Phenolic compounds
CA 2046687 A1 · Owner: Shimada, Akira · Inventors: Minami, Toshiaki; Shimada, Akira; Kinishi, Ryoichi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
4-Hydroxydiphenylsulfone derivatives represented by formula (I), (I), wherein R1, R2, R3 and R4, independently from one another, each denote a hydrogen atom, an alkyl group, a substituted or unsubstituted phenyl group or a cycloalkyl group, provided at least one of R1, R2, R3 and R4 is other than a hydrogen atom, and, R denotes an alkyl group an alkenyl group, a, substituted or unsubstituted phenyl group a, substituted or unsubstituted cycloalkyl group or a substituted or unsubstituted phenylalkyl group. Said compounds are useful as a developer in a heat sensitive color formation layer of a heat sensitive recording material.
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 July 10, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 10, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 10, 2013.
- 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.