POLYESTER FILM, METALLIZED POLYESTER FILM AND FILM CAPACITOR

摘要

PROBLEM TO BE SOLVED: To obtain a polyester film excellent in wet-heat resistance life under high-temperature high-humidity conditions and capable of giving a capacitor made proof against a puncture at low voltage by treating the surface of a polyester film. SOLUTION: This film is prepared by coating at least either surface of a biaxially oriented polyester film with water-soluble and/or water-dispersible epoxy compounds and heat-treating the wet film to form a coating film thereon. When an unoriented or uniaxially oriented polyester film is used, it is coated with a water-soluble and/or water-dispersible epoxy compounds, and the coated film is oriented and heat-treated. The film has desirably a water absorptivity of 3wt.% or below. It has desirably a surface roughness SRa of 100nm or below and a maximum surface roughness SRmax of 2,000nm or below. It has a heat shrinkage of 1.5% or below after it is treated at 150 deg.C for 30min.