Patent ID: 6716890
Filing Date: 2004-04-06
Classification: B29C,B29K,C08G

Abstract:
A method for producing a durable polyurethane foam, comprising the steps of:(1) preparing a reaction mixture comprising: (a) a polyol mixture of (i) about 10 to 70 percent by weight total polyols of a polyether polyol having up to 85 percent ethylene oxide groups, and having a hydroxyl number in the range of about 20 to 60 and a functionality from 2.8 to 3.5, and (ii) about 30 to 90 percent by weight total polyols of a graft polyol having a ratio of styrene to acrylonitrile of about 70 to 30, and having a hydroxyl number in the range of about 25 to 60 and a functionality from 2.5 to 3.0; (b) toluene diisocyanate wherein the isocyanate index is in the range of 95 to 135; and (c) from about 1.2 to 2.5 parts per hundred parts polyol of water as a blowing agent; and (2) allowing said reaction mixture to react while held at a pressure of about 1.0 to 1.5 bar (absolute) so as to form the polyurethane foam.