Abstract: A process for producing a rigid PU or PIR foam can be performed by contacting at least one organic polyisocyanate having two or more isocyanate functions with an isocyanate-reactive mixture. The isocyanate-reactive mixture has at least one polyol, water and at least one emulsifier, wherein the emulsifier has at least one alkoxylated aromatic alcohol. The parent aromatic alcohol has at least 6 and at most 40 carbon atoms and also at least one OH function. At most ? of the carbon atoms of the parent aromatic alcohol are not aromatic, and at least one aromatic unit in the parent aromatic alcohol must bear an OH function.

Abstract: A process for producing polyurethane foam by reacting at least one polyol component with at least one isocyanate component in the presence of at least one blowing agent and of one or more catalysts that catalyze the isocyanate-polyol and/or isocyanate-water reactions and/or the isocyanate trimerization, wherein the reaction is conducted in the presence of selected polyether-siloxane copolymers, is described.

Abstract: The present invention relates to a composition suitable for production of rigid polyurethane or polyisocyanurate foams, said composition comprising at least one isocyanate component, at least one polyol component, at least one foam stabilizer, at least one urethane and/or isocyanurate catalyst, optionally water and/or blowing agent, and optionally at least one flame retardant and/or further additives, which comprises at least two different varieties 1 and 2 of polyether siloxanes as foam stabilizers, and to the use of this composition for production of foamed polyurethane or polyisocyanurate materials, preferably rigid foams.

Abstract: The present invention relates to a composition suitable for production of rigid polyurethane or polyisocyanurate foams, said composition comprising at least one isocyanate component, at least one polyol component, at least one foam stabilizer, at least one urethane and/or isocyanurate catalyst, optionally water and/or blowing agent, and optionally at least one flame retardant and/or further additives, which comprises at least two different varieties 1 and 2 of polyether siloxanes as foam stabilizers, and to the use of this composition for production of foamed polyurethane or polyisocyanurate materials, preferably rigid foams.