| 摘要 |
The invention relates to a method for the production of rigid polyurethane foams by the reaction of a) polyisocyanates with b) compounds with at least two hydrogen atoms which are reactive with isocyanate groups, in the presence of c) foaming agents. The invention is characterized in that the compounds with at least two hydrogen atoms which are reactive with isocyanate groups contain at least one polyether alcohol bi) which can be produced by the reaction of aromatic amines with ethylene oxide and propylene oxide, wherein in a first step of the method, first propylene oxide and then ethylene oxide, or a mixture of ethylene oxide and propylene oxide, is added, and in a second step of the method, the remaining amount of propylene oxide is added using a basic catalyst. ® KIPO & WIPO 2009
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