| 摘要 |
PROBLEM TO BE SOLVED: To provide a carbon black pigment having excellent dispersion performance into water and suitable for a water-based black ink. SOLUTION: The carbon black pigment for a water-based ink has an atomic ratio (the intensity of oxygen bonding energy/that of carbon bonding energy) of the entire oxygen atoms to the entire carbon atoms, measured by X-ray photoelectron spectroscopy, of >=0.1 by chemically modifying carbon black having a nitrogen adsorption specific area (N2SA) of 200-270 m2/g, an iodine adsorption amount (IA) of 190-260 mg/g, a ratio of N2SA to IA of 0.96-1.20, a CTAB specific area of 170-240 m2/g, a DBP absorption amount of 100-150 cm3/100 g, a 24M4DBP absorption amount of 90-120 cm3/100 g, and a Tint of >=135. Furthermore, the carbon black pigment has particle properties such that the modal diameter Dst of a stokes diameter distribution of an aggregate is 30-60 nm; the half widthΔDst in the distribution is <=60 nm; the Dupa 50% value of the average particle diameter of an agglomerate is 60-110 nm; and the Dupa 99% value of the maximum diameter of the agglomerate is <=210 nm. |
