JPH04279679A - Production of cationic electrodeposition paint - Google Patents

Abstract

PURPOSE:To obtain the subject paint excellent in shelf life and surface smoothness and capable of forming a thick coating film even on a corner part, etc., by making an organic solution of a curable resin aquatic using an aqueous dispersion of cationically electrodepositable fine gelled polymer particles, and subsequently further adding said aqueous dispersion thereto. CONSTITUTION:(A) An organic liquid of a curable resin prepared by dissolving or dispersing (i) a cationic resin preferably composed of an amine-added epoxy resin and (ii) a blocked polyisocyanate compound in an organic solvent is made aquatic by using (B) an aqueous dispersion of cationically electrodepositable fine gelled polymer particles to obtain an aqueous dispersion. The component (B) is subsequently further added thereto, thus obtaining the objective coating material. In addition, as an example of the component (B), an aqueous dispersion of fine gelled particles prepared by emulsion polymerization in the presence of a cationically reactive emulsifier or an aqueous dispersion of fine gelled intraparticle crosslinked particles containing colloidal silica is exemplified.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is particularly concerned with paint storage stability,
The present invention relates to a method for producing a cationic electrodeposition paint that has excellent coating film smoothness and can form a thick coating film even on edge portions such as corners and protrusions.

0002

2. Description of the Related Art Electrodeposition coating has excellent throwing power and uniformity of film thickness, and is widely used as an undercoat for automobile bodies. However, deposited coatings formed by electrodeposition generally have a drawback of lacking smoothness due to the effects of gas generation during electrodeposition and high solid content (low solvent content).

[0003] As a method for improving the smoothness, it has been proposed to cause the electrodeposited coating to melt and flow during baking to harden the coating. In particular, cationic electrodeposition paints generally have extremely low molten coating viscosity, and as a result, the smoothness is improved by the above method, but on the other hand, the coating film tends to melt and flow, so that most of the cured coating film is left at the edges. This results in a defect in which the rust prevention properties of those parts are significantly inferior.

0004

[Problems to be Solved by the Invention] Conventionally, in order to improve the rust prevention properties of the edge portions, for example, rust-proof steel plates have been used, or anti-corrosion paint has been applied to the edge portions with a roller or brush. However, the cost and number of steps are enormous. In addition, various attempts have been made to improve the rust prevention properties of the edges, such as adding a large amount of pigment to the electrodeposition paint and reducing the amount of plasticizing ingredients. There is a strong demand for the development of a cationic electrodeposition coating that satisfies both of these properties, without being compatible with formability.

[0005]

[Means for Solving the Problems] Therefore, the present inventors have conducted extensive research with the aim of developing a cationic electrodeposition paint with excellent edge coverage and coated surface smoothness. A cation obtained by aqueousizing an organic solution obtained by dissolving or dispersing a component of a polyisocyanate compound in an organic solvent with an aqueous dispersion of a cationically electrodepositable gelling fine particle polymer, and then adding the aqueous dispersion. Electrodeposition paints do not impair bath stability, electrodeposition properties, water resistance, corrosion resistance, etc. of the paint film, and the decrease in melt viscosity during baking hardening of the electrodeposition paint film is controlled, resulting in smoothness of the painted surface and edge coverage. The present inventors have discovered that the present invention is a cationic electrodeposition paint that provides excellent performance in both properties and has completed the present invention.

That is, the present invention provides an aqueous solution of a curable resin organic solution prepared by dissolving or dispersing a cationic resin and a blocked polyisocyanate compound in an organic solvent with an aqueous dispersion of a cationically electrodepositable gelatinized fine particle polymer. The present invention relates to a method for producing a cationic electrodeposition coating material, which further comprises adding the cationic fine particle polymer aqueous dispersion to the aqueous dispersion after obtaining the compound.

The cationic resin of the curable resin composition used in the present invention is a cationic resin that can be cured with isocyanate, and may be any conventionally known resin such as epoxy resin, acrylic resin, polybutadiene, or alkyd resin. Although it is also possible to use epoxy resins, amine-added epoxy resins are preferred from the viewpoint of corrosion resistance.

Examples of the amine-added epoxy resin include conventionally known adducts of (I) polyepoxide compounds with primary mono- and polyamines, secondary mono- and polyamines, or mixed primary and secondary polyamines (for example, (see U.S. Pat. No. 3,984,299); (II) adducts of polyepoxide compounds with secondary mono- and polyamines having ketiminated primary amino groups (e.g., U.S. Pat. No. 4,017,438); (See specification); (III) Reactants obtained by etherification of a polyepoxide compound and a ketiminated hydroxy compound having a primary amino group (see, for example, JP-A-59-43013). .

The amine-added epoxy resin may be of a type that has a blocked isocyanate group in the resin molecule and self-crosslinks without the need for a crosslinking agent;
Alternatively, the resin may be of an external crosslinking type that does not have a blocked isocyanate group in the resin and contains a blocked isocyanate compound as a crosslinking agent in the resin composition.

The polyepoxide compound used in the production of the amine-added epoxy resin is a compound having two or more epoxy groups in one molecule, and generally has at least 20 epoxy groups.
0, preferably 400 to 4,000, more preferably 8
Those having a number average molecular weight within the range of 00 to 2,000 are suitable, and those obtained by the reaction of polyphenol compounds and epichlorohydrin are particularly preferred.

[0011] Examples of the polyphenol compound that can be used to form the polyepoxide compound 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-tert-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-dihydroxydiphenylsulfone, phenol novolak, cresol novolak, and the like.

The polyepoxide compound may be partially reacted with a polyol, polyether polyol, polyester polyol, polyamide amine, polycarboxylic acid, polyisocyanate compound, etc., and may also be reacted with ε-caprolactone, acrylic monomer, etc. It may also be obtained by graft polymerization.

The blocked isocyanate compound used for introducing a blocked isocyanate group into the resin molecule or as an external crosslinking agent is a stoichiometric amount of a polyisocyanate compound and an isocyanate blocking agent (for example, an alcohol compound, an oxime compound, It is an addition reaction product with phenolic compounds, etc.). Examples of the polyisocyanate compound include tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, and bis(methyl isocyanate).
Aromatic, cycloaliphatic, and aliphatic polyisocyanate compounds such as cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, and isophorone diisocyanate, and excess amounts of these polyisocyanate compounds include ethylene glycol, propylene glycol, and trimethylolpropane. Examples include terminal isocyanate-containing compounds obtained by reacting low-molecular active hydrogen-containing compounds such as , hexanetriol, and castor oil.

[0014] Furthermore, as the above-mentioned acrylic resin,
For example, aminoethyl (meth)acrylate, N,N-
Methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl(
C1-12 alkyliesters of (meth)acrylic acid such as meth)acrylate, 2-ethylhexyl (meth)acrylate; hydroxyethyl (meth)acrylate;
C1-4 hydroxyalkyl esters of (meth)acrylic acid such as hydroxypropyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid; styrene and its derivatives (e.g. α-methylstyrene), (meth)acrylonitrile, α such as butadiene
, using a β-ethylenically unsaturated monomer as necessary,
Examples include those obtained by (co)polymerization according to conventional methods.

[0015] In the curable resin composition used in the present invention, it is preferable to use an alkyl tin ester compound of an aromatic carboxylic acid as a dissociation catalyst. The compound is of a liquid type that can be uniformly mixed in the cationic resin component or in the mixed varnish during water solubilization, and does not cause abnormalities in the stability of the paint or the condition of the coated surface.

As such an alkyltin ester compound of an aromatic carboxylic acid, an aromatic carboxylic acid ester of alkyltin can be used without particular restriction, but the number of carbon atoms in the alkyl group of the alkyltin is preferably 10 or less. Moreover, as the aromatic carboxylic acid, benzoic acid and substituted benzoic acid are preferable. Typical examples of alkyltin ester compounds of aromatic carboxylic acids include dioctyltinbenzoateoxy, dibutyltinbenzoateoxy, dioctyltin dibenzoate, dibutyltin dibenzoate, etc. represented by the following formulas.

[0017] The amount of the liquid tin catalyst to be used can be selected depending on the performance required of the electrocoating paint, but generally it is based on 100 parts by weight of resin solid content in the electrocoat composition. It ranges from 0.1 to 10 parts by weight, preferably from 0.2 to 5 parts by weight.

By blending the liquid tin compound into the electrodeposition paint, the compatibility with the resin for the electrodeposition paint, especially the epoxy resin, is dramatically improved, and there is no coating film abnormality such as repellency or spots, and there is no problem with aging. Not only does the catalytic effect not be lost, but the corrosion resistance of the electrodeposition coating can also be improved.

In the present invention, an aqueous dispersion of a cationically electrodepositable gelling fine particle polymer used to make the curable resin composition aqueous (hereinafter sometimes simply referred to as "gelling fine particle aqueous dispersion") is a patent application filed by the present applicant, JP-A-2-
47173 and JP-A-2-64169 can be used.

For example, (a) a polymerizable unsaturated vinyl silane monomer containing a vinyl double bond and a hydrolyzable alkoxysilane group, and (b) containing at least two radically polymerizable unsaturated groups in the molecule. (c) a polymerizable unsaturated monomer containing a vinyl double bond and a hydroxyl group, and (d) another polymerizable unsaturated monomer, a cationic reactive emulsifier containing an allyl group in the molecule. An aqueous dispersion of gelled microparticles obtained by emulsion polymerization with a mixture of an acrylic copolymer containing a hydrolyzable alkoxysilane group and a cationic group, and cationic acidic colloidal silica is water-dispersed, and intra-particle crosslinking is carried out. Examples include an aqueous dispersion of gelled fine particles containing colloidal silica.

[0021] The above (a) forming the former gelled fine particles
Examples of vinylsilane monomers include vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-
methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, and vinyltriacetoxysilane, and among these, γ-methacryloxypropyltrimethoxysilane is preferred.

The polymerizable monomer (b) is a polymerizable unsaturated monocarboxylic acid ester of polyhydric alcohol;
These include polymerizable unsaturated alcohol esters of polybasic acids and aromatic compounds substituted with two or more vinyl groups, such as ethylene glycol di(meth)acrylate, 1,6-hexanediol diacrylate, etc. ,
Examples include diallylphthalate and divinylbenzene.

The polymerizable unsaturated monomer containing a vinyl double bond and a hydroxyl group (c) is a monomer component that introduces a hydroxyl group into the gelled fine particle polymer, and the hydroxyl group is used for producing the gelled fine particle polymer. It functions as a hydrophilic group or a functional group for a crosslinking reaction between dispersed particles. Examples of the unsaturated monomer include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and the like.

The other polymerizable unsaturated monomer (d) is the remaining component constituting the gelled fine particle polymer,
For example, methyl (meth)acrylate, ethyl (meth)
(such as acrylate, propyl (meth)acrylate)
Alkyl (C1 to C18) esters of meth)acrylic acid; vinyl aromatic monomers such as styrene, α-methylstyrene, and vinyltoluene; amide compounds of (meth)acrylic acid; and ordinary acrylic resins such as (meth)acrylonitrile; Known monomers used in synthesis can be used.

The monomer (a) constituting the gelled fine particles
) to (d) are as follows: (a) Monomer: 1 to 30% by weight, preferably 3 to 20% by weight
Weight% (b) Monomer: 1 to 30% by weight, preferably 3 to 20% by weight
Weight% (c) Monomer: 1-30% by weight, preferably 3-20
Weight% (d) Monomer: 10-97% by weight, preferably 40-97% by weight
It is in the range of 91% by weight.

Further, as a representative cationic reactive emulsifier containing an allyl group in the molecule, the following formula (
I)

[0027]

[Chemical formula 1]

There is a reactive emulsifier containing a quaternary ammonium salt represented by: This product is known (Japanese Unexamined Patent Publication No. 60-78947) and is commercially available as Latemul K-180 (trade name, manufactured by Kao Corporation).

The amount of the cationic reactive emulsifier containing an allyl group used is usually 0.1 to 30% by weight, preferably 0.5 to 5% by weight, based on 100 parts by weight of the solid content of the gelled fine particles.
It is recommended to use within the range of .

The copolymerization of the unsaturated monomers (a) to (d) above can be carried out by emulsion polymerization, which is a known method for producing acrylic copolymers. The above monomer mixture is reacted in an aqueous medium in the presence of a cationic reactive emulsifier containing an allyl group and a water-soluble azoamide compound polymerization initiator at a reaction temperature of usually about 50 to about 100°C for about 1 to about 20 hours. This can be done by continuing.

Gelled microparticles typically have a resin solids content of about 10-40% by weight of the aqueous dispersion, based on total weight. The particle size of the gelled fine particles is 500 nm or less, preferably 10 to 300 nm, more preferably 50 to 100 nm.
It is m. The particle size can be adjusted by adjusting the amount of the cationic reactive emulsifier containing an allyl group in the molecule, and a desired range can be easily obtained.

In addition to the above monomers (a), (c) and (d), the colloidal silica-containing gelling fine particles also contain a polymerizable unsaturated monomer containing a vinyl double bond and a cationic group ( e) [For example, dialkyl (C1-6
) aminoalkyl (C1-6) (meth)acrylate] in the following blending ratio: (a) Monomer: 1 to 30% by weight, preferably 3 to 20% by weight.
Weight% (e) Monomer: 5-30% by weight, preferably 5-25
Weight% (c) Monomer: 0-30% by weight, preferably 5-20
Weight% (d) Monomer: 10-94% by weight, preferably 35-94% by weight
It is made by mixing an acrylic copolymer obtained by copolymerizing 82% by weight with cationic acidic colloidal silica, dispersing it in water, and crosslinking it within the particles.

[0033] The acrylic copolymer generally has a molecular weight of about 10 to
Amine number of about 100, preferably about 15 to about 80; 0 to
a hydroxyl value of about 200, preferably about 30 to about 130; and about 5,000 to about 100,000, preferably about 7;
It is desirable to have a number average molecular weight of from 0.000 to about 30,000.

Commercial products of cationic acidic colloidal silica include, for example, "Adelite CT-300" and "Adelite CT-400" (products of Asahi Denka Kogyo Co., Ltd.).
, "Snowtex O" (product of Nissan Chemical Industries, Ltd.),
"Cataroid SN" (produced by Catalysts Kasei Kogyo Co., Ltd.) is an aqueous dispersion containing SiO2 as a basic unit, and has an average particle size particularly within the range of 0.004 to 0.1 μm. things are included.

The mixing ratio of the acrylic copolymer and colloidal silica is not strictly limited, but generally, the solid content ratio is 1 to 50 parts by weight of colloidal silica per 100 parts by weight of the acrylic copolymer. It is preferably in the range of parts by weight, and more preferably in the range of 5 to 20 parts by weight.

In the aqueous dispersion of gelled fine particles containing colloidal silica produced in this manner, the average particle diameter of the dispersed particles is generally 1 μm or less, preferably 0.01 to 0.3 μm.
m, more preferably within the range of 0.05 to 0.2 μm. The particle size can be adjusted by adjusting the amount of cationic groups and the type and amount of colloidal silica in the acrylic copolymer, and a desired range can be easily obtained.

In the present invention, the method of making the curable resin composition aqueous with an aqueous dispersion of gelatinized fine particles involves neutralizing a solution of the curable resin composition in an organic solvent with an acidic compound, and dispersing the neutralized resin composition organically. After obtaining a solution, the gelled microparticle aqueous dispersion is gradually added to this solution until the phase transition from the oil phase to the aqueous phase occurs to obtain an aqueous dispersion. This can be carried out by adding an aqueous dispersion of fine particles. Examples of the acidic compound include hydrochloric acid, phosphoric acid, formic acid,
Inorganic and organic acids such as acetic acid, propionic acid, butyric acid, lactic acid, hydroxyacetic acid can be used. Neutralization is usually carried out until the final cationic electrodeposition coating has a pH of 3 to 9, preferably 5.
It is desirable to mix it so that it is in the range of ~8.

[0038] The organic solvent can be used without any particular restriction as long as it can dissolve or disperse the curable resin composition, but it is preferable to use a water-miscible organic solvent as the main component. Typical examples of water-miscible organic solvents include alcohols such as propanol, diacetone alcohol, sec-butanol, and tert-butanol, and ether alcohols such as ethylene glycol, butyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether, and diethylene glycol. Other examples include acetone and carbitol acetate. In addition to the above, organic solvents with poor water miscibility such as aromatic hydrocarbons such as xylene and toluene, esters such as butyl acetate, ketones such as methyl ethyl ketone, and alcohols such as n-butanol may also be used in combination. It can be used as

The amount of the gelled fine particle aqueous dispersion required for the above phase transformation varies depending on the type of curable resin, the type of neutralizer, the type of organic solvent, and the blending ratio of these. Although it is difficult to determine, it is usually desirable to blend the curable resin until the concentration of the curable resin is in the range of about 35 to 50% by weight of solids.

[0040] The solid content of the gelled fine particle aqueous dispersion is as follows:
It is desirable that the amount is about 20% by weight or less, preferably about 15% by weight or less, and more preferably about 10% by weight or less. If the solid content is higher than about 20% by weight, the particle size of the aqueous compound becomes large, which may lead to a decrease in paint storage stability, coated surface smoothness, etc., which is not preferable.

Further, as the gelled fine particle aqueous dispersion to be added to the water dispersion obtained by the above method, the same gelled fine particle aqueous dispersion as used to obtain the above water dispersion can be used. The solid content of the gelled fine particle aqueous dispersion is not particularly limited, and for example, about 10 to 40% by weight can be used.

In the present invention, the blending ratio of the aqueous dispersion of gelled fine particles is such that the total amount (solid content) of the gelled fine particles and the curable resin composition blended during and after water dispersion is such that the gelled fine particles are about 1-35% by weight, preferably about 4-2
A range of about 99-65%, preferably about 96-80% by weight of the curable resin composition is desirable. If the proportion of the gelled fine particles is less than about 1% by weight, the coatability of the coating film on the edge portion will decrease, while if it exceeds about 35% by weight, the smoothness of the coated surface will decrease, which is not preferable. In addition, the gelled fine particles are blended in a total amount (solid content) of the fine particles of about 40 to 80% by weight, preferably about 50 to 75% by weight at the time of water dispersion, and the remainder is added to about 60 to 20% by weight after water dispersion. weight%
, preferably about 50 to 25% by weight. The amount of gel particles added during water dispersion exceeds about 80% by weight, and the amount of gel particles added after water dispersion is about 2% by weight.
If it is less than 0% by weight, the storage stability of the paint and the anti-corrosion properties of the paint film on the edges will decrease, and conversely, if the amount of gelled fine particles added at the time of water dispersion is less than about 40% by weight, then the gelled particles added after water dispersion will be reduced. If the amount of fine particles exceeds about 60% by weight, it is not preferable because the smoothness of the coating film may deteriorate.

[0043] Aqueousization can be carried out using a conventionally known dispersing machine such as a dissolver or a homomixer without any particular restriction. Further, the electrodeposition coating composition of the present invention includes:
Although conventionally used coloring pigments, extender pigments, antirust pigments, etc. can be blended, it is preferable not to blend extender pigments in terms of coating surface smoothness.

[0044]

[Operation and Effects of the Invention] In the cationic electrodeposition paint obtained by the present invention, the gelled fine particles added are co-electrodeposited without causing problems such as agglomeration, abnormal electrodeposition, or sedimentation, and are formed into gelled fine particles during baking. The silanol groups generated by hydrolysis of the existing alkoxysilane groups condense with each other and hydroxyl groups, resulting in interparticle crosslinking and crosslinking with the base resin, and the volume effect of the gelled fine particles themselves. Since the decrease in the melt viscosity of the film can be controlled, the smoothness of the coating film and the film forming properties at the edge portions can be easily maintained.

Furthermore, in the present invention, when a gelled fine particle aqueous dispersion is used when dispersing the curable resin composition in water, the gelled fine particle component is water-dispersed in a form entangled with the curable resin composition, Since the gelling fine particle component itself has no fluidity and has good water dispersibility, it has the effect of providing a paint with excellent storage stability and film forming properties on the edge part. When an aqueous fine particle dispersion is added, gelled fine particles are present between the particles composed of the curable resin composition and gelled fine particles, which reduces the adhesion between the particles and lowers the melt viscosity of the system. It is presumed that the film formation properties on the edge portions are improved by the increase in .

Furthermore, in the present invention, the cationic electrodeposition coating film formed using the cationic electrodeposition coating composition obtained in the present invention can be further coated with the following intermediate coating composition.

[0047] By applying the intermediate coating material on the cationic electrodeposition coating film, it is possible to have the advantage that a coating film having superior coating surface smoothness can be obtained.

Examples of the intermediate coating paint include those described in JP-A No. 63-248871 filed by the present applicant. Specifically, (A) cyclohexanedimethanol and aliphatic It consists of a saturated dibasic acid, contains primary hydroxyl groups at both ends, and has a number average molecular weight of 300 to 8.
00 linear low molecular weight polyester diol, (B) consisting of polybasic acid and polyhydric alcohol with a number average molecular weight of 1.0
00 to 5,000 hydroxyl group-containing polyester resin and (C) an average degree of condensation of 2.5 or less, and 1.0 to 1.5 imino groups and 0.5 to 0.5 methylol groups per triazine nucleus. Based on the total solid weight of components (A), (B), and (C), the main component is a melamine resin in which 1.2 and the remainder are alkoxy groups, and component (A) is 10 to 30.
Weight%, component (C) is 25 to 40% by weight, the rest is (B)
This is an intermediate coating composition.

[0049] The above intermediate coating paint has the above (A), (B), (
Although component C) is the main component, various kinds of epoxy resins, leveling agents, anti-sag agents, curing accelerators (acid catalysts), modifiers, and auxiliary agents can be added as necessary.

[0050] In addition, inorganic pigments such as titanium oxide, barium sulfate, tantalum, and clay, as well as coloring agents, are used to improve the film thickness retention of the intermediate coating film, painting workability, and physical strength of the paint film. The above organic pigments (A), (B) and (
C) 50 parts by weight per 100 parts by weight of the total resin solid content of component
It is preferable to mix 100 parts by weight.

[0051] In the method of forming a coating film, first, the above-described cationic electrodeposition coating composition is diluted with deionized water or the like so that the solid content concentration is generally about 5 to 20% by weight, and then the pH is adjusted to 5.5%.
The electrodeposition bath is adjusted to a temperature of 5 to 9.0, preferably 5.8 to 7.0, the bath temperature is adjusted to 15 to 35°C, and the electrodeposition is carried out under the conditions of a load voltage of 50 to 400V. The uncured electrodeposition coating film is baked at a temperature of 100° C. to 200° C. to form an electrodeposition coating film having a dry film thickness of 10 to 40 μm. Next, the above-mentioned intermediate coating paint is adjusted to the appropriate viscosity using an organic solvent on top of this electrodeposition coating film, and is applied by spray coating, electrostatic coating, etc., and heated at a temperature of 120°C or higher to achieve a dry film thickness of 3.
An intermediate coating film of 0 to 45μ is formed.

[0052] The surface of the coating film thus obtained, consisting of the electrodeposition coating film to the intermediate coating film, has excellent smoothness and good edge coverage. Furthermore, even if a top coat is applied thereon, the coating film will be smooth and have excellent image clarity.

Furthermore, when excellent chipping resistance is required for the coating film to be formed, a barrier coat (mainly composed of a modified polyolefin resin having a specific static glass transition temperature) is applied on the electrodeposited coating film. JP-A-61-114779
No. 3, etc.) may be painted.

[0054]

EXAMPLES The present invention will be explained below based on examples. Note that both parts and % represent parts by weight and % by weight.

Curable resin composition varnish Epoxy resin having an epoxy equivalent weight of 500 (Epicote 1
001) 500 parts was dissolved in 300 parts of methyl isobutyl ketone, diethylamine was added dropwise at 80 to 100°C, and 1
The mixture was heated to 20°C and held for 1 hour to obtain an epoxy resin-amine adduct. Separately, 174 parts of tolylene diisocyanate was added dropwise to 180 parts of cellosolve at 60 to 80°C, heated to 120°C and held for 1 hour to obtain blocked isocyanate. The epoxy resin-amine adduct and blocked isocyanate were mixed to obtain a resin composition with a solid content of about 74%. Next, 1.5 parts of dibutyltin benzoate oxy and 5 parts of acetic acid were added to 135 parts of this mixture and mixed with a dissolver to obtain a curable resin composition varnish with a solid content of 72%.

Pigment paste 5 parts of the above epoxy resin-amine adduct, 19 parts of titanium oxide
parts, 5 parts of purified clay, 1 part of carbon black, 0.0 parts of acetic acid.
25 parts of deionized water and 39.7 parts of deionized water were dispersed in a pebble mill to obtain a pigment paste with a solid content of 43%.

Example 1 139 parts of the 72% curable resin composition varnish was mixed with a gelled fine particle dispersion having a solid content of 10% (Example 1 of JP-A-2-64169) while stirring with a dissolver. 100 parts of the gelled fine particle dispersion containing 20% cationic acidic colloidal silica obtained based on diluted to a solid content of 10%) were gradually added to give a solid content of 46%.
An aqueous dispersion of was obtained. Subsequently, the resulting aqueous dispersion had a solid content of 2
0% gelled fine particle dispersion (dispersion before dilution) 25
346 parts of deionized water and 70 parts of pigment paste were blended to obtain a cationic electrodeposition paint with a solid content of 20%.

Example 2 In Example 1, a gelled fine particle dispersion with a solid content of 10% (
Example 1 except that a dispersion of cationic electrodepositable gelling fine particles with a solid content of 20% obtained based on Example 1 of JP-A-2-47173 was diluted to a solid content of 10%). A cationic electrodeposition paint with a solid content of 20% was obtained in the same manner as above.

Example 3 In Example 1, a 10% gelled fine particle dispersion (Japanese Unexamined Patent Publication No. 2-6416) was used instead of the gelled fine particle dispersion having a solid content of 10%.
Example 1 except that a dispersion of gelled fine particles containing 20% cationic acidic colloidal silica obtained based on Example 1 of Publication No. 9 was diluted to 10% solid with deionized water). An electrodeposition paint with a solid content of 20% was obtained in the same manner. The storage stability and coating film performance of the cationic electrodeposition paints obtained in the above examples are summarized in Table 1.

Coating film formation method A 0.8 x 300 x 90 mm cold-rolled dull steel plate (end surface and (the angle with the flat part was 45 degrees) was immersed, and electrodeposition was performed using it as a cathode. The electrodeposition coating conditions were an electrodeposition paint bath temperature of 30°C, pH 6.5, and voltage of 300V to form an electrodeposition coating film with a film thickness (based on the dry film thickness) of 20 μm, and after electrodeposition, the coating film was washed with water. Then, baking was performed at 170°C for 20 minutes.

Example 4 An intermediate coating based on Example 1 of JP-A No. 63-248871 was applied to the electrodeposited coating film of a painted plate prepared using the cationic electrodeposition coating of Example 1 using Ford Cup #. 4/20℃
diluted with xylene for 25 ± 1 seconds, and the dry film thickness was 40
Paint to ~45μ and leave at room temperature for 7 minutes, 140℃
Bake to harden for 30 minutes. Then, a top coat (manufactured by Kansai Paint Co., Ltd., Amylac White amino alkyd resin top coat, 1 coat, 1 bake white paint, pencil hardness H) was applied to a dry film thickness of 30 to 40μ, and
Baking drying was performed at 0° C. for 30 minutes.

Intermediate coating: (i) Made of cyclohexanedimethanol and a mixture of dibasic acid diesters of succinic acid, glutaric acid, and adipic acid, it is a polyester diol (number average molecular weight 435, hydroxyl group) having primary hydroxyl groups at both ends. price 230) 20 copies (
ii) 274 parts of trimethylolpropane, 944 parts of 1,6 hexanediol, 462 parts of hexahydrophthalic anhydride
45 parts of polyester varnish having an acid value of 10, a number average molecular weight of 1,550, and a hydroxyl value of 108, consisting of 876 parts of adipic acid and 876 parts of adipic acid (iii) Cymel 327 (manufactured by American Cyanamid Company, trade name), average degree of condensation of 1.
8. 35 parts of melamine resin having 1.5 imino groups, 0.7 methylol groups and 3 methoxy groups per triazine nucleus and (iv) 90.3 parts of pigment (70 parts of titanium oxide, 20 parts of barium sulfate) 70.3 parts of carbon black).

Example 5 An intermediate coating (“Amilac N-2 Sealer” aminopolyester resin intermediate coating manufactured by Kansai Paint Co., Ltd.) was applied to the electrodeposited coating film obtained in Example 1 to a dry film thickness. 25-35
μ was coated, baked and dried at 140° C. for 30 minutes, and then the top coat used in Example 4 was applied thereon in the same manner. The results are summarized in Table-1.

Comparative Example 441 parts of deionized water was gradually added to 139 parts of the 72% curable resin composition varnish while stirring with a dissolver, and then 70 parts of the pigment paste was blended to give a solid content of 20%. An aqueous dispersion of was obtained. Next, the water dispersion 650
75 parts of the gelled fine particle dispersion containing 20% cationic acidic colloidal silica used in Example 3 were mixed with this part using a resolver to obtain a cationic electrodeposition paint having a solid content of 20%. The results are shown in Table-1.

[0065] In addition, Examples 1 to 3 and Comparative Examples were manufactured in the same manner as described in Examples 1 to 3 and Comparative Examples except that no pigment paste was blended, and Examples containing no pigment components were prepared. Aqueous dispersions of Examples 1 to 3 and Comparative Examples were obtained. Each of these aqueous dispersions in Example 1 had an average particle size of 0.
．． Example 2 has an average particle size of 0.2 μ or less and has good storage stability, and Example 3 has an average particle size of 0.2 μ or more and has good storage stability. In the comparative example, the average particle size was 0.5μ or more, and storage-stable sediments and aggregates were observed. Storage stability was determined by observing sediments and aggregates after standing at 30°C for 7 days.

[0066]

[Table 1]

Performance test method (*1) Coating film melt viscosity The melt viscosity of the electrodeposited coating film during baking was measured using the rolling ball viscosity measurement method (JIS
- Z-0237) was evaluated based on the thermal fluid appearance of the scratch marks. The numerical value indicates the lowest viscosity (centipoise).

(*2) Under the condition that the cured film thickness of the flat part of the end face coating is 20 μm, use a cutter knife's replaceable blade (Olfa LB) with an edge angle of about 20°.
-10 ~ Pearl Bond #3020 treatment) by electrodeposition coating,
A test plate is created by curing under specified baking conditions. Set the test plate in a salt spray device so that the edge part is vertical, and use the JIS Z2371 salt spray test to obtain 168.
Evaluate the corrosion resistance of the edge portion after a period of time.

○: No rust at all △: Rust occurs ×: Significant rust occurs.

(*3) Painted surface smoothness Visually evaluate the finish of the electrodeposited surface. ○ Good △ Slightly poor × Defective.

(*4) Impact resistance Testing is conducted in an atmosphere at 20° C. according to JIS K5400-1979 6,13,3B method. weight 50
0g and the point of impact with a diameter of 1/2 inch, it indicates the maximum height without causing damage to the paint film (cm). The maximum value was 50 cm.

(*5) Chipping resistance The baked electrodeposition coated plate was further coated with a thermosetting intermediate coating and top coating, and the following tests were conducted on the cured product.

■Test equipment: Q-G-R gravelometer (product of Q Panel Company) ■Stone to be sprayed: Crushed stone with a diameter of approximately 15 to 20 mm■
Capacity of stone to be sprayed: Approximately 500ml■ Blowing air pressure: Approximately 4kg/cm2 ■Temperature during test:
Approximately 20℃ Attach the test piece to a test piece holding stand and apply a weight of approximately 4kg/cm2.
Approximately 500 ml of crushed stone was ejected onto the test piece at a blowing air pressure of 100 ml, and the coated surface condition and salt water spray resistance were evaluated. The condition of the painted surface is visually observed and evaluated using the following criteria. (Evaluation) ○ (Good): Only a few scratches due to impact were observed in a part of the top coat, and no peeling of the electrodeposition coating was observed. Δ (slightly poor): Scratches caused by impact were observed on the top coat and intermediate coat, and slight peeling of the electrodeposited coating was observed. × (Poor): Many scratches due to impact were observed in the top coat and intermediate coat, and also considerable peeling of the electrodeposited coating was observed.

(*6) Secondary adhesion after immersion in hot water JIS K5400-1979 after immersion in water at 40°C for 20 days
6.15, make gongs on the coating film, apply adhesive cellophane tape to the surface, and evaluate the coated surface after abruptly peeling it off. ○: Good with no abnormalities. △: Edges of goban are slightly peeled. ×: A part of the goblin is peeled off.

(*7) Cross-cut scratches are made on the electrodeposited coating with a knife to reach the salt water spray resistant substrate, and this is
Perform a time salt spray test and measure the extent of rust and blisters from knife scratches.

(*8) 35 μm of amino alkyd resin paint Amirac Clear (manufactured by Kansai Paint Co., Ltd.) was further applied onto the 2-coat weather-resistant baked electrodeposition coated plate and baked at 140° C. for 15 minutes. This coated plate was subjected to a Sunshine Weather-Ometer for 20 hours, and after being immersed in water at 40° C. for 20 hours, a cross cut was made on the coated plate and a peel test was performed using cellophane adhesive tape. Repeat this test.

(*9) Image clarity measuring device [IMAGE C
LARITY METER: Measured using Suga Test Instruments Co., Ltd. The numbers in the table are ICM values that range from 0 to 100%.
A CM value of 80 or more indicates extremely excellent image clarity.

(*10) Goban eyes (1×1mm 10
0 pieces) Cellophane adhesive tape test. Shows the number of squares remaining.

[0079]

Claims (1)

[Claims] Claim 1: A curable resin organic solution prepared by dissolving or dispersing a cationic resin and a blocked polyisocyanate compound in an organic solvent is made aqueous with an aqueous dispersion of a cationic electrodepositable gelling fine particle polymer to obtain an aqueous dispersion. . A method for producing a cationic electrodeposition paint, further comprising adding the aqueous dispersion of the cationic electrodepositable gelling fine particle polymer to the aqueous dispersion.