Method of determining the liquid absorption of pulverulent solids

摘要

The liquid absorption of pulverulent solids is, for example, measured as "DBP number" in the case of carbon black (by the Cabot method) or as "oil number" in the case of pigments and fillers. The known methods give results which are only moderately reproducible when the bulk density of the powder is extremely low. The new process can be used in a wide range of bulk density of the powder. The powder particles are only slightly stressed mechanically. Agglomeration of the particles is avoided. The powder is stirred in a planetary mixer and fluidised. The liquid to be absorbed is optionally preheated and conveyed continuously (without pulses) to the application device and is there atomised. From the measured course over time of the torque at the stirrer motor, various parameters are taken from which the liquid absorption is calculated. The new process can be used on powders having a bulk density of from 0.05 to 3 g/cm<3>. The absorption of ethylene glycol or dibutyl phthalate by active silica, carbon black or light-coloured fillers was measured.