| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an easily stretchable polyester film that cannot be stretched with a low stress at a temperature around 80°C but can be stretched with a low stress at a temperature around 130°C.SOLUTION: The easily stretchable polyester film is a film made of a polyester having: a dicarboxylic acid structural unit that contains 95 to 87 mol% of a terephthalic acid unit and 5 to 13 mol% of an isophthalic acid unit; and a glycol structural unit mainly comprising an ethylene glycol unit. The film has a 5%-elongation stress (F5 value) at 130°C in a range of from 4 to 15 MPa in the MD of the film, an F5 value at 80°C of 30 MPa or more in the MD of the film, and a shrinkage by heating at 150°C for 3 minutes in a range of from 0.0 to 2.0% in the MD of the film.</p> |
