JPS60246807A - Cooling of melt-extruded yarn - Google Patents

Abstract

PURPOSE:The yarn inlet of the cooling chimney is positioned at a specific distance from the spinneret down and cooling air at a specific temperature is forcibly blown from the cooling chimney to effect high-efficienty cooling and solidification of the yarn. CONSTITUTION:The extruded yarn is cooled with pre-cooling air (ar 10-20 deg.C) from the horizontal air blower 2, then introduced into the cooling chimney 3 where the yarn is cooled and solidified with the air lower than -5 deg.C. The cooling air is fed at a position downstream from the spinneret 1 by 0.05XW<1/2>XV<1.39> meter [W is the through-put of the polymer from each nozzle (g/min); V is the first take-up of the yarn (km/min) to effect forced cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cooling and solidifying a melt-spun yarn by blowing cooling air onto it. In particular, the present invention relates to a cooling method that is effective when spinning spun yarn with a large amount of discharge per single hole at high speed.

[Conventional technology]

In recent years, silk spinning technology has been developed to omit the drawing process by spinning thermoplastic synthetic fibers made of polyester, polyamide, etc. at high speeds of 4,000 to 6,000%, thereby completely improving discharge productivity and reducing costs. is becoming common.

In high-speed spinning, as air resistance increases, the tension applied to the yarn increases, resulting in deterioration of yarn properties such as deterioration of yarn strength and elongation characteristics and decreased yarn uniformity. .

Therefore, methods have been proposed to reduce air resistance, or to move the refueling position or focusing position closer to the mouth surface. However, when the oil supply position and focusing position are brought closer to the spinneret surface, the area for cooling the spun yarn becomes shorter, so the conventional method of cooling the yarn using cooling air at 10 to 20 degrees Celsius cannot be used. However, it has not been possible to cool the yarn spun at high speed to a temperature sufficiently higher than the glass transition temperature of the polymer, either by the cross-air cooling method or by the radial-air cooling method. Especially in the case of a large number of yarns (e.g., the discharge amount per single hole is 8% or more), if the yarn temperature is high during oiling or bundling, yarn unevenness and yarn breakage due to contact between yarns will increase, resulting in yarn spinning. Insufficient cooling became a big problem as it deteriorated the performance.

[Problem that the invention seeks to solve]

The present invention improves the drawbacks of these conventional cooling methods and makes cooling more efficient when cooling and solidifying yarns made by spinning a molten polymer by blowing cooling air. The purpose is to make it possible to produce yarn with excellent yarn properties with less yarn breakage and yarn unevenness by increasing the efficiency of this cooling, without increasing the length of the equipment, and with high productivity and high speed. It is intended for different purposes.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention aims to replace at least a part of the cooling with cooling air for cooling and assimilating the melt-spun yarn by blowing strong cold wind of -5°C or less toward the yarn. The distance (L
This is achieved by m).

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic process diagram, and FIG. 2 is a schematic cross-sectional view of a cooling cylinder.

The molten aggregate is spun out from the discharge hole of the spinneret 1 to become a spun yarn Y. Immediately after the spun yarn is discharged, a unidirectional preliminary cold air (
After being pre-cooled at 10 to 20°C), it is then introduced into the cooling cylinder 3, where it is cooled and solidified by strong cold air at -5°C or lower. Next, a lubricant is applied by the oil supply guide 4, and after passing through the first take-up roller 5 and the second take-up roller 6, it is wound up by the winder 1.

The important thread in the present invention is (0,05X J"'F X V "3γ) rn from the discharge hole of the spinneret 1.
(fc ff L, W are the discharge amount (岑) of the single-hole Aori glue 7 combination, and ■ is the yarn speed (＼) when it is first taken off.) As above, the yarn is 0 [Function] The method is to perform strong cooling using a strong cooling means, and to perform the strong cooling by using strong cold air of −5° C. or lower and blowing the strong cold air toward the yarn. If the distance 1.31 (L) from the discharge hole to the yarn population in the cooling tube 3 is shorter than (0.05Xυ1"×V,) m, spinning is performed until the yarn population reaches 30 in the cooling tube where strong cooling is performed. Since the yarn cannot be pre-cooled sufficiently, the spun yarn is strongly cooled while remaining at a high temperature, resulting in yarn unevenness and a decrease in strength and elongation properties due to rapid cooling.

As a means for pre-cooling the yarn before it reaches the cooling tube 3, a cross-wind cooling device as shown in FIG. 1 is preferable. - The cross-air cooling device has a length of 1~1.5ff and a 1% cold air temperature of 10~
The temperature may be about 20°C. As a pre-cooling means, a conventional yarn cooling means such as a pond can be used, and if the pre-cooling is performed over a considerably long length, the pre-cooling can be performed without cooling air. However, Ylli III (rJ) from the discharge hole to the cooling cylinder inlet is (0,5XV]"X V
If the length is F or more than m, the tension of the yarn will be high and unevenness will occur, and the equipment will become long, which is not preferable.

The temperature of the strong cold air must be below -5℃,
If the temperature exceeds 5°C, the yarn cannot be sufficiently cooled, and the object of the present invention cannot be achieved.

The temperature of this strong cold air is preferably -20°C or less. Note that this strong cold air may be air that has been forcibly cooled to the above temperature.

It is preferable that the strong cold air is blown out from the entire outer periphery of the running yarn Y toward the center of the yarn, as shown by the arrow in FIG. On the other hand, when strong cold air is blown from the side as in the case of a cross-wind cooling device, it is not preferable because the running stability of the yarn is lost.

The length of the cooling cylinder 3 is preferably 05 to 3 m. 0
．． If the length is less than 5 m, it is difficult to provide sufficient cooling to the yarn.

On the other hand, if the length exceeds 3 m, the yarn will sway in the cooling cylinder, leading to deterioration in yarn spinning properties.

Moreover, it is preferable that the inner diameter of the cooling cylinder is 5 to 0 mm. If it is less than 5H, mutual interference between yarns occurs at the tube entrance, making yarn unevenness and yarn breakage more likely to occur. On the other hand, if the thickness exceeds 1001M, it is difficult for strong cold air to reach the interior between the yarns, and the single yarn located at the center of the yarns tends to be insufficiently cooled.

As a device for generating strong cold air, a vortex generating type device using compressed air, such as "Portex Cooler°" (manufactured by Portex Corporation, USA), is preferable in terms of equipment.

After being forcedly cooled, the yarn may be spun using a normal yarn spinning method in which it is stretched after the first roller (first take-up roller 5) and then wound without being stretched. The pick-up speed is 4,000
A high-speed spinning method with o'4 or more is preferable in order to obtain yarn with excellent yarn properties with good productivity.

In the method of the present invention, polymers that can be melt-spun are generally used, such as polyester, polyamide, polyethylene, polyester amide, etc., but in particular, polyamides and polyesters, which have a high specific heat and are difficult to cool, can be spun. The method of the present invention is effective for this purpose. Incidentally, these polymers may contain some additives such as matting agents, heat-resistant agents, and light-resistant agents.

〔Effect of the invention〕

By cooling the spun yarn using the method of the present invention, sufficient cooling can be performed without increasing the length required for cooling, resulting in excellent yarn properties with less yarn breakage and yarn unevenness. yarn can be obtained. In addition, sufficient cooling can be achieved even when the amount of polymer discharged per single hole is as high as 3% or more, so the method of the present invention is effective for improving the yarn properties of relatively thick denier yarn. . Since the method of the present invention is fast, sufficient cooling is required.
It is also effective when performing high-speed spinning of '4' or higher.

Furthermore, according to the method of the present invention, the length required for cooling after spinning can be shortened.

(Example (and Comparative Example)) - Example (and Comparative Example) 1 After melting a sulfuric acid nylon hexapolymer with a relative viscosity of 26 at 270°C, from 8 discharge holes of 05 mm φ, 6 ζ per single hole,
It was spun at a discharge rate of .

After pre-cooling this spun yarn using a cross-air cooling device with a length of 100CFB+ under conditions of a cold air temperature of 20℃ and a wind speed of 40~, the spun yarn has a length of 24m1 and an inner diameter of 15mm with an inlet located at a distance of 2m from the discharge hole. It is introduced into a dragon cooling cylinder and strongly cooled, then oiled and taken up to the first take-up roller at 5,500%, and the yarn of 83 denier and 8 filaments is
It was wound at 400%. At this time, the temperature of the strong cold air inside the cooling cylinder was variously changed, and the characteristics of the resulting yarn were evaluated. In addition, for comparison purposes, a case was made in which there was no strong cooling using a cooling cylinder. The results are shown in Table 1.

As can be seen from the results in Table 1, when strong cold air at -5°C or lower is used, cooling is sufficient, so the resulting yarn has small Worcester spots1 and good strength and elongation properties. Met.

- Example (and Comparative Example) 2 The number of discharge holes was 4, the polymer discharge amount was 6 to 4, the length of the cooling tube was 1.2111, and the temperature of the strong cold air was 1.25.
℃, and the distance (L) from the discharge hole to the inlet of the cooling cylinder and the take-up speed (v) were repeated to obtain a 4-filament nylon 6 yarn by repeating the same method as in Example 1. The results are shown in Table 2.

[Brief explanation of the drawing]

FIG. 1 is a process schematic diagram showing one embodiment of the method of the present invention, and FIG. 2 is a schematic cross-sectional view showing one embodiment of the cooling tube used in the method of the present invention. 1: Spinneret with discharge hole 2: Cross wind cooling device 3: Cooling cylinder 4: Oil supply guide 5: First take-up roller (first take-up loan) Y: Spun yarn L: From discharge hole to cooling cylinder population Distance (Municipal Patent Applicant Toshi Co., Ltd. Figure 1)

Claims (3)

[Claims] (1) A yarn made by spinning a molten polymer through a discharge hole,
In the method of cooling and solidifying by blowing cooling air, at least a part of the cooling is performed by strong cooling means that blows strong cold air of −5° C. or lower toward the yarn, and the discharge hole A method for cooling melt-spun yarn, characterized in that the distance (Llll) from the center to the yarn population of the cooling cylinder on which the strong cold air is blown is. (2) The melt spinning method according to claim 1, wherein the yarn after being cooled and solidified has a take-up speed of 4,000'/l or more when first taken off, and a color of at least 4,000'/l. Cooling method for spinning yarn. (3) The method for cooling melt-spun yarn according to claim 1m or 2, wherein the polymer discharge amount is 3 mm or more. (4) The method for cooling molten and spun yarn according to claim 1, 2, or 3, characterized in that the temperature of the strong cold air is 120° C. or less.