Tapered block copolymers of monovinylarenes and conjugated dienes
CA 2134027 C · Owner: Stacy, Nathan E. · Inventors: Moczygemba, George A.; Knight, Nancy R.; Trepka, William J.
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 in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic monomer in the presence of a randomizer; (2) an initiator and monovinylaromatic monomer; (3) a mixture of monovinylaromatic and conjugated diene monomers; (4) a mixture of monovinylaromatic and conjugated diene monomers; (5) conjugated diene monomer; and (6) a coupling agent; and the polymodal tapered block copolymers prepared thereby. The copolymers are particularly useful neat or in blends for applications such as packaging and food or drink containers which require transparency and good environmental stress crack resistance.
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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 October 13, 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.
- 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
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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.