Surface enhanced pulp fibers, methods of making surface enhanced pulp fibers, products incorporating surface enhanced pulp fibers, and methods of making products incorporating surface enhanced pulp fibers
Various embodiments of the present invention relate to surface enhanced pulp fibers, various products incorporating surface enhanced pulp fibers, and methods and systems for producing surface enhanced pulp fibers. Various embodiments of surface enhanced pulp fibers have significantly increased surface areas compared to conventional refined fibers while advantageously minimizing reductions in length following refinement. The surface enhanced pulp fibers can be incorporated into a number of products that might benefit from such properties including, for example, paper products, paperboard products, fiber cement boards, fiber reinforced plastics, fluff pulps, hydrogels, cellulose acetate products, and carboxymethyl cellulose products. In some embodiments, a plurality of surface enhanced pulp fibers have a length weighted average fiber length of at least about 0.3 millimeters and an average hydrodynamic specific surface area of at least about 10 square meters per gram, wherein the number of surface enhanced pulp fibers is at least 12,000 fibers/milligram on an oven-dry basis.
1. A method for producing pulp fibers, the method comprising:
introducing a plurality of pulp fibers in a mechanical refiner comprising a pair of refiner plates, wherein each of the plates has a bar width of 1.3 millimeters or less and a groove width of 2.5 millimeters or less, and wherein the refiner operates at a specific edge load between 0.1 and 0.3 Ws/m; and
refining the pulp fibers until an energy consumption of at least 300 kWh/ton for the refiner is reached to produce a plurality of surface enhanced pulp fibers.
2. The method of claim 1 , wherein each of the plates has a bar width of 1.0 millimeters or less and a groove width of 1.6 millimeters or less.
3. The method of claim 1 , wherein the pulp fibers are refined until an energy consumption of at least 450 kWh/ton for the refiner is reached.
4. The method of claim 1 , wherein the pulp fibers are refined until an energy consumption of at least 650 kWh/ton for the refiner is reached.
5. The method of claim 1 , wherein the pulp fibers are refined until an energy consumption between 300 kWh/ton and 650 kWh/ton for the refiner is reached.
6. The method of claim 1 , wherein the pulp fibers are refined until an energy consumption between 450 kWh/ton and 650 kWh/ton for the refiner is reached.
7. The method of claim 1 , wherein the pulp fibers are in one or more bales prior to introduction in the mechanical refiner.
8. The method of claim 1 , wherein the pulp fibers are in a slushed condition prior to introduction in the mechanical refiner.
9. The method of claim 1 , wherein the refining comprises recirculating the pulp fibers through the refiner a plurality of times until an energy consumption of at least 300 kWh/ton for the refiner is reached.
10. The method of claim 9 , wherein the pulp fibers circulate through the refiner at least three times.
11. The method of claim 1 , wherein the surface enhanced pulp fibers have a length weighted average length that is at least 60% of the length weighted average length of the pulp fibers and an average hydrodynamic specific surface area that is at least 4 times greater than the average specific surface area of the pulp fibers.
12. The method of claim 1 , wherein the surface enhanced pulp fibers have an average hydrodynamic specific surface area that is at least 4 times greater than the average specific surface area of the pulp fibers.
13. The method of claim 1 , wherein the pulp fibers comprise hardwood fibers and the surface enhanced pulp fibers have a length weighted average fiber length of at least 0.35 millimeters and an average hydrodynamic specific surface area of at least 12 square meters per gram.
14. The method of claim 1 , wherein the pulp fibers comprise hardwood fibers and the surface enhanced pulp fibers have a length weighted average fiber length of at least 0.3 millimeters and an average hydrodynamic specific surface area of at least 10 square meters per gram.
15. The method of claim 14 , wherein the surface enhanced pulp fibers have a length weighted average fiber length of at least 0.4 millimeters.
16. The method of claim 14 , wherein the surface enhanced pulp fibers have an average hydrodynamic specific surface area of at least 12 square meters per gram.
17. The method of claim 1 , wherein refining the pulp fibers comprises:
continuously removing a plurality of pulp fibers from the mechanical refiner, wherein a portion of the removed pulp fibers comprises at least some of the surface enhanced pulp fibers; and
recirculating greater than 80% of the removed pulp fibers back to the mechanical refiner for further refining.
18. A method for producing pulp fibers, the method comprising:
introducing a plurality of pulp fibers into at least one first refiner comprising a pair of refiner plates, wherein each of the plates has a bar width of 1.3 millimeters or less and a groove width of 2.5 millimeters or less;
refining the pulp fibers in the first refiner(s) to produce a plurality of fibrillated fibers;
transporting the fibrillated fibers to at least one additional refiner comprising a pair of refiner plates, wherein each of the plates has a bar width of 1.3 millimeters or less and a groove width of 2.5 millimeters or less, and wherein each of the additional refiner(s) operates at a specific edge load between 0.1 and 0.3 Ws/m; and
refining the fibrillated fibers in the additional refiner(s) until a total energy consumption of at least 300 kWh/ton for the first refiner(s) and additional refiner(s) is reached to produce a plurality of surface enhanced pulp fibers.
19. The method of claim 18 , wherein the pulp fibers are refined in the first refiner(s) by recirculating at least a portion of the pulp fibers through each of the first refiner(s) a plurality of times.
20. The method of claim 18 , wherein the fibrillated fibers are refined in the additional refiner(s) by recirculating the fibrillated fibers through each of the additional refiner(s) a plurality of times until a total energy consumption of at least 300 kWh/ton for the first refiner(s) and additional refiner(s) is reached.
21. The method of claim 18 , wherein the fibrillated fibers are refined in the additional refiner(s) by recirculating the fibrillated fibers through each of the additional refiner(s) a plurality of times until a total energy consumption of at least 450 kWh/ton for the first refiner(s) and additional refiner(s) is reached.
22. The method of claim 18 , wherein the fibrillated fibers are refined in the additional refiner(s) by recirculating the fibrillated fibers through each of the additional refiner(s) a plurality of times until a total energy consumption of at least 650 kWh/ton for the first refiner(s) and additional refiner(s) is reached.
23. The method of claim 18 , wherein each of the refiner plates in each of the first mechanical refiner(s) has a bar width of greater than 1.0 millimeters and a groove width of greater or equal to 2.0 millimeters, and each of the refiner plates in each of the additional mechanical refiner(s) has a bar width of 1.0 millimeters or less and a groove width of 1.6 millimeters or less.
24. The method of claim 18 , wherein the pulp fibers comprise hardwood fibers and the surface enhanced pulp fibers have a length weighted average fiber length of at least 0.35 millimeters and an average hydrodynamic specific surface area of at least 12 square meters per gram.
25. The method of claim 18 , wherein the pulp fibers comprise hardwood fibers and the surface enhanced pulp fibers have a length weighted average fiber length of at least 0.3 millimeters and an average hydrodynamic specific surface area of at least 10 square meters per gram.
26. The method of claim 25 , wherein the surface enhanced pulp fibers have a length weighted average fiber length of at least 0.4 millimeters.
27. The method of claim 25 , wherein the surface enhanced pulp fibers have an average hydrodynamic specific surface area of at least 12 square meters per gram.