Extrusion of Polyethylene Through a Square Slot in Rotating Die Systems

Abstract

In a melt extrusion process consisting of a static die (spinneret), the geometry of extrudate is mainly dependent upon die slot geometry, rheological properties of polymer, pressure drop and drawing conditions. However, in a patented Netlon^® process, a static die is replaced by two counter-rotating dies in a melt extrusion process for producing a net structure. In the present study, a series of net structures was produced from a square die slot under a given set of experimental variables (melt flow index, screw speed, take-up speed, die rotational speed and die temperature) based upon the full factorial design. Subsequently, the filament geometry within the net structure was characterized in terms of shape and cross-sectional area. The filament shape was comparatively more complex, and thus it was characterized by means of `Wadell roundness'. Combined effects of two experimental variables were also analyzed on the filament geometry.

Keywords

die slot filament melt extrusion net polyethylene roundness

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