| 摘要 |
PROBLEM TO BE SOLVED: To stably manufacture a film having characteristics suitable for a converting film, a food packaging film, and a drawing film, that is, a biaxially-stretched PBT film that has almost no anisotropy and is excellent in mechanical properties and dimensional stability.SOLUTION: A biaxially-stretched polybutylene terephthalate (PBT) film is provided such that the tensile breaking strength in all four directions is ≥200 MPa and the tensile elongation at break is ≥50% and ≤150%. The film is suitably used as a food packaging film, a drawing film, and a converting film. Such a film is stably obtained by subjecting extruded PBT resin melt to quench film-formation at a very high cooling speed of ≥200°C/second and simultaneously biaxially stretching it in the longitudinal and lateral directions respectively to 2.7-4.0 times. |
