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Expired Canadian patentCanada

Gelling composition with sulfonated diphenyldiissocyanate

CA 1237131 A · Owner: National Starch And Chemical Corporation · Inventors: Ray-Chaudhuri, Dilip K.; Chiao, Wen B.

CIPO record

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Abstract From the Canadian patent

Novel gelling agents are prepared by reacting diphenyldiisocyanates with sulfur trioxide in a molar concentration of about 1:2. When the sulfonated diphenyldiisocyanate is added to water in concentrations above 2%, a gel is produced which is stable under acidic conditions at pH levels of about 4 or less.

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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 24, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 24, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 12, 1984
GrantedMay 24, 1988
Term endedMay 24, 2005
Patent numberCA 1237131 A
Classification (IPC)B01F17/00 +2 more

Timeline

Timeline From CIPO dates

1985198819911994199720002003Application filedOct 12, 1984Patent grantedMay 24, 1988Term endedMay 24, 2005

Sources & verification

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