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Expired Canadian patentCanada

Process for purification of polyether

CA 1268481 C · Owner: Asahi Kasei Kogyo Kabushiki Kaisha · Inventors: Yamamatsu, Setsuo; Aoshima, Atsushi; Tonomura, Shoichiro

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Abstract From the Canadian patent

A process for purifying a polyalkylene ether which comprises mixing a polyalkylene ether or a mixture of a polyalkylene ether and an organic solvent containing a heteropoly acid and/or its salt with at least one solvent for purification selected from hydrocarbons having 3 to 15 carbon atoms or halogenated hydrocarbons having 1 to 15 carbon atoms and separating by precipitation the phase composed mainly of the heteropoly acid and/or its salt, and a process wherein the polyalkylene ether or a mixture of a polyalkylene ether and an organic solvent containing a heteropoly acid and/or its salt is brought into contact with a solid adsorbent capable of adsorbing the heteropoly acid and/or its salt …

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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 May 1, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 1, 2007.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 8, 1985
GrantedMay 1, 1990
Term endedMay 1, 2007
Patent numberCA 1268481 C
Classification (IPC)C07C41/36 +2 more

Timeline

Timeline From CIPO dates

19861989199219951998200120042007Application filedNov 8, 1985Patent grantedMay 1, 1990Term endedMay 1, 2007

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