Note: Descriptions are shown in the official language in which they were submitted.
~
K-C 14441 CA 02289243 1999-11-10
S v _
A METHOD OF MANUFACTURING AN ABSORBENT ARTICLE
Background of the Invention
s Field of the Invention
The present invention relates to absorbent articles for absorbing and
containing bodily
exudates. More particularly, the present invention relates to a method of
manufacturing
disposable absorbent articles, such as disposable diapers, training pants, and
adult
to incontinence garments, which are designed to contain bodily exudates
including low
viscosity fecal materials.
Description of the Related Art
15 Absorbent articles, such as disposable diapers, often employ an absorbent
core located
between a liquid permeable topsheet positioned adjacent the wearer's body and
a liquid
impermeable backsheet defining the exterior surface of the garment. Liquid
exudates,
such as urine, penetrate the topsheet and are absorbed by the core while the
liquid
impermeable backsheet helps to maintain a clean and dry exterior surface.
Conventional absorbent garments are also generally used to contain and absorb
solid and
semi-solid exudates such as fecal materials which may vary significantly in
viscosity.
Absorbent garments have typically included elasticized waistbands and leg
cuffs to inhibit
the leakage of both liquid and solid exudates. Conventional absorbent garments
may also
2s include secondary containment or barrier flaps at the leg or waist sections
of the article to
further inhibit leakage.
Some conventional absorbent garments have also included a void space with a
large
opening for receiving solid waste materials. Recently developed absorbent
garments
3o have also been designed to include a topsheet having apertures to provide
an enhanced
ability to contain low viscosity materials as exemplified by U.S. Patent No.
5,342,338.
K-C 14441 CA 02289243 1999-11-10
.., _
Summary of the Invention
The present invention provides a method of manufacturing a disposable
absorbent article
which includes attaching an apertured liner to the article to provide the
article with an
s enhanced ability to contain and absorb low viscosity fecal materials.
In one form thereof, the present invention provides a method of manufacturing
an
absorbent article which includes providing a backsheet layer, a liquid
permeable topsheet
layer attached to the backsheet layer and an absorbent structure disposed
between the
io topsheet layer and the backsheet layer to thereby define an article
chassis. An apertured
liner is attached to the topsheet layer in a position whereby the topsheet at
least partially
defines a front portion of the bodyside surface of the article and the
apertured liner at
least partially defines a rear portion of the bodyside surface of the article.
15 Some embodiments of the present invention involve attaching the apertured
liner in an
overlapping relation with the topsheet. The apertured liner may also be
attached to a
topsheet whereby the entirety of the apertured liner overlays the topsheet.
Further embodiments may involve placing an absorbent body between the
apertured liner
2o and the topsheet layer. The method may also include forming a laminate
which includes
both the apertured liner and the absorbent body and cutting the laminate in a
single
operation. When such a laminate is cut in a single operation, the absorbent
body will
have outer perimeter edges, i.e., perimetrical edges, which are substantially
coextensive
with the perimeterical edges of the apertured liner. This laminate segment may
then be
2 s attached to the absorbent article.
The present invention provides numerous advantages in the manufacturing
process of an
absorbent article having a bodyside surface which includes an apertured
portion in the
fecal target area of the article.
By utilizing an apertured liner which is separate from the topsheet layer, the
present
manufacturing method facilitates the use of an apertured liner which has
different physical
characteristics than the topsheet layer. This allows the topsheet layer and
apertured liner
to be conveniently and independently optimized for their different respective
functions.
This method also allows a conventional topsheet to be employed in an absorbent
article
~ E'C-C 14441 CA 02289243 1999-11-10
., r ,
which also includes an apertured portion for enhancing the ability of the
article to contain
low viscosity fecal materials.
Another advantage provided by the present invention, is that, in some
embodiments, it
provides a manufacturing method which may be easily implemented by making only
relatively minor changes to pre-existing disposable article assembling
machinery. For
example, a pre-existing diaper machine may be readily modified to cut and
place an
apertured liner on a conventional topsheet layer and thereby produce an
absorbent article
having an apertured liner and enhanced ability to contain low viscosity fecal
materials.
to
Brief Description of the Drawings
The 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
i s accompanying drawings, in which:
Fig. 1 is a top plan view of an absorbent garment manufactured in accordance
with the
present invention;
2 o Fig. 2 is a sectional view taken along line 2-2 of Fig. 1;
Fig. 3 is a perspective view of the absorbent garment of Fig. 1;
Fig. 4 is a partially cutaway top plan view of another absorbent garment made
in
2 s accordance with the present invention;
Fig. 5 is a sectional view taken along line 5-5 of Fig. 4;
Fig. 6 is a partially cutaway schematic perspective view of an apertured liner
and attached
3o absorbent body;
Fig. 7 is a schematic perspective view of a process for assembling an
apertured liner,
topsheet layer and surge layer in accordance with the present invention; and
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K-C 14441 CA 02289243 1999-11-10
Fig. 8 is a schematic perspective view of an alternative process for
assembling an
apertured liner, topsheet layer and surge layer which is in accordance with
the present
invention.
s Corresponding reference characters indicate corresponding parts throughout
the several
views. Although the drawings are intended to illustrate the present invention,
the
drawings are not necessarily to scale and certain features may be exaggerated.
The
disclosed embodiments are set forth to exemplify the invention. The disclosed
embodiments are not intended to be an exhaustive illustration of the invention
or to be
to construed as limiting the scope of the invention to a method of making the
precise forms
disclosed.
Detailed Description of the Invention
is The following detailed description will be made in the context of making a
disposable
diaper which is adapted to be worn by infants about the lower torso. It is
readily apparent,
however, that the method of the present invention would also be suitable for
making other
absorbent articles, such as incontinence garments, training pants, and other
similar
articles which are used to absorb or contain urine and fecal materials.
With reference to Figs. 1-3, an absorbent article in the form of a disposable
diaper 20 is
illustrated. The disposable diaper 20 includes a front waist section 22, a
rear waist
section 24 and an intermediate section 26 which interconnects the front and
rear waist
sections. The lateral edges of intermediate section 26 are defined by a pair
of laterally
2 s opposed side edges 28 while the edges of the front 22 and rear 24 waist
sections are
defined by a pair of longitudinally opposed end edges 30.
An apertured liner 62 and absorbent body 68 are generally disposed in the rear
portion of
the bodyside surface 21. The apertured liner 62 has an apertured layer 64
which may be
3o formed by an apertured film. The apertured liner 62 may also include a low
density
fibrous layer 66 attached to the underside of the apertured layer 64.
The apertures located in the apertured liner permit fecal materials to be
absorbed and
contained in the low density fibrous layer 66 and in the absorbent body 68
which are both
35 located below apertured layer 64. Fecal materials contained or absorbed in
low density
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4(-C 14441 CA 02289243 1999-11-10
fibrous layer 66 or absorbent body 68 will not be in direct contact with the
skin of the
wearer.
Methods of manufacturing of an absorbent article having an apertured liner are
illustrated
s in relevant part in Figs. 7 and 8 and are discussed below in terms of
manufacturing a
diaper.
With reference to Fig. 7, the apparatus utilized to manufacture a diaper 20
having an
apertured liner includes an unwind 78 for the apertured liner 62. (Apertured
liner 62 may
to comprise a laminate including both an apertured layer 64 and a low density
fibrous layer
66 or only an apetured layer 64). An unwind 76 for the absorbent layer 68 is
also
provided.
As the apertured liner 62 and absorbent layer 68 are unwound, the two
materials are
is laminated together. A glue gun 80 applies adhesive to the bottom side
(i.e., the side
opposite the bodyside surface) of the apertured liner 62 and a nip roll 82
compresses the
apertured liner 62 and absorbent layer 68 together with the adhesive material
therebetween to thereby form a laminate with the two materials. Alternative
lamination
methods, such as thermal bonding, may also be employed to form a laminate
which
2o includes both apertured liner 62 and absorbent layer 68.
Apertures may also be placed in the absorbent body 68 to provide increased
void volume
for receiving and containing fecal materials. For example, the liner 62 and
absorbent
layer 68 may be apertured in a single manufacturing operation. The forming of
apertures
zs through both liner 62 and absorbent layer 68 in a single manufacturing
operation may also
be sufficient to attach the apertured liner 62 to the absorbent layer 68
thereby eliminating
or diminishing the need for an adhesive or other means of attachment.
Apertures may also be separately formed in the absorbent layer 68 prior to
attachment of
3o the apertured liner 62 to the absorbent layer 68. When the absorbent body
68 includes
apertures, the absorbent body apertures are not required to be in complete
registry with
the apertures in apertured liner 62. The absorbent body apertures can
separately formed
and subsequently positioned in registry, partial registry, or complete non-
registry with the
apertures in the overlying liner 64. All of the apertures present in a
particular embodiment
3s may have a similar registry or the apertures in absorbent body 68 may have
different
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K-C 14441 CA 02289243 1999-11-10
registries which may be present in various percentages and in various spatial
distributions.
The topsheet material is provided on a roll and dispensed at the topsheet
unwind 84.
s Similarly, the surge material is dispensed from the surge layer unwind 86.
The apertured
liner and surge layer materials are attached to opposite sides of the topsheet
layer using
cut and place modules 88 and 90 which are well known in the art.
In the method illustrated herein, both of the cut and place modules 88 and 90
operate in a
io similar manner. The modules cut the material to be applied, i.e., either
the apertured liner
or surge material, and include at least one roller which rotates at a speed
which is greater
than the feed rate of the material. When the roller in contact with the
material to be
applied moves at a higher rotational speed than the feed rate of the material,
the roller will
create a space between a segment of the material which is severed from the
feed
1 s material due to the differential speeds and thereby allow segments of the
material to be
attached to another material in a spaced arrangement. An adhesive is applied
to either
the topsheet layer or the applied material prior to bringing the topsheet
layer and the
applied material into contact.
2 o Alternative methods of attaching segments of material to the topsheet
layer in a spaced
relationship may also be employed. Suitable alternative methods are described
in U.S.
Patent No. 5,716,478 issued on February 10, 1998 to Boothe et al., the
disclosure of
which is hereby incorporated by reference. As exemplified by this referenced
disclosure,
cut and place modules may also utilize a plurality of arcuate transfer
segments which
2s rotate about a common axis. The transfer segments define less than 360
degrees of a
cylindrical surface which allows the segments to rotate relative to each other
and thereby
permits the rotational speed of each segment to vary. In this manner, a
transfer segment
may receive a material at a first rotational speed, increase its rotational
speed to a second
rotational speed, and subsequently transfer the material in a spaced pattern
to a web of
3o material which is moving at a speed which is greater than the original
speed of the
material being attached to the web.
As evident from the configuration of diaper 20, cut and place modules 88 and
90 are
arranged to attach the surge layer and apertured liner on opposite sides of
the topsheet
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CA 02289243 1999-11-10
K-C 14441
layer with the apertured liner being attached on the body-facing surface of
the topsheet
layer.
Registry guides 92 and 94, which are well-known in the art, are utilized to
ensure that the
s surge layer and apertured liner are attached in the desired positions on the
topsheet layer.
The registry guides monitor the progession of the topsheet layer and may
either trim or
increase the length of travel of the topsheet to implement slight adjustments
in the
spacing between adjacent segments of the materials which are applied to the
topsheet
layer following the registry guides.
to
A vacuum conveyor 96 is illustrated between the cut and place module 90 used
to apply
the surge layer and the registry guide 92 which precedes the attachment of the
apertured
liner.
is An alternative manufacturing method is illustrated in Fig. 8 which is
similar to that shown
in Fig. 7. The most significant difference between the methods illustrated in
Figs. 7 and 8
is that in the method illustrated in Fig. 8, the apertured liner 62 is adhered
to the
absorbent layer 68 prior to assembly of the absorbent article.
2 o As shown in Fig. 8, the apertured linerlabsorbent body laminate can
thereby be provided
on a single roll at laminate unwind 98. By pre-laminating the apertured liner
62 and the
absorbent body 68 off-line, one of the unwinds and one set of adhesive
equipment, i.e., a
glue gun and nip roll, may be eliminated from the diaper machine and located
at a more
convenient off-line location. This off-line lamination process can facilitate
the utilization of
2 s a pre-existing diaper machine for the manufacture of a disposable
absorbent garment
having an apertured liner by reducing the amount of equipment which must be
integrated
into the pre-existing diaper machine.
Other alternative manufacturing methods may also be employed. For example,
unwind
3o roll 98 illustrated in Fig. 8 could be used to unwind only apertured liner
64 to manufacture
an absorbent article which does not include a low density fibrous layer 66 or
an absorbent
layer 68. Furthermore, the apertured liner may be attached to the topsheet
layer prior to
the attachment of the surge layer or the surge layer may be entirely omitted.
It is also
possible to form or cut an opening, or openings, in the topsheet layer prior
to the
3s attachment of the apertured liner over, or under, such openings in the
topsheet layer.
K-C 14441
CA 02289243 1999-11-10
In some such alternative methods, the topsheet 34 could include a large
opening and the
outer edges of the apertured liner 62 could be attached to the topsheet 34 on
the side
opposite the bodyside surface. Thus, the outer edges of the apertured liner 62
would
s overlap the topsheet 34 in an underlaying manner but the opening in the
topsheet 34
would still permit the apertured liner 62 to define a portion of the bodyside
surface 21.
The illustrated topsheet layer 100 having both a surge material and apertured
liner
material attached thereto in a spaced arrangement can be fed into many
different
io conventional diaper machine configurations which are well known in the art.
In the diaper machine, the topsheet layer 100 is attached to the backsheet
layer or other
portion of the diaper chassis with the surge material and apertured liner
material in proper
registry with the remainder of the diaper and with an absorbent structure
disposed
is between the backsheet layer and topsheet layer. The individual diapers are
subsequently
separated and packaged.
Figs. 1-6 illustrate absorbent articles which may be produced with the present
method. As
can be seen in Fig. 1, the absorbent article may be a disposable diaper 20.
Absorbent
z o articles which may be manufactured in accordance with the present
invention are also
described in U.S. Patent Application Serial No. 09/195,267, filed November 18,
1998,
entitled ~An Absorbent Article having an Apertured Liner" by Merrill et al.
and having
Attorney Docket No. 13,620, the disclosure of which is incorporated herein by
reference.
25 The general configuration of the illustrated diaper 20 includes front 22
and rear 24 waist
sections which are constructed to extend substantially over the wearer's front
and rear
abdominal regions, respectively, during use. The intermediate section 26
includes the
general portion of the diaper 20 which is constructed to extend through the
wearer's
crotch region between the legs. The opposed side edges 28 define leg openings
for the
3 o diaper and are generally curvilinear or contoured to closely fit the legs
of the wearer. The
opposed end edges 30 define a waist opening for the diaper 20 and are
typically straight
but may also be curvilinear.
Fig. 1 is a representative plan view of the diaper 20 in a flat, uncontracted
state with the
35 surface of the diaper which contacts the wearer, i.e., the bodyside surface
21, facing the
K-C 14441 CA 02289243 1999-11-10
viewer. Fig. 2 is a representative sectional view of the diaper 20 taken
through a rear
portion of the intermediate section 26.
The diaper 20 includes a substantially liquid impermeable backsheet 32, a
porous, liquid
s permeable topsheet 34 positioned in facing relation with the backsheet 32,
and an
absorbent structure 36, such as an absorbent pad, located between the
backsheet 32 and
the topsheet 34. In the garment illustrated in Figs. 1-3, the absorbent
structure 36
includes both a primary absorbent body 35 and a surge layer 60. The diaper 20
also
defines a lateral axis 38 and a longitudinal axis 40. The lateral and
longitudinal axes are
io also referred to herein as the lateral and longitudinal directions.
The topsheet 34 suitably presents a bodyfacing surface which is compliant,
soft feeling,
and nonirritating to the wearer's skin. Further, the topsheet 34 may be less
hydrophilic
than the absorbent structure 36, to present a relatively dry surface to the
wearer, and is
1 s sufficiently porous to be liquid permeable, permitting liquid to readily
penetrate through its
thickness. A suitable topsheet 34 may be manufactured from a wide selection of
web
materials, such as porous foams, reticulated foams, apertured plastic films,
natural fibers
(for example, wood or cotton fibers), synthetic fibers (for example, polyester
or
polypropylene fibers), or a combination of natural and synthetic fibers. The
topsheet 34,
20 or a portion thereof, may also be treated to impart a greater degree of
either
hydrophobicity or hydrophilicity to the selected material. The topsheet 34 is
suitably
employed to help isolate the wearer's skin from liquids held in the absorbent
structure 36.
In some absorbent articles the topsheet 34 may comprise a nonwoven, spunbond,
2s polypropylene fabric composed of about 2.8-3.2 denier fibers formed into a
web having a
basis weight of about 20 grams per square meter (g/m2) and a density of about
0.13 gram
per cubic centimeter (g/cc). The fabric may be surface treated with a
surfactant to
improve its hydrophilic properties in a manner which is well known in the art.
3o The backsheet 32 may suitably be composed of a material which is either
liquid
permeable or liquid impermeable. It is generally preferred that the backsheet
32 be
formed from a material which is substantially impermeable to liquids. The
backsheet 32
may optionally be composed of a micro-porous "breathable" material which
permits
vapors to escape from the absorbent body 36 while still preventing liquid
exudates from
3s passing through the backsheet 32.
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. K-C 14441 CA 02289243 1999-11-10
A typical backsheet can be manufactured from a thin plastic film or other
flexible liquid-
impermeable material such as a polyethylene film having a thickness of from
about 0.012
millimeter (0.5 mil) to about 0.051 millimeter (2.0 mils). The backsheet 32
may be given a
s more clothlike feeling by using a polyolefin film having a nonwoven web
laminated to the
outer surface thereof, such as a spunbond web of polyolefin fibers.
For example, the backsheet may be formed with a stretch-thinned polypropylene
film
having a thickness of about 0.015 millimeter (0.6 mil). The polypropylene film
may also
to have a spunbond web of polypropylene fibers thermally laminated thereto.
The fibers
forming the spunbond web may have a thickness of about 1.5 to 2.5 denier per
filament
with the nonwoven spunbond web having a basis weight of about 17 g/m2 (0.5
ounce per
square yard--osy).
i s The primary absorbent body 35 of the absorbent structure 36, may suitably
comprise a
matrix of hydrophilic fibers, such as a web of cellulosic fluff, mixed with
particles of a
high-absorbency material well known in the art and commonly referred to as
superabsorbent materials. The superabsorbent material is typically in the form
of discrete
particles and may be present in an amount ranging from about 5 to about 90
weight
2o percent based on total weight of the absorbent body.
The primary absorbent body 35 may have any of a number of shapes. For example,
the
absorbent core may be rectangular, I-shaped, or T-shaped. It is generally
preferred that
the primary absorbent body 35 be narrower in the crotch area than in the front
or rear
2 s portions of the diaper 20. The size and the absorbent capacity of the
primary absorbent
body 35 should be compatible with the size of the intended wearer and the
liquid loading
imparted by the intended use of the absorbent article.
The size and absorbent capacity of the primary absorbent body 35 may also be
adjusted
3o to account for the absorbent capacity and placement of the apertured liner
62 and
underlying absorbent body 68 which are schematically illustrated in Figure 6.
Optionally, a substantially hydrophilic tissue wrapsheet may be employed to
help maintain
the integrity of the primary absorbent body 35 which may consist of an airlaid
fibrous
35 structure. The tissue wrapsheet is typically placed about the absorbent
body over at least
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K-C 14441 CA 02289243 1999-11-10
the two major facing surfaces thereof and composed of an absorbent cellulosic
material,
such as creped wadding or a high wet-strength tissue.
Marginal portions of the diaper 20, such as marginal sections of the backsheet
32 and
s topsheet 34, may extend past the terminal edges of the absorbent structure
36. In the
illustrated diaper 20, the backsheet 32 extends outwardly beyond the terminal
marginal
edges of the absorbent body 36 to form side margins 42 and end margins 44 of
the diaper
20. The topsheet 34 is generally coextensive with the backsheet 32 but may
optionally
cover an area which is larger or smaller than the area of the backsheet 32, as
desired.
io
To provide improved fit and to help reduce leakage of body exudates from the
diaper 20,
the side margins 42 and end margins 44 of the diaper may be elasticized with
suitable
elastic members, such as leg elastic members 46 and waist elastic members 48.
is The various components of the diapers 20 are integrally assembled together
employing
various types of suitable attachment means, such as adhesive, sonic bonds,
thermal
bonds or combinations thereof. As used herein, the "attachment" of one
component to
another component is intended to encompass both direct attachment and indirect
attachment through means of an intervening component unless the description
explicitly
2 o refers to either direct or indirect attachment.
In the illustrated articles, the topsheet 34 and backsheet 32 are attached to
each other
and to the absorbent structure 36 with an adhesive, such as a hot melt,
pressure-sensitive
adhesive. The adhesive may be applied as a uniform continuous layer of
adhesive, a
2 s patterned layer of adhesive, a sprayed pattern of adhesive, or an array of
separate lines,
swirls or dots of adhesive. Similarly, other diaper components, such as the
elastic
members 46 and 48, may be assembled into the diaper 20 by employing one or
more of
the above-identified attachment means.
3o In the illustrated articles, the elastic members 46 and 48 are secured to
the diaper 20 in
an elastically contractible condition so that in a normal, under strain,
configuration the
elastic members effectively contract against the diaper 20. For example, the
elastic
members 46 and 48 may be elongated and secured to the diaper 20 while the
diaper is in
an uncontracted condition. In Figs. 1 and 2, the elastic members 46 and 48 are
illustrated
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K-C 14441 CA 02289243 1999-11-10
in their uncontracted, stretched condition for the purpose of clarity. Fig. 3
illustrates the
diaper 20 with elastic members 46 and 48 in their contracted state.
The diaper 20 also includes a pair of fasteners 50 which are employed to
secure the
s diaper 20 about the waist of a wearer. Suitable fasteners 50 include
interlocking materials
(such as hook-and-loop or mushroom-and-loop fasteners), adhesive tape
fasteners,
buttons, pins, snaps, and the like. A cooperating side panel member can be
associated
with each fastener and may be constructed to be nonelasticized, or to be
elastically
stretchable at least along the lateral direction 38 of the diaper 20.
to
The diaper 20 may also include a pair of elasticized, longitudinally extending
containment
flaps 52. The containment flaps 52 are configured to maintain an upright,
perpendicular
arrangement in at least a portion of the intermediate section 26. The
containment flaps
function as a barrier to the lateral flow of body exudates. The illustrated
containment flaps
1 s 52 include an elastic element 54 near a distal edge of the flaps and are
joined to the
bodyside surface of the diaper 20 by adhesives, ultrasonic bonding, or other
suitable
means.
The diaper 20 may also include laterally extending front and rear barrier
elements 56.
2 o The barrier elements 56 are elasticized and are attached in a position
which overlays the
longitidunal ends of containment flaps 52 as can be seen in Figs. 1 and 3. The
barrier
elements 56 are attached to the diaper 20 adjacent longitudinal edges 30 and
laterally
outward of the lateral edges of the barrier elements 56. Longitudinally inward
edges 58 of
the barrier elements 56, however, are not directly attached to diaper 20.
Attaching the
2s barrier elements 56 so that they overlay the distal edges 54 of the
containment flaps 52
helps to bias the distal edges 58 of the barrier elements 56 away from the
bodyside
surface of the diaper 20.
The absorbent structure 36 of the diaper 20 may optionally include an
additional
3o component in the form of a surge management layer 60 positioned directly
below the
topsheet 34 and above the primary absorbent body 35 of the absorbent
structure. The
surge management layer 60 is configured to efficiently hold and rapidly
distribute liquid
exudates to the primary absorbent body 35. Surge management layer 60 has a
fibrous
structure with a greater porosity and lower basis weight than the primary
absorbent body
35 35 to allow for the rapid intake and distribution of liquid exudates. Surge
management
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K-C 14441 CA 02289243 1999-11-10
layers are known in the art and are described in greater detail in U.S. Patent
No.
5,364,382 which is hereby incorporated by reference.
As discussed above, an apertured liner 62 is also attached to the diaper
chassis. In the
s illustrated articles, apertured liner 62 overlaps the topsheet 34 in an
overlaying manner
and defines the bodyside surface in the fecal target area of the diaper. The
fecal target
area of the diaper is the area which immediately surrounds the point on the
bodyside
surface which is positioned opposite the wearer's anus. The fecal target area
is generally
located in the rear portion of the bodyside surface 21 but may also extend
slightly into the
to front portion of the bodyside surface.
The illustrated liner 62 is shown in a schematic cross-sectional perspective
view in Fig. 6
and includes an apertured layer 64 and an absorbent low density fibrous layer
66. The
low density fibrous layer 66 is bonded to the underside of apertured layer 64
whereby the
is apertured layer 64 forms the bodyside surface of the apertured liner 62.
The absorbent
layer 66 is not necessary, however, and the apertured liner 62 may
alternatively consist of
only the apertured layer 64.
The apertured liner 62 and topsheet 34 are two separate component parts. In
other
2o words, apertured liner 62 and topsheet 34 are not a single integral piece
of material and
must be separately attached to the diaper, as, for example, by attaching them
together.
In the illustrated articles, the apertured layer 64 is a hydrophobic
polyethylene film. More
specifically, the illustrated apertured layer 64 consists of 95.8% (by weight)
low density
2s polyethylene, i.e., LDPE, and 4.2% Ti02. One such ~Im is available from
Edison Plastics
under the tradename XP3134A and consists of 94% Rexene (an LDPE having a 5.5
melt
index and a density of 0.923 g/cc) and 6% Ampacet (a Ti02 concentrate
consisting of 70%
Ti02 and 30% LDPE).
3o Apertures may be provided in the layer 64 with a pin roll or other suitable
means well
known in the art. The illustrated apertured layer 64 has an open area of 28%.
Thus, in a
diaper 20, the apertures in the apertured layer 64 define an open area which
is
approximately 28% of the bodyside surface portion defined by the apertured
layer 64.
Alternative amounts of open area, ranging from approximately 20% to 60%, may
also be
35 effectively employed with apertured layer 64. The opening area of the
apertures present
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K-C 14441 CA 02289243 1999-11-10
in the apertured layer 64 may range from an approximate equivalent circular
diameter of
from about 400 to 3000 microns or, alternatively, from about 400 to 1300
microns. The
apertures present in the illustrated embodiment have an opening area which is
equivalent
to the area of a circular opening with a diameter of approximately 700
microns. The pin
s roll manufacturing process used to form the illustrated apertures often
introduces some
variation in the size and shape of the individual apertures. For example,
originally circular
apertures may often become slightly oval due to subsequent drawing of the
material.
In alternative methods, the size and/or shape of the apertures may be
selectively varied.
1 o A single apertured liner could include two or more discrete groups of
differently sized or
shaped apertures. For example, the apertured layer 64 could include a certain
percentage of relatively small apertures with the remainder of the apertures
consisting of
relatively larger apertures where the smaller apertures are similar in size
and shape with
one another and the larger apertures are also similar in size and shape with
one another.
1 s Alternatively, the apertures could vary more continuously in size or
shape. The different
apertures could be segregated, homogenously placed, form a pattern, or be
randomly
placed on the apertured layer 64.
Alternative materials which may be used to form apertured layer 64 include
thermoplastic
2 o films with open areas and nonwoven fibrous materials. Foam materials,
particularly
closed cell foam materials which have a "skin" may also be effectively
employed as the
apertured layer 64. An apertured thin foam material will typically have a
"soft" feel which
is an advantageous property for a bodyside surface material.
2 s Additional alternative materials for apertured layer 64 include
thermoplastic netting which
contains highly permeable regions of defined size. Such netting is produced by
Nalle
Plastics Inc., having offices in Austin, Texas, under the tradename Naltex.
Biplanar
filtration netting produced by AET Specialty Net and Profile, having offices
in Salem,
Massachusetts may also be used.
The apertured layer 64 may also be treated to reduce adhesion and staining of
fecal
materials as, for example, by imparting a protein resistance to the material
or by
enhancing or imparting hydrophobic properties to the material. Such treatments
include
treatment with fluorocarbons, silicones, PLEURONICS (a triblock copolymer of
ethylene
3s oxide, propylene oxide, and ethylene oxide produced by BASF of Germany),
surfactants
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K-C 14441 CA 02289243 1999-11-10
and other treatments containing ethylene oxide, and other surface treatments
well known
in the art.
Fibrous materials, such as non-woven fabrics, are more likely to require the
enhancement
s of their hydrophobic properties with surface treatments than film materials
which are
naturally hydrophobic. The resistance of a fibrous material to wetting or
penetration of a
liquid depends upon a number of factors including the chemical nature,
geometry, fiber
surface roughness and capillary spacing of the material.
to Another advantage to the use of a film to form the apertured layer 64 is
that a film
presents a relatively smooth surface. The relatively smooth surface of a film
is unlikely to
trap fecal materials in localized surface irregularities. A fibrous material,
in contrast, has a
surface formed by individual fibers and, thus, has a textured surface with
many localized
peaks and valleys which can collect fecal materials. If fecal materials are
trapped in
i s localized pits or depressions on a bodyside surface, the fecal materials
are likely to
remain in contact with the skin of the wearer and remain visible. Thus, the
smooth
surface of a film can have beneficial skin health and stain reduction affects.
The surface
texture provided by a fibrous material, however, is an advantage for a
material which is
used as a "first wipe" to remove fecal materials from the skin of a wearer and
which must
20 "grip" or absorb the fecal materials to remove them from the skin.
Containing the fecal materials below the bodyside surface defined by apertured
layer 64
provides a generally cleaner and drier bodyside liner than conventional non-
apertured
hydrophilic bodyside liner materials which may absorb fecal fluids and tend to
retain fecal
2 s matter on top of the bodyside surface of the diaper.
It should be recognized that although relatively hydrophobic materials may be
used to
provide advantageous apertured liners because of the significant water content
of low
viscosity fecal materials, such fecal materials are comprised of more than
water. Although
3 o the other constituents of the fecal materials may or may not have an
affinity for the
various hydrophobic materials which may be used to form the apertured layer
64,
hydrophobic materials will not have an affinity for one primary constituent,
i.e., water,
which will be present in the fecal materials. It is also thought that the
hydraulic gradient
created by positioning a hydrophilic material adjacent a hydrophobic material
may possibly
35 have a minor influence in pulling fecal fluids through the apertures in
layer 64.
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. K-C 14441 CA 02289243 1999-11-10
The apertured layer 64 may be used by itself or include a low density fibrous
layer 66
laminated thereto or positioned thereunder. In the embodiment illustrated in
Fig. 6, a low
density fibrous layer 66 is laminated to the underside of apertured layer 64.
The
s illustrated low.density fibrous layer 66 is a through-air-bonded bicomponent
non-woven
carded web with a basis weight of about 23.7 g/mz (0.7 osy) and a density of
0.03 g/cc in
an uncompressed condition. The low density fibrous layer 66 has 100% binder
fibers
wherein the fibers have a polypropylene core and a concentric LDPE sheath with
a 50/50
core/sheath ratio. The fibers are 6 to 10 denier per filament (dpf) and are
treated with a
l0 0.5% by weight wettable finish. Such a material may be obtained from Chisso
of Japan
under the tradename ESC fiber with HR6 finish.
The low density fibrous layer 66 may also be formed with a variety of other
materials such
as fibers formed with polyester, rayon, pulp, nylon, polypropylene,
polyethylene, or
is combinations or blends thereof. Particularly advantageous materials for use
as the low
density fibrous layer 66 are resilient fibrous webs that maintain enough void
volume under
load to provide the void volume for containing the anticipated fecal insult.
The total void
volume available may differ for different garments depending upon the intended
wearer
and anticipated loading. For example, garments intended for use with adults
would have
2o a larger total void volume than garments intended for use with infants.
The illustrated low density fibrous layer 66 is bonded to the apertured layer
64 using heat
and pressure to form discrete bonded areas 65. It is also possible to use
other well
known means of laminating layers together to join layers 64 and 66 or to
attach the layers
2 s 64 and 66 to the diaper 20 without first joining the layers. The bonded
surface area
comprises between 8-12% of the total surface area of the apertured liner 62 in
the
illustrated embodiment but the bonded surface area is not limited to this
range. It is also
possible for bonds 65 to be configured to convey information or to form a
decorative
pattern.
The polyethylene material forming the illustrated apertured layer 64 is
hydrophobic and
thus does not absorb the fecal fluid or experience the staining associated
with such
absorption. The apertures in the layer 64 allow the passage of fecal materials
therethrough while the hydrophilic qualities of the low density fibrous layer
66 allows this
layer to absorb fecal fluid and the low density of layer 66 leaves suft'icient
void space for
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K-C 14441 CA 02289243 1999-11-10
receiving significant quantities of fecal materials. Resilient fibrous
materials can be
advantageously used to form the layer 66 underlying the apertured layer 64.
A more substantial absorbent body 68 may also be positioned between the
apertured liner
s 62 and the topsheet 34 to provide an increased capacity for absorbing and
retaining fecal
materials. The absorbent body 68 is completely overlain by the apertured liner
62.
If no topsheet 34 is present below the apertured liner 62, the absorbent body
68, if
present, is positioned between the apertured liner 62 and the absorbent
structure 36. In
to alternative configurations where no absorbent body 68 is used, the
apertured liner 62
(including only an apertured layer 64 or both an apertured layer 64 and a low
density
fibrous layer 66) may be positioned directly over the absorbent structure 36.
In the diaper
20 illustrated in Figs. 1-3 and 6, the absorbent body 68 is adhered to the
underside of
apertured liner 62.
In the illustrated articles, absorbent body 68 is a non-compressively dried
cellulosic web.
More specifically, the illustrated absorbent body 68 is an uncreped through-
air-dried,
bleached chemi-thermo-mechanical-pulp with a basis weight of approximately 40-
45 g/m2
and a density of approximately 0.3 g/cc. The absorbent body 68 has a three-
dimensional
2o surface with an overall surface depth of approximately 0.10 millimeter or
greater.
The web which is used to form absorbent body 68 may also include a wet
strength agent
and at least 10 dry weight percent high yield pulp fibers. Virgin high yield
pulp fibers and
virgin high yield softwood pulp fibers may be advantageously employed to form
such a
2s web. "High yield pulp fibers° are papermaking fibers produced by
pulping processes
which provide a yield of approximately 65 percent or greater. Such pulping
processes
include bleached chemi-thermo-mechanical pulp, thermo-mechanical pulp, thermo-
mechanical chemical pulp, high yield sulfite pulps and high yield kraft pulps.
These
processes leave the resulting fibers with high levels of lignin. High yield
fibers are well
3o known for their stiffness (in both their wet and dry states) relative to
typical chemically
pulped fibers. The lignin resists the softening effect of water and helps the
resulting web
to maintain its stiffness and shape after wetting.
The basis weight of the webs can be approximately 10 gsm or greater and, more
35 specifically, may range from approximately 20 to 80 gsm, from approximately
30 to 60
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K-C 14441 CA 02289243 1999-11-10
gsm, or from approximately 30 to 50 gsm. In the illustrated embodiment, the
basis weight
of absorbent body 68 is approximately 44 gsm. The fiber composition of the web
can
have from about 10 to 100 percent wood pulp fibers and, more specifically, may
contain
about 70 percent to 90 percent wood pulp fibers or greater. Additionally, it
is
s advantageous that softwood fibers comprise about 70 to 90 percent or greater
of the fiber
composition.
Three main factors involved in the production of cellulosic webs having the
desired
properties for absorbent body 68 are 1 ) a high bulk (low density) three
dimensional
to structure obtained without significant compression during drying and
advantageously
obtained without creping; 2) high yield pulp fibers, advantageously comprising
at least
10% of the web fibers; and 3) the use of one or more wet strength resins or
agents such
that the wet to dry geometric mean tensile strength ratio is about 0.1 or
greater. Wet
strength agents are used to make the bonds between the fibers resistant to
disruption in
1 s the wet state. Such wet strength agents are well known in the art and are
commercially
available from a wide variety of sources. Such agents include polyamide-
polyamine-
epichlorohydrin (PAE) type resins, polyamide-epichlorohydrin resins,
aminoplast resins
obtained by reaction of formaldehyde with melamine or urea. U.S. Serial No.
08/912,906
entitled Wet-Resilient Webs and Disposable Articles Made Therewith, filed
August 15,
20 1997 in the name of Chen et al., and having an attorney docket number of
11,700.3,
describes suitable wet strength agents and a method of producing cellulosic
webs suitable
for use as absorbent body 68 in greater detail and is hereby incorporated by
reference.
Cellulosic webs made in accordance with the three factors described above will
generally
2s have both low density and high wet resiliency properties, showing great
resistance to wet
collapse. Such webs also have favorable absorbency characteristics, such as
high intake
rates, high in-plane permeability, high absorption capacity and rapid in-plane
distribution
of liquids.
3o Other absorbent materials, or combinations of materials, may also be used
to form
absorbent body 68. Examples of such alternative materials include nonwoven
webs
having approximately 70% oriented rayon fibers as well as the absorbent
materials
previously described as being suitable for absorbent structure 36 or low
density layer 66.
These alternative materials include superabsorbent materials which can be used
as either
3s a substitute or supplement for the absorbent capacity of the absorbent body
68.
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K-C 14441 CA 02289243 1999-11-10
Additional features, such as flaps and barriers (not illustrated), may be used
to separate
the urine and fecal insult areas on the diaper. The use of such features can
serve to
minimize the possibility of the absorbent body 68 becoming pre-saturated with
urine and
prevent the movement of fecal materials into an area where the bodyside
surface is
defined by the topsheet layer 34 instead of the apertured liner 62.
As discussed above, the absorbent body 68 and apertured liner 62 may be
adhesively, or
otherwise, secured together prior to attaching the absorbent body 68 and
apertured liner
l0 62 to the diaper chassis. The absorbent body 68 may have an outer perimeter
which is
substantially coextensive with the apertured liner 62 or the outer edges of
apertured liner
62 may extend substantially beyond the perimeter of the absorbent body 68. The
use of
an absorbent body 68 and an apertured liner 62 having substantially
coextensive outer
perimeters, however, allows the absorbent body 68 and apertured liner 62 to be
cut
together in a single cutting operation from a laminate previously formed by
attaching the
absorbent body 68 to the apertured liner 62. The absorbent body 68/apertured
liner 62
laminate may then be attached to the disposable garment chassis.
The apertured liner 62 is positioned on the bodyside surface 21 of the diaper
20 to receive
2o fecal insults. Thus, the apertured liner 62 is positioned to define at
least a portion of the
rear portion of bodyside surface 21, i.e., that portion of bodyside surface 21
disposed
rearwardly of lateral axis 38. Lateral axis 38 is positioned at the midpoint
of the leg
openings defined by laterally opposed side edges 28 and divides the bodyside
surface 21
into a front portion and a rear portion.
The outer perimeter of apertured liner 62 is defined by front edge 70, two
laterally
opposed side edges 72 and a rear edge 74. The apertured liner 62 illustrated
in Figs. 1-3
is configured to have a front edge 70 which is positioned near the
longitudinal midpoint of
the intermediate section corresponding to axis 38. More specifically, the
front edge 70
3o illustrated in Figs. 1-3 is disposed approximately one inch (2.54 cm)
forward of the lateral
axis 38.
The apertured liner 62 extends rearwardly from its front edge 70 to its rear
edge 74. The
rear edge 74 may be advantageously disposed approximately 0.5 inches (2.3 cm)
forward
of the rear diaper longitudinal end edge 30. This positioning of the rear edge
74 allows
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. K-C 14441 CA 02289243 1999-11-10
the rear barrier element 56 to conceal the rear edge 74. The rear edge 74 may
also be
alternatively positioned. For example, the rear edge 74 of the apertured liner
62 may
coincide with the rear edge 30 of the diaper 20.
The side edges 72 of the apertured liner 62 can be advantageously disposed
laterally
inward of the flaps 52. The flaps 52 thereby generally conceal the side edges
72 from
view prior to placement of diaper 20 on a wearer.
The apertured liner 62 can be attached to the topsheet 34 whereby the topsheet
34
to underlays the entirety of the apertured liner 62, underlays only a portion
of the apertured
liner 62 or does not underlay any portion of the apertured liner 62. In the
illustrated diaper
20, the entirety of the apertured liner 62 overlays the topsheet layer 34, in
other words,
there is no opening in the topsheet layer 34 below the apertured liner 62 in
the illustrated
embodiments.
Topsheet layers 34 which do not include an opening under the apertured liner
62 can be
used to form the entirety of the bodyside surface if an apertured liner 62 is
not attached to
overlay the topsheet layer 34. In other words, the present invention may
involve attaching
an apertured liner 62 to overlay a portion of a topsheet layer 34 of a
conventionally
2 o configured absorbent article. This allows the apertured liner 62 to be
easily integrated
into, or selectively attached to, a diaper having an otherwise functionally
complete
chassis. This can allow a single manufacturing line to efficiently and
selectively produce
absorbent articles with and without an absorbent apertured liner 62 by
selectively
attaching or not-attaching an apertured liner 62 to the otherwise similar
absorbent articles.
It is thought that the apertures in the apertured liner allow a greater
quantity of fecal
materials and larger sized fecal particulates to pass through the apertured
liner than
through a conventional spunbond bodyside liner. For absorbent structures 36
which
include small loose particulates, such as superabsorbent materials, the
openings, or
3o apertures, extending through the apertured liner also increase the
potential for outward
migration of such loose particulates to the bodyside surface 21 of the
article.
Not all absorbent structures 36 will include loose particulates capable of
migrating through
the apertures in liner 64. However, an intervening layer of material can be
used with
3s absorbent structures 36 containing such loose particulates. Placing an
intervening layer
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_._ _ _. _- _ _ _r. _____._ _
- K-C 14441 CA 02289243 1999-11-10
of material, such as topsheet 34, between the apertured layer 64 of liner 62
and the
absorbent structure 36 helps to prevent the particles forming absorbent
structure 36 from
migrating through the apertures in layer 64 to the bodyside surface of the
absorbent
article. This screen-like function can alternatively be performed partially or
entirely by the
s low density fibrous layer 66 or the absorbent body 68. Tissue wrap may also
be utilized
as an intervening layer between the apertured layer 64 and the absorbent
structure 36 to
inhibit the outward migration of absorbent structure particulates.
The intervening layer advantageously has smaller apertures extending
therethrough than
to the apertures extending through the apertured layer 64 to inhibit the
outward migration of
particulates, such as superabsorbent material particulates. The intervening
layer may
also inhibit the outward migration of particulates even if it has openings as
large or larger
than the apertures in layer 64, provided the intervening layer has a
sufficient thickness or
other properties, such as an affinity for the absorbent material particulates,
which inhibit
is the outward migration of such particulates.
While this invention has been described in detail, it will be readily apparent
to a person of
ordinary skill in the art that various changes and modifications can be made
without
departing from the spirit and general principles of the invention. All of such
changes and
2o modifications are contemplated as being within the scope of the present
invention as
defined by the subjoined claims. Furthermore, this application is intended to
cover such
departures from the present disclosure as come within known or customary
practice in the
art to which this invention pertains.
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