Note: Descriptions are shown in the official language in which they were submitted.
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DISPOSABLE UNDERPANTS
Field of the Invention
This present invention relates to underpants in general, and more specifically
to disposable
incontinence underpants having a liquid impervious region and an absorbent
layer to be used for
incontinence protection.
Backa~ound of the Invention
Regular underpants in current use are made of cotton and/or synthetic
materials. The
cotton and synthetic panties typically do not offer barrier or absorbent
protection. Often the
synthetic panties have a cotton lined crotch to absorb perspiration or vaginal
discharges. The
absorbent/barrier properties of regular undergarments are minimal such that
heavy perspiration,
incontinence or any vaginal discharge may strike through onto outer clothing
(i.e., penetration of
liquid from the interior to the exterior of the underpant.)
Cloth underpants used with other incontinence or absorbent articles, although
widely-used,
have disadvantages. Underpants with absorbent articles inserted can be
uncomfortable to some
users. Some users experience difficulty in maintaining the positioning of the
absorbent article
within the underpants, causing physical and psychological discomfort for the
users and creating
risks of leakage. In addition, if leakage should occur, the user must handle,
and when in public,
carry the wet underpants home.
Disposable training pants or disposable underpants used during the toilet
training of small
children, have been available for sometime. However, due to the differences
between small
children and adult bodies as well as the different activities and movements of
small children and
adults, simply increasing the size of disposable training pants to adult sizes
may not meet many of
the needs of adult users.
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Many of the disposable underpants currently available or disclosed include
gartneMs having
elastic members sandwiched between a liquid permeable topsheet and a liquid
impermeable
backsheet and extending substantially over the width of an absorbent core or
slightly beyond the
absorbent core, such that the elastic members, particularly those associated
with said respective
leg-holes which are important to prevent leakage around the crotch. However,
such a structure
can cause a rigidity of the absorbent core, bunching of the absorbent core, or
gaps in the elastic
structures that can result in leakage as wail as an uncomfortable fit. Other
disposable underpants
include a weld in the crotch region joining the front and near panels which
can also cause a rigidity
that results in leakage as well as an uncomfortable fd, especially where the
weld comes into
contact with the user's skin.
Other disposable underpants disclose various side seal designs, varying from
interior and
exterior side seals. The garments inGuding interior side seals, while having
an improved
appearance, can result in skin irritation. Such garments currently require
complex and expensive
manufacturing steps. The garments including exterior side seals provide a more
comfortable fit in
the side regions but do not meet the need for a garment having comfortably
fitting leg and crotch
elastic members and improved leakage that are easily manufactured.
Disposable diaper like garments, as is wail known, now find widespread use for
adult
incontinence care, as well as for infant care. The typical disposable diaper
like garment is a
three-layer composite structure comprising a liquid permeable bodyside inner
liner, a liquid
impermeable outer cover and an absorbent batt sandwiched between the liner and
the cover.
Materials now in general use for the three principal elements of the
disposable diaper like garment
include various types of norrvvoven fabrics for the bodyside liner, a thin
thermoplastic film for the
outer cover and ceilulosic fluff for the absorbent butt.
Disposable diaper like garments of the type presently on the marital are fiat
open-sided
gartneMs that ace intended to be fit about a user's body. The rear panel of
the diaper like garment
is placed over the user's buttocks while the front panel of the garment covers
the user's abdomen.
The sides of the garment are overiapped and held together by various fastening
means such as
pressure-sensitive adhesive tape.
The popularity of such disposable diaper like garments has led to a demand for
a
disposable underpant for children and the belief that there is a demand for a
disposable underpant
that can be used for adult incontinence. While disposable diaper-like garments
are available for
incontinent persons, there are many reasons as to why such garments do not
meet the needs or
desires of users. The application of the diaper like garments is typically
much more difficult,
requiring more coordination and more steps than simply pulling up a pair of
underpants. The
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appearance of the diaper like garments has a psychological effect on users,
including feelings of
loss and embarrassment.
incontinence and feminine care sanitary napkins or pads used with regular
underpants
typically have polyethylene backings that provide some barrier properties
needed to prevent liquid
strike through. However, if the strike through extends to the sides or the
ends of the pads it can
leak onto the underpants. This leakage can wet the underpant. Depending upon
the amount of
leakage, liquid may strike through or go around the undergarment to the outer
clothing and/or
bedding. Individuals having heavy incontinence problems often use one or more
pads at a time
and change the pads frequently to prevent embarrassing, messy leakage. In some
cases,
individuals experiencing heavy incontinence will restrict their activities and
stay home.
Placement of incontinence and feminine pads in the crotch of regular underpant
shows that,
at best, the pads lay on the leg elastic and, at worst, overhang the leg
elastics. This causes side
leakage onto the underpant and possibly onto outer clothing. Typical leakage
from the pads is
caused by poor 1'it of the absorbent pad to the body, improper positioning of
the pad by the user
and lack of absorbency. Leakage from the underpant onto the outer clothing is
due to
incompatibility between the absorbent pad width and the underpant crotch width
and lack of barrier
properties in the underpant material around the edge portion of the absorbent
pad. In addition,
leakage frequently results from the shifting of the absorbent pad during use
because of ineffective
placement or securement to regular underpants.
Summary Of The Invention
Briefly, this invention describes a three dimensional, disposable, discrete
underpant with
elasticized leg openings and waist portion that is circumferentially
stretchable about the hip and
stomach regions and which provides incontinence protection.
The protection benefd is obtained by providing a flexible absorbent core
associated with the
crotch area of the underpant wherein the absorbent core is maintained in
proper location for
incontinence discharge by an elastic system surrounding each teg opening. The
absorbent core
extends from the crotch area of the underpant into the body of the underpant
in front and back
body portions. This provides an underpant which is capable of trapping and
absorbing the
incontinence discharge and preventing liquid strike through onto outer
clothing and bed linen.
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Brief Descriction Of The Drawinos
The present invention will be more fully understood and further advantages
will become
apparent when reference is made to the following detailed description of the
invention and the
drawings, in which:
Figure 1a is a top plan view of a underpant article of the present invention
in a preassembled flat
configuration;
Figure 1b is a top plan view of a underpant article of the present invention
in a preassembled flat
configuration;
Figure 1c is a top plan view of a underpant article of the present invention
in a preassembled flat
configuration;
Figure 2a is a top plan view of a underpant artiGe of the present invention in
a preassembted flat
configuration;
Figure 2b is a top plan view of a underpant article of the present invention
in a preassembled flat
configuration;
Figure 3 is a top plan view of a underpant article of the present invention fn
a preassembled flat
configuration;
Figure 4 is a perspective view of a full-sized, disposable underpant of the
present invention.
Figure 6 is a perspective view of a full-sized, disposable underpant of the
present invention.
Figure 6 is a sectioned view taken along view tines 8-6 of Figure 1a and
illustrating the outer
cover, liner and elastics.
Figure T is a sectioned view taken along view lines 8-6 of Figure 2b and
illustrating the outer
cover, Itner and elastics.
Figure 8 is an exploded sectioned view taken along view lines 4-4 of Figure 1a
and illustrating the
absorbent layer, bartier and outer cover.
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Figure 9 is an exploded sectioned view taken along view lines 4-4 of Figure 2a
and illustrating the
absorbent layer, barrier and outer cover.
Detailed Descriation of the Preferred Embodiments
The following detailed description is made in the context of an article 10
inGuding a
disposable underpant 12 including an absorbent core in place during use. It is
readily apparent,
however, that the present invention can be employed for incontinence, vaginal,
perspiration
discharges, and the like in adult, child and infant products.
The disposable underpant 12 of Figure 1a illustrates the preferred embodiment
of the
present invention in a flat configuration prior to assembly. In Figure 1a, the
underpant 12 is shown
having an outer cover 13 which includes a front body portion 14, a back body
portion 15, a front
waist edge portion 44, a back waist edge portion 45, a crotch portion 18,
waist liner 26 (optional,
shown in Figures 5 and T), leg liner 38 (optional, shown Figures 5 and T) and
body liner 80. The
outer cover 13 may include a front body portion 14, a back body portion 15, a
front waist edge
portion 44, a back waist edge portion 45, and a crotch portion 18 wherein the
crotch portion 18 is
interposed between the front and back body portions 14 and 15.
The outer cover 13 is compliant and soft feeling to the wearer. The outer
cover 13 may be
any soft, flexible, porous sheet which is liquid pervious, permitting liquids
to readily penetrate into
its thickness, or impervious, resistant to the penetration of liquids into its
thickness. A suitable
outer cover 13 may be manufactured from a wide range of materials, such as
natural fibers (e.g.,
wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene
fibers) or from a
combination of natural and synthetic fibers or reticulated foams and apertured
plastic films.
There are a number of manufacturing techniques which may be used to
manufacture the
outer cover 13. For example, the outer cover 13 may be woven or nonwoven web
or sheet such
as a spunbond, meftblown or bonded-carded web composed of synthetic polymer
filaments, such
as polypropylene, polyethylene, polyesters or the like, or a web of natural
polymer filaments such
as rayon or cotton. The bonded-carded web may be thermally bonded or sprayed
with a binder by
means well known to those skilled in the fabric art. Suitably, the outer cover
13 is a nonwoven
spunbond. Ideally, the outer cover 13 is a spunbond polypropylene nonwoven
with a wireweave
bond pattern. Suitably, the spunbond material is available from Kimberly-Clark
Corporation,
located in Rosweil, GA. The outer cover 13 has a weight from about 0.3 oz. per
square yard (osy)
to about 2.0 osy and alternatively about 0.6 osy. The outer cover 13 of the
underpant maybe
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printed, colored or decoratively embossed. The outer cover 13 has a pore size
that readily allows
the passage therethrough of air, sweat, perspiration due to the breathability
of the material. The
outer cover 13 may be selectively embossed or pertorated with discrete slits
or holes extending
therethrough.
Referring to Figures 1a, 2a, and 3, an edge 60 of front body portion 14 is
assembled with an
edge 62 of the back body portion 15 to form a seal or side seam 84. Similarly,
an edge 66 of the
front body portion 14 is assembled with an edge B8 of the back body portion 15
to form a seal or
side seam T0. The front body portion 14 and the back body portion 15, when
assembled form a
waist opening 20 for putting on and taking off the underpant 12. The waist
opening 20 is
surrounded at least in part by waist portion elastic 22 including from between
1 and 40 elastic
strands, threads, ribbons, or bands of elastic matertal. The waist portion
elastic 22 is stretched and
attached to the body portions 14 and 15. The waist portion elastic 22 may also
be placed in the
front and back waist edge portions 44 and 45. (in other embodiments, the waist
portion elastic 22
may be contained only in the front body portion 14 or only in the back body
portion 15). The waist
portion elastic 22 are released after attachment to produce waist portion
folds, gathers, or pleats
24 (shown in Figures 4 and 5) to allow expansion of the waist opening 20 and
the body portions 14
and 15 so that the underpant 12 can fd various sized individuals.
Because users of this invention generally prefer a brief style underpant, the
front waist edge
portion 44 of the underpant 12 preferably comes to the navel and even around
the wearer's waist.
Having the unde~pant 12 at this height and then drawing in either or both
waist portions 14 and 15
with the waist portion elastic 22 provides a snug fit. Attemative underpant
styles may include bikini
(e.g. regular leg cut and french leg cut) and hipster (e.g. regular leg cut or
french leg cut).
In some embodiments, the waist opening 20 is surrounded by waist elastic 21
including at
between 1 and 10 strands, ribbons, or bands of elastic materials that are
stretched and attached to
the front waist edge portion 44 and/or the back waist edge portion 45. (See
Figures 5 and T.) (In
other embodiments, the waist elastic 21 may be contained only in the front
waist edge portion 44
or in the back waist edge portion 45.) The waist elastic 21 is released after
attachment to produce
waist folds, gathers, or pleats 25 to allow expansion of the waist opening 20
so that the underpant
12 can fit various sized individuals. Using waist elastic 21 having a
different tension or elongation
than the tension or elongation used in the waist portion elastic 22 can
provide a better fitting
underpant 12.
Referring again to Figure 1a, the front body portion 14 and the back body
portion 15
together with the crotch portion 18 forms leg openings 28 and 30,
respectively, which are generally
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i~VO 99/Z5296 PCTNS98/24544 _ _.
circular or oval in shape. The leg openings 28 and 30 are each surrounded at
least in part by leg
elastics 32, 33, 34, and 35, resped'rvely. The front leg elastics 32 and 33
are stretched and
attached to the front body portion 14, back leg elastics 34 and 35 are
stretched and attached to the
back body portion 15 and the crotch elastics 3T and 39 are stretched and
attached to the crotch
portion 18. The leg and crotch elastics 32, 33, 34, 35, 3T, and 39 ase
released after attachment to
produce leg gathers (also referred to as folds or pleats) 36 to allow
expansion of the !eg openings
28 and 30 to frt various sized legs.
The front body portion 14 is usually divided into a front upper body portion
40 and a front
lower body portion 42. (See Figures 1a, 2a, and 3.) Similarly, the back body
portion 15 is divided
into a back upper body portion 41 and a back lower body portion 43. The front
and back upper
body portions 40 and 41 are preferably designed to include waist portion
elastic 22 which is
capable of stretching to allow the wearer to put on the underpant 12 and then
readily contracting
and conforming to the wearer's body. This ensures a close or snug fit to
different body shapes and
sizes. The waist portion elastic 22 is positioned on both the front and the
back upper body portions
40 and 41, respectively, at positions between the waist opening 20 and the leg
openings 28 and
30, so that the underpant 12 fits the wearer better, particularly around the
body. The front and
back lower body portions 42 and 43 do not necessarily require waist portion
elastic 22. The basis
weight of the laminate comprising the outer cover 13, the bodyside liner 80,
and waist portion
elastic 22 may be as high as 5 osy.
The crotch portion 18 of the underpant 12 consists of an absorbent barrier
composite 46.
(See Figure 1 a.) The absorbent barrier composfte 46 further consists of a
liquid barrier 48, a
substantially liquid pervious topsheet layer 49, and an absorbent core 50
sandwiched between the
liquid barrier 48 and the topsheet layer 49. The liquid barrier 48 and the
topsheet layer 49 are
desirably longer and wider than the absorbent core 50, so that the peripheries
of the liquid barrier
48 and the topsheet layer 49 form margins which may be sealed together using
ultrasonic bonds,
thermal bonds, adhesives, or other suitable means. In this sealed area, the
crotch elastics 3T and
38 may be incorporated between the liquid banter 48 and the topsheet layer 49.
The absorbent
core 50 may be attached to the liquid bartier 48 andlor the topsheet layer 49
using ultrasonic
bonds, adhesives, or other suitable means. (See Figures 1a, 8, and 8.)
The absorbent barrier composite 46 may also include additional components to
assist in the
acquisition, distribution, and storage of body exudates. For example, the
absorbent barrier
composite 46 may include a transport layer, such as described in U.S. Patent
4,798,603 issued
January 17, 1989, to Meyer et al., or a surge management layer, such as
described in European
Patent Application EP 0 539 703 A1, published May 5, 1993, which patent and
application are
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incorporated herein by reference. Such layers are also referred to as
acquisitioNdistribution
layers.
The absorbent barrier composite 46 can be constructed by supplying topsheet
layer 48 and
liquid barrier 48 materials and sandwiching an individual absorbent core 50
between the liquid
bartier 48 and the topsheet layer 49. The side and end peripheries of the
liquid bartier 48 and the
topsheet layer 48 outward of the absorbent core 50 can be joined with the
crotch portion 18, the
front body portion 14, and the back body portion 15 and sealed together. The
absorbent barrier
composite 48 may optionally be T-shaped, i-shaped, oval-shaped, hourglass-
shaped, rectangular
shaped, or irt~egulariy-shaped.
The absorbent core 50 can comprise a coform material composed of a mixture of
csllulosic
fibers and synthetic polymer fibers. For example, the coform material may
comprise an afrlaid
blend of cellulosic wood fibers and meltblown polyolefin fibers, such as
polyethylene or
polypropylene fibers. Absorbent core 50 can comprise only coform, a
combination of
superabsorbent materials and cofortn, coform with other absorbent or non-
absorbent materials
including an acquisitioNdistribution layer, or any combination thereof.
The coform material may comprise an airlaid blend of cellulosic wood fibers
and meltblown
polyolefin fibers, such as polyethylene or polypropylene fibers, or may
comprise an air-formed batt
of cellulosic fibers (i.e., wood pulp fluff). Optionally, the absorbent core
50 may be treated with a
surfactant to aid in liquid acquisition when in a dry environment. In
particular embodiments of the
invention, the absorbent core 50 has a bulk thickness of not more than about
40 mm when dry.
The hydrophilic fibers and polymer strands may be provided in a fiber to-
polymer ratio which is
greater than 20:80, for example between about 80:40 and about 98:2 and,
desirably between about
80:20 and about 90:10. In coform material containing super absorbent
materials, the fiberlhigh
absorbency material ratio is between about 90:10 to about 50:50, and desirably
between about
80:40 to about 65:35. High absorbency materials are discussed below.
Organic high-absorbency materials can include natural materials, such as
pectin, guar gum
and peat moss, as well as synthetic materials, such as synthetic hydrogel
polymers. Such
hydrogel polymers may include, for example, carboxymethylcellulose, alkali
metal salts of
polyacrylic acids, polyacrylamides, polyvinyl alcohol, ethylene malefic
anhydride copolymers,
polyvinyl ethers, hydroxypropyl cellulose, polyvinyl morpholinone, polymers
and copolymers of
vinyl sulfonic acid, polyacrylates, polyacrylamides, polyvinyl pyridine or the
like. Other suitable
polymers can include hydrolyzed acrylonitrile grafted starch, acrylic acid
grafted starch, and
isobutylene malefic anhydride copolymers, and mixtures thereof.
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The hydrogei polymers are desirably sufficiently cross-linked to render the
materials
substantially water-insoluble. Cross-linking may, for example, be by
irradiation or by covalent,
ionic, van der Waals or hydrogen bonding. Suitable materials are available
from various
commercial vendors, such as Dow Chemical Company, Hoechst-Celanese Corporation
and Allied-
Colloid. Typically, the high-absorbency material is capable of absorbing at
least about 15 times its
weight in water, and desirably is capable of absorbing more than about 25
times its weight in water.
The high-absorbency material can be distributed or otherwise incorporated into
the
absorbent core 50 employing various techniques. For example, the high-
absorbency material can
be substantially uniformly distributed among the fibers comprising the
absorbent core 50. The
materials can also be non-uniformly distributed within the absorbent core 50
fibers to form a
generally continuous gradient with either an increasing or decreasing
concentration of
high-absorbency material, as determined by observing the concentration moving
inward from the
liquid barrier 48. Alternatively, the high-absorbency material can comprise a
discrete layer
separate from the fibrous material of the absorbent core 50, or can comprise a
discrete layer
integral with the absorbent core 50.
The absorbent core 50 may also include a wrap layer 100 to help maintain the
integrity of
the fibrous core. (See Figures 8 and 9.) This wrap layer 100 may comprise a
cellulosic tissue or
spunbond, mettblown or bonded-carded web material composed of synthetic
polymer filaments,
such as polypropylene, polyethylene, polyesters or the like or natural polymer
filaments such as
rayon or cotton.
Preferably, the thickness of the absorbent core 50 is less than about 45 mm.
The thickness
of the absorbent core 50 may range from about 4 mm to about 40 mm. Preferably,
the thickness
ranges from about 5 mm to about 30 mm with a thickness having a most
prefert~ed range from
about 8 mm to about 20 mm. The thickness is measured on a 4 inch (102 mm)
smooth unbuckled
square sample (elastics removed) with a Mitutoyo Digamatic Indicator using a 3
inch (78 mm)
diameter acrylic platen and assembly to produce a pressure of 0.05 psi.
The absorbent core 50 should have a liquid capacity great enough to absorb
discharges
from about 100 grams to about 1500 grams. The absorbent core 50 should
preferably have a
capacity (described below) and a thickness preferably less than about 25 mm,
thus providing a
non~bulky and flexible fit. The capacity of the absorbent core 50 should have
a total capacity of
about 200 grams to about 1000 grams. Preferably, the absorbent core 50 should
have a total
capacity of at least about 300 grams and nat more than about 800 grams. More
preferably, the
total capacity of the absorbent core 50 should be from about 400 grams to
about 800 grams.
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The total capacity of the absorbent core 50 is determined using the absorbent
barrier
composite 46 of the underpant 12 and the outer cover 13. The saturated
retention capacity is a
measure of the total absorbent capacity of an absorbent garment, in this case
underpant 12. The
saturated retention capacity is determined as follows. The underpant 12 to be
tested, having a
moisture content of less than about 7 weight percent, is then weighed and
submerged in an excess
quantity of the room temperature (about 23° C) saline solution
described below. The material is
allowed to remain submerged for 20 minutes. After 20 minutes the underpant 12
is removed from
the saline solution and placed on a Teflon T~ coated fiberglass screen having
0.25 inch openings
(commercially available from Taconic Plastics Inc., Petersburg, N.Y.) which,
in turn, is placed on a
vacuum box and covered with a flexible rubber dam material. A vacuum of 3.5
kilopascals (0.5
pounds per square inch) is drawn in the vacuum box for a period of 5 minutes.
The underpant 12
is weighed. The amount of fluid retained by the material being tested is
determined by subtracting
the dry weight of the underpant 12 from the wet weight of the underpant 12
(after application of the
vacuum) and is reported as the saturated retention capacity in grams of fluid
retained.
The saline solution is a solution of about 0.9 percent sodium chloride by
weight. A suitable
product is S/PT"~ Certified Blood Saline commercially available from Baxter
Diagnostics in McGaw
Park, Illinois.
In construction of the absorbent barrier composite 46, the liquid barrier 48
should retard the
movement of the liquid through the absorbent barrier composite 48 by making
the liquid barrier 48
resistant to penetration normally encountered under wearing cond'ttions. The
absorbent barrier
composite 46 may be rendered liquid impermeable by any method well known in
the art such as
coating the absorbent core 50 or by securing a separate liquid impermeable
material to the
absorbent core 50. The liquid barrier 48 may comprise a thin, liquid
impervious web or sheet of
plastic film such as polyethylene, polypropylene, polyvinyl chloride or
similar material. Alternately,
the liquid barrier 48 may comprise a nonwoven, fibrous web which has been
suitably constructed
and arranged to have low liquid perviousness. Still alternately, the liquid
barrier 48 may comprise
a layered or laminated material, such as a thermally bonded plastic film and
nonwoven web
composite. Alternatively, the liquid barrier 48 consists of a liquid
impervious film or foam which is
pervious to water vapor under normal wearing conditions. More preferred, the
liquid barrier 48 has
a water vapor transmission rate of at least about 1000 grams/m2/day measured
by ASTM E98-92.
One example of a suitable film is a 39.4 grams per square meter microporous
film produced by
Mitsui and sold by Consolidated Thermoplastics (C~ under the tradename of
ESPOIR~ N-TAF-
CT.
The liquid barrier 48 desirably comprises a material that is formed or treated
to be fluid
impermeable. Alternatively, the liquid barrier 48 may comprise a fluid
permeable material and
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other suitable means (not shown), such as a fluid impermeable layer associated
with the absorbent
barrier composite 46 (or the absorbent core 50), may be provided to impede
fluid movement away
from the absorbent barrier composite 46 (or the absorbent core 50). The liquid
barrier 48 may
comprise a single layer of material or a laminate of two or more separate
layers of material.
Suitable materials for the liquid barrier 48 inGude thermoplastic films,
wovens, nonwovens,
laminates of films, wovens, and/or nonwovens, foams, or the like. For example,
the liquid barrier
48 may comprise a thin, substantially fluid impermeable web or sheet of
plastic film such as
polyethylene, polypropylene, ar similar material. One suitable material for
the liquid barrier 48 is a
0.028 millimeter (mm) thick polyethylene film with a systematic matte embossed
pattern and that
has been corona treated on both sides. The terms "fluid impermeable" or
"liquid impermeable' as
used herein to describe a layer or laminate means that fluid or liquid such as
urine will not pass
through the layer or laminate under ordinary use conditions in a direction
generally perpendicular
to the plane of the layer or laminate at the point of fluid (or liquid)
contact.
The liquid barrier 48 is needed to prevent liquid strike through to the outer
clothing when
discharge occurs onto the absorbent bartier composite 46 of the underpant 12.
The liquid barrier
48 is located on the inside of the outer cover 13 in the crotch portion 18 and
consists of a liquid
impervious film such as polyethylene. Use of only the film (without the outer
cover 13) would be
hot and uncomfortable, may not be durable enough to withstand extended periods
of wear. The
absorbent core 50 may be associated with a liquid barrier 48 which may or may
not inGude elastic
characteristics.
The absorbent barrier composite 46 includes a substantially fluid impermeable
liquid barrier
48, a fluid (or liquid) permeable topsheet layer 48 superposed on the outer
cover 13. (See Figures
1a, 8, and 9.) The absorbent core 50 is sandwiched between the liquid barrier
48 and the topsheet
layer 49. (See Figures 1a, 8, and 9.) The liquid barrier 48 and the topsheet
layer 49 are desirably
longer and wkier than the absorbent core 80. The topsheet layer 49 is designed
to be positioned
toward the wearer and is referred to as the body-facing surtace 16.
Conversely, the liquid barrier
48 is designed to be positioned toward the outer cover 13 and the outer
clothing of the wearer and
is referred to as the garment-facing surtace 23.
The absorbent core 50 comprises materials adapted to absorb and retain urine,
menses,
blood, or other body excrement. The absorbent core SO may comprise various
natural or synthetic
absorbent materials, such as cellulose fibers, surtadant treated meltblown
fibers, wood pulp fibers,
regenerated cellulose or cotton fibers, a blend of pulp and other fiber, or
the like. One such
material is a coform material which is composed of a mixture of cellulosic
fibers and synthetic
polymer fibers. The absorbent core 50 may also inGude compounds to increase
its absorbency,
such as 0 - 95 weight percent of organic or inorganic high-absorbency
materials, which are
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CA 02309585 2000-OS-08
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typically capable of absorbing at least about 15 and desirably more that 25
times their weight in
water. Suitable high-absorbency materials are described in U.S. Patents
4,899,823 issued October
13, 1987, to Kellenberger et at. And 5,147,343 issued September 15, 1992 to
Kellenberger, which
are incorporated herein by reference. High absorbency materials are available
from various
commercial vendors, such as Dow Chemical Company, Hoechst Celanese
Corporation, and Allied
Colloids, Inc. The absorbent core 50 may also include tissue layers or
acquisition or distribution
layers to help maintain the integrity of fibrous absorbents or transport
fluids.
One suitable absorbent core 50 is separately illustrated in Figure 8 and
comprises a fluid
slorage layer 51 and an aoquisitioNdistribution layer 62. The fluid storage
layer 51 has two
sections. The 1 st section, the acquisition section (not shown), has a greater
fluid capacity per unit
area with 479 GSM fluff and 280 GSM SAP. The acquisition section is centered
in the area where
urine will be insulated by the user. The second section (not shown) has lower
capacity per unit
area, 215 GSM fluff and 117 GSM SAP.
The acquisition/distribution layer 52 is disposed on the fluid storage layer
51 toward the
body-facing surface 16 of the absorbent core 50 to help decelerate and diffuse
surges of fluid that
may be introduced into the absorbent core 50. The acquisitioNdistribution
layer 52 may comprise
a through-air bonded carded web composed of a blend of 40 percent 8 denier
polyester fibers,
commercially available from Hoechst Celanese Corporation, and 80 percent 3
denier
polypropylene/polyethylene sheath core bicomponent fibers, commercially
available from the
Chisso Corporation, with an overall basis weight ranging of from about 50 gsm
and about 120 gsm.
Alternative acquisitioNdistribution materials are described in U.S. Patent
5,192,806 issued March
9, 1993, to D. Proxmire et al.; U.S. Patent 5,486,188 issued January 23, 1996
to Etlis et al.; U.S.
Patent 5,490,846 issued February 13, 1998 to Ellis et al.; and U.S. Patent
5,509,915 issued April
23, 1998 to Hanson et al.; the disclosures of which are hereby incorporated by
reference. The
illustrated acquisitioNdistribution layer 52 is rectangular with a length of
about 191 mm. And a
width of about 45 mm. The acquisition/distribution layer 52 can vary in shape
and size as
disclosed for the absorbent core 50 and the absorbent banier composite 46.
In other embodiments of the present invention, the absorbent barrier composite
4B includes
a single layer absorbent core 50. The absorbent core 50 comprises materials
adapted to absorb
and retain urine, menses, blood or other body excrement. The absorbent core 50
may comprise
various natural or synthetic absorbent materials, such as cellulose fibers,
surfactant treated
meftblown fibers, wood pulp fibers, regenerated cellulose or cotton fibers, a
blend of pulp and other
fibers, or the like. One such material is coform material which is composed of
a mixture of
celiulosic fibers and synthetic polymer fibers. The absorbent core 50 may also
include compounds
to increase its absorbency, such as 0 - 95 weight percent of organic or
inorganic high-absorbency
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materials, which are typically capable of absorbing at least about 15 and
desirably more than 25
times their weight in water. Suitable high-absorbency materials are described
in U.S. Patents
4,899,823 issued October 13, 1987, to Kellenberger et at.; and 5,147,343
issued September 15,
1992, to Kellenberger, which are incorporated herein by reference. High-
absorbency materials are
available from various commercial vendors, such as Dow Chemical Company,
Hoechst Celanese
Corporation, and Allied Colloids, Inc.
One suitable absorbent core 50 for the underpant 12 is separately illustrated
in Figure 8 and
comprises a fluid storage layer 51. The fluid storage layer 61 comprises an
air laid mixture of
about 470 gsm wood pulp fibers and about 305 gsm high-absorbency materials
that is sandwiched
or wrapped between 19 gsm cellulose tissues (wrap layers 100). The fluid
storage layer 51 is
desirably embossed using a matched malelmale embossing roll. The typical
absorbent core 50 is
hourglass shaped with a length of between about 17 inches (430 mm) and about
21 inches (530
mm) and a width of between about 2.5 inches (84mm) and about 3.5 inches (120
mm). The
absorbent core 60 desirably has a thickness dimension of less than about 20
mm, particularly less
than about 10 mm.
The topsheet layer 48 is formed of a fluid permeable material so that fluid
waste, and
possibly semi-solid waste as well, can pass through to the absorbent core 50
and be absorbed by
the absorbent barrier composite 46 (or absorbent core 50). A suitable topsheet
layer 48 may be
comprised a nonwoven web, a spunbond, mettblown or bonded-carded web composed
of synthetic
polymer filaments or fibers, such as polypropylene, polyethylene, polyesters
or the like, a
perforated film, or a web or natural polymer filaments or fibers such as rayon
or cotton. In
addition, the topsheet layer 49 may be treated with a surfactant to aid in
fluid transfer. In one
particular embodiment, the topsheet layer 48 comprises a nonwoven, spunbond
web of sheath
core bicomponent filaments with 50 percent polyethylene and 50 percent
polypropylene having a
basis weigh of about 20 grams per square meter (gsm). The fabric is surface
treated with a
surfactant commeroiaily available from Union Carbide Chemicals and Plastics
Company, Inc., of
Danbury, Connecticut, U.S.A. under the trade designation TRITON X-102. As used
herein, the
term 'fabric' refers to all of the v~roven, knitted and nonwoven fibrous webs.
The term "nonwoven
web' means a web of material that is formed without the aid of a textile
weaving or knitting
process.
The width of the crotch portion 18 between the crotch elastics 37 and 38
should be wide
enough to accommodate the absorbent core 50 between the side edges 17 and 18
of the crotch
portion 1 a without having the absorbent core 50 obstruct the crotch elastics
37 and 38 and
ultimately the leg elastics 32, 33, 34, and 35. This allows the crotch
elastics 37 and 39 to contract
and draw up the sides of the crotch creating a bucket with wails of the
topsheet layer 48 and liquid
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barrier 48 to keep bodily exudates from leaking out of the product and to
accommodate more sizes
of individuals.
The width of the crotch portion 18 should not be so wide as to seem bulky or
uncomfortable,
but a suitable width is at least about 2.5 inches (64 mm) between the crotch
elastics 37 and 39.
The width is advantageously ranges from about 2.5 inches (64 mm) to about 8.0
inches (152 mm).
Typically the width of the crotch portion 18 between the crotch elastics 3T
and 39 ranges from
about 3.5 inches (89 mm) to about 5 inches (127 mm). Preferably, the width so
defined is about
4.25 inches (108 mm).
The crotch portion 18 is at least about 0.25 inch (6 mm) wider than the width
of the
absorbent core 50. The crotch portion 18 is from about 0.25 inch (8 mm) to
about 4 inches (102
mm) wider than the absorbent core 50. Typically the crotch portion 18 is from
about 0.5 inch (13
mm) to about 3 inches (76 mm) wider than the absorbent core 50 and more
typically from about
0.5 inch (13 mm) to about 2 inches (51 mm) wider. Preferably, each of the
crotch elastics 37 and
38 are from about 0.2 inch (5 mm) to about 0.8 inch (20 mm) wide. More
preferably, the width of
each crotch elastics 37 and 39 is from about 0.2 inch (5 mm) to about 0.4 (10
mm). The overall
width of the crotch portion 18 includes the width between the crotch elastics
37 and 39, the width of
the crotch elastics 37 and 39 and the ruffle material outside the crotch
elastics 37 and 39 to the
edge of the leg openings 28 and 30.
Preferably, ruffle material on the edge of the leg openings 28 and 30 outside
the leg and
crotch elastics 32, 33, 34, 35, 37, and 39 is less than about 0.5 inch (13
mm). More preferably, the
ruffle material is less than about 0.125 inch (3 mm). It is most desirable to
eliminate the ruffle
material from the edge of the leg openings 28 and 30.
The width of the absorbent barrier composite 46 is sized in relation to the
width of the crotch
portion 18. The width of the composite 4B is at least the width of the crotch
portion 18 between the
crotch elastics 37 and 39. Preferably, the width is equivalent to the width of
the crotch portion 18.
The overall length of the absorbent barrier composite 46 should be adequate to
extend
beyond the ends of the absorbent core 50 to help prevent liquid strike through
at these points when
sleeping or sitting. This overall length is at least about 12 inches (305 mm)
thus extending beyond
the crotch portion 18 along the longitudinal ceMeriine A-A of the underpant
12. Aftematively, the
length should be in the range of about 12 inches (305 mm)to about 30 inches
(762 mm), more
typically ranging from about 15 inches (381 mm) to about 23 inches (584 mm). A
common range
is from about 17 inches (432 mm) to about 21 inches (533 mm) in length.
Optimally, the length of
the composite 46 is about 19 inches(483 mm).
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The width of the absorbent barrier composite 46 extending beyond the crotch
portion 18
should be at least as wide as the width of the crotch portion 18. The width of
the absorbent barrier
composite 46 could be narrowed beyond the crotch portion 18 but may compromise
the leakage
containment. Typically the width of the absorbent barrier composite 46 is
widened beyond the
crotch portion 18. The width of the absorbent barrier composite 46 extending
beyond the crotch
portion 18 is from about 2.5 inches (84 mm) to about 12 inches (305 mm),
alternatively from about
4.0 inches (102 mm) to about 10 inches (254 mm). A common range is from about
7 inches (178
mm) to about 9 inches (229 mm). Optimally, the width is about 8 inches (203
mm).
The present invention contemplates various shapes of the absorbent barrier
composite 48.
One preferred composite has a non-rectangular shape such as an hourglass or I-
beamed shaped
absorbent barrier composite 46 which provide extensive coverage in the seat of
the finished
underpant 12. Another preferred absofient barrier composite 46 embodiment is
rectangular in
shape with rounded ends. The essentially rectangular shaped absorbent barrier
composite 4B (i.e.
an hourglass shape) is more preferred since it can be squared off at the ends
to provide a
smoother appearance in the back of the underpant 12 while providing a more
comfortable body-
contouring fit.
Referring to Figures 1a ~ c, 2a - b, 3, and 6, the waist portion elastic 22
are shown covered
with a body liner 80. The body liner 80 consists of a nonwoven or other soft
material for contacting
the wearer's skin. The body liner 80 is described in more detail below. In
other embodiments, at
least a portion of the waist portion elastic 22 may be covered by the
absorbent barrier composite
46. Referring to Figures 3 and 4, the leg elastics 32, 33, 34, and 35 are
shown covered by the
body liner 80. In Figure 1b, the crotch elasttcs 37 and 39 are shown
sandwiched between the
topsheet layer 49 and the liquid barrier 48. In alternative embodiments, the
crotch elastics 37 and
39 can be sandwiched between the outer cover 13 and the liquid barrier 48.
Depending on the size
and shape of the absorbent barrier composite 46, at least a portion of the leg
elastics 32, 33, 34,
and 35 may be covered by the absorbent barrier composite 46.
Referring to Figures 5 and 7, the waist elastic 21 are shown in another
embodiment as
covered with a waist liner 26. The waist elastic 21 could also be covered with
the body liner 80.
Referting to Figures 5 and 7, the leg elastics 32 and 34 are shown covered by
a leg liner 38.
Depending on the size and shape of the absorbent barrier composite 46, at
least a portion of the
leg elastics 32, 33, 34, and 35 may be covered by the absorbent barrier
composite 46. In Figure
1a, the crotch elastics 3T and 39 are shown covered by the absorbent barrier
composite 46 as the
crotch elastics 3T and 38 are sandwiched between the outer cover 13 and the
absorbent barrier
composite 46. Referring to Figure 7, the waist portion elastic 22 are shown
covered with a body
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-wo 99ns296 Pcrius9sn4saa . .
liner 80. The body liner 80 consists of a nonwoven or other soft material for
contacting the
wearers skin. In other embodiments, at least a portion of the waist portion
elastic 22 may be
covered by the absorbent barrier composite 48.
The body liner 80 is compliant and soft feeling to the wearer. The body liner
80 may be any
soft, flexible, porous sheet which is liquid pervious, permitting liquids to
readily penetrate into its
thickness, or impervious, resistant to the penetration of liquids into its
thickness. A suitable body
liner 80 may be manufactured from a wide range of materials, such as natural
fibers (e.g., wood or
cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers) or
from a combination of
natural and synthetic fibers or reticulated foams and apertured plastic films.
There are a number of manufacturing techniques which may be used to
manufacture the
body liner 80. For example, the body liner 80 may be woven or nonwoven web or
sheet such as a
spunbond, meltblown or bonded-carded web composed of synthetic polymer
filaments, such as
polypropylene, polyethylene, polyesters or the like, or a web of natural
polymer filaments such as
rayon or cotton. The bonded-carcied web may be thermally bonded or sprayed
with a binder by
means well known to those skilled in the fabric art. Suitably, the body liner
80 is a nonwoven
spunbond. Ideally, the body liner 80 is a spunbond polypropylene nonwoven with
a wireweave
bond pattern. Suitably, the spunbond material is available from Kimberly-Clark
Corporation,
located in Roswell, GA. The body liner 80 has a weight from about 0.3 oz. per
square yard (osy) to
about 2.0 osy and alternatively about 0.6 osy. The body liner 80 of the
underpant maybe printed,
colored or decoratively embossed. The body liner 80 has a pore size that
readily allows the
passage therethrough of air, sweat, perspiration due to the breathability of
the material. The body
liner 80 may be selectively embossed or pertorated with discrete slits or
holes extending
therethrough.
The position and the shape of the leg openings 28 and 30 are important to
avoid tightness in
the crotch and groin area of the wearer, to obtain adequate buttocks coverage,
and to prevent the
underpant 12 from tilting forward, i.e. tilting such that the front waist edge
dips lower in relationship
to the back waist edge. Figure 1a illustrates the most preferred design for
leg fit and buttocks
coverage. The shape of the curve across the front edges T2 and T4 of the leg
openings 28 and 30
may have an impact on the fd of the underpant 12. If the curve is too deep,
the underpant 12 will
shift downward and backwarct resulting in a short front waist, increased back
length and bagginess
in the seat of the underpant 12. This causes the underpant 12 to appear tilted
when worn as
evidenced by an unevenness around the waist of the wearer, resulting in
tightness along the front
edges T2 and T4 of the leg openings 28 and 30 and reducing the comfort in the
fit.
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The structures of the leg openings 28 and 30 are important to the correct
functioning of the
underpant 12. With the underpant 12 laid out flat as in Figure 1a, the
majority (at least 51%) of
the back edges T6 and 78 of the back portions 82 and 84 of the leg openings 28
and 30
respectively preferably fortrts a substantially linear line. More preferably,
the back edges 78 and
78 of the back portions 82 and 84 of the leg openings 28 and 30 are
substantially linear for a
length, D, of at least about 70% of the length of the entire back portions 82
and 84. The straight
section D of the back edges 76 and TS of the back portions 82 and 84 of the
leg openings 28 and
30 should form an acute angle with the longitudinal centerline, A-A, of the
underpant 12.
Preferably, the line, O, forms an angle, a, with the centerline A-A of the
underpant 12 of between
about 45° and about 89°, more preferably between about
55° and about 87° and most preferably
between about 81° and about 78°. If a shallow curve (a curve
having a radius of at least 6 inches)
defines the back edges T8 and 78 of the back portions 82 and 84 of the leg
openings 28 and 30,
two points are selected along the curve, one point is positioned at about 25%
of length of the curve
and the other point is positioned at about 75% of the length of the curve. A
line drawn between the
two points is used to determine the a angle formed with the centerline A-A of
the underpant 12.
The back edges 7B and T8 forming acute angles with the longitudinal centerline
as disclosed
reduce bunching and shifting of the absorbent core 50 during use, ensuring a
better contouring to
the body and comfortable fit. Such angles help the underpant 12 to under cut
the buttocks,
improving fit and reducing leakage. it is understood that because the leg
elastics 34 and 35
closely follow the back edges 78 and 76 respectively, the references to the
back edges T8 and 76
can be read to describe the leg elastics 34 and 35.
The majority (at least 51%) of the front edges 72 and T4 of the front portions
86 and 88 of
the leg openings 28 and 30 include lengths p, preferably forming straight
lines. More preferably,
the lengths of front edges T2 and 74 (~) of the leg openings 28 and 30 are
substantially linear for at
least about 70% of the length of the front portions 86 and 88 of the leg
openings 28 and 30. The
substantially linear section p of the front edges 72 and T4 of the front
portions of the leg openings
28 and 30 should forth an angle x with the centerline of the underpant 12 of
between about 62° and
about 99°, more preferably between about 74° and about 91
°, and most preferably about 85°. The
front edges T2 and T4 forming an angle with the centerline as disclosed reduce
bunching and
shifting of the absorbent core 60 during use, ensuring a better contouring to
the body and
comfortable fit. If a shallow curve (a curve having a radius of at least 6
inches) defines the front
edges T2 and 74 of the front portions 88 and 88 of the leg openings 28 and 30,
two points are
selected along the curve, one point is positioned at about 25% of length of
the curvy and the other
point is positioned at about 75% of the length of the curve. A line drawn
between the two points is
used to determine the x angle formed with the centerline of the underpant 12.
While front edges
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T2 and T4 forming angles of 90° can be used, angles at least slightly
greater or less than 90°
provide an underpant 12 having a comfortable fit during movement. It is
understood that because
the leg elastics 32 and 33 closely follow the front edges 72 and T4
respectively, the references to
the front edges 72 and 74 can be read to describe the leg elastics 32 and 33.
likewise, the shape of the curve in the crotch portion 18 is important. The
majority of the
side edges 1T and 19 of the crotch portion 18 include lengths E, preferably
forming curved
(arcuate) lines. If the curve is too shallow or straight (especially at the
ends of the crotch elastics
37 and 39), tightness may be experienced at the inner groin area and gapping
in the fit of the
underpant 12 as the underpant 12 does not follow the contour of the wearer's
leg, resulting in
leakage. The preferred narrow crotch width having shallow curves may also
reduces the coverage
of the buttocks. To compensate for such redudion, the back leg edges T8 and 78
on the back
portions 82 and 84 are preferably adjusted downward, increasing the a angle.
The curve between
the side edges 17 and 19 of the crotch portion 18 and the back portions 82 and
84 of the leg
openings 28 and 30 should start slightly in front of centerline B-B of the
underpant 12, see
Figure 1a. This allows the back leg elastics 34 and 35 to be positioned below
the lower edge of
the buttocks and helps prevent the underpant 12 from riding up when walking.
This means that the
curved crotch portion E of the leg openings 28 and 30 are entirely forward of
the underpant 12
centerline B-B. It is understood that because the crotch elastics 3T and 39
closely follow the edges
17 and 19 respedively, the references to the edges 17 and 19 can be read to
describe the leg
elastics 3T and 39.
While the leg elastics 32, 33, 34, and 35 can be designed to dosely follow the
edge of the
absorbent core 50 outside of the crotch portion 18, moving the leg elastics
32, 33, 34, and 35
away from the absorbent core 50, the absorbent core 50 interters less with the
function of the leg
elastics 32, 33, 34, and 35, providing better gasketing around the leg
openings 28 and 30. In
addition, as absorbent core 50 swells as it absorbs bodily discharges, the leg
elastics 32, 33, 34,
and 35 so positioned are better able to remain in contad with and conformed to
the wearePs body.
In a preferred embodiment, the waist portion and leg elastics 22, 32, 33, 34,
and 35,
respedively, (and in embodiments including waist elastic 21) are attached to
the underpant 12
sandwiched between the outer cover 13 and the body liner 80 in generally a
stretched state by
means known in the art, inGuding ultrasonic bonded, heat/pressure bonded or
adhesively bonded.
The crotch elastics 37 and 38 are sandwiched between the liquid banter 48 and
the topsheet layer
49 of the absorbent barrier composite 46. The crotch elastics 37 and 38 are
typically attached in a
stretched state by means known in the art, including ultrasonic bonded,
heat/pressure bonded or
adhesively bonded. Materials suitable for the elastics include a wide variety
including but not
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limited to elastic strands, yam rubber, flat rubber, elastic tape, film-type
rubber, polyurethane and
elastomeric, tape-like elastomeric or foam polyurethane or formed elastic or
non-elastic scrim.
Suitable material is sold under the name LYCRA~ by the DuPont Company located
in Wilmington,
Delaware. Each elastic may be unitary, mufti-part or composite in construction
before integrating
into the underpant 12.
In an alternative embodiment, the waist portion, leg, and crotch elastics 22,
32, 33, 34, 35,
37, and 38, respectively, (and in embodiments including waist elastic 21) are
attached to the
underpant 12 sandwiched between the outer cover 13 and the body finer 80 in
generally a
stretched state by means known in the art, such as ultrasonic bonded,
heat/pressure bonded or
adhesively bonded. Materials suitable for the elastics include a wide variety
including but not
limited to elastic strands, yam rubber, flat rubber, elastic tape, film-type
rubber, polyurethane and
elastomeric, tape-like elastomeric or foam polyurethane or formed elastic or
non-elastic scrim.
Suitable material is sold under the name LYCtZA~ by the DuPont Company located
in Wilmington,
Delaware. Each elastic may be unitary, mufti-part or composite in
construction.
The portion of the front and back body portions 14 and 15 having waist portion
elastic 22 is
from about 1 inch (25 mm) to about 10 inches (254 mm) wide (perpendicular to A-
A as shown in
Figure 1a). More typically, the portion of the front and back body portions 14
and 15 having waist
portion elastic 22 is from about 3 inches (7t3 mm) to about 8 inches (203 mm)
wide. More typically,
the width ranges from about 6 inches (152 mm) to about 7.5 inches (191 mm). tn
some
embodiments it is desirable to vary the widths of waist portion elastic 22
between the front and
back body portions 14 and 15. If one of the body portions 14 and 15 has a
narrower portion of
waist portion elastic 22, the width ranges between about 1 inch (25 mm) to
about 8 inches (203
mm), more typically from about 3 inches (78 mm) to about 8 inches (152 mm),
and most typically
from about 4 inches (102 mm) to about 5.5 inches (140 mm). The waist portion
elastic 22 is
applied under an elongation of from about 100% to about 400%, more typically
under an
elongation of from about 150°A to about 300°~6, and most
typically under an elongation of from
about 200% 1o about 275%. The underpaM 12 may be constructed such that the
tension of the
waist portion elastic 22 may be a different value in the front body portion 14
as compared to the
tension of the waist portion elastic 22 in the back body portion 15.
The waist portion elastic 22 may comprise threads, strands, ribbons, bands,
film, elastic
nonwovens, or composite. The threads, strands, ribbons, or bands may be
multiple and may be
applied as a composite. The number of pieces of elastic material comprising
the waist portion
elastic 22 ranges from about 1 to about 100, more typically from about 10 to
about 40, and most
typically from about 15 to about 35. Preferably, when the waist portion
elastic 22 are threads, 15
to 40 threads are used as the waist portion elastic 22 and the threads are
spaced from about
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0.0825 inch (1.8 mm) to about 2 inches (51 mm), more preferably from about
0.0825 inch (1.8
mm) to about 0.5 inch (13 mm), and most preferably about 0.25 inch (8 mm)
apart. While the
appearance of the underpant 12 may be enhanced by the close even spacing of
the elastic
material, such as threads, in the waist portion elastic 22, however, the
distance between the pieces
of elastic material can be varied. Such variation can be used in the front and
back waist edge
portions 44 and 45 to give the appearance of a waist band.
in a preferred embodiment, the elastic threads may be made of any suitable
elastomeric
material. One suitable material is spandex such as LYCI~A~ threads available
from DuPont
located in Wilmington, Delaware. Suitable waist portion elastic 22 include
threads having a decitex
(gH OOOOm) of about 100 to about 1200, more typically from about 470 to about
940, and most
typically from about 820 to about 740 for waist portion elastic 22 comprising
from about 15 to
about 35 threads. Adhesive 74, typically applied in a meltblown or swirl
pattern using currently
known technology, is used to bond the waist portion elastic 22 to the outer
cover 13 and the body
liner 80. Preferably the adhesive 74 is applied only to the waist portion
elastic 22. A suitable
adhesive includes, for example, Findley H20» hot melt adhesive which is
available from Ato
Findley Adhesives located in Milwaukee, WI.
In embodiments that include waist elastic 21, the waist elastic 21 is from
about 0.0825 inch
(1.8 mm) to about 2 inches (51 mm) wide. More typically, the front and back
waist edge portions
44 and 45 of the front and back body portions 14 and 15 respectively having
waist elastic 21 is
from about 0.25 inches (8 mm) to about 1.5 inch (38 mm) wide. More typically,
the width ranges
from about 0.5 inches (13 mm) to about 1 inches (25 mm). The waist elastic 21
is applied under an
elongation of from about 15096 to about 300%, more typically under an
elongation of from about
175°~ to about 275°~, and most typically under an elongation of
from about 200°~ to about 250%.
The waist elastic 21 may comprise threads, strands, ribbons, film, elastic
nonwovens, or
composite. The threads, strands, ribbons, or bands may be multiple and may be
applied as a
composite. The number of pieces of elastic material comprising the waist
elastic 21 ranges from
about 1 to about 20, more typically from about 2 to about 10, more typically
from 2 to about 8, and
most typically from about 2 to about 8. Preferably, when the waist elastic 21
are threads, 3 to 8
threads are used as the waist elastic 21 and the threads are spaced from about
0.0825 inch (1.8
mm) to about 1.5 inches (38 mm), more preferably from about 0.0825 inch (1.8
mm) to about 0.25
inch (8 mm), and most preferably about 0.125 inch (3 mm) apart.
The threads may be made of any suitable efastomeric material. One suitable
material is
spandex such as LYCRA~ threads available from DuPont located in Wilmington,
Delaware.
Suitable waist elastic 21 include threads having a decitex (g/10000m) of from
about 100 to about
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1200, more typically from about 470 to about 940, and most typically from
about 820 to about 940
for waist elastic 21 comprising from about 5 to about 10 threads. Adhesive 74,
typically applied in
a meltbiown or swirl pattern using currently known technology, is used to bond
the waist elastic 21
to the outer cover 13 and the body liner 80 or waist liner 28. Preferably the
adhesive 74 is applied
only to the waist elastic 21. A suitable adhesive includes, for example,
Flndley H2098 hot melt
adhesive which is available from Ato Findley Adhesives located in Milwaukee,
WI.
The leg elastics 32, 33, 34, and 35 are from about 0.0825 inch (1.8 mm) to
about 1 inch (25
mm) wide, more typically from about 0.25 inch (8 mm) to about 1 inch (25 mm),
and most typically
from about 0.25 inch (8 mm) to about 0.75 inch (18 mm). The leg elastic 32,
33, 34, and 35 is
applied under an elongation of from about 100% to about 300°~, more
typically under an
elongation of from about 175% to about 275%, and most typically under an
elongation of from
about 200% to about 250%.
The leg elastics 32, 33, 34, and 35 may comprise threads, strands, bands,
ribbons, film,
elastic nonwovens, or composite. The threads, strands, ribbons, or bands may
be multiple and
may be applied as a composite. The number of pieces of elastic material
comprising the leg elastic
32, 33, 34, and 35 ranges from about 1 to about B, more typically from about 2
to about 5, and
most typically from about 3 to about 4. Preferably, when the leg elastic 32,
33, 34, and 35 are
threads, 1 to 8 threads are used as the leg elastic 32, 33, 34, and 36, and
the threads are spaced
from about 0.0825 inch (1.8 mm) to about 0.5 inches (13 mm), more preferably
from about 0.0825
inch (1.8 mm) to about 0.25 inch (8 mm), and most preferably about 0.125 inch
(3 mm) apart.
The threads may be made of any suitable elastomeric material. One suitable
material is
spandex such as LYCRA~ threads available from DuPont located in Wilmington,
Delaware.
Suitable leg elastics 32, 33, 34, and 35 include threads having a decitex
(g/10000m) of from about
470 to about 1200, more typically from about 820 to about 1000, and most
typically from about 740
to about 940 for leg elastics 32, 33, 34, and 35 having comprising from about
3 to about 8 threads.
Adhesive 74, typically applied in a meltblown or swirl pattern using currently
known technology, is
used to bond the leg elastics 32, 33, 34, and 35 to the outer cover 13 and to
the body liner 80, the
absorbent barrier composite 48, or the leg liner 38. Preferably the adhesive
74 is applied only to
the feg elastics 32, 33, 34, and 35. A suitable adhesive includes, for
example, Findley H2098 hot
melt adhesive which is available from Ato Findley Adhesives located in
Milwaukee, Wi.
The crotch elastics 37 and 38 are from about 0.0825 inch (1.8 mm) to about 1
inch (25 mm)
wide, more typically from about 0.25 inch (8 mm) to about 1 inch (25 mm), and
most typically from
about 0.25 inch (8 mm) to about 0.75 inch (18 mm) such as 0.5 inch (13 mm).
The crotch elastic
37 and 39 is applied under an elongation of from about 100°~ to about
300%, more typically under
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an elongation of from about 150% to about 275%, and most typically under an
elongation of from
about 200% to about 250%.
The crotch elastics 37 and 39 may comprise threads, strands, ribbons, bands,
film, elastic
nonwovens, or composite. The threads, strands, ribbons, or bands may be
multiple and may be
applied as a composite. The number of pieces of elastic material comprising
the crotch elastic 37
and 39 ranges from about 1 to about 6, mona typically from about 2 to about 5,
and most typically
from about 3 to about 4. Preferably, when the crotch elastics 37 and 39 are
threads, 1 to 8 threads
are used as the crotch elastics 37 and 39, and the threads are spaced from
about 0.0625 inch (1.6
mm) to about 0.5 inches (13 mm), more preferably from about 0.0625 inch (1.6
mm) to about 0.25
inch (8 mm), and most preferably about 0.125 inch (3 mm) apart.
The threads may be made of any suitable elastomeric material. One suitable
material is
spandex such as I.YCRA~ threads available from DuPont located in Wilmington,
Delaware.
Suitable crotch elastics 37 and 38 include threads having a decitex (g/10000m)
of from about 470
to about 1200, more typically from about 620 to about 1000, and most typically
from about 740 to
about 940 for crotch elastics 37 and 38 comprising from about 3 to about 8
threads. Adhesive 74,
typically applied in a meltblown or swirl pattern using currently known
technology, is used to bond
the crotch elastics 37 and 39 to the outer cover 13 and to the absorbent
barrier composite 46 or
the leg liner 38. Preferably the adhesive 74 is applied only to the crotch
elastics 37 and 39. A
suitable adhesive includes, for example, Findley H2096 hot melt adhesive which
is available from
Ato Findley Adhesives located in Milwaukee, WI.
In one embodiment, to provide a snug fit around the leg openings 28 and 30 and
to draw up
the sides of the crotch portion 18 to form a cradle structure around the
absorbent core 50, the leg
elastics 32, 33, 34, and 35 are applied to the outer cover 13 under an
elongation of about 200% to
about 250%. The crotch elastics 37 and 39 are sandwiched between the liquid
banier 48 and the
topsheet layer 48 under an elongation of about 200%. Preferably, during the
application of the
elastics, the front leg elastics 32 and 33 and the back leg elastics 34 and 35
are elongated to a
different degree and applied to the outer cover 13. In one embodiment, the
front leg elastics 32
and 33 are elongated less than the back leg elastics 34 and 35.
in another embodiment providing a snug fd around the leg openings 28 and 30
and drawing
the sides of the crotch portion 18 up to form a cradle structure around the
absorbent core 50, the
leg elastics 32, 33, 34, and 35 and the crotch elastics 37 and 39 are applied
to the outer cover 13
under an elongation of about 200% to about 250%. Preferably, during the
application of the
elastics, the front leg elastics 32 and 33 and the back leg elastics 34 and 35
are elongated to a
CA 02309585 2000-OS-08
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different degree and applied to the outer cover 13. In one embodiment, the
front leg elastics 32
and 33 are elongated less than the back leg elastics 34 and 35.
In the embodiments having the three segment elastics surrounding each of the
leg openings
28 and 30 (the three segment elastics include front leg elastics 32 and 33,
back leg elastics 34 and
35, and crotch elastics 37 and 38), the front leg elastics 32 and 33 and the
crotch elastics 3T and
39 are elongated less than the back leg elastics 34 and 35. Preferably, the
front leg elastics 32
and 33 and the crotch elastics 37 and 38 are elongated to about 200% and the
back leg elastics 34
and 35 are elongated to about 250%. The three segment elastic system and
differing tensions
allow better fit, less tightness in the groin area, and less bunching of the
crotch portion 18 caused
by high leg elastic retraction. The back leg elastics 34 and 35 are under
higher elongation to help
keep the seat of the underpant 12 from creeping up with movement during use
and stabilizes the
absorbent core 50 from bunching which causes leakage and an uncomfortable fit
of the underpant
12.
In the embodiments having three segments of elastics surrounding each of the
leg openings
28 and 30, the active portions of the crotch elastics 37 and 38 can overlap
with the active portions
of the leg elastics 32, 33, 34, and 35 as shown in Figure 1a (showing such a
configuration with the
crotch elastic 38 and leg elastics 32 and 35). The active portions of the
crotch and leg elastics 32,
33, 34, 35, 3T, and 38 (as well as the waist elastic 21 and the waist portion
elastic 22) is defined as
the portion of the elastic that exerts a contrastive force on the article 1 O.
in Figure 1a, another configuration of the three segments of elastics
surrounding each of
the leg openings 28 and 30 is shown wherein the active portion of the crotch
elastic 3T overlaps
the active portion of the leg elastic 34 but does not overlap the active
portion of the leg elastic 33.
This forms a gap 90 in the elastics surrounding the leg opening 30 in the
front body portion 14.
The gap 80 can range in size from about 3 inches (76 mm) to about 0.125 inches
(3 mm), more
typically from about 2 inches (51 mm) to about 0.25 inch (t3 mm) and most
typically from about 1
inch (25 mm) to about 0.5 inch (13 mm).
The gap 80 provides a more comfortable fit of the underpant 12 in that binding
or chafing
that may result from the leg elastics 32 and 33 and the crotch elastics 37 and
39 during use with
certain body shapes and sizes and activities may be reduced. In addition, the
front lower body
portion 42 is smoothed, providing a more discrete underpant 12.
Another configuration of the three segments of elastics surrounding each of
the leg openings
28 and 30 is shown in Figure 1b wherein the active portion of the crotch
elastic 38 overlaps the
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active portion of the leg elastic 32 but doss not overlap the active portion
of the leg elastic 35.
This forms a gap 92 in the elastics surrounding the leg opening 28 in the back
body portion 15.
The gap 92 can range in size from about 3 inches (78 mm) to about 0.125 inches
(3 mm), more
typically from about 2 inches (51 mm) to about 0.25 inch (f3 mm) and most
typically from about 1
inch (25 mm) to about 0.5 inch (13 mm).
The gap 92 provides a more comfortable fit of the underpant 12 in that binding
or chafing
that may result from the leg elastics 34 and 35 and the crotch elastics 37 and
39 during use with
certain body shapes and sizes and activities may be reduced. In addition, the
back lower body
portion 43 is smoothed, providing a more discrete underpant 12.
Another configuration of the three segments of elastics surrounding each of
the leg openings
28 and 30 is shown in Figure 1 b wherein the active portion of the crotch
elastic 37 does not
overlap the active portion of the leg elastics 33 and 34. This forms gaps 90
and 92 in the elastics
surrounding the leg openings 28 and 30 respectively in the front and back body
portions 14 and 15
respectively. The gaps 80 and 82 can each range in size from about 3 inches
(78 mm) to about
0.125 inches (3 mm), more typically from about 2 inches (51 mm) to about 0.25
inch (6 mm) and
most typically from about 1 inch (25 mm) to about 0.5 inch (13 mm).
The gaps 90 and 92 provide a more comfortable fit of the underpant 12 in that
binding or
chafing that may result from the leg elastics 32, 33, 34, and 35 and the
crotch elastics 37 and 39
during use with certain body shapes and sizes and activities may be reduced.
In addition, the back
lower body portion 43 is smoothed, providing a more discrete underpant 12.
In the embodiment having the two segment elastics surrounding (see Figure 2a)
the leg
openings 28 and 30 (the two segment elastics include front leg elastics 32 and
33, and back leg
elastics 34 and 35), the front leg elastics 32 and 33 are elongated less than
the back leg elastics
34 and 35. Preferably, the front leg elastics 32 and 33 are elongated to about
200%, and the back
leg elastics 34 and 35 are elongated to abut 250%. The two segment elastic
system and differing
tensions allow better fit, less tightness in the groin area, and less bunching
of the crotch portion 18
caused by high leg elastic retraction. The back leg elastics 34 and 35 are
under higher elongation
to help keep the seat of the underpant 12 from creeping up with movement
during use and
stabilizes the absorbent core 50 from bunching which causes leakage and an
uncomfortable fit of
the underpant 12.
Another configuration of the three segments of elastics surrounding each of
the leg
openings 28 and 30 is shown in Figure 1c wherein the active portion of the leg
elastic 32 does not
overlap the active portion of the leg elastic 35. This forms a gap 102 in the
elastic surrounding the
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leg opening 28 at the top of the leg opening 28 in the front body portion 14,
back body portion 15,
or in both the front and back body portions 14 and 15. The gap 102 can range
in size from about 3
inches (78 mm) to about 0.125 inches (3 mm), more typically from about 2
inches (51 mm) to
about 0.25 inch (6 mm) and most typically from about 1 inch (25 mm) to about
0.5 inch (13 mm).
The gap 102 provides a more comfortable fit of the underpant 12 in that
binding or chafing that
may result from the leg elastics 32, 33, 34, and 35 during use with certain
body shapes and sizes
and activities may be reduced. In addition, the gap 102 provides a more
discrete underpant 12 as
"panty lines" are eliminated at the top of the wearer's legs.
In the embodiments having two segments of elastics surrounding each of the leg
openings
28 and 30, the active portions of the leg elastics 32 and 33 can overlap with
the active portions of
the leg elastics 34 and 35 as shown in Figure 2a (showing such a configuration
with the leg elastic
32 and leg elastic 35).
In Figure 2a, another configuration of the two segments of elastics
surrounding each of the
leg openings 28 and 30 is shown wherein the active portion of the leg elastic
33 does not overlap
the active portion of the leg elastic 34. This forms a gap 94 in the elastics
surrounding the leg
opening 30 in the front body portion 14. The gap 94 can range in size from
about 3 inches (78 mm)
to about 0.125 inches (3 mm), more typically from about 2 inches (51 mm) to
about 0.25 inch (8
mm) and most typically from about 1 inch (25 mm) to about 0.5 inch (13 mm).
The gap 94 provides a more comfortable fd of the underpant 12 in that binding
or chafing
that may result from the leg elastics 32, 33, 34, and 35 during use with
certain body shapes and
sizes and activities may be reduced.
Another configuration of the two segments of elastics surrounding each of the
leg openings
28 and 30 is shown in Figure 2a wherein the alive portion of the teg elastic
32 does not overlap
the alive portion of the leg elastic 35. This forms a gap 104 in the elastic
surrounding the leg
opening 28 at the top of the leg opening 28 in the front body portion 14, back
body portion 15, or in
both the front and back body portions 14 and 15. The gap 104 can range in size
from about 3
inches (78 mm) to about 0.125 inches (3 mm), more typically from about 2
inches (51 mm) to
about 0.25 inch (8 mm) and most typically from about 1 inch (25 mm) to about
0.5 inch (13 mm).
The gap 104 provides a more comfortable fit of the underpant 12 in that
binding or chafing that
may result from the leg elastics 32, 33, 34, and 35 during use with certain
body shapes and sizes
and activities may be reduced. In addition, the gap 104 provides a more
discrete underpant 12 as
"panty lines' are eliminated at the top of the wearer's legs.
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In the embodiment having a single segment elastic surrounding (see Figure 3)
the leg
openings 28 and 30 (the single segment elastic include leg elastics 98 and.
98), the leg elastics 98
and 98 are applied under an elongation of from about 100% to about 300%, more
typically under
an elongation of from about 175% to about 275%, and most typically under an
elongation of from
about 200% to about 250%.
The waist portion elastic 22 circumferentially surrounding the body portions
14 and 15 of the
underpant 12 act independently to conform to the contours of various body
types and builds. This
provides a smooth, snug, and comfortable fit within a given hip size range. In
embodiments
having waist elastic 21, the use of higher elongation, closer spacing, and
higher cross-sectional
area in the waist elastic 21 than in the waist portion elastic 22, results in
the underpant 12 having a
rounded shape and good waist fit across a wide range the waist to hip ratios
encountered. The
elongation of the waist portion elastic 22 can be different in the front and
back body portions 14
and 15.
Preferably, in the front body portion 14, the waist portion elastic 22 are
spaced apart from
the front leg elastics 32 and 33. The waist portion elastics 22 in the back
body portion 15 are
spaced apart from the back leg elastics 34 and 35. The distance between the
waist portion elastic
22 and the leg elastics 32, 33, 34, and 35 may range from about 0.125 inch (3
mm) to about 3
inches (7B mm), more typically from about 0.25 inch (8 mm) to about 2 inches
(51 mm), and more
typically from about 0.25 inch (8 mm) to about 1.5 inches (38 mm). The spacing
in the front body
portions 14 and 15 are not required to be the same size. However, the waist
portion elastic 22 in
either or both of the front and back body portions may be adjoin the front or
back leg elastics 32,
33, 34, and 35 respectively. In embodiments where waist elastic 21 are
present, it is preferable
that the waist portion elastic 22 are spaced apart from the waist elastic 21
and the leg elastics 32,
33, 34, and 35.
However, the waist portion elastic 22 in either or both of the front and back
body portions
may adjoin either or both the waist elastic 21 and the leg elastics 32, 33,
34, and 35 wherein the
waist portion elastic 22 adjoin at least a portion of the leg elastics 32, 33,
34, and 35. In a
underpani 12 which is sized to comfortably fit a hip range from about 38
inches (914 mm) to about
45 inches (1143 mm), the waist portion elastic 22 are about 4 inches (102 mm)
wide in the front
body portion 14 and about 8.25 inches (159 mm) wide in the back body portion
15. The waist
portion elastic 22 maybe spaced from about 0.0825 inch (1.8 mm) to about 0.5
inch (13 mm)
apart. Preferably, the waist portion elastic 22 are spaced from 0.0825 inch
(1.8 mm) to about 0.25
inch (8 mm) apart. Most preferably, the waist portion elastic 22 are spaced
about 0.125 inch (3
mm) apart.
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The absorbent barrier composite 48 which extends up the front and/or back body
portions 14
and 15 towarcl the waist opening 20 is conformed to the wearers body by the
force exerted by the
waist portion elastic 22. The transition from the front and back lower body
portions 42 and 43 to
the front and back upper body portions 40 and 41 is thus smoothed.
In embodiments having waist elastic 21, it is desirable that the waist elastic
21 are under a
greater tension per unit width than the waist portion elastic 22 in the upper
body portions 40 and 41
to provide the snug waist fit over the range of waist to hip ratios of the
various body shapes. in the
preferred embodiment, the tension on the waist elastic 21 fs coordinated with
the tension of the
waist portion elastic 22 to form a snug tit about the waist opening 20 while
providing a smooth
transition from the upper body portions 40 and 41 to the front and back waist
edge portions 44 and
45. However, the tensions and the LYCRA~ counts of the waist elastic 21 and
the waist portion
elastic 22 can be different.
In the front and back body portions 14 and 15, the ieg liner 38, the waist
liner 28, and /or the
topsheet layer 49 may be expanded to cover the interior of the body portions
14 and 15. In
another embodiment, the leg liner 38, the waist liner 28, andlor the topsheet
layer 49 may exclude
the center crotch portion 18 which is covered by the application of the
absorbent barrier composite
46. In the body portions 14 and 15 where the absorbent barrier composite 46
overlaps the liner 80,
the composite 46 is applied on top of any liner 80 present so as to contact
the wearer. However,
the overlapping portion of the absorbent barrier composite 46 may be
sandwiched between the
outer cover 13 and the body liner 80.
For embodiments having waist portion elastic 22, leg elastics 32, 33, 34, and
35, and crotch
etastlcs 37 and 39, the following ranges for the tensions of the elastics 22,
32, 33, 34, 35, 37, and
39 are provided in TABLE I below.
35
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TABLE I
Acceptable More Acceptable Most Acceptable
Range Range Range
Lower Upper Lower Upper Lower LimitUpper
Limit Limit Limit Limit Limit
Waist 10 grams 150 grams30 grams 100 grams45 grams 75 grams
Elastic
22
Leg 20 grams 400 grams80 grams 220 grams120 grams 180 grams
Elastics
32, 33,
34,
and 35
Crotch 20 grams 400 grams80 grams 220 grams120 grams 180 grams
Elastics
37
and 39
For embodiments having waist elastic 21, waist portion elastic 22, leg
elastics 32, 33, 34,
and 35, and crotch elastics 37 and 39, the following ranges for the tensions
of the elastics 21, 22,
32, 33, 34, 35, 37, and 39 are provided in TABLE II below.
TABLE II
Acceptable More Acceptable Most Acceptable
Range Range Range
Lower Upper Lower Upper Lower LimitUpper
Limit Limit Limit Limit Limit
Waist 30 grams 300 grams50 grams 200 grams100 grams 175 grams
Elastic
21
Waist 10 grams 150 grams20 grams 100 grams40 grams 60 grams
Elastic
22
Leg Elastics20 grams 400 grams80 grams 220 grams120 grams 180 grams
32, 33,
34,
and 35
Crotch 20 grams 400 grams80 grams 220 grams120 grams 180 grams
Elastics
37
and 39
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The tensions of the waist elastic 21, waist portion elastic 22, crotch
elastics 37 and 38, and leg
elastics 32, 33, 34, and 35 were determined as follows. Samples having the
dimensions of 10 mm
wide and 51 mm in length were tested for each of the elastics 21, 22, 32, 33,
34, and 38. The
tensions stated in TABLE i and TABLE II are given in grams per a 10 mm width.
If the size of the
sample being tested varies from a 10 mm width, the values must be normalized
to a 10 mm width.
The tensions were measured dung the first cyGe extension at 100 percent
elongation at room
temperature and humidity.
The side seams 84 and 70 may be made on the inside or outside of the underpaM
12 or
formed flat against the underpaM 12 to give a more finished look to the
underpaM 12 and to
prevent the side seams 64 and 70 from showing through clothing. Optionally,
the lateral edges 80,
82, 66 and B8 of the front and back body portions are not overlapped but are
formed flat and
extend out laterally. The side seams 64 and TO should be minimal in width
while providing
sufficient strength to be pulled up and down many times over a 24 hour wear
period without tearing
or breaking. Suitable side seams and seals are described in U.S. Patents
4,810,881 issued
September 9, 1988, to Strohbeen et at., 4,841,381 issued February 10, 1987 to
Heran et al., and
4,848,382 issued March 3, 1987 to Heran et al. which are incorporated herein
by reference.
The side seams 64 and 70, respectively, of the outer cover 13 are sealed by
means known
in the art, such as ultrasonic bonding, stitching heat/pressure bonding or
adhesive bonding. The
maximum seam strength attainable is dependent upon materials used, bond
pattern, bond width,
and process settings of dwell time, power, and pressure. Suitable side seams
typically utilize
ultrasonic bonding to achieve a seam strength such that the side seams 64 and
TO do not tear or
open during use.
The side seams 64 and TO may have an unbonded portion outboard of the bonded
area to
provide for a soft edge to each of the side seams 64 and 70. This unbonded
portion can ranged
from about 0 to about 13 mm in width, more preferably from about 1 to about 8
mm in width and
most preferably from about 2 to about 3 mm in width. Alternatively, the entire
seam width (banded
portion plus unbonded portion) may be less than about 0.8 inch (15 mm}. If the
seam is trimmed
or cut close to the outer edge of the bond area, a sharp edge is produced
along the seam edge
which can catch on clothes or be irtitating to the wearer's skin.
Having thus described the invention in full detail, it will be readily
apparent that various
changes and modifications may be made without departing from the spirit of the
invention. All
such changes and modification ana contemplated as being within the scope of
the present
invention, as defined by the following claims.
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