Modified filler composition, pulp and paper using same

1. A modified filler composition, comprising:

filler having negative charge;

microfibrillated cellulose (MFC) having a dry weight of 0.1% to 10% of that of the filler, the microfibrillated cellulose being made by TEMPO catalytic oxidation method; and

cationic polymer having a dry weight of 0.1% to 15% of that of the filler;

wherein the microfibrillated cellulose has a carboxyl content of 0.06 to 1.7 mmol/g;

the microfibrillated cellulose comprises water-soluble cellulose having a mass percentage on a dry solids basis of 0.1% to 50% and water-insoluble cellulose having a mass percentage on a dry solids basis of 10% to 99.9%.

2. The modified filler composition as claimed in claim 1 , wherein the water-soluble celluloses comprises nanocrystalline cellulose, nanofibrillated cellulose, and oligosaccharide.

3. The modified filler composition as claimed in claim 1 , wherein the filler is surface modified by a dispersant, the dispersant has a weight of 0.001% to 5% of that of the filler; and the dispersant is selected from sodium polyacrylate, sodium polycarboxylic acid, sodium poly-allylsulfonate, and derivatives thereof.

4. The modified filler composition as claimed in claim 1 , wherein the cationic polymer is selected from cationic polysaccharide, cationic polyacrylamide, polyvinylamine, polyethylene imine, and derivatives thereof.

5. The modified filler composition as claimed in claim 1 , wherein the cationic polymer has a molecular weight between 2×10 3 and 2×10 6 .

6. The modified filler composition as claimed in claim 5 , wherein the cationic polymer has a molecular weight between 2×10 4 and 1×10 6 .

7. The modified filler composition as claimed in claim 1 , wherein the filler adsorbing on the surface of the MFC has a particle size uniformity of less than 10.

8. The modified filler composition as claimed in claim 1 , wherein more than 60% of the filler by weight has a particle diameter less than or equal to 2 μm.

9. The modified filler composition as claimed in claim 1 , wherein the modified filler composition further comprises a cross-linking agent, wherein the cross-linking agent is a borate cross-linking agent, a borax cross-linking agent, or dialdehyde cross-linking agent; and the dry weight of the cross-linking agent is about 0.1% to about 15% of that of the cationic polymer.

10. A pulp, comprising:

a modified filler composition, the modified filler composition comprising:

filler having negative charge;

microfibrillated cellulose having a dry weight of 0.1% to 10% of that of the filler, the microfibrillated cellulose being made by TEMPO catalytic oxidation method; and

cationic polymer having a dry weight of 0.1% to 15% of that of the filler;

wherein the microfibrillated cellulose has negative charge and has a carboxyl content of about 0.06 to about 1.7 mmol/g; the microfibrillated cellulose comprises water-soluble cellulose having a mass percentage on a dry solids basis of 0.1% to 50% and water-insoluble cellulose having a mass percentage on a dry solids basis of 10% to 99.9%.

11. The pulp as claimed in claim 10 , wherein the water-soluble celluloses comprises nanocrystalline cellulose, nanofibrillated cellulose, and oligosaccharide.

12. The pulp as claimed in claim 10 , wherein the filler is surface modified by a dispersant to make the filler having negative particle charge, the dispersant has a weight of 0.001% to 5% of that of the filler; the dispersant is selected from sodium polyacrylate, sodium polycarboxylic acid, sodium poly-allylsulfonate, and derivatives thereof.

13. The pulp as claimed in claim 10 , wherein the cationic polymer is selected from cationic polysaccharide, cationic polyacrylamide, polyvinylamine, polyethylene imine, and derivatives thereof.

14. The pulp as claimed in claim 10 , wherein the pulp comprises filler, and the filler is either all from the modified filler composition, or is a combination of the modified filler composition and the unmodified filler; the total weight of the filler added into the paper pulp is 10% to 300% of the dry weight of the pulp fiber; and the weight of filler from the modified filler composition is 90% to 100% of the total weight of the filler in the pulp.

15. The pulp as claimed in claim 10 , wherein the modified filler composition further comprises a cross-linking agent, wherein the cross-linking agent is a borate cross-linking agent, a borax cross-linking agent, or dialdehyde cross-linking agent; and the dry weight of the cross-linking agent is 0.1% to 15% of that of the cationic polymer.

16. The pulp as claimed in claim 10 , wherein the pulp further comprises starch and retention aids.

17. A paper, comprising:

a modified filler composition, the modified filler composition comprising:

filler having negative charge;

microfibrillated cellulose having a dry weight of 0.1% to 10% of that of the filler, the microfibrillated cellulose being made by TEMPO catalytic oxidation method; and

cationic polymer having a dry weight of 0.1% to 15% of that of the filler;

wherein the microfibrillated cellulose has negative charge and has a carboxyl content of 0.06 to 1.7 mmol/g; the microfibrillated cellulose comprises water-soluble cellulose having a mass percentage on a dry solids basis of 0.1% to 50% and water-insoluble cellulose having a mass percentage on a dry solids basis of 10% to 99.9%.

18. The paper as claimed in claim 17 , wherein the paper has an ash retention of 70% to 99.9%, and a first-pass ash retention of 65% to 99.9%.

19. The paper as claimed in claim 17 , wherein the water-soluble celluloses comprises nanocrystalline cellulose, nanofibrillated cellulose, and oligosaccharide.

20. The paper as claimed in claim 17 , wherein the filler is surface modified by a dispersant to make the filler having negative particle charge, the dispersant has a weight of 0.001% to 5% of that of the filler; and the dispersant is selected from sodium polyacrylate, sodium polycarboxylic acid, sodium poly-allylsulfonate, and derivatives thereof.

21. The paper as claimed in claim 17 , wherein the cationic polymer is selected from cationic polysaccharide, cationic polyacrylamide, polyvinylamine, polyethylene imine, and derivatives thereof.

22. The paper as claimed in claim 17 , wherein the modified filler composition further comprises a cross-linking agent, the cross-linking agent is a borate cross-linking agent, a borax cross-linking agent, or dialdehyde cross-linking agent; and the dry weight of the cross-linking agent is 0.1% to 15% of that of the cationic polymer.