GB1344038A - Preparation of polyurethane foams - Google Patents

Abstract

1344038 Polyurethane foams SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 2 May 1972 20357/72 Heading C3R Polyurethane foams are prepared by mixing two packages (a) and (b) under foam forming conditions, package (a) comprising a polyether polyol prepared by the tertiary amino catalysis, to which polyether polyol has been added an acid, and a silicone oil, and package (b) comprises an organic polyisocyanate, and either package (a) comprises a polymerization catalyst or a polymerization catalyst is added to the reaction mixture formed by mixing package (a) with package (b). The polyether polyol is suitably prepared by reacting a polyol having at least 4 OH groups, e.g. sucrose with one or more alkylene oxides, e.g. a mixture of propylene oxide and ethylene oxide in the presence of a tertiary amino catalyst such as trimethylamine or N,N - dimethyl - 2 - aminoethanol. The added acid is preferably formic acid and is added in an amount which is at least 20% of the stoichiometric equivalent of the tertiary amine catalyst used in the preparation of the polyether polyol. The polymerization catalyst is suitably a tertiary amine such as triethylene diamine and/or dimethylcyclohexylamine. Foam-forming conditions may be created by including water in package (a) and/or trichlorofluoromethane in package (a) and/or package (b).