyphenylisocyanate was added at 80°C, and 149 parts of 2-methoxyphenylisocyanate was added at 80°C.
After continuing the reaction for an hour, the temperature was raised to 90°C, and the reaction was continued for an additional 0.5 hour while maintaining the temperature at 90°C.

It was then immediately cooled down to a temperature of 60°C. Next 6
Dimethylamine 2 was prepared by the same method as in Example 2 at 0°C.
After gradually putting 74 parts into the container and allowing the reaction to take place over 3 hours, the temperature was raised to 80°C, and the temperature was maintained at 80°C for an additional 3 hours.
Allowed time to react.

Then, after stopping the supply of nitrogen gas, the pressure inside the reaction vessel was reduced to -30 to -60 cmHg, and the temperature was increased to 40 cm at 70 to 90°C.
After distilling under reduced pressure for one minute to remove unreacted amine and methyl isobutyl ketone, the inside of the reaction vessel was returned to atmospheric pressure.
Ethylene glycol monoethyl ether 286 at 80°C
Add 100% of solids and stir well to obtain a brownish-transparent solid content of 82%.
．． An amino-modified polyepoxide resin solution F having a concentration of 0% and a number average molecular weight of 1,400 was obtained.

Here, the number of Michael-added ethylenically unsaturated bonds and isocyanate in the amino-modified polyepoxide resin solution F was 1.4 and 0.7, respectively, per 1000 g of the resin.

Next, amino-modified polyepoxide resin solution F and Example 1
An aqueous dispersion suitable for cationic electrodeposition coating was prepared from the polyamine resin solution-1 used in Example 1 in the same manner as in Example 1, and its various coating film performances were evaluated.

The composition of the aqueous dispersion is shown in Table 1, and its cationic luminescence coating voltage, bath properties, and various coating performances are shown in Table 2.

Comparative Example 4 In a reaction vessel similar to Example 1, 2.5-
471 parts of hexanediol-bis-maleic acid, 9.6 parts of dimethylethanolamine, and 363 parts of methyl isobutyl ketone were charged, and the mixture was gradually heated to 70°C to dissolve.

Then, polyepoxide (oiled shell epoxy) was heated at 70°C.
Co., Ltd., Epicoat #1o04) 1140 parts, polyepoxide (Yuka Shell Epoxy Co., Ltd., Epicoat #1140 parts)
1001) 588 parts, and polypropylene glycol diglycidyl ether (Tobu Kasei Co., Ltd.) 11.PG
-207) Add 377 parts and gradually raise the temperature to 90-1
After the temperature was raised to 00°C, the reaction was continued for about 4 hours until the acid value became 1 or less while maintaining the temperature at 90 to 100°C. After that, 830 parts of methyl isobutyl ketone was added and immediately cooled, and the temperature was lowered to 80°C.
lowered to

Then, 2,4-tolylene diisocyanate resin solution 558 was semi-blocked with 2-ethylhexanol at 80°C.
(mentioned above, Example 3) and 98 parts of p-ethoxyphenylisocyanate were added, the reaction was continued for 1 hour at 80°C, the temperature was raised to 90°C, the temperature was maintained at 90°C, and the temperature was further increased to 0. The reaction was allowed to proceed for .5 hours. Then cool it immediately,
The temperature was lowered to 60°C.

Then, in the same manner as in Example 2, 209 parts of dimethylamine was gradually introduced into the container at 60°C and reacted for 3 hours. Allowed time to react.

Then, after stopping the nitrogen gas supply, the pressure inside the reaction vessel was reduced to -30 to -60 cmHg, and the temperature was increased to 40 cm at 70 to 90°C.
After distilling under reduced pressure for one minute to remove unreacted amine and methyl isobutyl ketone, the inside of the reaction vessel was returned to atmospheric pressure.
Ethylene glycol monobutyl ether 662 at 80°C
Add 50% of the solids and stir well to obtain a brownish-transparent solid content of 77%.
．． An amino-modified polyepoxide resin solution G having a number average molecular weight of 0% and a number average molecular weight of zttoo was obtained.

Here, the number of Michael-added ethylenically unsaturated bonds and isocyanate in the amino-modified polyepoxide resin solution G is 0.9 each per too g of the resin.
and 0.6 pieces.

Next, amino-modified polyepoxide resin solution G and Example 1
An aqueous dispersion suitable for cationic electrodeposition coating was prepared from the polyamine resin solution-1 used in Example 1 in the same manner as in Example 1, and its various coating film performances were evaluated.

The composition of the aqueous dispersion is shown in Table 1, and its cationic electrodeposition coating voltage, bath properties, and various coating film performances are shown in Table 2.

Comparative Example 5 From amino-modified polyepoxide resin solution B and polyamine resin solution-2 used in Example 2, the resin solid content ratio of amino-modified polyepoxide to polyamine resin was 2:98 and 55:45, respectively. We prepared an aqueous dispersion suitable for cationic electrodeposition coating, and evaluated its various coating properties.

The composition of the aqueous dispersion is shown in Table 1, and its cationic electrodeposition coating voltage, bath properties, and various coating performances are shown in Table 2.

Note 1) An applied voltage that can obtain a film thickness of 20 μm by using the object to be coated as a cathode, applying electricity for 3 minutes at a bath temperature of 27°C, washing with water, and baking.

Note 2) Number of milliequivalents of acid contained in 100g of heated residue.

Note 3) Sharpen only the wood part of a pencil (Mitsubishi Uni, manufactured by Mitsubishi Pencil Co., Ltd.) and rub the lead against the painted steel plate surface at a 45 degree angle, and display the pencil hardness just before scratches appear on the painted surface. .

Note 4) Wipe back and forth 100 times with a cloth soaked in xylene, and pass if the painted surface softens and the paint film is not wiped away from the steel plate.

Note 5) According to JIS 5400. A tape peeling width from the cut part of within 3++++++ is considered acceptable.

As is clear from the results of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 2, the thermosetting coating resin compositions of Examples 1 to 3 of the present invention were sufficiently cured even when baked at 150°C for 30 minutes. It can be seen that it is possible to obtain excellent coating film quality and to have excellent bath stability, and furthermore, these coating film quality and bath stability are stably maintained over a long period of time.

On the other hand, in Comparative Example 1, which is a product of JP-A No. 55-31889, in order to obtain the same performance as the baking at 150°C for 30 minutes in Examples 1 to 3, it was necessary to This is only for the case of baking for a minute, and there is a difference of 20°C in baking temperature from Examples 1 to 3, but it can be seen that the same performance cannot be obtained even when baking at 180°C with an aqueous dispersion that has been aged. This is because the curability of the amino-modified polyepoxide resin solution used in Comparative Example 1 is inferior to the resin composition of the present invention in low temperature curability, and the remarkable increase in the amount of acid over time (Table 2) shows that. To,
This is due to hydrolysis of the Michael-added acryloyl group at the end of the resin, which is essential for imparting curability, resulting in a significant decrease in curability over time.At the same time, the pH and coating voltage also decreased, resulting in poor bath stability. It can be seen that it is severely damaged.

Similarly, Comparative Example 2, which is a product of JP-A No. 55-31889, has superior bath stability compared to Comparative Example 1, as is clear from Table 2. ℃30
To obtain performance equivalent to minute baking.

Baking for 30 minutes at 180°C or above is required, which is the same as the amino-modified polyepoxide resin solution E constituting Comparative Example 2.
This is because the low-temperature curability of the Michael-added acrylamide group in the resin side chain, which is necessary for imparting curability, is significantly inferior to that of the resin composition of the present invention, and it can be seen that the baking temperature varies by as much as 30°C.

Furthermore, in Comparative Example 2, the appearance of the resulting coating film was inferior to that of Examples 1 to 3, and this was due to the unreacted N-butoxymethylacrylamide used in the reaction during the production of amino-modified polyepoxide resin solution E. This shows that the strong acid p-toluenesulfonic acid has a large influence.

Next, in the case of Comparative Examples 3 and 4, which have different number average molecular weights from the present invention, and Comparative Example 5, which has a different ratio, the advantages of the resin compositions constituting the present invention, which are the features of the present invention, are shown in Table 2. In order to obtain coating film quality with low-temperature curability,
As can be seen from the comparison with Examples 1 to 3, it is necessary to satisfy the requirements of the present invention; otherwise, it is found that excellent coating film quality and appearance cannot be obtained.

Claims (2)

[Claims] (1) After connecting polyepoxide with an ethylenically unsaturated dibasic acid conjugated with two carbonyl groups, the ethylenically unsaturated bond and the remaining epoxy group are bonded with a boiling point of 10
Amino-modified polyepoxide 5-1 with a number average molecular weight of 1,500-10,000 obtained by adding a secondary amine at 0°C or lower
50 parts by weight, and 50 to 95 parts by weight of a polyamine resin having an amino group or an imino group. (2) The thermosetting resin composition for coating according to claim 1, wherein the amino-modified polyepoxide is an amino-modified polyepoxide in which 0.5 to 2 isocyanates per 1000 g of resin are added to the hydroxyl groups of the resin side chains. thing.