JPH08325826A - Spinneret for specific hollow yarn - Google Patents

Abstract

PURPOSE: To provide a spinneret having >=20% hollow ratio, capable of readily and stably providing a highly hollow yarn of a specific shape comprising two hollow parts formed along a fiber axis. CONSTITUTION: This spinneret for hollow yarn having a high hollow ratio and two hollow parts is provided by equipping inner edges Ei parts at both ends of four or more slit flow channel holes Ha arranged on the periphery of an ellipse C1 with projected flow channel holes Hb, respectively, forming pairs of projected flow channels (A and B) of mutually adjoining, opposing and neighboring delivery holes and laying the two pairs A having larger open flow channel areas than the other pairs B at parts symmetric with respect to a major axis A1 among the pairs of the projected flow channel holes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has two hollow portions along a fiber axis and, when viewed in a cross section perpendicular to the fiber axis (hereinafter simply referred to as "fiber cross section"), A fiber having a high ratio of the occupied area of the hollow part in the whole fiber cross section (hereinafter referred to as “hollowness” or “hollowness”), that is, a hollow fiber having a hollowness of 20% or more is melt-spun. The present invention relates to a spinneret capable of producing a fiber which is lightweight, has a high heat retention property, and has a firm and firm feeling, and a sharp feeling.

[0002]

2. Description of the Related Art Conventionally, when melt-spinning a hollow fiber, as shown in FIGS. 3 (a) and 3 (b), a discharge hole (H ') having an arcuate slit-shaped flow path hole is the same. A spinneret for hollow fibers having a plurality of holes formed on the circumference has been generally used. However, the hollow fiber obtained by spinning from such a spinneret has a hollow portion formed along the fiber axis (hereinafter,
It has only one "hollow part"). Moreover, when it is attempted to obtain a hollow fiber having a high hollow ratio by using such a spinneret, as shown in FIGS. 4 (a), (b),
As shown in (c), the polymer discharged from the adjacent discharge holes may have a dent at the bonding portion, or the bonding may be defective.

Therefore, a spinneret for solving the above problems and obtaining a hollow fiber having a high hollowness and an improved roundness of the fiber cross section is disclosed in JP-A-58-16950.
It is proposed in Japanese Patent Publication No. 7. According to this spinneret, it is possible to obtain a spinneret having a relatively small hollowness of 20% or less. However, even if an attempt is made to produce a yarn having a high hollow ratio such as more than 30%, as shown in FIG.
As shown in (a), (b), and (C), distortion occurs in the shape of the fiber cross section, so it is difficult to obtain such a yarn. That is, even if an attempt was made to obtain a shape close to a perfect circle, there was a big problem that the fiber cross section was difficult to become a perfect circle.

A spinneret shown in FIGS. 7 (a) and 7 (b) is proposed to solve this problem and obtain a hollow fiber having a hollowness of more than 30% and excellent circularity. (Japanese Utility Model Publication No. 2-43879). Note that FIG.
(A), (b), (C) are hollow fibers obtained from these spinnerets.

However, all of these spinnerets are spinnerets for producing hollow fibers having one hollow portion.

On the other hand, Japanese Patent Application Laid-Open No. 6-2210 proposes a spinneret for producing a hollow fiber having two or more hollow portions as shown in FIG.
0 shows the fiber cross section of the hollow fiber obtained from this spinneret. However, in this spinneret, the shape of the hollow portion of the obtained hollow fiber is extremely irregular, and it is extremely difficult to obtain a hollow fiber having a hollow ratio of 20% or more. For this reason, it was not possible to stably obtain a hollow fiber having a high hollow ratio of 20% or more having two or more hollow portions, which has both lightness and heat retention. Moreover,
Since the area occupied by the projecting flow path holes is small, there is a problem in that the joint portion for forming the hollow portion is weakened and hollow cracks occur.

[0007]

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the prior art and has two hollow portions.
Moreover, it is intended to provide a spinneret for stably producing a hollow fiber having a hollow ratio of 20% or more.
If such a spinneret is to be provided,
A hollow fiber having two hollow portions and having a high hollow ratio can be stably and reliably produced, and a hollow fiber excellent in lightness and heat retention can be obtained.

[0008]

According to the present invention, there is provided a spinneret having the following constitution in which the above-mentioned problems are solved very skillfully.

That is, according to the present invention, a special hollow fiber formed along a fiber axis and having two substantially independent hollow portions, which simultaneously satisfies the following conditions A to E, is used. It is a spinneret for hollow fibers. For a special hollow fiber having a plurality of discharge holes that simultaneously satisfy the following requirements A to E, for spinning a special hollow fiber having two substantially independent hollow portions formed along a fiber axis. Spinneret. A. 1. The major axis length / minor axis length (A1 / A2) is 1.0 or more, 2.
4 or more and 12 or less slit-shaped channel holes (Ha) are arranged along the circumference of an ellipse (C1) of 0 or less, and B. At both ends of the inner edge (Ei) portion of the slit-shaped flow passage hole (Ha), there are provided projection flow passage holes (Hb) that protrude inward in a direction substantially perpendicular to the ellipse (C1). Between the adjacent slit-shaped flow channel holes (Ha), the projecting flow channel holes that closely face each other are paired with each other. A circumscribed ellipse (C) circumscribing the outer edge (Eo) of each slit-shaped channel hole (Ha) on the polymer discharge surface of the die.
The area area surrounded by 2) is defined as S1, and the opening flow path area of the discharge hole formed by being surrounded by the wet edge of the polymer is defined as S2, which is established between these S1 and S2.
When the relational expression of the channel occupancy (R) = (S2 / S1) × 100 is assumed, the channel occupancy is 3 ≦ R ≦ 10, and C.I. The interval (t) between the slit-shaped flow path holes (Ha) adjacent to each other is 0.05 mm or more and 0.1 mm or less, and D. In the projecting flow path holes forming a pair with each other, within the range of 20% of the major axis length (A1) from the major axis center (O) of the ellipse (C1) toward the two major axis ends, the other Two pairs (A) having a larger opening channel area than the pair of protruding channel holes (B) are provided so as to face each other in a line symmetry with respect to the major axis of the ellipse (C1), and E. The ratio of the total opening flow passage area on the die discharge surface composed only of the group of protruding flow passage hole pairs (group A) with respect to S2 is
The percentage is 6.0% or more and 10.0% or less,
On the other hand, 2.0% for the group of protruding channel hole pairs (Group B)
It should be 5.0% or less.

In the structure of the present invention, the protruding flow path hole (Hb) has a slit shape, the slit length (L) is 0.10 mm or more and 0.12 mm or less, and the slit width ( W) is 0.004 mm or more, 0.06
two pairs of projecting flow path holes having a large opening flow path area of mm or less, and a slit length (L) having an opening flow path area smaller than 0.1 mm is 0.10 mm or more and 0.12 mm or less, Slit width (W) is 0.004 mm or more,
It is preferable to use a spinneret composed of another pair of projecting flow path holes having a diameter of 0.06 mm or less.

The major axis length of the ellipse (C1) is 1.
A thickness of 0 mm or more and 3.0 mm or less is preferable in order to obtain a fine denier hollow fiber that is lightweight and has excellent heat retention.

[0012]

EXAMPLE Next, an example of a spinneret having two hollow portions and having a high hollow ratio and having the above-mentioned structure will be described in detail below together with its operation.

When melt-spinning a hollow fiber, the polymer discharged from the spinneret undergoes a phenomenon of swelling immediately after discharge (so-called ballast effect), and thereafter, thinning starts. This ballast effect plays an extremely large role in the hollowness of the obtained hollow fiber. That is, generally, when the melting temperature of the polymer becomes low, the dispersion effect of the polymer discharged from the discharge hole becomes large, and the hollowness of the obtained hollow fiber becomes high. However, on the other hand, the arc-shaped shape of the polymer discharged from the discharge holes is difficult to be maintained as it is, and the fiber cross-sectional shape of the obtained yarn is variously modified according to the number of discharge holes. To do. That is, in the case of a discharge hole having two arcuate slit-shaped flow path holes, it tends to be elliptical, in the case of three discharge holes it is triangular, and in the case of four discharge holes it is likely to be square. Further, in such a case, the polymers discharged from the discharge holes adjacent to each other do not bond well to each other, and hollow cracks often occur.

Therefore, in the present invention, as a means for suppressing the above-mentioned hollow cracks, projecting flow passage holes (Hb) are provided at both ends of the inner edge (Ei) of the discharge hole having a circular or elliptical slit-like flow passage hole. I am setting up. The protruding flow path hole (Hb) plays a role of increasing the flow path cross-sectional area of the discharge hole. For this reason, the linear flow velocity of the polymer is slowed by the projecting flow path hole, whereby the stress of the polymer swelling outward immediately after the discharge is relieved. And
The effect of maintaining the arc shape at the time of discharging the polymer is imparted.

However, one of the major features of the present invention is to stably and surely form hollow portions having two opening hollow ratios. For this purpose, the number and shape of the discharge holes having the projecting flow passage holes are formed. , It is important that the arrangement has the above-mentioned configuration.

As described above, in the present invention,
The protruding channel hole (Hb) plays a very important role. Hereinafter, examples of the spinneret having protruding channel holes of the present invention will be described in more detail.

In general, the hollow cross-sectional shape of the hollow fiber largely depends on the spinning conditions such as the melt viscosity of the polymer, the discharge linear velocity and the cooling condition, but as described above, the slit-shaped flow passage hole (Ha) is used. ) And the number of protruding channel holes (Hb), shape,
Placement also has a big effect.

Therefore, the discharge holes provided in the spinneret of the present invention will be described in detail below with reference to the drawings together with specific parameters. FIG. 1 (a) shows that a spinneret is provided with
FIG. 1 shows a plan view of a discharge hole which is a basic unit for spinning one single fiber, and FIGS. 1 (b) and 1 (c) show a spinneret formed according to another embodiment of the present invention. It is a top view of the discharge hole. In addition, as a reminder, it is needless to say that in order to spin the multi-filament, a spinneret in which the discharge holes made of the above-mentioned basic units are provided in correspondence with the number of filaments is used. Note that FIG. 1 (b)
In and (c), when the major axis length and the minor axis length of the ellipse (C1) indicated by the one-dot chain line match (major axis length / minor axis length = 1), that is, the ellipse (C1) is a circle (C1). ´)
It goes without saying that the present invention also includes such cases. 2 shows a fiber cross section of a hollow fiber obtained by melt spinning with the spinneret of FIG. 1, and shows an example in which two hollow portions are formed with a high hollow ratio. It is a schematic diagram of a cross section.

In FIG. 1 (a), the spinneret of the present invention has four discharge holes formed along the circumference of the ellipse (C1) at a slight interval (t). It has slit-shaped channel holes (Ha). Here, as the shape of the ellipse (C1) on which the slit-shaped flow path hole (Ha) is arranged, when the major axis length is A1 and the minor axis length is A2, the major axis length (A1 ) To the minor axis length (A2) (A1 / A
It is important that 2) is 1.0 or more and 2.0 or less in order to produce a high hollow fiber. If this ratio (A1 / A
When 2) exceeds 2.0, the hollow part has a crushed shape, which makes it difficult to obtain a high hollow fiber. 1B and 1C, the major axis length (A1) = the minor axis length (A
2) = Pitch circle diameter (PCD) is shown.

Next, in order to prevent the formation of yarns having poor polymer bonding as shown in FIG. 4, an ellipse (C1) is formed at the inner edges (Ei) of both ends of each slit-shaped channel hole (Ha). ) Of the flow passage hole (H
It is important to provide b), and between adjacent slit-shaped flow channel holes (Ha), the projecting flow channel holes that closely face each other are paired (A or B). The discharge hole of this embodiment is provided with protruding flow passage holes (Hb) at both ends thereof.
It consists of individual slit-shaped channel holes (Ha),
The number of slit-like flow passage holes (Ha) is preferably 4 or more and 10 or less in order to obtain a good hollow fiber.

In the present invention, since it is essential to form the two hollow portions with a high hollow ratio, it has been repeatedly mentioned that the shape and arrangement of the protruding flow passage holes (Hb) are important. By the way. Therefore, the protrusion channel hole (H
The shape and arrangement of b) will be specifically described according to the embodiment.

First, regarding the arrangement of the pair (A and B) of the protruding flow channel holes (Hb) illustrated in FIG. 1A, the opening of the pair (B) of the other protruding flow channel holes (Hb) is used. Two pairs (A) of protruding channel holes (Hb) having a large channel area are provided. Then, within the range of 20% of the major axis length from the major axis center (O) of the ellipse (C1) toward both ends of the major axis, the two pairs (A) are related to the major axis of the ellipse (C1). , It is important that they are provided so as to face each other substantially in line symmetry. If it does not fall within this range, it becomes difficult to obtain a high hollow fiber, and it becomes difficult to achieve the object of the present invention.

By doing so, in particular, the discharge linear velocity of the polymer flowing through the pair of projecting flow passage holes (A) having a larger opening flow passage area than that of the other pair of projecting flow passage holes (B) is different. Slower than the part. Therefore, as described above, the stress bulging outward at the portion of the pair of protruding flow channels (A) is remarkably relaxed,
It is considered that the polymer in this portion comes close to each other to cause bonding, thereby forming two hollow portions.

Here, the above-mentioned slit-shaped channel holes (Ha)
Are arranged on the circumference of the ellipse (C1), and the major axis length at this time is preferably 1.0 mm or more and 3.0 mm or less. If the major axis length is too small, a high hollow ratio is obtained. Not only is the yarn undesired, but it also becomes difficult to form a hollow yarn having two hollow portions. Conversely, if it is too large, it is difficult to obtain a fine denier hollow fiber.

Further, the area of the entire region surrounded by the circumscribing ellipse (C1) circumscribing the outer edge (Eo) of the slit-shaped flow passage hole (Ha) is defined as S1, and is surrounded by the wetting edge of the polymer of the discharge hole. If the formed total opening channel area is defined as S2, these S1 and S2 are 3 ≦ R = (S2 / S1)
It is necessary to satisfy the relational expression of × 100 ≦ 10. In this relational expression, R is the "flow passage occupancy rate"
I will call it. If the flow channel occupancy rate is less than 3, the bonded portion of the polymer as shown in FIG. 4 becomes a defective hollow fiber, and if it is greater than 10, it becomes difficult to obtain a hollow fiber having a high hollow rate. However, the flow passage occupancy rate is
It is largely influenced by the gap (t) separating the arcuate slit-shaped flow passage holes (Ha) adjacent to each other. In addition to the relationship between the interval (t) and the flow passage occupancy (R), generally, when t is small, R is selected to be a small value, and when t is large, R is conversely selected. It is preferable to select a large value.

At this time, in the above-mentioned protruding channel hole pair (A and B), the channel occupancy ratio of two pairs (A) having a larger opening channel area than the other protruding channel hole pair (B). It is preferable that the flow passage occupancy of the other protrusion pairs (B) is 2.0 or more and 4.0 or less and 6.0 or more and 10.0 or less.

Further, regarding the shape of such a pair of projecting flow passage holes (A and B), it is essential to have the above flow passage occupation ratio (R). However, it is particularly preferable to form the slit shape mainly in view of processing (manufacturing) of the flow path, and regarding the shape, the slit length (L) is smaller than that of the protruding flow path hole pair (A). 0.10 mm or more, 0.
12 mm or less and the slit width (W) is 0.004
It is preferable that it is not less than mm and not more than 0.06 mm. Then, for the protruding flow path hole pair (B), the slit length (L) is 0.10 mm or more and 0.12 mm or less, and the slit width (W) is 0.004 mm or more and 0.06.
It is particularly preferable that it is not more than mm.

By the way, as a matter of course, the above-mentioned interval (t) has a preferable value, which is 0.05 mm or more,
It is important to set it to 0.1 mm or less. If t is too small, the extruded polymer will be bonded quickly,
This is not preferable in terms of strength design of the spinneret because it tends to be a flat hollow fiber, and further, the spinneret is easily deformed by the discharge pressure of the polymer. Further, if t becomes too large, the bonding is delayed, and thus the bonding of the polymers is not sufficiently performed, which causes hollow cracks. Further, the narrower the slit width (w) of the arc-shaped slit-shaped flow path hole (Ha) of the discharge hole, the higher the hollow rate of the yarn that can be obtained, which is when the polymer is discharged from the spinneret. It is closely related to the discharge pressure, and the discharge pressure increases as it becomes thinner, so it may be appropriately selected depending on the properties of the polymer and the spinning conditions.

Finally, an experimental example using the spinneret having the above-described discharge holes will be described below.

Along the circumference of the ellipse having a major axis length (A1) of 1.7 mm and a major axis length (A1) / minor axis length (A2) = 1.2. Slit-shaped channel hole (Ha)
Were placed with a spacing (t) of 0.007 mm. At this time,
Ellipse (C1) with 7% occupancy ratio (R) of the discharge holes
At the center of the long axis of the pair of protruding flow path holes (Hb) whose opening flow channel area is larger than that of the other pair of protruding flow path holes (Hb) (B) at a position line-symmetrical to the long axis. Two pairs of A) were formed. At this time, the opening channel area (S
The ratio of the opening channel area of the pair (A) of the protruding channel holes (Hb) to 2) is set to 9%, and the opening channel area of the pair (B) of the protruding channel holes (Hb) is Occupy 4%
And The width (W) of the slit channel hole at this time
Was 0.10 mm. When a polyester fiber is spun according to a standard method using this spinneret, hollow cracks are not generated, and it is possible to stably produce a hollow fiber having two hollow portions along the fiber axis direction. did it. When the cross section of the hollow fiber thus obtained was observed, the hollow rate was 24%.

The ratio (A1 / A2) of the major axis length (A1) to the minor axis length (A2) is 1.0, and A1 = A2 = 1.4 m
4 of equal length on the perimeter of an ellipse of m (which is effectively a circle)
The slit-shaped channel holes (Ha) were arranged at intervals (t) of 0.007 mm. The other conditions were the same as in the above experimental example, and a hollow fiber having two hollow portions was manufactured. When the cross section of the fiber obtained at this time was observed, it was found to have a high hollow ratio of 23% and no hollow crack was generated.

[0032]

As described above, according to the present invention, a high hollow fiber having two hollow portions can be stably and reliably spun without the occurrence of hollow cracks, which makes it lightweight. It is possible to obtain a material that has high heat retention and a firm and elastic feel. Further, since it is not necessary to change or adjust the viscosity of the polymer to be spun into unstable spinning conditions, it is possible to carry out stable spinning without causing yarn breakage. For this reason, there is an extremely remarkable effect that it is possible to obtain a high-quality yarn with excellent yarn-forming performance.

[Brief description of drawings]

FIG. 1A is a plan view of a discharge hole formed in a spinneret showing an embodiment of the present invention. (B) And (c) It is a top view of the discharge hole which shows other Examples.

FIG. 2 is a view exemplifying a fiber cross section (cross section in a direction transverse to a fiber axis) of a hollow fiber obtained in a discharge hole of FIG.

FIG. 3A and FIG. 3B are plan views showing conventional discharge holes.

4 (a) is a fiber cross-sectional view of the hollow fiber obtained in the discharge hole shown in FIG. 3 (a). (B) And (c) It is a fiber cross-sectional view of the hollow fiber obtained in the discharge hole of FIG. 3 (b).

FIG. 5 is a plan view showing another conventional discharge hole.

6 is a fiber cross-sectional view of a hollow fiber spun in the discharge hole of FIG.

FIG. 7 is a plan view showing another conventional discharge hole.

8 is a fiber cross-sectional view of a hollow fiber spun in the discharge hole of FIG.

FIG. 9 is a plan view showing another conventional discharge hole.

10 is a fiber cross-sectional view of a hollow fiber spun in the discharge hole of FIG.

[Explanation of symbols]

 1 Spinneret body A1 Long axis length A2 Short axis length A Protruding channel hole pair (small channel area) B Protruding channel hole pair (large channel area) C1 Ellipse C1 ′ Pitch circle C2 Circumscribing ellipse C2 ′ Circumscribing circle Ei Inner edge Eo Outer edge Ha Slit-shaped channel hole Hb Projected channel hole L Slit length of projecting channel hole O Center of major axis PCD Pitch circle diameter t Distance between adjacent discharge holes W Slit-shaped channel hole width

Claims (3)

[Claims] 1. A plurality of discharge holes, which simultaneously satisfy the following requirements A to E, for spinning a special hollow fiber having two substantially independent hollow portions formed along a fiber axis. A special spinneret for hollow fibers. A. 1. The major axis length / minor axis length (A1 / A2) is 1.0 or more, 2.
4 or more and 12 or less slit-shaped channel holes (Ha) are arranged along the circumference of an ellipse (C1) of 0 or less, and B. Protruding channel holes (Hb) protruding in a substantially inward normal direction of the ellipse (C1) are provided at both ends of the inner edge (Ei) portion of the slit-shaped channel hole (Ha).
Between the adjacent slit-shaped flow channel holes (Ha), the projecting flow channel holes that closely face each other are paired with each other. A circumscribed ellipse (C) circumscribing the outer edge (Eo) of each slit-shaped channel hole (Ha) on the polymer discharge surface of the die.
The region area surrounded by 2) is defined as S1, and the opening channel area of the discharge hole formed by being surrounded by the wet edge of the polymer is defined as S2, which is established between these S1 and S2.
When the relational expression of flow passage occupancy (R) = (S2 / S1) × 100 is assumed, the flow passage occupancy is 3 ≦ R ≦ 10, and C.I. The interval (t) between the slit-shaped flow path holes (Ha) adjacent to each other is 0.05 mm or more and 0.1 mm or less, and D. In the projecting flow path holes forming a pair, within the range of 20% of the major axis length (A1) from the major axis center (O) of the ellipse (C1) to the other major axis ends, the other Two pairs (A) having a larger opening channel area than the pair of protruding channel holes (B) are provided so as to face each other in a line symmetry with respect to the major axis of the ellipse (C1), and E. The ratio of the total opening flow passage area on the die discharge surface composed only of the group of protruding flow passage hole pairs (group A) with respect to S2 is
The percentage is 6.0% or more and 10.0% or less,
On the other hand, 2.0% for the group of protruding channel hole pairs (Group B)
It should be 5.0% or less. 2. The protruding flow passage holes (A and B) are slit-shaped, the slit length (L) is 0.10 mm or more and 0.12 mm or less, and the slit width (W) is 0. Two pairs of protruding flow path holes (A) having a size of 0.004 mm or more and 0.06 mm or less, and a slit length (L) of 0.10 mm or more and 0.12 mm or less and a slit width (W) of 0.004 mm that's all,
The spinneret for a special hollow fiber according to claim 1, which comprises another pair of projecting flow passage holes (B) having a diameter of 0.06 mm or less. 3. The major axis length of the ellipse (C1) is 1.0 m.
The spinneret for a special hollow fiber according to claim 1 or 2, which has a length of m or more and 3.0 mm or less.