CATIONIC MICRO-GEL AND PREPARATION METHOD THEREOF, AND ELECTRODEPOSITION PAINT COMPOSITION CONTAINING THE SAME

摘要

PURPOSE: A cationic micro-gel and preparation method thereof and an electrodeposition paint composition containing the same are provided to improve flatness and corrosion resistance especially at the corners of the film by using a product resulted from a reaction between quaternary ammonium salts and polyepoxide. Further, the cationic micro-gel has excellent compatibility with a cationic electrodeposition resin, participates in the hardening reaction and suppresses the generation of craters. CONSTITUTION: The preparation method of a cationic micro-gel comprises: (a) reacting an aliphatic and an aromatic diisocyanate with a tertiary amine having a hydroxyl group to obtain a tertiary amine intermediate having an isocyanate group; (b) reacting a polyepoxide having a molecular weight of 200-2000 and containing two epoxy groups per one molecule with a secondary amine having a hydroxyl group to obtain a polyepoxide-amine reaction products having a hydroxyl group; (c) reacting the tertiary amine intermediate with the polyepoxide-amine reaction products and thereto adding an acid to obtain quaternary ammonium salts; (d) dispersing the quaternary ammonium salts into a deionized water to prepare a water dispersion; (e) adding polyepoxide to the water dispersion to obtain a water dispersion which contains micro-gel through gelation; and (f) drying the micro-gel containing water dispersion to recover the micro-gel products.