Peel-off packaging system for fresh foodstuffs

Abstract

A sealing product to be sealed on at least one ring-shaped sealing zone which surrounds the opening of a container, made from a sealing sheet including a support layer of a fibrous material of mainly vegetable fibers and a multi-layer structure including, on one of its faces, an adhesive layer and, on its other face, a sealing layer, whereby the sealing product is stamped to make a relief whose form is such that its base follows, at least discontinuously, a contour close to that of the internal edge of the ring-shaped sealing zone, the structure of the sealing sheet including additionally an intermediate layer made of plastic having a good strength, able to undergo plastic deformation, and of which the average thickness is such as it endows the entire sealing product with sufficient malleability and resistance for it to be possible to stamp it to the desired shape without tearing.

1 . Sealing product ( 20 ), designed to be sealed on at least one ring-shaped sealing zone ( 4 ) which surrounds the opening ( 2 ) of a container ( 1 ), made from a sealing sheet comprising:
 a) a support layer ( 11 );   b) a typically co-extruded multi-layer structure ( 16 ), comprising,   i. on one of its faces, an adhesive layer ( 12 ) including an adhesive material chosen so as to adhere to said support layer,   ii. an intermediate layer ( 13 ) made of plastic, and,   iii. on its other face, a sealing layer ( 15 ) including a sealing material chosen so as to adhere, after heat sealing, to the ring-shaped sealing zone;   
       characterized in that:
 c) said support layer is a fibrous material mainly comprising vegetable fibers; 
 d) said intermediate layer ( 13 ) is made of a plastic with good strength, able to undergo plastic deformation, the average thickness of which is such that it endows the entire sealing product with sufficient malleability and resistance for it to be possible to stamp it without tearing so as to make a relief ( 24 ) whose form is such that its base ( 21 ) follows, at least discontinuously, a contour close to that of the internal edge ( 41 ) of said ring-shaped sealing zone. 
 
     
     
         2 . Sealing product according to  claim 1 , characterized in that said intermediate layer is made of plastic having a strength greater than 60 MPa, preferably greater than 80 MPa. 
     
     
         3 . Sealing product according to  claim 1 , characterized in that said intermediate layer is made of plastic having an elongation at rupture greater than 5%, preferably greater than 10%. 
     
     
         4 . Sealing product according to  claim 1 , characterized in that said intermediate layer is made of a plastic belonging to the group containing polyamides and thermoplastic polyesters. 
     
     
         5 . Sealing product according to  claim 4  in which said intermediate layer is made of polyamide 6 (PA6). 
     
     
         6 . Sealing product according to  claim 4  in which said intermediate layer is of polyethylene terephthalate (PET) not bi-axially oriented. 
     
     
         7 . Sealing product according to  claim 6  in which said polyethylene terephthalate (PET) has been suddenly cooled in order to give an amorphous or slightly crystallized structure. 
     
     
         8 . Sealing product according to  claim 1 , characterized in that the average thickness of said intermediate layer is greater than a tenth, and preferably greater than a fifth of the average thickness of said support layer when said average thicknesses are expressed in terms of surface density. 
     
     
         9 . Sealing product according to  claim 1 , in which said support layer has an elongation at rupture of at least 5%, whatever the test direction. 
     
     
         10 . Sealing product according to  claim 1 , in which said support layer ( 11 ) has an average thickness which, expressed in terms of surface density, ranges between 40 and 10 g/m 2 , and preferably close to 70 g/m 2 . 
     
     
         11 . Sealing product according to  claim 1 , in which said intermediate layer ( 13 ) has an average thickness ranging between 3 and 20 g/m 2 , and preferably in the vicinity of 15 g/m 2  for a support layer having an average thickness close to 70 g/m 2 . 
     
     
         12 . Sealing product according to  claim 1 , in which said sealing layer ( 15 ) has an average thickness which, expressed in terms of surface density, ranges between 3 and 20 g/m 2 , and preferably in the vicinity of 10 g/m 2 . 
     
     
         13 . Sealing product according to  claim 1 , in which the base ( 21 ) of the relief ( 24 ) is toroid in shape with a fillet radius typically greater than 5 times the total thickness of the sealing sheet. 
     
     
         14 . Sealing product according to  claim 1 , in which the tilted wall ( 23 ) of relief ( 24 ) is tilted by less than 45° in relation to the plane of the sealing sheet. 
     
     
         15 . Sealing product according to  claim 1 , characterized in that it also comprises a gripping tab ( 26 ).