Method for obtaining a fibrous preparation for immersion-resistant opaque paper

Abstract

A method for obtaining a fibrous preparation for manufacturing a paper having significant water repellency and opacity in the dry or wet state. Fibres are suspended in water; calcium salts are added to the fibres; a source of carbonate salts in the form of an aqueous solution are added and the resulting mixture is stirred for a time sufficient to allow calcium carbonate particles to be precipitated. A solution of fatty acid salts heated to a temperature which corresponds to the micellisation temperature of said fatty acid salts is added and takes into account the critical micellar concentration of the fatty acid salts. The mixture is stirred thus obtained for a time sufficient to allow the fatty acids to be absorbed at the surface of the calcium carbonate particles and to obtain the desired fibrous preparation.

1 - 13 . (canceled) 
     
     
         14 . A method for obtaining a fibrous preparation for manufacturing a paper having significant water repellency and opacity in the dry or wet state, comprising:
 suspending fibres in water,   adding calcium salts to said fibres,   adding a source of carbonate salts in the form of an aqueous solution,   stirring the resulting mixture for a time sufficient to allow calcium carbonate particles to be precipitated,   adding a solution of fatty acid salts heated to a temperature which corresponds to the micellisation temperature of said fatty acid salts and takes into account the critical micellar concentration of said fatty acid salts,   stirring the mixture thus obtained for a time sufficient to allow the fatty acids to be absorbed at the surface of the calcium carbonate particles and to obtain the desired fibrous preparation.   
     
     
         15 . The method for obtaining according to  claim 14 , wherein the final step is followed by a step of adding additives and/or dyes usually used in the paper industry to the fibrous preparation obtained. 
     
     
         16 . The method for obtaining according to  claim 14 , wherein the fibres are cellulose fibres. 
     
     
         17 . The method for obtaining according  claim 14 , wherein the calcium salts have either mineral counterions or organic counterions. 
     
     
         18 . Method for obtaining according to  claim 17 , wherein the calcium salts are calcium chloride. 
     
     
         19 . The method for obtaining according to  claim 14 , wherein the carbonate salts have metallic counterions or the carbonate salts can also be mineral or organic. 
     
     
         20 . The method for obtaining according to  claim 19 , wherein the carbonate salts are sodium carbonate. 
     
     
         21 . The method for obtaining according to  claim 14 , wherein the dosages of calcium salts and of carbonate salts used are advantageously determined to produce, by precipitation, a mass of calcium carbonate corresponding to at most 25% of the dry matter. 
     
     
         22 . The method for obtaining according to  claim 21 , wherein the mass of calcium carbonate produced corresponds to a value between 20 and 22% of the dry matter. 
     
     
         23 . The method for obtaining according to  claim 14 , wherein the fatty acid salts comprise between 12 and 22 carbons in their chain and their counterions can be metal or organic salts. 
     
     
         24 . The method for obtaining according to  claim 23 , wherein the fatty acid salts comprise 18 carbons in their chain and will be, preferably, potassium stearate. 
     
     
         25 . The method for obtaining according to  claim 24 , wherein the fatty acid salts are potassium stearate. 
     
     
         26 . A paper having significant water repellency and opacity in the dry or wet state, wherein the paper is manufactured from the fibrous preparation receiving calcium carbonate particles produced by precipitation and bound directly at the surface and/or in the fibres thereof, and fatty acids adsorbed at the surface of the calcium carbonate particles, and obtained with the method for obtaining according to  claim 14 . 
     
     
         27 . The method for obtaining according to  claim 15 , wherein the fibres are cellulose fibres. 
     
     
         28 . The method for obtaining according  claim 15 , wherein the calcium salts have either mineral counterions or organic counterions. 
     
     
         29 . The method for obtaining according  claim 16 , wherein the calcium salts have either mineral counterions or organic counterions. 
     
     
         30 . The method for obtaining according to  claim 15 , wherein the carbonate salts have metallic counterions or the carbonate salts can also be mineral or organic. 
     
     
         31 . The method for obtaining according to  claim 16 , wherein the carbonate salts have metallic counterions or the carbonate salts can also be mineral or organic. 
     
     
         32 . The method for obtaining according to  claim 17 , wherein the carbonate salts have metallic counterions or the carbonate salts can also be mineral or organic. 
     
     
         33 . The method for obtaining according to  claim 18 , wherein the carbonate salts have metallic counterions or the carbonate salts can also be mineral or organic.