RU2415878C1 - Composition for producing coatings via cathodic electrodeposition, having improved curing behaviour and corrosion resistance - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: composition contains 20-70 pts. wt polymer cross-linking agent which contains a product of a reaction between a polyol compound, obtained from glycidyl ether and amine, and a derivative of a polyisocyanate compound whose functional groups are blocked, 30-80 pts. wt main resin and 0.1-10 pts. wt polymer curing agent which contains a metal, wherein the polyol compound, obtained from glycidyl ether and amine, is a product of a Mannich reaction between a derivative of a phenol compound, a derivative of an amine compound and formalin. ^ EFFECT: obtaining a polymer composition which exhibits high corrosion resistance and curing behaviour when applied, using conventional installations. ^ 20 cl, 9 tbl

Description

FIELD OF THE INVENTION

The present invention relates to a polymer composition for producing coatings by cationic electrodeposition, which comprises from 20 to 70 parts by weight of a polymer crosslinking agent containing a reaction product of a polyol compound derived from glycidyl ether and an amine with a derivative compound of a polyisocyanate in which functional groups are blocked; 30 to 80 parts by weight of base resin; and from 0.1 to 10 parts by weight of a polymer curing catalyst containing a metal, wherein the polyol compound obtained from glycidyl ether and an amine is the reaction product of a phenol derivative, an amine derivative and formalin derivative by the Mannich reaction.

State of the art

Electrodeposition paints were developed in the 1970s; they were used as anti-corrosion paints at various enterprises associated with the automotive industry, and due to their effectiveness, continuity of coating and environmental safety, they were widely used for coating various parts, as well as on car bodies. Resin intended for coating by electrodeposition, which is the main component of the applied electrodeposition of paint, is the most important ingredient that determines the properties of the paint as a whole. The electrodeposition coating resin generally includes a base resin and a polymeric crosslinking agent, and may also include a curing catalyst.

Epoxy resin is representative of the main resins used for cationic electrodeposition. As the polymer crosslinking agent, polyisocyanate with blocked functional groups is mainly used. In particular, conventional resins designed to produce cationic electrodeposition coatings are prepared by a process which comprises mixing epoxy resin containing 180 to 10,000 equivalents, in an amount of 10 to 90% of the solids content, with bisphenol-A and its derivatives or with a plasticizer, such as a modified polyester; the interaction of amine and diol at a temperature in the range from 70 to 170 ° C in the presence of an excess of solvent; removing the organic solvent contained in the reaction mixture in vacuo at high temperature; mixing the polymer crosslinking agent with the mixture obtained after removal of the solvent; neutralizing the resulting mixture with a sufficient amount of organic acid, such as formic acid, lactic acid or acetic acid; and dispersing the resulting mixture in water for 4-12 hours by adding deionized water.

Japanese Patent Laid-open Applications No. H4-91170 and H5-155980 (KANSAI) use a polyamide resin as the main resin in order to enhance corrosion resistance and curing ability, however, problems such as poor appearance and loss of elasticity since the polyamide resin increases the degree of crosslinking during the formation of the coating layer. To solve this problem, a plasticizer is additionally added, however, the plasticizer causes another problem, which is associated with a deterioration in resistance to water and corrosion.

Japanese Patent Application Laid-open No. H2-219870 (KANSAI) describes the use of lead oxide in order to improve the adhesive properties, degree of crosslinking, and cure rate of such conventional resins intended to produce cationic electrodeposition coatings. However, the inclusion of lead in the composition is contrary to the international trend to limit the use of heavy metals.

SUMMARY OF THE INVENTION

The authors of the present invention have developed a polymer composition for producing coatings by cationic electrodeposition, which, in order to accelerate curing, contains the product of the interaction of a polyol as one compound obtained from glycidyl ether and an amine with a derivative of a polyisocyanate which has functional groups blocked as a crosslinking component; and barium as a curing catalyst to accelerate curing. The polymer composition intended for cationic electrodeposition deposition according to the present invention can be obtained in conventional production plants rather than in specially designed production plants, and the corrosion resistance and curing ability of the composition can be improved while maintaining the same level as compared with conventional compositions, appearance and elasticity.

Thus, the present invention provides highly functional polymer compositions for cationic electrodeposition deposition, which have improved corrosion resistance and curing ability.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a polymer composition for coating by cationic electrodeposition, which comprises from 20 to 70 parts by weight of a polymeric crosslinking agent containing a reaction product of a polyol compound derived from glycidyl ether and an amine with a derivative compound of a polyisocyanate in which functional groups are blocked; 30 to 80 parts by weight of base resin; and from 0.1 to 10 parts by weight of a polymer curing catalyst containing a metal, wherein the polyol compound obtained from glycidyl ether and amine is the product of the reaction of a phenol derivative, an amine derivative and formalin derivative by the Mannich reaction.

Further, the present invention is described in more detail.

Polymeric Crosslinking Agent

Resins intended for electrodeposition coatings generally include a base resin and a polymeric crosslinking agent, and may also include a curing catalyst. The polymer crosslinking agent reacts with the base resin and forms a final coating layer. In particular, the isocyanate groups contained in the polymer crosslinking agent react with the hydroxyl groups contained in the base resin at a given temperature or higher temperature to form a stable coating layer. In a composition in which a polymer crosslinking agent and a base resin are mixed, in order to prevent the reaction of the isocyanate group in the polymer crosslinking agent and the hydroxyl group in the base resin at a lower temperature than a predetermined temperature, a polymer crosslinking agent is used in which the functional group system is blocked, so that the coating layer is formed when interacting with the desired component in the main resin by the type of urethane reaction at a temperature higher than the specified temperature, while ensuring vayutsya properties such as good curability, corrosion resistance, water resistance, etc.

The polymer crosslinking agent that is used in the present invention contains the reaction product of a polyol as one compound obtained from glycidyl ether and an amine with a derivative of a polyisocyanate in which functional groups are blocked; 30 to 80 parts by weight of base resin; and a polyol compound obtained from glycidyl ether and amine is synthesized from a phenol derivative, an amine derivative and formalin derivative by the Mannich reaction.

The Mannich reaction is the interaction of a compound containing an aldehyde group, a derivative of a compound of a primary or secondary amine and a derivative of a phenol compound. As is well known, a composition having an active hydrogen atom in an amine compound through the Mannich reaction is widely used as a low-temperature crosslinking agent to produce conventional epoxy paints. It is known that if a Mannich reaction product having an active hydrogen atom in an amine compound is added to an epoxy crosslinking agent, then good curing ability is achieved at room temperature and at a lower temperature. In the present invention, in contrast to the conventional Mannich reaction products used in conventional epoxy paints, a Mannich-modified compound of the polyol type is synthesized from glycidyl ether and an amine and contains a reactive hydroxyl group, which is obtained by removing the active hydrogen atom of the amine derivative from the product Mannich reaction and carrying out an additional reaction after the completion of the Mannich reaction, and thus it can have a different structure and can find different application. In accordance with the present invention, a polyol compound obtained from glycidyl ether and amine is added to the polymer crosslinking agent in a resin for electrodeposition coating and a urethane-type reaction with an isocyanate group is initiated so as to obtain a coating having good curing ability . As a result, the present invention can improve corrosion resistance.

The phenol derivative that is used in the Mannich reaction may be selected, but not limited to, from the group consisting of cresol, butylphenol, octylphenol, nonylphenol and phenol, preferably it may be selected from the group consisting of octylphenol, nonylphenol and phenol, and more preferably may be selected from the group consisting of nonylphenol and phenol. The phenol derivative may be used individually or as a mixture of two compounds selected from the above group. The amine derivative used in the Mannich reaction is preferably an aliphatic or aromatic amine derivative, more preferably a compound selected from the group consisting of ethylenediamine, trimethylenediamine, hexamethylene diamine, octamethylene diamine, diethylenetriamine, triethylenetetamine, tetraethylene pentamine di-methamine. An amine derivative can be used individually or as a mixture of two or more compounds selected from the above group.

The amount of the phenol derivative used in the Mannich reaction is 20-50 wt.%, Preferably 25-45 wt.% And more preferably 30-40 wt.%, Of the amount of the Mannich reaction product. If the amount of the phenol derivative compound is less than 20 wt.%, The corrosion resistance may be reduced. If the amount of the phenol compound derivative is greater than 50 wt.%, Then the viscosity and degree of curing may increase excessively. The amount of the amine derivative used in the Mannich reaction is 20-50 wt.%, Preferably 25-45 wt.% And more preferably 30-40 wt.%, Of the amount of the Mannich reaction product. If the amount of the derivative of the amine compound is less than 20 wt.%, Then the unreacted compound remains in the reaction product and thus it may not be possible to achieve sufficient hiding power. If the amount of the derivative of the amine compound is greater than 50 wt.%, Urea functional groups are formed, so that insoluble particles can form during the reaction or after the reaction. The amount of formalin used in the Mannich reaction is 15-45 wt.%, Preferably 20-40 wt.% And more preferably 25-35 wt.%, Of the amount of the product of the Mannich reaction. If the amount of formalin is less than 15 wt.%, Unreacted amine can form in large quantities. If the amount of formalin is more than 45 wt.%, Then there is a risk of gelation, since the viscosity may increase excessively.

Depending on the derivative of the phenol compound and the derivative of the amine compound, various types of Mannich reaction products can be obtained. Preferred Mannich reaction products, however, are not limited to the structure corresponding to the following formula 1.

Formula 1

wherein each R is independently a phenol derivative, preferably cresol, butylphenol, octylphenol, nonylphenol or phenol.

The polyol compound obtained from glycidyl ether and amine, which is used in the polymer crosslinking agent, is mainly the product of the Mannich reaction of the hydroxyl-containing derivative of the amine compound and the derivative of the glycidyl ether compound. The hydroxyl-containing derivative of the amine compound is preferably a hydroxyl-containing derivative of an aliphatic or aromatic amine, more preferably it is a compound selected from the group consisting of monoethanolamine, diethanolamine, monoisopropanolamine, di-isopropanolamine, monoethylethanolamine and monomethylethanolamine, and more preferably, it is also a compound, and a group that includes ethyl ethanolamine and methylethanolamine. The glycidyl ether derivative is selected from the group consisting of phenyl glycidyl ether and butyl glycidyl ether.

The amount of the hydroxyl-containing derivative of the amine compound is from 8 to 30 parts by weight, preferably from 11 to 27 parts by weight, and even more preferably from 14 to 24 parts by weight, per 100 parts by weight of the total weight of the solid Mannich reaction products. If the amount of the hydroxyl-containing derivative of the amine compound is less than 8 parts by weight, the number of reactive terminal hydroxyl groups is insufficient and, thus, the curing reaction involving isocyanate groups does not proceed to the end. If the amount of the hydroxyl-containing derivative of the amine compound is more than 30 parts by weight, then the stability of the reaction product may decrease. The amount of the glycidyl ether derivative compound is from 40 to 70 parts by weight, preferably from 44 to 64 parts by weight, and even more preferably from 48 to 60 parts by weight, per 100 parts by weight of the total weight of the solid Mannich reaction products.

Preferred polyol as one compounds obtained from glycidyl ether and amine in the form of the Mannich reaction product, which are suitable for use in the present invention, have the structure, but not limited to, which is represented by formula 2.

Formula 2

where each R ₁ independently represents a phenol derivative, preferably cresol, butylphenol, octylphenol, nonylphenol or phenol; each R ₂ independently represents a derivative of glycidyl ether, preferably butyl glycidyl ether or phenyl glycidyl ether; and R ₃ is a hydroxyl-containing derivative of an amine compound, preferably monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine, monoethylethanolamine or monomethylethanolamine.

The amount of polyol as one compound obtained from glycidyl ether and amine used in the polymer crosslinking agent of the present invention is from 1 to 20 wt.%, Preferably from 1 to 10 wt.% And more preferably from 1 to 5 wt.%, From the total mass of the polymer crosslinking agent. If the amount of the polyol as one compound obtained from glycidyl ether and amine is less than 1 wt.%, The effect of improving the curing ability is insufficient. If the amount of the polyol as one compound obtained from glycidyl ether and amine is more than 20 wt.%, The appearance may deteriorate due to an increase in viscosity and high speed of the initial curing step.

Functionally blocked polyisocyanate that is capable of reacting with a Mannich reaction product containing a polyol compound derived from glycidyl ether and an amine, the present invention can be easily selected from those polyisocyanates that are known to be suitable for use in a polymer coating composition cationic electrodeposition method. A polyisocyanate in which functional groups are blocked, mainly, but not limited to, is the product of the interaction of a derivative of a diisocyanate compound and a hydroxyl-containing acrylate derivative or derivative of an alcohol compound. The amount of polyisocyanate with blocked functional groups is from 80 to 99 wt.%, Preferably from 90 to 99 wt.% And more preferably is from 95 to 99 wt.%, Based on the amount of polymer crosslinking agent. If the amount of polyisocyanate with blocked functional groups is less than 80 wt.%, The problem of incomplete curing may occur. If the amount of polyisocyanate with blocked functional groups is more than 99 wt.%, Then curing proceeds faster, but corrosion resistance may decrease.

The diisocyanate derivative compound is advantageously an aliphatic or aromatic diisocyanate derivative and more preferably is selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-methylene bis (phenyl diisocyanate), tetramethylene diisocyanate and hexamethylene diisocyanate. The hydroxyl-containing acrylate derivative is preferably 2-hydroxyethyl methacrylate. The alcohol derivative is preferably selected from the group consisting of ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, trimethylol propane and propylene glycol.

The amount of polymer crosslinking agent that is used in the polymer composition for producing cationic electrodeposition coatings of the present invention is from 20 to 70 parts by weight, preferably 25 to 50 parts by weight, and more preferably 30 to 40 parts by weight. If the amount of polymer crosslinking agent is less than 20 parts by weight, then the curing temperature rises and the corrosion resistance decreases due to incomplete curing. If the amount of the polymeric crosslinking agent is more than 70 parts by weight, the appearance deteriorates due to the high density during curing, and the corrosion resistance decreases due to the absence of an epoxy ingredient in the base material.

Base resin

The base polymer for a resin for cationic electrodeposition deposition is a component that, together with a polymer crosslinking agent, forms a final coating layer. The properties of the final coating layer are determined by the chemical and physical properties of the base resin. The epoxy compound is most widely used as the main component of the base resin, because it provides the final coating layer with good corrosion resistance, adhesive properties and heat resistance. To obtain a resin intended for cationic electrodeposition coating, an epoxy compound is reacted with an amine derivative to form hydroxyl groups which are necessary for the reaction with dissociated isocyanate groups of a crosslinking agent during coating formation. Epoxy compounds in particular have good corrosion resistance, and therefore are most often used in coating materials for which corrosion resistance is required. The molecular weight of the epoxy compound used as the base resin is from 180 to 2000. The epoxy compound can be selected from epoxy compounds that contain one or two epoxy groups and can be used individually or in combination. In addition, the molecular weight can be increased to the desired level by further reaction with bisphenol-A. The primary amine derivative compounds used are primary or secondary aliphatic, aromatic or alicyclic amines. An aliphatic, aromatic or alicyclic amine that has one or more active hydrogen atoms or contains one or two hydroxyl groups can be used to improve the curing ability. The amount of the epoxy compound can be from 60 to 90 wt.%, And the amount of the derivative of the amine compound can be from 10 to 40 wt.% Of the total weight of the base resin, but this is not limited to.

The amount of the base resin used in the cationic electrodeposition coating polymer composition of the present invention is from 30 to 80 parts by weight, preferably from 50 to 75 parts by weight, and more preferably from 60 to 70 parts by weight. If the amount of the base resin is less than 30 parts by weight, the appearance (or smoothness), elasticity and corrosion resistance are degraded. If the amount of the base resin is more than 80 parts by weight, then the curing ability becomes problematic.

Polymer Curing Catalyst

Although in the general case, the electrodeposition coating polymer compositions optionally include a curing catalyst, the electrodeposition coating polymer composition of the present invention separately includes a polymer curing catalyst that comprises a curing catalyst. It is known that if the metal used as a curing catalyst is independently added to the resin used to produce coatings by cationic electrodeposition, then the properties of the resin used to obtain coatings by cationic electrodeposition, such as reaction stability, storage stability, and the ability to filtering, etc. A similar problem is reducing the stability of the reaction, storage stability, filtration ability, etc. can be solved by separately preparing a polymer curing catalyst containing a metal salt or a metal chelate as a curing catalyst, and adding it to the resin used to form the coatings by cationic electrodeposition. The function of the curing catalyst is to accelerate the interaction of hydroxyl groups in the base resin and isocyanate groups in the polymer crosslinking agent. The curing catalyst can be selected so that the reaction temperature can be reduced.

In order to control the cure rate, the cationic electrodeposition coating polymer composition of the present invention includes a metal curing polymer curing catalyst. The metal used in the polymer curing catalyst can be selected from the group consisting of zirconium, zinc, calcium, lead, tin, bismuth, cobalt, titanium, aluminum, chromium and barium, and the metal may be present in the form of a salt or in the form of a chelate. More preferably, the metal salt or metal chelate is barium hydroxide, barium salt of phenol or barium chelate with phenol. Even more preferably, the metal-containing polymer curing catalyst comprises a barium salt of phenol or barium chelate with phenol.

The amount of metal used in the polymer curing catalyst is from 1 to 20 wt.%, Preferably from 3 to 15 wt.%, And more preferably is from 5 to 10 wt.%, Based on the amount of the polymer curing catalyst. If the amount of metal is less than 1 wt.%, Then the ability to cure is insufficient. If the amount of metal is more than 20 wt.%, Then the curing rate becomes too high, and the appearance is deteriorated.

The amount of metal-containing polymer curing catalyst used in the polymer composition for producing cationic electrodeposition coatings of the present invention is from 0.1 to 10 parts by weight, preferably from 0.1 to 7 parts by weight, and more preferably from 0.1 to 5 weight parts. If the amount of metal-containing polymer curing catalyst is less than 0.1 parts by weight, then the temperature required for the interaction of hydroxyl groups in the base resin and isocyanate groups in the polymer crosslinking agent increases, which leads to an increase in cost due to additional energy costs. If the amount of metal is more than 10 parts by weight, then the content of the curing catalyst becomes greater than the corresponding amount required for the reaction, and thus, there may be a problem of storage stability due to an increase in the amount of precipitate of the curing catalyst released during storage of the resin used to obtain coatings by electrodeposition.

The present invention is explained in more detail using the following examples and comparative examples. However, the following examples only illustrate the present invention, and should not be construed as limiting the scope of the present invention.

Example 1

The polyol compound obtained from glycidyl ether and amine, which is isolated from the Mannich reaction product of the present invention, is synthesized from the components shown in table 1, in accordance with the method described below.

Table 1 Components for the synthesis of a polyol as one compound derived from glycidyl ether and amine Component amount (A) Nonylphenol 184.9 g (B) Metaxyldiamine 192.1 g (C) Formalin 151.0 g (D) Extracted water -125.0 g (E) Methylethanolamine 76.9 g (F) Butyl glycidyl ether 220.1 g (G) Methoxypropanol 300.0 g Total amount 1000.0 g

In a three-necked flask with a capacity of 2 l, equipped with a thermometer, a refrigerator and a mechanical stirrer, in accordance with table 1, nonylphenol (A) and methaxyldiamine (B) are placed and the temperature is raised to 70 ° C. Formalin (C) was slowly added to the resulting mixture over an hour, and then the temperature was maintained at 95 ° C for 2 hours. They increase the temperature to 125 ° C and release water formed by the dehydration reaction. When the amount of extracted water (D) is 125 g, the reaction mixture is cooled to 90 ° C. Methylethanolamine (E) and butyl glycidyl ether (F) were added to the mixture, and the reaction mixture was stirred for 2 hours. The temperature was raised to 125 ° C and unreacted diamine was isolated over 30 minutes. The reaction mixture was cooled to 110 ° C and diluted with methoxypropanol (G) to stop the reaction. The reaction is carried out carefully, since the reaction mixture easily boils during the reaction. If the ratio of recovered diamine is insufficient, then the unreacted diamine can be recovered at high temperature in vacuo. In the product obtained as described above, the solids content is 70%.

Example 2

The polymer crosslinking agent of the present invention is obtained from the components shown in table 2, in accordance with the method, which is explained below.

table 2 Components for the preparation of the polymer crosslinking agent of the present invention Component amount (A) 4,4'-Methylene bis (phenyl diisocyanate) 446.0 g (B) Methylisobutylketone 22.1 g (C) 2-Hydroxyethanol methacrylate 331.0 g (D) Trimethylolpropane 59.8 g (E) The reaction product of example 1 16.6 g (F) Methoxypropanol 124.5 g Total amount 1000.0 g

In a three-necked flask with a capacity of 2 l, equipped with a thermometer, a refrigerator and a mechanical stirrer, in accordance with table 2, phenyl diisocyanate (A) and methyl isobutyl ketone (B) are placed and the temperature is increased to 40 ° C. While supplying air, 2-hydroxyethanol methacrylate (C) was slowly added dropwise over 2 hours, controlling the isocyanate content, and when the isocyanate content was from 5.0 to 5.5%, trimethylolpropane (D) was added to the reactor and the reaction product of Example 1 (E). The temperature was raised to 80 ° C. and maintained for 30 minutes by controlling the isocyanate content, and when the isocyanate content was 0.2% or less, the reaction was stopped. Upon completion of the reaction, allow the reaction mixture to cool to a temperature of 80 ° C or lower and dilute with methoxypropanol (F) to complete the process. During the reaction, the temperature of the reaction mixture is carefully monitored to 85 ° C or less. The solids content in the obtained resin is 85%.

Example 3

A conventional polymeric crosslinking agent is obtained from the components shown in table 3, in accordance with the method, which is described below.

Table 3 Components for the preparation of a conventional polymeric crosslinking agent Component amount (A) 4,4'-Methylene bis (phenyl diisocyanate) 484.7 g (B) Methylisobutylketone 24.2 g (C) Butyl cellosolve 288.9 g (D) Trimethylolpropane 74.5 g (E) Methoxypropanol 127.7 g Total amount 1000.0 g

In a three-necked flask with a capacity of 2 l, equipped with a thermometer, a refrigerator and a mechanical stirrer, in accordance with table 3, phenyl diisocyanate (A) and methyl isobutyl ketone (B) are placed and the temperature is increased to 45 ° C. Butyl cellosolve (C) was slowly added dropwise over 2 hours, monitoring the isocyanate content, and when the isocyanate content was from 5.0 to 5.5%, trimethylolpropane (D) was added to the reactor. The temperature was raised to 80 ° C. and maintained for 30 minutes by controlling the isocyanate content, and when the isocyanate content was 0.2% or less, the reaction was stopped. At the end of the reaction, allow the reaction mixture to cool to a temperature of 80 ° C or less and dilute with methoxypropanol (F) to complete the process. The solids content in the obtained resin is 85%.

Example 4

The polymer containing the barium salt of phenol of the present invention is obtained from the components shown in table 4, in accordance with the method, which is explained below.

Table 4 Components for the production of a polymer containing the barium salt of phenol of the present invention Component amount (A) Phenol 80.6 g (B) Deionized water 800.0 g (C) Barium hydroxide 80.6 g (D) Lactic acid 38.8 g Total amount 1000.0 g

In a three-necked flask with a capacity of 2 L, equipped with a thermometer, a refrigerator and a mechanical stirrer, in accordance with Table 4, phenol (A) and deionized water (B) are placed and stirred for 30 minutes. Barium hydroxide (C) is added, the temperature is slowly raised to 60 ° C and maintained for 4 hours, and then the reaction mixture is cooled to 30 ° C or less. Lactic acid (D) was added and stirred for 1 h, and then the reaction was quenched. The solids content in the obtained resin is 20%.

Example 5

The reaction product of a conventional base resin, a conventional polymeric crosslinking agent, and a polymer containing a phenol barium salt of the present invention is prepared from the components shown in Table 5 in accordance with the method described below.

Table 5 Components for the preparation of the reaction product Component amount (A) YD-128 ¹⁾ 525.1 g (B) PPG1000 ²⁾ 201.6 g (C) Bisphenol-A 104.3 g (D) Methoxypropanol 38.1 g (E) Diethanolamine 103.7 g (F) The reaction product of example 3 581.9 g (G) Formic acid 24.8 g (H) Deionized water 1637.6 g (I) The reaction product of example 4 72.8 g (J) Deionized Water 710.1 g Total amount 4000.0 g ¹⁾ Bisphenol-A type liquid epoxy resin (molecular weight: 380; Kukdo Chemical Co., Ltd.)
²⁾ Propylene glycol (molecular weight: 1000; Korea Polyol Co., Ltd.)

In a separation vessel with a capacity of 5 l, equipped with a mechanical stirrer, a refrigerator, a heater and a thermometer, in accordance with Table 5, YD-128 (A) and PPG1000 (B) are placed and the temperature is maintained at 140 ° C for 3 hours. Then, bisphenol-A is added. (C) and methoxypropanol (D) and maintain the temperature at 125 ° C for 2 hours. Then the reaction mixture is cooled to 110 ° C. At 110 ° C. diethanolamine (E) was added and the reaction mixture was stirred for 30 minutes, and then the reaction product of Example 3 (F) was added. After cooling the reaction mixture to 100 ° C or less, formic acid (G) and deionized water (H) are added and mixed. With further cooling of the reaction mixture, the reaction product of Example 4 (I) is added and deionized water (J) is added slowly over 3 hours to obtain a dispersion of the reaction mixture in water. During the dispersion step, the reaction mixture is cooled to 50 ° C or less, from time to time injecting cooling water, since prolonged exposure to temperatures above 50 ° C reduces the stability of the aqueous dispersion. At the end of the dispersion step, the mixture is purged with nitrogen for 10 minutes to remove air bubbles from the reaction mixture, and the reaction mixture is stirred for 2 hours. During the above process, since a large amount of heat is generated after the addition of the amine as an exothermic reaction, the temperature increase is controlled precisely for the purpose of controlling said spontaneous heat release. The solids content in the product obtained in accordance with the above methodology is 36%.

Example 6

The reaction product of a conventional base resin and a polymeric crosslinking agent of the present invention is obtained from the components shown in table 6, in accordance with the method, which is described below.

Table 6 Components for the preparation of the reaction product Component amount (A) YD-128 ¹⁾ 534.8 g (B) PPG1000 ²⁾ 205.4 g (C) Bisphenol-A 106.3 g (D) Methoxypropanol 38.8 g (E) Diethanolamine 105.7 g (F) The reaction product of example 2 592.7 g (G) Formic acid 25.2 g (H) Deionized water 1668.0 g (I) Deionized Water 723.1 g Total amount 4000.0 g ¹⁾ Bisphenol-A type liquid epoxy resin (molecular weight: 380; Kukdo Chemical Co., Ltd.)
²⁾ Propylene glycol (molecular weight: 1000; Korea Polyol Co., Ltd.)

In a separation vessel with a capacity of 5 l, equipped with a mechanical stirrer, a refrigerator, a heater and a thermometer, in accordance with Table 6, YD-128 (A) and PPG1000 (B) are placed and the temperature is maintained at 140 ° C for 3 hours. Then, bisphenol-A is added. (C) and methoxypropanol (D) and maintain the temperature at 125 ° C for 2 hours. Then the reaction mixture is cooled to 110 ° C. At 110 ° C. diethanolamine (E) was added and the reaction mixture was stirred for 30 minutes, and then the reaction product of Example 2 (F) was added. After cooling the reaction mixture to 100 ° C or less, formic acid (G) and deionized water (H) are added and mixed. With further cooling of the reaction mixture over 3 hours, deionized water (I) was slowly added to obtain a dispersion of the reaction mixture in water. During the dispersion step, the reaction mixture is cooled to 50 ° C or less, from time to time injecting cooling water, since prolonged exposure to temperatures above 50 ° C reduces the stability of the aqueous dispersion. At the end of the dispersion step, the mixture is purged with nitrogen for 10 minutes to remove air bubbles from the reaction mixture, and the reaction mixture is stirred for 2 hours. During the above process, since a large amount of heat is generated after the addition of the amine as an exothermic reaction, the temperature increase is controlled precisely for the purpose of controlling said spontaneous heat release. The solids content in the product obtained in accordance with the above methodology is 36%.

Example 7

The reaction product of a conventional base resin and a polymeric crosslinking agent, as well as a polymer of the present invention containing barium salt of phenol, is obtained from the components shown in table 7, in accordance with the method described below.

Table 7 Components for the preparation of the reaction product Component amount (A) YD-128 ¹⁾ 521.1 g (B) PPG1000 ²⁾ 203.6 g (C) Bisphenol-A 106.3 g (D) Methoxypropanol 39.1 g (E) Diethanolamine 101.5 g (F) The reaction product of example 2 584.2 g (G) Formic acid 24.8 g (H) Deionized water 1635.9 g (I) The reaction product of example 4 71.4 g (J) Deionized Water 712.1 g Total amount 4000.0 g ¹⁾ Bisphenol-A type liquid epoxy resin (molecular weight: 380; Kukdo Chemical Co., Ltd.)
²⁾ Propylene glycol (molecular weight: 1000; Korea Polyol Co., Ltd.)

In a separation vessel with a capacity of 5 l, equipped with a mechanical stirrer, a refrigerator, a heater and a thermometer, in accordance with Table 7, YD-128 (A) and PPG1000 (B) are placed and the temperature is maintained at 140 ° C for 3 hours. Then, bisphenol-A is added. (C) and methoxypropanol (D) and maintain the temperature at 125 ° C for 2 hours. Then the reaction mixture is cooled to 110 ° C. At 110 ° C. diethanolamine (E) was added and the reaction mixture was stirred for 30 minutes, and then the reaction product of Example 2 (F) was added. After cooling the reaction mixture to 100 ° C or less, formic acid (G) and deionized water (H) are added and mixed. With further cooling of the reaction mixture, the reaction product of Example 4 (I) is added and deionized water (J) is added slowly over 3 hours to obtain a dispersion of the reaction mixture in water. During the dispersion step, the reaction mixture is cooled to 50 ° C or less, from time to time injecting cooling water, since prolonged exposure to temperatures above 50 ° C reduces the stability of the aqueous dispersion. At the end of the dispersion step, the mixture is purged with nitrogen for 10 minutes to remove air bubbles from the reaction mixture, and the reaction mixture is stirred for 2 hours. During the above process, since a large amount of heat is generated after the addition of the amine as an exothermic reaction, the temperature increase is controlled precisely for the purpose of controlling said spontaneous heat release. The solids content in the product obtained in accordance with the above methodology is 36%.

Comparative Example 1

For comparison with the present invention, the reaction product of a conventional base resin and a conventional polymer crosslinking agent is obtained from the components shown in table 8, in accordance with the method, which is described below.

Table 8 Components for the preparation of the reaction product Component amount (A) YD-128 ¹⁾ 519.3 g (B) PPG1000 ²⁾ 199.4 g (C) Bisphenol-A 103.2 g (D) Methoxypropanol 37.7 g (E) Diethanolamine 146.6 g (F) The reaction product of example 3 575.5 g (G) Formic acid 24.5 g (H) Deionized water 1619.6 g (I) Deionized Water 774.2 g Total amount 4000.0 g ¹⁾ Bisphenol-A type liquid epoxy resin (molecular weight: 380; Kukdo Chemical Co., Ltd.)
²⁾ Propylene glycol (molecular weight: 1000; Korea Polyol Co., Ltd.)

In a separation vessel with a capacity of 5 l, equipped with a mechanical stirrer, a refrigerator, a heater and a thermometer, in accordance with Table 8, YD-128 (A) and PPG1000 (B) are placed and the temperature is maintained at 140 ° C for 3 hours. Then, bisphenol-A is added. (C) and methoxypropanol (D) and maintain the temperature at 125 ° C for 2 hours. Then the reaction mixture is cooled to 110 ° C. At 110 ° C, diethanolamine (E) was added and the reaction mixture was stirred for 30 minutes. Then the reaction mixture is heated for 1 h to 125 ° C, and then cooled to 110 ° C. Blowing air at a temperature of 110 ° C add the reaction product of example 3 (F). After cooling the reaction mixture to 100 ° C or less, formic acid (G) and deionized water (H) are added and mixed. With further cooling of the reaction mixture for 3 hours, deionized water (I) was slowly added to obtain a dispersion of the reaction mixture in water. During the dispersion step, the reaction mixture is cooled to 50 ° C. or less, injecting cooling water from time to time, because prolonged exposure to temperatures above 50 ° C. reduces the stability of the aqueous dispersion. At the end of the dispersion step, the mixture is purged with nitrogen for 10 minutes to remove air bubbles from the reaction mixture, and the reaction mixture is stirred for 2 hours. When carrying out the above process, since a large amount of heat is generated after the addition of the amine as an exothermic reaction, the temperature increase is controlled precisely for the purpose of controlling said spontaneous heat release. The solids content in the product obtained in accordance with the above methodology is 36%.

Examples 8-10 and comparative example 2

To perform examples 8-10 and comparative example 2, each cationic electrodeposition coating polymer composition was prepared by uniformly mixing the cationic electrodeposition coating resin, which was prepared in accordance with examples 5-7 and comparative example 1, respectively, for 24 hours, with a pigment paste composition in a mixing ratio of 4 to 1.

The composition of the pigment paste, which is used in the preparation of polymer compositions intended for coating by cationic electrodeposition, is obtained by the method described below.

680 parts by weight of YD-128, which is a liquid epoxy resin, 290 parts by weight of bisphenol-A, 89 parts by weight of dimethylethanolamine and 260 parts by weight of polymethylene polyphenylene isocyanate are placed in a 3-liter flask, and the reaction is carried out at 150 ° C for 2 hours. at a temperature of 60 ° C or less, 80 parts by weight of acetic acid are added and the reaction mixture is diluted with 300 parts by weight of deionized water to obtain a pigment resin dispersion. To 260 parts by weight of the obtained pigment resin dispersion, 450 parts by weight of deionized water, 270 parts by weight of titanium dioxide, 74 parts by weight of aluminosilicate, 24 parts by weight of carbon black and 16 parts by weight of dibutyltin oxide are added to it while stirring. The mixture is vigorously mixed in a mixer and a pigment paste composition is obtained.

Testing

Coating by cationic electrodeposition is carried out for 2 min at a static voltage of 300 V on steel sheets obtained by cold rolling (90 mm × 200 mm), the surface of which is treated with a surface treatment agent based on zinc phosphate, and compositions are used to obtain coatings cationic electrodeposition method according to examples 8-10 and comparative example 2, respectively. The resulting coating layer is washed with water and cured in an oven at 160 ° C. for 20 minutes to obtain a coating layer with a uniform thickness. Testing the coating obtained by the method of cationic electrodeposition, and the properties of the coating, which are determined by the results of the testing, are shown below in table 9.

Table 9 The results of determining the properties of the coating Properties Example 8 Example 9 Example 10 Comparative
example 2 Notes External
view Gloss ¹⁾ 66 66 64 65 Larger values mean more gloss. Roughness ²⁾ (Ra) 0.22 0.22 0.23 0.23 Smaller values mean better smoothness. Mechanical properties / adhesive properties Shock ³⁾ (3/8 inch) 1 kg ×
45 cm 1 kg ×
45 cm 1 kg ×
45 cm 1 kg ×
45 cm Higher values mean better properties. Cliff ⁴⁾ 7 mm 7 mm 7 mm 7 mm Bend ⁵⁾ Good Good Good Good 2 mm or less Curing ability Abrasion using methyl isobutyl ketone ⁶⁾ 25 times
or
more 25 times
or
more 30 times
or
more 20 times
or
more Corrosion resistance Resistance to salt fog ⁷⁾ 0.5 0.6 0.4 0.6 500 h 0.8 0.9 0.8 1,0 1000 h ¹⁾ Gloss: ASTM D523
²⁾ Roughness: Determined using a roughness tester, Surtronic 3+ (Taylor-Hobson Co., Ltd)
³⁾ Shock: ASTM D2794
⁴⁾ Open: ISO 1520
⁵⁾ Bending: ASTM D522
⁶⁾ Abrasion using methyl isobutyl ketone:
The test coating is rubbed with a cloth or tissue paper soaked in a solvent (methyl isobutyl ketone) until the coating is damaged. “20 or more” means that the coating is not damaged, at least after 20 rubbing, which indicates that the coating is cured.
⁷⁾ Salt spray resistance: ASTMB117

As shown in Table 9, the best curing ability was obtained in Example 10. As you can see, excellent curing ability is achieved thanks to the composition of the polymer crosslinking agent, which increases the density during curing, in particular due to the composition of the polymer crosslinking agent, which includes a modified Mannich reaction a polyol compound obtained from glycidyl ether and amine; and a barium salt of phenol, accelerating the curing reaction. Greater abrasion using methyl isobutyl ketone means better cure ability. Corrosion resistance is evaluated using a test using salt spray. Smaller values obtained during the salt spray test mean better corrosion resistance. As shown in table 9, example 8, which uses the polymeric crosslinking agent of the present invention, shows better corrosion resistance than example 9, where only barium catalyst is used. Example 10, where both the polymer crosslinking agent of the present invention and the barium catalyst of the present invention are used, shows the best corrosion resistance. As a result, when a dispersion of resin in water is used in a paint intended for cationic electrodeposition, excellent corrosion resistance and curing ability are achieved, while properties such as surface smoothness and mechanical and adhesive properties of the coating are equivalent to the corresponding values or exceed the corresponding values for conventional compositions .

Industrial Applicability

The present invention relates to a highly functional polymer composition for producing coatings by cationic electrodeposition, which has improved corrosion resistance and curing ability. Since the composition of the present invention contains a polyol compound derived from glycidyl ether and amine and a functionalized polyisocyanate derivative and uses a polymer curing catalyst containing metal, the composition of the present invention provides the coating with improved corrosion resistance and curing ability compared to with a polymer composition intended for the production of coatings by the cationic electrodeposition method, in which chnuyu base resin and crosslinking agent resin.

Claims (9)

1. The polymer composition for producing coatings by the method of cationic electrodeposition, which includes from 20 to 70 parts by weight a polymeric crosslinking agent containing a reaction product of a polyol as one compound obtained from glycidyl ether and an amine with a derivative of a polyisocyanate in which functional groups are blocked; from 30 to 80 parts by weight base resin; and from 0.1 to 10 parts by weight a polymer curing catalyst containing a metal, wherein the polyol compound obtained from glycidyl ether and an amine is the product of the reaction of a phenol derivative, an amine derivative and formalin derivative by the Mannich reaction. 2. The composition according to claim 1, where the phenol derivative is one or more compounds selected from the group consisting of cresol, butylphenol, octylphenol, nonylphenol and phenol; and the derivative of the amine compound is one or more compounds selected from the group consisting of ethylenediamine, trimethylenediamine, hexamethylene diamine, octamethylene diamine, diethylene triamine, triethylenetetramine, tetraethylene pentamine and methaxyldiamine. 3. The composition according to claim 1, where the reaction product of the Mannich reaction is a compound of the following formula 1:

wherein each R is independently a phenol derivative. 4. The composition according to claim 1, where the polyol as one compound obtained from glycidyl ether and amine is a compound of formula 2, which is the product of the Mannich reaction of a hydroxyl-containing derivative of an amine compound and a derivative of a glycidyl ether compound; and the amount of polyol as one compound obtained from glycidyl ether and amine is from 1 to 20 wt.% by weight of the polymer crosslinking agent:

wherein each R _{1 is} independently a phenol derivative, each R _{2 is} independently a glycidyl ester derivative, and R ₃ is a hydroxyl-containing derivative of an amine compound. 5. The composition according to claim 4, where the hydroxyl-containing derivative of the amine compound is selected from the group consisting of monoethanolamine, diethanolamine, monoisopropanolamine, di-isopropanolamine, monoethylethanolamine and monomethylethanolamine; and the derivative of glycidyl ether is selected from the group consisting of phenyl glycidyl ether and butyl glycidyl ether. 6. The composition according to claim 1, where the derivative of the polyisocyanate compound whose functional groups are blocked is the product of the interaction of the derivative of the diisocyanate compound and the hydroxyl-containing acrylate derivative or derivative of the alcohol compound; and the amount of the derivative of the polyisocyanate compound is from 80 to 99% by weight of the amount of the polymer crosslinking agent. 7. The composition according to claim 6, where the derivative of the diisocyanate is selected from the group comprising 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-methylene bis (phenyl diisocyanate), tetramethylene diisocyanate and hexamethylene diisocyanate; the hydroxyl-containing acrylate derivative is 2-hydroxyethyl methacrylate; and the alcohol derivative is selected from the group consisting of ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, trimethylol propane and propylene glycol. 8. The composition according to claim 1, where the metal is selected from the group which contains zirconium, zinc, calcium, lead, tin, bismuth, cobalt, titanium, aluminum, chromium and barium; and the metal is present in the form of a salt or in the form of a chelate. 9. The composition according to claim 1, where the metal-containing polymer curing catalyst includes a barium salt of phenol or barium chelate with phenol.