MIXTURES OF HYDROFLUORCARBONS AND ACIDS AS FOAM BLOWING AGENTS

摘要

A method of preparing polyurethane or polyisocyanurate from compositions comprising reacting and foaming a mixture of at least one polyol and isocyanate which react to form polyurethane or polyisocyanurate foams in the presence of a blowing agents which comprises: a hydrofluorocarbon or at least one compound selected from the group consisting of propane, n-butane, isobutene, n-pentane, isopentane, neopentane, cyclopentane, acetone, dimethyl ether, and inert gases; an acid; and, optionally, water.