GB1365629A - Production of flameproof foam plastics which contain urethane groups - Google Patents

Abstract

1365629 Polyurethane foams BAYER AG 10 April 1972 [10 April 1971] 16337/72 Heading C3R Polyurethane foams are prepared by reacting, in the presence of a blowing agent, a polyhydroxyl compound of M.W. 100 to 10,000 and a polyisocyanate which is a solution in 2,4- and/or 2,6-toluylene diisocyanate of 2 to 60% by weight of undistillable material, the undistillable material being the material remaining as residue after distillation of phosgenation products of 2,4- and/or 2,6-toluylene diamine, and in which in the polyisocyanate solution 1 to 45% by weight of the free NCO groups have been converted into biuret groups. The polyisocyanate solution may comprise the crude phosgenation product of 2,4- and/or 2,6-toluylene diamine, from which some of the toluylene diisocyanate may have been distilled off, which is subsequently treated to produce biuret groups. Alternatively undistillable material remaining after distillation of a toluylene diamine phosgenation product may be dissolved as such in distilled 2,4- and/or 2,6-toluylene diisocyanate before treatment of the solution to produce biuret groups. The polyhydroxyl compound is preferably a linear polyether, especially one in which at least 5% by weight of the OH groups are primary OH groups. Conventional catalysts, emulsifiers, pore size regulators, fillers, dyes, plasticizers and/or flame-retarding additives may be incorporated in the reaction mixture.