Patent ID: 8722161

Claim:
A heat shrinkable polyester film made of a polyester resin comprising 50% by mole or more of ethylene terephthalate and containing 3% to 12% by mol of at least one monomer capable of forming an amorphous component in the whole components of the polyester resin, wherein the heat shrinkable polyester film has a main shrinkage direction which is the width direction, and wherein the heat shrinkable polyester film satisfies the following requirements (1) to (4): (1) glycerin shrinkage in the longitudinal direction and the width direction is 2% or less when being treated in glycerin at 80° C. for 10 seconds; (2) glycerin shrinkage in the longitudinal direction is 0% or more and 10% or less when being treated in glycerin at 130° C. for 10 seconds; (3) glycerin shrinkage in the width direction is 25% or more and 60% or less when being treated in glycerin at 130° C. for 10 seconds; and (4) tensile breaking strength in the longitudinal direction is 50 MPa or more and 130 MPa or less.