| 摘要 |
PROBLEM TO BE SOLVED: To provide a foreign matter removing method in which melt viscosity of a thermoplastic resin can be reduced with a simple device and filtering accuracy of a filter can be sufficiently improved, and to provide a method for producing an optical film using the method. SOLUTION: The foreign matter removing method comprises passing a molten resin mixture containing an imidized acrylic resin through a filter to remove foreign matter contained in the resin mixture. The resin mixture contains at least one component selected from the group consisting of methanol, monomethylamine, dimethylamine, and trimethylamine. The component is either a by-product produced in the process of imidization reaction of an acrylic resin with an imidization agent or an unreacted material from the imidization reaction. The resin mixture contains 5 pts.wt. or more of the component based on 100 pts.wt. of the imidized acrylic resin. COPYRIGHT: (C)2009,JPO&INPIT
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