JP2008055304A - Hollow fiber membrane module and method of manufacturing hollow fiber membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing hollow fiber membrane modules which improves the durability of a hollow fiber membrane in the vicinity of a crawling-up part without damaging the initial performance of an effective membrane part, by improving the hollow fiber membrane of a hollow fiber membrane module. <P>SOLUTION: The hollow fiber membrane module which is formed by housing a hollow fiber membrane bundle bundling a plurality of hollow fiber membrane bundles each having a large number of pores opened on the outer surface in a case, and supporting and fixing the hollow fiber membrane bundle in the case with a potting material while remaining an effective membrane part 12; is provided with the crawling-up part 13 formed of the potting material and covering so as to crawl up on the outer surface of the hollow fiber membrane, and a filling part 14 formed of the potting material entering the pores, and forms an easily breakable part 18 on the interface between the crawling-up part 13 and the filling part 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hollow fiber membrane module using a hollow fiber membrane having a porous portion on the outer surface and a method for producing the hollow fiber membrane module.

Conventionally, a fluid filtration module, a gas-liquid separation module, and the like are known in which a plurality of hollow fiber membranes are housed in a case and the ends of the hollow fiber membranes are liquid-tightly fixed with a resin to form a hollow fiber membrane module. Yes.
For example, in Patent Document 1, the hollow fiber membrane positioned on the outer peripheral part of the hollow fiber membrane bundle at the time of manufacture does not adhere to the inner wall of the housing at a place other than the resin fixing part (hereinafter referred to as potting part), and leaks during use. A hollow fiber membrane module and a method for manufacturing the same are disclosed.

Moreover, in patent document 2, the stress of the hardening shrinkage of fixing resin (henceforth a potting material) does not concentrate on the hollow fiber membrane located in the outermost periphery of a hollow fiber membrane bundle, but the durability performance which can prevent a leak High hollow fiber membrane modules are provided.
And in patent document 3, the hollow fiber membrane module with high durability which can prevent the leak without the stress of the hardening shrinkage | contraction of a potting material being concentrated on the hollow fiber membrane located in the outermost periphery of a hollow fiber membrane bundle is provided. ing.
Patent Document 4 provides a method for manufacturing a highly reliable hollow fiber membrane separation module and a hollow fiber membrane separation module that can prevent stress from acting on the hollow fiber even when a thermal history is applied. Has been.
And in patent document 5, the hollow fiber membrane is distributed uniformly in a support member, and the manufacturing method of the highly reliable hollow fiber membrane module with respect to the fixing member of a hollow fiber membrane is provided.
JP 2001-276583 A JP 2000-229225 A JP-A-9-164324 JP-A-5-57155 JP-A-61-57206

  However, in the above-described conventional hollow fiber membrane module, in the fixing portion of the hollow fiber membrane bundle with the potting material, at the boundary between the hollow fiber membrane buried in the potting material and the effective membrane portion of the hollow fiber membrane retaining flexibility The concentration of stress is a limitation on the durability of the hollow fiber membrane. In addition, this phenomenon is more likely to occur at the outer periphery of the hollow fiber membrane bundle than at the radial center of the hollow fiber membrane bundle.

For this reason, for example, in Patent Document 1, in order to prevent the potting material before curing from creeping up between the inner wall surface of the case and the hollow fiber membrane by a capillary phenomenon, the hollow fiber membrane bundle of the resin fixing portion is converged and the case inner surface is A technique for spacing is disclosed. Moreover, in patent document 2, the method of arrange | positioning the space | interval with the inner surface of a case by arrange | positioning the stress relaxation agent which has elasticity between a resin fixing | fixed part and a hollow fiber membrane bundle for the same purpose as patent document 1 is disclosed.
However, in this case, the hollow fiber membrane filling rate of the fixed portion by the potting material of the hollow fiber membrane bundle is increased, and it becomes difficult for the potting material to enter. In order to prevent a sealing failure such as “su” from occurring due to this, it is necessary to lower the filling rate. In that case, a new problem such as an increase in the size of the module occurs in order to secure a necessary membrane area.

  Patent Document 3 discloses a technique for reinforcing a hollow fiber membrane by dissolving the thermoplastic resin in a solvent, immersing the hollow fiber membrane in the vicinity of the bundle fixing portion of the hollow fiber membrane bundle, and coating the hollow fiber membrane with the thermoplastic resin. Yes. However, in this case, at the time of using a thermoplastic resin that can be melted in a solvent, the hollow fiber membrane module manufactured by this method is used for chemicals, and the use of ultra-pure water etc. is extremely avoided. It becomes difficult to expand to.

  On the other hand, in Patent Document 4, in order to absorb the change in the length of the hollow fiber membrane when the thermal fluid is processed, the entire hollow fiber membrane bundle is heated and shrunk, and an effective hollow fiber membrane portion (hereinafter referred to as an effective membrane portion) is further reduced. A relaxation technique is disclosed. However, in the case of this method, the effective membrane portion is heated and shrunk, so that the surface open state of the hollow fiber membrane is changed, which affects the performance as a membrane such as filtration and separation.

  Patent Document 5 discloses a method of curling the hollow fiber membrane by heating the end portion of the hollow fiber membrane in order to facilitate the penetration of the potting material between the hollow fiber membranes. Is not disclosed.

  In view of the above circumstances, the present invention has been made as a result of intensive studies by the present inventors. The purpose is to improve the hollow fiber membrane and improve the durability of the hollow fiber membrane in the vicinity of the scooping portion without impairing the initial performance of the effective membrane portion.

  The hollow fiber membrane module of the present invention stores a hollow fiber membrane bundle in which a plurality of hollow fiber membranes having a large number of holes opened on the outer surface are bundled in a case, and the hollow fiber membrane bundle is an effective membrane by a potting material. A hollow fiber membrane module that is supported and fixed in the case leaving a portion, and a scooping portion formed by the potting material that covers the outer surface of the hollow fiber membrane so as to scoop up; And a filling portion formed by the potting material entering, and an easily breakable portion is formed at the interface between the scooping portion and the filling portion.

  By comprising in this way, when the external force of the longitudinal direction of a hollow fiber membrane is added to the scooping-up part, destruction of a potting material advances along the hollow fiber membrane surface located outside an easily breakable part. Thereby, the scooping up part escapes the restriction | limiting by a filling part, and extends | stretches following extension of the longitudinal direction of a hollow fiber membrane.

  Further, in the hollow fiber membrane module of the present invention, the diameter of the hole on the outer surface of the hollow fiber membrane covered by the scooping portion is smaller than the diameter of the hole on the outer surface of the effective membrane part. Features.

With this configuration, the area of the easily breakable portion, which is an interface between the scooping portion that covers the surface of the hollow fiber membrane and the filling portion that has entered the hole on the outer surface of the hollow fiber membrane, is reduced to the surface opening of the effective membrane portion. It can be made smaller than the pore area. Thereby, when a shearing force in a direction along the surface of the hollow fiber membrane is applied, the easily breakable portion easily shears and breaks along the surface of the hollow fiber membrane.
Therefore, as in the case of the above-described invention, when an external force in the longitudinal direction of the hollow fiber membrane is applied to the scooping portion, the potting material breaks down along the hollow fiber membrane surface located outside the easily breakable portion. Can do. Thereby, the scooping up part escapes the restriction | limiting by a filling part, and extends | stretches following extension of the longitudinal direction of a hollow fiber membrane.

  The method for producing a hollow fiber membrane module of the present invention includes a step of inserting a hollow fiber membrane bundle in which a plurality of hollow fiber membranes having a large number of holes opened on an outer surface are bundled into a case, and the hollow fiber membrane A hollow fiber membrane module manufacturing method comprising a step of supporting and fixing an end portion of a bundle in the case leaving an effective membrane portion with a potting material, the step of inserting the hollow fiber membrane bundle into the case; Between the step of supporting and fixing the hollow fiber membrane bundle in the case with the potting material, and having the step of heating the end of the hollow fiber membrane bundle covered with the potting material from the outside of the case. Features.

  By manufacturing in this way, the hollow fiber membrane at the end of the hollow fiber membrane bundle covered with the potting material is heated from the outside of the case, and the diameter of the hole on the outer surface of the hollow fiber membrane in the heated portion is contracted. be able to.

According to the present invention, when an external force in the longitudinal direction of the hollow fiber membrane is applied to the scooping up portion, the breakage of the easily breakable portion of the potting material proceeds along the hollow fiber membrane surface located outside the easily breakable portion. The scooping-up portion can be extended following the extension in the longitudinal direction of the hollow fiber membrane.
Therefore, it is possible to prevent breakage in the cross-sectional direction of the hollow fiber membrane at the scooping portion and improve the durability of the scooping portion.

Further, according to the present invention, in addition to the above-described effect, the easily breakable portion can be easily formed simply by reducing the diameter of the hole on the outer surface of the hollow fiber membrane covered by the scooping portion. Therefore, without lowering the productivity of the hollow fiber membrane module, it is possible to prevent the scooping portion from breaking in the cross-sectional direction of the hollow fiber membrane and improve the durability of the scooping portion.
Further, since the effective membrane portion of the hollow fiber membrane maintains the surface opening diameter that is appropriately designed to fulfill the function as a membrane, the membrane performance of the hollow fiber membrane can be maintained.

Moreover, according to this invention, only the part coat | covered with the potting part and the scooping part of the hollow fiber membrane outer surface can be heated, and the hole diameter of the outer surface of the part can be shrunk | reduced. Therefore, even with a single type of hollow fiber membrane, the same effect can be obtained only by simple heat treatment, and it is not necessary to develop a new membrane.
Moreover, since a simple heating process only needs to be added to the conventional manufacturing process, productivity is not reduced.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, in the hollow fiber membrane module 1, a hollow fiber membrane bundle 4 in which a plurality of thread-like hollow fiber membranes 3 having a hollow inside and having a membrane wall 2 are bundled is inserted into a cylindrical case 5. ing. In the membrane wall 2 of the hollow fiber membrane 3, as shown in FIG. 2, a large number of minute holes 8 are formed that open from the inner surface 6 to the outer surface 7. The hollow fiber membrane bundle 4 accommodated in the case 5 is supported and fixed inside the case 5 via a potting portion 10 formed of a potting material in a state where both ends of the hollow fiber membrane 3 are open.

  Here, the hollow fiber membrane 3 is manufactured by, for example, a melt spinning method and a stretch hole method using a polyethylene polymer as a raw material. Moreover, the surface opening diameter 11 of the hollow fiber membrane 3 is, for example, approximately 0.3 μm. Further, the potting material contains, for example, an epoxy resin as a main component. The material of the case 4 is selected depending on the processing fluid, and is, for example, a resin material such as polyethylene.

  Further, at the end of the hollow fiber membrane 3 that is liquid-tightly fixed inside the case 4 by the potting portion 10, as shown in FIG. 2, the hollow fiber membrane 3 embedded in the potting portion 10 and the effective membrane portion 12 A scooping portion 13 for covering the potting material so as to scoop up the outer surface 7 of the hollow fiber membrane 3 is formed therebetween. Further, the potting material covering the outer surface 7 of the hollow fiber membrane 3 enters a large number of surface openings 8 on the outer surface 7 of the hollow fiber membrane 3, and a filling portion 14 is formed in which the hole 8 is filled with the potting material. ing.

  Here, the surface aperture diameter 15 of the outer surface 7 of the hollow fiber membrane 3 covered with the scooping-up portion 13 is smaller than the surface aperture diameter 11 of the outer surface 7 in the effective membrane portion 12. For example, the surface aperture diameter 15 of the outer surface 7 of the hollow fiber membrane 3 covered with the scooping portion 13 is approximately 0.1 μm, and the surface aperture diameter 11 of the effective membrane portion 12 of the hollow fiber membrane 3 is approximately 0.3 μm. It is. The cross-sectional area along the outer surface 7 of the hollow fiber membrane 3 of the surface opening portion 17 is also reduced by the reduced diameter hole 16. An easily breakable portion 18 is formed at a cross section along the outer surface 7 of the hollow fiber membrane 3 of the surface opening portion 17 of the potting material, that is, at the interface between the scooping portion 13 and the filling portion 14.

  Next, functions and effects will be described. With the above configuration, as shown in FIG. 2, for example, when the tension in the longitudinal direction L of the hollow fiber membrane 3 is applied during the operation of the hollow fiber membrane module 1, the effective membrane portion 12 extends flexibly. At this time, the scooping up portion 13 also follows the hollow fiber membrane 3 and extends in the longitudinal direction L thereof. However, since the potting material is generally less flexible than the effective membrane portion 12, it tends to reach the limit of elongation before the effective membrane portion 12. Moreover, since the length of the filling part 14 in the longitudinal direction L of the hollow fiber membrane 3 is shorter than that of the climbing part 13 and the filling part 14, the relative elongation in the longitudinal direction L is higher than that of the climbing part 13. small. Therefore, the filling portion 14 reaches the limit of expansion before the scooping-up portion 13.

  Here, when the tension in the longitudinal direction L1 is applied to the hollow fiber membrane 103 shown in FIG. 3 and the hollow fiber membrane 103 expands, the scooping portion 113 also follows the hollow fiber membrane 103 and extends in the longitudinal direction L1. However, as described above, the expansion of the scooping portion 113 in the longitudinal direction L1 is restricted by the filling portion 114 that has reached the limit of expansion before the scooping portion 113. In the filling portion 114 that has reached the limit of elongation, the breakage proceeds in the cross-sectional direction C1 of the hollow fiber membrane 103 prior to the shear failure of the interface 118 between the scooping-up portion 113 and the filling portion 114. Accordingly, the scooping up portion 113 and the hollow fiber membrane 103 are also broken in the cross-sectional direction C <b> 1 of the hollow fiber membrane 103.

  However, in the present embodiment, as shown in FIG. 2, the surface opening diameter 15 of the portion covered with the scooping portion 13 of the outer surface 7 of the hollow fiber membrane 3 is larger than the surface opening diameter 11 in the effective membrane portion 12. Reduced diameter. Thereby, an easily breakable portion 18 is formed at the interface between the scooping portion 13 and the filling portion 14. That is, since the easily breakable portion 18 has a small cross-sectional area along the outer surface 7 of the hollow fiber membrane 3, shearing stress in a direction along the outer surface 7 of the hollow fiber membrane 3 causes a shear stress in the direction along the outer surface 7 of the hollow fiber membrane 3. Can be easily broken along.

  Therefore, when the hollow fiber membrane 3 is elongated by applying a tensile force in the longitudinal direction L to the hollow fiber membrane 3 shown in FIG. 2 by external force (including radial expansion caused by bending or internal pressure applied to the hollow portion) The rising portion 13 also follows the hollow fiber membrane 3 and extends in the longitudinal direction L thereof. And the expansion | extension of the longitudinal direction L of the scooping part is restrained by the filling part 14 which reached the limit of expansion | extension before the scooping part 13. However, at this time, the easily breakable portion 18 of the potting material is easily sheared along the outer surface 7 of the hollow fiber membrane 3. Thereby, the scooping-up part 13 can escape the restraint of the filling part 14, and can extend following the expansion | extension of the longitudinal direction L of the hollow fiber membrane 3. FIG.

  Therefore, when an external force in the longitudinal direction L of the hollow fiber membrane 3 is applied to the creeping portion 13 of the potting material, the potting along the outer surface 7 of the hollow fiber membrane 3 occurs when the potting material of the creeping portion 13 breaks. The destruction of the material can be advanced. Thereby, the flexibility of the hollow fiber membrane 3 in the longitudinal direction L at the scooping portion 13 is improved, and the durability of the hollow fiber membrane 3 in the vicinity of the scooping portion 13 is reduced without impairing the initial performance of the effective membrane portion 12. Can be improved.

Moreover, since the effective membrane part 12 of the hollow fiber membrane 3 maintains the surface opening diameter 11 appropriately designed to fulfill the function as a membrane, the membrane performance of the hollow fiber membrane 3 can be maintained. Further, when the potting material of the scooping portion 13 breaks, the breaking of the potting material can be advanced along the outer surface 7 of the hollow fiber membrane 3, so that the flexibility of the hollow fiber membrane 3 is impaired. It is possible to prevent the hollow fiber membrane 3 from being damaged. Accordingly, not only does the performance of the hollow fiber membrane 3 be impaired even if the breakage progresses, but also the liquid tightness of the potting portion 10 can be maintained.
Therefore, the durability of the hollow fiber membrane 3 in the vicinity of the scooping portion 13 can be improved without impairing the initial performance of the hollow fiber membrane 3.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. 4 with reference to FIG.
In FIG. 4, when forming the easily breakable portion 218, the entire hole 208 of the hollow fiber membrane 203 is not reduced in diameter, but the skeleton around the surface opening portion 217 is crushed so as to close the hole 208. Only the surface opening diameter 215 is reduced. Since other configurations are the same as those of the first embodiment, description thereof will be omitted.

  Here, as a method of forming the easily breakable portion 218, for example, there is a method of rubbing the outer surface 207 of the hollow fiber membrane 203 in a portion covered with the scooping portion 213 of the potting material. At this time, the portion covered with the scooping portion 213 of the potting material may be rubbed with the membranes or the friction member with a pressure that does not cause the holes 208 of the hollow fiber membrane 203 to be crushed. As a result, the skeleton of the hollow fiber membrane 203 around the surface opening portion 217 of the outer surface 207 of the hollow fiber membrane 203 can be crushed so as to close the hole 208. Therefore, only the surface opening diameter 215 can be reduced, and the easily breakable portion 218 as shown in FIG. 4 can be formed.

According to the second embodiment, as shown in FIG. 4, the cross-sectional area along the outer surface 207 of the hollow fiber membrane 203 of the easily breakable portion 218 can be reduced. Therefore, the easily breakable portion 218 can be easily broken along the outer surface 207 by the shear stress in the direction along the outer surface 207 of the hollow fiber membrane 203 generated by the tension in the longitudinal direction L2.
Therefore, when the tension in the longitudinal direction L2 is applied to the hollow fiber membrane 203 shown in FIG. 4 and the hollow fiber membrane 203 expands, the scooping portion 213 also follows the hollow fiber membrane 203 and extends in the longitudinal direction L2. And the expansion | extension of the longitudinal direction L2 of the scooping part 213 is restrained by the filling part 214 which reached the limit of expansion | extension before the scooping part 213. FIG. However, at this time, the easily-breakable portion 218 of the potting material easily shears and breaks along the outer surface 207 of the hollow fiber membrane 203. Thereby, the scooping-up part 213 can escape the restraint of the filling part 214, and can extend following the expansion | extension of the longitudinal direction L1 of the hollow fiber membrane 203. FIG.
Therefore, the same effect as the first embodiment can be obtained.

(Method for producing hollow fiber membrane module)
Next, the manufacturing method of the hollow fiber membrane module 1 in embodiment of this invention is demonstrated.

(Hollow fiber membrane bundle insertion process)
In the manufacture of the hollow fiber membrane module 1 shown in FIG. 1, first, the hollow fiber membrane bundle 4 is formed by bundling the hollow fiber membranes 3 described above. Next, the formed hollow fiber membrane bundle 4 is inserted into the cylindrical case 4.

(Hollow fiber membrane bundle heating process)
Next, the part covered with the potting material at the end of the hollow fiber membrane bundle 4 is heated.
As shown in FIG. 5, a heating container 20 is provided outside the case 5. The heating container 20 has a structure that covers only the end of the case 5. The heating container 20 is connected to a power source and a control device (not shown), and the hollow fiber membrane bundle 4 inside the case 5 can be heated to an arbitrary temperature by a heater (not shown). Moreover, the arbitrary length of the edge part of the hollow fiber membrane bundle 4 can be heated by adjusting the width | variety which the heating container 20 covers the case 4. FIG.

Using this heating container 20, the end of the hollow fiber membrane bundle 4 housed inside the case 5 is heated from the outside of the case 5. By heating, the hollow fiber membrane 3 contracts, and the surface opening diameter 15 becomes small. The width of the end portion to be heated and shrunk may be only the width covered with the potting material when modularized, and one end portion or both end portions may be appropriately heat-shrinked.
The heating method can be selected as appropriate, such as a method in which the end portion is dry-heated with the heating container 20 or a method in which only the end portion is immersed in a liquid and wet-heated in the heating container 20.

  In the case of dry heating, there is no concern about contamination of the hollow fiber membrane 3 and the heating device 20 is simple. However, since the air in the hollow fiber membrane bundle 4 acts as a heat insulating material, the radial direction center direction of the hollow fiber membrane bundle 4 Only the outer peripheral portion of the hollow fiber membrane bundle 4 is reduced in surface opening diameter 15 by heat shrinkage. Therefore, when the diameter of the hollow fiber membrane bundle 4 is small, the dry heating method is preferred when only the outer periphery of the hollow fiber membrane bundle 4 needs to have a small surface opening diameter of 15.

  On the other hand, in the case of wet heating, since heat is transmitted by the liquid, heat is also easily transmitted to the central portion in the radial direction of the hollow fiber membrane bundle 4, and the reduction of the surface opening diameter 15 due to heat shrinkage is the radial direction of the hollow fiber membrane bundle 4. Can affect up to the center. The type of liquid at this time may be a liquid having a boiling point equal to or higher than the heating temperature of the hollow fiber membrane bundle 4. For example, a heat medium such as pure water, silicon oil, or polyethylene glycol can be used as appropriate. Moreover, when pure water is used, it is excellent in safety | security, handleability, and cleanliness, and preferable.

  In applications where the cleanliness of the hollow fiber membrane 3 is required and the shrinking temperature is higher than the boiling point of pure water, for example, it is possible to wash later using a high boiling point liquid such as silicon oil or polyethylene glycol. . Further, even when pure water is used, partial heating up to 150 ° C. can be performed by heating water in, for example, a 4.7 atmosphere pressure space.

  Furthermore, when performing wet heating, it is preferable to carry out below the boiling point of the liquid to heat. In a boiled state, evaporation occurs on the surface other than the surface of the liquid, so that the volume of the liquid expands and heat may be transmitted beyond the range to be heated.

(Hollow fiber membrane bundle support and fixing process)
Next, a portion of the end portion of the hollow fiber membrane bundle 4 accommodated in the case 5 in which the surface opening diameter 15 of the outer surface 7 of the hollow fiber membrane 3 is reduced by the overheating process is formed inside the case 5 with a potting material. Support and fix to.
The end of the hollow fiber membrane bundle 4 accommodated in the case 5 is supported and fixed to the inside of the case 5, for example, between the ends of the hollow fiber membranes 3 constituting the hollow fiber membrane bundle 4. It is performed by filling a potting material from the opening of the part. At this time, the potting material is filled so that the scooping portion 13 is within the range of the end portion of the heat-treated hollow fiber membrane 3 with the effective membrane portion 12 remaining.

Here, the function and effect will be described.
According to the manufacturing method of the present embodiment, the end of the hollow fiber membrane bundle 4 can be heated while the hollow fiber membrane bundle 4 is inserted into the case 5. Further, the end portion can be fixed as it is without removing the hollow fiber membrane bundle 4 from the case after the heating step.
Therefore, it is only necessary to add a simple heating process between the process of inserting the hollow fiber membrane bundle 4 into the case 5 and the process of supporting and fixing the hollow fiber membrane bundle 4 in the case with the potting material. It does not deteriorate the sex.

In addition, by using one type of hollow fiber membrane 3 and heating the end of the hollow fiber membrane bundle 4 from the outside of the case 5, the surface opening diameter 15 of the portion covered by the scooping portion 13 due to thermal contraction is effective. It can be made smaller than the surface opening diameter 11 of the film part 12.
Therefore, it is not necessary to newly develop a film having two types of surface opening diameters 11 and 15.

In addition, when the end of the hollow fiber membrane bundle 4 is heated before insertion into the case 5 to reduce the surface opening diameter 15 of the hollow fiber membrane 3 in the portion covered by the scooping portion 13, the hollow fiber membrane bundle 4 is hollow. Since the yarn membrane 3 is crimped by heat shrinkage, the hollow fiber membrane bundle 4 becomes bulky in the radial direction, and insertion into the case 5 becomes difficult.
However, when the hollow fiber membrane bundle 4 is inserted into the case 5 and then heated, it can be inserted into the case 5 before being bulked by heating. Therefore, the hollow fiber membrane bundle 4 can be easily inserted into the case.

Further, the surface opening diameter 15 of the hollow fiber membrane 3 in the portion covered with the rising portion 13 of the potting material is smaller than the surface opening diameter 11 of the effective membrane portion 12. That is, the surface opening diameter 11 of the portion related to the function of the membrane such as separation, permeation, and filtration is the required surface opening diameter 11, but the portion that contacts the potting material has a small surface opening diameter 15.
Therefore, it is possible to prevent damage to the hollow fiber membrane 3 in the scooping portion 13 while maintaining the performance as the hollow fiber membrane 3.

 In the above-described embodiment, a method of reducing the surface opening diameter of the outer surface of the hollow fiber membrane of the portion covered by the scooping portion using one type of hollow fiber membrane has been described. It is also possible to apply to a method in which two types of membranes are used, and the surface aperture diameter of the hollow fiber membrane in the portion close to the inner surface of the case is made small.

That is, a method of bundling a hollow fiber membrane having a surface opening diameter suitable for the use of the hollow fiber membrane module and winding a hollow fiber membrane bundle having a small surface opening diameter around the outer periphery thereof can be employed.
It is also possible to provide a hollow fiber membrane layer having a small surface opening diameter only on the resin fixing portion.
These are methods in which a hollow fiber membrane layer having a surface opening diameter smaller than the hollow fiber membrane surface opening diameter of the hollow fiber membrane bundle is wound around the outer periphery of the hollow fiber membrane bundle having a required surface opening diameter.

Here, the hollow fiber membrane can be handled as a bundle of hollow fiber membranes called a wound or bundle, but one or more hollow fiber membrane filaments are folded back multiple times with a certain width, and the folded portion is used as a constraining yarn. When handled as a hollow fiber membrane sheet, generally called a Russell knitted fabric, obtained by restraining it, it is excellent in terms of workability.
That is, according to the present invention, a hollow fiber membrane bundle can be produced using two types of hollow fiber membranes having different surface aperture diameters, or the surface aperture diameter can be partially reduced using one type of hollow fiber membrane. It is also possible to do.

  Moreover, as a method of inserting a hollow fiber membrane bundle in which the surface opening diameter of the hollow fiber membrane present in the scooping portion is smaller than the other portions into the case, it is not particularly caught, and two types of hollow fiber membranes When the hollow fiber membrane layer having a small surface opening diameter is provided on the outer periphery of the hollow fiber membrane bundle using the knitted fabric, the raschel knitted fabric of the hollow fiber membrane bundle and the raschel knitted fabric of the hollow fiber membrane layer are continuously knitted, or By connecting to form a hollow fiber membrane wound body comprising a hollow fiber membrane bundle and a hollow fiber membrane layer, the hollow fiber membrane can be prevented from shifting when the case is inserted.

  The hollow fiber membrane may be a homogeneous membrane in which fine pores are distributed almost uniformly in the film thickness direction, or an asymmetric membrane having a dense layer on the membrane surface.

Further, since the hollow fiber membrane embedded in the potting material does not deform even when an external force is applied, the surface opening diameter of this portion may be equal to that of the effective membrane portion. That is, it is only necessary that the surface opening diameter of the hollow fiber membrane at least in the portion covered by the scooping portion is smaller than the surface opening diameter of the hollow fiber membrane existing in the other portion.
In addition, since the amount of creeping up of the potting material is difficult to control precisely due to the density of the hollow fiber membranes and the flow before the potting resin is cured, the surface pore diameter in the longitudinal direction of the hollow fiber membranes can be reduced. It is safe to reduce the diameter of the hole until there is a possibility of creeping up.

  Further, with respect to the radial direction of the hollow fiber membrane bundle of the hollow fiber membrane module, the hollow fiber membrane breakage points are concentrated in the vicinity of the case and the outer peripheral part of the hollow fiber membrane bundle. A certain effect can be obtained if the surface opening diameter of the hollow fiber membrane existing in the outer peripheral portion of the bundle is smaller than the surface opening diameter of the hollow fiber membrane existing in the other portion, but the durability of the outer periphery is improved. However, since there is a high possibility that the hollow fiber membrane will be damaged at the further inner side, the pore diameter is preferably reduced to the center in the radial direction of the hollow fiber membrane bundle.

  Moreover, in the above-mentioned embodiment, although the cross-sectional shape of the hollow fiber membrane bundle and the hollow fiber module was represented as a cylindrical shape, the cross-sectional shape can be appropriately selected such as a rectangular shape or a flat shape.

  The material of the hollow fiber membrane may be any material having flexibility, for example, a polyolefin-based polymer such as polyethylene, polypropylene, poly (3-methylbutene-1), poly (4-methylpentene-1), Fluorine polymers such as polyvinylidene fluoride and polytetrafluoroethylene, and polymers such as polystyrene, polyether ether ketone, and polyether ketone can be used.

The potting material is not particularly limited, and a thermosetting resin, a thermoplastic resin, or the like can be appropriately selected and used. For example, a thermosetting resin such as a urethane resin, an epoxy resin, or a silicon resin is used. If so, the effects of the present invention tend to be obtained more suitably.
In particular, when a potting material that is a combination of a hollow fiber membrane material and a flexible opening is selected, a particularly great effect can be obtained. For example, in the case of a hollow fiber membrane module for processing a chemical solution, a potting resin having high chemical resistance is generally a material having a low flexibility and a hard material. Demonstrate great effect.

  That is, according to the present invention, when selecting the hollow fiber membrane and the potting material of the hollow fiber membrane module, even if the basic performance of each member is selected as a main component, the hollow fiber membrane at the rising portion of the potting material is prevented from being damaged. And the range of member selection can be greatly expanded.

The present inventors made a sample in which a hollow fiber membrane surface was coated with a potting material in order to clarify the breakage behavior of the scooping portion, and conducted the following experiment.
For details of the experiment, polyethylene three-layer composite hollow fiber membrane MHF200TL (manufactured by Mitsubishi Rayon Engineering Co., Ltd.) was subjected to no heat treatment, 80 ° C dry heat treatment, 120 ° C dry heat treatment, and each three-layer composite hollow fiber A total of 6 samples were prepared, one for each film coated with an epoxy resin and solidified, and the other uncoated. The strength and elongation were measured under the following conditions.
Further, the hollow fiber membrane shrinkage rate at 80 ° C. dry heat treatment was 6% and the surface pore diameter was 0.1 μm, the hollow fiber membrane shrinkage rate at 120 ° C. dry heat treatment was 40%, and the surface pore diameter was 0.05 μm. It was. The hole diameter of the hollow fiber membrane surface before the heat treatment was 0.1 μm.
The strength elongation measurement conditions were a test length of 50 mm, a head speed of 50 mm, a measurement environment temperature of 20 ° C., and a measurement environment humidity of 65% RH.
FIG. 6 shows the values of the strength and elongation after coating, with 100 as the uncoated sample for each of the heat treatment, 80 ° C. treatment and 120 ° C. treatment. In FIG. 6, the breaking strength is represented as a white column and the breaking elongation is represented as a black column. In the figure, “-” represents “no coating” or “no heat treatment”.

As shown in FIG. 6, the breaking strength of all samples is constant regardless of the presence or absence of coating, whereas the breaking elongation is extremely low for products without dry heat treatment and with 80 ° C. dry heat treatment coating. Yes. On the other hand, with respect to the 120 ° C. dry heat-treated product, the elongation at break does not decrease due to the presence or absence of coating.
The above-mentioned results of the measurement of high elongation show that when the coating layer is not subjected to dry heat treatment and with 80 ° C dry heat treatment, the hollow fiber membrane also breaks simultaneously when the coating layer breaks, whereas the 120 ° C dry heat treatment product breaks when the coating layer breaks. This also shows that the hollow fiber membrane exhibits the elongation at break while maintaining the shape of the hollow fiber membrane.

  In addition, as for the preferable range of the hollow fiber membrane surface opening diameter of the scooping up part, as described above, a sample imitating the scooping up part of the potting material was prepared, and from the measurement result of the high elongation, A method of finding a surface opening diameter with little change is reliable and preferable. At this time, a sample imitating the potting material scooping part was also prepared by contacting the fluid actually used in the hollow fiber membrane module for a certain period of time. A more preferable surface opening diameter can be selected in consideration of the influence of deterioration such as swelling, dissolution and embrittlement of the material. Of course, the present inventors will continue to study diligently, and the material and rigidity of the potting material, the thickness covering the surface of the hollow fiber membrane, the material and film thickness of the hollow fiber membrane, the surface opening diameter, the porosity, and each member Needless to say, a preferable surface opening diameter, which is a design matter, is clarified in consideration of related factors such as durability against the fluid used.

  A polyethylene porous hollow fiber membrane EX270T (manufactured by Mitsubishi Rayon Engineering Co., Ltd.) was heat-treated, and the strength and elongation of what was coated with a urethane resin were measured. Table 1 shows the values of the breaking elongation after coating, with the breaking elongation of the hollow fiber membrane only by heat treatment being 100. Table 1 also shows changes in the shrinkage rate, porosity, and surface pore diameter of the hollow fiber membrane due to heat treatment as a reference.

From the breaking elongation in Table 1, it can be seen that there is no decrease in breaking elongation at 120 ° C. by dry heat treatment.
Next, a hollow fiber membrane bundle of EX270T was prepared, inserted into the heating container shown in FIG. 5, and the end of the hollow fiber membrane bundle was heated at 120 ° C. to obtain a hollow fiber membrane bundle having an outer diameter of 40 mm and a length of 110 mm. Obtained. At this time, the heating width of the hollow fiber membrane was 35 mm, and the length of the hollow fiber membrane bundle before heating was 163 mm in anticipation of the shrinkage rate.
The obtained hollow fiber membrane bundle was potted with a urethane resin into a cylindrical case having a length of 110 mm and an inner diameter of 40 mm, and the potting end portion was cut by 10 mm to open the hollow portion of the hollow fiber membrane bundle, and water was added to both ends of the case. An inlet / outlet was attached to obtain a hollow fiber membrane module.
The filling rate of the hollow fiber membrane in the case was 45%, the length of all hollow fiber membranes embedded in the potting material was 10 mm, and the creeping portion was 0 mm to 10 mm.
Since the heating width is 35 mm, it can be seen that all the portions where the potting material and the film are in contact with each other including the creeping portion are heated. The hollow fiber membrane had an inner diameter of 270 μm, an outer diameter of 380 μm, and an effective membrane area of 0.5 m ² .
Water was passed from the hollow fiber membrane outer surface side of the obtained hollow fiber membrane module, and the filtration flow rate was measured and found to be 18 L / min · 0.1 MPa.

[Comparative Example 1]
An EX270T hollow fiber membrane bundle was prepared, and the entire hollow fiber membrane bundle was heated at 120 ° C. to obtain a hollow fiber membrane bundle having an outer diameter of 40 mm and a length of 110 mm. Using the obtained hollow fiber membrane bundle, a hollow fiber membrane module was produced in the same manner as in Example 2, and the filtration flow rate was measured and found to be 3 L / min · 0.1 MPa.

[Reference Example 1]
A hollow fiber membrane bundle having an outer diameter of 40 mm and a length of 110 mm was obtained using EX270T. Using the obtained hollow fiber membrane bundle, a hollow fiber membrane module was produced in the same manner as in Example 1, and the filtration flow rate was measured. As a result, it was 18 L / min · 0.1 MPa.
As is clear from Example 2, Comparative Example 1 and Reference Example 1, the hollow fiber membrane module has a surface pore diameter reduced only at the potting portion, so the basic performance as a module, in this case, the filtration flow rate is impaired. It will not be.

  A polyethylene three-layer composite hollow fiber membrane MHF200TL (manufactured by Mitsubishi Rayon Engineering Co., Ltd.) was heat-treated, and the tensile strength of the coated with an epoxy resin was measured. Table 2 shows the values of the elongation at break after coating when the elongation at break of the hollow fiber membrane only by heat treatment is taken as 100. In Table 2, changes in the shrinkage rate, porosity, and surface pore diameter of the hollow fiber membrane due to heat treatment are also described for reference.

From the breaking elongation in Table 2, it can be seen that there is no decrease in breaking elongation at 120 ° C. by dry heat treatment.
Next, a hollow fiber membrane bundle of MHF200TL is prepared, inserted into the heating container shown in FIG. 5, the end of the hollow fiber membrane bundle is heated at 120 ° C., and the opposite end is similarly heated at 120 ° C. Heating was performed to obtain a hollow fiber membrane bundle having an outer diameter of 40 mm and a length of 120 mm.
At this time, the heating width of the hollow fiber membrane was 35 mm, and the length of the hollow fiber membrane bundle before heating was 176 mm in anticipation of the shrinkage rate. The hollow fiber membrane bundle thus obtained was potted on a cylindrical case having a length of 120 mm and an inner diameter of 40 mm with epoxy resin at both ends of the hollow fiber membrane bundle, and the potting end portion was cut by 10 mm to open the hollow portion of the hollow fiber membrane bundle. A hollow fiber membrane module was obtained.
The portion corresponding to the effective membrane portion of the case is provided with a plurality of slits, the filling rate of the hollow fiber membrane in the case is 45%, and the length of all hollow fiber membranes embedded in the potting material is 10 mm. The rising part was 0 mm to 10 mm. Since the heating width is 35 mm, it can be seen that all the portions where the potting material and the film are in contact with each other including the creeping portion are heated. The hollow fiber membrane had an inner diameter of 270 μm, an outer diameter of 380 μm, and an effective membrane area of 0.6 m 2.
Water inlets and outlets are attached to both ends of the obtained hollow fiber membrane module, water is poured into the space leading to the inside of the hollow fiber membrane, the water is filled, the water outlet is closed, and water pressure is increased from the water inlet. The pressure resistance test was repeated repeatedly. The portion of the hollow fiber membrane where the potting resin was not applied was damaged after the pressure was increased 230,000 times. The conditions of the repeated pressure test were as follows. The pressing pressure was 0.35 MPa, the pressing time was 10 seconds, the pressure release time was 10 seconds, and the temperature was 40 ° C.

[Comparative Example 2]
A hollow fiber membrane bundle of MHF200TL was produced, a hollow fiber membrane module was produced in the same manner as in Example 2 without any heat treatment, and repeated pressure resistance tests were conducted. The hollow fiber membrane was damaged.
As is clear from Example 3 and Comparative Example 2, the potting resin scooping portion can be prevented from being damaged, so that the life can be extended.

It is a schematic sectional drawing of the hollow fiber membrane module which concerns on the 1st Embodiment of this invention. FIG. 2 is a partially enlarged schematic cross-sectional view in the vicinity of a scooping portion in FIG. 1. It is a partial expansion schematic sectional drawing in the vicinity of the creeping-up part of the conventional hollow fiber membrane module. It is a partial expanded schematic sectional drawing in the vicinity of the scooping part which concerns on the 2nd Embodiment of this invention. It is a schematic perspective view of the heating process which concerns on embodiment of this method invention. It is a figure which shows the change rate of the strong elongation of Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane module 3 Hollow fiber membrane 4 Hollow fiber membrane bundle 5 Case 7 Outer surface 8 Hole 11 Surface opening diameter (The diameter of the hole of the outer surface of an effective membrane part)
12 Effective membrane part 13 Scooping part 14 Filling part 15 Surface opening diameter (hole diameter) of the outer surface of the hollow fiber membrane covered with the scooping part
18 Easy break

Claims (3)

A hollow fiber membrane bundle in which a plurality of hollow fiber membranes having a large number of holes opened on the outer surface are bundled is accommodated in the case, and the hollow fiber membrane bundle is supported in the case leaving an effective membrane portion by a potting material. A hollow fiber membrane module that is fixed,
The scooping portion formed by the potting material that covers the outer surface of the hollow fiber membrane so as to scoop up, and the filling portion formed by the potting material that enters the hole, the scooping portion and the filling portion A hollow fiber membrane module characterized in that an easily breakable part is formed at the interface with the hollow fiber membrane module.   The hollow fiber membrane according to claim 1, wherein the diameter of the hole on the outer surface of the hollow fiber membrane covered by the scooping portion is smaller than the diameter of the hole on the outer surface of the effective membrane portion. module. A step of inserting a hollow fiber membrane bundle in which a plurality of hollow fiber membranes having a large number of holes opened on the outer surface are bundled into a case, and leaving an effective membrane portion at the end portion of the hollow fiber membrane bundle with a potting material A method for producing a hollow fiber membrane module comprising a step of supporting and fixing in the case,
The hollow fiber membrane bundle covered with the potting material between the step of inserting the hollow fiber membrane bundle into the case and the step of supporting and fixing the hollow fiber membrane bundle in the case with the potting material A method of manufacturing a hollow fiber membrane module, comprising a step of heating an end of the hollow fiber from the outside of the case.

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