Block copolymers interpolymerized with in situ polystyrene and process for preparation thereof
CA 2247670 A1 · Owner: Wollum, Mark H. · Inventors: Wollum, Mark H.; Graves, Daniel F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for interpolymerizing a vinyl aromatic hydrocarbon polymer and a block polymer is disclosed. The process includes the following steps: a) forming a block polymer precursor of at least one polymeric block containing conjugated diene monomer contributed units in the presence of an anionic initiator and in an inert diluent, the block polymer precursor having living ends; (b) thereafter adding to the block polymer precursor a charge of a vinyl aromatic hydrocarbon monomer and an additional charge of an anionic initiator to simultaneously form (1) a block polymer having a terminal block formed from the charge of vinyl aromatic hydrocarbon monomer attached to the block polymer precursor …
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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 17, 1998. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended September 17, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 17, 2020.
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Timeline
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.