Method to manufacture paper

Abstract

The present invention relates to a paper or paperboard substrate containing fiber-filler complexes as well as methods of making and using the same.

1 ) A paper substrate, comprising 
 a plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average and having a filler attached thereto a portion of said plurality;    less than 50 wt % fibers that are less than 75 μm in length on average based upon the total weight of the substrate.    
   
   
       2 ) The paper substrate according to  claim 1 , wherein said plurality of fibers from hardwood species, softwood species are virgin fibers.  
   
   
       3 ) The paper substrate according to  claim 1 , wherein said plurality of fibers from hardwood species, softwood species have a Canadian Standard Freeness of from 300 to 600.  
   
   
       4 ) The paper substrate according to  claim 1 , wherein the fibers that are less than 75 μm in length on average are recycled fibers, recirculated fibers, waste fibers, or mixtures thereof.  
   
   
       5 ) The paper substrate according to  claim 1 , wherein the filler is attached at a filler to fiber weight ratio of from 0.3 to 8.  
   
   
       6 ) The paper substrate according to  claim 1 , wherein the filler is present in an amount of from 1 to 30 wt % based upon the total weight of the substrate.  
   
   
       7 ) The paper substrate according to  claim 1 , comprising from 0.1 to 20 wt % of the fibers that are less than 75 μm in length based upon the total weight of the substrate.  
   
   
       8 ) The paper substrate according to  claim 1 , wherein the filler is precipitated calcium carbonate.  
   
   
       9 ) The paper substrate according to  claim 1 , wherein the filler is precipitated in at least one shape of selected from the group consisting of cubic, scalenohdral, rhombic, and aragonite.  
   
   
       10 ) The paper substrate according to  claim 9 , wherein the filler has an average particle size of from 0.01 to 20 μm.  
   
   
       11 ) The paper substrate according to  claim 9 , wherein the filler has an average particle size of from 0.01 to 10 μm.  
   
   
       12 ) A method of making a paper substrate according to  claim 1 , comprising contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average and having a filler attached thereto a portion of said plurality with fibers that are less than 75 μm in length on average based upon the total weight of the substrate.  
   
   
       13 ) The method of  claim 12 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average with Ca(OH) 2  and/or CO 2  simultaneously and/or sequentially.    
   
   
       14 ) The method of  claim 13 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average in-line with Ca(OH) 2  to form a slurry having less than 5% solids.    
   
   
       15 ) The method of  claim 13 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average with CO 2  gas prior to contacting the plurality of fibers with Ca(OH) 2 .    
   
   
       16 ) The method of  claim 13 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average with CO 2  gas prior to contacting the plurality of fibers with Ca(OH) 2 .    
   
   
       17 ) The method of  claim 12 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average with Ca(OH) 2  and/or CO 2  simultaneously and/or sequentially at a pH of from 7.5 to 11.    
   
   
       18 ) The method of  claim 12 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average with Ca(OH) 2  and/or CO 2  simultaneously and/or sequentially in a tubular reactor, wherein CO 2  is added to the reactor at multiple addition points.    
   
   
       19 ) The method of  claim 12 , further comprising 
 contacting the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average with Ca(OH) 2  and/or CO 2  simultaneously and/or sequentially in a series of continuous stirring tank reactor, wherein CO 2  is added to each of the continuous stirring tank reactor in the series.    
   
   
       20 ) The method of  claim 12 , further comprising contacting both the plurality of fibers from hardwood species, softwood species or mixtures thereof that are greater than or equal to 75 μm in length on average and the fibers that are less than 75 μm in length on average with Ca(OH) 2  and/or CO 2  simultaneously and/or sequentially in a series of continuous stirring tank reactor, wherein CO 2  is added to each of the continuous stirring tank reactor in the series.