JP2014091742A - Cationic electrodeposition coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cationic electrodeposition coating composition which hardly causes cissing of a coated film, sufficiently secures gloss and smoothness without impairing characteristics required for the cationic electrodeposition coating composition such as corrosion resistance, chemical resistance, adhesiveness to a base material and finish coating suitability and further secures initial characteristics even when a coating material stays for a long time.SOLUTION: There is provided a cationic electrodeposition coating composition which specifically comprises: as essential components, (1) a cationic resin (base resin) obtained by cationizing the amino group of a vinyl copolymer resin having an amino group and a hydroxyl group with an acid; (2) a blocked polyisocyanate (curing agent); and (3) a polyether polyol represented by the following general formula: general formula, [B]-[A]-[C], wherein, [A] represents a linking group having (CH(CH)CHO) as a repetition unit and [b] and [C] represents (CHCHO) as a repetition unit and a functional group in which one terminal is an OH group.

Description

In the present invention, by using a novel anti-repellent agent, problems due to repelling are unlikely to occur in the painting process and the subsequent baking process. Therefore, the present invention has excellent properties in coating smoothness and paint storage stability. The present invention relates to a vinyl resin-based cationic electrodeposition coating composition.

Electrodeposition coating is superior to air spray coating and electrostatic spray coating for parts having a bag structure, such as automobiles and electrical appliances. It has come to be widely put to practical use such as coat coating. However, the demand for electrodeposition coating has been advanced, and there is a demand for an electrodeposition coating with fewer defects in appearance of the coating film than in the prior art.

One of the defects in the paint film is a phenomenon called repellency. It is a pinhole due to volatilization of volatile components remaining in the paint film before baking, oil droplets originally present in the electrodeposition paint, or from the surroundings before baking. The cause is a crater by oil droplets scattered on the electrodeposition coating. In electrodeposition paints, the film-forming component is usually present in a particle state of around 100 nm in water. However, when the electrodeposition paint stays for a long time, some of the constituent components are detached from the particles. As a result, repelling is formed in the coating film, which causes a coating film defect.

In the prior art, for example, a method in which an extender pigment such as kaolin is added and increased to increase the pigment concentration in the paint to prevent repellency has been frequently used. However, although this method is effective in reducing repellency, there is a basic problem that the gloss of the coating film is inevitably lowered and sufficient coating film smoothness cannot be obtained.

There are also attempts to prevent repelling by using various additives in combination. That is, in patent document 1, it is a technique which uses silicone oil together as a repellency inhibitor. Silicone oil is a compound with a low SP value in the first place and is based on the idea that it is distributed at a high concentration in the upper layer of the coating film to suppress repellency. However, the slipperiness of the coating film becomes excessive, and electrodeposition coating When a top coat is further coated on the film, there is a problem in that the top coat adhesion is extremely lowered.

In Patent Document 2, a compound in which an alkylene glycol chain is further introduced into a partially blocked polyisocyanate is proposed as a repellency inhibitor, but the effect of reducing repellency is insufficient. Production examples in which a 12-hydroxystearic acid skeleton is further introduced into the above compound are also exemplified, but the structure is complicated and the molecular weight is increased, and the effect of reducing repellency is also insufficient.

In Patent Document 3, an acrylic resin having a specific structure is proposed as a repellency inhibitor. In the text [0016] of Patent Document 3, the application range of the base resin to be combined includes amine-modified epoxy resins or amine-modified acrylic resins. In the examples, amine-modified epoxy resins are exemplified. In fact, when the base resin as in the present invention is applied to an electrodeposition paint that is an amino group-containing vinyl resin, the effect of reducing repellency is insufficient. In Patent Document 4, a combination of a vinyl resin having a specific SP value and a polyalkylene glycol is proposed as a repellency inhibitor. In this case as well, as in Patent Document 3, it is represented by the component (A). It is a limited technology to be used in combination with amine-modified epoxy resins.

Japanese Patent Laid-Open No. 5-140489 JP-A-8-41390 JP 2000-7959 A JP 2001-89685 A

  Various required performances required for electrodeposition paints, such as corrosion resistance, chemical resistance, substrate adhesion, top coat suitability, etc. It is an object of the present invention to provide an electrodeposition paint excellent in storage stability, which is sufficiently ensured and even if the paint stays for a long time, the initial characteristics are ensured without any problem.

That is, the present invention has been made to solve the above problems. Specifically, in (a) vinyl copolymer resin containing (1) amino group and hydroxyl group as constituent components, the base number is 10 to 85 mgKOH. / G-solid, a hydroxyl value of 20 to 200 mg KOH / g-solid, a cationic resin (base resin) in which the amino group is cationized with an acid, (2) a blocked polyisocyanate (curing agent), and (3) It is a cationic electrodeposition coating composition containing a polyether polyol represented by the following general formula as an essential component,
General Formula [B]-[A]-[C] Here, [A] represents a linking group having (CH (CH ₃ ) CH ₂ O) as a repeating unit.
[B], [C]: represents a functional group having (CH ₂ CH ₂ O) as a repeating unit and one terminal being an OH group.

(B) Further, the molecular weight of [A] of the polyether polyol (3) is 1600 to 3000, and the total of [B] and [C] is 15 to 65% by weight in the whole (3). A cationic electrodeposition coating composition,

(C) Further, the cationic electrodeposition coating composition in which the polyether polyol (3) is 0.5 to 10 parts by weight with respect to 100 parts by weight of the total solid content of the cationic resin (1) and the block polyisocyanate (2). A composition,

(D) Furthermore, the cationic electrodeposition coating composition in which the polyether polyol (3) is 1 to 5 parts by weight with respect to 100 parts by weight of the total solid content of the cationic resin (1) and the block polyisocyanate (2). And

(E) Furthermore, it is a cationic electrodeposition coating composition in which the molecular weight of [A] of the polyether polyol (3) is 1900 to 2500, and the sum of the parts [B] and [C] is the total of (3) In particular, the cationic electrodeposition coating composition is 25 to 55% by weight.

  By applying the electrodeposition paint of the present invention, almost no repellency occurs in the appearance of the coating without impairing various required performances such as anticorrosion, chemical resistance, adhesion to the base material, suitability for top coating, etc. , Gloss and smoothness are sufficiently secured. Even when the paint stays for a long time, the initial characteristics can be secured without any problem.

Below, the cationic electrodeposition coating composition of this invention is demonstrated in detail.
[Cationic Resin (1)]
The vinyl copolymer resin which is a precursor of the cationic resin (1) of the present invention contains an amino group. This amino group imparts water dispersibility and electrophoretic properties, and examples of means for introducing an amino group include copolymerization of an amino group-containing unsaturated monomer and an amino group-free unsaturated monomer. Or a method in which a glycidyl group-containing unsaturated monomer and a glycidyl group-free unsaturated monomer are copolymerized and an amino group-containing compound is reacted with the glycidyl group. There is also a method in which an amino group-containing compound is first reacted with a glycidyl group-containing unsaturated monomer, and then a glycidyl group-free unsaturated monomer is copolymerized.

Examples of amino group-containing unsaturated monomers include dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropylacrylamide, diallylamine, and the like. Can be used. Examples of the glycidyl group-containing unsaturated monomer include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and the like, and one kind or a mixture of two or more kinds can be used. Examples of amino group-containing compounds to be reacted with glycidyl groups include methylamine, ethylamine, n-propylamine, isopropylamine, monoethanolamine, diethylamine, diethanolamine, N-methylethanolamine, N-ethylethanolamine, ethylenediamine, Examples include diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, dimethylaminopropylamine, and mixtures thereof. The primary amino group is reacted with a ketone in advance to form a block, and then the remaining activity. Hydrogen and an epoxy group may be reacted.

The base number in the vinyl copolymer resin used in the present invention is designed in the range of 10 to 85 mgKOH / g-solid, more preferably 20 to 75 mgKOH / g-solid. If the base number is less than 10 mgKOH / g-solid, sufficient water dispersibility and electrophoretic properties cannot be ensured, and if it exceeds 85 mgKOH / g-solid, the coating film becomes brittle and the water resistance is lowered to obtain sufficient performance. It's hard to be done.

The vinyl copolymer resin used in the present invention has a hydroxyl group. The hydroxyl group reacts with the blocked polyisocyanate (2) during baking of the coating film to impart curability. As a means for introducing the hydroxyl group, a hydroxyl group-containing unsaturated monomer is copolymerized. Examples include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate. And these lactone-modified products can be used, and one or a mixture of two or more can be used.

  The hydroxyl value in the vinyl copolymer resin is designed in the range of 20 to 200 mgKOH / g-solid, more preferably 40 to 160 mgKOH / g-solid. When the hydroxyl value is less than 20 mgKOH / g-solid, sufficient curability is not ensured, and when it exceeds 200 mgKOH / g-solid, the coating film becomes brittle, water resistance is lowered, and sufficient performance is hardly obtained.

  Furthermore, in the vinyl copolymer resin used in the present invention, an amino group-containing unsaturated monomer, a glycidyl group-containing unsaturated monomer obtained by reacting an amino group-containing compound, or a hydroxyl group-containing unsaturated monomer As the monomer, other unsaturated monomers can be copolymerized, and for other unsaturated monomers, acrylic acid or methacrylic acid alkyl esters, or other vinyl monomers and amide monomers. A mer can be used. Specific examples of the compound include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl. Acrylic acid such as methacrylate, t-butyl acrylate, t-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, heptyl acrylate, heptyl methacrylate or the like Methacrylic acid Alkyl monomers, styrene, α-methylstyrene, vinyl toluene, vinyl acetate, acrylonitrile, methacrylonitrile, and other vinyl monomers, acrylamide, methacrylamide, methylol acrylamide, methylol methacrylamide, methoxymethyl acrylamide, n-butoxymethyl acrylamide, Examples thereof include amide monomers such as diacetone acrylamide and diacetone methacrylamide, ethylene glycol diacrylate, ethylene glycol dimetallate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate. These may be used alone or in combination of two or more.

  The content of the other unsaturated monomer in the vinyl copolymer resin is preferably 40 to 90% by weight, and more preferably 60 to 80% by weight.

  In the vinyl copolymer resin used in the present invention, Tg (glass transition temperature) is preferably 0 to 50 ° C., and specific values of Tg are usually calculated from the Fox equation. Moreover, the range of a weight average molecular weight is 3,000-100,000, Preferably it is 6,000-70,000, More preferably, it is 10,000-50,000, and is normally calculated | required by GPC analysis. .

  The above-mentioned vinyl copolymer resin is obtained by polymerizing each unsaturated monomer by a known method such as solution polymerization, non-aqueous dispersion polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, etc. Preferably, the reaction temperature is usually 40 to 170 ° C.

  Reaction solvents include n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, propyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono It is preferable to use a hydrophilic solvent such as butyl ether. Moreover, as a polymerization initiator, well-known things, such as an organic peroxide, an azo compound, ammonium persulfate, potassium persulfate, can be used.

A specific method for cationizing the vinyl copolymer resin used in the present invention can be carried out by neutralizing an amino group with a protonic acid. Particularly preferred acids include formic acid, acetic acid, lactic acid, and propionic acid. , Citric acid, malic acid, sulfamic acid phosphoric acid, toluene sulfonic acid, naphthalene sulfonic acid and the like, or a mixture thereof. The neutralization degree of the acid is preferably 15 to 85%.

[About blocked polyisocyanate (2)]
The blocked polyisocyanate (2) in the present invention is a reaction product of a polyisocyanate and a blocking agent, and the polyisocyanate is an aromatic or aliphatic (including alicyclic) polyisocyanate. 2,4- or 2,6-tolylene diisocyanate and mixtures thereof, p-phenylene diisocyanate, diphenylmethane-4,4'-diisocyanate, polymethylene polyphenyl isocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, cyclohexylmethane -4,4'-diisocyanate, 1,3 or 1,4-bis- (isocyanatomethyl) -cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, bis- (isocyanate) Tomethyl) -norbornane, 3 or 4-isocyanatomethyl-1-methylcyclohexyl isocyanate, m- or p-xylylene diisocyanate, m- or p-tetramethylxylylene diisocyanate, and a burette modified or isocyanurate modified of the above isocyanate. Or a part of the isocyanate group of the above isocyanate, ethylene glycol, propylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexanediol and other low molecular diols, polyethylene glycol , Polypropylene glycol, polytetramethylene glycol, oligomeric diols such as polylactone diol, trimethylolethane, It can be exemplified trimethylolpropane, polyisocyanate or a mixture thereof linked with a polyol such as pentaerythritol.

Examples of blocking agents include aliphatic alcohol compounds such as methanol, ethanol, n-butanol and 2-ethylhexanol, cellosolve compounds such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether and the like. Carbitol compounds, oxime compounds such as acetone oxime, methyl ethyl ketone oxime, cyclohexanone oxime, lactam compounds such as ε-caprolactam, phenol compounds such as phenol, cresol, xylenol, acetoacetic acid ethyl ester, malonic acid diethyl ester, etc. Mention may be made of methylene group-containing compounds.

The reaction between the polyisocyanate and the blocking agent can be carried out in a solvent or in a melt without a solvent. Solvents used in the reaction include solvents that do not react with polyisocyanates, such as ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and isophorone, and aromatic hydrocarbons such as toluene, xylene, chlorobenzene, and nitrobenzene. And cyclic ethers such as tetrahydrofuran and dioxane, and halogenated hydrocarbons such as chloroform and carbon tetrachloride. Although there is no limitation in particular about reaction temperature, Preferably it is 30-150 degreeC.

The content ratio of the vinyl copolymer resin and the blocked polyisocyanate (2) used in the present invention is 90 to 40/10 to 60, preferably 85 to 40/15 to 60, and more preferably in terms of solid content. 80-55 / 20-45.

[Polyether polyol (3)]
The polyether polyol (3) in the present invention is a compound having (CH (CH ₃ ) CH ₂ O) and (CH ₂ CH ₂ O) as repeating units in one molecule. It can be expressed by a formula. Generally, it is called a pluronic-type polyether polyol.
General Formula [B]-[A]-[C] Here, [A] represents a linking group having (CH (CH ₃ ) CH ₂ O) as a repeating unit.
[B], [C]: represents a functional group having (CH ₂ CH ₂ O) as a repeating unit and one terminal being an OH group.

About the molecular weight of [A] of polyether polyol (3), Preferably it is 1600-3000, More preferably, it is 1900-2500. The total of the [B] and [C] parts of the polyether polyol (3) is preferably 15 to 65% by weight, more preferably 25 to 55% by weight in the whole (3). . Further specific examples of commercially available products are preferably Sanyo Chemical Industries, New Pole PE-62, PE-64, ADEKA, Adeka Pluronic L-62, L-64, L- 72, manufactured by BASF, Pluronic L62, L63, L64, P65, L92, etc., more preferably Sanyo Chemical Industries, New Pole PE-74, PE-75, ADEKA, Adeka Pluronic P-84, P-85, manufactured by BASF, Pluronic P84, P85, and the like can be mentioned, but are not limited thereto.

The content ratio of the polyether polyol (3) in the present invention is preferably 0.5 to 10 parts by weight, more preferably based on the total 100 solids weight of the vinyl copolymer resin and the blocked polyisocyanate (2). Is 1 to 5 parts by weight.

  Moreover, a normal coating additive can be added to the cationic electrodeposition coating composition of the present invention as required. Illustrative examples include pigments such as titanium white, carbon black, and bengara, extender pigments such as talc, calcium carbonate, mica, clay, and silica, aluminum molybdate, zinc molybdate, calcium molybdate, zinc phosphomolybdate, and phosphomolybdic acid. Aluminum, zinc phosphate, iron phosphate, aluminum phosphate, calcium phosphate, zinc phosphite, aluminum phosphite, zinc cyanide, zinc oxide, aluminum tripolyphosphate, calcium ferrite, magnesium ferrite, zinc ferrite, bismuth oxide, water Examples thereof include rust preventive pigments such as bismuth oxide, antifoaming agents, aqueous solvents, and curing catalysts. Moreover, other resin, for example, an acrylic resin, a polyester resin, a urethane resin, and a butadiene resin can be contained.

  The cationic electrodeposition coating composition of the present invention can be applied to the surface of a desired material by known cationic electrodeposition coating. Specifically, the solid content concentration of the paint is preferably 5 to 40% by weight, more preferably 15 to 25% by weight, the pH is adjusted to 5 to 8 according to the amount of acid used, the liquid temperature is 15 to 45 ° C., the load Although the object to be coated can be applied as a cathode under the condition of a voltage of 100 to 450 V, it is not limited to this condition. The coated object to be coated is washed with water and then baked at a temperature of 100 to 220 ° C. for 10 to 30 minutes in a baking oven to obtain a cured coating film. Although there is no restriction | limiting in the coating film thickness obtained, 5-60 micrometers in a cured coating film, Preferably 10-40 micrometers is suitable.

EXAMPLES Next, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. In addition, unless otherwise indicated, the compounding quantity in a table | surface represents a weight part and weight%.

[Production of vinyl copolymer resin used for cationic resin (1)]
Production Example 1 (Production of Resin Liquid (1-1))
A reactor having a stirring device, a thermometer, a monomer dropping device, and a reflux cooling device is prepared. A reactor is charged with 15.7 parts of propylene glycol monomethyl ether and 3.9 parts of isopropanol, and the temperature is raised to the reflux temperature with stirring. 23.5 parts of n-butyl acrylate, 15.7 parts of methyl methacrylate, 15.7 parts of styrene Then, 11.8 parts of 2-hydroxylethyl acrylate, 11.8 parts of dimethylaminoethyl methacrylate, and 1.6 parts of azobisisobutylnitrile were mixed in advance and then dropped over 2 hours. The temperature was maintained at the reflux temperature. After 1.5 hours from the end of dropping, 0.3 part of azobisisobutylnitrile was added, and the reaction was further continued at the same temperature for 1.5 hours to obtain a transparent and viscous resin liquid (1-1). Its solid content is 80.0 (%), Tg is 10.1 (° C.), hydroxyl value is 72.5 (mgKOH / g-solid), base value is 53.6 (mgKOH / g-solid), weight average The molecular weight was 16,000.

[Production of blocked polyisocyanate (2)]
Production Example 2 (Production of Resin Liquid (2-1))
In a reaction vessel equipped with a stirrer, a thermometer, and a cooling tube, 133.0 parts of isophorone, 150.0 parts of toluene, 333.0 parts of VESTANAT T-1890 / 100 (nuphorate of isophorone diisocyanate manufactured by Degussa AG), coronate HX (Nulate body of hexamethylene diisocyanate manufactured by Nippon Polyurethane Co., Ltd.) 300.0 parts was charged and heated to 60 ° C. Next, 261.0 parts of methyl ethyl ketone oxime was added dropwise over 1 hour while maintaining 60 ° C., and the mixture was further kept at 60 ° C. for 2 hours. Finally, 100.0 parts of propylene glycol monomethyl ether was charged to obtain a blocked polyisocyanate (2-1) having a solid content of 75%.

[Preparation of water-dispersed resin liquid]
Production Examples 3 to 9 (Production of water-dispersed resin liquids 1 to 7)
According to the formulation shown in Table 1, deionized water (9) was gradually added to the mixed resin neutralized product of (1) to (8) with good stirring to obtain respective water-dispersed resin liquids. Table 1 also shows the weight percent of the polyether polyol (3) based on 100 parts by weight of the total of the cationic resin (1) and the blocked polyisocyanate (2).

[Description of raw materials]
New Pole PE-74
Polyether polyol (3) manufactured by Sanyo Chemical Co., Ltd.
Molecular weight of [A]: 2050
Total of [B] and [C] parts in (3): 40% by weight
Adeka Pluronic P-85
Polyether polyol (3) manufactured by ADEKA Corporation
Molecular weight of [A]: 2250
Total of [B] and [C] parts in (3): 50% by weight
Adeka Pluronic L-121
Polyether polyol (3) manufactured by ADEKA Corporation
Molecular weight of [A]: 3850
Total of [B] and [C] parts in (3): 10% by weight
Adeka Pluronic F-38
Polyether polyol (3) manufactured by ADEKA Corporation
Molecular weight of [A]: 950
Total of [B] and [C] parts in (3): 80% by weight

[Adjustment of pigment paste]
Production Examples 10 and 11 (Production of Pigment Pastes 1 and 2)
According to the formulation shown in Table 2, (1) to (6) were sufficiently stirred with a dissolver, and then dispersed using a horizontal sand mill until the particle gauge particle size became 10 μm or less to obtain respective pigment pastes.

[Description of raw materials]
MA-100 Carbon Black Taipure R-900 manufactured by Mitsubishi Chemical Corporation Titanium oxide manufactured by DuPont KC-100 manufactured by Kyodo Pharmaceutical Co., Ltd. Dibutyltin oxide

[Preparation of electrodeposition paint]
The water-dispersed resin liquid, ion-exchanged water, and pigment paste were blended as shown in Table 3 to obtain electrodeposition paints of Examples and Comparative Examples, respectively.

[Preparation of coating test plate and test results]
Using the electrodeposition paint obtained above, a carbon electrode as an anode and a zinc phosphate-treated plate (PB-L3080, 0.8 × 70 × 150 mm manufactured by Nippon Test Panel Co., Ltd.) as a cathode, and a film after baking Electrodeposition coating was performed under the condition that the thickness was 20 μm, and baking was performed at 150 ° C. for 25 minutes. Table 4 shows the properties of the electrodeposition paint and the coating performance test results.

The evaluation methods of paint and coating film performance are as follows.
(1) Repelling resistance (initial paint evaluation)
Observe the appearance of the paint film and observe the presence or absence of repellency and craters.
○: No repellent or crater is generated ×: Repelled or crater is generated (2) Gloss of coating film Measure the specular reflectance at 60 degrees with a gloss meter.
(3) Ra
Ra is measured with a surface roughness meter.
Measurement conditions Cut-off: 2.5mm
Feeding speed: 0.5 mm / second (4) Salt spray resistance test Performed according to JIS-Z-2371. A scratch reaching the substrate is put on the electrodeposited surface with a cutter knife, and the rust width after 500 hours is evaluated.
○: Corrosion width of 3.0 mm or less from scratches on cutter knife ×: Corrosion width exceeds 3.0 mm from scratches on cutter knife (5) Acid resistance 20 ° C. After 120 hours immersion in 5% sulfuric acid aqueous solution Observe the surface condition.
○: Almost no difference in gloss and appearance ×: Difference in gloss and appearance (6) Alkali resistance After immersing in 1% sodium hydroxide aqueous solution at 20 ° C. for 120 hours, the coated surface state was observed.
○: Almost no difference in gloss and appearance ×: Difference in gloss and appearance (7) Cross-cut adhesion Adhering cellophane tape on top of 100 cross-cuts with a knife width of 1 mm on the coated plate After that, the state of adhesion when the cellophane tape is quickly peeled off is observed.
○: No peeling ×: Peeling (8) Applicability for top coating After applying the top coating to the electrodeposition coated plate, a cross-cut adhesion test with a width of 2 mm is performed.
Top coating conditions Paint: Super Glymine # 1000 Baking conditions manufactured by Shinto Paint Co., Ltd .: 140 ° C. × 20 minutes Film thickness: 30 μm
○: No peeling with respect to the top coat ×: There is peeling with respect to the top coat (9) Storage stability The coating was kept stirred at 30 ° C. for one month while keeping the sealed state so that moisture etc. would not fly, and then electrodeposition was performed. Observe the occurrence of abnormalities on the appearance of the coating film.
○: As with the initial electrodeposition result, no repellency or crater is generated. ×: As with the initial electrodeposition result, repellency or crater is generated. XX: Compared with the initial electrodeposition result, repellency or crater increases. ing

According to the present invention, there is almost no repellency in the appearance of the coating film, gloss and smoothness are sufficiently achieved, and there are no problems with the characteristics of conventional paints in terms of anticorrosion, chemical resistance, adhesion to the substrate, suitability for top coating, etc. A cationic electrodeposition coating composition that is ensured can be obtained.

Claims (5)

(1) A vinyl copolymer resin containing an amino group and a hydroxyl group as a constituent component, the base value is 10 to 85 mgKOH / g-solid, the hydroxyl value is 20 to 200 mgKOH / g-solid, and the amino group is an acid and a cation A cationic electrodeposition coating composition comprising, as essential components, a converted cationic resin (base resin), (2) a blocked polyisocyanate (curing agent), and (3) a polyether polyol represented by the following general formula: object.
General Formula [B]-[A]-[C] Here, [A] represents a linking group having (CH (CH ₃ ) CH ₂ O) as a repeating unit.
[B], [C]: represents a functional group having (CH ₂ CH ₂ O) as a repeating unit and one terminal being an OH group.   The molecular weight of [A] of the polyether polyol (3) is 1600 to 3000, and the total of [B] and [C] is 15 to 65% by weight in the total of (3). The cationic electrodeposition coating composition described in 1.   The polyether polyol (3) is 0.5 to 10 parts by weight based on 100 parts by weight of the total solid content of the cationic resin (1) and the blocked polyisocyanate (2). The cationic electrodeposition coating composition as described.   The polyether polyol (3) is 1 to 5 parts by weight based on 100 parts by weight of the total solid content of the cationic resin (1) and the blocked polyisocyanate (2). 4. The cationic electrodeposition coating composition according to 3. The molecular weight of [A] of the polyether polyol (3) is 1900 to 2500, and the sum of the [B] and [C] parts is 25 to 55% by weight in the whole (3). The cationic electrodeposition coating composition according to claim 2, 3 or 4.