| 摘要 |
PURPOSE:To obtain a molded foam having a low density and excellent soundproofing and vibration-damping properties by reacting a mixture of three specified polyols with a polyisocyanate in the presence of water under conditions of a specified NCO index. CONSTITUTION:A process for preparing a polyurethane foam by reacting a polyisocyanate component with a polyol component in the presence of water as a blowing agent, wherein the polyol component comprises a mixture of 60-98wt.% polyoxyalkylenepolyol and/or derivative thereof modified with an ethylenically unsaturated monomer each of which has a functionality of 2-4, an average equivalent weight of 800-3000 and a total oxyethylene content of below 50wt.%, 1-30wt.% polyhydroxyl compound having a functionality of 2-8 and an average equivalent number of 30-500 and 1-10wt.% polyoxyalkylenepolyol having a functionality of 1-8, an average equivalent number of 1000-3000 and a total oxyethylene content of at least 50wt.%, and the NCO index is 40-85. |
