U.S. patent application number 14/775158 was filed with the patent office on 2016-02-04 for functionalized cellulose fibers for dewatering and energy efficiency improvements.
The applicant listed for this patent is AUBURN UNIVERSITY. Invention is credited to Burak AKSOY, William R. ASHURST, Marko HAKOVIRTA.
Application Number | 20160032529 14/775158 |
Document ID | / |
Family ID | 51581368 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160032529 |
Kind Code |
A1 |
HAKOVIRTA; Marko ; et
al. |
February 4, 2016 |
FUNCTIONALIZED CELLULOSE FIBERS FOR DEWATERING AND ENERGY
EFFICIENCY IMPROVEMENTS
Abstract
The present disclosure provides methods of improving dewatering
in the papermaking process by incorporation of functionalized
cellulose fibers in the paper furnish. Additionally, the disclosure
provides the means to eliminate process problems mainly plugging
problems in a nano/micro-fibrillated cellulose production process
by incorporation of functionalized cellulose fibers in a cellulose
fiber composition and methods of functionalizing cellulose fibers
in a paper making process. The methods according to the present
disclosure provide several advantages, such as improving the
freeness and dewatering of the paper making process during the
paper making process, leading to an increased production rate and
reduced energy consumption.
Inventors: |
HAKOVIRTA; Marko; (Opelika,
AL) ; ASHURST; William R.; (Auburn, AL) ;
AKSOY; Burak; (Auburn, AL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AUBURN UNIVERSITY |
Auburn |
AL |
US |
|
|
Family ID: |
51581368 |
Appl. No.: |
14/775158 |
Filed: |
March 14, 2014 |
PCT Filed: |
March 14, 2014 |
PCT NO: |
PCT/US14/28398 |
371 Date: |
September 11, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61783669 |
Mar 14, 2013 |
|
|
|
Current U.S.
Class: |
162/146 |
Current CPC
Class: |
D21H 21/16 20130101;
D21H 17/13 20130101; C07F 7/1804 20130101; D21H 21/10 20130101;
D21H 11/20 20130101; D21H 17/25 20130101 |
International
Class: |
D21H 17/13 20060101
D21H017/13; D21H 11/20 20060101 D21H011/20 |
Claims
1. A method of functionalizing cellulose fibers in a paper making
process, said method comprising the steps of: (a) obtaining a first
plurality of cellulose fibers; (b) functionalizing the first
plurality of cellulose fibers by subjecting the cellulose fibers to
a process in which all or part of the surface of one or more of the
first plurality of cellulose fibers is rendered hydrophobic; (c)
optionally combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers, wherein the second plurality
of cellulose fibers comprises non-functionalized cellulose fibers;
and (d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process.
2. The method of claim 1, wherein the combination of step (c)
results in a cellulose fiber composition comprising between 5% and
95% of functionalized cellulose fibers and between 5% and 95% of
non-functionalized cellulose fibers.
3. The method of claim 1, wherein the hydrophobic process is
performed according to a process selected from the group consisting
of a liquid phase silanization, a gas phase silanization, plasma
deposition, and an aqueous phase treatment scheme.
4. The method of claim 3, wherein the liquid phase silanization
comprises octadecyltrichlorosilane and a hexane.
5. The method of claim 1, wherein the paper making process is
associated with improved drainage.
6. The method of claim 1, wherein the paper making process is
associated with improved dewatering.
7. The method of claim 1, wherein the paper making process is
associated with improved freeness.
8. The method of claim 1, wherein the paper making process is
associated with improved water retention value (WRV).
9. A method of removing water in a paper making process, said
method comprising the steps of: (a) obtaining a first plurality of
cellulose fibers; (b) functionalizing the first plurality of
cellulose fibers by subjecting the cellulose fibers to a process in
which all or part of the surface of one or more of the first
plurality of cellulose fibers is rendered hydrophobic; (c)
optionally combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers, wherein the second plurality
of cellulose fibers comprises non-functionalized cellulose fibers;
and (d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process, wherein the inclusion of the first plurality of
cellulose fibers removes water from the paper making process.
10. The method of claim 9, wherein the combination of step (c)
results in a cellulose fiber composition comprising between 5% and
95% of functionalized cellulose fibers and between 5% and 95% of
non-functionalized cellulose fibers.
11. The method of claim 9, wherein the hydrophobic process is
performed according to a process selected from the group consisting
of a liquid phase silanization, a gas phase silanization, plasma
deposition, and an aqueous phase treatment scheme.
12. The method of claim 11, wherein the liquid phase silanization
comprises octadecyltrichlorosilane and a hexane.
13. The method of claim 9, wherein the paper making process is
associated with improved drainage.
14. The method of claim 9, wherein the paper making process is
associated with improved dewatering.
15. The method of claim 9, wherein the paper making process is
associated with improved freeness.
16. The method of claim 9, wherein the paper making process is
associated with improved water retention value (WRV).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 USC
.sctn.119(e) of U.S. Provisional Application Ser. No. 61/783,669,
filed on Mar. 14, 2013, the entire disclosure of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The invention relates to the functionalization of cellulose
fibers by a process to render all or part of their surface to be
hydrophobic. The invention includes methods for improving the
dewatering and drainage practices involved in a paper making
process, improving flow properties in papermaking
nano/micro-fibrillated cellulose production processes resulting in
improvements in energy expenditures associated with the current
process and significantly reduced plugging problems during
nano/micro-fibrillated cellulose production.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] The process of making paper requires a large amount of
energy, and nearly 80% of the required energy is consumed by paper
drying. In particular, the sizeable proportion of energy necessary
for paper drying is due to the process of drying by vaporization.
From one viewpoint, the paper manufacturing process is essentially
a very large dewatering operation through which network formation
and consolidation of fibers occur. The ease with which water is
released from furnish during the papermaking process affects both
the production rate and energy consumption.
[0004] The entire dewatering process for sheet formation is a very
complex sequence utilizing various physical phenomena. A low-solids
cellulose fiber and water suspension (typically <1% consistency)
is distributed on a permeable fabric belt in the paper machine.
This belt can move at a speed of some 2000 meters per minute and
the water drains out from the cellulosic fiber mixture by gravity
and inertia. Next, a hydrofoil is used on the other side of the
fabric opposite to the paper web being formed. This system is used
to apply a short term vacuum impulse and to move the fibers to
create drainage channels in the fiber web. Finally, perforated
suction rolls and vacuum flat-boxes can be used to improve
dewatering.
[0005] At this stage, the paper web has a solids content of about
15-25%. The next step involves a series of press nips where water
is forced from the paper sheet into the voids of the continuous
felts. After the press section, the solid content of the paper web
is about 40-55%. Finally, the paper web moves through a series of
steam heated rolls in order to vaporize most of the remaining water
and eventually the moisture drops to a level of 4-8% which is the
equilibrium moisture content of the finished paper product. All of
these process steps require a substantial amount of energy and
demand very high capital equipment investments and maintenance
costs.
[0006] The cost of removing one unit of moisture in the forming,
pressing, and drying sections of the paper making process is
related by the ratios 1:5:220, respectively. Therefore, removing as
much water as possible during the first two stages of the
dewatering process greatly reduces the steam heated dryer load and
improves papermaking economics provided that water removal is
balanced with achieving desired end use requirements for the
product produced such as formation. If water drainage could be
improved even slightly, the impact would be considerable from both
a financial and environmental perspective.
[0007] The paper industry has attempted to developed several
different approaches to improve drainage at the wet end and also
improve retention of some of the fines and fillers critical for
paper making process. Retention-drainage (R/D) additives such as
electrolytes, polymers or micro particle-polymer combinations and
are commonly used to improve the first-pass retention of fines and
fillers and drainage properties of furnish during the forming
process.
[0008] However, using current methods known in the art of wet-end
chemistry, fines become attached either to each other increasing
the effective size or to fibers with the aid of R/D additives and
can be agglomerated into larger particles. Effective surface area
of fines is significantly reduced with this treatment, and the
resulting flocs do not absorb as much water and obstruct the water
flow from the mat. Fines attached to fibers do not move through the
fiber mat to points where they would obstruct drainage channels
(choke-points). Although several R/D additives have been
investigated for their effects on the water removal on the forming
process, doing so often causes one or more disadvantages at a
subsequent step in the paper making process. For example, although
polyethylenimine (PEI) increases the gravity drainage of the
dewatering properties of newsprint furnish, vacuum drainage was
decreased.
[0009] Although positive effects of various R/D additives on water
drainage gravity-filtration of fiber suspensions have been
suggested, parallel tests carried out with application of vacuum
gave contradictory results. Rather than aiding in the dewatering,
the cationic polymers when used alone or in combination with
anionic acrylamide type retention aid resulted in substantially
wetter fiber mats following a standardized application of vacuum.
Moreover, a commonly used R/D additive, cationic polyacrylamide
(CATPAM), can influence the dewatering properties of the
papermaking furnish both positively and negatively, depending on
the specific polymer used and the other additives. Highly charged
cationic polyelectrolyte polymers are also used to reduce the
inter-fiber friction which enhances the rate at which fibers slide
past each other in the wet-end by partially covering the surface of
the fibers (patch agglomeration) thus aiding drainage.
[0010] Microparticle systems have also been found to significantly
improve the dewatering of the papermaking stock in neutral and
alkaline systems as well as high speed paper machines. Enzyme
treatment of cellulosic fibers also seem to improve the freeness of
the papermaking stock by reducing the hydrodynamic surface area of
fibers and by reducing fines content of the papermaking furnish.
However, excessive treatment of fibers with enzymes have been found
to increase the fines content of furnish, thus reducing the
dewatering ability.
[0011] Positive effects of various dewatering aid treatments on the
release of water during simple gravity-filtration of fiber
suspensions have been suggested. However, similar tests with
application of vacuum have been reported to give different results.
In addition, using CATPAM can improve dewatering in the wire, but
lesser water removal at the press section due to the formation of
persistent fiber flocs by the chemical treatments. More rapid
dewatering by gravity can be achieved due to the ability of water
to flow quickly within the large void spaces that surround fiber
flocs. Once most of the water has been removed by the application
vacuum, the same void spaces allow air to rush ineffectively
through the wet web, failing to maintain a pressure differential
across the thickness of the sheet. In addition, sheets with highly
flocculated fibers were found to require longer application heat in
the drying section to remove the remaining water in the sheet by
evaporation.
[0012] Therefore, there exists a need for new methods for improving
the paper making process and/or the nano/micro-fibrillated
cellulose production process by improving the dewatering techniques
that are currently utilized. Since the cost effectiveness of the
various physical means of dewatering far exceeds that of thermal
drying, significant energy saving can be expected if the physical
dewatering effectiveness is improved. Accordingly, the present
disclosure provides improved methods for functionalizing cellulose
fibers that exhibit desirable properties and provide related
advantages for improvement in the paper making process and/or the
nano/micro-fibrillated cellulose production process.
[0013] The methods comprising the functionalization of cellulose
fibers according to the present disclosure provide several
advantages compared to other methods known in the art. First, the
methods improve the freeness and dewatering of the paper making
process during the paper making process, leading to an increased
production rate and reduced energy consumption. Second, the methods
improve the suspension flow of the cellulosic fiber composition
during the paper making process, leading to a lower amount of
cellulosic fiber flocculation during the process.
[0014] Third, the methods improve the bulk of the resultant paper
made during the process. Fourth, the methods improve the thickness
of paper produced from a paper making process utilizing the
described methods. Finally, the methods result in better wet web
strength (runnability), ability to use of slower draining fibers,
ability to increase refining without production loss, and reduced
press load to maintain bulk.
[0015] The following numbered embodiments are contemplated and are
non-limiting:
[0016] 1. A method of functionalizing cellulose fibers in a paper
making process or a nano/micro-fibrillated cellulose production
process, said method comprising the steps of:
[0017] (a) obtaining a first plurality of cellulose fibers;
[0018] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic;
[0019] (c) optionally combining the first plurality of cellulose
fibers with a second plurality of cellulose fibers, wherein the
second plurality of cellulose fibers comprises non-functionalized
cellulose fibers; and
[0020] (d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process.
[0021] 2. A method of using functionalized cellulose fibers in a
paper making process or a nano/micro-fibrillated cellulose
production process, said method comprising the steps of:
[0022] (a) obtaining a first plurality of cellulose fibers;
[0023] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic;
[0024] (c) optionally combining the first plurality of cellulose
fibers with a second plurality of cellulose fibers, wherein the
second plurality of cellulose fibers comprises non-functionalized
cellulose fibers; and
[0025] (d) using the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process.
[0026] 3. A method of removing water in a paper making process or a
nano/micro-fibrillated cellulose production process, said method
comprising the steps of:
[0027] (a) obtaining a first plurality of cellulose fibers;
[0028] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic;
[0029] (c) optionally combining the first plurality of cellulose
fibers with a second plurality of cellulose fibers, wherein the
second plurality of cellulose fibers comprises non-functionalized
cellulose fibers; and
[0030] (d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process, wherein the inclusion of the first plurality of cellulose
fibers removes water from the paper making process or the
nano/micro-fibrillated cellulose production process.
[0031] 4. A method of improving drainage in a paper making process
or a nano/micro-fibrillated cellulose production process, said
method comprising the steps of:
[0032] (a) obtaining a first plurality of cellulose fibers;
[0033] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic;
[0034] (c) optionally combining the first plurality of cellulose
fibers with a second plurality of cellulose fibers, wherein the
second plurality of cellulose fibers comprises non-functionalized
cellulose fibers; and
[0035] (d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process,
[0036] wherein the inclusion of the first plurality of cellulose
fibers improves drainage in the paper making process or the
nano/micro-fibrillated cellulose production process.
[0037] 5. A method of improving dewatering of a cellulose fiber
composition, said method comprising the steps of:
[0038] (a) obtaining a first plurality of cellulose fibers;
[0039] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic; and
[0040] (c) combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers to form the cellulose fiber
composition, wherein the second plurality of cellulose fibers
comprises non-functionalized cellulose fibers,
[0041] wherein the inclusion of the first plurality of cellulose
fibers improves dewatering of the cellulose fiber composition.
[0042] 6. A method of preparing a cellulose fiber composition
comprising functionalized cellulose fibers, said method comprising
the steps of:
[0043] (a) obtaining a first plurality of cellulose fibers;
[0044] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic; and
[0045] (c) combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers to form the cellulose fiber
composition, wherein the second plurality of cellulose fibers
comprises non-functionalized cellulose fibers.
[0046] 7. A method of forming water channels in a cellulose fiber
composition, said method comprising the steps of:
[0047] (a) obtaining a first plurality of cellulose fibers;
[0048] (b) functionalizing the first plurality of cellulose fibers
by subjecting the cellulose fibers to a process in which all or
part of the surface of one or more of the first plurality of
cellulose fibers is rendered hydrophobic; and
[0049] (c) combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers to form the cellulose fiber
composition, wherein the second plurality of cellulose fibers
comprises non-functionalized cellulose fibers,
[0050] wherein the inclusion of the first plurality of cellulose
fibers forms water
[0051] channels in the cellulose fiber composition.
[0052] 8. The method of any one of the preceding clauses, wherein
the paper making process results in formation of paper comprising
the first plurality of cellulose fibers and optionally the second
plurality of cellulose fibers.
[0053] 9. The method of any one of the preceding clauses, wherein
the method is performed in the paper making process.
[0054] 10. The method of any one of the preceding clauses, wherein
the method is performed in the nano/micro-fibrillated cellulose
production process.
[0055] 11. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising between 5% and 95% of functionalized
cellulose fibers and between 5% and 95% of non-functionalized
cellulose fibers.
[0056] 12. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising between 10% and 90% of functionalized
cellulose fibers and between 10% and 90% of non-functionalized
cellulose fibers.
[0057] 13. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising between 15% and 85% of functionalized
cellulose fibers and between 15% and 85% of non-functionalized
cellulose fibers.
[0058] 14. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising between 25% and 75% of functionalized
cellulose fibers and between 25% and 75% of non-functionalized
cellulose fibers.
[0059] 15. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising between 35% and 65% of functionalized
cellulose fibers and between 35% and 65% of non-functionalized
cellulose fibers.
[0060] 16. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 1% of functionalized cellulose fibers
and about 99% of non-functionalized cellulose fibers.
[0061] 17. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 5% of functionalized cellulose fibers
and about 95% of non-functionalized cellulose fibers.
[0062] 18. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 10% of functionalized cellulose fibers
and about 90% of non-functionalized cellulose fibers.
[0063] 19. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 15% of functionalized cellulose fibers
and about 85% of non-functionalized cellulose fibers.
[0064] 20. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 25% of functionalized cellulose fibers
and about 75% of non-functionalized cellulose fibers.
[0065] 21. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 35% of functionalized cellulose fibers
and about 65% of non-functionalized cellulose fibers.
[0066] 22. The method of any one of the preceding clauses, wherein
the combination of step (c) results in a cellulose fiber
composition comprising about 50% of functionalized cellulose fibers
and about 50% of non-functionalized cellulose fibers.
[0067] 23. The method of any one of the preceding clauses, wherein
the first plurality of cellulose fibers is pre-treated prior to
functionalizing.
[0068] 24. The method of any one of the preceding clauses, wherein
the second plurality of cellulose fibers is pre-treated.
[0069] 25. The method of any one of the preceding clauses, wherein
the pre-treatment is a mechanical method that reduces fiber size of
the first or second plurality of cellulose fibers.
[0070] 26. The method of any one of the preceding clauses, wherein
the pre-treatment is a enzymatic method that reduces fiber size of
the first or second plurality of cellulose fibers.
[0071] 27. The method of any one of the preceding clauses, wherein
the pre-treatment is selected from the group consisting of beating,
refining, cyrocrushing, grinding, electrospinning, and enzymatic
pretreatment.
[0072] 28. The method of any one of the preceding clauses, wherein
the pre-treatment is beating.
[0073] 29. The method of any one of the preceding clauses, wherein
the pre-treatment is refining.
[0074] 30. The method of any one of the preceding clauses, wherein
the pre-treatment is cyrocrushing.
[0075] 31. The method of any one of the preceding clauses, wherein
the pre-treatment is grinding.
[0076] 32. The method of any one of the preceding clauses, wherein
the pre-treatment is electrospinning.
[0077] 33. The method of any one of the preceding clauses, wherein
the pre-treatment is enzymatic pretreatment.
[0078] 34. The method of any one of the preceding clauses, wherein
the cellulose fibers comprise hardwood cellulose fibers.
[0079] 35. The method of any one of the preceding clauses, wherein
the cellulose fibers comprise softwood cellulose fibers.
[0080] 36. The method of any one of the preceding clauses, wherein
the cellulose fibers comprise plant fibers.
[0081] 37. The method of any one of the preceding clauses, wherein
the cellulose fibers are bamboo fibers.
[0082] 38. The method of any one of the preceding clauses, wherein
the cellulose fibers are kenaf fibers.
[0083] 39. The method of any one of the preceding clauses, wherein
the cellulose fibers are reed fibers.
[0084] 40. The method of any one of the preceding clauses, wherein
the paper is selected from the group consisting of board,
paperboard, fiberboard, cardboard, a printing paper grade, tissue
paper, towel paper, a sanitary paper grade, a personal care paper
grade, a superabsorbent paper grade, or any combination
thereof.
[0085] 41. The method of any one of the preceding clauses, wherein
the paper is board.
[0086] 42. The method of any one of the preceding clauses, wherein
the paper is paperboard.
[0087] 43. The method of any one of the preceding clauses, wherein
the paper is fiberboard.
[0088] 44. The method of any one of the preceding clauses, wherein
the paper is cardboard.
[0089] 45. The method of any one of the preceding clauses, wherein
the paper is a printing paper grade.
[0090] 46. The method of any one of the preceding clauses, wherein
the paper is tissue paper.
[0091] 47. The method of any one of the preceding clauses, wherein
the paper is towel paper.
[0092] 48. The method of any one of the preceding clauses, wherein
the paper is a sanitary paper grade.
[0093] 49. The method of any one of the preceding clauses, wherein
the paper is a personal care paper grade.
[0094] 50. The method of any one of the preceding clauses, wherein
the paper is a superabsorbent paper grade.
[0095] 51. The method of any one of the preceding clauses, wherein
the hydrophobic process is performed according to a process
selected from the group consisting of a liquid phase silanization,
a gas phase silanization, plasma deposition, and an aqueous phase
treatment scheme.
[0096] 52. The method of any one of the preceding clauses, wherein
the hydrophobic process comprises a liquid phase silanization.
[0097] 53. The method of any one of the preceding clauses, wherein
the hydrophobic process comprises a gas phase silanization.
[0098] 54. The method of any one of the preceding clauses, wherein
the hydrophobic process comprises plasma deposition.
[0099] 55. The method of any one of the preceding clauses, wherein
the hydrophobic process comprises an aqueous phase treatment
scheme.
[0100] 56. The method of any one of the preceding clauses, wherein
the liquid phase silanization scheme comprises treating the
cellulose fibers with an organosilane.
[0101] 57. The method of any one of the preceding clauses, wherein
the organosilane is octadecyltrichlorosilane.
[0102] 58. The method of any one of the preceding clauses, wherein
the liquid phase silanization scheme comprises treating the
cellulose fibers with a fluorosilane.
[0103] 59. The method of any one of the preceding clauses, wherein
the liquid phase silanization scheme comprises treating the
cellulose fibers with a composition comprises a silane dissolved in
a solvent.
[0104] 60. The method of any one of the preceding clauses, wherein
the solvent is a hexane.
[0105] 61. The method of any one of the preceding clauses, wherein
the liquid phase silanization comprises octadecyltrichlorosilane
and a hexane.
[0106] 62. The method of any one of the preceding clauses, wherein
the paper making process or the nano/micro-fibrillated cellulose
production process is associated with improved drainage.
[0107] 63. The method of any one of the preceding clauses, wherein
the drainage is improved compared to a paper making process or a
nano/micro-fibrillated cellulose production process without
functionalized cellulose fibers.
[0108] 64. The method of any one of the preceding clauses, wherein
the paper making process or the nano/micro-fibrillated cellulose
production process is associated with improved dewatering.
[0109] 65. The method of any one of the preceding clauses, wherein
the dewatering is improved compared to a paper making process or a
nano/micro-fibrillated cellulose production process without
functionalized cellulose fibers.
[0110] 66. The method of any one of the preceding clauses, wherein
the paper making process or the nano/micro-fibrillated cellulose
production process is associated with improved freeness.
[0111] 67. The method of any one of the preceding clauses, wherein
the freeness is improved compared to a paper making process or a
nano/micro-fibrillated cellulose production process without
functionalized cellulose fibers.
[0112] 68. The method of any one of the preceding clauses, wherein
the paper making process or the nano/micro-fibrillated cellulose
production process is associated with improved water retention
value (WRV).
[0113] 69. The method of any one of the preceding clauses, wherein
the WRV is improved compared to a paper making process or a
nano/micro-fibrillated cellulose production process without
functionalized cellulose fibers.
[0114] 70. The method of any one of the preceding clauses, wherein
the paper making process or the nano/micro-fibrillated cellulose
production process is associated with improved suspension flow.
[0115] 71. The method of any one of the preceding clauses, wherein
the improved suspension flow is characterized by a lower amount of
cellulosic fiber flocculation.
[0116] 72. The method of any one of the preceding clauses, wherein
the suspension flow properties are improved compared to a paper
making process or a nano/micro-fibrillated cellulose production
process without functionalized cellulose fibers.
[0117] 73. The method of any one of the preceding clauses, wherein
the improved suspension flow is characterized by a lower amount of
cellulosic fiber flocculation.
[0118] 74. The method of any one of the preceding clauses, wherein
the paper making process or the nano/micro-fibrillated cellulose
production process is associated with improved bulk.
[0119] 75. The method of any one of the preceding clauses, wherein
the bulk is improved compared to a paper making process or a
nano/micro-fibrillated cellulose production process without
functionalized cellulose fibers.
[0120] 76. The method of any one of the preceding clauses, wherein
the paper making process produces paper with increased
thickness.
[0121] 77. The method of any one of the preceding clauses, wherein
the thickness is increased compared to paper produced from a paper
making process without functionalized cellulose fibers.
[0122] 78. The method of any one of the preceding clauses, wherein
the paper comprises an additional component or additive.
[0123] 79. The method of any one of the preceding clauses, wherein
the additional component or additive is functionalized.
[0124] 80. The method of any one of the preceding clauses, wherein
the additional component is selected from the group consisting of
diatoms, diatomaceous earth, and porous nanosilica.
[0125] 81. The method of any one of the preceding clauses, wherein
the additional component is functionalized before its addition to
the paper.
[0126] 82. The method of any one of the preceding clauses, wherein
the additional component is functionalized after its addition to
the paper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0127] FIG. 1 shows examples of the physical changes of fibers
after valley beater pre-treatment.
[0128] FIG. 2 shows Canadian Standard Freeness (CSF) values of
bleached hardwood pulp mixtures at varying amounts of
functionalized fiber addition. Pre-treatment included Valley
beating until CSF value 530 ml.
[0129] FIG. 3 shows CSF values of bleached softwood pulp mixtures
at varying amounts of functionalized fiber addition. Pre-treatment
included Valley beating until CSF value 530 ml.
[0130] FIG. 4 shows Water Retention Value (WRV) of bleached
hardwood pulp mixtures at varying amounts of functionalized fiber
addition. Pre-treatment included Valley beating until CSF value 530
ml.
[0131] FIG. 5 shows WRV values of bleached softwood pulp mixtures
at varying amounts of functionalized fiber addition. Pre-treatment
included Valley beating until CSF value 530 ml.
[0132] FIG. 6 shows sedimentation properties of non-functionalized
and functionalized hardwood fibers: (a) non-functionalized
hardwood, 1 minute (left 530 ml CSF, right 660 ml CSF), (b)
functionalized hardwood, 1 minute (left 530 ml CSF, right 660 ml
CSF).
[0133] FIG. 7 shows sedimentation properties of non-functionalized
and 100% functionalized hardwood fibers: (a) non-functionalized
hardwood, 60 minutes (left 530 ml CSF, right 660 ml CSF), (b) 100%
functionalized hardwood, 60 minutes (left 530 ml CSF, right 660 ml
CSF).
[0134] FIG. 8 shows sediment volumes of 100% functionalized
(.diamond-solid.) and non-functionalized (.box-solid.) hardwood
fibers of 530 ml CSF.
[0135] FIG. 9 shows sediment volumes of 100% functionalized
(.diamond-solid.) and non-functionalized (.box-solid.) hardwood
fibers of 660 ml CSF (not pre-treated).
[0136] Various embodiments of the invention are described herein as
follows. In one embodiment described herein, method of
functionalizing cellulose fibers in a paper making process or a
nano/micro-fibrillated cellulose production process is provided.
The method comprises the steps of a) obtaining a first plurality of
cellulose fibers; b) functionalizing the first plurality of
cellulose fibers by subjecting the cellulose fibers to a process in
which all or part of the surface of one or more of the first
plurality of cellulose fibers is rendered hydrophobic; c)
optionally combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers, wherein the second plurality
of cellulose fibers comprises non-functionalized cellulose fibers;
and d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process.
[0137] In another embodiment described herein, a method of using
functionalized cellulose fibers in a paper making process or a
nano/micro-fibrillated cellulose production process is provided.
The method comprises the steps of a) obtaining a first plurality of
cellulose fibers; b) functionalizing the first plurality of
cellulose fibers by subjecting the cellulose fibers to a process in
which all or part of the surface of one or more of the first
plurality of cellulose fibers is rendered hydrophobic; c)
optionally combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers, wherein the second plurality
of cellulose fibers comprises non-functionalized cellulose fibers;
and d) using the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process.
[0138] In yet another embodiment described herein, a method of
removing water in a paper making process or a
nano/micro-fibrillated cellulose production process is provided.
The method comprises the steps of a) obtaining a first plurality of
cellulose fibers; b) functionalizing the first plurality of
cellulose fibers by subjecting the cellulose fibers to a process in
which all or part of the surface of one or more of the first
plurality of cellulose fibers is rendered hydrophobic; c)
optionally combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers, wherein the second plurality
of cellulose fibers comprises non-functionalized cellulose fibers;
and d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process, wherein the inclusion of the first plurality of cellulose
fibers removes water from the paper making process or the
nano/micro-fibrillated cellulose production process.
[0139] In another embodiment described herein, a method of
improving drainage in a paper making process or a
nano/micro-fibrillated cellulose production process is provided.
The method comprises the steps of a) obtaining a first plurality of
cellulose fibers; b) functionalizing the first plurality of
cellulose fibers by subjecting the cellulose fibers to a process in
which all or part of the surface of one or more of the first
plurality of cellulose fibers is rendered hydrophobic; c)
optionally combining the first plurality of cellulose fibers with a
second plurality of cellulose fibers, wherein the second plurality
of cellulose fibers comprises non-functionalized cellulose fibers;
and d) utilizing the first plurality of cellulose fibers, and
optionally the second plurality of cellulose fibers, in the paper
making process or the nano/micro-fibrillated cellulose production
process, wherein the inclusion of the first plurality of cellulose
fibers improves drainage in the paper making process or the
nano/micro-fibrillated cellulose production process.
[0140] In yet another embodiment described herein, a method of
improving dewatering of a cellulose fiber composition is provided.
The method comprises the steps of a) obtaining a first plurality of
cellulose fibers; b) functionalizing the first plurality of
cellulose fibers by subjecting the cellulose fibers to a process in
which all or part of the surface of one or more of the first
plurality of cellulose fibers is rendered hydrophobic; and c)
combining the first plurality of cellulose fibers with a second
plurality of cellulose fibers to form the cellulose fiber
composition, wherein the second plurality of cellulose fibers
comprises non-functionalized cellulose fibers, wherein the
inclusion of the first plurality of cellulose fibers improves
dewatering of the cellulose fiber composition.
[0141] In another embodiment described herein, a method of
preparing a cellulose fiber composition comprising functionalized
cellulose fibers is provided. The method comprises the steps of a)
obtaining a first plurality of cellulose fibers; b) functionalizing
the first plurality of cellulose fibers by subjecting the cellulose
fibers to a process in which all or part of the surface of one or
more of the first plurality of cellulose fibers is rendered
hydrophobic; and c) combining the first plurality of cellulose
fibers with a second plurality of cellulose fibers to form the
cellulose fiber composition, wherein the second plurality of
cellulose fibers comprises non-functionalized cellulose fibers.
[0142] In yet another embodiment described herein, a method of
forming water channels in a cellulose fiber composition is
provided. The method comprises the steps of a) obtaining a first
plurality of cellulose fibers; b) functionalizing the first
plurality of cellulose fibers by subjecting the cellulose fibers to
a process in which all or part of the surface of one or more of the
first plurality of cellulose fibers is rendered hydrophobic; and c)
combining the first plurality of cellulose fibers with a second
plurality of cellulose fibers to form the cellulose fiber
composition, wherein the second plurality of cellulose fibers
comprises non-functionalized cellulose fibers, wherein the
inclusion of the first plurality of cellulose fibers forms water
channels in the cellulose fiber composition.
[0143] In the various embodiments, the method involves cellulose
fibers in a paper making process or a nano/micro-fibrillated
cellulose production process. As used herein, the term "cellulose
fibers" refers to fibers from a plant or plant-based materials,
including natural cellulose fibers, manufactured cellulose fibers,
and the like. As used herein, the term "paper making process"
refers to the manufacture of paper. The paper making process is
well known in the art such as, for example, as described in Holik,
Handbook of Paper and Board, Wiley-VCH, Second Edition (2013). As
used herein, the term "nano/micro-fibrillated cellulose production
process" is also well known in the art.
[0144] In the present disclosure, the functionalization of
cellulose fibers is described. As used herein, the term
"functionalization" refers to the utilization of any process that
renders all or part of the surface of at least one cellulose fiber
hydrophobic. The term "hydrophobic" has its general definition as
known in the art, i.e. the physical property of a molecule that is
repelled from, tends not to combine with, or is incapable of
dissolving in water.
[0145] In some aspects, the paper making process results in the
formation of paper comprising the first plurality of cellulose
fibers and optionally the second plurality of cellulose fibers.
[0146] In various aspects, a first plurality of cellulose fibers is
combined with a second plurality of cellulose fibers. In some
embodiments, the combination results in a cellulose fiber
composition comprising between 5% and 95% of functionalized
cellulose fibers and between 5% and 95% of non-functionalized
cellulose fibers. In other embodiments, the combination results in
a cellulose fiber composition comprising between 10% and 90% of
functionalized cellulose fibers and between 10% and 90% of
non-functionalized cellulose fibers. In yet other embodiments, the
combination of results in a cellulose fiber composition comprising
between 15% and 85% of functionalized cellulose fibers and between
15% and 85% of non-functionalized cellulose fibers. In some
embodiments, the combination results in a cellulose fiber
composition comprising between 25% and 75% of functionalized
cellulose fibers and between 25% and 75% of non-functionalized
cellulose fibers. In other embodiments, the combination results in
a cellulose fiber composition comprising between 35% and 65% of
functionalized cellulose fibers and between 35% and 65% of
non-functionalized cellulose fibers.
[0147] In some embodiments, the combination results in a cellulose
fiber composition comprising about 1% of functionalized cellulose
fibers and about 99% of non-functionalized cellulose fibers. In
other embodiments, the combination results in a cellulose fiber
composition comprising about 5% of functionalized cellulose fibers
and about 95% of non-functionalized cellulose fibers. In yet other
embodiments, the combination results in a cellulose fiber
composition comprising about 10% of functionalized cellulose fibers
and about 90% of non-functionalized cellulose fibers. In some
embodiments, the combination results in a cellulose fiber
composition comprising about 15% of functionalized cellulose fibers
and about 85% of non-functionalized cellulose fibers. In other
embodiments, the combination results in a cellulose fiber
composition comprising about 25% of functionalized cellulose fibers
and about 75% of non-functionalized cellulose fibers. In yet other
embodiments, the combination results in a cellulose fiber
composition comprising about 35% of functionalized cellulose fibers
and about 65% of non-functionalized cellulose fibers. In some
embodiments, the combination results in a cellulose fiber
composition comprising about 50% of functionalized cellulose fibers
and about 50% of non-functionalized cellulose fibers.
[0148] In various aspects, the first plurality of cellulose fibers
is pre-treated prior to functionalizing. In other aspects, the
second plurality of cellulose fibers is pre-treated. As used
herein, the term "pre-treatment" refers to any method that reduces
fiber size of the first plurality of cellulose fibers or the second
plurality of cellulose fibers. The pre-treatment can be performed
according to any procedure or process known in the art. In some
embodiments, the pre-treatment is a mechanical method that reduces
fiber size of the first or second plurality of cellulose fibers. In
some embodiments, the pre-treatment is an enzymatic method that
reduces fiber size of the first or second plurality of cellulose
fibers. In other embodiments, the pre-treatment is selected from
the group consisting of beating, refining, cyrocrushing, grinding,
electrospinning, and enzymatic pretreatment. In one embodiment, the
pre-treatment is beating, for example via a Valley beater. In other
embodiments, the pre-treatment is refining. In yet other
embodiments, the pre-treatment is cyrocrushing. In some
embodiments, the pre-treatment is grinding. In other embodiments,
the pre-treatment is electrospinning. In yet other embodiments, the
pre-treatment is enzymatic pretreatment.
[0149] Any type of cellulose fibers can be utilized according to
the present disclosure. In some embodiments, the cellulose fibers
comprise hardwood cellulose fibers. In other embodiments, the
cellulose fibers comprise softwood cellulose fibers. The terms
"hardwood" and "softwood" are well known in the art and are given
their understood meanings. In yet other embodiments, the cellulose
fibers comprise plant fibers. In some embodiments, the cellulose
fibers are bamboo fibers. In other embodiments, the cellulose
fibers are kenaf fibers. In yet other embodiments, the cellulose
fibers are reed fibers.
[0150] The "paper" of the paper making process, or the resultant
paper made from the paper making process, includes all types of
paper that can be made according to the processes known in the art.
For example, in various aspects, paper is selected from the group
consisting of board, paperboard, fiberboard, cardboard, a printing
paper grade, tissue paper, towel paper, a sanitary paper grade, a
personal care paper grade, a superabsorbent paper grade, or any
combination thereof. In some embodiments, the paper is board. In
other embodiments, the paper is paperboard. In yet other
embodiments, the paper is fiberboard. In some embodiments, the
paper is cardboard. In other embodiments, the paper is a printing
paper grade. In yet other embodiments, the paper is tissue paper.
In some embodiments, the paper is towel paper. In other
embodiments, the paper is a sanitary paper grade. In yet other
embodiments, the paper is a personal care paper grade, such as
diapers, feminine hygiene products, fluff paper grades, and the
like. In some embodiments, the paper is a superabsorbent paper
grade.
[0151] In the present disclosure, cellulose fibers may be
functionalized according to any process that renders all or part of
the surface of at least one cellulose fiber hydrophobic. In some
aspects, the hydrophobic process is performed according to a
process selected from the group consisting of a liquid phase
silanization, a gas phase silanization, plasma deposition, and an
aqueous phase treatment scheme. Methods of rendering cellulose
fibers to be hydrophobic are well known in the art. In some
aspects, the hydrophobic process comprises a liquid phase
silanization. In other embodiments, the hydrophobic process
comprises a gas phase silanization. In yet other embodiments, the
hydrophobic process comprises plasma deposition. In some
embodiments, the hydrophobic process comprises an aqueous phase
treatment scheme.
[0152] In various aspects, the liquid phase silanization scheme
comprises treating the cellulose fibers with an organosilane. In
certain aspects, the organosilane is octadecyltrichlorosilane. In
other aspects, the liquid phase silanization scheme comprises
treating the cellulose fibers with a fluorosilane. In yet other
aspects, the liquid phase silanization scheme comprises treating
the cellulose fibers with a composition comprises a silane
dissolved in a solvent. In some embodiments, the solvent is a
hexane. In one embodiment, the liquid phase silanization comprises
octadecyltrichlorosilane and a hexane.
[0153] In some embodiments, the paper making process or the
nano/micro-fibrillated cellulose production process is associated
with improved drainage. The concept of drainage is well known in
the art of paper making and nano/micro-fibrillated cellulose
production. For example, "freeness" is standard measure of how
quickly water is able to drain from a fiber furnish sample in the
paper making process. In certain aspects, the drainage is improved
compared to a paper making process or a nano/micro-fibrillated
cellulose production process without functionalized cellulose
fibers.
[0154] In some embodiments, the paper making process or the
nano/micro-fibrillated cellulose production process is associated
with improved dewatering. The concept of dewatering is well known
in the art of paper making and is associated with any means that
reduces the water used during the paper making process. In certain
aspects, the dewatering is improved compared to a paper making
process or a nano/micro-fibrillated cellulose production process
without functionalized cellulose fibers.
[0155] In some embodiments, the paper making process or the
nano/micro-fibrillated cellulose production process is associated
with improved freeness. For example, freeness can be measured
utilizing the Canadian Standard Freeness (CSF) method. In certain
aspects, the freeness is improved compared to a paper making
process or a nano/micro-fibrillated cellulose production process
without functionalized cellulose fibers.
[0156] In some embodiments, the paper making process or the
nano/micro-fibrillated cellulose production process is associated
with improved water retention value. Water Retention Value (WRV) is
a useful tool in evaluating the performance of pulps relative to
dewatering behavior on the paper machine. The WRV method was
established to provide standard values of centrifugal force, time
of centrifuging, and sample preparation so that results can be
compared between investigators at standard values. The WRV test can
be used to estimate the maximum amount of water that can be removed
from a certain furnish before the wet web leaves the press section
of a paper machine. Examples of WRV measurements are described
herein. In certain aspects, the WRV is improved compared to a paper
making process or a nano/micro-fibrillated cellulose production
process without functionalized cellulose fibers.
[0157] In some embodiments, the paper making process or the
nano/micro-fibrillated cellulose production process is associated
with improved suspension flow. The concept of suspension flow is
well known in the art of paper making and nano/micro-fibrillated
cellulose production, for example characterized by an observation
of significantly fewer process problems such as plugging of the
microfluidizer channels. In various aspects, the improved
suspension flow is characterized by a lower amount of cellulosic
fiber flocculation. As used herein, the term "flocculation" refers
to a process of contact and adhesion whereby the particles of a
dispersion form larger-size clusters. In certain aspects, the
suspension flow properties are improved compared to a paper making
process or a nano/micro-fibrillated cellulose production process
without functionalized cellulose fibers. In certain aspects, the
nano/micro-fibrillated cellulose production can utilize fiber
samples prepared using a microfluidizer. After, the cellulose fiber
composition is passed through the channels of the microfluidizer,
the system can be evaluated to determine the presence or absence of
plugging problems of the chambers of the microfluidizer.
Advantageously, the nano/micro-fibrillated cellulose production
utilizing the methods of the present disclosure are substantially
free of problems that are typically observed in the traditional
production of nanofibrillated cellulose (e.g., minimal plugging of
the chambers is observed using the methods of the present
disclosure).
[0158] In some embodiments, the paper making process or the
nano/micro-fibrillated cellulose production process is associated
with improved bulk. Paper bulk is well known in the art and is
defined as the volume occupied by a given mass of paper (i.e., the
inverse of density). The bulk of paper and paperboard is important
because it contributes to the paper's thickness, also known as
caliper. Increased paper thickness leads to higher rigidity or
bending stiffness, an important measure of strength. Higher bulk
also allows the papermaker to calendar the paper under greater
pressure, which is done by passing it through rollers. In various
aspects, the bulk is improved compared to a paper making process or
a nano/micro-fibrillated cellulose production process without
functionalized cellulose fibers.
[0159] In some embodiments, the paper making process produces paper
with increased thickness. Increased paper thickness leads to higher
rigidity or bending stiffness, an important measure of strength. In
various aspects, the thickness is increased compared to paper
produced from a paper making process without functionalized
cellulose fibers.
[0160] In certain aspects of the present disclosure, a method of
forming water channels in a cellulose fiber composition is
provided. As used herein, the term "water channels" refers to any
channel in the formed cellulose fiber composition through which
water may pass, such as a channel in a mat.
[0161] In various aspects, other paper components or additives can
be functionalized according to the methods described herein. In
certain embodiments, components such diatoms, diatomaceous earth,
other forms of porous nanosilica, and the like could be added to
the paper matrix. These component could be functionalized according
to the described methods either before or after their addition to
the paper.
[0162] While the invention is susceptible to various modifications
and alternative forms, specific embodiments are herein described in
detail. It should be understood, however, that there is no intent
to limit the invention to the particular forms described, but on
the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the scope of the
invention.
EXAMPLE 1
Pre-Treatment of Cellulose Fibers
[0163] Cellulose fibers can undergo pre-treatment prior to
functionalization. In this example, bleached hardwood kraft and
bleached softwood kraft pulps underwent pre-treatment by beating.
The beating pre-treatment was performed by using a laboratory size
Valley beater. The fibers were beaten until a pre-determined
freeness testing value (530 ml) was reached. In general, beating
causes fibers to flatten, shorten and internally and externally
fibrillate. As shown in FIG. 1, cellulose fibers undergo physical
changes following pre-treatment.
[0164] After the pre-determined step, fiber mats were prepared from
the beaten pulps by using Buchner funnel and filter paper. They
were then allowed to air dry at ambient conditions.
EXAMPLE 2
Functionalization of Cellulose Fibers
[0165] Air dried fiber mats comprising cellulose fibers can be
subjected to a process in which all or part of the surface of the
cellulose fibers is rendered hydrophobic. For example, the
cellulose fibers can be treated using a liquid phase silanization
scheme. In this example, cellulose fibers were treated with
octadecyltrichlorosilane (OTS) dissolved in one or more
hexanes.
[0166] The functionalization process that results in the bonding of
the OTS molecule to the cellulose surface can involve two
reactions: 1) the hydrolysis of OTS with adventitious dissolved
water to produce the reactive intermediate (a trisolanol) and 2)
the condensation of the trisilanol with surface hydroxyl groups to
form a grafted OTS moiety. The batch process begins with the
preparation and conditioning of 2 liters of an OTS-hexane solution.
This solution is allowed to condition by uptake of ambient humidity
for approximately 10 minutes to cause the hydrolysis step of the
functionalization mechanism.
[0167] Cellulose fibers as well as a rigorously cleaned piece of
silicon (100) wafer are added to the solution and the mixture is
allowed to react for a period of time. Periodically, the silicon
(100) wafer piece is removed from the solution and checked for
completeness of functionalization by contact angle goniometry. Once
the water contact angle on the silicon (100) piece exceeds
105.degree., the functionalization is deemed to be complete. The
functionalized fibers are separated from the spent OTS-hexane
solution by Buchner funnel filtration and rinsing with neat hexane.
The fibers are dried to bone-dryness in an oven at 77.degree. C.
prior to testing. The concentration of OTS in the OTS-hexane
solution is determined based on an assumed specific surface area of
cellulose fiber (100 m.sup.2/g) and complete surface coverage by
functionalization.
[0168] For the system under present study, this amount was
approximately 1.7 mmol OTS per air-dried gram of cellulose fiber to
be treated. The amount of cellulose to be treated is weighed, and
the appropriate amount of neat OTS is added to the 2 liters of
hexane to prepare the OTS-hexane solution. A typical amount of
cellulose fibers treated according to this example is 50 grams.
EXAMPLE 3
Freeness Measurements of Functionalized Cellulose Fiber
Compositions
[0169] Freeness is an industry-standard measure of how quickly
water is able to drain from a fiber furnish sample. In many cases,
there is a direct correlation between freeness value and either 1)
a target level of refining of pulp, or 2) the ease of drainage of
white water from the wet web, especially in the early sections of a
Fourdrinier former. Freeness of pulp (Canadian standard method) was
measured according to T227 OM-09 (Tappi Stadards).
[0170] In this example, Canadian Standard Freeness (CSF) values
were obtained for bleached hardwood and softwood pulp mixtures
containing various percentage of functionalized fibers. FIG. 2
shows CSF values observed for bleached hardwood pulp mixtures. FIG.
3 shows CSF values observed for bleached softwood pulp
mixtures.
[0171] As demonstrated in FIGS. 2 and 3, the addition of
functionalized fibers into the furnish mixture where no
pre-treatment was applied to the fibers had a limited effect on the
CSF values. However, this effect was less prevalent at the mixture
percentages of 25% and lower of functionalized fiber content.
Pre-treating the pulp samples by beating prior to functionalization
and adding functionalized fibers into pre-treated pulp drastically
improves the CSF values of the pulp, resulting in increasing the
freeness of the pulp mixtures.
[0172] When pulp was pre-treated using a valley beater to reach 530
CSF, the highest increase in the CSF values was observed.
Pre-treating pulp with a valley beater typically shortens the
fibers and increases fibrillation. For both hardwood and softwood
pulp types, the increased percentages of the functionalized fibers
in the furnish mixture increased the CSF value considerably
(increased to 43% for hardwood and increased to 38% for softwood).
It was found that even a 5% addition of functionalized fiber into
the fiber furnish increased the CSF values between 10 and 15 ml for
both hardwood and softwood at both pre-treatment levels. Detailed
data set from the CSF measurements can be found in Tables 1 and 2,
which show a comparison of fibers before pre-treatment by beating
with a Valley beater and after pre-treatment for hardwood fibers
and for softwood fibers, respectively.
TABLE-US-00001 TABLE 1 CSF values for hardwood cellulose fibers
before pre-treatment and after pre-treatment Hardwood No
Pre-treatment Pre-treatment Fiber Mixtures (%) (CSF (ml)) (CSF
(ml)) 100% Non-Functionalized (NF) 720 530 100% Functionalized (F)
750 760 50% NF/50% F 750 660 75% NF/25% F 730 600 90% NF/10% F 730
550 95% NF/5% F 730 540
TABLE-US-00002 TABLE 2 CSF values for softwood cellulose fibers
before pre-treatment and after pre-treatment No Pre-treatment
Pre-treatment Fiber Mixtures (%) (CSF (ml)) (CSF (ml)) 100%
Non-Functionalized (NF) 660 530 100% Functionalized (F) 730 730 50%
NF/50% F 710 670 75% NF/25% F 680 650 90% NF/10% F 670 620 95%
NF/5% F 670 605
[0173] Taking into account the repeatability of the CSF value tests
after the pre-treatment, both hardwood and softwood pulps behaved
similarly. However, there is a slight CSF difference in the lower
functionalized percentage of fibers comparing the pre-treated
hardwood and softwood pulps. Before pre-treatment, the softwood
fibers were approximately 2.5 mm long and about 70 .mu.m wide and
hardwood fibers before pre-treatment were approximately about 3 mm
in length and 40 .mu.m in width. Based on the observed results, it
is clear that the CSF value correlates to the physical properties
and dimensions of the fiber (combined effect of diameter, length
and level of fibrillation). Even though after the pre-treatment of
both pulp types the CSF value was the same, the difference of the
tail of the curve between hardwood and softwood point out that the
fiber dimensions and the level of fibrillation are different in
both pulp types (see FIGS. 2 and 3, respectively).
[0174] The hydrophobic fibers that have less surface area or less
external reach due to fibrillation do appear to create less
drainage improving effect in the pulp. Due to the hydrophobic
nature surrounding the treated fibers reduction of the inter-fiber
friction, additional fiber movement in furnish, and in general
reorientation of fibers may be expected. This activity would be
anticipated to aid gravity drainage of fiber suspension.
Furthermore, this may be indirect evidence that the phenomenology
of the drainage improvement is very similar to the highly charged
cationic polyelectrolyte polymers that are used in reducing the
inter-fiber friction in the wet-end.
EXAMPLE 4
Water Retention Value (WRV) Measurements of Functionalized
Cellulose Fiber Compositions
[0175] Water Retention Value (WRV) is a useful tool in evaluating
the performance of pulps relative to dewatering behavior on the
paper machine. The WRV method was established to provide standard
values of centrifugal force, time of centrifuging, and sample
preparation so that results can be compared between investigators
at standard values. The WRV test can be used to estimate the
maximum amount of water that can be removed from a certain furnish
before the wet web leaves the press section of a paper machine.
[0176] The basic WRV measurement procedure was the following: the
wet specimen weight (W5) is obtained by subtracting the weight of
the filtering crucible or specimen holder alone (W1) from the
weight of the specimen and holder after centrifuging (W2). The dry
specimen weight (W3) is measured by subtracting the weight of the
filtering crucible or specimen holder alone (W1) from the weight of
the specimen and holder after drying (W4). Finally the water
retention value is reported to three significant figures, as the
ratio of grams of water to grams of fiber after centrifuging
according the following equation:
WRV=(W2-W4)/(W4-W1)=(W5-W3)/W3.
[0177] WRV testing was done also using Valley beating as the
pre-treatment. The starting CSF values for both hardwood and
softwood were about 530 ml. Since the pulp mixtures with no
pre-treatment had limited effect on freeness values WRV tests were
not performed on the pulp mixtures with no pre-treatment. In both
CSF and WRV testing, it was determined that reaching exactly the
same CSF value from pre-treatment was difficult and therefore an
error of about 2-3% was observed. However, this was not expected to
create uncertainties as the overall repeatability relatively to the
starting CSF value has been reported to be 3-5% with CSF of 530
ml.
[0178] WRV is a standardized empirical measure of the capacity of a
test pad of fibers to hold and retain water. It is well known that
WRV-value increases upon the increase in beating with a Valley
beater because it causes flattening of fibers, partial removal of
primary wall, and loosening of internal structure. This promotes
fiber swelling and renders fibers soft and flexible. The swelling
phenomenon occurs concurrently with the development of external
fibrils that involves loosening of the fibrils and rising of the
finer microfibrils on the surfaces of the fibers which results in a
very large increase in surface area on the fibers. As a result,
beaten fibers effectively hold water. In the paper making process,
the WRV value of papermaking furnishes is known to increase with
increasing refining and increasing pH. Higher pH values promote
fiber swelling and water access to swollen fibers is considerably
easier. Also, WRV value tends to decrease when kraft fibers are
dried and re-slurried due to increased stiffness of the fibers.
[0179] FIGS. 4 and 5 show the correlation of fiber
functionalization to WRV for hardwood pulp and softwood pulp,
respectively. Furthermore, detailed results are presented in Tables
3 and 4 for hardwood pulp and softwood pulp, respectively.
TABLE-US-00003 TABLE 3 WRV values for hardwood cellulose fibers
following pre-treatment Hardwood Pre-treatment Fiber Mixtures (%)
(WRV (g/g)) 100% Non-Functionalized (NF) 2.25 100% Functionalized
(F) 1.37 50% NF/50% F 1.42 75% NF/25% F 1.54 90% NF/10% F 1.58 95%
NF/5% F 1.59
TABLE-US-00004 TABLE 4 WRV values for softwood cellulose fibers
following pre-treatment Softwood Pre-treatment Fiber Mixtures (%)
(WRV (g/g)) 100% Non-Functionalized (NF) 2.74 100% Functionalized
(F) 1.11 50% NF/50% F 1.17 75% NF/25% F 1.30 90% NF/10% F 1.29 95%
NF/5% F 1.32
[0180] As shown in FIGS. 4 and 5 and Tables 3 and 4, the effect of
water retention in fibrillation due to a loosened fiber structure
and external fibrillation due to beating is greatly reduced using
the disclosed methods. In hardwood, the effect is up to 39% and
reduces down to 29% with only 5% functionalized fibers in the fiber
test pads for WRV testing. In softwood, the effect ranged from 59%
down to 52%.
[0181] The higher WRV from softwood fibers confirm the results from
the CSF testing. Thus, the WRV and CSF tests both confirm the
effectiveness of our approach to improve the drainage phenomena.
Test results demonstrate the effect to be related to the external
fibrils that are not able to absorb water and are functioning as
highly increased effective area for reduced inter-fiber friction
and internal sliding movements and reorientation that effectively
increases drainage.
EXAMPLE 5
Sedimentation Analysis of Functionalized Cellulose Fiber
Compositions
[0182] Sediment volume formation behavior of the functionalized and
non-functionalized fibers was investigated according to the
following procedure. Three (3) grams of fibers was mixed in 997 ml
water and were then disintegrated to individual fibers using
disintegrator for 3 minutes. Thereafter, a 100 ml sample was taken
from the slurry and poured in to a 100 ml graduated cylinder.
Photographs were taken and fiber levels were recorded at specified
time intervals.
[0183] Sediment volume formation behaviors of the 100%
functionalized and non-functionalized fibers are shown in FIG. 6
and FIG. 7. Functionalized fibers are loosely aligned in the water
medium and the volume they occupy in a given mass (specific volume)
is significantly higher than that of the non-functionalized fibers
within 1 minute and within 60 minutes of sample preparation. While
a papermaking furnish is being dewatered, the consolidation of pulp
mats proceeds by a combination of thickening and filtration. During
consolidation, the flow and compression resistances of the fibrous
mats are critical to determine the dewatering rates. The volume
that is not occupied by the fibers is open (void) space and is
accessible to a fluid flowing through the porous media. Therefore,
it is expected that water drainage rate can be faster with the
pretreated, functionalized fibers since they possess higher void
space in the water medium.
[0184] As shown in FIG. 8, pretreated and functionalized fibers had
a faster initial settling rate than that of non-functionalized
fibers of 530 ml CSF. The sediment volume of functionalized fibers
level off after 10 minutes at about 75 ml and give a significantly
open fiber distribution (open space) in water in comparison to
non-functionalized fiber. Although it is possible that mat
formation is faster with the functionalized fibers, it is also
possible that open fiber distribution eases the water flow through
the paper mat in the thickening process and fibers more easily
sliding past each other, thus delaying the sealing of the mat for
water passage.
[0185] As shown in FIG. 9, non-pre-treated and non-functionalized
fibers had a faster initial settling rate than that of
non-functionalized fibers of 660 ml CSF. Thus, non-pre-treated and
non-functionalized fibers possibly form mat faster than that of
pretreated, functionalized fibers reducing water drainage. However,
the sediment volume of functionalized fibers levels off after 5
minutes at about 90 ml and give significantly open fiber
distribution in water in comparison to non-functionalized fiber.
This observed behavior further increases the water drainage
rate.
EXAMPLE 6
Evaluation of Plugging Problems in the Nano/Micro-Fibrillated
Cellulose Production Process
[0186] The fiber samples can be prepared for nano/micro-fibrillated
cellulose production using a microfluidizer. Briefly, the procedure
for microfluidizer application in nanofibrillated cellulose
production is as follows. First, 80% pretreated (2 hour PFI
refining) and TEMPO oxidized fiber is mixed with 20% functionalized
(hydrophobic) fiber. Then, the mixture is passed through the
channels of the microfluidizer. Subsequently, the system can be
evaluated to determine the presence or absence of plugging problems
of the chambers of the microfluidizer.
[0187] According to the methods of the present disclosure, the
observed results of the example demonstrate that the microfluidizer
is advantageously substantially free of problems for the production
of nanofibrillated cellulose (e.g., minimal plugging of the
chambers).
EXAMPLE 7
Thickness Analysis of Paper Samples Made from Functionalized
Cellulose Fiber Compositions
[0188] Paper samples (i.e., "handsheets") can be made according to
the art-recognized TAPPI T-205 procedure (i.e., TAPPI Test Method
No. T-205, entitled "Forming handsheets for physical tests of
pulp"). In this example, paper samples contained 100%
non-functionalized fibers, 100% functionalized fibers, or a mixture
of 5% functionalized fibers and 95% non-functionalized fibers. The
calipers (i.e., thickness) of the resultant paper samples can be
measured according to the art-recognized TAPPI T 411 procedure
(i.e., TAPPI Test Method No. T 411, entitled "Thickness (caliper)
of paper, paperboard, and combined board").
[0189] The observed thickness (caliper) values of the paper samples
created according to a paper making process utilizing methods of
the present disclosure are shown in Table 5 (hardwood) and Table 6
(softwood) below.
TABLE-US-00005 TABLE 5 Thickness (caliper) values for paper samples
made from hardwood cellulose fibers Hardwood Fiber Mixtures (%)
Thickness (mm) 100% Non-Functionalized (NF) 0.088 100%
Functionalized (F) 0.114 95% NF/5% F 0.090
TABLE-US-00006 TABLE 6 Thickness (caliper) values for paper samples
made from softwood cellulose fibers Softwood Fiber Mixtures (%)
Thickness (mm) 100% Non-Functionalized (NF) 0.091 95% NF/5% F
0.096
[0190] As shown in Table 5, paper samples produced using
functionalized hardwood cellulose fibers demonstrate an increased
thickness compared to paper samples produced using
non-functionalized hardwood cellulose fibers. The thickness values
increased with a larger percentage of functionalized cellulose
fibers in the composition. In particular, paper samples produced
using 5% functionalized hardwood cellulose fibers show a 2.26%
increase in thickness compared to paper samples produced using
non-functionalized hardwood cellulose fibers. Moreover, paper
samples produced using 100% functionalized hardwood cellulose
fibers show a 29.0% increase in thickness compared to paper samples
produced using non-functionalized hardwood cellulose fibers.
[0191] As shown in Table 6, paper samples produced using
functionalized softwood cellulose fibers demonstrate an increased
thickness compared to paper samples produced using
non-functionalized hardwood cellulose fibers. In particular, paper
samples produced using 5% functionalized hardwood cellulose fibers
show a 5.83% increase in thickness compared to paper samples
produced using non-functionalized hardwood cellulose fibers.
[0192] In summary, by using methods of the present disclosure, the
thickness of paper samples can be increased for paper products made
from both hardwood and softwood.
* * * * *