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Crosslinked siloxane-urethane polymer contact lens

  • US 5,426,158 A
  • Filed: 04/14/1994
  • Issued: 06/20/1995
  • Est. Priority Date: 09/28/1988
  • Status: Expired due to Fees
First Claim
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1. A compatible, interpenetrating-polymer-network composition which comprises(I) 95-50% by weight of the total composition of a siloxane-urethane polymer formed by the reaction of;

  • (A) a di- or poly-hydroxyalkyl substituted alkyl polysiloxane having a number average molecular weight between about 200 and about 10,000 and(B) a substantially compatible, aliphatic, cycloaliphatic or aromatic di- or tri-isocyanate,wherein the total number of hydroxyl groups in component (A) is substantially stoichiometrically equivalent to the total number of isocyanate groups in component (B), and with the proviso that an effective crosslinking amount of (A) or (B) or both (A) and (B) is present and possesses a functionality greater than two, and(II) 5-50% by weight of the total composition of a vinyl polymer or copolymer obtained by the free-radical polymerization of a vinyl monomer or mixture of vinyl monomers;

    wherein said siloxane-urethane polymer (I) is formed by a polymerization which occurs prior to the polymerization reaction which forms said vinyl polymer (II).

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