| 摘要 |
PURPOSE: To provide a satisfactory cutting property, prevent the decay of a magnetic material and improve productivity, by slitting a recording medium original film at a low temperature within a specified range. CONSTITUTION: A non-shaped sheet formed by melting at 290 deg.C and pushing out a chip of polyethylene terephthalate having an intrinsic viscosity of 0.62 is drawn at 220 deg.C in longitudinal and lateral biaxial directions and then thermally fixed, thus providing a base film. A magnetic material with a thickness of 3μm is applied onto the base film and dried at 120 deg.C, thereby forming a recording medium original film F with a thickness of 18-20μm. After the original film F is passed through guide rolls 1, 3 and then through a cooling roll 2 at a contact angle of 180 deg., the original film F is slit by a slitting cutter of a shear cutting system composed of an upper blade 4 and a lower blade 5 at a rate of 300m/minute, thus providing a recording medium tape. The surface of the cooling roll 2 is held at a low temperature and the temperature of the original. film F at the time of entry of the slitting cutter is set at 5-20 deg.C. |
