Transparent gas barrier biaxially oriented polypropylene film, a laminate film, and a production method thereof
First Claim
1. A transparent gas barrier biaxially oriented polypropylene film, comprising:
- 1) a base layer comprising a polypropylene polymer2) a polyolefin resin layer of 30 to 85 J/g in the heat of fusion formed at least on one side of the base layer, and3) an imperfectly oxidized alumina layer formed on the polyolefin resin layer, wherein the aluminum metal concentration in the internal portion of the imperfectly oxidized alumina layer is higher than that in the surface of the layer and that in the interface with the polyolefin resin layer, and the aluminum metal content in the imperfectly oxidized alumina layer is kept in a range of 10 to 200% nm.
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Abstract
A transparent gas barrier biaxially oriented polypropylene film, comprising a base layer mainly composed of a polypropylene polymer, a polyolefin resin layer of 30 to 85 J/g in the heat of fusion formed at least on one side of the base layer, and an imperfectly oxidized alumina layer formed on the polyolefin resin layer, wherein the aluminum metal concentration in the internal portion of the imperfectly oxidized alumina layer is higher than that in the surface of the layer and that in the interface with the polyolefin resin layer, and the aluminum metal content of the imperfectly oxidized alumina layer is kept in a range of 10 to 200% nm. It is a transparent metallized gas barrier biaxially oriented polypropylene film excellent in moisture and oxygen barrier properties and also excellent in the gas barrier properties after elongation.
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Citations
11 Claims
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1. A transparent gas barrier biaxially oriented polypropylene film, comprising:
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1) a base layer comprising a polypropylene polymer 2) a polyolefin resin layer of 30 to 85 J/g in the heat of fusion formed at least on one side of the base layer, and 3) an imperfectly oxidized alumina layer formed on the polyolefin resin layer, wherein the aluminum metal concentration in the internal portion of the imperfectly oxidized alumina layer is higher than that in the surface of the layer and that in the interface with the polyolefin resin layer, and the aluminum metal content in the imperfectly oxidized alumina layer is kept in a range of 10 to 200% nm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for producing a transparent gas barrier biaxially oriented polypropylene film, in which an imperfectly oxidized alumina layer is continuously formed on a polyolefin resin substrate consisting of 1) a base layer comprising a polypropylene polymer and 2) a polyolefin resin layer of 30 to 85 J/g in the heat of fusion formed at least on one side of the base layer, by reactively evaporating metal aluminum with an oxidizing gas, comprising the steps of introducing the oxidizing gas below the substrate with its distance from the substrate kept at 1/4 or less of the distance between the evaporation source and the substrate, from the side where the substrate goes into the area for receiving the evaporated aluminum, with the concentration of the oxidizing gas changed in the progression direction of the substrate, to change the concentration of aluminum metal vapor-deposited in the thickness direction of the vapor-deposited layer;
- and exposing the imperfectly oxidized alumina layer to atmospheric air, for aging.
Specification