Note: Descriptions are shown in the official language in which they were submitted.
1
COFORMING PROCESSES AND FORMING BOXES USED THEREIN
FIELD OF THE INVENTION
The present invention relates to coforming processes for commingling two or
more
materials, for example solid additives, for example fibers and/or
particulates, and filaments, and
equipment; namely, forming boxes, useful in such coforming processes and more
particularly to
coforming processes for commingling filaments with one or more fibers, such as
pulp fibers, and
forming boxes useful therein.
BACKGROUND OF THE INVENTION
Forming boxes have been used in the past to facilitate the commingling
("coforming") of
two or more materials such as filaments and fibers during a fibrous structure
making process.
However, the known forming boxes were designed to have one material, for
example pulp fibers,
being injected into another material, for example filaments, in a
perpendicular fashion (90 to one
another) as shown in Prior Art Fig. 1. The prior art forming box (coform box)
10 shown in Fig. 1
has a first material inlet 12 and a second material inlet 14. Filaments 16
from a filament source
18, such as a die, enter the coform box 10 through the first material inlet
12. Pulp fibers 20 from
a fiber source 22, such as a fiber spreader, in fluid communication with a
hammermill 24 enter the
coform box 10 through the second material inlet 14. The pulp fibers 20 contact
the filaments 16
inside the coform box 10 in a perpendicular fashion, in other words at an
angle p of 90 from one
side ("single-sided injection"). One problem with these known forming boxes
used in coforming
processes is that the 90 angle at which the two materials (filaments and pulp
fibers) impact one
another creates instability in the air jet transporting the filaments 16
because the air jet transporting
the pulp fibers 20 feeds more air into the air jet transporting the filaments
16 than it wants to entrain
thus resulting in instability in the air jet transporting the filaments 16,
which ultimately leads to
poor formation of the fibrous structure 26 being collected on the belt 28. In
an arrangement in
which the angle 1 is close to 90 , any CD variation in velocity of the second
material, such as pulp
fibers 20, entering the coform box through the second material inlet 14 will
have a large effect on
the pulp fibers 20 and the subsequent CD weight distribution of the pulp
fibers 20 in the resulting
fibrous structure 26.
In addition to the known coforming processes that utilize the known forming
boxes, there
are known coforming processes that do not utilize a forming box as shown in
Prior Art Figs. 2 and
3. In one example as shown in Prior Art Fig. 2, a known coforming process
commingles filaments
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16 from a filament source 18, such as a die, with pulp fibers 20, from a fiber
source 22, such as a
picker roll, by injecting a single stream of the pulp fibers 20 into the
intersection of two streams of
filaments 16 in an open, non-enclosed, non-controlled environment (i.e., not
within a forming box).
The problems with this coforming process are since this geometry is not
constrained within a
forming box, the air flows exhibited will be constrained by the various jets'
ability to naturally
entrain air through physics. Any increase in airflow from the pulp fibers 20
beyond what can be
entrained by the filaments 16 will result in a local high pressure zone at the
intersection of the
respective jets, causing hygiene issues in the production of the substrate.
In addition, since the lack of the forming box limits the amount of air that
can be used, it
also limits the speed with which heat can be taken out of the various streams.
The current invention
discloses the addition of air at greater than the natural ability of the jet
to entrain, as well as the
introduction of liquid water, both of which result in more rapid removal of
heat from the jet.
Prior Art Fig. 3 shows an example of another known coforming process that
commingles
filaments 16 with pulp fibers 20 by injecting a single stream of pulp fibers
20, from a fiber source
22, such as a picker roll, into one side ("single-sided injection") of a
single stream of filaments 16
from a filament source 18, such as a die, at a angle of 90 in an open, non-
enclosed, non-controlled
environment (i.e., not within a forming box). The problems with this coforming
process are 1) it
relies more heavily on the natural entrainment from room air to quench the
polymer forming the
filaments, for example polypropylene; 2) the 90 introduction of pulp to the
melt results in jet
instability and CD control issues, especially at higher JARS; and 3) heat
transfer issues associated
with the natural entrainment limitation and lack of liquid water.
As seen above, a problem with existing coforming processes is that the
formation of a
fibrous structure made from the coforming process, even when a known forming
box is used in the
process, needs improved due to multiple (and sometimes contradictory)
requirements on what must
occur in the coform box in order to meet consumer desires. These requirements
include, but are
not limited to:
1. Maximizing jet stability at all mass ratios of the streams (JAR).
2. Minimizing zones of stalls and/or separated flow within the box, which can
result in
fibrous structure imperfections and formation issues.
3. Maximizing heat transfer in and/or out of jets while minimizing mass flow
rates in
quenching streams.
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Accordingly, there is a need for a coforming process and/or a forming box used
in a
coforming process that overcomes the negatives associated with the known
coforming processes
and/or known forming boxes used in coforming processes.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an example of a prior art coforming process that utilizes a forming
box;
Fig. 2 is an example of a prior art coforming process that does not utilize a
forming box;
Fig. 3 is another example of a prior art coforming process that does not
utilize a forming
box;
Fig. 4A is a cross-sectional, schematic view of an example of a forming box in
accordance with the present invention used in a coforming process of the
present invention;
Fig. 4B is a cross-sectional, schematic view of another example of a forming
box in
accordance with the present invention;
Fig. 5 is another example of a forming box in accordance with the present
invention;
Fig. 6A is an example of a fibrous structure making process in accordance with
the
present invention;
Fig. 6B is another example of a fibrous structure making process in accordance
with the
present invention;
Fig. 6C is another example of a fibrous structure making process in accordance
with the
present invention;
Fig. 6D is another example of a fibrous structure making process in accordance
with the
present invention;
Fig. 6E is another example of a fibrous structure making process in accordance
with the
present invention;
Fig. 7 is an example of a die useful in the coforming processes of the present
invention;
Fig. 8 is a partial, expanded view of the die shown in Fig. 7;
Fig. 9A is a diagram of a support rack utilized in the HFS Test Method
described herein;
Fig. 9B is a cross-sectional view of Fig. 9A;
Fig. 10A is a diagram of a support rack cover utilized in the VFS Test Method
described
herein;
Fig. 10B is a cross-sectional view of Fig. 10A; and
Fig. ibis a schematic representation of an apparatus used in the Sled Surface
Drying Test
Method.
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SUMMARY OF THE INVENTION
The present invention fulfills the need described above by providing a
coforming process
and/or a forming box that commingles two or more separate materials at a non-
90 angle, for
example at an angle of less than 90 .
One solution to the problem identified above with respect to known coforming
processes
and known forming boxes is to increase the stability of the coforming process
by utilizing a forming
box within which two or more separate materials, such as filaments and pulp
fibers, are
commingled in a non-perpendicular fashion, for example in a non-90 angle,
such as an angle of
less than 90 and/or less than 85 and/or less than 75 and/or less than 45
and/or less than 30
and/or to about 0 and/or to about 10 and/or to about 25 .
Angling the introduction of two or more separate materials (solid additives,
liquid,
continuous, or atomized) through two or more material inlets together at an
angle of less than 90
mitigates this effect, especially at higher momentum ratios between the
materials (MxV). Another
problem that is corrected by this design is the minimization of separated or
stalled flow within the
forming box (coform box). This results in more even weight distribution and
improved sheet
formation.
The present invention has unexpectedly addressed one or more of the multiple
(and
sometimes contradictory) requirements identified above that must occur in the
forming box
(coform box) in order to meet consumer desires; namely,
1. Maximizing jet stability at all mass ratios of the streams (JAR).
2. Minimizing zones of stalls and/or separated flow within the box, which can
result in
fibrous structure imperfections and formation issues.
3. Maximizing heat transfer in and/or out of jets while minimizing mass
flow rates in
quenching streams.
The coforming processes and/or forming boxes (coform boxes) of the present
invention
have solved these problems as follows. With respect to 1 above, one skilled in
the art would realize
that, if one or both of Si and 02 were 90 in Figs. 4A and 4B, an unstable
and/or metastable system
would result. As a main objective of the coform box is to relieve the operator
of the mass flow
constraint of natural entrainment of the process stream, this is especially
true as mass flow rates of
stream A exceeds the natural ability of the center jet to entrain. In
addition, if there are any
imperfections in the CD flow profile of steam A, the closer that either the
momentum ratio between
stream A and center jet (mass x velocity) and/or that one or both of Si and 02
were equal to 90 ,
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the more likely that imperfection is to carry into the final sheet. One way
this can manifest is
through a light CD stripe in the fibrous structure as it forms on the
collection device 56.
With respect to 2 above, proper design of the coform box according to the
present invention
will allow for the minimization of stalls and/or zones of separated flow,
which are particularly
problematic in particle laden flow. Again referring to Fig. 4B, minimizing Ls
reduces the volume
of upward flow associated with the center section of the coform box. In
addition, minimizing the
ratio of Lc/Ls will reduce the volume of separated flow subsequent to the
introduction of streams
and just prior to deposition of the material contained in the coform box upon
the formaminous
surface. In addition, when viewed in cross section, as in Figs. 4A and 4B, the
walls of the coform
box should be designed in accordance with aerodynamic principles. Radiuses
between different
surfaces should be maximized. In the event that the sidewalls in the chutes
are divergent and
creating a diffuser, it should be designed so that the flow does not separate
from one or both walls.
Additionally, the coform box should be designed such that the length of Lc is
appropriate to the
ratio of mass flow rates and length of dimension Lp, such that a flow
separation does not occur in
the lower box while also not overly constricting the flow exiting the box,
which would cause
needlessly high static pressures in the system and effect other components in
aerodynamic
communication with the coform box.
Finally, with respect to 3 above, coform boxes to date have not been
intentionally designed
to maximize the heat transfer (either into or out of a jet), while at the same
time minimizing the
amount of mass used in that heat transfer and maximizing the stability of the
jet undergoing the
transfer. As shown in Figs. 4A and 4B, the coform box of the present invention
addresses this
dichotomy by increasing heat transfer and jet instability at a constant mass
flow rate and velocity
of stream A as Si and/or 02 goes to 90 , increasing heat transfer and jet
instability at a constant
mass flow rate and angle as the velocity of stream A increases (by decreasing
dimension Lp).
In addition, improved heat removal from the coform box of the present
invention can be
achieved by the introduction of liquid water into the coform box, utilizing
the sensible and latent
heat of a liquid to remove heat extremely rapidly from the jet. In addition to
the expeditious
removal of heat, the addition of the liquid to the coform box could impart
additional functionality
to the substrate either through the addition of a dissolved solid which could
precipitate upon liquid
evaporation, or through the addition of a functional liquid.
In one example of the present invention, a forming box (coform box) comprising
one or
more filament inlets, for example polymer filament inlets, and one or more
solid additive inlets,
wherein at least one of the filament inlets is in fluid communication with a
filament source for
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example a polymer filament source, such as a die, and at least one of the
solid additive inlets is in
fluid communication with an additive source, for example a solid additive
source, such that during
operation of the forming box one or more filaments enter the forming box
through the at least one
filament inlet and one or more solid additives enter the forming box through
the at least one solid
additive inlet such that the one or more filaments and the one or more solid
additives contact each
other at anon-90 angle, for example at an angle of less than 90 , is
provided.
In another example of the present invention, a forming box (coform box)
comprising one
or more filament inlets and one or more additive inlets such that at least one
of the one or more
filament inlets is at an angle of less than 90 to at least one of the
additive inlets, is provided.
In another example of the present invention, a forming box comprising one or
more
filament inlets and one or more solid additive inlets wherein at least one of
the one or more filament
inlets and at least one of the one or more solid additive inlets are
positioned in the forming box at
a non-90 angle, for example at an angle of less than 90 , relative one
another, is provided.
In still another example of the present invention, a forming box comprising
one or more
filament inlets and one or more solid additive inlets wherein at least one of
the one or more filament
inlets and at least one of the one or more solid additive inlets are
positioned in the forming box
such that filaments entering the forming box through at least one of the
filament inlets and solid
additives entering the forming box through at least one of the solid additive
inlets contact each
other inside the forming box at a non-90 angle, for example at an angle of
less than 90 , relative
to one another, is provided.
In even still another example of the present invention, a forming box
comprising one or
more filament inlets and one or more solid additive inlets such that filaments
entering the forming
box through at least one of the filament inlets and solid additives entering
the forming box through
at least one of the solid additive inlets contact each other at a non-90
angle, for example at an
angle of less than 90 , relative to one another, is provided.
In yet another example of the present invention, a forming box comprising one
or more
filament inlets and two or more solid additive inlets such that filaments
entering the forming box
through at least one of the filament inlets and solid additives entering the
forming box through at
least two of the solid additive inlets contact each inside the forming box, is
provided.
In still yet another example of the present invention, a forming box
comprising two or more
filament inlets and two or more solid additive inlets such that filaments
entering the forming box
through at least one of the filament inlets and solid additives entering the
forming box through at
least one of the solid additive inlets contact each other inside the forming
box, is provided.
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In yet another example of the present invention, a coforming process
comprising the steps
of:
a. providing a forming box comprising one or more filament inlets and one or
more solid
additive inlets; and
b. introducing one or more filaments into the forming box through at least one
of the one
or more filament inlets and introducing one or more solid additives into the
forming box through
at least one of the one or more solid additive inlets such that the one or
more filaments contact the
one or more solid additives inside the forming box at a non-90 angle, for
example at an angle of
less than 90 , relative to one another, is provided.
In yet another example of the present invention, a coforming process
comprising the steps
of:
a. providing a forming box comprising one or more filament inlets and one or
more solid
additive inlets wherein at least one of the one or more filament inlets is
positioned in the forming
box at a non-90 angle, for example at an angle of less than 90 , relative to
at least one of the one
or more solid additive inlets; and
b. introducing one or more filaments into the forming box through at least one
of the
filament inlets and introducing one or more solid additives into the forming
box through at least
one of the solid additive inlets such that the one or more filaments contact
the one or more solid
additives inside the forming box at a non-90 angle, for example at an angle
of less than 90 ,
relative to one another, is provided.
In even another example of the present invention, a coforming process
comprising the steps
of:
a. providing a single stream of filaments;
b. providing two or more streams of solid additives, for example fibers;
and
c. commingling the single steam of filaments with the two or more streams of
solid
additives, is provided.
In even another example of the present invention, a coforming process
comprising the steps
of:
a. providing a single stream of filaments;
b. providing two or more streams of solid additives, for example fibers; and
c. commingling the single steam of filaments with the two or more streams
of solid
additives inside a forming box, is provided.
In yet another example of the present invention, a coforming process
comprising the steps
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of:
a. providing two or more streams of filaments;
b. providing two or more streams of solid additives, for example fibers;
and
c. commingling the two or more streams of the filaments with the two or
more
streams of solid additives, is provided.
In yet another example of the present invention, a coforming process
comprising the steps
of:
a. providing two or more streams of filaments;
b. providing two or more streams of solid additives, for example fibers;
and
c. commingling the two or more streams of the filaments with the two or more
streams of solid additives inside a forming box, is provided.
In even still yet another example, a process for making a fibrous structure,
the process
comprising the steps of:
a. providing a die comprising one or more filament-forming holes, wherein one
or more
fluid-releasing holes are associated with one filament-forming hole such that
a fluid exiting the
fluid-releasing hole is parallel or substantially parallel to an exterior
surface of a filament exiting
the filament-forming hole;
b. supplying at least a first polymer to the die;
c. producing a plurality of filaments comprising the first polymer from the
die;
d. combining the filaments with solid additives inside a forming box such that
the filaments
and solid additives contact each other at a non-90 angle, for example at an
angle of less than 90 ,
relative to each other to form a mixture; and
e. collecting the mixture on a collection device to produce a fibrous
structure.
In even still yet another example, a process for making a fibrous structure,
the process
comprising the steps of:
a. providing a die comprising one or more filament-forming holes;
b. supplying at least a first polymer to the die;
c. producing a plurality of filaments comprising the first polymer from the
die;
d. combining the filaments with solid additives inside a forming box such that
the filaments
and solid additives contact each other, for example at a non-90 angle, such
as at an angle of less
than 90 , relative to each other to form a mixture; and
e. collecting the mixture on a collection device to produce a fibrous
structure.
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In one example, the angles associated with the forming box and/or inlets of
the forming
box, for example that impact the angle at which a first material, for example
filaments, is contacted
by a second material, for example a solid additive, is controllable and/or
adjustable, for example
during operation.
Accordingly, the present invention provides coforming processes and forming
boxes useful
therein.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
"Coforming" and/or "coforming process" as used herein means a process by which
two or
more separate materials are commingled. In one example, coforming comprises a
process by which
one or more and/or two or more first materials, for example filaments, such as
polymer filaments,
are commingled with one or more and/or two or more second materials, for
example solid
additives, such as fibers, for example pulp fibers. In coforming processes two
or more separate
materials are commingled together to form a mixture of the two or more
materials. For example,
in a coforming process filaments can be commingled with fibers to form a
mixture of filaments
and fibers that can be collected to form a fibrous structure according to the
present invention.
"JAR" as used herein means the mass ratio of air between one of the side
streams of air and
the center stream of air, or Mp/Mj as shown in the Fig. 4B.
"Momentum" is a vector quantity, defined as mass times the velocity vector.
"Housing" as used herein means an enclosed or partially-enclosed volume formed
by one
or more walls through which one or more materials pass.
"Forming box" as used herein means a portion of a housing's volume within
which
commingling of two or more separate materials occurs. In one example, the
forming box is a
portion of the housing within which one or more and/or two or more first
materials, for example
filaments, such as polymer filaments, are commingled with one or more and/or
two or more second
materials, for example solid additives, such as fibers, for example pulp
fibers. The forming box
comprises two or more inlets for receiving two or more separate materials to
be commingled. In
one example, the forming box further comprises at least one outlet for
evacuating the mixture of
materials from the forming box. In one example, the forming box's at least one
outlet opens to a
collection device, for example a fabric and/or belt, such as a patterned belt,
for receiving the
mixture of materials, for example filaments and fibers, resulting in a fibrous
structure. The receipt
by the collection device of the mixture of materials may be aided by a vacuum
box. The forming
box may be a stand alone, separate, discrete, modular device that can be
inserted into a machine,
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such as a fibrous structure making machine, and/or it may be a fully
integrated component of a
larger machine, such as a fibrous structure making machine so long as at least
one first material
and at least one second material, are capable of entering the forming box and
commingling with
one another according to the present invention.
"First material" as used herein means a material that is separate from at
least one other
material, for example a second material. In one example, the first material
comprises filaments,
such as polymer filaments.
"Second material" as used herein means a material that is separate from the
first material.
In one example, the second material comprises solid additives, such as fibers,
for example pulp
fibers.
"Stream(s) of solid additives" as used herein means a plurality of solid
additives, for
example a plurality of fibers, that are moving generally in the same
direction. In one example, a
stream of solid additives is a plurality of solid additives that enter a
forming box of the present
invention through the same solid additive inlet at the same time or
substantially the same time.
"Stream(s) of filaments" as used herein means a plurality of filaments that
are moving
generally in the same direction. In one example, a stream of filaments is a
plurality of filaments
that enter a forming box of the present invention through the same filament
inlet at the same time
or substantially the same time. In one example, the stream of filaments may be
a stream of
meltblown filaments and/or a stream of spunbond filaments.
"Stream(s) of fibers" as used herein means a plurality of fibers that are
moving generally
in the same direction. In one example, a stream of fibers is a plurality of
fibers that enter a forming
box of the present invention through the same fiber inlet at the same time or
substantially the same
time. In one example, the stream of fibers may be a stream of pulp fibers.
"Filament inlet" as used herein means an entrance to the forming box through
which one
or more filaments enter.
"Solid additive inlet" as used herein means an entrance to the forming box
through which
one or more solid additives enter. A "fiber inlet" is an example of a solid
additive inlet wherein
the fiber inlet means an entrance to the forming box through which one or more
fibers enter.
"Fibrous structure" as used herein means a structure that comprises one or
more filaments
and/or one or more fibers, which are considered solid additives for the
present invention. In one
example, a fibrous structure according to the present invention means an
orderly arrangement of
filaments and solid additives within a structure in order to perform a
function. Non-limiting
examples of fibrous structures of the present invention include paper, fabrics
(including woven,
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knitted, and non-woven), and absorbent pads (for example for diapers or
feminine hygiene
products).
In one example, the fibrous structure is wound on a roll, for example in a
plurality of
perforated sheets, and/or cut into discrete sheets.
The fibrous structures of the present invention may be homogeneous or may be
layered. If
layered, the fibrous structures may comprise at least two and/or at least
three and/or at least four
and/or at least five layers.
The fibrous structures of the present invention are co-formed fibrous
structures.
"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.
"Solid additive" as used herein means a fiber and/or a particulate.
"Particulate" as used herein means a granular substance, powder and/or
particle, such as an
absorbent gel material particle.
"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. For
purposes of the present invention, 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.).
Fibers are typically considered discontinuous in nature. Non-limiting examples
of fibers
include wood pulp fibers and synthetic staple fibers such as polyester fibers.
Filaments are typically considered continuous or substantially continuous in
nature.
Filaments are relatively longer than fibers. Non-limiting examples of
filaments include meltblown
and/or spunbond filaments. Non-limiting examples of materials that can be spun
into filaments
include natural polymers, such as starch, starch derivatives, cellulose and
cellulose derivatives,
hemicellulose, hemicellulose 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
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may be monocomponent or multicomponent, such as bicomponent filaments. In one
example, the
polymer filaments of the present invention comprise a thermoplastic polymer,
for example a
thermoplastic polymer selected from the group consisting of: polyeolefins,
such as polypropylene
and/or polyethylene, polyesters, polyvinyl alcohol, nylons, polylactic acid,
polyhydroxyalkanoate,
polycaprolactone, and mixtures thereof In one example, the thermoplastic
polymer comprises a
polyolefin, for example polypropylene and/or polyethylene. In another example,
the thermoplastic
polymer comprises polypropylene.
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, groundwood, 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 web. U.S.
Pat. No. 4,300,981 and
U.S. Pat. No. 3,994,771 disclose layering of hardwood and softwood fibers.
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.
In addition to the various wood pulp fibers, other cellulosic fibers such as
cotton linters,
rayon, lyocell and bagasse can be used in this invention. Other sources of
cellulose in the form of
fibers or capable of being spun into fibers include grasses and grain sources.
"Sanitary tissue product" as used herein means a soft, low density (i.e. <
about 0.15 g/cm3)
web useful as a wiping implement for post-urinary and post-bowel movement
cleaning (toilet
tissue), for otorhinolaryngological discharges (facial tissue), and multi-
functional absorbent and
cleaning uses (absorbent towels). The sanitary tissue product may be
convolutedly wound upon
itself about a core or without a core to form a sanitary tissue product roll.
In one example, the sanitary tissue product of the present invention comprises
a fibrous
structure according to the present invention.
The sanitary tissue products of the present invention may exhibit a basis
weight between
about 10 g/m2 to about 120 g/m2 and/or from about 15 g/m2 to about 110 g/m2
and/or from about
20 g/m2 to about 100 g/m2 and/or from about 30 to 90 g/m2. In addition, the
sanitary tissue product
Date recue / Date received 2021-12-03
13
of the present invention may exhibit a basis weight between about 40 g/m2 to
about 120 g/m2 and/or
from about 50 g/m2 to about 110 g/m2 and/or from about 55 g/m2 to about 105
g/m2 and/or from
about 60 to 100 g/m2.
The sanitary tissue products of the present invention may exhibit a total dry
tensile strength
of greater than about 59 g/cm (150 g/M) and/or from about 78 g/cm (200 g/in)
to about 394 g/cm
(1000 g/in) and/or from about 98 g/cm (250 Win) to about 335 g/cm (850 Win).
In addition, the
sanitary tissue product of the present invention may exhibit a total dry
tensile strength of greater
than about 196 g/cm (500 g/in) and/or from about 196 g/cm (500 g/in) to about
394 g/cm (1000
g/in) and/or from about 216 g/cm (550 g/in) to about 335 g/cm (850 g/in)
and/or from about 236
g/cm (600 g/in) to about 315 g/cm (800 g/in). In one example, the sanitary
tissue product exhibits
a total dry tensile strength of less than about 394 g/cm (1000 g/in) and/or
less than about 335 g/cm
(850 g/in).
In another example, the sanitary tissue products of the present invention may
exhibit a total
dry tensile strength of greater than about 196 g/cm (500 g/in) and/or greater
than about 236 g/cm
(600 Win) and/or greater than about 276 g/cm (700 Win) and/or greater than
about 315 g/cm (800
g/in) and/or greater than about 354 g/cm (900 g/in) and/or greater than about
394 g/cm (1000 Win)
and/or from about 315 g/cm (800 g/in) to about 1968 g/cm (5000 g/in) and/or
from about 354 g/cm
(900 g/in) to about 1181 g/cm (3000 g/in) and/or from about 354 g/cm (900
g/in) to about 984 g/cm
(2500 g/in) and/or from about 394 g/cm (1000 g/in) to about 787 g/cm (2000
g/in).
The sanitary tissue products of the present invention may exhibit an initial
total wet tensile
strength of less than about 78 g/cm (200 g/in) and/or less than about 59 g/cm
(150 g/in) and/or less
than about 39 g/cm (100 Win) and/or less than about 29 g/cm (75 g/in).
The sanitary tissue products of the present invention may exhibit an initial
total wet tensile
strength of greater than about 118 g/cm (300 g/in) and/or greater than about
157 g/cm (400 Win)
and/or greater than about 196 g/cm (500 g/in) and/or greater than about 236
g/cm (600 g/in) and/or
greater than about 276 g/cm (700 g/in) and/or greater than about 315 g/cm (800
g/in) and/or greater
than about 354 g/cm (900 g/in) and/or greater than about 394 g/cm (1000 g/in)
and/or from about
118 g/cm (300 g/in) to about 1968 g/cm (5000 g/in) and/or from about 157 g/cm
(400 g/in) to about
1181 g/cm (3000 g/in) and/or from about 196 g/cm (500 g/in) to about 984 g/cm
(2500 g/in) and/or
from about 196 g/cm (500 g/in) to about 787 g/cm (2000 g/in) and/or from about
196 g/cm (500
g/in) to about 591 g/cm (1500 g/in).
The sanitary tissue products of the present invention may exhibit a density
(measured at 95
g/in2) of less than about 0.60 g/cm3 and/or less than about 0.30 g/cm3 and/or
less than about 0.20
Date recue / Date received 2021-12-03
14
g/cm3 and/or less than about 0.10 g/cm3 and/or less than about 0.07 g/cm3
and/or less than about
0.05 g/cm3 and/or from about 0.01 g/cm3 to about 020 g/cm3 and/or from about
0.02 g/cm3 to
about 0.10 g/cm3.
The sanitary tissue products of the present invention may exhibit a total
absorptive capacity
of according to the Horizontal Full Sheet (HFS) Test Method described herein
of greater than about
g/g and/or greater than about 12 g/g and/or greater than about 15 g/g and/or
from about 15 g/g
to about 50 g/g and/or to about 40 g/g and/or to about 30 g/g.
The sanitary tissue products of the present invention may exhibit a Vertical
Full Sheet
(VFS) value as determined by the Vertical Full Sheet (VFS) Test Method
described herein of
10 greater than about 5 g/g and/or greater than about 7 g/g and/or greater
than about 9 g/g and/or from
about 9 g/g to about 30 g/g and/or to about 25 g/g and/or to about 20 g/g
and/or to about 17 g/g.
The sanitary tissue products of the present invention may be in the form of
sanitary tissue
product rolls. Such sanitary tissue product rolls may comprise a plurality of
connected, but
perforated sheets of fibrous structure, that are separably dispensable from
adjacent sheets. In one
example, one or more ends of the roll of sanitary tissue product may comprise
an adhesive and/or
dry strength agent to mitigate the loss of fibers, especially wood pulp fibers
from the ends of the
roll of sanitary tissue product.
The sanitary tissue products of the present invention may comprise additives
such as
softening agents, temporary wet strength agents, permanent wet strength
agents, bulk softening
agents, lotions, silicones, wetting agents, latexes, especially surface-
pattern-applied latexes, dry
strength agents such as carboxymethylcellulose and starch, and other types of
additives suitable
for inclusion in and/or on sanitary tissue products.
"Basis Weight" as used herein is the weight per unit area of a sample reported
in lbs/3000
ft2 or g/m2.
"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.
"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.
"Ply" as used herein means an individual, integral fibrous structure.
"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
Date recue / Date received 2021-12-03
15
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
"Total Pore Volume" as used herein means the sum of the fluid holding void
volume in
.. each pore range from liam to 10001.1m radii as measured according to the
Pore Volume Test Method
described herein.
"Pore Volume Distribution" as used herein means the distribution of fluid
holding void
volume as a function of pore radius. The Pore Volume Distribution of a fibrous
structure is
measured according to the Pore Volume Test Method described herein.
"Additives" as used herein means the additives solid additives, liquid
additives, gas
additives, plasma additives, and mixtures thereof Even though the examples
exemplified herein
are directed to solid additives, other additives may be utilized with the
forming boxes of the present
invention. In one example, the additive is a solid additive, such as pulp, for
example wood pulp
fibers. In another example, the additive may comprise a liquid additive, for
example a liquid
additive comprising a dissolved solid additive that precipitates in the
forming box during operation.
As used herein, the articles "a" and "an" when used herein, for example, "an
anionic
surfactant" or "a fiber" is understood to mean one or more of the material
that is claimed or
described.
All percentages and ratios are calculated by weight unless otherwise
indicated. All
percentages and ratios are calculated based on the total composition unless
otherwise indicated.
Unless otherwise noted, all component or composition levels are in reference
to the active
level of that component or composition, and are exclusive of impurities, for
example, residual
solvents or by-products, which may be present in commercially available
sources.
Forming Box
Figs. 4A and 4B show examples of forming boxes 30 of the present invention.
The forming
boxes 30 are defined by a housing 32. The housing 32 may be made from any
suitable material
such as metal, polycarbonate, or glass. The housing 32 encloses and/or defines
the forming boxes'
volume 34 where at least a first material, for example one or more filaments
36, for example
polymer filaments such as polyolefin filaments (e.g., polypropylene
filaments), which enters the
forming box 30 through one or more first material inlets, for example filament
inlets 38, and at
least a second material, for example one or more solid additives 40, such as
fibers, for example
Date recue / Date received 2021-12-03
16
pulp fibers (e.g., wood pulp fibers), which enters the forming box 30 through
one or more second
material inlets, for example solid additive inlets 42, commingle.
In one example as shown in Fig. 4A, the first material, for example filaments
36,
commingle with the second material, for example fibers 40, inside the forming
box's volume 34
defined by the housing 32 as a result of the second material, for example
fibers 40, contacting the
first material, for example filaments 34, at an angle 01 and/or 02, at least
one of which is not 90 (a
non-90 angle), for example at an angle of less than 90 and/or less than 85
and/or less than 75
and/or less than 45 and/or less than 30 and/or to about 0 and/or to about
10 and/or to about 25 .
In one example, at least one of the first material inlets, for example
filament inlets 38, is
positioned within the housing 32 at anon-90 angle, for example at an angle of
less than 90 and/or
less than 85 and/or less than 75 and/or less than 45 and/or less than 30
and/or to about 0 and/or
to about 10 and/or to about 25 with respect to at least one of the second
material inlets, for
example solid additive inlets 42. This non-90 angle can be achieved by
various ways, for example
by fixed designs of the first material inlets and/or second material inlets
and/or by controllable
and/or adjustable designs of the first material inlets and/or second material
inlets.
In another example, one or more first material inlets, for example filament
inlets 38, may
be in fluid communication with a first material source, such as a filament
source for example a
polymer filament source comprising a spinnerette, such as a die 44, that
supplies filaments 36 to at
least one of the filament inlets 38.
In another example, one or more second material inlets, for example solid
additive inlets
42 is in fluid communication with an additive source, for example a solid
additive source, such as
a fiber source 46, such as a fiber spreader and/or a hammermill and/or a
forming head and/or
eductor, that supplies fibers 40 to at least one of the solid additive inlets
42.
As shown in Fig. 4B, an example of a forming box, for example coform box,
according to
the present invention may exhibit the following dimensions and/or ratios of
the dimensions. In one
example, dimension Lj may be greater than 0.03 and/or greater than 0.05 and/or
greater than 0.075
and/or greater than 0.1 and/or greater than 0.125 and/or less than 10 and/or
less than 7 and/or less
than 5 and/or less than 3 inches. In another example, dimension Lj is from
about 0.125 to about 3
inches. In one example, dimension Lp may be greater than 0.1 and/or greater
than 0.25 and/or
greater than 0.5 and/or greater than 0.75 and/or greater than 1 and/or less
than 15 and/or less than
12 and/or less than 10 and/or less than 8 and/or less than 6 inches. In
another example, dimension
Lp is from about 1 to about 6 inches. In one example, dimension Lc may be
greater than 0.5 and/or
greater than 0.75 and/or greater than 1 and/or greater than 1.25 and/or
greater than 1.5 and/or
Date recue / Date received 2021-12-03
17
greater than 2 and/or less than 30 and/or less than 25 and/or less than 20
and/or less than 15 and/or
less than 12 inches. In another example, dimension Lc is from about 2 to about
12 inches. In one
example, dimension Ls may be greater than 0.1 and/or greater than 0.25 and/or
greater than 0.5
and/or greater than 0.75 and/or greater than 1 and/or less than 30 and/or less
than 25 and/or less
than 20 and/or less than 15 and/or less than 12 inches. In another example,
dimension Ls is from
about 1 to about 12 inches. In one example, the forming box of the present
invention exhibits
dimension ratios of Lc:Ls of less than 12:1 and/or less than 12:7 and/or less
than 7:7 and/or less
than 3:7. In another example, the forming box of the present invention
exhibits dimension ratios
of Lc:Lp of less than 12:1 and/or less than 11:4 and/or less than 7:4 and/or
less than 3:4.
In one example, a coforming process that utilizes a forming box of the present
invention,
for example as shown in Figs. 4A or 4B, exhibits a JAR during operation of at
least 0.5 and/or at
least 1 and/or at least 1.5 and/or at least 2 and/or at least 2.5 and/or at
least 3.0 and/or at least 3.5
and/or at least 4.0 and/or less than 15 and/or less than 12 and/or less than
10 and/or less than 8.
In another example, a fibrous structure made from a coforming process of the
present
invention, for example that uses a forming box in accordance with the present
invention, for
example as shown in Figs. 4A or 4B, exhibits a MD Basis Weight Coefficient of
Variation (COV)
of less than 11% and/or less than 10% and/or less than 8% and/or less than 6%
and/or about 0%
and/or greater than 0.5% as measured according to the MD Basis Weight Test
Method described
herein.
In yet another example, a fibrous structure made from a coforming process of
the present
invention, for example that uses a forming box in accordance with the present
invention, for
example as shown in Figs. 4A or 4B, wherein the coforming process exhibits a
JAR during
operation of at least 0.5 and/or at least 1 and/or at least 1.5 and/or at
least 2 and/or at least 2.5
and/or at least 3.0 and/or at least 3.5 and/or at least 4.0 and/or less than
15 and/or less than 12
and/or less than 10 and/or less than 8 exhibits a MD Basis Weight Coefficient
of Variation (COV)
of less than 11% and/or less than 10% and/or less than 8% and/or less than 6%
and/or about 0%
and/or greater than 0.5% as measured according to the MD Basis Weight Test
Method described
herein.
MD Basis Weight COV data for fibrous structures (Inventive A-D) of the present
invention
made according to the present invention and/or using the coforming processes
of the present
invention and the forming boxes of the present invention are shown in Table 1
below along with
examples of known fibrous structures (1-4) that were made without using the
processes and/or
forming boxes of the present invention.
Date recue / Date received 2021-12-03
18
MD Basis
Sample Weight
COV
1 13.1%
2 11.6%
3 12.8%
4 13.5%
Inventive A 6.8%
Inventive B 7.6%
Inventive C 5.1%
Inventive D 4.7%
In one example of the present invention, a forming box comprises one or more
filament
inlets and one or more solid additive inlets, wherein at least one of the
filament inlets is in fluid
communication with a filament source and at least one of the solid additive
inlets is in fluid
communication with an additive source, for example a solid additive source,
such that during
operation of the forming box one or more filaments enter the forming box
through the at least one
filament inlet and one or more solid additives enter the forming box through
the at least one solid
additive inlet such that the one or more filaments and the one or more solid
additives contact each
other at anon-90 angle, for example at an angle of less than 90 .
In another example of the present invention, a forming box comprises one or
more filament
inlets and one or more solid additive inlets wherein at least one of the one
or more filament inlets
and at least one of the one or more solid additive inlets are positioned in
the housing at a non-90
angle, for example at an angle of less than 90 and/or less than 85 and/or
less than 75 and/or less
than 45 and/or less than 30 and/or to about 0 and/or to about 10 and/or to
about 25 relative to
one another. This non-90 angle can be achieved by various ways, for example
by fixed orientation
of the filament inlets and/or solid additive inlets within the housing and/or
by controllable and/or
adjustable orientations of the filament inlets and/or solid additive inlets
within the housing.
In still another example of the present invention, a forming box comprises one
or more
filament inlets and one or more solid additive inlets wherein at least one of
the one or more filament
inlets and at least one of the one or more solid additive inlets are
positioned in the housing such
that filaments entering the forming box through at least one of the filament
inlets and solid additives
entering the forming box through at least one of the solid additive inlets
contact each other inside
the forming box at anon-90 angle, for example at an angle of less than 90 ,
relative to one another.
Date recue / Date received 2021-12-03
19
In even still another example of the present invention, a forming box
comprises one or more
filament inlets and one or more solid additive inlets such that filaments
entering the forming box
through at least one of the filament inlets and solid additives entering the
forming box through at
least one of the solid additive inlets contact each other at a non-90 angle,
for example at an angle
of less than 90 , relative to one another.
In yet another example of the present invention, a forming box comprises one
or more
filament inlets and two or more solid additive inlets such that filaments
entering the forming box
through at least one of the filament inlets and solid additives entering the
forming box through at
least two of the solid additive inlets contact each inside the forming box.
In still yet another example of the present invention, a forming box comprises
two or more
filament inlets and two or more solid additive inlets such that filaments
entering the forming box
through at least one of the filament inlets and solid additives entering the
forming box through at
least one of the solid additive inlets contact each other inside the forming
box.
In one example, the housing is designed to inhibit and/or prevent and/or
mitigate buildup
and/or deposition of materials, such as filaments and/or solid additive on the
walls of the housing.
In one example, the housing is subjected to heat prior to, during, and/or
after the coforming process.
In another example, the forming box may comprise, in addition to the first
material inlets
and the second material inlets, a plurality of other material inlets, such as
an inlet for steam and/or
moisture. The orientation of these other material inlets may be the same or
different as described
above with respect to the first and second material inlets, for example
regarding angles relating to
the positioning of the other material inlets within the housing defining the
volume of the forming
box.
In one example, the forming box (coform box) of the present invention is
geometrically
symmetric with respect to the forming box's cross machine-direction axis. In
another example,
the forming box (coform box) of the present invention exhibits symmetric
momentum with respect
to the forming box's cross machine-direction axis. In still another example,
the forming box
(coform box) of the present invention exhibits symmetric horizontal momentum
with respect to the
forming box's cross machine-direction axis.
In one example, the inlets, for example at least two of the additive inlets,
are independently
controllable during operation, for example independently controllable with
respect to
concentration, type of additive, composition, aspect ratio of additive, and
mixtures thereof
Date recue / Date received 2021-12-03
20
In another example, the filament inlets, for example at least two of the
polymer filament
inlets are independently controllable during operation, for example
independently controllable with
respect to concentration, type of polymer, composition, and mixtures thereof
.. Coforming Process
A non-limiting example of a coforming process is also shown in Figs. 4A and
4B. In one
example, as shown in Figs. 4A and 4B, a coforming process comprises the steps
of:
a. providing a forming box 30 defined by a housing 32, wherein the forming
box 30
comprises one or more first discrete material inlets, for example one or more
filament inlets 38
and one or more second material inlets, for example one or more solid additive
inlets 42; and
b. introducing one or more filaments 36 into the forming box 30 through at
least one of
the one or more first material inlets, for example one or more filament inlets
38, and introducing
one or more solid additives 40, such as fibers, into the forming box 30
through at least one of the
one or more second material inlets, for example one or more solid additive
inlets 42, such that the
one or more filaments 36 contact the one or more solid additives 40, for
example fibers, inside
the volume 34 defined by the housing 32 at a non-90 angle, for example at an
angle of less than
90 and/or less than 85 and/or less than 75 and/or less than 45 and/or less
than 30 and/or to
about 0 and/or to about 10 and/or to about 25 , relative to one another, is
provided.
Another example of a coforming process according to the present invention is
also shown
.. in Figs. 4A and 4B. This coforming process comprises the steps of:
a. providing a forming box 30 defined by a housing 32, wherein the forming
box 30
comprises one or more first discrete material inlets, for example one or more
filament inlets 38
and one or more second material inlets, for example one or more solid additive
inlets 42, wherein
at least one of the one or more filament inlets 38 is positioned in the
housing 32 at a non-90
.. angle, for example at an angle of less than 90 and/or less than 85 and/or
less than 75 and/or
less than 45 and/or less than 30 and/or to about 0 and/or to about 10
and/or to about 25 ,
relative to at least one of the one or more solid additive inlets; and
b. introducing one or more filaments 36 into the forming box 30 through at
least one of
the filament inlets 38 and introducing one or more solid additives 40 into the
forming box 30
through at least one of the solid additive inlets 42 such that the one or more
filaments 36 contact
the one or more solid additives 40 inside the volume 34 defined by the housing
32 at a non-90
angle, for example at an angle of less than 90 and/or less than 85 and/or
less than 75 and/or
Date recue / Date received 2021-12-03
21
less than 45 and/or less than 30 and/or to about 0 and/or to about 10
and/or to about 25 ,
relative to one another.
In even another example as shown in Figs. 4A and 4B, a coforming process
comprising
the steps of:
a. providing a single stream of filaments 36;
b. providing two or more streams of solid additives 40, for example fibers;
and
c. commingling the single steam of filaments 36 with the two or more
streams of solid
additives 40. This coforming process example may or may not include the use of
a forming box
30. In one example, the coforming process does include the use of a forming
box 30 wherein the
single stream of filaments 36 and the two or more streams of solid additives
40, such as a fibers,
commingle by the two or more streams of solid additives 40 contacting the
single stream of
filaments 36 inside the volume 34 defined by the housing 32 at a non-90
angle, for example at
an angle of less than 90 and/or less than 85 and/or less than 75 and/or
less than 45 and/or less
than 30 and/or to about 00 and/or to about 10 and/or to about 25 , relative
to one another.
In even another example of the present invention as shown in Fig. 5, a
coforming process
comprising the steps of:
a. providing two or more streams of filaments 36;
b. providing two or more streams of solid additives 40, for example fibers;
and
c. commingling the two or more streams of the filaments 36 with the two or
more
streams of solid additives 40, is provided. This coforming process example may
or may not
include the use of a forming box 30. In one example, the coforming process
does include the use
of a forming box 30 wherein the two or more streams of filaments 36 and the
two or more
streams of solid additives 40, such as a fibers, commingle by the two or more
streams of solid
additives 40 contacting the two or more streams of filaments 36 inside the
volume 34 defined by
the housing 32 at a non-90 angle (angled 03, 04, 05, and 06) for example at
an angle of less than
90 and/or less than 85 and/or less than 75 and/or less than 45 and/or less
than 30 and/or to
about 0 and/or to about 10 and/or to about 25 , relative to one another.
Process For Making A Fibrous Structure
As shown in Figs. 4A and 4B, a non-limiting example of a process for making a
fibrous
structure according to the present invention comprises the steps of:
a. providing a filament source 44 comprising a die 48 (as shown in Figs. 7 and
8), for
example a multi-row capillary die, comprising one or more filament-forming
holes 50, wherein
Date recue / Date received 2021-12-03
22
one or more fluid-releasing holes 52 are associated with one filament-forming
hole 50 such that a
fluid, such as air, exiting the fluid-releasing hole 52 is parallel or
substantially parallel (less than
45 and/or less than 30 and/or less than 20 and/or less than 15 and/or less
than 10 and/or less
than 5 and/or less than 3 and/or about 0 to an exterior surface of a
filament exiting the filament-
forming hole 50;
b. supplying at least a first polymer to the die 48;
c. producing a plurality of filaments 36 comprising the first polymer from the
die 48;
d. combining the filaments 36 with solid additives 40 delivered from a solid
additive source
46, such as a hammermill and/or solid additive spreader and/or airlaying
equipment such as a
forming head, for example a forming head from Dan-Web Machinery A/S, and/or an
eductor,
inside a forming box 30 defined by a housing 32 that defines a forming box's
volume 34 such that
the filaments 36 and solid additives 40 contact each other at a non-90 angle,
for example at an
angle of less than 90 and/or less than 85 and/or less than 75 and/or less
than 45 and/or less than
30 and/or to about 0 and/or to about 10 and/or to about 25 , relative to
each other to form a
mixture; and
e. collecting the mixture 54 on a collection device 56, such as a fabric
and/or belt, for
example a patterned belt that imparts a pattern, for example a non-random,
repeating pattern to a
fibrous structure, with or without the aid of a vacuum box 58, to produce a
fibrous structure 60.
The forming box 30 may comprise one or more first material inlets, for example
one or
more filament inlets 38 through which one or more filaments 36, for example
meltblown
filaments, are introduced into the forming box 30, and one or more second
material inlets, for
example one or more solid additive inlets 42 through which one or more solid
additives 40, such
as fibers, are introduced into the forming box 30 such that one or more
filaments 36 contact the
one or more solid additives 40, for example fibers, inside the volume 34 of
the forming box 30.
In another example of the present invention as shown in Figs. 6A to 6E, a
fibrous
structure making process comprises the steps of:
a. providing a filament source 44, for example a die, such as a spunbond die
or a meltblow
die 48 as shown in Figs. 7 and 8, which illustrates an example of a multi-row
capillary die
comprising one or more filament-forming holes 50, wherein one or more fluid-
releasing holes 52
are associated with one filament-forming hole 50 such that a fluid, such as
air, exiting the fluid-
releasing hole 52 is parallel or substantially parallel (less than 45 and/or
less than 30 and/or less
than 20 and/or less than 15 and/or less than 10 and/or less than 5 and/or
less than 3 and/or
about 0 to an exterior surface of a filament exiting the filament-forming
hole 50;
Date recue / Date received 2021-12-03
23
b. supplying at least a first polymer to the filament source 44;
c. producing a plurality of filaments 36 comprising the first polymer from the
filament
source 44;
d. combining the filaments 36 with solid additives 40 delivered from a solid
additive source
(not shown), such as a hammermill and/or solid additive spreader and/or
airlaying equipment such
as a forming head, for example a forming head from Dan-Web Machinery A/S,
and/or an eductor,
inside a forming box 30 defined by a housing 32 that defines a forming box's
volume 34 such that
the filaments 36 and solid additives 40 contact each other at a 90 angle
and/or at a non-90 angle,
for example at an angle of less than 90 and/or less than 85 and/or less than
75 and/or less than
45 and/or less than 30 and/or to about 0 and/or to about 10 and/or to
about 25 , relative to each
other to form a mixture; and
e. collecting the mixture 54 on a collection device 56, such as a fabric
and/or belt, for
example a patterned belt that imparts a pattern, for example a non-random,
repeating pattern to a
fibrous structure, with or without the aid of a vacuum box 58, to produce a
fibrous structure 60.
The fibrous structure making process as shown in Figs. 6A to 6E may further
comprise one
or more air sources 62, such as cooling air, quenching air, and/or drying air.
In one example, as
shown in Fig. 6E the components of the fibrous structure making process, for
example the one or
more filament sources 44, the one or more air sources 62, the forming box 30
along with its inlets
38 and 42 may all be connected to one another by housing 32.
In another example, as shown in Figs. 6A to 6E, the fibrous structure making
process may
further comprise a venturi attenuation zone 64. In one example, the venturi
attenuation zone 64
comprises one or more high velocity air sources 66 that delivers high velocity
air to the filaments
36 prior to the forming box 30 (as shown in Fig. 6B) and/or to the mixture 54
of filaments 36 and
solid additives 40 after the forming box 30 (as shown in Figs. 6A, 6C, 6D, and
6E).
In one example, during operation, as shown in Fig. 6B, the filament source 44
receives
molten polymer, for example a polyolefin, such as polypropylene, under
pressure. This molten
polymer is then spun via pressure from the filament source 44 (for example a
die) to form filaments
36. The filaments 36 are subjected to cooling air, from one or more air
sources 62, which serves
to lower the molten polymer to below its freezing temperature. The filaments
36 continue traveling
toward the collection device 56 and are aided in attenuation by the venturi
attenuation zone 64.
Subsequent to the venturi attenuation zone 64, one or more solid additives 40
¨ laden flow is then
introduced into the filaments 36 in the forming box 30. The filaments 36 are
aided in attenuation
by the venturi attenuation zone 64. The mixture 54 is then collected on the
collection device 56,
Date recue / Date received 2021-12-03
24
with or without the aid of the vacuum box 58, to form the fibrous structure
60. The fibrous structure
60 may then be subjected to further post processing operations such as thermal
bonding,
embossing, tuft-generating operations, slitting, cutting, perforating, and
other converting
operations.
In another example, during operation, as shown in Figs. 6A, 6C, 6D, and 6E,
the filament
source 44 receives molten polymer, for example a polyolefin, such as
polypropylene, under
pressure. This molten polymer is then spun via pressure from the filament
source 44 (for example
a die) to form filaments 36. The filaments 36 are subjected to cooling air,
from one or more air
sources 62, which serves to lower the molten polymer to below its freezing
temperature. The
filaments 36 continue traveling toward the collection device 56. One or more
solid additives 40 ¨
laden flow is then introduced into the filaments 36 in the forming box 30. The
filaments 36 are
aided in attenuation by the venturi attenuation zone 64. The mixture 54 is
then collected on the
collection device 56, with or without the aid of the vacuum box 58, to form
the fibrous structure
60. The fibrous structure 60 may then be subjected to further post processing
operations such as
thermal bonding, embossing, tuft-generating operations, slitting, cutting,
perforating, and other
converting operations.
In one example, the forming box 30 (coform box), as shown in Fig. 6E,
comprises one or
more filament inlets 38, one or more cooling air inlets 63 through which
cooling air enters the
housing 32 from one or more air sources 62, one or more solid additive inlets
42, and one or more
venturi attenuation zones 64, which aid in attenuation filaments 36 passing
through the forming
box 30 and/or the housing 32 defining the forming box 30.
The forming box 30 may comprise one or more first material inlets, for example
one or
more filament inlets 38 through which one or more filaments 36, for example
spunbond filaments,
are introduced into the forming box 30, and one or more second material
inlets, for example one
or more solid additive inlets 42 through which one or more solid additives 40,
such as fibers, are
introduced into the forming box 30 such that one or more filaments 36 contact
the one or more
solid additives 40, for example fibers, inside the volume 34 of the forming
box 30.
In another example as shown in Figs. 4A and 4B, a fibrous structure making
process of the
present invention comprises the step of commingling a plurality of solid
additives 40 with a
plurality of filaments 36. In one example, the solid additives 40 are wood
pulp fibers, such as SSK
fibers and/or Eucalytpus fibers, and the filaments 36 are polypropylene
filaments. The solid
additives 40 may be combined with the filaments 36, such as by being delivered
to a stream of
filaments 36 from a solid additive source 46 such as a hammermill via a solid
additive spreader
Date recue / Date received 2021-12-03
25
and/or forming head and/or eductor to form a mixture 54 of filaments 36 and
solid additives 40.
In one example, an apparatus for separating the solid additives 40 as
described in US Patent
Application Publication No. 20110303373 may be used to facilitate delivery of
the solid additives
40. In one example, the solid additives 40 may be delivered to the stream of
filaments 36 from
two or more sides of the stream of filaments 36. The filaments 36 may be
created by meltblowing
from a meltblow die, for example a die 48 of Figs. 7 and 8. The mixture 54 of
solid additives 40
and filaments 36 are collected on a collection device 56, such as a belt to
form a fibrous structure
60. The collection device 54 may be a patterned and/or molded belt that
results in the fibrous
structure 60 exhibiting a surface pattern, such as a non-random, repeating
pattern of microregions.
The molded belt may have a three-dimensional pattern on it that gets imparted
to the fibrous
structure 60 during the process. For example, the patterned belt may comprise
a reinforcing
structure, such as a fabric upon which a polymer resin is applied in a
pattern. The pattern may
comprise a continuous or semi-continuous network of the polymer resin within
which one or more
discrete conduits are arranged.
In one example of the present invention, the fibrous structure 60 is made
using a die 48
(Figs. 7 and 8) comprising at least one and/or 2 or more and/or 3 or more rows
of filament-forming
holes 50 from which filaments 36 are spun. At least one row contains 2 or more
and/or 3 or more
and/or 10 or more filament-forming holes 50. In addition to the filament-
forming holes 50, the die
48 comprises fluid-releasing holes 52, such as gas-releasing holes, in one
example air-releasing
holes, that provide attenuation to the filaments 36 formed from the filament-
forming holes 50. One
or more fluid-releasing holes 52 may be associated with a filament-forming
hole 50 such that the
fluid exiting the fluid-releasing hole 52 is parallel or substantially
parallel (rather than angled like
a knife-edge die) to an exterior surface of a filament 36 exiting the filament-
forming hole 50. In
one example, the fluid exiting the fluid-releasing hole 52 contacts the
exterior surface of a filament
36 formed from a filament-forming hole 50 at an angle of less than 30 and/or
less than 20 and/or
less than 10 and/or less than 5 and/or about 0 . One or more fluid releasing
holes 52 may be
arranged around a filament-forming hole 50. In one example, one or more fluid-
releasing holes 52
are associated with a single filament-forming hole 50 such that the fluid
exiting the one or more
fluid releasing holes 52 contacts the exterior surface of a single filament 36
formed from the single
filament-forming hole 50. In one example, the fluid-releasing hole 52 permits
a fluid, such as a
gas, for example air, to contact the exterior surface of a filament 36 formed
from a filament-forming
hole 50 rather than contacting an inner surface of a filament 36, such as what
happens when a
hollow filament is formed.
Date recue / Date received 2021-12-03
26
In one example, the die 48 comprises a filament-forming hole 50 positioned
within a fluid-
releasing hole 52. The fluid-releasing hole 52 may be concentrically or
substantially concentrically
positioned around a filament-forming hole 50 such as is shown in Figs. 7 and
8.
After the fibrous structure 60 has been formed on the collection device 56,
the fibrous
structure 60 may be subjected to post-processing operations such as embossing,
thermal bonding,
tuft-generating operations, moisture-imparting operations, slitting, folding,
lotioning, surface
treating, and combining with other fibrous structure plies operations (not
shown) to form a finished
fibrous structure or sanitary tissue product. One example of a surface
treating operation that the
fibrous structure may be subjected to is the surface application of an
elastomeric binder, such as
ethylene vinyl acetate (EVA), latexes, and other elastomeric binders. Such an
elastomeric binder
may aid in reducing the lint created from the fibrous structure during use by
consumers. The
elastomeric binder may be applied to one or more surfaces of the fibrous
structure in a pattern,
especially a non-random repeating pattern, or in a manner that covers or
substantially covers the
entire surface(s) of the fibrous structure.
After the fibrous structure 60 has been formed on the collection device 56,
such as a
patterned belt, the fibrous structure 60 may be calendered, for example, while
the fibrous structure
60 is still on the collection device 56.
In another example, the fibrous structure 60 may be densified, for example
with a non-
random repeating pattern. In one example, the fibrous structure 60 may be
carried on a porous belt
and/or fabric, through a nip, for example a nip formed by a heated steel roll
and a rubber roll such
that the fibrous structure 60 is deflected into one or more of the pores of
the porous belt resulting
in localized regions of densification. Non-limiting examples of suitable
porous belts and/or fabrics
are commercially available from Albany International under the trade names
VeloStatTM,
ElectroTechT", and MicroStatTM. In one example, the nip applies a pressure of
at least 5 pounds
per lineal inch (ph) and/or at least 10 phi and/or at least 20 phi and/or at
least 50 phi and/or at least
80 phi.
The process for making fibrous structure 60 may be close coupled (where the
fibrous
structure is convolutedly wound into a roll prior to proceeding to a
converting operation) or directly
coupled (where the fibrous structure is not convolutedly wound into a roll
prior to proceeding to a
converting operation) with a converting operation to emboss, print, deform,
surface treat, or other
post-forming operation known to those in the art. For purposes of the present
invention, direct
coupling means that the fibrous structure 60 can proceed directly into a
converting operation rather
Date recue / Date received 2021-12-03
27
than, for example, being convolutedly wound into a roll and then unwound to
proceed through a
converting operation.
The process of the present invention may include preparing individual rolls of
fibrous
structure and/or sanitary tissue product comprising such fibrous structure(s)
that are suitable for
consumer use. The fibrous structure may be contacted by a bonding agent (such
as an adhesive
and/or dry strength agent), such that the ends of a roll of sanitary tissue
product according to the
present invention comprise such adhesive and/or dry strength agent.
The process may further comprise contacting an end edge of a roll of fibrous
structure with
a material that is chemically different from the filaments and fibers, to
create bond regions that
bond the fibers present at the end edge and reduce lint production during use.
The material may
be applied by any suitable process known in the art. Non-limiting examples of
suitable processes
for applying the material include non-contact applications, such as spraying,
and contact
applications, such as gravure roll printing, extruding, surface transferring.
In addition, the
application of the material may occur by transfer from contact of a log saw
and/or perforating blade
containing the material since, for example, the perforating operation, an edge
of the fibrous
structure that may produce lint upon dispensing a fibrous structure sheet from
an adjacent fibrous
structure sheet may be created.
The process of the present invention may include preparing individual rolls of
fibrous
structure and/or sanitary tissue product comprising such fibrous structure(s)
that are suitable for
consumer use.
Non-limiting Examples of Processes for Making a Fibrous Structure of the
Present Invention:
Example 1
A 47.5% : 27.5% : 20.0% : 5% blend of EquistarTM MF650x polypropylene:
Equistarlm
650W polypropylene : EquistarTm PH835 polypropylene : Polyvel S-1416 wetting
agent is dry
blended, to form a melt blend. The melt blend is heated to 475 F through a
melt extruder. A 15.5"
wide BiaxTM 12 row spinnerette with 192 nozzles per cross-direction inch,
commercially available
from Biax Fiberfilm Corporation, is utilized. 40 nozzles per cross-direction
inch of the 192 nozzles
have a 0.018" inside diameter while the remaining nozzles are unused for PP
delivery.
Approximately 0.19 grams per hole per minute (ghm) of the melt blend is
extruded from the open
nozzles to form meltblown filaments from the melt blend. Approximately 420
SCFM of
compressed air is heated such that the air exhibits a temperature of 395 F at
the spinnerette.
Approximately 500 grams / minute of KochTM 4825 semi-treated SSK pulp is
defibrillated through
Date recue / Date received 2021-12-03
28
a hammermill to form SSK wood pulp fibers (solid additive). Approximately 1600
SCFM of air
at 80 F and 80% relative humidity (RH) is drawn into the hammermill and
carries the pulp fibers
to a solid additive spreader. The solid additive spreader turns the pulp
fibers and distributes the
pulp fibers in the cross-direction such that the pulp fibers are injected into
the meltblown filaments
at a non-90 angle (a non-perpendicular fashion) for example at an angle of
less than 90 as
described herein through a 4" x 15" cross-direction (CD) slot. A forming box
surrounds the area
where the meltblown filaments and pulp fibers are commingled. This forming box
is designed to
reduce the amount of air allowed to enter or escape from this commingling
area. A forming vacuum
pulls air through a forming fabric thus collecting the commingled meltblown
filaments and pulp
fibers to form a fibrous structure. The forming vacuum is adjusted until an
additional 400 SCFM
of room air is drawn into the slot in the forming box. The fibrous structure
formed by this process
comprises about 75% by dry fibrous structure weight of pulp and about 25% by
dry fibrous
structure weight of meltblown filaments.
Optionally, a meltblown layer of the meltblown filaments can be added to one
or both sides
of the above formed fibrous structure. This addition of the meltblown layer
can help reduce the
lint created from the fibrous structure during use by consumers and is
preferably performed prior
to any thermal bonding operation of the fibrous structure. The meltblown
filaments for the exterior
layers can be the same or different than the meltblown filaments used on the
opposite layer or in
the center layer(s).
The fibrous structure may be convolutedly wound to form a roll of fibrous
structure. The
end edges of the roll of fibrous structure may be contacted with a material to
create bond regions.
Example 2
A 20%:27.5%47.5%:5% blend of Lyondell-BaseIITM PH835 polypropylene : Lyondell-
Basell MetoceneTM MF650W polypropylene: Exxon-MobilTm PP3546 polypropylene:
PolyyelTm
S-1416 wetting agent is dry blended, to form a melt blend. The melt blend is
heated to 400 F
through a melt extruder. A 15.5 inch wide Biax 12 row spinnerette with 192
nozzles per cross-
direction inch, commercially available from Biax Fiberfilm Corporation, is
utilized. 40 nozzles
per cross-direction inch of the 192 nozzles have a 0.018 inch inside diameter
while the remaining
nozzles are solid, i.e. there is no opening in the nozzle. Approximately 0.19
grams per hole per
minute (ghm) of the melt blend is extruded from the open nozzles to form
meltblown filaments
from the melt blend. Approximately 415 SCFM of compressed air is heated such
that the air
exhibits a temperature of 395 F at the spinnerette. Approximately 475 g /
minute of a blend of
Date recue / Date received 2021-12-03
29
70% Golden IsleTM (from Georgia Pacific) 4825 semi-treated SSK pulp and 30%
Eucalyptus is
defibrillated through a hammermill to form SSK and Euc wood pulp fibers (solid
additive). Air
at 85-90 F and 85% relative humidity (RH) is drawn into the hammermill.
Approximately 2400
SCFM of air carries the pulp fibers to two solid additive spreaders. The solid
additive spreaders
turn the pulp fibers and distribute the pulp fibers in the cross-direction
such that the pulp fibers are
injected into the meltblown filaments at a non-90 angle (a non-perpendicular
fashion) for example
at an angle of less than 90 as described herein through a 4 inch x 15 inch
cross-direction (CD)
slot. The two solid additive spreaders are on opposite sides of the meltblown
filaments facing one
another. A forming box surrounds the area where the meltblown filaments and
pulp fibers are
commingled. This forming box is designed to reduce the amount of air allowed
to enter or escape
from this commingling area. A forming vacuum pulls air through a collection
device, such as a
patterned belt, thus collecting the commingled meltblown filaments and pulp
fibers to form a
fibrous structure. The fibrous structure formed by this process comprises
about 75% by dry fibrous
structure weight of pulp and about 25% by dry fibrous structure weight of
meltblown filaments.
Optionally, a meltblown layer of the meltblown filaments can be added to one
or both sides
of the above formed fibrous structure. This addition of the meltblown layer
can help reduce the
lint created from the fibrous structure during use by consumers and is
preferably performed prior
to any thermal bonding operation of the fibrous structure. The meltblown
filaments for the exterior
layers can be the same or different than the meltblown filaments used on the
opposite layer or in
the center layer(s).
The fibrous structure, while on a patterned belt (e.g. Velostat 170PC 740 by
Albany
International), is calendered at about 40 PLI (Pounds per Linear CD inch) with
a metal roll facing
the fibrous structure and a rubber coated roll facing the patterned belt. The
steel roll having an
internal temperature of 300sF as supplied by an oil heater.
Optionally, the fibrous structure can be adhered to a metal roll, or creping
drum, using
sprayed, printed, slot extruded (or other known methodology) creping adhesive
solution. The
fibrous structure is then creped from the creping drum and foreshortened.
Alternatively or in
addition to creping, the fibrous structure may be subjected to mechanical
treatments such as ring
rolling, gear rolling, embossing, rush transfer, tuft-generating operations,
and other similar fibrous
structure deformation operations.
Optionally, two or more plies of the fibrous structure can be embossed and/or
laminated
and/or thermally bonded together to form a multi-ply fibrous structure.
Date recue / Date received 2021-12-03
30
The fibrous structure may be convolutedly wound to form a roll of fibrous
structure. The end
edges of the roll of fibrous structure may be contacted with a material to
create bond regions.
Fibrous Structure
It has surprisingly been found that the fibrous structures of the present
invention exhibit a
pore volume distribution unlike pore volume distributions of other known
fibrous structures, for
example other known structured and/or textured fibrous structures. As set
forth below, references
to fibrous structures of the present invention are also applicable to sanitary
issue products
comprising one or more fibrous structures of the present invention.
The fibrous structures of the present invention have surprisingly been found
to exhibit
improved absorbent capacity and surface drying. In one example, the fibrous
structures comprise
a plurality of filaments and a plurality of solid additives, for example
fibers.
The fibrous structures of the present invention comprise a plurality of
filaments and
optionally, a plurality of solid additives, such as fibers.
The fibrous structures of the present invention may comprise any suitable
amount of
filaments and any suitable amount of solid additives. For example, the fibrous
structures may
comprise from about 10% to about 70% and/or from about 20% to about 60% and/or
from about
30% to about 50% by dry weight of the fibrous structure of filaments and from
about 90% to about
30% and/or from about 80% to about 40% and/or from about 70% to about 50% by
dry weight of
.. the fibrous structure of solid additives, such as wood pulp fibers.
The filaments and solid additives of the present invention may be present in
fibrous
structures according to the present invention at weight ratios of filaments to
solid additives of from
at least about 1:1 and/or at least about 1:1.5 and/or at least about 1:2
and/or at least about 1:2.5
and/or at least about 1:3 and/or at least about 1:4 and/or at least about 1:5
and/or at least about 1:7
and/or at least about 1:10.
In one example, the solid additives, for example wood pulp fibers, may be
selected from
the group consisting of softwood kraft pulp fibers, hardwood pulp fibers, and
mixtures thereof
Non-limiting examples of hardwood pulp fibers include fibers derived from a
fiber source selected
from the group consisting of: Acacia, Eucalyptus, Maple, Oak, Aspen, Birch,
Cottonwood, Alder,
Ash, Cherry, Elm, Hickory, Poplar, Gum, Walnut, Locust, Sycamore, Beech,
Catalpa, Sassafras,
Gmelina, Albizia, Anthocephalus, and Magnolia. Non-limiting examples of
softwood pulp fibers
include fibers derived from a fiber source selected from the group consisting
of: Pine, Spruce, Fir,
Tamarack, Hemlock, Cypress, and Cedar. In one example, the hardwood pulp
fibers comprise
Date recue / Date received 2021-12-03
31
tropical hardwood pulp fibers. Non-limiting examples of suitable tropical
hardwood pulp fibers
include Eucalyptus pulp fibers, Acacia pulp fibers, and mixtures thereof.
In one example, the hardwood pulp fibers exhibit a Kajaani fiber cell wall
thickness of less
than 5.98 and/or less than 5.96
and/or less than 5.94 [i.m. In another example, the hardwood
pulp fibers exhibit a Kajaani fiber width of less than 14.15 and/or less
than 14.10 and/or
less than 14.05 and/or less than 14.00
and/or less than 13.95 and/or less than 13.90 lam.
In another example, the hardwood pulp fibers exhibit a Kajaani millions of
fibers/gram of greater
than 24 millions of fibers/gram and/or greater than 20.5 millions of
fibers/gram and/or greater than
21 millions of fibers/gram and/or greater than 21.5 millions of fibers/gram
and/or greater than 22
millions of fibers/gram and/or greater than 22.5 millions of fibers/gram
and/or greater than 23
millions of fibers/gram and/or greater than 23.5 millions of fibers/gram
and/or greater than 24
millions of fibers/gram and/or greater than 24.5 millions of fibers/gram
and/or greater than 25
millions of fibers/gram. In still another example, the hardwood pulp fibers
exhibit a Kajaani fiber
cell wall thickness of less than 6.15 and/or
less than 6.10 and/or less than 6.05 and/or
less than 6.00 and/or less than
5.98 p.m and/or less than 5.96 and/or less than 5.94 [i.m. In
even still another example, the hardwood pulp fibers exhibit a ratio of
Kajaani fiber length (m) to
Kajaani fiber width (m) of less than 45 and/or less than 43 and/or less than
41. In still yet another
example, the hardwood pulp fibers exhibit a ratio of Kajaani fiber coarseness
of less than 0.074
mg/m and/or less than 0.0735 mg/m
In one example, the wood pulp fibers comprise softwood pulp fibers derived
from the kraft
process and originating from southern climates, such as Southern Softwood
Kraft (SSK) pulp
fibers. In another example, the wood pulp fibers comprise softwood pulp fibers
derived from the
kraft process and originating from northern climates, such as Northern
Softwood Kraft (NSK) pulp
fibers.
The wood pulp fibers present in the fibrous structure may be present at a
weight ratio of
softwood pulp fibers to hardwood pulp fibers of from 100:0 and/or from 90:10
and/or from 86:14
and/or from 80:20 and/or from 75:25 and/or from 70:30 and/or from 60:40 and/or
about 50:50
and/or to 0:100 and/or to 10:90 and/or to 14:86 and/or to 20:80 and/or to
25:75 and/or to 30:70
and/or to 40:60. In one example, the weight ratio of softwood pulp fibers to
hardwood pulp fibers
.. is from 86:14 to 70:30.
In one example, the fibrous structures of the present invention comprise one
or more
trichomes. Non-limiting examples of suitable sources for obtaining trichomes,
especially trichome
fibers, are plants in the Labiatae (Lamiaceae) family commonly referred to as
the mint family.
Date recue / Date received 2021-12-03
32
Examples of suitable species in the Labiatae family include Stachys byzantina,
also known as
Stachys lanata commonly referred to as lamb's ear, woolly betony, or
woundwort. The term
Stachys byzantina as used herein also includes cultivars Stachys byzantina
'Primrose Heron',
Stachys byzantina 'Helene von Stein' (sometimes referred to as Stachys
byzantina 'Big Ears'),
Stachys byzantina 'Cotton Boll', Stachys byzantina 'Variegated' (sometimes
referred to as Stachys
byzantina 'Striped Phantom'), and Stachys byzantina 'Silver Carpet'.
In one example, the fibrous structures of the present invention exhibit a pore
volume
distribution such that greater than 8% and/or at least 10% and/or at least 14%
and/or at least 18%
and/or at least 20% and/or at least 22% and/or at least 25% and/or at least
29% and/or at least 34%
and/or at least 40% and/or at least 50% of the total pore volume present in
the fibrous structures
exists in pores of radii of from 2.54m to 504m as measured by the Pore Volume
Distribution Test
Method described herein.
In another example, the fibrous structures of the present invention exhibit a
sled surface
drying time of less than 50 seconds and/or less than 45 seconds and/or less
than 40 seconds and/or
less than 35 seconds and/or 30 seconds and/or 25 seconds and/or 20 seconds as
measured by the
Sled Surface Drying Test Method described herein.
In yet another example, the fibrous structures of the present invention
exhibit a pore volume
distribution such that at least 2% and/or at least 9% and/or at least 10%
and/or at least 12% and/or
at least 17% and/or at least 18% and/or at least 28% and/or at least 32%
and/or at least 43% of the
total pore volume present in the fibrous structure exists in pores of radii of
from 91 pm to 140 m
as measured by the Pore Volume Distribution Test Method described herein.
In even yet another example, the fibrous structures of the present invention
exhibit a pore
volume distribution such that at least 2% and/or at least 9% and/or at least
10% and/or at least 12%
and/or at least 17% and/or at least 18% and/or at least 20% and/or at least
28% and/or at least 32%
.. and/or at least 43% of the total pore volume present in the fibrous
structure exists in pores of radii
of from 914m to 1201.im and/or exhibit a pore volume distribution such that
less than 50% and/or
less than 45% and/or less than 40% and/or less than 38% and/or less than 35%
and/or less than
30% of the total pore volume present in the fibrous structure exists in pores
of radii of from 101 im
to 200 p.m as measured by the Pore Volume Distribution Test Method described
herein. In one
example, the fibrous structures of the present invention exhibit a pore volume
distribution such that
at least 20% and/or at least 28% and/or at least 32% and/or at least 43% of
the total pore volume
present in the fibrous structure exists in pores of radii of from 914m to
1204m and exhibit a pore
volume distribution such that less than 40% and/or less than 38% and/or less
than 35% and/or less
Date recue / Date received 2021-12-03
33
than 30% of the total pore volume present in the fibrous structure exists in
pores of radii of from
1011Lim to 200 tm as measured by the Pore Volume Distribution Test Method
described herein.
In even yet another example, the fibrous structures of the present invention
exhibit a pore
volume distribution such that at least 2% and/or at least 9% and/or at least
10% and/or at least 12%
and/or at least 17% and/or at least 18% and/or at least 20% and/or at least
28% and/or at least 32%
and/or at least 43% of the total pore volume present in the fibrous structure
exists in pores of radii
of from 91[1m to 140m and/or exhibit a pore volume distribution such that less
than 50% and/or
less than 45% and/or less than 40% and/or less than 38% and/or less than 35%
and/or less than
30% of the total pore volume present in the fibrous structure exists in pores
of radii of from 101 im
to 200 pm and/or exhibit a pore volume distribution such that less than 50%
and/or less than 45%
and/or less than 40% and/or less than 38% and/or less than 35% and/or less
than 30% of the total
pore volume present in the fibrous structure exists in pores of radii of from
121[im to 200 lam as
measured by the Pore Volume Distribution Test Method described herein. In
another example, the
fibrous structures of the present invention exhibit a pore volume distribution
such that at least 43%
of the total pore volume present in the fibrous structure exists in pores of
radii of from 91[1m to
140[1m and exhibit a pore volume distribution less than 40% and/or less than
38% and/or less than
35% and/or less than 30% of the total pore volume present in the fibrous
structure exists in pores
of radii of from 101[1m to 200 pm and exhibit a pore volume distribution less
than 40% and/or less
than 38% and/or less than 35% and/or less than 30% of the total pore volume
present in the fibrous
structure exists in pores of radii of from 1211.1m to 200 lam as measured by
the Pore Volume
Distribution Test Method described herein.
In even yet another example, the fibrous structures of the present invention
exhibit a pore
volume distribution such that at least 2% and/or at least 9% and/or at least
10% and/or at least 12%
and/or at least 17% and/or at least 18% and/or at least 20% and/or at least
28% and/or at least 32%
and/or at least 43% of the total pore volume present in the fibrous structure
exists in pores of radii
of from 91[1m to 140[1m and/or exhibit a pore volume distribution such that
less than 50% and/or
less than 45% and/or less than 40% and/or less than 38% and/or less than 35%
and/or less than
30% of the total pore volume present in the fibrous structure exists in pores
of radii of from 101 im
to 200 lam as measured by the Pore Volume Distribution Test Method described
herein. In another
example, the fibrous structures of the present invention exhibit a pore volume
distribution such that
at least 43% of the total pore volume present in the fibrous structure exists
in pores of radii of from
91[1m to 140tim and exhibit a pore volume distribution less than 40% and/or
less than 38% and/or
Date recue / Date received 2021-12-03
34
less than 35% and/or less than 30% of the total pore volume present in the
fibrous structure exists
in pores of radii of from 101[1m to 200 [tm as measured by the Pore Volume
Distribution Test
Method described herein.
In one example, the fibrous structure of the present invention exhibits at
least a bi-modal
pore volume distribution (i.e., the pore volume distribution exhibits at least
two modes). A fibrous
structure according to the present invention exhibiting a bi-modal pore volume
distribution
provides beneficial absorbent capacity and absorbent rate as a result of the
larger radii pores and
beneficial surface drying as a result of the smaller radii pores.
In still another example, the fibrous structures of the present invention
exhibit a VFS of
greater than 5 g/g and/or greater than 6 g/g and/or greater than 8 g/g and/or
greater than 10 g/g
and/or greater than 11 g/g as measured by the VFS Test Method described
herein.
In still another example, the fibrous structures of the present invention
exhibit a HFS of
greater than 5 g/g and/or greater than 6 g/g and/or greater than 8 g/g and/or
greater than 10 g/g
and/or greater than 11 g/g as measured by the HFS Test Method described
herein.
In one example, the fibrous structure of the present invention, alone or as a
ply of fibrous
structure in a multi-ply fibrous structure, comprises at least one surface
(interior or exterior surface
in the case of a ply within a multi-ply fibrous structure) that consists of a
layer of filaments.
In still another example, the fibrous structure of the present invention,
alone or as a ply of
fibrous structure in a multi-ply fibrous structure, comprises a scrim
material.
In another example, the fibrous structure of the present invention, alone or
as a ply of
fibrous structure in a multi-ply fibrous structure, comprises a creped fibrous
structure. The creped
fibrous structure may comprise a fabric creped fibrous structure, a belt
creped fibrous structure,
and/or a cylinder creped, such as a cylindrical dryer creped fibrous
structure. In one example, the
fibrous structure may comprise undulations and/or a surface comprising
undulations.
In yet another example, the fibrous structure of the present invention, alone
or as a ply of
fibrous structure in a multi-ply fibrous structure, comprises an uncreped
fibrous structure.
In still another example, the fibrous structure of the present invention,
alone or as a ply of
fibrous structure in a multi-ply fibrous structure, comprises a foreshortened
fibrous structure.
The fibrous structures of the present invention and/or any sanitary tissue
products comprising such
fibrous structures may be subjected to any post-processing operations such as
embossing
operations, printing operations, tuft-generating operations, thermal bonding
operations, ultrasonic
bonding operations, perforating operations, surface treatment operations such
as application of
lotions, silicones and/or other materials and mixtures thereof
Date recue / Date received 2021-12-03
35
Non-limiting examples of suitable polypropylenes for making the filaments of
the present
invention are commercially available from Lyondell-Basell and Exxon-Mobil.
Any hydrophobic or non-hydrophilic materials within the fibrous structure,
such as
polypropylene filaments, may be surface treated and/or melt treated with a
hydrophilic modifier.
Non-limiting examples of surface treating hydrophilic modifiers include
surfactants, such as Triton
XlOOTM. Non-limiting examples of melt treating hydrophilic modifiers that are
added to the melt,
such as the polypropylene melt, prior to spinning filaments, include
hydrophilic modifying melt
additives such as VW351 and/or S-1416 commercially available from Polyvel,
Inc. and Irgasurfrm
commercially available from Ciba. The hydrophilic modifier may be associated
with the
hydrophobic or non-hydrophilic material at any suitable level known in the
art. In one example,
the hydrophilic modifier is associated with the hydrophobic or non-hydrophilic
material at a level
of less than about 20% and/or less than about 15% and/or less than about 10%
and/or less than
about 5% and/or less than about 3% to about 0% by dry weight of the
hydrophobic or non-
hydrophilic material.
The fibrous structures of the present invention may include optional
additives, each, when
present, at individual levels of from about 0% and/or from about 0.01% and/or
from about 0.1%
and/or from about 1% and/or from about 2% to about 95% and/or to about 80%
and/or to about
50% and/or to about 30% and/or to about 20% by dry weight of the fibrous
structure. Non-limiting
examples of optional additives include permanent wet strength agents,
temporary wet strength
agents, dry strength agents such as carboxymethylcellulose and/or starch,
softening agents, lint
reducing agents, opacity increasing agents, wetting agents, odor absorbing
agents, perfumes,
temperature indicating agents, color agents, dyes, osmotic materials,
microbial growth detection
agents, antibacterial agents and mixtures thereof
The fibrous structure of the present invention may itself be a sanitary tissue
product. It may
be convolutedly wound about a core to form a roll. It may be combined with one
or more other
fibrous structures as a ply to form a multi-ply sanitary tissue product. In
one example, a co-formed
fibrous structure of the present invention may be convolutedly wound about a
core to form a roll
of co-formed sanitary tissue product. The rolls of sanitary tissue products
may also be coreless.
TEST METHODS
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 C 1.0 C and a
relative humidity of 50%
Date recue / Date received 2021-12-03
36
2% for a minimum of 12 hours prior to the test. All plastic and paper board
packaging articles
of manufacture, if any, must be carefully removed from the samples 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. Except where noted all
tests are conducted in
such conditioned room, all tests are conducted under the same environmental
conditions and in
such conditioned room. Discard any damaged product. Do not test samples that
have defects such
as wrinkles, tears, holes, and like. All instruments are calibrated according
to manufacturer's
specifications. Samples conditioned as described herein are considered dry
samples (such as "dry
fibrous structures") for purposes of this invention.
Pore Volume Distribution Test Method
Pore Volume Distribution measurements are made
on a
TRI/AutoporosimeterTm(TRI/Princeton Inc. of Princeton, NJ). The
TRI/Autoporosimeter is an
automated computer-controlled instrument for measuring pore volume
distributions in porous
materials (e.g., the volumes of different size pores within the range from 1
to 1000 pm effective
pore radii). Complimentary Automated Instrument Software, Release 2000.1, and
Data Treatment
Software, Release 2000.1 is used to capture, analyze and output the data. More
information on the
TRI/Autoporosimeter, its operation and data treatments can be found in The
Journal of Colloid and
Interface Science 162 (1994), pgs 163-170.
As used in this application, determining Pore Volume Distribution involves
recording the
increment of liquid that enters a porous material as the surrounding air
pressure changes. A sample
in the test chamber is exposed to precisely controlled changes in air
pressure. The size (radius) of
the largest pore able to hold liquid is a function of the air pressure. As the
air pressure increases
(decreases), different size pore groups drain (absorb) liquid. The pore volume
of each group is
equal to this amount of liquid, as measured by the instrument at the
corresponding pressure. The
effective radius of a pore is related to the pressure differential by the
following relationship.
Pressure differential = R2) y cos01 / effective radius
where y = liquid surface tension, and = contact angle.
Typically pores are thought of in terms such as voids, holes or conduits in a
porous material.
It is important to note that this method uses the above equation to calculate
effective pore radii
based on the constants and equipment controlled pressures. The above equation
assumes uniform
cylindrical pores. Usually, the pores in natural and manufactured porous
materials are not perfectly
cylindrical, nor all uniform. Therefore, the effective radii reported here may
not equate exactly to
Date recue / Date received 2021-12-03
37
measurements of void dimensions obtained by other methods such as microscopy.
However, these
measurements do provide an accepted means to characterize relative differences
in void structure
between materials.
The equipment operates by changing the test chamber air pressure in user-
specified
increments, either by decreasing pressure (increasing pore size) to absorb
liquid, or increasing
pressure (decreasing pore size) to drain liquid. The liquid volume absorbed at
each pressure
increment is the cumulative volume for the group of all pores between the
preceding pressure
setting and the current setting.
In this application of the TRI/Autoporosimeter, the liquid is a 0.2 weight %
solution of
octylphenoxy polyethoxy ethanol (Triton X-100 from Union Carbide Chemical and
Plastics Co. of
Danbury, CT.) in distilled water. The instrument calculation constants are as
follows: p (density)
= 1 g/cm3; y (surface tension) = 31 dynes/cm; cos = 1. A 1.2 p.m Millipore
Glass Filter (Millipore
Corporation of Bedford, MA; Catalog # GSWP09025) is employed on the test
chamber's porous
plate. A plexiglass plate weighing about 24 g (supplied with the instrument)
is placed on the
sample to ensure the sample rests flat on the Millipore Filter. No additional
weight is placed on
the sample.
The remaining user specified inputs are described below. The sequence of pore
sizes
(pressures) for this application is as follows (effective pore radius in pm):
1, 2.5, 5, 10, 15, 20, 30,
40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 225, 250, 275, 300, 350,
400, 500, 600, 800,
1000. This sequence starts with the sample dry, saturates it as the pore
settings increase (typically
referred to with respect to the procedure and instrument as the 1st.
absorption).
In addition to the test materials, a blank condition (no sample between
plexiglass plate and
Millipore Filter) is run to account for any surface and/or edge effects within
the chamber. Any
pore volume measured for this blank run is subtracted from the applicable pore
grouping of the test
sample.
This data treatment can be accomplished manually or with the available
TRI/Autoporosimeter Data Treatment Software, Release 2000.1.
Percent (% ) Total Pore Volume is a percentage calculated by taking the volume
of fluid in
the specific pore radii range divided by the Total Pore Volume. The
TRI/Autoporosimeter outputs
the volume of fluid within a range of pore radii. The first data obtained is
for the "2.5 micron"
pore radii which includes fluid absorbed between the pore sizes of 1 to 2.5
micron radius. The
next data obtained is for "5 micron" pore radii, which includes fluid absorbed
between the
2.5micron and 5 micron radii, and so on. Following this logic, to obtain the
volume held within
the range of 91-140 micron radii, one would sum the volumes obtained in the
range titled "100
Date recue / Date received 2021-12-03
38
micron", "110 micron", "120 micron", "130 micron", and finally the "140
micron" pore radii
ranges. For example, % Total Pore Volume 91-140 micron pore radii = (volume of
fluid between
91-140 micron pore radii) / Total Pore Volume.
Basis Weight Test Method
Basis weight of a fibrous structure sample is measured by selecting twelve
(12) individual
fibrous structure samples and making two stacks of six individual samples
each. If the individual
samples are connected to one another vie perforation lines, the perforation
lines must be aligned
on the same side when stacking the individual samples. A precision cutter is
used to cut each stack
into exactly 3.5 in. x 3.5 in. squares. The two stacks of cut squares are
combined to make a basis
weight pad of twelve squares thick. The basis weight pad is then weighed on a
top loading balance
with a minimum resolution of 0.01 g. The top loading balance must be protected
from air drafts
and other disturbances using a draft shield. Weights are recorded when the
readings on the top
loading balance become constant. The Basis Weight is calculated as follows:
Basis Weight = Weight of basis weight pad (g) x 3000 ft2
(lbs/3000 ft2) 453.6 g/lbs x 12 samples x [12.25 in2 (Area of basis weight
pad)/144 in21
Basis Weight = Weight of basis weight pad (g) x 10,000 cm2/m2
(g/m2) 79.0321 cm2 (Area of basis weight pad) x 12 samples
The level of filaments present in a fibrous structure having an initial basis
weight can be
determined by measuring the filament basis weight of a fibrous structure by
using the Basis Weight
Test Method after separating all non-filament materials from a fibrous
structure. Different
approaches may be used to achieve this separation. For example, non-filament
material may be
dissolved in an appropriate dissolution agent, such as sulfuric acid or
Cadoxen, leaving the
filaments intact with their mass essentially unchanged. The filaments are then
weighed. The
weight percentage of filaments present in the fibrous structure is then
determined by the equation:
% wt. Filaments = 100 * (Filament Mass/Initial Basis Weight of Fibrous
Structure)
Date recue / Date received 2021-12-03
39
The % wt. Solid Additives present in the fibrous structure can then be
determined by subtracting
the % wt. Filaments from 100% to arrive at the % wt. Solid Additives.
MD Basis Weight Test Method
The machine direction (MD) Basis Weight of a fibrous structure sample is
measured by
using a precision cutter to cut thirty-five single ply 100mm x 50mm rectangle
samples. Each
sample should be weighed individually. Each 100mm x 50mm rectangle sample are
to be
oriented so that the 100mm axis is in the cross-direction (CD), from the same
CD position, and
be located in the MD as close as possible to each other, so that the intent of
capturing the
immediate MD basis weight variation at any CD location is achieved. The weight
of the
rectangle samples are then weighed on atop loading balance with a minimum
resolution of 0.01
g. The top loading balance must be protected from air drafts and other
disturbances using a draft
shield. The weights of the rectangle samples are recorded when the readings on
the top loading
balance become constant. The Basis Weight (BW) of the fibrous structure is
calculated as
follows:
BW = Weight of basis weight sample (g) x 10,000 cm2/m2
(g/m2) 50 cm2 (Area of basis weight sample)
The MD Basis Weight Coefficient of Variation ("MD Basis Weight Variation" or
"MD
Basis Weight COV") is defined as the standard deviation of basis weights
divided by the average
basis weights as measured according to the MD Basis Weight Test Method
described above for
thirty-five 50mm (MD) x 100mm (CD) fibrous structure samples as measured
according to the MD
Basis Weight Test Method described above.
Horizontal Full Sheet (HFS) Test Method
The Horizontal Full Sheet (HFS) 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 horizontal
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
Date recue / Date received 2021-12-03
40
absorbed by the sample. When evaluating different fibrous structure samples,
the same size of
fibrous structure is used for all samples tested.
The apparatus for determining the HFS capacity of fibrous structures comprises
the
following:
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/benchtop 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.
2) A sample support rack (Figs. 9A and 9B) and sample support rack cover
(Figs. 10A and
10B) 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 as shown
in Fig. 9A. The
size of the support rack and cover is such that the sample size can be
conveniently placed between
the two.
The HFS test is performed in an environment maintained at 23 1 C and 50 2%
relative
humidity. A water reservoir or tub is filled with distilled water at 23 1 C
to a depth of 3 inches
(7.6 cm).
Eight 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.
The sample, support rack and cover are allowed to drain horizontally for 120 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 0.01g. This is the wet weight of the sample.
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 horizontal absorbent
capacity (HAC) is
Date recue / Date received 2021-12-03
41
defined as: absorbent capacity = (wet weight of the sample - dry weight of the
sample) / (dry weight
of the sample) and has a unit of gram/gram.
Vertical Full Sheet (VFS) Test Method
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.
The apparatus for determining the VFS capacity of fibrous structures comprises
the
following:
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/benchtop weighing. The balance should also have a
special balance pan
lobe able to handle the size of the sample tested (i.e.; a fibrous structure
sample of about 11 in. by
11 in.). The balance pan can be made out of a variety of materials. Plexiglass
is a common material
used.
2) A sample support rack (Figs. 9A and 9B) and sample support rack cover
(Figs. 10A and
10B) is also required. Both the rack and cover are comprised of a lightweight
metal frame, strung
with 0.012 in. diameter monofilament so as to form a grid as shown in Fig. 9A.
The size of the
support rack and cover is such that the sample size can be conveniently placed
between the two.
The VFS test is performed in an environment maintained at 23 1 C and 50 2%
relative
humidity. A water reservoir or tub is filled with distilled water at 23 1 C
to a depth of 3 inches.
Eight 7.5 inch x 7.5 inch to 11 inch x 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.
Date recue / Date received 2021-12-03
42
After the sample is submerged for 60 seconds, the sample support rack and
cover are gently raised
out of the reservoir.
The sample, support rack and cover are allowed to drain vertically (at angle
greater than
60 but less than 90 from horizontal) for 60 5 seconds, taking care not to
excessively shake or
vibrate the sample. While the sample is draining, the rack cover is removed
and 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 0.01g. This is the wet
weight of the sample.
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
in plane 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.
Sled Surface Drying Test Method
The sled surface drying test is performed using constant rate of extension
tensile tester
with computer interface (a suitable instrument is the MTS AllianceTM using
Testvvorks 4 Software,
as available from MTS Systems Corp., Eden Prairie, MN) using a load cell for
which the forces
measured are within 10% to 90% of the limit of the cell. The instrument is
fitted with a coefficient
of friction fixture and sled as depicted in ASTM D 1894-01 figure lc. (a
suitable fixture is the
Coefficient of Friction Fixture and Sled available as #769-3000 from Thwing-
Albert, West Berlin,
NJ). The movable (upper) pneumatic jaw is fitted with rubber faced grips,
suitable to securely
clamp the sled's lead wire. The target surface is a black Formica brand
laminate #909-58 which
has a contact angle (water) of 66 5 degrees. All testing is performed in a
conditioned room
maintained at 23 C 2 C and 50 % 2 % relative humidity. The test area is
substantially free
from air drafts from doors, ventilation systems, or lab traffic. The target
surface at the observation
zone is illuminated at 7.5 lumens 0.2 lumens.
Referring to Figure 11, the lower fixture 502, consist of a stage 505, 40 in
long by 6 in wide
by 0.25 in thick, mounted via a shaft 507 designed to fit the lower mount of
tensile tester. A locking
collar 508 is used to stabilize the platform and maintain horizontal
alignment. The stage is covered
with the Formica target 506 which is 38 in long by 6 in wide by 0.128 in
thick. A pulley 509 is
attached to the stage 505 which directs the wire lead 504 from the sled 503
into the grip faces of
Date recue / Date received 2021-12-03
43
the upper fixture 500. Time is measured using a lab timer capable of measuring
to the nearest 0.1
sec. and certified traceable to NIST.
Condition the sample at 23 C 2 C and 50 % 2 % relative humidity for 2
hours prior
to testing. Die cut a specimen 127 mm lmm long in the machine direction and 64
mm lmm
wide in the cross direction. Load the specimen onto the sled 503 by feeding
the specimen through
the spring-loaded bar grips. Once clamped, the specimen is without slack and
completely covers
the bottom surface of the sled 503. The acceptable weight of the sled plus
sample is 200 g 2g.
Set the position of the tensile tester crosshead such that the centers of the
grip faces are
approximately 1.5 in above the top of the pulley. Place the distal end of the
sled 503 flush with the
distal edge of the target surface 506 as shown in Figure 11. The sled should
be centered along the
longitudinal center line of the target. Attach the lead wire 504 first to the
sled 503 Feed the other
end of the wire lead 504 around the pulley 509 and then between the grip faces
of the upper fixture.
Zero the load cell. Gently pull the lead wire 504 until a force of 20 5 gram
force is read on the
load cell. Close the grip faces. Program the tensile tester to move the
crosshead for 36 in at a rate
of 400 in/min.
Clean the Formica target with 2-propanol and allow the surface to dry. With a
calibrated
pipette, deposit 0.5 mL of distilled water onto the target centered along the
longitudinal axis of the
target and 8 in from the distal edge of the target. The diameter of the water
should not exceed 0.75
inch (for convenience a circle 0.75 inch in diameter can be marked at the
site). Zero the crosshead
and the timer. Simultaneously start the timer and begin the test.
After the sled movement has ceased, observe the evaporation of the liquid
streak. The
observer should monitor a 1 in wide observation zone 511, located between 28
to 29 inches from
the distal edge of the target 506, while at an observation angle of
approximately 45 degrees from
the horizontal plane of the platform 505. The timer is stopped when all signs
of the water have
disappeared. Record the Sled Surface Drying Time to the nearest 0.1 sec.
Testing is repeated for a total of 20 replicates for each sample. Clean the
surface every five
specimen or when a new sample is to be tested. The data set can be evaluated
using the Grub's T
test (Tcrit < 90%) for outliers, but no more than 3 replicates can be
discarded. If more than 3
outliers exist, a second set of 20 replicates should be tested. Average the
replicate samples and
report the Sled Surface Drying Time to the nearest 0.1 sec.
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
Date recue / Date received 2021-12-03
44
surrounding that value. For example, a dimension disclosed as "40 mm" is
intended to mean "about
40 mm."
The citation of any document, 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 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
cited herein, the meaning or definition assigned to that term in this document
shall govern.
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.
Date recue / Date received 2021-12-03
