Note: Descriptions are shown in the official language in which they were submitted.
CA 02588743 2007-05-29
FIBROUS STRUCTURE HAVING INCREASED SURFACE AREA AND
PROCESS FOR MAKING SAME
FIELD OF THE INVENTION
The present invention is related to processes for making strong, soft,
absorbent fibrous webs, such as, for example, paper webs. More particularly,
this invention is concemed with structured fibrous webs, equipment used to
make
such structured fibrous webs, and processes therefor.
BACKGROUND OF THE INVENTION
Products made from a fibrous web are used for a variety of purposes. For
example, paper towels, facial tissues, toilet tissues, napkins, and -the like
are in
constant use in modern industrialized societies. The large demand for such
paper products has created a demand for improved versions of the products. If
the paper products such as paper towels, facial tissues, napkins, toilet
tissues,
mop heads, and the like are to perform their intended tasks and to find wide
acceptance, they must possess certain physical characteristics.
Among the more important of these characteristics are strength, softness,
and absorbency. Strength is the ability of a paper web to retain its physical
integrity during use. Softness is the pleasing tactile sensation consumers
perceive when they use the paper for its intended purposes. Absorbency is the
characteristic of the paper that allows the paper to take up and retain
fluids,
particulady water and aqueous solutions and suspensions. Important not only is
the absolute quantity of fluid a given amount of paper will hold, but also the
rate
at which the paper will absorb the fluid.
Through-air drying papermaking belts comprising a reinforcing element and
a resinous framework, and/or fibrous webs made using these belts are known
CA 02588743 2007-05-29
and described, for example, in the following commonly assigned U.S. Patents,
the disclosures of which are incorporated herein by reference: 4,514,345,
issued
April 30, 1985 to Johnson et al.; 4,528,239, issued July 9, 1985 to Trokhan;
4,529,480 issued July 16, 1985 to Trokhan; 4,637,859 issued Jan. 20, 1987 to
Trokhan; 5,098,522, issued March 24, 1992 to Smurkoski, et al.; 5,245,025
issued Sep. 14, 1993 to Trokhan et at.; 5,260,171, issued Nov. 9, 1993 to
Smurkoski et al.; 5,275,700, issued Jan. 4, 1994 to Trokhan; 5,328,565, issued
Juty 12, 1994 to Rasch et al.; 5,334,289, issued Aug. 2, 1994 to Trokhan et
al.;
5,431,786, issued July 11, 1995 to Rasch et al.; 5,496,624, issued March 5,
lo 1996 to Stelljes, Jr. et al.; 5,500,277, issued March 19, 1996 to Trokhan
et al.;
5,514,523, issued May 7, 1996 to Trokhan et ai.; 5,527,428 issued June 18,
1996 to Trokhan et al.; 5,554,467, issued Sept. 10, 1996, to Trokhan et al.;
5,566,724, issued Oct. 22, 1996 to Trokhan et al.; 5,624,790, issued April 29,
1997 to Trokhan et al.; 5,628,876 issued May 13, 1997 to Ayers et al.;
5,679,222 issued Oct. 21, 1997 to Rasch et al.; 5,714,041 issued Feb. 3, 1998
to Ayers et al.; 5,900,122 issued May 4, 1999 to Huston; and 5,948,210 issued
September 7, 1999 to Huston.
In the aforementioned belts of prior art the resinous framework is joined to
the fluid-permeable reinforcing element (such as, for example, a woven
structure,
or a felt). The resinous framework may be continuous, semi-continuous,
comprise a plurality of discrete protuberances, or any combination thereof.
The
resinous framework extends outwardly from the reinforcing element to form a
web-side of the belt (i. e., the surface upon which the web is disposed during
a
papermaking process), a backside opposite to the web-side, and deflection
conduits extending therebetween. The deflection conduits provide spaces into
which papermaking fibers deflect under appiication of a pressure differential
during a papermaking process. Because of this quality, such papermaking belts
are also known in the art as "deflection members." The terms "papermaking
belt"
and "deflection member" may be used herein interchangeably.
2
CA 02588743 2007-05-29
Papers produced on such deflection members, disclosed in the
aforementioned patents, are generally characterized by having at least two
physically distinct regions: a region having a first elevation and typically
having a
relatively high density, and a region extending from the first region to a
second
elevation and typically having a relatively low density. The first region is
typically
formed from the fibers that have not been deflected into tiie deflection
conduits,
and the second region is typically formed from the fibers deflected into the
deflection conduits of the deflection member. The papers made using the belts
having a continuous resinous framework and a plurality of discrete deflection
1 o conduits dispersed therethrough comprise a continuous high-density network
region and a plurality of discrete low-density pillows (or domes), dispersed
throughout, separated by, and extending from the network region. The
continuous high-density network region is designed primarily to provide
strength,
while the plurality of the low-density pillows is designed primarily to
provide
softness and absorbency. Such belts have been used to produce commercially
successful products, such as, for example, Bounty paper towels, Charmin
toilet tissue, and Charmin Ultra toilet tissue, all produced and sold by the
instant assignee.
Typically, certain aspects of absorbency of a fibrous structure are highly
2o dependent on Its surface area. That is, for a given fibrous web (including
a fiber
composition, basis weight, etc.), the greater the web's surface area the
higher
the web's absorbency. In the structured webs, the low-density pillows,
dispersed
throughout the web, increase the web's surface area, thereby increasing the
web's absorbency. However, increasing the web's surface area by increasing
the area comprising the relatively iow-density pillows would result in
decreasing
the web's area comprising the relatively high-density network area that
Imparts
the strength. That is, increasing a ratio of the area comprising pillows
relative to
the area comprising the network would negatively affect the strength of the
paper, because the pillows have a relatively low intrinsic strength compared
to
the network regions. Therefore, it would be highly desirable to minimize the
3
CA 02588743 2007-05-29
trade-off between the surface area of the high-density network region
primarily
providing strerigth, and the surface area of the low-density region primarily
providing softness and absorbency.
Now, it has been discovered that the areas of the high-density region and
the low-density region can be effectively de-coupled in a fibrous structure,
e. g.,
that the surface area of the fibrous structure may be increased without
sacrificing
the strength of the fibrous structure. Specifically, it has been discovered
that the
surface area of the relatively low-density and absorbent pillows can be
sufficiently increased, without decreasing the area of the relatively high-
density
io network, by forming a novel fibrous structure using a deflection member of
the
present invention.
Accordingly, the present invention provides a novel strong, soft, and
absorbent fibrous structure and a process for making such a fibrous structure.
More specifically, the present invention provides a fibrous structure that has
at
least two regions: a first region having a first elevation and a second region
extending from the first region to define a second elevation, the second
region
having an increased surface area that enhances absorption qualities of the
fibrous structure.
The present invention further provides a fibrous structure wherein the
second region comprises fibrous domes and fibrous cantilever portions
laterally
extending from the domes. The fibrous cantilever portions increase the surface
area of the second region and form, in some embodiments, pockets comprising
substantially void spaces between the fibrous cantilever portions and the
first
region. These pockets are capable of receiving additional amounts of liquid
and
thus further increase absorbency of the fibrous structure.
The present invention also provides novel deflection members useful for
making such structured fibrous structures. More specifically, the present
invention provides deflection members comprising a patterned framework having
suspended portions that form voids into which the fibers can be deflected
during
4
CA 02588743 2007-05-29
a process for making the fibrous structure of the present invention, to form
the
fibrous cantilever portions.
The present invention further provides processes for making such
defiection members. In one embodiment, such a deflection member comprises a
multi-layer framework formed by at least two layers joined together in a face-
to-
face relationship. Each of the layers has a deflection conduit portion. The
deflection conduit portion of one layer is fluid-permeable and positioned such
that
portions of that layer correspond to the deflection conduits of the other
layer and
thus comprise a plurality of suspended portions.
In another embodiment, such a deflection member comprises a single-
layer framework wherein the suspended portions are formed by curing a layer of
a curable material through a novel mask of the present invention, comprising
regions of differential opacities.
In still another embodiment, the deflection member can be made by curing
a coating of the curable material through a novel mask of the present
invention,
comprising opaque regions and transparent regions, and a three-dimensional
topography.
The present invention further provides novel masks that can be used ih a
process for selective curing of a curable material, such as, for example, a
photosensitive resinous material. Such masks can also be used in making
deflection members of the present invention. More specifically, the present
invention provides a mask having a pattern of transparent regions and opaque
regions, the opaque regions comprising differential opacity.
The present invention also provides a mask in which the opaque regions
comprise a gradient opacity that graduafly changes in at least one direction.
The
present invention further provides a mask having a combined pattern comprising
a pattern of the transparent/opaque regions and a three-dimensional pattern of
protrusions extending from at least one side of the mask. The present
invention
also provides processes for making the masks of the present invention.
5
CA 02588743 2007-05-29
SUMMARY OF THE INVENTION
A deflection member of the present invention comprises a framework
having a web-side and a backside opposite to the web-side. The framework can
be made of any suitable material, including, without limitation, a resinous
materiai
5(such as, for example, a photosensitive resin), a plastic, a metal, metal-
impregnated polymers, etc. The back side of the framework defines an X-Y
plane. A thickness of the framework extends between the web-side and the
backside in a Z-direction perpendicular to the X-Y plane.
The framework comprises a plurality of bases extending from the X-Y
io plane in the Z-direction, and a plurality of suspended portions lateraily
extending
from the plurality of bases, wherein the suspended portions are elevated in
the Z-
direction from the X-Y plane to form void spaces between the X-Y plane and the
suspended portions. While the suspended portions themselves do not need to
be parallel to the X-Y plane, it is said that the suspended portions can
"extend" in
15 directions substantially parallel to the X-Y plane, to indicate that the
suspended.
portions extend '9aterally" from the bases (i. e. not paraiiel to the Z-
direction).
In one embodiment, the framework comprises a multi-layer (laminated)
structure formed by at least two layers: a first layer and a second layer
joined
together in a face-to-face relationship. Each of the layers has a top surface
and
2o a bottorn surface opposite to the top surface. Each of the layers can have
a
conduit portion comprising at least one deflection conduit extending in the Z-
direction from the top surface toward the bottom surface. The conduit portion
can extend from the top surface to the bottom surface through the entire
thickness of the layer. The bottom surface of the first layer forms the
backside of
2s the framework, and the top surface of the second layer forms the web-side
of the
framework. In a multi-layer embodiment of the deflection member (i. e., the
deflection member comprising a plurality of layers), the plurality of bases is
formed by the first layer.
According to the present invention, in an exemplary dual-layer deflection
so member (i. e., the deflection member comprising two layers), the second
layer
6
CA 02588743 2007-05-29
comprises a plurality of suspended portions elevated in the Z-direction from
the
X-Y plane to form void spaces between the X-Y plane and the suspended
portions. During a process of maidng a fibrous structure of the present
invention,
these void spaces can receive a plurality of fibers to form fibrous cantilever
s portions of the fibrous structure being formed.
The deflection member of the present invention can further comprise a
reinforcing element positioned between the web-side and at least a portion of
the
backside of the framework. The reinforcing element can be fluid-permeable,
fluid-impermeable, or partially fluid-permeable (meaning that some portions of
1o the reinforcing element may be fluid-permeable, while other portions
thereof may
be not). Examples of the reinforcing element include, without limitation, a
woven
element, a felt, a mesh wire, or a combination thereof. In the embodiment
comprising the multi-layer deflection member, the reinforcing element is
typically
positioned between the top surface of the first layer and at least a portion
of the
t5 bottom surface of the first layer, in which instance, the void spaces are
formed
between the reinforcing element and the suspended portions of the second
layer.
!n a multi-layer deflection member of the present invention, each of the
layers can comprise a substantially continuous framework, a substantially semi-
continuous framework, a plurality of discrete protuberances, or any
combination
20 thereof. In the exemplary dual-layer deflection member, examples of
combinations of the first and second lay rs include, without limitation, the
following: the deflection member, wherein the first layer comprises a
substantially
continuous patterned network defining a first plurality of discrete deflection
conduits therewithin, and the second layer comprises a substantially
continuous
25 patterned network defining a second plurality of discrete deflection
conduits
therewithin; the deflection member, wherein the first layer comprises a
substantially continuous pattemed network defining a first plurality of
discrete
deflection conduits therewithin, and the second layer comprises a semi-
continuous patterned network; the deflection member, wherein the first layer
30 comprises a substantially continuous patterned network defining a first
plurality of
7
CA 02588743 2007-05-29
discrete deflection conduits therewithin, and the second layer comprises a
plurality of discrete protuberances; the deflection member, wherein the first
layer
comprises a semi-continuous pattemed network, and the second layer comprises
a substantially continuous patterned network defining a second plurality of
discrete deflection conduits therewithin; the deflection member, wherein the
first
layer comprises a first semi-continuous patterned network, and the second
layer
comprises a second semi-continuous patterned network; the deflection member,
wherein the first layercomprises a semi-continuous patterned network, and the
second layer comprises a plurality of discrete protuberances; the deflection
io member, wherein the first layer comprises a plurality of discrete
protuberances,
and the second layer comprises a substantially continuous pattemed network
defining a second plurality of discrete deflection cbnduits therewithin; the
deflection member, wherein the first layer comprises a plurality of discrete
protuberances, and the second layer comprises a semi-continuous patterned
network; the deflection member, wherein the first layer comprises a first
plurality
of discrete protuberances, and the second layer comprises a second plurality
of
discrete protuberances.
The first layer andlor the second layer may be fluid-impermeable or
partially fluid-permeable. One example of the partially-fluid permeable layer
2o comprises a layer having a plurality of deflection conduits, wherein at
least some
of the deflection conduits are "closed' with a fluid-impermeable material.
A process for making the multi-layer deflection member comprises the
following steps:
forming a first layer having a'top surface and a bottom surface opposite to
the
top surface and defining an X-Y'plane, the first layer further having a first
conduit
portion extending between the top and bottom surfaces of the first layer;
forming a second layer having a top surface, a bottom surface opposite to the
top
surface, and a second conduit portion extending between the top and bottom
surfaces of the second layer; and
8
CA 02588743 2007-05-29
joining the first layer and the second layer together in a face-to-face
relationship
such that the top surface of the first layer faces the bottom surface of the
second
layer, wherein suspended portions of the second layer corresponding to the
first
conduit portion of the first layer are spaced at a distance from the X-Y plane
to
5- form void spaces between the X-Y plane and the suspended portions of the
second layer.
Either one or both of the first layer and the second layer may be formed by
a process comprising the following steps:
providing a coating of a liquid photosensitive resin supported by a forming
1o surface, the coating having a first thickness;
providing a source of curing radiation;
providing a mask having a pre-seiected pattem of transparent regions and
opaque regions therein and positioning the mask between the coating of the
liquid photosensitive resin and the source of curing radiation so that the
opaque
15 regions of the mask shield areas of the coating from the curing radiation
while the
transparent regions of the mask cause other areas of the coating to be
unshielded;
curing the unshieided areas of the coating by exposing the coating to the
curing
radiation through the mask while leaving the shielded areas of the coating
2o uncured, thereby forming a partly-formed layer,
removing substantially all uncured liquid photosensitive resin from the partly-
formed layer to leave a hardened resinous structure.
Optionally, a backing film may be provided and positioned between the
forming surface and the coating of a liquid photosensitive resin, to protect
the
2s forming surface from being contaminated by the liquid resin.
Alternatively or additionally to the process of making the layers described
herein above, each or both of the layers can be formed by providing a ply of a
predetermined thickness and forming therein a plurality of apertures of
predetermined shapes and according to a pre-selected pattern.
9
CA 02588743 2007-05-29
If the deflection member having the reinforcing element is desired, the
process may further include -steps of providing a suitable reinforcing element
supported by the forming surface, the reinforcing element having a lower side
facing the forming surface and an upper side opposite to the lower side, and
depositing the coating of a liquid photosensitive resin to the upper side of
the
reinforcing element.
Optionally, a thickness of the coating can be controlled by, for example, a
roll, a bar, a knife, or any other suitable means known in the art.
In one embodiment, the first and second layers are produced
io simultaneously on two respective forming surfaces and then are joined
together,
upon contact, in a press nip. According to one embodiment of the present
invention, a step of maintaining at least one of the top surface of the first
layer
and the bottom surface of the second layer in a partially uncured condition is
required to enable the first and second layers to join together upon contact
therebetween. Alternatively or additionally, the first and second layers can
be
joined by using an adhesive material. In one embodiment, the top surface of
the
first layer and/or the bottom surface of the second layer comprise(s) a
chemically-active ingredients causing or facilitating joining together of the
first
and second layers.
Each'of the suspended portions has a web-oriented surface comprising
the web-side of the framework, and a back surface opposite thereto. The void
spaces formed between the suspended portions and the X-Y plane, or between
the suspended portions and the reinforcing element, are formed - more
specifically - between the back surfaces of the suspended portions and either
the X-Y plane or the reinforcing element. A plurality of shapes and
configurations
of the back surfaces of the suspended portions are contemplated in the present
invention, all of which could be formed using one of the processes of the
present
invention. The suspended portion may have the back surface that is
substantially parallel to the X-Y plane. The suspended portion may also have
the
3o back surface that is not parallel to the web-oriented surface. The
suspended
CA 02588743 2007-05-29
portion may have curving, circular, "waving" back surfaces, or back surfaces
having different irregular shapes.
When viewed in a particular cross-section perpendicular to the X-Y plane,
the suspended portion may form either a"cantilever portion or a "bridge"
portion
in a cross-section. As used herein, the "cantilever" suspended portion means
the
suspended portion that has at least one free end in a cross-section
perpendicular
to the X-Y plane, while the "bridging" suspended portion is the suspended
portion
that interconnects (or bridges") at least two adjaeent bases in a cross-
section
perpendicular to the X-Y plane.
Analogously with the differential patterns of the layers, described above,
the web-side and the backside of the framework may comprise a substantially
continuous pattern, a substantiaily semi-continuous pattern, or a pattern
formed
by a plurality of discrete protuberances. The difference between the patterns
as
regards the framework as a whole and the patterns as regards the web-side or
backside surfaces of the framework is that in the context of the framework as
a
whole, the entire thickness of the framework is under consideration for the
purposes of continuity, semi-continuity, or discontinuity of the framework;
while
in the context of the web-side and the backside of the framework, only a
relevant
surface (of the web-side or the backside) is under consideration for the
purposes
of continuity, semi-continuity, or discontinuity of that relevant surface.
The framework as a whole, whether multi-layer or single-layer, may have a
fluid-permeable conduit portion extending from the web-side to the backside of
the framework. In one embodiment, at least one of the web-side and the
backside of the framework comprises a substantially continuous pattern of a
plurality of dlscrete openings dispersed therethrough, wherein the plurality
of
discrete openings comprises- a plurality of discrete deflection conduits. Some
of
the piurality of openings In the web-side or the backside may be c(osed by a
fluld-
impermeable material to form fluid-impermeable portions of the framework, if
desired.
11
CA 02588743 2007-05-29
Another embodiment of a process for making a deflection member, or a
single layer thereof, comprises the following steps:
providing a coating of a liquid photosensitive resin supported by a forming
surface, the coating having a top surface, a bottom surface opposite thereto
and
facing the forming surface, and a pre-selected first thickness defined between
the top and bottom surFaces;
providing a source of curing radiation;
providing a mask having transparent regions and opaque regions, the opaque
regions comprising at least first opaque regions and second opaque. regions,
the
1o first opaque regions having a first opacity, and the second opaque regions
having
a second opacity less that the first opacity;
positioning the mask between the coating and the source of curing radiation;
curing the liquid photosensitive resin through the mask, wherein the first
opaque
regions shield first areas of the coating from the curing radiation to
preclude
curing of the first areas of the coating through the first thickness of the
coating,
the second -opaque regions partially shield second areas of the coating to
allow
the curing radiation to cure the second area of the coating to a predetermined
second thickness less than the first thickness of the coating, and the
transparent
regions leave third areas of the coating unshielded to allow the curing
radiation to
cure the third areas through the first thickness of the coating, thereby
forming a
partly-formed deflection member; and
removing substantially all uncured liquid photosensitive resin from the partly-
formed deflection member to leave a hardened resinous structure which forms a
macroscopically monoplanar, patterned framework having a web-side formed
from the top surface of the coating, and a backside formed from the bottom
surface of the coating and defining an X-Y plane.
The resulting framework comprises a plurality of bases formed from the
third areas of the coating and a plurality of suspended portions formed from
the
second areas of the coating, wherein the suspended portions laterally extend
12
CA 02588743 2007-05-29
from the plurality of bases and are spaced from the X-Y plane to form void
spaces between the X-Y plane and the suspended portions.
A fibrous structure of the present invention comprises at least two regions:
a first plurality of micro-regions (or simply a first region) defining a first
plane and
having a first elevation, and a second plurality of micro-regions (or simply a
second region) outwardly extending from the first plane to define a second
elevation, wherein at least some of the second plurality of micro-regions
comprise a fibrous dome and a fibrous cantilever portion extending laterally
from
the dome at a second elevation. As used herein, the fibrous dome and the
io cantilever portion extending therefrom comprise a"pillow.' It is to be
understood,
however, that some pillows may not have the cantilever portion.
Each of the first and second pluralities of micro-regions can be
substantially continuous, substantially semi-continuous, be formed by a
plurality
of discrete protuberances, or comprise a combination thereof. If the first
plurality
of micro-regions comprises a substantially continuous and macroscopically
monoplanar network area, the second plurality of micro-regions can comprise a
plurality of discrete pillows dispersed throughout the network area, at leaSt
some
of the pillows comprising the fibrous dome extending from the network area and
the fibrous cantilever portion laterally extending from the dome.
Some of the fibrous cantilever portions are elevated from the first plane to
form pockets comprising substantially void spaces between the first plane and
the.fibrous cantilever portion. These pockets are believed to provide
additional
room for receiving liquids during the use of the fibrous structure and thus
enhance its absorptive properties. The fibrous cantilever portions of the
fibrous
structure also increase Its overall surface area, thereby further contributing
to
increasing the absorptive properties of the fibrous structure. In a cross-
section
perpendicular to the X-Y plane, a ratio of an overall cross-sectional
perimeter of
at least one of the pillows comprising the fibrous cantilever portion to a
cross-
sectional
base of said pillow is 4/1 or greater.
13
CA 02588743 2007-05-29
Some of the pillows, whether they comprise a continuous pattern, a semi-
continuous pattem, or a pattern of discrete protuberances, may not have a well-
defined fibrous cantilever portion in a cross-section perpendicular to the X-Y
plane. But even without the fibrous cantilever portions, the fibrous structure
of the
present invention provides the benefit of an increased surface area of the
second
plurality of micro-regions. Therefore, in another aspect, the fibrous
structure of
the present invention comprises a first pluraiity of micro-regions defining a
first
plane and having a first elevation and a second plurality of micro-regions
outwardly extending from the first plane to form a second elevation, wherein
In at
io least one cross-section perpendicular to the first plane the second
plurality of
micro-regions comprises a pillow having a cross-sectional perimeter and a
cross-
sectionai base measured at the first elevation, wherein a ratio of the cross-
sectional perimeter to the cross-sectional base is 4/1 or greater.
The differential regions of the fibrous structure may have differential basis
weights and/or differentiai densities, and/or differential fiber compositions.
In one
embodiment, a density of the first plurality of micro-regions is greater than
a
density of the second plurality of micro-regions. In another embodiment, a
basis
weight of the second plurality of micro-regions is greater than a basis weight
of
the first plurality of micro-regions. In still another embodiment, a ratio of
the
2o amount of long fibers relative to the amount of short fibers can be varied
such
that that ratio is 1.0, greater than 1.0, or less than 1Ø The fibrous
stnacture of
the present invention can have an intermediate density relative to the high
density of the first pturaliiy of micro-regions and the low density of the
second
plurality of micro-regions. The fibrous cantilever portions may have such an
intermediate density.
A laminated structure of the present invention comprises at least two
laminae. A least one of the laminae comprises the fibrous structure described
above. In one embodiment, the laminated fibrous structure of the present
invention comprises at least a first lamina and a second lamina jained
together.
3o The first lamina comprises a fibrous sheet having at least two regions and
14
CA 02588743 2007-05-29
comprising a first plurality of micro-regions defining a first plane and
having a first
elevation, and a second pluraiity of micro-regions comprising a plurality of
fibrous
domes,outwardly extending from the first plane to define a second elevation
and
a plurality of fibrous cantilever portions laterally extending from the domes
at the
second elevation. The other lamina or laminae in the laminated structure may
or
may not have fibrous cantilever portions. Of course, the other lamina or
laminae
may be made by any process known in the art, including, without limitation,
through-air-drying and conventional processes. The laminae can be joined such
that the fibrous cantilever portions of one lamina face the other lamina.
lo Alternatively, the Iaminae having the fibrous cantilever portions can be
joined by
a side opposite to that having the fibrous cantilever portions.
In the laminated fibrous structure comprising at least two laminae, each
laminae can have the fibrous cantilever portions spaced from the first plane
to
form pockets comprising substantially void spaces between the first plane and
the fibrous cantilever portions. Then, if the two laminae are joined together
such
that the fibrous cantilever portions of one lamina face the fibrous cantilever
portions of the other lamina, at least some of the fibrous cantilever portions
of
one lamina can be disposed in the pockets formed between the fibrous
cantilever
portions and the first plane of the other lamina. Such a joining of two
laminae is
2o believed to provide a limited movability of the laminae relative to one
another in
at least one lateral direction, without tearing of either lamina or separation
of the
laminae. Such a movability is believed to facilitate softness and absorbency
of
the laminated fibrous structure of the present invention. Aiternatively, the
laminae can be joined such that their respective fibrous cantilever portions
face
opposite directions.
A process for making a fibrous structure of the present invention
comprises the following steps:
providing the deflection member of the present invention, described above;
providing a plurality of fibers and depositing the plurality of fibers on the
so def(ection member;
CA 02588743 2007-05-29
deflecting a portion of the plurality of fibers into the deflection conduits
of the
deflection member such as to cause some of the deflected fibers or portions
thereof to be disposed within the void spaces formed between the X-Y plane and
the suspended portions of the deflection member, thereby forming a partly-
formed fibrous structure; and
separating the partly-formed fibrous structure from the deflection member,
thereby forming the fibrous structure of the present invention.
The process can further comprise a step of pressing the deflection
member having the partly-formed fibrous structure thereon against a pressing
1o surface, such as, for example, a surface of a Yankee drying drum, thereby
densifying portions of the partly-formed fibrous structure.
The step of deflecting a portion of the plurality of fibers may comprise
applying a mechanical pressure to the portion of the fibers, or a fluid
pressure
differential, such as, for example, a vacuum pressure, to the plurality of
fibers. In
one embodiment, a web disposed on the deflection member can be overlaid with
a flexible sheet of material such that the web is disposed between the
flexible
sheet of material and the deflection member. The flexible sheet of material
has
an air permeability less than that of the deflection member. The flexible
sheet of
material can also be air-impermeable. An application of a fluid pressure
2o differential to the sheet of material causes deflection of at least a
portion of 'the
sheet of material towards the papermaking belt and deflection of at least a
portion of the web into the conduits of the papermaking beit.
The plurality of fibers can be selected from any fibers known in the art, for
example, cellulosic fibers, synthetic fibers, or any combination thereof. The
plurality of fibers can also be supplied in the form of a moistened fibrous
web in
which portions of the web could be effectively deflected into the deflection
conduits and the void spaces formed between the suspended portions and the X-
Y plane of the deflection member.
16
CA 02588743 2007-05-29
The present invention also provides a mask for use in a process for curing
a curable material, such as, for example, a photosensitive resinous material,
suitable for making the deflection member of the present invention. In one
embodiment, the mask of the present invention comprises a structure having a
top side and a bottom side opposite to the top side, and a pattern of
transparent
regions and opaque regions, wherein the opaque regions comprise at least first
opaque regions having a first opacity and second opaque regions having a
second opacity different from the first opacity.
The transparent regions and the opaque regions can comprise a non-
1 o random and repeating pattern. The opaque regions can comprise a
substantially
continuous pattem, a substantially semi-continuous pattem, a pattern formed by
a plurality of discrete areas, or any combination thereof. Furthermore, the
first
opaque regions and the second opaque regions can comprise a non-random and
repeating pattern. The first opaque regions, the second opaque regions, or
both
of the first and second opaque regions can comprise a substantially continuous
pattern, a substantially semi-continuous pattern, a pattem formed by a
plurality of
discrete areas, or any combination thereof. The second opaque regions can be
adjacent to or separated from the first opaque regions.
The opaque regions can comprise more than two differential opacities.
2o For example, the mask according to the present invention can comprise third
opaque regions having a third opacity intermediate the first opacity and the
second opacity.
In one embodiment, the opaque regions comprise a gradient opacity that
gradually changes in at least one direction. The region of gradient opacity
may
comprise the first opaque region, the second opaque region, or be separate
from
those. The gradient opacity can change, in equal increments or altematively in
unequal increments, in one or several directions.
In another embodiment, the mask comprises a three-dimensional
topography, such as, for example, a pattem of protrusions extending from at
so least one side of the mask. Protrusions extending from the bottom side of
the
1 17
CA 02588743 2007-05-29
mask can be structured and configured to be imprinted into the coating of a
curable material to form corresponding depressions, or voids, in the coating.
Protrusions extending from the top side of the mask can be structured and
configured to provide voids into which the liquid curable material can flow to
approximate the contours of the mask's topography. Either one or both of the
patterns of protrusions can comprise a substantially continuous pattem, a
substantially semi-continuous pattem, a pattem formed by a plurality of
discrete
protuberances, or any combination thereof. Either one or both of the patterns
of
protrusions can correlate with the pattern of transparent regions and opaque
1o regions to form a combined non-random and repeating pattern. In one such
embodiment, the opaque regions comprise distal surfaces of the protrusions.
In one embodiment of the mask, the pattem of transparent and opaque
regions is independent and separable from the pattem of the protrusions. Such
a mask can comprise a composite structure formed by at least a first element
and a second element juxtaposed therewith in a face-to-face relationship,
wherein the first element forms the pattern of transparent and opaque regions,
and the second element forms the pattern of protrusions. The first and second
elements in such a composite mask can be superimposed to form a combined
non-random and repeating pattem of the opaque regions and the protrusions.
The mask having differential opacities can be used in a process for curing
a curable material for constructing the deflection member of the present
invention. For example, when the mask comprising the first and second
opacities is positioned between the source of curing radiation and a coating
of
the curable material, to selectively shield the coating from the curing
radiation,
2s the first opaque regions having a first opacity shield first areas of the
coating from
the curing radiation to cause the first regions to remain uncured through the
entire thickness of the coating, the second opaque regions having the second
opacity partially shield second areas of the coating to allow the curing
radiation to
cure the coating through a partial thickness less than the entire thickness of
the
3o coating, and the transparent regions leave third areas of the coating
unshielded
18
CA 02588743 2007-05-29
to allow the curing radiafion to cure the curable material through its entire
thickness.
If the mask having gradient opacity is used for curing a coating, a region
having the gradient opacity shields a corresponding area of the coating from
the
curing radiation such as to cause said corresponding area to cure through a
gradually changing thickness correlating with the gradually changing opacity
of
the mask's gradually-opaque region. For example, if the gradient opacity
changes (increases or decreases) in equal increments or decrements in one
direction, a depth of curing of the corresponding area of the coating will
also
1o change gradually in equal decrements or increments. Of course, the gradient
opacity may change in unequal increments.
The mask of the present invention can be made by a process comprising
the steps of providing a thin transparent material of substantially uniform
thickness, such as, for example, a transparent film; forming a pattern of
opaque
regions on the material according to a first predetermined pattern; and
embossing the material according to a second predetermined pattern. The
process can be structured such that the first predetermined pattern
substantially
correlates with the second predetermined pattem to form a combined non-
random repeating pattern. For example, the steps of forming the opaque regions
2o and embossing the material can be performed simultaneously. The step of
forming a pattem of opaque regions can comprise applying ink to selected
regions of the thin transparent material. The selected regions can comprise
distal surfaces of the embossed areas of the material.
The mask having regions of differential opacities can be formed in a multi-
step process comprising printing a transparent film to form a pattern of
opaque
regions having a certain initial opacity, and then printing the film a second
(third,
fourth, etc.) time, as needed, to form a pattem (or pattems) of opaque regions
having another opacity (or other opacities), different from the initial
opacity (or
different from one another). The differential opacities can also be formed in
one-
so step printirlg, for example, by a Gravure roll comprising a pattem having a
19
CA 02588743 2007-05-29
differential depths for receiving ink. During printing, the ink transferred
from the
Gravure roll to the transparent film will have regions of differential
intensities,
reflecting the differentiai depths of the roll's pattern. Other methods of
forming
opaque regions can be used in the present invention, including, without
limitation,
chemical, electromagnetic, laser, heat, etc.
In another aspect, a process for making the deflection member of the
present invention, using a three-dimensional mask described above, comprises
the following steps:
providing a coating of a liquid curable material supported by a forming
surface,
io the coating -having a bottom surface facing the forming surface, a top
surface
opposite to the bottom surface, and a first thickness defined between the top
and
bottom surfaces;
providing a source of curing radiation structured and configured to emit a
curing
radiation to cure the coating supported by the forming surface;
providing a mask having a first pattern of transparent regions and opaque
regions therein, and a second pattem of protrusions outwardly extending from
one side of the mask;
positioning the mask between the coating and the source of curing radiation
such
that the second pattern of protrusions is at least partially submerged into
the
coating, thereby forming three-dimensional voids therein;
curing the curable material, wherein the opaque regions of the first pattern
at
least partially shield selected areas of the coating from the curing radiation
such
that the selected areas are cured through at least a portion of the first
thickness,
thereby forming a partly-formed defiection member; and
removing substantially all uncured material from the partly-formed deflection
member to leave a hardened resinous structure which forms the deflection
member comprising a macroscopicaiiy monoplanar, pattemed framework having
a web-side formed from the top surface of the coating, and a backside formed
from the bottom surface of the coating.
CA 02588743 2007-05-29
As explained above, the first pattern, the second pattern, or both the first
and second pattems can be non-random and repeating. Depending on a specific
embodiment of the mask, the mask can be positioned such that the second
pattern of protrusions is submerged into the selected areas that are at least
partially shielded by the opaque regions of the first pattern of the mask.
Alternatively or additionally, the mask can be positioned such that that the
second pattem of protrusions is submerged into the areas that are not shielded
by the opaque regions of the first pattem of the mask.
In one embodiment, the mask comprises a composite structure formed by
1o at least a film and an,embossing element juxtaposed therewith, the
embossing
element forming the second pattem of protrusions. In such an embodiment, the
embossing element, the film, or both the embossing element and the film can
comprise opaque regions. If both the embossing element and the film comprise
opaque regions, it may be beneficial to provide that the opaque regions of the
embossing element and the opaque regions of the film are mutually coordinated
to form the first pattem of transparent and opaque regions.
The embossing element can be transparent to the curing radiation.
Alternatively, the embossing element can be impermeable to the curing
radiation.
In one embodiment, the embossing element has voids therethrough. Such an
embossing element can comprise, for example, and without limitation, a woven
element having open areas therethrough, or a mesh wire.
A process for making a deflection member, using the composite mask can
comprise the following steps:
providing a coating of a liquid curable rnaterial supported by a forming
surface,
the coating having a bottom surface facing the forming surface, a top surface
opposite to the bottom surface, and a first thickness defined between the top
and
bottom surfaces;
21
CA 02588743 2007-05-29
providing a source of curing radiation structured and configured to emit a
curing
radiation to cure the coating of the liquid curable material supported by the
forming surface;
providing an embossing element and juxtaposing the embossing element with
the top surface of the coating such that the embossing element is at least
partially submerged into the coating, thereby forming a pattern of voids in
the
coating;
providing a film and juxtaposing the film with the embossing element, wherein
the
embossing element and the film in combination comprise a pattem of transparent
lo regions and opaque regions, wherein the opaque regions shield areas of the
coating from the curing radiation, while the transparent regions cause other
areas
of the coating to be unshielded;
curing the unshielded areas of the coating by exposing the coating to the
curing
radiation through the embossing element and the film, while leaving the
shielded
areas of the coating uncured, thereby forming a partly-formed deflection
member; and
removing substantially all uncured material from the partly-formed deflection
member to leave a hardened resinous structure comprising a macroscopically
monoplanar, patterned framework having a web-side formed from the top surface
of the coating, and a backside formed from the bottom surface of the coating.
In its industrial application, each of the processes of making the deflection
member, described herein, can comprise a continuous process. For example,
the continuous process of making the deflection member, using the three-
dimensional mask, comprises the following steps:
providing a coating of a liquid curable material supported by a forming
surface,
and continuousiy moving the forming surface with the coating in a machine
direction, the coating having a bottom surface facing the forming surface, a
top
surface opposite to the bottom surface, and a first thickness defined between
the
top and bottom surfaces;
22
CA 02588743 2007-05-29
providing a souroe of curing radiation structured and configured to emit a
curing
radiation to continuously cure the coating supported by the forming surface
moving in the machine direction;
continuously providing a transparent film;
continuously printing the film to form a first pattern of opaque regions
therein;
continuously embossing the film to form a second pattern of protrusions
therein;
continuously moving the film having the first pattern of opaque regions and
the
second pattern of protrusions to position said film between the coating and
the
source of curing radiation such that the second pattern of protrusions is at
least
io partially submerged into the coating, thereby forming three-dimensional
voids
therein;
continuously cur+ng the curable material, wherein the opaque regions of the
first
pattern at least partially shield selected areas of the curable material from
the
curing radiation such that the selected areas are cured through at least a
portion
is of the first thickness of the coating, thereby forming a partly-formed
deflection
member; and
continuously removing substantially all uncured material from the partly-
formed
deflection member to leave a hardened resinous structure comprising a
macroscopically monoplanar, patterned framework having a web-side formed
20 from the top surface of the coating, and a backside formed from the bottom
surface of the coating.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic plan view of an embodiment of a defiection member of
the present invention, comprising a framework formed by a first layer
26 and a second layer joined together in a face-to-face relationship, each
of the first and second layers comprising a continuous network and a
plurality of discrete deflection conduits dispersed therethrough.
23
CA 02588743 2007-05-29
FIG. 2 is a schematic instantaneous cross-secctional view of the deflection
member shown in FIG. 1, taken along lines 2-2 of FIG. 1, and also
showing a fibrous web of the present invention disposed on the
deflection member.
FIG. 3 is a schematic plan view of another embodiment of the deflection
member of the present invention, comprising a framework formed by a
first layer and a second layer joined together in a face-to-face
relationship, wherein the first layer comprises a continuous network
and a second layer comprises a semi-continuous network.
to FIG. 4 is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 3, taken along lines 4-4 of FIG. 3.
FIG. 5 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
wherein the first layer comprises a continuous network and a second
layer comprises a plurality of discrete protuberances.
FIG. 6 is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 5, taken along lines 6-6 of FIG. 5.
FIG. 7 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
wherein the first layer comprises a serni-continuous network and a
second layer comprises a continuous network.
FIG. 8 is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 7, taken along lines 8-8 of FIG. 7.
FIG. 9 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
24
CA 02588743 2007-05-29
wherein each of the first and second layers comprises a semi-
continuous network.
FIG. 10 is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 9, taken along lines 10-10 of FIG. 9.
FIG. 10A is a schematic cross-sectional view of the deflection member shown in
FIG. 9, taken along lines 10A-10A of FIG. 9.
FIG. 11 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
wherein the first layer comprises a semi-continuous network and a
second layer comprises a plurality of discrete protuberances.
FIG. 12 is a schematic Instantaneous cross-sectional view of the deflection
member shown in FIG. 11, taken along lines 12-12 of FIG. 11.
FIG. 12A is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 11, taken along lines 12A-12A of FIG. 11.
FIG. 13 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
wherein the first layer comprises a plurality of discrete protuberances
and a second layer comprises a continuous network.
FIG. 14 is a schematic Instantaneous cross-sectional view of the deflection
member shown in FIG. 13, taken along lines 14-14 of FIG. 13.
FIG. 15 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
wherein the first layer comprises a plurality of discrete protuberances
and a second layer comprises a semi-continuous network.
CA 02588743 2007-05-29
FIG. 16 is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 15, taken along lines 16-16 of FIG. 15.
FIG. 17 is a schematic plan view of an embodiment of the deflection member
of the present invention, comprising a framework formed by a first layer
and a second layer joined together in a face-to-face relationship,
wherein each of the first and second layers comprises a plurality of
discrete protuberances.
FIG. 18 is a schematic instantaneous cross-sectional view of the deflection
member shown in FIG. 17, taken along lines 18-18 of FIG. 17.
y o FIG. 19 Is a schematic side-elevational view of an embodiment of a process
for
making the deflection member according to the present invention.
FIG. 20 is a schematic plan view of a fragment of the embodiment of the
process of making the deflection member according to the present
Invention, showing a mask having transparent and opaque regions, the
mask being disposed on the top of a coating of the curable material.
FIG. 21 is a schematic cross-sectional view of the embodiment of the process
for making the deflection member, schematically showing selective
curing of the coating of the curable material through the mask shown in
FIG. 20, and taken along lines 21-21 of FIG. 20.
2o FiGs. 22A-22C are schematic and partial plan views of embodiments of the
process for making the deflection member according to the present
invention, each showing an exemplary embodiment of the mask having
transparent and opaque regions.
FIG. 23 is a schematic instantaneous cross-sectional view of an embodiment of
the process of making the deflection member shown in FIG. 22A and
taken along lines 23-23 of FIG. 22A, schematically showing selective
curing of a coating of a curable material.
FIG. 24 is a schematic instantaneous cross-sectional view similar to that
shown
in FIG. 23, and taken along the line 24-24 of FIG. 22B.
26
CA 02588743 2007-05-29
FIG. 25 is a schematic instantaneous cross-sectional view similar to that
shown
in FIGs. 22 and 24, and taken along the line 25-25 of FIG. 22C.
FIG. 25A is a schematic instantaneous cross-sectional view similar to that
shown
in FIG. 24, showing an embodiment of a three-dimensional pattern of
the mask.
FIG. 26 is a schematic plan view of a fibrous structure of the present
invention,
comprising a substantially continuous and macroscopically monoplanar
network area and a plurality of discrete pillows dispersed therethrough.
FIG. 27 is a schematic instantaneous cross-sectional view of the fibrous web
shown in FIG. 26 and taken along lines 2.7-27.
FIG. 28 is a schematic plan view of the fibrous structure of the present
Invention, comprising a semi-continuous pattems of network area and
pillows.
FIG. 29 is a schematic instantaneous cross-sectional view of the fibrous web
shown in FIG. 28 and taken along lines 29-29.
FIG. 30 is a schematic instantaneous cross-sectional view of a portion of the
fibrous structure of the present invention, showing in more detail a
pillow having a fibrous cantilever portion.
FIG. 31 is another schematic instantaneous cross-sectional view of the fibrous
structure, similar to that shown in FIG. 30.
FIGs. 32-41 are photomicrographs showing, in cross-section, examples of the
fibrous structure of the present invention.
FIG. 42 is a schematic side-elevational view of the process of making a
fibrous
structure according to one embodiment of the present invention.
FIG. 43 is a schematic cross-sectional view of an embodiment of a laminated
fibrous structure of the present invention, comprising two iaminae
joined together.
27
CA 02588743 2007-05-29
FIG. 44 is a schematic cross-sectionai view of another embodiment of the
laminated fibrous structure of the present invention comprising two
laminae joined together.
FIGs. 45 and 46 are photomicrographs showing examples of cross-sectional
configurations of the fibrous structure of the prior art.
FIG. 47 is a schematic cross-sectional view of the pillow of the prior art
fibrous
structure shown in FIG, 46.
FIGs. 48 and 49 schematicafiy show, in instantaneous cross-sectional view,
another embodiment of the muiti-iayer deflection member of the
present invention, comprising a first layer and a second layer, the first
layer having a defonnabiiity greater than the deformability of the first
layer. tn FIG. 48 the deflection member is shown free of a
compressive force, and in FIG. 49 the deflection member is shown
under application of the compressive force.
FIG. 50 is a schematic side-elevational view of an embodiment of the process
for making the deflection member according to the present invention,
showing a process of forming a mask having protrusions.
FIG. 51 is a schematic side-elevational view of an embodiment of the process
for making the deflection member of the present invention, using a
three-dimensional embossing element.
FIG. 52 is a schematic side-elevational view of an embodiment of the process
for making the deflection member of the present invention, wherein the
mask comprises a composite structure.
FIG. 52A is a partial plan view of an embossing element taken in the direction
of
the arrow A of FIG. 52.
FIG. 53 is a schematic instantaneous side-elevational view of an embodiment
of the deflection member of the present invention, having fluid-
impermeable deflection conduits.
28
CA 02588743 2007-05-29
FIG. 54 is a schematic instantaneous cross-sectional view of one embodiment
of the process of the present invention, wherein fibers are disposed
between the deflection member of the present invention and a flexible
sheet of material.
DETAILED DESCRIPTION OF THE INVENTION
Deflection Member
As shown in FIGs. 1-18, a deflection member 10 of the present invention
comprises a macroscopically monoplanar, patterned framework 20. The
pattemed framework 20 may be made from a variety of materials, including but
io not limited to: resinous material, metal, metal-impregnated resin, plastic,
or any
combination thereof. However, as used herein, the term "framework' does not
include a structure that . is formed by mutually perpendicular interwoven
filaments, such as, for example, a forming wire or a similarly formed
structure.
Such a structure, comprising a plurality of mutually perpendicular filaments,
may
be used as a reinforcing element in the deflection member 10 of the present
invention, as will be discussed below, but does not constitute the "framework"
of
the deflection member 10.
If the framework 20 of the deflection member 10 is made of the resinous
material or other material having insufficient inherent strength, or has a
pattern
that can be distorted when pulled in a machine direction (defined below), a
reinforcing element 50 is typically used to enforce the framework 20 of the
deflection member 10. The reinforcing element 50 may be necessary when the
patterned framework 20 comprises a semi-continuous pattern or a pattern
comprising a plurality of discrete protuberances, as will be discussed in
greater
detail below. The reinforcing element 50 is positioned between the web-side 21
and at least a portion of the backside 22 of the framework 20. While the
reinforcing element 50 is generally parallel to the backside 22 of the
framework,
a portion of the reinforcing element 50 may extend beyond the backside 22 of
the framework 20, thereby creating surface irregularities in the backside 22
of
29
CA 02588743 2007-05-29
the framework 20, as discussed in more detail below. In some embodiments,
the reinforcing element 50 may comprise the backside 22 of the framework 20.
The patterned framework 20 can be joined to the reinforcing element 50.
The reinforcing element 50 has an upper side 51 and a lower side 52 opposite
to
the upper side 51. The web-side 21 of the framework 20 and the upper side 51
of the reinforcing element 50 faoe one direction, and the backside 22 of the
framework 20 and the lower side 52 of the reinforcing element 50 face the
opposite direction. As defined herein, the backside 22 of the framework forms
an
X-Y plane. Since the reinforcing element 50 is most typically adjacent to the
1o backside 22 of the framework 20 (FIGs. 2, 4, 6, 8, 10, 12, 14, 16, and 18),
it
could also be said that in some embodiments the reinforcing element 50, as a
whole, defines the X-Y plane. One skilled in the art will appreciate that the
symbols "X," "Y," and "Z" designate a system of Cartesian coordinates, wherein
mutually perpendicular "XA and "Y" define a reference plane formed by the
backside 22 of the framework 20 (or by the reinforcing element 50) when the
deflection member 10 is disposed on a flat surface, and "Z" defines an
orthogonal to the X-Y plane. As used herein, the term "Z-direction" designates
any direction perpendicular to the X-Y plane. Analogously, the term "Z-
dimension" means a dimension, distance, or parameter measured parallel to the
Z-direction. It should be carefully noted, however, that an element that
"extends"
in the Z-direction does not need itself to be oriented strictty parailel to
the Z-
direction; the term "extends in the Z-direction" in this context merely
Indicates
that the element extends in a direction which is not parallel to the X-Y
plane.
Analogously, an element that "extends in a direction parallel to the X-Y
plane"
2s does not need, as a whole, to be parallel to the X-Y plane; such an element
can
be oriented in the direction that is not parallel to the Z-direction.
One skilled in the art will also appreciate that the reinforcing element 50,
as well as the deflection member 10 as a whole, does not need to (and indeed
cannot in some embodiments) have a planar configuration throughout its length,
especially when used in a typical industrial process for making a fibrous
structure
500 of the present invention, as the deflection member 10 in the form of an
30
CA 02588743 2007-05-29
endless belt travels through the equipment in a direction indicated by a
directional arrow "B" (FIG. 42). Also, and the concept of the deflection
member
being disposed on a flat surface and having the macroscopical "X-Y" plane is
conventionally used herein for the purpose of describing relative geometry of
5 several elements of the generally flexible deflection member 10. A person
skilled
in the art will appreciate that when the deflection member 10 curves or
otherwise
deplanes, the X-Y plane follows the configuration of the deflection member 10.
As used herein, the terms containing "macroscopical" or "macroscopically"
refer to an overall geometry of a structure under consideration when it is
placed
io in a two-dimensional configuration. In contrast, "microscopical" or
"microscopically" refer to relatively small details of the structure under
consideration, without regard to its overall geometry. For example, in the
context
of the deflection member 10, the term "macroscopicaily planar" means that the
deflection member 10, when it is placed in a two-dimensional configuration,
has -
is as a whole -- only minor and tolerable deviations from the absolute
planarity,
which deviations do not adversely affect the deflection member's performance.
At the same time, the patterned framework 20 of the deflection member 10 can
have a microscopical three-dimensional pattern of deflection conduits and
suspended portions, as will be described below.
The framework 20 comprises a plurality of bases 30 and a piurality of
suspended portions 49. The plurality of bases 30 extends in the Z-direction.
If
the deflection member 10 comprises the reinforcing element 50, the plurality
of
bases 30 is joined to the reinforcing element 50 and extends therefrom
outwardly. The suspended portions 49 laterally extend from the plurality of
bases
30. The plurality of suspended portions 49 typically extend in at least one
direction parallel to the X-Y plane. Since there is a virtually Infinite
number of
directions parallel to the X-Y ptane, orientations of the suspended portions
49
may be chosen based on a desired design of the end product, that can be
dictated by a particular method of making the deflection member 10 or a method
3o of making a fibrous structure, or both, as described below.
31
CA 02588743 2007-05-29
The pluraiity of bases 30 form spaces therebetween. The spaces
between the bases 30 form so-called "deflection conduits." The deflection
conduits can extend In the Z-direction from the web-side 21 toward the
backside
22 of the framework 20 and provide spaces into which a plurality of fibers can
be
deflected during a papermaking process of the present invention, to form so-
called fibrous "pillows" 540 of the fibrous structure 500 (FIGs. 27-41). In
the ftuid-
permeable deflection member 10, the conduits extend from the web side 21 to
the backside 22 through the entire thickness of the framework 20. The fibrous
pillows 540 can have a density that is lower than the density of the rest of
the
io fibrous structure 500, thus faciiitating absorbency and softness of the
fibrous
structure 500, as a whole. The pillows 540 can have a basis weight that is
greater than that of the rest of the fibrous structure 500. The pillows 540
also
contribute to increasing an overall surface area of the fibrous structure 500,
thereby further encouraging the absorbency and softness thereof.
As used herein, by the requirement that the suspended portions 49 extend
from the plurality of bases 30 in at least one direction, it is meant that
each of the
suspended portions 49, when viewed in the cross-section perpendicular to the X-
Y plane, lateralfy extends in a direction that is not parallel to the Z-
direction and
that can be substantially paraiiei to the X-Y plane. As used herein, by the
2o requirement that the suspended portions 49 be elevated from the X-Y plane,
it is
meant that there is a free space, or gap, in the Z-direction between the
suspended portions 49, or at least a part thereof, and the X-Y plane. That is,
the
suspended porbons 49 are "suspended" because they are elevated from the X-Y
plane or the reinforcing element 50, and a gap, or void, exists between the
suspended portion and the X-Y plane. It should be noted, however, that the
suspended portion 49 need not form the gap throughout the entire length of the
suspended portion 49. That is, the suspended portion 49 can, at some point of
its length, touch the reinforcing element 50, due to, for example, deplaning
or
deformation of the deflection member 10 or the suspended portion 49, as long
as
3o the suspended portion 49 itself is not directly joined to the reinforcing
element 50.
Also, these gaps between the suspended portions 49 and the X-Y plane can
32
CA 02588743 2007-05-29
differentiate in their respective shapes and dimensions, including Z-
dimensions, i.
e., they do not need to be the same for all or some of the suspended portions
49.
For example, a distance between one suspended portion 49 and the reinforcing
element 50 may be different from a distance between another suspended portion
49 and the reinforcing element 50 (FIG. 25). Also, the distances between the X-
Y plane and the different suspended portions may gradually change or be
irregular (FIGs. 23-24).
The suspended portions 49 may be either integral with or securely joined
to the bases 30. As used herein, the "integralA suspended portions are those
io suspended portions 49 that have been formed together with formation of the
bases 30, in the course of one embodiment of the process of making the
deflection member 10 of the present invention, as will be de$cribed below in
detail (FIGs. 22A-25A). The "joined" suspended portions are those that have
been made separately from the bases 30 and then securely joined to the bases
30. An example of the joined suspended portions 49 is also described below, in
the context of an embodiment of the deflection member 10 comprising a multi-
layer structure, and more specifically an exemplary two-layer deflection
member
10, and a process of making the same (FIGs. 1-19). ln such an embodiment,
one of the joined layers comprising the deflection member 10 forms the
plurality
2o of bases 30, while the other layer forms the suspended portions 49. For
convenience, the layer comprising the plurality of bases 30 is also designated
herein by the reference numeral 30.
When viewed in a cross-section perpendicular to the X-Y plane, the
deflection member 10 of the present invention can comprise two types of the
suspended portions 49 -- based on their relation to the bases: bridgingu
suspended portions and "cantilever" suspended portions. The both "bridging"
and "cantilever" terms are used herein conventionally and intended to be
descriptive in that the bridging suspended portion is the suspended portion 49
which spans, or "bridges," a distance between at least two bases, thereby
interconnecting the at least two bases. The bridging suspended portions are
33
CA 02588743 2007-05-29
shown, for example, in FIGs. 9, 10A, 15, 24, 25, and 25A. Most typically, but
not
necessarily, these two interconnected bases are adjacent bases. Embodiments
are contemplated, however, wherein the interconnected bases are not mutually
adjacent, but are separated by another base or other bases. (See, for example,
FIG. 15, the first from the right "sindsoidalp second-layer element.) Another
embodiment wherein the bridging suspended portion interconnects two non-
adjacent bases is the framework 20 in which the bases have differential
heights
so that at least some of the bases having relatively smaller height do not
reach
the suspended portions (not shown). Such relatively short bases can be
lo positioned intermediate relatively high bases that are interconnected by
the
bridging suspended portions.
The cantilever suspended portion is the suspended portion 49 which
laterally extends from one of the bases 30 but does not reach an adjacent base
30, when viewed in a particuiar cross-section. The cantilever suspended
portions
are shown, for example, in FIGs. 12 and 23.
It should be appreciated that in some instances, the same suspended
portion 49 may appear as "bridging" as viewed in one cross-section, and
"cantilever" as viewed in another cross-section. For example, in a cross-
sectional view of FIG. 10, some of the suspended portions 49 (formed by. a
second semi-continuous layer 40, as will be discussed below in sufficient
detail)
appear to form "cantilever" portions, while other suspended portions 49 appear
to
be unsupported at all. At the same time, in the cross-sectional view of FIG.
10A,
taken along one of the linear semi-continuous elements of the second layer 40,
the suspended portion 49 appears as a "bridging" portion, because it spans, or
bridges, at least two adjacent bases (formed by a first layer 30, as will be
discussed below).
Each of the suspended portions 49 has a web-oriented surface 49a and a
back surface 49b (FiGs. 10 and f 0A). As used herein, the term "web-orlented
surface" designates that surface of the suspended portion 49 which forms the
web-side 21 of the framework 20. When the web is disposed on the deflection
34
CA 02588743 2007-05-29
member 10, the web-oriented surface 49a is adjacent to the web. In the
embodiment in which the deflection member 10 comprises the reinforcing
element 50, the web-oriented surface 49a faces away from the reinforcing
element 50. Typically, but not necessarily, the web-oriented surface 49a is
parallel to the X-Y plane. The back surface 49b designates a surface of the
suspended portion 49, which is opposite to the web-orierited surface 49a. In
the
embodiment in which the deflection member 10 comprises the reinforcing
element 50, the back surface 49b faces the reinforcing element 50, and
specifically, its upper side 51.
FIGs. 2, 4, 6, 8, 10, 10A, 12, 14, 16, 18, 23-25, 25A, 48, and 49 show, in
cross-section, various embodiments of the suspended portion 49. With
reference to FIGs. 23-25, the reference numeral "49" (without regard to a
parenthetical suffix) ts used herein to generically designate any suspended
portion regardless of its specific embodiment. Analogously, the reference
numerals "49a" and "49b" (without regard to a parenthetical suffix)
generically
designate the web-oriented surface and the back surface, respectively, of the
suspended portion 49, regardless of these surfaces' specific embodiments.
Each of the parenthetical suffixes "(1)," "(2)," "(3)," etc. designates an
exemplary
embodiment of the suspended portion 49 and its corresponding web-oriented
surface 49a and back surfaces 49b, as will be explained in sufficient detail
below.
The back surface 49b may be substantially parallel to the X-Y plane
and/or parallel to the web-oriented surface 49a, as best shown in FIGs. 2, 4,
6, 8,
10, 12, 14, 16, 18, and 25. FiGs. 23 and 24 show embodiments in which the
back surfaces 49b of some of the suspended portions 49 are not parallel to the
web-orlented surfaces 49a and are not parallel to the X-Y plane. In FIG. 23,
for
example, the suspended portion 49(2), 49(3), and 49(4) has the back surface
49b(2), 49b(3), and 49b(4), respectively, which are "angled" relative to the X-
Y
plane. Moreover, the back surface 49b does not need to be linear or flat. For
example, in FIGs. 23 and 24, the suspended portions 49(1) and 49(5),
3o respectively, have essentially linear or flat back surfaces 49b(1), and
49b(5),
CA 02588743 2007-05-29
respectiveiy, while the suspended portions 49(3) and 49(4) (FIG. 23), and
49(6)
and 49(7) (FIG. 24) have curved (concave or convex) back surfaces 49b(3) and
49b(4) (FIG. 23), and 49b(6) and 49b(7) (FIG. 24), respectively.
It should be understood that the foregoing embodiments of the suspended
portion 49 and its back surface 49b are mere examples used for the purposes of
illustrating the present invention,-but not for.the purposes of limiting the
invention.
There could be virtually an unlimited number of possible combinations,
variations, and mutual orientations of the suspended portion 49 and its web-
oriented and back surfaces 49a and 49b, including circular, curved, and
irregular
lo shapes, ali of which are contemplated by the present invention. They all
couid
be designed and shaped using the novel process of making the deflection
member 10 of the present invention, as described below.
In several exemplary embodiments shown in FIGs. 1-18, the framework 20
of the deflection member 10 comprises a multi-layer composite structure formed
by at least a first layer 30 and a second layer 40 joined to the first layer
30 in a
face-to-face reiationship therewith. By the requirement that the framework 20
comprise "at least" two layers it is meant that the framework 20 according to
the
present invention may comprise more than two layers -- for example, three,
four,
five, etc. layers (not shown), as one skilled in the art should readily
understand.
2o Each of the first and second layers 30, 40, has a top surface and a bottom
surface opposite to the top surface. As shown, for example, In FIGs. 4, 6, 8,
10,
the first layer 30 has a top surface 31 and a bottom surface 32 opposite to
the
top surface 31. Analogously, the second layer 40 has a top surface 41 and a
bottom surface 42 opposite to the top surface 41. In the formed framework 20,
the top surface 31 of the first layer 30 contacts the bottom surface 42 of the
second layer 40. A top surface 41 of the second layer 40 comprises the web-
side 21 of the framework 20, and the bottom surface 32 of the first layer 30
comprises the backside 22 of the framework 20. One skilled in the art will
appreciate that the terms "top" and "bottom" are descriptive only to the
extent the
3o deflection member 10 is shown herein in several cross-sectional views. Of
36
CA 02588743 2007-05-29
course, during a manufacturing process, the deflection member 10 can be
positioned such that the "bottom" surface is above the "top" surface.
Each of the first and second layers 30, 40 can have a conduit portion
comprising at least one deflection conduit. Thus, the first layer 30 has a
first
conduit portion comprising at least one first deflection conduit 35, and the
second
layer 40 has a second conduit portion comprising at least one second
deflection
conduit 45. As used herein, the term "first deflection conduiY' 35 designates
a
hole, or an empty space, in the first layer 30, which hole or empty space
extends
in the Z-direction from the top surface 31 toward the bottom surface 32 of the
first
to layer 30 and is structured and configured to receive a plurality of fibers
in the
course of the process of maldng the fibrous structure 500 of the present
invention. Analogously, the term "second deflection conduit" 45 designates a
hole, or an empty space, in the second layer 40, which hole or empty space
extends in the Z-direction from the top surface 41 toward the bottom surface
42
of the second layer 40 and is structured and configured to receive a plurality
of
fibers in the course of the process of making the fibrous structure 500 of the
present invention.
In some embodiments, the conduit portion extends from the top surface to
the bottom surface through the entire thickness of the layer, thereby causing
the
2o layer to be fluid-permeable, The fibers disposed on the deflection member
during the manufacturing process can be deflected into the deflection conduits
35, 45 under the influence of a fluid pressure differential, for example, by a
vacuum, or otherwise, for example, by a mechanical pressure. The fibers that
have been deflected into the deflection conduits form fibrous "pillows," or
"domes," of the fibrous structure, as will be explained in sufficient detail
below.
The first layer 30 and the second layer 40 are joined together in a face-to-
face arrangement such that some portions of the second layer 40 correspond in
the Z-direction to the deflection conduits 35 of the first layer 30. These
portions
of the second layer 40, by virtue 'of being situated in the Z-direction over
the
deflection conduits 35 of the first layer 30, are elevated in the Z-direction
from the
37
CA 02588743 2007-05-29
X-Y plane, which is co-planar with the bottom surface 32 of the first layer
30, and
thus can form the suspended portions 49 discussed above. As used herein, the
term "correspond" and permutations thereof mean the mutual physical
relationship between two or among several elements, wherein their respective
geometrical projections to the X-Y plane form a common area thereon.
In some embodiments, the reinforcing element 50 is substantially fluid-
permeable. The fluid-permeable reinforcing element 50 may comprise a woven
screen, or an apertured element, a felt, or any combination thereof. Various
types of the fluid-permeable reinforcing element 50 are described in several
1o commonly assigned US Patents, for example, 5,275,700 and 5,954,097, the
disclosures of which are incorporated herein by reference. The reinforcing
element 50 may comprise a felt, also referred to as a "press felY' as is used
in
conventional papermaking. The framework 20 may be applied to the reinforcing
element 50, as taught by commonly assigned U.S. Patents 5,549,790, issued
Aug. 27, 1996 to Phan; 5,556,509, issued Sept. 17, 1996 to Trokhan et al.;
5,580,423, issued Dec. 3, 1996 to Ampulski et a1.; 5,609,725, issued Mar. 11,
1997 to Phan; 5,629,052 issued May 13, 1997 to Trokhan et al.; 5,637,194,
issued June 10, 1997 to Ampulski et al.; 5,674,663, issued Oct. 7, 1997 to
McFarland et al.; 5,693,187 issued Dec. 2, 1997 to Ampulski et al.; 5,709,775
issued Jan. 20, 1998 to Trokhan et al., 5,795,440 issued Aug. 18, 1998 to
Ampulski et al., 5,814,190 issued Sept. 29, 1998 to Phan; 5,817,377 issued
October 6, 1998 to Trokhan et al.; and 5,846,379 issued Dec. 8, 1998 to
Ampuiski et al., the disclosures of which are incorporated herein by
reference.
Alternatively, the reinforcing element 50 may be fluid-impermeable. The
fluid-impermeable reinforcing element 50 can comprise, for example, a
polymeric resinous material, identical to, or different from, the material
used for
making a framework 20 of the deflection member 10 of the present invention; a
plastic material; a metal; any other suitable natural or synthetic material;
or any
combination thereof. One skilled in the art will appreciate that the fluid-
38
CA 02588743 2007-05-29
impermeable reinforcing element 50 will cause the deflection member 10, as a
whole, to be also fluid-impermeable.
It is to be understood that the reinforcing element 50 may be partially fluid-
permeable and partially fluid-impermeable. That is, some portion of the
reinforcing element 50 may be fluid-permeable, while another portion of the
reinforcing element 50 may be fluid-impermeable. For example, in a multi-layer
deflection member 10, wherein the reinforcing element 50 is positioned
adjacent
to the backside 22 of the framework, the fluid-impermeable portion of the
reinforcing element 50 can make the corresponding deflection conduits 35 of
the
lo first layer 30 blind," i. e., those deflection conduits 35 of the first
layer that
correspond to the fluid-impermeable portion of the reinforcing element 50 may
not have fluid-permeability through the first layer 30 (i. e., from the top
side 31 to
the bottom side 32 of the first layer 30).
If desired, the reinforcing element 50 comprising a Jacquard weave can
be utilized. Illustrative belts having the Jacquard weave can be found in U.S.
Pat. Nos. 5,429,686 issued 7/4/95 to Chiu, et al.; 5,672,248 issued 9/30/97 to
Wendt, et al.; 5,746,887 issued 5/5/98 to Wendt, et al.; and 6,017,417 issued
1/25/00 to Wendt, et al., the disclosures of which are incorporated herein by
reference for the limited purpose of showing a principal construction of the
Jacquard weave that can be used in the reinforcing element 50. It is believed
that Yankeeless process described in the above-mentioned patents may benefit
from using the deflection member 10 of the present invention.
In accordance with the present invention, one, several, or all of the
deflection conduits 35 of the first layer 30 may be "blind," or "closed," as
shown in
FIG. 53 and described in commonly assigned US Patent 5,972,813, issued to
Polat et al. on Oct. 26, 1999, the disclosure of which is incorporated herein
by
reference. In the embodiment of the deflection member shown in FIG. 53, the
deflection conduits 35 of the first layer 30 are "closed" by a material 33,
such that
the conduits 35 are impermeable to fluids, including air and water. As the
patent
39
CA 02588743 2007-05-29
cited immediately above describes, polyurethane foams, rubber, and silicone
can
be used to render the deflection conduits 35 fluid-impermeable.
Each of the first layer 30 and the second layer 40 may comprise a
continuous framework, a semi-continuous framework, a pluraiity of discrete
protuberances, or any combination thereof. As used herein, the term
"substantially continuous framework" refers to a layer of the framework 20, in
which layer one can connect any two points on or within that layer by an
uninterrupted line running entirely on or within that layer throughout the
line's
length. That is, the continuous framework 20 has a substantial "continuw in
all
1 o directions parallei to the X-Y plane and is terminated only at edges of
the
deflection member 10. The continuous framework 20 is best shown in FIG. 1 in
which each of the first layer 30 and the second layer 40 comprises a
continuous
framework; FIGs. 3 and 5 in which only the first layer 30 comprises a
continuous
framework; and FIGs. 7 and 13 in which only the second layer 40 comprises a
continuous framework. The term "substantially" (in conjunction with
continuous)
means that while an absolute continuity of the framework 20 is preferred (and
intended while designing and making the deflection member 10), minor
deviations from the absolute continuity may be tolerable as long as those
deviations do not appreciably affect the performance of the deflection member
10 as designed and intended. In a layer comprising a substantialiy continuous
framework, the conduit portion typically comprises a plurality of discrete
deflection conduits dispersed throughout and encompassed by the framework.
The term "substantially semi-continuous framework" refers to a layer of the
framework 20, which has "continuity" in all, but at least one, directions
parallel to
the X-Y plane, and in which layer one cannot connect any two points on or
within
that layer by an uninterrupted line running entirely on or within that layer
throughout the line's length. Of course, the semi-continuous framework may
have continuity only in one direction parallel to the X-Y plane. The semi-
continuous framework 20 is best shown In FIG: 9 in which each of the first
layer
3o 30 and the second layer 40 comprises a semi-continuous framework; FIGs. 7
CA 02588743 2007-05-29
and 11 in which only the first layer 30 comprises a semi-continuous framework;
and FIGs. 3 and 15 in which only the second layer 40 comprises a semi-
continuous framework. By analogy with the continuous pattern described above,
while an absolute continuity in all, but at least one, directions is
preferred, minor
deviations from such a continuity may be tolerable as long as those deviations
do
not appreciably affect the performance of the deflection member 10. In the
layer
comprising a semi-continuous framework, the conduit portion typically
comprises
semi-continuous deflection conduits, i. e., the deflection conduits that can
have
continuity in all but at least one directions parallel to the X-Y plane. Of
course,
yo the semi-continuous deflection conduit may have continuity in only one
direction
parallel to the X-Y plane.
The term "plurality of discrete protuberances" refers to a layer of the
framework 20 comprising discrete, and separated from one another,
protuberances that are discontinuous in all directions parallel to the X-Y
plane.
The framework 20 comprising plurality of protuberances is best shown in FIG.
17
in which each of the first layer 30 and the second layer 40 comprises a
plurality
of protuberances; FIGs. 13 and 15 in which only the first layer 30 comprises a
plurality of protuberances; and FiGs. 5 and 11 in which only the second layer
40
comprises a plurality of protuberances. If the individual layer is formed by a
plurality of discrete protuberances, the conduit portion of such a layer can
be
viewed as one continuous deflection conduit encompassing the discrete
protuberances. As used herein, either one of the terms "conduit portion" and
"at
least one deflection conduiY' generically describes all kinds of the
deflection
conduits: discrete deflection conduits, continuous deflection conduits; and
semi-
continuous deflection conduits, unless otherwise indicated.
In the context of a surface, as opposed to the entire framework, the term
"substantially continuous" surface refers to a surface of the framework 20
(whether it is a surface of the web-side 21 or of the backside 22) wherein one
can connect any two points lying upon that surface by an uninterrupted line
so running entireiy upon that surface throughout the line's length; and the
term
41
CA 02588743 2007-05-29
"substantially semi-continuous" surface refers to a surface of the framework
20,
which has "substantial continuity" in all, but at least one, directions
parallel to the
X-Y plane, and on which surface one cannot connect any two points lying upon
that surface by an uninterrupted line running entirely upon that surface
throughout the line's length.
It is to be understood that the present invention contemplates the
deflection member wherein at least one of the layers 30, 40 comprises any
combination of the continuous pattern, the semi-continuous pattern, and the
pattern comprising a plurality of discrete protuberances. For example, the
first
io layer 30 may comprise a combination (not shown) of the semi-continuous
pattern
and the plurality of discrete protuberances, or a combination (not shown) of
the
continuous pattem and the plurality of discrete protuberances disposed, for
example, within the discrete deflection conduits of the continuous pattern.
Geometry of the framework 20 and the deflection conduits need not be similar
or
repeating within any given layer.
According to the present invention, each of the layers of the multi-layer
structure of the deflection member 10 can have a specific resuiting open area
R.
As used herein, the term "specific resulting open area" (R) means a ratio of a
cumulative projected open area (ER) of all deflection conduits of a given unit
of
2o the iayer's surface area (A) to that given surface area (A) of this unit,
i. e.,
R=ER/A, wherein the projected open area of each individual conduit is formed
by
a smallest projected open area of such a conduit as measured in a plane
parallel
to the X-Y plane. The specific open area can be expressed as a fraction or as
a
percentage. For example, if a hypotheticai layer has two thousand individual
deflection conduits dispersed throughout a unit surface area (A) of thirty
thousand square millimeters, and each deflection conduit has the projected
open
area of five square millimeters, the cumuiative projected open area (ER) of
all
two thousand deflection conduits is ten thousand square millimeters, (5 sq. mm
x
2.000 = 10,000 sq. mm), and the specific resulting open area of such a
3o hypothetical layer is R = 1/3, or 33.33% (ten thousand square millimeters
divided
42
CA 02588743 2007-05-29
by thirty thousand square millimeters). In a dual-layer deflection member 10,
exemplified herein, the first layer 30 can have a first specific resulting
open area
R1, and the second layer 40 can have a second specific resulting open area R2.
The cumulative projected open area of each individual conduit is
measured based on its smallest projected open area parallel to the X-Y plane,
because some deflection, conduits may be non-uniform throughout their length,
or thickness of the iayer -- i, e., from the top surface 31 or 41 to the
bottom
surface 32 or 42, respectively, of the layer 30 or 40, respectively. For
example,
some deflection conduits 35, 45 may be tapered, i. e., have the top-surface
io apertures that are larger or smaller that the bottom-surface apertures
(see, for
example, FIG. 2), as described in commonly assigned US patents 5,900,122 and
5,948,210, the disclosures of which are incorporated herein by reference. In
other embodiments, the smallest open area of the Individual conduit (35, 45)
may
be located intermediate the top surface (31, 41) and the bottom surface (32,
42)
of the layer (30, 40, respectively).
In each individual layer 30, 40, the specific resulting open area of the
individual layer can be at least 1/5 (or 20%), more specifically, at least 2/5
(or
40%), and still more specifically, at least 3/5 (or 60%). According to the
present
invention, the first specific resulting open area R1 may be greater than,
substantiaiiy equal to, or less than the second resulting open area R2.
In some embodiments of the present invention, the first layer 30 may have
a first deformability Di different from a second deformability D2 of the
second
layer 40. As used herein, the "deformability" means an ability of the layer to
change its shape while sufficiently retaining its volume under application of
an
external force, or pressure, typically when the defiection member 10 is
pressed
against a pressing surface, such as, for example, a Yankee drying drum. FlGs.
48 and 49 illustrate an embodiment of the deflection member 10, in which the
first layer 30 has a first deformabiiity D1 greater than a second
deformability D2
of the second layer 40. In FIG. 48, the deflection member 10 is shown free of
pressure. In FIG. 49, the deflection member 10 is shown under application of a
43
CA 02588743 2007-05-29
compressive force directed substantially parallel to the Z-direction, i. e.,
substantially perpendicular to the general plane of the deflection member 10.
Under the pressure, portions of the first layer 30 having a relatively greater
deformability reduce their thickness while expanding laterally (I. e., in
directions
parallel to the X-Y plane). At the same time, the second layer 40 having a
relatively lower deformability does not substantially change its thickness (or
changes to a lesser degree relative to the.. first layer). Some portions of
the
second layer 40 directiy juxtaposed with the first layer 30 can be deflected
into
the first layer 30 under the Z-directional compressive force. Some of the
io suspended portions 49 of the second layer 40 can be deflected into the
deflection conduits 35 of the first layer 30, thereby further selectively
densifying
portions of the fibrous structure 500 disposed therein. (For clarity, the
fibrous
structure is not shown in FIGs. 48 and 49.)
It is contemplated that at least one of the layers may comprise a resilient
material. Moreover, one of the layers may have resiliency, or elasticity,
different
from that of the other layer or layers. As used herein, the terms "resiliency
or
elasticity" mean capability of the deformed (strained or compressed) layer to
substantially recover, on. its own accord, its size and shape after a
deforming
force is removed. More specifically, a resilientiy-deformable layer is capable
to
substantially recover its original, unrestrained thickness almost immediately
after
the deforming force has been removed. Most specifically, in the instance of a
continuous process of maidng the fibrous structure 500 of the present
invention,
such a recovery should occur prior to the next application of the deforming
force
during repeating cycles of the continuous process. The examples of the
resilient
material include, without limitation: silicon rubbers, urethane rubbers,
styrene-
butadiene rubbers, natural rubbers, synthetic rubbers, and any combination
thereof.
It Is also contemplated that at least one of the layers 30, 40 may comprise
a compressible materiai. As used herein, "compressibility" means an ability of
a
3o material to reduce its volume under application of an extemal force. For
44
CA 02588743 2007-05-29
example, the compressible layer can reduce its thickness under application of
a
pressing force, without significantly expanding in lateral directions. The
compressible material which is also resilient can be compressed (such as by a
Z-
directional compressive force) from its free, unrestrained thickness to its
reduced
thickness. Upon release of the force maintaining the material in a compressed
configuration, the material can expand back to have a thickness which is
substantially equal to, or at least about 95% of, its free, unrestrained
thickness.
In the context of a continuous papermaking process, wherein the deflection
member 10 of the present invention is used, such a recovery of the
unrestrained
to thickness should occur prior to the next application of the compressive
force.
The examples of the compressible material include, without limitation, open
and
closed cell foams of any suitable construction, some of which can be combined
with suitable resins.
Process For Makina Deflection Member
A process for making the deflection member 10, according to one
embodiment of the present invention, generally comprises forming at least two
layers 30, 40, each having its own individual structure, and then joining the
two
layers 30, 40 together in a mutual face-to-face relationship such that
portions of
one layer correspond in Z-direction to the deflection conduits of the other
layer,
thereby forming suspended portions 49. Each of the layers 30, 40 can have its
own pattern of the deflection conduit portion. This embodiment of the process
of
making the deflection member 10 of the present invention will be described
more
specifically with reference to FIGs. 19-21.
In FIG. 19, the first layer 30 of the framework 20 is formed using a first
forming surface 100, and the second layer 40 is formed using a second forming
surface 200. As used herein, the term "forming surface" means a surface of a
forming unit structured and configured to support a coating of a suitable
curable
material, such as, for example, a liquid photosensitive resin. The curable
material can be deposited directly to the forming surface, or it can be
deposited
CA 02588743 2007-05-29
to a backing film provided to cover the forming surface to avoid contamination
thereof by the liquid curable material. In the embodiment shown in FIG. 19, a
first curable material 300, comprising, for example, a liquid photosensitive
resin,
is deposited to the first forming surface 100 covered by a first backing film
130;
and a second curable material 400 is deposited to the second forming surface
200 covered by a second backing film 230. The forming surfaces 100, 200 are
formed by first and second forming units comprising a first drum 101 and a
second drum 201, respectively. In the embodiment of the continuous process
shown in FIG. 19, the drums 101 and 201 rotate towards each other, wherein the
1o first drum 101 rotates in a clock-wise direction. It is to be understood,
however,
that at least one of the forming surfaces 100, 200 may comprise a non-circular
or
non-curved element, I. e., one or both the forming surfaces 100, 200 may be
flat
or planar, or have other suitable configurations, as needed.
If desired, the forming surface may comprise a deformable surface, as
described in the commonly assigned US Patent 5,275,700, the disclosure of
which is incorporated herein by reference. When the reinforcing element 50 is
pressed into the deformable forming surface during the process of making, for
example, the first layer 30, the deformable forming surface forms protrusions
that
exclude the curable material from certain areas which, when cured, will lie
along
the backside 22 of the framework 20. This causes the deflection member 10 to
form a so-called utextured" backside 22 having passageways providing texture
irregularities therein. Those texture irregularities are beneficial in some
embodiments of the deflection member 10, because they prevent formation of a
vacuum seal between the backside of the deflection member 10 and a surface of
the papermaking equipment (such as, for example, a surface of a vacuum box or
a surface of a pick-up shoe), thereby creating a"leakage' therebetween and
thus
mitigating undesirable consequences of an application of a vacuum pressure in
a
through-air-drying process of making a fibrous structure 500 of the present
invention. Other methods of creating such a leakage are disclosed in commonly
3o assigned US Patents 5,718,806; 5,741,402; 5,744,007; 5,776,311; and
5,885,421, the disclosures of which are incorporated herein by reference.
46
CA 02588743 2007-05-29
The leakage can also be created using so-called "differentia( light
transmission techniques" as described in commonly assigned US patents
5,624,790; 5,554,467; 5,529,664; 5,514,523; and 5,334,289, the disclosures of
which are incorporated herein by reference. The deflection member is made by
applying a coating of photosensitive resin to a reinforcing element that has
opaque portions, and then exposing the coating to light of an activating
wavelength through a mask having transparent and opaque regions, and aiso
through the reinforcing element.
Another way of creating backside surface irregularities comprises the use
yo of a textured forming surface, or a textured barrier film, as described in
commonly assigned US patents 5,364,504; 5,260,171; and 5,098,522, the
disclosures of which are incorporated herein by reference. The deflection
member is made by casting a photosensitive resin over and through the
reinforcing element while the reinforcing element travels over a textured
surface,
and then exposing the coating to light of an activating wavelength through a
mask which has transparent and opaque regions.
As shown in FIG. 19, the first and second backing films 130, 230 are
provided to protect the first and second forming surfaces 100, 200,
respectively,
and to facilitate removal of the partially completed layers 30, 40 from the
forming
surfaces 100, 200, respectively. In a continuous process of FIG. 19, the
backing
films 130, 230 are traveling in a direction indicated by directional arrows
D3, D4,
respectively. As an example, in the embodiment of FIG. 19, the first backing
film
130 is shown as a single-use film, which is supplied by a supply roll 131 a,
wound
into a take-up roll 131 b, and is typically discarded after the use; and the
second
backing film 230 is shown as comprising an endless belt traveling about return
rolls 231 and being cleaned at a cleaning station 232 and reused.
For the reader's convenience, the process of constructing the individual
layers 30, 40 will be discussed herein in the context of making the first
layer 30.
It should be understood that in the embodiment of FIG. 19, the process of
47
CA 02588743 2007-05-29
constructing the second layer 40 is similar to that of the first layer 30,
with some
possible differences that will be specifically addressed below.
In the embodiment shown in FIG. 19, the process of forming the first layer
30 comprises the following steps. If the deflection member 10 is to have the
reinforcing element, then the first reinforcing element 50 is provided. As
explained above, the first reinforcing element 50 has the upper side 51 and
the
lower side 52. The first reinforcing element 50 is supported by the first
forming
surface 100 such that the lower side 52 of the first reinforcing element 50
faces
the fist forming surface 100 and can be in contact therewith or with the first
io backing film 130 if such backing film is used, as explained above.
Typically, but
not necessarily, the first reinforcing element 50 is placed in a direct
contact with
the first backing film 130. In the continuous process illustrated in FIG. 19,
the
first reinforcing element 50 is supplied from a supply roll 50a. It is also
contemplated in the present invention that the first reinforcing element 50
may be
supplied in the form of an endless belt, as described, for example, in
commonly
assigned US Patent 4,514,345, the disclosure of which is incorporated herein
by
reference. In FIG. 19, the first reinforcing element 50 is traveling in a
first
machine direction MD1.
The use herein of the term "machine direction" is consistent with the
traditional use of the term in papermaking, where this term refers to a
direction
which is parallel to the fiow of the paper web through the papermaking
equipment. In the context of the continuous process of making the deflection
member 10, the "machine direction" is a direction parallel to the flow of the
coating of the curable material (or the reinforcing element where applicable)
during the process of the present invention. It should be understood that the
machine direction is a relative term defined in relation to the movement of
the
coating at a particular point of the process. Therefore, the machine direction
may (and typically does) change several times during a given process of the
present invention. The terms "first machine directionA MD1 and "second machine
3o direction" MD2 refer to the first and second layers 30, 40 being made,
48
CA 02588743 2007-05-29
respectively, as one skilled in the art will readily understand. A term "cross-
machine direction" is a direction perpendicular to the machine direction and
parallel to the general plane of the deflection member 10 being constructed,
or
the X-Y plane.
A coating of the first curable material 300, such as, for example, a liquid
photosensitive resinous material, is applied to the first reinforcing element
50,
and specifically, to its upper side 51. Any technique by which the liquid
curable
material can be applied to the reinforcing element 50 is suitable. For
example, a
nozzle 160, schematically shown in FIG. 19, can be used. Typically, the first
1 o curable material 300 should be evenly applied throughout a width of the
first
reinforcing element 50 or a portion- thereof. The width of the reinforcing
element
50 and a width of the forming surface 100 extend in the cross-machine
direction.
If the first reinforcing eiement 50 has voids designed and structured to be
penetrated by the first curable material 300, such as, for example, the
reinforcing
element comprising a plurality of interwoven yams (shown in FIGs. 1-9 and 11-
18), the curable maferial should be applied such that a sufficient amount of
the
curable material can be worked through the first reinforcing element 50 to
achieve a secure joining therebetween.
Suitable curable materials that can be used for making either one or both
2o of the first and second layers 30, 40 can be readily selected from the many
those
commercially available. For example, the curable material may comprise liquid
photosensitive resins, such as polymers that can be cured or cross-linked
under
the influence of a suitable radiation, typically an ultraviolet (UV) light.
References
containing more information about liquid photosensitive resins Include Green
et
al., "Photocross-linkable Resin Systems," J. Macro-Sci. Revs. Macro Chem., C21
(2), 187-273 (1981-82); Bayer, "A Review of Ultraviolet Curing Technology,"
Tappi Paper Synthetics Conf. Proc,, Sept. 25-27, 1978, pp. 167-172; and
Schmidle, "Ultraviolet Curable Flexible Coatings," J. of Coated Fabrics, 8, 10-
20
(July, 1978). All the preceding three references are incorporated herein by
3o reference. Example of the suitable liquid photosensitive resins are
included in
49
CA 02588743 2007-05-29
the Merigraph series of resins made by MacDermid GRAPHICARTS,
incorporated, of Wilmington, Del. =
The next step is optional and comprises controlling a thickness of the
coating to a pre-selected value. In some embodiments, this pre-selected value
is
dictated by a desired thickness of the first layer 30 and will influence the
resulting
thickness of the deflection member 10. In other embodiments, the thickness of
the coating will become the thickness of the resulting deflection member 10 -
if
the deflection member 10 compdses a single layer. This resulting thickness of
the deflection member 10 is primarily dictated by the expected use of the
1o deflection member 10. For example, when the deflection member 10 Is to be
used in a process for making a fibrous structure, described hereinafter, the
deflection member 10 is typically from about 0.3 mm to about 10.0 millimeters
thick. Other applications, of course, can require thicker deflection members
which can be as high as 30.0 millimeters thick or even thicker, all of which
are
included in the scope of the present invention. Any suitable means for
controlling
the thickness of the first layer 30 can be used in the process. For example,
illustrated in FIG. 19 is the use of a roll 111 a. A clearance between the
roll 111 a
and the forming surface 100, or more specifically between the roll 111 a and
the~
backing film 130, can be controlled manually or mechanically, by any
conventional means (not shown).
Mask
The next step comprises providing a mask 110 and positioning the mask
110 between the coating of the first curable material 300 and a source of
curing
radiation 120. In the instance of a photosensitive resin, the source of curing
radiation 120 may comprise, for example, a mercury arc lamp. The mask 110,
schematically shown in FiGs. 19-25A, comprises a relatively thin and flexible
structure, typically in the nature of fiim, having a top side 110a and a
bottom side
110b opposite to the top side 110a. In some embodiments, the mask 110 may
be juxtaposed in contacting relation with the coating. As schematically shown
in
CA 02588743 2007-05-29
FIG. 20, the mask 110 comprises transparent regions 112 and opaque regions
114. As used herein, the term "opacity" and "opaque" mean lack of transparency
or translucency in certain areas of the mask 110, and designates those areas'
quality of being shaded such as to be impervious or partially impervious to
the
s rays of curing radiation.
The primary purpose of the mask 110 is to shield certain areas of the
coating, i. e., those areas that are shielded by the opaque regions 114, from
exposure to curing radiation. The transparent regions 112 of the mask 110
allow
other (unshielded or partiatly shielded) areas of the coating to be exposed to
and
lo receive the curing radiation which results in hardening, i. e., curing, of
these
unshielded portions. The shielded areas of the coating typically form a pre-
selected pattern corresponding to the desired pattem of the deflection
conduits
35 of the layer being constructed. The mask having a three-dimensional
structure can also be used to imprint a pattern in the coating, as described
below.
1s The mask 110 of the present invention may have multiple differential
opacities, i. e., the mask 110 may have the opaque regions 114 that differ in
opacity. Those differential opacities may comprise discrete opacities and/or
gradient opacities. As used herein, the term "gradient opacity" means an
opacity
having a gradually changing intensity. Gradual opacity does not have a defined
20 "border line" therein that would separate one opacity from the other. That
is, the
gradient opacity is a non-monotone opacity, wherein the change in opacity in
at
least one direction is gradually incremental, as opposed to discrete.
One method of constructing the mask 10 having regions of differential
opacities comprises printing a transparent film to form a pattem of opaque
25 regions having a certain Initial opacity, and then printing the film a
second time to
form a pattem of opaque regions having another opacity different from the
initial
opacity. For example, first the film can be printed with ink to form regions
of the
initial opacity, and then printed again to apply the ink to at least several
of the
regions already having the initial opacity, thereby increasing the opacity of
said
3o several regions. In another method, the differential opacities can be
formed in
51
CA 02588743 2007-05-29
one-step printing, by using a printing roll, such as, for example, a Gravure
roll,
having a differential-depths pattern therein for receiving ink. During
printing, the
ink deposited to the transparent film will have regions of differential
intensities,
reflecting the differential depths of the roll's pattem. Other methods of
forming
opaque regions can be used in the present invention. Such methods include, but
are not limited to, chemical, electromagnetic, laser, heat, etc.
In exemplary embodiments of the mask shown in FlGs. 22A-22C, the
mask 110 has first opaque regions 114a having a first opacity and second
opaque regions 114b having a second opacity (also defined herein as upartiaP'
lo opacity) less than the first opacity. The terms "partially opaque" and
"partially
transparent" may be used herein interchangeably. Each of the first opaque
regions 114a and the second opaque regions 114b may form a discontinuous
pattern of a plural'ity of discrete areas (FIGs. 22A-22C), a semi-continuous
pattern (not shown), or a substantially continuous pattern (not shown). The
second opaque regions 114b may comprise areas adjacent to the first opaque
regions 114a (FIGs. 22A-22C).
The mask 110 can be made in a form of an endless loop (all the details of
which are not shown in FIG. 19 but should be readily apparent to one skilled
in
the art), or it can be supplied from a supply roll (FIG. 50) to a take-up roll
(not
shown). As shown in FiGs. 19 and 50, the mask 110 travels in the direction
indicated by a directional arrow D1, turns under the nip roll 111 a where it
can be
brought into contact with the surface of the first coating 300, travels to a
mask
guide roll 111 b in the vicinity of which it can be removed from the contact
with the
first coating 300.
The mask 110 can 'be made of .any suitable material which can be
provided with opaque and transparent regions. A material in the nature of a
flexible photographic film may be suitable. Such a flexible film can comprise
polyester, polypropylene, polyethylene, cellulosic, or any other suitable
material,
or any combination thereof. The opaque regions 114 can be applied to the mask
110 by any convenient means known in the art, such as, for example, spraying,
52
CA 02588743 2007-05-29
photographic, Gravure, flexographic, or rotary-screen printing. Gradient
opacity
can be formed, for exampie, by printing multiplicity of lines of incrementally
varying opacity, wherein the overall opacity gradually changes in at least one
direction, or by using inks of varying optical density. Gradient opacity can
also be
formed by using a printing roll having gradually-changing differential depths
of
the roll's pattemed depressions receiving ink, which ink, when transferred
from
the roll to the film during printing, will have regions of differential
intensity
reflecting the differential depths of the roll's pattern. Superimposition of
two or
more masks, each having its own pattern of transparent/opaque regions, to form
1o a combined structure having regions of combined opacity is also
contemplated in
the present invention.
Commonly assigned patent application Serial No. 09/346,061, titled
"Papermaking Belts Having Patterned Framework With Synclines Therein And
Paper Made Therewith," filed on 7/1/99 in the name of Trokhan, is incorporated
herein by reference. This application discloses a framework that Is
interrupted
(on its web-side) and subdivided by synclines. The framework, synclines, and
deflection conduits, respectively, impart first, second, and third values of
intensive properties to regions of a paper made on these portions of the belt.
The value of the intensive property of the regions of the paper corresponding
to
the synclines is intermediate to those of the paper regions corresponding to
the
framework and the deflection conduits. For example, if the belt is used as a
through-air-drying belt, the density of the paper regions corresponding to the
synclines may be less than the density of the paper regions corresponding to
the
framework but greater than the density of the paper regions corresponding to
the
deflection conduits; and if the belt is used as a torming wire, the basis
weight of
the paper regions corresponding to the synclines may be greater than the
density
of the paper regions corresponding to the framework but less than the basis
weight of the paper regions corresponding to the deflection conduits.
The mask 110 can be made using a photosensitive material, such as a
so photosensitive film, in which instance the opaque regions can be created by
53
CA 02588743 2007-05-29
selectively exposing predetermined areas of the film to the light. The Ozalid
, or
diazo, process is used to makes copies from a variable optical density
original.
Typically the originals are either black and white or gray scale in nature.
Copies
can be made on different substrates, but for the purposes of this invention
they
can be made on transparent polyester film coated with a sensitized diazo dye.
The translucent original containing the desired image is first placed in
contact
with the coated polyester film. The original and the copy are then exposed to
ultra violet light, typically from a mercury arc lamp. The light first passes
through
the translucent original. The sensitized coating on the copy is destroyed in
those
1o areas of the film that are exposed to the light, uitimately leaving those
areas
transparent. In areas shielded by the original image, the sensitized coating
remains as a latent image. After separation of the originai and the copy, the
copy Is exposed to ammonia gas. The ammonia reacts with the remaining diazo
dye and forms a visibie and essentially permanent image on the film. The
density of the image on the copy is directly proportional to the optical
density of
the image on the original. Such film Is suitabie for use as a mask in the
photo-
polymerization process. Diazo reproduction equipment is commonly sold by the
A. M. Bruning Company of Itasca, IL. A suitable device is the Bruning Model
750. Similar equipment is sold by The Diazit Company, Inc. of Youngsville, NC.
2o A suitable device from Diazit Company is the Executrac.
In some embodiments, the mask 110 has a, three-dimensional topography.
As used herein, the term 'three-dimensional topography" refers to Z-
directional
dimensions of the mask 110, which are greater than the thickness of the
material
the mask 110 is made of. For example, the three-dimensional topography of the
mask 110 may comprise protrusions from the general plane of the mask 110
(when the mask 110 is viewed as disposed on a flat surface). These protrusions
can outwardly extend from the top side 110a, bottom side 110b, or both sides
110a, 110b, of the mask 110 (FIGs. 24 and 25A) and can have regular/repeating
or irregular/non-repeating pattem. In FIG. 24, the mask's bottom side 110b has
a
3o pattern of protrusions 115 extending therefrom. When such a mask 110 is
positioned adjacent to the coating, the pattern of protrusions 115 can be
54
CA 02588743 2007-05-29
imprinted into the coating to form a corresponding pattern of depressions
therein.
FIG. 25A shows the mask 110 of the present invention, comprising two patterns
of protrusions 115: one pattem of protrusions 115a extends from the top side
110a, and the other pattern of protrusions 115b extends from the bottom side
110b of the mask 110. The protrusions 115a extending from the top side of the
mask 110 are hollow and form voids into which the fluid curable material can
flow
to form corresponding protrusions on'the web-side 21 of the framework 20.
Either one of the patterns of protrusions 11 5a, 11 5b may correlate with the
pattern of transparent regions 112 and opaque regions 114. Thus, the patterns
io of protrusions 115a, 115b and the pattem of the opaque/transparent regions
1141112 can work in combination to form a desired three-dimensionai pattern of
the framework 20 of the deflection member 10 (FIG. 25A), whether the mask 110
has the pattem of protrusions 115a extending from the top side 110a of the
mask, the pattem of protrusions 115b extending from the bottom side 110b of
the
mask i 10, or both pattern of protrusions 11 5a, 115b.
The protrusions 115 can be integral or adjunct. As used herein, the
integral protrusions are protrusions that are formed from a material
constituent
with, or inherent to, the mask 110, and as such, the integral protrusions are
not
separable from the rest of the mask 110. One way of forming the integral
protrusions in the mask 110 is schematically shown in FIG. 50. In FIG. 50, a
mask film 118 is supplied in the form of a supply roll. The mask film 118 is
embossed by an embossing roll 190 against a support roli 191. As FIG. 50
shows, the opaque regions 114 can be created, by printing a pattern of the
opaque regions 114 simuitaneousiy with embossing. For example, ink can be
applied to the embossing roil 190, and more specificaliy, to distal surfaces
of the
roll's embossing protrusions, by using, for example, an ink roll 192 partially
submerged into an ink reservoir 193 containing therein a suitable ink. The ink
can also be sprayed to the print roii 192, or directly to the embossing roll
190
(both variations not shown). Alternatively or additionally to depositing the
so suitable ink to the embossing roll 190, the embossed film 118 may be
printed
CA 02588743 2007-05-29
after the step of embossing, for example, by a roll 190a receiving the ink
from a
spray 195 (as schematically shown in FIG. 50 in dashed lines). Other means
known in the art, such as chemical, electromagnetic, laser, heat, etc., can be
used, additionally or altematively, to create opaque regions in the mask 110.
In FIG. 50, when the embossing roll 190 having ink thereon embosses the
film 118, it applies, by contact, the ink to the film 118 in a predetermined
pattern,
for example, a pattern corresponding to the pattem of the embossing
protrusions
on the embossing roll 190. When the mask 110 contacts the coating 300 of the
curable material, the pattern of protru'sions 115 creates a corresponding
t o "negative" pattem of voids in the coating 300. For example, the mask 110
can
been printed such that the distal surfaces of the protrusions 115 are
sufficiently
opaque to preclude curing of areas of the coating corresponding to the opaque
regions 115. Thus, the amount of the liquid resin that is shielded from the
radiation and later washed out, can be reduced by excluding some of that resin
from the shielded portions of the coating prior to the step of curing.
Consequently, by using a three-dimensional mask 110 of the present invention,
one can save a sufficient amount of the curable material.
As used herein, the adjunct protrusions are protrusions that are formed
from the material that is not inherent to the material of the mask 119. The
adjunct protrusions can be formed independently from the mask 110. It does not
exclude, however, the adjunct protrusions 115 formed from the same material as
the mask 110. The adjunct protrusions can be attached (by adhesive, or by a
chemical process, for example) to the mask 110 to form an integral structure
therewith. Alternatively, a pattern of adjunct protrusions may be
independently
supplied and superimposed upon the coating 300, independently from and
without being attached to, the mask 110, as schematically shown in FIG. 51.
The
adjunct protrusions can be made from a variety of suitable materials,
including
organic and non-organic materiais, such as -- without limitation - plastic,
resin,
glass, wood, metal, leather, textile fabric, and any combination thereof.
56
CA 02588743 2007-05-29
In FIG. 51, the three-dimensional mask 110 comprises a first eiement 410
having a pattern of transparent and opaque regions and an embossing element
810. The first element 410 travels about rolls 111 a, 111 b, 111 c, and 111 d;
and
the embossing element 810 is supplied from a roll 810a. Both the first element
410 and the embossing element 810 can be fed into the nip formed between the
coating 300 and the nip roll 111 a, at which point the first element 410 and
the
embossing element 810 come together to form a composite structure in which
the pattern of the transparent and opaque regions 112/114 and the pattem of
the
protrusions 115 work in cooperation to form a desired three-dimensional
pattern
to of the framewoi=k 20 of the deflection member 10. This arrangement is
believed
to provide a greater flexibility In controlling (and changing, if necessary) a
mutual
correlation between the transparent/opaque pattern 112/114 and the pattern of
protrusions 115.
FIG. 52 shows yet another embodiment of the process, in which the mask
110 Is formed by at least two independent elements. In FIG. 52, both the first
element 410 comprising an endless transparent film traveling around rolls 111
a,
111 b, 111 c, and 111 d, and the embossing element 810 are fed into the nip
formed between the coating 300 and the nip roll 111 a. One embodiment of the
embossing element 810, best shown in FIG. 52A, comprises a structure in the
2o nature of an air-permeable grid, which can be formed by, for example,
interwoven filaments, or by means of die forging, die forming, or by any other
means known in the art. The pattem shown in FIG 52a is, of course, one
exemplary embodiment, and variety of other suitable pattems can be used in the
embossing element 810.
As the film 410 and the embossing element 810 travel between the rolls
111 a and 111 b, they form the composite mask 110, wherein the embossing
element 810 creates a three-dimensional pattern in the coating 300 and can, at
the same time, shield selected areas of the coating 300 from the curing
radiation.
The transparent film 410 can also be used to restrict areas of the coating 300
3o from expending beyond the contours of the embossing element 810. If
desired,
57
CA 02588743 2007-05-29
the film 410 can also have a pattern of opaque regions to work in cooperation
with the pattem of the embossing element 810. Alternatively, the embossing
element 810 can be transparent or translucent so that the film 410 alone forms
the opaque regions.
In both embodiments shown in FIGs. 51 and 52, the two elements
comprising the composite three-dimensional mask can be joined together, even
if
temporarily, by, for example, an adhesive (shown, as an example, in FIG. 52 as
being sprayed to the first element 410 by an adhesive applicator 420), or the
embossing element 810, or both, before said elements 410, 810 come into
1o contact. This may prevent the embossing element 810 from being undesirably
submerged into the coating 300 between the rolls 111 a and 111 b, or from
misalignment with the first element 410 when an alignment between the
embossing element 810 and the first element 410 is required.
The next step comprises exposing the first curable material 300 to the
16 curing radiation from the source 120 through the mask 110, thereby inducing
curing of the coating in those areas which are not completely shielded by the
first
opaque regions 114a, I. e., in those areas that can receive the curing
radiation
through the transparent regions 112 or through the partially transparent (or
partially opaque) regions of the mask 110. In the embodiment illustrated in
FIG.
20 19, the backing film 130, the reinforcing element 50, the first curable
material
300, and the first mask 110 all form a unit traveling together from the nip
roll
111 a to the mask guide roll 111 b. Intermediate the nip roll 111 a and the
mask
guide roll 111 b, and positioned at a location where the backing film 130 and
the
reinforcing element 50 are still juxtaposed with the first forming surface
100, the
26 first curable material 300 is exposed to curing radiation generated by the
source
of the curing radiation 120. If the curable material comprises the liquid
photosensitive resin, an exposure lamp, in general, may be selected to provide
illumination primarily within the wavelength that causes curing of the liquid
photosensitive resin. That wavelength Is a characteristic of the liquid
3o photosensitive resin. Any suitable source of illumination, such as mercury
arc,
58
CA 02588743 2007-05-29
pulsed xenon, electrodeless, and fluorescent lamps, can be used. Curing Is
generally manifested by a solidification, or a partial solidification, of the
coating of
the curable material in the exposed areas through a predetermined depth, or
thickness, of the coating. Conversely, the unexposed areas, or portions beyond
the reach of the curing radiation, remain fluid and can be removed from the
coating.
The intensity of the radiation,and its duration depend upon the degree of
curing required in the areas exposed to the radiation. In the instance of the
photosensitiv_e resin, the absolute values of the exposure intensity and time
io depend upon the chemical nature of the resin, its photo characteristics,
the
pattern selected, and the thickness of the coating, or of the desired depth of
its
areas, to be cured. Further, the intensity of the exposure and the angle of
incidence of the curing radiation can have an important effect on the presence
or
abserice of taper in the walls of the pre-selected pattem of the framework to
be
constructed. The disclosure of commonly assigned US Patent 5,962,860, issued
Oct. 5, 1999 in the name of Trokhan et al. is incorporated by reference
herein.
This patent discloses an apparatus for generating controlled radiation for
curing a
photosensitive resin, comprising a reflector having a plurality of elongate
reflective facets that are adjustable such as to direct the curing radiation
2o substantially to a desired direction. The patent further discloses a
radiation
management device comprising a mini-reflector juxtaposed with the source of
radiation for controlling the direction and Intensity of the curing radiation.
The next step comprises removing from the partly-constructed first layer
substantially all the first curable material 300 which was not cured. In the
embodiment shown in FIG. 19, at a point in the vicinity of the mask guide roll
111 b, the mask 110 and the backing film 130 are physically separated from the
composite comprising the reinforcing element 50 and the partly-constructed
first
layer. That composite first layer travels to the vicinity of a first removal
shoe 119,
where a vacuum or other- means may be applied to the composite so that a
59
CA 02588743 2007-05-29
substantial quantity of the still-liquid (uncured) material can be removed
from the
composite.
The second layer 40 can be made by a substantially similar process, from
the second curable material 400. In some embodiments the second layer 40
does not have the reinforcing element permanently joined to the second curable
material 40. During the process of malang the second layer 40, the use of a
second reinforcing element 60 may be desirable, especially when the second
layer 40 comprises a semi-continuous pattern or a pattem of a plurality of
discrete protuberances. The second reinforcing element 60 may comprise a
1o temporary reinforcing element. As used herein, the term "temporary
reinforcing
element" means a reinforcing element that is used during the steps of
constructing a particular (first or second) layer and/or joining the first and
second
layers together, and is removed after serving its intended function so that
the
final deflection member does nor have it. The temporary reinforcing element
can
be made of any suitable material, such as a material in the nature of a
flexible
sheet or film. Such a flexible sheet can comprise polyester, polyethylene,
cellulosic, or any other suitable material, or any combination thereof. It may
be
beneficial to use material having critical surface energy greater than that of
the
curable material.
The foregoing, however, does not exclude embodiments in which the
second layer 40 has the second reinforcing element 60 permanently joined to
the
second layer 40, as is shown, for example, in IFIGs. 11 and 12A. Such a
reinforcing element permanently-joined to the second layer 40 should not
substantially interfere with the fibers' ability to deflect into the
deflection conduits
of the deflection member 10, including the deflection conduits 35 formed in
the
first layer 30. To that effect, such a reinforcing element 60 can comprise,
for
example, a plurality of interwoven yarns, wherein parallel yams are spaced
apart
at a distance sufficient to minimize an interference of the reinforcing
element 60
with the fibers' ability to reach the deflection conduits of the deflection
member
10.
CA 02588743 2007-05-29
The reinforcing element comprising so-called "fugitive tie yarns" may be
beneficially used for the second layer 40. Commonly assigned PCT application
WO 99/14425, published on March 25, 1999, and titled Multiple Layer
Foraminous Belts With Fugitive Tie Yarns, discloses a beit for supporting a
celluiosic fibrous structure in a papermaking process and a method of
producing
the belt. The beit comprises a reinforcing element having two layers, a web-
contacting first layer and a machine-facing second layer, and a pattern lay r
comprising a cured photosensitive resin, the pattern layer having a pluraiity
of
conduits therethrough. The two layers of the reinforcing element are joined
1o together by either integral or adjunct tie yarns such that at least a
portion of the
tie yarns which lies within the conduits is removable after the photosensitive
resin
has been cured. These "fugitiven tie yarns are substantially transparent to
actinic
radiation and can be removed by chemical or mechanical processes when they
are no longer needed to stabilize the relationship between the web-facing
layer
and the machine-facing layer of the reinforcing element. In particular, the
portion
of the fugitive tie yarns that lies within the conduits can be removed so that
belt
properties, such as projected open area, are substantially isotropic across
the
belt. A means to remove the fugitive adjunct tie yarns may include a
combination
of solubilization and mechanical energy provided by a showering systems that
2o are part of the belt-maldng and papermaidng processes. Suitable materials
for
the fugitive tie yams comprise those that can be controliabiy removed by
chemical or mechanical means. The disclosure of PCT application WO
99/14425 is incorporated herein by reference.
In FIG. 19, the temporary reinforcing element 60 is shown in the form of
an endless band traveling in a second machine direction, indicated by a
directional arrow MD2, about rolls 240, 241, and 242. It is to be understood,
however, that the temporary reinforcing element 60 may be supplied in the form
of a supply roll to be wound into a take-up roll, analogously to the
arrangement
comprising the supply roll 131 a and the take-up roll 131b used for the
backing
so film 130, described above.
61
CA 02588743 2007-05-29
Analogously to the steps of making the first layer 30, a coating of the
second curable material 400 and the temporary reinforcing element 60 can be
supported by the second forming surface 200. The second curable material 400
can be deposited by using, for example, a nozzle 260. The second curable
material 400 may be identical to, or different from, the first curable
material 300.
Controlling the thickness of the coating of the second curable material 400 to
a
pre-selected value can be accomplished by, for example, a nip roll 211 a. As
has
been explained above, the resulting thickness (or caliper) of the deflection
member 10 is formed by the combined thickness of the first layer 30 and the
1o second layer 40. The coating of the second curable material 400 is exposed
to a
curing radiation from a second source 220 of the curing radiation, through a
second mask 210, having a pattem of transparent and opaque regions. The
second mask 210 travels in the direction indicated by a directional arrow D2,
turns under the nip roll 211a where the second mask 210 can be brought into
contact wtth the surface of the second coating 400, travels to a mask guide
roll
211 b in the vicinity of which the second mask 210 can be removed from the
contact with the second coating 400. Then, substantially all the second
curable
material 400 which was not cured is removed from a partly-made second layer
40, by, for example, a second removal shoe 219, where a vacuum can be
2o applied to the composite so that a substantial quantity of the liquid
uncured
material can be removed from the composite.
After the first and second layers 30, 40 are substantially formed, the first
layer 30 and the second layer 40 are brought together in a face-to-face
relationship at a nip indicated In FIG. 19 as "N1." Any conventional means for
bringing the first and second layers 30, 40 together may be utilized. In the
embodiment of FIG. 19, the first layer 30 travels around a first nip roll 140,
and
the second layer 40 travels around a second nip roll 240. The nip N1 is formed
between respective outer surfaces of the nip rolls 140 and 240. Mutual
alignment of the two patterns - the first and second layers 30, 40 - may be
3o required, so that a desired combined three-dimensional pattern formed by
superimposition of two respective patterns can be obtained at the nip N1.
62
CA 02588743 2007-05-29
According to one embodiment of the process of the present invention, the
first layer 30 and the second layer 40 are cured to the extent that their
respective
surfaces of contact retain some adhesive properties sufficient to enable the
first
and second layers 30, 40 to be securely joined upon contact therebetween. That
is, when the first and second layers 30, 40 are brou,ght together at the nip
N1, the
outer surfaces of the first and second layers 30, 40 facing one another retain
sufficient amount of surface energy and are capable of being joined together
by
virtue of not being completely hardened. With reference to FIG. 19, the top
surface 31 of the first layer 30 and the bottom layer 42 of the second layer
40,
lo before being brought together in the nip N1, may not be cured to a complete
hardness and can remain in a partially cured condition to retain a sufficient
amount of surface energy to enable joining of the first and second layers 30,
40
together.
The joining of the first and second layers 30, 40 in the nip N1 may be
facilitated by an application of pressure exerted by the first and second nip
rolls
140, 240. At the nip Ni, the first and second surfaces 30, 40 are pressed
against each other, and the combined structure travels farther from the nip N1
to
a nip N2 during a predetermined period of time. Any conventional means may be
used to impart the pressure upon the first and second layers 30, 40 to join
securely them together. In FIG. 19, auxiliary press rolls 150 and 250 are
schematically shown to press the first and second layers 30, 40 towards each
other.
After the partly-formed deflection member 10, comprising the first and
second layers 30, 40 joined together, exits the nip N2, It can be brought into
the
vicinity of a resin wash shower 124 and a resin wash station drain 125, at
which
point the composite can,be thoroughly washed with water or other suitable
liquid
to remove essentially all of the remaining uncured (and still liquid) material
300,
400 which can be discharged from the system through the resin wash station
drain 125. Further, if desired, an additional resin removal shoe (not shown)
may
3o be utilized to remove, by vacuum or otherwise, any residual uncured
material
63
CA 02588743 2007-05-29
300, 400. Then, a final curing can be performed, for example, from sources 121
and 122 of the curing radiation disposed at opposite sides of the composite
framework 20 being formed, to complete the process of joining the layers 30,
40,
and hardening the composite structure, thereby forming the deflection member
10 of the present invention. If the temporary reinforcing element 60 has been
used, the temporary reinforcing element 60 can be separated or removed from
the second layer 40 at the nip N2 or later when the deflection member 10 is
substantially formed, depending on a specific embodiment of the process.
The present invention contemplates an embodiment in which one or both
-io of the first and second layers 30, 40, or at least their respective
surfaces of
contact 31, 42, comprise(s) a chemically-active ingredient or ingredients, to
enable, or facilitate, joining of the first and second layers 30, 40. As used
herein,
the "chemically-active ingredient" means a substance that is capable of
forming,
under certain conditions, chemical bonds or other favorable associations with
another material in contact therewith. Suitable materials include primers and
coupling agents. The primers can comprise multi-functional and multi-
component formulations, One of the functional groups is capable of forming
chemical bonds with the material of the first layer while another functional
group
or groups bond(s) or beneficially associate(s) with the second layer. An
example
of such a material for potentiating the joining of a methacrylate photo-
polymer
layer and a polyester layer would be an acrylate-terminated polybutadiene.
Such
an ingredient can also have a secondary binder such as a vinyl copolymer
(vinyl
acetate/chloride/alcohol terpolymer). Suitable coupling agents include the
titanate and zirconate coupling agents sold by Kenrich Petrochemicals Inc. of
Bayonne, NJ. Without being bound by theory, it is believed that these tetra-
functional organo-metallic coupling agents based on titanium and zirconium
work
because the central metal's tetravalency is conducive to erectron sharing
which in
turn enhances adhesion between dissimilar materials.
The chemically-active ingredient or ingredients may be inherently present
in at least one of the first curable material 300 and the second curable
material
64
CA 02588743 2007-05-29
400. Altematively, the chemically-active ingredient or ingredients may be
added
to at least one of the first and second curable materials 300, 400, or at
least one
of the first and second layers' surfaces of contact. In FIG. 19, a first
chemically-
active ingredient is schematically shown as being sprayed on the top surface
31
of the first layer 30 with an applicator 127; and a second chemically-active
ingredient is schematically shown as being sprayed on the bottom surface 42 of
the second layer 40 with an applicator 227. The chemical composition of such
chemically-active ingredient(s) is dictated primarily by the chemical
compositions
of the first and second curable materials 300, 400. For example, if the first
and
io second curable materials 300, 400, are identical and comprise a liquid
photosensitive resin, an additional amount of the liquid photosensitive resin
may
be applied to one or both surfaces 31, 42 to be joined. After joining,
additional
UV radiation may be supplied to cross-link the applied resin with residual
monomer sti8 present in layers 30 and 40.
One skilled in the art will appreciate that in lieu of, or in addition to, the
first
and second chemically-active ingredients, various adhesive materials may be
utilized to enable or facilitate joining of the first and second layers 30, 40
together. It is contemplated that in such embodiments, at least one of the
first
and second layers 30, 40 may be completely cured to the final hardness prior
to
the step of joining.
According to another embodiment, one or both of the first and second
layers 30, 40 may be made by first providing a ply of a suitable material
having a
pre-selected thickness and then forming a conduit portion therein. For
example,
a plurality of the discrete deflection conduits may be formed by any
conventional
means known in the art, such as by drilling, by a chemical process, by
printing,
by a laser cutting, etc. If one of the layers comprrises a semi-continuous
pattern
or a pattern comprising a plurality of discrete protuberances, it can be
formed by
providing individual discrete elements and attaching these individual discrete
elements to the other layer.
CA 02588743 2007-05-29
FiGs. 22A-25A schematically show several embodiments of the deflection
member 10 of the present invention, and a process for making such a deflection
member 10 using the mask 110 of the present invention, having differential
opacities and gradient opacities. The following process may also be used for
constructing any of the individual layers of the composite framework 20
comprising a multi-layer structure. To the extent that a construction of one
of the
layers 30, 40 is concerned, many steps of this process are analogous to the
process steps described above in the context of.making an individual layer,
and
therefore would be readily appreciated by one skilled in the art without
repeating
io all the details common for the both processes.
As illustrated in FiGs. 22A-25A, and mentioned above, the mask 110 has
the transparent regions 112 and the opaque regions 114. The opaque regions
114 comprise at least the first opaque regions 114a having the first opacity,
and
the second opaque regions 114b having the second opacity different from the
first opacity. For example, the first opacity may be greater than the second
opacity. The first opaque regions 114a may have optical density that is
greater
than that of the second opaque regions 114b. In the exemplary embodiments of
FIGs. 22A-25A, the first opacity is the opacity that completely precludes
curing of
the areas (defined herein as "first areas") of the curable material shielded
by the
first opaque regions. In the instance of the curable materfal comprising a
photosensitive resin, most typically such first opaque regions 114a are solid
black
that completely blocks light of an activating wavelength. At the same time,
the
mask's second opaque regions 114b, having the second opacity, allow the areas
of the coating shielded thereby (defined herein as "second areas") to
partially
cure, i. e., to cure to a certain depth, or thickness, while the rest of the
thickness
of those second areas remains uncured. In the Instance of the curable material
comprising a photosensitive resin, such first opaque regions 114a may be
"gray"
that allows the curing light of an activating wavelength to penetrate the
coating to
a certain depth thereof, I. a., through a certain predetermined portion of the
3o coating's thickness.
66
CA 02588743 2007-05-29
When the coating of the curable material is subjected to the curing
radiation from the source 120 through the mask 110 having regions of
differential
opacity, the first areas of the coating, which are shielded by the first
opaque
regions 114a, remain uncured (e. g., liquid) through the entire thickness of
the
coating, while the second areas of the coating, which are shielded by the
second
opaque regions 114b, remain uncured only through a certain portion of the
thickness of the coating, as best shown in FIGs. 23-25. At a given intensity
of
the curing radiation, the second opacity can be chosen such as to pre-select
and
control a desired extent of penetration of the curing radiation to cure the
coating
io through a desired depth, or thickness, defined herein as "second
thickness." The
transparent regions 112 allow the rest of the coating (defined herein as
"third
areas") to cure the curable material through the entire thickness of the
coating
(defined herein as "first thickness"), as has been explained above.
As schematically shown in FIGs. 22A-25A, various shapes and cross-
sectional configurations of the suspended portions 49 can be created by using
the mask of the present invention comprisfng regions having differential
opacities
and gradual opacities. For convenience, as used in FIGs. 22A-25, reference
numerals having parenthetical numerical suffix designate various exemplary
embodiments of the first opaque regions 114a (from 114a(1) to (114a(8)), the
second opaque regions 114b (from 114b(1) to 114b(12)), and the suspended
portions 49 (from 49(1) to 49(12)) and their back surfaces 49b (from 49b(1) to
459b(12)); while the reference numerals (1 12a, 1 14b, 49, and 49b) used
without
said suffix generically designate these elements.
In FIGs. 22A-25, the first opaque regions 114a of the mask 110 cause the
corresponding first areas of the coating to remain uncured through their
entire
thickness and thus be removed from the partly-formed deflection member to form
discrete deflection conduits 35. The second opaque regions 114b, adjacent to
the first opaque regions 114a, cause the corresponding second areas of the
coating to cure through only a portion of the entire thickness of the coating,
i. e.,
through the second thickness, to form the suspended portions 49. The rest of
67
CA 02588743 2007-05-29
the coating, i. e., the third areas corresponding to the transparent regions
112 of
the mask 110 is exposed to the curing radiation through the transparent
regions
112, to cure through the entire thickness of the coating. The resulting
structure,
best shown in cross-sectional views of FIGs. 23-25, comprises the pluraliiy of
bases 30 and plurality of suspended portion 49 laterally extending from the
plurality of bases 30.
For example, as shown in FIGs. 22A and 23, some of the second opaque
regions 114b, specifically 114b(1) through 114b(4), are adjacent to and
surround
the diamond-shaped discrete first opaque regions 114a. After the curing is
1 o complete, the resulting framework 20 comprises a substantially continuous
pattem having a plurality of diamond-shaped discrete deflection conduits 35
dispersed throughout the framework 20. Each of the deflection conduits 35 is
surrounded at the web-side 21 by the suspended portions 49 formed from the
coating's second areas which are cured only through a portion of the coating's
thickness (FIG. 23).
In FIGs. 22A and 23, the mask's second opaque region 114b(1)
comprises a constant, non-gradient opacity, while each of the second opaque
regions 114b(2), 114b(3), and 114b(4) comprises a gradient opacity. As has
been noted above, using the gradient opacity, one can create suspended
portions having differential and gradually changing thickness, as well as the
back
surfaces 49b having differential shapes. For example, in FIG. 23, the back
surface 49b(1) of the suspended portion 49(1) is substantially microscopically
monoplanar and parallel to the X-Y plane, because during the curing it was
superimposed with (and thus partially shielded by) the mask's opaque region
having a constant, non-gradient opacity. At the same time, the back surface
49b(2) of the suspended portion 49(2) is tapered, or "angled" relative to the
backside 22, because during the curing it corresponded to the mask's opaque
region having a gradient opacity. One skilled in the art wili appreciate that
a
degree of a taper and/or shape of the back surface 49(b) created by using the
3o gradient opacity regions depend(s) upon a particular pattern of
distribution of the
68
CA 02588743 2007-05-29
gradient opacity in the opaque regions. As an example, the suspended portions
49(3) and 49(4) are shown in FIG. 23 as having their back surfaces 49b(3) and
49b(4), respectively, curved in mutually opposite directions. Such shapes of
the
back surface 49b of the suspended portions 49 can be created by using non-
linearly changing gradient opacity.
While the suspended portions 49 shown in FIGs. 22A and 23 comprise
"cantilever" suspended portions, FIGs. 22B and 24 show "bridging" suspended
portions 49, as explained above. As viewed in the cross-section, each of the
suspended portions 49 shown in FIG. 24 bridges two adjacent bases 30. Here
io again, the second opaque region 11 4b(5) of the mask 110 has monotonous,
non-
gradient, opacity, and the resulting corresponding suspended portion 49(5) has
a
constant thickness and a substantially planar back surface 49b(5) parallel to
the
backside 22 of the resulting framework 20. At the same time, the second opaque
regions 114b(6) and 114b(7) have patterns of gradient opacities therein, and
the
suspended portions 49(6) and 49(7) have their respective back surfaces 49b(6)
and 49b(7) shaped as curvatures. The suspended portion 49(8), corresponding
to the second opaque region 114b(8), has its back surface 49b(8) comprising a
sinusoidal, or "wavy" shape In the cross-section. The framework 20 exemplified
in FIGs. 22B and 24 is substantially continuous, with a plurality of discrete
2o deflection conduits 35 dispersed therethrough, a central portion of each of
the
deflection conduits 35 being partially "covered" by a suspended portion 49.
FIG.
24 also shows the paftern of protrusions 115 extending from the mask's bottom
side 110(b), as described above.
In FIGs. 22C and 25, showing another exemplary embodiment of the
2s framework 20 comprising the suspended portions 49, each of the second
opaque
regions 11 4b of the mask 110 is shown to have a constant, non-gradient
opacity.
However, these opacities are differential relative to one another: the second
opaque regions 114b(10) and 114b(12) are less opaque than the second opaque
regions 114b(9) and 114b(11). Consequently, the suspended portions 49(10)
3o and 49(12) corresponding to the second opaque regions 114b(10) and
114b(12),
69
CA 02588743 2007-05-29
respectively, have been cured through a greater thickness and in the result
are
thicker than the suspended portions 49(9) and 49(11) corresponding to the
second opaque regions 114b(9) and 114b(11), respectively. In FiGs. 22C and
25, there are two kinds of the first opaque regions 114a, based on their
geometrical pattern: the first opaque regions 114a(9) comprising a plurality
of
discrete circular areas, each encompassed by the discrete transparent region
112; and the first opaque regions 114a(10) comprising areas separated by the
pattem of the first and second opaque regions 114a, 114b. Both kinds of the
first
opaque regions 114a has the opacity that completely precludes the
lo corresponding third areas of the coating from curing throughout the entire
coating's thickness. The resulting framework 20 comprises a plurality of
discrete
protuberances, each having therein a discrete deflection conduit 35 extending
through the entire thickness of the framework 20 from the web-side 21 to the
backside 22, and a plurality of the suspended portions 49 that bridge mutually
adjacent protuberances. As is explained herein above, these suspended
portions 49 can have differential thickness.
FIG. 25A shows another exemplary embodiment of the process for making
the deflection member 10 of the present invention, using the mask 110 of the
present invention comprising the pattern of transparent/opaque regions and a
pattern of a three-dimensional topography. The mask's three-dimensional
topography comprises protrusions 11 5a outwardly extending from the top side
110a of the mask, and protrusions 11 5b outwardly extending from the bottom
side 111 b of the mask 110. When the mask 110 is placed on the top of the
coating of the fluid curable material 30, the pattern of protrusions 115b,
extending from the bottom side 110b of the mask 110, is submerged into the
coating thereby excluding the fluid curable materiai 30 therefrom and thus
forming a corresponding pattem of depressions in the coating; and the pattem
of
protrusions 115a, extending from the top surface 110a of the mask 110 and
comprising voids structured and configured to receive the fluid curable
material,
3o receives the curable material 30 that fills these voids to form
corresponding
CA 02588743 2007-05-29
projections 39 on the would-be web-side '21 of the framework 20 being
constructed.
The pattern of opaque regions of the mask 110 shown in FIG. 25A has
differential opacities, as described above. The first opaque regions 1 y4a
completely block the curing radiation, thereby,causing the curable material
corresponding thereto (i. e., the first areas) to remain liquid. Upon removal
of
that liquid curable materiat, conduits 35a and 35b are formed, the conduits
35b
being formed in the suspended portions 49. The second opaque regions 114b
allow the curing radiation to cure the coating to a certain depth, thereby
forming
lo the suspended portions 49. The transparent regions 112 cause the curing
radiation to cure the third areas of the coating through the entire thickness
of the
third areas. It should be noted that in FIGs. 23-25A, differential shading of
the
framework 20 is used only for fllustrative purposes and convenience of a
reader,
to distinguish differential portions of the framework 20 being made. A single
layer of the framework 20, when made using the mask 110 illustrated in FIGs.
22A-25A, is an integral structure having no visual "border lines" separating
parts
thereof.
It is to be understood that the mask 110 may have a third, fourth, fifth, etc.
differential opacities, which Would enable one to create a variety of three-
2o dimensional pattems of the framework 20 of the present invention, all of
which
are contemplated by, and within the scope of, the present invention. The
foregoing embodiments of the deflection member 10 of the present invention
should be construed as mere examples which are intended to illustrate a
variety
of possible variations and permutations of the mask 110 and the deflection
member 10, but not to limit the present invention. One skilled in the art
would
appreciate that virtually unlimited number of embodiments and variations of
geometrica( shapes and mutual positions of the bases 30 and the suspended
portions 49 may be formed using the mask 110 and based on the principles of
the present invention described herein, which are all included in the scope of
the
present invention.
71
CA 02588743 2007-05-29
After the uncured, or liquid, material is removed, the cured, or hardened,
material is left to form the framework 20 having a pre-selected pattem. The
third
areas that have been cured throughout the entire thickness of the coating form
the bases 30; and the second areas that have been partiaiiy cured through only
the second thickness form the suspended portions 49. Since the curable
materiai can be cured from that surface of the coating which will form the web-
surface 21 of the framework 20 being made, the second thickness extends from
the web-side 21 towards the backside 22 of the framework 20 being made.
Therefore, when the liquid uncured material is removed, the suspended portions
io 49 are disposed at a distance, i. e., "elevated," or "suspended," from the
plane
defined by the bottom surface of the layer being made, or from the backside 22
of the framework 20, to form void spaces between the suspended portions 49
and the plane defined by the backside 22. iit is to be understood that when
this
process is used for making an individual layer (30, 40) of a muiti-layer
composite
defiection member 10, the curing of the coating may be conducted from either
the top side (31, 41) or the bottom side (32, 42) of the individual layer (30,
40)
being made, in which instance the suspended portions 49 can be elevated from
the plane defined by that surface which is opposite to the surface first
receiving
curing radiation.
The distance between any given suspended portfon 49 and the X-Y plane
is defined by a thickness of the uncured material that has been removed from
the
member being constructed. The suspended portions 49 can laterally extend
from the bases 30 in at least one direction. As used herein, the term
"lateral" and
permutations thereof generally mean an orientation which is different from the
Z-
direction, including but not limited to any direction that is substantially
parallel to
the X-Y plane. It is to be appreciated that while it is said that the
suspended
portion 49 "extends" in at least one of the directions substantiaiiy paraiiel
to the
X-Y plane, the suspended portion 49 itself, as a whole, does not need to be
paraliel to the X-Y plane.
3o Fibrous Structure
72
CA 02588743 2007-05-29
One use of the deflection member 10 is in the production of an improved
fibrous structure, such as, for example, a paper web. With reference to FiGs,
26-
41, the fibrous structure 500 of the present invention comprises a first
plurality of
micro-regions (or simply, a first region) 510 having first properties, and a
second
piuraiity of micro-regions (or simply, a second region) 540 having second
properties. The first properties are different, in at least one respect, from
the
second properties.
As shown in FIGs. 26-29, the first region 510 is substantially
macroscopically-monoplanar and defines a first plane parallel to the X-Y
plane.
io The first region 510 has a first elevation. The second region 540 outwardly
extends from the first region 510 (or from the first plane defined thereby) in
a
direction perpendicular to the first plane (i. e., the Z-direction), to define
a second
elevation. It is to be understood that the "second elevation" need not be
uniform,
i. e., differential portions which form the second region 540 can have
differential
heights.
In one embodiment, the first plurality of micro-regions 510 has a relatively
high density, and the second plurality of micro-regions 540 has a relatively
low
density. In another embodiment, the first and second pluralities of micro-
regions
510, 540 can differentiate by their respective basis weight. For example, the
second plurality of micro-regions 540 can have a basis weight that is greater
than
that of the first plurality of micro-regions 510. All such embodiments are
included
in the scope of the present invention.
According to the present invention, the second region 540 comprises
fibrous domes 530 that extend generally upwardly from the first plane, and a
fibrous cantilever portions 549 that laterally extend from the fibrous domes
530 at
the second eievation. As used herein, the term "dome" is descriptive with
respect to the fibrous web's cross-section perpendicular to the X-Y plane. The
fibrous domes can comprise a continuous pattern, a semi-continuous pattem, a
plurality of discrete elements, or any combination thereof. The term "fibrous
3o pillow" (or simply "pillow") 540 is used herein to define the dome 530 and
the
73
CA 02588743 2007-05-29
cantilever portion 549 extending therefrom, if such a cantilever portion 549
exists
with respect to that dome 530. The fibrous pillows can also comprise a
continuous pattem, a semi-continuous pattem, a pluraiity of discrete elements,
or
any combination thereof.
Because the fibrous cantilever' portions 549 laterally extend from the
fibrous domes 530 at the second elevation, a plurality of pockets 560
comprising
substantially void spaces can be formed between the first region 510 and the
fibrous cantiiever portions 549. Thus, the fibrous cantilever portions 549
form
characteristic pockets 560 defined between the area of the first region 510,
the
to fibrous domes 530 extending therefrom, and the fibrous cantilever portions
549,
as shown in FiGs. 27 and 29-41. In large part due to the existence of these
substantially void pockets 560, the fibrous structure 500 of the present
invention
is believed to exhibit very high, for a given basis weight, absorbency
characteristics. The pockets 560 are characterized by having none or very
iittle
amount of fibers therein. One skilled in the art will appreciate that due to a
process of making the fibrous structure 500, as discussed below, and because
of
a highly flexible nature of the fibers and the fibrous structure 500 as a
whole,
some amount of individual fibers present in the pockets 560 is tolerable as
long
as those fibers do not interfere with the designed pattern of the fibrous
structure
2o 500 and its intended properties. In these context, the term "substantially
void"
spaces / pockets is intended to recognizes that due to a highly flexible
nature of
the fibrous structure 10 and individual fibers comprising it, some
insignificant
amount of fibers or their portions may be found in the pockets 560, as long as
these pockets 560 could be easily distinguished from the rest of the fibrous
structure 500, as best shown in photomicrographs of FIGs. 32-41. A density of
the pockets 560 is not greater than 0.005 gram per cubic centimeter (g/cc),
more
specifically, not greater than 0.004 g/cc, and still more specifically not
greater
than 0.003 g/cc.
Typically, .the fibrous cantiiever portion 549 is oriented in a general
3o direction parallel to the first plane, as schematicaiiy shown in FIG. 30
and 31 and
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CA 02588743 2007-05-29
photomicrographs of FIGs. 32-41. It should be understood that while it is said
that the fibrous cantilever portions 549 is oriented, or "extend," parallel to
the first
plane, the fibrous cantilever portions 549 themselves do not have to be
parallel to
the first plane. As photomicrographs of FIGs. 32-41 show, the fibrous
cantilever
portions 549 can be angled relative to the first plane, curved, or otherwise
positioned. Again, one skilled in the art should appreciate that the fibrous
and
highly flexible nature of the fibrous structure 550 can cause many of the
fibrous
cantilever portion to be irregularly and non-similarly positioned relative to
one
another, even if those cantilever portions have been formed by identical or
similar
to elements of the deflection member 10 of the present invention.
According to the invention, a maximal horizontal dimension of the pocket
560 can be at least 0.3 millimeter, in some embodiments at least 0.7
millimeter,
in still some embodiments at least 1.1 millimeter, and still in other
embodiments
at least 1.5 millimeter. As used herein, the "maximal horizontal dimension" of
the
pocket 560 is defined as the longest parameter of the pocket area, as viewed
in
a cross-section perpendicular to the first plane, and measured in the
direction
substantially parallel to the first plane. Stated differently, the maximal
horizontal
dimension of the pocket 560 is a projected (i. e., "horizontal") length of the
fibrous
cantilever portion 549, as measured from a side wall 543 of the fibrous dome
530
of the pillow 540 (FIGs. 30 and 31). It is again pointed out that because of
the
fibrous and highly flexible nature of the product, in some embodiments it may
be
difficult to precisely outline the exact boundaries of the pocket 560, and
some
approximation may be needed, for example, exclusion of some individual fibers
extending from a mass of the fibrous dome 530 and/or its cantilever portion
549.
Still, one skilled in the art can easily reproduce the images of the fibrous
structure
500, similar to those shown in photomicrographs of FIGs. 32-41, and make all
the necessary measurements, using the following equipment.
Photomicrographs shown in FIGs. 32-41 were taken with a Hitachi S-
3500N Scanning Electron Microscope (SEM) in a "normal mode. Acceleration
voltage was set from 3 kV to 5 kV to acquire a crisp and clean image.
CA 02588743 2007-05-29
Magnification was set anywhere from 35X to 50X, in order to view the level of
detail desired. All samples were mounted on metal sample holders and gold
coated for imaging. Samples were mounted such as to acquire a cross-sectional
view of the web structure.
One embodiment of the fibrous structure 500, schematically shown in
FIGs. 26 and 27, has the first piuraiity of micro-regions 510 comprising a
substantially continuous network, and the second plurality of micro-regions
540
comprising a plurality of pillows. As used herein, for convenience, the
reference
numeral 540 may be used to indicate both the "second plurality of micro-
regions"
to (or the "second region") and the pillow. The first plurality of micro-
regions 510 is
continuous, macroscopically monoplanar, and forms a pre-selected pattern
corresponding to the pattem of the presumably continuous web-contacting side
21 of the framework 20 of the deflection member 10 on which the fibrous
structure 500 has been made. The pillows 540 are dispersed throughout the
whole of the network region, separated from one another by the network region,
and extend outwardly from the first plane formed by the network region. FIGs.
32-41 show photomicrographs of several embodiments of the fibrous structure of
the present invention, having the pockets and comprising the first plurality
of
micro-regions in the form of a substantially continuous network, and the
second
plurality of micro-regions in the form of a plurality of discrete fibrous
piilows, each
comprising a fibrous dome portion and a fibrous cantilever portion.
Another, prophetic, embodiment of the fibrous web 500, shown in FIG. 28,
comprises the first plurality of micro-regions 510 forming a semi-continuous
pattern, and the second plurality of micro-regions 540 forming a semi-
continuous
pattem of the pillows 540. Still another prophetic embodiment (not shown) of
the
fibrous structure 500 comprises the first plurality of micro-regions 510
forming a
pattern of discrete areas, while the second plurality of micro-regions 540
forms a
substantialiy continuous pattern of the pillows 540.
The novel fibrous structure 500 of the present invention has a sufficiently
so increased surface area, relative to comparable fibrous structures of the
prior art.
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CA 02588743 2007-05-29
By "comparable" fibrous structures of the prior art it is meant those prior
art
fibrous structures that have approximately the same basis weight and the
overall
pattem of the pillows, as the structure 500 of the present invention. One
skilled
in the art wili appreciate that the increased surface area provides conditions
for
the increased absorbency of the fibrous structure 500. The surface area of the
fibrous structure can be estimated and measured as described herein below. A
cross-sectional parameter P of the pillow (FIG. 30), representative of the
surface
area of the second region 540, is measured and approximated, if needed, based
on the photomicrographs of the fibrous structure 500, exemplified in FIGs. 32-
41.
.1o As used herein, the term "perimeteru of the pillow 540 is defined by a
line
approximately outiining an overall configuration, or shape, of the individual
pillow
540, as viewed in a cross-section perpendicular to the first plane.
In FIGs. 32-41, one skilled in the art can readily draw a line generally
outlining the configuration of a given pillow 540 and disregarding individual
fibers
that "stick out." For example, FIG. 30 is intended to approximately replicate
(without regard to the scale) the configuration of the pillow 540 shown in the
photomicrograph of FIG. 39; and FIG. 31 is intended to approximate (also
without regard to the scale) the configuration of the pillows 540 shown in the
photomicrograph of FIG. 36. In FIGs. 30 and 31, the. points 541 ' and 542
conventionally designate the "beginning" and the "end" of the line
representing
the perimeter P of the pillow 540; and a distance between the points 541 and
542 defines a cross-sectional base B of the pillow 540. Stated differently,
the
points 541 and 542 approximate the points at which the line representing the
parameter P intersects the plane of the first region 510. Then, with the
understanding that the resuiting line only approximates the cross-sectional
perimeter P of the given pillow 540, one can easily measure the length of the
resulting line representing the parameter P, as well as the length of the base
B of
the pillow 540.
According to the present Invention, a ratio P/B of the cross-sectional
perimeter P of the pillow 540 to a cross-sectional base B of the same pillow
540,
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CA 02588743 2007-05-29
taken in a cross-section perpendicular to the first plane, is at least 411, in
other
embodiments is at least 6/1, still in other embodiments, is at least 8/1, and
yet in
other embodiments is at least 10/1. Thus, the ratio P/B of the fibrous
structure
500 of the present invention is significantiy higher than that of the
structured
papers of the prior art. For illustration, FIGs. 45 and 46 show
photomicrographs
of several exemplary embodiments of the structured paper produced by the
present assignee and generally described, for example, in commonly assigned
US patent 4,637,859. In FIG. 47, which generally outlines a fragment of the
prior
art fibrous structure shown in FIG. 46, a relatively low-density pillow region
is
1 o designated as 640, and a relatively high-density network area is
designated as
610. The pillow 640 of the prior art structure, schematically shown in FIG.
47,
has a perimeter P1 and a base Bi. The ratio P1/B1 is about 4/3, which is
significantly lower than the ratio P/B of the fibrous structure 500 of the
present
invention. It is to be understood that the foregoing ratios may be had in the
fibrous structure of the present invention, even if ifs fibrous pillows 540
comprise
only the fibrous dome portions 530. As has been pointed above, in some
embodiments, at least some of the fibrous pillows 540 might not have the
cantilever portions 549.
The fibrous structure of the present invention can comprise a laminated
structure. FIGs. 43 and 44 show two prophetic embodiments of the laminated
fibrous structure 550 of the present invention, each embodiment comprising two
laminae 500a and 500b. In FIG. 42, the two individual laminae 500a, 500b are
joined such that their respective pillows 540 having fibrous cantilever
portions
549 face one another. It is believed that the present invention allows one to
form
plies so structured that they could be joined together.by using their
respective
fibrous cantilever portions, as schematically shown In FIG. 43. The plies so
joined would have a limited movability relative to one another, primarily in
lateral
directions, without tearing of either one of the plies or separation thereof.
In the laminated paper structures of the prior art, laminae are rigidly joined
so together (usually, by an adhesive or mechanically, or by a combination
thereof)
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CA 02588743 2007-05-29
such that during the use of the laminated structure, the relative movement of
the
individual sheets forming the laminated structure is not possible without
tearing
or separation of the individual sheet. Therefore, during the use, when the
laminated structure is naturally subjected to bending, rumpling, creasing, and
so
on, the rigid connection of the individual sheets comprising the laminates of
the
prior art affects the flexibility of these laminates. Otherwise, the integrity
of one
or both of the sheets comprPsing the laminated structure, or their connection,
may
be compromised. Not intending to be limited by theory, the applicant believes
that the resistance to rumpling (which may include both bending and buckling)
of
to one or both of the laminae affects the flexibility of the laminated
structures of the
prior art.
In contrast with the prior art, the individual sheets 500a, 500b of the
laminated structure 550 shown in FIG. 43 are believed to be able to move
relative one another during the use of the laminated structure by a consumer,
without tearing of either the sheets 500a, 500b, or separation thereof, The
ability
of the individual sheets 500a, 500b which form the laminated structure 550 to
move relative one another is accomplished by providing a non-rigid, flexible
connection between the sheets, due to a highly flexible nature of the pillows
540
and their fibrous cantilever portions 549. In FIG. 43, the sheets 500a, 500b
are
2o believed to be able to move relative each other, primarily in lateral
directions. In
the sheet wherein the first region 510 Is substantially continuous, the
integrity of
the first region 510, which most typically provides strength in the fibrous
structure, is not affected by the flexibility of the pillows 540 and their
fibrous
cantilever portions 549. At the same time, since the respective first regions
510
of the individual Iaminae 500a, 500b are not directly attached to one another,
when the laminated structure as a whole is deformed, the possible inequality
in
deformation of the individual laminae is compensated by their lateral movement
relative one another. Thus, the movable connection between the individual
sheets 500a, 500b minimizes potential excessive tension and/or compression of
3o the laminae 500a, 500b.
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CA 02588743 2007-05-29
The disclosure of commonly assigned US patent application titled
"Laminated Fibrous Structure and Method Of Manufacturing Same" (Paul D.
Trokhan), Serial Number 08/934,406, filed on Sept. 19, 1997, allowed July 03,
2000, issue fee paid on July 20, 2000, Batch No. 092, is incorporated herein
by
s reference. This application teaches a laminated fibrous structure in which
laminae are able to move relative one another without tearing or separation of
any one of the laminae, during its use. The laminae may be movably joined by a
bonding material, by mechanically engaging upstanding fibers created on the
interfacing surfaces of the laminae, or by a combination thereof.
in FIG. 44, the individual iaminae 500a, 500b are joined such that their
respective pillows 540 having the fibrous cantiiever portions 549 are disposed
on
the outside of the laminated structure 550. It is believed that such a
structure
can provide enhanced absorbency characteristics of the resultant laminated
structure, by increasing the outside surface area of the laminated structure
and
by exposing on the outside the pockets 560 formed by adjacent fibrous domes
530 and the fibrous cantilever portions 549.
It is to be understood that an embodiment (not shown) of the laminated
structure 550 is possible in which the pillows side of one of the individuai
laminae
is joined to the side opposite to the pillows side of the other laminae. It is
also to
2o be understood that the laminated structure 550 comprising two laminae is
merely
an illustrative example, and the laminated structure 550 comprising more than
two laminae (not shown) is contemplated by the present invention.
Process For Makina Fibrous Structure
With reference to FIG. 42, one exemplary embodiment of the process for
producing the frbrous structure 500 of the present invention comprises the
following steps. First, a plurality of fibers 501 is provided and is deposited
on the
deflection member 10 of the present invention.
The present invention contemplates the use of a variety of fibers, such as,
for example, papermaking cellulosic fibers, synthetic fibers, or any other
suitable
CA 02588743 2007-05-29
fibers, and any combination thereof. Papermaldng fibers useful in the present
invention include celluiosic fibers commonly known as wood pulp fbers. Fibers
derived from soft woods (gymnosperms or coniferous trees) and hard woods
(anglosperms or deciduous trees) are contemplated for use in this invention.
The
particular species of tree from which the fibers are derived Is immaterial.
The
hardwood and softwood fibers can be blended, or alternatively, can be
deposited
in layers to provide a stratif<ed web. U.S. Pat. No. 4,300,981 issued Nov. 17,
1981 to Carstens and U.S. Pat. No. 3,994,771 issued Nov. 30, 1976 to Morgan
et al. are incorporated herein by reference for the purpose of disclosing
layering
1 o- of hardwood and softwood fibers.
The wood pulp fibers can be produced from the native wood by any
convenient pulping process. Chemical processes such as sulfite, sulfate
(including the Kraft) and soda processes are suitable. Mechanical processes
such as thermomechanical (or Asplund) processes are also suitable. In
addition,
i5 the various semi-chemical and chemi-mechanical processes can be used.
Bleached as well as unbleached fibers are contemplated for use. When the
fibrous web of this invention is intended for use in absorbent products such
as
paper towels, bleached northern softwood Kraft pulp fibers may be used. Wood
pulps useful herein include chemical pulps such as Kraft, sulfite and sulfate
pulps
2o as well as mechanical puips including for , example, ground wood,
thermomechanical pulps and Chemi-ThermoMechanical Pulp (CTMP). Pulps
derived from both deciduous and coniferous trees can be used.
In addition to the various wood pulp fibers, other cellulosic fibers such as
cotton linters, rayon, and bagasse can be used in this invention. Synthetic
fibers,
25 such as polymeric fibers, can also be used. Elastomeric polymers,
polypropylene, polyethylene, polyester, polyolefin, and nylon, can be used.
The
polymeric fibers can be produced by spunbond processes, meltblown processes,
and other suitable methods known in the art. It is believed that thin, long,
and
continuous fibers produces by spunbond and meltblown processes may be
so beneficially used In the fibrous structure of the present Invention,
because such
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CA 02588743 2007-05-29
fibers are believed to be easily deflectable into the pockets of the
deflection
member of the present invention.
The paper fumish can comprise a variety of additives, including but not
limited to fiber binder materials, such as wet strength binder materials, dry
strength binder materials, and chemical softening compositions. Suitable wet
strength binders inciude, but are not limited to, materials such as polyamide-
epichlorohydrin resins sold under the trade name of KYMENEM 557H by
Hercules Inc., Wilmington, Del. Suitable temporary wet strength binders
include
but are not limited to synthetic polyacrylates. A suitable temporary wet
strength
io binder is PARFZTm 750 marketed by American Cyanamid of Stanford, Conn.
Suitable dry strength binders include materials such as carboxymethyl
cellulose
and cationic polymers such as ACCO'M 711. The CYPRO/ACCO family of dry
strength materials are available from CYTEC of Kalamazoo, Mich.
The paper fumish can comprise a debonding agent to inhibit formation of
some fiber to fiber bonds as the web is dried. The debonding agent, in
combination with the energy provided to the web by the dry creping process,
results in a portion of the web being debulked. In one embodiment, the
debonding agent can be applied to fibers forming an intermediate fiber layer
positioned between two or more layers. The intermediate layer acts as a
2o debonding layer between outer layers of fibers. The creping energy can
therefore debulk a portion of the web along the debonding layer. Suitable
debonding agents include chemical softening compositions such as those
disclosed in U.S. Pat. No. 5,279,767 issued Jan. 18, 1994 to Phan et al., the
disclosure of which is incorporated herein by reference Suitable biodegradable
chemical softening compositioris are disclosed in U.S. Pat. No. 5,312,522
issued
May 17, 1994 to Phan et al. U.S. Pat. Nos. 5,279,767 and 5,312,522, the
disclosures of which are incorporated herein by reference. Such chemical
softening compositions can be used as debonding agents for inhibiting fiber to
fiber bonding in one or more layers of the fibers maldng up the web. One
3o suitable softener for providing debonding of fibers in one or more layers
of fibers
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CA 02588743 2007-05-29
forming the web 20 is a papermaking additive comprising DiEster Di (Touch
Hardened) Tallow Dimethyl Ammonium Chloride. A suitable softener is
ADOGEN brand papermaking additive available from Witco Company of
Greenwich, Conn.
The embryonic web can be typically prepared from an aqueous dispersion
of papermaldng fibers, though dispersions in liquids other than water can be
used. The fibers are dispersed in the carrier liquid to have a consistency of
from
about 0.1 to about 0.3 percent. Altematively, and without being limited by
theory,
it is believed that the present invention is applicable to moist forming
operations
fo where the fibers are dispersed in a carrier liquid to have a consistency
less than
about 50 percent. In yet another altemative embodiment, and without being
limited by theory, it is believed that the present invention is also
applicable to
airlaid structures, including air-laid webs comprising pulp fibers, synthetic
fibers,
and mixtures thereof.
Conventional papermaking fibers can be used and the aqueous dispersion
can be formed in conventional ways. Conventional papermaking equipment and
processes can be used to form the embryonic web on the Fourdrinier wire. The
association of the embryonic web with the deflection member can be
accomplished by simple transfer of the web between two moving endless belts
2o as assisted by differential fluid pressure. The fibers may be deflected
into the
deflection member 10 by the application of differential fluid pressure induced
by
an applied vacuum. Any technique, such as the use of a Yankee drum dryer,
can be used to dry the intermediate web. Foreshortening can be accomplished
by any conventional technique such as creping.
The plurality of fibers can also be supplied in the form of a moistened
fibrous web (not shown), which should preferably be in a condition In which
portions of the web could be effectively deflected into the deflection
conduits of
the deflection member and the void spaces formed between the suspended
portions and the X-Y plane.
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CA 02588743 2007-05-29
In FIG. 42, the embryonic web comprising fibers 501 is transferred from a
forming wire to the deflection member 10 by a vacuum pick-up shoe 18a.
Aiternatively or additionally, a plurality of fibers, or fibrous slurry, can
be
deposited to the deflection member 10 directly (not shown) from a headbox or
otherwise. The deflection member 10 in the form of an endless belt travels
about
rolls 19a, 19b, 19k, 19c, 19d, 19e, and 19f in the direction schematically
indicated by the directional arrow "B."
Then, a portion of the fibers 501 is deflected into the deflection portion of
the deflection member 10 such as to cause some of the deflected fibers or
lo portions thereof to be disposed within the void spaces formed by the
suspended
portions 49 of the deflection member 10. Depending on the process,
mechanical, as well as fluid pressure differential, aione or in combination,
can be
utilized to deflect a portion of the fibers 501 into the deflection conduits
of the
deflection member. For example, in a through-air drying process shown in FIG.
42, a vacuum apparatus 18b, applies a fluid pressure differential to the
embryonic web disposed on the deflection member 10, thereby deflecting fibers
into the deflection conduits of the deflection member 10. The process of
deflection may be continued as another vacuum apparatus 18c applies additional
vacuum pressure to even further deflect the fibers into the deflection
conduits of
2o the deflection member 10. According to the present invention, a portion of
the
deflected fibers is disposed in the void spaces formed between the suspended
portions 49 of the framework 20 and the plane formed by its backside 22, or
the
reinforcing element 50, as described above.
The step of deflecting the fibers into the deflection conduits of the
deflection member 10 of the present invention may be beneficially accomplished
by using a process disclosed in commoniy assigned US patent 5,893,965, issued
in the name of Trokhan et al. on April 13, 1999, the disclosure of which is
incorporated herein by reference. According to this process, a web disposed on
the deflection member is overlaid with a fiexible sheet of material such that
the
web is disposed intermediate the sheet of material and the deflection member,
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CA 02588743 2007-05-29
as schematically shown in FIG. 54. The sheet of material has an air
permeability
less than that of the deflection member. In one embodiment, the sheet of
material is air-impermeable. An application of a fluid pressure differential
to the
sheet of material causes deflection of at least a portion of the sheet of
material
towards the deflection member and thus deflection of at least a portion of the
web into the conduits of the papermaking belt.
It is believed that this process can be especiaily beneficial if used with the
deflection member 10 of the present invention, having void spaces formed by
the
suspended portions. The process of the present invention for maldng the
fibrous
lo structure 500, particularly when used with the fluid-impermeable flexible
sheet, or
the sheet of material having relatively low air-permeability, is believed to
allow
one to apply a high deflection pressure without creating pinholes in the
fibrous
structure being constructed. The pinholes may result when a certain amount of
the fibers pass through the deflection member - under the application of a
fluid
pressure differential. The higher the pressure the higher the risk that some
fibers
separate from the fibrous structure and pass through the deflection member,
thereby creating pinholes in the fibrous structure. The fluid-impermeable
sheet
prevents such an occurrence. At the same time, high deflection pressure will
encourage the fibers to better deflect into the deflection conduits and the
void
spaces of the deflection member 10, as schematically shown in FIG. 54, in
which
the sheet of the flexible material overlaying the plurality of fibers is
designated by
a reference numeral 600.
Finally, a partly-formed fibrous structure associated with the deflection
member 10 can be separated from the deflection member, to form the fibrous
structure 500 of the present invention.
The process may further comprise a step of impressing the deflection
member 10 having the fibers therein against a pressing surface, such as, for
example, a surface of a Yankee drying drum 28, thereby densifying the first
region 510. In some instances, those fibers that are disposed within the voids
so formed between the reinforcing element 50 and the suspended portions 49 can
CA 02588743 2007-05-29
also be at least partially densified. In FIG. 42, the step of impressing the
web
against the Yankee drying drum is performed by using the pressure roll 19k.
This also typically includes a step of drying the fibrous structure. As the
deflection member 10 is impressed into the web, the suspended portions 49 can
densify the corresponding portions of the web, thereby encouraging creation of
the fibrous cantilever portions 59 of the finished product. Then, based on the
density, the fibrous structure may comprise three pluralities of micro-
regions: the
first plurality of micro-regions having a relatively high density, the second
plurality
of micro-regions comprising fibrous domes extending from the first plurality
of
1 o micro-regions and having a relatively low density, and a third plurality
of micro-
regions comprising fibrous cantilever portions laterally extending from the
domes
and having an intermediate density relative to the relatively high density of
the
first plurality of micro-regions and the relatively low density of the second
plurality
of micro-regions.
Examale
The deflection member 10 of the present invention was produced with a
first layer 30 comprising nine discrete deflection conduits per square inch,
and a
second layer 40 comprising forty-one deflection conduits per square inch
("41/9"
pattern). The conduits' geometry was a diamond with filleted vertices. The
cumulative projected open area (ER) of the deflection conduits 35 of the first
layer 30 was 0.0756 square inches, and the cumulative projected open area of
the second layer's deflection conduits was 0.0161 square inches. The first and
second specific resulting open areas R1 and R2 (I. e., ratios of the
cumulative
projected open area of a given layer to a given surface area) was computed to
be: R1 = 68% for the first layer, and R2 = 66% for the second layer. The
thickness of each layer was 0.020 inches. The two-layer structure was bonded
to a dual-tayer 48 X 55 mesh belt known commercially as a stacked, warped,
dual-layer belt, which is produced by the Appleton Wire Division of Albany
International of Appleton, WI.
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CA 02588743 2007-05-29
Paper handsheets were produced using the "41/9" deflection member 10
as described above, according to a modified TAPPI handsheet method. The
handsheets comprised 80% NSK (Northem Softwood Kraft), 18% CTMP (Chemi-
Thermo Mechanical Pulp), and 2% Eucalyptus Pulps. The pulp slurry was
disintegrated per TAPPI standards and diluted to yield a conditioned basis
weight
of 13 pounds per 3000 square feet (at 2 hours at 70 F and 50% RH). The
handsheet was directly formed, vacuumed, and dried on the 41/9 deflection
member 10 of the present invention. Once dried, the handsheet was peeled off
of the defiection member 10. Several photomicrographs reproduced herein in
1o FIGs. 32-41 show cross-sectional configurations of these handsheets.
87
