| 摘要 |
PURPOSE:To prevent defect (imcomplete stripping) in which dope is partly left on a band when the dope cast on the band is stripped after drying and also prevent corrugated sheet-like stripe defect (lateral stripe pattern) which is generated at right angles with the direction in which the dope is cast. CONSTITUTION:A cellulose triacetate film is produced by a method wherein dope is cast on a band 1 to be gelatinized and then stripped from the band, thereupon the width of the stripped film is regulated by a tenter 2. In this method, the following tenter draw ratio is set to 100.5 to 110.0%. That is, the tenter draw ratio(%)=AX100/B, wherein A represents tenter speed (m/min) and B represents band speed (m/min). The dope to be used has concentration of 5 to 25wt.% of the sum of cellulose triacetate and other ingredients which are converted into solid after drying, and the ratio of a solvent other than methylene chloride in solvent composition is 8 to 20wt.%. |
