JPS6065107A - Production of hollow fiber - Google Patents

Abstract

PURPOSE:To manufacture an easily driable hollow fiber for dialysis, without necessitating the washing process, by passing a spinning dope successively through a non-coagulating liquid and a coagulating liquid, washing with water, and drying at a specific temperature by high-frequency heating. CONSTITUTION:Preferably, a spinning dope such as regenerated cellulose dope is extruded through an annular nozzle, and at the same time, a chlorofluorinated hydrocarbon (preferably 1,1,2-trichloro-1,2,2-trifluoroethane, etc.) is introduced through the pipe 7 to the center of the dope as a non-coagulating liquid 3. The linear spinning dope 8 extruded in a tubular form and containing the non-coagulating liquid as a core is passed through a non-coagulating liquid 3 and then through a coagulating liquid 4 to effect the coagulation of the dope and form a hollow fiber 12. The hollow fiber 12 is washed with water by the washing apparatuses 15, 17, and dried by a high-frequency heating in an atmosphere having lower temperature than the boiling point of the non-coagulating liquid to obtain the objective hollow fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION 10. Background Technical Field of the Invention The present invention relates to a method for producing hollow fibers. More specifically, the present invention relates to a method for manufacturing hollow Ill for dialysis, which does not require a cleaning process inside the hollow fibers and is easy to dry.

Prior Art Hollow fibers conventionally used for dialysis treatment of blood and the like include cellulosic substances such as regenerated cellulose and cellulose acetate, polysulfone, polyacrylonitrile, and BoIJ methyl methacrylate.

Among these, those currently in practical use are mainly regenerated cellulose made from cuprammonium cellulose.
These are excellent because they have a sufficiently strong surface 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.

Conventionally, hollow lIi navy blue extrudes cellulose-based spinning dope into the air or non-coagulable liquid through an annular spinning hole, and at this time, a non-coagulable liquid (internal liquid) for the spinning dope is extruded into the center of the linear spinning dope. It is introduced, filled and discharged, and then the linear spinning stock solution formed in this way is passed through to solidify and regenerate.
After washing, if necessary, glycerin treatment is performed to prevent the dialysis ability from decreasing, and further drying is performed (Japanese Patent Publication No. 53-30,808;
No. 199, 808, etc.).

Conventionally, the following methods have been considered as drying methods.

(a) Tunnel straight running drying (b) Chain conveyor type tunnel drying (C) Roller drying However, in the method (a) above, the hollow I for dialysis
A long device is required to obtain an appropriate moisture content for Ia fibers, and as the device becomes longer, it becomes difficult to control the tension. Furthermore, in the method (b) above, it is difficult to control the tension of the running fibers using conventional methods. In addition, above (
In method C,), rollers of the same diameter are arranged at equal intervals and the hollow fibers are stretched between the cough rollers for drying, so as drying progresses, the moisture content changes depending on the running position of the hollow fibers. Therefore, the tension of the hollow fibers becomes high.

If dried under such a relatively high tension state, an artificial kidney manufactured using the hollow SLI fibers has the disadvantage that the hollow fibers contract during autoclave sterilization, causing residual blood and a decrease in dialysis performance. For this reason, the dialysis hollow [I
However, methods that cannot control tension were inappropriate.

In addition, since all of the above drying methods selectively evaporate water, when spinning hollow fibers, a liquid with a higher boiling point than water, such as isopropyl myristate, is used as the internal liquid for forming hollow fibers. was.

Furthermore, since the hollow fibers are heated to high temperatures, although temporarily, there is a risk of deterioration.

Here, the internal liquid such as isopropyl myristate contained in the hollow fiber is considered to be harmful to the human body, so when using it for hollow fibers for hemodialysis, etc.
Must be cleaned and removed before use.

The cleaning method for removing the internal liquid of such hollow fibers is as follows:
(1) A method in which a chlorofluorinated hydrocarbon or a mixture of it and a substance that can form an azeotrope is distributed inside the hollow fiber (Japanese Patent Publication No. 56-22,541 and Japanese Patent Application Laid-Open No. 54-1989)
-160,099), (2) A method in which the hollow fiber bundle is washed with a low-boiling organic solvent and then dried, and then the ends of the hollow fiber bundle are fixed to a case (Japanese Patent Laid-Open No. 54-58, 68).
No. 7), (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 potting portions are cut to open, in which centrifugal force is applied in the length direction of the bundle. Method of making
No.), (4) 4- A method in which both ends of a hollow fiber bundle are fixed with a botting material, the fixed parts are cut to open both ends, and in this state lower alcohol is passed through to clean the bundle. -12,
No. 043) etc. have been proposed.

However, methods (1) and (2) use chlorofluorinated hydrocarbons and are therefore extremely expensive. Also, (4
) method uses lower alcohol as a cleaning solvent, so it has extremely high solubility in glycerin, and therefore the glycerin contained in the hollow fibers as a plasticizer is eluted, so the glycerin content of the hollow fibers is low.
Moreover, there is a drawback that the amount of residual cleaning solvent is large. In addition, in methods (1) and (2), about 25% of glycerin was sometimes lost due to physical action before washing. In addition, if washing is not performed sufficiently, botting failure may occur due to contamination due to internal fluid seeping out from the cut opening, and therefore, when used in an artificial kidney, blood often leaks. Furthermore, since the method (3) removes the internal liquid only by centrifugal force, its effectiveness is insufficient. Furthermore, (1) to 4) all required a step of removing internal liquid such as isopropyl myristate.

(1) Objective of the Invention Therefore, an objective 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 for dialysis that does not require a cleaning step inside the hollow fibers and is easy to dry.

The purpose of these developments is to discharge the spinning stock solution from an annular spinning hole, simultaneously introduce and fill the center of the interior with chlorinated fluorohydrocarbons as a non-coagulable liquid, and then pass through the coagulable liquid to solidify it. This is achieved by a method for producing hollow chicks, which is characterized in that the hollow chicks thus obtained are washed with water and then dried by high-frequency heating in an atmosphere at a temperature lower than the boiling point of the non-coagulable liquid.

Further, the present invention is a method for producing hollow fibers, wherein the spinning dope is a regenerated cellulose-based spinning dope. Furthermore, the present invention is a method for producing hollow fibers in which the regenerated cellulose-based spinning dope is a cuprammonium cellulose solution. The present invention provides that chlorofluorinated hydrocarbons are 1,1,2-trichloro-1,2,21
- A method for producing a hollow mm made of at least one member selected from the group consisting of refluoroethane, trichlorofluoromethane, dichlorofluoromethane, and 1,1,2.2-tetrachloro-1,2-difluoroethane. . In addition, the present invention provides high frequency heating of 400kHz to 400kHz.
This is a hollow fiber manufacturing method carried out at 50 MHz (0 frequency).

■1 Detailed Description of the Invention Hollow fibers produced by the present invention include cellulose ammonium such as copper ammonia cellulose and cellulose acetate;
There are synthetic uAN such as stereocomplex of polymethyl methacrylate, polyacrylonitrile, and ethylene-vinyl alcohol copolymer, but cellulose-based 1ft is preferable.

Especially cuprammonium cellulose. Although various types of cellulose can be used, for example, those having an average degree of polymerization of 500 to 2,500 are preferably used. Thus, the cuprammonium 7-cellulose solution is prepared by a conventional method. For example, first, aqueous ammonia, a basic aqueous copper sulfate solution, and water are mixed to prepare an ammonia aqueous solution, an antioxidant (e.g., sodium sulfite) is added to this, and then raw material cellulose is added and dissolved with stirring. An aqueous sodium hydroxide solution is added to completely dissolve undissolved cellulose to obtain a cuprammonium cellulose solution. This cuprammonium cellulose solution may further be mixed with a permeation performance controlling agent for coordination bonding.

There are various spinning methods, such as the aerial drop method, Japanese Patent Application Laid-Open Nos. 57-71,408 and 57-71.
410, a method for discharging into a non-coagulable liquid and then passing through an interface between the non-coagulable liquid layer and a coagulable liquid, JP-A No. 5
7-71,409, a method of discharging directly into a non-coagulable liquid and then passing a coagulable liquid through the liquid, JP-A-57-1999
71,411, a method of surrounding and discharging a non-coagulable liquid and then coagulating and regenerating it, JP-A-57-99,808
The coagulable liquid described in No. 1 is directly discharged from an annular spinning hole into the non-coagulable liquid of a bath liquid in which the upper layer is filled with a non-coagulable liquid made of a halogenated hydrocarbon in the lower layer,
At the same time, a non-coagulable liquid is introduced and filled into the center of the interior, and then,
There are methods of coagulating and regenerating by passing through a coagulable liquid (hereinafter referred to as flotation method), but the last flotation method is particularly preferable, so using this as an example, the present invention will be explained below with reference to the drawings. explain.

FIG. 1 is a side view schematically showing an entire apparatus for producing hollow fibers using the method and apparatus according to the present invention. That is, in a bathtub 2 having a non-coagulable liquid tank 1 at the bottom, a non-coagulable liquid 3 made of a halogenated hydrocarbon and corresponding to the cellulose-based spinning dope is added to the non-coagulable liquid tank 1 as a lower layer, and a non-coagulable liquid 3 is added as an upper layer to the non-coagulable liquid tank 1. A bath liquid consisting of two layers is formed by supplying a coagulating liquid 4 having a smaller specific gravity than the non-coagulable liquid and relative to the spinning stock solution. The spinning dope is pumped through the conduit 5 and directly extruded into the non-coagulable liquid in the lower layer through an annular spinning hole (not shown) provided upward in the spinneret w6. At this time, chlorinated fluorohydrocarbons, which are non-coagulable liquids for the spinning dope, are introduced into the spinneret device through a conduit 7 as an internal liquid, and the linear spinning dope 8 is extruded in a circular shape.
is introduced into the center of the interior and discharged. The linear spinning dope moves upward in the non-coagulating solution 3 due to the difference in specific gravity. Next, the hollow fibers are changed in direction by the change-of-direction rod 9 to pass through the coagulable liquid 4, and then pulled up by the rollers 10, and the hollow fibers are further subjected to a coagulation process and a water washing process by known means.

Such hollow fibers 12 are washed in an alkaline washing device 14, a first water washing device 15, an acid washing device 16, and a second water washing device 1.
7, re-solidify, wash with water, decopper, and wash with water. Then, after passing through a glycerin liquid 21, it is introduced into a dryer 22 and dried.

As shown in FIG. 2, the drying device 22 includes a plurality of rollers 41a, 41b...
...41n are arranged in series in a staggered manner from the inlet 38 to the outlet 39. This roller is driven and rotated at a predetermined speed by being connected to a driving means such as a motor (not shown) or a motor connected to a transmission, and to a transmission means such as a chain and a sprocket. This dryer main body 40 includes at least one high frequency generator (frequency 4
00kHz ~ 50MHz, preferably 800kHz
z~30Ml-1z) 42a and 42b form a vignetting high frequency heating area A. Further, if necessary, a drying area B is provided adjacent to the high frequency heating area A.

In addition, if the drying effect is insufficient with one high frequency generator 42a, 42b, another high frequency generator 43a may be used.
, 43b, 44a, 44b are provided to form high frequency heating areas C, E, etc., and drying areas, F, etc. are provided adjacent to the high frequency heating areas C, E, etc., respectively. This drying 11i
B, D, and F are inlet pipes 45 with dry air sources (not shown).
a, 45b and discharge pipes 46a, 46b are connected. Note that not only one row of each roller but also a plurality of rows can be provided in parallel, thereby increasing production capacity.

To carry out drying using such a drying device 22, first, a hollow fiber [t12 is introduced from the hollow fiber inlet 3 days and the fibers are dried between each O-ra 41a, 41b, 41C-11-..., 410. The fibers are successively stretched and passed through the drying device 22, and finally taken out from the hollow fiber outlet 39 and wound up.

Therefore, when the hollow fiber 12 is exposed to high frequency waves in the high frequency heating area A, since the chlorofluorinated hydrocarbons as the internal liquid are non-polar or low polar, the hollow fibers 12 hardly generate heat due to the high frequency waves. The water and glycerin (less calorific than water) contained therein generate heat due to high frequency waves, which is stored as latent heat of vaporization. Next, the hollow lJm having the latent heat of vaporization stored in this way is in the drying area B at a relative humidity of 0.
05 or less, preferably 0.03 or less, more preferably 0.01, and evaporates moisture by contacting with dry air at a temperature lower than the boiling point of the internal liquid, and the evaporated moisture is discharged from the discharge pipe 46b. Since the glycerin contained in the hollow 1/aM has a high boiling point, it does not evaporate. The latent heat of vaporization is 539 cal per gram of water at 100°C, and the amount of heating required from 25°C to 100°C is 75 cal, totaling 614 cal.
- Although it is necessary, the latent heat of vaporization at a temperature of 25℃ is 582ca
1, and since no heating is required, drying at a low temperature requires 26 ca+ less heat.

When drying at this low temperature, the temperature of the hollow fiber does not increase while water evaporates (equilibrium state). Therefore, the chlorinated fluorinated hydrocarbons, which are the internal liquid, do not rise to their boiling point temperature and are surrounded by glycerin, so vaporization and transpiration of the chlorinated fluorinated hydrocarbons do not occur, and the hollow fiber shape is maintained. Similarly, by sequentially repeating high frequency heating in high frequency heating zones C and E, drying zone and drying in F, hollow fibers with a predetermined degree of dryness can be obtained. Further, as the water content in the hollow fibers decreases, the latent heat of vaporization is reduced, so it is desirable to perform high frequency heating intermittently to control the temperature of the hollow fibers. Moreover, high frequency heating may be performed in a dry area. In addition, the running speed of the hollow m-thickness is 40~
130m/sin.

Preferably it is 45 to 100 m/1n. Moreover, one hollow fiber may be stretched over each roller, but a plurality of hollow fibers, for example, three hollow fibers may be stretched across each roller.

Next, the present invention will be explained in more detail by giving Examples. In addition, in the following examples, all percentages are by weight unless otherwise specified.

Example 2 A cupric ammonia aqueous solution was prepared by suspending 540 o of basic copper sulfate in 2,354 (J) of a 5% aqueous ammonia solution, and 1.690 (J) of a 10% aqueous sodium sulfite solution was added to this solution. 1°000 (±100) cotton linter pulp was wet-pulverized and dehydrated water-containing linter (moisture content 69°7%) 2.2730 was added.
! Add 210 g of RO water for temperature adjustment and dissolve with stirring, then 1,233 g of 10% sodium hydroxide aqueous solution (+
to prepare a cuprammonium cellulose aqueous solution (specific gravity 1.0
8) was adjusted to prepare a spinning dope.

On the other hand, using an apparatus as shown in FIG. A lower layer was formed by supplying the spinning dope, and then an aqueous sodium hydroxide solution with a concentration of 50(]/2 was supplied as a coagulating liquid to form an upper layer.The spinning stock solution was passed through a spinneret device equipped with an annular spinning hole facing upward. 6, and was directly discharged from the spinning hole into the non-coagulating liquid 3 in the lower layer at a liquid temperature of 20±2° C. under a nitrogen pressure of 5 ka/an2.The diameter of the spinning hole was 3.8 mm, and the spinning dope was (ce, 217°8%, 1.1001) (20°C))
The discharge rate was 5°86 nλ/min. On the other hand, trichlorofluoromethane (specific gravity 1.466) was introduced from the non-coagulable liquid introduction tube 7 attached to the spinneret device 6, and was included in the linear discharge stock solution and discharged. Diameter of the introduction tube. is 1
．． 21, and the discharge amount of trichlorofluoromethane is 1
．． The rate was set at 50 IIll/min. Next, the discharge stock solution (containing non-coagulable liquid) 8 (specific gravity 1.026) was mixed with 1. ．． 1, 2-Trichloro-1,2,2-trifluoroethane, and then the upper layer of sodium hydroxide aqueous solution (20 ± 2 ° C.
) After pulling up the inside, it was made to run in the horizontal direction using the change-of-direction rod 9. At this time, the layer height of the non-coagulable liquid was 200 mm, the distance from the interface to the upper end of the deflection rod 9 was 150 mm, the spinning speed was 60 II/min, and the traverse wind was 80 mm.
The mileage per mile was 15-11f4.4+11. Roller 10 from this bathtub
After pulling it up, it was sufficiently coagulated with a 12% aqueous sodium hydroxide solution using a known method, and washed with water.
% sulfuric acid (decopper removal treatment), and further washed with water.

Next, in the plasticizing process, the hollow fibers are placed in a glycerin aqueous solution with a concentration of 1.8% by weight and kept at a temperature of 55 to 60°C.
Running speed before plasticization: 51 to 52 I/1n1 Running speed after plasticizing: 54n+/main 1 The stretching ratio based on the running speed before and after plasticization was set to 1.05, and the film was immersed for 4.5 seconds to run. Then, it was heated in a drying device 22 using a high frequency of 10 MHz, and dried using air at 30° C. and a relative humidity of 0.01.

The hollow fibers thus obtained were cut to a length of 26C11, and 10,000 fibers were bundled to obtain a 411wIt hollow bundle filled in a polypropylene outer cylinder. A suction device was activated to blow hot air at 70 to 80° C. through the hollow fiber bundle for 5 minutes to remove the internal liquid. The measurement results of the glycerin content in the hollow fibers and the residual internal liquid 16- were as shown in Table 1. Note that the glycerin content was 6.72% before internal removal.

Comparative Example 1 In the same manner as in Example 1, isopropyl myristate was used instead of trichlorofluoromethane, roller drying was used as the drying method, and Fronsolve (CCj & 2F-CCj!F) was used as the cleaning liquid inside the hollow fibers.
Hollow fibers were produced in the same manner, except that the product (trade name, manufactured by XI Glass Co., Ltd.) was used, and the same measurements were carried out.
When the residual detergent was measured, the results shown in Table 1 were obtained.

Comparative Example 2 In the same manner as in Example 1, isopropyl myristate was used instead of trichlorofluoromethane, roller drying was used, and Tsurmix AP-1 (ethanol 85.6
%, methanol 1°1%, and isopropanol 13
．． Hollow fibers were manufactured in the same manner except that 3% (product name manufactured by Nippon Alcohol Sales Co., Ltd.) was used, and the same measurements were carried out. Furthermore, the residual cleaning solvent was measured, and the results shown in Table 1 were obtained. Obtained.

The tests for each item were conducted as follows.

, Sample preparation method for analysis.

The hollow fiber was cut into about 0.5 InI11 pieces with a cutter, about 1 g was put into a volumetric flask, and after refluxing in ethanol for 30 minutes, the fiber was diluted to a volumetric flask of 10 + al. This is used as a sample of residual internal liquid volume and residual glycerin.

As for the sample for residual solvent measurement, about 1 g of cut hollow fiber was accurately weighed, placed in a headspace bottle, and heated and vaporized in a water bath at 80°C.

Analysis method (1) Glycerin content colorimetric analysis - Acetylacetone method (triglyceride test Wako, manufactured by Wako Pure Chemical Industries) (2) Residual internal liquid gas chromatography analysis (using Hitachi model 163) - Gas chromatography conditions (i) Column 5E303% 2mx3+u T, D
.

(ii) Toumaro column 180°C.

Injection 200℃ (iii) Carrier gas N2 40mj! /w+
1n (3) Residual cleaning solvent Gas chromatography analysis 0 Gas chromatography conditions (+) Column PEG20M 2mx3mm 1. D
.

(ii) Temperature column: 100°C.

Injection 120℃ (iii) Carrier gas N2 40mj! /m1
n0 Headspace Bottle/Method 19- Glycerin Residual internal liquid Residual cleaning solvent ('') Content (
%) (ppm) -1 肚w+) Example 16.25
0 - Comparative Example 1 5.05 112.4 0 Comparative Example 2 0.1 19.6 338 (The following is a blank space) 20- ■1 Specific effects of the invention As described above, the method for producing hollow fibers according to the present invention The spinning stock solution is discharged from the annular spinning hole, and at the same time, chlorinated fluorohydrocarbons are introduced and filled into the center of the interior as a non-coagulable liquid, and then passed through a coagulable liquid to solidify. After washing the hollow fibers with water, they are dried by high-frequency heating in an atmosphere at a temperature lower than the boiling point of the chlorofluorohydrocarbons, so the chlorofluorohydrocarbons that are the internal liquid are nonpolar or low polar. Therefore, almost no heat is generated by high frequency waves, and only the water contained in the hollow fiber generates heat and is stored as latent heat of vaporization. When this comes into contact with air, the water evaporates, but during this time, the hollow l/l/ The temperature of the miscellaneous material does not rise, and therefore the chlorinated fluorinated hydrocarbons do not rise to their boiling point moisture content, and the shape of the hollow 111 is maintained. In addition, since the internal liquid is a chlorinated fluorinated hydrocarbon, it does not dissolve the glycerin contained in the hollow fibers, and since it does not use isopropyl myristate, etc. as in the past, cleaning is virtually unnecessary. becomes.

Further, when a regenerated cellulose-based spinning dope, particularly a cuprammonium cellulose solution, is used as the spinning dope, it is extremely advantageous because there is substantially no dissolution of the glycerin used for plasticizing the dope. Furthermore, as chlorofluorinated hydrocarbons, 1,1,2-1-lichloro-1,2,2-trifluoroethane, trichlorofluoromethane, dichlorofluoromethane, and 1,1,2,2-tetrachloro-1
, 2-difluoromethane, the boiling point is lower than that of water, so there will be less residue and less impact on the human body, making it extremely effective as an internal liquid. In addition, the conventional cleaning process after drying can be omitted, and cleaning equipment, cleaning agents, and maintenance costs for the cleaning process are unnecessary, making it extremely economical. This makes it possible to obtain hollow fibers that are as good as, if not better than. Furthermore, if high frequency heating is performed at 400 kHz to 50 MH1, the heating effect will be moderate.

[Brief explanation of the drawing]

FIG. 1 shows a hollow I! using the method according to the invention! 2 is a side view schematically showing the entire apparatus for producing a
The figure is an enlarged sectional view of a drying device used in the method of the present invention. 12... Hollow IItIi, 14... Alkaline cleaning device, 15.17... Water washing device, 16... Acid cleaning device, 21... Glycerin aqueous solution, 22... Drying device,
41a, 41b, 41c, 41d--...-4'
In--drive rollers, 42a, 42b, 43a, 43b, 44a,
44b...High frequency generator.

Claims (5)

[Claims] (1) The spinning dope is discharged from the annular spinning hole, and at the same time, chlorinated fluorohydrocarbons are introduced and filled into the center of the interior as a non-coagulating liquid, and then passed through the coagulating liquid to solidify. A method for producing hollow II fibers, which comprises washing the obtained hollow fibers with water and then drying them by high-frequency heating in an atmosphere at a temperature lower than the boiling point of the non-coagulable liquid. (2) The method for producing hollow fibers according to claim 1, wherein the spinning dope is a regenerated cellulose-based spinning dope. (3) The method for producing hollow fibers according to claim 2, wherein the regenerated cellulose-based spinning dope is a cuprammonium cellulose solution. (4) Chlorinated fluorinated hydrocarbons are 1.1.2-trichloro-
1,2,2-trifluoroethane, trichlorofluoromethane, dichlorofluoromethane, and 1,1.2.
The method for producing a hollow fiber according to any one of claims 1 to 3, wherein the hollow fiber is at least one selected from the group consisting of 2-tetrachloro-1,2-difluoroethane. (5) High frequency heating is 400kHz to 50MHz (
A method for producing a hollow fiber according to claim 1, which is carried out at frequency D.