| 摘要 |
PURPOSE:To reduce a bowing phenomenon, and to obtain a film having uniform physical properties by orienting the film in the lateral direction by a tenter, providing a cooling process satisfying formula (I), cooling the film at a glass transition temperature or lower, conducting thermal fixing at a first stage by the tenter and performing thermal fixing at a second stage by a roll. CONSTITUTION:A thermoplastic film extruded by a T die 1 is quenched by a chill roll 2, and molded in a filmy shape. The film is oriented in the vertical direction by roll stretching machines 3 and 3', and passed through a preheating zone 6 while both ends are gripped by the clip 5 of a tenter 4, and introduced into a lateral orientation zone 7 and laterally oriented. The film is admitted into a cooling zone 8, passed through thermal fixing zones 9 and 10, thermally fixed at a first stage, removed from a clip 5 and discharged from the tenter 4, and thermally fixed at a second stage by a roll thermal fixing machine 11, and wound by a winding machine 12. |
