U.S. patent application number 14/844385 was filed with the patent office on 2016-03-17 for absorbent article comprising a topsheet/acquisition layer laminate.
The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to Andrea L. BENNER, Aniruddha CHATTERJEE, Adrien GRENIER, James T. KNAPMEYER, Jill Marlene ORR, Rodrigo ROSATI, John B. STRUBE.
Application Number | 20160074247 14/844385 |
Document ID | / |
Family ID | 54140723 |
Filed Date | 2016-03-17 |
United States Patent
Application |
20160074247 |
Kind Code |
A1 |
ROSATI; Rodrigo ; et
al. |
March 17, 2016 |
ABSORBENT ARTICLE COMPRISING A TOPSHEET/ACQUISITION LAYER
LAMINATE
Abstract
An absorbent article for personal hygiene comprises a
longitudinal axis, a transversal axis perpendicular to the
longitudinal axis, a liquid permeable topsheet, an acquisition
layer, a liquid impermeable backsheet and an absorbent core. The
absorbent core is located between the topsheet and backsheet and
comprises an absorbent material. a width of the acquisition layer
in a direction parallel to the transversal axis is less than the
width of the topsheet in a direction parallel to the transversal
axis. The absorbent article comprises a topsheet/acquisition layer
laminate comprising the liquid permeable topsheet and the
acquisition layer in a face to face relationship. The
topsheet/acquisition layer laminate comprises three-dimensional
protrusions extending from a plane of the topsheet/acquisition
layer laminate.
Inventors: |
ROSATI; Rodrigo; (Frankfurt
Am Main, DE) ; ORR; Jill Marlene; (Liberty Township,
OH) ; GRENIER; Adrien; (Frankfurt Am Main, DE)
; BENNER; Andrea L.; (Schwalbach, DE) ; KNAPMEYER;
James T.; (Cincinnati, OH) ; STRUBE; John B.;
(Okeana, OH) ; CHATTERJEE; Aniruddha; (Kelkheim,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Family ID: |
54140723 |
Appl. No.: |
14/844385 |
Filed: |
September 3, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62049516 |
Sep 12, 2014 |
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62049521 |
Sep 12, 2014 |
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62049408 |
Sep 12, 2014 |
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62049406 |
Sep 12, 2014 |
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62049404 |
Sep 12, 2014 |
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62049403 |
Sep 12, 2014 |
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62049401 |
Sep 12, 2014 |
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62049397 |
Sep 12, 2014 |
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62049392 |
Sep 12, 2014 |
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62210057 |
Aug 26, 2015 |
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62210005 |
Aug 26, 2015 |
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62210020 |
Aug 26, 2015 |
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62210014 |
Aug 26, 2015 |
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Current U.S.
Class: |
604/378 |
Current CPC
Class: |
A61F 2013/530131
20130101; A61F 2013/530007 20130101; A61F 13/51108 20130101; A61F
2013/5395 20130101; A61F 13/51104 20130101; A61F 13/537 20130101;
A61F 13/51 20130101; A61F 2013/530715 20130101; A61F 2013/15463
20130101; A61F 2013/4568 20130101; A61F 2013/427 20130101; A61F
2013/530481 20130101; A61F 2013/530489 20130101; A61F 2013/530175
20130101; A61F 13/45 20130101; A61F 2013/4587 20130101; A61F
13/55145 20130101; A61F 13/534 20130101; A61F 2013/5386 20130101;
A61F 2013/51377 20130101; A61F 13/51394 20130101; A61F 2013/51147
20130101; A61F 2013/51355 20130101; A61F 2013/5307 20130101; A61F
13/15707 20130101; A61F 2013/8497 20130101; A61F 13/15699 20130101;
A61F 2013/421 20130101; A61F 13/55105 20130101; A61F 2013/53472
20130101; A61F 13/5116 20130101; A61F 13/536 20130101; A61F 13/513
20130101; A61F 2013/15365 20130101; A61F 2013/51009 20130101; A61F
13/15723 20130101; A61F 13/55115 20130101; A61F 2013/15284
20130101; A61F 2013/51023 20130101; A61F 2013/53908 20130101; A61F
2013/51002 20130101; A61F 13/15203 20130101; A61F 13/535 20130101;
A61F 13/551 20130101; A61F 2013/15715 20130101; A61F 13/511
20130101; A61F 13/5121 20130101; A61F 13/53 20130101; A61F
2013/530664 20130101; A61F 2013/51007 20130101; A61F 2013/51092
20130101; A61F 2013/51026 20130101 |
International
Class: |
A61F 13/511 20060101
A61F013/511; A61F 13/53 20060101 A61F013/53; A61F 13/534 20060101
A61F013/534; A61F 13/513 20060101 A61F013/513 |
Claims
1. An absorbent article for personal hygiene comprising: a
longitudinal axis, a transversal axis perpendicular to the
longitudinal axis, a liquid permeable topsheet, an acquisition
layer, a liquid impermeable backsheet and an absorbent core,
wherein the absorbent core is located between the topsheet and
backsheet; wherein the absorbent core comprising an absorbent
material; wherein a width of the acquisition layer in a direction
parallel to the transversal axis is less than the a of the topsheet
in a direction parallel to the transversal axis; a
topsheet/acquisition layer laminate comprising the liquid permeable
topsheet and the acquisition layer in a face to face relationship,
wherein the topsheet/acquisition layer laminate comprises
three-dimensional protrusions extending from a plane of the
topsheet/acquisition layer laminate; wherein the three-dimensional
protrusions are formed from the fibers of the topsheet and the
acquisition layer, wherein a majority of the three-dimensional
protrusions each comprises a base forming an opening, an opposed
distal portion, and one or more side walls between the bases and
the distal portions of the majority of the three-dimensional
protrusions, wherein the base, distal portion and the one or more
side walls are formed by fibers such that the majority of the
three-dimensional protrusion has only an opening at the base; and
wherein the majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate have a measured protrusion
height of at least about 0.3 mm according to the Protrusion Height
Test Method; wherein the majority of the three-dimensional
protrusions of the topsheet/acquisition layer laminate have a
measured protrusion base width of the three-dimensional protrusions
of at least about 0.5 mm according to the Protrusion Base Width
Test Method; wherein the topsheet/acquisition layer laminate has a
liquid in topsheet value less than about 220 mg according to the
Liquid in Topsheet method; and wherein the absorbent article has a
total acquisition time which is less than about 400 s according to
the Flat Acquisition test method.
2. The absorbent article of claim 1 wherein a length of the
acquisition layer in a direction parallel to the longitudinal axis
is less than a length of the topsheet in a direction parallel to
the longitudinal axis.
3. The absorbent article of claim 1 wherein the liquid permeable
topsheet and the acquisition layer are in an intimate contact with
each other.
4. The absorbent article of claim 1 wherein the absorbent material
comprises at least about 80% of superabsorbent polymers, up to
substantially about 100% of superabsorbent polymers, by total
weight of the absorbent material;
5. The absorbent article of claim 1 wherein the absorbent core
comprises a core wrap enclosing the absorbent material, wherein the
core wrap comprises a top side facing the topsheet/acquisition
layer laminate and a bottom side facing the backsheet, wherein the
absorbent core comprises one or more substantially absorbent
material free area(s) through which a portion of the top side of
the core wrap is attached by one or more core wrap bond(s) to a
portion of the bottom side of the core wrap.
6. The absorbent article of claim 1 wherein the three-dimensional
protrusions of the topsheet/acquisition layer laminate protrude
generally towards the backsheet or generally towards the body of
the wearer when the absorbent article is in use.
7. The absorbent article of claim 1 comprising a distribution layer
comprising dry-laid fibers and/or a wet-laid fibrous structure
comprising wet-laid fibers located between the topsheet/acquisition
layer laminate and the absorbent core.
8. The absorbent article of claim 7 comprising a carrier layer
wherein the carrier layer is disposed between the
topsheet/acquisition layer laminate and the dry-laid fibers.
9. The absorbent article of claim 7 comprising a carrier layer
wherein the carrier layer is disposed between the dry-laid fibers
and the absorbent core.
10. The absorbent article of claim 1 wherein the absorbent article
is notionally divided into a front region, a back region and a
crotch region located between the front and back region, wherein
each of the front, back and crotch regions is 1/3 of the length of
the absorbent article in a direction parallel to the longitudinal
axis, wherein the acquisition layer in the topsheet/acquisition
layer laminate is positioned in the front region and at least
partially in the crotch region, or wherein the acquisition layer in
the topsheet/acquisition layer laminate is positioned in the back
region and at least partially in the crotch region.
11. The absorbent article of claim 1 wherein the topsheet and the
acquisition layer of the topsheet/acquisition layer laminate are
nested together, such that the three-dimensional protrusions of the
topsheet and of the acquisition layer coincide with and fit
together.
12. The absorbent article of claim 1 wherein one of the topsheet or
acquisition layer of the topsheet/acquisition layer laminate is
interrupted in the area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate such that the three-dimensional
protrusions of the respective other non-interrupted topsheet or
acquisition layer interpenetrate the interruptions of the topsheet
or of the acquisition layer.
13. The absorbent article of claim 1 wherein one of the topsheet or
acquisition layer of the topsheet/acquisition layer laminate
comprises one or more interruptions in the area of the
three-dimensional protrusions of the topsheet/acquisition layer
laminate such that the three-dimensional protrusions of the
respective other non-interrupted topsheet or acquisition layer at
least partially fit together with the three-dimensional protrusions
of the interrupted topsheet or interrupted acquisition layer.
14. The absorbent article of claim 1 wherein the topsheet and
acquisition layer of the topsheet/acquisition layer laminate
comprise one or more interruptions in the area of the
three-dimensional protrusions of the topsheet/acquisition layer
laminate and the three-dimensional protrusions of the topsheet
coincide with and fit together with the three-dimensional
protrusions of the acquisition layer, and wherein the interruptions
in the topsheet in the area of the three-dimensional protrusions of
the topsheet/acquisition layer laminate does not coincide with the
interruptions in the acquisition layer in the area of the
three-dimensional protrusions of the topsheet/acquisition layer
laminate.
15. The absorbent article of claim 1 wherein the
topsheet/acquisition layer laminate has a rewet value less than
about 220 mg according to the rewet method.
Description
RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application Ser. Nos.
62/049,516 (P&G 13530P), 62/049,521 (P&G 13531PQ),
62/049,408 (P&G CM4137FPQ), 62/049,406 (P&G CM4136FPQ),
62/049,404 (P&G CM4135FPQ), 62/049,403 (P&G CM4134FPQ),
62/049,401 (P&G CM4133FPQ), 62/049,397 (P&G CM4132FPQ), and
62/049,392 (P&G CM4131FPQ), all of which were filed on Sep. 12,
2014, and to U.S. Provisional Patent Application Ser. Nos.
62/210,005 (P&G 13971PQ), 62/210,014 (P&G 13972PQ),
62/210,020 (P&G 13973PQ), and 62/210,057 (P&G CM 4131P2Q),
all of which were filed on Aug. 26, 2015. The entire disclosures of
all of the above-referenced U.S. Provisional Patent Applications
are fully incorporated herein by reference.
FIELD OF THE INVENTION
[0002] An absorbent article for personal hygiene such as a baby
diaper, a training pant, a feminine hygiene sanitary napkin or an
adult incontinence product is provided. The absorbent article
comprises a topsheet/acquisition layer laminate.
BACKGROUND OF THE INVENTION
[0003] An absorbent article typically comprises a topsheet, a
backsheet, and an absorbent core disposed between the topsheet and
the backsheet. The absorbent article can further include an
acquisition layer and optionally a distribution layer. The
acquisition layer is able to receive the liquid bodily exudates
from the topsheet in order to temporary store them. Then, the
optional distribution layer can receive the liquid bodily exudates
from the acquisition layer and distribute and transfer them to the
absorbent core in order to make efficient the use of the absorbent
core. Such absorbent articles exhibit satisfactory fluid handling
properties.
[0004] Three-dimensional (3D) topsheets have been developed; see
for example U.S. Patent application US 2014/0121625 A1.
[0005] There still remains a need to further improve
three-dimensional topsheets.
[0006] There remains a need to develop a skin facing layer having a
three-dimensional structure for an absorbent article to provide a
soft skin facing layer having improved dryness perception and
improved fluid handling properties e.g. less rewet on the topsheet,
while the physical and perceptional comfort of the wearer as well
as the leakage prevention are still met.
SUMMARY OF THE INVENTION
[0007] An absorbent article for personal hygiene is provided and
comprises a longitudinal axis, a transversal axis perpendicular to
the longitudinal axis, a liquid permeable topsheet an acquisition
layer, a liquid impermeable backsheet and an absorbent core. The
absorbent core is located between the topsheet and backsheet. The
absorbent core comprises an absorbent material. A width of the
acquisition layer in a direction parallel to the transversal axis
is less than a width of the topsheet in a direction parallel to the
transversal axis. The absorbent article comprises a
topsheet/acquisition layer laminate comprising the liquid permeable
topsheet and the acquisition layer in a face to face relationship,
wherein the topsheet/acquisition layer laminate comprise
three-dimensional protrusions extending from a plane of the
topsheet/acquisition layer laminate. The three-dimensional
protrusions are formed from the fibers of the topsheet and the
acquisition layer. A majority of the three-dimensional protrusions
each comprises a base forming an opening, an opposed distal
portion, and one or more side walls between the bases and the
distal portions of the majority of the three-dimensional
protrusions. The base, distal portion and the one or more side
walls are formed by fibers such that the majority of the
three-dimensional protrusions has only an opening at the base. The
topsheet/acquisition layer laminate has a liquid in topsheet value
less than 220 mg or less than 200 or less than 180 mg or less than
120 mg or less than 80 mg according to the Liquid in Topsheet
method. The absorbent article has a total acquisition time which is
less than 400 s or less than 300 s or less than 250 s or less than
200 s or less than 150 s according to the Flat Acquisition test
method.
[0008] The majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate may have a measured protrusion
height of at least 0.5 mm according to the Protrusion Height Test
Method.
[0009] The majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate may have a measured protrusion
base width of the three-dimensional protrusions of at least 0.5 mm
according to the Protrusion Base Width Test Method.
[0010] A majority of the three-dimensional protrusions may be more
than 50% or more than 60% or more than 70% or more than 80% or more
than 90% or more than 95% or more than 98% of the three-dimensional
protrusions in the topsheet/acquisition layer laminate.
[0011] The topsheet/acquisition layer laminate may have a Topsheet
Load less than 0.7 g/g, preferably less than 0.5 g/g according to
the Liquid in Topsheet method.
[0012] The maximum interior width of the void area at the distal
portion may be greater than the protrusion base width of the base
of the majority of the three-dimensional protrusions. Measurements
of the protrusion base width of the base or the maximum interior
width of the void area at the distal portion can be made on a
photomicrograph at 20.times. magnification.
[0013] The fibers of the topsheet and acquisition layer in the area
of the three-dimensional protrusions of the topsheet/acquisition
layer laminate may substantially or completely surround the one or
more side walls of the majority of the three-dimensional
protrusions.
[0014] The majority of the three-dimensional protrusions may be
configured to collapse in a controlled manner such that each base
forming an opening remains open, and the protrusion base width of
each base forming an opening is greater than 0.5 mm after
compression according to Accelerated Compression Method.
[0015] The width of the acquisition layer of the
topsheet/acquisition layer laminate may not wider more than 40% of
the width of the distribution layer and/or more than 20% of the
width of the absorbent core.
[0016] The absorbent article may comprise gasketing cuffs.
[0017] The majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate may at least or only be present
in the area where the topsheet overlaps the acquisition layer in
the topsheet/acquisition layer laminate.
[0018] The majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate may be present in the area
which extends parallel to the transversal axis of the absorbent
article. The majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate may be present in the area
which extends parallel to the longitudinal axis of the absorbent
article, but which does not extend beyond the area where gasketing
cuffs is attached to the absorbent article. In that case, the
majority of the three-dimensional protrusions which are formed in
the topsheet of the topsheet/acquisition layer laminate, are formed
from the fibers of the topsheet.
[0019] The absorbent article may comprise the topsheet having a
first region of the topsheet and the acquisition layer having a
first region of the acquisition layer; wherein the concentration of
fibers in the first region of the acquisition layer and in the
distal ends of the majority of the three dimensional protrusions is
greater than the concentration of fibers in the side walls of the
majority of the three dimensional protrusions in the acquisition
layer; and wherein the concentration of fibers in the first region
of the topsheet and in the distal ends of the majority of the three
dimensional protrusions is greater than the concentration of fibers
in the side walls of the majority of the three dimensional
protrusions in the topsheet.
[0020] The absorbent article may comprise the topsheet having a
first region of the topsheet and the acquisition layer having a
first region of the acquisition layer; wherein the concentration of
fibers in the first region of the acquisition layer is greater than
the concentration of fibers in the distal ends of the majority of
the three dimensional protrusions in the acquisition layer; and
wherein the concentration of fibers in the first region of the
topsheet and the distal ends of the majority of the three
dimensional protrusions is greater than the concentration of fibers
in the side walls of the majority of the three dimensional
protrusions in the topsheet.
[0021] The absorbent article may comprise the topsheet having a
first region of the topsheet and the acquisition layer having a
first region of the acquisition layer; wherein the concentration of
fibers in the first region of the acquisition layer is greater than
the concentration of fibers in the side walls of the majority of
the three dimensional protrusions in the acquisition layer; and
wherein the concentration of fibers in the side walls of the
majority of the three dimensional protrusions in the acquisition
layer is greater than the concentration of fibers forming the
distal ends of the majority of the three dimensional protrusions in
the acquisition layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] While the specification concludes with claims particularly
pointing out and distinctly claiming the present invention, it is
believed that the same will be better understood from the following
description read in conjunction with the accompanying drawings in
which:
[0023] FIG. 1 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate wherein
the length of the acquisition layer is less that the length of the
topsheet according to the present invention with some layers
partially removed;
[0024] FIG. 2 is a transversal cross-section of the diaper of FIG.
1;
[0025] FIG. 3 is a transversal cross-section of the diaper of FIG.
1;
[0026] FIG. 4 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate wherein
the three-dimensional protrusions of the topsheet/acquisition layer
laminate are only formed where the topsheet overlaps the
acquisition layer in the topsheet/acquisition layer laminate,
according to the present invention with some layers partially
removed;
[0027] FIG. 5 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate with
another type of absorbent core according to the present invention
with some layers partially removed;
[0028] FIG. 6 is a transversal cross-section of a diaper of FIG.
5;
[0029] FIG. 7 is a transversal cross-section of the absorbent
article of FIG. 5 taken at the same point as FIG. 6 where channels
have formed as a result the absorbent article being loaded with
liquid bodily exudates;
[0030] FIG. 8 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate with a
carrier layer according to the present invention with some layers
partially removed;
[0031] FIG. 9A is a transversal cross-section of the diaper of FIG.
8;
[0032] FIG. 9B is another transversal cross-section of the diaper
of FIG. 8;
[0033] FIG. 10 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate with a
carrier layer according to the present invention with some layers
partially removed;
[0034] FIG. 11 is a transversal cross-section of the diaper of FIG.
10;
[0035] FIG. 12 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate with an
acquisition layer positioned in a front region of the absorbent
article according to the present invention with some layers
partially removed;
[0036] FIG. 13 is an absorbent article in the form of a diaper
comprising an exemplary topsheet/acquisition layer laminate with an
acquisition layer positioned in a rear region of the absorbent
article according to the present invention with some layers
partially removed;
[0037] FIG. 14A is a perspective view of an apparatus comprising a
first and second forming member for forming the
topsheet/acquisition layer laminate of the present invention;
[0038] FIG. 14B is a perspective view of a portion of the first
forming member of the apparatus shown in FIG. 14A;
[0039] FIG. 14C is a perspective view of the apparatus shown in
FIG. 14A, showing the first forming member intermeshing the second
forming member;
[0040] FIG. 15A is a perspective view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0041] FIG. 15B is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0042] FIG. 15C is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0043] FIG. 15D is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0044] FIG. 15E is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0045] FIG. 15F is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0046] FIG. 16A is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0047] FIG. 16B is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0048] FIG. 16C is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0049] FIG. 16D is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0050] FIG. 16E is a schematic view of a three-dimensional
protrusion of the topsheet/acquisition layer laminate obtained with
the apparatus shown in FIG. 14A;
[0051] FIG. 17 shows an equipment assembly used in the Flat
Acquisition Test Method;
[0052] FIG. 18 shows an equipment assembly used in the Post
Acquisition Collagen Rewet Test Method;
[0053] FIG. 19 shows an equipment assembly used in the Fixed Height
Frit Absorption (FHFA) Test Methods.
DETAILED DESCRIPTION OF THE INVENTION
Definition of Terms
[0054] The term "absorbent article" as used herein refers to
disposable products such as diapers, pants or feminine hygiene
sanitary napkins and the like which are placed against or in
proximity to the body of the wearer to absorb and contain the
various liquid bodily exudates discharged from the body. Typically
these absorbent articles comprise a topsheet, backsheet, an
absorbent core and optionally an acquisition layer and/or
distribution layer and other components, with the absorbent core
normally placed between the backsheet and the acquisition system or
topsheet. The absorbent article of the present invention may be a
diaper or pant.
[0055] The term "diaper" as used herein refers to an absorbent
article that is intended to be worn by a wearer about the lower
torso to absorb and contain liquid bodily exudates discharged from
the body. Diapers may be worn by infants (e.g. babies or toddlers)
or adults. They may be provided with fastening elements.
[0056] The term "pant" as used herein refers to an absorbent
article having fixed edges, a waist opening and leg openings
designed for infant or adult wearers. A pant is placed in position
on the wearer by inserting the wearer's legs into the leg openings
and sliding the pant-type absorbent article into position about the
wearer's lower torso. A pant may be preformed by any suitable
technique including, but not limited to, joining together portions
of the absorbent 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).
[0057] The term "extensible" as used herein refers to a material,
which, upon application of a force, is capable of undergoing an
apparent elongation of equal to or greater than at least 100% of
its original length in the machine and/or cross-machine directions
at or before reaching the breaking tensile force if subjected to
the following test:
[0058] The MD and CD tensile properties are measured using a method
using WSP 110.4 (05) Option B, with a 50 mm sample width, 60 mm
gauge length, and 60 mm/min rate of extension.
[0059] It may be desirable that a material is capable of undergoing
an apparent elongation of equal to or greater than at least 100% or
110% or 120% or 130% up to 200% in the machine and/or cross-machine
directions at or before reaching the breaking force according to
the Test Method as set out above.
[0060] If a material is capable of undergoing an apparent
elongation of less than 100% of its original length if subjected to
the above described test, it is "non-extensible" as used
herein.
[0061] The term "topsheet/acquisition layer laminate" as used
herein refers to an intimate combination of a topsheet with an
acquisition layer, both disposed in a face to face relationship.
The topsheet has a first and second surface. The first surface of
the topsheet is facing towards the body of the wearer when the
absorbent article is in use. The acquisition layer is facing the
backsheet. The topsheet and the acquisition layer can have
undergone a simultaneous and joint mechanical deformation while the
topsheet and the acquisition layer are combined with each other.
The topsheet/acquisition layer laminate comprises deformations
forming three-dimensional protrusions.
[0062] In the topsheet/acquisition layer laminate, the topsheet and
acquisition layer may be in an intimate contact with each
other.
[0063] The topsheet/acquisition layer laminate may be formed by
nesting together the topsheet and acquisition layer, wherein the
three-dimensional protrusions of the topsheet coincide with and fit
together with the three-dimensional protrusions of the acquisition
layer, as shown in FIGS. 15A, 15B and 16A. The topsheet/acquisition
layer laminate comprises deformations forming three-dimensional
protrusions.
[0064] Alternatively or in addition to what has been set out above,
the topsheet/acquisition layer laminate may be formed by
interrupting one of the topsheet or acquisition layer such that the
three-dimensional protrusions of the respective other
non-interrupted topsheet or acquisition layer interpenetrate the
interrupted topsheet or acquisition layer, as shown in FIGS. 15C
and 16B.
[0065] In still another alternative or in addition to what has been
set out above, the topsheet/acquisition layer laminate may be
formed by interrupting one of the topsheet or acquisition layer in
the area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate such that the three-dimensional
protrusions of the respective other non-interrupted topsheet or
acquisition layer at least partially fit together with the
three-dimensional protrusions of the interrupted topsheet or
acquisition layer, as shown in FIGS. 15D, 15E, 16C and 16D.
[0066] In another alternative or in addition to what has been set
out above, the topsheet/acquisition layer laminate may be formed by
interrupting the topsheet and acquisition layer in the area of the
three-dimensional protrusions of the topsheet/acquisition layer
laminate and the three-dimensional protrusions of the topsheet
coincide with and fit together with the three-dimensional
protrusions of the acquisition layer. If the topsheet and
acquisition layer comprise interruptions in the area of the
three-dimensional protrusions, the interruptions in the topsheet in
the area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate will not coincide with the
interruptions in the acquisition layer in the area of the
three-dimensional protrusions of the topsheet/acquisition layer
laminate, as shown in FIGS. 15F and 16E.
[0067] The term "a majority of the three-dimensional protrusions"
as used herein means that more than 50% or more than 60% or more
than 70% or more than 80% or more than 90% or more than 95% or more
than 98% of the three-dimensional protrusions in the
topsheet/acquisition layer laminate of the absorbent article, each
comprises a base forming an opening, an opposed distal portion and
the one or more side wall between the base and the distal portion
of the three-dimensional protrusion. The base, distal portion and
one or more side wall are formed by fibers such that the
three-dimensional protrusion has only an opening at the base (as
exemplary shown in a FIG. 15A).
[0068] The term "interruptions", as used herein, refers to holes
formed in the topsheet and/or acquisition layer during the
formation of the topsheet/acquisition layer laminate, and does not
include the pores and interstices between fibers typically present
in nonwovens.
[0069] The term "mechanically deforming and combining" as used
herein means that the topsheet and acquisition layer are put in a
face to face relationship and can be simultaneously mechanically
deformed between a first and second roll and intimately combined at
the same time. The mechanical deformation of the topsheet and
acquisition layer depends on the process, the required apparatus
but also on the properties of the topsheet and acquisition layer,
i.e. apparent elongation of the fibers, fiber mobility, ability to
deform and stretch in the area where the three-dimensional
protrusions of the topsheet/acquisition layer laminate are formed,
ability to undergo plastic deformation which sets after existing
the first and second roll, or springing partially back due to
elastic recovery.
[0070] The mechanical deformation may comprise engaging the
topsheet and the acquisition layer together between a first and
second forming member such that a plurality of deformations
comprising three-dimensional protrusions are obtained. The
three-dimensional protrusions are formed form the fibers of the
topsheet and the acquisition layer. A majority of the
three-dimensional protrusions is defined by a base forming an
opening, an opposed distal portion and one or more side walls
between the base and the distal portion of the three-dimensional
protrusion. The base, distal portion and the one or more side walls
are formed by fibers such that the majority of the
three-dimensional protrusions has only an opening at the base, as
shown in FIG. 15A.
[0071] For the majority of the three-dimensional protrusions of the
topsheet/acquisition layer laminate: [0072] The topsheet may be
nested into the acquisition layer or vice versa such that the
three-dimensional protrusions of the topsheet and of the
acquisition layer coincide with and fit together, as shown in FIGS.
15A, 15B and 16A. [0073] Alternatively or in addition to what has
been set out above, one of the topsheet or acquisition layer may be
interrupted in the area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate such that the three-dimensional
protrusions made of the respective other non-interrupted topsheet
or acquisition layer interpenetrate the interruptions of the
topsheet or of the acquisition layer, as shown in FIGS. 15C and
16B. [0074] Alternatively or in addition to what has been set out
above, one of the topsheet or acquisition layer may be interrupted
in the area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate such that the three-dimensional
protrusions made of the respective other non-interrupted topsheet
or acquisition layer at least partially fit together with the
three-dimensional protrusions of the interrupted topsheet or of the
interrupted acquisition layer, as shown in FIGS. 15D, 15E, 16C and
16D. [0075] Alternatively or in addition to what has been set out
above, the topsheet and acquisition layer may be interrupted in the
area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate and the three-dimensional
protrusions of the topsheet coincide with and fit together with the
three-dimensional protrusions of the acquisition layer. The
interruptions in the topsheet in the area of the three-dimensional
protrusions of the topsheet/acquisition layer laminate will not
coincide with the interruptions in the acquisition layer in the
area of the three-dimensional protrusions of the
topsheet/acquisition layer laminate, as shown in FIGS. 15F and
16E.
[0076] The term "cellulosic fiber" as used herein refers to natural
fibers which typically are wood pulp fibers. Applicable wood pulps
include chemical pulps, such as Kraft, sulfite, and sulfate pulps,
as well as mechanical pulps including, for example, groundwood,
thermomechanical pulp and chemically modified thermomechanical
pulp. Pulps derived from both deciduous trees (hereinafter, also
referred to as "hardwood") and coniferous trees (hereinafter, also
referred to as "softwood") may be utilized. The hardwood and
softwood fibers can be blended, or alternatively, can be deposited
in layers to provide a stratified web.
[0077] The term "dry-laid fiber" as used herein means fibers which
have been provided in a fluid medium which is gaseous (air).
[0078] The term "wet-laid fiber" as used herein comprises
cellulosic fibers which have been suspended in an aqueous medium,
such as water, before being converted into a web and dried
according to a wet-laid papermaking process.
[0079] The term "web" as used herein means a material capable of
being wound into a roll. Webs may be nonwovens.
[0080] The term "nonwoven web" as used herein refers to a
manufactured material, web, sheet or batt of directionally or
randomly oriented fibers, bonded by friction, and/or cohesion
and/or adhesion, excluding paper and products which are woven,
knitted, tufted, stitch-bonded, incorporating binding yarns or
filaments, or felted by wet milling, whether or not additionally
needled. The fibers may be of natural or man-made origin. The
fibers may be staple or continuous filaments or be formed in situ.
The porous, fibrous structure of a nonwoven may be configured to be
liquid permeable or impermeable, as desired.
[0081] The term "absorbent core" as used herein refers to a
component, which is placed or is intended to be placed within an
absorbent article and which comprises an absorbent material
enclosed in a core wrap. The term "absorbent core" does not include
an acquisition or distribution layer or any other component of an
absorbent article which is not either an integral part of the core
wrap or placed within the core wrap. The absorbent core is
typically the component of an absorbent article which comprises
all, or at least the majority of, superabsorbent polymer and has
the highest absorbent capacity of all the components of the
absorbent article.
[0082] The term "substantially free of absorbent material" or
"substantially absorbent material free" as used herein means that
the basis weight of the absorbent material in the substantially
absorbent material free areas is at least less than 10%, in
particular less than 5%, or less than 2%, of the basis weight of
the absorbent material in the rest of the absorbent core.
[0083] The term "superabsorbent polymers" (herein abbreviated as
"SAP") as used herein refer to absorbent materials which are
cross-linked polymeric materials that can absorb at least 10 times
their weight of an aqueous 0.9% saline solution as measured using
the Centrifuge Retention Capacity (CRC) test (EDANA method WSP
241.2-05E). The SAP of the invention may in particular have a CRC
value of more than 20 g/g, or more than 25 g/g, or from 20 to 50
g/g, or from 20 to 40 g/g, or 25 to 35 g/g. The SAP useful in the
invention includes a variety of water-insoluble, but
water-swellable polymers capable of absorbing large quantities of
liquid bodily exudates.
[0084] The term "joined to" as used herein encompasses
configurations in which an element is directly secured to another
element by affixing the element directly to the other element; and
configurations in which the element is indirectly secured to the
other element by affixing the element to intermediate member(s)
which in turn are affixed to the other element. The term "joined
to" encompasses configurations in which an element is secured to
another element at selected locations, as well as configurations in
which an element is completely secured to another element across
the entire surface of one of the elements. The term "joined to"
includes any known manner in which elements can be secured
including, but not limited to mechanical entanglement.
[0085] The term "joined adjacent to the transversal edges" as used
herein means that when a first and/or second transversal edge of a
first layer is/are joined adjacent to a first and/or second
transversal edges of a second layer, the first and/or second
transversal edge of the first layer are disposed within an area
spaced inboard from the first and/or second transversal edge of the
second layer. The area has a width which is from 1 to 30% of the
width of the second layer.
[0086] "Comprise," "comprising," and "comprises" are open ended
terms, each specifies the presence of the feature that follows,
e.g. a component, but does not preclude the presence of other
features, e.g. elements, steps, components known in the art or
disclosed herein. These terms based on the verb "comprise" should
be read as encompassing the narrower terms "consisting essential
of" which excludes any element, step or ingredient not mentioned
which materially affect the way the feature performs its function,
and the term "consisting of" which excludes any element, step, or
ingredient not specified. Any preferred or exemplary embodiments
described below are not limiting the scope of the claims, unless
specifically indicated to do so. The words "typically", "normally",
"advantageously" and the likes also qualify features which are not
intended to limit the scope of the claims unless specifically
indicated to do so.
[0087] Known three-dimensional topsheets are often obtained with
increased basis weight and fluffiness of the topsheet. However,
such relatively high basis weight and fluffiness (i.e. relatively
high void volume) for three-dimensional topsheets might lead to
increased wetness of the three-dimensional topsheets as more liquid
remains in the topsheet. Indeed, the three-dimensional topsheet
includes small pores which can be more difficult to be dewatered
through a secondary topsheet or an acquisition layer.
[0088] One solution could be the elimination of any secondary
topsheet or acquisition layer in order to put the three-dimensional
topsheet in direct contact with the absorbent core. However, this
may lead to an increase of the acquisition time and consequently an
increased risk of leakage. This risk may be tempered by adding a
relatively high amount of absorbent material in the absorbent core.
The solution of adding a relatively high amount of absorbent
material in the absorbent core, however, negatively impacts the
cost of the absorbent article and also leads to an increase in
overall absorbent article caliper.
[0089] It has been found that bringing the topsheet and acquisition
layer in a face to face relationship and having the
topsheet/acquisition layer laminate comprising three-dimensional
protrusions extending from a plane of the topsheet/acquisition
layer laminate can help maintaining or even improving the dryness
at the skin facing layer of the absorbent article, and also
maintaining the acquisition speed, as it will be more explained in
detail below. The three-dimensional protrusions are formed from the
fibers of the topsheet and the acquisition layer. A majority of the
three-dimensional protrusions each comprises a base forming an
opening having a protrusion base width, an opposed distal portion,
and one or more side walls between the bases and the distal
portions of the majority of the three-dimensional protrusions. The
base, distal portion and the one or more side walls are formed by
fibers such that the majority of the three-dimensional protrusions
has only an opening at the base.
General Description of the Absorbent Article 20
[0090] An exemplary absorbent article 20 in which the absorbent
core 28 of the invention can be used is a taped diaper 20 as
represented in FIG. 1; FIG. 4 and FIG. 5 with a different absorbent
core construction. FIG. 1; FIG. 4 and FIG. 5 are top plan views of
the exemplary diaper 20, in a flat-out state, with portions of the
structure being cut-away to more clearly show the construction of
the diaper 20. This diaper 20 is shown for illustration purpose
only as the invention may be used for making a wide variety of
diapers or other absorbent articles.
[0091] The absorbent article 20 comprises a topsheet/acquisition
layer laminate 245 formed from a liquid permeable topsheet 24 and
an acquisition layer 52. In other words, the absorbent article 20
comprises a liquid permeable topsheet 24 and an acquisition layer
52 characterized in that the topsheet 24 and acquisition layer 52
are joined to form a topsheet/acquisition layer laminate 245.
[0092] The absorbent article 20 comprises a liquid impermeable
backsheet 25 and an absorbent core 28 between the topsheet 24 and
the backsheet 25. The absorbent article 20 comprises a front edge
10, a back edge 12, and two longitudinal side edges 13. The front
edge 10 is the edge of the absorbent article 20 which is intended
to be placed towards the front of the user when worn, and the back
edge 12 is the opposite edge. The absorbent article 20 may be
notionally divided by a longitudinal axis 80 extending from the
front edge 10 to the back edge 12 of the absorbent article 20 and
dividing the absorbent article 20 in two substantially symmetrical
halves relative to this axis, when viewing the absorbent article 20
from the wearer facing side in a flat out configuration, as
exemplarily shown in FIG. 1, FIG. 4 and FIG. 5.
[0093] The absorbent article 20 may comprise a distribution layer
54 which may comprise a dry-laid fibrous structure or a wet-laid
fibrous structure. The topsheet/acquisition layer laminate 245 is
facing towards the body of the wearer when the absorbent article is
in use.
[0094] The wet-laid fibrous structure made of wet-laid fibers may
have a Wet burst Strength from 50 to 500 g according to the Wet
Burst Strength Test Method and combinations thereof.
[0095] The distribution layer 54 may comprise a dry-laid fibrous
structure. The dry-laid fibrous structure may comprise dry-laid
fibers 540. The dry-laid fibrous structure may comprise a mixture
including dry-laid fibers and superabsorbent polymers. The dry-laid
fibers may comprise intra-fiber cross-linked cellulosic fibers.
[0096] The distribution layer 54 may comprise a wet-laid fibrous
structure. The wet-laid fibrous structure may comprise wet-laid
fibers.
[0097] The distribution layer 54 may have an average basis weight
of from 30 to 400 gsm, in particular from 100 to 300 gsm or from 50
to 250 gsm.
[0098] As explained more in a process detailed below, the
topsheet/acquisition layer laminate 245 comprises the topsheet 24
and the acquisition layer 52 in a face to face relationship. The
topsheet/acquisition layer laminate 245 comprises three-dimensional
protrusions 250. For this, a topsheet 24 and an acquisition layer
52 can be simultaneously mechanically deformed and combined
together in a face to face relationship such that a
topsheet/acquisition layer laminate 245 is formed. The
topsheet/acquisition layer laminate 245 comprises mechanical
deformations forming three-dimensional protrusions 250 extending
from a plane of the topsheet/acquisition layer laminate 245. The
mechanical deformations provide a three-dimensional structure to
the topsheet/acquisition layer laminate 245.
[0099] The absorbent article 20 may comprise elasticized gasketing
cuffs 32 present between the topsheet 24 and the backsheet 25 and
upstanding barrier leg cuffs 34. FIGS. 1, 4 and 5 also show other
typical diaper components such as a fastening system comprising
fastening tabs 42 attached towards the back edge 12 of the
absorbent article 20 and cooperating with a landing zone 44 towards
the front edge 10 of the absorbent article 20. The absorbent
article 20 may also comprise other typical components, which are
not represented in the Figures, such as a back elastic waist
feature, a front elastic waist feature, transverse barrier cuff(s),
a lotion application, etc.
[0100] As shown in FIG. 7, the barrier leg cuffs 34 may be
delimited by a proximal edge 64 joined to the rest of the article
20, typically the topsheet 24 and/or the backsheet 25, and a free
terminal edge intended to contact and form a seal with the wearer's
skin. The barrier leg cuffs 34 may be joined at the proximal edge
64 by a bond 65 which may be made for example by adhesive bonding,
fusion bonding or combination of known bonding means. Each barrier
leg cuff 34 may comprise one, two or more elastic strings 35 to
provide a better seal. The gasketing cuffs 32 may be placed
laterally outwardly relative to the barrier leg cuffs 34. The
gasketing cuffs 32 can provide a better seal around the thighs of
the wearer. Usually each gasketing leg cuff 32 will comprise one or
more elastic string or elastic element 33 for example between the
topsheet 24 and the backsheet 25 in the area of leg openings.
[0101] The absorbent article 20 can also be notionally divided by a
transversal axis 90 in a front region and a back region of equal
length measured on the longitudinal axis, when the absorbent
article 20 is in a flat state. The absorbent article's transversal
axis 90 is perpendicular to the longitudinal axis 80 and placed at
half the length of the absorbent article 20. The length of the
absorbent article 20 can be measured along the longitudinal axis 80
from the front edge 10 to the back edge 12 of the absorbent article
20. The topsheet 24, acquisition layer 52, distribution layer 54
and absorbent core 28 each have a width which can be measured from
their respective transversal edges and in parallel to the
transversal axis 90. The absorbent article may also comprise front
ears 46 and back ears 40 as it is known in the art.
[0102] The absorbent article 20 is notionally divided in a front
region 36, a back region 38 and a crotch region 37 located between
the front and the back region of the absorbent article 20. Each of
the front, back and crotch region is 1/3 of the length of the
absorbent article 20.
[0103] The absorbent core 28 of the present invention may comprise
as absorbent material 60 a blend of cellulosic fibers (so called
"airfelt") and superabsorbent polymers in particulate form
encapsulated in one or more substrates, see for example U.S. Pat.
No. 5,151,092 (Buell). Alternatively, the absorbent core 28 may be
airfelt free as described in detail below.
[0104] Generally, the absorbent core 28 can be defined by the
periphery of the layer formed by the absorbent material 60 within
the core wrap 160, as seen from the top side of the absorbent core
28. The absorbent core 28 can take various shapes, in particular
display a so-called "dog bone" or "hour-glass" shape, which shows a
tapering along its width towards the middle or "crotch" region of
the core. In this way, the absorbent core 28 may have a relatively
narrow width in an area of the absorbent core 28 intended to be
placed in the crotch region of the absorbent article. This may
provide for example better wearing comfort. The absorbent core 28
may thus have a width (as measured in the transversal direction) at
its narrowest point which is less than about 100 mm, 90 mm, 80 mm,
70 mm, 60 mm or even less than about 50 mm. The absorbent core 28
can also be generally rectangular, see for example as shown in FIG.
5, but other deposition areas can also be used such as a "T" or "Y"
or "hour-glass" or "dog-bone" shape (See for example FIG. 4).
[0105] Some components of the absorbent article 20 will now be
discussed in more details.
"Airfelt-Free" Absorbent Core 28
[0106] The absorbent core 28 of the invention may comprise an
absorbent material 60 enclosed within a core wrap 160. The
absorbent material 60 may comprise from 80% to 100% of SAP, such as
SAP particles, by total weight of the absorbent material 60. The
core wrap 160 is not considered as an absorbent material 60 for the
purpose of assessing the percentage of SAP in the absorbent core
28.
[0107] By "absorbent material" it is meant a material which has at
least some absorbency and/or liquid retaining properties, such as
SAP, cellulosic fibers as well as some hydrophilically treated
synthetic fibers. Typically, adhesives used in making absorbent
cores have no absorbency properties and are not considered as
absorbent material. The SAP content may be substantially higher
than 80%, for example at least 85%, at least 90%, at least 95% and
even up to and including 100% of the weight of the absorbent
material 60 contained within the core wrap 160. This above SAP
content substantially higher than 80% SAP may provide a relatively
thin absorbent core 28 compared to conventional absorbent cores
typically comprising between 40-60% SAP and 40-60% of cellulosic
fibers. The absorbent material 60 of the invention may in
particular comprise less than 10% weight percent, or less than 5%
weight percent, or even be substantially free of natural and/or
synthetic fibers. The absorbent material 60 may advantageously
comprise little or no cellulosic fibers, in particular the
absorbent core 28 may comprise less than 15%, 10%, or 5% (airfelt)
cellulosic fibers by weight of the absorbent core 28, or even be
substantially free of cellulose fibers. Such absorbent core 28 may
be relatively thin and thinner than conventional airfelt cores.
FIG. 1, FIG. 2 and FIG. 3 are illustrations of an absorbent article
20 comprising an "airfelt-free" absorbent core 28.
[0108] "Airfelt-free" absorbent cores 28 comprising relatively high
amount of SAP with various absorbent core designs have been
proposed in the past, see for example in U.S. Pat. No. 5,599,335
(Goldman), EP1447066A1 (Busam), WO95/11652 (Tanzer),
US2008/0312622A1 (Hundorf), and WO2012/052172 (Van Malderen).
[0109] The absorbent core 28 of the invention may comprise adhesive
for example to help immobilizing the SAP within the core wrap 160
and/or to ensure integrity of the core wrap, 160 in particular when
the core wrap 160 is made of one or more substrates. The core wrap
160 will typically extend over a larger area than strictly needed
for containing the absorbent material 60 within.
Core Wrap 160
[0110] The absorbent material 60 is encapsulated in one or more
substrates. The core wrap 160 comprises a top side 16 facing the
topsheet 24 and a bottom side 16' facing the backsheet 25. The core
wrap 160 may be made of a single substrate folded around the
absorbent material 60. The core wrap 160 may be made of two
substrates (one mainly providing the top side 16 and the other
mainly providing the bottom side 16') which are attached to
another, as exemplarily shown in FIG. 2. Typical configurations are
the so-called C-wrap and/or sandwich wrap. In a C-wrap, as
exemplarily shown in FIG. 6, the longitudinal and/or transversal
edges of one of the substrate are folded over the other substrate
to form flaps. These flaps are then bonded to the external surface
of the other substrate, typically by bonding with an adhesive. The
so called C-wrap construction can provide benefits such as improved
resistance to bursting in a wet loaded state compared to a sandwich
seal.
[0111] The core wrap 160 may be formed by any materials suitable
for receiving and containing the absorbent material 60. The core
wrap 160 may in particular be formed by a nonwoven web, such as a
carded nonwoven, spunbond nonwoven ("5") or meltblown nonwoven
("M"), and laminates of any of these. For example spunmelt
polypropylene nonwovens are suitable, in particular those having a
laminate web SMS, or SMMS, or SSMMS, structure, and having a basis
weight range of about 5 gsm to 15 gsm. Suitable materials are for
example disclosed in U.S. Pat. No. 7,744,576, US2011/0268932A1,
US2011/0319848A1 or US2011/0250413A1. Nonwoven materials provided
from synthetic fibers may be used, such as polyethylene (PE),
polyethylene terephthalate (PET) and in particular polypropylene
(PP).
"Airfelt-Free" Absorbent Core 28 Comprising Substantially Absorbent
Material Free Areas 26
[0112] The absorbent core 28 may comprise an absorbent material
deposition area 8 defined by the periphery of the layer formed by
the absorbent material 60 within the core wrap 160.
[0113] The absorbent core 28 may comprise one or more substantially
absorbent material free area(s) 26 which is/are substantially free
of absorbent material 60 and through which a portion of the top
side 16 of the core wrap 160 is attached by one or more core wrap
bond(s) 27 to a portion of the bottom side 16' of the core wrap
160, as shown in FIGS. 5 and 6. In particular, there can be no
absorbent material 60 in these areas. Minimal amount such as
contaminations with absorbent material 60 that may occur during the
making process are not considered as absorbent material 60. The one
or more substantially absorbent material free area(s) 26 is/are
advantageously confined by the absorbent material 60, which means
that the substantially absorbent material free area(s) 26 do(es)
not extend to any of the edge of the absorbent material deposition
area 8.
[0114] If the substantially absorbent material free area 26 extends
to any of the edges of the absorbent material deposition area 8,
each substantially absorbent material free area 26 may have areas
of absorbent material 60 on either side of each substantially
absorbent material free area 26.
[0115] The absorbent core 28 may comprise at least two
substantially absorbent material free areas 26 symmetrically
disposed on both sides of the longitudinal axis of the absorbent
core 28, as shown in FIG. 5.
[0116] The substantially absorbent material free area(s) 26 may be
straight and completely oriented longitudinally and parallel to the
longitudinal axis but also may be curved or have one or more curved
portions.
[0117] Furthermore, in order to reduce the risk of liquid bodily
exudate leakages, the substantially absorbent material free area(s)
26 advantageously do not extend up to any of the edges of the
absorbent material deposition area 8, and are therefore surrounded
by and fully encompassed within the absorbent material deposition
area 8 of the absorbent core 28. Typically, the smallest distance
between a substantially absorbent material free area 26 and the
closest edge of the absorbent material deposition area 8 is at
least 5 mm.
[0118] "Airfelt free" absorbent cores 28 comprising substantially
absorbent material free areas 26 have been proposed, see for
example in EP Patent Application No. 12196341.7.
[0119] One or more channel(s) 26' along the substantially absorbent
material free area(s) 26 in the absorbent core 28 may start forming
when the absorbent material 60 absorbs a liquid and starts
swelling. As the absorbent core 28 absorbs more liquid, the
depressions within the absorbent core 28 formed by the channel(s)
26' will become deeper and more apparent to the eye and the touch.
The formation of the channel(s) 26' may also serve to indicate that
the absorbent article 20 has been loaded with liquid bodily
exudates. The core wrap bond(s) 27 should remain substantially
intact at least during a first phase as the absorbent material 60
absorbs a moderate quantity of liquid bodily exudates.
[0120] As shown in FIG. 7, when the absorbent material swells, the
core wrap bonds 27 remain at least initially attached in the
substantially absorbent material free areas 26. The absorbent
material 60 swells in the rest of the absorbent core 28 when it
absorbs a liquid, so that the core wrap thus forms channels 26'
along the substantially absorbent material free areas 26 comprising
the core wrap bonds 27.
General Structure and Properties of the Topsheet/Acquisition Layer
Laminate 245
[0121] A topsheet/acquisition layer laminate 245 having a
three-dimensional structure is provided.
[0122] An absorbent article 20 comprises a longitudinal axis 80, a
transversal axis 90 perpendicular to the longitudinal axis 80, a
liquid permeable topsheet 24 having a first and second surface, a
liquid impermeable backsheet 25, and an absorbent core 28. The
absorbent core 28 is located between the topsheet 24 and backsheet
25. The absorbent core 28 comprises an absorbent material 60.
[0123] The absorbent article 20 comprises an acquisition layer 52
having a first and second surface. The first surface of the
topsheet 24 will be facing towards the body of the wearer when the
absorbent article 20 is in use.
[0124] The liquid permeable topsheet 24 and the acquisition layer
52 are aligned in a face to face relationship such that the second
surface of the topsheet 24 is in contact with the first surface of
the acquisition layer 52. The topsheet 24 and the acquisition layer
52 comprise fibers.
[0125] The absorbent article 20 comprises a topsheet/acquisition
layer laminate 245 which comprises the topsheet 24 and the
acquisition layer 52 in a face to face relationship. The
topsheet/acquisition layer laminate 245 comprises mechanical
deformations forming three-dimensional protrusions 250 extending
from a plane of the topsheet/acquisition layer laminate 245. The
topsheet 24 and acquisition layer 52 may be in an intimate contact
with each other.
[0126] According to a process detailed below, the topsheet 24 and
the acquisition layer 52 can be simultaneously mechanically
deformed and combined together in a face to face relationship such
to provide a topsheet/acquisition layer laminate 245. This means
that both topsheet 24 and acquisition layer 52 can be mechanically
deformed and combined together at the same time during the process.
The topsheet/acquisition layer laminate 245 has a first surface
comprising the second surface of the acquisition layer 52.
[0127] The three-dimensional protrusions 250 are formed from the
fibers of the topsheet 24 and the acquisition layer 52. A majority
of the three-dimensional protrusions 250 each comprises a base 256
forming an opening and having a protrusion base width, an opposed
distal portion 257, and one or more side walls 255 between the
bases 256 and the distal portions 257 of the majority of the
three-dimensional protrusions 250. The base 256, distal portion 257
and the one or more side walls 255 are formed by fibers such that
the majority of the three-dimensional protrusions 250 has only an
opening at the base 256, as shown in FIG. 15A. At least 50% or at
least 80% of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may only have openings at
the base 256. The majority of the three-dimensional protrusions may
be obtained by the mechanical process described in detail
below.
[0128] The majority of the three-dimensional protrusions 250 may be
more than 50% or more than 60% or more than 70% or more than 80% or
more than 90% or more than 95% or more than 98% of the
three-dimensional protrusions 250 in the topsheet/acquisition layer
laminate 245.
[0129] The topsheet/acquisition layer laminate 245 has a first
surface comprising the second surface of the acquisition layer 52.
A portion of the backsheet 25 is joined to a portion of the
topsheet of the topsheet/acquisition layer laminate 245 such that
the first surface of the topsheet/acquisition layer laminate 245 is
facing towards the backsheet 25.
[0130] The fibers may substantially or completely surround the one
or more side walls 255 of the majority of the three-dimensional
protrusions 250. This means that there are multiple fibers which
contribute to form a portion of the side walls 255 and distal
portion 257 of a three-dimensional protrusion 250. The phrase
"substantially surround" does not require that each individual
fiber be wrapped substantially or completely around the side walls
255 of the majority of the three-dimensional protrusions 250.
[0131] The absorbent article 20 may comprise gasketing cuffs 32.
The majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may at least be present in
the area where the topsheet 24 overlaps the acquisition layer 52 in
the topsheet/acquisition layer laminate 245. However, the majority
of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may be present in the
acquisition layer 52 and in the topsheet 24, in the area which
extends parallel to the transversal axis 90 of the absorbent
article 20. The majority of the three-dimensional protrusions 250
of the topsheet/acquisition layer laminate 245 may be present in
the area which extends parallel to the longitudinal axis 80 of the
absorbent article 20, but which does not extend beyond the area
where gasketing cuffs 32 is attached to the absorbent article 20,
in particular to the topsheet 24, as shown in FIG. 2 or 3. In that
case, the majority of the three-dimensional protrusions 250 which
are formed in the topsheet 24 of the topsheet/acquisition layer
laminate 245, are formed from the fibers of the topsheet 24.
[0132] Alternatively, the majority of the three-dimensional
protrusions 250 of the topsheet/acquisition layer laminate 245 may
be present in the area which extend extends parallel to the
transversal axis 90 of the absorbent article 20 such that the area
comprising the three-dimensional protrusions of the topsheet 24
overlaps the acquisition layer 52. The length of the area of the
majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may be from 5% to 60% or
from 10% to 40% wider than the length of the acquisition layer 52
of the topsheet/acquisition layer laminate 245. The majority of the
three-dimensional protrusions 250 of the topsheet/acquisition layer
laminate 245 may extend in the area which extends parallel to the
longitudinal axis 80 of the absorbent article 20 such that the area
comprising the majority of the three-dimensional protrusions 250 of
the topsheet/acquisition layer laminate 245 overlaps the
acquisition layer 52. The width of the area of the majority of the
three-dimensional protrusions 250 of the topsheet/acquisition layer
laminate 245 may be from 5% to 60% or from 10% to 40% wider than
the width of the acquisition layer 52 of the topsheet/acquisition
layer laminate 245. In that case, the majority of the
three-dimensional protrusions 250 which are formed in the topsheet
24 of the topsheet/acquisition layer laminate 245, are formed from
the fibers of the topsheet 24.
[0133] In still another alternative, the majority of the
three-dimensional protrusions 250 of the topsheet/acquisition layer
laminate 245 may only be present where the topsheet 24 overlaps the
acquisition layer 52 in the topsheet/acquisition layer laminate
245, as shown in FIG. 4.
[0134] The majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may have a measured
protrusion height of at least 0.5 mm according to the Protrusion
Height Test Method as described below.
[0135] The majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may have a measured
protrusion height from 0.5 mm to 5 mm or from 0.7 mm to 3 mm or
from 1.0 mm to 2.0 mm according to the Protrusion Height Test
Method as described below.
[0136] The majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may have a measured
protrusion base width of the three-dimensional protrusions 250 of
at least 0.5 mm according to the Protrusion Base Width Test Method
as described below.
[0137] The majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may have a measured
protrusion base width of the three-dimensional protrusions 250 from
0.5 mm to 10 mm or from 0.5 mm to 5 mm or from 0.5 mm to 3.0 mm or
from 1.0 mm to 2.5 mm or from 1.5 mm to 2.5 mm according to the
Protrusion Base Width Test Method as described below.
[0138] The majority of the three-dimensional protrusions 250 having
a shape with a specific height and width can provide an impression
of depth and can support the caregiver's perception that the
absorbent article 20 is well able to absorb the liquid bodily
exudates.
[0139] Maintenance or improvement of the dryness of the
topsheet/acquisition layer laminate 245 is evaluated by the amount
of liquid in topsheet which is determined by the Liquid in Topsheet
method. The liquid in topsheet is the retained liquid bodily
exudates in the topsheet 54 of the topsheet/acquisition layer
laminate 245 after the absorbent article 20 has acquired the liquid
bodily exudates after a first gush.
[0140] The topsheet/acquisition layer laminate 245 has a liquid in
topsheet value of less than 220 mg or less than 200 mg less than
180 mg or less than 160 mg or less than 120 mg or less than 80 mg
according to the liquid in topsheet method. The
topsheet/acquisition layer laminate may have a Topsheet load less
than 0.7 g/g, preferably less than 0.5 g/g according to the Liquid
in Topsheet method. The topsheet/acquisition layer laminate may
have a Topsheet load from 0.05 g/g to 0.7 g/g or from 0.15 g/g to
0.5 g/g according to the Liquid in Topsheet method. The
topsheet/acquisition layer laminate 245 can help obtaining the same
or even reduced liquid in topsheet compared to the same absorbent
article 20 comprising the same topsheet 24 overlaying the same
acquisition layer 52 without any mechanical deformations forming
three-dimensional protrusions 250.
[0141] The topsheet 24 and the acquisition layer 52 in the
topsheet/acquisition layer laminate 250 may be in an intimate
contact with each other when compared to a topsheet 24 placed on
top of an acquisition layer 52 in the same absorbent article 20. At
the same time, the topsheet/acquisition layer laminate 245 is in
close contact with the underlaying layer, i.e. the optional
distribution layer 54 or the absorbent core 28, which allows the
liquid bodily exudates to flow from the topsheet 24 through the
acquisition layer 52 to the absorbent core 28 efficiently.
[0142] In addition, the topsheet/acquisition layer laminate 245
comprises three-dimensional protrusions 250. As set out above, the
majority of the three-dimensional protrusions 245 may have a
certain minimum measured protrusion height and protrusion base
width. The majority of the three-dimensional protrusions 250
provide therefore void volume to acquire the liquid bodily
exudates. Hence, the liquid bodily exudates can be transmitted more
efficiently from the topsheet/acquisition layer laminate 245 to the
distribution layer 54, which improves the dryness of the topsheet
24 of the topsheet/acquisition layer laminate 245.
[0143] Maintenance or even improvement of the dryness of the
topsheet/acquisition layer laminate 245 may be also assessed by the
rewet measured according to the rewet method as disclosed herein.
Rewet can be due to the squeezing out the acquired and absorbed
liquid bodily exudates from layers underneath into and onto the
topsheet 24. The squeezing out can be caused by the pressure
applied on the absorbent article 20. In that case, the liquid
bodily exudates can pass back through the topsheet 24 from below
the topsheet 24.
[0144] Rewet can be due to the wetness which has been entrapped
within or on the topsheet/acquisition layer laminate 245, i.e. the
liquid which is not absorbed by underlying layers.
[0145] The topsheet/acquisition layer laminate 245 may have a rewet
value of less than 220 mg or less than 180 mg or less than 150 mg
or less than 120 mg or less than 100 mg according to the rewet
method.
[0146] Rewet can therefore remain the same or even be reduced at
the skin of the wearer when it is compared to the same absorbent
article 20 comprising the same topsheet 24 overlaying the same
acquisition layer 52 without any mechanical deformations forming
three-dimensional protrusions 250. The topsheet/acquisition layer
laminate 245 may also enable more efficient use of an absorbent
core. Overall, for the topsheet 24 of the topsheet/acquisition
layer laminate 245, the dryness can be maintained or even be
improved versus a three-dimensional topsheet 24 placed on top of a
flat acquisition layer 52 which is not in an overall intimate
contact with the three-dimensional topsheet 24 in a same absorbent
article 20.
[0147] The topsheet/acquisition layer laminate may have a rewet
reduced by from 5% to 20% or from 10% to 30% or from 5% to 50%
compared to the same absorbent article which comprises the same
topsheet 24 overlaying the same acquisition layer 52 without any
mechanical deformations forming three-dimensional protrusions. The
majority of the three-dimensional protrusions 250 may comprise void
areas 253 which do not contact the skin of the wearer. The
absorbent article 20 may be in less contact with the skin of the
wearer in comparison with a flat topsheet. The void areas 253 of
the topsheet/acquisition layer laminate 245 can help the air to
permeate between the skin of the wearer and the
topsheet/acquisition layer laminate 245. The void areas 253 of the
topsheet/acquisition layer laminate 245 can improve the
breathability of the topsheet/acquisition layer laminate 245.
[0148] In addition to improve dryness, the void areas 253 of the
topsheet/acquisition layer laminate 245 can also allow feces to be
absorbed and acquired within them. In that case, the present
invention is suitable to absorb feces of relatively low
viscosity.
[0149] The absorbent article 20 has a total acquisition time which
is less than 400 s or less than 300 s or less than 250 s or less
than 200 s or less than 150 s according to the Flat Acquisition
test method.
[0150] A width of the acquisition layer 52 in a direction parallel
to the transversal axis 90 is less than a width of the topsheet 24
in a direction parallel to the transversal axis 90 of the absorbent
article 20. If the width of both topsheet 24 and acquisition layer
52 were the same, wicking of the liquid bodily exudates underneath
the gasketing cuffs 32 might occur. Hence, the liquid bodily
exudates might not be properly absorbed by the absorbent core 28,
which may lead to leakage of the liquid bodily exudates out of the
absorbent article. If the width of the acquisition layer 52 in a
direction parallel to the transversal axis 90 is less that the
width of the topsheet 24 in a direction parallel to the transversal
axis 90, the acquisition layer 52 which may receive the liquid
bodily exudates from the topsheet 24 can directly transmit the
liquid bodily exudates to the distribution layer 54 in order to be
subsequently absorb by the absorbent core 28. Hence, the liquid
bodily exudates temporary stored in the acquisition layer 52 of the
topsheet/acquisition layer laminate 245 will not readily be drawn
towards and underneath the gasketing cuffs 32 by capillary forces.
Leakage can thus be reduced by having the width of the acquisition
layer 52 in a direction parallel to the transversal axis 90 less
that the width of the topsheet 24 in the topsheet/acquisition layer
laminate 245 in a direction parallel to the transversal axis
90.
[0151] The width of the acquisition layer 52 in a direction
parallel to the transversal axis 90 of the topsheet/acquisition
layer laminate 245 may not be more than 40% wider than the width of
the distribution layer 54 and/or more than 20% wider than the width
of the absorbent core 28 in a direction parallel to the transversal
axis 90. In that case, the liquid bodily exudates may not
accumulate at or adjacent to the transversal edges of the
acquisition layer. Wicking of the liquid bodily exudates underneath
the gasketing cuffs 32 is prevented. Indeed, when the acquisition
layer 52 of the topsheet/acquisition layer laminate 245 is no more
than 20% wider than the width of the absorbent core 28, the liquid
bodily exudates can readily be transported into the absorbent core
28, which can efficiently drain the fluid from the acquisition
layer 52 into the absorbent core 28. Wicking of the liquid bodily
exudates form the acquisition layer 52 underneath the gasketing
cuffs 32 is prevented.
[0152] A portion of the backsheet 25 may be joined to the topsheet
24 at or adjacent to the transversal edges of the first surface of
the topsheet/acquisition layer laminate 245 in the cross direction.
The transversal edges of the first surface of the
topsheet/acquisition layer laminate 245 do not comprise any
acquisition layer 52. When a portion of the backsheet 25 is joined
to a portion of the topsheet 24 of the topsheet/acquisition layer
laminate 245, the acquisition layer 52 is then enveloped between
the topsheet 24 and the backsheet 25.
[0153] The absorbent article 20 may comprise a distribution layer
54 comprising a dry-laid fibrous structure or a wet-laid fibrous
structure between the topsheet/acquisition layer laminate 245 and
the absorbent core 28, as shown in FIG. 1.
[0154] The distribution layer 54 may be free of tow fibers.
[0155] The distribution layer 54 may for example comprise at least
50% by weight of cross-linked cellulose fibers. The cross-linked
cellulosic fibers may be crimped, twisted, or curled, or a
combination thereof including crimped, twisted, and curled. This
type of material has been used in the past in disposable diapers as
part of an acquisition system, for example US 2008/0312622 A1
(Hundorf).
[0156] Exemplary chemically cross-linked cellulosic fibers suitable
for a distribution layer 54 are disclosed in U.S. Pat. No.
5,549,791; U.S. Pat. No. 5,137,537; WO95/34329 or US2007/118087.
Exemplary cross-linking agents may include polycarboxylic acids
such as citric acid and/or polyacrylic acids such as acrylic acid
and maleic acid copolymers.
[0157] The distribution layer may typically have an average basis
weight of from 30 to 400 g/m.sup.2, in particular from 100 to 300
g/m.sup.2. The density of the distribution layer may vary depending
on the compression of the article, but may be of between 0.03 to
0.15 g/cm.sup.3, in particular 0.08 to 0.10 g/cm.sup.3 measured at
0.30 psi (2.07 kPa).
[0158] The dry-laid fibrous structure may comprise dry-laid fibers
540. The dry-laid fibrous structure may comprise a mixture
including superabsorbent polymers (SAP) and dry-laid fibers. The
dry-laid fibers may comprise intra-fiber cross-linked cellulosic
fibers.
[0159] The wet-laid fibrous structure may comprise wet-laid fibers.
The wet-laid fibrous structure may exhibit a Wet Burst Strength
from 50 to 500 g according to the Wet Burst Strength Test
Method.
[0160] The absorbent material 60 of the absorbent core 28 may
comprise from 80% to 100% of SAP, such as SAP particles, by total
weight of the absorbent material 60.
[0161] Another type of absorbent material may be water-absorbing
foams based on cross-linked monomers comprising acid groups, see
for example from EP 0 858 478 B1, WO 97/31971 A1, WO 99/44648 A1
and WO 00/52087 A1.
[0162] The acquisition layer 52 can receive the liquid bodily
exudates that pass through the topsheet 24 and can distribute them
to underlying absorbent layers. In such a case, the topsheet 24 in
the topsheet/acquisition layer laminate 245 may be less hydrophilic
than the acquisition layer 52. The topsheet 24 of the
topsheet/acquisition layer laminate 245 can be readily
dewatered.
[0163] In order to enhance dewatering of the topsheet 24 of the
topsheet/acquisition layer laminate 245, the pore size of the
acquisition layer 52 may be reduced. For this, the acquisition
layer 52 may made of fibers with relatively small denier. The
acquisition layer 52 may also have an increased density.
[0164] A carrier layer 17 may be disposed between the
topsheet/acquisition layer laminate 245 and the dry-laid fibrous
structure, as shown in FIG. 8, 9A. According to the method used for
making the three-dimensional structure of the topsheet/acquisition
layer laminate 245, when the topsheet 24 and acquisition layer 52
are mechanically deformed together, holes might unintentionally
occur. When the distribution layer 54 comprises a dry-laid fibrous
structure, the fibers 540 of the dry-laid fibrous structure may
pass through the unintentional holes formed at the
topsheet/acquisition layer laminate 245 and contact undesirably the
skin of the wearer. The carrier layer 17 may act as a barrier layer
to impede the fibers 540 of dry-laid fibrous structure from passing
through the holes of the topsheet/acquisition layer laminate 245
unintentionally formed by the three-dimensional mechanical
deformation of the topsheet 24 with the acquisition layer 52, as
shown in FIGS. 8 and 9A. Also, the carrier layer 17 may help the
transfer of the liquid bodily exudates from the
topsheet/acquisition layer laminate 245 to the dry-laid fibrous
structure.
[0165] The carrier layer 17 may comprise a first and second surface
(171, 172). The second surface 172 of the carrier layer 17 may be
facing the topsheet/acquisition layer laminate 245. The first
surface 171 of the carrier layer 17 may be attached at or adjacent
to its longitudinal edges to the absorbent core 28. Hence, when the
carrier layer 17 is disposed between the topsheet/acquisition layer
laminate 245 and the dry-laid fibrous structure, and the carrier
layer 17 is attached to the absorbent core 28, the fibers 540 of
the dry-laid fibrous structure may be not able to escape between
the carrier layer 17 and the absorbent core 28, as exemplified in
FIG. 9B. The attachment of the carrier layer 17 to the longitudinal
edges of the absorbent core 28 may include a uniform continuous
layer of adhesive 173, a discontinuous patterned application of
adhesive or an array of separate lines, spirals, or spots of
adhesive or be carried out via other means, e.g. ultrasonic
bonding, heat and pressure bonding.
[0166] Alternatively, the carrier layer 17 may be disposed between
the dry-laid fibrous structure and the absorbent core 28, as shown
in FIG. 10. Hence, the carrier layer may help to distribute and
transfer of the liquid bodily exudates from the distribution layer
54 to the absorbent core 28, as shown in FIGS. 10 and 11, which
enables more efficient use of the absorbent core 28.
[0167] The carrier layer 17 may be attached at or adjacent to its
longitudinal edges to the first surface of the topsheet/acquisition
layer laminate 245. Hence, when the carrier layer 17 is disposed
between the dry-laid fibrous structure and the absorbent core 28,
and the carrier layer 17 is attached to the first surface of the
topsheet/acquisition layer laminate 245, the fibers 540 of the
dry-laid fibrous structure may be not able to escape between the
topsheet/acquisition layer laminate 245 and the carrier layer 17.
The attachment of the carrier layer 17 to the longitudinal edges to
the first surface of the topsheet/acquisition layer laminate 245
may include a uniform continuous layer of adhesive, a discontinuous
patterned application of adhesive or an array of separate lines,
spirals, or spots of adhesive.
[0168] A length of the acquisition layer 52 of the
topsheet/acquisition layer laminate 245 in a direction parallel to
the longitudinal axis 80 may be less than the length of the
topsheet 24 in a direction parallel to the longitudinal axis 80 of
the absorbent article 20, as shown in FIG. 4. When the length of
the acquisition layer 52 of the topsheet/acquisition layer laminate
245 in a direction parallel to the longitudinal axis 80 is less
than the length of the topsheet 24 in a direction parallel to the
longitudinal axis 80, the liquid bodily exudates cannot be readily
drawn towards the longitudinal edges (10, 12) of the absorbent
article 20, which reduces leakage.
[0169] The length of the acquisition layer 52 in the
topsheet/acquisition layer laminate 245 may be less than the length
of the absorbent core 28 taken along the longitudinal axis 80 of
the absorbent article 20, see for example FIG. 4.
[0170] The acquisition layer 52 of the topsheet/acquisition layer
laminate 245 may be positioned in the front region 36 and at least
partially in the crotch region 37 of the absorbent article 20, as
shown in FIG. 12. In that case, positioning the acquisition layer
52 of the topsheet/acquisition layer laminate 245 in the front
region 36 of the absorbent article 20 helps for acquiring and
distributing the liquid bodily exudates such as urine, around the
pee point of the wearer.
[0171] The acquisition layer 52 of the topsheet/acquisition layer
laminate 245 may be positioned in the back region 38 and at least
partially in the crotch region 37 of the absorbent article 20, as
shown in FIG. 13. Positioning the acquisition layer 52 of the
topsheet/acquisition layer laminate 245 in the back region 38 of
the absorbent article 20 helps at acquiring the feces of the
wearer, especially when the feces have a low viscosity.
[0172] The majority of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 may protrude towards the
backsheet 25 or towards the body of the wearer when the absorbent
article is in use.
[0173] The topsheet/acquisition layer laminate 245 may be
notionally divided into a first and second area. The first area may
comprise three-dimensional protrusions 250 which protrude towards
the backsheet 25. The second area may comprise three-dimensional
protrusions 250 which protrude towards the body of the wearer when
the absorbent article is in use.
[0174] For instance, the first area may be located in the front
region 36 and at least partially in the crotch region 37 of the
absorbent article 20 and the second regions may be located in the
back region 38 and at least partially in the crotch region 37 of
the absorbent article 20.
[0175] Having the first area where the three-dimensional
protrusions 250 of the topsheet/acquisition layer laminate 245
protrude towards the backsheet 25 can help acquiring and absorbing
the liquid bodily exudates to the absorbent core 28. Having the
second area where the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 protrude towards the body
of the wearer when the absorbent article is in use can improve
cleaning the body from the exudates. Hence, a combination of the
first and second area can allow the absorbent article 20 to better
perform.
[0176] The topsheet 24 of the topsheet/acquisition layer laminate
245 may be coated with a lotion composition. The lotion composition
may be located in the areas of the topsheet 24 which are between
the three-dimensional protrusions 250 of the topsheet/acquisition
layer laminate 245.
[0177] Typical lotion compositions used in diapers are disclosed in
U.S. Pat. No. 6,426,444 B2. The resulting lotion composition may be
applied to the topsheet/acquisition layer laminate by spraying,
printing (e.g., flexographic printing), coating (e.g., contact slot
coating, gravure coating), extrusion, microencapsulation or
combinations of these application techniques.
[0178] The majority of the three-dimensional protrusions 250 may be
disposed in any suitable arrangement across the plane of the
topsheet/acquisition layer laminate 245. Suitable arrangements
include, but are not limited to: staggered arrangements, and zones.
In some cases, the topsheet/acquisition layer laminate 245 may
comprise both three-dimensional protrusions 250 and other features
known in the art such as embossments and apertures. The
three-dimensional protrusions 250 and other features may be in
separate zones, be intermixed, or overlap. Intermixed arrangements
can be created in any suitable manner. In some cases, intermixed
arrangements can be created by using the techniques described in
U.S. Patent Publication No. US 2012/0064298 A1, Orr, et al. In
other cases, overlapping arrangements can be created by forming the
three-dimensional protrusions 250 and then subsequently passing the
topsheet/acquisition layer laminate 245 between a forming member
having male forming elements thereon and a compliant surface, and
applying pressure to the web with the forming member and compliant
surface. These techniques for producing overlapping arrangements
enable three-dimensional protrusions 250 and other features to be
combined so they are disposed in different locations on the
topsheet/acquisition layer laminate 245 or they can cause at least
some of the three-dimensional protrusions 250 and at least some of
the other features (apertures, embossments) to be disposed in the
same location on the topsheet/acquisition layer laminate 245.
The Mechanical Deformations and the Resulted Three-Dimensional
Protrusions
[0179] The topsheet 24 and the acquisition layer 52 may be engaged
together between a first and second forming members (211, 212) and
be simultaneously mechanically deformed and combined together to
form the topsheet/acquisition layer laminate 245, as exemplified in
FIGS. 14A, 14B and 14C. The topsheet/acquisition layer laminate 245
comprises thus deformations forming three-dimensional protrusions
250.
[0180] The first and second forming member (211, 212) may be
drum-shaped, generally cylindrical as shown in FIGS. 14A, 14B and
14C, or plate-shaped.
[0181] The first forming member 211 of the apparatus 200 may have a
surface comprising a plurality of discrete, spaced apart male
forming elements 213 having a base that is joined to the first
forming member 211, a top that is spaced away from the base, and
sides that extend between the base and the top of the male forming
elements 213. The male forming elements 213 may have a plan view
periphery, and a height.
[0182] The top on the male forming elements 213 may have a rounded
diamond shape, see for example FIG. 14B, with vertical sidewalls
and a radiused or rounded edge at the transition between the top
and the sidewalls of the male forming element 213.
[0183] The second forming member 212 may have a surface comprising
a plurality of recesses 214 in the second forming member 212. The
recesses 214 may be aligned and configured to receive the
respective male forming elements 213 therein. Hence, each recess
214 of the second forming member 212 may be sufficiently large to
be able to receive each respective male forming element 213 of the
first forming member 211. The recesses 214 may have a similar shape
as the male forming elements 213. The depth of the recesses 214 may
be greater than the height of the male forming elements 213.
[0184] The first and second forming member (211, 212) may be
further defined by a depth of engagement (DOE) which is a measure
of the level of intermeshing of the first and second forming member
(211, 212), as shown in FIG. 14C. The depth of engagement (DOE) may
be measured from the tip of the male forming elements 213 to the
outermost portion of the surface of the second forming member 212
which portions are not within a recess 214. The depth of engagement
(DOE) may range from 1.5 mm to 5.0 mm or from 2.5 mm to 5.0 mm or
from 3.0 mm to 4.0 mm.
[0185] The first and second forming member (211, 212) may be
defined by a clearance between the first and second forming member
(211, 212) as shown in FIG. 14C. The clearance is the distance
between the side wall of the male forming element 213 and the side
wall of the recess 214. The clearance may range from 0.1 mm to 2 mm
or from 0.1 mm to 1.5 mm from 0.1 mm to 1 mm.
[0186] The topsheet 24 and the acquisition layer 52 may be
therefore engaged together between the first and second forming
members (211, 212) and be mechanically deformed and combined
together to form the topsheet/acquisition layer laminate 245. The
topsheet/acquisition layer laminate 245 comprises mechanical
deformations forming three-dimensional protrusions 250.
[0187] The present method, however, differs from some embossing
processes in which the top of the male elements compress the
material to be embossed against the bottom of the female elements,
thereby increasing the density of the region in which the material
is compressed.
[0188] The topsheet/acquisition layer laminate 245 may be
notionally divided into a first and second area. The first and/or
second area of the topsheet/acquisition layer laminate 245 may
comprise the majority of the three-dimensional protrusions 250
having different shapes.
[0189] Viewed from a cross-sectional view, i.e. in a Z-direction,
the majority of the three-dimensional protrusions 250 may have any
suitable shapes which include, but are not limited to:
bulbous-shaped, conical-shaped and mushroom shaped.
[0190] Viewed from above, the majority of the three-dimensional
protrusions 250 may have any suitable shapes which include, but are
not limited to: circular, diamond-shaped, round diamond-shaped,
U.S. football-shaped, oval-shaped, clover-shaped,
triangular-shaped, tear-drop shaped and elliptical-shaped
protrusions. The majority of the three-dimensional protrusions 250
may be non-circular.
[0191] The majority of the three-dimensional protrusions 250 may
form, in conjunction, one or more graphics. Having graphics can
support the caregiver's perception that the absorbent article is
well able to absorb the liquid bodily exudates.
[0192] Also, the majority of the three-dimensional protrusions 250
may form, in conjunction, one or more graphics such as a logo, e.g.
the Pampers Heart logo.
[0193] The majority of the three-dimensional protrusions 250 may
have similar plan view dimensions in all directions, or the
majority of the three-dimensional protrusions 250 may be longer in
one dimension than another. The majority of the three-dimensional
protrusions 250 may have different length and width dimensions. The
majority of the three-dimensional protrusions 250 may, thus, have a
ratio of length to width. The ratio of length to width can range
from 10:1 to 1:10.
[0194] The topsheet/acquisition layer laminate 245 may comprise a
plurality of three-dimensional protrusions 250 which extend towards
the distribution layer 54 (see also FIG. 2) or towards the carrier
layer 17 (see FIGS. 11, 12). When the majority of the
three-dimensional protrusions 250 extend towards the distribution
layer 54, the area of contact between the acquisition layer 52 of
the topsheet/acquisition layer laminate 245 and the underneath
distribution layer 54 is improved. The distribution layer 54 will
follow the shape of the majority of the three-dimensional
protrusions 250. Hence, the transfer of the liquid bodily exudates
from the topsheet/acquisition layer laminate 245 to the
distribution layer 54 can be increased.
[0195] FIG. 15A-FIG. 15F shows different alternatives of
three-dimensional protrusions 250. A bulbous-shaped protrusion may
be one type of three-dimensional protrusions 250 which may be
obtained by the process described above using the apparatus 200.
The topsheet/acquisition layer laminate 245 may comprise the
majority of the three-dimensional protrusions 250 extending towards
the backsheet 25.
[0196] As shown in FIG. 15A, the three-dimensional protrusion 250
is formed from the fibers of the topsheet 24 and the acquisition
layer 52. The majority of the three-dimensional protrusions 250 is
defined by a base 256 forming an opening, an opposed enlarged
distal portion 257 that extends to a distal end 259 and one or more
side walls 255 between the base 256 and the distal portion 257. The
base 256, distal portion 257 and one or more side walls 255 are
formed by fibers such that the majority of the three-dimensional
protrusions 250 has only an opening at the base 256, as shown in
FIG. 15A. The side wall 255 may be substantially continuous. For
instance, the side wall 255 may be spherical or conical. The
majority of the three-dimensional protrusions 250 may comprise more
than one side wall 255, e.g. in a pyramidal-shaped protrusion. The
fibers may substantially or completely surround the one or more
side walls 255 of the majority of the three-dimensional protrusions
250.
[0197] As shown in FIG. 15B, a three-dimensional protrusion 250
comprising an inner and outer three-dimensional protrusion 251A and
251B may be made from engaging the topsheet 24 with the acquisition
layer 52 between the first and second forming member (211, 212)
such as the inner three-dimensional protrusion 251A from the
topsheet 24 and the outer three-dimensional protrusion 251B from
the acquisition layer 52 coincide with and fit together. Hence, as
shown in FIG. 15B, the inner three-dimensional protrusion 251A of
the topsheet 24 and the outer three-dimensional protrusion 251B of
the acquisition layer 52 are nested together.
[0198] The inner three-dimensional protrusion 251A may comprise a
plurality of fibers 254A which constitutes the topsheet 24. The
outer three-dimensional protrusion 251B in which the inner
three-dimensional protrusion 251A may be nested, may comprise a
plurality of fibers 254B which constitutes the acquisition layer
52. The plurality of fiber (254A, 254B) composing the
three-dimensional protrusion 250 may surround the side walls 255 of
the three-dimensional protrusions 250.
[0199] The topsheet 24 and the acquisition layer 52 may be both
extensible, i.e. the fibers composing the topsheet 24 and
acquisition layer 52 may elongate and/or may mobile, such that the
topsheet 24 and acquisition layer 52 are able to stretch to be
nested together.
[0200] Generally, the extensibility of the materials composing the
topsheet 24 and acquisition layer 52 can be selected according to
the desired sizes of the three-dimensional protrusions 250. If
relatively large three-dimensional protrusions 250 are desired,
materials with a relatively higher extensibility will be
chosen.
[0201] For instance, the topsheet 24 or acquisition layer 52 may be
capable of undergoing an apparent elongation of equal to or greater
than at least 100% or 110% or 120% or 130% up to 200% in the
machine and/or cross-machine directions at or before reaching the
breaking force according to the Test Method as set out in the
Definition part.
[0202] In some cases, it might be desired to have the majority of
the three-dimensional protrusions 250 which are larger either in
the machine or cross-machine direction. For this, the materials
composing the topsheet 24 and acquisition layer 52 can be thus
relatively more extensible either along the longitudinal axis
versus the transversal axis of the absorbent article or vice
versa.
[0203] The majority of the three-dimensional protrusions 250 may
comprise a void area 253 which is the portion of the
three-dimensional protrusion 251A which does not comprise any
fibers or very little fibers. The majority of the three-dimensional
protrusions 250 may be defined by a protrusion base width WB.sub.1
of the base 256 forming an opening which is measured from two side
walls of the inner portion 251A at the base 256. The majority of
the three-dimensional protrusions 250 may be defined by a width
WD.sub.2 of the void area 253 which is the maximum interior width
measured between two side walls of the inner three-dimensional
protrusion 251A or which is the maximum diameter of the side wall
of the inner three-dimensional protrusion 251A when the distal
portion has a substantially circular shape. The maximum interior
width WD.sub.2 of the void area 253 at the distal portion may be
greater than the protrusion base width WB.sub.1 of the base 256 of
the three-dimensional protrusion 250. The protrusion base width
WB.sub.1 of the base 256 of the majority of the three-dimensional
protrusions 250 may range from 1.5 mm to 15 mm or from 1.5 mm to 10
mm or from 1.5 mm to 5 mm or from 1.5 mm to 3 mm. Measurements of
the dimensions of the protrusion base width WB.sub.1 of the base
256 and the width WD.sub.2 of the distal portion 257 can be made on
a photomicrograph. When the size of the protrusion base width
WB.sub.1 of the base 256 is specified herein, it will be
appreciated that if the openings are not of uniform width in a
particular direction, the protrusion base width, WB.sub.1, is
measured at the widest portion. Measurements of the protrusion base
width WB.sub.1 of the base 256 or the maximum interior width
WD.sub.2 of the void area 253 at the distal portion 257 can be made
on a photomicrograph at 20.times. magnification.
[0204] As the plurality of fiber (254A, 254B) composing the
majority of the three-dimensional protrusions 250 may be present in
the one or more side walls 255 of the majority of the
three-dimensional protrusions 250, the majority of the
three-dimensional protrusions 250 may not collapse on one side and
close off the opening at the base 256 when compressive forces are
applied on the topsheet/acquisition layer laminate 245. The opening
at the base 256 may be maintained and may create a ring of
increased opacity around the opening at the base 256 when the
three-dimensional protrusion 250 has been compressed. Hence, the
majority of the three-dimensional protrusions 250 can be preserved
and remain visible to the consumer when viewing the absorbent
article 20 from the topsheet 24. The majority of the
three-dimensional protrusions 250 can be preserved after being
subjected to any inherent compressive forces due to the process or
the step of compressing the absorbent articles comprising the
topsheet/acquisition layer laminate 245 prior to be filled in a
packaging.
[0205] In other words, the majority of the three-dimensional
protrusions 250 may have a degree of dimensional stability in the
X-Y plane when a Z-direction force is applied to the majority of
the three-dimensional protrusions 250. It is not necessary that the
collapsed configuration of the majority of the three-dimensional
protrusions 250 be symmetrical, only that the collapsed
configuration prevent the majority of the three-dimensional
protrusions 250 from flopping over or pushing back into the
original plane of the topsheet/acquisition layer laminate 245.
Without wishing to be bound to any particular theory, the wide base
256 and large cap 52 (greater than the protrusion base width of the
base opening 256), combined with the lack of a pivot point, causes
the three-dimensional protrusions 250 to collapse in a controlled
manner (the large distal portion 257 prevents the three-dimensional
protrusion 250 from flopping over and pushing back into the
original plane of the topsheet/acquisition layer laminate 245).
Thus, the majority of the three-dimensional protrusions 250 are
free of a hinge structure that would otherwise permit them to fold
to the side when compressed.
[0206] It may be desirable for at least one of the
three-dimensional protrusions 250 in the topsheet/acquisition layer
laminate 245 to collapse in a controlled manner described below
under the 7 kPa load when tested in accordance with the Accelerated
Compression Method in the Test Methods section below.
[0207] Alternatively, at least some, or in other cases, a majority
of the three-dimensional protrusions 250 may collapse in the
controlled manner described herein.
[0208] Alternatively, substantially all of the three-dimensional
protrusions 250 may collapse in the controlled manner described
herein. The ability of the three-dimensional protrusions 250 to
collapse may also be measured under a load of 35 kPa. The 7 kPa and
35 kPa loads simulate manufacturing and compression packaging
conditions. Wear conditions can range from 2 kPa or less up to 7
kPa.
[0209] Generally, the majority of the three-dimensional protrusions
250 may be configured to collapse in a controlled manner such that
each base 256 forming an opening remains open, and the protrusion
base width of each base 256 forming an opening is greater than 0.5
mm after compression.
[0210] In the area of the three-dimensional protrusions 250, the
topsheet 24 and/or acquisition layer 52 may comprise one or more
interruptions. The formation of the one or more interruptions may
be due to the properties of the topsheet 24 and acquisition layer
52. The topsheet 24 may less extensible with regard to fiber
mobility and/or fiber extensibility than the acquisition layer 52
or vice versa such that a hole starts to form in the topsheet 24
and/or acquisition layer 52.
[0211] As shown in FIG. 15C, the acquisition layer 52 may be
interrupted in the area of the three-dimensional protrusion 250 of
the topsheet/acquisition layer laminate 245.
[0212] Generally, the acquisition layer 52 may have a lower
extensibility than the topsheet 24. In such cases, the acquisition
layer 52 may start to rupture and form an interruption, i.e. the
fibers composing the acquisition layer 52 may be less extensible
and/or mobile than the fibers composing the topsheet 24.
[0213] The three-dimensional protrusion 251A made of the respective
other non-interrupted topsheet interpenetrates the interrupted
acquisition layer 52. In such case, the interruptions may be formed
by locally rupturing the acquisition layer 52 by the process
described in detail above. The interpenetration may be achieved by
pushing the topsheet 24 through the acquisition layer 52. In order
to obtain these three-dimensional protrusions, the depth of
engagement (DOE) of the apparatus 200 may be adequately selected
from 2 to 10 mm, or from 3 to 7 mm. The interrupted acquisition
layer 52 may have any suitable configuration in the area of the
three-dimensional protrusion 250. The rupture may involve a simple
splitting open of the acquisition layer 52 such that the
interruption in the acquisition layer 52 remains a simple
two-dimensional hole. It might happen that a portion of the
acquisition layer 52 in the area of the three-dimensional
protrusion 250 may be slightly deflected or urged out-of-place to
form flaps 269.
[0214] When the respective other non-interrupted topsheet 24
interpenetrates the interrupted acquisition layer 52, the topsheet
24 can be brought in direct contact with the underlying layer, e.g.
the carrier layer 17, the distribution layer 54 or the absorbent
core 28, leading to an efficient topsheet dewatering, which can
improve the dryness of the topsheet/acquisition layer laminate
245.
[0215] Alternatively, as shown in FIG. 15D or 15E, the acquisition
layer 52 may be interrupted in the area of the three-dimensional
protrusion 250 of the topsheet/acquisition layer laminate 245. The
three-dimensional protrusion 251B of the interrupted acquisition
layer 52 may comprise an interruption 258B. The three-dimensional
protrusion 251A of the non-interrupted topsheet 24 may coincide
with and fit together with the three-dimensional protrusion 251B of
the interrupted acquisition layer, as shown in FIG. 15D. In other
words, the topsheet 24 is not pushed through the acquisition layer
52 such that the topsheet 24 does not interpenetrate through the
acquisition layer 52.
[0216] Alternatively, the three-dimensional protrusion 251A of the
non-interrupted topsheet 24 may partially fit together with the
three-dimensional protrusion 251B of the interrupted acquisition
layer, as shown in FIG. 15E.
[0217] Likewise, the topsheet 24 may be interrupted in the area of
the three-dimensional protrusion 250 of the topsheet/acquisition
layer laminate 245.
[0218] Generally, the topsheet 24 may have a lower extensibility
than the acquisition layer 52. In such cases, the topsheet 24 may
start to rupture and form an interruption, i.e. the fibers
composing the topsheet 24 may be less extensible and/or mobile than
the fibers composing the acquisition layer 52.
[0219] In another alternative, the topsheet 24 and acquisition
layer 52 may be interrupted in the area of the three-dimensional
protrusions 250 of the topsheet/acquisition layer laminate 245 and
the three-dimensional protrusions of the topsheet 251A coincide
with and fit together with the three-dimensional protrusions 251B
of the acquisition layer. The interruptions 258A in the topsheet 24
in the area of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245 will not coincide with the
interruptions 258B in the acquisition layer 52 in the area of the
three-dimensional protrusions 250 of the topsheet/acquisition layer
laminate 245, as shown in FIG. 15F. In this case, the interruptions
(258A, 258B) in the topsheet 24 and acquisition layer 52 are in
different locations in the three-dimensional protrusions 250.
[0220] The majority of the three-dimensional protrusions 250 may
protrude towards the body of the wearer when the absorbent article
20 is in use (see also FIG. 3). When the majority of the
three-dimensional protrusions 250 protrude towards the body of the
wearer when the absorbent article 20 is in use, the area of contact
between the topsheet 24 of the topsheet/acquisition layer laminate
245 and the wearer's skin can be reduced in order to lead to an
enhanced dryness feeling and comfort. Hence, the
topsheet/acquisition layer laminate 245 provides cushioning to the
wearer and an improved sensation of comfort.
[0221] FIG. 16A-FIG. 16E shows alternatives how a plurality of
three-dimensional protrusions 250, e.g. bulbous-shaped protrusions,
may protrude from the acquisition layer 52 to the topsheet 24 of
the topsheet/acquisition layer laminate 245. In those alternatives,
a three-dimensional protrusion 250 may comprise an inner and outer
three-dimensional protrusion 251A and 251B. The inner
three-dimensional protrusion 251A of the acquisition layer 52 is
nested in the outer three-dimensional protrusion 251B of the
topsheet 24. The inner three-dimensional protrusion 251A may
comprise a plurality of looped fibers 254B of the acquisition layer
52. The outer three-dimensional protrusion 251B in which the inner
three-dimensional protrusion 251A is nested, may comprise a
plurality of looped fibers 254A of the topsheet 24.
[0222] An area of 10 cm.sup.2 of the topsheet/acquisition layer
laminate 245 may comprise from 5 to 100 three-dimensional
protrusions 250 from 10 to 50 three-dimensional protrusions 250 or
from 20 to 40 three-dimensional protrusions 250.
Fiber Concentration
[0223] The topsheet 24 may comprise a generally planar first region
of the topsheet 24. The acquisition layer 52 may comprise a
generally planar first region of the acquisition layer 52. The
three-dimensional protrusions of the respective topsheet 24 and the
acquisition layer 52 may comprise a plurality of discrete integral
second regions. The term "generally planar" is not meant to imply
any particular flatness, smoothness, or dimensionality. Thus, the
first region of the topsheet 24 can include other features that
provide the first region of the topsheet 24 with a topography. The
first region of the acquisition layer 52 can include other features
that provide the first region of the acquisition layer 52 with a
topography. Such other features can include, but are not limited to
small protrusions, raised network regions around the base 256
forming an opening, and other types of features. Thus, the first
region of the topsheet 24 and/or the first region of the
acquisition layer 52 can be generally planar when considered
relative to the respective second regions. The first region of the
topsheet 24 and/or the first region of the acquisition layer 52 can
have any suitable plan view configuration. In some cases, the first
region of the topsheet 24 and/or the first region of the
acquisition layer 52 can be in the form of a continuous
inter-connected network which comprises portions that surround each
of the three-dimensional protrusions 250.
[0224] The side walls 259 and the area around the base 256 of the
majority of the three-dimensional protrusions 250 may have a
visibly significantly lower concentration of fibers per given area
(which may be evidence of a lower basis weight or lower opacity)
than the portions of the topsheet 24 and/or the acquisition layer
52 in the unformed first region of the respective topsheet 24 and
the acquisition layer 52. The majority of the three-dimensional
protrusions 250 may also have thinned fibers in the side walls 259.
Thus, the fibers may have a first cross-sectional area when they
are in the undeformed topsheet 24 and the acquisition layer 52, and
a second cross-sectional area in the side walls 259 of the majority
of the three-dimensional protrusions 250 of the
topsheet/acquisition layer laminate 245, wherein the first
cross-sectional area is greater than the second cross-sectional
area. The side walls 259 may also comprise some broken fibers as
well. The side walls 259 may comprise greater than or equal to
about 30%, alternatively greater than or equal to about 50% broken
fibers.
[0225] As used herein, the term "fiber concentration" has a similar
meaning as basis weight, but fiber concentration refers to the
number of fibers/given area, rather than g/area as in basis
weight.
[0226] The topsheet/acquisition layer laminate 245 may comprise the
majority of the three-dimensional protrusions 250 which are
oriented with the base 256 facing upward in which the concentration
of fibers at the distal end 259 of each respective topsheet 24 and
the acquisition layer 52 differs between the topsheet 24 and the
acquisition layer 52.
[0227] The concentration of fibers in the first region of the
acquisition layer 52 and in the distal ends 259 of the majority of
the three dimensional protrusions 250 may be greater than the
concentration of fibers in the side walls 255 of the majority of
the three dimensional protrusions 250 in the acquisition layer
52
[0228] The concentration of fibers in the first region of the
topsheet 24 and in the distal ends 259 of the majority of the three
dimensional protrusions 250 may be greater than the concentration
of fibers in the side walls 255 of the majority of the three
dimensional protrusions 250 in the topsheet 24.
[0229] Alternatively, the concentration of fibers in the first
region of the acquisition layer 52 may be greater than the
concentration of fibers in the side walls 255 of the majority of
the three-dimensional protrusions 250 in the acquisition layer 52,
and the concentration of fibers in the side walls 255 of the
majority of the three-dimensional protrusions 250 in the
acquisition layer 52 may be greater than the concentration of
fibers forming the distal ends 259 of the majority of the
three-dimensional protrusions 250 in the acquisition layer 52.
[0230] The concentration of fibers in the first region of the
acquisition layer 52 may be greater than the concentration of
fibers in the distal ends 259 of the majority of the three
dimensional protrusions 250 in the acquisition layer 52, and the
concentration of fibers in the first region of the topsheet 24 and
the distal ends 259 of the majority of the three dimensional
protrusions 250 may be greater than the concentration of fibers in
the side walls 255 of the majority of the three dimensional
protrusions 250 in the topsheet 24.
[0231] A portion of the fibers that form the first region fibers in
the acquisition layer 52 and/or the topsheet 24 may comprise
thermal point bonds, and the portion of the fibers in the
acquisition layer 52 and/or the topsheet 24 forming the side walls
255 and distal ends 259 of the majority of the three-dimensional
protrusions 250 may be substantially free of thermal point bonds.
In at least some of the three-dimensional protrusions, at least
some of the fibers in the acquisition layer 52 and/or the topsheet
24 may form a nest or circle around the perimeter of the
three-dimensional protrusion 250 at the transition between the side
wall 255 and the base 256 of the three-dimensional protrusion
250.
[0232] In some cases, the topsheet 24 or the acquisition layer 52
may have a plurality of bonds (such as thermal point bonds) therein
to hold the fibers together. Any such bonds are typically present
in the precursor materials from which the respective topsheet 24 or
the acquisition layer 52 are formed.
[0233] Forming three-dimensional protrusions 250 in the
topsheet/acquisition layer laminate 245 may also affect the bonds
(thermal point bonds) within the topsheet 24 and/or the acquisition
layer 52.
[0234] The bonds within the distal end 259 of the three-dimensional
protrusions 250 may remain intact (not be disrupted) by the
mechanical deformation process that formed the three-dimensional
protrusions 250. In the side walls 255 of the three-dimensional
protrusions 250, however, the bonds originally present in the
precursor topsheet 24 and/or the acquisition layer 52 may be
disrupted. When it is said that the bonds may be disrupted, this
can take several forms. The bonds can be broken and leave remnants
of a bond. In other cases, such as where the precursor materials of
the respective topsheet 24 or the acquisition layer 52 is
underbonded, the fibers can disentangle from a lightly formed bond
site (similar to untying a bow), and the bond site will essentially
disappear. In some cases, after the mechanical deformation process,
the side walls 255 of the majority of the three-dimensional
protrusions 250 may be substantially free (or completely free) of
thermal point bonds.
[0235] The bonds within the first region of the topsheet 24 and the
distal end 259 of the three-dimensional protrusions 250 may remain
intact. In the side walls 255 of the three-dimensional protrusions
250, however, the bonds originally present in the precursor
topsheet 24 may be disrupted such that the side walls 255 are
substantially free of thermal point bonds. Such a topsheet 24 could
be combined with an acquisition layer 52 in which the concentration
of fibers within the topsheet 24 in the first region and the distal
end 259 of the three-dimensional protrusions 250 is also greater
than the concentration of fibers in the side walls 255 of the
three-dimensional protrusions 250.
[0236] The acquisition layer 52 may have thermal point bonds within
the first region of the acquisition layer 52 and the distal end 259
of the three-dimensional protrusions 250 that remain intact. In the
side walls 255 of the three-dimensional protrusions 250, however,
the bonds originally present in the precursor acquisition layer 52
comprising the acquisition layer 52 may be disrupted such that the
side walls 255 of the acquisition layer 52 are substantially free
of thermal point bonds. In other cases, the thermal point bonds in
the acquisition layer 52 at the distal end 259 of the
three-dimensional protrusions 250 may also be disrupted so that the
distal end 259 of at least some of the three-dimensional
protrusions 250 are substantially or completely free of thermal
point bonds.
Indicia
[0237] The topsheet 24, the acquisition layer 52, and/or the
carrier layer 17 may comprise one or more indicia. In other
instances, more than one of these layers may comprise an
indicia.
[0238] The term "indicia", as used herein, may comprise one or more
inks with pigments, adhesives with pigments, words, designs,
trademarks, graphics, patterns, and/or pigmented areas, for
example. The term "indicia" does not include a fully tinted or
colored layer. The indicia may typically be a different color than:
(1) the layer that it is printed on, positioned on, or applied to;
or (2) a different color than other layers of an absorbent article
20.
[0239] The phrase a "different color" means a different shade of
the same color (e.g., dark blue and light blue) or may be
completely different color (e.g., blue and gray).
[0240] The indicia should be at least partially visible from either
a wearer facing surface, a garment facing surface, or both of an
absorbent article 20, although the indicia may not be printed on,
positioned or, on applied to the wearer or garment facing surfaces
of the absorbent articles 20.
[0241] The indicia may be printed on, positioned on, or applied to
three-dimensional protrusions areas and non three-dimensional
protrusions areas, three-dimensional protrusion areas only, or non
three-dimensional protrusions areas only, for example. A
three-dimensional protrusion area may comprise a portion or all of
the majority of the three-dimensional protrusions 250.
[0242] The indicia may comprise a light activatable material, a
liquid activatable material, a pH activatable material, a
temperature activatable material, a menses activatable material, a
urine activatable material, or BM activatable material, or an
otherwise activatable material. These activatable materials may
typically undergo a chemical reaction, or other reaction, to change
the indicia from one color to a different color, from one color to
a different shade of the same color, from a color that is not
visually distinguishable in an absorbent article 20 to a color that
is visually distinguishable in an absorbent article 20, or from a
color that is visually distinguishable in an absorbent article 20
to a color that is not visually distinguishable in an absorbent
article 20.
[0243] In an instance, the indicia may grow or shrink or display a
graphic/not display a graphic after the indicia undergoes the
reaction. In other instances, the indicia may be activated by a
stress or a strain during manufacture or wear.
[0244] The indicia may be white or non-white. If the indicia is
white in color, at least one layer may be non-white so that the
indicia is visible from a wearer and/or garment facing surface of
the absorbent articles 20, for example.
[0245] The indicia may comprise embossments, fusion bonds, or other
mechanical deformations. In other instances the indicia may at
least partially overlap embossments, fusion bonds, or other
mechanical deformations.
[0246] In some instances, the indicia may be formed within either a
sheath or a core of bicomponent fibers. For example, a core may be
white, while a sheath may be blue, or vice versa.
[0247] The indicia may be on, positioned on, formed on, formed
with, printed on, or applied to all of, or part of, a certain
layer. The indicia may also be on, positioned on, formed on, formed
with, printed on, or applied to one or more layers, or on all
suitable layers of an absorbent article 20. The indicia may be on,
positioned on, formed on, formed with, printed on, or applied to
either side, or both sides, of the one or more layers of an
absorbent article 20. In some instances, suitable layers for
indicia placement comprise one or more of a topsheet 24, a
secondary topsheet, an acquisition layer 52, a distribution layer
54, a carrier layer 17, a core wrap 160, a bottom side 16' of the
core wrap 160, a top side 16 of the core wrap 160, and/or an
additional layer positioned at least partially intermediate the
topsheet 24 and the top side 16 of the core wrap 160 (hereafter
sometimes referred to as "materials suitable for indicia
placement").
[0248] Either in addition to or separate from the indicia described
above, any one or more of the suitable layers for indicia
placement, or a portion thereof, may have a color different than
any one or more of the remaining layers for indicia placement, or a
portion thereof. The definition of the phrase "different color"
above also applies to this part of the disclosure. In some
instances, the indicia may be a different color than any one or
more of the suitable layers for indicia placement.
[0249] Alternatively, an indicia may be on one of the suitable
layers for indicia placement while another one of the remaining
suitable layers for indicia placement may be a different color than
the indicia. One example may be a blue indicia on a white carrier
layer 17 with the acquisition layer 52 or topsheet 24 being
teal.
[0250] In another example, a blue indicia may be on a white carrier
layer 17 with the acquisition layer 52 and topsheet 24 also being
white. As such, the blue indicia may be viewable from a
wearer-facing surface.
[0251] In another example, a blue indicia may be on an acquisition
layer 52, wherein the topsheet 24 and the acquisition layer 52 are
simultaneously mechanically deformed and combined together,
preferably nested together to provide a topsheet/acquisition layer
laminate 245 having three-dimensional protrusions 250.
[0252] In an instance where the topsheet and the acquisition layer
are simultaneously mechanically deformed and combined together,
preferably nested together to provide a topsheet/acquisition layer
laminate 245 having three-dimensional protrusions 250, the indicia
may be applied to the acquisition layer 52 or the topsheet 24
before or after such mechanical deformation (or preferably namely
nesting).
[0253] In an example, two different indicia may be positioned on
the same or different layers for indicia placement. The two
different indicia may be different in color, pattern, and/or
graphic, for example. If the two different indicia are on different
layers for indicia placement, the two layers may be the same color
or different colors, or have portions that are the same color or
different colors.
[0254] In some instances, a visible color of a portion of, or all
of, the interior (wearer-facing surface) of an absorbent article 20
may be coordinated with and/or compliment a visible color of a
portion of, or all of, the exterior (garment-facing surface) of the
absorbent article 20, as described in further detail in U.S. Pat.
No. 8,936,584. The indicia visible from the interior may also be
coordinated with and/or compliment the indicia visible from the
exterior of the absorbent article 20. In such an instance, the
backsheet 25 of the absorbent article 20 may comprise an outer
cover nonwoven and a backsheet film. The indicia visible from the
exterior of the absorbent article 20 may be on the outer cover
nonwoven or the backsheet film.
[0255] In still other instances, the visible indicia and/or color
from the interior may also be coordinated with or compliment the
indicia and/or color visible from the exterior of the absorbent
article 20.
[0256] In addition to that described above, a first portion of one
of the suitable layers for indicia placement may be a first color
and a second portion of the same of the suitable layers for indicia
placement may be a second color. The first and second colors may be
a different color. In other instances, a first portion of one of
the suitable layers for indicia placement may be a first color and
a second portion of a different one of the suitable layers for
indicia placement may be a second color. The first and second
colors may be a different color.
[0257] In an instance, in an absorbent article 20, one of a
topsheet 24, an acquisition layer 52, a portion of a core wrap 160,
or an additional layer (e.g., a carrier layer 170) may be a
different color than a different one of the topsheet 24, the
acquisition layer 52, the portion of the core wrap 160, or the
additional layer.
[0258] In another instance, in an absorbent article 20, one of a
portion of a topsheet 24, a portion of an acquisition layer 52, a
portion of a core wrap 160, or a portion of an additional layer may
be a different color than a different one of the portion of the
topsheet 24, the portion of the acquisition layer 52, the portion
of the core wrap 160, or the portion of the additional layer.
[0259] In another instance, in an absorbent article 20, a first
portion of one of a topsheet 24, an acquisition layer 52, a portion
of a core wrap 160, or an additional layer may be a different color
as a second portion of the same one of the topsheet 24, the
acquisition layer 52, the core wrap 160, or the additional
layer.
[0260] The process of the present disclosure may comprise applying
the indicia to or positioning or printing the indicia on the
topsheet 24, the acquisition layer 52, the carrier layer 17, a
portion of the core wrap 160, and/or an additional layer positioned
at least partially intermediate the topsheet 24 and the backsheet
25. The indicia may be positioned or printed on or applied to
either side of the topsheet 24, the acquisition layer 52, the
carrier layer 17, the portion of the core wrap 160, and/or the
additional layer positioned at least partially intermediate the
topsheet 24 and the backsheet 25. If the indicia is applied to or
positioned or printed on the topsheet 24 or the acquisition layer
52, this step may be done before or after the topsheet 24 and the
acquisition layer 52 are simultaneously mechanically deformed and
combined together to provide the topsheet/acquisition layer
laminate 245.
[0261] In some forms, the indicia may be positioned or printed on
or applied to a carrier layer 17 that comprises pulp fibers. In
other forms, the indicia may be positioned or printed on or applied
to a garment-facing surface or a wearer-facing surface of the
acquisition layer 52. In some instances, the materials suitable for
indicia placement may be purchased with indicia thereon or the
indicia may be applied to or printed or positioned on before or
during feeding these materials into an absorbent article
manufacturing line.
Precursor Materials for the Topsheet and the Acquisition Layer
[0262] The topsheet/acquisition layer laminate 245 of the present
invention can be made of any suitable nonwoven materials
("precursor materials"). In some cases, the topsheet/acquisition
layer laminate 245 may also be free of cellulose materials. The
precursor materials for the topsheet/acquisition layer laminate 245
may have suitable properties in order to be deformed. The suitable
properties of the precursor materials may include: apparent
elongation of the fibers, fiber mobility, ability to deform and
stretch in the area where the three-dimensional protrusions 250 of
the topsheet/acquisition layer laminate 245 are formed. Hence, the
precursor materials are capable of undergoing mechanical
deformation to ensure that the three-dimensional protrusion 250
will not tend to recover or return to the prior configuration of a
flat topsheet 24 laminated on a flat acquisition layer 52.
[0263] Several examples of nonwoven materials suitable for use as a
topsheet 24 for the topsheet/acquisition layer laminate 245 may
include, but are not limited to: spunbonded nonwovens; carded
nonwovens; and nonwovens with relatively specific properties to be
able to be readily deformed.
[0264] One suitable nonwoven material as a topsheet 24 for the
topsheet/acquisition layer laminate 245 may be an extensible
polypropylene/polyethylene spunbonded nonwoven. One suitable
nonwoven material as a topsheet 24 for the topsheet/acquisition
layer laminate 245 may be a spunbonded nonwoven comprising
polypropylene and polyethylene. The fibers may comprise a blend of
polypropylene and polyethylene. Alternatively, the fibers may
comprise bicomponent fibers, such as a sheath-core fiber with
polyethylene on the sheath and polypropylene in the core of the
fiber.
[0265] The topsheet 24 of the topsheet/acquisition layer laminate
245 may have a basis weight from 8 to 40 gsm or from 8 to 30 gsm or
from 8 to 20 gsm.
[0266] Suitable nonwoven materials for the acquisition layer 52 of
the topsheet/acquisition layer laminate 245 may include, but are
not limited to: spunbonded nonwovens, through-air bonded ("TAB")
carded high loft nonwoven materials, spunlace nonwovens,
hydroentangled nonwovens, and resin bonded carded nonwoven
materials.
[0267] Spunbonded PET may be denser than carded nonwovens,
providing more uniformity and opacity. Since PET fibers are not
very extensible, the nonwoven can be bonded such that at least some
of the fibers can be separated easily from the bond sites to allow
the fibers to pull out of the bond sites and rearrange when the
material is strained. This type of bonding, e.g. pressure bonding
can help increasing the level of mobility of the fibers. Indeed,
the fibers tend to pull out from the bond sites under tension.
[0268] The acquisition layer exhibits a basis weight from 10 to 120
gsm or from 10 to 100 gsm or from 10 to 80 gsm.
[0269] The topsheet 24 and/or acquisition layer 52 may have a
density from 0.01 to 0.4 g/cm.sup.3 or from 0.01 to 0.25 g/cm.sup.3
or from 0.04 to 0.15 g/cm.sup.3.
[0270] The topsheet 24 and acquisition layer 52 may be joined
together prior or during the mechanical deformation. If desired an
adhesive, chemical bonding, resin or powder bonding, or thermal
bonding between the topsheet 24 and acquisition layer 52 may be
selectively utilized to bond certain regions or all of the topsheet
24 and acquisition layer 52 together. In addition, the topsheet 24
and acquisition layer 52 may be bonded during processing, for
example, by carding the topsheet 24 of onto the acquisition layer
52 and thermal point bonding the combined layers.
[0271] Prior to any mechanical deformation, the topsheet 24 may be
attached to the acquisition layer 52. For instance, the topsheet 24
may be attached to the acquisition layer 52 where the topsheet 24
and acquisition layer 52 overlaps. The attachment of the topsheet
24 to the acquisition layer 52 may include a uniform continuous
layer of adhesive, a discontinuous patterned application of
adhesive or an array of separate lines, spirals, or spots of
adhesive. The basis weight of the adhesive in the
topsheet/acquisition layer laminate 245 may be from 0.5 to 30 gsm
or from 1 to 10 gsm or from 2 to 5 gsm.
Materials for the Carrier Layer
[0272] The carrier layer 17 may be selected from the group
consisting of nonwovens, tissues, or films and combinations
thereof.
[0273] Examples of a nonwoven web used for the carrier layer 17 may
include various types of known nonwoven webs such as a spunbonded
nonwoven web, a meltblown nonwoven web, and a
spunbond-meltblown-spunbond nonwoven web. These nonwoven webs are
made of thermoplastic polymers.
[0274] A material for fibers composing the nonwoven web used for
the carrier layer 17 may include various types of known fibers such
as polyethylene, polypropylene, polyester, and acryl, conjugate
fibers such as polyethylene/polypropylene,
polyethylene/polyethylene terephthalate, and
polypropylene/polyethylene terephthalate, i.e., fibers formed of
core-in-sheath fibers and side-by-side fibers. The fibers may be
used alone or in combination. Further, the carrier layer 17 may
have a monolayer structure or a multilayer structure.
[0275] The carrier layer 17 may comprise a tissue made of wet-laid
fibers comprising cellulose fibers having a Wet burst Strength from
50 to 500 g according to the Wet Burst Strength Test Method and
combinations thereof.
[0276] The carrier layer 17 may be treated with a surfactant to
render the carrier layer 17 hydrophilic. The carrier layer 17 may
be made of one material of the group as set out above, which has
been chemically modified to render it hydrophilic. The hydrophilic
carrier layer 17 may thus improve the transfer of the liquid bodily
exudates from the distribution layer 54 to the absorbent core 28 of
the absorbent article 20.
[0277] The carrier layer 17 may have a basis weight of at least 5
gsm to 60 gsm or at least 5 gsm to 20 gsm or at least 5 to 15
gsm.
[0278] The carrier layer 17 may be wider and longer than the
distribution layer 54. The carrier layer can help preventing the
fibers 540 of the dry-laid fibrous structure getting to the skin of
the wearer when the distribution layer 54 comprises the dry-laid
fibrous structure and if the topsheet/acquisition layer laminate
245 comprises some holes.
[0279] The carrier layer 17 may be colored. Color may be imparted
to the carrier layer 17 by color pigmentation. The term "color
pigmentation" encompasses any pigments suitable for imparting a
non-white color to the carrier layer 17. This term therefore does
not include "white" pigments such as TiO.sub.2 which are typically
added to the layers of conventional absorbent articles to impart
them with a white appearance. Pigments are usually dispersed in
vehicles or substrates for application, as for instance in inks,
paints, plastics or other polymeric materials.
[0280] The pigments may for example be introduced in a
polypropylene masterbatch. A masterbatch comprises a high
concentration of pigment and/or additives which are dispersed in a
carrier medium which can then be used to pigment or modify the
virgin polymer material into a pigmented bicomponent nonwoven. An
example of suitable colored masterbatch material that can be
introduced is Pantone color 270 Sanylen violet PP 42000634 ex
Clariant, which is a PP resin with a high concentration of violet
pigment. Typically, the amount of pigments introduced by weight of
the carrier layer 17 may be of from 0.3%-2.5%.
[0281] Alternatively, color may be imparted to the carrier layer 17
by way of impregnation of a colorant into the substrate. Colorants
such as dyes, pigments, or combinations may be impregnated in the
formation of substrates such as polymers, resins, or nonwovens. For
example, the colorant may be added to molten batch of polymer
during film, fiber, or filament formation.
[0282] When viewing the absorbent article from the topsheet, the
colored carrier layer 17 may provide to a caregiver an enhanced
impression of depth to support to the impression given by the
three-dimensional protrusions 250 as such, as long as the colored
carrier layer 17 are visible from the topsheet 24. Hence, a colored
carrier layer 17 can support the caregiver's perception that the
absorbent article is well able to absorb the liquid bodily
exudates.
[0283] The topsheet 24 and/or acquisition layer 52 of the
topsheet/acquisition layer laminate 245 may be colored, for the
same reasons.
[0284] The carrier layer 17 may be porous, may have a relatively
high permeability and have a relatively high level of saturation
when exposed to fluid under suction pressures, e.g. of 20 cm of
water. The relatively high level of saturation of the carrier layer
17 can be defined as the ratio between the volume of liquid bodily
exudates in the pores of the carrier layer 17 and the total void
volume of the carrier layer 17. The carrier layer 17 can help
providing connectivity between the acquisition layer 52 of the
topsheet/acquisition layer laminate 245 and the distribution layer
54.
[0285] Also, the carrier layer 17 may comprise some relative small
sized holes such that the fibers 540 of the dry-laid fibrous
structure of the distribution layer 54 may partially pass through
the holes of the carrier layer. Hence, the dry-laid fibrous
structure 540 can entangle and contact the acquisition layer 52 of
the topsheet/acquisition layer laminate 245. The carrier layer 17
may comprise holes having a size from 0.02 mm to 10 mm.
EXAMPLES
[0286] Any densities of the topsheet or the acquisition layer
materials are provided at 2.1 kPa.
Comparative Example 1
[0287] Neither the topsheet nor the acquisition layer has been
mechanically deformed. The topsheet and the acquisition layer were
attached to each other with a hot melt adhesive applied in form of
spirals with a basis weight of 5 gsm. The acquisition layer was
centered onto the topsheet with respect to the topsheet and placed
50 mm from the front MD edge of the topsheet. The topsheet and
acquisition layer attached together form a composite web.
[0288] The topsheet was a hydrophilic coated mono component high
elongation spunbond polypropylene (HES PP) nonwoven material with a
density of 0.11 g/cm.sup.3. The mono component HES PP nonwoven
material for the topsheet has an overall basis weight of 20 gsm.
The mono component HES PP nonwoven material was first coated with a
finish made of a fatty acid polyethylene glycol ester for the
production of a permanent hydrophilic mono component HES PP
nonwoven material. The topsheet of the topsheet/acquisition layer
laminate had a width of 168 mm and a length of 488 mm.
[0289] The acquisition layer was an air through bonded nonwoven
with a basis weight of 65 gsm with a density of 0.09 g/cm.sup.3.
The acquisition layer comprises 4 denier coPET/PET (polyethylene
terephthalate) bicomponent fibers. The acquisition layer of the
topsheet/acquisition layer laminate had a width of 90 mm and a
length of 338 mm.
[0290] The topsheet and acquisition layer have been attached to
each other with a hot melt adhesive applied in form of spirals with
a basis weight of 5 gsm.
Example 1
[0291] The topsheet and the acquisition layer were attached to each
other with a hot melt adhesive applied in form of spirals with a
basis weight of 5 gsm. The acquisition layer was centered onto the
topsheet with respect to the topsheet and placed 50 mm from the
front MD edge of the topsheet. The topsheet and acquisition layer
attached together form a composite web.
[0292] The topsheet and acquisition layer have been simultaneously
mechanically deformed by passing them between a pair of
intermeshing male and female rolls to provide a
topsheet/acquisition layer laminate. The topsheet of the
topsheet/acquisition layer laminate was in contact with the male
roll. The acquisition layer of the topsheet/acquisition layer
laminate was in contact with the female roll. The teeth on the male
roll have a rounded diamond shape like that shown in FIG. 14A, with
vertical sidewalls and a radiused or rounded edge at the transition
between the top and the sidewalls of the tooth. The teeth are 0.186
inch (4.72 mm) long and 0.125 inch (3.18 mm) wide with a CD spacing
of 0.150 inch (3.81 mm) and an MD spacing of 0.346 inch (8.79 mm)
The recesses in the mating female roll also have a rounded diamond
shape, similar to that of the male roll, with a clearance between
the rolls of 0.032-0.063 inch (0.813-1.6 mm) The process speed was
800 fpm and the depth of engagement (DOE) was 0.155 inch (3.94 mm),
with the topsheet being in contact with the male roll and the
acquisition layer being in contact with the female roll.
[0293] The topsheet of the topsheet/acquisition layer laminate was
a hydrophilic coated mono component high elongation spunbond
polypropylene (HES PP) nonwoven material with a density of 0.11
g/cm.sup.3. The mono component HES PP nonwoven material for the
topsheet has an overall basis weight of 20 gsm. The mono component
HES PP nonwoven material was first coated with a finish made of a
fatty acid polyethylene glycol ester for the production of a
permanent hydrophilic mono component HES PP nonwoven material. The
topsheet of the topsheet/acquisition layer laminate had a width of
168 mm and a length of 488 mm.
[0294] The acquisition layer of the topsheet/acquisition layer
laminate was an air through bonded nonwoven with a basis weight of
65 gsm with a density of 0.09 g/cm.sup.3. The acquisition layer
comprises 4 denier coPET/PET (polyethylene terephthalate)
bicomponent fibers which was treated with a surfactant. The
acquisition layer of the topsheet/acquisition layer laminate had a
width of 90 mm and a length of 338 mm.
[0295] The topsheet and acquisition layer have been attached to
each other with a hot melt adhesive applied in form of spirals with
a basis weight of 5 gsm.
Comparative Example 2
[0296] The topsheet and the acquisition layer were attached to each
other with a hot melt adhesive applied in form of spirals with a
basis weight of 5 gsm. The acquisition layer was centered onto the
topsheet with respect to the topsheet and placed 50 mm from the
front MD edge of the topsheet. The topsheet and acquisition layer
attached together form a composite web. Neither the topsheet nor
the acquisition layer have been mechanically deformed.
[0297] The topsheet was a hydrophilic coated mono component high
elongation spunbond polypropylene (HES PP) nonwoven material with a
density of 0.11 g/cm.sup.3. The mono component HES PP nonwoven
material for the topsheet has an overall basis weight of 20 gsm.
The mono component HES PP nonwoven material was first coated with a
finish made of a fatty acid polyethylene glycol ester for the
production of a permanent hydrophilic mono component HES PP
nonwoven material. The topsheet of the topsheet/acquisition layer
laminate had a width of 168 mm and a length of 488 mm.
[0298] The acquisition layer was a spunbond nonwoven with a basis
weight of 60 gsm with a density of 0.13 g/cm.sup.3. The acquisition
layer comprises 7 denier PET/coPET (polyethylene terephthalate)
trilobal bicomponent fibers with a 70/30 ratio of PET/coPET which
has been treated with a surfactant. The acquisition layer of the
topsheet/acquisition layer laminate had a width of 90 mm and a
length of 338 mm.
Example 2
[0299] The topsheet and the acquisition layer were attached to each
other with a hot melt adhesive applied in form of spirals with a
basis weight of 5 gsm. The acquisition layer was centered onto the
topsheet with respect to the topsheet and placed 50 mm from the
front MD edge of the topsheet. The topsheet and acquisition layer
attached together form a composite web. The topsheet and
acquisition layer attached together have been simultaneously
mechanically deformed by passing them between a pair of
intermeshing male and female rolls. The topsheet of the
topsheet/acquisition layer laminate was in contact with the male
roll. The acquisition layer of the topsheet/acquisition layer
laminate was in contact with the female roll. The teeth on the male
roll have a rounded diamond shape like that shown in FIG. 14A, with
vertical sidewalls and a radiused or rounded edge at the transition
between the top and the sidewalls of the tooth. The teeth are 0.186
inch (4.72 mm) long and 0.125 inch (3.18 mm) wide with a CD spacing
of 0.150 inch (3.81 mm) and an MD spacing of 0.346 inch (8.79 mm)
The recesses in the mating female roll also have a rounded diamond
shape, similar to that of the male roll, with a clearance between
the rolls of 0.032-0.063 inch (0.813-1.6 mm) The process speed was
800 fpm and the depth of engagement (DOE) was 0.155 inch (3.94 mm),
with the topsheet being in contact with the male roll and the
acquisition layer being in contact with the female roll.
[0300] The topsheet of the topsheet/acquisition layer laminate was
a hydrophilic coated mono component high elongation spunbond
polypropylene (HES PP) nonwoven material with a density of 0.11
g/cm.sup.3. The mono component HES PP nonwoven material for the
topsheet has an overall basis weight of 20 gsm. The mono component
HES PP nonwoven material was first coated with a finish made of a
fatty acid polyethylene glycol ester for the production of a
permanent hydrophilic mono component HES PP nonwoven material. The
topsheet of the topsheet/acquisition layer laminate had a width of
168 mm and a length of 488 mm.
[0301] The acquisition layer of the topsheet/acquisition layer
laminate was a spunbond nonwoven with a basis weight of 60 gsm with
a density of 0.13 g/cm.sup.3. The acquisition layer comprises 7
denier PET/coPET (polyethylene terephthalate) trilobal bicomponent
fibers with a 70/30 ratio of PET/coPET which has been treated with
a surfactant. The acquisition layer of the topsheet/acquisition
layer laminate had a width of 90 mm and a length of 338 mm.
Prototype Diapers for the Examples
[0302] Diaper prototypes for the above Example were produced using
Pampers Active Fit S4 (size 4) diaper commercially available in
Germany in November 2014. Pampers Active Fit S4 (size 4) diaper
comprises a topsheet, an acquisition layer beneath the topsheet, a
distribution layer beneath the acquisition layer, an absorbent core
between the distribution and a backsheet beneath the absorbent
core. Diaper prototypes for the above Comparative Examples and
Examples were produced using Pampers Active Fit S4 (size 4)
diaper.
[0303] The topsheet and acquisition layer attached together for
each comparative example and for each example were placed on top of
a Pampers Active Fit diaper commercially available in Germany in
November 2014 from where the commercial topsheet and acquisition
layer were removed while keeping the distribution layer in place.
For each diaper prototype based on Examples 1 and 2, the
topsheet/acquisition layer laminate were placed on top of the
distribution layer with the three-dimensional protrusions
protruding towards the backsheet.
[0304] The acquisition layer front edge is placed 10 mm from the
distribution layer front edge. The topsheet/acquisition layer
laminate was attached onto the distribution layer and the absorbent
core with a hot melt adhesive applied all over the side of the
topsheet/acquisition layer laminate facing the distribution layer.
The hot melt adhesive was applied in form of spirals with a basis
weight of 5 gsm.
[0305] The three-dimensional protrusions of the
topsheet/acquisition layer laminate of each Examples 1 and 2 were
protruding towards the backsheet because the topsheet of the
topsheet/acquisition layer laminate was in contact with the male
roll, as set out above.
[0306] Each prototype diaper was compacted in a bag at an In Bag
Stack Height, i.e. the total caliper of 10 bi-folded diapers, of 90
mm for 1 week. Then the bag was opened and the diapers out of the
bag were conditioned at least 24 hours prior to any testing at
23.degree. C.+/-2.degree. C. and 50%+/-10% Relative Humidity
(RH).
Experimental Results
[0307] The data have been measured according to the respective test
methods as disclosed herein.
TABLE-US-00001 Examples Comp. Example 1 Example 1 mech. deformed:
mech. deformed: No Yes Std. Std. TS/AQL layer laminate Value Dev.
Value Dev. Total acquisition time [s] 243 25 212 26 Rewet value
[mg] 183 23 173 8 Liquid in topsheet value [mg] 166 27 118 20
Topsheet load [g/g] 0.9 0.17 0.46 0.07 Measured protrusion height
(mm) n.a* n.a* 1.40 0.10 Measured protrusion base width n.a* n.a*
3.40 0.30 (mm) Examples Comp. Example 2 Example 2 mech. deformed:
mech. deformed: No Yes Std. Std. TS/AQL layer laminate Value Dev.
Value Dev. Total acquisition time [s] 340 87 268 20 Rewet value
[mg] 89 25 85 11 Liquid in topsheet value [mg] 23 4 77 10 Topsheet
load [g/g] 0.13 0.03 0.26 0.04 Measured protrusion height (mm) n.a*
n.a* 1.20 0.20 Measured protrusion base width n.a* n.a* 3.20 0.40
(mm) n.a.*: not applicable as not measurable
[0308] Both comparative examples 1 and 2 lack on three-dimensional
protrusions.
Example 1 Versus Comparative Example 1
The Acquisition Layer is an Air Bonded Through Nonwoven
[0309] In Example 1, simultaneously mechanically deforming the
topshet and the acquisition layer together to form a
topsheet/acquisition layer laminate enables to introduce a
plurality of three-dimensional protrusions (measured protrusion
height and measured protrusion base width) while providing dryness
benefit in terms of liquid in topsheet, Topsheet Load and rewet
values without total acquisition time loss, when compared to the
Comparative Example 1. Without being bound to theory, the technical
dryness improvement of Example 1 versus Comparative Example 1 is
basically due to the better and more intimate contact between the
topsheet and the acquisition layer as result of the simultaneous
mechanical deformation of the topsheet and the acquisition layer
together.
Example 2 Versus Comparative Example 2
The Acquisition Layer is a Spunbond Nonwoven
[0310] In Example 2, simultaneously mechanically deforming the
topshet and the acquisition layer together to form a
topsheet/acquisition layer laminate enables to introduce a
plurality of three-dimensional protrusions (measured protrusion
height and measured protrusion width) providing the benefit of
reducing the total acquisition time when compared to the
Comparative Example 2. Without being bound to theory, the
acquisition speed benefit is due to the additional void volume
generated as result of the simultaneous mechanical deformation of
the topsheet and the acquisition layer together.
[0311] Each Example 1 and 2 of the present invention includes a
plurality of three-dimensional protrusions while the respective
Comparative Examples 1 and 2 lack on three-dimensional protrusions.
Hence, a topsheet/acquisition layer laminate comprising
three-dimensional protrusions can help to improve the fluid
handling properties of the absorbent article. Additionally a
topsheet/acquisition layer laminate comprising three-dimensional
protrusions can help to improve dryness and absorption perception
of the absorbent article by the caregiver.
Test Methods
[0312] Unless indicated otherwise, all tests described herein are
made with samples conditioned at least 24 hours at 23.degree.
C.+/-2.degree. C. and 50%+/-10% Relative Humidity (RH). Densities
are referred at 2.1 kPa.
General Sample Preparation:
[0313] For the Fixed Height Frit Absorption (FHFA) at 20 cm or at 0
cm, a disc sample of the whole topsheet/acquisition layer laminate
has to be prepared. For this, the center of the annular sample
coincides with center of the topsheet/acquisition layer laminate.
The intersection of the longitudinal and transversal axis of the
topsheet/acquisition layer laminate defines the center of the
topsheet/acquisition layer laminate.
Wet Burst Test Method
[0314] The Wet Burst Strength as used herein is a measure of the
ability of a fibrous structure to absorb energy, when wet and
subjected to deformation with regard to the plane of the fibrous
structure.
[0315] The wet burst strength of a fibrous structure (referred to
as "sample" within this test method) is determined using an
electronic burst tester and specified test conditions. The results
obtained are averaged out of 4 experiments and the wet burst
strength is reported for a fibrous structure 55 consisting of one
single layer of wet-laid fibers.
Equipment
[0316] Apparatus: Burst Tester--Thwing-Albert Vantage Burst Tester
or equivalent ball burst instrument where the ball moves downward
during testing. Refer to manufacturer's operation and set-up
instructions. The ball diameter is 1.59 cm and the clamp opening
diameter is 8.9 cm. [0317] Calibration Weights--Refer to
manufacturer's Calibration instructions [0318] Conditioned Room
Temperature and Humidity controlled within the following limits for
Laboratory testing: [0319] Temperature: 23.degree..+-.1.degree. C.
[0320] Relative humidity: 50%.+-.2% [0321] Paper Cutter--Cutting
board, 600 mm size [0322] Scissors--100 mm, or larger [0323]
Pan--Approximate Width/Length/Depth: 240.times.300.times.50 mm, or
equivalent [0324] Distilled water at the temperature of the
conditioned room used
Sample Preparation
[0325] The fibrous structure 55 may be unwound from the roll.
[0326] The samples to be tested are conditioned in the conditioned
room for 24 hours immediately before testing. All testing occurs
within the conditioned room.
[0327] Cut the samples so that they are approximately 228 mm in
length and width of approximately 140 mm in width.
Operation
[0328] Set-up and calibrate the Burst Tester instrument according
to the manufacturer's instructions for the instrument being
used.
[0329] Holding the sample by the narrow edges, the center of the
sample is dipped into a pan filled approximately 25 mm from the top
with distilled water. The sample is left in the water for 4
(.+-.0.5) seconds.
[0330] The excess water is drained from the sample for 3 (.+-.0.5)
seconds holding the sample in a vertical position.
[0331] The test should proceed immediately after the drain step.
The sample should have no perforations, tears or imperfections in
the area of the sample to be tested. If it does, start the test
over.
[0332] The sample is placed between the upper and lower rings of
the Burst Tester instrument. The sample is positioned centered and
flat on the lower ring of the sample holding device in a manner
such that no slack in the sample is present.
[0333] The upper ring of the pneumatic holding device is lowered to
secure the sample.
[0334] The test is started. The test is over at sample failure
(rupture) i.e., when the load falls 20 g from the peak force. The
maximum force value is recorded.
[0335] The plunger will automatically reverse and return to its
original starting position.
[0336] The upper ring is raised in order to remove and discard the
tested sample.
[0337] The procedure is repeated until all replicates have been
tested.
Calculation
Wet Burst Strength=sum of peak load readings/number of replicates
tested
[0338] Report the Wet Burst results to the nearest gram.
Accelerated Compression Method
[0339] 1. Cut 10 samples of the topsheet/acquisition layer laminate
245 (called herein specimen) to be tested and 11 samples of paper
towel into a 3 inch.times.3 inch (7.6 cm.times.7.6 cm) square.
[0340] 2. Measure the caliper of each of the 10 specimens at 2.1
kPa and a dwell time of 2 seconds using a Thwing-Albert ProGage
Thickness Tester or equivalent with a 50-60 millimeter diameter
circular foot. Record the pre-compression caliper to the nearest
0.01 mm. [0341] 3. Alternate the layers of the specimens to be
tested with the paper towels, starting and ending with the paper
towels. The choice of paper towel does not matter and is present to
prevent "nesting" of the protrusions in the deformed samples. The
samples should be oriented so the edges of each of the specimens
and each of the paper towels are relatively aligned, and the
protrusions in the specimens are all oriented the same direction.
[0342] 4. Place the stack of samples into a 40.degree. C. oven and
place a weight on top of the stack. The weight must be larger than
the foot of the thickness tester. To simulate high pressures or low
in-bag stack heights, apply 35 kPa (e.g. 17.5 kg weight over a
70.times.70 mm area). To simulate low pressures or high in-bag
stack heights, apply 7 kPa (e.g. 3.5 kg weight over a 70.times.70
mm area). [0343] 5. Leave the samples in the oven for 15 hours.
After the time period has elapsed, remove the weight from the
samples and remove the samples from the oven. [0344] 6. Within 30
minutes of removing the samples from the oven, measure the
post-compression caliper as directed in step 2 above, making sure
to maintain the same order in which the pre-compression caliper was
recorded. Record the post-compression caliper of each of the 10
specimens to the nearest 0.01 mm. [0345] 7. Let the samples rest at
23.+-.2.degree. C. and at 50.+-.2% relative humidity for 24 hours
without any weight on them. [0346] 8. After 24 hours, measure the
post-recovery caliper of each of the 10 specimens as directed in
step 2 above, making sure to maintain the same order in which the
pre-compression and post-compression calipers were recorded. Record
the post-recovery caliper of each of the 10 specimens to the
nearest 0.01 mm. Calculate the amount of caliper recovery by
subtracting the post-compression caliper from the post-recovery
caliper and record to the nearest 0.01 mm. [0347] 9. If desired, an
average of the 10 specimens can be calculated for the
pre-compression, post-compression and post-recovery calipers.
Protrusion Base Width and Protrusion Height Test Methods
[0348] 1) General Information
[0349] The Measured Protrusion Base Width and Measured Protrusion
Height of the three-dimensional protrusions of the
topsheet/acquisition layer laminate of an absorbent article are
measured using a GFM Primos Optical Profiler instrument
commercially available from GFMesstechnik GmbH, WarthestraBe 21,
D14513 Teltow/Berlin, Germany. Alternative suitable non-touching
surface topology profilers having similar principles of measurement
and analysis, can also be used, here GFM Primos is exemplified.
[0350] The GFM Primos Optical Profiler instrument includes a
compact optical measuring sensor based on a digital micro mirror
projection, consisting of the following main components: [0351] a)
DMD projector with 800.times.600 direct digital controlled
micro-mirrors [0352] b) CCD camera with high resolution
(640.times.480 pixels) [0353] c) Projection optics adapted to a
measuring area of at least 30.times.40 mm [0354] d) Recording
optics adapted to a measuring area of at least 30.times.40 mm
[0355] e) A table tripod based on a small hard stone plate [0356]
f) A cold light source (an appropriate unit is the KL 1500 LCD,
Schott North America, Inc., Southbridge, Mass.) [0357] g) A
measuring, control, and evaluation computer running ODSCAD 6.3
software
[0358] Turn on the cold-light source. The settings on the
cold-light source are set to provide a color temperature of at
least 2800K.
[0359] Turn on the computer, monitor, and open the image
acquisition/analysis software. In the Primos Optical Profiler
instrument, select "Start Measurement" icon from the ODSCAD 6.3
task bar and then click the "Live Image button".
[0360] The instrument is calibrated according to manufacturer's
specifications using calibration plates for lateral (X-Y) and
vertical (Z). Such Calibration is performed using a rigid solid
plate of any non-shiny material having a length of 11 cm, a width
of 8 cm and a height of 1 cm. This plate has a groove or machined
channel having a rectangular cross-section, a length of 11 cm, a
width of 6.000 mm and an exact depth of 2.940 mm. This groove is
parallel to the plate length direction. After calibration, the
instrument must be able to measure the width and depth dimensions
of the groove to within .+-.0.004 mm.
[0361] All testing is performed in a conditioned room maintained at
23.+-.2.degree. C. and 50+/-10% relative humidity. The surface to
be measured may be lightly sprayed with a very fine white powder
spray. Preferably, the spray is NORD-TEST Developer U 89, available
from Helling GmbH, Heidgraben, Germany.
[0362] 2) Protrusion Base Width Test Method
[0363] The topsheet/acquisition layer laminate is extracted from
the absorbent article by attaching the absorbent article to a flat
surface in a taut planar (i.e. stretched planar) configuration with
the topsheet of the topsheet/acquisition layer laminate facing up.
Any leg or cuff elastics are severed in order to allow the
absorbent article to lie flat. Using scissors, two longitudinal
cuts are made through all layers above the absorbent core (i.e. the
core wrap) along the edges of the topsheet/acquisition layer
laminate. Two transversal cuts are made through the same layers
following the front and back waist edges of the absorbent
article.
[0364] The topsheet/acquisition layer laminate and any other layers
above the absorbent core are then removed without perturbing the
topsheet/acquisition layer laminate. Freeze spray (e.g. CRC Freeze
Spray manufactured by CRC Industries, Inc. 885 Louis Drive,
Warminster, Pa. 18974, USA), or equivalent aid may be used to
facilitate removal of the uppermost layers from the absorbent
article. The topsheet/acquisition layer laminate is then separated
from any other layers, including any carrier layer (e.g. a nonwoven
carrier layer, a tissue layer), using freeze spray if necessary. If
a distribution layer, e.g. a pulp containing layer is attached to
the topsheet/acquisition layer laminate, any residual cellulose
fibers are carefully removed with tweezers without modifying the
acquisition layer.
[0365] The topsheet/acquisition layer laminate with
three-dimensional protrusions (conditioned at a temperature of
23.degree. C..+-.2.degree. C. and a relative humidity of 50%.+-.10%
for at least 24 hours) namely "the specimen" is laid down on a hard
flat horizontal surface with the body-facing side upward, i.e. the
topsheet of the topsheet/acquisition layer laminate being upward.
Ensure that the specimen is lying in planar configuration, without
being stretched, with the specimen uncovered.
[0366] A nominal external pressure of 1.86 kPa (0.27 psi) is then
applied to the specimen. Such nominal external pressure is applied
without interfering with the topology profile measurement. Such an
external pressure is applied using a transparent, non-shining flat
Plexiglas.RTM. plate 200 mm by 70 mm and appropriate thickness
(approximately 5 mm) to achieve a weight of 83 g. The plate is
gently placed on top of the specimen, such that the center point of
the Plexiglas.RTM. plate is at least 40 mm away from any folds,
with the entire plate resting on the specimen. A fold corresponds
to a part of the absorbent article (e.g. the topsheet/acquisition
layer laminate) where the absorbent article has been folded for
packaging purposes.
[0367] Two 50 mm.times.70 mm metal weights each having a mass of
1200 g (approximate thickness of 43 mm) are gently placed on the
Plexiglas.RTM. plate such that a 70 mm edge of each metal weight is
aligned with the 70 mm edges of the Plexiglas.RTM. plate. A metal
frame having external dimensions of 70 mm.times.80 mm and interior
dimensions of 42 mm.times.61 mm, and a total weight of 142 g
(approximate thickness 6 mm), is positioned in the center of the
Plexiglas.RTM. plate between the two end weights with the longest
sides of the frame aligned with the longest sides of the plate.
[0368] If the specimen is smaller than 70.times.200 mm, or if a
large enough area without a fold is not present, or if an area of
interest is close to the edges of the specimen and can't be
analyzed with the Plexiglas and weights settings described above,
then the X-Y dimensions of the Plexiglas.RTM. plate and the added
metal weights may be adjusted to reach a nominal external pressure
of 1.86 kPa (0.27 psi) while maintaining a minimum 30.times.40 mm
field of view. At least 10 complete three-dimensional protrusions
of the specimen should be captured in the field of view of 30
mm.times.40 mm.
[0369] Position the projection head to be normal to the specimen
surface (i.e. to the topsheet of the topsheet/acquisition layer
laminate).
[0370] Adjust the distance between the specimen and the projection
head for best focus.
[0371] In the Primos Optical Profiler instrument, turn on the
button "Pattern" to make a red cross appear on the screen ross and
a black cross appears on the specimen.
[0372] Adjust the focus control until the black cross is aligned
with the red cross on the screen.
[0373] Adjust image brightness then capture a digitized image.
[0374] In the Primos Optical Profiler instrument, change the
aperture on the lens through the hole in the side of the projector
head and/or altering the camera "gain" setting on the screen.
[0375] When the illumination is optimum, the red circle at the
bottom of the screen labeled "I.O." will turn green.
[0376] Click on the "Measure" button.
[0377] The topology of the upper surface of the
topsheet/acquisition layer laminate specimen is measured through
the Plexiglas plate over the entire field of view 30 mm.times.40
mm. It is important to keep the specimen still stationary during
this time in order to avoid blurring of the captured image. The
image should be captured within the 30 seconds following the
placement of the Plexiglas plate, metal weights and frame on top of
the specimen.
[0378] After the image has been captured, the X-Y-Z coordinates of
every pixel of the 40 mm.times.30 mm field of view area are
recorded. The X direction is the direction parallel to the longest
edge of the rectangular field of view, the Y direction is the
direction parallel to the shortest edge of the rectangular field of
view. The Z direction is the direction perpendicular to the X-Y
plane. The X-Y plane is horizontal while the Z direction is
vertical, i.e. orthogonal to the X-Y plane.
[0379] These data are smoothed and filtered using a polynomial
filter (n=6), a median filter 11 pixels by 11 pixels, and a
structure filter 81 pixels by 81 pixels. The polynomial filter
(n=6) approximates the X-Y-Z coordinate surface with a polynomial
of order 6 and returns the difference to the approximated
polynomial. The median filter 11 pixels by 11 pixels divides the
field of view (40 mm.times.30 mm) in X-Y squares of 11 pixels by 11
pixels. The Z coordinate of the pixel located at the center of a
given 11 pixels by 11 pixels square will be replaced by the mean Z
value of all the pixels of this given square. The structure filter
81 pixels by 81 pixels, removes the waviness of the structure and
translates all the Z peak values belonging to the bottom surface of
the Plexiglas plate to a top X-Y plane.
[0380] A Reference Plane is then defined as the X-Y plane
intercepting the surface topology profile of the entire field of
view (i.e. 30 mm.times.40 mm), 100 microns below this top X-Y
plane. In the Primos Optical Profiler instrument, to measure the
Material Area of the Reference Plane (Z=-0.1 mm), click on the
button "Evaluate". Then, apply a pre-filtering routine including a
polynomial filter (n=6), a median filter 11 by 11 and a structure
filter (n=81) using the function "Filter". Save the image to a
computer file with ".omc" extension.
[0381] The same above procedure is then executed on the
topsheet/acquisition layer laminate with the garment-facing side
upward (i.e. the acquisition layer of the topsheet/acquisition
layer laminate being upward), the 40 mm.times.30 mm field of view
being located at the exact same X-Y position of the
topsheet/acquisition layer laminate.
[0382] The Empty Area of the reference plane can be defined as the
area of the Reference Plane that is above the surface profile. The
Empty Areas having boundaries strictly located inside the field of
view area (i.e. 30 mm.times.40 mm) without crossing or overlapping
with the boundaries of the field of view area (i.e. 40 mm.times.30
mm) are defined as Isolated Empty Area(s). The Measured Protrusion
Base Width is defined for an Isolated Empty Area as the diameter of
the biggest circle that can be inscribed inside a given Isolated
Empty Area. This circle should only overlap with the Isolated Empty
Area.
[0383] In the Primos Optical Profiler instrument, this can be done
by clicking on "Draw circle" and drawing the biggest inscribed
circle possible in a chosen Isolated Empty Area. Click on "Show
sectional picture", the circle diameter can be measure via clicking
on the extremity of the sectional picture profile and then clicking
on "Horizontal distance" to obtain the Protrusion Base Width.
[0384] For both of the acquired and digitized images, the
Protrusion Base Width of all the Isolated Empty Areas is
determined. Then, the Measured Protrusion Base Width is calculated
as the arithmetic average of the 6 biggest Protrusion Base
Widths.
[0385] 3) Protrusion Height Test Method
[0386] The topsheet/acquisition layer laminate is extracted from
the absorbent article as described above in the Protrusion Base
Width Test Method.
[0387] The topsheet/acquisition layer laminate specimen comprising
three-dimensional protrusions is then conditioned and scanned under
a pressure of 1.86 kPa (0.27 psi) with the body-facing side upward,
i.e. the topsheet of the topsheet/acquisition layer laminate being
upward as described above in the Protrusion Base Width Test
Method.
[0388] After the image has been captured, the X-Y-Z coordinates of
every pixel of the 40 mm.times.30 mm field of view area are
recorded and smoothed/filtered as described above in the Protrusion
Base Width Test Method. A reference plane is also defined as
described above in the Protrusion Base Width Test Method.
[0389] In the Primos Optical Profiler instrument, to measure the
Material Area of the Reference Plane (Z=-0.1 mm), click on the
button "Evaluate". Then apply a pre-filtering routine including a
polynomial filter (n=6), a median filter 11 by 11 and a structure
filter (n=81) using the function "Filter". Save the image to a
computer file with ".omc" extension.
[0390] The same above procedure set out in the Protrusion Base
Width Test Method is then executed on the topsheet/acquisition
layer laminate with the garment-facing side upward (i.e. the
acquisition layer of the topsheet/acquisition layer laminate being
upward), the 40 mm.times.30 mm field of view being located at the
exact same X-Y position of the topsheet/acquisition layer
laminate.
[0391] The Empty Area of the reference plane can be defined as the
area of the Reference Plane that is above the surface profile. The
Empty Area having boundaries strictly located inside the field of
view area (i.e. 30 mm.times.40 mm) without crossing or overlapping
with the boundaries of the field of view area (i.e. 40 mm.times.30
mm) are defined as Isolated Empty Area(s). The Protrusion Height is
defined for an Isolated Empty Area as the distance between the
minimum Z value of the points of the topsheet/acquisition layer
laminate surface profile having X-Y coordinates located in this
Isolated Empty Area, and the Z value of the top X-Y plane.
[0392] Click on "Draw N parallel lines" and draw a first segment
parallel to the X axis of the field of view (direction of the
longest dimension of the field of view) passing through the center
of the Isolated Empty Area and extending outside the Isolated Empty
Area boundaries. The center of the Isolated Empty Area corresponds
to the middle of the segment parallel to the Y axis of the field of
view and joining the biggest and smallest Y value of the Isolated
Empty Area. Then input the "number" of lines to be drawn and set
the "distance" between lines to 0.05 mm. Enough lines need to be
drawn such to cover the entire Isolated Empty Area. Leave the
averaging parameter to 0 then click "Ok". Then click on "Show
sectional picture". Click on the point of the sectional picture
profile having the minimum Z value and click on "Vertical distance"
to obtain the Protrusion Height.
[0393] For both of the acquired and digitized images, the
Protrusion Height of all the Isolated Empty Areas is determined.
Then, the Measured Protrusion Height is calculated as the
arithmetic average of the 6 biggest Protrusion Heights.
Flat Acquisition Test Method
[0394] This method determines the acquisition times of a baby
diaper. The method settings are depending on the diaper size
tested. Table 1 shows commonly used diaper size descriptions to be
used as reference.
TABLE-US-00002 TABLE 1 commonly used size descriptions for diapers
Size Alternative Size Descriptions 1 newborn 2 S P Infant 3 M
Crawler 4 L G Toddler 5 XL XG Walker 6 XXL XXG Junior
Apparatus
[0395] The test apparatus 1400 is shown in FIG. 17 and comprises a
trough 1411 made of polycarbonate (e.g. Lexan.RTM.) nominally 12.5
mm (0.5 inch) in thickness. The trough 1411 comprises a rectilinear
horizontal base 1412 having a length of 508 mm (20.0 inches), and a
width of 152 mm (6.0 inches). Two rectilinear vertical sides 1413,
64 mm (2.5 inches) tall.times.508 mm (20 inches) in length are
affixed to the long edges of the base 1412 to form a U-shaped
trough 1411 having a length of 508 mm (20.0 inches), an internal
width of 152 mm (6.0 inches), and an internal depth of 51 mm (2.0
inches). The front and back ends of the trough 1411 are not
enclosed.
[0396] A slab of open-cell polyurethane foam 1414 with dimensions
508.times.152.times.25 mm is wrapped in polyethylene film and
placed in the bottom of the trough 1411 in such a way that the
edges of the foam 1414 and the trough 1411 are aligned, and the
upper surface of the polyethylene film is smooth and free of seams,
wrinkles or imperfections. The polyurethane foam 1414 has a
compression hardness at 40% compression CV.sub.40 of 2.4 kPa+/-0.4
kPa as determined according to DIN EN ISO 3386 and a density of 16
kg/m.sup.3+/-2 kg/m.sup.3 as determined according to DIN EN ISO
845, e.g. a film wrapped foam can be purchased from Crossroads
Machine Inc., Englewood Ohio 45322, USA under the description of
"FOAM BASE FOR LIQUID ACQUISITION TEST", or equivalent film-wrapped
foam may be used. A reference line is drawn across the width of the
upper surface of the polyethylene cover 121 mm (6.0 inches) from
one end (the front edge) parallel to the transverse centerline
using an indelible marker: such reference line distance must be
adjusted according to size based on the table 1.
[0397] A rectilinear polycarbonate top plate 1415 has a nominal
thickness of 12.5 mm (0.5 inch), a length of 508 mm (20.0 inches),
and a width of 146 mm (5.75 inches). A 51 mm (2.0 inch) diameter
hole is bored in the center of the top plate 1415 (i.e. the center
of the hole is located at the intersection of the longitudinal and
transverse axes of the upper surface of the top plate 1415). A
polycarbonate cylinder 1416 with an outside diameter of 51 mm (2.0
inches), an internal diameter of 37.5 mm (1.5 inches) and a height
of 102 mm (4.0 inches) is glued into the hole in the top plate 1415
so that the bottom edge of the cylinder 1416 is flush with the
lower surface of the top plate 1415 and the cylinder 1416 protrudes
vertically 89 mm (3.5 inches) above the upper surface of the top
plate 1415, and the seam between the cylinder 1416 and the top
plate 1415 is watertight. An annular recess 1417 with a height of 2
mm (0.08 inch) and a diameter of 44.5 mm (1.75 inches) is machined
into the bottom internal edge of the cylinder 1416. A nylon wire
mesh (the opening of this nylon mesh is 1.5 mm, the nylon wire
diameter is 0.5 mm) is glued into the recess 1417. The mesh is
prepared via cutting a circle of 44.5 mm diameter and cutting of 5
mm of the diameter at each opposite side (i.e. 180.degree. apart).
Two 1 mm diameter holes are drilled at a 45.degree. angle to the
upper surface of the top plate 1415 so that the holes intersect the
inner surface of the cylinder 1416 immediately above the recess
1417 and are at opposite sides of the cylinder 1416 (i.e.
180.degree. apart). Two stainless steel wires 1418 having a
diameter of 1 mm are glued into the holes in a watertight fashion
so that one end of each wire is flush with the inner cylinder wall
and the other end protrudes from the upper surface of the top plate
1415. These wires are referred to as electrodes herein below. A
reference line is scribed across the width of the top plate 1415 at
a specific distance from the front edge parallel to the transverse
centerline. The distance is size specific and shown in table 2
below. For example 121 mm is the distance for size 4. The top plate
1415/cylinder 1416 assembly has a weight of approximately 1180
grams.
TABLE-US-00003 TABLE 2 Size specific distances, gush volumes and
rates Reference line Gush Gush Size distance [mm] volume [ml] rate
[ml/s] 1 160 24 8 2 147 40 8 3 134 50 10 4 121 75 15 5 121 75 15 6
121 75 15
[0398] Two steel weights each weighing 4.5 Kg and measuring 146 mm
(5.75 inches) wide, 38 mm (1.5 inches) deep, and approximately 100
mm (4 inches tall) are also required.
Procedure
[0399] All testing is carried out at 23.+-.2.degree. C. and
50.+-.10% relative humidity.
[0400] The polycarbonate trough 1411 containing the wrapped foam
slab 1414 is placed on a suitable flat horizontal surface. A
disposable absorbent product is removed from its packaging and the
cuff elastics are cut at suitable intervals to allow the product to
lay flat. The product is weighed to within .+-.0.1 grams on a
suitable top-loading balance then placed on the covered foam slab
1414 in the acquisition apparatus with the front waist edge of the
product aligned with the reference mark on the polyethylene cover.
The product is centered along the longitudinal centerline of the
apparatus with the topsheet (body-side) of the product facing
upwards and the rear waist edge toward the rear end of the foam
slab 1414. The top plate 1415 is placed on top of the product with
the protruding cylinder facing upwards. The scribed reference line
is aligned with the front waist edge of the product and the rear
end of the top plate 1415 is aligned with the rear edge of the foam
slab 1414. The two 4.5 Kg weights are then gently placed onto the
top plate 1415 so that the width of each weight is parallel to the
transverse centerline of the top plate, and each weight is 83 mm
(3.25 inches) from the front or rear edge of the top plate 1415.
The point of the topsheet of the product falling at the center of
the cylinder is marked as loading point of the article.
[0401] A suitable electrical circuit is connected to the two
electrodes to detect the presence of an electrically conductive
fluid between them.
[0402] A suitable pump; e.g. Model 7520-00 supplied by Cole Parmer
Instruments, Chicago, USA, or equivalent; is set up to discharge a
0.9 mass % aqueous solution of sodium chloride through a flexible
plastic tube having an internal diameter of 4.8 mm ( 3/16 inch),
e.g. Tygon.RTM. R-3603 or equivalent. The end portion of the tube
is clamped vertically so that it is centered within the cylinder
1416 attached to the top plate 1415 with the discharge end of the
tube facing downwards and located 50 mm (2 inches) below the upper
edge of the cylinder 1416. The pump is operated via a timer and is
pre-calibrated to discharge a gush of 75.0 ml of the 0.9% saline
solution at a rate of 15 ml/sec (for size 4 or equivalent). The
volume and rate to be used for specific sizes is illustrated in the
table 1 above.
[0403] In the following the case of size 4 is exemplified: for
other sizes the only difference will be to replace the reference
line distance, gush volume and gush rate for the specific size as
defined in the table 1. The pump is activated and a timer started
immediately upon activation. The pump delivers 75 mL of 0.9% NaCl
solution to the cylinder 1416 at a rate of 15 ml/sec, then stops.
As test fluid is introduced to the cylinder 1416, it typically
builds up on top of the absorbent structure to some extent. This
fluid completes an electrical circuit between the two electrodes in
the cylinder. After the gush has been delivered, the meniscus of
the solution drops as the fluid is absorbed into the structure.
When the electrical circuit is broken due to the absence of free
fluid between the electrodes in the cylinder, the time is
noted.
[0404] The acquisition time for a particular gush is the time
interval between activation of the pump for that gush, and the
point at which the electrical circuit is broken.
[0405] Four gushes are delivered to the product in this fashion;
each gush is 75 ml and is delivered at 15 ml/sec. The time interval
between the end of a certain gush, i.e. when the electrical circuit
is broken after the liquid acquisition, and the beginning of the
next gush is 300 seconds.
[0406] The acquisition time for four gushes is recorded to the
nearest 1.0 s. Eight products for each option are tested in this
fashion and the average gush time for each of the respective gushes
(first through fourth) is calculated.
[0407] A new foam base 1414 is taken for each test or let the foam
base relax for at least 24 hours before re-using it.
[0408] The total acquisition time is the sum of the acquisition
time of gush 1, the acquisition time of gush 2, the acquisition
time of gush 3 and the acquisition time of gush 4. The total
acquisition time is expressed in seconds.
Liquid in Topsheet Test Method
Objective
[0409] The Liquid in topsheet Test Method is the determination of
the retained liquid in the topsheet, i.e. a measure of the topsheet
dryness. In order to determine the amount of residual fluid in the
topsheet, i.e. the liquid in topsheet, it is aimed at measuring the
wet topsheet sample weight, i.e. after removing from the diaper
test sample and separating from the acquisition layer, and dry the
topsheet sample weight after at least 16 hours in an oven at
60.degree. C.
Experiment Setup
[0410] Mark the loading point of the diaper as it has been
described in the Flat acquisition method as set out above. [0411]
Take the diaper out of the Flat Acquisition Test Method apparatus.
[0412] On the diaper, when the topsheet is facing the operator,
mark using a permanent ink pen and a plexiglass template (55 mm
wide in cross direction, 120 mm long in machine direction, 1-5 mm
thick) a rectangle onto the topsheet, symmetrically (centered in
cross direction and machine direction) around the loading point.
[0413] Perform the Flat acquisition test method as described above.
[0414] At least 10 minutes, but not more than 11 minutes after the
last gush of the above acquisition test is absorbed, remove the
cover plate and weights, and [0415] Place carefully the diaper test
sample flat on a lab bench.
Preparation of the Wet Topsheet Sample and Determination of the
Liquid in Topsheet
[0416] The topsheet/acquisition layer laminate is then cut with a
scalpel along the marked rectangle.
[0417] The wet topsheet of the topsheet/acquisition layer laminate
is carefully separated from the acquisition layer underneath while
touching it only with tweezers and as little as possible: if
necessary freeze off spray can be used to remove more easily the
topsheet without tearing it. The wet topsheet sample has dimensions
of 55 mm wide and 120 mm long.
[0418] The wet topsheet sample is put in a tarred Petri dish.
[0419] Then, the wet topsheet sample is weighed to the nearest
0.001 g, which provides the wet topsheet sample weight.
[0420] The wet topsheet sample, contained in its Petri dish, is
placed for at least 16 hours into an oven at 60.degree. C.
[0421] Then, the Petri dish with the topsheet sample is taken out
of the oven; let it cool down to the controlled environment of the
test room for at least 10 minutes.
[0422] The dry topsheet sample is placed on a new tarred Petri
dish. The weight of the dry topsheet sample is recorded from a
balance to the nearest 0.001 g.
[0423] The liquid in topsheet is then calculated as the difference
between the wet topsheet sample and dry topsheet sample
weights.
[0424] Four samples for each type of absorbent article are tested
according to this procedure and the average liquid in topsheet is
calculated.
[0425] The Topsheet Load is calculated as the ratio of the liquid
in topsheet with the weight of the dry topsheet. Four samples for
each type of absorbent article are tested according to this
procedure and the average Topsheet Load is calculated.
Post Acquisition Collagen Rewet Test Method
[0426] This method requires a collagen film having a Fixed Height
Frit Absorption (FHFA-0cm) between 0.48 g/g and 0.66 g/g and
FHFA-20 cm between 0.15 g/g and 0.21 g/g as measured according to
the method described below. The collagen film has also a basis
weight of 31.5+/-3.5 g/m.sup.2. The collagen film can be purchased
from Viscofan Group, 31192 Tajonar-Navarra, Spain, under the
designation of Naturin COFFI clear, or equivalent material having
the characteristics and basis weight as described above.
[0427] Before executing the test, the collagen film as is prepared
by being cut into circular sheets of 90 mm (3.54 inches) diameter
e.g. by using a sample cutter device, and by equilibrating the film
in the controlled environment of the test room (see Flat
Acquisition Test Method) for at least 12 hours (tweezers are to be
used for all handling of the collagen film).
[0428] At least 5 minutes, but not more than 6 minutes after the
last gush, which has been performed in the above Flat Acquisition
Test Method, is absorbed, the cover plate and weights are removed,
and the test sample is carefully placed flat on a lab bench.
[0429] Four sheets of the precut and equilibrated collagen material
(510) are weighed with at least one milligram accuracy, and then
positioned centered onto the loading point of the article, as
defined in the Flat Acquisition Test Method, and covered by a plate
(530) made of Poly(methyl methacrylate) (PMMA) (e.g. Perspex.RTM.)
of 90 mm (3.54 inches) diameter, and about 20 mm (0.78 inches)
thickness. A weight (550) of 15 kg is carefully added (also
centered). After 30+/-2 seconds the weight and Perspex.RTM. plate
are carefully removed again, and the collagen films are reweighed
(See the system 500 in FIG. 18).
[0430] The Rewet result is the moisture pick up of the collagen
film, expressed in mg. Four products for each option are tested in
this fashion and the average rewet is calculated.
Fixed Height Frit Absorption (FHFA) at 20 cm and at 0 cm Test
Methods
[0431] This test is suitable of measuring the uptake of a material
under the conditions of suction pressures of 20 cm or of 0 cm of
fluid, for example of a saline solution (0.9% wt. NaCl solution)
after 30 s.
General Apparatus Setup:
[0432] FIG. 19 shows the FHFA measurements setup 400: a suitable
fluid delivery reservoir 421, has an air tight stopcock 424 to
allow the air release during the filling of the equipment. An
open-ended glass tube 422 having an inner diameter of 10 mm extends
through a port 425 in the top of the reservoir such that there is
an airtight seal between the outside of the tube and the reservoir,
this allows maintaining the required zero level of the hydro head
during the experiment regardless the amount of liquid in the
reservoir. Reservoir 421 is provided with delivery tube 431 having
an inlet at the bottom of the reservoir, a stopcock 423, with the
outlet connected to the bottom 432 of the sample holder funnel 427
via flexible plastic tubing 426 (e.g. Tygon.RTM.). The Fluid
reservoir is firmly held in position by means of standard lab
clamps 413 and a suitable lab support 412. The internal diameter of
the delivery tube 431, stopcock 423, and flexible plastic tubing
426 enables fluid delivery to the sample holder funnel 427 at a
high enough flow rate such that such flowrate is higher than the
flowrate absorbed by the collagen sample in the conditions of the
experiment and exclude that the measured uptake is limited by the
fluid flowrate supplied by the equipment system. The reservoir 421
has a capacity of approximately 1 liter. Other fluid delivery
systems may be employed provided that they are able to deliver the
fluid to the sample holder funnel 427 maintaining the zero level of
the hydrostatic liquid pressure 403 at a constant height during the
whole experiment.
[0433] The sample holder funnel 427 has a bottom connector with an
internal diameter of 10 mm, a measurement and a chamber 433 where a
glass frit 428 is accommodated. The sample holder chamber has a
suitable size to accommodate the sample 430 and the confining
pressure weight 429. The frit is sealed to the wall of the chamber
433. The glass frit has pore of specific size of 16-40 .mu.m (glass
frit type P 40, as defined by ISO 4793) and a thickness of 7
mm.
[0434] The confining pressure weight 429 is a cylinder with a
diameter identical to the sample size (6 cm) and a weight of 593.94
g so to apply exactly 2.06 kPa of confining pressure to the sample
430. The sample holder funnel 427 is precisely held in position
using a suitable lab support 411 through a standard lab clamp 414.
The clamp should allow an easy vertical positioning of the sample
holder funnel 427 such that the top of the glass frit 428 can be
positioned at a) the same height (+/-1 mm) of the bottom end 404 of
the open ended glass tube 422 and b) exactly 20 cm (+/-1 mm) above
the bottom end 404 of the open ended glass tube 422. Alternatively
two separated clamps are positioned at the abovementioned setups a
and b and the sample holder funnel is alternatively moved from one
to the other. During the non-usage time, the instrument is kept in
proper operating conditions flooding the sample holder funnel 427
with an excess of liquid to guarantee a proper wetting of the glass
frit 428 that should be completely below the liquid level. The
sample holder funnel 427 is also covered with an air tight cap (not
shown) to avoid evaporation and therefore a change in solution
salinity. During storage stopcocks 423 and 424 are also accordingly
closed to avoid evaporation as well as the open ended tube 422 air
tight sealed with a cap (not shown).
Sample Preparation
[0435] During the sample preparation, the sample is only touched
with the tweezers. Discs of 6 cm diameter are cut out of the
collagen material using any suitable die cutter. The samples are
then stored in a closed container, e.g. a petri dish with lid, and
conditioned in the controlled environment of the test room for at
least 24 hours.
Material Used:
[0436] Saline solution at a concentration of 0.9% by weight
[0437] FHFA equipment (as set out above)
[0438] Bubble level
[0439] Analytical balance with a resolution of .+-.0.001 g with air
draft protections.
[0440] Funnel
[0441] Tweezers
[0442] Timer
Experiment Setup
[0443] Before starting the experiment: [0444] 1) The caps to the
open ended tube 422 and the sample holder funnel 427 are removed.
[0445] 2) Ensuring the stopcock 423 is closed, the stopcock 424 is
opened to allow the air to flow out of the liquid reservoir as
displaced by liquid during the refilling phase. The liquid
reservoir 421 is refilled through top end of the open-end tube 422
with the 0.9% Saline solution with the help of suitable means such
a funnel (not shown) at the end of the filling the stopcock 424 is
closed. [0446] If during all the experiments the liquid level would
be close to the bottom 404 of the open-ended tube 422, before
running the next sample, the liquid reservoir must be refilled
repeating this step number 2. [0447] 3) The sample holder funnel
427 is removed from the lab clamp 414 and the excess of liquid is
removed pouring it away. [0448] 4) Manually holding the sample
holder funnel 427 such that the top of the glass frit 428 lies
around 20 cm below the bottom end 404 of the open-ended tube 422
the stop cock 423 is carefully open until the air liquid interface
in the open ended tube 422 reaches the bottom end 404 and a few
bubble of air escape from tube 422. At this point the stop cock 423
is closed. [0449] 5) The excess of liquid now present in the sample
holder funnel 427 is again disposed and the system is now ready to
start the measurements.
For Measuring the Fixed Height Frit Absorption (FHFA) at 20 cm, for
Each Replicate:
[0449] [0450] 1) The sample holder is positioned on the clamp 414
such that the top of the glass frit 428 lies exactly 20 cm (+/-1
mm) above the bottom end 404 of the open-ended tube 422. To ensure
a reliable measure it is checked that the glass frit 428 is
perfectly horizontal with the help of a bubble level. [0451] 2) Any
remaining droplets of liquid on top of the glass frit are carefully
removed by means of a filter paper of any other suitable material.
[0452] 3) The sample is weighed with an analytical balance with a
resolution of .+-.0.001 g. The Weight is recorded as Dry Sample
Weight (W.sub.D) to the nearest 0.001 g when the readings on the
balance become constant. [0453] 4) 4 sheets of collagen material
are carefully aligned on top of each other using tweezers. This
stack of 4 sheets of collagen is subsequently referred to as
"sample". The sample 430 is positioned in the center of the sample
holder with the help of tweezers with particular care in not
altering the orientation and relative position of each of the
layers of the acquisition system. [0454] 5) The confining weight
429 is positioned centered on the sample [0455] 6) The stopcock 423
is opened for 30+/-1 seconds allowing liquid to flow in the sample
and then closed again. [0456] 7) The confining weight 429 and the
sample 430 are carefully removed from the glass frit 428 with the
help of tweezers. [0457] 8) The sample 430 is weighed with the
analytical balance with a resolution of .+-.0.001 g. The Weight is
recorded as 20 cm Sample Weight (W.sub.20) to the nearest 0.001 g
when the readings on the balance become constant.
[0458] The measurements of a sample are now completed and a
subsequent replicate can be measured repeating the above steps.
Once terminated the series of experiment around 1 cm of liquid is
added on the Sample Holder funnel 427 to completely submerge the
glass frit 428. All the stopcocks are closed and the cap positioned
according to the storage condition explained above to avoid
evaporation and ensure reliability of the subsequent
measurements.
Calculations:
[0459] The FHFA at 20 cm (FHFA.sub.20) is defined according to the
following formula:
FHFA.sub.20=(W.sub.20-W.sub.D)/W.sub.D and has unit of g/g.
For Measuring the Fixed Height Frit Absorption (FHFA) at 0 cm, for
Each Replicate:
[0460] 1) The sample holder is positioned on the clamp 414 such
that the top of the glass frit 428 lies exactly 0 cm (+/-1 mm)
above the bottom end 404 of the open-ended tube 422. To ensure a
reliable measure it is checked that the glass frit 428 is perfectly
horizontal with the help of a bubble level. [0461] 2) Any remaining
droplet of liquid on top of the glass frit are carefully removed by
means of a filter paper of any other suitable material. [0462] 3)
The sample is weighed with an analytical balance with a resolution
of .+-.0.001 g. The Weight is recorded as Dry Sample Weight
(W.sub.D) to the nearest 0.001 g when the readings on the balance
become constant. [0463] 4) 4 sheets of collagen material are
carefully aligned on top of each other using tweezers. This stack
of 4 sheets of collagen is subsequently referred to as "sample".
The sample 430 is positioned in the center of the sample holder
with the help of tweezers with particular care in not altering the
orientation and relative position of each of the layers of the
acquisition system. It is important that the topsheet facing side
of each layer is facing now downwards during the experiment in the
direction of the glass frit 428, reproducing the liquid flow
entrance direction correctly. [0464] 5) The confining weight 429 is
positioned centered on the sample [0465] 6) The stopcock 423 is
opened for 30+/-1 seconds allowing liquid to flow in the sample and
then closed again. [0466] 7) The confining weight 429 and the
sample 430 are carefully removed from the glass frit 428 with the
help of tweezers. [0467] 8) The sample 430 is weighed with the
analytical balance with a resolution of .+-.0.001 g. The Weight is
recorded as 0 cm Sample Weight (W.sub.0) to the nearest 0.001 g
when the readings on the balance become constant.
[0468] The measurements of a sample are now completed and a
subsequent replicate can be measured repeating the above steps.
Once terminated the series of experiment around 1 cm of liquid is
added on the Sample Holder funnel 427 to completely submerge the
glass frit 428. All the stopcocks are closed and the cap positioned
according to the storage condition explained above to avoid
evaporation and ensure reliability of the subsequent
measurements.
Calculations:
[0469] The FHFA at 0 cm (FHFA.sub.0) is defined according to the
following formula:
FHFA.sub.0=(W.sub.0-W.sub.D)/W.sub.D and has unit of g/g.
[0470] 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."
[0471] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0472] 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 is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *