Halogenated butyl rubber graft copolymers
CA 2067561 C · Owner: Polysar Rubber Corporation · Inventors: Hopkins, William; Ho, Chai H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for grafting halogenated butyl rubbers with polymers based on conjugated diolefin monomers is provided which comprises mixing a first solution of halogenated butyl rubber with a second solution of a living alkali metal terminated polymer based on conjugated diolefin monomers and having a number average molecular weight of at least 40,000 at a temperature of from about -10°C to about 80°C for a period of time of from about 30 minutes to about 24 hours whereby the graft copolymer is formed. Rubber compositions comprising the halogenated butyl rubber graft copolymers upon vulcanization exhibit improved abrasion resistance and wet skid resistance while a desirable balance of other …
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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 April 29, 1992 and granted February 11, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 29, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 29, 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.