| 摘要 |
PURPOSE:To provide a film excellent in running properties and electromagnetic conversion characteristics. CONSTITUTION:A film consists of at least three layers and the A- and B-layers constituting the outermost layers of the film are composed of a substantially identical polyester compsn. and the thickness tA(mum) of the A-layer, the thickness tB(mum) of the B-layer, the surface roughness RaA(mum) of the A-layer and the surface roughness RaB(mum) of the B-layer simultaneously satisfy the formulae of 1.5<=tA/tB<=50... (1), 0.3<=tA<=10... (2), 1.1<=RaA/RaB<=10... (3), 0.010<=RaA<=0.050... (4) and 0.005<=RaB<=0.020... (5). |
