Tapered block copolymers of monovinylarenes and conjugated dienes
CA 2134026 C · Owner: Farrar, Ralph C. Jr. · Inventors: Farrar, Ralph C. Jr.; Moczygemba, George A.; Stacy, Nathan E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for preparing tapered block copolymers which are particularly useful for blend components in blends with polymers of styrene. In the first embodiment of this invention the copolymers are prepared in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic monomers in the presence of a randomizer; (2) an initiator and monovinylaromatic monomers; (3) a mixture of monovinylaromatic and conjugated diene monomers; and (4) a coupling agent; to produce a polymodal tapered block copolymer. In a second embodiment of the invention tapered block copolymers are prepared in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic …
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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 October 21, 1994 and granted June 9, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 21, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 21, 2016.
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