Cationic modified epoxy resin emulsion and preparation method and application thereof

An epoxy resin emulsion, cationic technology, applied in coatings, electrophoretic coatings, etc., can solve the problems of different distribution ratios of original paint liquid and paint film components, low surface charge density of latex particles, poor emulsion stability, etc. , to achieve the effects of improving poor stability, reducing latex particle size, and increasing paint film hardness

Inactive Publication Date: 2011-03-16
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The first method is direct mechanical blending to stir the two resins and an external crosslinking agent evenly to prepare a two-component water-soluble cathodic electrophoretic coating, but it is difficult to avoid poor stability. different question than
The second method is to make a composite resin through the connection between chemical bonds, which increases the compatibility of the resin. At present, low molecular weight epoxy resin is mostly used, and the paint film performance of low molecular weight epoxy resin is not as good as that of higher molecular weight epoxy resin. Film performance, if a higher molecular weight epoxy resin is used, the grafting active points can be increased, and the paint film performance can be improved; however, due to the decrease in the relative concentration of ionic groups, the latex particle size is relatively small in the water-emulsion type cathodic electrophoretic coating stock solution obtained through self-emulsification. Large, the surface charge density of latex particles is low, and the absolute value of Zeta potential is small, so the stability of the emulsion is poor, which limits its application time and affects coating construction

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 1) Add 40g of epoxy resin and 30g of solvent propylene glycol methyl ether into a four-necked flask equipped with a condenser, nitrogen protection, stirring paddle and dropping funnel, and heat up to 100-105°C. After the resin is completely dissolved, start stirring. Condensed water, nitrogen gas;

[0039] 2) When the temperature rises to 113±2°C, add dropwise 31.4g of a mixture of all monomers, initiators, and solvents (7.5g of methyl methacrylate, 8.5g of butyl acrylate, and 2.0g of glycidyl methacrylate , 2.0g of 2-hydroxyethyl acrylate, 1.0g of acrylamide are dissolved in advance with 10g of propylene glycol methyl ether as a cosolvent, and 0.4g of dibenzoyl peroxide as an initiator) into the reaction system, and the dropping speed is controlled. After the addition is completed, the temperature is maintained at 117±1°C during the period, and the total grafting reaction time is 5h;

[0040] 3) After 5 hours of grafting reaction, lower the temperature to 95-100°C, ad...

Embodiment 2

[0047] 1) Add 50g of epoxy resin and 20g of solvent propylene glycol methyl ether into a four-necked flask equipped with a condenser, nitrogen protection, a stirring paddle and a dropping funnel, heat up to 100-105°C, and start stirring after the resin is completely dissolved. Condensed water, nitrogen.

[0048] 2) When the temperature rises to 113±2°C, add dropwise 30.4g of a mixture of all monomers, initiators, and solvents (including 7.0g methyl methacrylate, 8.0g butyl acrylate, and 3.0g glycidyl methacrylate , 1.0g of acrylate-2-hydroxyethyl ester, 1.0g of acrylamide are pre-dissolved with 10g of propylene glycol methyl ether as a cosolvent, and 0.4g of initiator dibenzoyl peroxide) into the reaction system. After the addition is completed, the temperature is maintained at 117±1°C during the period, and the total grafting reaction time is 5h;

[0049] 3) After 5 hours of grafting reaction, lower the temperature to 95-100°C, add 10.78g of diethanolamine dropwise, control ...

Embodiment 3

[0053] 1) Add 30g of epoxy resin and 30g of solvent propylene glycol methyl ether into a four-necked flask equipped with a condenser, nitrogen protection, stirring paddle and dropping funnel, and heat up to 100-105°C. After the resin is completely dissolved, start stirring. Condensed water, nitrogen gas;

[0054] 2) When the temperature rises to 113±2°C, add dropwise 40.6g of a mixture of all monomers, initiators, and solvents (including 11.0g methyl methacrylate, 13.0g butyl acrylate, and 4.0g glycidyl methacrylate , 1.0g of acrylate-2-hydroxyethyl ester, 1.0g of acrylamide are pre-dissolved with 10g of propylene glycol methyl ether as a cosolvent, and 0.6g of dibenzoyl peroxide as an initiator) into the reaction system. After the addition is completed, the temperature is maintained at 117±1°C during the period, and the total grafting reaction time is 5h;

[0055] 3) After 5 hours of grafting reaction, lower the temperature to 95-100°C, add 8.62g of diethanolamine dropwise, ...

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PUM

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Abstract

The invention discloses a cationic modified epoxy resin emulsion and a preparation method and application thereof, and belongs to the technical field of methods for preparing resin emulsion for cathodic electrophoretic coatings. The prior emulsion of the cathodic electrophoretic coatings has low stability, and the film hardness and corrosion resistance cannot completely meet the use requirement. The preparation method comprises the following steps: grafting allyl monomers provided with epoxy groups, amide groups and hydroxyl groups onto a main chain of bisphenol A epoxy resin by a solution radical polymerization method to obtain graft copolymer; adding an organic secondary amine compound to open ring and aminate epoxide groups on the graft copolymer, wherein the dosage of the organic secondary amine compound accounts for 70 to 100 percent of the total mass of the epoxide groups; and adding organic acid for neutralization, and dispersing in water to form the cationic modified epoxy resin emulsion. The emulsion provided by the invention is applied to the preparation of the cathodic electrophoretic coatings, improves the stability in the storage and use of the cathodic electrophoreticcoatings, and can directly perform electrophoretic painting; and a paint film has good corrosion resistance and improves hardness.

Description

technical field [0001] The invention belongs to the technical field of preparation methods of resin emulsions for cathodic electrophoretic coatings, and in particular relates to a cationic modified epoxy resin emulsion and its preparation method and application. Background technique [0002] Electrophoretic coating is a kind of water-based coating, which is a new technology for coating construction developed in the 1960s. Because cathodic electrophoretic coating has the advantages of excellent corrosion resistance, high penetration rate, high leveling property, high decoration, high degree of coating automation, and low environmental pollution, it has been paid more and more attention by people. [0003] In cathodic electrophoretic coatings, resin emulsion is the main film-forming substance, which determines the film performance of cathodic electrophoretic coatings. At present, epoxy resin is mostly used as the main film-forming substance. Because of its high adhesion and e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F283/10C08F8/32C08J3/03C09D151/08C09D5/44
Inventor 李效玉任光哲王海侨
Owner BEIJING UNIV OF CHEM TECH
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