Microfibrillated cellulose with enhanced properties and methods of making the same

Patent metadata

Field	Value
Publication number	US-11242651-B2
Application number	US-201816605355-A
Country	US
Kind code	B2
Filing date	Apr 20, 2018
Priority date	Apr 21, 2017
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

Methods of re-dispersing and de-agglomerating dewatered, partially dried and dried compositions of microfibrillated cellulose and compositions of microfibrillated cellulose and inorganic particulate material, into liquid compositions comprising same, by applying ultrasonic energy to such liquid compositions of dewatered, partially dried and dried compositions of microfibrillated cellulose, or compositions of microfibrillated cellulose and inorganic particulate material. Methods for preparing an aqueous suspension comprising microfibrillated cellulose and, optionally, inorganic particulate material, with enhanced viscosity and tensile strength properties, suitable for use in methods of making paper or coating paper, and to filled and coated papers made from such aqueous suspensions.

First claim

We claim:

1. A method for re-dispersing dewatered, partially dried or essentially dried microfibrillated cellulose, the method comprising the steps of:
(a) adding a quantity of a suitable dispersing liquid to a tank having at least a first and a second inlet and an outlet, wherein the tank further comprises a mixer and a pump attached to the outlet;
(b) adding a quantity of dewatered, partially dried or essentially dried microfibrillated cellulose to the tank through the first inlet in sufficient quantity to yield a liquid composition of microfibrillated cellulose at a desired solids concentration of 0.5 to 5% fibre solids;
(c) mixing the dispersing liquid and the dewatered, partially dried or essentially dried microfibrillated cellulose in the tank with the mixer to partially de-agglomerate and re-disperse the microfibrillated cellulose to form a flowable slurry;
(d) pumping the flowable slurry with the pump to an inlet of a flow cell, wherein the flow cell comprises a recirculation loop and one or more sonication probe in series and at least a first and a second outlet, wherein the second outlet of the flow cell is connected to the second inlet of the tank, thereby providing for a continuous recirculation loop providing for the continuous application of ultrasonic energy to the slurry for a desired time period and/or total energy, wherein the flow cell comprises an adjustable valve at the second outlet to create back pressure of the recirculated slurry, further wherein the liquid composition comprising microfibrillated cellulose of step (c) is continuously recirculated through the recirculation loop at an operating pressure of 0 to 4 bar and at a temperature of 20° C. to 50° C.;
(e) applying an ultrasonic energy input to the slurry of 200 to 10,000 kWh/t continuously by the sonication probe at a frequency range of 19 to 100 kHz and at an amplitude of up to 100% to the physical limitations of the sonicator used for 1 to 120 minutes;
(f) collecting the re-dispersed slurry comprising microfibrillated cellulose with enhanced tensile strength and/or viscosity properties from the first outlet of the flow cell in a suitable holding vessel.

2. The method of claim 1 , wherein the dewatered, partially dried or essentially dried microfibrillated cellulose composition further comprises at least one inorganic particulate material.

3. The method of claim 2 , wherein the dispersing liquid is water.

4. The method of claim 1 , wherein the dispersing liquid is water.

5. The method of claim 4 , wherein the ultrasonic energy is applied until a cumulative ultrasonic energy input of 2,500 kWh/tis achieved.

6. The method of claim 1 , wherein the ultrasonic energy input is from about 1,000 kWh/t to about 2,000 kWh/t.

7. The method of claim 2 , wherein the ultrasonic energy input is from about 1,000 kWh/t to about 2,000 kWh/t.

8. The method of claim 1 , wherein the ultrasonic energy input is from about 200 kWh/t to about 400 kWh/t.

9. The method of claim 2 , wherein the ultrasonic energy input is from about 200 kWh/t to about 400 kWh/t.

10. The method of claim 1 , wherein the flow cell has a cooling jacket for maintaining a temperature of the suspension of microfibrillated cellulose in the range of about 20° C. to about 50° C.

11. The method of claim 2 , wherein the flow cell has a cooling jacket for maintaining a temperature of the suspension of microfibrillated cellulose in the range of about 20° C. to about 50° C.

12. The method of claim 1 , wherein the temperature is room temperature.

13. The method of claim 2 , wherein the temperature is room temperature.

14. The method of claim 1 , wherein the temperature is 20° C.

15. The method of claim 2 , wherein the temperature is 20° C.

16. The method of claim 1 , wherein the back pressure of the recirculated liquid is 3 bar.

17. The method of claim 2 , wherein the back pressure of the recirculated liquid is 3 bar.

18. The method of claim 1 , wherein the flow cell further comprises one or more boosters to mechanically increase or decrease the amplitude of the at least one sonication probe.

19. The method of claim 2 , wherein the flow cell further comprises one or more boosters to mechanically increase or decrease the amplitude of the at least one sonication probe.

20. The method of claim 1 , wherein the liquid composition of microfibrillated cellulose is about 0.5% to about 1%.

21. The method of claim 2 , wherein the liquid composition of microfibrillated cellulose is about 0.5% to about 1%.

22. The method of claim 1 , wherein the liquid composition of microfibrillated cellulose is about 1.5% fibre solids.

23. The method of claim 2 , wherein the liquid composition of microfibrillated cellulose is about 1.5% fibre solids.

24. The method of claim 1 , wherein the liquid composition of microfibrillated cellulose is about 1.8% fibre solids.

25. The method of claim 2 , wherein the liquid composition of microfibrillated cellulose is about 1.8% fibre solids.

26. The method of claim 1 , wherein the liquid composition of microfibrillated cellulose is about 2.5% fibre solids.

27. The method of claim 2 , wherein the liquid composition of microfibrillated cellulose is about 2.5% fibre solids.

28. The method of claim 1 , wherein the liquid composition of microfibrillated cellulose is about 2.5% fibre solids.

29. The method of claim 2 , wherein the liquid composition of microfibrillated cellulose is about 2.5% fibre solids.

30. The method of claim 1 , wherein the microfibrillated cellulose is pelletized.

31. The method of claim 2 wherein the microfibrillated cellulose composition comprising inorganic particulate material is pelletized.

32. The method of claim 1 , wherein the ultrasonic energy is applied for about 30 minutes.

33. The method of claim 2 , wherein the ultrasonic energy is applied for about 30 minutes.

34. The method of claim 1 , wherein the ultrasonic energy is applied until a specified ultrasonic energy input is achieved greater than 200 kWh/t.

35. The method of claim 2 , wherein the ultrasonic energy is applied until a specified ultrasonic energy input is achieved greater than 200 kWh/t.

36. The method of claim 1 , wherein the ultrasonic energy is applied until a specified cumulative ultrasonic energy input greater than 400 kWh/t is achieved.

37. The method of claim 2 , wherein the ultrasonic energy is applied until a specified cumulative energy input greater than 400 kWh/t is achieved.

38. The method of claim 1 , wherein the ultrasonic energy is applied until a cumulative ultrasonic energy input of 500 kWh/tis achieved.

39. The method of claim 2 , wherein the ultrasonic energy is applied until a cumulative ultrasonic energy input of 500 kWh/tis achieved.

40. The method of claim 1 , wherein the ultrasonic energy is applied until a cumulative ultrasonic energy input of 1,000 kWh/t is achieved.

41. The method of claim 2 , wherein the ultrasonic energy is applied until a cumulative ultrasonic energy input of 1,000 kWh/t is achieved.

42. The method of claim 1 , wherein the ultrasonic energy is applied until a cumulative ult

Assignees

• Fiberlean Tech Ltd

Inventors

• Windebank Mark
• Skuse David
• Motsi Tafadzwa
• Tellier Guillaume

Classifications

• D21H19/34

  comprising cellulose or derivatives thereof · CPC title

• D21H19/385

  Oxides, hydroxides or carbonates · CPC title

• D21C9/007

  by mechanical or physical means · CPC title

• D21H17/69

  modified, e.g. by association with other compositions prior to incorporation in the pulp or paper · CPC title

• D21H19/52

  Cellulose; Derivatives thereof · CPC title