Method for improving quality of deinked high grade waste paper
CA 2098144 A1 · Owner: Fukasawa, Tsuneo · Inventors: Haraga, Hiroyuki; Fukasawa, Tsuneo; Itani, Katsutoshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Quality of deinked/bleached high grade waste paper is improved by bleaching the deinked pulp with thiourea dioxide, said deinked pulp having been obtained by subjecting high grade waste paper to a digesting and aging step with a sulfite, alkali or alkaline peroxide a, disaggregation step, a deinking step and a dust removing step. - 1 7 -
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 June 10, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended June 10, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 10, 2015.
- 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.