| 摘要 |
PROBLEM TO BE SOLVED: To obtain a carbon black good in dispersibility even when using a mineral oil with a low content of polycyclic aromatic components, good in fluidity and printability when converted into an ink and reduced in blots by specifying the particle diameter, the specific surface area and the range of pH. SOLUTION: The particle diameter of a carbon black is regulated to 32-52 nm and the specific surface area thereof is regulated to 40-80 m<2> /g. The pH is further regulated to <=2.9. The volatile content is preferably >=1.3% and the iodine adsorption amount is preferably 20-60 mg/g. The DBP oil absorption volume is preferably 30-100 cm<3> /100 g and the amount of the total acidic groups is preferably >=0.5 μequ<2> . The carbon black can be prepared in a furnace type oven. A fuel is burned with an oxygen-containing gas to produce a high- temperature gas and an aromatic hydrocarbon to be a raw material is introduced into the high-temperature gas to produce the carbon black by incomplete combustion. The resultant carbon black-containing gas is then cooled with water, etc., to stop the reaction. Furthermore, an oxidizing agent such as nitric acid or ozone is used to carry out an oxidation treatment. |
