Porous semipermeable membrane resistant to chemicals and heat
CA 2061990 A1 · Owner: Cherdron, Harald · Inventors: Schneider, Juergen; Krieg, Claus-Peter; Cherdron, Harald
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Porous semipermeable membrane resistant to chemicals and heat, A semipermeable membrane for micronano- and ultra-, filtration, comprising a carrier material and a semipermeable layer adhering to this. The carrier material is a woven fabric or a non-woven based on a polyphenylene sulfide, a polyether ketone or a polyaramid. To produce the semipermeable membrane, the polymers are first dissolved in a solvent and the solution is filtered and degassed. In a subsequent step, a membrane is produced by the phase inversion process, H2SO4, CF3-SO3H HF, Cl2HC-COOH or a mixture of Cl2HC-COOH and H2SO4 being employed as the solvent for polyether ketones and N-methylpyrrolidone, dimethylacetamide or …
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 February 27, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 27, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 27, 2014.
- 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.