| 摘要 |
PROBLEM TO BE SOLVED: To improve the cutting resistance of a film end face during regeneration by setting up the average surface roughness of one side of a biaxially oriented polyester film within a prescribed range and the longitudinal Young's modulus of the film at a prescribed value or above. SOLUTION: Inactive particles in the form of slurry are dispersed in ethylene glycol of a diol component, and the ethylene glycol is polymerized with a prescribed dicarboxylic acid component to be incorporated in PET(polyethylene terephthalate). Next, the particles, after being dried, are supplied to a melt- extruding machine, extruded in a sheet shape from a slit-shaped die, and cooled/ solidified on a casting roll, and an unoriented film is made, stretched biaxially, and oriented biaxially. The average surface roughness of one side and intrinsic viscosity of the film are made 3-25 nm and 0.65-1.0 dl/g respectively, and the longitudinal Young's modulus of the film is made at least 7 GPa. |
