Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE FOR HANDLING BODY LIQU1~7S WHICH TRANSPORTS BODY
s LIQUID BY SIPHONING
to
FIELD OF THE INVENTION
The present invention relates to a process for handling body liquids such as
is urine, sweat, saliva, blood, menses, purulence, or fecal material, and to
devices
carrying out such processes. The invention further relates to disposable
absorbent articles such as baby diapers or training pants, adult incontinence
products, and feminine hygiene products and other body liquid handling
articles
such as catheters, urinals, and the like.
Devices for handling body liquids are well known in the art and are
frequently used for a wide variety of purposes. For example, the devices serve
2s hygienic purposes such as diapers, sanitary napkins, adult incontinence
products, underarm sweat pads, wound dressings, and the like. Accordingly such
devices have been designed to cope with a large variety of different body
liquids
such as for example urine, sweat, saliva, blood, menses, purulence, fecal
material, and the like.
Typically, it is desirable for such devices for handling body liquids to
acquire
the body liquid and at a first region of the device, transport the body liquid
away
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from the zone of acquisition, and finally store the liquid in -a second
region, the
designated liquid storage zone. The reasons for transporting the body liquid
away from the zone of acquisition are manifold. These reasons include the
creation of unwanted bulk close to the point of liquid discharge from the body
and
s the avoidance of prolonged contact of the body liquids with the skin. The
body
liquid may either be transported in a direction perpendicular to the surface
of the
acquisition zone, i.e. into the bulk of the device, or the body liquids may be
transported in a direction parallel to the surface of the acquisition zone and
away
from the point of acquisition. The transportation of Liquid in these devices
is
i o typically achieved by means of capillary suction.
Capillary suction, however, has certain inherent limitations. In particular
when it is desired to transport liquid against gravity, the capillary suction
needs to
be increased by decreasing the size of the capillaries. On the other hand, a
~ s capillary having a decreased pore size exhibits a higher resistance to
liquid flow
through the capillary. Hence, the combination of high capillary suction and
high
liquid flow rates can only be achieved by providing a large number of small
capillaries which in turn leads to a large total cross-section of the device.
It has been suggested in PCT patent application WO 94/03214 {Lawrence)
to remove liquid from the point of acquisition by means of siphoning. Therein,
gravity or vacuum have been taught as the driving forces for liquid removal.
Both
driving forces, however, exhibit inherent disadvantages. When gravity is used
as
the driving force, the functionality of the device depends on its orientation
in
:'s space, i.e. the storage region must always be lower than the acquisition
region.
Hence, applicability of liquid removal systems relying on gravity is limited.
When
vacuum is used as the driving force, a high mechanical effort is required to
maintain the vacuum. Hence., in this case the complexity of the device limits
the
scope of possible applications. Furthermore, the liquid in this device is
stored
ao while still being relatively mobile which might create problems with
respect to
rewet and squeeze-out.
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Hence, it is an object of the present invention to overcome the problems
posed by the prior art devices for handling body liquids.
s It is a further object of the present invention to provide a process for
handling body liquids comprising a step of transporting the liquid by
siphoning
and a step of storing the liquid by either capillary or osmotic pressure.
It is a further object of the present invention to provide a device for
handling
~o body liquids which transports liquid by siphoning and which stores the
liquid by
either capillary or osmotic pressure.
It is a further object of the present invention to provide a device for
handling
body liquids comprising a liquid transport member which is substantially
is geometrically saturated before the intended use of the device.
It is a further object of the present invention to provide to a device for
handling body liquids comprising liquid transport member which comprises free
liquid before the intended use: of the device.
SUB, ARY OF THE INVENTION
The present invention provides a process for handling body liquids
comprising the step of transporting the body liquids from an acquisition
region to
2s a storage region by siphoning. The step of transporting body liquid by
siphoning
comprises the steps of:
- providing a liquid transport member being substantially geometrically
saturated with liquid before the first step of acquiring liquid; the liquid
saturating the liquid transport member being in liquid communication with
3o the liquid acquisition region;
- providing a liquid storage member in liquid communication with the liquid
transport member, the liquid storage member being positioned inside the
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a
storage region;
- acquiring liquid disposed onto the acquisition region into the liquid
transport member;
- replacing at least a portion of the liquid saturating the liquid transport
s member by the acquired liquid;
- storing at least a portion of the replaced liquid in a storage member.
The process of the present invention is characterized in that the liquid is
stored in a storage member by a means selected from the group of capillary
no pressure, osmotic pressure.
It is another aspect of the present invention to provide a device for handling
body liquids designed to carry out the process of the present invention.
r.s It is another aspect of the present invention to provide a device for
handling
body liquids having at least one liquid acquisition region and at least one
liquid
storage region. The storage region stores liquid by a means selected from the
group of capillary pressure, osmotic pressure. The device for handling body
liquids comprises a liquid transport member transporting liquid from the
~~o acquisition region to the liquid storage region. The device for handling
body
liquids of the present invention is characterized in that the liquid transport
member is substantially geornetrically saturated before the intended use of
the
device.-..
~a It is another aspect of the present invention to provide a device for
handling
body liquids having at least one liquid acquisition region and at least one
liquid
storage region. The storage region stores liquid by a means selected from the
group of capillary pressure, osmotic pressure. The device for handling body
liquids comprising a liquid transport member transporting liquid from the
..o acquisition region to the liquid storage region. The device for handling
of the
present invention is characterized in that the liquid transport member is
substantially geometrically saturated with free liquid.
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S
DETAILED DESCRIPTION OF THE INVENTION
Process of Si honing
s It is one aspect of the present invention to provide a process for
transporting body liquids from an acquisition region to a storage region
comprising a step of transporting the body liquid by siphoning.
The term "body liquids'" as used herein refers to liquids and in particular
io aqueous liquids which are e:xudated or otherwise produced by the mammalian
body at different locations of the body such as urine, sweat, saliva, blood,
menses, purulence, fecal material, and the .like. The term "device for
handling
body liquids" as used herein refers to devices which are able to act on body
liquids. Typical actions of such devices include but are not limited to
acquiring,
is transporting, distributing, storing, modifying, and the like. Generally,
such devices
include but are not limited to absorbent articles such as diapers, training
pants,
sanitary napkins, pantiliners, tampons, adult incontinence products, bed mats,
wound plasters, sweat pads, wound covers and the like; catheters used to
collect
urine from bladders of mobile and immobile patients; urine collection devices
o such as urinals and in particular portable urinals; blood acquisition
devices and
saliva acquisition devices for medical uses; body liquid sampling devices; and
the
like.
Definition oy~~jna
:>.s The term "siphoning" refers to a process in which liquid is transported
from
an acquisition region along a liquid transport member to a storage region, in
which the liquid transport member is substantially geometrically saturated
before
the intended use of the device, and in which at least a portion of the liquid
acquired at the acquisition rec,~ion replaces at least a part of the liquid in
the liquid
:;o transport member which in turn is stored in the storage regions.
Generally,
storage of the liquid happens on a time scale which is much shorter than the
average time interval between two subsequent loadings. In some instances, it
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may happen that there exists a certain delay between acquisition of liquid
into the
liquid transport member and storage of the replaced liquid in a storage
region.
Such a delay may be caused by a volume increase of the liquid transport
member following acquisition of the liquid. The process of siphoning is
generally
s reversible, i.e. the liquid may be transported in the opposite direction
depending
on external conditions such as applied pressure and the like. "Siphoning" as
used herein includes internal siphoning as well external siphoning which
processes will be defined hereinafter. In particular, the step of transporting
liquid
by siphoning comprises the steps of:
~o - providing a liquid transport member being substantially geometrically
saturated with liquid before the first step of acquiring liquid into the
liquid
transport member, the liquid saturating the liquid transport member be in_
liquid communication with the acquisition region;
- providing a liquid storage member in liquid communication with said
is liquid saturating said liquid transport member, said storage member
being positioned in the storage region;
- acquiring liquids disposed onto the acquisition region into the liquid
transport member;
- replacing at least a portion of the liquid saturating the liquid transport
:!o member with the acquired liquid;
- storing at least a portion of the replaced liquid in the storage member, the
storage member storing the liquid by means selected from the group of
capillary pressure, osmotic pressure.
~!s The term "geometrically saturated" as used herein refers to a region of a
porous material in which the liquid accessible void spaces have been filled
with a
liquid. The void spaces referred to in this definition are those which are
present in
the current geometric configuration of the porous material. In other words, a
geometrically saturated device may still be able to accept additional liquid
by and
..o only by changing its geometric configuration for example by swelling,
although all
voids of the device are filled with liquid in the current geometric
configuration. A
device for handling liquids is called geometrically saturated, if ail porous
materials
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that are part of the device .and intended for liquid handling are
geometrically
saturated.
The term "porous material" as used herein refers to materials that comprise
s at least two phases a solid material and a gas or void phase and optionally
a
third liquid phase that may be partially or completely filling said void
spaces. The
porosity of a material is defined as the ratio between the void volume and the
total volume of the material, measured when the material is not filled with
liquid.
Non-limiting examples for porous materials are foams such as polyurethane,
i o HIPE (see for example PCT patent application W094113704), superabsorbent
foams and the like, fiber assemblies such as meltblown, spunbond, carded,
cellulose webs, fiber beds and the like, porous particles such as clay,
zeolites,
and the like, geometrically structured materials such as tubes, balloons,
channel
structures etc. Porous materials might absorb liquids even if they are not
~ s hydrophilic. The porosity of the materials is therefore not linked to
their affinity for
the liquid that might be absorbed.
The term "substantially geometrically saturated" as used herein refers to a
member in which at least 90"/0 of the macroscopic void volume of the member
ao are geometrically saturated, preferably at least ~ 95% of the macroscopic
void
volume of the device are geometrically saturated, more preferably 97% of the
macroscopic void volume of the device are geometrically saturated, most
preferably 99% of the macro;>copic void volume of the device are,
geometrically
saturated.
2s
Optionally, the step of providing a liquid transport member which is
substantially geometrically saturated with liquid may comprise further
individual
steps. For example, the step may comprise a first step of providing a liquid
transport member and a second step of activating said liquid transport member.
3o The step of activating may comprise the step of substantially geometrically
saturating the liquid transport member for example by disposing liquid onto
the
liquid transport member which in turn is absorbed to either liquid transport
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member. Alternatively, the step of activating may comprise a step of
manipulating the intended acquisition region in order to render that region
functional for example by removing a release paper or by wetting at least a
portion of the intended acquisition region.
s
Optionally, the process for handling body liquids according to the present
invention comprises the following further steps:
- providing a liquid acquisition member
- acquiring body liquid into said acquisition member
~o - transporting at least a portion of said acquired body liquid into said
liquid
transport member.
Internal Si~~honi~
The term "internal siphoning" as used herein refers to a siphoning process
~s in which the storage region is in direct liquid contact with the liquid
saturating the
liquid transport member. In this case, the storage member may being positioned
inside the liquid transport member. Hence, such a storage member is able to
directly acquire liquid from the liquid transport member and in particular
that liquid
which has been replaced by recently acquired liquid. Optionally, the liquid
2o storage member in this case may also be substantially geometrically
saturated
with liquid before the intended use.
External Siphon
The term "external siphoning" refers to a siphoning process in which the
2s storage region is positioned outside of and in liquid communication with
the liquid
transport member. In this case, liquid be transported from the liquid
transport
member to the liquid storage member has to be discharged from the liquid
transport member at a liquid discharge region.
3o Optionally, at least one of the storage regions is in direct contact with a
liquid discharge region. Alternatively, the process for handling body liquid
according to the present invention comprises a further step of transporting at
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least a portion of the liquid discharged from the liquid handling member to
the
liquid storage member.
~.iquid Transport Member
s The term "liquid transport member" as used herein refers to a device which
is capable of transporting liquid from a first region to a second region.
in the following, a suitable embodiment of the liquid handling member will
be described. The liquid handling member is assembled from an open celled
;ao foam material which is completely enveloped by a membrane. A suitable
membrane material is available from SEFAR of Ruschlikon, Switzerland, under
the designation SEFAR 03-20/14. A suitable foam material is available from
Recticel of Brussels, Belgium, under the designation Bulpren S10 black. A
suitable technique to completely envelope the foam material with the membrane
~ s material is to wrap the membrane material around the foam material and to
subsequently heat seal all open edges of the membrane material. It will be
readily apparent to the skilled practitioner to choose other similarly
suitable
materials. Depending on the specific intended application of the liquid
handling
member, it may also be required to choose similar materials with slightly
different
2:o properties. After assembly, the liquid handling member is activated by
immersing
the liquid handling member in water or in synthetic urine until the liquid
handling
member is completely filled with liquid and until the membranes are completely
wetted with liquid. After activation, a part of the liquid inside the liquid
handling
member may be squeezed out by applying an external pressure to the liquid
2s handling member. If the activation of the liquid handling member was
successful,
the liquid handling member should not suck air.
Other liquid handling members suitable for the purposes of the present
invention are described for example in the PCT patent application No.
3o PCT/US98/13497 entitled "Liquid transport member for high flux rates
between
two port regions" filed in the name of Ehrnsperger et al. filed on June 29,
1998,
and in the following PCT patent applications co-filed with the present
application
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entitled "High flux liquid transport members comprising two-different
permeability
regions" (P&G case CM1840MQ) filed in the name of Ehrnsperger et al., "Liquid
transport member for high flux rates between two port regions" (P&G case
CM1841 MQ} filed in the name of Ehrnsperger et al., "Liquid transport member
for
s high flux rates against gravity" (P&G case CM1842MQ) filed in the name of
Ehrnsperger et al., "Liquid transport member having high permeability bulk
regions and high bubble point pressure port regions" (P&G case CM1843MQ)
filed in the name of Ehrnsperger et al. All of these documents are enclosed
herein by reference.
to
The particular geometry of the liquid handling member of the present
invention can be varied according to, the specific requirements of the
intended
application. If, for example, the liquid handling member is intended to be
used in
an absorbent article the liquid handling member may be defined such that its
~s zone of intended liquid acquisition fits between the legs of the wearer and
further
that its intended liquid discharge zone matches the form of the storage member
associated to it. Accordingly, the outer dimensions of the liquid handling
member
such as length, width, or thickness may also be adapted to the specific needs
of
the intended application. In this context, it has to be understood , however,
that
~~o the design of the outer form ~of the liquid handling member may have an
impact
on its performance. For example, the cross section of the liquid handling
member directly impacts on its liquid flow rates.
For application of the liquid handling member in a device for handling body
~~s ° liquids according to the present invention, the liquid handling
member may be
combined with a storage member. The term "liquid storage member" refers to a
device which is capable of acquiring and storing liquid. The volume of the
liquid
storage member may vary with the amount of stored liquid such as by swelling.
Typically, the storage member will imbibe the liquid by means of capillary
suction
..o and/or osmotic pressure. Other storage members may also use vacuum as a
means to store the liquid. The liquid storage member is further capable of
holding
at least a portion of the stored liquid under pressure. Suitable storage
members
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are well known in the art and may comprise for example a super absorbent
polymeric material such as polyacrylate. The storage member may further
comprise a fibrous structure, such as a pad of cellulosic fibers, in which the
particulate superabsorbent material is dispersed. A suitable absorbent gelling
s material is ASAP400 available from Chemdal Ltd., United Kingdom. Further
examples of suitable superabsorbent polymers, often also referred to as
"hydrogei forming polymer" or "absorbent gelling material", are described in
U.S.
Patent 5,562,646 (Goldman et al.), issued Oct. 8, 1996 and U.S. Patent
5,599,335 (Goldman et ai.), issued Feb. 4, 1997.
~o
In order to pick up the liquid discharged from the liquid handling member,
the storage member may be' placed in direct liquid communication with the
intended liquid discharge zone of the liquid handling member.
t s Further examples of suii:able superabsorbent polymers, often also referred
to as "hydrogel forming polymer" or "absorbent gelling material", are
described in
U.S. Patent 5,562,646 (Goldman et al.), issued Oct. 8, 1996 and U.S. Patent
5,599,335 (Goldman et al.), issued Feb. 4, 1997.
2o In one embodiment of the present invention, the liquid transport member of
the present invention is geometrically saturated or substantially
geometrically
saturated with free liquid. The term "free liquid" as used herein refers to
liquid
which is not bound to a specific surface or other entity. Free liquid can be
distinguished from bound liquid by measuring the proton spin relaxation time
T2
2:5 of the liquid molecules according to NMR (nuclear magnetic resonance)
spectroscopy methods well known in the art.
Device for handling bodyr ILiauyds
It is one aspect of the present invention to provide a device for handling
3o body liquids which comprises a liquid transport member according to the
present
invention. Such devices include but are not limited to disposable absorbent
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articles such as baby diapers or training pants, adult incontinence products,
and
feminine hygiene products and other body liquid handling articles such as
catheters, urinals, and the like.
s In one embodiment of the present invention, the device for handling body
liquids is a disposable absorbent article such as a diaper, a training pant, a
sanitary napkin, an adult incontinence device, or the like. Such an absorbent
article may further comprise a liquid pervious topsheet, a liquid impervious
backsheet at least partially peripherally joined to the topsheet. The
absorbent
io article may further comprise an absorbent core which may serve as a storage
member for the body liquid. l'opsheets, backsheet, and absorbent cores
suitable
for the present invention are well known in the art. In addition, there are
numerous additional features known in the art which can be used in combination
with the absorbent article of the present invention such as for example
closure
~ s mechanisms to attach the absorbent article around the lower torso of the
wearer.
