JP2008231142A - Cationic electrodeposition-coating composition, cationic electrodeposition-coating composition for supplement and method for supplementing electrodeposition-coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cationic electrodeposition-coating composition dispersing a solid-curing catalyst well and excellent in dispersion stability, and the cationic electrodeposition-coating composition for supplement. <P>SOLUTION: This cationic electrodeposition-coating composition contains (a) an amine-modified epoxy resin; (b) a block isocyanate-curing agent; and (c) an aqueous dispersion type catalyst having 50 to 200 nm mean particle diameter and containing the solid-curing catalyst and a nonionic surfactant. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cationic electrodeposition coating composition containing a water-dispersed curing catalyst in which a solid curing catalyst is dispersed in an aqueous solvent.

  Cationic electrodeposition coating is a coating method performed by immersing an object to be coated as a cathode in a cationic electrodeposition coating composition and applying a voltage. In this method, even an object to be coated having a complicated shape can be applied to the details, and can be applied automatically and continuously. It has been widely put into practical use as an undercoating method for objects to be coated. Furthermore, electrodeposition coating can give high anticorrosive properties to the object to be coated, and is excellent in the protective effect of the object to be coated.

  The cationic electrodeposition coating composition is generally a coating composition containing an amine-modified epoxy resin, a blocked isocyanate curing agent and a curing catalyst. Conventionally, a lead compound has been used as the curing catalyst. By using a lead compound as a curing catalyst, there is an advantage that a cured electrodeposition coating film having a high crosslinking density and Tg can be obtained. However, since lead has an adverse effect on the environment, reduction of the amount of use has been demanded in recent years. Therefore, so-called lead-free cationic electrodeposition coatings that do not contain lead are mainly used. In such lead-free cationic electrodeposition coating compositions, curing catalysts such as tin compounds are widely used. Such curing catalysts are generally both solid and liquid.

  In the case of using a solid curing catalyst that is in a solid state, generally, a pigment dispersion resin is often used together with a pigment to be dispersed in an aqueous solvent at a high concentration in advance to form a paste. This is because it is difficult to disperse a solid substance in a single step in a low concentration uniform state used in an electrodeposition coating composition. However, when the solid curing catalyst is dispersed together with the pigment, there is a problem based on the difference in dispersibility between the solid curing catalyst and the pigment. In general, many solid curing catalysts are inferior in dispersibility than pigments. Therefore, when preparing a paste by dispersing the solid curing catalyst together with the pigment, if the dispersion is terminated when the pigment is dispersed, the solid curing catalyst is not sufficiently dispersed and the solid curing catalyst settles with time. was there. On the other hand, when the dispersion is terminated when the solid curing catalyst is sufficiently dispersed, there is a problem that the pigment is overdispersed and the resulting paste is thickened. Furthermore, in this case, since it is necessary to prepare a large amount of paste over a long period of time, it is disadvantageous in terms of preparation cost. For this reason, the method of disperse | distributing a solid curing catalyst favorably is calculated | required.

  International Publication No. WO99 / 31187 (Patent Document 1) is an aqueous dispersion obtained by mixing and dispersing a bismuth compound and an organic acid in an aqueous medium, and the organic acid-modified bismuth compound exists in a water-insoluble form. A cationic electrodeposition coating composition comprising an aqueous dispersion is described (claim 1). The aqueous dispersion contained in the cationic electrodeposition coating composition of Patent Document 1 is characterized by being prepared using a bismuth compound and an organic acid. The bismuth compound also functions as a curing catalyst, as described in detail later in this specification. However, since these bismuth compounds and organic acids are present in the cationic electrodeposition coating composition as organic acid salts, the conductivity of the electrodeposition coating composition is increased, and as a result, there is a possibility that problems may occur in electrodeposition coating. There is.

  JP 2002-129100 A (Patent Document 2) describes a cationic electrodeposition coating composition containing a bismuth / acetylacetone complex. However, this bismuth / acetylacetone complex is used to control the gloss of the electrodeposition coating film, which is different from the present invention.

  Japanese Patent Application Laid-Open No. 2004-137365 (Patent Document 3) describes a cationic electrodeposition paint containing bismuth salicylate. However, in this electrodeposition coating, bismuth salicylate is also used to lower the gloss value of the electrodeposition coating film, which is different from the present invention.

  Japanese Patent Application Laid-Open No. 2004-137367 (Patent Document 4) describes a cationic electrodeposition paint containing a colloidal bismuth metal. However, in this electrodeposition paint, colloidal bismuth metal is also used to lower the gloss value of the electrodeposition coating film, which is different from the present invention.

  Furthermore, the electrodeposition coating using the cationic electrodeposition coating composition is performed by immersing the article to be coated as a cathode as described above and precipitating solids or the like on the article to be coated. For this reason, unlike other coating compositions that are applied by spraying the coating composition on the object to be coated, the solid content of the paint and the pigment concentration in the electrodeposition coating composition in the electrodeposition tank change depending on the application. There's a problem. Therefore, replenishment cationic electrodeposition coating composition for easily adjusting the coating solid content and pigment concentration of the electrodeposition coating composition in the electrodeposition tank, and further, no precipitate is generated without stirring. There is also a need for a cationic electrodeposition coating composition for replenishment with less sediment.

International Publication No. WO99 / 31187 JP 2002-129100 A JP 2004-137365 A JP 2004-137367 A

  The present invention solves the above-mentioned conventional problems, and the object of the present invention is to provide a cationic electrodeposition coating composition in which a solid curing catalyst is well dispersed and excellent in dispersion stability, and a replenishing cation. The object is to provide an electrodeposition coating composition.

The present invention
An amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and
A water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, comprising a solid curing catalyst and a nonionic surfactant;
A cationic electrodeposition coating composition containing the above, whereby the above object is achieved.

  The solid curing catalyst contained in the water-dispersed curing catalyst (c) is more preferably a tin compound or a bismuth compound.

  More preferably, the water-dispersed curing catalyst (c) further contains a compound selected from the group consisting of fatty acids, fatty acid derivatives, amine compounds and one or a mixture of two or more thereof.

  The present invention also provides an amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and a water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, comprising a solid curing catalyst and a nonionic surfactant; And a one-component replenishment cationic electrodeposition coating composition having a coating solid content concentration of 30 to 50% by weight.

The present invention is also a two-component replenishment cationic electrodeposition coating composition comprising:
A binder resin emulsion in which the first liquid of the two-component replenishment cationic electrodeposition coating composition contains a water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, which contains a solid curing catalyst and a nonionic surfactant. A second liquid of the two-liquid replenishment cationic electrodeposition coating composition is a pigment dispersion paste liquid,
A cationic electrodeposition coating composition for two-component replenishment is also provided.

  The present invention further provides a method for replenishing an electrodeposition coating composition comprising the step of placing the cationic liquid electrodeposition coating composition for replenishing one liquid or the cationic electrodeposition coating composition for replenishing two liquids into an electrodeposition tank. .

  The cationic electrodeposition coating composition of the present invention is a water dispersion type containing a solid curing catalyst and a specific amount of a nonionic surfactant, and contains a water dispersion type curing catalyst (c) having a specific average particle size. . This water-dispersed curing catalyst (c) has a feature that the dispersion stability is very excellent. When the solid curing catalyst is included in the cationic electrodeposition coating composition, a method of preparing a pigment dispersion paste by dispersing both the solid curing catalyst and the pigment is generally used. However, this method often causes problems such as precipitation of the solid curing catalyst or thickening of the pigment dispersion paste, and further has a problem that the appearance of the cured electrodeposition coating film obtained by these problems deteriorates.

  In the cationic electrodeposition coating composition of the present invention, by using the water-dispersed curing catalyst (c), it is possible to disperse the pigment and the solid curing catalyst under optimum conditions according to their dispersibility. Become. Therefore, the cationic electrodeposition coating composition can be more easily prepared without problems such as precipitation of the solid curing catalyst, thickening of the pigment paste, and deterioration of the appearance of the coating film derived therefrom. The present invention provides a cationic electrodeposition coating composition that is excellent in dispersion stability and can provide a coating film having a good coating film appearance.

  Furthermore, by using the above water-dispersed curing catalyst (c), it can be used favorably for the preparation of the coating solid content, pigment concentration, etc. of the electrodeposition coating composition in the electrodeposition tank, and has excellent dispersion stability. A cationic electrodeposition coating composition can be prepared. This makes it possible to replenish the electrodeposition coating composition with the one-component replenishment cationic electrodeposition coating composition.

Cationic electrodeposition coating composition The cationic electrodeposition coating composition of the present invention contains a binder resin containing an amine-modified epoxy resin (a) and a blocked isocyanate curing agent (b), and a curing catalyst. In the cationic electrodeposition coating composition of the present invention, the contained curing catalyst is a water dispersion type containing a solid curing catalyst and a specific amount of a nonionic surfactant, and has a specific average particle diameter. It is a dispersion-type curing catalyst (c). The cationic electrodeposition coating composition of the present invention may further contain a pigment and other components as required.

Water-dispersed curing catalyst (c)
The cationic electrodeposition coating composition of the present invention contains a water-dispersed curing catalyst (c). This water-dispersed curing catalyst (c) is a curing catalyst in which a solid curing catalyst is dispersed in an aqueous solvent. This water-dispersed curing catalyst (c) includes a solid curing catalyst, a nonionic surfactant, and an aqueous solvent. The solid curing catalyst contained in the water-dispersed curing catalyst (c) can promote dissociation of the blocking agent of the blocked isocyanate curing agent (b), and further improves the crosslinking density and Tg of the resulting cured electrodeposition coating film. Can be made.

  As the solid curing catalyst, a solid curing catalyst usually used for the purpose of promoting dissociation of the blocking agent of the blocked isocyanate curing agent (b) can be used. A typical solid curing catalyst is a tin compound. Examples of the tin compound used as the solid curing catalyst include dibutyltin oxide, dioctyltin oxide, monobutyltin oxide, monooctyltin oxide, and mixtures thereof. Examples of solid curing catalysts other than tin compounds include bismuth compounds such as bismuth hydroxide, bismuth oxide, bismuth lactate, and bismuth silicate.

  The “solid” in the solid curing catalyst in the present specification may be solid in a normally used environment. For example, it is solid even at 50 ° C., that is, the shape is maintained. means. “Solid” as used herein includes both a crystalline state and an amorphous state (so-called amorphous).

  In the present invention, a tin compound or a bismuth compound is preferably used as the solid curing catalyst. These solid curing catalysts are excellent in the dissociation promoting performance of the blocking agent. From the viewpoint of the environment, it is particularly preferable to use bismuth hydroxide as the solid curing catalyst. By using bismuth hydroxide as a solid curing catalyst, it is possible to provide an excellent blocking agent dissociation promoting property and to prepare a cationic electrodeposition coating composition having extremely high environmental safety.

  Unlike the prior art, bismuth hydroxide preferably used in the present invention has excellent properties as a solid curing catalyst. In the present invention, by using bismuth hydroxide as a solid curing catalyst, a cationic electrodeposition coating composition having excellent dispersion stability and excellent blocking agent dissociation accelerating property and extremely high environmental safety can be obtained. It becomes possible to prepare.

  Examples of the nonionic surfactant contained in the water-dispersed curing catalyst (c) include ether-type, ester-type, ether-ester-type, and alcohol-type surfactants. More specifically, polyoxypropylene-polyoxyethylene (PO-EO) copolymer addition compounds, various higher alcohols, aromatic ethoxylate (EO) addition type compounds, fatty acid ester type compounds, fatty acid amides, and these ethoxys Rate (EO) addition type compounds, polyglycerin fatty acid esters and the like.

  In the present invention, among the nonionic surfactants, (PO-EO) copolymer addition compounds are more preferably used. These nonionic surfactants are more preferable because they are excellent in the dispersion ability of the solid curing catalyst and can prepare a water-dispersed curing catalyst (c) that is superior in dispersion stability.

  Examples of the aqueous solvent contained in the water-dispersed curing catalyst (c) include commonly used water such as ion-exchanged water. The aqueous solvent may further contain a water-miscible organic solvent such as a low molecular weight alcohol or a low molecular weight glycol, if necessary. However, the nonionic surfactant is not included in the water-miscible organic solvent referred to herein.

  The water-dispersed curing catalyst (c) in the present invention can be prepared, for example, by adding a solid curing catalyst and a nonionic surfactant to water and dispersing them using a dispersion mixer such as an SG mill or a ball mill. . The amount of the solid curing catalyst contained in the water-dispersed curing catalyst (c) is preferably 5 to 60 parts by weight with respect to 100 parts by weight of the water-dispersed curing catalyst (c). When the amount of the solid curing catalyst is less than 5 parts by weight, since the concentration is low, the amount of the water-dispersed curing catalyst (c) for obtaining the required amount of catalyst is increased, which is inefficient. . On the other hand, when the amount of the solid curing catalyst exceeds 60 parts by weight, it may be difficult to obtain a water dispersion form.

  The water-dispersed curing catalyst (c) used in the present invention has a mean particle size of 50 to 200 nm. The average particle size is more preferably 100 to 200 nm. It is not preferable from the viewpoint of production efficiency and the like to prepare a water-dispersed curing catalyst (c) having an average particle size of less than 50 nm. On the other hand, when the average particle size exceeds 200 nm, there is a problem that the dispersion stability is deteriorated. The average particle size of the water-dispersed curing catalyst (c) is a value measured by a laser light scattering method and is displayed as a volume average particle size.

  The water-dispersed curing catalyst (c) having an average particle diameter of 50 to 200 nm is obtained by, for example, mixing a solid curing catalyst having an average particle diameter of 2 to 10 μm and a nonionic surfactant with a disperser, preferably a sand grind mill (SG mill). , Can be prepared by mixing. The amount of the nonionic surfactant used in the preparation of the water-dispersed curing catalyst (c) is preferably 0.5 to 100 parts by weight, more preferably 5 to 100 parts by weight based on 100 parts by weight of the solid curing catalyst. More preferred. By using the nonionic surfactant in such an amount, it is possible to prepare a water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm and a very small particle size. When the content of the nonionic surfactant is less than 0.5 parts by weight, the average particle size of the dispersion of the solid curing catalyst contained in the water-dispersed curing catalyst (c) becomes larger and the dispersion stability is poor. There is a fear. On the other hand, when the content of the nonionic surfactant exceeds 100 parts by weight, there is no further effect of improving dispersion, which is meaningless.

  Further, in the preparation of the water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, the solid curing catalyst used as a raw material preferably has an average particle size of 2 to 20 μm. In the preparation of the water-dispersed curing catalyst (c), a water-dispersed curing catalyst (c) having a smaller average particle diameter can be prepared by using a solid curing catalyst having such an average particle diameter as a raw material. This is because it becomes possible.

  Furthermore, it is preferable to use a sand grind mill as a disperser. In this dispersion step, it is more preferable to use harder beads such as beads made of zirconium or zircon (zirconium silicate). Bismuth compounds generally have a high hardness. Therefore, the use of beads made of zirconium or zircon makes it possible to prepare a water-dispersed curing catalyst (c) having a smaller average particle diameter. The beads used in this dispersion step are more preferably those having a diameter of 2.0 mm or less.

  The water-dispersed curing catalyst (c) thus obtained is an amount such that the content of the solid curing catalyst is in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition. It is more preferable that it is contained in the cationic electrodeposition coating composition. If the solid curing catalyst content is less than 0.1 parts by weight with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition, the resulting coating film may not be cured sufficiently. In addition, when the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition is used in an amount exceeding 10 parts by weight, there is a possibility that catalyst curing corresponding to the amount cannot be obtained. The “resin solid content” in the present specification means the resin solid content in the coating composition containing the amine-modified epoxy resin (a), the blocked isocyanate curing agent (b), and the pigment dispersion resin described later.

  In preparing the water-dispersed curing catalyst (c), additives such as an antifoaming agent and a reactive crosslinking agent can be dispersed together as necessary. By dispersing these additives in combination with a solid curing catalyst, these additives can also be uniformly dispersed in the cationic electrodeposition coating composition, thereby making the cured electrodeposition coating film excellent in coating film appearance. There is an advantage that can be formed.

Fatty acids or amine compounds The water-dispersed curing catalyst (c) is optionally mixed with fatty acids, fatty acid derivatives (both referred to as fatty acids), amine compounds, and one or a mixture of two or more thereof. A compound selected from the group consisting of: (hereinafter sometimes simply referred to as “fatty acids or amine compounds”) may be included. When the fatty acid or amine compound is contained in the water-dispersed curing catalyst (c), the dispersion stability of the solid curing catalyst contained in the water-dispersed curing catalyst (c) is further improved and left standing. However, it is possible to produce a water-dispersed curing catalyst with little sediment or no sediment. In the preparation of the water-dispersed curing catalyst (c), when fatty acids or amine compounds are used, they can be used by adding them in the same manner as the nonionic surfactant.

  The fatty acids are fatty acids or derivatives thereof as described above. Examples of fatty acids include linear saturated fatty acids, branched saturated fatty acids, and unsaturated fatty acids. Examples of fatty acid derivatives include fatty acid esters obtained by modifying the above fatty acids with alcohol, polyhydric alcohols (glycerin, ethylene glycol, polyethylene glycol, etc.), fatty acid ethylene oxide adducts or fatty acid propylene oxide modified with ethylene oxide or propylene oxide. Adducts, fatty acid amide compounds modified with amine compounds, and polyfunctional fatty acids are included. These fatty acid esters or fatty acid amide compounds also include those obtained by ring-opening addition of ethylene oxide (ethylene oxide ring-opening adduct). These fatty acids contain chemical bonds such as unsaturated bonds, ether bonds and ester bonds, functional groups such as hydroxyl groups, amino groups and carbonyl groups, and heteroatoms such as oxygen, nitrogen, sulfur and halogen in the molecular skeleton. You may go out. Polyfunctional carboxylic acids and the like are also included in the fatty acid derivatives. As fatty acid derivatives, it is more preferable to use fatty acid esters, fatty acid amide compounds, and these ethylene oxide ring-opening adducts.

  The fatty acids used in the present invention are preferably fatty acids having 4 to 22 carbon atoms and derivatives thereof, more preferably fatty acids having 7 to 20 carbon atoms and derivatives thereof.

Specific fatty acids include, for example, the following compounds:
(1) Linear saturated fatty acid arachidic acid, tricosanoic acid, behenic acid, heneicosanoic acid, eicosanoic acid, nonadecanoic acid, stearic acid, heptadecanoic acid, palmitic acid, pentadecanoic acid, myristic acid, tridecanoic acid, lauric acid, capric acid, capryl Acid, octanoic acid, heptanoic acid, hexanoic acid, valeric acid, butyric acid, etc., refined stearic acid (450V, 550V, 700V), etc. manufactured by Kao Corporation;
(2) Branched saturated fatty acid isostearic acid, methyltetradecanoic acid, methylheptadecanoic acid, methyloctadecanoic acid, isovaleric acid and the like;
(3) unsaturated fatty acid oleic acid, ricinoleic acid, linoleic acid, linolenic acid, eleostearic acid, elaidic acid, palmitoleic acid, arachidonic acid, undecenoic acid, sorbic acid, crotonic acid and the like;
(4) Multifunctional carboxylic acid suberic acid, azelaic acid, sebacic acid, brassylic acid, phthalic acid, dodecanedioic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, 3-tert-butyl Adipic acid, trimellitic acid, pyromellitic acid, etc .;
(5) Hetero atom-containing fatty acid hexyloxyacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, salicylic acid, benzoic acid, p-butoxybenzoic acid, N-acetylglycine, N-acetyl-β-alanine, thioctic acid and the like;
(6) Fatty acid ester (alcohol ester type)
Lion's Kadenax (GS-90, SO-80C), Kao's Rheodor (SP-L10, SP-P10, SP-S10V, SP-S30V, AS-10, AO-10, AO-15V), Kao Rheodor Super SP-L10 manufactured by Kao, Emazol manufactured by Kao Corporation (L-10 (F), P-10 (F), S-10V, O-10V), etc .;
(7) Fatty acid ester (ethylene glycol, polyethylene glycol ester type)
Lion Rionon (DT-600S, DEH-40), Asahi Denka Kogyo Adekaestor (OEG-102, OEG-106), etc .;
(8) Fatty acid methyl ester (ethylene oxide, propylene oxide addition system)
Lion Leo Fat (LA-110M-95, OC-0503M), Kao Emanon (1112,3199,3299,4110, CH-25, CH-40, CH-60 (K), CH-80), etc. (9) Fatty acid ethylene oxide adducts Lion's Esophat (O / 15, O / 20,60 / 15), Asahi Denka Kogyo's Adekaestor (TL-144, TL-161, TL-162, S-60, S-80, T-81, T-82), Kao Rheodor (TW-L120, TW-L106, TW-P120, TW-S120V, TW-S106, TW-S320V, TW-O120V, TW-O106V, TW-O320V, TW-IS399C, 430,440,460), Kao's Leodoll Super TW-L120, etc .;
(10) Fatty acid ester (glycerin ester type)
(11) Fatty acid amide compounds such as Kao's Exel T-95, VS-95, O-95R, 200, 300, 122V, P-40S) and Kao's Rheodor (MS-50, MS-60, MO-60, MS165V) A saturated fatty acid monoamide compound that is lauric acid amide, stearic acid amide, palmitic acid amide, caproic acid amide, caprylic acid amide, capric acid amide, myristic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like;
(12) Unsaturated fatty acid monoamide oleic acid amide, erucic acid amide, ricinoleic acid amide, palmitic acid amide, behenic acid amide, brassinic acid amide, esylic acid amide, linoleic acid amide, linolenic acid amide, rice sugar Examples of these industrial products such as fatty acid amide and palm fatty acid amide include Kao wax (EB-G, EB-P, EB-FF, 85-P, 220, 230-2) manufactured by Kao Corporation, and fatty acid amide manufactured by Kao Corporation. S, T, ON, E), Adekasol YA manufactured by Asahi Denka Kogyo Co., Ltd. and the like;
(13) Saturated fatty acid bisamides that are fatty acid amide compounds, methylene bis-stearic acid amide, ethylene bis-capric acid amide, ethylene bis-lauric acid amide, ethylene bis-stearic acid amide, ethylene bis-isostearic acid amide, ethylene bis-hydroxystearic acid amide, ethylene Bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene bishydroxystearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, methylene Bispalmitic acid amide, ethylene bispalmitic acid amide, methylene bisbehenic acid amide, ethylene bisbehenic acid amide, hexaethylene bispalmitic acid amide, etc .;
(14) Unsaturated fatty acid bisamides that are fatty acid amide compounds, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, and the like;
(15) Substituted amides which are fatty acid amide compounds N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid Acid amides;
(16) Aromatic bisamides methylol stearic acid amides which are fatty acid amide compounds; methylol amides such as methylol behenic acid amide, N, N-distearylisophthalic acid amide, metaxylylene bis stearic acid amide;
(18) Branched amides which are fatty acid amide compounds N′-2-hydroxyethyl stearamide, N.I. N'-ethylenebisoleic acid amide, N.I. N'-xylenebisstearic acid amide, N.I. N′-dioleoyl adipamide, N.I. N′-dioleoyl sebacic acid amide, N.I. N′-distearyl isophthalic acid amide and the like;
(19) Alkanolamides which are fatty acid amide compounds: coconut oil fatty acid monoethanolamide, lauric acid monoethanolamide, myristic acid monoethanolamide, oleic acid monoethanolamide, coconut oil fatty acid diethanolamide, lauric acid diethanolamide, myristic acid diethanolamide Industrial products such as lime, dioleamide, oleic acid diethanolamide, palm oil fatty acid monopropanolamide, lauric acid monopropanolamide, myristic acid monopropanolamide, oleic acid monopropanolamide, polyoxyalkylene alkanolamide ), Lion's armor slip (CP, E, EY), etc .;
However, it is not limited to these.

  The amine compound is preferably an amine compound in which an alkyl chain having 4 or more carbon atoms is bonded to a nitrogen atom. There may be one alkyl chain bonded to the nitrogen atom, or two or more alkyl chains may be bonded. As these amine compounds, any of primary, secondary and tertiary amines may be used. These amine compounds may have a plurality of amino groups in the skeleton, or the skeleton itself may be modified with ethylene oxide or the like. The amine compound used in the present invention preferably has 4 to 22 carbon atoms in the alkyl chain, more preferably 7 to 20 carbon atoms in the alkyl chain.

Specific examples of amine compounds include the following:
(1) Primary amine compound (1-1) Aliphatic mono- and polyamine compounds
n-butylamine, amylamine, n-hexylamine, heptylamine, n-octylamine, nonylamine, laurylamine, tetradecylamine, cetylamine, stearylamine, 2,4-butanediamine, 1,6-hexamethylenediamine, 1, Aliphatic primary amine compounds such as 8-octamethylenediamine,
(1-2) Alicyclic mono- and polyamine compounds cyclohexylamine, 1,3- and 1,4-diaminocyclohexane, 1,3- and 1,4-bis (aminomethyl) cyclohexane, 3-aminomethyl-3, Alicyclic primary amine compounds such as 5,5-trimethyl-1-aminocyclohexane, bis (4-aminocyclohexyl) methane, 1-methyl-2,4-diaminocyclohexane, 1-methyl-2,6-diaminocyclohexane Kind,
(1-3) Aromatic mono- and polyamine compounds aniline, meta and paratoluidine, naphthylamine, 1,3- and 1,4-phenylenediamine, 1-methyl-2,4-diaminobenzene, 1-methyl-2,6 -Aromatic primary amine compounds such as diaminobenzene, 2,4,-and 4,4, -diaminodiphenylmethane, 4,4, -diaminobiphenyl, 1,5- and 2,6-naphthalenediamine,
(1-4) Aralkyl mono and polyamine compounds
Aralkyl primary amine compounds such as 1,3- and 1,4-bis (aminomethyl) benzene, 1,5- and 2,6-bis (aminomethyl) naphthalene,
These industrial products include Lion's Armin CD, OD, TD, HT, 8D, 12D, 14D, 16D, 18D), Kao's Farmin (CS, 08D, 20D, 80, 86T, O, T), etc. Listed;
(2) Secondary amine compounds di-n-butylamine, diisoamylamine, dibenzylamine, methyldiethylethylenediamine, methylaniline, piperidine, 1,2,3,4-tetrahydroisoquinoline, 6-methoxy-1,2,3 Secondary amines such as, 4-tetrahydroisoquinoline, morpholine, N-methyl-glucamine, glucosamine, t-butylamine,
These industrial products include Kao's Farmin (D86) and the like;
(3) tertiary amine compounds such as tri (n-butyl) amine, tetramethylethylenediamine, 1-methylpiperidine, 1-methylpyrrolidine, 4-dimethylaminopyridine, triethylenediamine, bisdimethylaminoethyl ether, triisopropanolamine, etc. Grade amines,
These industrial products include Lion's Armin (DMMCD, DMTD, DMMHTD, DM12D, DM14D, DM16D, DM18D, DM22D, M2HT, M2O, M210D), Kao's Farmin (DM24C, DM0898, DM1098, DM2098, DM2465, DM2463) DM2458, DM4098, DM4662, DM6098, DM6875, DM8680, DM8098, DM2285, M2-2095, T-08) and the like;
(4) Alkanolamine Kao Aminone (PK-02S, L-02), etc .;
(5) Modified amine (5-1) Alkylamine Ethylene oxide adduct Lion Esomin (C / 12, C / 15, C / 25, T / 12, T / 15, T / 25, S / 15, S / 25, O / 12, O / 17, O / 20, HT / 12, HT / 14, HT / 17), Lion esomide (HT / 15, HT / 60, O / 15), Asahi Denka Kogyo Co., Ltd. Made Adekasol (CO, COA, CMA, YA-6), Kao Amit (105,320);
However, it is not limited to these.

  These fatty acids and amine compounds may be used either alone or in combination of two or more.

  When using a fatty acid or an amine compound, it is preferably contained in an amount that occupies 0.1 to 10 parts by weight with respect to 100 parts by weight of the solid curing catalyst contained in the water-dispersed curing catalyst (c). More preferably, it is ˜7 parts by weight.

  By adding these fatty acids or amine compounds to the electrodeposition coating composition (c), there is an effect that the dispersibility of the solid curing catalyst is remarkably improved.

  The water-dispersed curing catalyst (c) used in the present invention is characterized by extremely excellent dispersion stability. The solid curing catalyst generally has poor dispersibility, and when the solid curing catalyst is dispersed together with the pigment, there is a problem due to the dispersibility of the solid curing catalyst and the pigment being different. That is, when preparing a paste by dispersing a solid curing catalyst together with a pigment, if the dispersion is terminated when the pigment is dispersed, the solid curing catalyst is not sufficiently dispersed and the solid curing catalyst settles with time. was there. On the other hand, when the dispersion is finished when the solid curing catalyst is sufficiently dispersed, the pigment is overdispersed, the resulting paste is thickened, and a large amount of paste is prepared over a long period of time. There were disadvantages such as preparation costs.

  These problems can be solved by using the water-dispersed curing catalyst (c). By using this water-dispersed curing catalyst (c) for the preparation of the cationic electrodeposition coating composition, it is possible to disperse the pigment and the solid curing catalyst under optimum conditions according to their dispersibility. Therefore, it is possible to prepare a cationic electrodeposition coating composition without problems such as precipitation of the solid curing catalyst, thickening of the pigment paste, and deterioration of the coating appearance derived therefrom. In addition, since the dispersion can be performed under optimum conditions according to the solid curing catalyst and the pigment paste, the preparation time of the pigment dispersion paste and the water-dispersed curing catalyst (c) is advantageously reduced as a result. Further, this water-dispersed curing catalyst (c) is very excellent in dispersion stability, and the water-dispersed curing catalyst (c) itself can be left as it is without stirring. Further, a pigment dispersion paste is prepared using a pigment and a pigment dispersion resin, and then the obtained pigment dispersion paste and the water dispersion type curing catalyst (c) are mixed, or the water dispersion type curing catalyst (c) and Even when the binder resin emulsion is mixed in advance, the dispersion stability is excellent and there is an advantage that the solid curing catalyst does not precipitate. Further, there is an advantage that the solid curing catalyst does not precipitate even when the water-dispersed curing catalyst (c) is added to the electrodeposition coating composition. For this reason, there exists an advantage that preparation of a cationic electrodeposition coating composition becomes easier.

  Moreover, the cured electrodeposition coating film obtained by the cationic electrodeposition coating composition containing the water-dispersed curing catalyst (c) also has an advantage that the coating film appearance is excellent. Since the water-dispersed curing catalyst (c) has very excellent dispersion stability, the use of the water-dispersed curing catalyst (c) makes it possible to uniformly form a solid curing catalyst in the cationic electrodeposition coating composition. Can be dispersed. By uniformly dispersing the solid curing catalyst in this way, a cured electrodeposition coating film having an excellent coating film appearance can be obtained without the solid curing catalyst reaggregating.

Amine-modified epoxy resin (a)
As the amine-modified epoxy resin (a), an epoxy resin modified with an amine generally used in an electrodeposition coating composition can be used without particular limitation. As the amine-modified epoxy resin (a), amine-modified epoxy resins (a) known to those skilled in the art and those obtained by amine-modifying commercially available epoxy resins can be used.

  A preferred amine-modified epoxy resin (a) is an amine-modified epoxy resin (a) obtained by modifying an oxirane ring in a resin skeleton with an organic amine compound. In general, the amine-modified epoxy resin (a) is produced by opening the oxirane ring in the starting material resin molecule by reaction with amines such as primary amine, secondary amine or tertiary amine and / or its acid salt. Is done. A typical example of the starting material resin is a polyphenol polyglycidyl ether type epoxy resin which is a reaction product of a polycyclic phenol compound such as bisphenol A, bisphenol F, bisphenol S, phenol novolak, cresol novolak and epichlorohydrin. Examples of other starting material resins include oxazolidone ring-containing epoxy resins described in JP-A-5-306327 and known. These epoxy resins are obtained by a reaction between a diisocyanate compound or a bisurethane compound obtained by blocking an NCO group of a diisocyanate compound with a lower alcohol such as methanol or ethanol, and epichlorohydrin.

  The starting material resin is used by extending the chain with a bifunctional polyester polyol, polyether polyol, bisphenol, dibasic carboxylic acid or the like, if necessary, before the oxirane ring-opening reaction with amines. be able to.

  In addition, prior to the oxirane ring-opening reaction with amines, 2-ethylhexanol, nonylphenol, ethylene glycol mono- acrylate for some oxirane rings for the purpose of adjusting molecular weight or amine equivalent, improving heat flow, etc. Monohydroxy compounds such as 2-ethylhexyl ether, ethylene glycol mono-n-butyl ether, propylene glycol mono-2-ethylhexyl ether can be added and used.

  Examples of amines that can be used for opening an oxirane ring and introducing an amino group include butylamine, octylamine, diethylamine, dibutylamine, methylbutylamine, monoethanolamine, diethanolamine, N-methylethanolamine , N-ethylethanolamine, triethylamine, N, N-dimethylbenzylamine, primary amines such as N, N-dimethylethanolamine, secondary amines or tertiary amines and / or their acid salts. Further, ketimine block primary amino group-containing secondary amine such as aminoethylethanolamine methyl isobutyl ketimine, diethylenetriamine diketimine can also be used. These amines must be reacted with at least an equivalent amount relative to the oxirane ring in order to open all the oxirane rings.

  The number average molecular weight of the amine-modified epoxy resin (a) is preferably in the range of 1,500 to 5,000, and more preferably in the range of 1,600 to 3,000. When the number average molecular weight is less than 1,500, physical properties such as solvent resistance and corrosion resistance of the cured coating film may be inferior. If it exceeds 5,000, the viscosity of the resin solution may be difficult to control and synthesis may be difficult, and handling such as emulsification and dispersion of the resulting resin may be difficult to handle. Furthermore, because of its high viscosity, the flowability during heating and curing is poor, and the appearance of the coating film may be impaired.

  The amine-modified epoxy resin (a) is preferably molecularly designed so that the hydroxyl value is in the range of 50 to 200 mmol / 100 g. If the hydroxyl value is less than 50 mmol / 100 g, poor curing of the coating may be caused. When the hydroxyl value exceeds 250 mmol / 100 g, excessive hydroxyl groups remain in the coating film after curing, and as a result, water resistance may decrease.

  The amine-modified epoxy resin (a) is preferably molecularly designed so that the amine value is in the range of 40 to 150 mmol / 100 g. If the amine value is less than 40 mmol / 100 g, the emulsification dispersion failure in the aqueous medium due to the acid treatment described in detail below will be caused. Conversely, if the amine value exceeds 150 mmol / 100 g, excess amino groups will remain in the coating film after curing. The water resistance may decrease.

Block isocyanate curing agent (b)
The cationic electrodeposition coating composition contains a blocked isocyanate curing agent (b) obtained by blocking polyisocyanate with a blocking agent. Here, the polyisocyanate means a compound having two or more isocyanate groups in one molecule. The polyisocyanate may be, for example, any of aliphatic, alicyclic, aromatic and aromatic-aliphatic.

  Specific examples of polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), p-phenylene diisocyanate, and naphthalene diisocyanate; hexamethylene diisocyanate (HDI), 2,2,4- C3-C12 aliphatic diisocyanates such as trimethylhexane diisocyanate and lysine diisocyanate; 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) , Methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, and 1,3-diisocyanatomethylcyclo Carbon such as xane (hydrogenated XDI), hydrogenated TDI, 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane (also referred to as norbornane diisocyanate). Aliphatic diisocyanates having a number of 5 to 18; aliphatic diisocyanates having an aromatic ring such as xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI); modified products of these diisocyanates (urethanes, carbodiimides, Uretdione, uretoimine, burette and / or isocyanurate modified product); and the like. These may be used alone or in combination of two or more.

  Adducts or prepolymers obtained by reacting polyisocyanates with polyhydric alcohols such as ethylene glycol, propylene glycol, trimethylolpropane and hexanetriol at an NCO / OH ratio of 2 or more are also used as the block isocyanate curing agent (b). Good.

  Preferred specific examples of the aliphatic polyisocyanate or alicyclic polyisocyanate include hexamethylene diisocyanate, hydrogenated TDI, hydrogenated MDI, hydrogenated XDI, IPDI, norbornane diisocyanate, dimer (biuret) and trimer thereof. (Isocyanurate) etc. are mentioned.

  The blocking agent is added to a polyisocyanate group and is stable at ordinary temperature, but can regenerate a free isocyanate group when heated to a temperature higher than the dissociation temperature.

  As a blocking agent, when low temperature curing (160 ° C. or lower) is desired, lactam blocking agents such as ε-caprolactam, δ-valerolactam, γ-butyrolactam and β-propiolactam, and formaldoxime, acetoald It is preferable to use an oxime blocking agent such as oxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, and cyclohexane oxime.

Pigment The cationic electrodeposition coating composition of the present invention may contain a commonly used pigment. Examples of pigments that can be used include coloring pigments such as titanium oxide, carbon black, iron oxide and bengara, extender pigments such as kaolin, talc, aluminum silicate, calcium carbonate, mica, clay and silica, phosphorus Zinc oxide, iron phosphate, aluminum phosphate, calcium phosphate, zinc phosphite, zinc cyanide, zinc oxide, aluminum tripolyphosphate, zinc molybdate, aluminum molybdate, calcium molybdate, aluminum phosphomolybdate, aluminum phosphomolybdate Examples include rust preventive pigments such as zinc.

  In general, the pigment is preferably contained in the cationic electrodeposition coating composition in an amount that occupies a lower limit of 1% by weight and an upper limit of 60% by weight with respect to the total solid content of the cationic electrodeposition coating composition. The upper limit is more preferably 30% by weight.

Pigment-dispersed paste When the pigment is used as a component of an electrodeposition paint, it is preferable to disperse the pigment together with a resin called a pigment-dispersed resin in an aqueous solvent at a high concentration in advance to form a paste. This is because the pigment is in a powder form, and it is difficult to disperse in a single step in a low concentration uniform state used in the electrodeposition coating composition. Such a paste is called a pigment dispersion paste. A pigment dispersion paste generally includes a pigment and a pigment dispersion resin.

  The pigment dispersion paste is prepared by dispersing a pigment together with a pigment dispersion resin in an aqueous solvent. As the pigment dispersion resin, a cationic polymer such as a cationic or nonionic low molecular weight surfactant or a modified epoxy resin having a quaternary ammonium group and / or a tertiary sulfonium group is generally used. As the aqueous solvent, ion-exchanged water or water containing a small amount of alcohol is used. In general, the pigment dispersion resin is used in an amount of 20 to 100 parts by weight based on 100 parts by weight of the pigment. After the pigment dispersion resin and the pigment are mixed, the pigment is dispersed using a normal dispersing device such as a ball mill or a sand grind mill until the pigment in the mixture has a predetermined uniform particle size. A paste can be obtained.

Other Components The cationic electrodeposition paint of the present invention can contain conventional paint additives such as an antifoaming agent, a water-miscible organic solvent, an antioxidant, and an ultraviolet absorber, if necessary.

Preparation of cationic electrodeposition coating composition The cationic electrodeposition coating composition of the present invention comprises an amine-modified epoxy resin (a) and a blocked isocyanate curing agent (b) dispersed in an aqueous solvent (binder resin emulsion) It can be prepared by mixing ionic water, a water-dispersed curing catalyst (c), and, if necessary, a pigment-dispersed paste at a predetermined ratio.

  Conventionally, when preparing an electrodeposition coating composition containing a solid curing catalyst, the solid curing catalyst is generally dispersed together with the pigment when preparing the pigment dispersion paste. Problems that may occur in this case are as described above. On the other hand, since the water-dispersed curing catalyst (c) of the present invention is very excellent in dispersion stability, it can be added and mixed by various methods in the preparation of the cationic electrodeposition coating composition. For example, when mixing the binder resin emulsion and the pigment dispersion paste, the water dispersion type curing catalyst (c) may be added and mixed together. Alternatively, the water dispersion type curing catalyst (c) may be added in advance to the binder resin emulsion, and the water dispersion type curing catalyst (c) may be added in advance to the pigment dispersion paste.

  In addition, fatty acids or amine compounds that are preferably used in the preparation of the water-dispersed curing catalyst (c) of the present invention may be added to the electrodeposition coating composition. In this case, fatty acids or amine compounds can be added in any dispersion / mixing stage. Fatty acids or amine compounds are preferably added to the above-mentioned cationic pigment dispersion paste and then mixed with other components such as a cationic main emulsion. In this case, it is because it is excellent in the performance which prevents sedimentation of a pigment. By adding fatty acids or amine compounds to the electrodeposition coating composition, there is little precipitate even when the electrodeposition coating composition is allowed to stand for a long time without stirring, and stirring required during coating It is possible to obtain a merit that costs such as energy and stirring equipment costs are not required. Although the mechanism of action by which the dispersibility of the pigment is improved by adding a fatty acid or an amine compound to the electrodeposition coating composition is not clear, for example, a structure in which the fatty acid is a monomolecular film or a bimolecular film with respect to the pigment It is considered that this arrangement increases the resistance of the pigment to water and prevents the pigment from settling. The fatty acids or amine compounds used in the present invention have a high ability to be arranged in a structure such as a molecular film, and are excellent in the performance of preventing the precipitation of the pigment.

  As the aqueous solvent used in the cationic electrodeposition coating composition, ion-exchanged water, pure water or the like can be used. The aqueous solvent may contain a small amount of alcohols as required. The aqueous solvent contains a neutralizing agent in order to improve the dispersibility of the amine-modified epoxy resin (a). Neutralizing agents are inorganic or organic acids such as hydrochloric acid, nitric acid, phosphoric acid, formic acid, acetic acid, lactic acid. The amount is that which achieves a neutralization rate of at least 20%, preferably 30-60%.

  The amount of the blocked isocyanate curing agent (b) reacts with an active hydrogen-containing functional group such as a primary, secondary or / and tertiary amino group or a hydroxyl group in the amine-modified epoxy resin (a) at the time of curing and is cured well. It must be sufficient to give a coating, generally 90/10 to 50/50, preferably 80/20 to the weight ratio of amine-modified epoxy resin (a) to blocked isocyanate curing agent (b). The range is 65/35. The binder resin containing the amine-modified epoxy resin (a) and the blocked isocyanate curing agent (b) generally accounts for 25 to 85% by weight, preferably 40 to 70% by weight of the total solid content of the electrodeposition coating composition. And contained in the electrodeposition coating composition.

  When the cationic electrodeposition coating composition of the present invention is a low solid content type cationic electrodeposition coating composition, the solid content concentration of the coating composition is smaller than the conventional 20% by weight. The partial concentration is preferably 0.5 to 9% by weight, more preferably 3 to 9% by weight. Such a low solid content type cationic electrodeposition coating composition has an advantage that there is little sediment when left standing, and therefore there is little energy cost for stirring and circulation. By using the water-dispersed curing catalyst (c) in such a low solid content type cationic electrodeposition coating composition, a solid curing catalyst having poor dispersibility can be well dispersed, and thereby a low solid content type catalyst can be dispersed. There is an advantage that the sedimentation stability of the cationic electrodeposition coating composition can be further improved. Further, the use of the water-dispersed curing catalyst (c) in the low solid content type cationic electrodeposition coating composition has an advantage that the pigment concentration can be easily designed. In addition, in the low solid content type cationic electrodeposition coating composition, when the solid content concentration is less than 0.5% by weight, the conductivity of the electrodeposition coating composition is lowered, and the deposition property of the electrodeposition coating film is lowered. There is a fear. On the other hand, the solid concentration may exceed 9% by weight, but in this case, it is not classified as a low solid content type cationic electrodeposition coating composition, and the energy cost for stirring and circulation of the electrodeposition tank is reduced. It is difficult.

Electrodeposition Coating The electrodeposition coating composition of the present invention can be electrodeposited onto an article to be coated by a method well known to those skilled in the art, whereby a cured electrodeposition coating film can be obtained. The object to be coated when the electrodeposition coating is performed using the cationic electrodeposition coating composition of the present invention is preferably previously subjected to a surface treatment such as a chemical conversion treatment. Examples of the object to be coated include cold-rolled steel sheet, hot-rolled steel sheet, stainless steel, electrogalvanized steel sheet, hot-dip galvanized steel sheet, zinc-aluminum alloy-based steel sheet, zinc-iron alloy-based steel sheet, zinc-magnesium alloy-based steel sheet. Steel materials such as zinc-aluminum-magnesium alloy plated steel plate, aluminum-based plated steel plate, aluminum-silicon alloy-plated steel plate, tin-based plated steel plate, lead-tin alloy-plated steel plate, chromium-based plated steel plate, and these steel plates Steel material that has been subjected to chemical conversion treatment, and the like.

  In electrodeposition coating, an uncured electrodeposition coating film is formed by immersing an object to be coated in a cationic electrodeposition coating composition as a cathode and then applying a voltage between the anode and depositing a film. The The time for applying the voltage varies depending on the electrodeposition conditions, but can generally be 2 to 4 minutes.

  The film thickness of the electrodeposition coating film is preferably 5 to 25 μm as a dry film thickness, and more preferably about 20 μm. If the film thickness is less than 5 μm, the rust prevention property may be insufficient, and if it exceeds 25 μm, the paint may be wasted.

  The electrodeposition coating film obtained as described above is cured or electrodeposited by baking at 120 to 260 ° C., preferably 140 to 220 ° C. for 10 to 30 minutes after completion of the electrodeposition process or after washing with water. A coating film is formed.

Replenishment Cationic Electrodeposition Coating Composition The present invention further provides a replenishment cationic electrodeposition coating composition. Electrodeposition coating using a cationic electrodeposition coating composition is performed by immersing an object to be coated as a cathode in an electrodeposition tank containing the cationic electrodeposition coating composition, and applying a voltage to the electrodeposition on the object to be coated. This is done by depositing a coating film. Thus, electrodeposition coating is a coating method by precipitating a solid content from a cationic electrodeposition coating composition. Therefore, by performing electrodeposition coating, the coating solid content of the electrodeposition coating composition in the electrodeposition tank and The pigment concentration is decreasing. In this case, the replenishment cationic electrodeposition coating composition having a higher solid content and higher pigment concentration than the cationic electrodeposition coating composition used for electrodeposition coating is replenished to the electrodeposition tank. The reduced coating solids and pigment concentration of the electrodeposition coating composition therein can be adjusted to an appropriate range.

  A binder resin emulsion in which an amine-modified epoxy resin (a) and a blocked isocyanate curing agent (b) are dispersed in an aqueous solvent as a method for adjusting the paint solid content and pigment concentration reduced by electrodeposition coating to an appropriate range; In general, replenishment is performed using two types of solutions, a pigment dispersion paste in which a pigment is dispersed in an aqueous solvent. This is because if the binder resin emulsion and the pigment dispersion paste are mixed in advance, precipitation of a solid catalyst and a pigment having poor dispersibility occurs.

  Thus, the said water dispersion type curing catalyst (c) can be used for preparation of the replenishment cationic electrodeposition coating composition used for supplying an electrodeposition coating composition to an electrodeposition tank. As such a replenishment cationic electrodeposition coating composition, for example, it comprises a binder resin emulsion liquid (first liquid) containing the water-dispersed curing catalyst (c), and a pigment-dispersed paste liquid (second liquid). A two-component replenishment cationic electrodeposition coating composition may be mentioned. The water-dispersed curing catalyst (c) used in the present invention is very excellent in dispersion stability, and even in such a two-component replenishment cationic electrodeposition coating composition, the solid catalyst does not precipitate and is stable in dispersion. It is possible to prepare a two-component replenishment cationic electrodeposition coating composition having excellent properties.

  Such a two-component replenishment cationic electrodeposition coating composition is prepared using the water-dispersed curing catalyst (c) and the binder resin emulsion and pigment dispersion paste used for the preparation of the cationic electrodeposition coating composition. be able to. The binder resin emulsion liquid (first liquid) can be prepared by mixing the water-dispersed curing catalyst (c) and the binder resin emulsion, and the pigment dispersion paste liquid (second liquid) It can be used as it is or diluted as necessary. In the two-component replenishment cationic electrodeposition coating composition, the binder solid emulsion liquid (first liquid) containing the water-dispersed curing catalyst (c) preferably has a coating solid content concentration of 20 to 60% by weight, 30 More preferred is ˜50% by weight. The pigment concentration of the pigment dispersion paste liquid (second liquid) of the two-component replenishment cationic electrodeposition coating composition is preferably 20 to 60% by weight based on the total solid content.

  In addition to the above, as a two-component replenishment cationic electrodeposition coating composition, a two-component replenishment cation comprising a solution prepared by previously mixing a pigment dispersion paste and a water-dispersed curing catalyst (c), and a binder resin emulsion. An electrodeposition coating composition can be used. Furthermore, a three-component replenishment cationic electrodeposition coating composition in which the binder resin emulsion, the water-dispersed curing catalyst (c), and the pigment dispersion paste are dispersed in separate solutions can also be used. Since the water-dispersed curing catalyst (c) in the present invention is very excellent in dispersion stability, it can be used in various forms. By using such a two-component or three-component replenishment cationic electrodeposition coating composition, there is an advantage that an electrodeposition coating composition can be prepared according to various objects to be coated and the purpose of coating.

  By the way, such a paint replenishing method using two kinds of solutions is disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-126789. In this paint replenishment method, as described in JP-A-2005-126789, when the binder resin emulsion and the pigment dispersion paste stored in the oil can or the drum can are replenished by adjusting the ratio of the number of cans, respectively. There is. In this case, it is difficult to finely control the solid content of the paint and the pigment concentration in the electrodeposition tank (for example, control in units of 0.1% by weight) with the conventional replenishment method. In addition, it is troublesome and complicated to mix and replenish these binder resin emulsion and pigment dispersion paste each time it is replenished. Furthermore, it is necessary to secure a space for storing these replenishing paints, and a larger storage space is required by including the binder resin emulsion and the pigment dispersion paste in separate oil cans or drums. There was also a problem.

  Such a problem can also be solved by preparing a one-component replenishment cationic electrodeposition coating composition using the water-dispersed curing catalyst (c). The water-dispersed curing catalyst (c) is characterized by being very excellent in dispersion stability. Since the one-component replenishment cationic electrodeposition coating composition prepared using this water-dispersed curing catalyst (c) is excellent in dispersion stability, a binder resin emulsion, a pigment-dispersed paste, and a water-dispersed curing catalyst (c) Even if they are mixed in advance, the solid catalyst does not precipitate. By using the water-dispersed curing catalyst (c) in the present invention, it is possible to prepare a replenishment cationic electrodeposition coating composition that is a so-called one-pack type and excellent in dispersion stability. This one-component replenishment cationic electrodeposition coating composition is excellent in dispersion stability even if it is a one-component type, and can be stored for a long time. The one-component replenishment cationic electrodeposition coating composition of the present invention further solves the problems associated with the two-component replenishing coating, such as the complexity of replenishment and the storage space for the replenishing coating. be able to.

  The replenishing cationic electrodeposition coating composition can be prepared using the water-dispersed curing catalyst (c), and the binder resin emulsion and pigment dispersion paste used for the preparation of the cationic electrodeposition coating composition. . The replenishing cationic electrodeposition coating composition preferably has a coating solid content concentration of 20 to 60% by weight, more preferably 30 to 50% by weight. The pigment concentration of the replenishing cationic electrodeposition coating composition is contained in the cationic electrodeposition coating composition in an amount that occupies a lower limit of 0.5% by weight and an upper limit of 60% by weight with respect to the total solid content of the coating composition. The upper limit is more preferably 30% by weight.

  The following examples further illustrate the present invention, but the present invention is not limited thereto. In the examples, “parts” and “%” are based on weight unless otherwise specified.

Production Example 1 Preparation of amine-modified epoxy resin (a) To a flask equipped with a stirrer, a condenser tube, a nitrogen inlet tube, a thermometer and a dropping funnel, 2,4- / 2,6-tolylene diisocyanate (weight ratio = 8 / 2) 92 parts, 95 parts of methyl isobutyl ketone (hereinafter abbreviated as MIBK) and 0.5 part of dibutyltin dilaurate were charged. While stirring the reaction mixture, 21 parts of methanol was added dropwise. The reaction was started from room temperature and heated to 60 ° C. due to heat generation. Then, after continuing reaction for 30 minutes, 50 parts of ethylene glycol mono-2-ethylhexyl ether was dripped from the dropping funnel. Further, 53 parts of a bisphenol A-propylene oxide 5 mol adduct was added to the reaction mixture. The reaction was mainly carried out in the range of 60 to 65 ° C. and continued until absorption based on the isocyanate group disappeared in the measurement of IR spectrum.

  Next, 365 parts of epoxy resin with an epoxy equivalent of 188 synthesized from bisphenol A and epichlorohydrin by a known method was added to the reaction mixture, and the temperature was raised to 125 ° C. Thereafter, 1.0 part of benzyldimethylamine was added and reacted at 130 ° C. until the epoxy equivalent was 410.

  Subsequently, 61 parts of bisphenol A and 33 parts of octylic acid were added and reacted at 120 ° C., resulting in an epoxy equivalent of 1190. Thereafter, the reaction mixture was cooled, 11 parts of diethanolamine, 24 parts of N-ethylethanolamine and 25 parts of 79 wt% MIBK solution of ketimine product of aminoethylethanolamine were added and reacted at 110 ° C. for 2 hours. Then, it diluted with MIBK until it became non-volatile content 80%, and amine-modified epoxy resin (a) (resin solid content 80%) was obtained.

Production Example 2 Preparation of Blocked Isocyanate Curing Agent (b) 1250 parts of diphenylmethane diisocyanate and 266.4 parts of MIBK were charged into a reaction vessel and heated to 80 ° C., and then 2.5 parts of dibutyltin dilaurate was added. A solution prepared by dissolving 226 parts of ε-caprolactam in 944 parts of butyl cellosolve was added dropwise at 80 ° C. over 2 hours. Further, after heating at 100 ° C. for 4 hours, in the measurement of IR spectrum, it was confirmed that the absorption based on the isocyanate group had disappeared, and after cooling, 336.1 parts of MIBK was added to obtain a blocked isocyanate curing agent (b). It was.

Production Example 3 Preparation of Pigment Dispersing Resin First, 222.0 parts of isophorone diisocyanate (hereinafter abbreviated as IPDI) was placed in a reaction vessel equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe and a thermometer. After dilution, 0.2 part of heredibutyltin dilaurate was added. Then, after heating this to 50 degreeC, 131.5 parts of 2-ethylhexanol was dripped over 2 hours in dry nitrogen atmosphere, stirring. The reaction temperature was maintained at 50 ° C. by cooling appropriately. As a result, 2-ethylhexanol half-blocked IPDI (resin solid content: 90.0%) was obtained.

  Next, 87.2 parts of dimethylethanolamine, 117.6 parts of 75% aqueous lactic acid solution, and 39.2 parts of ethylene glycol monobutyl ether are added to a suitable reaction vessel in this order, and the mixture is stirred at 65 ° C. for about half an hour to form quaternization. An agent was prepared.

  Next, 710.0 parts of EPON 829 (bisphenol A type epoxy resin manufactured by Shell Chemical Company, epoxy equivalent of 193 to 203) and 289.6 parts of bisphenol A were charged into a suitable reaction vessel, and the reaction was conducted under a nitrogen atmosphere. When heated to 150-160 ° C., an initial exothermic reaction occurred. The reaction mixture was reacted at 150-160 ° C. for about 1 hour, then cooled to 120 ° C., and 498.8 parts of 2-ethylhexanol half-blocked IPDI (MIBK solution) prepared above was added.

  The reaction mixture is kept at 110-120 ° C. for about 1 hour, then 463.4 parts of ethylene glycol monobutyl ether are added, the mixture is cooled to 85-95 ° C. and homogenized, and then the quaternizing agent 196 prepared above is used. 7 parts were added. After maintaining the reaction mixture at 85 to 95 ° C. until the acid value becomes 1, 964 parts of deionized water is added to finish quaternization in the epoxy-bisphenol A resin, and a pigment dispersion having a quaternary ammonium salt portion Resin was obtained (resin solid content 50%).

Production Example 4 Preparation of Pigment Dispersion Paste Into a sand grind mill, 100 parts of the pigment dispersion resin obtained in Production Example 3, 59.2 parts of titanium dioxide, 1.9 parts of carbon black, 38.9 parts of kaolin and ion-exchanged water 100.0 parts was added and dispersed until the particle size became 10 μm or less to obtain a pigment dispersion paste (solid content 50%). The time required for dispersion was 1 hour.

Production Example 5 Preparation of Binder Resin Emulsion The amine-modified epoxy resin (a) obtained in Production Example 1 and the blocked isocyanate curing agent (b) obtained in Production Example 2 are uniform at a solid content ratio of 80/20. Mixed. Glacial acetic acid was added so that the milligram equivalent (MEQ (A)) of the acid per 100 g of resin solids was 30, and ion-exchanged water was slowly added to dilute. By removing MIBK under reduced pressure, an emulsion having a solid content of 36% was obtained.

Production Example 6 Preparation of Water Dispersion Type Curing Catalyst (c-1) As a solid curing catalyst, bismuth hydroxide (fine particles having an average particle size of 15 μm) was used. 25 parts by weight of bismuth hydroxide, 25 parts by weight of a nonionic surfactant (TG-740W, manufactured by Kyoeisha Chemical Co., Ltd.), 1 part by weight of heptanoic acid as a fatty acid, and 49 parts by weight of ion-exchanged water were placed in a grind mill. . In this grind mill, 0.8 mm diameter zircon beads were put and dispersed for 1 hour. In the obtained water-dispersed curing catalyst (c-1), the amount of the nonionic surfactant relative to 100 parts by weight of the solid curing catalyst was 100 parts by weight, and the average particle size was 160 nm. In this specification, the average particle size of the obtained water-dispersed curing catalyst (c) is a value (volume average particle size) measured by a laser light scattering method using Microtrac UPA (manufactured by Nikkiso Co., Ltd.). It is. The viscosity of the water-dispersed curing catalyst (c-1) was 45 KU or less. In this specification, the viscosity was measured using a Stormer viscometer.

Production Example 7 Preparation of water-dispersed curing catalyst (c-2) Dibutyltin oxide (fine particles having an average particle size of 5 μm) was used as a solid curing catalyst. Grinding 25 parts by weight of dibutyltin oxide, 2.5 parts by weight of nonionic surfactant (TG-740W, manufactured by Kyoeisha Chemical Co., Ltd.), 1 part by weight of heptanoic acid as fatty acids, and 26.5 parts by weight of ion-exchanged water. Put in the mill. In this grind mill, 0.8 mm diameter zircon beads were put and dispersed for 1 hour. In the obtained water-dispersed curing catalyst (c-2), the amount of the nonionic surfactant with respect to 100 parts by weight of the solid curing catalyst was 10 parts by weight, and the average particle size was 150 nm. The viscosity of the water-dispersed curing catalyst (c-2) was 45 KU or less.

Production Example 8 Preparation of Water Dispersion Type Curing Catalyst (c-3) Monobutyltin oxide (fine particles having an average particle size of 15 μm) was used as the solid curing catalyst. 25 parts by weight of monobutyltin oxide, 25 parts by weight of nonionic surfactant (TG-740W, manufactured by Kyoeisha Chemical Co., Ltd.), 1 part by weight of heptanoic acid as fatty acids, and 49 parts by weight of ion-exchanged water were placed in a grind mill. . In this grind mill, 0.8 mm diameter zircon beads were put and dispersed for 1 hour. In the obtained water-dispersed curing catalyst (c-3), the amount of the nonionic surfactant relative to 100 parts by weight of the solid curing catalyst was 100 parts by weight, and the average particle size was 160 nm. The viscosity of the water-dispersed curing catalyst (c-3) was 45 KU or less.

Production Example 9 Preparation of Water Dispersion Type Curing Catalyst (c-4) As a solid curing catalyst, bismuth hydroxide (fine particles having an average particle size of 15 μm) was used. 25 parts by weight of bismuth hydroxide, 25 parts by weight of a nonionic surfactant (TG-740W, manufactured by Kyoeisha Chemical Co., Ltd.) and 50 parts by weight of ion-exchanged water were placed in a grind mill. In this grind mill, 0.8 mm diameter zircon beads were put and dispersed for 1 hour. In the obtained water-dispersed curing catalyst (c-4), the amount of the nonionic surfactant relative to 100 parts by weight of the solid curing catalyst was 100 parts by weight, and the average particle size was 190 nm. The viscosity of the water-dispersed curing catalyst (c-4) was 47 KU.

Comparative Production Example 1 Preparation of water-dispersed curing catalyst (c-5) (liquid curing catalyst dispersion) Dibutyltin laurate was used as a liquid curing catalyst. 25 parts by weight of dibutyltin laurate, 25 parts by weight of a nonionic surfactant (TG-740W, manufactured by Kyoeisha Chemical Co., Ltd.) and 1 part by weight of heptanoic acid as fatty acids were mixed until uniform. To this, 49 parts by weight of ion exchange water was slowly added. In the obtained water-dispersed curing catalyst (c-5), the amount of the nonionic surfactant relative to 100 parts by weight of the liquid curing catalyst was 100 parts by weight, and the average particle size was 120 nm. The viscosity of the water-dispersed curing catalyst (c-5) was 45 KU or less.

Comparative Production Example 2 Preparation of Water Dispersion Type Curing Catalyst (c-6) Dibutyltin oxide (fine particles having an average particle size of 5 μm) was used as the solid curing catalyst. 25 parts by weight of dibutyltin oxide, 25 parts by weight of the pigment-dispersed resin obtained from Production Example 3, and 50 parts by weight of ion-exchanged water were placed in a grind mill. In this grind mill, 0.8 mm diameter zircon beads were put and dispersed for 1 hour. The average particle size of the obtained water-dispersed curing catalyst (c-6) was 250 nm. The viscosity of the water-dispersed curing catalyst (c-6) was 49 KU.

Example 1
Preparation of cationic electrodeposition coating composition 158 parts of binder resin emulsion obtained in Production Example 5 and 8 parts of pigment dispersion paste obtained in Production Example 4, 144 parts of ion-exchanged water and water-dispersed curing of Production Example 6 Catalyst (c-1) 3.5 parts was mixed to obtain a cationic electrodeposition coating composition having a coating solid content of 20% by weight. The pigment concentration of the cationic electrodeposition coating composition was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight. The solid content of the paint can be determined as a percentage of the weight of the residue after heating at 180 ° C. for 30 minutes (according to JIS K5601).

Example 2
Example 1 with the exception of using 1.9 parts of the water-dispersed curing catalyst (c-2) of Production Example 7 instead of 3.5 parts of the water-dispersed curing catalyst (c-1) of Production Example 6 Similarly, a cationic electrodeposition coating composition was prepared. The coating solid content of the cationic electrodeposition coating composition was 20% by weight, and the pigment concentration was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight.

Example 3
2. 158 parts of the binder resin emulsion obtained in Production Example 5 and 8 parts of the pigment dispersion paste obtained in Production Example 4, 831 parts of ion-exchanged water, and the water-dispersed curing catalyst (c-1) of Production Example 8. 5 parts was mixed to obtain a cationic electrodeposition coating composition having a coating solid content of 6% by weight. The pigment concentration of the cationic electrodeposition coating composition was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight.

Example 4
Example 1 except that 3.5 parts of the water-dispersed curing catalyst (c-1) of Production Example 6 is used instead of 3.5 parts of the water-dispersed curing catalyst (c-4) of Production Example 9. Similarly, a cationic electrodeposition coating composition was prepared. The coating solid content of the cationic electrodeposition coating composition was 20% by weight, and the pigment concentration was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight.

Comparative Example 1
Example 1 except that 3.5 parts of the water-dispersed curing catalyst (c-1) of Production Example 6 is used instead of 3.5 parts of the water-dispersed curing catalyst (c-5) of Comparative Production Example 1. In the same manner as above, a cationic electrodeposition coating composition was prepared. The coating solid content of the cationic electrodeposition coating composition was 20% by weight, and the pigment concentration was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight.

Comparative Example 2
Example 1 except that 3.5 parts of the water-dispersed curing catalyst (c-1) of Production Example 6 is used instead of 3.5 parts of the water-dispersed curing catalyst (c-6) of Comparative Production Example 2. In the same manner as above, a cationic electrodeposition coating composition was prepared. The coating solid content of the cationic electrodeposition coating composition was 20% by weight, and the pigment concentration was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight.

Comparative Example 3
Preparation of Pigment Dispersion Paste Containing Solid Curing Catalyst 100 parts of pigment dispersing resin obtained in Production Example 3, 41.2 parts of titanium dioxide, 1.32 parts of carbon black, 27.1 parts of kaolin, dibutyl 30.4 parts of tin oxide and 100.0 parts of ion-exchanged water were added and dispersed until the particle size became 10 μm or less to obtain a pigment dispersion paste (solid content 50%). The time required for dispersion was 3 hours.

  A cationic electrodeposition coating composition was prepared in the same manner as in Example 1 except that 11.5 parts of the obtained pigment dispersion paste was used instead of 8 parts of the pigment dispersion paste of Production Example 4. The coating solid content of the cationic electrodeposition coating composition was 20% by weight, and the pigment concentration was 3% by weight. Further, the content of the solid curing catalyst with respect to 100 parts by weight of the resin solid content of the cationic electrodeposition coating composition was 1.5 parts by weight.

  The following evaluation tests were performed on the water-dispersed curing catalyst (c) used for the preparation of the cationic electrodeposition coating composition and the cationic electrodeposition coating composition obtained in the above examples and comparative examples.

Dispersion stability The dispersion stability was evaluated by allowing the water-dispersed curing catalyst (c) used in each Example and Comparative Example to stand at 40 ° C for a certain period. The evaluation criteria are as follows.
A: No precipitation even after standing for 4 weeks or more.
○: Precipitation occurs after standing for about 3 weeks.
Δ: Precipitation occurs after standing for about 2 weeks.
X: Precipitation occurs after standing for about 1 week.

Appearance evaluation of cured electrodeposition coating film The cation galvanized coating compositions of Examples and Comparative Examples were applied to a hot dip galvanized steel sheet (JIS G3302 standard product, 150 × 70 × 0.8 mm) treated with zinc phosphate at a liquid temperature of 30. Electrodeposition coating was carried out at 15 ° C. so that the dry coating film was 15 μm. After washing with water, baking was performed at 160 ° C. for 30 minutes to obtain a cured electrodeposition coating film.

The appearance of the obtained cured electrodeposition coating film was visually evaluated based on the following criteria. The evaluation results are shown in the table.
○: The surface is smooth and the occurrence of repelling is not confirmed.
Δ: 1 to 10 repels are confirmed.
X: 11 or more repellents are confirmed.

^＊１：液体硬化触媒である
^＊２：顔料分散ペーストにおける平均粒径および分散安定性を示す。

^{* 1} : Liquid curing catalyst
^{* 2} : Shows the average particle size and dispersion stability of the pigment dispersion paste.

  As shown in Tables 1 and 2, the cured electrodeposition coating films obtained from the cationic electrodeposition coating compositions of the examples were excellent in coating film appearance. On the other hand, the cured electrodeposition coating film obtained from the cationic electrodeposition coating composition containing the liquid curing catalyst of Comparative Example 1 was inferior in coating film appearance. This is probably because the liquid curing catalyst agglomerated during baking and curing of the electrodeposition coating film, thereby causing repelling. Further, in the example of Comparative Example 2 in which the solid curing catalyst was dispersed using the pigment dispersion resin, it was confirmed that the dispersion stability of the solid curing catalyst was inferior. Further, in the example prepared by dispersing the solid curing catalyst and the pigment together in Comparative Example 3, the dispersion time required 3 times or more that of the other experimental examples. Also in this case, it was confirmed that the dispersion stability was inferior. Further, there is a problem that the viscosity of the obtained dispersion of the pigment and the solid curing catalyst is high.

Example 5 Preparation of Cationic Electrodeposition Coating Composition for Replenishment 93.2 parts of binder resin emulsion obtained in Production Example 5 and 4.7 parts of pigment dispersion paste obtained in Production Example 4 and water dispersion of Production Example 6 2.1 parts of the mold curing catalyst (c-1) was mixed to obtain a one-component replenishment cationic electrodeposition coating composition having a coating solid content concentration of 37% by weight.

Comparative Example 4 Preparation of Replenishment Cationic Electrodeposition Coating Composition 93.2 parts of the binder resin emulsion obtained in Production Example 5 and 6.8 parts of the pigment dispersion paste obtained in Comparative Example 3 were mixed to obtain a solid content of the paint. A 1-component cationic electrodeposition coating composition having a concentration of 37% by weight was obtained.

  The dispersion stability test was conducted in the same manner as described above for the replenishment cationic electrodeposition coating composition thus obtained. The results are shown in Table 3.

  As shown in Table 3, the one-component replenishment cationic electrodeposition coating composition using the water-dispersed curing catalyst according to the present invention in which a resin component, a pigment component, and a catalyst component are mixed may be a one-component type. Sedimentation did not occur and it was confirmed that the dispersion stability was very excellent. On the other hand, in the comparative one-component cationic electrodeposition coating composition for replenishment, the occurrence of precipitation was confirmed at an early stage. The replenishment of the electrodeposition coating composition currently performed is mainly a method of replenishing the resin component and the pigment catalyst component separately. In contrast, by using the water-dispersed curing catalyst in the present invention, it is possible to replenish the electrodeposition coating composition with one liquid.

  The cationic electrodeposition coating composition of the present invention is very excellent in dispersion stability. In the cationic electrodeposition coating composition of the present invention, by using the water-dispersed curing catalyst (c), it is possible to disperse the pigment and the solid curing catalyst under optimum conditions according to their dispersibility. Become. For this reason, problems such as precipitation of the solid curing catalyst and thickening of the pigment paste can be solved. Furthermore, since it can be dispersed under optimum conditions according to the solid curing catalyst and the pigment paste, there is an advantage that the preparation time of the pigment dispersion paste and the water dispersion type curing catalyst (c) is shortened as a result.

Claims (6)

An amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and
A water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, comprising a solid curing catalyst and a nonionic surfactant;
A cationic electrodeposition coating composition comprising:   The cationic electrodeposition coating composition according to claim 1, wherein the solid curing catalyst contained in the water-dispersed curing catalyst (c) is a tin compound or a bismuth compound.   The cation according to claim 1 or 2, wherein the water-dispersed curing catalyst (c) further comprises a compound selected from the group consisting of fatty acids, fatty acid derivatives, amine compounds and mixtures of one or more of them. Electrodeposition paint composition. An amine-modified epoxy resin (a); a blocked isocyanate curing agent (b); and
A water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, comprising a solid curing catalyst and a nonionic surfactant;
A one-component replenishment cationic electrodeposition coating composition having a coating solid content concentration of 30 to 50% by weight. A two-component cationic electrodeposition coating composition,
A binder resin emulsion in which the first liquid of the two-component replenishment cationic electrodeposition coating composition contains a water-dispersed curing catalyst (c) having an average particle size of 50 to 200 nm, which contains a solid curing catalyst and a nonionic surfactant. And the second liquid of the two-liquid replenishment cationic electrodeposition coating composition is a pigment-dispersed paste liquid,
Cationic electrodeposition coating composition for two-component replenishment.   A method for replenishing an electrodeposition coating composition comprising the step of putting the cationic electrodeposition coating composition for replenishment of one liquid according to claim 4 or the cationic electrodeposition coating composition for replenishment of two liquids according to claim 5 into an electrodeposition tank. .