Novel methods for synthesizing polyvinyl amine (pva) type flocculating and coagulating agents, novel agents thus obtained, uses thereof and improved paper types thus obtained
CA 2365347 C · Owner: Jehn-Rendu, Christian · Inventors: Jehn-Rendu, Christian; Hund, Rene
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 method for synthesizing polyvinylamine (PVA)- type polymers from a vinylformamide monomer at a low temperature. According to the invention polymerization starts at 0 ·C, is initiated by an original redox and azoic catalyst combination and is carried out at a substantially normal pressure.The polymerisation is conducted in water and is followed by direct hydrolysis. A cationic PVA is obtained directly in the form of a powder with a high molecular weight. It is also possible to operate with an emulsion at an initiation temperature of approximately 15 %. The PVA can be used as flocculating and coagulating agents in the paper industry water treatment industry, oil …
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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 9, 2000 and granted May 31, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 9, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 9, 2022.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.