PIGMENT DISPERSION AND PRINTING INK

摘要

PURPOSE:To obtain a printing ink or a coating material which has a low viscosity with less variation with time and excellent gloss and clearness of the film by adding a metallic salt of an aromatic hydroxycarboxylic acid to a soluble azo pigment. CONSTITUTION:100 pts.wt soluble azo pigment (e.g. a hydroxy-naphthoate azo lake pigment or Watchung red) and 0.5-20 pts.wt metallic salt of an aromatic hydroxycarboxylic acid (e.g. a strontium salt of 2-hydroxy-3-naphthoic acid) are added to an ink composition or coating composition consisting of a soluble azo pigment, a resin (e.g. acrylic resin) and a solvent (e.g. water or isopropyl alcohol) before, during or after milling. The printing ink thus prepared is particularly suitable for use as a gravure ink or flexographic ink in high-speed printing.