A process for the production of clear copolyesters of terephthalic acid, naphthalenedicarboxylic acid and ethylene glycol
CA 2282463 A1 · Owner: Eastman Chemical Company · Inventors: Maag, Maureen Clare; Stoots, Robert Lewis Jr.; Bowers, David Taylor
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a process comprising polymerizing repeat units derived from an acid component comprising terephthalic acid and naphthalenedicarboxylic acid and at least one glycol in the presence of less than about 10 ppm sodium carbonate and between about 10 and about 60 ppm phosphorus. Polyesters formed via the process of the present invention display surprisingly good clarity and color.
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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 February 27, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 27, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 27, 2020.
- 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.