| abstract |
Thermoplastic polyurethanes are formed from a polydiene diol, preferably a hydrogenated polybutadiene diol, having from 1.6 to 2 terminal hydroxyl groups per molecule and a number average molecular weight between 500 and 20,000, an isocyanate having two isocyanate groups per molecule, and optionally a chain extender having two hydroxyl groups per molecule. The thermoplastic polyurethane composition is prepared by a prepolymer method. preferably a solventless prepolymer method using the branched chain extender. |