Patent ID: 7541088

Claim:
A biaxially oriented at least two-layer coextruded film comprised of polyethylene terephthalate (PET) or polyethylene 2,6-naphthalate (PEN), said PET or PEN optionally including additional comonomer-derived units other than ethylene glycol and/or terephthalic acid or naphthalene-2,6-dicarboxylic acid, said film comprising a base layer and at least one exterior outer layer, wherein the base layer comprises a white pigment and a laser absorber which has been coated with a carbonizing polymer, the thickness of at least one of said exterior outer layer(s), which comprises no laser absorber, is at least 3 microns, and said film has a modulus of elasticity of greater than 3.5 GPa in the longitudinal and transverse directions as measured via DIN EN ISO 572-1 and -3.