PRODUCTION OF INK FOR INK JET RECORDING

摘要

PROBLEM TO BE SOLVED: To obtain a process for producing an ink for ink jet recording whereby a pigment can be dispersed with an improved dispersibility into particles with uniform particle sizes by subjecting a pigment dispersion to ultrasonic treatment at specified output and frequency. SOLUTION: A pigment dispersion contg. a pigment, a polymeric dispersant, a water-soluble solvent, and water is subjected to ultrasonic treatment at an output of 250-3,000W and a frequency of 20-50kHz to disperse the pigment. The polymeric dispersant used id pref. a (meth)acrylic acid deriv. copolymer, esp, one obtd. by copolymerizing a monomer represented by formula I (R1 and R2 are each H or lower alkyl; m1 is 0-2; AO is 2-3C oxyalkylene; n is 1-300; and X is H or lower alkyl) and a monomer (including its acid anhydride) represented by formula II [R3 to R5 are each H, lower alkyl, or (CH2 )m2 COOM2 (wherein M1 and M2 are each H, an alkali or alkaline earth metal, ammonium, or an amine, and m2 is 0-2].