JPH05321024A - Method for high-speed spinning of polyester yarn - Google Patents

Abstract

PURPOSE:To spin polyester yarn at high speed industrially, extremely stably and in good handleability by extruding melt of polyester from a spinneret, passing yarn through a heating zone right under the spinneret, cooling and solidifying by a cooler and taking-up the yarn at a high speed under specific conditions. CONSTITUTION:A polyester (e.g. polyethylene terephthalate) is melted at 295 deg.C, subjected to melt spinning from a spinneret satisfying formula I [Q is amount of melt extruded from single hole of spinneret (g/second); A is single hole area (cm<2>) of spinneret (cm<2>)] and formula II [L is circumferential length (cm) of single hole of spinneret] and passed through a heating zone composed of a cylindrical heating column at >=250 deg.C atmosphere temperature installed right under the spinneret. Then the spun yarn is sprayed with cooling air having 20 deg.C and 0.7 m/second blowing speed from a cylindrical cooler, cooled and solidified. The yarn is bundled by a yarn collecting guide as used as an oiling device, taken-up by a godet roll at >=6,000m/minute take-off speed and wound by a high-speed winder to give the objective polyester yarn industrially, extremely stably and in good operation efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed spinning method for polyester fibers, and more particularly to a high-speed spinning method capable of stably producing polyester multifilament yarn for clothing.

[0002]

2. Description of the Prior Art When polyester is melt-spun at a high take-up speed of 5000 m / min or more, mechanical stretching is not required.
It is known that fibers having practically sufficient properties can be obtained, and such a high-speed spinning method is a spinning method that has advantages such as high productivity and simplification of steps and reduction of energy cost. is there.

On the other hand, however, in such a high-speed spinning method, the tension applied to the yarn is large in the spinning process,
There is an operational problem that the thread is frequently cut. As a method of reducing this spinning tension, a method of heating the spun yarn by providing a heating area under the spinneret is usually adopted.In addition, in order to suppress the increase in tension due to air resistance, Attempts have been made to reduce the distance to the location.

However, in these methods, since the high-temperature yarn passes through a short section at a high speed, the yarn is taken up without being cooled sufficiently uniformly. Especially, in the case of a multifilament yarn, the cooling rate between filaments is high. However, there is a problem that the difference between the two becomes large and the yarn becomes inferior in performance.

A factor that causes yarn breakage due to an increase in spinning tension is neck-like deformation in the thinning process, which is a phenomenon peculiar to high-speed spinning at a take-up speed of 5000 m / min or more (Reference Internationale Chemifasertagung in Dornbirn).
(1979), Journal of the Textile Society of Japan, Volume 38, No. 11, p. 499 (1982)
etc). When the deformation rate at this neck-shaped deformation point increases,
The stress concentrated at the deformation point increases, leading to thread cutting. In order to prevent cutting at such a neck point, Japanese Patent Laid-Open No. 1-31
In Japanese Patent No. 4721, a method is proposed in which a neck deformation ratio is specified and spinning is performed at a take-up speed of 9000 m / min or more, but there is no special limitation on spinning conditions for realizing the specified deformation ratio. However, the ordinary spinning method is adopted, and the operability is not substantially improved. Further, there is also a problem that the difference in cooling rate between filaments causes a difference in the position of neck deformation as described above, which increases the fineness unevenness of the taken-up yarn.

Further, in Japanese Patent Application Laid-Open No. 63-282309, 5000
In melt spinning at a take-up speed of m / min or more, it is proposed to improve the filtering material in the spin pack to reduce the frequency of yarn breakage due to stress concentration on foreign substances mixed in the polymer. However, even in this case, no measures have been taken to control tension and neck deformation,
Operability remains a problem.

As described above, in order to carry out the high-speed spinning method, it is necessary to properly control the spinning tension, the spinning conditions are very limited, and it is difficult to carry out a stable operation.

[0008]

DISCLOSURE OF THE INVENTION The present invention has a take-up speed of 6000 m / min or more and is industrially extremely stable with good operability.
It is an object of the present invention to provide a polyester fiber high-speed spinning method capable of producing a polyester fiber.

[0009]

The present invention is intended to solve the above-mentioned problems, and its gist is as follows. The polyester is melt-spun from the spinneret and passed through a heating zone located directly below the spinneret at an ambient temperature of 250 ° C or higher. Then, the yarn is cooled and solidified by a cooling device, and then taken up at a take-up speed of 6000 m / min or more. In the method, formula (a) and
A high-speed spinning method for polyester fiber, which satisfies the requirement (b). (A) 1.4 × 10 ^-2・ Q ≦ A ≦ 5.5 × 10 ^-2・ Q (b) 3.7 ・ A ^1/2 ≤L ≦ 8.9 ・ A ^1/2 Q: Single-hole die discharge rate (g / sec) A: Single hole area of base (cm ² ) L: Perimeter of single hole of base (cm)

The present invention will be described in detail below. Polyethylene terephthalate is generally used as the polyester in the present invention, but a polyester obtained by mixing or copolymerizing the third component, a matting agent, a coloring agent, a stabilizer, and It may contain an electric agent or the like. The degree of polymerization is not particularly limited as long as the fiber-forming property is in a good range, but the present invention is a method particularly suitable for producing polyester multifilament yarn for clothing, and phenol and tetrachloride Concentration 0.5g with solvent equal weight mixture with ethane
/ Dl, relative viscosity measured at a temperature of 25 ° C is preferably about 1.30 to 1.45.

A feature of the present invention is that when melt-spinning is performed at a take-up speed of 6000 m / min or more, the relationship between the single hole area of the spinneret and the discharge amount is defined, so that the yarn in the heating region and the cooling region is defined. It is intended to improve the heat transfer efficiency of the yarn in the spinning process by controlling the passage time of the spinneret, defining the single hole perimeter of the spinneret, and controlling the surface area of the spun yarn. By effective heat exchange in the heating and cooling zones,
High speed spinning is possible with proper tension. That is,
The yarn is sufficiently heated in the heating zone, and the tension applied to the yarn in the initial stage after spinning is suppressed. By maintaining the yarn at high temperature and low tension, the neck deformation point is located lower than the conventional method, and the neck deformation occurs at the position where the thinning progresses, so the deformation rate at the neck point is small and The stress concentrated at the points is reduced and the frequency of thread breaks is significantly reduced. Further, in the cooling region, since there is a sufficient cooling effect, uniform cooling is performed, and stable spinning is possible without deterioration in yarn quality due to insufficient cooling.

Single hole area A of the die used in the present invention
Needs to be within a range that satisfies the condition of the above equation (a) with respect to the single hole discharge amount Q. When the single hole area is within this range, when spinning at a take-up speed of 6000 m / min or more, the yarn passes through the heating zone and the cooling zone in a running time suitable for heat exchange. If the area of a single hole is smaller than the above range, the discharge linear velocity is too fast, so the time to pass through the heating zone and the cooling zone is shortened, sufficient heat is not transferred, and the yarn is cut or the yarn is cooled. There will be a shortage. On the other hand, if the single hole area is larger than the above range, the draft rate represented by the ratio of the take-up speed and the discharge linear velocity becomes too large, so that the deformation rate in the spinning process becomes large and the yarn is easily cut. Become.

Further, the single hole perimeter L of the die needs to be within a range satisfying the condition of the above formula (B) with respect to the single hole area A. When the perimeter of the single hole is within this range, the heat exchange efficiency of the spun single yarn in the heating region and the cooling region is good, and further, the single yarn is formed so that the wound yarn has a practical shape. The surface area is controlled. If the perimeter of the single hole is smaller than the above range, the surface area of the single yarn is small and heat exchange cannot be performed efficiently. On the other hand, if the perimeter of the single hole is larger than the above range, there are problems that the cross-sectional shape of the single yarn becomes too complicated, spinning is difficult, or the yarn does not reach the practical level in strength.

The shape of the holes in the spinneret is defined by the above formula (a),
It is not particularly limited as long as it can satisfy (b), but Y-type, J-type and the like are preferable because stable spinning is possible. The arrangement of holes varies depending on the number of filaments, but if it is about 10 to 50 filaments used for normal clothing, it is an arrangement with little difference in heat transfer between filaments such as single circle arrangement and double circle arrangement. Is preferred.

The ambient temperature of the heating area provided directly below the base is
It needs to be 250 ℃ or higher. If the ambient temperature is lower than 250 ° C, the yarn will not be heated sufficiently and spinning will be difficult.
The length of the heating zone is preferably about 5 to 20 cm. If the length of the heating zone is shorter than this range, a sufficient heating effect of the yarn cannot be obtained, and the spinning yarn becomes difficult due to a rapid temperature decrease. On the other hand, if the length of the heating zone is longer than this range,
In order to complete the cooling of the yarn, it is necessary to increase the distance to the take-up position of the yarn, which leads to an increase in spinning tension and makes spinning difficult.

The heating method in the heating area includes a method of disposing a cylindrical heating element, a method of blowing a heating gas to the yarn, and the like, but it is a method of keeping the atmosphere temperature in the heating area uniform. However, it is not particularly limited.

[0017]

EXAMPLES Next, the present invention will be specifically described by way of examples. In addition, the measuring method of the characteristic value in this invention is as follows. (a) Tensile strength Using Autograph DSS-500 manufactured by Shimadzu Corporation, sample length 30
cm, tensile speed 30 cm / min. (b) Initial Young's modulus The Young's modulus was calculated from the initial slope of the load-stretch curve obtained during the measurement of strength and elongation. (c) Fineness Unevenness It was measured by a half-inert test using a Wooster yarn unevenness measuring device manufactured by Zellvega.

EXAMPLE A polyethylene terephthalate chip having a relative viscosity of 1.38 was melted at a melting temperature of 295 ° C., and then passed through a spinneret having 24 holes, a double circle of holes and having the shape, area and circumference shown in Table 1. Then, through a spinning tube having a discharge amount shown in Table 1, placed directly under the spinneret, and passing through a cylindrical heating tube having a length of 10 cm set so that the atmospheric temperature in the tube becomes the temperature shown in Table 1, immediately below the heating tube. A length of 30 with a heat insulating plate placed 20 cm below the base
After cooling the spinning yarn by blowing a cooling air with a temperature of 20 ° C and a blowing speed of 0.7 m / sec from a cylindrical cooling device of cm, the yarn bundle also functions as an oil supply device placed 120 cm below the spinneret. Focused by the guide. The bundled yarn is taken up by the first godet roller having the surface speed shown in Table 1, and then continuously wound by the high speed take-up device through the second godet roller without stretching to obtain a 72d / 24f multifilament yarn. It was

Table 1 shows the spinning conditions when spinning was performed under each condition. The spinning condition was evaluated according to the following three stages depending on the cutting condition when winding 10 kg of yarn. ◯: No cutting, Δ: 1 to 3 single yarn breaks, X: frequent cutting.

[0020]

[Table 1]

In No. 1 and No. 2 which are examples of the present invention, stable spinning was possible without the yarn being cut. On the other hand, No. 3 where the area A of the single hole of the die is smaller than the range of formula (a)
The discharge linear velocity was high and the cutting occurred frequently, and in No. 5 which was larger than the range of the formula (a), the draft rate was large and single yarn breakage occurred. Further, in No. 6 in which the single hole perimeter L of the die is shorter than the range of the formula (b), heating and cooling efficiency is poor, and single yarn breakage occurs. Was large and spinning was impossible. Further, in No. 4 in which the temperature in the heating region was lower than the range of the present invention, the tension was high and spinning was impossible.

Table 2 shows the results of measuring the physical properties of the yarns wound under the conditions of Nos. 1, 2, 5 and 6.

[0023]

[Table 2]

The yarns obtained in No. 1 and No. 2, which are the examples of the present invention, had physical properties that were not problematic as fibers for clothing, but No. outside the range of the present invention. The yarns obtained in No. 5 and No. 6 have large fineness unevenness,
It was unsuitable as a fiber for clothing.

[0025]

Industrial Applicability According to the present invention, polyester fibers can be industrially manufactured in a very stable operation state at a take-up speed of 6000 m / min or more.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Ide, 23 Uji Kozakura, Uji, Kyoto Prefecture Unitika Central Research Institute (72) Inventor, Ryo Kanaki 23, Uji Kozakura, Uji City, Kyoto Unitika Central Research Company In-house

Claims (1)

[Claims] 1. A polyester is melt-spun from a spinneret and allowed to pass through a heating zone having an atmospheric temperature of 250 ° C. or higher arranged immediately below the spinneret, and then the yarn is cooled and solidified by a cooling device, and then 6000 m / min or more. A method for high-speed spinning of polyester fibers, wherein the methods (1) and (2) are satisfied in the method for drawing at a drawing speed of 1. (A) 1.4 × 10 ^-2・ Q ≦ A ≦ 5.5 × 10 ^-2・ Q (b) 3.7 ・ A ^1/2 ≤L ≦ 8.9 ・ A ^1/2 Q: Single-hole die discharge rate (g / sec) A: Single hole area of base (cm ² ) L: Perimeter of single hole of base (cm)