| abstract |
A biaxially oriented polyester film is disclosed which has a base layer of at least 80% by weight of a thermoplastic polyester, and which has a cover layer and, located on the cover layer, a layer functioning as an O2 barrier, wherein said cover layer is composed of a polymer or of a mixture of polymers which comprises at least 40% by weight of ethylene 2,6-naphthalate units; 0% up to 40% by weight of ethylene terephthalate units; and, if desired, up to 60% by weight of units from other aliphatic, cycloaliphatic or aromatic diols and/or aliphatic, cycloaliphatic or aromatic dicarboxylic acids; with the proviso that the Tg2 value of the polyester film is above the Tg2 value of the base layer but below the Tg2 value of the cover layer. The film has particularly low atmospheric oxygen transmission and has high gloss. It is particularly suitable for packaging light- and air-sensitive foodstuffs and other light- and air-sensitive consumable items, and also for producing insulating materials. |