Permanent gas blown microcellular polyurethane elastomers

摘要

Microcellular polyurethane elastomers having sharply reduced or virtually no urea linkages may be prepared without resort to organic physical blowing agents by frothing a frothable mixture containing isocyanate reactive polyols and chain extenders, and a frothable isocyanate component. The isocyanate component is derived by reacting a stoichiometric excess of a di- or polyisocyanate with a polyol component containing an ultra-low unsaturation polyol. The froth-produced elastomers surprisingly exhibit greatly improved tear strengths, compression set, and other physical properties as compared to all water-blown microcellular elastomers of the same density.