Patent ID: 8029909

Claim:
A multilayer film, comprising a structure where five or more layers made of thermoplastic resin A (layers A) and five or more layers made of thermoplastic resin B (layers B) having a basic skeleton that is the same as that of thermoplastic resin A are alternately layered on top of each other, wherein at least one reflection peak is provided and the difference between the reflectance of the reflection peak before heating and after heating for 30 minutes in an atmosphere of 150° C. is no greater than 15%, wherein the total number of layers A and layers B is no less than 640, and wherein the difference in reflectance between the peaks of reflection in different locations in the direction of the width of the film is within ±10%, and wherein the multilayer film is manufactured by using a feedblock which separately includes at least two or more members having a number of microscopic slits, and wherein thermoplastic resin A is polyethylene terephthalate and thermoplastic resin B is a resin formed from polyethylene terephthalate and copolymerized cyclohexane dimethanol such that the polyethylene terephthalate is compounded at a ratio of 50:50 to 99:1 in the resin.