Use of experimental design to investigate processing conditions and K value effects in poly(vinyl chloride) window profile extrusion

Statistical experimental design has been used on a laboratory scale, twin screw extruder to investigate how processing conditions and polymer K value affect both the extrusion process and important extrudate properties: viz. Charpy impact strength, colour, gloss, and degree of gelation. It is demonstrated how this approach can be used to define the optimum processing window. Although in production situations it may be impractical or too expensive to vary large numbers of variables over a wide processing range, it is possible to use the experimental design approach without initiating unwieldy experimental programmes by using Evolutionary Operation. This is illustrated with reference to extrusion line trials.