U.S. patent application number 11/810741 was filed with the patent office on 2008-01-03 for absorbent article having an anchored core assembly.
Invention is credited to Fred Naval Desai, Bruno Johannes Ehrnsperger, Frederick Michael Langdon, Richard Worthington Lodge, Luke Robinson Magee, Donald Carroll Roe.
Application Number | 20080004591 11/810741 |
Document ID | / |
Family ID | 38508734 |
Filed Date | 2008-01-03 |
United States Patent
Application |
20080004591 |
Kind Code |
A1 |
Desai; Fred Naval ; et
al. |
January 3, 2008 |
Absorbent article having an anchored core assembly
Abstract
Embodiments of the present disclosure include disposable
wearable absorbent articles with anchoring systems. In an
embodiment, a disposable wearable absorbent article includes an
absorbent core assembly including an absorbent core with an
absorbent core end, wherein at least a portion of the absorbent
core assembly extends past the absorbent core end and the portion
is configured to constrain the absorbent core end.
Inventors: |
Desai; Fred Naval;
(Fairfield, OH) ; Lodge; Richard Worthington;
(Colerain Township, OH) ; Roe; Donald Carroll;
(West Chester, OH) ; Ehrnsperger; Bruno Johannes;
(Hessen, DE) ; Langdon; Frederick Michael; (Blue
Ash, OH) ; Magee; Luke Robinson; (Cincinnati,
OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY;INTELLECTUAL PROPERTY DIVISION - WEST BLDG.
WINTON HILL BUSINESS CENTER - BOX 412
6250 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
38508734 |
Appl. No.: |
11/810741 |
Filed: |
June 7, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11599862 |
Nov 15, 2006 |
|
|
|
11810741 |
Jun 7, 2007 |
|
|
|
60811580 |
Jun 7, 2006 |
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Current U.S.
Class: |
604/396 ;
604/397; 604/401 |
Current CPC
Class: |
A61F 13/5148 20130101;
A61F 13/49 20130101; A61F 13/51496 20130101; A61F 13/66 20130101;
A61F 13/51474 20130101; A61F 13/64 20130101; A61F 13/496 20130101;
A61F 13/74 20130101 |
Class at
Publication: |
604/396 ;
604/397; 604/401 |
International
Class: |
A61F 13/496 20060101
A61F013/496 |
Claims
1. A disposable wearable absorbent article comprising an absorbent
core assembly including an absorbent core with an absorbent core
end, wherein at least a portion of the absorbent core assembly
extends past the absorbent core end and the portion is configured
to constrain the absorbent core end.
2. The disposable wearable absorbent article of claim 1, including
an outer cover, wherein the absorbent core assembly is shorter than
the outer cover.
3. The disposable wearable absorbent article of claim 1, including
an outer cover, wherein the absorbent core assembly is about as
long as the outer cover.
4. The disposable wearable absorbent article of claim 1, wherein
the portion is incrementally stretched.
5. The disposable wearable absorbent article of claim 1, including
an outer cover, wherein the portion is attached to the outer cover
at an attachment location.
6. The disposable wearable absorbent article of claim 5, wherein
the attachment location is adjacent to an end edge of the
article.
7. The disposable wearable absorbent article of claim 1, wherein
the absorbent core assembly includes a topsheet, which includes the
portion.
8. The disposable wearable absorbent article of claim 1, wherein
the absorbent core assembly includes a backsheet, which includes
the portion.
9. The disposable wearable absorbent article of claim 1, wherein
the absorbent core assembly includes a barrier leg cuff, which
includes the portion.
10. The disposable wearable absorbent article of claim 1, wherein
the absorbent core assembly includes a core cover, which includes
the portion.
11. The disposable wearable article of claim 1, including an outer
cover, wherein the absorbent core assembly is bonded to the outer
cover with one or more bonds that together cover a particular bond
area that is less than 20 cm.sup.2.
12. The disposable wearable article of claim 11, wherein the one or
more bonds are a single bond area.
13. The disposable wearable article of claim 1, including an outer
cover, wherein the absorbent core covers a particular core area and
the absorbent core assembly is bonded to the outer cover with one
or more bonds that together cover a particular bond area that is
less than 20 percent of the particular core area.
14. The disposable wearable article of claim 13, wherein the one or
more bonds are a single bond area.
15. The disposable wearable article of claim 1, including an outer
cover, wherein the absorbent core assembly is bonded to the outer
cover only in a longitudinally central region of the absorbent
core.
16. The disposable wearable article of claim 1, including an outer
cover, wherein the absorbent core assembly is bonded to the outer
cover only in a laterally central region of the absorbent core.
17. The disposable wearable article of claim 1, including an outer
cover, wherein the absorbent core assembly is bonded to the outer
cover with a bond that is longitudinally elongated.
18. The disposable wearable article of claim 1, including an outer
cover, wherein the absorbent core assembly is bonded to the outer
cover with a bond that extends over substantially all of a
longitudinal length of the absorbent core.
19. The disposable wearable article of claim 1, including an
anchoring system configured to anchor the absorbent core assembly
to a wearer.
20. The disposable wearable absorbent article of claim 1, including
an outer cover, wherein the outer cover is stretchable in at least
one direction.
21. The disposable wearable absorbent article of claim 1, including
an outer cover, wherein the outer cover is a zero-strain
laminate.
22. The disposable wearable absorbent article of claim 1, wherein
the article is a fastenable disposable wearable absorbent
article.
23. The disposable wearable absorbent article of claim 1, wherein
the article is a pant-type disposable wearable absorbent article.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/599,862, filed on Nov. 15, 2006, which claims the benefit of
U.S. Provisional Application No. 60/811,580, filed Jun. 7, 2006,
both of which are hereby incorporated by reference. This
application also claims the benefit of U.S. Provisional Application
No. 60/811,580, filed Jun. 7, 2006.
FIELD OF INVENTION
[0002] This invention relates to absorbent articles generally, and
in particular relates to an absorbent article having an absorbent
core and an anchoring system that supports the core assembly of the
absorbent article.
BACKGROUND OF THE INVENTION
[0003] It has long been known that absorbent articles such as
conventional taped diapers, pull-on diapers, training pants,
incontinence briefs, and the like, offer the benefit of receiving
and containing urine and/or other bodily exudates. Such absorbent
articles can include a chassis that defines a waist opening and a
pair of leg openings. A pair of barrier leg cuffs can extend from
the chassis toward the wearer adjacent the leg openings, thereby
forming a seal with the wearer's body to improve containment of
liquids and other body exudates. Conventional chassis include a
core that is disposed between a topsheet and a garment-facing outer
cover (also known as a backsheet).
[0004] The outer cover can include a stretchable waistband at one
or both of its ends (e.g., proximal opposing laterally extending
edges), stretchable leg bands surrounding the leg openings, and
stretchable side panels, which can be integral or separate discrete
elements attached directly or indirectly to the outer cover. The
remainder of the outer cover typically comprises a non-stretchable
nonwoven-breathable film laminate. Unfortunately, such diapers do
not conform well to the wearer's body during different body
movements, e.g. sitting, standing, and walking due to the relative
anatomic dimensional changes (which can, in some instances, be up
to 50%) in the buttocks region caused by these movements. This
problem is further exacerbated by the fact that one diaper
typically has to fit all the wearers in a given size range.
[0005] The dimensions of the smallest and biggest wearers within a
given size range can be markedly different. For instance the waist
circumference at the navel can vary by 80 mm within a given size
range. Also, the navel-to-back distance, which is the distance from
the navel, through the crotch, and to a point on the back of the
wearer that is in the same horizontal plane as the navel, can vary
by about 80 mm from the smallest to the largest wearers in this
same size.
[0006] In addition, it has been determined that caregivers and
wearers prefer the look and feel of cotton underwear (not provided
by conventional disposable diapers) for several reasons. For
instance, cotton underwear include elastic waist and leg bands that
encircle the waist and leg regions of the wearer and provide forces
that keep the underwear on the wearer's body. Furthermore, the
cotton outer cover (except in the waist and leg bands) can be
stretched along the width and length directions in response to a
relatively low force to accommodate the anatomic dimensional
differences related to movement and different wearer positions. The
stretched portion returns back to substantially its original
dimension once the applied force is removed. In other words, the
cotton outer cover of the underwear has low-force, recoverable
biaxial stretch that provides a conforming fit to a wider array of
wearer sizes than conventional diapers.
[0007] An effort has therefore begun to develop diapers that
simulate the look and feel of traditional cotton underwear.
However, diapers, unlike cotton underwear, are designed to receive
and retain loads (i.e., bodily exudates) that are received during
use while minimizing or eliminating leakage. It has been found that
the downward forces resulting from these loads cause biaxially
stretchable outer covers from the prior art to sag, droop, or
otherwise distend to the detriment of the fit of the diaper on the
wearer. Sagging is generally unsightly, and can cause leakage of
the bodily exudates due to, for example, displacement of the
barrier leg cuffs away from the wearer's body.
[0008] What is therefore needed is an absorbent article including
an anchoring system which is capable of supporting the core
assembly thereby supporting the (downward) force(s) exerted by the
core assembly. Additionally, what is needed is an absorbent article
capable of including a bi-axially stretchable outer cover while
minimizing occurrences of sagging of the outer cover and leakage
during use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Reference is hereby made to the following figures in which
like reference numerals correspond to like elements throughout, and
in which:
[0010] FIG. 1A illustrates a plan view of an embodiment of a
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0011] FIG. 1B illustrates a cross-sectional view of the disposable
absorbent article of FIG. 1A, according to the present
disclosure.
[0012] FIG. 1C illustrates a cross-sectional view of the disposable
absorbent article of FIG. 1A, according to the present
disclosure.
[0013] FIG. 2A illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0014] FIG. 2B illustrates a front view of the anchoring system and
absorbent core of FIG. 2A, according to the present disclosure.
[0015] FIG. 2C illustrates a back view of the anchoring system and
absorbent core of FIG. 2A, according to the present disclosure.
[0016] FIG. 3A illustrates a plan view of an embodiment of
anchoring bands attached to an absorbent core, according to the
present disclosure.
[0017] FIG. 3B illustrates a plan view of an embodiment of
anchoring bands attached to an absorbent core, according to the
present disclosure.
[0018] FIG. 4A illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0019] FIG. 4B illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0020] FIG. 4C illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0021] FIG. 5A illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0022] FIG. 5B illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0023] FIG. 6 illustrates a perspective view of an embodiment of an
anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0024] FIG. 7A illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0025] FIG. 7B illustrates a perspective view of an embodiment of
an anchoring system joined to an absorbent core, for use in a
disposable absorbent article, according to the present
disclosure.
[0026] FIG. 8 illustrates a plan view of an embodiment of an
anchoring system integrally formed into to an outer cover, for use
in a disposable absorbent article, according to the present
disclosure.
[0027] FIG. 9 illustrates a side view of an embodiment of an
absorbent article as worn on a wearer, according to the present
disclosure.
[0028] FIG. 10 illustrates a perspective view of an embodiment of
package of absorbent articles, according to the present
disclosure.
[0029] FIG. 11 illustrates a plan view of an embodiment of
disposable absorbent article with an absorbent core, an anchoring
system, and a waist cover, according to the present disclosure.
[0030] FIG. 12A illustrates a plan view of an embodiment of
disposable absorbent article with an absorbent core, an anchoring
system, and a waist cover, according to the present disclosure.
[0031] FIG. 12B illustrates a plan view of an embodiment of
disposable absorbent article with a carrier web for core end
management, according to the present disclosure.
[0032] FIG. 12C illustrates a plan view of an embodiment of
disposable absorbent article with an activated topsheet for core
end management, according to the present disclosure.
[0033] FIG. 13A illustrates a plan view of an embodiment of
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0034] FIG. 13B illustrates a cross-sectional view of the
disposable absorbent article of FIG. 13A, according to the present
disclosure.
[0035] FIG. 13C illustrates a cross-sectional view of the
disposable absorbent article of FIG. 13A, according to the present
disclosure.
[0036] FIG. 13D illustrates a cross-sectional view of the
disposable absorbent article of FIG. 13A, according to the present
disclosure.
[0037] FIG. 13E illustrates a cross-sectional view of the
disposable absorbent article of FIG. 13A, according to the present
disclosure.
[0038] FIG. 14 illustrates a plan view of an embodiment of
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0039] FIG. 15A illustrates a plan view of an embodiment of
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0040] FIG. 15B illustrates a cross-sectional view of the
disposable absorbent article of FIG. 15A, according to the present
disclosure.
[0041] FIG. 15C illustrates a cross-sectional view of the
disposable absorbent article of FIG. 15A, according to the present
disclosure.
[0042] FIG. 15D illustrates a cross-sectional view of the
disposable absorbent article of FIG. 15A, according to the present
disclosure.
[0043] FIG. 15E illustrates a cross-sectional view of the
disposable absorbent article of FIG. 15A, according to the present
disclosure.
[0044] FIG. 15F illustrates an embodiment of elements of an
anchoring system for use in a disposable absorbent article,
according to the present disclosure.
[0045] FIG. 15G illustrates an embodiment of elements of an
anchoring system for use in a disposable absorbent article,
according to the present disclosure.
[0046] FIG. 16 illustrates a plan view of an embodiment of a
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0047] FIG. 17 illustrates a plan view of an embodiment of a
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0048] FIG. 18 illustrates a plan view of an embodiment of a
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0049] FIG. 19A illustrates a plan view of an embodiment of a
disposable absorbent article with an absorbent core and an
anchoring system, according to the present disclosure.
[0050] FIG. 19B illustrates a cross-sectional view of the
disposable absorbent article of FIG. 19A, according to the present
disclosure.
[0051] FIG. 20A illustrates a plan view of an embodiment of
disposable absorbent article with an anchoring system, including a
stretchable portion, according to the present disclosure.
[0052] FIG. 20B illustrates a plan view of an embodiment of
disposable absorbent article with an anchoring system, including a
stretchable portion, according to the present disclosure.
[0053] FIG. 20C illustrates a plan view of an embodiment of
disposable absorbent article with an anchoring system, including a
stretchable portion, according to the present disclosure.
[0054] FIG. 21 illustrates a perspective view of a portion of a
human body along with a coordinate system.
[0055] FIG. 22 illustrates a perspective view of a human body with
force vectors relating to an anchoring system for a disposable
absorbent article, according to the present disclosure.
[0056] FIG. 23 illustrates another perspective view of a human body
with force vectors relating to an anchoring system for a disposable
absorbent article, according to the present disclosure.
[0057] FIG. 24A illustrates a perspective view of a human body with
force vectors relating to a particular embodiment of an anchoring
system for a disposable absorbent article, according to the present
disclosure.
[0058] FIG. 24B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 24A, according to the present
disclosure.
[0059] FIG. 24C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 24B, according
to the present disclosure.
[0060] FIG. 25A illustrates a perspective view of a human body with
force vectors relating to another particular embodiment of an
anchoring system for a disposable absorbent article, according to
the present disclosure.
[0061] FIG. 25B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 25A, according to the present
disclosure.
[0062] FIG. 25C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 25B, according
to the present disclosure.
[0063] FIG. 26A illustrates a perspective view of a human body with
force vectors relating to yet another particular embodiment of an
anchoring system for a disposable absorbent article, according to
the present disclosure.
[0064] FIG. 26B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 26A, according to the present
disclosure.
[0065] FIG. 26C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 26B, according
to the present disclosure.
[0066] FIG. 27 illustrates a perspective view of an embodiment of
an anchoring system for a disposable absorbent article, according
to the present disclosure.
[0067] FIG. 28A illustrates a perspective view of a human body with
force vectors relating to still another particular embodiment of an
anchoring system for a disposable absorbent article, according to
the present disclosure.
[0068] FIG. 28B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 28A, according to the present
disclosure.
[0069] FIG. 28C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 28B, according
to the present disclosure.
[0070] FIG. 29A illustrates a perspective view of a human body with
force vectors relating to a further particular embodiment of an
anchoring system for a disposable absorbent article, according to
the present disclosure.
[0071] FIG. 29B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 29A, according to the present
disclosure.
[0072] FIG. 29C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 29B, according
to the present disclosure.
[0073] FIG. 30A illustrates a perspective view of a human body with
force vectors relating to a still further particular embodiment of
an anchoring system for a disposable absorbent article, according
to the present disclosure.
[0074] FIG. 30B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 30A, according to the present
disclosure.
[0075] FIG. 30C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 30B, according
to the present disclosure.
[0076] FIG. 31A illustrates a perspective view of a human body with
force vectors relating to a yet further particular embodiment of an
anchoring system for a disposable absorbent article, according to
the present disclosure.
[0077] FIG. 31B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 31A, according to the present
disclosure.
[0078] FIG. 31C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 31B, according
to the present disclosure.
[0079] FIG. 32A illustrates a perspective view of a human body with
force vectors relating to an additional particular embodiment of an
anchoring system for a disposable absorbent article, according to
the present disclosure.
[0080] FIG. 32B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 32A, according to the present
disclosure.
[0081] FIG. 32C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 32B, according
to the present disclosure.
[0082] FIG. 33A illustrates a perspective view of a human body with
force vectors relating to another additional particular embodiment
of an anchoring system for a disposable absorbent article,
according to the present disclosure.
[0083] FIG. 33B illustrates a perspective view of the anchoring
system for the force vectors of FIG. 33A, according to the present
disclosure.
[0084] FIG. 33C illustrates a perspective view of the disposable
absorbent article for the anchoring system of FIG. 33B, according
to the present disclosure.
[0085] FIG. 34 illustrates a top view of force vectors relating to
an embodiment of an anchoring system for a disposable absorbent
article, according to the present disclosure.
[0086] FIG. 35 illustrates a top view of force vectors relating to
an embodiment of an anchoring system for a disposable absorbent
article, according to the present disclosure.
[0087] FIG. 36 illustrates a portion of an element of an anchoring
system, according to embodiments of the present disclosure.
[0088] FIG. 37 illustrates a force band with a point load,
according to embodiments of the present disclosure.
[0089] FIG. 38 illustrates a force band with two point loads,
according to embodiments of the present disclosure.
[0090] FIG. 39 illustrates a force band with a distributed load,
according to embodiments of the present disclosure.
[0091] FIG. 40 illustrates another portion of an element of an
anchoring system, according to embodiments of the present
disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Definitions:
[0092] As used herein, the following terms shall have the meaning
specified thereafter:
[0093] The term "disposable," as used herein 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).
[0094] The term "absorbent article" as used herein 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.
[0095] The term "diaper" as used herein refers to an absorbent
article generally worn by infants and incontinent persons about the
lower torso so as to encircle the waist and legs of the wearer and
that is specifically adapted to receive and contain urinary and
fecal waste. As used herein, term "diaper" also includes "pants"
which is defined below.
[0096] The terms "proximal" and "distal" as used herein refer
respectively to the location of an element relatively near to or
far from the center of a structure (e.g., the proximal edge of a
longitudinally extending element is located nearer to the
longitudinal axis than the distal edge of the same element is
located relative to the same longitudinal axis).
[0097] The terms "body-facing", "inner-facing", "outer-facing", and
"garment-facing" as used herein refer respectively to the relative
location of an element or a surface of an element or group of
elements. "Body-facing" and "inner-facing" imply the element or
surface is nearer to the wearer during wear. "Garment-facing" and
"outer-facing" imply the element or surface is more remote from the
wearer during wear (i.e., element or surface is nearer to the
wearer's garments that can be worn over the disposable absorbent
article).
[0098] The term "longitudinal" as used herein 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."
[0099] The term "lateral" as used herein 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."
[0100] "Longitudinal Centerline" refers to a longitudinal line that
can be drawn through the middle of an absorbent article. For most
absorbent articles, the longitudinal centerline separates the
article into two substantially symmetrical halves that will fall on
the left and right halves of a wearer during wear.
[0101] "Lateral Centerline" refers to a lateral line drawn through
the midpoint of the longitudinal centerline and perpendicular to
the longitudinal centerline.
[0102] The term "disposed" as used herein refers to an element
being attached and positioned in a particular place or position
with regard to another element.
[0103] "Liquid permeable" and "liquid impermeable" refer to the
penetrability of materials in the context of the intended usage of
disposable absorbent articles. Specifically, the term "liquid
permeable" refers to a layer or a layered structure having pores,
openings, and/or interconnected void spaces that permit liquid
water to pass through its thickness in the absence of a forcing
pressure. Conversely, the term "liquid impermeable" refers to a
layer or a layered structure through the thickness of which liquid
water cannot pass in the absence of a forcing pressure. Liquid
impermeable materials exhibit a hydrohead of at least about 5 mbar
as measured according to the Hydrostatic Head (Hydrohead) Pressure
Test provided below in the Test Methods. However, it may be
desirable that a liquid impermeable material exhibit a hydrohead of
at least about 10 mbar or about 15 mbar. A layer or a layered
structure that is water-impermeable according to this definition
may be permeable to vapor (i.e., may be "vapor permeable"). Such a
vapor permeable layer or layered structure is commonly known in the
art as "breathable."
[0104] As used herein the term "stretchable" refers to materials
which can stretch to at least an elongated length of 105% on the
upcurve of the hysteresis test at a load of about 400 gm/cm. The
term "non-stretchable" refers to materials which cannot stretch to
at least 5% on the upcurve of the hysteresis test at a load of
about 400 gm/cm.
[0105] The terms "elastic" and "elastomeric" as used herein refer
to any material that upon application of a biasing force, can
stretch to an elongated length of at least about 110%, preferably
to 125% of its relaxed, original length (i.e. can stretch to 10
percent, preferably 25% more than its original length), without
rupture or breakage, and upon release of the applied force,
recovers at least about 40% of its elongation, preferably recovers
at least 60% of its elongation, most preferably recovers at least
about 80% of its elongation. For example, a material that has an
initial length of 100 mm can extend at least to 110 mm, and upon
removal of the force would retract to a length of 106 mm (40%
recovery). The term "inelastic" refers herein to any material that
does not fall within the definition of "elastic" above.
[0106] The term "extensible" as used herein refers to any material
that upon application of a biasing force, can stretch to an
elongated length of at least about 110%, preferably 125% of its
relaxed, original length (i.e. can stretch to 10 percent,
preferably 25% more than its original length), without rupture or
breakage, and upon release of the applied force, shows little
recovery, less than about 40%, preferably less than about 20% and
more preferably less than about 10% of its elongation.
[0107] The terms "outboard" and "inboard" as used herein 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.
[0108] The term "anchoring zone" as used herein refers to an area
of contact between the diaper and wearer where at least a portion
of the load force is supported by the wearer's body. Multiple
anchoring zones can be desirable to increase diaper support. Once
their locations are identified, they map to corresponding zones in
the diaper.
[0109] The term "core assembly" as used herein refers to at least
an absorbent core and other optional structures (e.g., barrier
cuffs, liquid barrier layer, storage layer, acquisition layer,
distribution layer, etc.) to enhance containment of waste and/or
structures to enhance structural integrity.
[0110] The term "circumference" or "circumferential" as used
herein, refers to a closed path on the surface around the torso of
the body or around a leg. That path can have a smooth, continuous
curvature, or it can have "corners" where the curvature makes an
abrupt change, e.g. when the path passes through a connection zone
with three or more connecting tension-carrying bands.
[0111] The term "circumferential anchoring member", or "CAM", as
used herein, refers to one or more anchoring bands, that form a
substantially circumferential path (or partial circumferential
path) around at least a portion of a wearer that is joined to a
core assembly at both ends, for carrying tension that is
substantially in a defined path when the diaper is worn.
[0112] The term "force-decoupled" as used herein, refers to a
configuration of an absorbent article where movement of one element
or location in an article will not create a substantial force on a
second given element or location. In practice this typically means
that any material pathway that connects the two elements or
locations has enough slack or force attenuation such that the
movement of the first element does not induce substantial movement
in the second element. In some cases where more than one pathway
exists between the two elements or locations, it may be appropriate
to state that all or just particular pathways are
force-decoupled.
[0113] The terms "pant", "training pant", "pre-closed diaper",
"pre-fastened diaper", "pull-on diaper", and "pant-like garment" as
used herein, refer to disposable garments having a waist opening
and leg openings designed for infant or adult wearers. A pant can
be configured such that the pant has closed waist and leg openings
prior to being donned on the wearer, or the pant can be configured
such that the waist is closed and the leg openings formed while on
the wearer. A pant may be preformed by any suitable technique
including, but not limited to, joining together portions of the
article using refastenable and/or non-refastenable bonds (e.g.,
seam, weld, adhesive, cohesive bond, fastener, etc.). A pant may be
preformed anywhere along the circumference of the article (e.g.,
side fastened, front waist fastened, rear waist fastened), or at
the crotch. Examples of suitable pants are disclosed in U.S. Pat.
No. 5,246,433; U.S. Pat. No. 5,569,234; U.S. Pat. No. 6,120,487;
U.S. Pat. No. 6,120,489; U.S. Pat. No. 4,940,464; U.S. Pat. No.
5,092,861; U.S. Pat. No. 5,897,545; U.S. Pat. No. 5,957,908; and
U.S. Patent Publication No. 2003/0233082 A1.
[0114] The term "pre-closed" refers to an absorbent article that
has been formed into a pant-like garment prior to packaging such
that the end user receives the article as a pant-like garment that
can be directly applied to the wearer. The term "pre-closed" also
encompasses an absorbent article that can be closed by the end user
and formed into a pant-like garment prior to applying the garment
to the wearer.
[0115] As used herein, the terms "substantially" when referring to
a quantitative value are intended to include .+-.20% of the stated
quantitative value.
[0116] "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.
Description:
[0117] Absorbent articles of the present invention provide an
anchoring system which can support the (downward) forces exerted by
a core assembly. Additionally, some embodiments of the present
invention provide an absorbent article which includes a stretchable
outer cover while reducing the occurrences of sagging of the outer
cover and leakage during use.
[0118] In embodiments of the present disclosure, an absorbent
article having an anchoring system, as described herein, can
include a stretchable outer cover. For example, the outer cover can
be a uniaxially stretchable outer cover, configured to stretch in
one direction. Also as an example, the outer cover can be a
biaxially stretchable outer cover, configured to stretch in two
directions. In various embodiments, the outer cover can be
configured as described in U.S. non-provisional patent application
entitled "Biaxially Stretchable Outer Cover for an Absorbent
Article," filed on Nov. 15, 2006 with Express Mail No. EV916939625
and further identified by attorney docket number 10643, which is
hereby incorporated by reference.
[0119] In embodiments of the present disclosure, an absorbent
article having an anchoring system, as described herein, can be
configured with various structures and/or functions as described in
U.S. non-provisional patent application entitled "Disposable
Wearable Absorbent Articles With Anchoring Systems," filed on Nov.
15, 2006 with Express Mail No. EV916939648 and further identified
by attorney docket number 10628Q, which is hereby incorporated by
reference. Also, in embodiments of the present disclosure, an
absorbent article having an anchoring system, as described herein,
can have a wrap and tuck configuration as described in U.S.
non-provisional patent application entitled "Disposable Absorbent
Article Having a Wrap and Tuck Configuration," filed on Nov. 15,
2006 with Express Mail No. EV916939617 and further identified by
attorney docket number 10644, which is hereby incorporated by
reference.
[0120] Referring to FIG. 1A, an absorbent article constructed in
accordance with the present invention may comprise, in some
embodiments, a diaper 20. The diaper 20 may have a longitudinal
centerline 100 and a lateral centerline 110. The diaper 20, which
is illustrated in FIG. 1A as a pant-like garment, defines an inner
surface 50 and an opposing outer surface 52. The inner surface 50
generally includes that portion of the diaper 20 which is
positioned adjacent the wearer's body during use (i.e.,
wearer-facing), while the outer surface 52 generally comprises that
portion of the diaper 20 which is positioned away from the wearer's
body (i.e., garment-facing).
[0121] The diaper 20, in some embodiments, includes a chassis 21, a
core assembly 23, and an anchoring system 42. The chassis 21
includes a first, or front, waist region 36, a second, or back,
waist region 38 opposed to the front waist region 36, and a crotch
region 37 located between the front waist region 36 and the back
waist region 38. The waist regions 36 and 38 generally comprise
those portions of the diaper 20 which, when the diaper 20 worn,
encircle the waist of the wearer. The waist regions 36 and 38 can
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.
[0122] The outer periphery of the chassis 21 is defined by lateral
end edges 56 that can be oriented generally parallel to the lateral
centerline 110, and by longitudinal side edges 54 that can be
oriented generally parallel to the longitudinal centerline 100 or,
for better fit, can be curved or angled, as illustrated, to produce
an "hourglass" shaped garment when viewed in a plan view. In some
embodiments, the longitudinal centerline 100 can bisect the end
edges 56 while the lateral centerline 110 can bisect the side edges
54.
[0123] In some embodiments, the chassis 21 can comprise an outer
cover 24 extending between, and defining, the lateral end edges 56
and the longitudinal end edges 54. The outer cover 24 can
advantageously be stretchable in one or more directions, elastic in
one or more directions, preferably biaxially stretchable, and
preferably still biaxially elastic, thereby enhancing both the
comfort of the diaper 20 on the wearer and the conformability to
the wearer's anatomy during movement. In some embodiments, the
outer cover 24 may be non-stretchable. The outer cover 24 is
discussed further hereafter.
[0124] The diaper 20 may further comprise the core assembly 23
which can be positioned on a wearer-facing surface of the outer
cover 24. The core assembly 23 is the portion of the diaper 20
providing much of the absorptive and containment function. In some
embodiments, it may be desirable to attach the core assembly 23 to
the outer cover 24 in as few locations as possible; this can make
the outer cover 24 look and feel softer. However, in order to make
the design more tamper-resistant, it may be useful to attach the
core assembly 23 to the outer cover 24 along at least part, if not
all, of the core assembly's periphery; or a small distance (about
5-20 mm) inboard of the periphery. For example, the bond area
between the core assembly 23 and the outer cover 24 can be less
than about 70%, or, as another example, less than about 50%, or, as
yet another example, less than about 20% of the area of the core
assembly 23.
[0125] The core assembly 23 comprises a first portion 1536, a
second portion 1538, and a third portion 1537. As shown, the first
portion 1536 can be disposed, in part, in the first waist region
36. Similarly, the second portion 1538 and the third portion 1537
can be disposed, in part, in the second waist region 38 and the
crotch region 37, respectively.
[0126] Embodiments are contemplated where the core assembly 23 is
joined to the outer cover in a central region 1553 of the core
assembly 23. In some embodiments, the bond area can be between
about 1 cm.sup.2 and about 20 cm.sup.2 or any individual number
within the range. In some embodiments, the core assembly 23 may be
bonded to the outer cover 24 wherein the bond area resembles a
strip extending the substantial length of the core assembly, e.g.
being long and narrow.
[0127] As shown in FIG. 1B, the absorbent core assembly 23 may
include an absorbent core 26 that can be disposed symmetrically or
asymmetrically with respect to either or both of the longitudinal
centerline 100 and/or the lateral centerline 110. Similarly, the
core assembly 23 may be disposed symmetrically or asymmetrically
with respect to either or both the longitudinal centerline 100
and/or the lateral centerline 110. Referring back to FIG. 1A, the
absorbent core 26 and core assembly 23 are shown symmetrical with
respect to both the longitudinal centerline 100 and the lateral
centerline 110. The core assembly 23 is discussed further
hereafter.
[0128] As shown in FIG. 1B, in some embodiments, the core assembly
23 may comprise a topsheet 22 which can have a length and a width
dimensions that are substantially similar to those of the absorbent
core 26, while the outer cover 24 has length and width dimensions
generally larger than those of the absorbent core 26. The outer
cover 24 thus forms the periphery of the diaper 20.
[0129] Referring to FIG. 1A, the present invention recognizes that
the core 26 is capable of absorbing substantial loads during use,
and that the fit of conventional diapers can be worsened when the
increased weight and resultant (downward) forces exerted on the
core (and from the core to other diaper components) can cause the
diaper 20 to sag or otherwise be distended. Accordingly, the diaper
20 constructed in accordance with the principles of the present
invention includes the anchoring system 42 intended to fit to the
pelvic region of the wearer's torso region while directly
supporting the core assembly 23. As shown, in some embodiments, the
anchoring system 42 of the present invention may comprise a
plurality of load distribution elements (LDEs) 46 capable of
directing the load forces to at least a portion of the wearer's
waist region where the forces can be coupled into the wearer's
body. As a result, the anchoring system 42 can prevent, or
minimize, sagging during wear while the side edges and end edges,
54 and 56, respectively, move with the parts of the body
(spine/abdomen and legs, respectively) that can move relative to
the pelvis without being too uncomfortable/ creating too much
pressure for the wearer.
[0130] In some embodiments, the anchoring system 42 may include a
pair of anchoring bands that, as used herein, refer to structural
elements of the anchoring system of sufficient strength to carry
the forces involved in anchoring. Anchoring bands 44' and 44'' form
a first circumferential anchoring member (CAM) 44A (see FIGS.
2A-2C) when the front and back of the diaper are joined at the
sides to form a fastened diaper 20. FIGS. 2A-2C illustrate side,
front, and back, views of the anchoring system 42 that forms inside
the diaper 20 and independently supports the core assembly 23
(shown in FIG. 1A) when the diaper 20 is worn. Referring back to
FIG. 1A, the anchoring bands 44' and 44'' are capable of joining to
surround the wearer's body at the lower torso region. As shown, in
some embodiments, the anchoring bands 44' and 44'' can be disposed
longitudinally inboard of an elastic waistband 43 of the diaper
20.
[0131] The CAM 44 includes a first anchoring band 44' extending
between opposing side edges 54 in the front waist region 36, and a
second anchoring band 44'' extending between opposing side edges 54
in the back waist region 38. The anchoring bands 44' and 44'' are
disposed at a location proximal the corresponding end edges 56. In
the illustrated embodiment, the first anchoring band 44' converges
from the side edges 54 to a midpoint (aligned with the longitudinal
centerline 100) that is disposed further from the end edge 56 in
the front waist region 36 than the anchoring band 44' at the side
edges 54. The second anchoring band 44'' can be slightly curved
such that the anchoring band 44'' presents a convex surface edge
with respect to the end edge 56 at the back waist region 38. As
illustrated, the first and second anchoring bands 44' and 44'' may
be symmetrical with respect to the longitudinal centerline 100. One
skilled in the art will appreciate that anchoring bands 44' and
44'' can either be straight (e.g., extending substantially parallel
to lateral centerline 110 or extending straight but along a
direction that intersects the lateral centerline 110), can include
more than one straight section extending along a direction that
intersects a neighboring straight section, can include a curved
section, or can include a combination of curved and straight
sections. Furthermore, the anchoring bands 44' and 44'' can have
portions that are convex and/or concave with respect to the
corresponding end edges 56.
[0132] As shown in FIGS. 1B-1C, in some embodiments, the CAM 44 can
be attached to the wearer-facing surface of the outer cover 24 via
any suitable adhesive or cohesive or any suitable means known in
the art. When the diaper 20 is preformed into a pant, the anchoring
bands 44' and 44'' can be operatively connected via side seams 34
or closure members to form the continuous circumferential anchoring
member 44 that circumscribes the wearer's lower torso region.
[0133] The anchoring system 42, in some embodiments, may further
comprise one or more load distribution element(s) 46 (LDE(s)). For
example, as shown in FIG. 1A, a plurality of load distribution
elements (LDEs) 46 can be connected to the core assembly 23 and the
anchoring bands 44' and 44''. The LDEs 46 can be joined to the
anchoring bands 44' and 44'' and the core assembly 23 at connection
zones 48. The anchoring bands 44' and 44'' include one or more
connection zones 48 that are joined to the LDEs 46. As illustrated,
in some embodiments, the connection zones 48 are the points where
the LDEs 46 are joined to the CAM 44. As shown, in some
embodiments, the CAM 44 may comprise an even number of connection
zones 48 in the first waist region 36 and in the second waist
region 38, e.g. two in the first waist region and two in the second
waist region.
[0134] In one embodiment illustrated in FIG. 1A, four LDEs 46 may
be connected to the four corresponding corners of the core assembly
23. In the embodiment illustrated in FIGS. 1A-1C and 2A-2C, the
LDEs 46 may be connected to the garment-facing surface of the core
assembly 23 via any suitable adhesive, cohesive, thermal bonds, RF
bonds, pressure bonds, ultrasonic bonds, welds, stitches, or the
like. Alternatively, the LDEs 46 can be connected to the inner
(wearer-facing) surface of the core assembly 23, or to any of the
individual components of the core assembly 23. In some embodiments,
the LDEs 46 may extend laterally outward from the core assembly 23
and toward the corresponding end edge 56 and terminate at opposing
ends that are joined to the inner (i.e., body-facing) surface of
the CAM 44 at the connection zones 48 (see FIG. 1C). In some
embodiments, the LDEs 46 may be joined to the outer-facing surface
of the CAM 44. The LDEs 46 may be joined to the CAM 44 and to the
core assembly 23 by any suitable means known in the art. Some
suitable examples include adhesive, cohesive, or the like.
[0135] Additionally, in some embodiments, the LDEs 46 can either be
attached discretely to the outer cover 24 or may be integral with
the outer cover 24. For example, as shown, in some embodiments, the
LDEs 46 may be joined to the CAM 44 at one end and to the core
assembly 23 at the other, with the region in between being unbonded
and free to stretch. Alternately, the LDEs 46 may have a relatively
high force/modulus elastic that is either fully attached to or
embedded in the outer cover 24. An example of a suitable approach
to achieving the latter can be to print an elastomeric composition
on the outer cover 24 via standard elastomeric printing techniques
like gravure, offset gravure, flexographic, letterpress, screen,
and inkjet printing, and via other elastomer deposition techniques
like spraying and slot coating. Another example of a suitable
approach can be to print thermoplastic non-stretchable materials on
the outer cover 24 via standard thermoplastic printing techniques.
The formation of CAMs, LDEs and/or anchoring bands integral with
the outer cover 24 is discussed hereafter. Alternatively to
attaching the LDEs to the CAM, the LDE(s) and the CAM(s) can also
be made as a unitary structure, e.g. be made from the same
material. Likewise, part of the core (e.g. the NWDL or the BLC) can
be unitary with the LDE(s) and/or the CAM.
[0136] Referring to FIGS. 2A-2C, during use, when the core assembly
23 absorbs an excremental load, this incremental load gives rise to
additional gravitational as well as inertial forces. For example, a
gravitational load force is applied to the core assembly 23 which
tends to push the absorbent assembly 23 downward. The absorbent
assembly 23 transmits the gravitational load force to the LDEs 46
which in turn distribute the load force to the CAM 44A. The CAM 44A
in turn, transfers the gravitational load force to the wearer's
body (e.g., at the lower torso region). Part of the weight of the
core assembly 23 (one quarter if the core and urine loading are
symmetrical with respect to the longitudinal centerline and lateral
centerline) can be transmitted through each LDE 46 to the CAM
44A.
[0137] For any given urine load, the tension in the LDEs 46
increases as the angle of the LDEs 46 with respect to the
longitudinal centerline 100 (see beta shown in FIG. 1A,). Hence,
the larger the angle that a given LDE 46 makes with respect to the
vertical when the diaper 20 is donned on the wearer, the higher the
tensile force that the LDE 46 will apply to the CAM 44A. If the CAM
44A stretches substantially under this tensile load, particularly
between a connection zone 48 in the first waist region 36 and an
adjacent connection zone 48 in the second waist region 38, the
circumference of the CAM 44A may increase thereby causing the CAM
44A to lose some tension. Loss of tension by the CAM 44A may cause
the CAM 44A to move down until the CAM 44A finds a new equilibrium
location on the wearer's body. Accordingly, in certain aspects of
the present invention, the portion of the CAM 44A between a
connection zone 48 in the first waist region 36 and an adjacent
connection zone 48 in the second waist region 38 may be elastic,
extensile, or non-stretchable. In some embodiments, the portion of
the CAM 44A between adjacent connection zones 48, i.e. connection
zone in the first waist region and a connection zone in the second
waist region, can be elongated by less than about 50 mm. In other
embodiments, the connection zones 48 may have the same stretch
properties as the rest of the stretchable portions of the CAM
44A.
[0138] The LDEs 46, in some embodiments, can be joined to the CAM
44A such that an angle beta (shown in FIG. 1A) defined between a
given LDE 46 and the longitudinal centerline 100, can be between
about 10 and 80 degrees or any individual number within the range.
It should be appreciated, as is described in more detail below,
that numerous alternatives to the embodiment illustrated in FIGS.
1A-1C are contemplated.
[0139] Because the generally downward forces applied to the core
assembly 23 during use are transferred to the CAM 44A via the LDEs
46, the core assembly 23 can, in various embodiments, be supported
without any additional core-supporting structure. Further, the
performance of the anchoring system 42 can be enhanced if all other
potential pathways between the core assembly 23 and all parts of
the anchoring system 42 and the chassis are force-decoupled. With
this arrangement forces generated at the core 26 may follow a
pathway provided by the anchoring system 42 that bypasses the outer
cover 24 at the crotch region 37 and at a portion of the front and
back waist regions 36 and 38.
[0140] As will be described in more detail below, the anchoring
system 42 may define a geodesic network when the diaper 20 is worn
by the wearer in accordance with certain aspects of the invention.
It should be appreciated that the LDEs 46 can be arranged in any
desired manner such that they provide for the transmission of the
weight (gravitational and inertial forces) of the core assembly 23
and any of its contents (e.g. the elastic forces of the BLC being
part of the core assembly) to the anchoring system 42 thus
permitting the outer cover 24 to be rendered biaxially stretchable
or uniaxially stretchable without risk of substantial sagging
and/or distension due to the loads received by the core 26 during
use, especially if the core assembly is not stretchable or only
stretchable to a lesser degree than the outer cover 24 The biaxial
stretchability allows the outer cover 24 to conform to the wearer's
body in an underwear-like manner.
[0141] In embodiments comprising the stretchable outer cover 24,
the outer cover 24 can force-decouple a potential pathway between
the core assembly 23 and the anchoring system 42 ensuring that the
anchoring system 42 receives loads from the core assembly 23 only
by the LDEs 46 as opposed to receiving loads from the core assembly
23 by both the LDEs 46 and the outer cover 24. In some embodiments,
substantially all of the load from the core assembly 23 may be
transferred to the CAM 44A via the LDEs 46. In order to achieve the
force decoupling it may be desirable to minimize the coefficient of
friction between (a) the outer cover and the core, and (b) the
outer cover and the CAM and LDE.
[0142] As shown in FIGS. 3A and 3B, in some embodiments, the
anchoring system 42 may comprise anchoring bands 44' and 44'' which
are connected directly to the core assembly 23 without the use of
LDEs. For example, the anchoring band 44' can be connected to the
core assembly 23 in the first portion 1536 while the anchoring band
44'' can be connected to the core assembly 23 in the second portion
1538. For embodiments comprising the anchoring system 42 of FIG.
3A, the assembled diaper 20 (shown in FIG. 1A) includes a
continuous CAM 44A (shown in FIGS. 2A-2C). Specifically, for the
anchoring system 42 of FIG. 3A, the CAM 44A (shown in FIGS. 2A-2C)
is a closed loop and does not utilize a portion of the core
assembly 23 to close the loop about the waist of the wearer.
[0143] In contrast, embodiments comprising the anchoring system 42
of FIG. 3B include a discontinuous CAM 44A. Specifically, for the
anchoring system 42 of FIG. 3B, the CAM 44A is not a closed loop
and utilizes a portion of the core assembly 23 as an anchoring
system element to close the loop about the waist of the wearer. As
shown, in some embodiments, the anchoring band 44' can be connected
to the core assembly 23 in a first location 402 and a second
location 404. The first location 402 can be laterally spaced from
the second location 404. As shown, the first location 402 and the
second location 404 can be disposed in the first portion 1536
proximate to a first longitudinal edge 423A and a second
longitudinal edge 423B of the core assembly 23.
[0144] In some embodiments, the anchoring band 44'' can be
configured as shown in FIG. 3A or as shown in FIG. 3B. As shown in
FIG. 3B, in some embodiments, the anchoring band 44'' can be
connected to the core assembly 23 at a third location 406 and a
fourth location 408. The third location 406 can be laterally spaced
from the fourth location 408. Similar to the first location 402 and
the second location 404, the third location 406 and the fourth
location 408 may be disposed in the second portion 1538 proximate
to the first longitudinal edge 423A and second longitudinal edge
423B.
[0145] As shown in FIGS. 4A through 4C, embodiments are
contemplated wherein the anchoring member 44' is connected directly
to the core assembly 23 while the anchoring member 44'' is joined
to the core assembly 23 via LDEs 46 and vice versa. Connections
directly to the core assembly 23 include those discussed with
regard to FIGS. 3A and 3B. Similarly, embodiments are contemplated
where the anchoring band 44' is configured as described in FIG. 3A
while the anchoring band 44'' is configured as described in FIG.
3B, or vice versa.
[0146] Embodiments are contemplated where the anchoring system 42
comprises more than one CAM. For example, as shown in FIGS. 5A and
5B, the anchoring system 42 may comprise a first CAM 44A and a
second CAM 44B. The first CAM 44A can be connected to first portion
1536 of the core assembly 23 while the second CAM 44B is connected
to the second portion 1538 of the core assembly 23. As shown in
FIG. 4A, in some embodiments, a CAM can be continuous. In contrast,
as shown in FIG. 4B, in some embodiments, the core assembly 23 can
form an implied anchoring band to close the loop of a CAM. For the
embodiment shown in FIG. 4B, a CAM can be connected to the core
assembly as described with regard to FIG. 3B and the first location
402, second location 404, third location 406, and the fourth
location 408. In some embodiments, the anchoring system may be
configured as described with regard to FIG. 5A. However, instead of
being connected to the core assembly 23, a CAM can be joined to the
core assembly 23 via a plurality of LDEs.
[0147] With regard to FIGS. 5A and 5B, in some embodiments, the
first CAM 44A can be joined to the second CAM 44B proximal to a
point of intersection between the first CAM 44A and the second CAM
44B. By joining the first CAM 44A and the second CAM 44B to one
another, each of the CAMs can provide lateral stabilization to the
other CAM. The lateral stabilization can reduce the likelihood that
the first CAM 44A and/or the second CAM 44B will move relative to
the wearer during dynamic movement.
[0148] While the LDEs 46 may be directly connected to the CAM 44 as
described above with reference to FIG. 1A, it should be appreciated
that the present invention alternatively contemplates the CAM 44
connected to the LDEs 46 via an intermediate load element 1543
which may act as a connection zone 48, as illustrated in FIG. 6. As
shown in FIG. 6, in some embodiments, the LDEs 46 may comprise
elongated bands that are attached at one end to the core assembly
23 on either side of the longitudinal centerline 100 (and proximal
thereto), and are connected at their other ends to the intermediate
load element 1543. In turn, the intermediate load element 1543 may
act as the connection zone 48 which joins the LDEs 46 to the
corresponding anchoring band 44' or 44''. The properties of the
intermediate load element 1543 can be similar to the properties of
the CAM 44, anchoring bands 44' and 44'', and LDEs 46, discussed
hereafter.
[0149] Other embodiments of the present invention include a
stabilization band. For example, as shown in FIGS. 7A and 7B, the
anchoring system 42 may comprise a stabilization band 710 which is
joined to the first CAM 44A. As shown, in FIG. 7A, the
stabilization band 710 may be discontinuous. Specifically, as
shown, the stabilization band 710 may not be a closed loop
independently from the first CAM 44A. Alternatively, in some
embodiments, as shown in FIG. 7B, the stabilization band 710 may be
continuous, i.e. a closed loop independently from the first CAM
44.
[0150] Regardless of whether the stabilization band 710 is
continuous or discontinuous, the stabilization band can be joined
to the first CAM 44A thereby providing lateral support to the first
CAM 44A. For example, the stabilization band 710 can reduce the
likelihood that a portion of the first CAM 44A will slide down the
hip of the wearer during dynamic movement. In various embodiments,
a stabilization band can be non-stretch or elastic.
[0151] Additionally, the first CAM 44A can be joined to the core
assembly 23 as discussed heretofore. For example, the first CAM 44A
may be directly connected to the core assembly 23 in the front
portion 1536 (shown in FIG. 1A) and directly connected to the core
assembly 23 in the back portion 1538 (shown in FIG. 1A). As another
example, the first CAM 44A can be joined to core assembly 23 in the
front portion 1536 (shown in FIG. 1A) and/or the second portion
1538 (shown in FIG. 1A) via LDEs 46 (shown in FIG. 1A). As yet
another example, the first CAM 44A can be directly connected to the
core assembly 23 in the front portion 1536 (shown in FIG. 1A)
and/or the back portion 1538 (shown in FIG. 1A) as described
heretofore with regard to FIGS. 3A and 3B, 4A and 4C, and 5A and
5B.
[0152] The CAMs of the present invention can be made from any
suitable material known in the art. For example, the CAM can be an
elastomeric material in any form, e.g. extruded film, elastic
non-woven, scrim, slot-coated film, sprayed or meltblown fibers,
printed elastics, or any other suitable process known in the art
for manufacturing elastomeric material. In embodiments comprising
an outer cover (as described heretofore with regard to FIG. 1A),
the CAM may be attached to the outer cover either on line during
the diaper manufacturing process, or it may be incorporated into
the outer cover during the outer cover manufacturing process. An
example of the latter is elastomer printing, wherein, in a specific
embodiment, the print pattern on the printing roll is such that the
higher caliper region forms the higher-force CAM, while the lower
caliper region forms the rest of the outer cover. Anchoring systems
formed as a portion of the outer cover are discussed hereafter.
[0153] In some embodiments, the CAM may have a first cycle force
greater than about 50 grams at about 15% strain. In some
embodiments, the CAM may have a first cycle force of between about
75 grams and about 1000 grams or any individual number within the
range. In some embodiments, the CAM may have a first cycle load of
between about 100 grams and about 500 grams. In some embodiments,
the CAM may have a first cycle load of between about 150 grams and
about 300 grams. It should be noted that this force is measured at
the actual width of the CAM.
[0154] The CAM may be of any suitable width known in the art. For
example, in some embodiments, the CAM may vary in width from about
5 mm to about 75 mm or any individual number within the range. In
some embodiments, the CAM may vary in width from about 10 mm to
about 50 mm. In some embodiments, the CAM may vary in width from
about 15 mm to about 35 mm.
[0155] It should be appreciated that the CAM can have a variable
width and/or thickness along its length, either of which would
produce discrete regions on the CAM having different stretch
properties (e.g., that stretch to different extents). The variable
width and/or thickness could be achieved, for example, using an
elastomeric printing process appreciated by one having ordinary
skill in the art.
[0156] The CAM has higher modulus (slope of the stress-strain
curve) than the modulus of the outer cover to prevent excessive
sagging with each increment of load. The CAM, in some embodiments,
can have certain portions that are elastic and other portions that
are either extensible or non-stretchable (i.e. elastic over one or
more portions of its length and inelastic or non-stretchable over
the remaining portions). For example, a section of the CAM that is
connected to a non-stretchable core assembly need not be
stretchable, since this core assembly would prevent the CAM from
stretching.
[0157] The CAM stretches predominantly in the lateral direction. A
key part of the invention is that CAM has a higher tensile force
compared to the remainder of the outer cover. At 15% strain (first
cycle), the ratio of lateral CAM force per unit width to the
remainder of the outer cover or topsheet force per unit width is
greater than 1.5, more preferably greater than 2, even more
preferably greater than 5, and most preferably greater than 10.
[0158] In embodiments where the diaper is a pant, the CAM can be
elastic in order to allow the diaper to stretch in the lateral
direction during application, given that the initial diaper
circumference can be preset. This desirability can be increased
when a single size diaper is intended to fit a range of wearers in
a given size. In embodiments where the diaper is a taped diaper,
the size adjustability can be at least partially achieved by the
fastener placement on a landing zone or other fastener receiving
surface and, as a result, while the CAM can be elastic, a
non-stretchable, or extensible, CAM is similarly feasible.
[0159] The LDEs 46, in some embodiments, may be non-stretchable so
as to transfer the load forces at the core 26 to the connection
zone 48 of the CAM 44. The LDEs of the present invention may
comprise, in some embodiments an elastic material, an extensible
material, and/or a non-stretchable material. The LDEs 46 may be
formed utilizing any suitable material known in the art. For
example, the LDEs 46 can be formed from nonwovens, films,
elastomeric structures, and the like.
[0160] It should be appreciated that the LDEs 46 can alternatively
be extensible or stretchable, in which case they preferably have a
low strain force limit. For example, the LDEs 46 may be able to
stretch to some low level of strain, e.g. 50%. Beyond the strain of
50%, for example, the slope of the stress strain curve can increase
compared to the slope of the stress strain curve from 0% to 50%
strain. Such materials may be beneficial in reducing wet core
drooping due to wearer movements like walking and running. The low
strain force limit can be achieved, for example, with stretch
bonding, whereby an elastomeric film, filaments or nonwoven is
stretched in the machine direction, bonded to a substrate web, such
as a nonwoven, and allowed to retract and gather; or, as another
example, via incremental stretching to a relatively small level of
strain. For example, a nonwoven that comprises a mix of elastomeric
and non-elastomeric fibers/filaments is not elastic. However, upon
incremental stretching, the web may become elastic.
[0161] In general, incremental stretching can be used to release
the stretch properties of a composite that comprises elastic and
inelastic components, e.g. an elastic web laminated to an inelastic
web. In accordance with certain aspects of the present invention,
the low level of strain can be less than about 50%, alternatively
less than about 40%, alternatively still less than about 30%,
alternatively still less than about 25%, and alternatively still
less than about 20% for a linkage that is between about 50 and
about 150 mm long or any individual number within the range. The
extensibility/stretchability of the LDEs permits the diaper 20 to
expand in the longitudinal and lateral directions, thereby
providing a conforming fit for a wider range of wearers that is
improved with respect to conventional absorbent articles.
Furthermore, extensible or elastic LDEs 46 can accommodate wearer
movement during use, and further accommodate core swelling as loads
are deposited in the core 26.
[0162] In some embodiments, the load of the LDE at 15% strain
(first cycle) in the Hysteresis test is at least about 40 gm,
preferably more than about 75 gm and most preferably greater than
about 100 gm. In some embodiments, the LDEs 46 can have a width
ranging from about 5 mm to about 50 mm. It should be noted that the
sample width in the Hysteresis test should be the same as the width
of the LDE. Also, the length direction of the LDE is the direction
in which it is pulled in use. In some embodiments, the LDEs 46
and/or the CAM 44 may alternatively comprise a multiplicity of
subcomponents, such as strands or filaments, having individual
widths of less than 5 mm. In accordance with certain aspects of the
present invention, in some embodiments, the LDEs 46 are less
extensible (e.g., have a higher elastic modulus) than the outer
cover 24 to reduce the ability for wearer movement to cause the
core assembly 23 to bias the outer cover 24, e.g. cause the waist
and/or leg perimeters to move with respect to the wearer.
[0163] The integral formation of anchoring bands, CAMs, and/or LDEs
as part of the outer cover is contemplated in some embodiments. For
example, as shown in FIG. 8, in some embodiments, the LDEs 46
and/or the CAM 44 may be integrally formed in the outer cover 24 by
differential incremental stretching of the outer cover 24. The core
assembly has been omitted in FIG. 8 to show details of the integral
anchoring system. As shown, in some embodiments, portions of the
outer cover 24 that correspond to the LDEs 46, the anchoring band
44' and/or the anchoring band 44'', are either not incrementally
stretched or are stretched to a lesser extent compared to the rest
of the outer cover 24. In some embodiments, a first portion of the
CAM may be a discrete band or other separate element that is
attached to the chassis 21, while a second portion of
circumferential anchoring member is integral with the outer cover
24 to which the discrete band or other separate element is
attached.
[0164] As shown in FIG. 8, in some embodiments, the outer cover 24
may be joined to the LDEs 46 at their respective connection zones
48. Additionally, in some embodiments, the LDEs 46 may be integral
with the anchoring bands 44' and/or 44''. For example, in some
embodiments, the LDEs 46, the anchoring band 44', and the anchoring
bands 44'', may comprise a contiguous portion of underactivated or
nonactivated area. As shown, in some embodiments, where the LDEs 46
are integral with the outer cover 24, the outer cover 24 can be
joined to the core assembly 23 at the connection zones 48.
[0165] In accordance with one aspect of the present invention, if
the LDEs 46 are formed from the outer cover 24, the LDEs 46 can be
rendered extensible, non-stretchable, or elastic, such that the
forces exerted on the core 26 are transferred to the CAM 44 while
preventing the core 26 from substantially sagging. In embodiments,
where the LDEs 46 and/or the CAM 44 are integral with the outer
cover, the LDEs 46 and CAM 44 should have a higher modulus of
elasticity than the modulus of elasticity of other portions of the
outer cover 24 which do not comprise the LDEs 46 and/or the CAM
44.
[0166] The anchoring system of the present invention may have a
higher modulus compared to the rest of the outer cover. This higher
modulus can be achieved by using a higher caliper and/or higher
performance elastomer, via differential incremental stretching, or
over-bonding. Differential incremental stretching refers to
incremental stretching of different regions of a substrate to
different strain levels as described heretofore.
[0167] As described above, the circumferential anchoring member
and/or LDEs can either be integral with the biaxially stretchable
outer cover or be discretely attached to the biaxially stretchable
outer cover. In some embodiments, an integral anchoring system may
be created by differential incremental stretching of a biaxially
stretchable outer cover precursor. The term "biaxially stretchable
outer cover precursor" refers to a biaxially stretchable outer
cover prior to incremental stretching. The term "biaxially
stretchable" as used herein refers to the ability to stretch along
two orthogonal axes that extend coplanar with the outer cover. The
regions on the biaxially stretchable outer cover that correspond to
the anchoring system either are not incrementally stretched or are
stretched to a lesser extent compared to the rest of the biaxially
stretchable outer cover.
[0168] In some embodiments, an integral anchoring system includes
printing of an elastomeric composition in the areas where the
circumferential anchoring member and/or LDEs are located on the
biaxially stretchable outer cover precursor, followed by
differential incremental stretching wherein the anchoring system
components (i.e., LDEs and/or circumferential anchoring member) can
be stretched to a lesser extent compared to the rest of the
biaxially stretchable outer cover. The printing of the biaxially
stretchable outer cover elastomer and the anchoring system
elastomer onto the nonwoven substrate can be done in one step if
they are the same chemistry, or in multiple steps if they are
different chemistries. In some embodiments, non-stretch polymers
can be printed and/or deposited to make integral anchoring system
elements with non-stretch portions.
[0169] In some embodiments, the circumferential anchoring member
and/or LDEs can also be attached to the biaxially stretchable outer
cover discretely. An example is an on-line cut and slip process in
which these elements are cut from an elastomeric film or a
film-nonwoven laminate and attached to the biaxially stretchable
outer cover.
[0170] In accordance with the methods described herein, an
elastomer may be combined with a nonwoven web. The elastomer can be
in the form of a film, a nonwoven, a crosshatch pattern, stripes in
the lateral and/or longitudinal directions, stripes in any
direction, or any other shape, and is laminated to a nonwoven.
[0171] In some embodiments, the elastomer may be printed onto the
nonwoven web as described heretofore. The main advantage of
printing is that it has the capability of delivering a very small
amount of elastomer on the nonwoven, thus producing a low force
member. For example, a pattern that has 1 mm wide stripes that are
4 mm apart will have about one fifth the force of a solid film.
Another advantage of printing is that a small quantity of a high
performance elastomer can be used to deliver the desired force and
recovery properties, thus keeping manufacturing costs down.
Regardless of the method by which the elastomer and nonwoven web
are combined, the resultant web may be subjected to selective
incremental stretching in the areas of the web which are intended
to extend or stretch in use, i.e., during wearer movements. Any
areas of the web intended to form a portion of the anchoring system
(i.e., the CAM or LDEs) may be incrementally stretched to a lesser
degree than the surrounding portions of the web. The above
described can be applied to an absorbent article 120 of the
embodiment of FIG. 13A and to the absorbent article 20 discussed
heretofore.
[0172] The incorporation of anchoring systems into the articles of
the present invention enables the articles to fit higher on the
body initially (i.e., they do not "snap back" as much once
application tension is released), fit a broader range of wearer
"rises" (i.e., especially when biaxial outer cover stretch is
employed such that the product can adjust in the longitudinal
direction) and have a better sustained fit. It has been found that
these effects enable the reduction in the as-manufactured
longitudinal dimension (or "pitch") of the articles of the present
invention. This provides these articles a more underwear-like
appearance in their bi-folded state (i.e., when folded at their
lateral centerline only) since they have an aspect ratio (folded
height to width) similar to underwear. The articles of the present
invention may have an aspect ratio of from between about 1.2 and
about 0.7.
Outer Cover
[0173] As discussed previously, the outer cover may be stretchable
in one or more directions, elastic in one or more directions, or
non-stretchable. The side edges 54 of the outer cover 24 create
perimeters about the legs of a wearer, and similarly, the end edges
56 of the outer cover 24 create a waist perimeter about the wearer.
These perimeters can move relative to the anchoring system 42,
thereby changing the distances between the perimeters and the
anchoring system 42. For example, from a neutral standing position,
these distances increase particularly in the back region when the
knees are raised or the wearer bends forward at the waist.
[0174] In some embodiments, the waist and/or leg perimeters can be
force-decoupled from the anchoring system 42 by a bi-axially
stretchable outer cover 24, or "BSOC", that is designed to minimize
forces that arise between the waist or leg perimeters and the
anchoring system 42 from movement of the legs and spine relative to
the pelvis. In contrast, if the outer cover 24 were
non-stretchable, such movements may encumber the wearer, or such
movements may cause the perimeters to move relative to the waist
and leg regions of the wearer. It will be thus appreciated that the
anchoring system 42 and BSOC enables the diaper 20 to achieve an
enhanced, more comfortable and underwear-like fit relative to
conventional diapers. Embodiments are contemplated where the outer
cover 24 is stretchable along one direction (e.g. the lateral, the
transverse direction, or any other direction). In these
embodiments, the waist and/or leg perimeters can similarly be
force-decoupled from the anchoring system 42.
[0175] The outer cover, in some embodiments, can be impervious to
liquids (e.g., urine) and manufactured from a thin plastic film or
a nonwoven web, although other flexible liquid impervious materials
which are compliant and will readily conform to the general shape
and contours of the human body can also be used. Additionally, in
some embodiments, the outer cover 24 may comprise a laminated
structure.
[0176] The outer cover may be generally positioned such that it can
be at least a portion of the garment-facing surface of the diaper.
The outer cover can prevent the exudates absorbed and contained
within the diaper from soiling articles that can contact the
diaper, such as bed sheets and undergarments, in some embodiments.
Suitable outer cover 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. In various
embodiments, the outer cover can include an inelastic nonwoven. The
outer cover can be a thermoplastic film having a thickness of from
about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mils). Another
example of a suitable film which can be utilized in the outer cover
24 includes a 0.5-1.0 mil (0.0005-0.001'') thick Vistamaxx
(elastomeric polypropylene from ExxonMobil). In some embodiments,
elastomeric polypropylene based compositions are disclosed in WO
2005/052052 to ExxonMobil and in WO 2005/097031 to Procter &
Gamble. The elastomeric composition may also include fillers like
titanium dioxide for improving opacity and calcium carbonate for
breathability. The elastomeric polypropylenes may also be blended
with styrenic block copolymers, semicrystalline polyolefins or
sub-micron inorganic particles.
[0177] In some embodiments, the outer cover 24 may comprise an
elastic nonwoven. In some embodiments, the outer cover 24 may
comprise a laminate including an elastic nonwoven and a plastic
film, for example, polyethylene film. In some embodiments, the
outer cover 24 may comprise a laminate including an elastic film
and a non-elastic nonwoven. In some embodiments, the outer cover 24
may comprise a laminate including printed elastics. In some
embodiments, the outer cover 24 may comprise a laminate including
an elastic in the form of a scrim-like structure or a crosshatch
pattern that is joined between two layers of a nonwoven or between
a nonwoven and a breathable film (e.g. polyethylene film), etc.
[0178] The elastomeric film examples provided above can be
laminated to at least one layer of non-elastomeric or extensible
nonwoven using spiral glue. Additionally, this laminate can be
incrementally stretched in a machine direction and then in a cross
machine direction thereby forming a biaxially stretchable elastic
laminate. A suitable example of a nonwoven which can be utilized in
the outer cover 24 includes DAPP. A suitable DAPP nonwoven is sold
under the designation Softspan 200 available from BBA Fiberweb,
Brentwood Tenn. In some embodiments the DAPP can be joined to an
elastic element, e.g. elastomeric scrim and joined to a
polyethylene film. In some embodiments, the DAPP can be joined to
an elastic element, e.g. elastomeric scrim and joined to another
DAPP nonwoven.
[0179] Outer cover laminates, such as those described above,
wherein the elastomeric component is combined with another web in a
relaxed, unstretched state, are referred to in the art as
"zero-strain laminates". While in some embodiments, the zero-strain
laminate may be inherently stretchable in a virgin state, the
stretch properties of these materials are usually released or
improved by mechanical activation, or incremental stretching, such
as ring rolling or SELFing. Alternatively, pre-stretched laminate
materials may also be employed as outer cover materials in the
present invention. Pre-stretched elastomeric outer covers are
formed by applying an elastomeric material, e.g., strands or films,
to a substrate while the elastomeric material is in a prestrained
state, and subsequently allowing the laminate to relax and
contract. Pre-stretched biaxially stretchable outer cover materials
may be formed by applying pre-tensioned elastomeric elements in at
least two different directions, preferably, but not necessarily,
aligned with the longitudinal and lateral axes of the article. In
certain embodiments, outer covers of the present invention may
include both zero-strain and pre-stretched elastomers. For example,
a pre-tensioned elastomeric element may be affixed to a zero-strain
elastomeric laminate either parallel to the zero strain laminate's
primary direction of stretch or at an angle thereto.
[0180] In some embodiments, the outer cover 24 may comprise an
elastomeric layer which includes an elastomeric adhesive, e.g. a
hot melt pressure sensitive adhesive. In these embodiments,
additional adhesive may not be needed to bond the layers of the
laminate together. However, if the elastomeric material does not
have good adhesive properties, additional adhesive may be
utilized.
[0181] In some embodiments, the outer cover 24 may have a low force
at a specific elongation as measured by the Hysteresis Test (50%
Maximum Strain). Since the outer cover can have different stretch
properties in different directions, stretch properties in the
Hysteresis Test are measured in the longitudinal direction (machine
direction), lateral direction (cross machine direction) and in a
direction that is parallel to the length direction of the anchoring
band. In some embodiments, the outer cover 24 may have a first
cycle force less than about 20 gm/cm at 15% strain. In some
embodiments, the outer cover 24 may have a first cycle force less
than about 15 gm/cm at 15% strain. In some embodiments, the outer
cover 24 may have a first cycle force less than about 10 gm/cm at
15% strain.
[0182] Additionally, in some embodiments, the outer cover 24 may
also have a percentage set (as measured by the Hysteresis Test)
which is less than about 40% after about a 50% load Hysteresis
Test. In some embodiments, the outer cover 24 may have a percentage
set which is less than about 30% or in some embodiments, less than
about 15%.
[0183] In some embodiments, the outer cover 24 may be sufficiently
breathable. For example, in some embodiments, the outer cover 24
can be constructed to be permeable to at least water vapor and can
have a moisture vapor transmission rate (MVTR) of at least 1000
g/m.sup.2/24 hr., preferably at least 1500 g/m.sup.2/24 hr., more
preferably at least 2000 g/m.sup.2/24 hr., and even more preferably
at least 3000 g/m.sup.2/24 hr. In other embodiments, the outer
cover has an MVTR of at least about 7000 g/m.sup.2/24 hr. In some
embodiments, the outer cover 24 may have a moisture vapor
transmission rate of from about 1000 to about 8000 g/m.sup.2/24 hr.
or any individual number within the range. Some breathable
backsheet materials are described in greater detail in PCT
Application No. WO 95/16746; U.S. Pat. No. 5,938,648; U.S. Pat. No.
5,865,823; and U.S. Pat. No. 5,571,096. Other suitable exemplary
materials and a suitable test method for measuring the MVTR is
described in U.S. Pat. No. 6,448,467. Additionally, in some
embodiments, the outer cover 24 may comprise underwear-like
texture/aesthetics. One aspect of underwear like aesthetics is
gloss (as measured according to ASTM D2457-97) to give a pleasing
mate look (not plastic like). A gloss value of 7 gloss units or
less has been found desirable. Embossing and/or matte finishing
improves the outer covers gloss.
[0184] The outer cover 24, in some embodiments, may have sufficient
opacity such that exudates discharged into a core assembly 23
cannot be readily perceived from a vantage point external to the
diaper 20. Also, the outer cover may have sufficient opacity to
prevent the skin from being seen in the non-core areas of the
diaper. In order to increase the opacity of biaxially stretchable
outer cover elastic nonwovens, in some embodiments, at least one
meltblown may be incorporated into the spunbond web. The meltblown
layer may consist of nano-fibers. The meltblown layer may have a
basis weight of between about 1 gsm and about 20 gsm or any
individual number within the range. In some embodiments the
meltblown layer may have a basis weight of between about 4 gsm and
about 15 gsm and may comprise various combinations of elastomeric
and plastic polymeric resins. Higher elastomeric content may be
preferred when higher depths of activation (incremental stretching)
are required and/or when lower permanent set values in the outer
cover are desired. Elastomeric and plastic polyolefin combinations
may utilized in some embodiments to optimize the cost/performance
balance. In some embodiments, the elastomeric component may
comprise a very low crystallinity polypropylene grade such as those
commercialized by ExxonMobil under the tradename Vistamaxx.
Additionally, the elastic nonwoven structure may also include
another spunbond layer that does not provide significant elastic
recovery, yet possesses sufficient extensibility to survive the
activation process. Some suitable examples of such extensible
spunbond nonwoven layers are disclosed in WO 2005/073308 and WO
2005/073309.
[0185] Other exemplary breathable materials can include materials
such as woven webs, nonwoven webs, polymeric films such as
thermoplastic films of polyethylene or polypropylene, 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.
An exemplary, suitable outer cover is disclosed in U.S. Pat. No.
6,107,537.
[0186] All or a portion of the outer cover can be ring-rolled and
thus rendered highly extensible as described in U.S. Pat. No.
5,366,782 (issued Nov. 22, 1994 to Curro, et al). Specifically, a
ring-rolling apparatus includes opposing rolls having intermeshing
teeth that incrementally stretch and thereby plastically deform the
material forming outer cover (or a portion thereof) thereby
rendering the outer cover extensible in the ring-rolled regions. In
some embodiments, the outer cover can be ring-rolled in a portion
of at least one of the front or back waist regions while other
regions may comprise a structured elastic-like formed web material
or virgin or unactivated regions. Similarly, the chassis can be
ring-rolled across the entire width in one or both of the waist
regions or alternatively can be ring-rolled over only a portion of
the chassis width. Ring rolling can be performed in one or multiple
directions. For example, to make a biaxial stretchable outer cover,
the nonwoven-elastic laminate can be first activated in, say, the
lateral direction, and then in the longitudinal direction.
Alternatively, the nonwoven-elastic laminate may be activated in
any two directions aligned with, or at angles to, the longitudinal
and/or lateral axes of the article. For example, the laminate may
be activated plus and minus 45 degrees from the longitudinal axis.
Alternatively, the laminate may be activated at plus 60 and minus
30 degrees from the longitudinal axis.
[0187] Alternatively, the outer cover can comprise a structural
elastic-like film (SELF) web that is stretchable along one or more
of the longitudinal and lateral axes 200 and 210 (in FIG. 13A).
SELF webs suitable for the present invention are more completely
described in the commonly assigned U.S. Pat. No. 5,518,801 entitled
"Web Materials Exhibiting Elastic-Like Behavior" issued to Chappell
et al. on May 21, 1996.
[0188] Other suitable materials and/or manufacturing techniques can
be used to provide a suitable outer cover including, but not
limited to, surface treatments, particular film selections and
processing, particular filament selections and processing, etc. The
outer cover can be embossed and/or matte finished to provide a more
clothlike appearance.
[0189] As described above, the biaxial stretchable outer cover, in
some embodiments, has a low force, recoverable stretch (for
instance, less than about 15 g/cm at a strain of 50%), similar to a
cotton underwear. Such an outer cover can be made in several ways
(e.g. via elastomeric nonwovens, printed elastics, spraying, and
lamination). Nonwovens that predominantly have elastomeric fibers
or filaments have a rubbery feel and are generally not desired by
consumers. Since the stretchability of the outer cover occurs at
low forces, it is possible to use a blend of elastomeric, e.g.,
very low crystallinity elastomeric polypropylene, and plastic,
e.g., polypropylene, filaments. Exemplary structures are discussed
in WO 2005/065680; WO 2005/052052; and WO 2005/097031. Advantages
to using such a blend include the fact that the thermoplastic
fibers help improve the feel of the outer cover 124 to the
wearer/user. Additionally such a blend provides a force limit, as
the nonwoven is incrementally stretched in order to release the
stretch properties. An alternative method for fabricating the
biaxially stretchable outer cover is to provide an elastomeric
nonwoven structure that comprises bicomponent fibers having an
elastomeric core and a thermoplastic sheath. Exemplary structures
are discussed in U.S. Pat. No. 6,225,243; U.S. Pat. No. 5,470,639;
and U.S. Pat. No. 5,997,989. This nonwoven may also have improved
feel.
[0190] In both the above methods, the elastomeric nonwoven can be
incrementally stretched to release the stretch. The nonwoven
biaxial stretchable outer cover can be carded, spunbond, SMS
(sponbond-meltblown-spunbond), or otherwise fabricated. The fine
fibers of the meltblown layer in the SMS structure provide enhanced
opacity, a desirable feature in outer covers. Replacing the
meltblown layer with nano fibers may further increase the opacity
of the outer cover.
[0191] The biaxially stretchable outer cover can also be made by
elastomer printing, spraying, slot coating, meltblown or film
lamination. Printing includes gravure, flexographic, letterpress,
screen, digital, or the like. Some suitable examples of printing
are described in U.S. Application Publication No. 2003/0088220A1;
U.S. Application Publication No. US 2003/0088228A1; U.S.
Application Publication No. 2003/0091807A1; U.S. Application
Publication No. 2004/0193133A1; U.S. Application Publication No.
2004/0222553A1; U.S. Application Publication No. 2005/0214461A1;
U.S. Application Publication No. 2003/0084996A1; U.S. Application
Publication No. 2003/0084996A1; U.S. Application Publication No.
2003/0087059A1; U.S. Application Publication No. 2003/0087098A1;
U.S. Pat. No. 6,875,710; and U.S. Pat. No. 6,942,894.
[0192] Spraying includes standard techniques for hot melt adhesive
spraying, e.g. spiral, zig-zag pattern, ITW/s Omega pattern,
meltblown, etc. An elastomeric film can be bonded to a nonwoven by
extrusion or adhesive lamination. Preferably, the elastomeric film
is breathable.
[0193] In accordance with certain aspects of the invention, various
materials can be used to provide a biaxially stretchable outer
cover in accordance with various embodiments of the present
invention. When constructing the biaxially stretchable outer cover,
various desirable features include the following: [0194] Mechanical
properties (as expressed in terms as measured in a Hysteresis test)
during multiple medium-strain stretch-recovery cycles; As well as
the ability to survive high-strain-rate medium depth of engagement
Mechanical Activation in both machine direction and cross direction
without pinhole); [0195] Durability (low Fuzz, high Ultimate
Strength); [0196] Visuals (white color, high opacity,
cotton-ribbon-like texture, printable, gloss); [0197] Liquid
Barrier properties in some embodiments (absence of pinholes or any
other signs that could signal the possibility of outer cover
leakage); and [0198] Low cost.
[0199] Variations in specific targets may be found depending upon
whether the design is for a pant or a taped diaper. For instance,
as is described in more detail below, one embodiment of a taped
diaper design has an integrated anchoring system built into the
biaxially stretchable outer cover which is created by differential
activation (an area of the biaxially stretchable outer cover is
intentionally left un-activated). Therefore, the development of the
outer cover material takes into account performance targets for
both pre- and post-activation states. The pant design may have more
stringent upper limits for the CD stretch load of the biaxially
stretchable outer cover in order to maintain easy diaper
application.
[0200] The biaxially stretchable outer cover preferably has
mechanical and/or elastic properties as described herein, as well
as the ability to survive high-strain-rate mechanical activation
(i.e., incremental stretching) in both the longitudinal and lateral
directions without pinhole formation. Laminates which exhibit
reduced pinholes from activation are described in U.S. application
Ser. No. 11/361,918, entitled, "Method of Making Laminate
Structures for Mechanical Activation", filed on Feb. 24, 2006, on
behalf of Anderson et al. Additionally, the outer covers of the
present invention preferably have a low tendency to fuzz, have high
opacity, and are printable via printing processes common to the
art.
[0201] The biaxially stretchable outer cover may be formed from any
elastic or extensible web material or composite as known in the
art. The biaxially stretchable outer cover may comprise an elastic
nonwoven, an elastic nonwoven laminated with an extensible and/or
elastic film or scrim, an extensible nonwoven laminated with an
elastic film or scrim, a web comprising an elastomer pattern
printed on an elastic and/or extensible nonwoven, variants of any
of the preceding materials at least a portion of which is
mechanically pre-strained, or any other elastic or extensible
materials as known in the art.
[0202] In some embodiments of the present invention, the biaxially
stretchable outer cover comprises only an elastic nonwoven. In
these embodiments the total basis weight of the outer cover may be
less than about 50 gsm, preferably less than about 40 gsm, and more
preferably less than about 35 gsm. The outer cover material may
comprise a spunbond fabric and be produced under conditions that
promote optimal bond strength in order to provide sufficient
strength and durability to the outer cover. Elastic nonwoven outer
covers include at least one elastomeric material in a sufficient
amount to provide a minimal desirable amount of recovery. Examples
of suitable spunbond nonwovens are described in U.S. Pat. Nos.
5,470,639 and 5,997,989. In some embodiments of the present
invention, the elastic nonwoven comprises elastic/plastic
bicomponent fibers, examples of which are described in U.S. Pat.
No. 6,225,243 and WO2006/017674, to provide the outer cover
material with better hand/feel properties and improved
spinnability. The outer cover material may also comprise webs,
i.e., as disclosed in WO 2005/065680, formed of mixed elastic
fibers (e.g., thermoplastic polyurethane elastomer) and plastic
(e.g., polyolefins such as polypropylene) fibers, said nonwovens
having good elastic recovery and tactile properties after being
subjected to mechanical activation, such as Vistamax.TM. available
from Exxon Another suitable elastic component is very low
crystallinity elastomeric polypropylene. Other suitable examples of
spunbond elastic nonwovens are disclosed in WO 2005/052052 and WO
2005/097031. In embodiments wherein the elastic nonwoven outer
cover comprises mixtures or composites of both elastic and plastic
materials, the ratio of the elastic to plastic components can be
tailored to provide a desirable balance of both stretch/recovery
characteristics and strength/toughness requirements. High toughness
is desirable to maximize the ability of the web to survive
mechanical activation in both the longitudinal and lateral
directions.
[0203] Other exemplary materials suitable for the outer cover are
disclosed in U.S. Pat. No. 6,896,843; U.S. Pat. No. 6,225,243; U.S.
Pat. No. 5,997,989; U.S. Pat. No. 5,952,252; U.S. Pat. No.
5,695,849; U.S. Pat. No. 5,470,639; U.S. Pat. No. 5,405,682; WO
2005/052052; WO 2004/065680; WO 2006/017674; US 2004/0132374; US
2004/0110442; US 2003/0162458; U.S. Pat. No. 6,811,871; U.S. Pat.
No. 6,103,647; U.S. Pat. No. 5,635,290; and U.S. Pat. No.
5,540,976.
[0204] In some embodiments of the present invention, the biaxially
stretchable outer cover may comprise a laminate of elastic
nonwovens, such as those described in the preceding section, and an
extensible film. In this embodiment, a thin extensible polyolefin
film layer is laminated onto the elastic nonwoven described above.
Although higher basis weights are contemplated in certain
embodiments, the basis weight of the film may be no more than about
22 gsm, preferably no more than about 20 gsm, and more preferably
no more than about 18 gsm in order to minimize the cost of the
laminate. The film may be combined with the elastomeric nonwoven
via adhesive lamination, extrusion lamination, or any other
suitable means of combining webs as known in the art. The film may
preferably be extensible in both longitudinal and lateral
directions and able to survive a mechanical activation (i.e.,
incremental stretching) process without pinhole formation over the
relevant range of activation strains. The film may preferably be
breathable, as discussed previously, whether the breathability
originates from activation-induced micro-porosity or virtually
invisible pinholes. The film may be either extensible, i.e.
plastic, or it may be plastoelastic and exhibit partial recovery,
hence participating in the elastic recovery process. Examples of
"plastic" films include films comprising standard filled
polyethylene resins, e.g. those disclosed in WO 2006/017518.
Examples of the use of plastoelastic film formulations are
disclosed in WO 2005/097031. The presence of the film laminated
onto the stretch NW contributes to create highly desirable visuals
such as high opacity and high texture without the need for
incorporating the type of melt-blown layer described above.
Alternatively, the film may comprise high-performance elastomers
such as Kraton-based elastomers. Further examples of elastic
nonwoven/extensible film laminates suitable for the present
invention are disclosed in WO 2005/017518; US 2005/0124952; U.S.
Pat. No. 6,811,865; U.S. Pat. No. 6,623,837; and U.S. Pat. No.
6,096,668.
[0205] In some embodiments, the film can be the component that
exhibits at least partial recovery upon stretching. The nonwoven
may be an extensible spunbond or a necked/gathered spunbond of the
types described above. As described above, in some embodiments, the
basis weight of the film may be no more than about 22 gsm,
preferably no more than about than 20 gsm, more preferably no more
than about 18 gsm in order to minimize the cost of the laminate as
well as minimize the force required to stretch the BSOC up to 50%
strain. The film may be combined with the nonwoven either via
adhesive lamination or via extrusion lamination. The film should be
selected as described above such as to survive an incremental
stretching process without pinhole formation over the relevant
range of activation strains. The film may be breathable as
described herein. An example of a filled elastic polyethylene blend
film is disclosed in U.S. Pat. No. 6,909,028. Preferred elastomeric
polypropylene-based compositions are disclosed in WO 2005/052052
and in WO 2005/097031. Blends of elastomeric polypropylenes with
either styrenic block-copolymers, semicrystalline polyolefins or
sub-micron inorganic particles can be used to enhance the
stress-strain and hysteresis properties of the laminate. For
example, decreasing the force required to extend the BSOC and
improving elastic recovery is achievable by adding styrenic block
copolymers into a Vistamaxx polymer. Micro-porous breathable
elastic films based on calcium carbonate-filled elastomeric
polypropylene-based compositions are also contemplated. The film
may additionally increase the opacity of the BSOC and potentially
eliminate or reduce the need for the presence of a meltblown layer
in the nonwoven.
[0206] Exemplary BSOC materials related to these embodiments are
disclosed in U.S. Pat. No. 6,909,028; U.S. Pat. No. 6,680,265; U.S.
Pat. No. 6,680,265; U.S. Pat. No. 6,015,764; U.S. Pat. No.
5,947,944; WO 2004/060669; U.S. Pat. No. 6,627,564; U.S. Pat. No.
6,479,154; U.S. Pat. No. 6,465,073; U.S. Pat. No. 6,313,372; U.S.
Pat. No. 6,001,460; WO 2004/060652; and U.S. Pat. No.
6,849,324.
[0207] In some embodiments of the present invention, an elastomer
may be printed onto a nonwoven, film, or laminate, including those
described above, to form a BSOC. The elastomer may be printed as a
film or in a pattern. If printed as a pattern, the pattern may be
relatively homogeneous over the area of the outer cover, i.e., in a
net-like or dot pattern, or may comprise regions of relatively
higher or lower basis weight wherein the elastomeric component is
been applied onto at least one region of an extensible fibrous
substrate to provide stretch properties to a targeted region of the
substrate (i.e., after selective incremental stretching). The
elastomer may be transferred onto the fibrous substrate through a
process such as gravure printing which provides a great deal of
flexibility relative to the amount of elastomer deposited as well
as the type of patterns that can be achieved. Details on these
embodiments, and further examples of suitable materials and
patterns, are disclosed in US 2005/0214461, WO 2005/097358, and WO
2005/097512. Polyolefins blends and polyolefins/styrenic block
copolymers such as those disclosed above and tailored to possess
the desired rheological characteristics for adequate deposition via
gravure printing represent preferred compositions for the present
invention. Other exemplary materials and processes are disclosed in
US 2005/0106980; U.S. Pat. No. 6,579,274; U.S. Pat. No. 6,503,236;
and U.S. Pat. No. 6,264,641.
[0208] Regardless of the composition of the biaxially stretchable
outer cover, the outer cover material can be mechanically activated
in both the longitudinal and lateral directions via any of the
processes described herein in order to increase the strain range
over which the web exhibits stretch/recovery properties, impart the
desirable tactile/aesthetic properties to the material (e.g., a
cotton-like texture), and in some embodiments create the higher
modulus components of the anchoring system, such as linkages or
anchoring bands. Mechanical activation processes include
ring-rolling, SELFing, and other means of incrementally stretching
webs as known in the art. In some embodiments it may be desirable
to (selectively) over-bond (parts of) the outer cover (at areas not
activated) to further increase the mechanical strength of (parts
of) the outer cover.
[0209] The outer covers of the present invention may additionally
comprise graphics printed on the outside or inside surface of one
of the outer cover or waist/leg band components or printed on an
underlying component of the article. The graphics may be
decorative, educational, entertaining, or instructional. Multiple
topically related or unrelated graphics may be employed. The
graphics may be formed such that they are most clear or legible
when the printed substrate is in a relaxed condition or when the
printed substrate is in an extended condition. Alternatively, some
of the graphics may be most clear or legible when the printed
substrate is in a relaxed condition, while others are most
clear/legible when the printed substrate is in an extended
condition. In certain embodiments, the graphics comprise active
graphics, i.e., graphics which change based on environmental
conditions such as elapsed time, humidity, temperature, wetness,
etc. Active graphics may be topically related to each other so as
to portray and event or action (e.g., a fish appears or disappears
from a character's fishing line).
Core Assembly and Other Components
[0210] Referring back to FIG. 1B, in some embodiments, the core
assembly 23 may include a topsheet 22, a containment member 28, and
an absorbent core 26 disposed between the topsheet 22 and the
containment member 28. As shown, the core assembly 23, in some
embodiments, may form a bucket shape. The term "bucket-shaped"
derives from the appearance of a lateral cross section of the core
assembly 23 when the article is configured as it would be when
applied to a wearer. The bucket-shaped core assembly 23 represents
a substantially self-contained core assembly 23 as it may comprise
the topsheet 22, absorbent core elements, a containment member 28,
and leg cuffs 35, e.g. inner cuff or barrier leg cuffs. As will be
appreciated from the description below, it can be said that the
core assembly 23 is self-contained.
[0211] The core assemblies suitable for use in the absorbent
articles of the present invention are not limited to the "bucket
shaped" assemblies. For example, embodiments are contemplated where
the core assembly comprises an absorbent core, optionally a core
wrap, and optionally an acquisition/distribution system (see FIGS.
13A, 14A, 15A, 16, 17, 18, and 19A). One skilled in the art would
appreciate that the core assemblies described herein can be
utilized with any suitable anchoring system described herein. In
the non-bucket embodiments the core is sandwiched between the
topsheet and the outer cover. Preferably the core is (partially)
force decoupled from the topsheet and the outer cover, i.e. the
core can float.
[0212] As shown in FIG. 1B, in some embodiments, the containment
member 28 covers a garment-facing surface of the core 26, at least
in part, and extends laterally beyond the core 26. As shown, in
some embodiments, the laterally distal ends of containment member
28 can be connected to a spacing member 30, such as an elastic,
that biases a portion of the containment member 28 that is disposed
laterally outboard of the core 26 vertically away from the
body-facing surface of the chassis 21. In some embodiments, the
spacing members 30 may bias the laterally distal ends vertically
outwardly or vertically inwardly from longitudinal side edges of
the core 26.
[0213] Some examples of suitable spacing members 30 include
elastomeric films, elastomeric foams such as polyurethane foams or
cross-linked natural rubber foams; formed elastic scrim;
elastomeric films such as heat shrinkable elastic materials;
elastomeric film laminates such as a laminate of a heat-shrinkable
elastomeric film and a resilient member; and elastic strands made
from rubber, synthetic rubber, elastomeric polyurethane, or other
materials.
[0214] The laterally distal ends of the containment member 28 can
define a pair of opposing and longitudinally extending leg cuffs 35
that extend out from the inner-facing surface 50 of the diaper 20
to provide a seal against the wearer's body and improve containment
of liquids and other body exudates. Additionally, the containment
member 28 may comprise a central zone 1500 and a pair of barrier
zones 1510. The central zone 1500 is a portion of the containment
member 28 disposed adjacent (but not necessarily in face-to-face
contact) to the garment-facing surface of the absorbent core 26. In
some embodiments, longitudinal boundary of the central zone 1500 is
coterminous with the longitudinal edges of the absorbent core 26.
However, in other embodiments, the longitudinal boundary of the
central zone 1500 may be inboard or outboard of the longitudinal
edges of the absorbent core 26. The barrier zones 1510 are portions
of the containment member 28 disposed between the central zone 1500
and the distal ends of the containment member 28. The barrier zones
1510 serve as barrier leg cuffs 35 for the absorbent assembly 23.
In other words, by extending away from the body-facing surface of
the chassis 21, the barrier zones 1510 can provide a physical
barrier to the free flow of exudates and provides a structure to
contain the exudates within the absorbent assembly 23.
[0215] In some embodiments, the containment member 28 may
additionally provide a forming layer on which liquid absorbent
material can be deposited during manufacture of the core assembly
23 and is generally an air permeable material. The containment
member 28 can be a hydrophobic material and can be rendered liquid
impermeable, e.g., in the central zone 1500 and/or barrier zone
1510 of the containment member 28, by coating at least the
garment-facing or the wearer-facing side, or both, of the central
zone 1500 and/or the barrier zones 1510 of the containment member
28 with an impermeable material. The impermeable material may
comprise a breathable or non-breathable film or may comprise an
in-situ formed barrier layer such as a hydrophobic coating. The
hydrophobic coating may comprise any suitable hydrophobic material
known in the art. For example, the hydrophobic coating may comprise
a wax composition, a hydrophobic skin care composition, or
materials with similar properties, which is applied to the
containment member 28 in a molten form and subsequently cooled to
form a continuous coating. If at least the central zone 1500 of the
containment member 28 is liquid impermeable, the outer cover 24 can
be constructed as a liquid permeable member.
[0216] If the containment member 28 acts both as a forming
substrate for at least a portion of the absorbent core 26 and as a
leg cuff material, its properties can be properly balanced. For
example, in some embodiments, the containment member 28 can be air
permeable in a portion of the central zone 1500 and/or the barrier
zones 1510 which may allow sufficient control over the process of
absorbent material deposition thereon, Subsequent to the deposition
of the absorbent material, the air permeability of the central zone
1500 may be decreased if desired. Additionally, the containment
member 28 may be sufficiently impermeable to liquids in barrier
zones 1510 to serve as a barrier cuff. Accordingly, in certain
embodiments, the central zone 1500 may exhibit an air permeability
of about 100 to 300 m.sup.3/m.sup.2/min at a pressure drop of 125
Pa, preferably around 120 to 200 m.sup.3/m.sup.2/min, as measured
according to the Air Permeability Test provided below. Conversely,
it is desirable that the barrier zone 1510 be liquid impermeable;
however, it is believed that the degree of air permeability
required in the central zone would harm liquid impermeability.
Therefore, the barrier zone 1510 may exhibit an air permeability
less than that of the central zone 1500. In certain embodiments,
the barrier zone 1510 exhibits an air permeability that is about
10%, about 20%, about 50%, about 75%, or about 100% less than the
air permeability of the central zone 1500.
[0217] The barrier zone 1510 may exhibit liquid impermeability for
barrier protection while maintaining air and vapor permeability for
wearer comfort. In certain embodiments, the barrier zone 1510
exhibits a hydrohead, as measured according to the Hydrostatic Head
(Hydrohead) Pressure Test provided below, of greater than about 10
mbar, 20 mbar, and 40 mbar.
[0218] In some embodiments, the constraints on the properties of
the base material of the containment member 28 may be relaxed by
treating a portion of the containment member material to enhance
its ability to perform either the core material deposition function
(i.e., increase air permeability) or the barrier cuff liquid
containment function (i.e., decrease liquid permeability). For
example, the central zone 1500 may be treated such that its air
permeability is increased, enabling it to better act as a core
material deposition substrate. Alternatively, the barrier zones
1510 may be treated to make them more liquid impermeable to enhance
their liquid barrier functionality as barrier cuffs.
[0219] Any suitable treatment known in the art can be utilized to
increase air permeability and/or decrease liquid permeability.
Examples of some suitable treatments include chemical, mechanical,
thermal, and other surface energy modifying treatments, such as
plasma treatment (e.g., via corona discharge, etc.). In one
example, the treatment may reduce liquid permeability by decreasing
the surface energy of the material, reducing the pore size
distribution in the web, or occluding the web with a liquid
impermeable layer. In another example, the treatment may increase
air permeability by increasing the porosity of the web by
mechanically inducing hole formation and/or enlargement via
aperturing (e.g., pin aperturing, laser aperturing, etc.) or
stretching the web (e.g., via tentering, or incremental stretching,
e.g. activation, ring-rolling, SELFing). In some embodiments, both
the central and barrier zones can be treated as described above. In
another example the central cone 1500 initially has high air
permeability, the absorbent material is deposited onto it
(requiring the high air permeability), and afterwards the central
zone 1500, and potentially zone 1510 are treated to make it less
liquid permeable.
[0220] Some examples of suitable chemical treatments include
application of hydrophobic compositions such as hydrophobic skin
care compositions, silicones, or any other low surface energy
composition as is known in the art. Some examples of suitable
mechanical treatments include tentering, spreading (i.e., in the
lateral direction via a spreading bar), incrementally stretching,
e.g. ringrolling and SELFing, abrading, over-stretching (i.e., in
the longitudinal direction), aperturing (i.e., via mechanical means
such as pins or dies, lasers, water jets, air jets, and the like),
puncturing, hole punching, slitting, microSELFing, and other
mechanical treatments as known in the art. Some examples of
suitable thermal treatments include heated smooth roll calendaring
and other thermal means, such as hot air treatments, lasers,
radiofrequency heating, and ultrasonics, to at least partially melt
portions of the material structure (e.g., fibers) to reduce average
pore size. In some embodiments, thermal treatments may be enhanced
in embodiments wherein the barrier layer comprises a
multi-component material, such as a nonwoven comprising bicomponent
fibers wherein one of the components has a lower melting point than
the other. Other suitable treatments for the central zone 1500, the
barrier zones 1510 and suitable materials and configurations for
the containment member 28 are discussed in a co-pending patent
application entitled "Absorbent Article Having a Multifunctional
Containment Member", filed on behalf of Roe et al. on Jun. 7, 2006,
having an attorney docket number of 10435P.
[0221] In some embodiments, the containment member 28 can be a
single continuous material in its lateral dimension. In some
embodiments, however, the containment member 28 can comprise two or
more separate materials that overlap and/or abut along their
lateral edges and are combined or bonded to form a composite web.
For example, a web of a first material may form the central zone
1500 of the containment member 28, while a web of a second material
may form each of the barrier zones 1510 of the containment member
28. Or, a web of a second material may form zone 1500 (e.g. a
film), while a web of a first material (e.g. a nonwoven) may form
zones 1500 and 1510. While the first and second materials may be
identical or have similar properties, it may be preferable that
they have properties specific to their intended functions. For
example, per the above description, the first material may comprise
a highly air permeable material while the second material may
comprise a highly liquid impermeable material. The webs may be
bonded via any know method as known in the art as long as the
functionality of the central and barrier zones is minimally
impacted. The webs may be bonded together along their entire
lengths.
[0222] The containment member 28 may comprise a woven web, a
nonwoven web, an apertured film, and a composite or laminate of any
of the aforementioned materials. The containment member 28 may
comprise a nonwoven, fibrous web that comprises synthetic and/or
natural fibers. In certain embodiments, the containment member 28
is an air permeable nonwoven web such as described in U.S. Pat. No.
4,888,231.
[0223] As shown in FIG. 1B, in some embodiments, a core cover 29
can be disposed on a wearer-facing surface of the core 26 and may
help immobilize the liquid absorbent material of the absorbent core
26. The core cover 29 may generally be a liquid pervious material,
such as a nonwoven or tissue. In some embodiments, the core
assembly 23 may further comprise the topsheet 22 which can be
disposed adjacent a body-facing surface of the core cover 29.
[0224] The absorbent core 26 may comprise a wide variety of
liquid-absorbent materials commonly used in disposable diapers and
other absorbent articles. The absorbent core can comprise any
absorbent material that is generally compressible, conformable,
non-irritating to the wearer's skin, and capable of absorbing and
retaining liquids such as urine and other certain body exudates.
Examples of suitable absorbent materials include comminuted wood
pulp (e.g., air felt creped cellulose wadding, fluff); melt blown
polymers including co-form; chemically stiffened, modified or
cross-linked cellulosic fibers; wraps and tissue, including wraps
and tissue laminates; absorbent foams; absorbent sponges;
superabsorbent polymers (such as superabsorbent fibers), absorbent
gelling materials, mineral microfibers, and Parez.TM. bonded wet
laid fibers, or any other known absorbent material or combinations
of materials. Examples of some combinations of suitable absorbent
materials are fluff with absorbent gelling materials and/or
superabsorbent polymers, and absorbent gelling materials and
superabsorbent fibers etc. The absorbent core can further comprise
minor amounts (typically less than 20% or less than about 10%) of
non-liquid absorbent materials, such as adhesives, waxes, oils, and
combinations thereof.
[0225] Examples of other suitable absorbent core constructions are
described in U.S. Publication No. 2004/0167486 to Busam et al. The
absorbent core of the aforementioned publication uses no or minimal
amounts of absorbent fibrous material within the core. Generally,
the absorbent core may include no more than about 20% weight
percent of absorbent fibrous material (i.e., [weight of fibrous
material/total weight of the absorbent core].times.100).
[0226] In certain embodiments the absorbent core may comprise an
insert that may be removable from the article and replaceable with
a fresh, unused insert. The insert may be applied to the wearer
facing surface of the article and held in place via friction,
overlapping portions of the article, or by a fastener element such
as adhesive or a hook/loop fastening element. Alternatively, the
insert may be inserted through an opening in the outer surface of
the article or at the waist region such that the absorbent capacity
of the article may be replenished without removing the article from
the wearer. The article may also comprise addition absorbent core
elements which may or may not be replaceable.
[0227] Regardless of its construction and composition, the
absorbent core preferably contributes to an underwear-like
appearance of the article. Since most underwear have no absorbent
core, in certain embodiments, the cores of the present invention
may be very thin. In these non-limiting embodiments the absorbent
core may have a thickness when dry of no more than about 2 mm,
preferably no more than about 1 mm, and generally within the range
of 0.5 and 1.5 mm. It should be noted that the calliper of the core
may vary across its area. At least a portion of the core should
have the thinness described above; preferably at least about 25% of
the total area of the core, more preferably at least about 50% of
the total area of the core, and most preferably at least about 75%
of the total area of the core.
[0228] Since underwear-likeness is a key aspect of discretion, and
since discretion is relatively more important for older wearers
(i.e., bedwetting school age children, adults, etc.), the cores of
the present invention should have relatively high urine capacities.
In embodiments of the present invention intended for wearers older
than about 4 years of age (i.e., beyond typical toilet training
age), the cores preferably have a capacity of at least about 500
grams of synthetic urine, more preferably more than about 700 grams
of synthetic urine, and most preferably more than about 900 grams
of synthetic urine.
[0229] In some embodiments, the absorbent core may comprise a fluid
acquisition component which acquires fluid exudates and partitions
the exudates away from a wearer's body, a fluid distribution
component which distributes/redistributes fluid exudates points
away from the point of initial exudate loading, and/or a fluid
storage component which retains a majority of the fluid exudates on
a weight basis. In some embodiments of the present invention the
absorbent core may comprise, in addition to the storage layer and
the durable hydrophilic core wrap, an acquisition system, which
comprises an upper acquisition layer facing towards the wearer and
a lower acquisition layer. In one embodiment the upper acquisition
layer comprises a nonwoven fabric whereas the lower acquisition
layer comprises a mixture of chemically stiffened, twisted and
curled fibers, high surface area fibers and thermoplastic binding
fibers. In other embodiments, both acquisition layers are provided
from a non-woven material, which can be hydrophilic. The
acquisition layer is in direct contact with the storage layer.
Furthermore, the storage layer or parts thereof, such as the upper
acquisition layer, can optionally be coated with a hydrophilicity
boosting composition.
[0230] An example of a suitable absorbent core comprising an
acquisition layer, a distribution layer, and/or a storage layer is
described in U.S. Pat. No. 6,013,589. Other exemplary absorbent
core configurations are discussed in U.S. Patent Application
Publication No. 2003/0225382A1; U.S. application Ser. No.
11/329,797, entitled, "End Seal For an Absorbent Core", filed on
Jan. 11, 2006; and U.S. application Ser. No. 11/329,796, entitled,
"Sealed Core For An Absorbent Article", filed on Jan. 11, 2006. Yet
other exemplary absorbent structures for use as the absorbent
assemblies are described in U.S. Pat. No. 4,834,735, entitled "High
Density Absorbent Members Having Lower Density and Lower Basis
Weight Acquisition Zones", issued to Alemany et al. on May 30,
1989; and U.S. Pat. No. 5,625,222 entitled "Absorbent Foam
Materials For Aqueous Fluids Made From high Internal Phase
Emulsions Having Very High Water-To-Oil Ratios" issued to DesMarais
et al. on Jul. 22, 1997.
[0231] The components of the core assembly 23 can be joined as
described via any suitable adhesive or cohesive. While adhesive or
cohesive can be used to connect various absorbent article
components as illustrated and described herein, one having ordinary
skill in the art will appreciate that any suitable alternative
attachment mechanism can facilitate such connections. Examples of
suitable alternatives include, but are not limited to, thermal
bonds, RF (radio frequency) bonds, pressure bonds, ultrasonic
bonds, welds, stitching, and the like. Any of the aforementioned
layers of the core assembly 23 can comprise a single material or
may comprise a laminate or other combination of two or more
materials.
[0232] In conventional absorbent articles, cores are typically not
stretchable. Because the outer cover can be biaxially stretchable,
it may be beneficial to render the core stretchable, at least in
the longitudinal direction. This will allow the product length to
be reduced, while still being able to fit all the wearers in a
given size. The core can be rendered stretchable in one of several
ways. For example, the components that make up the core could be
inherently stretchable, e.g. stretchable nonwovens. As another
example, the core may comprise folds in the longitudinal direction,
which unfold when the product is stretched. As another example, the
core may comprise two separate parts, a front half and a back half,
with some overlap in the crotch region, the first waist region, or
the second waist region. As the diaper stretches, the two parts of
the core slide past each other, decreasing the degree of overlap.
It should be appreciated, however, that the core need not be
stretchable for an absorbent article to suitably conform to the
wearer's body in accordance with the principles of the present
invention.
[0233] In certain embodiments, the chassis 21 provides the main
structure of the diaper 20 with other features added to form the
composite diaper structure. While the topsheet 22, the outer cover
24, and the core assembly 23 can be assembled in a variety of
well-known configurations, certain 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. Topsheet
22, outer cover 24, and absorbent core 26 are discussed in more
detail below.
[0234] Furthermore, while the topsheet 22, the outer cover 24, and
the absorbent core 26 can include many different materials and can
be assembled in a variety of well known configurations, suitable
diaper materials and configurations are described generally in U.S.
Pat. No. 3,860,003 entitled "Contractible Side Portions for
Disposable Diaper" which issued to Kenneth B. Buell on Jan. 14,
1975; and U.S. Pat. No. 5,151,092 issued to Buell on Sep. 9, 1992;
and U.S. Pat. No. 5,221,274 issued to Buell on Jun. 22, 1993.
[0235] As described herein, the topsheet 22 is generally a portion
of the diaper that can be positioned at least in partial contact or
close proximity to a wearer. Accordingly, the topsheet can be
supple, soft feeling, and non-irritating to a wearer's skin.
Generally, at least a portion of the topsheet is liquid pervious,
permitting liquids (e.g., urine) to readily penetrate through its
thickness. The topsheet can be made of a hydrophobic material to
isolate the wearer's skin from liquids contained in the absorbent
core. Suitable topsheets can 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. A suitable topsheet is available from BBA Fiberweb,
Brentwood, Tenn. as supplier code 055SLPV09U. Other examples of
suitable topsheets 22 are described in U.S. Pat. No. 3,929,135,
issued to Thompson on Dec. 30, 1975; U.S. Pat. No. 4,324,246 issued
to Mullane et al. on Apr. 13, 1982; U.S. Pat. No. 4,342,314 issued
to Radel et al on Aug. 3, 1982; U.S. Pat. No. 4,463,045 issued to
Ahr et al. on Jul. 31, 1984; and U.S. Pat. No. 5,006,394 issued to
Baird on Apr. 9, 1991. Other suitable examples of materials
suitable for use as a topsheet are described in U.S. Pat. No.
5,916,661; U.S. Pat. No. 6,680,422B2; U.S. Pat. No. 5,342,338; and
U.S. Patent Application Publication No. 2003/0021951A1.
[0236] In the various embodiments discussed above, the topsheet can
span the entire range from being completely non-stretchable to
being biaxially elastic. This covers extensibility in the lateral
direction, longitudinal direction, or both the lateral and
longitudinal directions, extensibility in one direction and
elasticity in the other direction, and elasticity in one or both
directions. In accordance with certain aspects of the invention,
particularly considering manufacturing costs, it may be desired to
confine all the elastic stretch (recoverable stretch) to just the
outer cover.
[0237] Alternatively, the topsheet can be rendered stretchable
(extensible or elastic) by any of the methods known in the art,
including incremental stretching, stretch bonding, neck bonding,
and the like. A non-stretchable topsheet can be made extensible in
the lateral direction during fabrication by incrementally
stretching in the lateral direction, maintaining enough
longitudinal tension in the web in order to prevent the web from
spreading out, and bonding the topsheet to the outer cover and core
of the diaper while the width of the web is maintained.
Extensibility or slack can be built into a non-elastic topsheet in
the longitudinal direction by pre-stretching a shorter, elastic
outer cover in the longitudinal direction to make it the same
length as the longer topsheet, bonding the two together at least in
some areas, and allowing the outer cover to retract. This produces
regions in the topsheet that are gathered in the longitudinal
direction, thus allowing the diaper to stretch up to the full
length of the topsheet without the topsheet offering any
significant resistance.
[0238] The topsheet can be rendered elastic using any of the
methods known in the art, including stretch bonding, neck bonding
incremental stretching, and the like. The preferred options for
making an elastic topsheet are similar to those used to make the
elastic outer cover.
[0239] The topsheet can be made stretchable in one direction or
biaxially stretchable by any of the methods known in the art. In
accordance with certain aspects of the present invention, the
topsheet can be rendered biaxially elastic. For example, the
topsheet could be an elastomeric nonwoven formed from a mixture of
elastomeric and non-elastomeric fibers/filaments. Incrementally
stretching the nonwoven releases the stretch properties. An
alternative approach would be printing an elastomeric composition
onto an extensible substrate, followed by incremental stretching if
desired. Yet another approach is to print an elastomeric
composition onto an elastomeric nonwoven or film.
[0240] Any portion of the topsheet can 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 can be fully or partially elasticized or
can be foreshortened so as to provide a void space between the
topsheet and the core. 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.
[0241] For example, the diaper may also include a waistband 43 (see
FIG. 1A) that can generally form at least a portion of the end edge
56 of the diaper 20. The waistband 43 is that portion or zone of
the diaper 20 which is intended to elastically expand and contract
to dynamically fit the wearer's waist, and that helps provide
improved fit and containment. The elastic waistband 43 can include
a segment positioned in the front waist region 36 and/or back waist
region 38, and can be discretely attached or an integral part of
the chassis 21. Examples of suitable waistbands include those
described in U.S. Pat. No. 4,515,595; U.S. Pat. No. 5,151,092; and
U.S. Pat. No. 5,221,274.
[0242] The diaper can also include a leg band or leg elastic that
helps provide improved fit and containment, as is appreciated by
one having ordinary skill in the art. The leg band is that portion
or zone of the diaper 20, which is intended to elastically expand
and contract to dynamically fit the wearer's leg. Leg elastics may
include several different embodiments for reducing the leakage of
body exudates in the leg regions. Leg elastics and contractible leg
openings are discussed in U.S. Pat. No. 3,860,003; U.S. Pat. No.
4,909,803; U.S. Pat. No. 4,695,278; and U.S. Pat. No.
4,795,454.
[0243] Alternatively, the waist and/or leg bands may comprise a
separate element discretely affixed to the inner or outer surface
of the article in proximity to the lateral or longitudinal edges of
the article. The separate element is preferably elastomeric and
more preferably pre-tensioned prior to attachment to the article so
as to provide a contracted waist and/or leg feature. The waist
and/or leg band elements may comprise a zero-strain laminate or a
pre-stretched laminate, a film, a foam, or an elastic nonwoven. If
a laminate, the separate element preferably additionally comprises
at least one elastomeric element such as an elastomeric film, a
printed elastomeric pattern, elastic strands, or an elastic
nonwoven or foam. The distal edge of the waist and/or leg band may
be aligned with the distal edge of the article, may extend beyond
the edge of the article, or may terminate inboard of the article
edge. In certain embodiments, the waist and/or leg band may at
least partially wrap around the edge of the article and may be
bonded to both the inner and outer surfaces of the article, or a
component thereof.
[0244] Additionally, in some embodiments, the diaper 20 may
comprise finished outer leg cuffs. Finished outer leg cuffs and
waist edges are discussed in U.S. Pat. No. 5,797,824 and U.S. Pat.
No. 7,013,941, while the latter also discusses methods and an
apparatus for applying the material.
[0245] In certain alternative embodiments, the waist edge may be
nonparallel to the lateral centerline of the article. Nonlinear
waist edges may be convex or concave relative to the lateral
centerline, or may have portions which are concave and other
portions which are convex relative to the lateral centerline. The
waist edge is preferably symmetric relative to the longitudinal
centerline, but embodiments are contemplated having a waist edge
asymmetric relative to the longitudinal axis.
[0246] Additionally, in some embodiments, in order to provide more
comfort and fit to the wearer, the leg elastics may be joined to
the chassis 21 of the diaper 20 such that the leg elastics are
curved. In some embodiments, the elastics can be applied in a
direction which is generally parallel to the longitudinal
centerline. In some embodiments, the leg elastics can be applied in
a curvilinear configuration. The leg elastics may be joined to the
chassis 21 in any suitable manner known in the art whether the leg
elastics are curved or otherwise.
[0247] Referring now to FIG. 9, when the diaper 20 is configured as
a pull on diaper, the diaper 20 is worn on the lower torso of a
wearer. As shown, when a first side panel 902 is joined to a second
side panel 904, the end edges 56 encircle the waist of the wearer
while, at the same time, the chassis side edges 54 define leg
openings that receive the legs of the wearer. The crotch region 37
(shown in FIG. 1A) is generally positioned between the legs of the
wearer, such that the absorbent core 26 extends from the front
waist region 36 through the crotch region 37 to the back waist
region 38.
[0248] In some embodiments, the first and/or second side panel 902
and 904, can be formed of discrete separate elements affixed to the
diaper 20. In some embodiments, the first and/or second side panel
902, 904, can be formed from a unitary piece of material that is
neither divided nor discontinuous with an element of the diaper 20.
For example, in some embodiments, the side panels may comprise a
portion of a topsheet. As another example, the side panels may
comprise a portion of a backsheet. As yet another example, the side
panels may comprise a portion of a barrier leg cuff (discussed
hereafter).
[0249] The side panels 902 and 904 can be extensible or can be
elastically extensible. While extensible side panels may be
constructed in a number of configurations, examples of diapers with
extensible side panels are disclosed in U.S. Pat. No. 4,857,067,
entitled "Disposable Diaper Having Shirred Ears" issued to Wood, et
al. on Aug. 15, 1989; U.S. Pat. No. 4,381,781 issued to Sciaraffa,
et al. on May 3, 1983; U.S. Pat. No. 4,938,753 issued to Van
Gompel, et al. on Jul. 3, 1990; in U.S. Pat. No. 5,151,092 issued
to Buell et al. on Sep. 29, 1992; U.S. Pat. No. 6,677,258 issued to
Carroll et al. on Jan. 13, 2004; U.S. patent application Ser. No.
10/396,977 filed on Mar. 25, 2003, U.S. Pat. No. 5,580,411 entitled
"Zero Scrap Method For Manufacturing Side Panels For Absorbent
Articles" issued to Nease, et al. on Dec. 3, 1996; and U.S. Pat.
No. 6,004,306 entitled "Absorbent Article With Multi-Directional
Extensible Side Panels" issued to Robles et al. on Dec. 21,
1999.
[0250] The diaper 20 can be preformed by the manufacturer to create
a pull-on diaper or pant. Specifically, the diaper 20 may include
left and right closed side seams 34, each disposed at regions
proximal the front and back ends of side edges 54. Each side seam
34 can be closed by buttressing and subsequently attaching a given
side edge 54 in the front and back waist regions 36 and 38 either
using a permanent seam or refastenable closure member. It should be
appreciated that side edges can alternatively be attached in an
exterior surface-to-exterior surface configuration, interior
surface-to-interior surface configuration, or interior
surface-to-exterior surface (overlapping) configuration.
[0251] Because the diaper 20 is configured as a pull-on diaper,
both side seams 34 can be closed prior to the application of the
article to a wearer. In some embodiments, the diaper 20 can be
configured such that the diaper 20 is prefastened by the
manufacturer, i.e. the caregiver or wearer does not have to fasten
the diaper 20 upon removal of the diaper from a package 40 (shown
in FIG. 10). In some embodiments, the diaper 20 can be unfastened
in the package 40, i.e. the caregiver or wearer fastens the diaper
20 prior to donning the diaper 20 on the wearer such that the
diaper 20 is configured as a pull-on.
[0252] The side seams 34 can be closed in accordance with any known
techniques or methods known in the art. For instance, the seams 34
can be formed with a permanent seam, which can include a bond
formed by heat sealing such as ultrasonic bonding, high pressure
bonding, RF (radio frequency) bonding, hot air bonding, heated
point bonding, and the like as appreciated by one having ordinary
skill in the art.
[0253] As another example, the side seams 34 may comprise fastening
elements which are refastenable. The fastening elements may
comprise any refastenable fastening elements known in the art. For
example, the fastening elements may comprise hook and loop
fasteners, hook and hook fasteners, macrofasteners, tape fasteners,
adhesive fasteners, cohesive fasteners, magnetic fasteners,
hermaphrodidic fasteners, buttons, snaps, tab and slot fasteners,
and the like. Some suitable examples of fastening systems and/or
fastening elements are discussed in U.S. Pat. Nos. 3,848,594;
4,662,875; 4,846,815; 4,894,060; 4,946,527; 5,151,092; 5,221,274;
6,432,098; U.S. patent application Ser. No. 11/240,943, entitled,
"Anti-Pop Open Macrofasteners" filed on Sep. 30, 2005; U.S. patent
application Ser. No. 11/240,838, entitled, "A Fastening System
Having Multiple Engagement Orientations", filed on Sep. 30, 2005.
Additionally, various suitable pant configurations are disclosed in
U.S. Pat. No. 5,246,433; U.S. Pat. No. 5,569,234; U.S. Pat. No.
6,120,487; U.S. Pat. No. 6,120,489; U.S. Pat. No. 4,940,464; U.S.
Pat. No. 5,092,861; U.S. Pat. No. 5,897,545; U.S. Pat. No.
5,957,908; and U.S. Patent Publication No. 2003/0233082 A1
(published on Dec. 18, 2003 to Mark J. Kline, et al.).
[0254] In other embodiments, secondary fasteners may be employed to
enable adjustment of the article once the article has been applied
to a wearer. Secondary fasteners serve to increase the tension
(i.e., "cinch") in the waist hoop subsequent to application in
order to provide enhanced sustained fit of the article. Secondary
fasteners may include any type of fastener as known in the art and
may be associated with a stretch element that aids in increasing
the tension in the waist hoop.
[0255] Alternatively, the closed side seams 34 can be formed as
disclosed in U.S. Pat. No. 5,779,831; U.S. Pat. No. 5,772,825; U.S.
Pat. No. 5,607,537; U.S. Pat. No. 5,622,589; U.S. Pat. No.
5,662,638; U.S. Pat. No. 6,042,673; and U.S. Pat. No. 6,726,792.
The aforementioned patents disclose various processing methods to
provide absorbent pull-on diapers. One of the processes utilizes a
final knife followed by a reciprocating tucker blade that pushes
the pad from a horizontal orientation to a vertical orientation and
a vacuum conveyor belt that holds the pad through a high pressure
side seaming unit. The side seaming unit is followed by a slitter
that trims the pant edges to provide a finished seam edge. An
alternative method disclosed in the aforementioned patents involves
cutting the pad in the final knife and bi-folding the pad
collecting the pads in a "waterwheel" stacker (a rotary slotted
wheel). The bonding is accomplished while the pad is held in place
on the rotating wheel.
[0256] The present invention therefore recognizes that a plurality
of pull-on diapers 20 can be pre-formed with closed side seams 34
and subsequently packaged and delivered to a user to prevent the
need for the user (which could be the wearer) to close the side
edges 54 prior to securing the diaper 20 on the wearer.
Accordingly, referring to FIG. 10, the present invention includes
the method of providing a plurality of pull-on diapers 20 of the
type described above, and placing the diapers 20 into a closed
package 40 that retains the diapers 20. Accordingly, when the end
user opens the packaging 40, the pull-on diaper 20 can be donned on
the wearer more easily than conventional taped diapers. Embodiments
comprising taped diapers are discussed hereafter.
Other Embodiments
[0257] One having ordinary skill in the art will appreciate that
the anchoring system 42 of the present invention can assume many
alternative configurations that decouple forces from the core and
the outer cover and direct the decoupled forces to the wearer's hip
region. It will thus be apparent that any of the features of
anchoring system elements (e.g., the circumferential anchoring
member, anchoring members, and the LDEs) can be combined in any
desired manner in accordance with the principles of the present
invention. Some additional embodiments of anchoring systems have
been provided heretofore. Still other exemplary embodiments
follow.
[0258] Additionally, one of ordinary skill in the art will
appreciate that the anchoring system can be adapted to a number of
different core assembly configurations and diaper configurations.
For example, diapers constructed in accordance with the present
invention may comprise additional elements from those discussed
heretofore. Some exemplary core assembly and diaper assembly
configurations are provided hereafter.
[0259] With regard to FIGS. 11 and 12A, in some embodiments, the
diaper 20 may further comprise a stretchable waist cover 1523 which
may be attached to the diaper 20 in the first waist region 36
and/or the second waist region 38. The waist cover makes it
possible to effectively manage the edges of the discrete core
bucket when the core bucket is not attached to the outer cover
along its full length, but only in a narrow region in the center.
Without the waist cover, the edges of the core bucket would need to
be bonded to the outer cover, thus compromising outer cover
stretch. As shown in FIG. 11, in some embodiments, the waist cover
1523 can be full width, e.g. extending from the first side edge 54
to the second side edge 54 in the first waist region 36 and/or the
second region 38. A full width waist cover 1523 may be joined to a
portion of the core assembly 23 proximate to an end of the core
assembly 23, may be joined to the chassis 21 adjacent to the side
edges 54, and/or may be joined to the waistband 43.
[0260] As shown in FIG. 12A, in some embodiments, the waist cover
1523 may extend laterally about the same width as the core assembly
23. The waist cover 1523, as shown in FIG. 12A, in some
embodiments, may be joined proximate to an end of the core assembly
23 and/or the waistband 43. In one specific embodiment, the diaper
20 may comprise the waist cover 1523 which has a width which is
generally about equal to the width of the core assembly 23. In an
alternate embodiment, the waist cover is formed by a discrete
waistband attached to the inner surface of the article and
extending longitudinally inboard a sufficient distance to cover the
longitudinal ends of the core. In this embodiment, the waistband
may be bonded to the outer cover proximate the waist edge and along
its longitudinal edges, but not to the core assembly. In a further
alternate embodiment wherein the core assembly comprises a "bucket"
construction and wherein the bucket core assembly has a
longitudinal dimension smaller than the longitudinal dimension of
the article, the waist cover may comprise an extension of the
topsheet portion of the bucket core assembly affixed to the outer
cover proximate the waist edge of the article. In this embodiment,
lateral extensibility in the waist cover region is provided via use
of an extensible topsheet and/or mechanical activation (incremental
stretching) of the portion of the topsheet extending beyond the
bucket core assembly.
[0261] The waist cover 1523 may have several functions. For
example, the waist cover 1523 may prevent the ends of the core
assembly 23 disposed nearest to the first waist region 36 and the
second waist region 38, which may not be bonded to the outer cover
24, from flipping over or buckling during product
application/wearing. It should be noted that by not locking the
stretchable outer cover 24 down with the longitudinal ends of the
core assembly 23, the diaper 20 may be capable of more stretch in
the longitudinal direction, and thus capable of providing a better
conforming fit. As another example, the waist cover 1523 may
improve aesthetics by hiding any non-bonded ends of the core
assembly 23. As yet another example, the anchoring bands 44', 44'',
and/or LDEs 46 can be attached to the waist cover 1523 instead of
the outer cover 24, thus significantly improving outer cover 24
aesthetics and product conformity, especially in the longitudinal
direction. In some embodiments, the anchoring bands 44', 44'',
and/or the LDEs 46, or a portion thereof, can be integral with the
waist cover 1523. For example, portions of the waist cover 1523
which are not the anchoring bands 44', 44'', and/or the LDEs 46 may
be incrementally stretched more so than the anchoring bands 44',
44'', and/or the LDEs 46. The waist cover 1523 can be treated as
described above with regard to the integral formation of the
anchoring system in the outer cover.
[0262] In some embodiments, the waist cover 1523 can be stretchable
in at least one direction (lateral or longitudinal), preferably in
both. Also, in some embodiments, the waist cover 1523 may be
elastic. The waist covers 1523 may utilize any suitable material
known in the art. Some suitable examples of material suitable for
use as the waist cover 1523 include some of the examples provided
for the outer cover 24. Additionally, the waist covers 1523 may
have the same properties as the outer cover 24 described
heretofore, e.g. force at 15% strain and % set (per the Hysteresis
Test provided hereafter). Additionally, the waist cover material
307 is preferably a skin friendly, soft, and liquid permeable,
stretchable in machine direction material. Suitable materials are
activatable nonwoven and apertured nonwoven material as described
in U.S. Pat. No. 5,342,338 6,680,422B2.
[0263] The anchoring bands 44' and/or 44'' can be partly or fully
attached to either the waist cover 1523 or the outer cover 24 or
both, in some embodiments. For example, anchoring band 44' may be
attached to the outer cover 24, while anchoring band 44'' may be
attached to the waist cover 1523, or vice versa. One skilled in the
art will appreciate that the anchoring bands 44' and 44'' can be
positioned at the desired location on the wearer's body to carry
the desired level of force/modulus regardless of whether the
anchoring bands are partially or fully attached to the waist cover
1523, the outer cover 24, or both.
[0264] In order to manage the edges of the core bucket, in some
embodiments, a carrier web may be attached to the core bucket, the
carrier web being the full length of the product. The carrier web
is extensible in either the lateral or longitudinal direction, or
both. The carrier web may also be elastic. The carrier web may be a
nonwoven or a film. In some embodiments, the carrier web is
incrementally stretched at least at one of the two longitudinal
ends in and near the waist band area, or even over substantially
all of the carrier web. This incremental stretching may be done
prior to or after bonding the carrier web to the outer cover in the
waist band area. This carrier web may be attached to the garment
facing side of the core bucket or anywhere inside the core bucket.
This carrier web is longer than the core bucket and either the same
as or less than the length of the outer cover. In the embodiment of
FIG. 12B, an absorbent article 1202 has a chassis 1211-2, an outer
cover, a carrier web 1218-2, and an absorbent core 1290-2 with ends
1290-E-2. The outer cover has an outer cover length 1207-2-L, which
is about the same as a carrier web length 1218-2-L of the carrier
web 1218-2. The carrier web 1218-2 includes activated regions
1218-A-2. The carrier web 1218-2 is attached to the outer cover at
locations 1218-B-2.
[0265] In some embodiments, one of the components of the core
bucket may serve the function of the carrier web. For example,
either the topsheet (or body side liner), or the breathable
polyethylene film, or the barrier leg cuff or combinations thereof
may be made longer than the core bucket and incrementally stretched
at the longitudinal ends. These components of the core bucket that
are about the length of the product are then attached to the outer
cover in the waist band area. In the embodiment of FIG. 12C, an
absorbent article 1203 has a chassis 1211-3, an outer cover, a
full-length topsheet 1205-3, and an absorbent core 1290-3 with ends
1290-E-3. The outer cover has an outer cover length 1207-3-L, which
is about the same as a topsheet length 1205-3-L of the full-length
topsheet 1205-3. The full-length topsheet 1205-3 includes activated
ends 1205-A-3 past the ends 1290-E-3 of the absorbent core 1290-3.
The carrier web 1218-2 is attached to the outer cover at location
1218-B-3.
[0266] With regard to FIGS. 13A-13C, an absorbent article 120 is
illustrated in accordance with an alternative embodiment, wherein
reference numerals of elements illustrated in FIGS. 13A-13C
correspond to like elements of FIGS. 1A-1C and are incremented by
100 for the purposes of clarity and convenience.
[0267] The absorbent article 120 may be constructed similar to the
absorbent article 20. However, in some embodiments, the chassis 121
may include a liquid pervious topsheet 122, and a liquid impervious
outer cover 124 joined to the topsheet 122 proximal the lateral end
edges 156 and the longitudinal side edges 154 via any suitable
adhesive or cohesive 132. As described above, the outer cover 124
can advantageously be stretchable in one or more directions,
preferably biaxially stretchable, and more preferably biaxially
elastic, thereby enhancing both the comfort of the diaper 120 on
the wearer and the conformability to the wearer's anatomy during
movement.
[0268] A core assembly 123 may include an absorbent core 126 that
is positioned between the topsheet 122 and the outer cover 124. In
some embodiments, the outer cover 124 and the topsheet 122 are
stretchable, either axially or biaxially; and the core 126 can be
said to "float" between the topsheet 122 and the outer cover 124.
In some floating core embodiments, the core, or any components of
the core, may not be bonded to the topsheet and/or outer cover. In
other floating core embodiments, the core is bonded to the topsheet
and/or outer cover over a limited portion of its surface area so as
to maximize the "underwear-like" nature of the outer cover (i.e.,
the outer cover is substantially decoupled from the core or loads
generated by the core or contents thereof). For example, a floating
core may be bonded to the topsheet and/or outer cover over less
than 50% of its surface area, and preferably less than 25% of its
surface area. The floating cores of the present invention may be
bonded to the topsheet and/or outer cover over an area between
about 2 percent and about 20 percent of the core surface area. The
absorbent core 126 can be disposed symmetrically or asymmetrically
with respect to either or both of the longitudinal centerline 200
and the lateral centerline 210. For example, as shown in FIG. 13A,
the absorbent core 126 is symmetrical with respect to both the
longitudinal centerline 200 and the lateral centerline 210.
[0269] As shown in FIG. 13B, the topsheet 122 can be disposed
adjacent the body-facing surface of the absorbent core 126, while
the outer cover 124 can be disposed adjacent the garment-facing
surface of the absorbent core 126. The topsheet 122 can be
(partially) attached to the core 126 via the adhesive or cohesive
132 or any suitable means known in the art. In another embodiment
the topsheet 122 and outer cover 124 are not directly attached to
the core. Rather the core is only connected to the outer cover and
the topsheet via the LDE(s) and the CAM(s). In this execution it
may be desirable to reduce the coefficient of friction of the core
against the topsheet and/or the coefficient of friction of the core
against the outer cover. In one embodiment, the outer cover 124 is
substantially impervious to liquids. It should be appreciated that
the topsheet 122 can be attached to the core 126 and/or the outer
cover 124 and that the outer cover 124 can be attached to the core
126 and/or the topsheet 122.
[0270] It should be further recognized that other structures,
elements, or substrates can be positioned between the core 126 and
the topsheet 122 and/or outer cover 124. For instance, the core 126
can be disposed between the topsheet 122 and a breathable liquid
impermeable film formed from polyethylene or the like. In such an
embodiment, the outer cover 124 could be pervious to liquids, as
described above with reference to FIG. 1A.
[0271] As shown in FIG. 13A, in some embodiments, the topsheet 122
and the outer cover 124 have length and width dimensions generally
larger than those of the absorbent core 126. The topsheet 122 and
the outer cover 124 can extend beyond the lateral and longitudinal
edges of the absorbent core 126 to form the periphery of the diaper
120. While the topsheet 122, the outer cover 124, and the absorbent
core 126, can include many different materials and can be assembled
in a variety of well known configurations, suitable diaper
materials and configurations are described generally in U.S. Pat.
No. 3,860,003 entitled "Contractible Side Portions for Disposable
Diaper" which issued to Kenneth B. Buell on Jan. 14, 1975; and U.S.
Pat. No. 5,151,092 issued to Buell on Sep. 9, 1992; and U.S. Pat.
No. 5,221,274 issued to Buell on Jun. 22, 1993.
[0272] The topsheet 122 can be configured in a similar manner to
the outer cover 124. Additionally, in some embodiments, the
anchoring system 142 of the present invention may be integral with
the topsheet 122. For example, portions of the topsheet 122 which
do not comprise a portion of the anchoring system 142 can be
mechanically activated to a greater extent than portions of the
topsheet 122 comprising the anchoring system 142. The topsheet 122
can be treated as described above with regard to the integral
formation of the anchoring system in the outer cover.
[0273] The diaper 120 can further include a pair of opposing and
longitudinally extending barrier leg cuffs 135 that extend out from
the inner body-facing surface 150 of the chassis 121 to provide a
seal against the wearer's body and improve containment of liquids
and other body exudates. Each barrier leg cuff 135 can include
several different embodiments for reducing the leakage of body
exudates in the leg regions. Some suitable examples of barrier leg
cuffs are discussed in U.S. Pat. No. 3,860,003; U.S. Pat. No.
4,909,803; and U.S. Pat. No. 4,695,278.
[0274] In some embodiments, the barrier leg cuffs 135 can be
generally parallel to the longitudinal centerline 200 of the diaper
120. However, embodiments are contemplated where the barrier leg
cuffs 135 are curved outward. For example, the spacing between the
barrier leg cuffs 135 may be less in the crotch region 137 and more
in the waist regions 136 and 138.
[0275] The diaper 120 may further comprise a waistband 143 that
helps provide improved fit and containment, as is appreciated by
one having ordinary skill in the art. The waistband 143 may be
configured similar to the waistband 43 described heretofore. In
contrast, embodiments are contemplated where the anchoring bands
144' and/or 144'' generally form at least a portion of the end edge
156 of the diaper 120.
[0276] Disposable diapers are often constructed so as to have at
least one elastic waistband 143 positioned in the front waist
region 136 and/or back waist region 136. Furthermore, while in some
embodiments the elastic waistband 143 or any of its constituent
elements can include a separate element affixed to the diaper 120,
the waistband 143 need not be separately affixed to the diaper 120.
For instance, the elastic waistband 143 can be constructed as an
extension of other elements of the diaper 120 such as the outer
cover 124, the topsheet 122 or both the outer cover 124 and the
topsheet 122. Examples of suitable waistbands include those
described in U.S. Pat. No. 4,515,595; U.S. Pat. No. 5,151,092; and
U.S. Pat. No. 5,221,274.
[0277] The diaper 120 also includes a leg band or leg elastic that
helps provide improved fit and containment, as is appreciated by
one having ordinary skill in the art. The leg band is that portion
or zone of the diaper 120, which is intended to elastically expand
and contract to dynamically fit the wearer's leg. Leg elastics may
include several different embodiments for reducing the leakage of
body exudates in the leg regions. Leg elastics and contractible leg
openings are discussed in U.S. Pat. No. 3,860,003; U.S. Pat. No.
4,909,803; U.S. Pat. No. 4,695,278; and U.S. Pat. No.
4,795,454.
[0278] Additionally, in some embodiments, in order to provide more
comfort and fit to the wearer, the leg elastics may be joined to
the chassis 121 of the diaper 120 such that the leg elastics are
curved. In some embodiments, the elastics can be applied in a
direction which is generally parallel to the longitudinal
centerline. In some embodiments, the leg elastics can be applied in
a curvilinear configuration. The elastics may be applied to the
chassis 121 by any suitable means known in the art.
[0279] The diaper 120 further includes an anchoring system 142
(shown in FIG. 13A) of the type described above with reference to
FIGS. 1A-1C that is intended to fit to the pelvic region of the
torso and that supports the core 126 and central chassis 121, and
directs the load forces to at least a portion of the wearer's waist
region where the forces can be coupled into the wearer's body.
During wear, the waist and leg perimeters, 156 and 154,
respectively, move with the parts of the body (spine and legs,
respectively) that can move relative to the pelvis. Thus these
perimeters can move relative to the anchoring system 142, which, in
turn, changes the distances between the perimeters and the
anchoring system 142. The waist and leg perimeters can be
mechanically isolated from the anchoring system 142 by a bi-axially
stretchable outer cover 124, "BSOC", and or a biaxially stretchable
topsheet, both designed to minimize forces that arise between the
waist or leg perimeters and the anchoring system from movement of
the legs and spine relative to the pelvis.
[0280] As shown in FIGS. 13A-13C, the diaper 120 may further
comprise a pair of anchoring bands 144' and 144'' which can form a
circumferential anchoring member as described heretofore with
regard to the CAM 44A (shown in FIG. 2A). In some embodiments, the
anchoring bands 144' and/or 144'' can be attached to the
wearer-facing surface of the outer cover 124 via any suitable
adhesive or cohesive. When the diaper 120 is preformed in to a
pant, the anchoring bands 144' and 144'' are operatively connected
via the side seam or closure member to form the continuous
circumferential anchoring member that circumscribes the wearer's
lower torso region.
[0281] As shown in FIG. 13A, the diaper 120 may further comprise a
plurality of LDEs 146. For example, as shown, two LDEs 146 may be
disposed in the first waist region 136 extending outward from the
core 126 toward their respective side edges 154. Similarly, two
LDEs 146 may be disposed in the second waist region 138 extending
outward from the core 126 toward their respective side edges 154.
Additionally, the LDEs 146 can extend laterally outward from the
core 126 and toward the corresponding end edge 156 and terminate at
opposing ends that can be joined to the inner (i.e., body-facing)
surface or the outer-facing surface of the circumferential
anchoring member at the connection zones 148.
[0282] In the embodiment illustrated in 13A-13C, the LDEs 146 may
be joined to the garment-facing surface of the core 126 at
attachment zones 148. The LDEs 146 may be joined to the core 126 by
any suitable means known in the art. For example, the LDEs 146 may
be joined to the core 126 by any suitable adhesive, cohesive, or
the like. Alternatively, the LDEs 146 can be joined to the
wearer-facing surface of the core 126.
[0283] In the embodiment illustrated in FIG. 13A, the topsheet 122
can be joined to the outer cover 124 along the perimeter of the
absorbent article 120 with an adhesive. Alternatively, the topsheet
122 can be joined to the outer cover 124 in any area in which the
topsheet 122 and outer cover 124 overlap, so long as the bonded
area lies outside the core 126. However, the bonds should be
constructed such that movement or otherwise suitable operation of
the anchoring system 142 is unencumbered and, preferably, such that
the bonded region remains stretchable
[0284] As described above, the anchoring bands 144' and/or 144''
can be attached to the body facing side of the outer cover 124, as
illustrated in FIG. 13C. This outer cover 124 can be formed from a
nonwoven or a laminate of a nonwoven and a water-impermeable,
breathable film. If the outer cover 124 is formed of multiple
layers 164, 162, e.g. breathable film and nonwoven, the CAM or a
portion thereof, e.g. anchoring band 144'' could alternatively be
embedded in between these two layers as illustrated in FIG. 13D.
The CAM or a portion thereof, e.g. anchoring band 144'', can also
be either attached on one side of the topsheet 122 as illustrated
in FIG. 13E, or embedded between two layers that are part of a
multi-layered topsheet. The CAM or a portion thereof can be
attached to the topsheet 122 and/or outer cover 124 at discrete
locations or can be fully attached as appreciated by one having
ordinary skill in the art. Partial bonding of the CAM to the
topsheet 122 or outer cover 124 may allow the CAM to stretch more
freely.
[0285] A suitable outer layer 162 (shown in FIG. 13D) is available
from Corovin GmbH, Peine, Germany as supplier code A18AH0, and a
suitable inner layer 164 is available from RKW Gronau GmbH, Gronau,
Germany as supplier code PGBR4WPR. While a variety of outer cover
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.
[0286] With regard to FIG. 13D, where the outer cover 124 comprises
a bi-laminate, the outer layer 162 can be made of a soft, non-woven
material, while the inner layer 164 can be made of a substantially
liquid-impermeable film. The outer layer 162 and the inner layer
164 can be attached together by adhesive or any other suitable
material or method. Accordingly, in some embodiments, the CAM or
portion thereof, e.g. anchoring band 144'', can be joined to the
inner surface of the inner layer 164.
[0287] If the inner layer 164 is liquid-impermeable, then the outer
layer 162 need not be liquid-impermeable and can be formed from a
traditional bi-axially stretchable material or a biaxially
stretchable synthetic fibrous web material, thereby simulating
conventional underwear. The laterally outer ends of the outer layer
162 can be attached to the laterally outer ends of the topsheet 122
by any suitable means known in the art, for example, via adhesive,
cohesive, or the like.
[0288] Accordingly, as illustrated in FIG. 13D, the CAM or portion
thereof, e.g. anchoring band 144'' can be attached to the outer
cover 124 laminate. In these embodiments, the LDEs 146 may be
joined to the inner-facing surface of the inner layer 164 in the
manner described above, thereby operatively coupling the core 126
to the circumferential anchoring band 144''.
[0289] Referring now to FIG. 13E, in particular, the CAM or portion
thereof, e.g. 144'', can be attached to the garment-facing surface
of the topsheet 122 via any suitable means known in the art, for
example via adhesive, cohesive, or the like. The laterally outer
ends of the CAM may be, in turn, attached to the outer cover 124
via adhesive, cohesive, or the like 132. The LDEs 146 may be, in
turn, connected to the exposed garment-facing surface of the CAM or
portion thereof, e.g. 144'', at connection zones 148. In this
illustrated embodiment, the topsheet is preferably stretchable or
elastic, and more preferably biaxially stretchable or elastic.
[0290] In this case, the topsheet 122 can be fabricated as a
biaxially stretchable layer. The LDEs 146 can also be partly or
fully attached to the topsheet 122, or integrated into the topsheet
by fabricating the topsheet 122 with recoverable biaxial
stretchability at low forces everywhere except at the location
where the topsheet 122 would overlap the LDEs 146 if the discrete
LDEs were present, as described above with reference to the outer
cover 124.
[0291] It should be appreciated that the CAM need not be a discrete
structure, but could instead comprise a mechanically, thermally, or
chemically treated portion of the outer cover 124 (i.e., an
integral structure) to provide the desired structural properties
described herein. For example, during the process of making a
biaxially stretchable outer cover 124, a portion can be kept
inextensible (e.g., where the outer cover overlaps the CAM) as
discussed with regard to FIG. 8. Alternatively, a first portion of
the CAM may be a discrete band or other separate element that is
attached to the chassis 121, while a second portion of
circumferential anchoring member is integral with the outer cover
124 to which the discrete band or other separate element is
attached.
[0292] The LDEs 146 can be configured as described herein. For
example, the LDEs 146 and/or CAM 144 may be joined to the outer
cover 124 as discrete elements or may be integral with the outer
cover 124 as described previously.
[0293] Referring now to FIG. 14, embodiments are contemplated where
anchoring bands 144' and/or 144'' are directly joined to a core
assembly. For example, the anchoring bands 144' and 144'' may be
joined to the core assembly 123 without the use of LDEs. Therefore,
in some embodiments, the force from the core assembly can be
directly transmitted to the anchoring bands 144' and/or 144'' via
connection zones 148. Additionally, embodiments comprising waist
covers as discussed heretofore may be utilized in the absorbent
articles configured in accordance with FIG. 14. Also, in these
contemplated embodiments, the CAM 144 or portion thereof may be
joined to the waist cover(s) or may be integral with the waist
cover(s).
[0294] As shown in FIG. 14, in some embodiments, one or both
longitudinal ends of the core 126 can extend from the first
anchoring band 144' to the second anchoring band 144'' (it should
further be appreciated that the core 126 could extend beyond
anchoring bands 144' and 144''). The anchoring bands 144' and/or
144'' may be joined to the core 126 by any suitable means known in
the art. Some suitable examples include adhesives, cohesives, heat
seals such as ultrasonic bonds, high pressure bonds, RF (radio
frequency) bonds, hot air bonds, heated point bonds, and the like
as appreciated by one having ordinary skill in the art.
[0295] Referring now to FIGS. 15A-15G, the present inventors
recognize that the principles of the present invention as described
above with respect to pant-like garments are equally applicable to
garments, such as absorbent articles, that are configured as taped
diapers (i.e., diapers that are not necessarily pre-closed within a
package of absorbent articles). While some of the description above
pertaining to pant-like garments is included in the description
below of taped diapers for the purposes of form and clarity, the
omission of other portions above from the description below does
not imply that those omitted portions are not, or cannot be,
incorporated into a taped diaper. Rather, the omitted portions are
not described below to minimize redundant description throughout
this document. Accordingly, unless otherwise specified, it should
be appreciated that all features described above with respect to
the pant-like absorbent articles can also be incorporated into
taped diapers. Furthermore, unless otherwise specified, it should
be appreciated that all features described below with respect to
taped diapers can also be incorporated into pant-like garments. For
the purposes of form and clarity, a taped absorbent article 220 is
illustrated in FIG. 15A with like reference numerals corresponding
to similar elements of FIGS. 1A-1C incremented by 200.
[0296] As shown in FIG. 15A, the absorbent article 220 has a
central longitudinal centerline 300 and a central lateral
centerline 310. The absorbent article 220 may include a
substantially hourglass-shaped chassis 221 having a first, or
front, waist region 236, a second, or back, waist region 238
opposed to the front waist region 236, and a crotch region 237
located between the front waist region 236 and the back waist
region 238. The waist regions 236 and 238 generally comprise those
portions of the diaper 220 which, when the diaper 220 is worn,
encircle the waist of the wearer. The waist regions 236 and 238 can
include elastic elements such that they gather about the waist of
the wearer to provide improved fit and containment. The crotch
region 237 is that portion of the diaper 220 which, when the diaper
220 is worn, is generally positioned between the legs of the
wearer. The outer periphery of the chassis 221 is defined by
lateral end edges 256 that can be oriented generally parallel to
the lateral centerline 310, and by longitudinal side edges 254 that
can be oriented generally parallel to the longitudinal centerline
300 or, for better fit, can be curved or angled, as illustrated, to
produce an "hourglass" shaped garment when viewed in a plan view.
In some embodiments, the longitudinal centerline 300 may bisect the
end edges 256 while the lateral centerline 310 may bisect the side
edges 254.
[0297] The chassis 221 can comprise a liquid pervious topsheet 222,
and a liquid impervious outer cover 224 joined to the topsheet 222
proximal the lateral end edges 256 and the longitudinal side edges
254 via any suitable method known in the art. Some suitable
examples include adhesives or cohesives. While adhesive or cohesive
may be used to connect various absorbent article components as
illustrated and described herein, one having ordinary skill in the
art will appreciate that any suitable alternative attachment
mechanism can facilitate such connections. Examples of suitable
alternatives include, but are not limited to, thermal bonds, RF
(radio frequency) bonds, pressure bonds, ultrasonic bonds, welds,
stitching, and the like.
[0298] A cover 247 can be disposed about the side edges 254 that
provide the periphery of the leg openings once the diaper 220 is
closed, and thus engage the wearer's legs during use. Similarly, as
shown, in some embodiments, a cover may similarly be disposed about
the end edges 256 that provide the periphery of the waist opening
once the diaper 220 is closed, and thus engages the wearer's waist
during use. In some embodiments, the cover 247 can be elastic and
joined to the outer cover 224 while the cover 247 is under tension
such that upon relaxation gathers the side edges 254. Finished
outer leg cuffs and waist edges are discussed in U.S. Pat. No.
5,797,824 and U.S. Pat. No. 7,013,941, while the latter also
discusses methods and an apparatus for applying the material.
[0299] As described above with respect to absorbent article 220,
the outer cover 224 can advantageously be bi-axially stretchable,
thereby enhancing both the comfort of the diaper 220 on the wearer
and the conformability to the wearer's anatomy during movement. In
some embodiments, a substantially hourglass-shaped absorbent core
assembly 223 can be positioned between the topsheet 222 and the
outer cover 224. In some embodiments the core assembly 223 can be
configured similar to the core assembly 23 described
heretofore.
[0300] As illustrated in FIG. 15C, in some embodiments the core
assembly 223 can be "tacked" (either via an adhesive, cohesive, or
the like) to the outer cover 224 at one or more discrete locations
225, where wearer movement is unlikely to cause the connection
between the core assembly 223 and the outer cover 224 to restrict
outer cover stretchability. These discrete locations are also
referred to herein as regions of low motion. Tacking the core
assembly 223 in this manner would assist in preventing substantial
movement of the core assembly 223 relative to the wearer's body.
One example of a location suitable to tack the core assembly 223 to
the outer cover 224 includes the crotch region 237, and
particularly proximal to the intersection of the longitudinal axis
300 and the lateral axis 310. As illustrated in FIG. 15D, the
remaining regions of the core assembly 223 are not required to be
attached to the outer cover 224. In some embodiments, the bond area
between the core assembly 223 and the outer cover 224 can be
between about 1 cm.sup.2 and about 20 cm.sup.2 or any individual
number within the range. In some embodiments, the core assembly 223
may be bonded to the outer cover 224 wherein the bond area resemble
a strip extending the substantial length of the core assembly 223
and being long and narrow.
[0301] Referring again to FIG. 15A, the diaper 220 can also include
a waistband 243 that helps provide improved fit and containment, as
is appreciated by one having ordinary skill in the art. The
waistband 243 is that portion or zone of the diaper 220, which is
intended to elastically expand and contract to dynamically fit the
wearer's waist. The elastic waistband 243, in some embodiments, may
form at least a portion of the end edge 256 of the diaper 220.
Disposable diapers can be constructed so as to have at least one
elastic waistband positioned in the front waist region 236 and/or
back waist region 238. Furthermore, while in some embodiments the
elastic waistband 243 or any of its constituent elements can
include a separate element affixed to the diaper 220, the waistband
243 need not be separately affixed to the diaper 220, as described
heretofore. The waistband 243 may be configured as described
heretofore.
[0302] The diaper 220 can include a pair of side panels 227 that
extend laterally outward from the longitudinal side edges 254
proximal the lateral end edge 256 in the back waist region 238. The
side panels 227 can be attached to the chassis 221 at attachment
zone 245 using any known attachment apparatus or, alternatively,
the side panels 227 can be formed integrally with the chassis 221.
The side panels 227 may be elastic in some embodiments.
Additionally, in some embodiments, the diaper 220 may further
comprise a pair of side panels extending laterally outward from the
longitudinal side edges 254 in the first waist region 236. The side
panels 227 may be discrete elements which are joined to the first
waist region 236 and/or the second waist region 238. Alternatively,
in some embodiments, the side panels 227 may be integral with a
portion of the diaper 220. For example, the side panels 227 may
comprise a portion of the topsheet 222, outer cover 224, and/or leg
cuffs.
[0303] The disposable absorbent article 220 further comprises a
fastening system 229 which can join at least a portion of the first
waist region 236 with at least a portion of a second waist region
238, preferably to form leg and waist openings. The fastening
system 229 also works with the waistband 243 to maintain lateral
tension about the waist of the wearer. The fastening system 229 may
comprise engaging components 231 which, in some embodiments, can be
disposed on the side panels 227. The fastening system 229 may
further comprise a receiving component 239 which, as illustrated,
is disposed in the front waist region 236. The receiving component
239 can be integral with the chassis 221, or can be connected via a
side panel extending outward from the chassis 221.
[0304] Any suitable engaging element 231 can be used in the present
invention. An example of a suitable engaging element 231 comprises
hook fastening material. The hook fastening material can
mechanically engage fibrous elements of the receiving element 239
so as to provide a secure closure. A hook fastening material
according to the present invention may be manufactured from a wide
range of materials. Suitable materials include nylon, polyester,
polypropylene, or any combination of these materials, or other
materials as are known in the art.
[0305] A suitable hook fastening material comprises a number of
shaped engaging elements projecting from a backing such as the
commercially available material designated Scotchmate.TM. brand No.
FJ3402 available from Minnesota Mining and Manufacturing Company,
St. Paul, Minn. Alternatively, the engaging elements may have any
shape such as hooks, "T's", mushrooms, or any other shape as are
well known in the art. An exemplary hook fastening material is
described in U.S. Pat. No. 4,846,815. Another suitable hook
fastening material comprises an array of prongs formed of
thermoplastic material. Hot melt adhesive thermoplastics, in
particular polyester and polyamide hot melt adhesives, are
particularly well suited for forming the prongs of the hook
fastening material. The prongs, in some embodiments, can be
manufactured using a modified gravure printing process by printing
the thermoplastic material in its molten state onto a substrate in
discrete units, severing the material in a manner that allows
stretching of a portion of the thermoplastic material prior to
severance, and allowing the stretched molten material to "freeze"
resulting in prongs. This hook fastening material and methods and
apparatus for making such a hook fastening material are more fully
detailed in European Patent Application 0 381 087.
[0306] The fastening system 229 may be the primary fastening system
for joining the front and back waist regions 236 and 238. However,
the fastening system 229 may be used alone or in conjunction with
other fastening means such as tab and slot fasteners, tape
fasteners, snaps, buttons, and the like to provide different
fastening characteristics. For example, the fastening system 229
may provide the disposable absorbent article 220 with a disposal
means for fastening the disposable absorbent article 220 in a
configuration convenient for disposal. Further, secondary fastening
means may provide the disposable absorbent article 220 with a means
for adjusting fit or may increase the strength of the connection
between the front waist region 236 and the back waist region
238.
[0307] When the diaper 220 is worn on the lower torso of a wearer,
the end edges 256 encircle the waist of the wearer while, at the
same time, the chassis side edges 254 define leg openings that
receive the legs of the wearer. The crotch region 237 is generally
positioned between the legs of the wearer, such that the absorbent
core assembly 223 extends from the front waist region 236 through
the crotch region 237 to the back waist region 238.
[0308] It should be appreciated that the positions of the side
panels 227 and the receiving elements 239 can be reversed with
respect to the embodiment illustrated in FIG. 15A, such that the
side panels 227 extend from the longitudinal side edges 254
proximal the lateral end edge 256 in the front waist region 236,
while the receiving elements 239 are disposed proximal the lateral
end edge in the back waist region 238. Alternatively still, a pair
of side panels 227 can be disposed in both the front and back waist
regions 236 and 238, with a pair of the side panels in a given
waist region including a fastening member configured to engage the
opposing side panels.
[0309] The present invention recognizes that the core assembly 223
is capable of absorbing substantial loads during use, and that the
fit of conventional diapers can be worsened when the increased
weight and resultant downward forces exerted on the core (and from
the core to other diaper components) cause the absorbent article
220 to sag or otherwise be distended. Accordingly, referring again
to FIGS. 15A-19B the diaper 220 includes an anchoring system 242
similar to the anchoring system 42 described above and illustrated
with respect to absorbent article 20. Like anchoring system 42, the
anchoring system 242 includes a circumferential anchoring member
244 (designated as 244' in the front waist region and 244'' in the
back waist region) that surrounds the wearer's body at the lower
torso region, and a plurality of LDEs 246 connected between the
core assembly 223 and the circumferential anchoring member 244. In
some embodiments, the circumferential anchoring member 244 can be
disposed longitudinally inboard of the elastic waistband 243. In
some embodiments, the CAM 244 may form a portion of the end edge
256 of the diaper 220.
[0310] During use, when the core assembly 223 absorbs an
excremental load, for example, a gravitational and/or inertial
force is applied to the core assembly 223 which tends to push the
core assembly 223 downward. The core assembly 223 transmits the
force to the LDEs 246 which in turn distributes the force to the
CAM 244. The CAM 244 in turn, transfers the force to the wearer's
body (e.g., at the lower torso region). In embodiments comprising
the BSOC, the BSOC can force-decouple a potential pathway between
the core assembly 223 and the anchoring system 242 ensuring that
the anchoring system 242 receives loads from the core assembly 223
only by the LDEs 246 as opposed to receiving loads from the core
assembly 223 by both the LDEs 246 and the outer cover 224. In some
embodiments, substantially all of the load from the core assembly
223 may be transferred to the CAM 244 via the LDEs 246. It will be
thus appreciated that the anchoring system 242 enables the taped
diaper 220 to achieve an enhanced, more comfortable and
underwear-like fit relative to conventional diapers.
[0311] As shown in FIG. 15A, in some embodiments, the CAM 244 may
comprise a first anchoring band segment 244' extending between
opposing side edges 254 in the front waist region 236, and a second
anchoring band segment 244'' extending between opposing side edges
254 in the back waist region 238. While segments 244' and 244'' can
assume any one of a number of configurations as described
heretofore with regard to the CAM and/or anchoring bands, in the
illustrated embodiment, the segment 244' and 244' are substantially
straight and extend laterally across the diaper 220.
[0312] As shown in FIGS. 15B and 15E, the CAM 244 can be attached
to the inner surface (i.e., opposite the garment-facing surface
252) of the outer cover 224 via any suitable means known in the
art, for example, adhesive or cohesive. When the fastening system
229 is closed to correspondingly close the taped diaper 220, the
segments 244' and 244'' are operatively connected to form the
continuous CAM 244 that surrounds the wearer's lower torso
region.
[0313] As shown in FIG. 15A, in some embodiments, the CAM 244 may
comprise one or more connection zones 248 where the LDEs 246 are
joined to the CAM 244. Similarly, connection zones 248 can exist
where the LDEs 246 are joined to the core assembly 223. The LDEs
246 may be configured similarly to the LDEs 46 and 146.
[0314] In some embodiments, the LDEs 246 can comprise bands that
are non-stretchable so as to transfer the gravitational and/or
inertia forces at the core assembly 223 to the connection zone 248
of the circumferential anchoring member 244. In some embodiments,
the LDEs 246 may comprise stretchable and/or elastic bands which
transfer forces from the core assembly 223 to the CAM 244. For
example, during loading of core assembly 223, if the modulus of the
LDEs 246 were designed to stretch by the same amount as the added
load would swell the core; this would prevent the anchoring system
242 from having an added load source from the core swelling.
[0315] In a particular embodiment illustrated in FIG. 15A, four
LDEs 246 are connected at one end to the four corresponding corner
regions, or any portion of the four quadrants formed by the
intersection of the longitudinal 300 and lateral 310 axes of the
article, of the core assembly 223. In the illustrated embodiment,
the LDEs 246 are connected to the outer (i.e., garment-facing)
surface of the core assembly 223. Alternatively, the LDEs 246 can
be connected to the inner (wearer-facing) surface of the core
assembly 223. As illustrated in FIG. 15A, the LDEs 246 can extend
laterally outward from the core 226 and toward the corresponding
end edge 256 and terminate at opposing ends that are connected to
the outer (i.e., garment-facing) surface or the inner-facing
surface of the CAM 244 at the connection zones 248. The LDEs can be
joined to the core assembly 223 and to the CAM 244 via any suitable
method known in the art, for example, any suitable adhesive,
cohesive, or the like. Similar to the embodiment discussed with
regard to FIG. 6, embodiments are contemplated where the connection
zones 248 may comprise a discrete intermediate material which can
be non-stretchable, stretchable, or elastic, in order to allow the
CAM 244 to receive the forces from the core assembly 223 while
preventing the core assembly 223 from sagging away from the
wearer's body during use.
[0316] The outer cover 224 represents a potential force
transmission path between the core assembly 223 and the anchoring
system 242, a force transmission path between the core assembly 223
and the leg perimeters, and a force transmission path between the
anchoring system 242 and the waist perimeter. For enhanced
operation of the anchoring system 242, it may be desirable to force
decouple the above mentioned transmission paths utilizing a
suitable outer cover 224. For example, a suitable outer cover 224
as previously discussed, is a BSOC.
[0317] As shown in FIG. 15F, in some embodiments, the first
anchoring band segment 244' can overlap a portion of the second
anchoring segment band 244''. The receiving component 239 is joined
to 244' which has distal edge 244A and a proximal edge 244B. In a
fastened state, the engaging component 231 engages the receiving
component 239.
[0318] In order for the LDEs 246A and 246B to be properly coupled
into the CAM 244, the overlap between the anchoring bands 244' and
244'' should be disposed between the connection zones 248 of the
LDE 246A and the connection zone 248 of the LDE 246B. Additionally,
in order for the LDEs 246A and 246B to be properly coupled into the
CAM 244, the engaging component 231 should be disposed between the
connection zones 248 of the LDE 246A and the connection zone 248 of
the LDE 246B. For example, as shown, the engaging component 231 can
engage the receiving component 239 adjacent to the distal edge 244A
of the receiving component 239. This positioning represents the
largest circumference possible in the CAM 244, when a corresponding
engaging element is similarly affixed on the opposite side of the
article.
[0319] In contrast, as shown in FIG. 15G, the engaging element 231
is disposed proximate to the connection zone 248 of the LDE 246B.
This embodiment represents a larger configuration for the
positioning of the engagement element 231 with respect to the
connection zone 248 of the LDE 246B. Additionally, this positioning
represents a smaller circumference of the CAM 244, when a
corresponding engaging element is similarly affixed on the opposite
side of the article.
[0320] Referring now to FIG. 16, one alternative embodiment of the
present invention recognizes that the LDEs 246 can be integrally
connected to the circumferential anchoring member 244. For example,
as shown, at least one of the LDEs 246 is integral with its
corresponding anchoring band 244' and/or 244''.
[0321] In some embodiments, as illustrated in FIG. 17, the LDEs 246
can be integrally connected via a spine 251 that extends
longitudinally along the core assembly 223. In particular, at least
a portion of, the spine 251 may be connected to the outer
(garment-facing) surface of the core assembly 223 via an adhesive,
cohesive, or suitable alternative and/or equivalent. In some
embodiments, the spine 251 can be laterally centrally disposed on
the core assembly 223, and can extend between the longitudinal
outer edges of the core assembly 223. As illustrated, in some
embodiments, the spine 251 terminates at both longitudinal ends
short of the longitudinal end of the core assembly 223. The LDEs
246 may extend longitudinally and laterally outboard of the spine
251. Alternatively, in some embodiments, the spine 251 and LDEs 246
can be integrally connected to the circumferential anchoring band
segments 244' and 244'' as illustrated in FIG. 18.
[0322] The spine 251 can provide structural support for the core
assembly 223. For example, conventional cores made up of airfelt
may benefit from the incorporation of the spine 251.
[0323] As shown in FIG. 17, in some embodiments, the LDEs 246 may
be discretely joined to the spine 251 and to the anchoring band
segments 244' and/or 244''. Alternatively, in some embodiments, the
LDEs 246 may be integral with the spine 251 and discretely joined
to the anchoring band 244' and/or 244''. In still other
embodiments, the LDEs 246 may be integral with the anchoring band
244' and/or 244'' and discretely joined to the spine 251. In some
embodiments, such as the embodiment of FIG. 18, the anchoring bands
244' and 244'' and the LDEs 246 and the spine 251 can all be
integral with each other. It should be appreciated that the spine
251 can be formed from the same material as LDEs 46, 146, and 246
or, if LDEs 246 are discretely connected to the spine 251, the
spine can be formed from any suitable alternative material
appreciated by one having ordinary skill in the art, including a
portion of the outer cover subjected to less incremental stretching
than the surrounding regions of the outer cover, as discussed
heretofore.
[0324] Referring to FIGS. 19A and 19B, an absorbent article 320 is
illustrated having reference numerals corresponding to like
elements of FIGS. 1A-1C incremented by 300 for the purposes of
clarity and convenience. The absorbent article 320 can include a
pair of stretchable (e.g., in the machine cross direction) ears 317
(also referred to as an elastically stretchable side panel) that
are attached (e.g., via mechanical, pressure, or ultrasonic bonding
and/or glue etc.) to a chassis 321. The ears are thus stretchable
in a direction substantially parallel to the lateral centerline
410.
[0325] Such stretchable ears are 317 are described, e.g., in U.S.
Pat. No. 5,674,216. Typically they consist of a laminate of an
(breathable) elastomeric film sandwiched (preferably with glue)
between two layers of (preferably activatable) nonwoven such as
DAPP or HEC. After lamination the ears 317 are activated, i.e., via
ring rolling, as e.g. described in U.S. Pat. No. 5,156,793 or in
U.S. Pat. No. 5,167,897 to allow the ears to stretch in the cross
direction.
[0326] Hooks 319 (and associated stiffener element, if desired) may
be applied to the ear during the process of manufacturing the
article or when the ear laminate is produced. Suitable hooks 319
are available from Aplix Corporation as 963 hooks. Additionally,
any hooks discussed heretofore may be utilized.
[0327] The ears 317 can be attached to an activatable auxiliary
nonwoven 315 such as a DAPP or HEC. An example of a suitable DAPP
nonwoven is available under the designation Softspan 200 by BBA
Fiberweb, Brentwood, Tenn.
[0328] An auxiliary nonwoven layer 315 can join the absorbent
assembly 323 and the ears 317 as shown in FIG. 19B. The auxiliary
nonwoven may be folded over to encapsulate the outer leg elastics
363. In this embodiment, the auxiliary nonwoven 315 forms the front
ear 313, the area to attach to back ears 317, and the material that
encapsulates the curved outer elastics 363.
[0329] After the (curved) outer elastics 363 are attached to the
biaxially stretchable outer cover 324 material and the auxiliary
nonwoven 315 is folded over and (glue) bonded to the biaxially
stretchable outer cover 324, the chassis 321 is selectively
activated as e.g. described in U.S. Pat. No. 6,383,431 (Dobrin et
al) in the machine direction and in the cross direction. The core
assembly 323 can be tacked, if desired, to the outer cover 324 at
location 339. An example of a suitable outer leg elastic 363 is
available under the designation item #17087 available from
Fulflex.
[0330] As seen in the drawing, some regions of the chassis 321 are
not activated. These regions will form the chassis part of the
anchoring system 342. The drawing clearly shows the circumferential
anchoring member 344 and the load distribution elements 346
intended to link the core assembly 323 to the circumferential
anchoring member 344. These regions are subjected to substantially
less incremental stretching then the other regions of the outer
cover. As can be seen in this execution the anchoring system 342 is
made of the same structure as the whole chassis 321 via selective
activation and is an intimate part of the outer cover 324.
[0331] In certain embodiments, the circumferential anchoring member
344 exhibits minimal strain under applied tension. An exemplary
circumferential anchoring member 344 stretches only by 2% under a
load of 0.9 N/cm.
[0332] If the unactivated biaxially stretchable outer cover
material is, in its basic state, insufficiently resistant to
extension, the strength of the circumferential anchoring member 344
may be increased via over-bonding the material. Over-bonding works
especially well for nonwovens, but also works for laminates.
Over-bonding, in essence, involves the application of heat and
pressure to selected areas of the biaxially stretchable outer cover
material, thereby melting part of the material and creating
additional bond sites, or even film like structures (rather than
the nonwoven structures).
[0333] It may be desirable to not activate the distal edges (the
areas of the auxiliary nonwoven 315 that extend beyond the
biaxially stretchable outer cover 324) of the auxiliary nonwoven
315. If said distal edges are not activated the web maintains a
portion that has a relatively high modulus. This can be
advantageous for web handling during the process of manufacturing
the absorbent article.
[0334] When activating the chassis 321, care should be taken to not
to create too much fuzz (i.e., dust, lint, loose fibers/material),
create pin-holes, or damage the outer elastics, while achieving the
desired level of lateral and longitudinal extensibility.
[0335] Fuzz creation is undesirable for line hygiene reasons and
because consumers associate low fuzz levels with durability. With
respect to the creation of fuzz, it has been found that it is
desirable to create less than 0.12 mg/cm.sup.2 of fuzz. A suitable
fuzz test method is disclosed in U.S. Pat. No. 5,433,826.
[0336] Fuzz creation can be minimized by selection of appropriate
nonwovens, the right activation process settings (lower strain
rates, less depth of engagement are preferred), and the way how the
auxiliary nonwoven is combined/bonded with the biaxially
stretchable outer cover. In certain embodiments, it is preferable
that the bonding between the auxiliary nonwoven 315 and the
biaxially stretchable outer cover is not too intimate. For example,
spiral glue has been found to be an acceptable method of bonding.
In addition it has been found that it is desirable to activate the
chassis 321 while the (spiral) glue combining the auxiliary
nonwoven with the biaxially stretchable outer cover is still hot to
minimize fuzz and pinhole generation.
[0337] While in this execution the chassis 321 does not need to be
liquid impermeable, it still has been found that it is desirable to
have as few pin-holes as possible. One reason is that the absence
of pinholes is a signal of quality to the consumer as well as a
re-assurance that the product will not leak. In light of this it
has been found that it is desirable to have less than 0.1 pinholes
per linear meter of chassis. In broad terms, a pinhole is a part of
the chassis 321 stretched to 10% in machine direction and to 10% in
cross direction were the opacity is at least 10 units lower than
the average, and the pinhole area is larger than 0.5 mm.sup.2.
[0338] It has been found that in general the same considerations
that reduce fuzz also reduce pin-holes. Beyond the considerations
identical to the fuzz generation it has been found that if the
biaxially stretchable outer cover has a layer that is the main
contributor of the opacity of the biaxially stretchable outer cover
(like a film or a layer of melt blown or nano fibers), then it is
desirable that this layer have elastic properties.
[0339] One way of avoiding the destruction of elastics is to avoid
activating in the areas in which the outer elastics are disposed.
Another way is to decrease the depth of engagement in the areas
containing the outer elastics.
[0340] If desired, a preferably chevron shape landing zone 339 may
be attached (glued) to the biaxially stretchable outer cover. An
example of a suitable landing zone is sold under the designation
NALT 27 chevron shaped landing zone produced by Aplix.
[0341] In some embodiments, biaxially stretchable outer cover 324
materials provide enough loops of fibers on the outside, such that
the hooks 319 can engage with the biaxially stretchable outer cover
324 without the need of an additional landing zone 339. For
example, a biaxially stretchable outer cover 324 may comprise an
SMS nonwoven that is activated in the region typically occupied by
a landing zone and subsequently over-bonded to create sufficient
strength in the lateral direction to form an integral landing zone
from the outer cover material. In other embodiments, the landing
zone can be extensible in both the longitudinal and lateral
directions and may be glued to the center chassis prior to or after
activation.
[0342] A contractible finished waistband (not shown in this figure)
may be applied to the inside, outside, or both, of the center
chassis. Any suitable waistband known in the art may be
utilized.
[0343] After the chassis 321 is activated a self-contained (or
"bucket") core assembly 323, such as that depicted in FIGS. 1A-1C,
may be attached to the chassis 321 by attaching the core to the
LDE(s) 346, the CAM(s) 344, and/or directly to the outer cover 324.
FIG. 19A shows regions 332 where the core assembly 323 is
preferably attached to the chassis 321 and additional regions 311
where the core assembly 323 may be attached to the chassis 321 in
certain embodiments. While the drawing shows the attachment sites
332 as squares, the attachment regions may comprise any suitable
shape. When attaching the core assembly 323 to the chassis 321, the
desire to bond as little area as possible to allow the chassis 321
to stretch and conform to the wearers body as much as possible is
balanced with the desire to bond as much as possible, so that the
core assembly 323 does not easily separate from the rest of the
absorbent article 320.
[0344] One preferred way of attaching the core assembly 323 to the
chassis 321 is to sandwich the core assembly 323 in the front and
back regions 336 and 338 between the center chassis 321 and an
optional waist cover 307. This way the core assembly 323 can not
flip over, but by making the waist cover 307 extensible at least in
the machine direction the ability of the center chassis 321 to
stretch and conform to the wearer's body is less restricted than by
gluing the core assembly 323 to the center chassis 321.
[0345] The waist cover 307 can be configured as discussed
heretofore with regard to the waist cover 1523 (shown in FIGS. 11
and 12A). Additionally, in some embodiments, the CAM 344 and/or
LDEs 346 can be attached to the waist cover 307 instead of the
outer cover 324, thus significantly improving outer cover 324
aesthetics and product conformity, especially in the longitudinal
direction. In some embodiments, the CAM 344 and/or the LDEs 346, or
a portion thereof, can be integral with the waist cover 307. For
example, portions of the waist cover 307 which are not the CAM 344
and/or the LDEs 346 may be incrementally stretched more so than the
CAM 344 and/or the LDEs 346.
[0346] After the core assembly 323 has been attached to the chassis
321, the back ear 317 may be attached and the side notch may be cut
out. After this the diaper 320 may be cut, folded, and put into
bags.
[0347] The advantage of making the diaper 320 this way is that by
assembling the absorbent article in the described sequence, there
is always a part of the web that has a relatively high elastic
modulus, providing easier web handling at high line speeds.
[0348] While a rectangular shaped core assembly 323 is relatively
easy to fabricate, it can be desirable for the absorbent materials
contained inside the core assembly 323 (e.g., nonwoven acquisition
layers, fibrous acquisition layers, cellulose fibers,
superabsorbent polymers, nonwoven forming or containment layers,
etc.) to be shaped. Shaped absorbent materials conform much better
to the wearer's anatomy; give the impression of less bulk between
the legs and the impression of a better fitting product.
[0349] Specifically it has been found that it is desirable that the
width of the absorbent materials in the region of the wearer
crotch. i.e., the width of the core assembly in the crotch region
is no greater than about 50 mm wide (independent of the age of the
wearer). Alternatively, the width of the core in the crotch region
may be up to about 70 mm, or even about 90 mm, in come
embodiments.
[0350] An additional advantage of a relatively narrow core assembly
in the crotch region 337 is that the effective cuff height of the
barrier leg cuffs is increased.
[0351] Similarly, it has been found that it is desirable for the
absorbent materials to be as wide as 110 mm, or even 130 mm in the
front region 336 and in the back region 338 (for babies). For
adults it may be desirable to spread the absorbent materials in the
front and in the back even further.
[0352] The illustrated embodiment can be made from the following
materials in accordance with one aspect of the invention.
[0353] Variations to the embodiment illustrated in FIGS. 19A-19B
could be implemented. For instance, the bucket core assembly 323
could be discrete (i.e., not run the full length of the chassis
321). Furthermore, the biaxially stretchable outer cover 324 could
be folded over and replace the auxiliary nonwoven. Additionally,
rather than attaching the stretch back ears 313, the biaxially
stretchable outer cover 324 could extend the full width of the
article and comprise stretch elements. Finally, rather than making
the anchoring system 342 out of the biaxially stretchable outer
cover 324 via selective activation one could add an anchoring
system made of a nonwoven or of an elastomeric film/nonwoven
laminate attached separately to the core assembly as described
herein.
[0354] FIG. 20A illustrates a plan view of an embodiment of
disposable absorbent article 2000-A with side fasteners 2003 and an
anchoring system 2021. The anchoring system 2021 includes a CAM
2007 and LDEs 2005. The anchoring system 2021 includes stretchable
portions 2051 including stretchable CAM portions 2007-S, disposed
laterally outboard of intersections between the CAM 2007 and the
LDEs 2005.
[0355] FIG. 20B illustrates a plan view of an embodiment of
disposable absorbent article 2000-B with side fasteners 2003 and an
anchoring system 2022. The anchoring system 2022 includes a CAM
2007 and LDEs 2005. The anchoring system 2022 includes stretchable
portions 2052 including stretchable CAM portions 2007-S and
stretchable LDE portions 2005-S, disposed through intersections
between the CAM 2007 and the LDEs 2005.
[0356] FIG. 20C illustrates a plan view of an embodiment of
disposable absorbent article 2000-C with side fasteners 2003 and an
anchoring system 2023. The anchoring system 2023 includes a CAM
2007 and LDEs 2005. The anchoring system 2023 includes stretchable
portions 2053 including stretchable CAM portions 2007-S, disposed
laterally outboard of intersections between the CAM 2007 and the
LDEs 2005.
Test Methods
Hysteresis Test for Elastic Properties
(i) Sample Preparation for the Elastomeric Material
[0357] Samples dimensions are as described below.
[0358] BSOC--(1'' width by 3'' length)
[0359] Topsheet (1'' width by 3'' length)
[0360] CAM--(width of the CAM generally parallel to the
longitudinal axis of the diaper by 3'')
[0361] LDE--(width of the LDE by 3'')
Hysteresis Test For the Elastomeric Composite
[0362] A commercial tensile tester from Instron Engineering Corp.,
Canton, Mass. or SINTECH-MTS Systems Corporation, Eden Prairie,
Minn. (or a comparable tensile tester) is used for this test. The
instrument is interfaced with a computer for controlling the test
speed and other test parameters, and for collecting, calculating
and reporting the data. The hysteresis is measured under typical
laboratory conditions (i.e., room temperature of about 20.degree.
C. and relative humidity of about 50%).
[0363] The procedure for determining hysteresis involves the
following steps: [0364] 1. choose the appropriate jaws and load
cell for the test; the jaws are wide enough to fit the sample,
typically 1'' wide jaws are used; the load cell is chosen so that
the tensile response from the sample tested will be between 25% and
75% of the capacity of the load cells or the load range used,
typically a 50 lb load cell is used; [0365] 2. calibrate the tester
according to the manufacturer's instructions; [0366] 3. set the
gauge length at 25 mm; [0367] 4. place the sample in the flat
surface of the jaws such that the longitudinal axis of the sample
is substantially parallel to the gauge length direction; [0368] 5.
the hysteresis test involves the following steps: [0369] a) pull
the sample to 50% strain at a cross head speed of 10 in./min (254
mm/min)--first cycle loading [0370] b) hold at that strain for 30
seconds and return to 0% strain at the same crosshead speed--first
cycle unloading [0371] c) allow the sample to remain at this strain
for 1 minute; and [0372] d) pull to 50% strain at a constant rate
of 10''/min (254 mm/min)--second cycle load [0373] e) hold at that
strain for 30 seconds and return to 0% strain at the same crosshead
speed--second cycle unloading [0374] From the data collected in
step 5, the following two measurements are used: [0375] a) first
cycle force at 15% strain [0376] b) % set, which is defined as the
strain at 0.05N in the second loading cycle. The 0.05N force is
deemed sufficient to remove the slack but low enough to impart, at
most, insubstantial stretch to the sample. [0377] 6. Record data
for first cycle load at 15% strain [0378] 7. Record data for % set.
Air Permeability
[0379] Air permeability is determined by measuring the time in
which a standard volume of air is drawn through a test specimen of
a defined area at a constant pressure and temperature. This test is
particularly suited to materials having relatively high
permeability to gases, such as nonwovens, apertured films and the
like. The air permeability test is performed according to ASTM
D737-96 entitled "Standard Test Method for Air Permeability of
Textile Fabrics" with the following test parameters. A TexTest
FX3300 instrument is used. (Available by Textest AG in Switzerland
(www.textest.ch), or from Advanced Testing Instruments in
Spartanburg S.C., USA.) The test is conducted in a laboratory
environment at about 22.+-.2.degree. C. and about 50% relative
humidity. The test pressure drop is 125 Pascal and the test area is
38 cm.sup.2. In this test, the instrument creates a constant
differential pressure across the sample which draws air through the
sample. The rate of air flow through the sample is measured in
ft.sup.3/ft.sup.2/min (often called cfm or ft/min) or
m.sup.3/m.sup.2/min (or m/min). For each sample, three replicates
should be run, and the average result is reported.
Hydrostatic Head (Hydrohead) Pressure
[0380] The property determined by this test is a measure of the
liquid barrier property (or liquid impermeability) of a material.
Specifically, this test measures the hydrostatic pressure the
material will support: when a controlled level of water penetration
occurs. The hydrohead test is performed according to EDANA 120.2-02
entitled "Repellency: Hydrostatic Head" with the following test
parameters. A TexTest Hydrostatic Head Tester FX3000 (available
from Advanced Testing Instruments, Corp., Spartanburg, S.C., or by
Textest AG in Switzerland (www.textest.ch)) is used. For this test,
pressure is applied to a defined sample portion and gradually
increases until water penetrates through the sample. The test is
conducted in a laboratory environment at about 22.+-.2.degree. C.
temperature and about 50% relative humidity. The sample is clamped
over the top of the column fixture, using an appropriate gasketing
material (o-ring style) to prevent side leakage during testing. The
area of water contact with the sample is equal to the cross
sectional area of the water column, which equals 28 cm.sup.2. Water
is pumped into the water column at a rate of 20 mbar/min. Thus, the
sample is subjected to a steadily increasing water pressure on one
surface. When water penetration appears in three locations on the
other surface of the sample, the pressure (measured in mbar) at
which the third penetration occurs is recorded. If water
immediately penetrates the sample (i.e., the sample provided no
resistance), a zero reading is recorded. For each material, three
specimens are tested and the average result is reported.
[0381] In various embodiments of the present disclosure, an
absorbent article with an anchoring system can have a backsheet, an
absorbent core and a topsheet, provided with at least one opening
adapted to receive fecal material, said topsheet and said opening
thereof each having a front region and a back region, characterized
in that said diaper comprises a genital coversheet, which in use
covers the genitals, and which is positioned in, under or above
said front region of the opening, whereby a void space is formable
between the genital coversheet and the absorbent core, and whereby
a void space is present between the topsheet and the absorbent
core. Thus, the genital coversheet reduces the size of the
opening.
[0382] Such a genital coversheet is typically urine permeable, so
that the urine can pass through it immediately to the absorbent
core of the diaper, and it preferably has a low rewet, so that the
amount of urine passing back to the genitals is minimized. In
another embodiment, an absorbent article, typically an adult or
infant diaper or training pants comprising a backsheet, includes an
absorbent core and a topsheet, and integral therewith a genital
cover portion, said topsheet having a front region and a back
region, and said topsheet comprising in part of said front region
and part of said back region back region an opening, preferably a
single opening, to receive fecal material, characterized in that
said topsheet comprises in the front region a genital cover portion
that is urine permeable (and that preferably can form a pocket
and/or has the extendibility described herein for the genital
coversheet) and that the topsheet comprises in the back region an
urine-impermeable and feces-impermeable feces-retaining portion,
having a mean pore size of less than 20 microns and a
air-permeability of at least 3 Darcy, whereby there is a void space
between the genital-cover portion of the topsheet and the absorbent
core and between the feces-retaining portion of the topsheet and
the absorbent core.
[0383] In various embodiments, an absorbent article with an
anchoring system of the present disclosure can also be configured
as described in U.S. Pat. No. 6,482,191, which is hereby
incorporated by reference.
Theory of Anchoring:
[0384] Those skilled in the art of absorbent articles will
appreciate that the size and shape of the wearer has a substantial
impact on the comfort and performance of an article in use.
Absorbent articles are typically sized to fit a given segment of
the human population and a range of sizes is offered to cover each
target market for the product (such as infants, toddlers, small
children or adults). Each size is intended to provide comfort and
performance for all the wearers in the segment it is designed to
fit. Anchoring is particularly sensitive to the shape and size of
the wearer.
[0385] The present invention provides anchoring systems that are
more robust across a size segment than the present art.
Nevertheless, absorbent articles have many design tradeoffs and
interactions which often lead to unintended and unexpected results
from seemingly innocuous changes to a product design. While not
wishing to be bound by theory, the inventors offer a theory herein
to explain the principles behind various aspects of the present
invention.
[0386] To help with description of locations on the wearer's body,
a coordinate system for the wearer is defined. Detailed numerical
coordinates need not be used in this disclosure, but the coordinate
axes will provide the ability to qualitatively discuss relative
locations. It is convenient to use the pelvis to base a coordinate
system because the anchoring systems described herein are intended
to remain in a fixed position about the pelvis. Note that the waist
and leg perimeters of the diaper will contact surfaces of the body
which are driven by the spine and legs and can move relative to the
pelvis. Thus the body surfaces surrounding the spine and legs move
and deform somewhat independently of the surface surrounding the
pelvis. Thus during wear, the diaper perimeters at the waist and
legs may move relative to the anchoring system of the present
invention.
[0387] Referring to FIG. 21, the coordinate system is established
relative to the pelvis as it is positioned in a baby standing
upright. A baby is used as an exemplary wearer but the principles
illustrated and described herein apply to all human wearers. The
origin of the coordinate system is the center of gravity of the
pelvis. The "y" axis is vertical (in line with gravity) with the
positive direction pointing up. The "x" axis is oriented in the
wearer's left-to-right direction with positive direction pointing
to the wearer's left (thus when viewing the wearer from the front,
positive "x" is toward the right). The "z" axis is in the
front-to-back direction with the positive direction toward the
front.
[0388] Unless stated otherwise, the wearer is assumed to be
standing in the following description of the theory. It is also
assumed that wearable articles are held in place on the body by the
physics of mechanical contact. This limits the possible
interactions between the wearer's body and the article to normal
force and friction. The present invention is fully compatible with
any method to favorably enhance the interaction in contact areas
such as body adhesives and the like, but these are ignored during
the discussion of theory.
[0389] From the moment a diaper is put on a body, various forces
arise within the diaper and between the diaper and body. These
forces come from many sources such as the initial taping forces,
diaper mass, body movement, urination, bowel movements, and
physical interaction with clothes and parents. The weight of an
absorbent article can generate significant force in the negative y
direction (downward) as it collects and stores bodily wastes. For
example, a diaper designed for a toddler may weigh 50 grams
initially when dry and typically 100 to 200 grams when changed. If
the toddler were standing, this load force would tend to drag the
diaper down the body unless there was an equal upward support
reaction imposed on the diaper. Another important load force comes
from deceleration that occurs from the impact of the feet hitting
the floor when the toddler runs or jumps. The deceleration of the
body would tend to drag the diaper down the body unless there was
an equal upward support reaction generated on the diaper which
decelerates at the same rate that the body decelerates so that the
diaper will not move down the body. These two load forces are the
target loads for the anchoring system of the present invention.
[0390] Load forces originating from the weight of the absorbent
article typically originate in the lower half of the article;
however, locations on the body that can successfully create support
reactions (i.e., can support the load forces) are typically engaged
by the upper half of the article. It therefore follows that a
system designed to anchor the article may have to perform various
functions such as, for example: 1) collecting load forces, 2)
transmitting the load forces to parts of the body surface favorable
for creating support reactions, and 3) arranging the load forces so
that sufficient support reactions are generated.
[0391] One feature that distinguishes the various aspects of the
present invention from the prior art is that these functions are
carried out by an anchoring system made up of a network of
anchoring bands and load distribution elements. Another feature
includes the reduction of load stresses on other parts of the
article. For example, the inclusion of a BSOC may reduce the
tendency for the wearer's movement to also induce movement in the
waist and leg perimeters of the article. Additionally, by reducing
force transmission from the core assembly through the outer cover,
the materials selected for the outer cover may include
elastic/extensible materials which can provide an underwear like
look and feel to the article while also delivering comfort and fit
to the wearer.
[0392] Further, these networks can direct the load forces to the
most desirable areas of the body for support in the most desirable
directions that all together provide the needed support at the
lowest tension and therefore maximum comfort.
[0393] Regarding the first role of the anchoring system, the theory
assumes that the load forces are already collected and presented to
the anchoring system as point sources. For those embodiments that
have a core assembly such as 23 in FIG. 1A, there is sufficient
structural support for the absorbent core so that the load forces
arising from the distributed mass of the core and its contents can
be "collected" to a few attachment points on the assembly. These
attachments points can be designed to withstand the rigors that
concentrated loads place on them. Those skilled in the art would
recognize that other core structures may include a functionally
equivalent structure to the containment member 28 in FIG. 1B to
serve to collect the load forces so that attachments for
transmitting the loads to the anchoring system will not destroy the
attachment or core integrity during wear.
[0394] Regarding the second role, the transmission of load forces
can be modeled in theory by abstract curved lines with no weight,
width, thickness, or bending stiffness but possessing the axial
properties of an ideal spring thus the ability to carry loads in
tension. These theoretical "springs" are termed "load bands" or
"force bands" herein. Loads are transmitted by load bands to those
areas of the body that are suitable for creating support reactions.
A load band has a length, a spring constant, and a connection point
at each end. Connection points are endpoints of the load band which
can be connected to other load bands or a load. Loads and other
load bands that meet at a given connection point are free to rotate
about the connection point without resistance in any direction
except for the barrier imposed by the body surface.
[0395] Regarding the third role, anchoring can be described in
terms of a load force inducing an opposing support reaction.
Therefore areas of contact between the body and the anchoring
system where the load forces and opposing support reactions meet
are termed anchoring zones. The theory considers three different
modes in which the body can generate support reactions in response
to a load force in the anchoring zones. Each mode has a different
relationship between the direction of the load force and the
direction of support reaction. To some degree the three modes are
complimentary, which in a properly engineered anchoring system,
creates a more robust system than reliance on a single mode. The
modes are termed "frictional", "geodesic", and "geometric". All
three anchoring modes depend, at least in part, on the generation
of a normal force when flexible materials are wrapped in tension on
a curved surface. Geometric anchoring additionally uses stored
elastic energy to create support forces.
[0396] In general, solid bodies that contact each other interact
only by normal force and friction. A normal force is one that is
directed perpendicular to the surface of contact. Friction is a
force generated parallel to the surface of contact in response to a
sliding force between the bodies to Friction requires normal force
in order to operate. Thus a normal force is required for any type
of support interaction in the anchoring zone. Since an anchoring
zone is a contact zone, the load force transmitted to the anchoring
band arrives at the anchoring zone parallel (tangential) to the
surface of contact. A normal force forms in this anchoring zone if
the surface of contact has a convex curvature in the axial
direction of the anchoring band.
[0397] FIG. 36 shows an element of an anchoring band in an
anchoring zone. The anchoring zone is depicted as a layer of diaper
material 3602 tensioned over a curved element of the body. Only an
outside layer of skin 3603 is represented. As shown in FIG. 36, the
anchoring zone is the surface interface between the layer of diaper
material and outside layer of skin. The band is tensioned along an
axis indicated by T.sub.1 and T.sub.2. The tension and curvature
cause a normal force/unit area, F, to form at every point there is
tension and curvature. The body-side surface of the anchoring zone
responds to F with a support reaction, R.sub.N, of equal magnitude,
which is also normal 3601 to the surface, but in the opposite
direction. For clarity, the forces are shown only at point P.sub.0,
but integrating the force per unit area across the area will give a
total normal force on the surface element. The normal force at a
given point is proportional to the curvature of the surface and
proportional to the tension in the band at that point.
[0398] The principles of geodesic and geometric anchoring are more
easily described in the absence of friction, so with regard to the
discussion pertaining to geodesic and geometric anchoring, an
assumption is made that frictional forces are zero.
[0399] As stated previously, in theory, a force band may act as an
ideal spring. When stretched across a curved surface between two
points, the force band will seek a path that minimizes its
potential energy. The potential energy of a spring being
proportional to its stretched length, a stretched force band takes
an equilibrium path that is the shortest path between the two
points. The shortest path between two points on a curved surface is
mathematically defined as a "geodesic". The geodesic formed between
two points is called an "open" geodesic.
[0400] Some of the relevant properties of geodesics as defined by
generally accepted mathematics will be used herein to describe the
application of geodesic principles to the anchoring systems of the
present invention. More information on geodesics and their
mathematical properties can be found in texts on differential
geometry and the theory of general relativity, for example, Barrett
O'Neill, Elementary Differential Geometry Ch. 7 (Academic Press
2006); and James Foster & David J. Nightingale, A Short Course
in General Relativity Ch. 2.1 (Springer Science and Business Media
2006).
[0401] On a convex, frictionless surface, a force band in tension
will follow a geodesic path. The two points that define the force
band are termed "endpoints". If the region between two endpoints on
a surface contains a concave area, a force band under tension can
bridge the concave area. The portions of the path that the force
band contacts will be geodesics, and the portions of the force band
spanning the contacted portions of the path will also be a geodesic
because it is a straight line in space. In contrast, a mathematical
geodesic would be forced to follow the concave surface and would
not be able to bridge (span) the concave surface. Thus a
mathematical geodesic would have a longer path than the force band
where the shortest distance between the two endpoints included a
concave surface. Although they are used in a similar fashion here,
a geodesic is a geometric concept that has no means to carry
tension; and a force band does. This explains why a force band
bridges a concave region of a surface and a geodesic doesn't.
[0402] Force bands have some very useful properties for
constructing anchoring systems because they follow geodesic surface
pathways and because they carry tension. These properties have a
direct bearing on how the anchoring system works. In the following
discussion the surface is assumed to be a convex curved surface. In
general what applies to a mathematical geodesic on a convex surface
also applies to a force band on a surface with concave regions. Key
aspects of mathematical geodesics as they relate to anchoring
systems include: [0403] 1. The mathematical definition of a
geodesic allows one to extend a geodesic beyond the two points that
originally defined it, i.e., mathematically, a geodesic has no end
other than where it intersects the edge of a bounded surface. For
many closed surfaces, the extended geodesic may intersect itself
forming a closed geodesic. FIGS. 22 and 23 show force bands on open
and closed geodesics, respectively. [0404] 2. A closed geodesic may
form an angle, .gamma., where it intersects itself (called a
"corner"). Note that geometrically, only the circumferential path
turns the corner. Both ends of the geodesic path theoretically
continue straight through the corner and follow the mathematic
definition of a geodesic as long as there is surface. In schematic
anchoring systems, force bands typically end at the corner and the
geodesic extensions are truncated and replaced by a single vector
representing a load force. The corner itself is considered a
connection point 548 where a load force or another force band can
be attached (shown in FIG. 23). [0405] 3. A force band under
tension following a closed geodesic, but with no load connections
may form a continuous smooth curve with no corner (therefore
.gamma.=.pi. radians). This condition is a shortest closed path. A
closed geodesic with a corner has a longer path compared to a
closed geodesic that passes through the corner at .gamma.=.pi..
[0406] 4. Another consequence of the mathematical definition of
geodesics is that the only force a tensioned force band places on a
frictionless surface is normal to the surface. For this reason
anchoring by normal force is termed the "geodesic anchoring mode".
[0407] 5. The geodesic path does not depend on tension, i.e.,
increasing the tension of a force band has no tendency to change or
"straighten the path. In this sense, the geodesic on a curved
surface is an exact analog of a straight line in Euclidean space.
[0408] 6. In the absence of friction, force bands may arrange
themselves so they are loaded tangent to the endpoints. This is
also termed "axial" loading. If the direction of a load placed on
one endpoint changes, that endpoint will move until a new path is
established tangent to the new loading direction (in the absence of
friction). [0409] 7. All straight lines in a plane are geodesics.
In FIGS. 37-39, force bands are conveniently drawn as straight
lines and the surface is planar. However, the following statements
that refer to straight lines on a plane also hold for force bands
on a curved surface. [0410] 8. A load attached to a force band in
between endpoints at any angle other than 0 degrees or 180 degrees
(i.e. tangential, in line with the axis) causes a new geodesic
endpoint to form. Referring to FIG. 37, a force band is formed by
points 1 and 2 that are fixed to a surface (endpoints are shown as
circles). A load is attached to the force band at point 3 thereby
forcing the force band off its geodesic path and creating a corner.
The corner is regarded as a connection point dividing the force
band's original geodesic path into two new ones and creating a
force equilibrium with the load force. The two force bands formed
between points 1 and 3 and between 3 and 2 lengthen until the
magnitude of their vector sum is equal to the load. If the surface
is curved, the vector directions would be tangent to the geodesics.
The geometry will adjust until each force band is loaded axially. A
corollary to this is that two force bands connected to each other
at their endpoints will form a single new force band following the
geodesic path between the unconnected endpoints. Note: endpoints
and connection points are essentially the same thing except that
"connection point" emphasizes that force is being transmitted
between force bands. [0411] 9. Referring to FIG. 38, when two point
loads are added to a force band, the original force band can be
broken into 3 geodesics. In order for the forces to balance around
the connection point, the length (and therefore the tension) of all
3 force bands increases. [0412] 10. Referring to FIG. 39, if
instead of point load connections, the load was distributed
continuously along a portion of the force band, the original force
band can be broken into 2 geodesic segments and a non-geodesic
segment. The load is distributed continuously between points 3 and
4. Segments between points 1 and 3 and between 4 and 2 follow
geodesics. The segment between points 3 and 4 is a non-geodesic
force band that has been pulled away from the surface geodesic
between point 3 and 4 (represented by the thin straight dashed line
connecting them). FIG. 40 shows what happens in an element of the
anchoring zone, assuming there is contact and curvature. FIG. 40
shows an element of an anchoring band in an anchoring zone. The
anchoring zone is depicted as a layer of diaper material 4002
tensioned over a curved element of the body. Only an outside layer
of skin 4003 is represented. The effect of a distributed load, L,
is to shift the force, F, created on the surface away from the
normal 4001. F therefore has a normal component, F.sub.N, and a
tangential component, F.sub.T, along the surface perpendicular to
the axis of the tension in the segment (between T.sub.1 and
T.sub.2). In other words, when a distributed load pulls a force
band off of its geodesic, the original normal force becomes tilted
and the article side of the element gains a tangential component to
counter the load. This tangential force is termed the "geometric
anchoring force". The geometric anchoring force comes from stored
elastic energy created as the load pulls the force band off a
geodesic path. Note that the geometric anchoring force does not
come from the body. In fact, the load force for this portion of the
load is transmitted to another site in the anchoring system where
geodesic anchoring occurs and a normal support reaction is
generated. Thus "geometric anchoring" is actually a means to
redirect loads to a location more suitable for geodesic
anchoring.
[0413] The force bands described above can be configured into
geodesic networks that can be tailored for specific applications.
These networks may be represented as anchoring "schematics" that
indicate the configuration of elements of the network. Each element
in an anchoring schematic indicates the function that is to be
carried out by an analogous element in the physical anchoring
system. As used herein, anchoring schematics are shown in a
perspective view on a wearer's body to indicate the approximate
body location for each function. Any physical embodiment may be
used to carry out the function as long as it can perform as desired
in the location indicated and be successfully connected the other
elements in the system. Anchoring schematics have only three
different elements--force bands, connection points, and load
forces. Force bands are represented by geodesic curves. Load forces
are represented by force vectors that indicate the line of action
of the load as expected in the physical embodiment while in use.
Connection points are the idealized junctions between force bands
and the means of attaching load forces to the network. Connection
points are designated hereafter as item 548. Force bands and load
forces attached to connection points communicate forces with each
other and are free to rotate in all directions about the connection
point. The only constraint is that none of the elements is allowed
to penetrate the wearer's surface. Networks are assumed to be in
equilibrium, which in some cases implies that each force band is in
tension.
[0414] The human surface used in the schematics presented herein is
intended to represent a typical walking baby between 12 and 24
months. Force bands are shown to be in the approximate geodesic
location of this typical user of absorbent diapers but it should be
appreciated that surface geometry is somewhat different in humans
at different stages of growth and maturity. Once there is knowledge
of where the geodesics in the schematics reside on a target wearer,
the elements for a physical anchoring system can be sized and
placed from the schematic and fabricated.
[0415] The simplest element of an anchoring system is a force band
that follows an open geodesic path. FIG. 22 is a schematic of an
open geodesic 549 between a point 548 in the center of the front
and a point 548 in the center of the back of the baby. Force
vectors 551 and 551' of equal magnitude, each tangent to its
respective endpoint, represent either load forces acting on the
force band or tension from another connected force band.
[0416] On a frictionless, but otherwise real baby, the tensioned
load band would automatically adjust to follow a geodesic. If the
tension were increased, the path could change slightly as the baby
surface deforms in response to the increased normal force in the
curved areas, but the path would remain stable. Schematics are
assumed to be at their equilibrium geometry. It should be
appreciated that in a physical embodiment of an open force band,
efforts should be made to maintain substantially equal tension at
both ends in order to prevent the band from moving along the
geodesic path--i.e., sliding axially across the wearer's skin.
[0417] Load forces acting at the endpoints are anchored by support
reactions occurring everywhere along the band where there is
contact, tension, and curvature. Therefore most of the contact area
under the band is considered an anchoring zone. However the amount
of support provided varies within the anchoring zone. One reason is
that the magnitudes of support reactions vary with surface
curvature. The second reason is that the force balance on the
system requires the sum of the reactions be equal and opposite to
the sum of the load forces. Thus only the reaction components in
the same direction as the vector sum of the load forces will
support the load. It then follows that the portions of the
anchoring zone that provides the most support are those that have a
high curvature surface and are the most perpendicular to the vector
sum of the loads of each force band. Thus in the case of the open
load band in FIG. 22, most of the anchoring occurs over the hips
where the surface has high curvature and is mostly perpendicular to
the sum of the loads (the loads and their sum are all substantially
parallel).
[0418] If the wearer is standing upright, most of the load forces
to be anchored are substantially vertical. Therefore the valuable
geodesics for anchoring are those that pass over surfaces with a
horizontal component (and therefore the surface normal has a
vertical component). Some portions of the body surface can be
roughly conical. These surfaces can be characterized by their "cone
angle" which is the angle that straight lines on the surface
emanating from the theoretical apex of the cone make with the
vertical axis of the cone. The larger the cone angle the flatter
the cone and the larger the horizontal component of the surface.
The un-deformed surface of the naked human has geodesics that have
sufficient cone angles and curvature in places suitable for
anchoring. These places tend to be at the sides of the body in the
hip region. Because the geodesics passing over such surfaces
produce normal force, the body compresses. If the body has
compressibility gradients in y-direction, a roughly horizontal band
with a width will tilt in at the top and enhance the cone angle and
thus the amount of anchoring that can occur increases at a given
tension. When a bone is relatively close to the surface, an
anchoring band just above the bone in the y-direction will see a
compressibility gradient in an advantageous direction and the cone
angle will increase. Boney prominences that are particularly useful
in anchoring are the iliac crest (of the pelvis) and the greater
trochanter (of the femur).
[0419] By itself, this horizontal open force band may not perform
useful anchoring because the surfaces it passes over are
substantially vertical. However, by making sure the geodesic passes
over areas with a good compression gradient and thus getting the
benefit of a large cone angle, the endpoints could be rotated
downward and produce a greater potential for anchoring. With
endpoints rotated down, the force band will possess a favorable
vertical component in the front and back can be directly used to
anchor vertical loads in the front and back. By itself this force
band may not be stable on its geodesic because there is no means to
couple a vertical load into the force band axially.
[0420] To overcome this, open geodesics can be combined into
networks. For instance, FIG. 24A illustrates two mirror image open
force bands 549 and 549' connected in the center of the wearer's
front and back. If equal downward loads are attached to the
connection points 548, a stable system can be achieved. The loads
can be arranged so that they split equally between, and act
tangentially on, the ends of the force bands 549 and 549'. For
example, this will happen if the load forces bisect the angle
between the two force bands at each connection point 548. The
over-the-hip geodesics illustrated in FIG. 24A may depend on
y-direction compressibility gradients to achieve a sufficiently
vertical component.
[0421] In contrast, closed geodesics may provide self-stability.
FIG. 23, for instance, illustrates a schematic of a typical closed
geodesic force band 544 on a baby. When .gamma.<.pi., the
geodesic intersection (corner) is the ideal connection point 548
for loads. When the load is attached to the connection point 548,
equal loads at both ends of the geodesic can occur. The closed
geodesic force band 544 may automatically shift as needed to keep
the load equally distributed to both ends of the band.
[0422] When the system anchors geodesically, the tension in the
force band is a function of load, L (the vector 551 pointing
downward) and the corner angle, .gamma.. Tension, T, in the band
equals L/(2 cos .gamma./2). From this equation it can be observed
that, as .gamma. approaches 0, the tension in the band approaches
L/2 (since the load splits evenly between the two ends), and is the
lowest theoretically possible. As .gamma..fwdarw..pi. (while
loaded), the tension theoretically approaches infinity. The value
of .gamma. can be controlled by the relaxed length and spring
constant of the force band. For example, .gamma. may decrease if
the relaxed length is made longer or the spring constant, k, of the
force band is made smaller. Reducing k, causes the force band to
stretch further for the same load. As .gamma. gets smaller, the
tension gets smaller, but the load connection point drops lower on
the body. Therefore there are significant design tradeoffs between
these parameters.
[0423] If .gamma.<.pi. there is potential for "slack" to form in
the load band during dynamic wear. This is because .gamma.<.pi.
implies that a shorter closed path exists. In dynamic wear
situations, it is possible for the load to be temporarily in free
flight and thus effectively reduce the load force to zero. It is
then possible that with motion the force band will move to that
shorter path and slack will form. With slack present it is possible
for the force band to be easily moved off the desired geodesic and
possibly cause it to fall off the wearer.
[0424] FIG. 25A shows two closed force bands, one band 544 to
support loads in the front and another band 544' to support loads
in the back. Independent front and back load supports can provide a
stable solution for situations where loads originating in the front
and back may be significantly different. The force band
configurations shown in FIGS. 24A and 25A depict the approximate
body location of four geodesics found to be useful in anchoring
systems. The exact locations of the geodesics vary somewhat between
groups at different stages of growth and maturity and between
individual wearers within groups.
[0425] With knowledge of the basic principles of geodesics and the
locations of useful body geodesics it can be appreciated that many
different theoretical anchoring configurations can be created from
force bands, connection points, and load forces toward particular
design objectives. These schematics can be embodied digitally or
physically and tested on virtual or real wearers as anchoring
systems attached to a core assembly.
[0426] In anchoring system schematics, load forces are depicted in
the figures only by their connection points and directions. By
convention the schematic provides connection points on the
anchoring system that anticipate matching connections on the core
assembly; therefore making it unnecessary to specify the load
forces further. A brief discussion follows of how some of the
schematic anchoring configurations contemplated by the present
invention are theoretically believed to work.
[0427] With regard to FIGS. 24A-33C, the "A" figures are the
functional schematic, the "B" figures are the physical embodiment
of the functional model, and the "C" figures are the physical
embodiment within an absorbent article. As such, the force bands
referred to hereafter represent the functional model for anchoring
bands and LDEs of the physical anchoring system.
[0428] A suitable configuration of an anchoring system constructed
in accordance with the present invention is shown in FIG. 24A. The
FIG. 24A configuration may comprise two over-the-hip force bands
549, 549' with centered load connections, front and back. This is
the simplest possible geodesic anchoring system. Anchoring occurs
primarily by the normal force generated over the hips 500. The
configuration is characterized by an angle, .gamma., at connection
point 548 which is defined exactly as in FIG. 23. As
.gamma..fwdarw..pi. this two geodesic system approaches a single
closed geodesic. As described earlier in regard to a closed
geodesic, there is a relationship between tension, load, and
.gamma.. T=L/(2 cos .gamma./2). An infinite tension causes .gamma.
to approach .pi. with a non-zero load.
[0429] However, the configuration of FIG. 24A can be subject to two
instabilities described previously. For example, in a frictionless
system, unequal front and back loads may cause the system to rotate
(e.g., from the front going down and back going up or vice-versa)
generally about the x-axis (shown in FIG. 8). In a physical
embodiment, friction will permit a difference in front and back
loads. As such, in some embodiments, the tension in the anchoring
bands can be increased by increasing .gamma.. The increase in
.gamma. will increase the tension in the anchoring bands thereby
increasing the friction which can widen the tolerance for unequal
loads. However, friction is not always dependable in dynamic
situations. As such, in some embodiments, load balancing can be
achieved by separately adjusting .gamma. between front and back by
changing the elevation of the connection points 548. This approach
may be particularly useful if the ratio of the front and back loads
remains fairly constant. Tension would be the same front and back
when the following condition is met. L 1 L 2 = cos .times. .times.
( .gamma. 1 / 2 ) cos .times. .times. ( .gamma. 2 / 2 )
##EQU1##
[0430] Note that changing .gamma. can change the geodesic path.
Another example of an instability comes from slack (also described
previously) in a dynamic system. The smaller .gamma. is, the longer
the total path length of the geodesics, and the larger the
potential slack. Potential slack has an advantage in pant products
because if .gamma. is low enough, the slack can be enough to allow
the pant to be pulled over the buttocks and hips without requiring
the anchoring bands to stretch. Of course, the downside of slack is
instability. Where .gamma. smaller, stability can be obtained by
providing low-force elastic structures designed to simply keep the
geodesics in place in the event of slack-caused a dynamic
excursion. In the present invention an elastic biaxial stretch
outer cover can serve the role. For stand-alone anchoring systems,
the following configuration can be used.
[0431] In some embodiments, an anchoring system constructed in
accordance with the present invention may be configured as shown in
FIG. 29A. The FIG. 29A configuration may comprise two over-the-hip
force bands 549, 549' with centered load connections 548, front and
back with an elastic stabilizing band 561. This configuration takes
care of the stability problem of the anchoring system of FIG. 24A
configuration by adding a low force closed elastic geodesic to
simply maintain the location of the anchoring bands in the event
they are slack during a dynamic excursion. Stabilizing bands are
joined to the geodesic force bands; however, there may be no
significant force balance to be considered at the attachment
points. In some embodiments, for example, in a pant, the elastic
stabilizing band 561 can easily stretch when the pant is pulled up,
but it would not have to carry a large portion if any of anchoring
load during wear.
[0432] In some embodiments an anchoring system constructed in
accordance with the present invention may be configured as shown in
FIG. 32A. The anchoring system of FIG. 32A may comprise two open
geodesic stabilizing bands 561, 561' instead of the single closed
geodesic of FIG. 29A. The stabilizing bands 561 and 561' may be
joined to the force bands 549 and 549'; however, no significant
force balance may need to be considered. Both stabilizing band
configurations of FIGS. 29A and 32A can work for stand-alone
anchoring systems.
[0433] In some embodiments, an anchoring system constructed in
accordance with the present invention may be configured as shown in
FIG. 25A. The FIG. 25A configuration may comprise two closed force
bands 544, 544' and centered load connections 548, front and back.
The closed geodesics are anchored in the same general area 500 over
the hips as the other systems described thus far. This system is
very stable particularly if operating with little or no slack. It
can be particularly effective where the article is a side-fastened
taped diaper. In some cases the center load connection points 548
may be too low on the core assembly (as may be the case for any
centered load connections). The load connection points 548 can be
raised using the configuration shown in FIG. 26A.
[0434] In some embodiments, the load connection points 548 can be
configured to provide two load connection points 548A and 548B that
are higher and outboard of the original location of the single
connection point 548 (shown in FIG. 25A). FIGS. 34 and 35 show how
the two configurations provide equivalent anchoring with different
load connections. FIG. 34 represents one of the closed force bands
544 with a center load connection 548. The force band is "cut" by a
horizontal line 501 above the original connection point 548 and
below the portion of the force band 544 where normal support
reactions occur 500 (shown in FIG. 25A). This creates two new
connection points 548A and 548B. In FIG. 35, a new single geodesic
550 reconnects the force band 544 at the new connection points 548A
and 548B and provides the means to resolve the horizontal
components of the tension in the remainder of the original force
band 544. The vertical load force may be split into two halves and
moved to the two new connection points 548A and 548B. At each
connection point 548A and 548B, the force band 544 and new load
force add vectorially so that the portion of force band 544 above
the "cut" line 501 may experience the same axial tension as before.
Any load connection point can be reconfigured as long as the parts
of the geodesic where the anchoring reactions take place are
unchanged and they remain axially loaded with the same tension.
[0435] In some embodiments, an anchoring system constructed in
accordance with the present invention may be configured as shown in
FIGS. 28A-28C. As shown in FIG. 28A, the anchoring system may
comprise two over-the-hip force bands 549, 549' similar to the FIG.
24A configuration but with raised connection points 548A, 548B,
548C, and 548D. The connection points 548A and 548B may be disposed
at the front of a wearer while the connection points 548C and 548D
may be disposed at the back of a wearer, when the anchoring system
is in use. The load connection points may be derived from the FIG.
24A configuration in the same way that the FIG. 26A configuration
was derived from the FIG. 25A configuration.
[0436] In some embodiments, an anchoring system constructed in
accordance with the present invention may be configured as shown in
FIGS. 30A, 30B, and 31A-31C. As shown in FIGS. 30A and 31A in some
embodiments, an anchoring system may comprise portions of the open
and closed geodesic configurations discussed with regard to FIGS.
24A and 25A. For example, an anchoring system may comprise two and
four load connection point versions of a hybrid of the closed and
open geodesic configurations of FIGS. 24A and 25A. These
configurations have 5 and 7 open geodesic force bands,
respectively. The creation of the extra connection points can
create two additional open geodesic force bands (550 and 550') in
FIG. 31A. They are distinguished from previous configurations by
pre-tensioned force bands made up of an upper open force band 546
in the back and two front open force bands 544, 544'.
Pre-tensioning (i.e. tension caused by the application process, not
by load forces) provides stability for the force bands and a
tension bias that improves geometric anchoring.
[0437] Once loads are applied (as illustrated), the geodesics that
meet at the side connection points form angles that balance the
forces in 546, 545' and 544'. The same can be true for the opposite
side of the body. Thus the geodesic paths of this configuration
will be slightly different than geodesics that run continuously
through this area of the body such as those of FIGS. 24A and 25A.
There are many practical advantages to this configuration. As in
most configurations, anchoring occurs primarily in the hip
regions.
[0438] In some embodiments, an anchoring system constructed in
accordance with the present invention may be configured as shown in
FIGS. 33A-33C. As shown, the FIG. 33A configuration may comprise a
single pre-tensioned circumference made up of four open force bands
570, 571, 572, 573 and a zone 574, 574' of distributed load force
over each hip. The schematic symbol for a distributed load force is
introduced in this figure. The idea behind this configuration is to
leverage the geometric anchoring mode. This load distribution is
not straight-forward to physically embody because there are no
loads nor pathways to loads directly below this area. In practice,
a structure is provided that can take loads diagonally from the
front and back, balance the horizontal components and distribute
the vertical components to the geodesic. Such loads would cause the
geodesic to move off its true geodesic path as has been previously
described. FIG. 33B shows a structure that approximates this
behavior.
[0439] A small amount of stretch can help geodesic stability and is
hence often desirable. On the other hand, increasing the length of
the force bands will change the geometry and run the risk that the
new geometry may not fall on desirable geodesics. There are many
ways to configure stretch in the anchoring system. One skilled in
the art will recognize that it would be useful to test theoretical
configurations incorporating stretch prior to engineering an
anchoring configuration into a complete product. Force bands can be
divided into sections with differing stretch properties. Often the
same amount of stretch in one section can have a lower impact on
geodesic geometry than in another.
[0440] If an anatomically accurate digital or physical mannequin is
available, schematics can be literally studied with systems of
strings, springs, and load weights. Each force band is simulated by
a string in series with a steel spring with a known constant.
Simple ways are devised to connect simulated force bands together.
Loads can be simulated by hanging weights. This allows the geodesic
stability response of the network to be studied and optimized for
the stretch placement and extension properties. Since stretch is
often employed to improve size range, this too can be easily
studied if different size mannequins or "virtual wearers" are
available.
[0441] In the case of anchoring systems implemented into taped
diapers, it is usually possible to select a force band section for
stretch that will have a minimum impact on geodesic geometry. For
example, in the FIG. 31A configuration the force bands 544 and 544'
between each side connection point and the front is a good place
for stretch. The connection point on the core could literally be
the landing zone for a fastener. A landing zone located along the
connecting geodesic across the core could provide sufficient
rigidity so that the weight of the core could be correctly directed
to the stretch anchoring band.
[0442] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm".
[0443] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference,
however the citation of any document is not construed as an
admission that it is prior art with respect to the present
invention. To the extent that any meaning or definition of a term
in this written document conflicts with any meaning or definition
of the term in a document incorporated by reference, the meaning or
definition assigned to the term in this written document shall
govern.
[0444] 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.
* * * * *