PROCESSES FOR INJECTION MOLDING AND EXTRUSION WITH ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE SCREW, AS WELL AS SUBSTANTIALLY DUST-FREE PELLETS

摘要

Ultra-high molecular weight polyethylene (MW1 x 106) powder is compacted into pellets by use of, for instance, a pellet machine. Pellets thus obtained are fed to a screw injection molding machine. The injection molding is carried out under a mold temperature of 50 - 105 DEG C and a barrel temperature of 232-343 DEG C (450 - 650 DEG F). The properties of the molded products are essentially equivalent to those of compression molded products. The pellets also facilitate screw extrusion where the barrel temperature and the die temperature are maintained within the range of 260-371 DEG C (500 - 700 DEG F).