Production of azomethine pigment

Abstract From the Canadian patent

Process for the production of a compound of formula in pigmentary form having a mean particle size not exceeding 2.0 microns, comprising, a) first reacting together 2-hydroxy-1-napthaldehyde and 2-aminophenol under aqueous alkaline non-oxidising conditions, and either neutralising the reaction product or isolating the reaction product and re-dispersing it in aqueous medium and adding to the neutralized or redispersed reaction production whilst applying mechanical stirring to the mixture, an aqueous solution of a coppering agent, b) separating the solid product washing it free from inor-, ganic salts and optionally drying it and, c) subjecting the dried pigmentary product to a kneading …