PREPARATION OF DISAZO PIGMENT COMPOSITION

摘要

PROBLEM TO BE SOLVED: To provide disazo pigment compositions which provide excellent dispersibility as an offset ink. SOLUTION: A method for preparing a disazo pigment composition comprises introducing a tetrazo solution of a benzidine into a weakly acidic aqueous slurry in which coupler particles composed of an acetoacetanilide and a printing ink varnish have been dispersed with stirring or simultaneously introducing a printing ink varnish and a tetrazo solution of a benzidine into a weakly acidic aqueous slurry in which coupler particles composed of an acetoacetanilde have been dispersed with stirring to effect coupling reaction.