Patent ID: 7141293

Claim:
A coextruded, transparent, biaxially oriented polyester film comprising a base layer (B) and a, heatsealable top layer (A) which is peelable from at least APET, the heatsealable and peelable top layer (A) consisting of a) about 60–97% by weight of polyester and b) about 3–30% 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 25–95 mol % of units which derive from at least one aromatic dicarboxylic acid and about 5–75 mol % of units which derive from at least one aliphatic dicarboxylic acid, the sum of the dicarboxylic acid-derived molar percentages being 100, e) the top layer (A) exhihits a roughness, Ra, ranging from greater than 60 nm to 400 nm, as determined via DIN 4768, f) the layer thickness of the top layer (A) d A being from about 0.7 to 2.5 μm, and g) said heatsealable top layer (A) exhibits a seal scam strength with respect to the APET side of APET/CPET trays of at least about 1.7 N/15 mm.