Aqueous cationic polyurethane having blocked NCO groups and process

摘要

Aqueous cationic polyurethane emulsions are prepared by reacting an isocyanate-terminated urethane prepolymer with an excess of a polyalkylene polyamine to form a polyurethane-urea-polyamine, and then partially reacting the free amino groups in said product with a blocked polyisocyanate having a single free isocyanate group, followed by mixing with an aqueous solution of an acid.