JPS61266609A - Modified cross-section hollow fiber, modified cross-section hollow fiber bundle and fluid separator - Google Patents

Abstract

PURPOSE:To obtain a fluid separator having excellent separation efficiency in the fluid separation of blood, etc., by filling modified cross-section hollow fiber provided with plural rows of fins having various fin heights and distances between the fins along the circumference of the fiber. CONSTITUTION:A selective-permeable modified cross-section hollow fiber provided with longitudinal fins, wherein the average heights of the fins are essentially different from each other and/or the distance between adjacent rows are essentially different, are filled in a container. The fins are effective to prevent the contact of the fibers even at a high packing density. A local clustering of the fibers can be prevented and an excellent flow characteristic can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention provides a permselective finned irregularly shaped hollow fiber, a finned irregularly shaped hollow fiber bundle, and a fluid separator containing at least one of these. More detailsF
The present invention relates to irregularly shaped hollow fibers with fins, a hollow fiber bundle, and a fluid separator containing the same, characterized in that the fins are narrow and the distances between the fins are not substantially the same.

[Prior art]

Conventionally, hemodialyzers have been used to purify the blood of renal failure patients and remove excess water. In this system, a large number of dialysis membranes, such as hollow fiber membranes, are housed in a container, and the patient's blood is poured into the hollow interior of the container, and the dialysate is poured outside, that is, between the hollow fiber membranes, and the blood is dialyzed through the hollow fiber membranes. It removes waste products from the blood, adjusts the electrolyte concentration, applies a pressure difference between the inside and outside of the hollow fiber membrane, and removes excess water from the blood through ultrafiltration. In addition, a method (blood filtration) in which a large amount of water and waste products are removed only by ultrafiltration and the excess water is replenished together with necessary components such as electrolytes (blood filtration) is applied depending on the actual situation. Furthermore, clinical trials have also been made to use hollow fiber membranes to separate plasma from blood or remove specific harmful components from the plasma to treat autoimmune diseases.

Conventionally, various efforts have been made to improve the dialysis performance, which is the most important performance of a dialyzer. However, it cannot be said that the problem of uneven flow of dialysate due to close contact between hollow fibers in a dialyzer has been sufficiently solved. Examples of solutions to date include increasing the amount of hollow fibers stored in the dialyzer container (filling rate) to some extent, or crossing hollow fibers to create more resistance to dialysate flow than traps, resulting in a more uniform flow. An attempt was made to make this possible. Furthermore, by crimping the hollow fibers or wrapping a cover yarn around the hollow fibers, the hollow fibers are prevented from adhering to each other. The efficiency of mass transfer through liquid flow has been improved. However, these solutions are still not sufficient, and further improvements are desired.

Purpose of the Invention The purpose of the present invention is to solve these problems and provide a hollow fiber membrane or a hollow fiber bundle with excellent separation efficiency in fluid separation such as blood treatment, and a fluid separator filled with the hollow fiber membrane or hollow fiber bundle. It is said that In particular, the object is to obtain a hollow fiber or a hollow fiber bundle in which the filling state in a fluid separator is likely to be uniform, and even when the packing density is increased, it is extremely difficult for the hollow fibers to adhere to each other.

[Structure of the invention]

The present inventors conducted extensive research to achieve this objective, and found that irregularly shaped hollow fibers having multiple fins are preferable, and in particular, it is preferable to use irregularly shaped hollow fibers with different fin heights and circumferential distances between the fins. The inventors have discovered that this is effective and have arrived at the present invention.

That is, the present invention provides a selectively permeable modified hollow fiber having a plurality of fins extending in the longitudinal direction at the outer periphery, in which the average height of each fin is substantially different and/or the average height of each fin is substantially different from that of the adjacent fins. Irregularly shaped hollow fibers characterized in that the distance between the two threads is substantially different; A bundle of irregularly shaped hollow fibers attached via fins, in which the average height of each fin strip other than that required for attachment is substantially different, and/or the distance between two adjacent strips is substantially different. In a fluid separator containing irregularly shaped hollow fiber bundles characterized by being non-identical; and permselective hollow fibers, (1
) having a plurality of longitudinally extending fins in the external private part, the average height of each of the fins being substantially different; and/
or (2) a permselective irregularly shaped hollow fiber in which the distance between two adjacent threads is substantially different; and/or (2) a permselectively irregularly shaped hollow fiber having three or more fins extending in the longitudinal direction on the outer periphery. An irregularly shaped hollow in which a plurality of fins are attached via the fins, and the average heights of the fins other than those required for attachment are substantially different and/or the distances between two adjacent fins are substantially different. The present invention provides a fluid separator characterized in that a yarn bundle is housed therein.

The present invention will be explained in more detail below.

The irregularly shaped hollow fiber in the present invention has a plurality of fins extending in the longitudinal direction on its outer periphery, and the average height of each fin is not the same, or the distance between two adjacent fins is not the same. are not the same, or both the height and the distance between two adjacent strips are different.

That is, it is preferable to use irregularly shaped hollow fibers in which the average height of the highest fin among the plurality of fins is 1.5 to 10 times the average height of the lowest fin, and especially when the magnification is 2 to 5, In its filled state, close contact between hollow fibers is difficult to occur,
In addition, sealed spaces between the fins or between the fins and the hollow fiber wall are less likely to occur, and the fluid on the outside of the hollow fibers can more easily flow.

Further, it is preferable that the maximum value of the distance between two adjacent fins for a plurality of fins is 1.5 to 10 times the minimum value, and the distance between two adjacent fins is 2 to 5 times the minimum value. If it falls within this range, in a fluid separator filled with the hollow fibers, it is difficult for the hollow fibers to come into close contact or to create a sealed space between the fins or between the fins and the hollow fiber wall, and the fluid flow outside the hollow fiber wall. The properties are very good. Note that the circumferential distance between the threads refers to the shortest distance along the circumference of the hollow fiber outer wall between the centers of two adjacent fins.

The fin number line of the hollow fiber of the present invention is preferably 2 to 10,
Particularly preferred are 3 to 8 strips. In addition, when there are three or more fins, it is preferable that the number of high fins is relatively small, such as one or two fins, because the fins can create a sealed space. If the number of fins is 11 or more, it is not practical because the decrease in membrane performance at the base of the fins becomes relatively large.

In addition, it is most preferable for the hollow fibers of the present invention to satisfy not only the difference in fin height but also the difference in the distance between two adjacent threads, but it is relatively easy to make only the fin heights different. The effect can be obtained.

The irregularly shaped hollow fiber bundle referred to in the present invention is one in which a plurality of selectively permeable irregularly shaped hollow fibers having three or more fins are attached via the fins, and the bundle has a shape that is The invention is characterized in that the heights of the plurality of fins having free ends other than the fins are substantially unequal, and/or that the heights of all the fins are unequal between two adjacent fins.

Further, the irregularly shaped hollow fiber bundle preferably has 2 to 10 selectively permeable irregularly shaped hollow fibers each having three or more fins, each of which is attached via a fin. As for the form of attachment, it is necessary that a closed space surrounded by the hollow fibers is difficult to form, and it is desirable that the cross-sectional shape of the nine bundles of hollow fibers in the axial direction and the vertical direction is chain-like. . A hollow fiber bundle having 2 to 4, especially 2 irregularly shaped hollow fibers attached is preferable in that it is difficult to form a closed space. The number of fins in each irregularly shaped hollow fiber constituting the fiber is preferably 3 to 10, particularly preferably 4 to 8.

In the irregularly shaped hollow fiber bundle of the present invention, the highest point among the fins having a plurality of free ends.

1 of the average height of the lowest fin.
The ratio is preferably 5 to 10 times, and especially 2 to 5 times, the effect that a closed space is less likely to occur during filling can be easily obtained. Furthermore, for all fins including the fins required for attachment, the maximum value of the distance between two adjacent east is 1.5 to 1 of the minimum value.
0 times is preferable, and 2 to 5 times is more preferable.

It is most preferable that the hollow fiber bundle satisfies both the differences in the height of the fins and the differences in the distance between two adjacent threads.
Even if the fin heights are not uniform, it is difficult to form a sealed structure and the flow state on the outside of the hollow fibers is good. Further, it is particularly preferable that one high fin having a free end is provided on each side of the irregularly shaped hollow fibers near the center forming the hollow fiber bundle.

Incidentally, the outer diameter and thickness of the hollow fibers, the shape, height, thickness, material, etc. of the hollow fibers in the irregularly shaped hollow fibers and irregularly shaped hollow fiber bundles of the present invention are not particularly limited. Practically, the outer diameter of the hollow fiber is 100 to 400μ, more preferably 200 to 3μ.
00μ is preferable, and the film thickness of the portion without the fin portion is preferably 5 to 50μ, more preferably 5 to 30μ. In addition, the height of the fin is 5 to 200μ, more preferably 10 to 100μ.
The thickness at the base of the fin is preferably in the range of 10 to 50μ, and the shape of the fin is such that the thickness at the base of the fin is about the same as the thickness at the middle of the fin. A thinner material is preferable because it reduces the reduction in effective membrane area.

The material for the hollow fiber membrane that is the object of the present invention may be any material as long as it can be formed into a permselective hollow fiber membrane. , polyacrylonitrile, polycarbonate, polymethyl methacrylate, polyolefin, polysulfone, polyethersulfone, etc., and copolymers containing these.

Examples include mixtures with other substances.

In order to produce irregularly shaped hollow fibers or irregularly shaped hollow fiber bundles, the fins according to the present invention require a spinning dope (melt or solution) for hollow fiber membranes.
is extruded into a gas or spinning bath through the double annular slit of a spinneret according to a conventional method, and the hollow part is filled with a gas or liquid that does not substantially react with or dissolve the membrane material. A method of spinning while holding the fiber is preferred. For example, a plasticizer such as polyethylene glycol is added to cellulose cyatate, it is melted and extruded into the air through a double annular slit in a spinneret, nitrogen gas is injected into the center, and the material is spun into hollow fibers. Plasticizers and the like are removed from the hollow fibers, and if necessary, they are saponified with alkali to produce hollow fiber membranes for blood treatment. In this case, in order to obtain a thick hollow fiber with fins according to the present invention as a spinneret for extruding the melt of the membrane material, a plurality of notches with different lengths and/or different distances between adjacent ones are formed on the outer periphery of the double ring part. It is preferred to use a spinneret with a

Further, in order to obtain the irregularly shaped hollow fiber bundle of the present invention, it is preferable to use the above.

Next, the fluid separator of the present invention will be explained. That is, the fluid separator is characterized in that it houses a large number of irregularly shaped hollow fibers and/or irregularly shaped hollow fiber bundles as described above. In some cases, other hollow fibers, such as permselective hollow fibers having a normal circular cross-sectional shape, may also be housed.

In such a fluid separator, a large number of these irregularly shaped hollow fibers or bundles of irregularly shaped hollow fibers are generally packed in a bundle, and the filling rate is preferably 30 to 80 inches. In particular, when storing irregularly shaped hollow fibers or bundles of irregularly shaped hollow fibers having a plurality of fins with different heights and adjacent spacings as in the present invention, the filling rate is 4.
0~. SOS, especially at a relatively high filling rate of 50 to 80%, is extremely advantageous in that it is difficult to form close contact between hollow fibers, gaps between fins, or closed spaces between fins and hollow fibers.

You can get the benefits of That is, in the fluid separator of the present invention, since the filled hollow fiber fins are non-uniform,
It is characterized by the fact that local crowding is less likely to occur and the fluid flow state on the outside of the hollow fiber is more likely to be maintained uniformly. In addition, when the filling rate is as high as 60 to 80%, it may be difficult to store the hollow fibers, but in that case, the hollow fiber collection may be stored as a whole or divided into multiple blocks. It is preferable to store them all together by wrapping them in a spirally wound string or tape-like material, or by wrapping them in a net-like material. Threads, tapes, nets, etc. used in this process are made of water-soluble polymers or those that swell in water. It is desirable that the hollow fibers are dispersed in the same manner.

The type of the fluid separator of the present invention is not particularly limited to 15L1. For example, as typified by a hemodialyzer, a cylindrical container housing a bundle of hollow fibers, a tube plate having both ends of the hollow fibers bonded and opened. , one consisting of a blood distribution section and a collection section, and a dialysate inlet and outlet.

The fluid separator of the present invention can be used for artificial kidneys, artificial livers, plasma separation and plasma component separation, such as those described above, using hemodialysis or blood filtration.
Artificial lungs, body fluid treatment devices such as V1 water treatment, and other extreme
It can be used in filters, reverse osmosis devices, and gas separators, etc., and is particularly effective in cases such as dialyzers where good fluidity of fluid outside the hollow fiber is required.

The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples in any way.

Examples 1 and 2. Comparative Example 1.2 50 parts of polyethylene glycol (molecular weight 300) was added to 100 parts of cellulose diacetate, and the mixture was melted at 200°C and formed into a long double annular slit for finned hollow fibers. A spinneret having notches and connecting portions was used to obtain hollow fibers having a length and spacing of ff I K. Then, the cellulose was saponified and the hollow fiber bundle was assembled into a hemodialyzer having an effective area of about 1 m'. Table 1 shows the shape of the hollow fibers obtained and the characteristics of the hemodialyzer.

However, the urea dialysance was measured at 37° C. using an aqueous urea solution with an average blood side velocity of about 1.2α/Sec in the hollow fiber and water with an average flow rate of about 1.8 cyn/36C on the dialysate side. In addition, the effective membrane area in the case of a finned thread was calculated assuming that the root portion of the fin is ineffective for dialysis.

Furthermore, the tube sheet leakage rate refers to the fact that when the ends of a hollow fiber bundle are bonded together with a urethane adhesive, the adhesive does not sufficiently penetrate into the gaps between the hollow fibers, causing leakage between the dialysate side and the blood side. This refers to the rate of defective products due to the occurrence of communication points.

〔Effect of the invention〕

The irregularly shaped hollow fibers and irregularly shaped hollow fiber bundles of the present invention have the advantage that the filling state within the fluid separator filled with them tends to be uniform throughout. In other words, not only is there very little close contact between the hollow fibers in the filled state, but also it is difficult to form a sealed space between the fins or between the fins and the hollow fibers, so the fluid flow state outside the hollow fibers tends to be extremely uniform. There is. Therefore, it is extremely unlikely that the flow velocity and degree of fluid outside the hollow fiber will become locally non-uniform.
Excellent fluid separation efficiency can be obtained.

Claims (1)

[Scope of Claims] 1. In a permselective modified hollow fiber having a plurality of fins extending in the longitudinal direction on the outer periphery, the average height of each of the fins is substantially nonuniform; /Or an irregularly shaped hollow fiber characterized in that the distance between two adjacent threads is substantially different. 2. The irregularly shaped hollow fiber according to item 1, wherein the fins have 2 to 10 threads. 3. The irregularly shaped hollow fiber according to item 1 or 2, wherein the average height of the highest fin is in a range of 1.5 to 10 times the average height of the lowest fin. 4. The irregularly shaped hollow fiber according to item 1 or 2, wherein the maximum value of the distance between two adjacent threads is in a range of 1.5 to 10 times the minimum value. 5. A bundle of irregularly shaped hollow fibers in which a plurality of selectively permeable irregularly shaped hollow fibers having three or more fins extending in the longitudinal direction on the outer periphery are attached via the fins, which is necessary for attachment. An irregularly shaped hollow fiber bundle characterized in that the average height of each of the fins other than the fins is substantially different from each other and/or the distance between two adjacent fins is substantially different from each other. 6. The irregularly shaped hollow fiber bundle according to item 1, wherein the number of irregularly shaped hollow fibers is 2 to 10. 7. In a fluid separator containing permselective hollow fibers,
(1) It has a plurality of fins extending in the longitudinal direction on the outer periphery, and the average height of each fin is substantially different and/or the distance between two adjacent fins is substantially different. A permselective irregularly shaped hollow fiber and/or (2) a plurality of selectively permeable irregularly shaped hollow fibers having three or more fins extending in the longitudinal direction on the outer periphery are attached via the fins to prevent attachment. The fins are characterized in that the average height of each of the fins other than those required is substantially the same, and/or the distance between two adjacent fins is substantially the same. Fluid separator.