Note: Descriptions are shown in the official language in which they were submitted.
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DIAPER HAVING EXTENSIBLE TRANSVER~~BARRIER
FIELD OF THE INVENTION
' The present invention relates to disposable absorbent articles, and more
particularly to disposable absorbent articles, such as diapers, having a
transverse
partition which both minimizes the migration of fecal material deposited on
the
disposable absorbent article, and which accommodates the receipt and migration
of fecal material.
BACKGROUND OF THE INVENTION
Disposable absorbent articles, such as diapers, are well known in the art.
Disposable absorbent articles retain and absorb body exudates, such as urine
and fecal material deposited thereon.
Significant advances have been made in the art relative to absorbing and
retaining urine deposits. For example, disposable absorbent articles seldom
leak and may be relatively thin due to the incorporation of absorbent gelling
materials.
However, fewer attempts have been made in the art to handle deposits of
fecal material in disposable absorbent articles. Fecal material has the
undesirable proclivities of smearing onto the wearer's skin, causing epidermal
irritation and complicating the task of cleaning the wearer when the soiled
diaper
or other disposable absorbent article is removed.
To overcome these proclivities, certain attempts have been made in the art
to isolate the fecal material from the skin of the wearer. Such attempts
generally
provide a void or hole into which the fecal material is deposited and retained
(hopefully), so that the location of the fecal material is limited to the
position of
the void or hole. Examples of such attempts are found in U.S. Patent 4,662,877
issued May 5, 1987, to Williams; U.S. Patent 4,892,536 issued January 9, 1990,
to DesMarais et al.; U.S. Patent 4,968,312 issued November 6, 1990, to Khan;
. U.S. Patent 4,990,147 issued February 5, 1991, to Freeland; U.S. Patent
5,062,840 issued November 5, 1991, to Holt et al.
Other attempts have been made in the art to provide cups which attempt to
circumscribe the anal opening, the genitalia, or both in an attempt to isolate
these regions of the wearer's body. These attempts can be uncomfortable for
the wearer and require precise positioning of the cup.
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In still another attempt, resilient barriers extending transversely or
longitudinally have been placed below the topsheet of the diaper. But this
arrangement suffers from the drawback that fecal material deposited on the
topsheet is above the barrier, can still migrate and still cause the
aforementioned problems. This arrangement simply does not provide the abrupt
discontinuity necessary to obstruct migration of fecal material deposited on
the
topsheet of the diaper.
Furthermore, such an arrangement may even be ineffective in preventing
excessive transverse migration of the fecal material. A barrier disposed below
the topsheet cannot be easily joined to longitudinally extending barrier leg
cuffs,
which, as are well known in the art, minimize leakage from the diaper. Thus,
fecal material which is channeled towards transverse migration by the barrier
may be transported to the perimeter of the diaper and breach the perimeter,
causing leakage.
It has been found that the transverse barrier is preferably rearwardly angled,
i.e., angled towards the rear waist margin of the diaper. A transverse
partition
which makes an acute angle of 45 to 85 degrees with the plane of the topsheet
has been found to be particularly effective, as disclosed in commonly assigned
U.S. Patent Application Serial No. 081664,603, filed June 18, 1996, Issue
Batch
No. J78, the disclosure of which is incorporated herein by reference.
However, Applicants have further found that merely providing a transverse
barrier with a rearward angle d~~es not necessarily provide the optimum
arrangement for accommodating fecal material deposited on the diaper. As the
fecal material migrates towards the front of the diaper, it is captured, or
retained in
position by the transverse barrier. As additional fecal material migrates
forward,
the transverse barrier preferably expands, to accommodate the presence and
volume of the fecal material. If the transverse barrier does not expand, a
damming effect may occur. The volume of the damming fecal material is
constant.
If the volume is too great, the fecal material may build up and breach the top
of the
transverse barrier. It the fecal material crosses the transverse barrier, it
typically
smears the wearer's genitals - making cleanup more difficult.
Accordingly, it is an object of the present invention to provide a disposable
absorbent article, such as a diaper, having a transverse barrier which limits
the
migration of fecal material. It is further an object of this invention to
provide a
disposable absorbent article having such a transverse barrier which
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3
accommodates the volume of fecal material deposited on the diaper and which
contacts the transverse barrier.
It is finally an object of the present invention to provide a disposable
absorbent article having a transverse barrier which defines a volume, which
volume can increase to accommodate fecal material therein.
BRIEF SUMMARY OF THE INVENTION
The present invention comprises a disposable absorbent article, such as a
diaper. The article has a longitudinal axis and a lateral axis orthogonal
thereto.
The longitudinal and lateral axes define the plane of the diaper. The diaper
has a
Z-direction orthogonal to the plane of the diaper and orthogonal to the plane
defined by the longitudinal and lateral axes of the diaper. The diaper further
has a
periphery defined by a front waist margin, a rear waist margin, and two
longitudinal
side margins connecting the front and rear waist margins.
The diaper further comprises a liquid pervious topsheet, a liquid impervious
backsheet joined to the topsheet, an absorbent core intermediate the topsheet
and the backsheet, and a pair of upstanding barrier leg cuffs. Each barrier
leg cuff
extends outwardly from a proximal end joined to the topsheet to a distal end
spaced from the proximal end. The barrier leg cuffs are generally
longitudinally
oriented.
The diaper further comprises a laterally oriented transverse barrier. The
transverse barrier is joined to the topsheet at a proximal end and extends
outwardly therefrom. The transverse barrier is further joined to each of the
barrier
leg cuffs.
The diaper has a fecal material containing volume. The fecal material
containing volume is defined by and contained within the proximal and distal
ends
of the transverse barrier and the barrier leg cuffs. The fecal material
containing
volume is increasable upon the deposition of fecal material therein and which
intercepts the transverse barrier.
The transverse barrier may be extensible, whereby the fecal material
containing volume is increasable upon the receipt of fecal material therein.
Furthermore, the transverse barrier may be elastically extensible. The
transverse
barrier may comprise an elastic panel. The panel may be elastically extensible
in
the longitudinal direction, the lateral direction, or bilaterally extensible.
Alternatively, the elasticity may be provided by a series of elastic strands.
In yet
another embodiment, the extensibility need not be elastic, but may, for
example,
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be provided by pleats having releasable frangible bonds. The bonds are broken
upon receipt of or pressure due to the presence of fecal material. Any such
embodiment is sufficient, so long as the fecal material containing volume is
increasable upon receipt of fecal material therein, and preferably which does
increase in response to the presence of fecal material contacting the
transverse
barrier.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a top plan view of the disposable absorbent article according to
the present invention shown partially in cutaway and having no elastic induced
contraction.
Figure 2 is an offset vertical sectional view taken along line 2-2 of Fig. 1.
Figure 3 is a fragmentary instant vertical sectional view taken along line 3-3
of Fig. 1.
Figure 4 is a fragmentary instant vertical sectional view, similar to that of
Fig.
3 illustrating the effect of the presence of fecal material within the fecal
material
containing volume.
Figure 5 is a schematic perspective view of the portion of the diaper shown in
Fig. 3, illustrating the fecal material containing volume.
Figure 6 is a frontal elevational view of a transverse partition having an
extensible central tri-section and inextensible outboard trisections.
Figure 7 is a frontal elevationai view of a transverse partition having an
extensible central tri-section which tapers to a lesser width as the proximal
edge of
the transverse partition is approached.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term "absorbent article" refers to devices which absorb
and contain body exudates, and, more specifically, refers to devices which are
placed against or in proximity to the body of the wearer to absorb and contain
the various exudates discharged from the body. The term "disposable" is used
herein to describe absorbent articles which are not intended to be laundered
or
otherwise restored or reused as an absorbent article (i.e., they are intended
to
be discarded after a single use and, preferably, to be recycled, composted or
otherwise disposed of in an environmentally compatible manner). A "unitary"
absorbent article refers to absorbent articles which are formed of separate
parts
united together to form a coordinated entity so that they do not require
separate
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manipulative parts Pike a separate holder and liner. A preferred embodiment of
an absorbent article of the present invention is the unitary disposable
absorbent
article, diaper 20, shown in Figure 1. As used herein, the term "diaper"
refers to
an absorbent article generally worn by infants or incontinent persons about
the
' lower torso of the wearer. It should be understood, however, that the
present
invention is also applicable to other absorbent articles such as incontinent
briefs,
incontinent undergarments, diaper holders and liners, certain feminine hygiene
garments, and the like.
Figure 1 is a plan view of the diaper 20 of the present invention in its flat-
out, uncontracted state (i.e., with elastic induced contraction pulled out)
with
portions of the structure being cut-away to more clearly show the construction
of
the diaper 20 and with the portion of the diaper 20 which faces or contacts
the
wearer, the inner surface, oriented towards the viewer. As shown in Figure 1,
the diaper 20 preferably comprises a liquid pervious topsheet 24; a liquid
impervious backsheet 26 joined with the topsheet 24; an absorbent core 28
positioned between the topsheet 24 and the backsheet 26; elasticized barrier
leg
cuffs 32; a fastening system 36 generally multiply designated as 36; and an
upstanding transverse partition 38.
The topsheet 24 of the diaper 20 has an outwardly oriented body facing
surface which faces (and usually contacts) the wearer while the diaper 20 is
in
use and a core facing surface opposed to the body facing surface. The body
facing surface of the topsheet 24 of the diaper 20 comprises that portion of
the
diaper 20 which is positioned adjacent the wearer's body during use (i.e., the
inner surface generally is formed by both at least a portion of the topsheet
24
and other components joined to the topsheet 24). The diaper 20 further has a
first waist region 31 oriented towards the front of the wearer while the
diaper 20
is in use, a second waist region 33 longitudinally opposite the first waist
region
31, a crotch reg ion 35
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positioned between the first waist region 31 and the second waist region 33,
and
a periphery which is defined by the outer edges of the diaper 20.
The diaper 20 has a longitudinal centerline L-L which divides the diaper 20
into left and right halves, and which divides the standing wearer into left
and
right body halves. The diaper 20 further comprises a transverse centerline T-T
orthogonal to the longitudinal centerline L-L which divides the diaper 20 into
a
front portion and a rear portion. The transverse centerline T-T is midway
between the front and rear longitudinal extremities of the diaper chassis.
Orthogonal to the mutually perpendicular longitudinal centerline L-L and
transverse centerline T-T, is a Z-direction axis, which extends outwardly from
the
plane of the diaper 20.
A component of the diaper 20 is considered to be transversely oriented,
and hence "transverse" if such component forms an angle of ~ 45 degrees or
less with the transverse centerline T-T. Similarly, a component is considered
to
be longitudinally oriented, and hence "longitudinal" if such component forms
an
angle of + 45 degrees or less with the longitudinal centerline L-L.
Figure 1 shows a preferred embodiment: of the diaper 20 in which the
topsheet 24 and the backsheet 26 have length and width dimensions generally
larger than those of the absorbent core 28. The topsheet 24 and the backsheet
26 extend beyond the edges of the absorbent core 28 to thereby form the
periphery of the diaper 20. While the topsheet 24, the backsheet 26, and the
absorbent core 28 may be assembled in a variety of well known configurations,
preferred diaper configurations are described generally in U.S. Patent
3,860,003
entitled "Contractable Side Portions for Disposable Diaper" which issued to
Kenneth B. Buell on January 14, 1975, which is incorporated herein by
reference.
The absorbent core 28 may be any absorbent means which is generally
compressible, conformable, non-irritating to the wearer's skin, and capable of
absorbing and retaining liquids such as urine and other certain body exudates.
As shown in Figure 1, the absorbent core 28 has a garment surface, a body
surface, side edges, and waist edges. The absorbent core 28 may be
manufactured in a wide variety of sizes and shapes (e.g., rectangular,
hourglass, "T'-shaped, asymmetric, etc.) and from a wide variety of liquid-
absorbent materials commonly used in disposable diapers and other absorbent
articles such as comminuted wood pulp which is generally referred to as
airfelt.
Examples of other suitable absorbent materials include creped cellulose
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wadding; meltblown polymers including coform; chemically stiffened, modified
or
cross-linked cellulosic fibers; tissue including tissue wraps and tissue
laminates;
absorbent foams; absorbent sponges; superabsorbent polymers; absorbent
gelling materials; or any equivalent material or combinations of materials.
The
configuration and construction of the absorbent core 28 may also be varied
(e.g., the absorbent core 28 may have varying caliper zones, a hydrophilic
gradient, a superabsorbent gradient, or lower average density and lower
average basis weight acquisition zones; or may comprise one or more layers or
structures). The total absorbent capacity of the absorbent core 28 should,
however, be compatible with the design loading and the intended use of the
diaper 20. Further, the size and absorbent capacity of the absorbent core 28
may be varied to accommodate wearers ranging from infants through adults.
Exemplary absorbent structures for use as the absorbent core 28 are described
in U.S. Patent 4,610,678 entitled "High-Density Absorbent Structures" issued
to
Weisman et al. on September 9, 1986; U.S. Patent 4,673,402 entitled
"Absorbent Articles With Dual-Layered Cores" issued to Weisman et al. on June
16, 1987; U.S. Patent 4,888,231 entitled "Absorbent Core Having A Dusting
Layer" issued to Angstadt on December 19, 1989; and U.S. Patent 4,834,735,
entitled "High Density Absorbent Members Having Lower Density and Lower
Basis Weight Acquisition Zones", issued to Alemany et al. on May 30, 1989.
Each of these patents are incorporated herein by reference.
The backsheet 26 is positioned adjacent the garment surface of the
absorbent core 28 and is preferably joined thereto by attachment means (not
shown) such as those well known in the art. For example, the backsheet 26
may be secured to the absorbent core 28 by a uniform continuous layer of
adhesive, a patterned layer of adhesive, or an array of separate lines,
spirals, or
spots of adhesive. Adhesives which have been found to be satisfactory are
manufactured by H. B. Fuller Company of St. Paul, Minnesota and are marketed
as HL-1258. The attachment means will preferably comprise an open pattern
network of filaments of adhesive as is disclosed in U.S. Patent 4,573,986
entitled "Disposable Waste-Containment Garment", which issued to Minetola et
al. on March 4, 1986, more preferably several lines of adhesive filaments
swirled
into a spiral pattern such as is illustrated by the apparatus and methods
shown
in U.S. Patent 3,911;173 issued to Sprague, Jr. on October 7, 1975; U.S.
Patent
4,785,996 issued to Ziecker, et al. on November 22, 1978; and U.S. Patent
4,842,666 issued to Werenicz on June 27, 1989. Each of these patents are
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incorporated herein by reference. Alternatively, the attachment means may
comprise heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical
bonds, or any other suitable attachment means or combinations of these
attachment means as are known in the art.
The backsheet 26 is impervious to liquids (e.g., urine) and is preferably
manufactured from a thin plastic film, although other flexible liquid
impervious
materials may also be used. As used herein, the term "flexible" refers to
materials which are compliant and will readily conform to the general shape
and
contours of the human body. The backsheet 26 prevents the exudates
absorbed and contained in the absorbent core 28 from wetting articles which
contact the diaper 20 such as bedsheets and undergarments. The backsheet
26 may thus comprise a woven or nonwoven material, polymeric films such as
thermoplastic films of polyethylene or polypropylene, or composite materials
such as a film-coated nonwoven material. Preferably, the backsheet 26 is a
thermoplastic film having a thickness of from about 0.012 mm (0.5 mil) to
about
0.051 mm (2.0 mils}. Particularly preferred materials for the backsheet 26
include RR8220 blown films and RR5475 cast films as manufactured by
Tredegar Industries, Inc. of Terre Haute, IN. The backsheet 26 is preferably
embossed andlor matte finished to provide a more clothlike appearance.
Further, the backsheet 26 may permit vapors to escape from the absorbent core
28 (i.e., breathable) while still preventing exudates from passing through the
backsheet 26. The topsheet 24 is positioned adjacent the body surface of the
absorbent core 28 and is preferably at least partially peripherally joined
thereto
and to the backsheet 26 by attachment means (not shown) such as those well
known in the art. Suitable attachment means are described with respect to
joining the backsheet 26 to the absorbent core 28. As used herein, the term
"joined" encompasses configurations whereby an element is directly secured to
the other element by affixing the element directly to the other element, and
configurations whereby the element is indirectly secured to the other element
by
affixing the element to intermediate members) which in turn are affixed to the
other element. In a preferred embodiment of the present invention, the
topsheet
24 and the backsheet 26 are joined directly to each other in the diaper
periphery
and are indirectly joined together as a result of their joinder to the
absorbent
core 28 by suitable attachment means (not shown).
The topsheet 24 is compliant, soft feeling, and non-irritating to the wearer's
skin. Further, the topsheet 24 is liquid pervious permitting liquids (e.g.,
urine) to
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readily penetrate through its thickness. A suitable topsheet may be
manufactured from a wide range of materials, such as porous foams; reticulated
foams; apertured plastic films; or woven or nonwoven webs of natural fibers
(e.g., wood or cotton fibers), synthetic fibers (e.g., polyester,
polyethylene, or
' polypropylene fibers), or a combination of natural and synthetic fibers.
Preferably, the topsheet 24 is made of a hydrophobic material to isolate the
wearer's skin from liquids contained in the absorbent core 28. There are a
number of manufacturing techniques which may be used to manufacture the
topsheet 24. For example, the topsheet 24 may be a nonwoven web of fibers
spunbonded, carded, wet-laid, meltblown, hydroentangled, combinations of the
above, or the like. A preferred topsheet is carded and thermally bonded by
means well known to those skilled in the fabrics art. A preferred topsheet
comprises a web of staple length polypropylene fibers such as is manufactured
by Veratec, Inc., a Division of International Paper Company, of Waipole,
Massachusetts under the designation P-8.
The diaper 20 preferably further comprises elasticized barrier leg cuffs 32
for providing improved containment of liquids and other body exudates. Each
elasticized barrier leg cuff 32 may comprise several different embodiments for
reducing the leakage of body exudates from the leg regions of the diaper 20.
U.S. Patent 4,909,803 entitled "Disposable Absorbent Article Having
Elasticized
Flaps" issued to Aziz et al. on March 20, 1990, describes a disposable diaper
20
having "stand-up" elasticized flaps (barrier leg cuffs 32) to improve the
containment of the leg regions of the diaper 20. U.S. Patent 4,695,278
entitled
"Absorbent Article Having Dual Cuffs" issued to Lawson on September 22, 1987,
describes a disposable diaper 20 having dual cuffs including both a gasketing
cuff and a barrier cuff 32. Both of these patents are incorporated herein by
reference for the purpose of showing suitable exemplary constructions for the
barrier leg cuffs 32.
Spanning the transverse distance between the barrier leg cuffs 32 is an
upstanding transverse partition 38. The transverse partition 38 is disposed on
the body facing surface of the topsheet 24 and extending outwardly therefrom
to
present an abrupt discontinuity in the body facing surface of the topsheet 24.
As
illustrated, preferably the transverse partition 38 is generally straight,
rectilinear,
transverse and preferably parallel to the transverse centerline T-T of the
diaper
20. If desired, the transverse pattern 38 may even be coincident with the
transverse centerline T-T of the diaper 20.
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The transverse partition 38 obstructs the longitudinal migration of fecal
material deposited in the rear portion of the diaper 20 towards the front
portion
of the diaper 20. Preferably the upstanding partition 38 connects the barrier
leg
cuffs 32, forming an H-shape. This arrangement is highly preferred because it
prevents seepage of fecal material around the edges of the transverse
partition
38 and contains the fecal material in the rear portion of the diaper 20.
Referring to Figure 2, the transverse partition 38 has a proximal edge
which is preferably joined to the topsheet 24, and particularly the body
facing
surface thereof, by adhesive, by autogeneous bonding, such as is disclosed in
commonly assigned U.S. Patent 4,854,984 issued to Ball et al, which patent is
incorporated herein by reference, or by other joining means, as are well known
in the art. The transverse partition 38 extends outwardly from the plane of
the
topsheet 24 with a vector component in the Z-direction to a distal edge.
It is important the transverse partition 38 be upstanding and rise above the
plane of the topsheet 24 to an effective height H sufficient to present an
abrupt
discontinuity to obstruct the longitudinal movement of fecal material while
the
diaper 20 is worn. It is to be recognized that if the topsheet 24 has
wrinkles,
rugosities, undulations, or other deviations from planarity, these should be
taken
into account at the position of the transverse partition 38 when determining
its
effective height H. Otherwise such deviations from planarity in the topsheet
24
may diminish the effective height H of the distal edge of the partition 38
above
the topsheet 24, and not sufficiently obstruct the flow of fecal material.
As illustrated in Figure 3, the transverse partition 38 is preferably not
orthogonal to the plane of the topsheet 24, but instead is disposed in angular
relationship therewith so that the distal edge of the upstanding transverse
partition 38 is oriented towards the rear portion and the rear waist margin 33
of
the diaper 20. This arrangement provides the advantage that the pressure of
the fecal material helps seal the transverse partition 38 against the wearer's
body, minimizing the leakage of fecal material across the transverse partition
38.
This arrangement further minimizes the vertical forces necessary to maintain
the
transverse partition 38 in contact with the body of the wearer.
The transverse partition 38 has two opposed faces, a front facing surface
and a rearward facing surface. The rearward facing surface forms an acute
angle Z with the body facing surface of the topsheet 24. The acute angle Z is
preferably from 45 to 85 degrees, and more preferably from 55 to 80 degrees,
and most preferably from 65 to 75 degrees. The acute angle Z is measured in
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accordance with commonly assigned U.S. Patent Application Serial No.
08/664,603 filed June 18, 1996, Issue Batch No. J78, the disclosure of which
is
incorporated herein by reference.
The transverse partition 38 may be made of a water pervious material, but
is preferably made of a liquid impermeable material. The liquid impermeable
material prevents (or minimizes the amount of) runny fecal material reaching
the
genitalia of the wearer. Nonwoven materials, such as those commonly used to
form the barrier leg cuffs 32, have been found to be particularly suitable in
the
transverse partition 38. Other suitable materials for the transverse partition
38
include foams, formed films, etc. A suitable liquid impermeable material,
particularly a liquid impermeable nonwoven material for the transverse
partition
38 may be obtained from the Veratec Corporation of Walpole, Massachusetts as
a hydrophobic P-8 material having a basis weight of at least 20 grams per
square meter. If desired, a high basis weight spunlmeltblownlspun layered web
made of polypropylene or polyethylene as is available from Fiberweb
Corporation under the name Eclipse could be used. Alternatively, Veratec
Everspun nonwoven material may be used.
A particularly preferred transverse partition 38 for female wearers allows
fluids, such as urine, to permeate the barrier from the front to the rear, so
that
such fluid cannot sit on top of the transverse partition 38 more than
necessary
and irritate the skin. However, such a transverse partition 38 is preferably
impervious in the direction from the rear to the front of the diaper 20, for
the
same reason. Such a material may be provided as a formed film made
according to commonly assigned U.S. Patent 3,929,135 issued Dec. 30, 1975 to
Thompson, the disclosure of which is incorporated herein by reference. For
additional comfort to the wearer, a nonwoven material may be laminated to the
front of the formed film.
If desired, spacers (not shown) may be added to the distal edge of the
transverse partition 38 to locally increase its effective height H. The
spacers
may be made and disposed on the transverse partition 38 according to
commonly assigned U.S. Patent 5,554,142 issued September 10, 1996 to Dreier
et al., the disclosure of which is incorporated herein by reference.
Referring to Figure 3, the transverse barrier may be generally taut and
define a flat plane as shown. In response to the presence and contact of fecal
material with the transverse barrier, the transverse barrier may expand,
preferably to a convex configuration as shown in Figure 4. This expansion may
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be thought of as an increase in the longitudinal dimension of the transverse
barrier. The longitudinal dimension of the transverse barrier is measured from
the proximal edge of the transverse barrier to the distal edge of the
transverse
barrier, coincident the longitudinal centerline L-L of the diaper 20. Of
course, it
is to be recognized that depending upon the volume, viscosity, and disposition
of
the fecal material on the topsheet 24 of the disposable absorbent article 20,
the
configuration of the transverse barrier as it expands to accommodate the fecal
material will likely vary from that shown in Figure 4. For example, the
transverse
barrier may bow to a concave configuration, or otherwise generally increase in
the transverse dimension.
However, the important consideration is not the exact configuration of the
transverse barrier in response to pressure of fecal material thereagainst.
Instead, it is only important that the presence and volume of the fecal
material
be accommodated so that the fecal material can move forward in the
longitudinal direction without building up in the Z-direction against the
transverse
barrier and crossing the top of the transverse barrier. By allowing the
transverse
barrier to expand in the forward longitudinal direction, or in the transverse
direction while maintaining the seal between the proximal end of the
transverse
barrier and the topsheet 24, the volume of the fecal material can be accounted
for without allowing it to breach the top of the transverse barrier.
Referring to Figure 5, the disposable article according to the present
invention may be thought of as having a fecal material containing volume 50.
There is both an initial fecal material containing volume 50, i.e., that
presented by
the diaper 20 prior to being disposed on a wearer and soiled, and a secondary
fecal material containing volume 50, i.e., that which occurs after the
introduction of
fecal material against the transverse barrier. The fecal material containing
volume
50 is defined as follows. In cross section the fecal material containing
volume 50
is generally triangular and may be a right triangle. The cross section of the
fecal
material containing volume 50 is defined by the proximal and distal ends of
the
transverse barrier, and an imaginary line from the distal end of the
transverse
barrier perpendicular to the outwardly facing surface of the topsheet 24. If
the
transverse barrier is not uniform in the transverse direction, the cross
section of
the fecal material containing volume 50 is measured at the longitudinal
centerline
L-L of the disposable article.
Thus, the cross section of the fecal material containing volume 50 may be
thought of as a right triangle. One leg 51 represents the imaginary tine from
the
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distal end of the transverse barrier to the outwardly oriented surface of the
topsheet 24. The other leg 52 is taken from the rearwardly facing surface of
the
proximal end of the transverse barrier along the outwardly oriented surface of
the
topsheet 24 to the point where the imaginary line, discussed above, intersects
the
topsheet 24. The hypotenuse of the right triangle is the rearwardly facing
surface
of the transverse barrier. The fecal material containing volume 50 is further
defined by the inwardly facing surfaces, i.e., those surfaces oriented towards
the
longitudinal centerline L-L, of each of the barrier leg cuffs 32.
Thus, an infinite number of the aforementioned cross sections extending
between the two barrier leg cuffs 32 and bounded by the transverse barrier in
the
topsheet 24 is defined. The fecal material containing volume 50 is the product
of
the transverse distance between the inwardly oriented surfaces of the barrier
leg
cuffs 32, and the cross sectional area discussed above. The transverse
distance
between the barrier leg cuffs 32 is measured coincident the outwardly facing
surface of the topsheet 24.
It is this fecal material containing volume 50 which is both initially defined
and, which has a secondary volume greater than the initial volume in order to
accommodate fecal material. Thus, it is necessary to measure two fecal
material
containing volumes 50. The first fecal material containing volume 50 is
measured
with the diaper 20 in the flat, uncontracted state of Figure 1 and prior to
being
disposed on the wearer. The secondary fecal material containing volume 50 is
likewise measured in the flat, uncontracted state, but after the fecal
material is
deposited within the volume and contacts the transverse barrier.
The transverse partition 38 may comprise an elastic panel. Alternatively,
the transverse barrier may comprise an elastic panel and flaccid material. If
flaccid material is utilized, preferably it is juxtaposed with the proximal
end of the
transverse barrier. The flaccid material allows for expansion of the
transverse
partition 38 upon even minor pressure caused by contact with the fecal
material. If
an elastic panel is selected for all or a portion of the transverse barrier,
the elastic
panel is preferably elastically extensible in the longitudinal direction,
i.e., is
extensible towards the front waist margin. Alternatively, in a less preferred
embodiment, the elastic panel comprising the transverse barrier may be
elastically
extensible in the lateral direction. In still another embodiment, the elastic
panel
may be bilateraily extensible. The benefit of a bilaterally extensible elastic
panel is
its ability to provide an increase in volume 50 which volume increase is
generally
more independent of the wearer position and geometry of the diaper 20.
CA 02293626 1999-12-07
WO 98/56327 PCT/US98/11691
14
A particularly preferred material is a web material exhibiting an elastic-like
behavior and having molecular-level deformation in a first region and
geometric
deformation in a second region. Such a material may be made according to
commonly assigned U.S. Patent 5,518,801 issued May 21, 1996 to Chappell et
al., the disclosure of which is incorporated herein by reference.
in an alternative embodiment, as is well known in the art, extensibility may
be imparted to the transverse barrier through the use of multiple elastic
strands.
Preferably the elastic strands are generally parallel. Suitable material for
the
elastic strands are well known in the art. The elastic strands may be attached
to
the transverse barrier by adhesive, heat shrinking, or any of the other means
well
known in the art. Multiple elastic strands provide the benefit over an elastic
panel
of providing for variable levels of extensibility, i.e., different spring
rates, at
different locations on the transverse partition 38. Preferably the increase in
fecal
material containing volume 50 upon receipt of fecal material is from about 5
to
about 50 percent of its original volume. Upon receiving the fecal material,
the
fecal material containing volume 50 preferably has a volume of at least 30,
more
preferably at least 50, and most preferably at least 80 cubic centimeters.
Referring to Figure 6, the transverse partition 38 may comprise three tri-
sections: two outer tri-sections 60 and a central tri-section 62. The central
tri-
section 62 may be extensible, and more preferably may be elastically
extensible.
This arrangement provides the advantage that leakage over the top of the
transverse partition 38 is generally minimized, due to the stiffness imparted
by the
inextensibfe outboard tri-section 60. The tri-sections need not be equal in
width.
Referring to Figure 7, in yet another preferred embodiment, the elastic
central tri-section 62 may taper from a greater width at the distal edge of
the
transverse partition 38 to a vertex at the proximal edge of the transverse
partition
38. Of course, it is to be recognized that the vertex of the central tri-
section 62
need not be coincident the proximal edge of the central tri-section 62, but
may be
disposed between the proximal and distal edges of the transverse partition 38.
It
is to be further recognized that the extensible central tri-section 62 of the
embodiment of Figure 6 need not converge to a vertex, but may merely taper
from
a greater width at the distal edge of the transverse partition 38 to a lesser
width at
the proximal edge of the transverse partition 38. The embodiment of Figure 6
provides the advantage that there is less distortion at the distal edge of the
transverse partition 38 caused by movement of the barrier leg cuffs 32 of the
diaper 20. Furthermore, this arrangement tends to decouple movements from the
CA 02293626 1999-12-07
WO 98156327 PCT/US98/11691
core 28 from the movements of the barrier leg cuffs 32 of the diaper 20. By
decoupling movements between the core 28lieg cuffs 32 and the distal edge of
w the transverse partition 38, leakage when fecal material is present is
reduced.
It will be apparent that many variations are feasible and within the scope of
the claimed invention. The elasticity may be imparted to the transverse
barrier at
a diagonal relative to the longitudinal and lateral directions. Elastic
strands and
elastic panels may be used in combination. All such variations are within the
scope of the claimed invention.
