| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a biaxially oriented polyamide resin film tough and excellent in pinhole resistance, lamination properties and appearance without curling, delamination (delamination phenomenon) of a laminate film, etc. even if subjected to boiling water, having excellent performance as a packaging material, especially, a packaging bag for retort pouch foods. SOLUTION: In the manufacture of the biaxially oriented polyamide resin film, a substantially unoriented polyamide resin film or sheet is stretched in longitudinal/lateral directions with a stretch retio of 3 or more. In a longitudinal stretching process, the film is stretched in at least two stages at a temperature higher than a temperature of the glass-transition temperature of a polyamide resin plus 20°C and as high as/lower than a temperature of a cold-crystallization temperature plus 20°C. The biaxially oriented polyamide resin film satisfies 3%≤BSx≤6% (BSx represents a maximum value among percentages of omnidirectional boiling water contraction) and BSa≤1.5% (BSa represents the absolute value of a difference between the percentage of priming contraction in the direction of an angle of +45°with respect to the longitudinal direction and the percentage of boiling water contraction in the direction of an angle of -45°with respect to the longitudinal direction). COPYRIGHT: (C)2004,JPO&NCIPI |
