JPH1112844A - Spinneret device for spinning core-sheath conjugated hollow fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spinneret device for spinning a core-sheath conjugated hollow fiber without causing hollow breaking even when the melt viscosity of a core component polymer is higher than that of a sheath component polymer or a difference in polymer melt viscosity between a core and a sheath components is large. SOLUTION: This spinneret device for spinning a core-sheath conjugated hollow fiber comprises an independent polymer flow passage in any of introduction plates and is obtained by installing a discharge hole composed of three or more slits annularly arranged in a spinneret plate, forming the slits by combining circular arcs and locating the central point Q3 of the inner circular arc of the slits on the center line of the outer circular arc different from the central point Q2 of the outer circular arc in the spinneret device integrally composed in the upper and lower parts in the order of the upper introduction plate, the lower introduction plate and the spinneret plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spinneret for spinning a core-sheath hollow composite fiber, and more particularly, to a core using polymers having different melt viscosities such as a low melt viscosity core component polymer and a high melt viscosity sheath component polymer. The present invention relates to a core-sheath composite hollow fiber spinneret capable of obtaining a core-sheath composite hollow fiber that does not cause hollow cracks when formed into a sheath composite hollow fiber with good operability.

[0002]

2. Description of the Related Art Conventionally, various spinnerets for producing core-sheath composite hollow fibers have been proposed. For example, a spinneret for core-sheath porous hollow composite fibers has a slit-type orifice as disclosed in JP-A-7-292515. In the spinneret plate, a plurality of outer circumferential slits arranged in a ring shape through two or more discontinuous portions and a connecting slit and each connecting slit projecting from the center of the inner edge length of each outer circumferential slit to the center side of the orifice; There has been proposed a base plate for a core-sheath composite porous hollow fiber composed of communicating central slits. Since this die plate has a connecting slit communicating with the outer peripheral slit and the center hole, the discontinuous portion between the outer peripheral slit and the center hole is supported only at one discontinuous portion of the outer peripheral slit, and high viscosity is achieved. There is a problem that the die plate is easily distorted due to pressure and repeated fatigue caused by the polymer, and satisfactory operability of the core-sheath composite hollow fiber has not been achieved.

[0003] Also, JP-A-4-65507 discloses that
There has been proposed a spinneret device for obtaining a fiber having a hollow portion at the center of a composite fiber laminated in three layers. In this spinneret, each component is supplied from an individual inlet, and two side components are merged with the middle component at the inlet of the undiluted solution of the spinneret, and then a spinning hole composed of a plurality of arc slits is formed as a composite polymer. It is discharged from. In this case, the polymer discharged from the arc slit at the same time as being discharged from the arc slit in a state in which the three component polymers are compounded causes a phenomenon (kneeling phenomenon) in which the polymer is refracted toward the outer periphery of the arc slit. There is a problem that joining becomes difficult and hollow cracks occur.

Japanese Patent Application Laid-Open No. 57-56512 also discloses that when a core component having a low melt viscosity and a sheath component polymer having a high melt viscosity are introduced into a discharge hole as a core-sheath composite flow, the core component polymer is inserted into the arc slit. In the same manner as described above, a kneading phenomenon occurs in the encircling arc slit, resulting in a fiber having a hollow crack, and there is a problem that the operability is reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to produce a core-sheath composite hollow fiber which cannot be achieved by a conventional core-sheath composite hollow fiber spinneret. A core for producing a core-sheath composite hollow fiber which does not cause hollow cracking with good operability even when the melt viscosity is lower than the melt viscosity of the sheath component polymer or when the melt viscosity difference between the core component and the sheath component polymer is large. An object of the present invention is to provide a die device for a sheath composite hollow fiber.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cap device having an upper plate, a lower plate, and a base plate, which are integrally formed vertically in this order. And a discharge plate comprising three or more slits arranged in an annular shape in the base plate. The slit is a slit formed by combining circular arcs, and the center point Q3 of the inner circular arc of the slit is the outer circular arc. A core-sheath composite hollow fiber cap device (hereinafter referred to as a cap device) having a center point on the center line and different from the center point Q2 of the outer arc.
Can be achieved by

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. FIG. 1 is a longitudinal sectional view showing an example of the die device of the present invention. FIGS. 2A, 2B, 2C, and 2D are bottom views of the base plate showing an example of the shape of a discharge hole formed of a slit formed by combining circular arcs formed in the base plate. FIG. 3 is FIG.
FIG. 4 is a schematic view of a base plate for explaining the shape and arrangement of slits formed by combining arcs forming discharge holes of FIG.

1 to 3, reference numeral 1 denotes an upper introduction plate, 2 denotes a lower introduction plate, and 3 denotes a base plate. Reference numeral 4 denotes a discharge hole formed of a slit 5 formed by combining circular arcs formed in the base plate 3. The core component polymer A is supplied from the supply hole 6 of the upper introduction plate 1 and introduced into the base plate 3 through the supply hole 8 of the lower introduction plate 2, and the polymer B of the sheath component is supplied from the supply port 7 of the upper introduction plate 2. It is supplied and supplied from the supply hole 9 of the lower introduction plate 2 to form a core-sheath composite flow on the back surface of the base plate 3, and is discharged from the discharge hole 4 composed of the slit 5 formed by combining arcs. As described above, the spinneret of the present invention first supplies two types of polymers separately, then merges at the outlet of the lower inlet plate 2, that is, at the inlet of the spinneret plate 3 to form a core-sheath composite flow. The sheath composite flow is decomposed into a plurality of slits at the discharge hole 5 of the base plate 3 and discharged, and the polymer is bonded while taking in air immediately below the base plate to form hollow composite fibers. As described above, in order to form the core-sheath hollow conjugate fiber, it is necessary to provide a base device which is integrally formed vertically in the order of the upper introduction plate 1, the lower introduction plate 2, and the base plate 3.

The upper introduction plate 1 and the lower introduction plate 2 can use the introduction plates used in a general core-sheath composite spinneret, but the flow paths of the core component polymer and the sheath component polymer are independent. is necessary.

It is preferable that the lower introduction plate 2 is provided with a core component supply hole 8 and a sheath component supply hole 9 which is a satellite hole around the core component supply hole 8. The core component polymer supply hole 8 may be a modified hole or a round hole, but is preferably a round hole. Further, the number of the sheath component polymer supply holes 9 arranged around the core component polymer supply hole 8 is preferably three or more, more preferably six or more, for obtaining a stable cross section. In addition, it is preferable that the plurality of sheath component supply holes 9 arranged have the same discharge amount per hole in order to locate the core component in the center of the composite cross section, so that the hole diameter and the hole depth are the same. It is preferable that a certain round hole is formed in a point symmetric shape, that is, on the same track.

Next, the shape of the discharge hole of the die plate to be finally discharged will be described with reference to FIG. 3 showing an example of a discharge hole composed of four slits formed by combining arcs.

In FIG. 3, a circumscribed circle 10 has a center point Q1,
The outer arc of the slit formed by combining the radius r1 and the arc is the center point Q2, the radius r2, and the inner arc is the center point Q3, the radius r3.
With each.

The shape of the slit constituting the discharge hole is a slit formed by combining arcs, and the center point Q3 of the inner arc of the slit is located on the center line of the outer arc and different from the center point Q2 of the outer arc. It is necessary to be. This is because the slit width is continuously changed by setting the center point Q3 of the inner arc of the slit at a position different from the center point Q2 of the outer arc on the center line of the outer arc, so that the composite polymer discharged from the slit discharge hole is changed. This is for defining the flow bonding shape. As a result of the present inventors' experiments and studies on the effect of the slit shape on the core-sheath structure of the fiber cross section, it was possible to change the composite shape at the slit end by continuously changing the slit width. ,
It was found that the core component polymer could be prevented from being exposed on the fiber surface when the hollow composite fiber was formed.

Further, when the shape of the slit is defined by the radius of curvature of the slit, the outer radius of curvature r2 of the slit is 0.8 times the radius r1 of the circumcircle of the discharge hole from the center point Q1 of the circumcircle of the discharge hole as shown in FIG. The following is preferred. More preferably, it is 0.8 to 0.4 times. This is because the outer peripheral length of the slit can be made longer by making the outer arc curvature radius r2 of the slit smaller than the radius r1 of the circumcircle of the discharge hole. High hollowing can be achieved using the kneeling phenomenon of refraction.

The number of slits forming the discharge holes of the base plate is three.
It is necessary that the number is not less than 3, more preferably 3 to
There are six. If the number is less than 3, the fibers tend to be crushed by the merging force when they are merged immediately below the base plate, so that highly hollow fibers cannot be obtained. If the number of slits exceeds 6, the effect obtained by changing the radius of curvature is reduced.

The ratio r3 / r2 of the radius of curvature r3 of the inner arc to the radius of curvature r2 of the outer arc of the slit formed by combining the arcs is preferably less than 1. More preferably, it is 0.9 to 0.5. This is because, by making the width of the slit end portion wider than the width of the slit central portion, the discharge amount increases, the joining becomes easy, and the hollow cracks and the exposure of the core component from the joining surface can be prevented.

The polymer applied to the spinneret for spinning the core-sheath composite fiber of the present invention is not particularly limited. Examples thereof include polyolefins such as polyethylene and polypropylene, polyamides such as nylon 6 and nylon 66, polyethylene terephthalate, and the like. All thermoplastic polymers and copolymers, such as polybutylene terephthalate, are included. Further, a third component may be mixed with the polymer, or particles may be added for use. Further, the polymers used for the core component and the sheath component can be freely combined and used from the above-mentioned polymers.

FIG. 4 shows the cross-sectional shape of the fiber obtained by using the spinneret for spinning the core-sheath composite fiber. FIG. 4 is a cross-sectional view showing an example of a cross section of the core-sheath composite fiber after spinning and drawing, in which 11 is a core portion, 12 is a sheath portion,
13 is a hollow part.

With the above-described die apparatus of the present invention, the occurrence of hollow cracks when a core-sheath composite hollow fiber is formed using polymers having different melt viscosities, such as a core component polymer having a low melt viscosity and a sheath component polymer having a high melt viscosity. It is possible to obtain a core-sheath composite hollow fiber that does not have good operability.

[0020]

The present invention will be described in more detail with reference to the following examples. Each characteristic value in the examples was obtained by the following method.

A. Intrinsic viscosity [η] orthochlorophenol (hereinafter referred to as OCP) 10 ml
Was dissolved in 0.10 g of the sample, and the temperature was measured at 25 ° C. using an Ostwald viscometer.

Example 1 A polyethylene terephthalate having an intrinsic viscosity [η] of 0.64 was used as a sheath component, and an intrinsic viscosity [η] of 0.1 was used as a core component.
At 45, the 5-sodium sulfoisophthalic acid component is added to 2.5
Using a modified polyester obtained by mol% copolymerization, a slit formed by combining a circular arc with a discharge hole circumcircle radius r1 of 0.5 mm and a discharge hole at a spinning temperature of 290 ° C. by a general composite spinning machine at a spinning temperature of 290 ° C. From the circumscribed circle center point Q1 to 0.
An outer arc having a center point of curvature at a position 1 mm away and a radius of curvature r2 of 0.4 mm (0.8 times r1) and a center line of the outer arc at a position 0.15 mm away from the center point Q2 of the outer arc. A curvature radius r3 having a center point Q3 of curvature is 0.25 mm.
4 composed of an inner arc of (r3 / r2 = 0.625)
Slit discharge hole The core-in-sheath composite ratio is 20:80 using the die device of FIG. 1 in which the die plate composed of FIG. 2B is combined.
And the undrawn yarn was wound up at a spinning speed of 1350 m / min. The melt viscosity of each of the single polymers of the sheath component and the core component was 3000 poise and 1500 poise.
Further, the undrawn yarn was drawn at a draw ratio of 2.7 times using a usual hot roll / hot plate drawing machine to obtain a drawn yarn. The operability at this time was good without breakage.

This drawn yarn had a desired cross-sectional shape having a hollow portion at the core-sheath interface shown in FIG.

COMPARATIVE EXAMPLE 1 The diameter of the circumscribed circle of the discharge hole shown in FIG.
Spinning and stretching were carried out under the same conditions as in Example 1 except that a material having a final discharge hole comprising a slit having a slit width of 0.08 mm was used to obtain a drawn yarn. In this yarn, a kneading phenomenon occurs at a slit discharge hole in a spinning process, and there are many yarn breaks in a spinning and stretching process.
Observation of the cross-sectional shape as shown in FIG. 7 revealed hollow cracks and a low hollow ratio.

[0025]

According to the core-sheath composite hollow fiber spinneret of the present invention, the shape of the slit formed by combining the arcs constituting the discharge hole is determined by setting the center point Q3 of the inner arc of the slit on the center line of the outer arc. The slit width is continuously changed by setting it to a position different from the center point Q2, thereby defining the bonding shape of the composite polymer flow discharged from the slit discharge hole and preventing the core component polymer from being exposed on the fiber surface. I can do it. Further, the ratio r3 of the radius of curvature r3 of the inner arc to the radius of curvature r2 of the outer arc of the slit formed by combining the arcs.
By setting / r2 to less than 1, the width of the slit end becomes wider than the width of the center of the slit, thereby increasing the discharge amount, making it easy to join the polymers, and exposing the core component from hollow cracks and the joining surface. Can be prevented. Thus, even when the melt viscosity of the core component polymer is lower than the melt viscosity of the sheath component polymer or when the melt viscosity difference between the core component and the sheath component polymer is large, a core-sheath composite hollow fiber that does not cause hollow cracks is produced. It can be manufactured with good operability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a base device of the present invention.

FIG. 2 is a bottom view of the base plate showing an example of a shape of a discharge hole formed of a slit formed by combining circular arcs formed in the base plate;

FIG. 3 is a schematic diagram of a base plate for explaining the shape and arrangement of slits formed by combining arcs forming discharge holes in FIG. 2 (b).

FIG. 4 is a cross-sectional view showing an example of a cross section of a core-sheath composite hollow fiber obtained using the die device of the present invention.

FIG. 5 is a cross-sectional view showing an example of a discharge hole of a conventional die plate.

FIG. 6 is a cross-sectional view of a fiber obtained by the die plate of FIG. 5;

[Explanation of symbols]

 1: upper introduction plate 2: lower introduction plate 3: base plate 4: discharge hole 5: slit formed by combining circular arcs 6: upper introduction plate core component polymer supply hole 7: upper introduction plate sheath component polymer supply hole 8: lower introduction Plate core component polymer supply hole 9: Lower introduction plate / sheath component polymer supply hole 10: Discharge hole circumcircle 11: Core hole 12: Sheath 13: Hollow

Claims (3)

[Claims] 1. A base device integrally formed in the order of an upper introduction plate 1, a lower introduction plate 2, and a base plate 3, wherein each of the introduction plates has an independent polymer flow path, and the base plate has an annular shape. Discharge holes formed of three or more slits are arranged, and the slits are slits formed by combining arcs, and the center point Q3 of the inner arc of the slit is on the center line of the outer arc and the center of the outer arc. A core-sheath composite hollow fiber base device having a center point different from the point Q2. 2. The method according to claim 1, wherein the outer radius of curvature r2 of the slit formed by combining the arcs is not more than 0.8 times the radius r1 of the circumcircle of the discharge hole formed by the slit. Cap device for core-sheath composite hollow fiber 3. The core-sheath composite hollow fiber spinneret according to claim 1, wherein the ratio r3 / r2 of the radius of curvature of the inner arc to the outer arc of the slit formed by combining the arcs is less than 1.