Product containing an anionic cellulose derivative and its use in paper industry

Abstract

A product includes a microfibrillated cellulose composition, a starch derivative, and an anionic cellulose derivative, as a combined preparation for simultaneous or separate use. The anionic cellulose derivative has a number average molecular weight comprised between 300000 g/mol and 800000 g/mol, and a degree of substitution comprised between 0.3 and 0.65. Additionally, a paper sheet includes the product as an additive to increase the initial wet web strength and/or dry tensile strength of the paper sheet.

1 . A product comprising:
 a microfibrillated cellulose composition,   a starch derivative, and   an anionic cellulose derivative having a number average molecular weight comprised between 300000 g/mol and 800000 g/mol, and a degree of substitution comprised between 0.3 and 0.65,   as a combined preparation for simultaneous or separate use.   
     
     
         2 . The product of  claim 1 , wherein the microfibrillated cellulose of the microfibrillated cellulose composition is not chemically modified nor physically modified. 
     
     
         3 . The product of  claim 1 , wherein the starch derivative is a cationic starch. 
     
     
         4 . The product of  claim 1 , wherein the degree of substitution of the anionic cellulose derivative is comprised between 0.45 and 0.5. 
     
     
         5 . An admixture composition comprising:
 an aqueous pulp mixture,   a microfibrillated cellulose composition,   a starch derivative, and   an anionic cellulose derivative having a number average molecular weight comprised between 300000 g/mol and 800000 g/mol, and a degree of substitution comprised between 0.3 and 0.65.   
     
     
         6 . The admixture composition of  claim 5 , wherein the aqueous pulp mixture comprises at least 80 wt % of short fibers, relative to a total weight of fibers. 
     
     
         7 . The admixture composition of  claim 5 , wherein the microfibrillated cellulose of the microfibrillated cellulose composition is not chemically modified nor physically modified. 
     
     
         8 . The admixture composition of  claim 5 , wherein the starch derivative is a cationic starch. 
     
     
         9 . The admixture composition of  claim 5 , wherein the degree of substitution of the anionic cellulose derivative is comprised between 0.45 and 0.5. 
     
     
         10 . The admixture composition of  claim 5 , further comprising a retention system. 
     
     
         11 . The admixture composition of  claim 10 , wherein the retention system comprises at least one cationic polyacrylamide. 
     
     
         12 . The admixture composition of  claim 5 , wherein an amount of microfibrillated cellulose composition is comprised between 0.3 wt % and 5 wt %, based on a dry solid content of the microfibrillated cellulose composition relative to a dry solid content of the aqueous pulp mixture. 
     
     
         13 . The admixture composition of  claim 5 , wherein an amount of starch derivative is comprised between 0.1 wt % and 2 wt %, based on a dry solid content of the starch derivative relative to a dry solid content of the aqueous pulp mixture. 
     
     
         14 . The admixture composition of  claim 5 , wherein an amount of anionic cellulose derivative is comprised between 0.05 wt % and 0.3 wt %, based on a dry solid content of the anionic cellulose derivative relative to a dry solid content of the aqueous pulp mixture. 
     
     
         15 . A method for preparing the admixture composition of  claim 5 , comprising:
 providing the aqueous pulp mixture, and   admixing to the aqueous pulp mixture, the microfibrillated cellulose composition, the starch derivative, and the anionic cellulose derivative, and.   
     
     
         16 . The method of  claim 15 , wherein the aqueous pulp mixture has a solid content of less than 3% of a total solids content in the aqueous pulp mixture. 
     
     
         17 . The method of  claim 15 , wherein the retention system of the admixture composition comprises at least one of cationic polyacrylamide and silica. 
     
     
         18 . A method for preparing a paper product, comprising:
 providing an aqueous pulp mixture,   admixing to the aqueous pulp mixture, a microfibrillated cellulose composition, a starch derivative and an anionic cellulose derivative, to form the admixture composition of  claim 5 , and   forming a wet sheet by draining the admixture composition, and.   
     
     
         19 . The method of  claim 18 , wherein the anionic cellulose derivative is added to the aqueous pulp mixture at least 10 minutes before a wet sheet formation. 
     
     
         20 . A paper product comprising a microfibrillated cellulose composition, a starch derivative, and an anionic cellulose derivative having a number average molecular weight comprised between 300000 g/mol and 800000 g/mol, and a degree of substitution comprised between 0.3 and 0.65. 
     
     
         21 . A paper sheet comprising the product of  claim 1 , as an additive to increase at least one of an initial wet web strength and a dry tensile strength of the paper sheet. 
     
     
         22 . The method of  claim 15 , further comprising admixing a retention system. 
     
     
         23 . The method of  claim 16 , wherein the aqueous pulp mixture has a solid content of less than 3% of a total solids content in the aqueous pulp mixture. 
     
     
         24 . The method of  claim 20 , further comprising admixing a retention system to form the admixture composition.