JPS5884007A - Hollow fibrous membrane for dialysis and its production - Google Patents

Abstract

PURPOSE:To obtain hollow fibrous membranes for dialysis of blood which can provide membrane performance without affected by the shapes of modules in said membranes by using hollow fibrous membranes wherein hollow fibers are in point contact with each other and the boundary film resistance on the membrane surface is decreased. CONSTITUTION:The cellulose ester hollow fibrous membranes for dialysis produced by semi-wet type or wet type spinning are immersed in an aq. glycerol soln. and are dried at 40-80 deg.C; thereafter the membranes are taken up on bobbins. The tension during taking up is preferably <=5g/single yarn and the average winding density is preferably 45-55%. The bobbins are treated under heating at the same temp. as the drying temp. upto a temp. higher by 20 deg.C to crimp and set the fibers. In order to assure the clearances among the fibers that serve as flow passages for dialyzate so as to obtain optimum efficiency of dialysis, it is necessary to provide 10-35 crimps in each 10cm of the hollow fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel hollow fiber membrane, and relates to a hollow fiber membrane for dialysis suitable for purifying body fluids by dialysis and its Mji method.

Cell p-suesters have traditionally been processed into hollow S1I fibers for energy-saving separation processes such as desalination of shrubs and seawater, ultrafiltration of aqueous solutions containing various solutes, etc. has been used for.

On the other hand, as a material for hollow wire membranes used for blood purification in patients with renal failure, cellular ester-based hollow MAHs have been extensively researched and developed due to their compatibility with living organisms and ease of manufacture. Necessary characteristics of the hollow #IA fibrous membrane used for hemodialysis include no blood leakage from the hollow m-pongee, wA element,
It can easily remove small molecular weight waste products from the body, such as uric acid and creatinine, and has balanced water permeability. But more importantly, the hollow fiber membrane is focused and blood processing device (module)
The aim is to fully demonstrate the performance of hollow fiber membranes when assembled. In parallel with the development of hollow fiber membranes, research has been carried out on the shape of mosieres, starting with a simple cylindrical shape, and developing shapes such as flat fields, three-chamber tubes, and knobby container types.

The present inventors have been diligently researching hollow fibers that can fully exhibit the performance of hollow fiber membranes, regardless of the shape of the mosier. The present inventors focused on the fact that the contact of the dialysate during hemodialysis with the outer surface of the hollow fibers and the performance of the hollow 18m membrane were closely related, and when observing the hollow fibers inside the module, they found that the hollow fibers were straight, In cell four-ester hollow fibers that do not have a crimp shape, the hollow fibers come into close contact with the adjacent hollow wires during dialysis, which seriously prevents the dialysate from coming into uniform contact with the outer surface of the hollow fibers, causing the dialysis vehicle to The present inventors have improved the line contact between hollow fibers during dialysis to point contact, and have found that the flow of dialysate is turbulent on the surface of the hollow fibers. We have discovered a hollow fiber membrane that reduces membrane resistance on the membrane surface.

That is, the gist of the present invention is that the outer diameter R (unit: Mitada) of the hollow fiber membrane for dialysis is within the range of formula (1), and the number of crimp n(10cIIl) of the hollow fiber is 111th place) is the (it) formula, and the crimp amplitude (unit It chron) is (it)
Hollow 1ml/IA specially forged to be within the range of O type
Membrane and goo≦R≦aoo (1) 10≦n≦s s (If) o, ssxm≦t≦m+no , immersed in an aqueous glycerin solution and then dried in air or inert gas at a temperature of Tlt),
It is then wound up and further consists of hot-embedding the wound material in T.1).

Cellulose esters that can be used in the hollow fiber membrane of the present invention include cell p-diacetate, cell p-striacetate, cell p-striacetate, cell p-bionate, and cell p-striacetate.
Zupetire F, seven ru p-acetate tapa bionate,
Cellulose esters such as cellulose acetate butyrate may be used alone or as a mixture thereof.The organic solvent for the cellulose ester used in the present invention may include dimethylformamide, methylpyrrolidone, dimethylacetamide, acetone, etc. In addition to cellulose ester and the above-mentioned organic solvent, a polyhydric alcohol is used as a third component in the spinning stock solution used. As the polyhydric alcohol, ethylene glycol, triethylene glycol, glycerin, polyethylene glycols of various molecular weights, etc. are used.

Talimp of the present invention! -The cellulose ester hollow fiber membrane is not affected by the layered structure of the mosier, maintains the barrier between the hollow fibers, and causes turbulence in the flow of dialysate on the linear surface, reducing the membrane resistance on the membrane surface. , thus obtaining an effective dialysis vehicle.

In order to obtain the optimum dialysis efficiency, in order to secure the gaps between the hollow fibers that serve as the flow path for the dialysate using hollow fibers with crimps, 10 or 3 s of crimps are required per 10 gm of hollow fibers. The crimp number in the present invention is 0, when the hollow fiber is viewed in the axial direction, so that one vertex of the hollow fiber and an adjacent diametrically opposing vertex become the vertex of the sim curve. The central axis in the axial direction of the hollow fiber is set, and the number of crimps is the number of crests on the same side with respect to the central axis of the hollow fiber LO. If the number of crimps is 9 or less, Hollow #
Unable to fully demonstrate the performance of IA fibers0
When the number of crimps exceeds s8, the perfect circular shape of the hollow I/IAIa tends to collapse, and there is a risk that it may cause blood stagnation during hemodialysis. The most preferable condition for the number of crimps in the hollow fibers is around 20.

In order to increase the efficiency of dialysis, not only the number of crimps but also the crimping amplitude L (ripple position I), which is an indication of the size of the crimps, plays a large role. The crimp amplitude in the present invention is:
The central vertex of the hollow fiber and then II! 1! is half the lateral distance between the hollow fibers of diametrically opposed vertices. If the crimp amplitude is smaller than 0.615XR, it is not possible to secure sufficient gaps between the hollow fibers during dialysis.
Hollow fibers tend to stick together, which further disrupts the flow of dialysate and reduces membrane resistance on the membrane surface.

Therefore, the performance of hollow fibers cannot be fully demonstrated. In the range where the crimp vibration exceeds i + a o, the convergence state becomes large when converging hollow fibers,
Uniform arrangement of hollow fibers becomes difficult when used as a module. These factors are factors that seriously reduce the dialysis efficiency during dialysis. It has been found that the optimum dialysis efficiency can be obtained when the hollow fiber has a contraction amplitude.The outer diameter of the hollow fiber can be selected within a wide range, but when considering a hollow fiber membrane for dialysis, it is from 200μ to WO.
Oμ is the membership fee.

The best way to spread cellulose ester hollow fibers having such crimps is to spin hollow fiber membranes using conventional semi-wet spinning and wet spinning, and then spin hollow fibers that have been given the performance as a dialysis membrane through various processes. immersed in a glycerin water bath solution,
It is then dried in air or inert gas at a temperature T, tl in the range from 40°C to 80°C and then wound onto a bobbin. Regarding the tension and winding density during winding, in the present invention, the tension is Bfl/single yarn or less, and the average winding density is 45~sep.
It is preferable to set it to . By heat-treating the wound bobbin at 71° C., the hollow fibers are crimped and the crimps are fixed. If the drying temperature is lower than 40°C, the moisture adhering to the hollow fibers after treatment with the glycerin aqueous solution cannot be sufficiently removed, and even heat treatment after winding up the bottle will not result in sufficiently long-lasting crimp. cannot be granted. When drying at a temperature higher than 80° C., the hollow fibers are fixed during drying, and sufficient crimp cannot be imparted by the Mebbin heat treatment.

Hollow 1 after heat treatment! It is desirable to adjust the moisture content in the fibrous membrane to about 10% or less.

In addition, as mentioned above, it is important to soak the hollow fiber membrane in a glycerin water bath before drying it to prevent the membrane performance from degrading over time. Even if drying and heat treatment are performed, the desired crimps cannot be imparted.Furthermore, in the present invention, the proportion of the above-mentioned crimped hollow fibers in the total fibers is at least 60%, preferably at least 60%. This is preferable, and a partially hydrolyzed cellulose ester hollow fiber membrane can also be included.

The crimpable hollow fiber membrane according to the present invention has good dialysis ability and provides sufficient dialysis efficiency even after assembly of the module, and its manufacturing method is based on bobbin heat treatment, and a simple device is used. You can easily make one.

Hereinafter, the present invention will be explained in more detail with reference to specific examples, but the present invention is not limited to the scope thereof.

In addition, the drift values described in the examples below are obtained as follows,
The smaller the drift value, the less stagnation of the dialysate and the better the dialysis efficiency of the membrane.OWhen blood and dialysate flow countercurrently, the clearance of solutes in the blood (0) is expressed by equation (1). .

8
(Seal) IT-ku 0・■ Qm a Qil here! Blood flow rate and dialysate flow rate (-
7w) Kg i Overall mass transfer coefficient (am/-)8
Low module membrane area (inner diameter reference) (-) Blood flow rate J
! OOj/kaku, dialysis flow rate 800j/m.

Each clearance o when m OOO-/*,
Measure e 01. On the other hand, using 01, from equation (4), K
o is calculated, and from equation (1), the dialysis flow rate It OOJ/-
Find the clearance Os when . The difference between this Ol and the actual measurement value 01 is defined as drift/value.

Ds*0. -01 (P/) Example L 30 parts by weight of cellulose diacetate-F, 49 parts by weight of dimethylformamide, 100 r of polyethylene glycol
t11 parts by weight was stirred and dissolved for aat+L hours to prepare a spinning dope. This spinning stock solution was left to stand at 8 s°C for a period of time to defoam. The spinning stock solution was supplied from the outer tube section, where spinning was performed using an annular orifice nozzle with an inner diameter of 0.6-1 and an outer tube diameter of 1 m. After filtering the liquid paraffin with a 0.415μ filter,
The hollow stock solution that came out of the annular orifice supplied to the inner tube was run through the air for 18 cm, then introduced into a coagulation tank, solidified, washed with water, and run for 6 seconds through a 6-wt sodium hydroxide aqueous solution. Then, it was passed through an acetic acid aqueous solution bath, a water washing bath, and then passed through a 40% glycerin water bath, and then passed through a hollow wire fiber in a countercurrent flow to the dry air through a 60° C. dry air zone, and was heated by a wine goo. Tension IP
/ Winded onto a bobbin under single yarn conditions. The obtained hollow wire fiber had a perfect circular shape, an inner diameter of 100 μm, a film thickness of 16 μm, and was a straight hollow wire fiber. Rolled up l-bottle at 60℃6
Heat treatment was performed in a hot air dryer for 18 hours. The obtained hollow wire fiber had an inner diameter of gooμ, an outer diameter of [lμ, a number of crimp of go, and a crimp amplitude of 170μ. The permeability coefficient of the obtained hollow wire fiber for urea is 8Bx l O'cs+/s@
It was a. Using this hollow fiber, a cylindrical membrane surface @91
1.1a and d modules were fabricated.

Clearance of urea in the module is determined by the dialysis flow rate of 150
At 0 m/-, we obtained 160 m/kaku (0,). Further, l·ow/ym (Os) was obtained at a dialysis flow rate of 1000 sj/sm. If this value is converted to a dialysis flow rate of 800 wd/m, is it l? □sj/m (Os), and the drift value am −
c was found to be a membrane with good dialysis efficiency, as l Od/wjn l.

Comparative Example L The urea permeability coefficient of the hollow fibers of the bobbin before heat treatment in Example 1 was 84XIO-1cm+/-.O. There was no crimp in this hollow wire fiber. Honhollow #Im
As in Example I, a cylindrical membrane surface III 1.
i A module of JS1/ was created. The clearance of urea in the module is 18 at a dialysis flow rate of aooaj/m.
5 dlml was obtained. Also, l'F5-/- was obtained at a dialysis flow rate of 9000 sJ/im. This value is the dialysis flow rate aoow7-
When converted to 11!4m/m, the drift value is 19-/-
It was found that the performance of the hollow fiber membrane was not fully exhibited.Example a: Same as in Example 2, dimethylformamide was replaced with violet-methylbisudone polyethylene glycol Hatake 00 was replaced with triethylene dalycol. A spinning stock solution was prepared using the system. The composition ratio and core liquid are the same as in Example 1. The dope and core liquid are extruded through the annular Oriace nozzle, passed through the air, guided into a coagulation tank, solidified, washed with water, passed through a weight arc F hydroxide water bath, and then passed through an acetic acid water bath. liquid bath,
Passed through a water washing bath, then passed through a 48 weight fly glycerin water bath, and then passed through a hollow IIi wire in countercurrent with a zone of dry air at StS°C, with wine goo at a tension of 8.6 g/single yarn condition. I rolled it up into a l bottle. The obtained 1-bottle was heat-treated in a hot air dryer at gs° C. for 18 hours. The obtained hollow fiber had an inner diameter aSSμ and an outer diameter of 816 mm.
μ, the number of crimps was 18, and the crimp amplitude was 1109 μ. Cylindrical membrane surface @l using this hollow fiber, 1. I created a module for d.

The urea clearance of the module is determined by the dialysis flow rate of 5oo-
7-, 181 dlm and dialysis flow rate ε00〇-/-
The value obtained by converting the value into a dialysis flow rate of 1500-/- was 16fjdl-, and it was found that the membrane had a good dialysis efficiency with a drift value of only ll&sj/k.

Comparative Example a A module with a circular film surface @ 1L111F was created from the hollow wire fiber of 1 bottle before being subjected to the heat treatment of Example B. ◎ This hollow lllAm had no crimp. The clearance of urea in Mosier is 118 at a dialysis flow rate of 5OOd~
dlm, and the value calculated from the dialysis flow rate of 2000 dlm to the dialysis flow rate l500-/III'I is:
15 B g&t/w, and the drift value is 37 d
It was found that the performance of the hollow fiber membrane was not fully demonstrated.

Comparative Example & When the hexaacetate hollow fibers spun and wound under the same conditions as in Example B were subjected to heat treatment conditions (SO°C) different from those in Example 8, there was no winding inside the cheese or in the hollow fibers. Shrinkage was occurring. The contraction number is 19dlITo 18
In 1807, Kusuke Kusuke created a module with a Heisan-type membrane area and weight of 1♂, using the Sakiji Shinku wrinkle repair in 1807.

Mosier's urea clearance is dialysis flow rate of 80'O
sj/m, 1JlosJ, - and the dialysis flow rate jloo
The pulp converted to dialysis flow rate δ00sJ/kaku from the value determined by os7/- is l1ls'/kaku, and the drift value is! I
@-/1111, and it was found that the performance of the hollow fiber membrane was not fully demonstrated @Patent applicant Toyo vj
Achievements Co., Ltd.

Claims (1)

[Claims] L In a hollow delicate membrane for dialysis, the outer diameter R of the hollow fiber (
If the unit + 1st point) is within the range of formula (1), and the crimping rate per loam (unit: ka pieces) of the Rinchuuken - is (if)
A hollow LA membrane for dialysis, characterized in that the crimp amplitude L (unit electric current) is within the range of the (iiD formula). too≦R≦s o o (1) 10≦n
≦s s (1) 0.6BxR≦L≦1
A 10-m cell four-ester hollow fiber membrane was spun, immersed in a glycerin water bath, and then heated to ℃
A method for manufacturing a hollow fiber membrane for dialysis, which is characterized by drying in air or inert gas, then winding, and further heat-treating the roll in 'r, tr. T8, 78℃ is Qψ
, (V) Temperature 40≦T, ≦80 (IV) TI≦T
Snow ≦ i + * o (V)