Granted Patent B2

US 12,325,959 · App. 18/051,147 · Granted Jun 10, 2025

Inventors: Harshad Pande (Pointe-Claire, CA); Bruno Marcoccia (Charlotte, NC)

Assignee: Domtar Paper Company, LLC

D21H17/675D21D1/20D21H11/20D21H21/10D21H25/005

Abstract

Claims (27)

1. A method of making a filler-loaded pulp composition for generating a paper product, the method comprising: introducing wood pulp fibers and a first plurality of filler particles into one or more refiners; and refining the wood pulp fibers and the first plurality of filler particles with the refiner(s), wherein in each of the refiner(s) the wood pulp fibers and the first plurality of filler particles are refined together, wherein at least one of the refiner(s) operates at a specific edge load that is between 0.10 and 0.30 Watt-seconds/meter, wherein the first plurality of filler particles are introduced into the refiner(s) at an addition point directly before a respective refiner inlet of the refiner(s), and wherein the paper product has an ash retention of between approximately 71.9% to 86.3%.

2. The method of claim 1 , wherein:

the first plurality of filler particles comprises crystals of precipitated calcium carbonate (PCC); and

an average particle size of the crystals of PCC is between 0.2 and 3.0 microns.

3. The method of claim 1 , wherein each of the refiner(s) comprises a pair of refiner plates that each has:

a bar width that is less than or equal to 1.3 millimeters; and

a groove width that is less than or equal to 2.5 millimeters.

4. The method of claim 1 , wherein no binders or retention aids are included in the filler-loaded pulp composition.

5. The method of claim 1 , wherein the ratio of the wood pulp fibers to the first plurality of filler particles introduced into the refiner(s) is between 1:5 and 1:1.

6. The method of claim 1 , wherein the ratio of the wood pulp fibers to the first plurality of filler particles introduced into the refiner(s) is between 1:3 and 1:1.

7. The method of claim 1 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed such that the refined wood pulp fibers have a length-weighted average fiber length that is at least 0.3 millimeters and an average hydrodynamic specific surface area that is at least 10 square meters per gram.

8. The method of claim 7 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed such that the refined wood pulp fibers have a fiber count that is at least 12,000 fibers per milligram on an oven-dry basis.

9. The method of claim 7 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed such that the refined wood pulp fibers have a length weighted average fiber length that is at least 0.4 millimeters and an average hydrodynamic specific surface area that is at least 12 square meters per gram.

10. The method of claim 1 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed such that a length weighted average length of the refined wood pulp fibers is at least 60% of the original length weighted average length of the wood pulp fibers prior to refining.

11. The method of claim 10 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed such that an average hydrodynamic specific surface area of the refined wood pulp fibers is at least 4 times greater than the average hydrodynamic specific surface area of the wood pulp fibers prior to refining.

12. The method of claim 1 , wherein:

the wood pulp fibers comprise hardwood pulp fibers; and

refining the wood pulp fibers and the first plurality of filler particles is performed until the refiner(s) consume at least 400 kilowatt-hours per ton of the wood pulp fibers.

13. The method of claim 1 , further comprising:

combining the refined wood pulp fibers and the refined first plurality of filler particles with a second plurality of filler particles,

wherein the first and second plurality of filler particles comprise calcium carbonate, talc, clay, a silica-based pigment, and/or an aluminum-based pigment.

14. The method of claim 1 , where the first plurality of filler particles comprise calcium carbonate, talc, clay, a silica-based pigment, and/or an aluminum-based pigment.

15. The method of claim 1 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed until the refiner(s) consume between 400 and 1,800 kilowatt-hours per ton of the wood pulp fibers.

16. The method of claim 1 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed until the refiner(s) consume at least 300 kilowatt-hours per ton of the wood pulp fibers, and wherein the paper product has an ash retention of approximately 71.9%.

17. The method of claim 1 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed until the refiner(s) consume at least 400 kilowatt-hours per ton of the wood pulp fibers, and wherein the paper product has an ash retention of approximately 79.4%.

18. The method of claim 1 , wherein refining the wood pulp fibers and the first plurality of filler particles is performed until the refiner(s) consume at least 500 kilowatt-hours per ton of the wood pulp fibers, and wherein the paper product has an ash retention of approximately 86.3%.

19. The method of claim 1 , wherein the paper product has an ash retention of between approximately 71.9% to 86.3% compared to a second paper product that has a respective ash retention of between approximately 69.3% to 83.4% when its respective plurality of filler particles are introduced to a respective refiner(s) at a respective addition point after an outlet value to a refined pulp tank.

Assignments (2)

Continuity (3)

References Cited (244)