Patent ID: 10766237

Abstract:
The polyester film is formed with a polyester resin whose main constituent component is ethylene terephthalate. The polyester film has two or more layers that include at least one fold holding layer, which is present on at least one of the film surfaces and has a total of at least one monomer component that can form an amorphous component of 12-30% by mol in all monomer components of the fold holding layer and a difference in amount of an amorphous component of 4-30% by mol obtained by deducting an amount of an amorphous component in a layer other than the fold holding layer from the amount of the amorphous component in the fold holding layer. The polyester film has a fold holding angle of 20-70 degrees and a heat shrinkage rate of 0-15% in the longitudinal and width directions when treated in 80° C. hot water for 10 seconds.