PROCESS FOR PRODUCTION OF POLYURETHANE EMULSION FOR AQUEOUS ONE-PACKAGE COATING MATERIALS

摘要

[PROBLEMS] To provide a process for the production of a polyurethane emulsion for aqueous one-package coating materials which are safe with concern for the environment and excellent in productivity and storage stability and in the water resistance and solvent resistance of film. [MEANS FOR SOLVING PROBLEMS] A process for the production of a polyurethane emulsion for aqueous one-package coating materials, characterized by reacting an organic diisocyanate (a1) with a high-molecular polyol (a2) and a carboxyl-containing low-molecular glycol (a3) to prepare a carboxyl-containing isocyanato-terminated urethane prepolymer (A), mixing the prepolymer (A) with a nonanionic polyisocyanate (B), blocking the whole or part of the isocyanato groups of the mixture with a blocking agent (C), neutralizing the carboxyl groups contained in the system with a neutralizing agent (D), emulsifying the resulting mixture in water, and, if necessary, subjecting the mixture to chain lengthening reaction.