Solid, rapid-setting, rigid polyurethanes

Claim 1

A process for producing solid, rigid, polyurethane articles having a density of at least 1 g/cc, a percent elongation of less than 100, and which can be demolded within a period of about 5 minutes without the addition of an external source of heat, which process comprises 1. admixing, in the absence of a catalytic quantity of a catalyst for urethane formation, the components of a composition comprising A. an amine initiated polyol having an OH equivalent weight of from about 50 to less than about 250; B. an organic aromatic polyisocyanate; C. a liquid modifier compound having a boiling point above about 150° C selected from the group consisting of 1. a liquid partially capped, block or randomly formed polyoxyalkylene compound represented by the general formula ##EQU1##wherein each R is independently selected from saturated and unsaturated hydrocarbon groups having from about 1 to about 6, carbon atoms; R 1 , R 2 , ... and R n are independently hydrogen, an aryl group, an alkyl group or haloalkyl group, said alkyl or haloalkyl group having from about 1 to about 2 carbon atoms with the proviso that when R 1 , R 2 , ... R n is a haloalkyl group, it is present in a ratio of from about 0 to about 10 percent of the total R 1 , R 2 , ... R n groups, and x 1 , x 2 , ... x n are integers, the sum of which provides the partially capped polyoxyalkylene compound with a molecular weight of at least about 700; 2.