Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
YISCOSUISSE 13137~3 CA 8793
The invention relates to a process for pre-
entangling an undra~n or partially drawn (LOY, MOY, POY,
FOY) synthetic multifilament feed yarn for the draw;ng,
the texturing and/or the draw-texturing process for the
production of a textured or smooth yarn for textile sheet-
like structures and to the yarn produced by the process.
Trouble-free unwinding in the further processing
of mu~tifilament synthetic yarn requires adequate yarn
cohesion. Proven ways of producing multifilament yarns
of adequate cohesion are twisting and sizing. However,
both the methods are very demanding ;n terms of machine
and transport resource requirements.
The intention of producing a usable yarn cohe-
sion was also behind the development of aerodynamic pro-
cesses in which the yarn, which is under a defined ten-
sion, is entangled by means of compressed air from a jet.
This operation takes place after the texturing or draw-
ing process.
EP-A-0,137,088 discloses an entanglement process
whereby an undrawn or partially drawn feed yarn, for a
false twist texturing process, ;s slightly entangled
under an air pressure of about 0.5 bar in order not to
disturb the actual texturing process with overly inten-
sive sites of entanglement in the form of knobs. The
knobs produced in the feed yarn must disappear again in
the further processing of the yarns in order to avoid
flaws. The object of the known process is to reduce the
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number of broken ends, in particular in the case of the
finely fibrillate yarns. After texturing, these yarns
then have to be entangled again, the resulting cohesion
of the textured yarn having the same function as ~ith
S the feed yarn, namely to improve and/or guarantee fur-
ther processabil;ty. Ho~ever, the entangle~ent sites
produced in the kno~n process have the disadvantage that
they intertere ~ith the uniformity of the appearance of
the final fabric, in particular in the case of fine
1Q deniers. It has hitherto not been possible to produce
~oven fabrics from textured yarns which are sufficiently
entangled to give satisfactory un~inding ~ithout these
~oven fabrics having an unlevel appearance.
It is an object of the present invention to pro-
vide a process ~hich ensures good yarn cohesion in a
textured or dra~n filament yarn and ~hich, in the fur-
ther processing of said yarn, guarantees trouble-free
un~inding and makes it possible to produce a textile
sheetlike structure ~hich ideally is free of markings.
This object is achieved according to the inven-
tion ~hen the entangR ng takes place under an air pressure
of ~.S to 3.0 bar preliminary to entry of the feed yarn
into the drawing, texturing and/or dra~-texturing zone.
It has been possible, surprisingly, to increase
the intensity of feed yarn entanglement in such a ~ay
that, on the one hand, the texturing process is not
interferred ~ith and, on the other, the textured yarn
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is given the requisite cohes;on for further processing
without a further entangling process. This is also true
for kno~n dra~ing processes ~here the feed yarns are drawn
into smooth yarns. In the pre-entanglement according to
the ;nvention, the entangling takes place preliminary to
entry of the yarn into the texturing means and under an
air pressure ~ithin the jet of about 0.5 to 3.0 bar, in
particular of 1.0 to 2.5 bar, preferably of 1.5 to 2.0
bar.
It is advantageous and surprising that the pre- -
entangled yarn, which may be not only a textured yarn
but also a smooth yarn, shows a "continuous" entangle-
ment characteristic. The term "continuous" entanglement
as used herein covers a form of entanglement wh;ch has
no pronounced entanglement sites, unlike existing en-
tanglement processes for which distinctly visible knobs
at period;c intervals are typica(.
~ ithin the preferred pressure range the number
of snar~s likewise is at a minimum of about 80 snarls
per 100,000 m of yarn length and produces a woven fabric
without markings. Snarls are to be understood as mean-
ing broken filaments and/or yarn elements protruding
from the core of the yarn. The snarls were measured
with a measuring head from TORAY, which orks in accor-
dance ~ith the electro-optical principle. The test
speed ~as 1,û00 m/min, and the length of yarn tested
per variant was 1.6 x 105 m.
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The invention ~ill be further illustrated by
reference to examples.
Example 1
The feed yarn-used ~as a POY polyester yarn
having a nominal count of dtex 100 f 7Z. The most sui-
table entanglement jets are enclosed t~o-hole jets,
having for example an air passage diameter of 0.7 mm.
Ho~ever, it is also possible to use other commercia~y
available entanglement jets ~hich guar\antee a constant
pressure ~ithin the claimed range. The entanglement vas
follo~ed by texturing at 500 mlmin on an FK6-CF textur-
;ng machine from GARMAG AG.
For each variant, 8 packages of 1.8 kg each vere
produced. The test results are sho~n in the table belo~.
~n the tables: cm = tenacity x~elongationi
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Table 1
Entanglement Unentangled Pre-entangled Conventional~r
I I entangled
Air pressure bar _ 0.5 1 0 1.5 2.0 2.5 2.5
inear densi~y-
dtex 105.6 103.5 ~ l04.0 104.0 103.6103.2
Elongat;on X 24.5 24.2 23.8 26.7 26.7 27.0 27.6
Tenacity cN/
¦ tex 31.6 32.2 ~ 33.0 33.3 33.6 34.4
cm 156.4 158.4 157.1 170.5 172.1 174.6 180.7
Entanglement Knlm 21.0 30.0 39 0 51.0 51.0 65.0 87.0
Snarls/100,000 m 1 422.0 235.0 110.0 84.0 80.0 128.0 340.0
Broken endsl
¦ 100,000 m 4.6 0.5 0.34 0 0 0 0
The degree of entanglement ;ncreases continuously
from a base value of 21 knobs/m, ;n the case of a yarn
textured ~;thout entangling means, to 65 knobs/m at an a;r
pressure of 2.5 bar. It ;s essent;al for further
process;ng and ;t is surprising that the number of knobs
is far lo~er than in a yarn conventionally entangled at
Z.5 bar ~;thout deter;oration in unw;nd;ng. In the case
of the variant referred to as conventional~y entangled,
the entangling ;s effected in a conventional manner
following texturing and before winding up.
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Example 2
The feed yarn used ~as a POY polyester yarn hav-
ing a nominal count of dtex 167 f 36 octolobal which was
processed by the process according to the invention. The
test results are sho~n in Table 2. The same trends were
found in unwinding properties, the number of knobs and
fabric appearance.
Table 2
\
. .
Entanglement Pre-entangled Conven-¦
l i tional
Air pressure bar 0 1.0 1.5 2.0 2.5 2.1
Linear density dtex 176.0 176.0 176.0 176.0 177.0180.0
Elongation X 27.5 27.5 27.5 27.5 27.527.5
Tenacity cN/
tex 34 5 34.5 34.5 34.5 34.433.7
_ ,.
cm _ _ 180.9 _ _176.7
Texturmat
crimping X 39.6 39.8 39.0 39.6 39.433.4
Crimp
¦ stabili_y X 184.9 84.4 84.1 84.8 84.277.6
Entanglement Knlm 15.6 29.0 29.4 _ 31.232.877.7
Broken ends/
1 100,000 m 1 1.3 0.2 _ 0 _ 0 .
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A summary of the examples is further illustrated
in the drawings, ~here
figure 1 sho~s a comparison bet~een the results measured
for the entanglement according to the invention
S and the prior art,
Figure 2 shows a fabric comprising an unentang~ed yarn,
Figure 3 shows a fabric produced by pre-entang~ement ac-
cording to the invention under an air pressure
of 2.5 bar,
1û Figure 4 sho~s a fabric produced by conventional entang~e-
ment under an air pressure of 2.5 bar, and
Figure 5 sho~s a variant of the measured results obtained
from a different linear density than in Figure 1.
Figure 1 shows the essential difference bet~een
a non-entangled yarn 1, a yarn 2 entangled under 2.5 bar
according to the invention and a yarn 3 conventional~y
entang~ed under 2.5 bar in terms of the measurements
recorded on a yarn thickness measuring instrument. The
measurements ~ere carried out on an entangeLement measur-
ing instrument of type KMG-4 from VISCOSUISSE SA.
The fabric obtained according to Figure 2 from an un-
entangled yarn is free of marking. Ho~ever, very poor
un~inding during ~eft insertion (in ~eaving) on account of
the frequent yarn breakages makes processing of such a
- 25 yarn an uneconomical proposition.
Figure 3 sho~s the fabric resulting from pre-en-
tanglement according to the invention under 2.5 bar. It
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is true that some entangelement knobs are st1ll visible,
but the appearance of the fabric has to be classified as
good.
Figure 4 depicts a variant produced by conven-
S tional entanglement under 2.5 bar. This fabric is un-
usable on account of the very strong marking ~ith en-
tanglement knobs.
In a variant according to figure S, the yarn
thickness measurement trace shows the typical difference
betueen the tvo entanglement processes for a yarn having
a nominal count of dtex 167 f 36. Curve 4 represents the
pre-entanglement according to the invention, ~hile curve
5 applies to a conventionally entangled yarn.
All the samples sho~n ;n Figures 2 to 4 ~ere
~oven on a gripper projectile ~eaving machine ~ith
~eft insertion at 800 m/min and then dyed and set.
The textured yarn produced by the process accord-
ing to the invention results in a satisfactory appearance
of the ~oven fabric since it is evidently the case that,
in the course of the texturing process, the entanglement
sites introduced disappear only to such an extent that the
residual entanglement remaining behind comes close to so-
called "continuous" entanglement. An advantage of quasi-
continuous entanglement is in particular the ~o~ degree
of marking in the fabric coupled ~ith a degree of yarn
cohesion ~hich is sufficient for satisfactory processing.
