| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of surface defects in a film forming process and working processes such as a magnetic layer applying by giving specific surface roughness and friction coefficient between films with each other to the film for a high density floppy disk having thin film thickness and smooth surface. SOLUTION: The film is made of a polyester resin which has 0.05 to 1.0wt.% particles of >=0.05 to <1.0μm average grain size and substantially contains no particles of >=1.5μm average grain size and, further, the film has 25 to 70μm thickness, 4 to 12nm center line average surface roughness (Ra) on both film surfaces, 0.55 to 0.8 static friction coefficient and 0.35 to 0.53 dynamic friction coefficient between the films.
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