JPS6051364B2 - Manufacturing method of fluid separation shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fluid separation shaft.
A semi-permeable membrane layer is provided on the outer surface of the core shaft.

The present invention relates to a method of manufacturing a fluid separation shaft of constant length. It has been known for a long time to obtain fresh water by desalinating salt water or seawater using the principle of reverse osmosis. A semipermeable membrane is used that has no permeability to salts such as sodium and magnesium chloride. In order to utilize this technology industrially, semipermeable membranes formed in various forms are used. Above all,
When using a fluid separation shaft in which a porous layer is formed on the outer surface of a hollow core shaft having a through hole in the wall surface or a core shaft having grooves in the longitudinal direction, and a semipermeable membrane layer is further formed on the outer peripheral surface of the core shaft. Because the core shaft has pressure resistance, excellent membrane performance is guaranteed even when used under high pressure, and when the fluid separation shafts are tightly bundled to form a fluid separation device, the Advantages include the ability to accommodate large membrane areas.

However, when manufacturing conventional fluid separation shafts,
Generally, since a hard core shaft with high rigidity is used, the separating shaft has poor flexibility, making it difficult to wind up the core shaft after the film-forming liquid has been applied, and the coating during coagulation. If the solidification rate of the membrane layer is slow and the roll is brought into contact with the membrane surface before solidification is completed, problems such as membrane formation will be inhibited and membrane performance will be significantly reduced. The disadvantage was that it was difficult to manufacture.

The present invention has been made to eliminate such drawbacks, and by using a take-off unit to take up and cut the continuous core shaft coated with a film-forming liquid without applying it to a roll, It is an object of the present invention to provide a method for manufacturing a fluid separation shaft that can efficiently obtain a separation shaft of a constant length without causing a decrease in membrane performance.

The gist of the present invention is that a membrane-forming solution containing a semipermeable membrane-forming material as a component is applied to the outer surface of a porous layer of a core shaft, and then the membrane-forming solution is applied to a circulating endless band before or after being immersed in a coagulation bath. The core shaft is gripped by grips provided on at least three pulling tools arranged at equal intervals of S゛, and then the core shaft is cut to a constant S゛ by a cutting tool, and the endless The present invention resides in a method of manufacturing a fluid separation shaft, characterized in that the cut core shaft is removed from one gripping portion of a pulling tool that precedes the band.

Next, the method for manufacturing the fluid separation shaft of the present invention will be explained in more detail.

FIG. 1a shows a cross section of an example of a fluid separation shaft 1 to be obtained in the present invention, in which a through hole 5 is formed in the wall surface of a hollow core shaft 2 made of a material such as metal or synthetic resin. and a porous layer 4 is provided on the outer peripheral surface of the core shaft 2,
Furthermore, a semipermeable membrane layer 7 is provided on the outer peripheral surface of the porous layer 4.

FIG. 1b shows a cross section of another example of the fluid separation shaft 1 to be obtained in the present invention, in which grooves 6 are formed in the longitudinal direction on the wall surface of the core shaft 2 made of materials such as synthetic resin and metal. A porous layer 4 is provided on the outer peripheral surface of the core shaft 2, and a semipermeable membrane layer 7 is further provided on the outer peripheral surface of the porous layer 4. The porous layer 4 supports the semipermeable membrane layer 7 and has pores through which fluid flows, and is made of a nonwoven fabric, a woven fabric, a laminate of a woven fabric and a nonwoven fabric, or a synthetic material having communicating pores. A resin film or the like is used.

The semipermeable membrane layer 7 has the property of selectively permeating specific components in the fluid, and examples of the semipermeable membrane forming material include cellulose such as cellulose acetate, cellulose propionate, cellulose butyrate, and ethyl cellulose. Polyamide polymers such as aromatic polyamides, pipewodine polyamides, polybenzimidazole, polysulfone, polyvinyl chloride, polyacrylonitrile and the like are suitable for use. The thickness of the semipermeable membrane layer 7 is 0.7
Micron to 500 micron. A membrane-forming material dissolved in a solvent is used as a membrane-forming solution, to which additives, fillers, etc. for forming micropores are added as necessary. In particular, when cellulose acetate is used as a membrane-forming material, a membrane-forming solution consisting of acetone as a solvent and one or more of formamide, magnesium perchlorate, organic acids, water, urea, etc. as additives for forming micropores. It is preferable to use The viscosity of the film-forming liquid is preferably adjusted to a viscosity range of 50 to 300 voices. Examples of steps in the method for manufacturing a fluid separation shaft of the present invention are shown in FIGS. 3 and 4.

The core shaft 2 used in the method of manufacturing a fluid separation shaft of the present invention is a second
It is similar to the examples shown in Figures a and b, and a porous layer 4 is previously formed on the outer peripheral surface.

In FIG. 3, a core shaft 2 on which a porous layer 4 is formed is shown.
is wound around a winding frame 8 as a continuous core shaft 2, and the core shaft 2 pulled out from the winding frame 8 passes through a center hole 10 of an extrusion mold 9.

The extrusion mold 9 is provided with a membrane forming liquid supply port 11, and the membrane forming liquid supplied from the storage tank 23 by the pump 12, gas pressure, etc. is discharged from the annular orifice end 13, and is formed to a certain thickness. is applied to the outer peripheral surface of the core shaft 2 in the form of a film. On the front side of the extrusion die 9, an endless band 14 having a straight line section parallel to the center hole 10 is provided, and the endless band 14 is configured to circulate around the center hole 10. The endless band 14 is preferably formed of a chain, a belt, or the like. Three pulling tools 15 are arranged on the endless band 14 at approximately equal intervals S. FIGS. 5A, 5B, and 5C show an example of a pulling tool used in the method of manufacturing a fluid separation shaft of the present invention. The take-off tool 15 in FIG. 5a is provided with a grip part 16.

The gripping portion 16 grips the core shaft 2 coated with the film-forming liquid on the porous layer 4 by widening the gap between the pair of gripping plates facing each other or pinching the core shaft 2, and removes the film-forming liquid from the core shaft 2. It is possible to do so. The core shaft 2 is gripped by a grip part 16 of a pulling tool 15 near the extrusion die 9 and pulled off at a constant speed.
Appropriate tension is applied to the core shaft 2 by the center hole 10 of the extrusion mold 9 and the pulling tool 15, or by the pinch roll 17 and the pulling tool 15. After the gripping part 16 of the pulling tool 15 has been gripped, the cutting tool 18 provided in the vicinity of the pulling tool 15 of the endless band 14 and in front of the installation location)
Accordingly, the pulling tool 15 and the pulling tool 1 preceding the endless band 14
5, the core shaft 2 is cut. Cutting tool 1 in this case
8 moves from above to below. After cutting or at the same time as the cutting, the gripping pieces of the gripping part 16 of the pulling tool 15 are opened, and the core shaft 2 cut to a certain length is released from the gripping part 16. FIG. 5b shows another example of the take-off tool 15, in which two grips 16 are provided at the front and rear.

The cutting tool 18 has two gripping parts 16116. provided in between. The cutting tool 18 in this case moves laterally. in this case,
The core shaft 2 on which the film-forming liquid is applied on the porous layer 4 is placed in an extrusion mold 9
Two grips 16116 of the pulling tool 15 near the. It is gripped by the robot and pulled out at a constant speed. Then, the cutting tool 18 is operated and the core shaft 2 is cut. After or at the same time as the cutting, the front gripping part 161 of the pulling tool 15 and the rear gripping part 162 of the pulling tool 15 that precedes this are simultaneously opened, and the core shaft 2, which has been cut to a certain length, is gripped. Part 16
Forced to leave 1162. It is also possible to use the one shown in FIG. 5c instead of the above-mentioned pulling tool 15. In this case, the pulling tool 15 has two gripping portions 16 at the front and rear.
1162, cutting is performed by a cutting tool 18 provided outside the endless band 14, and the intermediate portion held by the front gripping portion 161 and rear gripping portion 162 of the core shaft 2 is cut. Ru.

The cutting tool 18 in this case moves from above to below. Third
In the illustrated example, the endless band 14 is installed such that a portion thereof is immersed in a coagulation bath 19 containing water, for example, and is rotated within the coagulation bath 19 at a constant speed by a drive motor 20. The core shaft 2 pulled out from the extrusion mold 9 is in the coagulation bath 1
9, the mixture is moved through the gas phase for a short time, preferably 1 to 3 minutes, during which time a suitable amount of the solvent evaporates from the coating layer.

Next, the core shaft 2 is immersed in a coagulation bath 19, and the solvent remaining in the coating layer is replaced with the water in the coagulation bath, so that the coating layer is coagulated, and fine particles are formed on the outer surface. A semipermeable membrane-shaped layer 7 with an active layer is formed. Coagulation bath 1 of the core shaft 2
9 can be carried out at any arbitrary position, for example, after gripping the core shaft 2 with the grip part 16, cutting it, and separating it from the grip part 16 in the gas phase, The core shaft 2 can also be coagulated by immersing it in a coagulation bath 19 provided at a different position.

In FIG. 4, six pulling tools 15 are arranged on the circulating endless band 14 at approximately equal intervals S, and the endless band 14 is composed of an inclined area 21 and a horizontal area 22. The core shaft 2 is detached from the grip portion 16 in a horizontal region 22. The coagulation process of the coating layer in the coagulation bath 19 generally proceeds slowly, and in most cases it takes 2 to 6 coats to complete the coagulation. On the other hand, in order to manufacture the fluid separation shaft industrially, it is necessary to increase the drawing speed as much as possible, so the drawing and cutting of the core shaft 2 should be carried out before the solidification of the coating layer is completed. is preferred. In FIGS. 3 and 4, it is preferable that the pulling angle of the core shaft 2 by the pulling tool 15 is maintained at 45 degrees below the horizontal direction, and in such a case, the drooping of the coating layer is almost negligible. Therefore, unevenness in the film thickness in the axial direction due to drooping of the semipermeable film layer 7 of the core shaft 2 is suppressed.

For this reason, in FIG. 3, the endless band 14 is provided with a slope as a whole, and in FIG. 4, the endless band 14 has an inclined region 21. In the method for manufacturing the fluid separation shaft of the present invention, the formation of the microporous structure of the semipermeable membrane when the membrane forming liquid is immersed in the coagulation bath is not inhibited.
Fluid separation shafts of approximately S constant length can be manufactured continuously.

The fluid separation shaft of the present invention can be applied, for example, to the following cases. (b) Collection of fresh water from salt-containing water (portion) Softening of hard water (c) Concentration of liquids containing heavy metal ions and radioactive components (d) Purification and concentration of solutions using organic liquids as solvents (e)
Separation of mixed gases When applied to such fields, it is also possible to employ any of the reverse osmosis method, ultrafiltration method, and dialysis method as a separation means.

Example A hollow core shaft 2 made of polypropylene resin having a diameter of 3 TWL was provided with a porous layer 4 made of a polyester fiber braid on the outer surface.

Cellulose acetate (acetylation degree 39
．． 8%), 35% by weight of acetone, and 45% by weight of formamide were mixed and dissolved, and the resulting mixture was injected into the storage tank 23, and then fed to the extrusion mold 9 by the metering pump 12. Using an apparatus such as that shown in FIG.
The endless strip 14 was rotated in the coagulation bath 19 at a speed of 10 n1/min by the drive motor 22 while holding the core shaft 2 coated on top so that the take-up angle was 10 layers. The gripping part 16 of the pulling tool 15 grips the core shaft 2, and after cutting it with the cutting tool 18, the gripping part 16 is released, and the core shaft 2 is cut by the cutting tool 18.
The core shaft 2 cut to a length of was left in a coagulation bath 19 maintained at a water temperature of 3°C. After 5 hours, the fluid separation shaft 1 was taken out of the coagulation bath 19 and immersed in 70°C heated water for 3 minutes.
was attached to a reverse osmosis test cell, and the amount of water permeation was measured using 0.5% saline solution pressurized to 40k9/CIL.

As a result, the water permeability rate was 1.0 H/day/day, and the salt rejection rate was 97.
It was %.

[Brief explanation of drawings]

1A and 1B are cross-sectional views showing an example of a fluid separation shaft manufactured according to the present invention, and FIGS. 2A and 2B are sectional views showing an example of a core shaft,
Figure 3 is a process diagram showing one embodiment of the method of the present invention, Figure 4 is a process diagram showing another embodiment of the method of the present invention, and Figures 5a, b, and c are enlargements of the vicinity of the pulling tool used in the method of the present invention. There is a front view. FIG. 6 is an enlarged perspective view of the vicinity of the take-up tool in FIG. 5a. Explanation of symbols, 1...Fluid separation axis, 2...
...Core axis, 4... Porous layer, 5...
Through hole, 6... Groove, 7... Semipermeable membrane layer, 8... Winding frame, 9... Extrusion mold, 10
... Center hole, 14 ... Endless band, 15.
...Retrieval tool, 16...Gripper, 18...
... Cutting tool, 19 ... Coagulation bath, 20 ... Drive motor.

Claims (1)

[Claims] 1. Before or after immersing a membrane-forming solution containing a semipermeable membrane-forming material on the outer surface of the porous layer of the core shaft in a coagulation bath, the membrane-forming solution containing a semipermeable membrane-forming material as a component is applied to the rotating endless band at approximately equal intervals. The core shaft is gripped by grips provided on at least three pulling tools, and then the core shaft is cut to a substantially constant length by a cutting tool, and the preceding pulling tool of the endless band is cut into a substantially constant length. A method for manufacturing a fluid separation shaft 2, characterized in that the cut core shaft is removed from a gripping part of a tool. Method 3 for manufacturing a fluid separation shaft as described in Scope 1: Make sure that the pulling angle of the core shaft coated with the membrane-forming liquid on the outer surface of the porous layer is maintained at 45° or less with respect to the horizontal direction using a pulling tool. Method 4 for manufacturing a fluid separation shaft according to claim 1 or 2: Cutting a core shaft whose porous outer surface is coated with a membrane-forming liquid using a cutting tool provided near a pulling tool. A method for manufacturing a fluid separation shaft according to any one of claims 1 to 3, characterized in that: