Copolymers of 4-hydroxystyrene and alkyl substituted-4-hydroxystyrene
CA 2000710 A1 · Owner: Hinsberg, William D. Iii · Inventors: Vicari, Richard; Mckean, Dennis R.; Willson, Carlton G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A copolymer of (a) an unsubstituted 4-hydroxystyrene monomer and (b) a substituted 4-hydroxystyrene monomer of the formula wherein A, B, C, and D are independently H or C1 to C3 alkyl and wherein at least one of A, B, C and D is C1 to C3 alkyl; and wherein said copolymer has a molecular weight of from about 800 to about 100,000; and wherein the mol ratio of monomer (a) to monomer (b) ranges from about 3:1 to about 1:3.
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 October 13, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 13, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 13, 2011.
- 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.