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Expired Canadian patentCanada

Post-cross-linked polymeric gels

CA 1303785 C · Owner: Gregor, Harry P. · Inventors: Dalven, Paul I.; Gregor, Charles D.; Samuelsen, Edgar

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Abstract From the Canadian patent

Cross-linked polymeric gels or films are prepared by dissolving in a suitable solvent a linear polymer or polymers at least one of which is predominantly (at least 80%) made from monomers containing pendant amidocarbonyl or oxycarbonyl groups. For the cross-linking reaction are present either hydroxyl groups, present as either pendant groups from the polymer, or as low molecular weight polyols; or amino groups, present as either pendant groups from the polymer, or as low molecular weight diamines or polyamines. Either no catalyst is present or a strongly acidic catalyst (which may also be a pendant group on a polymer) is used. The solvent is removed by coagulation and/or drying and the dry …

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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 June 16, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 16, 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.
FiledApril 9, 1986
GrantedJune 16, 1992
Term endedJune 16, 2009
Patent numberCA 1303785 C
Classification (IPC)C08L33/04 +1 more

Timeline

Timeline From CIPO dates

19871990199319961999200220052008Application filedApril 9, 1986Patent grantedJune 16, 1992Term endedJune 16, 2009

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