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Expired Canadian patentCanada

Process for hydroxymethylation

CA 1284665 C · Owner: Kwiatkowski, Charles Thomas · Inventors: Delmar, Eric George; Kwiatkowski, Charles Thomas

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

Disclosed and examplified is a general method for producing methylol compounds by the reaction of an organometallic compound with formaldehyde in which the formaldehyde is generated in situ from and by the use of a high molecular weight linear formaldehyde homopolymer.

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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 4, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 4, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJuly 10, 1985
GrantedJune 4, 1991
Term endedJune 4, 2008
Patent numberCA 1284665 C
Classification (IPC)C07C33/24 +1 more

Timeline

Timeline From CIPO dates

19861989199219951998200120042007Application filedJuly 10, 1985Patent grantedJune 4, 1991Term endedJune 4, 2008

Sources & verification

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