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Abstract

The present invention provides a carbon black coloring agent suitable as a black coloring agent for a semiconductor sealing material, exhibiting excellent dispersibility in a resin component, and capable of forming a semiconductor sealing material having a high volume resistivity and excellent shading properties, and a method of manufacturing the same. The carbon black coloring agent has a structure in which terminal hydrogen of a carboxyl group formed on the surface of a carbon black particle by wet oxidation using sodium persulfate or ammonium persulfate is replaced by ammonia, and has a pH of 3.0 to 8.0. The method includes subjecting carbon black to wet oxidation in a sodium persulfate aqueous solution or an ammonium persulfate aqueous solution, removing reducing salts by deionization, adding an ammonia aqueous solution reaction to adjust the pH of the slurry to 4.0 to 12.0, causing the carbon black to react with ammonia, purifying the slurry by removing foreign matter from the slurry, and drying and grinding the carbon black. It is preferable to subject the carbon black to dry oxidation in advance before wet oxidation and to add a surfactant when subjecting the carbon black to wet oxidation.

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First Claim