Patent ID: 6855395

Claim:
A coextruded, transparent, biaxially oriented, sealable polyester film with at least one base layer (B), with a sealable outer layer (A) on one surface of the base layer (B), and with another outer layer (C) on the other surface of the base layer (B), where the sealable outer layer (A) has a minimum sealing temperature (fin) of not more than 110° C. and a seal seam strength (fin) of at least 1.3 N/15 mm of film width, and wherein the two outer layers (A) and (C) are characterized by the following features: Sealable outer layer (A): a) comprises particles composed of synthetic SiO 2 at a concentration of from about 500 to about 5000 ppm, with a median particle diameter d 50 of from about 2.5 to about 10 μm, the SPAN98 of the diameter being less than or equal to 1.80, b) has roughness R a greater than 60 nm, c) has a side A/side A coefficient of friction smaller than 0.8, and non-sealable outer layer (C): d) comprises particles composed of synthetic SiO 2 at a concentration of from above 1000 to about 5000 ppm with a median particle diameter d 50 of from 1.5 to about 6 μm, the SPAN98 of the diameter being less than or equal to 2.0, e) has roughness R a such that 30≦R a ≦150 nm, f) has a side C/side C coefficient of friction smaller than 0.6.