JPH0410374B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hollow fiber membrane module. More specifically, the adhesive sealing part is arranged in layers in the length direction of the module using a flexible adhesive and a non-flexible adhesive, and the hollow part has a structure that improves the peeling resistance of the adhesive sealing part. Relating to thread-type membrane modules.

The semipermeable membrane module, which is the heart of reverse osmosis and ultrafiltration devices, is of various types depending on the application, and one of them, the hollow fiber membrane module, is compact. It is widely used in various fields due to its advantages such as small priming volume.

This hollow fiber membrane module has a length of 300 to 1000
Several thousand to tens of thousands of hollow fibers with an outer diameter of 0.1 to 1 mmφ are bundled together, inserted into a cylindrical case, and the ends are adhesively sealed using a non-flexible epoxy adhesive. After curing, cutting is performed to open the end face and for trimming, and a cap is attached by gluing, welding, or screwing, and the cap is manufactured.

(Prior Art) Conventionally, epoxy adhesives have been used alone to adhesively seal the ends of hollow fiber membrane modules.

(Problems to be Solved by the Invention) However, since this epoxy adhesive generates a large amount of self-heating during curing, when used in large quantities, temperature distribution occurs, resulting in uneven curing. As a result, strain will accumulate within the cured adhesive.

Additionally, epoxy adhesives are non-flexible,
Since the shrinkage rate is relatively high, the amount of adhesive used is large, especially in large-diameter hollow fiber membrane modules.
Inevitably, internal distortion also increased, causing problems such as peeling between the case and the adhesive.

To solve this problem, for example, after curing a non-flexible epoxy adhesive, the parts that are likely to peel off due to mechanical or thermal shock are intentionally peeled off, and then the peeling is done. Hollow fiber membrane modules have been proposed in which the same non-flexible epoxy resin is injected into the gap and bonded.
incomplete. In addition, when sealing a hollow fiber membrane module with adhesive, a rectangular silicone rubber plate with a thickness of about 1 to 5 mm, made of a material that cannot be bonded with epoxy adhesive, is rolled up around the inner periphery of the end of the cylindrical case. After sealing by injecting adhesive, the annular body formed from the strip was extracted and a flexible adhesive such as urethane or silicone was injected into the annular gap formed to adhere it. Hollow fiber membrane modules have also been proposed.

However, this method cannot prevent peeling of the outer periphery of each hollow fiber end.

This kind of peeling occurs not only during module manufacture, but also during use, especially when the case is exposed to temperature changes such as when heat sterilization is performed or cold water is used to process and clean relatively high-temperature liquids. Peeling often occurred due to the difference in expansion-contraction rates of the adhesive and the adhesive. Peeling occurs not only between the case and the adhesive, but also at the portion where the individual hollow fibers are adhesively sealed, that is, at the outer periphery of each hollow fiber.

Such peeling of the hollow fiber type membrane module causes a fatal trouble in practical use.

This is because, in a system that uses many hollow fiber membrane modules, if even one module is in this condition, it will take time to find the problem, and even if the leaking module is replaced, the contaminated system will not be able to recover. It will take a long time to clean.

Particularly in liquid processing equipment for the purpose of sterilization, even a small leakage causes a problem because even a small amount of leaked bacteria will multiply, spreading contamination to the entire system.

In view of this situation, the present inventors have completed the present invention as a result of intensive studies.

(Structure of the Invention) That is, the present invention is based on a method in which a cylindrical case is filled with hollow fiber bundles, and the hollow fiber bundles are adhesively sealed between each other and between the ends of the hollow fiber bundles and the ends of the case. A hollow fiber type membrane module, in which the composition of the adhesive in the adhesive sealing part is directed from the longitudinal end of the module to the center of the module, and includes a flexible adhesive, a non-flexible adhesive, and a flexible adhesive. A hollow fiber membrane module characterized by having adhesives arranged in layers in this order.

The key point of the present invention is to provide flexibility to the adhesively sealed portion of the hollow fiber membrane module, particularly the corner portions of the cylindrical case and the adhesively sealed portions of the individual hollow fibers, that is, the exposed portions. It makes it difficult for the initiation of delamination between the stop and around the ends of individual hollow fibers, and as a result prevents delamination in its entirety, or even if delamination occurs in areas of non-flexible adhesive. Also, the flexible adhesive part acts as a packing to prevent leakage.

Non-flexible epoxy adhesives have very high tensile strength and strong adhesion, but are relatively weak against tearing forces such as cracking forces. Therefore, the peeling between the case and the adhesive-sealed portion begins at the contact point between the case and the exposed adhesive-sealed portion, where the adhesive force is weakened, and at the outer peripheral portion of each hollow fiber.
It gradually spreads inside.

However, flexible adhesives are extremely resistant to tearing forces, so by covering this contact area with flexible adhesives, the disadvantages of non-flexible adhesives can be overcome and the advantages can be achieved. It was something I tried to keep alive.

Next, the effects of the present invention will be explained using FIG.
FIG. 1 is a schematic vertical cross-sectional view of an end portion showing an embodiment of a hollow fiber membrane module according to the present invention.
1 is an individual hollow fiber membrane, 2-2 is a flexible adhesive placed inside the module, 3-3 is a flexible adhesive placed on the same end, and 4-4 is a flexible adhesive Agent 2-2
and 3-3 are sandwiched non-flexible adhesive, and 5-5 is a case, which is usually made of acrylic resin, polysulfone resin, vinyl chloride resin, or FRP.

In FIG. 1, flexible adhesives 2-2 and 3-3
In the case of a conventional hollow fiber membrane module, the areas where peeling may start between the adhesive and the case are the upper right corner, upper left corner, and the upper left corner of the non-flexible adhesive 4-4. This is the entire inner periphery of the case corresponding to the lower right corner and lower left corner.

However, as shown in FIG.
If the flexible adhesive 2-
2 and 3-3 act as packing to prevent leakage.

Peeling starts not only between the adhesive and the inner periphery of the case, but also between the adhesive and the outer periphery of each hollow fiber, so the peeling prevention effect or packing effect of flexible adhesives 2-2 and 3-3 is similar. Demonstrated.

The flexible adhesive used in the present invention is defined in terms of chemical properties: an adhesive having a urethane bond;
An adhesive having a siloxane bond, an epoxy adhesive having a natural rubber or synthetic rubber skeleton, an epoxy adhesive having a dimer acid skeleton, etc. are selected.

In addition, when the flexible adhesive described in the present invention is defined in terms of physical properties, it has a hardness after curing of Shore hardness of 65 or less and an elongation rate of about 20% to 200%. By the way, the elongation rate of epoxy resin adhesive, which is a non-flexible adhesive that has been commonly used, is at most 5%.
It is.

Next, when adhesives are arranged in layers in the order of flexible adhesive - non-flexible adhesive - flexible adhesive, the quantitative ratio of each adhesive will be described.

Generally, when sealing the end of a hollow fiber membrane module with adhesive, it is necessary to
Calculate and inject the amount of adhesive to make the length 100mm.

The bonding length is selected to be longer or shorter as appropriate depending on the size of the module, especially the inner diameter of the cylindrical case and the filling rate of the hollow fibers.

If this adhesive length is too short, even if the above-mentioned peeling does not occur, the module will not be able to withstand the pressure applied to the module during operation, which is 1 to 10 kg/cm ² even in extreme cases. The adhesive part will be destroyed. Furthermore, if this length is made longer than necessary, the effective overlapping area of the hollow fibers will decrease, and the efficiency of the entire module will decrease.

Within this bonding length, the bonding length of the flexible adhesive disposed on both sides of the non-flexible adhesive is preferably 1 to 10% of the bonding length of the non-flexible adhesive. Therefore, it is 2-20% on both sides.

(Effects of the Invention) The hollow fiber type membrane module according to the present invention, by sandwiching the non-flexible adhesive of the adhesive sealing part between the flexible adhesive layers, has a lower case than the conventional hollow fiber type module. The peel strength between the adhesive seal and the adhesive sealing part was significantly improved.

Next, the effects of the present invention will be explained using Examples and Comparative Examples.

Example A bundle of 6,400 polyethersulfone hollow fibers with an inner diameter of 500 μm and an outer diameter of 700 μm was inserted into a polysulfone case with an inner diameter of 82 mmφ, an outer diameter of 90 mmφ, and a length of 320 mm, and this was set in a centrifugal adhesive sealing device. Then, at a temperature of 55°C and a rotation speed of 800 rpm, the urethane adhesive was applied so that the thickness of the flexible adhesive layer after opening and trimming the ends of the hollow fibers was 1 mm at the minimum part. After injecting and curing, a non-flexible epoxy adhesive was injected to a thickness of 23 mm and allowed to harden. Thereafter, urethane adhesive, which is a flexible adhesive, was injected again to a thickness of 1 mm and cured. In the hollow fiber membrane module manufactured by the above procedure, the adhesive sealing part is arranged in layers in the order of flexible adhesive - non-flexible adhesive - flexible adhesive in the length direction of the module. , the thickness of each adhesive layer is 1 mm-23 mm-1 mm. After taking it out and cutting off the end of the case, I inspected the module for leaks, but there were no leaks.

After 80°C hot water was passed through this hollow fiber module for 30 minutes, the hot water was immediately removed and 10°C cold water was passed through it for 30 minutes, but no peeling occurred between the case and the adhesive.

Comparative example A fiber bundle consisting of 6,400 polyethersulfone hollow fibers with an inner diameter of 500 μm and an outer diameter of 700 μm was inserted into a polysulfone case with an inner diameter of 82 mmφ, an outer diameter of 90 mmφ, and a length of 320 mm, and this was set in a centrifugal sealing machine. ,
A non-flexible epoxy adhesive was injected at a temperature of 55° C. and a rotational speed of 800 rpm so that the thickness between the case and the adhesive layer was 25 mm, and the adhesive was centrifugally sealed and cured.

After taking it out and cutting off the end of the case, I inspected the module for leaks, but no leaks were found.

After 80°C hot water was passed through this hollow fiber membrane module for 30 minutes, the hot water was immediately removed and 10°C cold water was passed through it, and peeling occurred between the case and the adhesive.

There were also modules that peeled off simply by passing hot water at 80°C.

Furthermore, when the module was inspected for leakage after cutting the case end, there were some hollow fiber membrane modules that had already leaked from the case and the adhesive sealing part.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal cross-sectional view of the end adhesive sealing part showing an embodiment of the hollow fiber membrane module according to the present invention, in which 2-2 and 3-3 are non-flexible adhesives 4-4.
flexible adhesive placed on both sides of the

Claims (1)

[Claims] 1. A hollow fiber type in which a cylindrical case is filled with hollow fiber bundles, and the spaces between the hollow fiber bundles and between the ends of the hollow fiber bundles and the ends of the case are adhesively sealed. It is a membrane module, and the composition of the adhesive in the adhesive sealing part is from the longitudinal end of the module to the center of the module in the order of flexible adhesive, non-flexible adhesive, and flexible adhesive. A hollow fiber membrane module characterized by being arranged in layers. 2. The hollow fiber membrane module according to claim 1, wherein the flexible adhesive is an adhesive having a urethane bond. 3. The hollow fiber membrane module according to claim 1, wherein the flexible adhesive is an epoxy adhesive having a natural rubber or synthetic rubber skeleton. 4. The hollow fiber membrane module according to claim 1, wherein the flexible adhesive is an epoxy adhesive having a dimer acid skeleton. 5. The hollow fiber membrane module according to claim 1, wherein the flexible adhesive is an adhesive having a siloxane bond.