Aqueous-based polyurethane compositions and method of preparation

摘要

Aqueous-based polyurethane elastomer compositions which can be used as adhesives and a method of preparing same are described. The polyurethane compositions are prepared by chain extending an isocyanate-terminated urethane prepolymer with an equivalent excess of water in the presence of a monofunctional isocyanate group blocking agent to provide a reaction mixture having a desired adhesive capability and thereafter adding additional blocking agent to the reaction mixture in an equivalent amount at least substantially equal to the remaining equivalent amount of unreacted isocyanate groups in the prepolymer.