| abstract |
The application discloses a transparent, biaxially oriented polyester film having a base layer at least 80% by weight of which is composed of a thermoplastic polyester, and having at least one outer layer, wherein the outer 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 up to 60% by weight of ethylene terephthalate units and/or units from cycloaliphatic or aromatic diols and/or 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 outer layer, where the base layer comprises particles and the Ra value of at least one surface is between 1 and 1000. The film has low gas transmission. It is particularly suitable for packaging uses, specifically for packaging foodstuffs and other consumable items, or as magnetic tape film and as capacitor film. |