Wet Embossed Paperboard and Method and Apparatus for Manufacturing Same

Abstract

A process for manufacturing an embossed paperboard comprising the steps of: forming a wet mat including more than 60 wt % of cellulose fibers; pressure molding, with at least one embossing roll, the wet mat having 20 to 70 wt % solid to create a nested surface texture thereon; and drying the embossed wet mat to obtain the embossed paperboard with a grammage ranging between 125 and 1500 grams per square meter.

1 . A process for manufacturing an embossed paperboard comprising the steps of:
 forming a wet mat including more than 60 wt % of cellulose fibers;   pressure molding, with at least one embossing roll, the wet mat having 20 to 70 wt % solid to create a nested surface texture thereon; and   drying the embossed wet mat to obtain the embossed paperboard with a grammage ranging between 125 and 1500 grams per square meter.   
     
     
         2 . A process as claimed in  claim 1 , wherein forming the wet mat comprises superposing 1 to 12 paper plies. 
     
     
         3 . A process as claimed in  claim 1 , wherein forming the wet mat comprises superposing 7 to 9 paper plies. 
     
     
         4 . A process as claimed in  claim 1 , wherein the pressure molding step comprises applying a pressure ranging between 50 and 600 pounds per linear inch (PLI). 
     
     
         5 . A process as claimed in  claim 1 , wherein the pressure molding step is carried out with two embossing rolls having spaced-apart knobs in meshing engagement, the two embossing rolls being synchronously rotated. 
     
     
         6 . A process as claimed in  claim 1 , comprising decelerating the wet mat for carrying the pressure molding step. 
     
     
         7 . A process as claimed in  claim 6 , comprising accelerating the wet mat for carrying the drying step. 
     
     
         8 . A process as claimed in  claim 1 , comprising withdrawing excess water while carrying the pressure molding step. 
     
     
         9 . A process as claimed in  claim 1 , wherein the solid content of the wet mat ranges between 35 and 55 wt % during the pressure molding step. 
     
     
         10 . A process as claimed in  claim 1 , wherein the wet mat comprises more than 80 wt % of cellulose fibers. 
     
     
         11 . A process as claimed in  claim 1 , wherein the wet mat comprises less than 30 wt % of inorganic fillers. 
     
     
         12 . A process as claimed in  claim 1 , wherein the cellulose fibers of the wet mat comprises more than 60 wt % of recycled fibers. 
     
     
         13 . A process as claimed in  claim 12 , wherein the recycled fibers comprises more than 40 wt % of old corrugated cardboard (OCC) fibers. 
     
     
         14 . A process as claimed in  claim 1 , wherein the embossed paperboard has a specific volume density ranging between 1 and 6 cubic centimeter per gram. 
     
     
         15 . A process as claimed in  claim 1 , wherein the embossed paperboard has a tensile strength ranging between 100 and 700 Newtons per inch. 
     
     
         16 . A process as claimed in  claim 1 , wherein the embossed paperboard has a thickness ranging between 250 and 5000 micrometers. 
     
     
         17 . A process as claimed in  claim 1 , wherein the embossed paperboard has a moisture content below 15 wt %. 
     
     
         18 . A process as claimed in  claim 1 , wherein embossed paperboard has a grammage ranging between 250 and 900 grams per square meter. 
     
     
         19 . An embossed paperboard comprising: a paper mat having a nested surface texture thereon created by pressure molding with at least one embossing roll when the paper mat contained between 20 to 70 wt % solid and then dried to contain less than 15 wt % of moisture content, the paper mat having more than 60 wt % of cellulose fibers and a grammage ranging between 125 and 1500 grams per square meter. 
     
     
         20 . An embossed paperboard as claimed in  claim 19 , comprising a number of superposed paper plies ranging between 1 and 12. 
     
     
         21 . An embossed paperboard as claimed in  claim 20 , wherein the number of superposed paper plies ranges between 7 and 9. 
     
     
         22 . An embossed paperboard as claimed in  claim 19 , wherein the paper mat comprises more than 80 wt % of cellulose fibers. 
     
     
         23 . An embossed paperboard as claimed in  claim 19 , wherein the cellulose fibers of the paper mat comprises more than 60 wt % of recycled fibers. 
     
     
         24 . An embossed paperboard as claimed in  claim 19 , wherein the paper mat has at least one of a specific volume density ranging between 1 and 6 cubic centimeter per gram, a tensile strength ranging between 100 and 700 Newtons per inch and a thickness ranging between 250 and 5000 micrometers. 
     
     
         25 . An embossed paperboard as claimed in  claim 19 , wherein the embossed paperboard has a moisture content below 10 wt %.