MULTILAYER FILM

摘要

The present invention provides a multilayer film which reflects light within a specific band, and which is free from the problem of delamination that occurs in cases where a polyethylene naphthalate resin is used therefor. A multilayer film which has 201 or more layers obtained by alternately laminating layers A that are formed of a polyester A containing ethylene-2,6-naphthalate as a main repeating unit and layers B that are formed of a polyester B containing ethylene terephthalate as a main repeating unit and having a refractive index lower than that of the polyester constituting the layers A. This multilayer film is characterized in that the polyester A satisfies the following requirements. (1) The amount of terminal carboxylic acid groups is from 5 eq/t to 20 eq/t (inclusive). (2) An alkali metal phosphate salt is contained in an amount of from 1.3 mol/ton to 3.0 mol/ton (inclusive), and phosphoric acid is contained at a molar ratio of from 0.4 times to 1.5 times (inclusive) relative to the alkali metal phosphate salt. (3) The intrinsic viscosity is from 0.55 to 0.63 (inclusive).