Microporus membrane from cold-rolled precursor films
CA 2007160 C · Owner: Gillberg-Laforce, Gunilla E. · Inventors: Gillberg-Laforce, Gunilla E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The process for forming a microporous polymeric semi-crystalline film, involving the steps of cold compressive extruding a precursor film, preferably in a biaxial fashion so, as to compress the film by a factor of about 2 to 1 to about 10 to 1, stretching the film by about 100 to about 500 percent preferably in a biaxial fashion, and heat annealing either before, during; or preferably after the stretching step at a temperature up to the alpha transition temperature of the polymer for a time sufficient to maintain the microporous character of the final film.
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 January 4, 1990 and granted August 19, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 4, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 4, 2012.
- 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.