Large Part Blow Molding (LPBM) of HDPE Resins: Parison Extrusion Behavior and its Relationship with the Resins' Rheological Parameters

摘要

In order to find the right combination of material properties and processing conditions (blow moldability) for the production of a molded part that has a set of predetermined final properties, it is necessary to characterise the material behaviour under the actual processing conditions. Relating this to the rheological properties (under controlled experimental conditions) of the material, it is possible to design the molecular characteristics of the material in such a way as to attain the desired processing characteristics. This paper presents the results of a study examining the relationships between some basic rheological properties and the key processing material behavior parameters (swell and sag) governing the blow molding process. The technique has been applied to the intermittent extrusion of three HDPE LPBM resins manufactured using three different catalyst and process technologies.