| abstract |
The present invention provides a method for producing a polyurethane emulsion for a one-pack type aqueous coating which is safe for the environment and excellent in productivity, storage stability, alkali resistance and solvent resistance of the film. The manufacturing method of the polyurethane emulsion for one-pack type aqueous coating agent of this invention reacts organic diisocyanate (al), high molecular polyol (a2), and carboxyl group-containing low molecular glycol (a3), and a carboxyl group-containing isocyanate group terminal urethane prepolymer (A ), A nonionic polar group-containing polyisocyanate (B) is mixed, and then the carboxyl groups in the system are neutralized with a neutralizing agent (C), and then the mixture is emulsified in water and a chain extension reaction with water or an amine is carried out. It is a step to perform. |