Abstract: The invention relates to a continuous process for the preparation of polyurethanes/polyureas, in which the components of a starting reaction composition are applied individually and/or as a mixture in a thin film to an inner region of a hot surface of a rotating body A so that the thin film flows over the hot surface of the rotating body A to an outer region of the hot surface of the rotating body A, the thin film leaves the hot surface as polyurethane/polyurea-containing reaction composition and, after leaving the hot surface, the reaction composition is abruptly cooled, a polyisocyanate component and a polyol/polyamine component being present as components of the starting reaction composition, the temperature of the hot surface being 70 to 400° C. and the abrupt cooling of the reaction composition being at least 30° C.