Orientation development in retensilized,biaxially oriented polypropylene films

A basic study of orientation development in retensilized, biaxially oriented polypropylene films was performed. Wide-angle X-ray scattering (WAXS) and birefringence measurement techniques were used to examine films prepared under specific processing conditions. Biaxial orientation factors were determined for these films and were correlated with end-use properties of the materials. In particular, the dispensability of oriented polypropylene films was found to correlate with crystalline-phase and amorphous-phase orientation factors. Dispensability is a relatively important property of pressure-sensitive tapes; it is defined as the force necessary to cut a film backing over a serrated blade of the type used in commercially available adhesive-tape dispensers.