Note: Descriptions are shown in the official language in which they were submitted.
R'O 96f06591 PCTIUS95109244
THIN ABSORBENT ARTICLE HAVING WICKING
AND CRUSH RESISTANT PROPERTIES
FIELD OF THE INVENTION
This invention relates to an absorbent article for absorbing
body fluid, especially menses and blood. More specifically, this
invention relates to a thin sanitary napkin, having a caliper less
than about 5 millimeters and having an absorbent care constructed of
at least three absorbent members, each having a pre-determined
wicking capacity along the x and y-directions.
BACKGROUND OF THE INVENTION
An absorbent article refers to products such as diapers,
sanitary napkins, training pants, incontinent garments,
overnight
pads, panty liners, under arm shields and the like, which
are used to
absorb body fluids, such as urine, menses, blood, perspiration
and
other excrements discharged by the body. Sanitary napkins,
also
referred to as catamenial pads, feminine pads, overnight
pads, panty
liners and panty shields are designed to be worn by a female
to
absorb menses and other body fluids discharged before,
during and
after a menstrual period. Sanitary napkins are external
devices
which are designed to be aligned approximate the pudendum
region of a
human body and are generally held in position by being
adhesively or
mechanically attached to an undergarment. Sanitary napkins
also
differ from panty liners and panty shields in several notable
ways.
Sanitary napkins are generally larger in size and have
a more defined
3-dimensional configuration, are thicker in caliper and
are bulkier
in appearance than panty liners or panty shields.
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219?~94 ' .
Since sanitary napkins are normally used during major discharge
portions of a menstrual period, they are constructed to absorb a
greater quantity of body'f~uid and are designed so they can be worn
for a longer period of time than a panty liner or a panty shield.
Appropriately, sanitary napkins are constructed to handle medium to ,
heavy flows and commonly have a total absorbent capacity in a range
of about 20 to 50 grams of fluid.
Today's sociological changes have enabled women to become more
active in sports and other types of physical activity. These changes
have been complimented by a change in attire and have given women the
option of wearing close body fitting clothing. Current sanitary
napkins have a caliper of greater than 6 millimeters (mm) and can
present a bulge adjacent to the pudendum when worn inside tight
fitting shorts or pants. The overall size and configuration of the
sanitary napkin can also restrict leg movement or cause discomfort
when a woman participates in physical or sporting events. In view of
this, there is a real need to develop a thin sanitary napkin which is
less than about 5 mm in caliper is resilient and yet able to absorb
as much body fluids as current available products.
In developing a thin sanitary napkin of less than about 5 mm in
caliper, it has been realized that such products have a tendency to
twist and bunch when worn. The squeezing of the sanitary napkin
between the thighs and resulting deformation as a woman moves about
causes the upper surface of the napkin to acquire curved or convex
shape. This twisting and bunching is referred to as "roping" because
the cylindrical profile can be imparted to the sanitary napkin. This
roping effect is detrimental because the napkin is unable to absorb
fluid that contacts its upper surface. The fluid discharged from the
vagina has a tendency to run off the roped napkin before it can be
absorbed. Therefore, the fluid leaks onto the undergarment. This
run-off becomes significant during periods of heavy flow. It is
therefore, desirable to construct an absorbent article which has the
capacity to rapidly wick body fluids in the x-y plane to a large
portion of the absorbent so as to prevent premature side leakage.
It is also desirable to construct an absorbent article having a
resistance to roping and bunching of the napkin during use.
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SUMMARY OF THE INVENTION
Briefly, this invention relates to an absorbent article
having a caliper of less than about 5 mm. The absorbent
article has a liquid-permeable cover, a liquid-impermeable
baffle and an absorbent core sandwiched therebetween. The
absorbent core is constructed of at least three absorbent
members which are vertically arranged with the first
absorbent member positioned adjacent to the cover and the
third absorbent member adjacent to the baffle. Each
absorbent member has an increasing fluid wicking capacity
along the x and y-axes such that the wicking capacity of the
first absorbent member is less than the wicking capacity of
the second member, and the wicking capacity of the third
absorbent member is greater than the wicking capacity of the
second absorbent member. The different wicking capacities of
the three absorbent members promotes a systematic
distribution of body fluid away from the bodyside cover and
down into the absorbent allowing a greater utilization of
the absorbent core.
According to one aspect of the present invention there
is provided an absorbent article comprising a liquid-
permeable cover, a liquid-impermeable baffle and an ,
absorbent core therebetween, said absorbent core having at
least three absorbent members vertically arranged wherein
said cover and said baffle are positioned adjacent to said
first and third absorbent members respectively, each of said
absorbent members has a fluid wicking capacity for 3
milliliters of dyed distilled water along an x-axis and y-
axis, said second absorbent member having a wicking capacity
along said x and y-axes greater than said first absorbent
member, and said third absorbent member having a wicking
capacity along said x and y-axes greater than said second
absorbent member, said absorbent article having a wet
resiliency greater than about 250 grams and having a caliper
of less than about 5 millimeters.
According to another aspect of the present invention
there is provided an absorbent article comprising a liquid-
permeable cover, a liquid impermeable baffle and an
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absorbent core therebetween, said absorbent core comprising
at least four absorbent members vertically arranged wherein
said cover and said baffle are positioned adjacent to said
first and third absorbent members respectively, and said
fourth absorbent member positioned adjacent to said second
absorbent member wherein each of said absorbent members have
a fluid wicking capacity for 3 milliliters of dyed distilled
water along an x-axis and y-axis, said second absorbent
member having a wicking capacity in said x and y-axes
greater than said first absorbent member and said fourth
absorbent member having a wicking capacity in said x-axis
and y-axis less than said third absorbent member but greater
than said second absorbent member, said absorbent article
having a crush resistance greater than about 250 grams and a
caliper of less than about 5 millimeters.
According to another aspect of the present invention
there is provided an absorbent article comprising a liquid-
permeable cover a liquid-impermeable baffle and an absorbent
core therebetween, said absorbent core comprising at least
four absorbent members vertically arranged wherein said
cover and said baffle are positioned adjacent to said first
and third absorbent members respectively and said fourth
absorbent member is a non-wet stable material positioned
adjacent to said second absorbent member wherein each of
said absorbent members have a fluid wicking capacity for 3
milliliters of dyed distilled water along an x-axis and y-
axis, said second absorbent member having a wicking capacity
along said x and y-axes greater than said first absorbent
member and said fourth absorbent member having a wicking
capacity in said x-axis and y-axis less than said third
absorbent member but greater than said second absorbent
member, said first absorbent member including bicomponent
fibers made from polypropylene and polyethylene in a side-
by-side configuration, said absorbent article having a crush
resistance greater than about 250 grams and a caliper of
less than about 5 millimeters.
The invention seeks to provide an absorbent article for
absorbing body fluids, especially menses and blood. A more
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specific object of this invention is to provide a thin
sanitary napkin having at least three absorbent members with
increasing wicking capacities.
The invention also seeks to provide a thin sanitary
napkin which will resist twisting and bunching during use.
Other objects and advantages of the present invention
will become more apparent to those skilled in the art in
view of the following description and accompanying drawings
wherein like parts are given the same reference numeral,
similar or analogous parts are designated with a prime
symbol.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a partial cutaway perspective view of a
sanitary napkin showing an absorbent core having at least
three absorbent members.
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WO 96106591 PCT/US95109244
Fig. 2 is a partial cutaway perspective view of a sanitary
napkin showing an absorbent core having four absorbent members with
the second absorbent member C-folded about an E-folded fourth
absorbent member.
Fig. 3 is a partial cutaway perspective view of a sanitary ,
napkin showing four absorbent members wherein the second absorbent
member is C-folded about a planar fourth absorbent member.
r
Fig. 4 is a perspective view of the apparatus used in
determining crush resistance in accordance with this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Fig. 1, an absorbent article 10 is shown which is
capable of absorbing body fluid. The absorbent article can be a
diaper, training pant, sanitary napkin, a panty liner, an overnight
pad, an incontinent garment, an under arm shield or any other known
disposable absorbent product capable of absorbing urine, menses,
blood, perspiration, excrements or other bodily fluids discharged by
a human. For purposes of discussion and illustration only, the
absorbent article 10 will be described in terms of a sanitary napkin.
It will be understood by those skilled in the art that the invention
disclosed herein can be used for any number of disposable absorbent
products.
The sanitary napkin 10 includes a liquid-permeable cover 12, a
liquid-impermeable baffle 14 and an absorbent core 16 enclosed
therebetween. The focus of this invention is directed to-the liquid
absorbing core 16 and the absorbent and crush resistant properties
imparted to the sanitary napkin 10. The absorbent core 16 is
constructed of at least three absorbent members: a first absorbent
member 18, a second absorbent member 20 and a third absorbent
member 22, which are arranged in a vertically superposed position.
Using the cover 12 as a point of reference, the absorbent members 18,
ZO and 22 are arranged so that the first absorbent member 18 is
positioned adjacent to the cover 12, the second absorbent member 20
is positioned below the first absorbent member 18 and the third
absorbent member 22 is positioned adjacent to the baffle 14. The
absorbent members 18, 20 and 22 can be arranged within the absorbent
core 16 so that the wicking capacity for each successive absorbent
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member from the cover 12 to the baffle 14 increases relative to the
preceding absorbent member. For example, the second absorbent
member 20 has a wicking capacity greater than the first absorbent
member 18 and the third absorbent member 22 has a wicking capacity
greater than the first or second absorbent members, 18 or 20,
respectively. This construction allows a greater utilization of the
absorbent members 18, 20 and 22 and also the absorbent core 16.
The sanitary napkin 10 is about 150 mm to about 320 mm long, and
about 60 mm to about 120 rt~n wide and has a race track shape with
rounded ends but one would undei~stand that the shape of the sanitary
napkin is not a limiting factor. The sanitary napkin 10 has a
thickness or caliper of less than about 5 mm, and preferably less
than about 4 mm.
Looking at some of the elements of the sanitary napkin 10 more
specifically, the cover 12 is designed to contact the body of the
user and should be liquid-permeable. The cover 12 can be constructed
of a woven or nonwoven material, from synthetic or natural materials
and should be easily penetrated by body fluid. Suitable materials
include bonded carded webs of polyester, polypropylene, polyethylene,
nylon or other heat-bondable fibers. Other polyolefins, such as
copolymers of polypropylene and polyethylene, linear low-density
polyethylene, finely perforated film webs and net material also work
well. A preferred cover material is SULTEX PF10 available from
Pantex S.R.L, located in Agliana Pistoia, Italy. The cover 12 can
also be constructed of a thermoplastic film which contains apertures
and is flanked on both sides by a nonwoven material. This particular
embodiment contains a soft feel against a user's thigh while allowing
body fluid to rapidly pass therethrough.
In order to facilitate movement of body fluid down in the
sanitary napkin 10, it is possible to form a plurality of apertures
(not shown) in the cover 12. The apertures can be randomly or
uniformly arranged throughout the cover 12, or they can be located
only in the narrow longitudinal band or strip arranged along the
longitudinal axis X--X of the sanitary napkin 10. The apertures
permit rapid penetration of body fluid down into the absorbent
core 16. The size, shape, diameter any number of apertures can be
varied to suit one's particular needs.
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WO 96106591 PC1'IUS95109244
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The baffle 14 is generally liquid-impermeable and is designed to
face the inner surface, i.e. the crotch portion of an undergarment
(not shown). The baffle 14 can be designed to permit a passage of
air or vapor out of the absorbent article 10 while blocking the
passage of liquids. The baffle 14 can be made from any material ,
having the above-identified properties. A good material is
microembossed, polymeric film, such as polyethylene or polypropylene.
A preferred material is a polyethylene film having a thickness in the
range of about 0.2 mils to about 5.0 mils and preferably is about 0.5
to about 3.0 mils. The cover 12 and baffle 14 can be coextensive in
a face-to-face contact around the periphery of the absorbent core 16.
The cover 12 and baffle 14 can be sealed together about their
peripheries by use of an adhesive, by heat sealing ultrasonics or any
other process known to those in the art.
The absorbent core 16 consists of at least three separate and
distinct absorbent members 18, 20 and 22, each having an increasing
wicking capacity along the x and y-axes.
In discussing suitable structures of the absorbent core 16, the
components are described as though lying on a flat surface with the
baffle 14 underneath the absorbent core 16 and the cover 12 on top.
Accordingly, the absorbent core 16 can be described with reference to
it's x, y and z-axis described herein. The x-axis is along the
length of the sanitary napkin 10, the y-axis is transverse to the
x-axis i.e. along the width of the sanitary napkin 10 and the z-axis
is perpendicular to the x-y plane, along the depth or thickness of
the sanitary napkin 10.
The first absorbent member 18 can have a shape unitary to the
shape of the sanitary napkin 10. Preferably, the first absorbent
member 18 has a rectangular shape, with a length equal to or less
than the overall length of the sanitary napkin 10, and a width less
than the width of the sanitary napkin 10. A length of between about
152 mm to about 304 mm and a width of between about 12 mm to about 40
mm works well. Preferably, the first absorbent member 18 has a
length approximately equal to the length of the sanitary napkin 10
and a width of between about 25.4 mm to about 38.1 mm and most
preferably about 34 mm.
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The first absorbent member 18 should be made of a material that
is capable of rapidly transferring, in the z-direction, body fluid
which is delivered to the cover 12. Since the first absorbent
member 18 is of a dimension narrower than the sanitary napkin 10, the
sides of the first absorbent member 18 are spaced away from the
longitudinal sides of the sanitary napkin 10 and the body fluid is
restricted to the area within the periphery of the first absorbent
member 18, before it passes down and is absorbed into the second
absorbent member 20. This design enables the body fluid to be-
combined in the central area of the sanitary napkin 10 and to be
wicked downward so that a greater quantity of the second absorbent
member 20 can be utilized.
A suitable material for use as a first absorbent member 18
having high wicking capacity in the z-direction, is a material
available from Kimberly-Clark Corporation, in Neenah, Wisconsin,
known as PRISM.* A description of PRISM is taught in U.S. Patent
No. 5,336,552 issued to Strack et al. and assigned to the present
assignee.
PRISM is generally the nonwoven fabric and comprises
extruded multicomponent polymeric strands including first and second
polymeric components arranged in substantially distinctive zones
across the cross-section of the multicomponent strands and extending
continuously along the length of the multicomponent strands.
Preferably, the strands are continuous filaments which may be formed
by spunbonding techniques. The second component of the strands
constitutes at least a portion of the peripheral surface of the
multicomponent strands continuously along the length of the
multicomponent strands and includes a blend of a polyolefin and an
ethylene alkyl acrylate copolymer. Bonds between the multicomponent
strands may be formed by the application of heat.
More specifically, the first polymeric component of the -
multicomponent strands is present in an amount of from about 20 to
about 80 percent by weight of the strands and the second polymeric
component is present in an amount from about 80 to about 20 percent
by weight of the strands. Preferably, the first polymeric component
of the multicomponent strands is present in an amount of from about
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W096!06591 ~ PCTIUS95/09244
40 to about 60 percent by weight of the strands and the second
polymeric component is present in an amount from about 60 to about 40
percent by weight of the strands.
The term "strand" as used herein refers to an elongated
extrudate formed by passing a polymer through a forming orifice such ,
a die. Strands include fibers, which are discontinuous strands
having a definite length, and filaments, which are continuous strands
of material. The nonwoven fabric of the present invention may be
formed from staple multicomponent fibers. Such staple fibers may be
carded and bonded to form the nonwoven fabric. Preferably, however,
the nonwoven fabric of the present invention is made with continuous
spunbond multicomponent filaments which are extruded, drawn and laid
on a traveling forming surface.
The types of nonwoven materials that may be employed include
powder-bonded-carded webs, infrared bonded carded webs, and through-
air-bonded-carded webs. The infrared and through-air bonded carded
webs can optionally include a mixture of different fibers, and the
fiber lengths within a selected fabric web may be within the range of
about 1.0 to 3.0 inch and an average bulk density of about 0.02 g/cc
to about 0.06 g/cc.
The first absorbent member 18 may be a nonwoven fibrous web
which includes about 75 percent polyester fibers of at least 6
denier, such as PET (polyethylene terephthalate) fibers available
from Hoechst Celanese. The polyester fibers have a length ranging
from about 1.5 to 2.0 inches in length. The remaining 25 percent of
the fibrous web can be composed of bicomponent binder fibers of not
more than 3 denier, and preferably about 1.5 denier. The bicomponent
fiber length ranges from about 1.5 to 2 inches. Suitable bicomponent
fibers are wettable, polyethylene/polypropylene bicomponent fiber,
available from Chisso, a business having offices located in Osaka,
Japan. The bicomponent fiber can be a composite, sheath-core type
with the polypropylene forming the core and polyethylene forming the
sheath of the composite fiber. The polyester fibers and bicomponent
fibers are generally homogeneously blended together and are not in a
layered configuration. The fibers can be formed into a carded web
which is thermally bonded, such as by through-air bonding or infrared
bonding.
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WO 96106591 PCTIUS95/09244
The second absorbent member 20 is positioned vertically
below
the first absorbent member 18 and has a higher wicking capacity
along
the x and y-axes than the first absorbent member 18. Preferably,
the
second absorbent member 20 has a wicking capacity at least
three time
greater than the first absorbent member 18. The second absorbent
member 20 can have a length of about 152 mm to about 304
mm and
preferably is equal to the length of the sanitary napkin
10. The
second absorbent member 20 can be equal in width to the
first
absorbent member 18, but preferably will be wider. The width
of the
second absorbent member 20 can be from between about 50.8
mm to about
76.2 mm, and most preferably about 63.5 mm.
The second absorbent member 20 can be a hydrophilic material
formed from various types of natural or synthetic fibers
including
cellulose fibers, surfactant treated meltblown fibers, wood
pulp
fibers, regenerated cellulose, cotton fibers or a blend
of other
fibers. Preferably, the second absorbent member is a material
described in U.S. Patent No. 4,100,324, and is generally
known as
coform. Coform is available from the Kimberly-Clark Corporation
located in Neenah, Wisconsin and is generally a nonwoven
material
having a fabric-like finish and is made up of an airform
matrix of
thermoplastic polymetric fibers and a multiplicity of individualized
wood pulp fibers. The thermoplastic fiber polymers generally
have an
average diameter of less than 10 microns with the individualized
wood
pulp fibers dispersed throughout the matrix and serving
to space
these microfibers from each other. The material is formed
by
initially utilizing the primary air stream with the meltblown
microfibers and the secondary air stream containing wood
pulp fibers
and merging the two under turbulent conditions to form an
integrated
air stream along a forming surface. The fiber-like appearance
of
this material provides a visual appealing absorbent. Also
inherent
in the coform material is increased resiliency compared
to
conventional cellulosic absorbents.
The second absorbent member 20 of the absorbent core 16
typically has a basis weight greater than that of the other
absorbent
members. The basis weight of the second absorbent member
20
generally ranges from about 50 grams per square meter (gsm)
to about
300 gsm and preferably is from about 100 gsm to about 200
gsm. Most
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preferably, the second absorbent member 20 has a basis weight of at
least about 1.5 times greater than that of the third absorbent
member 22.
The third absorbent member 22 is positioned between the second
absorbent member 20 and the baffle 14. The third absorbent member 22
has a high wicking capacity especially for menses, and can be
constructed of a fine pore fabric. Preferably, the third absorbent
member 22 is a meltblown material having excellent menses
distribution properties. Meltblown is taught in U.S. Patentw - -
No. 4,798,603 issued to Meyer et al. and assigned to the present
assignee.
The first absorbent member 18 generally serves as a fluid
transfer member to allow the body fluid to be wicked downward in the
z-direction and away from the cover 12 so that the cover 12 retains a
dry and comfortable feel to the user. The second absorbent member 20
initially accepts fluid from the first absorbent member 18 and then
wicks the fluid along it's length and width before releasing the
fluid to the third absorbent member 22. The third absorbent
member 22 then wicks the fluid along its length and width utilizing a
greater extent of the absorbent capacity. Therefore, the third
absorbent member 22 can become completely saturated before the fluid
is taken up by the second absorbent member 20. This action provides
a good post-use visual signal to the user that the fluid is staying
in the bottom of the sanitary napkin 10, thereby reinforcing the
in-use visual signal conveyed to the user. The fluid is also being
wicked along the second absorbent member 20 and the third absorbent
member 22 keeping the fluid away from the edges of the sanitary
napkin 10. This allows for a greater utilization of the absorbent
core 16 and helps reduce the likelihood of side leakage.
Referring to Fig. 2, an alternative embodiment of a sanitar-y
napkin 10' is shown. The materials used in the sanitary napkin 10'
are similar to that of Fig. 1 except for the inclusion of a fourth
absorbent member 24. The second absorbent member 20 is C-folded and
has two oppositely aligned longitudinal edges which are spaced apart
preferably forming a longitudinal gap or groove therebetween. The
C-fold enables the second absorbent member 20 to flex, thereby
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allowing the sanitary napkin 10' to conform and stay in
intimate
contact with a user's body in an area approximate the pudendum.
It
is a known fact that, if an absorbent article can be kept
in constant
contact with the body the likelihood of leakage is, greatly
minimized.
The gap has an advantage in that it allows a direct route
to the
fourth absorbent member 24, which is located within the
C-folded
second absorbent member 20. This unobstructed pathway is
especially
useful when the body fluid is menses, because there is
provided a
clear path to allow the movement of the viscous fluid from
the first
absorbent member 18 down into the fourth absorbent member
24. A
pathway which allows for rapid penetration of the body
fluid into the
center of the absorbent core 16 is highly advantageous
in keeping the
cover 12 dry and providing a no leak product. The fourth
absorbent
member 24 is positioned within the C-folded second absorbent
member 20 and has a greater wicking capacity than the second
absorbent member 20 but less than the wicking capacity
of the third
absorbent member 22. The third absorbent member 22 is similar
to
that described above for Fig. 1.
The fourth absorbent member 24 can consist of one or more
layers
of a non-wet stable material such as a single layer of
tissue, such
as shown in Fig. 3, or tissue folded upon itself to farm
an effective
multi-layered absorbent member. As shown in Fig. 2, an
E-folded
wet-laid and through dried creped tissue works well in
that it is
easy to manufacture and fold. The tissue can have a basis
weight
ranging from about 10 gsm to about 200 gsm, desirably from
about 20
gsm to about 150 gsm, and more preferably less than about
75 gsm.
Regardless of the basis weight of a non-folded tissue,
desirably the
cumulative basis weight of the tissue will be less than
about 400 gsm
and preferably less than about 200 gsm. For example, a
tissue having
a basis weight of 100 gsm folded in half would have a cumulative
basis weight of 200 gsm.
The tissue can be formed from hardwood and/or softwood
fibers.
The tissue has a fine pore structure and provides an excellent
wicking capacity especially for menses. The fourth absorbent
member 24 can have a width approximately equal to, less
than or
greater than the width of the first absorbent member 18.
It should
be noted that the fourth absorbent member 24 can have a
width equal
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CA 02197494 2003-O1-07
to the width of a second absorbent member 20 if desired. The length
of the fourth absorbent member 24 can range from between about 127 mm
to about 304 mm.
It has been discovered that the improved absorbent structure
provides for increased absorbent utilization as well as providing an
overall crush resistance to the thin sanitary napkin 10, 10' or 10".
Crush resistance is important to the proper fit of the sanitary
napkin 10, 10' or 10" to the body of the wearer.. The overall
structure of the present absorbent core 16 allows the absortrent-
core 16 to resist bunching and twisting during use. The absorbent
core 16 also displays excellent "wet resiliency." By "wet
resiliency" it is meant that the sanitary napkin 10 will not compress
less than about 50 percent of its initial width when subjected to a
30 ml insult of distilled water and a side compression force of 250
grams according to the following procedure.
Referring now to Fig. 4, a test device 100 which can be used for
analysis of the sanitary napkin 10 includes two 12.7 mm thick
vertical support pieces of clear LEXAN plastic walls 102 and 104
connected vertically on a 101.6 mm by 114.3 mm having a 60 mm
diameter hole centered in the base 106. There is a 14.3 mm wide gap
between the vertical, walls 102 and 104. The vertical walls 102 and
104 measured about 120.65 rmn wide by about 73 mm high when measured
from the top of the base. The test device 100 was used to hold the
sanitary napkin 10 vertically. A 250 gram brass block 108 measuring
about 44.45 nm wide by about 50.8 mm high by about 12.7 mm thick was
used to compress the sanitary napkin 10 before and after water is
absorbed.
The sample pads consisted of a commercial product NEW FREEDOM~
UltraThin with StayPut Tabs (with tabs removed to form straight
longitudinal sides) available from Kimberly-Clark Corporation;
Prototype A which is constructed having a Sultex cover, a 40 gsm
PRISM transfer layer, an absorbent core consisting of 100 gsm coform
C-folded around an E-folded piece of 32 gsm tissue, a single ply of
60 gsm meltblown is positioned below the coform/tissue composite; and
having a standard 1 mil polyethylene baffle; and Prototype B is
constructed having a Sultex cover, a 40 gsm PRISM transfer layer, an
absorbent core consisting of 100 gsm coform C-folded around an
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WO 96106591 PCT/U595I09244
E-folded piece of 32 gsm tissue; under this composite is two plies of
the 32 gsm tissue; and having a standard 1 mil polyethylene
baffle.
The sample pads were prepared for testing by removing the
protective paper strip from the garment attachment adhesive.
The
garment adhesive is then deactivated by lightly covering
the adhesive
with talc known in the art for this purpose. Prior to insulting
the
sample pads with water, the pads width is measured as well
as their
"dry compression." The dry compression was obtained by holding
the
brass block 108 (with its longest dimension vertically)
above the
test sample - which is held on its side in the test device
- so that
the block 108 makes contact with the side of the test sample.
The
block 108 is released approximately at the mid-section of
the
sanitary napkin 10 and the dry compression measurement is
taken from
the top of the base 106 of the test device 100 to the bottom
mid-point of the brass block 108.
To measure wet compression, this test is repeated after
each
test sample is insulted with 30 milliliters (mls) of ambient
temperature (about 20C) water and allowed to remain undisturbed
for
5 minutes. The water was introduced to the samples at a
rate of 15
mls/minute. This is achieved using a Masterflex~ Console
Drive pump,
purchased from Cole-Parmer Instrument Company, Chicago,
Illinois,
60648. The water is pumped through #14 clear Tygon tubing,
also
available from Cole-Parmer. The results appear in Table
1.
TABLE 1
Pad Dry Wet Wet Abs.
roduct Width Compress. Comoress.Recovery Caoacity
U.S. Tabbed 84 mm 56 mm 46 mm 67 mm 49 m1
Ultrathin
(Foam Insert)
Prototype A 82 mm 51 mm 46 mm 58 mm 52 ml
Prototype B 79 mm 51 mm 25 mm 27 mm 75 ml
(Tissue Core)
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W O 96106591 PCT/US95109244
~~.~'~ ~~ 4
1
The wet resiliency measurement was taken 5 seconds after the
brass block 108 is removed from the sample sanitary napkin 10.
Tests were conducted tn determine the wicking capacities of the
various materials of different absorbent articles, specifically
sanitary napkins. The test procedure determined the wicking capacity
of the various materials using a dye solution which was dispensed at
a flow rate of 3 ~ .5 milliliters (m1)/30 seconds. Measurements were
taken at two different times, at 30 seconds to establish an initial
insult and at 5 minutes after initial insult. The equipment and
materials needed for the test are as follows:
1. an automated pump capable of dispensing 3 ~ .5 ml in 30
seconds. An automated Cole Parmer-Masterflex~ pump, available
from Cole-Parmer Instrument Company, Chicago, Illinois 60648
works well;
2. a 1,000 ml capacity Pyrex graduate with 10 ml graduation;
3. a ring stand - 15 inches (381 mm) high;
4. a needle, having a 1/8 inch (3 mm) tip, mounted to the ring
stand;
5. Masterflex Tygon tubing, #14, available from Cole-Parmer
Instrument Company;
6. 40 ml of a dye solution formed from mixing 16.7 grams of blue
dye, No. 1 powder, available from the Warner-Jenkinson Division
of Universal Foods Corporation located at 2526 Baldwin Street,
PO Box 14538, St. Louis, MO 63178-4538, which has been mixed
with 1,000 ml of distilled water;
7. 900 ml of distilled water;
8. a stopwatch, readable to 0.1 second; and
9. a metric ruler.
Before starting the test, 40 ml of the dye solution is gently
swirled with 900 m1 of distilled water in the 1000 ml capacity Pyrex
graduate.
The samples to be tested should be conditioned as follows:
first, each sample should be removed from a protective package, if
the sample is retained in a package. Each sample should then be held
at a temperature of 73°F ~ 1°F and at a relative humidity of 50%
~ 2%
for at least 2 hours. After being conditioned, a 2 by 6 inch
(52 mm x 152 mm) specimen is cut from the center of each sample. The
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WO 96106591 PCT/US95109244
9~
longer dimension corresponds to the length of the article
from which
it is cut.
The test procedure for each specimen is as follows: each
2 by 6
inch specimen is laid on a table with it's body side surface
facing
up. The tip of the needle is centered over the specimen.
The switch
which controls the flow of the dye solution from the pump
is turned
on to allow the dye solution to flow onto the center of
the specimen.
The stopwatch is started as soon as the dye solution drips
onto the
specimen. At 30 seconds, the switch to the pump is turned
off and
the stopwatch is simultaneously stopped. This time period
represents
what is referred to in the Tables as the "initial insult"
and the
amount of fluid dispensed should be 3 ml. As quickly as
possible,
the cover is removed from the specimen. The length and
width of the
fluid stain on each absorbent member is measured with the
metric
ruler. Each absorbent member is carefully peeled apart
from the
adjacent member in order to measure the fluid stain. This
measurement is denoted and recorded and represents the
initial insult
of the dye solution. All of the absorbent members and the
cover are
then returned to their original position and the stopwatch
is
started. Five minutes thereafter the stopwatch is stopped.
As
quickly as possible, the cover is removed from the specimen.
The
length and width of the fluid stain on the absorbent members,
as
described above, are measured and recorded. These measurements
are
denoted and recorded as the "5 minute after insult" reading.
This is
the final measurement.
The data appearing in Table 2 below was obtained using
the above
described test procedure.
Four (4) prototypes of the present invention were tested.
The
prototypes are labeled as "1," "2," "3" and "4." The construction
of
each pad is as follows:
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WO96106591 PCT/US95/09244
'
;.
TABLE 2
Stain Stain Length
Length
Ratio Ratio 5 min.
After
Product Ratio of Members 3 Insult AfterInsult
ml
1 coform (2): PRISM 4.87 5.4
(I)
tissue (3): coform 2.01 2.68 -
(2)
meltblown {4): (3) .69 .50
tissue
2 coform (2): PRISM 3.87 4.14 ,
(1)
tissue (3): coform 1.44 2.02
(2)
meltblown (4): (3) 1.09 1.01
tissue
3 coform (2): PRISM 3.23 3.61
(1)
meltblown (3): (2) 2.18 2.69
coform
4 coform (2): PRISM 5.6 5.96
(1)
meltblown (3): (2) 1.26 1.64
coform
tissue {4): meltblown (3) .91 .97
Product Composition 1: Sultex, PRISM, C-folded coform, E-folded
tissue (inside coform), meltblown.
Product Composition 2: Sultex, PRISM, C-folded coform, E-folded
tissue (below coform), meltblown.
Product Composition 3: Sultex, PRISM, C-folded coform, meltblown.
Product Composition 4: Sultex, PRISM, C-folded coform, meltblown,
E-folded tissue below meltblown.
Sultex: Cover material available from Pantex S.R.L.
Agliana Pistoia, Italy.
PRISM: 40 gsm basis weight.
coform: 100 gsm basis weight of a 60/40 blend of
polypropylene and pulp manufactured by
Kimberly-Clark Corporation.
meltblown: 60 gsm microfibers manufactured by
Kimberly-Clark Corporation.
It can be readily seen from the data that after 5 minutes from
the initial insult, the length, as represented by a ratio of stain
lengths, of the fluid stain in the meltblown absorbent members was
greater than that of the preceding absorbent members, except for
Prototype 1. This can be explained by the positioning of the tissue
inside the coform. This arrangement of the absorbent members, allows
the fluid to transfer rapidly along the tissue within the coform
indicating a false relative wicking rate of the absorbent material.
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WO 96!06591 PCT/U595109244
While the invention has been described in conjunction with
several specific embodiments, it is to be understood that many
alternatives, modifications and variations will be apparent to those
skilled in the art in light of the aforegoing description.
Accordingly, this invention is intended to embrace all such
alternatives, modifications and variations which fall within the
spirit and scope of the appended claims.
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