Packaging with a Vent Region

Abstract

Packaging comprises polymer film ( 1 ) with portions of the film ( 1 ) sealed together to form an enclosure for the food stuff, said sealed portions being sealed by a film-to-film seal except in a vent region ( 5 ) where a lacquer layer ( 6 ) is bonded to each portion of film before said portions are sealed together with the lacquer layers cohering, the seal strength of the lacquer-to-lacquer interface ( 6 ) being similar to that of the film-to-film interface under predetermined storage conditions, and the seal strength of said lacquer-to-lacquer interface ( 6 ) being reduced compared with that of the film-to-film interface at temperatures above those expected under said predetermined storage conditions so that the enclosure is vented to atmosphere by a cohesive peel action in the vent region ( 5 ) between said lacquer layers ( 6 ).

1 . Packaging for food stuff intended to be heated comprising polymer film with portions of the film sealed together to form an enclosure for the food stuff, said sealed portions being sealed by a film-to-film seal except in a vent region where a lacquer layer is bonded to each portion of film before said portions are sealed together with the lacquer layers cohering, the seal strength of the lacquer-to-lacquer interface being similar to that of the film-to-film interface under predetermined storage conditions, and the seal strength of said lacquer-to-lacquer interface being reduced compared with that of the film-to-film interface at temperatures above those expected under said predetermined storage conditions so that the enclosure is vented to atmosphere by a cohesive peel action in the vent region between said lacquer layers. 
   
   
       2 . Packaging as claimed in  claim 1  in which said enclosure is formed by sealing portions of the film together along multiple seams with a vent region formed in one or more seam. 
   
   
       3 . Packaging as claimed in  claim 2  in which said enclosure is formed by sealing portions of the film together along multiple seams with said vent region formed along the whole of one seam, but not along the whole of the length of all seam. 
   
   
       4 . Packaging as claimed in  claim 1  in which the lacquer is applied to the film by a gravure or flexo printing process. 
   
   
       5 . Packaging as claimed in  claim 1  in which the film comprises polypropylene, polyethylene, polyester, polyamide, regenerated cellulose, polylactic acid, or combination of any of the preceding. 
   
   
       6 . Packaging as claimed in  claim 5  in which the lacquer comprises an EVA based resin. 
   
   
       7 . Packaging as claimed in  claim 6  in which the lacquer comprises a combination of solvents comprising alcohols, esters and hydrocarbons. 
   
   
       8 . Packaging as claimed in  claim 1  in which the lacquer comprises a water-based EVA lacquer or an epoxy/acrylic solvent based lacquer. 
   
   
       9 . Packaging as claimed in  claim 1  in which the film is formed with microperforations to support a modified atmosphere within the packaging when it contains respiring food stuff. 
   
   
       10 . Film for the production of packaging of  claim 1  in which at least one region of the film adapted to be incorporated in a packaging seal between two portions of the film is coated with a lacquer comprising an EVA based resin.