Filler-fiber composite

Abstract

The present invention relates to a filler-fiber composite, a process for its production, the use of such in the manufacture of paper or paperboard products and to paper produced therefrom. More particularly the invention relates to a filler-fiber composite in which the morphology and particle size of the mineral filler are established prior to the development of the bond to the fiber. Even more particularly, the present invention relates to a PCC filler-fiber composite, wherein the desired optical and physical properties of the paper produced therefrom are realized.

We claim:  
     
         1 . A filler-fiber composite comprising: 
 (a) feeding slake containing seed to a first stage reactor    (b) reacting the slake containing seed in the first stage reactor in the presence of carbon dioxide to produce a first partially converted calcium hydroxide calcium carbonate slurry    (c) reacting the first partially converted calcium hydroxide calcium carbonate slurry in a second stage reactor in the presence of carbon dioxide and a heel to produce a second partially converted calcium hydroxide calcium carbonate slurry and    (d) reacting the second partially converted calcium hydroxide calcium carbonate slurry in a third stage reactor in the presence of carbon dioxide and fibers to produce a filler-fiber composite.    
     
     
         2 . The filler-fiber composite of  claim 1  wherein the fiber is from about 0.1 microns to about 2 microns in thickness and from about 10 microns to about 400 microns in length.  
     
     
         3 . The filler-fiber composite of  claim 2  wherein the filler is aragonite and has a specific surface area of from about 5 meters squared per gram to about 11 meters squared per gram.  
     
     
         5 . The filler-fiber composite of claim  4  wherein the first partially converted calcium hydroxide calcium carbonate slurry is converted from about 41 percent to about 99 percent.  
     
     
         6 . The filler-fiber composite of  claim 5  wherein the second partially converted calcium hydroxide calcium carbonate slurry is converted to a filler-fiber composite.  
     
     
         7 . A method for producing a filler-fiber composite comprising: 
 (a) feeding slake containing citric acid to a first stage reactor    (e) reacting the slake containing citric acid in the first stage reactor in the presence of carbon dioxide to produce a CaCO 3  heel and    (f) adding slake containing sodium carbonate to the heel material of the first stage reactor in the presence of CO 2 to produce a partially converted calcium hydroxide calcium carbonate slurry and    (g) reacting the partially converted calcium hydroxide calcium carbonate slurry in a second stage reactor in the presence of carbon dioxide and fibrils to produce a filler-fiber composite.    
     
     
         8 . The method for producing the filler-fiber composite of  claim 7  wherein the fiber is from about 0.1 microns to about 2 microns in thickness and from about 10 microns to about 400 microns in length.  
     
     
         9 . The method for producing the filler-fiber composite of  claim 8  wherein the filler is rhombohedral and has a specific surface area of from about 5 meters squared per gram to about 11 meters squared per gram.  
     
     
         10 . The method for producing the filler-fiber composite of  claim 9  wherein the calcium hydroxide calcium carbonate slurry is converted from about 20 percent to about 40 percent.  
     
     
         11 . The method for producing the filler-fiber composite of  claim 10  wherein the first partially converted calcium hydroxide calcium carbonate slurry is converted from about 41 percent to about 99 percent.  
     
     
         12 . The method for producing the filler-fiber composite of  claim 11  wherein the second partially converted calcium hydroxide calcium carbonate slurry is converted to a filler-fiber composite.  
     
     
         13 . The filler-fiber composite of  claim 1  utilized in paper or paperboard.  
     
     
         14 . The filler-fiber composite of  claim 7  utilized in paper or paperboard.  
     
     
         15 . The paper produced utilizing the filler-fiber of  claim 1 .  
     
     
         16 . The paper produced utilizing the filler-fiber of  claim 7.