Process for the production of new polysiloxane-polyoxyalkylene copolymers with reduced burning properties

Claim 1

In a polyurethane foam made from isocyanates, compounds with two or more isocyanate reactive hydrogen atoms, stabilizers, blowing agents and optionally catalysts, the improvement wherein said stabilizer is one produced by (a) reacting organopolysiloxanes corresponding to the general formula: ##STR7## wherein m represents an integer from 1 to 100, Z, which may be the same or different, represents a C 1 -C 5 alkyl radical, a C 6 -C 15 aryl radical, a siloxyl or a siloxanyl radical or the group --R--Y--H, R represents a C 1 -C 6 alkylene radical which may contain one or more hetero atoms, Y represents --NR'--, --O--, ##STR8## or --S-- and R' represents a hydrogen atom or C 1 -C 6 alkyl or C 5 -C 9 cycloalkyl radical, with polyisocyanates in an NCO:YH equivalent radio of at least 2, (b) heating the NCO-containing addition products thus obtained at from 110° to 160° C. to cause branching and, (c) reacting the resulting branched NCO-containing addition products of relatively high molecular weight with a monofunctional polyether corresponding to the formula: R"--(OC.sub.n H.sub.2n).sub.x --OH wherein n represents an integer from 2 to 4, x represents an integer from 1 to 100 and R" represents a monofunctional C 1 -C 20 hydrocarbon radical optionally containing oxygen or nitrogen as hetero atoms, in an NCO:OH ratio of from 0.8 to 1.2.