| 摘要 |
The invention relates to a process for the preparation of compact or cellular polyurethanes by reacting relatively high-molecular-weight polyhydroxyl compounds and optionally chain extenders and/or crosslinking agents with a liquid polyisocyanate composition containing urethane groups, obtainable from mixtures of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates and linear, branched or cyclic, saturated or olefinically unsaturated, low-molecular-weight monoalcohols, to the liquid polyisocyanate compositions containing urethane groups which can be used for this purpose, and to the use thereof for the preparation of preferably highly crosslinked polyurethanes, in particular rigid PU (moulded) foams. |
