| abstract |
The present invention relates to a process for the preparation of polyurethane foams in which polyisocyanates are reacted with compounds having a molecular weight of from 400 to 10,000 and containing at least two isocyanate-reactive hydrogen atoms, in the presence of water and/or organic blowing agents, catalysts, melamine as a flameproofing agent, and other flameproofing agents selected from phosphonic acid esters having the general formula ##STR1## wherein R 1 is C 1 -C 6 alkyl, C 2 -C 6 unsaturated alkyl, C 5 -C 12 cycloalkyl, C 7 14 C 15 aralkyl, or C 6 -C 12 aryl, R 2 and R 3 are independently C 1 -C 6 alkyl, C 2 -C 6 unsaturated alkyl, C 5 -C 12 cycloalkyl, C 7 -C 15 aralkyl, or C 6 -C 12 aryl, or R 2 and R 3 together are C 2 -C 4 alkylene, R 4 is C 1 -C 6 alkylene, C 5 -C 12 cycloalkylene, C 7 -C 15 aralkylene, or C 6 -C 12 arylene, R 5 is C 2 -C 6 alkylene, C 5 -C 12 cycloalkylene, C 7 -C 15 aralkylene, or C 6 -C 12 arylene, and n is an integer of from 1 to about 100. n The process is optionally carried out in the presence of compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight of from 32 to 399, and known surface-active additives and auxiliaries. |