Aqueous cationic coating from amine-epoxy adduct, polyamide, and semiblocked polyisocyanate, acid salt

Abstract

A cationic electrophoretic coating composition comprises an aqueous medium and a resinous binder dispersed therein, said resinous binder being prepared by contacting at least one starting material with a partially blocked polyisocyanate compound at a temperature of 40.degree. to 130.degree. C in the weight ratio of from 5 to 9 of the former to from 5 to 1 of the latter, and subsequently by neutralizing the resulting product with an acid, said starting material being at least one selected from the group consisting of: 1. a mixture of a reaction product prepared by reacting an epoxy resin with a basic amino compound having at least one basic amino group, and a polyamide having at least one basic amino group, in the weight ratio of from 1 to 9 of the reaction product to from 9 to 1 of the polyamide, and 2. a further reaction product prepared by mixing said reaction product with said polyamide at a temperature of 50.degree. to 200.degree. C in the weight ratio of from 1 to 9 of the reaction product to from 9 to 1 of the polyamide, Said partially blocked polyisocyanate compound having at least one blocked isocyanate group in the molecule and an average of more than zero to not more than one free isocyanate group per molecule.

Dependencies are inferred from the claim text.