Patent ID: 7794849

Claim:
A coextruded, biaxially oriented film structure comprising a base layer comprising a thermoplastic polymer and a first outer layer comprising a thermoplastic polymer that has a melting point of not more than 230° F. (110° C.) characterised in that: a) the thermoplastic polymer of the base layer is an isotactic propylene homopolymer having an isotacticity of from 89 to 99%, a melting point of from 311° F. (155° C.) to 329° F. (165° C.) and a melt flow rate of from 0.5 to 15 g/10 minutes measured according to ASTM 1238, and b) the thermoplastic polymer of the first outer layer is selected from the group consisting of ethylene plastomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers or terpolymers and blends thereof, the film structure being prepared by coextruding melts corresponding to each individual layer of the film structure through a die to form a coextruded film sheet and simultaneously biaxially orienting the coextruded film sheet on a line using linear motors that directly propel opposed pairs of tenter clips synchronously.