U.S. patent application number 13/975922 was filed with the patent office on 2014-02-13 for fluff pulp and high sap loaded core.
This patent application is currently assigned to International Paper Company. The applicant listed for this patent is International Paper Company. Invention is credited to BRENT A. FIELDS, PETER M. FROASS, JAMES E. SEALEY.
Application Number | 20140041818 13/975922 |
Document ID | / |
Family ID | 50065294 |
Filed Date | 2014-02-13 |
United States Patent
Application |
20140041818 |
Kind Code |
A1 |
SEALEY; JAMES E. ; et
al. |
February 13, 2014 |
FLUFF PULP AND HIGH SAP LOADED CORE
Abstract
A fluff pulp is provided, which comprises softwood fibers; and 3
to 35% by weight of hardwood fibers. A fluff is also provided,
which comprises the fiberized or shredded fluff pulp. A core is
also provided, which comprises the fluff and at least an SAP.
Processes for making and using the fluff pulp, fluff, and core are
provided, and products made thereby.
Inventors: |
SEALEY; JAMES E.; (Anderson,
SC) ; FIELDS; BRENT A.; (Trenton, OH) ;
FROASS; PETER M.; (Mason, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Paper Company |
Memphis |
TN |
US |
|
|
Assignee: |
International Paper Company
Memphis
TN
|
Family ID: |
50065294 |
Appl. No.: |
13/975922 |
Filed: |
August 26, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/US13/54528 |
Aug 12, 2013 |
|
|
|
13975922 |
|
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61681799 |
Aug 10, 2012 |
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Current U.S.
Class: |
162/13 ; 162/141;
19/305; 28/116 |
Current CPC
Class: |
D21H 11/18 20130101;
D21H 11/00 20130101; D04H 1/732 20130101; D06C 15/00 20130101; D04H
1/26 20130101; D21H 15/04 20130101 |
Class at
Publication: |
162/13 ; 162/141;
19/305; 28/116 |
International
Class: |
D21H 11/00 20060101
D21H011/00; D06C 15/00 20060101 D06C015/00; D04H 1/732 20060101
D04H001/732 |
Claims
1. A fluff pulp, comprising: softwood fibers; and 3 to 35% by
weight of hardwood fibers, wherein said pulp having a compressed
density, when in the form of a core, of greater than 0.13
g/cm.sup.3 at 161 PSI and a compressed density of greater than 0.18
at 225 PSI.
2. The fluff pulp of claim 1, comprising 5 to 30% by weight of
hardwood fibers.
3. The fluff pulp of claim 1, which comprises a moisture content of
.ltoreq.15% by weight.
4. The fluff pulp of claim 1, which comprises a basis weight of 500
to 1100 gsm.
5. A process for making fluff pulp, comprising: contacting a first
aqueous slurry comprising softwood fibers with a second aqueous
slurry comprising hardwood fibers, to form a furnish; contacting
the furnish onto a moving wire, to form a web; and drying and
optionally pressing the web, to form the fluff pulp of claim 1.
6. The process of claim 5, comprising pressing the web.
7. The process of claim 5, further comprising rolling the fluff
pulp onto a roll or cutting the fluff pulp into sheets, and
stacking the sheets to form a bale.
8. The process of claim 5, wherein said drying comprises flash
drying the web to form the fluff pulp, and thereafter bagging the
fluff pulp.
9. The process of claim 5, further comprising contacting the first
and second slurries at a blend chest.
10. The process of claim 5, further comprising and prior to
contacting the first and second slurries: forming the hardwood
fibers by one or more steps selected from the group consisting of
chipping, pulping, and bleaching hardwood, or a combination of two
or more thereof; and forming the softwood fibers by one or more
steps selected from the group consisting of chipping, pulping, and
bleaching softwood, or a combination of two or more thereof.
11. The fluff pulp of claim 1, in the form of a bale or roll, or in
a bag.
12. A fluff, comprising the fluff pulp of claim 1 in fiberized
form.
13. A process for making fluff, comprising fiberizing the fluff
pulp of claim 1.
14: The process of claim 13, which is carried out in an airlaid
line.
15. The process of claim 11, further comprising taking the fluff
pulp from a bale, roll, or bag, or combination thereof, and
fiberizing.
16. A core, comprising: the fluff of claim 12 and one or more
superabsorbent polymer (SAP).
17. The core of claim 16, wherein the SAP is selected from the
group consisting of starch-acrylonitrile copolymer, hydrolyzed
starch-acrylonitrile copolymer, acrylic acid (co)polymer,
acrylamide (co)polymer, polyvinyl alcohol,
polyacrylate/polyacrylamide copolymers, polyacrylic acid
(co)polymers, sodium polyacrylate, ethylene maleic anhydride
copolymer, cross-linked carboxymethylcellulose, polyvinyl alcohol
copolymer, polyethylene oxide, cross-linked polyethylene oxide,
starch grafted copolymer of polyacrylonitrile, salt of one or more
thereof, and combination of two or more thereof.
18. The core of claim 16, wherein the SAP is present in an amount
ranging from 1 to 85% by weight of the core.
19. A process for making a core, comprising contacting the fluff of
claim 12 and one or more superabsorbent polymer.
20. The process of claim 19, further comprising after the
contacting, forming a web, and densifying the web in a nip.
21. The process of claim 19, wherein the contacting is carried out
in an airlaid line.
22. An absorbent product, paper product, personal care product,
medical product, insulating product, construction product,
structural material, cement, food product, veterinary product,
packaging product, diaper, tampon, sanitary napkin, gauze, bandage,
fire retardant, or a combination thereof, comprising the core of
claim 13 and a supporting structure.
23. A process for making the absorbent product of claim 22,
comprising contacting at least a portion of the core with the
supporting structure.
24. The pulp of claim 1, comprising from 5 to 25 wt % of the
hardwood fibers.
25. The pulp of claim 1, comprising from 5 to 20 wt % of the
hardwood fibers.
26. The pulp of claim 1, comprising 8 to 18 wt % of the hardwood
fibers.
27. The pulp of claim 1, having a compressed thickness, when in the
form of a core, of less than 280 mil at 161 PSI and a compressed
thickness of less than 200 at 225 PSI.
28. The pulp of claim 27, having a compressed density, when in the
form of a core, of greater than 0.13 g/cm.sup.3 at 161 PSI and a
compressed density of greater than 0.18 at 225 PSI.
29. The pulp of claim 1, having a Gurley Stiffness, when in the
form of a core having about 0.31 g/cm.sup.3 density (uncompressed),
of less than 1350 mg.
30. The pulp of claim 29, further comprising a debonder.
31. The pulp of claim 30, wherein the debonder comprises at least
one debonder selected from the group consisting of a linear or
branched monoalkyl amine, linear or branched dialkyl amine, linear
or branched tertiary alkyl amine, linear or branched quaternary
alkyl amine, ethoxylated alcohol, linear or branched, saturated or
unsaturated hydrocarbon surfactant, fatty acid amide, fatty acid
amide quaternary ammonium salt, dialkyl dimethyl quaternary
ammonium salt, dialkylimidazolinium quaternary ammonium salt,
dialkyl ester quaternary ammonium salt, triethanolamine-ditallow
fatty acid, fatty acid ester of ethoxylated primary amine,
ethoxylated quaternary ammonium salt, dialkyl amide of fatty acid,
dialkyl amide of fatty acid, cationic surfactant, non-ionic
surfactant, C.sub.16-C.sub.18 unsaturated alkyl alcohol ethoxylate,
compound having CAS Registry No. 68155-01-1, and compound having
CAS Registry No. 26316-40-5.
32. The pulp of claim 1, having a Gurley Stiffness, when in the
form of a core having about 0.62 g/cm.sup.3 density (uncompressed),
of less than 6800 mg.
33. The pulp of claim 1, further comprising a debonder.
34. The pulp of claim 33, wherein the debonder comprises at least
one debonder selected from the group consisting of a linear or
branched monoalkyl amine, linear or branched dialkyl amine, linear
or branched tertiary alkyl amine, linear or branched quaternary
alkyl amine, ethoxylated alcohol, linear or branched, saturated or
unsaturated hydrocarbon surfactant, fatty acid amide, fatty acid
amide quaternary ammonium salt, dialkyl dimethyl quaternary
ammonium salt, dialkylimidazolinium quaternary ammonium salt,
dialkyl ester quaternary ammonium salt, triethanolamine-ditallow
fatty acid, fatty acid ester of ethoxylated primary amine,
ethoxylated quaternary ammonium salt, dialkyl amide of fatty acid,
dialkyl amide of fatty acid, cationic surfactant, non-ionic
surfactant, C.sub.16-C.sub.18 unsaturated alkyl alcohol ethoxylate,
compound having CAS Registry No. 68155-01-1, and compound having
CAS Registry No. 26316-40-5.
Description
BACKGROUND
Field of the Invention
[0001] The invention relates to fluff pulp, processes for making,
and uses thereof.
BRIEF DESCRIPTION OF THE FIGURES
[0002] Various embodiments are described in conjunction with the
accompanying figures, in which:
[0003] FIG. 1 shows SAP retention of exemplary and comparative
embodiments.
[0004] FIG. 2 shows mullen values of exemplary and comparative
embodiments.
[0005] FIG. 3 shows shred energy values of exemplary and
comparative embodiments.
[0006] FIG. 4 shows shred quality in percent goods and fines for
exemplary and comparative embodiments.
[0007] FIG. 5 shows shred quality in percent nits and pieces for
exemplary and comparative embodiments.
[0008] FIG. 6 shows shred absorption in absorption capacity and
rate for exemplary and comparative embodiments.
DETAILED DESCRIPTION OF THE SEVERAL EMBODIMENTS
[0009] One embodiment relates to fluff pulp, methods for making,
and uses thereof. Another embodiment relates to fluff formed from
the fluff pulp, methods for making, and uses thereof. Another
embodiment relates to a core formed from the fluff, methods for
making, and uses thereof. Another embodiment relates to products
which include one or more of the fluff pulp, fluff, and/or core,
methods for making, and uses thereof. Another embodiment relates to
a thin core formed from the fluff, methods for making, and uses
thereof. Another embodiment relates to a flexible core formed from
the fluff, methods for making, and uses thereof. Another embodiment
relates to an SAP (superabsorbent polymer) loaded core formed from
the fluff and SAP particles, methods for making, and uses thereof.
Another embodiment relates to a thin, loaded core formed from the
fluff, methods for making, and uses thereof. Another embodiment
relates to the use of hardwood fiber and softwood fiber in a fluff
pulp. Another embodiment relates to the use of hardwood fiber and
softwood fiber and a simple sugar or slightly branched sugar in the
fluff pulp or dried web. In one embodiment, the hardwood fiber will
produce a thin core with low porosity to trap the SAP particles. In
one embodiment, the short hardwood fibers limit the amount of
fiber-fiber entanglement to make the core weaker when compressed to
a very low caliper. In one embodiment, the sugar molecules can also
prevent or inhibit strong bonding between fibers when compressed by
providing a viscous fluid response. In one embodiment, prevention
or inhibition of fiber-fiber bonding and/or fiber-fiber
entanglement via one or both of the use of short hardwood fibers
and sugar molecules allows the core to change shape with the body.
In one embodiment, the sugar or sugar solution will help hold the
SAP particles in the core due to the tacky or sticky properties of
the sugar. In one embodiment, the core is flexible.
[0010] The inventors have investigated how to produce a thin and
high SAP loaded core.
[0011] One embodiment relates to an absorbent core having improved
SAP retention. Another embodiment relates to fluff pulp having good
Mullen values. Another embodiment relates to a fluff pulp having
reduced shred energy. Another embodiment relates to a fluff pulp
having improved shred quality. Another embodiment relates to a
fluff pulp having good shred absorption. Another embodiment relates
to a fluff pulp having good rewet characteristics.
[0012] One embodiment relates to a fluff pulp, comprising softwood
fibers; and 3 to 35% by weight of hardwood fibers.
[0013] One embodiment relates to a process for making fluff pulp,
comprising contacting a first aqueous slurry comprising softwood
fibers with a second aqueous slurry comprising hardwood fibers, to
form a furnish; contacting the furnish onto a moving wire, to form
a web; and drying and optionally pressing the web, to form the
fluff pulp.
[0014] One embodiment relates to a fluff, comprising the fluff pulp
in fiberized form.
[0015] One embodiment relates to a process for making fluff,
comprising fiberizing the fluff pulp.
[0016] One embodiment relates to a core, comprising the fluff and
one or more superabsorbent polymer (SAP).
[0017] One embodiment relates to a process for making a core,
comprising contacting the fluff of and one or more superabsorbent
polymer.
[0018] One embodiment relates to an absorbent product, paper
product, personal care product, medical product, insulating
product, construction product, structural material, cement, food
product, veterinary product, packaging product, diaper, tampon,
sanitary napkin, gauze, bandage, fire retardant, or a combination
thereof, comprising the core and a supporting structure.
[0019] One embodiment relates to a process for making an absorbent
product, comprising contacting at least a portion of the core with
the supporting structure.
[0020] One embodiment relates to a process for making a fluff pulp,
comprising forming a web comprising hardwood and softwood fibers,
and drying, to produce a fluff pulp having softwood fibers and 3 to
35% by weight of hardwood fibers.
[0021] In one embodiment, the forming comprises one or more of
contacting a fluff pulp mixture comprising fluff pulp fibers and
water with a table in a papermaking machine, removing at least a
portion of water from a fluff pulp mixture comprising fluff pulp
fibers and water with a suction box under a table in a papermaking
machine, at least partially drying a fluff pulp mixture comprising
fluff pulp fibers and water in a flotation dryer, heating a fluff
pulp mixture comprising fluff pulp fibers and water, or a
combination thereof.
[0022] In embodiment, the web may be dried in a dryer, to form the
dried web or fluff pulp. The web may be suitably dried in a drying
section. Any method for drying commonly known in the art of fluff
pulp papermaking may be utilized. The drying section may include a
drying can, flotation dryer, cylinder drying, Condebelt drying, IR,
or other drying means and mechanisms known in the art. The fluff
pulp may be dried so as to contain any selected amount of water. In
one embodiment, the web is dried using a flotation dryer.
[0023] As used herein, the term, "fluff pulp" may be used
interchangeably with "dried web". Unless otherwise specified, the
percent by weight or weight percent is based on the weight of the
fluff pulp, fluff, or core as appropriate. As used herein, the
term, "fluff" means fiberized or shredded fluff pulp, the terms,
"fiberized" and "shredded" are used interchangeably herein, as is
common in the art. As used herein, the term, "core" means a
composition comprising fluff and at least SAP particles.
[0024] In one embodiment, the fluff pulp may have a basis weight
ranging from 500 to 1100 gsm. This range includes all values and
subranges therein, for example 500, 525, 550, 575, 600, 625, 650,
675, 700, 725, 750, 757, 775, 800, 825, 850, 875, 900, 950, 1000,
1150, and 1100 gsm, or any combination thereof or range
therein.
[0025] In one embodiment, the fluff pulp has a moisture content of
15% by weight or less. This range includes all values and subranges
therebetween, including 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,
0.9, 1, 2, 3, 4, 5, 6, 6.3, 7, 8, 8.5, 9, 10, 11, 12, 13, 14, and
15% by weight, or any combination thereof or range therein. In
another embodiment, the fluff pulp has a moisture content of 20% or
less. In another embodiment, the fluff pulp has a moisture content
of 10% or less. In another embodiment, the fluff pulp has a
moisture content of 6 to 9%. In another embodiment, the fluff pulp
has a moisture content of about 6.3 to 8.5%. Moisture content may
be suitably measured using TAPPI T 412 standard.
[0026] In one embodiment, the fluff pulp has a density of 0.1 to
0.75 g/cc (not compressed by the Compressibility Test (defined
below). This range includes all values and subranges therebetween,
including 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55,
0.6, 0.65, 0.7, and 0.75 g/cc, or any range therein.
[0027] In one embodiment, the fluff pulp has a caliper of 0.5-3 mm.
This range includes all values and subranges therebetween,
including 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5,
1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.3, 2.5, 2.7, 2.9, and 3 mm, and any
range therein. In one embodiment, the fluff pulp has a caliper of
1.1 to 1.5 mm. In one embodiment, the fluff pulp has a caliper of
1.3.+-.0.2 mm.
[0028] The fiberization energy, sometimes called the shred energy,
of the fluff pulp is not particularly limited. It may be suitably
less than 170 kJ/kg. This range includes all values and subranges
therebetween, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25,
30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105,
110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, and 170
kJ/kg, or any combination thereof or any range therein. In one
embodiment, the fiberization energy of the fluff pulp is equal to
or less than 160 kJ/kg. In another embodiment, the fiberization
energy of the fluff pulp is from 100 to 160 kJ/kg. In another
embodiment, the fiberization energy of the fluff pulp is from 120
to 160 kJ/kg.
[0029] In one embodiment, the fluff pulp has a Mullen of .gtoreq.90
psi. This range includes all values and subranges therebetween,
including 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145,
150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210,
215, 220, 225, 230, 235, 240, 245, 250 psi, and higher, or any
range therein. Mullen may be easily determined according to TAPPI T
807.
[0030] In one embodiment, the SAP retention is greater than about
60%, greater than about 65%, greater than about 70%, greater than
about 75%, greater than about 80% or greater than about 85%,
greater than about 90%, including without limitation 80, 81, 82,
83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99,
and 100%, including any and all ranges and subranges therein.
[0031] In one embodiment the fluff pulp has a greater
compressibility as measured by the compressed pad thickness and
density using the Compressibility Test (defined below in Example 2)
at a predetermined pressure load of 161 PSI or 225 PSI. The
compressed thickness under 161 PSI may be less than about 280 mil,
less than about 270 mil, less than about 260 mil less than about
250 mil, less than about 245 mil, less than about 240 mil, less
than about 235 mil less than about 230 mil, less than about 225
mil, less than about 220 mil, less than about 215 mil less than
about 210 mil, including without limitation 230, 229, 228, 227,
226, 225, 224, 223, 222, 221, 220, 219, 218, 217, 216, 215, 214,
213, 212, 211, 210, and less than 209 mil, including any and all
ranges and subranges therein. The compressed thickness under 225
PSI may be less than about 205, less than about 200 mil, less than
about 190 mil less than about 180 mil, less than about 175 mil,
less than about 170 mil, less than about 165 mil less than about
160 mil, less than about 155 mil, less than about 150 mil including
without, including without limitation 180, 179, 178, 177, 176, 175,
174, 173, 172, 171, 170, 169, 168, 167, 166, 165, 164, 163, 162,
161, 160, and less than about 159 mil, including any and all ranges
and subranges therein. The compressed density under 161 PSI may be
greater than about 0.13 g/cm.sup.3, greater than about 0.14
g/cm.sup.3, greater than about 0.15 g/cm.sup.3, greater than about
0.16 g/cm.sup.3, greater than about 0.17 g/cm.sup.3, greater than
about 0.18 g/cm.sup.3, greater than about 0.19 g/cm.sup.3, greater
than about 0.20 g/cm.sup.3, including including any and all ranges
and subranges therein. The compressed density under 225 PSI may be
greater than 0.18 g/cm.sup.3, greater than about 0.19 g/cm.sup.3,
greater than about 0.20 g/cm.sup.3, greater than 0.21 g/cm.sup.3,
greater than about 0.22 g/cm.sup.3, greater than about 0.23
g/cm.sup.3, greater than 0.24 g/cm.sup.3, greater than about 0.25
g/cm.sup.3, including any and all ranges and subranges therein.
[0032] In one embodiment, the Gurley Stiffness of the fluff pulp as
measured by the Gurley Stiffness (defined below in Example 2) of
the pad (the pad may have any density including without limitation
a pad having a density of 0.31 g/cm.sup.3 or a pad having a density
of 0.62 g/cm.sup.3) may be less than about 750 mg, less than about
800 mg, less than about 850 mg, less than about 900 mg, less than
about 1000 mg, less than about 1200 mg, less than about 1300 mg,
less than about 1400 mg, less than about 1500 mg, less than about
1600 mg, less than about 1700 mg, less than about 1800 mg, less
than about 2000 mg, less than about 2200 mg, less than about 2400
mg, less than about 2500 mg, less than about 3000 mg, less than
about 4000 mg, less than about 5000 mg, less than about 5500 mg,
less than about 6000 mg, including any and all ranges and subranges
therein. In one embodiment, the fluff pulp further comprises one or
more additive such as whitener, colorant, pigment, optical
brightening agent, wetting agent, binder, bleaching agent, other
additive, or a combination thereof. If present, the amount of
additive is not particularly limited. In one embodiment, the
additive may be present in amounts ranging from about 0.005 to
about 50 by weight. This range includes all values and subranges
therebetween, including about 0.005, 0.006, 0.007, 0.008, 0.009,
0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2,
0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
15, 20, 25, 30, 35, 40, 45, and 50 weight percent, or any
combination thereof, based on the weight of the fluff pulp
mixture.
[0033] The fluff pulp may or may not include a debonder surfactant.
In one embodiment, the fluff pulp includes one or more debonder
surfactants. In another embodiment, the fluff pulp does not include
a debonder surfactant. If present, the debonder surfactant may be
present in an amount of .gtoreq.0.1 lb solids debonder surfactant
per ton of fluff pulp. This range includes all values and subranges
there between, including .gtoreq.0.1, 0.15, 0.2, 0.25, 0.3, 0.35,
0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95,
1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.0, 2.1, 2.2,
2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5,
3.6, 3.7, 3.8, 3.9, 4, 4.0, 5, 5.0, 6, 7, 8, 9, 10, 15, 20 lb
solids debonder surfactant per ton of the fluff pulp, and higher,
or any combination thereof or any range therein. In one embodiment,
if more than one debonder surfactant is used, this range is the
total amount over all the debonder surfactants present in the fluff
pulp.
[0034] Debonder surfactants are known in the fluff pulp and fluff
pulp fiber arts. Any debonder surfactant is suitable for use in the
present application, and the selection thereof is within the skill
of one knowledgeable in the fluff pulp and fluff pulp fiber arts.
Some examples, which are not intended to be limiting, include
linear or branched monoalkyl amine, linear or branched dialkyl
amine, linear or branched tertiary alkyl amine, linear or branched
quaternary alkyl amine, ethoxylated alcohol, linear or branched,
saturated or unsaturated hydrocarbon surfactant, fatty acid amide,
fatty acid amide quaternary ammonium salt, dialkyl dimethyl
quaternary ammonium salt, dialkylimidazolinium quaternary ammonium
salt, dialkyl ester quaternary ammonium salt,
triethanolamine-ditallow fatty acid, fatty acid ester of
ethoxylated primary amine, ethoxylated quaternary ammonium salt,
dialkyl amide of fatty acid, dialkyl amide of fatty acid, cationic
surfactant, non-ionic surfactant, C.sub.16-C.sub.18 unsaturated
alkyl alcohol ethoxylate, commercially available compound having
CAS Registry No. 68155-01-1, commercially available compound having
CAS Registry No. 26316-40-5, commercially available F60.TM.,
commercially available Cartaflex TS LIQ.TM., commercially available
F639.TM., commercially available Hercules PS9456.TM., commercially
available Cellulose Solutions 840.TM., commercially available
Cellulose Solutions 1009.TM., commercially available EKA 509H.TM.,
commercially available EKA 639.TM., alone, or in any combination.
Other examples of debonder surfactants are disclosed in U.S. Pat.
No. 4,425,186, the contents of which being hereby incorporated by
reference.
[0035] In one embodiment, the finished fluff pulp may be fiberized
or shredded, in accordance with methods known in the art. For
example, the fiberizing or shredding may be carried out in a
hammermill.
[0036] In one embodiment, the fluff pulp and/or fiberized or
shredded fluff pulp, or core, or a combination thereof may be
suitably incorporated into one or more of an absorbent product,
paper product, personal care product, medical product, insulating
product, construction product, structural material, cement, food
product, veterinary product, packaging product, diaper, tampon,
sanitary napkin, gauze, bandage, fire retardant, or a combination
thereof. These products and methods for their manufacture and use
are well known to those of ordinary skill in the art.
[0037] Another embodiment relates to a fluff pulp, made by the
process described herein.
[0038] Another embodiment relates to an absorbent product, paper
product, personal care product, medical product, insulating
product, construction product, structural material, cement, food
product, veterinary product, packaging product, diaper, tampon,
sanitary napkin, gauze, bandage, fire retardant, or a combination
thereof, comprising the fluff pulp and/or fiberized or shredded
fluff pulp, or core, or a combination thereof.
[0039] Another embodiment relates to the use of an absorbent
product, paper product, personal care product, medical product,
insulating product, construction product, structural material,
cement, food product, veterinary product, packaging product,
diaper, tampon, sanitary napkin, gauze, bandage, fire retardant, or
a combination thereof, comprising the fluff pulp and/or fiberized
or shredded fluff pulp, or core, or a combination thereof.
[0040] One or more than one, or any combination thereof, of fibers
may be used in the fluff pulp. The fibers may be treated or
untreated, and they may optionally contain one or more than one
additives, or combination thereof, which are known in the art.
Given the teachings herein, the level of treatment, if desired, and
the amount of additives may be readily determined by one of
ordinary skill in the fluff pulp and fluff pulp fiber arts.
[0041] Similarly, the formation of a web of fluff pulp or fluff
pulp fibers or from a fluff pulp mixture or furnish onto a table
from a headbox in a papermaking machine is within the skill of one
knowledgeable in the fluff pulp and fluff pulp fiber arts.
[0042] The type of fluff pulp or fluff pulp fiber suitable for use
herein is not intended to be limiting. Fluff pulp typically
includes cellulosic fiber. The type of cellulosic fiber in the
fluff pulp is not critical. For example, the fluff pulp can be made
from pulp fibers derived from hardwood trees, softwood trees, or a
combination of hardwood and softwood trees. The fluff pulp may also
include synthetic fibers, in addition to one or more types of
cellulosic fibers. The fluff pulp fibers may be prepared by one or
more known or suitable digestion, refining, and/or bleaching
operations such as, for example, known mechanical,
thermomechanical, chemical and/or semichemical pulping and/or other
well known pulping processes. The term, "hardwood pulps" as may be
used herein include fibrous pulp derived from the woody substance
of deciduous trees (angiosperms) such as birch, oak, beech, maple,
and eucalyptus. The term, "softwood pulps" as may be used herein
include fibrous pulps derived from the woody substance of
coniferous trees (gymnosperms) such as varieties of fir, spruce,
and pine, as for example loblolly pine, slash pine, Colorado
spruce, balsam fir and Douglas fir. In some embodiments, at least a
portion of the pulp fibers may be provided from non-woody
herbaceous plants including, but not limited to, kenaf, hemp, jute,
flax, sisal, or abaca, although legal restrictions and other
considerations may make the utilization of hemp and other fiber
sources impractical or impossible. Either bleached or unbleached
fluff pulp fiber may be utilized. Recycled fluff pulp fibers are
also suitable for use. The fluff pulp may suitably contain from 30
to 100 wt % of fluff pulp fibers based upon the total weight of the
fluff pulp. In one embodiment, the fluff pulp may contain from 30
to 99 wt % of fluff pulp fibers based upon the total weight of the
fluff pulp. In another embodiment, the fluff pulp contains 40 to 95
wt % of fluff pulp fibers based upon the total weight of the fluff
pulp. These ranges include any and all values and subranges
therebetween, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75,
80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100 wt % or any
subrange therein, based upon the total weight of the fluff
pulp.
[0043] The fluff pulp may optionally contain from 65 to 97 wt %
fluff pulp fibers originating from softwood species based upon the
total weight of the fluff pulp. In one embodiment, the fluff pulp
may contain 70 to 94 wt % fluff pulp fibers originating from
softwood species. These ranges include 65, 66, 67, 68, 69, 70, 71,
72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88,
89, 90, 91, 92, 93, 94, 95, 96, and 97 wt % or any subrange
therein, based upon the total weight of the fluff pulp.
[0044] All or part of the softwood fibers may optionally originate
from softwood species having a Canadian Standard Freeness (CSF) of
from 500 to 800. In one embodiment, the fluff pulp contains fluff
pulp fibers from a softwood species having a CSF from 500 to 800.
These ranges include any and all values and subranges therebetween,
for example, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400,
410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530,
540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660,
670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790,
and 800 CSF or any subrange therein. Canadian Standard Freeness is
as measured by TAPPI T-227 standard test.
[0045] The fluff pulp may optionally contain from 3 to 35 wt %
fluff pulp fibers originating from hardwood species. These ranges
include 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, and
35 wt %, or any subrange therein, based upon the weight of the
fluff pulp.
[0046] All or part of the hardwood fibers may optionally originate
from hardwood species having a Canadian Standard Freeness of from
500 to 650. This range includes 500, 510, 520, 530, 540, 550, 560,
570, 580, 590, 600, 610, 620, 630, 640, and 650 CSF, or any
subrange therein.
[0047] In one embodiment, where only hardwood and softwood fibers
are present in the fluff pulp, the hardwood/softwood fluff pulp
fiber weight ratio may range from 3/97 to 35/65. These ranges
include all values and subranges therebetween, including 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, and 35 (for hardwood)
to 100 minus the aforementioned values (for softwood).
[0048] The softwood fibers, hardwood fibers, or both may be
optionally modified by physical and/or chemical processes to obtain
the fluff pulp. Examples of physical processes include, but are not
limited to, electromagnetic and mechanical processes. Examples of
electrical modifications include, but are not limited to, processes
involving contacting the fibers with an electromagnetic energy
source such as light and/or electrical current. Examples of
mechanical modifications include, but are not limited to, processes
involving contacting an inanimate object with the fibers. Examples
of such inanimate objects include those with sharp and/or dull
edges. Such processes also involve, for example, cutting, kneading,
pounding, impaling, and the like, and combinations thereof.
[0049] If present, the synthetic fibers are not particularly
limiting. Non-limiting examples of such fibers include
polyethylene, polypropylene, polyvinyl alcohol, core/sheath fibers,
bi-component fibers, bi-component or core/sheath fibers of
polyethylene and polypropylene. Combinations of different synthetic
fibers are possible.
[0050] A simple sugar or slightly branched sugar may optionally be
present in the fluff pulp, fluff, or core. Nonlimiting examples
include sucrose, fructose, dextrose, hexose, L-arabinose,
oligosaccharide, monosaccharide, disaccharide, glucose, galactose,
maltose, lactose, sugar pulp, bagasse, sugar cane pulp, sugar beet
pulp, or combination thereof. If present, the sugar may be present
in an amount ranging from 1 to 40% by weight, which range includes
all values and subranges therebetween, including 1, 5, 10, 15, 20,
25, 30, 35, and 40% by weight or any combination thereof or
subrange therein. The sugar, if desired, may be added at any point
during the making of fluff pulp, fluff, and/or core. In one
embodiment, the sugar may be contacted with the fluff pulp before,
during, or after an airlaid process, or a combination thereof.
[0051] Nonlimiting examples of chemical modifications include
conventional chemical fiber processes such as bleaching,
crosslinking and/or precipitation of complexes thereon. Other
examples of suitable modifications of fibers include those found in
U.S. Pat. Nos. 6,592,717, 6,592,712, 6,582,557, 6,579,415,
6,579,414, 6,506,282, 6,471,824, 6,361,651, 6,146,494, H1,704,
5,731,080, 5,698,688, 5,698,074, 5,667,637, 5,662,773, 5,531,728,
5,443,899, 5,360,420, 5,266,250, 5,209,953, 5,160,789, 5,049,235,
4,986,882, 4,496,427, 4,431,481, 4,174,417, 4,166,894, 4,075,136,
and 4,022,965, the entire contents of each of which are hereby
incorporated, independently, by reference.
[0052] As discussed herein, if desired, additives such as pH
adjusting agent, whitener, colorant, pigment, optical brightening
agent, wetting agent, binder, bleaching agent, trivalent cationic
metal, alum, other additive, or a combination thereof may be
utilized. Such compounds are known in the art and otherwise
commercially available. Given the teachings herein, one of ordinary
skill in the fluff pulp and fluff pulp papermaking arts would be
able to select and use them as appropriate. If present, the amount
of additive is not particularly limited. In one embodiment, the
additive may be present in amounts ranging from about 0.005 to
about 20 weight percent based on the weight of the fluff pulp. This
range includes all values and subranges therebetween, including
about 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.02, 0.03, 0.04,
0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, and 20 weight percent,
or any combination thereof or subrange therein, based on the weight
of the finished fluff pulp.
[0053] One or more optical brightening agents may be optionally
present. Typically, the optical brightening agents are fluorescent
dyes or pigments that absorb ultraviolet radiation and reemit it at
a higher wavelengths in the visible spectrum (blue), thereby
effecting a white, bright appearance to the fluff pulp, but any
optical brightening agent may be used. Examples of optical
brighteners include, but are not limited to azoles, biphenyls,
coumarins, furans, stilbenes, ionic brighteners, including anionic,
cationic, and anionic (neutral) compounds, such as the
Eccobrite.TM. and Eccowhite.TM. compounds available from Eastern
Color & Chemical Co. (Providence, R.I.); naphthalimides;
pyrazenes; substituted (e.g., sulfonated) stilbenes, such as the
Leucophor.TM. range of optical brighteners available from the
Clariant Corporation (Muttenz, Switzerland), and Tinopal.TM. from
Ciba Specialty Chemicals (Basel, Switzerland); salts of such
compounds including but not limited to alkali metal salts, alkaline
earth metal salts, transition metal salts, organic salts and
ammonium salts of such brightening agents; and combinations of one
or more of the foregoing agents.
[0054] Examples of optional fillers include, but are not limited
to, clay, calcium carbonate, calcium sulfate hemihydrate, and
calcium sulfate dehydrate, chalk, GCC, PCC, and the like.
[0055] Examples of optional binders include, but are not limited
to, polyvinyl alcohol, Amres (a Kymene type), Bayer Parez,
polychloride emulsion, modified starch such as hydroxyethyl starch,
starch, polyacrylamide, modified polyacrylamide, polyol, polyol
carbonyl adduct, ethanedial/polyol condensate, polyamide,
epichlorohydrin, glyoxal, glyoxal urea, ethanedial, aliphatic
polyisocyanate, isocyanate, 1,6 hexamethylene diisocyanate,
diisocyanate, polyisocyanate, polyester, polyester resin,
polyacrylate, polyacrylate resin, acrylate, and methacrylate. Other
optional substances include, but are not limited to silicas such as
colloids and/or sols. Examples of silicas include, but are not
limited to, sodium silicate and/or borosilicates.
[0056] The composition may optionally and additionally include one
or more pigments. Non-limiting examples of pigments include calcium
carbonate, kaolin clay, calcined clay, aluminum trihydrate,
titanium dioxide, talc, plastic pigment, ground calcium carbonate,
precipitated calcium carbonate, amorphous silica, modified calcium
carbonate, modified calcined clay, aluminum silicate, zeolite,
aluminum oxide, colloidal silica, colloidal alumina slurry,
modified calcium carbonate, modified ground calcium carbonate,
modified precipitated calcium carbonate, or a mixture thereof.
[0057] The fluff pulp fibers may be formed into a single or
multi-ply web on a papermaking machine such as a Fourdrinier
machine or any other suitable papermaking machine known in the art.
The basic methodologies involved in making fluff pulps on various
papermaking machine configurations are well known to those of
ordinary skill in the art and accordingly will not be described in
detail herein. In one embodiment, one or more of the fluff pulp
furnish, hardwood slurry, and softwood slurry may have the form of
a relatively low consistency aqueous slurry of the pulp fibers
optionally together with one or more additives. In one embodiment,
the fluff pulp furnish is ejected from a head box onto a table,
e.g., a porous endless moving forming sheet or wire, where the
liquid, e.g., water, is gradually drained through small openings in
the wire, optionally with the aid of one or more suction boxes,
until a mat of pulp fibers and optionally the other materials is
formed on the wire. In one embodiment, the still-wet web is
transferred from the wire to a wet press where more fiber-to-fiber
consolidation occurs and the moisture is further decreased. In one
embodiment, the web is then passed to a dryer section to remove a
portion of, most of, or substantially all of the retained moisture
and further consolidate the fibers in the web. After drying, the
dried web or fluff pulp may be further treated with a formation
shower, spray boom, or the like.
[0058] If desired, the fluff pulp may be rolled onto a roll, to
form a roll of fluff pulp, or it may be cut into sheets, and
stacked, to form a bale of the fluff pulp. Alternatively, the (wet)
web may be sent to a flash dryer or similar, and dried therein, and
thereafter bagged, to form a bag containing the fluff pulp.
[0059] The fluff pulp, once obtained, may be fiberized or shredded
to produce fluff. Fluff includes the fluff pulp in fiberized
form.
[0060] In one embodiment, the fluff has a multi-dose rewet value of
3 to 8 grams for the second and third dose. This range includes all
values and subranges therebetween, including 3, 3.5, 4, 4.5, 5,
5.25, 5.5, 5.75, 6, 6.25, 6.5, 6.75, 7, 7.5, and 8 grams.
[0061] In one embodiment, the fluff has a SCAN-C 33:80 adsorption
time of <4.0 s. This range includes all values and subranges
therebetween, including 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8,
1.9, 2, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.0,
3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, <4.0 s, or any
range therein.
[0062] In one embodiment, the fluff has an absorptive capacity of 4
to 10 g/g. This range includes all values and subranges
therebetween, including 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9,
9.5, and 10 g/g, or any range therein. Absorptive capacity,
sometimes called shred absorption, may be suitably measured using
the Scan Absorption Test described herein.
[0063] In one embodiment, the fluff on screen fractionation has a %
Good of .gtoreq.50%. This range includes all values and subranges
therebetween, including 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,
100%, or any range therein.
[0064] In one embodiment, the fluff on screen fractionation has a %
Fines of .ltoreq.40%. This range includes all values and subranges
therebetween, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25,
30, 35, 40%, or any combination thereof or any range therein.
[0065] In one embodiment, the fluff on screen fractionation has a %
Pieces of .ltoreq.30%. This range includes all values and subranges
therebetween, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25,
30%, or any combination thereof or any range therein.
[0066] One embodiment relates to a core, comprising the fluff and
one or more superabsorbent polymer (SAP).
[0067] One embodiment relates to a process for making a core,
comprising contacting the fluff of and one or more superabsorbent
polymer.
[0068] In the course of making the core, the fluff may be combined
with one or more superabsorbent polymers (SAP). SAPs are known in
the absorbent product art, and are not particularly limited.
Nonlimiting examples of SAPs include starch-acrylonitrile
copolymer, hydrolyzed starch-acrylonitrile copolymer, acrylic acid
(co)polymer, acrylamide (co)polymer, polyvinyl alcohol,
polyacrylate/polyacrylamide copolymers, polyacrylic acid
(co)polymers, sodium polyacrylate, ethylene maleic anhydride
copolymer, cross-linked carboxymethylcellulose, polyvinyl alcohol
copolymer, polyethylene oxide, cross-linked polyethylene oxide, and
starch grafted copolymer of polyacrylonitrile, salts thereof, and
combination thereof.
[0069] The amount of SAP in the core is not particularly limited,
and may suitably range from 1 to 95% by weight of the core. This
range includes all values and subranges therebetween, including 1,
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,
90, and 95% by weight of the core. In one embodiment, a "high"
amount of SAP load is .gtoreq.50% by weight of the core.
[0070] The SAP may suitably be contacted with the fluff during an
airlaid process, in the course of making the core.
[0071] In one embodiment, the core has a caliper of 2 to 500 mm.
This range includes all values and subranges therebetween,
including 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 75, 100, 150,
200, 250, 300, 400, and 500, and any range therein. In one
embodiment, the core has a caliper of 2 to 50 mm. In one
embodiment, a "thin" caliper for the core is 2 to 25 mm.
[0072] In one embodiment, porosity is related to the bulk of the
core. In one embodiment, higher porosity is associated with a
higher bulk; and a lower porosity is associated with a lower bulk.
The unit of measurement for porosity is seconds, which is the
length of time required for a given amount of air to pass through a
sample. A higher porosity sample will allow a given amount of air
to pass through more quickly than would a lower porosity sample. In
one embodiment, a higher proportion of hardwood results in a higher
density and also a lower porosity. For example, typical bulk values
of 1 1-5 cc/g are observed for most papers, and 6 cc/g would be
considered high.
[0073] In one embodiment, the core may have a bulk value of 2 to 6
cc/g. This range includes all values and subranges therebetween,
including 2, 3, 4, 5, 6 cc/g, or any subrange therein.
[0074] In one embodiment, the core can be produced in an airlaid
process. This can involve one or more steps of fiber defibration,
web formation, web bonding, or a combination of two or more
thereof.
[0075] In fiber defibration, the fluff pulp or dried web may be fed
into one or more hammermills, saw mills, and/or pin mills, or any
combination thereof. They may have a series of series of saws, or
pins, or small hammers, for example, that rotate at high speed
separating the pulp into individual loose fibers. The fibers are
then transported to the web forming system. Synthetic fibers,
natural fibers, or both synthetic and natural fibers can also be
added at this stage. These may arrive in compact bale form and fed
into bale opening systems which loosen and separate the bales into
individual fibers.
[0076] In web formation, any known forming technologies may be used
to produce airlaid webs of fluff. In one embodiment, the fiberized
fluff pulp fibers are sifted through a coarse screen and deposited
with vacuum assistance onto a forming wire below. In another
embodiment, drum formers may be used, wherein fibers pass through a
series of holes or slots in a large cylinder that spans the width
of the forming wire. In one embodiment, the fluff web is kept in
place by a vacuum system located below the forming wire, and
additives, such as superabsorbent polymers or odor control powders,
can be incorporated into the web at this stage.
[0077] More than one web former may be utilized to allow for
flexibility in the web formation and increase line throughput. The
technology often allows for the web composition and structure to be
controlled to achieve various required functions. Prior to bonding,
the web may be compacted by large rollers to provide some integrity
and cohesiveness. It can also be embossed with a design or logo as
required by the customer.
[0078] For bonding and web consolidation, any method may be used as
desired. For example, latex, thermal and/or hydrogen bonding may be
utilized. In one embodiment, multi-bonding, wherein more than one
bonding method is used in combination. In one embodiment, latex and
thermal bonding may be used in combination. Other combinations are
possible.
[0079] Latex bonding may be utilized to bond the web, wherein latex
binder is contacted with the web. In one embodiment, the top of the
compacted web is sprayed with latex, and dried in an oven; and then
the web is flipped over so that it can be sprayed on the other
side. It then goes through a second oven that dries and cures the
binder before the web is cooled, slit and wound into rolls. In
another embodiment, a latex foam is utilized instead of a
spray.
[0080] In thermal bonding, synthetic bonding fibers are present. In
one embodiment, the synthetic bonding fibers include bi-component
fibers with polyethylene and polypropylene. In one embodiment,
after compaction the web is transported into an oven which softens
and melts the sheaths of the fibers such that they fuse together
and bond the various components of the web. The web may then be
calendered if desired to the correct thickness, cooled and
transported to the slitting/rewinding system.
[0081] In hydrogen-bonding, cellulose fibers bond together when
naturally occurring moisture contained in the fibers is removed
while the fibers are in close contact. This may be suitably carried
out under conditions of high temperature and pressure. Synthetic
binders may be added to the airlaid web or eliminated from the
airlaid web.
[0082] In one embodiment of multi-bonding, a combination of latex
and thermal bonding is used; the web is thermally bonded, and latex
is sprayed on both sides of the web, if desired, to reduce the lint
that is often released in high-speed converting operations.
[0083] The fluff or core may be suitably used in an absorbent
product, paper product, personal care product, medical product,
insulating product, construction product, structural material,
cement, food product, veterinary product, packaging product,
diaper, tampon, sanitary napkin, gauze, bandage, fire retardant, or
a combination thereof, comprising the fluff pulp and/or fiberized
or shredded fluff pulp, or core, or a combination thereof. These
products typically include the fluff or core (as a whole or a part
of the absorptive portion) and one or more supporting structures or
materials.
[0084] For example, a supporting structure or material may include
one or more non-woven, non-woven layer, non-woven top sheet,
wicking layer, film, back sheet, moisture barrier, non-porous
layer, acquisition distribution layer, or the like, or combination
thereof. The supporting structure or material may or may not
provide a supporting function to the core; for example, it may
simply contain the core, or provide a barrier between the user and
the core, or between the core and the environment. A feminine
hygiene pad may include the core and a non-woven and/or wickine
layer between the core and the skin of the user; and a back sheet
or moisture barrier on the backside thereof to mitigate or prevent
fluid loss or staining; and optionally one or more wings, adhesive
strip, deodorant, and the like. A tampon may include the core,
non-woven or wicking material between the core and the user; a
string for removal, and optionally an insertion device including a
barrel, grip, plunger, or similar. A diaper may include the core
and a non-woven layer, wicking layer, or the like, and a non-porous
outer layer, such as a polypropylene or polyethylene outer layer. A
medical product may include the core and a non-woven or wicking
layer between the core and the user, and a backing optionally
non-porous layer. A bandage can further include an adhesive layer
to adhere the bandage containing the core to the skin. An oil boom
might include a mesh or porous layer surrounding all or a portion
of the core. Such supporting structures are known in the art. Given
the teachings herein, combined with the knowledge of one of the
ordinary skill in the relevant art, one could easily produce an
absorptive product comprising at least the core and the supporting
structure.
[0085] Shred Energy Procedure. For fluff pulp shredding, the Kamas
hammermill is a simulation of commercial equipment manufactured and
supplied by Kamas Industri AB for use in the production of fluff
pulp products. Like the commercial equipment it has variable rotor
speed, variable pulp feed speed and exchangeable screens. Pulp
strips are hand fed into the mill and are defiberized with free
swinging hammers until the resultant fluff is sufficiently broken
up to pass through the screen holes. In the fluff testing room,
controlled conditions, 72.degree. F. and 55% (+/-5) relative
humidity are used; and for apparatus, a Kamas Type H 01 Laboratory
Defribrator was used. Samples were prepared by conditioning pulp
sheets in the testing room for at least 4 hours. For lab formed
sheets, trim about 1/2'' from edges. Cut pulp sheets (in machine
direction) into strips, 5-10 strips/sample, 2 inches wide. Record
weights. Air flow when running should be 32.5-35 L/sec.; Set rotor
to 3300 rpm, feed to .about.15 cm/sec, time to 7 seconds, and use
10 mm screen unless otherwise specified; Feed in the next sample
strip and repeat; Collect the shredded pulp in the screen receptor
funnel; Empty fluff into plastic bag; Mix by hand, then seal bag
and shake vigorously to get a homogenous fluff mix.
[0086] Shred Quality: Four Screen Fractionation of Shredded Fluff
Pulp test can determine the size distribution of fibers in dry
shredded pulp. A moving high velocity air stream disperses shredded
pulp in a covered standard testing sieve while individual fibers
are removed through the wire mesh by an applied vacuum. The amount
of fluff retained on the sieve wire is determined by weight. The
fiber is subjected to fractionation through a series of sieves with
consecutively increasing hole openings. The fractions are
calculated as a percentage of the original whole fluff weight. The
apparatus includes pulp fluff air turbulence generator and
separator; USA Standard Testing Sieves: 8'' diameter.times.2''
height; USA Std #200 (75 .mu.m hole opening); USA Std #50 (300
.mu.m hole opening); USA Std #14 (1400 .mu.m hole opening); USA Std
#8 (2360 .mu.m hole opening. This test must be conducted in a
controlled room, 48% to 52% relative humidity, 70.degree. F. to
72.degree. F.
[0087] Procedure: (1) Condition shredded pulp at least 4 hrs in the
test room. Mix the fluff in the plastic bag by hand and by
vigorously shaking the sealed bag which contains air space, to
achieve a uniform a distribution of fiber fractions and to achieve
a representative test sample. (2) Take pulp from various areas of
the bag, and weigh out 5 grams (+/-0.01 grams). Record weight, and
place on a tared #200 sieve. Place sieve on the fluff fractionator
and cover. Seal the seam formed by the sieve with the large rubber
gasket to allow a more uniform distribution of the air/vacuum. (3)
Set timer for 5 minutes and start fractionator. Adjust compressed
air to 30 psi and vacuum to 4 inches. The fines will pass through
the sieve into the vacuum. When finished, remove the sieve, remove
the cover and weigh the sieve plus the pulp on the tared balance.
Record the weight of pulp remaining on the #200 sieve. The mass of
the fines is the difference in the mass of the pulp before and
after fractionation. (4) Tare the #50 sieve and transfer the pulp
from step 3 on to the #50 sieve, cover, place on fractionator and
seal. Set timer for 5 minutes; Start fractionator and proceed as in
step 3 (adjust air and vacuum as needed). Record the weight of the
pulp retained on the #50 screen. (5) Tare the #14 sieve and
transfer the pulp from the #50 on to the #14 sieve, cover, place on
fractionator and seal as in step 2. Set timer for 5 minutes. Reset
the start by turning the knob to off, then back to auto. Start
fractionator and proceed as in step 3 (adjust air and vacuum as
needed). Record weight of the pulp retained on the #14 screen. (6)
Transfer the pulp from the #14 to the #8 screen. Repeat the process
above (5 minutes, 30 psi, vacuum at 4 in.) and record the weight of
pulp retained on the #8. Calculations: For the calculations, (1)
Original fluff weight; (2) Weight remaining on #200; (3) Weight
remaining on #50; (4) Weight remaining on #14; and (5) Weight
remaining on #8. Percent passing #200={(1)-(2)}/(1).times.100=%
Fines. Percent retained on #200={(2)-(3)}/(1).times.100=% Good.
Percent retained on #50={(3)-(4)}/(1).times.100=% Good. Percent
retained on #14={(4)-(5)}/(1).times.100=% Nits (fiber
agglomerates). Percent retained on #8=(5)/(1).times.100=% Pieces.
Percent passing #200 is reported as Fines. Percent retained on #200
screen, but passing #50 is reported as Good. Percent retained on
#50, but passing #14 is reported as Good. (Total Good is sum of the
two good fractions). Percent retained on #14 screen, but passing #8
screen is reported as Nits (fiber agglomerates). Percent retained
on #8 screen is reported as Pieces. It is recommended to run a
minimum of three tests per sample.
[0088] Scan Absorption Test can determine absorption properties
(Shred Absorption, sometimes called Absorption Capacity) of fluff
pulp pads. The method is based on the Scandinavian standard SCAN-C
33:80, the entire contents of which are hereby incorporated by
reference. Fluff volume (bulk), absorption rate and absorption
capacity are measured by placing a test pad on the unit, applying a
uniform load and allowing the pad to absorb liquid from below until
saturated. The apparatus is a SCAN Absorption Tester, which
includes a test piece former, absorption unit, and timing device.
Reagents include 0.9% saline (NaCl) solution. Procedure: (1)
Prepare saline solution, 0.9% sodium chloride in DI water (e.g.,
180 g/20 L) and transfer to saline delivery carboy; (2) Rinse
electrode platen and blot dry with wipe; rinse screen and reservoir
to remove residue, dry and replace in tester. Open valve on carboy
and run saline through until it flows into overflow pail; Close
valve; If necessary, stabilize the instrument by running a few
samples before analyzing test samples; (3) Mix fluff by vigorously
shaking inflated sample bag; Weigh out approximately 3.20 g of
fluff pulp (take several small portions throughout the bag to get a
representative sample); (4) Tare the forming tube (the plexiglass
cylindrical mold with 50 mm base screen) and place securely on pad
former (make sure it's firmly seated on gasket); Turn on vacuum and
feed the pulp into the former in small amounts, allowing fibers to
separate as much as possible; Avoid feeding in clumps of pulp; (5)
After pad has been formed turn off vacuum and remove mold/screen
assembly; Place tared assembly with pad on balance and remove
excess pulp to give a final weight of 3.00 g+/-0.01; Arrange pulp
as needed to give uniform thickness; Fibers sometimes build up on
one side in tube, especially if high in nits; Remove from this area
first to get the 3.00 g, then rearrange as needed, carefully
lifting mat/fibers to the thinner area; Gently tamp down the moved
fibers to give a uniform thickness; Prepare 6-8 pads per sample;
(6) Sample wt 3.00 g; (7) Pre-wet the SCAN tester sample basket and
use wipe to remove excess; Lower the electrode platen and zero
height sensor; Raise and latch the electrode platen; (8) Remove
bottom screen from forming tube; Place plexi tube on the SCAN wire
basket; gently lower the electrode platen (with the load on top of
shaft) onto the pad; carefully raise the mold (hold in place);
start timer then swing holder over and rest the tube on it; Avoid
touching the wires and shaft with the tube; start the saline flow
at about 18-20 seconds; at 30 sec, raise the reservoir in one even
motion, and hold in place; When prompted, lower the reservoir,
close the saline valve and allow pad to drain; When prompted, raise
the electrode platen up through the former tube; If pad sticks to
the platen, gently tap with edge of tube to release pad onto the
basket; Latch the electrode platen, remove forming tube and
carefully transfer pad to a balance; Record wet weight; Enter wet
pad weight in computer; Record the dry height (caliper, m),
specific volume (cc/g), absorption time (sec) and wet weight on
spreadsheet; Report absorption time (sec), absorption rate
(cm/sec), specific volume (g/cc), and capacity (g/g); Run 6-10
tests per sample; Report averages and SD.
[0089] Multi-Dose Acquisition Test Procedure: A 5''.times.12'' air
laid shredded fluff pulp sample is compressed to a density of 0.15
gms/cm.sup.3; A sheet of coverstock is placed on top of the
compressed sample; A 1'' diameter dosing tube weighing 1000 g is
centered on top of the sample; 30 mls of 0.9% saline solution is
dosed at a flow rate of 7 mls/sec; Timing begins once the dosage
started and ended when all of the saline solution is absorbed and
the absorption time is recorded; After 300 seconds after the first
dose is absorbed a second dose of saline solution is applied and
the timing procedure is repeated and the absorption time recorded;
300 seconds after the second dose is absorbed a third dose is
applied and the timing procedure is repeated and the absorption
time recorded.
[0090] Multi-Dose Rewet Test Procedure/Two Dose Rewet: A
5''.times.12'' air laid shredded fluff pulp sample is compressed to
a density of 0.15 gms/cm.sup.3; A sheet of coverstock is placed on
top of the compressed sample; A 1'' diameter dosing tube weighing
1000 g is centered on top of the sample; 30 mls. of 0.9% saline
solution was dosed at a flow rate of 7 mls/sec; After 300 seconds a
second dose of saline solution is applied; 300 seconds after the
second dose the dosing tube is removed and a recorded preweighed
8''.times.8'' sheet of Verigood blotter paper is placed on top and
a 50 cm2 3 kpa load is applied for 60 seconds; The load is removed
and the blotter paper is weighed. The difference between the wet
and dry paper is recorded as rewet.
[0091] SAP Retention Procedure: Produce fluffed pulp by fiberizing
sheets in a Kamas H 01 hammermill at specified conditions. Form 1.9
g pads as follows: Insert 14 mm screen in hammermill. Set the rotor
to .about.800 rpm. Place a carrier piece of non-woven material on
the 50 in.sup.2 forming screen and secure screen to funnel and
install in vacuum chamber. Weigh out .about.1.9 g fluffed pulp in a
weighing dish. Weigh out the desired % SAP for the test. Sprinkle
the SAP evenly over the fluff. Start the rotor and feed all the
pulp at once into the shredder through the front chute. Stop the
rotor and remove the funnel apparatus from bottom chamber. Use a
tamping device to compress pulp onto the forming screen. Remove top
funnel Remove pad and non-woven carrier together. Fold the
non-woven over the top of pad. Place the press ring on the nylon
block. Put the pad inside ring bottom down and place the rod inside
ring. Put 1000 g weight on rod and place in carver press. Press to
1000 psi and release pressure. Set sonic sifter at a 2 amplitude.
Prepare the sieve stack with the 60 mesh screen on top and 400 mesh
screen on bottom. Remove pad from non-woven and place on 60 mesh
sieve. Place stack into sifter. Set timer to three minutes and
press start. Collect and weigh SAP from the non-woven, 60 and 400
sieves. Calculate SAP retained.
[0092] Compressibility Procedure: Compressibility was tested on 900
gsm airlaid pads. Pads are made by forming 9 grams of conditioned
(50% relative humidity, 77 F) fiberized fluff pulp onto a 100
cm.sup.2 circular forming plate. The airlaid pads are then placed
into a 100 cm.sup.2 ring and a cylinder was placed on top of the
pad. The pad, ring and cylinder was placed under a Carver press and
a predetermined pressure load (to be specified by scientist) (in
Example 2 below, the predetermined pressure load was 161 and 225,
respectively) was applied for 1 minute. Afterwards, the pressure
was released and the compressed pad removed from the ring. 20
minutes later the thickness of the pad was measured and the pad
density calculated.
[0093] Gurley Stiffness Procedure: The Gurley Stiffness measurement
procedure is conducted in accordance with the procedure outlined
below using procedure T 543 Bending resistance of paper (Gurley
Type Tester).
EXAMPLES
Example 1
[0094] Four fluff pulps were prepared on a paper machine as
described herein, which contained different levels of hardwood
fiber. The four fluff pulps contained 0%, 8%, 15%, and 23% by
weight hardwood fibers. These fluff pulps were characterized for
their fluff pulp properties as well as fluff quality as described
within. The ability to retain SAP in a densified air laid core of
fluff pulp was also measured, as described herein.
[0095] FIG. 1 shows SAP retention of exemplary and comparative
embodiments.
[0096] FIG. 2 shows mullen values of exemplary and comparative
embodiments.
[0097] FIG. 3 shows shred energy values of exemplary and
comparative embodiments.
[0098] FIG. 4 shows shred quality in percent goods and fines for
exemplary and comparative embodiments.
[0099] FIG. 5 shows shred quality in percent nits and pieces for
exemplary and comparative embodiments.
[0100] FIG. 6 shows shred absorption in absorption capacity and
rate for exemplary and comparative embodiments.
[0101] Table 1 shows multi-dose acquisition test data for exemplary
and comparative embodiments.
TABLE-US-00001 TABLE 1 MULTI-DOSE ACQUISITION TEST - Acquisition
Times, seconds % HARDWOOD FIRST DOSE SECOND DOSE THIRD DOSE 0 27.4
74.4 98.0 8 33.2 88.3 115.3 15 37.3 99.7 127.4 34 40.8 110.1
135.1
[0102] Table 2 shows multi-dose rewet test data for exemplary and
comparative embodiments.
TABLE-US-00002 TABLE 2 MULTI-DOSE Rewet Test - Rewet Weight %
HARDWOOD SECOND DOSE THIRD DOSE 0 5.5 7.0 8 5.3 6.1 15 5.6 6.8 34
5.3 6.6
[0103] The results show that adding as little as 8% hardwood gave a
significant improvement in SAP retention
[0104] The results show that Mullen and Shred Energy are reduced
with hardwood substitution
[0105] The results show that shred quality is maintained, with
increased amount of fines in shred
[0106] The results show that acquisition rate increased with
hardwood, but rewet was unaffected.
[0107] These results suggest that a small hardwood substitution can
provide the benefits of making cores with high SAP content and
improved SAP retention, and thinner cores are possible.
[0108] From the results shown, it is clear that the examples
falling within the scope of the claims inhere superior benefits
when compared to those comparative examples.
Example 2
For these Examples a "Pad" May be a Core in an Absorbent
Article
[0109] Two fluff pulps were manufactured on a pulp machine in the
Southeastern US. One fluff pulp was made with 100% softwood fibers
(Control) while another fluff pulp as made with 82% softwood fibers
and 18% hardwood fibers (18% Hardwood). These fluff pulps were
fiberized on a 10 inch hammermill operating at 3000 rpm and a
federate of 0.24 kg/min/in width. Samples of the fiberized fluff
pulps were collected and made into airlaid pads that were typical
of pads used in the absorbent core of absorbent products. These
pads were tested for compressibility and stiffness.
[0110] Compressibility was tested on 900 gsm airlaid pads. These
pads were made by forming 9 grams of conditioned (50% relative
humidity, 77 F) fiberized fluff pulp onto a 100 cm.sup.2 circular
forming plate. The airlaid pads were then placed into a 100
cm.sup.2 ring and a cylinder was placed on top of the pad. The pad,
ring and cylinder was placed under a Carver press and a
predetermined load (as set forth in Table 3 below) was applied for
1 minute. Afterwards, the pressure was released and the compressed
pad removed from the ring. 20 minutes later the thickness of the
pad was measured and the pad density calculated. The results are
shown in Table
TABLE-US-00003 TABLE 3 Pressure on Pad Pad Thickness Pad Density
Fluff Pulp PSI mil g/cm3 Control 161 287 0.13 18% Hardwood 161 219
0.16 Control 225 205 0.18 18% Hardwood 225 160 0.22
[0111] The results in Table 3 clearly show that the fluff pulp
containing 18% hardwood was compressed to a thinner pad and higher
density than the control. Fluff pulp that compresses to a thinner
pad is a desirable characteristic for producers of absorbent
products as there is a need to make thinner absorbent products.
[0112] Making thinner products by increasing the density, however,
will result in an undesirable increase in the stiffness of the pad.
This stiffer pad will be uncomfortable to the user of the absorbent
product so there is a need to make a pad that is thinner yet
flexible and soft. Pads were made with the Control and 18% Hardwood
fluff pulps and their stiffness measured using a Gurley-type tester
to measure the bending resistance of these pads (see Tappi
procedure T 543 Bending resistance of paper). Pads were made at 300
gsm and compressed to various densities using different pressures
in the Carver press. A 1.5 inches by 1.0 inch piece was cut out of
the circular pad and placed into the Gurley stiffness tester. The
results are summarized in Table 4. In addition, a slightly treated
commercially produced fluff pulp (ST 160) was also included in this
analysis. The slightly treated fluff pulp is made by adding a small
about of debonder (<1 lb/T) to the stock approach system in the
wet end of the pulp machine. Debonders are typically added to fluff
pulps to reduce the amount of energy required to fiberize fluff
pulp and also to improve the shred quality of the fiberized fluff
pulp. This fluff pulp was made with 100% softwood fibers from the
southeastern US.
TABLE-US-00004 TABLE 4 Pad Density Gurley Stiffness Fluff Pulp
g/cm3 mg Control 0.12 760 Control 0.31 1383 Control 0.34 2534
Control 0.62 6822 18% Hardwood 0.14 825 18% Hardwood 0.31 1184 18%
Hardwood 0.35 1806 18% Hardwood 0.62 5808 ST160 - Slightly Treated
0.11 799 ST160 - Slightly Treated 0.22 947 ST160 - Slightly Treated
0.36 1458 ST160 - Slightly Treated 0.56 1287
[0113] These results clearly show that at a given density and
thickness (since these pads were made at the same basis weight) the
stiffness of the pads made with 18% Hardwood are less than the
Control made with 100% Softwood fibers. These results favorably
show an additional advantage of adding some hardwood to fluff pulp;
not only will adding hardwood allow for a thinner and a higher
density pad but it will also reduce the stiffness of the pad at a
given density which is desirable by producers of absorbent products
that want to make thinner products that are flexible and soft.
[0114] The results in Table 4 also clearly show the dramatic effect
that debonder has on the stiffness. The fluff pulp containing
debonder only slightly increased stiffness as the density was
increased. At the highest densities there is a very big difference
in the stiffness of these pads. Accordingly, the present inventors
have further discovered one embodiment of the this invention which
is that, by combining the effects of hardwood fibers and debonder
(or otherwise debonded fibers), a highly desirable fluff pulp could
be produced for an absorbent product producer requiring compressed
flexible webs, cores, pads, etc.
[0115] As used throughout, ranges are used as a short hand for
describing each and every value that is within the range, including
all subranges therein.
[0116] All other references, as well as their cited references,
cited herein are hereby incorporated by reference with respect to
relative portions related to the subject matter of the present
invention and all of its embodiments.
[0117] Numerous modifications and variations on the present
invention are possible in light of the above teachings. It is,
therefore, to be understood that within the scope of the
accompanying claims, the invention may be practiced otherwise than
as specifically described herein.
* * * * *