Strong, air permeable membranes of polytetrafluoroethylene
CA 2233695 C · Owner: Tillmanns, Ralf · Inventors: Burger, Wolfgang; Tillmanns, Ralf; Branca, Phillip A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Microporous membranes are described and characterized as having a morphological microstructure of very highly elongated nodes interconnected by fibrils which form a structural network of voids or pores through the spaces between the nodes and fibrils, which voids or pores extend from one side of the membrane to the other. The membranes are highly uniform in terms of mass per volume, have very high strength and a very open microstructure.
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 August 2, 1996 and granted December 3, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 2, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 2, 2018.
- 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.