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Expired Canadian patentCanada

Process for the production of paper

CA 1324705 C · Owner: Johansson, Hans Erik · Inventors: Svending, Per Johan; Johansson, Hans Erik

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

A process for the production of paper by forming and dewatering a suspension of cellulose containing fibers and optional fillers on a wire in the presence of a cationic silica based sol and a cationic polymeric retention agent. The cationic polymeric retention agent is cationic guar gum or a cationic synthetic polymer such as cationic polyacrylamide. The combination of cationic silica sol and cationic polymeric retention agent gives improved retention of fines and fillers and eases drainage.

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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 November 30, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 30, 2010.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 7, 1989
GrantedNovember 30, 1993
Term endedNovember 30, 2010
Patent numberCA 1324705 C
Classification (IPC)D21H21/10 +2 more

Timeline

Timeline From CIPO dates

1990199319961999200220052008Application filedMarch 7, 1989Patent grantedNov 30, 1993Term endedNov 30, 2010

Sources & verification

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