Patent Description:
Cationic electrodeposition coating compositions have excellent application workability and form coating films with superior corrosion resistance. They have thus been widely used for, for example, automobile parts, electrical equipment parts, and other industrial machinery, which are required to have such properties.

In general, cationic electrodeposition coating compositions are provided in the form of a mixture of two components, i.e., a resin emulsion component in which resin components comprising a cationic resin (e.g., an amino group-containing epoxy resin) and a curing agent (also called "crosslinking agent"; e.g., a blocked polyisocyanate compound) are mixed and dispersed in an aqueous medium, and a pigment dispersion paste component containing a pigment dispersed with a resin for pigment dispersion. Such a coating composition is used as a coating bath, and a current is applied using a substrate as a cathode and the counter electrode as anode to form a deposited coating film on the substrate. The deposited coating film is heated to form a crosslink-cured coating film.

The aforementioned heating during coating is usually performed at a temperature higher than <NUM>, but to reduce energy costs, it is becoming desired for the heating to be performed at a low temperature (<NUM> to <NUM>, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>). This is called "low-temperature baking".

The low-temperature baking is commonly performed using a low-temperature curable blocked polyisocyanate compound as a curing agent. For example, Patent Document <NUM> discloses that low-temperature curing is performed using an oxime-blocked isocyanate-containing cationic electrodeposition coating composition. Patent Document <NUM> discloses a low-temperature-baking electrodeposition coating composition that is baked at a temperature of <NUM> to <NUM> and that oxime-blocked and lactam-blocked polyisocyanate compounds can dissociate (reaction) at relatively low temperature. Patent Document <NUM> discloses that a self-crosslinking resin containing a specific blocked isocyanate group can be cured at a low temperature of <NUM> or less and can also be used as a cationic electrodeposition coating composition.

Furthermore, Patent Document <NUM> discloses a method for forming a coating film by low-temperature baking, comprising performing electrodeposition coating using a base resin (an amine-added epoxy resin), performing electrodeposition coating using an aqueous dispersion of a blocked polyisocyanate curing agent to which water dispersibility is imparted, and drying the resulting coating film by heating at <NUM> to <NUM>.

Patent Document <NUM> and Patent Document <NUM> disclose aqueous cathodic electrodeposition coating compositions comprising Michael addition reaction donor and acceptor components.

However, there are cases in which the long-term storage stability (bath stability) is insufficient in the electrodeposition coating composition with a high reactivity at low temperatures as described in Patent Documents <NUM> to <NUM> above, resulting in, for example, poor finished appearance and corrosion resistance of the coating film. In addition, in the coating method described in Patent Document <NUM> above, since coating compositions and coating are separately used for the base resin and the curing agent, the storage stability (bath stability) of the coating compositions is improved. However, the curing agent may not be homogeneously present in the coating film, resulting in, for example, poor corrosion resistance. Further, since this method requires additional coating and washing steps, existing equipment cannot be used, and it is necessary to provide additional equipment.

The present disclosure has been developed in view of the foregoing circumstances. The present disclosure provides a cationic electrodeposition coating composition which is superior in storage stability, low-temperature curability and finished appearance.

The present inventors conducted extensive research to achieve a cationic electrodeposition coating composition which is superior in storage stability, low-temperature curability and finished appearance, and found that such a cationic electrodeposition coating composition can be achieved by cationic electrodeposition coating compositions containing emulsion particles (A) containing a Michael addition reaction donor component, emulsion particles (B) containing a Michael addition reaction accepter component and a Michael addition reaction catalyst (C), wherein the Michael addition reaction catalyst (C) is included in the emulsion particles (A) or the emulsion particles (B), or included in the cationic electrodeposition coating composition by being microencapsulated. The present invention has been thus accomplished.

In other words, the cationic electrodeposition coating composition and the method for electrodeposition coating of the present disclosure have the constitutions as defined in the appended claims.

The cationic electrolytic coating composition of the present disclosure is superior in curability, finished appearance, and corrosion resistance, even if cured at an ordinary temperature or a low temperature, while ensuring good coating stability (bath stability).

Specifically, automobile bodies coated with the cationic electrodeposition coating compositions of the present disclosure have superior coating finished appearance and less corrosion or deterioration, even when the car is driven for a long period of time in an environment which snow-melting salts have been spread. Moreover, the cationic electrodeposition coating compositions of the present disclosure also have superior storage stability over a long period of time.

A cationic electrodeposition coating composition comprises emulsion particles (A) containing a Michael addition reaction donor component, emulsion particles (B) containing a Michael addition reaction acceptor component, and a Michael addition reaction catalyst (C) wherein the Michael addition reaction catalyst (C) is contained in the emulsion particles (A) or the emulsion particles (B) or is contained in the cationic electrodeposition coating composition by being microencapsulated.

The cationic electrolytic coating composition is a coating composition that is curable at low temperatures, primarily by the Michael addition reaction. The Michael addition reaction is not intended to be limited by any particular theories, and is taught, for example, in <NPL>. This reaction is believed to occur between the Michael donor and Michael acceptor components in the presence of a catalyst.

The cationic electrodeposition coating composition of the present disclosure can improve storage stability (bath stability) since the emulsion particle (A) as a donor component of the Michael addition reaction, and emulsion particle (B) as an acceptor component of the Michael addition reaction are present separately in the coating composition (in an aqueous solvent). In particular, the cationic electrodeposition coating is effective for the storage stability of one-component type low-temperature baking coating (or one-component type room-temperature baking coating) that undergoes the curing reaction at <NUM> to <NUM> (preferably at <NUM> to <NUM>, more preferably at <NUM> to <NUM>).

In the present disclosure, "aqueous solvent" means a solvent whose main component is at least one of water and a hydrophilic solvent. Examples of hydrophilic solvents include ethylene glycol, ethylene glycol monoalkyl ether (e.g., methyl ether, ethyl ether, butyl ether, etc.), diethylene glycol, diethylene glycol monoalkyl ether (e.g., methyl ether, ethyl ether, butyl ether, etc.), glyme-based solvents (e.g., ethylene glycol dimethyl ether, etc.), diglyme-based solvents (e.g., diethylene glycol dimethyl ether, etc.), alcohol-based solvents (e.g., methyl alcohol, ethyl alcohol, propyl alcohol, n-butyl alcohol, etc.), propylene glycol, propylene glycol monoalkyl ether (e.g., methyl ether, ethyl ether, butyl ether, etc.), dipropylene glycol, dipropylene glycol monoalkyl ether (e.g., methyl ether, ethyl ether, butyl ether, etc.), These hydrophilic solvents may be used alone or in combinations of more than two species.

In the present disclosure, "compound" is a generic name including monomers, oligomers, polymers (resins), etc..

In the present disclosure, "emulsion particle" is a particle in which a compound is dispersed in a solvent, and causes turbidity rather than transparency.

The present disclosure will be described in detail below.

The emulsion particle (A) containing Michel addition reaction donor component is an emulsion particle containing at least one of active hydrogen group-containing compound (A-<NUM>) selected from the group consisting of an active methylene group-containing compound, a primary and/or secondary amine group-containing compound, a thiol group (mercapto group) containing compound, and a hydrogen group-containing compound. Among these, the active hydrogen group-containing compound (A-<NUM>) is preferably at least one of the active methylene group-containing compound and the primary and/or secondary amino group-containing compound.

The active hydrogen group-containing compound (A-<NUM>) is not specifically limited. For example, active methylene group-containing compounds such as methyl acetoacetate, ethyl acetoacetate, t-butyl acetoacetate, <NUM>-ethylhexyl acetoacetate, lauryl acetoacetate, acetoacetanilide, <NUM>-acetoacetoxyethyl methacrylate, allyl acetoacetate, butanediol diacetoacetate, <NUM>,<NUM>-hexanediol diacetoacetate, neopentyl glycol diacetoacetate, cyclohexanedimethanol diacetoacetate, ethoxylated bisphenol A diacetoacetate, trimethylolpropan triacetoacetate, glycine triacetoacetate, polycaprolactone triacetoacetate, pentaerythritol tetraacetoacetate and the like; primary and/or secondary amino group-containing compounds such as ethylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine tetrapropylenepentamine and the like; thiol group (mercapto group) containing compounds such as pentaerythritol tetrakis (<NUM>-mercaptopropionate), trimethylolpropane tris (<NUM>-mercaptopropionate), tris-[(<NUM>-mercaptopropionyloxy) -ethyl] - isocyanurate, tetraethylene glycol bis (<NUM>-mercaptopropionate), dipentaerythritol hexakis (<NUM>-mercaptopropionate), pentaerythritol tetrakis (<NUM>-mercaptobutyrate), trimethylolpropane tris (<NUM>-mercaptobutyrate) and the like; hydroxy group-containing compounds such as alkanediol, poly (oxyalkylene) glycol, glycerol, diglycerol, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, and the like; or reaction products of these may be employed as the active hydrogen group-containing compound (A-<NUM>). These may be used alone or in combinations of more than two species.

As the active hydrogen group-containing compound (A-<NUM>) described above, a compound whose skeleton is a resin can also be favorably used. Specific examples include (Example <NUM>) to (Example <NUM>) below.

The epoxy resin used for the formation of the active hydrogen group-containing epoxy resin described above (Example <NUM>) is a resin having at least one epoxy group, preferably two or more, in one molecule, as well as having a number average molecular weight of at least <NUM>, preferably <NUM> to <NUM>,<NUM>, more preferably <NUM> to <NUM>,<NUM>, and an epoxy equivalent of at least <NUM>, preferably <NUM> to <NUM>,<NUM>, and more preferably <NUM> to <NUM>,<NUM>. As such an epoxy resin, for example, that resulting from the reaction of a polyphenolic compound with epihalohydrin (e.g., epichlorohydrin, etc.) can be used.

The polyphenolic compound includes, for example, bis(<NUM>-hydroxyphenyl)-<NUM>,<NUM>-propane [bisphenol A], bis (<NUM>-hydroxyphenyl) methane [bisphenol F], bis (<NUM>-hydroxycyclohexyl) methane [hydrogenated bisphenol F], <NUM>,<NUM>-bis (<NUM>-hydroxycyclohexyl) propane [hydrogenated bisphenol A], <NUM>,<NUM>'-dihydroxybenzophenone, bis (<NUM>-hydroxyphenyl) -<NUM>,<NUM>-ethane, bis (<NUM>-hydroxyphenyl) -<NUM>,<NUM>-isobutane, bis (<NUM>-hydroxy-<NUM>-tert-butyl-phenyl) -<NUM>,<NUM>-propane, bis (<NUM>-hydroxynaphthyl) methane, tetra (<NUM>-hydroxyphenyl) -<NUM>,<NUM>,<NUM>,<NUM>-ethane, <NUM>,<NUM>'-dihydroxydiphenyl sulfone, phenol novolac, and cresol novolac.

In addition, the epoxy resin obtained by a reaction between a polyphenol compound and epihalohydrin is preferably a resin represented by the following formula which is derived from bisphenol A. <CHM>
Here, <NUM> to <NUM> is a preferable range for n.

Examples of commercially available products of the epoxy resin include products sold under the trade names of jER828EL, jER1002, jER1004, and jER1007 by Mitsubishi Chemical Corporation.

In addition, as the above active hydrogen group-containing epoxy resin, an epoxy resin containing polyalkylene oxide chains in the resin skeleton can be used. Generally, such epoxy resins can be obtained by reacting an epoxy resin having at least one (α) epoxy group, preferably two or more, with an alkylene oxide or a polyalkylene oxide to introduce a polyalkylene oxide chain, or (β) reacting a polyphenolic compound with a polyalkylene oxide having at least one, preferably two or more epoxy groups to introduce a polyalkylene oxide chain. Alternatively, epoxy resins already containing polyalkylene oxide chains may be used. (See, for example, <CIT>).

The alkylene group in the polyalkylene oxide chain is preferably C<NUM> - <NUM> alkylene, more preferably an ethylene group, a propylene group, or a butylene group, and particularly preferably a propylene group.

As the epoxy resin other than the bisphenol type epoxy resin, t-butylcatechol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin can also be suitably used, and one or two or more species of these can be used alone or in combination. Commercial products of novolac type epoxy resins include, for example, the DEN-<NUM> of phenol novolac resins manufactured by Dow Chemical Co. , and the YDCN-<NUM> of cresol novolac resins manufactured by Toto Kasei Co.

In addition, as the active hydrogen group-containing epoxy resin described above, those having at least one of primary amino groups, secondary amino groups, and tertiary amino groups are preferable from the viewpoint of coating properties of the cationic electrodeposition coating. Here, in the case of primary and/or secondary amino groups, an effect as a donor component of the Michael addition reaction can be exhibited in addition to improved coating properties.

Examples of the amino group addition compound include, for example, (<NUM>) adducts of an epoxy resin with primary mono- and polyamines, secondary mono- and polyamines, or primary and secondary mixed polyamines (see, for example, <CIT>); (<NUM>) adducts of epoxy resins with secondary mono- and polyamines having ketiminated primary amino groups (see, for example, <CIT>); and (<NUM>) reaction products obtained by etherifying epoxy resins with hydroxy compound having ketiminated primary amino groups (see, for example, <CIT>) and the like.

Examples of the primary mono-and polyamines secondary mono-and polyamines or primary and secondary mixed polyamines which are used in the manufacture of the amino group-containing epoxy resins as described above in (<NUM>) include mono- or di-alkylamines such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, monobutylamine, and dibutylamine; alkanolamines such as monoethanolamine, diethanolamine, mono(<NUM>-hydroxypropyl)amine, and monomethylaminoethanol; alkylene polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, and triethylenetetramine; and the like.

Examples of the secondary mono- and polyamines containing a ketiminated primary amino group used for the manufacture of the amino group-containing epoxy resin described above in (<NUM>) include ketiminated products obtained by reacting a ketone compound with, for example, diethylenetriamine, among the primary and secondary mixed polyamines described above in (<NUM>) as materials used for producing the amine-added epoxy resin.

Examples of the ketiminated primary amino group-containing hydroxy compound described above in (<NUM>) as a material used for producing the amino group-containing epoxy resin include hydroxy group-containing ketiminated products obtained by reacting a ketone compound with a primary amino group- and hydroxy-containing compound, for example, monoethanolamine or mono(<NUM>-hydroxypropyl)amine, among the primary mono- and polyamines, secondary mono- and polyamines, and primary and secondary mixed polyamines as materials used for producing the amino group-containing epoxy resin described above in (<NUM>).

In addition, an active hydrogen group other than the aforementioned amino group can be added.

The active hydrogen group-containing compound is not limited as long as it has a reactive functional group (e.g., a carboxyl group, a primary amino group or a secondary amino group) which is capable of reacting with an epoxy group other than the active hydrogen group as a donor component, and specifically include an active methylene group-containing compound such as malonic acid, alkyl malonate, acetoacetic acid, isobutyrylacetic acid, benzoyl acetic acid, propionyl acetic acid; thiol group-containing compounds such as thioglycolic acid, thiomalic acid, thiosalicylic acid, dithiosalicylic acid, mercaptopropionic acid, <NUM>-mercaptobutyric acid; hydroxy group-containing compounds such as lactic acid, glycolic acid, dimethylolpropionic acid, hydroxybutyric acid, glyceric acid, dimethylolbutanoic acid, salicylic acid, mandelic acid, ε-caprolactone, monoethanolamine; and the like. These active hydrogen group-containing compounds may be used alone or in combinations of two or more species.

The above active hydrogen group-containing epoxy resins can be modified by modifiers, if necessary. Such modifiers are not particularly limited as long as having reactivity with epoxy resins, and include, for example, polyamide amines, polycarboxylic acids, fatty acids, polyisocyanate compounds, polyisocyanate compounds, acrylic monomers, acrylic monomer polymerized compounds, xylene formaldehyde compounds, and epoxy compounds. These modifiers can be used alone or in combination of two or more.

The addition of the aforementioned amine compounds, the active hydrogen group-containing compounds, or the modifiers to epoxy resins can usually be carried out in a suitable solvent at a temperature of about <NUM> to about <NUM>, preferably about <NUM> to about <NUM> for about <NUM> to <NUM> hours, preferably about <NUM> to <NUM> hours.

The reaction solvents described above include, for example, hydrocarbons such as toluene, xylene, cyclohexane, n-hexane; esters such as methyl acetate, ethyl acetate, and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone; amides such as dimethylformamide, dimethylacetamide; alcohols such as methanol, ethanol, n-propanol and iso-propanol; ether alcohol compounds such as ethyleneglycol monobutyl ether and diethylene glycol monoethyl ether; or mixtures thereof.

It is generally preferable for the number average molecular weight of the active hydrogen group-containing epoxy resin to be within the range of <NUM>,<NUM> to <NUM>,<NUM> from the viewpoints of finished appearance, corrosion resistance, etc., further within the range of <NUM>,<NUM> to <NUM>,<NUM>, and more particularly within the range of <NUM>,<NUM> to <NUM>,<NUM>.

The amine value of the active hydrogen group-containing epoxy resin is generally more than <NUM> KOH/g, preferably within the range of <NUM> to <NUM> KOH/g, and more preferably within the range of <NUM> to <NUM> KOH/g, based on the resin solids content.

The amine value in the present specification is measured according to the JIS K <NUM>-<NUM> standard. All of the amine values are those per resin solids (mg KOH/g).

In the present specification, the number-average molecular weight and the weight-average molecular weight are calculated by converting the retention time (retention volume) measured using gel permeation chromatography (GPC) to the molecular weight of polystyrene using the retention time (retention volume) of a standard polystyrene with a known molecular weight measured under the same conditions. Specifically, using "HLC8120GPC" (trade name, manufactured by Tosoh) as a gel permeation chromatography apparatus, and using four columns of "TSKgel G-4000HXL," "TSKgel G-3000HXL," "TSKgel G-2500HXL," and "TSKgel G-2000HXL" (trade names, all manufactured by Tosoh) as columns, it is possible to measure under the conditions of mobile phase tetrahydrofuran, a measurement temperature of <NUM>, a flow rate of <NUM>/min, and a detector RI.

A dispersion method of the active hydrogen group-containing epoxy resin obtained in this manner in the aqueous solvent is not particularly limited, and a known method can be used per se. However, it is preferable to neutralize the active hydrogen group-containing epoxy resin solution with acid compounds and disperse it.

Known acid compounds can be used as the acid compounds without particular limitation, and specific examples include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, sulfamic acid; organic acids including carboxylic acid compounds such as formic acid, acetic acid, propionic acid, lactic acid, and the like. These acid compounds can be used alone or in combinations of two or more. Among these acid compounds, organic acids can be preferably used, and carboxylic acid compounds can be more preferably used.

Alternatively, an emulsifier can be used as an alternative method of dispersion. The emulsifier described above can be used without particular limitation, and include, for example, nonionic emulsifiers, cationic emulsifiers, or anionic emulsifiers, which can be used alone or in combinations of two or more. Among these emulsifiers, nonionic emulsifiers and/or cationic emulsifiers are preferred, and cationic emulsifiers are more preferred.

The emulsion particle (B) containing the Michael Addition Reaction acceptor component is an emulsion particle containing a compound (B-<NUM>) having at least one α,β-unsaturated carbonyl group selected from the group consisting of (meth)acryloyloxy group-containing compounds, (meth)acrylamide group-containing compounds, maleic acid-based compounds, fumaric acid-based compounds, and itaconic acid-based compounds.

The compound (B-<NUM>) having the α,β-unsaturated carbonyl group is not particularly limited as long as it contains more than one acceptor component (α,β-unsaturated carbonyl group) per molecule, and the (meth)acryloyloxy group-containing compounds include a diacrylate such as ethylene glycol diacrylate, propylene glycol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, tetrapropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, ethoxylated bisphenol A diacrylate, bisphenol A diglycidyl ether diacrylate, resorcinol diglycidyl ether diacrylate, <NUM>,<NUM>-propanediol diacrylate, <NUM>,<NUM>-butanediol diacrylate, <NUM>,<NUM>-pentanediol diacrylate, <NUM>,<NUM>-hexanediol diacrylate, neopentylglycol diacrylate, cyclohexanedimethanol diacrylate, ethoxylated neopentylglycol diacrylate, propoxylated neopentylglycol diacrylate, ethoxylated cyclohexanedimethanol diacrylate, propoxylated cyclohexanedimethanol diacrylate, acrylated epoxydiacrylate, allyluretane diacrylate, aliphatic uretane diacrylate, polyester diacrylate; a triacrylate such as trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tris(<NUM>-hydroxyethyl) isocyanurate triacrylate, ethoxylated glycerol triacylate, propoxylated glycerol triacrylate, pentaerythritol triacrylate, allyl urethane triacrylate, aliphatic urethane triacrylate, melamine triacrylate, aliphatic epoxy triacrylate, epoxy novolac triacrylate, and polyester triacrylate; a tetra acrylate such as di-trimethylol propane tetraacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, ethoxylated dipentaerythritol tetraacrylate, propoxylated dipentaerythritol tetra acrylate, allylurethane tetraacrylate, aliphatic urethane tetraacrylate, melamine tetraacrylate, epoxynovolac tetraacrylate; pentaacrylate such as dipentaerythritol pentaacrylate, melamine pentaacrylate, and the like. These compounds may be used alone or in combinations of two or more species.

As the α,β-unsaturated carbonyl group containing compound (B-<NUM>) described above, it is also suitable to use a compound whose skeleton is a resin. Examples of manufacturing methods of the compound (B-<NUM>) include synthesizing of polyester resins, acrylic resins, epoxy resins, etc., and (<NUM>) the reaction of glycidyl (meth) acrylates with the carboxyl group of the resins, (<NUM>) the reaction of isocyanate ethyl (meth) acrylates with the hydroxy group of the resins, or (<NUM>) the reaction of (meth) acrylates, maleates, fumarates, itaconates, etc. with the epoxy group of the resins, and the like.

Polyester resins obtained by polycondensation reactions between polyvalent carboxylic acids including (anhydride) maleic acid, fumaric acid, itaconic acid, etc. and polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, tetramethylene glycol, <NUM>,<NUM>-hexanediol, neopentyl glycol, trimethylol propane, glycerin, pentaerythritol, and polyamide resins obtained by polycondensation reactions using polyhydric amines instead of the aforementioned polyhydric alcohols can also be used. Other examples include urethane compounds obtained by reacting polyfunctional polyisocyanate compounds with compounds having hydroxy and acryloyl groups (e.g., <NUM>-hydroxyethyl acrylate, <NUM>-hydroxybutyl methacrylate, etc.).

Among these, the α,β-unsaturated carbonyl group-containing epoxy resin and/or the α,β-unsaturated carbonyl group-containing acrylic resin are preferred, and α,β-unsaturated carbonyl group-containing epoxy resin is more preferred.

As the α,β-unsaturated carbonyl group containing epoxy resin described above, the epoxy resin described previously as the epoxy resin used for the formation of the active hydrogen group containing epoxy resin described above can be used as a raw material. It is preferable to add a tertiary amino group from the viewpoint of the coating property of cationic electrodeposition coating to the epoxy resin. (It is preferable for the α,β-unsaturated carbonyl group containing epoxy resin to not contain primary and secondary amino groups that have an effect as a donor component.

In addition, the α,β-unsaturated carbonyl group-containing epoxy resin may be modified by a modifier similar to the active hydrogen group-containing epoxy resin.

It is generally preferable for the number average molecular weight of the α,β-unsaturated carbonyl group-containing epoxy resin to be within the range of <NUM>,<NUM> to <NUM>,<NUM> from the viewpoints of finished appearance, corrosion resistance, etc., more preferably within the range of <NUM>,<NUM> to <NUM>,<NUM>, and particularly preferably within the range of <NUM>,<NUM> to <NUM>,<NUM>.

The amine value of the α,β-unsaturated carbonyl group-containing epoxy resin is generally <NUM> KOH/g or more based on the resin solids content, preferably within the range of <NUM> to <NUM> KOH/g, and more preferably within the range of <NUM> to <NUM> KOH/g.

The method for dispersing the α,β-unsaturated carbonyl group-containing epoxy resin obtained as described above in an aqueous solvent is not particularly limited, and a known method can be used. However, it is preferable to neutralize the α,β-unsaturated carbonyl group-containing epoxy resin solution with an acid compound and disperse it in water.

As the acid compound, known acid compounds can be used without particular limitation, and specific examples include, for example, inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, sulfamic acid; organic acids including carboxylic acid compounds such as formic acid, acetic acid, propionic acid, lactic acid, and the like. These acid compounds can be used alone or in combinations of two or more species. Among these acid compounds, organic acids can be preferably used, and particularly, the carboxylic acid compounds can be more preferably used.

Alternatively, an emulsifier can be used as an alternative method of dispersion. The emulsifiers described above can be used without particular limitation and include, for example, nonionic emulsifiers, cationic emulsifiers, or anionic emulsifiers, which can be used alone or in combinations of two or more. Among these emulsifiers, nonionic emulsifiers and/or cationic emulsifiers are preferred, and cationic emulsifiers are more preferred.

The Michael addition reaction catalyst (C) contained in the cationic electrodeposition coating composition of the present disclosure is included in either the emulsion particle (A) or the emulsion particle (B) described above, or microencapsulated in the cationic electrodeposition coating composition.

As the Michael addition catalyst (C), known catalysts for Michael addition reaction can be used without particular limitation, and at least one compound selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, quaternary ammonium compounds, tertiary amine compounds, guanidine compounds, amidine compounds, tertiary phosphine compounds, phosphazene compounds, tertiary sulfonium compounds, quaternary phosphonium compounds, and imidazole compounds can be preferably used. These compounds may be used alone or in combinations of two or more species. Among these compounds, a basic catalyst is preferred from the viewpoint of catalytic performance.

The amidine compounds described above can be used without particular limitation and include, for example, <NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-nonene-<NUM>(DBN), <NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-decen-<NUM>, <NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-undecene-<NUM>(DBU), <NUM>-hydroxypropyl-<NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-undecene-<NUM>, <NUM>-dibutylamino-<NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-undecene-<NUM> and the like.

The guanidine compounds described above can be used without particular limitation and include, for example, <NUM>,<NUM>-diphenylguanidine, <NUM>,<NUM>-dimethylguanidine, <NUM>,<NUM>,<NUM>,<NUM>-tetramethylguanidine (TMG). These catalysts can be used alone or in combinations of two or more species.

As the Michael addition reaction catalyst (C), the acid dissociation constant (pKa) of the basic catalyst is preferably <NUM> or more, more preferably <NUM> or more, particularly from the viewpoint of catalytic performance.

The basic catalyst is preferably a compound with a molecular weight of <NUM> or more, more preferably a molecular weight of <NUM> or more, and further preferably a molecular weight of <NUM> or more from the viewpoints of the finished appearance of the coating and water resistance of the coating.

The methods of increasing the molecular weight of the basic catalyst include for example, in the case of the amidine catalyst or the guanidine catalyst described above, (<NUM>) reacting the primary or secondary amino groups of the amidine catalyst or the guanidine catalyst above described with a compound containing a reactive functional group such as an epoxy or an isocyanate group, and (<NUM>) reacting the amidine catalyst or the guanidine catalyst above described with a carbodiimide compound, and both of these methods can be favorably used.

The blending quantity of the Michael addition catalyst (C) in the cationic electrodeposition coating composition is preferably within the range of <NUM> to <NUM>% by mass and more preferably within the range of <NUM> to <NUM>% by mass, based on the resin solids.

In the case that the Michael addition reaction catalyst (C) is contained in either the emulsion particle (A) containing the Michael addition reaction donor component or the emulsion particle (B) containing the Michael addition reaction acceptor component, it is preferred that the Michael addition reaction catalyst (C) is contained in the emulsion particle (B) containing the Michael addition reaction acceptor component from the viewpoint of the stability of the coating. Without wishing to be bound by any particular theory, it is believed that the Michael addition reaction starts when the catalyst (C) extracts hydrogen ions from the donor component.

Methods for causing the Michael addition reaction catalyst (C) to be included in the emulsion particle (B) include, for example, a method of homogeneously mixing the catalyst (C) with a component that contains the α,β-unsaturated carbonyl group containing compound (B-<NUM>), and then admixing with water to emulsify by phase change. In this case, emulsifiers can be used as needed.

In the case that the Michael addition reaction catalyst is microencapsulated in the cationic electrodeposition coating composition, it may be present in either the emulsion particle (A), in the emulsion particle (B), or in the solvent, since the catalyst is less likely to come into contact with other components.

Also, the microencapsulated catalyst is preferably a temperature-sensitive microencapsulated catalyst (C-<NUM>), since it is preferable for the encapsulated catalyst to be eluted by heat and diffused into the uncured coating after coating, and then for the Michael addition reaction to begin.

As used herein, temperature sensitivity means a property of the catalyst changes with changes in temperature. Specifically, the temperature-sensitive microencapsulated catalyst is one in which the state of the microcapsule changes when the temperature exceeds a certain temperature and the catalyst inside elutes.

The elution temperature is preferably between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, and further preferably between <NUM> and <NUM>.

As methods for microencapsulation, core/shell-type particles are known, which have a catalytic core and a shell of a temperature-sensitive polymer having a LCST (lower critical solution temperature) or a Tg (glass-transition temperature) of a desired temperature (<NUM>-<NUM> in the present disclosure).

Here, a temperature-sensitive polymer with a lower critical solution temperature (LCST) is a polymer having the property of becoming soluble in a solvent at a temperature (LCST) or lower and causing aggregation at a temperature (LCST) or higher in the polymer solution. In the present disclosure, by using the above temperature-sensitive polymer in the shell portion, it is stable with respect to an aqueous solvent at room temperature (e.g., around <NUM>), but the shell portion collapses when the temperature exceeds the lower critical solution temperature by warming, and the catalyst of the core portion will elute and diffuse into the uncured coating film.

The temperature-sensitive polymer with a Tg (glass-transition temperature) is a polymer in which glass transition occurs at a certain temperature. In the present disclosure, by using the above temperature-sensitive polymer in the shell portion, the shell portion is formed at room temperature (e.g., around <NUM>), the shell portion fuses when the glass-transition temperature is exceeded by warming, and the catalyst of the core portion will elute and diffuse into the uncured coating film.

The temperature-sensitive polymer described above can be favorably used as long as the polymer has a LCST or a Tg at a certain temperature, but from the viewpoint of flexibility in designing resins, it is preferable that the Tg (glass-transition temperature) of the temperature-sensitive polymer is between <NUM> and <NUM>, and a Tg between <NUM> and <NUM> is more preferable. In addition, it is preferable to use an acrylic resin obtained by copolymerization of polymerizable unsaturated monomers.

Here, in the present disclosure, a Tg (glass-transition temperature) can be measured by DSC (differential scanning calorimetry).

Polymerizable unsaturated monomers with lower critical solution temperatures (LCST) include, for example, N-isopropyl acrylamide (LCST <NUM>), N-n propyl acrylamide (LCST <NUM>), N-n propyl methacrylamide (LCST <NUM>), N,N-diethyl acrylamide (LCST <NUM>) (Reference: <NPL>). In addition, N-substituted (meth)acrylamide derivatives that do not exhibit lower critical solution temperatures (LCST) include, for example, N,N-dimethyl (meth)acrylamide, hydroxyethyl (meth)acrylamide, acryloylmorpholine, N,N-dimethylaminopropylacrylamide, and the like. These polymerizable unsaturated monomers and N-substituted (meth)acrylamide derivatives may be used alone or in combinations of two or more species.

As a manufacturing method of the above core/shell type temperature-sensitive microencapsulation catalyst, a known method per se can be used without particular limitation. Specific examples include (<NUM>) a method in which a temperature-sensitive polymer and a catalyst are mixed, and then water is added to perform phase change emulsification, (<NUM>) a method in which a pre-emulsion of a monomer which is a precursor of a temperature-sensitive polymer is added dropwise and emulsion-polymerized after emulsifying the catalyst in an aqueous solution, (<NUM>) a method in which a pre-emulsion of a monomer that is a precursor of a temperature-sensitive polymer is added dropwise into an aqueous solution and emulsion-polymerized, and then encapsulated, (<NUM>) a method in which a monomer that is a precursor of a temperature-sensitive polymer and a catalyst are mixed in advance, and then added dropwise into an aqueous solution and emulsion-polymerized, and (<NUM>) a method in which a monomer that is a precursor of a temperature-sensitive polymer and a catalyst are mixed in advance to prepare a pre-emulsion, and then mini-emulsion polymerization is performed. An emulsifier can be used in any of the above methods.

Here, pre-emulsifying is the emulsification of a monomer solution by adding water (pure water, distilled water, ion-exchanged water, deionized water, etc.) and diluting it. The pre-emulsion may contain additives such as emulsifiers, neutralizers, polymerization initiators, and the like.

As a manufacturing method using the emulsion polymerization described as (<NUM>) to (<NUM>) above, for example, it can be carried out by emulsion polymerization by adding a pre-emulsion dropwise to water. The polymerization reaction is generally carried out at temperatures between <NUM> and <NUM>, and preferably between <NUM> and <NUM>.

Polymerizable unsaturated monomers which are generally used in the synthesis of acrylic resins can be used without particular limitation. Examples include styrene; non-functional (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl(meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, octyl (meth)acrylate, <NUM>-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, etc.; hydroxy group containing polymerizable unsaturated monomers such as <NUM>-hydroxyethyl (meth)acrylate, <NUM>-hydroxypropyl (meth)acrylate, <NUM>-hydroxypropyl (meth)acrylate, and <NUM>-hydroxybutyl (meth)acrylate; carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate; nitrogen-containing polymerizable unsaturated monomers containing no urethane bond such as adducts of (meth) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide or glycidyl (meth) acrylate and amines; polymerizable unsaturated monomers having a urethane bond such as reaction products of isocyanate group-containing polymerizable unsaturated monomers with hydroxyl group-containing compounds, and reaction products of hydroxyl group-containing polymerizable unsaturated monomers with isocyanate group-containing compounds; epoxy group-containing polymerizable unsaturated monomers such as glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, <NUM>,<NUM>-epoxycycyclohexylmethyl (meth) acrylate, <NUM>,<NUM>-epoxycyclohexylethyl (meth) acrylate, <NUM>,<NUM>-epoxycyclohexylpropyl (meth) acrylate, and allylglycidyl ether; (meth) acrylate having a polyoxyethylene chain with an alkoxy terminal; polymerized unsaturated monomers with a sulfonic acid group such as <NUM>-acrylamide-<NUM>-methylpropanesulfonic acid, <NUM>-sulfoethyl (meth) acrylate, allylsulfonic acid, <NUM>-styrenesulfonic acid, and sodium and ammonium salts of these sulfonic acids; polymerizable unsaturated monomers with a phosphate group such as <NUM>-acryloyloxyethylacid phosphate, <NUM>-methacryloyloxyethylacid phosphate, <NUM>-acryloyloxypropylacid phosphate, <NUM>-methacryloyloxypropylacid phosphate; polymerizable unsaturated monomers with an alkoxysillyl group such as vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tris (<NUM>-methoxyethoxy) silane, γ-(meth)acryloyloxypropyl triemethoxysilane, γ-(meth)acryloyloxypropyl triethoxysilane; perfluoroalkyl(meth)acrylates such as perfluorobutylethyl (meth)acrylate, perfluoroocthylethyl (meth)acrylate; polymerizable unsaturated monomers with a fluoroalkyl group such as fluoroolefin; polymerizable unsaturated monomers with a photopolymerizable functional group such as a maleimide group; (meth)acrylate having a polyoxyethylene chain with alkoxy terminal; polymerizable unsaturated monomers having two or more polymerizable unsaturated groups in one molecule such as allyl(meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, <NUM>,<NUM>-butylene glycol di(meth)acrylate, trimethylol propan tri(meth)acrylate, <NUM>,<NUM>-butanediol di(meth)acrylate, neopentyl glycol di(meth) acrylate, <NUM>,<NUM>-hexanediol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, glycerol di(meth)acrylate, <NUM>,<NUM>,<NUM>-tris(hydroxymethyl)ethane di(meth)acrylate, <NUM>,<NUM>,<NUM>-tris(hydroxymethyl)ethane tri(meth)acrylate, <NUM>,<NUM>,<NUM>-tris(hydroxymethyl)propane tri(meth)acrylate, triallyl isocyanurate, diallyl terephthalate, and divinylbenzene; polyalkylene glycol macromonomers such as polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate. These monomers may be used alone or in combinations of two more species. Among these monomers, the monomer having the tertiary amino group is preferred from the viewpoint of the coating properties of the cationic electrodeposition coating. In addition, from the viewpoint of creating a non-fragile shell, it is preferable to use a polymerizable unsaturated monomer having two or more polymerizable unsaturated groups per molecule, and/or to use a polymerizable unsaturated monomer having a high Tg (≧ <NUM>) at <NUM> or more by mass.

The emulsifiers described above include, but are not limited to, as long as the emulsifiers are used in the synthesis of acrylic emulsion, for example, cationic emulsifier, anionic emulsifier, nonionic emulsifier, and the like. These emulsifiers can be used alone or in combinations of two or more. Among these emulsifiers, cationic emulsifier is preferred.

The amount of the above emulsifier is preferably about <NUM> to <NUM>% by mass, more preferably about <NUM> to <NUM>% by mass, and further preferably about <NUM> to <NUM>% by mass, based on the total amount of all monomers used.

Polymerization initiators used in the synthesis of acrylic emulsion include, but are not limited to, organic peroxides, azo compounds, persulfates, and the like, which may be either of the oil-soluble or water-soluble type. These polymerization initiators can be used alone or in combinations of two or more.

The amount of the polymerization initiators which are used is generally about <NUM> to <NUM>% by mass, and more preferably about <NUM> to <NUM>% by mass, based on the total mass of all monomers which are used. The method of addition of the polymerization initiator is not particularly limited, and may be selected depending on the type and quantity, etc. thereof. For example, the polymerization initiators may be incorporated into a monomer mixture or an aqueous medium in advance, or may be added together or added dropwise during polymerization.

The resulting core/shell-type temperature-sensitive microencapsulated catalyst is water dispersible and can have an average particle size generally in the range of <NUM>-<NUM>, preferably in the range of <NUM>-<NUM>, and particularly preferably in the range of <NUM>-<NUM>.

In the present specification, the mean particle size of a temperature-sensitive microencapsulated catalyst is measured at <NUM> using a submicron particle size distribution analyzer after dilution with deionized water by conventional methods. For example, "COULTER N4 type" (trade name, manufactured by Beckman-Coulter) can be used as a device for measuring sub-micron particle size distributions.

In the present disclosure, it is preferable that the Michael addition reaction catalyst (C) is present within either the emulsion particle (A), the emulsion particle (B), or the microcapsule from the viewpoint of storage stability, and it is preferable that the Michael addition reaction catalyst (C) is not eluted in the aqueous solvent of the cationic electrodeposition coating composition. Therefore, the content of the Michael addition reaction catalyst (C) contained in the solvent component (supernatant liquid) when the cationic electrodeposition coating composition is centrifuged under the following conditions and separated into a solid component (mainly resin and pigment) and a solvent component is generally <NUM>% or less by mass, preferably <NUM>% or less by mass, and more preferably <NUM>% or less by mass, based on the blending quantity in the cationic electroporation coating composition. The catalyst (C) can be measured by conventional techniques well known to those skilled in the art, including, for example, gas chromatography and liquid chromatography.

The cationic electrodeposition composition is centrifuged at <NUM> and a relative centrifugal acceleration of <NUM>×<NUM><NUM> G for <NUM> hours.

The cationic electrodeposition coating compositions of the present disclosure may contain, as necessary, pigment dispersion pastes, resins (acrylic, epoxy, urethane, block isocyanate, and melamine resins), additives (surfactants, surface modifiers, neutralizers), solvents, and the like, as well as the essential ingredients, emulsion particles (A), emulsion particles (B), and Michael addition reaction catalysts (C).

The pigment dispersion paste is a pigment in which pigments such as coloring pigments, rust-preventive pigments, and extender pigments are dispersed in fine particles in advance, and for example, various additives such as pigment dispersing resins, pigments, and neutralizers can be prepared by blending various additives such as a pigment-dispersing resin, a pigment, and a neutralizing agent, and performing a dispersion treatment in a dispersion mixer such as a ball mill, a sand mill, and a pebble mill.

Known pigment dispersing resins can be used without particular limitation, and for example, epoxy resins or acrylic resins with hydroxyl and cationic groups, tertiary amine-type epoxy resins, quaternary ammonium salt-type epoxy resins, tertiary sulfonium salt-type epoxy resins, tertiary amine-type acrylic resins, quaternary ammonium salt-type acrylic resins, tertiary sulfonium salt-type acrylic resins, etc. can be used.

Known pigments can be used without particular limitation, e.g. colored pigments such as titanium oxide, carbon black, colcothar; constitutional pigments such as clay, mica, baryta, calcium carbonate, silica; anti-rust pigments, etc..

In addition, in the cationic electrodeposition coating compositions of the present disclosure, the pigment dispersion paste may be contained in the emulsion particles (A) or the emulsion particles (B).

The content of the pigment in the above pigment dispersion paste is preferably within the range of <NUM> to <NUM> parts by mass, and particularly preferably <NUM> to <NUM> parts by mass, per <NUM> parts by mass of the resin solids of the cationic electrodeposition coating composition.

The cationic electrodeposition coating composition of the present disclosure favorably contains more than <NUM>% by mass, preferably more than <NUM>% by mass, and more preferably more than <NUM>% by mass of water in the solvent. It can be said that the cationic electrodeposition coating composition is practically an aqueous coating composition.

In the cationic electrodeposition coating composition of the present disclosure, the percentage of the Michael addition reaction donor component (active hydrogen group-containing compound) contained in the emulsion particles (A) and the Michael addition reaction acceptor component (a compound having an α,β-unsaturated carbonyl group) contained in the emulsion particles (B) is generally <NUM>/<NUM> to <NUM>/<NUM>, and is preferably <NUM>/<NUM> to <NUM>/<NUM> in terms of the reactive functional group ratio (molar ratio) of the Michael addition reaction, which is favorable for obtaining a coating article with good storage stability and superior finished appearance and corrosion resistance.

Also, in the present disclosure, from the viewpoint of corrosion resistance, it is preferred that at least one of the compounds containing a coating active hydrogen group (A-<NUM>) or a compound having an α,β-unsaturated carbonyl group (B-<NUM>) is an epoxy resin with a weight average molecular weight of <NUM>,<NUM> or more. Alternatively, one may be an epoxy resin with a weight-average molecular weight of <NUM>,<NUM> or more, and the other may be a compound with a weight-average molecular weight of less than <NUM>,<NUM>.

The amine value of all of the resin contained in the coating is generally within the range of <NUM> to <NUM> KOH/g, and preferably <NUM> to <NUM> KOH/g, based on the resin solids content. By the blending ratio being within the above ranges, at least one of the aforementioned coating properties and coating performance will be superior.

The method for electrodeposition coating of the present disclosure includes immersing a substrate in an electrodeposition bath that includes a cationic electrodeposition coating composition, and conducting electrodeposition on the substrate by applying electricity to the substrate as a cathode.

The substrate to which the cationic electrodeposition coating composition of the present disclosure is applied includes an automobile body, two-wheeled vehicle components, household equipment, other equipment, and the like, and there is no particular limitation as long as it is a substrate that contains metal.

Metal steel sheets to be used as the substrate include cold-rolled steel sheets, alloyed hot dip galvanized steel sheets, electrolytic zinc-plated steel sheets, electrolytic zinc-iron two-layer plated steel sheets, organic composite plated steel sheets, aluminum materials, magnesium materials, as well as these metal sheets which are subjected to surface treatments such as phosphate chemical conversion treatment, chromate treatment, composite oxide treatment, etc. after the surfaces are cleansed by alkali-defatting, etc., as necessary.

The cationic electrodeposition coating composition can be coated onto a desired substrate surface by cationic electrodeposition coating. The cationic electrodeposition method is generally performed by diluting with deionized water, etc. to make a solids content of about <NUM> to <NUM>% by mass, preferably <NUM> to <NUM>% by mass. Further, the pH of the cationic electrodeposition coating composition is adjusted to be within a range from <NUM> to <NUM>, and preferably a range within <NUM> to <NUM>. The cationic electrodeposition coating composition is used as a bath, generally at a bath temperature of <NUM> to <NUM>, and an electric current is applied at a loading voltage of <NUM> to 400V, preferably <NUM> to 350V, with the substrate as a cathode. After electrodeposition coating, the coated substrate is washed thoroughly with ultrafiltrate (UF filtrate), reverse osmosis water (RO water), industrial water, pure water, etc. in order to remove excess cationic electrodeposition coating which is adhered on the substrate.

The thickness of an electrodeposition coating film is not particularly limited but can generally range from <NUM> to <NUM>, and preferably <NUM> to <NUM>, based on a dry coating film. In a baking drying process of the coating film, generally, the temperature of the surface of the coating is higher than <NUM> and lower than <NUM> using heating drying equipment such as an electric hot air dryer and a gas hot air dryer. In the present disclosure, a temperature of <NUM> to <NUM>, preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM> is favorable from the viewpoint of energy cost reduction.

In the case that a microencapsulated catalyst is used as the Michael addition reaction catalyst, it is preferred that the temperature of the coating surface is the Tg of the microcapsule or higher.

The baking time is generally <NUM> to <NUM> minutes, preferably <NUM> to <NUM> minutes, during which the electrodeposition film is heated.

A cured coating can be obtained by the aforementioned baking and drying.

In addition, in the present disclosure, electromagnetic induction heating can be used as a heating and drying facility from the viewpoint of energy cost reduction and processing time reduction.

In the case that the electromagnetic induction heating described above is used, the temperature of the coating surface is the same temperature as above (generally <NUM> to <NUM>, preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>), but the baking time is generally <NUM> to <NUM> minutes, preferably <NUM> to <NUM> minutes, and more preferably <NUM> to <NUM> minutes.

Hereinafter, the present disclosure will be described in greater detail by the examples of preparations, examples, and comparative examples below, but the present disclosure is not limited to these examples, In the Examples to be described below, the term "parts" indicates parts by mass, and the symbol "%" indicates mass%.

Manufacturing examples of each component used in the examples and the comparative examples are shown below.

<NUM> parts of bisphenol A and <NUM> parts of dimethylbenzylamine were added to <NUM> parts of jER828EL (trade name, manufactured by Mitsubishi Chemical Corporation, epoxy resin, epoxy equivalent weight <NUM>, number-average molecular weight <NUM>) in a flask equipped with a stirrer, a thermometer, a nitrogen-introducing tube, and a reflux condenser, and reacted at <NUM>° C until the epoxy equivalent weight was <NUM>. Then, <NUM> parts of diethylamine and <NUM> parts of ketiminated diethylenetriamine and methyl isobutyl ketone were added and reacted at <NUM> for <NUM> hours. Further, <NUM> parts of acetoacetic acid was added and reacted for <NUM> hours. The product of the reactions was adjusted with ethylene glycol monobutyl ether to obtain an active hydrogen group containing epoxy resin solution having a solids content of <NUM>%. The active hydrogen group-containing epoxy resin had an amine value of <NUM> KOH/g and a weight-average molecular weight of <NUM>,<NUM>.

<NUM> parts of hydrogenated bisphenol A, maleic acid adducts (compound obtained by adding <NUM> mol of hydrogenated bisphenol A and <NUM> mol of maleic acid), <NUM> parts of jER828EL (trade name, Mitsubishi Chemical Corporation, epoxy resin, epoxy equivalent <NUM>, number average molecular weight <NUM>), and <NUM> parts of dimethylbenzylamine were placed in a flask equipped with a stirrer, a thermometer, a nitrogen introducing tube, and a reflux condenser, and reacted at <NUM> for <NUM> hours. Next, <NUM> parts of diethylamine was added and reacted at <NUM> for <NUM> hours. The product of these reactions was adjusted with ethylene glycol monobutyl ether to obtain an α,β-unsaturated carbonyl group containing epoxy resin solution having a solids content of <NUM>%. The α,β-unsaturated carbonyl group containing epoxy resin had an amine value of <NUM> KOH/g and a weight average molecular weight of <NUM>,<NUM>.

<NUM> parts of jER828EL (trade names, Mitsubishi Chemical Co. , epoxy resin, epoxy equivalent <NUM>, number-average molecular weight <NUM>), <NUM> parts of bisphenol A and <NUM> parts of dimethylbenzylamine were placed in a flask equipped with a stirrer, a thermometer, and a reflux condenser, and reacted at <NUM> until an epoxy equivalent reached <NUM>. Next, <NUM> parts of diethanolamine and <NUM> parts of ketiminated compound of diethylenetriamine and methyl isobutyl ketone were added, and after reacting at <NUM> for <NUM> hours, <NUM> of ethylene glycol monobutyl ether was added to obtain an amino group containing epoxy resin solution having a solids content of <NUM>%. The amino group-containing epoxy resin had an amine value of <NUM> KOH/g and a weight-average molecular weight of <NUM>,<NUM>.

<NUM> parts of jER828EL (trade names, Mitsubishi Chemical Corporation, epoxy resin, epoxy equivalent <NUM>, a number-average molecular weight <NUM>), <NUM> parts of <NUM>,<NUM>,<NUM>,<NUM>-tetramethylguanidine, and <NUM> parts of isobutyl methyl ketone were placed in a flask equipped with a stirrer, thermometer, and reflux condenser, <NUM>, the mixture was warmed to <NUM>, and reacted for <NUM> hours. Then, isobutyl methyl ketone was added to prepare a solid component to obtain an amine catalyst (Michael Addition Reaction Catalyst) solution having a solids content of <NUM>%.

<NUM> parts of butyl cellosolve was placed in a reaction vessel equipped with a stirrer, a thermometer, a decanter, a reflux condenser, a nitrogen introducing tube, and a dropping funnel and was raised to <NUM> while introducing nitrogen gas, and a mixture of <NUM> parts of styrene, <NUM> parts of methyl methacrylate, <NUM> parts of butyl aminoethyl methacrylate, <NUM> parts of dimethylaminoethyl methacrylate, <NUM> parts of methoxy polyethylene glycol methacrylate, and <NUM> parts of t-butyl peroxy-<NUM>-ethylhexanoate was added dropwise over <NUM> hours. After dropping, a reaction was further conducted at <NUM> for <NUM> hour, the mixture was cooled, and the solution was adjusted with butyl cellosolve to obtain a tertiary amino group-containing acrylic resin having a solids content of <NUM>%. The Tg of the obtained resin was <NUM> and the amine value was <NUM> KOH/g.

<NUM> parts of the tertiary amino group-containing acrylic resin described above and <NUM> parts of the epoxy resin-added amine catalyst obtained in Manufacturing Example <NUM> were mixed. Further, an emulsion was formed by phase change by slowly adding ion-exchanged water while stirring vigorously. By evaporating the solvent under reduced pressure, a microencapsulated catalyst (Michael addition reaction catalyst) having a solids content of <NUM>% was obtained. The microencapsulated catalyst has a core-shell type microencapsulation structure with the aforementioned epoxy resin as a core portion and the aforementioned acrylic resin as a shell portion, and elution of the core portion (epoxy resin) begins when the temperature of the shell (acrylic resin) becomes greater than <NUM>, which is the Tg of the shell.

A reaction vessel was filled with <NUM> parts of COSMONATE M-<NUM> (trade name, manufactured by Mitsui Chemicals Corporation, crude MDI) and <NUM> parts of methylisobutyl ketone, and the mixture was heated to <NUM>. <NUM> parts of ethylene glycol monobutyl ether were added dropwise to this over <NUM> hour, and then heated to <NUM>. While maintaining this temperature, samples were taken over time to confirm that the absorption of the unreacted isocyanate group had ceased by infrared spectrophotometry, and a blocked polyisocyanate curing agent having a resin solids content of <NUM>% was obtained.

<NUM> parts oftrilene diisocyanate (TDI) and <NUM> parts of methyl isobutyl ketoxime (MIBK) were placed in a flask and heated to <NUM>. 520parts of <NUM>-ethylhexyl alcohol were added dropwise and reacted until the NCO value reached <NUM> to obtain a partial blocked isocyanate A having a resin content of <NUM>%.

Next, <NUM> parts of the partial blocked isocyanate A was taken out, <NUM> parts of dimethyl ethanolamine were added dropwise at <NUM>, and reacted until the mixture was practically free of NCO. After diluting with <NUM> parts of ethylene glycol monobutyl ether, the diluted mixture was neutralized with <NUM> parts of <NUM>% lactic acid to obtain lactic acid-neutralized amino group-containing blocked isocyanate B at a concentration of <NUM>%.

<NUM> parts of jER828EL (trade name, manufactured by Mitsubishi Chemical Corporation, epoxy resin, epoxy equivalent weight <NUM>, a number-average molecular weight <NUM>), <NUM> parts of bisphenol A and <NUM> parts of triphenylphosphonium iodide were added in another flask, and the mixture was reacted at <NUM>° C until the epoxy equivalent became <NUM>, then diluted with <NUM> parts of MIBK, and then <NUM> parts of the partial blocked isocyanate A was added and the mixture was reacted at <NUM> until the mixture was practically free of NCO.

Then, <NUM> parts of ethylene glycol monobutyl ether were added and cooled to <NUM>, <NUM> parts of the lactic acid neutralized amino group-containing block isocyanate B at a concentration of <NUM>% was added, and the mixture was reacted until the acid value became <NUM> KOH/g or less, and then propylene glycol monomethyl ether was added to adjust the solids content to obtain a pigment dispersion resin solution containing a quaternary ammonium base having a solids content of <NUM>%.

<NUM> parts of the pigment dispersion resin solution of Manufacturing Example <NUM> (<NUM> parts solids content), <NUM> parts of titanium oxide, <NUM> parts of purified clay, <NUM> parts of carbon black, and <NUM> parts of deionized water were mixed and dispersed by a ball mill for <NUM> hours to obtain a pigment dispersion paste No. <NUM> having a solids content of <NUM>%.

<NUM> parts of the pigment dispersion resin solution of Manufacturing Example <NUM> (<NUM> parts solids content), <NUM> parts of titanium oxide, <NUM> parts of purified clay, <NUM> parts of carbon black, <NUM> part of dioctyltin oxide, <NUM> part of bismuth hydroxide, and <NUM> parts of deionized water were mixed and dispersed by a ball mill for <NUM> hours to obtain a pigment dispersion paste No. <NUM> having a solids content of <NUM>%.

<NUM> parts of jER828EL (trade name, manufactured by Mitsubishi Chemical Corporation, epoxy resin, epoxy equivalent <NUM>, a number-average molecular weight <NUM>), <NUM> parts of bisphenol A and <NUM> parts of dimethylbenzylamine were placed in a flask equipped with a stirrer, a thermometer, a nitrogen-introducing tube, and a reflux condenser, and the mixture was reacted at <NUM> until the epoxy equivalent was <NUM>. Then, <NUM> parts of acetoacetic acid was added, reacted at <NUM> for <NUM> hours, and adjusted with ethylene glycol monobutyl ether to obtain an epoxy resin No.<NUM> solution having a solids content of <NUM>%. The active hydrogen-group-containing epoxides had an amine value of <NUM> KOH/g and a weight-average molecular weight of <NUM>,<NUM>.

<NUM> parts of jER828EL (trade names, Mitsubishi Chemical Corporation epoxy resin, epoxy equivalent <NUM>, a number-average molecular weight <NUM>) were placed in a flask equipped with a stirrer, a thermometer, and a reflux condenser, <NUM> parts of bisphenol A and <NUM> parts of dimethylbenzylamine were added, and the mixture was reacted at <NUM> until the epoxy equivalent was <NUM>. Then, <NUM> parts of diethanolamine and <NUM> parts of a ketiminated compound of diethylenetriamine and methyl isobutyl ketone were added, and after reacting at <NUM> for <NUM> hours, <NUM> of ethylene glycol monobutyl ether was added to obtain an epoxy resin No. <NUM> solution having a solids content of <NUM>%. Amino group-containing epoxy resin No. <NUM> had an amine value of <NUM> KOH/g and a weight average molecular weight of <NUM>,<NUM>.

<NUM> parts of Propylene glycol monomethyl ether and <NUM> parts of propylene glycol monobutyl ether were put in a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, and a dropping apparatus, heated while stirring and maintained at <NUM>. A mixture of <NUM> parts of "MPEG1000" (trade name, Methoxypolyethylene glycol monomethacrylate, Degussa Corporation, molecular weight approximately <NUM>), <NUM> parts of <NUM>-hydroxybutyl acrylate, <NUM> parts of dimethylaminoethyl methacrylate, <NUM> parts of styrene, <NUM> parts of isobornyl acrylate, <NUM> parts of methyl methacrylate, <NUM> parts of n-butyl acrylate, <NUM> part of azobis(isobutyronitrile) and <NUM> parts of propylene glycol monomethyl ether were added dropwise over <NUM> hours. After dropping, the solution was matured at <NUM> for <NUM> minutes, and then an additional catalytic mixture consisting of <NUM> parts of propylene glycol monomethyl ether and <NUM> parts of azobis(isobutyronitrile) was added dropwise over <NUM> hour. After aging at <NUM> for <NUM> hour and cooling, an acrylic resin solution having a solids content of <NUM>% was obtained. The amine value of the amino group containing acrylic resin was <NUM> KOH/g, and a weight average molecular weight was <NUM>,<NUM>.

<NUM> parts of jER828EL (trade name, Mitsubishi Chemical Corporation, epoxy resin, epoxy equivalent <NUM>, a number-average molecular weight <NUM>), <NUM> parts of <NUM>,<NUM>,<NUM>-triazabicyclo[<NUM>. <NUM>]deca-<NUM>-ene, <NUM> parts of isobutyl methyl ketone were placed in a flask equipped with a stirrer, thermometer, and reflux condenser, and the mixture was heated to <NUM> and reacted for <NUM> hours. Then, isobutyl methyl ketone was added to adjust the solids content to obtain an amine catalyst No. <NUM> (Michael addition reaction catalyst) solution having a solids content of <NUM>%.

<NUM> parts of butyl cellosolve were placed in a reaction vessel equipped with a stirrer, a thermometer, a decanter, a reflux a condenser, a nitrogen introducing tube, and a dropping funnel. The temperature was raised to <NUM> while introducing nitrogen gas, and a mixture of <NUM> parts of styrene, <NUM> parts of methyl methacrylate, <NUM> parts of butyl aminoethyl methacrylate, <NUM> parts of dimethylaminoethyl methacrylate, <NUM> parts of methoxy polyethylene glycol methacrylate, and <NUM> parts of t-butyl peroxy-<NUM>-ethylhexanoate was added dropwise over <NUM> hours. After dropping, the reaction was further conducted at <NUM> for <NUM> hour, the mixture was cooled and was adjusted with butyl cellosolve to obtain a tertiary amino group-containing acrylic resin having a solids content of <NUM>%. The obtained resin had a Tg of <NUM> and an amine value of <NUM> KOH/g.

<NUM> parts of the acrylic resin containing the tertiary amino group described above and <NUM> parts of the epoxy resin-added amine catalyst No. <NUM> obtained in Manufacturing Example <NUM> were mixed. Further, an emulsion was formed by phase change by slowly adding ion-exchanged water while stirring vigorously. A microencapsulated Catalyst No. <NUM> (Michael Addition Reaction Catalyst) having a solids content of <NUM>% was obtained by evaporating the solvent under reduced pressure.

Next, Examples and Comparative Examples will be described.

In each of the Examples and Comparison Examples, after each cationic electrodeposition coating composition (without pigment, and with pigment) was prepared, an electrodeposition coating plate was produced using the cationic electrodeposition coating composition with pigment.

The reasons for the production of pigmented and non-pigmented electrodeposition coated plates are as follows. It is difficult to accurately evaluate "pigmented" samples, since the particle size of pigment particles is also measured simultaneously in the evaluation of storage stability (particle size measurement) of only the resin particles described below, In addition, it is difficult to accurately evaluate "no pigment (clear coating)" samples, since the color adhesion of gauze cannot be evaluated in the evaluations of low-temperature curability described below.

<NUM> parts of the active hydrogen group containing epoxy resin solution obtained in Manufacturing Example <NUM> (<NUM> parts of solids), <NUM> parts of the amine catalytic solution obtained in Manufacturing Example <NUM> (<NUM> parts of solids), and <NUM> parts of <NUM>% formic acid were mixed, and the mixture was uniformly stirred. Thereafter, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component having a solids content of <NUM>%.

Then, <NUM> parts of an α,β-unsaturated carbonyl group containing epoxy resin solution (<NUM> parts of solids) acid obtained in Manufacturing Example <NUM> and <NUM> parts of <NUM>% formic were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (B) containing an Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the emulsion particles (A) and <NUM> parts of the emulsion particles (B) were mixed to obtain a cationic electrodeposition coating composition (no pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% the Pigment Dispersion Paste No. <NUM>, (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> parts of deionized water were mixed to the coating composition No. <NUM>-<NUM> above described to obtain a cationic electrodeposition coating composition No. <NUM>-<NUM> having a solids content of <NUM>% (with pigment).

Chemical treatment (trade name "Pulbond #<NUM>"; Japan Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the above cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>, and electrodeposition coated plates (two sheets baked and dried at temperatures of <NUM> and <NUM>) were obtained by baking and drying at <NUM> and <NUM> for <NUM> minutes. The surface roughness values (Ra) of the coated surfaces of the resulting electrodeposition coated plates were measured with a surface roughness meter (trade name "Surf Test <NUM>", manufactured by Mitsutoyo Corporation) with a cut-off of <NUM>. The surfaces had roughness values (Ra) of less than <NUM> and good finished appearances.

<NUM> parts of the active hydrogen group-containing epoxy resin solution (<NUM> parts of solids) obtained in Manufacturing Example <NUM>, <NUM> parts of <NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-nonene-<NUM> (DBN), and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component having a solids content of <NUM>%.

Then, <NUM> parts of an α,β-unsaturated carbonyl group containing epoxy resin solution (<NUM> parts of solids) with and <NUM> parts of <NUM>% formic acid obtained in Manufacturing Example <NUM> were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (B) containing a Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the emulsion particles (A) and <NUM> parts of the emulsion particles (B) described above were mixed, and a cationic electrodeposition coating composition (no pigment) No.<NUM>-<NUM> having a solids content of <NUM>% was obtained.

Then, <NUM> parts of <NUM>% pigment dispersion paste No.<NUM> (<NUM> parts of solids) obtained in Manufacturing Example <NUM>, and <NUM> parts of deionized water were added to obtain a cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Japan Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the above cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. Electrodeposition coated plates (two plates baked dry at <NUM> and <NUM>) were obtained by baking and drying at <NUM> and <NUM> for <NUM> minutes respectively. The surface of the resulting electrodeposition coated plates had surface roughness values (Ra) of less than <NUM> and a standard finished appearance.

<NUM> parts of the active hydrogen group containing epoxy resin solution (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component with <NUM>% of solids.

Then, <NUM> parts of an α,β-unsaturated carbonyl group containing epoxy resin solution (<NUM> parts of solids) obtained in Manufacturing Example <NUM> with and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain an emulsion particle (B) containing the Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the above emulsion particles (A), <NUM> parts of the emulsion particles (B), and <NUM> parts of the microencapsulated catalyst obtained in Manufacturing Example <NUM> were mixed to obtain a cationic electrodeposition coating composition (no pigment) No.<NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of the <NUM>% pigment dispersion paste No. <NUM> (<NUM> parts of solids) obtained in Manufacturing Example <NUM>, and <NUM> parts of deionized water were added to cationic electrodeposition coating composition No.<NUM>-<NUM> to obtain a cationic electrodeposition coating composition (with pigment) No.<NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Nihon Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. Electrodeposition coating was baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain electrodeposition coating plates (two sheets baked dry <NUM>°Cand <NUM>) with good finished appearances.

<NUM> parts of the active hydrogen group-containing epoxy resin No.<NUM> solution (<NUM> parts of solids) obtained in Manufacturing Example <NUM>, <NUM> parts of the amino group-containing acrylic resin solution (<NUM> parts of solids) obtained in Manufacturing Example <NUM>, and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component having a solids content of <NUM>%.

Then, <NUM> parts of EBECRYI,<NUM> (trade name, polyester acrylate with an average of <NUM> acrylate functional groups per molecule, average molecular weight: about <NUM>), <NUM> parts of the amino group-containing acrylic resin (<NUM> parts of solids) of Manufacturing Example <NUM>, and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was added dropwise slowly while stirring vigorously to obtain emulsion particles (B) containing a Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the emulsion particles (A), <NUM> parts of the emulsion particles (B) described above and <NUM> parts of the microencapsulated catalyst No. <NUM> of Manufacturing Example <NUM> were mixed to obtain a cationic electrodeposition coating composition (no pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% Pigment Dispersion Paste No. <NUM> (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> parts of deionized water were added to the coating composition No. <NUM>-<NUM> described above to obtain a cationic electrodeposition coating composition No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Nihon Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. The electrodeposition coating was baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain an electrodeposition coating plates with good finished appearances (two sheets baked dry at <NUM> and <NUM>).

Subsequently, <NUM> parts of EBECRYI,<NUM> (trade name, polyester acrylate having an acrylate functional group averaging <NUM> per molecule, a weight average molecular weight: about <NUM>), <NUM> parts of the epoxy-resin addition amine catalyst (<NUM> parts of solids) of Production Example <NUM>, <NUM> parts of the amino-group-containing acrylic resin solution (<NUM> parts solids) of Production Example <NUM>, and <NUM> parts of <NUM>% formic acid were blended, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (B) containing a Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the above emulsion particles (A) and <NUM> parts of the emulsion particles (B) were mixed to obtain a cationic electrodeposition coating composition (no pigment) No. <NUM>-<NUM> with a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% Pigment Dispersion Paste No. <NUM>-<NUM> (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> part deionized water were added to the Coating Composition No. <NUM>-<NUM> to obtain a cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Japan Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the cationic electrodeposit coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. The coated steel plates were baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain electrodeposition coated plates (two sheets baked dry at <NUM> and <NUM>) with good finished appearances.

<NUM> parts of the amino group-containing epoxy resin No.<NUM> solution(<NUM> parts solids) obtained in Manufacturing Example <NUM>, and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component having a solids content of <NUM>%.

Then, <NUM> parts of epoxy ester 3002A (trade name, Kyoei Chemical Co. , acrylic acid adduct of bisphenol A propylene oxide adduct diglycidyl ether, a weight-average molecular weight: approximately <NUM>), <NUM> parts of an amino group containing acrylic resin solution (<NUM> parts of solids) of Manufacturing Example <NUM>, and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was added dropwise slowly while stirring vigorously to obtain emulsion particles B containing a Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the above emulsion particle (A), <NUM> parts of the emulsion particle (B) and <NUM> parts of the microencapsulated catalyst No. <NUM> of Manufacturing Example <NUM> were mixed to obtain a cationic electrodeposition coating composition (no pigment) No.<NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% Pigment Dispersion Paste No. <NUM>, (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> part of deionized water were added to the above Coating Composition No. <NUM>-<NUM> to obtain a cationic electrodeposition coating composition (with Pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Nihon Percalizing Co. , zinc phosphate treatment agent) was applied to (cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the cationic electrodeposit coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. The coated steel plates were baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain an electrodeposition coated plates (two sheets baked dry at <NUM> and <NUM>) with good finished appearances.

<NUM> parts of the active hydrogen group containing epoxy resin solution (<NUM> parts solids) obtained in Preparation Example <NUM> and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component having a solids content of <NUM>%.

Then, <NUM> parts (<NUM> parts solids) of epoxy resin with an α,β-unsaturated carbonyl group obtained in Manufacturing Example <NUM> and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (B) containing an acceptor component of Michael addition reaction having a solids content of <NUM>%.

<NUM> parts of the above emulsion particles (A) and <NUM> parts of the emulsion particles (B) were mixed, and then a mixture of <NUM> parts of <NUM>,<NUM>-diazabicyclo[<NUM>,<NUM>,<NUM>]-nonene-<NUM> (DBN) and <NUM> part of EMULGEN <NUM> (trade name, Kao Co. , nonionic surfactant) was added to obtain a cationic electrodeposition coating composition (no pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% pigment dispersion paste No. <NUM> (<NUM> parts solids) obtained in Manufacturing Example <NUM> and <NUM> parts of deionized water were added to the cationic electrodeposition coating composition No. <NUM>-<NUM> to obtain a cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Nihon Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed with the cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. The coated steel plates were baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain electrodeposition coated plates (two sheets baked dry at <NUM> and <NUM>).

<NUM> parts of the active hydrogen group containing epoxy resin solution (<NUM> parts of solids) obtained in Preparation Example <NUM> and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (A) containing a Michael addition reaction donor component having a solids content of <NUM>%.

Then, <NUM> parts of the α,β-unsaturated carbonyl group containing epoxy resin (<NUM> parts of solids) obtained in Manufacturing Example 2and <NUM> parts of <NUM>% formic acid were mixed, and after uniform stirring, deionized water was slowly added dropwise while stirring vigorously to obtain emulsion particles (B) containing a Michael addition reaction acceptor component having a solids content of <NUM>%.

<NUM> parts of the above emulsion particles (A) and <NUM> parts of the emulsion particles (B) were mixed to obtain a cationic electrodeposition coating composition (no pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% pigment dispersion paste No. <NUM> (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> parts of deionized water were added to the cationic electrodeposition coating composition No. <NUM>-<NUM> to obtain a cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Nihon Percarising Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) × <NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. Electrodeposition coating was baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain an electrodeposition coated plates (two sheets baked dry at <NUM> and <NUM>) with good finished appearance.

<NUM> parts of the amino group-containing epoxy resin solution (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> parts (<NUM> parts solids) of the blocked polyisocyanate curing agent obtained in Manufacturing Example <NUM> were mixed, further mixed with <NUM> parts of <NUM>% acetic acid, and uniformly stirred. Then, <NUM> parts of deionized water were added dropwise over about <NUM> minutes while stirring vigorously to obtain a cationic electrodeposition coating composition (no pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Then, <NUM> parts of <NUM>% pigment dispersion paste No. <NUM> (<NUM> parts of solids) obtained in Manufacturing Example <NUM> and <NUM> parts deionized water were added to <NUM> parts of the above cationic electrodeposition coating composition No. <NUM>-<NUM> (<NUM> parts solids) to obtain a cationic electrodeposition coating composition (with pigment) No. <NUM>-<NUM> having a solids content of <NUM>%.

Chemical treatment (trade name "Pulbond #<NUM>"; Nihon Percalizing Co. , zinc phosphate treatment agent) was applied to cold-rolled steel plates (<NUM> (long) ×<NUM> (wide) × <NUM> (thick)) as a coating substrate. Electrodeposition coating was performed using the above cationic electrodeposit coating composition (with pigment) No. <NUM>-<NUM> to make a dry film having a thickness of <NUM>. The coated steel plates were baked and dried at <NUM> and <NUM> for <NUM> minutes respectively to obtain electrodeposit coated plates (two sheets baked dry at <NUM> and <NUM>) with good finished appearances.

The cationic electrodeposition coating compositions (no pigment, with pigment) obtained in the above examples and comparative examples were evaluated by the evaluation tests described below. The results are shown in Table <NUM> and Table <NUM>.

If at least one of the two evaluation tests failed with a result of "D", the coating is considered to be a failure. Evaluations were conducted with pigmented or non-pigmented coatings, but if either failed with a result of "D", all coating in the series were considered to be failures.

The particle size changes before and after storage of the cationic electrodeposition coating compositions (no pigment) obtained in the examples and comparative examples were compared after storage for <NUM> month at a temperature of <NUM>.

"COULTER N4 type" (trade name, manufactured by Beckman Coulter K. ) was used to measure the particle size. As for the evaluation, A to C pass, and D fails.

The cationic electrodeposition coating compositions obtained in the examples and comparative examples (with pigments) were applied on glass plates in an applicator such that the thickness of dry coatings was <NUM>, and heated at <NUM> for <NUM> minutes. Then, rubbing treatment was performed by reciprocating five times with a load of <NUM> using gauze impregnated with acetone. Low-temperature curability was evaluated by assessing the status of the gauze and the coatings according to the following criteria. As for the evaluation, A to C pass, and D fails.

Claim 1:
A cationic electrodeposition coating composition comprising:
an emulsion particle (A) containing a Michael addition reaction donor component and an emulsion particle (B) containing a Michael addition reaction acceptor component,
wherein a Michael addition reaction catalyst (C) is contained in the emulsion particle (A) or the emulsion particle (B) or is contained in the cationic electrodeposition coating composition by being microencapsulated.