Process for trash removal or pitch-like resin control in the paper manufacture
CA 2010189 C · Owner: Chemische Fabrik Stockhausen Gmbh · Inventors: Landscheidt, Alfons; Hartan, Georg
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a process for trash removal or pitch control in the paper manufacture in which, process as agent for the trash removal or pitch control cationic groups containing polymers of 50 to 100%-wt. quaternized dimethylaminopropylmethacrylamide or dimethylaminapropylmethacrylamide and 0 to 50%-wt acrylamide acrylic acid, methacrylic acid, acrylamidomethylpropanesulfonic acid, are used, which polymers have an intrinsic viscosity of smaller than 150 ml/g. The trash removal or pitch control agent is added to the pulp flow and/or the circuit water in amounts of up to 1%-wt. relative to the dry weight of the paper manufactured.
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 February 15, 1990 and granted April 17, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 15, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 15, 2012.
- 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.