Conversion of cyclic polycarbonate oligomers to linear polycarbonates initiated by phosphine-disulfide product or precursor thereof
CA 2085655 A1 · Owner: General Electric Company · Inventors: Krabbenhoft, Herman O.; Brunelle, Daniel J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Cyclic polycarbonate oligomers are polymerized to linear polycarbonates by the action of a salt prepared by the reaction of a triarylphosphine or triaryl phosphite with an organic disulfide, preferably an aryl disulfide. The reactants which form the salt may be incorporated in the cyclic polycarbonate composition, and interreact when the composition is heated to form the active initiating species.
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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 December 17, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 17, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 17, 2014.
- 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.