| 摘要 |
There is now provided a polyol composition containing a polyol having polyester linkages, a number average molecular weight of 400 or more, and at least about 8 php of a silicone-containing surfactant polymer. Either mixed into the polyol composition at the time of foaming, mixed into an isocyanate, or both, is an aliphatic or cycloaliphatic C4-C7 hydrocarbon. The polyol composition is used to make a polyisocyanate based closed cell rigid foam by reacting an organic isocyanate and the polyol composition in the presence of an aliphatic or cycloaliphatic C4-C7 hydrocarbon blowing agent.
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