JPH01182377A - Method for cationic electro-deposition coating - Google Patents

Abstract

PURPOSE:To obtain a thick cationic electro-deposition casting film curable at a low temperature, by using a water paint containing a resin component consisting of a resin having unsaturated carbonyl group, hydroxyl group and a group containing a specific aprotic onium salt. CONSTITUTION:The paint used in the title coating process is a water paint containing a resin component consisting of a resin having alpha,beta-unsaturated carbonyl group, a primary or secondary hydroxyl group and a group containing an aprotic onium salt of formula I [R1 is hydroxyl group, alkoxyl group, ester group, 1-8C hydrocarbon group which may be substituted with halogen atom or H; R2 is H, hydroxyl group or 1-8C hydrocarbon group; -W<+> is group of formula II or formula III (Z is N or P; Y is S; R3, R4 and R5 are 1-14C organic group, etc.)]. A coating object is used as a cathode and coated with the water paint by cationic electro-deposition coating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cationic electrodeposition coating method capable of forming a thick electrodeposition coating film that can be cured by heating at a relatively low temperature.

[Prior art] Cationic electrodeposition coatings are widely used as primers for automobile bodies, one-coat finishes for various industrial equipment, etc., but generally the curing temperature of the electrodeposition coating is relatively high at 160°C or higher. It is necessary to heat it to a certain temperature. Also, when incyanate-curing type electrodeposition paint, which is the most widely used type in this field, is electrocoated, the cured film may turn yellow, and when a top coat is applied on top of the electrodeposition film, bleeding may occur in the top coat. It has drawbacks such as yellowing. Furthermore, recently, corrosion resistance performance,
In order to respond to the increasingly sophisticated requirements for paint finishes,
Electrodeposition coatings that can increase the coating thickness are desired, but with coatings that produce desorption products during curing, such as the incyanate-curing type, the applicable coating thickness is only about 50 microns. However, if it exceeds this amount, there are drawbacks such as abnormalities such as wrinkles on the painted surface and failure to obtain the expected performance due to insufficient curing.

In addition, there are electrodeposition coatings that do not produce elimination products as by-products during curing, such as polybutadiene and unsaturated fatty acid-modified resins, which are cured by oxidation or thermal polymerization, but these have poor coating performance such as corrosion resistance. There are many unsaturated groups remaining in the cured coating film, and their polymerization progresses over time, resulting in significant deterioration of the physical properties of the coating film over time.If a thick film of 50 microns or more is applied, the coating surface There is a drawback that there is a large difference in hardenability between the inside and outside, which makes it more likely that abnormalities such as wrinkles will occur on the surface.

[Problems to be Solved by the Invention] The present inventor has discovered that curing occurs at a relatively low temperature of 140°C or less, and
We are working diligently to develop a cationic electrodeposition coating method that provides electrodeposition coatings that exhibit excellent curability and appearance even in micron-thick films, as well as excellent coating performance such as water resistance and chemical resistance. I've been doing research.

[Means for Solving the Problems] As a result, the present inventor has discovered that an α,β-unsaturated carbonyl group,
By cationically electrodepositing a water-based paint whose resin component is a resin containing a primary or secondary hydroxyl group and a specific aprotic onium salt, no elimination products are produced as by-products during curing, and incyanate We have achieved a cationic electrodeposition coating method that can achieve the above objectives without causing gaps when coating a thick film as seen in hardening type, oxidation and thermal polymerization hardening types. That is, the present invention provides a resin containing an α,β-unsaturated carbonyl group, a primary or secondary hydroxyl group, and the following general formula (
An aprotic onium salt-containing group represented by -CH-CH2-We0CORI (I) [wherein R1 is a hydroxyl group, an alkoxy group, an ester group, or a carbon number of 1 to 8 which may be substituted with a halogen atom] represents a hydrocarbon group or a hydrogen atom; R2 represents a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 8 carbon atoms;
@-R, or Rs R4 ■ -YΦ, where Z is a nitrogen atom or a phosphorus atom, and Y
represents a sulfur atom* R3, R4 and R.

are the same or different and represent an organic group having 1 to 14 carbon atoms, and R3 and R4 or R3,R.

and R3 may be taken together to form a heterocyclic group together with the nitrogen atom, phosphorus atom, or sulfur atom to which they are bonded. The present invention relates to a cationic electrodeposition coating method, characterized in that the electrodeposition coating is carried out by using a cathode as a cathode.

In the resin of the present invention having an α,β-unsaturated carbonyl group, a primary or secondary hydroxyl group, and an aprotic onium salt-containing group represented by the general formula (I), the α,β-unsaturated 1, such as acryloyl group, methac, lyloyl group, itaconate group, maleate group, fumarate group, crotonate group,
Examples include a cinnamic acid group, an acrylamide group, and a methacrylamide group.

The aprotic onium salt-containing group represented by the following general formula (I) in the resin is -CH-CH2-W''0COR1(I) [Rs and R2 are as described above] The onium salt is a quaternary ammonium salt, It has either a quaternary phosphonium salt or a tertiary sulfonium salt, and specific examples of cations in these salts are shown below.

R2R4 words R2H.

R2R4 [In each of the above formulas, R2 represents a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 8 carbon atoms, R3゜R4 and R,
The same or different represents an organic group having 1 to 14 carbon atoms, and these R3 and R4 or R,, R, and R6 together represent the nitrogen atom, phosphorus atom, or sulfur atom to which they are bonded. The hydrocarbon group having 1 to 8 carbon atoms in R2 in each of the above formulas is preferably an alkyl group or alkenyl group having 1 to 8 carbon atoms. eR2 is a group having 1 to 8 carbon atoms. Although a hydrogen atom or a hydroxyl group may be used in addition to the hydrocarbon group in No. 8, a hydroxyl group is particularly preferred from the viewpoint of curability.

The organic groups having 1 to 14 carbon atoms represented by R3, R, and R5 are not particularly limited as long as they do not substantially interfere with the ionization of ammonium bases, phosphonium bases, or sulfonium bases, such as hydroxyl groups, alkoxy A hydrocarbon group having 1 to 14 carbon atoms which may contain a heteroatom such as an oxygen atom in the form of a group or the like is generally used.

Examples of such hydrocarbon groups include aliphatic, alicyclic, or aromatic hydrocarbon groups such as alkyl groups, cycloalkyl groups, cycloalkylalkyl groups, aryl groups, and aralkyl groups. The above-mentioned alkyl group may be either linear or branched, and has 8 or less carbon atoms, preferably a lower one, such as methyl, ethyl, n- or 1so-propyl, n- 11so-1111aC-
Alternatively, examples include tert-butyl, pentyl, heptyl, octyl groups, and the like. The above-mentioned cycloalkyl group or cycloalkylalkyl group preferably has 5 to 8 carbon atoms, such as cyclopentyl, cyclohexyl,
Examples include cyclohexylmethyl and cyclohexylethyl groups. The above aryl group includes phenyl, tolyl,
Xylyl groups and the like are included. Furthermore, a benzyl group is suitable as the aralkyl group.

A preferred example of a hydrocarbon group containing a different atom, such as an oxygen atom, is a hydroxyalkyl group (particularly a hydroxy lower alkyl group).

Specifically, hydroxymethyl, hydroxyethyl, hydroxybutyl, hydroxypentyl, hydroxyheptyl, hydroxyoctyl groups, etc., alkoxyalkyl groups (especially lower alkoxy lower alkyl groups), specifically methoxymethyl, ethoxymethyl, ethoxyethyl, n-
Propoxyethyl, 1so-propoxymethyl, n
-butoxyethyl, 1so-butoxyethyl, tsr
Examples include j-butoxyethyl group.

R2 and R3 or R2, R3 and R4 together,
-W11) when these are heterocyclic groups formed together with the nitrogen atom, phosphorus atom or sulfur atom to which they are bonded
Examples of this include those shown below.

The anion in the above onium salt is 0COR.

[In the formula, R8 represents a hydrocarbon group having 1 to 8 carbon atoms or a hydrogen atom which may be substituted with a hydroxyl group, an alkoxy group, an ester group, or a halogen atom.] Examples of the hydrocarbon group of 8 include carbon, aliphatic groups such as alkyl groups of 1 to 8 atoms, alkenyl groups, cycloalkyl groups, cycloalkenyl groups, aryl groups, and aralkyl groups.

Examples include alicyclic or aromatic hydrocarbon groups. Among these, alkyl groups and alkenyl groups are preferable, and these groups may be either linear or branched, and lower groups are particularly preferable, such as methyl, ethyl, n-
or 1so-propyl, n-, 1so-, sec
- or tert-butyl, pentyl, heptyl, octyl, vinyl, and methyl group-substituted vinyl groups. Preferred examples of the hydroxyl-substituted hydrocarbon group include hydroxyalkyl groups (particularly hydroxy lower alkyl groups), specifically hydroxymethyl, hydroxyethyl, hydroxybutyl, hydroxypentyl, hydroxyheptyl, hydroxyoctyl groups, and the like. Preferred examples of alkoxy-substituted hydrocarbon groups include alkoxyalkyl groups (especially lower alkoxy-lower alkyl groups), specifically methoxymethyl, ethoxymethyl, nidoxyethyl, n-propoxyethyl, igo-propoxyethyl, n-butoxy Examples include methyl, 1so-butoxyethyl and tert-butoxyethyl groups. A preferred example of the ester group-substituted hydrocarbon group is a lower alkyloxycarbonyl alkyl group.

Lower alkyloxycarbonylalkenyl groups, specifically methyloxycarbonylmethyl, propyloxycarbonylethyl, ethyloxycarbonylpropyl, methyloxycarbonylbutyl.

Examples include methyloxycarbonylbutylnyl and ethyloxycarbonylethylenyl groups. Preferred examples of the halogen atom-substituted hydrocarbon group include lower halogenated alkyl groups, specifically methyl monochloride group, -methyl bromide group,
- methyl iodide group, methyl dichloride group, methyl trichloride group,
Examples include -ethyl chloride group and -butyl chloride group.

Examples of the organic carboxylic acids used to generate the above anions include acetic acid, formic acid, trimethylacetic acid, acrylic acid, methacrylic acid, lactic acid, hydroxyacetic acid, crotonic acid, chloroacetic acid, maleic acid monomethyl ester, and fumaric acid monomethyl ester. Examples include ethyl ester and monomethyl itaconate. Among these, the dissociation constant (pKa
A value of i x l 04 or more is preferable. By using onium salts of these #1 acids, sufficient performance can be obtained in terms of the curability of the electrodeposited coating film and the water resistance of the cured electrodeposition coating film.

In the present invention, the above-mentioned resin includes an α, β-unsaturated carbonyl group, a primary or secondary hydroxyl group, and the general formula (
As long as the resin has an aprotic onium salt-containing group represented by 1), it may be any conventionally known resin such as acrylic, polyester, urethane, alkyd, epoxy, or phenol, and is not particularly limited. The molecular weight of the resin is not particularly limited, but the peak molecular weight by GPC is 250 to 100,000.
degree is preferable, and about 500 to 20,000 is more preferable.

In the resin, the α,β-unsaturated carbonyl group is 0.1 to 10 mol, more preferably 0.5 to 10 mol per IKg of resin.
It is appropriate that the amount of the primary or secondary hydroxyl group is within the range of 5 mol, and it is appropriate that the primary or secondary hydroxyl group is 0.1 mol or more, more preferably within the range of 0.5 to 10 mol. . When the amount of α, β-unsaturated groups and primary or secondary hydroxyl groups is less than the above range, curability tends to decrease. The amount of onium salt-containing groups in the resin is preferably 0.01 to 5 mol per IKg of the resin, more preferably 0.1
It is appropriate that the amount is within the range of 1 mol.

The introduction of α,β-unsaturated carbonyl group into the above resin is as follows:
A functional group that reacts with a functional group in the resin and α.

Compounds with β-unsaturated carbonyl groups (resins, resins)
For example, (1) Addition reaction between a carboxyl group and an epoxy group (2) Addition reaction between a hydroxyl group and an epoxy group (3) Addition reaction between a phenolic hydroxyl group and an epoxy group (4)
) Esterification reaction between a hydroxyl group and a carboxyl group (5) Half-esterification between a hydroxyl group and an acid anhydride (6) Transesterification reaction between a hydroxyl group and an ester group (7) Utilizing an addition reaction between an incyanate group and a hydroxyl group, etc. It can be done.

Further, the onium salt-containing group can be introduced into the resin by, for example, the method shown in (i) or (ii) below.

(il) After reacting a resin having a halogenated alkyl group with a tertiary amine, phosphine or thioether in a solvent-free or inert organic solvent, the halogen atom is replaced with a hydroxyl group by anion exchange, and then the halogen atom is replaced with a hydroxyl group by anion exchange. A method of reacting organic acids.

Taking as an example a case where a tertiary amine is used as a compound to be reacted with the resin, the reaction formula is as follows.

Suga R2R4 R2R4 [In the formula, [F] represents the base portion of the resin, and X represents a halogen atom* R2, R3, R4 and R3 are the same as above,
] When using a phosphine instead of a tertiary amine, it is sufficient to replace N with P in the above reaction formula, and also use a tertiary amine.
When a thioether is used instead of a primary amine, N may be replaced with S and -R5 may be deleted in the above reaction formula.

The reaction between the above resin and tertiary amine etc. is approximately 100 to 15
The reaction is carried out under heating at 0° C. and is completed in about 1 to 20 hours.

In order to anion-exchange the above reaction product and react with an organic acid to obtain an onium salt of the organic acid, for example, the reaction product is passed through a bead-type anion exchange resin to replace the halogen with a hydroxyl group. , and then mix this with an organic acid.

(-1) In no solvent or in an inert organic solvent, l, 2
- A method in which a resin having an epoxy group is simultaneously reacted with a tertiary amine, a phosphine or a thioether, and an organic acid.

Taking as an example a case where a tertiary amine is used as a compound to be reacted with the resin, the reaction formula is as follows.

0 Ra OHRa [In the formula, R1, R3, Rs, Rs and [F] are the same as above] Using phosphine in place of the tertiary amine 1. %, and 1,000 onythyl is used in place of the tertiary amine.

In this case, as in the case (1) above, N in the above reaction formula is replaced with P, or N is replaced with S and -
Just delete R5.

The reaction of the above resin, tertiary amine, etc. and organic acid takes about 40 minutes.
The reaction is carried out under heating at ~80°C and is completed in about 1 to 20 hours.

Examples of inert organic solvents used in (1) and (11) above include ether alcohol solvents such as ethylene glycol monobutyl ether and ethylene glycol monoethyl ether, ether solvents such as dioxane and ethylene glycol diethyl ether, ethanol, Examples include alcohol solvents such as propatool and butanol, and ketone solvents such as methyl ethyl ketone and methyl butyl ketone.

In addition, when the resin is an acrylic resin, the onium salt can be introduced into the resin according to the methods (i) and (11) above, but the following general formula [wherein R8 represents a hydrogen atom or a methyl group] .

R1 and We are the same as above.] It can also be carried out by polymerizing a (meth)acrylic acid ester monomer represented by the above alone or together with a comonomer copolymerizable therewith in accordance with a conventional method.

The resin obtained as described above contains an onium salt and therefore has surface active ability by itself, and can be dissolved in water by adding water to the resin or blending the resin into water. The destination may be dispersed.

In addition, in order to improve water dispersibility, the resin may contain about 0.2 to 1.5 moles of tertiary amino groups per resin IK, if necessary. The introduction of is, for example, (1) an addition reaction between an epoxy group and a secondary amine, (2) an addition reaction between an epoxy group and a tertiary alkanolamine, (3) an addition reaction between an isocyanate group and a tertiary alkanolamine, and (4) a carboxyl Esterification reaction between a group and a tertiary alkanolamine (5) This can be carried out using an addition reaction between an unsaturated group and a secondary amine. When the resin contains tertiary amino groups, all or part of them can be neutralized with an organic acid and dissolved or dispersed in water, if necessary.

In this way, the water-based paint of the present invention is obtained, and the water-based paint contains coloring pigments, extender pigments, anti-rust pigments, dyes,
A pigment dispersion resin, a pigment dispersant, a leveling agent, an antifoaming agent, an anti-sagging agent, a solvent, etc. may be added.

There are no particular restrictions on the solvent/binding agent as long as it can be used in cationic electrodeposition paints, but examples include impropatol, alcohols such as butanol, monoalkyl ethers of ethylene glycol, and monoalkyl propylene glycols. Ethers, monoalkyl ethers of diethylene glycol, monoalkyl ethers of dipropylene glycol, dialkyl ethers of ethylene glycol, dialkyl ethers of diethylene glycol, cyclic ethers such as dioxane, etc., against water at 25°C. It is preferable to use a solvent that dissolves 5% or more in the range of 0 to 100 parts by weight based on 100 parts by weight of the solid content of the bath. Alcohols, octoxyethanol, etc., ethylene glycol, propylene glycol, diethylene glycol,
Mono- and di-ethers such as dipropylene glycol with a solubility in water at 25°C of less than 5%, aromatic, aliphatic, alicyclic hydrocarbons, and ketones have a bath solid content of 1
It is preferable to use it in a range of 0 to 20 parts by weight per 00 parts by weight.

In addition, there are no particular restrictions on the amount or type of pigments and additives that can be used in cationic electrodeposition paints, but pigments may be used in the present invention from the viewpoint of bath stability. The solid content of the water-based paint is preferably within 50% by weight.

The solid content of the water-based paint obtained as described above can be varied depending on the required coating film thickness and coating conditions, but usually,
The bath has a solid content of 1 to 30% and is used for cationic electrodeposition coating using the object to be coated as a cathode.

As the electrodeposition coating conditions, the conditions generally used in the past can be applied, and a predetermined voltage (usually 10 to 500 volts) is applied between the conductive coating material as a cathode and a counter electrode for a predetermined period of time (usually 30 seconds). ~10 minutes) After application, the object to be coated is taken out of the bath and heated to 80°C or higher, preferably 100°C or after washing with water.
℃ or more, more preferably about 120 to 200℃, preferably 5 minutes or more, more preferably lθ to 30 minutes, the objective of the present invention is to achieve a good coating film appearance and good coating performance. Excellent electrodeposited coatings can be obtained. In addition, by adjusting the electrodeposition conditions, it is possible to obtain an electrodeposition coating film with a thickness of about 50 to 100 microns, and even with such a thick film, there are no problems with the coating surface due to abnormalities in the coating surface, poor curing during baking, or cracks. It is possible to obtain a good thick cured electrodeposited coating without yellowing or yellowing.

In addition to the above-mentioned so-called constant voltage oil, electrodeposition coating methods include the so-called slow start method, in which the voltage is started from Ov and gradually increased to a constant voltage, and electrodeposition is carried out for a predetermined time; Electrodeposition coating can also be suitably carried out by a constant current method in which the current is applied, or by a mode in which these methods are mixed.

In the present invention, although the curing reaction mechanism of the electrodeposition coating film by heating is not clear, the disappearance of unsaturated groups is observed in changes in the infrared absorption spectrum, and this is due to the polymerization of polymerizable unsaturated groups or to the formation of polymerizable unsaturated groups. This is thought to be due to the addition reaction of active hydrogen such as hydroxyl groups.

Furthermore, during this heating, in addition to the hardening and curing reactions, Hofmann decomposition of the onium salt in the resin occurs to improve water resistance.

[Action and Effects of the Invention J] In the present invention, a specific aprotic onium salt contained in the resin (1) enables water solubilization and water dispersion of the resin, (2) acts as a catalyst during crosslinking and curing of the coating, ■Hoffmann decomposition easily occurs when the coating is crosslinked and cured by heating.
Onium salt is no longer contained in the cured coating, and as a result, a cured electrodeposited coating with excellent properties such as water resistance and chemical resistance can be obtained by heating at a relatively low temperature.

Furthermore, the present invention makes it possible to obtain an electrodeposited coating film that exhibits excellent curability, good coating appearance, and excellent coating performance even at a thickness of 50 to 100 microns, which could not be obtained using conventional electrodeposition coating methods. can.

Tsumae Examples are given below to further clarify the present invention.

Note that "1 part" and "%" mean "part by weight" and "% by weight," respectively.

Production Example 1 90% ethylene glycol diethyl ether in a flask
parts were blended and maintained at 110°C. Styrene 2 in this
0 parts, 2-hydroxyethyl methacrylate 10 parts, butyl acrylate 35 parts, glycidyl methacrylate 3 parts
A mixture of 5 parts and 3 parts of t-butylperoxyoctoate was added dropwise over 3 hours, and the mixture was further aged at 110°C for 7 hours. Acrylic on this one! ! 8 parts, 0.1 part of methoxyhydroquinone and 0.2 parts of tributylamine.
After adding 1.0 parts of N-methylethanolamine and reacting at 110°C for 5 hours, the mixture was cooled to 50°C, 8.9 parts of N-methylethanolamine was added, and the reaction was carried out at 30°C for 8 hours. 1 part and 1.5 parts of dimethylaminoethanol were added, and the reaction was carried out at 70°C for 4 hours. The obtained resin solution (a, -1) has a nonvolatile content of 66%, and this resin (a, -1) has a nonvolatile content of 66%.
Solid content) α,β-unsaturated carbonyl group concentration 0.93 mol/Kg, hydroxyl group concentration 3.2 mol/Kg, quaternary ammonium salt concentration 0.14 mol/Kg, tertiary amine group concentration 1
．． 0 mol/Kg and peak molecular weight by GPC of 13
It was 000.

Production Example 2 90% ethylene glycol diethyl ether in a flask
parts were blended and kept at 80°C. In this, 17.4 parts of dimethylaminoethyl methacrylate, 20 parts of styrene,
37.6 parts of n-HMA, 25 parts of glycidyl methacrylate
3 parts of azobisisovaleronitrile and 5 parts of azobisisovaleronitrile.
After dropping over a period of time, the temperature was maintained at 80°C for 1 hour, and a solution of 0.5 parts of azobisisovaleronitrile dissolved in 10 parts of ethylene glycol monoethyl ether was added dropwise over a period of 1 hour. After further reacting at 80°C for 5 hours, 12.5 parts of acrylic acid, 0.1 part of tetramethylammonium chloride, and 0.05 parts of hydroquinone were added to this mixture, and the mixture was reacted at 100°C for 5 hours. Cool to 50°C and add butylene oxide 3
．． 6 parts and 3 parts of acetic acid were added and the reaction was carried out at 50°C for 8 hours to obtain a resin solution (a-2) with a solid content of 57%. This resin (solid content) has an acid value of 0.3, an α,β-unsaturated carbonyl group concentration of 1.5 mol/Kg, and a hydroxyl group concentration of 1.5 mol/K.
g, quaternary ammonium salt concentration 0.42 mol/Kg, tertiary amine group concentration 0.59 mol/Kg.

The peak molecular weight by L/Kg and GPC is approximately 4200.
It was 00.

Production Example 3 In a flask, 500 parts of 2 pico-) $152 (novolac phenolic epoxy resin, epoxy equivalent 173, manufactured by Yuka Shell Epoxy Co., Ltd.).

115 parts of dibutylamine, 0.5 parts of hydroquinone and 200 parts of 2-methoxypropanol were mixed and reacted at 80°C for 2 hours with stirring, then 144 parts of acrylic acid was added and reacted at 100°C for 4 hours. . Furthermore, 14.4 parts of butylene oxide and 12 parts of acetic acid were added to this product.
．． Add 0 parts and react at 70°C for 5 hours to reach a solid content of 80%.
A resin solution (a-3) was obtained. This resin (solid content) is α
, β-unsaturated carbonyl group concentration 2.6 mol/Kg, hydroxyl group concentration 3.7 mol/Kg, quaternary ammonium salt concentration 0.
26 mol/Kg, tertiary amide 7 group concentration 0.89 mol/Kg
And the peak molecular weight by GPC was about 780.

Production Example 4 In a flask, 300 parts of Epicoat #1001 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 950), 200 parts of Epicoat #1001 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 450), and 200 parts of methyl isobutyl ketone were placed in a flask. After blending and uniformly dissolving, 0.1 part of dibutyltin laurate and 0.5 part of hydroquinone were added and kept at 80°C, and the adduct of tolylene diisocyanate and 2-hydroxyethyl acrylate ( 1 mole: 203 parts of 1 mole adduct)
The mixture was added dropwise over a period of time, and after the completion of the addition, the reaction was continued at 80° C. for an additional 5 hours. Next, 21.6 parts of acrylic acid and 0.3 parts of tetraethylammonium bromide were added to this, and after reacting at 110°C for 5 hours, it was cooled to 70°C, and further 56.1 parts of thiodiglycol and 27.5 parts of acetic acid were added. The mixture was added and reacted at 70°C for 8 hours to obtain a resin solution (a-4) with a solid content of 80%. This resin (solid content) has an α,β-unsaturated carbonyl group concentration of 1.2 mol/Kg and a hydroxyl group concentration of 1.2 mol/Kg.
4 mol/Kg, tertiary sulfonium salt concentration 0.57 mol/
The peak molecular weight by Kg and GPC was approximately 1750.

Production Example 5 In a flask, 300 parts of Epikote #152 (above), 300 parts of Epicoat #1001 (above), 34.6 parts of jetanolamine, 0.5 part of hydroquinone, and 200 parts of 2-butoxycetanol were mixed and heated at 70°C. After reacting for 4 hours, 137 parts of acrylic acid was added and the reaction was carried out at 90°C for 6 hours.Next, 17.2 parts of triethylamine and 16.7 parts of lactic acid were added to this mixture at 50°C for 8 hours. The reaction was carried out to obtain a resin solution (a-5) with a solid content of 80%. This resin (solid content) has an α,β-unsaturated carbonyl group concentration of 2.4 mol/Kg and a hydroxyl group concentration of 6.
．． 3 mol/Kg, quaternary ammonium salt concentration 0.21 mol/Kg, tertiary amine group concentration 0.41 mol/Kg and G
The peak molecular weight determined by PC was 1000.

Production Example 6 Epicor) #152 (above) soo part in a flask,
Hydroquinone 0.5 part, 2-methoxypropertool 3
00 parts, 1.0 part of tetraethylammonium chloride, and 186 parts of acrylic acid were mixed, and the mixture was reacted at 110°C for 4 hours. Furthermore, 81.3 parts of triphenylphosphine and 18.6 parts of acetic acid were added to this and the reaction was carried out at 80"0 for 5 hours to obtain a resin solution (a-6) with a solid content of 73%. This resin (solid content ) has an α, β-unsaturated carbonyl group concentration of 3.3 mol/Kg and a hydroxyl group concentration of 3.5 mol/Kg.
, a quaternary phosphonium salt concentration of 0.38 mol/Kg, and a peak molecular weight of 800 by GPC.

Comparison, Production Example 1 (Production of resin not containing onium salt) Ethylene glycol monobutyl ether 6 in a flask
0 parts was blended and maintained at 110°C. In this, 20 parts of methyl chloride, 10 parts of 2-hydroxyethyl methacrylate,
A mixture of 35 parts of butyl acrylate, 35 parts of glycidyl methacrylate, and 3 parts of t-butyl peroxyoctoate was added dropwise over a period of 3 hours, and an additional 7 parts of the mixture was added at 110°C.
Aged for time. This was cooled to 50°C, 10.5 parts of jetanolamine was added, and after reaction at 50 to 70°C for 2 hours, 10.5 parts of acrylic acid and 0.2 parts of hydroquinone were added.
The mixture was heated to 110°C and reacted at this temperature for 4 hours. The obtained resin solution (c-1) has a nonvolatile content of 67%, and this resin (solid content) has an acid value of 0.5, an α,β-unsaturated carbonyl group concentration of 1.2 mol/Kg, and a hydroxyl group concentration. 4.
3 mol/Kg, tertiary amine group concentration 0.83 mol/Kg, and peak molecular weight by GPC of about 12,000.

Comparative Production Example 2 (Production of resin not containing onium salt) In a flask, 500 parts of Epikote #152 (novolac phenol type epoxy resin, epoxy equivalent 173, product of Yuka Shell Epoxy Co., Ltd.), 110 parts of dibutylamine, and 0.0 parts of hydroquinone were placed. 5 parts of 2-methoxypropanol and 200 parts of 2-methoxypropanol were mixed and reacted at 80°C for 2 hours with stirring, and then 144 parts of acrylic acid was added and the mixture was heated to 110°C.
A resin solution with a solid content of 79% (c-2) was reacted for 4 hours.
I got it. This resin (solid content) has an acid value of 0.8, an α,β-unsaturated carbonyl group concentration of 2.6 mol/Kg, and a hydroxyl group concentration of 3.
．． 8 mol/Kg, tertiary amine group concentration 1.2 mol/Kg
And the peak molecular weight by GPC was about 900.

Example 1 100 parts of the resin solution (a-1) obtained in Production Example 1, 20 parts of rutile-type titanium dioxide, and 1 part of ethylene glycol monon-hexyl ether were mixed, and the mixture was milled in a pebble ball mill until the lumps on a lump gauge were 7-101L
It took 24 hours for zero dispersion. Stir this dispersion at high speed @ (800-1000
331 parts of deionized water and 0.0 parts of acetic acid in a stirrer (rpm).
A stable aqueous paint dispersion was obtained by gradually adding the mixture with 5 parts.

Using this aqueous paint dispersion as an electrodeposition bath, cationic electrodeposition coating was carried out at a bath temperature of 28±1° C. and a zinc phosphate-treated steel plate as an object to be coated at 200V for 3 minutes. The electrodeposition coated plate was then washed with water and then baked and cured at 140°C for 20 minutes. The performance of the obtained cured coated plate is shown in Table 2.

Examples 2 to 6 and Comparative Examples 1 to 2 In the same manner as in Example 1, aqueous paint dispersions were prepared using the formulations shown in Table 1. Cationic electrodeposition coating and baking were then carried out in the same manner as in Example 1 under the conditions shown in Table 2. The performance of the obtained cured coated plate is shown in Table 2.

Comparative Example 3 100 parts of 72% polyamide-modified epoxy incyanate curing type cationic electrodeposition coating (Nileclone #9200 Clear Kansai Paint ■) and 0 parts of carbon black
．． After adding 5 parts of talc, 5 parts of benzyl alcohol, and 1 part of benzyl alcohol and dispersing in a ball mill for 36 hours, 106.5 parts of the dispersion was mixed with 409 parts of deionized water stirred with a high-speed disper (800 to 1000 rpm) and 1 part of acetic acid. 5 parts to obtain an aqueous paint dispersion.

Electrodeposition coating and baking were carried out in the same manner as in Example 1 except that the aqueous paint dispersion was used as an electrodeposition bath and the electrodeposition conditions were 250V for 3 minutes to obtain a cured coated plate. The performance of the obtained cured coated plate is shown in Table 2.

Comparative Example 4 A cured coated plate was obtained in the same manner as in Comparative Example 3 except that the electrodeposition coating was performed at 350 V for 6 minutes. The performance of the obtained cured coated plate is shown in Table 2.

The tests in Table 2 were conducted according to the following method.

(*1) IilFt bankability: JIS K5400-1
979 6.13.3 Indicates the maximum height without causing paint film damage using a weight of 500 g and a center of impact tip diameter of inches in an atmosphere of 20°C, 50
Both the 0 surface (concave portion) and the lining (convex portion) were evaluated with cm being the highest value.

(Thursday 2) Adhesion: JIS K5400-1979
s, tsi 7) Make 100 strips of paint film, apply adhesive cellophane tape to its surface, and record the number of strips of paint remaining on the painted surface after rapidly peeling it off. did.

(Tree 3) Boiling water resistance: After immersing the coated plate in boiling water for 1 hour, the coated plate was left to stand for 24 hours, and then the same test as in (*2) Adhesion was conducted on the coated plate.

(Tree 4) Salt spray resistance: Make cross-cut scratches on the coating film with a knife to reach the substrate, and then
A salt spray test was conducted using No. 22371, and the time required for the maximum blistering width or creep width on one side of the crosscut to reach 3 layers was recorded.

(Thursday 5) Pour the test paint into a stainless steel cylindrical container up to 27cs+ from the bottom, maintain it at 28±1°C, and stir evenly. Next, the inner diameter 16s layer φ and the thickness I
g+■, 1 inside the stainless steel pipe with a height of 3001
Attach an inner plate of 5X300X0.4+u+ and place the pipe vertically into a stainless steel cylindrical container, 20+++s from the bottom.
Set them apart. Paint voltage from 0 to 20 in 10 seconds
Increase to 0V. (At this time, adjust the rising speed so that the current does not exceed IOA.) After 3 minutes of energization, turn off the switch, wash the inner plate and pipe with water, and then bake dry the inner plate. Measure the height to the tip of the inner plate where the paint is attached,
This value is displayed. The larger this value is, the better the throwing power is.

(Zero 6) Gel fraction: The free coating film was immersed in 77 tons of water at about 57°C (under reflux) for 4 hours to perform extraction.

(Thursday 7) Bath stability: Bath paint 1 stirred for 2 months at 30°C
When the text is filtered through a 400-mesh wire mesh, the remaining liquid is 1
Weight when dried at 20℃ for 1 hour (eg/exchanged paint)
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Claims (1)

[Claims] (1) The resin contains α,β-unsaturated carbonyl groups, primary or secondary hydroxyl groups, and aproton-type onium salt-containing groups represented by the following general formula (I)▲Mathematical formulas, chemical formulas, tables, etc.▼( I) [In the formula, R_1 has 1 to 1 carbon atoms, which may be substituted with a hydroxyl group, an alkoxy group, an ester group, or a halogen atom.
R_2 represents a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 8 carbon atoms. -W^
■There are ▲mathematical formulas, chemical formulas, tables, etc.▼ or ▲mathematical formulas,
There are chemical formulas, tables, etc. Showing ▼. Here, Z represents a nitrogen atom or a phosphorus atom, and Y represents a sulfur atom. R_3, R_4
and R_5 are the same or different and represent an organic group having 1 to 14 carbon atoms. Also, these R_3 and R_4 or R_3,
R_4 and R_5 may be taken together to form a heterocyclic group together with the nitrogen atom, phosphorus atom or sulfur atom to which they are bonded. ] A cationic electrodeposition coating method characterized by electrodeposition coating using a water-based paint containing a resin having the following as a resin component, with the object to be coated serving as a cathode.