JPH01176407A - Production of hollow yarn membrane made of polysulfone - Google Patents

Abstract

PURPOSE:To improve the operability of spinning and to contrive enhancement of water permeability while maintaining fractionation performance by utilizing triethylene glycol dimethyl ether as the solvent of spinning raw liquid consisting of a polysulfone-base polymer, spinning and discharging the mixture into an aq. soln. CONSTITUTION:Triethylene glycol dimethyl ether (preferably 10wt.% or more and it may be mixed with the other solvent such as 2-pyrrolidone and used) is used as the solvent of spinning raw liquid consisting of a polysulfone-base polymer and the mixture is spun and discharged in an aq. soln. to produce a hollow yarn membrane. The membrane obtained thereby has fractionation performance of the same degree as the conventional membrane and is excellent in water permeability. Furthermore since triethylene glycol dimethyl ether has very excellent solubility for the polysulfone-base polymer, the viscosity of the spinning raw liquid is made low and both operability and productivity at a time for producing the hollow yarn membrane are made very excellent.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing a hollow fiber separation membrane made of a polysulfone polymer, and more specifically, to a method for producing a hollow fiber separation membrane made of a polysulfone-based polymer, and more specifically, to a method for producing a hollow fiber separation membrane made of a polysulfone polymer, and more specifically to a method for producing a permselective hollow fiber separation membrane with excellent fluid separation properties. The present invention relates to a method for manufacturing with high productivity a hollow fiber separation membrane made of a polysulfone polymer that has excellent strength and ease of handling.

[Conventional technology]

Polysulfone polymers, known as engineering plastics, have excellent mechanical properties, heat resistance, chemical resistance, and microbial resistance, so they are used in electronic parts and household goods, and as separation membranes for colloidal substances and other materials. Used in a variety of fields, including protein separation and purification, electrodeposition coating bath management, ultrapure water production for the electronics industry, atomic crab industry, seawater desalination, and even medical equipment fields such as blood processing using artificial kidneys. has also been widely put into practical use.

Since such polysulfone can be easily spun into hollow fibers, it can be used as a hollow fiber separation membrane for gas-liquid separation.

It is an extremely useful material especially as an ultrafiltration membrane under high temperature, strongly acidic or strongly alkaline conditions.

Methods for manufacturing such polysulfone hollow fiber separation membranes include, for example, JP-A-54-145379 and JP-A-54-145379.
No. 152704, No. 58-8504, No. 58-132
No. 112, No. 58-156018, No. 59-5804
No. 0, No. 59-58042, No. 59-62311,
No. 59-189903, No. 60-172312, No. 60-222112, No. 61-11110, No. 61
-28409, 61-42307, 61-43
The methods described in each publication No. 07 are known. These methods combine polysulfone resin with dimethylacetamide (DMAc), dimethylformamide (DMF), N
-Methyl-2-pyrrolid 7 (NMP), dioxane (
A stock solution for spinning is prepared by dissolving it in an organic solvent such as DOx), tetromethylurea (TMU), etc., and the stock solution is discharged together with an internal coagulation liquid from a double annular nozzle into a water-soluble bath to form fine pores. This method provides a hollow fiber-like separation membrane with a high quality structure.

[Problem that the invention seeks to solve]

However, since the polysulfone hollow fiber membranes obtained by the above manufacturing method generally have low water permeability, they require a long time for separation, recovery, and operation, resulting in a problem of low productivity.

Therefore, the present invention is characterized by producing a hollow fiber membrane having excellent water permeability without impairing the properties required for an ultrafiltration membrane, that is, molecular weight cutoff and mechanical strength. , when performing ultrafiltration with a molecular weight cut-off of approximately 100,000, the water permeation rate is 800117 m''.
hr-kg/cm” or more, preferably 12001!7
The object of the present invention is to obtain a polysulfone hollow fiber separation membrane having a water permeability of m''·hr-kg/cIIt or more.

Means for Solving the Problems] In view of the above circumstances, the inventors of the present invention have conducted extensive studies and research to solve the above problems, and as a result, have prepared a polysulfone resin spinning dope to be discharged from an annular nozzle. When doing
By containing triethylene glycol dimethyl ether (1,2-bis(2-methoxyethoxy)ethane) as a solvent in the polysulfone spinning stock solution, polysulfone hollow fiber membranes have an extremely high water permeability that cannot be obtained with conventional polysulfone hollow fiber membranes. Succeeded in obtaining thread membrane,
The present invention has now been completed.

That is, the present invention provides a method for manufacturing a hollow fiber separation membrane by discharging a spinning stock solution containing a polysulfone polymer into an aqueous solution from a tube-in-orifice type nozzle and then removing the solvent. The present invention provides a method for producing a polysulfone hollow fiber membrane characterized by using triethylene glycol dimethyl ether.

Typical polysulfone polymers used in the present invention include those having repeating units represented by the following general formula (1) or (n).

(Xs)-, (X&)Q However, in formulas (I) and (II), X1 to X6 are non-dissociative substitutions such as alkyl groups such as methyl and ethyl groups, and halogens such as chlorine and bromine. group, or -COOH,
Indicates a dissociable substituent such as -5OsH, L ll+ n
+O+ p and q represent integers from O to 4; -Tactically, 2. Polysulfone in which all of So + L O19 and q are 0 is easily available and is preferably used in the present invention. However, the polysulfone polymer used in the present invention is not limited to the above.

The concentration of the polysulfone polymer in the spinning dope in the present invention is preferably 5 to 30% by weight, particularly 10 to 30% by weight.
is preferred. Concentration of polysulfone polymer is 30% by weight
Exceeding this is not preferred because the viscosity of the solution increases, making it difficult to handle, and the water permeation rate of the resulting hollow fiber membrane decreases regardless of the solvent system used. on the other hand,
When the concentration of polysulfone polymer is less than 5% by weight,
This is not preferred because the mechanical strength of the hollow fiber membrane obtained is reduced.

Triethylene glycol dimethyl ether used as a solvent in the present invention is an essential component of the present invention, and is preferably contained in the spinning dope containing the polysulfone polymer in an amount of 10% by weight or more, preferably 20% by weight.
It is particularly preferable that the above is included. If the content of triethylene glycol dimethyl ether in the spinning dope is less than 10% by weight, a polysulfone hollow fiber membrane with excellent water permeability, which is one of the objects of the present invention, can be obtained, but the viscosity of the spinning dope is high ( In other words, since triethylene glycol dimethyl ether has very good compatibility with polysulfone polymers, the polysulfone spinning stock solution using triethylene glycol dimethyl ether as a solvent has a low viscosity, making it difficult to operate during hollow fiber production. It also has the effect of greatly improving performance and productivity.

In the present invention, other solvents that can be used in combination with triethylene glycol dimethyl ether include 2-
Examples include, but are not limited to, pyrrolidone, N-methyl-2-pyrrolidone, dioxane, tetramethylurea, dimethylacetamide, and dimethylformamide. Moreover, you may use these mixed solvents.

Among the above-mentioned solvents that can be used in combination with triethylene glycol dimethyl ether, 2-pyrrolidone is particularly preferred, and 2-pyrrolidone may be included together with triethylene glycol dimethyl ether in the spinning dope containing the polysulfone polymer. As a result, a polysulfone hollow fiber membrane having particularly excellent water permeability, which is the object of the present invention, can be obtained. Further, the spinning dope in this case has a low viscosity and has good operability, handleability, and productivity during hollow fiber production. At this time, the content of 2-pyrrolidone in the spinning dope is preferably 10 to 60% by weight, particularly preferably 20 to 50% by weight.゛The non-solvent added as an additive to the spinning dope in the present invention is particularly polyethylene glycol (average molecular weight 2
00.300.400.600.1000°2000, etc.), and the content of polyethylene glycol in the spinning dope is not particularly limited as long as the resulting mixed solution can maintain a homogeneous solution state, but it is at least 0.5% by weight. %
The above amount may be added and determined by considering the concentration of the polymer, the type of solvent, hollow fiber formability, and membrane performance. Polyethylene glycol in the spinning dope is effective in increasing the water permeability of the membrane during the coagulation process during hollow fiber production.

In the present invention, non-solvents added as additives to the spinning stock solution in addition to the polyethylene glycol mentioned above include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, aliphatic polyhydric alcohols such as glycerin, methanol, ethanol, and isopropyl alcohol. Lower aliphatic alcohols such as dioxane, cyclic ethers such as tetrahydrofuran, lower aliphatic ketones such as acetone and methyl ethyl ketone, dimethyl sulfoxide and the like are preferably used, but are not particularly limited to these.

According to the method of the present invention, the spinning stock solution prepared as described above is discharged into an aqueous solution using a tube-in-orifice type nozzle. At this time, the internal coagulating liquid is preferably water, alcohols such as methanol, ethanol, propatool, butanol, or aqueous solutions of these alcohols. The internal coagulating liquid can be freely selected depending on whether the skin layer that performs the separation function of the membrane is formed on the inner surface or the outer surface of the hollow fiber.

Further, the temperature of the coagulating liquid is usually 30 to 85°C, preferably 40 to 70°C, when water is used as the coagulating liquid.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Polysulfone (manufactured by UCC, needle polysulfone P-
1700) was dissolved in a mixed solvent of triethylene glycol dimethyl ether and 2-pyrrolidone (weight ratio 1:1), and polyethylene glycol (PEG100O; manufactured by Sanyo Chemical Co., Ltd.) with an average molecular weight of 1000 was further added as a non-solvent.
A hollow fiber spinning stock solution containing 20% by weight of polysulfone was prepared by adding 15% by weight of polysulfone.

This spinning stock solution was filtered and defoamed to remove dust and gas contained in the stock solution, and then discharged into water from a chain-in orifice type double-ring nozzle to spin hollow fibers. Spinning was carried out at 20 m/sin using an 80% polyethylene glycol aqueous solution as the internal coagulating liquid and using hot water at 70° C. as the external coagulating liquid with an aerial travel distance of 10 cm. Next, the obtained hollow fibers were heated at 60°C until the solvent was completely removed.
Washed with warm water.

When purified water (pure water) was permeated through the hollow fiber membrane thus obtained at a water pressure of 1 kg/cm'' and the permeation rate was measured, it was found to be extremely high at 120012/la'' hr-kg/cm. In addition, the transmittance of a protein (conalbumin) having a molecular weight of 87,000 was 41%.The viscosity of the spinning stock solution was also as low as 13,880 cp.

Examples 2 to 9 Using the same polysulfone as used in Example 1, a spinning dope having the composition shown in Table 1 was prepared, and this spinning dope was used to spin hollow fibers under the same conditions as in Example 1. I did it. The permeation rate of the obtained hollow fiber membrane was measured in the same manner as in Example 1.

The results obtained are shown in Table 1. Moreover, the fractionation performance and the viscosity of the spinning dope were almost the same as in Example 1.
Table note) PSF; Polysulfone TGM; ) Liethylene glycol dimethyl ether 2PN; 2-pyrrolidone PEG100O; Polyethylene glycol with an average molecular weight of 1000 PEG200: Polyethylene glycol with an average molecular weight of 200 PEG600; Polyethylene glycol with an average molecular weight of 600 Comparative example 1 Polysulfone (manufactured by UCC, Needle polysulfone P-
1700) t-) Polyethylene glycol with an average molecular weight of 200 (pH! G200;
(manufactured by Sanyo Kasei) to give a concentration of 20% by weight, to prepare a hollow fiber spinning stock solution containing 20% by weight of polysulfone.

The obtained hollow fiber spinning stock solution caused two-phase separation and spinning was impossible.

Comparative Example 2 Polysulfone was dissolved in a mixed solvent of 2-pyrrolidone:dimethyl sulfoxide (weight ratio 2:1) without using triethylene glycol dimethyl ether as a solvent, and 20 weight of polyethylene glycol having an average molecular weight of 200 was added as a non-solvent. %, and a hollow fiber spinning stock solution containing 20% by weight of polysulfone was prepared.

Although the obtained hollow fiber spinning stock solution was dissolved, the viscosity of the spinning stock solution was so high that spinning was impossible.

Comparative Example 3.4 Spinning was carried out in the same manner as in Example 1 except that triethylene glycol dimethyl ether was not used as the polysulfone solvent, but the solvents and additives shown in Table 2 were used.

As shown in Table 2, the obtained hollow fiber membranes all had low water permeability.

Table 2 Note) DMSO; dimethyl sulfoxide DMAc; dimethyl acetamide TMU; tetramethyl urea NMP; N-methyl-2-pyrrolidone [Effects of the invention] As explained above, according to the production method of the present invention, hollow fibers It has excellent operability during spinning, and the performance of the obtained hollow fiber membrane is extremely superior in water permeability compared to conventional hollow fiber membranes having the same degree of fractionation performance.

Applicant's agent Kaoru Furutani −2

Claims (2)

[Claims] (1) Triethylene is used as a solvent for the polysulfone spinning dope in a method in which a spinning dope containing a polysulfone polymer is discharged into an aqueous solution through a tube-in-orifice nozzle, and then the solvent is removed to produce a hollow fiber separation membrane. A method for producing a polysulfone hollow fiber membrane characterized by using glycol dimethyl ether. (2) Triethylene glycol dimethyl ether 2-
A method for producing a polysulfone hollow fiber membrane according to claim 1, which is used together with pyrrolidone as a solvent for a polysulfone spinning dope.