Note: Descriptions are shown in the official language in which they were submitted.
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POLYMER FILAMENTS HAVING PROFILED CROSS-SECTION
Field of the Invention
This invention relates to synthetic polymer
filaments with an "open hollow" profiled cross section
normal to the longitudinal axis of the filament. The
invention further relates to spinneret plates for melt
extrusion of the filaments, and to methods~of
manufacture of the-'filaments by melt extrusion.
Background
Textile fibres or filaments from synthetic
polymers, particularly polyamide polymers like nylon 66
and nylon 6, and multifilament yarns melt extruded from
the same polyamide polymers, are produced for apparel
uses typically as partially oriented yarn (POY) and
drawn yarn. POY will have an elongation to break
greater than about 55o and drawn yarn will have a lower
elongation. Circular is the most common cross
sectional shape for each filament comprising the
multifilament yarns of either type, e.g. POY and drawn
yarn. Variation on the individual filament cross
sectional shapes include trilobed or 6-lobed, disclosed
in Japanese Kokoku patent document 01-20243 (Nihon
Ester KK), the scalloped oval cross section as
disclosed by in US Patent 5,834,119 (Roop) and hollow
polyamide filaments with a single longitudinal void,
disclosed in US Patent 5,604,036 (Bennett et al.).
All of the foregoing examples are known variants
of profiled cross sectional shaped POY and drawn yarn.
Filaments with cross sectional shapes other than
circular provide multifilament yarns for fabrics and
garments with varied visual aesthetics, opacity and
cover and lighter weight. Yarns from hollow filaments,
for example the yarns of the last mentioned United
States patent; provide lighter weight fabrics and
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garments and enhanced heat retentive properties versus
conventional circular filaments, without a longitudinal
void. Hollow filament yarns are particularly suited
for apparel applications when textured by the
conventional processes, e.g. air jet texturing (AJT)
and false twist texturizing (FTT) to obtain bulky
yarns. Hollow flat yarns for direct use in weaving
applications are also known.
Both partially oriented and flat nylon yarns in a
high void volume hollow are disclosed by Bennett et al.
However, filaments with longitudinal voids are
difficult to close perfectly at spinning, and may also
deform substantially during the texturing process.
This may result in a letter 'C-shaped' filaments and/or
collapsed tube cross sectional shapes. Letter C-shaped
filaments are able to pack closely together with a loss
of open space among neighbouring filaments. In
addition, letter C-shaped cross sectional filaments and
collapsed tube cross sections lead to undesirable yarn
and fabric properties as a result of such occurrences.
Increased fabric density and diminished heat retention
of the fabric and garments are among the undesirable
properties. Furthermore, yarns from filaments with
varied amounts of ruptured longitudinal voids
contribute to dyed fabric streakiness and the intact
filament voids provide opportunistic bacteria with a
place to flourish.
It has now been found that the above-enumerated
disadvantages can be overcome by the production of
polymer filaments having a novel cross-section.
The present invention provides a profiled filament
from synthetic polymer having an "open hollow" cross-
sectional shape normal to the longitudinal axis of the
filament. The cross-section is dimensioned to prevent
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a first filament from interlocking with a second
filament having the same cross-section. This means a
region proximate to each tip of the cross-section is
wider than a spacing between said regions defining an
opening to the open hollow cross-section.
The profiled cross sectional shape filaments of
the invention are provided by the novel shape and
design of the extrusion capillary. The filaments of
this invention are prepared directly by melt extrusion
of synthetic polymer through a multi-capillary
spinneret plate. The term "open hollow" denotes a
generally C-shaped or U-shaped cross-section having a
hollow center, and a solid region defining wall portion
extending around the hollow center to enclose the
hollow center, but with an opening in one side of the
wall linking the center to the outside of the filament.
The opening is narrower than the diameter of the hollow
center, thereby forming a throat or constriction
between the hollow center and the outside of the
filament.
Preferably, the filament comprises a solid part
substantially enclosing a central hollow region. An
opening leads from the exterior of the filament into
the central hollow region. The solid part includes
legs that terminate in feet. Confronting surfaces of
the feet define the throat (the narrowest dimension) of
the opening. The throat of the opening subtends a
radial angle alpha (0() of not more than 90°, more
preferably not more than 75° and most preferably from
10° to 60°. As seen in Figure 1, the radial angle
alpha (0() is that angle defined between two rays R1 and
R2 originating at a point C. The point C is that point
lying on the interior surface of the solid part of the
filament that lies farthest from a reference line R3
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tangentially connecting the tips of the feet. Each ray
R1, R2 extends from the point C and lies tangent to a
point on the confronting surfaces of the feet defining
the throat of the opening D. The solid part subtends a
radial angle equal to 360° minus angle alpha (360° -
O(). Preferably, the solid part of the cross-section
subtends a radial angle of at least 270°. More
preferably the solid part subtends a radial angle of at
least 300°.
The filaments according to the present invention
are adapted to prevent inter-engagement or stacking of
the filaments. For example, hook-like engagement of
two cross sections arising from insertion of an end of
the solid part of a first filament cross-section
through the opening in the cross-section of a second
filament is prevented. This provision can be achieved
as already described, by making the solid portion of
the cross-section subtend a large radial angle, whereby
the opening in the filament cross-section is very
small. Alternatively or additionally, the ends of the
solid part of the cross section may be enlarged to
inhibit insertion into the opening of other filaments.
The solid portion of the cross-section in the
filaments according to the present invention may form a
single continuous curve. Preferably, the cross-section
comprises a "central arcuate" or base portion having
first and second ends and two side or "leg" portions.
The leg portions extending in substantially side-by-
side relationship from the first and second ends of the
central arcuate portion.
In preferred embodiments, such as the filament
cross section geometry shown in Figure 1, the filament
cross sectional shape is characterized by a central
arcuate portion 1 (extending horizontally in Figure 1)
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and first and second, generally parallel, elongated leg.
portions 2,3 (extending vertically in Figure 1) joined
to the central arcuate portion. The distal portion of
each leg (2,3) opposite the juncture with the central
arcuate portion 1 defines an enlarged foot portion 4.
Each foot portion 4 is characterized by dimension F,
the length of the foot, as shown in Figure 1. The
profiled filament cross-section is open in the center.
This open portion is bounded on three sides by the leg
portions 2,3 and central arcuate base portion 1. The
feet portions 4 are oriented in a substantially side-
by-side relationship defining an aperture between
confronting surfaces of the foot portions with
dimension D leading to the open portion, as shown in
Figure 1. The dimension D is less than dimension F.
As a result, any foot on any leg of the profiled
filament is sufficiently large with respect to the
aperture between the pair of legs on any other
identical filament to prevent a foot of the first
filament from being accommodated (interlocked) between
the legs of the other filament in a multifilament yarn
bundle, as illustrated by Figure 2.
Preferably, the polymer used to form the profiled
polymer filament according to the present invention is
a polyamide. More preferably, the polyamide polymer
has a relative viscosity, by a formic acid method,
greater than 40, and still more preferably the relative
viscosity of the polyamide by a formic acid method is
in the range of 46 to 56. Preferably, the polyamide is
selected from the group consisting of nylon 66 and
nylon 6 and copolyamides.
Preferably, the single filament linear density is
from 0.5 to 20 dtex, and more preferably it is from 2
to 10 dtex. Most preferably it is less than 4 dtex.
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Preferably, the filament cross-sectional shape is
substantially constant along the length of the
filament. Preferably, the filament non-uniformity is
less than 1 Ustero.
The profiled filaments according to the present
invention provide a lighter unit weight yarn,
particularly after texturing by AJT (air jet
texturizing) or FTT (false twist texturizing). The
yarn incorporates high free volume of air space. The
volume of air space contributes to enhanced thermal
retention of fabrics and garments produced from the
yarn. The yarn when knitted or woven into fabrics
provides a less dense fabric than similarly constructed
fabrics from solely circular cross section filaments.
Furthermore, the yarn exhibits a high moisture wicking
capacity.
Accordingly, the present invention further
provides a multifilament yarn comprising at least a
portion of the profiled filaments according to the
present invention.
Preferably, the yarn comprises at least 10o by
weight of the profiled filaments according to the
present invention, more preferably at least 250 of such
filaments, still more preferably at least 500 of such
filaments and most preferably it consists essentially
of such filaments.
The present invention further provides an article
comprising at least a portion of the yarn according to
the present invention. Preferably, the article
comprises a textile fabric that is knitted or woven
from a yarn according to the present invention.
A further aspect of the present invention is a
spinneret for the production of the profiled open
hollow filaments according to the present invention by
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melt extrusion of polymer into filaments. The
spinneret comprises a plate having upper and lower
surfaces connected by an assembly of capillaries. The
shape, size and configuration of the capillaries are
adapted to the melt spinning of filaments according to
the present invention. Specifically, either each
capillary comprises two adjacent segments as in Figure
3a, whereby the open hollow filament cross section
longitudinal to the axis of the filament is obtained as
the molten polymer streams from each segment coalesce
at a point between the segments or each capillary has
an open hollow transverse cross-section as in Figure
3b.
The preferred spinneret plate for the production
of the profiled open hollow filaments is one with each
capillary comprised of two segments in Figure 3a. Each
segment is comprised of a straight length portion 30
having at each end a junction with a pair of projecting
portions. At the first end, the pair of projecting
portions are of equal area and each comprise a straight
portion 31,32 terminating in a round portion 33,34. At
the second (opposite the first) end, are a pair of
unequal area projecting portions. The first unequal
area projecting portion is comprised of straight
portion 35 and round portion 36 and the second unequal
area projecting portion is comprised of straight
portion 37 and round portion 38. Therefore, each
segment of the capillary has three equivalent
projecting portions, two on one end and one on the
opposite end. The unique (longer) projecting portion
present on each segment is comprised of straight
portion 37 and round portion 38. Preferably, each
capillary segment is the mirror image of the other
segment. More preferably, each segment is the
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nonsuperimposable mirror image of the other segment,
for example as illustrated by Figure 3a. The
nonsuperimposable mirror image relationship means that
each segment possesses handiness in the same way as do
human left and right hands.
The open hollow filament cross section normal to
the longitudinal axis of the filament is obtained as
the molten thermoplastic polymer streams from each
capillary segment coalesce at a point between
projecting portions of the two segments. That is, the
open hollow filament cross section of the invention is
formed as the molten polymer stream coalesces between
confronting round portions 38 of the left and right
capillary segments shown in Figure 3a.
In the case where the capillaries themselves have
an open hollow cross-section, the capillary illustrated
by Figure 3b is a preferred spinneret geometry cross
section for the production of profiled open hollow
filaments. Each capillary has a cross sectional shape
comprising a first straight portion 40 with a first end
and a second end, opposite each other. Bifurcating
from the first end of the first straight portion 40 are
a second straight portion 48 and a third straight
portion 50. The second straight portion 48 terminates
in a round portion 49 and the third straight portion 50
extends to a point of bifurcation; wherein a fourth
straight portion 53 and a fifth straight portion 52
extend from this point of bifurcation. The fourth and
fifth straight portions having unequal areas and each
terminate in round portions 54 and 51. Similarly,
bifurcating from the second end of the first straight
portion are a sixth straight portion 41 and a seventh
straight portion 43. The sixth straight portion 91
terminates in a round portion 42 and the seventh
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straight portion 43 extends to a point of bifurcation;
wherein an eighth straight portion 46 and a ninth
straight portion 44 extend from said point of
bifurcation, the eighth and ninth straight portions
having unequal areas and each terminate in round
portions 45 and 47.
In a further aspect, the invention provides a
process for making drawn yarns and partially oriented
yarns (POY) with a modified filament cross section
according to the present invention. Generally, the
process comprises extruding a polyamide melt, typically
nylon 66 or nylon 6, of 40 to 60 RV (measured in formic
acid), and preferably 48 to 52 RV to form a plurality
of filaments. The spinneret according to the invention
is maintained at a temperature selected from the range
245 to 295°C, more preferably it is 280°C. Multiple
filaments extruded through the spinneret are cooled in
a cross flow of air to form solid filaments. These
filaments may be treated with oil, converged,
interlaced and drawn, or remain undrawn, prior to
winding up a multifilament yarn at a speed greater than
3000 meters per minute (m/min).
Referring now to the process schematic in Figure
5, a drawn yarn is prepared by following path A. The
melted polymer 10, a polyamide, is pumped to the spin
pack 20 and forced through spinneret plate.30 to form
filaments 40. The emerging filaments are cooled by a
cross flow of air 50, having an air velocity of about
0.15 to 0.5 meters per minute. The cooled filaments
are converged into a yarn 60, and an oil and water
finish is preferably applied to the resulting yarn
bundle at 70. The yarn 60 is forwarded through a first
air interlace jet 80 to become intermingled yarn 90.
Yarn 90 is forwarded to a first godet 92 (the feed
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roll) and its associated separator roll, wrapping
several times to prevent slippage, and then to a second
godet 94 (the draw roll) and its associated separator
roll. The draw roll 94 is moving at a surface speed of
60 to 1000, preferably 80%, greater than that of the
feed roll 92. The yarn bundle is thereby drawn
(elongated), preferably by a total factor of about 1.8,
reducing the overall yarn titer to form yarn 100. The
drawn yarn 100 is preferably treated by a relaxation
device 110 to set the draw and to relax the yarn as is
conventionally practised in the art. Any known
relaxation device may be employed, including steam,
heated fluid, hot tube, hot shoe, heated rolls. The
relaxed yarn bundle 120 is optionally passed through a
second interlace jet 130 and optionally oiled before
the relaxed yarn 140 is wound up on a tube 150 at a
winding speed greater than 3000 meters per minute, more
preferably about 3800 meters per minute. The resulting
drawn yarn has an elongation of 25 to 450, preferably
40 to 450, and a tenacity of 35 to 45 cN/tex.
Alternatively, referring now to the process
schematic in Figure 5, a partially oriented yarn (POY)
is prepared by following path B. The melted polymer
10, a polyamide, is pumped to the spin pack 20 and
forced through spinneret plate 30 to form filaments 40.
The emerging filaments are cooled by a cross flow of
air 50, having an air velocity of about 0.15 to 0.5
meters per minute. The cooled filaments are converged
into a yarn 60, and an oil and water finish is
preferably applied to the resulting yarn bundle at 70.
The yarn 60 is forwarded through a steam atmosphere
containing interfloor tube 75, as is known in the art.
The steam treated yarn 85 is intermingled at 80
partially wrapped around godet 82 and godet 84, which
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control any variations in winding tension the yarn may
experience. The yarn 115 is wound up as a package of
yarn on tube 160 at a speed of about 3800 meters per
minute. The POY produced preferably has an elongation
of 55 to 850, preferably 750, and a tenacity of 25 to
40 cN/tex, preferably about 30 cN/tex.
Brief Description of Figures
Figure 1 shows a cross section normal to the
longitudinal axis of the filament through one filament
with the preferred cross sectional shape showing the
dimensions R, F and D, rays R1, R2, reference point C,
tangent reference line R3 and the angle alpha (0();
Figure 2 shows a cross section normal to the
longitudinal axis of the filaments through two adjacent
filaments according to the invention;
Figure 3a is a plan view (to scale) of a two-
segment spinneret capillary cross sectional shape
according to the present invention;
Figure 3b is a plan view (to scale) of a one-
segment spinneret capillary cross sectional shape
according to the present invention;
Figure 4a is a yarn bundle photomicrograph of a
yarn cross section containing 26 filaments produced by
melt spinning in accordance with the present invention
from the spinneret capillary cross sectional shape
Figure 3a.
Figure 4b is a yarn bundle photomicrograph of a
yarn cross section containing 26 filaments produced by
melt spinning in accordance with the present invention
from the spinneret capillary cross sectional shape
Figure 3b.
Figure 5 is a schematic of the apparatus for
carrying out the fully drawn yarn (A) and the POY (B)
spinning processes according to the present invention.
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Test Methods
Water Wicking Test Method: The principle of the method
involves suspending a strip of fabric vertically with
its lower end immersed in water. The height to which
the water rises up the fabric in measured at fixed time
intervals. The fabric samples taken are 300 mm long
and 25 mm wide. The samples are conditioned at a
relative humidity of 850 +/-5o and 20°C +/-2°C for 16
hours. The maximum rise height of the 20°C +/-2°C water
is measured after two minutes. The height is measured
from the surface of the water to the point on the
fabric of maximum water rise. The mean value of three
measurements is reported for each perpendicular fabric
direction.
Fabric Thickness Test Method: The fabric thickness is
the mean distance between upper and lower surfaces of
the material measured under a specified pressure. The
fabric samples are conditioned as for water wicking.
The measuring apparatus used is a Shirley Thickness
Gauge with 50 cm2presser foot. The pressure foot is
allowed to fall under its own momentum onto the fabric.
The measurement is repeated ten times and the mean and
standard deviation are reported to the nearest 0.05 mm.
Examples
Example 1
A first multifilament yarn (Yarn 1A) of 96 dtex
and 26 filaments was spun as a POY using the apparatus
shown schematically in Figure 5 and a spinneret plate
with two segment capillaries according to Fig 3a.
Nylon 66 polymer chip of 49.4 RV, by the formic
acid method, was melted 10 and extruded through a
filter pack 20 and through a spinneret plate 30 with 26
capillaries of the segmented cross sectional shape
shown in Figure 3a at a spinneret temperature of 280°C.
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Next, the emerging filaments 40 were cooled by a
cross flow of air 50, with an air velocity of 0.45
meters per minute. The quench air was directed, with
reference to Fig. 3a, so as to first encounter
confronting lobes 38 of the two segment capillary. The
cooled filaments 60 were converged into a yarn at 70
where an oil and water finish was applied to the
resulting yarn bundle. The converged yarn with the
finish applied was forwarded along Path B in Figure 5.
The yarn was passed through a steam atmosphere
containing interfloor tube 75. The steam treated yarn
85 was intermingled with apparatus 80. The intermingled
yarn 115 was wound up as a package of yarn on tube 160
at a speed of 3800 meters per minute.
The POY produced in this way has a yarn linear
density of 96 decitex, an elongation to break of about
75o and a tenacity of 30 cN/tex. The cross section of
the yarn is shown in Figure 4a.
A second multifilament partially oriented yarn
(Yarn 1B) of 96 dtex and 26 filaments was spun exactly
as the first POY using the apparatus shown
schematically in Figure 5. For Yarn 1B a spinneret
plate with capillaries according to Fig 3b was used.
The elongation and tenacity properties were the same as
for the first POY. The cross section of the Yarn 1B is
shown in Figure 4b.
A comparative multifilament yarn (Yarn 1C) of 96
dtex and 26 filaments was spun in exactly the same way
as the first yarn, except for replacing the spinneret
plate with one having 26 "circular cross sectional"
shaped capillaries.
All samples, 1A and 1B (yarns of the invention)
and 1C (a circular cross section comparative yarn) were
separately 8-plied and then air jet textured (AJT)
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using a HEBERLEIN HEMAJET (Registered Trade Mark) to
make a 730 decitex by 208 filament (8 x 26 filaments)
textured yarn. These textured yarns were 2-plied and
knitted into a "full cardigan structure" and tested for
thermal transmittance.
The thermal transmittance test method was
essentially that of ASTM D1518-85 (as reapproved 1990).
This method measures the time rate of heat transfer
from a warm, dry, constant-temperature, horizontal
flat-plate up through a layer of the knitted cardigan
test material to a relatively calm, cool atmosphere.
Thermal resistance was measured and the thermal
insulation or CLO value calculated. The "CLO" is a
unit of "clothing thermal resistance" in ASTM D1518 and
equal to 0.155 (°C m2W-1) . The base temperature was 25°C
(T1) and the head plate, temperature was 35°C (T2) .
There was minimal pressure applied to the cardigan
knit, 260 Nnl2 during the test procedure. Each sample
was tested three times to give the mean result reported
in Table 1 below.
These test results, reported in Table 1, show a
13-15o increase in thermal resistance for the preferred
open hollow cross section versus the circular cross
section yarn in a knit construction. Similarly, the CLO
values for the open hollow cross section versus the
circular cross section yarn in a knit construction
increased by 13 - 150. Clearly, the open hollow
filament yarn in the knit construction tested is a
better thermal insulator versus the circular filament
yarn.
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Table 1.
Yarn used in Thermal resistance CLO value
cardigan knit Meter2 C W-1 x Meters C W-
(103) 1/ (0.155)
ASTM D1518-85
Yarn 1A (2 x 103.7 0.67
730f208)
invention cross
section using two
segment spinneret
Yarn 1B (2 x 105.0 0.68
730f208)
invention cross
section using one
segment spinneret
Yarn 1C (2 x 91.5 0.59
730f208)
"circular" cross
section
Example 2
POY samples from Example 1, Yarn 1A and
comparative Yarn 1C, both 96 decitex and 26 filaments
as spun, were false-twist textured (FTT) at 600 meters
per minute on a DCS 1200 texturing machine. The
primary heater of the texturing machine was 220°C, no
secondary heater was used. A draw-textured yarn of 78
decitex and 26 filaments (78f26) was prepared with the
texturing machine's 6 mm solid ceramic discs configured
to 1/7/1 smooth/working/smooth. The 78f26 yarns were
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circular knitted into 28 gauge plain interlock fabrics,
scoured, dyed and heat set. Fabric samples of 300 mm
by 25 mm were taken for water wicking tests. These
samples were hung vertically into a water bath and the
vertical rise of the water was measured after two
minutes. The mean of three samples is given in Table
2. The fabrics constructed from yarns having filaments
of the preferred cross section showed a water wicking
advantage over identically constructed fabrics from
yarns of circular filament cross section. This
advantage is at least a 2-fold improvement in water
wicking capability.
Table 2.
Textured yarn used Vertical rise in Vertical rise
in circular knit mm (fabric in in mm (fabric
longest direction) in shortest
direction)
78f26 comparative 1.5 0
circular cross
section (Yarn 1C)
false twist
textured yarn
78f26 invention 3.7 2.7
cross section (Yarn
1A) false twist
textured yarn
Example 3
A drawn yarn of 192 decitex and 52 filaments was
spun with the apparatus of Figure 5 and using the
spinneret plate with 52 capillaries of the cross
sectional shape of Figure 3a. Nylon 66 polymer of 49.4
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RV (by the formic acid method) was melted 10, extruded
through a polymer filter pack 20 and then through the
above spinneret 30 maintained at a temperature of
280°C. The extruded filaments 40 were cooled by a
cross flow of air 50 flowing at 0.4 meters per minute.
The cross flow of air 50 was directed to first
encounter confronting lobes 38 of the two segment
capillary shown in Fig. 3a. The cooled filaments were
converged into a yarn bundle 60 with oil and water
application and forwarded along alternative Path A.
The yarn was intermingled with an air jet 80, as
typically practised in the art. The intermingled yarn
90 was then fed via feed roll 92 and associated
separator roll (making several wraps on the roll to
prevent slipping) to a second godet 94 and associated
separator roll (the draw roll), moving at a surface
speed 80o greater than that of the feed roll 92'. The
intermingled yarn bundle 90 was drawn, by a total
factor of 1.8, reducing the overall yarn titer. The
drawn yarn 100 was treated by a steam jet 110 to set
the draw and to relax the yarn. The relaxed yarn bundle
120 was passed through a second interlace jet 130 and
then the yarn 140 was wound up on a tube 150 at a speed
of 3800 meters per minute. This process provided cakes
of fully drawn yarn (FDY) with a yarn linear density of
192 decitex, a breaking elongation of 42.8, tenacity
of 41 cN/tex. The yarn in dry form had an RV of 50.3
by the formic acid method. Filaments of this 52
filament yarn have a cross sectional shape normal to
the longitudinal axis which is substantially similar to
those filaments shown in Figure 4a.
This yarn, Yarn 3A, was used as the weft yarn of a
woven fabric of 3/1 twill weave where the warp yarns
were 78 decitex (51 circular filaments). Weaving and
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fabric finishing details are given in Table 3. As a
comparative example, a fully drawn yarn of 192 decitex
and 52 filaments was spun in exactly the same way as
above but using a spinneret plate with "circular cross
section" capillaries, this yarn was called Yarn 3B. A
second fabric sample was woven using Yarn 3B in the
weft as above. Weaving and fabric finishing details
are given in Table 3. The two fabrics were finished
identically in greige, dyed and heat-set form. From
each fabric specimen (greige, dyed and heat-set) 10
samples of 75 square millimeters were cut. These
samples were measured for fabric thickness in the same
way using a micrometer. The results of the fabric
thickness measurements (mean of 10 measurements) are
provided in Table 3. The fabrics containing the
preferred cross section filaments in the weft were
thicker than that woven of entirely circular cross
section filaments in the warp and weft. As a result,
the woven fabrics having the preferred cross section
filaments in the weft provided a lower density fabric
with a lightweight aesthetic.
m .., ~.. i ,-, ~
Greige Greige Dyed Dyed Heatset Heatset
fabric fabric fabric fabric fabric fabric
Yarn Yarn Yarn Yarn Yarn Yarn
3B 3A 3B 3A 3B 3A
Warp ends 57.5 58.2 61.3 62.2 61.5 61.6
per cm
x
weft x x x x x x
picks per 38.8 39.7 40 39.8 41 41
cm
Woven 0.22 0.24 0.20 0.22 0.20 0.21
fabric
thickness
millimete
rs
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The above embodiments have been described by way of
example only. Many other embodiments of the filaments,
yarns, spinnerets and processes according to the
present invention will be apparent to the skilled
reader.
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