JPS5834009A - Preparation of aromatic polysulfone hollow semi-permeable membrane - Google Patents

Abstract

PURPOSE:To prepare a hollow semi-permeable membrane having high water permeability and mechanical properties, by a method wherein a solution of an aromatic polysulfone in which glycols are also present is extruded in a hollow shape and the resulting hollow extrudate is coagulated. CONSTITUTION:An aromatic polysulfone is dissolved in a polar org. solvent such as N-methylpyrrolidone, dimethylformamide or dimethylacetamide and glycols such as ethylene glycol, propylene glycol, glycerol or trimethylolpropane are added to the resulting solution in an amount of 0.5% or more. The obtained mixed solution is extruded through an annular die and the extrudate is coagulated in a coagulating bath such as water from the inner and the outer sides thereof. Because of the presence of glycol, fine pores are formed to increase the water permiability 2-10 times and the precipitation of the polymer is facilitated to give a layer having no voids on the surface of a membrane. Thus a hollow membrane excellent in compaction resistance and mechanical strength is obtained.

Description

Detailed Description of the Invention Aromatic polysulfone having a repeating unit represented by the following general formula (1) (provided that X, X'S!', !" in the formula include methyl, ethyl, etc.) Non-dissociative substituents such as alkyl, chlor, pro-5, etc. or dissociative substituents such as 11-COOH, gO, H, etc. The aromatic polysulfone hollow semipermeable membrane obtained by the manufacturing method of the present invention basically has special properties. It has a structure similar to that disclosed in Kaisho J Gu No. 141332.The present inventors have now achieved a solution equivalent to or similar to the prior invention by hollow extrusion solidifying a solution of aromatic polysulfone in which glycols coexist. It has been found that an aromatic polysulfone hollow membrane having even better performance can be obtained.

The method of the present invention is noteworthy in that it enables the production of a polysulfone hollow semipermeable membrane having both high water permeability and mechanical properties from a highly concentrated polymer solution.

The present invention involves discharging a polar organic solvent solution of aromatic polysulfone containing glyfurs into a hollow shape from an annular nozzle, and then contacting it with a liquid that is miscible with the axillary mixed solvent but does not disturb the aromatic polysulfone. The present invention relates to a method for manufacturing a hollow semipermeable membrane, characterized in that a l# medium is used.

A solution of aromatic polysulfone containing glycol Ii in a polar organic solvent can be prepared by dissolving the aromatic polysulfone polymer in a polar organic solvent that well dissolves the polymer and adding glycols.

The hollow semipermeable membrane of the present invention can be obtained by extruding this mixed solution typically through an annular nozzle for manufacturing hollow fibers and coagulating it from the inside and outside. When forming a hollow semipermeable membrane, aromatic polysulfone dissolved in a polar organic solvent enters the coagulation solution from both the inner and outer surfaces, causing precipitate around the glycol core, and the areas where the glycols touch each other become pores. is estimated to form. The presence of glycol is significant as a nucleus for the formation of pores, and greatly contributes to improving water permeability. Compared to the case where glycol is not used, water permeability increases approximately 2 to 70 times, and the polymer chain It is estimated that this affects the spread and has some influence on the membrane structure. The presence of glycol makes it difficult for aromatic polysulfone to form a precipitate in the polar organic solvent and even in a small coagulation solution, which prevents the coagulation solution from penetrating from both the inner and outer surfaces, easily forming a void-free layer on the surface. It will probably be formed.

As the polar organic solvent, N-methylpyrrolidone, dimethylformamide, and dimethylacetamide are used.

Mixing ratio of glycols Any ratio may be used as long as the mixed solution can maintain a uniform solution state, but it should be added at least Q, J- or more by weight, and the strainability of the polymer, solvent and blow moldability, etc. It may be determined by taking membrane performance into consideration.

Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight -○○, too, 1oooXtooo-1), flipylene glycol, dipropylene glycol, F dipropylene glycol, polypropylene glycol. Examples include glycerin, trimethylolpropane, and polytetraethylene glycol.

The strength of the polymer Sm as a film forming base is 10-is weight, preferably /J to 30 weight-thin. 3! If the weight exceeds the weight, the water permeability of the resulting semipermeable membrane will become so small that it has no practical meaning, and if the trowel is lower than the weight, the hollow semipermeable membrane will not have sufficient strength. cannot be obtained. Water is most commonly used as coagulation giii, but
It is possible to use organic*S that does not dissolve the polymer (and it is also possible to use a mixture of two or more of these non-SS).Also, it is possible to use a mixture of two or more of these non-SS. a
Using m* is also a gyration.

The aromatic polysulfone hollow semipermeable membrane obtained by this manufacturing method has K11 holes on both the inner and outer surfaces of the hollow fibers, and has a layer with no cavities, and these intermediate layers are also similar to those of the Chen Zhen layer. forms a continuous polymer phase. The pore value gradually increases from both sides of the hollow fiber to the inside of the membrane, and reaches its maximum inside the membrane at approximately the same distance from the two sides of the hollow fiber.

The change in pore diameter takes on a continuous tapered structure from the membrane sui to the inner part. The pores on the inner and outer surfaces are in the range 8/0-1001.

Its diameter varies depending on the average molecular weight of dextran water.
It is estimated based on the constant transmission rejection rate when flowing i and various protein waters St, and observation of the vicinity of both surfaces using a transmission electron microscope. There are differences depending on the spinning conditions near both aiii of the hollow fiber, but from the surface to the inner 11 #/~
! There are no cavities present over a thickness of the order of microns. Cavities may exist in the inner layer of the membrane, which is a polymer phase that is continuous with the layer in the vicinity of 9L#, which is completely free of 9L#. The cavity is.

Membrane T - This is the missing part of the polymer to be carved, and its diameter is approximately 10μ. Therefore, in the present invention,
Those smaller than @ioμ are called pores.

in general! 2! The amount of paulownia decreases when the film thickness is reduced, and when the film thickness is reduced to 100 μm or less, hollow fibers with fewer cavities can be created. Hollow fibers with few cavities are pressure resistant.

It has excellent mechanical strength and good water permeability.

Not only in the absence of cavities, but also in the presence of cavities, there are multiple pores in the inner layer of the membrane.
increases gradually in a chain reaction as it moves inward from the film SUS, and reaches its maximum at a portion equidistant from both am and aPi, and its average diameter is 0.
0j-10μ. The diameter of the pores that reach the inside of the membrane from the membrane e1m increases because condensation occurs from the inside toward the inside, quickly at the surface and slowly at the inside. This is thought to be for the purpose of concentrating. Therefore, the number of pores 11r located at a distance j from the membrane surface toward the circle 11 is j, and for example, polysulfone with a concentration of 10% by weight (union carbide employee, conducted The relationship between I and r is shown as II/llIc for a hollow fiber with a film thickness of 300 microns spun using a dimethylacetamide (DMAC)-tetraethylene glycol system.

This hollow fiber Km depends on the film thickness, but -10~30C-
・Exhibits high water permeability under daily and atmospheric pressure, especially high #kll poly! −
Thin hollow fibers spun with high water permeability.
- For the aromatic polysulfone hollow fibers spun under the same conditions as in *, the water permeability is inversely proportional to the membrane thickness, as shown in the JIIJ diagram for the same medium 9 yarns as shown in II/IQK, and the membrane thickness is thinner. It has been found that the water permeability increases with the increase of water permeability in anisotropic semipermeable membranes such as polyacryminitrile, sulfonated polysulfone, polycarbonate, and cellulose acetate. It is said that the semi-permeable membrane of Chikyoumoto Miwa has resistance to water permeability in all layers from the surface to the inside of the hollow membrane, regardless of whether there is a cavity or not, and the entire thickness of the membrane is water permeable. It is considered that the Furthermore, in aromatic polysulfone hollow fibers with different membrane thicknesses spun under the same conditions, the diameters of the pores on the surface are almost the same, and there are no cavities. The thickness of the layer near the rain is also constant regardless of the film thickness, as confirmed by the rejection rate for dextran and various proteins and the electron microscopic photograph, respectively.
Nevertheless, the fact that water permeability is inversely proportional to membrane thickness indicates that the resistance to hydraulic flow through a membrane is due to the entire membrane thickness, and the 5. * Only one layer (more indeterminate. Furthermore, despite having layers without cavities on both front IIi,
Having a high water resistance will support this.

Inside thus obtained! WJ#! The thread has extremely high water permeability by making it a thin film! and both IIm
To! ! ! Because it has a structure with a moisture-free layer, j! It can be washed, there is less compaction, there are fewer changes during seedling operation (it is convenient to use, and the mechanical image quality is excellent).

In addition, the medium 9th thread after the thin film steel has a small Pziming volume and a large surface area, so if kept, it can be used as a membrane for Pml and artificial kidneys or ascites protein-concentrated membrane. It can also be useful as a filtration membrane for seed birth therapy.

Below is more details from Ii11sf4tc! I will clarify.

Implementation fil.

Dimethyl acetate was selected as an additive, and polysulfone (hereinafter referred to as polysulfone) having a repeating unit that is composed of [selected tetraethylene glycol and polymer] was added as an additive, and 71:1:10 wt. At the opening of the test, the mixture was mixed to make a uniform **.

This polymer Sg was extruded from a layered nozzle for producing hollow fibers, purified water was used as the inner and outer coagulation casings, and the cylindrical polymer Ilt was coagulated from both the inside and outside with a':5 to form a hollow porous membrane. In this regard, the hollow fiber spinning conditions were as follows.

Distance from the nozzle to external coagulation IEt (hereinafter referred to as aerial waterfall travel distance)
and Iej)/, 1 body, The properties of the obtained hollow fiber are as follows, inner diameter 07! -1 outer diameter/, 3jwm, film thickness 0. J■、Water permeability lkomeseng・day・
The cut rates for atmospheric pressure −jc, burst strength j/KVIL”, dextran molecular weight IC,≠X/ri, and 7×10 were 2≠0%, 20.0%, and tJ, 0%, respectively.

Example 2. -15° In the same manner as the 1 ml test, various additives were added.
Yarn # Yarn was done. The additive added to the hollow fiber jI[i[ and the properties of the obtained hollow fiber are shown below.

Comparative Example 1゜Using the same polymer S as in Example 1,
Dr. Plaid Kl#41'00tsnre at 7C
After casting on a gaff plate, it was left to stand for 7 minutes and allowed to solidify in JJC water. The properties of the obtained porous flat membrane are as follows: film thickness J00-, water permeability o, oi (~・day・atmospheric pressure), elastic modulus i3/i<Kg/d), and strength O.
(Hereinafter, Comparative Example 2.3゜Polysulfone 10p, N-methylbio9 donta op#t
The mixture was mixed at 0.degree. C. to obtain a uniform tSC. Place this poured casing on a glass plate and use Dr. Plaid to make a film with a thickness of 30 μm.
I ran away with m. The properties of the obtained porous flat membrane are as follows: thickness: 100 sp*, water permeability: d/d-day/atmospheric pressure, elastic modulus: JIQIld, strength: OKf'd or less.

Hollow fiber yarn j using internal coagulation using INK water
A K1m thread is passed through an Ill-shaped nozzle in the air, and the polymer hollow fiber is coagulated from the inside. The yarn was spun.

The desired hollow fiber membrane has an inner diameter of 0.71wm, an outer diameter of i, and a diameter of 3z.
-1 film thickness 03■, water flow rate j d7d・day・atmospheric pressure jc,
l11 strength / J 1 strength / 01LIld, elastic modulus λ! It was mu-.

Comparative Example 4.5°Polysulfone 2011. 1. Warm dimethylacedoide III as ml and make a uniform moat 1
Using the Honto cabinet, 厘＊S degreeλ! Film thickness using Dr. Plaid at ℃? ! After spraying on a glass plate with Otam,
It was left to stand for 1 minute and coagulated in water at 23°C.

The obtained porous flat membrane had a thickness of 300 μm and a water permeability of QOO.
The atmospheric pressure was λIt.

Under the same hollow fiber spinning conditions as in Example 1 using Hontokan! When the yarn was spun, the properties of the hollow fiber obtained were as follows:
．． 71 so, external characteristics i, ss■, film thickness 0. J-1 Water flow rate 00
/ d7d・day・atmospheric pressure jc, base strength J/Q/
d. Strength! 1(-1 elastic modulus l!kol(-).

In this experiment, dimethylacetamide was used as the 6° polysulfone SS, and tetraethylene glycol was used as the additive, respectively.
i: A uniform solution was obtained by mixing at a ratio of about 100 ml by weight. Book S
* was cast onto a glass plate using Dr. Plaid, and left to stand for 1 minute to solidify in water at 23°C. The resulting porous flat membrane has a thickness of 300 mm and a water permeability! wlld・day・
The atmospheric pressure was 2 ta, C1, the elastic modulus was 2/j tatami, and the strength was 2 tatami.

Comparative Example 7゜10% by weight of sodium nitrate water**to- was mixed with dimethylacetamide λ420 IIt and dimethyl sulfoxide,
A mixture of 1300 **ec, ii+et, and 0 # Ik31 was added to the polysulfone 7 of the example to make a uniform S casing. From this polymer Sm in a similar manner to Example/.

A hollow fiber membrane was obtained. Hollow fiber inner machine 0.7j cabinet.

Outside @ 1.31wm, water permeability/, Owld-day/atmospheric pressure, bursting strength/j El/d, elastic modulus? 2 μv/d,
The strength was 30 stories. Further, the cut rate for dextran with a molecular weight of 7 x / 0' was 4c1%.

Implementation fl16° polysulfone (ps), dimethylacetamide (DMA)
@) and tetraethylene glycol (TgG) were mixed with 1% gold to form a uniform S* and extruded through a nozzle with a hole diameter of S*Sa.
P3@0.7jwxrj outer ll & various film thickness WL
The resulting hollow fibers were cast into fibers. The false conditions are Example 1 and M.

The obtained hollow fiber membrane had a value of 411, an elastic modulus, and a mat. The relationship between the membrane thickness and water permeability of these hollow systems is shown below.

夷jmll17. -21° Botasulfone was used as the polymer, tetraethylene glycol was used as the additive, and the pottery was different from that in Example 1. Show your fake talent and talent.

Conducted IHL ~ 26° Polysulfone concentration was set to DMAc @1 agent'' (T
Using gG, polysulfone and DMAcJ) opening numbers were varied to create pseudogeneric casings with different concentrations of polysulfone, and the hollow fibers were made into filaments in the same manner as the fruit 1111111/. While being beaten! Table 13 shows the II properties of the yarn.

Example 27. ~34, polysulfone (Pg), dimethylamide (DMA)
e) After combining %tetraethylene glycol (TEG) at a ratio of Co 0 Nia/: R to make a uniform S*, extrude the polymer St from a ll-shaped nozzle, and
Using W* water as a liquid and an external coagulation box, the polymer was coagulated from the inside and outside to form a hollow porous membrane. At this time, from the hollow fiber wrapping nozzle to the external casing! The properties of the yarn obtained were examined by varying the running distance. Results 4
c, *vc° is shown.

Implementation of Kansaiwa $135.36゜Example Using core 3 and Oka's spinning X
*The polymer was coagulated using methanol. The obtained hollow fiber has an outer circle @0.7j-1/, J! -1 sulfur i
Good results were obtained in terms of +in degree, water permeability, elastic modulus, and strength.

Good fracture strength, water permeability, and elastic modulus 1 strength were obtained even when the same IIK internal coagulation 111EK methanol and external coagulation were used.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the gray material in the side hole and the distance from the inside of the hollow fiber.
It is a graph showing the relationship between the diameter of the irises and the thickness of the membrane drop. Figure 3 is a graph showing the relationship between the membrane thickness and water permeability of the hollow fiber obtained in the implementation g4it. Tatami is 1m Asahi Kaweiko 1m Co., Ltd. Daichiben Shichiho Shu Doshinkoshi! Ushii Uke J Ding (F) Procedural amendment (spontaneous) December 2r, 1980 Haruki Shimada, Commissioner of the Patent Office 1, Indication of the case 1981 Patent application No. 13/RI0≠2, Title of the invention Relationship with the aromatic polysulfone hollow case case Patent applicant: 4, attorney: 6 Number of inventions increased by amendment: None 7. Subject of amendment: 1. “Detailed explanation of the invention” and “Brief explanation of the drawings” in the specification ■6 Drawing 8, contents of the amendment (as attached) Contents of the license 1, 91 documents (1) 1st oHi line 3 “day and atmospheric pressure !℃" is corrected to "r days/atmospheric pressure (same as water brush 21 C1 and below)". (2) Correct the line "ll3Ill" on the 1st page J to read "Figure 2". (3) Lines 17173 to 16 “Figure 2 is...... Figure 3 is...
It is... '' is corrected as ``Figure 1 is a graph showing the relationship between the membrane thickness and water permeability of the medium 9 yarn obtained in Example/A. The corrections include a slight correction to 1st wA. Figure 2 has been deleted.
Figure 3 shows the disaster in Figure 2.) Patent applicant Toru Hoshino, patent attorney representing Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] (1) After discharging a polar organic solvent solution of an aromatic polysulfone-based polymer containing glycols into a hollow shape from an annular nozzle, the solution is brought into contact with a liquid that is miscible with the mixed solvent but does not dissolve the aromatic polysulfone. A method for producing an aromatic polysulfone hollow semipermeable membrane, which comprises removing the solvent.