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Expired Canadian patentCanada

Process for preparing high bulk density resins

CA 1304538 C · Owner: Oxy Vinyls, L.P. · Inventors: Hong, Paul Oonyong

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

Spherical particles of vinyl resin having high bulk density can be prepared by the suspension polymerization process by using as a dispersant an alkyl hydroxy cellulose having a viscosity of from about 1000 to about 100,000 cps. A suitable dispersant is a hydroxypropyl methyl cellulose polymer having the formula:, where n is from about 300 to about 1500.

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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 30, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 30, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 14, 1986
GrantedJune 30, 1992
Term endedJune 30, 2009
Patent numberCA 1304538 C
Classification (IPC)C08F2/20 +1 more

Timeline

Timeline From CIPO dates

19871990199319961999200220052008Application filedMay 14, 1986Patent grantedJune 30, 1992Term endedJune 30, 2009

Sources & verification

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