Abstract: What are described are (a) a composition suitable for production of polyurethane foam, comprising at least one polyisocyanate component, a polyol component, optionally a catalyst that catalyses the formation of a urethane or isocyanurate bond, optionally blowing agents, where the composition additionally comprises hydrocarbons HC, Si-free surfactant and optional polyalkylsiloxane, (b) a process for producing polyurethane foam using hydrocarbons HC, Si-free surfactant and optional polyalkylsiloxanes, (c) the polyurethane foam thus obtainable and (d) the use thereof.

Abstract: The invention relates to a trimerization catalyst system comprising at least 50% by weight of potassium octoate and a hydroxy-group-free and amino-group-free solvent which, under the reaction conditions, is inert toward the isocyanates used, to its use for the trimerization of isocyanates to give isocyanurates and/or polyisocyanurates, and to a process for production of PIR foams using the inventive trimerization catalyst system and PIR foams.