Patent ID: 7303812

Claim:
A heat-shrinkable multi-layered polyester film made of a polyester resin and comprising a three-layer A/B/A structure, wherein layer B is a void containing layer and layers A are layers having no voids, and wherein the film has a total luminous transmittance of not more than 40%, a haze of not less than 90%, a heat shrinkage percentage of not less than 50% in a maximum shrinkage direction and a heat shrinkage percentage of not more than 10% in a direction orthogonal to the maximum shrinkage direction as determined by cutting a square sample in a size of 10 cm×10 cm off from the film, immersing the square sample film in hot water at 95° C. for 10 seconds, subsequently in water at 25° C. for 10 seconds, and withdrawing the square sample film from the water, the film has a heat shrinkage percentage of 65% or more in the maximum shrinkage direction and a heat shrinkage percentage of not more than 2% in the direction orthogonal to the maximum shrinkage direction as determined by cutting a square sample in a size of 10 cm×10 cm off from the film, immersing the square sample film in hot water at 80° C. for 10 seconds, subsequently in water at 25° C. for 10 seconds, and withdrawing the square sample film from the water, and the A/B/A structure has a thickness ratio for the three layers in the range of 25/50/25 to 10/80/10, wherein the film has a solvent adhesion strength of not less than 4N/15 mm.