Barrier lidding structure based on polypropylene film

Abstract

Multi-layer films suitable as sealable or peelable sheet that can be used for closing foodstuff containers are described. These multi-layer films includes a polymeric substrate layer and a seal or a peel-seal layer. The multilayer composite film preferably includes four component layers, namely in order, a polymeric base layer for mechanical strength, a thin organic barrier layer, an ethylene polymer-based adhesive layer, and a heat seal layer including an ethylene copolymer, such as ethylene vinyl acetate copolymer. The film is useful as a peelable heat sealable lid for containers of diverse polymer compositions storing various products such as foodstuffs and pharmaceuticals.

1 . A container comprising:
 a container body comprising a lid sealant surface; and   a lid comprising a multilayer film comprising:
 a polymeric base layer; 
 an organic harrier layer with a thickness of less than 1.5 microns of a surface of the base layer; 
 an adhesion layer comprising an oxidized polyethylene; and 
 a heat seal layer comprising a thermoplastically adhesive ethylene polymer. 
   
     
     
         2 . The container of  claim 1 , wherein the lid sealant surface comprises crystallized polyethylene terephthalate (CPET), amorphous polyethylene terephthalate (APET), foil, polyethylene terephthalate-coated paperboard, PVC, glass, or aliphatic olefin polymers. 
     
     
         3 . The container of  claim 2 , wherein the barrier layer is formed from a blend comprising ethylene vinyl alcohol and polyvinyl alcohol. 
     
     
         4 . The container of  claim 3 , wherein the barrier layer further comprises crosslinking and defoaming agents. 
     
     
         5 . The container of  claim 2 , wherein the base layer has a thickness of 5-75 microns. 
     
     
         6 . The container of  claim 2 , wherein the base layer is mono or biaxially oriented. 
     
     
         7 . The container of  claim 2 , wherein the adhesive layer has a thickness of 1-50 microns. 
     
     
         8 . The container of  claim 2 , wherein the heat seal layer comprises an ethylene vinylacetate copolymer. 
     
     
         9 . The container of  claim 8 , wherein the heat seal layer further comprises polyethylene. 
     
     
         10 . The container of  claim 2 , wherein the heat seal layer has a thickness of 10-75 microns. 
     
     
         11 . The container of  claim 2 , wherein the film has an oxygen transmission rate (OTR) determined according to ASTM D-3985 of 1 cc/100 in 2 /day or less, tested at 65% relative humidity at 20° C. 
     
     
         12 . The container of  claim 2 , wherein the film as a moisture transmission rate determined according to ASTM F-1249 of less than 0.2 gm/100 in 2 /day or less, at 90% relative humidity at 100° C.