Microporous polyolefin membrane and method of producing same
CA 2025520 C · Owner: Kono, Koichi · Inventors: Okamoto, Kenkichi; Takashima, Tatsuya; Takita, Kotaro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A microporous polyolefin membrane made of a polyolefin composition containing 1 weight % or more of an ultra-high-molecular-weight polyolefin having a weight-average molecular weight of 7 x 10 5 or more and having a weight-average molecular weight/number-average molecular weight ratio of 10-300, the microporous membrane having a thickness of 0.1-25 µm, a porosity of 35-95%, an average pore diameter of 0.001-0.2 µm and a breaking strength of 0.2 kg or more per 15 mm width is produced by (a) preparing a solution comprising 10-50 weight % of the polyolefin composition and 50-90 weight % of a solvent; (b) extruding the solution through a die; (c) cooling the extruded solution to form a …
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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
- Filed September 17, 1990 and granted May 29, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 17, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 17, 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
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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.