JPH0441711A - Method for spinning polyester fiber at high speed - Google Patents

Abstract

PURPOSE:To spin polyester fiber at a high speed with excellent homogeneity and operating efficiency by blowing a heated gas from a heating cylinder arranged just under the surface of a spinneret on extruded filaments under specific conditions, quenching and solidifying the filaments with a cooler just under the heating cylinder. CONSTITUTION:A polyester polymer (e.g. polyethylene terephthalate) is melt extruded through a spinneret 1 and taken off at >=5000m/min speed. In the process, a heated gas (e.g. air) at 200-500 deg.C temperature is blown from a heating cylinder 6, installed just under the spinneret 1 and having 5-20cm length on extruded filaments 4 at 0.05-0.8m/sec, preferably 0.1-0.5m/sec wind velocity and the filaments 4 are then quenched and solidified with a cylindrical type cooler 3 arranged just under the heating cylinder 6 to carry out spinning of polyester fiber at the high speed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for high-speed spinning of polyester fibers, and more specifically, it is capable of stably producing polyester multifilament yarn for clothing with good uniformity. The present invention relates to a high-speed spinning method.

(Prior Art) Generally, in high-speed spinning of polyester fibers, the spinning speed is in a speed range exceeding 5000 m/min.

The spun yarn undergoes so-called neck-like deformation during the thinning process [Reference (Internationale Chemifas)]
ertagung +nDornbirn (1979
), Journal of the Japan Textile Society, Vol. 38, No. 11.

No. 499 (1982), etc.], the neck-shaped deformation point of the sea bream changes its position drastically in the direction of the spinning line. and.

This positional fluctuation of the neck-shaped deformation point not only deteriorates the uniformity within and between the filaments of the yarn taken in one turn, but also in extreme cases causes breakage of the spun yarn.
It is difficult to stably spin the yarn.

FIG. 2 is an explanatory diagram showing one embodiment of a conventional spinning method. 1 is a spinneret with concentric triple circular holes.

2 is a non-blast heating type heating cylinder placed directly under the spinneret 1; 3 is a cylindrical cooling device placed directly below the heating cylinder 2; 4
5 is a spun yarn, and 5 is a yarn convergence guide. Note that as the yarn convergence guide, one that also serves as a nozzle type oil supply device is usually suitably used.

In the conventional spinning method, since the heating cylinder 2 is of a non-air blowing type and the only air source is the cylindrical cooling device 3, the heating cylinder 2 is
The pressure inside becomes slightly reduced, and the cooling material from the two-cylindrical cooling device 3 flows into the heating area inside the heating cylinder 2. The inventors measured the ambient temperature in the heating area and the position of the neck deformation point, and found that the cooling force flows into the heating area.

The ambient temperature near the fibers in the heated area fluctuates drastically;
Furthermore, it was discovered that the position of the neck-shaped deformation point changes unsteadily and considerably violently in the direction of the spinning line due to the fluctuation in the ambient temperature, and that this position fluctuation causes yarn shaking in the spun yarn 4. Ta. Also.

As a result of long-term observation, it was observed that when particularly severe positional fluctuations occurred, the threads often broke.

As described above, it must be said that it is still difficult to industrially produce polyester fibers with extremely stable operation and good operability in high-speed spinning of polyester fibers at a spinning speed of 5000 m/min or more.

(Problems to be Solved by the Invention) In high-speed spinning of polyester fibers at a spinning speed of 5000 m/min or more, there are problems in spinning technology as described above.

The present invention solves the above-mentioned spinning problems, and includes:
The technical objective is to provide a method for industrially producing polyester fibers with extremely stable operability and good operability at a spinning speed of 5000 m/min or more.

(Means for Solving the Problems) The present inventors have conducted intensive studies to solve the above problems, and as a result, have arrived at the present invention.

That is, one aspect of the present invention is that when a polyester polymer is melt-spun from a spinneret and taken off at a speed of 5,000 m/min or more, a polyester polymer having a length of 5 to 20 CD+ is disposed directly below the spinneret surface.
Heated gas with a temperature of 200 to 500℃ is sent from a heating cylinder at a wind speed of 0.
．． Spray onto the spun yarn at 05-0.8 m/sec.

The gist of this invention is a high-speed spinning method for polyester fibers, which is characterized in that the yarn is then cooled and solidified using a cylindrical cooling device disposed directly below the heating cylinder.

In the present invention, the polyester polymer used is generally polyethylene terephthalate, but a third component is mixed or copolymerized to the extent that the original properties of the polyester are not impaired, or a matting agent, a coloring agent, a stable It may also contain agents, antistatic agents, etc. Also, the degree of polymerization is 1.

Although there is no particular limitation as long as the fiber forming property is not impaired, the present invention is a method particularly suitable for producing polyester multifilament yarn for clothing. as a solvent, the relative viscosity measured at a concentration of 0.5 g/a and a temperature of 25°C is 1.3.
It is preferably about 0 to 1.45.

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

FIG. 1 is an explanatory diagram showing one embodiment of the spinning method of the present invention.

A feature of the present invention is that when melt spinning is performed at a spinning speed of 5,000 m/min or more, a heating cylinder 6 of a blow heating type is disposed directly below the yarn nozzle 1, and heated gas is blown onto the spun yarn 4. It is in. In the spinning method of the present invention, the heated gas C is supplied from the heating cylinder 6 and is accompanied by the spun yarn 4, so that it is blown out from the single cylindrical cooling device 3 as seen in the conventional spinning method described above. Cooling air A does not flow into the heating area.

Therefore, fluctuations in the ambient temperature in the heating region are significantly reduced, fluctuations in the position of the neck-like deformation point are also reduced, and yarn shaking and yarn breakage of the spun yarn 4 are extremely suppressed.

In the present invention, the length of the heating cylinder needs to be 5 to 20 cm. If the length of the heating cylinder is shorter than 5 cm, a sufficient heating effect on the yarn cannot be obtained, and the rapid temperature drop of the spun yarn will cause large fluctuations in the position of the neck-like deformation point, resulting in poor spinnability. This is not desirable for printing purposes. Moreover, when the length of the heating cylinder is longer than 20 cm, the absolute amount of heating gas to be supplied increases.

In addition, the distance from the spinneret surface to the yarn convergence position must be increased, leading to an increase in spinning tension.
This is unfavorable both economically and in terms of spinnability.

Next, in the present invention, the temperature of the gas blown from the heating cylinder must be 200 to 500°C.

If the gas temperature is lower than 200°C, the yarn will not be sufficiently heated, and if the gas temperature is higher than 500°C,
A sufficient cooling effect cannot be obtained in the cooling area directly under the heating cylinder, which is undesirable because it causes a decrease in the adhesion strength of the yarn.

Further, in the present invention, the speed of the gas blown from the heating tube must be 0.05 to 0.8 m/sec.

Preferably it is 0.1 to 0.5+n/sec. Wind speed is 0.
If it is less than 0.5 m/sec, a sufficient heating effect of the yarn cannot be obtained, and cooling air flows in from the cooling device directly below the heating cylinder, which is not preferable. In addition, if the wind speed is higher than 0.8 m/sec, it may cause the spun yarn to sway.

This is not preferred because the spinnability deteriorates.

Examples of the heating gas used in the present invention include inert gases such as air, nitrogen, and helium, but it is more preferable to use air in terms of equipment and cost.

The diameter, number of holes, and discharge direction of the gas blowing part of the heating cylinder are not particularly limited, but it is better to have the discharge direction slightly inclined downward from the perpendicular direction of the spinning line to reduce the accompaniment of the spun yarn as it travels. This is preferable because the airflow becomes more stable.

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

Example 1 A polyethylene terephthalate chip having a relative viscosity of 1.38 was melted using the spinning apparatus shown in FIG.

Spinning was carried out under various conditions shown in Table 1 at a spinning temperature of 295° C. through a spinneret 1 with a hole diameter of 0.20 a+, a hole number of 36 holes, a double circle hole arrangement, and an outermost hole diameter (Oll> of 6.5 cm).

The spun yarn was placed directly under the spinneret 1 with an inner diameter of 11 cm.
Through the heating cylinder 6, the inner diameter 11 disposed directly below the heating cylinder 6.
cm, temperature 20℃ from cylindrical cooling device 3 with length 30cm
After cooling the spun yarn by blowing cooling air at a blowing speed of 0.5 m/sec, the yarn is focused by a yarn focusing guide 5, which also serves as a nozzle oil supply device, and is located 120 cm below the spinneret 1. I did it. At this time, the length of the heating cylinder 6, the temperature of the heated gas, and the discharge speed were variously changed as shown in Table 1.

The bundled spun yarn is taken up by an unheated first godet roller having various surface speeds shown in Table 1, bowed, and then passed through an unheated second godet roller without drawing to a high-speed winding device. A polyethylene terephthalate fiber yarn of 75 denier/36 filaments was obtained.

Table 1 shows the observation results of the positional fluctuations of the neck-shaped deformation points.

Note that the observation results were visually observed for 5 minutes.

The range of variation in the position of the neck-shaped deformation point was evaluated in the following three stages.

○: less than 2 cm, Δ: 2C [11 or more and less than 5 cm,
X: 5cm or more. Similarly, Table 1 shows the yarn unevenness 1 strength, elongation, and initial elastic modulus of the wound yarn. In Table 1, the experimental results marked with a circle are examples, and the others are comparative examples.

Note that the method for measuring characteristic values in the present invention is as follows.

Fineness unevenness (U%) Measured by a half-inert test using a Usta yarn unevenness measuring device manufactured by Zerbega, Switzerland.

Strength and elongation were measured using Autograph DSS-500 manufactured by Shimadzu Corporation, with a sample length of 30 cm and a tensile speed of 30 cm/min.

The initial elastic modulus was determined from the initial slope of the load-elongation curve obtained when measuring the strength and elongation.

* Table 1 The evaluation results of the position fluctuation status of the neck-shaped deformation point are shown.

Experiment N11l satisfying the requirements of the present invention, 4. 5. 7
At degrees 10, 11, and 13, the fluctuation in the position of the neck deformation point was extremely small, causing no operational problems, and stable spinning was possible. Furthermore, the obtained yarn had extremely small yarn unevenness, and its 1-strength elongation and initial elastic modulus had values that were acceptable for use as clothing fibers.

On the other hand, in experiment Nα2, the length of the heating cylinder was shorter than 5 cm, so the yarn was not sufficiently heated directly under the spinneret.
Changes in the position of the neck-shaped deformation point were observed.

The thread spots were relatively large. In experiment Nα3, the blowing speed of the heated gas was lower than 0.05 m/sec, so the cooling air flowed into the heating cylinder, causing large positional fluctuations in the neck-shaped deformation point, causing single yarn breakage, and causing operational problems. There was a problem. Experiment N
In α6, the blowing speed of the heated gas was higher than 0.8 m/sec, which caused the yarn to sway.

The position of the neck-shaped deformation point varied greatly, and the thread spots were extremely large. In experiment Nα8, the length of the heating tube was 20 cm.
Because of the length, cooling was insufficient at the above-mentioned focusing position, and spinning was impossible. In experiment Nα9, the temperature of the heated gas was lower than 200°C.

The heating effect on the threads was insufficient, and thread unevenness was large as described above. In experiment N (112), the temperature of the heated gas was 500
Since the temperature was higher than 0.degree. C., it caused the threads to stick together and break, making spinning impossible.

(Effect of the invention) According to the invention, at a spinning speed of 5000 m/min or more.

Polyester fibers with extremely high yarn uniformity can be produced industrially under extremely stable operating conditions.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the spinning method of the present invention, and FIG. 2 is an explanatory diagram showing one embodiment of the conventional spinning method. 1: Spinneret, 3: Cylindrical cooling device, 4: Spun yarn.

Claims (1)

[Claims] (1) Melt-spun polyester polymer from a spinneret,
When taking the yarn at a speed of 5,000 m/min or more, a heating cylinder with a length of 5 to 20 cm installed just below the spinneret surface increases the temperature to 2.
00~500℃ heated gas at a wind speed of 0.05~0.8m/
A method for high-speed spinning of polyester fibers, which comprises spraying onto the spun yarn in seconds, and then cooling and solidifying the yarn using a cylindrical cooling device disposed directly below a heating cylinder.