Polymeric and film structure for use in shrink bags

Abstract

Linear low density polyethylene is used in multiple layer, molecularly oriented films. Novel blends of linear low density polyethylene with ethylene vinyl acetate copolymer are disclosed, and used in molecularly oriented multiple layer films. Bags made from the multiple layer films are especially useful for shrink packaging, and particularly for shrink packaging of meats having large cavities.

Having thus described the invention, what is claimed is: 
     
       1. An oriented multiple layer polymeric film, comprising: (a) a first .Iadd.gas .Iaddend.barrier layer, said first layer having two opposing surfaces;   (b) second and third layers adhered to said surfaces of said first layer, said second and third layers both having essentially the same composition;   (c) a fourth layer adhered to one of said second and third layers; and   (d) a fifth layer adhered to said fourth layer;   said second, third and fifth layers comprising ethylene vinyl acetate, and said fourth layer comprising 10% to 100% linear low density polyethylene.   
     
     
       2. An oriented film as in claim 1 wherein said .Iadd.gas .Iaddend.barrier layer comprises polyvinyl chloride-polyvinylidene chloride copolymer. 
     
     
       3. An oriented film as in claim 1 wherein said .Iadd.gas .Iaddend.barrier layer comprises ethylene vinyl alcohol copolymer. 
     
     
       4. An oriented multiple layer polymeric film, comprising: (a) a first .Iadd.gas .Iaddend.barrier layer, said first layer having two opposing surfaces;   (b) a second layer adhered to one said surface, said second layer being 10% to 90% linear low density polyethylene and 90% to 10% ethylene vinyl acetate; and   (c) a third layer adhered to the other said surface, the composition of said third layer being selected from the group consisting of (i) ethylene vinyl acetate, and (ii) blends of 10% to 90% linear low density polyethylene with 90% to 10% ethylene vinyl acetate.   
     
     
       5. An oriented film as in claim 4 wherein said .Iadd.gas .Iaddend.barrier layer comprises polyvinyl chloride-polyvinylidene chloride copolymer. 
     
     
       6. An oriented film as in claim 4 wherein said .Iadd.gas .Iaddend.barrier layer comprises ethylene vinyl alcohol copolymer. 
     
     
       7. An oriented film as in claim 5 or 6 wherein said third layer is a blend of 10% to 90% linear low density polyethylene and 90% to 10% ethylene vinyl acetate. 
     
     
       8. An oriented film as in claim 7 wherein said second and third layers are 20% to 40% linear low density polyethylene and 60% to 80% ethylene vinyl acetate, said ethylene vinyl acetate having a vinyl acetate content of 6% to 12% and a melt index of 0.3 to 0.9; said linear low density polyethylene having a melt index of 0.5 to 1.5. 
     
     
       9. An oriented multiple layer polymeric film comprising: (a) a first .Iadd.gas .Iaddend.barrier layer, said first layer having two opposing surfaces;   (b) second and third layers adhered to said surfaces of said first layer, said second and third layers both having essentially the same composition and comprising a first pair of layers; and   (c) fourth and fifth layers adhered to said second and third layers on the respective surfaces opposite said first layer, said fourth and fifth layers having essentially the same composition and comprising a second pair of layers;   in the combined composition of said first and second pairs of layers, at least one of said pairs comprising at least 50% of an ethylene vinyl acetate component, the remainder of said one pair being a linear low density polyethylene; and at least one of said pairs comprising at least 10% linear low density polyethylene component, the remainder of said one pair being said ethylene vinyl acetate, where the requirement for said components of at least 50% ethylene vinyl acetate and said 10% linear low density polyethylene may be met by one of said pairs having both said components or by each of said pairs having one of said components.   
     
     
       10. An oriented film as in claim 9 wherein said .Iadd.gas .Iaddend.barrier layer comprises polyvinyl chloride-polyvinylidene chloride copolymer. 
     
     
       11. An oriented film as in claim 9 wherein said .Iadd.gas .Iaddend.barrier layer comprises ethylene vinyl alcohol copolymer. 
     
     
       12. An oriented film as in claim 9, 10, or 11 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. 
     
     
       13. An oriented film as in claim 12 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. 
     
     
       14. An oriented film as in claim 9, 10, or 11 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. 
     
     
       15. An oriented film as in claim 14 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. 
     
     
       16. An oriented film as in claim 1, 2 or 3 wherein said fourth layer is 100% linear low density polyethylene. 
     
     
       17. An oriented film as in claim 4, 5, 6, 9, 10, 11, 12, or 3 wherein the overall composition of said film comprises 20% to 30% linear low density polyethylene. 
     
     
       18. An oriented film as in claim 7 wherein the overall composition of said film comprises 20% to 30% linear low density polyethylene. 
     
     
       19. An oriented film as in claim 8 wherein the overall composition of said film comprises 20% to 30% linear low density polyethylene. 
     
     
       20. An oriented film as in claim 13 wherein the overall composition of said film comprises 20% to 30% linear low density polyethylene. 
     
     
       21. An oriented film as in claim 15 wherein the overall composition of said film comprises 20% to 30% linear low density polyethylene. 
     
     
       22. A shrink bag made from an oriented film of claim 17. 
     
     
       23. A shrink bag made from an oriented film of claim 18. 
     
     
       24. A shrink bag made from an oriented film of claim 19. 
     
     
       25. A shrink bag made from an oriented film of claim 20. 
     
     
       26. A shrink bag made from an oriented film of claim 21. .Iadd. 
     
     
       27.  A multi-layer oriented film comprising a gas barrier layer and at least one layer comprising a blend of linear low density polyethylene and ethylene vinyl acetate. .Iaddend..Iadd.28. The invention of claim 27 wherein the blend comprises 10% to 90% linear low density polyethylene and 90% to 10% ethylene vinyl acetate. .Iaddend..Iadd.29. The invention of 
     
     
        claim 28 wherein the film is formed into a bag. .Iaddend..Iadd.30.  A multiple layer polymeric film comprising: (a) a first gas barrier layer, said first layer having first and second surfaces;   (b) one or more layers on one side of said first surface wherein at least one of said layers comprises (i) ethylene vinyl acetate or (ii) a blend of linear low density polyethylene and ethylene vinyl acetate or (iii) thermoplastic material;   (c) one or more layers on one side of said second surface wherein at least one of said layers comprises a blend of linear low density polyethylene and ethylene vinyl acetate. .Iaddend..Iadd.31. An invention of claim 30 wherein one or more of the blends comprises 10% to 90% linear low density   
     
     
        polyethylene and 90% to 10% ethylene vinyl acetate. .Iaddend..Iadd.32.  A heat shrinkable multi-layered film comprising a gas barrier layer and at least one layer comprising a blend of linear low density polyethylene and 
     
     
        ethylene vinyl acetate. .Iaddend..Iadd.33.  The invention of claim 32 wherein the film is formed into a bag. .Iaddend.