Use of calcuim carbonate particles in papermaking

Abstract

A process for the production of paper by introducing a suspension of ultrafine calcium carbonate particles to a fiber-containing suspension. A method for improving the dewatering of a fiber-containing suspension. Use of a calcium carbonate suspension comprising ultrafine particles of calcium carbonate as a substitute for colloidal silica as a dewatering agent in the formation of paper from a fiber-containing suspension. At least one ionic polymer is introduced in the fiber-containing suspension.

1 - 10 . (canceled)  
   
   
       11 . A process for the production of paper, comprising the steps of: 
 (a) providing a fiber-containing suspension containing cellulose fibers, and optional fillers;    (b) introducing at least one suspension comprising ultrafine particles of calcium carbonate to the fiber-containing suspension, and    (c) forming and dewatering the fiber-containing suspension resulting from step (b),    wherein the ultrafine calcium carbonate particles have an average size lower than or equal to 200 nm.    
   
   
       12 . A method for improving the dewatering of a fiber-containing suspension containing cellulose-fibers, said method comprising the addition of a calcium carbonate suspension comprising ultrafine particles of calcium carbonate to a fiber-containing suspension containing cellulose-fibers, wherein the ultrafine calcium carbonate particles have an average size lower than or equal to 200 nm.  
   
   
       13 . A method which comprises the use of a calcium carbonate suspension comprising ultrafine particles of calcium carbonate as a substitute for colloidal silica as a dewatering agent in the formation of paper from a fiber-containing suspension containing cellulose-fibers, wherein the ultrafine calcium carbonate particles have an average size lower than or equal to 200 nm.  
   
   
       14 . The process according to  claim 11  wherein at least one ionic polymer is introduced into the fiber-containing suspension containing cellulose fibers.  
   
   
       15 . The process according to  claim 11  wherein the calcium carbonate is a precipitated calcium carbonate and wherein the calcium carbonate is calcite.  
   
   
       16 . The process according to  claim 11  wherein the content of ultrafine particles of calcium carbonate in the calcium carbonate suspension is higher than or equal to 1% by weight and lower than or equal to 70% by weight.  
   
   
       17 . The process according to  claim 11  wherein the ratio of the cationic polymer with respect to the calcium carbonate is higher than or equal to 0.1 wt/wt.  
   
   
       18 . The process according to  claim 11  wherein the amount of calcium carbonate in the fiber-containing suspension containing cellulose fibers is higher than or equal to 0.01% and lower than or equal to 50% by weight calculated as dry calcium carbonate on the sum of dry fibers and optional fillers.  
   
   
       19 . The process according to  claim 11  wherein the ionic polymer is a cationic polymer selected from the group consisting of cationic starch, cationic guar gum, cationic acrylamide based polymers, cationic polyethyleneimines, polyamidoamines and poly(diallyldimethyl ammonium chloride) or any mixture thereof.  
   
   
       20 . The process according to  claim 19  wherein said cationic starch is selected from the group consisting of starch tertiary aminoalkyl ether derivatives, starch quaternary ammonium ether derivatives, aminoethylated starches, starch cyanamide derivatives, starch anthranilates and cationic dialdehyde starch.  
   
   
       21 . The method according to  claim 12  wherein at least one ionic polymer is introduced into the fiber-containing suspension containing cellulose fibers.  
   
   
       22 . The method according to  claim 12  wherein the calcium carbonate is a precipitated calcium carbonate and wherein the calcium carbonate is calcite.  
   
   
       23 . The method according to  claim 12  wherein the content of ultrafine particles of calcium carbonate in the calcium carbonate suspension is higher than or equal to 1% by weight and lower than or equal to 70% by weight.  
   
   
       24 . The method according to  claim 12  wherein the ratio of the cationic polymer with respect to the calcium carbonate is higher than or equal to 0.1 wt/wt.  
   
   
       25 . The method according to  claim 12  wherein the amount of calcium carbonate in the fiber-containing suspension containing cellulose fibers is higher than or equal to 0.01% and lower than or equal to 50% by weight calculated as dry calcium carbonate on the sum of dry fibers and optional fillers.  
   
   
       26 . The method according to  claim 12  wherein the ionic polymer is a cationic polymer selected from the group consisting of cationic starch, cationic guar gum, cationic acrylamide based polymers, cationic polyethyleneimines, polyamidoamines and poly(diallyldimethyl ammonium chloride) or any mixture thereof.  
   
   
       27 . The method according to  claim 26  wherein said cationic starch is selected from the group consisting of starch tertiary aminoalkyl ether derivatives, starch quaternary ammonium ether derivatives, aminoethylated starches, starch cyanamide derivatives, starch anthranilates and cationic dialdehyde starch.  
   
   
       28 . The method according to  claim 13  wherein at least one ionic polymer is introduced into the fiber-containing suspension containing cellulose fibers.  
   
   
       29 . The method according to  claim 13  wherein the calcium carbonate is a precipitated calcium carbonate and wherein the calcium carbonate is calcite.  
   
   
       30 . The method according to  claim 13  wherein the content of ultrafine particles of calcium carbonate in the calcium carbonate suspension is higher than or equal to 1% by weight and lower than or equal to 70% by weight.  
   
   
       31 . The method according to  claim 13  wherein the ratio of the cationic polymer with respect to the calcium carbonate is higher than or equal to 0.1 wt/wt.  
   
   
       32 . The method according to  claim 13  wherein the amount of calcium carbonate in the fiber-containing suspension containing cellulose fibers is higher than or equal to 0.01% and lower than or equal to 50% by weight calculated as dry calcium carbonate on the sum of dry fibers and optional fillers.  
   
   
       33 . The method according to  claim 13  wherein the ionic polymer is a cationic polymer selected from the group consisting of cationic starch, cationic guar gum, cationic acrylamide based polymers, cationic polyethyleneimines, polyamidoamines and poly(diallyldimethyl ammonium chloride) or any mixture thereof.  
   
   
       34 . The method according to  claim 33  wherein said cationic starch is selected from the group consisting of starch tertiary aminoalkyl ether derivatives, starch quaternary ammonium ether derivatives, aminoethylated starches, starch cyanamide derivatives, starch anthranilates and cationic dialdehyde starch.