| 摘要 |
PROBLEM TO BE SOLVED: To obtain a support having excellent smoothness by setting area density, distance and number of groups of an inclusion existing on a surface in contact with a film to specific values. SOLUTION: The density of inclusions of 40μm or larger on a surface of a support is necessary to be 4 pieces/cm<2> or less. If the frequency is more than it, the inclusion is transferred to a film at the time of film forming, and they becomes coarse protrusions, so that satisfactory surface cannot be obtained. And, an inclusion group of inclusions of 20μm or more exist nearly within 30μm is necessary to be two groups/cm<2> or less. If the number of groups is more than two, the groups are transferred to the film at the time of film forming, and they becomes coarse protrusions, so that satisfactory surface cannot be obtained. Such a support has excellent surface properties, and the solution film forming film manufactured by using it has extremely excellent surface properties. Particularly, when it is manufactured by using a support of aromatic polyamide film, its surface properties are extremely satisfactory to obtain smooth surface required for a film for a magnetic recording medium. |
