| 摘要 |
A casting dope (27) is cast onto a running casting belt (46) to form a casting film (69). Drying devices are disposed in both surface side of the casting belt (46), so as to dry the casting film (69). The casting film (69) is conveyed through drying zones in which drying temperatures are respectively determined according to the content of remaining solvent in the casting film (69) on the basis of the graph of film production limit line that is different between the main compound of the solvent. Then the drive conditions of each drying device were set, such that the drying of the casting film (69) might be made at the drying temperature. Thus the drying temperatures are previously determined adequately to the content of remaining solvent. Therefore, the drying of the casting film can be made without a large luck of supply with the thermal energy, and the like. |
