JPH04354521A - Hollow fiber porous separation membrane element and its manufacturing method - Google Patents

Abstract

PURPOSE:To provide the hollow fiber type porous separating membrane element made of a fluororesin which is greatly improved in heat resistance and chemical resistance and to provide the process for producing the hollow fiber type porous separating membrane element including a stage for forming the terminal sealing part of the hollow fiber type porous separating membrane element made of the fluororesin by fine molding by using a hot meltable resin, such as a hot meltable fluororesin. CONSTITUTION:This hollow fiber type porous separating membrane element is constituted by sealing the spacings between the hollow fiber type porous separating membranes and the spacings between the hollow fiber type porous separating membranes 5 and an outside cylinder by the hot meltable fluororesin 2 which is melt-molded at least at the terminal of the hollow fiber type porous separating membrane element formed by housing the bundle of the hollow fiber type porous separating membranes 5 made of the fluororesin into the outside cylinder 1. The process for producing this element in provided.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a hollow fiber porous separation membrane element, and more specifically, a fluororesin membrane element used as a gas separation membrane, dialysis membrane, reverse osmosis membrane, ultrafiltration membrane, precision filtration membrane, etc. This invention relates to a hollow fiber porous separation membrane element that uses a hollow fiber porous separation membrane and has excellent heat resistance, chemical resistance, etc.

0002

[Prior Art] Hollow fiber porous separation membranes are separation membranes that utilize the walls of hollow fibers as selective permeation membranes, including gas separation membranes, dialysis membranes, reverse osmosis membranes, ultrafiltration membranes, and precision filtration membranes. It is used as such. This hollow fiber porous separation membrane is
In order to increase the membrane area per unit volume, a hollow fiber type module is used for practical use.

[0003] A hollow fiber type module includes an element in which a bundle of hollow fiber porous separation membranes (hollow fibers) is housed in a cylindrical or other pressure-resistant outer cylinder, and has a high membrane packing density, such as water, juice, etc. , remove useful liquids such as alcohol or solvents from dust,
In addition to being able to miniaturize filtration equipment that separates bacteria from bacteria, it also has excellent pressure resistance, so it is widely used in semiconductors, food, and other fields. In particular, hollow fiber porous separation membranes made of hydrophobic resins such as fluororesins are prized for their excellent chemical resistance.

[0004] A hollow fiber type module uses an element in which a bundle of a large number of hollow fiber porous separation membranes is housed in an outer cylinder such as a cylinder, and one end of the hollow fiber porous separation membrane is sealed by heat sealing. There are closed internal pressure type separation membrane elements and internal pressure circulation type separation membrane elements with open openings at both ends. In these elements, a bundle of a large number of hollow fiber porous separation membranes is housed in an outer cylinder, and at one or both ends of the bundle there are gaps between the hollow fiber porous separation membranes and gaps between the hollow fiber porous separation membranes and the outer cylinder. is sealed with a sealant or the like.

Conventionally, as a method for sealing the gap between the outer cylinder and the hollow fiber bundle and the gap between the hollow fiber bundles, a low-viscosity resin such as epoxy resin, urethane resin, or silicone resin is applied to the end portion as a sealant. There is a known method of injecting the resin, allowing it to stand still or using centrifugal force to sufficiently fill the gap, and then heating and curing it.
issue).

However, these resins used as sealants do not have sufficient heat resistance or chemical resistance, and solutions containing acids or alkalis or organic solvents are used as solvents or cleaning liquids, or steam sterilization is required. There were limitations to its application to fields of That is, although epoxy resins have relatively excellent heat resistance, they are fragile to strong acids, strong alkalis, and some solvents, and are skin sensitizing, which limits their application to the pharmaceutical and food fields. Urethane resins have insufficient heat resistance and are not resistant to strong acids, strong alkalis, and some solvents. Silicone resin has poor solvent resistance.

On the other hand, when using a hot melt resin as a sealant for a hollow fiber porous separation membrane element, (1)
(2) A method using injection molding or extrusion molding, in which an outer cylinder containing a yarn bundle is placed in a mold, and resin is heated and melted and poured into the mold.
A method in which an outer cylinder containing a yarn bundle is placed in a mold, powdered, granular, or pelleted resin is placed in the mold, heated and melted, and air bubbles contained in the resin are defoamed. There is a method of molding a resin having through-holes, installing hollow fibers into the holes, and then heat-melting the resin.

However, in method (1), when the viscosity of the hot-melt resin is high, it is difficult to infiltrate the resin into narrow gaps such as the gap between the outer cylinder and the hollow fiber bundle or between the hollow fiber bundles. be. In method (2), it is difficult to remove air bubbles once they have entered the resin from the highly viscous resin, resulting in incomplete sealing. In method (3), it is difficult to create a large number of through holes at a high density, the inclusion of air bubbles is inevitable, and it is difficult to completely seal the gaps. Therefore, depending on these methods, it is not possible to finely mold the sealing portion using a hot-melt resin, and it is also not possible to increase the filling rate of the hollow fibers.

The greatest advantage of the hollow fiber porous separation membrane element is that it can increase the membrane area per unit volume, but for this purpose it is essential to highly fill the outer cylinder with hollow fibers. It is generally said that the filling rate of the hollow fibers (the ratio of the total volume including the lumen of the hollow fibers to the internal volume of the element) needs to be 50% or more. However, it is extremely difficult to create a hollow fiber porous separation membrane element with a high filling rate using a hot-melt resin as a sealant. In particular, hot-melt resins with excellent heat resistance and chemical resistance generally have a high melting point and high viscosity, so it has been practically impossible to use them as sealants by conventionally known molding methods.

0010

SUMMARY OF THE INVENTION An object of the present invention is to provide a hollow fiber porous separation membrane element made of fluororesin that has significantly improved heat resistance and chemical resistance. Further, an object of the present invention includes a step of forming an end sealing part of a hollow fiber-like porous separation membrane element made of fluororesin by micro-molding using a heat-melt resin such as a heat-melt fluororesin. An object of the present invention is to provide a method for manufacturing a hollow fiber porous separation membrane element.

[0011] Heat-melting fluororesin has excellent heat resistance and chemical resistance, but generally has a high melting point and high viscosity. However, it is extremely difficult to form an end seal of a separation membrane element, and a satisfactory product cannot be obtained. For example, the specific melt viscosity of a molding resin such as FEP (tetrafluoroethylene/hexafluoropropylene copolymer) is usually as high as 104 to 106 poise, and even when melted, it has almost no fluidity without pressure. Therefore, in order to use a heat-melting fluororesin as a sealant for end-sealing a hollow fiber porous separation membrane element, high pressure is required to infiltrate the resin into small gaps, and conventional molding techniques cannot It was considered virtually impossible.

However, as a result of research by the present inventors, using a molded product made by melting and molding a hot-melt resin into a predetermined shape such as a cylinder or a flat plate, and heating and melting the molded product, a hollow molded product made of fluororesin was molded. By embedding a bundle of filamentous porous separation membranes or the hollow fiber bundle and the outer cylinder in a hot-melt resin using its own weight, weight, gravity, or a combination thereof, an end-sealing portion is formed with the hot-melt resin. I found out what I can do.

[0013] In order to apply dead weight, weight, or attractive force, there are methods such as inserting a support rod such as a stainless steel rod into the hollow fiber cavity, or attaching a weight to the tip of the hollow fiber. After embedding the fiber bundle etc. in the hot melt resin, the hollow fiber porous separation membrane is mutually bonded at least at one end by cutting off the excess portion at the tip and removing the support rod. A hollow fiber porous separation membrane element is obtained in which the gap and the gap between the hollow fiber porous separation membrane and the outer cylinder are sealed with a melt-molded hot-melt resin.

According to this method, a heat-melting resin such as a heat-melting fluororesin having excellent heat resistance and chemical resistance is used as the sealant, and the sealing is complete without bubbles and has a high filling rate. A hollow fiber porous separation membrane element can be produced. wThe present invention has been completed based on these findings.

[0015]

[Means for Solving the Problems] According to the present invention, in a hollow fiber porous separation membrane element in which a bundle of hollow fiber porous separation membranes made of fluororesin is housed in an outer cylinder, at least one end portion of the hollow fiber porous separation membrane element is provided. A hollow fiber porous separation membrane characterized in that the gap between the hollow fiber porous separation membranes and the gap between the hollow fiber porous separation membrane and the outer cylinder are sealed with a heat-melting fluororesin melt-molded. elements are provided.

Further, according to the present invention, a thermofusible resin melt-molded into a predetermined shape is inserted into the inner end of the outer cylinder, and while the thermofusible resin is heated and melted, the hollow fiber-like porous fluororesin is formed. A bundle of quality separation membranes is inserted from the other end of the outer cylinder, and is embedded in the hot melt resin using its own weight, weight, gravity, or a combination of these to form an end sealing portion with the hot melt resin. A method for manufacturing a hollow fiber porous separation membrane element is provided.

Furthermore, according to the present invention, while heating and melting the hot-melt resin that has been melt-molded into a predetermined shape, an outer cylinder containing a bundle of hollow fiber porous separation membranes made of fluororesin is placed thereon. A hollow fiber porous separation membrane element characterized in that the end portion is embedded in the hot-melt resin by its own weight, weight, attraction, or a combination thereof to form an end-sealed portion with the hot-melt resin. A manufacturing method is provided.

The present invention will be explained in detail below. The hollow fiber porous separation membrane made of fluororesin used in the present invention is not particularly limited, and may be made of PTFE (polytetrafluoroethylene).
Conventionally known fibers such as hollow fibers can be used. In addition, the material of the cylindrical element outer cylinder is metal such as stainless steel, which has excellent heat resistance and chemical resistance, PTFE, FEP, etc.
Fluororesins such as PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer) are preferred.

[0019] Examples of the heat-melting resin used as a sealant in the present invention include FEP, PFA, and ETF.
E (ethylene/tetrafluoroethylene copolymer), P
CTFE (polychlorotrifluoroethylene), PVd
Examples include heat-melting fluororesins such as F (polyvinylidene fluoride). Among these, FEP and PFA are most suitable from the viewpoint of heat resistance based on resistance to steam sterilization and chemical resistance against acids, alkalis and solvents.

[0020] Furthermore, the combination of the fluororesin hollow fiber porous separation membrane and the heat-melting resin used as the sealant is better if the combination has higher affinity, and it is desirable that the resins be of the same type. For example, when PTFE hollow fibers are used, FEP or PFA is optimal as the sealant. When combining different types and properties, it is desirable to treat the surface of the hollow fiber to increase the affinity as much as possible.

The hollow fiber porous separation membrane element of the present invention and its manufacturing method will be explained below with reference to the drawings. FIG. 1 is a schematic diagram showing the end sealing portion of the hollow fiber porous separation membrane element of the present invention. Element outer cylinder 1
A large number of hollow fiber porous separation membranes 5 made of fluororesin housed in the element are separated by the heat-melting resin 2 at the ends of the elements and the gaps between the hollow fiber porous separation membranes 5 and the hollow fiber porous separation membranes 5. The gap in the outer cylinder 1 is sealed.

FIGS. 2 to 4 show an embodiment of the manufacturing method of the present invention. Even if heat-melting resin has a high melting point and high viscosity, if it is a molded product such as a cylinder or a flat plate, it can be easily melted into the desired shape using general melt processing methods such as extrusion molding and injection molding. Can be molded. Therefore, as shown in FIG. 2, a cylindrical molded product 2 of a size that can be inserted into the element outer cylinder is prepared in advance by melt-molding using a hot-melt resin, and this is placed at the end of the outer cylinder 1. Insert inside. A part of the cylindrical molded product is made to protrude from the outer cylinder 1, and is covered with a heat-resistant saucer 3 having a concave resin receiver. Next, the resin is placed so that the saucer is facing downward, and the heat-melting resin is heated and melted by the heating heater 4, so that it is spread in a cylindrical shape inside the outer cylinder.

On the other hand, a support rod 6 made of a metal such as stainless steel or a heat-resistant material such as ceramic is inserted into the inner cavity of the hollow fiber porous separation membrane 5 made of fluororesin, and the bundle of hollow fibers is inserted into the outer cylinder. When inserted from the other end of 1 and placed on the surface of the hot-melt resin that is being heated and melted, the bundle slowly sinks into the hot-melt resin due to its own weight (Figure 3). If this sedimentation is performed too quickly, there is a risk of introducing air bubbles, so it is desirable to control the sedimentation speed so that the sedimentation is performed slowly.

[0024] When the tip of the hollow fiber bundle has settled sufficiently to be at a position below the tip of the outer cylinder 1 and is embedded in the hot-melt resin, heating is stopped and the temperature is returned to room temperature. Next, the saucer 3 is removed, and as shown in FIG. 4, the excess portion 7 beyond the tip of the outer cylinder 1 is cut and removed, and the support rod 6 inserted into the hollow fiber 5 is removed. At the end, an element is obtained in which the gaps between the hollow fibers and the gap between the hollow fibers 5 and the outer cylinder 1 are sealed with the hot-melt resin 2. Figure 5 shows
FIG. 3 is a completed view of the end of the element.

[0025] In the manufacturing method of the present invention, this support rod is not necessarily necessary; for example, as shown in FIG.
The same method as described above is possible even if a weight 10 of sufficient weight is connected to the tip of the hollow fiber. If this weight is made of metal that can be pulled by magnetic force, it can also be pulled by applying a magnetic field from below. In addition, as another method, a rod made of metal or the like that is approximately equal to the inner diameter of the hollow fiber or slightly thinner is passed through the hot melt resin in advance, and this rod is inserted into the inner cavity of the hollow fiber. The hollow fibers can also be embedded in the resin by pulling from below.

FIG. 7 is a diagram showing another embodiment of the manufacturing method of the present invention. The method described above is a method in which a bundle of hollow fibers is precipitated in a hot melt resin, but the bundle of hollow fibers is inserted into the element outer cylinder in advance and the entire element outer cylinder is separated.
It is also possible to mold the end sealing portion by precipitating it in a molten resin.

As shown in FIG. 7, a hot-melt resin molded article 9 which has been melt-molded into a flat plate shape in advance is placed in a saucer 10 and heated and melted by a heating heater 4 . On the other hand, a bundle of hollow fibers 5 with a support rod 6 such as a stainless steel rod inserted into the inner cavity is placed in the outer cylinder 1, and the tip portion thereof is exposed to the outside from the outer cylinder. When the outer cylinder and the bundle of hollow fibers in such a state are placed on a hot-melt resin molded product, the tip portion sinks into the resin due to its own weight and is buried.

When the outer cylinder 1 and the hollow fiber bundle have settled sufficiently and their tips are embedded in the hot melt resin, heating is stopped and the temperature is returned to room temperature. Next, after removing the saucer 10 and cutting off the excess portion beyond the tip of the outer cylinder 1, the support rod 6 inserted into the hollow fiber 5 is removed, and the hollow fibers are connected to each other at the end. An element is obtained in which the gap and the gap between the hollow fiber 5 and the outer cylinder 1 are sealed with the hot melt resin 9.

This method is also a necessary method for producing a hollow fiber porous separation membrane element having hollow fiber openings at both ends. This is because, after sealing one end of the element and then sealing the other end, the outer cylinder and the bundle of hollow fibers have already been sealed and integrated at one end.

[0030] Furthermore, when carrying out the manufacturing method of the present invention, a heat-shrinkable tube made of the same material as the resin of the sealant is coated in advance on the end of the hollow fiber on the side to be bonded to the sealant. This increases the affinity between the hollow fibers and the resin of the sealant, making it possible to shorten the molding time and improve the filling rate of the hollow fibers.

The hollow fiber porous separation membrane element manufactured by the manufacturing method of the present invention can maintain a hollow fiber filling rate of 50 to 60%, which is the same as that of conventional products.

The manufacturing method according to the present invention is superior to conventional methods in the following points. (1) Since the melt-molded product of the hot-melt resin is simple, such as a cylinder or a flat plate, even a high-viscosity hot-melt resin can be easily molded. (2) Since the heat-melting resin as the sealant is molded in bulk in advance, the sealing is complete without air bubbles. (3) During sealing and molding, pressure is not applied to the highly viscous resin with poor fluidity, but rather to the solids such as the outer cylinder and hollow fibers, so high pressure and strong force are not necessary.

Therefore, in the production method of the present invention, a heat-melting fluororesin, which has conventionally been considered difficult to mold due to its high viscosity, is used as a sealant at the end of a hollow fiber porous separation membrane element. Therefore, heat resistance and chemical resistance can be greatly improved compared to conventionally used sealants using epoxy resins, silicone resins, urethane resins, etc. In particular, when FEP or PFA is used as a hot melt resin, strong acidity,
A hollow fiber porous separation membrane element is obtained which can be used for separation and concentration applications using strong alkaline solutions or any solvent as a solvent, and which can be repeatedly steam sterilized.

[0034]

[Examples] The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1] A PTFE (polytetrafluoroethylene) porous tube with a porosity of 65%, an average pore diameter of 0.8 μm, an inner diameter of 2 mm, and an outer diameter of 3 mm was used as a hollow fiber porous separation membrane, and the ends were sealed. 95mmφ×4 made of FEP (tetrafluoroethylene/hexafluoropropylene copolymer) as agent
A cylindrical molded product with a height of 0 mm was used.

[0036] Made of stainless steel (SUS3) with an inner diameter of 95 mmφ.
04) The above FEP molded product was inserted halfway into one end of the outer cylinder, covered with a saucer with an inner diameter of 95 mmφ and a height of 10 mm, and the saucer and the outer cylinder were connected and installed with the saucer facing down (Figure 2). .

Heat the outer cylinder and saucer for 30 minutes using a band heater.
The mixture was heated to 0° C. and left for 8 hours. When the FEP molded product is in a molten state, insert 2 mmφ stainless steel rods into the hollow fiber porous separation membrane, secure both ends with wire, bundle 586 rods, insert into the outer cylinder from above, and melt. It was slowly allowed to settle into the FEP molded product at a rate of 1 cm/hour. When it reached the bottom of the saucer, the band heater was turned off and the sample was left to stand until it returned to room temperature.

[0038] After that, remove the tray, cut and remove the FEP molded part protruding from the outer cylinder and the hollow fiber end with a stainless steel rod inserted into the hollow fiber lumen at the outer cylinder end surface, and pull out the inserted stainless steel rod. left (Figure 4).

The other end of the hollow fiber is heat-sealed and sealed, and the outer cylinder on the heat-sealed end side is further sealed with a stainless steel lid.
A closed internal pressure type hollow fiber porous separation membrane element was obtained. FIG. 1 shows a cross section of the end portion of the hollow fiber porous separation membrane element of the present invention.

In the obtained hollow fiber porous separation membrane element, no air bubbles were observed in the resin at the end sealing portion, and the adhesiveness between the resin, the hollow fibers, and the outer cylinder was also good. Further, there was no intrusion of the sealing resin into the hollow fiber lumen.

[Example 2] The hollow fiber porous separation membrane and the sealant were the same as in Example 1, and a stainless steel outer cylinder with an inner diameter of 20 mmφ and a 20 mmφ
An end sealing portion was molded in the same manner as in Example 1 using a 40 mm cylindrical FEP molded product and 21 hollow fibers. At this time, the stainless steel rod was not removed.

[0042] Next, prepare a 70 mm square FEP plate-shaped molded product with a height of 40 mm, place it in a 70 mm square metal container, rapidly melt it in a hot air constant temperature bath at 300°C, take it out, and place it in a band heater. The container and outer cylinder were heated to 300°C.While heating was continued, the outer cylinder and hollow fibers were placed on the molten FEP molded product with the one end sealed side facing up. The bundles were allowed to settle at a speed of 1 cm/h. At this time, the hollow fiber should be approximately 1 cm from the lower end of the outer cylinder.
I left it so that it stuck out. After the tip of the hollow fiber bundle reached the bottom of the metal container, the band heater was turned off and the bundle was left to cool down to room temperature (FIG. 7).

[0043] After that, the hollow fiber bundle and F
An unnecessary portion of the EP sealing part molded product was cut and removed, and the stainless steel rod was removed to obtain an internal pressure circulation type hollow fiber porous separation membrane element.

In the obtained hollow fiber porous separation membrane element, no air bubbles were observed in the resin at the end sealing portion, and the adhesiveness between the resin, the hollow fibers, and the outer cylinder was also good. Further, there was no intrusion of the sealing resin into the hollow fiber lumen.

[Example 3] As a hollow fiber porous separation membrane, PTFE with a porosity of 60%, an average pore diameter of 0.45 μm, an inner diameter of 3.5 mm, and an outer diameter of 5 mm was used.
A porous tube was used and FEP was used as the sealant. A stainless steel outer cylinder with an inner diameter of 95 mmφ similar to Example 1,
A cylindrical FEP molded product and a saucer were installed, and the FEP was melted with a band heater. At one end of the above porous tube, 185 pieces were connected to a 3.5 mmφ tube insertion portion shaped as shown in Figure 6 and a 5 mmφ brass weight with a conically cut tip, during FEP in a molten state. was allowed to settle. Further, the other end of the element is also 120 mm as in Example 2.
Using a mm square x 40 mm FEP molded product and a 120 mm square metal container with an inner part, let it settle at a speed of 0.2 cm/hour.
Unnecessary parts were cut and removed to obtain an internal pressure circulation type hollow fiber porous separation membrane element.

In the obtained hollow fiber porous separation membrane element, no air bubbles were observed in the resin at the end sealing portion, and the adhesiveness between the resin, the hollow fibers, and the outer cylinder was also good. Further, there was no intrusion of the sealing resin into the hollow fiber lumen.

[Example 4] PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer) was used as the sealant, and the sealant was heated in a hot air bath at 315° C. without using a band heater. An internal pressure circulation type hollow fiber porous separation membrane element was obtained in the same manner as in Example 2, except for melting.

In the obtained hollow fiber porous separation membrane element, no air bubbles were observed in the resin at the end sealing portion, and the adhesiveness between the resin, the hollow fibers, and the outer cylinder was also good. Further, there was no intrusion of the sealing resin into the hollow fiber lumen.

[Example 5] A PTFE outer cylinder with an inner diameter of 39 mmφ was used, 42 hollow fiber porous separation membranes similar to those in Example 3 were used, and the sealant was an FEP cylinder with a diameter of 39 mm×40 mm. A molded product was used. Further, the same operation as in Example 1 was carried out in a hot air constant temperature bath at 300° C. without using a band heater, to obtain a closed internal pressure type hollow fiber porous separation membrane element made entirely of fluororesin.

In the obtained hollow fiber porous separation membrane element, no air bubbles were observed in the resin at the end sealing portion, and the adhesiveness between the resin, the hollow fibers, and the outer cylinder was also good. Further, there was no intrusion of the sealing resin into the hollow fiber lumen.

[Comparative Example 1] The same hollow fiber porous separation membrane, element outer cylinder, saucer, and stainless steel rod as in Example 1 were used. Stainless steel rods were inserted into the inner cavity of the hollow fiber porous separation membrane, both ends of which were fixed with wire, and a bundle of 586 rods was placed into an element outer cylinder that was vertically erected on a saucer. At that time, powdered FEP (Neoflon FEP, manufactured by Daikin Corporation) was placed in the outer cylinder in advance at a height of 80 mm from the bottom. In this state, I put it in a hot air constant temperature bath at 300℃ and left it for one week.
The temperature was returned to room temperature, the saucer was removed, and the FEP portion protruding from the element outer cylinder was cut and removed. The subsequent operations were the same as in Example 1.

[0052] The obtained hollow fiber porous separation membrane element had many air bubbles in the resin at the end sealing part, and there were parts where there was no sealing resin at all between the hollow fibers or between the hollow fibers and the outer cylinder. was there.

[Comparative Example 2] The same FEP resin molded product as in Example 1 was fixed in a vise,
A honeycomb-shaped (lotus root-shaped) through hole was made with a drill (drill blade diameter, 2.8 mm). An attempt was made to drill 586 holes similar to those in Example 1, but many portions where the holes were connected occurred. After inserting 586 hollow fiber porous separation membranes in which stainless steel rods prepared in the same manner as in Example 1 were inserted and fixed into the holes, a saucer was attached and the membranes were placed in the vertically erected outer cylinder of the element. The operations after heating with the band heater were the same as in Example 1.

[0054] The obtained hollow fiber porous separation membrane element has many air bubbles in the resin at the end sealing part, and there are parts where there is no sealing resin at all between the hollow fibers or between the hollow fibers and the outer cylinder. was there.

[Comparative Example 3] 10 mm on the side of a saucer with an inner diameter of 95 mm and a depth of 20 mm.
A hollow fiber porous separation membrane, a stainless steel rod, an outer cylinder, a tray, and a band heater were prepared in the same manner as in Example 1, except that a hole with φ holes was used as the tray and the FEP molded product was not used. I set it.

[0056] While the outer cylinder and saucer were being heated to 300°C, molten FEP resin was injected into the saucer and the outer cylinder from a melt extruder connected to the saucer through a 10 mm diameter pipe. For injection, a total of 354 ml (95 mmφ x 50 mm
equivalent) in about 1 hour. After the end, another 24 hours,
After holding the temperature at 300°C and removing the saucer, the procedure was the same as in Example 1, but the FEP resin was not injected between the hollow fibers or at the end of the outer cylinder opposite to the hole in the saucer, so that satisfactory end sealing was not achieved. It was not possible to create a stop.

[Comparative Example 4] Using the same hollow fiber porous separation membrane as in Example 1, an element whose terminal end sealing portion was made of epoxy resin was prepared in the following steps. After heat-sealing both ends of 586 hollow fiber porous separation membranes and treating 3 to 5 cm of the ends with a fluororesin surface modifier (manufactured by Junkosha, Tetra Etch), the FEP of Example 5 was sealed. Instead, use epoxy resin (manufactured by Ciba Geigy: C
Y-205 100 parts by weight and HY-974J 2
3 parts by weight of the mixture) was heated to 50°C, and 354 ml was added to 1
Injected in 5 minutes.

[0058] Then, at 75°C for 3 hours, and then at 120°C.
The epoxy resin was cured by holding for 2 hours. The tray was removed and the epoxy resin portion protruding from the outer cylinder was cut to obtain a hollow fiber porous separation membrane element having the same structure as Example 5 except that the sealant was an epoxy resin. In the obtained hollow fiber porous separation membrane element, no air bubbles were observed in the resin at the end sealing part.

<Measurement of physical properties> Examples 1 to 5 Using the hollow fiber porous separation membrane elements obtained in Examples 1 to 5, an air leak test was conducted at 0.2 kg/cm2. This was not observed, and it was confirmed that the ends were completely sealed.

[0060] Furthermore, using the hollow fiber porous separation membrane elements obtained in Examples 1 to 5, the transmembrane differential pressure was 4 kg/cm.
2. Under the conditions of 400 hours, water, 40% ammonia water, 1
After conducting each filtration test using 0% hydrochloric acid, acetone, toluene, and diethylamine, an air leak test was performed again, and no air leak was observed.

Regarding the hollow fiber porous separation membrane element obtained in Example 5, concentrated sulfuric acid, 20% caustic soda,
After being immersed in 10% nitric acid for 3 months, an air leak test and a 5 kg/cm2 pressure test were conducted, but no air leak was observed.

Furthermore, using the hollow fiber porous separation membrane elements obtained in Examples 1 to 5, a temperature of 150° C. and a humidity of 10
After heating at 0% for 1 hour, rapidly cooling, holding at 4℃ for 1 hour, and heating again to 150℃ for 1 month, a heat cycle test was conducted, followed by an air leak test and 5kg/cm2.
When a pressure test was performed, no air leak was observed.

Comparative Examples 1 to 3 On the other hand, when an air leak test was conducted at 0.2 kg/cm2 using the hollow fiber porous separation membrane elements obtained in Comparative Examples 1 to 2, no air leak occurred in any of them. Admitted. In Comparative Example 3, an air leak test was not conducted because a satisfactory end sealing portion could not be produced as described above.

Comparative Example 4 Using the hollow fiber porous separation membrane element obtained in Comparative Example 4, an air leak test was conducted at 0.2 kg/cm2, and no air leak was observed. However, after conducting filtration tests for water, 40% ammonia water, 10% hydrochloric acid, acetone, toluene, and diethylamine under the conditions of a transmembrane pressure difference of 4 kg/cm2 and 400 hours, an air leak test was conducted again. %Aqueous ammonia, acetone, and diethylamine, cracks and air leaks were observed at the end sealing part. In particular, after the diethylamine filtration test, numerous cracks and partial defects were observed in the end-blocking portion.

[0065] Also, concentrated sulfuric acid, 20% caustic soda, 10%
After soaking in % nitric acid for 3 months, air leak test and 5k
When a g/cm2 pressure test was conducted, cracks and air leaks were similarly observed at the end sealing portion. Furthermore, in a heat cycle test, the end seal broke within one day.

[0066]

Effects of the Invention The hollow fiber porous separation membrane element of the present invention has improved heat resistance and chemical resistance, and the end portions are completely sealed. It is suitable for use in separation membrane modules that require sterilization or sterilization such as steam sterilization.

Furthermore, the method for producing a hollow fiber porous separation membrane element of the present invention greatly improves the fine moldability of the end-blocking portion. Therefore, even if a high viscosity heat-melting fluororesin is used as a sealant, a hollow fiber porous separation membrane element with a high filling rate can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the end sealing portion of the hollow fiber porous separation membrane element of the present invention.

FIG. 2 is a diagram illustrating one embodiment of the manufacturing method of the present invention.

FIG. 3 is a diagram illustrating one embodiment of the manufacturing method of the present invention.

FIG. 4 is a diagram illustrating one embodiment of the manufacturing method of the present invention.

FIG. 5 is a schematic diagram of the end sealing portion of the hollow fiber porous separation membrane element of the present invention.

FIG. 6 is a diagram showing a hollow fiber porous separation membrane with a weight inserted therein.

FIG. 7 is a diagram illustrating another embodiment of the manufacturing method of the present invention.

[Explanation of symbols]

1　Element outer cylinder 2　Thermofusible resin (cylindrical molded product) 3 Resin saucer 4 Heating heater 5 Hollow fiber porous separation membrane 6 Support rod 7 Cutting removal part 8. Weight 9 Heat-melting resin (flat plate molded product) 10 Resin saucer

Claims (4)

[Claims] Claim 1: A hollow fiber porous separation membrane element in which a bundle of hollow fiber porous separation membranes made of fluororesin is housed in an outer cylinder, in which at least one end of the hollow fiber porous separation membrane element has a gap between the hollow fiber porous separation membranes. and a hollow fiber porous separation membrane element, characterized in that the gap between the hollow fiber porous separation membrane and the outer cylinder is sealed with a heat-melting fluororesin melt-molded. 2. A thermofusible resin melt-molded into a predetermined shape is inserted into the end of the outer cylinder, and while the thermofusible resin is heated and melted, a bundle of hollow fiber porous separation membranes made of fluororesin is inserted. A hollow fiber-like porous material that is inserted from the other end of the outer cylinder and embedded in a hot-melt resin by its own weight, weight, attraction, or a combination thereof to form an end-sealed part with the hot-melt resin. A method for manufacturing a separation membrane element. 3. While heating and melting the hot-melt resin that has been melt-molded into a predetermined shape, an outer cylinder containing a bundle of hollow fiber porous separation membranes made of fluororesin is placed on top of the resin, and the resin is heated and melted. A method for manufacturing a hollow fiber porous separation membrane element, which comprises embedding the end portion in the hot-melt resin by attractive force or a combination thereof to form an end-sealing portion with the hot-melt resin. 4. The end portion of the hollow fiber porous separation membrane made of fluororesin to be embedded in the heat-melt resin is covered in advance with a heat-melt resin shrink tube made of the same material as the heat-melt resin. A method for producing a hollow fiber porous separation membrane element according to claim 2 or 3.