Thermoplastic polyurethane elastomers and polyurea elastomers made using low unsaturation level polyols prepared with double metal cyanide catalysts

A thermoplastic polyurethane or polyurea elastomer made by reacting an isocyanate-terminated prepolymer with a difunctional isocyanato-reactive chain-extender, the isocyanate-terminated prepolymer being the reaction product of a polyisocyanate and a polyether diol prepared utilizing a double metal cyanide complex catalyst and having a molecular weight of between about 2000 and about 20,000, said diol having an end group unsaturation level of no greater than 0.04 milliequivalents per gram of diol the equivalent ratio of NCO groups on said diisocyanate to active hydrogen groups on said diol plus chain extender being between about 1:0.7 and about 1:1.3, and the molar ratio of chain extender to diol being between about 0.15:1 and about 75:1.

A method of fabricating a thermoplastic elastomer which comprises the steps of:

• (a) fabricating a diol having a molecular weight of between about 2,000 and about 20,000 and having a level of end group unsaturation of no greater than 0.04 milliequivalents per gram of diol, said polyol being fabricated in the presence of a double metal cyanide catalyst, (b) reacting said diol with a diisocyanate to produce an isocyanate-terminated prepolymer, and
• (c) reacting said isocyanate-terminated prepolymer with a difunctional isocyanato-reactive chain extender in a mold or in an extruder in order to produce a soft elastomer characterized by a Shore A hardness of between about 10 and about 70, with the proviso that when the molecular weight of the diol is less than 4,000, then the polyol has an ethylene oxide content of less than 35 weight based upon the weight of the diol.