| 摘要 |
PURPOSE:To obtain the titled carbon black which is high in S/N and excellent in a long-term stability and provides no damage to recording matrix, by specify ing an average particle diameter of a prim. particle, a DBP absorption and an alkaline earth metal content. CONSTITUTION:A raw material comprising an acetylene gas or an unsatd. hydrocarbon-contg. acetylene gas is pyrolytically decomposed with a mixed gas contg. O2 and steam to obtain a carbon black for electrostatic capacity type of information recording medium having an average particle diameter of 200nm or less in terms of prim. particle, DBP absorption of 200ml/100g or less as determined according to JIS-K-6221, an alkaline earth metal content of 200ppm or less. 100pts.wt. thermoplastic resin (e.g.: PVC) is incorporated with 15-40pts.wt. carbon black, 3pts.wt. or less lubricant (e.g.: liquid paraffin), 3pts.wt. or less slip agent (e.g.: ester wax), 5pts.wt. stabilizer (e.g.: dibutylin laurate), 5pts.wt. or less auxiliary stabilizer (e.g.: epoxylator), etc., and the product is formed into a desired shape to obtain a recording medium.
|
