Claims
- 1. A method of improving the adhesion between a layer of vinylidene chloride copolymer and a layer of a linear ethylene/alpha-olefin copolymer comprising the steps of:
- (a) blending an ethylene/butyl-acrylate copolymer with a linear ethylene/alpha-olefin copolymer, wherein said linear ethylene/alpha-olefin copolymer has a 4 carbon or higher comonomer;
- (b) forming a film layer from said blend; and
- (c) melt joining the layer of said blended copolymers directly to a layer of vinylidene chloride copolymer.
- 2. The method of claim 1 wherein the step of melt joining the layers is performed by coextruding the two layers.
- 3. The method of claim 1 wherein the step of melt joining the two layers is performed by extrusion coating one layer onto the other.
- 4. The method of claim 1 wherein the step of blending includes blending about 5% to 40% by weight of ethylene/butyl-acrylate copolymer with 95% to 60% by weight of the linear ethylene/alpha-olefin copolymer.
- 5. The method of claim 1 where the ethylene/alpha-olefin copolymer has a density of less than about 0.920 gms/cc.
- 6. The method of claim 1 wherein the ethylene/alpha-olefin copolymer has a density in the range of about 0.905 to about 0.915 gms/cc, the butyl acrylate content of the ethylene/butyl-acrylate copolymer is in the range from about 2% to about 6%, and the blending step includes blending about 10% to about 25% by weight of ethylene/butyl-acrylate copolymer with about 90% to about 75% by weight of the linear ethylene/alpha-olefin copolymer.
- 7. The method of claim 2 including the step of extrusion coating the two coextruded layers onto a thermoplastic substrate.
- 8. The method of claim 7 including the further step of stretching the substrate and layers coextruded thereonto.
- 9. In making a multi-layer, heat shrinkable packaging film having a layer comprising a vinylidene chloride copolymer and a layer adjacent thereto comprising a linear ethylene/alpha-olefin copolymer wherein said linear ethylene/alpha-olefin copolymer has a 4 carbon or higher comonomer, the improvement which comprises blending at least about 5% by weight of ethylene/butyl-acrylate copolymer in the mixture comprising the linear copolymer layer thereby improving the adhesion between said two layers.
- 10. In the process of making a heat shrinkable bag constructed from multi-layer thermoplastic film having a barrier layer of vinylidene chloride copolymer and an adjacent layer comprising a linear ethylene/alpha-olefin copolymer wherein said linear ethylene/alpha-olefin copolymer has a 4 carbon or higher comonomer, the improvement which comprises blending at least about 5% by weight of ethylene/butyl-acrylate copolymer in the linear copolymer mixture comprising the adjacent layer thereby improving the adhesion between the adjacent and barrier layers.
- 11. The process of claim 10 including the steps of selecting a linear copolymer for the adjacent layer having density of less than 0.920 gms/cc and blending 10% to 25% by weight ethylene/butyl-acrylate copolymer having 2% to 6% by weight butyl-acrylate content in 90% to 75% by weight of the linear copolymer.
Parent Case Info
This is a divisional application of application Ser. No. 880,258, filed on June 30, 1986, now U.S. Pat. No. 4,755,436.
US Referenced Citations (19)
Divisions (1)
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Number |
Date |
Country |
Parent |
880258 |
Jun 1986 |
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