Environmentally-friendly fiberline for producing bleached chemical pulp
CA 2327248 A1 · Owner: Stromberg, C. Bertil · Inventors: Stromberg, C. Bertil
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An environmentally friendly (ECF), yet commercially viable process produces , fully, bleached (typically having a brightness of over 89 or 90% ISO) cellulose pulp using a, (ZEND) treatment. Typically pulp is produced in an essentially sulphur-free pulping, process (such as an soda/AQ process) and is then treated by a D-EO-, D-EP-, or D-EOPsequence before the (ZEND) treatment. Optional oxygen delignification may also be used, and subsequent elemental-chlorine-free bleaching sequences may also be employed, although normally not necessary since the pulp after the (ZEND) treatment has high, brightness and good viscosity (e.g. over 21 cP).
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 December 1, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 1, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 1, 2022.
- 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.