The easy water dispersible carbon black and its production mannered

摘要

PROBLEM TO BE SOLVED: To obtain a carbon black which is easily dispersible in water and is useful as a pigment for an aq. black ink, etc., by dry grinding a carbon black having specified physical properties to crack agglomerates and subjecting the carbon black to oxidation. ;SOLUTION: A carbon black having a nitrogen-adsorption specific surface area (N₂SA) of 50 m²/g or higher and a DBP oil absorption of 80 ml/100 g or lower is dry ground to crack agglomerates to a Dupa 50%/Dst of 1.1-1.5, a Dupa 50% of 40-140 nm, and a Dupa 99% of 25 nm or lower and then is oxidized to such a state that the sum of carboxyl and hydroxyl groups, among hydrogen-contg. functional groups formed on the surface of the carbon black particle, per unit area is 3 μeq/m² or higher. Dst is a Stokes' mode diameter (nm) of aggregate; Dupa 50% is the value of 50% cummulative frequency in the cummulative frequency distribution curve of agglomerate particle size; and Dupa 99% is the value of 99% cummulative frequency.;COPYRIGHT: (C)1999,JPO