rimary hydroxyl groups than amino groups, and (4) about 0.05 to 25 parts by weight of an amine catalyst, and (5) about 0.5 50 parts by weight of monofluorotrichloromethane, optionally in the presence of (C) water and/or further inorganic or organic blowing agents, foam stabilizers and other additives usual in the production of cellular polyurethanes. 2.