FLAME-RETARDANT BIAXIALLY-ORIENTED POLYESTER FILM, AND FLAME-RETARDANT POLYESTER FILM LAYERED BODY AND FLEXIBLE CIRCUIT BOARD COMPRISING SAME

摘要

The purpose of the present invention is to provide the following: a flame-retardant biaxially-oriented polyester film in which the polyester film itself is made flame-retardant by a phosphorous-based flame retardant, the decrease in hydrolysis resistance of the polyester film due to the phosphorous-based flame retardant is suppressed, and the decrease in film-forming properties and the decrease in mechanical characteristics due to the phosphorous-based flame retardant are suppressed; and a flame-retardant polyester film layered body and a flexible circuit board each comprising such a flame-retardant biaxially-oriented polyester film. The present invention is obtained using a flame-retardant biaxially-oriented polyester film that comprises, with respect to the weight of the polyester film, 70-99.5% by weight of polyethylene terephthalate or polyethylene naphthalate and 0.5-30% by weight of flame-retardant particles represented by specific phosphinates or diphoshinates and having a mean particle diameter of 0.5-3.0 µm, and in which the number of coarse particles with a maximum length of 10 µm or more included in the polyester film is 10 particles/m2 or less.