Scale-up

Considering the many influences on the spatial and energetic conditions of dispersion and their difference in various bead mills, it is not surprising to learn that the transfer of the results from one machine to another is not automatically possible.

Even if the same bead mill is used, but with different discs, the dwell time distribution of the millbase will be changed and, despite the same number of passes (single pass) or same dispersion time (re‒circulation mode) the dispersion result will also change. Nevertheless, if different bead mills are to be compared with each other, it is generally the case that production machines have less adjustment possibilities.

First, the typical result has to be determined on a known millbase. With this typical result (e.g. fineness), a test series should be made with the DISPERMAT® SL laboratory bead mill with LC‒control. The impeller speed should be adjusted and the dispersion continued until the result matches that which can be achieved in production.

If a DISPERMAT® SL with C‒control is available, the tests should be made using mechanical power input. When comparable results have been achieved, the settings on the DISPERMAT® SL can be used to determine results that are possible in production. When milling with constant power input, not only can complicated dispersion processes be performed in a reproducible manner, but different dispersions can be compared exactly. The dispersion results from production machinery are easily repeated with the DISPERMAT® SL and formulations worked out in the laboratory can be transferred into production.

With the DISPERMAT® SL, problematic parameters like product temperature, cooling water temperature or rheological behaviour of the mill base, may be ignored as long as they do not reach limits critical for the product.