Thermoplastic film with good interply adhesion
AssigneeCryovac, Inc.
InventorsGRAHAM R. PIPER, RAM K. RAMESH
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Abstract
A multilayer film including an outer layer that includes a homo- or interpolymer of propylene and, directly adhered to the outer layer, a layer that includes a homogeneous ethylene/&agr;-olefin interpolymer having a density of no more than about 0.91 g/cm 3 exhibits good seal strength and good adhesion between the two layers, even in areas where the film is sealed, even after the film is oriented, even when the film is subjected to the elevated temperatures involved in cook-in procedures, and even where the film is subjected to, e.g., grease from fatty foods. The film also can include one or more, for example, bulk layers, O 2-barrier layers, and/or abuse layers.
Claims20
A multilayer film comprising:
- a) an outer layer which comprises a polymer comprising mer units derived from propylene;
- and
- b) directly adhered to said outer layer, a second layer comprising a homogeneous ethylene/α-olefin interpolymer having a density of no more than about 0.915 g/cm3,
- said film being oriented and, optionally, having been subjected to irradiation.
An oriented multilayer film comprising:
- a) a first outer layer comprising a polymer comprising mer units derived from propylene;
- b) a second outer layer;
- and
- disposed between said first and second outer layers,
- c) a first inner layer comprising a homogeneous ethylene/α-olefin interpolymer having a density of no more than about 0.915 g/cm3, said first inner layer being directly adhered to said first outer layer;
- d) a second inner layer comprising a polymer with a low permeance to oxygen;
- and
- e) a third inner layer,
- said second inner layer being disposed between said first and third inner layers, said film optionally further comprising one or both of a tie layer between said first and second inner layers and a tie layer between said second and third inner layers.
Dependencies are inferred from the claim text.