ABSORBENT ARTICLES WITH AN IMPROVED VENTILATION

ARTICLES ABSORBANTS AVEC DEBIT DE GAZ TRAVERSANT PAR CONVECTION ACCRU

English Abstract

Absorbent article allowing for convective gas/air transport therethrough, especially by providing absorbent cores, which have sufficient basis capacity and air/gas permeability at the same time. The absorbent core comprises a liquid storage region, and a liquid acquisition/distribution region positioned between the liquid storage region and the topsheets said acquisition/distribution region comprises an evaporation barrier layer/region.

French Abstract

Ci-après un article absorbant permettant le transport de gaz/air par convection au travers dudit article, en particulier en fournissant des noyaux absorbants possédant une capacité de base et une perméabilité au gaz/air (en même temps) suffisantes. Le noyau absorbant comprend une région de stockage de liquide, et une région d'acquisition/distribution de liquide positionnée entre la région de stockage de liquide et la coiffe, la région d'acquisition/distribution comprend une couche/région de barrière d'évaporation.

Claims

39

Claims:

1. Absorbent article, comprising:
a top sheet;
a backsheet comprising an aperture formed film; and
an absorbent core, the absorbent core comprising a superabsorbent arranged in
a homogeneous blend with fluff pulp or layered between open and permeable
layers of
porous materials,
wherein said core provides a basis capacity of at least 0.7 ml/cm2,
and wherein said backsheet provides a Dynamic liquid impact performance of
less than 20 g/m2 and a polyhole rewet of less than 0.10 mg.
2. Absorbent article according to claim 1, wherein said absorbent core has
a design
capacity and wherein the absorbent core has an ultimate storage capacity of
less than 2
times the design capacity of the absorbent core.
3. Absorbent article according to any one of claims 1 to 2, wherein said
backsheet
provides a polyhole rewet of less than 0.05 mg.
4. Use of absorbent article according to any one of claims 1 to 3 on a
wearer,
thereby defining a space between the article and the wearer, said space
exhibiting an
micro climate having a Relative Humidity of less than 50% RH.

Description

CA 02672562 2009-07-27
ABSORBENT ARTICLES WITH AN IMPROVED VENTILATION
10
The present invention relates to disposable absorbent articles, such as baby
diapers,
adult Incontinence articles, and in particular to such articles providing
improved aeration
during use.
Background
Disposable, absorbent articles such as diapers, incontinence articles,
sanitary towels,
training pants and the like are well known in the art Typically, disposable
absorbent
articles comprise a liquid pervious topsheet that faces the wearer's body, a
liquid
Impervious backsheet that faces the wearer's. clothing, an absorbent core
interposed
between the liquid previous topsheet and the backsheet, and means to keep the
core in
fixed relation tithe wearer's body.
Numerous attempts have been disclosed aiming at improving on the skin
condition of the
wearer by allowing the over-hydrated skin to dehydrate to an acceptable level
by allowing
either air to reach the skin thus minimizing potential occlusion effects,
and/or by water
vapor being removed from the surface of the skin. Generally, such mechanisms
are
referred to as ¶breathability or "vapor or moisture permeability*.
A number of such applications aim at feminine hygiene products, such as
catamenial
products or so-called 'panty-liner as described in EP-A-0.104.906; EP-A-
0.171.041; EP-
A-0.710.471. W097/23182 further discloses an absorbent structure comprising
fibrous
superabsorbent material, combining such breathable materials with fibrous

CA 02672562 2010-12-29
2
superabsorbent material in the absorbent core. Such products generally have
relatively
low fluid storage capacity when compared for example to baby diapers or adult
Incontinence products, often being designed for theoretical capacities
significantly
exceeding the ones for the feminine hygiene products.
Such breathable materials can be various kinds of webs, such as films which
were
rendered air and/or vapor permeable by aperturing as described In US-A-
5.628.737, or
by exploiting the 6miaoporosity property as described in EP-A-0.238.200; EP-A-

0.288.021; EP-A-0.352.802; EP-A-0.515.501; US-A-4.713.068, whereby small voids
are
created within the film similar to very small cracks. WO 94/23107; WO
94/28224; US-A-
4.758.239; EP-A-0.315.013 all describe alternative breathable materials which
can be
fibrous textile or non-woven webs, with air or vapor easily penetrating
through the
relatively large pores of the structure. Such webs can be either untreated or
treated with
regard to improving their liquid Impermeability properties, such as described
in EP-A-
0.198.654. In WO 95/16562 a laminate of a non-woven with a breathable film is
disclosed. Further disclosures such as in WO 95/16746 relate to other
materials allowing
water molecules to diffuse through. Also, combinations of various materials
comprising
various layers any of the above elements are also well known.
In particular for articles designed for receiving higher amounts of liquids,
such as baby or
adult incontinence diapers, other approaches aimed at keeping only part of the
article
breathable, such as by covering the liquid absorbing parts (often referred to
as absorbent
core) by a non-breathable material, but having other parts of the article made
of
breathable materials, see e.g. EP-A-0.059.503 (Obenour).
There have been many attempts to Improve the fluid handling properties of
absorbent
articles or cores, In particular when further requirements were brought up
such as a
desired reduction of product bulkiness or thickness. Such effects are
discussed In
European Patent Application EP0797968 filed on March 29, 1996, but also in US-
A- =
4.898.842; EP-A-0.840.330; EP-A-0.397.110; EP-A-0.312.118.
PCT publication WO 98158609 discloses a disposable absorbent article
sustaining low
vapor phase moisture in the space as enclosed between the article and the
wearer in
use, such as can be evaluated by measuring relative humidity on a laboratory

CA 02672562 2009-07-27
3
mannequin, such as can be achieved by combining high performance, low rewet
absorbent cores with very breathable badcsheet materials. Thus, the thrust of
this
disclosure aims at providing absorbent article with good liquid retention in
the cores,
combined with water vapor permeable, liquid Impermeable barrier materials such
as for
the use as badcsheets. The preferred, specific embodiment of this disclosure
directs
towards the use of a high amount of absorbent capacity so as to dry out the
structures
close to the skin of a wearer.
A series of related and co-filed PCT applications (WO 00/10497; WO 00/10498,
WO
00/104099, WO 00/10500, WO 00110501) relates to breathable absorbent articles,

including when these are in the wet state. One approach described therein
relates to
creation of high permeability zones within an absorbent core, such as by
aperturing the
absorbent core, or by creating portions in the core containing substantially
less high
absorbency material than other portions of the core. Overall, the gas transfer
mechanisms rely on gas diffusion mechanism, such as demonstrated by the
preferred
use of microporous film materials, as well as by the Tracer Gas Test The
approaches
described therein can lead to relatively good relative humidity conditions
while being
worn, as long as the article is not loaded such as with urine, but will
exhibit significantly
increased relative humidity conditions upon loading.
Thus the prior art failed to provide satisfactory solutions for absorbent
cores, wherein the
ultimate storage capacity is not too much exceeding the design capacity, i.e.
the capacity
required to absorb the expected loading during the intended use. Thus, the
ultimate
storage capacity should preferably not be more than about twice the design
capacity of
the article.
The prior art also failed to provide structures which provide good convective
transport
without unduly complicating the manufacturing process, such as is the case for
strongly
inhornogeneous structure, such as absorbent cores with apertures or
ventilation
openings
Consequently, there is still a need for absorbent articles, wherein the micro
climate and
especially the relative humidity is kept within the ranges as generally
accepted as being

CA 02672562 2009-07-27
4
comfortable, namely between 30 % to 50 %. There is further the need to provide
articles,
wherein the relative humidity Is kept within this range even upon wetting of
the article. '
There is further still the need to achieve such goals without unduly
complicating the
structure, Le. by avoiding designs using high amounts of absorbent, and/or by
creating
strongly inhomogeneous structures, such as cores comprising apertures.
There is further still a need for absorbent articles, wherein good
microcilmate conditions
are achieved by carefully designing the chassis elements.
Summary
The present invention provides an absorbent article with improved performance
such as
by providing articles with good "Wet Article - Relative Humidity differentiar
as being
descriptive for the climate differences between the environment and the space
between
the article and the wearer. Preferably, the article comprises a backsheet
which is air or
gas permeable, but under normal use conditions not liquid permeable. The
absorbent
core can have a ultimate liquid storage capacity which is preferably not
excessive when
compared to the design capacity of the article, though it preferably exhibits
a basis
capacity of more than about 0.7 mi/cm2. The core should further - especially
when being
loaded and wetted allow convective gas or air transport therethrough, such as
by
exhibiting a permeance of at least 0.1 Darcy/mm, preferably of more than 1.0
Darcy/mm
In a particular design, the absorbent core can comprise a liquid storage
region and a
liquid acquisition / distribution region positioned between this liquid
storage region and
said topsheet, whereby this acquisition / distribution region comprises an
evaporation
barrier layer / region, so as to reduce the evaporation tendency of the
article from the
core towards the space between the article and the wearer during the intended
use. The
acquisition / distribution region may contain material having a drip capacity
of at least 5
gig, which can comprise cellulosic fibrous material.
The article may comprise a bellows which is repeatedly deformable to force
airflow
through the absorbent article in a controlled manner.
The articles according to the present invention are particularly suitable for
being used as
hygienic disposable absorbent article, such as a baby diaper, an adult
Incontinence

CA 02672562 2009-07-27
garment, thereby providing a comfortable microdimate in the space between the
article
and the wearer.
Short description of the drawings
5 Fig. 1 - schematic diagram of the Dynamic impact test method;
Fig. 2- schematic diagram of the Water Vapor Transmission method equipment;
Fig. 3- schematic drawing of the harness;
Fig. 4- harness on a mannequin;
Fig. 5- picture of the sensor box equipped with relative humidity sensor;
Fig. 8- acquisition test set up
Fig. 7- post acquisition collagen rewet test set up.
Detailed description
General definitions
As used herein, the term "absorbent articles" refers to devices which absorb
and contain
body exudates, and, more specifically, refers to devices which are placed
against or In
proximity to the body of the wearer to absorb and contain the various exudates

discharged from the body. As used herein, the term "body fluids" Includes, but
is not
limited to, urine, menses and vaginal discharges, sweat and feces.
The term "disposable" is used herein to describe absorbent articles which are
not
intended to be laundered or otherwise restored or reused as an absorbent
article (i.e.,
they are intended to be discarded after use and, preferably, to be recycled,
composted or
otherwise disposed of in an environmentally compatible manner).
As used herein, the term "Z-dimension" refers to the dimension orthogonal to
the length
and width of the member, core or article. The Z-dimension usually corresponds
to the
thickness of the member, core or article. As used herein, the term "X-Y
dimension" refers
to the plane orthogonal to the thickness of the member, core or article. The X-
Y
dimension usually corresponds to the length and width, respectively, of the
member, core
or article.
As used herein, the term "absorbent core" refers to the component of the
absorbent
article that is primarily responsible for fluid handling properties of the
article, induding

CA 02672562 2009-07-27
6
acquiring, transporting, distributing and storing body fluids. As such, the
absorbent core
typically does not include the topsheet or backsheet of the absorbent article.
As used herein, the term 'absorbent member" refers to the components of the
absorbent
core that typically provide one or more fluid handling functionality, e.g.,
fluid acquisition,
fluid distribution, fluid transportation, fluid storage. The absorbent member
can constitute
the entire absorbent core or only a portion of the absorbent core, i.e., the
absorbent core
can comprise one or more absorbent members. The "storage absorbent member" is
the
absorbent member component(s) of the absorbent core that function primarily to
ultimately store absorbed fluids. As discussed above, the storage absorbent
member
may also distribute fluid as a result of its vertical wicking capability.
As use herein, the term layer" refers to an absorbent member whose primary
dimension
Is X-Y, i.e., along its length and width. It should be understood that the
term layer is not
necessarily limited to single layers or sheets of material. Thus the layer can
comprise
laminates or combinations of several sheets or webs of the requisite type of
materials.
Accordingly, the term layer" includes the terms "layers" and "layered".
For purposes of this invention, It should also be understood that the term
"upper" refers
to absorbent members, such as layers, that are nearest to the wearer of the
absorbent
article during use, and typically face the topsheet of an absorbent article;
conversely, the
term lower" refers to absorbent members that are furthermost away from the
wearer of
the absorbent article and typically face the backsheet.
All percentages, ratios and proportions used herein are calculated by weight
unless
otherwise specified.
Design capacity
In order to be able to compare absorbent articles for varying end use
conditions, or
differently sized articles, the "design capacity" has been found to be a
suitable measure.
For example, babies are representing a typical usage group, but even within
this group
the amount of urine loading, frequency of loading, composition of the urine
will vary
widely from smaller babies (new-born babies) to toddlers on one side, but also
for
example among various indMdual toddlers.

CA 02672562 2009-07-27
7
Another user group may be larger children, still suffering from a certain form
of
incontinence.
Also, incontinent adults can use such articles, again with a wide range of
loading
conditions, generally referred to as light incontinence ranging up to severe
incontinence.
Henceforth, such articles being able to cope with such requirements should
have the
capability of picking up such amounts of urine, which will be referred to for
the further
discussion as "design capacity'.
These amounts of fluids have to be absorbed by materials which can ultimately
store the
bodily fluids, or at least the aqueous parts of these, such that - If any -
only little fluid is
left on the surface of the article towards the wearers skin. The term
"ultimate" refers in
one respect to the situation as in the absorbent article at long wearing
times, In the other
respect to absorbent materials which reach their "ultimate" capacity when
being
equilibrated with their environment This can be in such an absorbent article
under real
in-use conditions after long wearing times, or this also can be in a test
procedure for pure
materials or material composites. If the processes under consideration have
asymptotic
kinetic behavior, one skilled in the art will readily consider "ultimate"
capacities to be
reached when the actual capacity has reached a value sufficiently close to the

asymptotic endpoint, e.g. relative to the equipment measurement accuracy.
As an absorbent article can comprise materials which are primarily designed to
ultimately
store fluids, and other materials which are primarily designed to fulfill
other functions such
as acquisition and/or distribution of the fluid, but may still have a certain
ultimate storage
capability, suitable core materials according to the present invention are
described
without attempting to artificially separate such functions. Nonetheless, the
ultimate
storage capacity can be determined for the total absorbent core, for regions
thereof, for
absorbent structures, or even sub-structures, but also for materials as being
used in any
of the previous.

CA 02672562 2009-07-27
8
In case of applying the present invention to other articles requiring
different end-uses,
one skilled in the art will be able to readily adopt the appropriate design
capacities for
other intended user groups.
In order to determine or evaluate the Ultimate Design Storage Capacity of an
absorbent
article, a number of methods have been proposed.
In the context of the present invention, it is assumed, that the Ultimate
Storage Capacity
of an article is the sum of the ultimate absorbent capacities of the
individual elements or
material. For these individual components, various well established techniques
can be
applied as long as these are applied consistently throughout the comparison.
For
example, the Tea Bag Centrifuge Capacity as developed and well established for

superabsorbent polymers can be used for such materials, but also for others.
Once the capacities for the indMdual materials are known, the total article
capacity can
be calculated by multiplying these values (in ml/g) with the weight of the
material used in
the article.
For materials having a dedicated functionality other than ultimate storage of
fluids - such
as acquisition layers and the like - the ultimate storage capacity can be
neglected, either
as such materials do In fact have only very low capacity values compared to
the
dedicated ultimate fluid storage materials, or as such materials are Intended
to not be
loaded with fluid, and thus should release their fluid to the other ultimate
storage
materials.
With such definitions, for example a so-called 'panty liner product exhibits
very low
Ultimate storage capacities of a few mi or less. Feminine Hygiene pads have
often up to
about 20 ml, light urinary incontinence articles have for example 75 ml or
about 90m1,
medium urinary incontinence articles, or also smaller baby diaper can have
about 165 ml,
and toddler size baby diapers reaching 300 ml or more, and severe adult
incontinence
article having 600 ml or more of ultimate storage capacity.
Teabaa Centrifuge Capacity Test acc test1

CA 02672562 2010-12-29
9
Whilst the TCC test has been developed specifically for superabsorbent
materials, it can readily be applied to other absorbent materials.
The Teabag Centrifuge Capacity test measures the Teabag Centrifuge Capacity
values, which are a measure of the retention of liquids In the absorbent
materials.
The absorbent material is placed within a fleabag", Immersed in a 0.9% by
weight
sodium chloride solution for 20 minutes, and then centrifuged for 3 minutes.
The ratio of
the retained liquid weight to the initial weight of the dry material is the
absorptive capacity
of the absorbent material.
Two liters of 0.9% by weight sodium chloride in distilled water is poured into
a tray
having dimensions 24 cm x 30 cm x 5 cm. The liquid filling height should be
about 3 cm.
The teabag pouch has dimensions 6.5 cm x 6.5 cm and Is available from
Teekanne in Dasseidorf, Germany. The pouch Is heat sealable with a standard
kitchen
plastic bag sealing device (e.g. VACUPACK2 PtUilrom Krups, Germany).
The teabag Is opened by carefully cutting it partially, and Is then weighed.
About
0.200g of the sample of the absorbent material, accurately weighed to +1-
0.005g, is
placed in the teabag. The teabag is then closed with a heat sealer. This is
called the
sample teabag. An empty teabag is sealed and used as a blank.
The sample teabag and the blank teabag are then laid on the surface of the
saline
solution, and submerged for about 5 seconds using a spatula to allow complete
wetting
(the teabags will float on the surface of the saline solution but are then
completely
wetted). The timer is started Immediately.
After 20 minutes soaking time the sample teabag and the blank teabag are
removed from
the saline solution, and placed In a Baulaiecht WS136m, Bosch 772 NZKO9ti or
equivalent
centrifuge (230 mm diameter), so that each bag sticks to the outer wall of the
centrifuge
basket The centrifuge lid is closed, the centrifuge is started, and the speed
increased
quickly to 1,400 rpm. Once the centrifuge has been stabilized at 1,400 rpm the
timer is
started. After 3 minutes, the centrifuge is stopped.
The sample teabag and the blank teabag are removed and weighed separately.
The Teabag Centrifuge Capacity (TCC) for the sample of absorbent material is
calculated as follows:
TCC = [(sample teabag weight after centrifuging) - (blank teabag weight after
centrifuging) - (dry absorbent material weight)] 4. (dry absorbent material
weight).

CA 02672562 2009-07-27
Also, specific parts of the structures or the total absorbent articles can be
measured, such as *sect:loner cut outs, Le. looking at parts of the structure
or the total
article, whereby the cutting is done across the full width of the article at
determined points
of the longitudinal axis of the article. In particular, the definition of the
"crotch region" as
5 described above allows to determine the "crotch region capacity". Other
cut-outs can be
used to determine a "basis capacity" (i.e. the amount of capacity contained in
a unit area
of the specific region of the article. Depending on the size of the unit area
(preferably 2
cm by 2 cm) the defines how much averaging is taking place - naturally, the
smaller the
size, the less averaging will occur.
Ultimate Storage Capacity
In order to determine or evaluate the Ultimate Design Storage Capacity of an
absorbent
article, a number of methods have been proposed.
In the context of the present invention, it is assumed, that the Ultimate
Storage Capacity
of an article is the sum of the ultimate absorbent capacities of the
individual elements or
material. For these individual components, various well established techniques
can be
applied as long as these are applied consistently throughout the comparison.
For
example, the Tea Bag Centrifuge Capacity as developed and well established for

superabsorbent polymers (SAP) can be used for such SAP materials, but also for
others.
Once the capacities for the individual materials are known, the total article
capacity can
be calculated by multiplying these values (in ml/g) with the weight of the
material used in
the article.
For materials having a dedicated functionality other than ultimate storage of
fluids - such
as acquisition layers and the like - the ultimate storage capacity can be
neglected, either
as such materials do in fact have only very low capacity values compared to
the
dedicated ultimate fluid storage materials, or as such materials are intended
to not be
loaded with fluid, and thus should release their fluid to the other ultimate
storage
materials.
Basis capacities
Each of the described capacities can also be expressed as a basis capacity,
which is
defined as the respective capacity per a unit area, expressed such as in
mi/crn2 or

CA 02672562 2009-07-27
11
equivalents. This capacity can further be a local basis capacity, or an
average over a
certain area.
Microdimate
The term microcilmate as used herein refers to the conditions of the space
between the
article and the wearer.
In this context, this space is confined by the body of the wearer, generally
the skin of the
wearer, and the hygienic article, comprising the core region of the article,
and the chassis
regions, the latter generally being the peripheral regions. Frequently, the
article
comprises elastication elements, such as leg cuffs, or barrier cuffs. Such
sealing
elements can, but do not need to, reduce the liquid and air exchange between
the
outside or environment and the space between the article and the skin of the
wearer.
Often, this space is a unitary, connected space, but it also can consist of
sub-spaces,
which can be connected to each other or which can be several spaces, which
preferably
all are designed and constructed according to the present invention, as
applicable.
The elements or the materials of the absorbent article are not considered to
be part of
this space, though such elements or materials may extend Into such a space.
Similarly,
body elements are not considered to be inducted in the space. Also, liquid
and/or solid
body exudates, such as urine or feces, are not considered as part of this
space.
Consequently, the space can be described by the conditions of the gas. These
conditions
can have actual, local values (i.e. at one point In time at one location), or
can be
averaged over time or space or both.
The first element of the conditions for the gas space is the composition, and
in particular
the water content, such as expressed as relative humidity, as defined by the
ratio of the
actual water vapor partial pressure to the corresponding water vapor partial
pressure at
saturation. However, other components such as odorous vapors, or skin
attacking
components can be contained in the space.
The temperature in the space is also of importance, as it Is impacting on the
relative
humidity, but also because of its impact on the skin condition, and comfort of
the wearer.

CA 02672562 2009-07-27
12
The temperature can be, but often will not be constant throughout the space.
If the
temperature of the skin of the wearer and the environment are not constant,
there will be
a temperature gradient across the article, across the space and versus the
surface of the
skin of the wearer. =
It has been found, that In order to maintain comfortable and healthy skin, the

microclimate within the space between the article and the wearer should be
kept in the
comfortable relative humidity range, preferably of less than 50% RH, more
preferably of
less than 45% RH and even more preferably less than 40% RH. However, in order
to
prevent underhydration of the skin of the wearer, the microclimate should not
have less
than about 20% RH, preferably not less than about 30%.
Typically, the temperature within the space will be between 30 C and 36 C, and
temperatures of about 34 C are often perceived as comfortable.
In order to achieve such preferred microclimate conditions, it has been found,
that the
article should - when submitted to the In-Vivo microclimate testing - exhibit
a Wet Article
Relative Humidity Differential of less than 20.0%, preferably less than 15.0%,
and even
more preferably less than 10.0%, as defined hereinafter.
A further important aspect of the gas space is the flow of the gas therein, in
particular the
convective transport in the gas phase. This flow is connected with local
pressure
changes in the space - whilst there will generally be no major pressure
differential
between the space and the environment (i.e. the region outside of the article
when worn),
already small changes In pressure, such as can be created by movements of the
wearer,
or a temperature and/or composition differential can cause convective flow
such as
through. gaps between the article, and the wearer. Preferably, it also can
take place
through the article itself, such as through materials of the article. For
articles according to
the present invention, this convection can occur through the article along the
z-direction
of the article, though It may also include x-y directional components.
The convective transport can be measured and expressed by the flow speed or
velocity
(in misec), or by the flow rate (in gisec), or by the area specific flux (in
gisedcm2).

CA 02672562 2011-10-17
13
Convective transport should be distinguished from diffusive transport. The
latter
generally has much lower transport rates, and can - for example - be achieved
by
moisture transport through a barrier layer, such as by using so-called
monolithic films as
can be made from materials as HytrelTM, as available from DuPont, or by slow
migration
of vapor through a microporous film material.
Known elements for allowing convective transport through certain elements of
an article
are very open materials in the non-absorbent (chassis) parts of the article,
such as nets,
or scrims, or non-wovens with a sufficiently high permeability and permeance
for gas (as
discussed hereinafter). Such transport mechanism is also known to through an
absorbent structure, such as when aperturing the core as described in the
above
mentioned series of PCT publications (WO 00/10497; WO 00/10498, WO 00/104099,
WO 00/10500, WO 00/10501), whereby the general teaching of these documents
does
not direct to convective transport through the article, but on diffusive
overall transport -
such as implied by the preferred use of microporous backsheets.
In one aspect, the present invention aims at providing z-directional
convective transport
through the complete absorbent article in the region of where the liquid is
absorbed, i.e.
through the absorbent core, even when this is loaded, and in particular not
through
special "venting means" as disclosed in the prior art but rather through the
absorbent
material itself. Henceforth, in addition to highly permeable backsheet and
topsheet
materials, the article requires an absorbent core, which has a sufficiently
high
permeance in the absorbent material even when being loaded.
In another aspect, the present invention relates to particularly enhanced
convection
through gaps or the article such as described in more detail in U.S. Patent
No. 6,450,997
issued Sept. 17, 2002 entitled ABSORBENT ARTICLE HAVING A BELLOWS FOR
CIRCULATING FRESH AIR (Seitz/Krebs), disclosing enhanced circulation by means
of
bellows pumps.
The particularly useful absorbent structures for the present invention combine
both
functionality of the liquid absorbency with the convective gas transport
through this
structure and the remaining elements forming the absorbent article at the same
time.

CA 02672562 2009-07-27
14
Thus, the ability for convective flow through the structure should not be
created by
inhomogeneities in the structure such as by providing apertures, or particular
regions
with enhanced ability for convective flow at reduced capacity.
The convective transport through dry and or loaded articles can be assessed by
the Gas
Permeability methods, as described herein, whereby permeability values for dry
and wet
articles can be determined. In combination with respective caliper measurement
(on the
dry and/or wet article, respectively), the permeance of the structure can be
calculate, by
dividing the permeability by the thickness of the structure.
For inhomogeneous structures, the sample preparation or the test setup might
require
adaptation so as to not measure through the 'venting channels" such as
apertures and/or
low basis weight, and/or low basis capacity regions.
Preferably, an article according to the present Invention provides for wet
permeance of
more than about 0.1 Darcy/mm, preferably more than about 0.5 Darcy/mm, and
even
more preferably more than about 1.0 Darcy/mm. Typically, the respective dry
article
permeance Is less than the one of the wetted article.
As the core of the article will typically provide an important resistance to
the convective
flow through the article, the core should exhibit a sufficiently high wet
permeance of more
than about 0.1 Darcy/mm, preferably more than about 0.5 Darcy/mm, and even
more
preferably more than about 1.0 Darcy/mm. The respective dry core permeance
should
not be less than the wet one, and Is typically more than 1 Darcy/mm or even
more than
10 Darcy/mm.
Suitable core structures for such articles can be formed according to many
known ways,
and incorporate many known materials, such. as comprising fibrous materials,
such as
cellulose or synthetic fibers, or particulate materials, such as
superabsorbent particles, or
foams, and especially foams formed by the High Internal Phase Emulsion
polymerization
process, or combinations thereof. The combinations can be homogeneous mixtures

thereof, or segregated or separated materials.

CA 02672562 2010-12-29
The openness of such structures can be achieved by selecting particular
arrangements
of permeable materials.
It has been found, that superabsorbent materials are particularly suited to be
used in
5 articles according to the present Invention, If they exhibit high Saline
Flow Conductivity
performance (SFC), preferably of more than 30 = 10'7 are sec/g, when evaluated

according to the disclosure of US-A-5.599.335.
10 Such materials can be arranged In a homogeneous mixing with fluff pulp,
or can be
layered between suitably open and permeable layers of porous materials, such
as
tissues, especially if these are ar-laki, or nonwoven materials.
Particularly suitable materials are superabsorbent materials as described In
the above
15 referenced US-A-5.599.335, when arranged In a homogeneous blend with
conventional
fluff pulp, at a concentration of 50% superabsorbent, preferably 80% and even
more
preferably more than 90% concentration based on the weight of the
superabsorbent/fluff
mixture. Suitable mixtures can further exhibit densities of between 0.1 g/ cm3
and 0.3
cm3, preferably between 0.15 cm3 and 0.2 cm3.
In particular embodiments, such mixtures can comprise means which enhance the
Integrity of the mixture, especially In the dry state. Thus, low amounts of
adhesive may be
added to the mixture, or other binders, such a thermobondable synthetic
fibers.
In addition to the liquid storage elements In the core, the core may comprise
other liquid
handling members, such as for enhancing fluid acquisition, or distribution.
Suitable cores are further described in EP-A-0.774.242; PCT Publications
W099/055263, W099/055264, W099/055265, all tiled on April 23, 1999; PCT
Publication W099/045879 filed on March 18, 1998. The storage core may further
comprise polymeric porous materials, preferably made by the High Internal
Phase
Emulsion Polymerization process ("HIPE" foams), such as described in PCT
Publications W099/0479183 & W099/047091, both filed March 12, 1999.
Optionally,
and often preferred, the storage core can be enveloped by a suitable web, such
as a
paper tissue or a suitable non-woven material, such as described In WO
97/07761 and in

CA 02672562 2010-12-29
18
PCT Publication W099/053877, filed on April 16, 1999.
A further suitable core structure comprises an acquisition/distribution member
which
includes an evaporation barrier, such as an apertured formed film, as
described In more
detail in co-filed PCT application 'Disposable absorbent articles having low
rewet and
reduced evaporation from the core through the topsheer, having publication
No. WO/01/97733.
The absorbent core may further comprise elements, which are particularly
designed to
handle non-urinary excretions, for example feces. At least as long as such
elements are
only loaded with liquid excretions, such as urine, these preferably satisfy
the permeance
requirements as described In the above.
This permeance of the absorbent core should preferably be achieved In the
regions of
the article which at the same time provide absorbent capacity. Whilst It Is
preferred for
material usage efficiency to not have articles with an excessive overall
capacity, the basis
capacity (i.e. the amount of ultimate liquid storage capacity per unit area)
should not be
less than 0.3 mlicrna, preferably not be less than 0.8 mVcm2. This basis
capacity and the
corresponding permeance can be readily determined for structures,' where
sufficiently
homogeneous regions are suffidently large In dimension and size so as to allow
testing.
In situations, where these areas are too small to allow direct measurement
thereof, the
material may be modified so as to allow assessment thereof. For example,
apertures my
be blocked (i.e. filled with inert material, or structures may be rearranged
close large
apertures, (obviously with careful monitoring of the density and the caliper).
Qther artier elements
In addition to the described absorbent core, the absorbent article comprises a
backsheet
to separate the core from the outside of the article. The tenn backsheet
refers to any
material, or layer, or coating, positioned between the core and the
environment in the
direction away from the wearer. Functionally, the backsheet mist on one side
satisfy the
functional requirement of retaining the liquid as deposited onto and into the
article, as
well as being capable of allowing gas or vapor flow rates therethrou0 which
should
preferably be not the rate-limiting step of gas transfer from the inner space
to the outside.

CA 02672562 2010-12-29
17
In addition, the backsheet may satisfy further functions, such as providing
stability and
integrity to the article, or providing a pleasant feel or hand, or masking of
exudates.
Preferably, the backsheet has a WVTR of at least 3000 g/24hrs/m2 , preferably
of more
than 2800 g/24hrs/m2, and even more preferably of more than 4000 g/24hrs/m2
when
submitted to the WVTR test as described hereinafter.
The backsheet should further prevent liquids from soiling the outside
therethrough. and
hence are designed to a leakthrough value of less than 100 g/m2, preferably
less than 50
g/m2, and even more preferably of less than 10 g/m2, when submitted to the
Dynamic
liquid Impact test, and a potyhole rewet performance of less than 0.10 mg,
preferably less
than 0.05 mg, and even more preferably less than 0.01 mg, when submitted to
the
polyhole rewet test, as described hereinafter.
The backsheet material can be a single layer made of homogeneously or
inhomogeneously distributed phases, or a two- or multilayer construction. The
backsheet
material can be a porous material, such as a film with a plurality of
apertures, or it can be
a porous web such as a non-woven or a foam material.
The backsheet thus may be constructed from a variety of materials and or
composites.
For example, the backsheet may be made of polymeric film materials, suitably
apertured
to provide the required breathability without Jeopardizing the leak-through
performance.
The backsheet may be made of non-woven materials, or of multi-layer nonwovens,
such
as well known barrier webs, such as composites comprising a spun-bonded layer
and a
mettblown layer.
Suitable materials are three-dimensionally formed apertured films, preferably
comprising slanted cones, as described in PCT Publications W099/039694 or
W000/039673, both filed on February 3, 1999. Such films may be
combined with non-wovens to form laminates. The backsheets or components
thereof
may be attached to each other or to other elements of the article. For
example, when the
backsheet is a composite made of an apertured film material with a non-woven
web, the .
film material may be attached to the core components. The non-woven can also
be

CA 02672562 2009-07-27
18
attached to the film over the full area of the backsheet, but preferably the
layers are only
attached to each other in the peripheral regions of the article.
Further, the backsheet can be a porous material comprising swellable
substances, such
as superabsorbent materials and the like, as described in PCT publication WO
97/23182.
In yet a further embodiment, the backsheet material or at least parts thereof
are rendered
hydrophobic, such as by applying fiuourocarbon treatments as described in PCT
publication WO 00/14229 (Palumbo).
Exemplary backsheet materials are as follows:
Sample BS-1 is a nonwoven composite made of melt-blown and spunbonded layers
as
provided by BBA -COROVIN, Paine, Germany, under the designation MD3000, and
exhibits at a basis weight of about 12 gsm a WVTR of about 4670 [g/m2/24hr].
When
testing a double layer of this material, the WVTR value is about 4470
[g/m2/24hr].
Sample BS-2 is an apertured formed film with slanted cones, available from
Tredegar
under the designation V174 LD40, exhibiting a WVTR value of about 2850
[g/m2/24hr].
Sample BS-3 is a combination of a layer of sample BS-1 with the film of Sample
BS-2,
providing a WVTR of about 2850 (g/m2/24hr], demonstrating, that the formed
film
resistance to flow dominates.
Further backsheet samples have been submitted to the permeability and caliper
testing
to determine their permeance. As none of the used methods was able to provide
useful
results over the full range of perrneabilities, different methods have been
selected to
provide the data, however, the resulting permeance values as expressed in
Darcy / mm
are comparable across the whole range of selected materials.
Sample BS-4 (RR-1) Is a typical microporous films, e.g. as available from
FinoTech
under the designation BSB-X3-330, then mechanically activated to provide a
MVIR
value of about 1500 [g1m2/24hri. When using the PM, perrneameter, the
permeance was
determined to be 0.0003 Darcy / mm.

CA 02672562 2009-07-27
19
Sample 9S-5 (RR-2) is a further typical microporous film of the same type, but

mechanically activated to then provide a MVTR value of about 3500 (g/m2/24hr].
When
using the PMI permeameter, the permeance was determined to be 0.0005 Darcy /
mm.
Sample BS-8 (MDO) as available from Tredegar Inc. under the designation X25498
or
X25820 and exhibiting a IVIVIR of about 3500 fg/m2/24hri was evaluated
according to the
PM, method, and gave a permeance of 0.0024 Darcy/mm.
=
Sample 88-7 (CDO) as available from EXXON under the designation EXXAIRE and
exhibiting a MVTR of about 3800 [g/m2/24hrj was evaluated according to the PM'

method, and gave a perrneanc:e of 0.0029 Darcy/mm.
Sample 138-1 provided - when submitted to a permeability test by using the
"Textiluhr
nach Kretschmar - a permeance result of about 375 Darcy / mm.
Sample BS-8, being an alternative composite PP-non-woven as available from BBA-

. COROVIN, Peine, Germany, under the designation MD2005, 595513 gave upon
testing
according to the "Textliuhr nach Kretschmar test a permeance of about 125
Darcy /mm.
When submitting sample BS-2 to the aTextiluhr nach Kretschmar testing, It
provided a
result of about 87 Darcy / mm.
Sample 85-9: A further apertured formed film with straight (i.e. non-slanted)
cones, as
available from Tredegar under the designation 515FP, gave upon testing
according to
theliTextiluhr nach Kretschmar test a permeance of about 275 Darcy /mm.
Similarly, the topsheet material must have a sufficient permeability, Sand
should not
impede liquid passage to the absorbent structure.
As can be seen from the above results for backsheets, non-woven materials
generally
exhibit high gas permeance values, and thus conventional materials, such as
described
in EP-A-0.774.242 (Palumbo), lo not
exhibit a
major resistance to gas flow

CA 02672562 2011-10-17
Particularly preferred tospheet materials for applications whereby more or
less solid
excretions can be deposited on the article, are nonwovens comprising
apertures, at least
in the portions thereof, which are aligned with the feces deposition region of
the article,
such as described in more detail in EP-A-0.714.272 or EP-A-0.702.543.
Optionally, and
preferably for feces handling articles, such topsheets can be combined with
feces
handling members e.g. underlying such topsheets, and further described in
these
applications.
The further elements of the article should not limit the convective transport
of the
discussed elements, but - as far as these are in the convective flow path - be
at least as
open as the flow limiting elements. This is particularly relevant for means to
enhance the
integrity of the structure, such as adhesive or other bonding means, or
fixation means
such as tapes and/or landing zone materials, which may be attached to the
outside of
the article. This is also relevant for liquid barriers, such as the leg cuffs
or so called
barrier cuffs. In a particular aspect, when such cuffs are longitudinally
sealed liquid
impermeably to the topsheet, and preferably therethrough, the underlying core
structure
should exhibit the describe permeance requirements at least across the width
of the
article between these tack-down seals of the cuffs.
Beyond not limiting convective flow, further elements can be included, which
increase
the convective flow. For example, bellows can be incorporated into the
article, such as
described in the U.S. Patent No. 6,450,997 issued Sept. 17, 2002, entitled
"ABSORBENT ARTICLE HAVING A BELLOWS FOR CIRCULATING FRESH AIR"
(Seitz/Krebs).
In addition to high permeanc,e values, and to particular basis capacity
requirements,
preferred articles according to the present invention should be comfortably
thin and soft,
and thus should have a caliper of less than 9 mm at their thickest portion,
and a bulk
softness value of less than 10 N, preferably less than 5 N and even more
preferably of
less than 3 N, when tested according to the test method as disclosed in PCT
application,
filed on March 10, 2000, published as WO 01/68022 and titled "Absorbent
Articles
Exhibiting Improved Buckling and Bending Softness".
Methods and determination

CA 02672562 2009-07-27
21
General Conditions and Synthetic Urine
Unless otherwise noted, all tests are carried out at about 22 +/- 2 C and at
35+/-
15% relative humidity. The synthetic urine used in the test methods is 0.9%
solution of
NaCi in distilled water.
Caliber
The caliper of the sample (dry or loaded) is measured (If necessary after a
equilibration
period) under the desired compression pressure for which the experiment will
be run by
using a conventional caliper gauge (such as supplied by AMES, Waltham, MASS,
US)
having a pressure foot diameter of 1 1/8" (about 2.86 cm), exerting a pressure
of 0.2 psi
(about 1.4 kPa) on the sample, unless otherwise desired and notified.
PMI gas permeability
A suitable permeability method for highly permeable materials or structures,
especially
for materials having a certain caliper of thickness, uses a Capillary Flow
Porometer as
supplied by Porous Materials Inc., Ithaca, New York, US. under the designation
CFP -
120 AEXI, with appropriate manuals and software (Version 6.0, CapWin Version
6.54.25;
CapRep Version 6.56.15; CapGraph Version 1.5.1) or equivalent.
When following the operation instructions for determining gas permeability as
outlined in
the user manual, the particular settings have been utilized;
The selected gas is air. The active sample diameter is set to 45 mm. The
cylindrical
sample can be dry or can be wetted. A spacing insert (of 270.82 g) is be
applied without
further compressing the sample. The resulting permeability will be expressed
in Darcy.
Kretschmar Textiluhr
The air permeability is determined by measuring the time in which a standard
volume of
air Is drawn through the test specimen at a constant pressure and temperature.
This test
is particularly suited to materials having relatively high permeability to
gases, such as
nonwovens, apertured films and the like.
The test is operated in a temperature and humidity controlled environment, at
22 2 C
and 35% 15 % relative humidity. The test specimen has to be conditioned for
at least 2
hrs.

CA 02672562 2009-07-27
22
The test equipment as manufactured by Hoppe & Schneider GmbH, Heidelberg,
Germany, under the desigKation 'Textiluhr nadi Kretschmar, is essentially a
bellows in a
vertical arrangement, with its upper end being mounted in a fixed position,
and the lower
end being releasably hold at its upper position, which can be loosened by
means of a
release handle to slide under controlled conditions to the lower position,
thereby
Increasing the volume Inside the bellows by pulling air through the test
specimen which is
covering the air entering opening at the upper end of the bellows. The test
specimen is
firmly hold to cover the air entering opening by means of a fastening ring of
5 cm2 or 10
cm2 to allow for different samples sizes and/or different permeability ranges.
If the 10 cm2
ring is used, the sample should be at least 55 mm wide, for the 5 cm2 ring at
least 35 mm.
For both, the samples should have a length of about 150 mm.
In case of very high permeability materials, the opening can be further
reduced, with
appropriate adjustments to the equipment and calculation.
The equipment comprises a stopwatch (1/100 sec) which automatically measures
the
time between the operation of the release handle thus starting the sliding of
the bellows,
and the bottom of the bellows reaching its lower end position.
The air permeability k of the material can then be calculated as follows:
k= (V*A*d)/(t*A*Ap)
wherein
Via the volume of the bladder, here 1900 ana;
p. is the viscosity of the air, here 1.86104 Pa sec;
d is the test specimen caliper in mm;
t is time required for the expansion of the bellows, in sec;
A is the air entering opening, here 4.155 cm2;
Ap Is the pressure differential, here 160 Pa.
The resulting unit of k is cm* , whereby 1 Darcy corresponds to 9.869* 104
cm2.
The test is repeated once for each test specimen, and should be repeated on 10
specimen to provide a representative basis for a material.
As discussed in the above, the present invention aims at providing permeable
materials
without necessitating the need for creating particular convention channels.
Consequently,

CA 02672562 2009-07-27
23
the above mentioned permeability test (and the respective perraeance
measurement as
described below) should aim at determining the permeability of these
structures, and
henceforth, the above tests may need certain modifications so as to measure
the storage
material rather than the apertures, such as by reducing the test specimen
opening, or- If
readily achievable - by blocking some of the apertures.
Permeance
Permeance Is defined as the permeability (as determined in the above) per unit
thickness
of the material, expressed In Darcy/mm.
Polyhoie test
One piece of 10 cm by 10 cm of Filterpaper such as Grade Medium White W/S
available
from Schleicher & Schutt, Germany is weighed to the nearest 0.001g.
On a suitable flat surface, such as a lab bench, an absorbent article is
Placed fiat over
the fliterpaper, such that the loading point on the topsheet of the article
faces upwards,
and the fliterpaper is centered under this loading point, in direct contact
with the
badmheet of the artide, or the material.to be tested.
The sample is loaded at the loading point for its intended use with an
appropriate volume
of liquid, preferably 0.9% by weight saline solution, generally about 80% of
its theoretical
capacity. If this is not determined, following values can be used,
exemplifying the loading
for various, broadly used baby diaper sizes:
Mini/Mini plus (size 1, 2) 175 ml
Midi (size 3 250 ml
Maxi (size 4) 300 ml
Maxi plus / larger (size 5, 6) 350 ml
The loading of the article is executed by pouring It through a funnel, whereby
the outlet is
positioned 20 mm above the loading point of the absorbent article. A suitable
funnel for
baby diaper applications has funnel diameter of about 82 mm (about 3.1 inch),
a funnel
height of about 132 mm (about 3.5 inch), and an outlet tube of about 70 mm
(about 2.7
inch) length, and about 6.7 mm (about 0.25 inch) inner diameter. The flow rate
of liquid

CA 02672562 2009-07-27
24
into the funnel should be fast, but it should be adjusted by controlled
pouring of liquid so
as to avoid excessive pooling or run-off outside of the article during the
loading.
After addition of the liquid, and a further a waiting period of 60 secs (+/- 3
secs), a
rectangular weight (10 cm* 10 cm; each +/- 3mm) of 3.65 kg +/- 0.5%. After 120
sec (+/-
3 secs), as can be measured by any suitable timer, the weight is removed and
the
fliterpaper is re-weighed to determine the liquid-pick up.
The weight pick up is reported to the nearest 1 mg, and then converted into
and
expressed as fluid absorption in mi.
Dynamic !Auld impact Test
Dynamic fluid transmission is measured with the apparatus 9100 shown in Figure
1.
According to this test, an absorption material 9102 weighed to the nearest
0.0001 gram Is
placed directly on top of the energy absorbing impact pad 9103. The absorption
material
9102 may comprise a No. 2 filter paper available from VVhatman Laboratory
Division,
Distributed by VWR Scientific of Cleveland, OH. The absorption material should
be able
to absorb and retain simulated urine which passes through the sheet material
being
tested. The energy absorbing impact pad 9103 Is a carbon black filled cross
linked
rubber foam. The 12.7 cm by 12.7 cm (5 inch by 5 inch) square impact pad has a
density
of 0.1132 gicrn3 and a thickness of 0.79 cm (0.3125 inches). The impact pad
9103 has a
Durometer Value of N30/15 according to ASTM 2240-91. A circular absorbent core

material 9104 measuring 0.0635 meters (2.5 inches) in diameter is weighed. The

absorbent core material may comprise individualized, crosslinked wood pulp
cellulosic
fibers as described in U.S. Pat. No. 5,137,537 issued to Herron et al. on Aug.
11, 1992.
The absorbent core material should be able to hold a sufficient amount of
simulated urine, e.g., at least about ten times its dry weight
Other absorbent materials that can be used include airfelt, tissue, cellulose
wadding, as long as these exhibit the required absorbent capacity of at least
10 gig. if the
materials have a capacity below 10 gig then they should be wetted to at least
80% of
their saturation capacity. Also, the absorbent materials should be essentially
free of
*superabsorbent materials* which might bind the liquid too tightly and thus
affect the
results.

CA 02672562 2009-07-27
The absorbent core has a basis weight of about 228 g/m2. The absorbent core
material
Is then Is loaded with simulated urine to about ten (10) times its dry weight.
The
simulated urine is an aqueous 0.9 % by weight saline solution, exhibiting a
surface
energy value as conventionally determined of 72.5 Wm.
5 A section of the backsheet material 9105 to be tested Is placed face down
with
the outside surface on a clean and dry tabletop. The loaded core material 9104
is placed
directly In the center of the bacia3heet material 9105. The badtsheet/core
arrangement is
then secured to the Impact portion 9107 of the impact arm 9108 with a rubber
band 9109.
The backsheet/core arrangement is positioned such that the core 9104 is
adjacent the
10 bottom surface 9110 of the impact portion 9107. The impact arm 9108 Is
raised to a
desired broad angle to provide the desired impact energy. The impact arm 9108
is
dropped and the impact arm 9108 is then allowed to rest on the sample for
about two
minutes after impact. The arm is then raised and the filter paper 9102 is
removed and
placed on a digital scale. The mass of the wet filter paper is then recorded
at the three
15 minute mark. The dynamic fluid transmission value (DFTV) is calculated
and expressed
in g/ cm2 using the following formula:
DFTV = {mass of the wet filter paper (grams) - mass of the dry filter paper
(grams)) / {impact area (m2))
The impact area, expressed in m2, is the area of the bottom surface 9110 of
the impact
portion 9107. The impact area is 0.00317 m2. The absorbent core material 9104
should
have an area slightly larger than that of the impact area of the surface 9110.
Water Vaoor Transmission Rate
When referring to Fig. 2, the test spedmen (210) having a diameter of about
120 mm is
positioned centered in a flat out condition over a 75 mm deep cylindrical cup
(220) with a
circular opening (222) of 50 mm inner diameter, which has been Red up to about
10 mm
below the upper end with distilled water (228). The sample is supported by a
cylindrical
rim (224) at the top of the cup, of about 120 mm diameter. The sample is
covered by a
cover lid (230) of a inner diameter to fit the outer diameter of the rim. The
lid has a
centered opening (232) corresponding to the opening 222 of the cup opening,
and a
flange (240) to allow fixation of sample and o minimize evaporation losses at
the side,
extending approximately 70 mm. The lid has a weight of approximately 238.5 g.

CA 02672562 2009-07-27
26
The assembly is weighed and positioned into a dimate chamber, such as
available from
WTB Binder, 'Tutilingen, Germany, type 377200990031.00 at 33 C 20% RH, with
high air
circulation rate of about 15cm/sec air velocity.
After 5 hrs, the assembly is removed from the chamber, and reweighed. The
Water
Vapor Transmission Rate Is calculated from the loss per time unit and opening
area (the
latter being 1963.5mm2), and expressed in units of g/m2/24hrs.
For very different rates, the evaporation time in the chamber can be adjusted,
such as to
2hrs for very permeable materials, or to 24 hrs for materials with low
permeability.
WVTR of full Product
The equipment described above can also be used to determine WVTR of samples
having higher caliper such as dry or wet diapers. In this case, a circular
sample having a
diameter of 109 mm is applied at the cup rim surface. To avoid exchange with
the
environment, a glass ring having an outer diameter of 120mm, an inner diameter
of
110mm, and a height of !ample caliper minus lmm is put around the sample.
When evaluating dry articles, it has to be taken into account that a dry
article acts as a
desiccant, that is, absorbs water vapor until reaching saturation. This effect
can be
minimized by equilibrating the sample prior to determining WVTR.
For equilibration, a circular 109 mm diameter cut out piece of the article Is
placed in a
suitable box, backsheet facing the environment. This equipment is placed for
about 48
hrs inside a climate chamber of the type as described in the above, at 33 C,
90%RH,
maximum ventilation (15 crnts). When removing the sample from the chamber, the

starting weight of equilibrated article Is recorded. As described in the
above, the
equilibrated piece Is then placed on the surface of the cup filled with water
with
badcsheet facing down to the water, topsheet facing to the environment The
glass ring is
placed around the sample.
The equipment is placed in the climate chamber as above, and after removing it

therefrom, the weight of complete equipment is recorded, as well as the end
weight of the
test specimen, to account for further absorption of vapor or evaporation from
equilibrated
article through the topsheet to environment

CA 02672562 2009-07-27
27
When evaluating wet articles. it has to be taken into account that wet
articles can show
additionally significant evaporation from loaded core through topsheet to
environment.
Thus, weight loss of equipment is not only due to diffusion of water vapor
from cup
through the product to the environment, but also due to evaporation from
loaded article
through topsheet to environment. Instead of the equilibration as for the dry
article, the
cut-out piece is now evenly loaded with log Saline per g of the test specimen.
The
starting weight of the test specimen is recorded accordingly, and so is the
starting weight
of the filled cup with water only (i.e. no sample).
The loaded test specimen Is placed on the surface of the filled cup filled,
the badcsheet
facing down to the water, topsheet facing to the environment, and the
protective ring is
added to surround the sample.
The equipment is placed In the climate chamber as above, and after removing it

therefrom, the weight of complete equipment is recorded, as well as the end
weight of the
test specimen, to account for further absorption of vapor or evaporation from
equilibrated
article through the topsheet to environment
There are two equivalent possibilities how to calculate VVVTR from the above
measurements for wet diapers:
= (start weight of cup with water only - end weight of cup with water
only)/(Time x
opening area);
= ( (start weight of complete equipment - end weight of complete equipment) -
(start
weight of wet diaper - end weight of wet diaper)) / (rime x opening area).
Wet Article Relative Humidity Differential
Temperature and relative humidity vary between body sites under the diaper due
to
loading pattern, babies activity and emotional state, and environment, such as
room
conditions. A multi point measurement provides the opportunity to monitor
simultaneously
conditions at several locations underneath the diaper.
Particular interest Iles in the understanding of change In conditions between
locations
corresponding to the loaded and non-loaded areas of the diaper. Typical diaper
users
change the diaper between 3 to 12 hours. Within this period on average the
baby has
loaded the diaper with 34 gushes of urine. Therefore, a partially loaded
diaper may be

CA 02672562 2009-07-27
28
worn for several hours before being changed. Thus, the conditions under the
article
when worn, i.e. in the space between the article and the skin of the wearer,
are
monitored at predetermined locations of the sensors in this space.
The microdimate as a function of body temperature and water evaporation may
also
change in response to babies activities and emotional state. To correlate
potential
nicrodimate changes babies can be supervised during the measurement period by
their
parent(s)/guardian(s) who record specific events, activities and times in a
diary.
Further, the micro-climate within the article is dependent on the room
conditions.
Henceforth, it has been found particularly useful to include a reference
measurement
point on the wearer, but not covered by the article which Is evaluated, but
only by normal
clothing, e.g. conventional underwear.
The present method and the particular equipment used herein should be set up
with
particular consideration of safety and hygienic conditions, such as the
Declaration of
Helsinki Recommendations guiding physicians In biomedical research involving
human
subjects, as adopted by the 18th World Medical Assembly, Helsinki, Finland,
June 1964
and its further amendments.
The Temperature and relative Humidity sensoring device consists of temperature
(T) and
relative humidity (RH) sensors, data-loggers to store data and a harness
carrying the
sensors and the data-logger.
Fitting the Temperature and Relative Humidity Monitoring System as described
in more
detail hereinafter, and changing diapers will preferably take place in a
separate room.
Before fitting the Monitoring System to the baby the sensors and cables will
be fixed onto
the harness with medical tape. The cables will be connected to the data-
logger. Excess
cables and the data loggers will be stored and fixed in the data-logger bag at
the back of
the harness.
The complete harness will be fitted on the baby with the help of the parent
and/or
guardian during the change of the diaper. The Monitoring System is fitted onto
the baby
such that all sensors on the harness face the diaper side. The elastics of the
harness will

CA 02672562 2009-07-27
29
be carefully adjusted to the baby to avoid skin marks. Following the
adjustment of the
harness a diaper is fitted over the Temperature and Relative Humidity
Monitoring System
carefully avoiding dislocation of the sensors. After fitting and diaper change
the baby will
be taken to a separate room for the wear period. The babies may not wear
underwear
over the diaper, if climatic conditions allow.
Monitoring System Wearing Period
The Monitoring System wearing period may last up to 12 hours. During the
wearing
period of the Monitoring System and the diaper the babies can be entertained
by their
parent and/or guardian. Babies may be encouraged by parents or guardians
perform
playful tasks (i.e. like in play groups) and/or to act as they like. A diary
of the activities
can be kept by the parent and/or guardian as appropriate for the specific
study objective.
Alternatively, the activities can be recorded on video for evaluation of
activities at a later
time.
Controlled Diaoer Loading
Depending on the specific study objective diapers may be loaded with
cumulative gushes
of "artificial urine" (i.e. physiological saline) up to the desired
representative loading in
view of the design and intended use of the article. For example, to represent
an overnight
usage of a MAXI size diaper (i.e. Intended for an about 9 to 18kg baby) a
total volume of
300 ml has been found suitable. The "artificial urine" will be prepared as
described herein
and warmed up to 37 C prior to loading. Diapers may be pre-loaded immediately
to fitting
or loaded 1n-use. Loading in-use will be performed using soft flexible tube
with rounded
tip at a controlled loading rate and volume.
Study size
It is estimated that In total approximately 5 babies will need to be recruited
to provide a
meaningful basis. Selection criteria may be set, such as relating to generally
healthy
babies of both sexes, weighing more than 7 kg and being elder than 6 months
(corresponds to Maxi- or larger size users).
Temoerature & Relative HumidItt Monitoring System Information

CA 02672562 2009-07-27
30 -
The monitoring system comprises three essential elements, namely a harness for
fixing
the system on the wearer, the sensors for measuring temperature and relative
humidity,
and the data logging system.
The harness Is designed to allow accurate positioning and fixing of the
sensors on the
wearer, and to provide means for carrying the data logging system. The harness
needs
to be made of skin friendly material. Materials described below are combined
as in the
following configuration.
A suitable design for the harness has been found by comprising a waist belt to
be fitted
around the waist of the wearer, and further comprising fixation elements
fitted between
the legs of the wearer.
A typical harness can be seen in Fig.3 as a schematic diagram, and in Fig.4 as
a
photograph fitted on a baby mannequin.
Sensorboxes and cables are fixed on the harness with an adhesive tape, such as

LEUKOSILIcru. The bag for the data loggers is made out of cotton. It is
equipped with 4
snap-fasteners to be able to remove the data loggers. The bag is tightened to
the
harness via mechanical fasteners. Data loggers are additionally coated by PU
foam to
achieve more comfort.
Further particularly suitable materials have been found as useful as follows.
The skilled
person will be readily enabled to replace materials by equivalent ones, or to
adjust sizes
to other sizes of the wearer, except for the sensors location, which is an
essential
element of the present invention.
An athletic supporter (lock-strap" or "Tiefschutz") (320)such as available
from Adidas,
AG, Germany, is sewn together with Rubber straps (330) such as available from
Wenco
Service Marketing, Duesseldorf, Germany, as "Baby Elastic" and conventional
"popper
buttons" to the described harness. Medical tapes, such as available form
Beiersdorf AG,
Hamburg, Germany, and Velcro TM type hook and loop closure systems (340) are
used to
close the harness and to fix it at the wearers body. Conventional cotton
fabric can be
used as bag for the data logger (310).

CA 02672562 2009-07-27
31
The harness can be replaced by other means to fix the sensors, and the logger
appropriately, such as by stretch-pants, or topical adhesives applied to fix
the sensors
directly on the skin of the wearer, as long as this fixation means does not
impede the
functionality of the erode, and it should further have a minimal effect on the
climate within
the article, and on the skin.
QataBa2LIMIQII
The climate data as generated by the sensors as described herein are gathered
by a
data logging system worn by the wearer, or a data transmission system
connected to a
data logging system physically located away from the wearer. The connection
between
the transmission system and the data logging system is preferably not executed
by fixed
cables, but rather by cable-less systems, such as radio signals or infra-red
data
transmission systems.
A particularly suited system Includes a data-logging system to be worn by the
tested
person, wherein the data are recorded during the test period, and from where
these data
can be read into a data processing unit after the testing.
A specific example is Smart Reader Plus, available from Status instruments
Ltd,
Tewkesbury, United Kingdom, connected via an insulated flat four wire cable
such I.D.C.
Flachbandkabel, form RS Components GmbH Morfelden-Walidorf, Germany.
Sensors and Sensor box '
The sensors are particularly designed to measure both temperature and relative
humidity
at small dimensions, and compatible with hygienic and safety requirements
during the
resting.
The sensors used for the Monitoring System should have the following accuracy,
which
should be maintained during data logging, transmission, and/or processing.
Temperature: 0.2 C
Relative Humidity: 2 %

CA 02672562 2009-07-27
32
A suitable temperature sensor is a precision thermistor, as from Omega
Precision
Therrnistor Resistance Omega Engineering Inc., Stanford, USA.
As suitable relative humidity sensor is Capacitive Humidity Sensor, such as
available
from OHMIC Instruments Co., Maryland. USA, under the designation HC 700.
The sensors can be affixed to the harness by conventional, such as dispersion
adhesives, shrinking tubes, and/or casting polymers, such as of the ABS type.
All relative humidity sensors are cast into a plastic box (17x11x4 mm, see
Figure 5,
hereafter called sensor box). Sbc out of seven temperature sensors are also
included in
these sensor boxes. The remaining temperature sensor is isolated with a
shrinking tube
and will be placed inside the absorbent part of the diaper. The sensor boxes
are
connected with the data loggers via a 4-wire isolated cable.
Cleaning Agents
Before usage, all sensor boxes will be disinfected by 15 minutes incubation in
a 6%
solution of Gigasept FF in distilled water. Afterwards, they will be washed by
immersion
for 5 minutes in distilled water and reused when they are dry again. If there
Is any
contamination of baby's excrement, sensors will either be cleaned before
disinfecting or
discarded.
The harness can washed in a regular washing machine with conventional washing
powder at a temperature of 95 C.
Electrical parts:
Two coupled data loggers are stored In the data logger bag at the rear side of
the
harness. Data loggers do not come in direct contact with the skin. For
improved wearing
comfort the data loggers are wrapped in a soft PU foam material.
Each data logger unit is powered by one 3 V battery of about 24 mm diameter.
The
batteries are secured inside the data loggers with a firm clip. Furthermore,
the four point
clip button closure system of the data logger bags provides additional
protection from

CA 02672562 2009-07-27
33
accidental access to batteries. Constant supervision of parents or guardians
will further
ensure that babies have no access to the batteries.
The cables connecting the data loggers with the sensor boxes are as small in
width as
the harness elastics and are fixed via the medical tape to that side of the
elastic which is
not in contact with the skin. The cable insulation consists of flexible PVC.
PVC is an inert
polymer with a good safety profile and used in commercial and medical
applications (e.g.
urine bags, flexible catheters).
The sensor boxes contain the temperature and relative humidity sensor. The
relative
humidity sensor lies protected under a cover made of a coated nickel alloy.
The sensor
boxes are fixed to the harness on that side which Is not in contact with the
skin.
The following describes a typical set up for carrying out the test, though of
course
particular elements such as of the babies activities, clothing etc. can be
varied.
Preferably, babies should be healthy, and the number of babies In one group
should be
kept small, such as 5 babies. Normal hygienic precautions should be taken,
such as
washing equipment and clothing used on the babies and using hand
disinfectants.
Equipment vulnerable to damage in machine washing (e.g. electrical parts such
as
sensor boxes and wires) will be disinfected by immersion in a solution of a
disinfectant.
Positioning of the sensors
The Temperature and Relative Humidity monitoring system consists of
Harness with temperature (T-) and relative humidity (RH-) sensorboxes and/or
pure RH
sensor, to be worn underneath the article. Preferably, five T-/RH sensors and
one RH
sensors are used. A further 1-sensor is further placed inside the article. A
further
reference sensor is applied outside the artide.
The 1-sensor is applied from the outside after the article is applied on the
wearer. and
the sensor is applied through the backsheet to be positioned closely in the
loading region
of the article, affixed e.g. by adhesive tape.
The reference sensor is applied outside the article in the rear waist part at
the right hip
such as by mechanical fastener. Since the part is not underneath the hygienic
article, the

CA 02672562 2009-07-27
34
reference sensor is located on the harness towards the outside of the harness
(i.e. on the
opposite side to the one oriented towards the skin of the wearer) and is
covered by the
cotton clothing.
For the determination of the result of the measurement, the signals of the
sensors
covered by the absorbent article are averaged, expressed and calculated to a
tenth a
percent.
To determine the Wet Article Relative Humidity Differential, the relative
humidity value of
the reference sensor (i.e. the one not covered by the article, but by terry
cloth only) Is
deducted from the average relative humidity values. =
Under most circumstance, the result will be a positive value. In case that the
coverage by
the article will result in a reduced relative humidity, the result will be
negative.
Evaporation Rate from Loaded Absorbent Article
This test method relates to an absorbent article. A rectangular test specimen
of TO mm
(in transverse direction of the article) by 100 mm (in longitudinal direction
of the article) is
cut by suitable scissors or a cutting blade from a representative part of the
absorbent
core, such as transversely centered, and from about 6 cm from front core edge.
The dry weight is recorded, and the specimen is placed in a glass box of about
72 mm by
102 mm, and about 40 mm high without lid, with backsheet down, arid the
topsheet
facing to environment.
The specimen is loaded with 10 g of 0.9% saline solution per gram weight of
the
specimen, whereby the liquid Is evenly distributed over the area, thereby
avoiding the
wetting of the glass box.
The complete weight of the glass box with the loaded specimen is recorded.
The equipment is placed into a climate chamber such as available from WTB
Binder,
Tuttlingen, Germany, type 37720099003100 at 33 C +/- 2 , at 50% relative
humidity
(RH) +/- 3%. The ventilation is adjusted to provide an air flow velocity of
about 15 crn/sec
over the opening of the glass box.
After two hours evaporation time, the end weight of the complete glass box
with the
specimen is recorded.

CA 02672562 2009-07-27
The area specific evaporation rate is determined
Evaporation Rate = (Start weight - End weight)/(Time x sample area).
whereby the start and end weight is the total weight of the glass box with the
specimen.
5
The above loading values have been found useful for baby diapers, espedally
for baby
diapers for babies of the size of about 9 to 18 kg, often referred to as MAXI
size. In case
of very different absorbent capacities of the absorbent article under
consideration, the
amount of liquid load should be adjusted to about 50 % of the theoretical
basis capacity
10 as defined herein.
Acauisition Test
This test should be carried out at about 22 +/- 2 C and at 35+/- 15% relative
humidity.
15 The synthetic urine used in these test methods is 0.9 % Saline solution.
Referring to Figure 6, an absorbent structure (410) is loaded with a 75 ml
gush of
synthetic urine at a rate of 15 m1/8 using a pump (Model 7520-00, supplied by
Cole
Parmer Instruments., Chicago, U.S.A.), from a height of 5 cm above the sample
surface.
20 The time to absorb the urine is recorded by a timer. The gush Is
repeated at precisely 5
minute gush intervals until the article is sufficiently loaded. Current test
data are
generated by loading four times.
The test sample, which can be a complete absorbent article or an absorbent
structure
25 comprising an absorbent core, a topsheet, and a backsheet, Is arranged
to lie flat on a
foam platform 411 within a perspex box (only base 412 of which is shown). A
perspex
plate 413 having a 5 cm diameter opening in its middle is placed on top of the
sample on
the loading zone of the structure. Synthetic urine is introduced to the sample
through a
cylinder 414 fitted, and glued into the opening. Electrodes 415 are located on
the lowest
30 surface of the plate, in contact with the surface of the absorbent
structure 410. The
electrodes are connected to the timer. Loads 416 are placed on top of the
plate to
simulate, for example a baby's weight A pressure of about 50g cm-2 (0.7psi) is
achieved
by positioning weights 416, e.g. for the commonly available MAXI size 20 kg.

CA 02672562 2009-07-27
36
As test fluid is introduced into the cylinder it typically builds up on top of
the absorbent
structure thereby completing an electrical circuit between the electrodes. The
test fluid is
transported from the pump to the test assembly by means of a tubing of about 8
mm
diameter, which is kept filled with test fluid. Thus the fluid starts to leave
the tubing
essentially at the same time the pump starts operating. At this time, also the
timer Is
started, and the timer is stopped when the absorbent structure has absorbed
the gush of
wine, and the electrical contact between the electrodes is broken.
The acquisition rate is defined as the gush volume absorbed (ml) per unit
time(s). The
acquisition rate is calculated for each gush Introduced into the sample. Of
particular
interest In view of the current invention are the first and the last of the
four gushes.
This test Is primarily designed to evaluate products generally referred to as
MAXI size
products for a design capacity of about 300 ml, and having a respective
Ultimate Storage
Capacity of about 300 ml to 400 ml. If products with significantly different
capacities
should be evaluated (such as can be envisaged for adult incontinence products
or for
smaller babies), the settings in particular of the fluid volume per gush
should be adjusted
appropriately to about 20% of the total article design capacity, and the
deviation from the
standard test protocol should be recorded.
Post Acquisition Collagen Rewet Method (refer to Flo. 71
Before executing the test, the collagen film as purchased from NATURIN GmbH,
Weinhein, Germany, under the designation of COFF1 and at a basis weight of
about
28g/m2 is prepared by being cut into sheets of 60 mm diameter e.g. by using a
sample
cutter device, and by equilibrating the film in the controlled environment of
the test room
(see above) for at least 12 hours (tweezers are to be used for all handling of
the collagen
film).
At least 5 minutes, but not more than 6 minutes after the last gush of the
above
acquisition test is absorbed, the cover plate and weights are removed, and the
test
sample (520) is carefully placed flat on a lab bench.
4 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,
and covered by perspex plate (530) of 90 mm diameter, and about 20 mm
thickness. A

CA 02672562 2009-07-27
37
weight (540) of 15 kg is carefully added (also centered). After 30 +/- 2
seconds the
weight and perspex plate are carefully removed again, and the collagen films
are
reweighed.
The Post Acquisition Collagen Rewet Method result is the moisture pick up of
the
collagen film, expressed In mg.
It should be noted further, that this testing protocol can be adjusted easily
according to
specific product types, such as different baby diaper sizes, or adult
incontinence articles,
or catamenial articles, or by the variation In the type and amount of loading
fluid, the
amount and size of the absorbent material, or by variations in the applicable
pressure.
Having once defined these relevant parameters, such modifications will be
obvious to
one skilled In the art. When considering the results from the adjusted test
protocol the
products can easily be optimizing these identified relevant parameter such as
in a
designed experiment according to standard statistical methods with realistic
in use
boundary conditions.
Drip caoacity
The drip capacity test described here is based on a standard and industry wide
applied
raw material test for airfelt (fluff) pulp. The test was initially developed
to evaluate the
degree to which a fibers can acquire, transport (distribute) away from the
loading point
and retain a load of synthetic urine in a fiber web. A slight modification of
the test is used
to simulate more in-use conditions.
In the acquisition-drip test a 75mi gush of synthetic urine (0.9 % saline) is
applied to a
fiber web supported on a wire mesh (porous) at a rate 15 mi/sec. The
(saturated) drip
capacity is then determined from the fluid that is retained in the fibrous
material after the
gush.
To execute the test, a sample pad 7.5 cm x 25 cm is weighed and placed on a
large
mesh wire screen positioned on a drip tray (like In the diagram) which is then
mounted on
a weight balance.
75m1 of Synthetic urine is introduced via a pump (the same pump used and
detailed in
the acquisition test) into the center of the sample at a rate of 15 0.25
ml/sec.

CA 02672562 2009-07-27
38
By suspending the mesh screen on a balance one can determine closely the
amount of
urine retained by the sample and urine passed ,into the drip tray. This helps
to minimize
variations of the pump delivering the urine.
Note the pump delivery rate is confirmed prior to each run.
The drip capacity is then given as the ratio:
Urine retained on saturation (ml)
Dry Weight of sample (g)
Optionally, the ''drip time" can be recorded, i.e. the time difference between
the start of
loading the structure and the time when the first drop falls out of the
sample.

Representative Drawing