JPH10273813A - Spinneret with H-shaped slit - Google Patents

Abstract

(57) Abstract: A spinneret for use in the production of synthetic fibers having a special cross-sectional shape suitable for clothing, and provides a spinneret having an H-shaped slit hole. SOLUTION: In a H-shaped spinneret comprising an opposing slit and a slit joining the opposing slits, each end of the opposing slit has a circular shape,
The diameter of the circular hole is R (mm), the average linear length of the opposing slits is b (mm), the length of the slit joining the opposing slits is a (mm), and the slit width is c (m).
m) An H-shaped slit spinneret satisfying the following formulas (1) to (3) at the same time when the bending angle of the opposed slit is θ. 2.6 ≦ b / a ≦ 4.0 (1) 1.2 ≦ R / c ≦ 2.0 (2) 80 ° ≦ θ ≦ 87 ° (3)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spinneret used for producing a synthetic fiber having a special sectional shape suitable for clothing. More specifically, the present invention relates to a spinneret having an H-shaped slit hole.

[0002]

2. Description of the Related Art Synthetic fibers such as polyester and polyamide are widely used as raw materials for woven and knitted fabrics. In recent years, many synthetic fiber products having a special cross-sectional shape have been marketed. For example, in the field where gloss is required, it can be obtained by using a T-shaped slit spinneret or a Y-shaped slit spinneret.
In a field requiring light weight and heat retention, a spinneret having a hollow-shaped slit may be used. Thus, by changing the shape of the spinneret, it is possible to obtain a fiber having a desired cross-sectional shape. However, a fiber having an H-shaped cross section may be a spinneret having H-shaped slit holes. The spinneret having an H-shaped slit hole is disclosed in JP-A-56-37309 and JP-A-3-234.
Although disclosed in Japanese Patent Application Laid-Open No. 844, the tip of the slit hole has an acute angle, and "smear of the die" during spinning is likely to occur. This is because the spinneret is exposed to a high temperature for a long period of time, and during spinning, a part of the molten polymer, a low polymer in the polymer or a gel-like substance due to thermal denaturation (decomposition, generation) is discharged from the spinneret. Adheres to the outer edge of the outlet of the pores on the side, this is the heat,
Under the influence of oxygen in the air, it accumulates while changing in a complicated manner and becomes "stained die". With the elapse of spinning time, the amount of "stained die" increases, and an abnormally shaped H-section fiber can be obtained. Finally, cutting of the filament occurs, which is a problem. Further, in the above-described base, since the opposed slits of the H-shaped slit holes are linear, the cross section of the obtained fiber has a cross-sectional shape opened to the outside, and the fiber is split (fiber fission) at the time of spinning or high-order processing. Is easy to occur.

[0003] Japanese Patent Application Laid-Open No. 7-173709 discloses that
A spinneret having an H-shaped slit hole having a bulge portion and a constriction portion is disclosed. However, since a large number of bulge portions are provided at a slit joint portion and the like, the production cost of the die increases, and the area of the die hole is increased. When a multifilament yarn for clothing with a small discharge amount is produced, it is difficult to obtain a stable cross-sectional shape. Further, since the opposing slits of the H-shaped slit holes are linear, the cross section of the obtained fiber has a cross-sectional shape in which the opposing slit portions are opened outward,
Splitting (fiber cracking) is likely to occur during spinning or high-order processing.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art. The dirt on the base is suppressed by forming the tip of the slit hole into a circular shape, and the bending angle of the opposed slit portion is reduced. To 80 ° to 87 °, H
The aim is to provide a spinneret capable of improving the stable productivity of the cross-sectional shape of the Y-shaped cross-section yarn, preventing splitting (fiber cracking) during yarn making, and preventing splitting during high-order processing. is there.

[0005]

That is, in an H-shaped spinneret comprising an opposing slit and a slit joining the opposing slits, each end of the opposing slit has a circular shape, and Of the circular hole of R (m
m), the average linear length of the opposing slits is b (mm),
Let the length of the slit joining the opposing slits be a (m
m), the slit width is c (mm), and the bending angle of the opposed slit is θ, which is achieved by the H-shaped slit spinneret, which simultaneously satisfies the following expressions (1) to (3). be able to.

2.6 ≦ b / a ≦ 4.0 (1) 1.2 ≦ R / c ≦ 2.0 (2) 80 ° ≦ θ ≦ 87 ° (3)

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A spinneret according to the present invention is shown in FIG.
As shown in (1), the cross-sectional shape is formed of an H-shaped slit hole, and the tip of the slit is circular. If the tip of the slit is not circular, the above-mentioned "stain on the die" occurs, i.e., the yarn comes into contact with the dirt such as a gel-like substance attached to the discharge side of the spinneret, causing a so-called "pickle phenomenon" and yarn breakage. Therefore, stable production is difficult.

The symbols a, b, c, θ, and R used below will be described with reference to FIG. The length of the slit joining the opposing slits is a (mm), and a is the length including the slit width c of the opposing slit. The average straight line length b (mm) of the opposed slits, and b is the average length of the straight line connecting both ends of each opposed slit. Set the slit width to c (m
m), the angle θ (°) between the opposing slit and the joining slit, and the diameter R (mm) of the circular circumscribed circle at each end of the opposing slit.

The relationship between a and b needs to be in the range of 2.6 ≦ b / a ≦ 4.0. If b / a is less than 2.6, the lengths of a and b are too short to obtain a normal H-shaped cross-section yarn as shown in FIG. When b / a exceeds 4.0, the yarn becomes a long H-shaped cross-section yarn, and the yarn-yarn abrasion of the drawn yarn becomes poor.
There is a problem that splitting (fiber cracking) is likely to occur in high-order processing. Therefore, b / a = 2.6 to 4.0 is required,
The range of 2.7 to 3.9 is preferred. If b is too short or too long, not only cannot a normal stable H-shaped cross-section yarn be obtained, but also the resulting fibers have poor gloss and texture.
Further, a is 0.46 in consideration of the precision in manufacturing the base.
mm ± 0.01 mm is preferable.

The relationship between the diameter R of the circular hole at the tip end of the slit and the slit width c must satisfy 1.2 ≦ R / c ≦ 2.0. The diameter R of the circular hole can be arbitrarily designed. However, if the diameter R of the circular hole at the tip of the slit exceeds 2.0 times the slit width c, the flow velocity difference between the polymer in the circular portion and the polymer in the slit becomes large, and the discharge unevenness is increased. Occurs and thread spots worsen. On the other hand, if R / c is smaller than 1.2, the effect of suppressing "base stain" is lost, which is not preferable. Therefore, the circular hole diameter R at the tip of the slit is
And the slit width c need to satisfy 1.2 ≦ R / c ≦ 2.0. Preferably, 1.3 ≦ R / c ≦ 1.
9 is in the range. Although the slit width c can be set arbitrarily, a multifilament yarn that can be provided for clothing is obtained, and the slit width c is set to 0.07 ± 0.
005 mm is preferable.

Further, it is necessary to set θ to 80 ° to 87 °. If the angle θ is less than 80 °, the interval (d) between the slit end portions is too small, so that the polymers discharged from the slit holes are joined to each other so that a normal cross-sectional shape cannot be obtained, and yarn breakage occurs and winding takes place. Impossible. When θ exceeds 87 °, the cross-sectional shape of the obtained fiber becomes a special cross-section in which the H-shape opens outward as shown in FIG. Fibers having this special cross section are liable to cause splitting (fiber cracking) at the time of spinning, particularly at the time of drawing, and also cause troubles such as splitting (fiber cracking) at higher processing, which is not preferable. Therefore, when θ is 80 °
It is necessary to set it to 87 °, and it is preferable to set it to 81 ° to 86 °.

In the present invention, the single-denier is 0.5 d.
~ 10d, more preferably 1.5d ~
6d.

The spinneret of the present invention may be any thermoplastic polymer, for example, polyester, polyamide and the like, and polyester terephthalate is particularly preferred.

[0014]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. In addition, the measured value in an Example was measured by the following method.

[Thread spot] A commercially available Uster Ev
Enness Tester (manufactured by Keiki Kogyo Co., Ltd.)
It was used. The measurement slot to be used was selected based on the total denier of the yarn, and the measurement was performed for 1 minute while running at a yarn speed of 200 m / min. Pass in this application is less than 0.5%. [Stain on the cap] Using a long-focal microscope manufactured by CARL ZEISS (Germany), dirt on the cap slit hole was spun with a lens approximately 30 cm to 100 times below the spinneret.
Observations were made every 48 hours. Pass / fail was determined based on the condition of the stain 48 hours after the start of spinning. Grade 1 (pass) No stain 2nd grade (pass) 3rd grade (fail) 3rd grade 4th grade (fail) Dirty [Thread-yarn] Abrasion] (Used as an evaluation method for splitting (fiber cracking)) The number of times the yarn was cut by a rubbing tester manufactured by Toyo Seiki Co., Ltd. was measured to evaluate the yarn-yarn wear. Measurement condition is 100
Stroke times / minute, measurement weight 0.2 g / d. It was determined by the number of cuts. Pass in this application is first grade. Class 1: 800 or more cuts Second: Less than 800 cuts Example 1 a = 0.46 mm, b = 1.40 mm, c = shown in FIG.
0.07 mm, θ = 85 °, slit tip circular hole diameter R =
Using an H-shaped spinneret (diameter 100 mm, thickness 20 mm) having 0.12 mm and 36 discharge holes and a spinneret shown in FIG.
A polyester chip having an intrinsic viscosity of 0.65 and a titanium oxide content of 0.025% by weight is melt-spun at 290 ° C., and after cooling, 0.8% of a spinning oil agent is applied and wound at a spinning speed of 1500 m / min.
An undrawn yarn of 30D-36f was obtained. The obtained undrawn yarn was drawn under ordinary drawing conditions to obtain a drawn yarn of 75D-36f (2d). Very stable results were obtained with almost no yarn breakage during spinning. The yarn spots of the multifilament obtained at this time were also good. The cross-sectional shape was a stable H-type as shown in FIG. Further, stains on the die at each spinning time were observed with a long-focal microscope, and the results are shown in Table 1.

[0016]

[Table 1] Experiment No. In Nos. 1, 3, and 5, no stain on the base was generated, and no breakage of the spun yarn was generated. In addition, extremely stable results were obtained without any problem in spots of the obtained multifilament yarn.

Experiment No. In Nos. 2, 4, and 6, the spun yarn breaks and the stain on the die increases in proportion to the elapse of the spinning time. In addition, the yarn spots of the multifilament yarn also became worse.

Example 2 The ratio of b / a was changed using the same base as in Example 1. Yarn was formed in the same manner as in Example 1 to obtain a 75D-36f drawn yarn. The yarn-yarn abrasion property of the drawn yarn was evaluated, and the results are summarized in Table 2. When b / a is less than 2.6, a fiber having a normal cross-sectional shape cannot be obtained. When b / a exceeds 4.0, the yarn-yarn abrasion deteriorated.

[0019]

[Table 2] Example 3 The same spinneret as in Example 1 was used, and the yarn was formed in the same manner as in Example 1 except that R was changed to obtain a 75D-36f drawn yarn.
If the diameter of the circular hole at the tip of the slit was less than 1.2, which is the slit width, the base was stained. Experiment No. 2 in which the slit hole diameter exceeded 2.0 times the slit width. In No. 15, ejection unevenness occurs,
The spots on the multifilament yarn also became worse. Table 3 shows the results.

[0020]

[Table 3] Example 4 The same spinneret as in Example 1 was used, and the yarn was formed in the same manner as in Example 1 except that θ was changed to obtain a drawn yarn of 75D-36f. If the angle θ is 87 ° or more, the yarn will have a special cross-sectional shape,
Yarn abrasion was also poor. Experiment No. in which θ was less than 80 °.
No. 19 had many thread breaks and could not be wound. Table 4 shows the results.

[0021]

[Table 4]

[0022]

As described above, by using the spinneret of the present invention, it is possible to stably obtain a polyester fiber having an H-shaped cross-sectional shape in which splitting (fiber cracking) hardly occurs. The polyester fiber obtained from the spinneret of the present invention, when applied to a material for clothing, especially a sports material, has remarkable effects of improving gloss and water absorption, which have not been achieved so far.

[Brief description of the drawings]

FIG. 1 is a detailed view of a slit according to the present invention.

FIG. 2 is a cross-sectional view of a synthetic fiber obtained by melt-spinning using the slit die of FIG. 1 according to the present invention.

FIG. 3 is a cross-sectional view of a conventional H-shaped synthetic fiber in which the H-shape is opened outward.

[Explanation of symbols]

 a: length of the slit to be joined b: average linear length opposing to each other c: slit width d: interval between the tip portions of the slit R: diameter of the circular hole θ: angle formed by the slit to be joined to the opposite slit

Claims (1)

[Claims] 1. An H-shaped spinneret comprising an opposing slit and a slit joining the opposing slits, wherein each end of the opposing slit has a circular shape and the circular hole diameter is R. (Mm), the average linear length of the opposing slits is b (mm), the length of the slit joining the opposing slits is a (mm), and the slit width is c (m).
m) An H-shaped slit spinneret satisfying the following formulas (1) to (3) at the same time when the bending angle of the opposed slit is θ. 2.6 ≦ b / a ≦ 4.0 (1) 1.2 ≦ R / c ≦ 2.0 (2) 80 ° ≦ θ ≦ 87 ° (3)