JP3259568B2 - Synthetic fiber melt spinning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a melt spinning method for efficiently cooling a spun yarn in melt spinning a synthetic fiber.

[0002]

2. Description of the Related Art In the melt spinning of synthetic fibers, as is well known, it is necessary to cool the temperature of a yarn spun from a die to a glass transition point in order to stabilize yarn production and facilitate operation. However, in recent years, for example, the winding speed of 6000 m / min or more has been increased, and the fineness of single yarn fineness of 60 denier or more as an industrial material has been remarkably increased. Things are required.

[0003] As a conventional yarn cooling device in such a situation, for example, a cooling device described in Japanese Patent Application Laid-Open No. 41-7892 is used in a direction perpendicular to the running direction of the yarn. The mainstream is to blow cooling air, but with such a cooling device, the heat exchange between the spun yarn and the cooling air is insufficient, so that insufficient cooling of the yarn or uneven cooling occurs, and the spun yarn Unevenness of fineness due to fusion and solidification point fluctuation,
Yarn breakage and the like frequently occur, and there is a defect that spinning operability is deteriorated and yarn quality is reduced.

[0004] As a method of solving this problem, for example, there is a method of increasing the length of a cooling pipe such as a cooling chimney or increasing the amount of cooling air. Among the cooling methods, the method of adjusting the length of the cooling pipe is designed in consideration of the take-up speed of the spun yarn and the temperature of the cooling air in designing the length of the spun yarn. It did not accurately reflect the yarn physical properties such as fineness, specific heat, and density, and the yarn temperature at the inlet and outlet of the cooling pipe. Therefore, the obtained cooling device does not provide the desired cooling performance, or may be an over-spec device in some cases and cannot efficiently cool the yarn.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and relates to a method for melt-spinning a synthetic fiber. Yarn properties such as fineness, specific heat and density of the spun yarn,
By reflecting the yarn temperature at the inlet and outlet of the cooling line , the appropriate line length is adjusted so that the yarn can be cooled efficiently.
It is an object of the present invention to provide a method for melt-spinning synthetic fibers to be adjusted .

[0006]

In order to achieve the above-mentioned object, a method for melt-spinning synthetic fibers according to the present invention comprises the steps of: producing a synthetic fiber by a melt-spinning cooling device provided at a predetermined position below a melt spinneret ; a melt spinning method <br/> cooling to synthetic fibers, and ejector portion having an inlet for pre-Symbol yarn which is spun from the melt spinneret and inlet of cooling air, is connected to the lower portion of the ejector unit A cooling pipe extending in a direction in which the yarn is taken off, and an outlet for the yarn and a cooling air outlet connected to a lower portion of the cooling pipe, and a cooling air supplied to the ejector unit. The cooling of the melt spinning cooling device, comprising: an exhaust unit that exhausts the yarn in a direction in which the yarn is separated.
The pipeline length (L) of the pipeline satisfies the following equations (1) and (2).
Melt spinning method of synthetic fiber characterized by adjusting
Law.

[0007]

(Equation 5)

[0008]

(Equation 6) However, the signs in Equations 5 and 6 are as follows:
And

L: Pipe length (mm) C _p : Polymer specific heat (cal / ° C. · g) ρ: Polymer density (g / mm ³ ) d: Single fiber fineness (denier) at the time of entering a cooling device V _S : Cooling yarn speed during device rush (mm / s) V _a: the cooling air velocity (mm / s) T _H: cooling air temperature (℃) T _IM: cooling device rush before the yarn temperature (℃) T _OUT: cooler outlet yarn temperature at (℃) T _g: If it is desired to further rapid cooling below the glass transition point (℃) is below the melt spinneret
Apparatus for melt-spinning synthetic fibers provided at one predetermined position
This is a synthetic fiber melt spinning method in which the yarn is cooled by
The inlet and cooling of the yarn spun from the melt spinneret
An ejector section having a wind inlet, and the ejector
Connected to the lower part of the section and extending in the take-off direction of the yarn.
And a lower portion of the cooling line, and
It has a mouth and an outlet for cooling air, and supplies it to the ejector section.
Exhausting the cooled cooling air in a direction to separate it from the yarn.
And a cooling part of the cooling line of the melt spinning cooling device comprising
Adjust the pipe length (L) so as to satisfy Equations 7 and 8 below.
And adjust the ejector to 10-40
g / min in the range of synthetic fibers
Melt spinning method.

[0010]

(Equation 7)

[0011]

(Equation 8) However, the signs in Equations 7 and 8 are as follows:
And

L: Pipe length (mm) C _p : Specific heat of polymer (cal / ° C. · g) ρ: Polymer density (g / mm ³ ) d: Single fiber fineness (denier) at the time of entering a cooling device V _S : Cooling yarn speed during device rush (mm / s) V _a: the cooling air velocity (mm / s) T _H: cooling air temperature (℃) T _iN: cooling device rush before the yarn temperature (℃) T _OUT: cooler outlet Temperature (° C.) T _g : glass transition point (° C.) Further , a forced exhaust device such as an exhaust fan or a blower is connected to the outlet of the cooling air of the exhaust unit to forcibly exhaust the cooling air.
It is more preferable to care .

The synthetic fiber to which the cooling device of the present invention can be applied is not particularly limited as long as it can be melt-spun, and for example, various fibers such as polyester, polyamide and polyolefin are possible.

[0014]

According to the present invention, there is provided a method for melt-spinning a synthetic fiber, comprising: an ejector section having an inlet for a yarn and an inlet for cooling air; a cooling pipe extending in a yarn take-off direction; A cooling air supplied to the ejector section along the axial direction of the cooling pipe, since the cooling section has an air outlet and an exhaust section for exhausting the cooling air in a direction separating the yarn from the yarn. Since heat is sufficiently removed from the yarn while flowing down with the warp yarn, and then exhausted from the exhaust unit, heat exchange of the yarn is efficiently promoted.

Furthermore, the number 5 and equation (6) is determined type of pipe length of the cooling pipe (L mm), the fineness of the spun yarn, the specific heat,
The yarn properties such as density, yarn take-off speed, cooling air speed and temperature, yarn temperature and the like are taken into consideration. Thereby, even if parameters such as cooling air velocity, cooling air temperature, polymer specific heat, density, yarn take-up speed, fineness, yarn temperature, etc. are different, the cooling device outlet temperature of the spun yarn can be widened to a desired value. In addition to being able to control accurately and accurately, it is possible to obtain an optimum cooling pipe length suitable for various cooling conditions.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the melt spinning cooling of the synthetic fiber according to the present invention will be described.
One embodiment of the method will be described with reference to the drawings.

FIG. 1 is a schematic side view of a spinning apparatus using the method for melt-spinning and cooling synthetic fibers according to the present invention. In the figure, reference numeral 1 denotes a spinneret for spinning out molten synthetic resin as a large number of yarns 2, and is connected to an extruder (not shown) provided above the spinneret.

Reference numeral 10 denotes a synthetic fiber melt spinning cooling device according to the present invention, which comprises an inlet 6a for the yarn 2 and an inlet 6b for cooling air.
And a cooling pipe 7 having a pipe length of L (mm), and an exhaust section 8 having an outlet 8a of the yarn 2 and an outlet 8b of cooling air. Is fixed by a bracket (not shown) at a lower position at a relatively short distance H (mm) from.

In the upper part 3 of the ejector 6, the cooling device 10 is sufficient as a cooling capacity, but more preferably, mist cooling for spraying a liquid mist to the inlet 6 a of the ejector 6 in order to enhance the cooling capacity. The apparatus is connected to an ultrasonic humidifier 5 via a mist introduction pipe 4. The liquid mist may be not only water but also an oil agent for fibers. If the particle size of the liquid mist is too large, irregularities and fineness irregularities are likely to be generated on the yarn surface due to the collision of the mist. Conversely, if the size is extremely small, the cooling effect can hardly be expected, so the particle size of about 5 to 15 μm Are preferred. The liquid mist spray amount is 10 to 40 g / min.
The humidification amount is preferably

On the other hand, 9 below the exhaust portion 8 is
This is a godet roller for drawing the yarn 2 cooled to an appropriate temperature at a predetermined speed and stretching it to a desired fineness, and is driven by a motor (not shown).

The ejector section 6, the cooling pipe 7 and the exhaust section 8 of the cooling device 10 are all made of a thin steel plate, and are integrally formed by welding. Each of these members has a cylindrical cross section in a direction perpendicular to the running direction of the yarn, but may have a rectangular shape. The cooling air inlet 6b of the ejector unit 6 is connected to a cold air generator (not shown) such as a compressor with a cooler, for example.
A cool air having a flow rate Q1 (m ³ / min) and a cooling air temperature T _H (° C.) can be supplied. In addition, it is preferable that a forced exhaust device such as an exhaust fan or a blower is connected to the outlet 8b of the cooling air of the exhaust unit 8 so as to forcibly exhaust the cooling air having a flow rate Q2 slightly higher than the flow rate Q1. .
Further, a cylindrical filter 8c made of a perforated plate is fixed inside the exhaust portion 8 so that the cooling air can be exhausted uniformly from around the yarn 2.

The feature of this embodiment is that the length L of the cooling line 7 is within the range specified by the above equation ( 5 ). Equation ( 5 ) is used to determine the pipe length L, which is the cooling capacity of the cooling pipe 7, and the important factors such as the take-up speed of the spun yarn 2 (the peripheral speed of the god roller 9) and the wind speed of the cooling air. , Temperature, yarn properties such as fineness of spun yarn, specific heat, density, and other factors of yarn temperature at the entrance and exit of the cooling pipe are empirical formulas. It was found.

The inventor conducted the following experiment to find this empirical formula.

First, in order to check the cooling characteristics of the cooling device 10 shown in FIG. 1, as shown in FIG. 2, a multifilament yarn 12 (150 denier, 48 filaments) made of polyester is previously tied on the hot plate 14. Then, the yarn was heated to 200 ° C., and thereafter, the yarn was cooled by passing through the cooling device 15 at a yarn speed of 600 m / min. The cooling air temperature T at the cooling device inlet 15a
_H at the cooling device outlet 15b and the yarn temperature T _IN at the cooling device outlet 15b.
_OUT was measured, and the heat transfer coefficient h (cal / mm ² · sec · ° C) indicating how much heat was able to be taken from the running yarn 12 in a unit time was obtained from the obtained data. 9 expression of C. R. It was calculated from the Jones equation.

[0025]

(Equation 9) h: heat transfer coefficient, (cal / mm ² · sec · ° C.), _TH : cooling air temperature (° C.) T _IN : yarn temperature before entering the cooling device (° C.) T _OUT : yarn temperature at the cooling device outlet ( ° C) ρ: Polymer density (g / mm ³ ) r: Radius of yarn (mm) C _p : Specific heat of polymer (cal / ° C · g) t: Time required for yarn to pass through cooling device (sec) Next, cooling air When the speed V _A (mm / s) is changed to various values and the relationship with the heat transfer coefficient h is obtained, the relationship shown in FIG. 3 is obtained.
Thus, the approximation equation h in Figure 3, the following Equation 10 Equation

[0026]

H = 0.634 × 10 ⁻⁵ V _A ^0.291

Next, the heat transfer coefficient h obtained by the equation ( 10 )
Is substituted for h in the equation ( 9), the following equation ( 11) is obtained.

[0028]

[Equation 11] Here, for convenience,

[0029]

(Equation 12) (Equation 6 above).

The yarn 2 spun from the synthetic fiber melt spinneret 1 is cooled by a melt spinning cooling device 10 provided below the melt spinneret. Above, there is no need to cool to below the glass transition temperature T _g (° C.). Therefore, in the above equation ( 11) , the yarn temperature T _OUT at the outlet of the cooling device is changed to the glass transition point T _g.
Equation 13 below obtained by substituting

[0031]

(Equation 13) Is the upper limit of the cooling pipe path length L (mm), the number 11
The expression can be said to be the lower limit of the cooling pipe length L.

Therefore, the above equations ( 5) and ( 6 ) were obtained from the above equations ( 11) and ( 13 ).

Next, an experiment similar to the above was conducted using the mist cooling device 3 together. That is, assuming that the liquid mist is sprayed from the ultrasonic humidifier 5 at a flow rate of 33 g / min and other conditions are the same as those in the above experiment, the coefficient 15 of the equation 6 is 1
The cooling pipe length L is 1.5 to 0.75 to 0.8 times shorter than the case where the ultrasonic humidifier is not provided.

Embodiments 1 and 2 In order to see the effect of only the cooling device 10 shown in FIG. 1, the ultrasonic humidifier 5 was stopped, and the polyester multifilament yarn 2 (150 denier, 48 The filament (filament) is heated to 200 ° C. by running on a hot plate (not shown) provided above the cooling device 10 (the yarn temperature T _IN before entering the cooling device is about 170 ° C.). speed V _s is 600m / min (1000
(0 mm / sec) and passed through the cooling device 10 for cooling. In this case, the yarn temperature T to be obtained at the outlet 7a of the cooling device
_{As OUT} , two points of 115 ° C and 120 ° C are selected, and the corresponding cooling air at a temperature of 26 ° C is 0.45m.
^It was supplied at ³ / min, 0.55 m ³ / min (Q1). Further, the inlet 6a of the cooling pipe 7, the yarn temperature T _IN at the outlet 7a, and measured the T _OUT, from the obtained data the heat transfer coefficient h of the equation (9) C. R. Calculated from the Jones equation, the pipe length L of the cooling device is calculated from the above equation ( 11 ).
90 mm was obtained.

The evaluation method of each characteristic value is as follows.

<Yarn Temperatures T _IN and T _OUT > Using a TH-BM type non-contact type thermometer for measuring running yarn temperature, manufactured by Tokyo Seiko Co., Ltd., at the inlet 6 a and the outlet 7 a of the cooling pipe 7, respectively. The yarn temperatures T _IN and T _OUT were measured.

[0037] <cooling air velocity V _A, the cooling air temperature T _H> by Nippon Chemical Industrial Co., Ltd. of Anemo master, the cooling air velocity V _A at the outlet 7a of the cooling pipe 7, the cooling air temperature T _H
Was measured. The polymer specific heat C _p , polymer density ρ
It is known since a physical property value, and fineness d during cooling device rush, yarn velocity V _S of the cooling device inrush, the spinning of the spinneret 1, and the take-up speed of the godet roller 9 Was obtained in advance by calculation from the relationship.

Embodiments 3 and 4 Next, in order to see the effect when the mist cooling device 3 is used in combination, cooling was performed while spraying liquid mist from the ultrasonic humidifier 5 at a flow rate of 33 g / min. Other cooling conditions were the same as in Example 1.

Table 1 below summarizes the results of Examples 1 to 4.

[0040]

[Table 1]

As shown in Table 1, the yarn temperature T _{OUT of the} yarn 2 to be obtained at the outlet 7a of the cooling device of the present invention is 115, 1
According to the above equation ( 11) of the present invention, the temperature was 20 ° C., but as shown in Table 1, it becomes 121.4 ° C. and 116.2 ° C., and there is no significant difference between the equation ( 11) of the present invention and the measured value. That is, if the spinning conditions such as the fineness, specific heat, density, take-off speed, cooling air temperature, etc. of the spun yarn are known in advance, a yarn with a desired cooling temperature can be obtained, and an appropriate pipeline with excellent cooling efficiency. It can be seen that a long cooling device is easily obtained.

[0042]

As described above, according to the present invention, the melt spinning process of the synthetic fiber according to the present invention, below the spinneret, take-up speed of the spun yarn, not cooling air temperature alone, the fineness of the spun yarn, specific heat,
A proper cooling pipe length (L) without waste reflecting factors such as the physical properties of the spun yarn such as the density and the yarn temperature at the inlet and outlet of the cooling pipe is adjusted . In other words, even when a plurality of spinning conditions such as a yarn type and a take-up speed of the spun yarn are different, from these data, the cooling device outlet temperature of the spun yarn can be controlled over a wide range, and various cooling conditions can be controlled. it is possible to obtain a cooling pipe length of the best adapted to.

[Brief description of the drawings]

FIG. 1 is a schematic side view of one embodiment of a melt spinning cooling apparatus for synthetic fibers according to the present invention.

FIG. 2 is a schematic side view of the experimental apparatus of the present invention.

FIG. 3 is a diagram showing a relationship between a cooling air velocity V _A and a heat transfer coefficient h in the experimental device of the present invention.

[Explanation of symbols]

 1: spinneret 2: yarn 3: mist cooling device 4: mist introduction tube 5: ultrasonic humidifier 6: ejector unit 7: cooling line 8: exhaust unit 9: god roller 10: cooling device 11: bobbin 12: multi Filament 13: Roller 14: Hot plate 15: Cooling device 16: Yarn thermometer 17: Suction gun L: Pipe length

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-174614 (JP, A) JP-A-3-137209 (JP, A) JP-A 55-54370 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) D01D 5 / 092,5 / 096

Claims (3)

(57) [Claims] A yarn is cooled by a melt spinning cooling device for synthetic fibers provided at a predetermined position below a melt spinneret.
A melt spinning method of the synthetic fibers to the ejector portion having the previous SL inlet of the yarn is spun from the melt spinneret and inlet of cooling air, is connected to the lower portion of the ejector portion, the yarn A cooling pipe extending in a take-off direction, connected to a lower part of the cooling pipe, having an outlet for the yarn and an outlet for cooling air, and the cooling air supplied to the ejector unit is provided with the yarn. A pipe for the cooling pipe of the melt spinning cooling apparatus, comprising: an exhaust unit for exhausting gas in a separating direction.
The length (L) is adjusted so as to satisfy the following equations (1) and (2).
Melt spinning a synthetic fiber. (Equation 1) (Equation 2) However, the signs in Equations 1 and 2 are as follows:
And L: Pipe length (mm) C _p : Polymer specific heat (cal / ° C. · g) ρ: Polymer density (g / mm ³ ) d: Single yarn fineness when entering a cooling device (denier) V _S : When entering a cooling device yarn speed of (mm / s) V _a: the cooling air velocity (mm / s) T _H: cooling air temperature (℃) T _in: cooling device rush before the yarn temperature (℃) T _OUT: yarn in the cooling device outlet Temperature (° C) T _g : Glass transition point (° C) 2. A method according to claim 1 , wherein said predetermined position is provided below said melt spinneret.
The yarn is cooled by the melt spinning cooling device for the synthesized fiber
Melt spinning method of the synthetic fiber, wherein the inlet of the yarn spun from the melt spinneret and the cooling air
An ejector section having an inlet;
Cooling pipe connected to the lower part and extending in the direction in which the yarn is taken off
A passage, which is connected to a lower portion of the cooling conduit and has an outlet for the yarn.
Having an outlet for cooling air and being supplied to the ejector section.
Exhaust unit that exhausts the cooled air in a direction that separates it from the yarn.
The length (L) of the cooling pipe of the melt spinning cooling apparatus comprising : is adjusted so as to satisfy the following equations ( 3 ) and ( 4 ) .
And the liquid mist in the ejector section is 10 to 40 g /
spraying synthetic fibers within the range of min
Melt spinning method. (Equation 3) (Equation 4) However, the signs in Equations 3 and 4 are as follows:
And L: Pipe length (mm) C _p : Polymer specific heat (cal / ° C. · g) ρ: Polymer density (g / mm ³ ) d: Single yarn fineness when entering a cooling device (denier) V _S : When entering a cooling device yarn speed of (mm / s) V _a: the cooling air velocity (mm / s) T _H: cooling air temperature (℃) T _IM: cooling device rush before the yarn temperature (℃) T _OUT: yarn in the cooling device outlet Temperature (° C) T _g : Glass transition point (° C) 3. A melt spinning process for synthetic fibers according to claim 1 or 2, melt spinning method of synthetic fibers, characterized by strong Seihai care cooling wind.