Copolymerization process and optical copolymer produced therefrom
CA 2091903 C · Owner: Brouwer, Wilfridus M. · Inventors: Brouwer, Wilfridus M.; Brand, Johannes
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing a copolymer suitable for use in an optical element which comprises the step of radically-polymerizing a composition which comprises at least one first monomer represented by formula (I), at least one second monomer represented by any one of formulas (II, III and IV) and 0.005 to 1.0 weight , percent of said polymerizable composition of an organic chain transfer agent having a chain transfer coefficient at 50-60°C of greater than 0.5 with acrylic monomer or styrenic monomer; in the presence of a radical polymerization initiator is disclosed. Also , disclosed is a copolymer suitable for use as an optical element obtained by the foregoing process and an optical …
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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 September 5, 1991 and granted November 12, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 5, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 5, 2013.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.