GB771678A - Flushing pigments - Google Patents

Abstract

A flushed pigment is prepared in powder form by a method which includes adding to an aqueous dispersion or solution of a diazo component or of a coupling component of an azo pigment or to both, or to an aqueous solution or dispersion of any other compound which is subsequently converted to form a pigment dye, a flushing agent comprising an organic solution of a tall oil, a natural or synthetic resin or rosin or a salt, ester or other derivative thereof, before forming and precipitating the pigment. The flushing agents include hydrogenated tall oil, alkyd resins, or resinic acid, rosin or tall oil esterified with monovalent or polyvalent alcohols, e.g. ethanol, penta-erythritol, glycerol, trimethylol propane or hexanetriol, and may be dissolved in solvents such as wood turpentine oil, white spirit, benzine, benzene, toluene, chlorobenzene, trichloroethylene, perchloroethylene and higher alcohols, esters and ketones. Antioxidants, e.g. butylphenol may be added. In examples, b -naphthol is dissolved in water with the addition of sodium hydroxide and carbonate solutions, and a solution of glycerol ester gum introduced with the addition of sodium rosin soap. The resulting emulsion is coupled with the diazo compound obtained from m-nitro-p-toluidine, when a well-filtrable precipitate is formed, which is dried and ground. The glycerol ester gum solution may alternatively be added to the diazo solution before coupling in the presence of an emulsifier, e.g. ethoxylated rosin.ALSO:A flushed pigment is prepared in powder form by a method which includes adding to an aqueous dispersion or solution of a diazo component or of a coupling component of an azo pigment or to both, or to an aqueous solution or dispersion of any other compound which is subsequently converted to form a pigment dye, a flushing agent comprising an organic solution of a tall oil, a natural or synthetic resin or rosin or a salt, ester or other derivative thereof, before forming and precipitating the pigment. The flushing agents include hydrogenated tall oil, alkyd resins, or resinic acid, rosin or tall oil esterified with monovalent or polyvalent alcohols, e.g. ethanol, penta-erythritol, glycerol, trimethylol propane or hexanetriol, and may be dissolved in solvents such as wood turpentine oil, white spirit, benzine, benzene, toluene, chlorobenzine, trichloroethylene, perchloroethylene and higher alcohols, esters and ketones. Antioxidants, e.g. butylphenol may be added. In examples, b -naphthol is dissolved in water with the addition of sodium hydroxide and carbonate solutions, and a solution of glycerol ester gum introduced with the addition of sodium rosin soap. The resulting emulsion is coupled with the diazo compound obtained from m-nitro-p-toluidine, when a well-filtrable precipitate is formed, which is dried and ground. The glycerol ester gum solution may alternatively be added to the diazo solution before coupling in the presence of an emulsifier, e.g. ethoxylated rosin.