Note: Descriptions are shown in the official language in which they were submitted.
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NON-WOVEN STRUCTURES AND METHODS OF MAKING THE SAME
FIELD OF THE INVENTION
The present invention relates generally to layered, co.mposite materials. More
specifically, the present invention relates to layered, composite materials
exhibiting
advantageous lamination strength, and one or more additional beneficial
properties
such as drapeability, loftiness, abrasion resistance, liquid absorbency,
softness, and/or
visual appeal.
BACKGROUND
Non-woven materials are used widely in a variety of commercially-available
personal care products including, for example, wipes and feminine hygiene
products,
such as napkins, liners, and tampons, and the like. In many of these
applications, it is
desirable for the non-woven materials to have sufficient strength such that
the material
maintains its integrity in use. For example, it is often desirable in certain
uses to reduce
delamination that might otherwise occur between various material layers of the
nonwoven.
Applicants have further recognized that it is also desirable for such
materials to
have other beneficial properties in combination with relatively high
strength/integrity.
For example, it would be desirable to have such materials that are abrasion
resistant
and/or also "drapeable" so as to provide comfort to the user. As used herein,
the term
"drapeable" refers to the tendency of a material to hang in a substantially
vertical
-fashion due to gravity when held in a cantilevered manner from one end of the
material.
Materials exhibiting high drapeability tend to conform to the shape of an
abutting
surface, such as against a user's skin, thereby tending to enhance comfort to
the user of
a product comprising the high-drape material. Applicants have further
recognized that
'it is also desirable in certain applications for the relatively strong
nonwovens to be
bulky (i.e., low density), and/or to have patterns therein.
Accordingly, applicants have recognized the need for non-woven materials that
exhibit the highly desirable, and unique combination of high lamination
strength/high-
integrity and either or both of high drapeability properties or low-density,
for use in any
of a variety of articles. In addition, applicants have recognized the need for
unique
methods of producing such materials, including, but not necessarily limited
to, methods
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of producing such materials via the hydroentanglement of nonwovens and novel
patterning methods.
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SUMMARY OF INVENTION
Applicants have met the need identified above by producing a fibrous,
composite
structure having the unique and desirable combination of relatively high
lamination
strength in combination with high drapeability and/or low density properties.
According to one aspect, the present invention is directed to a layered,
composite
material comprising a fibrous, fluid-permeable anchoring layer and a fibrous
layer
comprising fibers entangled about said anchoring layer, said composite
material having
a laminat'ion strength of greater than about 20 grams and a drapeability of
greater than
about 4. gsmlg
According to another aspect, the present invention is directed a layered,
composite material comprising a fibrous, fluid-permeable anchoring layer and a
fibrous
layer comprising fibers entangled.about said anchoring layer, said coniposite
material
having a lamination strength of greater than about 20 grams and a density less
than
about 0.15 grams per cubic centimeter (g/cc).
The composite materials of the present invention may be used to great benefit
in
a wide variety of personal care articles. Accordingly, in another embodiment,
the
present -invention is directed to a personal care article comprising a
composite material
of the present invention.
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BRIEF DESCRIPTION OF THE DRAWINGS
Examples of embodiments of the present invention will now be described with
reference to the drawings, in which:
Figure:l is a cross-sectional view of an embodiment of a layered, composite
material of the invention described herein;
Figure 2 is a cross-sectional view of another embodiment of a layered,
composite material of the invention described herein;
Figure 3 is a top, plan view of another embodiment of a layered, composite
material of the invention described herein, showing additional features
thereof;.
Figure 4 is a cross-sectional view of the layered, composite material of
Figure
3, taken through line 3-3';
Figure 5 is a cross-sectional view depicting the formation of a layered,
composite material according to a process consistent with embodiments of the
invention described herein;
Figure 6 is a cross-sectional view depicting the formation of a layered,
composite material according to another process consistent with embodiments of
the
invention described herein;
Figure 7 is a perspective view of a mask*that may be used to form a layered
composite material consistent with embodiments of the invention described
herein;
Figure 8 is.a,plan view of a length of patterned, layered composite material
810
consistent with embodiments of the invention described herein; and
Figure 9 is a cross-sectional view depicting the patterning of a layered,
composite material according to embodiments of the invention described herein.
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DESCRIPTION OF PREFERRED EMBODIMENTS
According to certain embodiments, the present invention is directed to
layered,
composite materials comprising a fibrous, fluid permeable anchoring layer and
a
fibrous layer having fibers entangled about the anchoring layer, which
composite
materials exhibit a unique combination of relatively high lamination strength
in
conjunction in one or more relatively high drapeability, and/or low density
(high
bulkiness or "bulk") as corripared to conventional non-woven structures. Such
unique
materials are, in certain embodiments, also beneficially abrasion resistant,
durable, soft,
comfortable, and/or absorbent. In certain embodiments, such materials are
further
useful for providing various other benefits, including fluid absorption or
fluid isolation,
cleansing, and exfoliation capability in a variety of products.
In particular, applicants have measured the lamination strength of composite
materials according to certain embodiments of the present invention in accord
with the
"Lamination St'rength Test" described in detail below. As will be understood
by those
of skill in the art, a resulting higher Lamination Strength Value indicates a
relatively
greater ability for the anchoring layer and fibrous layer having fibers
entangled about
the anchoring layer of the composite material to resist de-bonding.from one
another as
a result of applied force and a lower Lamination Strength Value indicates a
relatively
lesser ability for the two layers to resist de-bonding upon applied force. Iri
addition,
applicants have recognized that a relatively high lamination strength tends to
correlate
to the consumer-desirable "durability" of the layered, composite material.
According
to certain embodiments, the present composite material'exhibit a Lamination
Strength
Value that is about 20 grams or more, more preferably about 50 grams or more,
and
even more preferably from about 100 grams or more.
Applicants have also measured the drapeablility of the present structures via
the
"Drapeability Test", described in detail below and understood by those of
skill in the art.
Applicants have recognized that in certain embodiments the present structures
exhibit
not only desirably high lamination strength, as described above, but also
exhibit
relatively high drapeability in combination therewith. In particular,
according to
certain embodiments, the present structures exhibit a drapeability (basis
weight/MCB)
that is greater than about 4 grams per square meter per gram (gsm/g) or
greater,
preferably greater than about 6 gsm/g, and even more preferably from about 8
gsm/g to
about 16 gsm/g.
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Applicants have also measured the density of the composite materials of
certain,
preferred embodiments of the ptesent invention via the "Density Test,"
described in
detail below and understood by those of skill in the art. Applicants. have
recognized
that in certain embodiments the present structures exhibit not only desirably
high
lamination strength, as described above, but also exhibit relatively low
density in
combination therewith. According to certain embodiments, the present
structures
exhibit a density that is about 0.15 g/cc or less, more preferably about 0.12
g/cc or less,
and even more preferably from about *0.12 g/cc to about 0.03 g/cc.
According to certain embodiments, applicants have recognized that in addition
to relatively high lamination strength in combination with relatively high
drapeability
and/or relatively low density, the composite materials of the present
invention further
comprise one or more properties selected from relatively high absorbent
capacity,
relatively high tensile strength, desirable thickness, and combinations of two
or more
thereof. For example, in certain embodiments of the invention, the layered,
composite
material has an absorbent capacity that is greater than about 3 g/g,
preferably greater
than about 4 g/g, and more preferably about 5 g/g. In certain embodiments, the
composite material has a tensile strength in the machine direction (measured
via the
"Tensile Strength Test," described in detail below and understood by those of
skill in the
art) of about 10 N/5cm or more, preferably about 15 N/5cm or more, more
preferably
about 20 N/5cm or more. The thickness of the composite materials of the
present
invention may be optimized for use in any of a wide range of articles and any
suitable/desired thickness for a particular article may be used. In certain
preferred
embodiments, the composite materials of the present invention have a thickness
of less
than about 10mm, preferably less than about 5mm, more preferably less than
about
2mm, and even more preferably from about 0.3mm to about 2mm.
Figure 1 is a cross-sectional view depicting an embodiment of a layered,
composite material 100 consistent with embodiments of the invention described
herein.
The layered, composite mater=ial 100 comprises a fibrous, fluid-permeable
anchoring
layer 110 and a fibrous layer 122 having fibers 120, at least a portion of
which are
entangled about anchoring layer 110.
The fluid-permeable, anchoring layer 110 may comprise any suitable fibrous
material that is permeable to fluids. By permeable to fluids, it is meant that
gases or
liquids, such as water (and the like) may be urged through a cross-section of
the fluid-
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permeable, anchoring layer 11U, i.e, from an outer surface 112 of the fluid-
permeable,
anchoring layer 110, through the fluid-permeable, anchoring layer 110 to
emerge from
an inner surface 114 of the fluid-permeable, anchoring layer 110. In certain
preferred
embodiments, to facilitate the movement of fluid through the fluid-permeable,
anchoring layer 110, the fluid-permeable, anchoring layer 110 comprises a
network of
interconnected pores 116. In certain preferred embodiments, the anchoring
layer has a
percent open area of about 25% or more. Preferably, the fluid-permeable,
anchoring
layer 110 is also generally resistant to dissolution and mechanical
degradation that
would be caused by urging high pressure fluids such as water or air
therethrough.
In certain embodiments, the fluid-perrneable, anchoring layer 110 is
relatively
thin, for example, having thickness of less than about 2000 microns, more
preferably
from about 3 to about 2000 microns. The fluid-permeable, anchoring layer 110
may be
of any 'suitable basis weight. In certain preferred embodiments, the anchoring
layer has
a basis weight of from about 5 gsm to about 20gsm, and more preferably, about
5 gsm
to about 15 gsm. Furthermore, the fluid-permeable, anchoring layer 110 is
preferably
mechanically integrated such that it has a tensile strength of at least about
5 N/5cm.
Additionally, it is desirable that the fluid-permeable anchoring layer is
preferably
selected to be relatively flexible (i.e. tends not to be stiff) which
applicants have
recognized tends to benefit in the drapeability associated with a material
incorporating
the anchoring layer.
In preferred embodiments, the fluid-permeable, anchoring layer 110 comprises
or consists essentially of a polymeric material, such as a bonded, fibrous
material,
including a spun-bond or thermobonded, such as a through-air bonded, material,
and
the like. By "through air bond," it is meant fibers that have been oriented by
various
means such as carding and have been bonded together by passing a heated stream
of air
therethrough. By "spun bond" it is meant fibers that are melt spun by
extruding molten
thermoplastic polymer as fibers from a plurality of fine, usually circular,
capillaries of a
.spinneret with the diameter of the extruded fibers then being rapidly reduced
by
drawing and then quenching the fibers. Spun-bond fibers are usually continuous
fibers.
Suitable spun-bonded materials are formed from fibers having a diameter from
about 3
microns to about 20 microns and having a fiber length greater than about
200mm. The
fibers of the anchoring layer may include such materials as polyolefins such
as
polypropylene, polyethylene, bicomponent fibers formed from polypropylene,
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polyethylene, or combinations-thereof. The spun bond fibers may be
subsequently
compressed to provide increased strength or reduced thickness. In a preferred
embodiment, the fluid-permeable, anchoring layer 110 comprises or consists
essentially
of a spun bond material.
The outer surface 112 of the fluid-permeable, anchoring layer 110 is generally
an abrasion resistant surface. By "abrasion resistant" it is meant that the
outer surface
112 generally resists degradation from resilient objects, e.g., a hand or
other body
surfaces being passed across the outer surface 112.
The layered, composite material 100 comprises fibers 120 at least a portion of
which are entangled about the fluid-permeable, anchoring layer 110. .The
fibers are
preferably associated with a fibrous layer 122. The fibers entangled about the
fluid-
permeable, anchoring layer 110 preferably includes a plurality of fibers or
filaments
that are associated with one another and with the fluid-permeable, anchoring
layer 110
such as by entanglement. As such, the fluid-permeable, anchoring layer 110 in
effect
serves as a "skeleton" for the layered, composite material 100.
The entanglement of the fibers about the fluid-permeable, anchoring layer 110
generally results.in a bonding between the fibrous layer 122 and the fluid-
permeable,
anchoring layer 110 about an interface 124. While the interface 124 is
depicted
essentially a line in Figure 1, the interface 124 generally has a thickness
associated
therewith. The nature of the interface 124 is that of-fibers twisted, knotted,
tied or
otherwise entangled about the. fluid-permeable, anchoring layer 110.
In certain preferred embodiments, the anchoring layer 110 and the fibers of
the
fibrous layer 122 entangled about the anchoring layer 110 are substantially
free of
bonding formed from melting the fibers and/or anchoring layer 110 and/or
bonding
formed using chemical adhesives. As used herein the term `substantially free
of
bonding formed from melting the fibers and/or anchoring layer 110 and/or
bonding
formed using chemical adhesives" means a material wherein less than 10% by
weight
of the fibers of fibrous layer 122 bonded to anchoring layer 110 are so bonded
via
melting or chemical adhesives. Preferably, a material substantially free of
bonding
formed from melting the fibers and/or anchoring layer 110 and/or bonding
formed
using chemical adhesives comprises less than 5%, and more preferably no fibers
of
fibrous layer 112, that are bonded to the anchoring layer 110 via melting or
chemical
adhesives. While applicants do not wish to be bound by or to any theory of
operation,
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it is believed that by restricting the bonding of the fibers of the fibrous
layer 122 and
the fluid-permeable, anchoring layer 110 to physical entanglement rather than
melt
bonding or chemical adhesives, the resulting layered, cornposite material 100
tends to
be more drapeable.
Any of a wide variety of various fibers may be selected for use in the fibrous
layer 122. Examples of suitable fibers include those derived from cellulose,
polyester,
rayon, polyolefin, polyvinyl alcohol, polyamide or other synthetic fibers,
combinations
of two or more thereof, and the like. Certain preferred'fibers include
cellulose,
polyester, rayon, or polyolefin, alone or in combinations of two or more
thereof.
Examples of commercially available suitable fibers include "Galaxy" rayon
fibers
commercially available from Kelheim Fibers, Kelheim, Germany or Tencel lyocell
fibers commercially available from Lenzing AG of Lenzing, Austria.
In certain embodiments of the invention, the fibers include cellulose such as,
for
example, wood'pulp. In one embodiment of the invention, the fibrous layer 122
includes from about 0% to about 100% pulp, more preferably from about 5% to
about
50%.
In certain preferred embodiments of the invention the wood pulp has a reduced
capacity for hydrogen bonding. Wood pulp having reduced capacity for hydrogen
bonding may be formed by a process that includes the step of treating a liquid
suspension of pulp at a temperature of from 15 C. to about 60 C with an
aqueous
alkali metal salt solution having an alkali metal salt concentration of from
about 2
weight percent to about 25 weight percent of said solution for a period of
time ranging
from about 5 minutes to about 60 minutes. Reagents suitable for caustic
treatment
include, but are not limited to, alkali metal hydroxides, such as sodium
hydroxide,
potassium hydroxide, calcium hydroxide, and rubidium hydroxide, lithium
hydroxides,
and benzyltrimethylammonium hydroxides. Sodium hydroxide is a particularly
preferred reagent for use in the caustic treatment to produce cellulosic
fibers suitable
-for forming the superabsorbent cellulosic fibers in accordance with the
present
invention. The pulp preferably is treated with an aqueous solution containing
from
about 4 to about 30% by weight sodium hydroxide, (or any other suitable
caustic
material), more preferably from about 6 to about 20%, and most preferably from
about
12 to about 16% by weight, based on the weight of the solution. Caustic
treatment may
be performed during or after bleaching, purification, and drying. Preferably,
the caustic
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treatment is carried out during the bleaching and/or drying process. Pulp so
produced
is sometimes referred to as "caustic extractive pulp" or "mercerized pulp."
Commercially available caustic extractive pulp suitable for use in the present
invention
include, for example, Porosanier-J-HP, available from Rayonier Performance
Fibers
Division (Jesup, Ga.), Buckeye's HPZ, available from Buckeye Technologies
(Perry,
Fla.), and TRUCELL available from Weyerhaeuser company (Federal Way, Wash.).
. In another preferred embodiment of the invention, the pulp having reduced
capacity for hydrogen bonding is crosslinked. By "crosslinked", refers to
cellulosic
fibers that have primarily intrafiber chemical crosslink bonds. That is, the
crosslink
bonds are primarily between cellulose molecules of a single fiber, rather than
between
cellulose molecules of separate fibers.
The crosslinked fibers may be formed by various processes, such as,.(1) the
process described in U.S. Pat. No. 3,241,553, issued to F. H. Steiger on Mar.
22, 1966,
in which individualized, crosslinked fibers are produced by crosslinking the
fibers in an
aqueous solution containing a crosslinking agent and a catalyst; or (2) the
process
described in U.S. Pat. No. 3,224,926 issued to L. J. Bemardin on Dec. 21,
1965, in
which individualized, crosslinked fibers are produced by impregnating swollen
fibers in
an aqueous solution with crosslinking agent, dewatering and defiberizing the
fibers by
mechanical action, and drying the fibers at elevated temperature to effect
crosslinking
while the fibers are in a substantially individual state; among other known
methods.
Commercially available crosslinked pulp suitable for use in the present
invention
include, for example, Columbus Modified Fiber, grade #CHB416, available from
Weyerhauser Corporation, (Federal Way, Wash.).
In certain embodiments, the layered, composite material 100 is preferably
substantially free of fibers that are woven, knitted, tufted or stitch-
bonding, i.e., the
layered, composite material preferably includes fibrous materials that are
made directly
from fiber rather than yarn.
In addition to fibers, the fibrous layer 122 may comprise various additional
materials well known in the art of the art of the manufacture of non-wovens
for use in
absorbent articles. For example, the fibrous layer 122 may comprise polymers
or other
chemical fiber-finishes or particulate materials such as superabsorbents which
may be
distributed among the fibers used to enhance fluid absorption properties or
pigments or
other light-reflecting agents to promote a particular appearance. The fibrous
layer 122
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is preferably substantially free of chemical.'binders that may otherwise
increase
stiffness or reduce the drapeability of the composite.
The fibrous layer 122 may be homogeneous or heterogeneous in terms of fiber
composition, throughout its thickness. In certain preferred embodiments, the
fibrous
layer 122 comprises a heterogenous mixtiire, for example, comprising cellulose
and
synthetic fibers. In certain other preferred embodiments, fibrous layer 122 is
a
homogenous layer, for example, consisting essentially of cellulose fibers or
essentially
of synthetic fibers.
In certain preferred embodiments of the invention, 50% by weight or more of
the fibers of the fibrous layer 122 are made of fibers having a length to
diameter ratio
greater than about 300. While such fibers may be staple fibers or continuous
filaments,
it is preferred that the fibers are staple fibers. The fibers may be, for
example, cellulose
fibers such as wood pulp or cotton; synthetic fibers such as polyester, rayon,
polyolefin,
polyvinyl alcohol, multi-component (core-sheath) fibers and combinations of
two or
more thereof. The fibers may be may be placed in association with one another
using
and suitable methods including those described in detail below.
The fibrous layer of the present invention may be of any suitable basis
weight.
In certain preferred embodirrients, the fibrous layer 122. may have a basis
weight from
about 20 gsm to about 200 gsm, preferably from about 20 gsm to about 150 gsm.
In, an altemative embodiment, as depicted in Figure 2, the fibrous layer 122
may
itself comprise of a plurality of layers or strata. Figure 2 depicts an
uppermost fibrous
layer 210 and a lower fibrous layer 220. In one embodiment, the uppermost
fibrous
layer 210 comprises of consists essentially of one or more synthetic fibers
sil-ch as
olefinic or polyester or bicomponent fibers; and the lower fibrous layer 220
comprises
or consists essentially of cellulose fibers. Furthermore, while Figure 2
depicts fibrous
layer 122 consisting of only 2 layers, additional layers having various
compositions are
contemplated.
-In addition, while Figures 1 and 2 depict a single fluid-permeable, anchoring
layer 110 one terminal end.of the layered, composite material 100, it is
within the scope
of the invention to include a second fluid-permeable, anchoring layer 110 at
an opposite
terminal end of the layered, composite material 100, thereby creating
a"sandwich '
structure, by which one or more fibrous layers are, en masse, sandwiched
between the
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two fluid permeable anchoring layers. In such a configuration, two separate
abrasion
resistant surfaces are present.
One may tailor the properties of the layered, composite materials based upon
the desired properties. For example, generally to provide lower density and
higher
drapeability one may choose, for example primarily polyester, rayon, and
blends
thereof. If one were interested in providing high absorbent capacity and lower
cost, one
may select primarily wood pulp. In order to balance all of these properties,
the fibrous
layer 122 may itself comprise separate layers of these materials:
In certain embodiments of the invention, the layered, composite material.is-
provided with a visible pattern. Figure 3 is a top plan view. of a layered,
composite
material consistent with embodiments of the invention described herein. The
layered,
composite material 100 includes discrete raised regions 300 surrounded by a
matrix 310
of low regions. Figure 4 is a cross section of Figure 3 taken through section
3-3',
revealing various features thereof. The raised regions 300 and the lower
regions 310
are visibly distinct from one another, e.g., a viewer of average and unaided
eyesight
should be able readily to discern the difference or contrast between the
raised regions
and the lower regions 310 when viewing the layered, composite material 100
from a
distance of 12 inches. In one embodiment of the invention, the raised regions
300
preferably have a height 320 that is from about 0.1mm to about 5mm, more
preferably
from about 0.5mm to about 2mm, and a length or width of at least about 0.5mm,
more
preferably at least about 1mm, and most preferably at least about 3mm.
In one embodiment of the invention, the raised regions 300 are unentangled and
unbonded, i.e., no significant bonding.is evident at an interface 330 between
the fluid-
permeable, anchoring layer 110 and the fibrous layer 122 in the raised region
300. In
this embodiment of the invention, substantial bonding between the fluid-
permeable,
anchoring layer 110 and the fibrous layer 122 exists only within the lower
regions 310,
such as along interface 340. As such, cross sections of entangled regions 360
and
cross sections of unentangled regions 350 (the boundaries of which are shown
in
phantom in Figure 4) are present within the layered, composite material 100.
Figure 4 depicts the layered, composite material 100 having a continuous cross-
section (matrix) of entangled region 360 and a plurality of discrete cross-
sections of
unenetangled regions 350 positioned substantially within the continuous cross-
section
of the entangled region. This configuration is often desirable to proyide
sufficient
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tensile strength to the layered, composite material 100. However, other
configurations
of raised regions and lower regions are also contemplated. For example, the
raised
regions may be arranged along an entire width or length of the layered,
composite
material 100 rather than be arranged as discrete regions 350 surrounded by or
substantially within the lower regions 360. Furthermore, the sense of the
entangled
regions and unentangled regions may be "inverted" as compared to the material
shown
in Figure 3, e.g.., the entangled regions may be positioned substantially
within the
unentangled regions.
In certain preferred embodiments, the layered, composite materials of the
present invention are spun-lace structures. That is, they are materials
derived from a
hydroentanglement or "spun-lace" pirocess, preferably such processes as are
described
herein. Applicants have found that the structures of the present invention
exhibit
excellent abrasion resistance and surprisingly good lamination strength and/or
drapeability, and/ or density as compared to conventional fibrous, non-woven
structures, especially conventional spun-lace materials. Such novel and
surprising
combination of properties provides significant advantage to the instant
structures in a
variety of uses including, but not limited to, personal care articles such as
feminine
hygiene products and wipes.
In one embodiment of the invention, the layered, composite material is used as
a
component of a sanitary pad such as a sanitary napkin or pantiliner. For
example, the
layered, composite material may be a topsheet or an integrated
topsheet/absorbent core
layer of a pantiliner or sanitary napkin.
In certain preferred embodiments, the layered, composite material is such that
the fluid-perrneable, anchoring layer 110 is capable of being oriented towards
the body
of a user, and thus the fluid-permeable, anchoring layer 110 is part of a body-
faceable
surface of the sanitary pad. In certain preferred embodiments, the layered,
composite
inaterial serves as an integrated topsheet/absorbent core layer of a sanitary
napkin or
pantiliner. Such an integrated topsheetlabsorbent core layer comprising a
layered,
composite material of the present invention would be advantageous in that the
integrated cover provides enhanced abrasion resistance, softness, absorbency,
and
drapeability, all of which contribute to enhancing comfort of the wearer.
In one embodiment of the invention, the fibrous, non-woven material is used as
a component of a wipe, e.g., a "baby wipe," a personal care/cosmetic wipe or
wipe (wet
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or dry) useful for personal cleansing, or a wipe for the cleansing of
inanimate surfaces.
Layered, composite materials of the present invention may be used a single
layer wipe
or as one or more layers in a multi-layered wipe. Preferably, the abrasion
resistant
surface(s) of the layered, composite materials are positioned on the extemal
surface(s)
of the wipe so as to contact the users skin. A wipe material comprising a
layered,
composite materials of the present invention would be advantageous in that the
wipe
has botli good abrasion resistance (and therefore durability) as well as
softness,
compressibility and absorbency.
METHODS OF THE PRESENT INVENTION
Layered, composite materials of the present invention may be produced via any
of a variety of novel methods discovered by applicants. For example, according
to
certain embodiments, the structures may be produced via a method including
urging a
stream of fluid into contact with a layered structure, wherein the layered
structure
includes fibers and a fluid-permeable, anchoring layer, wherein the fluid-
permeable,
anchoring layer is positioned to at least partially shield the layer of fibers
from the
stream of fluid.
Figure 5 illustrates one embodiment of a method of conducting a
hydroentangling step according to the present invention. The hydroentangling
step
comprises providing'a layer of fibers 520, which is laid onto a screen 590
(e.g. a metal
or plastic screen), which in turn rests upon a movable conveyer (not shown).
The term
"layer" it is meant an assembly of fibers that has a thickness that is
substaritially less in
dimension as compared with both a length and a width 205 of said assembly. For
example, the layer 520 may have a thickness that is less than. about 10% of
the width
such as less than about 2% of the width. In a preferred embodiment, the thin
layer 200
of fibers is substantially planar and less than about 20 mm in thickness,
preferably less
than about 5min. The thin layer of fibers has a composition.and properties as
described
above with reference to fibrous layer 122 described above and depicted in
Figures 1
and 2.
The layer of fibers 520'may be unbonded to one another. By "unbonded," it is
meant that the fibers in the thin layer 520 are loosely associated with one
another, and
the layer has a very low tensile strength, such as less than about 5 N/5cm: In
an
14
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alternative embodiment, the layer of fibers '520 are bonded to one another,
e.g. loosely
bonded, prior to spun-lacing.
Fluid-permeable, anchoring layer 110 is positioned atop the -layer of fibers
520.
The layer of fibers 520 and the fluid-permeable, anchoring layer 110 thereby
form a
target web 550 to be entangled. In operation, the target web 550 is moved in a
machine direction within the range of jets 530 from which a stream of fluid
508,
preferably a liquid, more preferably water, is urged. It is contemplated that
the layer of
fibers 520 may impact the target 550 in any suitable direction and with any
pressure
suitable to form a stabilized web. Preferably, the stream of fluid 508 are
oriented to
impact the layer in a substantially perpendicular manner and at a pressure of
for
example from about 500 psi to about 5000 psi. As used herein, the term
"substantially
perpendicular" (such as from about 20 degrees to about 0 degrees, preferably
from
about 10 to about 0 degrees, and more preferably from about 5 to about 0
degrees, and
most preferably about 0 degrees).
The target web 550 may be moved in the machine direction before, during,
and/or
after contact with the stream of fluid 508 at any speed suitable for
entangling the target.
[n certain embodiments, the stabilized web 210 is moved in the machine
direction at a
;peed of at least about 10 feet per minute (fpm), such as from about 50 fpm to
about 250
Epm.
Upon completion of the entangling step, the fluid-permeable anchoring layer is
entangled about the layer of fibers, forming a layered composite material of
the present
invention, in a manner as described above and as depicted in the examples
shown in
Figures 1 and 2.
Figure 6 depicts hydroentanglement of a target web similar to that depicted in
Figure 5, except that the stream of fluid 508 is urged through a mask 600 that
moves
relative to the jet 530. The mask 508 may revolve about a series of guides or
rollers
.660 in order to, at various points in time, align different portions of the
mask 600 with
the stream fluid 508.
The mask 600 has a spatially-varying permeability to the stream of fluid 508:
In particular, as shown in Figure 6 and Figure 7 (a perspective view of the
mask 600),
the spatially varying permeability is created by a including a pattern of high
permeability portions 620 and low permeability portions 630. The high
permeability
portions 620 may be, for example, open space (which permits essentially all of
the fluid
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to pass through the high permeability portion 620). Alternatively, high
permeability
portions 620 may comprise a siupporting screen, such as screen 650'shown in
Figure 7
that is sufficient to provide mechanical support to the mask 600, but does not
impede a
significant portion of the flow of the stream of fluid 508. In one embodiment,
the high
permeability portions 620 have an open area of at least about. 50 percent, and
more
preferably at least about 65%.
By contrast, the low permeability portions 630 of the mask 600 typically block
most or preferably all of the stream of fluid 508 urged into'contact therewith
from
contacting the target web 550.
At a first instant in time, when the jet 530 is above a high permeability
portion
620 of the mask, a portion of the target web 550 underneath the jet 530 is
contacted
with the stream of fluid 508 and is thereby entangled. In contrast, at a
second instant in
time, when the jet 530 is above a low permeability portion 630 of the mask, a
portion of
the target web 550 underneath the jet 530 is not contacted (or, alternatively,
minimally
contacted ) with the stream of fluid 508 and is thereby left relatively
unentangled.
Over a time interval (i.e., a full pattem cycle) over which the mask is
allowed to
revolve completely around, the pattern of high permeability portions 620 and
low
permeability portions 630 on the mask 600 are thereby transferred to a length
of the
target web 550, forming a patterned, layered composite material. An example of
a
length 800 of patteirned, layered composite material 810 is shown in Figure 8.
The
process then repeats, generating a series of identical lengths of layered,
composite
material, which may later be separated from one another (e.g., by cutting).
Note that in Figure 8, a pattern of unentangled raised flotivers is shown
against a
uniform flat background. Note that if the low permeability portions 630 of the
mask
800 are not completely open (e.g., comprise a screen - as shown in Figure 7),
then
some of the blocked portions of the screen may be in effect "transferred'
onto the
layered composite material as a minority area of raised background features
850, e.g.,
fine lines or cells; distributed in a majority portion 860 of entangled
regions that
provide tensile to the layered, composite material.
The length 800 of the layered, composite material over which the pattern may
be repeated (i.e., the length of the mask if laid on a flat surface) is
variable and may be,
for example from about 50 cm to about lOm. Note that the boundaries of length
80 are
shown in phantom in Figure 8.
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The mask 800 may be riiade by various methods known in the art. For example,
mask 800 may be made by selectively etching a metal plate. The plate may be
formed
of a flexible sheet of aluminum, stainless steel, or copper, or from a
polymeric material
including plastic or rubber (which may be reinforced), and may have a
thickness of, for
example about 0.05mm to about 0.5mm.
While Figures 6-8 depict one process for creating a visibly patterned,
layered,
composite material, other processes are contemplated. For example, rather than
utilizing a mask that moves relative to the jets, the jets may be selectively
blocked in
certain locations, thus giving rise to lines or stripes of unentangled raised
regions
adjoining or interspersed with entangled low regions.
In yet another embodiment of the invention, a visible pattern is =provided
using a
topographic forming surface. In this embodiment of the invention a stream of
fluid is
urged into contact with a target web that is supported on a topographic
forming surface.
The topographic support member generally includes an arrangement of peaks and
valleys as well as an arrangement of apertures and may be similar to, for
example, the
topographic support members disclosed in U.S patents 5,827,597 and 5,674,587
(both
to James et al.) which are hereby incorporated by reference in their entirety.
The
arrangement of peaks and valleys may be formed by any suitable techniques such
as
mechanical drilling, laser drilling, laser ablation, raster scanning, laser
modulation,
among other techniques.
In embodiments of the present inventive method, a layered structure comprising
a layer of fibers and a fluid permeable anchoring layer are positioned on the
topographic support member. Streams of fluid are directed onto the layered
structure
thereby molding the layered structure to the topographic support member and
entangling the layer of fibers about the fluid permeable anchoring layer.
In one preferred embodiment as depicted in Figure 9, fluid, permeable
'anchoring layer 900 is positioned in direct contact with the topographic
support
member 910 and layer of fibers 920 is positioned on the fluid, permeable
anchoring
layer. ~As such, the layer of fibers 920 at least partially shields the fluid
permeable
anchoring layer from the fluid. The layer of fibers 920 may include various
materials
such as those described above for the fibrous layer 122.
In a further preferred embodiment, the layer of fibers includes cellulose such
as
wood pulp, preferably mercerized or crosslinked pulp as discussed above. In
yet
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another preferred embodiment, the layer of fibers 920 incltides at least two
distinct
layers, such as a layer of synthetic fibers 930 positioned directly on the
fluid, permeable
anchoring layer 900 and a layer of cellulose fibers 940 (e.g. pulp) positioned
directly on
the layer of long fibers 930. In this embcidiment, the stream of fluid 508
sequentially
impacts the layer of cellulose fibers 940, the layer of long fibers 930, the
fluid,
permeable anchoring layer 900, then the topographic support member 910. In
this
embodiment of the invention, the layer of synthetic fibers 930 and the fluid,
permeable
anchoring layer 900 act as barriers, preventing the relatively short cellulose
fibers from
being transported towards drainage apertures 960 formed in the topographic
support
member 910. As a result there is little chance of the short cellulose -fibers
clogging the
drainage apertures 960, which would resiilt in process difficulties.
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EXAMPLES
The following Ex.amples are illustrative of the present invention and are not
intended to be limiting in any manner.
EXAMPLE 1
In each of the following examples, a target web was placed on a$0-mesh metal
screen forming surface, on a rotating cylindrical drum. - The target web
consisted of a
layer of fibrous material and a fluid-permeable anchoring layer. The fluid
permeable
anchoring layer used was a 12gsm layer of spuri-bonded polypropylene,
commercially
available from BBA Fiberweb. The fibrous material was a blend of 70% rayon
fibers
and 30% polyester fibers of varying basis weight. The drum was rotated to move
the
layer of fibers at a linear speed of 100 fpm. The jets were oriented to expel
a stream of
pressurized water to strike the target web perpendicularly to the target web.
The jets
were arranged in a row of jets spaced to a jet density of 30 jets/inch. All
fibrous layers
were subject to an initial stabilization treatment in which water was urged
though each
of a number of 0.005-inch diameter jets at 600 psi to loosely bond the fibers
prior to
entangling with the spun-bonded polypropylene. The drum was allowed to rotate
completely 6 times, thus allowing a given point on the layer of fibers to pass
through
the row of jets 6 times. The pressure of the water emanating from the jets was
variable.
The lamination strength for each sample was measured using the Lamination
Strength Test performed as follows (to yield a Lamination Strength Value
(LSV)):
A 1in. x lin. sample of the material (comprising an anchoring layer and a
fibrous layer having fibers entangle about the anchoring layer) to be measured
was cut.
The sample was mounted flat, with double face adhesive tape (Scotch double-
coated
tape Model #666), on the surfaces of two stainless steel cubes (having surface
dimensions of approximatelylin. x lin.) and the sample is thus sandwiched
between the
two cube faces. The mounted sample is compressed between the cubes for at
least 6
seconds at 5 psi or more. Next the cubes are crosshead pulled apart at a
crosshead
speed of 2 inches/minute and the force over time is measured using an Instron
force-
measurement gauge. The Lamination Strength Value is equal to the peak load
(related
to the first peak on the Instron output graphics display) recorded for the
sample.
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The following drapeability test was performed on various fibrous, non-woven
structures to determine the drapeability (basis weight/MCB) according to the
present
invention. Modified Circular Bend Stiffness (MCB) is determined by a test that
is
modeled after the ASTM D 4032-82 CIRCULAR BEND PROCEDURE, the procedure
being considerably modified and performed as follows. The CIRCULAR BEND
PROCEDURE is a simultaneous multi-directional deformation of a material in
which
one face of a specimen becomes concave and the other face becomes convex. The
CIRCULAR BEND PROCEDURE gives a force value related to flexural resistance,
simultaneously averaging stiffness in all.directions.
The apparatus necessary for the CIRCULAR BEND PROCEDURE is a modified
Circular Bend Stiffness Tester, having the following parts:
1. A smooth-polished steel plate platform, which is 102.0 mm by 102.0 mm by
6.35 mm having an 18.75 mm diameter orifice. The lap edge'of the orifice
should be at
a 45 degree angle to a depth of 4.75 mm;
2. A plunger having an overall length of 72.2 mm, a diameter of 6.25 mm, a
ball
nose having a radius of 2.97 mm and a needle-point extending 0.88 mm therefrom
having a 0.33 mm base diameter and a point having a radius of less than-0.5
mm, the
plunger being mounted concentric with the orifice and having equal clearance
on all
sides. Note that the needle-point is merely to prevent lateral movement of the
test
specimen during testing. Therefore, if the needle-point significantly
adversely affects
the test specimen (for example, punctures an inflatable structure),'than the
needle-point
should not be used. The bottom of the plunger should be set well above the top
of the
orifice plate. From this position, the downward stroke of the ball nose is to
the exact
bottom of the plate orifice;
3. A force-measurement gauge and more specifically an Instron inverted
compression load cell. The load cell has a load range of from about 0.0 to
about 2000.0
g;
4. An actuator and more specifically the Instron Model No. 1122 having an
inverted compression load cell. The Instron 1122 is made by the Instron
Engineering
Corporation, Canton, Mass.
In order to perform the procedure for this test, as explained below., three
representative samples for each article are necessary. The location of the non-
woven
structure to be tested is selected by the operator. A 37.5 mm by
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37.5 mm test specimen is cut from each of the three samples at corresponding
locations.
Prior to cutting the samples any release paper or packaging material is
removed and any
exposed adhesive, such as garment positioning adhesive, is covered with a non-
tacky
powder such as talc or the like. The talc should not affect the BW and MCB
measurements.
The test specimens should not be folded or bent by the test person, and the
handling of specimens must be kept to a minimum and to the edges to avoid
affecting
flexural-resistance properties.
The procedure for the CIRCULAR BEND PROCEDURE is as follows. The
specimens are conditioned by leaving them in a room that is 21 C, +/-1 C. and
50%, +/-
2.0%, relative humidity for a period of two hours.
The .weight of each cut test specimen is measured in grams and divided by a
factor of '
0.0014. This is the basis weight in units of grams per square meter (gsm). The
values
obtained for the basis weight for each of the samples is averaged to provide
an average
basis weight (BW). This average basis weight (BW) may then be utilized in the
formulas set forth above.
A test specimen is centered on the orifice piatform below the plunger such
that
the body facing layer of the test specimen is facing the plunger and the
barrier layer of
the specimen is facing the platform. The plunger speed is set at 50.0 cm per
minute per
full stroke length. The indicator zero is checked and adjusted, if necessary.
The
plunger is actuated. Touching the test specimen during the testing should be
avoided.
The maximum force reading to the nearest gram is recorded. The above steps are
repeated until all of three test specimens have been tested. An average is
then taken
from the three test values recorded to provide an average MCB stiffness. This
average
MCB 'value may then be used in the formulas set forth above. Drapeability is
calculated as basis weight divided by the average MCB value determined above.
The following density test was performed on various thin layers of fibers and
fibrous, non-woven structures to determine the thickness, according to the
present
invention.
Strips of material of 5 cm width are cut. To measure tensile strength in
machine
direction, strips are oriented such that machine direction is oriented
longitudinally. To
measure tensile strength in cross-machine direction, strips are oriented such
that cross-
machine direction is oriented longitudinally. The procedure was accomplished
using
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an Emveco gauge using an applied pressure of 0.07psi over a foot size of 2500
mm2.
The digital readout is accurate to 0.0025cm. An average of 5 readings was
recorded as
the thickness. The foot of the gauge is raised and the product sample is
placed on the
anvil such that the foot of the gauge is approximately centered on the
location of
interest on the product sample. When lowering the foot, care must.be taken to
prevent
the foot from dropping onto the product sample or from undue force being
applied.
The foot was lowered at a rate of 0.1 inches/second. A load of 0.07 p.s.i.g.
is applied to
the sample and the read out is allowed to stabilize for approximately 10
seconds. The
thickness reading is then taken. This procedure is repeated for at least three
product
samples and the average thickness is then calculated. Density was then
calculated by
dividing mass of the sample by the volume (length times width times average
thickness,
as determined above)
EXAMPLE 1A
The spunbond material layer as placed "under" the fibrous layer (i.e., the
fibrous layer was positioned between the jets and the fluid-permeable
anchoring layer).
The jet pressure was 1500 psi. The web was moved across the jets 4 times. The
resulting layered, composite material had a lamination strength (LSV) of
25grams (g.),
a thickness of 0.77nun, a basis weight of 85 gsm, a density of 0.11 'g/cc, and
a
drapeability of 7.9 gsmlg.
EXAMPLE 1 B
The spunbond material layer as placed under the fibrous layer. The jet
pressure
was 1500 psi. The web was moved across the jets 8 times. The resulting
layered,
composite material had a lamination strength of 65grams (g.), a thickness of
0.73mm, a
basis weight of 88 gsm, a density of 0.12 g/cc, and a drapeability of 8.6
gsm/g.
EXAMPLE 1 C
The spunbond material layer as placed on top of the fibrous layer: The jet '
pressure was 1500 psi. The web was moved across the jets 4 times. The
resulting
layered, composite material had a lamination strength of 32grams (g.), a
thickness of
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0.90mni, a basis weight of 90 gsm, a density of 0.10 g/cc, and a drapeability
of 9.1
gsm/g.
EXAMPLE 1D
The spunbond material layer as placed on top of the fibrous layer. The jet
pressure was 1500 psi. The web was moved across the jets 8 times. The
resulting
layered, composite material had a lamination strength of 106grams (g.), a
thickness of
0.85mm, a basis weight of 83 gsm, a density of 0.10 g/cc, and a drapeability
of 11.8
gsm/g.
EXAMPLE lE
The spunbond material layer as placed on bottom of the fibrous layer. The jet
pressure was 2000 psi. The web was moved across the jets 4 times. The
resulting
layered, composite material had a lamination strength of 47 grams (g.), a
thickness of
0.79mm, a basis weight of 86 gsm, a density of 0.11 g/cc, and a drapeability
of 8.5
gsm/g.
EXAMPLE 1 F
The spunbond material layer as placed on bottom of the fibrous layer. The jet
pressure was 2000 psi. The web was moved across the jets 8 times. The
resulting
layered, composite material had a lamination strength of 281 grams (g.), a
thickness of
0.78mm, a basis weight of 89 gsm, a density of 0.12 g/cc, and a drapeability
of 10.3
gsm/g-
EXAMPLE 1G
The spunbond material layer as placed on top of the fibrous layer. The jet
pressure was 2000 psi. The web was moved across the jets 4 times. The
resulting
layered, composite material had a lamination strength of 205 grams (g.), a
thickness of
0.86mm, a basis weight of 83 gsm, a density of 0.10 g/cc, and a drapeability
of 12.5
gsm/g.
^aaa~~aaaaa~a~~a~a~a~araaaa~~~aaaaiiaa~aaaaaaaaaaaaa~aaa~aa~~a~aaa~awa^
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EXAMPLE 1H
The spunbond material layer as placed on top of the fibrous layer. 'I'he jet
pressure was 2000 psi. The web was moved across the jets 8 times. The
resulting
layered, composite material had a lamination strength of 341 grams (g.), a
thickness of
0.92mm, a basis weight of 83 gsm, a density of 0.10 g/cc, and a drapeability
of 11.8
gsrii/g=
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~r~^
EXAMPLE 2
In each of the following examples, a target web was placed on a 80-mesh metal
screen forming surface, on a rotating cylindrical drum. The target web
consisted of a
layer of fibrous material between two separate fluid-permeable anchoring
layers. The
fluid permeable anchoring layer used was a 12gsm layer of spun-bonded
polypropylene, commercially available from BBA Fiberweb. The fibrous material
was
either a blend of 70% rayon fibers and 30% polyester fibers of varying basis
weight or
pulp. The drum was rotated to move the layer of fibers at a linear speed of
100 fpm.
The jets were oriented to expel a stream of pressurized water to strike the
target web
perpendicularly to the target web. The jets were arranged in a row of spaced
to a jet
density of 30 jetslinch. Aside from the pulp layers, all fibrous layers of
synthetic fiber
were subject to an initial stabilization treatment in which water was urged
though each
of a number of 0.005-inch diameter jets at 600 psi to loosely bond the fibers
prior to
entangling with the spun-bonded polypropylene (and are referred to in Table 2
as "pre-
bond"). The drum was allowed to rotate completely a varying number of times.
The
pressure of the water emanating from the jets was variable.
COMPARATIVE EXAMPLE 2A
The fibrous layer consisted of pulp. The jet pressure was 600 psi. The web was
moved across the jets 4 times. The resulting layered, composite material had a
lamination strength of 1g. at the top interface (closest to the jets) and a
lamination
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WO 2008/005107 PCT/US2007/011708
strength of lg. at the bottom interface (furthest from the jets), a thickness
of 1.65mm, a
basis weight of 204 gsm, a density of 0.124 g/cc, and a drapeability of 1.47
gsm/g.
COMPARATIVE EXAMPLE 2B
The fibrous layer consisted of mercerized pulp. The jet pressure was 600 psi.
The web was moved across the jets 7 tirnes. The resulting layered, composite
material
had a lamination strength'of 2g. at the top interface (closest to the jets)
and a lamination
strength of lg. at the bottom interface (furthest from the jets),'a thickness
of 1.69mm, a
basis weight of 197 gsm, a density of 0.117 g/cc, and a drapeability of 1.35
gsm/g.
EXAMPLE 2C
The fibrous layer consisted of mercerized pulp. The jet pressure was 1200 psi.
The web was moved across the jets 4 times. The resulting layered, composite
material
had a lainination strength of 41g. at the top interface (closest to the jets)
and a
lamination strength of 6g. at the bottom interface (furthest from the jets), a
thickness of
1.42mm, a basis weight of 195 gsm, a density of 0.137 g/cc, and a drapeability
of 1.40
gsm/g.
EXAMPLE 2D
The fibrous layer consisted of mercerized pulp. The jet pressure was 1200 psi.
The web was moved across the jets S times. The resulting layered, composite
material
had a lamination strength of 100g. at the top interface (closest to the jets)
and a
lamination strength of 31g. at the bottom interface (furthest.from the jets),
a thickness
of 1.58mm, a basis weight of 207 gsm, a density of 0.131 g/cc, and a
drapeability of
1.25 gsm/g.
EXAMPLE 2E
The fibrous layer consisted of mercerized pulp. The jet pressure was 1200 psi.
The web was moved across tbe jets ] 6 times. The resulting layered, composite
material
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had a lamination strength of 255g. at the top interface (closest to the jets)
and a
lamination strength of 109g. at the bottom interface (furthest from the jets),
a thickness
of 1.32nun, a basis weight of 192 gsm, a density of 0.145 g/cc, and a
drapeability of
1.39 gsmlg.
EXAMPLE 2F
The fibrous layer consisted of the blend of synthetic fiber. The jet pressure
was
1500 psi. The web was moved across the jets 4 times. The resulting layered,
composite material had a lamination strength of 23g. at the top interface
(closest to the
jets) and a lamination strength of 11g. at the bottom interface (furthest from
the jets); a
thickness of 0.95mm, a basis weight of 98 gsm, a density of 0.103 g/cc, and a
drapeability of 4.90 gsrn/g.
EXAMPLE 2G
The fibrous layer consisted of the blend of synthetic fiber. The jet pressure
was
1500 psi. The web was moved across the jets 8 times. The resulting layered,
composite material had a lamination strength of 35g. at the top interface
(closest to the
jets) and a lamination strength of 24g. at the bottom interface (furthest from
the jets), a
thickness of 0.89mm, a basis weight of 97 gsm, a density of 0.109 -g/cc, and a
drapeability of 5.39 gsm/g.
srrRrrrrrRR~rRRRRrRrRRrrRR\R1rRrr\rRrrrrRRrrrrRrrrrRR~~irrrRrR\R/rRRRr^
EXAMPLE 3
In each of the following examples, samples were placed on a topographical
forming surface (an acetal sleeve) having an arrangement of peaks and valleys
in a
"tricot" pattern, similar to those described in U.S. patent 5,827,597, and
also including
a pattern of raised flowers. The fluid permeable anchoring layer used was a 10
gsm
layer of spun-bonded fabric commercially available from BBA Fiberweb. The drum
was rotated to move the layer of fibers at a linear speed of 100 fpm. The jets
were in
oriented perpendicularly to the layer of fibers and arranged in a row of
spaced to a jet
density of 30 jets/inch. The drum was allowed to rotate completely 6 times,
thus
allowing a given point on the layer of fibers to pass through the row of jets
6 times.
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Example 3A
The layer of fibers 920 was a pre-bonded layer of a blend of 30% polyester
fibers and 70% rayon fibers having a total basis weight of 60 gsm. The
resulting
layered, composite material had excellent lamination strength and abrasion
resistance
and well-defined images.
Example 3B
The experiment in Example 2A was repeated except that a 90 gsm layer of
mercerized pulp (Porosanier, commercially available from Rayonier Corporation)
was
placed on top of the layer of pre-bonded synthetic fibers. Lamination -and
image
definition was excellent.
Table 1 shows materials made or tested in the above examples and the density,
lamination strength, and drapeability associated therewith. Such values
clearly
illustrate the advantageous and surprisingly unique combination of high
lamination
strength and either or both of high drapeability or low density associated
with the
materials of the present invention. It is also notable from Table 1 that by
placing the
fluid-permeable anchoring layer above the fibrous layer that lamination
strength is
improved and drapeability remains high.
It is also notable that for otherwise similar process conditions, lamination
strength is surprisingly greater between the fluid-permeable anchoring layer
and the
fibrous layer when the fluid-permeable anchoring layer is oriented on top of
the fibrous
layer. These high lamination strengths are possible without compromising
drapeability
or density.
Furthermore, Table 2 illustrates that it is surprisingly possible to form
abrasion
resistant "sandwich structure" materials that simultaneously have high
drapeability, low
density and are resistant to delamination. It is also surprisingly noted that
it is possible
for such high lamination strength materials to be made at relatively low jet
pressure,
particularly for higher basis weights.
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Table 1
Position oi Lamination
anchoring strength Thickness Basis Wt Density MCB
Ex la er psi # passes (mm) (gsm) /cc Dra eabilit
IA bottom 1500 4 25 0.77 85 0_11 11 7.9
1 B bottom 1500 8 65 0.73 88 0.12 10 8.6
1 C top ' 1500 4 32 0.90 90 0.10 10 9.1
' 1 D top 1500 8 106 0.85 83 0.10 7 11.8
1 E bottom 2000' 4 47 0.79 86 0.11 10 8.5
1 F bottom 2000 8 281 0.78 89 0.12 9 _ 10.3
IG top 2000 4 205 0.86 83 0.10 7 12.5
0 1H to 2000 8 341 0.92 90 0.10 8 11.8
Table 2
Lamination Stmg., g Thickness; Basis Wt; Density MCB
Ex Core psi # asses Top Face Bottom mm gsm /cm3 MCB, Dra eab
Compi poro pulp 600 4 1 1 1.65 204 0.124 139 1.47
0 Comp2 poro pulp 600 7 2 1 1.69 197 0.117 146 1.35
3 poro pulp 1200 4 41 6 1.42 195 0.137 139 1.40
4 poro pulp 1200 8 100 31 1.58 207 0.131 165 1.25
poro pulp 1200 16 255 109 1.32 192 0.145 138 1.39
7 poro pulp 1500 4 131 22 1.48 208 0.141 130 1.60
8 pre-bond 1500 4 23 11 =0.95 98 0.103 20 4.90
9 pre-bond 1500 8 35 24 0.89 97 0.109 18 5.39
28
