JPH03185079A - Cationic electrodepositing paint - Google Patents

Abstract

PURPOSE:To obtain the subject paint quickly curing cationic electrodeposited coated film with crosslinking and imparting excellent flatness and stability to coated film containing lead maleate. CONSTITUTION:For instance, 0.5-10wt.% (to solid component of resin) lead maleate expressed by formula II (granular or powdery at room temperature) is contained in a cationic electrodepositing paint preferably composed of main resin containing 20-200 (hydroxyl group value) primary hydroxyl group and 8-80 [KOH (mg/g solid component)] cationic group as principal components and curing agent such as epoxy resin containing 2-30 pieces of structural unit expressed by formula I, and colored pigment or dispersant, etc., is added, as necessary, to afford the aimed paint.

Description

[Detailed description of the invention] Industrial applications The present invention relates to cationic electrodeposition coating compositions.

Conventional technologies and their problems Conventionally, the main types of curing reactions for cationic electrodeposition paint films include, for example, urethane curing reaction by isocyanate groups and active hydrogen groups, self-crosslinking curing by terminal activated double bonds, etc. It has been known. It is also widely recognized that lead compounds are effective as catalysts to promote these curing reactions.

Specific examples of lead compounds that have been blended into cationic electrodeposition paints and their blending methods include: ■Basic lead silicate;
Water-insoluble inorganic acid lead compounds such as basic lead sulfate, lead phosphate, and lead chromate are dispersed in advance with a pigment dispersion resin and then incorporated into the electrodeposition paint: ■ Dissolving water-soluble lead such as lead acetate in water. and then add it to the electrodeposition paint;
Examples include dispersing lead salts of oil-soluble long-chain fatty acids such as offtic lead and naphtic lead in water together with a dispersing resin for use in electrodeposition paints.

However, these methods have various deficiencies, and solutions to these problems are strongly desired. In other words, with the method (2) above, it is difficult to disperse the lead compound into fine particles, and because the lead compound has a high specific gravity, it tends to settle in the electrocoating paint, and the lead compound is likely to be sprinkled on the horizontal surface of the object to be coated, causing lumps. Therefore, we have no choice but to reduce the amount of lead compounds used. Moreover, since it is a granular solid substance, the frequency of contact (surface area) with the resin in the electrodeposition paint during baking is small, and most of them have a weak catalytic effect. In method (■) above, water-soluble lead takes the form of a salt with an acid, so like many low-molecular electrolytes, it promotes the electrolysis of water during the formation of an electrodeposited film, increasing the breakdown voltage of the film. This reduces the gas flow rate and tends to leave a large number of gas holes in the wet film. This causes serious defects such as poor smoothness after baking and gas holes, so the amount of the lead compound used is limited.

In addition, in the method (2) above, since the lead compound has a high long-chain fatty acid content, if a large amount of this compound is used, it will have a negative effect on corrosion resistance and significantly reduce water dispersibility, so the amount used is still limited. Ru.

Furthermore, in addition to the above-mentioned methods 1 to 2, a method using a chelation reaction product of a compound having a β-hydroxyamino structure and lead (II) oxide has recently been disclosed (JP-A-6
3-152676).

However, in this method, in order to increase the lead content, it is necessary to increase the concentration of alkanolamine reacted with lead oxide, and as a result, it is necessary to use a compound with a low molecular weight β-hydroxyamino structure. Gone, the above ■
The low molecular weight electrolyte, which is essentially the same defect as when water-soluble lead is used in method (2), causes a decrease in coating breakdown voltage, and similarly to the oil-soluble lead in method (2), a decrease in corrosion resistance is caused.

Means for Solving the Problems The present inventors have developed a cationic electrodeposition paint that eliminates all of the deficiencies in the conventional methods ① to ① above and can quickly and easily cross-link and cure the coating film. As a result of conducting research to achieve this goal, we have now discovered that the above objectives can be achieved by using lead maleate as a lead compound, and have completed the present invention.

Thus, according to the present invention, a cationic electrodeposition paint characterized by containing lead maleate is provided.

A feature of the present invention is that lead maleate is contained in the cationic electrodeposition paint. As a result, when the electrodeposition paint of the present invention is used, it has become possible to use the excellent catalytic effect of lead maleate, that is, to quickly crosslink and cure the cationic electrodeposition coating film.

Lead maleate can be easily dispersed in the form of fine particles in the electrodeposition paint. Furthermore, by containing lead maleate, it does not reduce the breakdown voltage of the coating film during electrodeposition coating, does not impair the smoothness of the coating film, and does not cause smearing.
It has been possible to achieve numerous advantages such as no deterioration in storage stability.

The above-mentioned high catalytic ability and easy dispersibility are thought to be due to the fact that lead maleate is an organic lead acid and is a chelate, and because it is water-insoluble, the coating film has excellent smoothness and stability. It is estimated that

Lead maleate used in the present invention can take several forms, but those represented by the following formula are particularly preferred, and those commercially available as reagents and industrial chemicals can be used. These are preferably granular or powdery solids at room temperature.

In the present invention, the cationic electrodeposition coating material for containing lead maleate is not particularly limited, and those known in the art can be used. Specifically, based on the type of crosslinking and curing reaction of the coating film, examples are those that utilize a urethane exchange reaction between a base resin having an amino group or a hydroxyl group and a blocked polyisocyanate compound (curing agent); Alternatively, one that utilizes a self-crosslinking reaction due to a polymerizable double bond in a side chain; etc. Furthermore, in addition to these, it can also be applied to cationic electrodeposition paints using an ethylene carbonate curing method or an ester amide exchange method.

As a result of detailed research by the present inventors on the catalytic curing effect of lead maleate in the cross-linking curing reaction of the electrodeposited film of cationic electrodeposition paints, lead maleate was incorporated into the cationic electrodeposition paints as exemplified above. By doing so, the various defects described above are not only eliminated, but also the present inventors have previously proposed a base resin having a primary hydroxyl group and a cationic group, and a curing resin containing an epoxy group as the main components. When applied to cationic electrodeposition paints (hereinafter sometimes abbreviated as "epoxy cured CHD paints") (see Japanese Patent Application No. 63-213660 and Japanese Patent Application No. 63-323591), further superior technical effects can be obtained. It turns out that you can get .

The base resin having primary hydroxyl groups and cationic groups used in this epoxy-cured CHD coating contains primary hydroxyl groups capable of reacting with epoxy groups and sufficient amount to form a stable aqueous dispersion. Any resin having a number of cationic groups is included. Examples of the base resin include the following.

(i) A reaction product obtained by reacting a polyepoxide compound and a cationizing agent; (i) A polycondensate of a polycarboxylic acid and a polyamine (see U.S. Pat. No. 2,450,940) with an acid. Protonated products: (ij) Polyadducts of polyisocyanates and polyols with mono- or polyamines, which are protonated with acids: (iv) Copolymers of acrylic or vinyl monomers containing hydroxyl groups and amino groups, which are protonated with acids. Protonated (Japanese Patent Publication No. 12395/1988, Japanese Patent Publication No. 12395/1983)
(V) Adduct of polycarboxylic acid resin and alkylene imine protonated with acid (US Patent No. 3,40)
3,088); etc.

For specific examples and manufacturing methods of these base resins, see, for example, Japanese Patent Publications No. 45-12395 and Japanese Patent Publication No. 45-12.
No. 396, Japanese Patent Publication No. 49-23087, U.S. Patent No. 2.450.940, U.S. Patent No. 3,40
3.088 specification, U.S. Patent No. 3.891,529, U.S. Patent No. 3.963.663, etc., so the detailed description will be referred to here. replace it with

Particularly desirable as the base resin are those obtained by reacting a cationizing agent with the epoxy groups of the polyepoxide compound of (1) above, which is obtained from a polyphenol compound and epichlorohydrin, because of its excellent anticorrosion properties. It is a reaction product.

The polyepoxide compound is an epoxy group compound and generally has a molecular weight of at least 200. Preferably 400 to 4,000,
More preferably, those having a number average molecular weight within the range of 800 to 2,000 are suitable. As such polyepoxide compounds, those known per se can be used, and include, for example, polyglycidyl ethers of polyphenols that can be produced by reacting a polyphenol compound with epichlorohydrin in the presence of an alkali. Examples of polyphenol compounds that can be used here include bis(4-hydroxyphenyl)-2,2-propane, 4,4' dihydroxybenzophenone, bis(4-hydroxyphenyl)-1,1-ethane, bis-(4-hydroxyphenyl)-1,1-ethane, and bis(4-hydroxyphenyl)-1,1-ethane. -hydroxyphenyl)-1,1-isobutane, bis(4-hydroxy-tert-butyl-
phenyl)-2,2-propane, bis(2-hydroxynaphthyl)methane, l,5-dihydroxynaphthalene,
Bis(2,4-dihydroxyphenyl)methane, tetra(4-hydroxyphenyl)-1,1,2゜2-ethane, 4.4'-dihydroxydiphenyl ether, 4.4
'-dihydroxydiphenylsulfone, phenol novolac, talesol novolac, etc. are mentioned.

Among the polyepoxide compounds described above, those particularly suitable for producing the base resin have a number average molecular weight of at least about 380.
, preferably about 800-2,000, and an epoxy equivalent weight in the range of 190-2,000, preferably 400-1,000;
In particular, it is a bisphenol A type epoxy resin represented by the following formula (%). The polyepoxide compound may be partially reacted with a polyol, polyether polyol, polyester polyol, polyamide amine, polycarboxylic acid, polyisocyanate, etc., and may also be graft-polymerized with δ-4 caprolactone, acrylic monomer, etc. .

On the other hand, examples of the cationizing agent reacted with the polyepoxide compound include aliphatic, alicyclic, or aromatic-aliphatic primary or secondary amines, tertiary amine salts, secondary sulfide salts, and tertiary phosphine salts. Examples include salt. These react with epoxy groups to form cationic groups.

Furthermore, a tertiary amino monoisocyanate obtained by the reaction of a tertiary amino alcohol and a diisocyanate can be reacted with a hydroxyl group of an epoxy resin to form a cationic group.

Examples of the amino compound in the cationizing agent include:
For example, the following can be exemplified.

(1) Methylamine, ethylamine, n- or 1s
o-7'lopylamine, monoethanolamine, n-
Also, primary amines (2) such as 1so-propanolamine, diethylamine, jetanolamine, di-n-
or secondary amines such as 1so-propertoolamine, N-methylethanolamine, and N-ethylethanolamine.

(3) Polyamines such as ethylene diamine, diethylene triamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, dimethylaminoethylamine minopropylamine.

Among these, alkanolamines having a hydroxyl group are preferred. The primary amine 7 group may be blocked by reacting with a ketone in advance, and then the remaining active hydrogen may be reacted with an epoxy group.

Furthermore, in addition to the above-mentioned amine compounds, basic compounds such as ammonia, hydroxylamine, hydrazine, hydroxyethylhydrazine, and N-hydroxyethylimidacillin compounds can also be used. The basic groups formed using these compounds are acids, particularly preferably formic acid, acetic acid,
It can be protonated with a water-soluble organic carboxylic acid such as lactic acid to form a cationic group.

Furthermore, triethylamine, triethanolamine, N
, N-dimethylethanolamine, N-methyljetanolamine, N,N'-diethylethanolamine, N
Tertiary amines such as -ethyljetanolamine can also be used, which can be preprotonated with acid and reacted with epoxy groups to form quaternary salts.

In addition to amino compounds, salts of sulfides such as diethyl sulfide, diphenyl sulfide, tetramethylene sulfite, and thiogetanol with boric acid, carbonic acid, organic monocarboxylic acids, etc. can be reacted with epoxy groups to form a tertiary compound.
It may also be used as a class sulfonium salt.

Furthermore, a salt of a phosphine such as triethylphosphine, phenyldimethylphosphine, diphenylmethylphosphine, or triethylphosphine and the above-mentioned acid may be reacted with an epoxy group to form a quaternary phosphonium salt.

The content of primary hydroxyl groups in the base resin is generally about 1 in terms of hydroxyl value from the viewpoint of reactivity with the epoxy groups in the cured resin described later.
A range of 0 to 400, particularly 20 to 200, is preferred. The content of the cationic group is preferably as small as possible to stably disperse the base resin in water, and is generally in the range of 3 to 100, particularly 8 to 80 in terms of KOH (mg/g solid content). preferable. However, even if the content of cationic groups is 3 or less, it is possible to use aqueous dispersion using a surfactant, but in this case, the pH of the aqueous dispersion is It is desirable to adjust the cationic group to 4-9, preferably 6-7.

The base resin used in the epoxy cured CHD paint has a primary hydroxyl group and a cationic group, and as a general rule, it is desirable that it does not contain free epoxy groups.

Next, as the epoxy group-containing curing resin used in combination with the above-mentioned base resin, for example, an epoxy resin containing 2 to 30 repeating units represented by the following formula () (hereinafter referred to as "curing resin (A )" and the following formula (II) CH.

A polymer with a number average molecular weight of 200.000 or less (hereinafter abbreviated as "curing resin (B)") having a repeating unit represented by C 繻O (ff), where R is a hydrogen atom or a methyl group. ) can be given.

More specifically, first of all, as the curing resin (A), for example, JP-A No. 60-170620, JP-A No. 32
The above-mentioned curing resin (A) is as follows. As shown in formula (I[I), it can have a polymerization initiating component residue X at the terminal.

In the formula, n is an integer of 2 to 30. Here, X is an organic residue having active hydrogen, and examples of the organic substance having active hydrogen, which is a precursor thereof, include EVA, alcohols, phenols, Examples include carboxylic acids, amines, thiols, and the like.

Alcohols may be monohydric alcohols or polyhydric alcohols of dihydric or higher hydrity, specifically methanol, ethanol, propatool,
Aliphatic monohydric alcohols such as butanol, pentanol, hexanol, octatool; Aromatic monohydric alcohols such as benzyl alcohol: ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, phlopylene gelicol, cyfropylene glycol, 1 .3-butanediol, 1,4-butanediol, bentanediol, l,6-hexanediol, neopentyl glycol, oxypivalic acid neopentyl glycol ester cyclohexane dimetatool, glycerin, diglycerin, polyglycerin, trimethylolpropane , trimethylolethane, pentaerythritol, and polyhydric alcohols such as pentaerythritol.

Examples of phenols include phenol, cresol, catechol, progallol, hydroquinone, hydroquinone 7-methyl ether, and bisphenol A1.
Examples include bisphenol F, 4.4' dihydroxybenzophenone, bisphenol s1 phenol resin, and cresol novolak resin.

Carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, fatty acids from animal and vegetable oils; 7-malic acid, maleic acid, adipic acid, dodecanoic acid, trimellitic acid, pyromellitic acid,
Examples include polyacrylic acid, 7-thalic acid, isophthalic acid, and terephthalic acid, and compounds having both a hydroxyl group and a carboxylic acid such as lactic acid, citric acid, and oxycaproic acid can also be used.

In addition, as compounds having active hydrogen, polyvinyl alcohol, polyvinyl acetate partial hydrolyzate, starch, cellulose, cellulose acetate, cellulose acetate butyrate, hydroxyethyl cellulose,
Allyl polyol resin, styrene-allyl alcohol copolymer resin, styrene-maleic acid copolymer resin, alkyd resin, polyester polyol resin, polycaprolactone polyol resin, etc. can also be used. Also,
The compound having active hydrogen may have an unsaturated double bond in its skeleton together with active hydrogen, and may also have a structure in which the unsaturated double bond is epoxidized.

In the formula (I), n, which represents the number of repeating units, is 2.
-30, but when n exceeds 30, the resin generally has a high melting point and is difficult to handle.

Specifically, the curing resin (A) is usually a polyether resin obtained by ring-opening polymerization of 4-vinylcyclohexene-l-oxide using the above-mentioned active hydrogen-containing organic compound as an initiator, that is, vinyl It can be produced by epoxidizing a ring-opened polycyclohexene oxide polymer having a group side chain with an oxidizing agent such as a peracid.

4-vinylcyclohexene-1-oxide is, for example,
It can be obtained by partially epoxidizing vinylcyclohexene obtained by a dimerization reaction of butadiene with peracetic acid. 4-hinyl chlorohexene
- When carrying out ring-opening polymerization of oxide in the presence of active hydrogen, it is generally preferable to use a catalyst, and examples of catalysts that can be used include amines such as methylamine, ethylamine, propylamine, and piperazine, and pyridines;
Organic basic acids such as imidazoles; Organic acids such as formic acid, acetic acid, and propionic acid; Inorganic acids such as sulfuric acid and hydrochloric acid; Alkali metal alcoholades such as sodium methylate; KOH,
Alkali such as NaOH; BF3ZnCQ2, AQCQ
s, SnCQ. Lewis acids such as or complexes thereof, and organometallic compounds such as triethylaluminum and diethylzinc.

These catalysts contain 0.001 to 10% by weight of the reactants.
, preferably in a range of 0.1 to 5% by weight. The ring-opening polymerization reaction temperature is generally -70 to 200°C,
Preferably the temperature is -30°C to 100°C. The reaction can be carried out using a solvent, and it is preferable to use a conventional solvent that does not contain active hydrogen. In some cases, in addition to 4-vinylcyclohexene oxide, σ
- Monoepoxides such as epoxides of olefins may be copolymerized.

By epoxidizing the vinyl group side chain of the polycyclohexene oxide ring-opened polymer having a vinyl group side chain to be synthesized in this way, a curing resin (A) of formula (I) is obtained, and the epoxy The conversion can be carried out using peracids, hydroperoxides, and the like. As peracids, for example, performic acid, peracetic acid, perbenzoic acid, trifluoroperacetic acid, etc. can be used, and as hydroperoxides, for example, hydrogen peroxide, tart-butyl peroxide, cumene peroxide, etc. can be used. etc. can be used. The epoxidation reaction can be carried out using a catalyst if necessary. Whether or not a solvent is used during the epoxidation reaction and the reaction temperature can be adjusted as appropriate depending on the equipment used and the physical properties of the raw materials. Depending on the conditions of the epoxidation reaction, the substituent represented by the following formula (TV) in the raw material and/or the substituent represented by the following formula (V) that comes from the raw material at the same time as the epoxidation of the vinyl group in the raw material polymer. As a result of a side reaction with an epoxidizing agent or the like, modified substituents may be generated and may be included in the curing resin (A).

The proportion of these modified substituents is determined by the type of epoxidizing agent, the molar ratio of the epoxidizing agent to the vinyl group, and the reaction conditions.

Commercially available products can also be used as the curing resin (A), such as EHPE3150 (trade name, manufactured by Daicel Chemical Industries, Ltd.).

Next, as the curing resin (B), a polymer having a number average molecular weight of 2oo, ooo or less and having a repeating unit represented by the following formula % formula % where R is a hydrogen atom or a methyl group is used. Ru.

The curing resin (B) is usually represented by the following formula (Vl), R
is hydrogen or a methyl group, or it can be produced by polymerizing at least one of these monomers with another polymerizable monomer. The above formula (V
For example, the seven points shown in l) are 3
．． 4-Epoxycyclohexylmethyl acrylate, 3
．． Examples include 4-epoxycyclohexylmethyl acrylate.

As these commercially available products, for example, M manufactured by Daicel Chemical Industries, Ltd.
Examples include ETHB and AETHB (both product names).

In addition, other polymerizable monomers that can be copolymerized with the hexamer represented by the above formula (Vl) can be selected from a wide range depending on the desired performance, and representative examples are as follows. be.

(a) Esters of acrylic acid or methacrylic acid; for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, methacrylate C1-18 alkyl esters of acrylic acid or methacrylic acid such as ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate; methoxybutyl acrylate, methacrylic acid C2-18 alkoxyalkyl esters of acrylic acid or methacrylic acid such as methoxybutyl, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, and ethoxybutyl methacrylate; acrylic acid such as allyl acrylate and allyl methacrylate; C2-8 alkenyl ester of methacrylic acid; C2-8 hydroxyalkyl of acrylic acid or methacrylic acid such as hydroxyloethyl acrylate, human kilodiethyl methacrylate, human kilodipropyl acrylate, human kilodipropyl methacrylate Ester: C3-18 alkenyloxyalkyl ester of acrylic acid or methacrylic acid such as allyloxyethyl acrylate and allyloxymethacrylate.

(b) Vinyl aromatic compounds: for example, styrene, α
-Methylstyrene, vinyltoluene, p-chlorostyrene.

(c) Polyolefin compound: For example, butadiene,
Isoprene, chloroprene.

(d) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone, vinyl acetate beoba monomer (Shell Chemicals), hinylgropionate,
Vinyl pivalate, a vinyl compound having a polycaprolactone chain (for example, FM-3X monomer: trade name manufactured by Daicel Chemical Industries, Ltd.), and the like.

In the curing resin (B), the amount of monomers represented by the formula (Vl) used is such that at least two monomers are contained in one molecule of the resin (B), and the amount of monomers represented by the formula (Vl) is determined based on the crosslinking density of the cured coating film. Based on the curing speed and the like, it is preferable that the solid content of the curing resin (B) be at least 50% by weight.

The above-mentioned curing resin (B) can be produced by the same method and under the same conditions as those for general synthesis reactions of acrylic resins, vinyl resins, and the like. An example of such a synthesis reaction is a method in which each monomer component is dissolved or dispersed in an organic solvent, and heated with stirring at a temperature of about 60 to 180°C in the presence of a radical polymerization initiator. can. The reaction time can generally be about 1 to 10 hours. Further, as the organic solvent, alcohol solvents, ether solvents, ester solvents, hydrocarbon solvents, etc. can be used.

When using a hydrocarbon solvent, it is preferable to use other solvents in view of solubility. Further, as the radical initiator, any commonly used radical initiator can be used, and specific examples thereof include benzoyl peroxide, 7-
Peroxides such as butylperoxy-2-ethylhexanoate; azo compounds such as azoinbutylnitrile and asohisdimethylvaleronitrile; and the like.

The curing resin (B) has a number average molecular weight of 3,000 to 2.
About 00.000 is preferable, especially 4.000 to
A value of about 10,000 is more preferable.

In the epoxy cured CED paint, the composition ratio of the above base resin and the curing resin (A) and/or (B) depends on the type of base resin used and is necessary for the resulting coating film to be thermally cured. Although the amount can be changed as appropriate within the range of the minimum amount to the maximum amount that does not impair the stability of the cationic electrodeposition paint, generally the weight ratio of the solid content of the curing resin to the base resin is 0.2 to 1.5. It is preferable to select it so that it falls within the range of . Further, a part of the curing resin may include a resin added in advance to the base resin.

A composition containing the above-mentioned base resin and curing resin (A) and/or (B) as main components can be used as a cationic electrodeposition paint containing lead maleate in the present invention.

In the present invention, the method of blending lead maleate into the cationic electrodeposition paint is not particularly limited, and powdered or granular forms may be blended as they are. For example, lead maleate alone or together with other pigments can be dispersed in a ball mill using a pigment dispersion resin, and then incorporated into a cationic electrodeposition paint.

The amount of maleic acid added to the cationic electrodeposition paint can be arbitrarily selected depending on the purpose, but in general, it is 0.05 to 15% by weight as metallic lead, preferably 0.5% by weight, based on the solid content of the former resin. It is preferable to adjust the lead content to 10% by weight.

Furthermore, the cationic electrodeposition paint of the present invention may optionally contain color pigments such as carbon black, titanium white, lead white, and red iron; extender pigments such as clay and talc; strontium dichromate, lead chromate, and litharge. , anticorrosive pigments such as red lead, basic lead silicate, lead phosphate, basic lead sulfate, and lead silicate; or other additives may be further kneaded.

Other additives that may be blended include, for example, small amounts of nonionic surfactants and curing accelerators as dispersants or anti-repellents on coated surfaces.

The cationic electrodeposition paint of the present invention can be cationically electrodeposited by a normal method, and the electrodeposition coating film is, for example, 80%
~250'C! , preferably at a temperature in the range of 120 to 160°C.

Next, the present invention will be explained in more detail with reference to Examples. In the Examples, all "parts" are "parts by weight" and "%" are "% by weight".

Example 1 39 parts of monoethanolamine were kept at 60°C in a reaction vessel, and 1 part of N,N-dimethylaminopropylacrylamine was added.
100 parts was added dropwise, reacted at 60'O for 5 hours, and N,N
- A monoethanolamine adduct of dimethylaminopropylacrylamide was obtained.

Separately, 950 parts of bisphenol A diglycidyl ether with an epoxy equivalent of 190, and epoxy resin XB-4122 (manufactured by Ciba Geigy, trade name) with an epoxy equivalent of about 330, about 3
30 parts of bisphenol A, 456 parts of bisphenol A, and 21 parts of jetanolamine were charged, the temperature was raised to 120°C, and the epoxy value was 1.02 mi! After reacting to 1 g of J mole, dilute with 476 parts of ethylene glycol monobutyl ether,
After cooling, while maintaining the temperature at 100°C, 158 parts of jetanolamine and 43 parts of the monoethanolamine adduct of the above N,N-dimethylaminopropylacrylamide were added, and the reaction was carried out until the viscosity stopped increasing, and the resin solid content was reduced. An 80% base resin solution (2) was obtained.

On the other hand, EHPE3150 [epoxy equivalent 175-19
5. Epoxy resin manufactured by Daicel Chemical Industries, Ltd.] 32.6
and 8.2 parts of propylene glycol monomethyl ether were heated and dissolved at 100°C to obtain 40.8 parts of a curing resin solution (A-1) having a solid content of 80% and an epoxy equivalent of 190. Mix this with 84.2 parts of the above base resin solution (■) and 11 parts of a 10% formic acid aqueous solution, and while stirring, add 36 parts of deionized water.
4 parts to obtain 500 parts of a cationic electrodeposition paint with a solids content of 20%.

Next, 14.7 parts of the above base resin solution (1) and 2.5 parts of a 10% formic acid aqueous solution were mixed, 25 parts of deionized water was added while stirring, and lead maleate (Kanto Kagaku Co., Ltd. reagent) was mixed. Lead maleate paste 5 with a solid content of 40% and a metallic lead content of 8% was prepared by blending 7.8 parts of grade 1) and dispersing it in a ball mill for 24 hours.
Get 0 copies. Fifty parts of this paste, 500 parts of the above 20% cationic electrodeposition paint, and 37.5 parts of deionized ice are mixed to obtain a cationic electrodeposition bath of pt-i5.4. The content of metallic lead is about 3.6% based on the resin solid content.

Example 2 Bisphenol A type epoxy resin with an epoxy equivalent of 950 [trade name "Epicote 1004," manufactured by Shell Chemical Co., Ltd.
1,900 parts of butyl cellosolve was dissolved in 993 parts of butyl cellosolve, and 21 parts of jetanolamine (cationizing agent) was dissolved in 8 parts of
After dropwise addition at 0 to 100°C, the mixture was kept at 100°C for 2 hours to obtain an epoxy resin-amine adduct (base resin solution ■) having a solid content of 68% and an amine value of 53. This base resin solution ■1
00 parts by adding 3.2 parts of 88% formic acid to neutralize. It has a primary hydroxyl value of 106, a cationic group of 53 KOH (mg/g solid content), and contains almost no free epoxy groups.

A solution of 2 parts of azobisdimethylvaleronitrile in 33.4 parts of METHB (3,4-epoxycyclohexylmethyl methacrylate-1-) was heated to loo'c to add 71,710 parts of methyl inbutyl and 11 parts of butyl serotonin.
It was added dropwise over 2 hours to a mixed solvent with 0 parts of
%, epoxy equivalent: 196 curing resin solution (B-1) 5
Get 4 copies.

343 parts of deionized water and 54 parts of the curing resin solution (B-1) were added to 103 parts of the formic acid neutralized product of the base resin solution (1) to obtain a 20% cationic electrodeposition paint.

500 parts of this electrodeposition paint is mixed with 60 parts of the lead maleate paste in Example 1 and 40 parts of deionized water to obtain a cationic electrodeposition bath with a pH of 5.4.The content as metallic lead is It is 4.2% based on the resin solid content.

Example 3 80% curing resin solution (A-1) in Example 1 40
．． 8 parts of the 60% curing resin solution (B-1) of Example 2
It was replaced with 4th part.

Example 4 174 parts of methyl ethyl ketoxime was added dropwise to 222 parts of isophorone diisocyanate at 50°C, and after 3 hours it was diluted with 264 parts of propylene glycol monomethyl ether to form a blocked isocyanate with a solid content of 60%, which was used as a curing resin. This will be referred to as solution (C-1).

Mix 100 parts of the base resin solution (1) of Example 1, 34 parts of the above curing resin solution (C-1), and 1.8 parts of formic acid, and dilute with 364 parts of deionized water to prepare a 20% emulsion. .

400 parts of this emulsion, 71 parts of the haste of Example 1, and 124 parts of deionized water are mixed to obtain a cationic electrodeposition bath having a pH of 6.1. The content of metallic lead was 5.8% based on the resin solid content.

Comparative Examples 1 to 2 In Example I, instead of lead maleate, lead acetate (Comparative Example 1) and secanoic lead (Comparative Example 2) were each mixed as metallic lead in the same amounts as in Example 1 to create a cationic electrodeposition bath. get.

Comparative Example 3 In Example 3, a cationic electrodeposition bath is obtained by adding basic lead silicate as metallic lead in place of lead maleate in the same amount as in Example 4. Comparative Example 4 Bisphenol A diglycidyl with an epoxy equivalent of 190 Jetanolamine 2 was added to 380 parts of ether at 60°C in the presence of 512 parts of propylene glycol monomethyl ether.
10 parts are allowed to react for 4 hours.

The temperature was raised to 120°C, 223 parts of lead oxide was added little by little, and the mixture was allowed to react for 6 hours. An additional 20 parts of acetic acid is added and diluted with 3955 parts of deionized water to create a 15% chelated lead aqueous dispersion containing 3.9% lead metal.

This chelate lead aqueous dispersion was replaced with maleic lead paste t in Example 3, and the content as metallic lead was changed to Example 3.
Mix to make the same amount.

Comparative Example 5 In Example 4, a cationic electrodeposition bath is obtained by adding Octyx lead as a metal lead in the same amount as in Example 4 instead of lead maleate.

[Performance Test and Results 1 The cationic electrodeposition paints obtained in Examples 1 to 4 and Comparative Examples 1 to 5 and their coating film performance were investigated by the following method.

Test method (1) Film breakdown voltage: Cationic electrodeposition paint is electrodeposited on a zinc phosphate-treated board at 30°C, and the voltage (V) at which the coating becomes unpaintable due to coating breakdown is determined as the coating film breakdown voltage (V). shall be.

(2) Curability of coating film: The coating film baked at +50°C for 30 minutes was cured at 60°C in a mixed solvent of acetone and methanol (l/l by weight).
The weight loss before and after dipping is divided by the weight of the coating film before dipping, and the resulting value is taken as the gel fraction of the cured coating film. △, 90%
Less than is marked as ×.

(3) Smoothness: Based on visual evaluation, a good coating film is marked as ○, whereas a coating film whose smoothness is impaired due to "fine wrinkle-like irregularities" or the like is marked as poor.

(4) Impact resistance (Dupont method): After placing the test plate in a constant temperature and humidity environment for 24 hours at a temperature of 20:I:0% and humidity of 75±2%, a test plate of the specified size was placed in a DuPont impact tester. Attach the stand and the impact center, place the test plate between them with the painted surface facing upward, and then drop a specified weight onto the impact center from the specified height. No cracking or peeling of the paint film due to impact is observed. The time is ○, the one that is slightly noticeable is △, and the one that is noticeable is X.

(5) Spray resistance: Tested in accordance with JIS Z2871, and the creep from the cut (not linearly cut) portion was measured on the side 2. It is considered to be passed when the 7 sag of the coating film other than the cut part is within 0 mm and 8F (ASTM) or less. Passing the test is marked with ○, and failing is marked with ×.

result The results are summarized in the table below.

Claims (5)

[Claims] (1) A cationic electrodeposition paint characterized by containing lead maleate. (2) The cationic electrodeposition paint according to claim (1), which contains as main components a base resin having a primary hydroxyl group and a cationic group and an epoxy curing agent. (3) The cationic electrodeposition paint according to claim (2), wherein the curing agent is an epoxy resin containing 2 to 30 repeating units represented by the following formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I). (4) The curing agent has the following formula ▲ Numerical formula, chemical formula, table, etc. ▼ (II) In the formula, R is a hydrogen atom or a methyl group, and has a number average molecular weight of 3.0
The cationic electrodeposition paint according to claim 2, which is a polymer having a molecular weight of 00 to 200,000. (5) The cationic electrodeposition paint according to claim (1), characterized in that lead maleate is contained as metallic lead in an amount of 0.5 to 10% by weight based on the resin solid content.