New Silicone Processing AIDS for the Extrusion of Linear Low Density Polyethylene

Various silicone process aid candidates were evaluated and compared to alternative process aids for their effect on surface properties of extruded linear low density polyethylene (LLDPE). Their performance was influenced by the silicone polymer structure and the concentration of the silicone polymer in the polyethylene resin. An increase in the polarity of functional groups on the silicone polymer resulted in an increase in the effect on surface properties of extruded LLDPE. Silicone concentrations in the range 220 to 3520 ppm in the polyethylene resin gave significant reduction in surface roughness caused by melt fracture during extrusion. Concentrations of 10000 ppm or less gave coefficient of friction values of 0.3 or below. Beneficial effects on extruder parameters, such as the reduction of extrusion pressure, current, and output were also observed.