Method of manufacturing a disazo pigment and disazo pigment manufactured thereby

PCT No. PCT/JP97/00547 Sec. 371 Date Oct. 24, 1997 Sec. 102(e) Date Oct. 24, 1997 PCT Filed Feb. 26, 1997 PCT Pub. No. WO97/31067 PCT Pub. Date Aug. 28, 1997In 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 DIFFERENCE 0.99 into an acidic aqueous solution held in a batch type mixing vessel. (where each of X, Y, Z independently represents H, CH3, OCH3, Cl)