JPH0617304A - Melt-spinning apparatus for ultrafine fiber - Google Patents

Abstract

PURPOSE:To provide a spinning apparatus capable of stably producing an ultrafine fiber having a low denier unevenness at a high spinning speed while suppressing the deposition of foreign materials on the spinneret surface. CONSTITUTION:A filament (y) flows down into a cooling chamber 13 through a retarded cooling zone 6 surrounded by a heater 3 and a guide shutter 8 immediately below a spinneret and an ascending air flow is generated by the entrained air flow caused by the downward motion of the filament. The ascending air flow moves upward along the shutter 8 and flows from the upper opening 9 of the shutter along the lower face of the spinneret 2 to prevent the turbulent flow and to keep a high temperature immediately below the spinneret. The denier unevenness and spinnability can be improved by this process. The polymer decomposition gas generated immediately below the spinneret face does not retain in the above space and the spinneret face is constantly covered with the ascending air flow to suppress the deposition and growth of foreign materials and decrease the frequency of end breakage, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for melt-spinning thermoplastic synthetic fibers of ultrafine denier such as polyamide and polyester, and more particularly to heating under the spinneret surface and suppressing gas retention on the spinneret surface to prevent foreign matter from forming on the spinneret surface. The present invention relates to a melt-spinning apparatus in which the occurrence of adherence is reduced and the spinnability of ultrafine denier is improved.

[0002]

2. Description of the Related Art Generally, when a thermoplastic polymer such as polyamide or polyester is melt-spun, a gas such as a sublimable substance such as an oligomer produced by decomposition of a polymer spun from a spinneret is discharged. This gas easily stays under the spinneret, and when it touches the spinneret surface, it becomes solid and adheres and accumulates as foreign matter on the spinneret surface. In particular, when the foreign matter attached to the periphery of the die hole grows large, the yarn discharged from the die hole comes into contact with the yarn, causing yarn breakage and deteriorating the process condition.

Various methods have been attempted as a method for spinning the decomposition gas under the spinneret from adhering to the spinneret surface. However, the spinneret pack is provided with an opening penetrating upward from the surface having the spinneret. There has been proposed a method for discharging (Japanese Patent Laid-Open No. 3-45975).

In addition, in order to prevent the gas under the spinneret from staying on the spinneret surface, there are some which are provided with a guide shutter between the spinneret, which narrows in a tapered shape so as to surround the spun yarn from the shutter toward the spinneret. (Kaihei 3-45975).

However, when the ultrafine polyester fiber is manufactured by such a method, there is a problem that the cooling immediately below the multi-hole spinneret is delayed and denier unevenness (u%) and deterioration of spinning quality are likely to occur.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is directed to high-speed spinning of ultrafine fibers, particularly to thermoplastic fibers taken up at a spinning speed of 2800 m / min or more. An object of the present invention is to provide an apparatus capable of stably obtaining an excellent quality product with less thermal deterioration and adhesion of foreign matter to the spinneret surface and less denier unevenness in melt spinning.

[0007]

That is, the present invention is a melt-spinning apparatus for thermoplastic ultrafine fibers having a single yarn fineness of 0.8 denier or less and a single yarn number of 70 or more.
A heater with a thickness of -10 mm, a heat-retaining part, and a shutter are provided in this order, the distance from the spinneret surface to the shutter is 30 to 50 mm, and the upper part is small so as to surround the spun yarn from the shutter to the spinneret. An ultrafine melt-spinning apparatus having a tapered cylinder.

[0008]

Function: The spun yarn flows down from the tapered guide shutter in the spinning cylinder at a high speed, so that an accompanying flow is generated. Along with this, an ascending flow is generated along the tapered surface of the guide shutter. The airflow is a circulating airflow flowing from the upper opening of the guide shutter along the lower surface of the base. Therefore, the effect of preventing turbulent flow immediately below the spinneret and the heat retaining effect are exhibited, and the denier unevenness and the spinnability are improved. Also, the polymer decomposition gas generated just below the die surface does not stay in the space,
Since the surface of the mouthpiece is constantly covered with an upward airflow, adhesion and growth of foreign matters are suppressed, and the occurrence of troubles such as yarn breakage is reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
FIG. 2 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is A- of FIG.
FIG. 3 is a plan view taken along the arrow A, and FIG. 3 is a plan view taken along the line BB in FIG.

In the figure, reference numeral 1 denotes a spin pack mounted on a spin block 14, which has a spinneret 2 for discharging a plurality of molten polymers. 3 is a heater for preventing thermal deterioration due to high temperature melting of ultrafine fibers and for improving spinnability by heating directly under the spinneret, and a rectangular yarn corresponding to the six spinnerets 2 in the center thereof. Article passage 3a
Are formed and heated to an atmosphere of 250 to 350 ° C.

[0011] Reference numeral 4 prevents the yarn cooling air from the spinning cylinder 10 from rising non-uniformly in the direction of the spinneret 2 and prevents the deterioration of denier unevenness immediately below the multi-hole spinneret. With a shutter set to a relatively short position of 30 to 50 mm, it has a rectangular yarn passage port 5 corresponding to the six spinnerets 2 so that it can be divided at the center so that it can be pulled out to the left and right. Has been done.

Reference numeral 7 is a heat retaining block for forming the relatively short delay cooling section 6. Reference numeral 8 denotes a guide shutter which is provided around the yarn passing port 5 of the shutter 4 so as to surround and surround the yarn passing port 5 in a tapered shape. The cross-sectional area of the guide shutter 8 is gradually reduced and extended, and the upper opening 9 is located near the spinning pack 1. is doing. The distance between the opening 8 and the spinning pack 1 is usually about 5 to 10 mm. The upper opening 9 is sized so that the length of the short side is slightly larger than that of the spinneret 2 and the length of the long side is slightly longer than the positions of the spinnerets 2 at both ends.

Reference numeral 11 denotes an outlet for cooling air, which is located above the spinning cylinder 10, and has an outlet (face) 12 and a cooling chamber 13.

In such an apparatus, the yarn y discharged from the spinneret 2 flows down into the cooling chamber 13 via the relatively short delay cooling section 6 surrounded by the heater 3 and the guide shutter 8 immediately below the spinneret. It is cooled and solidified by the cooling air blown from the air outlet 12.

In this case, since the yarn is extremely fine and has a large number of holes, there is a problem that the spinnability is deteriorated when the atmosphere temperature directly under the spinneret is low, and the denier unevenness is deteriorated when the uniform cooling under the spinneret is too slow. However, in the present invention, the ambient temperature of 10 to 20 mm below the spinneret is maintained at 220 ° C. or higher, and in order not to delay the cooling of the yarn, a guide shutter is attached to 30 to 50 mm below the spinneret to perform uniform cooling just below the shutter.

At this time, since the yarn flows down at a high speed, an accompanying flow is generated, and as a result, an upflow is generated as shown in FIG. This air flow has a tapered guide shutter 8
Along the lower surface of the mouthpiece 2 from the upper opening 9 of the guide shutter 8 to generate a circulating air flow in the space immediately below the mouthpiece surface, which prevents turbulence immediately below the mouthpiece and retains heat. Denier spots and spinnability are improved. Further, the polymer decomposition gas generated just below the die surface does not stay in the space, and the die surface is constantly covered with an ascending air current, which significantly improves foreign matter adhesion and growth.
Trouble such as yarn breakage is reduced.

The above-described effects of the present invention are more effective in high-speed spinning at a spinning speed of 2800 m / or higher, and the higher the speed is.

[0018]

As described above, according to the present invention, the spinnability and denier unevenness (u%) of the ultrafine yarns coming out from the spinneret are improved and the yarn breakage during high speed spinning is reduced.
It has a remarkable effect that it is possible to stably obtain a product of excellent quality.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view taken along the line AA of FIG.

FIG. 3 is a plan view taken along the line BB of FIG.

[Explanation of symbols]

 1 Spinning Pack 2 Spinneret 3 Heater 4 Shutter 6 Delayed Cooling Section 7 Heat Keeping Block 8 Guide Shutter 10 Spinning Tube 11 Cooling Air Outlet

Claims (1)

[Claims] 1. A melt spinning apparatus for thermoplastic ultrafine fibers having a single yarn fineness of 0.8 denier or less and a single yarn number of 70 or more,
A heater with a thickness of 5 to 10 mm, a heat retaining portion and a shutter are provided in this order directly below the spinneret pack, the distance between the spinneret surface and the shutter is 30 to 50 mm, and the spun yarn is surrounded from the shutter toward the spinneret. An ultrafine melt-spinning apparatus, in which a tapered cylinder having a small upper portion is arranged as described above.