| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical film of an acrylic resin whose backbone chain has a ring structure by fusion-molding using an extruder, capable of ensuring smooth resin switchover, facilitating confirming the completion of the switchover between compatible resins, and ensuring high adaptability to drawing after the fusion-molding.SOLUTION: A method comprises a switching step, in which the supply of a thermoplastic resin different from first and second acrylic resins to an extruder fusion-molding an optical film of the first acrylic resin starts, the supply of the second resin starts and the supply of the first resin stops after starting the supply of the thermoplastic resin, and the supply of the thermoplastic resin stops after starting the supply of the second resin, the thermoplastic resin being either a resin A incompatible with at least one resin selected from the first and second resins or a resin B compatible with both of the first resin and the second resin and different in birefringence characteristics from the at least one resin selected from the first and second resins.</p> |
