Process for preparing membranes from tetrahalobisphenol polycarbonates
CA 1321689 C · Owner: Wan, Hawk S. · Inventors: Wan, Hawk S.; Beck, Henry Nelson; Sanders, Edgar S. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention is a process for the preparation of a membrane comprising bisphenol-based polycarbonate wherein at least 25 percent by weight of the bisphenol moieties are tetrahalogenated wherein the halogen is Cl or Br, and the membrane prepared by such process. The process generally requires (1) mixing (i) a bisphenolbased polycarbonate wherein at least 25 percent by weight of the bisphenol moieties are tetrahalogenated wherein the halogen is Cl or Br, and (ii) a solvent for such polycarbonate, wherein the mixture has a sufficient viscosity to allow extrusion at temperatures at which the mixture is homogeneous; (2) heating the mixture to form a homogeneous fluid that is extrudable; (3) …
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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
- Granted August 31, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 31, 2010.
- 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.