JPS5944884B2 - Hollow fiber end sealing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sealing the end of a hollow fiber and an apparatus thereof, and more particularly to a method for sealing a hollow fiber having a structure in which an adhesive enters the hollow portion of the hollow fiber to seal it. and its sealing device.

In recent years, membrane separation technology, which uses selectively permeable membranes (hereinafter referred to as membranes), has rapidly developed as a means of separating microparticles on the order of microns or smaller, such as in hemodialysis in artificial kidneys and reverse osmosis in seawater desalination. It's coming.

For devices or modules that carry out these membrane separation technologies, it is advantageous to use hollow fiber membranes in terms of small volume and excellent mechanical performance such as pressure resistance. Modules are becoming more common.

Various structures have been proposed for the hollow fiber membrane module depending on each application, and the typical ones include one in which both ends of the hollow fiber are open and held in a sealant, and one in which one end is sealed and the other is sealed. The end is open and held in a sealant (hereinafter referred to as a one-end sealed module).

Single end sealed modules are useful for ultrafiltration or reverse osmosis.

For example, US Pat. No. 3,498,909 discloses a one-end sealed module for desalination using hollow fiber membranes.

Although this one-end sealed module is industrially useful, it is actually extremely difficult to seal each hollow fiber membrane with a small diameter one by one. In the past, sealing of hollow parts was done by immersing the membrane and using capillary action to allow the adhesive to enter the hollow part, or by drawing air from the other end of the hollow fiber membrane and reducing the pressure to allow the adhesive to enter the hollow part. was going on.

However, with such a method, it is virtually impossible to uniformly and reliably seal the ends of hundreds to thousands of hollow fibers.

The present inventors have studied this problem and have already made the invention shown in Japanese Patent Application Laid-Open No. 54-82439.

That is, in a method of adhesively sealing the ends of a large number of hollow fibers using centrifugal force, an adhesive is supplied to the lower surface side in the direction in which the centrifugal force acts, and the adhesive is further applied to the upper surface side of the adhesive. This method involves supplying a non-hardening liquid with a small amount of pressure, and applying centrifugal force to the adhesive so that it enters the hollow portion of the hollow fiber and hardens.

Although a number of single end sealed modules have been manufactured using this method, the inventors have discovered that there are additional problems with this method that need to be resolved.

In other words, depending on the properties of the hollow membrane, the non-hardening liquid supplied to the top surface of the adhesive may penetrate the membrane wall of the hollow fiber membrane and enter the hollow portion before the adhesive enters the hollow fibers, causing the adhesive to In order to prevent the adhesive from entering the hollow part, it may not be possible to seal the adhesive, and the non-curing liquid supplied to the top surface of the adhesive will not penetrate through the hollow fiber membrane wall and enter the hollow part. Even if it is, it will penetrate into the membrane wall and wet the inner surface of the membrane wall.

If the adhesive enters the hollow part of this wet membrane wall and hardens, the inside of the membrane wall is wet with non-curing liquid, so the adhesion between the adhesive that entered and the inner wall of the hollow part becomes weak, and it will not work at a later date. This can cause problems.

As a result of further investigation into this problem, the present inventors found that
The present invention was completed based on the discovery that the above problems could be completely solved by using centrifugal force and using a special method for applying the adhesive.

That is, in the method of adhesively sealing the open ends of a large number of hollow fibers using centrifugal force, the present invention supplies an adhesive near the ends of the hollow fibers to be sealed and prevents the adhesive liquid from entering the inside of the hollow fibers. Then, a non-hardening liquid with a specific gravity lower than that of the adhesive is supplied to the upper surface of the adhesive on the outside of the hollow fiber, and centrifugal force is applied to cause the adhesive on the outside of the hollow fiber to melt. This hollow fiber end sealing method is characterized by discharging at least a portion of the adhesive and curing the adhesive on the inside of the hollow fiber.

The hollow fiber used in the present invention may be of any type as long as it can be used for membrane separation, such as glass, regenerated cellulose, cellulose derivatives such as cellulose ester, PVA type, polyamide type, polyester type, polyacrylonitrile type, and silicone resin type. , polysulfone, polymethyl methacrylate, etc. can be used.

In addition, its outer diameter is about 50 to 5000μ, and the film thickness is 10 to 1
000μ can be used.

Any adhesive may be used as long as it is a liquid curing type, and a -liquid type or two-liquid reaction type can be used.

Polyurethane type, silicone resin type, epoxy resin type,
Adhesives with low curing shrinkage, such as unsaturated epoxy resins, are preferred.

The second liquid used in the present invention needs to have a lower specific gravity than the adhesive and be non-curable.

The lower specific gravity is necessary because the second liquid is present on the top side of the adhesive.

Furthermore, being non-curing means having fluidity to the extent that it can be discharged from the potting case after the adhesive has hardened, but does not mean that the fluidity does not change at all.

Of course, there is no problem even if the adhesive and the second liquid react slightly and lose fluidity only near the critical surface.

Examples of the second liquid satisfying the above conditions include glycerin, polyethylene glycol, polypropylene glycol, hexanediol, bentanediol, furandiol, propylene gellicol, ethylene glycol, diacetone alcohol, butyl cellosol, ethyl cellosol, ethyl alcohol, and methyl Alcohols such as alcohol, ethers such as methyl ether, ethyl ether, and tetrahydrofuran, Kents such as acetone, methyl ethylene Kent, methyl isobutyl ketone cyclohexanone, esters such as methyl acetate and ethyl formate, hexane, petroleum benzene, liquid paraffin, etc. Hydrocarbons such as benzene, toluene, xylene, aromatics such as benzyl alcohol, and liquids such as water can be used.

Alternatively, solutions in which various solutes are dissolved in these liquids may be used.

Particularly when the second liquid tends to penetrate into the hollow part through the hollow fiber membrane, the second liquid itself has a certain viscosity or is thickened by adding and dissolving polymers or other components. It's better.

In the present invention, the hollow fibers are housed in a predetermined housing and/or a ponting case and set in a setting pipe.

At this time, it is preferable that the hollow fibers are uniformly arranged within the potting case.

The set pipes are rotated so that a centrifugal force acts toward the hollow fiber ends of the set pipes.

The potting case referred to in the present invention is for making an adhesively fixed end portion of the hollow fiber, and may be either independent of the housing or using the end portion of the housing.

While applying centrifugal force, adhesive is first supplied from the adhesive pot to the vicinity of the hollow fiber opening end of the potting case.

The supplied adhesive fills the outer space of the hollow fiber due to centrifugal force and also enters the inside of the hollow fiber from the open end of the hollow fiber.

If centrifugal force is applied for a sufficient period of time, the liquid levels of the adhesive on the inside and outside of the hollow fiber can be made approximately equal.

Preferably, after bringing the liquid level of the adhesive to such a state, the second
The liquid is supplied from the top side of the adhesive, that is, from the side close to the rotating shaft that applies centrifugal force.

The feed rate of the second liquid is determined by the viscosity of the adhesive.

If the viscosity of the adhesive is low, it can be fed at a faster rate than if it is higher.

When the viscosity of the adhesive is high, the discharge resistance becomes strong and the liquid level of the adhesive or the second liquid tends to rise.

In order to prevent the liquid level of the adhesive or the second liquid from being too far above the liquid level of the liquid level regulating means (towards the center of centrifugal force), the supply is completed within a time period in which the adhesive does not lose its fluidity. The second liquid should be fed slowly.

In the method of the present invention, the second liquid supplied to the upper surface of the adhesive pushes down the adhesive existing on the outside of the hollow fibers by the action of centrifugal force, and moves the adhesive out of the system through the liquid level regulating means described later. It is something that is discharged.

In the inventors' previous invention, the adhesive inside the hollow fiber is positively pushed upward by the pressing force of the second liquid, but in the present invention, the second liquid is The main purpose of this device is to discharge the adhesive present on the outside of the hollow fibers from the potting case.

That is, in the present invention, the second liquid is applied only to the adhesive on the outside of the hollow fiber, with respect to the liquid level on the inside and outside of the hollow fiber formed by the supplied adhesive, and the adhesive liquid level on the inside of the hollow fiber is substantially The adhesive on the outside of the hollow fiber is discharged without causing any physical change.

Therefore, only the adhesive on the inside of the hollow fiber remains inside the hollow fiber, and if this state is maintained and the adhesive is cured, the inside of the hollow fiber, that is, the hollow part of the hollow fiber, is sealed with the adhesive. .

When performing such processing, what is important is the liquid level regulating means, which will be described later.

That is, if centrifugal force is applied to the second liquid in a system where the end face of the potting case is closed, the adhesive will inevitably further penetrate into the inside of the hollow fibers, which is the same as the method of the prior invention.

On the other hand, if the end face of the potting case is an open system that communicates with the outside, the adhesive pressed by the second liquid can be discharged to the outside without entering the hollow portion of the hollow fiber.

Here, although the penetration of the adhesive into the interior of the hollow fiber, that is, the change in the adhesive liquid level inside the hollow fiber, is not completely eliminated, it is assumed that there is no substantial change to some extent.

The liquid in the potting case cannot rise toward the central axis of rotation above the liquid level determined by the liquid level regulating means.

Therefore, if the liquid level of the adhesive is set slightly below the liquid level by the liquid level regulating means, if the second liquid is supplied above it, the adhesive inside the hollow fiber will be lowered by the liquid level by the liquid level regulating means. The adhesive rises close to the surface of the hollow fiber, and from then on, only the adhesive on the outside of the hollow fiber is discharged out of the system.

In this case, the adhesive inside the hollow fiber rises quickly, so
It is possible to prevent the second liquid from penetrating or wetting the inside of the hollow fiber through the hollow fiber membrane, and the above-mentioned incomplete adhesive sealing will not occur.

On the other hand, if the liquid level of the adhesive is too low, the rising area of the adhesive inside the hollow system becomes a dog, causing the second liquid supplied to the outside to seep into the inside of the hollow fiber. It is undesirable because there is

The adhesive to be discharged may be at least a portion thereof, more particularly at least a portion of the adhesive outside the hollow system.

That is, it is sufficient that there is a difference in the adhesive liquid level between the inside and outside of the hollow fiber, and that difference is sufficient to seal the required end of the hollow fiber.

If the entire amount of the adhesive on the outside of the hollow fibers is discharged, the hollow fibers will not adhere to each other, so as soon as the adhesive is completely cured, a free end sealed module in which each hollow fiber is free can be obtained.

Further, when the adhesive is discharged so that a portion of the adhesive remains, a module is obtained in which one end of the hollow fibers is sealed and the hollow fibers are bonded to each other.

Such a module may be used as is, or the cured adhesive portion may be cut and removed to provide a free end sealed module.

The advantage of the present invention is that even if the second liquid is supplied as described above, the adhesive liquid level inside the hollow fibers, once regulated, does not substantially change, so the amount of adhesive to be discharged can be freely adjusted. It is possible.

Next, a hollow fiber end sealing device according to the present invention will be explained.

The present inventors conducted research and were able to complete a specific device for carrying out the above-described method of the present invention.

That is, the device according to the present invention seals the open end of a hollow fiber with an adhesive by applying centrifugal force, and includes a punching case that accommodates the open end of the hollow fiber, and an adhesive that is supplied into the potting case. means for supplying a second liquid onto the upper surface side of the adhesive supplied in the potting case;
The adhesive liquid level inside the hollow fibers is substantially reduced by the centrifugal force exerted on the second liquid supplied into the potting case by the liquid level regulating means. At least 1% of the adhesive on the outside of the hollow fiber without changing to
This is a hollow fiber open end sealing device characterized in that it is configured to discharge the hollow fiber opening end.

The device of the present invention includes means for supplying a second liquid to the upper surface side of the adhesive supplied in the potting case, that is, the center side of the centrifugal force, and a liquid level regulating means for regulating the liquid level in the potting case. It is characterized by having the following.

The hollow fiber end sealing device and the means for further supplying a second liquid to the upper surface side of the adhesive in the potting case are disclosed in Japanese Patent Application Laid-Open No. 54-84239, which is an earlier invention of the present inventors.
It is unknown to anyone else.

Furthermore, the device of the present invention is provided with liquid level regulating means.

The liquid level regulating means connects the end face of the potting case, that is, the end farthest from the center of centrifugal force, to the outside to form a partially open system.

A device in which the potting case is a completely closed system is disclosed in JP-A-54-84239.

Also, the device that is a completely open system is 1. It cannot be used because liquids such as adhesives do not stay inside the ponting case.

On the other hand, the liquid level regulating means in the device of the present invention retains the necessary amount of liquid in the potting case, and at the same time,
This is a means for continuously discharging the liquid in the potting case to the outside of the yarn by centrifugal force so that excess liquid does not accumulate, and in this sense it can be said to form a partially open system.

By introducing such a function into the centrifugal bonding machine, the above-mentioned object of the present invention can be easily and completely achieved.

The liquid level regulating means includes a liquid discharge port provided at or near the end face of the potting case at a portion in contact with the adhesive liquid, and a liquid discharge port connected to the liquid discharge port to direct the liquid to the upper surface side, that is, the center side of the centrifugal force. It consists of a grinding liquid channel.

The highest point of the liquid flow path becomes a liquid level lens within the potting case that is regulated by the liquid level regulating means.

That is, the liquid supplied into the potting case fills the end face of the potting case and at the same time flows into the liquid flow path via the liquid outlet.

The supplied liquid has the same liquid level in the potting case and in the liquid flow path.

Therefore, after rising in the liquid flow path and reaching its highest point, the liquid is discharged outside the system from the outlet connected to the liquid flow path, so that even more liquid remains inside the potting case. There's nothing to do.

When a hollow fiber is housed in a potting case, this phenomenon similarly occurs with respect to the liquid introduced inside the hollow fiber, that is, into the hollow portion.

Therefore, if the adhesive liquid is supplied into the potting case to a level that is almost close to the liquid level to be regulated, and then the second liquid is supplied to the upper surface of the adhesive, the second liquid will reach the liquid level regulating means. While the liquid level is regulated to a constant level, the adhesive existing on the outside of the hollow fiber is pressed, and the adhesive is discharged out of the system via the liquid level regulating means.

The amount of liquid to be discharged may be adjusted as necessary, and it is not necessary to discharge the entire amount of adhesive present on the outside.

Even if the adhesive on the outside of the hollow fiber is discharged, the liquid level inside the hollow fiber can be made substantially unchanged.

That is, the purpose can be achieved by first making the liquid level of the adhesive supplied close to the liquid level regulated by the liquid level regulating means.

Once the liquid levels of the adhesive and the second liquid are set to a predetermined level, centrifugal force continues to be applied until the adhesive almost loses its fluidity.

After that, the rotation is stopped, and if necessary, the second liquid is discharged from the potting case or the liquid level regulating means, the adhesive and solidified hollow fiber end is taken out, the adhesive part is cut by a known method, and one end of the sealed module is removed. obtain.

Preferred embodiments of the liquid level regulating means used in the present invention include the following.

That is, the liquid level regulating means includes a liquid discharge port provided at or near the end surface of the potting case, a tube body connected to the liquid discharge port, and a tube body installation in which the tube body is installed in a gently curved shape. and position fixing means for moving and fixing the relative position of the tube body installation means with respect to the potting case, the liquid level in the potting case is controlled by the position of the tube body installed on the tube body installation means. It is a device configured to regulate.

FIG. 1 is a schematic diagram showing an example of the above-mentioned liquid level regulating means.

A liquid discharge port 6 provided on the end face 5 of the potting case 4 is connected to a tube body 7, and the tube body is placed on a tube body installation means 8 for installing the tube body in a gently curved shape. Instead, it is guided to the liquid reservoir 9.

Further, the tube body installation means includes fixing means 10 for moving and fixing the relative position of the tube body installation means and the potting case.
Fixed by

In this device, the tube serves as a liquid flow path, and the uppermost point of the flow path becomes the upper end point 11 of the tube installation means.

The tube installation means may be of any shape, such as a cylindrical shape, a disc shape, or an oval shape, as long as it can be installed so that the tube body is not bent sharply and impairs the flow of the liquid.

It is also desirable to provide a groove on its surface so that the tube body can fit into it and not easily fall out.

If the tube falls off from the installation means while applying centrifugal force, not only will it be impossible to regulate the liquid level, but the potting case will become a completely open system, and all the liquid in the potting case will be drained out. Therefore, you must avoid it enough.

By moving and fixing the relative position of the tube body installation means with respect to the potting case, the regulated liquid level can be set arbitrarily.

Therefore, when producing modules of the same standard in a certain device, it is also possible to omit the mechanism that allows the position fixing means to move.

As the structure of the position fixing means, those well known to those skilled in the art can be used.

A stopper or pinch cock or the like may be attached to the tube body to adjust the flow rate of the drained liquid.

Further, it is preferable that the liquid to be discharged is led to a liquid reservoir that rotates together and recovered, but if possible, it may be discharged to the outside of the system.

The present inventors provide yet another embodiment of the liquid level regulating means.

That is, the liquid level regulating means includes a liquid inlet provided on the inner surface on the end face side of the potting case, a liquid outlet provided on the outer surface on the rotation center side of the potting case, and the liquid inlet and liquid outlet. This device consists of a liquid flow path provided in the wall of the potting case that connects the potting case, and is configured to regulate the liquid level in the potting case depending on the position of the liquid outlet.

FIG. 3 is a schematic diagram showing an example of the above-mentioned liquid level regulating means.

Since this device does not use the tube body as the liquid flow path described above, there is no need for tube body installation means or position fixing means.

This device constitutes a liquid level regulating means by effectively using the wall of the potting case.

A liquid inlet 104 provided on the inner surface 103 on the end side of the potting case, and a liquid outlet 105 provided on the outer surface of the potting case on the upper side and on the center side of the centrifugal force.
are connected by a liquid flow path 106.

The liquid in the potting case is discharged to the outside of the system through this liquid flow path.

The level of the liquid surface to be regulated is determined by the position of the liquid outlet.

Therefore, when producing a large number of modules of the same standard, the liquid level regulating means shown in this embodiment is advantageous.

It is usually preferable to connect a tube body 107 to the liquid discharge port to guide the discharge of the liquid to the liquid reservoir 108.

The liquid level regulating device can be made by making the potting case into a mating type having two or more parts and forming a groove at the joint, or by providing a gap at the joint. You can also do it.

The present invention will be explained below with reference to Examples.

Example 1 800 polyacrylonitrile hollow fiber bundles with one end trimmed and an open end were set in the setting pipe 2, and the first
It was attached to a centrifugal adhesive device as shown in the figure.

In FIG. 1, the hollow fiber bundle 1 was placed in the setting pipe 2 and set so that the open end 23 of the hollow fiber was 5 mm above the bottom 5 of the potting case 4.

When setting, a comb-shaped tool was inserted into the hollow fiber bundle slightly closer to the center of rotation than the second liquid supply port 13 in order to make the area near the open end of the hollow fiber bundle sparse.

At the bottom of the potting case 4, there is an adhesive supply pipe 12 that supplies adhesive from the adhesive pot 3 to the potting case, and a second liquid inlet 15 provided at the center of rotation of the centrifugal adhesive machine. The second liquid supply port 13 opens on the upper surface side of the adhesive of the case 4 (as viewed from the direction of centrifugal force)
An adhesive discharge tube body 7 which opens into a liquid reservoir 9 through a liquid level regulating means 8 was attached to the bottom of the potting case and the second liquid supply pipe 14 connecting the two.

These tubes used were vinyl tubes with an inner diameter of 6 or more.

Next, 300g of urethane adhesive with a specific gravity of 1.04 is poured into the adhesive pot 3, and a centrifugal force of 40G is applied to supply the adhesive from the adhesive pot 3 to the potting case 4, I filled the inside with adhesive.

As a 1-minute wave second liquid, 150 g of liquid paraffin having a specific gravity of 0.85 was flowed into the second liquid inlet 15 at a rate of 20 g/min.

After continuing to apply centrifugal force for 3 hours until the adhesive hardens at 30°C, the centrifugal force was removed and the second liquid was discharged from the discharge port 24. When the hollow fiber bundle was taken out, one end was thick. A 15 mm adhesive-solidified hollow fiber bundle was obtained.

Next, 30 mm from the adhesive end (257177 mm from the hollow fiber end)
When one section was cut, each hollow fiber was completely separated, and the adhesive had penetrated into the hollow fiber up to 15 mm from the end, sealing it. No leakage occurred.

At the same time, each hollow fiber was made open at the other end by a known method and held by a sealing material.

Examples 2 to 6 In the same manner as in Example 1 (Example 6 used the apparatus shown in Figure 3), hollow fibers, adhesive, second liquid, centrifugal force, and the second liquid started flowing in from the start of operation. The tests were carried out under the conditions shown in Table 1 regarding the time required to complete the test, the inflow rate of the second liquid, the operating time of the centrifuge, and other conditions.

The results are shown in Table 1.

The results of Example 1 are also shown in Table 1.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway view showing an example of the device according to the present invention, and FIG. 2 is a partially enlarged view of the device shown in FIG. FIG. 3 is a partially cutaway view showing another example of the device according to the invention.

Claims (1)

[Claims] 1. In a method of adhesively sealing the open ends of a large number of hollow fibers using centrifugal force, an adhesive is supplied near the ends of the hollow fibers to be sealed, and the adhesive is applied to the inside of the hollow fibers. A centrifugal force is applied so that the liquid enters, and then a non-curing liquid with a specific gravity lower than that of the adhesive is supplied to the upper surface of the adhesive on the outside of the hollow fiber, and a centrifugal force is applied to cause the liquid to enter the adhesive. at least one of the adhesives
1. A method for sealing an end of a hollow fiber, the method comprising: discharging the end of the hollow fiber, and curing an adhesive on the inside of the hollow fiber. 2. A device for sealing an open end of a hollow fiber with an adhesive by applying a centrifugal force, which comprises a potting case for accommodating the open end of a hollow fiber, means for supplying an adhesive into the potting case, and comprising means for supplying a second liquid to the upper surface side of the adhesive supplied in the potting case, and liquid level regulating means for regulating the liquid level of the second liquid supplied in the potting case, The centrifugal force applied to the second liquid supplied into the potting case by the liquid level regulating means causes at least one portion of the adhesive on the outside of the hollow fiber to be removed without actually changing the liquid level of the adhesive on the inside of the hollow fiber. 1. A hollow fiber opening end sealing device, characterized in that the hollow fiber opening end sealing device is configured to discharge a portion of the hollow fiber. 3. In the invention set forth in claim 2, the liquid level regulating means comprises a liquid discharge port provided at or near the end face of the potting case, and a tube body connected to the liquid discharge port; The tube body installation means includes a tube body installation means for installing the tube body in a gently curved shape, and a position fixing means for moving and fixing the relative position of the tube body installation means with respect to the potting case, and the tube body installation means is installed on the tube body installation means. A hollow fiber opening end sealing device configured to regulate the liquid level in a potting case by the position of a tube body. 4 In the invention stated in claim 2,
The liquid level regulating means connects a liquid inlet provided on the inner surface on the end face side of the potting case, a liquid outlet provided on the outer surface on the rotation center side of the potting case, and the liquid inlet and the liquid outlet. A hollow fiber opening end sealing device comprising a liquid flow path provided within a wall of a potting case and configured to regulate the liquid level within the potting case depending on the position of the liquid outlet.