JP4755484B2 - Hollow fiber membrane composite nozzle and method for producing composite hollow fiber membrane - Google Patents

Description

  The present invention provides a hollow fiber membrane composite capable of obtaining high spinning stability and stable membrane quality when a membrane-forming raw solution is spun into a hollow porous substrate in the production process of the composite hollow fiber membrane. The present invention relates to a nozzle and a method for producing a composite hollow fiber membrane.

  In recent years, due to increasing interest in environmental pollution and stricter regulations, water treatment by a membrane method using a filtration membrane having excellent separation completeness and compactness has attracted attention. In such water treatment applications, filtration membranes are required not only to have excellent separation characteristics and permeation performance, but also to have higher mechanical properties than ever before.

  In such a demand, Japanese Patent Application Laid-Open No. 5-7746 (Patent Document 1) discloses a method for producing a porous filtration membrane excellent in pressure resistance by passing a round string through a liquid immersion bath to remove bubbles. After that, a string-like porous membrane is manufactured by extruding the spinning string and the spinning solution made of a phase-separable membrane-forming resin from a double annular nozzle and spinning by a wet or dry wet spinning method. Manufacturing methods have been proposed.

  In addition, International Publication No. 2004/43579 pamphlet (Patent Document 2) provides not only filtration performance but also a composite porous membrane with excellent adhesion between the porous membrane and braid and excellent mechanical properties. In order to achieve this, a porous layer having a dense layer is formed in the thickness direction of the membrane by a composite spinning by a wet or dry-wet spinning method using a spinning stock solution made of a film forming resin that can be phase-separated with a hollow braided braid. In addition, a composite porous membrane formed on the outer surface of the braid with two or more layers has been proposed.

  If such a composite porous film having two or more porous layers is formed, for example, a porous layer having excellent adhesion to the braid outer surface is formed as the first layer, and a void is formed as the second layer. By forming a porous layer having a small amount and excellent mechanical strength, a composite porous membrane having excellent adhesion between the porous layer and braid and excellent mechanical properties can be obtained. Further, this composite porous membrane is said to be excellent in durability of the porous layer because each of the two or more porous layers has a dense layer.

  Furthermore, in this patent document 2, the said composite porous membrane is manufactured using the double annular nozzle. In this double annular nozzle, in order to prevent a gap between the porous layers formed on the outer surface of the braid, the inner tube discharge tip is arranged inward of the outer tube discharge tip so as to prevent the liquid seal. Has been done.

On the other hand, in Japanese Patent Application Laid-Open No. 2004-314059 (Patent Document 3), when coating a polymer solution (spinning stock solution) on a hollow fiber membrane serving as a support, a coating defect caused by the outer diameter shape of the hollow fiber membrane, A method for reducing yarn jamming has been proposed. Specifically, in the nozzle that coats the polymer solution onto the hollow fiber membrane, the outlet port forming member is made of an elastic member, and when the composite hollow fiber membrane is manufactured using the nozzle, the outlet port of the nozzle is formed. It is possible to make the coating thickness of the polymer solution uniform by changing the following in accordance with the outer diameter shape of the hollow fiber membrane. As a result, even if the outer diameter of the hollow fiber membrane used as the support membrane is not uniform in the length direction, it is possible to prevent defective coating of the polymer solution and the occurrence of defective products, and reduce yarn clogging. It can also be done.
JP-A-5-7746 International Publication No. 2004/43579 Pamphlet JP 2004-314059 A

  However, according to the manufacturing method of the string-like porous film described in Patent Document 1, in order to remove the air existing inside the round string (support base material), the round string is made of polypropylene glycol or the like. Defoaming is carried out by dipping in the liquid. However, in Patent Document 1, no special consideration is given to the spinning of the spinning dope made of a film-forming resin on the defoamed round string. In some cases, air (gas) was caught between the spinning dope. In this way, if air is caught between the round string and the spinning dope, or if air grows on the die discharge surface, an abnormality occurs in the outer diameter portion of the obtained composite hollow fiber membrane. There is a problem that it occurs or a porous film is locally thinned, making it difficult to obtain a product having stable quality.

  Further, according to the method for producing a composite porous membrane of Patent Document 2, the sealing property may change depending on the setting of the sealing pressure in the liquid seal and the shape of the braid of the hollow round punch, and there is a risk of entraining air. For this reason, defects may occur in the porous film formed on the hollow round braid.

  On the other hand, in the method for producing a composite hollow fiber membrane using the coating nozzle described in Patent Document 3, depending on the shape and state of the introduced hollow fiber membrane, the viscosity of the polymer solution, etc., the hollow fiber membrane and the polymer solution At the time of contact, air is entrained between the two, which is one of the factors that cause defects in the composite hollow fiber membrane. However, Patent Document 3 does not give any special consideration for preventing the entrainment of air, and has the same problem as Patent Document 1.

  The present invention has been made in view of the above problems, and its specific purpose is that in the production of a composite hollow fiber membrane, gas is involved in the composite portion of the hollow porous base material and the membrane forming stock solution. Hollow fiber membrane composite nozzle and composite capable of obtaining stable spinning and membrane quality by inhibiting and preventing the occurrence of abnormal outer diameter due to gas entrainment and membrane defect due to local thinning It is providing the manufacturing method of a hollow fiber membrane.

In order to achieve the above-mentioned object, the hollow fiber membrane composite nozzle provided by the present invention has a basic configuration in which a membrane-forming stock solution capable of forming a porous membrane is composite-spun on the peripheral surface of a hollow porous substrate. A hollow fiber membrane composite nozzle having an annular structure to obtain a hollow fiber membrane, wherein the hollow porous membrane is formed inside the annular membrane-forming solution discharge port for discharging the membrane-forming stock solution and inside the membrane-forming stock solution discharge port A base material discharge port for discharging the base material is arranged apart from each other, and the hollow porous base material, the film forming stock solution, the hollow porous base material and the film forming stock solution discharged from each discharge port at the time of composite spinning Having an opening formed toward the space between the film forming stock solution discharge port and the base material discharge port, and the opening and the atmosphere release unit or an external ventilation source The main feature is that a gas communication path is formed to communicate with the connection port connected to Than is.

  Moreover, it is preferable that the inner lower end surface and the outer lower end surface of the nozzle portion adjacent to the film-forming stock solution discharge port are on the same plane.

Furthermore, the cross-sectional area of the travel path in which the hollow porous base material of the hollow fiber membrane composite nozzle travels is set to be larger than the cross-sectional area of the hollow porous base material, and the gas communication path is formed of the travel path. A gap between the inner wall surface and the outer peripheral surface of the hollow porous substrate is preferable.

  Further, in the present invention, an inlet for introducing the hollow porous base material into the upper part of the hollow fiber membrane composite nozzle, and an auxiliary liquid supply port for supplying a film forming auxiliary liquid to the peripheral surface of the hollow porous base material And a confluence plate provided with a lead-out port for feeding out the hollow porous substrate to which the film forming auxiliary liquid is applied.

  Furthermore, it is preferable to have an introduction plate for positioning the traveling position of the hollow porous substrate above the hollow fiber membrane composite nozzle.

Next, the method for producing a composite hollow fiber membrane according to the present invention uses the hollow fiber membrane composite nozzle having the above-described configuration to merge and integrate the hollow porous base material and the membrane forming stock solution. The integrated hollow porous base material and film-forming stock solution are immersed in a coagulating liquid and solidified.

  The hollow fiber membrane composite nozzle according to the present invention includes an annular film-forming stock solution discharge port that discharges a film-forming stock solution, and a substrate discharge port that is formed inside the film-forming stock solution discharge port and discharges a hollow porous substrate. Are spaced apart, and has an opening formed toward the space between the hollow porous base material, the membrane-forming stock solution, and the confluence of the hollow porous base material and the membrane-forming stock solution, A gas communication path is formed to communicate the opening and the connection port connected to the atmosphere release section or the external ventilation source.

  As a result, the gas accompanying the hollow porous substrate moves to the space when discharged from the nozzle, and then can be quickly discharged to the outside from the connection port via the gas communication path. Occasionally, gas can be prevented from intervening between the hollow porous substrate and the film-forming stock solution, and gas growth can be suppressed.

  Therefore, according to the hollow fiber membrane composite nozzle of the present invention, it is possible to suppress the entrainment of gas between the hollow porous base material and the membrane forming stock solution as described above, so that stable spinning can be performed for a long time. In addition, the composite-spun composite hollow fiber membrane does not generate a membrane defect mainly due to entrainment of gas and stably has good quality.

  In the present invention, the “annular structure” refers to an inner closed line segment and an outer closed line segment that do not contact the shape of the discharge port of the membrane forming raw solution when viewed from the discharge port of the hollow fiber membrane composite nozzle. This is a double-lined structure composed of a cylindrical shape that is parallel to the double-line shape in the depth direction in the vicinity of the discharge port and whose cross-sectional area does not change.

  In the hollow fiber membrane composite nozzle of the present invention, the inner lower end surface and the outer lower end surface of the nozzle portion adjacent to the film forming raw solution discharge port are on the same plane perpendicular to the discharge direction of the film forming raw solution. For this reason, the film-forming stock solution can be released simultaneously from the internal and external flow resistance portions constituting the flow path of the film-forming stock solution, and the film-forming stock solution can be stably discharged in a cylindrical shape at a predetermined discharge linear velocity. Thereby, the membrane forming undiluted solution has high followability to the hollow porous substrate and can obtain a stable membrane shape.

  Furthermore, the hollow fiber membrane composite nozzle of the present invention has the opening in the nozzle portion between the membrane-forming stock solution discharge port and the base material discharge port, and the opening and the connection port are the gas communication path. It is communicated. Thereby, the gas which intervenes in the space formed between a hollow porous base material and a film-forming stock solution at the time of composite spinning can be easily discharged from the connection port via the gas communication path.

  Further, in the present invention, the cross-sectional area of the travel path in which the hollow porous base material of the hollow fiber membrane composite nozzle travels is set larger than the cross-sectional area of the hollow porous base material, A gap between the outer peripheral surfaces of the porous substrate serves as a gas communication path. The hollow fiber membrane composite nozzle having such a configuration is excellent in processability, economy (cost), and operability of the hollow fiber membrane composite nozzle, and the hollow porous substrate and the membrane forming stock solution after discharge In addition to the space formed between the hollow porous base material and the gap formed in the travel path of the hollow porous base material can be regarded as the same space, the gas accompanying the hollow porous base material can be more effectively externalized. Can be discharged. For this reason, gas interposition between the hollow porous substrate and the membrane-forming stock solution and gas growth can be more reliably suppressed during composite spinning, and a high-quality composite hollow fiber membrane can be produced.

  Furthermore, in this invention, it has the confluence | merging plate which can provide a film | membrane formation auxiliary | assistant liquid to the surrounding surface of a hollow porous base material in the upper part of a hollow fiber membrane composite nozzle. Thus, for example, in the case of performing multilayer structure spinning in which a hollow porous base material is formed in advance and then formed again, or in the case of performing pretreatment of the hollow porous base material in advance. The membrane formation auxiliary liquid can be stably applied to the hollow porous substrate before the membrane stock solution is combined with the hollow porous substrate.

  Moreover, in this invention, it has the introduction plate which positions the running position of a hollow porous base material on the upper part of a hollow fiber membrane composite nozzle. This makes it possible to set the traveling position of the hollow porous base material to a predetermined position and perform spinning stably, and prevent the hollow porous base material from being misaligned. A yarn membrane can be obtained.

Furthermore, the method for producing a composite hollow fiber membrane of the present invention comprises using the hollow fiber membrane composite nozzle to discharge the hollow porous substrate from the nozzle and to form the membrane so as to surround the entire circumference of the hollow porous substrate. The stock solution is discharged in a cylindrical shape at a predetermined discharge linear velocity, and the hollow porous substrate and the film forming stock solution are merged and integrated. Then, a composite hollow fiber membrane is manufactured by immersing and solidifying the integrated hollow porous base material and membrane-forming stock solution in a coagulating solution. Thereby, when the hollow porous substrate is discharged from the nozzle, the gas accompanying the hollow porous substrate is also discharged from the discharge port, and then from the connection port via the gas communication path formed in the nozzle. It can be discharged quickly to the outside. Accordingly, it is possible to stably produce a composite hollow fiber membrane by suppressing gas entrainment between the hollow porous base material and the membrane forming stock solution and gas growth caused by the entrainment of the gas, and an abnormal outer diameter. The composite hollow fiber membrane having a uniform film thickness and good film quality can be obtained.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
In the present invention, the hollow porous substrate has one or more hollow portions communicating in the longitudinal direction in the cross section perpendicular to the longitudinal direction of the substrate, and the fluid moves from the outer peripheral surface of the substrate to the hollow portion. Further, any shape can be used as long as it can move in the longitudinal direction, and the cross-sectional shape of the hollow portion and the cross-sectional outer peripheral shape of the base material may be any shape such as a circular shape or an irregular shape. In addition, the cross-sectional shape of the hollow portion and the base material may be the same or different, but when the pressure resistance, the formability, etc. are taken into consideration, those having a circular outer periphery of the base material are preferably used. The

  Examples of such hollow porous substrates include melt-spun stretched porous hollow fiber membranes, hollow braids knitted with various fibers, and films formed on these substrates and membrane formation The thing etc. which immersed and apply | coated the auxiliary liquid are mentioned.

  Although the outer diameter of a hollow porous base material is not specifically limited, The thing of about 0.3 mm-5 mm is used suitably, for example. Since the outer shape fluctuation of the hollow porous substrate particularly affects the quality such as spinning stability and film thickness, it is preferable to use one having as little fluctuation as possible. For example, when the appearance of the hollow porous substrate is circular and the outer diameter is about 0.3 mm to 5 mm, the fluctuation range of the outer diameter may be ± 0.3 mm or less.

  On the other hand, the membrane-forming stock solution is a solution in which a film-forming resin capable of forming a porous membrane is dissolved alone or in a solvent by a wet or dry-wet spinning method, or an additive for controlling phase separation in this solution. The raw material is not particularly limited as long as spinning is possible.

(First embodiment)
First, the hollow fiber membrane composite nozzle according to the first embodiment of the present invention will be described. Here, (a) of FIG. 1 is a schematic cross-sectional view schematically showing a cross section of the hollow fiber membrane composite nozzle according to the first embodiment, and (b) is a cross-sectional view taken along II shown in (a). It is arrow sectional drawing along the line.

  The hollow fiber membrane composite nozzle 1 shown in FIG. 1 includes a first component 11 and a second component 12 provided adjacent to the first component 11. The first component part 11 has a substantially disc-shaped main body part 13 and a protruding tubular part 14 protruding from the main body part 13 toward the second component part 12 side, and the cross-sectional shape thereof is substantially T-shaped. Configured.

A first hollow portion 15 is formed in the central portion of the main body portion 13 and the protruding tubular portion 14 of the first component portion 11, and the first hollow portion 15 is a hollow porous substrate in the hollow fiber membrane composite nozzle 1. This is a travel path on which the material 2 travels. In this 1st Embodiment, the cross-sectional area of the 1st hollow part 15 is set larger than the cross-sectional area of the hollow porous base material 2 drive | worked there. Thereby, when the hollow porous substrate 2 is caused to travel to the first hollow portion 15, a predetermined size is provided between the inner wall surface of the first hollow portion 15 and the outer peripheral surface of the hollow porous substrate 2. A gap is formed along the longitudinal direction. This gap can be used as a part of the gas communication path 16 described in detail below. In this case, the inner diameter of the first hollow portion 15 is preferably set to more than 1.25 times the outer diameter of the hollow porous substrate 2, it is more preferable to set the particular 1.25 to 3 times .

  In addition to the first hollow portion 15, the first component portion 11 has a through hole 17 penetrating from the upper surface to the lower surface, and extends inward from the through hole 17 on the lower surface of the first component portion 11. And a first groove portion 18 formed in an annular shape around the portion 14.

  Further, the first component portion 11 has a second groove portion 19 formed on the upper surface thereof, extending from the outer peripheral surface toward the first hollow portion and formed in an annular shape around the first hollow portion 15. The second groove portion 19 becomes a part of the gas communication passage 16 when the introduction plate 3 described below is provided adjacent to the upper portion of the hollow fiber membrane composite nozzle 1. Further, the discharge side opening end (that is, the outer peripheral surface side end of the second groove portion 19) of the gas communication path 16 formed when the introduction plate 3 is installed becomes a connection port 20, and the connection port 20 includes, for example, the atmosphere A venting source (not shown) such as a release unit or an air pump is connected. The atmosphere release unit communicates the connection port with the external atmosphere so that gas can enter and exit between the connection port and the external atmosphere.

  The second groove portion 19 may have any shape and size as long as gas can be discharged. Further, the gas may be discharged in any direction. For example, the gas may be discharged in the discharge direction of the raw material, the upstream direction of travel of the hollow porous base material, or the orthogonal direction. Further, the number of connection ports 20 formed on the outer peripheral surface of the hollow fiber membrane composite nozzle 1 is not particularly limited, and may be one or plural.

  The second component 12 is a substantially disk-shaped member located on the lower surface side of the first component 11, and a second hollow portion into which the protruding tubular portion 14 of the first component 11 can be inserted at the center. Is formed. The inner diameter of the second hollow portion is formed larger than the outer diameter of the protruding tubular portion 14 of the first component, and when the protruding tubular portion 14 is inserted into the second hollow portion, A predetermined interval is obtained between the inner peripheral surface and the outer peripheral surface of the protruding tubular portion 14.

  The first component 11 and the second component 12 are integrated by inserting the protruding tubular portion 14 of the first component 11 into the second hollow portion of the second component 12 and concentrically overlapping each other. Thus, the hollow fiber membrane composite nozzle 1 is configured. In this case, the hollow fiber membrane composite nozzle 1 is formed between the through hole 17 formed in the first component 11, the first groove 18, the outer peripheral surface of the projecting tubular portion 14, and the inner peripheral surface of the second component. The film forming raw material flow passage 22 is formed by the predetermined interval.

  Further, in this hollow fiber membrane composite nozzle 1, the opening on the lower surface side of the membrane-forming stock solution passage 22 forms an annular membrane-forming stock solution discharge port 6 for discharging the membrane-forming stock solution. The base material discharge port 7 of the hollow porous substrate formed by the lower surface side opening of the first hollow portion 15 is located inside the portion surrounded by the inner closed line segment constituting the film forming stock solution discharge port 6. Is provided.

  Therefore, in the hollow fiber membrane composite nozzle 1, the membrane-forming stock solution discharge port 6 and the base material discharge port 7 are arranged apart from each other with the tip end portion of the protruding tubular portion 14 interposed therebetween. Moreover, the film-forming stock solution discharge port 6 is formed in a double line shape composed of an inner closed line segment and an outer closed line segment. An annular structure is formed by the component 12.

  When the first and second components 11 and 12 are configured to be disassembled, the nozzle is easily processed and cleaned after use, but there is a high risk of deforming the first component 11 during handling. This is one factor that causes a decrease in the service life. For this reason, it is preferable to integrate the first and second constituent parts 11 and 12 so as not to be disassembled, for example, at the stage of nozzle processing. Risk can be avoided.

  In order to integrally form the portions constituting the annular structure of the hollow fiber membrane composite nozzle 1, for example, a method of cutting the hollow fiber membrane composite nozzle 1 from a single member by various machining such as electric discharge machining is used. However, considering the ease of processing, etc., the first component 11 and the second component 12 are separately manufactured as shown in FIG. Are preferably integrated by assembling, various types of bonding such as press fitting, brazing, and diffusion bonding, and adhesion. In particular, when the first component portion 11 and the second component portion 12 are integrally formed, it is more preferable to use a processing method that does not require assembly processing.

  For example, when forming a cylindrical porous membrane having a uniform film thickness in the circumferential direction on the peripheral surface of the hollow porous substrate, both the inner and outer closed line segments in the membrane-forming stock solution discharge port 6 are both Circular and concentric are preferable. When either or both of the inner and outer closed line segments at the film-forming stock solution discharge port 6 have a shape such as an ellipse, or are eccentric, the film-forming stock solution discharge port 6 produces the film-forming stock solution. It is reflected in the discharge shape of the film stock solution as it is, and the film thickness tends to be non-uniform in the circumferential direction.

  Further, in the hollow fiber membrane composite nozzle 1, the length of the double-line parallel cylindrical portion extending in the depth direction from the membrane-forming stock solution discharge port 6 is used for discharging the membrane-forming stock solution 8 in a predetermined shape. In order to appropriately obtain a flow resistance for rectifying action and uniform discharge in the circumferential direction, the outermost discharge diameter of the film-forming stock solution 8 is set to do (mm), and the length of the cylindrical portion is set to Li (mm). In this case, the value of “Li / do” is preferably set to be 0.2 or more, and more preferably set to be 0.5 or more and 3.0 or less. Moreover, in order to discharge the film-forming stock solution 8 uniformly in the circumferential direction, for example, an annular slit may be provided upstream of the cylindrical portion.

  In the hollow fiber membrane composite nozzle 1 of the first embodiment, the inner lower end surface (that is, the lower end surface of the projecting tubular portion 14) and the outer lower end surface (that is, the first lower end surface) of the nozzle portion adjacent to the membrane-forming stock solution discharge port 6. And the lower end surface of the two constituent parts) are present on the same plane perpendicular to the discharge direction of the film forming solution.

  For example, when the inner and outer lower ends adjacent to the membrane-forming stock solution discharge port of the hollow fiber membrane composite nozzle do not exist on the same plane, when the membrane-forming stock solution is discharged from the membrane-forming stock solution outlet, One of the long wall surfaces comes into contact with each other to cause flow resistance, and on the other side (the shorter side), there is no constrained wall surface, and a free state occurs. Therefore, when the film-forming stock solution is discharged from the annular film-forming stock solution discharge port where the positions of the inner and outer lower end faces are different, the film-forming stock solution ensures the intended discharge linear velocity due to the difference in flow resistance between the inside and outside as described above. There is a problem that the film thickness is not uniform in both the circumferential direction and the longitudinal direction.

Further, in the hollow fiber membrane composite nozzle in which the inner lower end surface adjacent to the film forming stock solution discharge port is located inward of the nozzle with respect to the outer lower end surface, the film forming stock solution becomes a hollow porous substrate in the composite nozzle. Will join. At this time, since the shear to the membrane-forming solution due to the flow resistance difference between the middle air porous substrate and the annular nozzle wall is likely to occur, a stable film formation becomes difficult. In addition, since there is no one that regulates the travel position of the hollow porous substrate at the substrate discharge port of the nozzle, there is a possibility that the misalignment of the hollow porous substrate directly becomes a film thickness unevenness. In addition, when a hollow porous base material having low rigidity is used, the hollow porous base material may be deformed by the discharge pressure of the film-forming stock solution.

On the other hand, the inner lower end surface adjacent to the film forming raw solution discharge port protrudes, and when the flow resistance portion exists on the inner periphery of the film forming raw solution, that is, the lower end surface of the protruding tubular portion 14 protrudes from the lower surface of the second component 12. In the case where the membrane forming stock solution passes through the flow resistance portion, it contacts and combines with the hollow porous base material, but the membrane forming stock solution is retained by the flow resistance due to the wall surface of the projecting tubular portion 14 protruding, and the outer discharge surface. Although there is a possibility of growing in the direction, there is a problem that stable film formation may be difficult although it is not affected by the misalignment of the hollow porous substrate.

  In particular, when the inner protruding tubular portion protrudes long, the outer peripheral side of the film-forming stock solution has no constrained portion, so that the film-forming stock solution is discharged from the outer discharge port (first surface) by the flow resistance with the inner wall surface. 2), the film thickness tends to be non-uniform in the circumferential direction and the longitudinal direction.

  Accordingly, as in the first embodiment, if the inner and outer lower end surfaces adjacent to the film-forming stock solution discharge port 6 are on the same plane perpendicular to the film-forming solution discharge direction, When the stock solution 8 is discharged, the film-forming stock solution 8 can be simultaneously released from the internal and external flow resistance portions constituting the flow path of the film-forming stock solution 8 and can be uniformly discharged at a predetermined discharge linear velocity. Moreover, even if the hollow porous base material 2 having low rigidity is used, the hollow porous base material 2 and the film-forming stock solution 8 are discharged from the discharge ports 7 and 6 and then contacted by passing through a predetermined space. In order to make it composite, it can also prevent that the hollow porous base material 2 deform | transforms with the discharge pressure of the film-forming stock solution 8.

  In the present invention, the inner and outer lower end surfaces adjacent to the film-forming stock solution discharge port 6 are in the range of +0.5 mm to -5 mm, assuming that the protruding side of the inner lower end surface is the + side with respect to the outer lower end surface. More preferably, it is in the range of +0.3 mm to -0.3 mm, and more preferably in the range of 0 mm to -0.1 mm.

  Further, in order to make the inner and outer lower end faces adjacent to the film-forming stock solution discharge port 6 the same plane, for example, after the first and second components 11 and 12 are integrated, It is preferable to polish the discharge surface, that is, the inner and outer lower end surfaces at the same time.

  Furthermore, as shown in FIG. 1, the hollow fiber membrane composite nozzle 1 of the first embodiment has an introduction plate 3 on the top thereof. The introduction plate 3 positions the traveling position of the hollow porous substrate 2 that travels the traveling path 15 of the hollow fiber membrane composite nozzle 1 at a predetermined position.

  That is, in the hollow fiber membrane composite nozzle 1 of the first embodiment, as described above, the cross-sectional area of the travel path (first hollow portion) 15 is made larger than the cross-sectional area of the hollow porous base material 2, so that the gas Since the communication passage 16 is formed, the hollow fiber membrane composite nozzle 1 is not provided with means for regulating the traveling position of the hollow porous substrate 2. For this reason, when manufacturing a composite hollow fiber membrane, the running position of the hollow porous base material 2 may change, resulting in misalignment. For example, a membrane-forming auxiliary liquid as described below is a hollow porous material. In the case of being applied to the surface of the substrate, liquid dripping occurs due to the wall surface contact of the traveling path 15, and the stability of the film formation may be impaired.

  Therefore, in the first embodiment, the introduction plate 3 is disposed immediately above the hollow fiber membrane composite nozzle 1. Thus, even when a gap is provided between the inner wall surface of the traveling path 15 of the hollow fiber membrane composite nozzle 1 and the outer peripheral surface of the hollow porous base material 2, the hollow porous base material 2 is held at a predetermined position. Since it can be made to travel stably, stable film formation can be performed without causing misalignment.

  For example, as shown in FIG. 1, the introduction plate 3 is inserted into the center of the substantially disk-shaped member so that the hollow porous substrate 2 can be inserted and the substrate can be properly positioned. A hole 21 is provided. However, the present invention is not limited to this, and may have any shape as long as the travel position of the hollow porous substrate can be regulated, and may be appropriately selected according to necessary shaping conditions. Further, the introduction plate 3 has a low running resistance of the hollow porous substrate 2, and particularly when the film forming auxiliary liquid is applied to the hollow porous substrate 2, the film forming auxiliary liquid is ironed from the hollow porous substrate 2. It is preferable to have a shape that cannot be taken.

  Further, the base material insertion hole 21 of the introduction plate 3 has a base material insertion hole 21 when the appearance of the hollow porous base material 2 is, for example, a circle of about several millimeters in relation to the hollow porous base material 2 to be inserted. It is preferable to set the clearance between the inner peripheral surface of the minimum inner diameter portion and the outer peripheral surface of the hollow porous substrate 2 to be about 0.05 mm or more and 1 mm or less. By setting the clearance between the base material insertion hole 21 and the hollow porous base material 2 to a value within the above range, the hollow porous base material 2 is stable at a predetermined position without receiving a large running resistance. You can travel.

  Further, the base material introduction port in the introduction plate 3 may have any shape as long as it does not interfere with the travel of the hollow porous base material 2. For example, the end surface of the introduction port is subjected to R processing or chamfering processing. It is also possible to perform taper processing such that the inner diameter gradually decreases in the traveling direction, or to perform processing combining these. The introduction plate 3 is formed with a flow hole 23, and when the introduction plate 3 is stacked on the upper surface of the hollow fiber membrane composite nozzle 1, the through hole 17 and the first groove 18 of the first component 11. Together with this, the film forming raw material flow passage 22 is formed.

  For example, in order to stabilize the traveling position of the hollow porous substrate 2, the introduction plate 3 forms a pipe-like protruding portion that protrudes from the center of the substantially disk-shaped member to the first component 11 side with a predetermined length. However, for example, when it is more advantageous not to provide such a pipe-like protrusion when considering workability and operability, the base material insertion hole 21 is formed in a substantially disk-shaped member. A simply processed introduction plate 3 is preferably used.

  Furthermore, the lead-out side end portion of the base material insertion hole 21 in the introduction plate 3 is releasable from the film formation auxiliary liquid from the introduction plate 3 when, for example, the film formation auxiliary liquid is applied to the hollow porous base material 2. In view of the above, it is preferable to have a structure that does not drop the edge as much as possible. In addition, the diameter of the outlet side end portion of the base material insertion hole 21 in the introduction plate 3 is smaller than the traveling path of the hollow fiber membrane composite nozzle 1. Therefore, for example, when the film formation auxiliary liquid is a low-viscosity liquid, an annular relief groove process 24 (see FIG. 5) is formed on the lower surface of the introduction plate 3 in order to prevent the film formation auxiliary liquid from growing on the lower surface of the introduction plate 3. 4).

  In this relief groove processing, it is preferable to provide a recess so as not to leave as much as possible the lower surface near the outlet of the base material insertion hole 21. For example, when the diameter of the outlet is about several millimeters, the recess formed on the lower surface It is preferable that relief groove processing is performed so that the length in the radial direction is about 0.2 mm to 1 mm.

  When producing a composite hollow fiber membrane using the hollow fiber membrane composite nozzle 1 according to the first embodiment as described above, first, a hollow is formed in the traveling path 15 of the hollow fiber membrane composite nozzle 1 via the introduction plate 3. The porous substrate 2 is inserted and run. As a result, the travel position of the hollow porous substrate 2 is determined by the introduction plate 3, and the hollow porous substrate 2 is traveled at a substantially central position of the travel path 15 of the hollow fiber membrane composite nozzle 1. The substrate 2 can be continuously discharged from the substrate discharge port 7. At this time, a predetermined gap is formed along the traveling direction of the hollow porous substrate 2 between the inner wall surface of the traveling path 15 in the hollow fiber membrane composite nozzle 1 and the outer peripheral surface of the hollow porous substrate 2. The gas communication passage 16 is formed.

  In addition, the hollow porous base material 2 is discharged from the base material discharge port 7 of the hollow fiber membrane composite nozzle 1, and a film forming raw solution is introduced into the film forming raw material flow passage 22 formed in the introduction plate 3 and the hollow fiber membrane composite nozzle 1. 8 is supplied, and the film-forming stock solution 8 is discharged from the film-forming stock solution discharge port 6 in a cylindrical shape so as to surround the entire circumference of the hollow porous substrate 2. At this time, since the lower end surface adjacent to the inner and outer sides exists on the same plane as described above, the film-forming stock solution discharge port 6 simultaneously releases the film-forming stock solution 8 from the inner and outer flow resistance portions, It is possible to discharge stably and uniformly at a predetermined discharge linear velocity in the circumferential direction. Thereby, the membrane forming undiluted solution 8 has high followability to the hollow porous substrate 2 and can stably form the porous membrane on the hollow porous substrate 2.

  Further, the discharge linear velocity Vq (m / min) when the membrane-forming stock solution 8 is discharged from the hollow fiber membrane composite nozzle 1 is V / m when the traveling speed of the hollow porous substrate 2 is V (m / min). It is preferable to control each speed so that Vq ≧ 1, and it is more preferable to control the value of V / Vq to about 1 or more and 10 or less, although it depends on the spinnability of the film-forming stock solution 8. When the value of V / Vq is less than 1, the discharge linear velocity of the membrane-forming stock solution 8 exceeds the traveling speed of the hollow porous substrate 2, so that the membrane-forming stock solution 8 is combined with the hollow porous substrate 2. In addition, there is a risk that spots are likely to occur in the film-forming stock solution.

  Further, by discharging the hollow porous base material 2 and the membrane-forming stock solution 8 from the discharge ports 7 and 6 as described above, the discharged hollow porous base material 2, the membrane-forming stock solution 8, and the hollow porous material are discharged. A space 25 in which a gas intervenes is formed between the base material and the confluence of the film forming stock solution. The space 25 communicates with a connection port 20 connected to an air extraction source or the like via the gas communication path 16. Then, the hollow porous base material 2 and the film-forming stock solution 8 discharged from the discharge ports 7 and 6 are merged after passing through the space 25 formed between them, thereby bringing them into contact with each other. Combine and integrate.

  At this time, the space 25 formed between the hollow porous base material 2 and the film-forming stock solution 8 is connected to the atmospheric release portion by connecting the connection port 20 to the atmospheric release portion, whereby the pressure difference between the space 25 and the outside is obtained. The state of the space 25 is maintained in a natural form. The volume and shape of the space 25 are variable depending on the arrangement of the film-forming stock solution discharge port 6, discharge conditions, and the like, but by connecting the connection port 20 to, for example, a pressure-increasing / decreasing device, forcing gas in and out. The volume can be maintained arbitrarily and at a constant size. The space 25 has a substantially conical shape downward in the vertical direction, and the hollow porous base material 2 and the film forming stock solution 8 can be joined at a predetermined point. In addition, the position where the hollow porous base material 2 and the film-forming stock solution 8 merge is not particularly limited, and can be appropriately selected according to the film-forming conditions.

  The following effects can be acquired by making the membrane-forming stock solution 8 merge with the hollow porous substrate 2 as described above. That is, for example, when the film-forming stock solution discharge port 6 is formed on the same plane, if the space 25 communicating with the external atmosphere is not formed between the hollow porous base material 2 and the film-forming stock solution 8, When the gas discharged along with the hollow porous base material 2 is difficult to move into the hollow porous base material 2, the gas is generated between the two when the hollow porous base material 2 and the film forming stock solution 8 are merged. It will be bitten. In particular, in the case where the film forming auxiliary liquid is applied to the hollow porous substrate 2, the accompanying gas becomes remarkable, and a film defect portion is generated depending on the amount of the gas.

  Therefore, as in the hollow fiber membrane composite nozzle 1 of the first embodiment, the space 25 formed between the hollow porous substrate 2 discharged from the discharge ports 7 and 6 and the membrane forming stock solution 8 is gas. By being connected to the atmosphere release part or the ventilation source via the communication path 16, the accompanying and discharged gas together with the hollow porous base material 2 moves to the space 25, and then is removed by the ventilation source or the like. It can be discharged to the outside. Therefore, it is possible to effectively prevent gas from being trapped between the hollow porous base material 2 and the film-forming stock solution 8, and the presence of gas between the hollow porous base material 2 and the film-forming stock solution 8, It is possible to prevent the growth of gas and to stably perform composite spinning of the film forming stock solution 8 for a long time.

Next, the hollow porous base material 2 combined with the film-forming stock solution 8 as described above is dipped and coagulated in a coagulating liquid after traveling in air for a predetermined distance. Later, for example, by going through the steps such as washing in hot water, it is possible to obtain a composite hollow fiber membrane.

  The composite hollow fiber membrane produced in this way can suppress gas entrapment when the hollow porous base material 2 and the membrane-forming stock solution 8 are merged as described above, resulting in the entrainment of gas. Thus, a porous membrane having no abnormal outer diameter and no membrane defects due to local thinning is formed into a composite hollow fiber membrane having a stable membrane quality in which the porous membrane is uniformly formed in the circumferential direction and the longitudinal direction.

  In the first embodiment, when the raw film forming solution 8 is composite-spun on the hollow porous substrate 2, for example, the hollow porous substrate 2 is formed in advance and then formed again. In the case of performing multi-layered structure spinning or when the pretreatment of the hollow porous base material 2 is performed in advance, a film forming auxiliary liquid (for example, an internal coagulation liquid such as glycerin) is supplied to the hollow porous base material 2 There is a case.

  In such a case, for example, as shown in FIGS. 4 to 6, the merging plate 4 for supplying the membrane formation auxiliary liquid is disposed on the upper part of the hollow fiber membrane composite nozzle 1. The junction plate 4 is provided with an inlet 26 for introducing the hollow porous substrate 2, an auxiliary liquid supply port 27 for supplying a film forming auxiliary liquid to the peripheral surface of the hollow porous substrate 2, and a film forming auxiliary liquid. Any form may be used as long as it has the outlet port 28 for feeding out the hollow porous substrate, and it is particularly preferable that the hollow porous substrate 2 has a form that does not hinder the traveling of the hollow porous substrate 2.

  Moreover, if such a confluence | merging plate 4 is arrange | positioned upstream of the hollow fiber membrane spinning nozzle 1, the arrangement position will not be specifically limited. For example, the junction plate 4 can be disposed immediately above the hollow fiber membrane spinning nozzle 1 as shown in FIG. In this case, in order to stabilize the traveling position of the hollow porous substrate 2, the merging plate 4 can adopt a configuration that also functions as the introduction plate 3.

  Further, as shown in FIG. 5, for example, the confluence plate 4 can be disposed on the hollow fiber membrane spinning nozzle 1 via one or a plurality of intermediate plates 29 or the like. In this case, the intermediate plate 29 can be provided with an exhaust part 31 for exhausting gas, and the gas accompanying the hollow porous substrate 2 can be discharged to the outside.

  Furthermore, as shown in FIG. 6, the joining plate 4 is completely separated from the hollow fiber membrane spinning nozzle 1 through a plurality of intermediate plates 29 and the like between the hollow fiber membrane spinning nozzle 1 and the joining plate 4. It is also possible to arrange.

  In the merging plate 4, for example, the end face of the introduction port 26 into which the hollow porous base material 2 is introduced is subjected to R machining or chamfering, or taper machining such that the inner diameter becomes smaller in the traveling direction, It is possible to perform processing combining these.

  The supply port 27 for the film formation auxiliary liquid may have any shape as long as the film formation auxiliary liquid can be supplied to the outer periphery of the hollow porous base material 2. It is preferable that the material can be supplied from the entire circumferential direction of the base material 2. For example, if the membrane formation auxiliary liquid supply port 27 is opened in a circular slit shape surrounding the hollow porous substrate 2, the film formation auxiliary liquid is supplied from the slit shape supply port to the peripheral surface of the hollow porous substrate 2. Can be supplied uniformly.

  Furthermore, the shape, length, etc. of the confluence | merging part 30 which joins the hollow porous base material 2 and film | membrane formation auxiliary | assistant liquid in the confluence | merging plate 4 are the quantity, property, role of the hollow porous base material 2 and film | membrane formation auxiliary | assistant liquid. Depending on, it may be selected appropriately. For example, if the merging part 30 is provided on the upstream side and the downstream side of the film forming auxiliary liquid supply port 27, the film forming auxiliary liquid is applied to the outer peripheral surface of the hollow porous substrate 2 at the merging part 30 and applied. can do. The junction 30 is basically divided on the upstream side and the downstream side of the supply port 27, and the shapes of the upstream part and the downstream part may be the same or different, and between the upstream part and the downstream part. The inner diameter and length may be the same or different, and can be selected as appropriate.

  In the case where the inner wall surface of the merging portion 30 is contaminated by the travel of the hollow porous substrate 2, for example, the auxiliary liquid supply port 27 is supplied by excessively supplying the film formation auxiliary liquid from the auxiliary liquid supply port 27, for example. It is possible to clean the merging portion 30 and the inner wall surface upstream of the merging portion 30 by overflowing the film formation auxiliary liquid from the inlet 26 provided upstream of the merging portion. In this case, it is preferable to provide an auxiliary liquid discharge part 32 for discharging the overflowed film formation auxiliary liquid.

  Furthermore, the outlet 28 through which the hollow porous base material 2 to which the film forming auxiliary liquid has been applied passing through the merging portion 30 is delivered opens at a right angle to the traveling direction of the merging portion 30. In consideration of the releasability of the film forming auxiliary liquid from the confluence plate 4, it is preferable that the edge of the lower surface side end portion of the confluence plate 4 constituting the outlet 28 not be dropped as much as possible. In the case of a low-viscosity liquid, it is more preferable that an annular relief groove process 24 is applied to suppress the growth on the discharge surface.

  The escape groove machining 24 is preferably provided with a recess so as not to leave the discharge surface in the vicinity of the merge plate outlet 28 as much as possible, like the discharge port in the introduction plate 3. For example, the diameter of the outlet of the merge plate 4 is about several millimeters. In such a case, it is preferable that relief groove processing 24 is performed so that the length of the concave portion in the radial direction of the lead-out surface is about 0.2 mm to 1 mm.

(Second Embodiment)
Next, a hollow fiber membrane composite nozzle according to a second embodiment of the present invention will be described. Here, (a) of FIG. 2 is a schematic cross-sectional view schematically showing a cross section of the hollow fiber membrane composite nozzle according to the second embodiment, and (b) is II-II shown in (a). It is arrow sectional drawing along the line. In the description of the second embodiment and the third embodiment to be described next, members having substantially the same configuration as the members described in the first embodiment are denoted by the same reference numerals. Therefore, the description thereof is omitted.

  The hollow fiber membrane composite nozzle 41 shown in FIG. 2 includes a first component 11 ′ and a second component 12 ′ that is assembled adjacent to the first component. The first component 11 ′ has a substantially disc-shaped main body 13 and a projecting tubular portion 14 protruding toward the second component 12 ′ at the center of the main body 13, The cross-sectional shape is generally T-shaped.

  In the second embodiment, a first hollow portion 15 'serving as a travel path on which the hollow porous base material 2 travels is formed at the center of the first component 11'. However, the first hollow portion 15 ′ is not used as the gas communication path 16 unlike the hollow fiber membrane composite nozzle 1 of the first embodiment. In addition, since the first hollow portion 15 ′ defines the travel position of the hollow porous substrate 2, the inner diameter of the first hollow portion 15 ′ is the hollow porous substrate 2 that travels the first hollow portion 15 ′. The outer diameter is preferably set to about 1.25 times or less. Moreover, it is preferable to set the clearance between the inner peripheral surface of the first hollow portion 15 ′ and the outer peripheral surface of the hollow porous substrate 2 to be about 0.05 mm or more and 1 mm or less.

  In addition, the base insertion port of the first hollow portion 15 ′ is, for example, subjected to R processing or chamfering processing on the end surface of the introduction port, or in order to stably insert the hollow porous base material into the first hollow portion. It is also possible to perform a taper process in which the inner diameter gradually decreases in the direction, or a process in which these are combined.

  The first component portion 11 ′ and the second component portion 12 ′ have various types such as press-fitting, brazing, and diffusion bonding at the stage of nozzle processing in order to prevent displacement during assembly and deformation of the nozzle. It is preferable that the hollow fiber membrane composite nozzle 41 is configured by being integrated so as not to be disassembled by bonding or adhesion. Further, in the hollow fiber membrane composite nozzle 41 configured integrally as described above, the inner lower end surface and the outer lower end surface adjacent to the annular film forming stock solution discharge port 6 are perpendicular to the discharge direction of the film forming stock solution 8. It exists on the same plane. Further, four elongated gas communication passages 42 and the first hollow portion 15 ′ are formed between the annular film-forming stock solution discharge port 6 and the base material discharge port 7 formed so as to be separated from the inside thereof. The four gas communication paths 42 communicate with the connection port 20 and are formed in parallel with a predetermined length.

  By producing a composite hollow fiber membrane using the hollow fiber membrane composite nozzle 41 of the second embodiment as described above, the same effect as in the first embodiment can be obtained. That is, the hollow porous substrate 2 is caused to travel along the traveling path (first hollow portion) 15 ′ of the hollow fiber membrane composite nozzle 41, and the hollow porous substrate 2 is continuously discharged from the substrate discharge port 7. At the same time, the film-forming stock solution 8 is supplied to the film-forming stock solution flow path 22 of the hollow fiber membrane composite nozzle 41 so that the film-forming stock solution is surrounded by the film-forming stock solution discharge port 6 around the entire circumference of the hollow porous substrate 2. A cylinder is discharged at a predetermined discharge linear velocity.

  Further, by discharging the hollow porous substrate 2 and the membrane forming raw solution 8 from the respective discharge ports 7 and 6 in this way, the discharged hollow porous substrate 2, the film forming raw solution 8 and the hollow porous substrate 2 are discharged. In addition, a space 25 in which gas is present is formed between the merging point of the film-forming stock solution 8. The space 25 communicates with the connection port 20 via four gas communication passages 42 formed between the film forming raw solution discharge port 6 and the substrate discharge port 7. Then, the hollow porous base material 2 and the film-forming stock solution 8 discharged from the discharge ports 7 and 6 are merged and integrated at a predetermined point after passing through the space 25.

  As a result, the gas discharged along with the hollow porous base material 2 moves to the space 25 and then is discharged to the outside through the gas communication path 42 by the atmosphere release unit or the air extraction source connected to the connection port 20. can do. For this reason, gas entrainment between the hollow porous substrate 2 and the film-forming stock solution 8 is suppressed, and gas interposition and gas growth occur between the hollow porous substrate 2 and the film-forming stock solution 8. This makes it possible to perform stable spinning for a long time.

Next, the hollow porous base material 2 and the film-forming stock solution 8 integrated as described above are immersed in a coagulating liquid and solidified. Thereafter, a composite hollow fiber membrane can be obtained through a process such as washing in hot water.

  Since the composite hollow fiber membrane manufactured in this way can inhibit the biting of gas when contacting and combining the hollow porous base material and the membrane-forming stock solution as in the first embodiment, A composite hollow fiber membrane is obtained in which a porous membrane having a stable membrane quality in which no abnormal outer diameter portion or membrane defect portion due to local thinning has occurred is uniformly formed.

  In addition, the hollow fiber membrane composite nozzle 41 of the second embodiment is similar to the first embodiment in that the introduction plate 3 that defines the traveling position of the hollow porous substrate 2 on the upper portion thereof, the hollow porous substrate 2 and the like. It is also possible to dispose a merging plate 4 for applying a film forming auxiliary liquid.

  Although the hollow fiber membrane composite nozzle 41 of the second embodiment can position the traveling position of the hollow porous substrate 2 with the first hollow portion 15 ′ without providing the introduction plate 3, the hollow fiber membrane By further providing the introduction plate 3 upstream of the composite nozzle 41, the traveling position of the hollow porous substrate 2 can be further stabilized, and misalignment of the hollow porous substrate 2 can be reliably prevented.

  Further, by arranging the merging plate 4 upstream of the hollow fiber membrane composite nozzle 41, before the membrane-forming stock solution is combined with the hollow porous substrate 2, membrane formation assistance is provided on the peripheral surface of the hollow porous substrate 2. The liquid can be supplied uniformly. In addition, if the introduction plate 3 and / or the merging plate 4 are provided on the upper part of the hollow fiber membrane spinning nozzle 21, the arrangement position thereof is not particularly limited. For example, the introduction plate can be provided just above the hollow fiber membrane composite nozzle 41 or the intermediate plate 29 can be provided on the hollow fiber membrane composite nozzle 41 in the same manner as in the first embodiment.

(Third embodiment)
Next, a hollow fiber membrane composite nozzle according to a third embodiment of the present invention will be described. Here, (a) of FIG. 3 is a schematic cross-sectional view schematically showing a cross section of the hollow fiber membrane composite nozzle according to the third embodiment, and (b) is a III-III shown in (a). It is arrow sectional drawing along the line.

  The hollow fiber membrane composite nozzle 51 shown in Fig. 3 includes a first component 11 "and a second component 12" assembled adjacent to the first component 11 ". The constituent part 11 ″ is composed of a lower member 52 and an upper member 53, and the lower member 52 has a substantially disc-shaped main body part 54 and a protruding tubular part 55 protruding toward the second constituent part side. The cross-sectional shape is generally T-shaped. Further, a third hollow portion is formed at the center of the lower member 52, and a gas communication path 56 is provided on the upper surface.

  Further, the upper member 53 constituting the first component portion 11 ″ has a substantially disc-shaped main body portion 54 ′ and a protruding tubular portion 55 ′ protruding into the third hollow portion of the lower member 52, The cross-sectional shape is generally T-shaped, and a first hollow portion 15 ′ for running the hollow porous substrate 2 is formed at the center of the upper member 53.

By inserting the projecting tubular portion 55 ′ of the upper member 53 into the third hollow portion of the lower member 52 and arranging it concentrically, the first component 11 ″ is formed. An annular slit extending in a predetermined length in parallel with the first hollow portion 15 ′ is formed as a gas communication path 56 between the projecting tubular portion 55 ′ of the member 53.

Further, the projecting tubular portions 55 and 55 ′ of the first component 11 ″ are inserted into the second hollow portion of the second component 12 ″ and arranged concentrically to form the hollow fiber membrane composite nozzle 51. At this time, the membrane forming raw material flow passage 22 is formed in the hollow fiber membrane composite nozzle 51.

  In order to prevent the first component portion 11 ″ and the second component portion 12 ″ formed of the upper member 53 and the lower member 52 from being displaced at the time of assembling or the nozzle being deformed, It is preferable that they are integrated so that they cannot be disassembled by various types of bonding such as press fitting, brazing, and diffusion bonding, and adhesion.

  In the hollow fiber membrane composite nozzle 51 of the third embodiment configured integrally as described above, the inner lower end surface and the outer lower end surface adjacent to the annular film forming stock solution discharge port 6 have a discharge direction of the film forming stock solution 8. Exist on the same plane perpendicular to. In addition, an annular gas communication path 56 is formed in a predetermined length in parallel with the first hollow portion 15 ′ between the film-forming stock solution discharge port 6 and the base material discharge port 7 that is formed to be separated from the inside. The gas communication path 56 is formed and communicates with the connection port 20.

  Furthermore, in the present third embodiment, the inner diameter of the first hollow portion 15 ′ of the upper member 53 is equal to the outer diameter of the hollow porous substrate 2 in order to stabilize the traveling position of the hollow porous substrate 2. It is preferable to set it to about 25 times or less, and the clearance between the inner peripheral surface of the first hollow portion 15 ′ and the outer peripheral surface of the hollow porous substrate 2 is about 0.05 mm or more and 1 mm or less. It is preferable to set. Further, the base insertion port of the first hollow portion 15 ′ is subjected to R processing or chamfering, for example, on the end surface of the insertion port in order to stably insert the hollow porous base material 2 into the first hollow portion 15 ′. It is also possible to perform taper processing such that the inner diameter gradually decreases in the traveling direction, or to perform processing combining these.

  By producing a composite hollow fiber membrane using the hollow fiber membrane composite nozzle 51 of the third embodiment as described above, the same effect as in the first and second embodiments can be obtained. That is, the hollow porous base material 2 is continuously discharged from the base material discharge port 7 of the hollow fiber membrane composite nozzle 51, and the film forming stock solution 8 is discharged from the film forming stock solution discharge port 6 all around the hollow porous base material 2. The hollow porous base material 2 and the film-forming stock solution 8 are joined at a predetermined point by being discharged in a cylindrical shape at a predetermined discharge linear velocity so as to surround.

  At this time, a space 25 in which gas is interposed is formed between the hollow porous substrate 2, the membrane forming raw solution 8, and the confluence of the hollow porous substrate 2 and the film forming raw solution 8 discharged from each discharge port. The Since this space 25 communicates with the connection port 20 via the gas discharge portion 56, the gas discharged along with the hollow porous base material 2 passes through the gas discharge portion 56 from the space 25 and is released to the atmosphere. It can be discharged to the outside by a part or a ventilation source. Therefore, during the composite spinning, gas entrainment between the hollow porous base material 2 and the film-forming stock solution 8 is suppressed, and there is no gas between the hollow porous base material 2 and the film-forming stock solution 8, Prevents the growth and enables stable spinning for a long time.

  Therefore, the composite hollow fiber membrane manufactured in this way has a stable membrane quality in which no abnormal outer diameter portion or membrane defect portion due to local thinning occurs as in the first and second embodiments. It becomes a composite hollow fiber membrane in which the porous membrane is uniformly formed.

  In addition, also in the hollow fiber membrane composite nozzle 51 of the third embodiment, the introduction plate 3 that determines the traveling position of the hollow porous substrate 2 upstream, and the membrane formation auxiliary liquid are applied to the hollow porous substrate 3. The confluence plate 4 can be disposed in the same manner as in the first embodiment.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings by way of examples and comparative examples. In Examples and Comparative Examples, film thickness unevenness of the porous film formed on the hollow porous substrate was measured using the following method.

(Method for measuring film thickness of porous membrane)
A sample for measuring the film thickness was cut to about 100 mm at an arbitrary place, 6 pieces were bundled in a row, one end was fixed with an adhesive tape, and the other end was cut with a single-blade razor to make about 60 mm. Two samples were prepared for one sample. Two double-sided tapes having a width of 5 mm were applied in parallel at intervals of 40 mm on a polyethylene sample bag, and the sample bundled thereon was fixed. Further, both ends of the sample bundle fixed on the double-sided tape were fixed on a polyethylene sample bag with a gum tape of 25 mm on the side bundled with the adhesive tape and 5 mm on the other end.

  Next, a polyurethane resin for fixing the sample was prepared. As the polyurethane resin, Coronate 4403 and Nippon Run 4223 of Nippon Polyurethane Industry Co., Ltd. were used, and Coronate / Nippon Run was prepared at 52/42 (mass%). Using the prepared polyurethane resin, it was covered with a 5 mm wide gum tape so as to cover the foot, and pushed in with a spatula so that the potting resin could enter the hollow part. Further, the entire sample bundle was covered with the polyurethane resin so that the polyurethane resin was spread between the membranes and the bubbles generated in the polyurethane resin were removed. In order to sufficiently solidify the polyurethane resin, it was left for 12 hours or more.

  After the polyurethane resin was cured, the sample was removed from the polyethylene sample bag. The 5 mm wide gum tape portion used for fixing the sample was cut with scissors, and then three thin pieces having a thickness (longitudinal direction of the membrane) of about 0.5 mm were sampled using a single blade razor. Similarly, three slices were sampled from another prepared sample bundle.

  The sampled three slices were placed on a glass slide for observation with an optical microscope, and the slice sliced most cleanly among the three slices was selected. Similarly, one slice was selected from the three slices of the other sample bundle.

  Next, the cross section of the sampled hollow fiber membrane was observed at a magnification of 100 times with an objective lens using a projector (PROFILE PROJECTOR V-12 manufactured by Nikon). The film thickness was read by combining marks (lines) at the positions of the outer and inner surfaces of the second layer at the 3 o'clock position on the cross section of the observed hollow fiber membrane. Similarly, the film thickness was read in the order of 9 o'clock, 12 o'clock, and 6 o'clock. The film thickness was measured by reading six cross sections from one thin piece and four cross sections from the other thin piece, one sample piece selected from each of two sample bundles.

  In the film thicknesses measured at four locations per cross section in a total of 10 (n = 10 locations) measured by the above method, Tmax: maximum film thickness (μm), Tmin: minimum film thickness (μm), The average value of film thickness unevenness was obtained by the calculation formula.

(Examples 1-7 and Comparative Examples 1-3)
The hollow fiber membrane composite nozzle used in this example has the structure shown in FIG. 7, and an introduction plate 3 upstream of the hollow fiber membrane composite nozzle 1 according to the first embodiment shown in FIG. An intermediate plate 29 having an exhaust part 31 and a junction plate 4 are disposed. Table 1 shows the results of measuring the dimensions of each hollow fiber membrane composite nozzle used in Examples 1 to 7 and Comparative Examples 1 to 3, and the average film thickness of the porous membrane when the hollow fiber membrane was produced. .

  In the present Examples and Comparative Examples, in producing a composite hollow fiber membrane, as a membrane forming stock solution, polyvinylidene fluoride A (manufactured by Atofina Japan, trade name Kyner 301F), polyvinylidene fluoride B (manufactured by Atofina Japan, product) Name Kynar 9000HD), polyvinyl pyrrolidone (trade name K-90, manufactured by ISP), and N, N-dimethylacetamide were used to prepare the compositions shown in Table 2 below.

  As the hollow porous base material, the above-mentioned film-forming solution is applied to a polyester multifilament single woven hollow braid (multifilament; total decitex 830/96 filament, 16 beats), and a functional layer obtained by phase separation by dry and wet spinning What was formed was used. The outer diameter of this hollow porous substrate was approximately 2.4 to 2.5 mm.

  Further, as a coagulation bath, a solution of 5 parts by mass of N, N-dimethylacetamide and 95 parts by mass of water was used at 80 ° C.

  First, the hollow porous substrate 2 is inserted through the inlet 26 of the merging plate 4 and travels downward, and after merging with glycerin as an internal coagulating liquid as a film forming auxiliary liquid, the hollow porous substrate provided with glycerin The material 2 was discharged from the base material discharge port 7 of the hollow fiber membrane composite nozzle 1. At the same time, the membrane-forming stock solution 8 was discharged in a cylindrical shape from the membrane-forming stock solution discharge port 6 of the hollow fiber membrane composite nozzle 1. And the hollow porous base material 2 and the film-forming stock solution 8 which were discharged from each discharge port were merged and integrated after passing through the space 25. Subsequently, the integrated hollow porous substrate 2 and film forming stock solution 8 were run for a predetermined distance and then immersed in a coagulating liquid. Then, it pulled up from the coagulation liquid, took up with a spinning roll rotating at a constant speed so as to obtain a take-up speed of 6 m / min, and washed in hot water at 80 to 100 ° C. to produce a hollow fiber membrane.

When the hollow fiber membranes produced in Examples 1 to 7 were observed , no gas entrapment or growth was observed in any of the hollow fiber membranes. Moreover, as a result of calculating | requiring the average value of the said film thickness unevenness about the porous membrane in each hollow fiber membrane, it was in the range of 55-99 micrometers. On the other hand, in the hollow fiber membranes produced in Comparative Examples 1 and 2, although no gas entrapment was observed, the average values of the film thickness spots were 134 μm and 139 μm, respectively. It was confirmed that the film thickness of the formed porous membrane was non-uniform compared with the hollow fiber membranes of Examples 1-7. Further, in Comparative Example 3, when composite spinning of the membrane forming stock solution on the hollow porous substrate, gas was trapped between the hollow porous substrate and the membrane forming stock solution, so spinning was stopped. .

(A) is a schematic cross section which shows typically the cross section of the hollow fiber membrane composite nozzle which concerns on 1st Embodiment, (b) is an arrow view along the II line | wire shown to (a). It is sectional drawing. (A) is a schematic cross section which shows typically the cross section of the hollow fiber membrane composite nozzle which concerns on 2nd Embodiment, (b) is an arrow view along the II line | wire shown to (a). It is sectional drawing. (A) is a schematic cross section which shows typically the cross section of the hollow fiber membrane composite nozzle which concerns on 3rd Embodiment, (b) is an arrow view along the II line | wire shown to (a). It is sectional drawing. It is a schematic cross section which shows typically the cross section of the hollow fiber membrane composite nozzle which has arrange | positioned the confluence | combination plate which served as the introduction plate immediately above. It is a schematic cross section which shows typically the cross section of the hollow fiber membrane composite nozzle which has arrange | positioned the introduction plate, the intermediate | middle plate, and the confluence | merging plate in order. FIG. 2 is a schematic cross-sectional view schematically showing a cross section of a hollow fiber membrane composite nozzle in which an introduction plate, an intermediate plate, and a merging plate are arranged in order, and the intermediate plate is completely separated vertically. It is a schematic cross section which shows typically the cross section of the hollow fiber membrane composite nozzle used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane composite nozzle 2 Hollow porous base material 3 Introducing plate 4 Merge plate 6 Film-forming stock solution discharge port 7 Base material discharge port 8 Film-forming stock solution 11, 11 ′, 11 ″ First component part 12, 12 ′, 12 ″ Second component 13 Body portion 14 Projecting tubular portion 15, 15 ′ First hollow portion (travel path)
DESCRIPTION OF SYMBOLS 16 Gas communication path 17 Through-hole 18 1st groove part 19 2nd groove part 20 Connection port 21 Base material insertion hole 22 Film forming raw material flow path 23 Flow hole part 24 Escape groove process 25 Space 26 Inlet 27 Auxiliary liquid supply port 28 Outlet 29 Intermediate plate 30 Junction part 31 Exhaust part 32 Auxiliary liquid discharge part 41 Hollow fiber membrane composite nozzle 42 Gas communication passage 51 Hollow fiber membrane composite nozzle 52 Lower member 53 Upper member 54, 54 'Main body part 55, 55' Projecting tubular part 56 Gas communication path

Claims (6)

A hollow fiber membrane composite nozzle having an annular structure in which a hollow fiber membrane is obtained by composite spinning of a membrane-forming stock solution capable of forming a porous membrane on the peripheral surface of a hollow porous substrate,
An annular film-forming stock solution discharge port that discharges the film-forming stock solution and a substrate discharge port that is formed inside the film-forming stock solution discharge port and discharges the hollow porous substrate are arranged apart from each other,
An opening formed toward the space between the hollow porous base material and the membrane forming stock solution discharged from each outlet during composite spinning, and the confluence of the hollow porous base material and the membrane forming stock solution , A gas communication passage is formed in the nozzle portion between the film- forming stock solution discharge port and the base material discharge port, and communicates the opening and a connection port connected to the atmosphere release portion or an external venting source. ,
A hollow fiber membrane composite nozzle characterized by that.   2. The hollow fiber membrane composite nozzle according to claim 1, wherein an inner lower end surface and an outer lower end surface of a nozzle portion adjacent to the membrane-forming stock solution discharge port are on the same plane. The cross-sectional area of the travel path on which the hollow porous base material of the hollow fiber membrane composite nozzle travels is set larger than the cross-sectional area of the hollow porous base material,
The hollow fiber membrane composite nozzle according to claim 1 or 2, wherein the gas communication path is a gap between an inner wall surface of the travel path and an outer peripheral surface of the hollow porous substrate. On top of the hollow fiber membrane composite nozzle,
An inlet for introducing the hollow porous substrate;
An auxiliary liquid supply port for supplying a film forming auxiliary liquid to the peripheral surface of the hollow porous substrate;
A lead-out port for feeding out the hollow porous substrate to which the film forming auxiliary liquid is applied;
A hollow fiber membrane composite nozzle according to any one of claims 1 to 3 , comprising a confluence plate comprising: The hollow fiber membrane composite nozzle according to any one of claims 1 to 4 , further comprising an introduction plate for positioning a traveling position of the hollow porous base material at an upper portion of the hollow fiber membrane composite nozzle. . Using the hollow fiber membrane composite nozzle according to any one of claims 1 to 5 , the hollow porous substrate and the membrane forming stock solution are merged and integrated, and the integrated hollow porous substrate and membrane are integrated. A method for producing a composite hollow fiber membrane, wherein the stock solution is immersed and coagulated in a coagulation solution.

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