Paper coating composition with improved optical brighteners carriers
CA 2370175 A1 · Owner: Hercules Incorporated · Inventors: Bock, Eric F.; Walsh, L. Drake; Burdick, Charles L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A paper coating composition has therein an optical brightening agent (OBA) and a water-soluble non-ionic polysaccharide derivative exhibiting a solution , viscosity in water of less than 1500 cps when dissolved at 5% polymer concentration, wherein the paper coating provides improved optical brightness as compared to the same formulation without said non-ionic polysaccharide , derivative. A paper coated with this composition has an optical brightness value of greater than 70.
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 April 27, 2000. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 27, 2020.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 27, 2022.
- 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.