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Expired Canadian patentCanada

Method for reducing pvc polymer buildup in polymerization reactors

CA 1095645 A · Owner: Continental Oil Company · Inventors: Durr, Albert M. Jr.; Weimer, Dean R.

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Abstract From the Canadian patent

A method for preventing polymer buildup in the polymerization reactor during the suspension polymerization of vinyl chloride monomer to form polyvinyl chloride polymer and copolymers, the method comprising coating reactor surfaces in contact with the reaction medium with a material selected from the group consisting of alumina dithiooxamide, and mixtures of these prior to carrying out this polymerization.

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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 February 10, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 10, 1998.
  • 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 17, 1977
GrantedFebruary 10, 1981
Term endedFebruary 10, 1998
Patent numberCA 1095645 A
Classification (IPC)C08F2/18 +2 more

Timeline

Timeline From CIPO dates

1978198119841987199019931996Application filedMarch 17, 1977Patent grantedFeb 10, 1981Term endedFeb 10, 1998

Sources & verification

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