| 摘要 |
PROBLEM TO BE SOLVED: To obtain a carbon black having high insulating properties by subjecting a carbon black obtained by a contact method to an oxidation treatment with an oxidizing agent containing ozone and/or hydrogen peroxide. SOLUTION: This carbon black has a powder resistance of 10Ω.cm or more, a value, obtained by dividing its volatile component by its specific surface area, of 0.09%/m<2> or more, a DBP absorption amount of 100-300 ml/100 g and a specific surface area of 90-1,100 m<2> /g. An oxidation treatment is carried out by putting carbon black in a stainless kiln and bringing it into contact with ozone, thus an oxygen-containing functional group is introduced into a surface of the carbon black. The temperature of the atmosphere is not particularly limited and is preferably 50-150 deg.C. A preferable oxidative other than ozone is hydrogen peroxide. The amount of an ash of the carbon black used for the oxidation treatment is preferably 1% or less. The major components of the ash are an alkali metal and an alkaline earth metal such as Na, K and Ca, which are necessary to be reduced.
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