JPH07292515A - Spinneret for sheath-core porous conjugate fiber - Google Patents

Abstract

PURPOSE:To provide the spinneret enabling to produce a smoothly joined sheath- core hollow conjugate fiber having an excellent quality in good operability without causing a kneeling phenomenon on a conjugated polymer extruded from the slit of an orifice, even when polymers having a large difference between the melt viscosities are used for the core component and the sheath component, respectively. CONSTITUTION:In the spinneret used for the sheath-core porous conjugate fibers and having a slit type orifice, the orifice comprises plural outer peripheral slits 1 circularly disposed through two or more discontinued parts 2, connected slits 3 each projected from the center of the inner edge length of each outer peripheral slit 1, and a central slit 4 communicating with the respective connected slits 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a spinneret for obtaining a core-sheath porous hollow composite fiber having two or more hollow parts by using polymers having different melt viscosities, in which hollow cracking (peeling) occurs. The present invention relates to a spinneret capable of obtaining core-sheath porous hollow composite fibers with good operability.

[0002]

2. Description of the Related Art Various spinnerets for producing core-sheath hollow composite fibers composed of multiple components have been proposed.
Japanese Patent No. 370213 discloses a spinneret device in which polymers of a core component and a sheath component are individually supplied, and after these are merged, a composite polymer is discharged from a discharge hole composed of a plurality of arc slits of a die plate. ing. This mouthpiece device is a mouthpiece device that is integrally configured in the order of an upper introduction plate, a lower introduction plate, and a mouthpiece plate.The upper introduction plate has a supply hole for individually supplying a polymer of a core component and a sheath component. The plate has a deformed hole for introducing the core component polymer from the supply hole and a plurality of round holes for introducing the sheath component polymer from the supply hole around the deformed hole. A discharge hole composed of an arc slit is provided.

According to this mouthpiece device, after the polymers of the core component and the sheath component are merged at the inlet of the mouthpiece plate, the composite polymer is discharged from an arc slit having a plurality of discontinuous portions of the mouthpiece plate. It is discharged from the hole. The arc slit has a substantially uniform width, and since the composite polymer is discharged from the arc slit in a form in which the core component and the sheath component are bonded together at the slit inner peripheral portion and the outer peripheral portion, the melt viscosity of the core component polymer is sheath. If the melt viscosity is lower than that of the component polymer, it is discharged from the arc slit and, at the same time, a phenomenon of refracting in the circumferential direction of the arc slit (kneeling phenomenon) occurs. This makes it difficult for the polymers discharged from other adjacent arc slits to bond to each other, resulting in a fiber having hollow cracks.

Further, Japanese Patent Application Laid-Open No. 53-74134 proposes a spinneret for porous hollow fibers in which each slit communicates with each other near the center of the orifice, but the slit on the outer peripheral side and the slit near the center are Since the width is substantially uniform, when the discharged polymer is a single component, a porous hollow fiber without hollow cracks can be obtained, but the discharged polymer consists of a composite component, and the melt viscosity of the core component polymer is When the melt viscosity is lower than that of the sheath component polymer, the composite polymer is discharged from the slit in a form in which the core component and the sheath component are laminated,
There has been a problem that a kneeling phenomenon occurs, resulting in fibers having hollow cracks, or the core portion is not the fibers formed at the center of the fibers.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and when the melt viscosity of the core component polymer is lower than that of the sheath component polymer, or the difference in melt viscosity between the core component and the sheath component polymer is large. Even in the case, hollow crack does not occur when the composite polymer is discharged from the orifice composed of the slit, and the core-sheath porous hollow composite fiber having the core formed in the center of the fiber can be spun with good operability. The technical problem is to provide a spinneret that can be used.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that in a spinneret for a porous hollow composite fiber having a slit type orifice, the orifice is discontinuous. A plurality of outer peripheral slits arranged in an annular shape through, if it is composed of a connecting slit protruding from the center of the inner edge length of the outer peripheral slit to the center side of the orifice and a central slit communicating with each connecting slit near the center of the orifice, The polymer of the core component is collected and discharged in the central slit, and only the polymer of the sheath component is discharged from the end of the outer peripheral slit having the discontinuity, so that the polymers of the sheath components are easily joined to each other, resulting in hollow cracking. The present inventors have found that a core-sheath porous hollow composite fiber having a core portion formed in the center of the fiber can be spun with good operability and reached the present invention.

That is, according to the present invention, in a spinneret having a slit-type orifice, the orifice is formed from a plurality of outer peripheral slits arranged annularly through two or more discontinuous portions, and the center of the inner edge length of each outer peripheral slit. A gist of a spinneret for core-sheath porous hollow composite fibers, comprising a connecting slit protruding toward the center of an orifice and a central slit communicating with each connecting slit.

The present invention will be described in detail below with reference to the drawings. 1 (a), (b), (c), and (d) are plan views showing an embodiment of a slit constituting an orifice of a spinneret of the present invention, and FIGS. 2 (a), (b), (C),
(D) is a schematic cross-sectional view of a core-sheath hollow composite fiber obtained by using the spinneret having the orifices of FIGS. 1 (a), (b), (c), and (d), and FIG. 3 shows the present invention. FIG. 3 is a cross-sectional view showing an embodiment of a spinning device equipped with the spinneret (capillary is not cut).

The slit type orifice A of the spinneret for core-sheath hollow composite fibers of the present invention is shown in FIGS. 1 (a), 1 (b),
As shown in (c) and (d), two or more discontinuous portions 2
A plurality of outer peripheral slits 1 (1a, 1b ... 1n) arranged in an annular shape through (2a, 2b ... 2n),
Connection slits 3 (3a, 3b ... 3) protruding from the center of the inner edge length of each outer peripheral slit 1 toward the center P of the orifice
n) and a central slit 4 communicating with each connecting slit 3 near the center P of the orifice.

As described above, the central slit 4 which has the connecting slit projecting from the center of the inner edge length of each outer peripheral slit 1 toward the center of the orifice, and which communicates with each connecting slit 3 at a position including the center P of the orifice. By providing, when the composite polymer in which the polymer of the core component and the polymer of the sheath component merge in a core-sheath shape is discharged, most of the polymer of the core component is
The polymer of the core component does not exist at the end of the outer peripheral slit 1 discharged from the central slit 4 and close to the discontinuous portion 2, and only the polymer of the sheath component is discharged. As a result, the sheath component polymer discharged from the end portions of the adjacent outer peripheral slits 1 can be easily joined by the ballast effect before the kneeling phenomenon occurs, and the core portion without hollow cracks as shown in FIG. A fiber formed at the center of the fiber is obtained.

On the other hand, the connecting slits 3 are connected to the respective outer peripheral slits 1.
When the central portion slit 4 communicating with each connecting slit 3 is not provided at a position deviated from the center of the inner edge length of the or the position including the center P of the orifice, the polymer of the core component is
Connection slit 3 in the form of being pasted with the polymer of the sheath component
The polymer of both the core and sheath components flows into the discontinuous portion 2 by being discharged from the outer peripheral slit 1 or the slit end portion close to the discontinuous portion 2. Therefore, the core is a fiber that is not formed in the center of the fiber, or a kneeling phenomenon occurs immediately after discharge, it becomes impossible to join the polymers of the sheath component discharged from the end of the adjacent outer circumferential slit, hollow A bimetallic C-shaped yarn or flat yarn in which cracks occur is generated, and the target core-sheath hollow composite fiber cannot be obtained.

The opening area of the central slit 4 is preferably 0.1 times or more the total opening area of the outer peripheral slit 1 and the connecting slit 3 excluding the central slit 4, and more preferably 0.15 times or more. preferable. If the opening area of the central slit 4 is too small, the pressure loss of the central slit 4 cannot be sufficiently reduced. Therefore, when the polymer of the core component is a low melt viscosity polymer having a high polymer flow rate,
A large amount cannot be discharged from the central slit 4, and it easily flows into the discontinuous portion 2, and a kneeling phenomenon occurs immediately after discharging, and the fibers are likely to have hollow cracks.

In the present invention, the plurality of outer peripheral slits are arranged in an annular shape, but the annular shape is not limited to a circular shape, and if each outer peripheral slit is connected through a discontinuous portion, It may be triangular, quadrangular, or the like. Further, the number of outer peripheral slits is not particularly limited as long as it has two or more discontinuous portions, and the shape of the central slit is not particularly limited, such as a circle, a rectangle, or a polygon. Absent.

Next, a method for spinning a core-sheath porous hollow composite fiber using the spinneret of the present invention will be described with reference to FIG. First, the sheath component polymer is introduced through the guide hole 13 of the upper mouth plate 15. The introduced sheath component is introduced into the discharge guide hole 11 from the communicating gap 12, and then is quantitatively supplied to the introduction hole 7 from the wall surface side by the notch 10 of the capillary 6. On the other hand, the core component polymer is introduced from the upper end of the capillary 6 communicating with the lower metal plate 14, and the introduced core component passes through the capillary guide hole 9 and the capillary discharge provided at the tip of the capillary guide hole 9. It is supplied quantitatively to the introduction hole 7 through the hole 8. At this time, the core component polymer becomes a composite polymer in which both the core and the sheath components are merged in a form wrapped in the sheath component polymer, and the composite polymer is extruded from the slit type orifice A through the introduction hole 7.
The polymer of the core component is discharged from the central slit 4, the polymer of the sheath component is discharged from the end of the outer peripheral slit 1, and the polymer of the sheath component discharged from the end of the adjacent outer peripheral slit 1 is Bonded to obtain a core-sheath porous hollow composite fiber having two or more hollow parts as shown in FIG. 2 and a core part formed at the center of the fiber.

When spinning is carried out using the spinneret for hollow-sheath porous composite fibers of the present invention, most of the core component polymer is not discharged from the slit in the state where the core and sheath component polymers are laminated, Since only the polymer of the sheath component is discharged from the end slits of the peripheral slits and the polymer of the sheath component is hardly affected by the difference in the melt viscosity of the polymer of the core and the polymer of the sheath component, A good fiber without hollow cracks can be obtained by spinning a combination of polymers having a large particle size. Furthermore, either the core or the sheath component polymer may be the high melt viscosity polymer.

[0016]

By using the spinneret for core-sheath porous hollow composite fibers of the present invention, even if a polymer having a large difference in melt viscosity between the core component and the sheath component is used, there is no hollow crack and the core portion is in the center of the fiber. It becomes possible to produce the formed core-sheath porous hollow composite fiber of excellent quality with good operability.

[Brief description of drawings]

FIG. 1 (a), (b), (c), (d) is a plan view showing an embodiment of a slit constituting an orifice of a spinneret for a hollow core / sheath composite fiber of the present invention.

2 (a), (b), (c) and (d) are for core-sheath porous hollow composite fibers having the orifices of (a), (b), (c) and (d) of FIG. It is a cross-sectional schematic diagram of the core-sheath porous hollow composite fiber obtained using a spinneret.

FIG. 3 is a cross-sectional view (without cutting the capillaries) showing one embodiment of a spinning device equipped with a spinneret for porous hollow-core composite fibers of the present invention.

[Explanation of symbols]

 1 Outer peripheral slit 2 Discontinuous part 3 Connection slit 4 Center part slit A Orifice P Orifice center

Claims (2)

[Claims] 1. In a spinneret having a slit type orifice, the orifice is a plurality of outer peripheral slits annularly arranged through two or more discontinuities, and the center of the inner edge of each outer peripheral slit is closer to the center of the orifice. A spinneret for a hollow core-sheath composite fiber having a core-sheath, characterized by comprising a connecting slit projecting to the side and a central slit communicating with each connecting slit. 2. The hollow core-sheath hollow according to claim 1, wherein the opening area of the central slit is 0.1 times or more of the total opening area of the outer peripheral slit and the connecting slit excluding the central slit. Spinneret for composite fibers.