IONOMERS FOR IMPROVED COMPRESSION SET IN CERTAIN COPOLYMERS
First Claim
1. A block copolymer having improved compression set comprising 40-98 wt % soft segment, 1.9-20 wt % hard segment, and 0.05-3 wt % monofunctional ionic endgroups which provide improved compression set in said block copolymer.
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Accused Products
Abstract
Block copolymer having improved compression set comprising 40-98 wt-% soft segment, 1.9-20 wt-% hard segment, and 0.05-3 wt-% monofunctional ionic endgroups. The incorporation of ionomers into diisocyanate-based thermoplastic polyurethane materials greatly improves compression set with little impact on the overall TPU formulation. A typical formulation for making the block copolymer contains 84.2% polydimethylsiloxane, 12.9% diisocyanate, 2.9% diamine chain extender, 0.15% sodium 2-[bis(2-hydroxyethyl)amino]ethylsulfonate, and 0.05% isethionic acid. The polymeric material may be configured, for instance, as a contact lens, prosthetic spinal nucleus, orthopedic bearing surface, gasket, or sealant.
9 Citations
13 Claims
- 1. A block copolymer having improved compression set comprising 40-98 wt % soft segment, 1.9-20 wt % hard segment, and 0.05-3 wt % monofunctional ionic endgroups which provide improved compression set in said block copolymer.
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10. A method of making a block copolymer having improved compression set, which method includes the steps of:
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providing a reaction vessel containing an inert solvent, rapidly adding to said solvent in said reaction vessel, in the absence of catalyst, an amino-terminated polydimethylsiloxane, an aliphatic diisocyanate, an ionic surface-modifying endgroup, and, optionally, an alkylene diol chain extender, at ambient temperature, and removing the resulting polymer from the reaction vessel within 60 minutes of adding the reactants thereto. - View Dependent Claims (11, 12)
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Specification