| 摘要 |
PURPOSE:To eliminate sags in the center and wavy edges by providing rolls for setting respective film speed after being folded, specifying the roll speed ratio and setting the film temperature as the specific relation. CONSTITUTION:Rolls A-C can be set respectively by means of nip rolls pinching from both sides. The roll speed ratio B/A and the roll speed ratio C/B satisfy 1.0<B/A<1.2, 0.8<C/B<1.0. When the line speed ratio B/A of the rolls is 1.0 or less, orientation is not carried sufficiently to leave residual distortion, while when 1.2 or more, the tearing strength in the film flow direction is lowered and not recommended. When the roll speed ratio C/B is 0.8 or less, the film winds onto the rolls, while when 1.0 or more, film stress cannot be released. When the film temperature is set as T1 before a roll B, T2 just after passing through a heating tank and T3 before a roll C, T1<T2, 5<T3<80 deg.C is established. When the temperature T2 is on the side lower than T1, the residual distortion of film is not released. When the temperature T3 comes up to 80 deg.C or higher, creases are generated in a winding raw fabric of film. |
