| abstract |
To provide a layered polyester film having at least polyester layers A and B, wherein the layered polyester film is a white polyester film having exceptional heat dissipation performance and light reflectivity, layer B is a white layer containing fine bubbles and/or inorganic particles, and layer A forms the outermost layer of at least one side of the layered polyester film and contains inorganic particles. The inorganic particles satisfy all of the following: (a) the thermal diffusivity is 100 × 10 -7 m 2 /s or above; (b) the inorganic particles are contained at an amount of 2.0 vol% to 40.0 vol% with respect to the total polyester resin composition constituting layer A; (c) the frequency distribution of the particle diameter has two peaks at D1 (μm) and D2 (μm), which satisfy all of 1.0 ≤ D1 ≤ 10, 0.2 ≤ D2 ≤ 3.5, and D1/D2 ≥ 2; (d) where the frequency distributions at D1 and D2 are F(D1)(%) and F(D2)(%) respectively, F(D2)/F(D1) ≥ 2.0 is satisfied; and (e) when the number average particle diameter in layer A is D μm, D2 < D < D1, and the frequency distribution F(D) of the particle diameter D μm satisfies 0 ≤ F(D) < F(D1). |