Plastic composite barrier structures

Abstract

Composite moisture and oxygen barrier structures in the form of films, sheets, tubes and bottles are described which are composed of foils of high density polyethylene and foils of polar oxygen barrier resins adhered to each other with a coextruded bonding resin composition composed of blends of predominantly high density polyethylene containing low levels of a grafted unsaturated dicarboxylic acid anhydride and linear low density polyethylenes which are copolymers of ethylene with either octene-1 or butene-1. The preferred dicarboxylic acid anhydride is maleic anhydride. The oxygen barrier resins are preferably ethylene/vinyl alcohol copolymers or amorphous polycarboxylamides from condensation polymerization of aliphatic diamines and aromatic dicarboxylic acids.

I claim: 
     
       1. A coextruded composite packaging film comprising at least one foil of a high density linear polyethylene adhered to at least one foil of a polar, oxygen barrier resin with a melt extrudable bonding resin composition, said oxygen barrier resin foil being selected from the group consisting of ethylene/vinyl alcohol copolymer, polyvinyl alcohol and polycarboxylamides, said melt extrudable bonding resin composition consisting essentially of a blend of from 70 to 90 weight percent of composition (i) and from 10 to 30 weight percent of composition (ii) wherein composition (i) is composed of a blend of high density linear polyethylene having a melt index in the range of from 0.1 to 8.0 g/10 min. and a density in the range of from above 0.950 to 0.970 g/cm 3  and sufficient of a modified linear high density polyethylene having a density in the range of 0.950 to 0.970 g/cm 3  and a melt index in the range of from 0.1 to 8.0 g/10 min. having from .[.0.7 to 14 mole.]. .Iadd.0.5 to 1 weight .Iaddend.percent of unsaturated dicarboxylic acid anhydride grafted to a portion of said high density linear polyethylene to provide from .[.0.245 to 1.05 mole.]. .Iadd.0.055 to 0.2 weight .Iaddend.percent of said grafted anhydride in said composition (i), and wherein composition (ii) is a linear low density polyethylene selected from the group consisting of linear copolymers of ethylene with butene-1 and linear copolymers of ethylene with octene-1 having a density in the range of 0.912 to 0.930 g/cm 3  and a melt index in the range of 0.5 to 6.0 g/10 min. 
     
     
       2. A composite packaging film of claim 1 in which the melt extrudable bonding resin is composed of 80 to 90 weight percent of composition (i) and 10 to 20 weight percent of composition (ii). 
     
     
       3. A composite packaging film of claim 2 in which the linear high density polyethylene employed in composition (i) has a melt index in the range of 0.8 to 2.5 g/10 min and a density in the range of 0.955 to 0.960 g/cm 3  and in which the linear low density polyethylene of composition (ii) has a density in the range of 0.917 to 0.920 g/cm 3  and a melt index in the range of 1.0 to 2.5 g/10 min. 
     
     
       4. A composite packaging film of claim 1 in which the foil of oxygen barrier resin is composed of an amorphous polycarboxylamide which is the condensation polymerization product of hexamethylenediamine and a mixture of terephthalic and isophthalic acids. 
     
     
       5. A composite packaging film of claim 1 in which the foil of oxygen barrier resin is composed of ethylene/vinyl alcohol copolymer. 
     
     
       6. A composite packaging film of claim 1 composed of from two to four foils of high density linear polyethylene having a polar, oxygen barrier foil disposed between each high density linear polyethylene foil and adhered on both sides of each polar oxygen barrier foil to the adjacent high density linear polyethylene foil with said melt-extrudable bonding resin composition. 
     
     
       7. A composite packaging film of claim 6 in which the foils of oxygen barrier resin are composed of an amorphous polycarboxylamide which is the condensation polymerization product of hexamethylenediamine and a mixture of terephthalic and isophthalic acids. 
     
     
       8. A composite packaging film of claim 6 in which the foils of oxygen barrier resin are composed of ethylene/vinyl alcohol copolymer. 
     
     
       9. A composite packaging film of claim 1 in which the foil of oxygen barrier resin is composed of an ethylene/vinyl alcohol copolymer and which contains, in addition, between said ethylene/vinyl alcohol copolymer foil and an outer foil of linear high density polyethylene, a foil extruded from a reground composite packaging film of the composition of claim 1 adhered to the foil of ethylene/vinyl alcohol copolymer with said bonding resin composition. 
     
     
       10. A composite packaging film of claim 1 in which the foil of oxygen barrier resin is composed of an ethylene/vinyl alcohol copolymer and which contains, in addition, between said ethylene/vinyl alcohol copolymer foil and an outer foil of linear high density polyethylene a foil of ethylene/vinyl acetate copolymer adhered to the foil of ethylene/vinyl alcohol copolymer with said bonding resin composition. 
     
     
       11. A composite packaging film of claim 1 in which the foil of oxygen barrier resin is composed of an ethylene/vinyl alcohol copolymer and which contains, in addition, between said ethylene/vinyl alcohol copolymer foil and an outer foil of linear high density polyethylene, an additional foil of an ethylene/vinyl acetate copolymer adhered to the foil of ethylene/vinyl alcohol copolymer with said bonding resin composition. 
     
     
       12. A coextruded blown plastic bottle having one wall composed of high density linear polyethylene adhered to the other wall composed of an amorphous polycarboxylamide with a melt-extrudable bonding resin composition consisting essentially of a blend of from 80 to 90 weight percent of composition (i) and from 10 to 20 weight percent of composition (ii) wherein composition (i) is composed of a blend of high density linear polyethylene having a melt index in the range of from 0.8 to 6.0 and a density in the range of from 0.955 to 0.960 g/cm 3  and sufficient of said high density linear polyethylene having from .[.0.7 to 14 mole.]. .Iadd.0.5 to 1 weight .Iaddend.percent of an unsaturated dicarboxylic acid anhydride grafted to a portion of said high density linear polyethylene to provide from .[.0.245 to 1.05 mole.]. .Iadd.0.055 to 0.2 weight .Iaddend.percent of said grafted anhydride in said composition (i), and wherein composition (ii) is a linear low density polyethylene selected from the group consisting of linear copolymers of ethylene with butene-1 and linear copolymers of ethylene with octene-1 having a density in the range of 0.917 to 0.920 and a melt index in the range of 1.0 to 2.5 g/10 min. 
     
     
       13. A blown plastic bottle of claim 11 in which the unsaturated dicarboxylic acid anhydride is maleic anhydride. 
     
     
       14. A blown bottle of claim 12 in which the amorphous polycarboxylamide wall is composed of the condensation product of hexamethylenediamine and a mixture of terephthalic and isophthalic acids.