JP4990192B2 - Method for producing hollow fiber continuum - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a continuous hollow strand preventing the defects such as the deficient joint strength of a joint part of the hollow strand and the increased diameter, and preventing the lowering of process stability in the production and processing of a hollow fiber membrane. <P>SOLUTION: The method for the production of a continuous hollow strand includes a step to arrange a pair of hollow strands 3a, 3b in a manner that the end parts 3c, 3d in the range of &le;150 mm from one end toward the center are positioned in parallel adjacent to each other, and a step to weld the whole end parts of the pair of adjacent hollow strands 3a, 3b by compressing and deforming the end parts 3a, 3b in a mutually overlapped state. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a continuous hollow fiber article used for a support for producing a hollow fiber membrane.

In recent years, interest in environmental pollution has increased, and various environmental laws have been strengthened, and countermeasures are being promoted in various fields. For example, in the field of water treatment, treatment using a small filtration membrane is being studied in order to highly separate contaminants.
By the way, when using a filtration membrane for water treatment, high mechanical properties (for example, pressure resistance, tensile strength, etc.) are required. As a method for producing a porous filtration membrane excellent in mechanical strength, a method for producing a hollow fiber membrane using a hollow round braid as a hollow fiber membrane support has been proposed (Patent Documents 1, 2, 3). Specifically, in this production method, a hollow fiber membrane support is fed from the center hole of the annular nozzle, and a membrane-forming stock solution spun from the outer periphery of the annular nozzle is formed on the outer periphery of the hollow fiber membrane support. It is applied and solidified to obtain a hollow fiber membrane.
In the above production method, in order to obtain a long hollow fiber membrane, the hollow fiber membrane support also needs to be long. Usually, the length of the hollow fiber membrane support is the length of the hollow fiber membrane. Since it is shorter than the desired length, a plurality of supports must be connected.

As a method for connecting the hollow fiber articles, for example, a method using a known splicer is known.
However, in the connection method using a splicer, since a skillful technique is required, it is often impossible to connect appropriately. Here, when the hollow fiber membrane supports are not properly connected to each other, problems such as insufficient connection strength and an increase in the diameter of the connection portion occur. When such a problem occurs, the hollow fiber membrane support may be clogged or caught in the center hole of the annular nozzle whose outer diameter is regulated by the connecting portion of the hollow fiber membrane support. . Therefore, there is a possibility that the stability of the process for producing or processing the hollow fiber membrane is lowered.

By the way, various methods have been proposed so far for solid string connection methods. For example, Patent Document 4 discloses that a plastic round string is overlapped or twisted in parallel, and partially heat-pressed at regular intervals to alternately form heat-bonded portions and non-heat-bonded portions. There has been proposed a method of joining the two.
However, when the connection method described in Patent Document 4 is applied to the hollow fiber article, the diameter of the heat-sealed portion is slightly smaller than the combined diameter of the two hollow fiber articles. In addition, the diameter of the non-heat-sealed portion is a size obtained by combining two hollow yarns. Therefore, in the connection method described in Patent Document 4, since the connection is not performed so that a step is not formed on the side surface after connection, the obtained continuous body is a portion in which the outer diameter is regulated, such as the center hole of the annular nozzle. When it is passed through, it may be clogged or caught, which may reduce the stability of the process for producing or processing the hollow fiber membrane.

In addition, a method has been proposed in which after knitting an elastic string body, the stitches are folded and overlapped, and fused by ultrasonic vibration or heating (see Patent Document 5). However, the fusion in Patent Document 5 does not connect two yarns to obtain one continuous body. In addition, since the object to be fused is a solid string body, it is considered that the volume of the overlapped portion is small in volume change before and after the fusion, and either of the side surfaces after the connection There is a high possibility that a step is formed in the portion, and the invention described in Patent Document 5 has no concept of preventing the step from being formed on the side surface after connection.
Japanese Patent Laid-Open No. 52-81076 JP-A-5-7746 WO04 / 43579 pamphlet Japanese Patent Laid-Open No. 50-4358 Japanese Patent No. 2962243

  The object of the present invention is to prevent hollow fiber filaments from being inadequate in connection strength and increasing their diameter, and to prevent hollow fiber filaments from being deteriorated in process stability during the production and processing of hollow fiber membranes. It is providing the manufacturing method of the hollow fiber continuous article which can manufacture a body.

The present invention includes the following aspects.
[1] A step of arranging a pair of hollow fibers so that the ends are adjacent in parallel;
And a step of fusion-bonding the entire ends of a pair of adjacent hollow yarn articles while compressively deforming the ends so that the ends overlap each other. Method.
[2] The method for producing a continuous hollow fiber article according to [1], wherein the end portion is in a range of 150 mm or less from one end face toward the center.
[3] A method for producing a continuous hollow fiber article, comprising a step of subjecting the ends of a pair of hollow fiber articles to ultrasonic fusion treatment.

  According to the method for producing a continuous hollow fiber article of the present invention, it is possible to prevent problems such as insufficient connection strength and an increase in diameter of the connection part of the hollow fiber article, and process stability during the production and processing of the hollow fiber membrane. It is possible to produce a continuous hollow fiber article in which the decrease is prevented.

One embodiment of the method for producing a continuous hollow fiber article of the present invention will be described.
In the method for producing a continuous hollow fiber article of the present embodiment, a pair of hollow fiber articles are arranged adjacent to each other so that the ends thereof are adjacent in parallel (hereinafter referred to as an adjacent arrangement process). A step of performing ultrasonic fusion treatment (hereinafter referred to as a fusion step) while compressing and deforming the entire ends of the pair of hollow fiber articles so that the ends overlap each other.
Here, the end portion refers to a portion of the hollow fiber article in a range of 150 mm or less from one end face toward the center. When hollow fiber articles are connected to each other at a portion in a range exceeding 150 mm from one end surface toward the center, there is a high possibility that the connection itself is not simple.

[Adjacent placement process]
In the adjacent arrangement step, a length for adjoining the ends of the pair of hollow filaments in parallel (hereinafter referred to as a parallel length) is appropriately selected according to desired connection strength and flexibility after connection. Although it is not particularly limited, considering the stability when the obtained hollow fiber continuum is repeatedly used, (parallel length A) / (outer diameter d ₁ or d _{2 of} hollow fiber ) Is preferably 1 or more.
In addition, if the parallel length A is long, the flexibility is lowered, the force required for deforming the hollow fiber at the time of connection becomes large, or the ultrasonic fusion device becomes large. The parallel length A is preferably 40 mm or less.
Furthermore, in the adjacent arrangement step, a continuous hollow fiber article without a step on the side surface can be easily manufactured, so that the axis of the end of each hollow fiber article may be on the same straight line along the vertical direction. preferable.

The shape of the cross section perpendicular to the length direction of the hollow fiber article in this embodiment is a substantially circular shape. The outer diameter of the hollow fiber is not particularly limited, but is preferably 1 to 5 mm.
Here, the hollow yarn is a yarn having a space portion continuous along the longitudinal direction. There are at least one or more space portions in the yarn, and when there are a plurality of the space portions, each space portion may be independent or in communication.
Specific examples of the hollow yarn include a hollow fiber, a hollow braid, a hollow knitted string, and a hollow fiber membrane.

The material of the hollow fiber is not particularly limited as long as it can be fused and used for synthetic fibers and separation membranes. For example, polyethylene terephthalate, nylon, polyethylene, polypropylene, poly Examples include vinyl chloride, polysulfone, polyacrylonitrile, cellulose acetate, and polyvinylidene fluoride. These may be used alone or in combination.
The pair of hollow fiber articles may be the same or different.

[Fusion process]
In the fusing process of the present embodiment example, as shown in FIGS. 1 and 2, in order to compress and deform the entire ends of a pair of adjacent hollow fiber articles so that the ends overlap each other. A connection device including an ultrasonic horn 1 and a connection jig 2 is used.
The ultrasonic horn 1 of the present embodiment has a lower surface 1a that is in contact with the hollow fiber 3b, and transmits ultrasonic waves from the lower surface to the hollow fiber 3a, 3b.
The connection jig 2 of the present embodiment is a rectangular plate, and a groove 2a is formed linearly from one side of the plate toward the side opposite to the side, and the depth of the groove 2a is a pair of The hollow fiber articles 3a and 3b can be stacked and stored.
In the fusion using the ultrasonic horn 1 and the connection jig 2 described above, as shown in FIG. 3, the end portions 3c and 3d of the hollow fiber article are respectively inserted into the grooves 2a of the connection jig 2, and then FIG. As shown in FIG. 2, the end of the ultrasonic horn 1 is inserted into the groove 2a, the end portions 3c and 3d are pressed against the bottom of the groove 2a, and the adjacent hollow fiber articles 3a so that the end portions 3c and 3d overlap each other. , 3b is compressed and deformed. Then, while maintaining the compression deformation state, ultrasonic waves are transmitted from the ultrasonic horn 1 to the end portions 3c and 3d of the adjacent hollow fiber articles 3a and 3b to be fused.
When the hollow yarns 3a and 3b are fused together using the ultrasonic horn 1, the hollow yarns 3a and 3b are locally heated due to friction to deform the bonded portion. A liquid such as water may be present between the fibers of the objects 3a and 3b, the porous portion, and the like, and may be wet.

In this compression deformation, since the process stability of the resulting hollow fiber continuum is higher, the portion where the ends of the pair of hollow fiber products overlap after compression deformation is perpendicular to the length direction. The cross-sectional shape (hereinafter referred to as the cross-sectional shape) is preferably substantially the same as the cross-sectional shape of one hollow fiber before compression deformation, that is, substantially circular.
In order to make the cross-sectional shape of the portion where the ends of the pair of hollow fiber articles overlap after compression deformation substantially the same as the cross-sectional shape of one hollow fiber object before compression deformation, for example, FIG. As shown in FIG. 1, it is possible to employ a method in which an ultrasonic horn 1 having a groove recessed in an arc shape is formed on the lower surface 1a and a connection jig 2 having a U-shaped groove 2a is used. When the ultrasonic horn 1 is inserted into the groove 2a of the connecting jig 2, a hollow portion having a substantially circular cross section is formed.
When the connection jig 2 and the ultrasonic horn 1 are used, a minute gap is generated between them, and a burr-like thing may be formed after ultrasonic fusion. A burr-like thing may be generated.

  When the ultrasonic horn 1 and the connection jig 2 are used, the end portions 3c and 3d of the adjacent hollow fiber articles 3a and 3b can be fused at a time. A desired connection strength can be more easily obtained by fusing the end portions 3c and 3d of the adjacent hollow fiber articles 3a and 3b at a time.

  The thrust (surface pressure) and the ultrasonic oscillation time that are applied to compress and deform the hollow fiber material while compressing and deforming the ends of the hollow fiber material are determined by the ultrasonic horn. What is necessary is just to select suitably according to a kind, the kind of hollow fiber thing, desired connection strength, and a softness | flexibility. For example, using an ultrasonic horn with a maximum output of 300 W and an oscillation frequency of 28.5 kHz, hollow braids (polyethylene terephthalate, 830 dtex-96 fil × 16 strokes) having an outer diameter of 2.5 mm and an inner diameter of about 1.2 mm are 2.5 When connecting in parallel by about 30 mm, it is preferable to set the thrust to about 50 to 400 N and the transmission time to about 0.4 to 2 seconds.

As described above, in the manufacturing method according to the present embodiment, the ends of a pair of adjacent hollow filaments are not partially but entirely compressed and deformed so that the ends overlap each other. In addition, it is possible to prevent problems such as insufficient connection strength and an increase in diameter of the connection portion of the hollow fiber article, and to prevent a step from being generated on the side surface of the continuous hollow fiber article. This is because the space portion of the hollow fiber is compressed by the ultrasonic fusion treatment and deformed so as to decrease or disappear.
Therefore, the obtained hollow fiber continuum is in a straight line, and is less likely to be clogged or caught when passing through a portion whose outer diameter is regulated. Therefore, the traveling of the hollow fiber article is stable, and the process stability is prevented from being lowered during the production and processing of the hollow fiber membrane.
In addition, according to the method for producing a continuous hollow fiber article of the above embodiment, the connection time can be shortened, and heating of an ultrasonic horn, a connection jig, etc. is unnecessary, so that fusion to these is prevented. Yes. Further, since ultrasonic fusion is performed, the connection can be made under the same conditions regardless of whether the hollow fiber is in a dry or wet state. Therefore, a continuous hollow fiber product can be efficiently produced.

The continuous hollow fiber article obtained by the above production method can be suitably used as a support for use in producing a hollow fiber membrane.
As a specific method for producing a hollow fiber membrane using a hollow fiber continuum as a support, a hollow fiber continuum is fed from the center hole of an annular nozzle, and the hollow fiber continuum An example is a method in which a film-forming stock solution spun from the outer periphery of an annular nozzle is applied to the outer periphery and solidified to form a continuous hollow fiber membrane, which is then cut.

In addition, this invention is not limited to the said embodiment example, For example, the cross-sectional shape of a hollow fiber article may not be circular, for example, an ellipse, a triangle, a quadrangle | tetragon etc. may be sufficient.
In addition, after compression deformation, the cross-sectional shape of the portion where the ends of the pair of hollow yarns overlap each other is substantially circular, but if the passability of the portion where the outer diameter is restricted is not impaired, The shape (for example, an ellipse, a triangle, a quadrangle, etc.) may be used.

In the present invention, it is possible to use fusion with a heating jig or the like in the fusion process. However, when the object to be heated is in a molten state, the heat treatment is performed to adhere to the heating jig or to maintain the shape of the connection portion. In some cases, a process such as once cooling the tool is required. Preferably, ultrasonic fusion is performed, in which the fusion treatment is performed without heating the fusion jig or the like.
In the case of fusion, the hollow fiber is preferably a hollow braid, a hollow knitted string, or a hollow fiber membrane including these as a constituent member.
Furthermore, in this invention, the edge part of a pair of adjacent hollow fiber thing may be divided | segmented into several, and you may finally fuse | melt the whole. However, in that case, the fusion part may thermally contract while the non-fusion part expands, which may impair running stability of the resulting continuous hollow fiber article. Further, since the subsequent fusion treatment acts on the end portion subjected to the fusion treatment first and overmelts, the desired connection strength may not be obtained. From these things, it is preferable to fuse | melt the whole edge part of a pair of adjacent hollow fiber at once like the said embodiment example.

Hereinafter, the present invention will be described in more detail based on examples.
In connecting the hollow yarns, a connection jig 2 and an ultrasonic welder including the ultrasonic horn 1 as shown in FIGS. 1 and 2 were used.
[Connection jig]
A U-shaped groove 2a having a depth C of 6.1 mm formed linearly was used.
[Ultrasonic welder]
A SONEPET 302S-GM manufactured by Seidensha Electronics Co., Ltd. was used.
The ultrasonic horn 1 has a tip width E of 2.2 mm and a length D of 40 mm, and a groove recessed in an arc along the length direction is formed on the lower surface 1a as a pressing surface, and moves vertically in the vertical direction. We used what to do. Moreover, the ultrasonic horn 1 was installed so that the tip could enter the groove 2 a of the connection jig 2.
A low speed air cylinder was used as the power for the vertical movement of the ultrasonic horn 1. This air cylinder is supplied with air whose pressure is adjusted by a pressure reducing valve and whose exhaust speed is adjusted by a speed controller for low speed.
A stopper was provided so that the tip of the ultrasonic horn 1 stopped immediately before the bottom surface of the groove 2 a of the connection jig 2 to prevent contact between the tip of the ultrasonic horn 1 and the bottom surface of the groove 2 a of the connection jig 2.

(Examples 1-17)
The hollow fiber product (A) 3a and the hollow fiber product (B) 3b having the combinations shown in Tables 1 to 3 were connected to obtain a continuous product of the hollow fiber product.
Specifically, the end 3c of the hollow fiber (A) 3a is inserted into the groove 2a of the connecting jig 2, and then the end 3d of the hollow fiber (B) 3b is shown in Tables 1-3. They were inserted in parallel with the indicated parallel length A. Next, air is supplied to the air cylinder to lower the ultrasonic horn 1 under the conditions shown in Tables 1 to 3, and thrust (surface pressure) is applied to the hollow fiber (A) 3a and the hollow fiber (B) 3b. Multiplied. Then, the entire ends 3c and 3d of the adjacent hollow fiber (A) 3a and hollow fiber (B) 3b are compressed and deformed so that the ends 3c and 3d overlap each other (see FIG. 4). In this state, an ultrasonic wave was oscillated. Thereby, the hollow fiber product (A) 3a and the hollow fiber product (B) 3b were connected by ultrasonic fusion to obtain a continuous hollow fiber product.

The connection strength of the connection part of the obtained hollow fiber article continuum was measured as follows using a digital force gauge (ZP-500N) manufactured by Imada Corporation.
First, a ring capable of hooking the both ends of the hollow fiber continuum was made, one ring was hung on a fixed hook, and the other ring was hung on a digital force gauge hook. Next, turn the digital force gauge in the vertical or horizontal direction, turn on the digital force gauge with no tension applied to the hollow fiber continuum, and reset the displayed value to zero. It was. And it pulled manually and the breaking load was measured using the peak hold function. The breaking load was measured twice, and the average value was obtained. The measurement results are shown in Tables 1-3.

In any of Examples 1 to 17, the breaking load at the connecting portion of the obtained continuous hollow fiber article was sufficiently high. Moreover, the cross-sectional shape of the connecting portion was substantially the same as the cross-sectional shape of the hollow fiber before compression deformation. Therefore, when the hollow fiber continuum obtained in Examples 1 to 10 was passed through the center hole of the annular nozzle, it passed smoothly without being caught at the connecting portion. Moreover, when the hollow fiber continuum obtained in Examples 11 to 17 was passed through the hollow fiber membrane production process, it passed smoothly without being caught at the connecting portion as in Examples 1 to 10. Therefore, a decrease in process stability in the production of hollow fiber membranes was prevented.
Further, by comparing Example 15 and Example 17, it was found that sufficient connection strength was developed regardless of whether the hollow fiber to be connected was dry or wet.

It is a perspective view which shows the connection apparatus used with one Example of the manufacturing method of the hollow fiber continuous article of this invention. It is a figure which shows the state which inserted the hollow fiber article adjacent to the connection jig. It is sectional drawing which shows the aspect which inserted the edge part of a pair of hollow fiber into the groove | channel of the connection jig. It is sectional drawing which shows the aspect which compression-deformed the edge part of a pair of hollow fiber inserted in the groove | channel with the ultrasonic horn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic horn 1a Lower surface 2 Connection jig 2a Groove 3a, 3b Hollow thread 3c, 3d End A Parallel length B Groove width C Groove depth D Ultrasonic horn length E Ultrasonic horn width d ₁ Hollow fiber Article product OD d ₂ hollow yarn was an inner diameter

Claims (3)

A step of arranging a pair of hollow yarn articles such that the ends are adjacent to each other in parallel;
And a step of fusion-bonding the entire ends of a pair of adjacent hollow yarn articles while compressively deforming the ends so that the ends overlap each other. Method.   The method for producing a continuous hollow fiber article according to claim 1, wherein the end portion is in a range of 150 mm or less from one end face toward the center.   A method for producing a continuous hollow fiber article, comprising a step of subjecting end portions of a pair of hollow fiber articles to ultrasonic fusion treatment.

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