LAMINATED POLYESTER FILM AND PRODUCTION METHOD THEREOF

To provide a laminated polyester film provided with an antireflection layer with both antifouling property and low reflectivity.SOLUTION: Provided is a laminated polyester film having an antireflection layer on either surface of a polyester film, in which the antireflection layer is formed of a resin composition comprising two kinds of resin components having different refractive indexes, one resin component (A) of the two kinds of resin components contains a fluorine-based resin, a refractive index of the other resin component (B) of the two kinds of resin components is higher than that of the fluorine-based resin, and when sequential argon (Ar) etching and XPS (X-ray photoelectron spectroscopy) are used to measure concentration distributions of fluorine atoms (F) and oxygen atoms (O) in the thickness direction of the antireflection layer and when the first time at which the amount of the fluorine atoms (F) becomes less than the amount of oxygen atoms (O) is assumed to be X seconds and the amount of fluorine atoms (F) at an etching time of 0 second is assumed to be 100, the amount of fluorine atoms (F) at 1.5X seconds is 10 to 20.SELECTED DRAWING: None 【課題】本発明の目的は、防汚性及び低反射性を兼備する反射防止層を備えた、積層ポリエステルフィルムを提供することにある。【解決手段】ポリエステルフィルムの少なくとも一方の面に反射防止層を有し、前記反射防止層は、屈折率の異なる２種の樹脂成分を含む樹脂組成物から形成され、前記２種の樹脂成分のうちの一方の樹脂成分（Ａ）が、フッ素系樹脂を含み、前記２種の樹脂成分のうちの他方の樹脂成分（Ｂ）の屈折率が前記フッ素系樹脂よりも高く、逐次アルゴン（Ａｒ）エッチングとＸＰＳ（Ｘ線光電子分光法）を用いて、前記反射防止層の厚み方向におけるフッ素原子（Ｆ）及び酸素原子（Ｏ）の濃度分布を測定し、前記フッ素原子（Ｆ）量が酸素原子（Ｏ）量より少なくなる最初の時間をＸ秒とし、エッチング０秒時のフッ素原子（Ｆ）量を１００としたとき、１．５Ｘ秒時のフッ素原子（Ｆ）量が１０以上２０以下である、積層ポリエステルフィルム。【選択図】なし