Stabilized, aqueous hydrazide solutions for photographic elements
CA 2065573 A1 · Owner: Fodor, Ludovic · Inventors: Fodor, Ludovic
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for stabilizing aqueous solutions of aryl hydrazides is described. These solutions may be made by the addition of a stabilizing amount of ascorbic acid isoascorbic acid, erythorbic acid, tartaric acid citric, acid, glucose and a cyclodextrin etc. or mixtures, for, example. When aqueous solutions of aryl hydrazides containing these stabilizers/antioxidants are prepares the solution will have a shelf life of up to 30 days compared to 1-3 hours of solutions without the stabilizer/antioxidant. The stabilized aryl hydrazide is useful in photographic silver halide emulsions etc.
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 8, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 8, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 8, 2014.
- 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.