Method for producing electret filter
CA 2067925 A1 · Owner: Mitsui Petrochemical Industries, Ltd. · Inventors: Matsuura, Satoshi; Shinagawa, Yoshio; Yokoyama, Akira
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A highly efficient reliable method is provided for, producing an electret filter having an excellent collection efficiency. The method comprises the steps of forming a film comprising a high molecular weight compound splitting, the film to form split yarns subjecting the split yarns to, a homo charging and producing the electret filter from the charged split yarns.
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 May 1, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 1, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 1, 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.