JPH0244226B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application] The present invention provides a hemodialyzer housing a permselective finned irregularly shaped hollow fiber. More specifically, the present invention relates to a hemodialyzer containing irregularly shaped hollow fibers with fins, characterized in that the height of the fins and the distance between the fins are not substantially the same. [Prior Art] Hemodialyzers have conventionally 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 membrane.
Flowing dialysate externally, that is, between the hollow fiber membranes, and removing waste products from the blood by dialysis through the hollow fiber membranes;
It adjusts the electrolyte concentration and creates a pressure difference between the inside and outside of the hollow fiber membrane, and removes excess water from the blood through ultraviolet filtration. Furthermore, a method (blood filtration) in which a large amount of water and waste products are removed only by ultrafiltration and the excess water removed is replenished together with necessary components such as electrolytes (blood filtration) is also 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 and the like. 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 so far include increasing the amount of hollow fibers stored in the dialyzer container (filling rate) to a certain extent, or creating dialysate flow resistance by crossing hollow fibers, making the flow more uniform. It was decided to measure the Furthermore, by crimping the hollow fibers or wrapping a cover yarn around the hollow fibers, it is possible to prevent the hollow fibers from coming into close contact with each other, and to evenly distribute the substances in the container due to the flow of dialysate. Movement efficiency has been improved. However, these solutions are still not sufficient, and further improvements are desired. [Object of the Invention] The purpose of the present invention is to solve these problems and provide a hollow fiber membrane or 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] In order to achieve the above object, the present inventors conducted intensive research and found that irregularly shaped hollow fibers having multiple fins are preferable, and in particular, the height of the fins and the circumferential distance between the fins are The present invention has been achieved by discovering that it is effective to make them different. That is, the present invention provides a hemodialyzer containing a permselective hollow fiber, which has 2 to 10 fins extending in the longitudinal direction on the outer periphery, and the average height of each of the fins is substantially different. and the average height of the tallest fin is 1.5 to 10 of the average height of the lowest fin.
permselective hollow fibers are housed in which the distance between two adjacent fibers is substantially different and the maximum value of the distance between the two adjacent fibers is 1.5 to 10 times the minimum value. The present invention provides a hemodialyzer characterized by a dialysance of 170 or more. 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 not the same. In other words, the average height of the highest fin among the multiple fins is 1.5 to 10 times the average height of the lowest fin.
It is preferable to use irregularly shaped hollow fibers with a magnification of 2 to 2 times.
5, it is difficult for the hollow fibers to come into close contact with each other in the filled state, and it is also difficult to form a sealed space between the fins or between the fins and the hollow fiber wall, making it easier for the fluid outside the hollow fibers to flow more freely. Become. Further, it is preferable that the maximum value of the distance between two adjacent fins of a plurality of fins is 1.5 to 10 times, more preferably 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 with each other, 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.
Incidentally, the term "inter-strip circumferential distance" refers to the shortest distance along the circumference of the hollow fiber outer wall between the centers of two adjacent fins. The number of fins in the hollow fiber of the present invention is preferably 2 to 10, particularly preferably 3 to 8. In the case where 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 are less likely to create a closed space. If the number of fins is 11 or more, it is not practical because the membrane performance deteriorates relatively at the base of the fins. Furthermore, it is most preferable that the hollow fibers of the present invention satisfy not only the unevenness of the fin heights but also the unevenness of the distance between two adjacent fibers, but it is relatively easy to make only the fin heights different. The effect can be obtained. Note that the outer diameter, thickness, shape, height, thickness, material, etc. of the hollow fibers of the irregularly shaped hollow fibers of the present invention are not particularly limited. Practically,
The outer diameter of the hollow fiber is 100 to 400μ, more preferably 200 to 400μ.
It is preferably 300μ, and the thickness of the portion without fins is preferably 5 to 50μ, more preferably 5 to 30μ. In addition, the height of the fins is 5 to 200 μm, and even 10 μm.
It is desirable that the thickness is in the range of ~100μ, the thickness of the base of the fin is preferably 10~50μ, and the shape of the fin is such that the thickness of the base of the fin is about the same as the thickness of the middle part of the fin, or even better. Thinner layers are preferable because the effective membrane area is less reduced. Materials for hollow fiber membranes that are the subject of the present invention include:
Any material may be used as long as it can be formed into a permselective hollow fiber membrane, and specific examples thereof include cellulose, cellulose ester, polyamide,
Examples include polyacrylonitrile, polycarbonate, polymethyl methacrylate, polyolefin, polysulfone, polyethersulfone, copolymers containing these, and mixtures with other substances. In order to produce the irregularly shaped hollow fibers of the fins according to the present invention, the spinning dope (melt or solution) of the hollow fiber membrane is extruded through the double annular slit of the spinneret into a gas or a spinning bath according to a conventional method. A preferred method is to fill the hollow part with a gas or liquid that does not substantially react with or dissolve the membrane material, thereby maintaining the hollow part while spinning. For example, a plasticizer such as polyethylene glycol is added to cellulose diacetate, 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. At that time, in order to obtain the finned hollow fiber 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 with 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 Next, the hemodialyzer of the present invention will be explained.
That is, the hemodialyzer is characterized by housing a large number of irregularly shaped hollow fibers as described above. In some cases, other hollow fibers, such as permselective hollow fibers having a normal perfect circular cross-sectional shape, may also be housed. In such a hemodialyzer, a large number of these irregularly shaped hollow fibers are generally packed in a bundle, and the filling rate is preferably 30 to 80%. In particular, when housing irregularly shaped hollow fibers having a plurality of fins with different heights and adjacent spacings as in the present invention, the filling rate is low.
Even at a relatively high filling rate of 40 to 80%, especially 50 to 80%, a very excellent advantage can be obtained in that close contact between hollow fibers and closed spaces between fins or between fins and hollow fibers are unlikely to occur. That is, in the hemodialyzer of the present invention, since the fins of the filled hollow fibers are nonuniform, local crowding is less likely to occur, and the fluid flow state on the outside of the hollow fibers is likely to be maintained uniformly. There is. In addition, the filling rate is 60 to 80
%, it may be a little difficult to store the hollow fibers, but in that case, you can collect the hollow fibers as a whole or divide them into multiple blocks and add other threads or tape-like materials in a spiral shape. It is preferable to store them all together by wrapping them in a net or wrapping them in a net-like material. Threads, tape-like materials, nets, etc. used in this process are made of water-soluble polymers or materials that swell in water, and by dissolving or swelling them in water, the entire interior of the separator is filled with hollow material during fluid separation. It is desirable to ensure that the threads are evenly distributed. Further, the type of the hemodialyzer of the present invention is not particularly limited; for example, as typified by a hemodialyzer, a cylindrical container housing a hollow fiber bundle, a tube with both ends of the hollow fibers adhesively opened, These include plates, blood distribution and collection sections, and dialysate inlets and outlets. In addition, the urea dialysance in the present invention uses a dialyzer in which the inner surface area of the hollow fiber is substantially 1 ^m2 , and a urea aqueous solution is poured into the hollow part of the hollow fiber at an average speed of 1.2 cm/sec at 37°C. This refers to the situation when water is flowed outside the hollow fiber at an average speed of 1.8 cm/sec. The fluid separator such as the hemodialyzer of the present invention is applicable to the above-mentioned hemodialysis, artificial kidney, artificial liver, plasma separation, plasma component separation, artificial lung, ascites treatment, etc., and other body fluid treatment devices. It can be used in filters, reverse osmosis devices, gas separators, etc., and is particularly effective in cases where good flow characteristics of the fluid outside the hollow fibers are required, such as in dialyzers. 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 Examples 1 and 2 100 parts of cellulose diacetate and 50 parts of polyethylene glycol (molecular weight 300) were mixed together, the mixture was melted at 200°C, and a double layer for finned hollow fibers was prepared. Spinning was carried out using a spinneret having a heavy annular slit, a notch and a connecting portion to obtain hollow fibers having the lengths and intervals shown in Table 1. Next, cellulose was formed by a saponification reaction, and the hollow fiber was assembled into a hemodialyzer having an effective area of about 1 m ² based on the inner surface of the hollow fiber. 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 flow rate of about 1.2 cm/sec on the blood side in the hollow fiber and water with an average flow rate of about 1.8 cm/sec on the dialysate side. In addition, the effective membrane area in the case of a thread with fins was calculated assuming that the root portion of the fins 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 hemodialyzer filled with irregularly shaped hollow fibers of the present invention has the advantage that the filling state tends to be uniform throughout.
In other words, not only is there very little close contact between the hollow fibers in the packed 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, the flow rate and concentration of the fluid outside the hollow fibers are extremely unlikely to become locally non-uniform, and excellent fluid separation efficiency can be obtained.

Claims (1)

[Claims] 1. A hemodialyzer containing permselective hollow fibers, which has 2 to 10 fins extending in the longitudinal direction on the outer periphery, and the average height of each fin is substantially the same and the most The average height of the tallest fins is 1.5 to 10 times the average height of the lowest fin, and furthermore, the distances between two adjacent fins are substantially different, and the maximum value of the distance between the two adjacent fins is greater than the minimum value. Contains hollow fibers with selective permselectivity that is 1.5 to 10 times larger, and the urea dialysance of ¹ m2 of the inner surface area of the hollow fibers is
170 or more.