Micro-compounding is the mixing or processing of polymer formulations in the melt on a very small scale, typically several milliliters. The advantage of the use of a micro-compounder for R&D are significant: it gives faster, yet reliable results with much smaller samples and at much less investment costs, thus speeding up the innovation process in R&D of polymer materials, pharmaceutical, biomedical and nutritional applications.
Micro-compounding is typically performed with a table top, twin screw micro-compounder or -extruder with a working volume of 5 or 15 milliliters. With such small volumes it is almost impossible to have sufficient mixing in a continuous extruder. Therefore, state of the art micro-compounders have a batch mode (recirculation) and a conical shape. The L/D of a continuous twin screw extruder is mimicked in a batch micro-compounder by the recirculation mixing time, which is controlled by a manual valve. With this valve the recirculation can be interrupted to unload the formulation in either a strand, or an injection moulder, a film device or a fiber line. Typical recirculation times are 1-3 min, dependent on the ease of dispersive and distributive mixing of the formulation.