THEORETICAL AND EXPERIMENTAL INVESTIGATIONS INTO SCREWS FOR EXTRUDINGPOLYPROPYLENE

In the processing of polypropylene via a melt, the extruder exerts an important influence on product quality. Trials were carried out on pro duction extruders with the aim of improving melt quality. As an aid to evaluating the screws, a computer model was developed which could sim ulate extruders. This model is described in the first part of this pap er. In the second part, the computer model is tested using experimenta l data taken from a range of different extruders. The comparisons illu strate the excellent correlation and hence validity of the model. On t he basis of these results, recommendations are given for the optimizat ion of single-screw extruders.