THERMOPLASTIC POLYURETHANE ELASTOMER AND PROCESS FOR ITS PREPARATION

A thermoplastic polyurethane elastomer is described as a polyblend of polyurethane and nitrile rubber which, without containing a plasticiser, has a Shore A hardness of from 55 to 70. The polyurethane component contains at least 50 % by weight of polyisocyanate; the acrylonitrile content in the rubber component is 34 mol-%, and the polyurethane:nitrile rubber ratio is from 30:70 to 40:60 % by volume. Furthermore, a preparation process is indicated in which polyurethane having a Shore A hardness of from 80 to 90 and a minimum polyisocyanate content of 50 % by weight is processed to give a polyblend with a nitrile rubber having a viscosity ML 1 + 4,100 DEG C = 50 and an acrylonitrile content of 34 mol-% with a polyurethane: rubber ratio by volume of 30:70 to 40:60 % by mixing and kneading at 180 to 215 DEG C.