Process for making azo-pigments
CA 2063430 C · Owner: Clariant Gmbh · Inventors: Rieper, Wolfgang
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The production which is customary in practice of monoazo compounds based on dichloro- and trichloroanilines or disazo compounds of the chlorinated biphenyl series by conventional coupling methods meets with difficulties in that the resulting pigments are contaminated by traces of polychlorinated biphenyls. According to the invention, it has now been found that by addition of water-soluble olefins of the type (see above formula), (R=H, C1-C4-alk or C1-C4-Oalk; X = -COOR1 -CONHR2,or -NR3COR4, wherein R1 is hydrogen or optionally substituted C1-C4-alkyl R2, is hydrogen or optionally substituted C1-C4-alkyl R3 is, hydrogen or C1-C4-alkyl and R4 is C1-C4-alkyl) in the azo coupling, the side …
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 June 16, 1990 and granted August 1, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 16, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 16, 2012.
- 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.