초록 ▼

Novel films, and processes for making them, are provided. The films are characterized by the inclusion of a layer of vinylidene chloride copolymer between at least two other layers which contain ethylene vinyl acetate, and optionally linear low density polyethylene. The films may be unoriented or

Novel films, and processes for making them, are provided. The films are characterized by the inclusion of a layer of vinylidene chloride copolymer between at least two other layers which contain ethylene vinyl acetate, and optionally linear low density polyethylene. The films may be unoriented or oriented. Oriented films may optionally be cross-linked. The novel process of making the cross-linked films includes the step of cross-linking the film after assembly of the vinylidene chloride copolymer layer into the structure.

대표청구항 ▼

The invention claimed is: 1. A multiple layer polymeric film comprising first and second layers, the compositions of said first and second layers includes ethylene vinyl acetate copolymer wherein the composition of at least one of said first and second layers is a blend of 10% by weight to 90% by w

The invention claimed is: 1. A multiple layer polymeric film comprising first and second layers, the compositions of said first and second layers includes ethylene vinyl acetate copolymer wherein the composition of at least one of said first and second layers is a blend of 10% by weight to 90% by weight linear low density polyethylene and 90% to 10% ethylene vinyl acetate; and a third layer of vinylidene chloride-methylacrylate copolymer disposed between said first and second layers. 2. A multiple layer film as in claim 1 wherein the compositions of said first and second layers are both 20% to 40% linear low density polyethylene and 80% to 60% ethylene vinyl acetate, said ethylene vinyl acetate having a vinyl acetate content of 7% to 12% and a melt index of 0.2 to 0.8; said linear low density polyethylene having a melt index of 0.5 to 1.5. 3. A package made fom a film of claim 2. 4. A package made fom a film of claim 1. 5. A molecularly oriented multiple layer polymeric film having first and second layers whose composition includes ethylene vinyl acetate copolymer wherein the composition of at least one of said first and second layers is a blend of 10% by weight to 90% by weight linear low density polyethylene and 90% to 10% ethylene vinyl acetate, and a third layer of vinylidene chloride-methylacrylate copolymer disposed between said first and second layers; each of said first, second and third layer having been molecularly oriented. 6. A package made fom an oriented film of claim 5. 7. A molecularly oriented multiple layer polymeric film comprising first and second layers whose composition includes ethylene vinyl acetate copolymer wherein the composition of at least one of said first and second layers is a blend of 10% by weight to 90% by weight linear low density polyethylene and 90% to 10% ethylene vinyl acetate; and a third layer whose composition is made from a vinylidene chloride copolymer, said third layer being disposed between said first and second layers; each of said first, second, and third layers having been cross-linked by a crosslinking stimulus in an amount equivalent to exposure to at least 1.5 megarads of electron beam irradiation wherein each of the first, second and third layers are exposed to the same amount of the crosslinking stimulus. 8. A molecularly oriented multiple layer film as in claim 7 wherein the composition of said third layer is vinylidene chloride-methylacylate copolymer. 9. A molecularly oriented multiple layer film as in claim 8 wherein the compositions of said first and second layers are both 20% to 40% linear low density polyethylene and 80% to 60% ethylene vinyl acetate, said ethylene vinyl acetate having a vinyl acetate content of 6% to 12% and a melt index, before cross-linking, of 0.2 to 0.8; said linear low density polyethylene having a melt index, before cross-linking, of 0.5 to 1.5. 10. A package made from an oriented film of claim 8. 11. A package made from an oriented film of claim 7. 12. An oriented multiple layer polymeric film, comprising: (a) first and second layers, each of said first and second layers having two surfaces, said first and second layers both having essentially the same composition, each as the other, and said first and second layers collectively comprising a first pair of layers; (b) a third layer of vinylidene chloride-methylacrylate copolymer between, and in surface contact with said first and second layers; and (c) fourth and fifth layers adhered to said first and second layers on the respective surfaces opposite said third layer, said fourth and fifth layers having essentially the same composition, each as the other, and said fourth and fifth layers collectively comprising a second pair of layers; wherein at least one or both of said first and second pairs of layers comprises: (i) at least 50% ethylene vinyl acetate and the remainder linear low density polyethylene, or, (ii) at least 10% linear low density polyethylene and the remainder ethylene vinyl acetate; or (iii) at least 10% linear low density polyethylene and at least 50% ethylene vinyl acetate. 13. An oriented film as in claim 12 wherein said first pair of layers comprises 70% to 100% of said ethylene vinyl acetate and said second pair of layers comprises 10% to 90% linear low density polyethylene. 14. An oriented film as in claim 13 wherein said first pair of layers comprises 100% ethylene vinyl acetate and said second pair of layers comprises 50% to 90% linear low density polyethylene. 15. An oriented film as in claim 14 wherein each of said layers has been cross-linked in an amount equivalent to exposure to at least 1.5 megarads of electron beam irradiation. 16. A package made from an oriented film of claim 15. 17. A package made from an oriented film of claim 14. 18. An oriented film as in claim 13 wherein each of said layers has been cross-linked in an amount equivalent to exposure to at least 1.5 megarads of electron beam irradiation. 19. A package made from an oriented film of claim 18. 20. A package made from an oriented film of claim 13. 21. An oriented film as in claim 12 wherein said first pair of layers comprises 50% to 100% linear low density polyethylene and said second pair of layers comprises 50% to 100% of said ethylene vinyl acetate. 22. An oriented film as in claim 21 wherein said first pair of layers comprises 90% to 100% linear low density polyethylene and said second pair of layers comprises 90% to 100% ethylene vinyl acetate. 23. An oriented film as in claim 22 wherein each of said layers has been cross-linked in an amount equivalent to exposure to at least 1.5 megarads of electron beam irradiation. 24. A package made from an oriented film of claim 23. 25. An oriented film as in claim 21 wherein each of said layers has been cross-linked in an amount equivalent to exposure to at least 1.5 megarads of electron beam irradiation. 26. A package made from an oriented film of claim 25. 27. A package made from an oriented film of claim 21. 28. An oriented film as in claim 12 wherein each of said layers has been cross-linked in an amount equivalent to at least 1.5 megarads of electron beam irradiation. 29. A package made from an oriented film of claim 28. 30. A package made from an oriented film of claim 12. 31. An oriented multiple layer polymeric film, comprising: (a) first and second layers, each of said first and second layers both having essentially the same composition, each as the other, and said first and second layer collectively comprising a first pair of layers; (a) a third barrier layer of vinylidene chloride-methylacrylate copolymer between, and in surface-to-surface contact with, said first and second layers; and (c) fourth and fifth layers adhered to said first and second layers on the respective surfaces opposite said third layer, said fourth and fifth layers having essentially the same composition, each as the other, and said fourth and fifth layers collectively comprising a second pair of layers; wherein each of said layers is cross-linked by a cross-linking stimulus in an amount equivalent to exposure to at least 1.5 megarads of electron beam irradiation wherein each of the layers is exposed to the same amount of the stimulus, and, at least one or both of said first and second pairs of layers comprises: (i) at least 50% ethylene vinyl acetate and the remainder linear low density polyethylene, or, (ii) at least 10% linear low density polyethylene and the remainder ethylene vinyl acetate; or (iii) at least 10% linear low density polyethylene and at least 50% ethylene vinyl acetate. 32. An oriented film as in claim 31 wherein said first pair of layers comprises 70% to 100% of said ethylene vinyl acetate and said second pair of layers comprises 10% to 90% linear low density polyethylene. 33. An oriented film as in claim 32 wherein said first pair of layers comprises 100% ethylene vinyl acetate and said second pair of layers comprises 50% to 90% linear low density polyethylene. 34. An oriented film as in claim 31 wherein said first pair of layers comprises 50% to 100% linear low density polyethylene and said second pair of layers comprises 50% to 100% of said ethylene vinyl acetate. 35. An oriented film as in claim 34 wherein said first pair of layers comprises 90% to 100% linear low density polyethylene and said second pair of layers comprises 90% to 100% ethylene vinyl acetate. 36. A package made from an oriented film of claim 31.