| 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 simultaneously-biaxially-stretched PBT film that has almost no anisotropy and has superior gas barrier properties, mechanical properties and dimensional stability.SOLUTION: Preferably, a biaxially-stretched polybutylene terephthalate (PBT) film having gas barrier properties is provided such that the tensile breaking strength in all four directions is ≥200 MPa, the tensile elongation at break is ≥50% and ≤150%, and a coating layer having oxygen barrier properties is applied to at least one surface. Such a film is stably obtained by subjecting an extruded PBT resin melt to a 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 3.0-4.0 times. |
