SURFACE-MODIFIED CARBON BLACK AND PRODUCTION THEREOF

PURPOSE:To provide a surface-modified carbon black capable of securing a uniform dispersion stability irrespective of an acidic formulation or a basic formulation and a process for producing the same. CONSTITUTION:A surface-modified carbon black has such a surface compsn. of functional groups that the molar ratio of hydroxyl groups introduced into the surface of carbon black to quinone groups is at least 10. The process for producing the surface-modified carbon black is as follows. Carbon black is treated with an oxidizing agent containing, if necessary, sulfur to sulfonate the surface of the carbon black, followed by filtration and drying. The resulting carbon black residue is fused by using a basic flux, cooled, and neutralized with an acid, followed by washing with water and drying.