Method for producing pulp and paper with calcium carbonate filler
CA 2324459 A1 · Owner: Desmeules, Josee · Inventors: Desmeules, Josee; Middleton, Steven R.; Scallan, Anthony M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is described for attaining high levels of loading of calcium carbonate fillers in the lumens of wood pulp fibres. The pulp is pretreated with a cationic polymer prior to being impregnated with the filler. Different conditions of pH and temperature are specified depending on whether the filler is a precipitated calcium carbonate or a ground calcium carbonate. The lumenloaded pulps are used to make novel products with advantages in higher filler retention and sheet strength over conventionally made papers.
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 March 17, 1999. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 17, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 17, 2021.
- 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.