Peelable polyester film with self-venting, process for its production and its use

摘要

Coextruded, biaxially oriented polyester films which have a base layer (B) and have a heatsealable outer layer (A) that can be peeled from APET/CPET and from CPET, where the outer layer (A) includes 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 d₅₀ of from 3 to 12 mum, and where c) the polyester 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, and d) the ratio calculated from the particle size d₅₀ of the particles and the layer thickness d_A of the outer layer (A) is greater than or equal to 1.5, and the shrinkage of the films, at least in one direction, is more than 5%. The films of the invention are especially suitable, owing to their property of self-venting, as a lid film for APET/CPET or CPET trays.