Cyan dye-forming couplers and photographic materials containing same
CA 1305349 C · Owner: Kilminster, Kenneth N. · Inventors: Hoke, David; Kilminster, Kenneth N.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract, Novel phenolic cyan dye-forming couplers contain a p-cyanophenylureido group in the 2position and in the 5-position an acylamino substituent containing a sulfone group having bulky substituents sufficient to provide steric interaction within the coupler molecule and the dye molecule derived therefrom. The couplers are represented by the formula:, wherein:, R1, R2, R3 and Z are as defined in the specification. The couplers are useful in photographic emulsion.
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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
- Granted July 21, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 21, 2009.
- 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
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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.