| 摘要 |
PURPOSE:To improve molding stability when a film is biaxially oriented and to make accuracy of the thickness of an obtd. film good by setting a manufacturing condition based on the max. orientation stress of the film in the machine direction and the max. oriented stress of the film in the transverse direction. CONSTITUTION:When the max. orientation stress in the machine direction (MD) and the max. orientation stress in the transverse direction (TD) of a multilayered film biaxially drawn by means of a tubular process and having a nylon-6 layer, an adhesive resin layer and a polyolefin layer are respectively sigmaMD and sigmaTD, sigmaMD and sigmaTD are set respectively by formulas 400 kg/cm<2=sigmaTD<=700kg/cm<2> and 400kg/cm<2=sigmaMD<=700kg/cm<2>, wherein sigmaMD is expressed by sigmaMD = (FXBMD)/A, F=T/r wherein F is an orientation force (kg); BMD is an orientation ratio in the MD direction; A is a cross sectional area (cm<2>) of a raw film; T is a rota tional torque of a nip roll (kg.cm); r is a radius (cm) of the nip roll. In addition, sigmaTD is expressed by sigmaTD =( PXR)/t wherein P is a pressure (kg/cm<2>) in a valve; R is a radius (cm) of the valve; t is a thickness (cm) of the film. |
