KR20010027332A - Multifilament Quenching Apparatus - Google Patents

Abstract

PURPOSE: A cooling apparatus capable of uniformly cooling melt spinning multifilament yarns by natural cooling without forced cooling is provided which produces yarns at low cost without a special cooling wind supplying apparatus. CONSTITUTION: In an apparatus for cooling melt spinning multifilament yarn, the apparatus comprises at least one porous cylinder type spin tube (21) formed by air inlet holes having a diameter of 1 to 5mm on the wall and a windshield plate (22) for preventing an eddy, which is disposed at regular intervals at the outside of the spin tube.

Description

Multifilament Quenching Apparatus}

The present invention relates to the improvement of a cooling device for the purpose of uniform solidification during multifilament spinning.

In general, synthetic fiber melt spinning is applied by heating a resin chip to melt it, and then extruded the melted resin into a fibrous multifilament under high pressure through a spinneret and forcibly blowing a cold cooling air into the formed multifilament. The process includes stretching and winding the monofilaments to ensure uniform cooling. This maintains spin stability during the process and uniformity of the final wound yarn. At this time, however, it is very difficult not only to draw the external air and blow the cooling wind to have a uniform velocity distribution on the fiber bundle, but also to keep the temperature and humidity uniform regardless of the season.

At this time, if the multifilament exiting the spinneret is not uniformly cooled, the solidification point is different for each filament, which causes a difference in thickness between the monofilaments. In this state, when stretching through the Godet roller, there is a difference in elongation and natural draw ratio between the thin filament and the coarse filament, so that the single yarn occurs in the low elongation monofilament, and this is the single yarn in the process or fluff).

In order to solve this problem, it is common to install a cooling device on the spinning process to uniformly cool the monofilaments through forced cooling. Cooling in the spinning process may be said to uniformly cool and solidify the polymer melt discharged through the spinneret using air or water. This improves the fiber uniformity by reducing the cooling deviation between monofilaments, increases the melt viscosity by cooling during microfiber or high draft spinning, and prevents trimming directly under the spinneret. This results in uniform orientation and crystallization of each filament resulting in a yarn having uniform physical properties.

1 shows an example of a spinning process in which a conventional general cooling device is installed, and air is usually used as a refrigerant. The molten polymer extruded through the spinneret 10 of the spinning device is cooled by the air discharged from the cooling device 20. Reference numeral 30 denotes an oil ring guide. Such a cooling device requires a device that draws in external air to a desired temperature and humidity, and further needs a honeycomb device that can supply it uniformly. Such a cooling device shows an excellent uniformity during the sacrifice of a general company, but because of the cooling wind blows from only one side, there is a problem that the cooling speed difference with the other side occurs in the case of multifilament. For this, both side quenching and cylindrical quenching have been proposed, but problems of workability and cost reduction are still not solved.

As a technique of a patent document in the art, Japanese Patent Application No. 56-96908 proposes a device that can achieve uniform cooling by attaching a simple facility without a separate cooling air supply device in order to reduce the cost of the cooling device. According to this technique, the fiber bundle leaving the spinneret is cooled by outside air sucked along the airflow generated by the fiber running through a spinneret with stops installed on both sides, four sides or ovals.

However, this method saves the manufacturing cost and equipment cost of the cooling wind, but it is impossible to apply it in the case of Taesomdosa and High Multi-Seamsa, and it is impossible to apply it. impossible. Therefore, this equipment has a problem that is limited to some varieties. In addition, in order to improve the cooling efficiency, the rectifying plate must be installed in four sides or a cylindrical shape, which leads to a problem of poor workability.

Therefore, the present invention is not limited to the variety in view of the above problems of the prior art as described above can be cooled with excellent cooling efficiency, excellent workability, to provide a melt spinning value that can reduce the cost of using the cooling wind Let it be technical problem.

The reason for cooling using the cooling wind during melt spinning can be seen from the thermal equilibrium after spinneret discharge. When the polymer melt exits the spinneret and passes through the air, the polymer melt has heat loss due to convection and radiation (see Equation 1).

Where R is the filament radius, h is the heat transfer coefficient, T is the filament temperature, T _air is the cooling wind temperature, Δt is the elapsed time, σ is the Stefan-Boltzmann constant, ε is the emission coefficient, ρ is the filament Density, C _p, is the filament heat capacity.

In Equation 1, the first term on the left side is heat loss due to convection, the second term is heat loss by radiation, and the right side is total heat loss.

However, if the speed is high enough, such as in the spinning process, the heat loss due to radiation is negligible and eventually most of the heat loss is caused by convection. Therefore, the thermal equilibrium during the spinning process is represented by tropical flow due to the temperature difference between the filament and the air as shown in Equation 2.

In the formula, z is the axis in the direction of anti-radiation, D is the filament diameter, and W is the discharge amount.

In this equation, in addition to the temperature difference between the filament and the air, the discharge amount, heat capacity, etc. also have a big influence, and once the varieties are determined, they are determined so that the heat transfer coefficient (h) can act as a process variable.

According to Kase and Matsuo, the heat transfer coefficient in the spinning process is expressed by Equation 3 [J. Applied Polymer Science, Vol. 11, pp 251-287 (1967).

Where A is the cross-sectional area of the filament.

These experiments show that if the cooling wind speed (V _air ) is always constant in the cooling zone, there is a point where V _air /V=0.125 and the cooling wind temperature (T _air ) is constant based on this point. Could get

Directly below the spinneret: V << V _air and V _air / V> 0.125 The cooling rate of the filament is determined by the cooling wind speed (V _air ).

-Near freezing point: V>> V _air and V _air / V <0.125 By the filament speed V, the filament solidification rate is determined.

According to this result, it appears that the contribution from the cooling wind speed is large because the firing speed is directly below the spinneret. Able to know. Therefore, active cooling by forced exhaust of the cooling wind has the greatest effect directly under the spinneret, and if high _air velocity shortens the area of V _air / V> 0.125, smooth cooling without forced exhaustion will be possible. .

The present invention has been studied a device that can achieve uniform cooling without generating a separate cooling wind and exhaust device in the high-speed melt spinning by using this point, as a result of the installation is very simple and the outside air cooling and humidity maintenance It has been developed a cooling method and apparatus of the natural cooling method unnecessary economical and excellent cooling efficiency.

1 is a view for explaining the principle of cooling in the melt spinning apparatus of a conventional general multifilament yarn.

Figure 2 is a view schematically showing a molten spinning device is installed multifilament yarn cooling apparatus according to an embodiment of the present invention.

Figure 3 is a comparative graph showing the wind speed distribution during the spinning process in the cooling apparatus of the present invention and the prior art cooling apparatus.

4A is a schematic view illustrating a spin guide attached to a cooling apparatus according to another embodiment of the present invention, and FIG. 4B is a view illustrating a state in which the spin guide of FIG. 4A is mounted on the spin tube of FIG. 2.

* Description of the symbols for the main parts of the drawings *

10. Spinneret 20. Cooling System

21.Spin tube 22.Wind plate

23. Spin Guide

Therefore, according to the present invention, in the apparatus for cooling the melt-spun multifilament yarns, at least one porous cylindrical spin tube having an air inlet hole having a diameter of 1 to 5 mm at a predetermined interval on the wall and separated into two in the advancing direction of the multifilament yarns; The outer side of the spin tube is provided with a multi-filament yarn cooling device having a vortex prevention windshield is disposed parallel to the left and right sides at a predetermined interval with the spin tube.

In addition, according to the present invention is designed to be attached to the upper portion of the spin tube, it has a double-wall cylindrical shape having a space therein, the air inlet connected to the external air source is formed on the wall, the bottom has a plurality of air injection holes There is provided a multifilament yarn cooling apparatus, further comprising a spin guide formed therein.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

2 schematically shows a multifilament yarn cooling apparatus 20 according to one embodiment of the present invention installed below the spinneret. The present cooling device 20 includes a porous spin tube 21 and a windbreak plate 22. The spin tube 21 is a cylindrical member in which air inflow holes having a diameter of 1 to 5 mm are formed on the wall at regular intervals in the advancing direction of the multifilament yarn, and when the filament travels therein during the spinning, air flow is generated therein. To allow the outside atmosphere to flow into the interior evenly. The incoming air cools down the molten filament and moves downward, forming an air flow therewith, and new air continues to flow in place to continue cooling the filament. Spin tube 21 is preferably designed to be separated into two front and back for workability when hanging. In other words, after passing the bundle of filament to the part that is installed on the makeup plate in advance, simply close the front as if the lid is closed. In the illustrated example, the cooling device is composed of a spin tube of a dual structure, but is not limited thereto, and may be configured in an appropriate number depending on the type of the radiator, particularly the number of spinnerets.

In the present cooling device, a vortex preventing windbreak plate 22 is installed on the outside of the spin tube 21 at a predetermined interval and parallel to the left and right sides thereof.

Figure 3 shows the wind speed distribution measured on the outer wall surface of the tube in the longitudinal direction of the tube when spinning using the spin tube according to the present invention and in the vicinity of the honeycomb wall and the filament when using a general cooling device (Honeycomb, FIG. 1). Graph showing wind speed distribution. As can be seen from the graph, when the spin tube is used, the wind speed of the portion directly below the spinneret is not very low, and the honeycomb part shows high wind speed during forced cooling, but when the spin tube is used, the wind speed drops a lot when near the filament. You can see that there is no big difference.

In order to examine the role of the spin tube more precisely, forced cooling by honeycomb cooling wind, natural cooling without cooling wind, and cooling by spin tube were compared for the same varieties, and the results are shown in Table 1. The results show that the tension acting on the filament is "spin tube Natural cooling <forced cooling> showed lower tension when using natural cooling and spin tube. The lower tension means less air resistance, which is due to late solidification, so cooling effect when using spin tube is lower than forced cooling. You can see that it falls.

However, the uniformity (U) and the cross-sectional distribution of yarns are not good compared to forced cooling, but they are relatively good, which means that the spin tube acts as a rectifier to help intake air uniformly in all directions. Able to know. Therefore, the role of the spin tube is not to improve the cooling effect, it can be seen that the role of rectifying the air so that the cooling is uniformly made in the entire filament.

On the other hand, in the case of low-speed spinning and high multi yarns, the amount of airflow sucked is small so that it does not sufficiently cool all the filaments uniformly. Therefore, it is necessary to increase the amount of cooling air supplied to the yarn. The spin guide 23 shown in Figs. 4A and 4B is a forced cooling air supply means attached to the present cooling device for this purpose.

The spin guide 23 is designed to be attached to the upper portion of the spin tube 21, and has a double-wall cylindrical shape having a space therein, and an air inlet 23a connected to an external air source is formed on the wall, A plurality of air injection holes 23b are formed.

The air introduced into the inside of the spin guide 23 through the air inlet 23a exits the air injection hole 23b and follows the spin tube to meet the filament bundle to uniformly cool and then exit the tube together with the filament. At this time, if the wind speed is high, the filament is broken or uneven due to turbulence, so it should be well controlled.

In the present invention, when the spin guide 23 is applied, the spinning speed shows a good effect even at 2000 m / min, but when the spin guide 23 is not applied, the spinning speed is more than 3000 m / min.

The results of Table 1 show that the cooling capacity of the spin guide is better than that of the spin tube alone, and the cross section is also good.

division Forced cooling Natural cooling Spin tube Spin Tube / Spin Guide Filament tension (g) 29.6 23.7 24.2 27.1 U 0.81 1.33 0.97 0.92 Section Distribution Good Bad Good Good

Features and other advantages of the present invention as described above will become more apparent from the following examples.

Example 1

Multifilament yarns were prepared using the apparatus of FIG. 2. At this time, the detention was made of yarn with a single fineness 2 denier using 36 holes, the spinning speed was 5000m / min. The spinning results are shown in Table 2.

Example 2

The same procedure as in Example 1 was repeated except that the spinning speed was 4000 m / min. The spinning results are shown in Table 2.

Example 3

The same procedure as in Example 1 was repeated except that the cooling apparatus in which the spin guide of FIG. 4A was attached to the spin tube of FIG. 2 was used, and the spinning speed was 2000 m / min. The spinning results are shown in Table 2.

Example 4

A cooling apparatus in which the spin guide of FIG. 4A was attached to the spin tube of FIG. 2 was used, and yarns were manufactured using single holes of 3 denier using 48 holes. At this time, the spinning speed was 5000 m / min. The spinning results are shown in Table 2.

Comparative Example 1

The same procedure as in Example 1 was repeated except that a conventional honeycomb was used as the cooling device. The spinning results are shown in Table 2.

Comparative Example 2

The procedure of Example 1 was repeated without using a cooling device. The spinning results are shown in Table 2.

Comparative Example 3

The same procedure as in Example 1 was repeated except that the spinning speed was 2000 m / min. The spinning results are shown in Table 2.

[Comparative Example 4]

Multifilament yarns were prepared using the apparatus of FIG. 2. At this time, the detention was made of yarn with a single fineness 3 denier using 48 holes, the spinning speed was 5000m / min. The spinning results are shown in Table 2.

division Single Sand Island (De ') Cooling equipment Spinning speed (m / min) Fair Fairness U section Example 1 2 Spin tube 5000 Good 0.97 Good Example 2 2 Spin tube 4000 Good 0.96 Good Example 3 2 Spin Tube / Spin Guide 2000 Good 1.02 Good Example 4 3 Spin Tube / Spin Guide 5000 Good 1.05 Good Comparative Example 1 2 Forced cooling 5000 Good 0.81 Good Comparative Example 2 2 Natural cooling 5000 Bad 1.33 Bad Comparative Example 3 2 Spin tube 2000 usually 1.23 Bad Comparative Example 4 3 Spin tube 5000 Bad 1.41 Bad

As described above, the apparatus of the present invention allows the air to be sucked by the traveling speed of the multifilament yarn without the need for a separate cooling wind supply device, thereby achieving effective cooling by natural cooling by the formation of airflow instead of forced cooling. This makes it possible to manufacture yarns that are significantly reduced in manufacturing costs because the equipment is very simple and the external air cooling and humidity maintenance are unnecessary.

Claims (2)

In the apparatus for cooling the melt-spun multifilament yarns, At least one porous cylindrical spin tube 21 is formed in the advancing direction of the multifilament yarns and the air inlet hole of a diameter of 1 ~ 5mm at a predetermined interval on the wall, and Multi-filament yarn cooling device characterized in that the outer side of the spin tube is provided with a space between the spin tube at a predetermined interval and arranged in parallel to the vortex generation preventing windbreak plate (22). 2. An air inlet (23a) according to claim 1, which is intended to be attached to the upper portion of the spin tube (21), has a cylindrical shape in the form of a double wall having a space therein, and is connected to an external air source, and is formed on the wall surface. The multifilament yarn cooling apparatus further comprises a spin guide (23) having a plurality of air injection holes (23b) in the.