BACKGROUND OF THE INVENTION
Technical Field
-
The present invention relates to a method for winding
an elastic yarn on a tapered bobbin in a favorable corn-like
form. A cone of an elastic yarn obtained has a superior
unwinding character, and can provide a wound yarn body of
an elastic yarn having a form of corn suitable for supplying
a yarn that is used in production field for industrial
materials such as paper diaper and production fields for
warp knitting and warping.
Prior Art
-
A wound yarn body having a corn form obtainable by
winding a yarn on a tapered bobbin with the yarn being
traversed, is widely applied in winding of an usual spun
yarn and a synthetic fiber yarn such as polyester and nylon,
because it has a superior unwinding character when a yarn
is taken out along the direction of an end face of cone from
a fixed cone. However, since winding velocity of a bobbin
is different between a larger diameter side and a smaller
diameter side when the yarn is wound in a cone form, a tension
of winding becomes higher at a larger diameter side of the
bobbin where a winding velocity is higher, and a tension
of winding becomes lower at a smaller diameter side of the
bobbin where a winding velocity is lower. Thus, there is
a problem that a difference in tension of winding is generated
between a larger diameter side and a smaller diameter side.
This problem does not cause a practically serious obstacle
with yarns having a low elongation which are conventionally
used as stated above, but with yarns having a high elongation
and low stress such as an elastic yarn of a bare polyurethane,
winding on a tapered bobbin has not been employed because
wound form becomes unfavorable due to the difference in
tension of winding generated in winding on a tapered bobbin.
-
With regard to an elastic yarn, a cone of an elastic
yarn for a paper diaper, which has a superior wound form
and unwinding character with a winding amount of not lower
than 1.5 kg and a value of (winding thickness) / (winding
width) of not lower than 0.4, is known (see Patent reference
1). Said cone is suitable for unwinding the elastic yarn
while the cone is revolved, but has a drawback, that is,
a problem that the elastic yarn is caught by a lug of the
cone resulting in a yarn breakage and the like, when the
elastic yarn is unwound along the direction of an end face
of the cone from the fixed cone. To improve such a drawback
of the cone as described above, a cone of an elastic yarn
which has a value of (winding thickness) / (winding width)
of lower than 0.4 using an elastic yarn comprising a dry
spun polyurethane-urea is also known (see Patent reference
2). However, each of these inventions relates to a parallel
cheese as a fundamental form thereof, and when an elastic
yarn is unwound along the direction of an end face of the
cone from the fixed cone, an unwinding resistance is larger
compared with that from a cone cheese, in particular, in
the case of an elastic yarn of a bare polyurethane and the
like, the large unwinding resistance causes problems such
as yarn breakage and irregular feed tension.
- Patent reference 1: JP-B-5-50429
- Patent reference 2: JP-A-11-157750
-
DISCLOSURE OF THE INVENTION
-
An object of the present invention is to provide
a method for producing a cone of an elastic yarn, wherein
an irregular tension in winding, that is, a difference of
tension for winding between a larger diameter side and a
smaller diameter side in a direction of width of a tapered
bobbin generated in winding an elastic yarn having a high
elongation and a low stress on a tapered bobbin, has been
solved, in order to obtain a cone of an elastic yarn having
a superior form and an unwinding character without exhibiting
unfavorable winding of a cone.
-
The inventors of the present invention intensively
studied to solve the above-described problem paying
attention on adjusting a position of traverse support guide,
and thus accomplished the present invention.
-
Namely, the present invention provides a cone of
an elastic yarn obtainable by winding an elastic yarn on
a tapered bobbin with the yarn being traversed, wherein an
average value of unwinding resistance of an elastic yarn
from said cone of an elastic yarn is in a range of 3.2 to
3.4 g. In the present invention, an elastic yarn is wound
on a tapered bobbin with the elastic yarn being traversed
to produce a cone of an elastic yarn, wherein a position
of traverse support guide is moved so that a ratio (V1 /
V2) of winding velocity (V1) at a smaller end face of a cone
of the tapered bobbin to a winding velocity (V2) at a larger
end face of a cone of the tapered bobbin and a ratio (L2
/ L1) of a linear distance (L2) between a traverse support
guide and a larger end face of a cone of the tapered bobbin
to a linear distance (L1) between a traverse support guide
and a smaller end face of a cone of the tapered bobbin become
nearly equal.
-
Here, it is preferable that the ratio (V1 / V2) of
winding velocity (V1) at a smaller end face of a cone of
the tapered bobbin to a winding velocity (V2) at a larger
end face of a cone of the tapered bobbin and the ratio (L2
/ L1) of a linear distance (L2) between a traverse support
guide and a larger end face of a cone of the tapered bobbin
to a linear distance (L1) between a traverse support guide
and a smaller end face of a cone of the tapered bobbin,
satisfies the following relation:
0.85 ≦ V1L1 / V2L2 ≦ 1.15.
BRIEF DESCRIPTION OF THE DRAWINGS
-
- Fig. 1 is a conceptual drawing of a bobbin driven
type of winding machine equipped with a detection sensor
and a control equipment to wind an elastic yarn on a tapered
bobbin.
- Fig. 2 is an explanatory drawing to illustrate
positional relations and linear distances between each part
of a tapered bobbin and a traverse support guide.
- Fig. 3 is a graph showing a correlation when a linear
distance between a larger end face of the tapered bobbin
and a traverse support guide is continuously adjusted in
accordance with a change of a yarn layer thickness of the
cone of an elastic yarn.
- Fig. 4 is a graph showing a correlation when a linear
distance between a larger end face of the tapered bobbin
and a traverse support guide is intermittently adjusted in
accordance with a change of a yarn layer thickness of the
cone of an elastic yarn.
- Fig. 5 is an explanatory drawing to illustrate
positional relations of a cone of an elastic yarn, a
plate-like yarn guide, an apparatus for measuring unwinding
resistance (a tension meter), and a draw roller when the
cone of an elastic yarn is unwound.
- Fig. 6 is an explanatory drawing to illustrate a
state of ballooning in the vicinity of a yarn layer thickness
of 0.08 m when a wound body of an elastic yarn having a form
of a parallel cheese is unwound.
- Fig. 7 is an explanatory drawing to illustrate a
state of ballooning in the vicinity of a yarn layer thickness
of 0.04 m when a wound body of an elastic yarn having a form
of a parallel cheese is unwound.
-
BEST MODE FOR CARRYING OUT THE INVENTION
-
Elastic yarn used in the present invention includes
a polyurethane type of elastic yarn, a polyether type of
elastic yarn, a polyester type of elastic yarn, a
polyether-ester type of elastic yarn, a polyamide type of
elastic yarn, a polycarbonate type of elastic yarn, a
polybutylene terephthalate type of elastic yarn, and an
elastic yarn obtainable by conjugating at least one of these
elastic yarns and other materials. In particular, the effect
of the present invention is remarkably exhibited when a bare
polyurethane type of elastic yarn is used, which has a high
elongation and a low stress and tends to easily tangle each
other due to a large coefficient of friction of yarn surface.
The elastic yarn may be either of a monofilament or a
multifilament, but a multifilament is preferable in the
present invention. Further, the elastic yarn may be adhered
with a surface treatment agent such as a lubricant, or may
be a bare elastic yarn. With regard to fineness thereof,
an elastic yarn having such a wide range as 70 to 1,200 denier
can be used.
-
Wound yarn body of an elastic yarn with a cone form,
to which the present invention relates, may be either of
a usual cone form wherein winding is performed with almost
the same width from the beginning to the end of winding and
a so-called pineapple form wherein a winding width becomes
gradually narrower as winding progresses from the beginning
to the end thereof. Taper angle of a tapered bobbin used
in the present invention may be, for example, in a range
of 3°30' to 9°15' as usually used.
-
Cone of an elastic yarn of the present invention
is produced according to the method described below, and
a cone of an elastic yarn obtained has a specified value
of unwinding resistance. Namely, an average value of the
unwinding resistance is preferably 3.2g to 3.4 g. In
particular, in a case of a bare polyurethane elastic yarn,
a value less than 3.2 g tends to cause unwinding by inertia
due to a too small unwinding resistance, resulting in problems
such as entanglement of the yarn. Contrary, a value over
3.4 g tends to cause yarn breakage or hinder smooth supply
of the yarn.
-
Further, a deviation of unwinding resistance
represented by the equation shown below is preferably 0.16
or less. A deviation over 0.16 is not preferable because
a length of unwound elastic yarn is not stabilized due to
a large dispersion of unwinding resistance, and for example,
when an elastic yarn is used on a paper diaper manufacturing
machine or a warp knitting machine, poor quality of a paper
diaper or a warp knitting fabric produced may be resulted.
Deviation = (Maximum value - Minimum value) Average value
-
Unwinding resistance of an elastic yarn of the corn
is measured using a unwinding resistance measuring equipment.
For example, as described in Examples hereinbelow, an
unwinding resistance is obtained by holding horizontally
a corn of elastic yarn 11 rewound on a tapered bobbin, taking
up the yarn at a velocity of 150 m/min through a plate-like
yarn guide 12 equipped at the position apart by 0.46m from
the rear end of the bobbin by a pair of rollers 13, 13 equipped
at the position apart by 0.23m from said plate-like yarn
guide 12, and measuring a tension of the elastic yarn by
a tension meter 14 [model: PLS-0.2KC, made by NIDEC-SHIMPO
CORPORATION] equipped at the position apart by 0.11m from
said plate-like yarn guide 12.
-
Winding machine of a bobbin driven type, which is
used for winding an elastic yarn on a tapered bobbin in the
present invention, is composed of a commonly used winding
machine equipped with detection sensors and a control
equipment, and main parts thereof are shown in Fig. 1.
-
The winding machine used in the present invention
may be used for direct winding of a spun elastic yarn, but
is suitable for preferably rewinding from a wound body of
an elastic yarn in a form of parallel cheese wound by the
usual method. As a tapered bobbin, for example, bobbin 6
having a taper angle of 3°30' or the like is used, and said
tapered bobbin 6 is mounted to spindle 7.
-
The spindle 7 is driven by an inverter motor via
a gear device, and preferably has an equipment by which
winding velocity is controlled to be constant even when yarn
layer thickness 5 of a cone of an elastic yarn wound on the
tapered bobbin 6 is increased. It is checked by detection
sensor for number of revolution of touch roller 3 whether
the predetermined winding velocity is maintained or not,
using a control equipment having an arithmetic section where
calculation is performed based on information obtained from
detection sensor for yarn layer thickness 1, detection sensor
for number of revolution of spindle 2, and detection sensor
for number of revolution of touch roller 3, and an output
section from which a signal for maintaining a predetermined
winding velocity is sent.
-
The cone of an elastic yarn to be supplied for
rewinding is fixed by a supporting means which is not shown
in the figure, and elastic yarn 10, via guides such as a
snail wire, is wound on the tapered bobbin 6 under a
predetermined contacting pressure by touch roller 8 in
contact with the tapered bobbin 6, while it is traversed
with traversing device 9 through the traverse support guide
a. In this connection, when the elastic yarn 10 is unwound
from the cone of an elastic yarn to be supplied for rewinding,
preferably a drive roller to positively deliver the yarn
is used to reduce an influence of fluctuation of tension
due to unwinding resistance.
-
As the traversing device 9 used in the present
invention, a type using a traverse guide guiding an elastic
yarn which make a reciprocating motion by a cam roller, or
a type to traverse an elastic yarn using a rotating blade
can be used. Traversing velocity is calculated by an
arithmetic section based on information obtained from
detection sensor for number of revolution of spindle 2 and
detection sensor for traversing velocity 4, so as to maintain
a winding number in a range of winding width from a position
of beginning of winding at the larger diameter side of the
cone and a position of beginning of winding at the smaller
diameter side of the cone at a predetermined value, and a
signal thereof is sent from the output section.
-
In the present invention, the detection sensor for
yarn layer thickness 1 includes an ultrasonic sensor and
a laser sensor, the detection sensor for number of revolution
of spindle 2 includes a photo-sensor and a proximity sensor,
the detection sensor for number of revolution of touch roller
3 includes a photo-sensor and a proximity sensor, and a
detection sensor for traversing velocity 4 includes a
photo-sensor. Each of these sensors used in the present
invention can be appropriately selected from the above
sensors, respectively.
-
Control equipment for a driven bobbin type of winding
machine to wind an elastic yarn on the tapered bobbin 6
is composed of a setting section, an arithmetic section and
an output section. The setting section may be composed of
an input device such as a keyboard and a memory device for
the input values. The data to be input include
form-dependent values of the tapered bobbin used such as
taper angle a, bobbin width F, a linear distance between
the larger end face of bobbin and a position of beginning
of winding at the larger diameter side of the cone of bobbin
E, winding width D (see Fig. 2), and number of revolution
of spindle and winding number in a range where the traverse
guide traverses from a position of beginning of winding of
the cone at the larger diameter side of bobbin to a position
of beginning of winding of the cone at the smaller diameter
side of bobbin, both of which are initially set values.
-
Further, the arithmetic section may be a section
that can calculate (1) a position of the traverse support
guide being traversed via a servomotor based on
form-dependent values of the tapered bobbin, initially set
values of the setting section and information from each
detection sensor, (2) a number of revolution of the spindle
to keep a winding velocity constant, and (3) a traversing
velocity to keep a winding number in a range where the traverse
guide traverses from a position of beginning of winding of
the cone at the larger diameter side of bobbin to a position
of beginning of winding of the cone at the smaller diameter
side of bobbin, always constant. In addition, the output
section may be a section that can output a signal for changing
a number of revolution of the spindle, a traversing velocity,
and a position of the traverse support guide a, based on
results of the calculation performed by the arithmetic
section based on form-dependent values of the tapered bobbin,
initially set values of the setting section and information
from each detection sensor.
-
In the present invention, a position of the traverse
support guide a is determined by calculating so that a ratio
of a winding velocity at the smaller end face of a cone of
the tapered bobbin on which an elastic yarn is wound, to
a winding velocity at the larger end face of a cone of the
tapered bobbin, and a ratio of a linear distance between
the traverse support guide a and the larger end face of a
cone of the bobbin to a linear distance between the traverse
support guide a and the smaller end face of a cone of the
tapered bobbin becomes equal, and providing a direction to
move a position of the traverse support guide a. Hereinafter,
this will be explained by referring to Fig. 2. **Fig. 2
is an explanatory drawing to illustrate a positional relation
of the cone of an elastic yarn wound on a tapered bobbin
having taper angle a and the traverse support guide a, a
positional relation of the center of a spindle and the
traverse support guide a, a linear distance X between the
traverse support guide a and the larger end face of the tapered
bobbin, a linear distance L2 between the traverse support
guide a and the larger end face of cone of the tapered bobbin
c, and a linear distance L1 between the traverse support
guide a and the smaller end face b of a cone of the tapered
bobbin.
-
Winding velocity V1 (m/sec) at the smaller end face
of a cone of the tapered bobbin in the present invention
is defined by the following equation (1) from diameter A
(m) of the bobbin at a position of beginning of winding of
a cone at the smaller diameter side of the tapered bobbin,
yarn layer thickness G (m) of a corn, traversing velocity
I (m/sec) and number of revolution of the spindle SP
(number/sec).
V1 = {[(A + 2G) p × SP]2 + I2 }1/2
-
Winding velocity V2 (m/sec) at the larger end face
of a cone of the tapered bobbin in the present invention
is defined by the equation (2) shown below from diameter
B (m) of the bobbin at a position of beginning of winding
of a cone of the larger diameter side of the tapered bobbin,
yarn layer thickness G (m) of a cone, traversing velocity
I (m/sec) and number of revolution of the spindle SP
(number/sec).
V2 = {[(B + 2G) p × SP]2 + I2 }1/2
-
In addition, as stated in the present invention,
a cone having a favorable form and a superior unwinding
character can be obtained by calculating a position of the
traverse support guide a, number of revolution of the spindle
SP and traversing velocity I so that a ratio (L
2 / L
1) of
linear distance L
2 (m) between the traverse support guide
a and the larger end face c of a cone of the tapered bobbin
to linear distance L
1 (m) between the traverse support guide
a and the smaller end face b of a cone of the tapered bobbin
becomes equal to a ratio (V
1 / V
2) of winding velocity V
1
(m/sec) at the smaller end face of a cone of the tapered
bobbin, on which an elastic yarn is wound, to winding velocity
V
2 (m/sec) at the larger end face of a cone of the tapered
bobbin, that is, so as to satisfy the following equation
(3), based on information obtained from detection sensor
for yarn layer thickness 1, detection sensor for number of
revolution of spindle 2, and detection sensor for traversing
velocity 4 , and outputting the results to determine a position
of the traverse support guide a.
V1 / V2 = L2 / L1
Wherein,
- V1: winding velocity at the smaller end face of a cone
of the tapered bobbin (m/sec);
- V2: winding velocity at the larger end face of a cone
of the tapered bobbin (m/sec);
- L1: Linear distance (m) between the traverse support
guide a and the smaller end face b of a cone of the bobbin;
and
- L2: Linear distance (m) between the traverse support
guide a and the larger end face c of a cone of the bobbin.
-
-
Here, the linear distance L2 (m) between the traverse
support guide a and the larger end face c of a cone of the
bobbin is represented by the equation (4) below, provided
that a linear distance between the larger end face C of the
bobbin and the traverse support guide a is X (m), a linear
distance between the larger end of the bobbin and a position
of beginning of winding of a cone at the larger diameter
side of the bobbin is E (m), a linear distance of the center
of spindle and the traverse support guide a is H (m) , a diameter
of the bobbin at the position of beginning of winding of
a cone at the larger diameter side of the tapered bobbin
is B (m), and a yarn layer thickness of the cone is G (m).
L2 = {(X - E)2 + [H - (B / 2 + G)]2 }1/2
-
Further, a linear distance L1 (m) between the
traverse support guide a and the smaller end face b of a
cone of the bobbin also is represented by the equation (5)
below, provided that a winding width is D (m), a diameter
of the bobbin at the position of beginning of winding of
a cone at the smaller diameter side of the tapered bobbin
is A (m).
L1 = {(D + E - X)2 + [H - (A / 2 + G)]2 }1/2
-
Further, the distance from the center of spindle
and the traverse support guide H (m) can be appropriately
determined depending on a distance between each of bobbins
mounted on a bobbin driven type of winding machine.
-
A position of the traverse support guide of the
present invention is determined by the following procedures.
First, a taper angle (a) which is a form-dependent value
of the bobbin used, a width of the bobbin F (m), a distance
between a larger end of the bobbin and a position of beginning
ofwinding E (m), a wound width D (m), andanumber of revolution
of a spindle SP0 (number/see) and a winding number where
a traverse guide transfers from a larger diameter side of
the bobbin to that at a smaller diameter side thereof, both
of which are initially setting values, are input. A diameter
A (m) of the bobbin at the position of beginning of winding
in a smaller diameter side of the bobbin, and a diameter
B (m) of the bobbin at the position of beginning of winding
in a larger diameter side of the bobbin, are calculated from
the taper angle (a), the width of the bobbin F (m) , a distance
between a larger end of the bobbin and a position of beginning
of winding E (m), and a wound width D (m), which were input,
and an initial velocity of traverse I0 (m/sec) is calculated
from an initial number of revolution of spindle SP0
(number/see) and a winding number during the traverse guide
travels from a larger diameter side of the bobbin to a smaller
diameter side thereof. Next, supposing that a yarn layer
thickness of a cone at the beginning of winding G0 = 0 in
the equations 1 and 2, a ratio (V1 / V2) of a winding velocity
V1 (m/sec) at a smaller end face of the tapered bobbin, to
a winding velocity V2 (m/sec) at a larger end face of the
tapered bobbin, is calculated. Then, a position of the
traverse support guide X0 is calculated so that a ratio (L2
/ L1) of a linear distance L2 (m) between a traverse support
guide a and a larger end face c of a cone of the bobbin to
a linear distance L1 (m) between a traverse support guide
a and a smaller end face b of a cone of the bobbin becomes
equal to the ratio (V1 / V2), namely L2 / L1 = V1 / V2, and
is determined by selecting a positive value thereof.
-
In the equations 4 and 5, the diameter A (m) of the
bobbin at the position of beginning of winding in a smaller
diameter side thereof, and the diameter B (m) of the bobbin
at the position of beginning of winding in a larger diameter
side thereof, are values obtainable by the calculations as
stated above, and a wound width D (m), a distance between
a larger diameter of the tapered bobbin and a position of
beginning of winding of the cone in a larger diameter side
thereof E (m), and a linear distance of a spindle center
and a traverse support guide H (m) are the values initially
input. Therefore, a ratio (L2 / L1) of a linear distance
L2 (m) between a traverse support guide a and a larger end
face c of the cone of a bobbin to a linear distance L1 (m)
between a traverse support guide a and a smaller end face
b of the cone of a bobbin is a function of a yarn layer thickness
of the cone G (m) and a linear distance between a larger
end face of a bobbin and a traverse support guide X (m).
Here, since the yarn layer thickness of the cone G (m)
increases with time, L2 / L1 varies with a linear distance
between a larger end face of a bobbin and a traverse support
guide a X (m). L2 / L1 is determined by calculating V1 /
V2 , and a corresponding linear distance between a larger
end face of a bobbin and a traverse support guide X (m) becomes
a solution of a quadratic equation, and the value thereof
is essentially a positive one when a position of a traverse
support guide at the beginning of winding is assumed to be
X0 (m). A taper angle of the tapered bobbin used, a diameter
of the bobbin and a width of the bobbin, may be appropriately
selected, so long as the position of a traverse support guide
at the beginning of winding X0 (m) is a positive value.
-
After the beginning of winding, a position of a
traverse support guide X (m) and linear distance between
a larger end face of a bobbin are determined in the same
manner as of the procedures used for the beginning of winding
except that values measured by each sensor are used as a
yarn layer thickness of the cone G (m) , a traversing velocity
I (m/sec) and a number of revolution of a spindle SP
(number/sec). A position of a traverse support guide is
preferably controlled continuously as shown in Fig. 3, but
may be controlled stepwise in accordance with a yarn layer
thickness of the cone as shown in Fig. 4 within a range not
affecting winding form and unwinding character.
-
Namely, in the present invention, a position of a
traverse support guide is controlled so that the relation
of L2 / L1 = V1 / V2 is satisfied as described above, but
the control may be performed continuously or stepwise within
a certain range. Accordingly, in the present invention,
the relation of L2 / L1 = V1 / V2 is not necessarily required
to be satisfied, but the both values are required to be almost
same, and for example, the values within the following range
are acceptable. When a value of the ratio
0.85 ≦ V1 L1 / V2 L2 ≦ 1.15
is smaller than 0.85, namely, a tension of a smaller diameter
side is smaller than that of a larger diameter side, loose
winding or wrinkles occurs at an end face of the smaller
diameter side, and bulge winding, cob-webbing and the like
occurs at a larger end face. On the other hand, when a value
of the ratio is larger than 1.15, namely, a tension of a
smaller diameter side is larger than that of a larger diameter
side, wavy edges or cob-webbing occurs at a smaller end face,
and thus a wound package having a favorable corn form cannot
be obtained.
-
Conventionally, when a yarn having a high elongation
and a low stress such as a polyurethane elastic yarn was
wound on a tapered bobbin, there was a remarkable influence
due to a difference in winding tension between a larger
diameter side and a smaller diameter side of the tapered
bobbin, and if a winding tension at a smaller diameter side
of the bobbin was kept properly, a winding tension at a larger
diameter side of the bobbin became excessively large,
resulting in a problem of unfavorable winding such as
traversing-off often occurred. Contrary, if a winding
tension at a larger diameter side of the bobbin was kept
properly, a winding tension at a smaller diameter side of
the bobbin became weak, resulting in a tendency of often
occurrence of loose winding or wrinles. Such a phenomenon
became more remarkable as a winding amount increased, or
as a taper angle of the tapered bobbin increased. However,
in the present invention, as stated above, by winding with
a position of a traverse support guide being moved, a cone
of a polyurethane elastic yarn having a favorable form and
an excellent unwinding character can be obtained.
-
Winding amount of a cone of an elastic yarn obtained
by the present invention is not particularly limited, and
may be not only 500 g to 1.5 kg of an usual winding amount,
but also a winding amount of a corn of not lower than the
range. In particular, the method of the present invention
is suitable for a winding amount of not lower than 1.0 kg,
and can be suitably used in various fields.
EXAMPLES
-
Hereinbelow, the present invention will be
explained in detail by referring to Examples, but is not
construed to be limited to this scope. In the Examples,
a winding tension of a cone of elastic yarn having a form
of cone was evaluated by measuring a value of unwinding
resistance during unwinding an elastic yarn from a cone of
elastic yarn. Values of unwinding resistance in these
Examples were measured by using an apparatus for measuring
an unwinding resistance as described below, and a deviation
of unwinding resistance (a dispersion of unwinding
resistance values) was calculated from the measured values
obtained.
Method for measuring by using an apparatus for measuring
unwinding resistance and an equation for calculating a
deviation
-
As shown in Fig. 5, unwinding resistance was obtained
by holding horizontally a corn of elastic yarn 11 rewound
on a tapered bobbin, taking up the yarn at a velocity of
150 m/min through a plate-like yarn guide 12 equipped at
the position apart by 0.46m from the rear end of the bobbin
by a pair of rollers 13, 13 equipped at the position apart
by 0.23m from said plate-like yarn guide 12, and measuring
a tension of the elastic yarn by a tension meter 14 [model:
PLS-0.2KC, made by NIDEC SHIMPO CORPORATION] equipped at
the position apart by 0.11m from said plate-like yarn guide
12 at 3 points of 40 mm, 20 mm and 5 mm in yarn layer thickness
of a corn of elastic yarn for 30 sec. per each point. A
deviation of unwinding resistance values was calculated from
the maximum value, the minimum value and the average value
of the unwinding resistance obtained by the following
equation (6).
Deviation = (Maximum value - Minimum value)Average value
Example 1
-
Apolyurethane elastic yarn of 46.62 tex [Trade name:
FUJIBO SPANDEX, manufactured by Fuji Spinning Co., Ltd.]
having a weight of 3.0 kg, which was wound in a form of parallel
cheese on a cylindrical bobbin and free of lubricant, was
prepared. Then, as initially set values, a taper angle a
= 3°30' which is a form-dependent value of the bobbin used,
a smaller diameter of the bobbin = 0.047 m, a larger diameter
C of the bobbin = 0.075 m, a width F of the bobbin = 0.2286
m, a linear distance E between a larger diameter end of a
bobbin and a position of beginning of winding at a larger
diameter side of a cone thereof = 0.015 m, a winding width
D = 0.195 m, a linear distance H between a spindle center
and a traverse support guide = 0.2 m, an initial number of
revolution of a spindle SP0 = 24.77 number/see, and a winding
number during a period of the traverse guide moving from
a larger diameter side of the bobbin to a smaller diameter
side thereof = 3.25, were input. Arithmetic values of a
diameter A of the bobbin at the position of beginning of
winding of a cone of a smaller diameter side of the tapered
bobbin = 0.0493 m, a diameter B of the bobbin at the position
of beginning of winding of a cone of a larger diameter side
of the tapered bobbin = 0.0732 m, and an initial traversing
velocity I0 = 1.49 m/sec, which were calculated from the
initially set values input, were obtained. The arithmetic
values obtained and an initial yarn layer thickness of a
cone G0 = 0 m, were substituted in said equations (1) and
(2), and calculated to obtain the arithmetic values of the
winding velocity V1 at a smaller end face of the tapered
bobbin 4.12 m/sec and the winding velocity V2 at a larger
end face of the tapered bobbin 5.88 m/sec.
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Calculation was performed by substituting the
arithmetic values of a ratio of velocities V1 / V2 = 0.70
obtained in said equations (4) and (5) to obtain a linear
distance between a larger end face side of a bobbin and a
traverse support guide of X0 = 0.049 and -0.392. Adopting
the positive value thereof, the traverse support guide was
moved to a position of 0.049 m from a larger end face of
a tapered bobbin by using a servomotor. Then, a number of
revolution of a spindle was controlled to become an average
speed 5.0 m/sec = 300 m / min of a winding velocity V1 =
4.12 m/sec at a smaller end face of a cone of the tapered
bobbin and a winding velocity V2 = 5.88 m/sec at a larger
end face of a cone of the tapered bobbin, and a traversing
velocity was controlled to maintain a winding number 3.25
during a period of the traverse guide moving from a larger
diameter side to a smaller diameter side, and further a
position of the traverse support guide was controlled so
that a ratio (L2 / L1) of a linear distance L2 (m) between
a traverse support guide, which varied with an increase of
a yarn layer thickness of a cone, and a larger end face of
a cone of the bobbin to a linear distance L1 (m) between
a traverse support guide and a smaller end face of a cone
of the bobbin, became equal to a ratio (V1 / V2) of a winding
velocity V1 (m/sec) at a smaller end face of a cone of the
tapered bobbin to a winding velocity V2 (m/sec) at a larger
end face of a cone of the tapered bobbin, to produce 3 kg
of a cone of polyurethane elastic yarn having a corn form.
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Results of appearance examination on a wound yarn
body of polyurethane elastic yarn having a corn form,
measurements of unwinding resistances at 40 mm, 20 mm, and
5 mm of yarn layer thickness, deviations of unwinding
resistance, and examination on winding states of a
polyurethane elastic yarn in the most inner layer within
a yarn layer thickness of 2 mm, are shown in Table 1.
| Result of appearance examination | Winding form was cone-like and favorable without deformation. |
| Thickness of yarn layer (mm) | Unwinding resistance (g) | Deviation |
| | Maximum | Minimum | Average |
| 40 mm | 3.4 | 2.9 | 3.2 | 0.16 |
| 20 mm | 3.5 | 3.0 | 3.3 | 0.15 |
| 5 mm | 3.6 | 3.1 | 3.4 | 0.15 |
| 2 mm or less or less | Almost uniform tension was obtained without loosening of a polyurethane elastic yarn in the most inner layer. |
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From Table 1, it can be seen that average values
of unwinding resistances are in a range of 3.2 to 3.4, though
those at the beginning of winding tend to have slightly higher
values, and a deviation thereof resides in a range of 0.15
to 0.16. Thus, a wound yarn body of polyurethane elastic
yarn having a cone form and a superior unwinding character
was obtained, and further both of end faces of a corn package
were almost plane-like. Further, an appearance and a winding
state in each yarn layer were also superior.
Comparative Example 1
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Using the same polyurethane elastic yarn of 46.62
tex having a winding amount of 3 kg as in Example 1, and
a tapered bobbin having the same form-dependent value as
in Example 1, 3 kg of a cone of polyurethane elastic yarn
having a corn form was produced at a winding velocity of
300 m/min by using a bobbin driven style of winding machine
with a traverse support guide fixed at a position apart by
0.03 m from a larger end face of a tapered bobbin without
moving.
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In the same way as in Example 1, results of appearance
examination on a wound yarn body of polyurethane elastic
yarn having a corn form, measurements of unwinding
resistances at 40 mm, 20 mm, and 5 mm of yarn layer thickness,
deviations of unwinding resistance values, and examination
on wound states of polyurethane elastic yarn within the most
inner layer of 2 mm of yarn layer thickness, are shown in
Table 2.
| Result of examination examination | Occurrences of bulge winding and wrinkles were observed. |
| Thickness of yarn layer (mm) | Unwinding resistance (g) | Deviation |
| | Maximum | Minimum | Average |
| 40 mm | 4.3 | 3.4 | 3.9 | 0.23 |
| 20 mm | 4.3 | 3.4 | 4.1 | 0.22 |
| 5 mm | 4.4 | 3.8 | 4.2 | 0.14 |
| 2 mm or less or less | Almost uniform tension was obtained without loosening of a polyurethane elastic yarn in the most inner layer. |
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From Table 2, it can be seen that average values
of unwinding resistance are in a range of 3.9 to 4.2, and
the value at the beginning of winding tend to show a higher
value and gradually lower, but deviations of unwinding
resistance are higher compared with those in Example 1. With
regard to results of appearance examination, the appearance
was poor with bulge winding having a wrinkles at the smaller
end face of the bobbin, and thus a cone of a polyurethane
elastic yarn having a favorable unwinding property could
not be obtained.
Comparative Example 2
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By the same way as in Comparative Example 1 except
that a position of the traverse support guide was fixed at
a position apart by 0.11 m from a larger end face of the
tapered bobbin, 3 kg of a wound yarn body of polyurethane
elastic yarn having a cone form was produced at a winding
velocity of 300 m/min by using a bobbin driven type of winding
machine.
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Results of the appearance examination on the cone
of polyurethane elastic yarn having a cone form obtained,
the measurements of unwinding resistances at 40 mm, 20 mm
and 5 mm in yarn layer thickness, the calculations of
deviations of unwinding resistance, and the examination on
wound states of a polyurethane elastic yarn within the most
inner layer within 2 mm of yarn layer thickness, are shown
in Table 3.
| Result of appearance examination | Wound form was favorable without deformation. deformation. |
| Thickness of yarn layer (mm) | Unwinding resistance (g) | Deviation |
| | Maximum | Minimum | Average |
| 40 mm | 4.0 | 3.5 | 3.7 | 0.14 |
| 20 mm | 4.2 | 3.4 | 3.8 | 0.21 |
| 5 mm | 4.3 | 3.4 | 3.8 | 0.24 |
| 2 mm or less | Loose winding of a polyurethane elastic yarn occurred in the most inner layer. |
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From Table 3, it can be seen that average values
of unwinding resistance are in a range of 3.7 to 3.8 and
almost in the same level, but deviations thereof are higher
compared with those in Example 1. The result of appearance
examination was favorable, but loose winding of a
polyurethane elastic yarn was generated in the most inner
layer, and therefore this was not a cone of polyurethane
elastic yarn having a superior unwinding character.
Reference Example
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Using a cone of a polyurethane elastic yarn of 44.62
tex and free of lubricant having a form of parallel cheese
with a winding amount of 3.0 kg, which was used in Example
1, an unwinding resistance was measured by using an apparatus
for measuring unwinding resistance as described in Example,
and deviations were calculated from the results the
measurements. Results are shown in Table 4. A cone of a
polyurethane elastic yarn having a form of parallel cheese
with a winding amount of 3 kg, was wound at a diameter of
bobbin of 0.085 m, a width of the bobbin of 0.1143 m, a winding
width of 0.096 m, and a yarn layer thickness of 0.095 m.
Measurements of unwinding resistance were made at three
points of 80 mm, 40 mm and 5mm.
| Thickness of yarn layer (mm) | Unwinding resistance (g) | Deviation |
| | Maximum | Minimum | Average |
| 80 mm | 9.8 | 2.8 | 4.2 | 1.67 |
| 40 mm | 3.8 | 2.8 | 3.2 | 0.31 |
| 5 mm | 3.5 | 2.9 | 3.1 | 0.19 |
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From Table 4, it can be seen that average values
of unwinding resistance are in a range of 3.1 to 4.2 and
uneven, and deviations thereof are larger and in a range
of 0.19 to 1.67. At a yarn layer thickness of 80mm, ballooning
in unwinding is large as shown in Fig. 6. Although a ballooning
state becomes moderate at a yarn layer thickness of 40 mm
as shown in Fig. 7, but deviations of unwinding resistance
were larger and fluctuation in tension was larger compared
with those of the cone of a polyurethane elastic yarn of
the present invention.
EFFECT OF THE INVENTION
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A wound yarn body of a polyurethane elastic yarn
having a corn form obtainable according to the method of
the present invention does not exhibit an unfavorable form
in appearance, nor loose winding in an inner layer of a cone,
and exhibits a superior unwinding character with less
variation of tension due to a small deviation of unwinding
resistance, and thus has enabled to wind a bare polyurethane
elastic yarn on a tapered bobbin.
INDUSTRIAL APPLICABILITY
-
The cone of a bare polyurethane elastic yarn having
a corn form obtained by the present invention has a superior
unwinding character, a small deviation of unwinding
resistance and a small dispersion of tension, without
exhibiting an unfavorable form in appearance and a loose
batching in the most inner layer of a corn. Further, a winding
amount of a package can be arbitrarily set, in particular,
a cone having a larger winding amount than usual can be
produced. Thus, the cone of the present invention can be
suitably used in a production field for paper diaper and
the like or a production fields for warp knitting and the
like.
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The term 'cheese' used in this specification refers to
the wound yarn package formed by winding yarn onto a bobbin.
The term 'parallel cheese' refers to a wound yarn package
having a substantially cylindrical or tubular shape with
substantially parallel sides. The term 'cone cheese' refers
to a wound yarn package having a substantially frustoconical
or tapered shape with converging sides.
