Low density rapid-setting polyurethanes

Claim 1

A solid, polyurethane article having a bulk density of less than about 0.7 g/cm 3 and which is substantially free of large internal air voids and surface imperfections resulting from the admixture of a composition comprising (A) a rapid-setting polyurethane-forming composition which produces a polyurethane which can be demolded, without the application of an external source of heat, within 5 minutes after admixture of the components of the polyurethane-forming composition, (B) as a light weight filler component, hollow spheres or microballoons of a copolymer of vinylidene chloride, acrylonitrile and divinyl benzene in an amount to provide the polyurethane composition with a bulk density of less than about 0.7 g/cm 3 , said spheres or microballoons having a density of from about 0.03 to about 0.45 grams/cc and a particle size of from about 10 to about 100 microns, and (C) as a viscosity reducing component, a liquid aromatic or halogenated aromatic compound in a quantity sufficient to provide the mixture of Components (A), (B) and (C) with a viscosity of less than about 2000 centipoises at 25° C.