Enhancing brightness and brightness stability of paper containing mechanical pulp
CA 2474713 C · Owner: Ondeo Nalco Company · Inventors: Duggirala, Prasad Y.; Shevchenko, Sergey M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Methods to enhance the brightness and brightness stability of paper and paperboard made with Mechanical Pulp are described and claimed. The method involves applying a Penetrant Compound to paper or paperboard in an amount from about 0.001 percent to about 1 percent by weight. The Penetrant Compound can have one component that is either polyamino polyether methylene phosphonate (PAPEMP) and .alpha.-glucoheptonic-.gamma.-lactone (GL); or the Penetrant Compound can have two components where the first component is , selected from the group consisting of PAPEMP and GL and the second component is an inorganic salt; or the Penetrant Compound can have three components where one component is …
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 January 17, 2003 and granted January 3, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 17, 2023.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 17, 2025.
- 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.