JPS5819300B2 - Method for cutting multiple hollow fibers embedded in adhesive material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting hollow fibers, and in particular provides a method suitable for manufacturing selective permeation devices such as hemodialysis devices for artificial kidneys. .

It is well known that liquid or gaseous mixtures can be selectively separated via thin membranes.

In this case, it is also well known that selectivity and diffusion rate are a function of membrane material, membrane thickness, effective surface area, differential pressure on both sides of the membrane, and temperature.

One effective method that takes advantage of the difference in the permeation rate of substances through membranes is the use of hollow fiber membranes made of polymeric substances and having selective permeation performance.

Since this method uses hollow fibers, it is possible to obtain a device that is small but has a large effective surface area, and is therefore expected to be used in many fields in the future.

For example, in a hemodialysis device aimed at saving renal failure patients from death, a large number of hollow fibers made exclusively of cellulose membranes or acrylonitrile copolymer are tightly bundled, and the hollow fiber bundles are shaped into long cylindrical or rectangular cross-sections. I try to load it inside the case.

At both ends of the case, both ends of the hollow fiber bundle are fixed with a solidifying liquid which is made of a polymer composition such as epoxy resin, polyurethane, silicone resin, etc. and has appropriate elastic properties after solidification.

As a result, the hollow fibers are fixed substantially parallel to each other and parallel to the length direction of the case, and penetrate the solidified fixing material in the same direction.

The assembly of this device requires the introduction of new methods.

For example, assuming that polyurethane is used to secure the ends of a hollow fiber bundle to both ends of a case, the polyurethane composition will tightly and completely seal around each hollow fiber and inside the case. must be fixed.

This fixing operation is called potting, and the fixing material is called a potting material.

One method for this operation is, for example, by introducing a solidifying liquid into molds attached to both ends of the case while rotating the assembled device in a centrifuge.

This device rotates the introduced resin at high speed until it hardens sufficiently, thereby preventing the liquid resin from creeping up toward the center of the case along the hollow fiber bundle due to capillary action (wicking). You can.

After the fixing material at both ends is solidified or heat treated, the mold is removed, and each hollow fiber embedded in the fixing material and passing through it is cut in a direction perpendicular to the longitudinal direction of the hollow fiber. to open the ends of the hollow fibers at the cut surface.

Then, by passing the patient's blood through the openings to the inside (hollow portion) of the hollow fibers and passing the dialysate to the outside, various components in the blood are dialyzed through the wall membranes of the hollow fibers.

The greatest difficulty encountered in assembling the devices described above is cutting the hollow fibers.

In particular, this is due to the properties of the binding material, and when cutting is carried out in the usual manner with a conventional cutting machine, such as a Ham cutting machine, the opening formed at the end of the hollow fiber is comparable to the cutting blade. It was found that the amount of rubbing caused clogging of the hollow fibers, peeling of the adhesive surface between the fixing material and the hollow fibers, or unevenness of the cut surface.

The cause of this is that the heat generated during mechanical cutting causes the adhesive material or some of the generated chips of the adhesive material to melt or soften, which causes the hollow fibers to open during the rotation of the cutting blade. Part or all of the fibers are covered and occluded, and the shear stress caused by the contact between the cutting surface and the cutting surface may cause the bonding material to separate from the bonding surface of the hollow fibers or cause the cut surface to peel off. This is thought to be due to the formation of unevenness.

An even greater problem arises when selective permeation devices are used for hemodialysis.

Blood has an inherent tendency to coagulate when it comes into contact with foreign objects, and this coagulability is accelerated when blood flow is disturbed.

Normally, when renal failure patients undergo dialysis therapy, even if heparin is used as an anticoagulant, the cut surface may not be smooth, the hollow fibers may peel off even slightly from the adhesive material during cutting, or the hollow fibers may If the fibers are cut unevenly, or if the cut surface of the hollow fibers is deviated from the cut surface of the fixing material, blood clots will form in that area and grow one after another.

As a result, the grown blood clots may cover the openings of the hollow fibers, or some of the small pieces may break off and enter the hollow portions of the hollow fibers, preventing blood from flowing through the hollow portions, resulting in a decrease in dialysis efficiency. 3 Hollow fibers are stuck to the case (
The fixing materials (potting materials) such as polyurethane, silicone rubber, and epoxy resin, which are solidifying liquids used for potting, have unique stickiness and elasticity similar to those found in rubber, so they cannot be cut. When cutting, the cutting blade becomes tangled and a smooth cut cannot be made (G).

This phenomenon also occurs when cutting only a block of polyurethane, for example, but it also occurs when cutting only a block of polyurethane, such as in a hemodialysis machine.
This also poses a problem when cutting cellulose hollow fiber bundles embedded in polyurethane resin in a penetrating state together with polyurethane.

That is, polyurethane has adhesiveness and elasticity, but
The cellulose hollow fibers have a considerable stiffness, which causes them to behave very differently towards the cutting blade.

To explain this with reference to the drawings, as shown in FIG. 1, when the hollow fibers 2 embedded in the adhesive material 1 are cut in the right angle direction by the cutting blade 3, a part of the elastic adhesive material 1 is first cut, Next, the hollow fiber 2 is about to be cut.

However, at this time, since the rigidity of the hollow fibers 2 is greater than that of the adhesive material 1, the hollow fibers 2 are not cut in the X direction as they are, but are bent from the part where they contact the cutting blade 3, as shown in FIG. I end up.

For this reason, the hollow fibers 2 are partially peeled off from the adhesive material 1 at the cut surface, and tears 4 are formed between them.

On the other hand, on the side opposite to the above-mentioned abutting part, the hollow fiber 2 is attached to the adhesive material 1.
Since the hollow fibers 2 are pressed against each other, no cracks occur, but since the hollow fibers 2 are cut in a bent state as described above, the state of the cut surface after cutting is as shown in FIG. 3.

That is, the cracks leave holes 4, and the cut surfaces of the hollow fibers 2 are oblique, so that the cut surfaces 5 are not smooth and the end surfaces of the hollow fibers 2 protrude.

It has become clear that blood clots cannot be prevented when a hemodialysis device having such a cut surface is used.

It is an object of the present invention to provide a simple, rapid, accurate and economical method for cutting hollow fibers embedded in a binding material together with the binding material.

Another object of the present invention is to open the hollow fibers at the cut surface without damaging the cut surface or partially or completely blocking the openings of the hollow fibers formed by cutting, thereby opening the hollow fibers. An object of the present invention is to provide a method for allowing fluid to flow smoothly inside the device.

Still another object of the present invention is to prevent blood coagulation, particularly in hemodialysis devices for artificial kidneys, by cutting the hollow fibers in a direction perpendicular to the length direction to form extremely smooth cut surfaces. The purpose is to provide a method for obtaining the desired results.

The present invention completely overcomes the above-mentioned drawbacks and achieves the above-mentioned objectives.

That is, the present invention preliminarily cuts the hollow fibers embedded in the fixing material to a predetermined position together with the fixing material, and then slides at high speed fixed to the drive shaft so as to form an angle with the tangential surface. The present invention relates to a hollow fiber cutting method in which the hollow fibers are cut together with the adhesive material using a straight blade, and the hollow fibers are opened at the cut surface, and in particular, the adhesive material after hardening has a durometer D hardness of 20. A preferred embodiment of the present invention relates to a method for cutting hollow fibers embedded in a bonding material, which is a method for cutting hollow fibers embedded in a bonding material. Using a cutting machine that uses a saw blade such as a band saw or a circular saw, a cutting machine that uses a straight blade such as a ham cutting machine or a band saw cutting machine, or a rotary cutting machine that uses a grindstone blade, the cutting process shown in Fig. 4 is performed. The hollow fibers 2 are cut in advance to a predetermined position x-x', and then the hollow fibers 2 fixed to the case 10 by the fixing material 1 are fixed to the fixing table 13 of the cutting device 20 shown in FIG. As shown in Figures 6 and 7, the straight blade 3 is set at an angle θ2 with the cutting surface C so that the back blade surface A of the straight blade 3 does not contact the cutting surface C, and the cutting edge line P of the straining straight blade 3 is made. is fixed to the drive shaft 11 so that it forms an angle θ3 with the sliding direction X, and then the hollow fiber 2 is
The hollow fibers 2 are cut together with the fixing material 1 repeatedly to a suitable thickness as necessary, and the hollow fibers 2 are opened at the cut surfaces.

In the cutting by the straight blade 3 described above in the present invention, the sixth
The cutting edge angle θ1 shown in the figure needs to be 5°-60).

This is because if the angle is less than 5°, the blade thickness will be too thin and the blade edge will easily break, and if it exceeds 60°, the blade will be too thick and difficult to cut.

Further, the angle θ2 between the back blade surface A of the straight blade 3 and the cutting surface C needs to be 1° or more and less than 85°.

This is because if the angle is less than 1°, the back blade surface A of the straight blade will easily come into contact with the cutting surface, and if it is 85° or more, it will be difficult to cut in the vertical direction, making it difficult to cut in either case.

From these, the sum θ of the cutting edge angle θ1 of the straight blade 3 and the angle θ2 that the back blade surface A of the straight blade makes with the cutting surface C needs to be in the range of 6° or more and less than 90°.

This is because if the angle is 90° or more, cutting in the predetermined direction will not be possible.

Furthermore, the angle θ3 that the cutting edge line P of the straight blade 3 shown in FIG. 7 makes with the sliding direction X needs to be 10° or more and 80° or less.

If it is less than 10 degrees, the sliding portion of the straight blade becomes long and the sliding time is required, and if it exceeds 800 degrees, the contact surface of the blade edge becomes too dog-like, making it difficult to cut smoothly.

Further, the sliding speed of the straight blade needs to be 1 m/min or more in order to cut the hollow fibers sharply.

The above-described cutting is performed at the predetermined position Y-Y shown in FIG.
', but the thickness d2 of one cut is 5μ
It is preferable to raise the fixing table 13 shown in FIG. 5 and repeat the cutting about 5 to 100 times so that the cutting distance is 200 μm.

If the cutting thickness d2 is less than 5μ, it is difficult to control the cutting thickness and the number of cuts required to cut to a predetermined position increases dramatically, making it impractical; if it exceeds 200μ, the part to be cut becomes thick. This is because cutting cannot be done smoothly.

These matters are also illustrated by the examples described below.

The above-mentioned fixing material used in the present invention may be made of one or more of polyurethane, silicone rubber, epoxy resin, and the like.

These materials have some degree of elasticity and adhesiveness, and have the property of being easily deformed by stress.

Further, the above-mentioned hollow fibers used in the present invention may be made of synthetic polymers, natural polymers, semi-synthetic polymers, etc., and preferably have an outer diameter of 10 to 500 μm and a film thickness of 1 to 100 μm.
It is necessary that the substance has permselectivity.

Therefore, unlike the above-mentioned adhesive materials, hollow fibers do not have such remarkable adhesiveness and elasticity, but rather often have a certain degree of rigidity, and have the property of being difficult to deform under stress.

The synthetic polymers mentioned above include polyolefins, polyesters, polyamides, silicones, polyethers,
Specific examples include polypropylene, polyethylene terephthalate, nylon, polyacrylonitrile, polymethyl methacrylate, polybenzyl glucmate, and other polypeptides, silicone polymers, and other polymers with film-forming ability. Examples include vinyl polymers and copolymers containing these as main components.

The abovementioned polymers may be used singly or as mixtures, and stereocomplexes, such as syndiotactic polymethyl methacrylate and isotactic polymethyl methacrylate complexes, may also be used.

Examples of the above-mentioned natural polymers include cellulose and collagen, and examples of the above-mentioned semi-synthetic polymers include cellulose acetate.

The constituent materials of the hollow fibers used in the present invention vary depending on the purpose, and can be selected appropriately depending on the substance to be selectively separated from the mixture.

The feature of the present invention is that by limiting the angle θ2 that the back blade surface A of the straight blade 3 makes with the cutting surface C, the back blade surface A is
As a result, the cut surface is smooth as shown in FIG. 8.

Also, the cutting edge angle θ1 of the straight blade 3, the angle θ2 that the back blade surface A of the straight blade 3 makes with the cutting surface C, the sum θ of the angle between the angle θ1 and the angle θ2, and the sliding of the straight blade 3. By limiting the speed, it is smooth and does not damage the hollow fibers.
To obtain a good cut surface without creating a gap between a hollow fiber and a fixing material.

Furthermore, the present invention is characterized by limiting the angle θ3 between the cutting edge line P of the straight blade 3 and the sliding direction The purpose of this method is to prevent the cutting edge from breaking or breaking, and to enable repeated cutting in a short period of time while maintaining a good cutting surface.

Furthermore, in order to obtain a good cut surface with this cutting method, it is preferable that the durometer D hardness of the bonding material is in the range of 20 to 60. If it is lower than this, it will be difficult to obtain a smooth cut surface.
If it is higher than this range, the wear and tear on the blade will be large and the time required for cutting will also be shortened.

Furthermore, a feature of the present invention is that even if the rigidity of the adhesive material and the hollow fibers are different, by setting the above-mentioned conditions, the adhesive material and the hollow fibers can be cut smoothly so that they are on the same plane. The above-mentioned cracks do not occur in the boundary area or the openings of the hollow fibers are deformed.
Therefore, as shown in FIG. 8, the cut surface 5 according to the present invention is extremely smooth, and the end surfaces of the hollow fibers 2 do not protrude, and the cross section of the opening is also close to a perfect circle.

Such ideal cutting was similar even for hollow fibers with less rigidity, such as silicone hollow fibers embedded in epoxy resin.

According to the hemodialysis apparatus in which the hollow fibers are cut using the cutting method according to the present invention, no blood coagulation phenomenon occurs, and no clogging of the hollow portions of the hollow fibers due to blood coagulation occurs.

This is of great significance and eliminates the greatest drawback to improvements in artificial kidneys.

The cutting method according to the present invention can also be applied to the production of selective permeation devices other than hemodialysis devices, such as devices that transfer substances from the gas phase to the gas phase, from the liquid phase to the gas phase, etc. through the wall membrane of hollow fibers. .

Next, the present invention will be explained in more detail based on the following examples.
It will be understood that the present invention is not limited to these embodiments, and can be further modified based on the technical idea thereof.

Example 1 Cellulose hollow fibers having an outer diameter of 300μ and an inner diameter of 200μ are bundled and stored in a predetermined position in a cylindrical case for hemodialysis, and both ends of the hollow fiber bundle are separated by centrifugation. Both ends of the case were fixed with polyurethane consisting of a 1:2 mixture of Sumidur PF (manufactured by Sumitomo Bayer) and castor oil.

As shown in FIG. 4, the hollow fibers 2 were lined up in the length direction of the case 10, and penetrated through the adhesive material 1 (polyurethane) fixed to both ends of the case while being embedded therein.

The durometer D hardness of the polyurethane after 48 hours of curing was 28.10 seconds at the instant of measurement.

This fixed part is cut in advance with a scroll saw at the x-x' position shown in the partial enlarged view of the fixed part in Fig. 4, and then the cutting edge angle θ1 of the straight blade 3 is set to the 74 formula as shown in Fig. 6. Maximum thickness d1 is 5 mm, back blade surface A and cutting surface C of straight blade 3
The angle θ2 formed by the equation 221 is the angle θ1 and the angle θ
2 is 30 degrees, and as shown in the plan view of FIG. 7, the angle θ3 between the sliding direction X and the cutting edge P of the straight blade 3 is 4.
Cutting was repeated 20 times at a cutting speed of 4 m/min at 5 DEG C. and a cutting thickness of 250 .mu.m to the predetermined Y-Y' position shown in FIG.

According to this method, the hollow fibers were cut together with polyurethane extremely smoothly and at high speed, and the cut surfaces were extremely smooth.

When observed with a magnifying glass, the smoothness of the cut surface was incomparably better than that of the conventional example.

Further, the opening of the hollow fiber at the cut surface was close to a perfect circle, and no deformation was observed unlike in the case of the conventional method, and it was homogeneous.

When this aperture was examined in detail with a magnifying glass, no tiny cutting debris or blockage of the aperture, which always occur in conventional methods, was found, and no peeling or cracking at the interface between the hollow fibers and polyurethane was observed. No difference in level between the hollow fibers and the polyurethane was observed.

As a result of performing hemodialysis therapy on a patient with renal failure using an artificial kidney assembled using the cutting method according to the present example, there were no troubles caused by blood clots that have often been observed in the past.

Example 2 Approximately 8,000 cellulose hollow fibers with an outer diameter of 300μ and an inner diameter of 200μ were bundled and stored in a predetermined position in a hemodialysis case with a rectangular cross section, and both ends of this hollow fiber bundle were separated by centrifugation. Vorite 689 (N
Isocyanate manufactured by Company L) and Policin
) 936 (polyol manufactured by NL) in a ratio of 48:52 to both ends of the case.

Next, as shown in Table 1, the hardness of the polyurethane after curing was controlled by changing the curing time, and the cutting speed and the angle θ3 between the cutting edge line P of the straight blade 3 and the sliding direction were changed to obtain the first It was cut in the same manner as in the example and the state of the cut was observed.

The results are shown in Table 1.

As is clear from this result, the cutting edge angle θ1 of the straight blade 3 is 5° or more and 600 or less, the angle θ2 between the back blade surface A and the cutting surface C of the straight blade 3 is 1° or more and less than 85°, and the angle θ1
It can be seen that a good cutting condition can be obtained if the sum of the angle θ2 and the angle θ2 is 6° or more and less than 90°.

Example 4 In the same manner as in the third example, cellulose hollow fibers were fixed to both ends of a hemodialysis case with a rectangular cross section.

Next, as shown in Table 3, the cutting thickness d2 is changed and the cutting edge angle θ17 of the straight blade 3 is changed. S? Angle θ222.5 between the back blade surface A of the straight blade and the cutting surface C? The sum of the angle θ and the angle θ2 is θ30, the cutting speed is 5 m/min, and the straight blade is 3.
Cutting was repeated 20 times at an angle θ of 345° between the cutting edge line P and the sliding direction to cut the fixed portion to a predetermined position, and the state of the cutting was observed.

(In the table, *(1) and *(2) are the same as the explanations in Table 1)
As is clear from the results in Table 3, the cutting thickness d2 is 5μ
A good cutting condition can be obtained in the range of ~200μ.

Although a good cutting condition can be obtained even when the cutting thickness is 5μ or less, it is difficult to control a cutting thickness of 5μ or less, and the number of cuts required to cut to a predetermined position increases dramatically. , it is not economical and is problematic in practice.

Example 5 Acrylonitrile 971y,=Mecrylsulfonic acid 3
Approximately 2,000 semipermeable hollow fibers (inner diameter approximately 280 μm) made of a copolymer with a dialysis agent were bundled and stored in a predetermined position in a dialysis cylindrical case, and both ends of this hollow fiber bundle were It was fixed with silicone rubber made from Silastic (trade name) manufactured by Dow Corning.

This fixed portion was then cut perpendicularly to the length direction of the hollow fiber using the same device as in Example 1.

The cut surface was extremely homogeneous and smooth, and the cross section of the open hollow fibers was kept perfectly circular.

When hemodialysis was actually performed using a hemodialysis apparatus equipped with hollow fiber bundles cut in this manner, almost no blood clots occurred.

Example 6 Approximately 4,800 hollow fibers (inner diameter approximately 280 μm, outer diameter approximately 350 μm) made of polymethyl methacrylate were bundled and stored in a cylindrical case for dialysis, and both ends of the fibers were tied together using Toshiba Silicone TSERT TV3402 (Toshiba Silicone made)
It was fixed with silicone rubber.

This fixed portion was then cut perpendicularly to the length direction of the hollow fiber using the same device as in Example 1.

In this example as well, an extremely smooth cut surface was obtained, almost no distortion or deformation was observed on the opening surface of the hollow fibers, and no peeling between the hollow fibers and the silicone rubber was observed.

When hemodialysis was actually performed using a hemodialysis apparatus equipped with hollow fiber bundles cut according to this example, almost no blood clotting phenomenon was observed in the hollow fibers, and the cut surface had excellent smoothness and Homogeneity was proven.

Example 7 Approximately 20,000 hollow fibers (inner diameter approximately 460 μm, outer diameter approximately 630 μm) made of cellulose acetate were bundled and stored in a cylindrical case, and both ends were coated with epoxy resin manufactured by Cemedine Co., Ltd. by centrifugation. It stuck.

This fixed portion was cut using the same device as in Example 1 above.

This cutting was carried out smoothly, and an extremely homogeneous and smooth cut surface was obtained, the openings of the hollow fibers were clean and uniform, and there was no deformation, blockage, or peeling, and the quality was extremely good.

Example 8 Approx.
000 hollow fibers (inner diameter 0.000 mm) were bundled and housed in a case for hemodialysis, and both ends of the fibers were fixed to the case with epoxy resin.

In the three examples in which this fixed portion was cut in the same manner as in Example 1, extremely smooth cut surfaces were obtained, the openings of the hollow fibers were close to perfect circles, and no distortion or deformation was observed.

Using the dialysis device assembled according to this example, an experiment was conducted on blood oxygen-carbon dioxide exchange (heart-lung machine).
No coagulation phenomenon was observed inside the hollow fibers.

Example 9 Hollow fiber made of nylon instead of cellulose (inner diameter 3
The process was carried out in the same manner as in Example 1 above, except that a film with a diameter of about 20 μm was used.

In this case as well, a smooth cut surface was obtained, there were no irregularities between the cut surface of the hollow fiber and the cut surface of the polyurethane, the openings of the hollow fiber were perfectly circular, and a high quality cut surface was obtained.

Example 10 Example 3 except that about 1,000 hollow fibers (inner diameter of about 360 μm) made of polyepichlorohydrin were used.
It was carried out in the same way.

In this case as well, the cut surface was extremely clean and smooth, with no peeling or cracking at the boundary between the hollow fiber and the silicone rubber, and a high quality cut surface could be obtained.

Example 11 The same procedure as in Example 6 was carried out except that hollow fibers made of polysulfone (inner diameter approximately 210 μm) were used.

In this example as well, an extremely clean cut surface could be obtained.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional example, where Figure 1 is a cross-sectional perspective view of the main part when cutting the part where the hollow fibers are fixed with a binding material with a cutting blade, and Figure 2 is a cross-sectional perspective view of the main part when cutting the part where the hollow fibers are fixed with a binding material. FIG. 3 is a partial cross-sectional view of the cut surface of the hollow fiber. Figures 4 to 8 show an example of the method according to the present invention, with Figure 4 being a partial cross-sectional view showing the cut portion of the hollow fiber embedded in the binding material, and Figure 5 showing the cutting machine. An example is a side view of the same, FIG. 6 is a partial side view showing cutting by the method of the present invention, and FIG. 7 is a plan view of FIG. 6,
FIG. 8 is a cross-sectional perspective view of the main part of the cut surface of the hollow fiber. In addition, in the symbols used in the drawings, 1 is a bonding material, 2 is a hollow fiber, 3 is a straight blade, and 10 is a case.

Claims (1)

[Claims] 1 Cut the hollow fibers embedded in the adhesive and having a different rigidity from the adhesive to a predetermined position along with the adhesive (1. After that, the cutting edge is at an angle with the cutting surface and cut at high speed). A method for cutting a plurality of hollow fibers embedded in a bonding material, the method comprising cutting with a sliding straight blade and opening the hollow fibers on the cut surface.