| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a carbon black pigment which excels in water dispersibility and is suited in use for a water base ink. SOLUTION: The carbon black pigment for a water base ink is obtained by subjecting carbon black having a nitrogen adsorption specific area (N2SA) of >=120 m2/g, a DBP absorption of <=80 cm3/100 g, and a tint strength (Tint) of >=120 to oxidation treatment to modify it in such a manner that the amount of hydrogen-containing functional groups in the surfaces of carbon black particles is >=3μmol/m2, and has a ratio of the average particle diameter (Dupa 50%) (nm) of carbon black agglomerate to Stokes, diameter (Dst) (nm) of the carbon black aggregate of 0.8-1.1, an average particle diameter (Dupa 50%) (nm) of the agglomerate of 20-60 (nm), a maximum particle diameter (Duoa 99%) (nm) of the agglomerate of <=160 (nm) and, at the same time, a precipitation residual ratio of <=10 wt.% as the agglomeration properties of particles.</p> |
