| 摘要 |
<p>PURPOSE: To obtain a coated pigment capable of giving an ink composition having a hydrophilic surface, suppressing peptization, crystal growth and aggregation, high in gloss and coloring power by coating an insoluble azo pigment with a Diels-Alder condensate of an unsaturated multibasic fatty acid with a rosin. CONSTITUTION: This coated pigment capable of giving an aqueous gravure ink high in gloss and coloring power, is obtained by adding sodium hydroxide to a disazo pigment prepared by the coupling of dichlorobenzidine (e.g.; 3,3'- dichlorobenzidine) or tetrachlorobenzidine (e.g.; 2,2', 5,5'-tetrachlorobenzidine) as an azo component with an acetanilide as a coupler component, to make pH10, adding a Diels-Alder condensate (e.g.; maleylated rosin) of an unsaturated polybasic carboxylic acid (e.g.; maleic acid) with a rosin while agitating, heating up to 80 deg.C, then making pH<=5 by 35% hydrochloric acid to coat the pigment surface with the condensate.</p> |
