5-layer barrier film, sealing process and use thereof for packaging food
AssigneeBollore
InventorJosyane Bonetti
Life of this patent
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Abstract
The invention relates to a barrier film made up of five stacked layers comprising: a central barrier layer comprising a first blend of EVOH and of PA, two outer layers comprising a second blend, and two adhesive layers between the central layer and the two outer layers, wherein the second blend only contains a first copolymer of ethylene and of an a-olefin having a density less than or equal to 0.925 g/cm3 and greater than or equal to 0.915 g/cm3 and a second metallocene copolymer of ethylene and of an a-olefin having a density less than or equal to 0.910 g/cm3.
Claims25
A barrier film comprising five superposed layers, comprising:
- a central barrier layer comprising a first blend of an ethylene-vinyl alcohol copolymer in majority by weight and of polyamide;
- two outer layers comprising a second blend of copolymers of ethylene and α olefins;
- and
- two adhesive layers between the central layer and the two outer layers, respectively;
- characterized in that:
- the second blend of copolymers of ethylene and α-olefins of at least one of the outer layers, only contains a first copolymer of ethylene and of an α-olefin having a density less than or equal to 0.925 g/cm3, and greater than or equal to 0.915 g/cm3, and a second metallocene copolymer of ethylene and of an α-olefin having a density less than or equal to 0.910 g/cm3;
- the proportions of the second copolymer relative to the weight of its outer layer being greater than or equal to 20% and less than or equal to 45%;
- the seal initiation temperature for a sealing breaking force greater than or equal to 15 N/30 mm being lower than 120° C.;
- and
- the seal breaking force of the film being greater than or equal to 10 N/30 mm after passing in a water bath for one hour and a half at 85° C.
A method for sealing at least two walls of a package comprising:
- applying on the walls at least one heating protruding element for their sealing, characterized in that the temperature of the heating protruding element is less than or equal to 130° C.;
- wherein the at least two walls of the package are made up of a barrier film comprising five superposed layers, comprising:
- a central barrier layer comprising a first blend of an ethylene-vinyl alcohol copolymer in majority by weight and of polyamide;
- two outer layers comprising a second blend of copolymers of ethylene and α-olefins;
- and
- two adhesive layers between the central layer and the two outer layers, respectively;
- wherein:
- the second blend of copolymers of ethylene and α-olefins of at least one of the outer layers, only contains a first copolymer of ethylene and of an α-olefin having a density less than or equal to 0.925 g/cm3, and greater than or equal to 0.915 g/cm3, and a second metallocene copolymer of ethylene and of an α-olefin having a density less than or equal to 0.910 g/cm3;
- the proportions of the second copolymer relative to the weight of its outer layer being greater than or equal to 20% and less than or equal to 45%;
- the seal initiation temperature for a sealing breaking force greater than or equal to 15 N/30 mm being lower than 120° C.;
- and
- the seal breaking force of the film being greater than or equal to 10 N/30 mm after passing in a water bath for one hour and a half at 85° C.
Dependencies are inferred from the claim text.