Claims
- 1. A heat shrinkable film having improved shrink characteristics comprising ethylene vinyl acetate copolymer with nine to twenty percent by weight vinyl acetate, with narrow molecular weight distribution defined by a polydispersity ratio (Mz/Mn) of 5 to 10 wherein the number average molecular weight (Mn) is between about 150,000 and 30,000.
- 2. The film of claim 1 wherein the film is cross-linked.
- 3. The film of claim 2 wherein the film is electron beam cross-linked.
- 4. The film of claim 1 wherein the film has been formed by coextrusion.
- 5. The film of claim 1 wherein the film is in the form of a seamless tube.
- 6. A bag formed from tubular film according to claim 1 wherein the bottom of the bag is formed by a transverse seal across the flattened tube and the mouth is formed by severing the tube at a predetermined distance from said transverse seal.
- 7. The bag of claim 6, heat-shrunk about a contained food product.
- 8. A multilayer heat shrinkable film comprising:a) a first layer comprising a material selected from the group consisting of an acid copolymer, an ethylene alpha olefin copolymer, and blends thereof; and b) a second layer comprising ethylene vinyl acetate copolymer with nine to twenty percent by weight vinyl acetate, with narrow molecular weight distribution defined by a polydispersity ratio (Mz/Mn) of 5 to 10 wherein the number average molecular weight (Mn) is between about 15,000 and 30,000.
- 9. The film of claim 8 wherein at least one layer is cross-linked.
- 10. The film of claim 9 wherein at least one layer is electron beam cross-linked.
- 11. The film of claim 8 wherein the first and second layers have been formed by coextrusion.
- 12. The film of claim 8 wherein the film is in the form of a seamless tube with the first layer being the face of the inner tube wall.
- 13. The film of claim 8 wherein the ethylene alpha olef in copolymer has a density of less than about 0.915 g/cc.
- 14. The film of claim 8 wherein said acid copolymer of the first layer is ethylene-methacrylic acid, ethylene-acrylic acid, or a blend thereof.
- 15. A bag formed from tubular film according to claim 12 wherein the bottom of the bag is formed by a transverse seal across the flattened tube and the mouth is formed by severing the tube at a predetermined distance from said transverse seal.
- 16. The bag of claim 15, heat-shrunk about a contained food product.
- 17. A multilayer heat shrinkable film comprising:a) a first layer comprising a material selected from the group consisting of an acid copolymer, an ethylene alpha olefin copolymer, and blends thereof, b) a second layer comprising ethylene vinyl acetate copolymer with nine to twenty percent by weight vinyl acetate, with narrow molecular weight distribution defined by a polydispersity ratio (Mz/Mn) of 5 to 10 wherein the number average molecular weight (Mn) is between about 15,000 and 30,000; c) a third layer comprising a barrier copolymer, d) a fourth layer comprising ethylene vinyl acetate copolymer with nine to twenty percent by weight vinyl acetate, with narrow molecular weight distribution defined by a polydispersity ratio (Mz/Mn) of 5 to 10 wherein the number average molecular weight (Mn) is between about 15,000 and 30,000; and e) a fifth layer comprising an ethylene alpha olefin copolymer.
- 18. The film of claim 17 wherein at least one layer is cross-linked.
- 19. The film of claim 18 wherein at least one layer is electron beam cross-linked.
- 20. The film of claim 17 wherein the third, fourth and fifth layers are extrusion coated onto a substrate tape, and the substrate includes the first and second layers.
- 21. The film of claim 17 wherein all the layers have been formed by coextrusion.
- 22. The film of claim 17 wherein the film is in the form of a seamless tube with the first layer being the face of the inner tube wall.
- 23. The film of claim 17 wherein the ethylene alpha olefin copolymer has a density of less than about 0.915 g/cc.
- 24. The film of claim 17 wherein said acid copolymer of the first layer is ethylene-methacrylic acid, ethylene-acrylic acid, or blends thereof.
- 25. A bag formed from tubular film according to claim 22 wherein the bottom of the bag is formed by a transverse seal across the flattened tube and the mouth is formed by severing the tube at a predetermined distance from said transverse seal.
- 26. The bag of claim 25, heat-shrunk about a contained food product.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a Continuation-In-Part of U.S. patent application Ser. No. 07,907,725, filed Jul. 2, 1992, now abandoned.
US Referenced Citations (13)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0217252 |
Apr 1987 |
EP |
0447988 |
Sep 1991 |
EP |
WO 8707880 |
Dec 1987 |
WO |
Non-Patent Literature Citations (5)
Entry |
US Introducing Very Low . . . Plastics Technology Sep. 1984-p. 113.* |
US BP Chemicals Outlines . . . EP Plastics News Dec. 1984-p. 4.* |
US Ultralow Density PE's . . . Plastics World Oct. 1984-p. 86.* |
US New Kind of Polyethylene. Plastics Technology Oct. 1984-pp. 13/15.* |
US Stamylex PE DSM Feb. 1984. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
07/907725 |
Jul 1992 |
US |
Child |
08/078479 |
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US |