| 摘要 |
PURPOSE:To obtain the titled film excellent in tensile strength, surface smooth ness, etc., by forming a solution of a high-intrinsic viscosity acrylonitrile polymer into a film by a dry/wet process and subjecting the obtained coagulated film to primary drawing and to secondary drawing under applied dry heat. CONSTITUTION:A solution of an acrylonitrile polymer of an intrinsic viscosity >=2.5 is obtained, for example, by (co)polymerizing acrylonitrile by a solution polymerization process. This polymer solution is first discharged into air or an inert atmosphere through a slit die and then lead to a coaulant solution of form a coaglated film. The obtained film is converted into a drawn film of a effective overall draw ratio of at least 7 by primary drawing and secondary drawing under applied dry heat at 180-230 deg.C. In this way, a film comprising the high-polymerization degree acrylic polymer having a tensile strength of at least 300kg/mm<2> and excellent surface smoothness can be obtained. |
