JPS59129270A - Composition for cationic electrodeposition coating - Google Patents

Abstract

PURPOSE:To provide a composition for cationic electrodeposition coating having a pH of 6 or higher and capable of forming a film with excellent rust preventive property, prepared by reacting glycidol with a reaction product obtained from an epoxy resin and a polyamine-ketimine derivative. CONSTITUTION:An epoxy resin having at least two epoxy groups (e.g. obtained by condensation of bisphenol A with epichlorohydrin) is made to react with a polyamine-ketimine derivative having secondary amino and ketimine groups. Then the ketimine group is decomposed to obtain a reaction product having at least two tertiary amino groups and at least two primary amino groups. The reaction product (A) is made to react with glycidol (B) of the formula in such a ratio that (B) may be in 0.2-2mol per mol of primary amino group of (A). The resultant amino acid-containing resin is partly neutralized to have solubility (dispersibility) in water and it is used as electrodeposition coating as it is or after blended with other amino group-containing resins.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-soluble or water-dispersible coating composition, particularly a coating composition suitable for cationic electrodeposition coating in which the object to be coated is used as a cathode for electrodeposition coating. More specifically, the present invention relates to a composition for cationic electrodeposition paint that can provide an electrodeposition paint having a pH value of 6 or more and a coating film having extremely excellent antirust properties.

Cationic electrodeposition paints have much better anti-corrosion properties than anionic electrodeposition paints, so their usage has been increasing in recent years, including in the automotive coating field.

Various proposals have been made regarding the resin composition used in this cationic electrodeposition paint, but what is actually used is an epoxy resin such as bisphenol A/epichlorohydrin condensation type epoxy resin, and primary Amine matrices are made by reacting secondary amines, adding thermosetting agents such as blocked isocyanates, and neutralizing them with acids to make them water-soluble or water-dispersible.

When such a cationic electrodeposition paint is actually used, the pH of the electrodeposition paint becomes a problem.

That is, if the pFI of the electrodeposition paint is low, it will cause serious corrosion to the electrodeposition coating equipment, resulting in accidents such as punctures in various pipes and the electrodeposition paint tank. Therefore, the pH of the electrodeposition paint is 5.0 or more, preferably 6.0.
The above is considered necessary and 1/1 le. Therefore, the amino group-containing resin used in cationic electrodeposition coating has excellent antirust properties for the coating film obtained, and at the same time, the pH of the fixing coating obtained using it is 5.0 as described above. As mentioned above, it is desirable that the value is 6.0 or more.

However, at this age, an amino group-containing resin suitable for cationic electrodeposition coating, which provides a coating film with excellent rust prevention ability and an electrodeposition coating material with a high pH, was not known.

For example, Japanese Patent Publication No. 55-34291 discloses that a cationic electrodeposition coating f1 containing an epoxy resin modified with hydroxylamine containing a primary hydroxyl group still has good rust prevention properties even without using a rust prevention pigment. However, since the basicity of the amine group of such hydroxylamine-modified epoxy resin is low, the pH of the electrodeposition paint obtained using it is low. It has the disadvantage of being low.

Further, JP-A No. 54-93024 discloses a composition for cationic electrodeposition paint that uses a resin having a primary amino group in its molecule and gives a high Even in compositions for cationic electrodeposition coatings, if the amount of resin having primary amine groups is increased until the required pH is obtained, the reaction between isocyanate groups and hydroxyl groups is more likely to occur during heat curing. The reaction between the primary amine group and the primary amine group progresses too quickly, resulting in gelation too early, which ultimately prevents the coating from completely curing and reduces its anti-corrosion ability. There is.

The present inventors have worked diligently to develop an amino group-containing resin suitable for cationic electrodeposition coating, which does not have the above disadvantages, provides an electrodeposition coating with a high pH, and provides a coating film with extremely excellent anti-corrosion properties. , conducted research and finally arrived at the present invention.

That is, the present invention provides an epoxy resin having at least two epoxy groups in one molecule, and a polyamine-ketimine derivative having one secondary amino group and at least one ketimine group in one molecule. A reaction product having at least two primary amine groups such as at least two 3-g amino groups in one molecule obtained by decomposing the ketimine group of the product obtained by reacting the ,
For cationic electrodeposition paints containing an amino group-containing resin obtained by reacting Glinodol at a ratio of 0.2 to 20 moles with respect to 1.0 mole of primary amino groups of the reaction product. The present invention relates to a composition.

Epoxy resins having at least two epoxy groups in one molecule used in the present invention include bisphenol A/epichlorohydrin condensed trapezoidal epoxy resin, bisphenol A/β-methylepichlorohydrin condensed trapezoidal epoxy resin, etc. Resins, hydrogenated bisphenol A/epichlorohydrin condensed trapezoidal epoxy (if resin, etc., diglycidyl ether of aliphatic polyether, diglycidyl ester of dicarboxylic acid, novolac type epoxy resin, etc.) are particularly preferred. For example, bisphenol A/epichlorohydrin condensation type epoxy resin (as a commercial product, for example, oil-based shell epoxy
(Epicor) 828, Epicort 1001, Epicort 1004, Epicort 1007, etc.)
etc.

These epoxy resins may be used as they are, or may be modified to contain, for example, one or two hydroxyl groups, O carboxyl groups, thiol groups, primary amine groups, etc. in one molecule.
It may be reacted with a compound containing 7 secondary amide groups to extend the molecular chain and increase the molecular weight. If the molecular weight is less than 700, the water solubility of the final cationic electrodeposition coating composition will be too high, and even if electrodeposited, the coating will run off when washed with water.
A uniform coating film cannot be obtained, and the mechanical properties and rust prevention ability of the coating film are reduced. If the number average molecular weight exceeds 8000, a stable aqueous solution or aqueous dispersion cannot be obtained unless the neutralization rate with acid is extremely increased, and the cation with a high pH, which is the object of the present invention, cannot be obtained. It is difficult to obtain an electrodeposited paint, but the melt viscosity during heating and curing becomes high, gelation is too quick, it is difficult to obtain a smooth coating, and as a result, complete curing is hindered. As a result, the anti-corrosion ability of the paint film also decreases.

Further, when the epoxy resin contains a hydroxyl group, the hydroxyl group may be reacted with a partially blocked organic polyinsyanate.

The amount of partially blocked organic polyisocyanate is not particularly limited, but usually
Preferably, consideration is given to ensuring that the amount of hydroxyl groups reacted does not exceed half of the amount of hydroxyl groups available.

This partially blocked organic polyisocyanate is obtained by reacting a part of the incyanate groups of the organic polyisocyanate with a blocking agent. It is stable at temperatures of 90 to 250 degrees Celsius.
is reactive with hydroxyl groups or amino groups and contains at least one blocked inocyanate group to about one blocked, free isocyanate group.

Partially blocked organic polyisocyanates include, for example, m-4 or p-phenylene diisocyanate, 4,4'-2 phenylmethane isocyanate, 2
, 4- or 2.6-) Aromatic or aliphatic diisocyanates such as lyre 7 diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate, etc., and ethylene glycol, fluoropylene gellicol, l-methylolpropane, etc. Blocking agents such as methyl alcohol, adducts with polyols, etc.
Aliphatic or aromatic, such as ethyl alcohol, clobyl alcohol, 7” lopyl alcohol, methyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, cyclohexyl alcohol, benzyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether alcohols and glycol ethers; 2-hydroxyethyl acrylate, 2
- Acrylic monomers containing hydroxyl groups such as hydroxyethyl methacrylate; Phenols such as phenol and cresol; 2,4- or 2,6-dolylene diisocyanate; Inphorone diisocyanates are preferred.

Suitable blocking agents include, for example, methyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, and ethylene glycol monobutyl ether.

As for the polyamine-ketimine derivative (hereinafter simply referred to as polyamine-ketimine derivative) having one secondary amine 7 group and at least one ketimine group in one molecule used in the present invention, one molecule It is derived by reacting a polyamine having one secondary amine group and at least one primary amine group with a ketone.

Here, examples of polyamines having one secondary amine group and at least one primary amine group in one molecule include ethylamine, methylaminopropylamine, and the like. A boria having one secondary amine group and one 211-class amine group;
Examples include polyamines having one secondary amino group and two primary amine groups in one molecule, such as diethylenetriamine, dipropylenetriamine, and dibutylenetriamine.

Examples of ketones include low molecular weight ketones that are easily distilled out together with water such as acetone, methyl ethyl ketone, and methyl isobutyl ketone (these are preferably used in the present invention), diethyl Jv ketone, and methyl globil ketone. Examples include ton, ethyl inpropyl ketone, cyclohexanone, cyclopentanone, and acetophenone.

The reaction resulting in the polyamine-ketimine derivative is explained as follows.

The reaction between polyamide/-ketimine derivatives and epoxy resins occurs very easily, but in that case, the ketimine groups and, if the epoxy resin contains blocked isocyanate BS, the isocyanate groups are decomposed. It is necessary that the temperature is such that no
Preferably, it is carried out at 0°C. In this case, since heat is generated, it is preferable to carry out the reaction in the presence of an organic solvent.

As the organic solvent, for example, the above-mentioned ketone is suitably used, but other hydrophilic solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate can also be used.

The product obtained by the reaction of a polyamine-ketimine derivative with an epoxy resin has at least two tertiary amine groups and at least two ketimine groups in one molecule; , by adding to the product at least an amount of water equivalent to the ketimine group.
It decomposes into a class amino group and a ketone.

The reaction product having at least two tertiary amine groups and at least two primary amino groups in one molecule obtained here, and glycidol are added to the first molecule of the reaction product.
0.2 glycidol per 1.0 mol of amino group
An amine group-containing resin can be obtained by reacting at a ratio of ~20 moles, preferably 05 to 1.5 moles.

The glycidol used here is a monoepoxy compound represented by the following structural formula, and as a commercially available product,
For example, Epiol OH manufactured by NOF ■ can be mentioned.

If glycidol is less than 0.2 mol per 10 mol of primary amino groups in the above reaction product, fewer hydroxyl groups will be introduced at the molecular ends of the resulting amino group-containing resin. And since there are many primary amine groups remaining,
Although the pH of the electrodeposition paint becomes higher, the anti-corrosion ability of the resulting paint film will decrease.If it still exceeds 20 mol, the basicity of the amino group will decrease, so the electrodeposition with a high pH will not be possible. Paint becomes difficult to obtain.

Although the reaction between glycidol and a primary amino group occurs very easily, it is preferably carried out under supervision if necessary, especially at a temperature of 50 to 130°C. In the first case, in order to avoid heat generation, glycidol was added to the organic solvent solution of the above reaction product.
The reaction may be carried out by dropping the solution over a period of 2.0 hours.

The obtained amino group-containing resin is at least partially neutralized with an acid to make it water-soluble or water-dispersible, but it may also be used alone as an electrodeposition paint, or it may contain other molecule(s). One or more resins having amino groups (hereinafter referred to as resins having amino groups) may be used in combination.

Here, the amino group-containing resin is, for example, a bisphenol A/epichlorohydrin condensation product, or this condensation product containing a hydroxyl group, a carboxyl group, a thiol group, a primary amine group, a secondary amine group, etc. Epoxy resin with epoxy/group at the end of the molecule obtained by extending the molecular chain with a compound, monoalka, nolamine 1
Examples of the resin include amino group-containing resins obtained by reacting cyanokanolamine and the like.

The mixing ratio of the amine group-containing resin and the amine group-containing resin can be arbitrarily selected as long as the resulting cationic electrodeposition coating has a p14 of 60 or more.

The composition for cationic electrodeposition coating of the present invention contains an amine group-containing resin as an essential component, and optionally contains an amine group-containing resin, and further includes resins commonly used in the technical field of cationic electrodeposition coating. , for example, organic polyisocyanates that are completely blocked with blocking agents and hydroxyl lysates that can react with incyanate groups! It may also contain a resin having the following properties and having substantially no groups that can be neutralized by acids.

Here, examples of polyynoneanate and blocking agent include the aromatic or aliphatic diisonanate mentioned above for the partially blocked polyinocyanate, and adducts of these with polyols. etc., and the blocking agent is sticky.

The amount of completely blocked organic polyisocyanate 1d1 to be added to the cationic electrodeposition coating composition of the present invention is particularly limited (c).
If the amine group-possessing resin used as necessary is reacted in advance with a partially blocked organic polyisocyanate and contains glocked ino/aito groups, the ino/aito group can be removed. It is preferred that the amount of incyanate groups including cyanate groups does not exceed the total amount of xyl # hydroxyl groups that can react with incyanate groups, and in particular,
The ratio of the total number of moles of blocked isocyanate groups to the total number of moles of hydroxyl groups is 0.1 = 10 to 1.0:
A range of 1.0 is preferred.

If the total number of moles of blocked incyanate groups is less than 0.1 with respect to the total number of moles of hydroxyl groups of 1.0, crosslinking will be insufficient and the rust-preventing ability of the resulting coating film will deteriorate. If other physical properties are insufficient and the dimension exceeds 1.0, a part of the isocyanate group cannot participate in crosslinking and remains as a substantially uncrosslinked portion, resulting in poor protection of the resulting coating film. Rust strength and other physical properties decrease.

Examples of resins that have a hydroxyl group that can react with incyanate groups and that do not have groups that can be substantially neutralized by acids include alkyl etherified melamine resins, alkyl etherified urea resins, and alkyl etherified melamine resins. Alkyl etherified amino resins such as benzoguanamine resins; phenolic resins; polyvinyl alcohol; polyvinyl butyral resins; polyethers such as polyethylene glycol and polypropylene glycol:
Examples include epoxy resins and phenoxy resins such as bisphenol A/epichlorohydrin condensation products; polyester polyols such as polycaprolactone; and polyolefin diols such as polybutageno having a hydroxyl group at the terminal, but any of these may be used within the range that does not impair the purpose of the present invention. Although it can be used, it is preferable that the amount does not exceed 20 parts by weight per 100 parts by weight of the amino group-containing resin.

The cationic electrodeposition coating composition of the present invention obtained as described above can be obtained by neutralizing the amine groups of the amino group-containing resin and the amine groups of the amino group-containing resin used as necessary with an acid. It can be water-soluble or water-dispersible.

Here, acids include carboxylic acids such as formic acid, acetic acid, propionic acid, and butyric acid; carboxylic acids such as glycolic acid and lactic acid; carboxylic acids having unsaturated groups such as acrylic acid and methacrylic acid; thioglycolic acid diphosphoric acid etc.

The amount of acid used must be at least sufficient to make the cationic electrodeposition paint composition of the present invention water-dispersible, but it must be within a range that does not result in the pH of the resulting cationic electrodeposition paint being less than 60. selected. Normally, the neutralization rate is 10-6
Achieved within 0% range.

The neutralized cationic electrodeposition coating composition obtained as described above is dissolved in water by a normal method to give a resin concentration of 1 to 30% by weight and 5 to 25% by weight in a cryophilic container. , dissolved or emulsified, and dispersed.

In that case, if necessary, hydrophilic coupling solvents, surfactants,
A catalyst can also be included in the liquid containing a surface conditioner, an antioxidant, etc. Examples of catalysts used include organic acid metal salts such as lead octylate, lead naphthenate, lead naphthenate, diptyltin silacrate, and diptyltin oxide.
Examples include organic gold) tomo compounds.

Although it is of course possible to use the composition for cationic electrodeposition paints of the present invention as it is without containing any pigment, it is also possible to use pigments commonly used in the field of cationic electrodeposition paints, such as iron oxides and lead oxides. , strontium chromate, carbon black, titanium dioxide, cadmium yellow, cadmium red, yellow lead, talc, barium sulfate, and the like.

In order to apply an electrodeposition coating made of the composition for cationic electrodeposition coating of the present invention, as in the case of the conventional cationic 1 folk coating, the coating material is used as a cathode, and in the electrodeposition coating, Soak,
Apply a voltage of 50 to 5 oov and conduct electricity for 05 to 5 minutes. Then, if necessary, excess paint adhering to the object to be coated is removed by washing with water, and then heated with a commonly used thermal heating device such as a hot air baking oven or an infrared heating lamp to form a cured coating film. The heating conditions may depend on the dissociation temperature of the blocking agent of the blocked organic polyisocyanate used, and are therefore 120 to 250°C for 1 to 60 minutes.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In the examples, parts are parts by weight, and chi is heavy equipment φ.

Example 1 (1) Synthesis of polyamine-ketimine derivative Monomethylaminopropyl 88 (10 parts amine methyl isobutyl ketone I202. and heat it while stirring (approximately 10 minutes
(0 to 110°C), the temperature was gradually increased to a state of gentle reflux at about 130°C. The reaction was continued at about 130°C for about 11 hours, and when 340 parts of distilled water was obtained, it was cooled to 40°C and a polyamine-ketimine derivative solution (non-volatile content: 88 parts) was added.
I got it.

(2) Synthesis of amine group-containing resin Epoxy resin (Yuka Cielue 7770 parts Epicoat 100 4 manufactured by Poxy ■, bisphenol A/epichlorohydrin condensed trapezoidal epoxy resin, molecular weight approximately 1800, epoxy equivalent approximately 900) Methyl isobutyl ketone 429.0 # J2 (1)
) Polyamine-Ketimi L 67. O#n derivative solution deionized water 45. OJr Glycidol (Nippon Oil Co., Ltd., 65.0# Ebiol OH
) Ethylene glycol monobutyl 200.0σ ether Based on the above formulation, the procedure was as follows.

Epoxy resin and methyl in butyl ketone are charged into a reactor equipped with a stirrer, a cooling tube, a thermometer, and a dropping tank, and the epoxy resin solution is heated and stirred (approximately 90°C). It's I.

After raising the temperature of the obtained epoxy resin solution to 80°C,
One sip of the polyamine-ketimine derivative solution of (1) above was added and reacted at 80-100°C for 2 hours.

Then, after adding deionized water, glycidol was added dropwise over 1 hour while maintaining the temperature at 100°C. Then, 1
After continuing the reaction at 10 to 120°C for 2 hours,
The temperature was raised to 30 to 140°C, and a portion of methyl isobutyl ketone was distilled off under reduced pressure. Then, ethylene glycol mobutyl ether was added to obtain a yellow transparent amine group-containing resin solution (non-volatile content: 68%).

(3) Synthesis of partially blocked organic polyinsyanate Tolylene diisocyanate 514.0 parts Methyl isobutyl ketone 130.0 #2-ethylhexylalco 356.0 N Based on the above formulation, the following procedure was carried out.

Tolylene diisocyanate and methyl isobutyl ketone were charged into a reactor equipped with a stirrer, a cooling tube, a thermometer, and a dropping tank, and heated to 5°C without stirring. While maintaining the temperature at 50°C, 2-ethylhexyl alcohol was added dropwise from the dropping tank over a period of 5 hours, and the reaction was continued for an additional hour to obtain a partially blocked organic polyisocyanate solution (non-volatile content: 87%).

(4) Synthetic epoxy resin of amino group-possessing resin (mentioned above) 900.0 parts Methyl isobutyl ketone 400.01 Partially blocked polyisocyanate solution (mentioned above) Jetanolamine 210.0 #Ethylene Glycol Mop 232.0 #Tyl Ether Based on the above formulation, the following procedure was carried out.

j'='t, f'P Epoxy resin and methyl in butyl ketone were charged into a reactor equipped with a machine, a thermometer, and a cooler, and heated (about 90°C) to obtain an epoxy resin solution.

A partially blocked organic polyisocyanate solution was added to the obtained epoxy resin solution, and the mixture was reacted at 80° C. for 2 hours. Next, add jetanolamine and reduce to 90~
After reacting at 110°C for 2 hours, the temperature was raised to 120 to 130°C, and a portion of methyl isobutyl ketone was distilled off under reduced pressure. Next, ethylene glycol monobutyl ether II + amine group-containing resin solution rL (non-volatile content 7
0chi) was obtained.

(5) Preparation of pigment-free cationic electrodeposition paint (2)
) Amino group-containing resin 5000 parts solution Above (4) amino group-containing mf resin 500.0# solution Acetic acid 20.0' deionized water
'3650. OII Based on the above formulation, the following procedure was carried out.

The amino group-containing resin of (2) above and the amine of (4) above,
% owned resin and mixed. Next, add vinegar to make the neutralization rate 40 cm.]ν (While stirring the fat mixture,
By gradually adding deionized water, a pigment-free cationic electrodeposition paint exhibiting a bright white color was obtained. The pH of the obtained cationic electrodeposition paint was 6.6.

(6) 11 (coating) Bonderite 3 is added to the cationic electrodeposition paint of (5) above.
] 1 s (+) Zinc oxide base treatment agent, manufactured by Nippon Barcalizing Qwa) treated steel plate was immersed to serve as a cathode, and 24
Electrodeposition coating was performed by applying a voltage of 0 V and energizing for 3 minutes.

Next, wash with water to remove excess paint, and bake at 170℃ for 25 minutes using a hot air drying oven to create a smooth and hard coating.
(Dry film thickness: 18 μm) was obtained.The obtained coating film was scratched with a cutter knife in two intersecting lines reaching the substrate, and the corrosion resistance was tested using a salt spray tester. As shown in Table 1, it exhibited extremely excellent rust prevention ability.

Example 2 (1) Preparation of cationic electrodeposition paint containing pigment Example 1 (2
) containing amine groups 100.0 parts (θ1 fat solution acetic acid 421 ethylene glycol monomer 20.2 parts thyl ether kaolin 100.0 carbon black 30.0 parts) Based on the above formulation, the following procedure was carried out.

The above components were placed in an attrike and dispersed for 10 hours to obtain a pigment paste. To 254 parts of the obtained pigment paste, cationic electrodeposition paint 4 containing no pigment of Example 1 (5) was added.
200 parts were gradually added while stirring (200 parts). Then,
Add deionized water (1) and cationic electrodeposition paint (containing pigment).
A solid content of 13 g) was obtained.

The pH of the obtained cationic electrodeposition paint was 68.

(2) Electrodeposition coating The cationic electrodeposition paint from (1) above was coated in the same manner as in Example 1, washed with water, and baked to form a smooth and hard coating (dry film thickness 2zμ). I got it.

The corrosion resistance of the obtained coating film was tested in the same manner as in Example 1 (7), and as shown in Table 1, it showed extremely excellent antirust ability.

Example 3 (1) Synthesis of amine group-containing resin epoxy resin (oiled shell 2100.0 parts epoxy (
4 F epicor) 10 07, bisphenol A/epichlorohydrin condensation epoxy resin, molecular weight approximately 420 J epoxy equivalent weight approximately 2100) Methyl isobutyl ketone 1 oso, o' polyamine-ketimine derivative 267. OI = Conductor solution (oiled shell epoxy (medium shock Epicure H-1, diethylenetriamine ketimine derivative solution, 171 shots 38%) deionized water 288.0" Glycidol [previous example 296.0 #1 (2) ] Ethylene glycol monobutylene 5300 parts ether Based on the above formulation, a pale yellow transparent amino group-containing resin solution (non-volatile content 68 parts) was prepared in the same manner as in Example (2).
I got it.

(2) Preparation of cationic electrodeposition paint containing pigment 300.0 parts of the amino group-containing resin of (1) above Solution possessing amino groups of Example 1 (4) 700.0 #J fat solution Polycaprolactone Trio-350 # (Plafcel P~308 manufactured by Daicel Chemical Industries @) Completely blocked organic bottle 18. Of polysocyanate solution (DC-2969 manufactured by Nippon Polyurethane, ε-caprolactam blocked product of hexamethylene diinocyanate-based organic polyisocyanate, non-volatile content 80%) Acetic acid 12.5 parts Deionized water 1920.5 & the above formulation Originally, I went to K as follows.

The amino group-containing resin solution of (1) above, the amino group-containing resin solution of Example 1 (4), polycaprolactone triol, and a completely blocked organic polyincyanate solution were mixed. Next, vinegar! After adjusting the neutralization rate to 40% by adding water to the resin mixture, deionized water was gradually added to the resin mixture while stirring to obtain a clear base (non-volatile content: 25%) that had a bluish-white color.
) was obtained.

Then, to 254 parts of the pigment paste in Example 2 (1), Clear Base 2520 AIS described in ":" was gradually added while stirring. Then, deionized water was added to obtain a cationic electrodeposition paint (solid content: 13 parts) containing a pigment.

stomach! The pH of the cationic electrodeposition paint was 6.5.

(3) Electrodeposition coating The cationic superposition paint from (2) above was electrocoated in the same manner as in Example 1, washed with water, and baked to form a smooth and hard coating (dry film thickness 18μ). Obtained.

The corrosion resistance of the resulting coating film was tested in Example 12 in the same manner as in Example 1, and as shown in Table 1, it showed extremely excellent antirust ability.

Comparative example 1 Epoxy resin [previously carried out 7765 parts Example 1 (2)
) Methyl isobutyl ketone 428.6#Example 1 (
Polyamine-173,4//ketimine derivative solution of 1) Ethylene glycol mono 7'200.0# thyl ether With the above formulation, the amino acid has a ketimine group at the end and produces 7 primary amine groups when it comes into contact with water. A resin containing the group was synthesized as follows.

Put the epoxy resin and methyl isobutyl ketone into a reactor VC equipped with a stirrer, a cooling tube, and a thermometer, and heat it (approximately 90 min.
°C) and stirred to obtain an epoxy resin solution.

After the obtained epoxy resin solution was heated to 80°C, the polyamine-ketimine derivative solution of Example 1 (1) was added, and the temperature was increased to 80°C.
After reacting at 0 to 100°C for 2 hours, 130 to 140
℃ and reduced pressure to distill off a portion of methyl in butyl ketone. Next, ethylene glycol motuptyl ether was added to the resin solution containing amine groups (non-volatile content: 7
0%) was obtained.

The obtained amino group-containing resin solution was prepared in Example 1 (5).
) A pigment-free cationic electrodeposition paint was prepared in the same manner as in Example 1 (5), except that the amino acid-containing resin was used to prepare a pigment-free cationic electrodeposition paint.
Ta. The pH of the obtained cationic electrodeposition paint was 63. The cationic direct-adhesion paint was coated with I+ (coating) in the same manner as in Example 1, washed with water, and baked. A hard but uneven coating film (dry film thickness: 20 μm) was obtained.

When the corrosion resistance of the obtained coating film was tested in the same manner as in Example 1, as shown in Table 1, the rust prevention ability was extremely poor.

Comparative Example 2 Amino group ownership in Example 1 (4) i o o o, o
Part resin solution Acetic acid 108 Deionized water
43.70. A pigment-free cationic electrodeposition paint with the above formulation was prepared as follows.

While stirring the resin solution after adding acetic acid to the amine group-possessing resin solution of Example 1 (4) to make the neutralization rate 40%,
By gradually adding deionized water, a pigment-free cationic electrodeposition paint with a bluish-white color was obtained.

The pH of the obtained cationic electrodeposition paint was extremely low at 42.

The obtained cationic electrodeposition paint was electrocoated in the same manner as in Example 1, washed with water, and baked to obtain a smooth and hard coating film (dry film thickness: 18 μm).

The corrosion resistance of the obtained coating film was tested in the same manner as in Example 1, and as shown in Table 1, the antirust ability was excellent.

Claims (1)

[Claims] A product obtained by reacting an epoxy resin having at least two epoxy groups in one molecule with a polyamine-ketimine derivative having one secondary amine group and at least one ketimine group in one molecule. A reaction product having at least two tertiary amino groups and at least two primary amine groups in one molecule obtained by decomposing the ketimine group of 02 to 2.0 glycidol per 10 moles of primary amino group
1. A composition for cationic electrodeposition coating, comprising an amino group-containing resin obtained by reaction in a molar ratio.