Multilayer monoaxially oriented film
The present invention is directed to a monoaxially oriented multilayer film suitable for shrink lidding applications.
1 . A monoaxially oriented, crosslinked film consisting of:
a first outer layer;
a second outer layer;
an oxygen barrier layer, wherein the oxygen barrier layer consists of polyamide and/or EVOH;
adjacent layers between the first outer layer and the oxygen barrier layer and between the second outer layer and the oxygen barrier layer, wherein each of the adjacent layers consists of one or more materials selected from the group consisting of an ethylene alpha olefin copolymer, a low density polyethylene, a high density polyethylene, an ionomer, a maleic anhydride grafted polyethylene, a maleic anhydride grafted polypropylene, an ethylene vinyl acetate, a polyamide, and a polyester; and
an abuse layer, wherein the abuse layer is located between and in direct contact with both the oxygen barrier layer and an adjacent layer, wherein the abuse layer consists of an ethylene alpha olefin copolymer, a low density polyethylene, a high density polyethylene, an ionomer, a maleic anhydride grafted polyethylene, a maleic anhydride grafted polypropylene, an ethylene vinyl acetate, a polyamide, and a polyester;
wherein the film has a shrinkage in the MD direction in a range from 1 to 30% measured according to ASTM D2732 by immersion in water at a temperature of 90° C. and an immersion time of 5 seconds; and wherein the film consists of the following layers:
OUTER LAYER 1/ADJACENT LAYER 1/ADJACENT LAYER 2/ADJACENT LAYER 3/OXYGEN BARRIER LAYER/ABUSE LAYER/ADJACENT LAYER 4/ADJACENT LAYER 5/OUTER LAYER 2.
2 . The film according to claim 1 , wherein the oxygen barrier layer consists of EVOH.
3 . The film according to claim 1 , wherein the film has a shrinkage in the MD direction in a range from 5 to 20% measured according to ASTM D2732 by immersion in water at a temperature of 90° C. and an immersion time of 5 seconds.
4 . The film according to claim 1 , wherein the first outer layer comprises a component selected from the group consisting of ethylene alpha olefin copolymers, low density polyethylene, high density polyethylene, ionomers, thermoplastic adhesives, cyclic olefin copolymers, ethylene vinyl acetates, polyamides, and polyesters.
5 . The film according to claim 1 , wherein the second outer layer comprises at least one component selected from the group consisting of ethylene alpha olefin copolymers, low density polyethylene, high density polyethylene, ionomers, thermoplastic adhesives, cyclic olefin copolymers, ethylene vinyl acetates, polyamides, and polyesters.
6 . The film according to claim 1 , wherein the oxygen barrier layer consists of a blend of an amorphous polyamide with one or more other polyamides.
7 . The film according to claim 1 , wherein the first outer layer and the second outer layer independently comprise a component selected from the group consisting of ethylene alpha olefin copolymers, low density polyethylene, high density polyethylene, ionomers, thermoplastic adhesives, cyclic olefin copolymers, ethylene vinyl acetates, polyamides, and polyesters.
8 . The film according to claim 1 , wherein the film comprises an antifog compound.
9 . A method for modified atmosphere packaging (MAP), the method comprising sealing a food item in a package, the package comprising a tray on which the food is placed and a top lidding film, wherein the top lidding film comprises the monoaxially oriented, crosslinked film of claim 1 .
10 . A pack comprising a film according to claim 1 and a tray.
11 . The film according to claim 4 , wherein the first outer layer comprises an ethylene alpha olefin copolymer.
12 . The film according to claim 6 , wherein the amorphous polyamide is present in the oxygen barrier layer in an amount of 10-40% per mass of the polyamide blend.
13 . The film according to claim 6 , wherein the amorphous polyamide is 6I/6T.
14 . The film according to claim 1 , wherein each of the adjacent layers consist of (i) polyamide, (ii) linear low density polyethylene (LLDPE), or (iii) LLDPE and low density polyethylene; and wherein the abuse layer consists of a polyamide or LLDPE.
15 . The film according to claim 14 , wherein each of the adjacent layers consists of LLDPE or LLDPE and low density polyethylene.