| abstract |
(57) [Abstract] [Problem] Useful as a base film for a magnetic recording medium, which is excellent in winding property, defect-free property, slipperiness, and handling property, and is particularly excellent in electromagnetic conversion characteristics, dropout, running property, and durability. A laminated film is provided. A thermoplastic resin containing inert particles A having an average particle diameter of 40 to 400 nm and a volume shape factor of 0.1 to π / 6 in an amount such that the surface projection frequency is from 50,000 to 50,000 particles / mm 2 . A biaxially oriented laminated film in which a thermoplastic resin layer B containing inert particles B and having a rougher surface than the thermoplastic resin layer A is laminated on one surface of the resin layer A, the thermoplastic resin comprising: The surface of layer A is 0 ± 10 in the longitudinal direction of the film. In the direction of degrees, height 2-85 nm, average width 20-500 μ A laminated film having m wavinesses at a frequency of 4 to 2500 pieces / mm 2 . |