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Expired Canadian patentCanada

Slow growth tree-craze ethylene polymer compositions

CA 1185723 A · Owner: E. I. Du Pont De Nemours And Company · Inventors: Beasley, John K.; Urban, Edward J.

CIPO record

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

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Abstract From the Canadian patent

Propagation of electrical trees and water trees in electrical insulation made of ethylene homopolymers or copolymers with an unsaturated monomer is inhibited by the addition to the insulating composition of an organic carboxylic ester having at least one aromatic ring and at least three carboxylic ester groups, the ester being liquid at the operating temperature of the electrical equipment in which the insulation is used. The main utility of the inhibitors of this invention is in the primary insulation for power transmission cables especially, those used in high voltage applications.

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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 April 16, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 16, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 9, 1982
GrantedApril 16, 1985
Term endedApril 16, 2002
Patent numberCA 1185723 A
Classification (IPC)C08K5/12 +2 more

Timeline

Timeline From CIPO dates

1983198519871989199119931995199719992001Application filedSep 9, 1982Patent grantedApril 16, 1985Term endedApril 16, 2002

Sources & verification

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