Bonded paper pigments
CA 2020207 C · Owner: Raisio Chemicals Canada, Inc. · Inventors: Thorburn, Ian S.; Rattee, Jack A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention pertains to novel bonded pigments used in paper products. A novel composition useful in removing undesirable pitch from the papermaking process and papermaking equipment and fixing the pitch into the paper whilst simulta-, neously improving the optical physical and printability, properties of newsprint and groundwood specialties comprising: (a) a precipitated sodium aluminosilicate having a primary particle size in the range of about 10 to 60 nanometers and, secondary agglomerations of about 1 to 50 microns; and (b) a high molecular weight cationic polyacrylamide polymer having a molecular weight of about 100,000 to about 50,000,000.
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 June 29, 1990 and granted June 25, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 29, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 29, 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.