Patent ID: 8475700

Claim:
A process for preparing an oriented polymer composition having a softening temperature and a de-oriented surface layer, both the oriented polymer composition and de-oriented surface layer having a thickness, the process comprising: (a) providing a cavitated oriented polymer composition comprising a continuous oriented polymer phase and having at least one surface comprising oriented polymers and having cross sectional dimensions all exceeding three millimeters; and (b) heating at least one surface of the oriented polymer composition above its softening temperature thereby de-orienting the polymers proximate to the surface to create a de-oriented surface layer that has a thickness of 80 microns or more and at least 50 microns less than half the thickness of the oriented polymer composition, the de-oriented surface layer characterized by having a lower degree of polymer orientation than a 100 micron thick portion of the oriented polymer composition adjacent to the de-oriented layer and more proximate to the center of the oriented polymer composition.