U.S. patent application number 13/380095 was filed with the patent office on 2012-04-26 for high barrier nonwoven.
This patent application is currently assigned to FIBERTEX A/S. Invention is credited to Lone Kondrup Hummelgaard, Brian Udengaard.
Application Number | 20120100772 13/380095 |
Document ID | / |
Family ID | 41211869 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120100772 |
Kind Code |
A1 |
Hummelgaard; Lone Kondrup ;
et al. |
April 26, 2012 |
HIGH BARRIER NONWOVEN
Abstract
The present invention relates to a high barrier polymer
nonwoven, characterized in that the surface tension of the polymer
material is decreased by the use of esters of carboxylic acids as a
melt-additive. As a result of the decrease in surface energy the
presented nonwoven fabrics show excellent properties with regard to
low per-meability towards low surface tension liquids, such as for
example running bowel movement or alcohol, in hygiene applications.
The properties are achieved without the use of fluorine-based
chemicals or silicone coating, both of which represent the state of
the art to impart the properties presented to polymer nonwoven
fabrics.
Inventors: |
Hummelgaard; Lone Kondrup;
(Aalborg, DK) ; Udengaard; Brian; (Lystrup,
DK) |
Assignee: |
FIBERTEX A/S
Aalborg Ost
DK
|
Family ID: |
41211869 |
Appl. No.: |
13/380095 |
Filed: |
April 23, 2010 |
PCT Filed: |
April 23, 2010 |
PCT NO: |
PCT/EP2010/002530 |
371 Date: |
December 22, 2011 |
Current U.S.
Class: |
442/327 |
Current CPC
Class: |
D04H 13/00 20130101;
D04H 3/033 20130101; B32B 5/22 20130101; D04H 3/14 20130101; B32B
2262/0253 20130101; C08K 5/103 20130101; D04H 3/007 20130101; Y10T
442/60 20150401; B32B 2307/7265 20130101; B32B 2535/00 20130101;
B32B 2262/12 20130101; B32B 2555/00 20130101; D04H 3/16 20130101;
B32B 2307/50 20130101; B32B 5/022 20130101; B32B 2250/20 20130101;
B32B 2432/00 20130101; B32B 2307/75 20130101; B32B 2555/02
20130101; B32B 5/26 20130101; B32B 5/08 20130101; B32B 2307/726
20130101 |
Class at
Publication: |
442/327 |
International
Class: |
D04H 13/00 20060101
D04H013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 2009 |
EP |
09008335.3 |
Claims
1. A nonwoven web or nonwoven layer made of fibers, obtainable from
a mixture of one or more thermoplastic polymers and an additive
component, characterized by the additive component comprising one
or more lipid esters.
2. Nonwoven web or nonwoven layer as of claim 1, whereby the
additive component is a melt additive.
3. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the additive component comprises a
triglyceride.
4. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the additive component comprises glycerol
tristearate.
5. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the thermoplastic polymer(s) comprise isotactic
thermoplastic polymers.
6. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the thermoplastic polymer(s) comprise
polypropylene.
7. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the thermoplastic polymer(s) comprise polypropylene
synthesized with a metallocene catalyst.
8. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the nonwoven is a thermally bonded, layered fabric
of two or more spunbound (S) and/or meltblown (M) polymer
layers.
9. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the spunbound (S) and meltblown (M) polymer layers
are arranged in the order SMMS, SSMMS or SMMMS.
10. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the Low Surface Tension Strike Through (32
mJ/m.sup.2) of the nonwoven is increased by more than 25%.
11. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the Low Surface Tension Strike Through (32
mJ/m.sup.2) of the nonwoven is increased by more than 50%.
12. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the Low Surface Tension Strike Through (32
mJ/m.sup.2) of the nonwoven is increased by more than 100%.
13. Nonwoven web or nonwoven layer as of any of the preceding
claims, whereby the Low Surface Tension Strike Through (32
mJ/m.sup.2) of the nonwoven is increased by more than 200%.
14. Nonwoven web or nonwoven layer as of any of the preceding
claims, additionally comprising a skin care composition and/or an
ink composition.
15. Nonwoven web or nonwoven layer as of any of the preceding
claims, comprising spunbond layer(s) and/or meltblown layer(s),
wherein at least one layer is made of fibers obtainable from a
mixture of 90% to 99.5% by weight of said thermoplastic polyolefin
polymer and from 0.5% to 10% by weight of said additive component.
Description
[0001] The present invention relates to a nonwoven web or nonwoven
layer made of fibers, obtainable from a mixture of one or more
thermoplastic polymers and an additive component.
[0002] Hygiene applications such as baby diapers, feminine hygiene
products, adult incontinence products, wipes, bandages and wound
dressing as well as medical isolation gowns, surgical gowns,
surgical drapes and covers, surgical scrub suits, surgical caps and
other hygiene products such as panty liners or sanitary napkins or
pads are well-known and used on a daily basis.
[0003] In connection with the above mentioned articles the use of
polymer nonwoven fabrics as barrier material for different bodily
fluids, such as, for example urine or other bodily secretions is
common and well-known in the state of the art.
[0004] It is also commonly known that a decrease in pore size as
well as a decrease in fiber diameter is beneficial to the liquid
barrier properties of a nonwoven fabric. Imparting such properties
to a nonwoven fabric has become increasingly common with the
production of melt-blown nonwovens that render an opportunity to
produce nonwoven fabrics with fibers that have extremely fine
diameters. Since meltblown nonwovens have limited tensile strength
they are usually combined with layers of spunbound nonwovens so as
to reinforce the fabric. The resulting two or more layers are e.g.
thermally bonded. Such layer products may be industrially produced
in a continuous process. Common layering patterns include the SMS
pattern, as well as patterns with more layers, such as e.g. SMMS,
SMMMS or SSMMS patterns.
[0005] A further common approach already known from the state of
the art is to increase the barrier properties of a nonwoven fabric
with respect to liquid permeability by increasing the basis weight
of the material. This is the obvious approach, however it is not
very sophisticated since other properties like softness and weight
of the respective products are altered in an unfavourable way.
[0006] It can therefore be concluded that it would be desirable to
alter the properties of the material itself, especially with
respect to manufacturing products with high barrier towards low
surface tension liquids, such as for example running bowel movement
(faeces from newborn babies), since the above mentioned techniques
to increase the liquid barrier of a nonwoven are directed to the
general use, meaning barrier properties towards mainly waterbased
liquids with a relatively high surface tension e.g. urine or
menstrual fluid. They do not show a sufficiently high barrier
towards low surface tension liquids, which means that there is a
higher risk of leakage, for example, from a diaper (a well-known
phenomenon for most parents with infants).
[0007] A potential solution is to develop a material that has a
lower intrinsic surface energy than the commonly used polymers. For
the intended applications, such a lower intrinsic surface energy
results in a significant improvement in low surface tension liquid
strike through.
[0008] Common approaches to lower the surface energy of the
material and thus allow for high values for low surface tension
liquid strike through of a nonwoven fabricated therewith are
silicon coating as well as the use of fluorine chemicals, as
already known from the state of the art. The technique of silicone
coating is for example used in the patent WO 2006/005769, which
describes light-weight nonwoven barrier members that have been
treated with a hydrophobic surface coating (silicone) intended to
render such components impermeable to liquids having a relatively
low surface tension. The main drawback of the use of silicone based
coatings is that it is relatively difficult to employ them in a
continuous production environment due to the extensive difficulties
involved in cleaning after using silicone, as silicone is extremely
difficult to dissolve, meaning that extensive manual labour is
often necessary for cleaning. Also, the use of coatings
necessitates an extra step in the production process, adding
complexity and equipment cost.
[0009] The use of fluorine chemicals is an improvement over
materials made from pure polypropylene with regard to the
achievement of a lower intrinsic surface energy of the material and
thus, for example, an increase in the barrier towards low surface
tension liquids. However, fluorine chemicals are generally frowned
upon in the hygiene industry due to the risk of skin irritations
resulting from the addition of some types of the respective
chemicals, regardless their efficiency in lowering surface energy
and thus in improving low surface tension liquid strike
through.
[0010] From the above it becomes obvious that an optimum solution
for a nonwoven material with excellent barrier properties towards
low surface tension liquids in hygiene applications is yet to be
found. It is, therefore, the goal of the present invention to
tackle one or all of the drawbacks of the state of the art, and/or
minimize the risk of leakage of low surface tension liquids through
barrier sheets of body hygiene applications without using flourine
based chemistry or coated materials, by employing an additive (a
melt additive) which is put into the melt together with polymer
granulate in a continuous process producing a spunbound/meltblown
nonwoven fabric.
[0011] According to the present invention, one or all of these
desirable properties can be achieved by a nonwoven web or nonwoven
layer according to claim 1. Accordingly, the additive component
comprises one or more lipid esters.
[0012] Due to this specific melt additive, a low intrinsic surface
energy can be imparted to polymer material. Consequently, these
melt additives can also impart an improved low surface tension
liquid strike through to nonwovens that are fabricated with such a
material.
[0013] The present invention encompasses a high barrier polymer
nonwoven, characterized in that the surface energy of the polymer
material is decreased by the use of lipid esters as melt additives.
In one preferred embodiment of the invention the lipid esters are
triglycerides, representatives of some common triglycerides being
triglycerides with either one, two, or all three hydroxy functional
groups esterified with the same or different members of e.g. the
group arachidec, stearic, palmitic, myristic, myristoleic, oleic,
linoeic or arachidonic acid, as non-limiting examples, and other
carboxylic acids or combinations thereof.
[0014] In the most preferred embodiment of the invention said
triglyceride is glycerol tristearate (CAS No 555-43-1), also known
by such names as tristearin or 1,2,3-Trioctadecanoylglycerol. In
the following the name glycerol tristearate will be used, and in
case of doubt the CAS No shall be seen as the primary
identifier.
[0015] The lowering of the surface energy of the resulting polymer
by the addition of glycerol tristearate is not obvious because
glycerol tristearate has a surface energy of 34.2 mJ/m.sup.2.
Usually, a reduction in surface tension is achieved by the addition
of chemicals with a lower surface energy than the respective
polymer, e.g. fluorine chemicals. In one embodiment, the addition
of lipid esters, preferably glycerol tristearate does not adversely
effect the spinablity of the fibers on a spunmelt line (at a
concentration of up to 10%) and the addition of an additive is
simple and elegant, not demanding extra steps in the production
process as opposed to e.g. a coating procedure.
[0016] Table 1 summarizes the surface energy of some common
polymers.
TABLE-US-00001 TABLE 1 Polymer type Surface Energy Isotactic
polypropylene 29.4 mJ/m.sup.2 (20.degree. C.) Atactic polypropylene
29.4 mJ/m.sup.2 (20.degree. C.) Mixture of isotactic and atactic
polypropylene 30.1 mJ/m.sup.2 (20.degree. C.) Linear polyethylene
(M.sub.w = 67000) 35.7 mJ/m.sup.2 (20.degree. C.) Branched
polyethylene (M.sub.n = 7000) 35.3 mJ/m.sup.2 (20.degree. C.)
Branched polyethylene (M.sub.n = 2000) 33.3 mJ/m.sup.2 (20.degree.
C.) Poly(ethylene terephthalate) (M.sub.n = 16000, 44.6 mJ/m.sup.2
(20.degree. C.) M.sub.w = 37000) Source: Brandrup, Immergut, Grulke
(Editors), Polymer Handbook 4.sup.th edition, Wiley-Interscience,
New York, 1999.
[0017] The fibers can be made of thermoplastic polymers, including
polymer compositions, mixtures and blends. Examples of suitable
thermoplastic polymers for the use herein include polyolefins,
preferably polypropylene or polyethylene or
polyethyl-ene-polypropylene copolymers; polyesters, polyamides;
polyhydroxyalkanoates, and mixtures thereof. Other suitable
thermoplastic polymers include i.a. biodegradable polymers such as
PHAs, PLAs or starch compositions.
[0018] The fibres may also be multicomponent fibres, including
bicomponent fibres; a bi-component fibre may be in a side-by-side,
sheath-core, segmented pie, ribbon, or islands-in-the-sea
configuration. The sheath may be continuous or non-continuous
around the core. The sheath may comprise polypropylene. In one
embodiment, polypropylene and polypropylene compositions are
preferred, including homopolymers of propylene, copolymers of
propylene, such as, for example, block, graft, random and
alternating copolymers, terpolymers, etc., and blends and
modifications thereof; polypropylene homopolymers, and copolymers
of propylene with ethylene and/or butane may be suitably used, and
polypropylene. In one embodiment, the polymers to be mixed with the
additive are polymers that are not or hardly elastic.
[0019] The barrier sheet may comprise one or more nonwoven webs or
layers made of fibers that do not comprise said additive. Such
nonwoven webs and layers may be made of the thermoplastic polymers
described above, and with the processes described above.
[0020] The fibres of one or more of the webs or layers herein may
be nanofibers, with a diameter of less than 1000 nanometers. A
layer or web may consist exclusively of nanofibers, or it may be
mixed with fibers of a larger diameter. Alternatively, or in
addition, the spunbond web or layer herein may for example have
spunbond fibers with a number average fiber diameter of, for
example, from 6 to 22 microns, or from 10 to 18 microns, or from 10
microns or 11 microns to 15 microns or to 14 microns. The meltblown
web or layer herein may for example have meltblown fibers that have
a number average fiber diameter from 1 to 5 microns, or 1 to 4
microns, or preferably from 1 to 3 microns.
[0021] One preferred polymer material is polypropylene linked with
the help of a metallocene catalyst. Such metallocene-polypropylene
polymers offer a much greater level of control than conservative
polypropylene materials that are connected with the help of a
Ziegler-Natta catalyst, because the metallocene molecules offer
better control towards how the monomers are linked, so that a
proper choice of catalysts can produce isotactic, syndiotactic or
atactic polypropylene, or even a combination of these. Further
still, they can also produce polypropylene materials with a much
narrower molecular weight distribution than traditional
Ziegler-Natta catalysts, which can further improve properties,
especially in that the narrower molecular weight distribution
allows a higher draw ratio, thus allowing thinner fibers to be
spun.
[0022] In one preferred embodiment of the invention the high
barrier nonwoven is manufactured by spunbound/meltblown layering.
The use of the above mentioned polypropylene material is
particularly useful for the production of nonwovens employing this
technique because, as already mentioned, it allows thinner fibers
to be spun. Furthermore, the additive has a lubricating effect in
the extruder, which has a positive effect on processing conditions
and stability. The highest effect of adding glycerol tristearate
has been achieved in an SMMMS spunmelt, because the allowance for
thinner spunbound fibers works in synergy with a second effect,
being that three of these thin meltblown fibers are contained in an
SMMMS spunmelt (MMM), as opposed to two meltblown beams (MM) as in
an SMMS or SSMMS spunmelt. Employing three meltblown beams allows
each of them to run at a lower throughput to obtain the same
coverage (grams per m.sup.2). Thinner and more meltblown fibers
result in a lower pore size of the nonwoven and a higher surface
area of the fibers. A low pore size makes it more difficult for a
liquid to penetrate the material and, as the additive blooms to the
surface and is active with the surface, a high surface area of the
fibers increases the effect of the melt additive.
[0023] The above mentioned facts render the advantages to use
polymer layers in an SMMMS configuration. However, our invention
also contemplates the use of other types of configurations like
SMMS, SSMMS, and other configurations known to the skilled person.
Nonwovens according to the present invention comprise at least one
spunbound (S) or meltblown (M) polymer layer that is made of fibers
comprising both said polymer material and said melt additive. In
one embodiment, these fibers are obtainable from a mixture of the
polymer material and the melt additive in their molten form. In a
specific embodiment of the invention the nonwoven comprises at
least one spunbound (S) or meltblown (M) polymer layer that is made
of fibers comprising 90% w/w to 99.9% w/w of said polymer material
and 0.1% w/w to 10% w/w of said melt additive, preferably 90% w/w
to 99.5% w/w of said polymer material and 0.5% w/w to 10% w/w of
said melt additive.
[0024] After spinning fibers, the additive can be present
throughout their length and diameter (e.g. from the center to the
surface). However, in one embodiment, the additive is present in a
higher concentration at the surface than in the centre of the
fibers. In one embodiment, the nonwoven web or barrier sheet or
barrier component, comprising said fibers is heated by a heat
source or radiated, or compressed, for example by nip rollers,
during or after web formation, (e.g. in order to obtain this
concentration gradient). This can be done across the whole width of
the nonwoven barrier sheet or in specific lanes, zones or regions
(herein referred to as regions). This can be done by the use of
zoned compression rollers with varying diameters and nip gaps or
pressures, or with heat zones in form of hot, profiled nip rollers,
or infra-red heat sources, or other lanes or alternating regions of
radiating energy. These deliberate activation steps can be employed
during the nonwoven web production, or during the nonwoven barrier
sheet production, or during storage or packaged transportation
thereof, or during further processing thereof into a barrier
component, or during final production of the absorbent article.
Thus, in one embodiment the invention relates to absorbent articles
with barrier components comprising a nonwoven barrier sheet,
comprising a nonwoven web or layer of fibers, obtainable of a
mixture of said thermoplastic polymers and said additive, whereby
the fibers in one region of said layer or web have a higher
concentration of additive on the surface of said fibers than in
another region, said region being typically at least 1 mm.sup.2;
said concentration difference being for example at least 10%, or at
least 20% or at least 30%.
[0025] The present invention comprises, in one embodiment, nonwoven
barrier sheets and/or barrier components that may have a pore size
of less than 60 .mu.m, preferably less than 50 .mu.m, even more
preferably less than 45 .mu.m, but at least 1 .mu.m, preferably at
least 2 .mu.m. In one preferred embodiment, the nonwoven barrier
sheet and/or barrier component has a narrow pore size distribution.
The nonwoven barrier sheet and/or barrier component may have pores
of a mean flow pore size within the range of from 1 to 30 .mu.m,
and preferably from 5 to 20 .mu.m.
[0026] A representative spunmelt nonwoven fabric made of standard
polypropylene with an area weight of about 22 g/m.sup.2, as will be
exemplified hereinafter, can for example have have a low surface
tension liquid strike through (32 mJ/m.sup.2) of around 16 seconds
(SMMS) or 26 seconds (SMMMS). The nonwoven barrier sheet and/or
barrier component according to the present invention has in one
embodiment a surface tension strike through value, as determined by
the method described herein for a liquid of 32 mN/m surface
tension, which has been increased by at least about 25% preferably
by about 50%, even more preferably by more than about 100%, and
yeteven more preferably by more than about 200%. The surface
tension strike-through value may be limited optionally to less than
200 seconds, or less than 150 seconds or less than 100 seconds. A
nonwoven barrier sheet or barrier component is considered to have
the above low surface tension strike through values if it has this
value at any part of the material, excluding areas comprising
elastic material or edges being attached to other materials.
[0027] The very favourable properties with regard to low surface
tension strike through, which can be seen in the examples and
results, can be achieved without the addition of any fluorine based
melt additives or any other fluorine based chemicals. Also, the
present invention does not necessitate the coating of the material
with silicone based materials or any other materials. However, the
skilled person will be aware that the concerted use of the elements
of the present invention with any of these processes may impart
even lower surface energy to the material.
[0028] In one embodiment, the resulting high barrier polymer
nonwoven shows an improved low surface tension liquid strike
through, or in other words an increased barrier towards low surface
tension liquids. The solution presented in the method above is
convenient in terms of fabrication in comparison to silicone
coating, as an additional coating step, additional equipment, or
extra cleaning can be avoided. The additive does not contain
fluorine, thus allowing to obtain the necessary reductions in
surface energy to contain, for example, runny bowl movement without
the use of questionable chemistry.
[0029] Besides lowering the surface energy and improving the low
surface tension liquid strike through times of the spunmelt
polypropylene nonwoven, some additional advantages can be imparted
by the additives of the present invention. The nonwoven can become
more drapeable and smooth due to the addition of the melt-additive
described above, which in turn can lead to an improvement in
perceived softness (this has been tested objectively using the
Handle-O-Meter test method). Furthermore, the additive can have a
lubricating effect in the extruder, which can have a positive
effect on processing conditions and stability.
[0030] The barrier component may be used as an integral part to
absorbent articles, and in one specific embodiment to absorbent
hygiene articles. The absorbent hygiene article herein is
preferably a panty liner or a sanitary napkin or pad, a baby
diaper, a feminine hygiene product, an adult incontinence product,
a wipe, a bandage or wound dressing, a medical isolation gown,
surgical gown, surgical drape or cover, a surgical scrub suit or
cap.
[0031] In one embodiment, the barrier component additionally
comprises an ink composition, typically applied in a pattern,
and/or in the form of figure(s) and/or letter(s), for example by
printing. The ink composition may be an aqueous composition. This
can be applied to barrier nonwovens sheet or barrier component
despite the presence of fibers on the surface and despite the
barrier nature and typically (e.g. hydrophobic) nature of these
barrier components and nonwoven barrier sheets herein.
[0032] In one embodiment herein the barrier component may comprise
a skin care composition, also referred to in the art as lotion or
lotion composition. A portion of, or an entire surface of the
barrier component may comprise on its surface (e.g. may be coated
with) a skin care composition. Preferred may be that said barrier
component comprises said skin care composition (or lotion) at least
on the elasticated portions, described above, if present.
[0033] Test Methods:
[0034] Basis Weight:
[0035] The basis weight herein can be measured consistent with ASTM
D 756, ISO 536 and EDANA ERT-40.3-90. It is defined as mass per
unit area, in g/m.sup.2 (also referred to gsm), and measured on the
component or sheet as a whole, if possible with this method, or a
sample thereof; the total sample surface area may be any size
suitable for the test method, but preferably a sample of 100
cm.sup.2 (.+-.0.5%) is used. The sample is conditioned at
23.degree. Celsius (.+-.2.degree. C.) and at a relative humidity of
50% for 2 hours to reach equilibrium, prior to weight
determination.
[0036] Fiber Diameter:
[0037] The number average fiber diameters herein are determined by
using a Scanning Electron Microscope (SEM) and its image analysis
software. A magnification is chosen such that the fibers are
suitably enlarged for measurements, e.g. between 1000 and 10,000.
At least 100 fibers are measured, and the number average fiber
diameter is calculated with the software and used herein.
[0038] Maximum (Largest) Pore Size and Mean Flow Pore Size
Determination:
[0039] The maximum pore size and mean flow pore size as used herein
can be measured with a PMI Porometer in accordance with ASTM
E1294-89 and F316-89 methods (capillary Constant as per ASTM method
is 1; wetting fluid is Galwick, with Surface Tension of 15.9 mN/m;
the surface tension of this fluid can be determined as set out
herein below).
[0040] As Porometer, a PMI Capillary Flow Porometry, model
CFP-1200-AEX, may suitably be used.
[0041] A wrinkle free, clean circular sample is obtained from the
barrier component (which is free in the sample area of elastic
material or film material, as described herein) or nonwoven barrier
sheet (depending on which value needs to be tested in accord with
the invention), having a diameter of 1.0 cm (conditioned for 2
hours at 20.degree. C., 50% relative humidity). Using tweezers, the
sample is immersed the in petri dish filled with the Galwick 15.9
mN/m wetting fluid such that the fluid completely covers the
sample, for 30 seconds. Then the sample is turned, using tweezers,
and reimmersed in the same dish and fluid, for a further 30
seconds. This ensures complete saturation of the pores with the
wetting fluid.
[0042] Then, using tweezers, the saturated sample is directly
placed onto the O-ring of the lower sample adaptor, without
allowing the wetting fluid to drain, ensuring that that the O-ring
is completely covered by the sample, but without covering the gauze
during placement of the sample.
[0043] With the O-ring and sample facing upwards on the lower
adopter and facing the upper adaptor, the Porometer is further
prepared as per its manual and the measurement is started according
to manual. The apparatus' software will analyse the measurements
and report the maximum pore size as used herein. It will also
calculate the mean flow pore size.
[0044] Handle-O-Meter Stiffness
[0045] The Handle-O-Meter Stiffness was measured according to the
standard test method WSP 90.3.0 (05).
[0046] Alcohol Repellency
[0047] Alcohol Repllency (AR) was measured by INDA IST 80.8.
[0048] INDA IST 80.8. is a standard test method for measuring the
resistance of nonwoven fabrics to penetration by aqueous
isopropanol solutions. The alcohol repellency was reported in
ratings based upon alcohol concentrations. The highest number of
test solutions that did not penetrate the tested fabric within five
minutes was recorded.
[0049] Low Surface Tension Strike Through (LST. ST) Value
Method
[0050] The low surface tension strike through value referred to
herein may be obtained by the Edana method WSP70.3 (05), except
that a low surface tension liquid (see below) is used and a sample
of 1 inch.times.1 inch (25 mm.times.25 mm) may be used. The sample
should be free of elastic material or of edges that are connected
to other materials.
[0051] The value obtained from this sample measurement is reported
herein.
[0052] The low surface tension liquid is a liquid with a surface
tension of 32 mN/m prepared as follows:
[0053] In a clean flask, 2.100 grams of Triton-X-100 is added to
500 ml distilled water (already in flask) and then 5000 ml
distilled water is added. The solution is mixed for 30 minutes and
then the surface tension is measured, which should be 32 mN/m.
[0054] (The surface tension may be determined by method: ASTM
D1331-56 ("Standard test method for surface and interfacial tension
of solution of surface active agents") using a Kruss K12
tensiometer.)
[0055] The following examples and figures are set forth for the
purpose of illustrating our invention in more detail.
FIGURES
[0056] FIG. 1 is a graphical representation of the alcohol
repellency of comparative example 1 and examples 1 through 5.
[0057] FIGS. 2 and 3 are graphical representations of the liquid
strike through (32 mJ/m.sup.2) in seconds for comparative example 1
and examples 1 through 5. The LST is shown depending on the
percentual values for active ingredient in the respective examples.
FIG. 2 also indicates the percentual increase in LST as compared to
comparative example 1.
[0058] FIG. 4 is a graphical representation of the handle-o-meter
stiffness [g] of comparative example 1 and examples 1 through
5.
[0059] FIGS. 5 and 6 are graphical representations of the liquid
strike through (32 mJ/m.sup.2) in seconds for comparative example 2
and examples 6 through 8. The LST is shown depending on the
percentual values for active ingredient in the respective examples.
FIG. 5 also indicates the percentual increase in LST as compared to
comparative example 2.
[0060] FIGS. 7 and 8 are graphical representations of the liquid
strike through (32 mJ/m.sup.2) in seconds for comparative example 3
and examples 9 through 12. The LST is shown depending on the
percentual values for active ingredient in the respective examples.
FIG. 7 also indicates the percentual increase in LST as compared to
comparative example 3.
[0061] FIGS. 9 and 10 are graphical representations of the liquid
strike through (32 mJ/m.sup.2) in seconds for comparative example 4
and examples 13 through 16. The LST is shown depending on the
percentual values for active ingredient in the respective examples.
FIG. 9 also indicates the percentual increase in LST as compared to
comparative example 4.
[0062] FIGS. 11 and 12 are graphical representations of the liquid
strike through (32 mJ/m.sup.2) in seconds for comparative example 5
and examples 17 and 18. The LST is shown depending on the
percentual values for active ingredient in the respective examples.
FIG. 11 also indicates the percentual increase in LST as compared
to comparative example 5.
EXAMPLES
[0063] Comparative Examples 1 to 5 aim to illustrate the state of
the art in comparison to Examples 1 to 19, which aim to illustrate
the properties of the nonwoven that can be achieved by using the
method disclosed in the present invention.
Comparative Example 1
[0064] An SMMS multilayer nonwoven was produced from Ziegler-Natta
polypropylene in a continuous production on a 4.5 m wide
Reifenhe,uml aee user Reicofil 3 SMMS line. Each layer of S-layers
had a weight of 9.5 g/m.sup.2 and each of the M layers had a weight
of 1.5 g/m.sup.2, resulting in a thermally bonded SMMS layered
nonwoven product having a total weight per area of 22
g/m.sup.2.
[0065] In each of the following five Examples the single layers of
the SMMS sheet will be denoted as indicated in parentheses:
S(1)M(2)M(3)S(4).
Example 1
[0066] A layered fabric was produced following the process
described in Comparative Example 1, where the polymer forming Layer
4 contained 0.8% w/w of glycerol tristearate as an additive
component, hereinafter referred to as "active ingredient",
resulting in an average weight percentage of 0.3% w/w of active
ingredient in the total fabric.
Example 2
[0067] A layered fabric was produced as described in Example 1,
where the polymer forming each of the Layers 1 and 4 contained 0.8%
w/w of active ingredient, resulting in an average weight percentage
of 0.7% w/w of active ingredient in the total fabric.
Example 3
[0068] A layered fabric was produced as described in Example 1,
where the polymer forming each of the Layers 1 and 4 contained 1.6%
w/w of active ingredient, resulting in an average weight percentage
of 1.4% w/w of active ingredient in the total fabric.
Example 4
[0069] A layered fabric was produced as described in Example 1,
where the polymer forming each of the layers 1 and 4 contained 2.4%
w/w of active ingredient, resulting in an average weight percentage
of 2.1% w/w of active ingredient in the total fabric.
Example 5
[0070] A layered fabric was produced according to Example 1, where
the polymer forming each of the Layers 1, 2 and 4 contained 2.4%
w/w of active ingredient, resulting in an average weight percentage
of 2.2% w/w of active ingredient in the total fabric.
[0071] The contents of active ingredient of Comparative Example 1
as well as of Examples 1 through 5 are summarized in Table 2.
TABLE-US-00002 TABLE 2 Lay-up [g] Configuration S M M S SMMS 9.5
1.5 1.5 9.5 22 g Example Active ingredient per beam [%] Average [%]
C1 0 0 0 0 0.0 1 0 0 0 0.8 0.3 2 0.8 0 0 0.8 0.7 3 1.6 0 0 1.6 1.4
4 2.4 0 0 2.4 2.1 5 2.4 2.4 0 2.4 2.2
[0072] The following tests were carried out according to the
methods introduced in the section "Test Methods" to assess the
Alcohol Repellency Properties, the Strike Through (32 mJ/m.sup.2)
Properties, the Handle-O-Meter CD (cross-directional) Stiffness and
the Handle-O-Meter MD (machine-directional) Stiffness. The
corresponding results are summarized in Tables 3 to 6 and FIGS. 1
to 4.
[0073] The Alcohol Repellency was measured for Comparative Example
1 as well as Examples 1 to 5 and the results are shown in Table 3
and FIG. 1.
TABLE-US-00003 TABLE 3 Alcohol Repellency Example C1 1 2 3 4 5 3 4
5 5 5 6 3 4 6 5 5 6 3 4 5 5 6 6 3 4 5 6 5 6 3 4 6 5 6 6 Resulting 3
4 5 5 5 6
[0074] The strike through (32 mJ/m.sup.2) was measured for
Comparative Example 1 as well as Examples 1 to 5 and the results
are shown in Table 4 and FIGS. 2 and 3.
TABLE-US-00004 TABLE 4 Example C1 1 2 3 4 5 Strike through 16.04
24.72 26.25 29.41 36.51 44.14 (32 mJ/m.sup.2) [s] Increase of LST 0
54 64 83 128 175 ST [%]
[0075] The Handle-O-Meter CD-Stiffness as well as the
Handle-O-Meter MD-Stiffness were measured for Comparative Example 1
as well as for Examples 1 to 5 and the respective values are given
in Tables 5 and 6 as well as FIG. 4.
TABLE-US-00005 TABLE 5 Handle-o-Meter CD-stiffness [g] Example C1 1
2 3 4 5 7.9 6.6 6.0 5.0 5.1 4.9 8.7 5.9 5.0 5.5 4.4 4.8 7.3 6.0 5.4
5.0 4.9 5.1 8.1 6.0 5.3 4.6 4.9 5.0 5.9 6.1 4.4 5.3 5.1 4.0 Average
7.6 6.1 5.2 5.1 4.9 4.8 Std dev 1.1 0.3 0.6 0.3 0.3 0.4 Min 5.9 5.9
4.4 4.6 4.4 4.0 Max 8.7 6.6 6.0 5.5 5.1 5.1
TABLE-US-00006 TABLE 6 Handle-o-Meter MD-stiffness [g] Example C1 1
2 3 4 5 11.6 10.4 9 10.1 9.9 8.7 13.9 11.0 8.8 9.9 8 9.6 12.3 10.9
10 7.9 8.7 8.8 13.3 10.7 10 9.3 9.1 8.2 11.9 10.8 10.8 8.6 8.5 8.0
Average 12.6 10.8 9.7 9.2 8.8 8.7 Std dev 1.0 0.2 0.8 0.9 0.7 0.6
Min 11.6 10.4 8.8 7.9 8.0 8.0 Max 13.9 11.0 10.8 10.1 9.9 9.6
Comparative Example 2
[0076] An SMMMS multilayer nonwoven was produced from
metallocene-polypropylene in a continuous production on a 4.5 m
wide Reifenhauser Reicofil 4 SMMMS line. Each layer of S-layers had
a weight of 9.5 g/m.sup.2 and each of the M layers had a weight of
1.0 g/m.sup.2, resulting in a thermally bonded SMMMS layered
nonwoven product having a total weight per area of 22
g/m.sup.2.
[0077] In each of the following three Examples, the single layers
of the SMMMS sheet will be denoted as indicated in parentheses:
S(1)M(2)M(3)M(4)S(5).
Example 6
[0078] A layered fabric was produced following the process
described in Comparative Example 2, where the polymers forming
Layers 2, 3 and 4 contained 2.3% w/w of active ingredient,
resulting in an average weight percentage of 0.3% w/w of active
ingredient in the total fabric.
Example 7
[0079] A layered fabric was produced as described in Example 6,
where the polymers forming each of the Layers 2, 3 and 4 contained
2.3% w/w and the one forming Layer 5 contained 2.0% w/w of active
ingredent of active ingredient, resulting in an average weight
percentage of 1.2% w/w of active ingredient in the total
fabric.
Example 8
[0080] A layered fabric was produced as described in Example 6,
where the polymers forming each of the Layers 2, 3 and 4 contained
2.3% w/w, and the one forming Layer 5 contained 3.0% w/w of active
ingredient, resulting in an average weight percentage of 1.6% w/w
of active ingredient in the total fabric.
[0081] The content of active ingredient of Comparative Example 2 as
well as Examples 6 through 8 are summarized in Table 7.
TABLE-US-00007 TABLE 7 Lay-up [g] Configuration S M M M S SMMMS 9.5
1 1 1 9.5 22 g Example Active ingredient per beam [%] Average [%]
C2 0.0 0.0 0.0 0.0 0.0 0.0 6 0.0 2.3 2.3 2.3 0.0 0.3 7 0.0 2.3 2.3
2.3 2.0 1.2 8 0.0 2.3 2.3 2.3 3.0 1.6
[0082] The following tests were carried out according to the method
introduced in the section "Test Methods" to assess the Strike
Through (32 mJ/m.sup.2) Properties. The Strike Through (32
mJ/m.sup.2) was measured for Comparative Example 2 as well as
Examples 6 to 8 and the results are shown in Table 8 and FIGS. 5 to
6.
TABLE-US-00008 TABLE 8 Example C2 6 7 8 Strike through (32
mJ/m.sup.2) [s] 25.59 42.42 64.57 79.17 Increase of LST ST [%] 0 66
152 209
Comparative Example 3
[0083] An SMMS multilayer nonwoven was produced from Ziegler-Natta
polypropylene in a continuous production on a 4.5 m wide
Reifenhauser Reicofil 3 SMMS line. Each lay-up of S-layers had a
weight of 6.9 g/m.sup.2 and each of the M layers had a weight of
0.6 g/m.sup.2, resulting in a thermally bonded SMMS layered
nonwoven product having a total weight per area of 15
g/m.sup.2.
[0084] In each of the following four Examples the single layers of
the SMMS sheet will be denoted as indicated in parentheses:
S(1)M(2)M(3)S(4).
Example 9
[0085] A layered fabric was produced as described in Comparative
Example 3, where the polymers forming each of the Layers 2 and 3
contained 7.6% w/w and the one forming Layer 4 contained 2.3% w/w
of active ingredent, resulting in an average weight percentage of
1.7% w/w of active ingredient in the total fabric.
Example 10
[0086] A layered fabric was produced as described in Example 9,
where the polymers forming each of the Layers 2, and 3 contained
2.5% w/w and the one forming Layer 4 contained 3.4% w/w of active
ingredent, resulting in an average weight percentage of 1.8% w/w of
active ingredient in the total fabric.
Example 11
[0087] A layered fabric was produced as described in Example 9,
where the polymers forming Layer 1 contained 6.0% and the one
forming Layers 2, and 3 contained 7.6% w/w and the one forming
Layer 4 contained 6.0% w/w of active ingredent, resulting in an
average weight percentage of 6.1% w/w of active ingredient in the
total fabric.
Example 12
[0088] A layered fabric was produced as described in Example 9,
where the polymers forming Layer 4 contained 4.1% of active
ingredent, resulting in an average weight percentage of 1.9% w/w of
active ingredient in the total fabric.
[0089] The active ingredient contents of Comparative Example 3 as
well as of Examples 9 through 12 are summarized in Table 9.
TABLE-US-00009 TABLE 9 Lay-up [g] Configuration S M M S SMMS 6.9
0.6 0.6 6.9 15 g Example Active ingredient per beam [%] Average [%]
C3 0.0 0.0 0.0 0.0 0.0 9 0.0 7.6 7.6 2.3 1.7 10 0.0 2.5 2.5 3.4 1.8
11 6.0 7.6 7.6 6.0 6.1 12 0.0 0.0 0.0 4.1 1.9
[0090] The Strike Through test was carried out according to the
methods introduced in the section "Test Methods" to assess the
Strike Through (32 mJ/m.sup.2) Properties. The corresponding
results for Comparative Example 3 as well as Examples 9 to 12 are
summarized in Table 10 and FIGS. 7 and 8.
TABLE-US-00010 TABLE 10 Example C3 9 10 11 12 Strike through (32
mJ/m.sup.2) [s] 5.52 7.69 17.42 20.93 16.62 Increase of LST ST [%]
0 39 216 201 279
Comparative Example 4
[0091] An SMMMS multilayer nonwoven was produced from Ziegler-Natta
polypropylene in a continuous production on a 4.5 m wide
Reifenhauser Reicofil 4 SMMMS line. Each lay-up of S-layers had a
weight of 6.3 g/m.sup.2 and each of the M layers had a weight of
0.8 g/m.sup.2, resulting in a thermally bonded SMMMS layered
nonwoven product having a total weight per area of 15
g/m.sup.2.
[0092] In each of the following four Examples the single layers of
the SMMS sheet will be denoted as indicated in parentheses:
S(1)M(2)M(3)M(4)S(5).
Example 13
[0093] A layered fabric was produced as described in Comparative
Example 4, where the polymers forming each of the Layers 2, 3 and 4
contained 1.2% w/w and the one forming Layer 5 contained 1.9% w/w
of active ingredent, resulting in an average weight percentage of
1.0% w/w of active ingredient in the total fabric.
Example 14
[0094] A layered fabric was produced as described in Example 13,
where the polymers forming each of the Layers 2, 3 and 4 contained
2.4% w/w and the one forming Layer 5 contained 1.9% w/w of active
ingredent, resulting in an average weight percentage of 1.2% w/w of
active ingredient in the total fabric.
Example 15
[0095] A layered fabric was produced as described in Example 13,
where the polymers forming each of the Layers 2, 3 and 4 contained
2.4% w/w and the one forming Layer 5 contained 3.0% w/w of active
ingredent, resulting in an average weight percentage of 1.6% w/w of
active ingredient in the total fabric.
Example 16
[0096] A layered fabric was produced as described in Example 13,
where the polymers forming each of the Layers 2, 3 and 4 contained
2.4% w/w and the one forming Layer 5 contained 3.8% w/w of active
ingredent, resulting in an average weight percentage of 2.0% w/w of
active ingredient in the total fabric.
[0097] The active ingredient contents of Comparative Example 4 as
well as of Examples 13 through 16 is summarized in Table 11.
TABLE-US-00011 TABLE 11 Lay-up [g] Configuration S M M M S SMMMS
6.3 0.8 0.8 0.8 6.3 15 g Example Active ingredient per beam [%]
Average [%] C4 0.0 0.0 0.0 0.0 0.0 0.0 13 0 1.2 1.2 1.2 1.9 1.0 14
0 2.4 2.4 2.4 1.9 1.2 15 0 2.4 2.4 2.4 3.0 1.6 16 0.0 2.4 2.4 2.4
3.8 2.0
[0098] The Strike Through test was carried out according to the
methods introduced in the section "Test Methods" to assess the
Strike Through (32 mJ/m.sup.2) Properties. The corresponding
results for Comparative Example 4 as well as Examples 13 to 16 are
summarized in Table 12 and FIGS. 9 and 10.
TABLE-US-00012 TABLE 12 Example C4 13 14 15 16 Strike through (32
mJ/m.sup.2) [s] 9.12 10.75 17.33 25.01 28.05 Increase of LST ST [%]
0 18 90 174 208
Comparative Example 5
[0099] An SMMMS multilayer nonwoven was produced from
metallocene-polypropylene in a continuous production on a 4.5 m
wide Reifenhauser Reicofil 4 SMMMS line. Each layer of S-layers had
a weight of 6.5 g/m.sup.2 and each of the M layers had a weight of
1.3 g/m.sup.2, resulting in a thermally bonded SMMMS layered
nonwoven product having a total weight per area of 17
g/m.sup.2.
[0100] In each of the following two Examples, the single layers of
the SMMMS sheet will be denoted as indicated in parentheses:
S(1)M(2)M(3)M(4)S(5).
Example 17
[0101] A layered fabric was produced as described in Comparative
Example 5, where the polymers forming each of the Layers 2, 3 and 4
contained 2.9% w/w and the one forming Layer 5 contained 3.5% w/w
of active ingredent of active ingredient, resulting in an average
weight percentage of 2.0% w/w of active ingredient in the total
fabric.
Example 18
[0102] A layered fabric was produced as described in Example 17,
where the polymers forming each of the Layers 2, 3 and 4 contained
3.9% w/w, and the one forming Layer 5 contained 4.8% w/w of active
ingredient, resulting in an average weight percentage of 2.7% w/w
of active ingredient in the total fabric.
[0103] The content of active ingredient of Comparative Example 5 as
well as Examples 17 through 18 are summarized in Table 13.
TABLE-US-00013 TABLE 13 Lay-up [g] Configuration S M M M S SMMMS
6.5 1.3 1.3 1.3 6.5 17 g Example Active ingredient per beam [%]
Average [%] C5 0.0 0.0 0.0 0.0 0.0 0.0 17 0.0 2.9 2.9 2.9 3.5 2.0
18 0.0 3.9 3.9 3.9 4.8 2.7
[0104] The Strike Through test was carried out according to the
methods introduced in the section "Test Methods" to assess the
Strike Through (32 mJ/m.sup.2) Properties. The corresponding
results for Comparative Example 5 as well as Examples 17 to 18 are
summarized in Table 14 and FIGS. 11 to 12.
TABLE-US-00014 TABLE 14 Example C5 17 18 Strike through (32
mJ/m.sup.2) [s] 18.53 53.50 58.24 Increase of LST ST [%] 0 189
214
[0105] As laid out in tables 4, 8, 10, 12 and14 and shown in FIGS.
2, 5, 7, 9 and 11, the nonwoven fabrics according to the present
invention show a percentual increase in LST of more than 25%, in
most cases more than 50%, in some cases more than 100% and in some
cases even more than 200% as compared to fabrics without the
additive component according to claim 1, for both SMMS and SMMMS
layered fabrics with differend area weights. As such, a nonwoven
fabric according to the present invention can have twice or even
three times the LST as compared to fabrics without the additive
component according to claim 1.
* * * * *