POLYESTER FILM FOR MAGNETIC RECORDING DISK

摘要

PROBLEM TO BE SOLVED: To provide a polyester film for a magnetic recording disk which has little surface defects even if the film has low rigidity and a smooth surface and further, in which the amt. of oligomers in the film is controlled by imparting a specific friction coefft. to the film. SOLUTION: This polyester film for a magnetic recording disk consists of a polyester resin containing 0.2 to 0.4 wt.% particles having >=0.04μm and <0.3μm average particle size and without substantially containing particles of >=0.5μm average particle size. The film has 25 to 70μm thickness, 4 to 7 nm center line average surface roughness of the film surface (Ra) and <=45 mg/m<2> oligomer content.