| abstract |
PURPOSE:To prepare a heat-shrinkable polyester film having an excellent heat shrinkability in a specific direction at a low temp. by forming a polyester copolymer comprising a dicarboxylic acid component mainly comprising a terephthalic acid and a specific diol component into a film and orienting the film at about the glass transition temp. CONSTITUTION:A film is formed from a polyester copolymer comprising: a dicarboxylic acid component comprising terephthalic acid (deriv.); and a diol component comprising 50-90mol% ethylene glycol, 5-50mol% neopentyl glycol, and 3-20mol% glycol selected from the group consisting of diethylene glycol, triethylene glycol, and a polyethylene glycol. The resulting film is oriented at about the glass transition temp. to give a heat-shrinkable polyester film, which has a shrinkage in one direction after heated in a glycerin bath for 30sec at 70 deg.C, 80 deg.C, and 90 deg.C of 20% or higher, 30% or higher, and 40% or higher, respectively, has a shrinkage in the direction transverse to above-mentioned direction at 0-100 deg.C of lower than 10%, and is suitable for a shrinkable label, etc. |