Butadiene copolymer
CA 2097453 A1 · Owner: Yamamoto, Keisaku · Inventors: Saito, Yuichi; Wakatsuki, Kizuku; Tsuji, Mitsuji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An elastomeric butadiene copolymer prepared by a process which comprises copolymerizing butadiene a, polyvinyl aromatic compound and optionally styrene in a hydrocarbon solvent in the presence of an organolithium polymerization initiator and subjecting the resulting copolymer having lithium at the polymer end or ends to a coupling reaction with a trifunctional or tetrafunctional coupling agent, said butadiene copolymer satisfying the following conditions: (a) the content of styrene is at most 50 % by weight, (b) the content of vinyl bonds in the butadiene portion is from 10 to 90 % by weight (c) the, molecular weight distribution curve obtained by a high performance liquid chromatography …
Read the whole patent
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 June 1, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended June 1, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 1, 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
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.