JPH0684565B2 - Synthetic fiber melt spinning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention suppresses the generation and growth of foreign matter deposited around the nozzle of the spinneret, which is the main cause of the spinning process slump in melt spinning of high molecular polymers, for spinning. The present invention relates to a melt-spinning apparatus for improving the process condition and producing fibers with less yarn unevenness and good quality, that is, excellent strength and elongation characteristics.

[Prior Art] In melt spinning of a high-molecular polymer, a phenomenon in which foreign matter is deposited around the nozzle of the spinneret with the passage of time has been recognized, and it is well known that this is the main cause of deterioration of the spinning process. It is being done. Therefore, the spinneret surface is kept good by regularly cleaning the spinneret surface or replacing the spinneret. However, the cost for this-labor cost, polymer loss, opportunity loss, etc.- Since it is a considerable amount, cleaning the surface of the spinneret and reducing the frequency of replacement of the spinneret have been an important subject for a long time for a fiber manufacturing engineer.

Conventionally, various methods have been proposed for suppressing foreign matters accumulated around the nozzle of a spinneret.

In particular, in the case of a polymer containing polyethylene terephthalate as a main component, the mechanism of generation and growth of foreign substances is still unknown, but when the components of the foreign substances are analyzed, the sublimable substances are the main ones. It is known that it is possible to suppress the generation and growth of foreign matter deposited on the die surface by discharging the atmosphere containing a large amount of the outside of the system. From such a point of view, it is known just below the base. From such a point of view, a method has been proposed in which the atmosphere immediately below the mouthpiece surface is sucked in, or gas is blown from the outside and the atmosphere immediately below the mouthpiece surface is exhausted, but immediately below the mouthpiece surface, the polymer still solidifies. Since it is in a non-flowing state, it is not preferable to blow or suck gas from the outside or to give a disturbance to cause yarn unevenness. Further, if the atmosphere just below the die surface is exhausted, the temperature just below the die surface will drop, and the strength and elongation of the obtained fiber will be low, which is also unfavorable. It has been impossible with the methods proposed hitherto to achieve both suppression of foreign matter accumulated on the spinneret surface, that is, improvement of the spinning process tone and improvement of yarn unevenness and yarn quality.

[Object of the Invention] The present inventors have arrived at the present invention as a result of diligent studies to reduce foreign matter deposited on the spinneret surface, improve the tone of the spinning process, and obtain fibers having 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 delay cooling unit and a cooling air blowing surface are arranged in this order from the top, and the delay cooling unit has a length of 40 to 200 mm and the delay Inside the cooling part, a truncated cone-shaped cylindrical heater with a diameter of the upper end opening 10 to 20 mm larger than the outermost circumference of the polymer discharge hole of the mouthpiece is installed at a position 10 to 30 mm below the mouthpiece, and the surface of the mouthpiece and the upper end of the tubular heater are This is a melt spinning apparatus for synthetic fibers, characterized in that a natural exhaust type exhaust hole is provided at a position between them.

Hereinafter, the present invention will be described with reference to the drawings.

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

In the figure, 1 has a spinneret 2 for discharging molten polymer by a spin pack arranged in a spin block 9.

Reference numeral 3 denotes a shutter for preventing the yarn cooling air from rising non-uniformly in the direction of the spinneret surface and for securing the delayed cooling portion 8. The shutter 3 has a yarn passage hole 3a and is provided at the front and rear of the central portion thereof.
It is divided.

Reference numeral 4 denotes a yarn cooling air blowing surface, and 5 denotes a yarn cooling chamber. Reference numeral 6 is a truncated cone-shaped cylindrical heater having a diameter of the upper end opening installed in the delay cooling unit 8 that is 10 to 20 mm at the outermost periphery of the polymer discharge hole of the base, and the upper end is installed 10 to 30 mm below the base. It

An exhaust port 7 is provided with a plurality of holes at a position between the spinneret 2 and the upper end of the tubular heater 6. As the shape of the exhaust hole 7, any shape such as a circular shape or a rectangular shape can be used.

The delay cooling unit 8 is composed of a space formed between the lower surface of the base 2 and the lower surface of the shutter 3, and the periphery thereof is mainly surrounded by the heat insulating material 10.

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

As described above, the present invention makes it possible to suppress foreign matter deposited on the spinneret surface, that is, to improve both the spinning process tone and the yarn unevenness and yarn quality, for the following reasons. Can be thought of as.

Conventionally, as a cause of generation and growth of foreign matters accumulated around the spinneret nozzle, which is the main cause of the spinning process disorder, sublimable components of the discharged polymer stream are around the discharge holes on the spinneret surface (hereinafter simply referred to as discharge holes). It is believed that most of them adhere to the periphery) and are gelled on the surface of the die due to oxidative deterioration and deposited as solid foreign matter.

From this, as a method for discharging the atmosphere containing a large amount of sublimate to the outside of the system, there is proposed a device utilizing a stack effect by penetrating a vertical hole in a pack as shown in JP-A-53-78315. In this case, it was difficult to increase the exhaust amount because the pack was cooled and there was a space problem.

The present invention overcomes this problem and suppresses foreign matter deposited on the die surface without performing costly forced exhaust, and when the truncated cone-shaped tubular heater 6 is installed as in the present invention, The atmosphere outside the spinning system, that is, the atmosphere containing a large amount of sublimate due to the temperature difference from the outside air is naturally discharged from the exhaust hole 7.

In addition, with respect to the accompanying flow caused by the yarns, the ascending airflow that does not contain sublimate rising toward the delay cooling section 8 and the die surface 2 rises to the die surface 2 very efficiently and the exhaust hole 7 Since the atmosphere is more naturally discharged and the atmosphere around the die surface 2 is constantly updated with an atmosphere containing no sublimate, foreign matter accumulated on the die surface can be significantly suppressed.

Here, if the diameter of the upper end opening of the cylindrical heater is smaller than 10 mm from the outermost circumference of the polymer discharge hole of the die, yarn contact may occur, and if it is larger than 20 mm, the ascending airflow containing no sublimate efficiently reaches the die surface. It does not rise toward the bottom and the atmosphere around the mouthpiece surface cannot be updated sufficiently. Similarly, when the upper end opening of the tubular heater is closer than 10 mm below the mouthpiece, the natural exhaust volume is reduced, and when it is more than 30 mm, the upward airflow toward the mouthpiece surface is difficult to efficiently rise toward the mouthpiece surface, which is not preferable.

On the other hand, when the atmosphere under the die surface is evacuated, the temperature of the die surface and the atmosphere under the die decreases, and the strength and elongation of the fiber decreases, that is, the yarn quality deteriorates. By heating the lower atmosphere temperature, the spinneret surface and the yarn are heated, so that the strength and elongation of the fiber is improved without being lowered.

The heater according to the present invention preferably uses a far-infrared ceramic heater in order to make the operating temperature range wide, but the heater is not necessarily limited to this.

In the specific examples, the case where one yarn is spun is shown, but the present invention is not limited to these, and it goes without saying that the same can be done when spinning an arbitrary number of yarns.

Example A polyethylene terephthalate having an intrinsic viscosity of 0.635 (measured in o-chlorophenol at 35 ° C.) of 0.635 was used by using a spinning device having a spinning tube in which cooling air is blown from one direction as shown in FIGS. Melt spinning was performed at 1200 m / min to obtain 50 denier / 36 filament yarn.

At this time, the far-infrared ceramic heater is used as the circular truncated cone-shaped heater, and the exhaust holes have a rectangular cross section and the same size natural exhaust method is used on both the front and rear surfaces of the spinning device. Was 15 cm ² for each.

The results are shown in the table below. The length of the delay cooling unit is
90 mm, spinneret polymer discharge hole outermost pitch circle is 500 m
m, cooling air volume is 4 Nm ³ / min.

Here, the presence of the truncated cone-shaped tubular heater means that the temperature of the die and the atmosphere of the die decreased by the exhaust is corrected to the temperature when the exhaust is not exhausted (level NO.1).

However, for the level No. 10, as a comparative example, a truncated cone-shaped tubular heater was installed, but heating, that is, temperature correction was not performed.

Regarding the level with heating without exhaust (NO.2), the case of increasing the die temperature by 10 ° C is shown as a comparison.

The spinning process condition is that the spinneret surface is cleaned when spinning breakage occurs twice or more in eight hours, and is represented by an average spinneret cleaning cycle (unit: day).

The yarn quality is measured by using a drawn yarn, and the uneven stain is 3.5 or more, which is a good level when visually judged by the 5-point method, but the higher the better. Further, U% is a good level of 0.7% or less, but the lower the better.

From the above results, a truncated cone-shaped cylindrical heater with a diameter of the upper end opening 10 to 20 mm larger than the outermost circumference of the polymer discharge hole of the mouthpiece was installed in the delay cooling section at a position 10 to 30 mm below the mouthpiece, and further from the exhaust hole. By adjusting the heater to compensate for the decrease in the temperature of the spinneret surface and the ambient temperature below the spinneret due to natural exhaustion, the spinning tone can be controlled without deteriorating the yarn unevenness (U%, dyed spots) and the yarn quality (stretchability). It can be seen that it can be remarkably improved as compared with the method.

It has been confirmed from a microscope observation of the spinneret nozzle surface that a good cause of the spinning process condition corresponds to a decrease in the amount of foreign matter deposited around the nozzle (spinning hole) of the spinneret.

[Effects of the Invention] As described in detail above, according to the present invention, the generation and growth of foreign matters deposited around the nozzle of the spinneret can be suppressed, the spinning process tone can be improved, and a fiber with good yarn spots and yarn quality can be obtained. It becomes possible to obtain it stably.

Further, it can be said that this is a very effective melt spinning device 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 were conventionally considered as reciprocal phenomena.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a specific example of the present invention, and FIG.
It is a XX sectional arrow line view of a figure. 1 ... Spin pack, 2 ... Spinneret 3 ... Shutter 4 ... Yarn cooling air blowing surface, 6 ... Frustum-conical cylindrical heater 7 ... Exhaust hole, 8 ... Delay cooling unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Takamoto 77, Kitayoshida-cho, Matsuyama-shi, Ehime Prefecture Matsuyama Factory, Teijin Limited (56) Bibliography Sho 51-82807 (JP, U) JP 46-2126 (JP, B1) JP 58-25762 (JP, B2)

Claims (1)

[Claims] 1. A melt spinning apparatus in which a spinneret pack, a delay cooling section and a cooling air blowing surface are arranged in this order from the top,
The length of the delay cooling section is set to 40 to 200 mm, and the truncated conical cylindrical heater having a diameter of the upper end opening in the delay cooling section is 10 to 20 mm larger than the outermost periphery of the polymer discharge hole of the mouthpiece is 10 to 30 mm below the mouthpiece. 1. A synthetic fiber melt-spinning device characterized in that a natural exhaust type exhaust hole is provided at a position between the spinneret surface and the upper end of the tubular heater.