Impact of roll compaction design, process parameters, and material deformation behaviour on ribbon relative density

Abstract

Ribbons from microcrystalline cellulose (MCC), mannitol, and their 50:50% mixture were produced using the roll compactors AlexanderWerk BT120, Hosokawa Alpine Pharmapaktor C250, L.B. Bohle BRC 25, and Gerteis Mini-Pactor in the frame of multilevel full factorial experimental plans. The specific compaction force (SCF)/hydraulic pressure (HP), gap width (GW), roll speed, and fraction of MCC were analyzed as quantitative factors, whereas the roll surface and sealing system were examined as qualitative factors. Ribbon relative density was investigated as response of the models. The SCF/HP is found to be the most significant factor in each model. A significant inverse effect of the GW is obtained in the models of AlexanderWerk BT120, Pharmapaktor C250, and BRC 25 roll compactors, using smooth rolls. The principle of the establishment of a conversion factor (c_f) is introduced based on the obtained data sets of AlexanderWerk BT120 and Mini-Pactor. This can facilitate the transfer of a roll compaction process between different types of roll compactors.

Keywords: Roll compaction; conversion factor; deformation behavior; process parameters; relative density; roll surface; sealing system.