Spinneret

Abstract

To provide a spinneret free from polymer leakage, where many nozzle holes can be arranged, and having high productivity, by using a method for manufacturing a splittable rectangle spinneret by using a general purpose processor which can be introduced inexpensively.SOLUTION: A spinneret of the present invention has one or more distributor plates provided with a channel and a discharge plate arranged sequentially downstream in a polymer spinning direction and extends unidirectionally when observed from a polymer discharge face, wherein: at least on one face of one of the distributor plate or a laminate where two or more distributor plates are laminated is laminated with an assistance distributor plate with a hole extending in the polymer spinning direction to constitute a partial distributor plate; a plurality of partial distributor plates having a difference in thickness in the polymer spinning direction being 0.009 mm or under are arrayed in the extending direction of the spinneret; and the plurality of partial distributor plates are laminated with one distributor plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a spinneret and to a spinneret manufactured by the method. [Background technology]

[0002] A typical spinneret used to produce fiber webs has a rectangular shape extending in the long direction and is perforated with numerous nozzle holes. In recent years, efforts have been made to improve productivity by widening the spinneret itself. For example, Reifenhäuser (Germany), a major spunbond equipment manufacturer, released a 5.2-meter-wide spinning machine in April 2017, indicating that ultra-large spinnerets with a width of 3 meters or more are becoming mainstream.

[0003] In this context, manufacturing a very wide spinneret, such as one with a width of 3 m or more, requires an expensive long-length processing machine, resulting in high spinneret manufacturing costs. Furthermore, using such a long-length processing machine, it takes a very long time to manufacture a single spinneret. Therefore, spinnerets in which the spinneret extending in the width direction is divided into multiple pieces and then arranged are being studied. However, one problem with this approach is that the thickness of the divided spinnerets is not uniform, which raises concerns about polymer leakage. In particular, spinnerets for composite spinning using multiple polymer components are composed of multiple stacked plates. When divided, differences in plate thickness occur between the individual plates, making the concern of polymer leakage even more pronounced.

[0004] Therefore, Patent Document 1 discloses that, although the spinneret is not a long rectangular spinneret, the spinneret and the spinneret holder for holding the spinneret are divided into multiple pieces, and multiple members each consisting of the spinneret and the spinneret holder are arranged side by side. With this configuration, the spinneret can be assembled for each individual spinneret holder, and polymer leakage can be suppressed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-84303 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 discloses a method for solving the problem of polymer leakage by configuring a spinneret for each divided spinneret holder, as described above, but when this method is applied to a rectangular spinneret that produces a fiber web, the following problems 1) to 3) can occur. Note that when Patent Document 1 is applied to a rectangular spinneret, the spinneret holder corresponds to the discharge plate (the discharge plate has discharge holes drilled in its underside and discharges the polymer).

[0007] 1) A step occurs on the underside of the discharge plate, and when cleaning the nozzle (cleaning the discharge surface with a spatula), polymer accumulates on the step, causing thread breakage and reducing productivity.

[0008] 2) Because the discharge plate is divided, if even a small amount of polymer leaks, the polymer will accumulate on the discharge surface, causing thread breakage and reducing productivity.

[0009] 3) Because discharge holes cannot be placed near the dividing line of the discharge plate, the number of discharge holes that can be placed in the spinneret is reduced, resulting in lower productivity. In particular, when the outer periphery of the divided discharge plate is fastened with bolts, the number of discharge holes is reduced by the amount of space that is created. A spinneret for producing a fiber web has several thousand discharge holes arranged per meter of width, so if there is a large amount of space where discharge holes cannot be placed, the number of discharge holes is significantly reduced, resulting in a significant drop in productivity.

[0010] Furthermore, Patent Document 1 does not disclose a specific method for manufacturing the split die.

[0011] Therefore, the present invention provides a method for manufacturing a split-type rectangular spinneret using a general-purpose processing machine that can be introduced at low cost, a method for manufacturing a spinneret that is highly productive and does not leak polymer and can have a large number of discharge holes, and a spinneret manufactured by this method. [Means for solving the problem]

[0012] (1) The method for manufacturing a spinneret of the present invention that solves the above-mentioned problems is a method for manufacturing a spinneret in which one or more distribution plates and a discharge plate, each having a flow path formed therein, are arranged in this order toward the downstream side of the polymer spinning direction, and which extends in one direction when observed from the polymer discharge surface, a plurality of partial distribution plates each having an auxiliary distribution plate with a flow path extending in the polymer spinning direction superimposed on at least one surface of one of the distribution plates or a laminate of two or more of the distribution plates superimposed on one surface of the laminate; Next, at least one of the auxiliary distribution plates among the one or more partial distribution plates is subjected to a process for reducing the thickness thereof in the polymer spinning direction, so that the thicknesses of all the partial distribution plates in the polymer spinning direction are the same; Next, the plurality of partial distribution plates are arranged in the extending direction of the spinneret, Next, the discharge plate is placed on top of the aligned partial distribution plates.

[0013] (2) Another spinneret manufacturing method of the present invention that solves the above-mentioned problems is a method for manufacturing a spinneret in which one or more distribution plates and a discharge plate, each having a flow path formed therein, are arranged in this order toward the downstream side of the polymer spinning direction, and which extends in one direction when observed from the polymer discharge surface, a plurality of partial distribution plates each having an auxiliary distribution plate with a flow path extending in the polymer spinning direction superimposed on at least one surface of one of the distribution plates or a laminate of two or more of the distribution plates superimposed on one surface of the laminate; Next, the plurality of partial distribution plates are arranged in the extending direction of the spinneret, Next, at least one of the auxiliary distribution plates among the one or more partial distribution plates is subjected to a process for reducing the thickness thereof in the polymer spinning direction, so that the thicknesses of all the partial distribution plates in the polymer spinning direction are the same; Next, the discharge plate is placed on top of the aligned partial distribution plates.

[0014] The method for producing a spinneret of the present invention preferably satisfies at least one of the following (3) to (6). (3) The partial distribution plate is one of the distribution plates or a stack of two or more distribution plates, with the auxiliary distribution plates superimposed on both sides. (4) The auxiliary distribution plates on both sides of the partial distribution plate are processed to reduce their thickness in the polymer spinning direction. (5) The process for reducing the thickness in the direction of polymer spinning is grinding. (6) The distribution plate and the auxiliary distribution plate are joined together.

[0015] (7) A spinneret of the present invention that solves the above-mentioned problems is a spinneret in which one or more distribution plates and a discharge plate, each having a flow path formed therein, are arranged in this order toward the downstream side of the polymer spinning direction, and extend in one direction when observed from the polymer discharge surface, The partial distribution plate is formed by superimposing an auxiliary distribution plate having holes extending in the polymer spinning direction on at least one side of one of the distribution plates or a stack of two or more of the distribution plates, and multiple partial distribution plates having the same thickness in the polymer spinning direction are arranged side by side in the extension direction of the spinneret.

[0016] The spinneret of the present invention preferably satisfies the following (8) and / or (9). (8) The partial distribution plate is one of the distribution plates or a stack of two or more of the distribution plates, and the auxiliary distribution plates are stacked on both sides of the stack. (9) The distribution plate and the auxiliary distribution plate are joined together.

[0017] The meanings of the terms used in the present invention are listed below. "Polymer spinning direction" refers to the main direction in which the polymer exits the spinneret. The "long side direction" refers to the direction in which the sides of the approximately rectangular area in which a large number of nozzle holes are arranged on the discharge surface of the spinneret are longer. [Effects of the Invention]

[0018] According to the present invention, in a method for manufacturing a split rectangular spinneret using a general-purpose processing machine that can be introduced at low cost, it is possible to manufacture a spinneret that is free from polymer leakage, has a large number of discharge holes, and is highly productive. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic cross-sectional view of a spinneret according to the present invention. FIG. [Figure 2] FIG. 2 is a schematic cross-sectional view of a partial distribution plate according to an example of a process for producing the partial distribution plate that is a part of the spinneret of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The method for manufacturing a spinneret of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a schematic cross-sectional view of a spinneret of the present invention, and Fig. 2 shows an example of a process for manufacturing a partial distribution plate 5, which is a part of the spinneret. Note that these are conceptual diagrams that are simplified to accurately convey the gist of the present invention, and the number of spin blocks 4, the number of distribution plates 2, the number of partial distribution plates 5, the number of nozzle holes 8, and their dimensional ratios can be changed according to the embodiment.

[0021] As shown in Fig. 1, the spinneret 1 of the present invention has a rectangular shape extending in the long side direction, is fixed below the spin block 4 (downstream in the polymer spinning direction), and is composed of a plurality of partial distribution plates 5 arranged in the long side direction, and a discharge plate 3 located downstream in the polymer spinning direction from the partial distribution plates 5 and not divided in the long side direction. A flow path member such as a metering plate (not shown) may be inserted between the spin block 4 and the partial distribution plate 5. Furthermore, the discharge plate 3 is formed with nozzle holes 8 for discharging the polymer.

[0022] The partial distribution plate 5 is composed of a distribution plate 2 and two auxiliary distribution plates 6 arranged on both sides of the distribution plate 2 in the polymer spinning direction. As flow paths for passing the polymer, the distribution plate 2 has flow paths 9, and the auxiliary distribution plate 6 has flow paths 13. The auxiliary distribution plate 6 may be arranged on only one side of the distribution plate 2 in the polymer spinning direction. The distribution plate 2 may consist of a single plate, or two or more plates may be stacked. When two or more distribution plates 2 are stacked, the auxiliary distribution plate 6 is arranged on at least one side of the stack in the polymer spinning direction. The distribution plate 2 and the auxiliary distribution plate 6 are positioned with positioning pins so that their flow paths align, and may be fixed together with screws, bolts, etc., or may be welded, or may be metal-bonded (diffusion-bonded) by thermocompression bonding.

[0023] The polymer introduced into the spin block 4 passes through the flow paths 9 and 13 of the partial distribution plate 5, is introduced into the nozzle holes 8 of the discharge plate 3, and is discharged from the discharge surface 12. After that, it undergoes a cooling process (not shown) and is wound up as a yarn. Alternatively, it is spread over a collecting net to form a fiber web.

[0024] The spinneret 1 may be a spinneret for conjugate spinning using two or more component polymers, or a spinneret for single-component spinning using a single-component polymer. In the case of a spinneret 1 for conjugate spinning, since the polymer needs to be finely distributed, it is often configured by stacking multiple distribution plates 2. When multiple stacks of these distribution plates 2 are arranged in the long side direction, the difference in thickness between the individual distribution plates 2 becomes larger as the distribution plates 2 are stacked, and the difference in thickness between the individual stacks tends to become larger. Therefore, when manufacturing a spinneret for conjugate spinning, the spinneret manufacturing method of the present invention can be expected to have a more significant effect.

[0025] Next, the method for manufacturing the spinneret of the present invention will be described. The manufacturing method of the present invention involves the sequential four manufacturing steps shown in Figures 2(a) to 2(d).

[0026] First, as shown in Figure 2(a), multiple distribution plates 2 are produced, divided along the longitudinal direction. To precisely distribute the polymer, holes, grooves, or both holes and grooves are precisely machined into the distribution plates 2. The machining method can be drilling, precision metal machining using a lathe, machining, pressing, laser, electrical discharge machining, or etching. Alternatively, multiple distribution plates 2 can be stacked to form a single thick distribution plate. Because the total thickness error of the stacked distribution plates can be greater when multiple distribution plates 2 are used, the effect of improving polymer sealing properties achieved by the spinneret manufacturing method of the present invention is more pronounced. Note that the distribution plates 2 shown in Figure 2 are shown with significantly greater thickness differences than they actually are to facilitate understanding of the manufacturing process.

[0027] Next, as shown in Figure 2(b), auxiliary distribution plates 6 are layered on the top surface 10 and bottom surface 11 of the divided distribution plate 2. While it is preferable to layer auxiliary distribution plates 6 on both the top surface 10 and bottom surface 11 of the distribution plate 2, they may be layered on only one surface. Layering on one surface reduces processing costs. Layering on both surfaces reduces costs. In the next manufacturing process (Figure 2(c)), one surface is first ground to ensure a good surface condition without surface roughness or warping. This surface can then be used as a reference surface for grinding the auxiliary distribution plate 6 on the other side. This facilitates uniform processing of the thickness of the individually fabricated partial distribution plates 5 along the long side. The auxiliary distribution plate 6 has flow channels 13 that communicate with the flow channels 9 of the distribution plate 2. However, since the auxiliary distribution plate is ground in the next manufacturing process (Figure 2(c)), if the flow channels are made dense, the dimensions of the channels will change during the grinding process. Therefore, it is preferable that the flow paths 13 of the auxiliary distribution plate 6 are large-diameter flow paths that communicate with the multiple flow paths 9 of the distribution plate 2. Furthermore, in consideration of processing costs and delivery times, it is preferable that the number of flow paths 13 of the auxiliary distribution plate 6 be as small as possible.

[0028] Next, as shown in Figure 2(c), the auxiliary distribution plates 6 stacked on both sides of the partial distribution plate 5, i.e., on the upstream and downstream sides of the distribution plate 2 in the polymer spinning direction, are ground. It is preferable to grind multiple partial distribution plates 5 connected in the long side direction using a single grinding machine. This allows the thickness of the partial distribution plates 5 to be uniform. As mentioned above, grinding is the preferred method for achieving a uniform thickness of the partial distribution plate 5, but this is not the only option; etching, laser, or electrical discharge machining can also be used. Grinding the distribution plate 2 directly without stacking the auxiliary distribution plate 6 would change the dimensions of the flow channels 9 precisely machined in the distribution plate 2, potentially resulting in poor polymer distribution. Therefore, it is important to grind the auxiliary distribution plate 6 stacked on the distribution plate 2.

[0029] Next, as shown in Fig. 2(d), the partial distribution plates 5 ground in the previous manufacturing process are arranged consecutively in the long side direction. At this time, adjacent partial distribution plates 5 may be positioned with pins and fixed with screws, bolts, etc. Also, adjacent partial distribution plates 5 may be welded or metal-jointed at their dividing lines 7.

[0030] In addition, if the partial distribution plates 5 before being subjected to processing such as grinding can be arranged and fixed in the long side direction, and can be placed in a grinding machine or the like while still fixed, and processing can be performed to make the thickness of the partial distribution plates 5 uniform, the order of the steps in Figure 2(c) and Figure 2(d) above may be reversed.

[0031] As described above, by arranging the partial distributor plates 5 in the long-side direction instead of using a long distributor plate, the spinneret can be manufactured using a general-purpose processor that can be introduced at low cost, without requiring an expensive long-length processing machine. Furthermore, because the plate thickness between all partial distributor plates can be made the same, even when using a discharge plate 3 that is not divided in the long-side direction, polymer leakage, which is a major issue when a long distributor plate is divided, can be suppressed. Therefore, the reduced productivity of 1) and 2) in Patent Document 1 mentioned above can be avoided.

[0032] Furthermore, since there are no dividing lines on the discharge plate and there is no need to provide space for bolts within the approximately rectangular area in which many nozzle holes are arranged, there is no problem such as 3) in Patent Document 1 mentioned above, and since it is possible to arrange many nozzle holes, productivity can be improved. [Industrial Applicability]

[0033] The present invention is not limited to a method for manufacturing a spinneret used in a general melt spinning method, but can also be applied to a method for manufacturing a spinneret for passing a liquid other than a polymer, but the scope of application is not limited to these. [Example]

[0034] The present invention will be described in more detail below with reference to examples.

[0035] [Example 1] Five 11mm thick distributor plates were fabricated, measuring 600mm x 300mm when viewed from the polymer spinning direction. Five 21mm thick sub-distributor plates were fabricated by attaching a 5mm thick auxiliary distributor plate to both sides of each distributor plate. Because there was a manufacturing error in the thickness of each distributor plate and auxiliary distributor plate, the maximum thickness difference between the five sub-distributor plates fabricated was 0.193mm.

[0036] The five partial distribution plates were arranged in a single grinding machine, with the 600 mm side facing the long direction. The auxiliary distribution plates on each side were then ground down by 0.5 mm, with the goal of reducing the thickness of each partial distribution plate to 20 mm. The difference in thickness between the ground partial distribution plates was a negligible maximum of 0.009 mm, resulting in an almost uniform thickness for each partial distribution plate.

[0037] A spinneret was constructed by arranging five ground partial distribution plates, with a spin block that was not divided in the longitudinal direction attached to the upstream surface in the polymer spinning direction, and a discharge plate that was not divided in the longitudinal direction attached to the downstream surface in the polymer spinning direction. When polymer was introduced into this spinneret and the polymer flow was discharged from the nozzle holes, no polymer leakage was observed.

[0038] [Comparative Example 1] Five distribution plates were manufactured, each measuring 600mm x 300mm when viewed from the polymer spinning direction and 20mm thick. Because there was a manufacturing error in the thickness of each distribution plate, the maximum difference in thickness among the five partial distribution plates was 0.182mm.

[0039] The five fabricated distributor plates were lined up with the 600 mm side in the long direction, and a spin block that was not divided in the long side direction was attached to the upstream surface of the aligned distributor plates in the polymer spinning direction, and a discharge plate that was not divided in the long side direction was attached to the downstream surface in the polymer spinning direction to form a spinneret. When polymer was introduced into this spinneret and the polymer flow was discharged from the nozzle holes, polymer leakage occurred.

[0040] The results of Example 1 and Comparative Example 1 are summarized in Table 1.

[0041] [Table 1] [Explanation of symbols]

[0042] 1 spinneret 2 distribution plate 3 Discharge plate 4 Spin Block 5 Partial distribution plate 6 Auxiliary distribution plate 7. Dividing Line 8 nozzle holes 9 Flow path 10 Top surface 11 Bottom surface 12 Discharge surface 13 Flow path

Claims

1. A spinneret in which one or more distribution plates and a discharge plate, each having a flow path formed therein, are arranged in this order downstream in the polymer spinning direction, and extend in one direction when observed from the polymer discharge surface, a partial distribution plate in which an auxiliary distribution plate having holes extending in the polymer spinning direction is superimposed on at least one surface of one of the distribution plates or a stack in which two or more of the distribution plates are superimposed, and a plurality of partial distribution plates having a difference in thickness in the polymer spinning direction of 0.009 mm or less are aligned in the extension direction of the spinneret, A spinneret configured by stacking a plurality of partial distribution plates aligned in the extension direction on one discharge plate.

2. 2. The spinneret of claim 1, wherein the discharge plate has 1,000 or more discharge holes arranged per meter of width in the extension direction.

3. 3. The spinneret according to claim 1, wherein the partial distribution plate is one of the distribution plates or a stack of two or more distribution plates, and the auxiliary distribution plates are stacked on both sides of the stack.

4. The spinneret of any one of claims 1 to 3, wherein the distribution plate and the auxiliary distribution plate are joined together.

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