A Computer Controlled Polypropylene Stretched Tape Line To Investigate the Effect of Processing Conditions On Stretched Tape Morphology and Properties

Abstract

A computerized stretched tape line has recently been installed at the Shell Westhollow Research Center. Tape line variables currently under computer control are godet roll speed (feed, draw, and annealing godets), quench bath temperature, orientation oven temperature, and annealing roll temperature. Godet rolls are con trolled and driven by Fincor inverters and A.C. synchronous motors. The line has data logging capabilities as well as a ramping function which provides smooth speed transitions while stringing up the line or changing the draw ratio. Recent work on the new tape line investigated the effect of resin melt flow and molecular weight distribution (MWD) on the tape's mechanical properties and dimensional stability (as measured by a shrinkage test of yarn in skein form at 132°C). The data showed that effect of MWD and melt flow on tape mechanical properties was comparable to that found with our previous work [1]. There was little or no effect of MWD on tape tenacities while Young's modulus and percent elongation at break were mildly affected by MWD. Tape made from higher melt flow resin had lower mechanical properties. Shrinkage decreased as MWD broadened and also with higher on-line annealing temperatures.