Stress relieving indent formation for very thin thermoformed plastic films or foil/plastic laminates

Abstract

A pouch-style package formed of thin film comprising a front wall, a back wall, edge seals joining the front wall and back wall, and at least one bulge formation formed in a wall of the pouch-style package, having a stress-relieving indent formed in the wall in which said bulge formation is formed, the stress-relieving indent providing material to relieve excessive thinning or stress cracking at corners of the bulge formation.

1 . A pouch-style package formed of thin film and containing a product to be dispensed, the pouch-style package formed by a process comprising the steps of: 
 providing a first thin film comprising laminated layers of metal foil and plastic;    providing a second thin film comprising laminated layers of metal foil and plastic;    forming a stress-relieving indent in at least the first thin film by air pressure forming;    sealing the first thin film to the second thin film at edge seals, the edge seals defining edges of the pouch-style package, wherein the pouch-style package comprises a first wall formed of the first thin film and a second wall formed of the second thin film, and wherein the first wall comprises the stress-relieving indent; and    forming a bulge formation in said first wall, wherein the step of forming a bulge formation includes the step of having the stress-relieving indent flatten or deform to facilitate the formation of the bulge formation in said first wall.    
   
   
       2 . A pouch-style package as claimed in  claim 1 , wherein said bulge formation has corners and wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking at corners of the bulge formation.  
   
   
       3 . A pouch-style package as claimed in  claim 2 , wherein the corners of the bulge formation are rounded ball corners.  
   
   
       4 . A pouch-style package as claimed in  claim 1 , wherein the indent is a reverse indent so as to form a stress-relieving protrusion.  
   
   
       5 . A pouch-style package as claimed in  claim 1 , wherein the indent is a relatively shallow flat indent with semi-circular ends.  
   
   
       6 . A pouch-style package as claimed in  claim 1 , wherein the indent has a semi-circular cross-section.  
   
   
       7 . A pouch-style package as claimed in  claim 1 , wherein the indent is oblong in shape.  
   
   
       8 . A pouch-style package as claimed in  claim 1 , wherein the step of forming a bulge formation in said first wall takes place prior to sealing the first thin film to the second thin film.  
   
   
       9 . A pouch-style package as claimed in  claim 1 , wherein the step of forming a bulge formation in said first wall takes place after sealing the first thin film to the second thin film.  
   
   
       10 . A pouch-style package as claimed in  claim 1 , wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking in the bulge formation.  
   
   
       11 . A process for forming a pouch-style package comprising the steps of: 
 providing a first thin film comprising laminated layers of metal foil and plastic;    providing a second thin film comprising laminated layers of metal foil and plastic;    forming a stress-relieving indent in at least the first thin film by air pressure forming;    sealing the first thin film to the second thin film at edge seals, the edge seals defining edges of the pouch-style package, wherein the pouch-style package comprises a first wall formed of the first thin film and a second wall formed of the second thin film, and wherein the first wall comprises the stress-relieving indent; and    forming a bulge formation in said first wall, wherein the step of forming a bulge formation includes the step of having the stress-relieving indent flatten or deform to facilitate the formation of the bulge formation in said first wall.    
   
   
       12 . A process for forming a pouch-style package as claimed in  claim 11 , wherein said bulge formation has corners and wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking at corners of the bulge formation.  
   
   
       13 . A process for forming a pouch-style package as claimed in  claim 12 , wherein the corners of the bulge formation are rounded ball corners.  
   
   
       14 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the indent is a reverse indent so as to form a stress-relieving protrusion.  
   
   
       15 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the indent is a relatively shallow flat indent with semi-circular ends.  
   
   
       16 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the indent has a semi-circular cross-section.  
   
   
       17 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the indent is oblong in shape.  
   
   
       18 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the step of forming a bulge formation in said first wall takes place prior to sealing the first thin film to the second thin film.  
   
   
       19 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the step of forming a bulge formation in said first wall takes place after sealing the first thin film to the second thin film.  
   
   
       20 . A process for forming a pouch-style package as claimed in  claim 11 , wherein the stress-relieving indent provides material to relieve excessive thinning or stress cracking in the bulge formation.