Abstract: A process for the production of polyurethane foams, in particular for the production of composite articles by back-foaming a plastics film as covering layer by the reaction ofa) one or more polyisocyanates withb) a polyol component which is free from salt groups in the presence ofc) at least one blowing agent,d) alkali metal carboxylates ande) from 0.01 to 30% by weight, based upon the weight of component b), of one or more organic compounds which are different from components a) through d), which are free from tertiary amino groups, metal and phosphorus and which have a dipole moment above 2.0 Debye.