Polyurethane elastomer production method

The present invention provides a polyurethane elastomer production method characterized by supplying a prepolymer mixture, which is obtained by separately synthesizing and mixing a urethane prepolymer obtained by reacting a polyisocyanate component containing TDI and a polyol component of a high molecular weight at a prescribed NCO/OH equivalent ratio and a urethane prepolymer obtained by reacting a polyisocyanate component containing TDI and a polyol component of a low molecular weight at a prescribed NCO/OH equivalent ratio, to a thin film distillation device, distilling the unreacted TDI contained in the prepolymer mixture to reduce the content of the unreacted TDI to 0.4 mass % or less, and thereafter obtaining a mixture and thermally curing a composition obtained by blending a main agent containing the mixture and a curing agent. The polyurethane elastomer obtained by using said production method has a moderately long pot life, excellent workability, is not susceptible to thermal deformation at a use environment temperature, and performs with excellent abrasion resistance, mechanical strength, rebound resilience, and the like.