Packaging material

Abstract

A packaging laminate includes a core layer (or web) with through-holes covered on one side with a first outer layer, and on another side with a second outer layer, such that the first and second outer layers are sealed to each other within the through-holes. To provide a permanent seal between the outer layers, the web can be flame-treated to activate or polarize parts of the first outer layer within the through-holes.

1 . A packaging laminate, comprising: 
 a core layer of paper or paperboard including through-holes;    a first outer layer of thermoplastic on a first side of the core layer and covering the through-holes;    a second outer layer covering the through-holes on a second side of the core layer, the second outer layer comprising aluminum foil and a layer of thermoplastic;    pull or opening strips on an outer surface of the first outer layer, the pull or opening strips releasably seal the first outer layer and second outer layer to each other within a region of an opening contour of the respective through-holes; and    a sealing- or lamination layer between the first outer layer and second outer layer, the sealing- or lamination layer releasably seals the first outer layer and second outer layer to each other within the region of the opening contour of the respective through-holes.    
   
   
       2 . The packaging laminate as claimed in  claim 1 , wherein the aluminum foil faces towards and is in contact with (i) the sealing- or lamination layer and (ii) the layer of thermoplastic of the second outer layer.  
   
   
       3 . The packaging laminate as claimed in  claim 1 , wherein the sealing- or lamination layer is extruded in an ozone atmosphere to produce bonding sites in the surface of the sealing- or lamination layer, the bonding sites provide enhanced sealing strength between (i) the sealing- or lamination layer and the second side of the core layer and (ii) the sealing-or lamination layer and the aluminum foil; and 
 a surface of the aluminum foil facing away from the sealing- or lamination layer is activated or polarized prior to contact with the thermoplastic layer of the second outer layer which is permanently sealed to the surface of the aluminum foil by activated or polarized bonding sites of the aluminum foil.    
   
   
       5 . The packaging laminate as claimed in  claim 1 , wherein the first outer layer and the layer of thermoplastic of the second outer layer are of low density polyethylene.  
   
   
       6 . The packaging laminate as claimed in  claim 1 , wherein the pull or opening strips are (i) sealed to the first outer layer in a rupturable sealing joint around the opening contour of the respective through-holes and (ii) sealed permanently to the first outer layer within the respective through-holes.  
   
   
       7 . The packaging laminate as claimed in  claim 1 , which consists essentially of: 
 the core layer;    the first outer layer;    the second outer layer;    the pull or opening strips; and    the sealing- or lamination layer.    
   
   
       8 . A packaging container comprising a packaging laminate as claimed in  claim 1 .  
   
   
       9 . A packaging laminate, comprising: 
 a core layer including through-holes;    a first outer layer on a first side of the core layer and covering the through-holes;    a second outer layer covering the through-holes on a second side of the core layer, the second outer layer including aluminum foil facing towards the core layer and an outermost layer applied on a surface of the aluminum foil facing away from the core layer, the aluminum foil and the outermost layer are disposed within the respective through-holes, the first and second outer layers are sealed to each other within the respective through-holes; and    the first side of the web and parts of the second outer layer are activated or polarized within the respective through-holes prior to applying the first outer layer on the first side of the core layer to provide enhanced adhesion of the first outer layer to the first side of the core layer.    
   
   
       10 . The packaging laminate as claimed in  claim 9 , wherein the first outer layer and second outer layer are sealed to each other by an as-extruded sealing- or lamination layer applied on the second side of the core layer between the first outer layer and second outer layer.  
   
   
       11 . The packaging laminate as claimed in  claim 9 , wherein the sealing- or lamination layer is extruded in an ozone atmosphere to produce bonding sites in the surface of the sealing- or lamination layer, the bonding sites provide enhanced sealing strength between (i) the sealing- or lamination layer and the second side of the core layer and (ii) the sealing-or lamination layer and the aluminum foil; and 
 a surface of the aluminum foil facing away from the sealing- or lamination layer is activated or polarized prior to contact with the thermoplastic layer of the second outer layer which is permanently sealed to the as-treated surface of the aluminum foil by activated or polarized bonding sites of the aluminum foil.    
   
   
       12 . The packaging laminate as claimed in  claim 9 , wherein: 
 the core layer consists of paper or paperboard; and    the first outer layer and the outermost layer of the second layer are of thermoplastic.    
   
   
       13 . A packaging container comprising a packaging laminate as claimed in  claim 9 .  
   
   
       14 . A packaging laminate produced by a method comprising: 
 covering through-holes on a first side of a web with a first outer layer of a thermoplastic; and    then covering the through-holes on a second side of the web with a second outer layer comprising aluminum foil and a layer of thermoplastic such that the first outer layer and second outer layer are sealed to each other within the regions of the opening contours of the through-holes by a sealing- or lamination layer extruded between the first outer layer and second outer layer.    
   
   
       15 . A packaging laminate as claimed in  claim 14 , wherein pull or opening strips are (i) sealed to the first outer layer in a rupturable sealing joint around the opening contour of the respective through-holes and (ii) sealed permanently to the first outer layer within the respective through-holes.  
   
   
       16 . A packaging container comprising a packaging laminate as claimed in  claim 14 .  
   
   
       17 . A packaging laminate produced by a method comprising: 
 providing a web of a core layer with through-holes, the web having a first side and a second side;    coating the second side of the web with a second outer layer including an aluminum foil facing towards the web and an outermost layer applied on the surface of the aluminum foil facing away from the web; and    thereafter coating the first side of the web with a first outer layer such that the first and second outer layers are sealed to each other within the regions of the opening contour of the respective through-holes and the aluminum foil and the outermost layer are disposed within the regions of the through-holes;    wherein the web with the through-holes, after coating with the second outer layer but prior to coating with the first outer layer, is subjected to flame-treating during which the first side of the web and accessible parts of the second outer layer are, to promote adhesion, activated or polarized within the regions of the through-holes.    
   
   
       18 . A packaging laminate as claimed in  claim 17 , wherein pull or opening strips are (i) sealed to the first outer layer in a rupturable sealing joint around the opening contour of the respective through-holes and (ii) sealed permanently to the first outer layer within the respective through-holes.  
   
   
       19 . A packaging container comprising a packaging laminate as claimed in  claim 17 .  
   
   
       20 . A packaging laminate, comprising: 
 a core layer including through-holes;    a first outer layer of thermoplastic coated on a first side of the core layer and covering the through-holes;    a sealing- or lamination layer coated on a second side of the core layer and covering the through-holes;    aluminum foil on a side of the sealing- or lamination layer facing away from the core layer and covering the through holes;    a second outer layer coated on the aluminum foil and covering the through-holes; and    pull or opening strips on an outer surface of the first outer layer and covering the through holes.    
   
   
       21 . A packaging container comprising a packaging laminate as claimed in  claim 20.