COEXTRUSION TRANSPARENT BIAXIALLY ORIENTED POLYESTER FILM, ITS MANUFACTURING METHOD AND LID MATERIAL FOR TRAY COMPRISING THE FILM

摘要

PROBLEM TO BE SOLVED: To provide a coextrusion transparent biaxially oriented polyester film having good heat-sealing characteristics and easy peel characteristics and suitably usable as a lid material for a tray comprising an amorphous PET layer and a crystalline PET layer.

SOLUTION: The coextrusion transparent biaxially oriented polyester film comprising a base layer B and a heat-sealable outer layer A is characterized in that (1) the outer layer A can be peeled from the amorphous PET layer after it is heat-sealed to the amorphous PET layer of the tray comprising the amorphous PET layer and the crystalline PET layer, (2) it contains 50-95 wt.% of a polyester (a) and 5-40 wt.% of a polymer (b) incompatible with the polyester and (3) it has a thickness (dA) of 1.3-3.0 μm. The polyester (a) is composed of 20-95 mol% of at least one unit derived from an aromatic dicarboxylic acid and 5-80 mol% of at least one unit derived from an aliphatic dicarboxylic acid.

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