| 摘要 |
PURPOSE:To certainly prevent the generation of folded wrinkles on a film caused by the air bank generated on a roll, in stretching the film between rolls different in a peripheral speed, by applying an electrostatic field to the side of the low speed roll. CONSTITUTION:A polyethylene terephthalate film 1 with a thickness of 20mum biaxially oriented under a stretching condition of 3.5 times in both longitudinal and lateral directions is sent between a low speed roll 2 having a hard chromium plating surface and an electrode 6. The electrode 6 to be used comprises an elastomer roll with hardness of 70 deg. and volume inherent resistivity of 10<5>OMEGA.cm and the contact pressure with the low speed roll is set to 0.5kg/cm<2> and voltage to be applied is set to 1.0kV. An opposed roll comprises an elastomer roll with hardness of 80 deg.. Subsequently, the film 1 is stretched while closely contacted with a high speed roll 3. Even if a stretching magnification reaches 1.4-1.8, folded wrinkles and scratch are not generated. |
