JPH01159008A - Manufacture of hollow polysulfone fiber membrane - Google Patents

Abstract

PURPOSE:To produce a hollow fiber membrane excellent in water permeability, without impairing the fractionated molecular weight and physical strength, by using polyether as an additive to a spinning solution of polysulfone with 2-pyrrolidone as a solvent. CONSTITUTION:A spinning solution for making fibers is prepared, which consists of polysulfone, 2-pyrrolidone and N-methyl-2-pyrrolidone as a solvent and triethylene glycol as an additive. Hollow fibers are produced by spinning this solution into water by means of a tube-in-orifice type nozzle using a solidification liquid such as an aqueous solution of polyethylene glycol. The hollow fibers thus obtained are washed with a warm water for removal of the solvent to obtain the hollow fiber membrane of polysulfone.

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 particularly to a method for producing a hollow fiber separation membrane made of a polysulfone polymer with excellent water permeability. Regarding the manufacturing method.

[Prior art]

Polysulfone, known as engineering plastics, has excellent mechanical properties, heat resistance, and chemical resistance, so it is used in the precision parts field, including household goods and medical devices. is also widely used.

Since such polysulfone can be easily spun into hollow fibers, it can be used as a hollow fiber separation membrane for gas and liquid separation. In particular, it is extremely useful 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 borisulfone resin with dimethylacetamide (DMAc), dimethylformamide (DMF), N
-Methyl-2-pyrrolidone (NMP), dioxane (
DOX), tetramethylurea (TMU), or other organic solvent to prepare a stock solution for spinning yarn, and the stock solution is discharged together with the internal coagulation liquid from a double annular nozzle into a water-soluble bath to form fine particles. A hollow fiber-like separation membrane with a porous structure is obtained.

[Problem that the invention seeks to solve]

However, polysulfone hollow fiber membranes obtained by the above manufacturing method generally have a low water permeation rate, so BS
There was a problem that recovery or separation using IIQ required a long time and productivity was low.

Therefore, the present invention is characterized by producing a hollow fiber membrane having excellent water permeability without impairing the characteristics 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 8001/m".
hr −kg/cm” or more, preferably 12001/cm
The object of the present invention is to obtain a polysulfone hollow fiber separation membrane having a water permeability of m"·hr-kg/cm" or more.

:Means for Solving the Problems] As a result of intensive study and research in order to solve the above problems, the present inventors added polyether as an additive to a polysulfone-based spinning dope using 2-pyrrolidone as a solvent. By incorporating these compounds, they succeeded in obtaining a polysulfone hollow fiber membrane having an extremely high water permeability that cannot be obtained with conventional polysulfone hollow fiber membranes, thereby completing the present invention.

That is, the present invention provides a method for producing a polysulfone hollow fiber separation membrane from a polysulfone-based spinning stock solution using 2-pyrrolidone as a solvent, which is characterized in that polyether is used as an additive in the spinning stock solution. The present invention provides a method for manufacturing.

Examples of the polysulfone polymer used in the present invention include polysulfone represented by the following structural formula or a derivative thereof.

(However, n is an integer.) In the present invention, the concentration of the polysulfone polymer in the spinning dope is preferably 5 to 30% by weight, particularly 10 to 30% by weight.
Weight percent is preferred. The concentration of polysulfone polymer is 30
If it exceeds % by weight, the viscosity of the solution increases, making it difficult to handle, and the water permeation rate of the obtained hollow fiber membrane decreases, which is not preferable. On the other hand, when the concentration is less than 5% by weight, the mechanical strength of the resulting hollow fiber membrane decreases, which is not preferable.

In the present invention, 2-pyrrolidone used as a solvent is added to the spinning dope containing the polysulfone polymer.
It is preferably contained in an amount of 5% by weight or more. 2 in the spinning dope
- If the content of pyrrolidone is less than 15%, the polysulfone hollow fiber membrane with excellent water permeability, which is the object of the present invention, cannot be obtained.

Other solvents that can be used in combination with 2-pyrrolidone include, but are not particularly limited to, N-methyl-2τpyrrolidone, dioxane, tetramethylurea, dimethylacetamide, dimethylformamide, and the like. Moreover, you may use these mixed solvents.

The polyether that is an essential component of the present invention includes polyethylene glycol (PEG) having various molecular weights.
) IJf can generally be used, but is not particularly limited thereto. Further, when polyethylene glycol having an average molecular weight of 600 or more is added, a hollow fiber membrane having extremely high water permeability can be obtained.

The amount of polyether added is not particularly limited as long as the prepared spinning stock solution is uniform, but it is particularly preferably contained in the spinning stock solution in an amount of 5 to 30% by weight. If the fffi content of polyether in the spinning dope is less than 5% by weight, it will be difficult to obtain a polysulfone hollow fiber membrane with excellent water permeability, which is the objective of the present invention, and if it exceeds 30% by weight, the viscosity of the solution will increase. , which is not preferable because it becomes difficult to handle.

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 coagulation liquid is
Examples include water, alcohols such as methanol, ethanol, propatool, and butanol, or aqueous solutions of these alcohols, polyethers typified by polyethylene glycol, and aqueous solutions thereof. Furthermore, it is also possible to use various organic solvents in combination with the above-mentioned coagulating liquid. The internal coagulating liquid can be freely selected depending on whether the skin layer that exhibits the iJ 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 P4
700) 20 parts by weight, 2-pyrrolidone 20 as a solvent
A spinning stock solution consisting of 40 parts by weight of N-methyl-2-pyrrolidone and 20 parts by weight of triethylene glycol (TrEG) as an additive was discharged into water from a tube-in-orifice type nozzle to spin hollow fibers. The internal coagulation liquid is polyethylene glycol (P) with an average molecular weight of 200.
Using an 80% aqueous solution of EG200), the air travel distance was 10.
cm, external coagulation liquid is 20m/m using 60°C hot water
Spun in.

Next, the obtained hollow fibers were heated for 6 hours until the solvent was completely removed.
Washed with 0°C warm water.

The pure water permeability rate of the hollow fiber membrane thus obtained was 1100
(17 m"·hr-kg/cm").

Examples 2 to 8 Using the same polysulfone as used in Example 1, a spinning dope having the composition shown in Table 1 was prepared, and using this spinning dope, hollow system spinning was carried out under exactly the same conditions as in Example 1. The pure water permeation rate of the obtained hollow fiber membrane was extremely good as shown in Table 1.

Comparative Example 1 Using the same polysulfone as used in Example 1, a spinning stock solution having the composition shown in Table 1 was prepared without adding any additives, and the spinning stock solution was used under exactly the same conditions as in Example 1. Hollow fiber was spun. The pure water permeability rate of the hollow fiber membrane thus obtained was 200 e 7 m"・hr-kg/cm"
It was extremely low.

Table 1 Note) PSF: Polysulfone 2PN: 2-pyrrolidone NMP: N-methyl-2-pyrrolidone TrEG:)
Liethylene glycol PEG200: Polyethylene glycol with an average molecular weight of 200 PEG300: Polyethylene glycol with an average molecular weight of 1300 Examples 9 to 13 Using the same polysulfone as used in Example 1, a spinning dope having the composition shown in Table 2 was prepared, and this spinning solution was prepared. Hollow fibers were spun under exactly the same conditions as in Example 1, except that the stock solution was used and a 75% aqueous solution of polyethylene glycol (PEG200) with an average molecular weight of 200 was used as the internal coagulation liquid.

The pure water permeation rate of the obtained hollow fiber membranes is shown in Table 2.

As is clear from Table 2, in particular, additives with an average molecular weight of 6
00 polyethylene glycol (PEG600), average molecular weight 11000 polyethylene glycol (PEG10)
When using polyethylene glycol (PEG2000) with an average molecular weight of 12,000 (0O) and an average molecular weight of 12,000, hollow fibers having an extremely high water permeation rate were obtained.

Table 2 Comparative Examples 2 to 5 Using the same polysulfone as used in Example 1 and replacing the additives with those shown in Table 3, a spinning dope having the composition shown in Table 3 was prepared. When hollow fibers were spun under exactly the same conditions as the above, as shown in Table 3, in each case 800 j! A hollow membrane having a pure water permeation rate of 7 m"·hr -kg/cm" or higher was not obtained.

Table 3 Note) TGM Nitriethylene glycol dimethyl ether ECS: Ethyl cellosolve DATA Nidiacetone alcohol DMSO Nidimethyl sulfoxide [Effects of the invention] As explained above, the polysulfone hollow fiber membrane obtained by the production method of the present invention is It has extremely superior water permeability compared to hollow fiber membranes with similar fractionation performance.

Applicant's agent Kaoru Furutani

Claims (3)

[Claims] (1) In a method for producing a polysulfone hollow fiber separation membrane from a polysulfone spinning dope using 2-pyrrolidone as a solvent, the production of a polysulfone hollow fiber membrane is characterized in that polyether is used as an additive in the spinning dope. Law. (2) The method for producing a polysulfone hollow fiber membrane according to claim 1, wherein the content of 2-pyrrolidone in the spinning dope is 15% by weight or more. (3) The method for producing a polysulfone hollow fiber membrane according to claim 1, wherein the polyether is polyethylene glycol having an average molecular weight of 600 or more.