U.S. patent application number 15/447843 was filed with the patent office on 2017-09-28 for process for producing strong and soft tissue and towel products.
The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to Dale Gary KAVALEW, Osman POLAT.
Application Number | 20170275820 15/447843 |
Document ID | / |
Family ID | 58489433 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170275820 |
Kind Code |
A1 |
POLAT; Osman ; et
al. |
September 28, 2017 |
PROCESS FOR PRODUCING STRONG AND SOFT TISSUE AND TOWEL PRODUCTS
Abstract
A process for manufacturing a web material is disclosed. The
process generally provides the steps of: a. providing a pulp
material comprising fibers and vessels; b. separating said vessels
from said fibers in said pulp material to form a slurry having at
least about 7 percent less vessels per meter than said pulp
material; and c. processing said slurry to form said web
material.
Inventors: |
POLAT; Osman; (Montgomery,
OH) ; KAVALEW; Dale Gary; (Evendale, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Family ID: |
58489433 |
Appl. No.: |
15/447843 |
Filed: |
March 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62312487 |
Mar 24, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D21D 99/00 20130101;
D21B 1/026 20130101; D21D 5/24 20130101; D21F 11/14 20130101 |
International
Class: |
D21D 5/24 20060101
D21D005/24; D21B 1/02 20060101 D21B001/02 |
Claims
1. A process for manufacturing a web material, the process
comprising the steps of: a) providing a pulp material comprising
fibers and vessels; b) separating said vessels from said fibers in
said pulp material to form a slurry having at least about 7 percent
less vessels per meter than said pulp material; c) processing said
slurry to form said web material.
2. The process of claim 1 further comprising the step of separating
said vessels from said fibers with a hydrocyclone.
3. The process of claim 1 wherein said step b) further comprises
the step of creating an accepts stream and a rejects stream, said
accepts stream having less vessels than said rejects stream.
4. The process of claim 3 further comprising the step of separating
said vessels from said fibers in said rejects stream to form a
slurry having at least about 7 percent less vessels than said
rejects stream.
5. The process of claim 3 further comprising the step of processing
said rejects stream to create a second accepts stream and a second
rejects stream, said second accepts stream having less vessels than
said second rejects stream.
6. The process of claim 5 further comprising the step of adding
said second accepts stream to said slurry.
7. The process of claim 1 wherein said step c) further comprises
the step of depositing said slurry on a foraminous forming
wire.
8. The process of claim 7 further comprising the step of dewatering
said slurry disposed upon said foraminous forming wire to a fiber
consistency ranging from about 40 percent to about 80 percent.
9. The process of claim 8 further comprising the step of
transferring said dewatered slurry to a foraminous forming
member.
10. The process of claim 9 further comprising the step of
dewatering said slurry disposed upon said foraminous forming
member.
11. The process of claim 10 further comprising the step of
transferring said dewatered slurry from said foraminous forming
member to a surface of a through air dryer.
12. The process of claim 11 further comprising the step of creping
said dewatered slurry from said surface of said through air dryer
to form said web material.
13. The process of claim 12 further comprising the step of winding
said web material.
14. A process for manufacturing a papermaking slurry, said process
comprising the steps of: a. providing a pulp material comprising
fibers and vessels; b. separating said vessels from said fibers in
said pulp material to form said papermaking slurry having at least
about 7 percent less vessels per meter than said pulp material.
15. The process of claim 14 wherein said step b) further comprises
the step of separating said vessels from said fibers with a
hydrocyclone.
16. The process of claim 14 wherein said step of separating said
vessels from said fibers in said pulp material further comprises
the step of creating accepts stream and a rejects stream, said
accepts stream having less vessels than said rejects stream.
17. The process of claim 16 further comprising the step of
separating said vessels from said fibers in said rejects stream to
form a slurry having at least about 7 percent less vessels than
said rejects stream.
18. A process for manufacturing a papermaking slurry, said process
comprising the steps of: a. providing a pulp material comprising
fibers; b. separating fibers having an average width of at less
than about 50 .mu.M from said pulp material; c. forming said
papermaking slurry from said separated fibers.
19. The process of claim 18 wherein said step b) further comprising
the step of separating said fibers with a hydrocyclone.
20. The process of claim 19 wherein said step of separating said
fibers with a hydrocyclone further comprises the step of creating
accepts stream and a rejects stream, said accepts stream having
more fibers having an average width of at less than about 50 .mu.M.
Description
FIELD OF THE INVENTION
[0001] The present disclosure generally relates to processes for
producing cellulose pulps. More specifically, the present
disclosure relates to processes for producing cellulose pulps that
produce consumer tissue and towel products that have an increased
softness and strength.
BACKGROUND OF THE INVENTION
[0002] A vessel, vessel element, or vessel member is one of the
cell types found in xylem. Xylem is the tissue in vascular plants
which conducts water (and substances dissolved in it) upwards in a
plant. In a live tree, vessels serve as the pipelines within the
trunk, transporting sap within the tree. Conversely, softwoods
completely lack vessels, and instead rely on tracheids for sap
conduction. Vessel elements are the largest type of cells, and
unlike the other hardwood cell types, they can be viewed
individually--oftentimes even without any sort of magnification.
Vessel elements are the building blocks of vessels, which
constitute the major part of the water transporting system in those
plants in which they occur. Vessels form an efficient system for
transporting water (including necessary minerals) from the root to
the leaves and other parts of the plant.
[0003] Cellulose pulps that contain hardwood pulp fibers that
include vessels are used to produce consumer tissue or towel
products. Consumer tissue and towel products made from these pulp
fibers that offer both improved strength and increased softness are
in increasing demand. However, the known strength/softness dynamic
provides that as the tissue or towel product intrinsic strength
increases, the overall softness decreases. In other words, the
stronger you make a consumer tissue or towel product, the harder
and more rigid (and the less soft) it becomes.
[0004] Further, as the world's supply of native softwood fibers
become increasingly scarcer and more expensive, it has become
necessary to consider lower cost, and more abundant, sources of
cellulose to make paper products. This has caused a broader
interest in papermaking with traditionally lower quality sources of
fiber such as high lignin-content fibers and hardwood fibers, as
well as fibers from recycled paper. Unfortunately, these sources of
fiber often result in the comparatively severe deterioration of the
strength characteristics of paper compared to conventional virgin
chemical pulp furnishes.
[0005] Because of the above-mentioned reasons, pulps and processing
methods of increasing the intrinsic sheet strength and the
intrinsic sheet softness of consumer tissue and towel products
produced by fibrous pulps are of great interest.
[0006] One method described herein can be used for the centrifugal
separation of fibers having different apparent specific gravities
(e.g., by classifying fibers by width). The resulting fractions can
yield a pulp that can be used to produce a web product that has
higher wet tensile and a higher overall softness than currently
available products. In other words, it would be desirable to
provide a cellulose pulp that produces a consumer relevant tissue
or towel product that offers a higher level of wet tensile strength
and a higher level of softness. Such a product would fly in the
face of the known strength vs. softness dynamic and provide a
consumer with a more enjoyable user experience.
SUMMARY OF THE INVENTION
[0007] The present disclosure provides a process for manufacturing
a web material. The process generally comprises the steps of: a.
providing a pulp material comprising fibers and vessels; b.
separating the vessels from the fibers in said pulp material to
form a slurry having at least about 7 percent less vessels per ton
than said pulp material; and, c. processing the slurry to form the
web material.
[0008] The present disclosure also provides a process for
manufacturing a papermaking slurry. The process comprises the steps
of: a. providing a pulp material comprising fibers and vessels;
and, b. separating the vessels from the fibers in the pulp material
to form the papermaking slurry having at least about 7 percent less
vessels per meter than said pulp material.
[0009] The present disclosure further provides a process for
manufacturing a papermaking slurry. The process comprises the steps
of: a. providing a pulp material comprising fibers; b. separating
fibers having an average width of at less than about 50 .mu.M from
the pulp material; and, c. forming the papermaking slurry from the
separated fibers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a photomicrograph of a portion of an exemplary
Eucalyptus pulp material showing straight fibers and vessels;
[0011] FIG. 2 is a photomicrograph of a portion of an exemplary
Eucalyptus pulp material first stage fractionation "accept" stream
showing a reduced presence of Eucalyptus vessels;
[0012] FIG. 3 is a photomicrograph of a portion of an exemplary
Eucalyptus pulp material first stage fractionation "reject" stream
showing an increased presence of Eucalyptus vessels;
[0013] FIG. 4 is a photomicrograph of a portion of an exemplary
Eucalyptus pulp material second stage fractionation "accept" stream
showing a reduced presence of Eucalyptus vessels;
[0014] FIG. 5 is a photomicrograph of a portion of an exemplary
Eucalyptus pulp material second stage fractionation "reject" stream
showing an increased presence of Eucalyptus vessels;
[0015] FIG. 6 is a flow diagram of an exemplary 1-stage
fractionation process;
[0016] FIG. 7 is a flow diagram of an exemplary 2-stage
fractionation process;
[0017] FIG. 7A is a flow diagram of another exemplary 2-stage
fractionation process;
[0018] FIG. 8 is a schematic diagram of an exemplary papermaking
process suitable for producing consumer tissue and towel products
having increased strength and softness and manufactured with a pulp
having a reduced number of "vessels";
[0019] FIG. 9 is a photomicrograph showing a prior art consumer
product showing both vessels and non-vessel fiber elements;
and,
[0020] FIG. 10 is a photomicrograph showing a consumer product
produced by the process of the present disclosure having reduced
vessel element content, increased strength, and softness;
[0021] FIG. 11 is a schematic representation of an exemplary 2-ply
web material where each ply is formed from a layer of Eucalyptus
feed pulp fibers and a layer of a mixture comprising a blend of
Eucalyptus feed pulp fibers and northern softwood kraft (NSK)
fibers;
[0022] FIG. 12 is a schematic representation of another exemplary
2-ply web material where each ply is formed from a layer of the
"accept" fraction from hydrocyclonically treated Eucalyptus feed
pulp fibers and a layer comprising a mixture of Eucalyptus feed
pulp fibers and NSK fibers;
[0023] FIG. 13 is a schematic representation of yet another
exemplary 2-ply web material where each ply is formed from a layer
of the "accept" fraction from hydrocyclonically treated Eucalyptus
feed pulp fibers and a layer comprising a mixture of the "reject"
fraction from hydrocyclonically treated Eucalyptus feed pulp fibers
and NSK fibers;
[0024] FIG. 14 is a schematic representation of still yet another
exemplary 2-ply web material where each ply is formed from a layer
of the "accept" fraction from hydrocyclonically treated Eucalyptus
feed pulp fibers at a different pressure and a layer comprising a
mixture of Eucalyptus feed pulp fibers and NSK fibers;
[0025] FIG. 15 is a graphical representation of the relationship
between wet tensile modulus (in g/cm) and dry tensile modulus (in
g/cm) for various 1-ply commercially available substrates and the
substrates produced by the process described herein; and,
[0026] FIG. 16 is a graphical representation of the relationship
between wet tensile modulus (in g/cm) and dry tensile modulus (in
g/cm) for various 2-ply commercially available substrates and the
substrates produced by the process described herein.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Briefly, the present disclosure relates to a cellulose
pulp-making process that provides improved levels of strength and
softness in fibrous structures and/or sanitary tissue product
produced by the pulp so processed. Heretofore unachievable levels
of strength and softness are made possible by selecting fibers of
preferred morphology from cellulose pulp sources by the process
described herein.
[0028] "Fractionation" as used herein is a screening process in
which fibrous papermaking pulp slurry is separated into at least
two fractions of fibers having different fiber widths. Several
methods to segregate fibers by width are envisioned. While not
intended to be construed as limiting the present invention to a
certain set of process steps, the following illustrates several
methods of preparing cellulose pulps that can comply according to
the specifications of the present disclosure. These include methods
of fractionating fibers by a combination of size and shape. Also
included are certain methods employing a mechanical pre-treatment
step, before fractionating the fibers, according to size and
shape.
[0029] The first utilizes a process for separating fibers by the
use of a hydraulic cyclone. Generally, a fibrous pulp slurry is
charged to a cyclone and separated into a slurry fraction that
contains fibers having a lower average width and a slurry fraction
that contains fibers of higher average width.
[0030] The second fractionation process also provides two fractions
of fibers having different fiber width. A fibrous pulp slurry is
directed toward an apertured screen. A slurry fraction containing
fibers having a lower width passes through the apertures and a
slurry fraction containing fibers having a higher average width are
retained by the screening process.
[0031] In any regard, quantities of water are required for forming
the slurries at each stage of the process. Since water reuse would
normally be desired in any of the process methods, a water
clarifier working on the principal of injecting air to create air
bubbles which attach to solid particles and cause them to rise to
the surface where they may be collected. This can leave
substantially solids-free water which can be reused to create the
pulp slurries.
[0032] As used herein, the term "morphology" refers to the various
physical forms of wood fibers including such characteristics as
fiber type, fiber length, fiber width, cell wall thicknesses,
coarseness, and similar characteristics, determined both on the
basis of bulk average properties as well as on a local or
distributive basis. The term "selected morphology" refers to fibers
which have been selected from the general class of fibers to
provide enhanced performance with regard to tensile strength and
softness.
[0033] The term "tensile strength" refers to the tensile strength
of the substrates made from the pulps as described below.
Preferably, the tensile strength potential of pulps of the present
invention is from about 200 Win to about 4000 Win, or from about
300 to about 2500 Win, or from about 400 Win to about 900 Win.
[0034] As used herein, "softness" is a subjective property of a web
substrate (e.g. bath tissue) that can be measured by a sensory
panel of selected consumers brought to a central location for
conducting the tests or by consumers carrying out a home use test
where products are given to them to use and their perceptions are
recorded by means of a questionnaire
[0035] "Vessels" are composed of single cells. Their size and
distribution within the growth ring of the tree vary according to
the species. Vessel elements are shorter than hardwood fibers, and
the diameter of vessels varies greatly from species to species. In
general, there is about 3 to 25 vessels/mm.sup.2 of eucalyptus
xylem cross section. Some species have more vessels than others.
There is also much variation between the dimensions of vessel
elements, but have mostly a diameter ranging from 60 .mu.m to 250
.mu.m and a length between 200 .mu.m to 600 .mu.m. Species rich in
wide diameter vessels may reach approximately 25% to 30% of its
volume in vessels. In most commercial eucalyptus species, the
proportion of vessels by volume can range from 10% to 20%.
[0036] A vessel wall is relatively thin, practically equal to the
fiber wall thickness, and can range between 2.5 .mu.m and 5 .mu.m.
The chemical composition of the vessels is similar to that of the
fiber in its chemical constituents, but there are some differences
between fibers and vessels. Vessel elements have been found to be
richer in cellulose compared with fibers, and lignin has been found
in vessel elements even after bleaching. There are also indications
that the lignin in vessels is more hydrophobic, richer in guaiacyl
units than in syringyl. The syringyl to guaiacyl ratio may reach
about 0.5 to 1 for the vessels, while that of fibers is from 2 to
6. It was also found that the xylan content of vessel elements is
higher than that of the fibers.
Process
[0037] The process of the present disclosure provides for the
width-wise fractionation of mill dried pulps. These exemplary mill
dried pulps were allowed to swell overnight and disintegrated using
a 50-liter disintegrator the next morning. The disintegration time
was 15 minutes with a pulp consistency about 5%. The exemplary
pulps were fractionated using a 3'' hydrocyclone. Trials were
performed with feed pulp consistency of 0.1% and differential
pressure was 1.6 bar. The trial configuration for Eucalyptus
globulus is shown in FIG. 7A. As referenced herein, the untreated
eucalyptus pulp fed to the hydrocyclone is called "feed pulp", the
vessel-poor pulp fraction is referenced as the "accept pulp" or
"accepts", and the vessel-rich pulp fraction is referenced as the
"reject pulp" or "rejects".
[0038] FIG. 1 is a photomicrograph of an exemplary Eucalyptus fiber
feed pulp 10 showing both fibers 12 and vessels 14. As can be seen,
there are numerous vessels 14 distributed throughout the fiber feed
pulp 10 and intermixed with the fibers 12.
[0039] FIG. 2 depicts an exemplary photomicrograph of an accept
pulp product 10A showing an increased percentage of fibers 12
relative to the number of vessels 14. In short, the single-stage
fractionation process resulted in a marked decrease in the number
of vessels 14 per ton of fiber feed pulp 10. The percentage of
vessels/meter of the feed pulp decreased from about 7%/meter to
about 5%/meter to provide the accept pulp product 10A as determined
by the Pulp Fiber and Vessel Measurement Method (Fiber Quality
Analysis) provided infra. One of skill in the art could extrapolate
this data to also provide a decrease in the percentage of
vessels/meter of the feed pulp from about 7%/ton to about 5%/ton to
provide the accept pulp product 10A.
[0040] Table 1 provides relevant data based upon the analysis of
the various pulp streams of the fractionation process using a
Beloit Posiflow Cleaner with a smooth-tapered tip. This includes
the feed pulp 10 stream (e.g., Eucalyptus raw pulp fibers), fiber
12 stream (i.e., accepts), and vessel 14 stream (i.e., rejects). As
can be seen from the data presented, the average fiber 12 stream
(i.e., accepts) shows a decrease in vessel 14 content of about 6
percent. Additionally, the data indicates that the average vessel
14 content in the vessel 14 stream (i.e., rejects) increases about
250 percent.
TABLE-US-00001 TABLE 1 Relevant data relative to the
hydro-cycloning of Eucalyptus pulp as analyzed by Fiber Quality
Analyzer Mean Vessel Vessels/ Vessels/ Mean fiber Effective Sample
ID meter gram width, .mu.M Width, .mu.M Base Euc #1 6.21 110967
18.2 123.1 Base Euc #2 5.80 103521 17.7 111.5 Base Euc #3 6.42
114620 119.0 Accepts #1 5.73 104178 17.2 111.1 Accepts #2 5.82
105738 17.3 112.9 Accepts #3 5.40 98244 116.7 Rejects #1 15.20
245180 17.4 120.9 Rejects #2 19.07 307594 18.2 122.2 Rejects #3
16.70 269374 125.0
[0041] Exemplary fractionation results from the fractionation of
Eucalyptus feed pulp at different process conditions are provided
in Table 4 infra.
[0042] Contrastingly, FIG. 3 depicts an exemplary photomicrograph
of a reject stream pulp product 10B showing an increased percentage
of vessels 14 relative to the number of fibers 12. In short, the
single-stage fractionation process resulted in a marked increase in
the number of vessels/ton of feed pulp material. The percentage of
vessels/meter of pulp increased from about 7%/meter to about
15%/meter as determined by the Pulp Fiber and Vessel Measurement
Method (Fiber Quality Analysis) provided infra. One of skill in the
art could extrapolate this data to also provide an increase in the
percentage of vessels/meter of the feed pulp from about 7%/ton to
about 5%/ton to provide the accept pulp product 10A.
[0043] FIG. 4 provides a photomicrograph of an exemplary accept
stream product 10C yield from an exemplary 2-stage fractionation
process. As shown, the relative percentage of fibers 12 relative to
the number of vessels 14 increased. It should be noted that the
reject stream of FIG. 3 provided the feed pulp for the exemplary
2-stage process that produced the accept stream pulp.
[0044] Again, contrastingly, an exemplary reject stream product 10D
from the second stage of a 2-stage fractionation process shown in
FIG. 5 shows an increased amount of vessels 14 relative to the
number of fibers 12.
[0045] As shown in FIG. 6, Eucalyptus globulus hardwood feed pulp
31 can be treated by a fractionation process 20 in a single-stage
pulp fractionation system 22. Two product streams (i.e., first
product stream 23 and second product stream 25) are created by the
single-stage pulp fractionation system 22. The first product stream
23 results in accept product 24 having a lower percentage of
vessels 14 than the feed pulp 31. The second product stream 25
results in reject product 26 having a higher percentage of vessels
14 than the feed pulp 31.
[0046] As shown in FIG. 7, one of skill in the art will appreciate
that fractionation of Eucalyptus globulus hardwood feed pulp 31 can
also occur in a process 30 incorporating a two-stage system 32, 38.
Four product streams 33, 35, 37, 39 are created by the two-stage
pulp fractionation system 32, 38. Here, the first stage 32 creates
two product streams 33, 35. The first product stream 33 results in
accept product 33 having a lower percentage of vessels 14 than the
feed pulp 31. The second product stream 35 results in reject
product 36 having a higher percentage of vessels 14 than the feed
pulp 31. The second product stream 35 provides the input pulp
stream feed to the second stage 38. The second stage 38 provides a
third product stream 37 resulting in additional accept product 34
having a lower percentage of vessels 14 than the feed pulp. The
fourth product stream 39 results in additional reject product 36
having a higher percentage of vessels 14 than the feed pulp 31.
[0047] As shown in FIG. 7A, an alternative fractionation of
hardwood feed pulp 31 (such as Eucalyptus globulus) can also occur
in a process 30A incorporating a two-stage system 32, 38. Four
product streams 33A, 35, 37, 39 are created by the two-stage pulp
fractionation system 32, 38. Here, the first stage 32 creates two
product streams 33A, 35. The first product stream 33A can result in
accept product 34 having a lower percentage of vessels 14 than the
feed pulp 31. The second product stream 35 results in reject
product having a higher percentage of vessels 14 than the feed pulp
31. The second product stream 35 provides the input feed pulp
stream feed to the second stage 38. The second stage 38 provides a
third product stream 37 resulting in additional accept fibers 12
having a lower percentage of vessels 14 than the second product
stream 35. The fourth product stream 39 results in additional
reject product 36 having a higher percentage of vessels 14 than the
feed pulp 31. The third product stream 37 provides an additional
feed pulp to the input of first stage 32. This can result in the
increased amount of accept fibers 12 provided into first product
stream 33A.
[0048] In any regard, the accept pulp of each stage can be
recovered and saved. The reject pulp stream of any preceding stage
can then be fed to any successive stage. For example, the accept
pulp from the second stage can be recovered, combined with the
accept pulp of the first stage, and saved. One of skill in the art
will understand that the reject pulp stream of the first stage can
be fed to a second stage and the reject pulp stream of the second
stage can be fed to third stage, etc.
[0049] After each fractionation stage the pulp samples can be
analyzed with an OpTest Equipment, Inc. Fiber Quality Analyzer to
determine the number, length, and width of the respective fibers
and vessel elements to monitor separation efficiency, as well as
other fiber properties.
[0050] "Basis Weight" as used herein is the weight per unit area of
a sample reported in lbs/3000 ft.sup.2 or g/m.sup.2 (gsm) and is
measured according to the Basis Weight Test Method described
herein.
[0051] "Machine Direction" or "MD" as used herein means the
direction parallel to the flow of the fibrous structure through the
fibrous structure making machine and/or sanitary tissue product
manufacturing equipment.
[0052] "Cross Machine Direction" or "CD" as used herein means the
direction parallel to the width of the fibrous structure making
machine and/or sanitary tissue product manufacturing equipment and
perpendicular to the machine direction.
[0053] "Ply" as used herein means an individual, integral fibrous
structure.
[0054] "Plies" as used herein means two or more individual,
integral fibrous structures disposed in a substantially contiguous,
face-to-face relationship with one another, forming a multi-ply
fibrous structure and/or multi-ply sanitary tissue product. It is
also contemplated that an individual, integral fibrous structure
can effectively form a multi-ply fibrous structure, for example, by
being folded on itself.
[0055] "Differential density", as used herein, means fibrous
structures and/or sanitary tissue products that comprise one or
more regions of relatively low fiber density, which are referred to
as pillow regions, and one or more regions of relatively high fiber
density, which are referred to as knuckle regions.
[0056] "Densified", as used herein means a portion of a fibrous
structure and/or sanitary tissue product that is characterized by
regions of relatively high fiber density (i.e., knuckle
regions).
[0057] "Non-densified", as used herein, means a portion of a
fibrous structure and/or sanitary tissue product that exhibits a
lesser density (one or more regions of relatively lower fiber
density) (pillow regions) than another portion (for example a
knuckle region) of the fibrous structure and/or sanitary tissue
product.
[0058] "3D pattern" with respect to a fibrous structure and/or
sanitary tissue product's surface in accordance with the present
invention means herein a pattern that is present on at least one
surface of the fibrous structure and/or sanitary tissue product.
The 3D pattern texturizes the surface of the fibrous structure
and/or sanitary tissue product, for example by providing the
surface with protrusions and/or depressions. The 3D pattern on the
surface of the fibrous structure and/or sanitary tissue product can
be made by making the sanitary tissue product or at least one
fibrous structure ply employed in the sanitary tissue product on a
patterned molding member that imparts the 3D pattern to the
sanitary tissue products and/or fibrous structure plies made
thereon. For example, the 3D pattern may comprise a series of line
elements, such as a series of line elements that are substantially
oriented in the cross-machine direction of the fibrous structure
and/or sanitary tissue product. Additionally, a 3D pattern on the
surface of the fibrous structure and/or sanitary tissue product can
be made by embossing the sanitary tissue product by techniques
understood by one of skill in the art.
[0059] Referring again to FIGS. 6-7 and 7A, the accept pulp was
then utilized to form a papermaking slurry 50, 50A, 50B. The
enhanced pulps of the present invention are suitable for use in a
wide variety of papers and papermaking processes. The cellulose
pulps are particularly suitable for use in making papers having
densities of <0.15 g/cc. Papers having such low density (i.e.,
<0.15 g/cc) and low basis weight (i.e., <30 g/m.sup.2) are
especially suitable for use as tissue paper and paper towels.
[0060] One manner of forming a tissue and/or towel product of the
present disclosure incorporates the deposition of the papermaking
furnish having a baseline, increased, or reduced vessel number
content on a foraminous forming wire, often referred to in the art
as a Fourdrinier wire. From the time a furnish is deposited on the
forming wire, it is referred to as a "web material". In short, the
web material is dewatered by pressing the web and drying at
elevated temperature. In a typical process, a low consistency pulp
furnish is provided from a pressurized headbox. The headbox has an
opening for delivering a thin deposit of pulp furnish onto the
Fourdrinier wire to form a wet web. The web is then typically
dewatered to a fiber consistency of between about 7% and about 25%
(total web weight basis) by vacuum dewatering and further dried by
pressing operations. Preferably, the furnish is first formed into a
wet web on a foraminous forming carrier, such as a Fourdrinier
wire. The web is dewatered and transferred to an imprinting fabric.
The furnish can alternately be initially deposited on a foraminous
supporting carrier that also operates as an imprinting fabric. Once
formed, the wet web is dewatered and, preferably, thermally
pre-dried to a selected fiber consistency of between about 40% and
about 80%.
[0061] "Co-formed fibrous structure" as used herein means that the
fibrous structure comprises a mixture of at least two different
materials wherein at least one of the materials comprises a
filament, such as a polypropylene filament, and at least one other
material, different from the first material, comprises a solid
additive, such as a fiber and/or a particulate. In one example, a
co-formed fibrous structure comprises solid additives, such as
fibers, such as wood pulp fibers, and filaments, such as
polypropylene filaments.
[0062] "Fiber" and/or "Filament" as used herein means an elongate
particulate having an apparent length greatly exceeding its
apparent width, i.e. a length to diameter ratio of at least about
10. In one example, a "fiber" is an elongate particulate as
described above that exhibits a length of less than 5.08 cm (2 in.)
and a "filament" is an elongate particulate as described above that
exhibits a length of greater than or equal to 5.08 cm (2 in.).
[0063] Fibers are typically considered discontinuous in nature.
Non-limiting examples of fibers include pulp fibers, such as wood
pulp fibers, and synthetic staple fibers such as polyester
fibers.
[0064] Filaments are typically considered continuous or
substantially continuous in nature. Filaments are relatively longer
than fibers. Non-limiting examples of filaments include melt-blown
and/or spun-bond filaments. Non-limiting examples of materials that
can be spun into filaments include natural polymers, such as
starch, starch derivatives, cellulose and cellulose derivatives,
hemi-cellulose, hemi-cellulose derivatives, and synthetic polymers
including, but not limited to polyvinyl alcohol filaments and/or
polyvinyl alcohol derivative filaments, and thermoplastic polymer
filaments, such as polyesters, nylons, polyolefins such as
polypropylene filaments, polyethylene filaments, and biodegradable
or compostable thermoplastic fibers such as polylactic acid
filaments, polyhydroxyalkanoate filaments and polycaprolactone
filaments. The filaments may be mono-component or multi-component,
such as bi-component filaments.
[0065] In one example of the present invention, "fiber" refers to
papermaking fibers. Papermaking fibers useful in the present
invention include cellulosic fibers commonly known as wood pulp
fibers. Applicable wood pulps include chemical pulps, such as
Kraft, sulfite, and sulfate pulps, as well as mechanical pulps
including, for example, ground wood, thermomechanical pulp, and
chemically modified thermomechanical pulp. Chemical pulps, however,
may be preferred since they impart a superior tactile sense of
softness to tissue sheets made therefrom. Pulps derived from both
deciduous trees (hereinafter, also referred to as "hardwood") and
coniferous trees (hereinafter, also referred to as "softwood") may
be utilized. The hardwood and softwood fibers can be blended, or
alternatively, can be deposited in layers to provide a stratified
fibrous structure. Also applicable to the present invention are
fibers derived from recycled paper, which may contain any or all of
the above categories as well as other non-fibrous materials such as
fillers and adhesives used to facilitate the original
papermaking.
[0066] In one example, the wood pulp fibers are selected from the
group consisting of hardwood pulp fibers, softwood pulp fibers, and
mixtures thereof. The hardwood pulp fibers may be selected from the
group consisting of: tropical hardwood pulp fibers, northern
hardwood pulp fibers, and mixtures thereof. The tropical hardwood
pulp fibers may be selected from the group consisting of:
eucalyptus fibers, acacia fibers, and mixtures thereof. The
northern hardwood pulp fibers may be selected from the group
consisting of: aspen, balsam, poplar, maple fibers, and mixtures
thereof. In addition to the various wood pulp fibers, other
cellulosic fibers such as cotton linters, rayon, lyocell,
trichomes, seed hairs, and bagasse can be used. Other sources of
cellulose in the form of fibers or capable of being spun into
fibers include grasses and grain sources.
[0067] By way of example only, FIG. 8 provides an exemplary
embodiment of a continuous papermaking machine 100 that can be used
in practicing the process of the present invention. The process of
the present invention comprises a number of steps or operations
which occur in sequence. While the process of the present invention
is preferably carried out in a continuous fashion, it will be
understood that the present invention can comprise a batch
operation, such as a hand sheet making process. A preferred
sequence of steps will be described, with the understanding that
the scope of the present invention is determined with reference to
the appended claims.
[0068] According to one embodiment of the present invention, an
embryonic web 120 of papermaking fibers having certain measureable
physical properties such as basis weight, topography, caliper,
tension, fiber orientation, moisture content, MD and/or CD tensile
strength, and/or MD and/or CD web stretch, combinations thereof,
and the like, is formed from an aqueous dispersion of papermaking
fibers on a foraminous forming member 11. The embryonic web 120 is
then transferred to a foraminous imprinting member 219 having a
first web contacting face 220 comprising a web imprinting surface
and a deflection conduit portion. If desired, a portion of the
papermaking fibers in the embryonic web 120 can be deflected into
deflection conduit portion of the foraminous imprinting member 219
without densifying the web, thereby forming an intermediate web
120A.
[0069] The intermediate web 120A is carried on the foraminous
imprinting member 219 from the foraminous forming member 11 to a
compression nip 300 formed by opposed compression surfaces on first
and second nip rolls 322 and 362. A first dewatering felt 320 is
positioned adjacent the intermediate web 120A, and a second
dewatering felt 360 is positioned adjacent the foraminous
imprinting member 219. The intermediate web 120A and the foraminous
imprinting member 219 are then pressed between the first and second
dewatering felts 320 and 360 in the compression nip 300 to further
deflect a portion of the papermaking fibers into the deflection
conduit portion of the imprinting member 219; to densify a portion
of the intermediate web 120A associated with the web imprinting
surface; and to further dewater the web by removing water from both
sides of the web, thereby forming a molded web 120B which is
relatively dryer than the intermediate web 120A. One of skill in
the art will recognize that it is not necessary to include a step
of pressing the intermediate web 120A between the first and second
dewatering felts 320 and 360 in a compression nip.
[0070] The molded web 120B is carried from the compression nip 300
on the foraminous imprinting member 219. The molded web 120B can be
pre-dried in a through-air dryer 400 by directing heated air to
pass first through the molded web, and then through the foraminous
imprinting member 219, thereby further drying the molded web 120B.
The web imprinting surface of the foraminous imprinting member 219
can then be impressed into the molded web 120B such as at a nip
formed between a roll 209 and a dryer drum 510, thereby forming an
imprinted web 120C. Impressing the web imprinting surface into the
molded web can further densify the portions of the web associated
with the web imprinting surface. The imprinted web 120C can then be
dried on the dryer drum 510 (such as a Yankee dryer) and creped
from the dryer drum by a doctor blade 524.
[0071] Examining the process steps according to the present
invention in more detail, a first step in practicing the present
invention is providing an aqueous dispersion of papermaking fibers
derived from wood pulp to form the embryonic web 120. The
papermaking fibers utilized for the present invention will normally
include fibers derived from wood pulp. Other cellulosic fibrous
pulp fibers, such as cotton linters, bagasse, etc., can be utilized
and are intended to be within the scope of this invention.
Synthetic fibers, such as rayon, polyethylene, polyester, and
polypropylene fibers, may also be utilized in combination with
natural cellulosic fibers. One exemplary polyethylene fiber which
may be utilized is Pulpex.TM., available from Hercules, Inc.
(Wilmington, Del.). Applicable wood pulps include chemical pulps,
such as Kraft, sulfite, and sulfate pulps, as well as mechanical
pulps including, for example, ground wood, thermo-mechanical pulp
and chemically modified thermo-mechanical pulp. Pulps derived from
both deciduous trees (hereinafter, also referred to as "hardwood")
and coniferous trees (hereinafter, also referred to as "softwood")
may be utilized. Also applicable to the present invention are
fibers derived from recycled paper, which may contain any or all of
the above categories as well as other non-fibrous materials such as
fillers and adhesives used to facilitate the original
papermaking.
[0072] In addition to papermaking fibers, the papermaking furnish
used to make paper product structures may have other components or
materials added thereto as may be or later become known in the art.
The types of additives desirable will be dependent upon the
particular end use of the paper product sheet contemplated. For
example, in products such as toilet paper, paper towels, facial
tissues and other similar products, high wet strength is a
desirable attribute. Thus, it is often desirable to add to the
papermaking furnish chemical substances known in the art as "wet
strength" resins. It is to be understood that the addition of
chemical compounds such as the wet strength and temporary wet
strength resins discussed above to the pulp furnish is optional and
is not necessary for the practice of the present development.
[0073] The embryonic web 120 is preferably prepared from an aqueous
dispersion of the papermaking fibers, though dispersions of the
fibers in liquids other than water can be used. The fibers are
dispersed in water to form an aqueous dispersion having a
consistency of from about 0.1 to about 0.3 percent. The percent
consistency of dispersion, slurry, web, or other system is defined
as 100 times the quotient obtained when the weight of dry fiber in
the system under discussion is divided by the total weight of the
system. Fiber weight is always expressed on the basis of bone dry
fibers.
[0074] Referring again to FIG. 8, a second step in the practice of
the present invention is forming the embryonic web 120 of
papermaking fibers. An aqueous dispersion of papermaking fibers is
provided to a head box 18 which can be of any convenient design.
From the head box 18 the aqueous dispersion of papermaking fibers
is delivered to a foraminous forming member 11 to form an embryonic
web 120. The forming member 11 can comprise a continuous
Fourdrinier wire. Alternatively, the foraminous forming member 11
can comprise a plurality of polymeric protuberances joined to a
continuous reinforcing structure to provide an embryonic web 120
having two or more distinct basis weight regions, such as is
disclosed in U.S. Pat. No. 5,245,025. While a single forming member
11 is shown in FIG. 8, single or double wire forming apparatus may
be used. Other forming wire configurations, such as S or C wrap
configurations can be used.
[0075] The forming member 11 is supported by a breast roll 12 and
plurality of return rolls, of which only two return rolls 13 and 14
are shown in FIG. 8. The forming member 11 is driven in the
direction indicated by the arrow 81 by a drive means (not shown).
The embryonic web 120 is formed from the aqueous dispersion of
papermaking fibers by depositing the dispersion onto the foraminous
forming member 11 and removing a portion of the aqueous dispersing
medium. The embryonic web 120 has a first web face 122 contacting
the foraminous member 11 and a second oppositely facing web face
124.
[0076] The embryonic web 120 can be formed in a continuous
papermaking process, as shown in FIG. 8, or alternatively, a batch
process, such as a hand-sheet making process can be used. In any
regard, after the aqueous dispersion of papermaking fibers is
deposited onto the foraminous forming member 11, an embryonic web
120 is formed by removal of a portion of the aqueous dispersing
medium by techniques well known to those skilled in the art. Vacuum
boxes, forming boards, hydrofoils, and the like are useful in
effecting water removal from the aqueous dispersion on the
foraminous forming member 11. The embryonic web 120 travels with
the forming member 11 about the return roll 13 and brought into the
proximity of a foraminous imprinting member 219 described
infra.
[0077] A third step in the practice of the present invention
comprises transferring the embryonic web 120 from the foraminous
forming member 11 to the foraminous imprinting member 219, to
position the second web face 124 on the first web contacting face
220 of the foraminous imprinting member 219. Although the preferred
embodiment of the foraminous imprinting member 219 of the present
invention is in the form of an endless belt, it can be incorporated
into numerous other forms which include, for instance, stationary
plates for use in making hand sheets or rotating drums for use with
other types of continuous process. Regardless of the physical form
which the foraminous imprinting member 219 takes for the execution
of the claimed invention, it is generally provided with the
physical characteristics detailed infra.
[0078] A fourth step in the practice of the present invention
comprises deflecting a portion of the papermaking fibers in the
embryonic web 120 into the deflection conduit portion 230 of web
contacting face 220 of the foraminous imprinting member 219, and
removing water from the embryonic web 120 through the deflection
conduit portion 230 of the foraminous imprinting member 219 to form
an intermediate web 120A of the papermaking fibers. The embryonic
web 120 preferably has a consistency of between about 10 and about
20 percent at the point of transfer to facilitate deflection of the
papermaking fibers into the deflection conduit portion 230 of the
foraminous imprinting member 219.
[0079] The steps of transferring the embryonic web 120 to the
imprinting member 219 and deflecting a portion of the papermaking
fibers in the web 120 into the deflection conduit portion 230 of
the foraminous imprinting member 219 can be provided, at least in
part, by applying a differential fluid pressure to the embryonic
web 120. For instance, the embryonic web 120 can be vacuum
transferred from the forming member 11 to the imprinting member
219, such as by a vacuum box 126 shown in FIG. 8, or alternatively,
by a rotary pickup vacuum roll (not shown). The pressure
differential across the embryonic web 120 provided by the vacuum
source (e.g. the vacuum box 126) deflects the fibers into the
deflection conduit portion 230, and preferably removes water from
the web through the deflection conduit portion 230 to raise the
consistency of the web to between about 18 and about 30 percent.
The pressure differential across the embryonic web 120 can range
from between about 13.5 kPa and about 40.6 kPa (between about 4 to
about 12 inHg). The vacuum provided by the vacuum box 126 permits
transfer of the embryonic web 120 to the foraminous imprinting
member 219 (with or without a speed differential) and deflection of
the fibers into the deflection conduit portion 230 without
compacting the embryonic web 120. Additional vacuum boxes (not
shown) can be included to further dewater the intermediate web
120A.
[0080] A fifth step in the practice of the present invention
comprises pressing the wet intermediate web 120A in the compression
nip 300 to form the molded web 120B. Referring again to FIG. 8, the
intermediate web 120A is carried on the foraminous imprinting
member 219 from the foraminous forming member 11 and through the
compression nip 300 formed between opposed compression surfaces on
nip rolls 322 and 362. The first dewatering felt 320 is shown
supported in the compression nip by the nip roll 322 and driven in
the direction 321 around a plurality of felt support rolls 324.
Similarly, the second dewatering felt 360 is shown supported in the
compression nip 300 by the nip roll 362 and driven in the direction
361 around a plurality of felt support rolls 364. A felt dewatering
apparatus 370, such as an Uhle vacuum box can be associated with
each of the dewatering felts 320 and 360 to remove water
transferred to the dewatering felts from the intermediate web
120A.
[0081] The nip rolls 322 and 362 can have generally smooth opposed
compression surfaces, or alternatively, the rolls 322 and 362 can
be grooved. In an alternative embodiment (not shown) the nip rolls
can comprise vacuum rolls having perforated surfaces for
facilitating water removal from the intermediate web 120A. The
rolls 322 and 362 can have rubber coated opposed compression
surfaces, or alternatively, a rubber belt can be disposed
intermediate each nip roll and its associated dewatering felt. The
nip rolls 322 and 362 can comprise solid rolls having a smooth,
bone-hard rubber cover, or alternatively, one or both of the rolls
322 and 362 can comprise a grooved roll having a bone-hard rubber
cover.
[0082] The term "dewatering felt" as used herein refers to a member
that is absorbent, compressible, and flexible so that it is
deformable to follow the contour of the non-monoplanar intermediate
web 120A on the imprinting member 219, and capable of receiving and
containing water pressed from an intermediate web 120A. The
dewatering felts 320 and 360 can be formed of natural materials,
synthetic materials, or combinations thereof.
[0083] A preferred but non-limiting dewatering felt 320, 360 can
have a thickness of between about 2 mm to about 5 mm, a basis
weight of about 800 to about 2000 grams per square meter, an
average density (basis weight divided by thickness) of between
about 0.35 gram per cubic centimeter and about 0.45 gram per cubic
centimeter, and an air permeability of between about 15 and about
110 cubic feet per minute per square foot, at a pressure
differential across the dewatering felt thickness of 0.12 kPa (0.5
inch of water). The dewatering felt 320 preferably has first
surface 325 having a relatively high density, relatively small pore
size, and a second surface 327 having a relatively low density,
relatively large pore size. Likewise, the dewatering felt 360
preferably has a first surface 365 having a relatively high
density, relatively small pore size, and a second surface 367
having a relatively low density, relatively large pore size. The
relatively high density and relatively small pore size of the first
felt surfaces 325, 365 promote rapid acquisition of the water
pressed from the web in the nip 300. The relatively low density and
relatively large pore size of the second felt surfaces 327, 367
provide space within the dewatering felts for storing water pressed
from the web in the nip 300. Suitable dewatering felts 320 and 360
are commercially available as SUPERFINE DURAMESH, style XY31620
from the Albany International Company of Albany, N.Y.
[0084] The intermediate web 120A and the web imprinting surface 222
are positioned intermediate the first and second felt layers 320
and 360 in the compression nip 300. The first felt layer 320 is
positioned adjacent the first face 122 of the intermediate web
120A. The web imprinting surface 222 is positioned adjacent the
second face 124 of the web 120A. The second felt layer 360 is
positioned in the compression nip 300 such that the second felt
layer 360 is in flow communication with the deflection conduit
portion 230.
[0085] Referring again to FIG. 8, the first surface 325 of the
first dewatering felt 320 is positioned adjacent the first face 122
of the intermediate web 120A as the first dewatering felt 320 is
driven around the nip roll 322. Similarly, the first surface 365 of
the second dewatering felt 360 is positioned adjacent the second
felt contacting face 240 of the foraminous imprinting member 219 as
the second dewatering felt 360 is driven around the nip roll 362.
Accordingly, as the intermediate web 120A is carried through the
compression nip 300 on the foraminous imprinting fabric 219, the
intermediate web 120A, the imprinting fabric 219, and the first and
second dewatering felts 320 and 360 are pressed together between
the opposed surfaces of the nip rolls 322 and 362. Pressing the
intermediate web 120A in the compression nip 300 further deflects
the paper making fibers into the deflection conduit portion 230 of
the imprinting member 219, and removes water from the intermediate
web 120A to form the molded web 120B. The water removed from the
web is received by and contained in the dewatering felts 320 and
360. Water is received by the dewatering felt 360 through the
deflection conduit portion 230 of the imprinting member 219.
[0086] The molded web 120B is preferably pressed to have a
consistency of at least about 30 percent at the exit of the
compression nip 300. Pressing the intermediate web 120A as shown in
FIG. 8 molds the web to provide a first relatively high density
region associated with the web imprinting surface 222 and a second
relatively low density region of the web associated with the
deflection conduit portion 230. Pressing the intermediate web 120A
on an imprinting fabric 219 having a macroscopically mono-planar,
patterned, continuous network web imprinting surface 222, can be
provided as a molded web 120B having a macroscopically mono-planar,
patterned, continuous network regions having a relatively high
density, and a plurality of discrete, relatively low density domes
dispersed throughout the continuous, relatively high density
network region. Alternatively, a continuous network web imprinting
surface 222, can be provided as a molded web 120B having a
macroscopically mono-planar, patterned, continuous network regions
having a relatively low density, and a plurality of discrete,
relatively high density domes dispersed throughout the continuous,
relatively low density network region. Further, a continuous
network web imprinting surface 222, can be provided as a molded web
120B having macroscopically mono-planar, patterned, continuous
network regions having a relatively low density, and continuous
network regions having a relatively high density dispersed adjacent
the continuous, relatively low density network region.
Alternatively, a continuous network web imprinting surface 222, can
be provided as a molded web 120B having macroscopically
mono-planar, patterned, discrete regions having a relatively low
density, and discrete regions having a relatively high density
dispersed adjacent the discrete, relatively low density network
regions.
[0087] A sixth step in the practice of the present invention can
comprise pre-drying the molded web 120B, such as with a through-air
dryer 400 as shown in FIG. 8. The molded web 120B can be pre-dried
by directing a drying gas, such as heated air, through the molded
web 120B. In one embodiment, the heated air is directed first
through the molded web 120B from the first web face 122 to the
second web face 124, and subsequently through the deflection
conduit portion 230 of the imprinting member 219 on which the
molded web is carried. The air directed through the molded web 120B
partially dries the molded web 120B. In addition, without being
limited by theory, it is believed that air passing through the
portion of the web associated with the deflection conduit portion
230 can further deflect the web into the deflection conduit portion
230, and reduce the density of the relatively low density region,
thereby increasing the bulk and apparent softness of the molded web
120B. In one embodiment the molded web 120B can have a consistency
of between about 30 and about 65 percent upon entering the
through-air dryer 400, and a consistency of between about 40 and
about 80 upon exiting the through-air dryer 400.
[0088] The through-air dryer 400 can comprise a hollow rotating
drum 410. The molded web 120B can be carried around the hollow drum
410 on the imprinting member 219, and heated air can be directed
radially outward from the hollow drum 410 to pass through the web
120B and the imprinting member 219. Alternatively, the heated air
can be directed radially inward (not shown). Alternatively, one or
more through-air dryers 400 or other suitable drying devices can be
located upstream of the nip 300 to partially dry the web prior to
pressing the web in the nip 300.
[0089] A seventh step in the practice of the present invention can
comprise impressing the web imprinting surface of the foraminous
imprinting member 219 into the molded web 120B to form an imprinted
web 120C. Impressing the web imprinting surface into the molded web
120B serves to further densify, the relatively high density region
of the molded web, thereby increasing the difference in density
between the regions. Referring to FIG. 8, the molded web 120B is
carried on the imprinting member 219 and interposed between the
imprinting member 219 and an impression surface at a nip 490. The
impression surface can comprise a surface 512 of a heated drying
drum 510, and the nip 490 can be formed between a roll 209 and the
dryer drum 510. The imprinted web 120C can then be adhered to the
surface 512 of the dryer drum 510 with the aid of a creping
adhesive, and finally dried. The dried, imprinted web 120C can be
foreshortened as it is removed from the dryer drum 510, such as by
creping the imprinted web 120C from the dryer drum with a doctor
blade 524. "Creped" or "creping" as used herein means creped off of
a Yankee dryer or other similar roll and/or fabric creped and/or
belt creped. Rush transfer of a fibrous structure alone does not
result in a "creped" fibrous structure or "creped" sanitary tissue
product for purposes of the present invention.
[0090] One of ordinary skill will recognize that the simultaneous
imprinting, dewatering, and transfer operations may occur in
embodiments other than those using dryer drum such as a Yankee
drying drum. For example, two flat surfaces may be juxtaposed to
form an elongate nip therebetween. Alternatively, two unheated
rolls may be utilized. The rolls may be, for example, part of a
calendar stack, or an operation which prints a functional additive
onto the surface of the web. Functional additives may include:
lotions, emollients, dimethicones, softeners, perfumes, menthols,
combinations thereof, and the like.
[0091] The method provided by the present invention is particularly
useful for making paper webs having a basis weight of between about
10 grams per square meter to about 65 grams per square meter. Such
paper webs are suitable for use in the manufacture of single and
multiple ply tissue and paper towel products.
[0092] Additionally, paper webs produced by the processes described
herein can be embossed. "Embossed" as used herein with respect to a
fibrous structure and/or sanitary tissue product means that a
fibrous structure and/or sanitary tissue product has been subjected
to a process which converts a smooth surfaced fibrous structure
and/or sanitary tissue product to a decorative surface by
replicating a design on one or more emboss rolls, which form a nip
through which the fibrous structure and/or sanitary tissue product
passes. Embossed does not include creping, micro-creping, printing
or other processes that may also impart a texture and/or decorative
pattern to a fibrous structure and/or sanitary tissue product.
[0093] If hand sheets are desired, one of skill in the art could
utilize the accept pulp was then utilized to form a papermaking
slurry. The method of transferring the web is as follows: First,
the web is formed on a plastic mesh cloth (84.times.76-M from
Appleton Wire Company, or equivalent). The orientation of the cloth
should be so that the sheet is formed on the side with discernible
strands in one direction (the other side of the cloth is smooth in
both directions). For the present work, a 12 inch by 12 inch deckle
box is employed in the tests described herein (although equivalent
sizes would also be acceptable). The hand sheet mold is equipped to
retain the cloth during sheet forming, and then allow its release
with the wet web intact on its surface. Excess water is removed by
subjecting the cloth, with the wet web on its surface, to a vacuum
of from 3.5 to 4.5 inches of mercury. The vacuum is applied by
pulling the cloth across a vacuum slot at a rate of about 1 foot
per second. The direction of travel is selected so that the forming
cloth is pulled perpendicular to the direction of its discernible
strands. The web, so prepared, is transferred onto a 36.times.30
polyester fabric cloth (e.g., a 36-C from Appleton Wire, or
equivalent) by a vacuum of from 9.5 to 10.5 inches of mercury over
the vacuum slot. The direction of motion of the web is the same in
both vacuum steps, and the 36.times.30 cloth is used so that the
direction having 36 strands is used as the direction of motion.
[0094] The wet web and the polyester fabric are dried together on a
heated stainless steel dryer drum that is 18 inches wide and 12
inches in diameter. The drum is maintained at a surface temperature
of 230.degree. F., and rotated at a speed of from 0.85 to 0.95
revolutions per minute. The wet web and polyester fabric are
inserted between the dryer surface and a felt covering the surface
and mounted to travel at the same speed as the drum. A felt of
1/8'' thickness, style #1044; Commonwealth Felt Company, 136 West
Street Northhampton, Mass. 01060 (or equivalent) is employed. The
felt is wrapped to cover 63% of the dryer circumference. The wet
web is dried in this manner twice with the direction of motion from
the transfer step being maintained each time. The first drying step
is completed with the fabric next to the dryer surface; the second
step with the web next to the surface.
[0095] Because this method of hand-sheeting introduces a chance for
a slight anisotropy to be created, all testing is performed in both
directions with the result averaged to obtain a single value.
Further hand-sheets formed by the above described process can be
designed to simulate lightweight, low density tissue papers. The
hand-sheeting procedure is similar to that described in TAPPI
Standard T 205 os-71, except that a lower basis weight is used. In
addition, the method of transferring the web from the forming wire
and the method of drying the paper are modified. The modifications
from the industry standard method are described below. The amount
of pulp added is adjusted to result in a conditioned basis weight
of 26.9 g/m.sup.2.
[0096] The fibrous structures and/or sanitary tissue products of
the present disclosure may be creped or uncreped. The fibrous
structures and/or sanitary tissue products of the present
disclosure may be wet-laid or air-laid. The fibrous structures
and/or sanitary tissue products of the present disclosure may be
embossed. The fibrous structures and/or sanitary tissue products of
the present disclosure may comprise a surface softening agent or be
void of a surface softening agent. In one example, the sanitary
tissue product is a non-lotioned sanitary tissue product. The
fibrous structures and/or sanitary tissue products of the present
disclosure may comprise trichome fibers and/or may be void of
trichome fibers.
Example
[0097] This example illustrates a non-limiting example of an
exemplary method of making improved cellulose pulps which meet the
criteria of the present invention by a process consisting
essentially of fines removal and hydraulic cyclones. The following
example also illustrates a non-limiting example for a preparation
of a sanitary tissue product comprising a fibrous structure
according to the present invention on a pilot-scale Fourdrinier
fibrous structure making (papermaking) machine.
[0098] Referring again to FIG. 7A, an aqueous slurry of eucalyptus
(Brazilian bleached hardwood kraft pulp) feed pulp fibers is
treated by a fractionation process incorporating a two-stage system
as described supra. A first product stream from the first stage
results in an "accept" fiber product that has a lower percentage of
vessels than the feed pulp. The second product stream from the
first stage results in the product known by one of skill in the art
as "reject" product and has a higher percentage of vessels than the
feed pulp. The second product stream from the first stage provides
the input pulp stream feed to the second stage. The second stage
provides a third product stream resulting in additional "accepts"
product having a lower percentage of vessels than the initial
starting product. This third product stream is re-fed into the
first stage. The fourth product stream from the second stage
results in the "rejects" product having a higher percentage of
vessels than the initial starting product.
[0099] In one embodiment, the first stage of a two-stage
fractionation process is provided with process settings that
provide a pressure drop of about 25.3 psi. The second stage of a
two-stage fractionation process is provided with process settings
that provide a pressure drop of about 26.5 psi.
[0100] In another embodiment, the first stage of a two-stage
fractionation process is provided with process settings that
provide a pressure drop of about 27.6 psi. The second stage of a
two-stage fractionation process is provided with process settings
that provide a pressure drop of about 26.5 psi.
[0101] Feed pulp was supplied to the hydrocyclone unit at -3%
consistency which was then diluted to 0.5-0.7% and fed to the first
hydrocyclone unit. The accept stream from the first hydrocyclone
unit had about a 0.4-0.5% consistency. The reject stream from the
first hydrocyclone unit was thickened to about 1%. The reject
stream from the first hydrocyclone unit was then sent to a second
hydrocyclone unit and diluted to 0.4-0.5% consistency. The accept
product from the second hydrocyclone unit (having about a 0.4%
consistency) was directed to the feed of the first hydrocyclone
unit. The rejects from the second hydrocyclone unit were thickened
to about a 1% consistency.
[0102] In any regard, the accept stream exiting the first stage is
recovered and saved and transferred to the papermaking hardwood
fiber stock chest. The eucalyptus fiber slurry of the hardwood
fiber stock chest is pumped through a stock pipe to a hardwood fan
pump where the slurry consistency is reduced from about 3% by fiber
weight to about 0.15% by fiber weight. The 0.15% eucalyptus
"accept" slurry was then pumped and distributed in the top chamber
of a multi-layered, three-chambered head box of a Fourdrinier
wet-laid papermaking machine.
[0103] Additionally, a second aqueous slurry of either
un-fractionated Eucalyptus pulp fibers and/or that portion of the
fractionated Eucalyptus pulp fibers from the "reject" stream is
prepared at about 3% fiber by weight using a conventional
re-pulper, then transferred to a reject fiber stock chest. The NSK
fiber slurry of the softwood stock chest is pumped through a stock
pipe to be refined to a Canadian Standard Freeness (CSF) of about
630. The refined NSK fiber slurry is then directed to the NSK fan
pump where the NSK slurry consistency is reduced from about 3% by
fiber weight to about 0.15% by fiber weight. The 0.15%
un-fractionated or "reject" eucalyptus slurry is then directed and
distributed to the center chamber of a multi-layered,
three-chambered head box of a Fourdrinier wet-laid papermaking
machine.
[0104] In order to impart temporary wet strength to the finished
fibrous structure, a 1% dispersion of temporary wet strengthening
additive (e.g., Parez.RTM. commercially available from Kemira) is
prepared and is added to the NSK fiber stock pipe at a rate
sufficient to deliver 0.3% temporary wet strengthening additive
based on the dry weight of the NSK fibers. The absorption of the
temporary wet strengthening additive is enhanced by passing the
treated slurry through an in-line mixer.
[0105] The wet-laid papermaking machine has a layered head box
having a top chamber, a center chamber, and a bottom chamber where
the chambers feed directly onto the forming wire (Fourdrinier
wire). The eucalyptus fiber slurry of 0.15% consistency is directed
to the top head box chamber and bottom head box chamber. The NSK
fiber slurry is directed to the center head box chamber. All three
fiber layers are delivered simultaneously in superposed relation
onto the Fourdrinier wire to form thereon a three-layer embryonic
fibrous structure (web), of which about 33% of the top side is made
up of the eucalyptus fibers, about 33% is made of the eucalyptus
fibers on the bottom side and about 34% is made up of the NSK
fibers in the center. Dewatering occurs through the Fourdrinier
wire and is assisted by a deflector and wire table vacuum boxes.
The Fourdrinier wire is an 84M (84 by 76 5A, Albany International).
The speed of the Fourdrinier wire is about 800 feet per minute
(fpm).
[0106] The embryonic wet fibrous structure is transferred from the
Fourdrinier wire, at a fiber consistency of about 16-20% at the
point of transfer, to a 3D patterned through-air-drying belt. The
speed of the 3D patterned through-air-drying belt is the same as
the speed of the Fourdrinier wire. The 3D patterned
through-air-drying belt is designed to yield a fibrous structure
comprising a pattern of semi-continuous low density pillow regions
and semi-continuous high density knuckle regions. This 3D patterned
through-air-drying belt is formed by casting an impervious resin
surface onto a fiber mesh supporting fabric. The supporting fabric
is a 98.times.52 filament, dual layer fine mesh. The thickness of
the resin cast is about 13 mils above the supporting fabric.
[0107] Further de-watering of the fibrous structure is accomplished
by vacuum assisted drainage until the fibrous structure has a fiber
consistency of about 20% to 30%. While remaining in contact with
the 3D patterned through-air-drying belt, the fibrous structure is
pre-dried by air blow-through pre-dryers to a fiber consistency of
about 50-65% by weight.
[0108] After the pre-dryers, the semi-dry fibrous structure is
transferred to a Yankee dryer and adhered to the surface of the
Yankee dryer with a sprayed creping adhesive. The creping adhesive
is an aqueous dispersion with the actives consisting of about 80%
polyvinyl alcohol (PVA 88-50), about 20% CREPETROL.RTM. 457T20.
CREPETROL.RTM. 457T20 is commercially available from Solenis
(formerly Hercules Incorporated of Wilmington, Del.). The creping
adhesive is delivered to the Yankee surface at a rate of about
0.15% adhesive solids based on the dry weight of the fibrous
structure. The fiber consistency is increased to about 97% before
the fibrous structure is dry-creped from the Yankee with a doctor
blade.
[0109] The doctor blade has a bevel angle of about 25.degree. and
is positioned with respect to the Yankee dryer to provide an impact
angle of about 81.degree.. The Yankee dryer is operated at a
temperature of about 275.degree. F. and a speed of about 800 fpm.
The fibrous structure is wound in a roll (parent roll) using a
surface driven reel drum having a surface speed of about 695
fpm.
[0110] Two parent rolls of the fibrous structure can then converted
into a sanitary tissue product by loading the roll of fibrous
structure into an unwind stand at a line speed of 400 ft/min One
parent roll of the fibrous structure can be unwound and transported
to an embossing process where the fibrous structure can be strained
to form an emboss pattern in the fibrous structure. This embossed
ply can then be combined with an embossed or un-embossed fibrous
structure from the other parent roll to make a multi-ply (2-ply)
sanitary tissue product. The multi-ply sanitary tissue product is
then transported over a slot extruder through which a surface
chemistry may be applied. The multi-ply sanitary tissue product is
then transported to a winder where it is wound onto a core to form
a log. The log of multi-ply sanitary tissue product is then
transported to a log saw where the log is cut into finished
multi-ply sanitary tissue product rolls. The multi-ply sanitary
tissue product of this example exhibits the inventive properties
shown in the tables provided infra.
Test Methods
[0111] Unless otherwise specified, all tests described herein
including those described under the Definitions section and the
following test methods are conducted on samples that have been
conditioned in a conditioned room at a temperature of 23.degree.
C..+-.1.0.degree. C. and a relative humidity of 50%.+-.2% for a
minimum of 2 hours prior to testing. The samples tested are "usable
units." "Usable units" as used herein means sheets, flats from roll
stock, pre-converted flats, and/or single or multi-ply products.
All tests are conducted in such conditioned room. Do not test
samples that have defects such as wrinkles, tears, holes, and like.
All instruments are calibrated according to manufacturer's
specifications.
1. Basis Weight Test Method
[0112] Basis weight of a fibrous structure and/or sanitary tissue
product is measured on stacks of twelve usable units using a top
loading analytical balance with a resolution of .+-.0.001 g. The
balance is protected from air drafts and other disturbances using a
draft shield. A precision cutting die, measuring 3.500 in
.+-.0.0035 in by 3.500 in .+-.0.0035 in is used to prepare all
samples.
[0113] With a precision cutting die, cut the samples into squares.
Combine the cut squares to form a stack twelve samples thick.
Measure the mass of the sample stack and record the result to the
nearest 0.001 g.
[0114] The Basis Weight is calculated in lbs/3000 ft.sup.2 or
g/m.sup.2 as follows:
Basis Weight=(Mass of stack)/[(Area of 1 square in
stack).times.(No. of squares in stack)]
For example:
Basis Weight (lbs/3000 ft.sup.2)=[[Mass of stack (g)/453.6
(g/lbs)]/[12.25 (in.sup.2)/144
(in.sup.2/ft.sup.2).times.12]].times.3000
or,
Basis Weight (g/m.sup.2)=Mass of stack (g)/[79.032
(cm.sup.2)/10,000 (cm.sup.2/m.sup.2).times.12].
[0115] Report the numerical result to the nearest 0.1 lbs/3000
ft.sup.2 or 0.1 g/m.sup.2. Sample dimensions can be changed or
varied using a similar precision cutter as mentioned above, so as
at least 100 square inches of sample area in stack.
2. Caliper Test Method
[0116] Caliper of a fibrous structure and/or sanitary tissue
product is measured using a ProGage Thickness Tester (Thwing-Albert
Instrument Company, West Berlin, N.J.) with a pressure foot
diameter of 2.00 inches (area of 3.14 in.sup.2) at a pressure of 95
g/in.sup.2. Four (4) samples are prepared by cutting of a usable
unit such that each cut sample is at least 2.5 inches per side,
avoiding creases, folds, and obvious defects. An individual
specimen is placed on the anvil with the specimen centered
underneath the pressure foot. The foot is lowered at 0.03 in/sec to
an applied pressure of 95 g/in.sup.2. The reading is taken after 3
sec dwell time, and the foot is raised. The measure is repeated in
like fashion for the remaining 3 specimens. The caliper is
calculated as the average caliper of the four specimens and is
reported in mils (0.001 in) to the nearest 0.1 mils.
3. Pulp Fiber and Vessel Measurement Method (Fiber Quality
Analysis)
[0117] Pulp fiber and vessel measurements are obtained using the
Fiber Quality Analyzer (FQA) instrument (OpTest Equipment Inc.,
Ontario, Canada) running the FQA software including the vessel
analysis capability. The FQA is a fully integrated patented flow
cell system with optics, control and measurement electronics, and
pneumatic and liquid systems. This instrument rapidly, accurately
and automatically measures the quality of a disintegrated pulp
sample dispersed in water. The qualities measured by the instrument
include fiber length (true contour length), fiber width,
coarseness, fiber curl, fiber kink, and % fines. Additionally, the
instrument detects and measures the number of vessel elements
counted, the mean vessel area, mean vessel effective length and
width, and the number of vessel elements per meter of fiber. The
sample preparation, instrument operation and testing procedures are
performed according the instrument manufacture's
specifications.
Sample Preparation
[0118] According to the instrument manufacturer's instruction,
obtain a dry pulp sample from a sheet, disintegrate and disperse
the sample in water, then dilute the sample to the necessary
testing conditions. The aim is to dilute the pulp sample to achieve
a target fiber frequency of events per second (EPS) during the
test, which will vary depending on the type of pulp (hardwood or
softwood) being analyzed.
Testing Procedure
[0119] Perform the fiber and vessel analysis test on the prepared
pulp sample according to the instrument manufacturer's
specifications using default test limit settings where optional.
For vessel identification and analysis by the FQA, use a minimum
vessel element width setting of 100 .mu.m and length setting of
0.10 mm Due to the low frequency of vessel elements in most pulp
samples, test a sufficient volume of pulp sample to measure enough
vessel elements for the vessel element results to be statistically
significant.
Report and record the pulp fiber measurement results for the pulp
sample to the appropriate significant figures. These include the
fiber length (true contour length), fiber width, coarseness, fiber
curl, fiber kink, and % fines. Additionally, report and record the
vessel measurement results for the pulp sample to the appropriate
significant figures. These include the number of vessel elements
counted, the mean vessel area, mean vessel effective length and
width, and the number of vessel elements per meter of fiber.
4. Tensile Test Method: Elongation, Tensile Strength, TEA and
Modulus
[0120] For the purposes of determining, calculating, and reporting
`wet burst`, `total dry tensile`, and `dynamic coefficient of
friction` values infra, a unit of `user units` is hereby utilized
for the products subject to the respective test method. As would be
known to those of skill in the art, bath tissue and paper toweling
are typically provided in a perforated roll format where the
perforations are capable of separating the tissue or towel product
into individual units. A `user unit` (uu) is the typical finished
product unit that a consumer would utilize in the normal course of
use of that product. A single-, double, or even triple-ply finished
product that a consumer would normally use would have a value of
one user unit (uu). For example, facial tissues that are not
normally provided in a roll format, but as a stacked plurality of
discreet tissues, a facial tissue having one ply would have a value
of 1 user unit (uu). An individual two-ply facial tissue product
would have a value of one user unit (1 uu), etc.
[0121] Elongation, Tensile Strength, TEA and Tangent Modulus are
measured on a constant rate of extension tensile tester with
computer interface (a suitable instrument is the EJA Vantage from
the Thwing-Albert Instrument Co. Wet Berlin, N.J.) using a load
cell for which the forces measured are within 10% to 90% of the
limit of the cell. Both the movable (upper) and stationary (lower)
pneumatic jaws are fitted with smooth stainless steel faced grips,
25.4 mm in height and wider than the width of the test specimen. An
air pressure of about 60 psi is supplied to the jaws.
[0122] Eight usable units of fibrous structure are divided into two
stacks of four samples each. The samples in each stack are
consistently oriented with respect to machine direction (MD) and
cross direction (CD). One of the stacks is designated for testing
in the MD and the other for CD. Using a one inch precision cutter
(Thwing Albert JDC-1-10, or similar) cut 4 MD strips from one
stack, and 4 CD strips from the other, with dimensions of 1.00 in
.+-.0.01 in wide by 3.0-4.0 in long. Each strip of one usable unit
thick will be treated as a unitary specimen for testing.
[0123] Program the tensile tester to perform an extension test,
collecting force and extension data at an acquisition rate of 20 Hz
as the crosshead raises at a rate of 2.00 in/min (5.08 cm/min)
until the specimen breaks. The break sensitivity is set to 80%,
i.e., the test is terminated when the measured force drops to 20%
of the maximum peak force, after which the crosshead is returned to
its original position.
[0124] Set the gauge length to 1.00 inch. Zero the crosshead and
load cell. Insert at least 1.0 in of the unitary specimen into the
upper grip, aligning it vertically within the upper and lower jaws
and close the upper grips. Insert the unitary specimen into the
lower grips and close. The unitary specimen should be under enough
tension to eliminate any slack, but less than 5.0 g of force on the
load cell. Start the tensile tester and data collection. Repeat
testing in like fashion for all four CD and four MD unitary
specimens.
[0125] Program the software to calculate the following from the
constructed force (g) verses extension (in) curve:
[0126] Tensile Strength is the maximum peak force (g) divided by
the sample width (in) and reported as g/in to the nearest 1
g/M.
[0127] Adjusted Gauge Length is calculated as the extension
measured at 3.0 g of force (in) added to the original gauge length
(in).
[0128] Elongation is calculated as the extension at maximum peak
force (in) divided by the Adjusted Gauge Length (in) multiplied by
100 and reported as % to the nearest 0.1%.
[0129] Total Energy (TEA) is calculated as the area under the force
curve integrated from zero extension to the extension at the
maximum peak force (g*in), divided by the product of the adjusted
Gauge Length (in) and specimen width (in) and is reported out to
the nearest 1 g*in/in.sup.2.
[0130] Replot the force (g) verses extension (in) curve as a force
(g) verses strain curve. Strain is herein defined as the extension
(in) divided by the Adjusted Gauge Length (in).
[0131] Program the software to calculate the following from the
constructed force (g) verses strain curve:
[0132] Tangent Modulus is calculated as the slope of the linear
line drawn between the two data points on the force (g) versus
strain curve, where one of the data points used is the first data
point recorded after 28 g force, and the other data point used is
the first data point recorded after 48 g force. This slope is then
divided by the specimen width (2.54 cm) and reported to the nearest
1 g/cm.
[0133] The Tensile Strength (g/in), Elongation (%), Total Energy
(g*in/in.sup.2) and Tangent Modulus (g/cm) are calculated for the
four CD unitary specimens and the four MD unitary specimens.
Calculate an average for each parameter separately for the CD and
MD specimens.
Calculations:
[0134] Geometric Mean Tensile=Square Root of [MD Tensile Strength
(g/in).times.CD Tensile Strength (g/in)]
Geometric Mean Peak Elongation=Square Root of [MD Elongation
(%).times.CD Elongation (%)]
Geometric Mean TEA=Square Root of [MD TEA (g*in/in.sup.2).times.CD
TEA (g*in/in.sup.2)]
Geometric Mean Modulus=Square Root of [MD Modulus (g/cm).times.CD
Modulus (g/cm)]
Total Dry Tensile Strength (TDT)=MD Tensile Strength (g/in)+CD
Tensile Strength (g/in)
Total TEA=MD TEA (g*in/in.sup.2)+CD TEA (g*in/in.sup.2)
Total Modulus=MD Modulus (g/cm)+CD Modulus (g/cm)
Tensile Ratio=MD Tensile Strength (g/in)/CD Tensile Strength
(g/in)
5. Initial Total Wet Tensile Test Method
[0135] The initial total wet tensile of a dry fibrous structure is
determined using a Thwing-Albert EJA Material Tester Instrument,
Cat. No. 1350, equipped with 5000 g load cell available from
Thwing-Albert Instrument Company, 14 Collings Ave. W. Berlin, N.J.
08091. 10% of the 5000 g load cell is utilized for the initial
total wet tensile test. [0136] i. Sample Preparation--A sample
strip of dry fibrous structure to be tested [2.54 cm (1 inch) wide
by greater than 5.08 cm (2 inches)] long is obtained. [0137] ii.
Operation--The test settings for the instrument are: [0138]
Crosshead speed--10.16 cm/minute (4.0 inches/minute) [0139] Initial
gauge length 2.54 cm (1.0 inch) [0140] Adjust the load cell to read
zero plus or minus 0.5 grams.sub.force (g.sub.f) [0141] iii.
Testing Samples--One end of the sample strip is placed between the
upper jaws of the machine and clamped. After verifying that the
sample strip is hanging straight between the lower jaws, clamp the
other end of the sample strip in the lower jaws.
[0142] a. Pre-Test--Strain the sample strip to 25 grams.sub.force
(+/-10 grams.sub.force) at a strain rate of 3.38 cm/minute (1.33
inches/minute) prior to wetting the sample strip. The distance
between the upper and lower jaws is now greater than 2.54 cm (1.0
inch). This distance now becomes the new zerostrain position for
the forthcoming wet test described below.
[0143] b. Wet Test--While the sample strip is still at 25
grams.sub.force (+/-10 grams.sub.force) it is wetted, starting near
the upper jaws, a water/0.1% Pegosperse.RTM. ML200 (available from
Lonza Inc. of Allendale, N.J.) solution [having a temperature of
about 73.degree. F..+-.4.degree. F. (about 23.degree.
C..+-.2.2.degree. C.)] is delivered to the sample strip via a 2 mL
disposable pipette. Do not contact the sample strip with the
pipette and do not damage the sample strip by using excessive
squirting pressure. The solution is continuously added until the
sample strip is visually determined to be completely saturated
between the upper and lower jaws. At this point, the load cell is
re-adjusted to read 0.+-.0.5 grams.sub.force. The sample strip is
then strained at a rate of 10.16 cm/minute (4 inches/minute) and
continues until the sample strip is strained past its failure point
(failure point being defined as the point on the force-strain curve
where the sample strip falls to 50% of its peak strength after it
has been strained past its peak strength). The straining of the
sample strip is initiated between 5-10 seconds after the sample is
initially wetted. The initial result of the test is an array of
data points in the form of load (grams.sub.force) versus strain
(where strain is calculated as the crosshead displacement (cm of
jaw movement from starting point) divided by the initial separation
distance (cm) between the upper and lower jaws after the
pre-test.
[0144] The sample is tested in two orientations, referred to here
as MD (machine direction, i.e., in the same direction as the
continuously wound reel and forming fabric) and CD (cross-machine
direction, i.e., 90.degree. from MD). The MD and CD initial wet
tensile strengths are determined using the above equipment and the
initial total wet tensile values are calculated in the following
manner:
ITWT (g/inch)=Peak Load.sub.MD (g.sub.f)/1 (inch.sub.width)+Peak
Load.sub.CD (g.sub.f)/1 (inch.sub.withh)
6. Vertical Full Sheet (VFS) Test Method
[0145] The Vertical Full Sheet (VFS) test method determines the
amount of distilled water absorbed and retained by a fibrous
structure of the present invention. This method is performed by
first weighing a sample of the fibrous structure to be tested
(referred to herein as the "dry weight of the sample"), then
thoroughly wetting the sample, draining the wetted sample in a
vertical position and then reweighing (referred to herein as "wet
weight of the sample"). The absorptive capacity of the sample is
then computed as the amount of water retained in units of grams of
water absorbed by the sample. When evaluating different fibrous
structure samples, the same size of fibrous structure is used for
all samples tested.
[0146] The apparatus for determining the VFS capacity of fibrous
structures comprises the following:
[0147] 1) An electronic balance with a sensitivity of at least
.+-.0.01 grams and a minimum capacity of 1200 grams. The balance
should be positioned on a balance table and slab to minimize the
vibration effects of floor bench-top weighing. The balance should
also have a special balance pan to be able to handle the size of
the sample tested (i.e.; a fibrous structure sample of about 11 in.
(27.9 cm) by 11 in. (27.9 cm)). The balance pan can be made out of
a variety of materials. Plexiglass is a common material used.
[0148] 2) A sample support rack and sample support rack cover is
also required. Both the rack and cover are comprised of a
lightweight metal frame, strung with 0.012 in. (0.305 cm) diameter
monofilament so as to form a grid. The size of the support rack and
cover is such that the sample size can be conveniently placed
between the two.
[0149] The VFS test is performed in an environment maintained at
23.+-.1.degree. C. and 50.+-.2% relative humidity. A water
reservoir or tub is filled with distilled water at 23.+-.10 C to a
depth of 3 inches (7.6 cm).
[0150] Eight 19.05 cm (7.5 inch).times.19.05 cm (7.5 inch) to 27.94
cm (11 inch).times.27.94 cm (11 inch) samples of a fibrous
structure to be tested are carefully weighed on the balance to the
nearest 0.01 grams. The dry weight of each sample is reported to
the nearest 0.01 grams. The empty sample support rack is placed on
the balance with the special balance pan described above. The
balance is then zeroed (tared). One sample is carefully placed on
the sample support rack. The support rack cover is placed on top of
the support rack. The sample (now sandwiched between the rack and
cover) is submerged in the water reservoir. After the sample is
submerged for 60 seconds, the sample support rack and cover are
gently raised out of the reservoir.
[0151] The sample, support rack and cover are allowed to drain
vertically for 60.+-.5 seconds, taking care not to excessively
shake or vibrate the sample. While the sample is draining, the rack
cover is carefully removed and all excess water is wiped from the
support rack. The wet sample and the support rack are weighed on
the previously tared balance. The weight is recorded to the nearest
0.01 g. This is the wet weight of the sample.
[0152] The procedure is repeated for with another sample of the
fibrous structure, however, the sample is positioned on the support
rack such that the sample is rotated 90.degree. compared to the
position of the first sample on the support rack. The gram per
fibrous structure sample absorptive capacity of the sample is
defined as (wet weight of the sample-dry weight of the sample). The
calculated VFS is the average of the absorptive capacities of the
two samples of the fibrous structure.
7. Capacity Rate Test
[0153] Conditioned Room--Temperature is controlled from 73.degree.
F..+-.2.degree. F. (23.degree. C..+-.1.degree. C.). Relative
Humidity is controlled from 50%.+-.2%
[0154] Sample Preparation--Product samples are cut using
hydraulic/pneumatic precision cutter into 3.375 inch diameter
circles.
[0155] Capacity Rate Tester (CRT)--The CRT is an absorbency tester
capable of measuring capacity and rate. The CRT consists of a
balance (0.001 g), on which rests on a woven grid (using nylon
monofilament line having a 0.014'' diameter) placed over a small
reservoir with a delivery tube in the center. This reservoir is
filled by the action of solenoid valves, which help to connect the
sample supply reservoir to an intermediate reservoir, the water
level of which is monitored by an optical sensor. The CRT is run
with a -2 mm water column, controlled by adjusting the height of
water in the supply reservoir.
[0156] Software--LabView based custom software specific to CRT
Version 4.2 or later.
[0157] Water--Distilled water with conductivity<100/cm
(target<5 .mu.S/cm) @ 25.degree. C.
[0158] Sample Preparation--For this method, a usable unit is
described as one finished product unit regardless of the number of
plies. Condition all samples with packaging materials removed for a
minimum of 2 hours prior to testing. Discard at least the first ten
usable units from the roll. Remove two usable units and cut one
3.0-inch circular sample from the center of each usable unit for a
total of 2 replicates for each test result. Do not test samples
with defects such as wrinkles, tears, holes, etc. Replace with
another usable unit which is free of such defects.
Sample Testing Pre-Test Set-Up
[0159] 1. The water height in the reservoir tank is set -2.0 mm
below the top of the support rack (where the towel sample will be
placed).
[0160] 2. The supply tube (8 mm I.D.) is centered with respect to
the support net.
[0161] 3. Test samples are cut into circles of 3'' diameter and
equilibrated at Tappi environment conditions for a minimum of 2
hours.
Test Description
[0162] 1. After pressing the start button on the software
application, the supply tube moves to 0.33 mm below the water
height in the reserve tank. This creates a small meniscus of water
above the supply tube to ensure test initiation. A valve between
the tank and the supply tube closes, and the scale is zeroed.
[0163] 2. The software prompts you to "load a sample". A sample is
placed on the support net, centering it over the supply tube, and
with the side facing the outside of the roll placed downward.
[0164] 3. Close the balance windows, and press the "OK" button--the
software records the dry weight of the sample.
[0165] 4. The software prompts you to "place cover on sample". The
plastic cover is placed on top of the sample, on top of the support
net. The plastic cover has a center pin (which is flush with the
outside rim) to ensure that the sample is in the proper position to
establish hydraulic connection. Optionally, four other pins, 1 mm
shorter in depth, are positioned 1.25-1.5 inches radially away from
the center pin to ensure the sample is flat during the test. The
sample cover rim should not contact the sheet. Close the top
balance window and click "OK".
[0166] 5. The software re-zeroes the scale and then moves the
supply tube towards the sample. When the supply tube reaches its
destination, which is 0.33 mm below the support net, the valve
opens (i.e., the valve between the reserve tank and the supply
tube), and hydraulic connection is established between the supply
tube and the sample. Data acquisition occurs at a rate of 5 Hz, and
is started about 0.4 seconds before water contacts the sample.
[0167] 6. The test runs until the instrument measures the rate of
uptake to be less than 1.5 mg/sec. Specifically, the instrument
keeps a running tally of the amount of fluid taken up by the
sample. When the amount of fluid taken up over the last 6 seconds
is less than 9 mg, the test terminates. The supply tube pulls away
from the sample to break the hydraulic connection.
[0168] 7. The software records the weight on the scale. This weight
represents only the amount of water taken up by the sample.
[0169] 8. The wet sample is removed from the support net. Residual
water on the support net and cover are dried with a paper
towel.
[0170] 9. Repeat until all samples are tested.
[0171] 10. After each test is run, a *.txt file is created
(typically stored in the CRT/data/rate directory) with a file name
as typed at the start of the test. The file contains all the test
set-up parameters, dry sample weight, and cumulative water absorbed
(g) vs. time (sec) data collected from the test.
[0172] The CRT value is calculated by dividing the weight of water
absorbed (as recorded at the end of the test) by the weight of the
dry sample taken in step 3. The units of CRT value are g/g.
8. Lint Test Method
[0173] i. Sample Preparation--Sample strips (a total of 4 if
testing both sides, 2 if testing a single side) of fibrous
structures and/or sanitary tissue products, which do not have
abraded portions) 11.43 cm (4.5 inch) wide.times.30.48 cm to 40.64
cm (12-16 inch) long such that each sample strip can be folded upon
itself to form a 11.43 cm (4.5 inch) wide (CD) by 10.16 cm (4.0
inch) long (MD) rectangular implement having a total basis weight
of between 140 to 200 g/m.sup.2 are obtained and conditioned
according to Tappi Method #T402OM-88. For both side testing, makeup
two rectangular implements as described above with a first side out
and then two rectangular implements with the other side out (keep
track of which are which).
[0174] For sanitary tissue products formed from multiple plies of
fibrous structure, this test can be used to make a lint measurement
on the multi-ply sanitary tissue product, or, if the plies can be
separated without damaging the sanitary tissue product, a
measurement can be taken on the individual plies making up the
sanitary tissue product. If a given sample differs from surface to
surface, it is necessary to test both surfaces and average the
scores in order to arrive at a composite lint score. In some cases,
sanitary tissue products are made from multiple-plies of fibrous
structures such that the facing-out surfaces are identical, in
which case it is only necessary to test one surface.
[0175] Each sample is folded upon itself to make a 4.5''
CD.times.4'' MD sample. For two-surface testing, make up 3 (4.5''
CD.times.4'' MD) samples with a first surface "out" and 3 (4.5''
CD.times.4'' MD) samples with the second surface "out". Keep track
of which samples are first surface "out" and which are second
surface "out".
[0176] For a dry lint test, obtain a 30''.times.40'' piece of
Crescent #300 cardboard from Cordage Inc. (800 E. Ross Road,
Cincinnati, Ohio, 45217) or equivalent. Using a paper cutter, six
pieces of cardboard of dimensions of 6.35 cm.times.15.24 cm (2.5
inch.times.6 inch) are cut. Puncture two holes into each of the six
pieces of cardboard by forcing the cardboard onto the hold down
pins of the Sutherland Rub tester. Center and carefully place each
of the cardboard pieces on top of the previously folded samples
with the tested side exposed outward. Make sure the 15.24 cm (6
inch) dimension of the cardboard is running parallel to the machine
direction (MD) of each of the folded samples. Fold one edge of the
exposed portion of the sample onto the back of the cardboard.
Secure this edge to the cardboard with adhesive tape obtained from
3M Inc. (3/4'' wide Scotch Brand, St. Paul, Minn.) or equivalent.
Carefully grasp the other over-hanging tissue edge and snugly fold
it over onto the back of the cardboard. While maintaining a snug
fit of the sample onto the cardboard, tape this second edge to the
back of the cardboard. Repeat this procedure for each sample. Turn
over each sample and tape the cross direction edges of the sample
to the cardboard. One half of the adhesive tape should contact the
sample while the other half is adhering to the cardboard. Repeat
this procedure for each of the samples. If the sample breaks,
tears, or becomes frayed at any time during the course of this
sample preparation procedure, discard and make up a new sample with
a sample strip.
[0177] ii. Felt and Weight Component Preparation--Cut a piece of a
black test felt (F-55 or equivalent from New England Gasket, 550
Broad Street, Bristol, Conn. 06010) to the dimensions of
21/4''.times.71/4''. The felt is to be used in association with a
weight. The weight may include a clamping device to attach the
felt/cardboard combination to the weight. The weight and any
clamping device total five (5) pounds. The weight is available from
Danilee Company, San Antonio, Tex., and is associated with the
Sutherland Rub Tester. The weight has a 2''.times.4'' piece of
smooth surface foam attached to its contact face (1/8'' thick,
Poron quick Recovery Foam, adhesive back, firmness rating 13). For
the dry test, the felt is clamped directly against this foam
surface, providing an effective contact area of 8 in.sup.2 and a
contact pressure of about 0.625 psi. For the wet test, an
additional 1''.times.4'' foam strip (same foam as described above)
is attached and centered in the length direction on top the
2''.times.4'' foam strip, thus, after clamping the felt against
this surface, an effective contact area of 4 in.sup.2 and a contact
pressure of about 1.25 psi is established. Also, for the wet test
only, after clamping the felt to weight apparatus, two strips of
tape (41/4''-51/4'' in length, Scotch brand 3/4'' width) are placed
along each edge of the felt (parallel to the long side of the felt)
on the felt side that will be contacting the sample. The untaped
felt between the two tape strips has a width between 18-21 mm Three
marks are placed on one of the strips of tape at 0, 4 and 10
centimeters along the flat, test region of the test felt.
[0178] iii. Conducting Dry Lint Test--The amount of dry lint and/or
dry pills generated from a fibrous product according to the present
invention is determined with a Sutherland Rub Tester (available
from Danilee Company, San Antonio, Tex.). This tester uses a motor
to rub a felt/weight component 5 times (back and forth) over the
fibrous product, while the fibrous product is restrained in a
stationary position.
[0179] First, turn on the Sutherland Rub Tester pressing the
"reset" button. Set the tester to run 5 strokes at the lower of the
two speeds. One stroke is a single and complete forward and reverse
motion of the weight. The end of the rubbing block should be in the
position closest to the operator at the beginning and at the end of
each test.
[0180] Place the sample/cardboard combination on the base plate of
the tester by slipping the holes in the board over the hold-down
pins. The hold-down pins prevent the sample from moving during the
test. Hook the felt/weight combination into the tester arm of the
Sutherland Rub Tester, and gently place it on top of the
sample/cardboard combination. The felt must rest level on the
calibration sample and must be in 100% contact with the calibration
sample surface (use a bubble level indicator to verify). Activate
the Sutherland Rub Tester by pressing the "start" button.
[0181] Keep a count of the number of strokes and observe and make a
mental note of the starting and stopping position of the felt
covered weight in relationship to the sample. If the total number
of strokes is five and if the position of the calibration felt
covered weight is the same at the end as it was in the beginning of
the test, the test was successful performed. If the total number of
strokes is not five or if the start and end positions of the felt
covered weight are different, then the instrument may require
servicing and/or recalibration.
[0182] Once the instrument is finished moving, remove the felt
covered weight from the holding arm of the instrument, and unclamp
the felt from the weight. Lay the test felt on a clean, flat
surface.
[0183] The next step is to complete image capture, analysis, and
calculations on the test felts as described below.
[0184] vi. Image Capture--The images of the felt (untested), sample
(untested) and felt (tested) are captured using a computer and
scanner (Microtek ArtixScan 1800f). Be certain that scanner glass
is clear and clean. Place felts centered on scanner, face down.
Adjust image capture boundaries so that all felts are included into
the captured image. Set-up the scanner to 600 dpi, RGB, and 100%
image size (no scaling). After successfully imaging the felts, save
the image as an 8-bit RGB TIFF image, remove felts from scanner,
and repeat from process until all felts images are captured.
[0185] Additional images of the sample (untested) may need to be
captured (in the same manner) if they have an average luminance
(using Optimas software) significantly less than 254 (less than
244), after being converted to an 8-bit gray-scale image. Also, an
image of a known length standard (e.g., a ruler) is taken (exposure
difference does not matter for this image). This image is used to
calibrate the image analysis software distance scale.
[0186] vii. Image Analysis--The images captured are analyzed using
Optimas 6.5 Image Analysis software commercially available from
Media Cybernetics, L.P. Imaging set-up parameters, as listed
herein, must be strictly adhered to in order to have meaningfully
comparative lint score and pill score results.
[0187] First, an image with a known length standard (e.g., a ruler)
is brought up in Optimas, and used to calibrate length units
(millimeters in this case). For dry testing, the region of interest
(ROI) area is approximately 4500 mm2 (90 mm by 50 mm), and the
wetted and dragged ROI area is approximately 1500 mm2 (94 mm by 16
mm). The exact ROI area is measured and recorded (variable name:
ROI area). The average gray value of the un-rubbed region of the
test felt is used as the baseline, and is recorded for determining
the threshold and lint values (variable name: untested felt GV
avg). It is determined by creating a region of interest box (ROI)
with dimensions approximately 5 mm by 25 mm on the untested,
unrubbed area of the black felt, on opposite ends of the rubbed
region. The average of these two average gray value luminaces for
each of the ROI's is used as the untested felt GV average value for
that particular test felt. This is repeated for all test felts
analyzed. The test sheet luminance is typically near saturated
white (gray value 254) and fairly constant for samples of interest.
If believed to be different, measure the test sheet in a similar
fashion as was done for the untested felt, and record (variable
name=untested sheet GV avg). The luminance threshold is calculated
based on the untested felt GV avg and untested sheet GV avg as
follows:
[0188] For the dry lint/pilling test felts:
(untested_sheet_GV_avg-untested_felt_GV_avg)*0.4+untested_felt_GV_avg
For the wet lint/pilling test felts:
(untested_sheet_GV_avg-untested_felt_GV_avg)*0.25+untested_felt_GV_avg
[0189] The test felt image is opened, and the ROI and its
boundaries are created and properly positioned to encompass a
region that completely contains pills and contains the highest
concentration of pills on the rubbed section of the test felt. The
average luminance for the ROI is recorded (variable name: ROI GV
avg). Pills are determined as follows: Optimas creates boundary
lines in the image where pixel luminance values cross through the
threshold value (e.g., if the threshold is 120, boundary lines are
created where pixels of higher and lower value exist on either
side. The criteria for determining a pill is that it must have an
average luminance greater than the threshold value, and have a
perimeter length greater than 0.5 mm. The sum of the pilled areas
variable name is: Total Pilled Area.
[0190] Measurement data of the ROI, and for each pill is exported
from Optimas to a spreadsheet for performing the following
calculations.
[0191] viii. Calculations--The data obtained from the image
analysis is used in the following calculations:
Pilled Area %=Percent of area covered by pilling=Total Pilled
Area/ROI area
Lint Score=Gray value difference between un-pilled area of the
rubbed test felt area and the untested felt
Lint Score=un-pilled felt Gray Value avg-untested felt Gray Value
avg
[0192] where:
un-pilled felt Gray Value avg=[(ROI Gray Value avg*ROI
area)-(pilled Gray Value avg*pilled area)]/Total Un-pilled Area
[0193] By taking the average of the lint score of the first-side
surface and the second-side surface, the lint is obtained which is
applicable to that particular web or product. In other words, to
calculate lint score, the following formula is used:
Dry Lint Score = Dry Lint Score , 1 st side + Dry Lint Score , 2 nd
side 2 ##EQU00001## Dry Pill Area % = Dry Pill Area % , 1 st side +
Dry Pill Area % , 2 nd side 2 ##EQU00001.2##
9. Emtec TSA Test Method
[0194] TS7 and TS750 values are measured using an EMTEC Tissue
Softness Analyzer ("Emtec TSA") (Emtec Electronic GmbH, Leipzig,
Germany) interfaced with a computer running Emtec TSA software
(version 3.19 or equivalent). According to Emtec, the TS7 value
correlates with the real material softness, while the TS750 value
correlates with the felt smoothness/roughness of the material. The
Emtec TSA comprises a rotor with vertical blades which rotate on
the test sample at a defined and calibrated rotational speed (set
by manufacturer) and contact force of 100 mN. Contact between the
vertical blades and the test piece creates vibrations, which create
sound that is recorded by a microphone within the instrument. The
recorded sound file is then analyzed by the Emtec TSA software. The
sample preparation, instrument operation and testing procedures are
performed according the instrument manufacture's
specifications.
Sample Preparation
[0195] Test samples are prepared by cutting square or circular
samples from a finished product. Test samples are cut to a length
and width (or diameter if circular) of no less than about 90 mm,
and no greater than about 120 mm, in any of these dimensions, to
ensure the sample can be clamped into the TSA instrument properly.
Test samples are selected to avoid perforations, creases or folds
within the testing region. Prepare 8 substantially similar
replicate samples for testing. Equilibrate all samples at TAPPI
standard temperature and relative humidity conditions (23.degree.
C..+-.2 C..degree. and 50.+-.2%) for at least 1 hour prior to
conducting the TSA testing, which is also conducted under TAPPI
conditions.
Testing Procedure
[0196] Calibrate the instrument according to the manufacturer's
instructions using the 1-point calibration method on Emtec
reference 2.times. (nn.n) samples. If these reference samples are
no longer available, use the appropriate reference samples provided
by the manufacturer. Calibrate the instrument according to the
manufacturer's recommendation and instruction, so that the results
will be comparable to those obtained when using the 1-point
calibration method on Emtec reference 2.times. (nn.n) samples.
[0197] Mount the test sample into the instrument, and perform the
test according to the manufacturer's instructions. When complete,
the software displays values for TS7 and TS750. Record each of
these values to the nearest 0.01 dB V.sup.2 rms. The test piece is
then removed from the instrument and discarded. This testing is
performed individually on the top surface (outer facing surface of
a rolled product) of four of the replicate samples, and on the
bottom surface (inner facing surface of a rolled product) of the
other four replicate samples.
[0198] The four test result values for TS7 and TS750 from the top
surface are averaged (using a simple numerical average); the same
is done for the four test result values for TS7 and TS750 from the
bottom surface. Report the individual average values of TS7 and
TS750 for both the top and bottom surfaces on a particular test
sample to the nearest 0.01 dB V.sup.2 rms. Additionally, average
together all eight test value results for TS7 and TS750, and report
the overall average values for TS7 and TS750 on a particular test
sample to the nearest 0.01 dB V.sup.2 rms.
10. Flexural Rigidity Test Method
[0199] This test is performed on 1 inch.times.6 inch (2.54
cm.times.15.24 cm) strips of a fibrous structure sample. A
Cantilever Bending Tester such as described in ASTM Standard D 1388
(Model 5010, Instrument Marketing Services, Fairfield, N.J.) is
used and operated at a ramp angle of 41.5.+-.0.5.degree. and a
sample slide speed of 0.5.+-.0.2 in/second (1.3.+-.0.5 cm/second).
A minimum of n=16 tests are performed on each sample from n=8
sample strips.
[0200] No fibrous structure sample which is creased, bent, folded,
perforated, or in any other way weakened should ever be tested
using this test. A non-creased, non-bent, non-folded,
non-perforated, and non-weakened in any other way fibrous structure
sample should be used for testing under this test.
[0201] From one fibrous structure sample of about 4 inch.times.6
inch (10.16 cm.times.15.24 cm), carefully cut using a 1 inch (2.54
cm) JDC Cutter (available from Thwing-Albert Instrument Company,
Philadelphia, Pa.) four (4) 1 inch (2.54 cm) wide by 6 inch (15.24
cm) long strips of the fibrous structure in the MD direction. From
a second fibrous structure sample from the same sample set,
carefully cut four (4) 1 inch (2.54 cm) wide by 6 inch (15.24 cm)
long strips of the fibrous structure in the CD direction. It is
important that the cut be exactly perpendicular to the long
dimension of the strip. In cutting non-laminated two-ply fibrous
structure strips, the strips should be cut individually. The strip
should also be free of wrinkles or excessive mechanical
manipulation which can impact flexibility. Mark the direction very
lightly on one end of the strip, keeping the same surface of the
sample up for all strips. Later, the strips will be turned over for
testing, thus it is important that one surface of the strip be
clearly identified, however, it makes no difference which surface
of the sample is designated as the upper surface.
[0202] Using other portions of the fibrous structure (not the cut
strips), determine the basis weight of the fibrous structure sample
in lbs/3000 ft.sup.2 and the caliper of the fibrous structure in
mils (thousandths of an inch) using the standard procedures
disclosed herein. Place the Cantilever Bending Tester level on a
bench or table that is relatively free of vibration, excessive heat
and most importantly air drafts. Adjust the platform of the Tester
to horizontal as indicated by the leveling bubble and verify that
the ramp angle is at 41.5.+-.0.5.degree.. Remove the sample slide
bar from the top of the platform of the Tester. Place one of the
strips on the horizontal platform using care to align the strip
parallel with the movable sample slide. Align the strip exactly
even with the vertical edge of the Tester wherein the angular ramp
is attached or where the zero mark line is scribed on the Tester.
Carefully place the sample slide bar back on top of the sample
strip in the Tester. The sample slide bar must be carefully placed
so that the strip is not wrinkled or moved from its initial
position.
[0203] Move the strip and movable sample slide at a rate of
approximately 0.5.+-.0.2 in/second (1.3.+-.0.5 cm/second) toward
the end of the Tester to which the angular ramp is attached. This
can be accomplished with either a manual or automatic Tester.
Ensure that no slippage between the strip and movable sample slide
occurs. As the sample slide bar and strip project over the edge of
the Tester, the strip will begin to bend, or drape downward. Stop
moving the sample slide bar the instant the leading edge of the
strip falls level with the ramp edge. Read and record the overhang
length from the linear scale to the nearest 0.5 mm Record the
distance the sample slide bar has moved in cm as overhang length.
This test sequence is performed a total of eight (8) times for each
fibrous structure in each direction (MD and CD). The first four
strips are tested with the upper surface as the fibrous structure
was cut facing up. The last four strips are inverted so that the
upper surface as the fibrous structure was cut is facing down as
the strip is placed on the horizontal platform of the Tester.
[0204] The average overhang length is determined by averaging the
sixteen (16) readings obtained on a fibrous structure.
Overhang Length MD = Sum of 8 MD readings 8 ##EQU00002## Overhang
Length CD = Sum of 8 CD readings 8 ##EQU00002.2## Overhang Length
Total = Sum of all 16 readings 16 ##EQU00002.3## Bend Length MD =
Overhang Length MD 2 ##EQU00002.4## Bend Length CD = Overhang
Length CD 2 ##EQU00002.5## Bend Length Total = Overhang Length
Total 2 ##EQU00002.6## Flexural Rigidity = 0.1629 .times. W .times.
C 3 ##EQU00002.7##
wherein W is the basis weight of the fibrous structure in lbs/3000
ft.sup.2; C is the bending length (MD or CD or Total) in cm; and
the constant 0.1629 is used to convert the basis weight from
English to metric units. The results are expressed in mg-cm.
GM Flexural Rigidity=Square root of (MD Flexural Rigidity.times.CD
Flexural Rigidity)
11. Dry Burst
[0205] Dry burst strength is measured using a Thwing-Albert
Intelect II STD Burst Tester. 8 uu of tissue are stacked in four
groups of 2 uu. Using scissors, cut the samples so that they are
approximately 208 mm in the machine direction and approximately 114
mm in the cross-machine direction, each 2 uu thick.
[0206] Take one sample strip and place the dry sample on the lower
ring of the sample holding device with the outer surface of the
product facing up, so that the sample completely covers the open
surface of the sample holding ring. If wrinkles are present,
discard the sample and repeat with a new sample. After the sample
is properly in place on the lower ring, turn the switch that lowers
the upper ring. The sample to be tested is now securely gripped in
the sample holding unit. Start the burst test immediately at this
point by pressing the start button. The plunger will begin to rise.
At the point when the sample tears or ruptures, report the maximum
reading. The plunger will automatically reverse and return to its
original starting position. Repeat this procedure on three more
samples for a total of four tests, i.e., 4 replicates. Average the
four replicates and divide this average by two to report dry burst
per uu, to the nearest gram.
12. Wet Burst Test Method
[0207] The wet burst strength of fibrous structures and sanitary
tissue products comprising fibrous structures (collectively
referred to as "sample" or "samples" within this test method) is
determined using an electronic burst tester and specified test
conditions. The results obtained are averaged and the wet burst
strength is reported. Provisions are made for testing rapid-aged
samples as well as fresh or naturally aged samples.
Apparatus: Burst Tester--Refer to manufacturer's operation and
set-up instructions.
[0208] Note: Thwing-Albert Wet Burst Testers with an upward force
measurement yields values approximately 3-7 grams higher than
testers with a downward force measurement. This is due to the
weight of the wetted product resting on the load cell. Therefore,
the downward movement is preferred. When comparing data, the
instrument used should be noted. [0209] Calibration Weights--Refer
to manufacturer's Calibration instructions [0210] Paper
Cutter--Cutting board, 24 in. (600 mm) size [0211] Scissors--4 in.
(100 mm), or larger [0212] Pan--Approximate Width/Length/Depth: 9
in..times.12 in..times.2 in. (240.times.300.times.50 mm), or
equivalent [0213] Oven Forced draft, 221.degree. F..+-.2.degree. F.
(105.degree. C..+-.1.degree. C.) with wire shelves. Blue M or
equivalent [0214] Clamp (For use in rapid aging samples) Day
Pinchcock, Fisher Cat. No. 05-867, or equivalent [0215] Re-sealable
plastic bags--Size 26.8 cm.times.27.9 cm [0216] Distilled water at
the temperature of the conditioned room used.
Sample Preparation
[0217] For this method, a usable unit is described as one sanitary
tissue product unit regardless of the number of plies.
[0218] 1-Ply Bath Tissue: If beginning a new tissue roll the first
15 sample sheets have to be removed (to remove
Tail-Release-Gluing). Roll off 16 strips of product each 3 sample
sheets in length. It is important that the center sample sheet in
each three sample sheet strips not be stretched or wrinkled since
it is the unit to be tested. Ensure that sheet perforations are not
in the area to be tested. Stack the 3 sample sheet strips 4 high, 4
times to form your test samples.
[0219] 2-Ply/3-Ply/4-Ply Bath Tissue: If beginning a new tissue
roll, the first 15 sample sheets have to be removed (to remove
Tail-Release-Gluing). Roll off 8 strips of product each, 3 sample
sheets in length, It is important the center sample sheet in each
three sample sheet strip not be stretched or wrinkled since it is
the sample sheet to be tested. Ensure that sheet perforations are
not in the area to be tested. Stack the 3 sample sheet strips 2
high, 4 times to form your test samples.
[0220] Fresh or Naturally Aged Samples: Test prepared samples as
described under Operation. Results on freshly produced paper and
the same paper after aging for some period of time will frequently
differ.
[0221] Rapid Aging: Rapid aging of samples results in answers which
are more indicative of sample performance after aging in a
warehouse, during shipping, or in the marketplace. When required,
rapid age samples by one of the following methods, selecting the
method that is sufficient to fully age the product, this can be
established via sample aging profiles.
[0222] 5-Minute Rapid Aging: Attach a small paper clip or clamp at
the center of one of the narrow edges (perforated edge for sample;
6 in. (152.4 mm) for unconverted stock) of each sample stack: 1-ply
toilet tissue 16 sheets thick and 2-ply/3-ply/4-ply toilet tissue
eight sheets thick, a sample stack for reel samples is eight plies
thick. Suspend each sample stack by a clamp in a 221.degree.
F..+-.2.degree. F. (105.degree. C..+-.1.degree. C.) forced draft
oven for a period of five minutes.+-.10 seconds at temperature.
Remove the sample stack from the oven and cool for a minimum of 3
minutes before testing. Test the sample portions as described under
Operation.
Operation
[0223] Set-up and calibrate the Burst tester instrument according
to the manufacturer's instructions for the instrument being used.
Verify that the Burst tester program settings match those
summarized in Table 3. Remove one sample portion from the sample
stack holding the sample by the narrow edges, dipping the center of
the sample into a pan filled approximately 1 in. (25 mm) from the
top with distilled water. Leave the sample in the water for 4
(.+-.0.5) seconds. Remove and drain excess water from the sample
for 3 (.+-.0.5) seconds holding the sample in a vertical position.
Drainage allows removal of excess water for protection of the burst
tester electronics. Proceed with the test immediately after the
drain step. Ensure the sample has no perforations in the area of
the sample to be tested. Place the sample between the upper and
lower rings. Center the wet sample flatly on the lower ring of the
sample holding device. Lower the upper ring of the pneumatic
holding device to secure the sample. Start the test. The test is
over at sample failure (rupture). Record the maximum value. The
plunger will automatically reverse and return to its original
starting position. Raise the upper ring, remove and discard the
tested sample. Repeat this procedure until all samples have been
tested.
Calculations
[0224] Since some burst testers incorporate computer capabilities
that support calculations, it may not be necessary to apply the
following calculations to the test results. For example, the
Thwing-Albert EJA and Intelect II STD Burst Tester can be operated
through its menu and Program Settings options to support the
calculations required for reporting wet burst results (see Tables 2
and 3). If these capabilities are not available, then calculate the
appropriate average wet burst results as described below. The
results are reported on the basis of a single sanitary tissue
product sheet.
Wet Burst=sum of peak load readings/number of replicates tested
Deflection=sum of peak deflection readings/number of replicates
tested
Burst Energy Absorption* to peak load (BEA)=sum of peak BEA
readings/number of reps tested
[0225] *Burst Energy Absorption is the area of the stress/strain
curve between pre-tension and peak load Reporting Results
[0226] Report the Wet Burst results to the nearest gram
[0227] Report the Deflection results to the nearest 0.1 inch
[0228] Report the BEA results to the nearest 0.1 g*in/in.sup.2
TABLE-US-00002 TABLE 2 Total number of usable units (sample sheets)
tested Sample Description Total # of Load Finished Product usable
units divider Towels 4 1 Facial 8 2 Napkins 4 1 Hankies 8 2 1-Ply
Toilet Tissue 16 4 2-Ply/3-Ply/4-Ply Toilet Tissue 8 2 Handsheets 4
1 Wipes 4 1
TABLE-US-00003 TABLE 3 Burst Tester Settings for a 2000 gram load
cell Burst Tester Settings for a 2000 gram load cell Intelect II
STD Burst Tester Set Mode Manual x English/Metric English x Curve
Units Load/deflection x Compression Units Inches Load Units Grams x
Energy Units BEA x Test over Fail x Set Range 100% x At Test End
Return x Pre-Test Speed 5.00 inches/minute Test Speed 5.00
inches/minute x Start of Test Speed 5.00 inches/minute Start of
Test distance 0.100 inches Post-change-speed 5.00 inches/minute
Return Speed 20 or 40 inches/minute x Sampling Rate 20
reading/second x Gauge length 0.025 inches Adj. Gauge length
Adjusted Sample Thickness 0.025 inches Chart Device Manual
Collision Yes x Delay Time 5 seconds delay Break Sensitivity 20
grams x Size Sample See Table 2 Load divider See Table 2 Sample
Diameter 3.50 inches x Pre-Tension* 4.45 grams Sample shape
Circular
13. Panel Softness
[0229] Prior to softness testing, the paper samples to be tested
are conditioned according to Tappi Method #T402OM-88. Here, samples
are preconditioned for 24 hours at a relative humidity level of 10%
to 35% and within a temperature range of 22.degree. C. to
40.degree. C. After this preconditioning step, samples should be
conditioned for 24 hours at a relative humidity of 48% to 52% and
within a temperature range of 22.degree. C. to 24.degree. C.
[0230] The softness panel testing takes place within the confines
of a constant temperature and humidity room. If this is not
feasible, all samples, including the controls, should experience
identical environmental exposure conditions.
[0231] Softness testing is performed as a paired comparison in a
form similar to that described in "Manual on Sensory Testing
Methods", ASTM Special Technical Publication 434, published by the
American Society For Testing and Materials 1968 and is incorporated
herein by reference. Softness is evaluated by subjective testing
using what is referred to as a Paired Difference Test. The method
employs a standard external to the test material itself. For
tactile perceived softness, two samples are presented such that the
subject cannot see the samples, and the subject is required to
choose one of them on the basis of tactile softness. The result of
the test is reported in what is referred to as Panel Score Unit
(PSU).
[0232] With respect to softness testing to obtain the softness data
reported herein in PSU, a number of softness panel tests are
performed. In each test ten practiced softness judges are asked to
rate the relative softness of three sets of paired samples. The
pairs of samples are judged one pair at a time by each judge: one
sample of each pair being designated X and the other Y. Briefly,
each X sample is graded against its paired Y sample as follows:
[0233] 1. a grade of plus one is given if X is judged to may be a
little softer than Y, and a grade of minus one is given if Y is
judged to may be a little softer than X;
[0234] 2. a grade of plus two is given if X is judged to surely be
a little softer than Y, and a grade of minus two is given if Y is
judged to surely be a little softer than X;
[0235] 3. a grade of plus three is given to X if it is judged to be
a lot softer than Y, and a grade of minus three is given if Y is
judged to be a lot softer than X; and, lastly:
[0236] 4. a grade of plus four is given to X if it is judged to be
a whole lot softer than Y, and a grade of minus 4 is given if Y is
judged to be a whole lot softer than X.
[0237] The grades are averaged and the resultant value is in units
of PSU. The resulting data are considered the results of one panel
test. If more than one sample pair is evaluated then all sample
pairs are rank ordered according to their grades by paired
statistical analysis. Then, the rank is shifted up or down in value
as required to give a zero PSU value to which ever sample is chosen
to be the zero-base standard. The other samples then have plus or
minus values as determined by their relative grades with respect to
the zero-base standard. The number of panel tests performed and
averaged is such that about 0.2 PSU represents a significant
difference in subjectively perceived softness. The results of the
panel softness testing on the exemplary products produced according
to the process described herein are presented in Table 14
infra.
[0238] The results of the physical testing on the samples produced
according the process described supra and some commercially
available products are presented in Tables 4-12 provided infra.
TABLE-US-00004 TABLE 4 Exemplary Fraction Results From
Fractionation of Eucalyptus Pulp at Different Process Conditions
Effect. Width Vessels/ Vessels/ Condition (.mu.m) m g Euc Feed
118.7 6.13 100444 1 - Accepts 118.6 5.43 88979 1 - Rejects 120.6
9.23 148876 2 - Accepts 120.4 5.43 92073 2 - Rejects 120.8 8.99
138362 3 - Accepts 0.115 6.46 104198 3 - Rejects 0.125 7.88 125050
4- Accepts 120.9 4.32 70781 4- Rejects 116.6 7.39 117251
TABLE-US-00005 TABLE 5 Exemplary Physical Properties of 1-ply
Commercially Available and Products Produced According to the
Process Described Herein Total Dry Dry Basis Dry Tensile Tensile
Elongation Elongation Peak TEA- Peak TEA- Weight Tensile CD MD CD
MD CD MD (lb/3000 ft.sup.2) (g/in) (g/in) (g/in) (%) (%)
(g*in/in.sup.2) (g*in/in.sup.2) Charmin Basic 19.5 697 225 472 3.52
18.71 6.19 43.95 Scott 1000 11 690 204 486 5.9 22.6 7.6 59 Scott
Extra Soft 18.38 540 173 367 13.9 12.6 11.4 23.7 Kroger PL 12.62
411.5 107.5 304 8.76 18.42 5.35 30.05 New product BASE 15.76 297.7
89.3 208.3 9.27 27.87 4.77 27.90 Not Embossed TEST 1 Not Embossed
15.41 233.0 66.0 167.0 11.10 21.50 4.27 18.57 TEST 2 Not Embossed
15.28 227.3 66.3 161.0 12.26 24.83 4.93 20.40 TEST 3 Not Embossed
15.77 290.0 95.0 195.0 9.50 25.93 5.10 25.40
TABLE-US-00006 TABLE 6 Exemplary Physical Properties of 1-ply
Commercially Available and Products Produced According to the
Process Described Herein Dry Modulus Total Wet Wet Dry CD Dry MD
Geo. Wet Tensile Tensile % % Modulus Modulus Mean Tensile CD MD
Elongation Elongation (g/cm %) (g/cm %) (g/cm %) (g/in) (g/in)
(g/in) CD Wet MD Wet Charmin Basic 1216.5 1224.25 1220.4 58 26 32
2.09 5.31 Scott 1000 2152 1442 1761.6 12.63 3.69 8.94 2.6 Scott
Extra Soft 424 1177 706.4 12.42 4.25 8.17 5.45 Kroger PL 606.5
768.67 682.8 12.55 3.38 9.17 6.62 New product BASE Not Embossed
489.33 308.00 388.2 24.33 7.33 17.00 4.13 6.43 TEST 1 Not Embossed
284.33 360.00 319.9 31.33 9.00 22.33 6.13 7.67 TEST 2 Not Embossed
274.33 280.00 277.2 27.67 8.00 19.67 5.43 7.70 TEST 3 Not Embossed
510.67 336.00 414.2 37.33 12.00 25.33 6.97 8.87
TABLE-US-00007 TABLE 7 Exemplary Physical Properties of 1-ply
Commercially Available and Products Produced According to the
Process Described Herein Peak Peak Wet TEA - TEA - Wet Wet Modulus
CD Wet MD Wet CD MD Geo. (g*in/ (g*in/ Modulus Modulus Mean
in.sup.2) in.sup.2) (g/cm %) (g/cm %) (g/cm %) Charmin Basic 0.53
1.63 52.5 75.25 62.9 Scott 1000 0.42 16.1 Scott Extra 0.72 20.7
Soft Kroger PL 6.62 11.83 New product 0.53 0.93 9.67 19.00 13.6
BASE Not Embossed TEST 1 Not 0.67 1.27 12.67 27.00 18.5 Embossed
TEST 2 Not 0.67 1.17 9.67 22.00 14.6 Embossed TEST 3 Not 0.83 1.53
19.00 28.67 23.3 Embossed
TABLE-US-00008 TABLE 8 Exemplary Physical Properties of 2-ply
Commercially Available and Products Produced According to the
Process Described Herein Total Dry Dry Basis Dry Tensile Tensile
Weight Caliper Tensile CD MD % CD % MD (lb/3000 ft.sup.2) (mil)
(g/in) (g/in) (g/in) Elongation Elongation Charmin Ultra Soft 31.22
23.51 531.5 174.56 356.94 11.69 25.67 Charmin Ultra Strong 24.81
21.01 747.4 253.75 493.69 12.16 18.83 Cottonelle Clean Care 25.9
23.4 557 191 366 9.6 14.9 Cottonelle Ultra Comfort Care 28.2 23.8
707 218 489 12 11.7 Cottonelle Gentle Care 25.49 21.4 533 195 338
8.1 14 Quilted Northern Ultra Soft & Strong 28.17 20.8 522 179
343 9 24.3 Angel Soft 24.54 18.6 530 148 382 10 27 Kirkland
Signature 23.7 12 554 153 401 7 23 Kirkland Signature Ultra Soft
28.97 18.3 746.3 275.5 470.8 8 17.9 Members Mark 25.2 19.6 656 233
423 7.9 14.9 White Cloud Ultra Soft and Thick 31.04 17.8 820 211.5
608.5 8.16 17.38 White Cloud Ultra Strong and Soft 26.4 18.4 879
326 553 7.1 24.1 Great Value Ultra Soft 26.55 20 693 237 456 7.3
14.7 Great Value Ultra Strong 24.4 20 776 283 493 7.4 16.1 CVS
Total Home Ultra Soft 25.08 21.2 730.6 272.8 457.8 9 16.7 Kroger
Ultra Strong 25.9 21.1 735 288 447 6.8 22 Kroger Ultra Soft 31 22
712 268 444 7 24.5 Target Up & Up Ultra Soft 27.83 21.3 586
214.6 371.4 8 18.3 Target Up & Up Soft 27.08 16.55 662.5 205
457.5 7.56 19.13 CVS Total Home Soft and Strong 22.91 19.8 613.5
167 446.5 7.94 14.83 New product BASE Embossed 30.45 21.57 587.7
195.7 392.0 11.38 28.03 TEST 1 Embossed 30.04 21.03 549.0 168.0
381.0 11.55 24.33 TEST 2 Embossed 29.80 20.87 544.0 165.7 378.3
11.44 25.47 TEST 3 Embossed 30.42 20.97 556.7 178.3 378.3 10.53
25.07 New product BASE Not Embossed 31.37 21.93 597.3 201.3 396.0
10.57 30.60 TEST 1 Not Embossed 30.80 21.43 549.7 177.0 372.7 10.95
28.17 TEST 2 Not Embossed 30.99 21.47 529.0 173.0 356.0 10.93 27.43
TEST 3 Not Embossed 31.17 22.60 569.0 195.0 374.0 10.17 29.03
TABLE-US-00009 TABLE 9 Exemplary Physical Properties of 2-ply
Commercially Available and Products Produced According to the
Process Described Herein Dry Total Wet Wet Peak TEA- Peak TEA- Dry
CD Dry MD Modulus Wet Tensile Tensile CD MD Modulus Modulus Geo.
Mean Tensile CD MD (g*in/in.sup.2) (g*in/in.sup.2) (g/cm %) (g/cm
%) (g/cm %) (g/in) (g/in) (g/in) Charmin Ultra Soft 11.12 48.30
715.31 759.13 736.9 55.1 18.00 37.13 Charmin Ultra Strong 16.78
50.13 909.38 1383.69 1121.7 63.3 21.50 41.75 Cottonelle Clean Care
8.3 27 708 913 804.0 32.9 11.9 21 Cottonelle Ultra Comfort Care
12.96 28 682 1313 946.3 32.2 10.9 21.3 Cottonelle Gentle Care 8.5
25 836.4 973.6 902.4 49.55 17.1 32.45 Quilted Northern Ultra Soft
& Strong 9.5 40 1095 531 762.5 46.5 16.5 30 Angel Soft 9 59 921
884 902.3 27.34 7.64 19.7 Kirkland Signature 7 55 1080 814 937.6 35
9 26 Kirkland Signature Ultra Soft 12.6 36.5 1896.3 766 1205.2
49.75 18.85 30.9 Members Mark 9.9 28.8 1366 980 1157.0 15.7 6.1 9.6
White Cloud Ultra Soft and Thick 10.85 54.85 1521.5 1371.5 1444.6
16.75 5 11.75 White Cloud Ultra Strong and Soft 13.5 56.5 2270 685
1247.0 60.9 22.9 38 Great Value Ultra Soft 9.5 31 1551 1085 1297.2
19.9 7.6 12.3 Great Value Ultra Strong 11.7 36.1 1741 1040 1345.6
22.5 8.9 13.6 CVS Total Home Ultra Soft 13.9 33.4 1791 1057 1375.9
24.55 9.85 14.7 Kroger Ultra Strong 11 44 1934 639 1111.7 18 7.5
10.5 Kroger Ultra Soft 10.6 49 1897 602.8 1069.4 18.3 7.4 10.9
Target Up & Up Ultra Soft 10.1 32.9 1386.4 668 962.3 45.65
15.65 30 Target Up & Up Soft 8.68 45.5 1377.25 1047 1200.8
24.25 7.75 16.5 CVS Total Home Soft and Strong 8.35 34.75 1194.75
1148.75 1171.5 15 4.25 10.75 New product BASE Embossed 13.27 56.20
895.33 699.00 791.1 52.67 16.33 36.33 TEST 1 Embossed 11.70 47.50
761.33 766.67 764.0 55.67 17.33 38.33 TEST 2 Embossed 11.67 49.03
793.67 715.00 753.3 54.67 15.67 39.00 TEST 3 Embossed 11.43 48.30
922.67 746.33 829.8 60.00 18.00 42.00 New product BASE Not Embossed
12.60 61.67 990.33 656.00 806.0 51.67 16.67 35.00 TEST 1 Not
Embossed 11.40 52.50 816.67 632.33 718.6 58.33 19.33 39.00 TEST 2
Not Embossed 11.40 50.60 850.67 680.33 760.7 56.33 18.67 37.67 TEST
3 Not Embossed 12.17 56.53 1064.67 687.00 855.2 64.33 20.33
44.00
TABLE-US-00010 TABLE 10 Exemplary Physical Properties of 2-ply
Commercially Available and Products Produced According to the
Process Described Herein Elongation Elongation Peak TEA- Peak TEA-
Wet CD Wet MD Wet Modulus CD Wet MD Wet CD Wet MD Wet Modulus
Modulus Geo. Mean (%) (%) (g*in/in.sup.2) (g*in/in.sup.2) (g/cm %)
(g/cm %) (g/cm %) Charmin Ultra Soft 11.53 12.05 1.67 2.63 23.00
68.69 39.7 Charmin Ultra Strong 11.51 11.67 1.86 2.78 30.88 126.63
62.5 Cottonelle Clean Care 6.02 10.9 0.75 1.6 23.6 35 28.7
Cottonelle Ultra Comfort Care 6.5 9.5 0.77 1.4 18.1 40 26.9
Cottonelle Gentle Care 7.9 13.7 1.13 2.76 31.35 59.5 43.2 Quilted
Northern Ultra Soft & Strong 10 16.5 1.4 2.9 20.8 41 29.2 Angel
Soft 6.33 6.9 0.74 1.4 15 21.3 17.9 Kirkland Signature 5 7 1 1 18
36 25.5 Kirkland Signature Ultra Soft 8.91 7.26 1.33 1.49 35.2 47.3
40.8 Members Mark 3.1 3.1 2 0.78 11.7 19.2 15.0 White Cloud Ultra
Soft and Thick 0.9 0.4 24 White Cloud Ultra Strong and Soft 9.2
7.78 1.6 1.8 42.96 160 82.9 Great Value Ultra Soft 2.8 4.2 0.4 0.6
18.1 25.2 21.4 Great Value Ultra Strong 3.7 4.9 0.45 0.91 20.8 25.2
22.9 CVS Total Home Ultra Soft 5.28 5.22 0.73 0.73 18.8 28.95 23.3
Kroger Ultra Strong 2.8 3.8 0.83 0.28 18.5 16.9 17.7 Kroger Ultra
Soft 2.6 3.75 0.59 0.58 18.5 15.44 16.9 Target Up & Up Ultra
Soft 7.68 7.92 1.03 1.55 28.2 45.65 35.9 Target Up & Up Soft
7.58 2.3 7.58 0.65 7.75 29.5 15.1 CVS Total Home Soft and Strong
2.85 0.43 16.75 New product BASE Embossed 9.83 10.23 1.40 2.30
20.00 68.00 36.9 TEST 1 Embossed 10.47 10.47 1.50 2.47 20.33 99.67
45.0 TEST 2 Embossed 9.50 10.77 1.33 2.43 18.33 105.33 43.9 TEST 3
Embossed 10.13 11.17 1.50 2.60 21.33 150.00 56.6 New product BASE
Not Embossed 9.73 11.07 1.37 2.33 21.00 63.33 36.5 TEST 1 Not
Embossed 10.93 11.73 1.70 2.63 23.00 122.00 53.0 TEST 2 Not
Embossed 11.17 11.40 1.70 2.57 23.33 69.00 40.1 TEST 3 Not Embossed
10.80 11.53 1.67 2.80 26.67 195.67 72.2
TABLE-US-00011 TABLE 11 Exemplary Physical Properties of 2-ply
Commercially Available and Products Produced According to the
Process Described Herein Horizontal Vertical Horizontal Vertical
Wet Wet Absorbent Absorbent Absorbent Absorbent Decay Decay
Capacity Capacity Capacity Capacity Lint CD 30 MD 30 (g/sheet)
(g/sheet) (g/g) (g/g) (avg) Charmin Ultra Soft 11.47 22.06 6.37
12.23 6.9 Charmin Ultra Strong 9.61 23.18 5.44 13.10 4.6 Cottonelle
Clean Care 6.9 3.77 16.47 9 5.45 Cottonelle Ultra Comfort Care 10
5.2 21.5 11.2 3.8 Cottonelle Gentle Care 8.7 17.75 Quilted Northern
Ultra Soft & Strong 8 4.5 17 9.5 5 Angel Soft 6.8 3.24 16.56
7.8 3.4 Kirkland Signature 6 3 14 7 3 Kirkland Signature Ultra Soft
10.2 17.65 10 6 18 10 8 Members Mark 8.2 4.8 18.1 10.7 5 White
Cloud Ultra Soft and Thick 8.25 4.45 15.7 8.48 2.35 White Cloud
Ultra Strong and Soft 7.4 4.4 16.4 9.6 4.2 Great Value Ultra Soft 8
4.7 18 10.6 6 Great Value Ultra Strong 8.1 4.5 19.8 11.02 4.2 CVS
Total Home Ultra Soft 4.7 7.85 9 4 16 9 6 Kroger Ultra Strong 7.9
4.5 18.5 10.6 4 Kroger Ultra Soft 8.9 5.2 17.2 10.1 6.5 Target Up
& Up Ultra Soft 6.7 11.1 9 5 16 8 7 Target Up & Up Soft
6.95 3.53 15.85 8 5.23 CVS Total Home Soft and Strong 7.6 3.05 14.8
6.03 2.95 New product BASE Embossed 5.67 10.67 12.17 6.53 23.77
12.73 9.83 TEST 1 Embossed 5.67 11.33 12.13 6.17 24.17 12.27 10.20
TEST 2 Embossed 5.00 10.00 11.87 5.93 23.40 11.77 10.23 TEST 3
Embossed 6.33 12.00 11.73 6.23 23.07 12.27 9.40 New product BASE
Not Embossed 5.67 10.33 11.93 6.20 22.90 11.87 10.73 TEST 1 Not
Embossed 6.33 10.00 11.90 6.37 23.30 12.43 9.93 TEST 2 Not Embossed
6.33 11.33 10.53 6.30 20.40 12.20 10.77 TEST 3 Not Embossed 6.67
11.67 10.37 6.27 19.90 12.03 9.43
TABLE-US-00012 TABLE 12 Exemplary Physical Properties of 2-ply
Commercially Available and Products Produced According to the
Process Described Herein Wet Burst Dry Burst Flexural (g) (g)
Rigidity Charmin Ultra Soft 43 264 Charmin Ultra Strong 33 371
Cottonelle Clean Care 16 242 Cottonelle Ultra Comfort Care 18 333
135 Cottonelle Gentle Care 226 81 Quilted Northern Ultra Soft &
Strong 26 217 Angel Soft 18.57 221 Kirkland Signature 14 176
Kirkland Signature Ultra Soft 21 243.7 Members Mark 5.9 249 White
Cloud Ultra Soft and Thick 3 268.25 White Cloud Ultra Strong and
Soft 28.1 254 Great Value Ultra Soft 6.4 243 Great Value Ultra
Strong 8.6 284 CVS Total Home Ultra Soft 10 266.4 165 Kroger Ultra
Strong 6.9 253 Kroger Ultra Soft 6.8 228 Target Up & Up Ultra
Soft 20 239.2 Target Up & Up Soft 7.5 242.75 CVS Total Home
Soft and Strong 4.25 205 New product BASE Embossed 28.33 277.3
131.0 TEST 1 Embossed 32.67 249.7 112.1 TEST 2 Embossed 32.33 233.7
112.6 TEST 3 Embossed 34.67 259.7 112.9 New product BASE Not
Embossed 26.33 263.7 156.8 TEST 1 Not Embossed 32.00 256.0 143.9
TEST 2 Not Embossed 29.00 259.0 123.1 TEST 3 Not Embossed 32.33
257.0 144.7
TABLE-US-00013 TABLE 13 Emtec Softness Data Results for 2-ply Test
Products TEST 1B TEST 1B TEST 1A Not TEST 2 TEST 1A Embossed TEST 2
Not Embossed Not Embossed Accepts on Embossed BASE Embossed Accepts
on Embossed BASE Accepts WS Rejects Accepts Not Accepts WS Rejects
Accepts Embossed on WS at F/C on WS Embossed on WS at F/C on WS (dB
V.sup.2 rms) (dB V.sup.2 rms) (dB V.sup.2 rms) (dB V.sup.2 rms) (dB
V.sup.2 rms) (dB V.sup.2 rms) (dB V.sup.2 rms) (dB V.sup.2 rms) T57
6.69 6.03 5.87 6.54 6.32 5.79 6.00 6.50 T5750 33.2 33.3 32.3 31.2
30.7 30.5 29.9 27.3
TABLE-US-00014 TABLE 14 Panel Softness Data Results for 2-ply Test
Products TEST 1B TEST 1B Embossed TEST 1A Not TEST 2 TEST 1A
Accepts TEST 2 Not Embossed Not Embossed on WS Embossed BASE
Embossed Accepts on Embossed BASE Accepts Rejects Accepts Not
Accepts WS Rejects Accepts Embossed on WS at F/C on WS Embossed on
WS at F/C on WS -- 0.45 0.78 0.33 -- 0.33 0.68 0.39
[0239] As provided in Tables 4-14 above, the exemplary new and
unique test products developed by the fractionation process
described herein are identified and provided as follows:
BASE (Embossed)-Outer (Eucalyptus feed pulp)/Inner (Eucalyptus feed
pulp+softwood (NSK))
TEST 1 (Embossed) Outer (Eucalyptus Accepts 1)/Inner (Eucalyptus
feed pulp+softwood (NSK))
TEST 2 (Embossed) Outer (Eucalyptus Accepts 1)/Inner (Eucalyptus
rejects 1+softwood (NSK))
TEST 3 (Embossed) Outer (Eucalyptus Accepts 2)/Inner (Eucalyptus
feed pulp+softwood (NSK))
BASE (Not Embossed) Outer (Eucalyptus feed pulp)/Inner (Eucalyptus
feed pulp+softwood (NSK))
TEST 1 (Not Embossed) Outer (Eucalyptus Accepts 1)/Inner
(Eucalyptus feed pulp+softwood (NSK))
TEST 2 (Not Embossed) Outer (Eucalyptus Accepts 1)/Inner
(Eucalyptus rejects 1+softwood (NSK))
TEST 3 (Not Embossed) Outer (Eucalyptus Accepts 2)/Inner
(Eucalyptus feed pulp+softwood (NSK))
where:
[0240] 1=the first stage of a two-stage fractionation process is
provided with process settings that provide a pressure drop of
about 25.3 psi and the second stage is provided with process
settings that provide a pressure drop of about 26.5 psi; and,
[0241] 2=the first stage of a two-stage fractionation process is
provided with process settings that provide a pressure drop of
about 27.6 psi and the second stage is provided with process
settings that provide a pressure drop of about 26.5 psi.
[0242] FIG. 9 provides a photomicrograph of an exemplary prior art
consumer product. This photomicrograph provides a magnified view of
the surface structure of the exemplary prior art consumer product
having both fibers 12 and vessel 14 elements. As can be seen the
surface structure of the exemplary prior art consumer product shows
a significant number of vessel 14 elements embedded on the surface
and within the surface of the exemplary prior art consumer product.
This exemplary product exhibits the currently understood
softness/strength dynamic discussed supra. In other words, the
overall softness of the resulting product has a direct effect on
the overall strength of the consumer product.
[0243] FIG. 10 provides a photomicrograph of an exemplary consumer
product made by an exemplary papermaking process and incorporating
pulp fibers hydrocyclonically treated according to the process
described herein in an effort to minimize the presence of vessels
14 present in certain layers of the resulting consumer product.
This photomicrograph provides a magnified view of the surface
structure of the exemplary consumer product having fibers 12. As
can be seen, the surface structure of the exemplary product shows a
significantly reduced number of vessel 14 elements embedded on the
surface and within the surface of the exemplary prior art consumer
product.
[0244] As shown in Tables 13-14, the product resulting from the
fractionation process described herein exhibits the exemplary
properties provided supra and changes the currently understood
softness/strength dynamic discussed supra. In other words, the
product produced according to the techniques disclosed herein can
be provided in a manner that turns the currently understood
softness/strength rubric on its head. It is now possible to provide
a product that exhibits significant strength yet can be appreciated
by the consumer to have heretofore unrealizable softness. This is
clearly a consumer desirable attribute that has clearly not been
realizable until now. As evidenced by the tabulated data, there is
a strong correlation in the objective physical properties related
to softness (e.g., TS7, TS750) as measured by the techniques
discussed supra in the products produced by the fractionation
process described herein and the subjective results of the panel
softness study (PSU). There is also concrete evidence in the
strength-related objective measurements of the products produced by
the fractionation process described herein and the objective
physical properties related to softness.
[0245] The BASE embossed and not embossed products and the 6 test
product configurations (i.e., Test 1-3 embossed and not embossed)
are shown schematically in FIGS. 11-14. As shown, the outer layer
of each ply of each Test two-ply substrate can be formed from an
aqueous slurry of eucalyptus (Brazilian bleached hardwood kraft
pulp) feed pulp fibers treated by a two-stage fractionation process
comprising product stream "accepts" having a lower percentage of
vessels than the feed pulp. The inner layer of each ply of a
two-ply substrate can be formed from either an aqueous slurry of
feed pulp fibers treated by a two-stage fractionation process
comprising the product stream "rejects" having a higher percentage
of vessels than the feed pulp or un-fractionated feed pulp. It
should be understood by one of skill in the art that the resulting
two-ply products can comprise outer layers of "accepts" and inner
layers of "rejects" and/or untreated pulp material.
[0246] FIG. 11 shows a schematic view of the BASE embossed and not
embossed products. The outer layer of each ply can be formed from
an aqueous slurry of eucalyptus (Brazilian bleached hardwood kraft
pulp) un-fractionated feed pulp fibers. The inner layer can be
formed from a combination of an aqueous slurry of eucalyptus
(Brazilian bleached hardwood kraft pulp) un-fractionated feed pulp
fibers and NSK fibers.
[0247] FIG. 12 shows a schematic view of the Test 1 product
comprising a two-ply substrate wherein each ply provides an outer
layer comprising "accepts." The first stage of an exemplary
two-stage fractionation process is provided with process settings
that provide a pressure drop of about 25.3 psi and the second stage
is provided with process settings that provide a pressure drop of
about 26.5 psi. The inner layer can be formed from an aqueous
slurry comprising a combination of eucalyptus (Brazilian bleached
hardwood kraft pulp) un-fractionated feed pulp fibers and NSK
fibers.
[0248] FIG. 13 shows a schematic view of the Test 2 product
comprising a two-ply substrate wherein each ply provides an outer
layer comprising "accepts." The first stage of an exemplary
two-stage fractionation process that produces the accepts is
provided with process settings that provide a pressure drop of
about 25.3 psi and the second stage is provided with process
settings that provide a pressure drop of about 26.5 psi. The inner
layer of each ply comprises a combination of "rejects" and NSK
fibers. The first stage of an exemplary two-stage fractionation
process is provided with process settings that provide a pressure
drop of about 25.3 psi and the second stage is provided with
process settings that provide a pressure drop of about 26.5
psi.
[0249] FIG. 14 shows a schematic view of the Test 3 product
comprising a two-ply substrate wherein each ply provides an outer
layer comprising "accepts." The first stage of a two-stage
fractionation process is provided with process settings that
provide a pressure drop of about 27.6 psi and the second stage is
provided with process settings that provide a pressure drop of
about 26.5 psi. The inner layer can be formed from an aqueous
slurry comprising a combination of eucalyptus (Brazilian bleached
hardwood kraft pulp) un-fractionated feed pulp fibers and NSK
fibers.
[0250] As can be seen in FIG. 15, a plot of the geometric mean of
wet modulus versus the geometric mean of dry modulus for six, 1-ply
test product configurations (i.e., Test 1-3 embossed and not
embossed) data provided in Tables 5-7, infra, provides an equation
represented by:
Geometric Mean Wet Tensile Modulus>0.06*Geometric Mean Dry
Tensile Modulus-9.5
[0251] As can be seen in FIG. 16, a plot of the geometric mean of
wet modulus versus the geometric mean of dry modulus for six, 2-ply
test product configurations (i.e., Test 1-3 embossed and not
embossed) data provided in Tables 8-12, infra, provides an equation
represented by:
Geometric Mean Wet Tensile Modulus>0.087*Geometric Mean Dry
Tensile Modulus-24.3
Additional Examples
[0252] a. A process for manufacturing a web material, the process
comprising the steps of: [0253] a) providing a pulp material
comprising fibers and vessels; [0254] b) separating said vessels
from said fibers in said pulp material to form a slurry having at
least about 7 percent less vessels per meter than said pulp
material; [0255] c) processing said slurry to form said web
material.
[0256] b. The process of a. further comprising the step of
separating said vessels from said fibers with a hydrocyclone.
[0257] c. The process of any of a. through b. wherein said step b)
further comprises the step of creating an accepts stream and a
rejects stream, said accepts stream having less vessels than said
rejects stream.
[0258] d. The process of c. further comprising the step of
separating said vessels from said fibers in said rejects stream to
form a slurry having at least about 7 percent less vessels than
said rejects stream.
[0259] e. The process of c. further comprising the step of
processing said rejects stream to create a second accepts stream
and a second rejects stream, said second accepts stream having less
vessels than said second rejects stream.
[0260] f. The process of e. further comprising the step of adding
said second accepts stream to said slurry.
[0261] g. The process of any of a. through f. wherein said step c)
further comprises the step of depositing said slurry on a
foraminous forming wire.
[0262] h. The process of g. further comprising the step of
dewatering said slurry disposed upon said foraminous forming wire
to a fiber consistency ranging from about 40 percent to about 80
percent.
[0263] i. The process of h. further comprising the step of
transferring said dewatered slurry to a foraminous forming
member.
[0264] j. The process of i. further comprising the step of
dewatering said slurry disposed upon said foraminous forming
member.
[0265] k. The process of j. further comprising the step of
transferring said dewatered slurry from said foraminous forming
member to a surface of a through air dryer.
[0266] l. The process of k. further comprising the step of creping
said dewatered slurry from said surface of said through air dryer
to form said web material.
[0267] m. The process of l. further comprising the step of winding
said web material.
[0268] n. A process for manufacturing a papermaking slurry, said
process comprising the steps of: [0269] a) providing a pulp
material comprising fibers and vessels; [0270] b) separating said
vessels from said fibers in said pulp material to form said
papermaking slurry having at least about 7 percent less vessels per
meter than said pulp material.
[0271] o. The process of n. wherein said step b) further comprises
the step of separating said vessels from said fibers with a
hydrocyclone.
[0272] p. The process of any of n. through o. wherein said step of
separating said vessels from said fibers in said pulp material
further comprises the step of creating accepts stream and a rejects
stream, said accepts stream having less vessels than said rejects
stream.
[0273] q. The process of any of n. through p. further comprising
the step of separating said vessels from said fibers in said
rejects stream to form a slurry having at least about 7 percent
less vessels than said rejects stream.
[0274] r. A process for manufacturing a papermaking slurry, said
process comprising the steps of: [0275] a) providing a pulp
material comprising fibers; [0276] b) separating fibers having an
average width of at less than about 50 .mu.M from said pulp
material; [0277] c) forming said papermaking slurry from said
separated fibers.
[0278] s. The process of r. wherein said step b) further comprising
the step of separating said fibers with a hydrocyclone.
[0279] t. The process of any of r. through s. wherein said step of
separating said fibers with a hydrocyclone further comprises the
step of creating accepts stream and a rejects stream, said accepts
stream having more fibers having an average width of at less than
about 50 .mu.M.
[0280] u. A single ply web material formed from a pulp material and
comprising a first layer and a second layer, said first layer
having at least about 7 percent less vessels per meter than said
pulp material.
[0281] v. The single ply web material of u. wherein said web
material has a Geometric Mean Wet Tensile Modulus>0.06*Geometric
Mean Dry Tensile Modulus-9.5.
[0282] w. The single ply web material of any of u. through v.
wherein said web material is not embossed.
[0283] x. The single ply web material of any of u. through w.
wherein said web material has a total dry tensile value of less
than 290 Win.
[0284] y. The single ply web material of any of u. through x.
wherein said web material has a CD wet elongation value of greater
than 4.13%.
[0285] z. The single ply web material of any of u. through y.
wherein said Geometric Mean Wet Tensile Modulus is less than
23.3.
[0286] aa. The single ply web material of any of u. through z.
wherein said web material has a CD wet peak TEA value of greater
than 0.53 g*in/in.sup.2.
[0287] bb. The single ply web material of any of u. through aa.
wherein said web material has a MD wet peak TEA value of greater
than 0.93 g*in/in.sup.2.
[0288] cc. The single ply web material of any of u. through bb.
wherein said web material has a CD dry tensile value of less than
95.0 g/in.
[0289] dd. The single ply web material of any of u. through cc.
wherein said web material has a MD dry tensile value of less than
208.3 g/in.
[0290] ee. A multiple ply web material formed from a first ply
formed from a pulp material and comprising a first layer and a
second layer, said first layer having at least about 7 percent less
vessels per meter than said pulp material.
[0291] ff. The multiple ply web material of ee. wherein said web
material has a Geometric Mean Wet Tensile
Modulus>0.087*Geometric Mean Dry Tensile Modulus-24.3.
[0292] gg. The multiple ply web material of any of ee. through ff.
wherein said web material has a total dry tensile value of less
than 587.7 g/in.
[0293] hh. The multiple ply web material of any of ee. through gg.
wherein said web material has a CD wet elongation value of greater
than 9.5%.
[0294] ii. The multiple ply web material of any of ee. through hh.
wherein said Geometric Mean Wet Tensile Modulus is less than
56.6.
[0295] jj. The multiple ply web material of any of ee. through ii.
wherein said web material has a CD wet peak TEA value of greater
than 1.33 g*in/in.sup.2.
[0296] kk. The multiple ply web material of any of ee. through jj.
wherein said web material has a MD wet peak TEA value of greater
than 2.33 g*in/in.sup.2.
[0297] ll. The multiple ply web material of any of ee. through kk.
wherein said web material has a CD dry tensile value of less than
201.3 g/in.
[0298] mm. The multiple ply web material of any of ee. through ll.
wherein said web material has a MD dry tensile value of less than
396.0 g/in.
[0299] nn. The multiple ply web material of any of ee. through mm
wherein said web material has a TS7 value of greater than 5.79 db
V.sup.2 rms.
[0300] oo. The multiple ply web material of any of ee. through nn.
wherein said web material is embossed.
[0301] pp. The multiple ply web material of oo. wherein said web
material has a TS7 value of greater than 5.87 db V.sup.2 rms.
[0302] qq. The multiple ply web material of any of ee. through pp
wherein said web material is creped.
[0303] rr. The multiple ply web material of any of ee. through nn.
wherein said web material is not embossed.
[0304] ss. The multiple ply web material of qq. wherein said web
material has a TS7 value of greater than 5.79 db V.sup.2 rms.
[0305] tt. The multiple ply web material of any of ee. through ss.
wherein said first layer is formed from a slurry wherein said
slurry is formed from a pulp comprising separated fibers having an
average width of at less than about 50 .mu.M.
[0306] uu. The multiple ply web material of any of ee. through tt.
wherein said web material is creped.
[0307] vv. The multiple ply web material of any of ee. through uu.
wherein said web material is through air dried.
[0308] ww. The multiple ply web material of any of ee. through vv.
wherein said web material is selected from the group consisting of
paper towel, bath tissue, and facial tissue.
[0309] xx. The single ply web material of any of u. through dd.
wherein said first layer is formed from a slurry wherein said
slurry is formed from a pulp comprising separated fibers having an
average width of at less than about 50 .mu.M.
[0310] yy. The multiple ply web material of any of u. through dd.
wherein said web material is creped.
[0311] zz. The multiple ply web material of any of u. through dd.
and ww. through yy. wherein said web material is through air
dried.
[0312] aaa. The multiple ply web material of any of u. through dd.
and ww. through zz. wherein said web material is selected from the
group consisting of paper towel, bath tissue, and facial
tissue.
[0313] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm."
[0314] Every document cited herein, including any cross referenced
or related patent or application and any patent application or
patent to which this application claims priority or benefit
thereof, is hereby incorporated herein by reference in its entirety
unless expressly excluded or otherwise limited. The citation of any
document is not an admission that it is prior art with respect to
any invention disclosed or claimed herein or that it alone, or in
any combination with any other reference or references, teaches,
suggests or discloses any such invention. Further, to the extent
that any meaning or definition of a term in this document conflicts
with any meaning or definition of the same term in a document
incorporated by reference, the meaning or definition assigned to
that term in this document shall govern.
[0315] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *