use of nitroethan can reach, and 1 nitropropan to prevent the degradation in the manufacture of polyurethanes and as a propellant polyisocyanuraten steamed used chlorofluorocarbons

摘要

The invention relates to a method for inhibiting the degradation by dehydrohalogenation of hydrochlorofluorocarbons, such as for example the mixture of 123 and 123a, used as foaming agents during the formation reaction of foamed polyurethanes or polyisocyanurates starting from polyols and polyisocyanates. Prior to the reaction starting, a little amount of a stabilizing substance selected from the group consisting of nitromethane, nitroethane and 1-nitropropane is added to the reaction medium.