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Expired Canadian patentCanada

Aluminum treatment

CA 1112135 A · Owner: Oxy Metal Industries Corporation · Inventors: Nagae, Yoshio; Utsumi, Takashi

CIPO record

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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 chromium-free treatment for aluminum imparts corrosion resistance and paint receptivity to the surface. The process is sequential and includes a first contact with an aqueous alkaline solution (pH above 10) containing complexed iron ion, water rinsing, and then contact with an aqueous acidic organic tannin-containing composition.

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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 10, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 10, 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.
FiledMarch 30, 1978
GrantedNovember 10, 1981
Term endedNovember 10, 1998
Patent numberCA 1112135 A
Classification (IPC)C23C22/66

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedMarch 30, 1978Patent grantedNov 10, 1981Term endedNov 10, 1998

Sources & verification

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