Transparent polyester film with high oxygen barrier, its use, and process for its production

摘要

The application discloses a transparent, biaxially oriented polyester film having a base layer of at least 80% by weight which is composed of at least a thermoplastic polyester, and having at least one cover layer, wherein the cover layer is composed of a polymer or a mixture of polymers which comprises at least 40% by weight of ethylene 2,6-naphthalate units and optionally up to 60% by weight of ethylene terephthalate units and/or optionally units from aliphatic, cycloaliphatic or aromatic diols, and/or optionally aliphatic, cycloaliphatic and 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 low atmospheric oxygen transmission. It is particularly suitable for packaging applications, specifically for packaging foodstuffs and other consumable items.