KR102042239B1 - Cationic urethane curing agent and electro-deposition paint composition comprising the same - Google Patents

Abstract

The present invention relates to a cationic urethane curing agent and an electrodeposition coating composition comprising the same.

Description

Cationic urethane curing agent and electrodeposition coating composition comprising the same {CATIONIC URETHANE CURING AGENT AND ELECTRO-DEPOSITION PAINT COMPOSITION COMPRISING THE SAME}

The present invention relates to a urethane curing agent having a cationicity and an electrodeposition coating composition comprising the same.

Most of the energy used for electrodeposition coatings in automotive production plants is spent in ovens that cure the painted electrodeposition paints. At this time, the oven installation space and the curing efficiency is limited, whereas the vehicle body of the car is gradually increasing, the problem that the hardened weak portion occurs. That is, due to the thickening of the car body, the time required for the electrodeposition paint coated on the car body to reach the temperature required for curing, that is, PMT (Peak Metal Temperature) is long, and the curing efficiency in the existing curing system is reduced.

Accordingly, in order to save energy consumed for hardening and to secure hardenability of a large vehicle body in a limited oven space, development of electrodeposition paints capable of curing at lower temperatures is required in the automotive industry.

In response to this demand, there has been a corresponding movement in the direction of increasing the content of the curing accelerator or the curing agent contained in the electrodeposition paint. However, when the content of the curing accelerator is increased, the appearance (gloss and roughness) of the coating film is decreased, and when the content of the curing agent is increased, the internal coating resistance, corrosion resistance, etc. are deteriorated due to the decrease in the content of the subject matter.

In addition, attempts have been made to ensure the hardenability of the electrodeposition paint using a curing agent combined with a low dissociation temperature of alcohol, phenol, oxime, lactam and the like. In particular, many cases have been reported that the curing agent bonded to the oxime as a blocking agent improves the curing property. However, the oxime has a very low dissociation temperature and, when combined with an aromatic isocyanate used as a curing agent, greatly reduces the stability of the electrodeposition resin, and thus can be used only for aliphatic isocyanates.

Accordingly, there is a demand for development of a technology capable of securing curability even at a relatively low temperature without deteriorating the physical properties of the coating film.

Republic of Korea Patent Publication No. 1998-080601

The present invention provides a cationic urethane curing agent that can secure the curability of the electrodeposition coating composition even at a relatively low temperature.

Moreover, this invention provides the electrodeposition coating composition which can form the coating film excellent in physical property.

The present invention provides a cationic urethane curing agent obtained by neutralizing a reactant of a tertiary amine compound having a hydroxy group with an isocyanate compound with an acid neutralizer.

Moreover, this invention provides the electrodeposition coating composition containing an electrodeposition resin part, a pigment part, the hardening additive part containing the said cationic urethane hardening | curing agent, and a solvent part.

The cationic urethane curing agent of the present invention can smoothly provide a reactor (isocyanate group) that can participate in the curing of the electrodeposition coating composition, so that the coating film can be stably cured even at a relatively low temperature (for example, 150 ° C. or less). have. In addition, the cationic urethane curing agent of the present invention can increase the electrical conductivity of the electrodeposition coating composition when applied to the electrodeposition coating composition due to the monomolecular and cationic properties to increase the internal coating properties of the electrodeposition coating composition.

Hereinafter, the present invention will be described in detail.

One. Cationic  Urethane curing agent

The cationic urethane curing agent of the present invention is obtained by first neutralizing a reactant obtained by first reacting a tertiary amine compound having a hydroxy group with an isocyanate compound with an acid neutralizer, and the components used in each reaction will be described in detail. As follows.

The tertiary amine compound used to obtain the reactant is a hydroxy group (OH) is bonded, imparts water-soluble, cationic properties to the cationic urethane curing agent and serves to block the curing reactivity of the cationic urethane curing agent. Specifically, the hydroxyl group bonded to the tertiary amine compound forms a urethane bond with an isocyanate group (NCO) bonded to the isocyanate compound to block the reactivity of the isocyanate group to block the curing reactivity of the cationic urethane curing agent.

Such tertiary amine compounds include 2-dimethylaminoethanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-diethylaminoethanol, 4-dimethylamino-1-butanol, 2-dimethyl One or more selected from the group consisting of amino-2-methylpropanol, and 4-dimethylamino-1-butanol may be used.

As the tertiary amine compound, a compound obtained by reacting a primary amine compound or a secondary amine compound with a monoepoxide may be used. Since the primary amine compound or the secondary amine compound may have an active hydrogen present and cause unwanted side reactions with the isocyanate compound described below, a compound obtained by reacting with a monoepoxide may be used rather than using them directly. have.

The reaction ratio in the reaction of the primary amine compound and the monoepoxide may be an equivalent ratio of 1: 2.0 to 2.5, specifically, the equivalent ratio of 1: 2.01 to 2.1. In addition, the reaction ratio in the reaction of the secondary amine compound and the monoepoxide may be an equivalent ratio of 1: 1.0 to 1.5, specifically, may be an equivalent ratio of 1: 1.01 to 1.1.

The primary amine compounds include ethanolamine, 3-amino-1-propanol, amino-2-propanol, 2-amino-2-methyl-1-propanol, 2-amino-3-methyl-1-butanol, and 5 One or more selected from the group consisting of -amino-1-pentanol can be used.

As the secondary amine compound, at least one selected from the group consisting of 2-methylaminoethanol, 2-ethylaminoethanol, 3-methylamino-1-propanol, and 2-isopropylaminoethanol may be used.

As the monoepoxide, glycidyl ester of monohydric acid or glycidyl ether may be used. Specifically, monoepoxide includes glycidyl acrylate, glycidyl methacrylate, glycidyl acetate, glycidyl butyrate, glycidyl palmitate, glycidyl laurate, butyl glycidyl ether, 2 At least one selected from the group consisting of -ethylhexyl glycidyl ether, phenyl glycidyl ether, and P- (tert-butyl) phenyl glycidyl ether may be used, or a compound represented by the following Chemical Formula 1 may be used.

[Formula 1]

In Formula 1, R ¹ and R ² are the same as or different from each other, and each independently an alkyl group having 1 to 10 carbon atoms.

The isocyanate compound used to obtain the reactant serves to provide an isocyanate group participating in the curing reaction.

Such isocyanate compounds include 4,4'-methylenebis (phenylisocyanate) (MDI), 4-methyl-1,3-phenylene diisocyanate, polymeric methylenediphenyl diisocyanate (polymeric MDI), hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), 2,4,6-triisopropylphenyl diisocyanate (TIDI), diphenyl ether diisocyanate, isophorone diisocyanate (IPDI), 4,4'-dicyclohexyl In the group consisting of methane diisocyanate (MDI), tetramethylxylene diisocyanate (TMXDI), 2,2,4-trimethylhexamethylene diisocyanate (TMHDI), and 2,4,4-trimethylhexamethylene diisocyanate (TMDI) One or more selected may be used.

The reaction ratio (isocyanate group: hydroxy group) in the reaction of the isocyanate compound and the tertiary amine compound may be an equivalent ratio of 1: 1.0 to 1.1, and specifically, may be an equivalent ratio of 1: 1.01 to 1.05.

The reactant obtained through the reaction of the tertiary amine compound and the isocyanate compound is neutralized with the acid neutralizing agent (specifically, neutralization of the amine group derived from the tertiary amine compound) to obtain the cationic urethane curing agent of the present invention. .

When the reactant that is not neutralized with the acid neutralizer is used as a curing agent component of the electrodeposition coating composition, it may be precipitated without proper mixing of the curing agent components in the electrodeposition coating composition. However, since the cationic urethane curing agent of the present invention is obtained by neutralizing the reactant with the acid neutralizing agent, the cationic urethane curing agent may be mixed well without being precipitated when used as a curing agent component of the electrodeposition coating composition.

As the acid neutralizer for neutralizing the reactants, one or more selected from the group consisting of acetic acid, lactic acid, formic acid, sulfonic acid, and methanesulfonic acid may be used.

The neutralization rate of the reactant and the acid neutralizer may be defined by Equation 1 below. In this case, the neutralization rate obtained by the following Equation 1 may be 5 to 150%, specifically 70 to 120%. When the neutralization rate is less than 5%, the water dispersibility may be lowered. When the neutralization rate is higher than 150%, the acid content may increase, thereby lowering the pH of the electrodeposition coating composition, thereby causing appearance defects such as re-dissolution of the coating film. .

[Equation 1]

(Acid equivalent of acid neutralizer / amine equivalent of reactant) × 100

The cationic urethane curing agent of the present invention obtained through such a neutralization reaction increases isocyanate groups that can participate in the curing reaction, and when used in the electrodeposition coating composition, it is possible to secure stable curing properties even at a lower temperature and to increase the crosslinking density of the coating film to increase corrosion resistance. It can contribute to forming a coating film excellent in physical properties. In addition, the tertiary amine compound is cationic due to the neutralization reaction, and thus has a water-soluble property. When the cationic urethane curing agent of the present invention is used in the electrodeposition coating composition, the electrical conductivity of the electrodeposition coating composition is increased, thereby improving the internal coating property. Can be.

When the cationic urethane curing agent of the present invention is used in the electrodeposition coating composition, the isocyanate group that has been blocked in reactivity is dissociated at a predetermined temperature or more to participate in the curing reaction together with the curing agent existing in the electrodeposition resin portion. Specifically, the electrodeposition coating composition comprising the cationic urethane curing agent of the present invention is as follows.

2. Electrodeposition Coating Composition

The electrodeposition coating composition of the present invention includes an electrodeposition resin portion, a pigment portion, a curing additive portion, and a solvent portion.

The electrodeposition resin part included in the electrodeposition coating composition of the present invention plays a role of imparting main physical properties (adhesiveness, corrosion resistance, etc.) to the coating film. The electrodeposition resin part may include an electrodeposition resin for forming a coating film, a curing agent for curing, a first solvent for controlling auxiliary physical properties, and other additives.

As the electrodeposition resin, a resin usually used in the preparation of the electrodeposition coating composition may be used. Specifically, an epoxy resin having an epoxy equivalent of 180 to 2,000 may be used as the electrodeposition resin. Examples of the epoxy resins include polyglycidyl ethers of polyphenols and polyglycidyl ethers of aromatic polyols such as bisphenol A.

As the curing agent, a urethane curing agent which is usually used may be used.

As the first solvent, deionized water, an aromatic solvent, an alcohol solvent, a ketone solvent, and the like, which are commonly used, may be used.

As the other additives, a conventional oil-improving agent, antifoaming agent, and the like may be used.

Such electrodeposition resin portion may be included in 40 to 50 parts by weight based on 100 parts by weight of the electrodeposition coating composition. When the content of the electrodeposition resin portion is less than 40 parts by weight, the physical properties of the coating film may be lowered, and when it exceeds 50 parts by weight, the paintability may be lowered due to the lower viscosity.

The pigment part contained in the electrodeposition paint composition of the present invention serves to increase the mechanical strength of the coating film or to impart color to the coating film. This pigment portion may include an organic-inorganic pigment, a dispersion resin, a catalyst, an acid component for stabilization, and a second solvent for viscosity control.

As the organic-inorganic pigments, organic-inorganic pigments commonly used (for example, titanium dioxide, carbon black, silicates, etc.) may be used.

As said dispersion resin, the resin for pigment dispersion normally used can be used.

As the catalyst, tin catalysts which are commonly used may be used.

As said acid component, the acid component normally used (for example, acetic acid etc.) can be used.

As the second solvent, deionized water, an aromatic solvent, an alcohol solvent, a ketone solvent, and the like, which are commonly used, may be used.

Such a pigment part may be included in an amount of 5 to 10 parts by weight based on 100 parts by weight of the electrodeposition paint composition. When the content of the pigment portion is less than 5 parts by weight, the mechanical strength of the coating film may be lowered or it may be difficult to impart the required color to the coating film, and when it exceeds 10 parts by weight, economic efficiency and paintability may be lowered.

The curing additive part included in the electrodeposition coating composition of the present invention serves to induce the curing reaction of the electrodeposition resin part. This curing additive portion includes a cationic urethane curing agent and a third solvent for dispersion / viscosity control.

Description of the cationic urethane curing agent is described in the '1. It is the same as described in the section 'Cationic Urethane Curing Agent' and will be omitted.

As the third solvent, deionized water, an aromatic solvent, an alcohol solvent, a ketone solvent, etc. which are commonly used may be used.

Such a curing additive part may be included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the electrodeposition paint composition. When the content of the curing additive part is less than 1 part by weight, uncuring of the coating film may be caused. When the content of the curing additive part exceeds 5 parts by weight, the physical properties of the coating film may be reduced due to overcuring.

The solvent portion included in the electrodeposition coating composition of the present invention serves to adjust the dispersibility and viscosity of the electrodeposition coating composition. Such a solvent part includes a fourth solvent which is commonly used, and deionized water, an aromatic solvent, an alcohol solvent, a ketone solvent, and the like may be used as the fourth solvent.

Such a solvent part may be included in an amount of 40 to 50 parts by weight based on 100 parts by weight of the electrodeposition coating composition. When the content of the solvent portion is less than 40 parts by weight, paintability may decrease due to low viscosity, and when the content of the solvent portion exceeds 50 parts by weight, physical properties of the coating film may be reduced or a long time may be consumed for curing.

As such, the electrodeposition coating composition of the present invention may have a content of 15 to 25% by weight of solids.

The electrodeposition coating composition of the present invention may be coated through a conventional electrodeposition coating method. Specifically, after the electrodeposition coating composition is contacted with the negative electrode substrate and the positive electrode substrate, respectively, electrodeposition coating may be performed by applying a DC voltage ranging from several V to several hundred V. After the electrodeposition coating, the cured coating film may be formed through a washing process and a curing process.

Hereinafter, the present invention will be described in detail with reference to the following Examples. However, the following examples are merely to illustrate the invention, the present invention is not limited by the following examples.

[ Example  1] Preparation of the curing additive part 1

62.7 g of ethanolamine were added to the reactor and heated to 60 ° C., and then 498.0 g of glycidyl ester (Shell, Cardura E-10P) was slowly added dropwise for 1-2 hours. After completion of the dropwise addition, the temperature of the reactor was raised to 80 ° C. under a nitrogen atmosphere, and the reaction was maintained for 4-8 hours.

When it was confirmed that there was no residual epoxy group, 36.8 g of methyl isobutyl ketone was added and 139.3 g of polymeric methylenediphenyl diisocyanate (Dow Chemical, PAPI2940) was added dropwise over 2 hours while maintaining the temperature at 80 to 90 ° C. After completion of the dropwise addition, the reaction was allowed to stand at 90 DEG C for 90 minutes or more under nitrogen atmosphere so that no NCO- remained.

If it is confirmed that there is no residual NCO-, the reaction is cooled to 60 ° C., and then 49.3 g of acetic acid (99.5%) is added and stirred for 30 minutes. Through the process of adding and g-solubilizing, the curing additive part 1 was prepared (neutralization rate: 80%).

[ Example  2] Preparation of the curing additive part 2

Except that 2-methylaminoethanol was used instead of ethanolamine, the hardening additive part 2 was manufactured through the same process as Example 1 (neutralization rate: 80%).

[ Example  3] Preparation of curing additive part 3

Except for using 2-dimethyl amino ethanol instead of the reaction of ethanolamine and glycidyl ester through the same process as in Example 1 to prepare a curing additive part 3 (neutralization rate: 80%).

ingredient Example 1 Example 2 Example 3 Ethanolamine 62.7 - - 2-methylaminoethanol - 116.0 - 2-dimethyl aminoethanol - - 229.8 Glycidyl ester 498.0 374.5 - Methyl isobutyl ketone 36.8 36.8 30.3 Polymeric Methylene Diphenyl Diisocyanate 139.3 209.4 346.1 Acetic acid (99.5%) 49.3 74.2 124.1 Butyl Cellosolve 86.7 86.7 71.3 Deionized water 127.2 102.4 198.4 Total (g) 1,000 1,000 1,000

[ Example  4] Pigment part  Produce

227.3 g of a pigment dispersion resin (KCC, cationic pigment dispersion resin) was charged into a reactor, 3.0 g of acetic acid (50%), 3.0 g of carbon black, 49.6 g of dibutyltin oxide, and titanium dioxide (Kermerus, R900) 226.5 g and 95.9 g of aluminum silicate (BASF, Sationtone 5HB) were added sequentially with stirring. Next, 150.0 g of deionized water was first added to stir to adjust the viscosity, followed by stirring to homogenize, followed by dilution with 244.7 g of deionized water. Subsequently, dispersion was performed with a SL-703 (BYK company) disperser until Hegman number 8+.

[ Example  5] electrodeposition Resin  Produce

140.2 g of diglycidyl ether (Kukdo Chemical, EPON 828), 59.7 g of bisphenol A and 9.8 g of propylene glycol monomethyl ether were charged into a reactor, heated to 140 ° C. under a nitrogen atmosphere, and 0.7 g of benzyldimethylamine was added thereto. . The reaction mixture was then spontaneously heated to about 185 ° C. and refluxed, followed by azeotropic removal of water present and left for 20-40 minutes. When the epoxy equivalent of the reaction mixture reached 900-950, the urethane curing agent was added with sufficient stirring and cooled until the temperature reached 100-110 ° C. with stirring for 30 minutes. Then, the reaction mixture was exothermic while adding 14.9 g of 73% methyl isobutyl ketone solution (KT22, Air Products, Inc.) and 16.8 g of diethanolamine, and the temperature was maintained at 120 ° C. Then, the reaction mixture was evacuated and the solvent was removed by vacuum recovery until the solid content was 96% by weight (-41 g), followed by 12.4 g of 70% methane sulfonic acid (BASF) and 332.6 g of deionized water. Added and dispersed. Then, 280 g of deionized water was slowly added to the dispersion and diluted to prepare an electrodeposition resin part having a solid content of 36% by weight.

At this time, the urethane curing agent used was prepared as follows.

382.6 g of polymeric methylenediphenyl diisocyanate (Dow Chemical, PAPI2940), 199.9 g of methyl isobutyl ketone, and 0.1 g of dibutyltin dilaurate were added to a reactor and heated to 30 ° C. under a nitrogen atmosphere. Next, 398 g of 2- (2-butoxyethoxy) ethanol was slowly added while maintaining the temperature at 60-65 ° C. The reaction mixture was then left at 65 ° C. for 90 minutes. After adding 19.4 g of trimethylol propane and heating to 110 ° C., the mixture was allowed to stand at this temperature for 3 hours, and the mixture was kept at 110 ° C. until no unreacted NCO- remained by infrared analysis. Was prepared.

[ Production Example  1 to 3 and Comparative Production Example  1] Electrodeposition Coating Composition

Each component was mixed with the composition of Table 2 below to prepare an electrodeposition coating composition.

ingredient Preparation Example 1 Preparation Example 2 Preparation Example 3 Comparative Production Example 1 Pigment part of Example 4 209 209 209 209 Electrodeposition resin part of Example 5 1294 1294 1294 1377 Solvent part
(Deionized water) 1455 1455 1455 1414

Curing additive part


Curing additive part 1 of Example 1 42 - - - Curing additive part 2 of Example 2 - 42 - - Curing additive part 3 of Example 3 - - 42 - Total (g) 3,000 3,000 3,000 3,000

[ Experimental Example  One]

Electrodeposition coating was performed by applying a constant voltage for 180 seconds to each of the electrodeposition coating composition of the Preparation Example and Comparative Preparation Example at 28 ° C. At this time, the electrodeposited coating specimens were steel sheets pretreated with zinc phosphate. Next, the electrodeposited specimen was placed in an oven at 150-160 ° C. and cured for 25 minutes to form a coating film. Then, physical properties were evaluated in the following manner, and the results are shown in Table 3 below.

1. Infiltration: (cm): A PVC tape is applied to both ends of two 10 × 30 cm specimens, fixed with transparent tape, 25 cm of the specimen is immersed in the electrodeposition paint composition, and the electrodeposition coating is carried out in the above-described manner. Measure the height painted on the back.

2. Roughness value (Ra): The surface roughness of the coating film was measured by using Taylor-Hobson surtronic3 +.

3. Mechanical properties (mm): After applying pressure using a 1.5 cm radius sphere on the painted specimen, measure the depth of the indentation of the specimen when the coating film is peeled off or broken.

4. Curability: Checking whether the surface change of the coating film or the electrodeposition coating composition is buried on the cloth by reciprocating the cloth immersed in methyl isobutyl ketone (MIBK) 10 times while applying a load of 1 kg.

X: Electrodeposition paint composition adheres a lot to cloth

(Triangle | delta): The electrodeposition coating composition is a little burying in cloth

(Circle): Electrodeposition coating composition does not adhere to cloth, but there exists a surface change of coating film

(Double-circle): Electrodeposition coating composition does not adhere to cloth, and there is no surface change of coating film

5. Corrosion resistance (mm): Test the coated specimen using a salt-fog apparatus for 1,000 hours, and then perform a peel-off test with a transparent tape to measure the peeling distance of the film.

division Preparation Example 1 Preparation Example 2 Preparation Example 3 Comparative Production Example 1 Coating thickness (㎛) 17 17 17 17 Internal penetration (cm) 24.5 24.8 25.0 22.8 Roughness value (Ra) 0.17 0.17 0.17 0.18 Mechanical property (mm) 8.5 8.5 8.5 8.5 Curable Curing temperature 150 ℃ ○ ○ ◎ × Curing temperature 160 ℃ ◎ ◎ ◎ ◎ Corrosion Resistance (mm) 1.1 0.8 0.8 1.2

Referring to Table 3, as the electrodeposition coating composition is applied to the electrodeposition coating composition to which the cationic urethane curing agent of the present invention is added, the curing property is ensured even at a relatively low temperature, and the coating property of the electrodeposition coating composition is excellent, and the corrosion resistance and strength are excellent. It can be confirmed that a coating film is formed.

Claims (11)

A cationic urethane curing agent obtained by neutralizing a reactant of a tertiary amine compound having a hydroxy group with an isocyanate compound with an acid neutralizer. The method according to claim 1,
The said tertiary amine compound is a cationic urethane hardening | curing agent obtained by reacting a primary amine compound or a secondary amine compound with a monoepoxide. The method according to claim 2,
The primary amine compounds are ethanolamine, 3-amino-1-propanol, amino-2-propanol, 2-amino-2-methyl-1-propanol, 2-amino-3-methyl-1-butanol, and 5- Cationic urethane curing agent is one or more selected from the group consisting of amino-1-pentanol. The method according to claim 2,
The secondary amine compound is a cationic urethane curing agent is one or more selected from the group consisting of 2-methylaminoethanol, 2-ethylaminoethanol, 3-methylamino-1-propanol, and 2-isopropylaminoethanol. The method according to claim 2,
The monoepoxide is glycidyl acrylate, glycidyl methacrylate, glycidyl acetate, glycidyl butyrate, glycidyl palmitate, glycidyl laurate, butyl glycidyl ether, 2-ethyl Cationic urethane curing agent which is at least one member selected from the group consisting of hexyl glycidyl ether, phenyl glycidyl ether, and P- (tertbutyl) phenyl glycidyl ether. The method according to claim 2,
Cationic urethane curing agent wherein the monoepoxide is a compound represented by the formula (1).
[Formula 1]

(In Formula 1, R ¹ and R ² are the same as or different from each other, and each independently an alkyl group having 1 to 10 carbon atoms.) The method according to claim 1,
The tertiary amine compound is 2-dimethylaminoethanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-diethylaminoethanol, 4-dimethylamino-1-butanol, 2-dimethylamino Cationic urethane curing agent which is at least one selected from the group consisting of 2-methylpropanol, and 4-dimethylamino-1-butanol. The method according to claim 1,
The isocyanate compound is 4,4'-methylenebis (phenylisocyanate), 4-methyl-1,3-phenylene diisocyanate, polymeric methylenediphenyl diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 2,4 , 6-triisopropylphenyl diisocyanate, diphenyl ether diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, tetramethyl xylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate And at least one selected from the group consisting of 2,4,4-trimethylhexamethylene diisocyanate. The method according to claim 1,
The acid neutralizer is a cationic urethane curing agent is at least one selected from the group consisting of acetic acid, lactic acid, formic acid, sulfonic acid, and methanesulfonic acid. The method according to claim 1,
The neutralization rate of the reactant and the acid neutralizer is defined by Equation 1 below,
Cationic urethane curing agent wherein the neutralization rate is 5 to 150%.
[Equation 1]
(Acid equivalent of acid neutralizer / amine equivalent of reactant) × 100 Electrodeposition resin part,
Pigment Part,
A hardening additive part containing the cationic urethane hardening | curing agent of any one of Claims 1-10, and
Electrodeposition coating composition containing a solvent part.