Co-extruded, heat sealable and peelable polyester film with high peelability, process of producing the same and its use

摘要

Coextruded, transparent polyester film with a heat-sealable and peelable (at least against APET) outer layer (A) with a thickness of 1.3-3.0 microns, comprising (a) 50-95 wt% polyester and (b) 5-40 wt% polyester-incompatible (anti-PET) polymer, in which the polyester comprises 20-95 mol% aromatic dicarboxylic acid units and 5-80 mol% aliphatic diacid units. An independent claim is also included for a method for the production of this film by feeding the polymers for base layer (B), outer layer (A) and optionally another outer layer (C) into separate extruders, passing the melts through a multi-layer die to form flat, coextruded melt film, drawing off and solidifying the multilayer film over a cooling roller and optionally other rollers, stretching first in the machine direction (MD) at 60-130[deg]C (by a ratio of (2:1)-(5.5:1)) and then in the cross direction (TD) at 90-140[deg]C (by a ratio of (2.4:1)-(5.0:1)), and then heat fixing.