JPS62184107A - Cooling method in melt-spinning process - Google Patents

Abstract

PURPOSE:To obtain a uniform yarn free from unevenness even by high-speed spinning of a thick-denier yarn, by placing a horizontally blowing cooling apparatus and a vertically blowing cooling apparatus under a spinneret for melt spinning in the order and controlling the temperature and flow rate of blown cooling air stream. CONSTITUTION:A horizontally blowing cooling apparatus 3 blowing cooling air along a direction crossing a spun yarn 6 is placed below a spinneret 1. A vertically blowing cooling apparatus 4 is placed under the horizontally blowing apparatus 4. The vertically blowing apparatus 4 is furnished at its top with a blowing nozzle 7 to blast cooling air along the running direction of the spun yarn 6 and an exhaustion port 8 at the bottom. The exhaust air temperature is detected by a sensor 9 attached to the exhaustion port 8 and the flow rate and/or temperature of the cooling air blown from the blowing nozzle 7 are controlled in a manner to keep the exhaust temperature at a definite level.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a melt-spinning cooling method for obtaining thermoplastic synthetic fibers by a melt-spinning method.

(Prior art) Conventionally, as a manufacturing method for thermoplastic fibers such as polyamide fibers and polyester fibers, after melt spinning, cooling air is blown from the direction across the running yarn (on one side or in the circumferential direction) to cool and solidify the fiber. After that, a method of applying an oil and rolling it up is adopted.

In recent years, there has been a remarkable increase in the winding speed of spinning yarns and the increase in fineness for use in industrial materials.As a result, conventional manufacturing methods have frequently encountered problems in operability and quality due to uneven cooling of the yarn. Normally, the cooling area and winding area are separated by the floor (ceiling) of the building and are separated by floor, and the part where the yarn passes is communicated with a cooling cylinder, but there is a temperature-controlled circulating air volume between each room. There are also differences in the amount of cooling air for the spun yarn, pressure differences caused by the accompanying airflow of the running yarn, and especially pressure fluctuations when using an air processing device such as an air aspirator. This pressure difference is
Because the pressure is equalized through the cooling cylinder.

Inside the cooling cylinder, the direction of the airflow, the amount of airflow, etc. are not uniform, and therefore there is a temperature difference between the plurality of cooling cylinders, and there is a drawback that the quality of the yarn varies greatly due to uneven cooling.

In addition, even if the pressure is the same on the upper and lower floors, the accompanying airflow generated by the running of each thread flows from the upper floor to the lower floor, so it is unavoidable that a small local pressure difference will occur. Updrafts and downdrafts occur almost alternately in the cooling cylinders, creating temperature differences between the cooling cylinders, and furthermore due to temperature differences between the two floors and uneven cooling in the cooling area of each yarn. Due to the unevenness in the amount of heat brought in, the temperature variation within each cooling cylinder is further exacerbated, and this is a major factor in the occurrence of quality unevenness in strength, elongation, dyeability, etc. between yarns.

Various proposals have been made as measures against this accompanying airflow.

For example, in Japanese Patent Application Laid-Open No. 58-174615, an exhaust chamber is provided at the bottom of the cooling cylinder to collect the accompanying flow of yarn, and the exhaust chamber is connected to the outlet provided directly below the air outlet through a return pipe. , a method has been proposed in which the accompanying flow of yarn passes through a return pipe and is again blown out from an outlet. However, this method is a method to prevent troubles caused by yarn wobbling, and because airflow is circulated in the cooling cylinder, this method is not suitable for high-speed spinning or melt spinning of yarn with a large fineness, especially for yarns with a large single filament fineness. In this case, the atmospheric temperature inside the cooling cylinder changed over time, making it impossible to obtain yarn of uniform quality due to cooling spots.

Further, in Japanese Utility Model Publication No. 58-37959, an exhaust pipe is provided at the lower part of the cooling pipe (intermediate duct), and.

A method has been proposed in which an intermediate opening is provided between the blow cooling device (air blower tube) and the cooling tube, and outside air is introduced from the intermediate opening, but this causes variations in outside air temperature and introduced air volume.
It is difficult to control the temperature inside the cooling cylinder, and therefore, as before, yarns of uniform quality cannot be obtained.

(Problems to be Solved by the Invention) As mentioned above, in the conventional melt-spinning cooling method, the occurrence of quality unevenness due to uneven cooling was unavoidable, but the present invention improves strength, elongation, and dyeability. The technical problem is to provide a melt spinning cooling method that can produce thermoplastic synthetic fibers with uniform quality.

(Means for Solving the Problems) That is, the present invention provides a blowing cooling device that blows cold air below a spinneret from a direction across the yarn.

It has an outlet at the top that blows out cold air in the yarn running direction.

Cooling cylinders each having an air outlet at the bottom thereof are sequentially provided along the thread running direction, the temperature of the air outlet is detected, and the amount and/or temperature of the cold air at the outlet is adjusted so that the temperature remains constant. The gist of the present invention is a melt-spinning cooling method characterized by the following.

The present invention will be explained in detail below based on the accompanying drawings.

FIG. 1.2 shows an example of a spinning cooling device used in the present invention. Below the spinneret 1, a heater 2 and a spray cooling device are installed along the running direction of the spun yarn 6. 3.
Cooling cylinder 4. The oiling device 5 is provided in this order.

The spray cooling device 3 is operated in a direction across the yarn 6 (substantially perpendicular direction).
This is for cooling the yarn 6 by blowing cold air, and the length of the blowing cooling area is 0.5 to 2. Om.

The width is 0.1~0.5m, the blowing wind speed per spindle is 0.2~
The speed is in the range of 2.0 m/sec, and varies depending on the brand being spun.

A thread 6 is attached to the upper part of the cooling tube 4 located below the spray cooling device 3.
The blower lower blows out cold air in the direction of travel.

An air exhaust port 9 is provided in the lower part near the outlet 8 of the yarn 6. The temperature of the air exhaust port 9 is detected by a temperature sensor 10 attached to the air exhaust port 9, and the air volume control valve 11 is activated based on this detection signal. By operating it, the amount of cold air blown out from the blow-off lower can be increased or decreased, and the temperature of the air exhaust port 9 can be controlled to be constant. As a method of controlling the temperature of the air outlet 9, in addition to increasing or decreasing the amount of cold air blown out from the blowout lower, a method of adjusting the temperature of the cold air blown out, or a method of adjusting both the temperature and amount of the cold air is adopted. be able to. Alternatively, the temperature of the exhaust port 9 may be detected intermittently, and the temperature and/or air volume of the cold air may be adjusted based on the signals to keep the temperature of the exhaust port 9 constant.
Connect the temperature detection of the exhaust port 9 and the temperature and/or air volume adjustment device of the cold air.

Automatic constant control is preferable.

The flow rate of cold air at the blowout lower varies depending on the diameter of the cooling cylinder 4, but is 0.5 to 2 if the diameter is about 0.3 m.
．． The temperature of the exhaust air at the exhaust port 9 is detected by setting the temperature to 5r&/min., and the amount of cold air and the temperature of the cold air are adjusted so that the temperature is constant. Is the cold air flow rate 0.5r+? /min/weight, the airflow inside the cooling cylinder 4 becomes unstable and it becomes difficult to keep the temperature inside the cooling cylinder 4 constant.
When the flow rate exceeds 2.5 m/min/weight, the yarn 6 swings violently.

This is undesirable because it causes thread breakage, uneven thickness, etc. In addition.

The cold air blown from the blowing cooling device 3 or the blowing lower blower is normally in the range of 5 to 30°C and 30 to 80% humidity. Cold air may be supplied to the blowing cooling device 3 and the blowing lower from separate cold air ducts, but as shown in Fig. 1, it is preferable to supply cold air from the same cold air duct 12. The branched cold air may be supplied into the cooling cylinder 4 from the blowout lower via the temperature adjustment means and/or the air volume adjustment valve 11.

The shape of the cooling cylinder 4 is preferably circular in cross section as shown in FIG. 1.2, but in the case of multiple spinning, it may be semicircular in cross section or square in cross section as shown in FIG. 3.

The length of the cooling tube 4 is approximately 2 to 8 m.

In the apparatus shown in FIG. 1, the air outlet 9 and the thread outlet 8 are provided separately, but the outlet 8 may also be used as the air outlet 9.

(Function) Next, an embodiment of the present invention using the apparatus shown in FIG. 1 will be described.

The yarn 6 spun from the spinneret 1 is cooled and solidified by cold air from the blow cooling device 3, and then guided into the cooling cylinder 4. In the cooling cylinder 4, a downward airflow is generated by the cold air blown out from the blowout lower, and the temperature of the discharged air at the exhaust port 9 is detected by the temperature sensor 10, and the blowout is adjusted so that the temperature remains constant. The lower air volume is adjusted by a control valve 11. The yarn 6 that has been cooled and solidified by the blown cooling air passes through the cooling tube 4 whose exhaust port 9 is kept at a constant temperature, and is uniformly cooled. Subsequently, the yarn 6 is applied with an oil agent in the oiling device 5, and then
It is rolled up.

As mentioned above, after the yarn spun from the spinneret is spray cooled, it is cooled in a cooling cylinder where the temperature of the exhaust port at the bottom is controlled at a constant level. It is possible to prevent the occurrence of quality irregularities such as strength and elongation.

Since the present invention can uniformly cool the yarn, it is particularly effective when spinning at high speed or when spinning yarn with a single yarn fineness of 8 d or more, particularly 15 d or more.

(Example) The present invention will be explained in more detail below using examples.

Example 1. Comparative Example 1 25°C for a solution of Ig/100cc in 96% sulfuric acid
Nylon 6 with a relative viscosity of 2.6 measured at 26
It was melt-spun at 0°C, taken up using the equipment shown in Figure 1 under the conditions shown in Table 1, and then hot-stretched in a conventional manner, then subjected to indentation crimping using heated and pressurized air, and then rolled up. . Note that a non-aqueous oil agent was used and was applied immediately before stretching.

Further, a yarn of Comparative Example 1 was obtained in the same manner as in Example 1, except that the blow-off from the upper part of the cooling cylinder was not performed.

The situation inside the cooling cylinder of Example 1 and Comparative Example 1.

Table 2 shows the test results of the dyeability of the obtained yarn.

Example 2. Comparative Example 2 Nylon 6 with a relative viscosity of 3.10 measured at 25° C. for a 1 g/100 cc solution in sulfuric acid.

It was melt-spun at 280° C., cooled and solidified using the apparatus shown in FIG. 1, and after applying a water-based oil agent, it was taken up and wound up at 1050 m/min. The wound undrawn yarn was hot-stretched at 180° C. at a draw ratio of 3.6 to obtain a yarn of 210 d/24 f.

In addition, the cold air of the blowing cooling device is 20°C, Q, 5m/sec,
The air blowing from the top of the cooling cylinder is 20℃ and 0.9n? /min/weight (standard air volume), and the temperature of the air outlet was adjusted to 26±1''c by adjusting the air volume from the air outlet with an air volume control valve.

Also, except for not blowing out the top of the cooling cylinder.

A yarn of Comparative Example 2 was obtained in the same manner as in Example 2.

The situation inside the cooling cylinder in Example 2 and Comparative Example 2.

Table 3 shows the strength and elongation of the obtained yarn.

Furthermore, the strength of the yarn obtained by drawing the undrawn yarn of Example 2 at a draw ratio of 3.7 was improved compared to the yarn shown in Table 3.

Moreover, the drawing operability was also more stable than in Comparative Example 2.

(Effect of the invention) The present invention has the configuration described above.

After the yarn spun from the spinneret is blown and cooled, it is cooled in a cooling cylinder with a constant temperature at the exhaust port at the bottom. It is possible to prevent quality unevenness from occurring. Since the present invention can uniformly cool the yarn, it is extremely effective particularly in high speed spinning and spinning of large fineness yarns.

[Brief explanation of drawings]

FIG. 1 is a schematic front sectional view of a spinning cooling device used in the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a plan view of a spinning cooling device having a rectangular cross section with an air outlet on one side. 1: Spinneret 3: Spray cooling device 4: Cooling cylinder 7: Air outlet 9: Exhaust port 10: Temperature detector 11 Two control valves

Claims (1)

[Claims] (1) Below the spinneret, there is a blowing cooling device that blows cold air from the direction across the yarn, and a cooling cylinder that has an air outlet at the top that blows out cold air in the yarn running direction, and an exhaust port at the bottom. A melt-spinning cooling method characterized in that the temperature of the air outlet is detected and the amount and/or temperature of the cold air at the outlet is adjusted so that the temperature is constant.