摘要 |
Reaction injection molded polyurethanes are prepared employing a mixture of chain extenders, at least one of which is a hydroxyl-containing compound free of aliphatic amine hydrogen atoms such as, for example, ethylene glycol, or an aromatic amine hydrogen-containing compound which is free of aliphatic amine and at least one of which is an aliphatic amine-containing compound which contains at least one primary amine group such as an aminated polyoxypropylene glycol. |