| 摘要 |
Equally biaxially oriented film is produced by extruding liquified polymer in tubular form, orienting the tubular film in the radial direction only and then either (1) equally orienting the radially oriented film in the longitudinal direction and drying the resultant equally biaxially oriented film while preventing any shrinkage thereof or (2) orienting the radially oriented film in the longitudinal direction to a degree less than said radial orientation but equal to the radial orientation remaining after the biaxially oriented film undergoes radial shrinkage upon drying thereof in the absence of radial shrinkage control and drying the resultant biaxially oriented film in the absence of radial shrinkage control. |
