| abstract |
An object of the present invention is that the polyester film itself is flame-retardant with a phosphorus-based flame retardant, the decrease in hydrolysis resistance of the polyester film by these flame retardants is suppressed, and the film-manufactureability decrease and mechanical properties decrease by the flame retardant To provide a flame-retardant biaxially oriented polyester film with suppressed flame retardancy, a flame-retardant polyester film laminate comprising the same, and a flexible circuit board. The present invention relates to a flame retardant particle having an average particle diameter of 0.5 to 3.0 µm represented by 70% by weight or more and 99.5% by weight or less of polyethylene terephthalate or polyethylenenaphthalate based on the weight of the polyester film, and a specific phosphinate or diphosphinate. It is obtained with a flame-retardant biaxially oriented polyester film containing 0.5% by weight or more and 30% by weight or less, and the number of coarse particles having a maximum length of 10 µm or more contained in the polyester film is 10 pieces/m 2 or less. |