Transparent polyester film with enhanced water vapor barrier, its production and use
AssigneeMitsubishi Polyester Film GmbH
InventorsHerbert Peiffer, Gottfried Hilkert
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Abstract
Transparent, multilayer, biaxially oriented polyester films having a) a base layer B composed of at least 50% by weight of a thermoplastic polyester and from 0 to 30% by weight of a cycloolefin copolymer and b) an outer layer composed of from 20 to 100% by weight of a cycloolefin copolymer, the glass transition temperature of the cycloolefin copolymers being less than 120° C., possess very good water vapor barrier properties and effective adhesion between the layers. These films are especially suitable for packaging foods and other consumables.
Claims18
A multilayer, transparent, biaxially oriented polyester film which has a base layer B composed of at least 50% by weight of a thermoplastic polyester, and has at least one outer layer A, wherein
- a) the base layer B comprises a fraction of from about 0 to about 30% by weight of a cycloolefin copolymer (COC),
- b) the outer layer A comprises a fraction of from about 20 to about 100% by weight of a cycloolefin copolymer (COC),
- c) the glass transition temperature Tg of the cycloolefin copolymer (COC) is below about 120° C., and
- d) the permeation coefficient of the film for water vapor is smaller than 35 gA[12 μm]/m2Ad.
Dependencies are inferred from the claim text.