| 摘要 |
PURPOSE: To improve thermal dimensional stability, output properties, and resistance to edge damage by heating a polyethylene terephthalate film. CONSTITUTION: An unstretched film of polyethylene terephthalate containing 0.01-3.0wt.% particles having a diameter of 0.01-1.0μm is stretched in the machine direction 3.0-6.0 times at 75-175 deg.C and a stretching rate of 5,000-50,000%/min and then stretched in the transverse direction 3.5-7.0 times at 80-170 deg.C and a stretching rate of 1,000-20,000%/min. The stretched film is heated at 170-220 deg.C to obtain a biaxially oriented polyethylene terephthalate film having a thickness of 0.01-3μm. This film is irradiated for 0.2-300sec with infrared rays having a wavenumber of 600-1,600cm<-1> to obtain the objective film having a crystallinity of 55% or higher and a modulus in the machine and/or transverse direction of 700kg/mm<2> or higher. |
