| 摘要 |
A polymeric film comprising a first layer which comprises (a) a mixture comprising 50-99.9% by weight polyethylene terephthalate (PET) and 0.1-50% by weight of polyethylene naphthalate (PEN) or (b) a copolymer comprising 50-99.9% by weight ethylene terephthalate units and 0.1-50% by weight ethylene naphthalate units, based on the total weight of the first layer, further comprising a second layer comprising PEN and a third layer comprising PEN, and further comprising a first intermediate layer and a second intermediate layer, wherein each of said intermediate layers comprises (a) a mixture comprising 50-99.9% by weight polyethylene terephthalate (PET) and 0.1-50% by weight polyethylene naphthalate (PEN) or (b) a copolymer comprising 50-99.9% by weight ethylene terephthalate units and 0.1-50% by weight ethylene naphthalate units, based on the total weight of the layer, and wherein the first intermediate layer is interposed between the first and second layers and the second intermediate layer is interposed between the first and third layers. The invention further relates to a method of producing such a polymeric film. The polymeric film can be used as insulation in an electric motor or generator and in a magnetic medium or in packaging material.
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