| 摘要 |
<p>Process for the preparation of rigid polyurethane foams comprising the step of reacting an organic polyisocyanate with an isocyanate-reactive material in the presence of a blowing promotor which is an isocyanate-reactive cyclic carbonate or cyclic urea, and in the presence of an inert, insoluble organic liquid and a metal salt catalyst and a polyether polyol of average nominal functionality 2 to 6 and number average equivalent molecular weight between 1000 and 2000.</p> |
