Electrodeposition coating composition

Abstract

The present invention provides an electrodeposition coating composition having excellent washability and bubble stability, wherein the electrodeposition coating composition comprises an emulsion resin composition and a pigment dispersion, the emulsion resin composition comprising an epoxy resin, a polyurethane curing agent, and a polyether-modified organosilicon compound.

Description

Technical Field

[0001] This invention relates to an electrodeposited coating composition that exhibits excellent washability and bubble stability. Background Technology

[0002] As a method to prevent corrosion of metallic materials, the surface of the metal is usually coated, and various coating methods are applied, such as brush coating, roller coating, electrodeposition coating, powder coating, and spray coating. Among these methods, electrodeposition coating is a widely used method because it has excellent coating performance and causes less environmental pollution. In particular, cationic electrodeposition coating can be performed continuously, making it advantageous for applications involving large objects to be coated.

[0003] To impart excellent processability, corrosion resistance, and coating appearance properties, electrodeposition coating compositions with various compositions have been proposed. For example, Korean Patent No. 10-0211079 discloses an electrodeposition composition comprising a non-gelling cationic resin derived from a polyepoxide, wherein the resin molecule contains active hydrogen groups selected from aliphatic hydroxyl, primary amino, and secondary amino groups, as well as cationic salt groups; and a fully end-capped polyisocyanate curing agent that is substantially free of free isocyanate groups.

[0004] However, typical electrodeposited coatings suffer from poor washability, which leads to poor stain or bubble stability. Therefore, there is a need to develop an electrodeposited coating composition that exhibits excellent washability and bubble stability, and can provide a coating film with superior appearance properties. Summary of the Invention

[0005] Technical issues

[0006] The present invention provides an electrodeposited coating composition that has excellent washability and bubble stability.

[0007] Technical solution

[0008] The present invention provides an electrodeposition coating composition comprising an emulsion resin composition and a pigment dispersion, wherein the emulsion resin composition comprises an epoxy resin, a polyurethane curing agent and a polyether-modified organosilicon compound.

[0009] Beneficial effects

[0010] This invention provides an electrodeposited coating composition exhibiting excellent washability and bubble stability. The electrodeposited coating composition of this invention possesses excellent washability, thus minimizing water stains generated during the electrodeposition coating process, while also exhibiting excellent bubble stability, thereby imparting an excellent appearance to the coating film to which the electrodeposited coating composition is applied. Attached Figure Description

[0011] Figure 1 The criteria for evaluating the washability of coatings are shown. Detailed Implementation

[0012] The invention will be described in detail below. However, the invention is not limited to the following description, and various modifications or selective combinations and uses of each component may be made if desired. Therefore, it should be understood that all variations, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included.

[0013] The “number-average molecular weight” or “weight-average molecular weight” used herein are measured by methods known in the art and can be measured, for example, by gel permeation chromatography (GPC). “Viscosity” is measured by methods known in the art and can be measured at room temperature (25°C) using, for example, a Gardner viscometer (bubble viscometer).

[0014] The electrodeposition coating composition of the present invention comprises an emulsion resin composition and a pigment dispersion, wherein the emulsion resin composition comprises an epoxy resin, a polyurethane curing agent, and a polyether-modified organosilicon compound. If desired, the electrodeposition coating composition of the present invention may also contain additives, such as pH adjusters, wetting agents, catalysts, plasticizers, and anti-pitting agents.

[0015] <Emulsion Resin Composition>

[0016] Epoxy resin

[0017] The emulsion resin composition of the electrodeposition coating composition of the present invention includes epoxy resin. Epoxy resin is the base resin (main resin) component that cures to form a coating film, and is used to impart properties such as adhesion and heat resistance to the formed coating film.

[0018] Examples of epoxy resins may include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alkyl-phenolnovelac type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, etc., any one of which may be used alone or in combination of two or more.

[0019] Epoxy resins can have an epoxy equivalent of 150 g / eq to 250 g / eq, for example, 180 g / eq to 200 g / eq. If the epoxy equivalent of the epoxy resin is less than the above range, the curability may be reduced due to poor crosslinking with the curing agent; if it is greater than the above range, the appearance characteristics may be reduced, such as roughening of the coating surface.

[0020] The viscosity (at 25°C) of epoxy resin can be from 10,000 cPs to 20,000 cPs, for example, from 11,000 cPs to 14,000 cPs. If the viscosity of the epoxy resin is less than the above range, the flexibility of the coating film may be reduced; if it is greater than the above range, the appearance properties may be reduced, such as roughening of the coating surface.

[0021] Based on 100 parts by weight of the emulsion resin composition, the epoxy resin content can be from 5 parts by weight to 20 parts by weight, for example, from 10 parts by weight to 14 parts by weight. If the epoxy resin content is less than the above range, the flexural strength may deteriorate; if it is greater than the above range, the water resistance may deteriorate.

[0022] polyurethane curing agent

[0023] The emulsion resin composition includes a polyurethane curing agent. The polyurethane curing agent is a component used to crosslink the base resin, thereby curing the base resin, and may include isocyanate-based compounds.

[0024] The isocyanate-based compound can be a monomeric isocyanate or a polymeric isocyanate. For example, the isocyanate-based compound can be a monomeric isocyanate such as methyl biphenyl diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diphenyl diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, terephthalic diisocyanate, diphenylmethane-4,4'-diisocyanate, triphenylmethane-4,4',4”-triisocyanate or mixtures thereof, or a polymeric isocyanate such as polymethylene polyphenyl isocyanate.

[0025] Polyurethane curing agents may include isocyanate-based compounds capped with end-capping agents such as alcohols. In this case, the isocyanate groups (-NCO) contained in the isocyanate-based compound can be prevented from reacting with active hydrogen at room temperature, and their tendency to self-polymerize can be prevented. For example, polyurethane curing agents may include isocyanate-based compounds capped with linear alcohols containing three or more ether groups (-O-). Linear alcohols containing three or more ether groups (-O-) may include one or more of triethylene glycol monobutyl ether and tetraethylene glycol monobutyl ether.

[0026] The NV (Noise, Viscosity, and Variation) of the polyurethane curing agent can be 75% to 85%, for example, 79% to 81%; the viscosity (at 25°C) can be 500 cPs to 6000 cPs, for example, 1000 cPs to 4000 cPs; and the NCO (Natural Carbonate) content can be 0.5% or lower, for example, 0.2% or lower. If the NV of the polyurethane curing agent is less than the above range, curing properties may decrease, thus corrosion resistance may deteriorate; if it is greater than the above range, resin storage performance may decrease. If the viscosity of the polyurethane curing agent is less than the above range, internal coating performance may deteriorate; if it is greater than the above range, high-build coating may not be formed. If the NCO content of the polyurethane curing agent is greater than the above range, uncured NCO may remain, potentially reducing resin stability.

[0027] Based on 100 parts by weight of the emulsion resin composition, the content of the polyurethane curing agent can be from 10 parts by weight to 20 parts by weight, for example, from 13 parts by weight to 18 parts by weight. If the content of the polyurethane curing agent is less than the above range, the curing properties may be weaker, and corrosion resistance may become a problem; if it is greater than the above range, an over-deposited electrodeposited coating may occur.

[0028] Polyether-modified organosilicon compounds

[0029] The emulsion resin composition contains a polyether-modified organosilicon compound. The polyether-modified organosilicon compound is a high-molecular-weight material used to increase the surface energy of the electrodeposited coating, thereby improving washability and bubble stability.

[0030] Polyether-modified organosilicon compounds possess polyether groups as hydrophilic groups and polydialkylsiloxane groups as hydrophobic groups. Due to this structure, organosilicon has low surface tension energy. Therefore, by reducing the contact angle of water on the electrodeposited coating surface and increasing the surface energy, water diffuses more widely on the electrodeposited coating surface, making it easier for fixed water to accumulate and thus removing water.

[0031] Polyether-modified organosilicon compounds are compounds in which a portion of the alkyl group of a polydialkylsiloxane is replaced by a group having a polyoxyethylene group. The alkyl group contained in the polydialkylsiloxane can be an alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, phenyl, etc. Examples of polydialkylsiloxanes include polydimethylsiloxane, methylethylsiloxane-dimethylsiloxane copolymer, methylphenylsiloxane-dimethylsiloxane copolymer, etc. Examples of polyoxyethylene groups include polyethylene oxide, polyethylene oxide, polyethylene oxide-polyoxypropylene, etc. Examples of substituents having a polyoxyethylene group include hydroxy(polyoxyethylene)propylene, methoxy(polyoxyethylene)propylene, ethoxy(polyoxyethylene)propylene, hydroxypolyoxyethylene, methoxypolyoxyethylene, ethoxypolyoxyethylene, and polyoxyethylene, etc.

[0032] Polyether-modified organosilicon compounds may have a hydrophilic-lipophilic balance (HLB) of 9 to 14, for example 10 to 13, a number average molecular weight of 3000 g / mol to 15000 g / mol, for example 5000 g / mol to 12000 g / mol, and a propylene oxide (PO) content of 5 wt% to 50 wt%, for example 10 wt% to 40 wt%.

[0033] If the HLB of the polyether-modified organosilicon compound is less than the above range, it may produce oil due to the large number of polydialkylsiloxane groups and high hydrophobicity. If it is greater than the above range, it may produce oil due to the large number of polyether groups.

[0034] High hydrophilicity can lead to the generation of numerous bubbles. If the number-average molecular weight of the polyether-modified silicone compound is less than the above range, the surface energy may not increase effectively, resulting in poor anti-foaming performance. If it is greater than the above range, dispersion may be difficult, potentially reducing appearance properties or causing oil buildup. If the PO content of the polyether-modified silicone compound is less than the above range, numerous bubbles may be generated, potentially resulting in insufficient improvement in washability. If it is greater than the above range, the bubble removal effect may be excellent, but oil buildup may occur.

[0035] Based on 100 parts by weight of the emulsion resin composition, the content of the polyether-modified silicone compound can be from 0.01 parts by weight to 5 parts by weight, for example, from 0.01 parts by weight to 2 parts by weight, or even from 0.03 parts by weight to 1 part by weight. If the content of the polyether-modified silicone compound is less than the above range, the effect of improving washability may be insufficient; if it is greater than the above range, the anti-foaming performance or appearance may deteriorate.

[0036] Based on the total weight of the electrodeposited coating composition, the content of the polyether-modified silicone compound can be from 0.01% to 0.5% by weight. If the content of the polyether-modified silicone compound is less than the above range, the effect of improving washability may be insufficient; if it is greater than the above range, the anti-foaming performance or appearance may deteriorate.

[0037] polyols

[0038] The emulsion resin composition may also contain polyols. Polyols can help extend the chains of the epoxy resin, which serves as the base resin, to impart flexibility to the coating film and enhance water dispersibility, thereby improving processability and the appearance of the coating film.

[0039] As a polyol, a compound containing two or more hydroxyl groups can be used. For example, polyols may include ethylene glycol, propylene glycol, butanediol, bisphenol A, ethoxylated bisphenol A (BPA), bisphenol A-ethylene oxide adduct, glycerol, trimethylolpropane, etc., and any of these can be used alone or in combination of two or more.

[0040] The weight-average molecular weight of the polyol can be from 200 g / mol to 300 g / mol, for example, 220 g / mol to 280 g / mol, and the epoxy equivalent can be from 100 g / eq to 200 g / eq, for example, 130 g / eq to 170 g / eq. If the weight-average molecular weight of the polyol is less than the above range, the appearance may be worse; if it is greater than the above range, the internal coating performance may be reduced. If the epoxy equivalent of the polyol is less than the above range, the rust prevention performance may be reduced; if it is greater than the above range, the appearance may be worse.

[0041] Based on 100 parts by weight of the emulsion resin composition, the polyol content can be from 1 part by weight to 10 parts by weight, for example, from 3 parts by weight to 6 parts by weight. If the polyol content is less than the above range, the effect of extending the epoxy resin chain may be reduced, and the appearance of the coating film may become rough. If it is greater than the above range, the internal coating performance may be deteriorated.

[0042] amine compounds

[0043] The emulsion resin composition may also contain amine compounds. Amine compounds are used to terminate the epoxy resin reaction and extend the chain.

[0044] Amine compounds can be commonly used in electrodeposition resin compositions. For example, amine compounds can be primary amines, secondary amines, ketimine derivatives obtained by reacting primary amines with ketone compounds, or mixtures thereof. Amine compounds can be monoamine compounds, diamine compounds, triamine compounds, tetraamine compounds, or mixtures thereof, and can be, for example, diethanolamine, methyl ethylamine, dimethylpropylene diamine, benzylamine, n-butylamine, aniline, cyclopentylamine, cyclohexylamine, 2-aminophenol, 2-bromoaniline, ethylenediamine, hexamethylenediamine, aminoethylethanolamine, N-methylethanolamine, benzyl dimethylamine, ketimine, diketimine, diethylamine, diethylenetriamine, triethylenetetramine, butanolamine, or mixtures thereof.

[0045] Based on 100 parts by weight of the emulsion resin composition, the content of the amine compound can be from 1 part by weight to 4 parts by weight, for example, 2 parts by weight to 3 parts by weight. If the content of the amine compound is less than the above range, the internal coating performance of the coating film may deteriorate; if it is greater than the above range, the particle size may increase, thereby deteriorating the storage performance, water dispersibility, and appearance characteristics.

[0046] additive

[0047] The emulsion resin composition may also contain additives such as reaction catalysts, plasticizers, neutralizers, anti-pitting agents, edge covering additives, etc.

[0048] Neutralizing agents are used to neutralize the acidity of epoxy resins to adjust the pH value of the electrodeposition resin composition; alkyl sulfonic acids (e.g., methane sulfonic acid) can be used. Anti-pitting agents and edge-covering additives are used to enhance the oil resistance of the electrodeposition resin composition and adjust its flowability; microgels can be used. Ethyltriphenyl potassium bromide can be used as a reaction catalyst, and ethoxylated bisphenol A can be used as a plasticizer.

[0049] Additives may be added appropriately within the range of amounts known in the art, for example, based on 100 parts by weight of the emulsion resin composition, they may be included in amounts from 0.1 parts by weight to 10 parts by weight.

[0050] Pigment Dispersions

[0051] Dispersion resin

[0052] The pigment dispersion of the electrodeposited coating composition of the present invention comprises a dispersion resin. The dispersion resin is used to improve the wetting properties of the pigment in order to disperse the pigment.

[0053] The dispersing resin may include amine-modified epoxy resin. The NV (noise ratio) of the amine-modified epoxy resin may be 51% to 60%, for example 53% to 55%, and the viscosity (at 25°C) may be 1000 cPs to 8000 cPs, for example 3000 cPs to 6000 cPs. If the NV content of the epoxy resin is less than the above range, the pigment dispersibility may decrease; if it is greater than the above range, the coating yield may decrease due to the high viscosity.

[0054] Based on 100 parts by weight of pigment dispersion, the content of dispersing resin can be from 1 part by weight to 10 parts by weight, for example, from 5 parts by weight to 10 parts by weight. If the content of dispersing resin is less than the above range, the pigment dispersibility may decrease. If it is greater than the above range, the coating yield may decrease.

[0055] pigment

[0056] The pigment dispersion contains a pigment. Pigments commonly used in the art can be used as pigments. For example, inorganic pigments such as titanium dioxide, zinc oxide, zinc sulfide, kaolin, clay, calcium carbonate, talc, silica, iron oxide, lead chromate, cadmium, chromium oxide, carbon black, zinc chromate, strontium chromate, zinc phosphate, phosphates, silicates, barium sulfate, etc., can be used alone or in combination of two or more.

[0057] Based on 100 parts by weight of pigment dispersion, the pigment content can be from 30 parts by weight to 50 parts by weight, for example, from 35 parts by weight to 45 parts by weight. If the pigment content is less than the above range, the opacity relative to the object to be coated may be reduced; if it is greater than the above range, the appearance of the coating and the processability during the electrodeposition process may be reduced.

[0058] additive

[0059] Pigment dispersions may also contain additives, such as curing catalysts, pH adjusters, dispersants, etc.

[0060] Curing catalysts can improve the curability of pigment dispersions or electrodeposited coatings containing pigment dispersions. As curing catalysts, tin-containing compounds, bismuth-containing compounds, and mixtures thereof can be used. For example, tin-containing compounds such as dibutyltin oxide, dibutyltin dilaurate, dibutyltin chloride, dioctyltin chloride, and dioctyltin oxide can be used; bismuth-containing compounds in which Bi₂O₃ or Bi(OH)₂ is mixed with acids such as lactic acid, acetic acid, formic acid, dimethylolpropionic acid (DMPA), and methanesulfonic acid (MSA); and mixtures thereof.

[0061] Acids such as acetic acid can be used as pH adjusters, and wetting agents can be used as dispersants.

[0062] Based on 100 parts by weight of the pigment dispersion, the content of the curing catalyst can be from 10 parts by weight to 50 parts by weight, for example, from 30 parts by weight to 40 parts by weight. Additives other than the curing catalyst described above can be appropriately added within the range of contents known in the art; for example, based on 100 parts by weight of the pigment dispersion, they can be included in amounts from 0.1 parts by weight to 10 parts by weight.

[0063] The electrodeposition coating composition of the present invention comprises the above-described emulsion resin composition, pigment dispersion, and water. For example, based on 100 parts by weight of the electrodeposition coating composition, it comprises 40 to 60 parts by weight, for example 45 to 55 parts by weight of the emulsion resin composition, 2 to 8 parts by weight, for example 4 to 6 parts by weight of the pigment dispersion, and 40 to 60 parts by weight, for example 45 to 55 parts by weight of water.

[0064] If the content of the emulsion resin composition is less than the above range, the internal coating performance may be reduced; if it is greater than the above range, the curing performance may be reduced, and thus the corrosion resistance may decrease. If the content of the pigment dispersion is less than the above range, the curing performance may be reduced, and thus the corrosion resistance may decrease; if it is greater than the above range, the internal coating performance may decrease.

[0065] Methods of implementing the present invention

[0066] The invention will be described in more detail below with reference to embodiments. However, the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0067] [Preparation of Emulsion Resin Precompositions]

[0068] [Preparation Example 1]

[0069] The emulsion resin pre-composition of Example 1 was prepared according to the composition described in Table 1 below.

[0070] [Table 1]

[0071] Components (parts by weight) Preparation Example 1 Epoxy resin 130.8 polyurethane curing agent 166.5 Bisphenol A (BPA) 55.1 Ethoxylated Bisphenol A 17.6 monoethanolamine 11.6 diketimine 15.9 Ethyltriphenyl potassium bromide 0.13 Methanesulfonic acid (70%) 14.8 Deionized water 609 Solvent vacuum recovery -21.6

[0072] Epoxy resin: Bisphenol A diglycidyl ether (epoxy equivalent 188 g / eq, viscosity (25℃) 12500 cPs)

[0073] Polyurethane curing agent: A polyurethane curing agent prepared from 380.4 parts by weight of polymeric methylene diphenyl diisocyanate (PAPI2940, Dow Chemical), 200 parts by weight of methyl isobutyl ketone, 400.4 parts by weight of 2-(2-butoxyethoxy)ethanol and 19.2 parts by weight of trimethylolpropane.

[0074] Diketimine: 73% diketimine in methyl isobutyl ketone solution, wherein diethylenetriamine is capped with methyl isobutyl ketone.

[0075] [Preparation of Emulsion Resin Compositions]

[0076] [Experimental Examples 1 to 13]

[0077] The emulsion resin compositions for each experimental example were prepared according to the compositions described in Tables 2 and 3 below.

[0078] [Table 2]

[0079]

[0080] [Table 3]

[0081]

[0082] Emulsion Resin Precomposition: Preparation of the Emulsion Resin Precomposition of Example 1

[0083] Polyether-modified organosilicon compound 1: HLB 12, number average molecular weight (Mn) 8000, propylene oxide (PO) content 30%.

[0084] Polyether-modified organosilicon compound 2: HLB 10, Mn 5000, PO content 25%

[0085] Polyether-modified organosilicon compound 3: HLB 13, Mn 11000, PO content 35%

[0086] Polyether-modified organosilicon compound 4: HLB 6, Mn 2800, PO content 30%

[0087] Polyether-modified organosilicon compound 5: HLB 12, Mn 18000, PO content 35%

[0088] Polyether-modified organosilicon compound 6: HLB 8, Mn 6000, PO content 60%.

[0089] Polyether-modified organosilicon compound 7: HLB 17, Mn 3500, PO content 30%.

[0090] Organic compound: Polyacrylate copolymer (HLB 12, Mn 750, PO content 20%)

[0091] [Preparation of Pigment Dispersions]

[0092] [Preparation Example 2]

[0093] The pigment dispersion of Example 2 was prepared according to the composition described in Table 4 below.

[0094] [Table 4]

[0095] Components Content (parts by weight) Dispersion resin 77 carbon black 1 Titanium dioxide 280 Curing catalyst 355 Aluminum silicate 140 Acetic acid (30% dilution) 3 Surfynol 107L (EVONIK) 10 Deionized water 134

[0096] Dispersion resin: Amine-modified epoxy resin (NV 54%, viscosity (25℃) 4800 cPs)

[0097] Curing catalyst: Dibutyltin oxide (DBTO) slurry (303 parts by weight of dispersion resin, 193 parts by weight of DBTO, and 504 parts by weight of deionized water)

[0098] [Preparation of Electrodeposited Coating Compositions]

[0099] 467g of the emulsion resin from each experimental example and 480g of deionized water were mixed and stirred, and 53g of the pigment dispersion from Example 2 was gradually added to prepare a cationic electrodeposition coating composition with a solids content of 20%. The cationic electrodeposition coating composition was allowed to stand and stirred for 24 hours, and then electrodeposited for 3 minutes at a temperature of 28°C and a DC voltage of 220V. As a sample, a cold-rolled steel sheet with zinc phosphate surface was used, and the coated object was cured in an oven at 160°C for 25 minutes. The performance of the dried coating was evaluated by the following methods, and the evaluation results are shown in Table 5 below.

[0100] Illuminance value

[0101] The illuminance value was measured using a lux meter with a Cot-off of 2.5 mm. The illuminance value is a numerical value representing the height deviation within a certain distance; the smaller the value, the better the appearance.

[0102] pit formation

[0103] Use the naked eye to identify whether there is oil with engraved shapes.

[0104] Water washability

[0105] Immediately after electrodeposition, the coating is cured at 160°C for 25 minutes without cleaning to identify any residual electrodeposition solution contaminants on the coating. Evaluation criteria are as follows. Figure 1 As shown.

[0106] bubble stability

[0107] After introducing 200 ml of electrodeposition coating solution into a 500 ml mass bottle, the cap was placed to cover the top of the cylinder, and then the cylinder was rotated up and down 20 times at a rate of 1 time per second to determine the amount of bubbles generated immediately after rotation and the amount of bubbles remaining after 2 minutes.

[0108] [Table 5]

[0109]

[0110]

[0111] As shown in Table 5 above, the electrodeposited coatings of each of Experimental Examples 1 to 7, which contain the polyether-modified organosilicon compound according to the present invention, exhibited excellent overall performance in the measured items. On the other hand, the electrodeposited coating of Example 8, which does not contain the polyether-modified organosilicon compound, exhibited poor washability. The electrodeposited coatings of each of Experimental Examples 9 to 12, in which the performance of the polyether-modified organosilicon compound is not within the scope of the present invention, all exhibited poor washability. In particular, in the case of Experimental Example 9, where the polyether-modified silicone compound has an HLB and number-average molecular weight lower than the scope of the present invention, it exhibited a large number of pits; in the case of Example 10, where the polyether-modified organosilicon compound has a number-average molecular weight higher than the scope of the present invention, it exhibited high illuminance (poor appearance); in the case of Example 11, where the polyether-modified organosilicon compound has an HLB lower than the scope of the present invention, it exhibited pits; and in the case of Example 12, where the polyether-modified organosilicon compound has an HLB higher than the scope of the present invention, it exhibited poor bubble stability.

[0112] Furthermore, the electrodeposited coating of Experimental Example 13 (in which polyacrylate copolymers were used instead of polyether-modified organosilicon compounds) exhibited poor bubble stability.

[0113] Industrial availability

[0114] This invention provides an electrodeposited coating composition exhibiting excellent washability and bubble stability. The electrodeposited coating composition of this invention possesses excellent washability, thus minimizing water stains generated during the electrodeposition coating process, while also exhibiting excellent bubble stability, thereby imparting an excellent appearance to the coating film to which the electrodeposited coating composition is applied.

Claims

1. An electrodeposition coating composition comprising: An emulsion resin composition comprising an epoxy resin, a polyurethane curing agent, and a polyether-modified organosilicon compound; and Pigment dispersion, The polyether-modified organosilicon compound has a hydrophilic-lipophilic balance (HLB) of 10 to 13, a number-average molecular weight of 3000 g / mol to 15000 g / mol, and a propylene oxide (PO) content of 10 wt% to 40 wt%.

2. The electrodeposition coating composition according to claim 1, wherein the content of the polyether-modified organosilicon compound is from 0.01% to 0.5% by weight, based on the total weight of the electrodeposition coating composition.

3. The electrodeposition coating composition according to claim 1, wherein the epoxy resin has an epoxy equivalent of 150 g / eq to 250 g / eq and a viscosity (25°C) of 10000 cPs to 20000 cPs.

4. The electrodeposited coating composition according to claim 1, wherein the polyurethane curing agent has an NV of 75% to 85%, a viscosity (25°C) of 500 cPs to 6000 cPs, and an NCO content of 0.5% or less.

5. The electrodeposition coating composition according to claim 1, wherein the pigment dispersion comprises a dispersion resin and a pigment, the dispersion resin comprising an amine-modified epoxy resin having an NV of 51% to 60% and a viscosity (25°C) of 1000 cPs to 8000 cPs.

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