Suspension polymerization of polyurethanes and spin-molding the powder product thereof

摘要

Polyurethanes having a fine particle size are prepared according to a suspension process wherein silicone surfactants are utilized and the polymerization is carried out under agitation in a nonaqueous and a nonsolvent system according to either a two step, or preferably a one step process. The produced suspension-type polyurethanes are generally powders or very small granules and, therefore, can be utilized directly for rotational or spin molding processes wherein they are cured through the use of specific curing agents. Additionally, generally any suspension polyurethanes having a plasticity value of at least 2,000 square mm. at 150 DEG C, can be cured in a rotational or spin molding operation utilizing specific curing agents and curing at a temperature below the decomposition temperature of the polyurethane, for example, below 250 DEG C.