Note: Descriptions are shown in the official language in which they were submitted.
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TAMPON WITH ANGLED FIBER ORIENTATION
FIELD OF THE INVENTION
This invention relates to catamenial tampons, and more particularly to a
tampon
made from a nonwoven pad comprised of diagonally-oriented fibers which is
preferably
provided with a sewn cord, overwrapped, and compressed.
BACKGROUND OF THE INVENTION
Tampons are generally formed by providing a mass or butt of nonwoven absorbent
fibers predominately aligned longitudinally, vverwrapping the mass of fibers,
cutting the
overwrapped nonwoven mass of fibers to form a rectangular pad, providing a
withdrawal
cord which is sewn across the middle of the pad perpendicular to the fiber
alignment and
across sufficient fibers to permit withdrawal, and compressing the sewn
overwrapped
nonwoven pad parallel to the cord orientation and then perpendicular to the
cord. The
overwrapping is typically an outer covering of a liquid permeable material,
which is
designed to improve the lubricity of the tampon, to reduce insertion and
withdrawal
forces, and to prevent fibers of the mass of fibers from being detached (or
"fiber fluff
o$') during insertion and withdrawal. Examples of tampons made in this manner
are
described in U.S. Patent 3,058,468 issued to Griswold, et al. on October 16,
1962 and
U.S. Patent 3,371,666 issued to Lewing on March 5, 1968.
One problem which may occur is the peeling back of the overwrap from the
surface of the absorbent nonwoven material during compression. This may occur
since
the overwrap is open at the cut sides of the rectangular pad, the sides
parallel to the sewn
cord. The exposed absorbent may cause discomfort and disturb the user, and may
result
in absorbent fibers being detached ("fiber fluff off') during insertion and
withdrawal of
the tampon by a user.
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SUMMARY OF THE INVENTION
This invention relates to catamenial tampons, and more particularly to a
tampon
made from a nonwoven pad comprised of diagonally-oriented fibers which is
preferably
provided with a sewn cord, overwrapped, and compressed.
The tampon of the present invention is formed by providing a nonwoven mass or
batt of layers of absorbent fibers with the fibers oriented diagonally across
each layer.
The fibers can be oriented at any suitable angle. The fibers are preferably
arranged with
about 75% of the fibers oriented so that they form an angle of between about
35 and
about 55 degrees with the withdrawal cord. In especially preferred
embodiments, the
fibers are oriented at an angle of approximately 45 degrees across each layer,
alternating
the fiber orientation of successive layers. The tampon is preferably formed by
overwrapping the mass of fibers (sometimes referred to as a "pledget"),
cutting the
overwrapped nonwoven layered mass of fibers, to form a substantially flat and
generally
rectangular pad, providing a withdrawal cord sewn across the middle of the pad
perpendicular to the cut sides of the pad, compressing the sewn overwrapped
nonwoven
layered pad parallel to the cord orientation and perpendicular to the cord
orientation.
The tampon of the invention deploys with increased lateral and/or radial
expansion
and decreased longitudinal expansion resulting from the angle of the
compressed fibers
not being predominately perpendicular to the axis of the tampon; in some
cases, reducing
leakage without causing discomfort and disturbing the user.
In one embodiment, the tampon comprises an absorbent pad with overwrapping
disposed continuously around the generally rectangular pad from end to end,
but the
overwrapping is open at the cut sides of the rectangular pad, the sides
parallel to the sewn
cord. In preferred embodiments of the invention, the tampon has a continuous
overwrap
around the circumferential surface and the cut sides of the overwrapped pad
are at the
ends.
In other preferred embodiments of the invention, the overwrap is overlapped in
the middle of the pad and the withdrawal cord is sewn on the pad through both
laps ~f the
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overwrap which secures the overwrap in place without the hard spots on the
tampon
which may result from bonding of the overwrap to the absorbent material.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an exploded perspective view which shows four layers of nonwoven
absorbent material with alternating fiber orientation used to make one
preferred
embodiment the tampon of the present invention.
Fig. 2 is a schematic perspective view of the four layers assembled into a pad
with
a withdrawal cord sewn onto the pad without an overwrap.
Fig. 3 is a perspective view of one embodiment of the invention with the
assembled pad overwrapped open at the sides and with a withdrawal cord sewn
onto the
pad.
Fig. 4 is a perspective view of another embodiment of the invention with the
assembled pad overwrapped open at the ends and with a withdrawal cord sewn
onto the
pad.
Fig. 5 is a perspective view of the embodiment shown in Fig. 4 after it has
been
compressed into a tampon.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to catamenial tampons, and more particularly to a
tampon
made from a nonwoven pad comprised of diagonally-oriented fibers which is
preferably
provided with a sewn cord, overwrapped, and compressed.
A preferred tampon and the stages for making the tampon of the present
invention
is illustrated by Figs. 1, 4 and 5.
Fig. 1 shows several nonwoven layers of fibers that are used to make a
preferred
embodiment of the tampon of the present invention. There are generally four
rectangular
layers of nonwoven material shown in Fig. 1. These are designated 22, 24, 26,
and 28.
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Each of the nonwoven layers comprises a plurality of fibers, designated 23,
25, 27, and
29, respectively. The fibers preferably comprise cotton, rayon, or blends
thereof. The
layers 22, 24, 26, and 28 are preferably formed by carding the fibers,
however, other
suitable processes can be used.
It should be understood that the fibers are shown schematically in a very
regular
and orderly arrangement in Fig. 1 for purposes of illustration. In an actual
tampon, the
fibers will typically be smaller in diameter, and more random in orientation
and will often
have a degree of waviness along their length, rather than being perfectly
linear as shown.
The fibers 23, 25, 27, and 29 in the nonwoven layers are predominantly
oriented
diagonally relative to the longitudinal centerline L of the generally
rectangular layers (and
the pad into which the layers are formed). The longitudinal centerline of the
rectangular
layers will typically coincide with the location of the withdrawal cord. The
longitudinal
centerline L will also typically be parallel to the longitudinal side edges of
the rectangular
layers.
The fibers 23, 25, 27, and 29 can form any suitable angle with the
longitudinal
centerline L. It should be understood that carded fiber strands cannot be
formed with an
extremely high degree of precision. Thus, each layer will have some fibers in
all possible
orientations. The term "predominantly" as used herein, refers to the fact that
a general
orientation of the fibers can be detected. Preferably, the fibers in each
layer are
predominantly oriented at an angle of between about 35 degrees and about 55
degrees
relative to the longitudinal centerline L. Preferably, at least about 75% of
the fibers in
each layer are oriented at an angle of between about 35 degrees and about 55
degrees
relative to the longitudinal centerline L. In especially preferred
embodiments, at least
about 75% of the fibers in each layer are oriented at an angle of about 45
degrees relative
to the longitudinal centerline L.
The nonwoven layers can be formed with the fibers oriented diagonally in any
suitable manner. For example, the rectangular layers can be cut from a larger
nonwoven
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web at an angle (or on a "bias") relative to the orientation of the fibers in
the larger
nonwoven web so that the fibers in the rectangular layers will be at the
desired angle.
The tampon 20 can be comprised of any suitable number of layers of fibers. The
fibers in the different layers can all be aligned in the same general
direction and at the
same angle relative to the longitudinal centerline L. Alternatively, the
fibers in the layers
can be oriented in different directions at the same angle or at different
angles relative to
the longitudinal centerline L. In other embodiments, the fibers in the layers
can be
oriented in the same general direction, but at different angles relative to
the longitudinal
centerline L.
Fig. 1 shows an especially preferred embodiment in which the absorbent
material
in the top layer 22 has a fiber orientation of about 45 degrees relative to
the longitudinal
centerline L. The fibers 23 in layer 22 are oriented at a 45 degree angle
turned in a
counter clockwise direction from the longitudinal centerline L. The fibers 25
in the
second layer 24 have an orientation that is also 45 degees relative to the
longitudinal
centerline L of that layer, but the 45 degrees angle is turned in a clockwise
direction from
the longitudinal centerline L. Thus, the angle of the fibers 25 in the second
layer 24 are
offset 90 degees from the angle of the fibers 23 in the top layer 22. The
orientation of
the fibers 27 in the third layer 26 is the same as that of the first layer 27.
The orientation
of the fibers 29 in the fourth layer 28 is the same as that of the second
layer 24. In a
preferred embodiment, the tampon of the present invention is made by
compressing a
sewn overwrapped pad comprised of equal layers of absorbent material where the
fibers in
alternating layers are in opposite 45 degree orientations.
The layers of fibers 22, 24, 26, and 28 are preferably formed into a
substantially
flat, generally rectangular pad 30 as shown in Fig. 2. It should be
understood, however,
that the tampon of the present invention is not limited generally flat or
rectangular pads,
and the angled fiber orientation can be utilized in other tampons, including
those that are
not substantially flat or generally rectangular. The preferred pad 30 shown in
the
drawings, however, is preferably generally rectangular, and has a pair of
longitudinal side
edges 32 and a pair of end edges 34. In the preferred embodiment shown in the
drawings,
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the longitudinal side edges 32 are longer than the end edges 34. The flat pad
30
preferably has a withdrawal cord 36 joined thereto by stitching, such as with
a thread 38.
The withdrawal cord 36 preferably extends axiably along the longitudinal
centerline L of
the layers beyond one of the end edges 34 thereof. The flat pad 30 can then be
comprised
into a tampon in conventional manner, or it can be provided with an overwrap
and then
compressed. The absorbent pad material preferably has a basis weight of
between about
240 g/m2 and about 1,000 g/m2.
Numerous embodiments of the present invention are possible. For example, the
pad that is made into the tampon need not be rectangular. In other embodiments
for
example, the pad can have a chevron-shaped plan view.
In another embodiment, the tampon can be made of absorbent material which is
carded, cross-lapped, and drafted to achieve the angled fiber orientation, and
then is
preferably needle punched, slit into ribbon, ov~erwrapped, cut into
rectangular pads, sewn
with a withdrawal cord and compressed. The carded cross-lapped web will
typically have
fibers oriented at an angle of between about 15-20 degrees relative to the
cross machine
direction (a direction perpendicular to the longitudinal centerline, L). The
drafting
process straightens the angle of the fibers relative to the machine direction.
After the
cross-lapped material is drafted, the angle of the fibers is typically between
about 35-SO
degrees, and is preferably about 45 degrees. The drafting to achieve 45 degree
orientation with alternating layers of opposite orientation can be made with
the Asselin
Octoweb Drafter, manufactured by N. Schlumberger & Cie, Guebwiller Cedex,
France.
Needle punching is used to stabilize the cross-lapped nonwoven web.
The layers of fibers can be provided with an overwrap 40 which is folded
around
the ends 34 of the layers as shown in Fig. 3. The overwrap 40 can be comprised
of any
material known as being suitable for this particular purpose. The overwrap 40
is
preferably comprised of a nonwoven material having a basis weight of between
about 10
g/m2 and about 20 g/mz. In a preferred embodiment, the overwrap 40 is folded
around
the sides 32 of the layers and is secured by overlapping and by the sewing on
of the
withdrawal cord 36 and is illustrated by Fig. 4. In other embodiments, one or
more
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overwraps can be used to wrap around both the sides and the ends of the pad
30. Fig. 5
shows the preferred overwrapped pad 30 shown in Fig. 4 which has been
compressed
longitudinally and transversely to form the finished tampon 20.
The tampon can be inserted into the wearer's vaginal cavity digitally, or with
the
use of an applicator. The tampon is preferably placed in an applicator for
insertion into
the wearer's vaginal cavity. The applicator can be of the open end type, or a
closed end
type. Examples of suitable applicators are described in U.S. Patent 5,346,468
issued to
Campion, et al. on September 13, 1994, and U.S. Patent 5,558,631 issued to
Campion, et
al. on September 24, 1996, both of which are assigned to Tambrands, Inc.
The disclosures of all patents, patent applications (and any patents which
issue
thereon, as well as any corresponding published foreign patent applications),
and
publications mentioned throughout this patent application are hereby
incorporated by
reference herein. It is expressly not admitted, however, that any of the
documents
incorporated by reference herein teach or disclose the present invention. It
is also
expressly not admitted that any of the commercially available materials or
products
described herein teach or disclose the present invention.
While particular embodiments of the present invention have been illustrated
and
described, it would be obvious to those skilled in the art that various other
changes and
modifications can be made without departing from the spirit and scope of the
invention.
