Quinacridone process
CA 1061344 A · Owner: Harmon Colors Corporation · Inventors: North, Robert J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is provided for the direct production of the gamma crystalline phase of quinacridone. The method comprises ring closing a mixture of dianilinoterephthalic acid and 10 - 20 weight percent of di-(ortho substituted) anilinoterephthalic acid in polyphosphoric acid and thereafter diluting the product with water.
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
- Granted August 28, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 28, 1996.
- 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.