Patent ID: 7238428

Claim:
A biaxially oriented polyester film which has a base layer (B) and comprises at least one overlayer (A), wherein the base layer (B) comprises (i) polyester consisting essentially of polyethylene terephthalate, polyethylene 2,6-naplithalate, poly-1,4-cyolohexane-dimethylene terephthalate, polyethylene 2,6-naphthalate bibenzoate and mixtures thereof; (ii) poly(m-xyleneadipamide) having a melt viscosity smaller than 2000 poises and said overlayer (A) comprises said polyester and, optionally, up to 20% by weight of said poly(m-xyleneadipamide), based on the weight of the overlayer (A), and further exhibits a gloss of greater than 100, said polyester film exhibiting an oxygen transmission (OTR) smaller than 50 cm 3 m −2 d −1 bar −1 and an opacity of less than 20%, said overlayer (A) containing from 0.0001 to 0.5 wt % antiblocking agents, based on the weight of overlayer (A).