| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat-resistant base film capable of providing a magnetic recording medium that is able to keep good electromagnetic conversion characteristics over a long time and is excellent in durability and also a method for making the film. SOLUTION: The aramide film contains particles having an average primary particle size of 20 nm to 100 nm wherein when the number of projections having a height of from 10 nm to 20 nm is taken as N1, the number of projections having a height exceeding 20 nm but not larger than 50 nm is taken as N2 and the number of projections exceeding 50 nm is taken as N3, at least, on one surface of the film, 3×106 projections/mm2>=N1>=5×105 projections/mm2, (N1/15)>=N2, and 1×104 projections/mm2>=N3. |
