Patent ID: 7182997

Claim:
An opaque, white film with a thickness of from 10 to 500 μm, wherein the film comprises thermoplastic, a pigment, and at least one optical brightener, wherein said thermoplastic consists entirely of polyester and said pigment consists entirely of barium sulfate, wherein the barium sulfate or the optical brightener, or the barium sulfate and the optical brightener have been incorporated directly into the thermoplastic or are fed as a masterbatch during film production, and wherein at least one surface of the film bears a functional coating with a thickness of from 5 to 10 nm, wherein the luminous transmittance of the film is reduced when the longitudinal stretch ratio is increased for a film of the same thickness, said film exhibiting a modulus of elasticity in the transverse direction of greater than or equal to 4200 N/mm 2 .