| 摘要 |
PURPOSE:To obtain many films without thickness irregularity by specifying crystallinity of at least one polyester film, superposing two or more polyester films, then longitudinally stretching and/or heat setting it, and then peeling respective films. CONSTITUTION:Two or more polyester films in which crystallinity of at least one polyester film before superposing is 1% or more are superposed, then at least longitudinally stretched and/or heat set, peeled to the respective films, thereby manufacturing two or more polyester films simultaneously. To this end, when polyester is melted and extruded via a T die and cooled to be solidified in a sheet state on a cooling roll, a surface material quality and temperature of the cooling roll are controlled to crystallize it in a cooling step, thereby obtaining an object crystallinity. |
