Patent ID: 7223459

Claim:
A coextruded, transparent, biaxially oriented polyester film comprising a base layer (B) and a coextruded, uncoated heatsealable top layer (A) which is peelable from at least CPET, the heatsealable and peelable top layer (A) consisting of a) about 80–98% by weight of polyester and b) about 2–10% by weight of inorganic and/or organic particles having an average diameter d 50 of from about 2.5 to 12.0 μm (based on the mass of the top layer (A)), wherein c) the polyester used to form said layer (A) is composed of about 12–89 mol % of units which derive from at least one aromatic dicarboxylic acid and about 11–88 mol % of units which derive from at least one aliphatic dicarboxylic acid, the sum of the dicarboxylic acid-derived molar percentages being 100, d) the ratio of particle diameter d 50 and layer thickness d A of the top layer (A) is greater than/equal to about 1.0, e) the layer thickness of the top layer (A) d A is from about 2.3 to 10.0 μm, f) said film does not tear during removal from CPET, and g) said top layer (A) exhibits a surface roughness, Ra, ranging from greater than 60 to 400 nm, as determined via DIN 4768.