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Expired Canadian patentCanada

Method for the polymerization of vinyl monomers

CA 1102489 A · Owner: Shin-Etsu Chemical Co. Ltd. · Inventors: Katusima, Sensaku; Koyanagi, Shunichi; Hasegawa, Niichiro

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Abstract From the Canadian patent

A method for polymerizing a vinyl monomer in a polymerization reactor is provided. The inner walls of the polymerization reactor and other surfaces come into contact with the monomer and are coated with an aqueous liquid containing at least one alkali metal or ammonium salt of an anionic dye of the sulfonic carboxylic acid form and having a pH value adjusted not to exceed 7 by aid of a pH adjusting agent. The thus coated surfaces are dried with heat before the polymerization is conducted. The method serves to reduce the deposition of polymer scale on those surfaces and, consequently, improves the productivity as well as the quality of polymer product.

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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 June 2, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 2, 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.
FiledJanuary 16, 1978
GrantedJune 2, 1981
Term endedJune 2, 1998
Patent numberCA 1102489 A
Classification (IPC)C08F2/00 +2 more

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedJan 16, 1978Patent grantedJune 2, 1981Term endedJune 2, 1998

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