Composite nozzle and method for producing composite fiber

Abstract

Provided is a composite spinneret with which a polymer interface between polymers of different components can be gradually formed and high dimensional stability of the interface form can be maintained. This composite spinneret discharges a composite polymer fluid constituted of a polymer of two or more components. The composite spinneret has a bottom layer distribution plate in which there are formed a plurality of first discharge holes for discharging a first polymer component, and a plurality of second discharge holes for discharging a second polymer component different from the first polymer component. All the first discharge holes and second discharge holes that meet condition 1 satisfy condition 2.　Condition 1: The first discharge holes and the second discharge holes are located at an interface between the first polymer component and the second polymer component, within a range such as a straight line.　Condition 2: Any first discharge hole is denoted as a discharge hole 1a, the first discharge hole closest to the discharge hole 1a is denoted as a discharge hole 1b, the second discharge hole closest to the discharge hole 1a is denoted as a discharge hole 4b, and the second discharge hole closest to the discharge hole B is denoted as a discharge hole 4c. The distances between these discharge holes are predetermined distances.

Description

Technical Field

[0001] The present invention relates to a composite die and a method for manufacturing composite fibers using the same.

Background Art

[0002] As a method for manufacturing composite fibers, there is a composite spinning method using a composite die such as a core-sheath, side-by-side, or sea-island type die. In this method, the composite polymer flow is precisely controlled by the composite die, and a highly accurate yarn cross-sectional shape can be formed particularly in the running direction of the yarn. Here, as a method for manufacturing composite fibers by the composite spinning method, chips as raw materials are extruded by an extruder for each component to obtain a polymer, and the polymer is led to a spinning pack through a polymer pipe installed in a heating box. Then, each component polymer passes through a filter medium / filter disposed in the spinning pack to remove foreign substances, and is distributed by a perforated plate. Thereafter, each component polymer converges at the die to form a composite polymer flow, and a method of discharging from the final discharge hole of the die is adopted. The method for manufacturing composite fibers using this die is extremely important in determining the yarn cross-sectional shape.

[0003] Particularly in recent years, as a method for precisely controlling the yarn cross-sectional shape, a die called a distribution type die is used. In the distribution type die, a plurality of distribution plates are stacked to form a polymer flow path, and each component polymer is previously distributed into a large number by the distribution plates, and then discharged all at once from the lowermost distribution plate and combined to form a complex cross-section.

[0004] For example, Patent Document 1 discloses that in order to form various cross-sectional shapes with high precision, as the arrangement of the discharge holes of the two-component polymer (A / B component polymer) in the lowermost distribution plate, around the first discharge hole that discharges the A component polymer serving as the island component, in three directions, four directions, or six directions, by arranging the second discharge holes that discharge the B component polymer serving as the sea component, it is possible to manufacture a sea-island type composite fiber in which there is no confluence of the island components and the island components are polygonal. Also, by collecting the first discharge holes in the middle layer of the fiber cross-section and the second discharge holes in the outer layer, a core-sheath type composite fiber can also be manufactured. Furthermore, by collecting the first discharge holes in a star shape or a three-leaf shape, it is disclosed that a composite fiber with a star-shaped or three-leaf cross-section of the core component can be manufactured.

[0005] Also, as an example of the hole arrangement similar to that in Patent Document 1, Patent Document 2 discloses that by arranging in a hexagonal lattice pattern, a sea-island type composite fiber can be manufactured. Furthermore, Patent Document 3 discloses that by arranging around the discharge hole of either the A component or B component polymer, and alternately arranging the first discharge hole and the second discharge hole in the circumferential direction on the outer peripheral side thereof, a segmented type composite fiber can be manufactured.

[0006] Furthermore, a method for manufacturing a sea-island type composite fiber with a hole arrangement different from that in Patent Documents 1 and 2 using a distribution plate type die is disclosed in Patent Document 4. Patent Document 4 discloses various hole arrangements (arrangement of the first discharge hole for discharging the island component polymer and the second discharge hole for discharging the sea component polymer) as embodiments, and it is disclosed that a region containing only the sea component can be formed relatively freely among a large number of islands of the composite fiber. Furthermore, by discharging a core-sheath composite polymer in which the A component polymer is coated with the B component polymer from the first discharge hole and discharging the B component polymer from the second discharge hole, it is disclosed that a sea-island type composite fiber with a formed sea component region can be manufactured.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] However, the conventional methods for manufacturing composite fibers have the following technical problems. Patent Document 1 and Patent Document 2 do not describe the detailed arrangement of the discharge holes. Depending on the polymer combination and discharge conditions, the cross-sectional shapes of the island component and the core component may vary, and there is a possibility of improvement from the perspective of precisely controlling the desired cross-sectional form. That is, since the second discharge hole is arranged close to the first discharge hole of the lowermost layer distribution plate, the A-component polymer and the B-component polymer discharged from each discharge hole collide and merge in a state where the flow rates are high, and the interface between the A-component polymer and the B-component polymer may be disturbed, resulting in an unstable cross-sectional form. In particular, when the difference in the discharge amounts of the A-component polymer and the B-component polymer is large or when the difference in the polymer viscosities is large, the interface may become unstable.

[0009] Also, in the die disclosed in Patent Document 3, the first discharge hole and the second discharge hole of the lowermost layer distribution plate are alternately arranged in the circumferential direction. However, since the discharge holes for each polymer component are configured as single holes in order to form one interface, it may not be possible to precisely control the cross-sectional shape of the split fiber. In addition, since the discharge holes for each component are arranged close to each other, as described above, the interface between the polymers may be disturbed, resulting in an unstable cross-sectional form.

[0010] Furthermore, in the spinneret disclosed in Patent Document 4, it is possible to produce sea-island type composite fibers in which sea regions are formed relatively freely. However, according to the findings of the present inventors, since the distance between the first discharge holes (discharge holes for the island component polymer or the core-sheath composite polymer) and the second discharge holes (discharge holes for the sea component polymer) is close, the interface shape between the sea component polymer and the island component polymer becomes wavy under the influence of the arrangement of the discharge holes, and a desired fiber cross-section may not be obtained. When the interface becomes wavy, when dissolving the sea component polymer after manufacturing the composite fiber, the dissolving solution may not enter to the center of the composite fiber, resulting in poor dissolution. In addition, when a wavy shape remains in the fiber of the island component after dissolving the sea component polymer, the operability in the subsequent process may deteriorate, etc.

[0011] Therefore, the present invention provides a composite spinneret that solves the problems of the prior art, forms the cross-section of the composite fiber with high precision, and can maintain high stability of this cross-sectional form, and a method for manufacturing a composite fiber using the composite spinneret.

Means for Solving the Problems

[0012] [1] The present invention for solving the above problems is a composite spinneret that discharges a composite polymer stream composed of two or more polymer components, one or more distribution plates formed with distribution holes and / or distribution grooves for distributing each polymer component, a lowermost layer distribution plate disposed on the downstream side in the spinning path direction of the polymer of the distribution plate, having a plurality of first discharge holes for discharging a first polymer component and a plurality of second discharge holes for discharging a second polymer component different from the first polymer component, and a discharge plate disposed on the downstream side in the spinning path direction of the polymer of the lowermost layer distribution plate, having a spinneret discharge hole for forming a composite polymer stream in which the first polymer component and the second polymer component merge. In a cross-section perpendicular to the spinning path direction of the polymer in the composite polymer stream, the interface between the first polymer component and the second polymer component forms a straight line or a gentle curve, Among the first discharge holes and the second discharge holes, all the first discharge holes and the second discharge holes that meet the following condition 1 satisfy the following condition 2. Condition 1: In a cross-section perpendicular to the spinning path direction of the polymer in the composite polymer stream, between the first polymer component and the second polymer component straddling the interface are the first discharge hole and the second discharge hole that discharge the first polymer component and the second polymer component, respectively. Condition 2: Designate any one of the first discharge holes as discharge hole 1a, the first discharge hole adjacent to the discharge hole 1a with the shortest center-to-center distance as discharge hole 1b, the second discharge hole adjacent to the discharge hole 1a with the shortest center-to-center distance as discharge hole 4b, and the second discharge hole adjacent to the discharge hole 4b with the shortest center-to-center distance as discharge hole 4c. The center-to-center distance L between the discharge hole 1a and the discharge hole 4b AB is not less than twice the center-to-center distance L between the discharge hole 1a and the discharge hole 1b, and the center-to-center distance L between the discharge hole 4b and the discharge hole 4c A is not less than twice that. B Further, the composite die of the present invention is preferably the following [2] or [3]. [2] The composite die of [1] above, wherein all the first discharge holes corresponding to the above Condition 1 are arranged in a straight line or on a gentle curve, and all the second discharge holes corresponding to the above Condition 1 are arranged in a straight line or on a gentle curve. [3] The composite die of [1] or [2] above, wherein the first discharge holes and the second discharge holes corresponding to the above Condition 1 are arranged symmetrically with respect to the center line between the columns of the first discharge holes and the second discharge holes corresponding to the above Condition 1.

[0013] [4] The method for producing a composite fiber of the present invention produces a composite fiber by a composite spinning machine using any one of the composite dies of [1] to [3] above. Further, the method for producing a composite fiber of the present invention is preferably the following [5] or [6]. [5] The method for producing a composite fiber of [4] above, wherein the ratio of the discharge amount of the second polymer component discharged from one second discharge hole to the discharge amount of the first polymer component discharged from one first discharge hole is 0.3 or more and 3.3 or less. [6] The manufacturing method of the conjugate fiber according to [4] or [5] above, wherein the ratio of the melt viscosity of the first polymer component to the melt viscosity of the second polymer component is 0.2 or more and 5.0 or less.

[0014] In the present invention, the "distribution hole" refers to a hole formed by a combination of a plurality of distribution plates, which plays a role of distributing the polymer in the direction of the spinning path of the polymer. In the present invention, the "distribution groove" refers to a groove formed by a combination of a plurality of distribution plates, which plays a role of distributing the polymer in a direction perpendicular to the spinning path direction of the polymer. Here, the distribution groove may be an elongated hole (slit) or an elongated groove may be dug. In the present invention, the "spinning path direction of the polymer" refers to the main direction in which each polymer component flows from the distribution plate to the die discharge hole of the discharge plate. In the present invention, the "direction perpendicular to the spinning path direction of the polymer" refers to the direction perpendicular to the main direction in which each polymer component flows from the distribution plate to the die discharge hole of the discharge plate.

Advantages of the Invention

[0015] According to the conjugate die of the present invention, a polymer interface between different component polymers can be formed smoothly, and the dimensional stability of this interface morphology can be maintained at a high level. In addition, various fiber cross-sectional morphologies can be formed with high precision.

Brief Description of the Drawings

[0016]

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Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the composite die of the present invention will be described in detail with reference to the drawings. FIG. 2 is a schematic cross-sectional view of the composite die according to an embodiment of the present invention, and FIG. 4 is a view taken along the line X-X of FIG. 2. FIG. 1 is a partial enlarged plan view of the lowermost distribution plate used in the composite die of the embodiment of the present invention, and FIG. 6 is Partial enlarged plan view of the lowermost distribution plate according to another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a spin block using the composite die according to an embodiment of the present invention. Note that these are conceptual diagrams for accurately conveying the gist of the present invention, the figures are simplified, the composite die of the present invention is not particularly limited, and the number of holes and grooves and their dimensional ratios can be changed according to the embodiments.

[0018] As shown in FIG. 5, the composite spinneret 18 according to the embodiment of the present invention is equipped in the spinning pack 15, fixed in the spin block 16, and a cooling device 17 is configured directly below the composite spinneret 18. Therefore, the first polymer component guided to the composite spinneret 18 and at least one second polymer component different from the first polymer component each pass through the distribution plate 6 and the lowermost layer distribution plate 5, are discharged from the spinneret discharge holes 21 of the discharge plate 10, and then are cooled by the airflow blown out by the cooling device 17, are applied with an oil agent, and then are wound up as composite fibers. In FIG. 5, an annular cooling device 17 that blows out airflow in an annular and inward direction is adopted, but a cooling device 17 that blows out airflow from one direction may also be used. Further, regarding the members equipped on the upstream side of the distribution plate 6, the flow paths and the like used in the existing spinning pack 15 may be used, and there is no need for special specialization.

[0019] As shown in FIG. 2, the composite spinneret 18 used in the embodiment of the invention is configured by laminating at least one or more distribution plates 6, the lowermost layer distribution plate 5, and the discharge plate 10 in this order. In particular, it is preferable that the distribution plate 6 and the lowermost layer distribution plate 5 are configured of thin plates. In that case, the distribution plate 6, the lowermost layer distribution plate 5, and the discharge plate 10 may be positioned by positioning pins so that the center position (core) of the spinning pack 15 coincides, and after being laminated, they may be fixed with screws, bolts, etc., or may be metal-bonded by thermocompression bonding.

[0020] Therefore, as shown in FIG. 3, the first polymer component 13 supplied to the distribution plate 6 passes through the distribution grooves 8 and the distribution holes 7 of the distribution plate 6 laminated with at least one or more layers, and then is discharged from the first discharge hole 1 for discharging the first polymer component of the lowermost layer distribution plate 5. Although not shown, the second polymer component similarly passes through the distribution grooves 8 and the distribution holes 7 of the distribution plate 6 and is discharged from the second discharge hole 4 of the lowermost layer distribution plate 5. Inside the distribution plate 6 and the lowermost layer distribution plate 5, the first polymer component and the second polymer component do not merge and are distributed in their respective flow paths.

[0021] Then, as shown in FIG. 2, at the discharge introduction hole 11, the first polymer component discharged from the first discharge hole 1 and the second polymer component discharged from the second discharge hole 4 merge to form a composite polymer. Thereafter, the composite polymer is constricted at the constriction hole 12 and discharged from the die discharge hole 21. As shown in FIG. 4, one composite fiber is formed by discharging the composite polymer that has merged from the discharge holes of each component of the lowermost layer distribution plate 5 from the die discharge hole 21. The lowermost layer distribution plate 5 in FIG. 4 shows a schematic diagram of the formation of four composite fibers.

[0022] Here, the principle of forming the interface i between the first polymer component 13 and the second polymer component 14 into a straight line or a gentle curve in a cross-section perpendicular to the spinning path direction of the polymer in the composite polymer flow, which is an important point of the present invention, will be explained. Here, the "gentle curve" refers to an interface with an average deviation rate X calculated by the method described in "(1) Presence or absence of cross-sectional defects of composite fibers" in the examples being less than 30%. When forming the polymer interface of the composite polymer flow using the composite die of the conventional distribution type die, as shown in FIG. 11, the interface i between the first polymer component 13 and the second polymer component 14 becomes wavy, and since the composite polymer is discharged from the die discharge hole 21 as it is, a composite fiber with a distorted cross-sectional shape is formed. The reason for this will be explained using FIG. 9.

[0023] FIG. 9 shows the lowermost distribution plate 5' of the conventional example. At the boundary between the first polymer 13 and the second polymer 14, the first discharge holes 1 and the second discharge holes 4 are arranged in rows respectively. Among these discharge holes, any first discharge hole 1 is taken as the discharge hole 1(1a), the first discharge hole 1 adjacent to the discharge hole 1(1a) with the shortest center-to-center distance is taken as the discharge hole 1(1b), the second discharge hole 4 adjacent to the discharge hole 1(1a) with the shortest center-to-center distance is taken as the discharge hole 4(4b), and the second discharge hole 4 adjacent to the discharge hole 4(4b) with the shortest center-to-center distance is taken as the discharge hole 4(4c) for explanation. In the conventional example, since the discharge hole 1(1a) and the discharge hole 4(4b) are arranged very close to each other, before the first polymer components 13 discharged from the discharge holes 1(1a) and 1(1b) merge with each other, and before the second polymer components 14 discharged from the discharge holes 4(4b) and 4(4c) merge with each other, the first polymer component 13 discharged from the discharge hole 1(1a) merges with the second polymer component 14 discharged from the discharge hole 4(4b) closest to the discharge hole 1(1a). Therefore, the polymer interface is determined at the position where the first merger occurs. On the other hand, between adjacent discharge holes of the same polymer component (the discharge holes 1(1a) and 1(1b), the discharge holes 4(4b) and 4(4c)), since they merge later, a time difference occurs in the determination of the interface position. As a result, fluctuations occur in the polymer interface i, and it becomes difficult to form a smooth shape.

[0024] Therefore, in the dispensing die, appropriately arranging the discharge holes of each component of the lowermost distribution plate 5 and supplying an appropriate amount of polymer to form a composite polymer flow is an extremely important technique for manufacturing various forms of composite fibers. Therefore, the inventors of the present invention have conducted intensive studies on the above problems and as a result, have found a new technique of the present invention.

[0025] In the bottom layer distribution plate 5 of the embodiment of the present invention, as shown in FIG. 1, a plurality of first discharge holes 1 for discharging one type of polymer component (the first polymer component 13) and a polymer component different from the first polymer component (the second polymer component 14) A plurality of second discharge holes 4 for discharging are linearly arranged in rows respectively. Here, as in the description of the conventional example, any first discharge hole 1 is taken as the discharge hole 1(1a), and the first discharge hole 1 adjacent to this discharge hole 1(1a) at the shortest center-to-center distance is taken as the discharge hole 1(1b), and the second discharge hole 4 adjacent to the discharge hole 1(1a) at the shortest center-to-center distance is taken as the discharge hole 4(4b), and the second discharge hole 4 adjacent to this discharge hole 4(4b) at the shortest center-to-center distance is taken as the discharge hole 4(4c).

[0026] In the bottom layer distribution plate 5 of the embodiment of the present invention, in a cross section perpendicular to the polymer spinning path direction of the composite polymer flow, among the interfaces i between the first polymer component 13 and the second polymer component 14, the first polymer component 13 and the second polymer component 14 sandwiching the interface in the range forming a straight line or a gentle curve The first discharge hole 1 and the second discharge hole 4 for discharging each of them have a center-to-center distance L between the discharge hole 1(1a) and the discharge hole 4(4b). AB is more than twice the center-to-center distance L between the discharge hole 1(1a) and the discharge hole 1(1b), and the center-to-center distance L between the discharge hole 4(4b) and the discharge hole 4(4c). A is more than twice that, and is arranged so as to be more than twice the center-to-center distance L between the discharge hole 4(4b) and the discharge hole 4(4c). B That is, it is arranged so as to be more than twice the center-to-center distance L between the discharge hole 4(4b) and the discharge hole 4(4c).

[0027] Thus, in the bottom layer distribution plate 5 of the embodiment of the present invention, since the distance between the discharge hole 1(1a) and the adjacent discharge hole 4(4b) is arranged farther than that of the conventional bottom layer plate 5', the first polymer components 13 discharged from each of the discharge holes 1(1b) adjacent to the discharge hole 1(1a) merge, and further, after the second polymer components 14 discharged from each of the discharge holes 4(4c) adjacent to the discharge hole 4(4b) merge, the first polymer component 13 and the second polymer component 14 merge to form a composite polymer flow. As a result, it is possible to reduce the difference in the merging time due to the difference in the interface position, reduce the fluctuation of the interface i of the polymer, and form a gentle-shaped interface as shown in FIG. 10.

[0028] Here, the distance L AB is less than twice the distance L A Before the first polymer components 13 discharged from each of the discharge holes 1(1a) adjacent to the discharge hole 1 merge with each other, the first polymer component 13 discharged from the discharge hole 1(1a) and the second polymer component discharged from the adjacent discharge hole 4(4b) merge. Therefore, as described above, fluctuations may occur at the polymer interface, making it difficult to form a smooth interface shape. Similarly, when the distance L AB is less than twice the distance L B Before the second polymer components 14 discharged from each of the discharge holes 4(4b) adjacent to the discharge hole 4 merge with each other, the second polymer component discharged from the discharge hole 4(4b) and the first polymer component 13 discharged from the adjacent discharge hole 1(1a) merge. Therefore, fluctuations may occur at the polymer interface, making it difficult to form a smooth interface shape. For the sake of simplicity of explanation, in FIG. 1, the location of the reference discharge hole 1(1a) is defined for the explanation. However, in the lowermost layer distribution plate 5 of the embodiment of the present invention, any first discharge hole 1 arranged in a region where the interface between the first polymer component 13 and the second polymer component 14 is desired to be a straight line or a smooth curve can be used as the reference discharge hole 1(1a).

[0029] Also, in the lowermost layer distribution plate 5 of the embodiment of the present invention, at the interface i between the first polymer 13 and the second polymer 14, the first discharge holes 1 and the second discharge holes 4 are arranged in a row. The number of the first discharge holes 1 and the second discharge holes 4 arranged may be different, and the arrangement pitch of the first discharge holes 1 and the arrangement pitch of the second discharge holes 4 may be different. Preferably, by arranging the discharge holes in a one-to-one line-symmetric position with respect to the center line between the columns of the first discharge holes 1 and the second discharge holes 4 respectively, the distance L AB can be kept constant, so that the difference in the merging time within the column can be reduced.

[0030] Also, like the lowermost distribution plate 5A according to another embodiment of the present invention shown in FIG. 6, the first discharge hole 1 and the second discharge hole 4 may each form a column along a gentle curve. Thereby, the polymer interfaces of different components can form a gentle curve.

[0031] Figure 7 is, The present invention a form of a reference example not included in the lowermost distribution plate 5B according to is.

[0032] Next, a method for producing composite fibers using the composite die of the present invention will be described. For the method for producing composite fibers of the present invention, a known composite spinning machine may be used with the composite die 18 of the present invention. For example, in the case of melt spinning, the spinning temperature is set to be the temperature at which mainly high melting point or high viscosity polymers exhibit fluidity among two or more types of polymers. This temperature at which fluidity is exhibited varies depending on the molecular weight, but the melting point of the polymer serves as a reference, and it may be set at or below the melting point + 60°C. If it is below this temperature, the polymer is less likely to undergo thermal decomposition, etc. in the spinning pack 15, and the molecular weight reduction is suppressed, which is preferable. The spinning speed varies depending on the physical properties of the polymer and the purpose of the composite fiber, but is about 1 to 6000 m / min.

[0033] Also, the lowermost distribution plates 5, 5A of Preferably, the ratio of the discharge amount of the second polymer component 14 discharged from one second discharge hole 4 to the discharge amount of the first polymer component 13 discharged from one first discharge hole 1 is 0.3 or more and 3.3 or less. By setting this range, the interface between the first polymer component 13 and the second polymer component 14 is stabilized, and it becomes possible to maintain the shape accurately. When the ratio of the discharge amounts from each discharge hole is less than 0.3 or exceeds 3.3, the polymer component with the larger discharge amount will move the polymer component with the smaller discharge amount away from the position of the discharge hole, making it difficult to gently form the shape of the polymer interface.

[0034] Also, it is preferable that the ratio (=η1 / η2) of the melt viscosity η1 of the first polymer component to the melt viscosity η2 of the second polymer component used is 0.2 or more and 5.0 or less. By setting it within this range, the interface between the first polymer component and the second polymer component is stabilized and less likely to vary over time. If this ratio is less than 0.2 or exceeds 5.0, the polymer component on the low-viscosity side is likely to surround the polymer component on the high-viscosity side, making it difficult to form a smooth shape of the polymer interface.

[0035] Next, the composite fiber obtained by the composite die 18 of the present invention will be described. The composite fiber obtained by the composite die 18 of the present invention means a fiber in which two or more types of polymers are combined, and refers to a fiber in which two or more types of polymers exist in various island-like forms in the fiber cross-section. Here, two or more types of polymers include, for example, using two or more types of polymers having different molecular structures such as polyester, polyamide, polyphenylene sulfide, polyolefin, polyethylene, polypropylene, etc. Needless to say, within a range that does not impair the spinning stability, etc., various functional particles such as titanium dioxide and other matting agents, silicon oxide, kaolin, anti-coloring agents, stabilizers, antioxidants, deodorants, flame retardants, yarn friction reducers, coloring pigments, surface modifiers, etc. and additives such as organic compounds, differences in the addition amounts of particles, differences in molecular weights, or copolymerization, etc. are included.

[0036] Also, the cross-section of the single filament of the composite fiber obtained by the method for producing a composite fiber of the present invention may be not only round but also non-round shapes such as triangular and flat, or hollow. Further, the present invention is an invention with extremely high versatility and is not particularly limited by the single-filament fineness of the composite fiber, not particularly limited by the number of single filaments of the composite fiber, and furthermore, not particularly limited by the number of yarns of the composite fiber, and may be a single yarn or multiple yarns of two or more.

[0037] As described above, the composite fiber obtained by the method for producing a composite fiber of the present invention refers to a fiber in which two or more different types of polymers form various island shapes in a cross section perpendicular to the fiber axis direction. In that case, there is no restriction on the island shape. As in the case of the composite fiber 20 shown in Fig. 8(a), the interface between the second polymer component 14, which is a single flat island component, and the first polymer component 13 surrounding the second polymer component 14 may be linearly configured. Further, as in the case of the composite fiber 20A shown in Fig. 8(b), the interface of the second polymer component 14, which is an island component, may be configured in a gently curved shape. Furthermore, as in the case of the composite fiber 20B shown in Fig. 8(c), the interfaces of the second polymer component 14, which is a large number of flat island components, may be linearly configured. Still further, as in the case of the composite fiber 20C shown in Fig. 8(d), the second polymer component 14, which is a large number of island components, may have a complex shape, and a part of the interface thereof may be linearly configured. Regarding the number of these island shapes, theoretically, it is possible to produce an infinite number within the range allowed by the space of the discharge surface of the bottom layer distribution plate 5, but in a practically feasible range, 2 to 10,000 islands are preferably in the preferred range.

[0038] Next, FIGS. 1, 2, 3, 4, 5, 6 、 Each member and the shape of each member common to the composite die 18 of the embodiment of the present invention shown in Fig. 13 will be described in detail. The composite die 18 in the present invention is not limited to a circular shape, and may be square or polygonal. Further, the arrangement of the die discharge holes 21 in the composite die 18 may be appropriately determined according to the number of composite fibers, the number of yarns, and the cooling device 17. As the cooling device 17, in the case of an annular cooling device, it is preferable to arrange the die discharge holes 21 annularly in one row or multiple rows. In the case of a unidirectional cooling device, it is preferable to arrange the die discharge holes 21 in a lattice or staggered pattern.

[0039] The cross section of the die discharge hole 21 in a direction perpendicular to the spinning path direction of the polymer is not limited to a circular shape, and may have a cross section other than circular or a hollow cross section. However, when the cross section is other than circular, it is preferable to increase the length of the die discharge hole 21 in order to ensure the metering property of the polymer. In addition, the cross-section of the first discharge hole 1 and the second discharge hole 4 in the present invention in a direction perpendicular to the spinning path direction of the polymer is not limited to a circular shape, and may be an ellipse or a rectangle. In that case, taking the center of gravity of the discharge hole as center P, and with the center-to-center distance between the center Ps, the distance L A is calculated for the distance L AB and the distance L B .

[0040] In addition, for the flow reduction hole 12 in the present invention, by setting the reduction angle θ of the flow path from the discharge surface of the lowermost layer distribution plate 5 to the die discharge hole 21 in the range of 50 to 120°, unstable phenomena such as draw resonance of the composite polymer flow can be suppressed, and the composite polymer flow can be stably supplied. Here, when the reduction angle θ is less than 50°, the unstable phenomenon of the composite polymer flow can be suppressed, but the composite die 18 itself becomes larger. When the reduction angle θ is greater than 120°, the unstable phenomenon of the composite polymer flow may become more prominent.

[0041] In addition, the hole diameter of the opening above the flow reduction hole 12 is preferably larger than the outer diameter of the virtual circle 19 of the discharge hole group of the first discharge hole 1 and the second discharge hole 4 disposed on the discharge surface of the lowermost layer distribution plate 5, and the cross-sectional area ratio of the virtual circle 19 to the cross-sectional area of the discharge hole group is configured to be as small as possible. Thereby, the spread of each polymer discharged from the discharge surface can be suppressed, and the composite polymer flow can be stabilized.

[0042] In addition, only the distribution holes 7 may be provided on one distribution plate 6 of the present invention, only the distribution grooves 8 may be provided, or the distribution holes 7 may be provided on the upstream side of the distribution plate 6 and the distribution grooves 8 (downstream side) may be provided in communication therewith. Also, the distribution grooves 8 may be provided on the upstream side of the distribution plate 6 and the distribution holes 7 (downstream side) may be provided in communication therewith. In addition, the method for manufacturing the composite fiber of the present invention is not limited to the application of the melt spinning method, and can also be applied to the wet spinning method, the dry-wet spinning method, and the dry spinning method. When applying the wet spinning method, the composite die 18 is immersed in the coagulation bath, and when applying the dry spinning method, the composite die 18 is installed above the liquid level of the coagulation bath.

[0043] As described above, in the method for producing a composite fiber of the present invention, since the cross-sectional shape can be arbitrarily controlled, a free form can be produced without being restricted to the above forms. Further, the composite fiber produced by the production method of the present invention can be made into various fiber products such as fiber winding packages, tows, cut fibers, cotton, fiber balls, cords, piles, woven and knitted fabrics, non-woven fabrics, papers, and liquid dispersions.

Examples

[0044] The effects of the composite spinneret and the method for producing a composite fiber of the present invention will be specifically described with reference to the following examples. In each of the examples and comparative examples, a composite fiber was spun using the composite spinneret of the present invention, and the presence or absence of cross-sectional defects in the composite fiber was determined.

[0045] (1) Presence or absence of cross-sectional defects in the composite fiber Continuous spinning was performed for 24 hours from the start of spinning. Then, the obtained composite fiber was cut at an arbitrary position in the fiber axis direction, and the cross-section of the fiber was photographed at a magnification of 1000 times with a VE-7800 type scanning electron microscope (SEM) manufactured by Keyence Corporation. As shown in FIG. 12, among the interfaces between the first polymer component and the second polymer component, an average value line g in the range that is straight or curved is derived, and the average value line is divided into N = 49 equal parts (i = N + 1, i = 1, 2, 3 ··· N + 1), and the distance from the average value line at each divided position is Li (i = 1, 2, 3 ··· N + 1). Then, the average deviation η and the average deviation rate X are calculated by the following formulas. If the average deviation rate X is 30% or more, the cross-sectional shape is considered defective, and if it is less than 10%, the interface shape is considered good. Average deviation η = (L1 + L2 + L3 + ··· + L N+1 ) / (N + 1) Average deviation rate X [%] = average deviation η / outer diameter D of the composite fiber × 100

[0046] (2) Melt viscosity of the polymer The chip-shaped polymer was dried in a vacuum dryer to a moisture content of 200 ppm or less, and the melt viscosity was measured by gradually changing the strain rate with "Capillograph 1B" manufactured by Toyo Seiki. The measurement temperature was the same as the spinning temperature, and the melt viscosity at 1216 s was described in the examples or comparative examples. Incidentally, the time from when the sample was put into the heating furnace until the start of measurement was 5 minutes, and the measurement was carried out under a nitrogen atmosphere. -1 The melt viscosity of -1 was described. Incidentally, the time from when the sample was put into the heating furnace until the start of measurement was 5 minutes, and the measurement was carried out under a nitrogen atmosphere.

[0047] (3) Intrinsic viscosity [η] It was measured at 25 °C using orthochlorophenol as a solvent.

[0048] (4) Relative viscosity in 98% sulfuric acid [ηr] (a) Weigh the sample and dissolve it in 98% mass-concentrated sulfuric acid so that the sample viscosity C is 1 g / 100 ml. (b) Measure the drop time T1 at 25 °C for the solution in item (a) using an Ostwald viscometer. (c) Measure the drop time T2 at 25 °C for the 98% mass-concentrated sulfuric acid without dissolving the sample. (d) Calculate the relative viscosity ηr of the sample in 98% sulfuric acid using the following formula. The measurement temperature is 25 °C. ηr = (T1 / T2) + {1.891×(1.000 - C)}

[0049] [Example 1] As the first polymer component, polyethylene terephthalate (PET) with an intrinsic viscosity [η] of 0.65 and a melt viscosity of 210 Pa·s, and as the second polymer component, polyethylene terephthalate (PET) with an intrinsic viscosity [η] of 0.59 and a melt viscosity of 130 Pa·s were separately melted at 285°C. These melted polymers were discharged from one die orifice 21 using the following coextrusion die 18 at a ratio of the total discharge amount of the first polymer component / the total discharge amount of the second polymer component of 15 / 85 (≈0.18). The discharged polymer was cooled by a cooling device 17, and then oiling, entanglement treatment, and hot stretching were performed, and it was wound up at a speed of 1500 m / min by a winding roller to collect an undrawn fiber of 168 dtex - 18 filaments (single orifice discharge amount 4 g / min). The wound undrawn fiber was stretched 3.0 times between rollers heated to 90°C and 130°C to collect a composite fiber of 56 dtex - 18 filaments. As shown in Fig. 8(a), the cross-section of the composite fiber had a single-letter-shaped cross-sectional form. Here, as shown in Fig. 1, on the lowermost layer distribution plate 5 of the coextrusion die 18 used in Example 1, in the range where the interface between the first polymer component and the second polymer component of the composite polymer flow is made straight (the range forming the long side of a single letter), a first discharge hole 1 for discharging each of the first polymer component and the second polymer component and a second discharge hole 4 are arranged. The number of holes of the first discharge hole 1 per one composite fiber is 40 holes, and the number of holes of the second discharge hole 4 is 30 holes. These discharge holes form a straight line, and the first discharge hole 1 and the second discharge hole 4 are arranged symmetrically with respect to the center line between each row. And the center-to-center distance L A is 1 mm, the center-to-center distance L B is 1 mm, the center-to-center distance L AB is 2.5 mm, and the center-to-center distance L AB is 2.5 times the center-to-center distance L A and the center-to-center distance L AB is the center-to-center distance L BIt is arranged to be 2.5 times. As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section is 1.3%, there is no cross-section defect, and the result is good. The ratio of the discharge amount of the second polymer component discharged from one second discharge hole 4 to the discharge amount of the first polymer component discharged from one first discharge hole 1 was about 0.13.

[0050] [Example 2] Composite fibers were collected using the same composite die 18, polymers, and spinning conditions as in Example 1, except that the ratio of the total discharge amount of the first polymer component / the total discharge amount of the second polymer component discharged from one die discharge hole 21 was changed to 35 / 65 (≈0.54). As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section is 1.0%, there is no cross-section defect, and the result is good. The ratio of the discharge amount of the second polymer component discharged from one second discharge hole 4 to the discharge amount of the first polymer component discharged from one first discharge hole 1 was about 0.40. [Example 3] The lowermost layer distribution plate 5 was changed, and elliptical composite fibers as shown in Fig. 8(b) were collected using the same polymers and spinning conditions as in Example 1, except that the ratio of the total discharge amount of the first polymer component / the total discharge amount of the second polymer component discharged from one die discharge hole 21 was changed to 25 / 75 (≈0.33). In the lowermost layer distribution plate 5 of the composite die 18, as shown in Fig. 6, in the range forming the long side of the elliptical shape, the first discharge hole 1 and the second discharge hole 4 are arranged as a row so as to form a gentle curve. The number of holes of the first discharge hole 1 per one composite fiber is 40, and the number of holes of the second discharge hole 4 is 30. And the center distance L A is 1 mm, the center distance L B is 1 mm, the center distance L AB is 2.3 mm, and the center distance L AB is 2.3 times the center distance L A , and the center distance LAB is the center distance L BIt is arranged to be 2.3 times that. As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section is 1.8%, there is no cross-section defect, and good results are obtained. The ratio of the discharge amount of the second polymer component discharged from one second discharge hole 4 to the discharge amount of the first polymer component discharged from one first discharge hole 1 was about 0.25.

[0051] [Example 4] Except for changing the lowermost layer distribution plate 5, using the same polymer and spinning conditions as in Example 1, a composite fiber with a single-character cross-sectional shape as shown in Fig. 8(a) was collected. In the lowermost layer distribution plate 5C of the composite die 18, as shown in Fig. 13, in the range forming the long side of the single-character shape, all of either the first discharge hole 1 or the second discharge hole 4 are arranged in the long direction of the single-character shape, with the center-to-center distance L A moved by half of the distance, and arranged in a staggered pattern. The number of holes of the first discharge hole 1 per composite fiber is 40, and the number of holes of the second discharge hole 4 is 30. And the center-to-center distance L A is 1 mm, the center-to-center distance L B is 1 mm, the center-to-center distance L AB is 2.6 mm, and the center-to-center distance L AB is 2.6 times the center-to-center distance L A is 2.6 times the center-to-center distance L AB is arranged to be 2.6 times the center-to-center distance L B As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section is 2.9%, there is no cross-section defect, and good results are obtained. The ratio of the discharge amount of the second polymer component discharged from one second discharge hole 4 to the discharge amount of the first polymer component discharged from one first discharge hole 1 was about 0.13.

[0052] [Comparative Example 1] Using the same composite die 18 as in Example 1, except that the arrangement of the discharge holes of the lowermost layer distribution plate 5 is different, spinning was carried out with the same polymer, the same fineness, and spinning conditions as in Example 1. The first discharge hole 1 and the second discharge hole 4 of the lowermost layer distribution plate 5 have a center-to-center distance L A of 1 mm, the center-to-center distance L B of 1 mm, the center-to-center distance L AB of 1.5 mm, and the center-to-center distance LAB is the center-to-center distance L A is 1.5 times the center-to-center distance L AB is the center-to-center distance L B are arranged such that it is 1.5 times the center-to-center distance L. As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section was 15%, resulting in cross-section defects.

[0053] [Comparative Example 2] Using the same composite die 18 as in Example 1, except that the arrangement of the discharge holes of the lowermost layer distribution plate 5 is different, spinning was carried out with the same polymer, the same fineness, and spinning conditions as in Example 1. The first discharge hole 1 and the second discharge hole 4 of the lowermost layer distribution plate 5 have a center-to-center distance L A of 1 mm, the center-to-center distance L B of 1 mm, the center-to-center distance L AB of 1 mm, the center-to-center distance L AB is the center-to-center distance L A is 1.0 times the center-to-center distance L AB is the center-to-center distance L B are arranged such that it is 1.0 times the center-to-center distance L. As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section was 35%, resulting in cross-section defects.

[0054] [Comparative Example 3] Using the same composite die 18 as in Example 1, except that the lowermost layer distribution plate 5C was used, spinning was carried out with the same polymer, the same fineness, and spinning conditions as in Example 1. The lowermost layer distribution plate 5C is arranged in a staggered arrangement equivalent to that in Example 3. The number of holes of the first discharge hole 1 per composite fiber is 40 holes, and the number of holes of the second discharge hole 4 is 30 holes. The first discharge hole 1 and the second discharge hole 4 of the lowermost layer distribution plate 5C have a center-to-center distance L A of 1 mm, the center-to-center distance L B of 1 mm, the center-to-center distance L AB of 1.6 mm, the center-to-center distance L AB is the center-to-center distance L A is 1.6 times the center-to-center distance L AB is the center-to-center distance L BIt is arranged to be 1.6 times that. As shown in Table 1, the average deviation rate of the interface shape of the fiber cross-section is 18%, resulting in cross-section defects. The ratio of the discharge amount of the second polymer component discharged from one second discharge hole 4 to the discharge amount of the first polymer component discharged from one first discharge hole 1 was about 0.13. The results of each example and comparative example are summarized in Table 1.

[0055]

Table 1

Industrial Applicability

[0056] The present invention is not limited to the composite spinneret used in the general solution spinning method, but can be applied to the melt blowing method and the spunbond method, and can also be applied to the spinnerets used in the wet spinning method and the dry-wet spinning method, but the scope of its application is not limited to these.

Explanation of Reference Numerals

[0057] 1 First discharge hole 1a Arbitrary first discharge hole 1b First discharge hole adjacent to discharge hole 1a with the shortest center-to-center distance 4b Second discharge hole adjacent to discharge hole 1a with the shortest center-to-center distance 4c Second discharge hole adjacent to discharge hole 4b with the shortest center-to-center distance 4 Second discharge hole 5, 5A, 5B, 5C, 5’ Lowermost layer distribution plate 6 Distribution plate 7 Distribution hole 8 Distribution groove 10 Discharge plate 11 Discharge introduction hole 12 Flow contraction hole 13 First polymer component 14 Second polymer component 15 Spinning pack 16 Spin block 17 Cooling device 18 Composite spinneret 19 Virtual circle 20, 20A, 20B, 20C Composite fiber 21 Nozzle discharge hole

Claims

1. A composite spinneret for discharging a composite polymer stream composed of two or more component polymers, one or more distribution plates having distribution holes and / or distribution grooves for distributing each polymer component; a lowermost distribution plate disposed downstream of the distribution plate in a polymer spinning path direction, the lowermost distribution plate having a plurality of first discharge holes for discharging a first polymer component and a plurality of second discharge holes for discharging a second polymer component different from the first polymer component; a discharge plate disposed downstream of the lowermost distribution plate in a direction of a polymer spinning path, the discharge plate having a spinneret discharge hole for forming a composite polymer stream in which the first polymer component and the second polymer component are joined together, In a cross section of the composite polymer stream perpendicular to a polymer spinning path direction, an interface between the first polymer component and the second polymer component forms a straight line or a gentle curve; A composite spinneret, wherein all of the first discharge holes and the second discharge holes that meet the following condition 1 satisfy the following condition 2. Condition 1: In a cross section perpendicular to the polymer spinning path direction of the composite polymer stream, the first and second discharge holes discharge the first and second polymer components, respectively, sandwiching the interface between the first and second polymer components. Condition 2: Any of the first discharge holes is defined as discharge hole 1a, the first discharge hole adjacent to the first discharge hole 1a at the shortest center-to-center distance is defined as discharge hole 1b, the second discharge hole adjacent to the discharge hole 1a at the shortest center-to-center distance is defined as discharge hole 4b, and the second discharge hole adjacent to the discharge hole 4b at the shortest center-to-center distance is defined as discharge hole 4c. The center-to-center distance L between the discharge hole 1a and the discharge hole 4b is defined as ＡＢ The center distance L between the discharge holes 1a and 1b is Ａ and the center-to-center distance L between the discharge holes 4b and 4c is equal to or more than twice the center-to-center distance L between the discharge holes 4b and 4c. Ｂ This is more than twice as much.

2. 2. The composite spinneret according to claim 1, wherein all of the first discharge holes which satisfy the condition 1 are arranged so as to be aligned on a straight line or a gentle curve, and all of the second discharge holes which satisfy the condition 1 are arranged so as to be aligned on a straight line or a gentle curve.

3. 3. The composite spinneret according to claim 2, wherein the first discharge holes and the second discharge holes which satisfy the condition 1 are arranged in line-symmetrical positions across a center line between the rows of the first discharge holes and the rows of the second discharge holes which satisfy the condition 1.

4. A method for producing a composite fiber, comprising producing a composite fiber by a composite spinning machine using the composite spinneret according to any one of claims 1 to 3.

5. 5. The method for producing a composite fiber according to claim 4, wherein a ratio of an amount of the second polymer component discharged from one of the second nozzle holes to an amount of the first polymer component discharged from one of the first nozzle holes is 0.3 or more and 3.3 or less.

6. 5. The method for producing a composite fiber according to claim 4, wherein a ratio of a melt viscosity of the first polymer component to a melt viscosity of the second polymer component is 0.2 or more and 5.0 or less.

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