Biaxially oriented laminate polyester film
AssigneeTeijin Limited
InventorsIeyasu Kobayashi, Toshifumi Osawa
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Abstract
A biaxially oriented laminate polyester film (1) has a first polyester layer having a thickness (tA) of 0.3 to 5 μm and a second polyester layer containing an inert fine particle lubricant and having a thickness (tB) of 1.5 to 9 μm, or (2) has a first polyester layer having a thickness (tA) of 2 to 8.5 μm and a second polyester layer containing an inert fine particle lubricant and having a thickness (tB) of 0.6 to 5 μm. The polyester of the second polyester layer may contain a recovered polyester having the same composition as a recovered laminate polyester film which is the biaxially oriented laminate polyester film or an unstretched film thereof.
Claims15
A biaxially oriented laminate polyester film comprising a first polyester layer and a second polyester layer, wherein
- the first polyester layer has a thickness (tA) of 0.3 to 5 μm, the second polyester layer contains an inert fine particle lubricant and has a thickness (tB) of 1.5 to 9 μm, and the first polyester layer and the second polyester layer satisfy the following expressions (1) to (4):
- WRa(B)>WRa(A) (1)
- 0.5≦tB/t≦0.9 (2)
- 10<tB/dB≦60 (3)
- t=3 to 10 μm (4)
- wherein WRa(A) is the center plane average roughness (nm) of the exposed surface of the first polyester layer, WRa(B) is the center plane average roughness (nm) of the exposed surface of the second polyester layer, tB is the thickness (μm) of the second polyester layer, t is the sum of tA and tB, tA is the thickness (μm) of the first polyester layer, and dB is the average particle diameter (μm) of the inert fine particle lubricant contained in the second polyester layer.
Dependencies are inferred from the claim text.