FLAME RETARDANT BIAXIALLY ORIENTED POLYESTER FILM FOR FLEXIBLE CIRCUIT BOARD, AND FLEXIBLE CIRCUIT BOARD INCLUDING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide: a flame retardant biaxially oriented polyester film for a flexible circuit board, which can be suitably used as an FPC circuit board superior in flame retardancy and surface flatness; and a flexible circuit board including such a flame retardant biaxially oriented polyester film.SOLUTION: A flame retardant biaxially oriented polyester film for a flexible circuit board comprises a layer A including 70-99.5 wt% of polyethylene naphthalene dicarboxylate, and 0.5-30 wt% of flame retardant particles expressed by a particular phosphinate or diphosphinate and having an average particle diameter of 0.5-3.0 μm. The number of coarse particles of 10 μm or larger in maximum length, which is included in the layer A is 10/mor less.SELECTED DRAWING: None