JPH0780257A - Production of hollow fiber module - Google Patents

Abstract

PURPOSE:To form a highly reliable terminal sealed part generating no channeling by molding a sealing material into a sheet shape and surrounding the entire periphery of the terminal parts of a predetermined number of hollow fibers by the obtained sheet to integrate the hollow fibers with the sheet and molding the integrated part into the terminal sealed part having a predetermined shape under heating. CONSTITUTION:Three polymer sheets 21, 22, 23 are used and hollow fibers 3 are alternately held between the first and second sheets 21, 22 and between the second and third sheets 22, 23. The respective hollow fibers and the sheets as well as the respective sheets can be integrated by melting the sheets under heating. Since the entire periphery of the end parts of the hollow fibers 3 is preliminarily surrounded by a sheetlike polymer, the channeling caused by the filling insufficiency of a sealing material 2 is not generated in the mutual gaps between the hollow fibers and the reliability of a terminal sealed part can be enhanced. Since the hollow fibers and the sheets are preliminarily integrated, the hollow fibers 3 can be arranged regularly and properly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow fiber module in which a bundle of hollow fiber-like porous separation membranes (hollow fibers) is housed in an outer cylinder, and more specifically, a gas separation membrane,
The present invention relates to a method for producing a hollow fiber module using a hollow fiber used as a dialysis membrane, a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, or the like.

[0002]

2. Description of the Related Art Hollow fibers are separation membranes that utilize the wall of a hollow fiber-like porous material as a selective permeable membrane. This hollow fiber is usually used in order to increase the membrane area per unit volume.
A large number of hollow fibers are bundled and modularized for practical use. The hollow fiber module consists of an element in which a bundle of a large number of hollow fibers is housed in a pressure-resistant outer cylinder such as a cylindrical shape, and has a high packing density of the membrane, such as water, juice,
It can be used in a wide range of fields such as semiconductors, foods, etc. because it can miniaturize the filtration device that separates useful liquid substances such as liquor or solvents from dust and germs, and has excellent pressure resistance. ing. In particular, hollow fibers made of a fluororesin such as tetrafluoroethylene resin (PTFE) are widely used because of their excellent chemical resistance.

The hollow fiber module includes a closed type internal pressure type separation membrane element in which one end of the hollow fiber is heat-sealed and an internal pressure circulation type separation membrane element in which openings at both ends are opened. In these elements, a hollow fiber bundle is housed in an outer cylinder, and at one or both ends thereof, a gap between the hollow fibers and a gap between the hollow fiber bundle and the inner surface of the outer cylinder are sealed with various polymers. It is sealed with.

The advantage of the hollow fiber module is that it can increase the membrane area per unit volume.
It is essential to pack a large number of hollow fibers in the outer cylinder with high density. Therefore, the filling rate of the hollow fibers (the ratio of the total volume of the hollow fibers including the inner cavity to the inner volume of the outer cylinder) is generally required to be 50% or more.

By the way, in recent years, in various industrial fields such as the semiconductor industry, there is an increasing need for ultra-cleaning various chemicals used, for example, co-acids and organic solvents. Therefore, the hollow fiber module is required. A high degree of chemical resistance is also required for the sealing material. However, in general, a heat-meltable polymer having excellent heat resistance and chemical resistance has a high melting point and a high viscosity, so that it is extremely difficult to finely mold the end-sealed portion, and the filling rate of the hollow fiber is increased. It's also difficult.

Conventionally, in a hollow fiber module, as a method for sealing the gap between the hollow fibers and the gap between the hollow fiber bundle and the inner surface of the outer cylinder, a low-viscosity thermosetting resin such as epoxy resin, urethane resin or silicone resin is used. A method is known in which a resin is injected into the end portion of a focusing body, the gap is filled by standing or centrifugal force, and then cured by heating to mold a sealing portion (Japanese Patent Publication No. 44-5526). Japanese Examined Japanese Patent Publication Sho 56-4060
No. 2). However, these thermosetting resins have insufficient heat resistance and chemical resistance.

On the other hand, there has been proposed a method of forming an end-capped portion by impregnating a hollow fiber in a polymer solution (Japanese Patent Publication No. 25603/1989), but in this method, a usable polymer is a chemical resistant material. The solvent is limited to those having insufficient properties, or the solvent that can be used is limited, and a special solvent having problems such as high cost and high risk is required.

Recently, a heat-melting polymer having excellent heat resistance and chemical resistance, such as a fluoropolymer, has been previously molded into a strip-shaped sheet, and the ends of a large number of hollow fibers are formed on the strip-shaped sheet in the longitudinal direction of the strip-shaped sheet. And are placed parallel to each other at a constant interval in a direction orthogonal to, and then wound so that the end of the hollow fiber is on the inner side and wound, and the wound portion of the strip-shaped sheet of the obtained wound body. Has been proposed to form a terminal sealing portion made of a heat-fusible polymer by heating the sheet to melt the sheet (Japanese Patent Application No. 4-259146). However, in this method, although the hollow fiber is in contact with the sheet before and after the hollow fiber, the entire circumference of the hollow fiber is not in contact with the sheet. Therefore, depending on the molding conditions, channels may occur in the gaps between the hollow fibers.

When a channel is formed in the sealing portion, for example,
When the hollow fiber module is used for filtering a liquid, the undiluted solution that has passed through the hollow fiber lumen and the filtered solution that has passed through the wall surface of the hollow fiber are mixed, and normal functions cannot be performed. Therefore, there is a demand for a method of forming a highly reliable sealed portion that does not cause a channel by using a heat-meltable polymer having excellent heat resistance and chemical resistance.

[0010]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a hollow fiber module having a channel-free, highly reliable end-sealing portion formed by using a sealing material made of a polymer such as a fluoropolymer. It is to provide a manufacturing method.
As a result of intensive studies to overcome the above-mentioned problems of the prior art, the inventors of the present invention molded a polymer having excellent heat resistance and chemical resistance, such as a fluoropolymer, into a sheet, and obtained one of the obtained sheets. A single sheet or a plurality of sheets surrounds the entire circumference of the end of each of the hollow fibers, and then, the hollow fibers and the sheet are integrated, and then the integrated product of the hollow fibers and the sheet is end-sealed in a predetermined shape. It has been found that by heat-molding the stopper, the gaps between the hollow fibers are completely filled with the sealing material made of a polymer, and a highly reliable end-sealing portion having no channel can be formed. The present invention has been completed based on these findings.

[0011]

Thus, according to the present invention, the converging body of the hollow fiber-like porous separation membrane is housed in the outer cylinder, and at least one end of the converging body is
In the method for producing a hollow fiber module having a structure in which the gap between the outer cylinder inner surface and the converging body and the gaps between the hollow fibers are end-sealed by a sealant made of a polymer, the sealant is molded into a sheet, The entire circumference of the end of each of the plurality of hollow fibers is surrounded by one or a plurality of the obtained sheets, and then the hollow fibers and the sheet are integrated, and then the hollow fiber and the sheet are integrated. There is provided a method for producing a hollow fiber module, which comprises a step of heat-molding the end-sealing portion having a predetermined shape.

The present invention will be described in detail below. The hollow fiber-like porous separation membrane (hollow fiber) used in the present invention is not particularly limited, but from the viewpoint of chemical resistance, tetrafluoroethylene resin (PTFE), vinylidene fluoride resin (PVdF),
Hollow fibers made of fluororesin such as ethylene-tetrafluoroethylene copolymer (ETFE) are preferred. Among these,
A hollow fiber PTFE porous body having excellent heat resistance and chemical resistance is particularly preferable.

The material of the outer cylinder of the hollow fiber module such as a cylinder is metal such as stainless steel having excellent heat resistance and chemical resistance, or PTFE, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), A fluororesin such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) can be used if necessary. The outer cylinder may be integrally molded with the hollow fiber bundle at the time of forming the terminal sealing portion, or may be housed in the outer cylinder after forming the end sealing portion of a predetermined shape on the hollow fiber bundle. Good.
Furthermore, when the polymer used is solvent-soluble, applying a polymer solution to the ends of the hollow fibers improves the workability when integrating the sheets and the pull-out strength from the end of the hollow fibers after commercialization. Can be expected to improve.

In the present invention, a sealing material (also called a terminal material)
Examples of the polymer used as PFA, F
Fluorine resin such as EP, ETFE, PVdF, trifluorochloroethylene resin (PCTFE), tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer resin (EPE), vinylidene fluoride-propylene hexafluoride Polymer, vinylidene fluoride-propylene hexafluoride-tetrafluoroethylene terpolymer (VdF
System), tetrafluoroethylene-propylene copolymer (TFE
-P type), PFA type, and other fluororubbers or fluorine type thermoplastic elastomers. In the case of fluororubber, a vulcanizing agent, a vulcanization aid, a vulcanization retarder, etc. may be blended and vulcanized during heat molding.

The polymer constituting the sealing material is used by being molded into a sheet shape in advance. Sheet thickness is usually 0.0
It is 5 to 3 mm, preferably 0.1 to 1 mm, and more preferably 0.1 to 0.5 mm. The width of the sheet is equal to or larger than the height of the end sealing portion. When the width of the sheet is large, the sealing portion may be cut to have a predetermined height after heat molding.

The method for manufacturing the hollow fiber module of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an end sealing portion of a hollow fiber module obtained by the manufacturing method of the present invention. A large number of hollow fibers 3 in the outer cylinder 1.
Are filled, and the gap between the inner surface of the outer cylinder and the converging body and the gap between the hollow fibers are terminally sealed with the sealing material 2 made of a polymer.

FIG. 2A is a schematic cross-sectional view showing an example of a method of surrounding the entire circumference of the end portion of each of the plurality of hollow fibers with one or a plurality of polymer sheets. 3 sheets 2
1, 22 and 23, each hollow fiber is used as the first sheet 21
Between the second sheet 22 and the second sheet 22
And the third sheet 23 are alternately sandwiched. The space between the hollow fibers and the sheet and the space between the sheets can be integrated by heating and melting the sheet. In this case, heating may be performed so that the surface of the sheet is partially melted. When the polymer forming the sheet is easily soluble in an organic solvent, the polymer may be dissolved in the organic solvent to integrate the hollow fibers and the sheets and the sheets. Also in this case, it is sufficient that the sheet surface is partially dissolved.

FIG. 2 (b) is a schematic cross-sectional view showing another example of the method of surrounding the entire circumference of the end of each hollow fiber by one or a plurality of polymer sheets. Two sheets 2
Each hollow fiber is sandwiched between 1 and 22, and the entire circumference of the end is surrounded by a sheet. For the integration between the hollow fibers and the sheet and between the sheets, the same method as described above can be adopted.

Further, in FIGS. 2A and 2B,
Instead of each hollow fiber, a support rod having a diameter substantially the same as that of the hollow fiber may be surrounded by a sheet, and then the support rod may be removed to insert the end of each hollow fiber into the hole. As a material for the supporting rod, a heat resistant material such as metal such as stainless steel or ceramics is preferable. Further, the support rod may be not only a solid body but also a hollow body (pipe). The diameter of the support rod should be the same as or slightly larger than the diameter of the hollow fiber used. According to this method, it is possible to easily surround the entire circumference of the end portion of the hollow fiber even in the case of a relatively hardened sheet. Further, if the support rods are inserted and the respective sheets are heated and melted or dissolved with a solvent so as to be integrated, the subsequent operation is easy.

When the hollow fibers and the sheet are integrated with each other, the workability of the integration is improved by coating the end of each hollow fiber with a solution of a heat-meltable polymer soluble in a solvent.
Moreover, the hollow fibers are less likely to come off from the sealing portion after the heat molding, which is preferable. In this way, the integrated product in which the plurality of hollow fibers and the sheet are integrated together is then rolled into a cylindrical shape. This is set in a heating device, and the sheet is molded into a predetermined shape while being heated and melted. In Figure 3,
An example of the hollow fiber bundle in which the terminal sealing part was formed is shown. In this way, the hollow fiber bundle having the end-sealed portion formed by heat molding is housed in the cylinder. The width of the seat is long,
Therefore, when the terminal sealing portion protrudes from the cylinder, or when it is necessary to open the hollow fiber, the end portion is cut as shown in FIG.

According to the manufacturing method of the present invention, since the entire circumference of the end of each hollow fiber is surrounded by the sheet-shaped polymer in advance, a channel may be formed in the gap between the hollow fibers due to insufficient filling of the sealing material. Therefore, the reliability of the end sealing portion can be dramatically improved. In addition, since each hollow fiber and the sheet are integrated in advance, it is easy to mold the sealing part with a predetermined shape, and it is easy for the hollow fibers to be regularly and parallelly arranged. It is possible to manufacture hollow fiber modules arranged in

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Example 1] Outer diameter 2.8 mm, inner diameter 2.0
mm flame-treated PTFE porous hollow fiber 1100 mm
630 pieces cut into long pieces were prepared. (1) VdF-based fluororubber [manufactured by Daikin Industries, Ltd., trade name DAIEL G-1001] mixed with a vulcanizing agent and a vulcanization aid is molded into a sheet having a thickness of 0.3 mm by a calender roll machine. Then, three pieces cut into a width of 50 mm were prepared. (2) Each hollow fiber was alternately sandwiched between the first and second sheets and between the second and third sheets of the above three strip-shaped sheets, and in this state, the temperature was raised to 95 ° C. It was melted and integrated on a hot plate. The hollow fibers and the sheets and the sheets were melt-integrated. (3) The other end of each hollow fiber was treated in the same manner to integrate each hollow fiber with the sheet.

(4) Next, the integrated product was wound in the longitudinal direction of the sheet to form a bundle. (5) One end of the bundle was set in a heating device, heated to 110 ° C., molded into a diameter of 88 mm, and then vulcanized at 160 ° C. (6) Next, the other end was similarly heat-molded. (7) The obtained molded product was inserted into the outer cylinder. (8) Both ends were cut to open the hollow fiber. You may insert in an outer cylinder, after cutting both ends and opening a hollow fiber. The resulting hollow fiber module was tightly sealed with a sealing material made of a heat-fusible polymer in the gap between the inner surface of the outer cylinder and the converging body and the gaps between the hollow fibers. Were lined up vertically.

[Example 2] VdF type rubber [Dayer G-
704] was mixed with an acid acceptor and the like, and the integration was carried out by dissolution with methyl ethyl ketone instead of heat, thereby preparing a hollow fiber module having the same shape as in Example 1. . The resulting hollow fiber module was tightly sealed with a sealing material made of a heat-fusible polymer in the gap between the inner surface of the outer cylinder and the converging body and the gaps between the hollow fibers. Were lined up vertically.

[0026]

According to the manufacturing method of the present invention, a polymer having excellent heat resistance and chemical resistance can be used as a sealing material to manufacture a hollow fiber module in which hollow fibers are densely packed. . INDUSTRIAL APPLICABILITY The hollow fiber module of the present invention has a high reliability of the terminal sealing portion, and is particularly suitable in fields such as the semiconductor industry where chemical resistance is required.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a terminal sealing portion of a hollow fiber module obtained by the manufacturing method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a method of integrating each hollow fiber and a polymer sheet. (A) is an example using three sheets, and (b) is an example using two sheets.

FIG. 3 is an external view of a hollow fiber bundle obtained by the production method of the present invention and having end caps formed thereon.

FIG. 4 is an external view showing a step of cutting and opening an end of a hollow fiber bundle housed in an outer cylinder.

[Explanation of symbols]

 1 Outer Cylinder 2 Sealing Material 3 Hollow Fiber 4 End Sealing Section 5 Cutting Site 22 Polymer (Sealing Material) Sheet 23 Polymer (Sealing Material) Sheet 24 Polymer (Sealing Material) Sheet

Claims (3)

[Claims] 1. A hollow fiber-shaped porous separation membrane (hereinafter,
A bundle of hollow fibers is abbreviated), and at least at one end of the bundle, the gap between the inner surface of the outer cylinder and the bundle and the gap between the hollow fibers are terminated by a sealing material made of a polymer. In a method for producing a hollow fiber module having a sealed structure, a sealing material is molded into a sheet, and one or a plurality of the obtained sheets surrounds the entire circumference of the end of each hollow fiber. Then, the step of integrating each hollow fiber and the sheet, and then heat-molding the integrated product of each hollow fiber and the sheet into the end-sealing portion having a predetermined shape, the production of the hollow fiber module. Method. 2. In the step of surrounding the entire circumference of the end portion of each of the plurality of hollow fibers with one or a plurality of sheets, instead of each hollow fiber, the entire circumference of a supporting rod having substantially the same diameter as the hollow fiber is previously prepared. The method according to claim 1, wherein said hollow fiber is surrounded by a sheet, then the support rod is removed, and the end of each hollow fiber is inserted into the hole. 3. The production method according to claim 1, wherein in the step of integrating the hollow fibers and the sheet, the sheet is integrated by heating and melting the sheet or dissolving the sheet with a solvent.