Waterborne polyurethanes with urea-urethane linkages

摘要

Waterborne polyurethanes possessing urea-urethane linkages that are not separated by any intervening carbon atoms may be obtained by using hydroxylamine as a chain extender. Isocyanate-terminated prepolymer possessing ionized or easily ionizable groups is reacted with NH2OH to form a polyurethane possessing urea-urethane linkages corresponding to the formula: The waterborne polyurethanes are useful in adhesive, coating and ink formulations and in the flexible package industry.