Process for the preparation of organophilic prussian blue pigments

摘要

Organophilic prussian blue pigments easily dispersible in the dry state in organic media are prepared by mixing an aqueous suspension of the prussian blue with a solution of an alkali metal or ammonium salt of a fatty acid, preferably having 16-18 carbon atoms, and may contain a hydroxy group, for example ricinoleic acid, or it may be a salt of industrial stearine, containing stearic, oleic and palmitic acids, or a salt of a partially polymerized unsaturated fatty acid, adding to the mixture a salt capable of forming a precipitate with ferrocyanide ions, for example a ferric salt such as the chloride or a zinc salt such as the sulphate, separating the prussian blue, drying and disintegrating. The product may be dispersed in lacquers having slightly polar or non-polar character such as oil modified alkyd resins, solutions of epoxy resins esterified with fatty acids, oil varnishes, or oleoresinous varnishes, or in organic media of polar character, for example alcohols, ketones, esters, and in vehicles of similar character, for example nitro-cellulose lacquers, spirit varnishes, alkyl urea-formaldehyde vehicles, alkyl melamine-formaldehyde vehicles, amino formaldehyde epoxides and phenol-formaldehyde epoxides.