JPH07310224A - Spinneret for core-sheath hollow conjugate fiber and production of core-sheath hollow conjugate fiber - Google Patents

Abstract

PURPOSE:To provide a spinneret enabling smooth conjugation of a core component and a sheath component without causing the kneeling phenomenon of the conjugate polymer extruded from the slit of the orifice even by using polymers having large melt viscosity difference as the core component and the sheath component and capable of producing a core-sheath hollow conjugate fiber having excellent quality in high operability without causing the breakage of the hollow part. CONSTITUTION:This spinneret 1, 2 has a notch to form a channel for supplying a component A to the outer circumference of a capillary 3 for the conjugate spinning of two different kinds of spinning components A and B in the form of a core-sheath conjugate fiber. The spinneret has the following constructions (1) and (2). (1) The capillary ejection port 6 of the capillary 3 is opened between the center point of the capillary and the inner wall of a capillary guiding hole 7 and excluding the capillary center point. (2) The capillary ejection port 6 is opened at a position outside of an angle K formed by both edges of the inner sides of a discontinuous part 12 of the slit constituting the orifice 4 opened on the lower spinneret plate 1 and the center point of each space surrounded by the slit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a spinneret and a spinneret capable of obtaining core-sheath hollow composite fibers which do not cause hollow cracking (peeling) with good operability by using polymers having different melt viscosities. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, various spinnerets for producing a core-sheath type hollow composite fiber composed of multiple components have been proposed. For example, Japanese Patent Laid-Open No. 4-370213 discloses a polymer for a core component and a polymer for a sheath component individually. A mouthpiece device is disclosed in which, after supplying and merging these, the composite polymer is discharged from a discharge hole formed of a plurality of arc slits of a mouthpiece plate. 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 united and merged at the inlet of the mouthpiece plate, the composite polymer is discharged from a discharge hole constituted by a plurality of arc slits of the mouthpiece plate. Therefore, the composite polymer discharged from the arc slit is discharged in a form in which the core component and the sheath component are bonded to each other on the inner peripheral portion and the outer peripheral portion of the slit. Therefore, when the melt viscosity of the core component polymer is lower than the melt viscosity of the sheath component polymer, a phenomenon (kneeling phenomenon) of refracting toward the outer circumferential direction of the arc slit at the same time as being discharged from the arc slit, causes another arc to approach. There is a problem that it becomes difficult to bond with the polymer discharged from the slit, and hollow cracks occur.

Further, in Japanese Patent Laid-Open No. 4-65507, a spinneret device for obtaining a fiber in which a hollow part is provided at the center of a composite fiber in which a middle part component and two side part components are laminated in three layers Is disclosed. In this spinneret device, each main distribution plate above the spinneret plate is provided with individual introduction holes, and each component is supplied from each individual introduction hole, and two side components are introduced at the stock solution inlet of the spinneret plate. After being mixed with the middle component, the composite polymer is discharged from a spinning hole composed of a plurality of arc slits. Also in this spinneret device, the melt viscosity of the polymer of the middle component is the melt viscosity of the polymer of the two side components, because the polymer of the three components is pasted from the slit of the spinning hole in the form where the polymers of the three components are stuck at the inlet of the stock solution. When it is lower, there is a problem that a kneeling phenomenon occurs as in the case of using the above-mentioned spinneret and hollow cracks occur.

Further, in JP-A-59-192721, a core component having a low melt viscosity and a sheath component polymer having a high melt viscosity are arranged in a core-sheath shape and introduced into a spinning hole to obtain width, curvature and discontinuity. Disclosed is a method of obtaining hollow fibers having a high hollow ratio by utilizing the above-mentioned kneeling phenomenon by discharging while regulating the discharge amount from a discharge hole formed of an arc slit whose length is regulated. However, even if the fiber is spun by this method, the polymer is discharged in a form in which the core component and the sheath component are stuck together at the slit inner peripheral portion and the outer peripheral portion. When the difference in melt viscosity between the component polymers is large, the fibers have hollow cracks as described above, and there is a problem that the spinning operability also deteriorates.

[0006]

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. Even if the composite polymer is large, the core and the core using the spinneret capable of spinning the core-sheath hollow composite fiber that does not cause hollow cracks when discharged from the orifice composed of the slit, with good operability. It is a technical object to provide a method for producing a hollow-sheath composite fiber.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have considered the positions where the capillary discharge holes for discharging the core component and the slits of the orifices are arranged, In addition, when the core component polymer is wrapped in the sheath component polymer and the polymer is discharged from the orifice consisting of a slit, the knee-ring phenomenon does not occur, and the core-sheath hollow composite fiber without hollow cracks is runnable. They have found that they can be spun well and have reached the present invention.

That is, the gist of the present invention is as follows. In a spinneret for composite spinning of two different spinning component liquids A and B into a core-sheath type, a discharge guide hole for component A is provided in the upper part, and a composite flow introduction hole and a discontinuous part are provided in the lower part. A lower-end metal plate having an orifice composed of a slit,
It consists of a bottomed capillary for the B component and a capillary with a capillary discharge hole on the bottom, and an upper metal plate with a guide hole for the A component, and the capillary is closely inserted into the inner wall of the discharge guide hole for the A component which is a composite flow. A hollow-sheath composite fiber for a core-sheath, which has a notch serving as a passage for supplying the component A on the outer periphery of the capillary and has the following configurations (1) and (2): Spinneret. (1) The capillary discharge hole of the capillary is provided so as not to include the center point of the capillary between the center point of the capillary and the inner wall of the capillary guide hole, (2) there is no slit forming the orifice formed in the lower metal plate. The capillary discharge hole is arranged at a position outside the angle range K formed by both ends of the inner edge of the continuous portion and the center point of each space surrounded by the slit. A method for producing a hollow core-sheath composite fiber, which comprises using the spinneret described above when producing a core-sheath hollow composite fiber comprising two different spinning component liquids A and B by a composite spinning method.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a cross-sectional view (without cutting a capillary) showing an embodiment of the spinneret of the present invention, and FIG.
-X sectional view, FIG. 3 is a YY sectional view of FIG.
(A), (b), (c), and (d) are the inner edge ends of the discontinuous portion of the slit that constitutes the orifice punched in the lower metal plate of FIG. 1 and the center of each space surrounded by the slit. FIG. 5 is a schematic diagram showing an angle region K formed by a point, and FIG. 5 is a schematic sectional view of a core-sheath hollow composite fiber obtained by using the orifice shown in FIG.

FIG. 1 shows an example of a spinneret in which two capillary discharge holes are arranged at the central positions of two discontinuous slits as shown in the schematic view of FIG. 4 (a). A discharge guide hole 9 for the A component is provided on the upper portion of the lower metal plate 1, and an introduction hole 5 for combining the A component and the B component and an orifice for discharging the composite flow are provided on the lower portion of the discharge guide hole 9. 4 is drilled. The upper metal plate 2 has a bottomed capillary 3 having a capillary guide hole 7 for the B component and capillary discharge holes 6a and 6b, and a guide hole 11 for the A component communicating with the discharge guide hole 9 through a gap 10. In addition, the capillary 3 is closely inserted into the inner wall of the discharge guide hole 9 for the component A of the lower mouth plate 1. As shown in FIG. 2, a plurality of notches 8 serving as passages for supplying the A component are provided on the outer peripheral portion of the lower portion of the capillary 3.

In the spinneret for hollow core / sheath composite fibers of the present invention, the capillary discharge holes 6 (6a, 6b, ... 6n)
Is the center point M of the capillary 3 and the capillary guide hole 7
It is necessary to provide it so as not to include the center point M of the capillary 3 between the inner wall 13 and the inner wall 13. Furthermore, as shown in FIG.
Both ends of the inner edge of the discontinuous portion 12 of the slits (4a, 4b, ... 4n) forming the orifice 4 formed in the lower metal plate 1,
And the capillary discharge hole 6a at a position outside the angle range K formed by the center point P of each space surrounded by the slits.
It is necessary to arrange 6b, ..., 6n.

Thus, by disposing the capillary discharge hole 6 and the orifice 4 and providing the notch 8 on the outer peripheral portion of the capillary 3 as a passage for supplying the A component polymer, the polymer of the A component and the B component is separated. Without being discharged in a laminated form, B in the A component polymer
The component polymer is discharged in the form of islands, and the B component polymer is merged in the introduction hole 5 so as to be wrapped in the A component polymer to form a composite polymer. When the composite polymer is discharged from the slit of the orifice 4, the B component polymer does not exist in the slit discontinuity portion 12, so that the A component polymer discharged from the opposing slit ends causes a kneeling phenomenon. Previously, the bonding due to the ballast effect is facilitated, and a composite fiber without hollow cracks is obtained.

When the capillary discharge hole 6 includes the capillary center point M or exists in the angular range K, the B component polymer flows into the slit discontinuity portion 12, so that the compound discharged from the opposing slit ends. The polymer undergoes a kneeling phenomenon immediately after ejection, making it impossible to bond it to an adjacent polymer. Therefore, the obtained fiber becomes a bimetallic C-shaped yarn or flat yarn in which hollow cracking occurs, and the target core-sheath hollow composite fiber cannot be obtained.

In each constituent part of the core-sheath hollow composite fiber spinning die of the present invention, it is preferable that 3 to 20 notches 8 are provided practically, and the cross-sectional shape is circular or irregular.
It is not particularly limited. The cross-sectional shape of the capillary discharge hole 6 is not particularly limited to a circular shape, a polygonal shape, or any other irregular shape, and the number of the capillary discharge holes 6 and the cross-sectional area of the discharge holes are not limited to the polymer discharge amount, the polymer discharge amount, and the cross-sectional area. It may be appropriately selected depending on the melt viscosity.

The shape of the orifice 4 is shown in FIG.
As shown in the example of FIG.
a, 4b, ... 4n), and the hollow fiber is not particularly limited as long as a hollow fiber can be obtained from a single-component polymer. Therefore, when the spinneret for core-sheath hollow composite fiber of the present invention is used, It is possible to obtain a hollow composite fiber having one hollow portion (Figs. 4 (a) and 4 (b)) or a plurality of hollow portions (Figs. 4 (c) and 4 (d)), a hollow conjugate fiber having a modified cross section, and the like.

Next, a method for producing a hollow core-sheath composite fiber using the spinneret of the present invention will be described. First, the component A polymer is introduced through the guide hole 11 of the upper mouth plate 2. The introduced component A is introduced into the discharge guide hole 9 from the communicating gap 10 and then is quantitatively supplied to the introduction hole 5 from the wall surface side by the notch 8 of the capillary 3. On the other hand, the B component polymer is introduced from the upper end of the bottomed capillary 3, and the introduced B component passes through the capillary guide hole 7 and is arranged at a position not including the angular range K from the tip of the capillary guide hole 7. It is supplied quantitatively to the introduction hole 5 through the capillary discharge hole 6. At this time, the B component polymer is A
The composite polymer is a composite polymer in which both the components A and B join together in the form of being wrapped in the component polymer, and the composite polymer is extruded from the slits (4a, 4b, ... 4n) of the orifice 4 through the introduction hole 5. Then, the component A polymer extruded from the ends of the slits is bonded to each other to obtain a core-sheath hollow composite fiber having a hollow portion as shown in FIG.

According to the present invention, as described above, the B component polymer is merged so as to be wrapped in the A component polymer in the introduction hole 5 of the spinneret and is discharged from the orifice 4. It becomes difficult to be affected by the difference in melt viscosity of the component polymers, and good fibers free from hollow cracks can be obtained even when the A and B component polymers having a large difference in melt viscosity are combined and spun. Furthermore, either the A-component polymer as the sheath or the B-component polymer as the core may be the high melt viscosity polymer.

In the production method, the difference in melt viscosity between the A and B component polymers used is preferably 1200 poises or less, particularly preferably 700 poises or less, from the viewpoint of operability. In the composite spinning, the core / sheath weight ratio can be set to 5/95 to 95/5, but preferably,
It is 5/95 to 80/20, particularly preferably 10/90 to 75/25.

[0019]

EXAMPLES Next, the present invention will be specifically described by way of examples. In addition, the measuring method and evaluation of the characteristic value in an Example are as follows. (1) Melt viscosity (poise) 290 ℃ using a flow tester (CFT-500 manufactured by Shimadzu Corporation)
Was measured by the constant temperature method of ^1. and the value when the shear rate was 1000 sec ⁻¹ was taken as the measured value, and the measurement was performed 3 times and shown as the average value. The sample used was dried under reduced pressure at 120 ° C. for 5 hours. (2) Hollow ratio (%) The cross section of the single fiber of the yarn was measured by an image processing device using a microscope. The hollow ratio is calculated by the following formula, and the average value of the measured values of all the single fibers constituting the yarn (excluding the single fibers with hollow cracks) is calculated, and the average value of the number of spindles attached to the spinneret (below the decimal point) Rounded off). Hollow ratio (%) = (area of hollow part / area of whole single fiber) ×
100 (3) Hollow cracks (pieces) When measuring the hollow ratio, the number of single fibers with hollow cracks was measured. The measured values are shown by dividing the total number of hollow cracks generated in all spinnerets by the number of attached weights (rounded to the nearest whole number). (4) Spinning operability A spinneret was attached to four spinning spindles, spinning was continuously performed for 3 days, and the total number of yarn breakages at this time was evaluated by the following 3 ranks. A: 3 times or less ── Good B: 4 to 6 times ── Slightly bad C: 7 times or more ── Poor (5) Stretching operability The sum of the number of occurrences of stretch yarn breakage and roller single yarn winding is expressed by the number of spinning spindles. Calculate the 100-percentage of the divided value, and based on this value,
It was evaluated by rank. A: 1.5% or less ──Good B: 1.6 to 3.9% ──Slightly bad C: 4.0% or more ──Poor

Examples 1 to 5 Using a spinneret (FIG. 1) having 24 orifices having slits as shown in FIG. 4 (a), polyethylene terephthalate (titanium dioxide 0.5) having a melt viscosity of 2000 poise was used as a sheath component polymer. Wt%), polyethylene terephthalate was added and kneaded with 10 wt% of zirconium carbide (ZrC) as the core component polymer, and a polymer having a melt viscosity as shown in Table 1 was used, and the core / sheath weight ratio was 15/85. Total discharge
Melt-spinning was performed at a spinning temperature of 290 ° C. at 21.0 g / min, and wound at a speed of 1400 m / min. Subsequently, the undrawn yarn obtained was heated and drawn using a drawing roller at a temperature of 88 ° C. and a draw ratio of 2.74 times, and then heat-set using a heating plate at a heat treatment temperature of 160 ° C. at a speed of 700 m / min. It was wound up with 50 denier / 24 filament yarn. At this time, the spinning and drawing operability, the hollowness of the obtained fiber, and the evaluation of hollow cracks are shown in Table 1.
Shown in.

Comparative Examples 1 to 3 As a conventional core-sheath type spinneret, the spinneret shown in FIG. 1 was used, except that the capillary discharge hole 6 was opened at the center of the capillary guide hole 7 and melt spinning was performed. Was performed in the same manner as in Example 1. Table 1 shows the spinning and drawing operability at this time, the hollow ratio of the obtained fiber, and the evaluation of hollow cracks.

[0022]

[Table 1]

As is clear from Table 1, Examples 3 to 5 in which the difference in melt viscosity between the core component polymer and the sheath component polymer is 1200 poise or less are good in spinning and drawing operability, and the obtained yarns are There were no hollow cracks and the hollow ratio was high.
In Example 2 in which the difference in melt viscosity was more than 1300 poise, the drawing operability was slightly deteriorated, but the yarn obtained had no hollow cracks and a high hollow ratio. In Example 1 in which the difference in melt viscosity was close to 1700 poise, both spinning and drawing operability were slightly worse, but the same difference in melt viscosity was better than in Comparative Example 1 using the conventional core-sheath type spinneret and was satisfactory. It was at a level that could be achieved, and the obtained fiber also had a high hollow ratio. on the other hand,
Since Comparative Examples 1 to 3 were melt-spun using the conventional core-sheath type spinneret, the spinning and drawing operability were poor even when a polymer having a small difference in melt viscosity was used. Further, the obtained fibers became fibers with many hollow cracks, and in particular, in the fibers obtained in Comparative Examples 1 and 2 using polymers having a large difference in melt viscosity, hollow cracks occurred in all single yarns, and C-shaped It became a thread.

Examples 6 to 9 Polyethylene glycol (MW: 5800) was used as the core component polymer.
Example 2 was carried out in the same manner as in Example 1 except that polyethylene terephthalate having a melt viscosity of 1260 poise was copolymerized with 25% by weight) and the core / sheath weight ratio was changed as shown in Table 2. Table 2 shows the spinning and drawing operability, the hollowness of the obtained fiber, and the evaluation of hollow cracks at this time.

Comparative Examples 4 and 5, except that a conventional spinneret apparatus was used as in Comparative Example 1.
It carried out like Example 7 (comparative example 4) and Example 9 (comparative example 5). Table 2 shows the spinning and drawing operability, the hollowness of the obtained fiber, and the evaluation of hollow cracks at this time.

[0026]

[Table 2]

As is clear from Table 2, in Examples 6 to 9, good spinning and drawing operability were obtained, and a fiber having a high hollow ratio and no hollow crack could be obtained regardless of the core / sheath weight ratio. . On the other hand, in Comparative Examples 4 and 5, since melt spinning was performed using the conventional core-sheath type spinneret, spinning and drawing operability were poor, and the resulting fibers had many hollow cracks. In particular, Comparative Example 4 Then, in the obtained fiber, hollow cracks occurred in all single yarns and became C-shaped yarns.

[0028]

According to the present invention, even when a polymer having a large difference in melt viscosity is used for the core component and the sheath component, the composite polymer discharged from the slit of the orifice does not cause a kneeling phenomenon and is smoothly joined, It becomes possible to manufacture excellent quality core-sheath hollow composite fibers without hollow cracks with good operability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a spinneret for hollow-core composite fiber of the present invention (capillaries are not cut).

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view taken along line YY of FIG.

4 (a) to 4 (d) are made up of both ends of the inner edge of the discontinuous portion of the slit which constitutes the orifice punched in the lower metal plate of FIG. 1 and the center point of each space surrounded by the slit. It is a schematic diagram which shows the angle range K.

FIG. 5 is a schematic sectional view of a core-sheath hollow composite fiber obtained by spinning using the spinneret for core-sheath hollow composite fiber of the present invention having the orifice shown in FIG. 4 (a).

[Explanation of symbols]

 1 Lower mouth metal plate 2 Upper mouth metal plate 3 Capillary 4 Orifice 5 Introduction hole 6 Capillary discharge hole 7 Capillary guide hole 8 Notch 9 Discharge guide hole 10 Gap 11 Guide hole 12 Slit discontinuity 13 Capillary inner wall

Claims (2)

[Claims] 1. A spinneret for composite spinning of two different spinning component liquids A and B into a core-sheath type, which has a discharge guide hole for the component A in the upper part and an introduction hole for the composite flow in the lower part. A lower mouth metal plate having an orifice composed of a slit having a discontinuous portion, a capillary having a bottom for the B component and a capillary having a capillary discharge hole on the bottom surface, and an upper metal plate having a guide hole for the A component, A cap provided with a notch which is a closely-inserted capillary on the inner wall of the discharge guide hole for the component A, which is a composite flow, and is provided with a notch serving as a passage for supplying the component A on the outer periphery of the capillary, and (1) below, A spinneret for core-sheath hollow composite fibers, which has the configuration of (2). (1) The capillary discharge hole of the capillary is provided so as not to include the center point of the capillary between the center point of the capillary and the inner wall of the capillary guide hole, (2) there is no slit forming the orifice formed in the lower metal plate. The capillary discharge hole is arranged at a position outside the angle range K formed by both ends of the inner edge of the continuous portion and the center point of each space surrounded by the slit. 2. A hollow core / sheath composite fiber according to claim 1, which is used for producing a core / sheath hollow composite fiber composed of two different kinds of spinning component liquids A and B by a composite spinning method. Manufacturing method.