| abstract |
(57) Abstract: [PROBLEMS] To provide a polyester-based composite film having good gas barrier properties. According to the present invention, at least one of two surfaces of a polyester base film having a thickness of 5 μm to 50 μm is coated with a layer of polyvinyl alcohol having a thickness of 0.3 μm or less at 23 ° C. and a relative humidity of 50. characterized in that it presents a to 3cm 3 / m 2/24 hours or less of oxygen permeability measured in%, related to biaxially oriented composite film having improved gas barrier properties as a base material of polyester. In addition to transparency and barrier properties, the composite film of the present invention exhibits excellent resistance to mechanical attack, especially creases. Further, since the composite film has a low polyvinyl alcohol content as a whole, it can be easily recycled. |