KR100501068B1 - cationic electro-deposition paint composition, method of forming the cationic electro-deposition paint composition, pigment-paste composition and electro-deposition paint having the pigment-paste composition - Google Patents

Abstract

Cationic electrodeposition coating compositions, methods for their preparation and pigment paste compositions and electrodeposition coatings comprising the same are disclosed. The low temperature hardening type cationic electrodeposition paint comprises a cationic electrodeposition coating composition comprising 93 to 98% by weight of a cationic electrodeposition resin dispersion and 2 to 7% by weight of a cationic microgel, 15 to 30% by weight of a pigment grinding vehicle, and 3 to 7% by weight of a bismuth compound. It contains the pigment paste composition to contain. The coating film formed by using the paint comprising the above compositions is particularly excellent in corrosion resistance even when cured at low temperature, excellent resistance to oil and corrosion resistance at corners, and does not contain heavy metals such as lead and tin in the dry coating film. .

Description

Cationic electro-deposition paint composition, method of forming the cationic electro-deposition paint composition, pigment-paste composition and electro-deposition paint having the pigment- paste composition}

The present invention relates to a cationic electrodeposition coating composition, a method for preparing the same, a pigment paste composition, and an electrodeposition coating including the same. More particularly, the present invention relates to a cationic microgel as a rheology controller for reducing the flowability of paint. The present invention relates to a cationic electrodeposition coating composition comprising a), a method for producing the same, and a pigment paste composition containing no heavy metal and an electrodeposition coating containing the same.

In the painting industry, electrodeposition coating has higher efficiency of use of paint compared to brush painting or spray painting, has excellent resistance to corrosion, and uses water as a solvent to minimize environmental pollution. Widely used in industrial machinery and the like. Most of the epoxy based cationic electrodeposition paints used today include cationic epoxy resins to which amines are reacted and polyisocyanates blocked. Recently, domestic and overseas resins for cationic electrodeposition paints have been studied for low pollution, low toxicity and Attention is focused on the development of resource-saving paints and high-performance, high-performance polymers with a variety of uses and properties.

In general, the cationic electrodeposition coating composition is a tin compound such as dibutyl tin oxide to promote crosslinking reaction between hydroxyl group and isocyanate group and lead compound as an anticorrosive pigment to improve corrosion resistance. (lead compound) is included.

However, the lead compounds are regulated for their use as substances causing environmental pollution around the world. As an example of the regulation on the use of lead, in Japan, in July 1996, the Automobile Industry Association proposed an autonomous target for reducing the use of lead (Pb) in automobiles based on the Ministry of Trade's guidelines. Is reducing the use of lead by creating a self-regulated proposal called [SHREDDER DUST]. In addition, in the EU, legislation has been proposed to prohibit shredding, landfilling, and incineration of vehicles containing hazardous substances (lead, cadmium, mercury, etc.) with respect to disposal of used vehicles after 2003.

Therefore, studies are being actively conducted to reduce or remove harmful substances such as lead (Pb) and tin from the dry coating of the electrodeposition coating composition in accordance with the global environmental pollution regulation trend.

In US Pat. No. 5,908,912 (issued to Kollah, et al), as a reaction catalyst of a cationic electrodeposition coating composition, a salt of a carboxylic acid containing a bimuth compound and an amine is applied as a catalyst to a pigment paste and dried. The technical content of removing lead in a coating film is disclosed. However, the United States Patent No. 5,908,912 has a problem in that the bismuth salt (Bismuth salt) is agglomerated during storage, and the pH of the electrodeposition coating composition is low because the amount of acid applied to introduce the bismuth compound into the cationic electrodeposition coating composition Losing problems occur.

In addition, in addition to efforts to remove heavy metal compounds from the cationic electrodeposition coating composition, studies have been actively conducted to improve the corrosion resistance of the corner portions of the electrodeposition paint and to improve the creter resistance resulting from contamination by antirust oil.

In general, in the cationic electrodeposition coating method, unlike the conventional spray or brush coating method, the iron material is oxidized because the object is deposited in the electrodeposition tank containing the paint particles and electrically painted to uniformly paint the deep parts of the iron material. Rust can be effectively prevented from occurring.

However, since the cationic electrodeposition coating has uniformity in coating, the anti-corrosion property of the edge portion is greatly reduced, and thus paint particles containing resin coated on the substrate, such as steel, can be cured on the surface of the subject by heat drying. In this case, a dried coating film is formed by curing in a fluid liquid state, but at the corners, the coating film by the fluid liquid becomes very thin, so that corrosion resistance, that is, corrosion resistance, due to oxidation is weakened after curing. Therefore, the corrosion resistance of the dry coating film itself is weak through the corrosion of the edge part, and the durability of the dry coating film is reduced.

Thus, after the electrodeposition coating to prepare the anti-corrosion properties of the edge portion due to the fluidity of the liquid due to heat curing, a cationic microgel having a large molecular weight is prepared, and then added to the cationic epoxy resin aqueous dispersion of the liquid at the edge portion. Used to suppress flow. In addition, another function of the cationic microgel is used to prevent the formation of the cracking of the dry coating film represented by the oil, such as rust preventive oil introduced into the outside during electrodeposition coating.

US Pat. No. 6,054,033 (issued to Hunakoshi, et al), US Pat. No. 5,407,976 (issued to Uhlianuk) and US Pat. No. 5,120,796 (issued to Fukuchi) disclose compositions of microgels suitable for cationic electrodeposition coating compositions. In addition, US Patent No. 5,096,556 (issued to Corrigan, et al) discloses a method for preparing a microgel by mixing a reaction product obtained by addition reaction of an amine to a polyepoxide and a crosslinking agent and crosslinking the mixture.

In addition, Korean Patent Publication No. 99-60689 discloses a polyepoxide resin containing a double bond by reacting a reaction product or compound having a double bond isocyanate simultaneously with a polyepoxide resin having two or more epoxy groups, This is reacted with one or a mixture of primary, secondary amines and quaternary ammonium salts to produce a polyepoxide-amine reaction product, which is dispersed with an acid, to produce an aqueous product and to crosslink the aqueous product. A method for producing a cationic microgel aqueous dispersion by crosslinking using a zero acrylic monomer is disclosed.

However, the cationic polyepoxide-amine aqueous dispersion used in the method for producing the cationic microgel is deteriorated in the stability of the water dispersion and is badly generated such as sludge in the preparation of the cationic microgel, which is preferably applied to the paint. In addition, there is a problem that the water dispersion particle size of the cationic microgel is not uniform, causing a decrease in the appearance of the dry coating film.

It is a first object of the present invention to provide a low-temperature curable cationic electrodeposition coating composition comprising a cationic microgel capable of improving the corrosion resistance of the edge portion of a dry coating film and the ability to prevent cracking by antirust oil.

A second object of the present invention is to provide a method for producing a low temperature curable cationic electrodeposition coating composition comprising a cationic microgel.

A third object of the present invention is to provide a pigment paste composition which is applied to a cationic electrodeposition resin composition and does not contain lead and tin components in a dry coating film.

A fourth object of the present invention is to provide a low temperature hardening type cationic electrodeposition coating material which does not contain lead and tin components in a dry coating film, and which can improve the ability to prevent cracking due to corrosion resistance and rust preventive oil at the corners.

The present invention for achieving the first object, 93 to 98% by weight of the cationic electrodeposition resin dispersion; And 2 to 7 weight percent of cationic microgels.

The present invention to achieve the second object, a) 40 to 60% by weight of the cationic electrodeposited synthetic resin epoxy-amino addition reaction; 5 to 10% by weight of an amino group-containing acrylic cationic electrodeposition resin; 1-3 wt% of a fatty acid ester resin synthesized by substitution of an ester of a styrene-aryl alcohol copolymer with a fatty acid; And 30 to 50% by weight of the blocked polyisocyanate curing agent to form a cationic electrodeposition compound having a low boiling point organic solvent in the first mixing reaction, b) 55 to 65% by weight of deionized water; 0.3 to 1.5 weight percent organic acid; 1 to 5% by weight of reactants of manganese phosphate diluted with 10% concentration with organic acid; And forming a cationic electrodeposition resin dispersion by subjecting the mixture of 0.5 to 1% by weight of the cationic surfactant to the mixture of 35 to 50% by weight of the cationic electrodeposition resin compound, and c) the cationic electrodeposition resin in a reduced pressure atmosphere. Extracting the low boiling organic solvent from the dispersion; And d) mixing the cationic microgel in the cationic electrodeposition paint dispersion in which the low boiling point organic solvent is removed.

The present invention for achieving the third object, 15 to 30% by weight pigment grinding vehicle, 3 to 7% by weight of the bismuth compound; And 64 to 83% by weight of an additive.

The present invention for achieving the fourth object, the cationic electrodeposition resin composition containing 93 to 98% by weight of the cationic electrodeposition resin dispersion, 2 to 7% by weight of the cationic microgel, and 15 to 30% by weight of the pigment grinding vehicle , Bismuth compound 3 to 7% by weight; And a pigment paste composition containing 64 to 83% by weight of an additive; And deionized water.

Therefore, according to the present invention, since the low temperature hardening type cationic electrodeposition paint contains a metal salt and a cationic microgel, it is possible to increase the resistance to corrosion and antirust oil at corners and the like. In addition, since the pigment paste compound contains a bismuth compound instead of a lead-containing material, even when the coating film formed after electrodeposition coating is cured at low temperature, the chemical resistance such as corrosion resistance is particularly excellent, and the surface of the coating film, yellowing resistance, weather resistance and hardness is excellent. Improves the film properties.

Hereinafter, the present invention will be described in detail.

First, a cationic electrodeposition coating composition, a pigment paste composition, a low temperature hardening type cationic electrodeposition coating containing a cationic macrogel, and a method of preparing the same will be described.

Cationic electrodeposition coating composition comprising cationic macrogel

The cationic electrodeposition coating composition of the present invention comprises 93 to 98% by weight of the cationic electrodeposition resin dispersion, and 2 to 7% by weight of the cationic microgel.

Specifically, the cationic electrodeposition coating composition is 35 to 45% by weight of the cationic electrodeposition resin compound, 50 to 60% by weight of deionized water, 0.3 to 1.5% by weight of organic acid, 10% concentration of manganese phosphate (manganese phosphate) and phosphoric acid and deionized water 1 to 5% by weight of the reacted compound reacted, and 93 to 98% by weight of the cationic electrodeposition resin dispersion obtained from 0.5 to 1% by weight of the cationic surfactant and 2 to 7% by weight of the cationic microgel.

Here, the cationic electrodeposition resin compound is 40 to 60% by weight of an epoxy-amino addition reaction cationic electrodeposition synthetic resin, 5 to 10% by weight of an amino group-containing aric cationic electrodeposition resin, and esters of styrene-aryl alcohol copolymers and fatty acids. 1 to 3% by weight of the fatty acid ester resin synthesized by the substitution reaction, and 30 to 50% by weight of the 4 blocked polyisocyanate curing agent are obtained by mixing.

If the epoxy-amino addition-reacted cationic electrodeposition synthetic resin used to form the cationic electrodeposition resin compound is less than 40% by weight of the total weight of the cationic electrodeposition resin compound, it is not preferable because the mechanical properties of the dry coating film become weak. If it exceeds 60% by weight, it is not preferable because the preparation of the cationic pre-resin dispersion is difficult.

Accordingly, the amount of the cationic electrodeposited synthetic resin reacted with the epoxy-amino addition is 40 to 60% by weight, preferably 45 to 55% by weight.

An example of the above-mentioned material is shown in <Formula 1>.

<Chemical Formula 1> Cationic electrodeposition synthetic resins reacted with epoxy-amino addition

Examples of the acryl cationic electrodeposition resin containing the amino group include butyl acrylate, methyl acrylate, hydroxyethyl acrylate, styrene, methyl methacrylate, (N, N-dimethyl) aminoethyl methacrylate, and the like. . These are formed by copolymerizing single or two or more.

Herein, when the amount of the amino group-containing aric cationic electrodeposition resin is less than 5% by weight of the total weight of the cationic electrodeposition resin compound, it is not preferable because a dry coating film of an epoxy aric multilayer is not obtained, and 10% of the total weight of the cationic electrodeposition resin compound is used. It is not preferable to exceed the weight% because the miscibility of epoxy and acryl does not occur, which adversely affects the appearance and gloss of the dry coating. Therefore, the usage-amount of the said amino group containing acrylic cationic electrodeposition resin is 5 to 10 weight%, Preferably it is 7 to 9 weight%.

The fatty acid ester resin is synthesized by ester substitution reaction of styrene-aryl alcohol and fatty acid in order to improve the appearance spreading, pinhole and cruttering properties of the coating film formed of the low temperature hardening type cationic electrodeposition coating composition of the present invention. do.

The fatty acid ester resin has a molecular weight (weight average molecular weight) of about 2000 to 40,000, preferably about 3000 to about 30,000. In addition, when the amount of these fatty acid ester resins is less than 1% by weight, the spreadability, pinhole property and cregging property of the coating film formed of the low temperature curing type cationic electrodeposition coating composition are not improved. It is not preferable to exceed the weight% because it causes a decrease in the mechanical properties of the dry coating film such as pencil hardness.

Therefore, the amount of the fatty acid ester resin is 1 to 3% by weight, preferably 1.5 to 2.5% by weight.

The blocked polyisocyanate curing agent is used with the amino group-containing electrodeposition resin applied to form the cationic electrodeposition resin compound, which is completely blocked and mixed with the amino group-containing resin, or partially blocked to backbone with the resins mentioned. Can react. In addition, examples of the blocked polyisocyanate curing agent capable of low temperature dissociation include compounds having the following <Formula 2>.

or

Blocked polyisocyanate curing agent capable of low temperature dissociation

The blocked polyisocyanate curing agent is obtained by mixing the blocker with at least one of an aliphatic polyisocyanate and an aromatic polyisocyanate.

Here, hexamethylene diisocyanate, isophorone diisocyanate, etc. are mentioned as an example of the said aliphatic polyisocyanate, The polymethylene diisocyanate is mentioned as said aromatic polyisocyanate. These can be used individually or in mixture of 2 or more. Examples of the blocking agent include methyl ethyl ketoxime, dimethyl pyrazole, diethyl malonate, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and the like. These can also be used individually or in mixture of 2 or more.

Here, when the amount of the blocked polyisocyanate curing agent is less than 30% by weight of the total weight% of the cationic electrodeposition resin compound, the dry coating film is not preferable because physical properties such as pencil hardness and salt spray resistance occur, and the total weight% If it exceeds 50% by weight of the cationic electrodeposited resin dispersion is not only difficult to prepare, but also cause a decrease in physical properties such as impact resistance, flex resistance.

Therefore, the amount of the blocked polyisocyanate curing agent is 30 to 50% by weight, preferably 35 to 45% by weight.

The cationic microgel is obtained from a preemulsion resin formed by mixing a self-crosslinking cationic surfactant, an internal crosslinking compound, and an initiator.

Specifically, the cationic microgel is provided with a lipophilic group by reacting a semi-blocked isocyanate reacted with a hydroxyl group of a polyglycidyl epoxy resin main chain having an epoxy equivalent of 300 to 1,500 and a compound having active hydrogen. As the hydrophilic group, an isocyanate of a cationic quaternary ammonium salt neutralized with lactic acid, acetic acid or the like is provided at the terminal to provide a preparation of a self-crosslinking cationic surfactant dissolved in water. Subsequently, the micelle is formed in an aqueous medium using the self-crosslinking cationic surfactant, and then obtained from a preemulsion formed by mixing acrylic monomers.

The cationic microgel obtained by the above method has a particle size of 50 to 60 nm, a conductivity of 1300 to 1600 Pa / cm, a pH of 4.5 to 5.5, a glass transition temperature of 50 to 70 ° C., and a solid content of 33 to 37%. Have

Here, when the content of the cationic microgel is less than 2% by weight or the content of the cationic electrodeposition resin dispersion is more than 98% by weight in the total weight% of the low temperature curable cationic electrodeposition coating composition, the electrodeposited dry coating film may be formed by It is not preferable because contamination is lowered. When the content of the cationic microgel is more than 7% by weight or the content of the cationic electrodeposition resin dispersion is less than 93% by weight, the appearance of the dry coating is not preferable.

Therefore, the content of the cationic microgel included in the low temperature curing type cationic electrodeposition coating composition is 2 to 7% by weight, preferably 3 to 6% by weight.

The self-crosslinking cationic surfactants applied to form the cationic microgels include isocyanates, ethylene glycol monobutyl ethers, isocyanates of cationic quaternary ammonium salts and organic acids partially blocked with polyepoxides having an epoxy equivalent of 300 to 1500. , Deionized water and the like are mixed to form the reaction.

Here, the isocyanate of the cationic quaternary ammonium salt is reacted with ethanolamine, N-methylethanolamine, diethanolamine, N, N-dimethylethanolamine, etc. to the partially blocked isocyanate compound, acetic acid, formic acid, lactic acid Neutralized with organic acids, including phosphoric acid, sulfamic acid, and the like. The ethanolamine, N-methylethanolamine, diethanolamine and N, N-dimethylethanolamine may be used alone or in combination of two or more.

Examples of the internal crosslinking compound applied to form the cationic microgel include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate neopentyl glycol dimethacrylate, and the like. Methyl methacrylate, styrene, butyl acrylate, butyl methacrylate, isobornyl methacrylate, ethyl methacrylate, metaacrylic acid, acrylic acid, etc. are mentioned. These can be used individually or in mixture of 2 or more.

Examples of the initiator include 4,4'-azobis (4-cyanolelic acid), ammonium persulfate, sodium sulfate, 2,2-azobis (2-methylpropionic acid), 2,2'-azobisiso Butyl nitrile, 2,2'-azobis (2- (2-imidazolin-2-yl), etc. These can be used individually or in mixture of 2 or more.

Pigment Paste Composition

It can be used as a pigment paste composition by increasing the chemical resistance of the cationic electrodeposition coating including the composition of the low temperature hardening type cationic electrodeposition coating. The pigment paste composition comprises 15 to 30% by weight of the pigment grinding vehicle, 3 to 7% by weight of the bismuth compound, and 64 to 83% by weight of the additive.

The pigment grinding vehicle comprises 25 to 35% by weight of polyglycidyl ether of bisphenol A, 5 to 12% by weight of propylene glycol monomethyl ether acetate, 8 to 15% by weight of partially blocked isocyanate crosslinker, ethylene glycol monobutyl ether 25 To 40% by weight, 10 to 20% by weight of organic tertiary amine salt, and 0.1 to 5% by weight of deionized water.

In the obtained pigment grinding vehicle, if the amount of the pigment grinding vehicle is less than 15% by weight of the total weight of the pigment paste composition, the viscosity is increased when the pigment paste composition is stored, which is not preferable because the storage stability becomes weak. In addition, when the usage-amount of a pigment grinding | pulverization vehicle exceeds 30 weight%, since the fall of the water resistance, chemical resistance, etc. of the dry coating film of a cationic electrodeposition coating composition is not preferable, it is unpreferable. Therefore, the amount of the pigment grinding vehicle used is 15 to 30% by weight, preferably 17 to 25% by weight.

In addition, if the solid content ratio of the pigment grinding vehicle included in the pigment paste composition is less than 20%, the drying of the cationic electrodeposition paint is not preferable because the mechanical and chemical properties of the film are lowered. It is not preferable because the stability is lowered to cause the aggregation phenomenon.

Therefore, the ratio of solids content of the pigment grinding vehicle is 20% to 45%, preferably 25% to 35%.

Examples of the bismuth compound of the pigment paste composition include bismuth hydroxide, bismuth trioxide, bismuth oxide and the like. These can be used individually or in mixture of 2 or more. If the amount of the bismuth compound is less than 2% by weight of the total weight of the pigment paste composition, the corrosion resistance of the dry coating film of the cationic electrodeposition coating composition is deteriorated. And agglomeration phenomenon occurs during storage.

Therefore, the amount of the bismuth compound is 2 to 6% by weight, preferably 3 to 5% by weight.

Here, the pigment paste composition including the pigment grinding vehicle and the bismuth compound may be said to be the most important compound for making a paint free of lead and tin.

In addition, additives used to form the pigment paste composition in order to improve the dry coating corrosion resistance of the cationic electrodeposition paint include anticorrosive pigment, titanium dioxide (TiO ₂ ), carbon black, and deionized water. Examples of the rust preventive pigment include aluminum tri-polyphosphate hydrate, magnesium aluminum hydroxide carbonate hydrate, and the like, and these may be used alone or in combination.

Method for producing a cationic electrodeposition coating composition comprising a cationic macrogel

Method for producing a cationic electrodeposition coating composition comprising the cationic macrogel is as follows.

First, a fatty acid synthesized by a substitution reaction of 40 to 60% by weight of an epoxy-amino addition-reactive cationic electrodeposition synthetic resin, 5 to 10% by weight of an amino group-containing aric cationic electrodeposition resin, and an ester of a styrene-arylalcohol copolymer and a fatty acid A first mixed reaction of 1 to 3% by weight of the ester resin and 30 to 50% by weight of the blocked polyisocyanate curing agent is carried out to form a cationic electrodeposition resin compound present as a low boiling point organic solvent.

The low boiling point organic solvent has a boiling point of about 140 ° C. or less. And as an example of the said low boiling point organic solvent, methyl isobutyl ketone, xylene, toluene, methyl ethyl ketone, etc. are mentioned.

Then, 55 to 65% by weight of deionized water, 0.3 to 1.5% by weight of organic acid, 1 to 5% by weight of the reaction compound of manganese phosphate and organic acid diluted to a concentration of 10% and cationic surfactant 0.5 to 1 The cationic electrodeposition resin dispersion is formed by subjecting the mixed material mixed with the% by weight to 35 to 50% by weight of the cationic electrodeposition resin compound.

Next, after extracting and removing the low boiling point organic solvent which exists in the organic solvent of the said cationic electrodeposition resin dispersion liquid under reduced pressure, it is filtered by the said aqueous dispersion solution. And a cationic microgel is mixed with the cationic electrodeposition paint dispersion from which the low boiling point organic solvent is removed. As a result, a low temperature curing type cationic electrodeposition coating composition is formed.

Here, examples of the acryl cationic electrodeposition resin containing the amino group include butyl acrylate, methyl acrylate, hydroxyethyl acrylate, styrene, methyl methacrylate, (N, N-dimethyl) aminoethyl methacrylate, and the like. And they are formed alone or as two or more copolymers.

The fatty acid ester resin is an ester substitution reaction of styrene-aryl alcohol and fatty acid in order to improve the appearance spreadability, pinhole property, and crateability of the coating film formed from the low temperature curable cationic electrodeposition coating composition of the present invention. Are synthesized. The fatty acid ester resin has a molecular weight (weight average molecular weight) of about 2000 to 40,000, preferably about 3000 to about 30,000.

The blocked polyisocyanate curing agent is obtained by mixing the blocking agent with one substance selected from hexamethylene diisocyanate which is aliphatic polyisocyanate, isophorone diisocyanate and polymethylene diisocyanate which is aromatic polyisocyanate. Examples of the blocking agent include methyl ethyl ketoxime, dimethyl pyrazole, diethyl malonate, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and the like, and these may be used alone or in combination of two or more.

The blocked polyisocyanate curing agent is used in conjunction with the amino group containing electrodeposition resin that is applied to form the cationic electrodeposition resin compound. At this time, it may be mixed with the amino group-containing resin completely blocked or mixed with the amino group-containing resin partially blocked. Here, the backbone reaction may be performed when mixed with the partially blocked amino group-containing resin.

In addition, the reaction compound of manganese phosphate diluted with 10% concentration in deionized water and phosphoric acid improves the corrosion resistance of the electrodeposition-coated dry coating film of the cationic electrodeposition coating composition.

The reaction compound is prepared by neutralizing manganese phosphate diluted to a concentration of 10% by using organic acid, phosphoric acid (Phosphoric acid) or acetic acid, formic acid, lactic acid, sulfamic acid and the like.

If the content of the reaction compound is less than 1% by weight, the corrosion resistance, chemical properties, etc. of the electrodeposition-coated dry coating film is not preferable, and if it exceeds 5% by weight, after the electrodeposition coating, the curing reaction during drying is suppressed, It is not preferable because it lowers the curing density and lowers the chemical and mechanical properties.

Therefore, the content of the reaction compound accounts for 1 to 5% by weight of the total weight of the cationic electrodeposition resin dispersion, preferably 2 to 4% by weight.

And when forming a cationic electrodeposition resin dispersion liquid using the organic acid which is a neutralizing agent, it is suitable to make the neutralization rate of the amino group which exists in a cationic electrodeposition resin compound be 20 to 100%, Preferably it is 40 to 70%.

Subsequently, the low boiling point organic solvent is subjected to solvent stripping under a reduced pressure atmosphere of 30 to 90 mmHg, preferably 50 to 70 mmHg, at a temperature of 40 to 80 ° C. Then, 140 ° C. or higher produced when preparing the fatty acid ester resin synthesized by the ester substitution reaction of the epoxy-amino addition-reacted cationic electrodeposition synthetic resin, amino group-containing aric cationic electrodeposition resin, styrene-aryl alcohol copolymer and fatty acid The high boiling organic solvent remains, and low boiling organic solvents such as methyl isobutyl ketone, xylene, toluene, methyl ethyl ketone and the like are removed.

As such, by performing the solvent extraction process, the solid content of the cationic electrodeposition resin dispersion is 20 to 60% by weight, preferably 30 to 40% by weight. Further, by filtering the cationic electrodeposition resin dispersion using diatomaceous earth, a highly functional cationic electrodeposition resin dispersion having an average particle size of 60 nm or less and minimizing the organic solvent content can be obtained.

The cationic microgel is obtained from a preemulsion resin formed by mixing a self-crosslinking cationic surfactant, an internal crosslinking compound, and an initiator. Specifically, the cationic microgel obtains a lipophilic group by reacting a hydroxyl group of a polyglycidyl epoxy resin main chain having an epoxy equivalent of 300 to 1,500 and a semi-blocked isocyanate reacted with a compound having active hydrogen.

As a hydrophilic group, an isocyanate of a cationic quaternary ammonium salt neutralized with lactic acid, acetic acid, or the like is provided at the terminal to prepare a self-crosslinking cationic surfactant dissolved in water. Subsequently, the self-crosslinking cationic surfactant is dispersed in an aqueous medium to form a micelle, and then a pre-emulsion is prepared by slowly incorporating an unsaturated ethylenic acrylic monomer and an initiator into the aqueous medium containing the micelle with stirring.

Subsequently, the preemulsion is added dropwise to a seed polymer emulsion in which an acryl monomer is reacted with an aqueous medium containing a self-crosslinking cationic surfactant and an initiator. Thus, the cationic microgel is obtained. Here, as an example of the said acryl monomer, methyl methacrylate, styrene, etc. are mentioned, These can be used individually or in mixture.

The obtained cationic microgel has a self-crosslinking cationic surfactant arranged as a hydrophilic part on its particle surface, and a gelled acryl polymer of the minor part is present in the core part inside the particle.

In addition, the cationic microgel has a particle size of 50 to 60 nm, a conductivity of 1300 to 1600 Pa / cm, a pH of 4.5 to 5.5, a glass transition temperature of 50 to 70 ° C., and a solid content of 18 to 25%.

When the content of the cationic microgel in the cationic electrodeposition coating composition is less than 2% by weight, the electrodeposition-coated dry coating film is not preferable because the stain resistance of rust-prevented oil, etc. is lowered, and when it exceeds 7% by weight, the appearance of the dry coating film is rough. It is not desirable because it loses.

The cationic surfactant for forming the cationic microgel is 6 to 15% by weight of polyepoxide having an epoxy equivalent of 300 to 1,500, 3 to 7% by weight of propylene glycol monomethyl ether acetate and 2 to 6% by weight of crosslinking agent. One mixed reaction forms a first mixed reactant. Subsequently, 3 to 7% by weight of ethylene glycol monobutyl ether and 7 to 13% by weight of isocyanate of cationic quaternary ammonium salt are sequentially mixed to the first mixed reactant to form a second mixed reactant. In addition, the third mixed reaction is formed by sequentially reacting the third mixed reaction with 0.3 to 1% by weight of organic acid and 65 to 75% by weight of deionized water.

Here, examples of the polyepoxide include polyglycidyl ethers of bisphenol A, and examples of the crosslinking agent include partially blocked isocyanate compounds. The partially blocked isocyanate compound is formed by mixing and reacting any one of lower aliphatic alcohols and glycol ethers that are isocyanate blockers with aliphatic diisocyanate, and lower aliphatic alcohols and glycol ethers which are isocyanate blockers with aromatic diisocyanates. It is formed by mixing reaction.

 The isocyanate of the cationic quaternary ammonium salt is formed by reacting the amine with the partially blocked isocyanate compound followed by neutralization with an organic acid. Here, examples of the amine include ethanolamine, N-methylethanolamine, diethanolamine N, N-dimethylethanolamine, and the like. These can be used individually or in mixture of 2 or more. In addition, examples of the organic liver include acetic acid, formic acid, lactic acid, and phosphoric acid sulfamic acid. These can also be used individually or in mixture of 2 or more.

In the present invention, the arcic polymer formed in the core portion of the cationic microgel is an internal crosslinking compound for internal crosslinking of the cationic microgel. Examples of the internal crosslinking compound include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate neopentyl glycol dimethacrylate, and the like, and methyl methacrylate, styrene and butyl acryl. Elate, butyl methacrylate, isobornyl methacrylate, ethyl methacrylate, metaacrylic acid, acriic acid, etc. are mentioned. These can be used individually or in mixture of 2 or more.

 In this case, when the content of the internal crosslinking compound is less than 2% by weight, the crosslinkability of the cationic microgel is not preferable, and when it exceeds 6% by weight, sludge or the like is produced when preparing the cationic microgel. And the particle size becomes large, which is not preferable.

Therefore, the content of the internal crosslinking compound is 2 to 6% by weight, preferably 3 to 5% by weight.

Examples of suitable initiators for preparing the cationic microgels include 4,4'-azobis (4-cyanolelic acid), ammonium persulfate, sodium sulfate, 2,2-azobis (2-methylpropionic acid), 2,2'- azobisisobutylnitrile, 2,2'- azobis (2- (2-imidazolin-2-yl) propane, etc. These can be used individually or in mixture of 2 or more. .

Low Temperature Curing Cationic Electrodeposition Paint

In the present invention, the low temperature hardening type cationic electrodeposition coating includes a cationic electrodeposition coating composition containing 93 to 98% by weight of a cationic electrodeposition resin dispersion and 2 to 7% by weight of a cationic microgel, a pigment grinding vehicle 15 to 30% by weight, It comprises a pigment paste composition essentially containing 3 to 7% by weight of the bismuth compound and deionized water.

Here, the cationic electrodeposition resin dispersion is 35 to 45% by weight cationic electrodeposition resin compound, 50 to 60% by weight deionized water, 0.3 to 1.5% by weight organic acid, manganese phosphate, phosphoric acid and deionized water at a concentration of 10% It is obtained from 1 to 5% by weight of the mixed reaction compound and 0.5 to 1% by weight of the cationic surfactant.

The cationic microgel has a particle size of 50 to 60 nm, a conductivity of 1,300 to 1,600 Pa / cm, a pH of 4.5 to 5.5, a glass transition temperature of 50 to 70 ° C, and a solid content of 18 to 25%.

The low temperature hardening type cationic electrodeposition paint is formed by mixing 30 to 50% by weight of the cationic electrodeposition coating composition, 40 to 60% by weight of the pigment paste composition, and 5 to 15% by weight of the deionized water. In particular, the electrodeposition paint not only contains heavy metals such as lead and tin, but also has a property of easily curing at a temperature of 150 ° C. or less.

Here, the cationic electrodeposition coating composition and the pigment paste composition will be omitted because it is north of the above description.

Hereinafter, the synthesis examples and examples of the material to be applied to the present invention will be described in more detail.

Synthesis Example 1

Acrylic cationic electrodeposition resins were prepared using the compositions of the materials disclosed in Table 1 below.

        ingredient Parts by weight  Ethylene glycol monobutyl ether butyl acrylate styrene (N, N-dimethyl) aminoethyl methacrylate 2-hydroxyethyl acrylate methyl methacrylate isobornyl methacrylate ethylene glycol monobutyl ether azobisisobutyronitrile ethylene glycol Monobutyl ether azobisisobutyronitrile 34.7 6.229.3 5.911.8 1.8 4.1 0.9 0.7 1.9 0.7

First, 34.7 parts by weight of ethylene glycol monobutyl ether was placed in a synthetic flask and heated to 110 ° C while injecting nitrogen gas.

Then, 6.2 parts by weight of butyl acrylate, 29.3 parts by weight of styrene, 5.9 parts by weight of (N, N-dimethyl) aminoethyl methacrylate, 11.8 parts by weight of 2-hydroxyethyl acrylate, 1.8 parts by weight of methyl methacrylate, iso The 1st mixture liquid which mixed 4.1 weight part of carbonylmethacrylates was dripped at 115 degreeC over 4 hours.

And the 2nd mixture liquid which mixed 0.7 weight part of azobisisobutyronitrile and 1.9 weight part of ethylene glycol monobutyl ether was dripped over about 1 hour through the funnel.

After about 1 hour, a third mixture of 0.7 parts by weight of azobisbutyronitrile and 1.9 parts by weight of ethylene glycol monobutyl ether was added dropwise through the funnel over about 1 hour.

In this manner, the reaction was carried out for about 3 hours after completion of dropwise addition to obtain an aric cationic electrodeposition resin having an amine group of 30 to 40 and a solid content of 60.

Synthesis Example 2

The fatty acid ester resin synthesized by the ester substitution reaction of the styrene-aryl alcohol copolymer and the fatty acid was prepared using the composition of the mixture disclosed in Table 2 below.

  ingredient   Weight part  Palm oil (fatty acid) styrene-aryl alcohol copolymer xylene ethylene glycol monobutyl ether      9.9 60.3 1.9 27.9

First, 9.9 parts by weight of palm oil (fatty acid) and 60.3 parts by weight of styrene-aryl alcohol copolymer were placed in a flask, and the temperature was raised to about 140 ° C. to completely dissolve it.

The melted product was then heated to about 220 ° C. and subjected to a constant reaction to obtain a fatty acid ester resin having an acid value of 4 or less and a solid content of 70%.

Synthesis Example 3

Using the composition of the material disclosed in Table 3 below to prepare a reaction compound applied to obtain a cationic electrodeposition resin dispersion.

  ingredient   Weight part  Manganese Phosphate Phosphate Deionized Water      4.08 1.0 35.72

First, 4.08 parts by weight of manganese phosphate and 35.72 parts by weight of deionized water were added to the flask, and the temperature was raised to 60 ° C and stirred for 1 hour. This resulted in manganese phosphate with a concentration of 10%.

The reaction compound was obtained by reacting manganese phosphate having a concentration of 10% at 40 ° C. with 1.0 parts by weight of phosphoric acid for about 30 minutes.

Synthesis Example 4

To prepare a cationic electrodeposition resin compound using a composition of the material disclosed in Table 4 to obtain a cationic electrodeposition resin dispersion.

          ingredient   Weight part  EPIKOTE 828CD^{* 1}  PLACCEL 205^{* 2)}  Aric cationic electrodeposition resin containing bisphenol A methylisobutyl ketone benzyldimethylamine (N, N-dimethyl) aminoethyl methacrylate (Synthesis Example 1) Fatty acid ester synthesized by ester substitution reaction of styrene-aryl alcohol copolymer and fatty acid Resin (Synthesis Example 2) Blocked Polyisocyanate Crosslinker^{* 3}  Blocked polyisocyanate crosslinkers^{* 4} Diketamine (73% solids in methyl isobutyl ketone) N-methylethanolamine derived from diethylenetriamine and methyl isobutyl ketone       27.1 9.7 7.9 2.4 0.15 9.0        1.6       20.2 20.2 3.0        2.6

* 1) It is an epoxy resin produced by reacting epichlorohydrin and bisphenol A. It is commercially available from Kumho Shell Chemical Co., Ltd., and its epoxy equivalent is about 188.

* 2) Polycaprolactone diol commercially available from DICEL Corp. from Japan.

* 3) Blocked polyisocyanate crosslinkers were prepared from mixtures of the following components. A mixture containing polymethylene-polyphenylisocyanate and diphenylmethyl-4.4-diisocyanate (commercially available as Polymeric MDI (PAPI-135K) from HD Polyurethane Co., Ltd.) is diethylene glycol monobutyl. After half blocking with ether, the product is a polyurethane crosslinker formed by reacting trimethylol propane with a molar ratio of 3: 1.

* 4) The blocked polyurethane crosslinking agent is half blocked with isophorone diisocyanate (commercially available from DEGUSA Co.) with methylethylketoxime, and then the product is treated with trimethylol propane. It is a polyurethane crosslinking agent formed by making it react by 3: 1 molar ratio.

First, EPIKOTE 828CD ^{* 1)} 27.1 parts by weight, PLACCEL 205 ^{* two) 2} 9.7 parts by weight, bisphenol A 7.9 parts by weight and 2.4 parts by weight of methyl isobutyl ketone were mixed and introduced into the flask. It heated up at 140 degreeC.

Subsequently, after adding 0.04 weight part of benzyl dimethylamine, it heated up about 210 degreeC. Then, water was removed by performing the reaction for about 30 minutes at the temperature at which the reaction mixture was refluxed. Next, the reaction mixture from which the water was removed was cooled to about 160 ° C., held for about 1 hour and 30 minutes, and cooled to 145 ° C. to add 0.11 part by weight of benzyldimethylamine.

Subsequently, after reacting at about 145 ° C. for about 2 hours and 30 minutes, an epoxy-amino addition reacted cationic electrodeposition synthetic resin was prepared. In addition, 9.0 parts by weight of a cationic resin containing (N, N-dimethyl) aminoethyl methacrylate, styrene-arylalcohol copolymer and ester substitution of the fatty acid to the cationic electrodeposition synthetic resin reacted with the epoxy-amino addition reaction. 1.6 parts by weight of the fatty acid ester resin synthesized by the reaction was slowly added in order.

Then, 3.0 parts by weight of diketamine (73% solids in methyl isobutyl ketone) derived from diethylenetriamine and methyl isobutyl ketone at 100 to 110 ° C. and 2.6 parts by weight of N-methylethanolamine were added. Subsequently, after holding the reaction for about 1 hour at about 125 ° C., 20.2 parts by weight of each of the isocyanate crosslinkers 1) and 2) blocked at a temperature of about 90 ° C. was gradually added in that order.

Thus, the cationic electrodeposition resin compound was obtained.

Synthesis Example 5

Self-crosslinking Cationic Surfactant

First, toluene diisocyanate half-blocked with 2-ethylhexanol as a blocking agent is used as an isocyanate half-blocked to an epoxy resin having an epoxy equivalent of 980, and N, N-dimethylethanolamine is reacted with the semi-blocked toluene diisocyanate. I was.

Subsequently, the isocyanate of the cationic quaternary ammonium salt neutralized with 90% lactic acid aqueous solution was reacted and then solubilized with an aqueous medium to obtain a self-crosslinking cationic surfactant.

Synthesis Example 6

To prepare a cationic electrodeposition resin composition using a composition of the material disclosed in Table 5 to obtain a cationic electrodeposition coating composition.

          ingredient   Weight part  Cationic Electrodeposition Resin Compound (Synthesis Example 4) Reaction Compound of Acetic Acid 10% Manganese Phosphate and Phosphoric Acid (Synthesis Example 3) Cationic Surfactant^{* 1} Deionized water 39.250.453.50.5356.27

* 1) Cationic surfactant is Air Products and Chemical Inc. Commercially available as XS-139 available from.

First, 56.27 parts by weight of deionized water, 0.45 parts by weight of acetic acid (glacial acetic acid), 3.5 parts by weight of a reaction compound of 10% manganese phosphate and phosphoric acid (Synthesis Example 3), cationic surfactants ^{* 1)} 0.53 parts by weight of the flask was sequentially added. And mixed uniformly.

Subsequently, 39.25 parts by weight of the cationic electrodeposition resin compound was slowly added, followed by water oxidation by stirring at high speed. Then, the solvent extraction operation of the resultant was carried out under a temperature of about 60 ° C. and a reduced pressure atmosphere of about 60 mmHg, and then the low boiling point organic solvent was removed, followed by filtration with diatomaceous earth to give a solid content of 36% and an average particle size of 60 nm or less. An electrodeposition resin dispersion was obtained.

The organic solvent is not contained in the obtained cationic electrodeposition resin dispersion.

Synthesis Example 7

In a flask equipped with a stirrer, a thermometer and a condenser, a cationic microgel having a solid content of 23% was prepared using the composition of the substances shown in Table 6 below.

        ingredient Parts by weight  Self-crosslinking Cationic Surfactant (Synthesis Example 5) Deionized Water  Deionized acetic acid 2,2'-azobis (2- (2-imidazolin-2-yl) propane  Methyl methacrylate  Deionized Water Self-crosslinking Cationic Surfactant (Synthesis Example 5) 2,2'-Azobis (2- (2-imidazolin-2-yl) propane methylmethacrylate styrene N-butylacrylate methacrylate ethylene glycol di Methacrylate 31.3332.4 64.620.771.61 36.6 180.6152.50.3201.680.532.32.13.3

First, 332.4 parts by weight of deionized water and 31.3 parts by weight of the self-crosslinking cationic surfactant of Synthesis Example 5 were charged into a flask and heated to 80 ° C.

Subsequently, 104.6 parts by weight of deionized water, 0.77 parts by weight of acetic acid and 1.61 parts by weight of 2,2'-azobis (2- (2-imidazolin-2-yl) propane were mixed at a temperature of about 80 ° C. After the dropwise addition was completed, 36.6 parts by weight of methyl methacrylate was added dropwise for 10 minutes, followed by a holding reaction for about 20 minutes, followed by 180 parts by weight of deionized water and 2,2'-azobis (2 0.3 parts by weight of-(2-imidazolin-2-yl) propane, 152.5 parts by weight of the self-crosslinking cationic surfactant of Synthesis Example 5, 201.6 parts by weight of methyl methacrylate, 80.5 parts by weight of styrene, 32.3 parts of N-butyl acrylate An emulsion prepared by mixing parts by weight, 2.1 parts by weight of methacrylic acid and 3.3 parts by weight of ethylene glycol dimethacrylate was slowly added dropwise for 3 hours.

Subsequently, after completion of the dropwise addition, the reaction was carried out for about 2 hours to have a particle size of 50 to 60 nm, a cationic microgel having physical properties of 1450 ㎲ / cm, pH 5.3, glass transition temperature 64 ° C., and solid content of 23%. Obtained.

Synthesis Example 8

The pigment grinding vehicle applied to form the pigment paste composition was prepared using the composition of the materials disclosed in Table 7 below.

                ingredient   Weight part  EPIKOTE 3004CD^{* 1} Propylene Glycol Monomethyl Ether Acetate Partially Blocked Isocyanate Crosslinker^{* Note 2)}  Ethylene Glycol Monobutyl Ether Organic Tertiary Aluminate^{* 3}  Deionized water    29.0 10.0 12.0 33.0 14.0 2.0

* 1) Polyglycidyl ether (Epoxy equivalent 900-1200) of bisphenol A commercially available from Kumho Shell Chemical Co., Ltd. was used.

* 2) After reacting 54.3 parts by weight of 2.4-toluene isocyanate with 40.7 parts by weight of 2-ethylhexanol at 40 ° C. or less for 3 hours, 5.0 parts by weight of methyl isobutyl ketone was added and diluted to use a partially blocked isocyanate crosslinking agent. .

* 3) After 15.5 parts by weight of dimethylethanolamine and 56.7 parts by weight of partially blocked isocyanate crosslinking agent were reacted at room temperature for 2 hours, after confirming that the NCO peak disappeared at 80 ° C., 17.4 parts by weight of lactic acid (88% purity) was removed. 3.5 parts by weight of ionized water and 7.0 parts by weight of ethylene glycol monobutyl ether were added thereto, and reacted at 60 ° C. for 1 hour to obtain an organic tertiary amine salt.

First, 29.0 parts by weight of EPIKOTE 3004CD and 10.0 parts by weight of propylene glycol monomethyl ether acetate were added to a reaction flask, and the temperature was raised to 110 to 120 ° C to dissolve uniformly.

Subsequently, 12.0 parts by weight of partially blocked isocyanate crosslinking agent was added, and the reaction was carried out for 1 hour. Then, 33.0 parts by weight of ethylene glycol monobutyl ether was added thereto. The resultant was heated to 80 to 90 ° C., and 14.0 parts by weight of organic tertiary amine salt and 2.0 parts by weight of deionized water were added to maintain the reaction until the acid value was about 0.8, thereby obtaining a pigment grinding vehicle.

Here, the epoxy equivalent of the polyglycidyl ether of bisphenol A is 900-1200.

Example 1

A pigment paste composition was prepared using the composition of materials disclosed in Table 8 below.

                ingredient   Weight part  Carbon Black Titanium Dioxide Bismuth Trioxide Deionized Water Aluminum Silicate Pigment Grinding Vehicle    0.6 123.75 16.77 45.0 16.77 25.0

A mixture of 0.6 parts by weight of carbon black, 23.75 parts by weight of titanium dioxide (TiO ₂ ), 4.51 parts by weight of bismuth trioxide, 45 parts by weight of deionized water, and 16.77 parts by weight of aluminum silicate, 25 parts by weight of a pigment grinding vehicle in a bead mill The pigment paste composition was obtained by grinding to 15 micrometers or less.

Solid content of the said pigment paste composition is 50%, and solid content ratio of a pigment grinding | pulverization vehicle is 27%.

Example 2

Cationic electrodeposition coating composition prepared by mixing 3% by weight of cationic microgel of Synthesis Example 7 with 97% by weight of cationic electrodeposition resin dispersion of Synthesis Example 6, the pigment paste composition of Example 1 and deionized water were 40.6 / 9.8 / 49.5 The low temperature hardening type cationic electrodeposition paint was prepared by mixing using the mixing ratio of.

Example 3

95% of the cationic electrodeposition resin dispersion of Synthesis Example 6, the cationic electrodeposition coating composition prepared by mixing 5% of the cationic microgel of Synthesis Example 7, the pigment paste composition of Example 1 and the deionized water of 40.6 / 9.8 / 49.5 The low temperature hardening type cationic electrodeposition paint was prepared by mixing using.

Comparative Example 1

Except that the cationic microgel was not added in the pigment paste composition of Example 1, an electrodeposition paint was prepared using a pigment grinding vehicle synthesized in the same manner as in Synthesis Example 8.

Comparative Example 2

Electrodeposition was carried out using the pigment paste composition prepared in Example 1, except that no cationic microgel was added in the pigment grinding vehicle of Synthesis Example 8 and no bismuth trioxide was added to the pigment paste composition of Example 1. The paint was prepared.

Test Example and Comparative Test Example

Using electrodeposition paints obtained from Examples 2 and 3 and Comparative Examples 1 and 2, the electrodeposition coating was carried out under a coating condition of 28 minutes at a temperature of 28 ° C., an energization condition of 200 V, and 20 minutes at a heat curing temperature of 150 ° C., and the thickness was 20 μm. Phosphorus coating film was evaluated for physical properties. The physical property test results of the coating film are shown in Table 9 below. Here, the physical property evaluation using the electrodeposition paint of Example 2 corresponds to Test Example 1, and the physical property evaluation using the electrodeposition paint of Example 3 corresponds to Test Example 2. And the physical property evaluation using the electrodeposition paint of the said comparative example 1 corresponds to the comparative test example 1, and the physical property evaluation using the electrodeposition paint of the said comparative example 2 corresponds to the comparative test example 2.

                     Example Test Example 5 Test Example 6 Comparative test example 1 Comparative Test Example 2 Coating appearance ◎ ◎ ◎ ◎ Baking temperature 150 ℃ 150 ℃ 150 ℃ 150 ℃ Gloss (60 degrees gloss system) 68 67 73 87 Pencil Hardness (Mitsubishi Uni) 2H 2H 2H HB Top coat adhesion ^{* 1} ◎ ◎ △ △ Impact Resistance ^{* 2} (1/2 "x500gx50cm) OK OK OK NG Flex resistance ^{* 3} (Mandrel Conical) OK OK OK NG Salt water spray resistance ^{* 4} <0.5mm <0.5mm > 2mm > 5mm Corner Corrosive ^{* 5} Good Good Not good Not good Water resistance ^{* 6} ◎ ◎ ◎ △ Pollution Resistance ^{* 7} One No crater 18 23

* Evaluation: excellent; ◎, good; ○, normal; Δ, poor; X

* 1) Top coat adhesion: After coating the top coat on the electrodeposition coating film, the tape was tested by cross cutting 1 mm x 1 mm within 1 cm x 1 cm.

* 2) Impact resistance: It was evaluated as OK that the coating film was not broken more than four times by performing five times with a DuPont impact resistance tester.

* 3) Flexibility: Five times with a Mandrel Conical Resistance Tester, it was evaluated that no cracks were formed in the coating film more than four times.

* 4) Salt water spray resistance: 35 ° C., sprayed for 1000 hours with 5% NaCl solution, and left for 24 hours.

* 5) Corner Corrosion: After the electrodeposition coating on the knife instead of the cold rolled steel, the degree of rust on the blade after spraying for 240 hours with 35 ℃ and 5% NaCl solution was investigated.

* 6) Water resistance: After 240 hours of immersion in 50 ℃ hot water, the appearance of coating was confirmed.

* 7) Pollution resistance: Antirust oil was added to the electrodeposition paint solution, followed by electrodeposition coating.

Referring to Table 9, a fatty acid ester synthesized by ester substitution reaction of an acryl cationic electrodeposition resin (Synthesis Example 1), a styrene-aryl alcohol copolymer, and a fatty acid including (N, N-dimethyl) aminoethyl methacrylate. Cationic microgel of Example 7 in combination with the cationic electrodeposition resin dispersion of Synthesis Example 6 containing a resin (Synthesis Example 2) and a polyisocyanate crosslinker half-blocked with methylethylketoxime and containing manganese phosphate (Synthesis Example 3) The coating film formed by using the cationic resin composition of Examples 2 and 3 and the pigment paste composition containing a bismuth compound instead of lead and tin compounds formed by mixing is particularly excellent in corrosion resistance at the corners and It was confirmed that the resistance was greatly increased.

On the other hand, the coating film formed by using the cationic electrodeposition coating compositions of Comparative Examples 1 and 2 not containing these had a good appearance, but lowered the corrosion resistance of the corner portion than Examples 2 and 3, and also greatly reduced the resistance to contamination by rust-preventing oils and the like. It can be seen. In addition, it can be seen that the coating film formed from the composition of Comparative Example 2, which does not contain a bismuth compound, greatly reduced the corrosion resistance.

As such, the low-temperature-curable cationic electrodeposition paint comprising the cationic electrodeposition coating composition and the pigment paste composition according to the present invention contains a metal salt which can improve the corrosion resistance, and gelled to increase the resistance to corrosion resistance and rust-preventive oil at the corners. It contains a cationic microgel.

In addition, since the pigment paste composition included in the cationic electrodeposition paint contains a bismuth compound instead of the lead compound, the formed coating film after electrodeposition coating is particularly excellent in chemical properties such as corrosion resistance, even when cured at low temperatures. While the coating properties are improved in terms of weather resistance and hardness, other excellent properties can be maintained.

Although described with reference to the preferred embodiments of the present invention as described above, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated that it can be changed.

Claims (21)

93 to 98% by weight of cationic electrodeposition resin dispersion; And Obtained from a pre-emulsion resin formed by mixing a self-crosslinking cationic surfactant, an internal crosslinking compound and an initiator, and having a particle size of 50 to 60 nm, a conductivity of 1300 to 1600 dl / cm, a pH of 4.5 to 5.5, 50 to 2 to 7 wt% of a cationic microgel having a glass transition temperature of 70 ° C. and a solids content of 18 to 25%, The cationic electrodeposition resin dispersion is an epoxy-amino addition cationic electrodeposition synthetic resin, an amino group-containing aric cationic electrodeposition resin, a fatty acid ester resin synthesized by substitution reaction of styrene-arylalcohol copolymer with an ester of a fatty acid, and a blocked polyisocyanate curing agent. 35 to 45% by weight of the cationic electrodeposition resin compound obtained by mixing reaction; 50 to 60 weight percent of deionized water; c) 0.3 to 1.5 weight percent of organic acid; d) 1 to 5% by weight of a reaction compound in which manganese phosphate diluted with 10% concentration is reacted with phosphoric acid; And e) cationic electrodeposition coating compositions based on those obtained from 0.5 to 1.0% by weight of cationic surfactant. delete The method of claim 1, wherein the cationic electrodeposition resin compound, a) 40 to 60% by weight of cationic electrodeposition synthetic resin reacted with epoxy-amino addition; b) 5 to 10% by weight of an amino group containing acrylic cationic electrodeposition resin; c) 1 to 3% by weight of a fatty acid ester resin synthesized by substitution reaction of a styrene-aryl alcohol copolymer with an ester of a fatty acid; And d) 30 to 50% by weight of blocked polyisocyanate curing agent mixed reaction. The method of claim 1, wherein the amino group-containing arctic cationic electrodeposition resin is butyl acrylate, methyl acrylate, hydroxyethyl acrylate, styrene, methyl methacrylate and (N, N-dimethyl) aminoethyl methacrylate Cationic electrodeposition coating composition, characterized in that formed by copolymerizing at least one material selected from the group. The blocking polyisocyanate curing agent according to claim 1, wherein the blocked polyisocyanate curing agent is at least one selected from the group consisting of hexamethylene diisocyanate as aliphatic polyisocyanate, isophorone diisocyanate and polymethylene diisocyanate as aromatic polyisocyanate, A cationic electrodeposition coating composition obtained by mixing and reacting at least one selected from the group consisting of toxin, dimethylpyrazole, diethylmalonate, ethylene glycol monobutyl ether and diethylene glycol monobutyl ether. delete delete The method of claim 1, wherein the self-crosslinking cationic surfactant is an isocyanate, an ethylene glycol monobutyl ether, an isocyanate, an organic acid, and deionized water of a cationic quaternary ammonium salt partially blocked with a polyepoxide having an epoxy equivalent of 300 to 1,500. Cationic electrodeposition coating composition characterized in that it is formed by mixing reaction. The method of claim 8, wherein the isocyanate of the cationic quaternary ammonium salt is at least any one selected from the group consisting of ethanolamine, N-methylethanolamine, diethanolamine and N, N-dimethylethanolamine in the partially blocked isocyanate compound. After reacting one amine, it is formed by being neutralized with at least one organic acid selected from the group consisting of acetic acid, formic acid, lactic acid, phosphoric acid and sulfamic acid. The method of claim 1, wherein the internal crosslinking compound is ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate neopentyl glycol dimethacrylate, methyl methacrylate, styrene And butyl acrylate, butyl methacrylate, isobonyl methacrylate, ethyl methacrylate, methacrylic acid and at least one selected from the group consisting of acetic acid. The method of claim 1, wherein the initiator is 4,4′-azobis (4-cyanolelic acid), ammonium persulfate, sodium sulfate, 2,2-azobis (2-methylpropionic acid), 2,2 Cationic electrodeposition coating composition, characterized in that at least any one selected from the group consisting of '-azobisisobutylnitrile, 2,2'- azobis (2- (2-imidazolin-2-yl) propane. a) 40 to 60% by weight of cationic electrodeposition synthetic resin reacted with epoxy-amino addition; 5 to 10% by weight of an amino group-containing acrylic cationic electrodeposition resin; 1-3 wt% of a fatty acid ester resin synthesized by substitution of an ester of a styrene-aryl alcohol copolymer with a fatty acid; And forming a cationic electrodeposition resin compound present as a low boiling organic solvent by subjecting the blocked polyisocyanate curing agent to 30 to 50% by weight in a first mixing reaction. b) 55-65 weight percent deionized water; 0.3 to 1.5 weight percent organic acid; 1 to 5% by weight of reactants of manganese phosphate diluted with 10% concentration with organic acid; And forming a cationic electrodeposition resin dispersion by subjecting the mixture of 0.5 to 1% by weight of the cationic surfactant to the mixture of 35 to 50% by weight of the cationic electrodeposition resin compound. c) extracting the low boiling point organic solvent from the cationic electrodeposition resin dispersion in a reduced pressure atmosphere; And d) obtained from a pre-emulsion resin formed by mixing a low-boiling point organic solvent-free cationic electrodeposition paint dispersion with a self-crosslinking cationic surfactant, an internal crosslinking compound, and an initiator, and having a particle size of 50 to 60 nm and a particle size of 1 to 300 nm. Of a low temperature curable cationic electrodeposition coating composition comprising the steps of mixing a cationic microgel having a conductivity of 1600 μs / cm, a pH of 4.5 to 5.5, a glass transition temperature of 50 to 70 ° C., and a solid content of 18 to 25%. Manufacturing method. 25 to 35% by weight of polyglycidyl ether of bisphenol A; b) 5-12 wt.% propylene glycol monomethyl ether acetate; c) 8 to 15 weight percent of partially blocked isocyanate crosslinkers; d) 25 to 40% by weight of ethylene glycol monobutyl ether; e) 10-20% by weight of organic tertiary amine salt; And f) 15 to 30 weight percent of a pigment grinding vehicle obtained from 0.1 to 5 weight percent of deionized water; 3 to 7 wt% of at least one bismuth compound selected from the group consisting of bismuth hydroxide, bismuth trioxide and bismuth oxide; And Antirust pigments and titanium dioxide (TiO ₂ ), carbon black and dealuminate, either of aluminum tri-polyphosphate hydrate, magnesium aluminum hydroxide carbonate hydrate or mixtures thereof Pigment paste composition comprising 64 to 83% by weight of an additive containing ionized water. delete delete delete A cationic electrodeposition coating composition containing 93 to 98% by weight of a cationic electrodeposition resin dispersion and 2 to 7% by weight of a cationic microgel; Pigment paste compositions; And deionized water, The cationic electrodeposition resin dispersion is 35 to 45% by weight of the cationic electrodeposition resin compound; 50 to 60 weight percent of deionized water; 0.3 to 1.5 weight percent organic acid; 1 to 5% by weight of a reaction compound in which 10% manganese phosphate and phosphoric acid and deionized water are mixed and reacted; And from 0.5 to 1 weight percent of cationic surfactant, The cationic microgel has a particle size of 50 to 60 nm, a conductivity of 1300 to 1600 Pa / cm, a pH of 4.5 to 5.5, a glass transition temperature of 50 to 70 ° C., and a solid content of 18 to 25%. Pigment paste composition 25 to 35% by weight of polyglycidyl ether of bisphenol A; b) 5-12 wt.% propylene glycol monomethyl ether acetate; 8-15% by weight of partially blocked isocyanate crosslinkers; 25 to 40% by weight of ethylene glycol monobutyl ether; 10 to 20 weight percent of organic tertiary amine salt; And at least one selected from the group consisting of 15 to 30% by weight of a pigment grinding vehicle obtained from 0.1 to 5% by weight of deionized water and bismuth hydroxide, bismuth trioxide and bismuth oxide. Antirust pigment and titanium dioxide, which are any one of 3 to 7% by weight of bismuth compound, aluminum tri-polyphosphate hydrate, magnesium aluminum hydroxide carbonate hydrate or a mixture thereof A low temperature hardening type cationic electrodeposition paint comprising (TiO ₂ ), 64 to 83% by weight of an additive containing carbon black and deionized water. delete delete 18. The low temperature hardening type cationic electrodeposition paint according to claim 17, wherein the solid content ratio of the pigment paste composition is 40 to 60%, and the solid content ratio of the pigment grinding vehicle of the pigment paste composition is 20 to 40%. The method of claim 17, wherein the cationic electrodeposition coating composition is 30 to 50% by weight, the pigment paste composition is 40 to 60% by weight, the deionized water is a low temperature hardening type cationic electrodeposition paint, characterized in that 5 to 15% by weight. .