Carbon dioxide gas permeable packaging film

Abstract

A carbon dioxide permeable packaging film providing moisture barrier, sealability, and flex-crack resistance characteristics and is ideal for use in packaging of carbon dioxide respiring food products, such as Swiss cheese, to increase shelf life thereof

1 . A packaging film comprising:
 a barrier layer having a first surface and a second surface opposite the first surface, said barrier layer comprising a coextruded multilayer structure having a moisture barrier core layer effective to limit passage of moisture through the packaging film;   an abuse layer disposed on the first surface of the barrier layer, said abuse layer effective to resist flex cracking of the packaging film and to control oxygen and carbon dioxide permeation; and   a sealant layer disposed on the second surface of the barrier layer, the sealant layer configured to provide a hermetic seal at high packing speed upon being heat sealed with a like sealant layer of an aligned packaging film.   
     
     
         2 . The packaging film of  claim 1 , wherein the barrier layer comprises:
 a first outer layer on a first side of the moisture barrier core layer and a second outer layer on a second side of the core layer opposite the first side of a middle barrier layer.   
     
     
         3 . The packaging film of  claim 2 , wherein the first and second outer layers are selected from a polyolefin and polyolefin copolymer. 
     
     
         4 . The packaging film of  claim 3 , wherein the first and second outer layers are selected from polyethylene or ethylene vinyl acetate. 
     
     
         5 . The packaging film of  claim 4 , wherein the first and second outer layers are formed of polyethylene having a density in the range of from 0.90 to 0.94 g/cm 3 . 
     
     
         6 . The packaging film of  claim 1 , wherein the barrier layer has a thickness of 0.8 mil to 2.0 mil. 
     
     
         7 . The packaging film of  claim 1 , wherein the moisture barrier core layer contains high density polyethylene (HDPE) having a density in the range of from 0.93 to 0.97 g/cm 3 . 
     
     
         8 . The packaging film of  claim 1 , wherein the abuse layer contains biaxially oriented nylon. 
     
     
         9 . The packaging film of  claim 1 , further comprising:
 an adhesive layer disposed between the abuse layer and the barrier layer.   
     
     
         10 . The packaging film of  claim 9 , wherein the adhesive layer is selected from polyethylene and polyurethane. 
     
     
         11 . The packaging film of  claim 1 , wherein the sealant layer is a low seal initiation temperature ethylene copolymer having a comonomer content of about 12% or higher and a melt flow index of about 20 g/in or higher. 
     
     
         12 . The packaging film of  claim 1 , wherein the sealant layer is an ethylene vinyl acetate (EVA). 
     
     
         13 . A method of manufacturing a moisture barrier packaging film comprising the steps of:
 coextruding a multilayer barrier structure having a first surface and a second surface opposite the first surface, said multilayer barrier layer comprising a moisture barrier core layer;   attaching an abuse layer to the first surface of the multilayer barrier structure; and   forming a sealant layer on the second surface.   
     
     
         14 . The method of  claim 13 , wherein the abuse layer is attached to the first surface using an adhesive. 
     
     
         15 . The method of  claim 13 , wherein sealant layer is formed on the second surface using an extrusion coating process. 
     
     
         16 . The method of  claim 13 , wherein the multilayer barrier structure includes:
 a first outer layer on a first side of the moisture barrier core layer and a second outer layer on a second side of the core layer opposite the first side of a middle barrier layer.   
     
     
         18 . The method of  claim 16 , wherein each of the first and second outer layers is selected from the group consisting of polyethylene and polyethylene copolymers. 
     
     
         18 . The method of  claim 13 , wherein the moisture barrier core layer contains high density polyethylene (HDPE). 
     
     
         19 . The method of  claim 13 , wherein the abuse layer contains biaxially oriented nylon. 
     
     
         20 . The method of  claim 12 , wherein the sealant layer is a low seal initiation temperature ethylene copolymer. 
     
     
         21 . A food package, comprising:
 opposing front and back panels of a polymer packaging film;   a barrier layer of the polymer packaging film having a first surface and a second surface opposite the first surface, said barrier layer comprising a coextruded multilayer structure having a moisture barrier core layer effective to limit passage of moisture through the packaging film;   an abuse layer of the packaging film disposed on the first surface of the barrier layer, said abuse layer effective to resist flex cracking of the packaging film and to control oxygen and carbon dioxide permeation;   a sealant layer of the packaging film disposed on the second surface of the barrier layer, the sealant layer configured to provide a hermetic seal upon being heat sealed with a like sealant layer of an aligned packaging film; and   a hermetic seal between at least a portion of the front and back panels of the polymer packaging film.