Abstract: The present invention provides an aromatic polyamide film wherein a heat-shrinkage in the TD direction at 220.degree. C. is of 0.2 to 8% under a load of 80 kg/cm.sup.2, and wherein an average ten-point roughness Rz of the surface that is opposite to a surface for providing a magnetic layer is 10 to 200 nm; and a magnetic recording medium, wherein a magnetic layer is provided on a surface of the film. Since the heat-shrinkage at a high temperature and the properties of the surface of the film are within the confines of the present invention, there is obtained a magnetic recording medium having a high degree of flatness with small curls, and a high recording density by using the film.

Abstract: The present invention relates to a film made of an aromatic polyamide having excellent running property, durability and output characteristics when combined with a magnetic medium, and having excellent heat resistance, the number of large protrusions per 100 cm.sup.2 H2 on one surface of the film and the number of large protrusions per 100 cm.sup.2 H3 on the opposite surface of the film satisfy the relationships of:H2.ltoreq.502.ltoreq.H3.ltoreq.100, andthe tensile Young's modulus E20 at 20.degree. C. in at least one direction and the tensile Young's modulus E100 at 100.degree. C. in the same direction satisfy the relationships of:E20.gtoreq.800 kg/mm.sup.20.5.ltoreq.E100/E20.

Abstract: The present invention relates to a magnetic recording medium including a base film made of an aromatic polyamide or an aromatic polyimide, and a magnetic recording layer formed on one surface of the base film, the number of large protrusions H2 on the surface of the base film on which the magnetic layer is to be formed and the number of large protrusions H3 on the surface of the side of the base film opposite to the surface on which the magnetic layer is to be formed satisfying the relationships of:H2.ltoreq.502.ltoreq.H3.ltoreq.100,the tensile Young's modulus E20 at 20.degree. C. in at least one direction and the tensile Young's modulus E100 at 100.degree. C. in the same direction satisfying the relationships of:E20.gtoreq.800 kg/mm.sup.20.5.ltoreq.E100/E20.The present invention provides a magnetic recording medium having excellent durability, running property and output characteristics even under severe conditions at high temperature.

Abstract: The present invention provides a magnetic recording medium including a base film having an aromatic polyamide and a magnetic layer formed on at least one surface of the base film, such that the base film has a tensile Young's modulus in at least one direction of not less than 700 kg/mm.sup.2, a content of materials extractable with methylene chloride of not more than 0.5%, and a dimensional change in the longitudinal direction after applying a load of 1 kg per 1 mm.sup.2 at 100.degree. C. for 10 minutes of not more than 2%. The magnetic recording medium is excellent in running property and durability even under severe conditions.