POLYESTER FILM AND MANUFACTURING METHOD OF THE SAME

摘要

PURPOSE: A polyester film and a preparation method thereof are provided to obtain a constant haze value on the whole surface of the film and to offer a biaxially oriented polyester film to make the film itself have light diffusion property. CONSTITUTION: A polyester film comprises a polyester polymer base layer having a superficial layer on both sides of the base layer. The polyester polymer base layer except for the superficial layer has a polyester resin having a melting point of Tm1 as a matrix. The superficial layer includes optical diffusion particles which are dispersed on a transparent resin matrix. The transparent resin matrix comprises homopolyester resin 20 - 80 weight% and copolymer resin 20 -80 weight%. The upper and lower sides of the polyester film have a projecting shape when observing a cross-sectional side of the polyester film using SEM.