The TPU of this invention contains unsaturation in its polymeric backbone. The unsaturation can be present in the
soft segment or in the hard segment or in both the soft and hard segments of the TPU. The TPU can be molded like a
thermoplastic, and can be subsequently crosslinked by
exposure to
electron beam
irradiation into thermoset articles having excellent
chemical resistance, dimensional stability, set properties,
heat resistance, oxidative resistance, and
creep resistance. In one embodiment, the TPUs of this invention are the
reaction product (1) a hydroxyl terminated intermediate, (2) a polyisocyanate, (3) a saturated glycol chain
extender, and (4) a glycol chain
extender containing carbon-carbon double bonds, such as the allyl moieties present in
trimethylolpropane monoallyl
ether. In another embodiment of this invention, the
thermoplastic polyurethane which is crosslinkable by e-beam
irradiation is comprised of the
reaction product of (1) a saturated hydroxyl terminated intermediate, (2) an unsaturated hydroxyl terminated intermediate, wherein the unsaturated hydroxyl terminated intermediate contains carbon-carbon double bonds, (3) a polyisocyanate, and (4) a saturated glycol chain
extender.