Mineral reinforcement of metallocene-catalyzed lldpe film and bags

摘要

This paper details the effects of adding 7.5percent & 15wt.percent calcium carbonate to three different film resins; two metallocene-catalyzed linear polyethylenes and a conventional Ziegler-Natta catalyzed PE film resin. An LLDPE-based pelleted 75percent calcium carbonate concentrate was used to prepare dry blends with the base resin. These dry blends were extruded into 33mu (1.3 mil) films on a 63mm (2.5"), 24/1 L/D extruder filtted with a 225 mm (9") die and 1.4mm (0.055") die gap. Increasing mineral loading from 7.5percent to 15percent CaCO_3 did not have a significant effect on output rate or other extrusion conditions. Higher levels of mineral concentrate did increase dart impact strength, tear strength, and tensily yield for different film resin blends.