| 摘要 |
PURPOSE:To improve drastically gas barrier properties in case of metallizing of a metal such as aluminum, by a method wherein the title film is of a biaxially oriented film of thermotropic crystalline polyester having a mold ratio of a specific structural unit and mean surface roughness of a widthwise direction and a ratio between the Young's moduli of a longitudinal direction and widthwise direction of at least one surface are specified. CONSTITUTION:The title film is of a biaxially oriented film of thermotropic crystalline polyester where a structural unit is constituted of formulas (I) to (IV), a structural unit [(I)+(II)] is 55-95 mol% of [(I)+(II)+(III)], a structural unit (III) is 45-5 mol% of the [(I)+(II)+(III)] and a mol ratio of the structural unit (I)/(III) is 75/25-95/5. Mean surface roughness Ra of a widthwise direction is 3-50 nm and ratio between the Young's moduli of lengthwise direction and widthwise direction is 10:1-1:3 on at least one surface. The structural unit (I) is a structural unit formed of p-hydroxy benzoic acid, the structural unit (II) is a structural unit formed of 4, 4'-dihydroxy biphenyl and the structural unit (III) is a structural unit formed of ethylene glycol. Then the structural unit (IV) is a structural unit of polyester formed of aromatic dicarboxylic acid selected out of terephthalic acid and isophthalic acid. |
