Impact of lubricants on processing behaviour of U-PVC

ISSN： 1743-2898

Source： Plastics, Rubber and Composites, Vol.34, Iss.3, 2005-03, pp. : 143-147

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Abstract

The influence of different chemical classes of waxes, used commercially as internal and external lubricants, on the processing behaviour of PVC in profile extrusion is described, drawing on the results of systematic laboratory testing. The present study concentrates on long chain ester waxes, oxidised polyethylene waxes and polyethylene/polypropylene waxes. The last of these three product groups covers the state of the art polyethylene waxes and the new class of metallocene waxes. The influence of the waxes on processing behaviour has been analysed on the basis of extruder pressure and screw torque measurements and extruder energy consumption. The influence of lubricants on the surface quality of profiles is also considered. It is concluded that the effect of PO-waxes and oxidised PE-waxes on the processing behaviour can be correlated with product parameters such as crystallinity, viscosity and acid value. Long chain ester waxes, i.e. montanic waxes, provide additional effects and allow for the adjustment of individual processing parameters.