New findings on the dispersion process and change in tinting strength [Review]

摘要

Previous work has shown that the dispersion process can be described quantitatively by three processes - size reduction against large particles, small particles and the vessel walls/grinding bodies. However, the equation developed was unsatisfactory in two respects. Not all the dispersion rate constants could be determined and only two measured values were used for the equation. This paper briefly describes and explains the previous results. It will then be shown how a curve fitting can be achieved using all the measured values. The second objective of determining the three dispersion rate constants requires the use of a second mill base with a different total pvc. Section 2.2 verifies the new process using two transparent iron oxide red pigments. It can be seen that the correlation of the curves obtained using the experimental measured values is remarkably good. What is surprising is the finding that the dispersion rate constant for the size reduction against the vessel walls/grinding bodies is negative which indicates that it is not reduction which takes place but reagglomeration. The new process requires at most a second mill base with a different total pvc and the programming of a computer. It provides an interesting insight into the grinding and dispersion behaviour of pigments and is suitable for varying grinding processes selectively. (C) 1998 Elsevier Science S.A. All rights reserved. [References: 4]