U.S. patent application number 10/923787 was filed with the patent office on 2005-02-03 for hydraulically entangled nonwoven material and method for making it.
This patent application is currently assigned to SCA HYGIENE PRODUCTS AB. Invention is credited to Strandqvist, Mikael.
Application Number | 20050022954 10/923787 |
Document ID | / |
Family ID | 29423484 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050022954 |
Kind Code |
A1 |
Strandqvist, Mikael |
February 3, 2005 |
Hydraulically entangled nonwoven material and method for making
it
Abstract
A wetlaid or foam formed hydraulically entangled nonwoven
material containing at least 30%, by weight, pulp fibres and at
least 20%, by weight, man-made fibres or filaments. The material
has a basis weight variation in a non-random pattern in that it
comprises a plurality of higher basis weight cushions protruding
from one major surface of the material. The cushions as a main
component comprise pulp fibres and are surrounded by a lower basis
weight network which as a main component comprises the man-made
fibres or filaments. The invention further refers to a method for
making the material.
Inventors: |
Strandqvist, Mikael;
(Lindome, SE) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Assignee: |
SCA HYGIENE PRODUCTS AB
GOTEBORG
SE
|
Family ID: |
29423484 |
Appl. No.: |
10/923787 |
Filed: |
August 24, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10923787 |
Aug 24, 2004 |
|
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10400673 |
Mar 28, 2003 |
|
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60367712 |
Mar 28, 2002 |
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Current U.S.
Class: |
162/115 ;
162/100; 28/105 |
Current CPC
Class: |
Y10T 428/24612 20150115;
D21F 11/00 20130101; D21H 27/02 20130101; D04H 1/495 20130101; Y10T
428/24603 20150115; Y10T 428/24595 20150115; Y10T 442/689 20150401;
D21F 11/002 20130101; Y10T 428/24479 20150115; D21F 1/0063
20130101; D21F 11/006 20130101 |
Class at
Publication: |
162/115 ;
162/100; 028/105 |
International
Class: |
D04H 003/02; D21F
011/00 |
Claims
1. A method of producing a nonwoven material comprising wetlaying
or foamforming a fiber dispersion to form a fibrous web containing
at least 30%, by weight, pulp fibres and at least 20%, by weight,
man-made fibres or filaments, calculated on the total weight of the
fibres in said fibrous web, and hydroentangling the fibrous web
followed by subsequent dewatering and drying, wherein at least part
of the hydroentangling step is performed on a foraminous support
member in the form of a moulded, close-meshed screen of a
thermoplastic material, said screen having apertures of
cross-dimensional size 0.2-4 mm and the distance between the
apertures being between 0.2-4 mm.
2. The method as claimed in claim 1, wherein the cross-dimensional
size of the apertures in said screen is 0.5-2 mm and the distance
between the apertures is between 0.5-2 mm.
3. The method as claimed in claim 1, wherein the fibrous web is
formed on a formation wire and is subjected to a first
hydroentangling while supported on said formation wire, and is then
transferred to said moulded, close-meshed screen where it is
subjected to a further hydroentangling.
4. The method as claimed in claim 3, wherein said further
hydroentangling is performed from an opposite side of the fibrous
web as compared to the first hydroentangling.
5. The method as claimed in claim 1, wherein the web after
dewatering is subjected to non-compacting drying.
6. The method as claimed in claim 5, wherein the non-compacting
drying is selected from through air drying and IR drying.
7. The method as claimed in claim 5, wherein no pressing of the
fibrous web takes place during dewatering and drying.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of co-pending application
Ser. No. 10/400,673, filed on Mar. 28, 2003, which is a
non-provisional of 60/367,712 filed Mar. 28, 2002 the entire
contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention refers to a wetlaid or foam formed
hydraulically entangled nonwoven material containing at least 30%,
by weight, pulp fibres and at least 20%, by weight, man-made
fibres. It further refers to a method of making such a
material.
BACKGROUND OF THE INVENTION
[0003] Hydroentangling or spunlacing is a technique introduced
during the 1970'ies, see e g CA patent no. 841 938. The method
involves forming a fibre web, which is either drylaid or wetlaid,
after which the fibres are entangled by means of very fine water
jets under high pressure. Several rows of water jets are directed
against the fibre, web which is supported by a movable wire. The
entangled fibre web is then dried. The fibres that are used in the
material can be natural fibres, especially cellulosic pulp fibres,
man-made staple fibres, which may be synthetic, e g polyester,
polyamide, polyethylene, polypropylene, or regenerated staple
fibres, eg viscose, rayon, lyocell or the like, and mixtures of
pulp fibres and staple fibres. Spunlace materials can be produced
in high quality to a reasonable cost and they possess a high
absorption capacity. They can e g be used as wiping material for
household or industrial use, as disposable materials in medical
care and in hygiene purposes etc.
[0004] Through e g EP-B-0 333 211 and EP-B-0 333 228 it is known to
hydroentangle a fibrous mixture in which one of the fibre
components is continuous filaments in the form of meltblown
fibres.
[0005] In WO 96/02701 there is disclosed hydroentangling of a foam
formed fibrous web. The fibres included in the fibrous web can be
pulp fibres and other natural fibres and man-made fibres.
[0006] During the hydroentanglement the fibre web is supported
either by a wire or a perforated, cylindrical metal drum. An
example of a hydroentanglement unit of this kind is disclosed in
for example EP-A-0 223 614. However, supporting members in the form
of wires of the type utilised in connection with paper production
is the most frequently occurring type as for example is shown in
EP-A-0 483 816. One disadvantage with using wires of this type is
that the fibre web, during the hydroentanglement, is exerted to a
strong action by the water jets and will penetrate into and get
caught between the wire threads. It may then be difficult to
separate the final product from the wire.
[0007] WO 01/88261 discloses the use of a moulded, close-meshed
screen of thermoplastic material as supporting member during
hydroentanglement of a fibrous web. The removal of the final
product from such screen is simplified as compared to a wire.
[0008] When making a nonwoven material, especially a material that
is intended to be used as a wiping material, there a many
properties that are important, such as absorptive capacity,
absorption speed, wet strength, softness, drapability, low linting,
high cleaning ability etc. It is however difficult to combine all
these properties in one and the same material. It is for example
possible to make cloth like, soft, strong and low linting
hydroentangled nonwoven material by using 100% synthetic fibres.
However the absorption properties of such a material will be low.
Materials containing a high amount of pulp fibres have a high
absorptive capacity, but a poor wet strength and high linting. The
wet strength and linting properties can be improved by the addition
of chemicals, such as wet strength agents and binders.
SUMMARY OF THE INVENTION
[0009] The object of the present invention is to provide a
hydroentangled nonwoven material that combines properties like wet
strength, absorptive capacity, softness and drapability. This has
been achieved by a wetlaid or foam formed hydraulically entangled
nonwoven material containing at least 30%, by weight, pulp fibres
and at least 20%, by weight, man-made fibres or filaments, said
nonwoven material having a basis weight variation in a non-random
pattern in that it comprises a plurality of higher basis weight
cushions protruding from one major surface of said material, said
cushions as a main component comprises pulp fibres and are
surrounded by a lower basis weight network which contains a
relatively higher amount of man-made fibres or filaments as
compared to the cushions.
[0010] It is believed that this specific structure provides:
[0011] a cloth like appearance of the material;
[0012] high strength due to the network of the man-made fibres;
[0013] high absorptive capacity provided by the high pulp content
cushions and the three-dimensional structure formed by these;
[0014] high softness and drapability due to the plurality of
bending indications provided by the network pattern.
[0015] The opposite major surface of the material is preferably
substantially smooth. This will improve the capability of the
material to wipe a surface dry from any remaining liquid.
[0016] The material preferably contains .sup.40%, and more
preferably at least 50%, by weight, pulp fibres. Preferably it
contains at least 30%, and more preferably at least 40%, by weight,
man-made fibres or filaments. The man-made fibres are in one
embodiment staple fibres of a length between 6 mm and 25 mm.
[0017] It is preferred that the material has an absorptive capacity
of at least 5 g/g water.
[0018] It is further preferred that the material has an absorption
speed, WAT, in MD of no more than 1.5 s/m, preferably no more than
1 s/m, and in CD of no more than 2.5 s/m, preferably no more than 2
s/m.
[0019] In a preferred embodiment the cushions have a length and
width between 0.2 and 4 mm, preferably between 0.5 and 2 mm. It is
further preferred that the distance between the adjacent cushions
is between 0.2 and 4 mm, preferably between 0.5 and 2 mm.
[0020] The present invention also refers to a method of producing a
nonwoven material as stated above, said method comprises wetlaying
or foamforming a fibre dispersion to form a fibrous web containing
at least 30%, by weight, pulp fibres and at least 20%, by weight,
man-made fibres or filaments, calculated on the total weight of the
fibres in said fibrous web, and hydroentangling the fibrous web
followed by subsequent dewatering and drying, wherein
[0021] at least part of the hydroentangling step is performed on a
foraminous support member in the form of a moulded, close-meshed
screen of a thermoplastic material, said screen having apertures of
the cross-dimensional size 0.2-4 mm the and the distance between
the apertures being between 0.2-4 mm.
[0022] Preferably the apertures in said screen are of the size
0.5-2 mm and the distance between the apertures is between 0.5-2
mm.
[0023] In one embodiment the fibrous web is formed on a formation
wire and is subjected to a first hydroentangling while supported on
said formation wire, and is then transferred to said moulded,
close-meshed screen where it is subjected to a further
hydroentangling.
[0024] Preferably said further hydroentangling is performed from
the opposite side of the fibrous web as compared to the first
hydroentangling.
[0025] In a preferred embodiment the web is after dewatering
subjected to non-compacting drying, such as through-air-drying, IR
drying or the like. In order to maintain bulk and absorbency of the
material preferably no pressing of the fibrous web takes place
during dewatering and drying.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention will below be described with reference to some
embodiments described in the accompanying drawings.
[0027] FIG. 1 is a schematic view of a device for hydroentangling a
fibrous web.
[0028] FIG. 2 shows a schematic perspective view, on an enlarged
scale, of a screen used for supporting the fibrous web during the
hydroentangling.
[0029] FIG. 3 is a picture taken of a nonwoven material according
to the invention on a magnification of about 30 times.
[0030] FIGS. 4 and 5 are electron microscope (SEM) pictures of a
nonwoven material according to the invention.
DESCRIPTION OF EMBODIMENTS
[0031] The device, which schematically is shown in FIG. 1, for
manufacturing a so-called hydroentangled or spunlaced material,
comprises a vessel 10, e g a pulper, in which a wet or foamed fibre
dispersion is prepared, which via a headbox 11 is distributed on a
foraminuous support member 12. This foraminuous support member 12
is preferably a wire of any conventional kind used in papermaking
industry and which is suited for formation and for a first
hydroentangling step to intertwine at least the man-made fibres
present in the web The formed fibrous web 13 is then subjected to
hydroentanglement from several rows of nozzles 14, from which water
jets at a very high pressure are directed towards a fibrous web,
while this is supported by the foraminous support member 12. The
fibrous web is drained over suction boxes 15. Thereby, the water
jets accomplish an entanglement of the fibrous web, i.e. an
intertwining of the fibres. Appropriate pressures in the
entanglement nozzles are adapted to the fibrous material, grammage
of the fibrous web, etc. The water from the entanglement nozzles 14
is removed via the suction boxes 15 and is pumped to a water
purification plant, and is then re-circulated to the entangling
stations.
[0032] For a further description of the hydroentanglement or, as it
is also called, spunlacing technology, reference is made e.g. to
the above-mentioned CA patent No. 841 938.
[0033] The fibrous web 13 is either wet-laid or foam-formed. In a
wet-laid process the fibres are dispersed in a liquid, normally
water, in a similar way as in a papermaking process and the dilute
fibre dispersion is deposited on the foraminous support member
where it is dewatered to form a continuous web-like material. The
fibre dispersion may be diluted to any consistency that is
typically used in conventional papermaking process. A foam forming
process is a variant of a wet-laying process and a surfactant is
added to the fibre dispersion, which is foamed, and the foamed
fibre dispersion is deposited on the foraminous support. A very
even fibre distribution is achieved in a foam forming process and
it is also possible to use longer fibres than in a conventional
wet-laying process.
[0034] The fibres used to form the fibre dispersion is a mixture of
cellulosic pulp fibres and man-made staple fibres or man-made
filaments. The pulp fibres can be selected from any type of pulp
and blends thereof. Preferably the pulp is characterized by being
entirely natural cellulosic fibres and can include cotton as well
as wood fibres. Preferred pulp fibres are softwood papermaking
pulp, although hardwood pulp and non-wood pulp, such as hemp and
sisal may be used. The length of pulp fibres may vary from less
than 1 mm for hardwood pulp and recycled pulp, to up to 6 mm for
certain types of softwood pulp. The fibre dispersion should contain
at least 30% by weight, calculated on the total fibre weight, pulp
fibres.
[0035] The man-made fibres may be any suitable synthetic fibres or
regenerated cellulosic fibres. Examples of commonly used synthetic
fibres are polyester, polyethylene, polypropylene, polyamide,
polylactides and/or coplymers thereof. Examples of regenerated
fibres are rayon, viscose, lyocell. The man-made fibres may be in
the form of staple length fibres. A preferred length of staple
fibres used in a wetlaying or foam forming process is between 6 mm
and 25 mm. The fineness of the fibres can vary between 0.3 dtex and
6 dtex. The fibre dispersion should contain at least 20% by weight,
calculated on the total fibre weight, man-made fibres.
[0036] The man-made filaments are preferably spunlaid or meltblown
filaments of suitable thermoplastic polymers, such as polyethylene,
polypropylene, polyamides, polyesters and polylactides. Copolymers
of these polymers may of course also be used, as well as natural
polymers with thermoplastic properties.
[0037] The web 13 is turned 1800 and transferred to a second
foraminous support member 16, which in a preferred embodiment is
constituted of a moulded, close-meshed plastic screen, as disclosed
in WO 01/88261. The plastic screen according to the invention can
consist of one layer, as shown in FIG. 2, or of two or several
layers applied on top of each other. Possibly, the screen can be
reinforced with reinforcement wires 17 which extend in the intended
machine direction of the plastic screen/entanglement wire 16.
Reinforcement wires can be arranged also in the transverse
direction of the screen, or both in the longitudinal and the
transverse direction. The production of the plastic screen can take
place e.g. in the way described in U.S. Pat. No. 4,740,409. The
plastic screen is provided with a plurality of apertures 18, which
will be described in greater detail below.
[0038] The web is hydroentangled a second time from several rows of
nozzles 19 while supported on the plastic screen member 16. The
second hydroentanglement takes place from the opposite side of the
fibrous web 13 as compared to the first hydroentanglement. The
fibrous web is drained over suction boxes 20.
[0039] Further dewatering of the fibrous web may take place over
suction boxes 21, while the web 13 has been transferred to a
dewatering wire 22. This further dewatering may optionally take
place while the fibrous web is still supported by the plastic
screen member 16.
[0040] The entangled material is then brought to a drying station
23 for drying before the finished material is reeled up and
converted. Drying can be performed by blowing hot air through the
fibrous web, by IR dryers or other non-compacting drying technique.
Preferably no pressing of the fibrous web takes place during
dewatering and drying thereof. The material may before conversion
be exerted to different kind of treatments, such as corona or
plasma treatment 24, treatment with chemicals of any desired kind
etc. Corona or plasma treatment is preferably made after drying
while chemicals may be added either to the fibre dispersion or
after dewatering of the web by spraying printing or the like.
[0041] In the embodiments shown in FIG. 2, the apertures 15 in the
screen 16 exhibit a rectangular shape, but it is evident that this
shape can be varied to any geometrical shape. The meshes in the
screen suitably exhibit an aperture size within the interval 0.2-4
mm, preferably 0.5-2 mm. The aperture size is herein defined as the
size between opposite side edges or corners. The apertures are
either of substantially the same size or of different sizes, and
are either uniformly distributed across the screen or arranged to
form patterns with alternating groups of apertures of different
sizes. Also the cross-sectional shape of the apertures in the
z-direction can be varied, and can be e.g. substantially
rectangular, alternatively convex or concave. The distance between
the apertures may vary between 0.2-4 mm, preferably between 0.5 and
2 mm. The distance between the apertures is defined as the shortest
distance between adjacent apertures.
[0042] In case the screen consists of two or several layers
arranged on top of each other, the different layers can exhibit
different aperture sizes among themselves, e.g. with larger
apertures in an upper layer and smaller apertures in a lower layer.
This is shown in WO 01/88261. In this way, fibres can penetrate
down into the larger apertures in the upper layer but be retained
by the lower layer during the entanglement.
[0043] The surface, which is intended to support the fibrous web,
can be substantially smooth, or exhibit a three-dimensional
structure in order to impart a corresponding three-dimensional
structure to the hydroentangled material.
[0044] Other foraminous supports such as wires and other types of
screens may also be used, which have apertures of the size stated
above.
[0045] When hydroentangling the fibre dispersion through the
apertured screen 16 the shorter pulp fibres, which are more easily
mobile, will to a higher extent follow the water that is drained
through the apertures 18 and be accumulated in said apertures,
while the longer man-made fibres which are less mobile and more
easily intertwined by the water jets, will to a higher extent stay
in place on the screen 16 and build up a strong fibrous
network.
[0046] This will result in a nonwoven material having a plurality
of cushions 25 protruding from one major surface of the material,
said cushions as a main component comprise pulp fibres 26 that
during drainage have accumulated in the apertures 18 of the screen
16. The term "main component" in this respect means that more than
50% by weight, preferably more than 60% by weight and more
preferably more than 70% by weight of the fibres present in said
cushions are pulp fibres 26. A minor proportion of the fibres in
the cushions 16 will of course be man-made fibres.
[0047] The pulp fibre cushions 25 are surrounded by a network 27,
which contains a relatively higher amount of man-made fibres 28 as
compared to the cushions 25. In a preferred embodiment more than
50% by weight, preferably more than 60% by weight and more
preferably more than 70% by weight of the fibres present in said
network are man-made fibres 28. The longer man-made fibres 28 are
more easily entangled and will intertwine with each other to form a
strong continuous network 27 which will impart high strength to the
material. The pulp fibre cushions contribute to the absorbency of
the material. This is shown in FIGS. 4 and 5 showing SEM-pictures
of a material according to the invention, and in which the
accumulation of pulp fibres 26 to form the cushions 25 can be seen.
It is further seen how these cushions 25 are surrounded by a
network. This is also seen from the light microscope picture in
FIG. 3.
[0048] In order to provide a pronounced cushion effect at least 30%
by weight and preferably at least 40% of the fibres in the material
should be pulp fibres and in order to provide a strong network of
man-made intertwined fibres at least 20% by weight and preferably
at least 30% by weight of the fibres in the material should be
man-made fibres.
[0049] The length and width dimensions of the cushions 25 will
correspond to the size of the apertures 18 of the screen 16 and the
width of the network strands 27 between the cushions 25 will
correspond to the distance between adjacent apertures 18 of the
screen 16.
[0050] The opposite major surface of the material is preferably
substantially smooth as compared to the first surface having a
pronounced three-dimensional structure provided by the plurality of
protruding cushions. This gives the material a two-sidedness with
one side the is more "rough" and adapted to remove and capture
liquids, viscous fluids and solid particles from a surface. The
opposite smooth surface is adapted to wipe a surface dry from
liquid.
[0051] Tests have been performed on materials produced as described
below. A foamformed fiber dispersion was made from water,
surfactant and a mixture of pulp fibres and man-made staple length
fibres. A surfactant was added to the water in an amount of 0.03%
by weight. The foamed fibre dispersion was laid on a wire and the
formation was made at an air content in the foam of 30-50% by
volume. The fibrous web was hydroentangled on the same wire used
for formation. The web was then transferred to a moulded,
close-meshed plastic screen as disclosed above, having holes of the
size 0.89.times.0.84 mm and a distance between the holes of 0.46
mm. The web was then hydroentangled from the opposite side. The
main part of the hydroentangling was made on the first wire in
order to give maximum strength to the material. The total energy
supply at the hydroentangling was about 200 kWh/ton material.
[0052] The fibrous web was then dewatered by vacuum suction boxes
and dried by so called through-air-drying (TAD).
[0053] The fibres used for forming the fibrous web had the
following composition:
[0054] Ex. 1: 25 wt % polyester (PET) from KoSa, 1.7 dtex/19
mm;
[0055] 17 wt % polypropylene (PP) from Fibervisions, 1.7 dtex/18
mm;
[0056] 58 wt % bleached sulphate pulp fibres from Korsnas, Vigor
Fluff.
[0057] Ex. 2: 40 wt % polypropylene (PP) from Fibervisions, 1.7
dtex/18 mm;
[0058] 50 wt % bleached sulphate pulp fibres from Korsnas, Vigor
Fluff.
[0059] As reference material was used a nonwoven wiping material
produced by SCA Hygiene Products AB under the trade mark E-Tork
Strong.TM.. It is made by wet forming a fibre mixture and
hydroentangling thereof. However there is not used any moulded,
close-meshed plastic screen, but the hydroentangling process is
performed on a conventional papermaking wire. The material does not
have the patterned three-dimensional structure as claimed by the
present invention, but a more uniform fibre distribution. The fibre
composition in the reference material was as follows:
[0060] Ref.: 25 wt % polyester (PET) from KoSa, 1.7 dtex/19 mm;
[0061] 17 wt % polypropylene (PP) from Steen, 1.7 dtex/18 mm;
[0062] 58 wt % bleached sulphate pulp fibres from Korsns, Vigor
Fluff.
[0063] Thus the fibre composition is the same as for Ex. 1 except
that the PP fibres are from another manufacturer.
[0064] Evaluations concerning strength properties both in dry and
wet conditions, absorbency, wicking rate were performed and gave
the results presented in Table 1 below:
1 TABLE 1 Ex. 1 Ex. 2 Ref. Grammage g/m.sup.2 76.4 88.0 83.0
Thickness .mu.m 623 641 357 Bulk 2kPa cm.sup.3/g 8.2 7.3 4.3
Tensile stiffness MD N/m 30230 38385 57518 Tensile stiffness CD N/m
2096 6488 6689 Tensile stiffness index Nm/g 104 179 236 Tensile
strength MD, dry N/m 3126 3061 1499 Tensile strength CD, dry N/m
672 745 630 Tensile Index, dry Nm/g 19 17 12 Stretch MD % 28 33 13
Stretch CD % 71 45 44 Stretch sq root (MDCD) % 45 39 24 Work to
rupture MD J/m.sup.2 647 714 251 Work to rupture CD J/m.sup.2 347
238 261 Work to rupture index J/g 6 5 3 Tensile strength MD, water
N/m 2066 3028 568 Tensile strength CD, water N/m 330 619 185
Tensile index, water Nm/g 10.8 15.6 3.9 Relative strength, water %
57 91 33 Tensile str. MD, surfactant N/m 1536 3002 407 Tensile str.
CD, surfactant N/m 330 647 122 Tensile index, surfactant Nm/g 9.3
18.2 2.5 Rel strength, surfactant % 49 96 15 Absorption DIN, water
g/g 6.0 5.1 3.9 Absorption speed WAT, x-dir. s/m 0.4 0.7 1.7 (CD)
Absorption speed WAT, y-dir. s/m 0.8 1.3 2.7 (MD) Wet linting
part./m.sup.2 397 228 259
[0065] The tensile stiffness, tensile strength, work to rupture and
stretch were measured according to the test method SCAN-P44:81.
[0066] The absorption DIN was measured according to the test method
DIN 54 540, part 4, with the modification that the sample was
suspended vertically during soaking and not in horizontal position
as in the standard method.
[0067] The absorption speed WAT was measured according to the test
method SCAN-P 62:88. However the following modification of the
sample was made: Instead of aiming for a total grammage of between
100 and 150 g/m.sup.2 of the sample sheaf, we have aimed for a
total thickness of 1 mm. No measurements of the absorption speed in
z-direction were made.
[0068] These results show superior strength properties both in dry
and wet conditions for the nonwoven materials according to the
invention. This is believed to be due to the strong network that is
created by the man-made fibres present in the material, said
network being more or less continuous. The choice of man-made
fibres also plays an important role for the strength of the
material, and it is seen from the test results that Ex. 2 which
contains 40% by weight polypropylene fibres (1.7 dtex/18 mm), has
improved strength properties as compared to Ex. 1 containing a
mixture of polyester and polypropylene, 25% polyester (1.7 dtex/19
mm) and 17% polypropylene fibres (1.7 dtex/18 mm). However both
materials have considerably higher strengths, i.e. tensile strength
(dry, water, surfactant), stretch and work to rupture, as compared
to the reference material.
[0069] The materials according to the invention are less stiff than
the reference material.
[0070] The materials according to the invention further have
improved absorption properties, both total absorbency and
absorption or wicking speed (WAT), as compared to the reference
material. This is believed to be due to a combination of the high
concentration of pulp fibres present in the plurality of cushions
protruding from one side of the material, said cushions of pulp
fibres being capable of absorbing and holding liquid, and the
network of predominantly man-made fibres, said network being
adapted to distribute the liquid in the material.
* * * * *