| abstract |
[57] [Summary] [Problem] To suppress the occurrence of tearing and foaming at a pin when a solution film is dried by a pin tenter. A cellulose ester solution is cast onto a support by a casting die, and a cooled and gelled web is peeled off from the support. This web is stretched by a pin tenter to obtain a cellulose ester film. The lip clearance of the casting die is adjusted at each part in the width direction. Thereby, the thickness after drying of the film ear | edge part range A2 in which a pin is inserted is 5-70 micrometers thick with respect to the average thickness ts1 of the product part A1 after drying excluding the ear | edge part, and 1st thickness difference (DELTA) t1 is made. Provide. Since the thickness difference Δt1 is set to 5 μm or more, the occurrence of tearing by the pins can be suppressed. Since the thickness difference Δt1 is set to 70 μm or less, an increase in volatile content in the ear portion is suppressed, and foaming due to the volatile content is suppressed. |