Sulfam(na)phthaleins
CA 1109068 A · Owner: Polaroid Corporation · Inventors: Ellis, Ernest W.; Foley, James W.; Borror, Alan L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to 1-naphthol sulfam(na)phthaleins possessing a carbonyl moiety on the N atom of sulfam(na)phthalein ring, which compounds find utility for, example, as antihalation and filter dyes in photographic products and processes.
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
- Granted September 15, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 15, 1998.
- 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.