Process for preparing copolymers
CA 2063473 C · Owner: Mahabadi, Hadi K. · Inventors: Kovacs, Gregory J.; Ng, T. Hwee; Mahabadi, Hadi K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a process for preparing copolymers which comprises in the order stated: (1) adding monomers containing unsaturated carbon-to-carbon bonds, a first polymerization initiator a second polymerization, initiator, and a solvent to a reaction vessel; (2) purging the resulting solution with an inert gas; (3) sealing the reaction vessel and pressurizing it by addition of an inert gas to a pressure of from about 20 to about 600 kilopascals over ambient atmospheric pressure; (4) maintaining the temperature within the pressurized reaction vessel at a temperature of from about 50 to about 100°C for a period of from about 60 to about 300 minutes; (5) thereafter maintaining the temperature …
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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 19, 1992 and granted September 22, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 19, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 19, 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.