The preparation of polyurethanes comprises reacting (A) optionally modified organic polyisocyanates, (B) high molecular weight compounds containing at least two reactive hydrogen atoms and (C) optional low molecular weight chain extenders or cross-linking agents, in the presence of (D) catalysts, (E) propellants and (F) flame retardants, and optionally in the presence of (G) processing aids and/or additives. Complexes of cyclodextrins and amines are used as (D).
