Patent ID: 7960028

Claim:
A heat-shrinkable polyester film comprising an easily slipping layer, wherein the easily slipping layer comprises a lubricant, a binder resin, and a sulfonic acid component, and the lubricant is at least one selected from the group consisting of paraffin wax, microcrystalline wax, polypropylene wax, polyethylene wax, ethylene-acrylic wax, stearic acid, behenic acid, 12-hydroxystearic acid, stearic acid amide, oleic acid amide, erucic acid amide, methylene bis(stearic acid amide), ethylene bis(stearic acid amide), ethylene bis(oleic acid amide), butyl stearate, stearic acid monoglyceride, pentaerythritol tetrastearate, cured castor oil, stearyl stearate, siloxane, stearyl alcohol, calcium stearate, zinc stearate, magnesium stearate and lead stearate, the deposition amount of the easily slipping layer is 0.002 to 0.02 g/m 2 , the easily slipping layer containing the lubricant component 10 to 60% by weight in 100% by weight of the layer is provided on an easily slipping face, the easily slipping layer contains a polyester type resin or a polyurethane resin as the binder resin, the film has a shrinkage ratio 50% or higher in the main shrinkage direction when being immersed in hot water at 95° C. for 10 seconds, the film has a dynamic friction coefficient of at least one face with one face of another film of μd<0.27 and range R<0.05, and a weight loss per unit surface area of the treated part of less than 0.24 g/m 2 after 10 reciprocation times when the film is subjected to reciprocating abrasion treatment under conditions of 30 reciprocation times/min in 100 mm reciprocating distance with 400 g load using a color fastness rubbing tester comprising a friction element having surface radius 45 mm; arc 50 mm; and width 25 mm, to which two sheets of gauze and a sand paper with #1000 particle diameter are attached in a manner that the sand paper is set in the front face side while the film sample is set on a sample stand having surface radius 200 mm in a manner that the face having a smaller friction coefficient is set in the front face side.