TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The base layer B comprises at least 65 wt.% of thermoplastic polyester and up to 35 wt.% of additives. The additive is a hydrolysis stabilizer. The thermoplastic polyester of the base layer B: is a polyester with low carboxy end group content; and comprises up to 25 wt.% of ethylene-acrylate copolymer. The outer layer A comprises: at least 75 wt.% of the mixture comprising ethylene-acrylate copolymer and polyester; and up to 25 wt.% of additives. The ethylene-acrylate copolymer is a copolymer comprising ethylene and at least one acrylate, where the acrylate is ethyl acrylate, ethyl methacrylate, methyl acrylate, methyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, 2-octyl acrylate, 2-octyl methacrylate, undecyl acrylate, undecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, dodecyl acrylate, dodecyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl acrylate, or 2-hydroxyethyl methacrylate. The melt index of the ethylene-acrylate copolymers (2.16 kg/190 degrees C), measured to DIN EN ISO 1133, is 0.5-50 g/10 minutes. EXAMPLE - Pellets of polyethylene terephthalate (96 wt.%) and polyester pellets comprised Sylysia 320 (RTM: Porous silicon dioxide) (0.5 wt.%), Ti-pure R-104 (RTM: Rutile Titanium dioxide) kneaded in a twin-screw extruder into polyester pellets (39.5 wt.%) were introduced in a twin-screw extruder with devolatilization for the base layer (B). A mixture made of polyethylene terephthalate (12 wt.%) and LOTRYL 24 MA 07 (RTM: Ethylene-methacrylate copolymer) (88 wt.%) was introduced in a twin-screw extruder with devolatilization for the outer layer A. The content of methacrylate in the ethylene-methacrylate copolymer used was 9.4 mol.%, corresponding to 24 wt.%, based on the copolymer. The melt flow index (2.16 kg/190 degrees C.) was 7 g/10 minute. The raw materials were respectively melted, homogenized, and devolatilized in the twin-screw extruders. The temperature in the extruder outlet and melt line for the base layer here was maintained at 284 degrees C, and the temperature in the extruder outlet and melt line for the outer layer A was maintained at 265 degrees C. The resultant melt film was applied to a cooled casting roll (chill-roll temperature 30 degrees C) and cooled. Simultaneous orientation of the pre-film (stretching temperature 106 degrees C, longitudinal stretching ratio 3.6 and transverse stretching ratio 3.8) and subsequent heat-setting (maximum temperature 242 degrees C for 1 second) to give a two-layer biaxially oriented film of AB structure. After the hottest zone of the heat-setting process, the material was relaxed by 3.5% transversely and 2% longitudinally, at 185 degrees C to give a film with total thickness of 200 mu m.