| abstract |
(57) [Problem] To reduce leakage current, reduce power loss, suppress propagation delay of electronic signals and improve propagation speed, improve heat resistance, improve dielectric breakdown resistance, reduce oligomers, and after assembly Provided is a polyester film for electrical insulation, which is suitable as an insulating material for electronic / electrical equipment, with an improved set stability and an improved ease of assembling the set by coloring. A biaxially stretched polyester film containing polyethylene terephthalate as a main component, The dielectric constant of the polyester film at 1 kHz is 1.5 A polyester film for electrical insulation, wherein the polyester film has an apparent density change rate ΔW of 10% or less when immersed in ethyl alcohol. |