COEXTRUSION TRANSPARENT BIAXIALLY ORIENTED POLYESTER FILM, AND 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 to medium 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 heat-sealed to and peeled from the amorphous PET layer, (2) it contains 80-98 wt.% of a polyester (a) and 2-10 wt.% of inorganic and/or organic particles with an average particle size d50of 2.5-8.0 μm and (3) it has a thickness dAof 1.0-5.0 μm. The polyester (a) is composed of 12-89 mol% of at least one unit derived from an aromatic dicarboxylic acid and 11-88 mol% of at least one unit derived from an aliphatic dicarboxylic acid and the ratio d50/dAof the average particle size d50of the particles and the thickness dAof the outer layer A is larger than 1.2.

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