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Expired Canadian patentCanada

Hydrogel-forming polymers

CA 1311095 C · Owner: T R Developments Limited · Inventors: Tahan, Menashe

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Hydrogel-forming Polymers, Hydrogel-forming polymers for contact lenses and intraocular lenses having increased toughness despite high equilibrium water content comprise a hydrophilic monomer (eg. an N-vinyl lactam) and a polyunsaturated polymeric cross-linking agent. UV-absorbers are also disclosed which are bound in the polymer structure so as to be inextractable, some undergoing photo-Fries re-arrangement on exposure to UV-radiation so as to become UV-absorbers in the re-arranged form.

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted December 8, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 8, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 18, 1985
GrantedDecember 8, 1992
Term endedDecember 8, 2009
Patent numberCA 1311095 C
Classification (IPC)B29D11/00 +2 more

Timeline

Timeline From CIPO dates

19861989199219951998200120042007Application filedDec 18, 1985Patent grantedDec 8, 1992Term endedDec 8, 2009

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.