JPS6322162B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to a method for producing hollow fibers for blood treatment. More specifically, the present invention relates to a method for producing hollow fibers used in, for example, blood processing devices, in which the internal liquid of the fibers is washed and removed by a specific method. Prior Art Hollow fibers conventionally used for dialysis treatment of blood and the like include cellulose-based materials such as regenerated cellulose and cellulose acetate, polysulfone, polyacrylonitrile, and polymethyl methacrylate.
Among these, those currently in practical use are mainly regenerated cellulose made from copper ammonia cellulose, and these are excellent as they have sufficient strength in a wet state. When the hollow fiber for dialysis is used for hemodialysis or the like, it is desirable that the hollow fiber be circular because if the circular cross section is distorted, blood coagulation etc. will occur and the dialysis effect will be significantly reduced. Traditionally, hollow fibers are produced by extruding cellulose-based spinning dope through an annular spinning hole into air or a non-coagulating liquid.
At that time, a non-coagulable liquid (internal liquid) for the spinner dope is introduced into the center of the linear spinning dope and discharged, and then passed through the linear spinning dope formed in this way to solidify. It is manufactured by regenerating it, washing it, treating it with glycerin if necessary so as not to reduce its dialysis ability, and then drying it (Japanese Patent Publication No. 53-30808, Japanese Patent Publication No. 57-199808).
No. etc.). Internal fluids such as isopropyl myristate contained in hollow fibers are considered to be harmful to the human body, so when using them in hemodialysis equipment, etc., they must be washed and removed before use. There is a need. As a method for removing and cleaning the internal liquid of such hollow fibers, (1) a method of flowing a chlorofluorohydrocarbon or a mixture of this and a substance capable of forming an azeotrope into the hollow fiber (in particular, (2) A method in which the hollow fiber bundle is washed with a low boiling point organic solvent and then dried, and then the ends of the hollow fiber bundle are fixed to a case (Special (3) A method in which a hollow fiber bundle is loaded into a case, both ends of which are potted and fixed to the case, and the potted portions are cut and opened. Method of applying centrifugal force (Japanese Patent Publication No. 57-6363), (4) fixing both ends of the hollow fiber bundle with potting material, cutting the fixed part to open both ends, and flowing the lower alcohol in this state. Method of cleaning by washing
No.) etc. have been proposed. However, in methods (1), (2), and (4), the internal liquid is not sufficiently removed by physical methods and is removed only by the cleaning power of the solvent, which results in insufficient removal of the internal liquid. However, in order to sufficiently remove the internal liquid, a large amount of cleaning solvent is required. On the other hand, when immersion cleaning or circulation cleaning is performed, the removed internal liquid comes into contact with the inner and outer surfaces of the hollow fibers again, so there is a drawback that the cleaning effect cannot be sufficiently exerted. In addition, methods that do not involve forced evacuation of the hollow space during drying after cleaning have the disadvantage that the cleaning solvent remains. Furthermore, in the case without forced exhaust, the bundle of hollow fibers was densely packed, and the internal liquid that adhered to the outside of the hollow fibers without being removed by the cleaning solvent sometimes remained in the densely packed parts. Furthermore, in the above method, when the hollow fibers produced by continuous spinning are cut into predetermined dimensions and bundled, internal liquid adheres to the outside of the hollow fibers from the cut end and in the vicinity of the cut end. When fixing the end portions with a potting material, the potting effect may be reduced, resulting in poor fixation. Furthermore, if the drying process is performed without sufficiently removing the internal liquid or cleaning liquid adhering to the outside of the hollow fibers, the internal liquid interposed between the outer surfaces of the hollow fibers may stick together, causing the hollow fibers to stick together.
In this case, during the subsequent manufacturing process, when a force was applied to separate the bonded hollow fibers, pinholes were formed on the hollow fiber membrane surface, and blood leaked from the holes. Furthermore, in method (3), it is extremely difficult to completely remove the internal liquid using only centrifugal force, and there is a risk that the cross section may be deformed. OBJECT OF THE INVENTION Therefore, an object of the present invention is to provide a novel method for producing hollow fibers. Another object of the present invention is to provide a method for manufacturing hollow fibers used in blood processing devices and the like, in which the internal liquid of the fibers is washed and removed by a specific method. These objectives are to obtain a hollow fiber bundle by cutting cellulose-based hollow fibers containing a non-coagulable liquid spun from a cellulose-based spinning dope, and to force the internal non-coagulable liquid from one end of the hollow fiber bundle. At the same time, a cleaning solvent with high solubility in the internal non-coagulable liquid and high volatility is forced to flow inside and outside the hollow fibers, and then a gas is forced to flow inside and outside the hollow fibers. This is achieved by a method for producing hollow fibers for blood treatment, which is characterized by the following. Further, the present invention is a method for producing a hollow fiber for blood treatment, in which the internal non-coagulable liquid is forcibly removed by exhausting the internal non-coagulable liquid by suction ventilation or forced ventilation. Furthermore, the present invention is a method for producing hollow fibers for blood treatment, in which the internal non-coagulable liquid is forcibly removed by standing up the hollow fiber bundle and letting it flow down. The present invention is a method for producing a hollow fiber for blood treatment, in which the forced circulation of a cleaning solvent is carried out by suction or forced circulation of the cleaning solvent. Further, the present invention is a method for producing a hollow fiber for blood treatment, in which the forced flow of the cleaning solvent is carried out by circulating the cleaning solvent into and out of the hollow fiber by centrifugal force. Further, in the present invention, forced circulation of the cleaning solvent is performed by standing the hollow fiber bundle vertically on a horizontal surface, allowing the cleaning solvent to flow through the lower end, and overflowing the cleaning solvent from the upper end. This is a method for producing hollow fibers for blood treatment. The present invention also provides forcible removal of internal non-coagulable liquid;
This is a method for manufacturing hollow fibers for blood treatment, in which forced circulation of a cleaning solvent is performed at the same time. DETAILED DESCRIPTION OF THE INVENTION Next, a method for producing a hollow fiber for blood treatment according to the present invention will be described with reference to the drawings. That is, FIGS. 1 to 3 are process schematic diagrams for explaining the basic principle of the method of the present invention. As is clear from the figure, first, hollow fibers that are continuously spun from a cellulose-based spinner stock solution and contain a non-coagulable liquid (internal liquid) are cut into predetermined lengths and bundled. A hollow fiber bundle 2 is obtained by putting it into a tube 1. A suction cap 3 is fitted to one end of this cleaning outer cylinder 1, and the suction cap 3 is connected to a suction device 5 such as a vacuum pump via a conduit 4, and the suction device 5a is operated. Hollow fiber bundle 2
The internal liquid that has filled the inside of the hollow fibers that make up the structure and is also attached to a part of the outer surface is removed by suction.
Next, as shown in FIG. 2, when the hollow fiber bundle 2 is brought into contact with the cleaning solvent 6 at the open end on the reaction side of the suction cap 3 and the suction device 5b is activated, the cleaning solvent 6 is absorbed by its suction force. Both the inside and outside of the hollow fibers are circulated and cleaned. Furthermore, the third
As shown in the figure, the hollow fiber bundle 2 is pulled up from the cleaning solvent 6, and a gas, such as air, nitrogen gas, carbon dioxide gas, etc., is supplied from the open end by the gas supply device 7, preferably air, and most preferably hot air (for example, ~90
The cleaning solvent is removed by drying the hollow fibers by forcing gas to flow through both the inside and outside of the hollow fibers by operating a suction device. In addition, in this method, the suction devices 5a, 5b, 5c
The same one may be used, or a different one may be used separately for each step. In addition, in the above method, the forced removal of the non-coagulable liquid shown in Fig. 1 is carried out by using a normal pump, blower, etc. instead of a suction device to forcefully send gas such as air, nitrogen, carbon dioxide, etc. Of course, the pressure feeding and suction may also be used together. Further, regarding the forced circulation of the cleaning solvent shown in FIG. 2, a pump or the like may be used instead of the suction device to cause the cleaning solvent to flow in the opposite direction. Furthermore, the third
Regarding the forced circulation of gas shown in the figure, a normal pump, blower, etc. may be used instead of a suction device to circulate gas such as air, especially warm air, or the pressure feeding and suction may be used in combination. . The cleaning outer cylinder 1 and the suction cap 3 may be made of any material as long as it is not attacked by cleaning solvents, and are usually polypropylene, polyethylene, polycarbonate, or the like. The cleaning solvent may be any solvent as long as it has high solubility in the non-coagulable liquid that is the internal liquid, has a large cleaning effect, and is relatively volatile. For example, dichloromethane, 1,1,1-trichloroethane, Fronsolve ( _CCl2F - _CClF2 ,
Asahi Glass Co., Ltd. product name), Solmics AP-1
(85.6% ethanol, 1.1% methanol, 13.3% isopropanol, trade name manufactured by Nippon Alcohol Sales Co., Ltd.), and particularly preferred are dichloromethane and 1,1,1-trichloroethane. The cellulose-based spinning stock solution used in the method of the present invention includes metal ammonia cellulose such as cuprammonium cellulose, viscose, etc., but preferably cuprammonium cellulose,
For example, a permeation performance control agent (pore size control agent) such as one manufactured by a conventional method from cellulose having an average degree of polymerization of 500 to 2500, and as described in JP-A-57-199808, if necessary. may also be blended. Such spinning dope usually has a specific gravity of 1.05 to 1.15.
and preferably 1.06 to 1.10. However, as will be described later, the linear spinning dope extruded from the spinning hole is filled with a non-coagulable liquid, so the specific gravity is usually lower than that of the spinner dope, and is 1.00~1.00.
1.08, preferably 1.01 to 1.04. The non-coagulable liquid for the cellulose-based spinning dope used as the lower layer has a bulk specific gravity larger than that of the linear spinning dope [spinning dope containing a non-coagulable liquid (internal liquid)] and a larger specific gravity than the coagulable liquid; It is a halogenated hydrocarbon that has low solubility in water and low surface tension, and its specific gravity is usually 1.3 or more, preferably 1.4 to 1.7. For example, carbon tetrachloride (d ²⁰ ₄ = 1.632 water solubility 0.08
g/20℃−100mlSurface tension (25℃)26.8dyne/
cm), 1,1,1-trichloroethane (d ²⁰ ₄ =
1.349), 1,1,2-trichloroethane (d ²⁰ ₄ =
1.442), trichlorethylene (d ¹⁵ = 1.440, water solubility 0.11g/25℃-100ml, surface tension (25℃)
31.6dyne/cm), tetrachloroethane (d ²⁵ ₀ =
1.542), tetrachlorethylene (d ⁰ = 1.656, water insoluble), trichlorotrifluoroethane (d ²⁵ =
1.565, water solubility 0.009g/21℃-100ml, surface tension (25℃) 19.0dyne/cm), etc. Among these, the solubility in water is 0.05g/21℃-100
ml or less and a surface tension (25°C) of 20 dyne/cm or less provides extremely good spinnability. Examples of such non-coagulable liquids include tetrachlorethylene, trichlorotrifluoroethane, and the like. Therefore, the height of the non-coagulable liquid layer varies depending on the spinning speed, but is usually 50 to 250 mm.
Preferably it is 100 to 200 mm. In addition, the selection of the non-coagulable liquid (internal liquid) to be introduced and filled into the linear spinning dope greatly influences the maintenance of the hollow portion of the hollow fiber and the presence or absence of irregularities on the wall surface of the hollow fiber. That is, when the non-coagulable liquid filled in the hollow fiber is suddenly discharged to the outside through the membrane when the hollow fiber is dried, the pressure inside the hollow becomes reduced, causing collapse of the hollow or unevenness on the inner wall. The non-coagulable liquid used is selected from liquids that have low permeability and low specific gravity when dried. That is, the specific gravity of a cellulose-based spinning stock solution is usually 1.05 to 1.15, for example, in the case of a cuprammoniac cellulose-based spinning stock solution, the specific gravity is approximately 1.05 to 1.15.
1.08, the bulk specific gravity of the linear spinning dope containing the non-coagulable liquid is 1.00 to 1.08, preferably
The specific gravity of the non-coagulable liquid should be selected from a range of 1.01 to 1.04, for example about 1.02, and is usually 0.65 to 1.00, preferably 0.70 to 0.90, for example about 0.85. Examples of suitable non-coagulable liquids include n-hexane, n-heptane, n-octane, n-decane, n-dodecane,
Liquid paraffin, isopropyl myristate, light oil, kerosene, benzene, toluene, xylene, styrene, ethylbenzene, etc. The coagulating liquid for the cellulose-based spinning dope is an alkaline aqueous solution that has a specific gravity lower than that of the non-coagulating liquid in the lower layer, and usually has a specific gravity of 1.03 to 1.10. Examples of the alkali include sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide, with sodium hydroxide being preferred. Its concentration is 30~ in terms of sodium hydroxide.
150g-NaOH/, preferably 35-80g-
NaOH/, most preferably 40-60g
NaOH/, especially about 50g-NaOH/
(approximately 4.8% by weight, d=1.055). However,
The distance from the interface with the non-coagulable liquid to the end of the deflection rod is usually 5 to 30 mm, preferably 10 to 20 mm. Although the cuprammonium cellulose hollow fibers produced by the floating spinning method have been described above, the present invention is not limited to this method.
At that time, a non-coagulable liquid for the spinning dope is introduced and discharged into the center of the spinning dope to be spun linearly, and after it is fully elongated by its own weight, an acid Alternatively, it is also possible to use a method for producing hollow fibers by immersing the fibers in an alkaline solution to coagulate and regenerate, then washing, and if necessary, treating with glycerin, followed by drying, or other known methods. FIG. 4 shows another embodiment of the present invention,
After removing at least most of the internal liquid from the hollow fiber bundle 2 in the cleaning outer cylinder 1 by the method described above, the hollow fiber bundle 2 is stood vertically on a horizontal surface,
The cleaning solvent is passed through the inner and outer surfaces of the hollow fibers constituting the hollow fiber bundle 2 from the lower end, overflows from the open end at the upper end, and then dried by the method described above. FIG. 5 shows still another embodiment of the present invention, in which at least most of the internal liquid is removed from the hollow fiber bundle 2 in the cleaning outer cylinder 1 by the method described above, The hollow fiber bundle 2 is set in the opening 11 of the weir 10 in the center of the rotary plate 9, and when the cleaning solvent is supplied through the conduit 12 on the rotary plate while rotating the rotary plate 9, the centrifugal force causes the hollow fibers to move inside and outside. It will be distributed on both sides. The hollow fiber bundle through which the cleaning solvent was forced to flow in this manner is dried by the method described above. The hollow fiber produced by the above method is used in an artificial kidney, that is, a hollow fiber type dialyzer, as shown in FIG. This dialyzer 21 has inlet tubes 2 for dialysate attached to both ends.
A hollow fiber bundle 2 made of a large number of hollow fibers is placed in a cylindrical body 24 provided with a hollow fiber bundle 2 and an outlet pipe 23, respectively.
After inserting the cylindrical body, both ends thereof are sealed together with both ends of the cylindrical body using potting agents 26 and 27 such as polyurethane, for example, a structure similar to a seal-and-tube type device in a heat exchanger. Headers 30 and 31 each having an inlet 28 and an outlet 29 for blood are brought into contact with both ends of the cylindrical body 24, and caps 33 and 34 connect the headers 30 and 31 to each other.
0, 31 and the cylindrical main body 24 are fixed to each other. Therefore, the inlet port 28 and the outlet port 2
Tubes 34 and 35 connected to the human body are connected to 9. Next, the present invention will be explained in more detail by giving Examples. Example 1 Hollow fibers recycled from copper ammonia cellulose with a wall thickness of 12 μm and an outer diameter of 224 μm, containing isopropyl myristate as an internal liquid, were cut into lengths of 26 cm, and 10,000 fibers were bundled to form a polypropylene cleaning cylinder. to obtain a hollow fiber bundle. This hollow fiber bundle 2 is transferred to a suction device 5 using the device shown in FIGS. 1 to 3.
The internal liquid was forcibly removed by activating the a switch and suctioning for 5 minutes. Then, after immersing the open end in dichloromethane, the suction device 5b was activated to flow 500 ml of the dichloromethane. moreover,
The suction device 5c was activated to suck and circulate hot air at 70 to 80° C. for 5 minutes. At this time, the measurement results of the glycerin content, residual internal liquid, and residual cleaning solvent in the hollow fibers were as shown in Table 1. Further, an artificial kidney as shown in FIG. 6 was prepared using the hollow fibers thus obtained, and both ends thereof were fixed using a segmented polyurethane potting agent. Next, dialysate was introduced from the inlet pipe 22 and discharged from the outlet pipe 23, while the dialysate was heated to 1000 mmHg (gauge pressure).
Blood was introduced from the blood inlet 28 and discharged from the outlet 29, and the state of blood leakage on the hollow fiber membrane surface or potting portion was examined, and the results were as shown in Table 1. Example 2 A hollow fiber bundle whose internal liquid had been forcibly removed in the same manner as in Example 1 was immersed vertically in 1,1,1-trichloroethane using the apparatus shown in FIG. By overflowing said 1, 1,
1-Trichloroethane was circulated, and then hot air was sucked and circulated for 5 minutes in the same manner as in Example 1.
The measurement results similar to those in Example 1 were as shown in Table 1. Further, an artificial kidney was prepared using this hollow fiber bundle in the same manner as in Example 1, and a blood leak test was conducted, and the results were as shown in Table 1. Comparative Example 1 A hollow fiber bundle similar to that in Example 1 was potted at both ends without forcibly removing the internal liquid, then washed by flowing dichloroethane only inside the hollow fibers, and then heated at 70 to 80°C. When the sample was dried by circulating hot air and the same measurements as in Example 1 were performed, the results shown in Table 1 were obtained. Furthermore, an artificial kidney was prepared using this hollow fiber and a leak test similar to that in Example 1 was conducted, and the results were as shown in Table 1. Comparative Example 2 Regarding the same hollow fiber bundle as in Example 1, 1, 1,
After washing by immersing it in a 1-trichloroethane bath, it was left to dry in an atmosphere of 70 to 80°C, and the same measurements as in Example 1 were performed, and the results shown in Table 1 were obtained. . Furthermore, an artificial kidney was prepared using this hollow fiber and a leak test similar to that in Example 1 was conducted, and the results were as shown in Table 1. Comparative Example 3 When the same measurements as in Example 1 were carried out without washing the hollow fibers used in Example 1, the results shown in Table 1 were obtained. In addition, after creating an artificial kidney using this hollow fiber and passing physiological saline through it, we conducted a leak test similar to that in Example 1.
It was as shown in the table.

[Table] Specific Effects of the Invention As described above, the present invention obtains hollow fiber bundles by cutting cellulose-based hollow fibers containing a non-coagulable liquid spun from a cellulose-based spinning dope, and The internal non-coagulable liquid is forcibly removed from one end of the bundle, and a cleaning solvent with high solubility and volatility in the internal non-coagulable liquid is forced to flow inside and outside the hollow fibers, and then the Since this is a method for producing hollow fibers for blood treatment, which is characterized by forcibly circulating gas inside and outside the hollow fibers,
Since it is possible to obtain a hollow fiber for blood treatment that not only has a sufficient cleaning effect on the inside of the hollow fiber but also has a sufficient cleaning effect on the outside, it is possible to obtain a hollow fiber for blood treatment that has a sufficient cleaning effect on the inside and outside of the hollow fiber. This has the advantage of significantly reducing leaks that often occur when used in artificial kidneys. Furthermore, since the outside of the hollow fiber is also forcibly cleaned, the non-coagulant liquid adhering to the outer surface of the fiber can also be removed. Since the comrades do not stick together, it is possible to obtain a hollow fiber for blood treatment that does not cause pinholes or blood leakage due to pinholes. In addition, the internal non-coagulable liquid can be forcibly removed by suction ventilation, forced ventilation, or by standing up the hollow fiber bundle and letting it flow down, which is an extremely simple method. can be minimized, increasing the cleaning effect of subsequent cleaning solvents. Furthermore, since the forced circulation of the cleaning solvent is carried out by suction or forced circulation of the cleaning solvent, excellent cleaning effects can be achieved with an extremely simple method. Further, the forced circulation of the cleaning solvent is carried out by centrifugal force or by immersing the hollow fiber bundle from the lower end and overflowing the cleaning solvent from the upper end, resulting in extremely excellent workability and productivity. Furthermore, if the internal non-coagulable liquid is forcibly removed and the cleaning solvent is forced to flow at the same time, productivity can be further improved. In addition, since the gas is forced to flow inside and outside the hollow fibers, the cleaning solvent can be dried quickly, and the pressure of the gas makes the hollow fibers more uniformly dispersed in the hollow fiber bundle. Hollow fibers for blood treatment that can be thoroughly cleaned without leaving behind cleaning solvents that adhere to dense areas that are difficult to clean, as well as internal non-coagulable liquid that comes out from the cut ends of the hollow fibers. can be obtained.

[Brief explanation of the drawing]

1 to 3 are schematic side views showing the process principle of the hollow fiber manufacturing method according to the present invention, FIG. 4 is a schematic partially cutaway side view showing another embodiment, and FIG. 5 is a schematic side view showing another embodiment. FIG. 6 is a perspective view with a partially cutaway view showing an example of an artificial kidney using hollow fibers according to the present invention. 1...Outer cylinder for cleaning, 2...Hollow fiber bundle, 3...
Suction cap, 4... Conduit, 5a, 5b, 5c...
... Suction device, 6... Cleaning solvent, 7... Gas supply device, 8... Rotating plate.

Claims (1)

[Claims] 1. A hollow fiber bundle containing a non-coagulable liquid spun from a cellulose-based spinning dope is cut to obtain a hollow fiber bundle, and the internal non-coagulable liquid is released from one end of the hollow fiber bundle. At the same time as forcibly removing the hollow fibers, a cleaning solvent having high solubility in the internal non-coagulable liquid and having high volatility is forcibly distributed inside and outside the hollow fibers, and then gas is forcibly introduced into the inside and outside of the hollow fibers. A method for producing hollow fibers for blood treatment, which comprises distributing them. 2. The method for producing a hollow fiber for blood treatment according to claim 1, wherein the forced removal of the internal non-coagulable liquid is carried out by discharging the internal non-coagulable liquid by suction ventilation or forced ventilation. 3. The method for producing hollow fibers for blood treatment according to claim 1, wherein the internal non-coagulable liquid is forcibly removed by standing up the hollow fiber bundle and letting it flow down. 4. The method for producing a hollow fiber for blood treatment according to any one of claims 1 to 3, wherein the forced circulation of the cleaning solvent is carried out by suction or forced circulation of the cleaning solvent. 5. In the hollow fiber for blood treatment according to any one of claims 1 to 3, the forced flow of the cleaning solvent is carried out by the flow of the cleaning solvent into and out of the hollow fiber by centrifugal force. Production method. 6. The forced circulation of the cleaning solvent is carried out by standing the hollow fiber bundle vertically on a horizontal surface, allowing the cleaning solvent to flow through the lower end, and overflowing the cleaning solvent from the upper end. A method for producing a hollow fiber for blood treatment according to any one of Items 1 to 3. 7. The method for producing a hollow fiber for blood treatment according to claim 6, wherein the forced removal of the internal non-coagulable liquid and the forced circulation of the cleaning solvent are performed at the same time. 8. The method for producing a hollow fiber for blood treatment according to any one of claims 1 to 7, wherein the forced gas flow is performed by suction flow or forced flow of the gas.