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Expired Canadian patentCanada

Low temperature shock resistant release liner

CA 2041576 C · Owner: Gates, Milton R. · Inventors: Gates, Milton R.; Shibahara, Norihito; Johnson, Michael A.

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

Release liners comprising support sheet and face layer, the face layer comprising one or more of the following: a copolymer of ethylene and at least one polar comonomer, or a copolymer of propylene and at least one polar comonomer, or blends of such copolymers. Such release liners provide low temperature shock resistance and smooth, substantially uniform release characteristics when applied to acrylic pressure-sensitive adhesives.

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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

  • Filed May 1, 1991 and granted August 7, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 1, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 1, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 1, 1991
GrantedAugust 7, 2001
Term endedMay 1, 2011
Patent numberCA 2041576 C
Classification (IPC)B32B27/32 +2 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedMay 1, 1991Patent grantedAug 7, 2001Term endedMay 1, 2011

Sources & verification

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