KR100446702B1 - Low temperature curing and yellowing-free water dispersive resin composition comprising two different kinds of water dispersive polyurethane polyester polyol resins as main resin and water dispersive blocked polyisocyanate as curing resin, and water-soluble paint composition containing the resin composition - Google Patents

Abstract

PURPOSE: Provided are a water dispersive resin composition and a water-soluble paint composition containing the resin composition which can be cured at a low temperature, is free from yellowing and imparts a high impact resistance to a coating. CONSTITUTION: The water dispersive resin composition comprises a main resin which is a mixture of a water dispersive polyurethane polyester polyol resin containing 0.3-10 % (as solid component) polyethylene glycol having polyethylene oxide group and having an acid number of 16-36 mg KOH/g before the neutralization by dimethylol propionic acid, a OH number of 60-120 mg KOH/g and a weight average molecular weight of 3,000-6,000, and a water dispersive polyurethane polyester polyol resin containing 0.3-10 % (as solid component) polyethylene glycol and having an acid number of 13-24 mg KOH/g before the neutralization by dimethylol propionic acid, a OH number of 30-60 mg KOH/g and a weight average molecular weight of 10,000-25,000, in a ratio of 2:1 to 4:1 by solid component weight; and a curing resin which is a water dispersive blocked polyisocyanate containing 4-15 wt% of a blocked isocyanate group (-NCO) and having an acid number of 25-50 mg KOH/g before the neutralization by dimethylol propionic acid and a weight average molecular weight of 1,500-5,000. The ratio of the hydroxyl group of the main resin and the isocyanate group of the curing resin is 1:1.4 to 1:0.75 by equivalence and 50:50 to 85:25 by solid component weight. The water dispersive blocked polyisocyanate is prepared by reacting a polyvalent alcohol and a polyvalent acid to prepare a polyester polyol; mixing it with an anionic group, a polyvalent alcohol and a co-solvent; adding a polyvalent isocyanate; adding a blocking agent when the content of the remaining isocyanate reaches 4-16 wt% of the solid component content of the polyurethane polymer; and adding a neutralizer to neutralize the mixture, wherein the neutralizer is 3,5-dimethylpyrazole, 3-methylpyrazole, 4-nitro-3,5-dimethylpyrazole or 5-bromo-3,5-dimethylpyrazole, and the content is 4-12 wt% based on the total water dispersive blocked resin composition.

Description

Low Temperature Curing and Non-yellowing Water Soluble Coating Composition

The present invention relates to a coating composition using a water-dispersible polyurethane main resin composition and a water-dispersible block polyisocyanate cured resin composition which are cured at low temperature and which are non-yellowing and impart high impact resistance to the coating film. Improving chemical resistance and curing at low temperatures by incorporating additives, co-solvents, pigments and extender pigments into the resin composition consisting of water-dispersed polyurethane polyester polyol resins and water-dispersed blocked polyisocyanate cured resins for imparting softening properties And it relates to a coating composition which is non-yellowing and improved the adhesion and impact properties of the electrodeposition base and top.

The issue of global environmental preservation, which has recently been gaining global attention, is being addressed as a major issue in the international community, and the regulatory laws are already enacted in different countries, and the recent rise of the green round represents its seriousness. Developed countries have developed and applied anti-pollution paints, that is, low solvent paints, waterborne paints, powder paints and special hardening paints.In the case of automotive paints, since 1985, water-soluble metallic top coats have been applied to seal lines in Europe. The ratio is increasing rapidly, and the trend is spreading to the United States and Japan, so Korea is expected to apply water-soluble paints in the near future.

However, when the water-soluble resin for paints, which has been developed in the past and present, is applied to paints, they are significantly inferior to the useful paints currently in use in terms of hiding power, gloss, rust resistance, chemical resistance, adhesion, impact properties, and the like. In addition, it could not satisfy the needs of consumers in terms of coating appearance, such as workability, spray coating conditions, high temperature baking conditions, paint storage properties, and yellowing when recured to high temperatures.

For example, US Pat. No. 4,673,753 relates to an unsaturated polyester resin having a water-soluble polyalkylene glycol, and has a problem in that yellowing occurs at high temperature curing with an amino resin (170 ° C., 1 hour), US Pat. No. 3,870,684, Nos. 3,905,929, 4,028,313 and 4,764,553 are water-dispersed polyurethane urea resins formed by chain extension of the remaining isocyanate groups of a polyurethane prepolymer formed by a urethane reaction of a main chain with a polyester and a urethane reaction of a side chain with a polyethylene oxide. However, it is difficult to soften or form a coating film due to the lack of a curing functional group during curing reaction with an amino resin or an aqueous dispersion polyisocyanate resin applied in the present invention. Appear to be inadequate The. In addition, in the case of US Pat. No. 4,608,413, which attempts to compensate for this problem and overcome the acid resistance problem of the amino resin as a curing agent, a method of curing a water-dispersible polyurethane resin containing a hydroxyl group with a water-soluble block polyisocyanate resin has been adopted. In addition, due to the excessive hardness of the coating, the impact of the coating was rather deteriorated, and due to the incorrect selection of the blocking agent, the yellowing phenomenon of the coating could not be overcome at high temperature curing (170 ° C, 1 hour), and the low temperature storage property and pH of the resin It was difficult to control.

Therefore, in the present invention, in order to solve such a problem, two types of water-dispersed polyurethane polyester polyol resins and water-dispersed block polyisocyanate resins were introduced for curing thereof, and the carboxyl group of the polymer chain was suppressed to the maximum. Also, nonionic dispersant was used to maximize the workability and dispersibility of the paint, and polysiloxane additives were applied to prevent the defoaming and smoothness of the paint and smoothing and cratering. It eliminates popping phenomena caused by the difference in evaporation rate, and by using the proper mixture of polyacrylic emulsion type and polyurethane type fluidity regulator and fused silica type middle agent, it prevents the paint from flowing down and further maximizes smoothness. Composition and containing it The purpose is to provide an aqueous paint.

Therefore, in the present invention, polyethylene glycol containing a polyethylene oxide group for the purpose of imparting hardness to the coating film as the main resin is 0.3 to 10.0% as a solid content, and the acid value is 16 to 36 mgKOH / g before neutralization by propionic acid, and the hydroxyl value is 60. Water-dispersed polyurethane polyester polyol resin having a weight average molecular weight of -120 mgKOH / g and a weight average molecular weight of 300-6000 and polyethylene glycol for the purpose of imparting softness to the coating film are 0.3 to 10% in solid content and 13 to 24 mg KOH / g, a hydroxyl value of 30 to 60 mgKOH / g, a water-dispersed polyurethane polyester polyol resin having a weight average molecular weight of 10,000 to 25,000 are mixed in a solid ratio of 2: 1 to 4: 1, and as the curable resin, dimethylol propionic acid Water-dispersed block polyisos having an acid value of 25-50 mgKOH / g before neutralization, 4.0-15.0 wt% of blocked isocyanate group (-NCO) and a weight average molecular weight of 1,500-5,000 By preparing an anate, an aqueous resin composition is prepared such that the ratio of the hydroxyl group of the main resin and the isocyanate group of the cured resin is 1: 1.4 to 1: 0.75 and the solid content ratio is 50:50 to 85:25. It consists of manufacturing a water-soluble paint composition containing a pigment and an extender pigment.

The present invention will be described in more detail as follows.

A) Preparation of Water Dispersed Polyurethane Polyester Polyol Resin to Give Hardness to Coating Film

The resin is designed to include polyethylene oxide groups in the side chain and acid and hydroxyl groups in the main chain at the same time. The introduction of intramolecular polyethylene oxide groups enhances the solubility of the polymer, maintains a stable state against the electrolytic material, and maintains moisture at low temperatures. The carboxyl group of dimethylol propionic acid, which acts as a functional group to prevent the gel from forming and anionic urethane group is formed in the polymer, can be solubilized by salt formation by amine neutralization, and the aqueous dispersion does not gel at high temperatures. The polyester polyol hydroxyl group which is present at the end of the polymer, which acts as a functional group to prevent the formation of a urethane group by reacting with the remaining isocyanate group of the cured resin, is present as a functional group that forms a strong coating film.

The production method of the water-dispersed polyurethane polyester polyol resin is composed of three steps of production of polyester polyol, production of polyurethane polyester polyol prepolymer, and neutralization and solubilization. It is described in detail in the previously filed 94-037416 application patent.

B) Preparation of Water Dispersed Polyurethane Polyester Polyol Resin That Gives Softness to Coating Film

In the present invention, a high molecular weight water-dispersed polyurethane polyester polyol resin is used for the purpose of preventing impact defects due to excessive hardness improvement of the coating film by imparting a certain amount of softening property to the coating film. The carboxylic acid groups were localized in the main chain to form salts by neutralizing agents, and the molecular structure was designed such that hydroxyl groups are located at both ends of the main chain.

The production process of the water-dispersed polyurethane polyester polyol resin is also made of a polyester polyol, polyurethane polyester polyol prepolymer production and neutralization and solubilization three-step reaction, similar to the above resin for hardness. The method is described in detail in the 94-037416 application patent filed by the applicant in 1994.

The two water-dispersed polyurethane polyester polyols prepared by the method of the present invention are preferably combined in a ratio of 2: 1 to 4: 1 by solid ratio when the paint is applied, and the ratio of the water-dispersible resins is 2: 1 or less If the coating film is softened, the chemical resistance and mechanical properties are very inferior, and if it is 4: 1 or more, the coating film is increased in hardness and seriously affects the impact and adhesion when the top coat and the clear paint are applied.

C) Preparation of Water Disperse Block Polyisocyanate Resin

A water-soluble block polyisocyanate resin is used to cause a curing reaction at a predetermined temperature with the water-dispersed polyurethane polyol resins prepared by the methods of a) and b), which localizes the carboxylic acid groups in the main chain to neutralize them. The solubilization was made possible by forming a salt, and the isocyanate group was positioned at both ends of the main chain and blocked with a blocking agent, thereby designing a stable molecular structure at room temperature.

As a characteristic part of the present invention, a method for preparing a water-dispersible block polyisocyanate resin, which is a cured resin, is described in more detail as follows. I. First Step Reaction: As in the first step reaction of the water-disperse polyester polyol resin, a polyester polyol preparation step, the raw materials used and the reaction conditions are also the same as described in the 94-037416 application patent.

That is, the polyester polyol prepared in the first step reaction has a hydroxyl value of 100 to 180 mgKOH / g, preferably a hydroxyl value of 120 to 140 mgKOH / g, and has a low molecular weight of 400 to 1200, preferably 700 to 900 is good.

II. Second stage reaction: forming a blocked polyisocyanate prepolymer, in which first anionic group is an important and characteristic reaction component in ensuring the water dispersibility of the polyester polyol prepared in the first stage reaction and the present prepolymer. , And mix polyhydric alcohol. At this time, the amount of the anionic group to be used is 6 to 12% by weight of the amount of the prepolymer as a solid, preferably 8 to 10% by weight, a representative of this group is also dimethylol propionic acid. The polyhydric alcohol is as mentioned in the 94-037416 application patent.

In order to homogeneously mix the three components at 80 to 110 ° C., N-methyl-2-pyrrolidone, which is 2 to 5% by weight of cosolvent, is added. Once homogeneous mixing is found, the polyhydric isocyanate (mentioned in the 94-037416 application patent) is added over 30 minutes while maintaining the temperature at 50 ° C., and then the reaction is continued for at least 4 hours. And when the residual isocyanate content reaches 4 to 16% by weight, a blocking agent is added dropwise, the reaction is an exothermic reaction, the temperature rises to 70 ~ 80 ℃.

Blocking agents used in this reaction include caprolactam, acetone oxime, butanone oxime, cyclohexanone oxime, malonic acid-diethyl ester, acetoacetic ester, acetylacetone, 3,5-dimethylpyrazole, 3-methylpyra Sol, 4-nitro-3,5-dimethylpyrazole and 4-bromo-3,5-dimethylpyrazole, and the like. In the present invention, a method of blocking with pyrazoles is adopted.

Thereafter, the reaction is carried out at 70 to 80 ° C. for at least 1 hour, and the reaction is terminated at the point where the residual isocyanate content becomes zero. Upon completion of all reactions of the prepolymer, the blocked polyisocyanate prepolymer has 4 to 16% by weight of isocyanate groups blocked by pyrazoles, containing 6 to 12% by weight of chloride groups, and an acid value of 25 to 50 mgKOH / g. The acid value is preferably 30 to 40 mgKOH / g.

III. Third Step Reaction: The final step of the water-dispersed blocked polyisocyanate resin of the present invention is the neutralization and solubilization step.

In the present reaction, when the preparation of the prepolymer is terminated, while maintaining the temperature at 70 to 80 ° C., 3 to 7 wt% of a neutralizing agent corresponding to 85 to 100% of neutralization of the prepolymer is added over 10 minutes, and then maintained for 20 minutes. Neutralization reaction is complete | finished and water oxidation becomes possible. When neutralization is completed, the water holding 70-80 degreeC is poured into the resin over 1 hour, and if it carries out for 1 hour holding reaction, the final water dispersion block polyisocyanate resin stable at normal temperature for 6 months or more will be obtained.

The final water-soluble blocked polyisocyanate resin formed as described above has a final acid value of 1 to 9 mgKOH / g, a weight average molecular weight of 1,400 to 5,000, a resin solid content of 35 to 46%, a pH of 7.5 to 9.5, a particle size of 160 to 260 nm, and a viscosity Has C-D in a bubble viscometer.

In the present invention, when the cured resin according to the above method c) and the water-dispersible polyurethane polyester polyol main resins according to the method a) and b) are applied to the paint, the isocyanate of the cured resin was blocked at 130 to 150 ° C. The molecular structure of the resins was designed such that the blocking agent was volatilized and the remaining isocyanate groups reacted with the hydroxyl groups of the water-dispersed polyurethane polyester polyol resin to form new urethane groups, thereby completing the coating film formation.

In more detail, the present curing system, when applied to the water-soluble intermediate and the water coating for automobiles using the water-dispersion resin of the present invention, prepared by using the water-dispersible resins as the main agent and the curing agent on the electrodeposited coating One-component water-soluble paints are air sprayed or bell-coated to 30 to 45 microns with a dry coating film and maintained at a setting time of 5 minutes at room temperature, then flashed off at 80 ° C. for 5 minutes using an IR oven. (Flash Off) and heat-cured at 130-150 ℃ for 20-30 minutes in a convection oven.

Therefore, when applying the paint of the water-dispersed polyurethane polyester polyol resin and the water-dispersed blocked polyisocyanate resin obtained by the above reaction process, the ratio of the hydroxyl group of the main resin and the isocyanate group of the cured resin is 1: 1.4 to 1: 0.75, that is, By combining the solids of the resins so as to be 50:50 to 85:25, it is possible to form a high impact resistant coating film for automobiles.

In the present invention, a coloring pigment is added to the water-soluble paint prepared by using the water-dispersible resins to facilitate water solubility and provide a more beautiful color, and also to provide a strong property by protecting the paint film, and to increase the paint film. In order to improve the smoothness, spherical sieving pigments are added, which must be ground to an atomized size of 5 microns or less through the milling process. This is because the water-soluble paint is made of water, and since the evaporation rate is very slow, the total surface area of the pigment must be increased to increase the evaporation rate of the water.

Pigments used in the water-soluble paints of the present invention include inorganic pigments such as titanium dioxide and carbon black, and extender pigments such as barium sulfate and magnesium silicate. 15 to 30% by weight of the water-soluble paint of the present invention is used. If the pigment used is less than 15% by weight, it causes the hiding power of the coating film and the hardening of the coating film. If the pigment is more than 30% by weight, the interlayer adhesion between the coating films, the gloss and the clarity of color are lowered, and the mechanical properties are deteriorated. It causes a price increase. In addition, the ratio of the extender pigment of the present invention is characterized in that the weight ratio of barium sulphate and magnesium silicate is 1: 1 to 3: 1, which facilitates water solubility and improves the smoothness and appearance of the coating film. It is the composition ratio that can be done.

In addition, in the present invention, an additive is used in order to sufficiently exhibit the function of the water-soluble paint. In the present invention, the following four additives are used.

First, in the coating composition of the present invention, a dispersant is introduced into a mill-base in order to efficiently disperse the pigment into two types of water-dispersible resins in a uniform and stable state. In the present invention, a nonionic dispersant suitable for an inorganic pigment system is prepared. It is used, the amount of use is 0.5 to 1.5% by weight based on the total water-soluble coating composition. If the dispersant used is less than 0.5% by weight, the pigment dispersion efficiency is greatly reduced, causing re-agglomeration of the pigment, which in turn causes cratering in the coating film, poor polishing resistance and gloss of the coating film. If it is more than% by weight, the excessive increase in transparency causes a decrease in hiding power of the coating film and a price increase.

Secondly, in the coating composition of the present invention, most of the solvent is composed of water, and when the mill-base or post-treatment, foam generation is a big problem. Therefore, in the present invention, in order to eliminate such a problem, a polysiloxane antifoaming agent is used in the mill-base step, and the amount thereof is 0.05 to 0.5% by weight based on the total water-soluble coating composition. In the case of the antifoaming agent, it is diluted in water to be added to the mill-base, and exceeds the above-mentioned amount of usage, which causes severe cratering.

Third, when the water-soluble paint in the coating composition of the present invention to form a coating film, the polysiloxane-based smoothing agent is added in the post-treatment step to smooth the coating film and improve the wetting property of the body. The usage-amount shall be 0.1 to 1.0 weight% with respect to all the water-soluble coating compositions. In the case of the smoothing agent, the surface tension of the paint is lowered to improve the smoothness of the coating and the wettability with the base. However, the leveling agent does not exceed the range of the above-mentioned amount used in the manufacture of the paint because it provides a cause of foaming. Do not use it after diluting with water to be added to the trailing edge.

Fourth, the thickeners used in the paint composition of the present invention have a high viscosity at the low shear rate, such as during the storage of the paint to prevent the precipitation of the pigment, and at a medium shear rate, such as paint supply line, the viscosity is rapidly reduced to paint transfer In high shear rate conditions such as during painting work, the viscosity is extremely low to give the best atomization behavior, and when the paint is attached to the substrate, the shear rate is returned to a very low condition, so the viscosity increases immediately and the paint The flow of and control of the flow of pigment particles is controlled. In the present invention, a fused silica type thickener and a polyacrylic emulsion type and a polyurethane type fluidity regulator are used. The fused silica type thickener and fluidity regulator are 1: 1 to 4.5: 1 in solid content ratio, and are added at 1.0 to 3.0% by weight based on the total water-soluble coating composition. The fused silica type thickener is added to the mill-base. In principle, the fluidity regulator is post-addition.

In the water-soluble coating composition of the present invention, butyl glycol and butyl carbitol are added as a cosolvent, and the role of the cosolvent greatly improves the smoothness of the coating film, lowers the minimum film forming temperature, and smoothes the atomization of the paint during painting. Not only does it contribute significantly to the volatilization of the solvent. In addition, because it mixes very well with water and water-dispersible resins at room temperature, it contributes greatly to reducing the viscosity of the paint. The amount of the cosolvent used in the present invention is 4 to 9% by weight based on the total water-soluble coating composition.

The following Preparation Examples, Examples and Comparative Examples more specifically describe the manufacturing process, constituents, efficacy and effects of the water-dispersible resin compositions of the present invention and the paints thereof, but limit the scope of the present invention. It is not.

Production Examples 1 to 5 are methods for producing polyester polyols of main resins and cured resins, and Production Examples 6 to 8 are methods for producing water-dispersed polyurethane polyester polyols which are main resins for the purpose of hardening the coating film. 9-10 is a manufacturing method of the water-dispersed polyurethane polyester polyol which is a main resin for the purpose of providing softening property to a coating film, manufacture examples 11-12, the manufacturing method of the water-disperse block polyisocyanate which is cured resin, and Examples 1-5 are It relates to the production of paints having different composition ratios by using a water-dispersible main resin and a curing agent prepared in the above production example.

In addition, in order to evaluate the effect of the water-soluble coating composition of the present invention in detail, after preparing a comparative example with different components and ratios, a coating film was formed and various states were evaluated to obtain the results as shown in [Table 1]. In particular, the present invention produced through the examples showed excellent effects in terms of all evaluation items.

Preparation Example 1

996.8 parts by weight of isophthalic acid, 710.4 parts by weight of adipic acid, 1374.8 parts by weight of neopentyl glycol, 241.8 parts by weight of trimethylol propane and 3.4 weights of tin-based catalyst as a catalyst in a reactor equipped with a stirrer, a thermometer, a nitrogen injection pipe, a separator and a cooler Buy wealth. The temperature is gradually raised while stirring at a rate of 200 rpm under nitrogen injection, and the temperature is raised to 200 ° C. and maintained. This reaction is a condensation reaction, the water is drawn out through the separator, and the reaction is controlled so that the refractive index of the dehydrated water is 1.3340 or less. When the acid value reaches 3 mgKOH / g during the reaction, the speed of the stirrer is increased to 350 rpm and the nitrogen is excessively supplied by 75 mm Hg for 10 minutes. Thereafter, the reaction is terminated when the acid value falls below 1mgKOH / g. The polyester polyol produced by this reaction had a hydroxyl value of 193 mgKOH / g, a hydroxyl group of 5.84 wt%, and a molecular weight of 709. And the content of the trihydric alcohol included at this time is 7.3% by weight.

Preparation Example 2

498.4 parts by weight of isophthalic acid, 359.5 parts by weight of adipic acid, 593.7 parts by weight of neopentyl glycol, 161.0 parts by weight of trimethylolpropane, and 1.6 parts by weight of Passcat are used as a catalyst in a reactor installed as in Preparation Example 1. After the reaction process is the same as in Preparation Example 1. After the reaction was completed, the polyester polyol prepared by the present reaction had a hydroxyl value of 162 mgKOH / g, a hydroxyl group of 4.9% by weight, and a molecular weight of 980. And the content of the trihydric alcohol included at this time is 10.0% by weight.

Preparation Example 3

498.4 parts by weight of isophthalic acid, 350.7 parts by weight of adipic acid, 593.7 parts by weight of neopentyl glycol, 201.3 parts by weight of trimethylolpropane and 1.7 parts by weight of Passcat as a catalyst are used in a reactor installed as in Preparation Example 1. After the reaction process is the same as in Preparation Example 1. When the reaction is complete, the polyester polyol prepared by the present reaction has a hydroxyl value of 174 mgKOH / g, 5.3 wt% of hydroxyl group, and a molecular weight of 919. And the content of the trihydric alcohol used at this time is 12.3% by weight.

Preparation Example 4

830.7 parts by weight of isophthalic acid, 241.0 parts by weight of adipic acid, 37.0 parts by weight of phthalic anhydride, 797.5 parts by weight of 1,6-hexanediol, 156.5 parts by weight of trimethylolpropane and 2.0 parts by weight of Passcat as a catalyst in a reactor installed as in Preparation Example 1. use. After the reaction process is the same as in Preparation Example 1. When the reaction is complete, the polyester polyol prepared by the present reaction has a hydroxyl value of 99 mgKOH / g and a 3.0 wt% hydroxyl group, and has a molecular weight of 1787. And the content of the trihydric alcohol used at this time is 7.6% by weight.

Preparation Example 5

642.9 parts by weight of adipic acid, 709.1 parts by weight of 1,6-hexanediol, and 1.4 parts by weight of Passcat are used as a catalyst in a reactor installed as in Preparation Example 1. After the reaction process is the same as in Preparation Example 1. When the reaction is complete, the polyester polyol prepared by the present reaction has a hydroxyl value of 134 mgKOH / g, a 4.1 wt% hydroxyl group, and a molecular weight of 840.

Preparation Example 6

In a newly installed reactor (stirrer, thermometer, nitrogen injection tube, cooler) 1465.0 parts by weight of polyester polyol of Preparation Example 1, 20.0 parts by weight of polyethylene glycol (molecular weight 400), 94.0 parts by weight of dimethylol propionic acid, N-methyl-2 -163.5 parts by weight of pyrrolidone and 1.8 parts by weight of dibutyltin dilaurate were injected with nitrogen under a nitrogen injection, and the temperature was raised to 100 ° C. such that the components were homogeneously mixed. When the components are completely mixed to a transparent state, the temperature is lowered to 70 ° C. and 644.0 parts by weight of acetone are added, and 280.0 parts by weight of hexamethylene diisocyanate is added while maintaining 65 ° C. The reaction is then continued for at least 3 hours under the same conditions. The end point of the reaction is set at the point where the isocyanate content becomes zero. Upon completion of the reaction, a prepolymer having a hydroxyl value of 68.0 mgKOH / g and an acid value of 21.2 mgKOH / g is prepared. In order to make the prepolymer into an aqueous dispersion, 44.0 parts by weight of dimethylethanolamine was added to the prepolymer maintained at 65 ° C. over 15 minutes, and the reaction was carried out for 15 minutes. Thereafter, the neutralized prepolymer was added to the vessel containing 1889.0 parts by weight of 40 ° C. over 10 minutes, and dispersed at high speed (1000 to 2000 rpm) for 30 to 60 minutes to form a stable aqueous dispersion. However, since the hydrophobic dispersion contains a certain amount of acetone, if the pressure is reduced at 10 to 50 cmHg for 60 minutes while maintaining a temperature of 65 to 75 ° C. and a stirring speed of 300 rpm, the final product has stability of 1 year or more at room temperature. A water dispersion polyurethane polyester polyol resin is obtained. The thus obtained water-dispersed polyurethane polyester polyol resin had a solid content of 47.0% by weight, a final acid value of 6.2 mgKOH / g, a hydroxyl value of 68.0 mgKOH / g, a pH of 7.1, a viscosity of G, a particle size of 85 nanometers, and surface tension. It is a stable water dispersion resin of 51 dyne / cm.

Preparation Example 7

1414.0 parts of polyester polyol of Preparation Example 2, 30.0 parts by weight of polyethylene glycol, 92.0 parts by weight of dimethylol propionic acid, 146.3 parts by weight of N-methyl-2-pyrrolidone and a catalyst in a newly installed reactor with dibutyltin dilaurate 1.7 weight part was injected under nitrogen injection and stirred in the same manner as in Preparation Example 6.

When the reactants are homogeneously mixed, the mixture is cooled and charged with 601.6 parts by weight of acetone, and then 183.1 parts by weight of hexamethyl diisocyanate, and the reaction process is the same as in Preparation Example 6. Upon completion of the reaction, a prepolymer having a hydroxyl value of 70.3 mgKOH / g and an acid value of 22.4 mgKOH / g is formed. In order to make the present prepolymer into an aqueous dispersion, 48.9 parts by weight of dimethylethanolamine was added to the present prepolymer maintained at 65 ° C. over 15 minutes, and the reaction was carried out for 15 minutes. Thereafter, the neutralized prepolymer was added to a vessel containing 1743.2 parts by weight of distilled water at 40 ° C., and the procedure was the same as in Preparation Example 6. The water-dispersed polyurethane polyester polyol thus obtained had a solid content of 47.0 wt%, a final acid value of 4.4 mgKOH / g, a hydroxyl value of 70.3 mgKOH / g, a pH of 7.3, a viscosity of a bubble viscometer, a particle size of 99 nanometers, and a surface tension of 53 dyne /. It is a stable water dispersion resin which is cm.

Preparation Example 8

1448.0 parts by weight of polyester polyol of Preparation Example 3, 35.0 parts by weight of polyethylene glycol, 94.0 parts by weight of dimethylol propionic acid, 151.2 parts by weight of N-methyl-2-pyrrolidone and a catalyst in a newly installed reactor with dibutyltin dilaurate 1.8 parts by weight was added under nitrogen injection, followed by stirring in the same manner as in Preparation Example 6. When the reactants are homogeneously mixed, the mixture is cooled to 70 ° C., 662.0 parts by weight of acetone, and 200.0 parts by weight of hexamethylene diisocyanate are added over 30 minutes. Thereafter, the reaction process is the same as in Preparation Example 6. Upon completion of this reaction, a prepolymer having a hydroxyl value of 71.4 mgKOH / g and an acid value of 22.1 mgKOH / g is formed. In order to make the present prepolymer into an aqueous dispersion, 50.0 parts by weight of dimethylethanolamine was added to the present prepolymer over 15 minutes, and the reaction was carried out for 15 minutes. Thereafter, the neutralized prepolymer was added to a vessel containing 1802.7 parts by weight of distilled water at 40 ° C., and the procedure was the same as in Preparation Example 6. The water-dispersed polyurethane polyester polyol thus obtained had a solid content of 47.0 wt%, a final acid value of 4.4 mgKOH / g, a hydroxyl value of 71.4 mgKOH / g, a pH of 7.5, a viscosity of F, a particle viscosity of 108 nanometers, and a surface tension of 54 dyne /. It is a stable water dispersion resin which is cm.

Preparation Example 9

600.0 parts by weight of polyester polyol of Preparation Example 4, 20.0 parts by weight of polyethylene glycol, 24.0 parts by weight of dimethylol propionic acid, 82.9 parts by weight of N-methyl-2-pyrrolidone and 0.7 weight of dibutyl tin dilaurate in the newly installed reactor The part was charged under nitrogen injection and stirred in the same manner as in Preparation Example 6. When the reactants are homogeneously mixed, 278.4 parts by weight of acetone is added, 52.0 parts by weight of hexamethylene diisocyanate is added, and the reaction process is the same as in Preparation Example 6. Upon completion of this reaction, a prepolymer having a hydroxyl value of 31.2 mgKOH / g and an acid value of 14.4 mgKOH / g is formed. In order to make the present prepolymer into an aqueous dispersion, 12.7 parts by weight of dimethylethanolamine was added to the present prepolymer over 15 minutes, and the reaction was carried out for 15 minutes. Thereafter, the neutralized prepolymer is added to a container containing 865.5 parts by weight of distilled water at 40 ° C., and then the neutralized prepolymer is added to a container containing 865.5 parts by weight of distilled water at 40 ° C., and the procedure is the same as in Preparation Example 6. Thus obtained water-dispersed polyester polyol has a solid content of 42.0% by weight, a final acid value of 2.9mgKOH / g, a hydroxyl value of 37.2mgKOH / g, pH 7.4, the viscosity is a bubble viscometer N, the particle size is 70 nanometers, surface tension 61.0dyne / cm It is a stable water dispersible resin.

Preparation Example 10

640.0 parts by weight of polyester polyol of Preparation Example 4, 30.0 parts by weight of polyethylene glycol, 30.0 parts by weight of dimethylol propionic acid, 89.5 parts by weight of N-methyl-2-pyrrolidone and 0.8 weight of dibutyl tin dilaurate in the newly installed reactor The part was introduced under nitrogen injection and stirred in the same manner as in Preparation Example 6. When the reactants are homogeneously mixed, the mixture is cooled to 70 ° C., 300.8 parts by weight of acetone is added, and 52.0 parts by weight of hexamethylene diisocyanate is added. The reaction process is the same as in Preparation Example 6. Upon completion of this reaction, a prepolymer having a hydroxyl value of 46.3 mgKOH / g and an acid value of 16.7 mgKOH / g is formed. In order to make the prepolymer into an aqueous dispersion, 18.0 parts by weight of dimethylethanolamine was added to the prepolymer over 15 minutes and maintained for 15 minutes. Thereafter, the neutralized prepolymer was added to 931.0 parts by weight of distilled water at 40 ° C., and the procedure was the same as in Preparation Example 6. The water-dispersed polyurethane polyester polyol thus obtained had a solid content of 42.0 wt%, a final acid value of 1.7 mgKOH / g, a hydroxyl value of 46.3 mgKOH / g, a pH of 7.7, a viscosity of 0 with a bubble viscosity meter, a particle size of 65 nanometers, and a surface tension of 63.0 dyne /. It is a stable water dispersion resin which is cm.

Preparation Example 11

Into the newly installed reactor, 670.0 parts by weight of polyester polyol of Preparation Example 5, 67.0 parts by weight of trimethylolpropane, 201.0 parts by weight of dimethylol propionic acid, and 135.0 parts by weight of N-methyl-2-pyrrolidone were charged under nitrogen injection. Stirring in the same manner as in Preparation Example 6. When the reactants are homogeneously mixed, 840.7 parts by weight of hexamethylene diisocyanate is added over 1 hour while maintaining the reaction temperature at 70-80 ° C. and the reaction is continued at 80 ° C. for at least 3 hours. Then, when the isocyanate content reaches 5.4% by weight, when 303.7 parts by weight of butanone oxime is added dropwise, an exothermic phenomenon occurs in which the temperature rises to 110 to 120 ° C. After all the exotherm has been removed, the reaction is continued for at least 2 hours while maintaining the temperature at 120 ° C., and the end point of the reaction is taken at the point where the isocyanate content becomes zero. At the end of the reaction, a prepolymer having an acid value of 40.4 mgKOH / g is formed. In order to neutralize this prepolymer, the temperature was lowered below 90 ° C., 131.0 parts by weight of dimethylethanolamine was added over 30 minutes, and maintained for 30 minutes. Thereafter, heated to 90 ° C., 2494.0 parts by weight of distilled water was added to the prepolymer maintained at 300 rpm over 1 hour, and maintained for 1 hour or more. The stable water-soluble block polyisocyanate resin had a solid content of 40.0 wt% and a final acid value of 1.0 mg KOH / g, The pH is 8.7, the viscosity is a bubble viscometer, Z, the particle size is a stable water-soluble resin of 40 nanometers or less.

Preparation Example 12

670.0 parts by weight of the polyester polyol of Preparation Example 5, 67.0 parts by weight of trimethylolpropane, 201.0 parts by weight of dimethylol propionic acid, and 135.0 parts by weight of N-methyl-2-pyrrolidone were introduced into a newly installed reactor under nitrogen injection. The temperature is raised to 100 ° C. so that the components are homogeneously mixed. When the components are homogeneously mixed and transparent, 840.7 parts by weight of hexamethylene diisocyanate is added dropwise over 30 minutes while maintaining the temperature at 50 ° C. and the reaction is continued while maintaining 60 ° C. for 4 hours or more. Then, when the isocyanate content reaches 9.21% by weight, when 376.0 parts by weight of 3,5-dimethylpyrazole is added dropwise, an exothermic phenomenon occurs in which the temperature rises to 80 to 90 ° C. After all the exotherm is removed, the reaction is maintained at 80 ° C. for at least 2 hours, and the end point of the reaction is taken at the point where the isocyanate content becomes zero. Upon completion of this reaction, a prepolymer having an acid value of 39.0 mgKOH / g is formed. To neutralize the prepolymer, 131.0 parts by weight of dimethylethanolamine was added over 30 minutes and held for 30 minutes. Thereafter, 2966 parts by weight of distilled water heated to 80 ° C. was added to the present prepolymer maintained at 300 rpm over 1 hour, and maintained for 1 hour or longer to form a stable water-dispersible block polyisocyanate resin. This water-dispersed blocked polyisocyanate resin is a stable water-dispersed resin having a solid content of 40.0% by weight, a final acid value of 1.0 mgKOH / g, a pH of 7.5, a viscosity of D in a bubble viscometer, and a particle size of 180 nanometers.

Preparation Example 13

840.0 parts by weight of the polyester polyol of Preparation Example 5, 67.0 parts by weight of trimethylolpropane, 201.0 parts by weight of dimethylolpropionic acid, and 350.0 parts by weight of N-methyl-2-pyrrolidone were added to a newly installed reactor under nitrogen injection. Proceed in the same manner as in Production Example 11. When the reactants are homogeneously mixed and in a transparent state, 1110.0 parts by weight of isophorone diisocyanate is added while maintaining the temperature at 50 ° C. to carry out the reaction in the same manner as in Preparation Example 11. Then, when the isocyanate content reaches 6.63% by weight, 336.5 parts by weight of 3,5dimethylpyrazole is added dropwise, and the reaction is carried out in the same manner as in Preparation Example 11, and when the reaction is completed, an acid value of 32.9 mgKOH / g is formed. do. To neutralize the present prepolymer, 120.2 parts by weight of dimethylolamine is added over 30 minutes and held for 30 minutes. Thereafter, 3361.8 parts by weight of distilled water heated to 80 ° C. was added to the prepolymer over 1 hour, and maintained for 1 hour or longer to form a stable water-dispersible block polyisocyanate resin. The water-dispersible block polyisocyanate resin is a stable water dispersion resin having a solid content of 40.0% by weight, a final acid value of 3.3 mgKOH / g, a pH of 7.2, a viscosity of C with a bubble viscometer, and a particle size of 210 nanometers.

Production Examples 6, 7, 8, which are water-dispersed polyurethane polyester polyol resins for improving hardness, and Production Examples 9 and 10, which are water-dispersed polyurethane polyester polyol resins for softening, are prepared in the range of 2: 1 to 4: 1 and 12, which are the main resins and the water-dispersible block polyisocyanate resins of the curable resin, are combined at 50:50 to 85:25 by the solid content, that is, the water-dispersed polyurethane polyester polyols. Optimal dispersion of paints when additives, co-solvents, pigments and extender pigments are added to the resin compositions of the present invention in which the equivalent ratio of the hydroxyl groups of the resins and the isocyanate groups of the water-dispersed blocked polyisocyanate resin is 1: 1.4 to 1: 0.75. It can maintain the state and improve the water resistance, chemical resistance and mechanical properties of the cured coating film, especially yellowing phenomenon and impact property of the cured coating film even under baking conditions at low temperature (130 ~ 150 ℃). It can be the water dispersed resin composition and a water-soluble coating composition.

Application experiments according to the composition change of the coating using the water-dispersible resin prepared by the above was performed as follows. Hereinafter, the fluidity regulators used in Examples 1 to 5 below were Viscalex HV-30 (AlliedColloid) and Bermodol PUR2100 (Langer), and a melt silica type thickener was used as Aerosil R-972 (Degussa), and the dispersant was Disperbyk (-). 190 (BYK-Chemie), antifoaming agent BYK-022 (BYK-Chemie), and smoothing agent BYK-345 (BYK-Chemie).

Example 1

The compositions of 1 to 11 were added in the order described in Example 1, premixed for 20 minutes, and then 0.8 times to 1.0 times the glass beads of the same weight were added to completely seal the disperser. After dispersing for 1 to 2 hours of use, 12 to 17 compositions are added and completely dispersed with a general disperser, 18 compositions are added to adjust the pH of the entire coating composition to 8 to 9. In the case of applying the water-soluble coating composition prepared in this way, the water-soluble coating composition is sprayed or bell-coated to 30 to 45 microns with a dry coating film on the electrodeposition-treated coating, and the setting time is maintained at room temperature for 5 minutes, and then the oven oven is Flash-off was performed at 80 degreeC for 5 minutes, and the method of heat-hardening with 130-150 for 20 to 30 minutes was adopted in the convection oven, and the water-soluble coating composition was produced.

Example 2

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Example 2 were used.

Example 3

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Example 3 were used.

Example 4

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Example 4 were used.

Comparative Example 1

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Comparative Example 1 were used.

Comparative Example 2

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Comparative Example 2 were used.

Comparative Example 3

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Comparative Example 3 were used.

Comparative Example 4

A water-soluble coating composition was prepared in the same manner as in Example 1, except that parts by weight of the compositions 1 to 18 described in Comparative Example 4 were used.

TABLE 1 Paint and Coating Properties

* Condition in container: No dust, foreign matter, hard lump and dispersed evenly

* Spray / Bell workability: Atomization state of paint and smooth cleaning of painting equipment during painting

Particle size: After mill-base, the particle size should be 20 micron or less

Paint storage: It should be within 15% of viscosity change rate at room temperature (25 ℃) and more than 3 months

* Understandability: Less than two crater rings on 3,000 × 20 mm specimen

* Gloss: 60 or more at 60 °

* Pencil hardness: should be over HB

* Adhesion: Cross-cut, at least 100/90 at 1mm interval

* Impact resistance: When it is dropped at 500g weight and 20cm height, there is no crack or peeling.

* Cold resistance chipping resistance: -40 ℃ x 3 hours, chipping test results, 1 ~ 2mm 15 or less / 2mm or more 2 or less

* Water resistance: No change of color and gloss and good adhesion

* Abrasion resistance: When polishing with 600 Cw abrasive paper, particles should be evenly spread out

* Oil resistance: No change of color and gloss after 1 hour immersion

* Acid resistance: 10% sulfuric acid solution, no spot on the coating after spot test for 70 ℃ x 30 minutes

* Base resistance: 10% sodium hydroxide solution, 70 ℃ x 30 minutes after spot test, no phenomenon

* Yellowing degree: △ Y value should be 0.3 or less when measuring yellowing phenomenon of coating after recuring at 170 ℃ x 1 hour

Claims (8)

As the main balance, Polyethylene glycol containing polyethylene oxide is 0.3-10% in solid content, water-dispersed poly with acid value of 16-36mgKOH / g, hydroxyl value of 60-120mgKOH / g, weight average molecular weight 3000-6000 before neutralization by dimethylol propionic acid Polyurethane polyester polyol resin, polyethylene glycol 0.3 to 10% as a solid content, acid value before neutralization by dimethylol propionic acid 13-24 mgKOH / g, hydroxyl value 30-60 mgKOH / g, the weight average molecular weight 10000-25000 The dispersed polyurethane polyester polyol resin is mixed in a solid ratio of 2: 1-4: 1, As hardening resin, A water-dispersed blocked polyisocyanate having an acid value of 25-50 mgKOH / g before neutralization with dimethylol propionic acid, a content of blocked isocyanate (-NCO) of 4-15% by weight, and a weight average molecular weight of 1500-5000 was prepared. The equivalent ratio of the hydroxyl group of the main resin and the isocyanate group of the cured resin is 1: 1,4-1: 0.75, and the solid content ratio is 50: 50-85: 25, The water-dispersible blocked polyisocyanate resin reacts a polyhydric alcohol with a polyvalent acid to synthesize a polyester polyol, and then homogeneously mixes anionic groups, polyvalent alcohols and a co-solvent, and adds a polyvalent isocyanate to the remaining isocyanate. When the content is 4 to 16% by weight of the polyurethane prepolymer solid content is prepared by blocking by adding a blocking agent, neutralizing by adding a neutralizing agent, The blocking agent uses 3,5-dimethylpyrazole, 3-methylpyrazole, 4-nitro-3,5-dimethylpyrazole or 4-bromo-3,5-dimethylpyrazole, and the total water dispersion block Water-dispersible resin compositions, characterized in that added at 4-12% by weight relative to the resin composition. A low temperature curing and non-yellowing water-soluble coating composition composed of the composition of claim 1, a flow control agent, a melt silica type thickener, a dispersant, an antifoaming agent, a leveling agent, a coarse agent, a pigment, and a sieving pigment. The flow control agent as the additive is a polyacrylic emulsion type and a polyurethane type thickener are used in combination in a ratio of 2: 1 to 5: 1 in solid content ratio, and 1: 1 to 4.5 in fused silica type thickener and solid content ratio. It is characterized in that the addition of 1.0 to 3.0% by weight based on the total water-soluble coating composition, the fused silica type thickener is added to the mill-base, and the fluidity regulator is post-added low temperature curing and non-yellowing water-soluble coating Composition. The low temperature hardening and non-yellowing water-soluble coating composition according to claim 2, wherein the dispersing agent is a nonionic acid dispersant suitable for an inorganic pigment system and is added at 0.5-1.5 wt% based on the total water-soluble paint compositions. The antifoaming agent according to claim 2, wherein the antifoaming agent is a polysiloxane antifoaming agent and is added at 0.05-0.5% by weight based on the total water-soluble coating composition. The low-temperature hardening and non-yellowing water-soluble coating composition according to claim 2, wherein the leveling agent is a polysiloxane antifoaming agent and is added at 0.1-1.0 wt% based on the total water-soluble coating composition. The low temperature curing and non-yellowing water-soluble coating composition according to claim 2, wherein the co-solvent is used in combination of butyl glycol and butyl carbitol and added at 4 to 9% by weight based on the total water-soluble coating composition. According to claim 2, The pigment is an inorganic coloring pigment such as titanium dioxide, carbon black, and sieving pigments such as barium sulfate, magnesium silicate, 15-30% by weight based on the total water-soluble coating composition, Low-temperature curing and non-yellowing water-soluble coating composition, characterized in that the weight ratio of barium sulfate and magnesium silicate of the extender pigment is 1: 1-3: 1, and the extender pigment is added 5-15% by weight based on the total water-soluble paint composition.