| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of elongation, deformation and wrinkles during tenter feed by specifying the blow-off angle from a blow-off port until the amt. of the solvent remaining in the web peeled from a support becomes a specific value, and specifying the difference between the upper and lower limit values of the wind velocity distribution on the surface of a film to blow off the drying gas. SOLUTION: A dope film (web) 1 of a cellulose acetate soln. (dope) peeled at a peel point 4 is introduced into a drying zone 9 while the dope cast on a support 3 from a die 2 is dried and fed by a tenter to be dried by the drying gas blown off from dryers 10 provided above and below the web 1. At this time, the blow-off angle of the drying gas from a blow-off port 14 is set to 30-150 deg. with respect to the plane of a film until the residual amt. of the solvent in the web 1 peeled from the support 3 becomes 4 wt.% and, when the wind velocity distribution on the surface positioned in the blow-off entending direction of the drying gas is set on the basis of the upper limit value of wind velocity, the difference between upper and lower limit values is set within a range of 20% or less of the upper limit value to blow off the drying gas to perform drying. |
