An optical brightener mixture composition, its production and use in cellulosic substrates
CA 2426776 C · Owner: Jackson, Andrew Clive · Inventors: Tindal, Alec Stewart; Farrar, John Martin; Jackson, Andrew Clive
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to an optical brightener mixture (W) comprising optical brighteners , (A) of formula (Ia), and (B) of formula (Ib) and optionally (C) of formula (Ic) as defined , herein, their concentrated aqueous solutions (S) their production and their , use. The optical brightener mixture of the present invention improves and simplifies handling and metering , of water soluble optical brighteners.
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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 January 8, 2002 and granted August 20, 2013. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 8, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 8, 2024.
- 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.