Process for production of poly (arylene thioether) containing phthalic anhydride groups
CA 2092334 C · Owner: Nishihata, Naomitsu · Inventors: Nishihata, Naomitsu; Katto, Takayuki; Ichikawa, Yukio
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 a poly(arylene thioether) containing phthalic anhydride groups wherein a dihalogen-substituted aromatic compound is reacted with an alkali metal sulfide in a polar organic solvent containing water to produce the poly(arylene thioether) is disclosed. This process comprises causing a monohalogen-substituted phthalic compound to exist in a polymerization reaction system, and controlling a ratio, a/b of the number of moles, a of the charged dihalogen-substituted aromatic compound to the number of moles, b of the charged alkali metal sulfide within a range of 0.8 < a/b < 1.
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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 March 24, 1993 and granted September 30, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 24, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 24, 2015.
- 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
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.