Filter cigarette
CA 2234795 C · Owner: Willmund, Rolf · Inventors: Willmund, Rolf; Teufel, Eberhard; Sexauer, Wolfgang
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a filter cigarette whose filter a) contains fibrous filter material, b) contains an additive with antimutagenic effects on the cigarette smoke in a quantity equivalent to less than 15 wt % of the weight of fibre and c) during test smoking of an unventilated filter cigarette of this type but containing no additive has a nicotine retention R , N (in %, determined according to CORESTA recommended, method no. 9) which satisfies the following formula: R N <= 100 * (1-D) in which D = exp (A * B + C), A being 21 mm - filter length (mm) for filter lengths <= 25 mm or A being -4 mm for filter lengths > 25 mm, B being 9.3 * 10-3 (1/mm) and C being -(d4 * .DELTA.p * K + L) with d = …
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 October 31, 1996 and granted April 30, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 31, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 31, 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.