| 摘要 |
PURPOSE:To obtain a polyester film having a low noise level and a good signal to noise ratio in data reading by forming the film layer of the polyester formed by dispersing the ester product of polyol having >=3 hydroxyl groups and aliphat. monocarboxylic acid having >=8C into a polymer at a specific wt%. CONSTITUTION:A film layer forming a surface A on which a thin magnetic film consisting of a laminated film is carried is constituted of polyester in which >=80wt% of the polymer weight consists of polyethylene terephthalate. The other surface B is formed of the polyester film which has surface roughness [CLA (unit: mum)] and number of projections of >=0.54mum height [H2 (unit: pieces/mm.<2>)] satisfying respectively the formulas 0.007mum<CLA<=0.03mum, 2<H2<=150 and consists of >=80wt% polyethylene terephthalate formed by dispersing the ester product of polyol having >=3 hydroxyl groups and aliphat. monocarboxylic acid having >=8C into a polymer at 0.01-5wt%. |
