KR20000046300A - Cationic electro-deposition paint composition containing alkyl glycidyl ether- or ester-amine coating layer forming additive - Google Patents

Abstract

PURPOSE: A cationic electro-deposition paint composition comprising a coating layer forming additive which has a limited water solubility and good coating layer retention effect and do not adversely affect the break voltage and anti-corrosion property of the paint is provided. CONSTITUTION: A cationic electro-deposition paint composition according to the present invention comprises: a) 0.05 to 20 wt% of alkyl glycidyl ether- or ester-amine coating layer forming additive characterized in that the ether- or ester-amine comprises the reaction product of primary or secondary amine and alkyl glycidyl ether or ester in the equivalent ratio of 1:1 or 1:2 and has at least 1 of hydroxy group and one or more alkyl group having at least 3 of carbon atoms based on the solid content of cationic electro-deposition resin water dispersion; and b) 2 to 60 wt% of cation electro-deposition resin composition containing 80 to 99.95 wt% of cationic electro-deposition resin comprising a curing agent.

Description

Cationic electrodeposition paint composition containing alkyl glycidyl ether or ester-amine coating film additive

The present invention relates to an electrodeposition coating composition containing a coating film forming additive, and more particularly to a cationic electrodeposition coating composition capable of obtaining a high coating film thickness.

Cationic electrodeposition introduces quaternary ammonium salts or sulfonium salts that can be positively charged into the resin, and they move to the cathode in the bath solution where the electric field is applied.At the same time, positive charges are generated by hydroxy anions generated by electrolysis of water. Precipitating resins are precipitated as they are reduced again, and they are coated on the negative electrode, that is, the subject.

Cationic electrodeposition coating method has the advantage of obtaining a uniform coating film thickness, there is a limit to secure a thick coating film. This disadvantage can be overcome by using a large amount of organic solvents such as glycol monoalkyl ethers and alcohols. However, these organic solvents are often undesirable because they evaporate from large open tanks and the effect on their concentration and film structure changes.

To overcome this, Korean Patent Publication No. 92-1391 describes a method of incorporating nonvolatile non-reactive components into an electrodeposition bath. However, most of these non-volatile non-reactive components should be used at high concentrations (4 to 20% by weight), which lowers the breakdown voltage of the coating film, which is undesirable. In addition, the hydrophilic functional groups in the nonvolatile non-reactive component promote the water content of the coating film formed by the electrodeposition coating, which adversely affects the process of washing with non-ionized water after the electrodeposition coating.

In addition, US Pat. No. 5,074,978 discloses that, for low molecular weight polyester adducts terminated with hydroxy groups as coating film forming agents, these hydroxy group terminated polyester adducts act as coating film forming agents and also have corrosion resistance. . However, these polyester adducts, when present in an aqueous medium, have the potential to hydrolyse over time and lose their effect as paint film formers.

An ideal coating film-forming additive not only improves the appearance but also exists in a small amount in the electrodeposition bath, and thus does not adversely affect properties such as breakdown voltage and corrosion resistance. In addition, the solubility in water should be limited so that it is non-volatile and does not deposit in the bath as electrodeposition proceeds, and the film-forming effect must be maintained over time. More preferably, it is necessary to improve the cohesion of the coating film generated during electrodeposition coating to show excellent results in the process of washing with non-ionized water after electrodeposition.

Accordingly, the inventors have invented through extensive research a cationic electrodeposition coating composition containing a film-forming additive that satisfies the ideal conditions listed above, and the present invention has been completed based on this.

Accordingly, it is an object of the present invention to provide a cationic electrodeposition coating composition comprising a coating film-forming additive that does not adversely affect properties such as breakdown voltage and corrosion resistance of a paint and is limited in solubility in water and has an excellent effect of maintaining film formation. have.

Cationic electrodeposition coating composition of the present invention for achieving the above object is made by reacting primary or secondary amines with alkyl glycidyl ethers or esters in an equivalent ratio of 1: 1 or 1: 2, respectively, and at least one per molecule An alkyl glycidyl ether or ester-amine coating film-forming additive having at least one or more hydroxy groups and at least one alkyl group having 3 or more carbon atoms is 0.05 to 20% by weight, preferably 0.1 to 10%, based on the total solids content of the cationic electrodeposition resin water dispersion. It consists of 2 to 60 weight% of cationic electrodeposition resin water dispersion compositions containing 80 to 99.95 weight% of cationic electrodeposition resin containing a weight% and a hardening | curing agent, and a pigment paste water.

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

This invention relates to the electrodeposition coating composition containing the coating film forming agent which forms a high coating film thickness.

The film forming agent of the present invention is obtained by reacting a primary or secondary amine with an alkyl glycidyl ether or ester in an equivalent ratio of 1: 1 or 1: 2, and at least one hydroxyl group and at least 3 carbon atoms, preferably Preferably an alkyl glycidyl ether or ester-amine compound having at least one or more alkyl groups of 4 to 12 carbon atoms, which is nonvolatile, has a limited solubility in water and does not hydrolyze even under aqueous media. In addition, the alkyl group present in the structure is characterized by increasing the cohesive force of the coating film to facilitate washing with non-ionized water after electrodeposition coating.

Examples of the primary or secondary amines used in the film forming additive of the present invention include aminoethoxyethanol amine, dimethyl amine, diethyl amine, N-methylethanol amine, diethanol amine, dicocoamine and the like.

In addition, examples of the alkyl glycidyl ether or ester used in the film forming additives include butyl glycidyl ether, 2-ethylhexyl glycidyl ether, glycidyl butyrate, Kadura E-10 (from Shell Chemical Company). Commercially available alkyl glycidyl ester compounds having a molecular weight of 250). When the amount of the primary amine and the alkyl glycidyl ether or ester used in the coating film forming additive is outside the range of 1: 2 (equivalent ratio), the unreacted amine and the unreacted alkyl glycidyl ether or ester and the cationic electrodeposition resin There is a risk of side reactions when forming water dispersion. In addition, in the case of secondary amines, the equivalent ratio of 1: 1 may cause side reactions for the same reason as described above.

The alkyl glycidyl ether or ester-amine compound, which is a coating film forming additive of the present invention, is injected with a primary or secondary amine into the reactor, and slowly reacted with an alkyl glycidyl ether or ester dropwise at 70 to 90 ° C. After maintaining for 3 hours at 90 ℃ is prepared by cooling to room temperature.

The alkyl glycidyl ether or ester-amine compounds of the present invention prepared in this way have a limited solubility in water. That is, when measured at 25 degreeC, it has the solubility of 0.01-30, Preferably 0.05-10 weight part with respect to 100 weight part of water. In addition, the alkyl glycidyl ether or ester-amine compound of the present invention has a boiling point of at least 200 ° C., preferably 250 ° C. or more under 1 atmosphere.

On the other hand, according to the present invention, there is provided a cationic electrodeposition coating composition comprising a resin dispersed in an aqueous medium. The water-dispersible resin includes the alkyl glycidyl ether or ester-amine compound on a solid content basis (including at least one hydroxyl group and at least one alkyl group having 3 or more carbon atoms, preferably 4 to 12 carbon atoms per molecule). 0.05 to 20% by weight, preferably 0.1 to 10% by weight and 80 to 99.95% by weight of a cationic electrodepositable resin containing a curing agent.

The cationic electrodepositable resin included in the cationic electrodepositable resin water dispersion used in the present invention is the main film forming resin in the electrodeposition coating composition. Examples of such film forming resins are amines such as acid solubilization products of polyepoxides with primary or secondary amines, as described in US Pat. Nos. 3,663,389, 3,984,299, 3,947,338 and 3,947,339. Salt group-containing resins. The polyepoxides used in the preparation of these polyepoxide-amine reaction products are polymeric materials containing at least two, preferably two epoxy groups per molecule. Such polyepoxides are well known in US Pat. Nos. 2,467,171, 2,615,007, 2,716,123 and 3,053,885. Examples of preferred polyepoxides are polyglycidyl ethers of polyphenols or polyglycidyl ethers of aromatic polyols such as bisphenol A. Such polyepoxides can be prepared by ether reaction of an epihalohydrin or diepihalohydrin such as epichlorohydrin or dichlorohydrin with an aromatic polyol in the presence of alkali. Examples of another polyepoxide may be derived from novolak resins or polyphenol resins.

On the other hand, the increase in molecular weight of polyglycidyl ethers of polyhydric materials is possible by the reaction of polyglycidyl ethers of aromatic diols with polyols which can react with epoxide groups. Examples of applicable polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, bisphenol-A and the like.

The primary and secondary amines reacting with the polyepoxide are preferably ketimines. It is mentioned in Korean Patent No. 94-9035 and already disclosed in US Patent No. 4,104,147. This specification is incorporated herein by reference. Ketimine groups are hydrolyzed when dispersing the polyepoxide-amine reaction product to release primary amine groups. The ketamine derivative may be a specific polyamine having at least one secondary amine group and capable of reacting with an epoxy group containing a primary amine group. Preferred polyamines are alkylene polyamines and substituted alkylene polyamines. Typical amines are diethylenetriamine, triethylenetetraamine and the like and the corresponding propylene, butylene and higher alkylene amines. Primary amine groups of the polyamine compound are converted to ketimine groups by reaction with ketones. Examples of preferred ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone and the like. Particularly preferred ketones are methyl ethyl ketone and methyl isobutyl ketone.

Secondary monoamines may be used in addition to the polyamine derivatives mentioned above. Examples of secondary monoamines include dimethyl amine, diethyl amine, N-methylethanol amine, diethanol amine and dicoco amine. Quaternary ammonium salts may also be used, which are obtained by reacting the aforementioned organic and inorganic acids with tertiary amines such as dimethylethanol amine.

The reaction of the polyepoxide with primary, secondary amine or quaternary ammonium salts and mixtures thereof occurs when the amine is added to the polyepoxide. The reaction may be exothermic and may require a cooling process. In order to prevent the gelation reaction during the reaction, the amine is preferably introduced at a time, and the epoxide functional group is used in excess of the amine. The reaction is usually carried out at 50 to 150 占 폚, preferably at 70 to 130 占 폚 for about 1 to 4 hours. The end point of the reaction is determined by measuring the content of epoxide functional groups in the usual manner.

The aqueous product of the polyepoxide-amine reaction product is prepared by neutralizing the reaction product with an acid and then introducing non-ionized water at 30 to 120 캜, preferably 50 to 90 캜.

The resin dispersion may contain a suitable organic solvent as a flocculating solvent. Preferred examples of these flocculating solvents include isopropanol, butanol, 2-ethylhexanol, isophorone, 2-butoxy ethanol, butyl carbitol, hexyl carbitol, ethylene and propylene glycol. The content of the flocculant solvent is preferably about 0.1 to 10% by weight based on the total weight of the resin dispersion.

The amount of alkyl glycidyl ether or ester-amine reactant used in the present invention is 0.05 to 20% by weight, preferably 0.1 to 10% by weight. If the amount is less than 0.05% by weight, there is a problem that a desired coating film thickness cannot be obtained. If the amount is more than 20% by weight, a problem of forming an excessive coating film thickness occurs.

The aqueous product prepared by the above method may include a pigment paste or various additives as necessary. For example, the pigment paste may not only have pigments having a color such as cadmium yellow, cadmium red, and chromium yellow, but also iron oxide, talc, and oxidation. Conventional types such as lead, strontium chromium, carbon black, coal powder, titanium dioxide and barium sulfate may be used. Additives include surfactants, wetting agents or curing catalysts. The above-mentioned additives are usually present in the dispersion in an amount of 0.01 to 3% by weight based on the resin solids.

The pigment content in the aqueous product is usually represented by a pigment to resin ratio, which is used within the range of 0.02 to 1: 1.

When the aqueous dispersion is used for electrodeposition, the aqueous dispersion is placed in contact with the electrically conductive cathode and the electrically conductive anode, with the surface to be painted as the cathode. After contact with the aqueous dispersion, when sufficient voltage is given between the electrodes, the adhesive film of the coating composition becomes the negative electrode. Electrodeposition conditions are generally similar to those for depositing other types of coatings, and the voltage used may vary. For example, it can be from as low as 1 volt to as high as thousands of volts, but typically from 50 to 500 volts. The current density is usually 0.05-0.5 amp / m ² , and the amount tends to decrease as the electrodeposition proceeds, since an insulating film is formed on the electrode surface to hinder the flow of current. 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. After electrodeposition coating, it is usually hardened by heat treatment at a temperature of about 90 to 260 ° 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.

Preparation Example 1

This preparation example relates to the preparation of an alkyl glycidyl ether or ester-amine compound which is a film forming additive of the present invention. The alkyl glycidyl ether or ester-amine compounds are prepared from the components shown in Table 1 below.

ingredient Parts by weight (g) N-methylethanol amine 75.1 Kadura-E10 ¹ 250.0

1. Alkyl glycidyl ester compound having a molecular weight of 250, commercially available from Shell Chemical co.

N-methylethanol amine is injected into the reactor and maintained at 70 ° C. Next, Kadura E10 is dripped gradually. The reaction is exothermic, with the temperature of the reactor not exceeding 90 ° C. When the dropping is complete, the reactor is heated to 90 ° C., maintained for 3 hours, titrated with an epoxy-amine equivalent in the reaction and terminated when the value reaches the theoretical value. The solids content of the intermediate product thus obtained is 100%.

Preparation Example 2

In the present preparation, an alkyl glycidyl ether or ester-amine compound was prepared in the same manner as in Preparation Example 1, except that diethanol amine was used and the amount of components. The alkyl glycidyl ether or ester-amine compounds are prepared from the components shown in Table 2 below.

ingredient Parts by weight (g) Diethanol amine 349.9 Kadura-E10 833.0

The compound was prepared as described in Preparation Example 1. The content of solids of the obtained intermediate is 100%.

Preparation Example 3

This preparation example was prepared in the same manner as in Preparation Example 1 except for the fact that aminoethoxyethanol amine, which is a primary amine, was used as the amine compound.

ingredient Parts by weight (g) Aminoethoxyethanol amine 210.2 Kadura-E10 250.0

The compound was prepared as described in Preparation Example 1. The content of solids of the obtained intermediate is 100%.

Preparation Example 4

This preparation was prepared with the components shown in Table 4 below as another example of an alkyl glycidyl ether or ester-amine compound.

ingredient Parts by weight (g) N-methylethanol amine 75.1 Glycidyl butyrate 144.2

N-methylethanol amine is injected into the reactor and maintained at 70 ° C. Then, glycidyl butyrate is slowly added dropwise. The reaction is exothermic, with the temperature of the reactor not exceeding 90 ° C. When the dropping is complete, the reactor is heated to 90 ° C., maintained for 3 hours, titrated with an epoxy-amine equivalent in the reaction and terminated when the value reaches the theoretical value. The solids content of the intermediate product thus obtained is 100%.

Preparation Example 5

This preparation was prepared in the same manner as in Preparation Example 4, except that butylglycidyl ether was used as the glycidyl ether compound and the amount of ingredients.

ingredient Parts by weight (g) N-methylethanol amine 75.1 Butylglycidyl ether 130.2

The compound was prepared as described in Preparation Example 4 above. The content of solids of the obtained intermediate is 100%.

Preparation Example 6

This manufacture example shows the manufacturing method of the cation resin which is a component of a cationic electrodeposition paint.

ingredient Parts by weight (g) N8010 ¹ 99.8 N8020 ² 15.0 Placel CL205 ³ 27.0 Xylene 100.0 Benzyldimethyl amine 0.6 Dowanol PPh ⁴ 11.0 Diketamine ⁵ 7.9 N-methylethanol amine 6.8

1.Product of Korea Chemical Co., Ltd., polyepoxide, molecular weight 960

2. Product of Korea Chemicals Co., Ltd., polyepoxide, molecular weight 1300

3. Products of Daicel, polycarbonate polyols, molecular weight 500

4. Dow's products, aromatic diluents

5. 73% solution of Air Products, diethylenetriamine dissolved in methyl isobutyl ketone as diketamine, blocked by methyl isobutyl ketone

In a 1 L reaction vessel equipped with a stirrer, a thermometer, a cooler, and a H-type separator, the polyepoxides N8010, N8020 and polycarbonate polyols and xylene in the amounts shown in Table 6 above were inserted and heated to 210 ° C. While holding at this temperature for about ten minutes, about 70 g of xylene is distilled out by the H-type separator, after being held for 30 minutes, cooled to 150 ° C., benzyldimethyl amine catalyst is added, and then heated to 180 ° C. for about 4 hours. React to degree. When the theoretical epoxy equivalent was reached, the mixture was cooled to 80 ° C. again, a dilution solvent, diketamine, and N-methyl ethanol amine were added thereto, followed by further reaction at 120 ° C. for about 2 hours. Once the theoretical epoxy equivalent and amine number have been reached, cool down to 80 ° C. and terminate the reaction.

Preparation Example 7

This preparation example is prepared with the composition shown in Table 7 below as a method for producing a curing agent used in the preparation of a polyepoxy-amine aqueous dispersion.

Reactant Parts by weight Toluene diisocyanate ¹ 320.0 2-butoxy ethanol 260.5 Dibutyltin dilaurate 3.2 Methyl isobutyl ketone 114.6 1,2,3-trimethylol propane 65.7

1.2,4-toluene diisocyanate / 2,6-toluene diisocyanate = 8/2

Toluene diisocyanate, dibutyl tin dilaurate and methyl isobutyl ketone in the amounts shown in Table 7 above were introduced into a 1 L reaction vessel equipped with a stirrer, a thermometer, and a cooler, and heated to 80 ° C., followed by dropwise 2-butoxy ethanol. do. After holding for 2 hours at this temperature, the NCO content is titrated and when this value reaches 30%, 1,2,3-trimethylol propane is added. After reacting for about 2 hours, the NCO content is again titrated and the reaction is terminated when this value reaches zero.

Preparation Example 8

This preparation example shows a method for producing a dispersion resin for producing a pigment paste as a component of a cationic electrodeposition paint, and is prepared by the mixture shown in Table 8 below.

Reactant Parts by weight Epicoat828 ¹ 171.7 Bisphenol-A 69.5 Triton X-100 ² 28.2 Xylene 100.0 Anchor 1040 ³ 1.0 N-methyl-2-pyrrolidone 10.0 Methoxy-2-propanol 100.0 KT-24 ⁴ 95.0 Acetic acid 20.0

1. Epoxy Resin of Shell Chemicals

2. Nonionic Emulsifiers of Alkyl Allyl Polyether Alcohols

3. Products of Air Products, trifluoroamine catalyst

4. A 73% solution of Air Products, diethylenetriamine, dissolved in methylisobutylketone as diketamine, blocked by methylisobutyl ketone.

Epon 828, Triton X-100 and xylene are placed in a reaction vessel equipped with a stirrer, a thermometer, a cooler and a H separator, and heated to 210 ° C. While held at 210 ° C. for 30 minutes, about 70 g of xylene are distilled off with an H type separator. After cooling to 160 ° C., an N-methyl-2-pyrrolidone solution containing bisphenol-A and anchor 1040 as a catalyst was added thereto, and then heated to 180 ° C. for 1 hour, and the epoxy equivalent was 1130. . Subsequently, after methoxy-2-propanol is gradually injected, it is cooled to 80 degreeC, KT-24 is inserted, and it raises and maintains at 120 degreeC again. After the maintenance reaction, the epoxy equivalent was confirmed to terminate the reaction. The synthesized epoxy amine resin is neutralized with acetic acid at 80 ° C. and deionized water is added. As a clear liquid, a water-dispersible resin having a solid content of 59.1% is prepared.

Preparation Example 9

This preparation example is for producing a pigment paste which is a constituent of electrodeposition paint, and is prepared by the mixture shown in Table 9 below.

Reactant Parts by weight Dispersion Resin of Preparation Example 8 40.0 Red silicate 17.4 Surfinol 104 ¹ 5.1 Carbon black 1.2 Titanium oxide 123.0 Dibutyl tin oxide 5.8 Deionized water 60.0

1. Emulsifier of Air Products

The ingredients are mixed together in the order indicated and stirred well, then dispersed up to Hegman No. 6 with a Dispermet SL-703 (BYK) disperser. The solid content of the pigment paste thus obtained is 66.3% by weight.

Comparative Production Example 1

This preparation is to prepare an electrodeposition resin that does not contain an alkyl glycidyl ether or ester-amine compound, and is prepared by the components shown in Table 10 below.

ingredient Parts by weight (g) Cationic Resin of Preparation Example 1 198.0 Curing agent of Production Example 7 92.0 Chopsan 7.4 Deionized water 335.2

The solvent is removed in vacuo at 100 ° C., followed by hydrolysis of the ketamine group by addition of acetic acid and a small amount of water. This is cooled to room temperature again, and the remaining deionized water is added to disperse the water, thereby preparing a water dispersion resin having a solid content of about 40%.

Preparation Example 10

This preparation is to prepare an electrodeposition resin containing an alkyl glycidyl ether or ester-amine compound prepared in Preparation Example 1, and is prepared by the components shown in Table 11 below.

ingredient Parts by weight (g) Cationic Resin of Preparation Example 6 198.0 Curing agent of Production Example 7 92.0 Compound of Preparation Example 1 1.6 Chopsan 7.4 Deionized water 335.2

After removing the solvent in vacuo at 100 ° C., the compound of Preparation Example 1 and lactic acid were added thereto, and a small amount of water was added to hydrolyze the ketimine group. This is cooled to room temperature again, and the remaining deionized water is added to disperse the water, thereby preparing a water dispersion resin having a solid content of about 40%.

Preparation Example 11

A compound of Preparation Example 1 was prepared in the same manner as in Preparation Example 10 except for using 0.8 g.

Preparation Example 12

A compound of Preparation Example 1 was prepared in the same manner as in Preparation Example 10 except for using 3.2 g.

Preparation Example 13

Preparation was carried out in the same manner as in Preparation Example 10, except that the compound prepared in Preparation Example 2 was used instead of the compound of Preparation Example 1.

Preparation Example 14

Preparation was carried out in the same manner as in Preparation Example 10, except that the compound prepared in Preparation Example 3 was used instead of the compound of Preparation Example 1.

Preparation Example 15

Preparation was carried out in the same manner as in Preparation Example 10, except that the compound prepared in Preparation Example 4 was used instead of the compound of Preparation Example 1.

Preparation Example 16

Preparation was carried out in the same manner as in Preparation Example 10, except that the compound prepared in Preparation Example 5 was used instead of the compound of Preparation Example 1.

Comparative Example 1

This comparative example is for producing an electrodeposition paint containing no alkyl glycidyl ether or ester-amine compound and is prepared by the mixture of Table 12 below.

ingredient Parts by weight (g) Cationic Resin of Comparative Production Example 1 320.0 Deionized water 542.0 Pigment paste of Preparation Example 4 96.0

Example 1

Preparation was carried out in the same manner as in Comparative Example 1, except that Preparation Example 10 was used instead of the Cationic Resin of Comparative Preparation Example 1.

Example 2

Preparation was carried out in the same manner as in Comparative Example 1, except that Preparation Example 11 was used instead of the cationic resin of Comparative Preparation Example 1.

Example 3

Preparation was carried out in the same manner as in Comparative Example 1, except that Preparation Example 12 was used instead of the Cationic Resin of Comparative Preparation Example 1.

Example 4

Preparation was carried out in the same manner as in Comparative Example 1, except that Preparation Example 13 was used instead of the Cationic Resin of Comparative Preparation Example 1.

Example 5

Preparation was carried out in the same manner as in Comparative Example 1, except that Preparation Example 14 was used instead of the Cationic Resin of Comparative Preparation Example 1.

Example 6

Preparation was carried out in the same manner as in Comparative Example 1 except that Preparation Example 15 was used instead of the Cationic Resin of Comparative Preparation Example 1.

Example 7

Preparation was carried out in the same manner as in Comparative Example 1, except that Preparation Example 16 was used instead of the Cationic Resin of Comparative Preparation Example 1.

The electrodeposition paint prepared above is subjected to electrodeposition coating for 2 minutes at a constant voltage of 240 volts on a cold-rolled steel sheet (9 mm X 20 mm) surface-treated with a zinc phosphate treatment agent. The resulting coating is washed with water and baked in an oven at 170 ° C. for 30 minutes to obtain a coating of constant thickness. The film thickness and breakdown voltage of the electrodeposition paint containing the alkyl glycidyl ether or the ester-amine compound as the film forming additive are shown in Table 13 below.

Corner Corrosion Degree of Comparative Example 1 and Examples 1 to 7 Example Coating Agent Content (Resin Solid Weight%) Coating thickness (μm) Breakdown voltage ¹ (volts) Electrodeposition film flush ² Comparative Example 1 0.0 20 340 Defective Example 1 0.8 26 330 Good Example 2 0.4 24 340 Good Example 3 1.6 30 310 Good Example 4 0.8 28 330 Good Example 5 0.8 29 320 Good Example 6 0.8 26 330 Good Example 7 0.8 24 310 Defective

1. Breakdown voltage is indirectly measured by resistance to the formation of pinholes in the coating during the electrodeposition process on the galvanized steel substrate. In this test, electrodeposition is carried out at the same electrodeposition time until small holes are produced at 10 volt intervals at a bath temperature of 28 ° C. The voltage at which a small hole begins to form is the breakdown voltage.

2. Flushability of electrodeposited coating film is indirectly measured by the presence or absence of bubble marks remaining on hardened coating film after hardening steel substrate taken out of electrodeposition bath after electrodeposition process on galvanized steel substrate for 30 minutes. In the test, the galvanized steel substrate is made into an L-shape, followed by an electrodeposition process, taken out of the electrodeposition bath and washed with non-ionized water. Subsequently, it is cured immediately in an oven without time interval and the number of bubble traces remaining on the L-shaped horizontal plane and the lower end is measured. In the case of curing in a high temperature oven immediately after washing with non-ionized water, the number of bubbles is determined depending on the amount of moisture contained in the formation of bubble marks due to the rapid evaporation of the moisture contained in the resulting electrodeposition film. If bubble marks remain on the upper and lower ends of the L-shaped steel substrate, flushing is poor.

As discussed above, the alkyl glycidyl ether or ester-amine compound, which is a film forming additive of the present invention, is nonvolatile, has a limited solubility in water, and does not hydrolyze even under an aqueous medium. In addition, due to the alkyl group present in the structure, the cohesion of the coating film is increased to facilitate washing with non-ionized water after electrodeposition coating, and when applied to electrodeposition paint, the coating film thickness can be increased without lowering the breakdown voltage. In addition, it has the advantage of increasing the water washing effect by non-ionized water after the electrodeposition process is very useful in industry.

Claims (7)

In the cationic electrodeposition coating composition, a primary or secondary amine and an alkyl glycidyl ether or ester are reacted in an equivalent ratio of 1: 1 or 1: 2, respectively, and include at least one hydroxy group and an alkyl group having 3 or more carbon atoms per molecule. Alkyl glycidyl ether or ester-amine coating film-forming additive having at least one or more, based on the solids content of the cationic electrodeposition resin water dispersion, 0.05 to 20% by weight, cationic electrodepositable resin containing a curing agent 80 to 99.95 A cationic electrodeposition coating composition comprising 2 to 60% by weight of a cationic electrodeposition resin composition comprising a weight%. The method of claim 1, wherein the primary or secondary amine is characterized in that one selected from the group consisting of aminoethoxyethanol amine, dimethyl amine, diethyl amine, N- methyl ethanol amine, diethanol amine and dico amine Cationic electrodeposition coating composition. The method of claim 1, wherein the alkyl glycidyl ether or ester is one selected from the group consisting of butyl glycidyl ether, 2-ethylhexyl glycidyl ether, glycidyl butyrate and Kadura E-10. Cationic electrodeposition coating composition. The cationic electrodeposition coating composition according to claim 1, wherein the coating film forming additive has at least one alkyl group having 4 to 12 carbon atoms. The cationic electrodeposition coating composition according to claim 1, wherein the cationic electrodepositable resin is prepared by chain-extending a polyepoxide with a polyol, reacting with a primary or secondary amine, and neutralizing with an acid. 6. The cationic electrodeposition coating composition according to claim 5, wherein the polyepoxide is one selected from the group consisting of polyglycidyl ethers of polyphenols and polyglycidyl ethers of aromatic polyols. The polyol of claim 5, wherein the polyol is one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol and bisphenol A Cationic electrodeposition coating composition characterized in that.