| 摘要 |
An improved method for preparing polyesterurethanes with p-phenylene diisocyanate is realized by (1) first reacting a polyester with a molar excess of p-phenylene diisocyanate to provide an isocyanate-terminated polyesterurethane, which is then (2) further reacted with additional amounts of polyester used to make the polyesterurethane. The first stage polymer (1) as prepared, is liquid and stable at temperatures of reaction with additional polyester, so that a continuous commercial process is possible without the stability problems faced when reacting all of the polyester and p-phenylene diisocyanate together to form the desired polyesterurethane. |
