Toyo Ink Manufacturing Company

Hitoshi Sugamo

Yusuke Watabe

Nobuyuki Tomiya

Seiji Aida

Osamu Shiromaru

Yoshimi Kikuchi

Hiroki Nishina

Method of manufacturing a disazo pigment and disazo pigment manufactured

Aqueous pigment paste for offset ink, process for producing the paste,

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.

Process for the production of dis-azo pigment whose amine content is

A process for the production of a monoazo lake coated with a water-insoluble metal salt of rosin, which comprises the steps of:

Process for the production of monoazo lake pigment coated with

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.

Process for production of monoazo lake coated with water-insoluble metal

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Tokyo, Japan

Hitoshi Sugamo