KR100576404B1 - β-Hydroxyalkyl carbamate-modified pigment grinding vehicle and said vehicle-containing cationic electro-deposition paint composition - Google Patents

Abstract

The present invention relates to a resin for beta hydroxyalkyl carbamate-modified pigment dispersion and a cationic electrodeposition coating composition containing the same, and more particularly, to pigment dispersibility and storage containing a beta hydroxyalkyl carbamate group as a pigment dispersion stabilizing group. It relates to a process for producing a pigment dispersion resin having high stability and a cationic electrodeposition coating composition containing the resin for pigment dispersion.

The present invention further relates to pigment paste resins prepared according to the process and their use in cathodic depositable coating compositions. The product prepared according to the invention changes the composition of the pigments used, since the rheology proceeds easily, forms a film without bonds in both deposition and crosslinking reactions, and does not adversely affect the properties of the crosslinked film. However, it is possible to produce pigment pastes that meet a variety of practical requirements, with stability to meet practical requirements in both concentrated and dilute forms.

Description

Β-Hydroxyalkyl carbamate-modified pigment grinding vehicle and said vehicle-containing cationic electro-deposition paint composition}

The present invention relates to a resin for beta hydroxyalkyl carbamate-modified pigment dispersion and a cationic electrodeposition coating composition containing the same, and more particularly, to pigment dispersibility and storage containing a beta hydroxyalkyl carbamate group as a pigment dispersion stabilizing group. It relates to a process for producing a pigment dispersion resin having high stability and a cationic electrodeposition coating composition containing the resin for pigment dispersion.

Electrodeposition coating refers to a technology in which a polymer having a charge moves to an electrode of opposite charge under a direct current action, and a change in pH caused by electrolysis of water at the electrode causes polymer precipitation to form a non-conductive coating film. The importance of these electrodeposition methods is increasing because they provide higher adhesion efficiency, significant corrosion resistance, and low environmental pollution compared to non-electrophoretic means.

Initially, electrodeposition was carried out with the anode to be painted. This is known as anion electrodeposition. However, the cationic electrodeposition method which improved the rust prevention property of the said anion electrodeposition was introduced in 1972. Since then, cationic electrodeposition has steadily gained popularity and has become the primary electrodeposition method today. More than 80% of all cars produced worldwide are undercoat by cation electrodeposition. In the meantime, in cationic electrodeposition, in order to satisfy the various functions required, resins for pigment dispersion have been developed in electrodeposition paints, and the two-component forming of paints has become a practical use.

Pigment dispersion resins used for cationic electrodeposition should not only ensure the long-term storage stability of the paint, but also be free of this phenomenon and appearance defects of electrodeposition behavior. The content regarding the resin for dispersion used for cation electrodeposition is known. The key technique of these compositions is how to introduce certain pigment dispersion stabilizing groups (ie primary or secondary amine salts and onium salts) into the epoxy resin. As a representative example, resins containing quaternary ammonium salts are known to have excellent dispersibility in pigments containing lead. As illustrated in US Pat. Nos. 4,007,154 and 4,186,124, it is known to contain quaternary ammonium salts or sulfonium groups to stabilize pigment dispersion. However, the patent stabilizes the pigment dispersion by the onium salt, and the effect is excellent, but the salt group is not destroyed in the coating film after electrodeposition, and has a disadvantage in that the horizontal leveling is poor after curing.

On the other hand, resins containing primary, secondary and tertiary amine salts as dispersion resins are known, which smooth the electrodeposited coating film, but are not only difficult to obtain satisfactory pigment dispersion, but also are stable in the long term storage of the electrodeposition bath. This has the disadvantage of falling. That is, since the amine salts are salt groups containing protons, storage stability is poor due to proton exchange reaction during pigment dispersion and storage.

However, the introduction of suitable hydrophilic groups into these primary, secondary and tertiary amine salts can improve the pigment dispersion and storage stability of these resins. By introducing the hydrophilic group, since the steric stabilization effect is imparted to the resin for dispersion, pigment dispersion and storage stability can be improved. Therefore, in the production of resin for pigment dispersion, what hydrophilic group is introduced into the resin for dispersion is an issue. For example, an epoxy resin pigment paste resin containing an oxazolidine group described in the Federal Republic of Austria Patent Applications 365,214 and 380,264 is exemplified. The oxazolidine groups of the resin are hydrolyzed in the bath solution and converted to hydroxymethyl groups to provide hydrophilic groups. This type of resin has a problem of poor shelf life in the bath solution, but is known to be actually used because of good pigment dispersibility. Pigment dispersion resins containing imidazoline groups as resins containing another hydrophilic group are exemplified in US Pat. Nos. 4,710,561 and 5,128,393. The imidazoline group is hydrolyzed and has the advantage of improving pigment dispersibility by providing an amide group which is a hydrophilic group, but has a disadvantage in that an additional process for forming imidazoline is cumbersome.

Therefore, while satisfying both excellent pigment dispersion and storage stability at the same time, it is required to develop a resin for pigment dispersion that can be produced by a simple process.

In order to overcome the drawbacks of the conventional pigment dispersion resins, the present inventors have conducted extensive research, and have developed a resin for pigment dispersion that can be used in various electrodeposition paint compositions having excellent pigment dispersion property and storage stability. The invention has been completed based on this.

In the production of pigment dispersion resin, the pigment dispersion resin having a beta hydroxyalkyl carbamate represented by the following formula (1) as a hydrophilic group by a step omitted from the existing patent technology is excellent in pigment dispersion property, We found good physical properties.

[Formula 1]

Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different from each other and are hydrogen, methyl or ethyl groups.

Therefore, an object of the present invention is to provide a pigment dispersion resin containing beta hydroxyalkyl carbamate.

Another object of the present invention to provide a cationic electrodeposition coating composition containing a resin for pigment dispersion containing the beta hydroxyalkyl carbamate.

Beta-hydroxyalkyl carbamate-modified pigment dispersion resin of the present invention for achieving the above object is a polyepoxide derived from a mixture of a polyepoxide compound and a polyamine derivative or secondary amine having at least one active hydrogen Produced by neutralizing an amine group with 5 to 50 parts by weight of an organic acid with respect to 100 parts by weight of a resin obtained by reacting 60 to 98% by weight of an amine resin with 2 to 40% by weight of a cyclic carbonate represented by the following Chemical Formula 2 at 20 to 80 ° C. do.

[Formula 2]

Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different from each other and are hydrogen, methyl or ethyl groups.

The organic acid for achieving the above object is acetic acid, formic acid and lactic acid, and contains 0.20-1.50 milliequivalents of salt groups per 1 g of the resin solids obtained by neutralizing the amine groups.

The electrodeposition coating composition of the present invention for achieving the above another object is 80 to 95 parts by weight of the main resin used for electrodeposition comprising an isocyanate-blocked curing agent and melamine curing agent, the betahydroxy alkyl carbamate modified pigment dispersion according to claim 1 5 to 20 parts by weight of the resin, the pigment dispersed by the dispersion resin having a weight ratio of the pigment to the betahydroxy alkyl carbamate-modified pigment dispersion resin is 0.05 to 0.5 and optionally dibutyltin oxide 0.05 to catalyst 5 parts by weight.

Looking at the present invention in more detail as follows.

The present invention relates to polyglycidyl ether derivatives of polyhydric materials, i.e., polyepoxyamine derivatives derived from a mixture of a polyepoxide compound and a polyamine derivative having at least one or more active hydrogens or a monoamine, as essential elements. It relates to a pigment dispersion resin obtained by reacting a cyclic carbonate and a cationic electrodeposition coating composition containing these resins.

Glyglycidyl ethers of the polyhydric materials have 180-2000 epoxide equivalents per molecule, and preferably have two or more 1,2-epoxide groups. The content of polyepoxides is well known. For example, these polyepoxides are known from US Pat. Nos. 2,467,171, 2,615,007, 2,716,123, 3,053,855, 3,075,999, and the like. 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 epihalohydrin or diepihalohydrin such as epichlorohydrin or dichlorohydrin with an aromatic polyol in the presence of alkali. Another example of an epoxide can be derived from noblock resins or polyphenol resins. On the other hand, increasing the molecular weight of polyglycidyl ethers of polyhydric materials is possible by the reaction of polyglycidyl ethers of aromatic diols with polyols that can react with epoxide groups. Examples of applicable polyols are ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol and bisphenol-A and the like.

Polyepoxides in the present invention have a molecular weight of at least 350 or more, preferably between 100 and 3000.

The amine reacting with the polyepoxide means a polyamine having at least one amine group, preferably a ketimine derivative in which the primary amine is blocked by a ketone and has at least one secondary amine. .

The ketamine groups are mentioned in US Pat. No. 4,104,147, and as dispersed in water, the polyepoxide amine reactant is hydrolyzed to primary amine groups. Ketamine derivatives may be polyamines having substantially at least one secondary amine and primary amine groups and capable of reacting with 1,2-epoxide groups. Typical polyamines are diethylene triamine, triethylene tetraamine and the like, and the corresponding propylene, butylene and longer chain alkylene amines. Primary amine groups of the polyamine compound are converted to ketimine groups by reaction with ketones. In addition to polyamine derivatives, amines capable of reacting with polyepoxides can be used as mixtures of polyamine derivatives and secondary amines. Secondary amines include diethyl amine, N-methylethanolamine, dicocoamine, and the like.

The reaction of the amine with the polyepoxide occurs by the mixture of polyepoxide and amine. The reaction may be without solvent or optionally with solvent. The reaction is exothermic, sometimes requiring cooling to 50-160 ° C., generally requiring a temperature between 50-150 ° C.

In the above reaction, in order to facilitate the reaction with the cyclic carbonate, it is necessary to decompose the diketamine of the amine resin and convert it to a primary amine. Decomposition of diketamine can be induced by adding distilled water containing 1% of normal organic acid concentration and maintaining it at 50 to 100 ° C for 2 hours. Theoretically, this reaction means a 2-100% reaction on the basis of one equivalent of the number of moles of primary amine, and the resulting chemical structure is characterized by having the following functional groups.

Formula 1

Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different from each other, hydrogen, methyl or ethyl group.

Introduction of the betahydroxyalkyl carbamate (Formula 1) is possible by the reaction of the cyclic carbonate represented by the following formula (2) and the polyepoxide amine resin.

Formula 2

Wherein R ₁ , R ₂ , R ₃ and R ₄ are as described above.

The content of the cyclic carbonate participating in the reaction greatly affects the hydrophilicity of the resin for dispersion. If the content of the cyclic carbonate exceeds 40% by weight, it shows hydrophilicity, and the amine value of the resin is too low, which may cause lowering the long-term storage stability of the final paint. On the other hand, when the content of the betahydroxyalkyl carbamate group contained in the resin is less than 2% by weight, the wettability of the pigment is inferior. Therefore, the content of betahydroxyalkyl carbamate per resin solid content, that is, the content of cyclic carbonate participating in the reaction, is 2 to 40% by weight, preferably 5 to 25% by weight.

The beta hydroxyalkyl carbamate-modified pigment dispersion resin for application to electrodeposition is neutralized with organic acids such as acetic acid, lactic acid or formic acid and requires the introduction of cationic groups into the resin. In such cationic electrodeposition, the resin containing the cationic group is an essential element for the pigment to wet and adhere to the workpiece under dispersion stabilization and electrodeposition conditions. The equivalent number of salts per gram of resin to make a suitable pigment grinding developer is preferably 0.20 to 1.50 milliequivalents. If the equivalent number of the salt is less than 0.20 milliequivalents per gram of resin, it is not preferable because it has poor pigment wettability, and if it exceeds 1.50 milliequivalents, it is not preferable because the resin becomes too water soluble.

Toluene diisocyanate groups partially blocked by aliphatic monoalcohol may be introduced in order for the polyepoxide used in the present invention to have better pigment dispersion. Processes for preparing aliphatic monoalcohol modified epoxy resins are well known in US Pat. No. 4,007,154.

The pigment dispersion resin prepared according to the present invention has a rheology that easily proceeds, forms a defect-free film in both deposition and crosslinking reactions, and is excellent in appearance and practical even if the composition of the pigment used is changed. It is possible to produce pigment pastes that meet various requirements.

Pigment pastes of the present invention are prepared by grinding or dispersing the pigment into the cationic resin in a very well known manner. Pigment pastes are an essential component of the invention and contain betahydroxyalkyl carbamate-modified epoxide amine resins neutralized in organic salts and consist of one or more pigments. The paste may also contain any ingredients such as plasticizers, wetting agents, surfactants or defoamers. The composition ratio of the said betahydroxyalkyl carbamate modified epoxyamine resin and a pigment is 0.05 or more, Preferably it is 0.10-0.5. If the pigment composition ratio is less than 0.05, problems such as possessive occlusion rate and hardening insufficiency occur, and if it exceeds 0.5, problems of impact resistance and rough appearance of the coating film occur.

Grinding is generally carried out using bowl mills, sand mills, coulse dissolvers, continuous mills and the like until the pigments are reduced to the desired size, preferably until wet or ground by the grinding colorant. Generally, about 5 or more, and preferably about 7-8, are used as Hegman gauge. Grinding is carried out in an aqueous dispersion of the colorant. The amount of water present in the aqueous mill must be sufficient to produce a continuous aqueous phase. The aqueous mill generally contains about 40-80% solids. If the amount of water used is more than 80%, only the effective capacity of the grinding is reduced, and if less than 20%, it may cause the problem of gelation during dispersion.

In general, although the pigment paste is prepared in the presence of water, water is not absolutely critical, and in fact the pigment dispersant of the present invention can be used to prepare non-aqueous pigment pastes which can subsequently be dispersed in the water base composition. In the grinding step, the pigment-binder ratio is about 1-10: 1, preferably about 5-8: 1.

In some cases, a pigment composition and, if desired, various additives such as surfactants, wetting agents or catalysts may be included in the dispersion. The pigment composition is, for example, a common type including pigment pigments such as cadmium yellow, cadmium red and chromium yellow, as well as iron oxide, lead oxide, strontium chromium, carbon black, coal powder, titanium dioxide, talc and barium sulfate. Can be. The other additives mentioned above are usually added to the dispersion in an amount of about 0.01 to 3% by weight, based on the resin solids.

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-ethylhexanol, isophorone, 4-methoxy-pentanone, ethylene and propylene glycol and monoethyl, monobutyl and monohexyl ethers of ethylene glycol, and the like. The amount of flocculant is generally about 0.01 to 25% by weight based on the weight of the aqueous medium, preferably 5% by weight when used.

When the above-mentioned aqueous dispersion is used for electrodeposition, with the surface to be painted as a cathode, the aqueous dispersion is placed in contact with the electrically conductive cathode and the electrically conductive anode. 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. 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 between 0.5 and 5 amps / ft ² and tend to decrease during electrodeposition because insulating films are formed. The coating compositions of the present invention can be used on various 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 and Comparative Examples, but the scope of the present invention is not limited to the following Examples.

Comparative Production Example 1

To compare with the present invention, a resin in which the betahydroxyalkyl carbamate was not included in the polyepoxide amine resin was prepared as follows.

TABLE 1

¹ silver shell chemical epoxy resin

² is a product of Air Product, a trifluoroamine catalyst

³ is a 75% solution of air product, diethylenetriamine dissolved in methyl isobutyl ketone as diketamine blocked by methyl isobutyl ketone

In a reaction vessel equipped with a stirrer, a thermometer and a condenser, insert 320 g EPON 828, 116 g bisphenol-A, 1.6 g anchor 1040, 240 g methyl isobutyl ketone and 16 g N-methyl-2-pyrrolidone Heated to ° C. After holding for 2 hours, the mixture was cooled to 120 ° C. 197 g of half-blocked toluene diisocyanate was slowly injected for 1 hour and then maintained for 2 hours. 350 g of 2-butoxyethanol and 244 g of KT-22 were added at 120 DEG C and held for 2 hours. 100 g of pure water was slowly added and cooled to 80 ° C. 456 g of methyl isobutyl ketone was removed from the reaction mixture by vacuum distillation. 569 g of 2-butoxyethanol and 48.7 g of acetic acid were added to prepare a pigment dispersion resin having a solid content of 50%.

Preparation Example 1

A betahydroxyalkyl carbamate modified amine derivative to be reacted with a polyepoxide compound was prepared as follows.

TABLE 2

103.2 g of diethylenetriamine and 131 g of 2-butoxyethanol were inserted into a reaction vessel provided with a stirrer, a thermometer, and a condenser, and the temperature was raised to 80 ° C. 204 g of propylene carbonate was added slowly over 1 hour. After the holding reaction for 2 hours, the amine value is measured and equivalently measured by a conventional method, and maintained until it is reduced to a total of 2/3 equivalents. Thereafter, the reaction vessel was cooled to room temperature to obtain a reactant having a 70% solid content.

Preparation Example 2

Using the solid reaction product of Preparation Example 1, a pigment dispersion resin containing 6% by weight of a betahydroxyalkyl carbamate group was prepared as follows.

TABLE 3

¹ silver shell chemical epoxy resin

² is a product of Air Product, a trifluoroamine catalyst

³ is a 75% solution of air product, diethylenetriamine dissolved in methyl isobutyl ketone as diketamine blocked by methyl isobutyl ketone

Into a reaction vessel equipped with a stirrer, a thermometer and a condenser, 320 g of EPON 828, 116 g of bisphenol-A, 1.6 g of anchor 1040, 240 g of methyl isobutyl ketone, and 16 g of N-methyl-2-pyrrolidone were placed at 160 ° C. Heated to It was held for 2 hours and then cooled to 120 ° C. 197 g of semi-blocked toluene diisocyanate was slowly inserted for 1 hour and held for 2 hours. At 120 ° C., 350 g of 2-butoxyethanol, 122 g of KT-22 and 140 g of the reaction of Preparation Example 1 above were added and maintained for 2 hours. 100 g of pure water was slowly added and cooled to 90 ° C. 100 g of pure water and 1.5 g of formic acid were inserted at 90 DEG C, and 51.4 g of propylene carbonate was added slowly. After maintaining the reaction for 2 hours, 456 g of methyl isobutyl ketone was removed by vacuum distillation from the reaction mixture. 569 g of 2-butoxyethanol and 48.7 g of acetic acid were added to prepare a pigment dispersion resin having a solid content of 50%.

Preparation Example 3

Dispersion resin containing 12.5% by weight of betahydroxyalkyl carbamate group was prepared by a method similar to Preparation Example 2.

TABLE 4

¹ silver shell chemical epoxy resin

² is a product of Air Product, a trifluoroamine catalyst

³ is a 75% solution of air product, diethylenetriamine dissolved in methyl isobutyl ketone as diketamine blocked by methyl isobutyl ketone

Into a reaction vessel equipped with a stirrer, a thermometer and a condenser, 320 g of EPON 828, 116 g of bisphenol-A, 1.6 g of anchor 1040, 240 g of methyl isobutyl ketone, and 16 g of N-methyl-2-pyrrolidone were placed at 160 ° C. Heated to It was held for 2 hours and then cooled to 120 ° C. 197 g of semi-blocked toluene diisocyanate was slowly inserted for 1 hour and held for 2 hours. At 120 ° C., 350 g of 2-butoxyethanol, 122 g of KT-22 and 140 g of the reaction of Preparation Example 1 above were added and maintained for 2 hours. 100 g of pure water was slowly added and cooled to 90 ° C. 100 g of pure water and 1.5 g of formic acid were inserted at 90 DEG C, and 103.8 g of propylene carbonate was added slowly. After holding for 2 hours, 456 g of methyl isobutyl ketone was removed by vacuum distillation from the reaction mixture. 569 g of 2-butoxyethanol and 48.7 g of acetic acid were added to prepare a pigment dispersion resin having a solid content of 50%.

Preparation Example 4

Dispersion resins containing 18.7% by weight of betahydroxyalkyl carbamate groups were prepared in a similar manner to Preparation Example 2.

TABLE 5

¹ silver shell chemical epoxy resin

² is a product of Air Product, a trifluoroamine catalyst

³ is a 75% solution of air product, diethylenetriamine dissolved in methyl isobutyl ketone as diketamine blocked by methyl isobutyl ketone

Into a reaction vessel equipped with a stirrer, a thermometer and a condenser, 320 g of EPON 828, 116 g of bisphenol-A, 1.6 g of anchor 1040, 240 g of methyl isobutyl ketone, and 16 g of N-methyl-2-pyrrolidone were placed at 160 ° C. Heated to It was held for 2 hours and then cooled to 120 ° C. 197 g of semi-blocked toluene diisocyanate was slowly inserted for 1 hour and then held for 2 hours. At 120 ° C., 350 g of 2-butoxyethanol, 122 g of KT-22 and 140 g of the reaction of Preparation Example 1 above were added and maintained for 2 hours. 100 g of pure water was slowly added and cooled to 90 ° C. 100 g of pure water and 1.5 g of formic acid were inserted at 90 DEG C, and 155.8 g of propylene carbonate was added slowly. After maintaining the reaction for 2 hours, 456 g of methyl isobutyl ketone was removed from the reaction mixture by vacuum distillation. 569 g of 2-butoxyethanol and 48.7 g of acetic acid were added to prepare a pigment dispersion resin having a solid content of 50%.

Comparative Example 1

Titanium dioxide, carbon black, basic lead silicate and butyl tin oxide were dispersed in the pigment dispersion resin of Comparative Production Example 1.

TABLE 6

¹ Hexininol wetting agent of Air Product

The components were mixed in the order indicated and stirred well, then dispersed to Hegman No. 6 with a Dispermet SL-703 (BYK) disperser.

Example 1

A pigment paste was prepared in a similar manner to Comparative Example 1 except that Production Example 2 was used as the pigment dispersion resin.

Example 2

A pigment paste was prepared in a similar manner to Comparative Example 1 except that Production Example 3 was used as the pigment dispersion resin.

Example 3

A pigment paste was prepared in a similar manner to Comparative Example 1 except that Production Example 4 was used as the pigment dispersion resin.

On the other hand, the main resin, which is one of the components of the cationic electrodeposition paint, was prepared by reacting as follows.

TABLE 7

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

EPON 828, Bisphenol A, Anchoramine 1040 were heated at 180 ° C. until the epoxy equivalent was 950. After cooling the reaction mixture to 80 ° C., 2-butoxyethanol, N-methylethanolamine and KT-24 are added. The reaction mixture was heated to 120 ° C. and maintained for 2 hours. When the epoxy equivalent is 30,000 or more, lactic acid is added to neutralize it. After holding for 1 hour, the curing agent was 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-disperse resin was measured by an autosizer (Marbourne), and found to be 186 nm. And the solid content of water dispersion was 39%.

The cationic electrodeposition paint was prepared by dissolving 1600.2 g of the cationic electrodeposition resin prepared above, 50 g of the plasticizer paraplex WP1 commercially available from Rohm & Haas, 480.2 g of the pigment paste of Comparative Examples 1 and 3 and the paint solid content of 20%. It was prepared by adding ionized water.

The electrodeposition coating liquid has a solid content of 20% and a ratio of pigment to binder of 0.3: 1.0. When the electrodeposition paint was filtered through a 400 mesh wire mesh, no aggregates were collected. Electrodeposition coating was carried out for 3 minutes at 270 V using the resulting coating composition on a cold rolled steel sheet surface treated with a zinc phosphate base treatment (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.

In order to evaluate the pigment dispersion ability and storage stability of the pigment dispersion resin prepared in the present invention, the experimental results were obtained as illustrated in Korean Patent No. 92-931, and the results are shown in Table 8 below.

TABLE 8

¹ pigment paste was disperse | distributed by Dispermet SL-703 (BYK company).

² The stability of the pigment paste (Example 7-11) prepared above was stored in a 60 ° C. oven to investigate the thermal stability. After thermal storage of the pigment paste, the figure shows the gelation time.

³ One month after the production of the paint, the coating liquid (2 kg in total) was filtered through a 400 mesh wire mesh (800 cm 2 area). The resulting residue was dried at 110 ° C. for 3 hours and weighed.

◎ less than 1g

O 1-4g

△ 4-10g

X 10g or more

⁴ After 1 month of paint production, the substrate was immersed in the paint liquid either vertically or horizontally. Electrodeposition coating was performed as defined, and the resulting cured film was visually inspected to count the number of needle holes and aggregates per 100 cm 2.

◎ 1 or less

O 1-5

△ 5-20

X 20 or more

As described in Table 8 above, the products prepared according to the present invention have an easy progress in their rheology, form a defect free film in both deposition and crosslinking reactions, and do not adversely affect the properties of the crosslinked film. Therefore, even if the composition of the pigment used is changed, it is possible to produce a paste of pigment that meets a variety of practical requirements, and has storage stability and excellent pigment dispersibility to meet practical requirements in both concentrated and dilute forms. .

That is, the present invention introduces a beta hydroxyalkyl carbamate as a hydrophilic group contained in the resin for dispersion, thereby imparting a steric stabilizing effect to the resin for dispersion to improve pigment dispersion and storage stability.

Claims (8)

60 to 98% by weight of polyepoxyamine derivative derived from a mixture of a polyepoxide compound and a polyamine derivative having at least one active hydrogen or a secondary amine, and 2 to 40% by weight of a cyclic carbonate represented by the following formula (2) It is prepared by neutralizing the amine group present in the reaction resin with 5 to 50 parts by weight of an organic acid based on 100 parts by weight of the resin obtained by the reaction, The polyepoxide compound is a beta hydroxyalkyl carbamate modified pigment dispersion resin, characterized in that it has an epoxide equivalent of 180 to 2000 per molecule and at least two 1,2-epoxide groups; Formula 2

Here, R ₁ , R ₂ , R ₃ and R ₄ are the same as or different from each other, hydrogen, methyl group or ethyl group. The beta of claim 1, wherein the polyepoxide compound is selected from the group consisting of polyglycidyl ethers of polyphenols, polyglycidyl ethers of aromatic polyols, noblel resin derivatives, and polyphenol resin derivatives. Resin for hydroxyalkyl carbamate modified pigment dispersion. The method of claim 1, wherein the polyamine derivative having at least one active hydrogen constituting the polyepoxyamine derivative is a hydroxyalkyl carbamate modified pigment dispersion, characterized in that the ketimine derivative having at least one secondary amine Suzy. The beta hydroxyalkyl carbamate-modified pigment dispersion resin according to claim 3, wherein the ketimine derivative is a derivative obtained by blocking primary amine of a polyamine derivative having at least one secondary amine with a ketone. The method of claim 1, wherein the reaction between the polyepoxyamine derivative and the cyclic carbonate is carried out at 20 ~ 90 ℃, beta hydroxy characterized in that the cyclic carbonate reacted by 2 to 100% based on the number of moles of primary amine Alkyl carbamate modified pigment dispersion resin. The beta hydroxyalkyl carbamate-modified pigment dispersion resin according to claim 1, wherein the organic acid is acetic acid, formic acid or lactic acid. The beta hydroxyalkyl carbamate-modified pigment dispersion resin according to claim 1, wherein the salt group per 1 g of the resin solid content obtained by neutralizing the amine group with the organic acid is contained in the milli equivalent of 0.20 to 1.50. In the anion electrodeposition coating composition containing a pigment dispersion obtained by dispersing a pigment with a cationic electrodeposition resin and a resin for dispersing a pigment, the resin for dispersing the pigment is according to claim 1, 2, 4, 5, or 5 Cationic electrodeposition coating composition, characterized in that the resin for betahydroxy alkyl carbamate modified pigment dispersion according to any one of claims 7 to 9.