| 摘要 |
Rigid foams containing urethane and isocyanurate groups are produced by reacting a) polyisocyanates with b) compounds containing at least two hydrogen atoms which are reactive towards isocyanates and having a molecular weight of from 400 to 10,000, and c) optionally compounds containing at least two hydrogen atoms which are reactive towards isocyanates and having a molecular weight of 32-399, in the presence of d) NCO trimerisation catalysts and e) mixtures of n-pentane and/or isopentane with cyclopentane as blowing agent, and optionally f) further blowing agents and auxiliaries and additives known per se, and are used as insulating materials. |
