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Expired Canadian patentCanada

Dispersant composition for magnetic media

CA 1310654 C · Owner: Kimball, David Jay · Inventors: Sylvester, Judith Mervane; Kimball, David Jay

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

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Abstract From the Canadian patent

An improved dispersant for magnetic media comprising the reaction product of a phosphate ester and an alkali siliconate silylalkylphosphonate is described. The, dispersant can provide comparable magnetic properties in magnetic media at lower levels than are necessary for currently employed phosphate ester dispersants. A magnetic coating composition and a process for producing magnetic recording media, based on said improved dispersant are also, disclosed.

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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 November 24, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 24, 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 29, 1987
GrantedNovember 24, 1992
Term endedNovember 24, 2009
Patent numberCA 1310654 C
Classification (IPC)C07F9/40 +1 more

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedMay 29, 1987Patent grantedNov 24, 1992Term endedNov 24, 2009

Sources & verification

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