U.S. patent application number 10/722261 was filed with the patent office on 2004-06-03 for unwinder for as-spun elastomeric fiber.
Invention is credited to Graverson, Jon P., Heaney, Daniel J., Hicks, Dennis, Martin, Kenneth E..
Application Number | 20040104299 10/722261 |
Document ID | / |
Family ID | 32391983 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040104299 |
Kind Code |
A1 |
Heaney, Daniel J. ; et
al. |
June 3, 2004 |
Unwinder for as-spun elastomeric fiber
Abstract
The invention provides an over-end take off device (OETO) for
unwinding elastomeric fiber. The invention further provides a
method for unwinding elastomeric fiber for downstream
processing.
Inventors: |
Heaney, Daniel J.; (US)
; Graverson, Jon P.; (US) ; Hicks, Dennis;
(US) ; Martin, Kenneth E.; (US) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ, LLP
P O BOX 2207
WILMINGTON
DE
19899
US
|
Family ID: |
32391983 |
Appl. No.: |
10/722261 |
Filed: |
November 25, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10722261 |
Nov 25, 2003 |
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10100811 |
Mar 19, 2002 |
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6676054 |
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Current U.S.
Class: |
242/593 ;
242/594; 242/615.3 |
Current CPC
Class: |
B65H 51/32 20130101;
B65H 49/16 20130101; B65H 49/02 20130101; B65H 2701/319 20130101;
B65H 57/16 20130101 |
Class at
Publication: |
242/593 ;
242/594; 242/615.3 |
International
Class: |
B65H 016/02; B65H
057/04 |
Claims
What is claimed is:
1. An unwinder comprising: a) a frame; b) a fiber package holder
affixed to said frame; c) a fiber package held on the fiber package
holder about a rotational axis such that at least one fiber can
unwind from said fiber package in a direction defining an acute
angle with the rotational axis of the fiber package; d) a driven
take-off roll for unwinding said at least one fiber from the fiber
package; and e) a first fiber guide for directing said at least one
fiber as said at least one fiber is unwound from the fiber package,
said first fiber guide defining a fiber guide inlet orifice having
a central axis and positioned on said frame such that: i. a
distance (d) from the first fiber guide to a front end of the fiber
package facing said first fiber guide, measured on the line defined
by the rotational axis of the fiber package, is equal to: 1) at
least about 0.41 meter when said at least one fiber has tack
greater than about 2 grams OETO and less than about 7.5 grams OETO;
or 2) from about 0.71 meter to about 0.91 meter when said at least
one fiber has tack greater than about 7.5; and ii. an angle
(.theta.), defined by the intersection of imaginary lines
corresponding, respectively, to the rotational axis of the package
and the central axis of the fiber guide inlet orifice is equal to:
1) 0.degree. to about 30.degree. when said at least one fiber has
tack greater than about 2 grams OETO and less than about 7.5 grams
OETO; or 2) 0.degree. to about 10.degree. when said at least one
fiber has tack greater than about 7.5 grams OETO.
2. The unwinder of claim 1 further comprising a second fiber guide
positioned between said fiber package and said first fiber guide
for directing said at least one fiber as said at least one fiber is
unwound from the fiber package.
3. The unwinder of claim 2 further comprising a third fiber guide
positioned between said first fiber guide and said driven take-off
roll.
4. The unwinder of claim 3 further comprising a fourth fiber guide
positioned between said third fiber guide and said driven take-up
roll.
5. The unwinder of claim 1 wherein said first fiber guide comprises
comprises a grooved roll.
6. The unwinder of claim 1 wherein said first fiber guide comprises
a circular guide having a wear-resistant surface for contacting the
fiber.
7. The unwinder of claim 6 wherein said wear-resistant surface is
the inner surface of an annulus.
8. The unwinder of claim 1 wherein said first fiber guide is a
static guide.
9. A method for unwinding fiber from a fiber package comprising the
steps of: a. holding the fiber package about a rotational axis such
that at least one fiber can unwind from the fiber package in a
direction defining an acute angle with the rotational axis of the
fiber package; b. unwinding fiber from the fiber package; c.
controlling the direction of said at least one fiber by passing
said at least one fiber through a first static fiber guide having
an orifice with a central axis that is perpendicular to the plane
of the orifice; d. establishing the distance (d) from said first
static fiber guide to a front end of said fiber package facing said
fiber guide, measured on the line defined by the rotational axis of
the fiber package, such that said distance (d) is equal to: i. at
least about 0.41 meter when said at least one fiber has tack of
greater than about 2 grams OETO and less than about 7.5 grams OETO;
or ii. from about 0.71 meter to about 0.91 meter when said at least
one fiber has tack greater than about 7.5 grams OETO; and e.
setting an angle (.theta.), defined by the intersection of
imaginary lines corresponding, respectively, to the rotational axis
of the package and the central axis of said first fiber guide, such
that said angle (.theta.) is equal to: i. 0.degree. to about 300
when said at least one fiber has tack greater than about 2 grams
OETO and less than about 7.5 grams OETO; or ii. 0.degree. to about
100 when said at least one fiber has tack greater than about 7.5
grams OETO.
10. The method of claim 9 further comprising providing a second
fiber guide positioned between said fiber package and said first
static fiber guide for directing said at least one fiber as said at
least one fiber is unwound from the fiber package.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/100,811, filed March, 19, 2002, currently
pending.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a fiber unwinding device,
and more specifically to a device that minimizes average tension
levels and tension variations of a plurality of elastomeric fibers
being transported to a downstream fiber processing operation.
[0004] 2. Description of Background Art
[0005] The most common method of unwinding fiber from a cylindrical
mandrel (or "package") in manufacturing processes is referred to as
"rolling takeoff". When the package is exhausted the empty mandrel
must be removed and a new package installed. This operation
requires shutting down the manufacturing line causing unproductive
downtime.
[0006] Another method often utilized, the over end takeoff (OETO)
method, allows continuous operation, because the terminating end of
the fiber wound on an active package can be attached to the leading
end of the fiber wound on a standby package. This allows the active
package to be fully exhausted at which point the standby package
becomes the active package, all without any process interruption.
However, unacceptable variations in threadline tension are common
with OETO.
[0007] Research Disclosure, p. 729, November 1995, item #37922,
discloses an OETO system in which elastomeric fiber is passed
through a system comprising a relaxation section and motor driven
nip rolls, before being fed to the manufacturing line. The
relaxation section, extending between the package and the nip
rolls, is stated to suppress tension variations. However, fibers
that exhibit high cohesive forces (generally referred to as "tack")
display unusually high variations in frictional forces and tension
levels as the package unwinds. The slackness of the thread line in
the relaxation region can vary and can result in temporarily
excessive amounts of filament being unwound from the package. This
excess fiber can be drawn into the nip rolls and wound up on itself
leading to entanglement or breakage of the threadline requiring the
manufacturing line to be stopped. The high level of tack
contributes to the possibility of the excess fiber adhering to
itself and to the nip rolls. The OETO device can also be configured
such that the fiber horizontally traverses the relaxation section.
In this case, the fiber then travels through nip rolls whose axes
are vertical. However, in this configuration, the fiber in the
region between the package and the nip rolls can sag. This sagging
allows the threadline position on the nip rolls to become unstable
and can result in interference between adjacent threadlines.
[0008] U.S. Pat. Nos. 3,797,767; 3,999,715 and 6,158,689 disclose
the use of spirally grooved rolls in fiber winding machines in
order to impart a specified pitch angle to a fiber as it is wound
on a package. The use of grooved rolls for maintaining positional
stability among a plurality of thread lines on a single roll is not
described.
[0009] The aforementioned problems make the processing of high
tack, elastomeric fibers particularly problematic. Fiber tack and
its associated problems have been addressed by using topical fiber
additives (prior to winding) or by unwinding the package and
re-winding it on a new mandrel. However, both approaches add
additional expense. Furthermore some applications (such as diaper
manufacturing) require the use of as-spun fiber that is
substantially finish-free and, consequently, exhibits high
tack.
[0010] A fast and reliable method of removing high tack elastomeric
fiber from a package is still needed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 schematically illustrates the fiber unwinding test
equipment used to obtain the data in Examples 1-4.
[0012] FIG. 2 shows a perspective drawing of a preferred embodiment
of an OETO unwinding device.
[0013] FIG. 3 illustrates a perspective view of a portion of an
unwinding device of the invention including some of the packages,
threadline guides and the first driven roll.
[0014] FIG. 4 is a top view of an unwinding device of the
invention.
[0015] FIGS. 5A and 5B, are back and side views, respectively, of
an unwinding device of the invention.
SUMMARY OF THE INVENTION
[0016] The present invention provides, in a first embodiment, an
unwinder comprising
[0017] a) a frame;
[0018] b) a fiber package holder affixed to said frame for holding
a package of fiber about a rotational axis such that at least one
fiber can unwind from said fiber package in a direction defining an
acute angle with the rotational axis of the fiber package;
[0019] c) a driven take-off roll for unwinding fiber from the fiber
package at a predetermined take-off rate:
[0020] d) a first fiber guide for directing fiber unwound from the
fiber package towards the driven take-off roll, said first fiber
guide positioned on said frame such that;
[0021] i. a distance (d) from the first fiber guide to the end of
the fiber package facing such first fiber guide, measured on the
line defined by the rotational axis of the fiber package, is equal
to:
[0022] 1) at least about 0.41 meter for fiber with tack of greater
than about 2 grams OETO and less than about 7.5 grams OETO; or
[0023] 2) from about 0.71 meter to about 0.91 meter for fiber with
tack greater than about 7.5; and
[0024] ii. an angle (.theta.), defined by the intersection of
imaginary lines corresponding, respectively, to the rotational axis
of the package and the central axis of the fiber guide inlet
orifice is equal to:
[0025] 1) 0.degree. to about 30.degree. for fibers with tack
greater than about 2 grams OETO and less than about 7.5 grams OETO;
or
[0026] 2) 0.degree. to about 100 for fibers with tack levels
greater than about 7.5 grams OETO.
[0027] The unwinder of the invention may further include additional
fiber guides between package and said take-off roll.
[0028] The unwinder of the invention preferrably further includes a
second fiber guide positioned between the fiber package and the
first fiber guide for directing fiber unwound from the fiber
package. More preferrably, the unwinder of the invention further
comprises a third fiber guide positioned between the first fiber
guide and the driven take-off roll.
[0029] The unwinder of the invention may also include a fourth
fiber guide positioned between the third fiber guide and the driven
take-up roll.
[0030] At least one of the fiber guides may be a grooved roll or
the driven take-off roll may be a grooved roll.
[0031] In a preferred embodiment, at least one fiber guide is a
static circular guide having a wear-resistant surface for
contacting the fiber. The circular fiber guide preferably has a
wear-resistant inner surface such that the wear-resistant surface
is the inner surface of an annulus.
[0032] In a second embodiment, the invention provides a method for
unwinding fiber comprising the steps of:
[0033] a. holding a fiber package about a rotational axis such that
at least one fiber can unwind from the fiber package in a direction
defining an acute angle with the rotational axis of the fiber
package;
[0034] b. unwinding fiber from the fiber package of step (a) at a
controlled predetermined rate;
[0035] c. controlling the direction of said fiber of step (a) by
passing the fiber through a first fiber guide; and
[0036] d. controlling the distance (d) from said first fiber guide
to the end of said fiber package facing said fiber fiber guide,
measured on the line defined by the rotational axis of the fiber
package, such that said distance (d) is equal to:
[0037] i. at least about 0.41 meter for fiber with tack of greater
than about 2 grams OETO and less than about 7.5 grams OETO; or
[0038] ii. from about 0.71 meter to about 0.91 meter for fiber with
tack greater than about 7.5;
[0039] e. controlling an angle (.theta.), defined by the
intersection of imaginary lines corresponding, respectively, to the
rotational axis of the package and the central axis of said first
fiber guide that is perpendicular to the plane of the orifice, such
that said angle (.theta.) is equal to:
[0040] i. 0.degree. to about 30.degree. for fibers with tack
greater than about 2 grams OETO and less than about 7.5 grams OETO;
or
[0041] ii. 0.degree. to about 10.degree. for fibers with tack
levels greater than about 7.5 grams OETO.
DETAILED DESCRIPTION OF THE INVENTION
[0042] With reference to FIG. 1, a fiber package 10 is maintained
in a desired orientation by a cylindrical rod (not shown). The
diameter of the rod is smaller than the diameter of the open core
of the package such that the package can be slid over the suitably
positioned rod and such that the fiber can be unwound from the
package by over end takeoff. The fiber is then directed, in
sequence, through a static guide 20 having a substantially circular
orifice; a driven roll 30 around which the fiber is wrapped
360.degree., or less; and a second, driven take-up roll or set of
rolls 50. The static guide is typically an orifice whose inner
surface can be a highly polished ceramic material. Such a surface
can provide excellent wear resistance and low friction. The take-up
roll or rolls 50 representing that part of the manufacturing
process equipment to which the fiber is being supplied, is/are
rotated at a speed relatively higher than the first motor-driven
roll, so as to provide the desired draft. A distance (d) between
the package and the static guide, which is at least about 0.43
meter and preferably not more than about 0.91 meter, can be
maintained for operation with high tack fibers. An acute angle
(.theta.), defined by the intersection of the imaginary lines
corresponding, respectively, to the rotational axis of the package
and the central axis of the static guide orifice that is
perpendicular to the plane of the orifice, is preferably maintained
between 0 and about 300 for operation with high tack fibers. Means
for stabilizing the position of the threadline on the first driven
roll can be provided by, for example, use of one or more additional
guides 60, 70, 80 and/or a plurality of grooves in the surface of
the first driven roll 30 wherein said grooves are substantially
perpendicular to the roll axis and substantially parallel to the
direction of travel of the threadline.
[0043] Distances less than 0.41 meter can result in undesirably
large tension variations. These variations can cause process
control difficulties and can also lead to thread line breakages.
Distances longer than 0.91 meter make the unwinding equipment less
compact and ergonometrically less favorable. As the level of tack
exhibited by the fiber increases, the minimum allowable distance,
d, increases. For fibers with tack levels greater than about 2 and
less than about 7.5, d is preferably at least about 0.41 meter; and
for fibers with tack levels greater than about 7.5, d is preferably
at least about 0.71 meter.
[0044] As the level of tack exhibited by the fiber increases, the
maximum allowable angle, .theta., decreases. The directional change
of the threadline, as it passes through the first static guide, as
measured in terms of 0, is preferably limited to between 0.degree.
and about 30.degree. for fibers with tack levels greater than about
2 and less than about 7.5, and between 0.degree. and about 100 for
fibers with tack levels greater than about 7.5. Larger angles can
result in excessive variations in thread line tension and draft, or
even threadline breakage.
[0045] The desired thread line positional stability can be assured
by providing grooves in the surface of the first driven roll. Such
grooves also allow closer spacing of the threadlines, thereby
minimizing the dimensions of the equipment. The resulting stability
of the threadline position also allows operator intervention to
correct a threadline problem, while the process is running, with
less risk of disturbing adjacent thread lines.
[0046] Threadline guides can be used in addition to, or instead of,
grooved rolls to impart thread line stability and to direct the
threadline along a desired path. Of the various threadline guides
available, captive, rolling guides are preferred. The use of a
single, first motor-driven roll described above is found to give
outstanding process performance without the need for employing the
more mechanically complex and expensive nip rolls described in
Research Disclosure, item 37922, cited above. A wrap of 360.degree.
or less of the thread line around the roll minimizes fiber-on-fiber
contact and the possibility of fiber damage associated with such
contact. Less than 360.degree. contact between the thread line and
roll can be achieved by the appropriate positioning of a threadline
guide placed immediately after the roll to lift the fiber off the
roll surface short of a complete 360.degree. wrap.
[0047] The process by which the unwinder of this invention can be
operated involves the following steps, with reference to FIGS. 2,
3, 4, 5A and 5B: a) placing the fiber packages on their respective
mounting rods; b) tying the leading end of fiber from each standby
package 300' or 400' to the trailing fiber end of its corresponding
active package 300 or 400, respectively; c) directing the leading
fiber end of each active package through its respective static
guide 100 or 100', then through a wrap of 360.degree. or less
around the first driven roll 800 and then causing it to be engaged
by a take-up device not shown in FIGS. 2-5 (identified as 50 in
FIG. 1) (this device, typically a driven roll or set of driven
rolls, represents that element of the manufacturing process which
first engages the fiber as it exits the unwinder); d) initiating
rotation of the first driven roll 800 and take-up device (not
shown); while e) controlling the surface speeds of each such that
the surface speed of roll/s (not shown) exceeds that of roll 800 by
the percentage corresponding to the desired fiber elongation (or
draft); f) replacing each active package 300 or 400, as it becomes
exhausted, with what now becomes a standby package; and g) tying
the leading fiber end of this new standby package 300 or 400 with
the trailing end of the now, active package 300' or 400'. Repeating
steps f and g (or b), as required, allows uninterrupted operation.
As previously described, positional stabilization of the
threadlines can be achieved by the use of a grooved roll 800,
and/or additional threadline guides. In the event that a grooved
roll is employed, step c, above, also includes placing each fiber
in its corresponding groove. In the event that additional
threadline guides are employed, additional steps must be added to
the above procedure to thread each fiber through its respective,
additional guides in the sequence that such guides are
encountered.
[0048] FIGS. 2-5A&B illustrate a preferred embodiment of an
OETO unwinding device for high tack spandex fiber. For the purpose
of improved clarity, the threadlines are not shown. As presented in
FIGS. 2, 3 and 4, the OETO fiber unwinding system has the capacity
to feed a manufacturing line with eight (8) threadlines, requiring
a capacity to accommodate sixteen (16) packages. Each threadline
supplied from an active package to the first, static guide 100 or
100' is kept in the horizontal plane. The packages are mounted in
vertical tiers 200, each tier holding four (4) packages 300, 300',
400 and 400'. The four packages are arranged in pairs, each pair
consisting of one active 300 or 400 and one standby 300' or 400'
package.
[0049] With reference to FIGS. 4, 5A and 5B, each threadline leads
from an active package 300 or 400 through a first static guide 100
or 100' and then through a captive rolling guide 500, at the
horizontal center of the unwinding device. All three of these
elements are located substantially on the same horizontal
plane.
[0050] Referring to FIG. 5A, the threadline is then turned up or
down, depending upon the tier from which it originated, to the
vertical center of the unwinding device. At the vertical center of
the unwinding device, each threadlines is fed through its
respective captive rolling guide 600 and then directed horizontally
through its respective static guide 700. Finally, the threadlines
are wrapped 360.degree., or less, around a horizontal driven roll
800. The driven roll 800 (shown in FIG. 3) is illustrated with
eight grooves 900, through which the threadlines run. The groove
depths are 0.38 mm and the spacing between the grooves is 15 mm.
Grooves are an optional feature of horizontal driven roll 800; the
driven roll may alternatively have a smooth surface.
[0051] The following examples include experiments with Lycra.RTM.
XA.RTM. fibers having no topically applied finish.
EXAMPLE 1
[0052] The test equipment used in obtaining the data for this and
the following examples, could be configured in various ways, such
as optionally including or excluding certain design elements and
changing the sequence of certain elements. The equipment
configuration employed for this example, with reference to FIG. 1,
was comprised of the following elements, listed in the order in
which they were encountered by the moving threadline: fiber package
10, static guide 20, first, driven roll 30, tension sensor 40, and
driven take-up rolls 50.
[0053] The test equipment geometry and other experimental test
conditions are summarized below:
[0054] The distances between the static guide and the first driven
roll, between the first driven roll and the tension sensor and
between the first driven roll and the take-up roll were 0.22, 1.94
and 2.1-3.4 meters, respectively. In this example, the first driven
roll, having a diameter of 8.89 cm., was not grooved. The
threadline was maintained in the horizontal plane (relative to
ground), and its directional change within that horizontal plane as
it passed through the static guide, was maintained constant at
0.degree. .theta.. The distance between the package and first guide
was varied. The threadline was wrapped 360.degree. around the first
driven roll. The threadline draft was controlled at 2.15.times.by
maintaining the surface speeds of the first roll at 93.4 meter/min,
and the surface speed of the takeup rolls at 294.3 meters/min.
[0055] Tension data (expressed in grams) were collected with a
Model PDM-8 data logger, and a Model TE-200-C-CE-DC sensor
(Electromatic Equipment Co.). All tension measurements were
averaged over five-minute run time using a data sampling frequency
of approximately 82 samples/sec.
[0056] "Mean range tension" was determined as follows: within every
1.25-second interval of the tension measurement, the minimum and
maximum tension levels were recorded (yielding 103 data points).
Mean range tension was calculated by averaging the differences
(between the minimum and maximum values) over the 5-min run.
[0057] The fiber evaluated in this test was as-spun Lycra.RTM. XA
spandex (a registered trademark of E.I. du Pont de Nemours and
Company) having a linear density of 620 dtex (decigram per
kilometer).
[0058] Table 1 shows the thread line tension variations, as
measured at the sensor, as the distance, d, between the package and
the static guide was varied over a distance between about 0.25 and
0.81 meter.
1TABLE 1 Distance Mean Range Tension Max. Tension (meter) (grams)
(grams) 0.27 16.90 50.00 0.28 17.60 50.00 0.30 17.80 50.00 0.33
16.30 50.00 0.36 16.30 49.00 0.38 14.50 50.00 0.41 13.70 48.40 0.43
13.30 38.00 0.46 12.40 37.10 0.48 12.20 44.70 0.51 11.60 36.30 0.53
11.60 36.70 0.56 11.60 30.40 0.58 11.80 32.60 0.61 10.00 28.80 0.64
10.60 34.30 0.66 10.60 25.30 0.69 10.40 34.30 0.71 10.60 29.80 0.74
10.00 28.40 0.76 10.40 29.40 0.79 10.80 27.80 0.80 10.80 34.50
[0059] Table 1 demonstrates that thread line tension (expressed
either as the mean range or the maximum tension) decreases as the
distance between the package and the static guide is increased.
Minimum tensions, not shown in the table ranged from about 0.6 to
1.4 grams. Unexpectedly, it has been discovered that there is a
minimum distance of about 0.41 meter below which the absolute level
of tension and the tension variability (as observed by plotting,
for example, maximum tension versus distance) rises to an
unacceptably high level identifiable by the occurrence of
threadline breakages which are usually preceded by a relatively
abrupt increase in mean range tension.
EXAMPLE 2
[0060] The same test equipment as described in Example 1, but
configured to more closely correspond to the preferred embodiment
of the OETO unwinder design was utilized. With reference to FIG. 1,
the equipment had the following elements in the order in which they
were encountered by the moving threadline: fiber package 10,
captive rolling guide 60, static guide 20, captive rolling guide
70, first, driven roll 30, captive rolling guide 80, tension sensor
40, and driven take-up rolls 50.
[0061] The distances between the static guide and the first driven
roll, between the first driven roll and the tension sensor, and
between the first driven roll and the takeup rolls were 0.43, 0.51
and 2.43 meters, respectively. The first driven roll was a single
roll having a single groove with a depth of 0.38 mm. The threadline
was again maintained in the horizontal plane. The distance between
the package and the static guide was held constant at 0.65 meter
while the angle, .theta., was varied. Threadline draft was
maintained at 4.times.by controlling the first driven roll and the
takeup rolls, respectively, at surface speeds of 68.6 and 274.3
meters/min.
[0062] In addition to monitoring threadline tension as in Example
1, tension spikes were also recorded. "Tension spikes" are the
average number of sudden increases in tension greater than 25 grams
above baseline tension in a 5-min period.
[0063] Various as-spun Lycra.RTM. XA.RTM. spandex fibers,
exhibiting different levels of tack, were evaluated. Tack levels
were characterized by measuring the OETO tension (in grams) by the
following method: The fiber package and a ceramic pig tail guide
were mounted 0.61 meter apart, such that the axes of each were
directly in line. The fiber is pulled off the package over end at a
threadline speed of 50 meters/min, through the guide, and through a
tension sensor.
[0064] Table 2 shows the threadline tension variations as the angle
.theta. increased; where .theta. is defined as the acute angle made
by the intersection of the imaginary lines corresponding,
respectively, to the rotational axis of the package and the central
axis of the static guide orifice that is perpendicular to the plane
of the orifice.
2TABLE 2 Mean Max. Angle Range Tension Tension Fiber (degree)
Tension (g) (grams) Spikes Tack T-127 0 38.4 174.9 56 620 dtex 5
40.8 176.5 85 Lot 9291 11 BROKE Merge 1Y331 22 BROKE 45 BROKE T-127
0 16.5 118.4 0 620 dtex 5 17.3 119.2 0 Lot 0211 11 17.3 122.4 0
Merge 16398 22 18.8 124.7 0 45 20.4 131.8 0 57 25.1 138.0 1 67 29.0
149.0 9 77 30.6 156.9 11 90 35.3 167.9 14 T-162B 22 32.9 171.8 16
11.368 800 dtex 45 40.8 198.4 53 " Lot 0205 57 44.7 >200 72 "
Merge 16525 T-162C 22 25.9 159.2 0 7.02 800 dtex 45 29.8 176.5 4 "
Lot 0020 57 31.4 169.4 24 " Merge 16600
[0065] Examination of the data in the above table reveals an
unexpected relationship between threadline tension and the angle
between the centerlines of the package and the static guide. As the
angle increases so does thread line tension, and tension spikes
occur more frequently. At sufficiently large angles, thread line
breakage can occur. The sensitivity of thread line tension to the
angle traversed by the thread line as it passes through the guide
is dependent upon the properties of the fiber. The data of Table 2
indicate that fibers characterized by higher tack exhibit higher
sensitivity of thread line tension with respect to this angle. For
some fibers that exhibit an exceptionally high level of tack, the
angle above which thread line breakage cannot be avoided is less
than about 10.degree..
EXAMPLE 3
[0066] The series of runs, using the test equipment described
previously and configured as in Example 2, evaluated the effect of
angle on threadline tension for fibers of different tack levels.
The distance, d, between the package and the static guide was
maintained constant at 0.65 meter. Threadline draft was maintained
at 4.times.by controlling the first driven roll and the takeup
rolls, respectively, at surface speeds of 68.6 and 274.3
meters/min. All other experimental conditions were as described for
Example 2. The data are summarized in Table 3.
3TABLE 3 Mean Max. Angle Range Tension Tension Fiber (degree)
Tension (g) (grams) Spikes Tack 0 25.1 164.7 2 7.02 T-162C 5 25.1
157.7 0 " 800 dtex 11 27.5 156.9 0 " Merge 16600 22 28.2 160.0 0 "
Lot 0020 45 36.9 182.8 16 " 57 42.4 196.1 59 " 67 47.8 >200.0
127 " 77 BROKE 0 18.0 150.6 0 1.408 T-162C 5 15.7 142.8 0 " As-spun
11 17.3 143.5 0 " 840 den 22 14.9 140.4 0 " Merge 16795 45 14.9
138.8 0 " Lot 1019 57 " 67 15.7 140.4 0 " 77 16.5 144.3 0 " 90 17.3
145.1 0 " 0 29.0 171.8 13 11.368 T-162 B 5 32.2 172.6 10 " 800 dtex
11 36.1 184.3 42 " Merge 16525 22 39.2 >200.0 43 " Lot 0205 45
52.6 >200.0 126 " 57 BROKE "
[0067] The high tack fibers tested in this series of runs are the
same as two of the fibers tested in Example 2. Comparison of the
data for these same fibers in Tables 2 and 3, shows that thread
line tension increases with increasing angle, and thread line
breakage may occur at excessively high angles. (In contrast, fibers
containing finish can be run at angles of up to and including 900
with no increase in thread line tension, no occurrence of tension
spikes and no thread line breaks. When Lycra.RTM.XA.RTM. T-162C
fiber, 924 dtex den, merge 16795(lot 1019), finish, having a tack
of 1.406, was run at angles of 0-90.degree., there was no
threadline tension increase and no tension spikes.)
[0068] These data demonstrate that limiting the angle the thread
line traverses as it passes through the first static guide provides
uninterrupted manufacturing processing even for high tack fiber
threadlines.
EXAMPLE 4
[0069] This series of runs using the test equipment described
previously and configured as in Example 2, evaluated the effect of
the distance, d, between the package and the static guide on
threadline tension for fibers of different tack levels. The angle,
.theta., was maintained constant at 220. The threadline draft was
controlled at 4.times. and the take-up speed at 274.3 meters/m
in.
4TABLE 4 Mean Max. Distance Range Tension Tack Fiber (meter)
Tension (g) (grams) (grams) T-162 C 0.20 56.5 >200 7.02 As-spun
0.30 44.7 200.0 " 720 den 0.41 32.2 182.0 " Merge 16600 0.51 32.2
174.9 " Lot 0020 0.61 31.4 181.2 " 0.71 29.0 173.3 " 0.81 29.8
178.8 " 0.91 32.2 173.3 " 1.02 29.0 167.9 " T-162 B 0.20 BROKE
BROKE 11.368 As-spun 0.30 57.3 >200 " 720 den 0.41 56.5 >200
" Merge 16525 0.51 55.7 >200 " Lot 0205 0.61 56.5 200.0 " 0.71
56.5 200.0 " 0.81 48.6 200.0 " 0.91 50.2 200.0 " 1.02 52.6 200.0
"
[0070] The test results for these fibers show the minimum distance
between the package and the fixed guide below which the threadline
tension and mean range tension increase unacceptably. The value of
this minimum depends upon the tack level of the fiber being tested.
In contrast, there is essentially no effect of package-to-static
guide distance on the lower tack Lycra.RTM. spandex. These results
reinforce the difficulty in maintaining smoothly running process
conditions with high tack fibers.
[0071] The present invention allows successful control of processes
utilizing such fibers.
EXAMPLE 5
[0072] A test of the operation of the unwinder system of this
invention, as pictured in FIGS. 2-5, was conducted under commercial
production conditions using fibers that were characterized by
different levels of tack. Table 5 summarizes these test results.
Data were obtained as in previous examples, except that each of the
tension measurements reported is the average of a minimum of 4
separate measurements, each measurement consisting of one tube
running for a 10-min period. Similarly, each number of tension
spikes, as reported in Table 5, is the average number of spikes
greater than 25 grams above baseline tension in a 10-min period.
Measurements were made on packages that were nearly full (surface)
or nearly empty (core). Core measurements are those with about
1.6-cm thickness of yarn remaining on the tube. Of the 5 as-spun
fibers run, 4 ran with no operational problems. One fiber sample,
Merge 1Y331, did result in an unacceptable occurrence of tension
spikes. That fiber demonstrated an unusually high level of tack,
even for as-spun fiber, as evidenced by the fact that the mean
range tension was over 60% higher than that of the fiber exhibiting
the next highest level of tack.
5TABLE 5 Mean Linear Yarn Range Max. Density Location Speed Yarn
Tension Tension Tension Fiber (dtex) on Tube (ft/min) Draft (grams)
(grams) Spikes Merge 16398 620 Surface 274.3 4X 12.3 100.6 0 Merge
16398 620 Surface 121.9 4X 12.5 96.1 0 Merge 16398 620 Core 274.3
4X 17.5 110.7 0 Merge 16398 620 Core 121.9 4X 16.3 104.1 0 Merge
1Y331 620 Surface 274.3 4X 28.6 151.4 18
* * * * *