Toyo Ink Manufacturing Company

Masatoshi Momose

Mikio Hayashi

Shigeki Kato

Hitoshi Maki

Shinichi Azuma

Hideko Noguchi

A process for the production of a phthalocyanine pigment having a clear color tone, a high tinting strength and a finely milled structure by an efficient and economical process, in which the pigmentation from a phthalocyanine crude can be carried out without removing an aromatic hydrocarbon solvent used in the synthesis of the phthalocyanine crude, the process comprising thes steps of (a) reacting phthalic anhydride or its derivative, urea or its derivative and a catalyst in an organic solvent to synthesize a phthalocyanine crude, (b) wet-milling a slurry of the synthesized phthalocyanine crude in the presence of a milling medium without removing the aromatic hydrocarbon solvent, and (c) removing the organic solvent from the slurry of the milled product, purifying the milled product and drying the milled product with a spray type dryer.

Process for the production of phthalocyanine pigment

A process for producing highly pure 6,13-dihydroquinacridone, which is a suitable intermediate for effectively producing a quinacridone pigment, for a short period of time at high yields, the process comprising providing a cylindrical reactor, providing an atmosphere free of oxygen in the cylindrical reactor, heating the cylindrical reactor so that the temperature of at least a surface of an inner wall of a cylinder of the cylindrical reactor is in the range of from 250.degree. to 400.degree. C., introducing a powder of 2,5-di(arylamino)-3,6-dihydroterephthalic acid dialkyl ester or a mixture of 2,5-di(arylamino)-3,6-dihydroterephthalic acid dialkyl ester with a liquid through a feed port provided in an upper portion of the cylindrical reactor, keeping the powder or the mixture in substantial contact with the inner wall of the cylindrical reactor so that an intramolecular alcohol-elimination reaction of the 2,5-di(arylamino)-3,6-dihydroterephthalic acid dialkyl ester takes place to form 6,13-dihydroquinacridone, and taking out the 6,13-dihydroquinacridone through an outlet provided in a lower portion of the cylindrical reactor.

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Tokyo, Japan

Masatoshi Momose