Note: Descriptions are shown in the official language in which they were submitted.
21 90~87
PATENT
DISPOSABLE ABSORBENT TRAINING PANT HAVING IMPROVED RECUMBENT
WASTE CONTAINMENT FEATURES
B~ckgrol~nd of the Invention
The present invention relates to disposable absorbent
training pants, and more particularly to a disposable
absorbent training pant having improved waste containment for
children in a recumbent position, such as when they are
asleep in bed.
Disposable absorbent articles have been designed and used for
various purposes. For example, some have been designed for
use as diapers for babies; as training pants for younger
children in the potty training stage, generally between the
age of 18 months to 36 months; or as incontinence products
for adults. One of the most important functions of any
disposable absorbent article is that it contain liquid and
other waste material. Failure to do so results in-leakage
and wetting of the clothes, which is undesirable to the
wearer and caregivers.
Generally, leakage will occur at the leg openings and the
waist opening. In order to prevent leakage at these
2 ! 902&7
openings, stretched elastic members have been attached at the
leg and waistopenings to provide an elastic seal, at the
wearer's legs and waist. Current absorbent articles include
various designs and constructions incorporating these elastic
members with the intent of containing liquid and waste
matter. They have not, to date, been entirely successful in
this area.
For example, if a child wearing a current training pant
urinates at a flow rate, or in a quantity, that exceeds the
absorption rate, or absorption capacity, of the training
pant, the urine can pool at the leg and waist openings, and
eventually leak through the openings. This leakage is likely
to occur at the leg openings during the daytime when the
child is upright, and at the waist opening during the night
when the child is asleep.
Waist leakage for boys, particularly when laying down, is
generally of greater concern than for girls, since boys
urinate at an area relatively nearer the walstline; whereas
girls urinate relatively closer to the crotch area.
Another reason for this waist leakage for boys is that some
current training pants may not have sufficient absorption
capacity at the front waist area, or may not absorb urine at
a rapid enough rate to prevent leakage in this area.
Attempts to overcome this front waist leakage have included
increasing the absorption capacity by adding more absorbent
21qQ~7
fluff or superabsorbent material, or both. Although this
does increase the absorption capacity at the front, leakage
still occurs when the flow rate of urine exceeds the
absorption rate of the absorbent material.
However, there is a problem with increased absorbency at the
front waist area in that it can become quite heavy from
absorbing the urine. This increased weight tends to pull the
waist of the training pant below the waistline and away from
the child's body, thereby forming a gap between the pant and
child through which urine can leak.
Finally, all of the above problems are of greater magnitude
for those older children who continue to "bed wet", i.e.,
experience nocturnal incontinence, beyond the usual potty
training age. These older children are generally three to
six years old, and their rate of flow and volume of urine is
much greater than younger children.
In view of the above, it is apparent that there still exists
a need for improving waste containment and fit at the child's
waist, particularly when the child is laying down.
Summary of the Invention
In response to the discussed difficulties and problems
encountered in the prior art, a disposable absorbent training
pant having improved recumbent waste containment features has
been discovered.
~1 90287
In one form of the present invention there is provided a
disposable absorbent training pant having a three-dimensional
pant body that defines a pant interior, a waist opening, and
a pair of leg openings. The pant body includes a front
panel, a crotch panel, a back panel, and an absorbent
structure in the pant interior. A waist peripheral region
has a waist peripheral edge generally circumscribing the
waist opening. An elastic waist barrier in the pant interior
is joined to the waist peripheral region near the waist
peripheral edge, and extends vertically downwardly from the
waist peripheral edge to form a trough.
More particularly, the invention provides a disposable
absorbent pant, comprising: a three-dimensional pant body
defining a pant interior, an interior surface, a waist
opening, and a pair of leg openings, said pant body including
a front panel, a crotch panel, a back panel, and an absorbent
structure in said pant interior, a waist peripheral region
having a waist peripheral edge generally circumscribing said
waist opening, and an elastic waist barrier in said pant
interior and being joined to said waist peripheral region near
said waist peripheral edge thereof, said elastic waist barrier
extending vertically downwardly from said waist peripheral
edge to form a trough, said elastic waist barrier having a
hydrohead value of at least about 30 centimeters or more of
water to provide sufficient resistance to liquid penetration
to allow adequate time for absorption by said absorbent
structure.
21 qO287
In another form of the present invention there is provided a
disposable absorbent training pant having a front panel, a
back panel, and a crotch panel between the front panel and
back panel. The front panel has a pair of elastic front side
sections and a front central section, and the back panel has
a pair of elastic back side sections and a back central
section. An absorbent structure is provided with an
absorbent front edge and a pair of absorbent side edges. A
pair of side seams join the elastic front side sections to
the elastic back side sections to define a pant interior, a
waist opening, and a pair of leg openings. An elastic waist
barrier includes a pair of elastic side portions, an elastic
central portion, and opposite side edges. The elastic
central portion is joined while in a stretched condition to
the front central section by a generally horizontal
continuous liquid barrier bond line, and the elastic side
portions are joined while in a generally relaxed condition to
4a
21 90287
the elastic front side sections. A pair of generally
~ vertical continuous liquid barrier bond lines extending
vertically downwardly from the generally horizontal
continuous liquid barrier bond line form a trough.
In still another form of the present invention there is
provided a disposable absorbent training pant having a three
dimensional pant body defining a pant interior, a waist
opening, and a pair of leg openings. An absorbent structure
is disposed in the pant interior. A waist peripheral region
has a waist peripheral edge generally circumscribing the
waist opening, and an elastic waist barrier is joined to the
waist peripheral region to form a trough. The elastic waist
barrier includes a gatherable layer and a mechanism for
elasticizing the gatherable layer.
Brief Description of the Drawings
The above-mentioned and other features of the present
invention and the manner of attaining them will become more
apparent, and the invention itself will be better understood
by reference to the following description of the invention,
taken in conjunction with the accompanying drawings, wherein:
Fig. l illustrates a front perspective view of one type of a
disposable absorbent training pant incorporating the
principles of the present invention;
21 ~0287
Fig. 2 illustrates a top plan, partially broken away view of
- the training pant in Fig. 1 in a partially disassembled,
stretched flat state;
Fig. 3 illustrates a cross-sectional view of Fig. 2 taken
along line 3-3 and viewed in the direction of the arrows;
Figs. 4-6 illustrate exploded side views of elastic waist
barriers according to the principles of the present
invention; and
Fig. 7 illustrates a representative light box, clamps, and
weights for use with the described TEST PROCEDURE.
Detailed Description
Referring to Fig. 1, disposable absorbent training pant 10 of
the present invention comprises a three ~; ?~ional pant body
12 comprising a front panel 14, a back panel 16, and a crotch
panel 18 interconnecting front panel 14 with back panel 16.
A pair of tearable, nonrefastenable side seams 20 joined
selected portions of front panel 14 and back panel 16 to
define a pant interior 22, a waist opening 24, and a pair of
leg openings 26. A waist peripheral region 28 of pant body
12 includes a waist peripheral edge 30 generally
circumscribing waist opening 24. Pant body 12 further
includes an interior surface 32, which may or may not be the -
surface that directly contacts the child's skin.
The use of the term "disposable" in describing absorbent
~ training pant 10 means that it is designed to be used until
soiled, either by urination, defecation, or otherwise, and
then discarded-rather than being washed and reused again. In
describing pant body 12 as "three dimensional", it is meant
that it has a waist opening 24 and a pair of leg openings 26
formed by front panel 14, back panel 16, and side seams 20.
Thus, a three dimensional garment is different from a "two
dimensional" garment, such as a baby diaper, that utilizes
refastenable adhesive tapes or mechanical fasteners, which
permit the diaper to be fastened and refastened multiple
times during use.
Training pant 10 is suitable for use for both boys and girls
in the potty training stage, which generally occurs in the
age range of about 18 months to about 36 months. However,
some boys and girls exceed this potty training range and may
continue to wet their clothes up to an age of about 6 years
old. Of particular concern are boys who are in the age range
of about 3 to about 6 years old, since the target zone of
urination for boys is generally nearer the waistline, whereas
the target zone for girls is generally nearer the crotch
area. Consequently, for boys, there is an increased
probability of leakage at the pant waist, and particularly
when the child is in a recumbent position during sleep,
either at night or during daytime naps. Most of the leakage
in a recumbent position occurs during the time the child is
asleep in a prone or side position. The term "prone" refers
to a position in which the front of the child's body faces
2~ 9~2~7
the supporting surface, such as the child's bed. The term
- "supine" refers to a position in which the child's back faces
the supporting surface. The term "side" refers to a position
in which the-child's side, either the left or the right,
faces the supporting surface. The term "recumbent" refers to
a posture or position assumed by the child when lying down,
and will include those positions referred to as prone,
supine, side, or a position somewhere between any two.
Disposable absorbent training pant 10 of the present
invention specifically addresses the earlier-described
problems of increased leakage and improper fit at the waist
area when the child is in a recumbent position. These two
problems of increased leakage and improper fit are
significantly minimized by the provision of a unique elastic
waist barrier 34. When joined to waist peripheral region 28,
the unique elastic waist barrier 34 forms a trough 36 for
cont~; n; ng urine so that it does not leak at waist opening
24, and provides the necessary time for the urine to be
absorbed. Additionally, elastic waist barrier 34 provides
improved elastic seal characteristics at the waist to prevent
it from separating or gapping away from the child's body as
the absorbent becomes heavier due to urine absorption.
Referring primarily to Fig. 2, pant body 12 includes a liquid
permeable topsheet 38, a liquid impermeable backsheet 40, and
an absorbent structure 42 suitably joined between topsheet 38
and backsheet 40.
2~ 9u2~7
Topsheet 38 is compliant, soft feeling, and nonirritating to
- the child's skin, and permits liquids to readily penetrate
through its thickness. Topsheet 38 may be manufactured from
a wide range of materials, such as porous foams, reticulated
foams, apertured plastic films, natural fibers, synthetic
fibers, or from a combination of natural and synthetic
fibers. If topsheet 38 comprises substantially hydrophobic
material, the hydrophobic material can be treated with a
surfactant or otherwise processed in order to impart a
desired level of wettability and hydrophilicity. One such
surfactant is a 0.28% Triton X-102 surfactant. A suitable
liquid permeable topsheet 38 is a nonwoven bicomponent web
having a basis weight of about 27 grams per square meter
(gsm). The nonwoven bicomponent web may be a spunbond
bicomponent web, or a bonded carded bicomponent web.
Suitable bicomponent staple fibers include a
polyethylene/polypropylene bicomponent fiber available from
CHISSO Corporation, Osaka, Japan. In this particular
bicomponent fiber, the polypropylene forms the core and the
polyethylene forms the sheath of the fiber. Other fiber
orientations are possible, such as multi-lobe, side-by-side,
end-to-end, or the like.
Backsheet 40 is impermeable to liquids and is preferably
manufactured from a thin plastic film, although other
flexible liquid impermeable materials may also be used.
Backsheet 40 prevents the exudates absorbed and contained in
absorbent structure 42 from wetting articles which contact
training pant lO, such as bed sheets and clothing. A
21 ~J 2 ~ 7
suitable liquid impermeable backsheet 40 is a l.0 mil
~ polyethylene film obtainable from Edison Plastics Company of
South Plainfield, New Jersey. Backsheet 40 can be embossed
and/or matte-finished to provide a more clothlike appearance.
Furthermore, backsheet 40 can permit vapors to escape from
absorbent structure 42, while still preventing exudates from
passing through backsheet 40. A suitable "breathable"
material that permits vapors to escape from absorbent
structure 42, while preventing liquid exudates from passing
through backsheet 40, is a material composed of a microporous
polymer film or a nonwoven fabric that has been coated or
otherwise treated to impart a desired level of liquid
impermeability. A suitable microporous film is a PMP-l film
material, which is available from Mitsui Toatsu Chemicals,
Inc., Tokyo, Japan, or an XK0-8044 polyolefin film available
from 3M Company, Minneapolis, Minnesota.
Backsheet 40 and topsheet 38 are desirably congruent, i.e.,
of the same size and shape. If desired or nec~ss~ry, either
topsheet 38 or backsheet 40 can have a different size and/or
shape from the other. Backsheet 40 is positioned on the side
of absorbent structure 42 opposite from topsheet 38, and is
preferably attached to absorbent structure 42 by any suitable
means well known in the art. For example, backsheet 40 may
be secured to absorbent structure 42 by a uniform continuous
layer of adhesive, a patterned layer of adhesive, or an array
of separate lines or spots of adhesive. Suitable adhesives
can be obtained from Findley Adhesives, Inc., Wauwatosa,
21 qG2~7
Wisconsin, and can be applied in any manner well known in the
art.
Absorbent structure 42 can be any structure which is
generally compressible, conformable, nonirritating to the
child's skin, and capable of absorbing and retaining liquids
and certain body exudates. Absorbent structure 42 can be
manufactured in a wide variety of sizes and shapes, and from
a wide variety of liquid absorbent materials commonly used in
the art. For example, absorbent structure 42 can comprise
pulp fluff, superabsorbent material, or a combination
thereof. If in combination, the pulp fluff and the
superabsorbent material can be blended together, or comprise
discrete layers of fluff and discrete layers of
superabsorbent material. Various types of wettable,
hydrophilic fibrous material include naturally occurring
organic fibers composed of intrinsically wettable material,
such as cellulosic fibers; synthetic fibers composed of
cellulose or cellulose derivatives, such as rayon fibers;
inorganic fibers composed of an inherently wettable material,
such as glass fibers; and synthetic fibers composed of a
nonwettable, thermoplastic polymer, such as polypropylene
fibers, which have been hydrophilized by appropriate means.
- The fibers may be hydrophilized, for example, by treatment
with silica, treatment with a material which has a suitable
hydrophilic moiety, or the like.
Suitable superabsorbent materials may be organic or
inorganic. Suitable inorganic superabsorbent materials
2i 9~;'87
include, by way of example, absorbent clays and silica gels.
Suitable organic superabsorbent materials include natural
materials, such as pectin and peat moss, as well as synthetic
materials, such as synthetic hydrogel polymers. Suitable
superabsorbent materials are available from various
commercial vendors, such as Dow Chemical Company, Hoechst-
Celanese Corporation, and Allied Colloids, Inc. Typically, a
superabsorbent 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.
In one embodiment, absorbent structure 42 is generally
rectangular in shape, and comprises a blend of wood pulp
fluff and superabsorbent material. One preferred type of
pulp fluff is identified with the trade designation CR1654,
available from Kimberly-Clark Corporation, Neenah, Wisconsin,
and is a bleached, highly absorbent sulfate wood pulp
cont~;ning primarily soft wood fibers. The fluff and
superabsorbent material in absorbent structure 42 are present
in a ratio Or about 9 grams to about 20 grams fluff to about
7 grams to about 14 grams superabsorbent material. The
absorbent structure 42 has a density within the range of
about 0.10 grams per cubic centimeter to about 0.35 grams per
cubic centimeter. The absorbent structure 42 may or may not
be wrapped or encompassed by a suitable tissue wrap that
maintains the integrity and/or shape of the absorbent
structure 42.
2 1 qo2~,7
For purposes of description herein, topsheet 38 and backsheet
- 40 are of the same size and shape, and as viewed in Fig. 2,
define a pant front edge 44, a pant back edge 46, and a pair
of leg cutouts-48, which form leg openings 26 in the finished
product, as illustrated by training pant 10 in Fig. 1.
A containment flap S0 is disposed on each side of absorbent
structure 42. As illustrated in Fig. 2, each containment
flap 50 includes a proximal edge 52, a distal edge 54, and a
flap elastic 56 elastically associated in each distal edge
54. Each proximal edge 52 of a containment flap 50 is
adhesively attached to topsheet 38 just slightly spaced apart
from an absorbent side edge 58. Each flap elastic 56 is
adhesively joined in a stretched condition to a respective
distal edge 54, in a manner well known in the art. The
respective ends of each containment flap 50 are coincident
with pant front edge 44 and pant back edge 46, although this
is not a necessary requirement.
Containment flaps 50 are, like topsheet 38 and backsheet 40,
made of a suitable flexible material. As used herein, the
term "flexible~ refers to materials which are compliant and
will readily conform to the general shape~and contours of the
child's body. Each flap elastic 56 can be a single or
2~ multiple ribbon or strand of suitable elastic material, which
when joined in a stretched manner to a respective containment '
flap 50, will contract a distal edge 54 sufficiently away
from topsheet 38 in order to form a channel or pocket between
a containment flap 50 and topsheet 38, thereby permitting the
21 90~S7
retention of body exudates. Containment flaps s0 can be
manufactured from a wide variety of materials such as
polypropylene, polyester, rayon, nylon, foams, plastic films,
elastic films, and the like. Various manufacturing
techniques can be used to make containment flaps 50, such
that they may be woven, nonwoven, spunbond, carded, or the
like. Containment flaps 50 may also be made of the same
material as that of which topsheet 38 is made.
Flap elastics 56 can be made of any suitable elastic
material, and one suitable such material and construction is
a plurality of strands of LYCRA~ 940 decitex that are joined
at their ends to respective distal edges 54 while at an
elongation of about 300 percent. Each individual strand is
spaced from an adjacent strand by about 3 millimeters. These
types of elastic strands can be obtained from E.I. DuPont de
Nemours Company, Wilmington, Delaware. Other suitable
elastic materials include natural rubber, synthetic rubber,
or thermoplastic elastomeric polymers. These elastic
materials may also be heat-elasticizable, and can be single
or multiple ribbons of elastic material.
Other constructions of suitable containment flaps are
described in U.S. Patent No. 4,704,116 issued November 3,
1987 to Enloe.
~s illustrated in Fig. 2, pant body 12 is in a partially
disassembled, stretched flat condition, and as previously
14
21 ~02S7
mentioned includes front panel 14, back panel 16, and crotch
panel 18. The total product, or pant, length is that length
of pant body 12 in Fig. 2 measured between pant front edge 44
and pant back edge 46 in a vertical direction. By "vertical
direction" is meant a top-to-bottom or bottom-to-top
direction with respect to Fig. 2. Similarly, the term
"horizontal direction" re~ers to a direction perpendicular to
the vertical direction. Generally speaking, each of the
panel lengths, that is front panel length 60, crotch panel
length 62, back panel length 64, will have a length
approximately 1/3 the total product length measured between
pant front edge 44 and pant back edge 46.
In Fig. 2, front panel 14 comprises a front central section
66 and a pair of elastic front side sections 68, 70 having
respective front side edges 72, 74. Similarly, back panel 16
comprises a back central section 76 and a pair of elastic
back side sections 78, 80 having respective back side edges
82, 84. During the manufacturing process, pant body 12 is
folded to substantially align front side edge 72 with back
side edge 82, and front side edge 74 to back side edge 84.
Thereafter, these aligned edges are suitably joined together,
such as by ultrasonic bonding, in order to form side seams 20
(Fig. 1). One method for aligning and bonding a folded
article is described in U.S. Patent No. 5,046,272 issued
September 10, 1991 to Vogt et al.
~1902~7
Prior to the folding and bonding to form side seams 20, a
pair of leg elastic members 86 are suitably joined to pant
body 12 at least at crotch panel 18. Each leg elastic member
86 can be any suitable construction well known in the art.
One suitable construction is that described in U.S. Patent
No. 4,940,464 issued July 10, 1990 to VanGompel et al.
Another suitable construction for a leg elastic member 86 is
a stretch bonded laminate comprising any suitable material
having elastic properties. Examples of such suitable elastic
materials include films or layers of natural rubber,
synthetic rubber, or thermoplastic elastomeric polymers.
These materials can be arranged or manufactured as panels, or
as single or multiple threads, filaments or ribbons. The
materials may also be heat-elasticizable. The elastic
materials of which flap elastics 56 are made may also be
utilized in leg elastic members 86. Each leg elastic member
86, as a stretch bonded laminate, comprises at least one
gatherable layer and one elastic layer or multiple threads of
elastic material. As used throughout this description of the
invention, the term "elastic" refers to that property of a
material or composite or laminate that causes it to recover
its original size and shape after removal of a force causing
the deformation, and is expressed as a percent. The term
"join", "joining", or variations thereof, when used in
describing the relationship between two or more elements,
means that the elements can be connected together in any
suitable manner, s~ch as by heat sealing, ultrasonic bonding,
16
2 i 9~87
thermal bonding, adhesives, stitching, or the like; these
elements can be joined directly together, or may have one or
more elements interposed between them, all of which are
connected together. Finally, the phrase "elastically
joined", or variations thereof, generally describes the
joining of an elastic member to a non-elastic member such
that the two joined members exhibit elasticity or elastic
properties. A suitable stretch bonded laminate construction
for use as a leg elastic member 86 comprises two gatherable
layers of spunbond polypropylene having a basis weight of
about 14 grams per square meter (gsm) with a layer of
meltblown elastic material having a basis weight of about 16
gsm therebetween. The layer of elastic material is
stretched, the two layers of polypropylene are then joined to
the stretched elastic layer, and upon relaxing the layers,
the polypropylene layers are gathered by the elastic layer.
Continuing to refer to Fig. 2, elastic front side section 68
and elastic front side section 70 have the same size and
shape, and are similarly constructed with the same materials.
Furthermore, elastic front side sections 68, 70 can be
separate elastic structures suitably joined to front central
section 66, such as that described in U.S. Patent No.
4,940,464 issued July lO, l990 to VanGompel, the contents of
which are incorporated by reference herein. In this
embodiment, each elastic front side section 68, 70 is a
stretch bonded laminate made of any suitable materials, such
as those identified in the aforementioned U.S. 4,940,464. In
this specific construction, elastic front side section 68 has
21 qa,~at7
-
a front edge coincident with pant front edge 44, a side edge
- coincident with front side edge 72, and an inner edge so.
Similarly, elastic front side section 70 has a front edge
coincident with pant front edge 44, a side edge coincident
with front side edge 74, and an inner edge 92.
Similarly, elastic back side section 78 is constructed to
have a back edge coincident with pant back edge 46, a side
edge coincident with back side edge 82, and an inner edge 94.
Elastic back side section 80 also is constructed to have a
back edge coincident with pant back edge 46, a side edge
coincident with back side edge 84, and an inner edge 96.
Elastic back side sections 78, 80 can also be separate
: elastic structures suitably joined to back central section
76, in a manner similar to that described above for joining
: elastic front side sections 68, 70 to front central section
66.
.
In the above description of pant body 12, the gatherable
layers of the stretch bonded laminate can be selected from
materials that are compatible as portions of either liquid
permeable topsheet 38 or liquid impermeable backsheet 40.
For example, the outermost gatherable layer can be liquid
impermeable and gatherable, while the innermost gatherable
layer can be liquid permeable and gatherable.
To this point in the description, dimensions have not been
described for the product or any components thereof.
Hereafter, desired dimensions will be provided, and these
- 21 90287
dimensions can be determined by the following described
- procedure.
- TEST PROCEDURE
EOUIPMENT AND MATERIALS
1. A suitable lightbox 156 (Fig. 7), at least 18 inches
wide x 24 inches high, such as catalog number 3670S-052
available from VWR Scientific, 600 C Corporate Court,
South Plainfield, NJ 07080. The lightbox is mounted
vertically.
2. Two clamps 158, such as Hunt/Boston brand Bulldog Clips
HUN02004, available from BT Publix Office Products,
Inc., 700 West Chicago Avenue, Chicago, IL 60610, are
mounted about 6 inches apart, near the top of the
- lightbox 156, as shown in Figure 7.
3. Two clamps 160 (the same type as described above) with
weights 162 attached, each weighing 500 + 5 grams total
weight.
4. A rigid ruler having a scale in millimeters, such as
No. C636 steel rule, available from the L. S. Starrett
Co., Athol, Mass.
5. A fine point pen or other marking device.
-
21 902~'7
TESTING PROCEDURE
l. Cut the training pant parallel to each side seam bond,
on the front panel side.
5 2. Hang the pant vertically, using the clamps, on the
lightbox, with the front end of the pant facing
downwardly and with the backsheet facing toward the
tester. In vertically hanging the pant, the pant
should be gently stretched in the horizontal direction
in order to flatten the pant sufficiently against the
lightbox. The leg elastic members must be centered
below the top clamps. Care should be taken to ensure
that the clamps are not attached to the absorbent
structure. Straighten and extend the pant by gently
running the fingers down the sides of the leg elastic
members.
3. Attach the weights to the pant waist area, making sure
they are not attached to the absorbent structure.
Again, the leg elastic members must be centered between
the bottom clamps. Then gently lower the weights, and
verify that the front end waist area is completely
stretched and the weights are hanging freely. Assure
that the pant is extended by gently running the fingers
down the sides of the leg elastic members.
4. Thereafter, length (i.e., vertical) dimensions and
width (i.e., horizontal) dimensions can be made using
the rigid ruler and fine point pen.
21 ~02~
- Referring now to Figs. 1-3, elastic waist barrier 34
generally surrounds or circumscribes waist opening 24 tFig.
1) and, for ease of manufacture, is joined to pant body 12 in
two separate elements, as illustrated in Fig. 2. In Fig. 2,
the uppermost elastic waist barrier 34 has a pair of opposed
side edges 98, 100 and the lowermost elastic waist barrier 34
has opposed side edges 102, 104. During the folding and
bonding steps of the manufacturing process for disposable
absorbent training pant 10, side edges 98, 102 and side edges
100, 104 are bonded together desirably during the formation
of and with side seams 20.
Although Fig. 2 illustrates an uppermost and lowermost
elastic waist barrier 34, the present invention contemplates
an elastic waist barrier 34 only in front panel 14 or back
panel 16. Since the present invention primarily focuses on
waste containment when the child is in the recumbent
position, the elastic waist barrier 34 in back panel 16 can
be eliminated. Since the design and construction of an
elastic waist barrier 34 in back panel 16 can be identical to
that in front panel 14, a description only of an elastic
waist barrier 34 in front panel 14 will be made.
Elastic waist barrier 34 can be designed and constructed of
any suitable elastic material known in the art. Examples of
such materials are described in U.S. Patents No. 4,940,464
and 5,246,433. Other examples of various constructions of a
suitable elastic waist barrier 34 are described in U.S.
~ 1 9~&7
Patent No. 4,652,487 issued March 24, 1987 to Morman,
In one embodiment, elastic waist barrier 34 is a stretch
bonded laminate comprising three layers of material, in which
at least the center layer has elastic properties. For
example, with reference to Fig. 4, a first gatherable layer
106 and a second gatherable layer 108 have situated
therebetween a means for elasticizing the layers 106, 108.
The means for elasticizing can be, by way of example, an
elastic layer 110 suitably joined when in a stretched
condition to gatherable layers 106, 108. Methods of joining
layers 106, 108 to a stretched elastic layer 110 include
ultrasonic bonding, thermal bonding, point bonding, adhesive
bonding, or the like. In choosing a particular means for
bonding the elastic layer 110 to the gatherable layers 106,
108, care must be taken to ensure that the bonding does not
unnecessarily inhibit the elastic characteristics of elastic
layer 110. The choice of bonding method and apparatus will
depend in major part upon the types of materials chosen, and
the desired elasticity of the stretch bonded laminate.
It is desirable that at least one of the layers is liquid
impermeable, and desirably that layer is the middle or
elastic layer 110. This permits first gatherable layer 106
and second gatherable layer 108 to be made out of appropriate
fibrous materials that give a clothlike touch and feel to the
child's body. Examples of the materials of which gatherable
layers 106, 108 are described in the aforementioned
21 ~02S7
U.S. patents. In one embodiment, first
~ gatherable layer 106 and second gatherable layer 108 are
spunbond polypropylene composed of about 2.0 to about 3.0
denier fibers, and have a basis weight of about 24 gsm and a
density of about 0.06 gm/cc. For purposes of simplicity in
manufacturing, both first and second gatherable layers 106,
108 can be made of the same material and have the same basis
weights. However, if desired, layers 106, 108 can be made of
different materials, the same material but with different
densities or basis weights, or other desired constructions.
In another embodiment, first and second gatherable layers
106, 108 can be liquid impermeable. The term "liquid
impermeable" when used in describing a laminate, such as this
one, means that liquid will not pass through the laminate,
under ordinary conditions of use, in a direction generally
perpendicular to the plane of the laminate at the point of
liquid contact. Liquid may spread or be wicked parallel to
the plane of a layer, such as a layer 106, 108, but this is
not considered to be within the meaning of "liquid
impermeable" when used with reference to a laminate.
In still another embodiment, stretched elastic strands are
adhesively joined between two layers of spunbond
polypropylene. It has been observed in some configurations
that a liquid resistant laminate is achieved by adhesively
laminating these liquid permeable, hydrophobic layers
together, without the use of any surfactant treatment. In
this embodiment, the term "liquid resistant" refers to
21 932~7
~ retarding liquid penetration through a layer, or layers, for
a sufficient period of time to allow the absorbent structure
to absorb the liquid.
A particularly desirable method of manufacturing the waist
barrier 34 includes (a) forming a meltblown elastomeric web
comprised of a suitable elastomer, (b) elongating the
meltblown elastomeric web to about 200 % beyond its relaxed
length, (c) thermally point bonding spunbond polypropylene
webs to the meltblown elastomeric web, and (d) allowing the
meltblown elastomeric web to relax and the spunbond
polypropylene webs to gather. The laminate is then slit to
the desired dimension to produce an elastic waist barrier 34
for use in an absorbent product, such as training pant 10
(Fig. 1).
In Fig. 5, there is illustrated an alternate elastic waist
barrier 112 comprising a gatherable layer 114, a flexible
liquid impermeable layer 116, and a plurality of elastic
strands 118 joined, while in a stretched condition, to both
gatherable layer 114 and liquid impermeable layer 116 by a
suitable spray adhesive 120. Gatherable layer 114 can be
made of the same or different materials as gatherable layers
106, 108, and flexible liquid impermeable layer 116 can be a
blown polyethylene film having a thickness of about 0.010
millimeter + about 0.001 millimeter, such as an XSF-367 film,
available from Consolidated Thermoplastics located in
Chippewa Falls, Wisconsin, or a 0.009 millimeter + about
0.001 millimeter stretch-thinned film such as XP 1024A,
- ~ t~'j q~287
available from Edison Plastics, located in Macalester,
Oklahoma. The spray adhesive 120 can be applied in any
suitable manner well known in the art. A particularly
desirable method of application uses a rubber based hot melt
elastic adhesive such as H2096 available from Findley
Adhesives, located in Wauwatosa, Wisconsin, and melt sprayed
at about 6 grams per square meter.
With reference now to Fig. 6, another alternate elastic waist
barrier 122 is illustrated comprising a liquid impermeable
elastic layer 124. Elastic layer 124 can be made of those
suitable elastic materials in the aforementioned and
incorporated U.S. patents, and can be either inherently
liquid impermeable or treated to be liquid impermeable by the
addition of a suitable substance, such as a surfactant.
Referring now to Fig. 2, elastic waist barrier 34 is
illustrated in its fully stretched condition, after being
suitably joined to waist peripheral region 28 of pant body
12. Generally, waist peripheral region 28 has a vertical
length between about 2 centimeters to about 6 centimeters, as
measured from pant front edge 44. As illustrated in Fig. 3,
pant front edge 44 is defined by the three edges of elastic
waist barrier 34, topsheet 38, and backsheet 40. These edges
will generally be coincident with each other as a result of
the cutting step in the manufacturing process. However, if
one of the edges of elastic waist barrier 34, topsheet 38, or
backsheet 40, as illustrated in Fig. 3, are not coincident
with the other edges, then the outermost edge, i.e., the edge
21 qO287
extending furthest to the right in Fig. 3, defines pant front
edge 44.
Elastic waist barrier 34 further includes a free edge 126,
which is spaced from topsheet 38 due to the elastic
properties of elastic waist barrier 34, as illustrated in
Fig. 3, thereby forming trough 36. The vertical, or length,
dimension of elastic waist barrier 34 (Fig. 2) is desirably
about 15 millimeters or more, and generally needs not exceed
about 6 centimeters.
Continuing to refer primarily to Fig. 2, elastic waist
barrier 34 is divided into three portions that are joined to
waist peripheral region 28. Specifically, an elastic central
portion 128 is joined to waist peripheral region 28 by a
generally horizontal, generally continuous, liquid barrier
bond line 130: and a pair of elastic side portions 132 are
suitably joined to waist peripheral region 28 by a plurality
of intermittent bonds 134. Generally, continuous bond line
130 will extend beyond, or past, absorbent side edges 58. A
pair of generally vertical bond lines 136 extend downwardly
from opposite ends of continuous bond line 130 to the free
edge 126 of elastic waist barrier 34. As illustrated in Fig.
2, vertical bond lines 136 are continuous, liquid barriers,
similar to continuous bond line 130. If desired, vertical
bond lines 136 can be intermittent, similar to intermittent
bonds 134. Vertical bond lines 136 desirably extend
downwardly from continuous bond line 130 between a respective
absorbent side edge 58 and a respective inner edge 90, 92 of
- - -
- - -
21 902~7
front elastic side sections 68, 70. An advantage of vertical
bond lines 136 being generally continuous, liquid barriers is
that they form with continuous bond line 130 a generally U-
chApe~ trough 36 for containing waste material.
Bond lines 130, 136 and intermittent bonds 134 are
constructed when pant body 12 is in the flat state with
elastic waist barrier 34 stretched or extended to the desired
elongation. The term "elongation" means the ratio of the
extension of a material to the length of the material prior
to the extension, expressed as a percent, and is represented
by the following formula:
Extended Length - Original Length x 100%.
Original Length
Bond lines 130, 136, as well as intermittent bonds 134, can
be constructed in any suitable manner well known in the art,
such as by rotary ultrasonic bonding.
In elastically joining waist barrier 34 to waist peripheral
region 28, care should to be taken in the extension of waist
barrier 34. For example, if front panel 14 is formed or
manufactured without elastic front side sections 68, 70, then
waist barrier 34 can be extended a uniform elongation
throughout the length thereof. However, if front panel 14 is
provided with elastic front side sections 68, 70, then
elastic side portions 132 of elastic waist barrier 34 may
need to be joined in a relaxed state. Elastic side portions
21 902~7
132 should have an elasticity equal to or greater than that
of elastic front side sections 68, 70, so that the joining of
elastic side portions 132 desirably will not substantially
inhibit the elastic properties of elastic front side sections
68, 70. Elastic central portion 128 can be separately
stretched or extended, and thereafter joined to waist
peripheral region 28 by continuous bond line 130 and, if
desired, vertical bond lines 136.
One of the advantages of the present invention is the choice
of method in joining elastic side portions 132 and elastic
central portion 128 to waist peripheral region 28. By
selectively varying the extensions of these portions,
different elasticities can be provided along waist peripheral
region 28. For example, elastic side portions 132 could have
an extension greater than, the same as, or less than that of
elastic central portion 128, in order to provide differential
elasticity about the waist opening 24 of training pant 10
(Fig. 1). This is particularly advantageous when segments of
waist peripheral region 28 have different basis weights, are
composed of different layers of material, or the like.
Turning now to Fig. 3, absorbent structure 42 further
includes an absorbent front edge 138, which is substantially
straight or linear, as viewed in a left-to-right direction in
Fig. 2, but which in some cases can be non-linear. In this
latter case of a non-linear front edge l38, the positional
relationship between a non-linear front edge 138 and a
straight bond line 130 (Fig. 2) is measured from that point
;~1 90287
on the non-linear front edge 138 that is the closest to bond
line 130. In some constructions, a tissue wrap encompassing
or wrapping the absorbent material of absorbent structure 42
may extend beyond the end of front edge 138. For purposes of
this part of the description, such tissue wraps are not
considered to be part of the absorbent structure 42. While
in some embodiments the absorbent front edge 138 is abrupt,
in other embodiments absorbent structure 42 may have a non-
abrupt front edge 138, such as when the absorbent structure
42 tapers in thickness towards front edge 138, is comprised
of discrete pockets of absorbent material, or the like. In
the latter case, the front edge 138 is defined as the line
where the absorbent structure 42 has a basis weight of about
60 grams per square meter. The basis weight of the absorbent
structure 42 near the front edge 138 may be determined by the
following procedure:
A S millimeter by 50 millimeter rectangle of absorbent
material is cut and removed from absorbent structure 42,
along with any tissue wrap, along a line approximately
parallel to bond line 130. If the mass of this
rectangle is 15 milligrams or greater, then it is
considered to be part of the absorbent structure 42. If
the mass is less than 15 milligrams, it is not
considered to be part of the absorbent structure 42 for
purposes of identifying front edge 138.
If absorbent front edge 138 has a curvilinear, i.e., not a
straight or linear, edge, then continuous bond line 130 can
29
Zl 90~87
be curvilinearly formed generally parallel to the curvilinear
front edge 138. In this case, the positional relationship
between absorbent front edge 138 and continuous bond line 130
can be taken at any desired location between these two
elements.
Referring to Fig. 3, continuous bond line 130 includes a bond
line inner surface 140, and a bond line outer surface 142.
As illustrated, bond line 130 has a cross section that is
generally rectangular in shape, and thus surfaces 140, 142
are generally planar. However, where the cross section of
continuous bond line 130 is of a shape different than a
generally rectangular shape, such as square, oval, flat, or
the like, positional relationships between absorbent front
edge 138 and bond line inner surface 140 are taken at that
- point or line of inner surface 140 that is closest to
absorbent front edge 138.
Although the positional relationship between absorbent front
edge 138 and continuous bond line 130 has been made in
general terms so far, this relationship is one of the unique
features of the present invention. Fig. 3 illustrates an
overall first length 144 comprising an end seal length 146, a
bond seal length 148, and a free end length 150. Overall
first length 144 is measured between absorbent front edge 138
and pant front edge 44. End seal length 146 is measured
between absorbent front edge 138 and bond line inner surface
140. Bond seal length 148 is measured between bond line
inner surface 140 and bond line outer surface 142. Free end
2 1 9~287
length 150 is measured between bond line outer surface 142
and pant front edge 44. Of these three lengths comprising
overall first length 144, the most significant are end seal
length 146 and bond seal length 148.
Another significant feature of the present invention is the
positional relationship between absorbent structure 42 and
elastic waist barrier 34. As illustrated in Figures 2 and 3,
at least the front portion of absorbent structure 42 is
encompassed or received between elastic waist barrier 34 and
liquid impermeable backsheet 40, thereby surrounding that
portion of absorbent structure 42 in a substantially liquid
impermeable pocket or trough 36. This is very important to
the present invention in improving waste containment when the
child is in the recumbent position.
These positional relationships described above are important
to the present invention, and particularly in providing
optimum performance when the child is in the recumbent
position. A particular range of lengths, as measured in a
left-to-right direction in Fig. 3, for end seal length 146 is
about 2 centimeters or less, and a more particular range is
about 1 centimeter or less. For bond seal length 148, a
particular range of lengths is between about 2 to about 8
millimeters, and a more particular range is between about 3
to about 6 millimeters. With respect to the length of
elastic waist barrier 34 between bond line inner surface 140
and free edge 126, a particular range is between about 2
21 90~7
centimeters to about 6 centimeters, and a more particular
range is between about 2 centimeters to about 3 centimeters.
Several advantages result from the above described features
of the present invention. One is that the elastic waist
barrier 34 is uniquely beneficial to boys in the potty or
toilet training stage, particularly because of the penis
frequently being pointed toward the waist of the pant during
urination, and the tendency for the waist of the pant to
slide or move down under the weight of the wet pant, thereby
causing a gap or opening between the waist of the training
pant and the body of the child. A net effect of these two
factors is a reduction in the distance between the waist of
the pant and the origin or source of the urination. The
reduction in this distance increases the probability of
leakage at the waist, and particularly so since there is less
absorbent material in this area of the pant. Elastic waist
barrier 34 mitigates this situation in several ways. The
freedom of movement of elastic waist barrier 34 enables it to
stay in contact with the body of the child, since its elastic
properties cause at least the free edge 126 (Fig. 3) to move
upwardly or away from topsheet 38 into a position against the
body of the child. This, in effect, creates a gasket or seal
that counteracts any gapping at the waist. This movement of
elastic waist barrier 34 away from topsheet 38 creates trough
36 for containing waste material. Further, by spacing
absorbent front edge 138 from continuous bond line 130 within
the prescribed ranges, absorbent structure 42 can be placed
or positioned nearer to waist opening 24, i.e., effectively
21 90~1
higher up on the body of the child. This is advantageous in
providing additional absorbent capacity near waist opening
24.
Another advantage provided by the present invention is two
separate zones of elasticity represented by a zone 152 (Fig.
3) defined between free edge 126 and bond line inner surface
140, and a zone 154 defined by free end length 150 measured
between bond line outer surface 142 and pant front edge 44.
By varying the dimension of zones 152, 154, elastic waist
barrier 34 can provide distinctly different elastic
characteristics to waist peripheral region 28 (Fig. 1) of
training pant 10. For example, if the means for elasticizing
is the elastic layer 110 of Fig. 4, different elasticities
can be provided to zones 152, 154 by selective placement of
the bond line 130 between front edge 126 and pant front edge
44.
In the embodiment in Fig. 5, different elastic
characteristics can be provided to zones 152, 154 by
selecting the individual elastic strands with different
elastic characteristics. For example, those elastic strands
in 118 in zone 152 could have greater elasticity than those
strands 118 in zone 154, or vice versa. In fact, even within
the individual zones 152, 154, the elastic characteristics of
strands 118 can be varied as desired.
Still another advantageous feature of the present invention
is the measure of the resistance of elastic waste barrier 34
2 1 902~7
to penetration by water. In this instance, elastic waist
barrier 34 can be made of a material or materials, and have a
construction capable of supporting a hydrohead of at least
about 30 centimeters or more of water. A suitable method for
determining the resistance of elastic waist barrier 34 to
liquid penetration is INDA St~ rd Test: IST 80.4 (95).
This desired hydrohead value of at least about 30 centimeters
or more of water provides sufficient resistance to liquid
penetration to allow trough 36 to contain waste material for
an adequate period of time to allow absorbent structure 42 to
absorb the waste.
As described, the present invention provides improved
containment at the front waist area of a disposable training
pant when the child is in a recumbent position, and
particularly for boys. This improvement results from elastic
waist barrier 34 providing an improved fit and seal at the
waist, due in major part to the different zones 152, 154 of
elasticity. These zones 152, 154 not only provide a snugger
fit, but also cause elastic waist barrier 34 to remain in
contact with the child's body to counteract any gapping at
the waist. Furthermore, since absorbent structure 42 does
not inhibit the elasticity of elastic waist barrier 34, the
absorbent front edge 138 can be moved closer to the pant
front edge 44, thereby resulting in increased absorbent
capacity at the front waist area.
34
2 1 90~7
While this invention has been described as having a preferred
embodiment, it will be understood that it is capable of
further modifications. This application is therefore
intended to cover any variations, equivalents, uses, or
adaptations of the invention following the general principles
thereof, and including such departures from the present
disclosure as come or may come within known or customary
practice in the art to which this invention pertains and fall
within the limits of the appended claims.
