Note: Descriptions are shown in the official language in which they were submitted.
3~6
The invention relates to a textured polyester yarn
latently having variation in dyeability along its length so
that a knitted or woven fabric from the yarn can have a favorable
color tone of a unique sprinkly colored effect when being
dyed. The invention also relates to a process for the produc-
tion of such a yarn.
DESCRIPTION OF THE PRIOR ART
Polyester multiilament yarns are known in which the
individual filaments contain thick sections having compara-
tively lower molecular orientation and thin portions having
- comparatively higher molecular orientation. ~owever, the
known yarns are not practically useful due to the fact that it
is difficult to subject them to false-twisting or dyeing.
This is because these yarns are usually produced by stretching
an undrawn yarn of polyester filaments having a birefringence
of 0.5 to 10x10 3 and, thus, they become fragile in the sec-
tions having lower molecular orientation when the sections have
been crystallized.
We have already proposed, in Japanese Patent Applica-
tion No. 48-70954 ~automatically laid open specification No.
50-18717) and in Japanese Patent Application No. 48-70955
~automatically laid open specification No. 50-18718~, a process
for the production of a yarn composed of polyester multifila-
ments having thick and thin sections from a highly oriented
polyester undrawn yarn. We have further proposed, in Japanese
Patent Application No. 48-70953 ~automatically laid open speci-
fication No. 50-18716) and in Japanese Patent Application No.
48-135236 ~automatically laid open specification No. 50-88356)~
a process for the production o~ a textured polyester yarn having
variation in dyeability along its length by false twisting a yarn
such as obtained by the process proposed in Japanese Patent
Application No. 48-70953.
However, the process of Japanese Patent Application
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~.~51~366
No. 48-135263 is characterized by false twisting a material
yarn under conditions such that the thick sections of the
material yarn are not stretched and, thus, produces a yarn
generally having an Uster evenness value of more than
1.0%. Thus, the yarn obtained by this process has such
defects that a knitted or woven fabric from the yarn tends
to have too large a difference in color shades when being
dyed and to have a hard, rough feel due to the retension
of many thick sections where the filaments have been
crimped without being stretched.
Also, the production of a false twisted yarn from
an undrawn yarn of polyester multifilaments having thick
and thln sections is disclosed, for example, in Japanese
Patent Publication No. 51-11218 and Japanese Patent Appli-
cation No.- 47-105092 (automatically laid-open specification
No. 49-62718). However, these yarns also have the defects
as mentioned above.
Further, it is well known that not-untwisted portions
are produced in the conventionally false twisted yarns.
. .
Since the not-untwisted portions are usually recognized as
a defect on the fabric knitted or woven from the yarn
having such portions, much effort has been exerted in
conventional false-twisting to avoid the production of
such not untwisted portions in the false twisted yarns.
OBJECT OF THE INVENTION
The present invention makes it possible to remove
the defects of the te~tured polyester yarns as mentioned
above. The present invention also makes it possible to
advantageously utilize the production of the not-untwisted
portions which has been recognized as a defect in conventional
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~L~S~366
false-t~isting.
Thus, it is an object of the invention to ~ovide a
textured polyester multifilament yarn in which the difference
in thickness along the yarn length is comparatively reduced by
randomly distributing the thick sections of the individual
filaments in the yarn, ~n w~ich yarn not-untwisted portions
having genuine twists of a fixed direction are randomly re-
tained along the yarn length and which yarn can give a favor-
able color tone of a sprinkly colored effect to a knitted or
woven fabric from the yarn when being dyed.
Another object of the invention is to provide a tex-
tured polyester multifilament yarn in which the thickness is
not even but the difference in thickness along -the ~arn length
is not too large and which can produce a desirable feel in
hand on a fabric which is knitted or woven from the yarn.
A further object of the invention is to provide a
process for the production of the textured polyester multi-
filament yarn as mentioned above.
In a preferred embodiment of the present invention
2Q there is provided a textured polyester yarn having improved
variation in dyeability along its length, which is composed of
a plurality of individual filaments each having thick and thin
sections randomly distributed along the filament axis and
which has an Uster evenness value of l.0 to lO.0~, a T index
as defined in the specification of 3 to 30, a variation in re-
flected light intensity as defined in the specification of
+0.15 to 0.80 and a broken filament countof not more than lO0
-
per 2,000 m of the yarn length.
In a further preferred embodiment of the ~esent inven-
tion there is provided a process for the production of a tex-
_ 4
~t~5a~3~i~
tured polyester yarn, compr~sing false twisting a polyester
yarn composed of a plurality of individual filaments each
having thick and thin sections randomly distri~uted along the
filament axis, in which the thick sections have a birefrin-
gence of 15 to 80 x 10 3 and the thin sections have a ~ire-
fringence of 90 to 200 x 10 3, at a temperature o~ 180 to 230
C and under a twisting tension of 0.05 to 0.8 g/d, with a
variation with respect to the average twisting tension of +5
to +20% and an untwisting tension of 0.1 to 0.8 g/d.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an Uster evenness chart showing the varia-
tion in t~ickness of a textured polyester multifilament yarn
according to the invention along the yarn length.
Fig. 2 is a chart of a textured polyester multifila-
ment yarn according to the invention along the yarn length
prepared for determining its T index.
Fig. 3 is an enlarged view of the not-untwisted and
untwisted portions of a textured polyester multifilament yarn
according to the invention.
Fig. 4 is an enlarged scllematical view of the
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~t~5(~3~6
untwisted portion of the yarn shown in Fig. 3, which has
been dyed.
Fig. S is a schematical view of an example of the
distribution of skip dents on the surface of a woven
fabric in which a textured polyester multifilament yarn
according to the invention is employed as a weft.
Fig. 6 lS a front view of a device usable for the
dete~Nnation of the twist retention coefficient of the not
untwisted portions of a yarn.
DETAILED DESCRIPTION OF THE INVENTION
The invention provides a textured polyester yarn
having improved variation in dyeability along its length,
which is composed of a plurality of individual filaments
each having thick and thin sections randomly distributed
along the filament axis and which has an Uster evenness
value of 1.0 to 10.0%, a T index of 3 to 30, a variation
in reflected light intensity in a continuous dyeing test
of +0.15 to +0~80 and a broken filament count of not more
than 100 per 2,000 m. The yarn of the invention preferably
has not-untwisted portions containing genuine twists of a
fixed direction intermittently retained at random along
its length.
In the yarn of the invention, it is important that
it has an Uster evenness value of 1.0 to 10.0%, preferably
1.5 to 8.0% and a T index of 3 to 30, preferably 5 to 25.
Where the Uster evenness value is less than 1.0% and the T
index is less than 3, the amount of the deep colored
portions of the yarn when being dyed is disadvantageously
limited, and where the Uster evenness value is more than
10% and the T index is more than 30, the amount of the
-- 5 --
~051~)3~G
deep colored portions of the yarn when being dyed becomes
too large. Thus, in both cases, the yarn has an inferior
balance of the deep colored portions to the light colored
portions when being dyed and, therefore, can no-t produce a
knitted or woven fabric capable of having a desirable
color tone of a sprinkly colored effect.
The Uster evenness value and the T index both are
characteristic values indicating the variation in the
thickness of a multifilament yarn and may be determined as
follows.
Determination of Uster Evenness ~alue
The Uster evenness value may be determined according
to the ASTM methods D 1425-67. That is, using a commercially
available Uster Evenness Tester, an Uster evenness curve
with respect to a yarn being false twisted on a false-
-twisting apparatus at a yarn speed of 4 m/min and at a
spindle rotation of about 1,500 r.p.m. is drawn on a chart
at a chart speed of 25 cm/min as shown in Fig. 1. Then,
from the chart obtained for 3 minutes, the Uster evenness
value is read by means of an integrato~. The Uster evenness
value is recorded as the average of at least fifteen
measurements, at at least five points in three zones, the
- zones dividing the length of the yarn composing one package
approximately equally.
Determination of T Index
An Uster evenness curve is drawn as mentioned above
on a standard chart marked off from 0 to 100% so that the
portion of the curve corresponding to the thinnest sections
of the yarn coincides with the 0% base line A' as shown in
Fig. 2. Then, the area between the curve and the 0% base
~)S0366
line A'with respect to a portion corresponding to a yarn
length of 8 m is determined. The T index of 1 corresponds
to the area of 0.333 cm2.
In the yarn of the invention, it is also important
that it has a variation (~ L/L) in reflected light intensity,
in a continuous dyeing test as mentioned hereinafter, of
+0.15 to +0.80, preferably ~0.20 to +0.60~ Where the
variation in reflected light intensity is less than +0.15,
the yarn has too small a difference in color shades when
dyed and where the variation in reflected light intensity
is more than ~0.80, the yarn has too large a difference in
color shades. Thus, in either case, the yarn can not
produce a knitted or woven fabric capable of having a
desirable color tone of a sprinkly colored effect.
Continuous Dyeing Test
The method as disclosed in U.S. Patent No. 3,945,181
may be employed. Light is irradiated to a multifilament
yarn being continuously dyed while running, the reflected
light is measured by a photocell to detect the variation
in shade of color as the reflected light intensity and the
variation is recorded on a paper as an L value (brightness
value) curve. From the L value curve, an average value L
and its amplitude ~ L are determined as the average of a
portion corresponding to a yarn length of 4 m. The measure-
ment is repeated with respect to two or three differentportions of the yarn.
However, it should be noted that since the portional
difference in the configuration of the yarn is large, the
variation in color shades can not be detected merely by
measuring the reflected light intensity. Thus, the variation
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~oso366
in color shades of the yarn can be detected, without being
affected by the difference in the configuration of the
yarn, by dividing the reflected liyht into two by means of
a half mirror and detecting, by means of two photocells,
one of the two divided lights as the visible light intensity
through a visible range filter and the other as the infrared
light intensity through an infrared range filter. Then,
the ratio of the two intensities is put out as the logarithm
thereof.
The yarn to be tested is run at a speed of 3 m/min
while being subjected to a tension of about 0.6 g/d,
treated in water at 70C for 3 minutes and continuously
introduced into a dye bath maintained at 90C. The dye
bath contains 20 g/~ of Diacelliton Fast Blue B ~C.I.
Disperse Blue 3) and 3 g/æ of a ~onionic dispersing
agent. The yarn is dyed for 3 minutes, washed with water
at 70C for 3 minutes and then dried. The yarn is then
subjected to the measurement as mentioned above.
In the yarn of the invention, the broken filament
count is preferably not more than lO0, more preferably not
more than 80, per a 2,000 m length. Where the broken
filament count is more than lO0 per 2,000 m, the yarn has
inferior processability and, thus, it becomes difficult to
knit the yarn lnto a fabric. Where the yarn is to be
woven, it is preferred that the broken filament count of
the yarn is not more than 80 per 2,000 m because troubles
such as yarn breakage and the like are reduced upon warping
and also the yarn has superior processability ln sizing or
twisting. The broken filament count may be measured by
means of a device such a disclosed in Japanese Patent
-- 8 --
~(~S0366
Publication No. 49-20813.
In general, a conventional false twisted yarn has a
broken filament count of 0 to 10 per a 2,000 m length and
a conventional spun yarn has a broken filament count of
13,000 to 100,000 per a 2,000 m length, if they are counted
by the device as used for the measurement of the broken
filament count of a yarn of the invention.
The individual filaments composing the textured
polyester yarn of the invention have a distribution of
increased and decreased cross-sectional areas along their
length. The ratio in cross-sectional area of the thickest
sections to the thinnest sections is preferably 1.4 to
2.7. It is also preferable that the yarn has more sections
having a medium thickness between those of the thickest
and the thinnest sections, than those of the material yarn
from which the textured yarn has been produced.
Further, it is particularly preferable that in the
textured polyester yarn of the invention, not less than 20
per 100 m of yarn length of not untwisted portions contain-
ing genuihe twists of a fixed direction are retained
intermittently and randomly along the yarn length.
- As shown in Fig. 3, the not untwisted portion 1 of
the yarn possesses a sufficient number of twists wherein
the number of twists is one half or more of the number of
twists imparted in the false-twisting, while the untwisted
portion 2 has a configuration similar than that of a
conventional false twisted yarn. In the untwisted portion,
each of the filaments which compose the yarn has crimps to
give bulkiness to the portion. Although the untwisted
portion 2 should have twists of the opposite direction
503ti6
having a number of twists correspondlng to that of the
not-untwisted portion, said opposite twists can not be
seen. In the not-untwis-ted portions of the yarn, the
direction of the twists is fixed and is the same as the
twisting direction in the false-twisting. The not-untwisted
portions have a short length of 1 to 150 mm, preferably 1
to 50 mm, and 2~ to 1,500 such portions exist per 100 m of
yarn length.
The yarn of the invention has a large twist retention
-10 coefficient, such as not les-s than 70, as measured by the
measuring method as mentioned below, and the twists of the
yarn are maintained under a tension of 0.1 to 0.5 g/d.
Thus, the yarn can maintain the not-untwisted portions of
the genuine twists, even after it has been subjected to
tensioning forces during the knitting or weaving and the
dyeing.
Measurement of Twlst Retention Coefficient
The twist retention coefficient of the not-untwisted
portion may be measured using the measuring device as
shown in Fig. 6.
A not-untwisted portion of a yarn 8 to be tested is
placed within the visible range of a binocular microscope
5 and one end of the yarn is fixed by a clamp 6. The yarn
is held horizontally through a pulley 9 and an initial
load 7 of 0.1 g/d is added to the other end of the yarn
hanging downward from the pulley. Then, the number of
twists Tl per 1 cm is read by means of the microscope 5
Thereafter-, the initial load is removed and a measuring
load of 0.5 g/d is added and maintained for 30 seconds.
Then, the initial load is again added in place oE the
- 10 -
1~5()3~
measuring load and maintained Eor 30 seconds and, then,
the number of twists T2 per 1 cm is read by means of the
microscope 5. The twist retention coefficient P may thus
be calculated by the equation:
P = T2 x 100
Thus, it should be appreciated that the twist
retention coefficient indicates the extent of retention of
twists in a yarn having genuine tWlsts after the yarn has
been elongated under a certain load and the length of the
yarn has then been restored. That is, the.twist retention
coefficient indicates the degree of resistence to the
disappearence of the twists of the yarn having genuine
twists under a tensioning force.
In order to maintain the coherent configuration of
the yarn in a final textile article, such as a knitted or
woven and dyed fabric, and to produce a fancy effect on
the final textile article, the configuration giving the
coherency to the yarn must not be decomposed under tensions
to which the.yarn is subjected during the processing
stages for producing the final article from the yarn. It
has been recognized that the largest tension to which the
yarn is subjected during the production of a fabric is a
tension of 0.3 to 0.4 g/d such as instantaneously and
repeatedly imparted during weaving.
The yarn of the invention has a twist retension
coefficient of not less than 70, generally 80 to 90, in
the not-untwisted portions. Thus, the yarn of the invention
has very high retentivity of twists and, therefore, can
105~6G
produce a desirable fancy effect in the final articles
producedfrom the yarn.
Polyester, which composes the textured yarn of the
invention, may be a homopolymer of ethylene terephthalate
or a copolymer of ethylene terephthalate with a copoly-
merizable monomer containing not less than 80.0 mol ~ of
ethylene terephthala-te units. As the copolymerizable
monomer, one or more monomers selected from dibasic acids,
such as adipic acid, sebacic acid, isophthalic acid and
diphenyldicarboxylic acid, hydroxy acid such as hydroxybenzoic
acid, and glycols such as diethylene glycol, propylene
glycol, neopentyl glycol, pentaerythritol and polyethylene
glycole monomethyl ether, may be used.
The textured polyester multifilament yarn of the
invention as mentioned hereinbefore can be produced by
false twisting a polyester yarn composed of a plurality of
individual filaments each having variation in cross-sectional
area along its length.
In the material yarn to be employed in the false-
-twisting, the individual filaments should have a birefringence
of 15 to 80xlO 3, preferably 25 to 80xlO 3, in the thick
sections and a birefringence of 90 to 200xlO 3 in the thin
sections in view of the variation in dyeability of tha
yarn to be obtained and of the processability in the
false-twisting.
Where the thick sections have a birefringence of
less than 15xlO 3, yarn breakage frequently occurs and
many broken filaments are produced in the false-twisting
process. If a yarn having thick sections of a birefringence
of not less than 15xlO is employed, the broken filament
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~(~SID366
count produced in the false-twisting is advan-tageously
reduced and, thus, it is preferable to employ a yarn
having thick sections of a birefringence of not less than
25xlO 3 in the case where a yarn of particularly limited
broken filament count is to be produced. In turn, where
the thick sections have a birefringence of more than
80xlO 3, the variation in dyeability of the obtained yarn
- is disadvantageously limited to such an extent that a
desirable difference in color shades can not be obtained
when the yarn is dyed.
Further, if a material yarn of individual filaments
is employed wherein the ratio in cross-sectional area of
the thick sections to the thin sections is less than 1.4,
the variation in thickness of the obtained yarn is not
sufficient and too small a difference in color shades is
obtained when the obtained yarn is dyed. Also, if a
material yarn of individual filaments is employed wherein
the ratio in cross-sectional area of the thick sections to
the thin sections is more than 2.7, it is difficult to
obtain a desired textured yarn. Thus, in the false-twisting
- according to the invention, it is preferable to employ, as
a material, a yarn of individual filaments wherein the
- ratio in cross-sectional area of the thick sections to the
thin sections is from 1.4 to 2.7, more preferably from 1.4
to 2.25. In the case where the filaments have a circular
cross-section, this ratio of 1~4 to 2.7 corresponds to a
ratio in diameter of the thick sections to the thin sections
of 1.2 to 1.65. Furthermore, the lengths of the thick
sections of the filaments of the material yarn are preferably
30 not more than 100 mm, more preferably not more than 70 mm,
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1~3S~3~6
since a desirable textured yarn can not be obtained if the
lengths and spacings of the th:ick sections of the individual
filaments are-too large in the material yarn.
The extent of the variation in thickness of a
multifilament yarn can not be indicated by only the ratio
in cross-sectional area of the component filaments or the
birefringence and, thus, the extent of the variation .in
thickness of such a yarn should also be noted from the
point of view of the e~enness in thickness which may be
known from an evenness curve such as the Uster evenness
curve as hereinbefore mentioned. Thus, in ordèr to obtain
a textured yarn capable of producing a desirable color
tone of a sprinkly colored effect on a fabric produced
from the yarn, the material yarn to be fed to the false-
-twisting should preferably have an Uster evenness value
. of 4.0 to 15~, more preferably 6 to 13%, and a T index of
20 to 90, more preferably 25 to 80.
. The above-mentioned material polyester yarn may be
ob.tained, as described in Japanese Patent Application No.
48-70955 hereinbefore mentioned, by non-uniformly drawing a
highly oriented polyester undrawn yarn having a birefringence
of 15 to 60xlO 3 on a conventional draw-twister at a draw ratio
of 1.1 to 2.7, by means of a hot pin of a temperature ranging
from ~Tg-50)C to (Tg~50)C~ wherein Tg is the glassy-transition
temperature of the yarn.
The false-twisting according to the invention may
be carried out at a temperature of 180 to 230C and under
a twisting tension of 0.05 to 0.8 g/d, with a variation
with respect to the average twisting tension of +5 to ~20%
and an untwisting tension of 0.1 to 0.8 g/d. Preferably,
the false-twisting is carried out on a single heater type
- 14 -
~)5~3~;6
or double heater type false-twisting apparatus under the
following conditions: a feed percentage (feed speed minus
delivery speed divided by de]ivery speed x lO0) of -6 to -20~;
a twisting tension of 0.05 to 0.8 g/d, preferably 0.08 to 0.5
g~d; an untwisting tension of 0.1 to ~.8 g/d, preferably 0.15
to 0.6 g/d; a variation in twisting tension with respect to
the average twisting tension of +5 to +20~; a heater temper-
ature of 180 to 230C, and, a number of twists in T/M of
23,000 ~- to 27,000 ~ , wherein D is the total denier of the
yarn and ~ is the specific gravity of the yarn. In the
false-twistlng operation, the distribution and the length of
the thick and thin sections of the component filaments of
the obtained yarn, and the distribution and length of the not
untwisted portions of the obtained yarn can be controlled by
suitably combining the properties of the employed material
yarn with the false-twisting conditions within the above-
mentioned ranges. The twisting tension refers to a tension
before spindle and the untwisting tension refers to a tension
after spindle.
Among the above-mentioned false-twisting conditions,
the temperature, the tension and the number of twists a~e
very important and, particularly, of these, the tension is
the most important. If the twisting tension is less than
0.05 g~d, it is difficult to carry out the false-twisting
stably. Further, since the false-twisting can be carried
out more stably under a tension slightly higher than the
lower limit of the twisting tension, it is preferabl~ to
carry out the false-twisting under a twisting tension of
not less than 0.08 g/d. If the twisting tension is more
~1)51C)3G6
than 0.80 g/d, the variation in thcikness of the component
filaments of the obtained yarn becomes too small and,
thus, too small a difference in color shades is obtained
when the yarn is dyed. In order to obtain a textured yarn
capable of producing a desirable color tone of a sprinkly
colored effect on a fabric produced from the yarn, it is
preferable to carry out the false-twisting under a tension
of not more than 0.5 g/d.
However, a fabric having a desirable color tone of
a sprinkly colored effect and a favorable feel can not be
obtained from the yarn produced merely by employing the
twisting tension falling within the above-discussed range.
Thus, it is very important to control the variation in
twisting tension within the range of +5 to +20% with
respect to the average twisting tension. The variation in
twisting tension can be controlled by positively vibrating
the yarn at the false-twisting zone, by regulating the
properties of the material yarn by changing the yarn
speed, ratio or temperature in the-drawing or by precisely
regulating the speeds of the feed and delivery rollers of
the false~twisting apparatus employed. The variation in
twisting tension may be measured as follows.
Measurement of Variation in Twisting Tension
The variàtion in the tension imparted to the yarn
is recorded on a paper using an oscillograph recordable to
a value of about 100 Hz by insertlng a tensiometer detectable
to a value of about 150 Hz into the twisting zone of
the false-twlsing apparatus employed. Then, the variation
in twisting tension with respect to the average twisting
tension +A/T ~ 100 (%) is calculated from the amplitude A
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~503~6
and average tension T of the recorded variation.
In the textured yarn of the invention, the thick
sections to be deeply dyed and thin sections to be lightly
dyed of the component filaments are randomly distributed
along the yarn length. Thus, the yarn produces a desirable
and unique color tone of a sprinkly colored effect in a
fabric produced from the yarn when the fabric is dyed. In
addition, in the tex-tured yarn of the invention, not
untwisted portions having retained genuine twists randomly
exist along the yarn length and these portions can also be
deeply dyed to constitute a part of the deeply dyed portions
of a fabric produced from the yarn. Thus, the existence
of these portions can produce a further desirable color
tone of a sprinkly colored effect.
Fig. 4 shows a state of-the component filaments in
the untwisted portion of the yarn as shown in Fig. 3,
which has been dyed at 80C for one hour in a dye bath
containing 3~ o.w.f. of Dianix Navy Blue ER-FS (C.I.
Disperse Blue 142) and 10% o.w.f. of an ester of benzoic
acid at a liquor ratio of 100:1. From the drawing, it
should be noted that deeply dyed sections 3 and lightly
dyed sections 4 exist randomly in the yarn.
The not-untwisted portions of the textured yarn of
the invention are retained after the yarn is knitted or
woven into a fabric and, thus, these portions on the
fabric, being thinner than the ramining portions of the
yarn, ~ive a unique appearence to the fabric. For example,
the not-untwisted portions produce random skip dents on
the surface of the fabric. After the fabric is dyed and
finished, the skip dents are not very conspicuous due to
17 -
105036~
the crimping of the yarn. It is possible, if desirable,
to make the skip dents completely inconspicuous by suffici-
ently crumpling the fabric during the dying or finishing.
- Further, the not untwisted portions are highly
coherent and, thereEore, the state of reflec-tion of light
from the portions in a fabric diEfers from that rom the
untwisted portions having a configuration similar to that
of a conventional false twisted yarn. Thus, in this
respect, a fabric of a unique apparence, wherein portions
of dlfferent gloss are scattered, can be obtained from the
yarn of the invention.
In the case where a fancy effect as mentioned above
is to be produced on a fabric made from the yarn of the
invention, it is desirable that the length of the not
untwisted portions be small and that the number of these
portions be large. For example, at least 500 of the
not-untwisted portions are desirable in 1 m2 of the abric.
Desirable embodiments of the fabric obtainable from
the textured polyester yarn of the invention are illustrated
below.
The first embodiment of such a fabric is a knitted
or woven fabric having a color tone of a sprinkly colored
effect and comprising a textured polyester multifilament
yarn having deeply dyed and lightly dyed portions at
random along its length, and a broken filament count of
not more than 100 per 2,000 m. In the fabric, the rate of
the deeply dyed portions as defined hereinafter is 30 to
50% and the lengths of the continuous deeply dyed portions
are in a range of 0.25 to 8 cm.
The fabric may be obtained by weaving or knitting
- 18 -
lOS~66
the textured polyester yarn of -the invention, using it as
a warp and/or weft, and dying the knitted or woven fabric.
The rate of the deeply dyed portions of the dyed fabric is
suitably 30 to 50~, preferably 38 to 45~, and the lengths
of the continuous deeply dyed portions are suitably in a
range of 0.25 to 8 cm, preferably 1 to 5 cm. The average
length of the continuous deeply dyed portions is suitably
about 2.5 cm. Thus, the term "a fabric of a suitable or
favorable color tone of a sprinkly dyed effect" as used
herein may refer to, for example, a fabric having a rate
of the deeply dyed portions of 30 to 50% and lengths of
the continous deeply dyed portions falling within a range
of 0.25 to 8 cm.
~ The above-mentioned rate of the deeply dyed portions
of a fabric may be defined as follows.
In the case of a woven fabric, the rate of the
deeply dyed portions is defined as the rate of the number
of floating yarn units of a relative L value ratio of not
less than 1.35 to the totàl number of floating yarn units
existing in an area of 10 cm x 10 cm of the fabric. The
floating yarn unit refers to a unit of the warp or weft
- yarn in a section where the yarn composing the fabric
comes out to the front surface and again goes into the
fabric. The relative L value ratio refers to a ratio in L
value of the lightly dyed portions to the deeply dyed
portions.
In the case of a knitted fabric, the rate of the
deeply dyed por-tions is defined as the rate of the number
of loops of a relative L value ratio of not less than 1.35
to the total number of loops existing in an area of 10 cm x 10 cm
-- 19 --
~503~;~
of the fabric.
The number of floating yarn units or loops may
be determined by actually counting the number using
a magnifying glass. The length of the continous
deeply dyed portion may be determined by actually
measuring the length of a section where the deeply
dyed floating yarn units or the deeply dyed loops
continuously exist.
The second desirable embodiment of the fabric
obtainable from the textured polyester yarn of the
invention is a woven fabric comprising a textured
polyester multifilament yarn having a broken filament
count of not more than 100 per 2,000 m. In this fabric
both of the friction coefficients in the warp and weft
directlons are not more than 1.2, the ratio of the
higher friction coefficient to the lower friction
coefficiènt-is not more than 1.5 in both directions and
the specific volume is not less than 2.0 cm3/g.
The woven fabric does not a very large broken
- 20 filament count and, thus, has a soft and smooth feel.
It should be noted, however, that the textured polyester
yarn of the invention may be used in a knitted or woven
fabrlc as a blend with another type yarn. In such a
case, the measurement of the deeply dyed portions as
mentioned above may be carried out against only the
yarn of the invention. The friction coefficient and
the specific volume may be determined as follows.
Determination of Friction Coefficient
A sample of a fabric to be tested is fixedly placed
on a plain plate horizontally placed. Another sample of
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~OS03~6
the fabric is fixed to a rectangular plain plate of a size
of 5 cm x 7 cm. The rectangular plate is then placed upon
the plain plate so as to bring the two samples into contact
with each other. A vertical load of 300 y is added to the
rectangular plate and the rectangular plate is moved at a
speed of 4.8 cm/min in the direction of the length thereof.
Then, the maximum value of the moving resistance force is
measured as a friction force using a stress measuring
device. The frIction coefficient is calculated as the
ratio of the friction force to the vertical load. The
friction coefficient of the warp direction is determined
by placing the two samples so that the warp direction of
one sample coincides with the warp direction of the after
sample and moving the rectangular plate in the warp direction.
The friction coefficient of the weft direction is simllarly
determined by moving the rectangular plate in the weft
direction. The samples should be previously scored and
conditioned in an atmosphere of 20C + 5C and 65% + 10%
R.H. and the measurement should be carried out in said
atmosphere.
Determination of Specific Volume
In an atmosphere as mentioned above, the thickness
of a sample of a fabric to be tested is measured using a
micrometer gauge. In the measuring, a load of 1~ g per an
area of 2 cm is added to the sample. The specific volume
is calculated as a volume per unit weight. The weight of
the sample may be measured using a chemical balance. The
volume may be calculated by the thickness and the area of
the sample.
The invention will be further illustrated by the
- 21 -
~(~5~366
following Examples wherein the double refrackions were
measured by a polarizing microscope.
Example 1
A thick and thin yarn was prepared by non-uniformly
drawing at a draw ratio of 1.3~ a polyethylene terephthalate
undrawn yarn composed of 48 filaments having a birefingence
of 41.6 ~ 10 . The individual filaments of the obtained
thick and thin yarn had thick s~ctions of a birefringence
of 42 x 10 3 and thin sections of a birefringence of
10 108 x 10 3, the ratio in cross-sectional area of the
thickest sections to the thinnest sections was 1~7, the
average fineness of the obtained yarn was 155 denier and
the Uster evenness value of the yarn was 11.0%.
The thick and thin yarn was then false twisted on a
false-twisting machine at a speed of 400 m/min and at a
temperature of 210C. The false-twisting machine employed
was of the type wherein a hot plate type heater having a
length of 1.5 m and an external friction type twister
capable of feeding the yarn were provided between a feed
- 20 roller having a nip with an apron type roller and a delivery
roller of the same construction as the feed roller. The
twisting tension to which the yarn was subjected was 36 g,
i.e. 0.23 g/d, and the variation in twisting tension was
+3.5 g, which corresponded to +9.7~ with respect to the
average twisting tension. The number of twists imparted
was 2,350 T/M and the broken filament count observed in
the processed yarn was 6 per 2,0~0 m.
The ratio of the cross-sectional area of the thickest
sections to that of the thinnest sections of the individual
filaments composing the false twisted yarn was about 1.7,
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~1~50366
the Uster evenness value of the yarn was 2.5% and the T
index of the yarn was 11. The variation in dyeability of
the yarn, determined by the method as hereinbefore mentioned,
was a ~L/L of +0.33 and an L of 24% and, thus, the yarn
was proved to have sufficient variation in dyeability.
A fabric woven from this yarn was dyed using a dye
having tendency to result in uneven dyeing. The dyed
fabric had a favorable color tone of a sprinkly colored
effect.
Example 2
A thick and thin yarn was prepared from a polyethylene
terephthalate undrawn yarn composed of 30 filaments having
a birefringence of 37 x 10 3. The individual filaments of
the obtained yarn had thick sections of a birefringence of
38 x 10 3 and thin sections of a birefringence of 115 x 10 3,
and the ratio of the diameter of the thickest sections to
that of the thinnest sections was 1.4.
- The thick and thin yarn was then drawn at various
draw ratios to obtain yarns having the various Uster
evenness values and T index values indicated in Table 1
below. The yarns were then false twisted at a temperature
of 210C and the properties of the false twisted yarns
were determined. The results are shown in the table. Run
Nos. 1 and 6 are given for comparison purposes for clarify-
ing the effects of the invention.
- 23 -
~()S~)3~6
. .... ..... ......... ,. ~
~ ~ ~Ln o u~ o Ln oo ~ n ~ ~ ~
~ + I ~ O
+ I ~
Ln o o~ o :4 o ~ o o~ o
Ln
. ~1 ~r ~~1 Ln ~ rJ~l ,4 r~ .
,-1 +1+l~ i .~
Ln Ln O ~ ~D :4 Ln Ln ~ Ln O ~ ~
n ~ ~ I .
~ ' + 1 ~ + l ~ ~ . ~ .
''~ JL~I .~ .
~n t~ Ln t~ tr) :4 Ln ~ o t~
t~~ t~ t~ tn ~ I O
+ ~ I L~
~ o,~
N o o ~1 o U~ o ~1 ~ ~ O
~ ~1 ~1 ~ ~h trJ o F; S-l I ....
Ln + l~ ~ +
o Ln ~~ Ln u~t;o t~ Ln o ~ ~ ~ ~ 4S~
. ~ ~ + 1- ~ ~ ~ o ~ rl I ~ ~
~' +1 o ~ ~.~
-~ o\ ~j~o * ~ O E~
, ~ ' ' ~ ~0
. ~
U~ ~
' ~X ~ o~ ' .~.
~ o
~ u~ X rd ~ rd m ~ ~ ~ U~ au
~ m ~ ,
rd ~ 4
4~ ~ 40 ,~; 40 ~ ~ U~
~ 4~ r~
' ~ O ,~ * lC lC
z; n) ~ .
. ~ 0 ~ ~\ r~
.~ ~ ~ o ,~ 5 ~ rd k
4r~ 1~ 4r~
_____ ___ _
-- 24 --
~oso366
Example 3
A thick and thin yarn, wherein the thick sections
of the individual filaments had a birefringence of 25 x 10 3
and the thin sections had a birefringence of 135 x 10 3
and the ratio of the diameter of the thickest sections to
that of the thinne-st sections was 1.45, was prepared by
non-uniformly drawing at a draw ratio of 1.55 a polyethylene
terephthalate undrawn yarn of 48 filaments having a
birefringence of 25 x 10 3. Then, the yarn was false
twisted.
- For comparison purposes, a polyethylene terephthalate
undrawn yarn as mentioned above was uniformly stretched at
a draw ratio of 1.9 and then false twisted.
The false-twisting conditions were as shown in
Table 2 below. The properties of the false twisted yarns
are also shown in the tableO The yarn according to the
invention (Run No. 8) was of desirable configuration in
that it contained many more portions having genuine twists
as compared with the yarn outside of the invention (Run
~0 ~o. 7).
.
- 25 -
~OS03G6
Table 2
Run No. 7 8
. De~ier . 144 1~6
Material Yarn
Draw.ing Uniformly Non-uniformly
- drawn drawn
. . _ .
Machine IFT-6 TFI-6
. Te~perature of heater (C)210 210
Conditions of Number of Twists (T~M) 2,500 2,420
False-twisting ~wisting Tension (g/filament) 12 25 -
Untwisting Tension ~ " ) 30 42
. Overfeed percentage (~) +2 -13
Twisting Direction S 5
Uster Persent Value 0.8 3.5
. . Shrinkage Ln Boiling
Water (%) 5.2 7.2
Properties of C.R. Value (%~ 41.2 40.9
False Twisted Tensil Strength (g/d) 4.0 3.2
Yarn Elongation (%) 24.0 34.0
Number of *2 .
Not-untwist Portions 5 300
Average Length of
. Not-untwisted Portions (mm) 5 . 13
wist Retention Coefficient 30 85
*1: Single heater type false-twisting machine having a heater
length of 1.2 m and provided with a spindle type twister,
manufactured by Toray Engineering Co., Ltd., Japan
*2: Number of not-untwisted portions per 100 m
. ~
3~ 03~;6
Example 4
A thick and thin yarn of 155 denier/48 filaments,
having birefringences of 39 x 10 3 in the thick sections
and of 123 x 10 3 in the thin sectiones prepared from a
highly oriented polyethylene terephthalate undrawn yarn,
was false twisted under th~ conditions of overfeed percentage
of -7%, twisting tension of 15 to 21 g, untwisting tension
- of 30 to 42 g, temperature of 210C and number of twists
of 2,420 T/M. The obtained yarn was doublea by imparting
S twists of 200 T/M. Then, using the doubled yarn as both
warp and weft, a 2/~ twill fabric of 62 ends per inch and
59 picks per inch was woven under a warp tension of 30 to
35 g and a weft tension of 20 to 25 g.O
A tropical fabric of ~5 ends per inch and 60 picks per
inch was also woven using a conventional false twisted
polyethylene terephthalate yarn of 75 aenier/24 filaments
as warp and the above-mentioned yarn as weft.
These fabrics were then scored at 75C for 20
minutes in water containing an anionic surfactant and soda
ash, and dyed using 3% o.w.f. (based on the weight of the
fabric) of Dianix Navy Blue ERF~ ~C.I. Disperse Blue 142)
at 100C for 30 minutes. The fabrics were then subjected
to reduction washing with caustic soda, hydrosulfite and a
nonionic surfactant. After drying, fabrics of desirable
sprinkly colored effects were obtained.
In thP dyed twill fabric, the rate of deeply dyed
portions was 44.7% and the lengths of deeply dyed portions
were in a range of l to 5 cm, and the average length was
2.3 cm; while in the dyed tropical fabric, deeply dyed
portions of the same lengths as above were observed only
* Trade Mark
- 27 -
A
lOSU3~6
in weft. The fabrics passessed a unique and faverable
feel and good fastness properties.
Example 5
A polyethylene terephthalate undrawn yarn, a
birefringence of which was 37 x 10 3, was drawn using a
hot pin of 35 mm ~ heated to 80C to obtain a thick and
thin yarn of 160 denier/30 filaments having an Uster
evenness value of 12% and birefringences of 37 x 10 3 in
the thick sections and of 105 x 10 3 in the thin sections.
The obtained thick and thin yarn was false twisted
under the following conditions. The temperature of the
first heater was 210C, the temperature of the second
heater was 200C, the relax rate was 15%, the ratio of
twisting tension to untwisting tension was 2.4 and the
number of tWlStS was 2,400 T/M. The Uster percent value
of the obtained yarn was 4.5 and the T index thereof was
13.
Using this yarn, an interlocking rib fabric was
knitted on a circular knitting machine of 20 gage. The
fabric was then relaxed at 90C for 20 minutes and dried
at 70C for 30 minutes. Then, the fabric was dyed on beam
dyeing equipment using 1.0% o.w.f. of Foron Rubine S-2GFL
(C.I. Disperse Red 167), 3% o.w.f. of Foron Red S-FL
(C.I. Disperse Red 72) and 1% o.w.f. of a nonionic disperslng
agent, at 130C for 60 minutes.
The fabric was dyed comparatively deeply in the
thick sections of the yarn-composing filaments and, thus,
possessed stripes of a sprinkly colored effect in the weft
direction. The rate of deeply dyed portions of this
fabric was 38% and the lengths of deeply dyed portions
- 28 -
~05~36~
were in a range of 0.5 to 3.0 cm, being 1.5 cm the average.
The fabric possessed a unique and favorable feel and good
fastness properties.
Example 6
A polyethylene terephthalate undrawn yarn, having a
birefringence of 40 x 10 3, was drawn at a draw ratio of
1.38 using a hot pin heated to 80C to obtain a thick and
thin yarn of 150 denier/48 filaments having a birefringence
of 41 x 10 3 in the thick sections and of 110 x 10 3 in
the thin sections.
The thick and thin yarn was then false twisted
under the following conditions. The overfeed percentage
was -6~, the ratio of twisting tension to untwisting
- tension was 0.51, the temperature of the heater was of
15 210C and the number of twists was 2,500 T/M. A false
twisted yarn having crimps of various wave lengths was
obtained. In the obtained yarn, the rate of crimps having
wave lengths not less than 1.5 mm observed under a tension
of 2 mg/d was 24~ and the number of crimps was 22 per inch
on the average.
Then, the yarn was doubled by imparting twists of
200 T/M and a 2/2 twill fabric of 60 ends per inch and 55
picks per inch was woven using the doubled yarn under a
warp tension of 35 g and a weft tension of 25 g. In the
fabric thus woven, many skip-dents in the form of slits
were observed.
The fabric was scored and relaxed at 75c for 20
minutes, heat set with hot air at 180C for 30 seconds
without extending the width, dyed at 100C for 60 minutes
30 and, then, heat set at 160C for 30 seconds with extention
- 29 -
3~i~
of the width to such an extent that the creases yielded
upon dyeing were removed.
The fabric thus processed had a very soft, smooth
feel touch and, thus, had a feel clearly different from
S those of fabrics produced from conventional false twisted
yarns. The birefringence of the fabric was 0.56 in the
warp direction and 0.64 in the weft direction, and the
ratio of the lower value of the friction coefficient to
the higher value of the friction coefficient was 0.87.
The spe¢ific volume was 2.55 cm3/g and the broken filament
counts of the warp and weft yarns were less than 10 per
2,000 m.
Example 7
A false twisted yarn, the same as obtained in
Example 6, was woven into a satin fabric and a plain
fabric under the same conditions as in Example 6. The
fabrics were then processed in the same manner as in
Example 6. The obtained fabrics had a softer and smoother
feel than those of fabrics produced from conventional
false twisted yarns. The friction coefficients of the
satin fabric and the plain fabric were 0.53 and 0.60,
respectivey, in the warp direction and 0.72 and 0.62,
respectively, in the weft direction, and the ratios of the
higher value of the friction coefficient to the lower
value friction coefficient were 1.36 and 1.03, respectively.
The speclfic volume was 3.2 cm3/g ln the satin fabric and
was 2.3 cm3/g in the plain fabric. In both fabrics, the
broken filament count of the fabric-composing yarn was
less than 10 per 2,000 m.
For comparison purposes, a uniformly drawn yarn of
- 30 -
~50366
150 denier/48 filaments, having a birefringence of 180 x 10 3,
was produced by drawing a polyethylene terephthalate
undrawn yarn having a birefringence of 5 x 10 3 at a draw
ratio of 3.5 using a hot pin heated to 100C. The drawn
yarn was then false twisted under the following conditions.
The overfeed percentage was +2%, the ratio of twisting
tension to untwisting tension was 0.57, the number of
twists was 2,500 T/M and the temperature of the heater was
210C. In this yarn, the percentage of crimps having wave
lengths of not less than 1.5 mm, observed under a tension
of 2 mg/d, was only 3% and the number of crimps was 19 per
inch on the average.
Then, the yarn was doubled in the same manner as in
Example 6 and the doubled yarn was woven into a 2/2 twill
fabric of 60 ends per inch and 55 picks per inch under a
warp tension of 35 g and a weft tension of 40 g. In the
fabric thus obtained, no skip-dents as in the fabric of
~xample 6 were observed.
The fabric was scored and relaxed at 100C for 20
minutes`a~d then processed in the same manner as in Example
6. The fabric thus processed had a hard and harsh feel.
The friction coefficient of this fabric was 1.4 in the
warp direction and 0.5 in the weft direction, and the
ratio of the higher value of the friction coefficient to
the lower value of friction coefficient was 2.8. The
specific volume was 2.4~ cm3/g.
- 31 -
