Note: Descriptions are shown in the official language in which they were submitted.
GEAR CRIMPED JASPE YARNS AND`PROCESSES
-
FOR THEIR M~NUFACTURE
The present invention relates to improved jaspe yarns
and to processes for their manufacture.
A j aspe yarn has the general appearance of two
differently coloured yarns twisted together; however, it is made
by texturing together two continuous filament yarns of different
dyeability and then dyeing the textured yarn, generally in fabric
form.
Gear crimping of synthetic yarns is well known in the
art. A process for drawing and gear crimping an undrawn
synthetic yarn is described in British Patent Specification
984,922. The use of undrawn polyamide and polyester yarns is
described. Gear crimping of drawn synthetic yarns is also known.
The use of undrawn polyester yarn in a draw-gear crimping process
is unsatisfactory because of extremely low bulk and breaking of
filaments in the process. The use of drawn polyester yarn in a
gear crimping process is unsatisfactory because of unacceptably
low bulk. The low bulk achieved is particularly apparent in
finished fabric made from the crimped yarn. ;
In our United States Patent No. 4,273,823, there is
described a drawn gear-crimped polyester yarn with latent bulk
the amount and nature of the bulk being such that the yarn has
an initial crimp as defined of at least 1.5%, preferably of above
2%, and a mechanical crimp stability as defined of above 0%.
The crimped polyester yarn may be produced by heating a drawable
polyester yarn having a birefringence in the range 32 x 10 3 to
125 x 10 3 inclusive, preferably 35 x 10 3 to 125 x 10 3 inclusive,
crimping the yarn by guiding it between the intermeshing teeth of
a set of toothed wheels such that the yarn is caused to follow a
sharply zig-zag path, the toothed wheels being rotated at a
sufficient speed such that the yarn is drawn by the tension so
imparted to the yarn by the toothed wheels and subsequently
forwarding the crimped yarn from the toothed wheels under a
controlled tension within the range 0.15 to 0.50 g per decitex
inclusive based on the
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decitex of the drawn polyester yarn.
It has now been found possible to produce a drawn
gear crimped jaspe yarn having a useful bulk. Compared with
conventional false twist crimped yarns, the bulk of the gear-
5 crimped y~rns according to the present invention is low;however~ the amount and nature of the bulk make the present
yarns extremely suitable for the production of fabrics having
desirable aesthetics.
According to the present invention, there is provided
a drawn gear-crimped yarn with latent bulk characterised in
that the yarn i~ a nod lly interlaced gear-crimped composite
yar~ comprising polyester continuous filaments and polyamide
continuous filaments in the weight ratio 90:10 to 10:90
inclusive, the gear-crimped composite yarn having an initial
15 crimp as defined herein of 2~o to 12%~ preferably ~% to 8yo~ a
mechanical crimp stability as defined herein of above 0~ and
having 40 to 140 interlaced nodes per metre.
Preferably the composite gear crimped yarn has been
nodally interlaced to an extent such that the yarn has 70
20 to 100 nodes per metre.
According to the present invention, there is further
provided a process for producing a drawn gear-crimped yarn with
latent bulk characterised in that a drawable polye~ter
continuous filament yarn having a birefringence of at least
25 30 x 10 3 and a drawable polyamide continuous filament yarn
having a birefringence of at least 30 x 10 3~are heated and
simultaneously drawn and gear crimped together as a composite
yarn by means of toothed draw rolls and the composite yarn
is forwarded from the toothed draw rolls under a oontrolled
30 tension within the range 0.15 to 0.50 g per decites inclusive
based on the decitex of the drawn composite yarn and is
subssquently interlaced to have 40 to 140 nodes per metre,
the weight ratio of the polyester yarn to the polyamide yarn
being in the range 90:10 to 10:90 inclusive.
Initial crimp (3K) and mechanical crimp stability
(KB) are defined as follows:-
:
763~7
~ he gear crimped composite yarn with latent
bulk is wound at a ten~ion of 1.0 centi-newton~ (c~) per tex
to form a skein of 1 metre circu~ference and total decitex
of 2500. Thus, for example, 16 wraps are required for a
yarn having a deoitex of 76. ~he skein is hung and preloaded
with a load of 0.01 cN per tex. ~he preloaded skein is
heated at 120C for 10 minutes to
develop the bulk and i9 then cooled. ~he skein is subjected
to a force of 1 c~ per tex for 10 seconds and it~ le~gth (~o)
10 i8 measured. After an interval of 10 min~tes, the length of
the skein iB remeasured (L1) supporting the pre-load of 0.01
c~ per tex. After an interval of 10 minutes, a force of 0.1
cN per tex is applied for 10 ~econds and ;mmediately afterwards
a high force of 10 c~ per tex is applied for 10 seconds. After
20 m~utes the length of the skein is measured (L3) under the pre-
load of 0.01 c~ per tex.
Tn;tial crimp (EE) = Lo~- L1 x 100Yo
Mechanical crimp stability (KB)=Lo - L~ x 100%
Tn~tial crimp and mechanical crimp stability values
used herein are the mean of EE and EB measurements respectively
on at least 5 skeins of yarn.
~he above procedure is similar to that described
in the German ~tandard DI~ 53840 and is conveniently carried
out on a Texturmat machine manufactured by Herbert Stein,
Munchengladbach W Germany.
Initial crimp (~E) i8 a measure of ths percentage
reduotion in length from the 3traightened length of a bulked
yarn as the result of the bulked structure. Meohanioal orimp
stability (KB) is a measure of the proportion of bulk remaining
after release of a speoified high load.
The yarns of the present invention possess a level
of bulk whioh is commercially aoceptable a~d the bulk is
sufficiently stable to tension. The advantages of ~uch yarns
are particularly apparent in fini~hed fabrics in which the bulk
-~ 7~ Y
has been developed.
~ he jaspe yarns of the present invention, when
made into fabrics and dyed such as to colour the polyester
and polyamide components differently, exhibit a~ attractive
speckled appe æ ance. In order to achieve this appearance,
it is important that the gear-crimped composite yarn has
been nodally interlaced such that the ya~ has 40 to 140 nodes
per metre. Composite yarns having less than 40 nodes per
metre produce dyed fabrics in which undesirable streaka
of each yarn component are seen.
~ he term yarn as used herein means a monofilament
yarn or a multifilament yarn.
~ he drawable polyester and polyamide feed yarns are
mado by melt spinning, the spinning condition3 being selected
guch that both yarns have a ~imilar re~idual draw ratio.
Preferably the decitex of the drawn composite yarn
is less than 150 decitex.
~ he term polyester as used herein means a polyester
or a copolyester and the term polyamide means a polyamide or a
copolyamide. ~he polyester and polyamide yarns may contain
additives such as antioxidants, stabilisers, antistatic agents,
delustrants or colouring materials.
~ he filament or filaments of the polye~ter yarn or
the polyamide yar~ may have a filament cro~-section which is
ciroular or non-circular for example trilobal.
~ he crimped composite yarn is forwarded from the
toothed draw rolls under a preferred tension in the range 0.20
to 0.40 ~ per decitex based on the decitex of the drawn compo~ite
yar~. ~orwarding the crimped composite yarn from the toothed
draw rolls under a low tension of less than 0.15 g per decitex
leads to problems of filamentation and yarn breaking and the
yar~ tends to lick back around the toothed wheels. The use of
a high tension of above 0.50 g per decitex produces a yarn having
poor mechanical prrperties and a bulk which appears to be due
predominently to edge crimping. Such bulk produced from edge
..
crimping does not yield useful bulk in fabrics made from the
yarns. mhe amount of buLk due to true ge æ crimping, measured
by EE, iB low and it~ ~tability i9 poor.
mhe drawable polyester and polyamide yarns may be
heated by contact with a heated plate or a heated circul æ
pin or by passage through a tube supplied with a haated fluid
such as hot air or superheated steam. ~he drawable y æn i8
preferably heated by contact with a heater at a temperature of
at least 150C.
m~he toothed draw rolls may comprise two or three gear
wheels one of which i8 driven and drives the other wheel or
wheels. Preferably the teeth are involute in shape. Preferably
the gear wheels have an integral step struoture as described
in British Patent Specification ~o 1 255 478. mension sufficient
to draw the y æn is exerted by pas~age of the yarn over the tips
of the intermeshing teeth of the rotating gear wheels.
~ n embodiment of the invention will now be described
by way of example with reference to the accompanying drawing
which is a diagrammatic representation of a process according
to the invention.
A drawable polyester multifilament y æn 1 having a
birefringence of at least 30 x 10 3 i8 withdrawn over one e~d
of cylinder 2 from a package 3 of wound y æ n. A drawable
polyamide mNltifilament y æ n 4 having a birefringence of at
25 lea~t 30 x 10 3 is withdrawn over one end of cylinder 5 from a
package 6 of wound yarn. Withdrawal is effected via pigtail
guides 21, 22 by rotation of feed roll 9 and nip roll 7, the
combined y æns being passed æound nip roll 7 a suffioient number
of times to avoid slippage o~ the yarn.
Downstream of the feed roll 9 and nip roll 7 there
are located intermeshiDg gear wheels 11, 12 a~d a yarn tensioDing
roll 13. ~he gear wheel 12 is driven by driving gear whee} 11.
single pa~sage of the composite yarn between the intermeshing
teeth of the ge æ wheels 11 and 12 induces orimp in the yarn by
causing it to follow a sharply zig-zag path. ~etween the feed
roll 9 and the ge æ wheels 11, 12 the yarn is passed once around
76~ ~
an electrically heated metal pin 19. ~he gear wheels 11, 12
are rotated at a sufficient speed compared to the feed roll
9 ~uch that the oomposite yarn i9 drawn by the tension exerted
on it. the location of the draw point being on the heated pin
19~
Yarn tensioning roll 13 i8 a stepped roll and
comprises roll 14 and roll 17 which is of smaller diameter than
roll 14. Rolls 14 and 17 have associated separator rolls 15
and 16 respectfully. The crimped drawn yarn iB withdrawn from
gear wheels, 11, 12 by tensioning roll 14 under a controlled
tension within the range 0.15 to 0.50 g per decitex based on the
decitex of the drawn composite yarn. The yarn is passed sufficient
times around tensioning roll 14 and separator roll 15 to avoid
slippage of the yarn. ~he tension in the yarn i9 then reduoed
by passing the yarn around separator roll 16 and roll 17.
Between roll 14 &nd roll 16 the composite yarn is nodally
interlaced by passing it through interlacing jet 18.
On leaving the roll 17, the yarn is wound on a ring
3pindle package 23 twist being inserted in the yarn below
balloon-guide 25 by rotation of the spindle and rotation of
a traveller (not shown) around ring 27.
The yarn 90 produced is 3 drawn composite yarn
having latent buIk. The b~lk may be developed by subjecting
the yarn in yarn or fabri¢ form, to a thermal treatment.
~he following examples illustrate but do not limit
the present invention.
EU~MPIE 1
A 95 deoitex 25 filament drawable poly(ethylene
terephthalate) yarn having a birefringence of 63 x 10 3 and
a 27 decitex 7 filament drawable poly(hexamethylene adipamide)
yarn having a birefringence of 46.6 x 10 3 were drawn and gear
crimped by a prooess as shown diagrammatically in the accompanying
drawing. ~he polye~ter filaments had a trilobal filament oross-
seotion and the polyamide filaments had a circular filament cross-
seotion. ~he weight ratio of the polyester filaments to the
s ~ ~ :
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polyamide filaments was 78:22. The heated metal pin was of
circular cross-6eotion having a diameter of 2.22 cm and a
temperature of 170C. ~he gear wheels were made of stainless
steel and had 38 teeth per inch. ~he intermeshing of the gear
5 wheels was such that the mAY;mllm overlap of teeth on the two
gears was o.356 mm.
~ he speed of the gear wheel6 was adjusted such that
the composite yarn was drawn by the tension imparted to the
yarn between the heated pin and the gear wheels. ~he surface
speed of the larger diameter ten6ioning roll was 840 metres per
minute and the ratio of the 6urface speed of the larger
diameter tensioning roll to the surface speed of the feed roll
wa9 1.30. The yPrn tension between the gear wheels and the
larger diameter tensioning roll wa~ controlled at 31 g, that
5 i9 at 0.32 g per decitex based on the decitex of the drau~
composite yar~.
The diameters of the two roll6 of the 6tepped tensioning
roll were such that the yarn was overfed from the larger diameter
roll to the smaller diameter roll at an overfeed of 3.1%. On
20 leaving the larger diameter tensioning roll, the overfed yPrn
wa6 nodally interlaoed by pa66ing it through an interlaoing
jet to which air was supplied at an air pressure of 60 pound6
per square inoh. ~he interlaoing jet had a yarn pas6ageway
in the form of a truncated cone and two directly opposed air
25 passageways for directing air into the yarn passaeeway at right
angles to the longitudinal acis of the y~rn. ~he trunoated cone
form of the yarn passageway caused the major portion of the
exhau~t air to pass out of the yar~ pa~sa~ew~y in the same
direction as the yarn.
~he oomposite yarn 90 produoed had a deoitex of 96
a~d posse~sed latent b~-lk. ~he yarn had 86 interlaced nodes per
metre (mean of 3 visual count measurements on 1 metre lengths
of the yarn). ~he yarn had an initial crimp, measured as
hereinbefore desoribed, of 3.4%, a meohanical crimp stability
35 of 27.0~, a breaking load of 347 centi-newtons and an extension
to break of 30.~.
~.
:, ~
~ he latent bulk yarn wae knitted into fabric which was
then dyed at 130C to colour the polyeeter and polyamide components
differently. ~ulk was fully developed in the knitted yarn
during the dyeing process. ~he fabric showed good bulk and an
5 attractive jaspe or speckled appearance.
EX~MælE 2
Example 1 was repeated except that the poly(hexamethylene
adipamide) feed yarn was a 42 decitex 10 filament yarn having a
birefringence of 45.5 x 10 3. ~he weight ratio of the polyester
filaments to the polyamide filaments wa~ therefore 69:31.
Similar process conditions as in Example 1 were used except that
the yarn tension between the gear wheel3 and the larger diameter
tensioning roll was controlled at 37.5 g, that i8 at 0.35 g
per decitex based on the decitex of the drawn composite yarn.
~he composite yarn 80 produced had a decitex
of 107 and passessed latent bulk. ~he yarn had 85 interlaced
nodes per metre (mean of 3 visu21 count measurements on 1 metre
length~ of the yarn). ~he yarn had an initial crimp of 3.4%~
a mechanical crimp stability of 32.8~o, a breaking load of 370
centi-newtons a~i an extension to break of 27.5%.
~ he latent bulk yarn was knitted into fabric which
was then dyed as in ~mple 1. ~ulk was fully developed in the
knitted yarn during the dyeing process. ~he fabric showed
good bulk and an attractive jaspe or speckled appearance.
25 EXAMPLE ~
Exa~ple 1 was repeated except that the poly(hexamethylene
adipamide) feed yarn was a 56 decitex 13 filament yarn having a
birefringence of 45.0 x 10 3. ~he wei~ht ratio of the polyester
filaments to the polyamide filaments was therefore 63:37.
30 Similar proces3 conditions as in F~mple 1 were used except that
the yarn tension between the gear wheels and the larger diameter
tensioning roll was controlled at 40 ~, that is9~ at 0.34 g per
decitex ba~ed on the decitex of the drawn compoeite yarn.
~he composite yarn 80 produced had a decitex of 118
35 and possessed latent bulk. ~he yarn had 85 interlaced nodes
per metre (mean of 3 visual count measurements on 1 metre lengths
.
~r7 ~ ~t'~ ,,
of the yarn). ~he yarn had an initial orimp of 3~7%~ a
me¢hanical crimp stability of 48.6%, a breaking load of 433
centi-newtons and an extension to break of 30.1%.
The latent bulk yarn was k~tted into fabric which
5 was then dyed a~ in Example 1. ~ulk was fully developed in
the kn;tted yarn during the dyeins pro¢ess. ~he fabric showed
good bulk and an attractive jaspe or speck1ed appearance.
EXAMæ$E 4
Example 1 was repeated except that the poly(hexa~ethylene
adipamide) feed yarn was a 96 decitex 20 filament yarn having a
birefringence of 46~o x 10 3. ~he weight ratio of the polyester
filaments to the polyamide filaments was therefore 50 50~
Similar process conditions as in Example 1 were used except
that the yarn tension between the gear wheels and the larger
5 diameter tensioning roll was controlled at 68g, that is, at
o~46 g per decitex based on the decitex of the drawn compoeite
yarn.
~ he composite yarn 80 produced had a decitex of 148
and possessed latent bulk. ~he yarn had 90 interlaced nodes
20 per metre (mean of 3 visual count measurements on 1 metre lengths
of the y~rn). ~he yarn had an initial crimp of 4.1%, a
meohanical crimp stability of 44.~, a breaking load of 523
centl-newtons and an extension to break of 27~6%~
~he latent bulk yarn was kn~tted into fabric which
25 was thsn dyed as in Example 1, Bulk was fully de~eloped
in the knitted yarn during the dyeing pro¢ess. ~he fabric showed
good bulk and an attraoti~e jaspe or speckled appearance.
COMP~A~IVE EXAMP$E A
Example 1 was repeated except that the following
30 conditions were used:-
Feed yarns 50 decitex 22 filament drawn
poly(ethylene terephthalate)
yarn.
40 decitex 10 filament drawn
poly(hexamethylene adipa~ide)
garn.
Pin temperature 160C
'
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3 ~
Surfaoe speed of larger
diameter tensioning roll 532 metre~ per minute
Ratio of te~ion roll ~urface
speed to feed roll ~urface
~peed 1.03
Yarn tension between gear
wheels and tensioning roll 20g
Overfeed to interlacing jet 1%
~he composite yarn ~o produced had only 31 node~ per
10 metre. Dyed fabric made from the yarn showed undesirablestreaks of each yarn component. Attempts to increa~e
the extent of nodal interlaoing by increa3ing the overfeed of
the yarn to the interlacing ~et led to difficulties in oontrolling
the threadline at interlacing and 3till produced a d~red fabric
15 with streaks of each yarn ¢omponent.
CO~lv~i E~ B
~mple 1 was repeated except that the following
conditions were used:-
Feed yarns 333 deoitex 30 filament drawable
poly(ethylene terephthalate)
yarn of birefringence 27 x 10 3
100 decitex 20 filament draw-
able poly(hexamethylene
~ipamide) yarn
Ratio of tension roll
surface speed to feed roll
surface speed 1.9
Yarn tension between
gear wheels and
ten~ioning roll 46g
Overfeed to interlacing
jet 1%
~he composite yarn 80 produced had a decitex of 217
and had only 22 nodes per metre. I)yed fabric made from the
35 yarn showed undesirable streaks of each yarn component.
. , , - : :
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~1.;1 ~7~i~ 7
11
Attempts to increase the extent of nodal interlacing by
increasing the overfeed of the yarn to the interlacin~ jet
still produced a dyed fabric with streaks of each yarn
component.
