| 摘要 |
PURPOSE: To shorten a molding time and to improve strength by a method wherein after a polyurethane raw material compsn. with a specified compsn. is molded at an enough temp. where crosslinking bondings are generated in a prepolymer, the resulting shaped article is demolded and it is kept at a specified temp. until curing is completed. CONSTITUTION: A compsn. comprising 1 mole polymerized glycol with a no. average mol.wt. of 400-3,000, at least 1.3 mole org. diisocyanate, a blocking agent with at least 3 per molecule active hydrogen which can react with isocyanate group and a diol with a mol.wt. of at most 250 and with aliph. hydroxyl groups, is prepd. This compsn. is crosslinked at a specified temp. by prepolymn. and after a crosslinked shaped article is demolded, it is kept at a temp. of 25-150 deg.C until curing is completed to prepare a cured polyurethane elastomer product. |
