Polymeric films

摘要

Biaxially oriented polyolefin films having a thickness of not more than 50 mu m having a layer of a polypropylene-based resin with microvoids therein, the microvoids having been formed by stretching a web containing the beta-form of polypropylene at an area stretch ratio of at least 15:1. These films have shown particularly uniform opacity when compared with films of a similar thickness which have been voided using chalk as the voiding agent.