| 摘要 |
PROBLEM TO BE SOLVED: To provide a film having good abrasion resistance, electromagnetic conversion characteristics and slitting properties during film and magnetic recording medium production, with good productivity and low cost. SOLUTION: A biaxially-oriented laminated polyester film comprises a layer A1 and a layer A2 , each comprising a polyester, laminated on each of the surfaces of a layer B comprising a polyester, wherein the polyester layers A1 and A2 contain crosslinked polymer particles and inorganic particles and simultaneously satisfy the equations (1)-(4) as follows: 0.1<=A1 d/A2 d<=0.20...(1), 2<=A2 Ra-A1 Ra<=5...(2), 0.020<=Δn<=0.030...(3), 1.1<=YTD/YMD<=1.5...(4) (wherein, A1 d and A2 d denote a laminated thickness of the layer A1 and the layer A2 , respectively; A1 Ra and A2 Ra denote an average roughness of the layer A1 and the layer A2 , respectively;Δn denotes the difference of a refractive index in the lateral direction (nTD) and a refractive index in the longitudinal direction (nMD); YMD denotes a Young's modulus of the film in the longitudinal direction; and YTD denotes a Young's modulus of the film in the lateral direction).
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