Method for extending the effective life of an oxygen scavenger in a container wall

Abstract

A method of filling a container, and thereby extending the effective life of an oxygen scavenger, includes providing a container having an oxygen scavenger material, introducing product contents and a liquefied gas into the container to displace at least a portion of the air within the headspace, and capping or otherwise sealing the container. Displacing oxygen from the headspace diminishes the available oxygen within the container that can permeate into the container sidewall, thereby extending the effective life of the scavenger.

We claim:  
     
         1 . A method for extending effective life of an oxygen scavenger that is disposed in the wall of a container, comprising the steps of: 
 a. providing the container formed of a material comprising the oxygen scavenger;    b. introducing a comestible product into the container, thereby forming a headspace between a product fill line a rim of the container;    c. introducing a quantity of liquefied gas into the container;    d. enabling vaporized liquefied gas to displace at least a portion of air in the headspace; and    e. capping the container so as to maintain low oxygen partial pressure within the headspace relative to ambient atmospheric pressure, thereby diminishing the amount of oxygen available to permeate from inside the container into the oxygen scavenger.    
     
     
         2 . The method of  claim 1  wherein the container wall includes an outer layer of PET, an interior layer of an oxygen scavenging compound comprising nylon, and an inner layer of PET for contacting the product.  
     
     
         3 . The method of  claim 1  wherein the container wall includes a single layer comprising a blend of an oxidizable polymer and a non-oxidizable polymer.  
     
     
         4 . The method of  claim 1  wherein the container wall includes a blend of an oxygen scavenger material and polyethylene terephthalate.  
     
     
         5 . The method of  claim 1  wherein the oxygen scavenger is an oxidizable organic component and a metal catalyst.  
     
     
         6 . The method of  claim 5  wherein the organic component is a polymer.  
     
     
         7 . The method of  claim 5  wherein the organic component is a polyamide.  
     
     
         8 . The method of  claim 5  wherein the organic component a condensation polymer of m-xylylenediamine and adipic acid.  
     
     
         9 . The method of  claim 1  wherein the liquefied gas forms a positive total pressure inside the container after the capping step (e).  
     
     
         10 . The method of  claim 9  wherein the introducing step (b) includes introducing the comestible product into the container at an elevated temperature.  
     
     
         11 . The method of  claim 10  wherein the oxygen partial pressure within the headspace is below about 3.1 psi.  
     
     
         12 . The method of  claim 1  wherein the oxygen partial pressure within the headspace is below about 2.75 psi upon capping.  
     
     
         13 . The method of  claim 1  wherein the oxygen partial pressure within the headspace is below about 2.3 psi upon capping.  
     
     
         14 . The method of  claim 1  wherein the oxygen partial pressure within the headspace is below about 1.54 psi upon capping.  
     
     
         15 . The method of  claim 1  wherein the oxygen partial pressure within the headspace is below about 0.77 psi upon capping.  
     
     
         16 . The method of  claim 1  wherein capping step (e) thereby forms an oxygen partial pressure gradient across the container wall.  
     
     
         17 . The method of  claim 1  wherein the quantity of liquefied gas is sufficient to maintain a positive total pressure within the container upon cooling to ambient temperature.  
     
     
         18 . The method of  claim 1  wherein the quantity of liquefied gas is sufficient to maintain a positive total pressure within the container upon cooling to approximately 50 degrees F.  
     
     
         19 . The method of  claim 1  wherein the quantity of liquefied gas is sufficient to maintain a positive total pressure within the container upon cooling to approximately 40 degrees F.  
     
     
         20 . The method of  claim 1  wherein the quantity of liquefied gas is such that the container has a substantially atmospheric pressure upon cooling to ambient temperature.  
     
     
         21 . The method of  claim 1  wherein the liquefied gas comprises liquefied nitrogen.  
     
     
         22 . The method of  claim 1  wherein the liquefied gas is an inert gas.  
     
     
         23 . The method of  claim 1  wherein the liquefied gas is liquefied nitrogen.