| 摘要 |
PROBLEM TO BE SOLVED: To provide a laminated biaxially oriented polyester film being a self-circulating recoverable laminated film excellent in electromagnetic conversion characteristics as a base film for a high density magnetic recording medium and also excellent in take-up properties and handling properties as a base film. SOLUTION: A polyester A layer and a polyester B layer satisfy the relation of WRa (B)>WRa(A), (tB/t)×100=50-90(%) and 10<tB/dB<=60, wherein WRa (A) is the surface roughness (nm) of the polyester A layer, WRa (B) is the surface roughness (nm) of the polyester B layer, tA is the thickness (μm) of the polyester A layer, tB is the thickness (μm) of the polyester B layer, t is the total thickness (μm) of the film and dB is an average particle size (μm) of the lubricant particles contained in the polyester B layer. |
