| abstract |
This invention relates to a process for the preparation of polyurethane foams comprising reacting polyisocyanates with compounds containing at least two active hydrogen atoms and having a molecular weight of 400 to 10,000 selected from polymer-modified polyols and polyols containing predominantly primary hydroxyl groups, in the presence of water and/or organic blowing agents, catalysts, and flameproofing agents having the formula <IMAGE> in which R1 and R2 are independently hydrogen or C1-C4 alkyl; X is -(CH2)n- wherein n is an integer of from 0 to 5 (preferably 0 or 1), -CH=CH-, a branched alkylene group, an arylene group, or (NH)m wherein m is 1 or 2; Y is -CN or <IMAGE> wherein R1 and R2 are as defined above or both R2 together form a bond. The reaction is optionally carried out in the presence of other flameproofing agents, compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight of 32 to 399, and known surface-active additives and auxiliaries. |