JPH11165045A - Production of hollow fiber membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing method of hollow fiber membrane module capable of preventing the clogging of a hollow fiber membrane by the permeation of a thermosetting resin adhesive into the membrane in a process of the centrifugal adhesion of the end part of the fiber bundle composed of a high division utrafiltration hollow fiber membrane or precision filtration hollow fiber membrane having large membrane pore diameter. SOLUTION: The permeation of the thermosetting resin to the lumen of the hollow fiber membrane is suppressed by applying a method by keeping the centrifugal force decreased in a period when the resin viscosity is smaller than the initial viscosity at the time of starting the injection based on the previous measured viscosity until the viscosity of resin once decreased is returned to the original viscosity, because the viscosity of the resin is decreased by the heat generation accompanied by the curing reaction of the thermosetting resin adhesive and the adhesive is easily permeated through the pore of the membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a resin is injected by centrifugal force into the end of a yarn bundle composed of a microfiltration hollow fiber membrane or a high-fractionation ultrafiltration hollow fiber membrane and cured, and the yarn bundle is bonded. The present invention relates to a method for manufacturing a hollow fiber membrane module capable of preventing a hollow portion from being blocked by a permeation of an adhesive resin in a centrifugal bonding step for sealing.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a hollow fiber membrane module, a bundle of a plurality of hollow fiber membranes is housed in a module case supporting the yarn bundle, and a resin is injected into an end of the hollow fiber membrane. It is generally known that a plurality of hollow fiber membranes are joined by curing, and this yarn bundle is adhered to a case and sealed. As a method of injecting the resin into the end portion of the hollow fiber membrane, a stationary method in which the resin is poured by gravity and allowed to stand to collect the resin, and a centrifugal method in which the resin is injected by centrifugal force are mainly used.

[0003] The stationary method can be easily bonded and sealed without the need for a device such as a centrifuge, but when the filling rate of the hollow fiber membrane bundle is high, the resin does not sufficiently permeate between the hollow fiber membranes. Therefore, a gap is formed between the hollow fiber membranes, resulting in incomplete adhesion and sealing. On the other hand, in the centrifugal method, since the resin can be injected into the gaps of the hollow fiber membranes with a force larger than the gravity, there is no gap between the hollow fiber membranes, so that complete adhesive sealing can be performed.

As a resin for bonding and sealing the hollow fiber membrane to the module case, a thermosetting resin such as an epoxy-based adhesive or a urethane-based adhesive is used for bonding strength, durability of the sealing agent, and versatility of bonding conditions. In particular, it is frequently used.

When these adhesives are cured, heat is generated by a curing reaction, and the viscosity of the adhesive is also greatly reduced. As a result, the adhesive permeates from the outer surface to the inner surface of the hollow fiber membrane. However, the hollow portion inside the hollow fiber membrane may be closed. In particular, hollow fiber membranes are microfiltration membranes (pore size 0.1 to 1 μm) or ultra-fractionated ultrafiltration membranes (pore size 0.01 to 1 μm)
In the case of 0.1 μm), the adhesive easily permeates the hollow fiber membrane.

As a solution to such a problem, Japanese Patent Application Laid-Open No. Hei 7-308550 discloses a method in which a filling substance is preliminarily inserted into the end portion of a hollow fiber membrane before performing sealing and sealing.
No. 61-97005 discloses a method in which the ends of the hollow fiber membrane are heat-treated to close the pores of the membrane, and Japanese Unexamined Patent Publication No. 61-141903 discloses a method in which the ends of the hollow fiber membrane are covered with a resin and the surface of the membrane is coated. A method of closing the pores has been proposed.

[0007]

However, in any of these methods, some processing must be performed on the end of the hollow fiber membrane module in advance, which increases the number of manufacturing steps of the hollow fiber membrane module. This leads to higher costs.

An object of the present invention is to prevent a resin from penetrating through a hollow fiber membrane so as to block a hollow portion and to provide a space between hollow fiber membranes when a hollow fiber membrane bundle is joined to a module case by a centrifugal method. It is an object of the present invention to provide a method of manufacturing a hollow fiber membrane module which can be completely sealed and sealed by penetration of a resin and which does not require pre-treatment of the hollow fiber membrane itself.

[0009]

According to the present invention, there is provided a hollow fiber membrane in which a thermosetting resin is injected and cured by centrifugal force at the end of a yarn bundle comprising a large number of hollow fiber membranes, and the yarn bundle is adhesively sealed. In the module manufacturing method, reduce the centrifugal force when the resin viscosity decreases due to the heat generated by the curing reaction of the thermosetting resin, and then increase the centrifugal force again when the resin viscosity increases thereafter. This is a method for producing a hollow fiber membrane module.

That is, the method for producing a hollow fiber membrane module of the present invention is measured in advance when a thermosetting resin is injected into the end of the hollow fiber membrane bundle by a centrifugal method to bond and seal the hollow fiber membrane bundle. Based on the change in the resin viscosity, the centrifugal force is reduced within a period in which the resin viscosity is smaller than the initial viscosity at the start of the injection until the resin viscosity decreases and returns to the original value, thereby reducing the hollow fiber membrane lumen. This is characterized in that the resin is uniformly permeated between the hollow fiber membranes by suppressing the permeation of the resin into the hollow fiber membranes by increasing the centrifugal force when the resin viscosity increases.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an outline of a method for manufacturing a hollow fiber membrane module by a centrifugal method. As shown in FIG. 1, while the hollow fiber membrane module (1) is usually centrifuged, a thermosetting resin as an adhesive is injected from a reservoir (2) provided at the center of the centrifuge, and the hollow fiber membrane module (1) is injected. Pour into the permeation port sections (3) and (3 ') of 1) to bond and seal the end (not shown) of the hollow fiber membrane.

The thermosetting resin used as the adhesive in the present invention may be any resin that cures from a liquid state and has an adhesive property to the hollow fiber membrane and the module case, such as an epoxy-based adhesive and a urethane-based adhesive. And unsaturated polyester resins, silicone resins and the like. Particularly, an epoxy adhesive having excellent adhesive strength and chemical resistance is preferable. Many of these resins generate heat during the course of the curing reaction, and this temperature rise causes the viscosity of the resin to decrease at the beginning of the reaction. Eventually, the resin viscosity reaches a minimum value, and thereafter increases as the curing of the resin progresses. Furthermore, the resin loses its fluidity after the heat generation peak, and the curing is almost completed.

FIG. 2 shows an example of a change in heat generation temperature and a change in resin viscosity when an epoxy adhesive is used.
In this example, it can be seen that the resin viscosity decreases until about 30 minutes after the resin is injected, and sharply increases after about 40 minutes. It can be seen that the exothermic peak is after about 60 minutes.

The present invention is a method for producing a hollow fiber membrane module, characterized in that the centrifugal force is reduced when the resin viscosity decreases, wherein the resin viscosity is 1/100 of the viscosity at the start of resin injection. At the time of 5 to 9/10, preferably 1/3 to 1/2, the centrifugal force can be reduced to 1/300 to 1/3, preferably 1/100 to 1/5 of the initial centrifugal force. desirable.

The point at which the centrifugal force is reduced is the point at which the resin viscosity decreases to 1/5 to 9/10 at the start of injection. If the resin viscosity is less than 1/5, the resin permeates the membrane and the hollow fiber membrane becomes The upper limit is set to 9/10 because the viscosity is inevitably reduced until the resin injection is completed. Also, the degree of decrease in centrifugal force is 1/300 to 1/3 of the initial centrifugal force.
The reason is that if the thickness is less than 1/300, a difference of 5 cm or more is made in the thickness of the adhesive layer, and the layer becomes non-uniform.
On the other hand, when the ratio exceeds 1/3, the resin permeates the membrane and the inside of the membrane is closed.

Further, the present invention is a method for producing a hollow fiber membrane module, wherein the centrifugal force is increased at the time when the resin viscosity increases, wherein the resin viscosity is 1 to 20 at the start of the resin injection. Times, preferably at the time of 1 to 15 times, the centrifugal force is 1/2 to 5 times the initial centrifugal force, preferably 1/2 to
Desirably 1.5 times. By increasing the centrifugal force again in this way, even if the resin drips down under its own weight during rotation with low centrifugal force, it can be restored to the original centrifugal surface again, and a resin layer of uniform thickness can be formed. Thus, the pressure resistance of the module can be increased.

The point at which the centrifugal force is increased again is the point at which the resin viscosity becomes 1 to 20 times that at the start of the injection. When the resin viscosity is less than 1 time, the resin permeates the membrane and the inside of the membrane is closed. Also, at the point of exceeding 20 times, if the resin drips with low centrifugal force, the resin can not recover to the original centrifugal surface and the adhesive layer will not be uniform in thickness is there.
In addition, the reason why the degree of increase in the centrifugal force is set to 1/2 to 5 times the initial centrifugal force is that if it is less than 1/2 times, the resin permeates the membrane and the inside of the membrane is blocked, and If it exceeds 5 times, the thickness of the adhesive becomes uneven.

Further, the present invention also proposes a method of manufacturing a hollow fiber membrane module in a case where the change in the centrifugal force depends on the elapsed time from the start of centrifugation. That is, the thermosetting resin is applied to the end of the yarn bundle by centrifugal force for 5 minutes or more after the start of injection.
Reduce the centrifugal force to 1/100 to 1/5 of the initial centrifugal force in less than 1 minute and continue centrifugation for 5 to 60 minutes, then increase the centrifugal force further to 1/2 to 1.5 times the initial centrifugal force. A method for producing a hollow fiber membrane module, characterized in that:

The reason why the time for reducing the centrifugal force is set to 5 minutes or more and less than 30 minutes after the start of resin injection is that the minimum time required for resin injection is about 5 minutes. This is because the light passes through the membrane and the inside of the membrane is closed.

The reason why the time for reducing the centrifugal force is set to 5 to 60 minutes is that if it is less than 5 minutes, the viscosity of the resin is still low, the resin permeates the membrane, and the inside of the membrane is blocked. 60
If the time exceeds the limit, the resin is cured and the thickness is not uniform.

When the centrifugation time is set to 5 hours or less as a method for industrially efficiently producing a hollow fiber membrane module, the method of the present invention enables complete sealing without clogging of the hollow fiber membrane. .

The hollow fiber membrane to which the present invention can be applied is not limited to a membrane type such as a reverse osmosis membrane, an ultrafiltration membrane, and a microfiltration membrane. Application to ~ 0.1 μm ultrafiltration membranes is preferred.

The material of the hollow fiber membrane used in the present invention may be any material. Examples thereof include aromatic polyether sulfone, aromatic polysulfone, acrylonitrile copolymer, polymethyl methacrylate, polyamide, polyolefin, polyvinyl alcohol, polyimide, cellulose acetate, regenerated cellulose, and a fluorine-containing resin. Of these, aromatic sulfone resins such as aromatic polyether sulfone and aromatic polysulfone have affinity for epoxy adhesives, and are particularly preferable because the effects of the present invention can be obtained.

[0024]

EXAMPLES Hereinafter, the production method of the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto.

(Example 1) A hollow fiber membrane made of aromatic polyether sulfone having an outer diameter of 1.3 mm and an inner diameter of 0.8 mm (fraction molecular weight: 50
(Average pore diameter: 0.05 μm) was impregnated with an aqueous glycerin solution and cut to obtain 2100 hollow fiber membrane bundles. After drying this yarn bundle and sealing both ends of the hollow fiber membrane with an epoxy-based adhesive, the hollow fiber membrane bundle is placed in a polysulfone cylindrical container (inner diameter).
82 mm, length 1070 mm) and set in a centrifuge. The hollow fiber membrane module is rotated so that the centrifugal acceleration becomes 100 G (100 times the gravitational acceleration), and the permeation of the hollow fiber membrane module (1) from the reservoir (2) provided at the center of the centrifuge as shown in FIG. Epoxy adhesive (Epicoat 828 (manufactured by Yuka Shell): Hardener HY932 (manufactured by Nippon Ciba Geigy): Epomate N-002 (manufactured by Yuka Shell) through ports (3) and (3 ') = 72:11: 290 g (17 (weight ratio)). The resin viscosity at the time of resin injection was 35 poise at a temperature of 35 ° C. Ten minutes after the start of the resin injection (resin viscosity of 20 poise, 4/7 of the resin viscosity at the start of the resin injection), the centrifugal acceleration was reduced from 100 G to 2 G. Then, 60 minutes after the start of resin injection (resin viscosity
(100 poise, 2.9 times the resin viscosity at the start of resin injection), the centrifugal acceleration was increased from 2 G to 100 G, and centrifugation was continued for 180 minutes. After completion of the centrifugation, when both ends of the hollow fiber membrane of the hollow fiber membrane module were cut, no clogging was observed inside the membrane, and all the holes were open. Further, when this hollow fiber membrane module was immersed in a water tank, air was injected into the module and air leaking from the cut surface of the hollow fiber membrane was inspected, and no leak was found. Furthermore, the thickness of the injected resin was uniform over the cross section of the hollow fiber membrane module.

Example 2 10 minutes after the start of resin injection
Centrifugal bonding was performed in the same manner as in Example 1 except that the centrifugal acceleration lowered after 5 minutes was set to 5G. After the centrifugation, both ends of the hollow fiber membrane of the hollow fiber membrane module were cut.
As in the case of (1), no clogging was found inside the membrane.
In the leak test, no leak was observed, and the thickness of the injected resin was uniform.

(Embodiment 3) The centrifugal acceleration is increased from 100G to 2G.
The centrifugation was continued for 180 minutes in the same manner as in Example 1 except that the time required to increase the centrifugal acceleration again from 2 G to 100 G after the reduction was changed from 60 minutes after the start of resin injection to 50 minutes. After the centrifugation, both ends of the hollow fiber membrane of the hollow fiber membrane module were cut. As a result, no clogging was observed inside the hollow fiber membrane, and all the holes were open. Further, when this hollow fiber membrane module was immersed in a water tank, air was injected into the module and air leaking from the cut surface of the hollow fiber membrane was inspected, and no leak was found. Further, the thickness of the resin was uniform over the cross section of the hollow fiber membrane module.

(Comparative Example 1) Hollow fiber was produced in the same manner as in Example 1 except that the centrifugal acceleration of the centrifuge was maintained at 100 G from the start of resin injection to the end of curing (180 minutes after the start of injection). A membrane module was manufactured. When both ends of the hollow fiber membrane of this hollow fiber membrane module were cut, clogging was observed in about 15% of all the hollow fiber membranes.

(Comparative Example 2) 30 minutes after the start of resin injection
A hollow fiber membrane module was prepared in the same manner as in Example 1 except that the centrifugal acceleration was reduced from 100 G to 2 G after 1 minute (the resin viscosity was 17.5 poise, the resin viscosity at the start of resin injection). When both ends of the hollow fiber membrane of this hollow fiber membrane module were cut, clogging was observed in about 20% of all the hollow fiber membranes.

[0030]

According to the method of the present invention, the average pore size is 0.01 μm.
Inexpensive adhesion and sealing of ultrafiltration hollow fiber membranes and microfiltration hollow fiber membranes with a high fraction of m or more are possible, eliminating the problem of clogging of the hollow fiber membranes with adhesives, and A hollow fiber membrane module that is completely sealed and has a uniform thickness of the adhesive resin layer can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a method for manufacturing a hollow fiber membrane module by a centrifugal method.

FIG. 2 is a diagram illustrating an example of a change in heat generation temperature and a change in viscosity of an epoxy adhesive.

[Explanation of symbols]

 1: hollow fiber membrane module 2: reservoir 3, 3 ': transmission port

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Sachiko Matsuoka 1239 Shin-Aizaka, Aboshi-ku, Himeji City, Hyogo Prefecture Inside Daicel Chemical Industry Co., Ltd. (72) Inventor Yoshimasa Matsumoto 2-2-3-216 Shinhiniodai, Sakai City, Osaka Prefecture

Claims (7)

[Claims] 1. A method of manufacturing a hollow fiber membrane module for injecting and curing a thermosetting resin by centrifugal force at the end of a yarn bundle composed of a large number of hollow fiber membranes and bonding and sealing the yarn bundle.
At the time when the resin viscosity decreases due to the heat generated by the curing reaction of the thermosetting resin, the centrifugal force is reduced, and thereafter, when the resin viscosity increases, the centrifugal force is increased again. A method for manufacturing a hollow fiber membrane module. 2. The time point at which the centrifugal force is reduced is a time point at which the resin viscosity decreases to 1/5 to 9/10 at the start of resin injection,
The method for producing a hollow fiber membrane module according to claim 1, wherein the centrifugal force is reduced to 1/300 to 1/3 of the initial centrifugal force. 3. The time point at which the centrifugal force is increased again is the time point at which the resin viscosity has increased from 1 to 20 times the resin injection start time, and the centrifugal force is increased to 1/2 to 5 times the initial centrifugal force. The method for producing a hollow fiber membrane module according to claim 1 or 2, wherein: 4. A method for manufacturing a hollow fiber membrane module for injecting and curing a thermosetting resin by centrifugal force at the end of a yarn bundle composed of a large number of hollow fiber membranes and bonding and sealing the yarn bundle.
The centrifugal force is reduced to 1/10 of the initial centrifugal force in 5 to 30 minutes after the thermosetting resin is injected into the end of the yarn bundle by centrifugal force.
A method for producing a hollow fiber membrane module, wherein the centrifugal force is further increased to 1/2 to 1.5 times the initial centrifugal force after the centrifugal force is reduced to 0 to 1/5 and the centrifugation is continued for 5 to 60 minutes. 5. The method for producing a hollow fiber membrane module according to claim 1, wherein the thermosetting resin is an epoxy adhesive. 6. The method according to claim 1, wherein the hollow fiber membrane is a porous membrane having an average pore diameter of 0.01 to 0.1 μm.
Item 13. The method for producing a hollow fiber membrane module according to item 9. 7. The method for producing a hollow fiber membrane module according to claim 1, wherein the material of the hollow fiber membrane is an aromatic sulfone resin.