Method of preparing polyurethane foam of low thermal conductivity

摘要

Closed cell polyurethane foams, useful as thermal insulation for refrigerators and the like, are prepared by blending a polyisocyanate, a polyol and a suspension of at least one solid alkaline reagent, preferably sodium hydroxide, in an inert carrier liquid having a suitable viscosity. Preferred carrier liquids include polyepoxides and polyoxyalkylenediamines. The alkaline reagent reacts with and removes the carbon dioxide employed as a blowing agent, thus decreasing the thermal conductivity of the foam.