Process for the production of polyurethane foam

Abstract From the Canadian patent

A polyurethane foam is produced using acetone as an auxiliary blowing agent. A polyol, an isocyanate water, acetone and a catalyst for catalyzing the formation of polyurethane are mixed to produce an unfoamed liquid mixture, which is then retained in bulk form, preferably in an open-topped reaction vessel for, a dwell time during which an exothermic reaction occurs and the liquid foams. Finally, the foaming liquid is spread on to a surface on which it is allowed to expand and form a solid polyurethane foam material. Significant reductions in the amount of auxiliary blowing agent can be achieved, as compared with conventional formulations using methylene or CFC's as auxiliary blowing agents.