JPH08281085A - Composite hollow fiber membrane and its production - Google Patents

Abstract

PURPOSE: To obtain a high-performance composite hollow fiber membrane by including a fluorine compd. in the composite hollow fiber membrane consisting of a porous hollow fiber membrane and polyamide polymer thin films. CONSTITUTION: A second soln. 2 and a third liquid 3 are brought into contact with the outside surfaces of the porous hollow fiber membrane 4 and at this time, the contact is executed like the second soln. < the third liquid by a difference in sp. gravity. The third liquid 3 contg. a fluorine compd. is fed into a soln. vessel 5 and the second soln. 2 is fed from above so as not to exceed a partition 6. After the porous hollow fiber membrane 4 is immersed into a first soln. 1, the membrane enters the second soln. 2 nearly perpendicular from above the soln. where an interfacial polymn. reaction takes place and the polymer thin films are formed on the porous hollow fiber membrane 4. The membrane thereafter passes the boundary S1 between the second soln. 2 and the third liquid 3 and passes the inside of the third liquid 3. The fluorine compd. is then included in the hollow fiber membrane 4 and the thin films are uniformly, continuously and stably formed on the outside surfaces of the porous hollow fiber membrane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multifilament membrane useful as a reverse osmosis membrane or a nanofiltration membrane and a method for producing the same. More specifically, it relates to a composite hollow fiber membrane obtained by forming a thin film polymer having selective permeability on the outer surface of a porous hollow fiber membrane by a so-called interfacial polymerization method. The composite hollow fiber membrane thus obtained enables desalination of seawater, desalination of canned water, recovery of valuable substances in aqueous solution, wastewater treatment, and removal of impurities in water.

[0002]

2. Description of the Related Art A second solution containing one polyfunctional compound A capable of reacting with each other to form a polymer and another polyfunctional compound B and immiscible with the first solution. In sequence,
A so-called interfacial polymerization technique for forming a thin film by bringing a porous support membrane into contact with each other and causing the polyfunctional compounds to react with each other on the porous support membrane to form a thin film is a reverse osmosis membrane. For example, U.S. Pat.No. 3,744,642,
No. 4,039,440, No. 4,259,183, No. 4,277,344, JP-A-55-147106, JP-A-49-133282. , Tokkyo 1-38
No. 522, etc. are known. When these methods are applied to the outer surface of the porous hollow fiber membrane as they are, the interfacial polymerized membrane is contacted with a transfer means such as a roller during or immediately after the formation of the interfacial polymerized membrane on the outer surface of the porous hollow fiber membrane. Inevitably, the formed thin film peels off or is damaged, resulting in a film defect. Therefore, it is not possible to stably and continuously obtain a high-performance composite hollow fiber membrane having a uniform thin film having no membrane scratches.

On the other hand, in the case of a composite hollow fiber membrane, US Pat.
4,980,061, Japanese Patent Laid-Open No. 62-95105,
In JP-A-60-87807, a porous hollow fiber membrane is passed through an interface formed by contacting the first solution and the second solution to form a polymer thin film on the outer surface of the porous hollow fiber membrane. The forming technique is shown. See also PB Report 81-1
In 67215, the porous hollow fiber membrane is continuously immersed in a piperazine aqueous solution bath and an acid chloride cyclohexane solution bath,
A composite hollow fiber membrane obtained by passage and a method for producing the same are shown. Further, JP-A-2-2842 shows an example of a composite hollow fiber membrane in which a crosslinked polyamide is formed on the surface of the porous hollow fiber membrane, and as a method for producing the same, a thin film is formed on the outer surface of the porous hollow fiber membrane. In the case of forming a compound, a porous hollow fiber membrane is impregnated with a polyfunctional amine solution, air-dried, and then immersed in a polyfunctional acid chloride solution. Further, Japanese Patent Laid-Open No. 6-114246 discloses a manufacturing method in which a tank provided with a weir or a hole for allowing a porous hollow fiber membrane to come in and out is used as a tank for immersing in the second solution.

[0004]

In the conventional method for producing a composite hollow fiber membrane by the interfacial polymerization method, the porous hollow fiber membrane is passed through the interface formed by bringing the first solution and the second solution into contact with each other to form a porous structure. Of forming a polymer thin film on the outer surface of a porous hollow fiber membrane (US Pat. No. 4,980,061; JP-A-62-95)
No. 105, JP-A-60-87807),
The thin film formed on the outer surface of the porous hollow fiber membrane is dried or transferred to the heat treatment step without contacting the means for transferring the porous hollow fiber membrane such as a roller during or immediately after the formation, and the thin film porous hollow fiber membrane is transferred. Can be fixed to However, since the polymerized membrane formed in a flat shape at the interface is laminated on the porous hollow fiber membrane having a curved surface, it is not possible to uniformly form a thin film on the outer surface of the porous hollow fiber membrane. In addition, since the polymer thin film formed at the interface is simply laminated on the porous hollow fiber membrane, the adhesion between the porous hollow fiber membrane and the thin film becomes low, and the porous thin film after being immersed in the first solution is porous. Inability to introduce a step of removing or drying the excess amine solution adhering to the porous hollow fiber membrane, and further, the polymer thin film formed at the interface between the two solutions, which is not accompanied by the porous hollow fiber membrane, is the elapsed time. Along with the increase in thickness, which may hinder the formation of a polymer thin film on the outer surface of the porous hollow fiber membrane, it is difficult to form a continuous and uniform thin film on the outer surface of the porous hollow fiber membrane, etc. Due to the problem, a composite hollow fiber membrane having high permeation performance and separation performance has not been obtained at present.

On the other hand, the PB Report 81-16721
In the manufacturing method in which the porous hollow fiber membrane is continuously immersed in and passed through the two solution baths shown in 5, a specific manufacturing process is not shown, but a thin film is being formed as in the case of the flat membrane described above. Or it is presumed that the thin film was damaged by the roller etc. immediately after the formation, and the variation of the data was large.
Separation performance is also low. Similarly, in the production method of dipping in the polyfunctional amine solution and the polyfunctional acid chloride solution disclosed in JP-A-2-2842, the production method itself is not clear because a specific production process is not shown. , The air-drying step is simply inserted and the dipping step is repeated, and this is not substantially different from the example of the case of the flat membrane, and the obtained composite hollow fiber membrane has only low performance. Has not been done. It is presumed that a similar problem would occur when applied to a continuous porous hollow fiber membrane. The present invention is intended to eliminate such drawbacks, and by forming a thin film continuously and uniformly on the outer surface of the porous hollow fiber membrane, a composite hollow fiber membrane having excellent permeation performance and separation performance, and It is intended to provide a manufacturing method thereof.

[0006]

As a result of earnest research in view of the above object, the present inventors have found that a high-performance composite hollow fiber membrane can be obtained by incorporating a fluorine compound into the composite hollow fiber membrane. As a result, the above-mentioned object was achieved. Furthermore, the following method was found as a method of containing this fluorine compound and continuously and stably forming a thin film on the outer surface of the porous hollow fiber membrane, and arrived at the present invention. That is, the porous hollow fiber membrane comprises a fluorine compound that is substantially immiscible with the second solution and is capable of forming an interface with the second solution after being contacted vertically from the first solution to the second solution. This is a method of contacting the third liquid. Another method is to contact the porous hollow fiber membrane from the first solution to a third solution containing a fluorine compound and then to a second solution. Both of the second solutions are substantially immiscible and each can form an interface. By introducing these novel methods, it becomes possible to include a fluorine compound in the composite hollow fiber membrane, and further it is possible to carry out an interfacial polymerization reaction only on the outer surface of the porous hollow fiber membrane, and Immobilize the thin film on the porous hollow fiber membrane by transferring it to the drying, heat treatment step, and if necessary alkali treatment step so that it does not come into contact with the porous hollow fiber membrane transfer means such as rollers during and / or immediately after the thin film formation. I found that it is possible. This is a conventional type in which a polymer thin film interfacially polymerized at the interface between a first solution and a second solution is laminated on a porous hollow fiber membrane,
The technical idea is completely different from that of passing the porous hollow fiber membrane through the first solution tank and the second solution tank. Further, this third liquid scrapes off the excess first solution adhering to the surface of the porous hollow fiber membrane, and continuously contacts the second solution with the liquid film thickness of the first solution being controlled to cause an interfacial reaction. It was found that the composite hollow fiber membrane can be produced, and the composite hollow fiber membrane having excellent permeation performance and separation performance can be produced, and the present invention has been completed.

That is, the present invention has the following configuration. (1) A composite hollow fiber membrane comprising a porous hollow fiber membrane and a polyamide polymer thin film coating the outer surface of the porous hollow fiber membrane, wherein the composite hollow fiber membrane contains a fluorine compound. And a composite hollow fiber membrane. (2) The method for producing a composite hollow fiber membrane according to (1) above, which has at least two reactive amino groups and is at least 1
A first solution containing a polyfunctional compound A of one kind and a second solution containing a polyfunctional compound B of at least one kind of a polyfunctional acid halide and substantially immiscible with the first solution.
In order to produce a continuous composite hollow fiber membrane by sequentially contacting the solution with a porous hollow fiber membrane and interfacially polymerizing the polyfunctional compounds A and B with each other on the porous hollow fiber membrane to form a thin film. The porous hollow fiber membrane from the first solution to the second
A method for producing a composite hollow fiber membrane, which comprises contacting with a solution and then contacting at least one location with a third solution which is substantially immiscible with the second solution and which contains a fluorine compound. (Hereinafter, it is abbreviated as Production Method I.) (3) Another production method of the composite hollow fiber membrane according to (1) above, which has at least one reactive amino group and is composed of at least one type. A first solution containing the functional compound A,
A porous hollow fiber membrane is sequentially contacted with a second solution that contains at least one polyfunctional compound B consisting of a polyfunctional acid halide and is substantially immiscible with the first solution. In producing a continuous composite hollow fiber membrane by forming a thin film by interfacially polymerizing the polyfunctional compounds A and B on the fiber membrane, the porous hollow fiber membrane is continuously treated from the first solution. It is characterized in that, while being contacted with the second solution, it is substantially immiscible with both the first solution and the second solution and is contacted with at least one location of the third solution containing a fluorine compound. Method for producing composite hollow fiber membrane. (Hereinafter abbreviated as production method II.)

In the present invention, the porous hollow fiber membrane is a supporting membrane for supporting the above-mentioned polymer thin film, which does not substantially show separation performance for the object to be separated, and is a conventionally known porous hollow fiber membrane. Any material may be used, but its outer surface is preferably 0.1 μm or less, more preferably 0.05 μm.
It is preferable that the structure having fine pores of m or less and having a pore size larger than the fine pores on the outer surface is used in order to prevent the fluid permeation resistance from unnecessarily increasing in the structure from the outer surface to the back surface. It may be a void or a mixed structure thereof. As an example of the permeation performance, in the case of a high pressure reverse osmosis membrane that can be used for seawater desalination, the permeation rate per unit pressure and unit area is, for example, 0.01 to 0.2 m ³ / (m ² · day ・(kg / c
m ² )), preferably 0.02-0.1 m ³ / (m ² · day · (kg / c
m ² )), in the case of a low pressure reverse osmosis membrane used at 15 kg / cm ² or less, 0.2 to ¹⁰ m ² / (m ² · day · (kg / cm ² ))), preferably 0.5 to 5m ³ / (m ² · day · (kg / cm ² )), in the case of a so-called nanofiltration membrane used at low pressure, for example, 0.5 to 50m ³
/ (m ² · day · (kg / cm ² )), preferably 1 to 20 m ³ / (m ² · day ·
(kg / cm ² )). If the amount of water permeation is too small, the permeation performance of the obtained composite membrane will be small, and if it is too large, the strength of the supporting membrane will be small and the porous hollow fiber membrane may be destroyed depending on the operating pressure.

Any material can be used as long as it can be formed into a porous hollow fiber membrane. However, it is necessary that the membrane structure is not damaged by dissolution or decomposition when contacted with the first solution, the second solution, and the third solution. For example, when the first solution, the second solution, and the third solution are amine and acid scavenger aqueous solutions, acid chloride hexane solutions, and fluorine-based inert liquids, polysulfone, polyether sulfone, polyacrylonitrile, polyethylene, polypropylene, It is preferable to have at least one selected from polyamide as a main component, and more preferable to have at least one selected from polysulfone and polyethersulfone as a main component.

The size is not particularly limited, but in consideration of operability during film formation, the film area of the module, and pressure resistance, the outer diameter is 1
00 (μm) to 2000 (μm), inner diameter 30 (μm)
To 1800 (μm) are preferable, and the outer diameter is 1
50 (μm) to 500 (μm), inner diameter 50 (μm) to
300 (μm) is more preferable. Furthermore, it is necessary to withstand at least a pressure higher than the operating pressure of the composite membrane. Although such a porous hollow fiber membrane can be selected from various commercially available materials, it can usually be produced by a known dry-wet film forming method or melt film forming method. Further, if necessary, the porous hollow fiber membrane after membrane formation is subjected to wet heat treatment at 50 ° C. as disclosed in JP-A-58-199007, or disclosed in JP-A-60-190204. As described above, hot water treatment at 90 ° C. or higher may be performed. 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 polymer thin film is a polyamide polymer thin film obtained by an interfacial polymerization method, and contains a polymer having a so-called amide bond as a main component. For example, in the case of a reverse osmosis membrane, a crosslinked polyamide membrane obtained by an interfacial polycondensation reaction of a polyfunctional amine and a polyfunctional acid halide may be mentioned. The thinner the pinhole is, the more preferable it is. Considering film forming stability, permeation performance and the like, the thickness is preferably 0.5 μm or less, more preferably 0.2 μm or less. A protective layer may be formed on the surface of the separation active layer, if necessary.

The fluorine compound contained in the composite hollow fiber membrane of the present invention is preferably a perfluoro compound or a compound having a perfluoroalkyl group. It is not clear that a uniform thin film can be formed by containing these in the composite hollow fiber membrane, and that high permeation performance and high separation performance can be obtained, but these are generally low dielectric constant, low surface tension, low refractive index. It is considered that the thin film is formed in a uniform dispersed state by being present during or immediately after the thin film formation, and as a result, a uniform and defect-free thin film can be continuously and stably formed. .

The content of this fluorine compound is
It is present in the surface of the polymer thin film which is the separation active layer, inside, between the polymer thin film and the porous hollow fiber membrane, in the porous hollow fiber membrane, etc., and may be contained in the composite hollow fiber membrane. It does not matter where it is located. However, these do not exist by being chemically bonded to the polymer forming the thin film and / or the porous hollow fiber membrane. Even if the content of this fluorine compound is very small, the above effect can be sufficiently obtained, but if the content is too large, the effect of the hydrophobicity of the fluorine compound becomes large and the water permeability decreases, so a dry composite hollow fiber membrane is obtained. The amount of fluorine (F) per unit weight is preferably 1 ppm or more and 1000 ppm or less.

Next, a method for manufacturing the composite hollow fiber membrane will be described. The type and combination of the polyfunctional compounds A and B used in the method for producing the composite hollow fiber membrane of the present invention, the type of the solvent constituting the first solution and the second solution used are the polyfunctional compounds A and B. The comrades immediately initiate a polymerization reaction at the interface,
Any material can be used as long as it can produce a polyamide polymer, and other materials are not particularly limited. An example will be described below.
Examples of the polyfunctional compound A include aromatic amines and aliphatic amines, and any of them may be used.

The aromatic amine is an aromatic amine having two or more amino groups in one molecule, and the bifunctional or higher amines are, for example, m-phenylenediamine and p-.
Phenylenediamine, 4,4-diaminodiphenylamine, 4,4'-diaminodiphenyl ether, 3,4 '
-Diaminodiphenyl ether, 3,3'-diaminodiphenylamine, 3,5-diaminobenzoate, 4,
4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 1,3,5-triaminobenzene and the like are mentioned, and a mixture thereof may be used. Among them, m-phenylenediamine is most preferable. The aliphatic amine may be any bifunctional or higher amine, and specific examples thereof include piperazine, 2-methylpiperazine, ethylpiperazine, 2,5-dimethylpiperazine, homopiperazine, t-2,5-dimethylpiperazine. Derivatives such as bis (4-piperidyl) methane, 1,2-
Bis (4-piperidyl) ethane, 1,3-bis (4-piperidyl) propane, N, N′-dimethylethylenediamine, ethylenediamine, propylenediamine, propylenetriamine, N, N′-dimethylpropanediamine, 4- (aminomethyl) ) Piperidine, cyclohexanediamine, etc., and may be a mixture thereof or an amide prepolymer composed of them.

Examples of the polyfunctional compound B include polyfunctional acyl halides, which may be aromatic or aliphatic, and which may react with the polyfunctional amine to form a polymer. The above is sufficient. Aromatic or alicyclic bifunctional or trifunctional acid halides are preferable, for example, trimesic acid halide, trimellitic acid halide, pyromellitic acid halide, benzophenone tetracarboxylic acid halide, isophthalic acid halide, terephthalic acid halide, diphenyldicarboxylic acid halide. , Naphthalenedicarboxylic acid halide, benzenedisulfonic acid halide, chlorosulfonylisophthalic acid halide, pyridinedicarboxylic acid halide, 1,3,5-cyclohexanetricarboxylic acid halide, and the like. Considering reverse osmosis membrane performance and the like, trimesic acid chloride, isophthalic acid chloride, terephthalic acid chloride, and mixtures thereof are preferable. Here, each of the polyfunctional compounds A and B is not limited to one kind of compound, and a plurality of polyfunctional compounds of the same group that perform the same reaction can be used simultaneously depending on the purpose. Usually, each polyfunctional compound is often composed of three or less kinds.

The concentration of these polyfunctional compounds varies depending on the type of polyfunctional compound and the partition coefficient for the solvent. As an example, a piperazine aqueous solution is used as the first solution, and an n-hexane solution of trimesic acid chloride is used as the second solution. The piperazine concentration is about 0.1 to 10% by weight, preferably about 0.5 to 5% by weight is suitable, and the concentration of trimesic acid chloride is about 0.01 to 10% by weight, preferably about 0.1 to 5% by weight.
The ones are suitable. If the concentration of these is low, the formation of the interfacial polymer film is incomplete and defects are likely to occur, leading to deterioration of the separation performance. It is possible that the amount of residual unreacted substances of (3) increases and the membrane performance is adversely affected.

When an acid is generated in the condensation reaction, an alkali as an acid scavenger is added to the aqueous solution, or a surfactant is added to improve wettability with the porous hollow fiber membrane. In addition to this, a reaction accelerator of a polyfunctional compound may be added as necessary. Examples of the acid scavenger include caustic alkali such as sodium hydroxide, sodium phosphate such as trisodium phosphate, pyridine, triethylenediamine, triethylamine, sodium tertiary amine acetate, and the like. Examples include sodium lauryl sulfonate, sodium lauryl benzene sulfonate, and the like, and examples of the reaction accelerator include dimethylformamide (DMF) and the like. These can be contained in the first solution and / or the second solution in advance.

In the present invention, the first solution refers to a liquid containing a polyfunctional compound with which the porous hollow fiber membrane comes into contact first, and the second solution reacts with the first solution to allow interfacial polymerization. Of liquid. The liquid here is a solution in which a polyfunctional compound is dissolved in a solvent, and if the polyfunctional compound is a liquid monomer, the polyfunctional compound itself may be used.
As the solvent here, a mixture of a plurality of solvents may be used for the purposes of solubility of the polyfunctional compound, adjustment of the specific gravity of the liquid, adjustment of the formation state of the liquid-liquid interface, and the like.

As the solvent of the first solution and the solvent of the second solution, the polyfunctional compounds A and B are dissolved, respectively, and when each solution comes into contact, a liquid-liquid interface is formed and the porous hollow fiber membrane is not damaged. It is not particularly limited as long as it is one. For example, when the polyfunctional compound A is a polyfunctional amine and the polyfunctional compound B is a polyfunctional acid halide, water is used as the solvent of the first solution and n-hexane or cyclohexane is used as the solvent of the second solution. , N-heptane, n-octane, n-nonane, n-
Hydrocarbon-based solvents such as decane and n-undecane are examples.

In the present invention, the third liquid is not particularly limited as long as it is a liquid which is substantially immiscible with the second solution in the case of the production method I, but the magnitude relationship of the specific gravities is the second because of the ease of the apparatus.
Solution <3rd solution is good. Further, a liquid that is substantially immiscible with both the first solution and the second solution is preferable. In the case of the production method II, the third liquid is not particularly limited as long as it is a liquid that is substantially immiscible with both the first solution and the second solution. Such a third liquid needs to be set by a combination of the first solution and the second solution, and may be a mixture of a plurality of liquids for adjusting fluidity, freezing point, specific gravity and the like. The immiscibility here means that there is no compatibility or there is some compatibility, but phase separation occurs even when a solution is mixed and an interface is formed between two liquids. The lower the solubility between the liquids, the better, and the dissolution amount at room temperature (15 to 25 ° C.) is preferably 10% by weight or less, more preferably 5% by weight or less. Further, the fact that the third liquid is substantially immiscible with the first solution and the second solution is substantially immiscible with each solvent of the first and second solutions, and the first and second It means that the polyfunctional compounds A and B dissolved in the solution are substantially immiscible with each other, and no reaction occurs.

Specific examples of the third solution include the first solution and the second solution.
When the solution is an aqueous solution of piperazine or an n-hexane solution of trimesic acid chloride, a fluorine-based inert liquid, particularly a perfluoro compound or a compound having a perfluoroalkyl group, may be used. These may be amines, ethers, unsaturated compounds, aromatic compounds, and aliphatic compounds as long as they satisfy the above characteristics, and preferable examples thereof include the following perfluoroalkyl tertiary amines. .

[0023]

Embedded image (In the formula, Ra, Rb and Rc each represent a perfluoroalkyl group having 4 to 6 carbon atoms, and the total number of carbon atoms is 14 to
Sixteen. )

More specifically, Fluorinert FC-70 manufactured by Sumitomo 3M Limited may be mentioned. The fluorine-based inert liquid FC-70 is mainly composed of C _n F _{2n + 3} N, consisting of n = 15 structure. The solubility between the three components of the fluorine-based inert liquid FC-70, water as the solvent of the first solution and n-hexane as the solvent of the second solution is n-
The amount of water dissolved in hexane is 0.014% by weight (1
5.5 ° C., Solvent Handbook (Kodansha)), the amount of water dissolved in this fluorine-based inert liquid FC-70 is 0.00
08% by weight (25 ° C, Fluorinert catalog), the amount of n-hexane dissolved in this fluorine-based inert liquid FC-70 is 1% by weight or more and less than 5% by weight (25 ° C, Fluorinert catalog, measured by the inventors). About 3% (23 ℃))
Is. In addition, piperazine and trimesic acid chloride show almost no solubility in this fluorine-based inert liquid FC-70. In addition to this, similarly, Fluorinert FC-71 manufactured by Sumitomo 3M Limited can be preferably used. In addition to this, when cyclohexane is used as the solvent of the second solution, FC-84, FC-, in addition to Fluorinert FC-70, FC-71 manufactured by Sumitomo 3M Limited.
77, FC-75, FC-40, FC-43 and the like can be used.

The temperatures of the first solution, the second solution, and the third solution are not particularly limited, but in the case of a combination of polyfunctional compounds in which an interfacial reaction occurs at room temperature sufficiently quickly, it is about room temperature in operation, that is, 5 A range of ~ 35 ° C is used. If the temperature is too high, deterioration of the polyfunctional compound may be accelerated,
There is a problem that the evaporation of the solvent is accelerated, and conversely if it is too low,
Impregnation of the porous hollow fiber membrane with the first solution is insufficient, the interfacial reaction rate becomes too small to form a polymer thin film completely, and the viscosity of the solvent becomes too large, which interferes with the film forming process. give.

In the present invention, bringing each solution into contact with the porous hollow fiber membrane means immersing and passing the porous hollow fiber membrane in each liquid. Further, when passing through the interfaces of the first solution and the second solution, it is preferable to pass the liquids as perpendicularly as possible to the interfaces of the respective liquids in order to form a uniform thin film.

After the immersion in the first solution, the excess solution remaining on the surface of the porous hollow fiber membrane causes peeling of the thin film, so it is preferable to remove the excess solution. Examples of the removal method include a method in which a porous hollow fiber membrane is allowed to run in the air to spontaneously drop and dry, a method for scraping using a third liquid, other methods such as blowing air or an inert gas, and drying with a drier. To be After passing through the third liquid, it may be immersed in an aqueous solution of an acid scavenger for neutralization and termination of the reaction. Examples of acid scavengers include sodium phosphate such as trisodium phosphate, sodium carbonate and the like.

Hereinafter, in the production method I of the present invention, the parts in which the porous hollow fiber membrane is brought into contact with each solution and liquid will be shown as a model. FIG. 1 shows an example of the case where the second solution and the third solution are brought into contact with the outer surface of the porous hollow fiber membrane and the magnitude relationship of the specific gravities is second solution <third solution. The third liquid 3 is charged into the solution tank 5, and the partition 6
The second solution 2 is charged from above so as not to exceed the above. After soaking the first solution, the porous hollow fiber membrane 4 enters almost vertically from the upper part of the second solution 2, where an interfacial polymerization reaction occurs and a polymer thin film is formed on the porous hollow fiber membrane 4. Then, the second solution 2
Through the interface S1 between the third liquid 3 and the third liquid 3.
When an interfacial polymerization reaction does not occur with the third liquid 3, but the reaction between the polyfunctional compound A and the polyfunctional compound B remaining on the surface of the porous hollow fiber membrane immediately after contact with the third liquid continues. Is
Part of the third liquid is taken into the film. Porous hollow fiber membrane 4
Passes through the rollers 7 ′, 7 in the third liquid 3, exits from the upper portion of the third liquid 3 in a substantially vertical direction, and is immediately sent to a subsequent process such as a drying process. By using the third liquid in this method, when the porous hollow fiber membrane contacts the second solution, the porous hollow fiber membrane can easily pass almost perpendicularly to each liquid interface without contacting the rollers 7 ′, 7 and the like. it can.

When a volatile organic solvent is used for the second solution, it is preferable to make the surface area of the upper atmosphere open portion as small as possible. This prevents solvent evaporation as much as possible,
This is because the change in the concentration of the polyfunctional compound B is reduced and a stable composite hollow fiber membrane is produced, and at the same time, a clean working environment can be maintained. In order to reduce the surface area of the atmosphere open portion, a thin tubular material may be used, and a method of passing a porous hollow fiber membrane through it may be used.

As a matter of course, FIG. 1 describes the case of one porous hollow fiber membrane as a model, but at the same time 2
It is possible to easily treat more than one porous hollow fiber membrane, and the width of the solution tank 5 is set as necessary.

Further, as described above, the porous hollow fiber membrane may be subjected to a pretreatment such as drying, hydrophilization treatment, impregnation with a packing agent and the like, if necessary. In addition, the porous hollow fiber membrane 4 may be formed as necessary for the purpose of terminating the interfacial reaction between the residual unreacted polyfunctional compounds, removing the residual solvent, and fixing the polymer thin film to the surface of the porous hollow fiber membrane 4. Move to drying or heat treatment equipment. Drying or heat treatment conditions vary depending on the porous hollow fiber membrane material, the polymer thin film material to be formed, and the type of each liquid. For example, the porous hollow fiber membrane material is polysulfone, the polymer thin film is polyamide, and the first solution 1 Is a polyfunctional amine aqueous solution, second solution 2
Is 20 when n is a polyfunctional acid chloride solution in n-hexane.
C. to 100.degree. C. and 10 seconds to 20 minutes are preferable. Further, if necessary, a step of forming a protective agent layer on the surface of the formed polymer thin film by coating or the like may be provided. In addition, removal of residual unreacted compounds, removal of reaction by-products, and washing and treatment for neutralization are performed as necessary. Furthermore, the composite hollow fiber membrane after membrane formation may be subjected to a drying treatment, if necessary, and the present invention is not limited to either a dry preservation method or a wet preservation method.

When a composite hollow fiber membrane is produced according to the present invention, the concentration of each liquid, the temperature, the running speed of the porous hollow fiber membrane, the height of the layer of each liquid, and the porosity of each liquid depending on the properties of each liquid. By optimally setting the running distance of the high quality hollow fiber membrane, that is, the residence time, a composite hollow fiber membrane suitable for the purpose can be obtained.
The running speed of the porous hollow fiber membrane is 0.5 m / min to 2
0 m / min is possible, and it is possible to produce a composite hollow fiber membrane at this speed. In addition, as a matter of course, in the case of continuous operation for a long period of time, the polyfunctional compound is consumed as the interfacial reaction proceeds and the solution concentration changes. You may provide the means to adjust.

FIG. 2 shows a schematic flow of the composite film forming process. The outline of the steps will be described below. The porous hollow fiber membrane 4 in a wet state is taken out from the porous hollow fiber membrane supply tank 11 by the drive rollers 19 ′, 19 and further introduced into the first solution tank 10 via the drive rollers 9 ′, 9 and immersed therein. Subsequently, the porous hollow fiber membrane 4 to which the first solution 1 is attached and impregnated is pulled out from the first solution tank 10 almost vertically through the drive rollers 8 ′, 8. The excess first solution is removed during the subsequent air travel. It is possible to adjust the amount of the first solution attached to the first solution on the porous hollow fiber membrane 4 by adjusting the air travel distance. Then, the porous hollow fiber membrane 4 is introduced substantially vertically into the second solution 2 to cause an interfacial polymerization reaction on the outer surface of the porous hollow fiber membrane 4. Second
The liquid-liquid interface S1 between the solution 2 and the third liquid 3 is penetrated to form the third liquid 3
It is dipped in and is passed through the drive rollers 7 ', 7 to the third
The liquid 3 is withdrawn almost vertically. When the porous hollow fiber membrane 4 was brought into contact with the second solution, the porous hollow fiber membrane 4 was introduced into the drying cylinder 12 through the third liquid 3 and fixed to the porous hollow fiber membrane 4 without contacting the driving roller or the like. After that, the drive roller 13 ',
After being guided to the washing tank 14 via 13 and passing through the washing water 15 via the drive rollers 16 ′, 16, the composite hollow fiber membrane receiving tank 18 via the driving rollers 17 ′, 17
Be led to.

FIG. 3 shows an example in which, after passing through the third liquid, an aqueous solution of an acid scavenger was used for neutralization of the interfacial polymerization reaction product and terminal treatment of unreacted groups. The solvent of the first solution is water, the third
When the liquid is substantially immiscible with both the first solution and the second solution and forms an interface, the third liquid also forms an interface with the aqueous acid scavenger solution. When the specific gravity of the liquid is the second solution <the third liquid and the acid scavenger aqueous solution <the third liquid, the third liquid 3 is added to the solution tank 5
Then, the second solution 2 and the acid scavenger aqueous solution 20 are respectively charged from above so as not to exceed the partition 6. After soaking the first solution, the porous hollow fiber membrane 4 enters almost vertically from the upper part of the second solution 2, where an interfacial polymerization reaction occurs and a polymer thin film is formed on the porous hollow fiber membrane 4. Then, it passes through the interface S1 between the second solution 2 and the third liquid 3 and passes through the rollers 7 ′, 7 in the third liquid 3. After passing through the interface S2 between the third liquid 3 and the acid scavenger aqueous solution 20, neutralization and the like in the acid scavenger aqueous solution 20, and then exiting from the upper part of the acid scavenger aqueous solution 20 and immediately after the drying step and the like. Sent to the process. In this method, by using such a third liquid, a series of manufacturing steps of the composite hollow fiber membrane can be carried out very easily and reliably.

FIG. 4 shows an example in which the first solution is removed by the third solution after the first solution is dipped in order to remove the excess first solution on the surface of the porous hollow fiber membrane after the first solution is dipped. . The outline of the steps will be described below. As in the case of FIG. 2, the porous hollow fiber membrane 4 in the wet state is taken out from the porous hollow fiber supply tank 11 by the drive rollers 19 ′, 19 and further passed through the drive rollers 9 ′, 9 to the first solution tank 10 Introduce and soak. Subsequently, the porous hollow fiber membrane 4 to which the first solution 1 is attached and impregnated is pulled out from the first solution tank 10 almost vertically through the drive rollers 8 ′, 8. Subsequent third liquid tank 2
Excess first solution is removed in one pass. When the third liquid 3 is immiscible with the first solution 1, the surface of the first liquid solution to the porous hollow fiber membrane 4 can be adjusted by adjusting the running depth of the third liquid tank 21 without changing its concentration. It is possible to adjust the adhesion amount. The excess first solution removed from the outer surface of the porous hollow fiber membrane 4 can be easily discharged from the upper part of the third solution in the third solution tank 21. Then, the porous hollow fiber membrane 4 is introduced almost vertically into the second solution 2 to cause an interfacial polymerization reaction on the outer surface of the porous hollow fiber membrane 4. Second solution 2
And through the liquid-liquid interface S1 of the third liquid, and is pulled out almost vertically from the third liquid via the drive rollers 7 ′, 7. When the porous hollow fiber membrane 4 was brought into contact with the second solution, the porous hollow fiber membrane 4 was introduced into the drying cylinder 12 through the third liquid 3 without contacting the driving roller or the like, and the thin film was fixed to the porous hollow fiber membrane 4. After that, it is guided to the washing tank 14 via the drive rollers 13 ', 13 and passes through the washing water 15 via the drive rollers 16', 16 and then through the drive rollers 17 ', 17 to form a composite hollow. It is guided to the yarn film receiving empty tank 18.

The production method II used in the present invention is described below.
The difference from the manufacturing method I will be mainly described. First, a model is shown in which the porous hollow fiber membrane is brought into contact with each solution and liquid. When the second solution and the third solution are brought into contact with the outer surface of the porous hollow fiber membrane, the contact method differs depending on the specific gravity of each solution. FIG. 5 shows an example in which the magnitude relationship of the specific gravities is the case of the second solution <the first solution <the third solution. The third solution 3 is charged into the solution tank, the first solution and the second solution 2 are respectively charged from above so that the partition 6 is not exceeded, and the first solution 1 and the second solution 2 form a liquid-liquid interface between them. Do not install. The porous hollow fiber membrane 4 is the first solution 1
Soak and pass through. At this time, the porous hollow fiber membrane 4 has a first
Solution 1 adheres and impregnates. After that, it passes through the interface S3 between the first solution 1 and the third liquid 3, and at this time, a part of the excessive adhesion amount of the first solution 1 is scraped off and passes through the third liquid 3. Since the third solution 3 has a characteristic that both the first solution 1 and the second solution 2 are substantially non-mixed, the interfacial polymerization reaction does not substantially occur in the third solution 3. Furthermore, the third liquid 3 and the second solution 2
It passes through the interface S1 with and is immersed in and passes through the second liquid 2, where an interfacial polymerization reaction occurs and a polymer thin film is formed on the porous hollow fiber membrane. At this time, since a trace amount of the third liquid is present on the surface of the porous hollow fiber membrane, part of the third liquid is taken into the membrane during the reaction between the polyfunctional compound A and the polyfunctional compound B.
The porous hollow fiber membrane 4 has rollers 7 ', 7 in the third liquid 3.
Through the upper part of the third liquid 3 in a substantially vertical direction, and immediately sent to a subsequent process such as a drying process. By using the third liquid in this method, when the porous hollow fiber membrane contacts the second solution, the porous hollow fiber membrane can easily pass almost perpendicularly to each liquid interface without contacting the rollers 7 ′, 7 and the like. it can.

FIG. 6 shows an example in which the adhesion and impregnation of the first solution to the porous hollow fiber membrane is enhanced, and the removal of the excess first solution is enhanced by running the porous hollow fiber membrane in the air. Is shown. The outline of this step will be described below. The porous hollow fiber membrane 4 is immersed in the first solution tank 11 and traveled in the air via the drive rollers 8 ′, 8. Excessive first solution is removed in this air travel. Then, the porous hollow fiber membrane is dipped in the third liquid 3 to drive the drive roller 7 ′,
It is introduced into the second solution 2 through the liquid-liquid interface S1 between the third solution 3 and the second solution 2 via 7 to cause an interfacial polymerization reaction on the outer surface of the porous hollow fiber membrane. The porous hollow fiber membrane 4 having the polymer thin film formed on the outer surface thereof is introduced into the drying cylinder 12 without contact with a driving roller or the like, and thereafter, it is the same as the case of FIG. The amount of the first solution attached to the porous hollow fiber membrane can be adjusted by adjusting the free running distance.

The relationship between the respective solutions and the specific gravities of the solutions is the second solution <
FIG. 7 shows, as a model, the hollow fiber membranes in the case of the third liquid <the first solution, and the portions in contact with the respective solutions and liquids.
The porous hollow fiber membrane 4 is immersed in and passed through the first solution 1, and subsequently passes through the liquid-liquid interface S3 between the first solution 1 and the third liquid 3 via the driving rollers 7 ′, 7 to form the third liquid. Pass through 3. Then, the hollow fiber membrane 4 has a liquid-liquid interface S1 between the third liquid 3 and the second solution 3.
To pass through the second solution 2 and pass therethrough to cause an interfacial polymerization reaction on the outer surface of the porous hollow fiber membrane to form a polymer thin film. At this time, since a trace amount of the third liquid is present on the surface of the porous hollow fiber membrane, part of the third liquid is taken into the membrane during the reaction between the polyfunctional compound A and the polyfunctional compound B. continue,
It is possible to shift to a drying process or the like without contact with a driving roller or the like. In the case of this figure, since the porous hollow fiber membrane does not come into contact with the driving roller even in the third liquid 3, the adhesion state of the first solution on the outer surface of the porous hollow fiber membrane is disturbed by the driving roller or the like. It is possible to cause the interfacial polymerization reaction in the second solution 2 without any action.

[0039]

The present invention will be described below with reference to examples.
The invention is in no way limited by these examples.

Example 1 First, a porous hollow fiber membrane will be described. Spinning consisting of 29% by weight of polysulfone (Udel P-3500 manufactured by Amoco), 14.5% by weight of polyethylene glycol (average molecular weight 600), 0.5% by weight of sodium laurylbenzenesulfonate, and 56% by weight of dimethylacetamide (DMAc). The stock solution was dissolved and stirred for 12 hours at 100 ° C., and after confirming that the spinning stock solution was uniformly dissolved, -50 cmHg, 1
After defoaming at 00 ° C. for 1 hour and then cooling the spinning dope to 50 ° C., a double tube having a spinning dope discharge part outer diameter of 0.66 mm, an inner diameter of 0.5 mm, and a core gas discharge part of 0.2 mm. The stock solution for spinning and the core gas (nitrogen gas) are 0.75 cm ³ / min and 0.30 from the hollow fiber manufacturing nozzle, respectively.
It was discharged at cm ³ / min, and dry-wet spinning was performed at a spinning speed of 15 m / min to obtain a continuous porous hollow fiber membrane. The length of the air gap was 0.5 cm, and a 5 wt% DMAc aqueous solution at 25 ° C. was used as a coagulating liquid. After coagulation, it was washed with water, further subjected to hot water treatment with hot water at 90 ° C. for 1 hour, and immersed and stored in pure water until it was used for forming a composite film. The obtained porous hollow fiber membrane had an outer diameter of 0.3 mm and an inner diameter of 0.2 mm.
In addition, the cross-sectional structure of this porous hollow fiber membrane had a dense layer on the inner and outer surfaces, and the rest had a uniform network throughout.

Twenty porous hollow fiber membranes were bundled to form a loop, one end of which was placed in a holder and fixed with an epoxy resin to open the porous hollow fiber membrane, and the porous hollow fiber membrane bundle effective length of 35 cm.
A mini module having an outer diameter reference membrane area of 132 cm ² was obtained. This porous hollow fiber membrane has a unit membrane area and a pure water permeation amount per unit pressure of 1.0 m ³ / (m ² · day · (kg / cm ² )), and removal of dextran having an average molecular weight of 185,000. The rate was 95%. The performance of the porous hollow fiber membrane was determined as follows.

RO porous water (Toyobo Co., Ltd.) was applied to the above-mentioned porous hollow fiber membrane mini-module at an operating pressure of 5 kg / cm ² and a temperature of 25 ° C.
60 minutes later, the amount of water permeation was measured to obtain the amount of pure water permeation at an operating pressure of 5 kg / cm ² . The removal rate of dextran from the porous hollow fiber membrane was about 5 g with an aqueous solution of dextran at a concentration of 300 g / m ^3.
It was supplied at kg / cm ² and a temperature of 25 ° C., and after 60 minutes, measurement was performed to obtain the dextran removal rate. The dextran removal rate was defined by the following equation. [1- (concentration of dextran in membrane permeate / concentration of dextran in feed stock solution]] × 100 (%)

Next, an example of forming a composite film will be described with reference to the steps of FIG. The traveling speed of the porous hollow fiber membrane 4 was 7 m / min. Piperazine 2% by weight, triethylenediamine 0.5
Wt% and 0.1 wt% of sodium laurylsulfonate were dissolved in pure water to prepare an amine aqueous solution 1, and the continuous porous hollow fiber membrane 4 dipped in the pure water was dipped and passed through this solution for 3 m. . Then, the porous hollow fiber membrane 4 was replaced with 75c.
After running in air, trimesic acid chloride (hereinafter T
(Abbreviated as MC) 1% by weight of TMC dissolved in n-hexane
/ N-Hexane solution 2 was passed vertically through 10 cm to cause an interfacial reaction. Fluorine-based inert liquid 3 as third liquid (Sumitomo 3M Fluorinert FC-
70) and liquid-liquid interface S1 between TMC / n-hexane solution 2
And then passed through the fluorine-based inert liquid 3 for 20 cm. At this time, the fluorine-based inert liquid 3 and TMC / n
No polymerized film was formed at the liquid-liquid interface S1 with the hexane solution 2, and it was speculated that the interfacial polymerization reaction occurred only on the outer surface of the porous hollow fiber membrane 4. These steps were performed at room temperature (about 25 ° C).

Subsequently, the porous hollow fiber membrane 4 is passed through the drying tower 12 at 50 ° C. for 1.5 m, and the washing water 15 in the washing tank 14 is washed.
After being immersed in (pure water at 25 ° C.) for 3 m and passed through, a composite hollow fiber membrane was obtained. 20% of the obtained composite hollow fiber membrane in a wet state
Bundle this into a loop and put one end in a holder and harden it with epoxy resin, open the hollow fiber and let the composite hollow fiber membrane bundle effective length 35
cm (membrane area 132 cm ² ) mini-module was obtained.
The performance of this composite hollow fiber membrane is shown in Table 1. Similarly, in Example 7 of Japanese Patent Publication No. 1-38522, a salt (NaCl) removal rate of 50% is shown as the performance of the composite flat membrane obtained by interfacial polymerization of piperazine and trimesic acid chloride. Although the evaluation pressure is 13.6 atm and the evaluation conditions are different, the salt (NaCl) removal rate of Example 1 of the present invention can be regarded as equal to or higher than this, so that the present invention provides an interface on the outer surface of the porous hollow fiber membrane. It was inferred that a composite hollow fiber membrane in which a polymer thin film was uniformly formed by polymerization was obtained.

The composite hollow fiber membrane performance was determined as follows. The composite hollow fiber membrane mini-module has a temperature of 25 ° C.
At 500 kg / m ³ aqueous solution of NaCl is supplied to the outside of the composite hollow fiber membrane at an operating pressure of 5 kg / cm ² for desalination, and measurement is started 60 minutes later to measure the permeated water per unit membrane area.
The salt concentration was measured. In this case, the recovery rate, that is, the ratio of the amount of permeated water to the amount of supplied water was 5% or less, which was sufficiently small. In the case of CaCl ₂ , it was similarly determined. The salt removal rate was defined by the following equation. [1- (concentration of salt in membrane permeate / concentration of salt in feed stock solution)] × 100 (%)

Further, the obtained composite hollow fiber membrane was vacuum dried at room temperature for 3 days and night, and then 0.3 ml of ethylene glycol was added as a combustion improver to 0.1 g of the sample to prepare an alkali absorbing solution 20.
After burning with a high-pressure oxygen bomb containing ml, F ions in the liquid were quantified by ion chromatography. As a result, 215 ppm of F was detected based on the weight of the dried composite hollow fiber membrane, and it was confirmed that the composite hollow fiber membrane contained a fluorine compound (Fluorinate FC-70).

Example 2 A composite hollow was prepared in the same manner as in Example 1 except that a composite membrane was formed according to the process shown in FIG. 3 and a 1 wt% sodium carbonate aqueous solution was used as the acid scavenger aqueous solution after passing through the third liquid. A thread film was prepared and the performance was evaluated. The performance is shown in Table 1. In this composite hollow fiber membrane, 200 ppm of F was detected.

Example 3 An example of forming a composite membrane was performed according to the process shown in FIG. 4, and the excess amine aqueous solution on the surface of the porous hollow fiber membrane after immersion in the amine aqueous solution was treated with a third solution.
A composite hollow fiber membrane was prepared in the same manner as in Example 1 except that the removal was performed with a liquid, and the performance was evaluated. As the third liquid, a fluorine-based inert liquid (Fluorinert FC-70 manufactured by Sumitomo 3M Limited) was used and passed through it for 20 cm. The performance is shown in Table 1. 331 ppm of F was detected in this composite hollow fiber membrane.

Example 4 Example 4 was carried out in the same manner as in Example 1 except that an example of forming a composite membrane was performed according to the process shown in FIG. 2 and the excess amine aqueous solution on the surface of the porous hollow fiber membrane after immersion of the amine aqueous solution was removed by a drying cylinder. A composite hollow fiber membrane was produced in this way, and the performance was evaluated. As a drying condition, a drying cylinder having a temperature of 40 ° C. was passed through for 2 m. The performance is shown in Table 1. In this composite hollow fiber membrane, 17
0 ppm of F was detected.

Example 5 The concentrations of polysulfone, polyethylene glycol and DMAc in the spinning dope were 29% by weight, 23.2% by weight and 47.3% by weight respectively, and the spinning dope discharge flow rate, core gas flow rate, spinning speed, Air gap length, coagulation liquid D
MAc concentrations of 0.54 cm ³ / min and 0.86, respectively
A continuous porous hollow fiber membrane was obtained by the same production method as in Example 1 except that the content was cm ³ / min, 30 m / min, 1 cm, and 30% by weight. When this porous hollow fiber membrane was evaluated in the same manner as in Example 1, the pure water permeation rate was 0.77 m ³ / (m ² · day · (kg / c
The removal rate of m ² )) and dextran was 88.8%.

An example of forming a composite film was performed according to the process shown in FIG. The running speed of the porous hollow fiber membrane 4 is 1 m / min. In the same manner as in Example 1, the porous hollow fiber membrane 4 was impregnated with amine water. Subsequently, this porous hollow fiber membrane 4 was run in the air for 40 cm, and then passed through a fluorine-based inert liquid 3 (Fluorinert FC-70 manufactured by Sumitomo 3M Co., Ltd.) as a third liquid for 20 cm, and 1% by weight of TMC was n. After the liquid-liquid interface S1 between the TMC / n-hexane solution 2 dissolved in -hexane and the fluorine-based inert liquid 3 is penetrated, the TMC /
An interface reaction was caused by passing through the n-hexane solution 2 for 10 cm. At this time, the fluorine-based inert liquid 3 and TMC / n
No polymerized film was formed at the liquid-liquid interface S1 with the hexane solution 2, and it was speculated that the interfacial polymerization reaction occurred only on the outer surface of the porous hollow fiber membrane 4. These steps were performed at room temperature (about 20 ° C). Subsequently, the porous hollow fiber membrane 4 was passed through the drying tower 12 at 50 ° C. for 3 m, and the same treatment and performance evaluation as in Example 1 were performed, and the performance obtained is shown in Table 1. In this composite hollow fiber membrane, 375 ppm
F was detected.

Comparative Example 1 A porous hollow fiber membrane was prepared according to Example 1, and a composite hollow fiber membrane was prepared by the process shown in FIG. 8 in which the third liquid was not used. The part different from the first embodiment will be described. The porous hollow fiber membrane 4 was immersed in the amine aqueous solution 1 for 3 m and allowed to pass therethrough, and then the porous hollow fiber membrane 4 was run in the air for 75 cm.
/ N-hexane solution 2 was passed through 10 cm to cause an interfacial polymerization reaction, and then passed through a drying cylinder 12 at 50 ° C., and thereafter, treated in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Was carried out. The performance is shown in Table 1. Compared to Example 1, the separation performance, that is, the salt removal rate was low. In addition, F was not detected in this composite hollow fiber membrane. In this method, in the TMC / n-hexane solution 2, an interfacial polymerized film is formed on the outer surface of the porous hollow fiber membrane, and the driving rollers 7 ′, 7 and the outer surface 4 of the porous hollow fiber are in contact with each other. Therefore, it is speculated that the formed polymer thin film is damaged such as peeling off.

Comparative Example 2 A porous hollow membrane was produced according to Example 5, and a composite hollow fiber membrane was produced by the flow step shown in FIG. 8 without using the third liquid. The part different from the fifth embodiment will be described. The porous hollow fiber membrane 4 was immersed in the amine aqueous solution 1 for 3 m and allowed to pass therethrough, and then the porous hollow fiber membrane 4 was run in the air for 40 cm, and then the TMC was used.
After passing through the / n-hexane solution 2 for 10 cm to cause an interfacial polymerization reaction, it was passed through a drying cylinder 12 at 50 ° C., and thereafter, the same treatment as in Example 5 was carried out to evaluate the performance. The performance is shown in Table 1. As a result, the separation performance, that is, the salt removal rate was lower than that of Example 5. In addition, F was not detected in this composite hollow fiber membrane. In this method, in the TMC / n-hexane solution 2, an interfacial polymerized film is formed on the outer surface of the porous hollow fiber membrane, and the driving rollers 7 ′, 7 and the outer surface 4 of the porous hollow fiber are in contact with each other. Therefore, it is speculated that the formed polymer thin film is damaged such as peeling off.

Comparative Example 3 A porous hollow fiber membrane was produced according to Example 5, and a composite hollow fiber membrane was produced by the process shown in FIG. 9 in which the third liquid was not used. The part different from the fifth embodiment will be described. The porous hollow fiber membrane 4 was immersed in the amine aqueous solution 1 for 3 m and allowed to pass therethrough, and then the porous hollow fiber membrane 4 was run in the air for 40 cm, and then immersed again in the amine aqueous solution 1 for 20 cm to pass therethrough to obtain the amine aqueous solution 1. The liquid-liquid interface S4 of the TMC / n-hexane solution 2 was penetrated. At the liquid-liquid interface S4, a polymer thin film presumed to be due to an interfacial polymerization reaction was formed. Then TM
After passing through C / n-hexane solution 2 for 10 cm, 50
After passing through the drying cylinder 12 at ℃, after that, the same treatment as in Example 5 was carried out, and the performance evaluation was carried out. The performance is shown in Table 1. The separation performance, that is, the salt removal rate, was lower than that in Example 5. In addition, F was not detected in this composite hollow fiber membrane. In this method, since the third liquid is not used, a polymer thin film is formed by interfacial polymerization at the liquid / liquid interface S4 of the amine aqueous solution and the TMC / n-hexane solution, and the thickness of the polymer thin film changes with the elapse of the composite film forming operation time. Increase and inhibit the formation of a polymer thin film on the outer surface of the porous hollow fiber membrane,
It is assumed that the separation performance, that is, the salt removal rate is low.

[0055]

[Table 1]

[0056]

EFFECT OF THE INVENTION The composite hollow fiber membrane of the present invention comprises a porous hollow fiber membrane on the outer surface of which a polyamide polymer thin film is continuously and stably formed by an interfacial polymerization method. It is an excellent composite hollow fiber membrane. Therefore, the composite hollow fiber membrane of the present invention is used as a reverse osmosis membrane for desalination by desalting brine, seawater, etc., for producing ultrapure water used for semiconductor production, and for a nanofiltration membrane, for producing small pure water. It can be used in various fields such as equipment, water purifier use, advanced water purifier use, valuables recovery use, wastewater treatment use, etc.

[Brief description of drawings]

FIG. 1 shows the relationship between the specific gravity and the second solution in Manufacturing Method I.
The model figure of an example of the contact method of each liquid to a porous hollow fiber membrane in the case of a 3rd liquid is shown.

FIG. 2 is a schematic flow chart showing an example of a composite film formation step in the case where the second solution and the third solution form a liquid-liquid interface in the production method I.

FIG. 3 is a model diagram showing an example of a method of contacting each liquid with the porous hollow fiber membrane when the aqueous solution of the acid scavenger is immersed in the production method I after passing through the third liquid.

FIG. 4 is a schematic flow chart showing an example of a composite membrane-forming step in the case where the excess first solution on the surface of the porous hollow fiber membrane after immersion in the first solution is removed by the third solution in the production method I.

FIG. 5: In Manufacturing Method II, the magnitude relationship between specific gravities is the second solution <
The model figure of an example of the contact method of each liquid to a porous hollow fiber membrane in case of 1st solution <3rd liquid is shown.

FIG. 6 shows a schematic flow of an example of a composite film forming step in the case where the second solution and the third solution form a liquid-liquid interface in the production method II.

FIG. 7: In Manufacturing Method II, the magnitude relationship between specific gravities is that of the second solution <
The model figure of an example of the contact method of each liquid to the porous hollow fiber membrane in case of 3rd liquid <1st solution is shown.

FIG. 8 shows a schematic flow chart of a composite film forming process in Comparative Examples 1 and 2.

FIG. 9 shows a schematic flow chart of a composite film forming step in Comparative Example 3.

[Explanation of symbols]

 1: First solution (amine aqueous solution) 2: Second solution (TMC / n-hexane solution) 3: Third solution (fluorine-based inert liquid) 4: Porous hollow fiber membrane 5: Solution tank 6: Partition 7, 7 ': Drive roller 8, 8'9, 9': Drive roller 10: First solution tank 11: Porous hollow fiber membrane supply tank 12: Drying cylinder 13, 13 ': Drive roller 14: Wash tank 15: Wash water 16, 16 ': Driving roller 17, 17': Driving roller 18: Composite hollow fiber membrane receiving tank 19, 19 ': Driving roller 20: Acid scavenger aqueous solution 21: Third liquid tank 22: Driving roller S1: Interface between second solution and third solution S2: Interface between aqueous solution of acid scavenger and third solution S3: Interface between first solution and third solution S4: Interface between first solution and second solution Explanation in comparative example

Claims (12)

[Claims] 1. A composite hollow fiber membrane comprising a porous hollow fiber membrane and a polyamide polymer thin film coating the outer surface of the porous hollow fiber membrane, wherein the composite hollow fiber membrane contains a fluorine compound. A composite hollow fiber membrane characterized by: 2. The composite hollow fiber membrane according to claim 1, wherein the fluorine compound is a perfluoro compound and / or a compound having a perfluoroalkyl group. 3. The composite hollow fiber membrane according to claim 1 or 2, wherein the content of the fluorine compound is 1 to 1000 ppm as the amount of fluorine per weight of the composite hollow fiber membrane. Thread film. 4. The composite hollow fiber membrane according to claim 1, wherein the polyamide-based polymer is a crosslinked polyamide-based polymer. 5. The composite hollow fiber membrane according to claim 1, wherein the material of the porous hollow fiber membrane is a polysulfone polymer. 6. The composite hollow fiber membrane according to claim 1, which has an operating pressure of 5 kg / cm ² , a temperature of 25 ° C., and a pH.
The water permeability in 6 is 0.5 m ³ / m ² · day or more,
A composite hollow fiber membrane characterized by having a salt removal rate of 0.05% by weight of saline solution of 50% or more. 7. The method for producing a composite hollow fiber membrane according to claim 1, wherein the polyfunctional compound A having at least two reactive amino groups and comprising at least one type is used. A first solution containing the first hollow fiber membrane and a second solution containing a polyfunctional compound B composed of at least one polyfunctional acid halide and substantially immiscible with the first solution, and the porous hollow fiber membranes in order. The porous hollow fiber membranes are contacted with each other to form a thin film by interfacially polymerizing the polyfunctional compounds A and B on the outer surface of the porous hollow fiber membranes to produce a continuous composite hollow fiber membrane. And, after contacting the second solution with the first solution, contacting at least one location with a third solution that is substantially immiscible with the second solution and contains a fluorine compound. A method for producing a composite hollow fiber membrane. 8. The method for producing a composite hollow fiber membrane according to claim 1, wherein the polyfunctional compound A having at least two reactive amino groups and comprising at least one type is used. A first solution containing the first hollow fiber membrane and a second solution containing a polyfunctional compound B composed of at least one polyfunctional acid halide and substantially immiscible with the first solution, and the porous hollow fiber membranes in order. The porous hollow fiber membranes are contacted with each other to form a thin film by interfacially polymerizing the polyfunctional compounds A and B on the outer surface of the porous hollow fiber membranes to produce a continuous composite hollow fiber membrane. , At least a third liquid containing a fluorine compound that is substantially immiscible with both the first and second solutions during contacting the first solution with the second solution. A method for producing a composite hollow fiber membrane, which comprises contacting at one location. 9. The method for producing a composite hollow fiber membrane according to claim 7 or 8, wherein the second solution and the third solution form a liquid-liquid interface. 10. The manufacturing method according to claim 8,
A method for producing a composite hollow fiber membrane, wherein the first solution and the third solution form a liquid-liquid interface. 11. The manufacturing method according to claim 7, wherein
A method for producing a composite hollow fiber membrane, wherein the third liquid is substantially immiscible with the first solution and the second solution. 12. The method according to claim 7 or 8, further comprising means for removing an excess of the first solution on the surface of the porous hollow fiber membrane after contacting the first solution. A method for producing a composite hollow fiber membrane characterized.