JPS6248720A - Production of self-curing resin - Google Patents

Abstract

PURPOSE:To obtain a self-curing resin dispersible in water, curable at a low temperature and suitable for cationic electro-deposition coating, easily, by producing a specific Michael addition product from an ethylenic unsaturated compound containing amineimide group and a primary monoamine and adding the addition product to a polyepoxide. CONSTITUTION:A self-curing resin (preferably containing 5-35wt% Michael addition product as solid) composed of a polyepoxide modified with amino group and containing amineimide group can be produced by (1) adding an ethylenic unsaturated compound containing amineimide group (e.g. 1,1,1- trimethylamine methacrylimide) with a primary monoamine (e.g. ethylamine), and (2) adding the resultant Michael addition product of formula (R1 is 2-30C alkyl, alkoxyalkyl, alkenyl, hydroxyalkyl or aryl; R2, R3 and R4 are 1-8C alkyl or hydroxyalkyl) to a polyepoxide (e.g. bisphenol A polyglycidyl ether). EFFECT:The resin gives a cured coating film having excellent pencil hardness, adhesivity and impact resistance, etc.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a method for producing a water-dispersible, low-temperature-curing self-curing resin suitable for cationic electrodeposition coating. [Conventional technology 1] Cationic electrodeposition coating has been used more and more in recent years, mainly in the automotive coating field, because it has superior rust prevention properties on the coated object compared to conventional anionic coatings. Various types of trees have been proposed for use in such cationic electrodeposition coatings, one of which is disclosed in Japanese Patent Application Laid-Open No. 60-72924. , the amine imide group is rearranged after thermal decomposition at a low humidity of 120"C or more and 170°C or less, preferably 140 to 160°C, such as introducing pendant amine imide groups to a polyamine resin having an amino group or an imino group. The tertiary amine is eliminated and isocyanate groups are generated, and the generated isocyanate groups react with hydroxyl groups, amino groups, or imino groups in the resin to form a three-dimensional N structure, resulting in an infusible and insoluble cured coating film. obtained, and the amine imide group is neutralized with acid to become an acylhydrazinium base,
This resin composition is suitable for cationic electrodeposition coating by taking advantage of the fact that a stable aqueous dispersion of a cationic resin can be obtained. Problems to be Solved by the Invention] The method for producing an amine-imide group-containing amino-modified polyepoxide (hereinafter referred to as a self-curing resin) described in JP-A-60-72924 involves, in the first step, A first monoamine or a ketimine-blocked amino group-containing polyamine is reacted to obtain a polyamine resin, and then in a second step, the polyamine resin is reacted with an ethylenically unsaturated compound having an amine imide group (hereinafter referred to as an amine imide compound). It is done by letting However, in this manufacturing process, the proportion of the polyamine resin in the first step in the self-curing resin is extremely large, so it is not possible to manufacture several batches of polyamine resin in advance using a manufacturing device with a fixed volume. First, it is necessary to produce polyamine resin for each batch. In addition, in order to obtain a polyamine resin, it is necessary to introduce into the resin a nitrogen-containing group having an active hydrogen that is capable of Michael-type addition. Blocked amino group-containing polyamines or mixtures thereof must be used. In this case, if the primary monoamine is used, it must be used in large excess to prevent gelation with the polyepoxide, and unreacted amine must be removed after the reaction. In addition, the ketimine-blocked amino group-containing polyamine does not gel at the stage of reaction with the epoxy group because it contains imino groups, but since the polyamine is used, the concentration of nitrogen-containing groups in the resin may be higher than necessary. There is a tendency for the coating film performance to deteriorate due to the increase in the amount of water. [Means for Solving the Problems J] In order to solve the above-mentioned problems, the present inventors have conducted extensive research and have produced a Michael-type adduct of an amine imide compound and a primary monoamine, Next, by adding this Michael type adduct to polyepoxide,
A self-curing resin can be easily obtained, and as a result, the manufacturing process for the self-curing resin can be simplified and shortened. At the same time, since the concentration of nitrogen-containing groups in the resin does not increase more than necessary, it is possible to easily obtain a self-curing resin. It was discovered that this did not have any adverse effect on membrane performance, and the present invention was completed. That is, this light is produced by adding a primary monoamine to an ethylenically unsaturated compound having an amine imide group to form a compound of the following general formula (wherein R1 is an alkyl group having 2 to 30 carbon atoms, an alkoxyalkyl group, an alkenyl group, a hydroxyl group). represents an alkyl group or an aryl group, and R2, R3, and R4 each represent an alkyl group or a hydroxyalkyl group having 1 to 8 carbon atoms. A self-curing resin characterized by obtaining an amino-modified polyepoxide containing an amine imide group! ! ! This is related to the 7-cent method. Examples of ethylenically unsaturated compounds having an amine imide group used in the present invention include 1,1゜1-trimethylamine methacrylimide, 1,1-dimethyl-1-ethylamine methacrylimide, 1,1-dimethyl-1-(
Examples include 2-hydroxypropyl)amine methacrylimide. Next, the primary monoamine used in the present invention has 2 carbon atoms.
-30 alkyl, alkoxylalkyl, alkenyl, hydroxyalkyl or aryl groups, such as ethylamine, propylamine, butylamine. 1-Methylbutylamine, hexylamine, 2-ethylhexylamine, 3-methoxypropylamine, 3-ethoxypropylamine, propoxypropylamine, butoxypropylamine, 2-ethylhexyloxypropylamine, decyloxypropylamine, dobucyloxy Propylamine. 1-amino-2-propene, 1-amino-2-butene,
1-Amino-2-pentene, oleylamine, 2-amine ethanol, 2-amino-1-propatol, 2,2
-dimethyl-3-amino-propatol, phenylamine, benzylamine. Examples include α-phenethylamine and β-phenethylamine. The heptanoamine undergoes Michael addition to the amine imide compound to form an imino group useful for subsequent reaction with the polyepoxide. As the amine to be added to the polyepoxide, a conventionally known secondary amine may be used in combination with the Michael type adduct obtained by adding a primary monoamine to the above-mentioned amine imide compound, if desired. Such secondary amines may have one or more imino groups in one molecule, such as diethylamine, diisopropylamine, jetanolamine, methylethanolamine, diisopropanolamine, N,
Examples include N'-dimethylenediamine, etc., and secondary monoamines and polyamines produced by blocking all amino groups with ketimine. Ketimine-blocked amine group-containing polyamines include:
For example, monomethylaminopropylamine. Diethylenetriamine, dipropylenetriamine. The amino group in polyamines such as dibuticine triamine and triethylene triamine is, for example, acetone. Examples include those converted to ketimine by reaction with ketones such as methyl ethyl ketone and methyl isobutyl ketone. Next, the polyepoxide used in the present invention is a compound having two or more 1,2 epoxy groups,
For example, polyglycidyl ethers of polyphenols can be mentioned. Here, examples of the 19-phenol include bisphenol A (2,2-bis(4-hydroxyphenyl)propane), 1,1-bis(4-hydroxyphenyl)ethane, 2-methyl-1,1-bisphenol (4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-t)
-butylphenyl)propane, bis(2-hydroxynaphthyl)methane, 1,5-dihydroxynaphthalene, and the like. Also used are, for example, oxyalkyl adducts of polyphenols such as ethylene oxide adducts and propylene oxide adducts, and polyglycidyl ethers such as novolac type phenol resins and polyphenol resins similar to these. Examples of other polyepoxides include epoxidized polyalkadiene resins, glycidyl acrylate copolymer resins, glycidyl methacrylate copolymer resins, polyglycidyl ethers of hydroxyl group-containing resins, and polyglycidyl esters of carboxyl group-containing resins. can give. The polyepoxide may be further reacted to undergo chain extension and increase its molecular weight. In this case, chain extenders include active hydrogen-containing compounds that are reactive with epoxy groups, such as glycols, diamines, polyether polyols, dimer acids, hydantoins, bisphenol A, polyaminoamides, amino acids such as hydroxyl groups, amino groups, and imino groups. Examples include compounds containing a group, a thiol group, a carboxyl group, and the like. Next, a method for producing a self-curing resin, which is a feature of the present invention, will be explained. First, in the Michael type addition reaction method between a primary monoamine and an amine imide compound, the primary monoamine and an organic solvent are placed in a reaction vessel and stirred at an appropriate temperature, preferably 70°C or higher and 120°C or lower, under an inert gas stream. while adding the amine imide compound. The reason for keeping the temperature below 120'C is to prevent thermal decomposition of the amine imide compound during the reaction.
The addition of the amine imide compound can be carried out by adding the entire amount at once, adding it in several portions, dropping it dropwise, or the like. In addition, the reaction between the amine imide compound and the primary monoamine is
Since an acylhydrazinium base whose amine imide group is neutralized with an acid is more effective in increasing the reactivity with the primary monoamine, it is preferable to carry out the reaction in the presence of an acid. The acid used for this purpose may be any conventionally known inorganic acid useful for dispersing the self-curing resin obtained in the present invention in water;
It is 0.5 to 1 mole per mole. Further, at this stage, heating, cooling, refluxing of volatile components, addition of a valve-opening solvent, etc. can be performed. After the addition of the amine imide compound is completed, the reaction is continued at an appropriate temperature and time as necessary, and then diluted with an organic solvent.
Steps such as a filtration are performed to obtain a resinous solution of the Michael adduct. Here, the organic solvent is an organic solvent used in the Michael type addition reaction between the heptanoamine and the amine imide compound and the subsequent addition reaction between the Michael type adduct and polyepoxide, and the organic solvent used in the former reaction. Examples of solvents include methyl alcohol. Alcohols such as ethyl alcohol and isopropyl alcohol, and ether alcohols such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether are preferred, and the aqueous solvent used in the latter reaction is, for example, toluene. Preferred are xylene, methyl isobutyl ketone, diisopropyl ketone, mineral spirit, ethylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, butyl acetate, and the like. Next, in the method of addition reaction between the obtained Michael adduct and polyepoxide, part or all of the polyepoxide is charged into a reaction vessel and mixed under an inert gas flow to form a uniform liquid. If necessary in this step, heating, addition of a suitable organic solvent, preliminary reaction of the polyepoxide with other components such as bisphenol A, etc. can be carried out. Next, the Michael adduct is added to the above homogeneous liquid while stirring it at an appropriate temperature and under a stream of inert gas. Michael type adducts can be added by adding the entire amount at once, dividing the amount into several parts, or adding two drops. It can be changed. At this stage, heating, cooling, refluxing of volatile components, addition of a portion of polyepoxide, a valve-opening solvent, etc. can be performed. After the addition of the Michael adduct is completed, if necessary, the reaction is continued at an appropriate temperature for 1 hour, followed by dilution with an organic solvent at 2M, filtration, etc. to obtain a self-curing resin. The proportion of the Michael type adduct in the self-curing resin is preferably 5 to 35% by weight as a solid content,
If it is less than 5% by weight, the low-temperature curability will be lost and the physical properties of the resulting coating film will be insufficient. If it exceeds 35% by weight, the electrodepositivity of the resulting aqueous dispersion and the resulting coating film will be poor. Problems arise in physical properties. Although the self-curing resin produced according to the present invention already contains an acylhydrazinium base in the resin,
Further, if necessary, the remaining amine imide group can be converted to an acylhydrazinium base by neutralizing it with an acid, and further, by diluting with water, an aqueous dispersion can be formed. Here, the acid is a paid acid or an inorganic acid, for example 9
Examples include a-acid, acetic acid, lactic acid, phosphoric acid, and the like. In addition, the proportion of acylhydrazinium base in the self-facilitating resin obtained by neutralizing the amine imide group, and the structure and molecular weight of various components will affect the dispersion stability when the self-curing resin is mixed with water. They must be mutually adjusted, taking into consideration properties such as properties, electrodepositivity, crosslinking and curing properties, and coating performance. Aqueous dispersion of self-curing resin, namely 1. By immersing the anode and the anode consisting of a conductive coating material in an IJ thione electrolyte paint bath and applying a voltage between the two electrodes, the re-electrodepositable resin is deposited as a coating film on the surface of the cathode. Such cationic electrodeposition coating techniques are well known in the art; however, ``the deposited coating film is removed from the cationic electrodeposition paint bath and then rinsed with water to the extent that it is not washed off from the surface of the object to be coated. Must have adhesive strength. The self-curing resin produced in the present invention basically consists of an amino-modified polyepoxide containing an amine imide group and an acid as a neutralizing agent, and other components include those used in ordinary cationic electrodeposition coatings. Plasticizers: surfactants; for example titanium dioxide, carbon black, tar, kaolin. Pigments such as silica, lead silicate, basic lead chromate, zinc phosphate, etc.7 extender pigments, anti-rust pigments; for example, isopropyl alcohol, butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diacetone A hydrophilic and aqueous organic solvent such as alcohol; a curing catalyst such as dibutyltin dilaurate, dibutyltin dioxide, and diphenyltin oxide; and water, etc. are appropriately added to the paint.
The resin is uniformly mixed and dispersed using a mixer or dispersion machine such as a DeSilver, homo mixer, sand grind mill, attritor, roll mill, etc. that is commonly used for JM, and the solid content of the resin is approximately 10 to 25% by weight. % cationic electrodeposition paint bath, which is an aqueous dispersion. [Example] Next, the present invention will be explained in more detail by giving examples and comparative examples. In the examples, parts are parts by weight, and % is % by weight. ◇Example 1 In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, 9 dropping funnels, and a nitrogen gas inlet, 300 parts of 2-ethylhexylamine was charged under a nitrogen gas stream, and the temperature was gradually raised to 90°C. Next, the following mixture was added dropwise over about 1 hour while maintaining the temperature at 90°C. 1.1.1-Trimetalamine methacrylimide 329
After dropping 9 parts vinegar, 111 parts 329 parts ethylene glycol monobutyl ether,
After continuing the reaction at 90°C for 2 hours, a pale yellow transparent solid content of 58
．． 8% Michael type adduct was obtained. In addition, 950 parts of polyepoxide (trade name: Epicoat 1004, manufactured by Yuka Shell Ebogishi Co., Ltd.) and 282 parts of methyl isobutyl ketone were charged in another reaction vessel similar to the above under a nitrogen gas stream, and the temperature was gradually raised to 110°C. Dissolved. Next, 369 parts of the Michael type adduct and ketimine (obtained from 1 mole of monomethylaminopropylamine and 1 mole of methyl isobutyl ketone, solid content: 9
38 parts of 0.0% methyl isobutyl ketone solution) were added and reacted for 2 hours at 90°C under a nitrogen gas stream to obtain a self-curing resin with a number average molecular ffi of 2370° and a solid content of 73.3%. 136 parts of the obtained self-curing resin was diluted with deionized water to obtain an aqueous dispersion having a resin solid content of 10%. The obtained aqueous dispersion was transferred to a polyvinyl chloride electrodeposition tank having an internal volume of about 1, the temperature was adjusted to 25° C., and a zinc phosphate treated steel plate was connected to the cathode as a coating object. Next, a carbon plate was inserted into the aqueous dispersion as an anode, and while stirring the aqueous dispersion, a direct current of 80 volts was applied for 2 minutes to perform cationic electrocoating. After washing with water, bake at 150℃ for 30 minutes, dry film thickness 19μ
A cured coating film was obtained. The test results for the cured coating film obtained are shown in Table 1 below. ◇Example 2 150 parts of 2-amino-1-propatol was charged into a reaction vessel similar to Example 1 under a nitrogen gas stream, and the temperature was gradually raised to 70°C. Next, the following mixture was added dropwise over about 1 hour while maintaining the temperature at 70°C. 1.1-Dimethyl-1-(2-hydroxypropyl)amine methacrylimide 372 parts Acetic acid
After dropping 120 parts and 372 parts of ethylene glycol monobutyl ether,
The reaction was continued for hours to obtain a pale yellow transparent Michael adduct with a solid content of 51.5%. In addition, 950 parts of polyepoxide (trade name: Ebute 1004 manufactured by Yuka Shell Epoxy Co., Ltd.) and 244 parts of methyl isobutyl ketone were charged into a reaction vessel similar to that in Example 1 under a nitrogen gas flow, and the temperature was gradually raised to 110°C. It was dissolved in Then add 506 parts of the Michael adduct,
The nitrogen gas stream was reacted at 90°C for 2 hours, and the number average molecular weight was 12380. A self-curing resin with a solid content of 71.2% was obtained. 140 parts of the obtained self-curing resin was diluted with deionized water to obtain an aqueous dispersion having a resin solid content of 10%. The obtained aqueous dispersion was subjected to cationic electrolysis IIB in the same manner as in Example 1. After washing with water, it was baked at 150° C. for 30 minutes to obtain a cured coating film with a dry thickness of 19 μm. The test results of the obtained cured coating films are shown in Table 1 below. ◇Example 3 In a reaction vessel similar to Example 1, oleylamine (trade name: Amine OB, Nippon Oil & Fats Co., Ltd.) was added under a nitrogen gas stream.
534 parts were charged and the temperature was gradually raised to 80°C. Next, while maintaining the temperature at 80°C, the following mixture was added dropwise to the mixture for about 1 hour. 1.1-Dimethyl-1-(2-hydroxypropyl)amine methacrylimide 372 parts Acetic acid
After dropping 96 parts of ethylene glycol monobutyl ether (372 parts), the reaction was continued at 80° C. for 2 hours to obtain a yellow-brown transparent Michael adduct with a solid content of 65.9%. In addition, in a reaction vessel similar to that of Example 7, under a nitrogen gas stream,
950 parts of polyepoxide (trade name Epicoat 1004 Yuka Shell Epoxy Co., Ltd.) and 244 parts of methyl isobutyl ketone were charged, and the temperature was gradually raised to 110° C. to dissolve them. Next, 687 parts of the Michael adduct was added and reacted for 2 hours at 90°C under a nitrogen gas stream to give a number average molecular fi of 2800. A self-curing resin with a solid content of 74.6% was obtained. For 134 parts of the obtained self-curing resin, dehydration,
This was diluted with water to obtain an aqueous dispersion with a resin solid content of 10%. The obtained aqueous dispersion was subjected to cationic electrodeposition coating in the same manner as in Example 1. After washing with water, bake at 150℃ for 30 minutes, dry film thickness 20μ
A cured coating film was obtained. The test results of the obtained cured coating films are shown in Table 1 below. ◇Comparative Example 1 In a reaction vessel similar to Example 1, 950 parts of polyepoxide (trade name: Epicoat 1004, manufactured by Yuka Shell Epoxy Co., Ltd.) and 336 parts of methyl isobutyl ketone were charged under a nitrogen gas flow, and the temperature was gradually raised to 110°C. Warm and dissolve. Next, 118 parts of propylamine was charged, and the mixture was reacted at 50° C. for 5 hours under a nitrogen gas stream. Then 120
The temperature was raised to 0.degree. C., and unreacted amine was removed by vigorously blowing nitrogen gas to obtain a pale yellow transparent polyamine resin with a solid content of 76.6%. The following mixture was added dropwise to the resulting polyamine resin over a period of about 1 hour while maintaining the temperature at 70°C. 1.1-dimethyl-1-(2-hydroxypropyl)amine acrylamide 138 parts ethylene glycol monobutyl ether 138 parts After dropwise addition, the reaction was continued at 70°C for 2 hours to obtain a number average molecular weight of 2200. A self-curing resin with a solid content of 72.0% was obtained. After adding 2 parts of acetic acid to 138 parts of the obtained self-curing resin and thoroughly mixing the mixture, the mixture was diluted with deionized water to obtain an aqueous dispersion having a resin solid content of 10%. The obtained aqueous dispersion was subjected to cationic electrodeposition coating in the same manner as in Example 1. After washing with water, it was baked at 150°C for 30 minutes to obtain a cured coating film with a dry film thickness of 18μ. The test results of the obtained cured coating films are shown in Table 1 below. ◇Comparative Example 2 In a reaction vessel similar to Example 1, 950 parts of polyepoxide (trade name Epicoat 1004 Yuka Shell Epoxy Co., Ltd.! 10) and 355 parts of methyl isobutyl ketone were charged under a nitrogen gas stream, and the temperature was gradually raised to 110°C. Next, 188 parts of ketimine (obtained from 1 mole of monomethylaminopropylamine and 1 mole of methyl isobutyl ketone, a solution of methyl isobutyl ketone with a solid content of 90.0%) was added, and the mixture was heated for 90 minutes under a nitrogen gas stream. The reaction was carried out at ℃ for 2 hours to obtain a pale yellow transparent polyamine resin with a solid content of 76.2%. was gradually added, and the following mixture was added dropwise over a period of about 1 hour. 1.1.1-Trimethylamine Acrylimide (128 parts) Ethylene glycol motsubutyl ether (128 parts) After dropwise addition, the reaction was continued at 90°C for 2 hours. Then, the number average molecule M 23
30. A self-curing resin with a solid content of 65.0% was obtained. After adding 2 parts of acetic acid to 154 parts of the obtained self-curing resin and thoroughly mixing the mixture, the mixture was diluted with deionized water to obtain an aqueous dispersion having a resin solid content of 10%. The obtained aqueous dispersion was subjected to cationic electrodeposition coating in the same manner as in Example 1. After washing with water, it was baked at 150° C. for 30 minutes to obtain a cured coating film with a dry film thickness of 19 μm. The test results of the obtained cured coating films are shown in Table 1 below. Further, Table 1 below shows Examples 1 to 3. The amine values, proportions in the self-curing resin, and manufacturing times of the electrodeposited coating films obtained in Comparative Examples 1 and 2 are also shown. Below margin

【Effect of the invention】

In the manufacturing process of Examples 1 to 3, since the ratio of the Michael type adduct in the self-curing resin was as small as 29.2% on average, several batches of the Michael type adduct were prepared in advance using a production device with a fixed volume. It is possible to manufacture and store the resin in bulk and use a portion each time the self-curing resin is manufactured. On the other hand, in the manufacturing process of Comparative Examples 1 and 2,
Because the proportion of polyamine resin in the self-curing resin in the first step is as high as 81.8% on average, it is not possible to manufacture several batches of polyamine resin in advance using a production device with a fixed volume, and one batch It is necessary to produce polyamine resin every minute. Therefore, in Examples 1 to 3, when producing the self-curing resin, the production time was 3 hours, making it possible to simplify and shorten the manufacturing process, whereas in Comparative Examples 1 to 2, the self-curing resin When manufacturing resin, the manufacturing time is as long as 6 to 9 hours. In addition, the resin produced according to the present invention can always keep the concentration of nitrogen-containing groups in the resin to the minimum necessary.
There is no disadvantage of increased concentration of nitrogen-containing groups leading to a decrease in coating performance. Furthermore, electrodeposition was carried out using the cationic electrodeposition paint bath obtained according to the present invention, using the conductive object as a cathode, in the same manner as ordinary cationic electrodeposition, and after rinsing with water. A cured coating is obtained by baking at 130-160°C for 20-40 minutes. The cured coating film thus obtained has a pencil hardness. Excellent in adhesion, impact resistance, flexibility, acetone rubbing resistance, water resistance, corrosion resistance, acid resistance, etc. However, in the known method of obtaining the resin by adding an amine imide compound to the polyamine resin, the cured coating film tends to be inferior in water resistance, corrosion resistance, and acid resistance due to the high amine value of the electrodeposited coating film.

Claims (1)

[Claims] 1. A primary monoamine is added to an ethylenically unsaturated compound having an amine imide group to form the following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R1 is a carbon number of 2 to 30 represents an alkyl group, an alkoxyalkyl group, an alkenyl group, a hydroxyalkyl group, or an aryl group, and R2, R3, and R4 each represent an alkyl group or a hydroxyalkyl group having 1 to 8 carbon atoms. A method for producing a self-curing resin, which further comprises adding the Michael adduct to polyepoxide to obtain an amino-modified polyepoxide containing an amine imide group. 2. The ethylenically unsaturated compound having an amine imide group is one in which part or all of the amine imide is neutralized with an organic acid or an inorganic acid. A method for producing a self-curing resin according to claim 1.