AIR FROTHED POLYURETHANE FOAMS

摘要

1460863 Flexible polyurethane foams DOW CHEMICAL CO 13 March 1974 11237/74 Heading C3R Flexible polyurethane foam having a density of less than 15 lb./cu.ft. are prepared by frothing a mixture comprising (1) an active hydrogen containing composition containing (1a) from 50 to 100 p.b.w. of a polyether polyol having an OH functionality of 2 to 3 and containing an internal block of at least 3 moles of ethylene oxide per active hydrogen atom and/or an end-cap of at least 2 moles of ethylene oxide per active hydrogen atom and having an OH equivalent weight of 1000 to 2500 and (1b) from 0 to 50 p.b.w. of an aromatic diamine and/ or glycol and (2) a polyisocyanate which is (2a) an NCO-terminated prepolymer having a functionality of from 2 to 4À5 resulting from the reaction of an organic diisocyanate with one or more hydroxy compounds having 2 to 8 hydroxyl groups per molecule and an OH equivalent weight of 53 to 1000, (2b) polymeric polyisocyanates, (2c) crude aromatic diisocyanates or a mixture of two or more of (2a), (2b) or (2c), the mixture not containing a silicone cell control agent, the frothing being accomplished by mixing an inert gas with the mixture and components (1) and (2) being used so as to provide an NCO : OH ratio of from 0À85 : 1 to 2À0 : 1. The inert gas is preferably air. Curing of the frothed compositions takes place at room temperature or elevated temperatures, if desired with the composition coated on a substrate.