| 摘要 |
PROBLEM TO BE SOLVED: To provide an aqueous dispersion of an oxidated carbon black which is suitable as black aqueous ink e.g. an inkjet printer or aqueous ink. SOLUTION: This aqueous dispersion of an oxidated carbon black is prepared by subjecting a carbon black having a CTAB specific surface area (10<SP>3</SP>m<SP>2</SP>/kg) and a DBP absorption (10<SP>-5</SP>m<SP>3</SP>/kg) satisfying the relations represented by CTAB×DBP<185 (m<SP>5</SP>/kg) and 5 (nm)<DBP/CTAB<12 (nm) to liquid-phase oxidation with a peroxo diacid or its salt to generate 2-5μmol/m<SP>2</SP>carboxyl groups, neutralizing at least a part of the carboxyl groups with an alkali solution having a dissociation constant (pKa) lower than 5, eliminating the remaining salt, subjecting thus treated carbon black to a classification treatment so as to give a carbon black of which the particle aggregates in the dispersed state in water have an average particle size Dupa 50% of 50-130 nm, a maximum particle size Dupa 99% of 150-320 nm, and a ratioΔDupa (mode)/Dupa (mode) of the half-value widthΔDupa (mode) of the particle distribution to the mode diameter Dupa (mode) of 1.20 or lower, and dispersing the resultant carbon black in an aqueous dispersion medium. COPYRIGHT: (C)2003,JPO
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