| 摘要 |
Closed cell rigid polyurethane foams are produced by reacting a) a polyol component with b) a polyisocyanate having an NCO content of from about 20 to about 48% by weight. The polyol component a) includes: 1) from 40 to 80% by weight, based on the total weight of polyol component a), of a sucrose or sorbitol initiated polyether having a molecular weight o f from about 300 to about 800; 2) from 3 to 40% by weight, based on the total weight of polyol component a), of an aromatic amine initiated polyether having a molecular weight of from about 300 to about 800; 3) from 3 to 40% by weight, based on the total weight of polyol component a), of an aliphatic amine initiated polyether having a molecular weight of from about 200 to about 800; 4) from 3 to 40% by weight, based on the total weight of polyol component a), of a linear polyether having a molecular weight of from about 500 to about 1500; optionally, 5) other compounds containing at least isocyanate-reactive hydrogen atoms having a molecular weight of from about 150 to about 12,500; 6) a catalyst; 7) water; 8) a foaming agent; and optionally, 9) a processing aid and/or additive.
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