The present invention relates to moldings based on reaction products of polyols and isocyanates. Specifically, the present invention relates to molding compositions comprising the following components: a) one or more polyisocyanates, b) one or more polyols, c) one or more catalysts catalyzing the reaction between polyisocyanate and polyol, d) one or more pyrogenically produced oxides of a metal or of a metalloid, and characterized by comprising, as component, e) at least one or more siloxanes, moldings obtainable with use of the molding compositions, and also a process for the production of the moldings.