Abstract: In the method of manufacturing a disazo pigment according to the present invention, a superior coupling reaction rate during the coupling reaction process makes it possible to manufacture a disazo pigment having superior transparency, brightness, color strength and gloss for the case in which a color strength agent is used. In this method, a coupling reaction is carried out while continuously feeding a coupler aqueous solution comprising a coupler component having the general formula (I) shown below and a tetrazo aqueous solution comprising a benzidine derivative tetrazo component at a molar ratio of 2:0.8.about.0.99 into an acidic aqueous solution held in a batch type mixing vessel. ##STR1## (where each of X, Y, Z independently represents H, CH.sub.3, OCH.sub.

Abstract: The present invention relates to a aqueous pigment paste for an offset ink, which paste is suitable for producing an offset ink by a flushing method, a process for the production of the aqueous pigment paste, and an offset ink obtained by a flushing method. The aqueous pigment paste for an offset ink contains a lake pigment of an azo dye obtained by coupling a diazonium salt of an aromatic amine having a soluble group and a coupler component, 3 to 15% by weight, based on the azo dye, of a rosin, 1 to 20% by weight, based on the azo dye, of a vehicle for an offset ink, the total amount of the lake pigment, the rosin and the vehicle being 10 to 40% by weight, and 60 to 90% by weight of water.

Abstract: A process for the production of a dis-azo pigment which is excellent in sanitary condition and almost free of a residual coupler component and decomposition products derived from the residual coupler component, and has a reduced aromatic amine content, and a dis-azo pigment produced by the said process, the process comprising the steps of (a) coupling-reacting a solution of a tetrazonium salt of benzidine with a slurry of acetoacetanilide of which the amount is stoichiometrically excess relative to an amount of said tetrazonium salt, to prepare a dis-azo pigment slurry, and (b) adding a halogen to the dis-azo pigment slurry to treat the acetoacetanilide in said slurry.

Abstract: A process for the production of a monoazo lake coated with a water-insoluble metal salt of rosin, which comprises the steps of:(a) adjusting a mixed solution containing a monoazo dye having a water-soluble group and an alkali metal or ammonium salt of rosin to pH of 8 to 12, and adding an stoichiometeric amount of a metal salt of at least one metal for insolubilizing rosin selected from the group consisting of zinc, aluminum, copper and manganese to form a water-insoluble rosin metal salt, and(b) adjusting the resultant mixture containing the water-insoluble rosin metal salt to pH of 9 to 12 and adding a metal salt of at least one metal for forming a lake of a monoazo dye selected from the group consisting of calcium, barium and strontium to form a monoazo lake.

Abstract: A monoazo lake which comprises a monoazo dye, a lake-forming metal and a water-insoluble metal salt of a rosin, and which is coated with the water-insoluble water salt of the rosin, the lake-forming metal being at least one metal selected from calcium, barium and strontium, the metal of the water-insoluble metal salt being at least one metal selected from zinc, aluminum, copper and manganese, and a process for the production of a monoazo lake coated with a water-insoluble metal salt of a rosin, which comprises carrying out the following steps (1) and (2) in the order of (1) to (2) or (2) to (1):(1) a step of forming a monoazo lake by forming a lake of a monoazo dye with a metal salt of at least one metal for formation of a lake of the monoazo dye selected from calcium, barium and strontium, and(2) a step of forming the water-insoluble metal salt of the rosin by insolubilizing the rosin with a metal salt of at least one metal for insolubilization of the rosin selected from zinc, aluminum, copper and manganese.