PRODUCTION OF POLYURETHANE-UREA RESIN FOR SYNTHETIC LEATHER OR ELASTIC YARN

摘要

PROBLEM TO BE SOLVED: To produce the subject low-hardness resin good in touch feeling, rich in recovery properties after stretching and excellent in chlorine resistance by reacting a specific isocyanate group-terminated prepolymer with a chain extender in a solvent, then further adding an isocyanate compound thereto and removing the solvent. SOLUTION: (A) An isocyanate group-terminated prepolymer obtained by reacting a high-molecular weight active hydrogen compound such as polyoxytetramethylenediol with (B) an isocyanate compound such as diphenylmethane diisocyanate is reacted with (B) a chain extender such as ethylenediamine in a solvent to thereby provide (C) a polymer. (D) An isocyanate compound is further added thereto and the solvent is then removed to produce the objective resin. The component D is preferably an isocyanate group- terminated prepolymer prepared by reacting a high-molecular weight active hydrogen compound having 2-8 active hydrogen-containing groups with a polyisocyanate compound in a ratio so as to provide an excess of the isocyanate groups over hydroxyl groups.