Note: Descriptions are shown in the official language in which they were submitted.
WO 95116065 2 1 7 7 5 6 6 PcrluS94/1399S
MET}~OD A~D APPARAT~8 FOR IEEAT~ 7~ YARNg
AND rKvDUu O PREPARED ~ r~; ~
B~ ~KVUNL OF TIIE ~ ~V~C.~lUN
Field of thc Invention
The present invention relates to the treatment of
yarns which may be ~-ubse~u~a1.Lly used to manuracture
carpets and the like. More particularly, this invention
10 relates to a method of and ~alc.~ for heat-treating
ply-twisted, mult;fil I yarns in a continuoUs
operation, where the ply-twisted strands of yarn are
bulked and heat-set in their twisted, plied oondition.
15 Descril~tion of the R~l~ted Art
Yarn which is used as pile in carpets is typically
prepared by cabling or plying together two or more singles
yarns and heat-setting them in their plied condition. One
method involves heat-treating the yarn in a batch
20 condition as a skein Or yarn. Another method involves
treating the yarn in an array of loops on an extended
horizontal Cullvt:yu~ belt passing through a
steam-heated oven, such as a system ~m~f~ct~ed by
Superba. Another method involves treating the yarn as
25 hanging yarn loops advanced along by carrier belts on a
cantilevered horizontal mast through a hot air-heated
oven, such as a system manuf actured by Suessen . Such
methods require numerous --- on~ çol devices and a large
amount Or floor space in a yarn treating plant, and they
30 do not lend themselves to a compact continuous process for
unwinding, ply-twisting, bulking, heat-setting, and
winding of the yarn.
There is a need f or a s; _ l; f; P-i process and
apparatus rOr bulking and heat-setting ply-twisted yarn
35 that is compact and does not reguire a great amount of
floor space. Such a system should also be readily matched
in speed to upstream and downstream proce5sing ~
There is also a need for a process and apparatus that can
operate over a wide range o~ conditions to provide both
WO95116065 ~ 1 7 7 5 6 ~ PCTNS94113995
yarns suitable for making carpets having a highly textured
appearance, and, in other instances, yarns suitable for
making carpets having little or no teYture, d~rDn~;n~ upon
the desired carpet style. There is also a need for a
5 single device having the ~lexibility to only bulk the
yarns, or to bulk and ~ully heat-set the yarns, der~n~l i n~
- upon the operating conditions and desired product. There
ls also a need for a device that treats the yarn in a
uniformly relaxed state under no tension so that the yarn
l0 can freely shrink and bulk uniformly.
The present invention provides such a device and
methods for heat-treating yarns, along with the resultant
yarn L~L~ U~LS.
8m~ 7V OF ~ E lNVli~...l~N
This invention i n~ C a tubular heat-treating
apparatus comprising an elongated chamber having a yarn
entrance end and an opposed yarn exit end, and having a
fluid jet on the entrance end for introducing fluid into
the chamber. The chamber has an imperforate first portion
20 adjacent to the ~11LLc.l.c~ end for collecting a loosely
folded wad of yarn, a E~econd portion adjacent the exit end
for containing a loosely folded wad o~ yarn, and a
perforate third portlon int~ te the; _L~,L~Ite
portion and the cont~; ~ portion ror venting the fluid
25 from the chamber. The imperforate first portion comprises
at least 40~ o~ the length of the chamber. Preferably,
there is a fluid ~et on the exit end of the chamber for
i1,LL~,du. lng i~luid into the chamber. In another preferred
e~bodiment, there is a perforate portion adjacent to the
3 0 entrance end of the chamber for introducing additional
~luid into the chamber. In another ~ ., the
apparatus includes means to sense chamber ~ UL ~ at the
entrance end and means to vary the feeding of yarn to the
chamber based on the sensed ~Lt:~aUL~. A controller ~ay be
35 Used to vary the feeding in response to changes in the
sensed ~L;:~aUL~.
This invention also includes a method of heat-
treating a yarn comprising the steps of heating an
extended length of yarn with a heated fluid; forwarding
Wo 95~16065 2 1 7 75 ~ 6 Pcr/USs4/13s95
.
the extended yarn with a flow of the fluid into an
enclosed tubular chamber having imperforate and perforate
portions; collecting the yarn in loose Eolds within a
first im}7erforate portion of the chamber; passing the
5 fluid through the loosely folded yarn to heat-treat the -
yarn fi l ~ ; forwarding the loosely folded yarn through
the cha7lber by means of a force ;mhAl An~ e between the
heated fluid ~nd 7~riction acting on the loosely ~olded
yarn; venting the heated fluid from a perforate portion o~
the chamber int - ~te the ends o~ the loosely ~olded
yarn; cooling the loosely folded yarn in the chamber; and
pulling the cooled, loosely folded yarn into an extended
length to thereby unfold and extend the ~olded yarn. In a
preferred omhor7.; ' ~ the method involves cooling the
loosely folded yarn with a cool fluid passing through the
loosely folded yarn in a second imperforate portion of the
chamber. The cool fluid passe6 in a direction opposing
the heated fluid to cool the yarn. In another ~ --nt,
the method further includes heating the loosely folded
yarn with a second fluid, passing the second fluid through
the loosely folded yarn, and venting the second fluid
through the pe'Lrol.lte portions in~ ';Ate the ends of
the loosely folded yarn. The invention also includes a
nylon BCF product made by this process which has a
spec;75;c r-lec~ - mic:Lu;-L u~LuL~: as is evidenced by
specific shrinXage characteristics.
In one: ~ 7- , a ply-twisted yarn is only
bulked by passing the yarn through the above apparatus by
the above method and collecting only a short segment of
yarn under zero tension for a short time so that minimal
heat-setting occurs. The bulXed yarn may then be
suhsos!77O77tly heat-set by passing the yarn through a heat-
setting device.
7R7~r7~7~ D~ , OF ~777 F~ FIGm~Q
Figure 1 shows a section view of the heat-treating
device in a simple form.
Figure 2 shows a section view of an alternate
f '-:~; L of the heat-treating device.
WO 95/16065 2 1 7 7 5 ~ 6 PCT/US94/13995 ~!
Figure 3 shows 2m PYpl odPd view of a; et useful
with the device.
Figure 4 showæ a top view of four carpet samples
having various textures made with yarn ~ essed through
5 the heat-treating device under different conditions.
Figure 5 is a plot of shrinkage force versus
temperature for several yarn samples each treated
dif f erently .
DE'r~Ttrn l~ES~ OF THE LNvb~ N
Figure 1 shows a simple version of the heat-
treating device 10 of the invention. It consists of an
elongated tube 12 that define6 an elongated chamber 14
with tapered ends 16 and 18 to which is attached a hot
15 fluid jet 20. The device includes some means to feed
untreated yarn 4 0 to the device and remove treated yarn 41
from the device, such as nip roll pairs 24 and 26
respectively. Stationary guides, such as 15, 17, 2nd 19,
may be provided to add a slight tension to the yarn and
20 guide 21 may be added to provide a long span to permit
yarn vibration to exert a slight llntAn~l in~ force before
the yarn reaches nip rolls 26. These guides are
P~pee~Al ly usQful when multiple yarn ends are fed to the
device and the ends must be separated after being treated.
25 A hot fluid is fed to jet 20 through conduit 50 from a hot
fluid source 48. The flow of fluid from the hot fluid
source 48 to the chamber 14 may be controlled by a fixed
or variable flow control orifice 57. The tube 12 has a
first chamber portion 28 for c~ ec~ ~n~ a loosely folded
30 wad of yarn and heating it, a second chamber portion 30
for containing the wad of yarn and cooling it, and a third
chamber portion 34, between the first and second portions,
for containing the wad of yarn, venting the heating fluid
and stopping the heating . The f irst portion is an
35 ~ ~oL~te portion. The second portion i3 shown as an
roLe-te portion, but it may alternatively be a
perforate portion if it is desired to provide for flow of
a fluid transverse to the chamber and wad to aid in
W0 95116065 2 1 7 7 ~ 6 ~ PcrluS94113995
.
cooling the wad. The third portion is a perforate portion
to allow venting of fluids.
The chamber 14 is sized to ~. te a loosely
folded wad of the yarn being red in. As such, chamber 14
5 is preferably larger than twenty times the yarn ~ .r
and could be as much as 50 to 100 yarn ~i; ers in
average ~ gectional chamber .~ n, i . e . the
diameter of the chamber Cor a cylindrical chamber. It
should be large enough 80 that there are only a small
lO number of folds per inch in the yarn folded therein. The
first portion Or the chamber should comprise a Rj~nif~clnt
portion of the length of the chamber since it is in this
portion that the heating oi~ the yarn wad takes place by
forcing the heated fluid through the wad and maintaining
15 the heat for a particular r~-si~l~nre time. Preferably, the
fir6t portion of the chamber comprises at least about 40%
of the length of the chamber. The third portion, which is
a perforate portion, will be less than about 20~6 of the
chamber length. It is here that the fluid is rapidly
20 vented and heating to a yarn ~L~i L t _-~c.~u.~ is
stopped. The second portion of the chamber must be long
enough so the ne~-P~s~ry cooling takes place before tension
is applied to the yarn, and long enough to provide
5-1ff;. 1~ t space for unfolding of the yarn wad into an
25 extended length before the wad end 68 reaches the upper
tapered end 18. For instance, a length of at least about
one chamber diameter from the end of the wad to the
beginning of the upper tapered end may be desirable for
unfolding. The total length of the second portion depends
3 0 on the mode of cooling used .
Figure 2 shows another - '; r L of the heat-
treating device lO of the invention. It consists of an
elongated cylindrical tube 12 that defines an elongated
cylindrical chamber 14 with conical ends 16 and 18 to
35 which are attached a hot fluid jet 20 and cool fluid jet
22. The device in~ some means to feed yarn to the
hot ~ et and remove yarn from the cool j et, such as nip
roll pairs 24 and 26 respectively. Nip roll pair 24 is
driven by motor 25. It is contemplated that the speed of
W095/l606s 2 1 77566 PCT/US941139g5
the motor can be controlled by the operator or by
controller 27 receiving a control signal from sensor 67
that senses thc chamber pL-6DUL~ Pb. A cool rluid is ~ed
to jet 22 through conduit 62 ~rom a cool fluid source 60.
5 A ~irst hot i~luid is ~ed to jet 20 through conauit 50 ~rom
a hot fluid source 48. It i5 contemplated that the set
- point for the energy supplied to the hot fluid source 48
may be varied by the U~LatOL or by controller 27
receiving a control signal from sensor 71 that senses the
wad ~ aLuLe T4 through the wall of tube 12. The tube
12 has an imper~orate first portion 28 for collecting a
loosely ~olded wad of yarn and heating it, an imperforate
second portion 30 for cr-nt~n;n~ the wad of yarn and
cooling it, ~nd a peLruLate third portion 34 between the
~ir6t and second imperforate portions ~or containing the
wad o~ yarn, venting the heating ~luid and stopping the
heating. There is also a peLrurate ~ourth portion 32 that
provideD ~or i~low o~ a second hot ~luid into the chamber
14 through conduit 51 ~rom æource 48. Perforate third
portion 34 provides for flow of cool and hot fluids out o~
chamber 14. There may be a hood 35 surrounding tube 12
ad~acent perforate portion 34 ~or removing the ~luids that
flow out through p~LroL~te portion 34 to m;n1m;~e
~oncl~nc~tion o~ rluid vapors on tube 12 and reauce
convective heating of the second portion o~ the chamber by
rising heated fluids vented at the third portion. The
hood is in - ; r~tion with a vacuum source 37 via
conduit 39. There are provided means of controlling flow
of the cool and hot fluids, such as fixed or variable flow
control ori~ices 53, 55, ana 57 in cool fluid conduit 62,
hot fluid conduit 51, and hot fluid conduit 50,
respectively . There may be a chamber 3 6 within a tube 3 8
surrounding a portion of tube 12 (such as the ~irst and
fourth portions) which provides for heâting of the tube,
either by providing a space for insulation to prevent heat
loss, or by providing a space for circulation of a heated
~luid, such as the second fluid.
Figure 3 shows details of jet 20 which is useful in
the device of the invention for forwarding and heating the
WO 95/160G5 Z ~ ~ 7 ~ ~ ~ PCrNS94113995
yarn. The jet is operated at low jet pressure Pl tFlg 2)
of from about 1. 5 to 10 psig, so it will not supply a high
velocity stream of fluid that may disrupt the plurality of
filaments in the plied yarn being forwarded and heated.
5 The physical characteristics of jet 20 (and ~et 22) are
described further in U.S. Patent 3,525,134 to Coon. The
jet assembly 20 consists of a body 76 and a detachable
cover 78 having a hole 79 for passage of a bolt for
fastening the cover to body 76. Yarn line 40 moves
through passage 42. Conduits 44 and 46 supply ~ 8:,u~ ized
fluid to passage 42. The conduits are both the same
width, "do", and have a depth "dp" that is about 2 to 4
times the width "do" . The ~t ~stjuLized fluid is supplied
to the pair of conduits 44 and 46 from source 48 through
manifold 82 that includes ports 84 and 86. One of these
ports may be plugged during operation to reduce f low to
passage 42. The width "do" may be changed to also vary
the flow to passage 42. The flow rate of fluid from
source 48 may also be varied to change the flow to passage
42. The jet p~c~ are sized and the chamber ~s~uLa
Pb is set 80 that a slight blow-back through the entrance
end 43 of jet passage 42 occurs. This en~ures that no air
is aspirated into the ; et and into chamber 14 to dilute
the sllrP~-hP:!~ted steam therein.
Jet 22 in Fig 2 has a configuration similar to jet
20, and it is also operated at low ~)L-~S~U~e: P2 (Fig 2) of
about 1. 5 to 10 psig for unfolding and cooling the yarn
without disrupting the fll; Ls. Another ~et (not shown)
may also be positioned on top of and abutting jet 22 and
oriented in the same direction as jet 20. This additional
~et would be used to facilitate threadup of yarn line 40
through the device at st~lrtup ror each product; for
threadup, there would not be any loosely y-tl.ercd yarn in
the device and jet 22 would be turned off. An upwardly
angled hole (not shown) in the direction of yarn travel
may intersect conical end 16 and be sl~rP~ l ed with
~ _ ~ssed air to also aid in threading up the deviGe . A
wire could also be inserted through the j ets and chamber
14 and be attached to the yarn to pull it through for
W0 95/1606~ 7 7 ~ 6 ~ pCI/US94/13995 ~
threadup. The device of Figure 1 could also be threaded
up similarly.
The device of Fig 1 and Fig 2 may be used to
heat-treat different types of yarn including multiple
strand ply-twi6ted and single strand twisted yarns. The
tQrm "ply-twisted mul~ i f ~ l L yarr.", is meant to include
a yarn constructed by cabling together two or more singles
yarns in a unidirectional or alternate bi-direti~,n~
twist direction with the twist reversals between
alternations either bonded or l~hn~l~od Such yarns are
fi~r~ r to those skilled in the art. The device of this
invention may also be used to treat air-_~.Ldl~gled yarns
for di~ferent yarn styling effects. Preferably, the ply-
twisted yarn is r,.~rOc"~ of bulked continuous f ilament
lS (BCF) yarns, but staple spun yarns may also be used. The
BCF and staple yarn contain f ~ l Ls prepared from
synthetiC th. L l~ctic polymers 5uch as polyamides,
polyesters, polyolefins, and acrylonitriles. Polyamides,
such as poly - Lhylene a~ir~ o (nylon 6,6) and
polycaprolactam (nylon 6) are ~sror~l ly suitable.
In one ~ L, a ply-twisted, mUlt~ f ~ l L
yarn 4 0 enter~; the chamber 14 through j et passage 4 2 and
conical ~nd 16. A first heated fluid i5 directed at an
angle to passage 42 through slots 44 and 46 that are fed
by heated fluid source 48 through conduit 50 similar to
the jet device described in u.S. Patent 3,525,134 to Coon.
The heated fluid is preferably steam which is preferably
sl~r~rhr~ted by source 48, or the heated fluid may be air
heated by source 48. If air or saturated steam is used,
- 30 the rP~ciclon~ e times and t~ ~c L~LuL,s to achieve the same
heat-LL~:a~ L for a given product may be dieferent than
when ''"l' ~ I o~1 ed steam is used. The heated fluid forwards
the yarn through the conical end 16 and into the
cylindric~l chamber 14. The angle 52 made with the yarn
40 and the velocity of the fluid are such that the
f i l Ls in the yarn are not substantially disturbed or
entangled in the mul~ fi l -- t. bundle making up the yarn.
The yarn is forwarded and rapidly heated so that the yarn
regains any bulk that was previously imparted into the
WO95/16065 2 t 7~6 PcrrUs94/~399s
yarn. The forwarding velocity of the fluid must be low
relative to the yarn velocity, so the forwarding tension
on the yarn remains very low and essentially "ten~r nl ess"
bulking o~ the yarn can occur. The pressure Pb in the
5 chamber, resulting ~rom introduction of the hot fluid,
acts on the end 66 of the wad to propel the wad through
the chamber ~rom the first to the second portion.
Friction between the entire length of the wad and the
walls of the chamber resists the propulsive force of the
10 pL~s~uL~, The speed of the yarn entering the device is
det~nm~n~d by the speed of rolls 24, and the speed of the
yarn exiting the device is det~-rm; n~d by the speed of
rolls 26. Since some shrinkage is common during heat-
treatment of many yarns, the speed of rolls 24 may be 15-
20~ higher than rolls 26. Rolls 24 and 26 are ~Yr~rli~rry
of means to feed and remove yarn to and from the device,
but additional pro~ e~:s1n~ e~r~i~ L u~LL_~u and
dc~ L~ t a~u of the device could alternatively provide these
means. For instance, a two-~or-one twister made by the
2 o Volkmann Company could provide means to remove the yarn
when the heat-treating device is inserted ahead of the
winder on the twister.
Rererring to Fig 2, it has also been round
advantageous to provide a second supply o~ hot rluid for
25 heating and propr~l 1 ing the wad Or yarn by adding another
flow of hot fluid ~rom source 48 via conduit 51 through
tube 38 to chamber 36 and then through perforate fourth
portion 32 to chamber 14. This permits the addition of a
large flow of hot fluid for heating the wad of yarn
3 o without having a high velocity stream . Ir the additional
flow had to go through the ~et 20, it would increase the
~low velocity and detri~ 1 ly entangle and tension the
yarn f ~1 i ~ . To ~urther ensure the flow o~ additional
hot fluid does not entangle the yarn as it is deposited in
35 loose folds, the pelL~Lte fourth portion may be
positioned away from the yarn entrance end of the chamber;
and may be positioned just beyond the end 66 of the wad
where the fluid would still pass through most of the
length Yl of the wad that is heat treated in the first
~ 1 7~5~
Wo 9S/16065 PCr/US94/1399S
I~ortion 28. The propulsion pressure would have to be
maintained on the end of the wad. With this variation in
the position of the fourth portion, the length of the
imper~orate first portion of the chamber would be the sum
5 of portions upstream and downstream of the perforate
~ourth portion. Jet 20 could be rp~pci~nl~d to provide a
high steam flow at a low velocity, but it would be
inconvenient to have to redesign and fabricate a new jet
20 for every new yarn or operating condition desired. It
10 is therefore preferred to design jet 20 for ~orwarding and
rapidly heating the yarn, and providing a sQcond supply of
low velocity fluid ~or bulk heating of the yarn to a
uni~orm temperature. If a high flow of hot fluid i8 not
required, the second fluid is not needed and the perforate
15 fourth portion in Fig 2 can be eliminated.
The yarn 40 is col 1 ected in the chamber 14 in loose
folds ln imperforate portion 28. A given piece of yarn in
the wad may remain in imperforate first portion 28 for a
significant time period due to the slow advance of the wad
20 ana the length of imperforate first portion 28. The
loosely folded yarn is heated by passing the heated first
zmd second fluids through the loose folds to thereby heat
set the ply-twist into the yarn. The loosely ~olded yarn
i8 then cooled in imperforate second portion 30 to "lock
25 in" the ply-twist before the yarn is pulled ~rom the
chamber .
In the case of Fig 1, the yarn is cooled by
stopping the heating by venting the heated fluid at
perforate third portion 34 and by making the length of
3 0 portion 30 long enough such that the yarn wad cools by
contact with the walls of the elongated tube 12. The
walls are exposed to ambient temperature conditions or
this portlon of tube 12 may be perforate to expose the wad
to a cool ~luid or a moving ambient fluid that increases
35 the heat transfer from tube 12.
In the case of Fig 2, the yarn is cooled by
stopping the heating and passing a cool fluid through the
yarn wad. The heating is stopped by venting the heated
~luid at peLrc~Lc-t.e portion 34. The cool fluid enters
2~ 77566
Wo 95116065 PCTIUS94/13995
chamber 14 through jet 22 and conical end 18 and passes
through the loosely folded yarn in ~ ro,a~e portion 30.
The hot and cooler fluids meet in opposing flows and are
vented from the loosely rolded yarn and the chamber in
5 perforate portion 34. The loosely folded yarn is unfolded
into an eYtended length and passes through conical end 18
and passage 54 of cool jet 22, pulled by rolls 26. A
cooler fluid is directed at an angle to passage 54 through
conduits 56 and 58 that are fed by cooler fluid source 60
10 through conduit 62 as in the jet device described in U.S.
Patent 3,525,134 to Coon. The cooler fluid flow opposes
the forward motion of the yarn through the imper~orate
portion 30, conic21 end 16, and passage 54. This acts to
unfold the yarn as it is pulled from the ch2mber 14 by the
rolls 26. The angle 64 made with the yarn 40 and the
velocity of the fluid are such that the ~ in the
yarn are not substantially disturbed or entangled in the
multi ~ bundle. The cooler fluid flow passing
through the wad rapidly cools the wad, the fluid pressure
20 reduces the requirement for a fricticnal length o~ wad to
oppose the wad prop~ n by the hot rluid pressure and
thereby stabillze the motion of the wad, and the cool
fluid flow effectively unrolds the wad in a short space.
As a result, the length o~ the second portion of the
25 chamber can be m~n~m~79~1 by this cooling mode, thereby
contributing to a compact assembly.
Referring to Fig 2, the flow Or the heated fluids
through the loosely folded yarn in 1 -- rvLate portion 28
produces a prQpUl ~inrl ~resDuLe Pb on the end 66 of the
3 o loosely ~olded yarn. The rlow of the cooler fluid through
the loosely folded yarn ~L.duces a retarding ~Lc6~uLe Pt
on the end 68 of the loosely folded yarn in ~ roLate
portion 30. Pb may be measured by sensor 67 that monitors
the pLCD~ULC in chamber 14 adjacent the hot jet 20, and Pt
35 may be ~ d by sensor 69 that monitors the ~rcS~ULc in
chamber 14 adjacent the cool jet 22. The ~ C~ULc Pv on
the wad in perforate portion 34 is essentially atmospheric
(Pv = 0 psig), since the fluids are vented in this
portion. The fluid ~r'c~ .ULcS Pb and Pt in the chamber
WO 95/16065 2 t ~ ~ 5 6 6 PCT/US94113995 ~
that act on the ends 66 and 68 of the wad 74 should be
maintained at z low level, preferably less than 5 psig, so
the wad is not compacted, resulting in sharp bends and
kinks in the yarn. The loosely folded yarn sliding on the
5 inside surface oi~ the tube 12 produces a retarding force
in the direction of arrow 70 proportional to the wall
shear stress ~actor Tw, l ~ ~3~ ing the resistance of the
fluid6 and yarn wad flowing in the tube 12. This reflects
the dynamic ~riction of the yarn in the tube which depends
lO on the surface finish inside tube 12 and the finish on the
yarn. An ;~hAlAn-e between the propulsion pressure, wall
friction, and retarding yLeS~-ULC: results in forward motion
of the loosely ~o~ ded yarn through the chamber 14 in the
direction of arrow 72. As the loQsely folded yarn wad
15 moves, yarn is added to the wad by yarn entering through
jet 20 and yarn is removed from the wad by yarn being
pulled away through; et 22 . The result is that the ends
66 and 68 o~ t~e moving loosely ~olded yarn wad remain at
the same relative positions in chamber l~, and the length
2 o of the loosely folded section of yarn 74, shown in Fig 2
as a low density wad, remains a nearly constant length Yt.
In order to maintain the device operation in a
stable state, the sensor 67, that senses chamber pressure
Pb acting on the bottom of the wad, may be monitored by
25 the operator and the speed of nip roll motor 25 may be
varied based on changes in the sensed pressure. It has
been found that the plesDuL~ Pb is a good indicator of the
length of the wa-d portion Yl for a given yarn. If Yl is
kept constant, the pLesDuLe Pb remains constant and the
30 residence time for heat-LL-~a, L of the yarn in portion
Yl remains constant. This results in a stable operating
condition that produces uniformly heat-treated yarn. If
Pb were to increase, it would indicate that the wad length
increased (and rp~:idpnt e time increased), so the rolls
35 would be slowed to deposit less yarn in the chamber. If
Pb were to decrease, it would indicate that the wad length
decreased (and residence time decreased), so the rolls
would be sped up to deposit more yarn in the chamber. It
may be useful to automate the control of the nip roll
12
Wo 95/16065 1 ~ 5 ~ ~ Pc~rluS94113995
speed by sending the output of the sensor 67 to controller
27 which can automatically vary the speed Or nip roll
motor 25 in response to changes in the sensed chamber
pressure Pb to maintain a preselected level of p~ ULe.
Rererring to Fig l, there is no pLeDDuLe Pt acting
on the wad or yarn, so a s~f~ci~rt length or yarn wad is
present in i-~yeLruLLLte second portion 30 to provide enough
dynamic friction of the yarn in the tube to oppose the
propulsion ~LaS-~ULe. A slight; -1 Anre as yarn i5 added
and removed from the wad results in forward motion of the
loosely rolded yarn through the chamber 14 in the
direction of arrow 72. As the loosely folded yarn wad
moves, yarn is added to the wad by yarn entering through
jet 20 and is removed rrOm the wad as yarn is pulled away
through conical end 18. The result is that the ends 66
and 68 of the moving loosely rolded yarn wad remain at the
same relative positions in chamber 14, and the length of
the loosely folded section of yarn 74 remains a nearly
CUI~ GI~L length Yt.
2 0 Rererring to Fig 2, in operating the device, the
residence time of the length Yt Or wad 74 is rl~t~rm; nPd
for the desired heat-setting. Typically, times Or 90 or
120 seconds are used with the tl1luuy11~uL Or about 50 YPM
set by a yarn twister U~JD LL e:alU of the device . The
tl1Luuy1~uL of the twister varies dep~n~9;n~ on the number
of twis~s per inch put into the plied yarn. The hlgher
twists per inch lower t_e yarn throughput and the yarn
p~cks less densely in the chamber, resulting in a lower
density wad. The r~ci~nre time aan be es~Ahl; Ch~d by
csnc~ ring the wad density, the rlOw of hot fluid through
the wad, the l,JLC~aULe Pb Or the first and second fluids on
the wad, and the ~L~=SDULe Pt Or the cooler fluid on the
wad. The ~eed speed and take away speed need to be
selected and proportioned to the shrinkage Or the yarn.
The rirSt and second rluids are preferably steam that is
prererably s~r~rh~Ated, and the cooIer fluid is preferably
ezsDed air that may be heated to a temperature below
the heat-set t~éLaLuLe o~ the yarn and the temperature
of the hot ~luids. The initial wad length is det~rm;n~d by
13
wo 9S/16065 2 l 7 7 5 ~ 6 PCTIUS94/1399S
the delay in taking away the yarn when the process is
started up. The wad density and - v, L is also
det~ n~9 by the opposing steam and air flows and the
wall friction for a given yarn and twist level. The steam
may typically be moving at about 16 ft/sec through the wad
while the wad moves at about . 02 ft/sec. The method and
apparatus are also compatible with higher speed twisters,
such as an alternate twist ply machine using jets to twist
the yarn at speeds of about 300 YPN. To achicve the same
residence times at higher speeds, the chamber can be made
longer or larger in ~;L~,ss-section i~ n~ A~y to
~c~ te more yarn.
The forces of the fluids flowing through the wad
and the wall shear keep the wad in position as yarn is
added and removed from the moving wad . Relatinn~h ~ rs that
govern the steady state length of the moving wad during
operation of the device are as follows.
The pLeS~UL ~ drop through the wad portion Y1 in
imperforate first portion 28 is S:
S -- (uhvh/k) (~Le~uLa drop/length of wad)
where uh is the viscosity of the hot fluid, vh is
the mean velocity o~ the hot fluid through the wad based
on the ~Las~>uL~ drop through wad portion Y1, and k is a
factor related to the permeability of the wad, taken from
Darcy's Law ~or ~Le~i~ULe and flow.
me pLes~uLa drop through the wad portion Y3 in
imperforate second portion 30 is A:
A = (UCvc/k) (~L~=6~Lt: drop/length of wad)
where UC is the viscosity o~ the cool fluid, and VC
is the mean velocity of the cool fluid through the wad
based on the ~reD~uLe drop through wad portion Y3.
me friction of wad portion Yt along the chamber
wall is F
F - 4Tw/D (shear stress/length o~ wad)
~5 where TW is the shear stress ~actor and D is the
diameter of the chamber.
The total wad length is Yt
Yt = Yl + Y2 + Y3
14
~ WO 95/16065 2 1 7 7 ~ ~ 6 PCTIUS94/~3995
and for steady state conaitions:
YlS - Y3A 5 YtF (for Fig 2)
Data was col 1 ectD~ for 24 test6 at stable operating
conditions covering seven different nylon 6, 6 BCF yarns
and two different heat-setting conditions producing
various te ~LuLad looks using the device of Fig. 2. The
following representative data are averages ror these
tests:
Pb minus Pt = 15.44 inches of water ~ras~uLè
S ~ 4 . 74 (delta P in inches of water press . per
inch of wad)
A - 2 . 42 (delta P in inches Or water press. per
inch of wad)
F ~ l. 56 (stre~s in inches o~ water press .
per inch Or wad)
Yl = 4 . 3 2 inches
Y2 ~ 2 . 0 inches
2 0 Y3 = 2 . 6 6 inches
Ytotal -- 8 . 98 inches
D = l . 3 l inches
Tw ~ 0 . 513 inches of water (dcrived from earlier
experimental work)
Pl - 2 . 5 psig
P2 - lO. 0 psig
Pv ~ 0 psig (ambient)
Pb = 24 . 5 inches o~ water pressure
In operating the device Or Fig l, it has been found
that the cooling o~ the yarn does not always reS~uire
forcing cool rluid through the wad of yarn. In some
cases, the yarn may be cooled s~ff~ri~tly by passing the
yarn through the unheated second portion 30 of the chamber
14 beyond the peLr-,Lal,e third portion 34 where the heated
rluid is vented. When this second portion is long enough,
the wad will spend enough ti~e in this second portion 80
the yarn will cool below the heat-treatment tL.~.~éLaLuLa.
This second portion may be i. ~eLruLa-e as shown in Fig l,
wo 95/16065 2 1 7 7 5 ~ 6 PCTiU~94/13995
or it may be pelr.,Lc.te to 2110w passage of a cooling
fluid, for instance in a direction ~ Vt:L~.e to the wad
74 and chamber 14, to speed up the cooling. When the
total wad length Yt is long enough, the friction o~ the
5 wad in the chamber will be sl1ff~ nt to balzmce the
~Le:S::iUL~ Pb acting to propel the yarll wad. With this
controlled propulsion, a constant, steady state, length of
yarn wad result6. In this situation, the above-aescribed
steady state formula becomes:
YlS 2 YtF,
since there i8 no oppos~nq p~s--u~e: acting on wad lQngth
Y3 .
In this case, the end of the wad 68 may be located
adjacent the conical end 18, but preferably the wad does
15 not contact the end 18. The small diameter of the conical
end helps stop any clumps of yarn from exiting the chamber
and entering nip rolls 26. Alternatively, the length of
the second portion of the chamber 14 may be shortened, the
angle of the cone may be reduced to about 10-20 degrees
20 included angle, and the wad allowed to contact the
tapering walls of the conical end 18. This contact with
the tapering walls provides a gentle resistance to
yLt:S~ULe: Pb without creating problems of wad clumping and
j amming that may occur with a stéeper cone angle . The
25 longer length o~ the ~h~ L angle cone end also
provides more space for unfolding than the steeper angle
cone. Three means have been tl~cl~sec~ for resisting Pb to
stabilize wad - ~ L: l~ providing a long chamber length
to develop s~ff~ci~nt frictional resistance with a long
3 0 wad length; 2 ) providing 2 shallow angle cone end to
retard wad - ~ L without clumping and jamming: and 3)
providing a retarding plessuL~ Pt on the end of the wad
that may also serve to rapidly cool the wad. The third
means is preferred to provide the most compact and easily
35 controlled arrangement for the device.
The device of this invention can be operated over a
variety of conditions to produce a variety of results.
For instance, the device can be operated as described
above, where an elongated portion of loosely gathered yarn
16
Wo 95/16065 2 t 7 ~ ~ 6 ~ PCT~'S94/13ss5
is allowed to accumulate in the chamber 2nd dwell there
for an ~ ~t~n~'Qd time to produce a yarn that is bulked and
fully heat-set. In another case, le6s yarn can be
accumulated for a shorter time so that _ lete heat-
setting does not occur. In still another case, only a
small portion of yarn is; cc~ A~ted ~or only a few
- seconds so that no appreciable heat-setting occurs, but
the yarn product is still fully bulked in the device under
no tension. Operation of the device in order to only bulk
the yarn may be useful if it is desired to s~hsecluPntly
heat-set the yarn in a subsequent step, such as with the
Suessen device referred to above. It is believed that one
problem with the Suessen device is that it cannot remove
tension effects caused by gravity and friction acting on
the yarn loops hun~ on its forwarding ~- Ani~, so non-
uni~ormities in bulk may result. Thus, separately bulking
the yarn under zero tension before subsequent heat-setting
has been found to be ~ ~-n~ ciA7 .
Tests have shown that nylon BCF yarn which was
first bulked in the device of this invention and then
passed through the Suessen device had better bulk
uniformity than nylon BCF yarn which was both bulked and
heat-set in the Suessen device. This ~ d uniformity
was evident when the nylon BCF yarns were made into cut
pile saxony carpet samples. A repetitive pattern called
"chevrons" was a}~sent in the carpet sample having yarns
which were separately bulked in accordance with this
invention. However, these chevrons were present in the
carpet sample having yarns bulked on the Suessen.
As previously mentioned, the device has a high
degree of flexibility in operation to produce a variety of
products. In turn, these yarns may be used to prepare
carpets having various t~:,.LuL~:s . It is also re~o~n ~ 7~C7.
that varying t~e twist level in the yarn and the
composition of the synthetic 1'-1~ t,. of the yarn produce
further product variations.
In general, the device has been found to operate
well and make useful nylon 6, 6 BCF yarn products when
operated over a range of t~ CLLULe:S from about 160 to
17
W0 95/16065 2 1 ~ 7 5 6 $ PCTIU594/13995 ~
210C, A yllrn entrance speed o~ about 50 yds/min, And ~
range o~ heat-treatment r~ci~ nre times from ~Ibout 60 to
180 seconds during which time the yarn is between the
el1~La11ce and exit of the device (essentially always in the
5 loosely folded condition). It is believed the device
would also operate well at speeds up to about 500 YE~. It
is believed important to good heat-treatment that the yarn
be held at a t~l~LaLure below its melt polnt for an
extended period of time to insure all ~1 in the
10 yarn bundle reach the same tc~ La~uLc:; this results ln
highly unlform heat-treating of the yarn. Carpets
composed of nylon yarn samples made outslde the lower end
of the ranges stated above showed poorer texture
retention, tuft deflnition, and texture.
It i6 also recoqn~ 7"~ that a plurality of ply-
twisted ends may be passed through the devioe
simultAneo~1c1 y without p~ n~ntly ent~nq1; nq the yarn
Qnds. The mass flow rates and passage diameters would
have to be adjusted to A~ te the greater total
20 denier of yarn. In order to aid in separation of the
plied yarn ends after exiting the elongated tube 12 and
before r~A~h1n~ the means to remove the yarn, the combined
yarn ends can be passed through a known tensioning device,
such as a ladder type t C~ncion~ and passed over a long
25 ~n~ l ~ ,L ~ed span under tension as shown in Fig. l . The
individual plied yarn ends could then be separately wound
on bobbins for furtber proc~ ing. Such a winder can be
the means for removing the yarn. Six ends of yarn were
~Lvcessed through the device of Fig l with the addition of
30 a second heated fluid through a perforate fourth portion,
such a6 portion 32 in Fig 2.
Although the device has been described as belng
oriented vertically with the yarn entering the lower end
o~ the device, it is believed that the device orientation
3 5 is not critical and the device could be oriented
horizontally or at an angle to horizontal, or the device
could be operat~d with the yarn entering the upper end.
various known methods for initiating ~ormation of the wad
18
~ WO95/16065 2 1 77~ PCr/Uss4113995
can be used and the means to ~eed yarn and remove yarn
controlled to then position the wad ends in the chamber.
The present invention is further illustrated in the
following Examples, but these r ~ lPC should not be
5 concidPrpd as limiting the scope o~ the invention.
T~8TING MET~OD8
The following Testing Methods were used to measure
various yarn and carpet sample properties, as further
l0 described in the below r lPq.
C~rP~t W~r
Wear tests which closely correlate to floor
tra~ficking were conducted in a Vetterman drum test
15 apparatus, Type RSG manu~actured by S~-hoPnhPry ~ Co.
(Baumber, Fed. Rep. o~ Germany). As spP~if;ed, the drum
is lined with carpet samples into which i5 placed a 16
pound steel ball having ~ourteen tl4) rubber buffers which
rolls randomly inside the rotating drum. A circular brush
2 o within the drum is in light contact with the carpet
surface and picks up loose pile i~ibers which are
cont;nl10ucly removed by suction. After 5,000 cycles, the
samples are removed and inspected to evaluate texture
retention. Texture retention or "newness retention" is
25 reported on a scale of 1-5 with a rating o~ 5
corrPspnn~l;n~ to an untested control s2mple, 4
corresponding to a lightly worn sample, 3 to a moderately
worn sample. A rating of 2 ~ OLLe:~ull~S to unacceptable
wear, and l corresponds to an c:x~ ~ -1 y matted sample.
C~rl~et Bulk
Carpet bulk was measured as the __~sYed pile
height in inches of a carpet sample that is loaded with a
~L_S~uLe: 0~ 1 lb./in2 (703 kg/m2). The carpet sample is
35 placed on a platform which is attached to a vibrator. The
sample is vibrated lightly for 5 seconds prior to
measuring the pile height using a thickness gauge which is
also attached to the vibrating platform. The vibration
allows the foot o~ the th;c~nPCc gauge to settle into the
19
WO95/16065 2 l 7~6 PCr/US94/13995 ~
surface of the carpet. Carpets with high bulk values have
high readings of REU.
8hri~-kA~ Forco
The shrinkage force o~ the yarn samples was
measured on a thermal analyzer made by the Kanebo Company.
A closed loop of sample yarn W7S placed between two spaced
pins in an oven. All of the slack was removed from the
loop and a load cell was attached to one o~ the pins to
record shrinkage forces in grams as the sample was slowly
heated in an oven over a period of time. A plot of
temperature and tension is recorded for each sample as it
shrinks .
EXa~Pl,Es
A ply-twisted yarn, comprising a pair of nylon 6,6
bulked continuous filament (BCF) yarns, Type ~150-696AS,
available from the DuPont Company, having a denier of 1150
each, and ply-twisted at a twist level of 3.75 turns per
inch, was processed through the device of Fig 2 controlled
by the operator at a variety Or operating conditions. The
treated ply-twisted yarns were tufted into a backing
material to form cut-pile carpet samples each having a
weight o~ 32 oz/yd2 and 2 pile height of 5/8 inches. As
illustrated in Fig 4, four cut pile carpet samples were
compared in a side-by-side comparison under the same
viewing light conditions and given the following ratings:
C-l9 - a low to no t~ uL-~d appearance;
C-24 - a low textured appearance;
C-35 - a medium textured appearance; and
C-39 - a high textured appearance providing a
highly variegated effect.
The following Table I summarizes the different
operating conditions to produce the yarns for the four
above-described carpet samples using a cylindrical chamber
of about 1.31" ~ r and about 37" long, where the
imperforate first portion was about 21" long, or about 57%
of the length of the chamber. The perforate third portion
of the chamber was about 2 " long or about 5% of the length
21 775~6
Wo 95/16065 PCT/US94/13995
of the chamber and the perforate ~ourth portion was about
3 " long .
TABLE I
S
C-l9 C-2 4 C-3 5 C--3 9
~ .
T~ ~LUL~ T4, (C) 188.6 196.3 200.3 204.0
lO Yarn Res . Time, 92 . 6 119 . 5 95 . 5 123 . 5
(seconds ~or Yt)
P1 ( ~- LL llnce j et press 2 . 5 2 . 5 2 . 5 2 . 5
in psig)
do (entrance jet size 40 (1) 40 (1) 80 (1) 80 (2)
in mils)
P2 (exit jet press 10 10 10 10
2 0 in psig)
(l) only one steam port on entrance jet
(2 ) two opposed steam ports on entrance j et
25 Com~r~tive ~3~m~1e~
In comparative tests, untreated Type 1150-696AS BCF
nylon yarns, as described above, were passed through a
Suessen heat-setting device under a ,~ 'e~ setting
~or the sample yarn of about 40 seconds r~ci~l~nce time at
30 195C hot air temperature under ambient ~LaS~ULe:. In
another instance, the untreated Type 1150-696AS BCF nylon
yarns were passed through a Superba heat-setting device at
a ~ 7 setting for the sample yarn o~ about 40
- seconds residence time at 132C steam t~.~.~eLllLULt: under
35 about 15 psig ~ s,,u,e. The yarns were respectively
tufted into backing materials to ~orm two ai~ferent cut-
pile carpet samples each having a weight of 32 oz/sq.yd.
and a pile height of 5/8 inohes. The carpet samples had a
e~ pearance
WO95/16065 21 77~G PCT/US94/13995 ~
The following Table II provides some peL rVLlUanCe
data for the above-descrlbed carpet samples.
RT.~ II
(Suessen) (Superba)
C-l9 C-24 C-35 C-39 Control Control
lO Texture 2.9 2.7 2.7 2.2 3.1 2.5
Retention
Reu Bulk 0.499 0.478 0.439 0.464 0.472 0.461
( l lb )
As shown in the above Tables, Sample C-l9, having a
low to no textured appearance, contained yarns processed
through the device of Fig 2 with the minimum steam ~low
rate through the forwarding; et that would still tension
the U~DLL~alU yarn enough to reliably strip the yarn off
the feed rolls. This rlow rate was achieved using a
single 40 mil jet conduit. The texturing effect of the
device seemF: to be most 3ensitive to the steam flow rate
through the forwarding jet; a higher flow rate of steam
spreads the plied yarn apart and bends it more sharply as
it is folded in the chamber.
Sample C-24, having a low textured appearance, was
slightly more textured than C-l9, and this was obtained by
increasing the t~ _ atULe: and time that the loosely
folded yarn was exposed to the steam in the chamber.
Sample C-35, having a medium textured appearance,
was made by increasing the flow rate by using a larger
conduit in the jet: the effect of the temperature and time
changes with this sample were considered insignificant.
Sample C-39, having a highly textured appearance,
was made by further increases in the flow rate by
providing another conduit in the jet; the effect of the
temperature and time changes for this sample were
cnn~ red insignificant.
4 0 The yarn samples made in the device of this
invention that were tufted into carpet did not show any
characteristics of poor bulk uniformity, such as
22
W0 95/16065 2 1 7 7 ~ ~ ~ PCT/US94/13995
"chevrons", in the tufted cut pile carpets. The yarn
samples made in the device o~ this invention that were
al60 tu~ted into carpet samples had better stain
resistance (characterized by a slow dyeing rate) when
5 compared with the comparative yarn samples heat-treated in
the Superba device. The dyeing rate o~ the yarn samples
- made in the device of thi6 invention was similar to the
dyeing rate of the comparative yarns heat-treated in the
Sues~en device.
Another yarn characteristic indicative of molecular
micro-,,L,~ LuLc WaS measured, the Kanebo chr;nk~e~ to
distinguish the above-described inventive yarn samples
from the comparative yarn samples.
A characteristic plot o~ temperature and tension is
recorded for each yarn sample as it shrinks. Fig 5 shows
a plot Or a single yarn type treated with the device o~
the invention under two different operating conditions
compared to treating in the Suessen and Superba devices
and to no treating. Samples C-24 and C-l9, which typi~y
products o~ the invention, are shown as curves 88 and 89
respectively. The control l sample treated on the Suessen
device is shown as curve 90, and the control 2 sample
treated on the Superba device is shown as curvc 92. The
non-heat-treated sample is shown as curve 94.
It is believed that the shape and position of the
shrinkage data curves of the yarns o~ this invention
relative to the comparative yarn samples re~lect a
characteristically dirferent molecular micro-structure o~
the yarns Or this invention. There~ore, it is believed
3 o that the nylon BCF products treated in the device of Fig 2
are distinctly different and novel compared to the same
nylon BCF yarn treated in known conventional devices or
not treated at all. It is believed that the differences
between the novel nylon heat-treated products and
conventional nylon heat-treated products may be related to
the novel process steps Or the invention where the yarn is
treated in the rorm Or a wad, and in some part to the use
o~ s~lr~rhP~ted 6team at low ~Le~-lLt: as the pre~erred
L. ~:~li L rluid in the device.
23
-
WO95/16065 ;~ 6i PCT/US94113995
More p~rticularly, these yarn products may be made
in accordance with the following method:
a) heating the yarn with sl~rPrho~ted steam;
b) forwarding the yarn with the superheated steam
5 into an elongated chamber, said chamber having an
imperf orate f irst portion and a second portion, such that
a loosely foldea wad of yarn is formed within the
imperforate first portion of said chamber and contained
within the second portion;
lo c) forcing the sl~r~-h~ted steam through the wad in
the first portion of the chamber;
d) venting the sllrorhP~ted steam through a
perforate third portion of said chamber int~ te the
f irst and second portions;
e) cooling the yarn within the second portion of
said chamber; and
~) removing the yarn from the chamher.
Such products are also po~ hle when a cool i~luid jet is
added to the process and/or a supply of second s~rPrh~nted
20 steam is ndded as ~ ~ scl~c~e~ above.
