Asymmetric polymer membrane and preparation thereof
CA 2053743 C · Owner: Anazawa, Takanori · Inventors: Anazawa, Takanori; Sakai, Kazunari; Zhang, Husheng
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is directed to an asymmetric polymer membrane characterized by being formed by irradiating a monomer and/or an oligomer polymerizable with an energy ray and having a pore diameter distribution in the, thickness direction of the membrane a ratio of a permeability flux of oxygen to, nitrogen of 0.9-1.1, and communicating pores.
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 18, 1991 and granted November 20, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 18, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 18, 2013.
- 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.