PRODUCTION OF POLYURETHANE FOAMS

In a process for producing polyurethane foams, preferably semirigid polyurethane foams and flexible, semirigid and rigid polyurethane integral foams, a) at least one modified or unmodified organic polyisocyanate is reacted with b) at least one relatively high molecular weight compound con taining at least two reactive hydrogens and, if desired, c) low molecular weight chain extenders and/or crosslinkers in the presence of d) blowing agents, preferably water and/or (cyclo)alkanes, e) a catalyst mixture comprising, according to the invention, e') from 35 to 65 parts by weight of di-n-octyltin bis(2-ethylhexyl thioglycolate) and e'') from 65 to 35 parts by weight of mono-n-octyltin tris(2-ethylhexyl thioglycolate) and also, if desired, e''') cocatalysts selected from the group of tertiary amines, alkali metal and alkaline earth metal salts of monocarboxylic acids having from 1 to 20 carbon atoms and f) if desired, additives, with the reaction for forming the polyurethane integral foams being carried out in a closed mold with compaction at a degree of compaction of from 1.4 to 8.3.