Frangible heat-sealable films for cook-in applications and packages made thereof
Coextruded easy-opening film structures having at least three layers for use as a packaging film or as a component thereof suitable for storing and/or cooking food items contained therein. The first film layer includes a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer and blends thereof, the second film layer comprises a first modified or unmodified polyolefin and a second modified or unmodified polyolefin which is immiscible in the first modified or unmodified polyolefin; wherein the second layer is disposed between said first layer and said third layer. The third layer includes a material selected from the group consisting of polyethylene, anhydride-modified polyolefin; ethylene/vinyl alcohol copolymer, polyamide and blends thereof. The multilayer coextruded frangible films are thermoformable and exhibit a heat seal strength of between 1000-2500 g/in. (393.7-984.3 g/cm) after being submerged in water at 100° C. for one hour upon conducting a Standard Heat Seal Strength Test.
1. A multilayer coextruded frangible film for cook-in applications comprising;
(a) a first layer, a second layer, and a third layer;
(b) wherein said first layer comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer and blends thereof;
(c) wherein said second layer comprises a first modified or unmodified polyolefin and a second modified or unmodified polyolefin which is immiscible in said first modified or unmodified polyolefin; wherein said second layer is disposed between said first layer and said third layer;
(d) wherein said third layer comprises a material selected from the group consisting of polyethylene, anhydride-modifled polyolefin, ethylene/vinyl alcohol copolymer, polyamide and blends thereof; and
(e) wherein said second layer is adapted to peel from said first layer or said third layer under a force of between 1000-2500 g/in. (393.7-984.3 g/cm) as measured in accordance with the Standard Heat Seal Strength Test.
2. A multilayer coextruded frangible film according to claim 1 , wherein said first layer is free of polybutene copolymer and is a heat-sealable, outer-film layer.
3. A multilayer coextruded frangible film for cook-in applications comprising;
(a) a first layer, a second layer, and a third layer;
(b) wherein said first layer comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer and blends thereof;
(c) wherein said second layer comprises a first blend component; said first blend component comprises a material selected from the group consisting of polypropylene, polybutene copolymer, and blends thereof and said first blend component is immiscible with a second blend component; said second blend component comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer, ethylene/vinyl acetate copolymer, polyethylene, anhydride-modified polyolefin, ionomer, anhydride-modified ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, anhydride-modified ethylene/α-olefin copolymer, and blends thereof; wherein said second layer is disposed between said first layer and said third layer;
(d) wherein said third layer comprises a material selected from the group consisting of polyethylene, anhydride-modified polyolefin, ethylene/vinyl alcohol copolymer, polyamide and blends thereof; and
(e) wherein said second layer is adapted to peel from said first layer or said third layer under a force of between 1000-2500 g/in. (393.7-984.3 g/cm) as measured in accordance with the Standard Heat Seal Strength Test.
4. A multilayer coextruded frangible film according to claim 3 , wherein said first layer is free of polybutene copolymer and is a heat-sealable, outer-film layer.
5. A multilayer coextruded frangible film according to claim 3 , wherein said ethylene/α-olefin copolymer of said first layer has a melting point of less than 105° C. as measured in accordance with ASTM D-3418, a molecular weight distribution M w /M n of from 0.05-2.7 as measured in accordance with ASTM D-3593-80, and a melt index of from 5.0-34 g/10 min. at 190° C. as measured in accordance with ASTM D-1238 Condition 190° C./2.16 kg.
6. A multilayer coextruded frangible film according to claim 3 , wherein said anhydride-modified polyolefin comprises a maleic anhydride-grafted copolymer of between 0.05-1% by weight of maleic anhydride and between 99.95-99% by weight of polyolefin relative to the total weight of said anhydride-modified polyolefin.
7. A multilayer coextruded frangible film according to claim 3 , wherein said film has an unrestrained linear thermal shrinkage in the machine direction or the transverse direction of less than 5% at 100° C. as measured in accordance with ASTM D-2732 test method.
8. A multilayer coextruded frangible film according to claim 3 , wherein said film has an oxygen transmission rate of from about 0.01-1.00 cm 3 /100 in. 2 (0.1550-15.50 cm 3 /m 2 ) as measured in accordance with ASTM D-3985-81 test method.
9. A multilayer coextruded frangible film according to claim 3 , wherein said film is thermoformable.
10. A multilayer coextruded frangible film according to claim 3 , further comprising a fourth layer; wherein said fourth layer comprises a material selected from the group consisting of ethylene/vinyl alcohol copolymer, polyamide, polyethylene, anhydride-modified polyolefin and blends thereof.
11. A multilayer coextruded frangible film according to claim 10 , wherein said film is thermoformable.
12. A multilayer coextruded frangible film according to claim 10 , further comprising a fifth layer; wherein said fifth layer comprises a material selected from the group consisting of polyethylene, polybutene copolymer, anhydride-modified polyolefin, and blends thereof.
13. A multilayer coextruded frangible film according to claim 12 , wherein said film is thermoformable.
14. A multilayer coextruded frangible film according to claim 12 , further comprising a sixth layer; wherein said sixth layer comprises an ethylene/α-olefin copolymer.
15. A multilayer coextruded frangible film according to claim 14 , further comprising a seventh layer; wherein said seventh layer comprises an ethylene/α-olefin copolymer.
16. A multilayer coextruded frangible film according to claim 15 , wherein said film is thermoformable.
17. A multilayer coextruded frangible film according to claims 1 , 3 , 10 , 12 , or 15 , wherein said film forms a package adapted for storing and cooking food items.
18. A multilayer coextruded frangible film according to claim 17 , wherein said first layer of said film is heat sealed to itself to form said package.
19. A multilayer coextruded frangible film according to claim 17 , wherein said first layer of said film is heat sealed to a second film to form said package.
20. A multilayer coextruded frangible film according to claim 19 , wherein said second film is thermoformable.
21. A multilayer coextruded frangible film for cook-in applications comprising;
(a) a first layer, a second layer, a third layer, and a fourth layer;
(b) wherein said first layer comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer and blends thereof;
(c) wherein said second layer comprises a first blend component; said first blend component comprises a material selected from the group consisting of polypropylene, polybutene copolymer, and blends thereof and said first blend component is immiscible with a second blend component, said second blend component comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer, ethylene/vinyl acetate copolymer, polyethylene, anhydride-modified polyolefin, ionomer, anhydride-modified ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, anhydride-modified ethylene/α-olefin copolymer, and blends thereof; wherein said second layer is disposed between said first layer and said third layer;
(d) wherein said third layer comprises a material selected from the group consisting of polyethylene, anhydride-modified polyolefin, ethylene/vinyl alcohol copolymer, polyamide and blends thereof;
(e) wherein said fourth layer comprises a material selected from the group consisting of ethylene/vinyl alcohol copolymer, polyamide, polyethylene, anhydride-modified polyolefin and blends thereof; and
(f) wherein said second layer is adapted to peel from said first layer or said third layer under a force of between 1000-2500 g/in. (393.7-984.3 g/cm) as measured in accordance with the Standard Heat Seal Strength Test.
22. A multilayer coextruded frangible film according to claim 21 , wherein said first layer is free of polybutene copolymer and is a heat-sealable, outer-film layer.
23. A multilayer coextruded frangible film according to claim 21 , wherein said ethylene/α-olefin copolymer of said first layer has a melting point of less than 105° C. as measured in accordance with ASTM D-3418, a molecular weight distribution M w /M n of from 0.05-2.7 as measured in accordance with ASTM D-3593-80, and a melt index of from 5.0-34 g/10 min. at 190° C. as measured in accordance with ASTM D-1238 Condition 190° C./2.16 kg.
24. A multilayer coextruded frangible film according to claim 21 , wherein said film is thermoformable.
25. A multilayer coextruded frangible film according to claim 21 , wherein said anhydride-modified polyolefin comprises a maleic anhydride-grafted copolymer of between 0.05-1% by weight of maleic anhydride and between 99.95-99% by weight of polyolefin relative to the total weight of said anhydride-modified polyolefin.
26. A multilayer coextruded frangible film according to claim 21 , wherein said film has an unrestrained linear thermal shrinkage in the machine direction or the transverse direction of less than 5% at 100° C. as measured in accordance with ASTM D-2732 test method.
27. A multilayer coextruded frangible film according to claim 21 , wherein said film has an oxygen transmission rate of from about 0.01-1.00 cm 3 /100 in. 2 (0.1550-15.50 cm 3 /m 2 ) as measured in accordance with ASTM D-3985-81 test method.
28. A multilayer coextruded frangible film according to claim 21 , further comprising a fifth layer; wherein said fifth layer comprises a material selected from the group consisting of polyethylene, polybutene copolymer, anhydride-modified polyolefin, and blends thereof.
29. A multilayer coextruded frangible film according to claim 28 , wherein said film is thermoformable.
30. A multilayer coextruded frangible film according to claim 28 , further comprising a sixth layer; wherein said sixth layer comprises an ethylene/α-olefin copolymer.
31. A multilayer coextruded frangible film according to claim 30 , further comprising a seventh layer; wherein said seventh layer comprises an ethylene/α-olefin copolymer.
32. A multilayer coextruded frangible film according to claims 21 , 28 , 30 , or 31 ; wherein said film forms a package adapted for storing and cooking food items.
33. A multilayer coextruded frangible film according to claim 32 , wherein said first layer of said film is heat sealed to itself to form said package.
34. A multilayer coextruded frangible film according to claim 32 , wherein said first layer of said film is heat sealed to a second film to form said package.
35. A multilayer coextruded frangible film according to claim 34 , wherein said second film is thermoformable.
36. A multilayer coextruded frangible film for cook-in applications comprising;
(a) a first layer, a second layer, a third layer, a fourth layer, a fifth layer, a sixth layer, and a seventh layer;
(b) wherein said first layer comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer and blends thereof;
(c) wherein said second layer comprises a first blend component selected from the group consisting of polypropylene, polybutene copolymer, and blends thereof; said first blend component is immiscible with a second blend component; said second blend component comprises a material selected from the group consisting of ethylene/α-olefin copolymer, propylene/ethylene copolymer, ethylene/vinyl acetate copolymer, polyethylene, anhydride-modified polyolefin, ionomer, anhydride-modified ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, anhydride-modifled ethylene/α-olefln copolymer, and blends thereof; wherein said second layer is disposed between said first layer and said third layer;
(d) wherein said third layer comprises a material selected from the group consisting of polyethylene, anhydride-modifled polyolefin, ethylene/vinyl alcohol copolymer, polyamide and blends thereof;
(e) wherein said fourth layer comprises a material selected from the group consisting of ethylene/vinyl alcohol copolymer, polyamide, polyethylene, anhydride-modified polyolefin and blends thereof;
(f) wherein said fifth layer comprises a material selected from the group consisting of polyethylene, polybutene copolymer, anhydride-modified polyolefin, and blends thereof;
(g) wherein said sixth layer comprises an ethylene/α-olefln copolymer;
(h) wherein said seventh layer comprises an ethylene/α-olefln copolymer; and
(i) wherein said second layer is adapted to peel from said first layer or said third layer under a force of between 1000-2500 g/in. (393.7-984.3 g/cm) as measured in accordance with the Standard Heat Seal Strength Test.
37. A multilayer coextruded frangible film according to claim 36 , wherein said first layer is free of polybutene copolymer and is a heat-sealable, outer-film layer.
38. A multilayer coextruded frangible film according to claim 36 , wherein said ethylene/α-olefin copolymer of said first layer has a melting point of less than 105° C. as measured in accordance with ASTM D-3418, a molecular weight distribution M w /M n of from 0.05-2.7 as measured in accordance with ASTM D-3593-80, and a melt index of from 5.0-34 g/10 min. at 190° C. as measured in accordance with ASTM D-1238 Condition 190° C./2.16 kg.
39. A multilayer coextruded frangible film according to claim 36 , wherein said film is thermoformable.
40. A multilayer coextruded frangible film according to claim 36 , wherein said anhydride-modifled polyolefin comprises a maleic anhydride-grafted copolymer of between 0.05-1% by weight of maleic anhydride and between 99.95-99% by weight of polyolefin relative to the total weight of said anhydride-modified polyolefin.
41. A multilayer coextruded frangible film according to claim 36 , wherein said film has an unrestrained linear thermal shrinkage in the machine direction or the transverse direction of less than 5% at 100° C. as measured in accordance with ASTM D-2732 test method.
42. A multilayer coextruded frangible film according to claim 36 , wherein said film has an oxygen transmission rate of from about 0.01-1.00 cm 3 /100 in. 2 (0.1550-15.50 cm 3 /m 2 ) as measured in accordance with ASTM D-3985-81 test method.
43. A multilayer coextruded frangible film according to claim 36 ; wherein said film forms a package adapted for storing and cooking food items.
44. A multilayer coextruded frangible film according to claim 43 , wherein said first layer of said film is heat sealed to itself to form said package.
45. A multilayer coextruded frangible film according to claim 43 , wherein said first layer of said film is heat sealed to a second film to form said package.
46. A multilayer coextruded frangible film according to claim 45 , wherein said second film is thermoformable.
47. A multilayer coextruded frangible film according to claims 1 , 3 , 21 or 36 , wherein said second layer is adapted to peel from said first layer or said third layer under a force of between 1000-2500 g/in. (393.7-984.3 g/cm) as measured in accordance with the Standard Heat Seal Strength Test after said film is submerged in water at 100° C. for one hour.