Active sizing compositions
CA 2024975 A1 · Owner: Watson, Lawrence F. · Inventors: Watson, Lawrence F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The compositions comprise an aqueous emulsion containing a ketone dimer reactive sizing agent and an anionic dispersant or emulsifier such as sodium lignosulphonate, calcium lignosulphonate or the sodium salt of naphthalene sulphonic acid. In addition an extender or modifier such as an anionic polyacrylamide an anionic starch or colloid silica can be present to extend or modify the anionic charge density of the composition. The compositions are particularly effective in sizing systems containing cationically charged fillers, or cationic additives such as certain retention aids and fluorescent whitening agents.
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 September 10, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended September 10, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 10, 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.