Dry processed cellulose fibers for papermaking

Abstract

Dry processing of cellulose fibers in an attritor mill produces small cellulose particles with properties useful for increasing the bulk of paperboard products. In contrast with the usual behaviour of small particles, the dry attritor-processed particles exhibit a further benefit of good drainage on a paper machine. Comparisons are made for the modulus, smoothness, and density of paperboard made with and without the dry-attrited cellulose particles.

1 . A composition, comprising:
 a dry processed collection of cellulose particles having a particle size distribution, wherein 95% of the particles are between 20 microns and 500 microns.   
     
     
         2 . The composition of  claim 1 , wherein the cellulose particles show no tendency to hydrate. 
     
     
         3 . The composition of  claim 1 , wherein 90% of the particles are between 25 and 350 microns. 
     
     
         4 . The composition of  claim 1 , wherein 80% of the particles are between 35 and 300 microns. 
     
     
         5 . The composition of  claim 1 , where substantially all of the particles are between 10 and 1000 microns. 
     
     
         6 . The composition of  claim 1 , wherein the particle size distribution is a unimodal distribution. 
     
     
         7 . The composition of  claim 1 , wherein the cellulose particles are softwood. 
     
     
         8 . The composition of  claim 7 , wherein the cellulose particles are unbleached. 
     
     
         9 . The composition of  claim 7 , wherein the cellulose particles are bleached. 
     
     
         10 . The composition of  claim 1 , wherein the cellulose particles are hardwood. 
     
     
         11 . A specialized papermaking furnish, comprising:
 a cellulosic composition comprising a dry processed collection of cellulose particles having a particle size distribution, wherein 95% of the particles are between 20 microns and 500 microns; and   a conventionally refined papermaking furnish;   wherein the cellulosic composition is used in an amount between 3 20 parts per 90 parts of the conventionally refined papermaking furnish.   
     
     
         12 . The specialized papermaking furnish of  claim 11 , wherein the cellulosic composition is used in an amount between 5 15 parts per 90 parts of conventionally refined papermaking furnish. 
     
     
         13 . The specialized papermaking furnish of  claim 11 , wherein the cellulosic composition is used in an amount between 8 12 parts per 90 parts of conventionally refined papermaking furnish. 
     
     
         14 . A raw stock comprising the composition of  claim 1 . 
     
     
         15 . A base stock comprising the composition of  claim 1 . 
     
     
         16 . A paperboard comprising the composition of  claim 1 . 
     
     
         17 . A multi-ply paperboard having a plurality of plies, wherein at least one ply comprises the composition of  claim 1 . 
     
     
         18 . The multi-ply paperboard of  claim 17 , wherein at least one ply does not contain the cellulose particles. 
     
     
         19 . A process for making a cellulosic composition, comprising:
 providing an attritor device;
 introducing dry cellulose fibers into the attritor device, the dry cellulose fibers having an initial size distribution; 
 subjecting the dry cellulose fibers to communition in the attritor device to create smaller cellulose particles; and 
 collecting the cellulose particles that are below a specific size. 
   
     
     
         20 . The process of  claim 19 , wherein the mean particle size of the cellulose fibers following communition is not more than 50% that of the cellulose fibers when introduced to the attritor device. 
     
     
         21 . The process of  claim 19 , wherein the specific size is 1000 microns. 
     
     
         22 . The process of  claim 19 , wherein the collected cellulose particles have a particle size distribution with 95% of the particles between 20 microns and 500 microns. 
     
     
         23 . The process of  claim 19 , further comprising the addition of the collected cellulose particles in an amount between 3-20 parts to 90 parts of a conventionally papermaking furnish to create a specialized papermaking furnish. 
     
     
         24 . The process of  claim 23 , further comprising forming the specialized papermaking furnish into a web. 
     
     
         25 . The process of  claim 24 , wherein the web comprises at least two plies. 
     
     
         26 . The process of  claim 25 , wherein at least one ply does not contain the cellulose particles. 
     
     
         27 . The process of  claim 24 , further comprising coating the web to improve its smoothness.