| 摘要 |
PROBLEM TO BE SOLVED: To ensure that a large number of foreign substances are not included in a manufactured film even when the discharge amount of a film solution from a casting die is changed for altering the grade, in a solution film manufacturing method for cellulose ester film. SOLUTION: A dope stored in a stock tank 3 is sent to a continuous filter 5 using a metering pump 4 and filtered there. In this case, the flow rate at which the dope is sent to the filter 5 by the pump 4 is set to be a maximum flow rate (a flow rate to be used when the thick film is manufactured) at which the dope is discharged from the casting die. Under this state, a part of the dope sent from the filter 5 is fed back to the stock tank 3 through a feedback pipe 8 by means of a feedback pump 9, and the remainder of the dope is sent to the casting die 7. During this operation, the flow rate at which the dope is fed back by means of the feedback pump 9 is set so that the flow rate at which the dope is sent to the casting die 7 is equal to a flow rate at which the thin film is manufactured. |
