Polyester film for electrical insulation

Abstract

An electrical insulating polyester film has an apparent density of 1.37 to 0.85 g/cm.sup.3 and a tensile modulus of 2.0 to 4.5 GPa. A film having low oligomer content, low cost, high heat resistance, high impact resistance, superior machinability and processability, assembling stability, and superior visibility is obtained. Furthermore, leakage of current is reduced when it is used for motor insulation.

Dependencies are inferred from the claim text.