Production process for polyimide fibers
CA 2002147 A1 · Owner: Morikawa, Shuichi · Inventors: Nagahiro, Taizo; Ohta, Masahiro; Tamai, Shoji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the production of polyimide fibers and polyimide fibers obtained by the process. The process includes thermal or chemical imidation of a polyamic acid which has been obtained by reacting a specific diamine and a particular tetracarboxylic dianhydride in the presence of a dicarboxylic anhydride represented by the following formula:, wherein Z represents a divalent group selected from the group consisting of monocyclic aromatic groups fused, polycyclic aromatic groups and non-fused polycyclic aromatic groups with aromatic rings bonded together directly or via a crosslinking member.
Read the whole patent
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
- Filed November 3, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 3, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 3, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.