JPH0947643A - Process and device for manufacturing dual hollow fiber membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process and a device thereof for easily and stably manufacturing a polymer thin membrane of superior penetration performance and separation performance on the outer surface of a microporous hollow fiber supporting membrane. SOLUTION: In a process of manufacturing a dual hollow fiber membrane provided with a separation active layer composed of a polymer thin membrane on the surface of a microporous hollow fiber supporting membrane, when the porous hollow fiber supporting membrane 1 is brought into contact with a first solution and then with a second solution, the porous hollow fiber supporting membrane is brought into contact with the first and second solutions in a container 2 opened in the slit shape and formed parallel with the moving direction of the porous supporting membrane while being moved in the up and down direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a semipermeable separation membrane used for selectively permeating a solid or a solute from a liquid mixture, and an apparatus for producing the same. More specifically, the present invention relates to a method and an apparatus for producing a composite hollow fiber membrane by forming a high molecular polymer thin film having selective permeability on the surface of a microporous hollow fiber support membrane by a so-called interfacial polymerization method. The composite hollow fiber membrane obtained in this way enables desalination of seawater, desalination of tap water, recovery of valuable substances in aqueous solution, wastewater treatment, removal of impurities in water, and the like.

[0002]

2. Description of the Related Art Separation and concentration of a liquid mixture by a membrane method are performed by:
Compared to separation technology such as distillation, it is an energy-saving method and it does not change the state of the substance, so it concentrates fruit juice, food fields such as separation of beer enzymes, drinking water by desalination of seawater and brackish water, production of industrial water, etc. It is widely used in various fields such as water purification field such as ultrapure water production in electronic industry, aseptic water production in pharmaceutical industry and medical field, and recovery of valuable materials from industrial wastewater. The expansion of such applications has promoted the development of new separation membranes and new separation techniques using separation membranes, and in particular, has seen rapid development in recent years. What has spurred this development is the need in the ultrapure water field, where the demand for higher-quality semiconductors has increased with the high integration of semiconductors. It may be the establishment of a composite film forming technology by the interfacial polymerization method that has made progress.

Generally, an active layer and a support layer made of the same material are called an asymmetric membrane, and a material made of different materials is called a composite membrane. The asymmetric membrane can be obtained by the phase inversion method, while the composite membrane is formed by the same operation as the asymmetric membrane to form a supporting film, and then the coating method, the interfacial polymerization method, the plasma polymerization method, etc. on the surface of the film. Can be obtained by forming a thinner active layer.
Among these, the interfacial polymerization method is a method in which two kinds of reactive monomers are dissolved in water and an organic solvent immiscible with water, respectively, and the solutions are brought into contact with each other and reacted at the interface to generate a polymer. This is a method for obtaining a composite membrane by performing it on the surface of a microporous support membrane made of polysulfone. The present invention relates to a method and an apparatus for producing a composite hollow fiber membrane obtained by this interfacial polymerization method.

A first solution containing one reactive compound A capable of reacting with each other to form a polymer and a second solution containing the other reactive compound B and immiscible with the first solution are successively finely divided. A reverse osmosis membrane is a research on composite membrane formation technology by a so-called interfacial polymerization method in which a porous support membrane is brought into contact and the reactive compounds are interfacially polymerized with each other on the surface of the microporous support membrane to form a thin film. North Star Rese mainly in the field of
At the arch and Development Institute, concrete results were NS-100 (1972), NS-200 (1973), NS-300.
(1977) and FT-30 (1978) etc.

Among these, NS-100 is a polysulfone ultrafiltration membrane coated with an aqueous solution of a water-soluble amine polyethyleneimine, and then contacted with a hexane solution of a tolylene diisocyanate, a difunctional monomer that reacts with an amino group. To form a water-insoluble polymer having a urea bond (JP-A-49-133282). In addition, NS-200 uses furfuryl alcohol instead of the polyethyleneimine, and an aqueous solution containing this and sulfuric acid or the like as an acid catalyst is applied to the surface of the polysulfone microporous support membrane, and heat treated at about 150 C to crosslink the polymer. And sulfonation are carried out simultaneously to form an active layer composed of a water-insoluble polymer (JECadotte et.al., OSW PB-Rep., No.982 (19
74)). Furthermore, NS-300 uses piperazine instead of the polyethyleneimine, and an aqueous solution containing this and a basic compound as an acid scavenger is applied to the surface of the polysulfone microporous support membrane to prepare a bifunctional and trifunctional carboxylic acid chloride. A water-insoluble polymer having an amide bond was formed by contacting with a hexane solution containing (JP-B1-38522, USP-4,259,183, JECadotte et. Al., OSW PB-Re).
p., 80-127574), FT-30 is a polymer in which a water-insoluble polymer having an amide bond is formed in the same manner as NS-300 by using metaphenylenediamine in place of the piperazine (USP-4,277,344, JP-A-2000). 55-147106).

The method for producing the composite membranes shown in these documents is such that the microporous support membranes are immersed in a bath of a first solution containing one reactive compound A capable of reacting with each other to form a polymer. After removing the excess first solution, it is subsequently immersed in a bath of a second solution which is immiscible with the first solution and which contains the other reactive compound B to give the surface of the microporous support membrane. In the above method, the reactive compounds are interfacially polymerized with each other to remove the solvent of the second solution to form a thin film.

Further, as a method for producing a composite hollow fiber membrane in which a polymer thin film is formed by an interfacial polymerization reaction on the surface of a microporous support membrane having the shape of a hollow fiber, a guide roll is provided in a reaction solution tank, A method of continuously immersing a microporous hollow fiber support membrane in a solution through this roll is disclosed in JP-A-60-172.
It is disclosed in Japanese Patent No. 311, Japanese Patent Laid-Open No. 63-205108, and Japanese Patent Laid-Open No. 2-6848. Furthermore, PB Report 81-16721
5 shows a manufacturing method in which a microporous hollow fiber support membrane is continuously immersed in and passed through a piperazine aqueous solution bath and a cyclohexane solution tank of acid chloride, and JP-A No. 2-2842 discloses.
Disclosed is a method for producing a composite hollow fiber membrane in which a thin film of crosslinked polyamide is formed on the outer surface by impregnating a microporous hollow fiber supporting membrane with a polyfunctional amine solution, air-drying, and then immersing it in a polyfunctional acid chloride solution. Has been done.

On the other hand, in US Pat. No. 4,980,061, JP-A-62-95105, and JP-A-60-87807, the first solution and the second solution are brought into direct contact with each other to make them immiscible. Disclosed is a method for producing a composite hollow fiber membrane in which a microporous hollow fiber support membrane is passed through an interface formed from an acidic solution to form a polymer thin film on the outer surface. Further, in JP-A-6-114246, a tank for immersing the microporous hollow fiber supporting membrane in the second solution is provided with a weir or a hole on at least one of the surfaces where the microporous hollow fiber supporting membrane enters and leaves the tank. There is disclosed a manufacturing method in which the second solution is overflowed from this weir or jetted from a hole using a tank provided with the above, and the microporous hollow fiber support membrane is immersed in the second solution.

[0009]

However, when continuously forming a high molecular polymer thin film on a microporous support film by an interfacial polymerization reaction, a conventional method of dipping through a guide roll (Japanese Patent Laid-Open No. 60-172311). Publication, JP-A-63
-205108 and Japanese Patent Laid-Open No. 2-6848) is applied to a hollow fiber membrane as it is, an interfacial polymerized thin film is formed on the outer surface of the microporous hollow fiber supporting membrane, and the microporosity of a guide roll or the like is formed. There is a problem that the hollow fiber supporting membrane cannot be applied to the outer surface of the continuous microporous hollow fiber supporting membrane because it is inevitable to contact the transporting means and the formed thin film is peeled or damaged. Therefore, at least when manufacturing a composite hollow fiber membrane, it is necessary to immerse the microporous hollow fiber support membrane in a contactless manner with a hollow fiber transfer means such as a guide roll in a solution tank for interfacial polymerization reaction. It was

Further, in the conventional method for producing a composite hollow fiber membrane by the interfacial polymerization method, the first solution and the second solution are brought into direct contact with each other, and the microporous hollow fiber supporting membrane is passed through the formed interface. In the method of forming a polymer thin film on the outer surface of a microporous hollow fiber support membrane (US Pat. No. 4,980,061, JP 62-95105, JP 60-87807) The thin film formed on the outer surface of the porous hollow fiber supporting membrane is dried and transferred to the heat treatment step without contacting the transfer means of the microporous hollow fiber supporting membrane such as a guide roller during formation to support the fine porous hollow fiber supporting film. It is possible to immobilize a thin film on the surface of the film. However, since the polymerized membrane formed in a plane at the liquid-liquid interface is laminated on the curved microporous hollow fiber support membrane, a uniform thin film cannot be formed on the outer surface of the microporous hollow fiber support membrane. Since the high molecular polymer thin film formed in (1) is simply laminated on the microporous hollow fiber support membrane, the problem that the adhesion between the microporous hollow fiber support membrane and the thin film is low and the above-mentioned liquid-
Among the thin films formed at the liquid-liquid interface, those that are not associated with the microporous hollow fiber support membrane increase in thickness over time,
This may hinder the formation of a thin film on the outer surface of the microporous hollow fiber support membrane, and there is a problem that it is difficult to form a uniform thin film on the outer surface of the microporous hollow fiber support membrane. It is difficult to obtain high performance and separation performance,
Poor performance stability. In addition, after soaking in the first solution,
It is impossible to introduce a step of removing or drying the excess amine solution adhering to the microporous hollow fiber support membrane,
There is a potential problem that the degree of freedom in manufacturing method conditions is poor.

Further, in the conventional method for producing a composite hollow fiber membrane by the interfacial polymerization method, when the microporous hollow fiber support membrane is immersed in the second solution, the microporous hollow fiber support membrane is added to the second solution. As a tank for dipping, a tank having a weir or a hole provided on at least one of the surfaces through which the microporous hollow fiber support membrane enters and leaves the tank is used, and the second solution overflows from this weir or is jetted from the hole. When the method of immersing the microporous hollow fiber support membrane in the second solution (Japanese Patent Laid-Open No. 6-114246) is applied, at least while the microporous hollow fiber support membrane is immersed in the second solution. In order to move the microporous hollow fiber support membrane horizontally, it is necessary to secure an installation space for the second solution tank, and in addition to this, when a drying step or a heat treatment step is required after the second solution immersion. More space for installation There is a potential problem that is required.

[0012] The present invention is intended to solve such a problem, in which the interfacial polymerization reaction is carried out in a non-contact manner with a guide roll or the like, and only the surface of the microporous hollow fiber supporting membrane is treated with the second solution. An object of the present invention is to provide a method for easily and stably producing a composite hollow fiber membrane having excellent permeation performance and separation performance by bringing it into contact with each other, and an apparatus that enables this.

[0013]

The present invention has the following constitution in order to solve such problems. That is, the present invention provides a first membrane containing at least one reactive compound A when obtaining a composite membrane in which a separation active layer made of a polymer thin film is provided on the surface of a microporous hollow fiber support membrane, A second solution containing at least one reactive compound B capable of reacting with the reactive compound A to form the high molecular weight polymer thin film, which is substantially immiscible with the first solution, is successively added to the fine solution. The porous hollow fiber support membrane is brought into contact with the surface of the microporous hollow fiber support membrane to carry out an interfacial polymerization reaction which produces a high molecular polymer by the reaction of the reactive compounds A and B to form a continuous composite membrane. In the method for producing, the microporous hollow fiber support membrane is provided with the first
At the time of contacting with a solution and subsequently contacting with the second solution, at least the second solution is supplied to a container having upper and lower openings in the shape of slits, and the microporous hollow fiber support membrane is introduced into the container, which is then There is provided a method for producing a composite hollow fiber membrane, characterized in that the microporous hollow fiber support membrane is brought into contact with the solution in the container by passing the solution in the vertical direction.

Further, in obtaining a composite membrane in which a separation active layer made of a polymer thin film is provided on the surface of a microporous hollow fiber support membrane, a first solution containing at least one reactive compound A, A second compound containing at least one reactive compound B capable of reacting with the reactive compound A to form the polymer thin film, and which is substantially immiscible with the first solution;
The microporous hollow fiber support membrane is brought into contact with a solution in order, and an interfacial polymerization reaction for producing a high molecular polymer by the reaction of the reactive compounds A and B is performed on the surface of the microporous hollow fiber support membrane,
In the method for producing a continuous composite membrane, at the time of contacting the microporous hollow fiber support membrane with the first solution and subsequently with the second solution, at least the second solution is opened in the upper and lower slits. A step of bringing the microporous hollow fiber supporting membrane into contact with the solution present in the container by feeding the microporous hollow fiber supporting membrane into the container and then passing it through in the vertical direction. An apparatus for producing a composite hollow fiber membrane is provided.

In the present invention, the microporous hollow fiber support membrane is a membrane that does not exhibit substantially any separation performance with respect to an object to be separated and supports the above-mentioned polymer thin film, and has a conventionally known microporous property. Any hollow fiber support membrane may be used, but the outer surface thereof has fine pores of preferably 0.1 μm or less, more preferably 0.05 μm or less, and the structure up to the back surface other than the outer surface is fluid permeable. In order not to increase the resistance more than necessary, it is preferable that the pores are larger than the fine pores on the outer surface, and any of mesh-like, finger-like void or a mixed structure thereof may be used. The permeation performance is shown for the case of reverse osmosis membrane as an example.The permeation amount per unit pressure and unit area is 0.01 to 0.2 m ³ / in the case of high pressure reverse osmosis membrane that can be used for seawater desalination.
(M ² · day · (kg / cm ² )), preferably 0.02 to 0.1m ³ / (m ² ·
Day ・ (kg / cm ² )), for low pressure reverse osmosis membranes used at 15 kg / cm ² or less 0.2-10 m ³ / (m ²・ day ・ (kg / cm ² )), preferably 0.5- It is 5m ³ / (m ² · day · (kg / cm ² )). If the amount of water permeation is too small, the permeation performance of the resulting composite hollow fiber membrane will be small, and if it is too large, the strength as a supporting membrane will be small and the microporous hollow fiber supporting membrane may be destroyed depending on the operating pressure. is there.

As a material for the microporous hollow fiber supporting membrane, any material can be used as long as it can be formed into the microporous hollow fiber supporting membrane. However, in producing a composite membrane by the production method according to the present invention, it is necessary that the microporous hollow fiber support membrane is not chemically damaged by the first solution or the second solution, chemical resistance, From the viewpoint of film properties, durability, etc., polysulfone, polyether sulfone, polyacrylonitrile, polyethylene, polypropylene, it is preferable to have at least one selected from polyamide as a main component, more preferably polysulfone,
It is preferable to have at least one selected from polyether sulfone as a main component.

The size of the microporous hollow fiber support membrane is not particularly limited, but considering the operability during membrane formation, the membrane area of the module, and the pressure resistance, the outer diameter is 100 μm to 2000 μm, and the inner diameter is 30 μm to 1800 μm. Is preferable, and the outer diameter is
It is more preferable that the inner diameter is 150 μm to 500 μm and the inner diameter is 50 μm to 300 μm. Furthermore, it is necessary to withstand at least a pressure higher than the operation pressure of the composite hollow fiber membrane. Such a microporous hollow fiber supporting membrane can also be selected from the above materials, and can be usually produced by a known dry-wet film forming method or melt film forming method. Furthermore, if necessary, a known wet heat treatment (PB Report 76-24866) can be applied to the microporous hollow fiber support membrane after the membrane formation.
6, JP-A-58-199007) and hot water treatment (JP-A-60-1)
90204). Further, if necessary, the first solution may be impregnated in advance so that the first solution is not excessively impregnated.

In the present invention, the separation active layer composed of a polymer thin film has substantially separation performance which can be obtained by an interfacial polymerization reaction. For example, polyfunctional amine and polyfunctional acid halide. Examples thereof include polyamides that can be obtained by the interfacial polycondensation reaction, or polyureas that can be obtained by the interfacial polymerization reaction of a polyfunctional amine and a polyfunctional isocyanate. The thickness of the polymer thin film is preferably as thin as there are no pinholes, but it is necessary to have an appropriate thickness in order to maintain mechanical strength or chemical resistance. Considering film forming stability, permeation performance, etc., the thickness is preferably 1.0 μm or less, more preferably 0.5 μm or less. A protective layer may be formed on the surface of the separation active layer, if necessary.

The types and combinations of the reactive compounds A and B used in the method for producing the composite hollow fiber membrane of the present invention, the types of the solvent constituting the first solution and the second solution used are the reactive compounds A and B. Any polymer may be used as long as it immediately undergoes a polymerization reaction at the interface to form a high molecular weight polymer thin film. Other than that, at least one of the reactive compounds A and B has three or more reactive groups. It is more preferable that a thin film made of a three-dimensional polymer is formed by including the reactive compound.

As the reactive compound A used in the present invention, a polyfunctional aromatic amine or a polyfunctional aliphatic amine can be used, for example, in the case of forming a polymer thin film made of a crosslinked polyamide. Examples thereof include polymers having a plurality of reactive amino groups such as polyethyleneimine, amine-modified polyepichlorohydrin and aminated polystyrene.

The polyfunctional aromatic amine is essentially an aromatic amino compound which is a monomer and has two or more amino groups in one molecule, and more specifically, m-phenylenediamine and p-. Phenylenediamine, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl ether, 3,4 '
-Diaminodiphenyl ether, 3,3'-diaminodiphenylamine, 3,5-diaminobenzoic acid, 4,4 '
-Diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 1,3,5, -triaminobenzene, 1,5-diaminonaphthalene, and the like, and these alone Alternatively, a mixture can be used. In the present invention, m-phenylenediamine and p-phenylenediamine are particularly preferably used.

The polyfunctional aliphatic amine is an aliphatic amino compound which is essentially a monomer and has two or more amino groups in one molecule, and more specifically, 1,3-diamino. Cyclohexane, 1,4-diaminocyclohexane, 4,4'-bis (paraaminocyclohexyl) methane, 1,3 (or 2,4) -bis- (aminomethyl)
Primary amines having a cyclohexane ring such as cyclohexane and 1,3,5-triaminocyclohexane, piperazine, 2-methylpiperazine, ethylpiperazine, 2,
Secondary amine having a piperazine ring such as 5-dimethylpiperazine, 1,3-bis (4-piperidyl) methane, 1,
Secondary amines having a piperidine ring such as 3-bis (4-piperidyl) propane and 4,4'-bipiperidine, 4-
Amines having both primary and secondary amino groups such as (aminomethyl) piperidine, and further ethylenediamine, propylenediamine, 1,2-propanediamine,
1,2-diamino-2-methylpropane, 2,2-dimethyl-1,3-propanediamine, tris (2-aminoethyl) amine, N, N'-dimethylethylenediamine, N, N'-dimethylpropanediamine, etc. These can be used alone or in a mixture, and a mixture with the above-mentioned polyfunctional aromatic amine can also be used. It may also be an amide prepolymer composed of these. In the present invention, piperazine, 4- (aminomethyl) piperidine, ethylenediamine and 1,2-diamino-2-methylpropane are particularly preferably used.

Examples of the reactive compound B used in the present invention include polyfunctional aromatic acid halides and polyfunctional aliphatic acid halides when forming a polymer thin film made of crosslinked polyamide. In addition, it may be a bifunctional or higher functional compound capable of reacting with the polyfunctional amine to form a polymer.

The polyfunctional aromatic acid halide is essentially an aromatic acid halide compound which is a monomer and has two or more acid halide groups in one molecule, and more specifically, trimesic acid halide, Trimellitic acid halide, isophthalic acid halide, terephthalic acid halide, pyromellitic acid halide, benzophenone tetracarboxylic acid halide, biphenyldicarboxylic acid halide, naphthalenedicarboxylic acid halide, pyridinedicarboxylic acid halide, benzenedisulfonic acid halide and the like, These may be used alone or in a mixture. In the present invention, particularly trimesic acid chloride alone, or a mixture of trimesic acid chloride and isophthalic acid chloride,
Alternatively, a mixture of trimesic acid chloride and terephthalic acid chloride is preferably used.

The polyfunctional aliphatic acid halide is essentially a monomer and is an aliphatic acid halide compound having two or more acid halide groups in one molecule, and more specifically cyclobutanedicarboxylic acid. Alicyclic polyfunctional acid halide compounds such as acid halide, cyclopentanedicarboxylic acid halide, cyclopentanetricarboxylic acid halide, cyclopentanetetracarboxylic acid halide, cyclohexanedicarboxylic acid halide, cyclohexanetricarboxylic acid halide, or propanetricarboxylic acid halide, butane Examples thereof include tricarboxylic acid halides, pentanetricarboxylic acid halides, succinic acid halides, glutaric acid halides, and the like, which may be used alone or in a mixture thereof, and are further mixed with the polyfunctional aromatic acid halide described above. It can be also used.

Further, as another example of the reactive compound B, ethylene diisocyanate, propylene diisocyanate, benzene diisocyanate, toluene diisocyanate, naphthalene diisocyanate, methylenebis (4
-Phenyl isocyanate) and the like.

The concentrations of these reactive compounds contained in the first solution and the second solution differ depending on the kind of the polyfunctional compound and the partition coefficient for the solvent, and are not particularly limited. As an example, an aqueous solution of piperazine is used as the first solution and an n-hexane solution of trimesic acid chloride is used as the second solution, the concentration of piperazine is about 0.1-1.
A content of 0% by weight, preferably about 0.5 to 5% by weight, is suitable, and a concentration of trimesic acid chloride is about 0.01 to 10% by weight, preferably about 0.1 to 5% by weight.
If the concentration of these is low, the formation of the interfacial polymerized film is incomplete and defects are likely to occur, leading to a decrease in separation performance.On the contrary, if the concentration is too high, the interfacial polymerized film becomes too thick and the permeation performance deteriorates. The amount of residual unreacted substances of (3) increases, which may adversely affect the membrane performance.

When an acid is generated during the progress of the interfacial polymerization reaction, an alkali as an acid scavenger is added to the first solution, and the wettability with the microporous hollow fiber support membrane is improved. Therefore, a surfactant may be added, or a catalyst for accelerating the reaction may be added if necessary. Examples of the acid scavenger include caustic alkali such as sodium hydroxide, sodium phosphate such as trisodium phosphate, sodium carbonate such as sodium carbonate, and tertiary amines such as trimethylamine, triethylamine and triethylenediamine. And the like. Examples of the surfactant include sodium lauryl sulfonate, sodium lauryl benzene sulfonate, sodium dodecyl benzene sulfonate, and the like, and examples of the catalyst include dimethylformamide and the like. These can be included in the first solution or the second solution in advance.

In the present invention, the first solution means a liquid containing a reactive compound with which the microporous hollow fiber support membrane comes into contact first, and the second solution reacts with the first solution to form an interface. It refers to a liquid containing a reactive compound that forms a high molecular polymer by a polymerization reaction. As the solvent of the first solution and the solvent of the second solution, those that dissolve the above-mentioned reactive compounds A and B, respectively, and form a liquid-liquid interface when the respective solutions come into contact with each other and do not damage the microporous hollow fiber support membrane It is not particularly limited as long as it is.
As such a solvent, for example, water is used as the solvent of the first solution,
The alcohol may be used alone or as a mixture, and as the solvent for the second solution, hydrocarbon solvents such as n-hexane, cyclohexane, n-heptane, n-octane, n-nonane, and n-decane may be used alone or as a mixture. it can.

In the present invention, the microporous hollow fiber support membrane is contacted with a first solution containing reactive compound A, followed by a first solution containing reactive compound B and which is substantially immiscible with the first solution. At the time of sequentially contacting with two solutions, at least the second solution is supplied to a container whose upper and lower sides are opened in slits,
The microporous hollow fiber supporting membrane is introduced into the container, and then it is moved in the vertical direction to bring the microporous hollow fiber supporting membrane into contact with the solution in the container. The reactive compounds A and B are reacted on the surface of the support membrane to form a polymer thin film to continuously produce the target composite hollow fiber membrane. Hereinafter, the production method of the present invention will be described.

FIGS. 1 and 2 show an example of a container according to the present invention, which is opened in the upper and lower sides in a slit shape. The solution containing the reactive compound A or B is supplied from the reaction solution feed port 6 into the container 2 opened in a slit shape, a part of the supplied reaction solution 3 flows down from the lower slit 5, and the remaining solution is It is discharged from the reaction solution discharge port 7 to the outside of the container. In order to realize such a flow of the reaction solution in the container 2 opened in a slit shape, it is preferable that the width of the slit is as narrow as possible or that the lower slit 5 is narrower than the upper slit 4 as illustrated in FIG. . The microporous hollow fiber support membrane 1 enters the container through the lower slit 5, contacts the reaction solution 3, and then is guided out of the container through the upper slit 4.

FIG. 3 and FIG. 4 are views showing an example of a method of bringing the microporous hollow fiber support membrane into contact with the reaction solution in a container opened in a slit shape. In FIG. 3, the solution 3 containing the reactive compound sent from the solution sending pipe 15 flows down in the container 2 having a slit-like opening, and the microporous hollow fiber support membrane 1 and the reaction solution 3 flowing down. Contact. Further, in FIG. 4, the solution 3 containing the reactive compound sent from the solution sending pipe 15 is supplied into the container 2 opened in a slit shape, and a part of the supplied reaction solution 3 is recovered from the lower slit. The solution flows down to the tank 11, and the remaining solution is returned to the solution storage tank 13 from the reaction solution discharge port through the solution recovery pipe 17. The microporous hollow fiber support membrane 1 comes into contact with the reaction solution 3 circulating in the container.

The moving direction of the microporous hollow fiber supporting membrane may be the same direction or the opposite direction with respect to the reaction solution 3 flowing down. However, in the case of contacting the second solution, in order to avoid contact with the guide roller immediately after the reaction, the moving direction of the microporous hollow fiber support membrane is in the opposite direction to the flowing solution containing the reactive compound. Is preferred. The shape and material of the container 2 having a slit-like opening are not particularly limited, but depending on the number of microporous hollow fiber support membranes passing through the container, the micropores may be formed in the container or at least one of the upper and lower ends thereof. It is also possible to provide one or more guides for separating the flexible hollow fiber support membrane. Further, the material of the container is not particularly limited as long as it does not dissolve in the solvent used and is not corroded by the compound used, for example, organic materials such as plastics, inorganic materials such as metals and ceramics, polymers such as metals and the like. Examples thereof include composite materials coated with. Of these, polyvinyl chloride, polyethylene, polypropylene, Teflon, stainless steel and the like are preferable. When the reaction solution and the microporous hollow fiber support membrane are in contact with each other, it is preferable that the microporous hollow fiber support membrane does not come into contact with the inner surface of the container opened in the slit shape from the viewpoint of the membrane forming operation. Presence or absence of contact between the yarn support film and the inner surface of the container is not particularly limited.

The width of the container opened in a slit shape can be arbitrarily selected depending on the size and number of the microporous hollow fiber supporting membranes used. Further, the length of the container in the vertical direction is preferably such that the desired impregnation or reaction can be sufficiently carried out, and further, it is desirable to take into consideration the moving speed of the microporous hollow fiber supporting membrane. When impregnating the microporous hollow fiber support membrane with the first solution by the apparatus of the present invention is insufficient, the conventional impregnation method is applied and the present invention is applied only when the second solution is contacted. It is also possible to use the device according to. After the first solution is impregnated, the excess solution remaining on the surface of the microporous hollow fiber support membrane is one of the causes of peeling of the separation active layer formed after the contact with the second solution. Therefore, remove the excess solution. However, a natural flow-down method, a natural air drying method, a drying method using hot air, or the like can be used.

It is desirable to collect and reuse the reaction solution that has flowed down, and it is preferable to provide a solution recovery tank 11 as illustrated in FIG. 3 or 4. For example, as shown in FIG. 3, the reaction solution 3 received in the solution recovery layer 11
Is collected in the solution storage tank 13 through the solution discharge port 12, the solution is sent to the solution sending pipe 15 by the solution sending pump 14, and is again supplied into the container 2 having a slit-like opening. It is available. Further, it is desirable that the supply of the reaction solution carried away by the microporous hollow fiber support membrane, the supply of the reactive compound consumed by the reaction, the temperature adjustment of the reaction solution, etc. be performed in the solution storage tank 13.

As described above, the microporous hollow fiber support membrane can be subjected to a pretreatment such as drying, hydrophilization treatment, impregnation with a packing agent, etc., if necessary. Further, the reactive compounds A and B
Reaction between the two, removal of residual solvent, reactive compounds A, B
It is desirable to dry or heat-treat the microporous hollow fiber support membrane after contact with the second solution, if necessary, for the purpose of fixing the separation active layer formed by the reaction between the two to the microporous hollow fiber support membrane. It is desirable to provide a device for this. It is also desirable to provide a step of providing a protective layer on the surface of the formed separation active layer, if necessary, and a step of washing to remove residual unreacted compounds and reaction by-products.

When a composite hollow fiber membrane is produced using the method of the present invention, the concentration, temperature or traveling speed of the microporous hollow fiber support membrane and the container opened in the shape of a slit depending on the properties of each liquid. The composite membrane suitable for the purpose can be obtained by setting the length, ie, the contact time with each liquid, the flow-down speed of each liquid, etc. to the optimum conditions.

The manufacturing process of the composite hollow fiber membrane according to the present invention will be described below with reference to the drawings. FIG. 5 shows an example of a composite film formation process in a schematic flow. The microporous hollow fiber support membrane 1 in the wet state is guided to the guide rollers 24, 24 'in the first solution tank via the guide rollers 21, 21'. The first solution tank 22 is filled with the first solution containing the reactive compound A prepared in advance. The first solution is impregnated by passing the microporous hollow fiber support membrane 1 through the first solution. Then, the microporous hollow fiber support membrane 1 is run in the air, and then introduced into the first drying tower 25 to remove the excess first solution. The microporous hollow fiber support membrane 1 that has passed through the first drying tower 25 has a guide roller 29,
29 ', a guide roller 35 in the second solution tank,
Guided to 35 '.

On this second solution tank, a second solution 37 containing a separately prepared reactive compound B is prepared from the second solution storage tank 31 containing the second solution 37 by using the second solution delivery pump 32.
Container 3 opened in a slit shape through the solution delivery pipe 34
6 and the second solution 37 is supplied to the container 3
It circulates within 6. In the second solution, the first
The microporous hollow fiber support membrane 1 in which the solution is impregnated is guided to start the reaction between the reactive compound A and the reactive compound B. Subsequently, after the microporous hollow fiber support membrane 1 was run in the air, it was introduced into the second drying tower 39 to remove a certain amount of the solvent forming the second solution, and the microporous hollow fiber support membrane 1 surface was formed. A separate active layer is formed. The composite hollow fiber membrane that has passed through the second drying tower 39 passes through the guide rollers 43, 43 'and is washed with water 44
It is guided into the washing water 45 inside, and after the residue is washed out, it is dried again in the third drying tower 47 and wound up by the winding machine 51. Although FIG. 5 shows an example in which the manufacturing method of the present invention is applied only to the second solution, it is also possible to apply the manufacturing method of the present invention to both the first solution and the second solution as described above. is there.

[0040]

EFFECTS OF THE INVENTION According to the method for producing a composite hollow fiber membrane of the present invention, a thin active separation layer comprising a polymer thin film can be continuously formed on the surface of a microporous hollow fiber support membrane. Therefore, high water permeability can be achieved. Further, when the high molecular polymer thin film is formed on the outer surface of the microporous hollow fiber support membrane, contact with the transfer means of the microporous hollow fiber support membrane such as a guide roll can be avoided, so that the formed thin film is Since there is no risk of peeling or damage and a uniform thin film can be continuously formed on the outer surface of the microporous hollow fiber support membrane, a composite hollow fiber membrane with excellent permeation performance and separation performance can be easily formed.
It is possible to manufacture stably. The composite hollow fiber membrane according to the present invention is, for example, softened water having high hardness, desalted from a solution containing a water-soluble organic substance having a molecular weight of 100 or more such as sugar or organic acid, desalted from a solution containing an amino acid, or an amino acid. Concentration of water, concentration / recovery of low-molecular-weight organic valuables in the food industry, water purification for the purpose of removing soluble substances in simple water facilities, wastewater treatment for the purpose of recovering industrial wastewater, etc. It can be suitably used for a membrane or a reverse osmosis membrane used for desalination by desalination of seawater or brackish water or for production of pure water for medical and electronic industries.

[0041]

The present invention will be described below with reference to examples and comparative examples, but the examples given here do not limit the present invention.

Reference Example 1 29 parts by weight of aromatic polysulfone (UDEL P-3500, manufactured by Amoco), 0.5 parts by weight of sodium laurylbenzenesulfonate, polyethylene glycol (molecular weight: 600
A film-forming solution consisting of 14.5 parts by weight and 56.0 parts by weight of DMAC was discharged from the tube-in-orifice nozzle into the coagulating bath through the running part in the air to obtain a microporous hollow fiber supporting membrane.

The microporous hollow fiber support membrane was thoroughly washed with water and then heat-treated at 90 ° C. for 1 hour. The obtained microporous hollow fiber support membrane had an outer diameter of 0.3 mm and an inner diameter of 0.2 mm, and the cross-sectional structure of this microporous hollow fiber support membrane had a dense layer on the inner and outer surfaces and other than that. Had a uniform network throughout. 20 microporous hollow fiber support membranes were bundled into a loop, one end of which was placed in a holder and hardened with an epoxy resin to open the microporous hollow fiber support membrane to prepare a mini module. This mini module was attached to an ultrafiltration membrane performance evaluation cell, and the dextran (molecular weight: 185,000) concentration in the feed solution: 500 mg / l, the feed solution temperature: 25 ° C, the operating pressure: 2 Kg / cm ²
When the ultrafiltration membrane performance was confirmed under these conditions, the dextran removal rate was 95.0%, and the permeated water amount was 1.0 m ³ / m ² · day · (kg / cm ² ). The dextran concentration in the feed water and the permeate was measured by the anthrone-sulfuric acid method, and the dextran removal rate was defined by the following equation. [1- (concentration of dextran in membrane permeate / concentration of dextran in source solution)] × 100 (%)

Example 1 A composite film was formed according to the steps shown in FIG. Using the microporous hollow fiber support membrane 1 prepared in Reference Example 1, the traveling speed is 7 m.
/ Min. The above microporous hollow fiber support membrane is placed in a first solution tank 22 containing an amine aqueous solution prepared by dissolving 2.0% by weight of piperazine, 0.5% by weight of triethylenediamine and 0.1% by weight of sodium laurylsulfonate in pure water. 1 was passed through to impregnate the above amine aqueous solution. These steps were performed at room temperature (about 25 ° C.). Subsequently, the microporous hollow fiber support membrane 1 was run in the air for 75 cm, and then introduced into a 2 m first drying tower 25 at 50 ° C. to remove excess amine water.

A second solution storage tank 31 containing a separately prepared TMC / n-hexane solution prepared by dissolving 1.0% by weight of trimesic acid chloride (hereinafter abbreviated as TMC) in n-hexane.
The second solution delivery pump 33 is used to supply the second solution through the second solution delivery pipe 34 into the container 36 having a height of 35 cm, which is opened in a slit shape.
A microporous hollow fiber support membrane having the above amine aqueous solution immersed therein was introduced. These steps were performed at room temperature (about 25 ° C.). Then, a microporous hollow fiber support membrane was placed at 50 ° C. for 2 m of second membrane.
After being introduced into the drying tower 39 to form a separation active layer made of piperazine-crosslinked polyamide, it was immersed in washing water (pure water at 25 ° C.) in the washing tank 44 for 1 minute to obtain a composite hollow fiber membrane.

The obtained composite hollow fiber membrane was mounted on a membrane performance evaluation cell, and the concentration of magnesium sulfate in the feed solution: 0.05%, the feed solution pH: 6.5, the feed solution temperature: 25 ° C., the operating pressure: 5 Kg / cm.
² 、 Recovery rate: When evaluated under the condition of 1%, the salt removal rate in the conductivity measurement of the permeate was 71.9%, and the amount of permeated water was
It was 1.0 m ³ / m ² · day. The salt removal rate in the conductivity measurement means the salt removal rate (%) = [1- (conductivity of permeated liquid) /
(Conductivity of supply liquid)] × 100.

Example 2 A semipermeable composite membrane was prepared in the same manner as in Example 1 except that 1,2-diamino-2-methylpropane was used instead of piperazine. When the obtained composite hollow fiber membrane was evaluated under the same conditions as in Example 1, the salt removal rate in the conductivity measurement of the permeated liquid was 84.6%, and the permeated water amount was 1.9 m ³ / m ² · day. .

Example 3 A semipermeable composite membrane was prepared in the same manner as in Example 1 except that 4-aminomethylpiperidine was used in place of piperazine. When the obtained composite hollow fiber membrane was evaluated under the same conditions as in Example 1, the salt removal rate in the conductivity measurement of the permeate was 77.2%, and the amount of permeated water was 1.2 m ³ /
It was m ² · day.

Comparative Example 1 In the process of FIG. 5, the second solution was not used in the slit-shaped container according to the present invention, and the conventional method by the dipping method was used as in the case of contacting the first solution. The hollow fiber support membrane was contacted with the second solution. The microporous hollow fiber support membrane prepared in Reference Example 1 was used, and the traveling speed was 7 m / min. A microporous hollow fiber support membrane was placed in a first solution tank containing an amine aqueous solution prepared by dissolving 2.0% by weight of piperazine, 0.5% by weight of triethylenediamine and 0.1% by weight of sodium laurylsulfonate in pure water for 1 minute. After the immersion, the microporous hollow fiber support membrane was run in the air for 75 cm to remove excess amine water.

Separately prepared 1.0% by weight of trimesic acid chloride (hereinafter abbreviated as TMC) in a second solution tank adjusted to 20 ° C. containing a TMC / n-hexane solution dissolved in n-hexane was used for 10 seconds. After guiding the microporous hollow fiber supporting membrane impregnated with an aqueous amine solution, the microporous hollow fiber supporting membrane was introduced into a second drying tower of 2 m at 50 ° C. to form a separation active layer composed of piperazine-crosslinked polyamide. After that, the composite hollow fiber membrane was obtained by immersing in washing water (pure water at 25 ° C.) in the washing tank for 1 minute.

The obtained semipermeable hollow fiber composite membrane was mounted in a membrane performance evaluation cell, and the concentration of magnesium sulfate in the feed solution was 0.05.
%, Feed liquid pH: 6.5, feed liquid temperature: 25 ° C, operating pressure:
When evaluated under the conditions of 5 kg / cm ² and recovery rate: 1%, the salt removal rate in the conductivity measurement of the permeate was 21.1%, and the permeated water amount was 0.7 m ³ / m ² · day. Compared to Example 1, the separation performance, that is, the salt removal rate was low. When the surface of the obtained composite hollow fiber membrane was observed with an electron microscope, peeling of the separation active layer was observed. In this method,
In the second solution tank containing the TMC / n-hexane solution,
It is presumed that the formed separation active layer was peeled off because the interfacial polymerized film was formed on the outer surface of the microporous hollow fiber supporting membrane and the guide roller and the outer surface of the microporous hollow fiber supporting membrane were in contact with each other. It

[Brief description of drawings]

FIG. 1 shows an example of a slit-shaped container used in the method for producing a composite film of the present invention.

FIG. 2 shows an example of another form of the slit-shaped container used in the method for producing a composite membrane of the present invention.

FIG. 3 shows an example of an apparatus for contacting a reaction solution in a slit-shaped container with a microporous hollow fiber support membrane used in the method for producing a composite membrane of the present invention.

FIG. 4 shows an example of another device used in the method for producing a composite membrane of the present invention, which brings the microporous hollow fiber support membrane into contact with the reaction solution in the slit-shaped container.

FIG. 5 shows an example of a schematic flow of an apparatus used in the method for producing a composite membrane of the present invention.

[Explanation of symbols]

 1. Microporous hollow fiber support membrane 1. Container with slit-shaped opening 3. Reaction solution 4. Upper slit 5. Lower slit 6. Reaction solution feed port 7. Reaction solution outlet 11. Solution recovery tank 12. Solution outlet 13. Solution storage tank 14. Liquid delivery pump 15. Liquid transfer pipe 16, 16 '. Guide roller 17. Solution recovery pipe 21, 21 '. Guide roller 22. First solution tank 23. First solution 24, 24'. Guide roller 25. First drying tower 26. First drying tower inlet 27. First drying tower outlet 28,28 '. Guide roller 29,29'. Guide roller 30. Second solution recovery tank 31. Second solution storage tank 32. Solution outlet 33. Second solution delivery pump 34. Second solution delivery pipe 35,35 '. Guide roller 36. Slit-shaped container 37. Second solution 38. Second solution recovery pipe 39. Second drying tower 40. Second drying tower inlet 41. Second drying tower outlet 42,42 '. Guide roller 43,43'. Guide roller 44. Wash tank 45. Water 46,46 '. Guide roller 47. Third drying tower 48. 3rd drying tower entrance 49. Third drying tower outlet 50,50 '. Guide roller 51. Winding machine

Claims (6)

[Claims] 1. A first solution containing at least one reactive compound A when obtaining a composite membrane in which a separation active layer made of a polymer thin film is provided on the surface of a microporous hollow fiber support membrane, A second solution containing at least one reactive compound B capable of reacting with the reactive compound A to form the high molecular weight polymer thin film, which is substantially immiscible with the first solution, is successively added to the fine solution. The porous hollow fiber support membrane is brought into contact with the surface of the microporous hollow fiber support membrane to carry out an interfacial polymerization reaction which produces a high molecular polymer by the reaction of the reactive compounds A and B to form a continuous composite membrane. In the method for producing, in contacting the microporous hollow fiber support membrane with the first solution and subsequently with the second solution, at least the second solution is supplied to a container having upper and lower openings in a slit shape, Guide the microporous hollow fiber support membrane into the container and draw A method for producing a composite hollow fiber membrane, characterized in that the microporous hollow fiber support membrane and the solution in the container are brought into contact with each other by continuously passing this through the vertical direction. 2. The method for producing a composite hollow fiber membrane according to claim 1, wherein the solution supplied to the container having the upper and lower slit-shaped openings is only the second solution. 3. The method for producing a composite hollow fiber membrane according to claim 1, wherein the microporous hollow fiber support membrane is formed of a polysulfone resin. 4. The method for producing a composite hollow fiber membrane according to claim 1, wherein the high molecular weight polymer thin film is a crosslinked polyamide. 5. A first solution containing at least one reactive compound A when obtaining a composite membrane in which a separation active layer made of a polymer thin film is provided on the surface of a microporous hollow fiber support membrane, A second solution containing at least one reactive compound B capable of reacting with the reactive compound A to form the polymer thin film, which is substantially immiscible with the first solution, A continuous composite membrane is obtained by bringing the microporous hollow fiber support membrane into contact and performing an interfacial polymerization reaction on the surface of the microporous hollow fiber support membrane to generate a high molecular polymer by the reaction of the reactive compounds A and B. In contacting the microporous hollow fiber support membrane with the first solution and subsequently contacting the second solution, at least the second solution is supplied to a container having slit-like upper and lower openings. And guide the microporous hollow fiber support membrane into the container. An apparatus for producing a composite hollow fiber membrane, which further comprises a step of bringing the microporous hollow fiber support membrane into contact with the solution in the container by successively passing it through in the vertical direction. 6. A first solution containing at least one reactive compound A when obtaining a composite membrane in which a separation active layer made of a polymer thin film is provided on the surface of a microporous hollow fiber support membrane, A second solution containing at least one reactive compound B capable of reacting with the reactive compound A to form the polymer thin film, which is substantially immiscible with the first solution, A continuous composite membrane is obtained by bringing the microporous hollow fiber support membrane into contact and performing an interfacial polymerization reaction on the surface of the microporous hollow fiber support membrane to generate a high molecular polymer by the reaction of the reactive compounds A and B. In the method for producing a microporous hollow fiber supporting membrane, the microporous hollow fiber supporting membrane is contacted with the first solution and then with the second solution.
After being brought into contact with the solution, the microporous hollow fiber support membrane is subsequently introduced into a container, in which the second solution is supplied, which is opened in the upper and lower slits, and then passed through the container in the vertical direction. An apparatus for producing a composite hollow fiber membrane, comprising a step of bringing the microporous hollow fiber support membrane into contact with the second solution in the container.