JP5657852B2 - Hollow fiber membrane module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a hollow fiber membrane module used in fields such as the electronics industry, food industry, and beverage industry, and more particularly to a separation / deaeration hollow fiber membrane module having solvent resistance.

  Separation membrane modules such as reverse osmosis membranes, ultrafiltration membranes, microfiltration membranes, gas separation membranes, and dialysis membranes are used in processes such as pervaporation, solvent filtration, solvent treatment, and chemical degassing. . In such applications, solvent resistance is required not only for the separation membrane itself but also for other members constituting the module.

  For example, when a hollow fiber membrane module having a potting part (sealing part) made of a thermosetting resin is used for the above-mentioned applications, the thermosetting resin swells and elutes depending on the type of solvent or chemical solution, and cracks are generated. As a result, problems such as a decrease in adhesiveness, occurrence of leakage, and a decrease in the purity of the processed product may occur. Therefore, Patent Document 1 and Patent Document 2 propose a method of forming a potting portion by molding a thermoplastic resin such as polyethylene resin instead of a thermosetting resin, thereby improving the solvent resistance.

  For example, Patent Document 1 discloses a method of welding a hollow fiber membrane in two stages using a polyethylene wax for the first time and a mixture of polyethylene wax and low molecular weight polyethylene for the second time. However, the potting portion formed in this way is easily damaged at a portion having a small molecular weight, and when the module is subjected to chemical or physical invasion, the potting portion itself or the hollow fiber membrane is easily cracked.

In the Example of patent document 2, the potting part is formed using polyethylene with respect to the polypropylene hollow fiber membrane. However, since the adhesion between polyethylene and polypropylene is low, defects may occur at the adhesive interface due to switching of organic solvents accompanying line cleaning, etc., or distortion due to thermal shrinkage differences during processing remains, and the module is chemically or When subjected to physical invasion, the potting part itself or the hollow fiber membrane tends to crack.
JP 7-171356 A Japanese Patent No. 3174267

  The present invention has been made to solve the above-described problems of the prior art. That is, the object of the present invention is that the potting part, the module case and the hollow fiber membrane are bonded and fixed in a highly liquid-tight or air-tight manner without impairing the properties of the hollow fiber membrane, and the moldability, mechanical strength, solvent resistance An object of the present invention is to provide a hollow fiber membrane module excellent in characteristics such as low elution and a method for producing the same.

The present invention is a hollow fiber membrane module in which a hollow fiber membrane is fixed and sealed using polyethylene or polypropylene ,
The material used for the sealing part of the module is polyethylene polymerized using a metallocene catalyst having a number average molecular weight (Mn) of 2000 or more and a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 3 or less. polypropylene Tona is,
The hollow fiber membrane is made of polyethylene or polypropylene,
The case material of the part in contact with the sealing part of the module is made of polyethylene or polypropylene polymerized using a metallocene catalyst having a weight average molecular weight to number average molecular weight ratio (Mw / Mn) of 2.0 to 5.0. A hollow fiber membrane module characterized by the above.

Furthermore, the present invention provides the above hollow fiber membrane module in which the hollow fiber membrane is fixed and sealed with polyethylene or polypropylene , and the case material of the portion in contact with the sealing portion of the module has a number average molecular weight (Mn) of 2000. The above-described hollow fiber membrane module made of polyethylene or polypropylene having a weight average molecular weight to number average molecular weight ratio (Mw / Mn) of 3 or less.

The present invention further provides a method for producing Soraitomaku module in the above, the molding temperature of the sealing portion, is in the production method of the hollow fiber membrane module and satisfies the following relationship .

  Softening point of hollow fiber membrane> Molding temperature ≧ Softening point of case member> Melting point of material used for sealing part

  In the present invention, since a specific resin is used for the material for the sealing part of the hollow fiber membrane module and the case material, the potting part, the module case, and the hollow fiber membrane are highly liquid without impairing the characteristics of the hollow fiber membrane. It is possible to provide a hollow fiber membrane module which is tightly or airtightly bonded and fixed and excellent in various characteristics, and a method for producing the same.

  In the present invention, the hollow fiber membrane only needs to satisfy desired solvent resistance and chemical resistance, and various conventionally known hollow fiber membranes can be used. From the viewpoints of flexibility, strength, chemical resistance, low cost, etc. of the hollow fiber membrane, a hollow fiber membrane made of a tetrafluoroethylene resin or a polyolefin resin is particularly preferable. Among these, a hollow fiber membrane made of polyolefin resin such as polyethylene, polypropylene, poly (4-methyl-1-pentene) is preferable. Furthermore, from the viewpoint of adhesiveness and compatibility with a potting portion (sealing portion) made of a polyolefin resin, a hollow fiber membrane made of a polyolefin resin mainly composed of polyethylene or polypropylene is preferable.

  The hollow fiber membrane may be a porous membrane used for normal filtration or a non-porous homogeneous membrane used for gas separation or the like. The film structure may be a film having a uniform internal structure, or a composite film having both a porous layer and a homogeneous layer.

  The thickness of the hollow fiber membrane is not particularly limited. Usually, the outer diameter is preferably about 100 to 2000 μm. When the outer diameter is 100 μm or more, the gap between the hollow fiber membranes is relatively wide and the potting material can easily enter. If it is 2000 μm or less, the overall size of the module having a large number of hollow fiber membranes will be reduced, and the volume of the potting part will be reduced accordingly. Can be suppressed.

  The hollow fiber membrane module of the present invention is formed by potting a hollow fiber membrane by fixing and sealing with a polyolefin resin. For example, a bundle of hollow fiber membranes (hollow fiber membrane bundle) is disposed in a module case, and at least one end of the hollow fiber membrane bundle is in an open state. A space in which the hollow fiber membrane focusing body is disposed is sealed in the case while the vicinity of the opening end of the focusing body is fixed by the polyolefin resin. The “sealing portion” of the hollow fiber membrane module is a portion that fixes the vicinity of the end portion of the hollow fiber membrane and performs sealing for potting as described above. In the present invention, as necessary, the sealing portion is referred to as a “potting portion”, and the material used for the sealing portion is referred to as a “potting material”. Moreover, the case material of the part which contacts the sealing part of a hollow fiber membrane module is a material which comprises the part which contact | connects a sealing part among the module cases which are the main body containers of a module.

  In the present invention, the potting material is made of a polyolefin resin having a number average molecular weight (Mn) of 2000 or more and a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 3 or less. If the Mn of the polyolefin resin is 2000 or more, the mechanical strength and toughness of the potting part are improved, and durability and impact resistance that can withstand long-term use are imparted. About the upper limit of Mn, 150,000 or less is preferable. Furthermore, if Mw / Mn of the polyolefin resin is 3 or less, the strength is improved while maintaining the moldability, and mechanical defects (craze) are reduced. Moreover, since this polyolefin resin has few low molecular weight components, the molding temperature of the module part can be lowered and elution can be reduced. As a result, the properties such as moldability, mechanical strength, solvent resistance and low elution properties required for the potting material are satisfactorily satisfied without impairing the properties of the hollow fiber membrane.

The density of the polyolefin resin used as the potting material is preferably from 0.85 to 0.90 g / cm ³ . This density is a value measured under the conditions employed in the examples described later.

  Specific examples of the polyolefin resin used as the potting material include polyethylene, ethylene-α-olefin copolymer, and polypropylene. The ethylene-α-olefin copolymer is preferably at least one copolymer of ethylene and an α-olefin having 4 to 8 carbon atoms.

  Examples of commercially available polyethylene trade names include, for example, Creolex (Asahi Kasei Chemicals Corporation), Harmolex Kernel (Nippon Polyethylene Co., Ltd.), Affinity (Dow Chemical Co., Ltd.) Is mentioned. As a trade name of polypropylene, for example, Wintech (manufactured by Nippon Polypro Co., Ltd.), Ceridust (manufactured by Clariant Co., Ltd.) can be mentioned.

  When polyethylene is used as the potting material, the melting point (Tm) is preferably 55 to 120 ° C. In the case of using an ethylene copolymer, the melting point (Tm) is preferably 30 to 115 ° C. When polypropylene is used, the melting point (Tm) is preferably 80 to 140 ° C. These Tm are values measured with a differential scanning calorimeter (DSC).

Polyolefin resin used as the potting material, Ru polymer der obtained using a metallocene catalyst. When using a metallocene catalyst, the molecular weight distribution is basically narrow compared to the case of using other catalysts (such as Ziegler-Natta catalyst), although it is the same type of polyolefin resin, low molecular weight components and A polyolefin resin having a low crystalline component and a low melting point can be obtained. In addition, since the polyolefin resin obtained using the metallocene catalyst has a narrow molecular weight distribution, in the case of a polymer using another catalyst, it exhibits adhesiveness even in a combination such as polyethylene / polypropylene that does not adhere. It is also preferable from the viewpoint of expanding the selection range of the resin.

  If necessary, additives such as antioxidants, ultraviolet absorbers, lubricants and antiblocking agents can be added to the potting material as long as the object of the present invention is not impaired.

  In the present invention, the portion of the case material in contact with the sealing portion of the module is made of a polyolefin resin having a number average molecular weight (Mn) of 2000 or more and a weight average molecular weight to number average molecular weight ratio (Mw / Mn) of 3 or less. . If Mn is 2000 or more, the mechanical strength and toughness of the case portion in contact with the sealing portion will be improved, and durability and impact resistance that can withstand long-term use will be imparted. The upper limit of Mn is preferably 150,000 or less from the viewpoint of moldability and the like. If Mw / Mn is 3 or less, the strength is improved while maintaining the moldability, and mechanical defects (craze) are reduced. Moreover, since the polyolefin resin has few low molecular weight components, elution is reduced, and the melting point can be lowered while maintaining the strength, so that the adhesiveness and compatibility are improved. From such a viewpoint, it is preferable to use the polyolefin resin obtained by using the metallocene catalyst described above also in the case material. As the case material, it is preferable to use a high molecular weight polyolefin resin having a low melt flow rate (MFR). Specifically, the MFR of the polyolefin resin used as the case material is preferably 0.1 to 10 g / 10 min. This MFR is a value measured under the conditions adopted in the examples described later.

  Specific examples of the polyolefin resin used as the case material include polyethylene and polypropylene. The melting point (Tm) of polyethylene is preferably 120 ° C. or lower, and the melting point (Tm) of polypropylene is preferably 140 ° C. or lower. Examples of commercially available polyethylene trade names include Creolex (manufactured by Asahi Kasei Chemicals Corporation) and affinity (Dow Chemical Co., Ltd.). Moreover, as a trade name of polypropylene, for example, Wintech (manufactured by Nippon Polypro Co., Ltd.) and the like can be mentioned.

  A hollow fiber membrane module can be manufactured by the following methods, for example.

  For example, a plurality of hollow fiber membranes are scraped to form a converging body, and at least one end of the hollow fiber membrane converging body is aligned, and the end of the converging body is appropriately attached to the hollow fiber membrane by an adhesive or heat fusion. When there is an opening, temporarily fix it including the blockage. Next, the hollow fiber membrane focusing body is disposed in the module case so that the end of the focusing body is substantially located at the end of the module case. Next, a polyolefin resin is supplied to a portion where a potting portion of at least one end portion of the hollow fiber membrane bundle disposed in the module case is to be formed. This polyolefin resin is heated and melted, and then cooled and solidified. Thereby, a potting part is shape | molded and the edge part of a hollow fiber membrane focusing body is fixed in a module case. Thereafter, the potting part is cut at the end face of the module case to form the open end face of the hollow fiber membrane.

  Moreover, about a hollow fiber membrane focusing body, the thing of another structure can also be used. For example, one or a plurality of hollow fiber membranes are folded back at a predetermined length, and the ends of adjacent folded hollow fiber membranes forming a looped shape are constrained by yarns to form a sheet-like hollow fiber Membrane knitted fabric. Then, the spiral bundles are wound in parallel with the arrangement direction of the hollow fiber membranes, that is, the sheet-like hollow fiber membrane knitted fabric is wound in a spiral form in parallel with the arrangement direction of the hollow fiber membranes, To do. When such a sheet-like hollow fiber membrane knitted fabric is used, the hollow fiber membranes can be arranged uniformly in the module case, and further, for the purpose of aligning the ends of the focusing body and closing the opening. The temporary fixing step thus made becomes unnecessary.

  Next, a method for forming the potting portion will be described in detail.

  A potting part is formed in the at least one edge part of the hollow fiber membrane focusing body arrange | positioned in a module case, for example. First, a potting material is supplied to a portion (potting forming portion) where the potting portion is to be formed, heated and melted, and then cooled and solidified to form a potting portion. By molding the potting portion, the ends of the hollow fiber membranes are fixed to each other and the hollow fiber membrane focusing body is fixed to the module case.

  The operation of supplying the potting material to the potting forming portion may be performed simultaneously with the formation of the plurality of hollow fiber membranes or after the formation of the converging body. In particular, it is preferable to uniformly fill the space between the outer surface of at least one end of the hollow fiber membrane bundle and the hollow fiber membrane in the potting molding processing part. The filling rate of the hollow fiber membrane with respect to the volume of the module case is preferably 20% or more and 60% or less.

  The potting material is preferably used as a powder from the viewpoint of dispersibility during molding. The shape of the powder is not particularly limited, and may be any shape such as a spherical shape, a rectangular shape, a needle shape, or an elliptical shape. The particle diameter of the powder is preferably larger than the hole diameter of the hollow fiber membrane, which makes it difficult for the powder to enter the hollow interior of the hollow fiber membrane during molding. Furthermore, in order to improve the dispersibility of the powder, it is preferable to prepare a dispersion composed of a polyolefin resin powder and a volatile organic solvent or water, and supply the dispersion to the potting molding processing section. The dispersion liquid can be supplied to the potting molding processing section by, for example, applying or filling the potting molding processing section, or immersing the end of the hollow fiber membrane focusing body in the dispersion liquid.

  The method for producing the polyolefin resin powder is not particularly limited as long as the powder having a desired particle size distribution can be obtained. Specific examples include (1) mechanical pulverization method (room temperature / freeze pulverization, wet pulverization, jet pulverization, etc.), (2) chemical pulverization / spraying method, (3) forced emulsification method (melt emulsification, solution emulsification, etc.), (4) Examples include suspension polymerization. Of these, (1) mechanical pulverization method and (2) chemical pulverization / spraying method are preferable from the viewpoint of the problem of residues.

  After filling the potting molding processing part with polyolefin resin powder, a solution can be used for dispersion of the powder. This method is also preferable from the viewpoint of reducing residues.

  In a state where the potting material powder is uniformly supplied to the potting molding processing section, for example, heating may be performed while rotating the module case, that is, while applying centrifugal force for thickening.

  In the present invention, the molding temperature of the potting part is preferably lower than the softening point of the resin material constituting the hollow fiber membrane (hereinafter referred to as “the softening point of the hollow fiber membrane”). If the molding temperature is lower than the softening point, the thermal shrinkage of the hollow fiber membrane is small, and the porous structure of the hollow fiber membrane is maintained, so that the potting material is impregnated into the porous structure and the anchor effect is exhibited. As a result, the adhesion between the hollow fiber membrane and the potting part is improved. From this point of view, the melting point (Tm) of the polyolefin resin used as the potting material is preferably 10 ° C. or more lower than the melting point of the resin material constituting the hollow fiber membrane, more preferably 20 ° C. or more. preferable.

  Further, the molding temperature of the potting part is preferably near or above the softening point of the resin material constituting the case member (hereinafter referred to as “softening point of the case member”). The range of “point” to “the softening point of the case member + about 20 ° C.” is preferable. This enables welding to the case member, lowers the viscosity of the potting material (polyolefin resin) during molding, and improves the impregnation of the potting material between the hollow fiber membranes. Moreover, the melting point of the potting material is usually lower than the melting point of the case member.

  Summarizing the above points, it is preferable that the molding temperature of the potting portion satisfies the following relational expression.

  Softening point of hollow fiber membrane> Molding temperature ≧ Softening point of case member> Melting point of potting material

  Further, the heating at the time of molding the potting part can be performed in stages. For example, preheating is first performed below the softening point of the case member and above the melting point of the potting material, and the porous structure of the hollow fiber membrane is sufficiently impregnated with the potting material, and then the hollow fiber is continuously or batch processed. Molding can be performed at a molding temperature lower than the softening point of the film and higher than the softening point of the case member. Such a stepwise heating method is preferable from the viewpoint of preventing defects in the potting portion.

  The potting part is molded at the molding temperature as described above, and then the end face of the hollow fiber membrane in the vicinity of the potting part is cut to form the open end face. In this way, the hollow fiber membrane module of the present invention is obtained.

  Hereinafter, the present invention will be described in more detail based on examples. Each physical property was measured by the following method.

[Melting point (Tm)]
A differential scanning calorimeter (DSC) manufactured by Seiko Denshi Kogyo was used for the measurement of the melting point (Tm). Specifically, about 5 mg of sample was melted at 200 ° C. for 5 minutes, crystallized by cooling to 40 ° C. at a rate of 10 ° C./min, and then further heated to 200 ° C. at 10 ° C./min to melt. The melting point was determined from the melting peak temperature at the time and the melting end temperature.

[Vicat softening point]
The Vicat softening point is a temperature measured by ASTM D 1525-70 or JISK7206. When a gauge with a 1 kg load is placed on the plastic surface and overheated, the needle tip of the gauge enters 1 mm into the plastic. It is expressed by the temperature at the time.

[Ratio of weight average molecular weight to number average molecular weight (Mw / Mn)]
It measured by the following conditions by gel permeation chromatography (GPC).
GPC measuring device: WATERS 150-GPC (manufactured by WATERS)
Temperature: 140 ° C
Solvent: 1,2,4-trichlorobenzene concentration: 0.05% (injection amount: 500 microliters)
Column: One Shodex GPC AT-807 / S, two Tosoh TSK-GEL GMH6-HT Dissolution conditions: 160 ° C., 2.5 hours Calibration curve: A polystyrene standard sample was measured, and a polyethylene conversion constant (0.48) ) And calculated in the third order.

[Melt flow rate (MFR)]
In accordance with JIS K7210, polyethylene is melt flow rate (MFR 2.16) (g) by measuring the mass of resin extruded in a strand form for 10 minutes at a load of 2.16 Kg at 190 ° C. using a melt indexer. / 10 min). In the case of polypropylene, the melt flow rate (MFR 2.16) (g / 10 min) was determined by measuring the mass of the resin extruded in a strand shape for 10 minutes at 210 ° C.

[density]
In accordance with JIS K7112, a sample obtained by heat-treating a strand obtained at the time of MFR measurement at 190 ° C. under a 2.16 Kg load at 100 ° C. for 1 hour and gradually cooling to room temperature over 1 hour was measured using a density gradient tube. .

<Example 1>
A Ziegler-Natta catalyst high-density polyethylene (trade name Suntech B161, manufactured by Asahi Kasei Chemicals Corporation, softening point: 130 ° C., melting point: 140 ° C., Mw / Mn = 10.3) having an MFR of 1.1 g / 10 min is used as a raw material. A hollow fiber membrane having an outer diameter of 380 μm, an inner diameter of 270 μm, and a pore diameter of 0.1 μm was manufactured.

Two thousand hollow fiber membranes were bound to form a converging body and inserted into a module case. As the module case, a metallocene catalyst-based high-density polyethylene having an MFR of 1.1 g / 10 min (trade name Affinity PL1840G, manufactured by Dow Chemical Co., Ltd., density 0.9090 g / cm ³ , Vicat softening point 95 ° C., melting point 106 ° C., Mn 110000, Mw / Mn = 2.0).

The potting material is a metallocene catalyst low density polyethylene (trade name Affinity GA1950, manufactured by Dow Chemical Co., Ltd., density 0.870 g / cm ³ , melting point 70 ° C., Mn 22000, Mw, MFR 500 g / 10 min · 190 ° C. /Mn=2.10) was used and a powder having an average particle diameter of 100 μm obtained by freeze pulverization was used.

  And the said powder was supplied between the films | membranes of the one end part of a hollow fiber membrane focusing body, and it heat-melted and solidified at 110 degreeC, having centrifuged. Next, the hollow fiber membrane module was obtained by cutting and opening the end of the hollow fiber membrane.

  This hollow fiber membrane module is immersed in MEK (methyl ethyl ketone) at room temperature for 3 days, further immersed in NMP (n-methylpyrrolidone) for 3 days, washed with ethyl alcohol, dried at 40 ° C. for 48 hours, and again in ethyl alcohol. To make it hydrophilic. Then, when the hole diameter was measured by the bubble point method, a normal bubble point value of 200 kPa was obtained. In addition, no leak was observed in any of the adhesion portion between the module case and the potting portion and the adhesion portion between the film and the potting portion. Further, no distortion of the module outer cylinder portion was observed.

<Example 2>
As a raw material, Ziegler-Natta catalyst polypropylene (trade name FY6H, manufactured by Nippon Polypro Co., Ltd., Mw / Mn = 5.0, softening point 160 ° C., melting point 170 ° C.) having an MFR of 1.9 g / 10 min, A hollow fiber membrane having a diameter of 266 μm and an inner diameter of 208 μm was produced.

  590 hollow fiber membranes were bound to form a converging body and inserted into a module case. As a module case, a metallocene catalyst polypropylene having a MFR of 7.0 g / 10 min (trade name Wintech WFX4T, manufactured by Nippon Polypro Co., Ltd., Vicat softening point, 115 ° C., melting point 125 ° C., Mn 85000, Mw / Mn = 2. The case consisting of 8) was used.

  For the potting material, an average particle diameter obtained by freeze-pulverizing polypropylene wax (trade name Ricocene PP1502, Clariant Co., Ltd., melting point 100 ° C., Mn2900, Mw / Mn = 2.31) produced with a metallocene catalyst. A 100 μm powder was used.

  And the said powder was supplied between the films | membranes of one edge part of a hollow fiber membrane focusing body, and it heat-melted at 130 degreeC and solidified. Next, the hollow fiber membrane module was obtained by cutting and opening the end of the hollow fiber membrane.

  About this hollow fiber membrane module, the process from the immersion to MEK to the hydrophilization in ethyl alcohol was implemented like Example 1. FIG. Thereafter, when the pore diameter was measured by the bubble point method, a bubble point value of 500 kPa equivalent to that of the hollow fiber membrane was obtained. In addition, no leak was observed in any of the adhesion portion between the module case and the potting portion and the adhesion portion between the film and the potting portion. Further, no distortion of the module outer cylinder portion was observed.

<Example 3>
In the same manner as in Example 1, a hollow fiber membrane bundle was inserted into the module case.

For the potting material, polypropylene wax (trade name Ricocene PP1502, manufactured by Clariant Co., Ltd., density 0.870 g / cm ³ , melting point 100 ° C., Mn 6700, Mw / Mn = 2.3) was frozen as a material for potting. A powder having an average particle diameter of 100 μm obtained by pulverization was used.

  And the said powder was supplied between the films | membranes of one edge part of a hollow fiber membrane focusing body, and it heat-melted at 125 degreeC and solidified. Next, the hollow fiber membrane module was obtained by cutting and opening the end of the hollow fiber membrane.

  About this hollow fiber membrane module, the process from the immersion to MEK to the hydrophilization in ethyl alcohol was implemented like Example 1. FIG. Thereafter, when the pore diameter was measured by the bubble point method, a bubble point value of 500 kPa equivalent to that of the hollow fiber membrane was obtained. In addition, no leak was observed in any of the adhesion portion between the module case and the potting portion and the adhesion portion between the film and the potting portion. Further, no distortion of the module outer cylinder portion was observed.

<Example 4>
The same hollow fiber membrane bundle as that used in Example 2 was used, and the same module case and potting material as those used in Example 1 were used.

  And after supplying the said powder between the films | membranes of one edge part of a hollow fiber membrane focusing body, the hollow fiber membrane focusing body was inserted in the module case. First, it was melted by heating at 90 ° C. for 1 hour, and a potting member was impregnated into the porous structure of the hollow fiber membrane. Subsequently, the temperature was raised to 125 ° C. so that the case portion and the potting portion were heat-sealed, and then gradually cooled and solidified. Subsequently, the edge part was cut and the film | membrane end part was opened, and the hollow fiber membrane module was obtained.

  About this hollow fiber membrane module, the process from the immersion to MEK to the hydrophilization in ethyl alcohol was implemented like Example 1. FIG. Then, when the hole diameter was measured by the bubble point method, a normal bubble point value of 200 kPa was obtained. In addition, no leak was observed in any of the adhesion portion between the module case and the potting portion and the adhesion portion between the film and the potting portion. Further, no distortion of the module outer cylinder portion was observed.

<Example 5>
Polypropylene produced using a Ziegler-Natta catalyst for the inner layer and outer layer (support layer) using a three-layer nozzle (trade name FY6H, manufactured by Nippon Polypro Co., Ltd., MFR 1.1 g / 10 min, density 0 .87 g / cm ³ , melting point 160 ° C., softening point 150 ° C., Mw / Mn = 5.0), and an intermediate layer portion (homogeneous layer) with a polypropylene soft material (trade name: Zelas 7023, Mitsubishi Chemical Corporation) The unstretched hollow fiber was spun in the same manner as in Example 1 except that MFR 2.0 g / 10 min, density 0.89 g / cm ³ , melting point 140 ° C., Mw / Mn = 4.5) was used. Obtained. The inner diameter of the unstretched hollow fiber was 230 μm, and the three layers were arranged concentrically.

  The obtained undrawn yarn was drawn 1.25 times at 23 ± 2 ° C., and subsequently drawn by 3.4 times in a heating furnace at 130 ° C., and then in a heating furnace at 100 ° C. Was provided with a relaxation step of 0.4 times, and finally molded so that the total draw ratio was 3 times to obtain a composite hollow fiber membrane. This multilayer composite hollow fiber membrane had a three-layer structure in which a homogeneous membrane (non-porous thin film) was sandwiched between two porous layers.

When the air permeation rate of this composite hollow fiber membrane was measured, the oxygen permeation rate (Q _O2 ) at room temperature (23 ± 2 ° C.) was 0.12 m / hr · Mpa, and the nitrogen permeation rate (Q _N2 ) was 0.03 m / hr · Mpa, and the separation factor (Q _O2 / Q _N2 ) was 4.0. In addition, the separation factor of the polymer used in the homogeneous layer was maintained at 4.0. Further, no leakage occurred even when the BCA liquid was pressurized and fed at 0.5 MPa.

This hollow fiber membrane was bound in the same manner as in Example 1 to form a converging body and inserted into the module case. As a module case, polypropylene produced by a metallocene catalyst (trade name Wintech WFX4T, manufactured by Nippon Polypro Co., Ltd., MFR 7.0 g / 10 min · 230 ° C., density 0.90 g / cm ³ , melting point 125 ° C., Mw / A case consisting of Mn = 2.8) was used.

  As the potting resin, powder having an average particle size of 100 μm obtained by freeze-pulverizing the same polypropylene wax (trade name Ricosen PP1502) as in Example 2 was used.

  Then, the heating and melting temperature while centrifuging was changed to 125 ° C., and a hollow fiber membrane module was produced in the same manner as in Example 1.

  About this hollow fiber membrane module, MEK solution was pressure-fed at 0.4 MPa and allowed to stand for 6 days, but no leakage of chemical solution was found on the vacuum side (outside the degassing membrane).

<Example 6>
The 2000 hollow fiber membranes used in Example 5 were bundled into a converging body and inserted into the module case. As the module case, a metallocene catalyst-based high-density polyethylene having a MFR of 1.1 g / 10 min (trade name Cleorex K4125, manufactured by Asahi Kasei Chemicals Corporation, Vicat softening point 121 ° C., melting point 130 ° C., Mn 16000, Mw / Mn = 5 0.0) was used.

The potting material is a metallocene catalyst low density polyethylene (trade name Affinity GA1950, manufactured by Dow Chemical Co., Ltd., density 0.870 g / cm ³ , melting point 70 ° C., Mn 22000, Mw, MFR 500 g / 10 min · 190 ° C. /Mn=2.10) was used and a powder having an average particle diameter of 100 μm obtained by freeze pulverization was used.

  And the said powder was supplied between the films | membranes of one edge part of a hollow fiber membrane convergence body, and it heat-melted and solidified at 120 degreeC, carrying out centrifugation. Next, the hollow fiber membrane module was obtained by cutting and opening the end of the hollow fiber membrane.

  Regarding this hollow fiber membrane module, MEK solution was pressurized and delivered to the inside of the membrane module at 0.4 Mpa and left for 6 days. However, leakage of the chemical solution was observed on the vacuum side (outside the degassing membrane). There wasn't.

<Comparative Example 1>
The same hollow fiber membrane bundle as that used in Example 2 was used.

  As a module case, a low density polyethylene (trade name FLEXMORE DFDB-1085NT, manufactured by Dow Chemical Co., Ltd., MFR 1.0 g / 10 min, softening point 108 ° C., melting point 118 ° C., Mn 32000, Mw / Mn = 7) was used.

Potting materials include Ziegler-Natta low density polyethylene (trade name Sumikasen G807, manufactured by Sumitomo Chemical Co., Ltd., MFR 75 g / 10 min, density 0.919 g / cm ³ , melting point 107 ° C., Mn 8600, Mw / Mn = 11.3. ) Was used to obtain a powder having an average particle diameter of 100 μm obtained by freeze-pulverizing.

  And the said powder was supplied between the films | membranes of one edge part of a hollow fiber membrane focusing body, and it heat-melted at 115 degreeC and solidified. Next, the hollow fiber membrane module was obtained by cutting and opening the end of the hollow fiber membrane.

  There was no leakage at the adhesive part between the case part and the potting part of this module, but the case member was distorted. Between the membrane and the potting member, there was a portion where the potting resin was not impregnated in the porous structure.

  About this hollow fiber membrane module, the process from the immersion to MEK to the hydrophilization in ethyl alcohol was implemented like Example 1. FIG. Thereafter, an attempt was made to measure the pore diameter by the bubble point method, but because the defect occurred between the membrane and the potting resin, the pore size of the membrane could not be measured.

<Comparative example 2>
Ziegler-Natta low-density polyethylene (trade name Sumikasen G807, manufactured by Sumitomo Chemical Co., Ltd., MFR 75 g / 10 min · 190 ° C., density 0.919 g / cm ³ , melting point 107 ° C., Mn 8600, Mw / Mn = 11.3) A hollow fiber membrane module was produced in the same manner as in Example 6 except that a powder having an average particle diameter of 100 μm obtained by freeze-pulverizing was used.

  About this hollow fiber membrane module, when MEK solution is pressurized and fed to the inside of the membrane module at 0.4 Mpa and left for 6 days, leakage of the chemical solution is seen on the vacuum side (outside the degassing membrane). It was.

Claims (6)

In the hollow fiber membrane module in which the hollow fiber membrane is fixed and sealed using polyethylene or polypropylene ,
The material used for the sealing part of the module is polyethylene polymerized using a metallocene catalyst having a number average molecular weight (Mn) of 2000 or more and a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 3 or less. polypropylene Tona is,
The hollow fiber membrane is made of polyethylene or polypropylene,
The case material of the part in contact with the sealing part of the module is made of polyethylene or polypropylene polymerized using a metallocene catalyst having a weight average molecular weight to number average molecular weight ratio (Mw / Mn) of 2.0 to 5.0. A hollow fiber membrane module characterized by the above. The following relational expression
Softening point of hollow fiber membrane> Molding temperature ≧ Softening point of case member> Melting point of material used for sealing part
The hollow fiber membrane module according to claim 1 , wherein the sealing portion is molded at a molding temperature satisfying the above. In the hollow fiber membrane module in which the hollow fiber membrane is fixed and sealed using polyethylene or polypropylene ,
Part of the case material in contact with the sealing portion of the module, the number-average molecular weight (Mn) of 2,000 or more, the weight-average ratio of molecular weight to number average molecular weight (Mw / Mn) of 3 or less of polyethylene or polypropylene claim 1 or 3. The hollow fiber membrane module according to 2. The hollow fiber membrane module according to claim 3, wherein the material used for the sealing part of the module is polypropylene having a melting point (Tm) of 140 ° C or lower, or polyethylene having a melting point (Tm) of 120 ° C or lower. It is a method for manufacturing the hollow fiber membrane module as described in any one of Claims 1-4, Comprising: The molding temperature of a sealing part satisfy | fills the following relational expressions, The hollow fiber membrane module characterized by the above-mentioned. Production method.
Softening point of hollow fiber membrane> Molding temperature ≧ Softening point of case member> Melting point of material used for sealing part   The material used for the sealing part of the module is preheated at a temperature not higher than the melting point of the case member and not lower than the melting point of the material used for the sealing part to obtain a melt, and at least one of the bundles of hollow fiber membranes. 6. A step of impregnating the end portion with the melt, and a step of forming a sealing portion by heating at a temperature below the softening point of the hollow fiber membrane and above the melting point of the case member after the impregnation. The manufacturing method of the hollow fiber membrane module of description.