Tri-fold plastic bag roll, method and apparatus for making same

Abstract

A plastic bag is formed from a continuous extruded tube of polyethylene material. The tube is flattened and sealed across its width a intervals to form bag bottoms. The bags are joined to one another at a perforation line and folded in thirds lengthwise prior to being rolled into a compact roll, either with or without supporting core. After folding the bags may be chisel cut through the center of the perforation line to assist in dispensing of the bags. The chisel cut will extend through all layers of the bag when folded, resulting in three chisel cuts in the bag. The bags may be gusseted for part or as much as all of their width. The bags may also be corona treated and printed on their outer surfaces. The bags may be formed from partially recycled materials and various combinations of linear low density, medium and high density polyethylene.

1 . A tri-fold plastic bag roll, comprising: 
 a continuous web of plastic bags formed from polyethylene material, each of said bags comprising: 
 a front wall, said front wall having an inner surface, an outer surface, first and second side edges, a top edge and a bottom edge;  
 a rear wall, said rear wall having an inner surface, an outer surface, first and second side edges, a top edge and a bottom edge;  
 said front wall being joined to said rear wall at respective first and second side edges thereof;  
 said front wall being sealed to said rear wall adjacent respective bottom edges thereof;  
 an open mouth disposed at said top edges;  
   said front and rear walls of each of said bags being removably attached by a perforation line at said bottom edges to said top edges of a subsequent bag in said web;    said web being folded twice parallel to a long axis of said bags to form a compact bag web approximately one third of a width of said bags; and    said folded web being rolled to form a compact bag roll.    
   
   
       2 . The tri-fold plastic bag roll, as described in  claim 1 , further comprising: 
 a chisel cut, said chisel cut extending through a center point of said perforation line of said folded web; and    whereby, when said compact roll is installed in a bag dispenser said chisel cut will engage a separating tongue when bags are pulled from said roll, and when said bags are opened to said width, three chisel cuts will appear at said perforation line.    
   
   
       3 . The tri-fold plastic bag roll, as described in  claim 1 , wherein said compact web is rolled about a core.  
   
   
       4 . The tri-fold plastic bag roll, as described in  claim 1 , further comprising at least one side gusset, said side gusset extending inwardly from either of said first and second side edges of said front and rear walls.  
   
   
       5 . The tri-fold plastic bag roll, as described in  claim 4 , wherein said side gusset extends inwardly from either of said first and second side edges of said front and rear walls for up to one third of said width of said bags.  
   
   
       6 . The tri-fold plastic bag roll, as described in  claim 4 , wherein said side gusset extends inwardly from either of said first and second side edges of said front and rear walls for up to one half of said width of said bags.  
   
   
       7 . The tri-fold plastic bag roll, as described in  claim 1 , wherein said outer surface of at least one of said front wall and said rear wall of said bags is corona treated.  
   
   
       8 . The tri-fold plastic bag roll, as described in  claim 7 , wherein said corona treatment of said outer surface of at least one of said front and rear walls of each of said bags is an amount sufficient to result in a surface tension on said wall of at least about 38 dynes/cm.  
   
   
       9 . The tri-fold plastic bag roll, as described in  claim 7 , wherein said outer surface of at least one of said front wall and said rear wall of said bags is printed.  
   
   
       10 . The tri-fold plastic bag roll, as described in  claim 1 , wherein said first side edges are folded over said second side edges.  
   
   
       11 . The tri-fold plastic bag roll, as described in  claim 1 , wherein said first side edges are folded under said second side edges.  
   
   
       12 . The tri-fold plastic bag roll, as described in  claim 1 , wherein said polyethylene material is formulated from about 40-48 wt. % high density, high molecular weight polyethylene, 12-20 wt. % high density, medium molecular weight polyethylene, 20-30 wt. % linear low density polyethylene, 0-8 wt. % color concentrate.  
   
   
       13 . The tri-fold plastic bag roll, as described in  claim 1 , wherein said polyethylene material is formulated from about 10-20 wt. % recycled material, the recycled material comprising about 40-48 wt. % high density, high molecular weight polyethylene, 12-20 wt. % high density, medium molecular weight polyethylene, 20-30 wt. % linear low density polyethylene, 0-8 wt. % color concentrate.  
   
   
       14 . The tri-fold plastic bag roll, as described in  claim 12 , wherein 10-15 wt. % of said linear low density polyethylene has a density ranging from 0.923-0.924 gm/cc.  
   
   
       15 . The tri-fold plastic bag roll, as described in  claim 12 , wherein 10-15 wt. % of said linear low density polyethylene has a melt index ranging from 0.25-0.30 gm/10 minutes.  
   
   
       16 . The tri-fold plastic bag roll, as described in  claim 12 , wherein said high density, medium molecular weight polyethylene has a density ranging from 0.937-0.947 gm/cc.  
   
   
       17 . The tri-fold plastic bag roll, as described in  claim 12 , wherein said high density, medium molecular weight polyethylene has a melt index ranging from 0.10-0.30 gm/10 minutes.  
   
   
       18 . A method of making a tri-fold plastic bag roll, comprising the following steps: 
 extruding a tube of polyethylene material;    flattening said tube to form a continuous web, said web having upper and lower surfaces and first and second side edges;    sealing said tube perpendicular to said first and second side edges at predetermined intervals to form bag bottoms;    folding said web in thirds parallel to said first and second side edges to form a compact web;    perforating said compact web perpendicular to said first and second side edges to form a perforation line; and    rolling said compact web into a compact bag roll.    
   
   
       19 . The method of making a tri-fold plastic bag roll, as described in  claim 18 , comprising the further step of chisel cutting said compact web at a center point of said perforation line prior to rolling said compact web into a compact bag roll.  
   
   
       20 . The method of making a tri-fold plastic bag roll, as described in  claim 18 , comprising the further step of providing a bag roll core prior to rolling said compact web into a compact bag roll.  
   
   
       21 . The method of making a tri-fold plastic bag roll, as described in  claim 18 , comprising the further step of gusseting said tube of polyethylene material prior to flattening said tube to form a continuous web.  
   
   
       22 . The method of making a tri-fold plastic bag roll, as described in  claim 18 , comprising the further step of corona treating at least one of said upper and lower surfaces of said continuous web prior to sealing said tube perpendicular to said first and second side edges.  
   
   
       23 . The method of making a tri-fold plastic bag roll, as described in  claim 17 , comprising the further step of printing either of said upper and lower surfaces of said continuous web after corona treatment.  
   
   
       24 . An apparatus for making a tri-fold bag roll, comprising: 
 a supply of polyethylene material;    an extruder, said extruder capable of forming a continuous tube of thin film polyethylene;    a tubing flattener, said flattener capable of flattening said continuous tube into a continuous bag web;    a sealer, said sealer capable of forming a series of seals in said bag web perpendicular to a long axis of said web;    a folder, said folder capable of folding said bag web approximately in thirds parallel to said long axis to form a compact bag web;    a perforator, said perforator capable of perforating said compact bag web through six film layers and forming a perforation line; and    a bag roller, said bag roller capable of rolling said perforated compact bag web into a compact roll.    
   
   
       25 . The apparatus for making a tri-fold bag roll, as described in  claim 24 , further comprising a chisel cutter, said chisel cutter capable of forming a chisel cut through said six film layers at a center point of said perforation line.  
   
   
       26 . The apparatus for making a tri-fold bag roll, as described in  claim 24 , further comprising a supply of cores, said compact bag web being wound around said cores to form said compact bag rolls.  
   
   
       27 . The apparatus for making a tri-fold bag roll, as described in  claim 24 , further comprising a gusseter, said gusseter capable of forming at least one side gusset in said continuous tube prior to flattening.  
   
   
       28 . The apparatus for making a tri-fold bag roll, as described in  claim 24 , further comprising a corona treater, said corona treater capable of corona treating at least one upper and lower surface of said continuous bag web prior to folding.  
   
   
       29 . The apparatus for making a tri-fold bag roll, as described in  claim 28 , further comprising a printer, said printer capable of printing on at least one of said upper and lower surfaces of said continuous bag web after corona treatment.