Process for the production of paper
CA 2180404 C · Owner: Persson, Michael · Inventors: Carlen, Joakim; Persson, Michael; Johansson, Hans
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for the production of paper from a suspension of cellulose containing fibers and optional fillers, wherein a low molecular weight cationic organic polymer a high molecular weight cationic or ampho- teric polymer and anionic inorganic particles are added to the suspension and the suspension is formed and drained on a wire wherein the low molecular weight polymer has a molecular weight below 700,000 the high molecular weight polymer has a molecular weight above 1,000,000 and said polymers are simul- taneously added to the suspension. The invention further relates to a polymer mixture in the form of an aqueous dispersion comprising at least one high molecular …
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 July 3, 1996 and granted September 17, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 3, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 3, 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.