JPS60204577A - Polyester fiber package and manufacture thereof - Google Patents

Abstract

PURPOSE:To control the amorphous orientation of a polyester fiber package, by setting a yarn length of 3-40m per unit length of 1m in the axial direction of a bobbin, and setting a taper angle of 25 deg. or less at the end face of the package. CONSTITUTION:In a polyester fiber package, the yield stress is 1.7-2.8g/d, the range DELTAT of the fluctuation in the stretch tension measured in the axial direction of the fiber at 4% of stretch is 0.13g/d or less, the yarn length per unit length of 1m in the axial direction of a bobbin is 3-40m, and the taper angle at the end face of the package is 25 deg. or less. For that reason, the amorphous orientation of the package is controlled to be appropriate.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a package of polyester fiber and a method for producing the same, and more particularly, the present invention relates to a package of polyester fiber and a method for producing the same, and more particularly, it has excellent post-processing passability at high speed, particularly excellent weavability, and is developed into a highly twisted textured fabric. The present invention relates to a polyester fiber that has good graining performance and can produce a woven fabric with uniform grain quality, and a method for producing the same.

[Prior art]

Conventionally, polyester fibers have been supplied to the market in cheese-wound or paan-wound packages. These polyester fibers are obtained mainly by drawing an amorphous undrawn yarn spun at a low speed in a separate step, or by directly drawing the yarn after spinning without winding it up. Such polyester fibers are woven in a post-processing process. However, when conventional polyester fibers are passed through higher-order processes at high speeds, they often break and fluff, and when woven at high speeds, they suffer from sink spots and dyeing. Fabrics may often have defects such as spots,
It has become a big problem. Furthermore, when developed as a textured fabric, not only is the high-order permeability poor, but also the appearance.

The uniformity of the grain is poor, and the grain raising performance varies widely within the fabric, making it difficult to obtain a desirable grained fabric.

After various investigations into the causes of these two major problems in the use of conventional polyester fibers, it was discovered that the two problems, which were thought to be caused by completely different factors, were actually caused by the same cause.

In other words, the above-mentioned problems during high-speed weaving and the problem of grain performance are fundamental problems that are closely related to the internal structural characteristics of conventional drawn yarn, especially the structure of the amorphous part, and in order to solve these problems, Fundamental improvements in fiber internal structural properties are needed.

Conventional drawn yarns have a strong structure by stretching the molecular chains close to their limits and increasing their amorphous orientation, but in order to solve the above problems, it is necessary to loosen this structure and appropriately control the amorphous orientation. It turned out to be effective.

However, in the conventional stretching method in which the yarn is held between rollers, it is not possible to uniformly stretch the yarn while appropriately loosening the amorphous orientation. In addition, although yarns with a relaxed amorphous orientation have a great effect on solving the above two problems, they also have weak mechanical properties due to the low amorphous orientation. As a result, a problem arises in that distortion is likely to be applied during winding, and it has been difficult to obtain a homogeneous package using conventional winding methods.

[Purpose of the invention]

An object of the present invention is to provide a cage for polyester fibers with controlled amorphous orientation, which is applicable to high-speed weaving and has good shear performance, and a method for producing the same.

[Structure of the invention]

The first invention that achieves the above object has a yield point stress of 1.
7 to 2.8 g/d, ΔT was 0.0 during the fluctuation of the stretch tension value measured in the fiber axis direction at 4% stretch.
A package made of polyester fibers with a weight of 13 g/d or less and with substantially no real twist, the package having a unit length in the bobbin axis direction of 1 cr/L) whose yarn length is 3 to 40 cm. The end face of the package is characterized by having a teno (-) angle of less than 25 degrees.

In addition, in the second invention, the polyester yarn discharged from the spinneret is once cooled to a temperature below the rapid glass transition, then introduced into the heating zone again, heated and stretched, and then taken up at a winding speed of 4000.
rn Using a spindle drive type winder for 7 minutes or more, the yarn is traversed with a slow laparth whose traverse speed IT 'cIn/sec satisfies the following formula, without contacting the package being wound with other objects. , yield stress is 1.7
ΔT during fluctuation of stretch tension value measured in fiber axis direction at ~2.8g/d4% stretch is 0.13g4
It is characterized by having the following yarn length in the bobbin axial direction per unit length (1 crrL) of 3 to 40 m, and winding it as a package with substantially no actual twist, V/2400≦T≦ V/180 (in the formula, V is the winding speed m7 minutes).

The present invention will be explained in more detail below.

First, in the polyester fiber package of the present invention, the yield point stress of the polyester fiber is 1.7 to 2.8 g/
d is first essential.

The yield point stress is a physical property value that well represents the amorphous orientation of fibers. If the yield point stress is less than 1.7 g/d, the amorphous orientation is too low, the mechanical properties deteriorate, and the impact during weaving is reduced. It is undesirable because it easily stretches due to force, and when used as a textured fabric, the ability to develop texture is poor. In addition, in the case of fibers with a yield point stress exceeding 2.8 g/d, the amorphous orientation is too high, causing fluff, sink marks, and dyeing spots during high-speed weaving, and unevenness of the grain on the fabric in textured fabrics. It has the disadvantage of reduced performance.

By the way, when attempting to obtain a yarn in which the amorphous orientation is suitably controlled in this manner by conventional stretching methods, uniform stretching cannot be achieved and thick/fine unevenness and internal structure unevenness become large.

In addition, due to the low amorphous orientation of such yarns, external forces are not a problem when winding them, which is not a problem with conventional yarns.

Distortion is also likely to be imparted by impact force.

Therefore, in order to make a practical fiber, it is necessary to prevent deterioration in uniformity during stretching and to minimize distortion during winding.

As a measure of such uniformity, LJc4% measured in the fiber axis direction
In the present invention, it is necessary that the stretch tension during stretching/AT be 0.13 g/d or less, preferably 0.1 g/d or less.

This limit on the stretch tension value serves as a measure of the strain inherent in the system, and polyester fiber packages that do not satisfy the above-mentioned specifications will cause sink spots and dye spots when made into knitted fabrics.

Furthermore, in order to prevent strain distribution from occurring in the package, the unit length of the package in the bobbin axis direction is ICm).
The yarn length wound on the package is 3 to 4 regardless of the winding layer of the package.
It is necessary to control the length to 0m, 5 to 30
m is more preferred.

A package with a yarn length of less than 3 m means that the yarn traverse speed during winding is high, and the actual winding tension at both end surfaces of the package increases and the impact force at the time of folding is too thick.
During winding, a large strain is applied at this end face, resulting in a strain distribution that is so large that it becomes a defect in the knitted fabric as a package. When the yarn length is longer than 40 m, the yarns are too closely spaced, causing fluctuations in the unwinding tension from the package and generation of fuzz, causing problems in higher-order processes.

In order to form such a package, it is necessary to form the package so that the end face of the package has a taper angle of 25° or less.

Therefore, the traverse width of the yarn must be gradually reduced depending on the amount of winding. If the taper angle is greater than 25°, the shoulders tend to sag from the tapered part of the package, making it impossible to form a package with good unwinding properties.

In the present invention, polyester means polyester having ethylene terephthalate units as the main repeating unit, and polyethylene terephthalate is the main target, but
A copolyester copolymerized with a third component may be used as long as it contains 80 molti or more of polyethylene terephthalate. Moreover, the cross-sectional shape of the polyester fiber can be applied to various known irregular cross-sections from a round cross-section.

Next, a method for manufacturing such a polyester fiber package will be described.

As mentioned above, in the polyester fiber of the present invention, the stress at yield point is controlled to be 1 to 2.8 g/d.

However, when using the conventional stretching method in which the yarn is gripped between rollers and the stretching ratio is set low to reduce the amorphous orientation, uniform stretching cannot be achieved, resulting in uneven fiber internal structure and thickness, resulting in poor product quality. It becomes unusable.

In addition, there is a method of high-speed spinning at a spinning speed of 5,000 m/min or more in order to lower the amorphous orientation, but with such a method, the amorphous orientation is too low, the grain development is reduced, and instantaneous problems occur during the weaving process. A new problem arises in that the impact force applied to the material makes it easier to stretch.

Therefore, in order to uniformly draw fibers with a controlled amorphous orientation with a yield point stress of 1.7 to 2.8 g/d, conventional drawing methods and high-speed spinning methods cannot be used. Not applicable. As a result of the research conducted by the present inventors, the most effective means for uniformly drawing fibers with such characteristics is to introduce the yarn into the heating zone again after solidifying it during the spinning process and re-draw it. It has been found. With this method, the withdrawal speed is 40
By setting the speed to 00 m/min or more, the yield point stress is 1.7 to 2.
A yarn with the desired degree of amorphous orientation, characterized by 8 g/d, is obtained under uniform drawing.

By controlling the degree of amorphous orientation in this way, the wrinkle performance in high-twist applications is improved and it becomes possible to handle high-speed weaving, but such fibers are difficult to handle due to their low amorphous orientation. is extremely difficult.

For example, since the amorphous orientation is low, strain is likely to be applied to the inside of the fiber during winding due to impact force or external force that would not cause problems with conventional yarns. To explain this with a specific example, when winding with the conventional cheese method, high-speed traverse is used, but the winding tension is substantially higher at both ends of the traverse than in the center, causing excessive internal strain in the yarn. Make it internal.

Moreover, due to the rapid turn-back of the traverse guide, a large impact force is applied to the yarn, and yarn pooling is likely to occur at both end surfaces, making it easy for large distortions to occur. Therefore,
Both end faces are in a state of large internal strain from the time the winding begins. This tendency is amplified because the traverse speed also increases as the winding speed increases. Such internal distortions appear when fabrics are made and dyed, and cause dyeing spots that deteriorate the quality of the fabrics.

Therefore, the fibers with controlled amorphous orientation of the present invention are
It is important to wind the film in such a way that strain is not applied as much as possible during winding, and that there is no difference in the amount of strain applied depending on the winding position.

For this reason, it is necessary to use a spindle drive type winder as the winder, and to wind the package in a completely non-contact state with other objects.

Even with a spindle drive type winder, it is not advisable to use roller veils that come into contact with the package to control the winding speed, for example. Even for other purposes, if there is a roller-like object that comes into contact with the package, it will press down the package with a certain amount of surface pressure, and the wound threads will be pressed against each other, causing extra strain during winding. Since the threads overlap excessively, the unwinding property becomes poor. That is, in the present invention, it is important that the package being wound up does not come into contact with any other object. Therefore, in order to control the winding speed, the winding tension is detected and the spindle rotation speed is decreased according to the amount of winding to maintain a constant tension, or the pattern of decrease in the spindle rotation speed is memorized in advance. Program control or the like is applied to reduce the number of rotations depending on the winding time.

The present invention uses such a spindle drive type winder, and gradually decreases the winding width as the yarn diameter of the package increases, and adjusts the traverse speed T (CIrL/sec) to 2≦T≦IL.
It is necessary to wind the throat rubber between 400 and 400 mm. However, ■ indicates the winding speed (m/min). Traverse speed T is 180 (crn/sec)
If it is faster, the traverse speed is too fast, which increases the winding tension on both ends of the package and tends to cause thread accumulation, and the impact force at the time of folding is too large, causing large distortion during winding. V given. When the traverse speed T is less than TiT (cm/sec), the deviation between the previously wound yarn and the next wound yarn due to traverse on the package surface is small, and the yarns are too close to each other.

For this reason, tension fluctuations during unwinding are large, causing problems in higher-order processes. The traverse speed is set to □<T<, -L-1800-
--- It is preferable to control within the range of 300 (cIrL/sec).

By sequentially decreasing the winding width as the winding diameter of the yarn increases, a preferable taper angle can be imparted to the package, and a stable package form can be formed. If a real twist is added to the yarn to be wound to improve unwinding property, extra strain will be added to the yarn, which will later appear as unevenness. You need to wind it up.

Note that the heating zone in the present invention only needs to be a heated space through which the yarn passes, and for example, a tube having a cylindrical shape or a rectangular cross section is used.

In order to perform uniform stretching in such a heating zone,
Flow rate 10-8 ONl/min during heating zone.

A preferred method is to heat the heating zone atmosphere from around the heating zone to 100 to 300°C while introducing heating gas at a temperature of 100 to 300''C.

In addition, when introducing heated gas into the heating zone, if it is introduced from the top of the heating zone so as to be approximately perpendicular to the running direction of the yarn, and then introduced along the five running directions of the yarn, the uniformity is further improved. If a filter is arranged to surround the yarn path and the heated gas is introduced while being rectified through this rectifying filter, the uniformity will be further improved.

Further, when the yarn enters the heating zone after solidification, it is preferable that the yarn is not completely bundled because the heat treatment efficiency is good and the uniformity is also good.

In addition, applying interlacing treatment to the yarn before winding to improve the convergence of the yarn prevents abnormally high strain or stress from being applied to each single yarn during winding. Also, it is preferable because it facilitates stable unwinding in higher-order processes. The degree of entanglement is achieved by providing agitation that slightly disturbs the parallelism so that the filaments are not completely parallel. Preferably, the number of entanglements on water is 1 to 7 m/m. When it is 70 strands/m or more, when a woven or knitted fabric is produced, the number of remaining entanglements in the gray fabric may be too large, causing irritation and deterioration of quality.

The position where the interlacing process is performed can be arbitrarily selected depending on the purpose, such as in front of the first godet roller, between the first godet roller and the second godet roller, or between the second godet roller and the winder. In particular, it is preferable to install it before the first godet roller or between the first and second godet rollers in terms of operability and uniformity of entanglement.

In order to make the polyester fibers wound around the package more uniform, it is more effective to take into account the tension at the time of winding and the bobbin diameter. That is, since the relaxation of strain after the package is made depends on the tightening force, it is preferable to reduce the tightening force as much as possible. Generally, when tightening a pan cage, the force P is expressed as P = -1'' (T (r): winding tension) at a point r at a distance from the center of the package, but it is preferable to decrease the value of P. Specifically, it is possible to lower the winding tension T(r) or increase the radius of the innermost layer portion.In other words, it is possible to increase the bobbin diameter.

The winding tension T(r) is 0.5 g/d, more preferably 0.5 g/d.
Keep it below 3g/d. The bobbin diameter is preferably 2 inches or more from the viewpoint of production efficiency.

Furthermore, the method for manufacturing the polyester fiber package of the present invention will be explained based on the drawings.

FIG. 1 is a schematic diagram showing an example of the spinning and winding process of the present invention.

The polyester yarn Y melt-spun from the spinneret 1 is cooled and homogenized by the cooling device 2, and then introduced into the heating zone B. The polyester yarn Y heated and drawn in the heating zone is applied with a predetermined amount of oil by an oil supply device 4, and is taken off by a take-off roller 6.7 at a take-up speed of 4000 m/min or more while being entangled with an interlace nozzle 5.

The yarn coming out of the second godet roller 7 passes through a fixed traversing fulcrum 9 and a traverse guide 10 that performs reciprocating motion, and is wound into a pirn-shaped package 11 by a winding device 12.
It is wound up at a speed of 000 m/min or more.

The winding device 12 is of a spindle drive type and has a drive motor 16.
It is independently driven by. The drive motor is controlled via a tension detector 8 that detects the winding tension and a controller 14. The drive motor is controlled by a control panel 14 consisting of a power controller 15 and a tension setting device 16 so that the winding tension is constant, and the winding speed is always controlled to be constant. The rotating package 11 is being rotated without contacting anything.

Moreover, FIG. 2 is a longitudinal sectional view of a heating cylinder showing an example of a heating zone in the present invention. The cooled and solidified polyester yarn Y runs into the heating cylinder 17 without contacting the heating cylinder and is heated. A rectifying filter 19 is provided at the top of the heating cylinder 17,
A heated gas supply unit 20 is provided to surround the filter, and the heated gas is supplied to the heated gas introduction pipe 2 through the filter 19.
Install from 1.

Regarding the method of introducing the heated gas, although a filter type is illustrated, the method is not limited to this.

〔Effect of the invention〕

The polyester fiber of the present invention has a yield point stress of 1.7 to 2.
．． At 8 g/d, ΔT during the variation of the stretch tension value measured in the fiber axis direction at 4% stretch was 0.13 g/d.
d or less, the amorphous orientation is appropriately controlled, and the occurrence of fuzz, sink spots, and dye spots during high-speed weaving is prevented.
The uniformity of the grain in the grained fabric can be obtained.

For polyester fibers, the taper angle is within 25° and the thread length per unit length in the direction of the bobbin axis of the package is 3 to 40.
%, the occurrence of strain distribution in the package is prevented, and fluctuations in unwinding tension and generation of fluff during unwinding are also prevented.

Further, according to the method for producing polyester fiber of the present invention, the polyester yarn discharged from the spinneret is once cooled to below the glass transition temperature, then introduced into the heating zone again, heated in the heating zone, drawn, and then wound. Using a spindle drive type winder with a speed of 4000 m/min or more, the package being wound is kept at a traverse speed of TCrr without contact with other objects.
Since the yarn is wound by traversing V/2400≦T≦V/180 with a slow wrapper whose L/sec satisfies the following formula, the amorphous orientation is uniformly controlled and the wrinkle performance in high twist applications is improved. , and the occurrence of internal distortion of the package is prevented.

In addition, the method of measuring physical property values in the present invention is as follows.

(1) Yield Point Stress Using a Tensilon tensile tester manufactured by Toyo Baldwin Co., Ltd., a strength and elongation curve was drawn under the conditions of a sample length of 2 oomm and a tensile speed of 100 mm/min. A model chart is shown in Figure 3. From the chart, we define the strong point Y of the intersection C between the tangent A passing through the origin and the tangent B of the straight line after the curve yields, and Y
The value obtained by dividing d by the denier d of the multifilament is the yield point stress.

(2) 4% Stretch A model diagram of a measuring device for measuring ΔTΔT during fluctuation of tension value is shown in FIG.

The thread 26 to be tested unwound from the package 22 passes through the guide 24 and is adjusted to a primary tension of 0.1 g by the tension adjustment device 25.
/d, and the dancer at a constant speed of 226° to 28°.
After adjusting the tension to a constant tension by applying a load of 0.2 g/d using the roller 27 and the load 27', the roller 60 is stretched by 4% between the rollers 28 and 30 arranged at an interval of 1501++ m, and the surface relationship of the roller 60 is 8.0 m7. Run continuously in minutes. At this point, the tension fluctuation in the extended portion is detected by a pickup 29 and recorded at a chart speed of 60 mm/min. In the figure, f represents a frictionless roller, S represents a separate roller, and 31 represents a winder.

FIG. 5 shows an example of a chart obtained by measurement using the apparatus shown in FIG. Select 5 of the largest tension fluctuations among the 15 chart lengths of an arbitrary part ΔT1. Δ
T2...ΔT.

(3) Method for measuring the number of entanglements on water A sample of approximately 1 m length is placed horizontally on a stationary water surface without applying substantial tension. At this time, the spread part of the yarn opens due to water, but if there is a part where substantially all the single yarns are bundled and do not open, count this number and calculate the number of bundled pieces per part of length. , those in which substantially all of the filaments are not bundled and some of the filaments are spread out are not counted.

(4) Uniformity (Worcester's mottling) Yarn speed 25
The thickness unevenness in the direction of the fiber axis was measured for 7 minutes at normal speed, range ±12.5%, and Chiroth speed 5, and the U-chi value was determined.

Examples of the present invention will be shown below.

〔Example〕

<Example-1> Polyethylene terephthalate fibers were obtained by different manufacturing methods shown below.

<Production method 1> Polyethylene terephthalate was melted at 290°C and discharged from a nozzle with a 36-hole diameter of 0.2 mm. Spinning speed 5000? ? +, /min, 6oooom/min binding 75D-
A yarn of 36F was obtained. The winding device shown in FIG. 1 was used. The traverse reciprocating speed is 10 crIL/sec.
The taper angle was 20°. These samples also /161゜2
shall be.

<Manufacturing method 2> Polyethylene terephthalate was melted at 290°C, discharged at a rate of 29.2 g per minute from a mouth with a hole diameter of 0.2 mrnφ36, and heated to 85°C after applying an oil agent.
A pair of flannelettes were drawn at a speed of 1000 m and 7 minutes using a pair of Nelson-type heated rollers, then heated to 160°C, stretched 3.5 times using non-type heated rollers, and then stretched in the same manner as in manufacturing method 1. Traverse reciprocating speed 10c1rL/sec, speed W 3500 m 7 minutes with spindle drive type winder,
It was wound with a taper angle of 20°. Let this sample be /163.

<Manufacturing method 3> Polyethylene terephthalate was melted at 290°C and discharged from a nozzle with 36 holes and a hole diameter of 0.2 mmφ. Inner diameter 15m1φ with cooled and solidified filament installed 2m below the cap.
It was introduced into a heating cylinder having a length of 1 rn as shown in FIG.

The heating cylinder is electrically heated from around the cylinder, and its set temperature is 20
The temperature was set to 0°C. Also, inside the heating cylinder, there is a temperature of 200'C, 25N.
! ! /min of heated gas was introduced through a sintered metal filter with an opening of 20μ.

The yarn that had passed through the heating zone in this manner was taken off by changing the take-up speed, and samples of /164 to /168 were obtained. Note that the discharge amount was changed according to the take-up speed so that the total denier was 75D. The winding device used was the same as that used in manufacturing method 1, with a traverse reciprocating speed of 10 c1n/sec and a taper angle of 20°.

Table 1 shows the physical property values of samples 1 to 8 obtained by the above-mentioned manufacturing methods 1 to 3. Table 1 also shows the results of high-speed weaving when embossed fabrics were produced using these fibers.

(Margin below this page) As is clear from Shishi-1, the yarn manufactured by the manufacturing method 3 of the present invention and taken at a take-up speed of 4000 m/min or more has a yield point stress of 17 to 2.
．． 8 g/d, and the woven fabric performance was also good, with no sink spots occurring even during high-speed weaving.

<Example-2> Polyethylene terephthalate was melted at 290°C and
．． Spinning from 2 mmφ36 nozzles, take-up speed 130
It was pulled at a speed of 0 m/min.

The undrawn yarn thus obtained was stretched at various draw ratios to obtain yarn having a yield point stress of 1.7 to 2.8 g/d.

The U% values of these yarns were all distributed between 0.92 and 1.35, and the uniformity was poor. Furthermore, when such threads were dyed into fabrics, dyeing spots occurred frequently.

<Example 3> Material A6.7 of Example 1 was wound under the same conditions as Example 1, with the traverse reciprocating speed changed as shown in Table 2. The stretch tension ΔT of the wound yarn is also shown in Table 2.

<Table 2> As is clear from Table 2, only /i69-11 and A15-17, which satisfy the traverse reciprocating speed within the range of the present invention, have homogeneous and good packages.

<Example-4> Except for the winding machine, the / of Example-1 was prepared in the same manner as in Example-1.
Supply yarn of I66.7. The winder was a TW-601 cheese winder manufactured by Toshi Engineering Co., Ltd., and the traverse speed was 850 reciprocations/min.

The stretch tension ΔT of the obtained package was 0.24 at a winding speed of 4,000 m/min, and ΔT at a winding speed of 5,000 m/min.
It can be understood that the cheese winder is not preferable because it is 0.27 per minute.

<Example-5> Example-1 except that the heated gas flow rate introduced into the heating zone for the sample of Example-IA7 was changed as shown in Table-3.
A package of 75 denier and 36 filaments was obtained under the same conditions as in Example 1. The U% values of the obtained yarns are also shown in Table 3.

<Table-3> Raku flow rate Uchi value 1980.87 2Q ICI 0.52 21 25 0.43 22 40 0.51 23 80 0.68 24 90 0.94 As is clear from Table-3, the flow rate is 10~ A20 to A23 satisfying 5 oNr/min are preferable because they have a small U% value and good uniformity.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of the spinning and winding process in the present invention, Fig. 2 is a longitudinal sectional view of a heating cylinder showing an example of the heating zone of the invention, and Fig. 3 is an S-8 showing the yield point stress. A model diagram of the curve, Figure 4 is a model diagram of a measuring device for measuring ΔT during fluctuations in stretch tension, and Figure 5 is a model diagram of a measuring device used to calculate ΔT. Shows the chart. 6... Heating cylinder, 10... Winding device, 16... Package. Agent: Patent Attorney Shin Ogawa − Patent Attorney Ken Noguchi Patent Attorney Kazuhiko Saishita Figure 2 f Medium

Claims (1)

[Claims] 1. When the yield point stress is 1.7 to 2.8 g/d, and the stretch tension value measured in the fiber axis direction at 4% stretch is changing, and ΔT is 0.13 g/d or less. , and a package made of polyester fibers that are not substantially twisted, the unit length of the package in the bobbin axis direction is 1 cIrL) The yarn length of this package is 3 to 40771 mm, and the package end face is within 25 degrees. A polyester fiber package having a tapered angle of . 2. After the polyester yarn discharged from the spinneret is once cooled to below the glass transition temperature, it is introduced into the heating zone again, heated and stretched, and then wound using a spindle drive type winding machine with a winding speed of 4000 m/7 minutes or more. Traverse speed TcIrL/ of the package being picked up without contacting other items.
The yarn is traversed with a slow laparse whose seconds satisfy the following formula, and the yield point stress is 1.7 to 2.8 g/d.During the fluctuation of the stretch tension value measured in the fiber axis direction at 4% stretch, ΔT is 0. .13g/d or less yarn length per unit length (1cIrL) in the bobbin axis direction: 3~
A method for producing a polyester fiber package, which comprises winding a package having a length of 40 m and substantially no real twist. V/2400≦T≦V/180 (In the formula, V is the winding speed m7 minutes.)