Patent ID: 8168302
Filing Date: 2012-05-01
Classification: A61B,A61N,B32B,C08G,G02B,Y10S,Y10T

Abstract:
1. An oriented polymeric film, comprising: at least one film layer, the film layer comprising a copolyester having an intrinsic viscosity of about 0.4 dL/g to 0.7 dL/g wherein the copolyester comprises glycol subunits and carboxylate subunits, the glycol subunits derived from 70 to 99 mol % C2-C4 diols and about 1 to 30 mol % comonomer glycol subunits derived from 1,6-hexanediol, and the carboxylate subunits being 5 to 99 mol % naphthalate subunits, 1 to 95 mol % terephthalate or isophthalate subunits or mixtures thereof, and 0 to 30 mol % of comonomer carboxylate subunits derived from phthalic acid, t-butyl-isophthalic acid, lower alkyl esters of these acids, or a combination thereof; wherein at least 0.01 to 2.5 mol % of the combined carboxylate and glycol subunits of the copolyester are derived from compounds having three or more carboxylate, ester, or hydroxy functional groups and the film layer has an in-plane birefringence of about 0.04 or less at 632.8 nm.