U.S. patent application number 14/970708 was filed with the patent office on 2016-04-14 for absorbent article with improved garment-like character.
The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to Mark James Kline, Donald Carroll Roe.
Application Number | 20160100994 14/970708 |
Document ID | / |
Family ID | 42154805 |
Filed Date | 2016-04-14 |
United States Patent
Application |
20160100994 |
Kind Code |
A1 |
Roe; Donald Carroll ; et
al. |
April 14, 2016 |
ABSORBENT ARTICLE WITH IMPROVED GARMENT-LIKE CHARACTER
Abstract
A disposable absorbent article may include a chassis, an
absorbent core, a pair of elastically elongatable ears and a pair
of fastening tabs. The elastically elongatable ears and the
fastening tabs have a transverse axis. The ears are connected to
the chassis such that the transverse axis of the fastening tabs is
located in specific portions of the article. The absorbent core is
free of cellulosic fibers.
Inventors: |
Roe; Donald Carroll; (West
Chester, OH) ; Kline; Mark James; (Okeana,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Family ID: |
42154805 |
Appl. No.: |
14/970708 |
Filed: |
December 16, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13134816 |
Jun 17, 2011 |
|
|
|
14970708 |
|
|
|
|
Current U.S.
Class: |
604/366 ;
604/385.16 |
Current CPC
Class: |
A61F 2013/530963
20130101; A61F 2013/530525 20130101; A61F 2013/5395 20130101; A61F
13/4906 20130101; A61F 2013/530131 20130101; A61F 13/496 20130101;
A61F 13/514 20130101; A61F 13/5622 20130101; A61F 13/5633 20130101;
A61F 2013/15146 20130101; A61F 13/49014 20130101; A61F 13/58
20130101; A61F 13/511 20130101; A61F 2013/530554 20130101; A61F
2013/530518 20130101; A61F 13/539 20130101; A61F 13/51464
20130101 |
International
Class: |
A61F 13/496 20060101
A61F013/496; A61F 13/56 20060101 A61F013/56; A61F 13/58 20060101
A61F013/58; A61F 13/514 20060101 A61F013/514; A61F 13/539 20060101
A61F013/539; A61F 13/49 20060101 A61F013/49; A61F 13/511 20060101
A61F013/511 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2010 |
CA |
2692679 |
Claims
1. A disposable absorbent article comprising: a) a chassis having a
front region with a front edge, a rear region with a back edge, a
crotch region between the front region and the rear region, and a
pair of opposing longitudinal edges, said chassis comprising an
absorbent core having front and back edges; b) first and second
elastically elongatable ears, each of said first and second
elastically elongatable ears having upper and lower edges and a
transverse axis, each of said upper and lower edges having proximal
and distal ends, said first and second elastically elongatable ears
defining a back section of said absorbent article that is present
between said back edge of said chassis and a line connecting the
respective proximal ends of the lower edge of said first and second
elastically elongatable ears wherein the upper and lower edges of
said first and second elongatable ears are asymmetric relative to
the transverse axis of the elastically elongatable ears; and c)
first and second fastening tabs respectively connected to a distal
portion of said first and second elastically elongatable ears, each
of said first and second fastening tabs having upper and lower
edges and a transverse axis, wherein said upper and lower edges of
said fastening tabs are asymmetric relative to the transverse axis
of the fastening tabs, wherein the first fastening tab is outboard
of the first elastically elongatable ear and the second fastening
tab is outboard of the second elastically elongatable ear, wherein
the transverse axis of the first and second fastening tabs overlap
substantially with the transverse axis of the first and second
elongatable ears respectively; wherein said absorbent core is
substantially cellulose free; wherein the transverse axis of the
fastening tabs and the back edge of the absorbent core are
separated by a longitudinal distance of less than 20 mm; wherein
the distance between the upper and lower proximal ends of the first
elastically elongatable ear is at least 50% greater than the
distance between the upper and lower distal ends of the first
elastically elongatable ear; and wherein the distance between the
upper and lower proximal ends of the second elastically elongatable
ear is at least 50% greater than the distance between the upper and
lower distal ends of the second elastically elongatable ear.
2. The disposable absorbent article of claim 1, wherein the back
edge of the chassis and the back edge of the absorbent core are
separated by a longitudinal distance of less than 100 mm.
3. The disposable absorbent article of claim 1, wherein said
absorbent core is disposed between a liquid pervious topsheet and a
liquid impervious backsheet.
4. The disposable absorbent article of claim 3, wherein said
absorbent core comprises a first layer of a nonwoven fibrous
material having upper and lower surfaces, a layer of a
thermoplastic adhesive material and an absorbent material between
the upper surface of the first layer of the nonwoven fibrous
material and the layer of thermoplastic adhesive material.
5. The disposable absorbent article of claim 4, wherein the upper
surface of the first layer of nonwoven material comprises a
plurality of regions that are each in direct facial relationship
with a significant amount of said absorbent material.
6. The disposable absorbent article of claim 5, wherein said upper
surface of said first layer of nonwoven fibrous material comprises
a plurality of regions that are each in facial relationship with an
insignificant amount of said absorbent material.
7. The disposable absorbent article of claim 6, wherein said
absorbent core further comprises a second layer of a nonwoven
fibrous material having upper and lower surfaces such that said
absorbent material and said layer of thermoplastic adhesive
material are between said upper surface of said first layer of
nonwoven fibrous material and said second layer of said nonwoven
fibrous material.
8. The disposable absorbent article of claim 7, wherein the lower
surface of the second layer of nonwoven material comprises a
plurality of regions that are each in direct facial relationship
with a significant amount of additional absorbent material.
9. The disposable absorbent article of claim 8, wherein said lower
surface of said second layer of nonwoven fibrous material comprises
a plurality of region that are each in facial relationship with an
insignificant amount of said additional absorbent material.
10. The disposable absorbent article of claim 9, wherein at least
some of the regions of said upper surface of the first nonwoven
fibrous material that are in direct facial relationship with an
absorbent material are in direct facial relationship with at least
corresponding regions of the lower surface of the second nonwoven
fibrous material that are in facial relationship with an
insignificant amount of absorbent material.
11. The disposable absorbent article of claim 7, wherein said first
layer of nonwoven fibrous material and said second layer of
nonwoven fibrous material are made of different nonwoven
materials.
12. The disposable absorbent article of claim 7, wherein said first
layer of nonwoven fibrous material and said second layer of
nonwoven fibrous material each have a surface energy and wherein
the surface energy of said first layer is different from the
surface energy of said second layer.
13. The disposable absorbent article of claim 12, wherein said
second layer of nonwoven fibrous material comprises a
surfactant.
14. The disposable absorbent article of claim 13, wherein said
article comprises a middle section having an average caliper that
is greater than the average caliper of said back section.
Description
FIELD OF INVENTION
[0001] This invention relates to absorbent articles such as diapers
having fastener bearing ears that yield a more garment-like
article. The absorbent article may have improved functional
characteristics and communicative properties.
BACKGROUND OF THE INVENTION
[0002] It has long been known that absorbent articles such as
conventional taped diapers offer the benefit of receiving and
containing urine and/or other bodily exudates. To effectively
contain exudates, the article should provide a snug fit around the
waist and legs of a wearer. Absorbent articles are known to have a
chassis comprising a topsheet, a backsheet, and an absorbent core.
Absorbent articles such as conventional taped diapers generally
include a front and a rear waist section releasably and/or
refastenably connected by a fastening system. The fastening system
generally comprises an engaging member and a receiving member. The
engaging member may be an adhesive tape, a hook bearing tape, a
cohesive tape, or other like structure. The receiving member may be
an element or zone on the article that may receive the engaging
member such as a polymer film landing zone (viz., for receipt of
the adhesive or cohesive tape) or a loop bearing surface (viz., for
receipt of the hook bearing tape). The engaging member may be
joined to the receiving member thereby interconnecting the rear
waist section to the front waist section and thereby forming a
waist opening and a pair of leg openings.
[0003] Current diaper designs frequently include the use of
extensible ears. Back ears may extend laterally from the
longitudinal edge of the rear waist section of the chassis. The
engaging member of the fastening system may be attached to the back
ear. In the case of front-fastened or taped designs, when the
fastening system is engaged to the receiving member on the front
waist region, the back ear serves as an interconnecting member
between the front waist section and the rear waist section, which
together form a waist opening and pair of leg openings. Back ears
may be constructed to provide a degree of elastic recovery.
Elasticized back ears allow the diaper to provide a more customized
fit. Furthermore, the elastic capability allows the diaper to
adjust to the forces exerted by the wearer without causing
permanent deformation of the diaper or discomfort for the wearer of
the diaper. Elasticity is typically imparted to the back ears by
incorporating elastic materials into the ear. Due to the high cost
of elastomeric materials, a common practice is to construct elastic
ears as discrete components that are attached to the chassis (i.e.,
the main absorbent assembly to which other components may be
disposed) resulting in a multipiece diaper. While this practice
results in the efficient and cost-effective use of elastic
materials, it is not without problems.
[0004] One problem seen in multipiece diapers is "tophatting." A
"tophat" is a portion of the front or rear waist region that
extends beyond the uppermost edge of the front or back ear toward
the waist edge of the diaper. When a multipiece diaper is
appropriately worn, the waist edge of the diaper in the front waist
region and the rear waist region are substantially linear or
slightly curvilinear. As the waist edge transitions from the rear
waist region to the attached back ear, the waist edge may abruptly
drop and then continue in a linear or curvilinear manner following
the upper edge of the back ear. This "drop" from the waist edge in
the front waist region or the rear waist region to the upper edge
of the back ear may be one centimeter or greater. When worn, a
taped diaper with the drop in the waist edge appears to have a
notch cut from its side. The waist edge of such a diaper may have a
stair step-like appearance.
[0005] Tophatting may have an adverse impact on the fit
characteristics of a multipiece diaper. Generally, a diaper exerts
a circumferential line of tension around a wearer's torso. This
tension may be a product of the elastic back ear being strained.
With a multipiece diaper exhibiting a tophat, the line of tension
is located well below the waist edge because the line of tension is
transmitted only along or through a continuous, unbroken path about
the diaper. Since the tension-generating elasticized ear and
fastening system are significantly remote from the waist edge, the
line of tension is likewise remote from (e.g., generally lower
than) the waist edge in the front waist region and rear waist
region.
[0006] Fit and functionality problems may result from the line of
tension being located remotely from the waist edge. For example,
the front waist region and/or rear waist region of the diaper may
exhibit sagging or fold-over. Sagging is the wrinkled, loose,
gapped, or puckered configuration that the diaper exhibits when it
is not under tension. Fold-over is the inversion of at least a
portion of the diaper such that a body-facing surface of the diaper
becomes garment-facing. Similar to sagging, fold-over may occur
when the portion of the diaper is not under tension. Fold-over and
sagging may also impair the gasketing function of the waist edge.
For example, the interface of the waist edge and the wearer's waist
is susceptible to leakage particularly when the wearer is in a
prone or supine position. Fold-over and sagging can reduce the
surface area of the diaper that is in close contact with the wearer
at this interface which may result in leakage.
[0007] Furthermore, fold-over and sagging are aesthetically
undesirable. Fold-over and sagging result in a diaper that is
sloppy looking during wear. This, in turn, may communicate to the
consumer that the diaper is of low quality which may be contrary to
the high quality of functional characteristics such as absorbency
or leakage prevention.
[0008] Top-hatting and the resulting lack of a smooth, continuous,
and circumferential waist edge communicate other unwanted messages
to the consumer or wearer of the diaper. For example, tophatting
may be a readily visible signal that the product is a diaper. For
many wearers such as children being toilet trained or incontinent
youths and adults, a stigma is attached to having to wear a diaper.
To alleviate this concern, the diaper should communicate a message
of being garment-like or underwear-like. In other words, it is
desirable that the diaper not appear diaper-like. However,
tophatting and discontinuous waist edges are apparent signals of a
diaper.
[0009] Accordingly, it would be desirable to provide a diaper
having a back ear that eliminates or reduces tophatting in a
multipiece diaper. Furthermore, it is desirable that the diaper
exhibit a smooth, continuous, circumferential waist edge without
discontinuities or drops. It is desirable that the diaper exhibit a
line of tension, which is provided at least in part by discrete
ears, as close to the waist edge as possible. It is also desirable
that the diaper communicate a message of being garment-like without
the readily apparent visual cue (e.g., waist discontinuity) of
being a diaper.
SUMMARY OF THE INVENTION
[0010] The present invention relates to disposable absorbent
article that comprises a chassis having a front region with a front
edge, a rear region with a back edge, a crotch region between the
front region and the rear region, and a pair of opposing
longitudinal edges. The chassis includes an absorbent core having
front and back edges. The article also includes first and second
elastically elongatable ears, each of the first and second ears
having upper and lower edges and a transverse axis, each of the
upper and lower edges having proximal and distal ends. The first
and second ears define a back section of the absorbent article that
is present between the back edge of the chassis and a line
connecting the respective lower ends of the lower edge of the first
and second ears. The article also includes first and second
fastening tabs respectively connected to a distal portion of the
first and second elastically elongatable ears, each of the first
and second fastening tabs having upper and lower edges and a
transverse axis. The upper and lower edges of the fastening tabs
are asymmetric relative to the transverse axis of the fastening
tabs. The back section of the chassis has an Average. Peak Bending
Force of less than 0.08N.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A is a plan view of an exemplary diaper in a flat,
uncontracted state with back ears.
[0012] FIG. 1B is a plan view of an exemplary diaper in a flat,
uncontracted state with front ears and back ears.
[0013] FIG. 1C is a plan view of an exemplary diaper in a flat,
uncontracted state with back ears formed by a belt.
[0014] FIG. 2A is a perspective view of the diaper of FIG. 1A in a
fastened configuration as would be exhibited during wear.
[0015] FIG. 2B is a perspective view of the diaper of FIG. 1B in a
fastened configuration as would be exhibited during wear.
[0016] FIG. 3A is a magnified planar, side view of the diaper of
FIG. 2A.
[0017] FIG. 3B is a magnified planar, side view of the diaper of
FIG. 2B.
[0018] FIG. 4 is a perspective view of a suitable grip for use in
the Metric Test Method.
[0019] FIGS. 5A-C depict suitable edge determinations.
[0020] FIG. 6 is a schematic body facing surface view of an
absorbent article according to one embodiment of the invention.
[0021] FIG. 7 depicts an elastically elongatable ear and a
fastening tab.
[0022] FIG. 8 is a schematic cross section view of an example of an
absorbent core suitable in one embodiment of the invention.
[0023] FIG. 9 is a schematic cross section view of another example
of an absorbent core suitable in one embodiment of the
invention.
[0024] FIG. 10 is a schematic cross section view of another example
of an absorbent core suitable in one embodiment of the
invention.
[0025] FIG. 11 is a schematic body facing surface view of an
absorbent article with an absorbent core according to one
embodiment of the invention.
[0026] FIG. 12 is a schematic body facing surface view of an
absorbent article with an absorbent core according to another
embodiment of the invention.
[0027] FIG. 13 is a schematic body facing surface view of an
absorbent article with an absorbent core according to another
embodiment of the invention.
[0028] FIG. 14 is a schematic body facing surface view of an
absorbent article with an absorbent core according to another
embodiment of the invention.
[0029] FIG. 15 is a schematic body facing surface view of an
absorbent article with an absorbent core according to another
embodiment of the invention.
[0030] FIG. 16 is an elevation view showing an apparatus for
testing the bending stiffness of materials;
[0031] FIG. 17 is a front elevation view showing a plunger for use
with the apparatus of FIG. 16;
[0032] FIG. 18 is a side elevation view showing a plunger for use
with the apparatus of FIG. 16; and
[0033] FIG. 19 is a graph showing Peak bending load and slope
calculation areas on bending curve.
DETAILED DESCRIPTION OF THE INVENTION
[0034] As used herein, the following terms shall have the meaning
specified thereafter: "Tophat" is a portion of a front or rear
waist region of a diaper that extends beyond the uppermost edge of
a front or back ear toward the waist edge of the diaper.
[0035] "Disposable," in reference to absorbent articles, means that
the absorbent articles are generally not intended to be laundered
or otherwise restored or reused as absorbent articles (i.e., they
are intended to be discarded after a single use and, preferably, to
be recycled, composted or otherwise discarded in an environmentally
compatible manner).
[0036] "Absorbent article" refers to devices which absorb and
contain body exudates and, more specifically, refers to devices
which are placed against or in proximity to the body of the wearer
to absorb and contain the various exudates discharged from the
body. Exemplary absorbent articles include diapers, training pants,
pull-on pant-type diapers (i.e., a diaper having a pre-formed waist
opening and leg openings such as illustrated in U.S. Pat. No.
6,120,487), refastenable diapers or pant-type diapers, incontinence
briefs and undergarments, diaper holders and liners, feminine
hygiene garments such as panty liners, absorbent inserts, and the
like.
[0037] "Proximal" and "Distal" refer respectively to the location
of an element relatively near to or far from the longitudinal or
lateral centerline of a structure (e.g., the proximal edge of a
longitudinally extending element is located nearer to the
longitudinal centerline than the distal edge of the same element is
located relative to the same longitudinal centerline).
[0038] "Body-facing" and "garment-facing" refer respectively to the
relative location of an element or a surface of an element or group
of elements. "Body-facing" implies the element or surface is nearer
to the wearer during wear than some other element or surface.
"Garment-facing" implies the element or surface is more remote from
the wearer during wear than some other element or surface (i.e.,
element or surface is proximate to the wearer's garments that may
be worn over the disposable absorbent article).
[0039] "Longitudinal" refers to a direction running substantially
perpendicular from a waist edge to an opposing waist edge of the
article and generally parallel to the maximum linear dimension of
the article. Directions within 45 degrees of the longitudinal
direction are considered to be "longitudinal"
[0040] "Lateral" refers to a direction running from a longitudinal
edge to an opposing longitudinal edge of the article and generally
at a right angle to the longitudinal direction. Directions within
45 degrees of the lateral direction are considered to be
"lateral."
[0041] "Disposed" refers to an element being located in a
particular place or position.
[0042] "Joined" refers to configurations whereby an element is
directly secured to another element by affixing the element
directly to the other element and to configurations whereby an
element is indirectly secured to another element by affixing the
element to intermediate member(s) which in turn are affixed to the
other element.
[0043] "Film" refers to a sheet-like material wherein the length
and width of the material far exceed the thickness of the material.
Typically, films have a thickness of about 0.5 mm or less.
[0044] "Water-permeable" and "water-impermeable" refer to the
penetrability of materials in the context of the intended usage of
disposable absorbent articles. Specifically, the term
"water-permeable" refers to a layer or a layered structure having
pores, openings, and/or interconnected void spaces that permit
liquid water, urine, or synthetic urine to pass through its
thickness in the absence of a forcing pressure. Conversely, the
term "water-impermeable" refers to a layer or a layered structure
through the thickness of which liquid water, urine, or synthetic
urine cannot pass in the absence of a forcing pressure (aside from
natural forces such as gravity). A layer or a layered structure
that is water-impermeable according to this definition may be
permeable to water vapor, i.e., may be "vapor-permeable." As is
well known in the art, a common method for measuring the
permeability to water, urine, or synthetic urine of the materials
typically used in absorbent articles is a hydrostatic pressure
test, also called a hydrostatic head test or simply a "hydrohead"
test. Suitable well known compendial methods for hydrohead testing
are approved by IVDA (formerly the International Nonwovens and
Disposables Association, now The Association of the Nonwoven
Fabrics Industry) and EDANA (European Disposables And Nonwovens
Association).
[0045] "Extendibility" and "extensible" mean that the width or
length of the component in a relaxed state can be extended or
increased.
[0046] "Elasticated" and "elasticized" mean that a component
comprises at least a portion made of elastic material.
[0047] "Elongatable material," "extensible material," or
"stretchable material" are used interchangeably and refer to a
material that, upon application of a biasing force, can stretch to
an elongated length of at least 150% of its relaxed, original
length (i.e. can stretch to 50% more than its original length),
without complete rupture or breakage as measured by EDANA method
20.2-89. In the event such an elongatable material recovers at
least 40% of its elongation upon release of the applied force, the
elongatable material will be considered to be "elastic" or
"elastomeric." For example, an elastic material that has an initial
length of 100 mm can extend at least to 150 mm, and upon removal of
the force retracts to a length of at least 130 mm (i.e., exhibiting
a 40% recovery). In the event the material recovers less than 40%
of its elongation upon release of the applied force, the
elongatable material will be considered to be "substantially
non-elastic" or "substantially non-elastomeric. For example, an
elastic material that has an initial length of 100 mm can extend at
least to 150 mm, and upon removal of the force retracts to a length
of at least 145 mm (i.e., exhibiting a 10% recovery).
[0048] "Elastomeric material" is a material exhibiting elastic
properties. Elastomeric materials may include elastomeric films,
scrims, nonwovens, and other sheet-like structures.
[0049] "Outboard" and "inboard" refer respectively to the location
of an element disposed relatively far from or near to the
longitudinal centerline of the diaper with respect to a second
element. For example, if element A is outboard of element B, then
element A is farther from the longitudinal centerline than is
element B.
[0050] "Pant" refers to disposable absorbent articles having a
pre-formed waist and leg openings. A pant may be donned by
inserting a wearer's legs into the leg openings and sliding the
pant into position about the wearer's lower torso. Pants are also
commonly referred to as "closed diapers", "prefastened diapers",
"pull-on diapers", "training pants" and "diaper-pants."
[0051] "Prefastened" refers to a disposable absorbent article that
is manufactured such that the fastening system is in an engaged or
fastened configuration.
[0052] "Consumer Commercial Good" refers to an item produced and
distributed in large quantities and that the item may be purchased
by a consumer through a retail establishment accessible to the
public.
[0053] "Linear Projection" is the linear extension of an edge
beyond the end point of the edge.
[0054] FIG. 1 is a plan view of an exemplary, non-limiting
embodiment of a diaper 20 of the present invention in a flat,
uncontracted state (i.e., without elastic induced contraction). The
garment-facing surface 120 of the diaper 20 is facing the viewer.
The diaper 20 includes a longitudinal centerline 100 and a lateral
centerline 110. The diaper 20 may comprise a chassis 22. The diaper
20 and chassis 22 are shown to have a front waist region 36, a rear
waist region 38 opposed to the front waist region 36, and a crotch
region 37 located between the front waist region 36 and the rear
waist region 38. The waist regions 36 and 38 generally comprise
those portions of the diaper 20 which, when worn, encircle the
waist of the wearer. The waist regions 36 and 38 may include
elastic elements such that they gather about the waist of the
wearer to provide improved fit and containment. The crotch region
37 is that portion of the diaper 20 which, when the diaper 20 is
worn, is generally positioned between the legs of the wearer.
[0055] The outer periphery of chassis 22 is defined by longitudinal
edges 12 and lateral edges 14. The longitudinal edges 12 may be
subdivided into a front longitudinal edge 12a, which is the portion
of the longitudinal edge 12 in the front waist region 36, and a
rear longitudinal edge 12b, which is the portion of the
longitudinal edge 12 in the rear waist region 38. The chassis 22
may have opposing longitudinal edges 12 that are oriented generally
parallel to the longitudinal centerline 100. However, for better
fit, longitudinal edges 12 may be curved or angled to produce, for
example, an "hourglass" shape diaper when viewed in a plan view.
The chassis 22 may have opposing lateral edges 14 that are oriented
generally parallel to the lateral centerline 110.
[0056] The chassis 22 may comprises a liquid permeable topsheet 24,
a backsheet 26, and an absorbent core 28 between the topsheet 24
and the backsheet 26. The absorbent core 28 may have a body-facing
surface and a garment facing-surface. The topsheet 24 may be joined
to the core 28 and/or the backsheet 26. The backsheet 26 may be
joined to the core 28 and/or the topsheet 24. It should be
recognized that other structures, elements, or substrates may be
positioned between the core 28 and the topsheet 24 and/or backsheet
26. In certain embodiments, the chassis 22 comprises the main
structure of the diaper 20 with other features may added to form
the composite diaper structure. While the topsheet 24, the
backsheet 26, and the absorbent core 28 may be assembled in a
variety of well-known configurations, preferred diaper
configurations are described generally in U.S. Pat. Nos. 3,860,003;
5,151,092; 5,221,274; 5,554,145; 5,569,234; 5,580,411; and
6,004,306.
[0057] The topsheet 24 is generally a portion of the diaper 20 that
may be positioned at least in partial contact or close proximity to
a wearer. Suitable topsheets 24 may be manufactured from a wide
range of materials, such as porous foams; reticulated foams;
apertured plastic films; or woven or nonwoven webs of natural
fibers (e.g., wood or cotton fibers), synthetic fibers (e.g.,
polyester or polypropylene fibers), or a combination of natural and
synthetic fibers. The topsheet 24 is generally supple, soft
feeling, and non-irritating to a wearer's skin. Generally, at least
a portion of the topsheet 24 is liquid pervious, permitting liquid
to readily penetrate through the thickness of the topsheet 24. A
particularly topsheet 24 is available from BBA Fiberweb, Brentwood,
Tenn. as supplier code 055SLPV09U.
[0058] Any portion of the topsheet 24 may be coated with a lotion
as is known in the art. Examples of suitable lotions include those
described in U.S. Pat. Nos. 5,607,760; 5,609,587; 5,635,191; and
5,643,588. The topsheet 24 may be fully or partially elasticized or
may be foreshortened so as to provide a void space between the
topsheet 24 and the core 28. Exemplary structures including
elasticized or foreshortened topsheets are described in more detail
in U.S. Pat. Nos. 4,892,536; 4,990,147; 5,037,416; and
5,269,775.
[0059] The absorbent core 28 may comprise a wide variety of
liquid-absorbent materials commonly used in disposable diapers and
other absorbent articles. Examples of suitable absorbent materials
include comminuted wood pulp, which is generally referred to as air
felt creped cellulose wadding; melt blown polymers, including
co-form; chemically stiffened, modified or cross-linked cellulosic
fibers; tissue, including tissue wraps and tissue laminates;
absorbent foams; absorbent sponges; superabsorbent polymers;
absorbent gelling materials; or any other known absorbent material
or combinations of materials. In one embodiment, at least a portion
of the absorbent core is substantially cellulose free and contains
less than 10% by weight cellulosic fibers, less than 5% cellulosic
fibers, less than 1% cellulosic fibers, no more than an immaterial
amount of cellulosic fibers or no cellulosic fibers. It should be
understood that an immaterial amount of cellulosic material does
not materially affect at least one of the thinness, flexibility,
and absorbency of the portion of the absorbent core that is
substantially cellulose free. Among other benefits, it is believed
that when at least a portion of the absorbent core is substantially
cellulose free, this portion of the absorbent core is significantly
thinner and more flexible than a similar absorbent core that
includes more than 10% by weight of cellulosic fibers. The amount
of absorbent material, such as absorbent particulate polymer
material present in the absorbent core may vary, but in certain
embodiments, is present in the absorbent core in an amount greater
than about 80% by weight of the absorbent core, or greater than
about 85% by weight of the absorbent core, or greater than about
90% by weight of the absorbent core, or greater than about 95% by
weight of the core. Non-limiting examples of suitable absorbent
cores are described in greater details below.
[0060] Exemplary absorbent structures for use as the absorbent core
28 are described in U.S. Pat. Nos. 4,610,678; 4,673,402; 4,834,735;
4,888,231; 5,137,537; 5,147,345; 5,342,338; 5,260,345; 5,387,207;
5,397,316; and 5,625,222.
[0061] The backsheet 26 is generally positioned such that it may be
at least a portion of the garment-facing surface 120 of the diaper
20. Backsheet 26 may be designed to prevent the exudates absorbed
by and contained within the diaper 20 from soiling articles that
may contact the diaper 20, such as bed sheets and undergarments. In
certain embodiments, the backsheet 26 is substantially
water-impermeable. Suitable backsheet 26 materials include films
such as those manufactured by Tredegar Industries Inc. of Terre
Haute, Ind. and sold under the trade names X15306, X10962, and
X10964. Other suitable backsheet 26 materials may include
breathable materials that permit vapors to escape from the diaper
20 while still preventing exudates from passing through the
backsheet 26. Exemplary breathable materials may include materials
such as woven webs, nonwoven webs, composite materials such as
film-coated nonwoven webs, and microporous films such as
manufactured by Mitsui Toatsu Co., of Japan under the designation
ESPOIR NO and by EXXON Chemical Co., of Bay City, Tex., under the
designation EXXAIRE. Suitable breathable composite materials
comprising polymer blends are available from Clopay Corporation,
Cincinnati, Ohio under the name HYTREL blend P18-3097. Such
breathable composite materials are described in greater detail in
PCT Application No. WO 95/16746 and U.S. Pat. No. 5,865,823. Other
breathable backsheets including nonwoven webs and apertured formed
films are described in U.S. Pat. No. 5,571,096. An exemplary,
suitable backsheet is disclosed in U.S. Pat. No. 6,107,537. Other
suitable materials and/or manufacturing techniques may be used to
provide a suitable backsheet 26 including, but not limited to,
surface treatments, particular film selections and processing,
particular filament selections and processing, etc.
[0062] Backsheet 26 may also consist of more than one layer. The
backsheet 26 may comprise an outer cover and an inner layer. The
outer cover may be made of a soft, non-woven material. The inner
layer may be made of a substantially water-impermeable film. The
outer cover and an inner layer may be joined together by adhesive
or any other suitable material or method. A particularly suitable
outer cover is available from Corovin GmbH, Peine, Germany as
supplier code A18AH0, and a particularly suitable inner layer is
available from RKW Gronau GmbH, Gronau, Germany as supplier code
PGBR4WPR. While a variety of backsheet configurations are
contemplated herein, it would be obvious to those skilled in the
art that various other changes and modifications can be made
without departing from the spirit and scope of the invention.
[0063] The diaper 20 may include barrier cuffs 60 and/or gasketing
cuffs 70. Gasketing cuffs 70 may also be referred to as outer leg
cuffs, leg bands, side flaps, leg cuffs, or elastic cuffs. Barrier
cuffs 60 may also be referred to as second cuffs, inner leg cuffs
or "stand-up" elasticized flaps.
[0064] The gasketing cuff 70 may be substantially inelastic or may
be elastically extensible to dynamically fit at the wearer's leg.
The gasketing cuff 70 may be formed by one or more elastic members
72 (such as elastic strands) operatively joined to the topsheet 24,
backsheet 26, or any other suitable substrate used in the formation
of the diaper 20. Suitable gasketing cuff construction is further
described in U.S. Pat. No. 3,860,003
[0065] The barrier cuff 60 may span the entire longitudinal length
of the diaper 20. The barrier cuff 60 may be formed by a flap 62
and an elastic member 64 (such as elastic strands). The flap 62 may
be a continuous extension of any of the existing materials or
elements that form the diaper 20. In other embodiments, such as
shown in FIG. 1, the barrier cuff 60 may be a discrete element. In
such embodiments, the barrier cuff 60 comprising the flap 62 and
the elastic member 64 may be formed then joined to the chassis 22
by a bond 65.
[0066] The flap 62 may comprise a variety of substrates such as
plastic films and woven or nonwoven webs of natural fibers (e.g.,
wood or cotton fibers), synthetic fibers (e.g., polyester or
polypropylene fibers), or a combination of natural and synthetic
fibers. In certain embodiments, the flap 62 may comprise a nonwoven
web such as spunbond webs, meltblown webs, carded webs, and
combinations thereof (e.g., spunbond-meltblown composites and
variants). Laminates of the aforementioned substrates may also be
used to form the flap 62. A particularly suitable flap may comprise
a nonwoven available from BBA Fiberweb, Brentwood, Tenn. as
supplier code 30926. A particularly suitable elastic member is
available from Invista, Wichita, Kans. as supplier code T262P.
Further description of diapers having barrier cuffs and suitable
construction of such barrier cuffs may be found in U.S. Pat. Nos.
4,808,178 and 4,909,803. The elastic member 64 may span the
longitudinal length of the barrier cuff 60. In other embodiments,
the elastic member 64 may span at least the longitudinal length of
the barrier cuff 60 within the crotch region 37. It is desirable
that the elastic member 64 exhibits sufficient elasticity such that
the barrier cuff 60 remains in contact with the wearer during
normal wear, thereby enhancing the barrier properties of the
barrier cuff 60. The elastic member 64 may be connected to the flap
62 at opposing longitudinal ends. In certain embodiments, the flap
62 may be folded over onto itself so as to encircle the elastic
member 64. A bond 67 may be used to secure the folded section of
the flap 62.
[0067] The barrier cuffs 60 and/or gasketing cuffs 70 may be
treated, in full or in part, with a lotion, as described above with
regard to topsheets, or may be fully or partially coated with a
hydrophobic surface coating as detailed in U.S. application Ser.
No. 11/055,743, which was filed Feb. 10, 2005.
[0068] The diaper 20 may include front ears 40 and/or back ears 42.
The ears 40, 42 may be extensible, inextensible, elastic, or
inelastic. The ears 40, 42 may be formed from nonwoven webs, woven
webs, knitted fabrics, polymeric and elastomeric films, apertured
films, sponges, foams, scrims, and combinations and laminates
thereof. In certain embodiments the ears 40, 42 may be formed of a
stretch laminate such as a nonwoven/elastomeric material laminate
or a nonwoven/elastomeric material/nonwoven laminate. Stretch
laminates may be formed by any method known in the art. For
example, the ears 40, 42 may be formed as a zero strain stretch
laminate, which includes at least a layer of non-woven material and
an elastomeric element. The elastomeric element is attached to the
layer of non-woven material while in a relaxed or substantially
relaxed state, and the resulting laminate is made stretchable (or
more stretchable over a further range) by subjecting the laminate
to an activation process which elongates the nonwoven layer
permanently, but the elastomeric element temporarily. The nonwoven
layer may be integral with at least a portion of the chassis 22, in
which case the elastomeric element may be attached to the nonwoven
layer and the non-woven/elastomeric element laminate is
subsequently activated. Alternatively, the nonwoven layer may be a
separate component, in which case the elastomeric element is
attached to the nonwoven layer to form the laminate, which is then
coupled to the main portion. If one or more layers of the side
panel are provided separately, the laminate may be activated either
before or after attachment to the main portion. The zero strain
activation processes is further disclosed in U.S. Pat. Nos.
5,167,897 and 5,156,793. A suitable elastic ear may be an activated
laminate comprising an elastomeric film (such as is available from
Tredegar Corp, Richmond, Va., as supplier code X25007) disposed
between two nonwoven layers (such as is available from BBA
Fiberweb, Brentwood, Tenn. as supplier code FPN332).
[0069] The ears 40, 42 may be discrete or integral. A discrete ear
is formed as separate element which is joined to the chassis 22. An
integral ear is a portion of the chassis 22 that projects laterally
outward from the longitudinal edge 12. The integral ear may be
formed by cutting the chassis form to have the projection.
[0070] A suitable diaper 20 having discrete back ears 42 and
integral front ears 40 is shown in FIG. 1A. A suitable diaper
having discrete back ears 42 and discrete front ears 40 is shown in
FIG. 1B. The front ears 40 may have a proximal edge 41a, a distal
edge 41b, an upper edge 41c, and a lower edge 41d. A portion of the
front ear 40 adjacent to the proximal edge 41a may be joined to the
chassis 22 at a front bond region 45a. The front bond region 45a is
the area within which one or more bonds join the discrete front ear
40 to the chassis 22. The front bond region 45a may comprise one
ore more bonds formed by any bonding method known in the art such
as adhesive bonding, pressure bonding, heat bonding, and the like.
If the front bond region 45a comprises more than one bond, such as
in an array or pattern of bonds, the front bond region 45a is
defined by the are bounded by a polygon connecting the outermost
bonds in each dimension. There may be a degree of overlap between
the front ear 40 and the chassis 12 to allow for bonding. However,
in other embodiments, a larger portion of the front ear 40 may
comprise a layer, element, or substrate of the chassis 22.
[0071] FIG. 1C depicts an embodiment of a diaper 20 having a belt
49 that forms both back ears 42. In this embodiment, no front ears
are present. The belt 49 may extend beyond the opposing
longitudinal edges 12. The back ears 42 may have a proximal edge
43a, a distal edge 43b, an upper edge 43c, and a lower edge 43d.
The proximal edge 43a is taken as projection of the longitudinal
edge 12 on the belt 49.
[0072] As shown in both FIGS. 1A-C, the back ear 42 may be a
discrete element or a portion of a discrete element (e.g., the belt
45) that is joined to the chassis 22. The back ears 42 may have a
proximal edge 43a, a distal edge 43b, an upper edge 43c, and a
lower edge 43d. A portion of the back ear 42 adjacent to the
proximal edge 43a may be joined to the chassis 22 at a back bond
region 45b. The back bond region 45b is the area within which one
or more bonds join the back ear 42 to the chassis 22. The back bond
region 45b may comprise one or more bonds formed by any bonding
method known in the art such as adhesive bonding, pressure bonding,
heat bonding, and the like. If the back bond region 45b comprises
more than one bond, such as in an array or pattern of bonds, the
back bond region 45b is defined by the are bounded by a polygon
connecting the outermost bonds in each dimension. There may be a
degree of overlap between the back ear 42 and the chassis 12 to
allow for bonding. However, in other embodiments, a larger portion
or all of the back ear 42 may comprise a layer, element, or
substrate of the chassis 22.
[0073] The diaper 20 may also include a fastening system 50. When
fastened, the fastening system 50 interconnects the front waist
region 36 and the rear waist region 38 resulting in a waist
circumference that may encircle the wearer during wear of the
diaper 20. The fastening system 50 may comprises a fastener such as
tape tabs, hook and loop fastening components, interlocking
fasteners such as tabs & slots, buckles, buttons, snaps, and/or
hermaphroditic fastening components, although any other known
fastening means are generally acceptable. Some exemplary surface
fastening systems are disclosed in U.S. Pat. Nos. 3,848,594;
4,662,875; 4,846,815; 4,894,060; 4,946,527; 5,151,092; and
5,221,274. An exemplary interlocking fastening system is disclosed
in U.S. Pat. No. 6,432,098. The fastening system 50 may also
provide a means for holding the article in a disposal configuration
as disclosed in U.S. Pat. No. 4,963,140. The fastening system 50
may also include primary and secondary fastening systems, as
disclosed in U.S. Pat. No. 4,699,622. The fastening system 50 may
be constructed to reduce shifting of overlapped portions or to
improve fit as disclosed in U.S. Pat. Nos. 5,242,436; 5,499,978;
5,507,736; and 5,591,152.
[0074] FIG. 1A depicts a fastening system 50 having an engaging
member 52 proximate the distal edge 43b of the back ear 42 and a
receiving member 54 disposed in the front waist region 36 of the
chassis 22. The engaging member 52 is shown having an engaging
surface 53 that may comprise hooks, loops, an adhesive, a cohesive,
or other fastening member. FIG. 1A depicts the engaging surface 53
as covering only a portion of the engaging member 52; however, in
other embodiments, the engaging surface 53 may cover substantially
all of one or more faces of the engaging member 52. The engaging
member 52 may be joined to the back ear 42 at a fastener bond
region 47. The fastener bond region 47 is the area within which one
or more bonds join the engaging member 52 to the back ear 42. The
fastener bond region 47 may comprise one or more bonds formed by
any bonding method known in the art such as adhesive bonding,
pressure bonding, heat bonding, and the like. If the fastener bond
region 47 comprises more than one bond, such as in an array or
pattern of bonds, the fastener bond region 47 is defined by the are
bounded by a polygon connecting the outermost bonds in each
dimension. In certain cases, such as shown in FIG. 1B, the fastener
bonding region 47 may be a line of attachment.
[0075] The receiving member 54 may have a receiving surface 55 (as
shown in FIGS. 1A and 1C) that allows for engagement of the
engaging member 52. The receiving surface 54 may comprise hooks,
loops, an adhesive, a cohesive, or other fastening component that
can receive the engaging member 52. Suitable engaging member 52 and
receiving member 54 combinations include but are not limited to
hooks/loop, hooks/hooks, adhesive/polymeric film;
cohesive/cohesive, adhesive/adhesive; tab/slot; and button/button
hole.
[0076] FIG. 2A is a perspective view of the diaper 20 of FIG. 1A in
a fastened configuration as would be seen during normal wear of the
diaper. The engaging surface 53 of the engaging member 52 may be
mated with the receiving member 54. The back ear 42 may span and
connect the front waist region 36 and the rear waist region 38 to
form a leg opening 86 defined by a leg edge 88 (which includes a
portion of the longitudinal edge 12 and the lower edge 44d of the
back ear 42) and a waist opening 80 defined by a waist edge 82
(which includes a portion of the lateral edges 14 of the chassis 22
and the upper edge 44c of the back ear 42). In embodiments where
the back ear 42 is extensible or elastic, the back ear 42 may be
extended to provide a tensioning force to the diaper 20 during
wear.
[0077] FIG. 1B depicts a diaper 20 having front and back ears 40,
42. The diaper may have a fastening system 50 comprising an
engaging member 52 and a receiving member 54. The engaging member
52 may be disposed proximate the distal edge 43b of the back ear
42. The receiving member 54 may be disposed proximate the distal
edge 41b of the front ear. In the FIG. 1B, the engaging member 52
is depicted as a tab member 56 and the receiving member 54 is
depicted as a slot member 58 with a slot 59 therethrough. In a
simple form, the fastening system 50 may be fastened by passing the
tab member 56 completely through the slot 59 of the slot member 58.
Once the tab member 56 has been passed through the slot member 58,
the tab member 56 may be rotated into a plane generally parallel
with the plane of the slot member 58 such that at least a part of
the tab member 56 overlaps at least a portion of the slot member
58. FIG. 2B is a perspective view of the diaper 20 of FIG. 1B in a
fastened configuration as would be seen during normal wear of the
diaper 20. The tab member 56 and the slot member 58 are joined to
form a leg opening 86 defined by a leg edge 88 (which includes a
portion of the longitudinal edge 12, the lower edge 41d of the
front ear 40, and the lower edge 43d of the back ear 42) and a
waist opening 80 defined by a waist edge 82 (which includes a
portion of the lateral edges 14 of the chassis 22, the upper edge
41c of the front ear, and the upper edge 43c of the back ear 42).
In embodiments where the front ear 40 or the back ear 42 is
extensible or elastic, the ear 40, 42 may be extended to provide a
tensioning force to the diaper 20 during wear. It should be
recognized that other suitable engaging member 52 and receiving
member 54 combinations may be used instead or in addition to the
tab and slot.
[0078] FIGS. 1A-C and 2A-B include a front tophat 99a and/or a back
tophat 99b. In FIG. 1A, the back tophat 99b is shown in the rear
waist region 38 as the portion of the diaper 20 bounded by the
upper edge 43c of the back ear 42 and the lateral edge 14 in the
rear waist region 38. Once fastened, as shown in FIG. 2A, the
diaper 20 may have a front tophat 99a in the front waist region 36.
The front tophat 99a is the portion of the diaper 20 bounded by the
upper edge 41c of the back ear 42 and the lateral edge 14 in the
front waist region 36.
[0079] In FIGS. 1B and 2B, the front tophat 99a is shown in the
front waist region 36 as the portion of the diaper 20 bounded by
the upper edge 41c of the front ear 40 and the lateral edge 14 in
the front waist region 36. The back tophat 99b is shown in the rear
waist region 38 as the portion of the diaper 20 bounded by the
upper edge 43c of the back ear 42 and the lateral edge 14 in the
rear waist region 38.
[0080] In FIG. 1C, the back tophat 99b is shown in the rear waist
region 38 as the portion of the diaper 20 bounded by the upper edge
43c of the back ear 42 and the lateral edge 14 in the rear waist
region 38.
[0081] FIG. 3A is a magnified planar, side view of the diaper 20 of
FIG. 2A showing the back ear 42, a portion of the front waist
region 36, and a portion of the rear waist region 38. FIG. 3B is a
magnified planar, side view of the diaper 20 of FIG. 2B showing the
back ear 42, the front ear 40, a portion of the front waist region
36, and a portion of the rear waist region 38. To more precisely
and quantitatively describe the tophats 99a and 99b, a number of
metrics are shown. Suitable metrics include a Front Edge
Displacement A, a Rear Edge Displacement C, an Ear Span Width B, an
Ear Midpoint Width X, and a Receiving Member Midpoint Width Y.
Several of the metrics are determined with reference to a first
product mark 1, a second product mark 2, and a lateral reference
line 3. The receiving member 54 may include a longitudinal midpoint
48a. The engaging member may include a longitudinal midpoint 48b.
The method for measuring the metrics and applying the product marks
1 and 2, the lateral reference line 3, the midpoints 48a, 48b to
the diaper 20 is discussed below in the Metric Test Method
section.
[0082] To address the problem of tophatting, it is desirable that
the Front Edge Displacement A and the Rear Edge Displacement C be
reduced or eliminated. In certain embodiments, the Front Edge
Displacement A may be no greater than about 1.0 mm. Alternatively,
the Front Edge Displacement A may be no greater than about 0.5 mm
or about 0.3 mm. In certain embodiments, the Front Edge
Displacement A may be about 0. In certain embodiments, the Rear
Edge Displacement C may be no greater than about 10 mm.
Alternatively, the Rear Edge Displacement C may be no greater than
about 7 mm, about 5 mm, about 3 mm, or about 1 mm. In certain
embodiments, the Rear Edge Displacement C may be about 0. Any
combination of the aforementioned Front Edge Displacement A and
Rear Edge Displacement C is also within the scope of the invention.
Furthermore, in certain embodiments, the sum of the Front Edge
Displacement A and the Rear Edge Displacement C may be no greater
than about 12 mm. Alternatively, the sum of the Front Edge
Displacement A and the Rear Edge Displacement C may be no greater
than about 10 mm, about 5 mm, about 3 mm, or about 1 mm. In certain
embodiments, the sum of the Front Edge Displacement A and the Rear
Edge Displacement C may be about 0.
[0083] In other embodiments, it has been found that a ratio of the
Front Edge Displacement A or Rear Edge Displacement C to the Ear
Span Width B is very important in consumer perception of tophatting
and the resulting waist edge discontinuity. For example, the waist
edge discontinuity may be less appreciable in a diaper with a
larger Ear Span Width B rather than with a diaper having a smaller
Ear Span Width B. In certain embodiments, the ratio of the Front
Edge Displacement A to the Ear Span Width B (A/B) may be no greater
than about 0.05. In certain embodiments, the ratio of the Front
Edge Displacement A to the Ear Span Width B (A/B) is about 0. In
certain embodiments, the ratio of the Rear Edge Displacement C to
the Ear Span Width B (C/B) may be no greater than about 0.24.
Alternatively, the ratio of the Rear Edge Displacement C to the Ear
Span Width B (C/B) may be no greater than about 0.20 or about 0.10.
In certain embodiments, the ratio of the Rear Edge Displacement C
to the Ear Span Width B (C/B) is about 0.
[0084] In other embodiments, it may be desirable that the combined
Front Edge Displacement A and the Rear Edge Displacement C be
minimized in relation to the Ear Span Width B. The sum of Front
Edge Displacement A and the Rear Edge Displacement C to the Ear
Span Width B ratio ((A+C)/B) may be no greater than about 0.30.
Alternatively, the combined Front Edge Displacement A and the Rear
Edge Displacement C to the Ear Span Width B ratio ((A+C)/B) may be
less than about 0.20 or about 0.10. In other embodiments, the
combined Front Edge Displacement A and the Rear Edge Displacement C
to the Ear Span Width B ratio ((A+C)/B) is about 0.
[0085] In other embodiments, it has been found that a ratio of the
Front Edge Displacement A to the Ear Midpoint Width X is very
important in consumer perception of tophatting and the resulting
waist edge discontinuity. For example, the waist edge discontinuity
may be less appreciable in a diaper with a larger Ear Midpoint
Width X rather than with a diaper having a smaller Ear Midpoint
Width X. In certain embodiments, the ratio of the combined Front
Edge Displacement A and the Rear Edge Displacement C to the Ear
Midpoint Width X ((A+C)/X) may be less than about 0.30.
Alternatively, the ratio of the combined Front Edge Displacement A
and the Rear Edge Displacement C to the Ear Midpoint Width X
((A+C)/X) may be about 0.25, about 0.20, or about 0.10. In other
embodiments, the ratio of the combined Front Edge Displacement A
and the Rear Edge Displacement C to the Ear Midpoint Width X
((A+C)/X) is about 0.
[0086] FIGS. 1-3 depict the back ear 42 being bonded to and
extending from the rear waist region 38 and designed such that the
engaging member 52 joined to the back ear 42 may engage the
receiving member 54 disposed in the front waist region 36. However,
it should be readily apparent to one skilled in the art that the
back ear may be configured to be a front ear 42 which may be bonded
to and extend from the front waist region 36 and designed such that
the engaging member 52 joined to the front ear may engage the
receiving member 54 disposed in the rear waist region 38. The Front
Edge Displacement A, Rear Edge Displacement C, Ear Span Width B,
Ear Midpoint Width X, and the Receiving Member Midpoint Width Y are
equally applicable to a front ear.
Metric Test Method
[0087] This method describes a method to mark and capture physical
reference points on diapers as they are pulled to known tensile
force values with a calibrated programmable mechanical tensile
tester. This method also describes the process for making the
appropriate distance calculations using spreadsheet software such
as Microsoft Excel. These calculations are based upon measurements
of pixel x-y coordinates taken from digital camera images through
the use of photo-analysis computer program.
[0088] A suitable tensile tester must be capable of pulling at a
constant crosshead rate of 127 mm/min. The tensile tester must be
equipped with a calibrated load cell such that the tested load
values are no less than 1% of the calibration ranged of the load
cell. A suitable tensile tester is a MTS Tensile Tester, Model 1/S
available from MTS Systems Corp., Eden Prairie, Minn. and loaded
with a 10N load cell. The tensile tester includes two matching
grips 410a and 410b as shown in FIG. 4. Each grips 410a, 410b
includes a semi-cylindrical face 412 upon which a sample may be
mounted. The faces 412 are made from 1.50 mm thick stainless having
a length L of 127 mm. The faces 412 have a diameter D of 115 mm.
Each face 412 is joined to a hook 414 that allow the grip 410 to be
joined to the tensile tested. The hook 414 runs the length L of the
inside surface of the semi-cylindrical face. One grip 410a is
joined to the load cell and movable crosshead of the tensile
tester. The other grip 410b is joined to the non-moving base of the
tensile tester.
[0089] All values reported below are an average of five random
samples. To ensure the randomization of consumer commercial
samples, the five samples are to be taken as follows: [0090] (i) If
the consumer commercial sample is sold individually (i.e., one
sample may be individually purchased), then five consumer
commercial samples are acquired. [0091] (ii) If the consumer
commercial sample is to be sold as a plurality (i.e., several
samples are purchased as a single unit), then five pluralities are
to be acquired. One sample from each of the five pluralities is
randomly chosen for testing.
[0092] Product Marks:
[0093] Two product marks "+" are to be placed on the left side
(i.e., the side of the product that would fall along the left side
of a wearer during normal wear of the sample) of each sample prior
to testing. The product marks may be made using a fine tip
permanent marker or like device. The first product mark 1, as shown
in FIGS. 3A-B, is made according to the following steps: [0094] 1.
If the product has a fastener bonding zone 47 (as shown in FIG.
3A-B), the first product mark is placed in the center of the
fastener bonding zone 47. [0095] 2. If the product has no fastener
bonding zone 47, the first product mark is placed in the center of
the engaging surface 53. [0096] 3. If 1 or 2 are not available, the
first product mark is placed in the center of the engaging member
52. The second product mark 2, as shown in FIGS. 3A-B, is placed in
the center of the back bond region 45b. A lateral reference line 3
is drawn through the first product mark 1 and the second product
mark 2; the line 3 terminates at the inboard and outboard edge of
the ear/engaging member combination.
[0097] Metric Measurement:
[0098] The Front Edge Displacement A, Rear Edge Displacement C, Ear
Span Width B, Ear Midpoint Width X, and the Receiving Member
Midpoint Width Y may be determined according to the description
provided below and with reference to FIGS. 3A-B. For purposes of
metric measurement and procedural steps, when measuring to or from
an edge, the term "edge" means in order of preference: [0099] 1. A
physical edge 510 of a sample 500 if said edge 510 is linear and
intersects with a line segment 512 to be drawn, as shown in FIG.
5A. [0100] 2. If not 1, then a linear projection 514 from the
physical edge 510 of the sample 500 if the physical edge 510 is
substantially linear, as shown in FIG. 5B. [0101] 3. If not 1 or 2,
then a tangential line 516 drawn from the outermost point 518 on
the physical edge 510 of the sample 500, as shown in FIG. 5C.
[0102] FIGS. 5A-C are provided to teach how the linear projection
and tangential line should be drawn on a simple shape (e.g., sample
500). One skilled in the art will be able to apply these teachings
to drawing the linear projection and tangential line on the various
edges of an absorbent article.
[0103] The Front Edge Displacement A is the distance of a line
segment drawn from (i) the intersection of the upper edge of the
ear and the front longitudinal edge 12a and perpendicular to (ii)
the lateral edge 14 in the front waist region 36, a linear
projection of the lateral edge 14 in the front waist region 36, or,
for samples where there is no linear component of the edge, a
tangent line drawn from the edge. As shown in FIG. 3A, the Front
Edge Displacement A is the distance between the upper edge 43c of
the back ear 42 and the lateral edge 14 of the front waist region
38. As shown in FIG. 3B, the Front Edge Displacement A is the
distance between the upper edge 41c of the front ear 40 and the
lateral edge 14 of the front waist region 38.
[0104] The Rear Edge Displacement C is the distance of a line
segment drawn from (i) the intersection of the upper edge of the
ear and the rear longitudinal edge 12b and perpendicular to (ii)
the lateral edge 14 in the rear waist region 38 or a linear
projection of the lateral edge 14 in the rear waist region 38. As
shown in FIGS. 3A and 3B, the Rear Edge Displacement C is the
distance between the upper edge 44c of the back ear 42 and the
longitudinal edge 14 of the rear waist region 38.
[0105] The Ear Span Width B is the linear distance of a line
segment drawn from (i) the intersection of the lower edge of a back
ear with either the front longitudinal edge 12a or an edge of the
front ear 40, whichever is most outboard and (ii) the intersection
of the rear longitudinal edge 12b and a lower edge of a back ear.
As shown in FIG. 3A, the Ear Span Width B is the distance between
(i) the intersection of the front longitudinal edge 12a and the
lower edge 43d of the back ear 42 and (ii) the intersection of the
rear longitudinal edge 12b and the lower edge 43d of the back ear
42. However, for side fastened diapers, such as shown in FIG. 3B,
the Ear Span Width B is the distance of a line segment drawn from
(i) the intersection of the front longitudinal edge 12a and the
lower edge 41d of the front ear 40 and (ii) the intersection of the
rear longitudinal edge 12b and the lower edge 43d of the back ear
42.
[0106] The Ear Midpoint Width X is the distance of the line segment
drawn from (i) the first product mark 1 and perpendicular to (ii)
the lateral edge 14 in the front waist region 36 or a linear
projection of the lateral edge 14 in the front waist region 36.
[0107] The Receiving Member Midpoint Width Y is the distance of the
line segment drawn from (i) a midpoint 48 of the receiving member
54 adjacent the inboard edge of the engaging member 52 (when the
receiving member 54 and the engaging member 52 are in a fastened
configuration) and perpendicular to (ii) the lateral edge 14 in the
front waist region 36 or a linear projection of the lateral edge 14
in the front waist region 36. The longitudinal midpoint 48 of the
receiving member 54 is the midpoint of a line segment drawn
longitudinally from opposing lateral edges of the receiving member
54. In some instances such as shown in FIG. 3B, the receiving
member 54 may be overlapped by the engaging member 52. In such
instances, the midpoint 48 of the receiving member 54 is the
midpoint of a line segment drawn longitudinally from the linear
projection of the opposing lateral edges of the receiving member 54
and drawn adjacent to the inboard edge of the engaging member
52.
[0108] Procedural Steps:
[0109] The metrics are measured according to the steps that follow:
[0110] 1. A calibration ruler is placed in proximity to the grips.
The calibration ruler marked in millimeters is mounted so the
ruled-face of the ruler is on the same plane as the surface of the
product being measured. [0111] 2. A digital camera is mounted on a
tripod adjacent to the tensile tester and positioned in such a way
that the sample and calibration ruler fill the camera's field of
view as much as possible. The camera is aligned vertically and
horizontally with the surface of the sample. [0112] 3. The sample
is marked with the two product marks and the lateral reference line
as described above. [0113] 4. The sample is fastened to the
sample's largest possible fastener setting. The engaging member
should be joined to the receiving member such that a longitudinal
midpoint of the engaging member is aligned longitudinally, at the
point of intersection, with a longitudinal midpoint of the
receiving member. The longitudinal midpoint of the receiving member
is the midpoint of a line segment drawn longitudinally from
opposing lateral edges of the receiving member. The longitudinal
midpoint of the engaging member is the midpoint of a line segment
drawn longitudinally from opposing lateral edges of the engaging
member. Additionally, the proximal edge of the engaging surface
should be aligned with the longitudinal edge of the receiving
surface. In samples not having a distinct engaging surface or
receiving surface, the engaging member and receiving member of the
sample should be fastened such that (i) the lateral edges in the
front and back waist regions are aligned and (ii) the distal edge
of the engaging member is placed 50 mm inboard of the longitudinal
edge of the front waist region or as far outboard as possible while
still maintaining engagement to the front waist region, whichever
results in the fastener being closer to the longitudinal edge of
the front waist region. [0114] 5. The sample is mounted onto the
grips of the tensile tester such that the front waist region of the
sample is approximately centered on the movable grip and that the
back waist region of the sample is approximately centered on the
stationary grip. The sample is mounted sample so that the sample
marks are facing the camera, all test values are visible, the
sample is at the same distance from the camera as the ruler, and
the sample is perpendicular to the camera's field or view. [0115]
6. The sample is pulled at a constant crosshead rate of 127 mm/min
and held in position for 10 seconds when the load reaches 200
grams. A picture is taken. [0116] 7. The sample is pulled at a
constant crosshead rate of 127 mm/until a load value of 1200 grams
is reached. The crosshead is stopped and a picture is taken. [0117]
8. The crosshead is returned to the original position.
[0118] Using a computer imaging program capable of displaying pixel
values in pictures (i.e., Adobe.RTM. Photoshop.RTM.), each picture
taken at 1200 g load is analyzed. For each picture, a line is drawn
on the digital image for each of the metrics (A, B, C, X, Y, and
W). The pixel coordinates (x and y coordinates) for the end points
of each drawn line are recorded. A line is drawn on the calibration
ruler between two marks that are 50 mm apart. The pixel coordinates
for this line are recorded. The pixel coordinates for endpoints of
each metric and the calibration ruler are entered into an
appropriate computer spreadsheet program (e.g., Microsoft.RTM.
Excel.RTM.). The spreadsheet may be programmed to computer the
distance between endpoints, as measured in pixels, according to the
following equation:
d= {square root over
((x.sub.1.sup.2-x.sub.2.sup.2)+(y.sub.1.sup.2-y.sub.2.sup.2))}{square
root over
((x.sub.1.sup.2-x.sub.2.sup.2)+(y.sub.1.sup.2-y.sub.2.sup.2))}
where d=distance between two points (x.sub.1, y.sub.1) and
(x.sub.2, y.sub.2). The distance in pixels for the calibration
ruler, which is known to be 50 mm, can be use to convert the
distance in pixels of any of the metric measurements into a
distance in millimeters. The spreadsheet is programmed to convert
length values based on pixel coordinates in millimeters.
[0119] The procedural steps are performed for the five duplicate
samples. The distance values for each metric are averaged and the
average is recorded.
Examples
[0120] Example 1 is a suitable example of the present invention.
The chassis of this present example is constructed according to the
description provided for a containment assembly in U.S. Pat. No.
5,151,092. The example has two back ears joined along the opposing
rear longitudinal edges of the chassis. The back ears comprise a
trilaminate with two outmost layers being a nonwoven available from
BBA Nonwovens, Inc., Old Hickory, Tenn. as code HEC FPN 332D.
Disposed between the two nonwoven layers is an elastic film
available from Nordenia USA, Inc., Jackson, Mo. as code KG6361.100.
A portion of the back ear is incrementally stretched according to
the zero strain activation processes disclosed in U.S. Pat. Nos.
5,167,897 and 5,156,793. The back ear further comprises an engaging
member which is a polymer film tab with a hook-bearing surface. The
hook-bearing surface has an approximate area of 3.8 cm.sup.2. The
tab extends from the outboard edge of the back ear opposite the
back ear edge that is joined to the chassis. The example further
comprises a rectilinear receiving member disposed in the front
waist region and on the garment-facing surface of the chassis. The
receiving member is a polymer film patch with fibrous loops on the
garment-facing surface of the patch. The patch is available from
Aplix Fasteners, Inc., Suffolk, UK as code AN29R95327873. The patch
measures approximately 13.5 cm.times.5.0 cm with the long dimension
running approximately parallel to the lateral edge of the
chassis.
[0121] Example 2 is a commercially available comparative sample.
The example is Pampers Cruisers size 4 diaper available from The
Procter & Gamble Company, Cincinnati, Ohio
[0122] Example 3 is a commercially available comparative sample.
The example is Huggies.RTM. Supreme.RTM. size 4 available from the
Kimberly-Clark Corp., Neenah, Wis.
[0123] Example 4 is a commercially available comparative sample.
The example is Baby-Shaped.RTM. Huggies.RTM. size 4 available from
the Kimberly-Clark Corp., Neenah, Wis.
Test Results
TABLE-US-00001 [0124] A B C A + C X Y Example 1 0 (0) 45.2 (5.7)
5.7 (0.7) 5.7 32.5 (1.5) 33.8 (1.1) Example 2 8.7 (2.8) 64.1 (7.7)
15.9 (1.4) 24.6 47.1 (2.4) 46.3 (1.7) Example 3 5.2 (5.0) 49.0
(3.2) 17.8 (3.5) 23.0 40.4 (4.9) 43.8 (3.5) Example 4 4.8 (2.6)
29.2 (2.1) 12.8 (2.5) 17.6 44.1 (1.3) 47.4 (1.6)
All measurements in millimeters. Standard deviation presented in
parenthesis.
TABLE-US-00002 CB (A + C)/B (A + C)/X Example 1 0.13 0.13 0.18
Example 2 0.25 0.38 0.52 Example 3 0.36 0.47 0.57 Example 4 0.44
0.60 0.40
[0125] In one embodiment schematically represented in FIG. 6, an
absorbent article includes an absorbent core 28 that extends
longitudinally between the front waist region 36 and the rear waist
region 38, which is disposed in a front section 128, a middle
section 228 and a back section 328 of the absorbent article. The
absorbent core includes a front edge 428, a back edge 528 and side
edges 628. The front section 128 is the section of the absorbent
article that is generally disposed in the front waist region 36 of
the chassis. The back section 328 is the section of the absorbent
article that is disposed between the lateral back edge of the
chassis and the transverse line A-A connecting the proximal ends of
the lower edge of each of the left and right back ears 42. It
should be noted that the back section 328 does not necessarily
coincide with the rear waist region 38 of the article. The middle
section 228 is the section of the absorbent article that is
generally disposed between and interconnects the front section 128
to the back section 328. In one embodiment, at least part of an
absorbent core is disposed in at least one of the front section
128, the middle section 228 and the back section 328 of the
absorbent article. In one embodiment, an absorbent core is disposed
in the middle section 228 and extends into the at least part of the
front section 128 and/or into the back section 328. In one
embodiment, the part of the absorbent core that is disposed in the
front, middle section, or the back section is substantially
cellulose free. In one embodiment the back section 328 comprises an
absorbent core that is substantially cellulose free. In one
embodiment, at least one of the front section 128, the middle
section 228 and the back section 328 of the absorbent article
comprises an absorbent core and has an average caliper of less than
1.5 mm, less than 1.25 mm, less than 1 mm, less than 0.75 mm or
even less than 0.5 mm. In one embodiment, the back section 328 of
the absorbent article comprises an absorbent core and has an
average caliper of less than 1.5 mm, less than 1.25 mm, less than 1
mm, less than 0.75 mm or even less than 0.5 mm. A suitable method
to measure the average caliper of a section of an absorbent article
is discussed below. Among other benefits, it is believed that an
absorbent article having at least one of, or even all of its front,
middle and back sections that are thin is much more flexible than a
thicker absorbent article while still maintaining its ability to
absorb and retain body exudates. A thin absorbent article can more
easily conform to the wearer's body shape and consequently, is more
underwear-like. In addition, a thin absorbent article provides a
snug fit around the waist and legs of a wearer. An absorbent
article having a thin back section also allows tensions (caused by
the forces created by elastically stretchable ears or side panels
when the article is attached to the wearer) that are applied
transversely on the article backsheet to be closer to the wearer's
skin. Tensions that are applied in close proximity to the wearer's
skin can prevent the article from "sliding" down the wearer's lower
back and buttocks, especially after one or more discharges of body
exudates. But it is also believed that when the front and/or back
sections of the article are thin, these sections may have a
tendency to fold-over when a longitudinal side of these sections is
subjected to lateral forces. It is observed, for instance, that
when a caregiver pulls on a tape tab (such as the one represented
in FIG. 1A) for extending the back ear of the article, at least a
portion of the back section of the article may fold-over inward or
outward. The folding-over of the back section may cause discomfort
to the wearer. Moreover, it may result in an inefficient use of the
absorbent core positioned in the portion that is folded-over and it
may also cause leakage or exudates run-off if a portion of the back
section is folded outward. Without intending to be bound by any
theory, it is believed that this folding-over of the back section
occurs when the outermost line of tension (resulting from an
elongation of the back ear) is located away from the lateral back
edge of the chassis. It is also believed that the distance between
the outermost and innermost lines of tension affects the
folding-over of the back section. One of ordinary skill will
appreciate that a relatively short distance between the outermost
and innermost lines of tension result in a concentration of forces
over a relatively narrow area whereas a longer distance between the
outermost and innermost lines of tension result in a better
distribution of the forces over a larger area. It is also believed
that an "abrupt" change in thickness (in the longitudinal
direction) from the portion of the back section that includes the
absorbent core to the portion of the back section that does not
include the absorbent core may create a weakness or path of least
resistance which is followed by the lines of tension and causes the
back section to fold over. In order to minimize or possibly
eliminate this folding-over, one embodiment of an absorbent article
includes a pair of fastening tabs (i.e. an engaging member) 52 and
52' that are each connected to an elastically elongatable ear 42
(respectively 42'). It will be understood that the fastening tab 52
is the element of the fastening system that includes a fastener 57
and is generally stiffer and less extensible than the elongatable
ear. A fastening tab may be a separate web of material joined to
the ear such as a tape tab as represented in FIG. 1A. The fastener
57 may be at least one of a plurality of hooks protruding away from
the fastening tab, loops, an adhesive, a cohesive, or any other
fastening member suitable to attach the article about the lower
torso of a wearer. A fastening tab can also be integrally formed
with the ear as shown in FIG. 6. For the sake of clarity and
brevity, the description of the left fastening tab and back ear
that follows is applicable to the right fastening tab and back ear
and identical elements are referenced in the drawings with the same
number with the prime symbol (for example, 52 and 52'). The left
back ear 42 is a mirror image of the right back ear 42' and the
left fastening tab 52 is a mirror image of the right fastening tab
52' relative to the absorbent article longitudinal axis. The
fastening tab 52 represented in FIG. 6 includes an upper edge 152
with an upper proximal end 1152 and a lower edge 252 with a lower
proximal end 1252. An elastically elongatable ear 42 includes an
upper edge 142 with upper proximal and distal ends 1142, 2142 and a
lower edge 242 with lower proximal and distal ends 1242, 2242. In
one embodiment, the distance between the upper and lower proximal
ends 1152, 1252 of a fastening tab 52 is at least 20 mm, at least
30 mm or even at least 40 mm. In one embodiment, the distance
between the upper and lower proximal ends 1152, 1252 of a fastening
tab 52 is between 20 mm and 80 mm, between 30 mm and 70 mm or even
between 40 mm and 60 mm. In one embodiment, the back ears 42 and
42' are connected to the chassis such that the transversal line
(represented in FIG. 6 by line B-B) that includes the upper end
1152 of the left fastening tab 52 and the upper end 1152' of the
right fastening tab 52' is positioned between the back lateral edge
14 of the chassis and the back edge 528 of the absorbent core. In
one embodiment, the longitudinal distance between the transversal
line (B-B) previously described and the back edge 14 of the chassis
is less than 25 mm, less than 20 mm, less than 15 mm or even less
than 10 mm. In one embodiment, the back ears 42, 42' are connected
to the chassis such that the back edge 528 of the absorbent core is
positioned between the transversal line B-B and the transversal
line (represented in FIG. 6 by line C-C) that includes the lower
end 1252 of the left fastening tab 52 and the lower end 1252' of
the right fastening tab 52'. In one embodiment, the distance
between the upper distal end 2142 and the lower distal end 2242 of
the elongatable back ear 42 is greater than the distance between
the upper and lower proximal ends 1152, 1252 of a fastening tab 52.
In one embodiment, the distance between the upper and lower distal
ends 2142, 2242 of the elongatable back ear 42 is the same as the
distance between the upper and lower proximal ends 1152, 1252 of a
fastening tab 52. Among other benefits, it is believed that when
the distance between the upper and lower distal ends 2142, 2242 of
the elongatable back ear 42 is the same as the distance between the
upper and lower proximal ends 1152, 1252 of a fastening tab 52, the
lateral forces that are applied on the fastening tab 52 are better
distributed across the ear 42 and maximizes usage of the ear
material. In one embodiment, the distance between the upper and
lower proximal ends 1142, 1242 of the back ear 42 is the same as
the distance between the upper and lower distal ends 2142, 2242 of
the back ear 42. In one embodiment illustrated in FIG. 6, the
distance between the upper and lower proximal ends 1142, 1242 is
greater than the distance between the upper and lower distal ends
2142, 2242. Among other benefits, it is believed that ears that are
cut and sized such that the distance between the upper and lower
proximal ends 1142, 1242 is greater than the distance between the
upper and lower distal ends 2142, 2242 provide a more sustained fit
around the wearer's legs and hips. In one embodiment, the distance
between the upper and lower proximal ends 1142, 1242 of the back
ear 42 is at least 5%, at least 10% at least 25% or even at least
50% greater than the distance between the upper and lower distal
ends 2142, 2242 of the back ear 42. In one embodiment, the upper
edge 152 of the fastening tab 52 is asymmetric to the lower edge
252 of the fastening tab relative to the transverse axis Tf of the
fastening tab 52. The transverse axis Tf of the fastening tab 52 is
the line that is equidistant from the upper and lower proximal ends
1152, 1252 of the fastening tab and is perpendicular to the line
that includes the upper and lower proximal ends 1152, 1252 of the
fastening tab. In one embodiment, the upper edge 142 of the
elongatable back ear 42 is asymmetric to the lower edge 242 of the
elongatable back ear relative to the transverse axis Te of the
elongatable back ear. The transverse axis Te of the elongatable
back ear 42 is the line that is equidistant from the upper and
lower proximal ends 1142, 1242 of the back ear and is perpendicular
to the line that includes the upper and lower proximal ends 1142,
1242 of the back ear 42. In one embodiment, the transverse axis Tf
of the fastening tab 52 overlaps substantially with the transverse
axis Te of the elongatable ear 42. In one embodiment, the
transverse axis Tf of the fastening tab 52 is offset relative to
the transverse axis Te of the elongatable ear 42. The transverse
axis Tf of the fastening tab 52 and the transverse axis Te of the
elongatable ear 42 can be separated by a distance of at least 5 mm,
at least 10 mm, at least 15 mm or even at least 20 mm. In one
embodiment, the back ears 42, 42' are connected to the chassis such
that the lateral back edge 528 of the absorbent core 28 is
positioned between the lateral back edge 14 of the chassis and the
transverse axis Te of an elongatable back ear 42. In one
embodiment, the back ears 42 and 42' are connected to the chassis
such that the longitudinal distance between the transverse axis Te
of the elongatable back ear 42 and the back edge 528 of the
absorbent core is less than 50 mm, less than 40 mm, less than 30 mm
or even less than 20 mm. In one embodiment, the longitudinal
distance between the transverse axis Te of the elongatable back ear
42 and the back edge 528 of the absorbent core is between 0 mm and
50 mm, between 5 mm and 40 mm or even between 10 mm and 30 mm. In
one embodiment, the back ears 42, 42' are connected to the chassis
such that the transverse Tf axis of a fastening tab 52 is
positioned between the back edge 14 of the chassis and the back
edge 528 of the absorbent core 28. In one embodiment, the back ears
42, 42' are connected to the chassis such that the longitudinal
distance between the transverse axis Tf of the fastening tab and
the back edge 528 of the absorbent core is less than 50 mm, less
than 40 mm, less than 30 mm or even less than 15 mm. In one
embodiment, the longitudinal distance between the transverse axis
Tf of the fastening tab 52 and the back edge 528 of the absorbent
core is between 0 mm and 30 mm, between 2 mm and 20 mm or even
between 2 mm and 15 mm. A magnified view of an elongatable ear 42
and fastening tab 52 is represented in FIG. 7 for clarity and also
to illustrate that the ear 42 and fastening tab 52 may have a shape
other than the shape represented in FIG. 6.
[0126] In one embodiment, the portion of the back section 328 of
the chassis that is positioned between the back lateral edge 14 of
the chassis and the back edge 528 of the absorbent core has an
average caliper of less than 1 mm, less than 0.75 mm, less than 0.5
mm, or even less than 0.25 mm. In one embodiment, the longitudinal
distance between the lateral back edge 14 of the chassis and the
back edge 528 of the absorbent core is less than 100 mm, less than
90 mm or even less than 80 mm. In one embodiment, the longitudinal
distance between the back lateral edge 14 of the chassis and the
back edge 528 of the absorbent core is at least 10 mm, at least 15
mm or even at least 20 mm. In one embodiment, the back section of
the absorbent article has an Average Caliper Differential of less
than 1.25 mm, less than 1 mm, less than 0.75 mm or even less than
0.5 mm. In one embodiment, the back section of the absorbent
article has an Average Caliper Differential of between 0.1 mm and
1.25 mm, between 0.1 mm and 1 mm, between 0.1 mm and 0.5 mm or even
between 0.1 mm and 0.25 mm. The Average Caliper Differential of a
section of the an absorbent article can be determined by measuring
the average caliper of the portion of the back section of the
chassis positioned between the back lateral edge of the chassis and
the back edge of the absorbent core and the average caliper of the
back section of the chassis that comprises an absorbent core. The
average caliper of the portion of the back section of the chassis
positioned between the back lateral edge of the chassis and the
back edge of the absorbent core is then deducted from the average
caliper of the back section of the chassis that comprises an
absorbent core. Without intending to be bound by any theory, it is
believed that a back section of an absorbent article having such an
Average Caliper Differential is less likely to fold-over along the
edge of the absorbent core.
Caliper Test
[0127] Equipment:
[0128] Caliper Instrument: Ono Sokki digital caliper gauge DG-3610
connected to an Ono Sokki linear gauge sensor GS-503
[0129] Contact Foot: Flat circular foot with a diameter of 40 mm
(+/-0.5 mm)
[0130] Weigh/Pressure: Total weight of foot and shaft equals 80+/-2
g to equal approximately 0.1 PSI applied to the sample. A circular
weight may be applied to the foot (i.e., a weight with a slot to
facilitate application around the shaft) to achieve the target
weight.
[0131] Ruler--Calibrated metal ruler graduated in mm.
[0132] Stopwatch--Accuracy 1 second
[0133] Sample Preparation:
[0134] 1. If the absorbent articles are in their original, unopened
package, the sample articles to be tested are removed from the
center area of the package. If the package contains more than 4
products, the outer most two articles on each side of the package
are not used in the testing.
[0135] 2. If the absorbent article has been out of its original
package for more than 15 minutes, place it under an even pressure
of 0.345 N/cm2 (0.5 lb/in2) for 30 minutes.
[0136] 3. Physical manipulation of product should be minimal and
restricted only to necessary sample preparation.
[0137] 4. As the diapers relax (i.e. expand) when removed from the
compressed condition, the time between removal from the package and
the actual caliper testing may be impact the measurement.
Consequently, caliper readings should be taken approximately 5 to
15 minutes after the product is removed from the package or from
under the applied pressure (as previously described).
[0138] 5. Cut or remove any elastic components of the article that
prevent the article from being laid flat under the caliper foot.
These may include leg cuffs or waistbands. Avoid touching absorbent
core area and do not compress the absorbent core area with the
hands
[0139] 6. Mark the measuring point(s) gently on the diaper with a
permanent felt tip marker.
[0140] Caliper Measurement Location:
[0141] a) Lay article flat on a counter top,
[0142] b) Measure the uncontracted length of the article between
the front and back edges along the longitudinal axis of the
article. Record this measurement.
[0143] c) Divide the length by eight.
[0144] d) Very gently mark a lateral measurement line across the
back portion of the article at a distance of one-eight the article
length from the back waist edge of the article, using a permanent
felt tip marker.
[0145] e) Very gently mark a line along the longitudinal axis of
the article in the back portion of the article using a permanent
felt tip marker.
[0146] f) At a distance of 20 mm laterally outboard of each side of
the line indicating the longitudinal axis, very gently mark a 40 mm
longitudinal measurement line parallel with the longitudinal axis
and bisected by the lateral measurement line.
[0147] g) The intersections of the lateral measurement line and the
two longitudinal measurement lines represent the locations where
the center of the caliper foot will contact during the caliper
measurement. These intersections are referred to as the "marked
measuring points".
Caliper Measurement Steps:
[0148] 1. Raise the caliper gauge contact foot and place the
article on the caliper gauge base plate, garment-facing surface
side down.
[0149] 2. With the foot raised, position the article on the base
plate in a manner that when lowered, the center of the foot is on
one of the marked measuring points.
[0150] 3. Gently lower the foot onto the diaper
[0151] 4. Read the caliper value to the nearest 0.01 mm, 5 seconds
after the foot comes in contact with the diaper. Record the caliper
measurement.
[0152] 5. Reset the instrument reading to zero after each
measurement.
[0153] 6. Repeat steps 1 through 5 for the second marked measuring
point.
[0154] Caliper Calculations:
[0155] For each article, average the two caliper measurements to
calculate the rear waist region caliper for that article.
Generally, at least five samples are measured in this manner for a
given product and the rear waist region calipers may be aggregated
to calculate an average and standard deviation.
Absorbent Core.
[0156] In one embodiment, an absorbent article includes an
absorbent core 28 that is substantially cellulose free.
Cross-sectional views of examples of suitable absorbent cores are
schematically represented in FIGS. 8-10. The absorbent core 28 is
the element of the absorbent article whose primary function is to
absorb and retain liquid body exudates. Additional elements may be
added between the topsheet and the absorbent core of an absorbent
article to facilitate the acquisition and the distribution of body
exudates. Such elements may include, for example, an acquisition
layer and/or a distribution layer as it is well known in the art.
The acquisition and/or distribution layers may themselves be
substantially cellulose free (for example made entirely of a
nonwoven material) or include a significant amount of cellulosic
material. Although an absorbent core generally includes absorbent
materials in particulate form having a high retention capacity such
as, for example absorbent polymers, these materials do not need to
be present along the entire length of the absorbent core. It may be
advantageous to provide an absorbent core with a greater amount of
absorbent material in the crotch area and/or the front waist region
in comparison to the back waist region which may include only a
little amount, if any, of absorbent polymers. In one embodiment, an
absorbent core 28 comprises first and second layers of material
281, 282 and an absorbent material 283 disposed between the first
and second layers 281, 282. In one embodiment the first and second
layers of material can be a fibrous material chosen from at least
one of a nonwoven fibrous web, a woven fibrous web and a layer of
thermoplastic adhesive material. Although the first and second
layers can be made of a same material, in one embodiment, the first
layer 281 is a nonwoven fibrous web and the second layer 282 is a
layer of thermoplastic adhesive material. A nonwoven fibrous web
281 can include synthetic fibers, such as mono-constituent fibers
of PE, PET and PP, multi-constituent fibers such as side by side,
core/sheath or island in the sea type fibers. Such synthetic fibers
may be formed via a spunbonding process or a meltblowing process.
The nonwoven fibrous web 281 may include a single layer of fibers
but it may also be advantageous to provide the nonwoven web with
multiple layers of fibers such as multiple layers of spunbond
fibers, multiple layers of meltblown fibers or combinations of
individual layer(s) of spunbond and meltblow fibers. In one
embodiment, the nonwoven web 281 can be treated with an agent (such
as a surfactant) to increase the surface energy of the fibers of
the web. Such an agent renders the nonwoven web more permeable to
liquids such as urine. In another embodiment, the nonwoven web can
be treated with an agent (such as a silicone) that lowers the
surface energy of the fibers of the nonwoven web. Such an agent
renders the nonwoven web less permeable to liquids such as
urine.
[0157] The first layer 281 comprises a first surface 2811 and a
second surface 2812 and at least regions 2813 of the first surface
are in direct facial relationship with a significant amount of
absorbent material 283. In one embodiment an absorbent material is
deposited on the first surface 2811 in a pattern to form regions
2813 on the first layer 281, which are in direct facial
relationship with a significant amount of absorbent polymer
material 283 and regions 2814 on the first web that are in facial
relationship with only an insignificant amount of absorbent
material. By "direct facial relationship with a significant amount
of absorbent material" it is meant that some absorbent material is
deposited on top of the regions 2813 at a basis weight of at least
100 g/m.sup.2, at least 250 g/m.sup.2 or even at least 500
g/m.sup.2. The pattern may include regions that all have the same
shape and dimensions (i.e. projected surface area and/or height).
In the alternative the pattern may include regions that have
different shape or dimensions to form a gradient of regions. At
least some of the regions 2813 can have a projected surface area of
between 1 cm.sup.2 and 150 cm.sup.2 or even between 5 cm.sup.2 and
100 cm.sup.2. By "facial relationship with an insignificant amount
of absorbent material" it is meant that some absorbent material may
be deposited on top of the regions 2814 at a basis weight of less
than 100 g/m.sup.2, less than 50 g/m.sup.2 or even substantially no
absorbent material. At least some of the regions 2814 can have a
projected surface area of between 1 cm.sup.2 and 150 cm.sup.2 or
even between 5 cm.sup.2 and 100 cm.sup.2. The aggregate projected
surface area of all the regions 2813 can represent between 10% and
90% or even between 25% and 75% of the total projected surface area
of the first surface 2811 of the first layer 281. In one
embodiment, the second layer 282 is a layer of a thermoplastic
adhesive material. "Thermoplastic adhesive material" as used herein
is understood to mean a polymer composition from which fibers are
formed and applied to the absorbent material with the intent to
immobilize the absorbent material in both the dry and wet state.
Non-limiting examples of thermoplastic adhesive material may
comprise a single thermoplastic polymer or a blend of thermoplastic
polymers. The thermoplastic adhesive material may also be a hot
melt adhesive comprising at least one thermoplastic polymer in
combination with other thermoplastic diluents such as tackifying
resins, plasticizers and additives such as antioxidants. In certain
embodiments, the thermoplastic polymer has typically a molecular
weight (Mw) of more than 10,000 and a glass transition temperature
(Tg) usually below room temperature or -6.degree.
C.>Tg<16.degree. C. In certain embodiments, typical
concentrations of the polymer in a hot melt are in the range of
about 20 to about 40% by weight. Exemplary polymers are (styrenic)
block copolymers including A-B-A triblock structures, A-B diblock
structures and (A-B)n radial block copolymer structures wherein the
A blocks are non-elastomeric polymer blocks, typically comprising
polystyrene, and the B blocks are unsaturated conjugated diene or
(partly) hydrogenated versions of such. The B block is typically
isoprene, butadiene, ethylene/butylene (hydrogenated butadiene),
ethylene/propylene (hydrogenated isoprene), and mixtures thereof.
Other suitable thermoplastic polymers that may be employed are
metallocene polyolefins, which are polymers prepared using
single-site or metallocene catalysts. In exemplary embodiments, the
tackifying resin has typically a Mw below 5,000 and a Tg usually
above room temperature, typical concentrations of the resin in a
hot melt are in the range of about 30 to about 60% by weight, and
the plasticizer has a low Mw of typically less than 1,000 and a Tg
below room temperature, with a typical concentration of about 0 to
about 15%.
[0158] The thermoplastic adhesive material 282 can be disposed
substantially uniformly within the absorbent material 283. In the
alternative and as represented in FIG. 8, the thermoplastic
adhesive material 282 can be provided as a fibrous layer disposed
on top of the absorbent material 283 and the regions 2814 of the
first surface 2811 that are in facial relationship with only an
insignificant amount of absorbent material. In one embodiment, a
thermoplastic adhesive material is applied at an amount of between
1 and 20 g/m.sup.2, between 1 and 15 g/m.sup.2 or even between 2
and 8 g/m.sup.2. The discontinuous deposition of absorbent material
on the first layer 281 imparts an essentially three-dimensional
structure to the fibrous layer of thermoplastic material 282. In
other words, the layer of thermoplastic adhesive material follows
the topography resulting from the absorbent material 283 deposited
on the first nonwoven fibrous web 281 and the regions 2814 that
only include insignificant amounts of absorbent material. Without
intending to be bound by any theory, it is believed that the
thermoplastic adhesive materials disclosed herein enhance
immobilization of the absorbent material in a dry and wet
state.
[0159] In one embodiment, the absorbent core 28 may further
comprise a second layer of a nonwoven fibrous material 284 as
represented in FIG. 9. This second layer may be provided of the
same material as the nonwoven fibrous layer 281, or in the
alternative may be provided from a different material. It may be
advantageous for the first and second nonwoven fibrous layers 281,
284 to be different in order to provide these layers with different
functionalities. In one embodiment, the surface energy of the first
nonwoven layer can be different than the surface energy of the
second nonwoven layer. In one embodiment, the surface energy of the
second nonwoven layer is greater than the surface energy of the
first nonwoven layer. Among over benefits, it is believed that when
the surface energy of the second nonwoven layer is greater than the
surface energy of the first nonwoven layer, liquids such as urine
will be able to penetrate the second nonwoven layer more easily in
order to reach and be retained by the absorbent material while at
the same time reducing the chances that the liquid may penetrate
and go through the first layer. This may be particularly
advantageous when the first nonwoven layer is disposed against the
backsheet of an absorbent article. The different surface energies
of each layer may be obtained, for example, by applying a different
amount of an agent such as a surfactant to the second nonwoven
layer than the amount of surfactant (if any) applied to the first
nonwoven layer. This may also be achieved by applying a different
type of surfactant to the second nonwoven layer than the surfactant
applied to the first nonwoven layer. This may still be achieved by
applying a material to the first nonwoven layer that lowers its
surface energy. In addition to having different surface energies,
or in the alternative, the first and second nonwoven fibrous layers
281, 284 may also be different structurally. In one embodiment, the
first nonwoven layer 281 may include different layers of fibers
than the second nonwoven layer. For example, the second nonwoven
layer 284 may only include one or more layers of spunbond fibers
whereas the first nonwoven layer 281 includes one or more layers of
spundbond fibers and one or more layers of meltblown fibers. In
another embodiment, both nonwoven fibrous layers 281, 284 may
include one or more layers of spunbond fibers and one or more
layers of meltblow fibers but the first and second layers 281, 284
differ in terms of at least one of the chemical composition of the
fibers used to form the nonwoven material, the denier of the fibers
and/or the basis weight of the nonwoven material. In addition to or
in the alternative than the above the first and second nonwoven
layers 281, 284 may also differ in terms of at least one of their
respective hydrohead values, their respective porosity, their
respective Frazier permeability and their respective tensile
properties. The second nonwoven layer 284 may applied directly on
top of the first nonwoven layer 281, the absorbent material 283 and
the thermoplastic adhesive material 282. As a result, the first and
second nonwoven layers 281 and 284 further encapsulate and
immobilize the absorbent material 283.
[0160] The regions 2813 may have any suitable shape in the x-y
dimension (i.e. the horizontal plane) of the absorbent core. In one
embodiment, the regions 2813 form a pattern of disc that are spread
on the first surface of the first web 281. In one embodiment, the
regions 2813 form a pattern of longitudinal "strips" or "bars" that
extend continuously along the longitudinal axis of the absorbent
core (i.e. along the y dimension) and are spread apart from each
other. In one embodiment, the regions 2813 form a pattern of
longitudinal "strips" or "bars" that extend continuously along the
transverse axis of the absorbent core (i.e. along the x dimension).
In an alternative embodiment, these strips may be are arranged to
form an angle of at between 10 and 90 degrees, between 20 and 80
degrees, between 30 and 60 degrees, or even 45 degrees relative to
the longitudinal axis of the absorbent article. In one embodiment,
a "strip" or "bar" can have a substantially rectangular shape with
the longest side of the rectangle being at least twice, 5 times,
even 25 times, or even 50 times as long as the shortest side of the
rectangle formed by the "strip" or "bar."
[0161] In one embodiment schematically represented in FIG. 10, the
second nonwoven layer 284 has a first surface 2841 and a second
surface 2842 and an absorbent material 283 applied to its first
surface 2841 in order to form a pattern of regions 2843 that are in
direct facial relationship with a significant amount of absorbent
material 283 and regions 2844 on the first surface 2841 that are in
facial relationship with only an insignificant amount of absorbent
material as previously discussed. In one embodiment, a
thermoplastic adhesive material 285 may further be applied on top
of the second nonwoven layer 284 as previously discussed in the
context of the first web/absorbent material/thermoplastic adhesive
material composite. The second nonwoven layer 284 may then be
applied on top of the first nonwoven layer 281. In one embodiment,
the pattern of absorbent material present on the second nonwoven
layer 284 may be the same as the pattern of absorbent material
present on the first nonwoven layer 281. In an other embodiment,
the patterns of absorbent material that are present on the first
and second nonwoven layers are different in terms of at least one
of the shape of the regions, the projected surface areas of the
regions, the amount of absorbent material present on the regions
and the type of absorbent material present on the regions. It is
believed that when the patterns of absorbent material that are
present on the first and second nonwoven layers are different, each
layer/absorbent composite may have different functionalities such
as for example, different absorbent capacities and/or different
acquisition rates of liquids. It can be beneficial for example to
provide an absorbent core with a structure where the second pattern
formed by the regions 2843 of absorbent material (i.e. on the
second nonwoven layer 284) exhibits a slower acquisition rate than
the first pattern of regions 2813 of absorbent material in order to
allow liquids, such as urine, to reach and be absorbed by the
absorbent material deposited on the first nonwoven layer 281 before
expansion of the absorbent material in the regions 2843. Such a
structure avoids any significant gel blocking by the absorbent
material present in the regions 2843. It can also be advantageous
to apply the second layer/absorbent material/thermoplastic adhesive
material composite in such a way that at least some of or even all
of the regions 2813 of the first nonwoven layer 281 that are in
direct facial relationship with a significant amount of absorbent
material are also in substantial facial relationship with
corresponding regions 2844 of the second web 284, which are in
facial relationship with an insignificant amount of absorbent
material.
[0162] The absorbent core 28 may also comprise an auxiliary
adhesive which is not illustrated in the figures. The auxiliary
adhesive may be deposited on at least one of or even both the first
and second nonwoven layers 281, 284 before application of the
absorbent material 283 in order to enhance adhesion of the
absorbent material as well as adhesion of the thermoplastic
adhesive material 282, 285 to the respective nonwoven layers 281,
284. The auxiliary adhesive may also aid in immobilizing the
absorbent material and may comprise the same thermoplastic adhesive
material as described hereinabove or may also comprise other
adhesives including but not limited to sprayable hot melt
adhesives, such as H.B. Fuller Co. (St. Paul, Minn.) Product No.
HL-1620-B. The auxiliary adhesive may be applied to the nonwoven
layers 281, 284 by any suitable means, but according to certain
embodiments, may be applied in about 0.5 to about 1 mm wide slots
spaced about 0.5 to about 2 mm apart. Non-limiting examples of
suitable absorbent material 283 include absorbent polymer material
such as cross linked polymeric materials that can absorb at least 5
times their weight of an aqueous 0.9% saline solution as measured
using the Centrifuge Retention Capacity test (Edana 441.2-01). In
one embodiment, the absorbent material 283 is absorbent polymer
material which is in particulate form so as to be flowable in the
dry state.
[0163] As previously discussed, the absorbent material 283 present
in the absorbent cores 28 of an absorbent article and more
particularly illustrated in FIGS. 8-10, does not need to be present
along the entire length of the absorbent core. In one embodiment,
the back section 328 of an absorbent article includes an
insignificant amount of absorbent material 283 whereas at least the
middle 228 and/or the front section 128 include a greater amount of
absorbent material than the back section 328. For example, the back
section 328 may include less than 5 grams, or less than 3 grams,
less than 2 grams or even less than 1 g of a particulate absorbent
polymer material. The middle section 228 may include at least 5
grams, or at least 8 grams, or even at least 10 grams of a
particulate absorbent polymer material. The front section 128 may
include between 1 and 10 grams, or between 2 and 8 grams of a
particulate absorbent polymer material.
[0164] In addition, it should be noted that the front and back
edges of the absorbent chassis of the article are shown as being
linear in FIGS. 1A through 3B. However, either the back and/or the
front edges may have a shape other than linear. Suitable non-linear
shapes are disclosed in U.S. Pat. No. 7,361,167 issued on Apr. 22,
2008, to Erickson et al. and assigned to The Procter and Gamble
Company.
[0165] In one embodiment, at least one of, or even both the
nonwoven layers 281 and 284 of an absorbent core extend from a
portion of the front section 128, which is proximate the front edge
of the absorbent article, to a portion of the back section 328
(inclusive of the middle section 228), which is proximate the back
edge of the absorbent article. The absorbent material 283 may be
present in the absorbent core along substantially the whole length
of the nonwoven layers 281 and 284 as schematically represented in
FIG. 11 with the absorbent material 283 represented with angled
lines. It may be advantageous to include absorbent material 283 in
the front and middle sections 128, 228 of the absorbent article but
to limit the overall amount of absorbent material in the back
section of the absorbent article such that the transverse axis Te
of the ears and/or Tf of the fastening tabs go through a region of
the absorbent core, which includes less absorbent material than the
front and middle sections 128, 228. In one embodiment schematically
represented in FIG. 12, the absorbent material 283 may be applied
on the portion of the absorbent core present in the back section
but at a lower basis weight than the absorbent material present in
the middle section 228. In another embodiment schematically
represented in FIG. 13, the absorbent material 283 may be disposed
in only a portion of the back section 328 leaving the portion of
the back section proximate the back edge of the absorbent article
with only an insignificant amount of absorbent material. In yet
another embodiment schematically represented in FIG. 14, the
portion of the absorbent core 28 disposed in the back section 328
includes an insignificant amount of absorbent material or even no
absorbent material. In one embodiment schematically represented in
FIG. 15, at least one of, or even both the nonwoven layers 281 and
284 of an absorbent core extend from a portion of the front section
128, which is proximate the front edge of the absorbent article, to
a portion of the back section 328 (inclusive of the middle section
228), which is proximate the line that separates the middle and
back sections 328. An absorbent material 283 is disposed between
the nonwoven layers 281, 284 leaving a substantially portion of the
back section 328 with essentially no absorbent core. Among other
benefits, it is believed that limiting the overall amount of
absorbent material 283 in the back section 328 renders the back
section 328 more flexible and allows the back section to better
conform and remain in close contact with the skin of the
wearer.
Peak Bending Force.
[0166] As previously discussed, it can be advantageous to provide
an absorbent article having at least a back section that is
flexible. This may be accomplished by significantly reducing the
amount of cellulosic material present in the portion of the
absorbent core present in the back section of the absorbent
article. It is believed that a cellulosing material can stiffen
regions of the article where it is present, in particular when a
stack of folded absorbent articles are compressed to be packaged.
Additional flexibility may further be obtained by significantly
reducing the amount of absorbent material present in the portion of
the absorbent core, which is present in the back section of the
article. Further flexibility may also be obtained by reducing the
amount of thermoplastic adhesive material present in the portion of
the absorbent core, which is present in the back section of the
article. In one embodiment, the Average Peak Bending Force of the
rear region of back section 38 of an absorbent article is less than
0.08N, less than 0.07N, less than 0.06N or even less than
0.05N.
Bending Stiffness Measurement Method
[0167] Peak Bending Force and Bending Stiffness are measured using
a constant rate of extension tensile tester with computer interface
(a suitable instrument is an MTS Alliance under TestWorks 4
software, as available from MTS Systems Corp., Eden Prairie, Minn.)
fitted with a 10 N load cell. A plunger blade 2100, shown in FIG. 9
(front view) and FIG. 10 (side view), is used for the upper movable
test fixture. Base support platforms 2200, shown in FIG. 8, are
used as the lower stationary test fixture. All testing is performed
in a conditioned room maintained at about 23.degree. C..+-.2 C and
about 50%.+-.2% relative humidity.
[0168] Components of the plunger 2100 are made of a light weight
material such as aluminum to maximize the available load cell
capacity. The shaft 2101 is machined to fit the tensile tester and
has a locking collar 2102 to stabilize the plunger and maintain
alignment orthogonal to base support platforms 2204. The blade
2103, is 115 mm long 2108 by 65 mm high 2107 by 3.25 mm wide 2109,
and has a material contact edge with a continuous radius of 1.625
mm. The bracket 2104 is fitted with set screws 2105 that are used
to level the blade and a main set screw 2106 to firmly hold it in
place after adjustment.
[0169] The bottom fixture 2200 is attached to the tensile tester
with the shaft 2201 and locking collar 2202. Two horizontally
movable support platforms 2204 are mounted on a rail 2203. Each
test surface 2205 is 85 mm wide 2206 by 115 mm long (into plane of
drawing) and made of polished stainless steel so as to have a
minimal coefficient of friction. Each platform has a digital
position monitor 2208 which reads the individual platform
positions, and set screws 2207 to lock their position after
adjustment. The two platforms 2204 are square at the gap edge and
the plate edges should be parallel front to back. The two platforms
form a gap 2209 with an adjustable gap width 2210.
[0170] Accurately (.+-.0.02 mm) align the plunger blade 2103 so
that it is orthogonal to the top surface of the support platforms
2204 and exhibits no skew relative to their gap edges. Using the
position monitors 2208, accurately set the gap 2210 to
25.00.+-.0.02 mm between the two gap edges of the support platforms
2204, with the plunger blade 2103 accurately (.+-.0.02 mm) centered
in the gap. Set the gauge length from the bottom of the plunger
blade 2103 to the top surface of the support platform 2204 to 15
mm. Program the tensile tester to perform a compression test,
collecting force and extension data at an acquisition rate of 400
Hz as the crosshead lowers at a rate of 500 mm/min for a total
distance of 35 mm.
[0171] Precondition samples at about 23.degree. C..+-.2 C..degree.
and about 50%.+-.2% relative humidity for 2 hours prior to testing.
The absorbent article is unfolded and placed with the wearer-facing
surface facing upward. Using scissors cut the elastics along the
longitudinal edges of the article at an interval of approximately 2
cm, such that the article can be laid flat. With a calibrated
ruler, measure the longitudinal length of the article to the
nearest 1 mm. Measure a distance equal to 20% of the article's
longitudinal length, originating from the back waist edge of the
article, along the longitudinal axis of the article. Mark the
surface of the article at this intersection. With a hydraulic press
and cutting die (63.5 mm square.+-.0.1 mm and 25 mm deep), cut a
specimen centered on this mark through all the layers of the
absorbent article with the specimen's cut edges parallel and
perpendicular to the longitudinal and lateral axis of the
article.
[0172] Place the specimen flat onto the surface of the support
platform 2204 over the gap 2209 with the wearer-facing surface
facing upward. Center the specimen 1009 under the blade. The
specimen is placed such that the direction corresponding to the
lateral axis of the absorptive article it was harvested from is
parallel to the length of the blade. Zero the load cell; start the
tensile tester and the data acquisition.
[0173] Program the software to calculate the maximum Peak Bending
Force (N) and
[0174] Stiffness (N/m) from the constructed force (N) verses
extension (m) curve. Stiffness is calculated as the slope of the
bending force/extension curve for the linear region of the curve
(see FIG. 11), using a minimum line segment of at least 25% of the
total peak bending force to calculate the slope.
[0175] Report Peak Bending Force to the nearest 0.01 N and the
Bending Stiffness to the nearest 0.1 N/m, and record the results.
Repeat the test and record the results for 10 samples. Calculate
the average Peak Bending Force and average Bending Stiffness.
Examples
TABLE-US-00003 [0176] Average Peak Bending Standard Product name
Force at Waist (N) Deviation Example A 0.06 0.02 Pampers Cruisers
(Size 4) 0.14 0.03 Pampers Easy Ups (Size 5) 0.82 0.1 Pampers Baby
Dry (Size 5) 0.12 0.03 Luvs (Size 4) 0.10 0.02 Luvs (Size 2) 0.08
0.01 Huggies Little Movers (Size 5) 0.64 0.06 Huggies Snug &
Dry (Size 5) 0.96 0.28 Huggies Pull Ups (Size 3T/3T) 0.82 0.21
Target Brand (Size 5) 0.3 0.03 Pampers and Luvs products are
manufactured by The Procter & Gamble Company Huggies products
are manufactured by Kimberly-Clark Example A is representative of
one embodiment of the invention and include an absorbent core
described in the context of FIG. 10.
[0177] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention. To the
extent that any definition or meaning of a term in this written
document conflicts with any definition or meaning of the term in a
document incorporated by reference, the definition or meaning
assigned to the term in this document shall govern.
[0178] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It should be apparent that combinations of such
embodiments and features are possible and can result in executions
within the scope of this invention. It is therefore intended to
cover in the appended claims all such changes and modifications
that are within the scope of this invention.
* * * * *