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Expired Canadian patentCanada

Magnetic recording medium

CA 1104434 A · Owner: Fuji Photo Film Co. Ltd. · Inventors: Tamai, Yasuo; Nakamura, Matsuaki; Ogawa, Hiroshi

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

A magnetic recording medium comprising a non-magnetic support having thereon a magnetic recording layer containing a finely divided ferromagnetic powder, a binder and at least one 1,2-epoxyalkane represented by the general formula (I) (I), wherein R represents an alkyl group having 10 to 30 carbon atoms; in an amount of about 0.05 to about 3 parts by weight per 100 parts by weight of the ferromagnetic powder.

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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 July 7, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 7, 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.
FiledSeptember 6, 1978
GrantedJuly 7, 1981
Term endedJuly 7, 1998
Patent numberCA 1104434 A
Classification (IPC)G11B5/72 +2 more

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedSep 6, 1978Patent grantedJuly 7, 1981Term endedJuly 7, 1998

Sources & verification

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