VERFAHREN ZUR HERSTELLUNG VON POLYURETHAN- WEICHSCHAUMSTOFFEN

The prodn. of flexible foam comprises reacting di- or poly- isocyanates with cpds. contg. at least two NCO-reactive H atoms in the presence of a blowing agent (II) and opt. other additives. (II) is a mixt. contg. 1,1,1,2-tetrafluoroethane (TFE) and at least one other cpd. selected from 1,1-difluoroethane (DFE) and readily volatile organic cpds. with a b.pt. below 105 (pref. below 80) degrees C, i.e. ketones, acetates, aliphatic and cyclic hydrocarbons, halogenated hydrocarbons or N-contg. hydrocarbons. Also claimed is a blowing agent compsn. (II) for this process, contg. 50-95 wt% TFE and 5-50 wt% DFE and/or other cpds. as above Pref. compsn. (II) contains 50-95 pts. wt. TFE and 5-50 pts. wt. other blowing agents, pref. 50-95 pts. wt. TFE and 5-50 pts. wt. of a mixt. of DFE and other volatile cpds. with a b.pt. below 80 degrees C, or a mixt. of 84-88 wt% TFE and 12-16 wt% DFE.