抄録
Equipment for measuring the wettability (i. e. the contact angle) of hydrophobic powder was newly developed, based upon the so-called constant flow method. This equipment has a feature in which the specific surface area of the powder, the threshold pressure at which a liquid begins to penetrate the powder bed and its contact angle are calculated and printed out. This happens when the values related to the operational conditions and the physical properties of air, liquid and powder used in the measurement are put in advance into the computer installed in this equipment.
The availability of this equipment was confirmed by investigating the effect of operational factors such as the feed rate of pure water, the porosity of the powder bed and its height on the contact angle of aluminum hydroxide powder treated with stearic acid. The relationship between the contact angle of the sample powder and the concentration of stearic acid, the mixing time, the dispersion state in pure water or the amount of DOP (dioctyl phthalate) absorbed was also obtained.
