In cases where the quality of dispersion does not meet the required standard, the following parameters should be checked:
Duration of the dispersion operation
The quality of formulations dispersed using a DISPERMAT® with a sufficient high‒speed generally reaches its final value after a short period of time (approximately 10 ‒15 minutes). Increasing the dispersion time to more than 20 minutes does not normally lead to improved results.
The doughnut flow pattern should be maintained during the course of the whole dispersion.
The mechanical power input should be optimised by using the highest possible shaft speed whilst considering the tip speed in m/sec of the dissolver disc, without destroying the doughnut flow pattern.
The distance between the dissolver disc and the bottom of the vessel can be changed to obtain better results and to make higher rotational speeds possible.
Amount of millbase
Better flow characteristics may be achieved by using more or less millbase in the container.
When dispersing, high energy transfer into the millbase will lead to an increase in temperature. In many cases this destroys the flow characteristics of the formulation. In addition, thermally sensitive paint ingredients may be harmed. Using a water cooled vessel will solve the problem.
Partial re‒formulation of the paint using more suitable resins, pigments, fillers or additives: It should be kept in mind, that the DISPERMAT® is a dispersion device and not a piece of milling machinery. Therefore it is incapable of grinding primary particles down to a smaller size.
At a dispersion under vacuum high‒viscous products can be produced to the greatest possible extend without air bubble inclusions.