| 摘要 |
<p>An aqueous carbon black dispersion in which the carbon black has excellent dispersibility in the aqueous medium and which, when used as a water-based black ink such as, e.g., an ink for ink-jet printers, is reduced in feathering and excellent in marring resistance (rapid-drying properties), delivery stability, etc.; and a process for producing the dispersion. The aqueous carbon black dispersion comprises an aqueous medium and, dispersed therein, a carbon black in which hydrogen-containing acid groups present on the surface of the carbon black particles have been neutralized with cations having a valence of 2 or higher and monovalent cations to replace 50-95% of the hydrogen groups of the acid groups with divalent cations and replace the remaining hydrogen groups with monovalent cations. The process for producing the dispersion is characterized by mixing a carbon black with an aqueous solution of an oxidizing agent to oxidize the carbon black in the liquid phase, thereafter removing the salt formed by reduction and contained in the resultant slurry, subsequently adding cations having a valence of 2 or higher and monovalent cations to the slurry to neutralize the carbon black and thereby replace 50-95% of the hydrogen groups in the acid groups with divalent cations and the remaining hydrogen groups with the monovalent cations, and then purifying the carbon black.</p> |
