Production of paper, paperboard and cardboard with two-component polymeric retention aid
CA 2576611 C · Owner: Leifert, Peter · Inventors: Leduc, Marc; Leifert, Peter; Blum, Rainer
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 the production of paper paperboard and , cardboard by dripping a paper material onto a sieve by forming sheets and , then drying the sheets. The sheets are formed in the absence of fineparticled, inorganic, flocculating agents and the retention agent is used as (a) polymers containing vinylamine units and/or polyvinylformamide having a molar mass Mw of, respectively, at least 1 million and (b) at least one cationic or non-ionic polyacrylamide and/or a cationic or non-ionic polymethacrylamide having a molar mass Mw of respectively, at least 2.5 , million.
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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 September 8, 2005 and granted December 23, 2014. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 8, 2025.
- Certificates of supplementary protection extend only drug patents, and it isn't classified as one.
- 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.