JP4894148B2 - Hollow fiber membrane manufacturing method and manufacturing apparatus thereof - Google Patents

Description

  The present invention relates to a method for producing a hollow fiber membrane by a dry and wet spinning method and a production apparatus therefor.

  In recent years, hollow fibers made of polymers have been developed and used for various purposes and applications. In particular, hollow fiber polymer membranes (hollow fiber membranes) are microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, gas separation membranes, nitrogen-rich membranes, oxygen-rich membranes, blood purification membranes, artificial kidneys, artificial lungs, etc. Has been put to practical use in various applications.

  Conventionally, as a method for producing a hollow fiber type separation membrane, a stock solution and a hollow forming material are simultaneously ejected using a double tube die, and after passing through a space of several centimeters to several tens of centimeters, they are guided to a coagulation bath. There is known a so-called dry-wet spinning method in which the traveling direction is changed upward by a liquid direction change guide, travels in the air again from the liquid surface of the coagulation bath, and proceeds to a water washing step and other steps through a rotating roller. In such a dry-wet spinning method, when a large number of hollow fiber membranes are to be spun, fusion occurs due to contact between the hollow fiber membranes in the space below the die, causing damage to the membrane surface or causing yarn breakage. Trouble occurs. Many proposals have been made so far to solve such troubles.

  For example, those in which a gas is circulated in the space under the base (for example, see Patent Document 1), those in which the space is surrounded in an unsealed state (for example, see Patent Document 2), and those in which the coagulation bath liquid flow is improved (For example, refer to Patent Document 3), a rectifying plate provided in a coagulation bath (for example, refer to Patent Document 4), and a damming plate provided on a coagulation bath inward direction changing roller (for example, Patent Document 5). (See, for example, Patent Document 6), and provided with a fixed coagulation bath in-direction conversion guide having a splitting projection (for example, Patent Document 7). (See, for example, Patent Document 8), and a liquid-in-direction conversion guide that can be raised and lowered (for example, Patent Document 9). ), Specify the direction change guide shape (See, for example, Patent Document 10) and the like have been proposed, but all of them are intended to reduce yarn disturbance by reducing the disturbance applied to the yarn and prevent the yarn from fusing in the dry part. is there.

However, when trying to improve the productivity by increasing the number of yarns, it is necessary to reduce the distance between the cap holes, that is, the pitch between the yarns, and the conventional technology prevents fusion due to contact between the hollow fiber membranes. It was difficult.
JP-A-5-44104 JP 2004-174408 A Japanese Patent Laid-Open No. 7-70813 Japanese Patent No. 2891115 JP-A-1-168909 Japanese Utility Model Publication No. 54-93514 Japanese Patent No. 4-3444 Japanese Patent Laid-Open No. 7-39731 Utility model 2529595 Japanese Examined Patent Publication No. 3-35402

  The object of the present invention is to prevent fusion due to contact between the hollow fiber membranes in the dry part in the production of a plurality of hollow fiber membranes by dry-wet spinning, and eliminate yarn breakage, flaws on the surface of the yarn, surface abnormalities, etc. An object of the present invention is to provide a method and apparatus for producing a hollow fiber membrane having excellent stability.

In order to achieve the above object, the present invention adopts the following configuration. That is,
(1) a plurality of hollow fiber membranes in a method of manufacturing the dry-wet spinning method, established a submerged redirecting guide into a coagulation bath, minute between the coagulating bath liquid surface and the liquid redirecting guide fiber A method for producing a hollow fiber membrane, characterized in that a guide is provided and a plurality of hollow fiber membranes are separated for each yarn by the fiber separation guide and run.

(2) After the hollow fiber membranes of the plurality of the minute fiber just below the mouthpiece by the minute fiber guide, the該分fiber guide moves in a coagulation bath liquid plane, be fixed to said (1), wherein The manufacturing method of the hollow fiber membrane of description.

( 3 ) In a dry / wet spinning apparatus for producing a plurality of hollow fiber membranes, a liquid direction change guide is installed in the coagulation bath, and further, the fiber is split between the coagulation bath liquid level and the liquid direction change guide. An apparatus for producing a hollow fiber membrane, comprising a guide.

( 4 ) The apparatus for producing a hollow fiber membrane according to ( 3 ), wherein the splitting guide includes a vertical guide and a horizontal guide.

( 5 ) The hollow fiber membrane manufacturing apparatus according to (4 ) , wherein the splitting guide is movably provided.

( 6 ) The apparatus for producing a hollow fiber membrane according to any one of ( 3 ) to ( 5 ), wherein a fixing means for fixing the vertical guide and the horizontal guide in a coagulation bath is provided.

  In the method and apparatus for producing a plurality of hollow fiber membranes by dry and wet spinning, the present invention prevents fusion due to contact between the hollow fiber membranes in the dry part, and breaks the yarn due to fusion. Further, it is possible to provide a method and apparatus for producing a hollow fiber membrane that eliminates scratches, surface abnormalities, and the like on the yarn surface and has excellent stability.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a side view showing an example of a dry / wet spinning apparatus for carrying out the present invention, and FIGS. 2 (A) to 2 (C) show that a hollow fiber membrane is split into yarns by a splitting guide. It is a schematic plan view showing an example of the state.

  In FIG. 1, the hollow fiber membrane 8 discharged from the base 10 enters the coagulation bath 11 through the dry portion, and travels in a state where the fiber is separated for each yarn by the separation guide 1 fixed to the fixing means 4. Then, the light is converged and redirected by the in-liquid direction changing guide 6 provided in the coagulation bath 11 and guided to a roll 7 provided above the coagulation bath in a yarn bundle state. The splitting guide 1 is composed of a warp guide and a horizontal guide, and each yarn is split for each yarn with a grid-like mesh formed by the vertical guide 2 and the horizontal guide 3 as shown in FIG. . In the manufacturing process of the hollow fiber membrane, each yarn runs alone until entering the coagulation bath, but the surface as the hollow fiber membrane has already been formed in the coagulation bath or the washing bath, and further in the dryer. Therefore, there are cases where a plurality of yarns are converged and run together, and the arrangement of the nozzle discharge holes is determined depending on the difference in the number of converging yarns.

  In the present invention, the warp guide is a guide for regulating and separating the yarn in a direction along the running direction (vertical direction) of the yarn whose direction is changed by the in-liquid direction changing guide 6 provided in the coagulation bath. The horizontal guide is a guide that regulates and separates the yarn in a direction (horizontal direction) orthogonal to or intersecting with the running direction of the yarn whose direction is changed by the submerged direction conversion guide 6 provided in the coagulation bath. . The hollow fiber membrane includes a hollow fiber membrane that is in an incompletely solidified state until the hollow fiber polymer fluid discharged from the die forms a porous layer in the flow-down process and solidifies in the coagulation bath.

  2 (A) and 2 (B) are plan view configuration examples of a fiber splitting guide when being focused on four yarns after the liquid direction change guide 6 provided in the coagulation bath 11. FIG. 2C is a plan view configuration example of a fiber splitting guide when it is converged to eight yarns after the in-liquid direction changing guide 6 provided in the coagulation bath.

  In FIG. 2 (A), the vertical guide 2 has a fork-like shape and comprises an edge 2a and a tooth 2b. On the other hand, the horizontal guide 3 has a comb-like shape and includes an edge 3a and a tooth 3b. It is the tooth portion 2b of the vertical guide 2 and the tooth portion 3b of the horizontal guide 3 that actually separates the yarn 8 for each yarn. The vertical guide 2 and the horizontal guide 3 in FIGS. 2 (B) and 2 (C) are 2 ′, 2 ″ and 3 ′, 3 ″, respectively, and the respective edges and teeth are 2a ′, 2b ′, 2a ″, 2b ″ and 3a ′, 3b ′, 3a ″, 3b ″.

  3 (A) and 3 (B) are schematic views for explaining the fiber-splitting operation in the running direction of the hollow fiber membrane by the vertical guide, FIG. 3 (A) is a plan view, and FIG. 3 (B) is a side view. It is. In FIG. 3 (A) and FIG. 3 (B), it has the edge part 2a of the length guide 2, and inserts the tooth | gear part 2b in the lengthwise direction of the thread | yarn 8 just under the nozzle | cap | die 10, and then length guide 2 Is lowered and fixed in the coagulation bath.

  4 (A) and 4 (B) are schematic views for explaining a fiber separation operation in a direction perpendicular to the traveling direction of the hollow fiber membrane 8 by a horizontal guide, FIG. 4 (A) is a plan view, and FIG. 4 (B). Is a side view. 4 (A) and 4 (B), the edge 3a of the horizontal guide 3 is held, the tooth 3b is lifted upward from below the base 10, and the edge is rotated just below the base while rotating the edge. Thus, the tooth portion 3b is inserted between the yarns 8 in the horizontal direction, and then the horizontal guide 3 is lowered and fixed in the coagulation bath. As shown in FIG. 4B, the number of yarns can be increased by arranging the caps 10 at intervals. It is possible to lengthen the length of the tooth portion 3b of the horizontal guide 3 so that the yarns corresponding to the two caps can be separated. When the number of the bases is small, the horizontal guide 3 is the same as the vertical guide 2. It is also possible to insert the tooth portion 3b from the horizontal direction directly below the base 10 between the horizontal direction of the yarn 8, and then lower the horizontal guide 3 and fix it in the coagulation bath. is there. Furthermore, there may be an aspect in which the edge portion 3a of the horizontal guide is not provided and the tooth portion 3b is independent. In short, it is only necessary that the tooth portion 3b is inserted between the yarns 8 in the horizontal direction immediately below the base, and then the horizontal guide 3 is lowered and fixed in the coagulation bath.

  By inserting the warp guide 2 and the horizontal guide 3 directly below the base, it is not affected by yarn fluctuations or the trajectory of the hollow fiber membrane 8 from the base discharge hole to the submerged direction changing guide 6 in the coagulation bath. Reliable splitting is possible. It is also possible to fix the splitting guide 1 directly below the base, and after spinning, the splitting guide 1 is lowered and fixed in the coagulation bath. Furthermore, although it is possible to form a lattice wire net shape in which the vertical guide 2 and the horizontal guide 3 are integrated, it is possible to separate the vertical guide and the horizontal guide in order to recover the yarn breakage trouble after the completion of the splitting. It is desirable.

  As shown in FIG. 1, the hollow fiber membrane 8 discharged from the base 10 travels while being converged and direction-changed by the liquid direction changing guide 6, but is hollow due to disturbance of the coagulating liquid flow, tension fluctuation of the hollow fiber membrane, and the like. The yarn film 8 tends to sway in the axial direction of the liquid direction change guide 6 on the surface of the liquid direction change guide 6, and when the shake becomes large, or the directions of the shakes of the adjacent hollow membranes become closer to each other. When this occurs, the hollow fiber membrane comes into contact with the dry part, resulting in fusion. The vertical guide 2 plays a role of preventing the fusion of the hollow fiber membrane in the liquid direction conversion guide shaft direction to prevent fusion.

  On the other hand, as is apparent from FIG. 1, the hollow fiber membrane 8 discharged from the die 10 is subjected to a tension in the oblique direction by the in-liquid direction changing guide 6, but generally a spinning dope for forming the hollow fiber membrane Has a low viscosity and a low spinning tension. Therefore, the hollow fiber membrane 8 discharged from the base 10 has a hollow fiber membrane trajectory of the dry part determined by the balance between the vertical drop direction and the oblique direction tension due to gravity, and the air flow fluctuation and coagulation bath liquid level fluctuation in the dry part, The swaying in the radial direction of the submerged direction conversion guide 6 occurs due to the speed fluctuation of the submerged direction conversion guide 6 and the overlap of the hollow fiber membranes 8 on the surface of the submerged direction conversion guide 6. The horizontal guide 3 serves to prevent radial fusion of the hollow fiber membrane 8 in the submerged direction conversion guide 6 and prevent fusion.

  In the present invention, the separation position of the splitting guide 1 is between the coagulation bath liquid level 5 and the in-liquid direction changing guide 6. The hollow fiber membrane 8 in the dry part is still in an incomplete state, and when the hollow fiber membrane 8 touches the fiber separation guide 1 in the dry part, the hollow fiber membrane surface is scratched or the hole on the hollow fiber membrane surface is crushed. Thus, the function as a hollow fiber membrane is impaired. As soon as the hollow fiber membrane 8 enters the coagulation bath solution, the hollow fiber membrane 8 starts to coagulate, and the surface of the hollow fiber membrane is formed. Therefore, even if the hollow fiber membrane 8 touches the fiber separation guide 1 in the coagulation bath, the function as the hollow fiber membrane is not impaired. However, since the hollow fiber membrane 8 is converged by the in-liquid direction conversion guide 6, the distance between the hollow fiber membranes becomes smaller as it approaches the in-liquid direction conversion guide 6. Therefore, it is desirable that the separation position of the splitting guide 1 is as far as possible from the liquid direction changing guide 6, that is, as close to the coagulation bath liquid level. In addition, the closer to the coagulation bath liquid level, the easier it is to observe the state of splitting and to recover from troubles such as thread breakage. The separation position of the splitting guide 1 is preferably 5 mm or more and 100 mm or less from the coagulation bath liquid level 5 so that the splitting guide 1 does not come out of the coagulation bath liquid level to the dry part even if there is some fluctuation of the coagulation bath liquid level. .

  The means for fixing the separating guide 1 may be any means as long as it is between the coagulation bath liquid level 5 and the in-liquid direction changing guide 6 and can securely fix the vertical guide 2 and the horizontal guide 3 in place, as shown in FIG. As described above, the bracket 4 may be provided on the wall surface of the coagulation bath 11, the fixing bracket may be taken from a stand outside the coagulation bath, and the fixing bracket may be suspended from the base.

  As described above, the plurality of hollow fiber membranes 8 discharged from the base 10 are arranged between the coagulation bath liquid surface 5 and the submerged direction conversion guide 6 provided in the coagulation bath. Since a plurality of hollow fiber membranes are separated for each single yarn by the fiber separation guide 1 made of 3 and run, there is no fusion due to contact between the hollow fiber membranes in the dry part, and the hollow is continuously stable. Yarn film can be manufactured.

  As the material for the splitting guide in the present invention, the same material as the conventional yarn guide forming material can be used as long as corrosion by the coagulating liquid does not occur. Specifically, high-hardness corrosion-resistant metals such as stainless steel and titanium, hard chrome plating, fluorine such as alumina, silicon carbide, titanium nitride, and Teflon (registered trademark), and coating with inorganic and organic materials such as silicone Examples thereof include ceramics such as metal, glass, alumina, and zirconia. Bakelite and other hard plastics can also be used. The surface state may be mirror-like or satin-like. Further, as the shape of the guide, in order to prevent the contact with the hollow fiber membrane and the generation of scratches on the surface of the hollow fiber membrane due to friction, it is preferable that the contact portion with the hollow fiber membrane has a smooth curved shape. A suitable example is a round bar-shaped guide.

  As a method for producing the hollow fiber membrane of the present invention, for example, a hollow fiber-like polymer fluid that is usually spun using a bicyclic die forms a porous material in the flow-down process, solidifies in a coagulation bath, and is washed. A method in which the core side fluid is washed in a bath, dried, crimped, and wound up can be employed.

  The hollow fiber membrane of the present invention is a hollow fiber-like porous membrane that is like a sponge. It is preferably used for liquid permeation, hemodialysis, blood filtration, etc., and preferably has an inner diameter of 100 to 1000 microns, a film thickness of 10 to 60 microns, and a diameter of 0.1 to 0.5 mm.

  FIG. 5 shows an example of a process for producing a hollow fiber membrane for an artificial kidney by a dry and wet spinning method. A plurality of hollow hollow fiber membranes 8 discharged from a spinneret 10 having a double ring structure are separated for each yarn by a separation guide 1 provided below the surface of the coagulation bath, and a coagulation bath 11. After passing through the washing bath 12 and the drying device 13, the paper is taken up by the take-up roll 14, crimped by the crimping device 15, taken up by the take-up roll 16, and taken up by the winder 17. 18 is a wet hollow fiber membrane, 19 is a dry hollow fiber membrane, and 20 is a dry hollow fiber membrane to which crimps are imparted.

  Examples of the membrane material of the hollow fiber membrane of the present invention include a membrane material made of a hydrophobic polymer or a blend membrane of a hydrophobic polymer and a hydrophilic polymer. Examples of the hydrophobic polymer include cellulose, cellulose acetate, polyacrylonitrile, polysulfone, and polyethersulfone. Among them, polysulfone is preferably used. Examples of the hydrophilic polymer include polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene imine, dextran or a derivative thereof, polyacrylic acid, and polymethacrylic acid. Among them, polyvinyl pyrrolidone is preferably used. As the membrane material, these hydrophobic polymers may be used alone or a plurality of hydrophobic polymers may be blended. A blend of a hydrophobic polymer and a hydrophilic polymer may be used, but a blend film of polysulfone and polyvinyl pyrrolidone is preferably used from the viewpoint of film forming properties and membrane performance.

  The module incorporating the hollow fiber membrane of the present invention is suitably used for artificial kidneys, microfiltration, ultrafiltration, reverse osmosis, gas separation, nitrogen enrichment, oxygen enrichment, blood purification, and the like.

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

Example 1
16 parts of polysulfone ("Udel" P-3500 manufactured by Teijin Amoco), 4 parts of polyvinylpyrrolidone (K30 manufactured by BASF), 2 parts of polyvinylpyrrolidone (K90 manufactured by BASF) are added to 77 parts of dimethylacetamide and 1 part of water. It was heated and dissolved at 14 ° C. for 14 hours. This film-forming stock solution is discharged from a base 10 shown in FIG. 2A in which 32 orifice-type double cylindrical discharge holes having an outer diameter of 0.3 mm and an inner diameter of 0.2 mm are arranged, and 64 parts of dimethylacetamide as a core liquid. A solution composed of 36 parts of water was discharged, passed through a dry length of 350 mm, and then led to a coagulation bath 11 filled with a solution consisting of 20% by weight of dimethylacetamide and 80% by weight of water, and a liquid provided 600 mm below the surface of the coagulation bath. After converging and changing the direction by a middle direction conversion guide 6 and taking up with a roll 7 provided above the coagulation bath, it is split into yarns using a vertical guide 2 and a horizontal guide 3 directly under the base, and a split guide 1 Was fixed at a position 20 mm below the liquid level of the coagulation bath. The arrangement of the discharge holes was set to X1 = 20 mm, X2 = 6 mm, Y1 = 20 mm, and Y2 = 40 mm shown in FIG. Further, the tooth guides 2b and 3b of the side guide 2 and the side guide 3 that actually divide the hollow fiber membrane 8 are round bars made of stainless steel having a diameter of 3 mm and hard chrome plating on the surface. Then, it passed through the water washing bath and the drying processing apparatus which were filled with water. Next, crimping was performed using a multi-blade type roll, and winding was performed with a winder to obtain a hollow fiber membrane. During the operation for 3 consecutive days, troubles such as yarn breakage did not occur at all.

(Comparative Example 1)
Spinning was carried out in the same manner as in Example, without using a fiber separation guide. As a result, the fusion due to the contact of the hollow fiber membrane in the dry part frequently occurred, the yarn breakage occurred, and the yarn could not be hooked up to the winder.

  The hollow fiber membrane production method and production apparatus of the present invention are used for blood dialysis as described above, as well as for wide applications such as purification of sewage, production of drinking water, humidifiers for fuel cells, etc. Can do.

It is a side view which shows an example of the dry-wet spinning apparatus in this invention. It is a schematic plan view which shows an example of the state by which the hollow fiber membrane was divided | segmented for every thread | yarn by the splitting guide in this invention. It is a schematic plan view which shows another example of the state by which the hollow fiber membrane was divided | segmented for every thread | yarn by the fiber separation guide in this invention. It is a schematic plan view which shows another example of the state by which the hollow fiber membrane was divided | segmented for every thread | yarn by the fiber separation guide in this invention. It is a plane schematic diagram which shows an example of the fiber separation method by the length guide of this invention. FIG. 4 is a schematic side view of FIG. It is a plane schematic diagram which shows an example of the fiber separation method by the horizontal guide of this invention. FIG. 5 is a schematic side view of FIG. It is process drawing which shows the hollow fiber membrane manufacturing process for artificial kidneys.

Explanation of symbols

1: Splitting guide 2, 2 ′, 2 ″: Vertical guide 2a, 2a ′, 2a ″: Edge of the vertical guide 2b, 2b ′, 2b ″: Vertical portion of the guide 3, 3 ′, 3 ″: Horizontal guide 3a, 3a ′, 3a ″: edge portion of the horizontal guide 3b, 3b ′, 3b ″: tooth portion of the horizontal guide
4: Bracket
5: Coagulation bath liquid level
6: In-liquid direction conversion guide
7: Roll
8: Hollow fiber membrane
9: Hollow fiber membrane bundle
10: Base
11: Coagulation bath

Claims (6)

A plurality of hollow fiber membranes in a method of manufacturing the dry-wet spinning method, into a coagulation bath placed submerged redirecting guide, minute fiber guide arranged between the coagulation bath liquid surface and the liquid redirecting guide A method for producing a hollow fiber membrane, wherein a plurality of hollow fiber membranes are separated for each yarn by the fiber separation guide and run. After the hollow fiber membranes of the plurality of to minute fiber just below the mouthpiece by the minute fiber guide, hollow fiber of claim 1, the component fiber guide moves in a coagulation bath liquid plane, characterized in that securing A method for producing a membrane. In semi-wet spinning apparatus for manufacturing a plurality of hollow fiber membranes, we established a submerged redirecting guide into a coagulation bath, a minute fiber guide provided further between the coagulation bath liquid surface and the liquid redirecting guide An apparatus for producing a hollow fiber membrane. The apparatus for producing a hollow fiber membrane according to claim 3 , wherein the splitting guide includes a vertical guide and a horizontal guide. The apparatus for producing a hollow fiber membrane according to claim 3 or 4 , wherein the splitting guide is movably provided. The apparatus for producing a hollow fiber membrane according to any one of claims 3 to 5 , further comprising fixing means for fixing the vertical guide and the horizontal guide in a coagulation bath.

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