Patents by Inventor Barry C. Holdstock

Barry C. Holdstock has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Hydrogel contact lenses for permanent wear
    Patent number: 4492776
    Abstract: A process is disclosed for the preparation of hydrogel contact lenses having improved mechanical properties, said process comprising polymerizing, in the presence of an azo type initiator, a monomer mixture comprising from 25% to 50% by weight of N-vinyl pyrrolidone, up to 5% by weight of methacrylic or acrylic acid, 0.1 to 1% by weight of 1,3,5-tris(propenoxy)-2,4,6-triazine (TPT), or perhydro-2,4,6,-triketo-1,3,5,-tris (propene-2)-1,3,5-triazine (T.T.P.T.), as a cross-linking monomer, the balance being essentially hydroxy alkyl acrylate or methacrylate, wherein the alkyl group is ethyl or propyl.
    Type: Grant
    Filed: April 12, 1984
    Date of Patent: January 8, 1985
    Assignee: CooperVision, Inc.
    Inventors: Ivor B. Atkinson, Barry C. Holdstock
  • Hydrogel contact lenses for permanent wear
    Patent number: 4451630
    Abstract: A process is disclosed for the preparation of hydrogel contact lenses having improved mechanical properties, said process comprising polymerizing, in the presence of an azo type initiator, a monomer mixture comprising from 25% to 50% by weight of N-vinyl pyrrolidone, up to 5% by weight of methacrylic or acrylic acid, 0.1 to 1% by weight of 1,3,5-tris(propenoxy)-2,4,6-triazine (TPT), or perhydro-2,4,6,-triketo-1,3,5,-tris (propene-2)- 1,3,5 - triazine (T.T.P.T.), as a cross-linking monomer, the balance being essentially hydroxy alkyl acrylate or methacrylate, wherein the alkyl group is ethyl or propyl.
    Type: Grant
    Filed: June 16, 1983
    Date of Patent: May 29, 1984
    Inventors: Ivor B. Atkinson, Barry C. Holdstock
  • Preparation of cross-linked hydrogel copolymers for contact lenses
    Patent number: 4419463
    Abstract: The invention relates to soft contact lenses having a water content of at least about 45% and comprising a hydrated copolymer of a major proportion of an hydroxyalkyl acrylate or methacrylate, up to 12% by weight of an ethylenically unsaturated acid or anhydride, a minor proportion of a cross-linking monomer and a minor proportion of styrene or a substituted styrene, the free acid or anhydride groups being in salt form.
    Type: Grant
    Filed: March 16, 1982
    Date of Patent: December 6, 1983
    Inventors: Ivor B. Atkinson, Barry C. Holdstock
  • Cross-linked hydrogel copolymers for contact lenses
    Patent number: 4361657
    Abstract: The invention relates to soft contact lenses having a water content of at least about 45% and comprising a hydrated copolymer of a major proportion of an hydroxyalkyl acrylate or methacrylate, up to 12% by weight of an ethylenically unsaturated acid or anhydride, a minor proportion of a cross-linking monomer and a minor proportion of styrene or a substituted styrene, the free acid or anhydride groups being in salt form.
    Type: Grant
    Filed: November 29, 1979
    Date of Patent: November 30, 1982
    Assignee: Global Vision (U.K.) Ltd.
    Inventors: Ivor B. Atkinson, Barry C. Holdstock