Patent ID: 6866920

Claim:
A transparent, biaxially oriented polyester film with a base layer B which is composed of at least 80% by weight of a thermoplastic polyester, and with an outer layer A directly adhered to base layer B, and with a polymeric layer arranged on that side of the film opposite to the outer layer A, wherein the outer layer A comprises a copolymer or a mixture of homo- and copolymers which comprises 91 to 98% by weight of ethylene 2,6-naphthalate units and up to 9% by weight of ethylene terephthalate units, and/or units made from cycloaliphatic or aromatic diols and/or dicarboxylic acid; the thickness of the outer layer A is more than 0.7 μm and the outer layer A makes up less than 25% by weight of the entire film; the T g 2 of the polyester film is above the T g 2 of the polyester for the base layer B, but below the T g 2 of the polyester for the outer layer A; the polymeric layer arranged on that side of the film opposite to the outer layer A is composed of a copolymer having acrylic and/or methacrylic crosslinking, said film exhibiting an oxygen transmission of less than 85 cm 3 /(m 2 bar d) and an adhesion between the individual layers of greater than 0.5 N/25 mm.