Patent ID: 7186452

Claim:
Coextruded, transparent, biaxially oriented polyester film comprising a base layer (B) and heatsealable top layer (A) which is peelable from at least the APET side of an APET/CPET tray, the heatsealable and peelable top layer (A) consisting of a) about 50–95% by weight of polyester and b) about 5–40% by weight of a polyester-incompatible polymer or anti-PET polymer, based on the mass of the top layer (A) and c) particles, wherein d) the polyester used to form said top layer (A) is composed of about 20–95 mol % of units derived from at least one aromatic dicarboxylic acid and about 5–80 mol % of units derived from at least one aliphatic dicarboxylic acid, e) the top layer (A) exhibits a roughness, Ra, ranging from greater than 60 nm to 400 nm, as determined via DIN 4768, f) the layer thickness d A is from about 1.3 to 3.0 μm, and g) said heatsealable top layer (A) exhibits a seal seam strength with respect to the APET side of APET/CPET trays of at least about 3 N/15 mm.