Production of particulate polyimide polymers
CA 2004070 A1 · Owner: Eisenbraun, Allan A. · Inventors: Klobucar, Dirk W.; Eisenbraun, Allan A.; Zumstein, Ronald C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure, Described is a process for producing in particu-, late form, aromatic polyimides based on one or more 2,2bis4-(aminophenoxy)phenylhexafluoropropanes. The process involves forming, heating and agitating in a medium composed of dipolar aprotic solvent and liquid aromatic hydrocarbon solvent, a homogeneous solution of a polyamic acid derived from a substantially equimolar mixture of (i) an aromatic tetracarboxylic dianhydride and (ii) a 2,2-bis4-(aminophenoxy)phenylhexafluoropropane such that a separate phase of particulate aromatic polyimide is formed in such medium. The process avoids difficulties caused by the tendency of the wet polyimide polymer to agglomerate …
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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
- Filed November 28, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 28, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 28, 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.