Reinforcing strips for corrugated paperboard and related method and apparatus for its manufacture

Abstract

Reinforcing packaging strips comprised of low melt point, low density polyethylene coated on at least one surface of a substrate. Corrugated paperboard packaging comprising a fluted paperboard medium having in selected areas a reinforcing liner, wherein said reinforcing liner has an adhesive surface which when heat activated adheres to the medium surface. The resulting structure has high strength and tear resistance in designated areas.

1 . Reinforcing packaging strips comprised of low melt point, low density polyethylene coated on at least one surface of a paper substrate. 
   
   
       2 . A reinforced corrugated paperboard substrate suitable for the manufacture of packaging, comprising:
 a top paperboard liner including a top and bottom surface;   a fluted paperboard medium including a top and bottom surface, wherein the flute tips of the top surface of said medium are adhered to the bottom surface of said top liner;   a reinforcing liner including a top and bottom surface, wherein the top surface of said reinforcing liner is adhered to the bottom flute tips of said medium, said reinforcing liner having a width less than the width of said medium;   an adhesive covering the bottom surface of said reinforcing liner; and   a bottom paperboard liner including a top and bottom surface, top surface of said bottom liner adhered to bottom surface of said reinforcing liner by means of said adhesive therebetween.   
   
   
       3 . The reinforced corrugated paperboard substrate according to  claim 2 , wherein said adhesive is a heat activated compound activated by ambient heat present in the hot plate section. 
   
   
       4 . The reinforced corrugated paperboard substrate according to  claim 3 , wherein said heat-activated adhesive is a thermoplastic material with a melting point below 250° F. 
   
   
       5 . The reinforced corrugated paperboard substrate according to  claim 4 , wherein said thermoplastic material is a low-density polyethylene resin. 
   
   
       6 . The reinforced corrugated paperboard substrate according to  claim 5 , wherein said low-density polyethylene resin has a coating weight in the range of 5.0-20.0 lbs./3000 sq. ft. 
   
   
       7 . The reinforced corrugated paperboard substrate according to  claim 5 , wherein said low-density polyethylene resin has a density in the range of 0.90-1.00 g./cm 3 . 
   
   
       8 . The reinforced corrugated paperboard substrate according to  claim 3 , wherein said heat-activated adhesive is a thermosetting material with a melting point below 250° F. 
   
   
       9 . A method of manufacturing reinforced corrugated paperboard comprising the steps of:
 providing a continuous web of corrugated paperboard;   feeding a reinforcing liner comprising a heat activated adhesive coated on at least one surface of a paper substrate over selective areas of said corrugated paperboard to form a laminated structure;   heating said laminated structure to a temperature high enough to melt said heat activated adhesive causing said liner to adhere to the corrugated paperboard in the selected areas.   
   
   
       10 . The method according to  claim 9 , wherein said heat activated adhesive is a thermoplastic material with a melting point below 250° F. 
   
   
       11 . The method according to  claim 10 , wherein said thermoplastic material is a low-density polyethylene resin. 
   
   
       12 . The method according to  claim 11 , wherein the said low-density polyethylene resin has a coating weight in the range of 5.0-20 lbs./3000 sq. ft. 
   
   
       13 . The method according to  claim 10 , wherein the said low-density polyethylene resin has a density in the range of 0.90-1.00 g./cm 3 . 
   
   
       14 . The method of  claim 9 , wherein said heat activated adhesive is a thermosetting material with a melting point below 250° F. 
   
   
       15 . An apparatus for manufacturing reinforced corrugated paperboard comprising:
 first supply means for providing a continuous web of corrugated paperboard;   second supply means for providing a liner having an adhesive coating on at least one surface,   placement means for placing said liner on selective areas of said paperboard;   reinforcing means for adhering said liner to said selective areas of the paperboard.   
   
   
       16 . The apparatus according to claim wherein said reinforcing means is a hot plate.