Edge Effects in Film Casting of Molten Polymers

Abstract

In most analyses of the film casting process, edge effects such as neck-in and edge beading are usually neglected. In this work, we investigated the significance of these effects and their dependence on the rheological properties of the melts, the draw ratio, and the extrusion rate. Two linear low-density polyethylene melts and a low-density polyethylene melt were considered. The rheological behaviors of these melts were characterized under shear and elongational flows. Streamlines from the die exit to the chill roll, velocity profiles, film tension, neck-in profiles, thickness profile of the solidified film, and edge bead thickness profile were examined.