GB1230573A - - Google Patents

Abstract

1,230,573. Polyurethane foams. DUNLOP CO. Ltd. 3 April, 1968 [5 April, 1967; 4 Nov., 1967], Nos. 15514/67 and 3743/68. Divided out of 1,230,378. Addition to 1,039,861. Headings C3C and C3R. A composite polyurethane foam is prepared by introducing into an open-pored polyurethane foam a liquid composition comprising one part of a polyurethane foam-forming mixture and subsequently a vapour comprising the complementary part of the polyurethane foam-forming mixture, the vapour comprising at least one ingredient necessary for the polyurethane foam reaction, and the liquid composition and the vapour being allowed to react or the vapour being allowed to function as a catalyst, to form a polyurethane foam within the open pored foam. The open pored foam may be a flexible foam which may be reticulated before or after the composite foam has been produced. The preferred vapour is steam but it may be an amine catalyst such as triethylamine or N-methyl morpholine. It is preferred to use the liquid composition comprising one part of the polyurethane foam forming mixture in the form of a polyurethane prepolymer. This prepolymer is usually spread on the surface of the open pored foam which is passed through rolls to secure uniform distribution'and then supported or suspended in a vessel in which the vapour is present. The foam may be compressed during the introduction of the vapour. Both the foams can be either a polyester or polyether based foam.