| 摘要 |
PURPOSE:To stabilized the forming conditions of the above film during drawing operation and improve the accuracy in the thickness of the film by specifying maximum drawing stresses set in both moving and transverse directions of the film. CONSTITUTION:A maximum drawing stress sigmaMD set in the moving direction MD of a film 1 and a maximum drawing stress deltaTD set in the transverse direction TD of the film 1 are taken as parameters, and the production conditions of the film are set based on this parameter. More particularly, sigmaMD and sigmaTD are set to 700kg/cm<2=sigmaTD<=1500kg/cm<2> and 700kg/cm<2=sigmaMD<=1500kg/cm<2>, respectively, provided that sigmaMD and sigmaTD are represented by the formulas 1, 2, respectively. In these formulas, F represents drawing force kg, BMD a draw ratio in the MD direction, A the sectional area cm<2> of a raw fabric film, T the rotational torque kg.cm of nip rolls, 'r' the radius cm of the nip rolls, P pressure kg/cm<2> in a bubble, R the radius cm of the bubble, and 't' the thickness cm of the film. |
