JPS63275706A - Apparatus for melt spinning synthetic fiber - Google Patents

Abstract

PURPOSE:To obtain the titled apparatus, having a spinneret pack, specific delayed cooling part and cooling air blow-off surface successively installed from the upper part and excellent spinning process condition and providing a fiber having excellent yarn unevenness and quality. CONSTITUTION:A cylindrical heater 6 in the form of truncated cone having the diameter of the upper end opening 10-20cm larger than that of polymer discharge holes in the outermost periphery of a spinneret 2 is provided in a delayed cooling part 8 which is a space 1 between the undersurface of the spinneret 2 of a spinning pack and the undersurface of a shutter 3. The upper end of the heater 6 is placed at a position 10-30cm below the spinneret and plural vent holes are perforated at positions between the spinneret and the upper end of the cylindrical heater.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention suppresses the generation and growth of foreign matter that accumulates around the nozzle of the spinneret, which is the main cause of poor spinning process in melt spinning of high molecular weight polymers. The present invention relates to a melt spinning apparatus that improves process performance and produces fibers with less yarn unevenness and good quality, that is, good strength and elongation characteristics.

[Prior Art] In the melt spinning of high-molecular polymers, it has been observed that foreign matter accumulates around the nozzle of the spinneret over time, and this is often the main cause of deteriorating the quality of the spinning process. It is a known place. For this reason, the spinning process is maintained in good condition by regularly cleaning the spinneret surface or replacing the spinneret, but this costs money - labor costs, polymer losses, opportunity losses, etc. The cost is considerable, and reducing the frequency of cleaning the spinneret surface and replacing the spinneret has long been an important issue for textile manufacturing engineers.

Conventionally, various methods have been proposed in order to suppress foreign matter accumulating around the nozzle of a spinneret.

Particularly in the case of polymers whose main component is polyethylene terephthalate, the mechanism of generation and growth of foreign substances is still unknown, but analysis of the foreign substances reveals that they are mainly sublimable, so sublimated particles directly below the mouth surface. It is known that the generation and growth of foreign matter deposited on the mouthpiece surface can be suppressed by discharging an atmosphere containing a large amount of . From this point of view, methods have been proposed to exhaust the atmosphere directly under the mouthpiece surface by suctioning the atmosphere directly under the mouthpiece surface or by blowing gas from outside, but the polymer still solidifies directly under the mouthpiece surface. Since it is in a non-flowing state, blowing or suctioning gas from the outside or giving it any disturbance will cause thread unevenness, which is undesirable.Furthermore, if the atmosphere directly under the nozzle surface is exhausted, the temperature directly under the nozzle surface will drop. The strength and elongation of the resulting fibers is low, which is also undesirable from this point of view.The conventionally proposed method is aimed at suppressing foreign matter deposited on the spinneret surface, that is, improving the spinning process condition and improving yarn unevenness and yarn quality. It was impossible to achieve both.

[Object of the Invention] The present inventor has arrived at the present invention as a result of intensive studies aimed at reducing foreign matter deposited on the spinneret surface, improving the quality of the spinning process, and obtaining fibers with good yarn unevenness and yarn quality. .

[Structure of the Invention] That is, the present invention provides a melt spinning apparatus in which a spinneret pack, a delayed cooling section, and a cooling air blowing surface are arranged in this order from above, in which the length of the delayed cooling section is set to 40 to 200 mm, and the length of the delayed cooling section is set to 40 to 200 mm. A truncated cone-shaped cylindrical heater whose upper end opening diameter is 10 to 20++ m larger than the outermost circumference of the polymer discharge hole of the mouthpiece is installed in the cooling section at a position between 10 and 30 meters below the mouthpiece, and a cylindrical heater is installed between the mouthpiece surface and the upper end of the cylindrical heater. This is a synthetic fiber melt spinning apparatus characterized by having an exhaust hole formed between the two.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a longitudinal cross-sectional view showing a specific example of the present invention, and FIG. 2 is a cross-sectional view taken along line xx' in FIG.

In the figure, reference numeral 1 has a spinneret 2 for discharging molten polymer from a spinning pack disposed in a spin block 9.

Reference numeral 3 denotes a shutter for preventing the yarn cooling air from blowing unevenly toward the spinneret surface and for securing the delayed cooling section 8. The shutter 3 has a yarn passage hole 3a and is divided into two parts, front and rear from the center. has been done.

4 is a blowing surface for yarn cooling air, and 5 is a yarn cooling chamber. Reference numeral 6 is a cylindrical heater in the shape of a truncated cone, whose upper end opening has a diameter 10 to 20 m larger than the outermost circumference of the polymer discharge hole of the mouthpiece, and the upper end is installed at a position 10 to 30 meters below the mouthpiece. be done.

Reference numeral 7 indicates an exhaust port, and a plurality of holes are formed between the spinneret 2 and the upper end of the cylindrical heater 6. As the shape of the exhaust hole 7, any shape such as circular or square can be used.

The delayed cooling section 8 is constituted by a space formed between the lower surface of the base 2 and the lower surface of the shutter 3, and is mainly surrounded by a heat insulating material 10.

In such a device, the yarn Y discharged from the spinneret 2 travels through the space of the delayed cooling section 8 surrounded by the cylindrical heater 6, the shutter 3, etc., reaches the cooling chamber 5, and is blown out from the cooling air blowing surface. It is cooled and solidified by the cooling air. In this case, the delayed cooling section 8 needs to have an appropriate length of 40 to 200 mm in order to obtain fibers with good yarn unevenness and yarn quality. If the length is shorter than 4 On+m, the yarn unevenness will worsen and the fiber will have low strength and elongation, and if it is longer than 200, the fiber will have poor yarn unevenness.

As described above, the present invention suppresses foreign matter deposited on the spinneret surface, that is, improves the quality of the spinning process and prevents yarn unevenness.

This has made it possible to achieve both improvement in yarn quality, and the reason for this is thought to be as follows.

Conventionally, it has been known that among the components of the discharged polymer flow, sublimable substances are deposited around the discharge hole on the spinneret surface (hereinafter simply referred to as discharge hole) as a cause of the generation and growth of foreign matter that accumulates around the spinneret nozzle, which is the main cause of poor performance in the spinning process. It is believed that the majority of these particles adhere to the surrounding area (referred to as the surrounding area), gel on the mouth surface due to oxidative deterioration, etc., and deposit as solid foreign matter.

For this reason, as a method for discharging an atmosphere containing a large amount of sublimate to the outside of the system, a device has been proposed that uses a chimney effect by penetrating a vertical hole in the pack, as shown in Japanese Patent Application Laid-Open No. 53-78315. In this case, it was difficult to increase the displacement due to the fact that the pack would get cold and there would be space issues.

The present invention overcomes this problem and suppresses the accumulation of foreign matter on the mouthpiece surface without the need for costly forced exhaust.When the cylindrical heater 6 in the shape of a truncated cone is installed as in the present invention, The atmosphere containing a large amount of sublimate due to the temperature difference with the outside of the spinning apparatus system, that is, with the outside air, is naturally exhausted from the exhaust hole 7.

In addition, the delay cooling section 81 prevents the accompanying flow caused by the yarn.
The rising air flow that does not contain sublimate and rises toward the heavy alloy 2 rises toward the mouthpiece surface 2 very efficiently, and the exhaust hole 7
Since the atmosphere is more naturally discharged and the atmosphere around the mouthpiece surface 2 is always renewed with an atmosphere that does not contain sublimate, foreign matter deposited on the mouthpiece surface can be significantly suppressed.

Here, if the diameter of the opening at the upper end of the cylindrical heater is smaller than 10 mm from the outermost circumference of the polymer discharge hole of the cap, there is a risk of thread hitting, and if it is larger than 20I1111, the upward air flow that does not contain sublimate can be efficiently flowed to the cap surface. Similarly, if the upper end opening of the cylindrical heater is closer than 10mm below the cap, the natural exhaust volume will decrease, and if it is farther than 30mm below the cap, the natural exhaust volume will decrease. This is undesirable because it becomes difficult for the upward airflow toward the surface to efficiently rise toward the mouth surface.

On the other hand, when the atmosphere under the nozzle is exhausted, the temperature of the atmosphere on the nozzle surface and above the nozzle decreases, and the strength and elongation of the fibers decreases, that is, the yarn quality deteriorates. By heating the upper atmosphere temperature, the die surface and the yarn are heated, so that the strength and elongation of the fibers does not decrease but rather improves.

Although it is preferable to use a far-infrared ceramic heater as the heater according to the present invention in order to widen the operating temperature range, the heater is not necessarily limited to this.

In the specific example, a case where one thread is spun is shown, but it goes without saying that the present invention is not limited to this, and the same method can be applied to spinning any number of threads.

Example A spinning device having a spinning tube from which cooling air is blown out from one direction as shown in Figures 1 and 2 was used, and polyethylene terephthalate having an intrinsic viscosity (measured at 35°C in 0-chlorophenol) of 0.635 was used. was melt-spun at a spinning speed of 1200 m/min to obtain a yarn of 50 denier and 736 filaments.

At this time, the truncated conical cylindrical heater uses a far-infrared ceramic heater, and the exhaust hole has a rectangular cross section and uses a natural exhaust method with the same size on both the front and rear sides of the spinning device. The diameter was set to 15 cd each.

The results are shown in the table below. The length of the delayed cooling section is 90 mm, and the outermost pitch circle of the polymer discharge hole of the spinneret is 5 mm.
0[Im, cooling air volume is 4Nm3/min.

7. There is a 91st term.

Here, the presence of a truncated conical cylindrical heater means that the reduction in the temperature of the cap and the atmosphere above the cap due to exhaust gas is corrected by heating to the temperature (level N01) when no gas is exhausted.

However, for water*Na'IO, as a comparative example, a cylindrical heater in the shape of a truncated cone was installed, but heating, that is, temperature correction was not performed.

Regarding the level with heating without exhaust (NO3), a case in which the cap temperature was increased by 10°C was described as a comparison.

The spinning process condition is expressed as the average spinneret cleaning cycle (in units of three days), with the spinneret surface being cleaned when yarn breakage occurs twice or more in 8 hours.

Yarn quality is measured using a drawn yarn, and staining spots are visually judged using a 5-point method, and a score of 3.5 or higher is a good level, but the higher the score, the better. Further, a good level of U% is 0.7% or less, but the lower the better.

Based on the above results, a cylindrical heater with a truncated conical shape, the diameter of whose upper end opening is 10 to 20 times larger than the outermost circumference of the polymer discharge hole of the mouthpiece, was installed in the delayed cooling section at a position of 10 to 30III below the mouthpiece, and an exhaust hole was also installed. By using the heater to compensate for the drop in the ambient temperature on the spindle surface and the top of the spinneret due to more natural exhaust, the spinning condition can be improved without deteriorating yarn unevenness (U%, dyeing spots) or yarn quality (strength and elongation). It can be seen that the results are significantly improved compared to the conventional method.

The reason why the spinning process is in good condition is due to the spinneret nozzle (
This was confirmed by microscopic observation of the gold medal surface of the spinning hole (spinning hole).

[Effects of the Invention] As described in detail above, the present invention suppresses the generation and growth of foreign matter that accumulates around the nozzle of the spinneret, improves the spinning process, and prevents yarn unevenness and produces fibers with good yarn quality. It becomes possible to obtain stable results.

Furthermore, it can be said that it is an extremely effective melt spinning apparatus in that it satisfies both the suppression of foreign matter deposited on the spinneret surface and the improvement of yarn unevenness and yarn quality, which have conventionally been considered contradictory phenomena.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a specific example of the present invention, and FIG.
FIG.

Claims (1)

[Claims] In a melt spinning apparatus in which a spinneret pack, a delayed cooling section, and a cooling air blowing surface are arranged in this order from above, the length of the delayed cooling section is 40 to 200 mm, and the diameter of the upper end opening in the delayed cooling section is that of the spinneret. A cylindrical heater in the shape of a truncated cone, which is 10 to 20 mm larger than the outermost circumference of the polymer discharge hole, is installed at a position 10 to 30 mm below the cap, and an exhaust hole is drilled between the cap surface and the upper end of the cylindrical heater. A synthetic fiber melt spinning device featuring: