| 摘要 |
PURPOSE:To obtain a film having uniform physical properties in the lateral direction by orienting a film after lateral orientation in the lateral direction by a cooling process satisfying formula (I) showing a lateral orientation temperature or lower and thermally fixing the film when the thermoplastic resin film oriented in at least the lateral direction is manufactured. CONSTITUTION:When a thermoplastic resin film is laterally oriented and thermally fixed and treated, a film after the completion of a lateral orientation process is cooled at an orientation temperature or lower while being oriented in the lateral direction, thus preventing a bowing phenomenon generated by the lateral orientation process. The effect of the decrease of the bowing phenomenon is improved with the increase of the value of the ratio L/W of the length L of a cooling process to the width W of the film, and it is favorable that the length L of the cooling process is selected at L/W>=2.0 of the ratio of the length L of the cooling process to the width W of the film. L/W>=3.0 is further preferable. It is favorable that the film is passed through speed-controllable nip roll groups in the cooling process after the completion of the cooling process and a thermal fixing process, and the effect is enhanced remarkably. |
