Heat-sensitive recording materials and phenol compounds
CA 2071438 C · Owner: Nakatsuka, Masakatsu · Inventors: Nakatsuka, Masakatsu; Hasegawa, Kiyoharu; Otsuji, Atsuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Heat-sensitive recording materials contain an electron-donating chromogenic compound and an electron-attracting compound. The recording materials also contain at least one compound represented by the following formula:, (see fig. I) or (see fig. II) wherein R1 and R3 mean a hydrogen atom or an alkyl aralkyl or aryl group, R2 and R4 denote an alkyl alkenyl, aralkyl or aryl group, X1, X2 Y1 and Y2 stand, for an oxygen or a sulfur atom and -Z1- and -Z2- are a, specific aromatic group. Also provided are phenol compounds represented by the following formula: (see fig. III), wherein R1, R2, X1 and Y1 have the same meanings as defined above; R5 and R6 are a hydrogen or halogen atom or an alkyl, …
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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 June 17, 1992 and granted April 6, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 17, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 17, 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.