Method for forming a container with corrugated wall and rolled lip

Abstract

A method of forming a paper container uses a three-ply corrugated material having at an outer sheet of paper that may be stretched circumferentially to permit subsequent rolling of the corrugated material about a mandrel and an inner sheet of paper that can be stretched circumferentially to assist in rolling the lip of the cup and/or attaching the bottom to the cup. An extensible paper having two axes of extension of over four percent can be used for one or both of the paper layers.

1 . A method of manufacturing a paper container comprising the steps of: 
 (a) premanufacturing a substantially planar corrugated paperboard with an outside paper layer providing at least four percent extensibility along a machine direction of the paper layer, an inside paper layer providing at least four percent extensibility along a machine direction of the paper layer, each outside paper layer glued respectively face toward face, with aligned machine directions, on either side of a middle corrugated paper layer having flutes extending along a vertical direction to laminate the center corrugated paper layer between the first outside paper layer and the second outside paper layer;    (b) cutting a blank from the premanufactured corrugated paperboard;    (c) curving the cut blank of corrugated paperboard along a circumferential direction crossing the vertical direction and generally aligned with the machine directions of the outside and inside paper layers so that the outside paper layer is on the outside of the curve; and    (d) attaching a bottom wall to a lower curved edge of the curved and cut corrugated paperboard blank; and    (e) rolling an upper curved edge outward into a lip on the cut and curved corrugated paperboard blank.    
   
   
       2 . The method of  claim 1  wherein the outside layer is creped paper.  
   
   
       3 . The method of  claim 1  wherein the inside layer is extensible Kraft paper.  
   
   
       4 . The method of  claim 1  wherein the middle corrugated paper layer provides greater than four percent extensibility along a machine direction of the middle corrugated paper layer as aligned with the machine directions of the outside paper layer and inside paper layer.  
   
   
       5 . The method of  claim 4  wherein the middle corrugated paper layer is extensible Kraft paper.  
   
   
       6 . The method of  claim 5  wherein the middle corrugated paper layer also provides at least four percent extensibility along a cross direction.  
   
   
       7 . The method of  claim 1  the inside paper layer further provides at least four percent extensibility along a cross direction of the inside paper layer perpendicular to the machine direction.  
   
   
       8 . The method of  claim 1  the inside paper layer further providing at least five percent extensibility along the machine direction.  
   
   
       9 . The method of  claim 1  including the step of: 
 crushing the upper curved edge of the corrugated paper board so that the corrugated paper layer is flattened before rolling the upper curved edge into a lip.    
   
   
       10 . A paper container comprising: 
 an outside paper layer of creped paper, the creped paper oriented to provide extension circumferentially around the container;    an inside paper layer of extensible Kraft, the extensible Kraft having a machine direction oriented circumferentially around the container;    a middle corrugated paper layer having flutes extending from end to end of the container as laminated between the outside paper layer and the inside paper layer to form a container wall;    a bottom attached to a lower edge of the container wall; and    a lip rolled outward in an upper edge of the container wall.    
   
   
       11 . The container of  claim 10  wherein the container wall is frusto-conical.  
   
   
       12 . The container of  claim 10  wherein the outside paper layer is creped paper.  
   
   
       13 . The container of  claim 10  wherein the inside paper layer is extensible Kraft paper.  
   
   
       14 . The container of  claim 10  wherein the middle corrugated paper layer provides greater than four percent extensibility along a machine direction of the middle corrugated paper layer as aligned with the machine directions of the outside paper layer and inside paper layer.  
   
   
       15 . The container of  claim 14  wherein the middle corrugated paper layer is extensible Kraft paper.  
   
   
       16 . The container of  claim 14  wherein the middle corrugated paper layer also provides at least four percent extensibility along a cross direction.  
   
   
       17 . The container of  claim 10  the inside paper layer further provides at least four percent extensibility along a cross direction of the inside paper layer perpendicular to the machine direction  
   
   
       18 . The container of  claim 10  the inside paper layer further providing at least six percent extensibility along the machine direction.  
   
   
       19 . The container of  claim 10  including the step of: 
 crushing the upper curved edge of the corrugated paper board so that the corrugated paper layer is flattened before rolling the upper curved edge into a lip.