| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an aqueous dispersion of oxidized carbon black useful for aqueous black ink for use in a inkjet printer and aqueous ink. <P>SOLUTION: This aqueous dispersion of the oxidized carbon black is made by liquid-phase oxidation of carbon black with a peroxo diacid or peroxo diacid salt so as to be 2-5μmol/m<SP>2</SP>of a carboxyl group, neutralization of some or all of the carboxyl groups of the carbon black with an alkali solution of a dissociation constant (pKa) of 5 or less, and then a removal of a residual salt and purification, wherein the aqueous dispersion of the oxidized carbon black is classified so that, in the carbon black particle aggregate, an average particle diameter Dupa 50% is 50-130 nm, a maximum particle diameter Dupa 99% is 150-320 nm, and value ofΔDupa (mode)/Dupa (mode), the ratio of a half-band width in a particle size distributionΔDupa (mode) to a mode diameter Dupa (mode), is 1.20 or less, and it is made by adjusting pH of the aqueous dispersion 4-6 and adding 1-6 wt.% (based on the carbon black) of a polyethyleneimine having a molecular weight of 200-1,000. <P>COPYRIGHT: (C)2003,JPO</p> |
