Note: Descriptions are shown in the official language in which they were submitted.
CA 02352864 2001-07-11
HIGH VOLUME NON-WOVEN
FIELD OF THE INVENTION
The invention relates to non-wovens and in particular to high volume non-
wovens.
BACKGROUND ART
Non-woven sheets with a surface weight of about 25-50 g/m2 are known from the
reference
US 4,623,476, which have good absorption properties and are intended
especially for the mopping up
of oil or food residue or for the wiping of electronic parts. Absorbent wipes
of non-woven material
for single use (disposables) are used in the hygiene, cosmetic and medical
fields and consist of either
so-called air laid non-wovens or of water jet needled non-wovens. They are
often impregnated with
liquids which include skin care substances.
Air laid non-wovens are understood to be such non-wovens the fibre components
of which are
evenly mixed with one another in an airstream and deposited on a sieve. The
components of such an
air laid non-woven are comparatively short fibres. Dust and components with
fibrous structure such
as, for example, cellulose and/or synthetic pulp (cellulose) are thereby used
at least as a portion. The
bonding of the air laid non-woven to achieve a structural integrity usable for
the intended application
is usually a known adhesive bonding method with polymer dispersions and/or the
use of melt or
adhesive fibres. It is a disadvantage of non-wovens consisting of such short
fibres that significantly
lower strengths are obtained with binder amounts comparable to those used in
carded non-wovens.
Air laid non-wovens, which are used as wipes in hygienic, cosmetic or medical
applications have -
because of their process related technical proximity to paper and especially
when high portions of
cellulose fibres are used, also in the wetted condition - significant
disadvantages during use on
sensitive human skin with respect to their softness and suplety. The second
class of absorbent non-
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wovens for absorption and mopping purposes are those which fibres that are
usually completely
binder free and solidified exclusively by high-pressure water jets, which
means hydrodynamically.
Fibre materials are thereby mixtures of hydrophilic fibres such as rayon
staple, lyocell, cotton,
cellulose and fully synthetic fibres, such as polyester or polypropylene. The
absorbent non-woven
wipes thereby have a high structural integrity (strength) but only a small
material thickness, which
means a high material density which is connected with a low absorption
capacity per surface weight.
Although it is known to provide the described air laid non-wovens and waterjet
needled non-wovens
with a certain surface structure, those non-wovens have only a relatively
shallow two dimensional
structure for use as wipes in hygienic or medical applications. Those wipes,
especially when used for
the wiping or removal of dirt particles, for example, excrements from the
human skin, have the
disadvantage that the latter are only moved along the surface of the skin and
not taken up by the wipe.
SUMMARY OF THE INVENTION
It is now an object of the invention to provide a high volume non-woven which
has very good
haptics and dexterity also with regard to softness and drapability and already
in the nonfluid-absorbed
condition.
This object is achieved in accordance with the invention with a high volume
non-woven which
at least in a preferred direction is interleaved with a textured yarn, whereby
a non-woven of endless
filaments and/or staple fibres with a surface weight of 5-100 glm2 is
interleaved with a textured.
multifilament yarn with a titre in the range of 10-400 dtex, whereby the
distance of the multifilament
yarn threads from one another is 1/cm up to 10/cm and the mesh number is
O.S/cm - 8/cm and the
multifilament yarn threads are shrunk by 3-80 % through humid or wet thermal
treatment. The length
reduction of the textured multifilament yarn in the interleaved non-woven is
carried out with
oversaturated steam or hot air treatment, whereby as much as possible low
contact or contact-free
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shrinking conditions are selected. The base non-woven can furthermore be
interleaved with yarns in
the machine direction (warp direction) as well as in the transverse direction
(woof direction).
Textured multifilament yarns can be in both directions. However, for cost
reasons, it is advantageous
to use textured multifilament yarns only in one preferred direction and to use
in the other preferred
direction non-textured multifilament yarns or the even more cost efficient
monofilaments. However,
particularly voluminous structures are achieved with absorbent non-wovens warp-
interleaved with
textured multifilament yarns.
The preferred high volume non-woven in accordance with the invention has a
corrugated raised
structure and thereby a ridge and trough type shaping of the planar structure,
which improves its
wiping effect and dirt storage capacity, especially in between the ridges. A
conformable absorbent
single use wipe is achieved which is stretchable in at least one direction and
which despite a high
absorption capacity has a high structural integrity.
A preferred high volume non-woven includes a base non-woven of endless
filaments and/or
staple fibres of a surface weight of 7-60 g/mz which is interleaved with a
textured multifilament yarn
with a titre in the range of 30-300 dtex, whereby the distance of the
multifilament yarn threads from
one another is 3/cm to 7/cm and the mesh number is 0.5-4/cm and wherein the
multifilament yarn
threads are shrunken by 5-60 % by way of a humid or wet thermal treatment. The
interleaving of
textured yarns in a preferred direction results at the same time in a surface
shrinking in direction of
this preferred direction. No shrinkage occurs at an angle of 90° to
this preferred direction. However,
if textured yarns are interleaved in both directions, the length reduction
thereof in the warp and woof
directions depends on the number of yarns per unit length or width in the
preferred direction, their
total titre, their degree of texturing and their chemical composition.
The mesh number is understood to be the number of meshes (needled stitches) in
the warp
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direction. The warp-interleaved yarns are preferably linearly oriented.
However they can also be
stitched in at a zig-zag orientation in the warp direction.
The fissled-through absorbent non-woven is subsequently subjected to a
shrinking process in
such a way that the non-woven itself does not undergo a surface reduction but
only the interleaved
textured yarns undergo a shortening of their length. This leads to a partial
reorientation of the
absorbent non-woven into the third dimension. The preferred direction of the
textured yarns, and the
fact whether or not they are interleaved in two preferred directions,
determines the geometry of the
three dimensional structure.
The textured multifilament yarns can be made of the same or two different
homofilaments or of
bi-component filaments. Polymeric materials usable for the textured threads
are all of those which are
in the prior art, for example, polyamide 6, polyamide 6.6, polyethylene
terephthalate, polybutylene
terephthalate, copolyesters of different compositions, one or more component
polyolefins and/or
metalocene catalyzed polyolefins. Biologically decomposable thermoplastics can
equally be used as
the basis for the textured threads, such as, for example, polyester amides or
copolyesters on the basis
of terephthalic acid and adipic acid with aliphatic and cycloaliphatic dioles
as described, for example,
in WO 96/255446, DE 44 40 858 and DE 195 185.
Such a non-woven has proven especially conforming, whereby a wiping cloth is
obtained
having a high absorption capacity and a high structural integrity.
In an especially preferred high volume non-woven in accordance with the
invention, a base
non-woven of endless filaments and/or staple fibres with a surface weight of
10 to 40 glcm2 with a
partial, pattern type consolidation covering 2-35 % of the surface, is
interleaved with a textured
multifilament yarn, whereby the multifilament yarn threads are shrunken by 8-
35 % . The partial
consolidation can be achieved by heat and pressure, by ultrasound melt bonding
or by adhesive
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bonding by way of roto-gravure or template printing. In an especially
advantageous embodiment of
the invention, needled non-wovens are used as the planar base, whereby
hydrodynamic needling with
high pressure water jets is preferred for the manufacture thereof over
mechanic needling with a
needling machine.
To provide an especially high structural integrity, the partial, pattern type
consolidation
preferably covers 4-25 % of the surface of the high volume non-woven.
Especially preferred is a high volume non-woven wherein the non-woven includes
fibres and/or
filaments of a titre between 0.05 and 4.4 dtex, whereby up to 20 wt. % can be
fibres andlor filaments
with a titre higher than 4.4 dtex with the proviso that the arythmetic mean of
the average fibre and/or
filament titre of all fibres and/or filaments in the non-woven is not higher
than 4.4 dtex. If the fibre
and/or filament titres are lower than 0.8 dtex, this concerns fibres or
filaments manufactured with the
so-called melt-blowing process, or so-called multicomponent split fibres which
before splitting have a
titre of above 0.8 dtex and after splitting a fraction thereof. The splitting
is preferably carried out with
high pressure water jets. However, the splitting can also be carried out by a
mechanical softening or
microcrepe process (Micrex) as described in document EP 0 624 676 or by
treatment with hot steam
or hot water according to reference US 5,759,926 for spunbonds, or according
to the methods
disclosed in reference EP 0 864 006 far microfibre melt-blown filaments.
Ethoxylated polysiloxane
can be added as a hydrophilization agent in an amount of about 1-5 wt. % to
the hydrophilic spinning
mass or the more hydrophilic of the two spinning masses, to aide the splitting
or to increase the
incompatability of the two polymers used in the split phase. All known fibre
and/or filament cross
sectional shapes can be considered for the high volume non-woven in accordance
with the invention.
For example, round, oval, rectangular and/or trilobal shapes can be used.
Furthermore, fibres and/or
filaments with groove shaped recesses along their surface are also included.
The split microfibres
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and/or filaments normally have a pie-shaped cross-section.
The high volume non-woven is preferably one wherein the multifilament yarn
shrinkage
inducing temperature is selected about 25°C below the softening
temperature of those fibres and/or
filaments in the non-woven with the lowest softening point. Normally, the
interleaved carrier itself is
not subject to surface shrinkage. In accordance with the invention, the length
reduction of the textured
multifilament yarn is larger than the surface reduction of the non-woven by
inherent shrinkage in
direction of the interleaved filament yarn. The fibre pile can also include a
portion of shrinkable
fibres, for example physically modified polyester, medium shrink fibres or
polyester high-shrink
fibres on the basis of polyethylene terephthalate. The proportion of these
shrink fibres is thereby
selected so low that during the shrinking the process the surface shrinkage of
the non-woven in the
preferred direction of the multifilament yarn interleaving is lower than the
multifilament yarn
shortening. The polyester shrink fibre portion in the non-woven is preferably
in the range of 3-40
wt. % , more preferably in the range of 5-25 wt. % . The integrity of the
multifilament yarn interleaved
non-woven can be further increased with this addition which improves the wear
resistance during
wiping.
Especially preferred is a high-volume non-woven wherein the non-woven is
racked transverse
to the machine direction. The reorientation of the base non-woven into the
third dimension can be
increased by racking the interleaved non-woven transverse to the machine
direction. Known methods
for transverse racking of planar structures can herefore be used, whereby
racking by way of guiding
the interleaved non-woven over racking rollers is preferred, since this
process is especially gentle on
the material compared to the use of racking frames, and leads to an even
distribution of the transverse
forces over the width of the material web. Furthermore, bonds or mutual
mechanical ties between the
fibres and/or filaments of the base non-woven can be again partially broken or
loosened by racking in
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transverse direction whereby an additional significant increase is achieved in
softness and conformity
of the high volume non-woven in accordance with the invention is achieved. An
additional effect of
the racking in transverse direction is the increased surface of the finished
material proportional to the
racking factor and, thus, an economically advantageous increase in the
productivity of the overall
process. The racking factor is thereby defined as the quotient of the width of
the material web after
the racking process divided by the width of the material web before the
racking process.
The high volume non-woven preferably includes about 20 wt. % inherently
hydrophilic fibres
and natural filaments with the remaining portion to 100 wt. % being synthetic
fibres and/or filaments.
The starting fibres andlor filaments for the base non-woven can consist of one
or mare components.
A portion of about 20 wt. % of the fibres and/or filaments used are thereby
permanently hydrophilic.
The hydrophilicity of the fibres and/or filaments can be inherent in the
respective polymer as is the
case, for example, with cellulose based or polyamide based fibres. However, it
can also be achieved
by adding a hydrophilizing agent to the melt of the fibre-forming polymer
before its spinning. The
term "permanently hydrophilic" in accordance with the present invention refers
to a fabric of fibres
and/or filaments wherein the hydrophilizing components migrate during storage
from the interior of a
fibre to the fibre surface. Rayon staple is preferably used as fibre with
"inherent hydrophilicity", for
example cellulose fibres solution-spun in N-methylmorpholene-N-oxide (lyocell,
cotton or cellulose).
The lyocell fibres can be smooth or crimped. Although in accordance with the
invention portions of
less than 20 wt. % of inherently hydrophilic fibres can be used in the non-
woven, the danger exists
that during storage of a folded wet wipe piled in a stack the aqueous emulsion
added for skin care
accumulates in the lower layers. This would lead to a tendency of drying out
of the upper wet wipes
layers and would thereby negatively influence their wiping properties and the
release of the skin care
substances during the wiping process.
CA 02352864 2001-07-11
Especially preferred is a high-volume non-woven wherein at least a portion of
the synthetic
fibres and/or filaments have a hydrophilic finish. The non-inherently
hydrophilic fibres and/or
filaments which form the remaining portion up to 100 wt. % are preferably
fully synthetic. In the case
of endless filaments, they are subsequently provided with a hydrophilic finish
in the non-woven using
known surface active substances. The adhesion of the externally applied
hydrophilizing agents and the
duration of the hydrophilic effect are thereby significantly determined by the
chemistry of the surface
active agent used and the surface properties of the fibre and/or filament
material.
The high volume non-woven preferably includes at least a portion of
superabsorbent fibres
and/or filaments, or fibres and/or filaments having a core covered with a
superabsorbent polymer.
The use of superabsorbent fibres andlor filaments or coated fibres and/or
filaments coated with
superabsorbent polymer improves the absorption capacity of the non-woven in
accordance with the
invention.
Furthermore, the high volume non-woven preferably includes crimped and/or
colored fibres
and/or filaments. The fibres and/or filaments of the non-woven can be smooth
or two or three
dimensionally crimped, or crimped fibres or filaments admixed with uncrimped
fibres or filaments.
However, crimped fibres or filaments are preferably used, since they improve
the absorption
capacity. Depending on the intended application, the fibres and/or filaments
can be colorless or
colored in the spinning mass with a colorant and/or white pigment. A portion
of the fibres can
thereby be textile colored before or after the formation of the non-woven or
after the finishing of the
multifilament yarn interleaved and shrunken high-volume non-woven.
The high-volume non-woven is preferably impregnated with a lubricant such as
silicone oil.
Furthermore, the non-woven preferably additionally includes a portion of
siliconized fibres or
filaments with other lubricants. However, the lubricant can also be
subsequently applied to the non-
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woven either after the pile depositing thereof or during the solidification to
a textile planar structure.
Application of a lubricant such as, for example, silicone oil onto the fibres
and multifilaments of the
non-woven before the interleaving with a multifilament yarn can reduce the
friction of the stitching
needles with the non-woven during interleaving of the multifilament yarn
especially in non-wovens of
higher surface weight.
The high-volume non-woven preferably has two sides of different composition
and/or structure.
The non-woven therefore preferably consist of several different fibre and/or
filament layers which are
connected to a laminate by way of known binding techniques and already prior
to the interleaving
with the multifilament yarn. By using different fibre or filament layers on
the two main sides of the
high volume non-woven, different liquid absorptions and wiping properties can
be achieved and
accordingly used. For example, by using a high-volume non-woven with different
sides, one can
differentiate between a pre-cleaning and a follow-up cleaning. Furthermore it
can be better optically
and haptically differentiated for the user of the high-volume non-woven which
side of the non-woven
in accordance with the invention is intended for the take-up of dirt particles
for an optimum wiping
success.
The high volume non-woven is preferred folded one or more times. The folded
shape is used
for wiping, cleaning and personal hygiene purposes. Volume-stable disposable
wipes with very high
absorption capacity are obtained especially in folded form.
The high volume non-woven is preferrably impregnated with cleaning or care
emulsions. For
example, aqueous emulsions are preferaby applied to the high-volume non-woven.
Furthermore, after
the shrinking, bonding agents can be applied to one or both sides by known
methods. Aqueous plastic
dispersions are preferably used herefore, which are mixed for improvement of
the hydrophilic
properties with wetting agents and/or hydrophilizing polymers. The binder
agent can additionally
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function as carrier for color pigmentation, for example, a white pigmentation
of the product.
Furthermore, the binder agent can also be mixed with abrasive and organic
particles such as
corrundum in order to achieve at least on one side an abrasive action during
the wiping or cleaning
process. In that case, polymer dispersions are used which produce a very hard
film. The polymeric
binder can also be applied by way of a full-bath dipping process.
The high volume non-woven in accordance with the invention is preferably used
as wiping,
cleaning or personal hygiene cloth.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detail in the following by way of
example only and
with reference to the drawings wherein
Figure 1 is a schematic illustration of a high-volume non-woven in accordance
with the
invention;
Figure 2 is a cross-section through a non-woven in accordance with the
invention taken along
line A-A in Figure 1 and enlarged; and
Figure 3 is a cross-section through a high-volume non-woven with an
asymetrical corrugation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 schematically illustrates a preferred high-volume non-woven 1 in
accordance with the
invention whereby the non-woven base material 2 is raised in corrugations 3
which include peaks 4
and valleys 5. The direction A-A represents the machine or warp direction. The
textured and
shrunken multifilament yarns 6 which are oriented in warp direction are
interleaved into the non-
woven 2 at positions 7 and form the loops 8. The regions 9 of the
multifilament yarn 6 which are
oriented in direction A-A are elastic between the loops 8 or the positions 7.
The yarn regions 9 illustrated in Figure 2 consist of multifilament threads 6
highly textured by
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shrinking and having a structure like elastic springs, which provides the
product with exceptional
softness and elasticity. The base non-woven 2 with its corrugations 3,
consisting of peaks 4 and
valleys 5, is preferably made of crimped fibres 10 which are intensively
entangled with one another
by waterjets. Figure 2 illustrates the case of a symmetrical corrugation 3,
whereby the yarn regions
12 and 13 to the right and left of the maximum height 11 of the corrugations
respectively occupy half
of the length of the yarn region 9. The maximum corrugation height 11 is
thereby defined as the
distance of the yarn region 9 from the peaks 4 of the corrugations 3.
Figure 3 shows an asymmetric corrugation 3 of the non-woven 2 wherein the
maximum height
11 of the corrugations 3 is shifted in direction of one of the yarn regions 12
or 13. Such a case can
occur when the high volume non-woven is compressed after the shrinking process
or subjected to
friction.
The textured threads wound on warp booms are interleaved into the non-woven
using known
methods, preferably only in warp direction, whereby the already above
described limits and teachings
must be obeyed with respect to the non-woven parameters (weight, structure,
presolidification
method, etc.) and interleaving parameters (type of the textured yarns, overall
titre in dtex, number of
loops/cm).
After the interleaving of the textured multifilament yarns, the planar
structure is subjected to a
humid shrinking treatment in oversaturated steam, in boiling or nearly boiling
water, or expose to hot
water treatment in a pressure vessel (for example similar to a textile
polyester dispersion coloring).
Temperatures above 100°C are suitable but less preferred for cost
reasons.
The choice of the temperature for the yarn shrinking in the planar structure
is determined by
the composition of the material of the base non-woven and the textured
multifilament yarn. The
temperature and the exposure times are preferably selected such that the non-
woven material itself is
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not subject to a surface shrinkage and only the textured yarn undergoes a
length reduction by
shrinkage. Thus, the textured multifilament yarns used should preferably
consist of such filaments
which have a relatively high melting or softening point, for example
polyethylene terephthalate,
polybutylene terephthalate, polyamide 6 or polyamide 6.6 or bicomponent yarns
of two of these fibre
filaments and the fibres of the non-woven material should consist of a
thermolstable fibre material.
The wave type structure important for the invention prevents the use of the
same polymer in the non-
woven material as in the textured yarn. Fibres are preferably used in the non-
woven which are either
not thermoplastic and do not decompose at the shrinkage temperature of the
yarn or higher melting
fibers for example, polyethylene therephthalate, polybutylene terephthalate,
polyamide 6 or
polyamide 6.6 or bicomponent fibres of those polymers or mixtures of the
mentioned fibres.
The planar product is subsequently either dry folded and/or provided with an
aqueous core
lotion impregnation, subsequently folded into shape and placed as a stack into
hard, form stable, and
reclosable plastic containers (dispensered box) or welded in the form of a
stack of several folded
cloths into flexible foil bags (refill packages).
Example 1
A carded staple fibre pile consisting of 60 % rayon staple dtex 1.5140 mm and
40 % polyestered
dtex 1.5/38mm on the basis of polyethylene terephthalate is laid down on a
transport conveyor and
transported to the dewatering sieve of a high-pressure water jet needling
arrangement. The metal
sieve is fine meshed and has a mesh number of 100. After a prewetting with the
water, the fibre pile
is initially treated from one side with directed high-pressure water jets then
inverted and solidified
from the other side with high pressure water jets. Superfluous water is
subsequently suctioned off
through the passage over a vacuum slit up to a residual wetness of 98 % . A
drying with a so-called
belt dryer is subsequently carried out. At the wind-up station a surface
weight of the water jet needled
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non-woven of 49 glm2 results.
The water jet needled non-woven is interleaved on a fissle machine in warp
direction with
textured polyester multifilament yarns. Those yarns consist of 36 individual
filaments with an
individual titre of 1.39 dtex, whereby an overall titre of 50 dtex results for
the yarn.
The yarns interleaved in warp direction have a loop number in warp direction
(equals machine
direction) of two per cm. The number of parallel interleaved yarns is l8/inch
(7.11 per cm). The
surface weight after the warp interleaving is 61.8 g/m2.
In a third process step, the warp interleaved non-woven is subjected to a
thermal shrinking
treatment at 140°C over a time period of 20 seconds. Under those
conditions a shortening of the
textured yarns in the warp interleaved non-woven of 16 % is achieved and
corrugated structure of the
latter. A surface weight of 73.6 g/m2 results.
Example 2
The composition of the water jet needled non-woven and the conditions of the
interleaving of
the textured polyester yarns as well as their loop and yarn number per length
unit are identical.
However, in place of a dry thermal treatment a humid thermal treatment with
superheated steam was
carried out at 125°C and with a residence time of 20 seconds.
A significantly higher shrinkage compared to Example 1 resulted in machine
direction. It was
24.5 % with a more clearly pronounced wave structure as in Example 1. The
width of the product
remained unchanged so that an overall shrinkage of 24.5 % and a surface weight
of 81.8 g/mz
resulted.
Example 3
The fibre mixture of the water jet needled non-woven produced in Example 1 was
replaced
with one made of 100% rayon staple dtex 1.5/38mm and the dry weight after the
water jet
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consolidation reduced from 49 to 20g/m2. The yarn interleaving as described in
Example 1 was steam
shrunk according to Example 2. The surface weight after the warp interleaving
was 32.2 g/m2.
A shrinkage or length reduction of the planar product in machine direction of
50. 3 % resulted.
The resulting finished material weight was 54.8 g/m2.
Example 4
Endless filaments are extruded from a melt which are shock cooled by cooling
air streams and
then stretched by way of directed air streams to a titre of 1.7 dtex and then
deposited on a deposition
conveyor into an unsolidified endless filament non-woven.
The endless filaments have a pie structure in cross section with overall 16
pie shaped pieces,
whereby respectively larger and smaller pie pieces alternate. The larger pie
pieces consist of
polyamide 6.6 and the smaller ones of polyethylene terephthalate, so that the
overall 16 pie pieces
divide into 8 large ones made of polyamide 6.6 and 8 smaller ones consisting
of polyethylene
terephthalate. The weight portions of the so called PEI fibre divide into 65 %
polyamide 6.6 and 35
polyethylene terephthalate.
An anti-static agent or hydrophilizing agent was added to the spinning mass of
the polyamide
6.6 portion.
The unsolidified endless filament non-woven was transported to a water jet
needling unit as
described in Example 1.
The high-pressure water jet treatment here did not only lead to an intensive
entangling of the
fibres with one another but also to a splitting of the fibres up to a degree
of splitting of 93 % . The
degree of splitting was roughly determined by counting the created microfibres
under a scanning
electron microscope. The titre of the microfibres on the basis of polyamide
6.6 in polyethylene
terephthalate calculates as 0.138 dtex for polyamide 6.6 and 0.074 dtex for
polyethylene terephthalate
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of the pie configuration (16 piece pie) and the overall titre of the
endsplitted endless filament. The
specific density of polyamide 6.6 is 1.14 and the one of polyethylene
terephthalate 1.37 g/cm3, which
calculates in a fibre fineness for the polyamide 6.6 microfibres of 3.92 ,um
and for the polyethylene
terephthalate microfibre of 2.62 ,um.
After drying of the water jet needled non-woven splitted into microfibres with
a weight of 34
g/m2, the textured multifilament polyester yarns were interleaved as described
in Examples 1-3 in
machine direction. Subsequently, the product was subjected to a contact free
air supported hot air
treatment at 210°C over a period of 10 seconds.
A longitudinal shrinkage/longitudinal shortening of 32.2 % was achieved with
corrugation. The
surface weight of the finished material was 69.3 glm2.
Comparative Example A
As comparative Example A, Example 1 after the water jet needling is used.
Comparative Example B
Comparative Example B corresponds to Example 1 after the water jet needling
with the
difference that instead of the fine 100 mesh sieve in the water jet needling
arrangement a coarser
sieve with 20 mesh is used. A non-woven with perforated structure is produced
thereby.
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Test SurfaceThickness Water HZK NIScm Shrinkage
ParameterWeight mm Uptake Longitudinally
g/mz g/mz
1-ply4-ply 1-ply 4-plylongitudinallytransverse
Example73.6 1.84 7.12 963 3374 65.3 12.1 16.0
1
Example81.8 1.93 6.93 952 3467 23.8 10.1 24.5
2
Example64.8 2.07 7.98 935 3838 84.9 3.8 50.3
3
Example69.3 1.87 7.05 289 1176 56.2 25.3 32.2
4
Example49 0.91 4.05 577 2366 79.1 16.3 0
Example54 1.04 4.36 542 2205 93.2 18.8 0
B
(HZK = maximum tensile strength)
-16-
