Special Requirements on Compounding Technology for Bimodal Polyolefines and Their Industrial Application

摘要

This paper describes quality criteria and the optimisation of compounding processes for some bimodal polyolefin grades. Quality criteria and testing methods are different for film grades and coloured grades for pipe extrusion or other applications. Even for comparable polymer grades their producers use different quality criteria which makes the direct comparison of those products impossible in terms of compounding demands. Therefore, the quality checks have to be adapted for optimising a compounding process by special screw designs or operating conditions. Some examples for such an optimisation and the resulting industrial compounding lines are shown. In general this new class of polymers requires an enlarged and specially designed melting zone (i.e. multiple zones) and a longer residence time within the compounder. This leads to either lower throughput for a given machine size or requires a bigger machine for a given throughput.