JPS61289117A - Production of hollow polyester fiber - Google Patents

Abstract

PURPOSE:To provide the titled fiber having an essentially annular cross-section, by using a spinneret having a plurality of arc slits directing the concave side toward the center of the nozzle and melt-spinning a polyester through the spinneret under specific condition. CONSTITUTION:A polyester is spun at a spinning temperature of 275-295 deg.C through a spinneret composed of 2-6 arch slits directing the concave side toward the center of the nozzle (preferably, the gap Y between the slits is 0.07-0.15mm, the width W of the slit is 0.06-0.12mm, the radius of the inscribed circle R is 0.35-1.00mm and the depth of the slit is 0.25-0.70mm). The position of the spinneret is between 10cm below and 20cm above the bottom liquid level A in the heating thermal medium chamber 2 of a spinning machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing hollow polyester fibers. More specifically, the present invention relates to a method for stably producing hollow polyester fibers having a large hollowness ratio, a substantially annular cross section, and a single yarn denier of 1 to 10 d.

[Prior art and its problems]

Conventionally, the method for spinning hollow fibers was
A method of manufacturing by inhaling air or inert gas from the center of a 10-karat hole, as shown in the example of Publication No. 8988.
However, the spinneret is complicated and expensive, and furthermore, it is difficult to control the area around the spinneret during manufacturing, making stable production difficult.

On the other hand, research has also been conducted on making hollow fibers using a spinneret with relatively simple specifications, as seen in the example of JP-A No. 54-15023, but it has not been possible to make hollow fibers until the molten polymer discharged from each slit is cooled and solidified. This method has the drawback that it is difficult to obtain a hollow fiber having a substantially annular cross section and a large hollowness ratio.

[Purpose of the invention]

The object of the present invention is to improve the shortcomings of the prior art, and to produce hollow polyester fibers having a substantially circular cross section with a large hollowness ratio and a single denier of 1 to 10 d, i. - It provides a stable manufacturing method.

[Structure of the invention]

The object of the invention described above is to use a hollow fiber spinneret whose spinneret hole is composed of two or more and six or less arc-shaped slits having a concave portion toward the center of the spinneret hole, and to reduce the spinning temperature from 275°C to 295°C. Hollow polyester fiber characterized in that, when spinning to obtain a hollow fiber as described below, the attachment position of the spinneret is within the range of 10 JEI below to 20 JEI above with respect to the bottom liquid level of the heating medium chamber of the spinning machine. This can be achieved by the manufacturing method.

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

FIG. 1 is a longitudinal sectional view showing an example of a state in which a spinneret is attached to a spinning machine according to the present invention. In FIG. 1, 1 is a spinning machine, 2 is a heating heat medium chamber, 3 is a cap unit, 4 is a 7-lunge for fixing the cap unit position, 5 is an F material layer, 6 is a dispersion plate, 7 is a cap, 8 9 is a polymer passage, and 9 is a heat-insulating lid.

After the molten polymer is metered by a polymer pump (not shown), it passes through a polymer passage 8t, is filtered through a door material layer 5 to remove foreign substances, is discharged from a spinneret 7, and then passes through a chimney ( While being cooled and solidified with cold air (not shown), the yarn is wound up at a predetermined spinning speed to become a hollow polyester undrawn yarn.

In the present invention, it is important that the attachment position of the spinneret be in the range from the lower side 101M to the upper side 201111 with respect to the bottom liquid level A of the heating heat medium chamber 2 of the spinning machine.

If the mounting position of the cap 7 is more than 10 degrees below the bottom liquid level A of the heating medium on the discharge surface of the cap, the quenching effect of the polymer discharged from each slit of the cap becomes large and the adhesion becomes insufficient. , so-called puncture phenomenon of hollow fibers will occur, and furthermore, the molecular orientation of the polymer will become insufficient, and the strength and elongation level of the obtained hollow fibers will decrease.
Because the so-called weak thread phenomenon occurs, the nozzle discharge surface is located at a lower level 1 with respect to the bottom liquid level A of the heating heat medium chamber 2 of the spinning machine.
On the other hand, if the discharge surface of the nozzle is deeper than 20 degrees above, the hollow fiber puncture phenomenon and the occurrence of weak fibers will disappear, but it will take time for the discharged polymer to be cooled by the cold air of the chimney. As the time becomes longer, the flow deformation time of the polymer becomes longer, the hollowness of the hollow fiber decreases, and the desired hollow fiber with a large hollowness cannot be obtained. It must be below 201EI above the liquid level.
In the present invention, a hollow fiber cap whose cap hole is composed of two or more and six or less arc-shaped slits each having a concave portion toward the center of the cap hole is defined as a hollow fiber cap as shown in FIG. As described above, the shape of each slit substantially consists of a part of the circumference. FIG. 3 is a longitudinal sectional view taken along line XX in FIG. 2. The distance Y between each slit is 0.07~Q, 151EI
.

The width W of the slit is 0.06 to 0.121 m, and the radius R of the inscribed circle formed by each slit is 0.35 to 1.0
010+, slit depth L is 0.25 to 0.7011
A cap that is preferably used is preferably used.

In the present invention, spinning is performed at a spinning temperature of 275°C or higher and 295°C or lower. Specifically, the temperature of the spindle during spinning is 275
Control the temperature at a constant temperature within the range of ℃ to 295℃.

If the spinning temperature is below 280°C, the orientation of the polymer molecules during the process of discharging the molten polymer and solidifying it by cooling becomes insufficient, resulting in a so-called weak fiber phenomenon in which the strength and elongation level of the resulting hollow fibers decreases. On the other hand,
The temperature will exceed 295℃ and “bhact=p”
°"゛"°゛°""1.6+'t"ilo:l&+9A
Af? ih &< a, b*i, i+ The spinning temperature needs to be 275°C or less. 1□,: 1゜, Next, a chimney for cooling the discharged polymer thread 1
Part of the surface is 1,000 muni, and the temperature is 10 to 25.
1) If J ℃ and wind speed satisfy the following formula (4),
Pi 1゜The effect of the present invention becomes even more remarkable and desirable.
:! , [°゛1n 0
:...) h N is the number of cap holes (number of single threads) 4.
ゞ1 ■ is the wind speed of cooling air (m/m1n)
・1゜[J, The hollow polyester fiber of the present invention is polyester □
:, ' Can be widely applied to polymers. For example: Paterephthalic acid is the main dibasic acid, and the main glycol is ethylene glycol matahan clohexanedimethanol, or ethylene oxybenzoate, giving high contractility. Copolymerization of 3 to 15 moles of a third component such as sulfuric acid, sebacic acid, phthalic acid, isophthalic acid, etc. and polyethylene oxide, polypropylene oxide, polyethylene glycol, etc. for the purpose of imparting dyeability, etc. Sodium m-phenolsulfonate, sodium m (β-oxyethoxy)benzenesulfonate, sodium 3,5-dicarbomethoxybenzenesulfonate, dimethyl-5-sodium sulfoisophthalate, bis(β-hydroxyethyl)-5- sodium, inphthalate,
It may be copolymerized with a third component t-1 to 10 molar ratio, or it may contain 0 to 5% titanium oxide for the purpose of matting effect, improving thread-spinning effect, etc. Good too.

〔Effect of the invention〕

By employing the above configuration, the present invention can stably produce hollow polyester fibers having a large hollowness ratio, a substantially annular cross section, and a single yarn denier of 1 to 10 d.

The present invention will be explained below using examples.

Example 1 A cap is composed of three identical arc-shaped slits as shown in Fig. 2, and the interval between each slit is A== 0.10 w.
g, relationship L/W between slit depth L and slit width W:
6. The relationship between the radius R of the inscribed circle formed by each slit and the width W of the slit is R/W = 6.5, and using a cap with 24 holes, the intrinsic viscosity W 0.65 (25 ° C (measured in phenol), polyester chips with a melting point of 256°C were discharged at a rate of 45.0 g for 7 minutes, the spinneret temperature was 285°C, the spinning speed was 1500 m/min, and the cooling air temperature was 19.
℃, the wind speed of the cooling air was 55 m/min, and the undrawn yarn obtained by variously changing the attachment position of the spinneret relative to the bottom liquid level of the heating medium chamber of the spinning machine was drawn to 3.0 times by a conventional method. 100
The drawn yarn had a denier of 24 filaments, and the results shown in Table 1 were obtained.

FIG. 4 is a cross-sectional view showing an example of the obtained hollow fiber,
Sl indicates a cross-sectional portion of the fiber, and S2 indicates a hollow portion.

Note that the definition of hollowness ratio is as follows.

Table 1 1) The bottom liquid level of the heating medium of the spinning machine is set to zero, and the lower part is indicated as negative and the upper part is indicated as positive.9°◎...Extremely good○... ...Good × ...Bad In Table 1, Experiments 7f11 and 6 are comparative examples for clarifying the effects of the present invention.

In Experiments A3 and 4, hollow fibers with good cross-sectional shape, hollowness ratio, and strength/elongation level were obtained. In A2, the strength and elongation level tended to decrease slightly, but it was at a level that poses no problem in practical use, whereas in A1, puncture-like single yarns occurred.
The strength and elongation level was also low, making it a weak yarn. On the other hand, the hollowness ratio of No. 45 was significantly reduced, but it was within the range of the hollow fiber targeted by the present invention, whereas the hollowness ratio of Muro reached the level of the hollow fiber targeted by the present invention. It was something I wouldn't do.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a state in which a spinneret is attached to a spinning machine according to the present invention. FIG. 2 is a plan view showing an example of the shape of the cap slit of the cap used in the present invention, and FIG. 3 is a longitudinal sectional view taken along the line XX in FIG. FIG. 4 is a cross-sectional view showing an example of a medium heather yarn obtained by the present invention. 1: Spinning machine 2: Heating heat medium chamber 3: Cap unit 4: Seven lunges 5: P material layer 6: Dispersion plate 7: Cap 8: Polymer passage 9: Heat insulation lid A: Bottom liquid level Y: Spacing between each slit Width of W slit L Depth of slit R: Radius of the inscribed circle formed by each slit

Claims (1)

[Claims] Hollow fibers are produced by spinning at a spinning temperature of 275° C. or higher and 295° C. or lower using a hollow fiber spindle whose spindle hole is composed of 2 or more and 6 or less arc-shaped slits having a concave portion toward the center of the spinneret hole. A method for producing hollow polyester fibers, characterized in that the attachment position of the spinneret is set within a range of 10 mm below to 20 mm above the bottom liquid level of a heating medium chamber of a spinning machine.