JPH0711178A - Cationic electrodeposition coating material and method for electrodepositing the same - Google Patents

Abstract

PURPOSE:To obtain the subject material which can form a coating film excellent in especially smoothness, edge corrosion prevention, etc., and to provide the subject method. CONSTITUTION:This coating material mainly consists of a base resin (A) having hydroxyl groups and cationic groups and prepared by reacting an epoxy resin with a sec. alkanolamine, a pigment dispersion (B) prepared by dispersing a pigment (B-2) in a cationic resin (B-1) prepared by reacting an epoxy resin (a) having at least two epoxy functional groups of the formula (wherein (n) is an integer of 2-4) in the molecule with bath of an amino compound (b) having a hydroxyl group, a sec. amino group and an amide group in the molecule and an amino compound (c) having a prim. hydroxyl group and a prim or sec. amino group and having an electrodeposition rate adjusted to be higher than that of component A, and a curing agent (C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cationic electrodeposition coating and its coating method, and more particularly to a cationic electrodeposition coating which forms a coating film excellent in smoothness and edge corrosion resistance and its coating method.

[0002]

2. Description of the Related Art Electrodeposition coating has excellent throwing power and film thickness uniformity and is widely used for undercoating of automobile bodies. However, the electrodeposition coating film has insufficient smoothness because gas is generated during its deposition and the deposition coating film has a high solid content. This smoothness is improved by lowering the melt viscosity of the coating film when it is cured by heating. On the other hand, the smoothness at the edge of the cut surface of the article to be coated, the corners of the bent portion and the protrusions is also improved. The film forming property is deteriorated, and the corrosion resistance of the edge portion (so-called edge covering property) is deteriorated, which causes a defect.

[0003]

Therefore, the present applicant has conducted research on an electrodeposition coating method which is excellent in both edge covering properties and coating surface smoothness, and has been studied for a plurality of electrodes having different electrodeposition deposition rates and heating melt flowability. We have found that the above object can be achieved by using a cationic resin together and have already proposed it (JP-A-4-91170).

The inventors of the present invention have studied this proposal in more detail. As for the edge covering property of the formed coating film, the performance test result in a short period is good, but the performance test time is long. Then, it turned out that it had a defect that it was not practically sufficient. That is, the corrosion resistance of the edge portion is not sufficiently improved.

The present invention relates to a novel cationic electrodeposition coating composition which can form a coating film having a good edge covering property and coating surface smoothness over a long period of time, and a coating method therefor.

That is, the present invention is as follows: (A) a base resin having a hydroxyl group and a cationic group, which is obtained by reacting an epoxy group-containing resin with a secondary alkanolamine, and (B) the following formula (1) in one molecule:

[0007]

[Chemical 2]

(In the formula, m is an integer of 2 to 4.)

An epoxy resin (a) having at least two functional groups containing an epoxy group represented by is added to an amino compound (b) having a hydroxyl group, a secondary amino group and an amide group in one molecule and a second compound in one molecule. A cationic resin prepared by reacting an amino compound (c) having a primary hydroxyl group and a primary or secondary amino group, and adjusting the electrodeposition deposition rate to be higher than that of the component (A). (B-
1. A pigment dispersion liquid in which the pigment (B-2) is dispersed by using 1), and a cationic electrodeposition coating composition containing (C) a curing agent as a main component. The above-mentioned cationic electrodeposition coating composition is a main component of the electrodeposition bath is immersed in a conductive coating object as a cathode, and an electric current is applied between the anode and the
In the initial stage, the component (B) is precipitated, and then (A)
The present invention relates to a cationic electrodeposition coating method, which is characterized in that components are deposited.

In the present invention, the electrodeposition deposition rate indicates the degree of slowness of the deposition (migration) of the cationic resin on the article to be coated in the cationic electrodeposition coating. The specific measuring method is as follows.

First, the solid content concentration of the aqueous dispersion or aqueous solution of the above-mentioned components (A) and (B-1) is adjusted to 15% by weight and the temperature is adjusted to 28 ° C., and the zinc phosphate-treated steel sheet is immersed in this. , Constant current density (specifically, 0.25mA / cm ² ~
It shows that the electrodeposition coating film was formed at the time when the voltage between electrodes rapidly increased while energizing at 0.75 mA / cm ² ), and the time from the start of this current supply until the voltage between electrodes rapidly increased (usually about 5 (Within minutes) is measured, and this is defined as the electrodeposition deposition rate. The shorter this time, the faster the electrodeposition rate.

In the present invention, the above (A) and (B-
The electrodeposition deposition rate of component 1) is measured within the above current density range, and it is preferable to compare both components based on the results measured under the same conditions.

In the present invention, the component (B-1) is more preferable than the component (A).
The components have a faster electrodeposition deposition rate, that is, it is necessary that the time from the start of energization to the sharp increase in the inter-electrode voltage is short. More specifically, for example, the current density is 0.5 mA / c
In m ² , the electrodeposition deposition rate of the component (A) is 120 to 30.
0 second, that of the component (B-1) is preferably 50 to 120 seconds, the difference between the two components is 50 seconds or more, and particularly 60 to 1
It is preferably 50 seconds.

The components (A), (B) and (C) used in the present invention will be specifically described.

Component (A): A base resin having a hydroxyl group and a cationic group, which is obtained by reacting an epoxy group-containing resin with a secondary alkanolamine, and has an electrodeposition deposition rate slower than that of the following component (B-1).

The component (A) has a hydroxyl group capable of undergoing a cross-linking reaction with the component (C) described later, and a cationic group sufficient to form a stable aqueous dispersion or aqueous solution. It is obtained by reacting a group-containing resin with a secondary alkanolamine.

The epoxy group-containing resin is an epoxy group

[Chemical 3] Having a number average molecular weight in the range of at least 200, preferably 400 to 4,000, more preferably 800 to 2,000, and an epoxy equivalent of 190 to Those of 2,000, especially 400 to 1,000, are suitable. As such a polyepoxy resin, those known per se can be used, and examples thereof include polyglycidyl ethers of polyphenol compounds which can be produced by reacting a polyphenol compound with epichlorohydrin in the presence of an alkali. It Examples of the polyphenol compound 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-isobutane, bis (4-hydroxy-te
rt-Butyl-phenyl) -2,2-propane, bis (2
-Hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, bis (2,4-dihydroxyphenyl) methane, tetra (4-hydroxyphenyl) -1,1,
2,2-ethane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone,
Examples thereof include phenol novolac and cresol novolac.

Among them, the following formula

[0019]

[Chemical 4]

Those represented by are preferred.

The polyepoxy resin may be partially reacted with a polyol, a polyether polyol, a polyester polyol, a polyamidoamine, a polycarboxylic acid, a polyisocyanate or the like, and further, δ-4 caprolactone, an acrylic monomer or the like may be grafted. It may be polymerized.

The component (B-1) obtained by reacting the following components (a), (b) and (c) can also be applied as the component (A) by adjusting the electrodeposition deposition rate.

The secondary alkanolamine reacted with the epoxy resin is a compound having at least one hydroxyl group and at least one secondary amino group in one molecule, and the hydroxyl group is preferably a primary hydroxyl group. The amino group of the alkanolamine reacts with the epoxy group of the epoxy resin to introduce a tertiary amino group (cationic group) and a hydroxyl group (preferably a primary hydroxyl group) into the resin.

Examples of such secondary alkanolamines include N-methylethanolamine, N-ethylethanolamine, diethanolamine, di-n (or iso) -propanolamine, dibutanolamine, etc .: monoethanolamine, monopropanol Primary alkanolamines such as amines and monobutanolamines and α, β-unsaturation such as N, N-dimethylaminopropyl acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate Addition products with carbonyl compounds: etc.

Since these secondary alkanolamines may have different electrodeposition deposition rates depending on their components,
It is preferable to select and use with reference to the electrodeposition deposition rate of the following component (B-1) and the like.

The hydroxyl group and the cationic group of the component (A) are mainly introduced by the secondary alkanolamine, but the hydroxyl group introduced by a method other than this may be contained. Further, as the hydroxyl group, a primary hydroxyl group is preferable because it has excellent crosslinking reactivity with the curing agent (C).

The content of the hydroxyl group in the component (A) is preferably 20 to 5,000, more preferably 100 to 1,000, in terms of the hydroxyl group equivalent in view of the cross-linking reactivity with the curing agent (C). The primary hydroxyl group equivalent is preferably in the range of 200 to 1,000, and the content of the cationic group is preferably at least the necessary level at which the component (A) can be stably dispersed in water, and KOH (mg / g solid Min) (amine value) conversion is generally 3 to 200, and particularly preferably 10 to 100.

In principle, it is preferable that the component (A) does not have a free unreacted epoxy group.
It is also possible to protonate the tertiary amino group of the component (A) with an acidic compound and then disperse or dissolve it in water. The compound described below can be used as the acidic compound.

Component (B): The following formula (1) in one molecule:

[0030]

[Chemical 5]

(In the formula, m is an integer of 2 to 4.)

The epoxy resin (a) having at least two epoxy group-containing functional groups represented by is added to an amino compound (b) having a hydroxyl group, a secondary amino group and an amide group in one molecule and a second compound in one molecule. Cationic property obtained by reacting an amino compound (c) having a primary hydroxyl group and a primary or secondary amino group and adjusting the electrodeposition deposition rate to be higher than that of the component (A). Resin (B
-1) is used to disperse the pigment (B-2).

The cationic resin (B-1) component can be obtained by reacting the components (a), (b) and (c).

Component (a): An epoxy resin used in the preparation of the cationic resin (B-1) and having at least two epoxy group-containing functional groups represented by the following structural formula (1) in one molecule.

[0035]

[Chemical 6]

In the formula, m is an integer of 2 to 4, preferably 4.

The epoxy resin (a) may be one known per se, for example, JP-A-60-170.
620, JP-A-62-135467, JP-A-60-166675, and JP-A-60-16197.
Those described in Japanese Patent Laid-Open No. 3-265975 and Japanese Patent Laid-Open No. 2-265975 can be used. In particular, Japanese Patent Application Laid-Open No. 2-265975 of the present applicant discloses the composition of the epoxy resin,
The manufacturing method and the like are described in detail. Therefore, all the descriptions about the epoxy resin described in the publication can be applied to the epoxy resin as the component (B-1) as it is.

The above-mentioned component (a) also includes the one in which the residue of the polymerization initiation component, that is, the active hydrogen-containing organic compound residue is bonded to the terminal of the above structural formula (1). Examples of the active hydrogen-containing organic compound that is a precursor thereof include alcohols such as aliphatic monohydric alcohols, aromatic monohydric alcohols and divalent or higher aliphatic or alicyclic polyhydric alcohols; phenols, fatty acids, Aliphatic (or alicyclic or aromatic) dibasic acid or polybasic acid; oxyacid; polyvinyl alcohol, polyvinyl acetate partial hydrolyzate,
Starch, cellulose, cellulose acetate, cellulose acetate butyrate, hydroxyethyl cellulose, allyl polyol resin, styrene-allyl alcohol copolymer resin, alkyd resin, polyester polyol resin, polycaprolactone polyol resin; Further, the compound having active hydrogen may have a structure in which an unsaturated double bond is epoxidized in the skeleton together with active hydrogen.

The epoxy resin as the component (a) is prepared, for example, by using the active hydrogen-containing organic compound as an initiator,
Vinyl cyclohexene-1-oxide alone or in the presence of other epoxy group-containing compound, ring-opening (co) polymerization of the epoxy group contained in each, to form a polyether resin, then It can be produced by epoxidizing the vinyl group present in the side chain in the resin with an oxidizing agent such as peracids or hydroperoxides.

4-Vinylcyclohexene-1-oxide is obtained, for example, by partially epoxidizing vinylcyclohexene obtained by the dimerization reaction of butadiene with peracetic acid.

The other epoxy group-containing compound that can be copolymerized is not particularly limited as long as it is a compound having an epoxy group, but a compound having one epoxy group in one molecule is preferable in production. Specifically, ethylene oxide, propylene oxide, butylene oxide and the formula:

[0042]

[Chemical 7]

Α-olefin epoxide represented by [wherein n is an integer of 2 to 25]; an oxide of an unsaturated compound such as styrene oxide; allyl glycidyl ether, 2-ethylhexyl glycidyl ether, methyl glycidyl ether, Examples thereof include glycidyl ether of a compound having a hydroxyl group such as butyl glycidyl ether and phenyl glycidyl ether; glycidyl ester of organic acid such as fatty acid.

The other epoxy group-containing compound further includes an alicyclic oxirane group-containing vinyl monomer having an unsaturated bond, and specific examples thereof include the following.

[0045]

[Chemical 8]

[0046]

[Chemical 9]

In the above formulas, R ₁₁ represents a hydrogen atom or a methyl group, R ₁₂ represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and R ₁₃ represents 2 to 1 carbon atoms. Represents a valent hydrocarbon group.

In the above formula, the divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms represented by R ₄ is
Examples thereof include linear or branched alkylene groups such as methylene, ethylene, propylene, tetramethylene, ethylethylene, pentamethylene groups and the like. Examples of the divalent hydrocarbon group having 1 to 10 carbon atoms represented by R ₅ include methylene, ethylene, propylene, tetramethylene, ethylethylene, pentamethylene, hexamethylene, polymethylene, phenylene,

[0049]

[Chemical 10]

Examples thereof include a group.

Further, the following general formula

[0052]

[Chemical 11]

In the formula, R ₁₁ and R ₁₂ have the same meanings as described above, and a compound represented by the following formula (eg, glycidyl acrylate, glycidyl methacrylate, etc.) and the following formula partially produced by partial epoxidation of vinylcyclohexene.

[0054]

[Chemical 12]

Compounds having an alicyclic unsaturated group such as those shown in can also be used as other epoxy group-containing compounds. Furthermore, 4-vinylcycloheptene (vinyl norbornene) or the like can also be used.

The ring-opening (co) polymerization reaction of an epoxy group, which is carried out in the presence of 4-vinylcyclohexene-1-oxide alone or in combination with another epoxy group-containing compound, uses a catalyst in the presence of an active hydrogen-containing organic compound. It is preferable to carry out. Examples of the catalyst include amines such as methylamine, ethylamine, propylamine and piperazine; organic bases such as pyridines and imidazoles; organic acids such as formic acid, acetic acid and propionic acid; inorganic acids such as sulfuric acid and hydrochloric acid. An alkali metal alcoholate such as sodium methylate; an alkali such as KOH or NaOH; a Lewis acid such as BF ₃ SnCl ₂ , AlCl ₃ , SnCl ₄ or a complex thereof; an organometallic compound such as triethylaluminum or diethylzinc; I can give you.

These catalysts usually have a pH of 0.
It can be used in the range of 001 to 10% by weight, preferably 0.1 to 5% by weight. The ring-opening (co) polymerization reaction temperature is generally -70 to 200 ° C, preferably -30 to 100.
Within the range of ° C. This reaction is preferably carried out using a solvent, and as the solvent, a usual organic solvent having no active hydrogen can be used.

By thus epoxidizing the vinyl group (—CH═CH ₂ ) directly bonded to the carbon atom of the alicyclic structure of the side chain of the polyether resin (ring-opening (co) polymer) thus obtained, An epoxy resin [component (a)] having a functional group represented by the above formula (1) is obtained. Epoxidation can be carried out using peracids or hydroperoxides. Examples of peracids include peroxyacid, peracetic acid, perbenzoic acid, trifluoroperacetic acid, and the like.
Further, as the hydroperoxides, for example,
Hydrogen peroxide, tert-butyl peroxide, cumene peroxide and the like can be used. The epoxidation reaction can be carried out in the presence of a catalyst, if necessary.

The vinyl group based on 4-vinylcyclohexene-1-oxide in the above ring-opening (co) polymer is epoxidized to produce the functional group represented by the above structural formula (I). In this epoxidation reaction, when the alicyclic oxirane group-containing compound or the like is present as another epoxy group-containing compound, the vinyl group contained in the compound may also be epoxidized. ) Is different from the functional group shown by.

Whether or not a solvent is used in the epoxidation reaction and the reaction temperature can be appropriately adjusted depending on the apparatus used and the physical properties of the raw materials. Depending on the conditions of the epoxidation reaction, at the same time as the epoxidation of the vinyl group in the raw material polymer, the substituent represented by the following formula (3) in the raw material and / or the generated substituent represented by the above formula (1) As a result of causing a side reaction with an epoxidizing agent or the like, a modified substituent is generated and may be mixed in the component (a).

[0061]

[Chemical 13]

The ratio of these modified substituents contained varies depending on the type of epoxidizing agent, the molar ratio of the epoxidizing agent to the vinyl group, the reaction conditions and the like.

As the component (a), commercially available products can be used, and examples thereof include EHPE3150 (trade name, manufactured by Daicel Chemical Industries, Ltd.). This is an epoxidized vinyl group in a ring-opening polymer of 4-vinylcyclohexene-1-oxide, and the average degree of polymerization is 1
It is in the range of 5 to 25.

It is sufficient that at least two epoxy group-containing functional groups represented by the formula (1) are present in one molecule of the component (a), and the component (a) is preferably 140 to 1,000.
It may have an epoxy equivalent weight of 0, more preferably in the range 170-300.

Component (b) : An amino compound used in the preparation of the cationic resin (B-1) and having a hydroxyl group (preferably a primary hydroxyl group), a secondary amino group and an amide group in one molecule.

As such an amino compound, a compound represented by the following general formula (2) is preferable.

[0067]

[Chemical 14]

In the formula, n is an integer of 1 to 6, R ₁ represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R ₂
Represents a hydroxyl group and / or a hydrocarbon group having 4 to 36 carbon atoms which may have a polymerizable unsaturated bond.

The amino compound of the above formula (2) is, for example, as shown in the following reaction formula 1, about 1 mol of N-hydroxyalkylalkylenediamine (3) and about 1 mol of carbon atoms of 5 to 37, preferably. It can be produced by adding 8 to 23 monocarboxylic acids (4).

[0070]

[Chemical 15]

In the formula, R ₁ , R ₂ and n have the same meanings as described above.

As the diamine (3) used in this reaction, for example, hydroxyethylaminoethylamine, N-hydroxyethylethylenediamine,
N-hydroxyethyl propylene diamine, N-hydroxyethyl butylene diamine, N-hydroxyethyl pentylene diamine, N-hydroxyethyl hexylene diamine, N- (2-hydroxy) propyl ethylenediamine, N- (2-hydroxy) propyl propylene diamine , N- (2-hydroxy) propyl butylene diamine, N- (2-hydroxy) propyl pentylene diamine, N- (2-hydroxy) propyl hexylene diamine, and the like. Among them, hydroxyethyl aminoethyl amine, N-hydroxy Ethyl propylene diamine is preferred.

As the monocarboxylic acid (4), for example, coconut oil fatty acid, castor oil fatty acid, rice bran oil fatty acid, soybean oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, Mixed fatty acids such as tung oil fatty acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, ricinoleic acid, linoleic acid, linoleic acid, eleostearic acid, 12-hydroxystearic acid, behenic acid And so on. Of these, stearic acid, oleic acid, 12-hydroxystearic acid and mixed fatty acids containing these acids are particularly preferable.

If the carbon number of the alkyl group of R ₁ of the diamine (3) is 3 or more, the reactivity of the hydroxyl group may be lowered. Further, when the carbon number of R ₂ of the monocarboxylic acid represented by the above general formula (4) is smaller than 4, the improvement of the smoothness of the coated surface cannot be expected so much.

The reaction of N-hydroxyalkylalkylenediamine (3) with monocarboxylic acid (4) is carried out by mixing the two components in an approximately equimolar ratio and using an organic solvent such as toluene or methyl isobutyl ketone in a prescribed amount. The reaction product water is removed, and the residual organic solvent is removed by a reduced pressure method or the like. The component (b) preferably has an amine value (secondary amino group) of generally 350 to 88, particularly 230 to 120, and a hydroxyl value of 44 to 35.
It is preferably 0, particularly in the range of 60 to 230.

Component (c) : An amino compound used in the preparation of the cationic resin (B-1) and having a primary hydroxyl group and a primary or secondary amino group in one molecule.

The component (c) is for introducing a primary hydroxyl group and a primary or secondary amino group into the component (B-1) by reacting with the component (a). Examples of the component (c) include the following compounds.

1. 1. Primary alkanolamines such as monoethanolamine, monopropanolamine, monobutanolamine; N-methylethanolamine, N-ethylethanolamine, diethanolamine, di-n (or iso)-
2. Secondary alkanolamines such as propanolamine and dibutanolamine; Addition product of the above-mentioned primary alkanolamine and α, β-unsaturated carbonyl compound (secondary alkanolamine): For example, addition product of monoethanolamine and N, N-dimethylaminopropylacrylamide, monoethanolamine 3. Addition product of hydroxyethyl (meth) acrylate, addition product of monoethanolamine and hydroxypropyl (meth) acrylate, addition product of monoethanolamine and hydroxybutyl (meth) acrylate, etc .; 4. Primary and secondary alkanolamines such as hydroxyethylaminoethylamine; Mixture (secondary alkanolamine) of at least one selected from hydroxyamine, hydroxymethylhydrazine and hydroxyethylhydrazine and a ketone compound (eg, dimethylketone, methylethylketone, methylisobutylketone, dibutylketone, dipropylketone, etc.) .

Of these, the particularly preferred component (c) is a secondary alkanolamine such as N-methylethanolamine, N-ethylethanolamine, diethanolamine, di-n (or iso) propanolamine.

Cationic resin (B-1): Obtained by reacting the above component (a) with the components (b) and (c).

The reaction between the component (a) and the component (b) can be carried out, for example, as shown in the following reaction formula 2, with a secondary amino group in the component (b) and an alicyclic epoxy group in the component (a). It is presumed that this will be done between and. The component (c) is the first
It is considered that the primary or secondary amino group reacts with the epoxy group-containing functional group in the component (a) to introduce a primary hydroxyl group and a secondary or tertiary amino group into the component (a).

[0082]

[Chemical 16]

In the formula, EP represents the skeleton portion of the epoxy resin. However, in the above formula, only one epoxy group of the epoxy group-containing functional group is shown for simplification, but it is understood that at least one other epoxy group-containing functional group is bonded to EP. Should be. And R ₁ , R ₂ and n have the same meaning as described above.

The cationic resin (B-1) thus obtained is superior in water dispersibility even with a small amount of the neutralizing agent, as compared with the one produced by the reaction with the conventional bisphenol type A epoxy resin. Therefore, the electrodeposition bath equipment is not easily corroded, and the water dispersibility and throwing power are remarkably excellent even at high pH, and further, the curability and corrosion resistance of the formed coating film are not observed at all. It has various excellent advantages.

The reaction ratios of the components (a), (b) and (c) are not particularly limited and can be arbitrarily selected according to the application of the resulting coating resin. But in general,
In the components (a) and (b), the secondary amino group in the component (b) is 0.02 to 0.5, particularly 0.1 per 1 mol of the epoxy group-containing functional group in the component (a). It is preferable to use them in a proportion of about 0.4 mol. Further, the component (a) and the component (c) are the first group in the component (c) per mol of the epoxy group-containing functional group in the component (a). It is preferable to use the primary or secondary amino group in a ratio of 0.4 to 0.98 mol, particularly 0.4 to 0.8 mol. Furthermore, the total number of moles of the component (b) and the component (c) is (a)
0.75 per mole of functional group containing epoxy group of component
It is preferably 1.1 mol, particularly preferably 0.8 to 1.0 mol.

Suitable reaction temperatures for the components (a), (b) and (c) are generally 50 to 300 ° C, particularly 70 to 200 ° C. If necessary, an alcohol-based, ketone-based, ether-based, or other organic solvent may be used in this reaction system. Further, the reaction order of the component (b) and the component (c) with respect to the component (a) is not particularly limited, and for example, both the components can be added simultaneously or before and after the components to be reacted separately.

The cationic resin (B-1) is usually
It has an amino group, an amide group and a hydroxyl group derived from the component (b), a primary hydroxyl group and an amino group derived from the component (c), and has an amine value of 30 to 150, particularly 80 to 130; a hydroxyl group. The equivalent weight is 230-800, especially 2
50 to 500; number average molecular weight is 800 to 70,000,
It is particularly preferably in the range of 1,000 to 50,000. The resin (B-1) has excellent water dispersibility, plasticity, compatibility, and good smoothness on the coated surface. It is presumed that this is due to the plasticizing effect of R _{2 in} the component (b) due to the hydrocarbon chain and the polarization due to the hydroxyl group. Moreover, the resin (B-1) does not deteriorate the corrosion resistance.

The cationic resin (B-1) can be obtained by reacting the components (a) to (c) as described above, but one molecule of phenolic hydroxyl group is further added to the components (a) to (c). A cationic resin obtained by reacting at least one phenol compound (d) therein is also included.

Component (d) : a phenol compound having at least one phenolic hydroxyl group in one molecule, which is used when preparing the cationic resin (B-1).

Specific examples of the phenol compound (d) include bis (4-hydroxyphenyl) -2,2-propane, 4,4'-dihydroxybenzophenone and bis (4-hydroxyphenyl) -1,1. -Ethane, bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butylphenyl) -2,2
-Propane, bis (2-hydroxynaphthyl) methane,
1,5-dihydroxynaphthalene, bis (2,4-dihydroxyphenyl) methane, tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4-dihydroxydiphenyl ether, 4,4-dihydroxydiphenylsulfone , Phenol novolac, cresol novolac, and other polyhydric phenol compounds.

Further, phenol, nonylphenol,
Monophenol compounds such as α- or β-naphthol, p-tert-octylphenol, o- or p-phenylphenol can also be used.

In order to form a coating film having excellent anticorrosion properties, as the component (d), particularly bisphenyl A type [bis (4-hydroxyphenyl) -2,2-propane] or bisphenol F type [bis is used. It is preferable to use a bisphenol resin such as (4-hydroxyphenyl) -2,2-methane]. Among the bisphenol resins, in particular, a number average molecular weight of at least 200, preferably about 80
A compound represented by the following formula, which is in the range of 0 to about 3,000 and contains 2 or less, preferably 0.8 to 1.2, phenolic hydroxyl groups per molecule on average. Are suitable.

[0093]

[Chemical 17]

In the formula, q is an average number of 0 to 7 and R
₂₁ represents a residue of an active hydrogen compound.

Examples of the active hydrogen-containing compound which is a precursor of R _{21 in} the above formula include amines such as secondary amines; phenols such as nonylphenol;
Examples thereof include compounds such as organic acids such as fatty acids; thiols; alcohols such as alkyl alcohol, cellosolve, butyl cellosolve, and carbitol; inorganic acids. Among these, the most preferable are dialkanolamine which is a secondary amine having a primary hydroxyl group, nonylphenol, phenylphenol, and monophenol such as phenol. In particular, when a primary hydroxyl group-containing amine is used, curability is improved, and otherwise stability is improved.

In the above formula, R ₂₁ --and-
OH is shown as bonded to each other, but both ends are R ₂₁
It does not matter even if only one of − and −OH is mixed.

Further, as the component (d), for example, 1 mol of a bisphenol A diglycidyl ether type polyepoxide having a molecular weight of 200 or more, preferably 380 to 2,000, and a molecular weight of 200 or more, preferably 200 ~
1 mol of bisphenol A polyphenol in the range of 2,000 and 1 mol of a compound having active hydrogen (for example, one or more kinds selected from secondary dialkanolamine, monophenol, and the component (b)), If necessary, those obtained by reacting at a temperature of 30 to 300 ° C., preferably 70 to 180 ° C. in the presence of a catalyst and a solvent can also be used. These reaction molar ratios are merely examples and are not limited to these, and can be arbitrarily selected.

Further, as the component (d), dimer diol,
Polyols such as ethylene glycol, propylene glycol and butylene glycol; polyether glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol; polyester polyols such as polycaprolactone; polycarboxylic acids; polyisocyanates; monoisocyanates; Oxides of unsaturated compounds such as ethylene oxide, propylene oxide, butylene oxide and styrene oxide; hydroxyl groups such as allyl glycidyl ether, polypropylene glycol diglycidyl ether, 2-ethylhexyl glycidyl ether, methyl glycidyl ether, butyl glycidyl ether and phenyl glycidyl ether A glycidyl ether of a compound having a group of organic acids such as fatty acids Glycidyl ester; those obtained by reacting an alicyclic oxirane-containing compounds, can also be used as component (d). Furthermore, in such compounds, δ-
Graft-polymerized 4-caprolactone, an acrylic monomer or the like can also be used.

Using the component (d), a cationic resin (B-
In the preparation of 1), the method of reacting the components (a) with the components (b) and (c) can be carried out in the same manner as described above. Further, it is speculated that in the component (d), the phenolic hydroxyl group in the component forms a ether bond by ring-opening reaction with the epoxy group-containing functional group in the component (a). The ratio of each of these components can be arbitrarily selected according to the intended use of the resulting cationic resin (B-1) and the like, but in general, per 1 mol of the epoxy group-containing functional group in the component (a), The secondary amino group in the component (b) is 0.0
2 to 0.5 mol, particularly 0.1 to 0.4 mol, and the primary or secondary amino group in the component (c) is 0.3 to 0.98 mol, particularly 0.4 to 0.9 mol. , And the phenolic hydroxyl group in the component (d) is 0.02 to 0.4 mol, particularly 0.1.
It is preferable to use it in a ratio within the range of to 0.3 mol. And the total of the above-mentioned number of moles of the components (b), (c) and (d) is 0.75 to 1.5 moles, especially 0.8 to 1 mole, per 1 mole of the epoxy group-containing functional group in the component (a). It is preferably in the range of 0.2 mol.

The reaction using each of these components can be carried out in the same manner as described above, and the reaction temperature is, for example, 50 to 3
00 ° C, especially 70-200 ° C, is suitable. The reaction order is not particularly limited, and all the components may be charged at the same time for reaction, or each of the other components may be added to the component (a) in any order and the reaction may be sequentially performed. For example, (a)
The component is first reacted with the component (d), and then the components (b) and (c) are reacted, or the raw material of the component (d), polyepoxide and polyphenol, is reacted with (a).
When the component is allowed to exist in the system in which the component (b) and / or the component (c) is reacted, the production of the component (d) itself and the addition reaction to other components are simultaneously carried out. This is convenient because the process can be omitted. It is also possible to excessively blend the component (D), react the components (a) with the components (b) and (c), and then react the unreacted component of the component (d) with another polyepoxide. .

A cationic resin containing the component (d) (B-
1) generally has an amine value of 20 to 150, especially 35 to 1
00; hydroxyl equivalent is 250 to 1,000, especially 300 to
700; The number average molecular weight is preferably 800 to 150,000, particularly preferably 1,000 to 60,000.

In the resin (B-1), (a)-
By using the component (d) in addition to the component (c), the hydrophobic property and the compatibility with other resin components are further improved. Further, the portions to which the components (b) and (c) are added have strong hydrophilicity and basicity. Therefore, when the component (d) is used in combination, the hydrophobic part and the hydrophilic part are co-polarized, so that the dispersibility with other resins is extremely excellent.

The component (a) is a cationic resin (B-1).
The water dispersibility and throwing power of the resin can be remarkably improved even if the resin is contained in a small amount. Therefore,
The content of the component (a) in the cationic resin (B-1) includes the component (a), the component (b) and the component (c), and also the component (d) when it is used. Based on the total amount, 0.5 to 95% by weight, preferably 3 to
The basic group of the cationic resin (B-1), which is preferably in the range of 75% by weight, more preferably 5 to 50% by weight, can be protonated with an acidic compound and dissolved or dispersed in water.

Examples of the acidic compound include water-soluble organic carboxylic acids such as formic acid, acetic acid, glycolic acid and lactic acid. These can be made water-dispersible or water-soluble by reacting with a basic group in the above-mentioned cationic resin (B-1) to be protonated. Cationic resin (B-1)
The amount of the acidic compound to be reacted with is preferably within a range in which the reaction product can be stably dispersed or dissolved in water, and is as small as possible. In particular, the neutralization value is KOH (mg
/ g solid content) generally in the range of 3 to 200, especially 5 to 180
The neutralization number may be less than 3 as long as it can be uniformly dispersed in water by adding a surfactant and the stability of the dispersion is excellent. Absent. The pH of the aqueous solution or dispersion of the cationic resin (B-1) is preferably 4-9, particularly 6-7.

In the present invention, the electrodeposition deposition rate of the above component (A) needs to be slower than that of the component (B-1), and the method for adjusting this rate is not particularly limited, but these components can be adjusted. It can be easily carried out by changing the composition of the amino compound used for the preparation and the amine value of both components.

Specifically, the following method is preferable.

Composition of amino compound Component (A) using a secondary alkanolamine and component (B-1) using an amino compound having a primary hydroxyl group and a primary amino group (primary alkanolamine). When compared with, a primary alkanolamine was used (B-1)
The electrodeposition rate of the component is faster than that of the secondary alkanolamine (component A). By using such an amino compound, at a current density of 0.5 mA / cm ² ,
The electrodeposition deposition rate of component (A) is 120 to 300 seconds, and (B-
It may be necessary to include that of component 1) in 50 to 120 seconds and the difference between both components in the range of 50 seconds or more, especially 60 to 150 seconds. In this case, the amine value of both components is 40-8.
The difference is found even when fixed to 0, especially 50 to 70 (mgKOH / g).

Amine Value (A) Component (A) has a secondary alkanolamine and has an amine value of 30 to 100, especially 50 to 70 (mgKOH / g).
In the component (B-1), the amine value is 60 to 120, particularly 70 to 100 (mgKOH / g) by using the components (b) and (c).
Then, by adjusting the difference in amine value between the component (B-1) and the component (A) to be 10 or more, particularly 20 to 50, the electrodeposition deposition rate of both components is within the above range. Can be included in.

The component (B) used in the present invention is obtained by mixing and dispersing the pigment (B-2) in the aqueous solution or dispersion of the cationic resin (B-1).

The ratio of both components is in the range of 10 to 50 parts by weight, preferably 20 to 40 parts by weight, per 5 parts by weight of the resin solid content of the component (B-1).
Specifically, water is added and adjusted so that the solid content of the component (B) at the time of mixing and dispersing is about 35 to 52% by weight, particularly preferably about 40 to 50% by weight. By mixing and dispersing with a sand mill etc. (B)
The ingredients are obtained. It is preferable that the particle size of the component (B) after dispersion by a tube gauge is 10 μm or less.

As the pigment (B-2), for example, coloring pigments such as carbon black, titanium white, lead white, lead oxide and red iron oxide: extenders such as clay and talc: strontium chromate, lead chromate, Basic lead chromate, red lead, lead silicate, basic lead silicate, lead phosphate, basic lead phosphate, lead tripolyphosphate, lead silicochromate, yellow lead, cyanamide lead, lead zincate, lead sulfate, Anticorrosion pigments such as basic lead sulfate: These alone or 2
The above can be used together.

Component (c): Curing Agent The component (c) is used to three-dimensionally crosslink and cure the components (A) and (B-1) by heating, and specifically, a blocked polyisocyanate compound is suitable. .

The blocked polyisocyanate is obtained by reacting a polyisocyanate with a blocking agent, and examples of the polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate and 1,2-propylene. Aliphatic diisocyanates such as diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate; 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,2-cyclohexane diisocyanate, Alicyclic diisocyanates such as isophorone diisocyanate; m-phenylene diisocyanate, p-phenylene diisocyanate Over door, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate,
Aromatic diisocyanates such as 1,4-naphthalene diisocyanate; 4,4'-diphenylene methane diisocyanate, 2,4- or 2,6-tolylene diisocyanate or mixtures thereof, 4,4'-toluidine, 1,4- Aroma such as xylylene diisocyanate-
Aliphatic diisocyanate; dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate,
Heterocyclic diisocyanates such as chlorodiphenylene diisocyanate; triphenylmethane-4,4 ', 4 "
Triisocyanates such as triisocyanate, 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene; 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate, etc. Tetraisocyanate; polyisocyanate polymers such as toluene diisocyanate dimers and trimers; and alcohols such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol, glycerin, pentaerythritol, and tripropylene glycol in excess of these polyisocyanates. Low molecular weight polyethers such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxydecamethylene glycol Triol ethers or by reacting the low molecular weight active hydrogen-containing compounds such as low molecular weight polyester polyols obtained polyisocyanate (prepolymer) can be mentioned.

Examples of the blocking agent capable of reacting with the polyisocyanate include phenols such as phenol, m-cresol, xylenol and thiophenol; methanol, ethanol, butanol, 2-ethylhexanol, cyclohexanol, nonyl alcohol, Alcohols such as phenylcarbinol and chloroethanol; Tertiary hydroxylamines such as diethylethanolamine; Oximes such as methylethylketoxime, acetoxime, cyclohexanooxime;
Examples thereof include active hydrogen-containing compounds such as caprolactam, ethyl acetoacetate and diethyl malonate. Among the above-mentioned block polyisocyanates, preferred examples include isophorone diisocyanate methyl ethyl ketoxime block, 4,4-diphenylene methane diisocyanate 2-ethyl hexanol block, and 1,4-xylylene diisocyanate methyl ethyl ketoxime block.

Further, as a curing agent, JP-A-2-255 can be used.
Epoxy resins having an average of two or more epoxy group-containing functional groups formed by bonding an epoxy group to an alicyclic skeleton and / or a bridged alicyclic skeleton described in Japanese Patent No. 874 can also be used.

The cationic electrodeposition coating composition of the present invention comprises the above components (A), (B) and (C) as the main components,
These constituent ratios are not particularly limited and can be arbitrarily selected according to the purpose. Specifically, the component (A) and the component (C) are based on the total amount of both components, and the component (A) is Is 50-9
0% by weight, particularly 65 to 85% by weight, the component (C) is 50 to 50% by weight.
10% by weight, especially 35 to 15% by weight is preferred. Also,
The component (B) is 100 in total of the components (A) and (C).
3 to 10 parts by weight, particularly 3 to 6 parts by weight, and 10 to 50 parts by weight, especially 20 to 40 parts by weight of the component (B-2) are suitable per part by weight.

The cationic electrodeposition coating composition of the present invention contains the above-mentioned components (A), (B) and (C) as essential components, and further contains additives such as a catalyst, a dispersant and an cissing inhibitor as necessary. can do.

The cationic electrodeposition coating composition of the present invention can be subjected to cationic electrodeposition coating on a conductive substrate surface-treated with zinc phosphate, iron phosphate or the like if necessary, and the thickness of the coating film is not particularly limited. However, generally, a range of 3 to 200 μ is suitable based on the cured coating film, and the coating film can be heat-cured at a temperature of, for example, 70 to 250 ° C., preferably 120 ° C. to 160 ° C. it can.

The cationic electrodeposition coating of the cationic electrodeposition coating composition of the present invention can be carried out by a method known per se. For example, the solids content of the bath is 5-40% by weight, preferably 10-25% by weight and the pH is 5-8, preferably 5.5.
Prepared in the range of ~ 7, bath temperature 20-35 ℃, preferably 25-30 ℃; current density (direct current) 0.005-5
A / cm ^2, preferably 0.01~2A / cm ^2; Voltage 10-5
00 V, preferably 100 to 300 V; and energization time of 0.5 to 5 minutes, preferably 2 to 3 minutes.

After electrodeposition coating, the article to be coated can be lifted from the electrodeposition bath and washed with water, and then the water contained in the electrodeposition coating film can be removed by a drying means such as hot air.

The electrodeposition coating film thus formed using the cationic electrodeposition coating composition of the present invention can be heat-cured as described above.

Particularly in the coating of the cationic electrodeposition coating composition of the present invention, it is preferable that the component (B) is preferentially deposited on the surface to be coated earlier than the component (A), and then the component (A) is deposited. That is, in the structure of the electrodeposition coating film, it is preferable that the surface to be coated is composed mainly of the component (B) and the outside thereof is composed mainly of the component (A). For that purpose, it is preferable to perform the energization method at the time of electrodeposition coating as follows.

1) Initially, a low voltage (eg, 100 V or less, preferably 10 to 50 V) is energized for a certain period of time, and thereafter, for example, 100 V or more, preferably 150 to 250.
The voltage is increased to V before energization.

2) The voltage is gradually (for example, 4 to 8 V / second) gradually raised to about 150 to 250 V to energize for electrodeposition.

When current is applied in this manner, the component (B) is mainly deposited on the surface to be coated, and then the component (A) is deposited to form the coating film intended by the present invention.

[0126]

EFFECTS OF THE INVENTION A cured coating film excellent in both edge cover and coating surface smoothness can be obtained, and further, the pigmented settling hardly occurs, so that the finished appearance (smoothness etc.) of the electrodeposition coating film is improved, The bathing stability and electrodeposition characteristics were also good.

Examples and comparative examples relating to the present invention will be shown below. All parts and percentages are in principle by weight.

I Production Example 1. Component (A) Component (A-1): EHPE-3150 was added to a flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser.
(Epoxy equivalent 180, manufactured by Daicel Chemical Industries, Ltd.) 9
00 parts, ethylene glycol monobutyl ether 200
Parts, 315 parts of diethanolamine, and 370 parts of an amino compound (the following (Note 1)) were charged, gradually heated and dissolved while mixing and stirring, and reacted at 140 ° C. After confirming that the epoxy equivalent became 1,585, Bisphenol A
2,052 parts was added and the mixture was reacted at 150 ° C. for 5 hours, and it was confirmed that the residual amount of epoxy group was 0. Then, 420 parts of diethanolamine, 4,370 parts of bisphenol A diglycidyl ether having an epoxy equivalent of 190, 740 parts of an amino compound (the following (Note 1)) and 2,092 parts of ethylene glycol monobutyl ether were added, and the mixture was reacted at 150 ° C. for 5 hours. Confirm that the residual epoxy group is 0, solid content 80%, amine value 61, primary hydroxyl equivalent 540
The cationic resin (A-1) of was obtained.

(Note 1) A reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a water separator was charged with 285 parts of stearic acid, 104 parts of hydroxyethylaminoethylamine and 80 parts of toluene and gradually mixed and stirred. After heating, the toluene was removed as needed, and 18 parts of the reaction water was separated and removed while raising the temperature, and then the remaining toluene was removed under reduced pressure to obtain an amino compound having an amine value of 150 and a freezing point of 76 ° C.

Component (A-2): A flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser is equipped with 397 parts of ethylene glycol monobutyl ether and EHPE-3.
150 (Epoxy equivalent 180, Daicel Chemical Industries, Ltd.)
Manufactured) 900 parts, amino compound (note 2) 370 parts, diethanolamine 315 parts and monophenol compound (note 3) 1,651 parts, and mixed at 150 ° C. with stirring.
The temperature was raised to 0 and the reaction was continued until the residual amount of the epoxy group became zero. Furthermore, bisphenol A diglycidyl ether with an epoxy equivalent of 190, 610 parts, bisphenol A1,
596 parts, 525 parts diethanolamine and 1,433 parts ethylene glycol monobutyl ether were added,
The reaction was carried out at 150 ° C. until the residual amount of epoxy groups became 0, to obtain a cationic resin (A-2) having a solid content of 80%, an amine value of 65 and a primary hydroxyl group equivalent of 455.

(Note 2) 300 parts of 12-hydroxystearic acid, 104 parts of hydroxyethylaminoethylamine and 80 parts of toluene were charged into a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser and a water separator, and mixed and stirred. While gradually heating to remove toluene as necessary and separating and removing 18 parts of reaction water while raising the temperature, residual toluene was removed under reduced pressure to obtain an amino compound having an amine value of 148 and a freezing point of 69 ° C.

(Note 3) 105 parts of diethanolamine, 760 parts of bisphenol A diglycidyl ether having an epoxy equivalent of 190, and bisphenol A 456 were placed in a flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser.
Parts and ethylene glycol monobutyl ether 330
Parts were added, and the reaction was carried out at 150 ° C. until the residual amount of epoxy groups became 0, and a monophenol compound having a solid content of 80% was obtained.

2. (B-1) component (B-1-) component: 463 parts of ethylene glycol monobutyl ether, EHPE-3150 in a flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser.
(Epoxy equivalent 180, manufactured by Daicel Chemical Industries, Ltd.) 9
00 parts, 740 parts of amino compound (above (Note 2)), 210 parts of diethanolamine and 1,651 parts of monophenol compound (above Note 3) were added, while mixing and stirring.
The temperature was raised to 150 ° C. and the reaction was continued until the residual amount of the epoxy group became 0 to obtain a cationic resin (B-1-) having a solid content of 80%, an amine value of 88 and a primary hydroxyl group equivalent of 396.

Component (B-1-): A flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser was charged with 396 parts of ethylene glycol monobutyl ether and EHPE.
-3150 (Epoxy equivalent 180, manufactured by Daicel Chemical Industries, Ltd.) 900 parts, amino compound (the above (Note 2)) 3
70 parts, 315 parts of diethanolamine and 1,651 parts of monophenol compound (Note 3 above) were added, and the mixture was stirred and heated to 150 ° C. to react until the residual amount of the epoxy group became 0, and the solid content was 80%. A cationic resin (B-1-) having an amine value of 88 and a primary hydroxyl group equivalent of 396 was obtained.

3. Component (B) Component (B-A): Cationic resin (B-1-) as solid content 5 parts, 10% acetic acid 2.6 parts, titanium oxide 17
Parts, carbon black 0.3 parts, basic lead silicate 2 parts and refined clay 8 parts by weight, and water having a solid content of 43
% So that it was dispersed by a ball mill. The particle size with a tube gauge was 8 μm or less.

Component (B-B): Cationic resin (B-1)
-) As solid content 2.5 parts, 10% acetic acid 2.6 parts,
17 parts of titanium oxide, 0.3 part of carbon black, 2 parts of basic lead silicate and 8 parts by weight of refined clay, and water were further added so as to have a solid content of 43% and dispersed by a ball mill. The particle size with a tube gauge was 8 μm or less.

4. Component (C) Component (C-1): 222 parts of isophorone diisocyanate was charged into a reaction vessel and the reaction temperature was adjusted to 30 to 4 by external cooling.
While maintaining the temperature at 0 ° C., 226 parts of methylethylketoxime was gradually added dropwise to synthesize a blocked polyisocyanate.

II Examples and Comparative Examples Example 1 87.5 parts of (A-1) obtained in the preparation example, 33.3 parts of (C) and 16.0 parts of 10% acetic acid were mixed, and the mixture was removed with stirring. Ionized water was added to obtain 285.7 parts of an emulsion having a solid content of 35%. Then, add 7 parts of pigment paste B-a.
5.1 parts and deionized water were added to obtain a cationic electrodeposition paint having a solid content of 20%.

Example 2 A cationic electrodeposition coating composition was obtained in the same manner as in Example 1 except that (A-2) obtained in Production Example was used.

Example 3 A cationic electrodeposition coating composition was obtained in the same manner as in Example 1, except that the pigment paste B-B was used.

Comparative Example 1 900 parts of EHPE3150 was dissolved by heating with 407 parts of ethylene glycol monobutyl ether, and then an acid value of 200 was obtained.
280 parts of tall oil fatty acid are added and reacted at 170 ° C. until the acid value becomes 0, then cooled to 80 ° C., 185 parts of amino compound, 262.5 parts of diethanolamine, 1,732 parts of monophenol compound (Note 4) Was added and reacted at 150 ° C. for 5 hours to obtain a cationic resin having a solid content of 80%, an amine value of 56, and a primary hydroxyl group equivalent of 548.

5 parts by weight of this cationic resin, 17 parts of titanium oxide, 0.3 part of carbon black, 2 parts of basic lead silicate and 8 parts of refined clay, and a deionized water content of 43%. To obtain a pigment paste B-ha dispersed in a ball mill. The particle size with a tube gauge was 8 μm or less. A cationic electrodeposition coating composition was obtained in the same manner as in Example 1 except that this pigment paste (B-C) was used.

(Note 4) A flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser was equipped with 170 parts of phenylphenol, 760 parts of bisphenol A diglycidyl ether having an epoxy equivalent of 190, and bisphenol A456.
Part, 0.2 parts of tetramethylammonium chloride and 346 parts of ethylene glycol monobutyl ether, and reacted at 150 ° C. until the residual amount of epoxy group becomes 0,
The solid content was adjusted to 80%.

Comparative Example 2 The solid content of (A-1) obtained in Production Example was 5 parts, titanium oxide was 17 parts, carbon black was 0.3 part, and basic lead silicate 2 was used.
Parts and 8 parts of purified clay, and deionized water were further added so that the solid content was 43% to obtain B-ni dispersed in a ball mill. The particle size of the tube gauge was 8 μm or less. A cationic electrodeposition coating composition was obtained in the same manner as in Example 1 except that this pigment paste (B-D) was used.

Examples 4 to 8 and Comparative Examples 3 to 5 The cationic electrodeposition coating compositions obtained in the above Examples and Comparative Examples were used to carry out electrodeposition coating under the electric current conditions shown in Table 1 below. As the article to be coated, a zinc phosphate treated steel plate and a cutter blade were used. The electrodeposited coating film was heated at 170 ° C. for 30 minutes to be cured.

[0146]

[Table 1]

In Table 1, * 1) Electrodeposition deposition rate: The cationic resin itself of each component was measured at a current density of 0.5 mA / cm ² .

* 2) Energization condition Y: After energizing at 10V for 60 seconds, immediately increase the voltage to 240V and energize for 180 seconds. Z: Increase the voltage by 4V per second, 240V in 60 seconds
And then energize for 120 seconds.

* 3) Test Method Coating Melt Viscosity: The melt viscosity of the electrodeposited coating film during baking is evaluated from the thermal fluid appearance of scratches by comparison with the rolling ball viscosity measuring method (according to JIS-Z-0237). did. The numerical value indicates the lowest viscosity (centipoise).

End face coverage: The cutter blade after electrodeposition coating is evaluated for corrosion resistance at the edge portion after 240 hours by JIS Z2371 salt spray test. ◎: No rust occurred ○: Slight rust occurred △: Rust occurred considerably ×: Rust occurred significantly

Smoothness of coated surface: The finish of the electrodeposition coated surface is visually evaluated. ◎: Good ○: Almost good △: Somewhat bad

Salt spray resistance: A cross-cut flaw was made with a knife to the electrodeposition coating film so as to reach the base, and this was JIS
Adhesive cellophane tape peeling test of the cross-cut part after 840 hours salt spray test by Z2371. ◎: Almost no peeling ○: Little peeling is observed ×: Significant peeling is recognized

Impact resistance: JIS K5400-1979
According to the method of 6.13.3B, it is performed in an atmosphere of 20 ° C. It shows the maximum height (cm) at which the coating film is not damaged under the condition that the weight is 500 g and the tip diameter of the hammer is 1/2 inch. 5
The maximum value was 0 cm.

Secondary adhesion in warm water immersion: After immersion in 40 ° C. water for 20 days, JIS K5400-1979 6.15
According to the above, make a rugged pattern on the coating film, attach an adhesive cellophane tape on the surface, and evaluate the coated surface after it is rapidly peeled off. ◎: Good without any abnormality ○: Slight edge peeling of the edges

Claims (2)

[Claims] 1. A base resin having a hydroxyl group and a cationic group, which is obtained by reacting an epoxy group-containing resin with a secondary alkanolamine, and (B) one molecule of the following formula (1): (In the formula, m is an integer of 2 to 4) The epoxy resin (a) having at least two epoxy group-containing functional groups has a hydroxyl group, a secondary amino group and an amide group in one molecule. Which is obtained by reacting the amino compound (b) and the amino compound (c) having a primary hydroxyl group and a primary or secondary amino group in one molecule, and the electrodeposition rate of which is higher than that of the component (A). Pigment (B-2) using the cationic resin (B-1) adjusted so that it no longer exists
And (C) a curing agent as a main component, a cationic electrodeposition coating composition. 2. A conductive coating object is immersed as a cathode in an electrodeposition bath containing the cationic electrodeposition coating composition according to claim 1 as a main component, and an electric current is applied between it and the anode. ) The component is deposited, and then the component (A) is deposited. A cationic electrodeposition coating method characterized in that