KR20010066312A - polyepoxide-polyoxyalkyleneamine water-dispersable resin containing hydroxyl group and cathodic electrodeposition coating composition containing the same - Google Patents

Abstract

PURPOSE: Provided is a water-dispersable polyepoxide-polyoxyalkylene amine resin containing a hydroxy group. And a cationic electrodepositing paint composition containing the same is also provided, which shows excellent adhesibility to the top coating when being coated, and has tolerance to crater and pin hole and also has heat-stability. CONSTITUTION: The water-dispersable polyepoxide-polyoxyalkylene amine resin is prepared by reacting 1 equivalent of a polyepoxide-polyalkanol mono-amine derivative represented by the formula (1) with 1.05-3.0 equivalents of a polyoxyalkylene diamine, which has a molecular weight of 150-3500 and is represented by the formula (2), or a polyoxyalkylene mono-amine represented by the formula (3) at 50-150 deg.C in the presence of a solvent or not. In the formula (1), R1 and R2 are independently the same or different from each other wherein at least one of R1 and R2 is C1-4 alkyl radical containing a hydroxy group, and R3 is C21-57 alicyclic or an aromatic hydrocarbon radical containing an ether group. In the formula (2), two Rs are independently the same or different from each other and are selected from the group consisting of hydrogen and C1-6 alkyl radical, and n is an integer of 1-50. In the formula (3), two Rs are independently the same or different from each other and are selected from the group consisting of hydrogen and C1-6 alkyl radical, and n is an integer of 1-50. The cationic electrodepositing paint composition comprises: (i) 2-5 wt.% of the water-dispersable polyepoxide-polyoxyalkylene amine resin containing a hydroxy group; (ii) 32-38 wt.% of a cationic resin which is able to electrodeposit a cation; (iii) 1-2 wt.% of a plasticizer; (iv) 45-50 wt.% of deionized water; and (iv) the balance of other components.

Description

Polyepoxide-polyoxyalkyleneamine water-dispersable resin containing hydroxyl group and cathodic electrodeposition coating composition containing the same}

The present invention relates to a polyepoxide-polyoxyalkyleneamine water-dispersion resin containing a hydroxyl group and a cationic electrodeposition coating composition containing the same.

Electrodeposition coating means that the polymer having a charge moves to the electrode of the opposite charge under the action of direct current, in which the change of pH causes the polymer to precipitate due to the electrolysis of water, thereby forming a non-conductive coating film. This electrodeposition method is of increasing importance because it provides higher adhesion efficiency, significant anti-corrosion, and low environmental pollution compared to non-electrophoretic means.

In the field of electrodeposition, anion electrodeposition method was initially used, which means electrodeposition using the anode to be coated. However, the cationic electrodeposition method was introduced in 1972 to achieve better rust resistance. Since then, cationic electrodeposition has steadily gained popularity, making it the main electrodeposition method of today. More than 80% of all automobiles produced worldwide form undercoats by cationic electrodeposition.

The most frequent problem in applying electrodeposition paint is the occurrence of defects in the coating film. Representative coating defects include pinhols and cratering craters. Such coating defects are known to be due to various causes such as local electric discharge due to the introduction of impurities into the electrodeposition bath or hydrogen gas generated during cationic electrodeposition.

In order to solve the said coating film defect, the resin in which the polyoxyalkylene group was introduce | transduced was reported to be effective. For example, US Pat. Nos. 4,420,574 and 4,432,850 disclose that epoxy amine water dispersion resins incorporating polyoxyalkylene diamines are effective in preventing such coating defects. However, this technique has been reported to have a disadvantage in that it is difficult to produce a stable aqueous dispersion due to the lack of hydrophilic groups, and poor adhesion to alkyd modified tops. In order to improve the adhesion with this top coat, US Pat. No. 5,348,578 describes a method for preparing a urethane reactant in which an amine alkylene oxide diol is introduced. However, the above technique has a disadvantage in that the polyisocyanate decomposes during curing of the electrodeposition-coated coating film and becomes yellow in compatibility with the epoxy-amine main resin.

Accordingly, the present inventors have conducted extensive research to solve the above problems, and when applying the polyepoxide-polyoxyalkyleneamine water-dispersion resin containing a hydroxyl group at the resin end to the electrodeposition paint, It has been found to be resistant to pinholes and cratering, to improve the thermal stability of aqueous products, to solve yellowing problems in alkyd modified top coats, and to improve problems such as lack of adhesion to top coats. The present invention has been completed based on this.

Accordingly, an object of the present invention is to provide a water-dispersible resin which can induce a coating film resistant from pinholes and cratering, and improves heat storage stability and adhesion to tops.

Another object of the present invention to provide a cationic electrodeposition coating composition using the water-dispersible resin.

Polyepoxide-polyoxyalkyleneamine water-dispersion resin containing a hydroxyl group of the present invention for achieving the above object is a polyepoxide-polyalkanol represented by the following formula (1) in the presence or absence of a solvent Reacting 1 equivalent of the monoamine derivative with 1.05 to 3.0 equivalents of the polyoxyalkylene diamine represented by the following formula (2) and / or the polyoxyalkylene monoamine represented by the following formula (3) having a molecular weight of 150 to 3500 at 50 to 150 ° C. It consists of

Here, R ₁ and R ₂ may be the same or different from each other, at least one of R ₁ and R ₂ is an alkyl radical having 1 to 4 carbon atoms containing a hydroxyl group, R ₃ is 21 to carbon atoms containing an ether group 57 alicyclic or aromatic hydrocarbon radical.

Here, R may be the same or different from each other, is selected from the group consisting of hydrogen or alkyl radicals of 1 to 6 carbon atoms, n is an integer of 1 to 50.

Here, R may be the same or different from each other, is selected from the group consisting of hydrogen or alkyl radicals of 1 to 6 carbon atoms, n is an integer of 1 to 50.

The cationic electrodeposition coating composition of the present invention for achieving the above another object is 2 to 5% by weight of a polyepoxide-polyoxyalkyleneamine water-containing resin containing a hydroxyl group of the present invention, 32 to cation electrodepositable cation resin 38% by weight, 1 to 2% by weight of plasticizer, 50 to 45% by weight of deionized water and the remainder are other components.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a polyepoxide-polyoxyalkylene amine water-dispersion resin containing a hydroxyl group and a cationic electrodeposition coating composition containing the same, wherein the water-dispersion resin is first polyepoxide-polyalkanol monoamine After the derivative is prepared, it is prepared by reacting the derivative with polyoxyalkyleneamine.

First, the polyepoxide-polyalkanol monoamine derivative is prepared by reacting 1 equivalent of polyepoxide with 0.2-0.5 equivalents of polyalkanol monoamine represented by the following Chemical Formula 4 in the presence or absence of a solvent, and Molecular weight and viscosity can be controlled preferably.

Here, R ₁ and R ₂ may be the same or different from each other, at least one of R ₁ and R ₂ is an alkyl radical having 1 to 4 carbon atoms containing a hydroxyl group.

In this case, when the equivalent ratio of the polyalkanol monoamine to the polyepoxide is less than 0.2, a problem may occur in that the high molecular weight increases in the reaction with the polyoxyalkylene amine, which is the next reaction, to lower the appearance of the coating film, and 0.5 If exceeded, a problem may occur in which the breakdown voltage due to the increase in the low molecular weight may drop.

The polyepoxides used in the present invention are well known in US Pat. Nos. 2,467,171, 2,615,007, 2,716,123, 3,053,855, and 3,075,999. The epoxy functional groups of the polyepoxide have at least one, preferably at least 1.4 and most preferably at least two epoxy groups per molecule. Examples of preferred polyepoxides are polyglycidyl ethers of polyphenols or polyglycidyl ethers of aromatic polyols such as bisphenol A and the like. Such polyepoxides can be prepared by ether reaction of an epihalohydrin or diepihalohydrin such as epichlorohydrin or dichlohydrin with an aromatic polyol in the presence of alkali. Examples of other polyepoxides can be derived from noblock resins or polyphenol resins. On the other hand, an increase in the molecular weight of the polyglycidyl ether of the polyhydric material is possible by the reaction of the polyglycidyl ether of the aromatic diol with a polyol capable of reacting with an epoxide group. At this time, examples of the applicable polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, bisphenol-A and the like.

Preferred polyalkanol monoamines used in the preparation of the polyepoxide-polyalkanol monoamine derivatives of the invention are secondary amines containing at least one hydroxyl group in the molecule.

The reaction temperature of the reaction is 30 to 80 ° C, preferably 40 to 60 ° C, if the temperature is less than 30 ° C.

The reaction can be carried out in the presence or absence of a solvent, the solvent is selected from the group consisting of hydrocarbons, ethers, alcohols and ether-alcohols, the amount of which is preferably 20 to 50% by weight relative to the total reaction mixture It is suitable.

The polyepoxide-polyalkanol monoamine derivative thus prepared has from 0.5 to 1 epoxy functional group per mole and at least one hydroxyl group.

Preferred polyoxyalkylene amines that react with the epoxy groups of the polyepoxide-polyalkanol monoamine derivatives are diamines or monoamines, represented by the following formulas (2) and (3), respectively.

Formula 2

Here, R may be the same or different from each other, is selected from the group consisting of hydrogen or alkyl radicals of 1 to 6 carbon atoms, n is an integer of 1 to 50.

Formula 3

Here, R may be the same or different from each other, is selected from the group consisting of hydrogen or alkyl radicals of 1 to 6 carbon atoms, n is an integer of 1 to 50.

The polyoxyalkylene monoamine and polyoxyalkylene diamine can be used alone or in combination. The use of polyoxyalkylene diamines yields linear polymers, and the use of polyoxyalkylene monoamines yields polymers grafted with polyoxyalkylene groups. In addition, since the polyoxyalkylene monoamine is a monovalent functional group, the polyoxyalkylene monoamine has the advantage of low gelation during the reaction with epoxy and easy molecular weight control. Methods for preparing such polyoxyalkylene amines are well known in US Pat. No. 3,236,895.

In addition to the polyoxyalkylene monoamines and diamines described above, polyamine derivatives may be used, for example, a poly represented by the following Chemical Formula 5 prepared by a hydrogenation reaction after reacting a polyoxyalkylene amine with acrylonitrile Oxyalkylene polyamine derivatives may also be used.

Wherein R may be the same or different and is selected from hydrogen or an alkyl radical of 1 to 6 carbon atoms, and n is an integer from 1 to 50.

The molecular weight (number average molecular weight) of the polyoxyalkylene amine of this invention is 150-3500, Preferably it is 700-2500.

The active hydrogen equivalent of polyoxyalkylene amine to epoxy of the polyepoxide-polyalkanol monoamine derivative of the present invention is 1.05 to 3.0.

The reaction temperature of the said reaction is 50-150 degreeC, Preferably it is 90-130 degreeC.

The reaction proceeds in the presence or absence of a solvent, and examples of the solvent that can be used are those that do not react with epoxy groups and amines, such as hydrocarbons, ethers, alcohols, ether-alcohols and the like. At this time, the amount of solvent used is 30 to 50% by weight based on the total reaction mixture.

The polyepoxide-polyoxyalkylene amine resin of the present invention prepared by the above reaction has almost no epoxy functional groups (ie, epoxy equivalent of 10,000 or more), and has at least one hydroxyl group at the terminal of the polymer structure. there is. Dispersion stability can be ensured, it is characterized by improving the adhesion to the top.

The hydroxyl group-containing polyepoxide-polyoxyalkylene amine water dispersion resin of this invention can be disperse | distributed to an aqueous solution phase by partial neutralization with an acid. Suitable acids that can be used include organic acids such as formic acid, lactic acid, dimethylolpropionic acid and acetic acid. The reaction product is usually neutralized by about 30% at the total theoretical neutralization degree. The reaction product is partially neutralized with acid and dissolved or dispersed in aqueous solution. The average particle diameter of dendritic phase is 10 microns or less, Preferably it is 5 microns or less. The concentration of the dendritic phase in the aqueous medium depends on the convenience of the end use of the dispersion and is not fixed.

The cationic electrodeposition coating composition of the present invention comprises 2 to 5% by weight of the polyepoxide-polyoxyalkyleneamine water-dispersible resin containing the hydroxyl group, 32 to 38% by weight of the cationic electrodepositable cation resin, and 1 to 2 weight of the plasticizer. % And 45-50% by weight of deionized water. At this time, if the amount of the water-dispersible resin of the present invention contained in the cationic electrodeposition coating composition is less than 2% by weight, there is a problem inferior in the crater resistance, and if it exceeds 5% by weight, the adhesion with the top coat is insufficient. Problems may arise.

Generally, it is useful to use the water-dispersible resin together with the cation electrodepositable coating composition, but it is also applicable to an aqueous coating composition other than the cation electrodepositable coating composition. Examples of cationic electrodepositable paints include amine salt group resins that neutralize polyepoxides and amine reactants with acids, as described in US Pat. No. 4,031,050. Usually amine salt group containing resins are used in admixture with blocked isocyanate curing agents.

The hydroxyl group-containing polyepoxide-polyoxyalkylene amine water-dispersible resin of the present invention and the cationic electrodepositable resin are bonded by simple mixing under light stirring. Preferably, the modified cation adduct and the electrodepositable resin have a solids content of 0.5 to 50% in the aqueous state. Optional ingredients such as pigments, co-solvents and plasticizers and other ingredients such as preservatives, curing agents and catalysts can be mixed upon or prior to mixing the two resins and diluted with deionized water to control the resin solids for cationic electrodeposition. do.

The aqueous medium may contain, in addition to water, a coalescing solvent. Useful flocculants are hydrocarbons, alcohols, esters, ethers and ketones. Preferred flocculants include alcohols, polyols and ketones. Specific flocculating solvents include isopropanol, butanol, 2-ethyl hexanol, isophorone, 4-methoxy-pentanone, ethylene and propylene glycol and mono ethyl, monobutyl and monohexyl ethers of ethylene glycol, and the like. The amount of flocculant solvent is generally about 0.01 to 25% by weight, preferably about 5% by weight, based on the weight of the aqueous medium.

When the above-mentioned aqueous dispersion is used for electrodeposition, the surface to be painted is the cathode, and the aqueous dispersion is placed in contact with the electrically conductive cathode and the electrically conductive anode. When sufficient voltage is given between the electrodes after contact with the aqueous acid solution, the adhesive film of the coating composition becomes a negative electrode. Electrodeposition conditions are generally similar to those for depositing other types of coatings. The voltage used can vary, for example, from as low as 1 volt to as high as thousands of volts, but typically between 50 and 500 volts. Current densities are usually 0.5-5 amps / feet ² and tend to decrease during electrodeposition, which means that an insulating film is formed. The coating compositions of the present invention can be used on a variety of electrically conductive substrates, in particular metals such as steel, aluminum, copper, magnesium and the like and materials coated with conductive carbon. It is coated by electrodeposition and then cured by heat treatment at a temperature of 90 to 270 ° C. for about 1 to 40 minutes.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

The hydroxyl containing polyepoxide-polyoxyalkylene amine compounds useful in the present invention were prepared as follows in the composition of Table 1 below.

Reactant Parts by weight (g) 2-butoxyethanol 303.9 N8010 ¹ 314.9 Diethanolamine 33.9 Jeffamine D-2000N ² 301.2 2-butoxyethanol 46.1 Lactic acid 33.9 Deionized water 1566.1

1 is an epoxy resin having an epoxy equivalent of 480 obtained by reacting bisphenol-A and epichlorohydrin available from Koryo Chemical.

2 is a polyoxyalkylene diamine having a molecular weight of 2,000 available from Huntman, USA.

303.9 g of 2-butoxyethanol is introduced into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, and the temperature is increased to 85 ° C. Insert 314.9 g of N8010 to dissolve completely and cool to 45 ° C. When the appropriate temperature is reached, 33.9 g of diethanolamine is added thereto and maintained at 48 ° C. for 4 hours. At this time, when the epoxy equivalent was measured to reach 2,000, 301.2 g of Jeffamine Di-2000 was injected and maintained at 110'C for 3 hours. When the final epoxy equivalent is 50,000 or more, 46.1 g of 2-butoxyethanol are added thereto, diluted, and cooled to 75 ° C. After neutralizing by adding 33.9 g of lactic acid, 1566.1 g of deionized water was gradually added to prepare an aqueous dispersion having a solid content of 25%.

Example 2

The hydroxyl containing polyepoxide-polyoxyalkylene amine compound useful in the present invention was prepared as follows in the composition of Table 2.

Reactant Parts by weight (g) 2-butoxyethanol 288.3 N8010 ¹ 298.7 Diethanolamine 22.9 Jeffamine D-2000N ² 328.4 2-butoxyethanol 61.7 Lactic acid 32.2 Deionized water 1567.8

1 is an epoxy resin having an epoxy equivalent of 480 obtained by reacting bisphenol-A and epichlorohydrin available from Koryo Chemical.

2 is a polyoxyalkylene diamine having a molecular weight of 2,000 available from Huntman, USA.

288.3 g of 2-butoxyethanol is injected into a reaction vessel provided with a stirrer, a thermometer, and a condenser, and the temperature is increased to 85 ° C. Insert 298.7 g of N8010 to dissolve completely, then cool to 45 ° C. When the proper temperature is reached, 22.9 g of diethanolamine is added thereto and maintained at 48 ° C. for 4 hours. At this time, when the epoxy equivalent was measured and reached about 1,500, 328.4 g of Jeffamine Di-2000 was injected and maintained at 110'C for 3 hours. When the final epoxy equivalent is 50,000 or more, 61.7 g of 2-butoxyethanol are added thereto, diluted and cooled to 75 ° C. After neutralizing by adding 32.2 g of lactic acid, 1567.8 g of deionized water was gradually added to prepare an aqueous dispersion having a solid content of 25%.

Example 3

A hydroxyl containing polyepoxide-polyoxyalkylene amine compound useful in the present invention was prepared as follows in the composition of Table 3.

Reactant Parts by weight (g) 2-butoxyethanol 299.6 N8010 ¹ 317.8 N-methylethanolamine 24.8 Jeffamine D-2000N ² 307.4 2-butoxyethanol 50.4 Lactic acid 24.0 Deionized water 1576.0

1 is an epoxy resin having an epoxy equivalent of 480 obtained by reacting bisphenol-A and epichlorohydrin available from Koryo Chemical.

2 is a polyoxyalkylene diamine having a molecular weight of 2,000 available from Huntman, USA.

299.6 g of 2-butoxyethanol was introduced into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, and the temperature was increased to 85 ° C. 317.8 g of N8010 is injected to dissolve completely and then cooled to 45 ° C. When the appropriate temperature is reached, 24.8 g of N-methylethanolamine is added thereto, and the reaction is maintained at 45 ° C. for 4 hours. At this time, when the epoxy equivalent was measured and reached about 1,500, 307.4 g of Jeffamine Di-2000 was injected and maintained at 110'C for 3 hours. When the final epoxy equivalent is 50,000 or more, 50.4 g of 2-butoxyethanol is added thereto, diluted, and cooled to 75 ° C. After neutralization by adding 24.0 g of lactic acid, 1576.0 g of deionized water is gradually added to prepare an aqueous dispersion having a solid content of 25%.

Example 4

A hydroxyl containing polyepoxide-polyoxyalkylene amine compound useful in the present invention was prepared as follows in the composition of Table 4.

Reactant Parts by weight (g) 2-butoxyethanol 291.0 N8010 ¹ 298.7 N-methylethanolamine 16.4 Jeffamine D-2000N ² 334.9 2-butoxyethanol 59.0 Lactic acid 22.6 Deionized water 1577.4

1 is an epoxy resin having an epoxy equivalent of 480 obtained by reacting bisphenol-A and epichlorohydrin available from Koryo Chemical.

2 is a polyoxyalkylenediamine having a molecular weight of 2,000 available from Huntman, USA.

291.0 g of 2-butoxyethanol was introduced into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, and the temperature was increased to 85 ° C. Insert 298.7 g of N8010 to dissolve completely and cool to 45 ° C. When the appropriate temperature is reached, 16.4 g of N-methylethanolamine is added thereto, and the reaction is maintained at 45 ° C. for 4 hours. At this time, when the epoxy equivalent was measured and reached about 1,500, 334.9 g of Jeffamine Di-2000 was injected and maintained at 110'C for 3 hours. When the final epoxy equivalent is 50,000 or more, 59.0 g of 2-butoxy ethanol are added and diluted and cooled to 75 ° C. Neutralize by adding 22.6 g of lactic acid, and then slowly add 1577.4 g of deionized water to prepare an aqueous dispersion having a solid content of 25%.

Comparative Example 1

As a comparative example, a polyepoxide-polyoxyalkylene amine compound having no polyalkanol monoamine modified was prepared as follows in the composition of Table 5.

Reactant Parts by weight (g) Jeffamine D-2000N ¹ 630 2-butoxyethanol 612 N8010 ² 262 Lactic acid 42.3 Deionized water 2021.7

1 is a polyoxyalkylene diamine having a molecular weight of 2,000 available from Huntman, USA.

2 is an epoxy equivalent of 480 epoxy resins reacted with bisphenol-A and epichlorohydrin, which is available from Korea Chemical.

630 g of Jeffamine Di-2000 and 612 g of 2-butoxyethanolamine are charged into a reaction vessel equipped with a stirrer, a thermometer, and a condenser and heated to 90 ° C. 262 g of N8010 is slowly injected and maintained at 110 ° C. for 3 hours. After checking the epoxy equivalent to 50,000 or more, and cooled to 75 ℃. After neutralizing with 42.3 g of lactic acid, 2021.7 g of deionized water was slowly added to prepare an aqueous dispersion of about 25% of a solid content.

Cationic Electrodeposition Coating Composition

The following cationic electrodeposition coating composition consists of the polyepoxide-polyoxyalkylene amine water-dispersion resin containing the hydroxyl group of the present invention, cationic resin, pigment paste and other additives.

Preparation Example 1

Preparation of the main resin, which is one of the components of the cationic electrodeposition paint, was carried out by reacting as follows in the composition shown in Table 6.

ingredient Parts by weight EPON 828 462.0 Bisphenol A 104.0 1,6-hexanediol 33.0 Anchor Amine 1040 ¹ 2.0 2-butoxyethanol 64.0 N-methylethanol amine 52.6 Hardener ² 453.8 Lactic acid 22.3 Deionized water 2173.0

1 is a fluorine-based catalyst commercially available from Air Products.

2 is a polyurethane curing agent wherein a toluene diisocyanate reactant half-blocked by 2-butoxyethanol and trimethylolpropane are formed in a 3: 1 molar ratio.

EPON 828, Bisphenol A, Anchoramine 1040 are heated at 180 ° C. until an epoxy equivalent of 950 is achieved. After cooling the reaction mixture to 80 ° C., 2-butoxyethanol and N-methyl ethanol amine are added. The reaction mixture is heated to 120 ° C. and maintained for 2 hours. When the epoxy equivalent is 30,000 or more, lactic acid is added to neutralize. After holding for 1 hour, the curing agent is added and stirred for 30 minutes. After completion of the reaction, deionized water was slowly added dropwise while stirring at high speed. The particle size of the prepared water-dispersed resin was 186 nm, and the solid content of the water dispersion was 39%.

Preparation Example 2

Preparation of Quaternization Agent

The pigment paste of the present invention is prepared from a pigment dispersion vehicle and a catalyst paste, and a quaternizing agent for preparing a pigment dispersion vehicle is prepared as follows in the composition of Table 7.

Quaternization ingredient Parts by weight (g) 2-ethylhexanol 1/2 blocked toluene diisocyanate 334.4 Dimethylethanolamine 95.8 Acetic acid 66 2-butoxyethanol 60.7

95.8 g of dimethylethanol amine is charged into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, and 334.4 g of 2-ethylhexanol 1/2 blocked toluene diisocyanate is added at room temperature. The reaction mixture is exothermic and kept at 80 ° C. for 1 hour. After acetic acid is added, 2-butoxyethanol is added.

Preparation Example 3

Preparation of Pigment Dispersion Vehicle

A pigment dispersion vehicle was prepared as follows in the composition of Table 8.

ingredient Parts by weight (g) N8030 900 Methyl Isobutyl Ketone 700 2-ethylhexanol 1/2 blocked toluene diisocyanate 524.8 2-butoxyethanol 1,450 Deionized water 60 Quaternization agent of Preparation Example 2 630

700 g of methyl isobutyl ketone was introduced into a reaction vessel provided with a stirrer, a thermometer, and a condenser, and the temperature was increased to 120 ° C., followed by gradually adding 900 g of N8030. To this was slowly added 2-ethylhexanol 1/2 blocked toluene diisocyanate for 1 hour. After holding the reaction mixture for 1 hour, 500 g of 2-butoxy ethanol were added and cooled to 80 ° C. Deionized water and a quaternizing agent are added and the reaction proceeds until the acid value is 1 or less. After completion of the reaction, 700 g of methyl isobutyl ketone was removed by vacuum distillation, and 950 g of 2-butoxyethanol was added to prepare a pigment dispersion vehicle having a solid content of 55%.

Preparation Example 4

Catalyst paste

Dibutyl tin oxide catalyst paste was prepared as follows in the composition of Table 9.

ingredient Parts by weight (g) Pigment Dispersion Vehicle of Preparation Example 3 174 Dibutyltin oxide 240 Deionized water 385.9

The components were dispersed in the mill up to Hegman gauge 8.

Preparation Example 5

Pigment paste

Pigment paste was prepared from a mixture of the components of Table 10 below.

ingredient Parts by weight (g) Titanium dioxide 733.6 Red silicate 42.9 Carbon black 21.5 Pigment Grinding Vehicle 294.3 Deionized water 505.6 Catalyst Paste of Preparation Example 4 113.6

The components are dispersed in a mill until a 7 with a Hegman gauge.

Preparation of Cationic Electrodeposition Coating Composition

The following examples are cationic electrodeposition coating compositions comprising the primary hydroxyl-containing polyepoxide-polyoxyalkylene amine resins of the present invention to improve the leveling of the coating surface without damaging top and adhesion. For comparison, a coating composition to which a polyepoxide-polyoxyalkylene amine resin having no modification of the polyalkanol monoamine of the prior art (US Pat. No. 4,432,850) was added and a coating composition not added thereto were prepared as follows. It was.

Comparative Example 2

As a standard example, a cationic electrodeposition coating composition containing no anti-crettling agent was prepared by mixing the components shown in Table 11 below.

ingredient Parts by weight Cationic electrodeposition resin of Preparation Example 1 1052.8 Paraplex WP-1 ¹ 25.3 Pigment paste of Production Example 5 273.4 Deionized water 1308.4

1 is a plasticizer available from Rohm and Haas.

After 40 minutes of ultrafiltration, the pH of the bath was 6.6 and the ratio of resin to pigment was 0.3: 1.

Comparative Example 3

As a comparative example, a cationic electrodeposition coating composition containing the unmodified polyepoxide-polyoxyalkylene amine resin prepared in Comparative Example 1 was prepared by mixing the components of Table 12 below.

ingredient Parts by weight Cationic electrodeposition resin of Preparation Example 1 1052.8 Resin of Comparative Example 1 142.7 Paraplex WP-1 ¹ 25.3 Pigment paste of Production Example 5 273.4 Deionized water 1308.4

1 is a plasticizer available from Rohm and Haas.

After 40 minutes of ultrafiltration, the pH of the bath was 6.6 and the ratio of resin to pigment was 0.3: 1.

Example 5

The cationic electrodeposition coating composition of the present invention was prepared by mixing the components of Table 13 below.

ingredient Parts by weight Cationic electrodeposition resin of Preparation Example 1 1052.8 The hydroxyl group-containing water dispersion resin prepared in Example 1 142.7 Paraplex WP-1 ¹ 25.3 Pigment paste of Production Example 5 273.4 Deionized water 1308.4

1 is a plasticizer available from Rohm and Haas.

The electrodeposition paint solution has a solid content of 20% and a ratio of pigment to binder of 0.3: 1.0.

Example 6

The cationic electrodeposition coating composition of the present invention was prepared by mixing the components of Table 14 below.

ingredient Parts by weight Cationic electrodeposition resin of Preparation Example 1 1052.8 The hydroxyl group-containing water dispersion resin of Example 2 142.7 Paraplex WP-1 ¹ 25.3 Pigment paste of Production Example 5 273.4 Deionized water 1308.4

1 is a plasticizer available from Rohm and Haas.

The electrodeposition paint solution has a solid content of 20% and a ratio of pigment to binder of 0.3: 1.0.

Example 7

The cationic electrodeposition coating composition of the present invention was prepared by mixing the components of Table 15 below.

ingredient Parts by weight Cationic electrodeposition resin of Preparation Example 1 1052.8 The hydroxyl group-containing water dispersion resin of Example 3 142.7 Paraplex WP-1 ¹ 25.3 Pigment paste of Production Example 5 273.4 Deionized water 1308.4

1 is a plasticizer available from Rohm and Haas.

The electrodeposition paint solution has a solid content of 20% and a ratio of pigment to binder of 0.3: 1.0.

Example 8

The cationic electrodeposition coating composition of the present invention was prepared by mixing the components of Table 16 below.

ingredient Parts by weight Cationic electrodeposition resin of Preparation Example 1 1052.8 The hydroxyl group-containing water dispersion resin of Example 4 142.7 Paraplex WP-1 ¹ 25.3 Pigment paste of Production Example 5 273.4 Deionized water 1308.4

1 is a plasticizer available from Rohm and Haas.

The electrodeposition paint solution has a solid content of 20% and a ratio of pigment to binder of 0.3: 1.0.

<Evaluation>

A cationic electrodeposition coating composition by electrodeposition coating was applied to the zinc phosphate treated steel sheet. When the electrodeposition paint was filtered through a 400 mesh wire mesh, no aggregates were collected. Electrodeposition coating was carried out using 270V for 3 minutes using the resulting coating composition on a cold rolled steel sheet surface-treated with a zinc phosphate base treatment agent (Parker Chemical Company, Parcolene®60). The coating was washed with water and baked in an oven at 168 ° C. for 30 minutes to obtain a film thickness of 25 microns. The electrodeposited specimens were coated with alkyd modified top coat (white and gray paint for top coat available from Korea Chemical).

The zinc phosphate-treated steel sheets contaminated with oil before electrodeposition were electrodeposited as described above, and the surface was visually measured to determine grades 0 to 10: grade 10 was very good and grade 0 was very poor.

Top adhesion was measured by Gravelometer from 0 to 10. The rating of (ASTM D-3170) 10 was very good and 0 was very poor.

Electrodeposition DOI ^* With white top coat DOI Gray Top Attachment Visual Evaluation of Electrodeposited Specimen Electrodeposition Thermal stability (60 ℃ × 2 weeks) Number of Creta Rings (9 x 20 cm per specimen) (0.5 mil) (1 mil) Comparative Example 2 87.8 2-3 95 3 One 0 Sedimentation ratio occurrence much Comparative Example 3 90.4 2 94 2-3 6 4 Precipitation occurrence 1 to 2 Example 5 90.1 7 92.1 6 5.5 3 Sedimentation ratio occurrence 0-1 Example 6 89.3 7 91 6 6 3.5 Sedimentation ratio occurrence 0-1 Example 7 89.8 6 94 5 6.5 4 Sedimentation ratio occurrence 0-1 Example 8 89.2 6 91 5 6 2 Sedimentation ratio occurrence 0-1

* DOI (Distinct Of Image to show image sharpness (measurement instrument: PGD Meter).

As can be seen from the above results, it can be seen that the electrodeposition coating composition to which the hydroxyl group-containing polyepoxide-polyoxyalkylene amine water-dispersible resin of the present invention is added has improved adhesion to the top coat upon coating.

As described above, the cationic electrodeposition coating composition including the polyepoxide-polyoxyalkylene amine water-dispersion resin containing the hydroxyl group of the present invention is excellent in adhesion to the top when coating, and the cratering and pinhole It is resistant to and has thermal stability, which is very useful for industry.

Claims (9)

In the presence or absence of a solvent, 1 equivalent of a polyepoxide-polyalkanol monoamine derivative represented by the following general formula (1), a polyoxyalkylene diamine represented by the following general formula (2) having a molecular weight of 150 to 3500, and / or the following general formula (3) A polyepoxide-polyoxyalkylene amine water-dispersion resin containing a hydroxyl group produced by reacting 1.05 to 3.0 equivalents of a polyoxyalkylene monoamine represented by the reaction at 50 to 150 ° C. Formula 1 Here, R ₁ and R ₂ may be the same or different from each other, at least one of R ₁ and R ₂ is an alkyl radical having 1 to 4 carbon atoms containing a hydroxyl group, R ₃ is 21 to carbon atoms containing an ether group 57 alicyclic or aromatic hydrocarbon radical. Formula 2 Here, R may be the same or different from each other, is selected from the group consisting of hydrogen or alkyl radicals of 1 to 6 carbon atoms, n is an integer of 1 to 50. Formula 3 Here, R may be the same or different from each other, is selected from the group consisting of hydrogen or alkyl radicals of 1 to 6 carbon atoms, n is an integer of 1 to 50. The polyepoxide-polyalkanol monoamine derivative according to claim 1, wherein the polyepoxide-polyalkanol monoamine derivative contains 30 to 0.5 equivalents of polyepoxide and 0.2 to 0.5 equivalents of polyalkanol monoamine represented by the following formula (4) in the presence or absence of a solvent. Dispersed resin, characterized in that prepared by reacting at 80 ℃. Formula 4 Here, R ₁ and R ₂ may be the same or different from each other, at least one of R ₁ and R ₂ is an alkyl radical having 1 to 4 carbon atoms containing a hydroxyl group. The water-dispersible resin according to claim 1 or 2, wherein the polyepoxide-polyalkanol monoamine derivative has 0.5 to 1 epoxy group and at least one hydroxyl group per molecule. The resin according to claim 1 or 2, wherein the solvent is selected from the group consisting of hydrocarbons, ethers, alcohols and ether-alcohols. The water-dispersible resin according to claim 1 or 2, wherein the polyalkanol monoamine is a secondary amine containing at least one hydroxyl group per molecule. The water-dispersible resin according to claim 1, wherein the polyepoxide is a polyglycidyl ether of a cyclic polyol. The water-dispersible resin according to claim 6, wherein the polyglycidyl ether of the cyclic polyol is bisphenol-A or hydrogenated bisphenol-A polyglycidyl ether having a molecular weight of 340 to 2000. The water-dispersible resin of claim 1, wherein the water-dispersible resin has a cationic group at least partially neutralized by acid. 2 to 5% by weight of a polyepoxide-polyoxyalkyleneamine water-dispersible resin containing a hydroxyl group according to any one of claims 1 to 8, 32 to 38% by weight of a cationic electrodepositable cationic resin, plasticizer A cationic electrodeposition coating composition comprising 1-2 wt%, deionized water 50-45 wt% and the rest of the other components.