Polyvinyl chloride/polyurethane foam composite elements, the productions thereof, and liquid, urethane-containing polyisocyanate mixtures which can be used to prepare the polyurethane foam

A composite element consisting essentially of

• A) at least one top layer of polyvinyl chloride or a polyvinyl chloride-containing polymer mixture, and
• B) a polyurethane foam,
• wherein the polyurethane foam (B) is prepared by reacting
• a) a urethane-containing, diphenylmethane diisocyanate-based polyisocyanate mixture containing from 15 to 32% by weight of NCO groups, this mixture itself being obtainable by reacting a diphenylmethane diisocyanate isomer or a mixture of diphenylmethane diisocyanate isomers and a polyphenyl-polymethylene polyisocyanate with at least one .alpha.,.beta.-olefinically unsaturated polyester having a molecular weight factor per double bond of from 150 to 3000, a functionality of from 2 to 6, a hydroxyl number of from 20 to 800 and an acid number of from 0 to 15, or a mixture of said .alpha.,.beta.-olefinically unsaturated polyester and a polyoxyalkylenepolyol having a functionality of from 2 to 4 and a hydroxyl number of from 20 to 400, with
• b) at least one relatively high-molecular-weight polyhydroxyl compound containing at least two reactive hydrogen atoms and
• c) if desired chain extenders and/or crosslinking agents, in the presence of
• d) a blowing agent,
• e) a catalyst and, if desired,
• f) assistants and/or additives.