Multiple layer, biaxially oriented polyester film

摘要

White, co-extruded, biaxially oriented polyester film comprises: a base layer and at least one top layer, where the base layer predominantly consists of thermoplastic polyesters, which comprise ethylene isophthalate derived units (8.5-20 wt.%) and a white pigment in a concentration of 2-15 wt.% based on the base layer, and the top layer predominantly consists of thermoplastic polyesters, which comprise a white pigment in a concentration of 2-15 wt.%, and an additional anti-blocking agent (0.05-2 wt.%) with an average diameter of 2-8 mu m based on the top layer. An independent claim is also included for producing the film, comprising compressing the raw materials of the individual layers of the film in an extruder; liquefying to melt; then simultaneously pressing the melts by a slot die; and thus removing the formed, extruded, multilayer film on at least one cold withdrawing roller, where the melt is cooled and solidified to a precursor film; and then biaxially stretching, thermo-fixing, and rolling up the precursor film.