Filter tow, method for the production thereof, as well as tobacco smoke filter element and method for its production
CA 2124414 C · Owner: Willmund, Rolf · Inventors: Willmund, Rolf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A filter tow from cellulose acetate filaments and/or staple fibers is described on the surface of which an additive from cellulose chain-splitting enzymes is present at least, the surface of the filaments and staple fibers consisting of a cellulose acetate having an acetyl number of less than 53% preferably less than 49%. The method for the production of such a filter tow comprises spinning cellulose acetate filaments from a solution in acetone, of cellulose acetate of an acetyl number of at least 53% if necessary, cutting the filaments to staple fibers, gathering the filaments and/or staple fibers to a filter tow and applying an additive, the filaments and staple fibers being hydrolyzed …
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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 May 26, 1994 and granted April 8, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 26, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 26, 2016.
- 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.