Dispersion Problems? The How and Why!, 1999 Polymers, Laminations & Coatings Conference Proceedings
Natti S. Rao
Plastics Solutions International
Ray Edwards
Eastman Chemical Company
Bruce Foster
Eastman Chemical Company
Extension of the work performed on extrusion screws with and without mixing sections, in which the extrusion
coating resin systems, LDPE+TiO2 and LDPE+CaCO3, were used, has led to a quantitative assessment of the mixing of the polymer with the filler. The mixing process involves resin viscosity, filler type, screw geometry and process parameters.
A calculation procedure has been developed which predicts the dispersion of inert fillers in polymer melts during
the extrusion process. The calculations are based upon computer simulations of the following parameters: melting profile; melt temperature; shear rate in the screw channel; local; and total power along the screw length.
This procedure also enables one to determine the screw geometry necessary to blend a particular filler with a
particular resin.
Dispersion Problems? The How and Why!, 1999 Polymers, Laminations & Coatings Conference Proceedings
