초록

Multilayer thermoformable structures for packaging film applications. The multilayer structures having at least a first layer of polyester, a second layer of a first adhesive and a third layer of a nylon blend formed into a flexible non-oriented film by coextrusion.

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1. A multilayered structure comprising:a) a first layer of polyester, wherein said polyester is selected from the group consisting of a homopolymer or copolymer of ethylene terephthalate, ethylene naphthalate and blends thereof; b) a second layer of an adhesive; c) a third layer comprising a nylon o

1. A multilayered structure comprising:a) a first layer of polyester, wherein said polyester is selected from the group consisting of a homopolymer or copolymer of ethylene terephthalate, ethylene naphthalate and blends thereof; b) a second layer of an adhesive; c) a third layer comprising a nylon or nylon blend, wherein said third layer is a bend between about 100% (wt.) to about 71% (wt.) of a nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6.9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co- dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11(polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; and between about 0% (wt.) to about 29% (wt.) of an amorphous nylon; said first layer, said second layer and said third layer are formed into a flexible film by a coextrusion process such that said first layer, said second layer and said third layer have a combined thickness of 10 mils or less; and wherein said film is nonoriented and has a heat shrinkage value of less than about 5% in the machine direction at 90° C. and less than about 5% in the transverse direction at 90° C. 2. A multilayered structure according to claim 1, wherein said film is produced by slot cast or single-bubble blown coextrusion.3. A multilayered structure according to claim 1, wherein said first layer is an outer-surface layer of said film.4. A multilayered structure according to claim 1, wherein said second layer is directly adhered to said first layer.5. A multilayered structure according to claim 1, wherein said film has a thickness between about 3 mils to about 7 mils.6. A multilayered structure according to claim 1 wherein said film has a heat shrinkage value less than about 2% in the machine direction at 90° C. and less than about 2% in the transverse direction at 90° C.7. A multilayered structure according to claim 1, wherein said film contains less than 500 ppm of a transition-metal salt selected from the group consisting of manganese II, manganese III, iron II, iron III, cobalt II, cobalt m, nickel II, nickel III, copper I, copper II, rhodium II, rhodium III, rhodium IV, and ruthenium.8. A multilayered structure according to claim 1, wherein said film has a gloss value greater than about 65 Hunter Units (HU).9. A multilayered structure according to claim 1, wherein said film comprises processing additives.10. A multilayered structure according to claim 1, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, alklyl acrylates, vinyl esters, ethylene-alpha olefins and blends thereof.11. A multilayered structure according to claim 10, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof.12. A multilayered structure according to claim 1, wherein at least one additional layer is adhered to said film by thermal lamination, adhesive lamination, coextrusion coating or coextrusion lamination.13. A multilayered structure according to claim 1, further comprises a fourth layer of an oxygen barrier or an adhesive.14. A multilayered structure according to claim 13, wherein said oxygen barrier is selected from the group consisting of ethylene vinyl alcohol copolymer, polyvinylidene chloride, polyvinylidene chloride copolymers, polyacrylonitrile, acrylonitrile copolymers, and blends thereof.15. A multilayered structure according to claim 14, wherein said oxygen barrier has an oxygen transmission rate less than about 15.5 cc/m2 for 24 hours at 1 atmosphere.16. A multilayered structure according to claim 13, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer of copolymer of ethylene, alkyl acrylates, vinyl esters, ethylene-alpha olefins and blends thereof.17. A multilayered structure according to claim 16, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof.18. A multilayered structure according to claim 13, further comprising a filth layer comprising a nylon or nylon blend.19. A multilayered structure according to claim 18, wherein said fifth layer nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co-dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide- co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 polyauryllactam) and alloys or mixtures thereof.20. A multilayered structure according to claim 19, wherein said fifth layer is a blend between about 100% (wt.) to 71% (wt.) of a nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (polyhexamethyene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co- dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11(polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; and between about 0% (wt.) to about 29% (wt.) of an amorphous nylon.21. A multilayered structure according to claim 18, further comprising a sixth layer of an adhesive.22. A multilayered structure according to claim 21, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer of copolymer of ethylene, alkyl acrylates, vinyl esters, ethylene-alpha olefins and blends thereof.23. A multilayered structure according to claim 22, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylated, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof.24. A multilayered structure according to claim 21, further comprising a seventh layer of a sealant.25. A multilayered structure according to claim 24, wherein said sealant is selected from a group consisting of an ionomer, heterogeneous ethylene alpha olefin copolymer, a homogeneous ethylene alpha olefin copolymer, ethylene vinyl acetate copolymer, ethylene methyl acrylate copolymer, ethylene propylene copolymer, polybutylene homopolymer or copolymer, and blends thereof.26. A multilayered structure according to claim 1, wherein said first layer, said second layer and said third layer from a substrate of a larger multilayered-film being coextruded.27. A multilayered structure according to claim 1, wherein said film has a percent elongation at breatk at room temperature greater than about 250 in the machine direction and greater than about 250 in the transverse direction.28. A multilayered structure comprising:a) a first layer of polyester, wherein said polyester is selected from the group consisting of a homopolymer or copolymer of ethylene terephthalate, ethylene naphthalate and blends thereof; b) a second layer of an adhesive; c) a third layer comprising a nylon blend, wherein said third layer is a blend between about 100% (wt.) to about 71% (wt.) of a nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene (nonanediamide)), nylon 6, 10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co- dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; and between about 0% (wt.) to about 29% (wt.) of an amorphous nylon; said first layer, said second layer and said third layer are formed into a flexible film by a coextrusion process wherein said film has a heat shrinkage value less than about 5% in the machine direction direction at 90° C. less than about 5% in the transverse direction at 90° C.; and said film has a percent elongation at break at room temperature greater than about 250 in the machine direction and greater than about 250 in the transverse direction. 29. A multilayered structure comprising:a) a first layer selected from the group consisting of a homopolymer or corpolymer of ethylene terephthalate, ethylene naphthalate and blends thereof; b) a second layer of an adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, alkyl acrylates, vinly esters, ethylene-alpha olfefins and blends thereof; c) a third layer is a nylon selected from the group consisting nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonandeiamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6, 12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co-dodecanediamide)), nylon 6,6/6 (polyhexamethylene adipamide-co-caprolactam)),, nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; said first layer, said second layer and said third layer are formed into a flexibile film by a coextrusion process wherein said film is nonoriented; and wherein said film has a gloss value greater than about 65 Hunter Units (HU). 30. A multilayered structure according to claim 29, wherein said film is produced by slot cast or single-bubble blown coextrusion.31. A multilayered structure according to claim 29, wherein said first layer is an outer-surface layer of said film.32. A multilayered structure according to claim 29, wherein said second layer is directly adhered to said first layer.33. A multilayered structure according to claim 29, wherein said film has a thickness less than about 16 mils.34. A multilayered structure according to claim 33, wherein said film has a thickness less than about 10 mils.35. A multilayered structure according to claim 34, wherein said film has a thickness between about 3 mils to about 7 mils.36. A multilayered structure according to claim 29, wherein said film has a heat shrinkage value less than about 5% in the machine direction at 90° C. and less than about 5% in the transverse direction at 90° C.37. A multilayered structure according to claim 36, wherein said film has a heat shrinkage value less than about 2% in the machine direction at 90° C. and less than about 2% in the transverse direction at 90° C.38. A multilayered structure according to claim 29, wherein said film contains less than 500 ppm of a transition-metal salt selected from the group consisting of manganese II, manganese III, iron II, iron III, cobalt II, cobalt III, nickel II, nickel III, copper I, copper II, rhodium II, rhodium III, rhodium IV, and ruthenium.39. A multilayered structure according to claim 29, wherein said film comprises processing additives.40. A multilayered structure according to calim 29, wherein at least one additional layer is adhered to said film by thermal lamination, adhesive lamination, coextrusion coating, or coextrusion lamination.41. A multilayered structure according to claim 29, further comprises a fourth layer of an oxygen barrier or an adhesive.42. A multilayered structure according to claim 41, wherein said oxygen barrier is selected from the group consisting of ethylene vinyl alcohol copolymer.43. A multilayered structure according to claim 41, wherein said oxygen barrier has an oxygen trnasmission rate less than about 15.5 cc/m2 for 24 hours at 1 atmosphere.44. A multilayered structure according to claim 41, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer of copolymer of ethylene, alkyl acrylates, vinyl esters, ethylene-alpha olfefins and blends thereof.45. A multilayered structure according to claim 44, wherein adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof.46. A multilayered structure according to claim 29, further comprising a fifth layer comprising a nylon or nylon blend.47. A multilayered structure according to claim 46, wherein said fifth layer is a nylon selected from the group consisting of nylon 4, 6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sabacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co-dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof.48. A multilayered structure according to claim 47, wherein said fifth layer is a blend between about 100% (wt.) to abut 71% (wt.) of a nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co- dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; and between about 0% (wt.) of an amorphous nylon.49. A multilayered structure according to claim 41, further comprises a sixth layer of an adhesive.50. A multilayered structure according to claim 49, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer of copolymer of ethylene, alkyl acrylates, vinly esters, ethylene-alpha olefins and blends thereof.51. A multilayered structure according to claim 50, wherein adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylated, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolyers, ethylene-alpha olefins and blends thereof.52. A multilayered structure according to claim 49, further comprises a seventh layer of a sealant.53. A multilayered structure according to claim 52, wherein said sealant is selected from a group consisting of an ionomer, heterogeneous ethylene alpha olefin copolymer, a homogeneous ethylene alpha olefin copolymer, ethylene vinyl acetate copolymer, ethylene methyl acrylate copolymer, ethylene propylene copolymer, polybutylene homopolymer or copolymer, and blends thereof.54. A multilayered structure according to claim 29, wherein said first layer, and second layer and said third layer form a substructure of a larger multilayered-film being coextruded.55. A multilayered structure according to claim 29, wherein said film has a percent elongation at breat at room temperature greater than about 250 in the machine direction and greater than about 250 in the transverse direction.56. A multilayered structure comprising:a) a first layer selected from the group consisting of a homopolymer or copolymer of ethylene terephthalate, ethylene naphthalate and blends thereof; b) a second layer of an adhesive selected from the group consisting of modified or unmodified homopolymer or copolymer of ethylene, alkyl acrylates, vinyl esters, ethylene-alpha olefins and blends thereof; c) a third layer is a nylon selected from the group consisting of nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co-dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; said first layer, said second layer and said third layer are formed into a flexible film by a coextrusion process wherein said film has a heat shrinkage value less than about 5% in the machine direction 90° C. and less than about 5% in the transverse direction at 90° C.; and said film has a percent elongation at breat at room temperature greater than about 250 in the machine direction and greater than about 250 in the transverse direction. 57. A multilayered structure comprising:a) a first layer selected from the group consisting of homopolymer or copolymer of poly (ethylene terephthalate), poly (ethylene naphthalate) and blends thereof; b) a second layer of an adhesive selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof; c) a third layer of a blend between about 100 % (wt.) to abut 71 % (wt.) of a nylon selected from a group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co- dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11(polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; and between about 0 % (wt.) to about 29 % (wt.) of an amorphous nylon; and said first layer, said second layer and said third layer are formed into a flexible film by a coextrusion process wherein said film is nonoriented. 58. A multilayered structure according to claim 57, wherein said multilayered film is produced by slot cast or single-bubble blown coextrusion.59. A multilayered structure according to claim 57, wherein said first layer is an outer-surface layer of said film.60. A multilayered structure according to claim 57, wherein said second layer is directly adhered to said first layer.61. A multilayered structure according to claim 57, wherein said film has a thickness less than about 16 mils.62. A multilayered structure according to claim 61, whereinn said film has a thickness less than about 10 mils.63. A multilayered structure according to claim 62, wheren said film has a thickness between about 3 mils to 7 mils.64. A multilayered structure according to claim 57, wherein said film has a heat shrinkage values less than about 2% in the machine direction at 90° C. and less than 2% in the transverse direction at 90° C.65. A multilayered structure according to claim 64, wherein said film has a heat shrinkage value less than about 2% in the machine direction at 90° C. and less than about 2% in the transverse direction at 90° C.66. A multilayered structure according to claim 57, wherein said film contains less than 500 ppm of a transition-metal salt selected from the group consisting of manganese II, manganese III, iron II, iron III, cobalt II, cobalt III, nickel II, nickel III, copper I, copper II, rhodium II, rhodium III, rhodium IV, and ruthenium.67. A multilayered structure according to claim 57, wherein said film has a gloss value greater than about 65 Hunter Units (HU)._68. A multilayered structure according to claim 57, wherein said film comprises processing additives.69. A multilayered structure accordint to claim 57, wherein at least one additional layer is adhered to said film by thermal lamination, adhesive lamination, coextrusion coating, or coextrusion lamination.70. A multilayered structure according to claim 57, further comprises a fourth layer of an oxygen barrier or an adhesive.71. A multilayered structure according to claim 70, wherein said oxygen barrier is selected from the group consisting of ethylene vinyl alcohol polymer, polyvinylidene chloride, polyvinylidene chloride copolymers, polyacrylonitrile, acrylonitrile copolymers, and blends thereof.72. A multilayered structure according to claim 70, wherein said oxygen barrier has an oxygen transmission rate less than about 15.5 cc/m2 hours at 1 atmosphere.73. A multilayered structure according to claim 70, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer of copolymer of ethylene, alkyl acrylates, vinly esters, ethylene-alpha olefins and blends thereof.74. A multilayered structure according to claim 73, wherein adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof.75. A multilayered structure according to claim 70, further comprising a fifth layer comprising a nylon or nylon blend.76. A multilayered structure according to claim 75, wherein said fifth layer is nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co-dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof.77. A multilayered structure according to claim 76, wherein said fifth layer is a blend between about 100% (wt.) to abut 71% (wt.) of a nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylene dodecanediamide)), nylon 6/12 (poly(caprolactam-co- dodecanediamide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam) and alloys or mixtures thereof; and between about 0% (wt.) to about 29% (wt.) of an amorphous nylon.78. A multilayered structure according to claim 75, further comprises a sixth layer of an adhesive.79. A multilayered structure according to claim 78, wherein said adhesive is selected from the group consisting of a modified or unmodified homopolymer of copolymer of ethylene, alkyl acrylates, vinyl esters, ethylene-alpha olefins and blends thereof.80. A multilayered structure according to claim 79, wherein adhesive is selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olfefins and blends thereof.81. A multilayered structure according to claim 78, further comprises a seventh layer of a sealant.82. A multilayered structure according to claim 81, wherein said sealant is selected from a group consisting of an ionomer, heterogeneous ethylene alpha olfefin copolymer, a homogeneous ethylene alpha olefin copolymer, ethylene vinyl acetate copolymer ethylene methyl acrylate copolymer, ethylene propylene copolymer, polybutylene homopolymer or copolymer, and blends thereof.83. A multilayered structure according to claim 57, wherein said first layer, and second layer and said third layer form a substructure of a larger multilayered-film being coextruded.84. A multilayered structure according to claim 57, wherein said film has a percent elongation at breat at room temperature greater than about 250 in the machine direction and greater than about 250 in the transverse direction.85. A multilayered structure comprising:a) a first selected from the group consisting of homopolymer and copolymer of poly (ethylene terephthalate), poly (ethylene naphthalate) and blends thereof; b) a second layer of an adhesive selected from the group consisting of a modified or unmodified homopolymer or copolymer of ethylene, methyl acrylate, ethyl acrylate, n- butyl acrylate, ethylene vinyl acetate, ethylene vinyl acetate copolymers, ethylene-alpha olefins and blends thereof; c) a third layer of a blend between about 100% (wt.) to about 71(wt.) of a nylon selected from the group consisting of nylon 4,6 (poly(tetramethylene adipamide)), nylon 6 (polycaprolactam), nylon 6,6 (poly(hexamethylene adipamide)), nylon 6,9 (poly(hexamethylene nonanediamide)), nylon 6,10 (poly(hexamethylene sebacamide)), nylon 6,12 (poly(hexamethylen dodecanediamide)), nylon 6/12 (poly(caprlactam-co- dodecanedimaide)), nylon 6,6/6 (poly(hexamethylene adipamide-co-caprolactam)), nylon 11 (polyundecanolactam), nylon 12 (polyauryylactam) and alloys or mixtures thereof; and between about 0% (wt.) to about 29% (wt.) of an amorphous nylon; said first layer, said second layer and third layer are formed into a flexible film by a coextrusion process wherein said film has a heat shrinkage value less than about 5% in the machine direction at 90° C. and less than about 5% in the transverse direction at 9020 C.; and said film has a percent elongation at breat at room temperature greater than about 250 in the machine direction and greater than about 250 in the transverse direction.