| 摘要 |
PROBLEM TO BE SOLVED: To obtain a fine carbon powder for electroviscous fluids which is excellent in viscosity response to applied voltage and in dispersion stability by using a carbon black which is obtd. by wet oxidation and has specified permittivity and electric resistivity. SOLUTION: This powder comprises a carbon black which has a permittivity of 3.0 or higher and an electric resistivity of 5Ωcm or higher and is obtd. by the wet oxidation of a carbon black having a Stokes' average mode diameter of aggergates of 170nm or lower. Pref. the carbon black having such charateristics has a water content of 1wt.% or lower. Any carbon black having a Stokes' average mode diameter of aggregates of 170nm or lower can be used as the raw material for this powder without any specific limitation, and any known wet oxidation process can be used. An electroviscous fluid contg. this powder dispersed therein is highly useful as an energy-absorbing material or a vibrationproof material. |
