| 摘要 |
A paint composition for cathodic electrodeposition in the form of an aqueous solution or dispersion which is essentially a resin prepared by the reaction of (A) a polymer; (B) an alcohol; (C) an epoxy resin; (D) an amine; and a polyisocyanate. The paint composition is prepared as follows: (a) first reacting a maleated conjugated diene polymer as an addition reaction compound of a maleic anhydride, with a homopolyer, a random copolymer, a block copolymer or a graft copolymer of a conjugated diene selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, chloroprene and cyclopentadiene, said homopolymer or copolymer of the conjugated diene having a number average molecular weight of 200 to 100,000, with (b) an alcohol having the tertiary amino group or a mixture of said alcohol and a monohydroxyl compound having 1 to 18 carbon atoms to obtain a semi-esterified product (B), and second, reacting said product (B) with (c) an epoxy resin having two equivalents or more of epoxy groups in proportion to one equivalent of carboxyl group in said product (B) to obtain a resultant product (C), and third reacting said product (C) with (d) a primary or secondary amine to obtain a resultant product (D), and finally reacting said product (D) with (e) a partially blocked polyisocyanate having intramolecularly two or less of free isocyanate groups and one or more of blocked isocyanate groups in one molecule; and, (f) further neutralizing the resultant resin with an acid to render the resultant resin soluble or dispersible in water.
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