| 摘要 |
PROBLEM TO BE SOLVED: To obtain a film useful for a magnetic recording medium excellent in electromagnetic conversion characteristics, traveling characteristics, or the like, by making the film have specific numbers of fine and coarse protrusions with specific diameters on the surface. SOLUTION: This film has 2,000 to 100,000,000/mm2 of fine protrusions with a diameter of <=1μm and <=200/mm2 of coarse protrusions with a diameter of >=4.5μm on at least one surface of the film. Among the fine protrusions with a diameter of <=1μm, it is preferable that the number of the fine protrusions with a height of >=5 nm and <20 nm is 100,000-20,000,000/mm2, and the number of the fine protrusions with a height of >=20 nm is 2,000-100,000/mm2. Furthermore, it is preferable that the number of the coarse protrusions with a diameter of >=4.5μm is <=50/mm2. The arom. polyamide pref. has a para-oriented arom. ring at a rate of >=70% of the entire arom. rings. For forming the fine protrusions, there is a method, e.g. in which inorg. and/or org. particles are added to the arom. polyamide. A magnetic recording medium is obtd. by providing a magnetic layer to at least one surface of this film.
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