Patent ID: 7211306

Claim:
A coextruded, biaxially oriented polyester film which has a base layer (B) and has a coextruded, uncoated heatsealable outer layer (A) that can be peeled from APET/CPET and from CPET, where the outer layer (A) comprises a) from 80 to 98% by weight of polyester and b) from 2 to 10% by weight of inorganic and/or organic particles with a median diameter d 50 of from 3 to 12 μm, and where c) the polyester used to form said layer A is composed of from 12 to 89 mol % of units derived from at least one aromatic dicarboxylic acid and of from 11 to 88 mol % of units derived from at least one aliphatic dicarboxylic acid, where the total of the dicarboxylic-acid-derived molar percentages is 100, d) the ratio calculated from the particle size d 50 of the particles and the layer thickness d A of the outer layer (A) is greater than or equal to 1.5, e) the shrinkage of the film, at least in one direction, is more than 5% measured at 100° C. over a period of 15 min and f) said film does not tear during removal from CPET, based on a sealing temperature of 160° C. and g) said top layer (A) exhibits a surface roughness, Ra, ranging from greater than 120 to 400 nm, as determined via DIN 4768.