JPS58156018A - Polysulfone resin hollow fiber - Google Patents

Abstract

PURPOSE:The titled hollow fiber that has a five-layer structure consisting of the specific outer surface, the outer void layer, the intermediate layer, the inner void layer and the inner surface, thus being suitable for use as a membrane in ultrafiltration, because of its high flux and burst strength. CONSTITUTION:A polysulfone polymer solution containing glycols in a polar organic solvent of 15-35wt% polymer concentration is extruded through annular nozzles. In the meantime, a liquid that is miscible with the above solvent but does not dissolve the polysulfone polymer is used as a coagulant for the outer and inner surfaces and forced into the inside of the hollow part with an appropriate pressure. Then, the resultant fibers are made to run in air at a distance of 0.1-30cm, introduced into the external coagulation bath to produce the objective hollow fiber membranes that have a five-layer structure of the outer surface Ao, the outer void layer Bo, the intermediate layer C, the inner void layer Bi and the inner surface Ai, where the thickness ratio of the inner void layer to the outer one is 1.5-0.6, the total membrane thickness is 100-600mum, the flux is 3m<3>/m<2>.day or more and the fractionating molecular weight is less than 13,000.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polysulfone resin hollow fiber membrane useful as an ultrafiltration membrane, which has high water permeability, high burst strength, and has a novel structure.

Conventionally, there are many documents related to aromatic polysulfone and aromatic polyethersulfone membranes, and there are limited documents disclosing the membrane structure. Regarding this, see Japanese Patent Application Laid-open No. 119-23/ZA3 of Amicon Corporation, L Appl of Gal 7 Saus Research Institute,
, Poly, Sci., 20.2377-239
'1 page and 239.5'-2'lO Otsu page <iq7 in year)
, same < J, Appl, Poly.

Sci,, 2/, 1g13- /900k (/9
1177), etc. The hollow fiber membranes have either a surface layer on the inside or no surface layer on the outside, and the polymer has a void with a size of 70 μm or more on the outside surface. Opening 1
” Therefore, it has disadvantages such as V) low mechanical strength, Q) not being able to be backwashed, and ■ easy clogging. The latter was developed as a support for reverse immersion 6 membranes, and has an average pore diameter of 2! OA~OII has pores with a size of μm, but its water permeability is at most i 3 m7
It is small at m''·daY'atm, and has poor practicality as an ultrafiltration membrane.

JP-A-5TT-13777v, M Kaida 5ll-/y
The aromatic polysulfone and aromatic polyethersulfone hollow fiber membranes described in Publication G of s3yq are both made of inner and outer surface layers, inner and outer void layers, and an intermediate layer, but their mechanical properties are weak, and the intermediate layer is Water permeability is poor due to insufficient communication. Furthermore, in these U) hollow fiber membranes, the lengths of the inner and outer voids are not equal, and the length of the inner void is longer than the length of the outer void. In addition, the permeation resistance near the outer surface is large, and the amount of polymer 1 is large on the outside +1111 and less on the inside, and the mechanical strength against pressure from the inside is low.

Basically, the hollow fiber membrane of the present invention is
Although the structure is similar to that disclosed in Publication No. 39, the thickness of the inner and outer voids is approximately equal, and the polymer particles are evenly distributed, resulting in less resistance and three-dimensional communication with an appropriate thickness. It is different in that it has an intermediate layer with a well-developed structure, and this characteristic G makes it an excellent hollow fiber membrane with high rD-aqueous property and high bursting strength.

That is, the present invention has a 5N structure of an outer surface layer, an outer void layer, an intermediate layer, an inner void layer, and an inner light 101N, and the ratio of the thickness of the inner and outer void layers is /S or less. This relates to a polysulfone resin hollow fiber membrane G having a glaze characteristic.

The present invention will be explained in detail below.

The polysulfone fiber resin forming the polysulfone resin hollow fiber membrane of the present invention is an aromatic polysulfone or polyether sulfone having a repeating unit represented by the following general formula (Il or (II)) (where x, x', "x"x"
plq is/or an integer below the grid, or -C00, ~So,
Solution of H, -N layer 2, etc. tlj M: Represents M substituent. )
These holi sulfones encompass! f. The resin can provide a hollow fiber membrane with excellent heat resistance, acid-alkali resistance, chemical resistance, and mechanical strength.

The hollow fiber membrane of the present invention has a five-layer structure consisting of the polysulfone fiber fingers, that is, an outer surface layer (Ao) and an outer void layer (B).
o)・Intermediate layer (C)・Inner void layer (B, )・Inner & surface layer (
A of Ai). It has a 3N structure of BoCBi Ai.

Although the membrane thickness, outer diameter, and inner diameter of the hollow fiber membrane are not specified,
As the film thickness increases, the bursting strength increases, but the water permeability naturally decreases. The thickness of the hollow fiber of the present invention is approximately 700 to 100
μm, and the outer diameter and inner diameter are determined appropriately based on the membrane thickness and the shape of the hollow fiber.

A of the surface layer of the hollow fiber of the present invention. The A1 layer is essentially the same, and the thickness of the A1 layer is approximately equal and is OO/μm to IOμm, usually about qμ. For example, oO/μm It consists of a bead-like connection of small polymer particles, and the distance between the particles is very narrow near the inner and outer surfaces, and they are packed very densely.As the distance from the surface increases, the distance between the particles increases and the size of the particles also increases. Although the surface layer appears so smooth that no pores can be observed even under an electron microscope, measurements of the permeation rejection when various different dextran aqueous solutions and protein aqueous solutions were flowed showed that the pore size was 10. 'A~100
estimated to be large.

The N layer and the A8 layer are layers that perform a selective permeation function based on the size of permeable molecules. The thinner this layer is, the better the water permeability is. Since the hollow fiber of the present invention has two surface layers, the inner and outer layers, even if a defect occurs on one side for some reason, the molecules to be cut can be prevented from leaking. This has the advantage that the safety in use of the hollow fiber membrane is increased compared to the case of 2, and that the molecular weight cut-off can be sharply rubbed.

B of the hollow fiber of the present invention. Layer B1, when viewed in the transverse direction of the hollow fiber, is a layer in which narrow conical cavities extending straight from the center in the radial direction are lined up at very narrow intervals, and the shape in the fiber axis direction is circular. The hollow fiber has a conical cross-section, which is thinner on the surface side and thicker toward the inside, with the innermost wood end rounded. The length of the void is approximately 70 to 500 μm. The length of this void layer occupies the main length in the film thickness O, but if the voids are too long, the burst strength decreases. The hollow fiber of the present invention has a high bursting strength due to the presence of a layer force, but since the voids in the inner and outer void layers are longer in the radial direction, the permeated liquid does not experience any resistance in this layer thickness and is short-circuited. It has a high water permeability because it can pass through the surface layer and reach the intermediate and surface layers. Therefore, this clan,
It can be said that the B layer contributes greatly to improving the strength and water permeability of the hollow fiber membrane.

Numerous C9 holes (Cp holes will be described later) are opened on the inner wall surface of the void.

It is better that the thicknesses of the B1 layer and the Bo layer are equal. Therefore, the closer the intermediate layer is to the center of the film thickness, the better.

If the thicknesses are different, not only the mechanical strength will decrease, but also the surface layer on the side having a void layer with a longer void length will tend to become thicker and denser than in the case of rupture and compression, which is undesirable. The ratio of the thickness of the inner and outer void layers (eB1/eBo) (hereinafter simply referred to as the inner and outer void ratio) is preferably less than /S, and if it exceeds /S, the mechanical strength will decrease, and the water permeability will also decrease. descend.

Moreover, it is not good if the internal/external void ratio is less than 06.

The hollow fiber of the present invention has an intermediate layer (0 layer). The 0 layer is a single layer of network-structured polymer with cpfL that is well connected in the three-dimensional direction, and the polymer is strongly bonded three-dimensionally to significantly increase mechanical properties such as bursting strength, compressive strength, and tensile strength. This is the contributing layer. The average pore size, when viewed independently, is 0.05 to 10 μm. The thickness of the 0 layer is 5 to 70 μm. This thickness is A. Layer A is very large compared to the thickness of Isso. The C1 pores other than the voids in the hollow fiber membrane are communicating pores, but the inner and outer coatings 1n of the membrane
It increases from 1 to the inside, and reaches its maximum at the 0 layer in the center. Therefore, the water permeability of the hollow fiber membrane is high even with the presence of the zero layer (it can be maintained at a, but still C
M has a higher permeation resistance than layer B, and it is inevitable that the water permeability will decrease considerably in proportion to the thickness of layer 0. 0 layer or 70
When the thickness is more than μm, the permeability is 3 m7m' - d
ay-a tm will be cut off. On the other hand, the thickness of the C layer has a close relationship with the bursting strength of the hollow fiber membrane, and when it is 5 μm or less, the bursting strength is / 5 kg/cl or less.

C of the intermediate layer structure of the conventional hollow fiber membrane and the intermediate layer structure of the present invention
The unit of p-hole is schematically shown in FIG. 77 (support) and (B). In the hollow fiber of the present invention, as shown in (■), the three-dimensional internal penetration of G is significantly improved compared to the conventional one shown in (B). It can exit from the exits (5 Cp holes) in either direction. On the other hand, with the conventional type, the communication is poor, so the liquid coming from above needs to have a limited C
It can only come out through hole 9. For these reasons, the permeation resistance of the intermediate layer of the hollow fiber membrane of the present invention is significantly reduced.

The properties and functions of each layer of the five-layer structure of the hollow fiber of the present invention have been outlined above, and as an example of the present invention, scanning electron micrographs are shown below to show the specific appearance of the hollow fiber of the present invention. reveal.

FIG. 7 is a diagram schematically showing a cross section of the hollow fiber membrane of the present invention. Each figure shows AOlBoXC.

B1 and A1 layers are shown.

FIG. 2 is a frozen-side cross-sectional scanning electron micrograph showing the entire cross-section of seven examples of the hollow fiber membrane of the present invention, and the plane line (approximately gua c1n) at the bottom of the figure represents 500 μm. That is, /1 μm indicates approximately 70 μm.

Figure 3 is a scanning electron microscope 6a photograph of the freeze-fractured cross section showing a part of the total film thickness enlarged.
m') represents 50 μm. In other words, /pantness Sμm is shown.

Fig. 1 is a scanning electron micrograph of a freeze-fractured cross section showing enlarged parts of the A1 layer and the 81 layer. It shows 02μm.

FIG. S is a scanning electron micrograph of seven frozen fractured cross-sections of the inner light...1A1 layer, in which the surface thickness of F section (approximately g) represents 05 μm, that is, /1 rrm represents approximately 00 Z μm.

Figure 3 shows outer surface A. These are scanning electron micrographs of frozen fractured sections of seven cases of blood, where the straight line in F section (approximately 0.5 μm) represents 05 μm, and therefore the line represents approximately 00 μm.

Figure 7 is a scanning electron micrograph of the inner part of the hollow fiber cut obliquely as shown in the figure.
cm,) represents 50 μm, and thus /pharynge represents approximately j μm. What you can see in the photo is the surface of the inner wall of the outer void, and the pore diameter of the C-layer pores gradually increases from the outer surface of the membrane to the inside, and the pattern of the density of the C-layer pores. is clearly visible.

Figure g is a scanning electron micrograph of a frozen fractured cross section showing seven examples of the intermediate layer (C layer), and the F part 1u line (about 0.2 cm) is S
μm and therefore / order indicates approximately O62 μm.

Figure 9 is a scanning electron igl microphotograph of a very large freeze-fractured cross section of the intermediate layer (C layer).
) represents o, sltm, so 7mm is approximately o
, ottμmB is shown. This photograph shows that the C layer pores in the C layer are communicating pores that are extremely well developed three-dimensionally, and that the C layer has a rather three-dimensional network structure.

Table 1 shows data on the thickness, average pore diameter, membrane thickness, and outer diameter of each layer of the hollow fiber G shown in the photographs in Figures 2 to q.

Table 7 (However, the average pore diameter of the Bi layer is measured by scanning electron micrographs of the pores of the C layer other than voids.) It is shown how the radius of the pore changes from the inner surface of the hollow fiber to the outer surface O. It can be seen that the pore diameter increases from the inner and outer surfaces to the center. The manufacturing method will be described later, but the curve -〇- shows the polymer concentration of 77
0% by weight, and the curve -x- shows the case where the polymer concentration is 200% by weight. It can be seen that the pore diameter is smaller when the polymer concentration is higher at 20%, and the structure of the hollow fiber membrane wall is denser. Therefore, increasing the polymer concentration improves the mechanical properties.

In Figure 1, the aromatic polysulfone hollow fibers of the present invention are prepared with various membrane thicknesses, and the relationship between membrane thickness and water permeability is plotted. Furthermore, in FIG. 12, the relationship between membrane thickness and water permeability is similarly plotted for aromatic polyether sulfone hollow fibers. In both of these Examples, a direct proportional relationship is established between the film thickness and the water permeability, and the water permeability almost disappears when the film thickness is 0 or more.

FIG. 73 shows the relationship between the intermediate layer thickness, water permeability, and bursting strength of hollow fibers of the present invention with various intermediate layer thicknesses. It has been shown that as the thickness of the intermediate layer increases, the bursting strength increases by up to 6, and the water permeability decreases as the thickness increases, and that the decrease becomes particularly noticeable from a certain thickness.

73- Note that the C2 hole refers to the polymer monograph Vol-J '1
．． Nα320! -2/l (/977)
) If we consider a very small emulsion of about 100A, such as 100A, and if the Oll or Water is occupied by a polymer concentrated phase or a dilute phase, this is the pore structure that is formed, and the shape as seen from the surface or llr plane is a round circle. A hole is called a hole. On the other hand, a long and narrow hole is called an Up hole.

In the present invention, the internal and external void ratio is defined as follows. From the electron micrograph (magnification: SO ~ 300) of the hollow fiber cut in the longitudinal direction and horizontal plane, we found the inner and outer voids with the largest length, and the center of the hollow fiber and the apex of these voids. The line connecting the upper and lower ends of the void is the inner and outer void length lB1, zB. And this ratio zB,
/A1 is the internal and external void ratio.

Although specific structural photographs and data have been shown above regarding specific examples of the hollow fiber membrane of the present invention, these specific data are not unrelated to the method for producing the hollow fiber membrane of the present invention.

Next, an example of the method for producing the hollow fiber membrane of the present invention will be described.

The polysulfone resin hollow fiber membrane of the present invention is produced by discharging a polar organic solvent solution of a polysulfone polymer containing (poly)ethylene glycol and having a polymer concentration of 15% by weight or more from an annular nozzle in the form of hollow fibers, and mixing with the solvent. A liquid that does not dissolve polysulfone-based polymers is used as the inner and outer coagulating liquid, and the coagulating liquid is injected into the nozzle at an appropriate pressure to cause the air to pass through the air at zero. ! It is obtained by a method for producing a polysulfone fiber resin hollow fiber membrane, which is characterized in that after the fibers have been run for a distance of Cm or more, an external coagulating liquid is passed through the fibers and the fibers are spun to a thickness of 100 to 00 μm.

In this production method G, factors such as the addition of (poly)ethylene glycol to the spinning solution, the polymer concentration of the spinning solution, the air travel distance, and the hollow fiber membrane thickness are closely related to each other, and the bond between them is are extremely important, and even if one of them is missing, the hollow fiber membrane of the present invention cannot be obtained.

As a polar organic solvent, polysulfone Itoki t)? t Can be used as long as it can be completely dissolved, N-methylpyrrolidone, dimethylformamide, especially dimethylacetamide,
Diethylacetamide is preferably used.

In the hollow fiber manufacturing method of the present invention, the addition of (poly)ethylene glycol to the spinning dope is extremely important. Of course, in the case of a polymer solution consisting of a polysulfone polymer and a polar organic solvent, an aqueous solution of a salt as in the inventions of JP-A-51-G3777 and JP-A-5G1/LtJ7Q can be added. In the case where polyvinylpyrrolidone is added, even if a five-layer hollow fiber is obtained, it is necessary to obtain an intermediate layer with extremely good continuity with an inner/outer void layer ratio of /j or less, like the hollow fiber membrane of the present invention has. It is not possible to obtain a hollow fiber membrane that has excellent water permeability, high burst strength, and excellent water permeability. The addition of polyethylene glycol is also associated with the formation of an intermediate layer of structure with significantly lower permeation resistance. This makes it possible to spin hollow fiber membranes from a high-concentration polymer stock solution and significantly improves the mechanical strength of the hollow fiber membranes, compared to conventional techniques.

Examples of the (poly)ethylene glycol used in the method of the present invention include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol (molecular weight: 200, 6001.
! 000, Otsu 000) etc., propylene glycol,
dipropylene glycol, tripropylene glycol,
Polypropylene glycol (molecular weight, 200, Otsu 00
, 2000, Otsu 000), glycerin, trimethylolpropane, polytetraethylene glycol,
and ethylene glycol methyl ether derivatives such as ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, and propylene glycol derivatives such as propylene glycol monomethyl ether. Among them, those having a molecular weight of approximately the same as tetraethylene glycol are preferred.

The addition ratio of (poly)ethylene glycol may be any ratio as long as it maintains a uniform dissolution state of the polymer solution, depending on the polymer concentration, the type of polar solvent used, etc.
It is used in a range of about 05 to 30% by weight, although it varies depending on the situation. If it is less than 0.5%, the effect is small, and if it exceeds 30%, the stock solution becomes unstable, devitrification occurs, and film formation becomes difficult, making it impossible to obtain a good film. Preferably it is j-20 weight%.

The polymer concentration of the film forming stock solution is 75% by weight or more, preferably 75 to 30% by weight, more preferably /f to 23% by weight. If it exceeds 39% by weight, the water permeability of the resulting semipermeable membrane becomes so small that it has no practical meaning,
Furthermore, if the concentration is lower than %/Yujuzuke, the thickness of the intermediate layer will not be sufficient, and only a layer with weak mechanical strength can be obtained.

The polymer concentration in the membrane-forming stock solution has a close relationship with the hollow fiber structure obtained from it. In other words, in the case of a flat membrane, /
When a low concentration stock solution of less than 1% is used, the void layer becomes long and develops in the thickness direction of the film...The J layer (4) and the void layer (
A film having a structure made of Bl is obtained. On the other hand, when a high-concentration stock solution with a concentration of /S or higher is used, an intermediate layer develops as the polymer concentration increases, forming a three-layer structure consisting of a capillary layer, a void layer (Bl), and an intermediate layer (C). A scanning electron micrograph is shown in Figure 1 for reference.However, in any structure, a flat membrane has extremely low water permeability, and it is not possible to obtain a membrane with high water permeability.For reference. 7th
Figure J (This shows the relationship between the film thickness and water permeability of the ABCJ layered flat membrane. It can be seen that the water permeability is extremely small.

On the other hand, when using a low-concentration stock solution for hollow fibers and coagulating both the inner and outer surfaces of the hollow fibers, extremely thin voids in the intermediate layer or irregularly arranged surface layers (A) and void layers (B) Hollow fibers arranged in the order A, Bi BoAo, and G are obtained, but such hollow fibers have weak mechanical strength and cannot withstand continuous operation using backwashing.

In addition, since only one side is brought into contact with the coagulating liquid instead of +1iII+m coagulation, it has a structure in which AB or BA is arranged in the order of AB or BA, which consists of a surface layer (4) with a surface layer of 1m on the inside or outside and a void layer (B). A hollow fiber with a two-layer structure is obtained. However, all of these hollow fibers with a two-layer structure have low mechanical strength and cannot withstand long-term operation using backwashing.

Using a highly concentrated stock solution of 75% by weight or more, it has a five-layer structure with two surface layers, two void layers, and one intermediate layer of appropriate thickness, which is solidified from both sides with appropriate mechanical strength and Hollow fibers with high water permeability can be obtained. In addition, as a reference map, N Ao BOC is shown in Figure 7.
The relationship between the membrane thickness and bursting strength of the S layer structure, A, B structure, and BA layer structure hollow fibers of B1A4 is shown. It can be seen that the bursting strength of the S-layer hollow fiber is definitely superior.

As the coagulating liquid, water is most commonly used, but fEA solvents such as methanol and ethanol that do not bath-dissolve the polymer may also be used.
You may use a mixture of 1 and 2. It is also possible to use a skewer in which the internal and external coagulation liquids are different liquids or coagulation baths with different liquid compositions.

During hollow fiber spinning, coagulation must be carried out on both sides using a coagulation bath both inside and outside the hollow fiber. Og the inner and outer voids
/j, it is necessary to provide an air travel distance to delay contact with the outer coagulation bath, and the air travel distance varies somewhat depending on other spinning conditions G. For example, if the hollow fiber diameter is The thicker the film, the larger it needs to be, but 0. ．． A distance of 5'-, 20 cs is required. i
j;am is particularly good, especially G is preferable.

QJc, below v, the inside/outside void ratio easily exceeds /S < 1
．． If it exceeds 20 on, it becomes difficult to form a film.

Furthermore, even if hollow fibers are manufactured with each of the conditions listed in (h) within the specified range, if the thickness of the hollow fiber is rubbed by less than 700 μG,
Depending on the manufacturing method of the present invention, the hollow fiber having the 5-layer structure of the present invention can be obtained. Thickness is 700μ~OOμ,
The preferred range is 700μ to 00fiL.

Figure 70 shows more specifically (i) Polysulfone (manufactured by Union Carbide) is dissolved in dimethylacetamide-tetraethylene cryfur thread solvent, and the polysulfone concentration is /70% and 20%. .

Seven examples are shown in which the relationship between the distance from the inner and outer surfaces <2+ and the diameter of the pores present (7) is shown in which hollow fibers with a thickness of 300 μm are spun from the stock solution.

It can be seen that the Cp pore radius gradually increases from the surface to the center, and compared to the polymer concentration/70% pore diameter G, the pore diameter in the case of 20% is relatively small.

Next, as an example, manufacturing conditions and properties of hollow fibers obtained under those conditions will be shown. The present invention will be understood more specifically by these numerous examples, and the scope of the present invention is of course not limited to these examples.

Example / Dimethylacetamide was selected as the solvent, detraethylene glycol was selected as the additive, and polysulfone (hereinafter referred to as polysulfone) having a repeating unit represented by the following was used as the polymer.
They were mixed at a ratio of t% to form a uniform bath solution. This polymer solution was extruded from an annular nozzle for producing hollow fibers, and purified water was used as the internal and external coagulating liquids to coagulate the polymer bath liquid from the inner and outer surfaces, thereby spinning a hollow porous membrane. At this time, the hollow fiber spinning conditions were as follows.

The distance from the nozzle to the external coagulating liquid (hereinafter referred to as aerial travel distance) was 7.5', and the properties of the obtained hollow fibers were as follows: inner diameter 0.73 +
arn, outer diameter/3! nan, film thickness Q, 3 nm, water permeability / , :l m'/m' ・day-atm ・water temperature 2K"C, bursting strength 3 / kg/crd, dextran content I-amount 104, 'I x 10' , 7×10' [The corresponding cut rates are 2ii, o%, go, o%, respectively.
%, 30%, and the 111t structure of the obtained hollow fiber is uninvented! ; It showed a layered structure (AoBn CBi Ai ), and the internal/external void ratio was /3.

Examples 2-/S Hollow fiber spinning was carried out in the same manner as in Example 2 with the addition of yuzu additives. Table 2 shows the additives added to the hollow fiber stock solution and the properties of the hollow fibers obtained.

The cross-sectional structure of the obtained hollow fibers was all the five-layer structure of the present invention, and the internal/external void ratio was 10 to /3.

(Left below) Using the same polymer solution as Comparative Example/Example/, the stock solution humidity rs”
After casting on a glass plate with a cc trowel with a film thickness of 10 μm, release it for 1 minute. 2! ;-
Cσ] Solidified in water. The opening properties of the perforated porous 1-millimeter membrane are as follows:
m"/m' day-atm, water temperature, !s'c, modulus of elasticity/3//kqAnl, strength Orqlcr
! Below.

The structure of the obtained flat film was an ABC three-layer structure1).

Comparative Example 13 Polysulfone 109 and N-methylpyrrolidone 90 were mixed using a CG trowel at 30°C to form a uniform solution. Apply this pouring liquid to a glass plate - FO, using a Dr. Plaid to form a film with a thickness of 2.
It was flowed at 50 μm and coagulated in water. The properties of the obtained porous membrane flat membrane are as follows: film thickness: 100 μm, di-water ratio: 3 m''/m' day-atm, wet at 25°C, elastic modulus: 231 kQAT!, and strength: 10 kg AM or less. The structure of the flat membrane was AB membrane structure.

Using this solution and using water as an internal coagulation liquid, fibers were spun in the air from an annular hollow fiber spinning nozzle, the polymer was coagulated from the inside of the hollow fibers with water, and the hollow fibers were spun at an air travel distance of 1525-.

The obtained hollow fiber membrane has an inner diameter Q, 7j; MJJI,
Outer diameter/3! ;mm.

Film thickness Q, 3Tmn, water permeability! ; m7m' day-a
rm・Water temperature, 25'C monovalent cracking strength/31・g/c i,
Strength: 10 kg〆〆, Elastic modulus: 2! ;2149/rJ.

The structure of the hollow fibers that could not be obtained was an ABA structure.

Comparative Example +, r 20 g of polysulfone as a polymer and dimethylacetamide (got) as a solvent were mixed to form a homogeneous solution. This solution M was cast on a glass plate using a Dr. Plaid at a coolant soaking level of j and t"c to a film thickness of 0 μIn for 3 minutes, and left to stand for 7 minutes to solidify in 2 J"C water.

The resulting porous flat membrane had a thickness of 300 μm, a dQ water rate of 0.003 m”/m' day-atm, and a water temperature of 25”.
C, and the membrane structure was an A Hc structure.

When a hollow fiber was spun using this solution under the same hollow fiber spinning conditions as in Example, the m properties of the obtained hollow fiber were: inner diameter Q, 7 j 111 m, outer diameter /33 ran, membrane thickness Q. , 3ml, water permeability 0.0/m7m'day
-ATM/water rM2fc, bursting strength 2/kg/cr
! % strength 33 to 9/c, elastic modulus/3.2/l+
y, 4M. The structure of this hollow fiber is A. BoCBi
Although it had a five-layer structure of Ai, it was not the five-layer structure of the present invention. The internal/external void ratio was /7.

Comparative Example B Polysulfone Dimethylacetamide was used as the solvent, and tetraethylene glycol was used as the additive at 10% each.
:9 weight% by weight was mixed to obtain a uniform bath liquid. This solution was cast onto a glass plate using Dr. Plaid, and then allowed to stand for 7 minutes to solidify in water at 25°C. The resulting porous flat membrane had a thickness of 30011 m and a water permeability of 3 m'/m.
'-day-atrrr water IM2j゛C1 elastic modulus, 2
/! ; kg/l: nl, strength 9 ky/cr&
Met. The structure of the obtained Hei 11 had an AB layer structure.

Flat membranes of various thicknesses were cast using the polymer stock solution by the above method, and the relationship between the water permeability and membrane thickness is shown in Figure 7S.

Comparative Example 7 Sodt&% sodium nitrate aqueous solution 0-2 dimethylacetamide 2t20ml and dimethylsulfoxide/3
In addition to 00 ml of the mixed solvent, add the polysulfone of Example 7! ;09 was added to make a homogeneous solution. A hollow fiber semipermeable membrane was obtained from this polymer solution in the same manner as in Example 1. Hollow fiber inner diameter Q, 73 fl, outer diameter 733 mm, water permeability/Q m7rTE'-day-a (rrr water temperature 25
°C1 bursting strength/5rcy/cl.

Elastic modulus 12/'qA! , strength was 30 kg/ci. Further, the cut rate for dextran having a molecular weight of 7×#)4 was 1%. The monomer structure is AOBOCBj A
The inner/outer void ratio was /7, probably because it had a 51-so structure of i, which was not the one of the present invention.

Example/6 Polysulfone (PS), dimethylacetamide (DMA
c), Tetraethylene glycol (TEG) is mixed at a ratio of 1.20 = 77 = 9 wt% to make a uniform solution, and then extruded through a skewer (inner diameter o, 73 rrtrn). Medium rough yarns with different outer diameters and different thicknesses were spun.Other conditions were the same as in Examples.

The obtained hollow fiber membranes all showed an uninvented five-layer structure,
The internal/external void ratio was 10-/3, and it exhibited excellent bursting strength, elastic modulus, and strength. The relationship between the membrane thickness and water permeability of these hollow fibers is shown in Figure O.

Example 77-2/ A uniform spinning stock solution was prepared using polysulfone as a polymer, tetraethylene glyfur as an additive, and each packaging solvent, and hollow fibers were spun. The spinning conditions were the same as in Example/. The cut rates of the obtained hollow fibers for various dextrans with different molecular weights were almost the same as in Example. Other properties are shown in Table 3. The structure of the hollow fiber is the S-layer structure (A) of the present invention.

BOCBi A4), and the internal/external void ratio is 10~
/3.

Table 3 MMfH stock solution, polysulfone: All rights Solvent: Tetraethylene glycol-20Nia/: 9m [11% Hollow fiber inner and outer diameter 0.73//33km n 14 Water rate: m"/m' day・atm・Water temperature, !5
°C29 - Examples 22-25, Comparative Example g DMAc as polysulfone solvent, TE as additive
Using G, the proportions of polysulfone and DMAc were varied to prepare membrane-forming stock solutions with different concentrations of polysulfone, and hollow fibers were spun in the same manner as in Example. Table 1 G does not show the properties of the N-bonded hollow fibers.

Both membrane structures are A. Although the BoCBiAi five-layer structure was used, the thickness of the C layer in Comparative Example Zanami was as thin as 2 μm, and the C layer was not uniform. There was a disturbance in the layers.

Example 2.2-. In the case of 2j, the thickness of the C layer was as thick as 10 to 70 μm, and both the void layer and the C layer had a uniform structure in part of the polymer, and the internal and external void ratio was 10 to 70 μl.

(Leaving space below) = 30- Table G Effect of polysulfone concentration Air travel distance 1! ; cm Hollow fiber inner and outer diameter 0.75Wn, /, 3 jttan,
Film thickness Q, 3m water permeability: m'/m'day-atm
・Water temperature 23''C Examples 26-3/, Comparative Example 9, IO Polysulfone (PS), Dimethylacetamide (D
MAc) and tetraethylene glycol (TEG) were mixed at a ratio of 20N/'' and 9%, respectively, to form a homogeneous solution.The polymer solution was extruded through an annular nozzle, and purified water was used as an internal and external coagulation liquid to form a homogeneous solution of the polymer. A hollow porous membrane was spun by coagulating it from the inner and outer surfaces.At this time, the air travel distance from the hollow fiber spinning nozzle to the external coagulating liquid was varied, and the properties of the obtained fibers were examined.The results are shown in Table 5. The membrane structures of the obtained hollow fibers are all S-layer structures (
AoBocBiA4), but the one of Comparative Example 9 had a large internal/external void ratio of 20 and a large C layer thickness of 2 μ.

In Comparative Example 10, the thread shape was not hollow because the air travel distance was too long.

Table j Table spinning dope, polysulfone:DMAc:TEG=J□Nia/:9 Hollow fiber outer diameter/3! ;wm, inner diameter 0.73μMn,
,, film thickness 0.3 ntm The thickness of the C layer of Comparative Example 9 is 12
It was μ.

*Water permeability: m7m'・day-atnr water f) xn,
2s" (2 Examples 3.!, 33 Using the same spinning solution as in Examples 26 to 3/, the polymer was completely coagulated using an annular nozzle with an air travel distance of 73 cm and using methanol as the internal and external coagulation liquid. The obtained hollow fiber had an inner and outer diameter of 0.751mm, /3 mm, and had good bursting strength, water permeability, elastic modulus, and strength.

The film structure was the S layer structure of the present invention.

Similarly, good bursting strength, water permeability, elastic modulus, and strength were obtained even when using methanol as the internal coagulating liquid and water as the external coagulating liquid.The membrane structure was the S-layer structure of the present invention. Ta.

Comparative Example // This polymer was used to produce hollow fibers of various sizes using a homogeneous solution of polysulfone, dimethylacetamide, and tetraethylene glycol mixed at a ratio of 1.2:65/s by weight as a stock solution for membrane formation. AoBocBiAl is extruded from an annular nozzle and coagulated on both sides (coagulated from the inside and outside) using water as the coagulation liquid to form hollow fibers with various thicknesses having an S-layer structure of AoBocBiAl. 81% due to single-sided coagulation using
Ai B by using water on the inside and air on the outside.

Hollow fibers having a two-layer structure with various thicknesses were fabricated, and their burst strength was measured, as shown in Figure 1.

Example 317 Dimethylacetamide (DMAc) was selected as the solvent, tetraethylene glycol (TEG) was selected as the additive, and #! expressed as +o-C5-8o20 was selected as the polymer. Polyether sulfone having a return unit (hereinafter referred to as polyether sulfone) is s:/s:2o, respectively.
(%) to form a uniform solution.

This Bomber J bath liquid was extruded from an annular nozzle for producing hollow fibers, and purified water was used as the internal and external coagulating liquids to coagulate the polymer solution from the inner and outer surfaces, thereby spinning a hollow porous membrane. The hollow fiber spinning conditions for this poem were as follows.

Distance from the nozzle to the external coagulating liquid (hereinafter referred to as aerial travel distance)/A; tyn.

The properties of the obtained hollow fibers were as follows.

Inner diameter Q, 7j; mn, outer diameter/33m, film thickness 0.3
1nJB, water permeability/Jm7m' day-atm ・Water iQ, 2! ;''C1 bursting strength J3 kqAr &, 1 tensile modulus / 700 kgAr!, strength 70rxgA1d
, Chi T-su) 5 minutes 10', 'I x 10
', 7X#) The cut rate for 4 is 20%, respectively.
tS%, r2%. The membrane structure was the S layer structure of the present invention, and the internal/external void ratio was /3.

Hollow fiber spinning was carried out in Examples 35 to 3 under the same conditions as in Example 341, with the addition of yuzu additive. Table 4 shows the additives added to the hollow fiber stock solution and the properties of the obtained hollow fibers. The membrane structure was the S layer structure of the present invention, and the internal/external void ratio was 10 to 15.

(The following is a blank space) Comparative Example/2 Using the polymer solution of Example 3, a glass plate-I-
After heating for 7 minutes, it was allowed to solidify in water at 25"C.The properties of the obtained porous flat membrane were as follows. Film thickness: 300 μm, a-water ratio: 0.00/m7m
'day-atm, water temperature, 2S''C0 flat membrane structure is A
It was a BC structure.

Comparative Examples /3, /4' Polyether sulfone 109 and N-methylpyrrolidone wax 09 were mixed with a trowel at 30°C to form a uniform solution. This pouring liquid was cast onto a glass plate using a 200cm Dr. Plaid to a film thickness of 2J07tm. The properties of the obtained porous flat membrane were as follows. Film thickness 100 μm 1 Water permeability 3
m7m'・day-atm・water temperature 25″01 modulus of elasticity, !, 2/kqler!, strength 10kg/c i. The structure of Hei 1 had an AB layer structure.

Using this solution and using water as an internal coagulation liquid, the yarn was spun in the air from an annular hollow fiber spinning nozzle, the polymer was coagulated from the inside of the hollow fiber, and the hollow fiber was spun.

The obtained hollow fiber membrane had an inner diameter of 0.7. ! ;mn, outer diameter/3
j; mm, film thickness 0.3mX+, water permeability 3 m'/m'd
ay-atm-water temperature 25°C1 elastic modulus 323kg1cr
lX bursting strength 10 kg/cr! It was F. The hollow fiber membrane structure was an AlB AO layer structure.

Comparative example/j1/Polyether sulfone 20'J, fj4 as O polymer
Dimethylacetamide 109 was mixed as a medium to form a uniform solution. Using this bath solution, a Dr. Plaid film thickness of 00 μm was cast onto a glass plate at a stock solution temperature of 25°C, and left for 7 minutes. ;”C Coagulated in water.

The resulting porous flat membrane had a thickness of 300 μm and a water permeability of 0.000
J m'7m'-day-am'm' wet 2fc. The flat membrane structure was an ABC structure.

Using this solution, hollow fibers were completely spun under the same hollow fiber spinning conditions as in Example 31I, and the properties of the obtained hollow fibers were as follows: inner diameter Q, ? j; rnm, outer diameter/35, membrane thickness 03, water permeability 0.0/71'/m'-day-atm・
The water temperature was 23'C, and the bursting strength was 3 (Slr!).The hollow fiber membrane structure had a five-layer structure, but the strength was different from that of the present invention.

Example 9 Using the same polymer solution as in Example 3'l, hollow fiber membranes having different inner and outer diameters and different membrane thicknesses were spun using a Yuzu annular nozzle. Figure 72G shows the relationship between the freeness rate and membrane thickness of this hollow fiber membrane.
Burn. Each of the 11 hollow fiber springs had a five-layer structure according to the present invention, and the internal/external void ratio was /3.0 Comparative Example/7 A 30% sodium sulfate BoM solution was added to 14 ml of dimethyl sulfoxide II, and the mixture was homogenized. -M liquid. Polyether sulfone/25 No. containing this ordinary solution was bath-dissolved to obtain a polymer solution. The viscosity of this polymer solution was 7,900 centivoise (20''C). This polymer solution was extruded from an annular nozzle for producing hollow fibers, and coagulated from the inside and outside using water as a coagulating liquid.

The inner and outer diameters of the hollow fibers are 0.7! ; 111111% 7
35 mm, water permeability 2m7m'-day-atm, water 712-CI, bursting strength/3''9AM Th. Also, the cut rate for text run with a molecular weight of 7oooo was 70%.The hollow fiber membrane structure was S Although it had a layered structure, the internal/external void ratio was /7.

Example 30-5! In the same manner as in Example 3, hollow fibers were spun using the polymer bath solution, polyether sulfone, additive tetraethylene glycol G, and the respective solvents.

Table 7 G shows various properties of the hollow fiber obtained. Each of the hollow fiber 1-pattern structures was the 5-layered bamboo structure of the present invention, and the inner and outer void ratios were 10 to 3.

Table 7 Examples S~J, Comparative Example/Ir DMAc, (lx
Using TEG as an additive, polyether sulfone and 1
) By changing the ratio of M A c , stock solutions for membrane formation with different concentrations of polyethersulfone were prepared, and hollow fibers were spun in the same manner as in Example 3I. The properties of the hollow fibers obtained are shown in Table 1. The hollow fiber membrane structures of Examples 5 B to S9 all have the five-layer structure of the present invention, and the internal and external void ratios are 1.
It was 0-lj.

Table r Effect of polyether sulfone concentration Air travel distance llCm Hollow fiber inner and outer diameter 0.73 + contraction, /3! ; rtrm, film thickness Q, 3TTm water permeability rn''/rn' ・day-
a tm Water temperature 25°C Example 60-≦5. 'Comparative example/
9, '20 polyether sulfone DMAc゛, T:EG
Mix them in a ratio of 20 = 77:9 (%) to form a homogeneous solution, and after cooling, extrude the polymer solution from an annular nozzle, use purified water as the internal and external coagulation liquid, The polymer was solidified from the inside and outside and a hollow porous membrane was spun. At this time, the air travel distance from the hollow fiber spinning nozzle to the external coagulation liquid was varied, and the properties of the resulting fibers were examined.

The results are shown in Table 9. Example B O-4S hollow fiber membrane structure G was the S layer structure of the present invention.

Table 9 Spinning stock solution Polyethersulfone:DMAc:TEG
=, 20 near/: 9 (%) Hollow fiber outer diameter 733cm, inner diameter (in order of 11, 7, 5', film thickness 03 Funajun 6 water rate m7rn'
-day-atm-Water temperature, 2s''C Example 6 Otsu, Otsu 7 Using the same spinning Kawahara number as in Examples Otsu O to Otsu S, air travel distance/S trough with annular nozzle, internal and external coagulation liquid The polymer was coagulated using methanol.The obtained hollow fibers had an inner and outer diameter of 0.7!;
Good bursting strength, water permeability, elastic modulus, and strength were obtained. The membrane structure was the five-layer structure of the present invention, and the internal/external void ratio was 10 to /j.

Similarly, good bursting strength, water permeability, elastic modulus, and strength were obtained even when methanol was used as the internal coagulating liquid and water was used as the external coagulating liquid. The membrane structure was the five-layer structure of the present invention, and the internal/external void ratio was 10 to /j.

[Brief explanation of the drawing]

Figure 1: Model cross-sectional view of the hollow fiber membrane of the present invention; Figures 2-
FIG. 9 is a traveling microscope photograph of an example of the hollow fiber membrane of the present invention.
Figure 2 is a cross-sectional view of the entire film, Figure 3 is a cross-sectional view of a portion of the total film thickness,
Fig. J is a partially enlarged cross-sectional view of the A0 layer and 81 layer, Fig. 5 is an A11 sectional view, Fig. 6 is a partial layer sectional view, Fig. 7 is a void inner wall surface view obtained by cutting the hollow fiber diagonally, Fig. g is a stacked cross-sectional view of the C layer, and Fig. 9 is an enlarged cross-sectional view showing the C-layer structure. FIG. 70 is a graph showing the relationship between the distance from the inner and outer surfaces of the hollow fiber and the diameter of existing C9 pores. Figure 1/ is a graph showing the relationship between the membrane thickness and water permeability of polysulfone hollow fibers, and Figure 1.2 is a graph showing the relationship between membrane thickness and water permeability of polyethersulfone hollow fibers. FIG. 73 is a graph showing the relationship between the thickness of the hollow fiber intermediate layer, water permeability, and bursting strength. Figure 111 is a reference diagram showing an electron micrograph of a cross section of a flat membrane with an ABCJ layer structure, Figure 1j is a reference diagram showing the relationship between the membrane thickness and water permeability of an ABC membrane, and Figures 1 and 2 are A and B. . It is a reference diagram showing the relationship between the membrane thickness and bursting strength of a CB1A15-layer hollow fiber membrane and an AB or BA two-layer hollow fiber membrane G. FIG. 17 is a perspective view schematically showing seven units of Cp pores in the intermediate layer structure of the hollow fiber of the present invention in comparison with the conventional one; show. Sai1 Figure Sai2 Figure Sai3 Figure Saito Mouth Sai5 Sai6 Figure Off 0 Age8 Figure O''1 Figure +50 300
Figure MU Thickness (F air) Figure 117 (B) (A) Procedural amendment (method) % formula % 1932 Patent Application No. 12♂ Otsu No. 3 2, Title of invention Polysulfone resin hollow fiber 3, Amendment Relationship with the case involving the patent applicant: 4 agents 3-7 Yotsuya, Shinjuku-ku, Tokyo, Shin Building i6
Number of inventions increased by amendment 7 Contents of amendment to be amended (1) Page 1/13, line 13 to the last line of page 1/13 of the specification (4, brief description of the drawings) are amended as follows. Brief explanation of the drawings Figure 1 is a model cross-sectional view of the hollow fiber membrane of the present invention, Figures 2 to 3 are traveling micrographs of examples of the hollow fiber membrane of the present invention, and Figure 1 is the entire cross-section. , Figure 3 is a cross-sectional view of a part of the total film thickness, Figure 3 is an enlarged cross-sectional view of a part of the Ai layer, B, and Figure 5 is A.
11 sectional view, Figure 6 is A. A J-axis sectional view, FIG. 7 is a void inner wall surface view obtained by cutting the hollow fiber obliquely, FIG. g is a C-layer sectional view, and FIG. 7 is an enlarged cross-sectional view showing the C-layer structure. FIG. 70 is a graph showing the relationship between the distance from the inner and outer surfaces of the hollow fiber and the diameter of the existing C1 pores. Figure 1/ is a graph showing the relationship between the membrane thickness and water permeability of polysulfone hollow fibers, and Figure 72 is a graph showing the relationship between membrane thickness and water permeability of polyethersulfone hollow fibers. FIG. 13 is a graph showing the relationship between the thickness of the hollow fiber intermediate layer, water permeability, and bursting strength. Figure 1 is a perspective view schematically showing the C9 hole/unit of the intermediate layer structure of the inner wall yarn of the present invention in correspondence with the conventional one, (A) is the present invention, (B) is the The conventional one is shown. Figure 1j is A. BoCBiAij layered hollow fiber membrane and AB
It is a diagram showing the relationship between membrane thickness and bursting strength for a two-layer hollow fiber membrane of BA. (II) Amendment of drawings No. 1 I/-1/ #, , /7, all figures deleted, Attachment H
Replace No. 14 with Fig. 1j. Patent Applicant: Asahi Kasei F2 Co., Ltd. Representative Patent Attorney Toru Hoshino (Mi) '10 Figure (A) Commissioner of the Japan Patent Office Aio Wakasugi 1. Description of the case 1982 Patent Application No. 121 Otsu No. 3 2 Title of the invention Polysulfone resin hollow fiber 3, Person making the amendment Relationship to the case Patent applicant 4, Agent address 3-7 Yotsuya, Shinjuku-ku, Tokyo Katsu new building jB6
Number of inventions increased by amendment None 7. The description of the description of the contents of the amendment in the column ``Details of the invention?'' of the specification to be amended shall be supplemented as follows. "Figure 17" is corrected to "Figure 111t". (2) Lines '17120-8193j/'Scanning electron micrographs are shown in Figure 7 for reference.'
Delete the description. (3) On the first page, lines 3 to j, delete the statement ``For reference, ABC in Figure 1j is small.'' (4) On page 20, lines 2 and 3, "In addition, as a reference figure, Figure 16 is shown" is corrected to "Is figure is,". (5) Page 27, line 13 to line lj [Bo IJ w-undiluted solution...shown in Figure 1j. ” will be deleted. (6) 3rd≠Page line [Figure 11-1 is corrected as ``Figure 1j.'' Patent Applicant: Asahi Kasei Industries Co., Ltd. Representative Patent Attorney Toru Hoshino Procedural Amendment (Voluntary) 1. Indication of the case 1982 Patent Application No. 12863 2 Title of the invention Polysulfone resin hollow fiber 3 Relationship to the case by the person making the amendment Patent applicant 4 Address of the agent Katashin, 3-7 Yotsuya, Shinjuku-ku, Tokyo Building 5B
6. The number of inventions will not be increased due to the amendment. 7. Full text of the specification subject to the amendment, drawing 8. Contents of the amendment (as attached) Contents of the amendment ■. The amendment will be made as per the full text of the revised description attached to the description. ■0 Drawings Figures 11, 12, 14, and 15 have been deleted, and the attached Figures 11, 12, 14, 15, and 16 have been deleted.
Add Figure 17. However, FIGS. 14 and 15 refer to FIGS. 14 and 15, respectively, which were originally attached to the application. Description A Name of the invention Polysulfone resin hollow fiber λ, Claim (1), Outer surface layer, Outer void layer, Intermediate layer, Inner void layer,
A polysulfone resin hollow fiber membrane having an S-layer structure as an inner surface layer and having a thickness ratio of inner and outer void layers of less than or equal to is. (2) 8. The polysulfone resin hollow fiber membrane according to claim 1, wherein the thickness of the intermediate layer is spm or more and 70 μm or less. (3) The polysulfone resin hollow fiber membrane according to claim 7, wherein the total membrane thickness is /00p8-A007an. (4) The water permeability of the membrane is 3 m”/@”-day-atm
The polysulfone resin hollow fiber membrane according to claim 1, which is as described above. (6) The polysulfone resin hollow fiber membrane according to claim 1/-7, wherein the polysulfone resin is aromatic polysulfone or aromatic polyethersulfone. (7) The concentration of polymer containing glycols is /% by weight
The above polar organic solvent solution of the polysulfone polymer is discharged from an annular nozzle in the form of a hollow fiber and mixed with the solvent,
A liquid that does not dissolve the polysulfone polymer is used as the inner and outer coagulating liquid, and the coagulating liquid is injected from the inside of the nozzle at an appropriate pressure to cause the air to reach zero. ! After traveling a distance of 1 cm or more, the hollow fiber was placed in an external coagulation solution and the thickness of the hollow fiber was approximately /θO~AOOμ.
A method for producing a polysulfone-based resin hollow fiber membrane, which comprises spinning the membrane so that the fibers have a diameter of m. 3. Detailed Description of the Invention The present invention relates to a polysulfone resin hollow fiber membrane having a novel structure, useful as an ultrafiltration membrane, having high water permeability and high burst strength, and a method for producing the same. Conventionally, there are many documents related to aromatic polysulfone and aromatic polyethersulfone membranes, but there are limited documents disclosing the membrane structure. Regarding a membrane having a support layer consisting of a surface layer and a void layer, Amicon Corporation's JP-A-Sho Q9-. Publication No. 23/13, Gulf
South Research Institute J, Appl.
Po1y, Sci, 20. 2377-23 free pages and 239! i~2'IOA page (tqqt, year), same < , LAppl, Poly, Sci,. There are pages such as /gg3~i'yoo (/97?). The former hollow fiber membrane has a surface layer on the inside, but does not have a surface layer on the outside, and a cavity in which the polymer is missing to a size of /Qlnn or more opens on the outside surface. Therefore, ■ mechanical strength is low, ■ backwashing is not possible, and ■ clogging occurs easily.
It has the following disadvantages. The latter was developed as a support for reverse osmosis membranes, and has pores on its surface with an average pore size of 50A to 50A, but its water permeability is at most i3.
The VTR is as small as 7m-day-atm, and is of little practical use as an ultrapolar membrane. JP-A Sho S Dart 93 Fufufu issue, JP-A Sho S Dar/Da 537
The aromatic polysulfone and aromatic polyethersulfone hollow fiber membranes described in Publication No. 9 are both made of inner and outer surface layers, inner and outer void layers, and an intermediate layer, but their mechanical properties are weak and the intermediate layer is Water permeability is poor due to insufficient communication. Furthermore, these hollow fiber membranes have a thickness ratio of inner and outer void layers greater than 75 times, and the thickness of the inner void layer is greater than the thickness of the outer void layer. Therefore, since the amount of polymer is large on the outside and small on the inside, the permeation resistance near the outer surface is high and the mechanical strength against pressure from the inside is low. The hollow fiber membrane of the present invention is basically JP-A-Shosy-/'I
! It has a structure similar to that disclosed in R379, but there is no big difference in the thickness of the inner and outer void layers, and the amount of polymer is almost uniformly distributed, so the resistance is small and the average It is different in that it has a well-developed structure in which pores of the same diameter are connected three-dimensionally, and it also has an intermediate layer of appropriate thickness.This feature provides high water permeability and excellent bursting strength. It is a hollow fiber membrane. That is, the present invention has a film thickness of 100 to 1.00 pm and has a five-layer structure of an outer surface layer, an outer void layer, an intermediate layer, an inner void layer, and an inner surface layer, and Thickness ratio is 7
The present invention relates to a polysulfone resin hollow fiber membrane characterized in that S is less than or equal to 06 or more. The present invention will be explained in detail below. The polysulfone resin forming the polysulfone resin hollow fiber membrane of the present invention is an aromatic polysulfone or an aromatic polyether sulfone having a repeating unit represented by the following general formula (1) or (I[) (however, x, x', X',
X″, X″″, and XJml are each independently substituted with a non-dissociative substitution such as a lower alkyl group selected from methyl, ethyl, n-propyl, and n-butyl, and a halogen group selected from F, CI, I, and Br. group or a dissociative substituent such as C0OH-5OsH, NH2, etc., where l, 01% n -0% p -q represents an integer from O to G. These aromatic polysulfone resins It is suitable that the number average molecular weight of S - measured by an osmotic pressure method is from s, ooo to 100,000. The hollow fiber membrane of the present invention has a five-layer structure made of the polysulfone resin, that is, an outer surface layer (Ao) and an outer void layer (Bo
)・Intermediate layer (C)・Inner void layer (B, )・Inner surface layer (A
i) A. It has a five-layer structure of BocBIAl. As the membrane thickness increases, the bursting strength increases, but the water permeability naturally decreases. The thickness of the hollow fiber of the present invention is approximately 100 to AOOpm.
The outer diameter and inner diameter of the hollow fiber according to the present invention are not critical, but it is generally preferable that the outer diameter is about twice the inner diameter, and therefore the present invention The preferred outer diameter of the hollow fiber is about 30θ to 5oo
The outer diameter and inner diameter (0 μm) are determined to appropriate values depending on the membrane thickness and the shape of the hollow fiber. A of the surface layer of the hollow fiber of the present invention. The layer A1 has almost the same layer structure, and its thickness is A. The thickness of the Ai layer is approximately equal to 0.07 to 70, and the thickness is usually about qμm. For example, it consists of a bead-like connection of small polymer particles of about OQ/IEn, and the distance between the particles is very narrow near the inner and outer surfaces, and they are packed very densely. growing. The inner and outer surface layers appear so smooth that no pores can be observed in the vicinity of their surfaces, even when viewed with a scanning electron microscope. It has pores with a molecular weight cutoff/3,000 or less, and the pore size is estimated to be in the region of ultrap membranes of approximately 10A to 10Ox. This means that dextran with an average molecular weight of 70% or more is cut. this person. The layer, Aid Ld, is a layer that performs a selective permeation function based on the size of permeable molecules. The thinner this layer is, the better the water permeability is. Since the hollow fiber of the present invention has two surface layers, the inner and outer layers, even if one of the layers is defective for some reason, the molecules to be cut can be prevented from leaking. It has the advantage of increasing safety in use of the thread membrane and sharpening the molecular weight cutoff. There are countless voids 1' in contact with the A1 layer. A void is a portion where the polymer is missing and has a conical shape. When viewed in cross-section of the hollow fiber, this void has a narrow conical vertical cross-sectional shape extending straight in the radial direction from the center of the hollow fiber, and therefore, when viewed in a cross-section along the length of the hollow fiber, it is observed to have an approximately circular shape. All voids in contact with the A1 layer point toward the A4 layer,
The hollow fiber becomes thicker toward the inside, and the inner end of the hollow fiber has a rounded shape. When observing the overall state of existence of these voids in a cross section of the hollow fiber, the voids exist in a ring shape surrounding the A1 layer and having approximately the same thickness. The ring formed by these voids is referred to as a void layer (B1 layer) in the present invention. In contact with the partial layer, countless voids similar to those described above exist separately, forming another void layer (Bo layer). In this void layer, all the voids exist with their apexes facing the 9th layer side. The thickness of each void layer is defined as the thickness of a straight line drawn in the radial direction from the center of the hollow fiber and the thickness of each void layer in a scanning electron micrograph of a cross section of the hollow fiber taken perpendicular to the fiber axis of the hollow fiber. The distance between the points where the inner and outer peripheries of a ring formed by a large number of voids intersect. The inner and outer circumferences are determined as follows. First, the outer circumference of the Bi layer is determined as follows. In a scanning electron micrograph (sO ~ 300x) of the entire cross section of the hollow fiber,
Ac1 extending radially from the center of the hollow part is 6
Draw two radiation fractions, measure the distance between the inner edge of the layer and the center of the hollow part of the void that extends deepest into the layer among the voids existing in one radiation fraction, and measure this distance. is performed for each of the six radiation fractions to obtain six values. next,
Draw another 6 radiation fractions with the phase of each fraction shifted by 10° in the clockwise direction, obtain 6 values in the same way as above, and then change the phase of each fraction again clockwise by θ0. Shift and obtain 6 more values in the same manner as above. The arithmetic mean of the total 1 g values obtained in this manner is taken as the radius, and the circle drawn around the center of the hollow part of the cross section of the hollow fiber in the above-mentioned scanning electron microscope photograph is taken as the outer periphery of the Bi layer. The inner periphery of the Bo layer is obtained by the same method as above. Inner periphery of Bi layer and B. The outer periphery of the layer is [A for the former, the boundary line with the layer, and A for the latter. The boundary lines with the layers are the inner and outer peripheries of each layer. This boundary line is clear and easily discernible. The void thickness Fi is approximately 10 to 370 μm. The thickness of this void layer occupies a major portion of the film thickness, but if the voids are too thick, the bursting strength will decrease. The hollow fiber of the present invention has a high bursting strength due to the intermediate layer, but since the voids in the inner and outer void layers are long in the radial direction, the permeated liquid short-circuits and passes through this membrane thickness area without any resistance. , the water permeability is high because it can reach from the surface layer to the intermediate layer/surface layer. Therefore, this B. It can be said that the Bi layer greatly contributes to improving the mechanical strength and water permeability of the hollow fiber membrane. Innumerable Cp holes (C, holes will be described later) are opened on the inner wall surface of the void. Ratio of thickness between Bi layer and Bo layer #r! The closer it is to /, the more preferable it is. Therefore, the closer the intermediate layer is to the center of the film thickness, the better. If the thicknesses are different, the mechanical strength not only decreases, but also the void layer with the longer void length tends to become thicker and denser, which is not preferable. The ratio of the thickness of the inner and outer void layers (A!Bi/j!'Bo) (hereinafter simply referred to as the inner and outer void layer ratio) is preferably less than or equal to tttis. rate also decreases. Furthermore, if the inner/outer void layer ratio is less than 0.6, the water permeability decreases, making it unusable. The hollow fiber of the present invention has an intermediate layer (6 layers). The 6th layer is voids existing in the Bi layer and B. It means an intermediate layer defined by voids present in the layer, and the thickness of the thinnest part of the layer is defined as the thickness of 6 layers, and the thickness of the 6 layers is 5 to 70 μm. The measurement of the thickness of the six layers is carried out on a scanning electron micrograph (ho~3,000x) of the entire cross section of the hollow fiber cut in a plane perpendicular to the yarn axis. The 6th layer is a network-structured polymer layer with Cp pores that are well connected in three dimensions, and the polymers are strongly bonded in three dimensions, significantly increasing mechanical properties such as bursting strength, compressive strength, and tensile strength. This is the layer that contributes to The pore size, viewed independently, is 07-9 μm in average pore diameter. The thickness of the 6 layers is 5 to 70 μm. This thickness is A0
This layer is very large compared to the thickness of the Ai layer. The nine pores other than the voids in the hollow fiber membrane are communicating pores, which become larger from the inner and outer surfaces of the membrane toward the inside, reaching the maximum in the six central layers. Therefore, the water permeability of the hollow fiber membrane can be maintained at a large value even with the presence of the 6 layers, but the 6 layers still have a higher permeation resistance than the B layer, and the water permeability is considerably lower in proportion to the thickness of the 6 layers. A decline is inevitable. 6 layers are 70μm
When the thickness exceeds, the permeability u j tr+7m'-
Day-ATM will be turned off. On the other hand, the thickness of the 6 layers has a close relationship with the burst strength of the hollow fiber membrane, and when it is less than 3 m, the burst strength becomes less than u /s kqAnI. The bursting strength is /! ; If it is less than kg/cJ, it cannot withstand long-term continuous operation. As is clear from the definition of the thickness of each layer of A1XB1%C, BosAo, A1, B1, CXBo, ,
o The total thickness of each layer does not necessarily match the film thickness. C of the intermediate layer structure of the conventional hollow fiber membrane and the intermediate layer structure of the present invention
The l unit of the p-hole is schematically shown in Figures 77 and 77 (B). In the hollow fiber of the present invention, as shown in (A), the three-dimensional internal penetration is significantly improved compared to the conventional one shown in (B), so the permeated liquid entering from the upward arrow is It can exit from the exit in either direction (3-Cp holes). On the other hand, since the conventional type has poor Fi connectivity, liquid entering from above can only exit through the limited C9 hole in search of an exit through which it can pass. For these reasons, the permeation resistance of the intermediate layer of the hollow fiber membrane of the present invention is significantly reduced. The properties and functions of each layer of the five-layer structure of the hollow fiber of the present invention have been outlined above.Next, a scanning electron micrograph of a cross section of a hollow fiber membrane obtained in an example of the present invention, which will be described later, is shown.
The specific form of the hollow fiber of the present invention will be clarified. FIG. 1 is a diagram schematically showing a cross section of the hollow fiber membrane of the present invention. A is shown in each figure. ,Bo,C. Bi and Ai layers are shown. Figure 2 is a frozen side cross-sectional scanning electron micrograph showing the entire cross-section taken perpendicular to the fiber axis of seven examples of the present invention hollow fiber membranes obtained in the examples/examples described below (with different magnifications). 3 times), and the straight line at the bottom of the figure (approximately 7 crn) is 500μ
represents m. That is, /■ is approximately 10. Indicates Aμm. Figure 3 is a scanning electron micrograph (magnification: 330x) of a frozen fractured cross section showing an enlarged part of the total film thickness, and the straight line at the bottom of the figure (approx. In other words, 5 μm is shown in Fig. 7. A scanning electron micrograph JIC (magnification i, yoo) of a freeze-fractured cross section showing a part of the A1 layer and the Bi layer enlarged.
, and the straight line at the bottom of the figure (approximately g fl ) ij , j−
/W represents approximately 0.6 μm. FIG.
! (about g 111M) l;j Q j; pm 2
The surface is approximately 0.04 μm. Figure 6 is a scanning electron micrograph (magnification/@000x) of seven examples of frozen fractured sections of the outer surface label layer, and the lower straight line (approximately g
wa) represents Vios ptr+, and Gatte/III+ indicates approximately 0.01 μm. -fl- Figure 7 is a scanning electron micrograph (magnification: 90x) of the circular inner part of the hollow fiber cut obliquely as shown in the figure.
The lower straight line (approximately lθcIn) represents 50 pnr, so /l1llI represents approximately 5PI11. What is visible in the photograph is the inner wall surface of the outer void, and it clearly shows how the diameter of the C2 pores gradually increases from the outer surface of the membrane toward the inside, and the pattern of the density of C9 pores. FIG. 3 is a frozen-fractured cross-sectional scanning electron micrograph (magnification illθO times) showing seven examples of intermediate layers (6 layers), and the lower straight line (approximately θg cm ) represents kptm, and therefore /
- indicates approximately 062 μ votes. Figure 9 is a scanning electron micrograph (magnification: 1A000x) of a very large frozen fractured surface of the intermediate layer (6 layers).
The lower straight line (approximately 13 m) represents uo, sp*, and therefore /W represents approximately θθ daP. This photograph shows that six layers of C9 pores are communicating pores that are extremely well developed three-dimensionally.
It can be seen that the 6 layers form a rather three-dimensional network structure. Table 1 shows data on the thickness of each layer, average pore diameter, membrane thickness, and outer diameter of the hollow fibers of the examples shown in the photographs of FIGS. 2 to 9 above. Table 1 (However, B1 and the average pore diameter of the electric layer are those measured by scanning electron micrographs of C1 pores existing between voids in the void layer.) Figure 10 shows the results of two implementations. An example of how the radius of the Cp pore changes from the inner surface to the outer surface of the hollow fiber is shown. It can be seen that the pore diameter increases from the inner and outer surfaces toward the center. The method for manufacturing the hollow fiber of the present invention will be described later, and the curve -〇- shows the case where the polymer concentration/'10% by weight, and the curve -x- shows the case where the polymer concentration is 20.0% by weight. The pore size is smaller at 20@@%, which has a higher polymer concentration.
It can be seen that the pores of the hollow fiber membrane are dense. Therefore, increasing the polymer concentration improves the mechanical properties. FIG. 1I shows a plot of the relationship between membrane thickness and water permeability for aromatic polysulfone hollow fibers of the present invention and comparative examples prepared with various membrane thicknesses. In Figure 11, the curve -
O- indicates the case where the polymer concentration is 20.0% by weight, and curve -Δ- indicates the case where the polymer concentration is 15.0% by weight, and is for the hollow fiber of the present invention. On the other hand, the curves - - are for comparative hollow fibers obtained by spinning at a polymer concentration of 13.0% by weight without adding glycols. FIG. 12 plots the relationship between membrane thickness and water permeability for the aromatic polyether sulfone hollow fiber of the present invention. From FIG. 1I and FIG. 1, it can be seen that in the case of the hollow fiber of the present invention, there is a directly proportional relationship between the membrane thickness and the water permeability. FIG. 73 shows the relationship between the intermediate layer thickness, water permeability, and bursting strength for hollow fibers of the present invention made with various intermediate layer thicknesses. In FIG. 13, the curve -x- indicates the water permeability, and the curve -0- indicates the bursting strength of 17-. It has been shown that the bursting strength increases as the thickness of the intermediate layer increases, and that the water permeability decreases as the thickness increases, and that the decrease becomes particularly noticeable from a certain thickness. In addition, the above-mentioned Cp hole is referred to in Polymer Proceedings Vol. 1. ．． ? 4!
, t4nJ θ left ~ 2/A (/977)
oo Considering a very small emulsion in the first place, Oil
Or, it refers to a pore structure formed when Vhter is occupied by a polymer dense phase or dilute phase, and the pore has a round shape when viewed from the surface or cross section. On the other hand, a long and narrow hole is called an Up hole. In the present invention, the inner and outer void layer ratio refers to the thickness of the inner void layer of the aromatic polysulfone resin hollow fiber membrane of the present invention, 1B.
i) and the thickness of the outer void layer 1Bo), i.e. eB,
/ It refers to IBo. 41 and lB. is determined by the method described above. Internal and external void layer ratio Fi13~θ of the aromatic polysulfone resin hollow fiber membrane of the present invention
6, preferably dl'l to lO. Specific implementation of the hollow fiber membrane of the present invention-ig:
- For example, specific structural photos and data are shown, but
These specific data are not unrelated to the method for producing the hollow fiber membrane of the present invention. Next, an example of a method for manufacturing the hollow fiber membrane of the present invention will be described. The polysulfone-based resin hollow fiber membrane of the present invention is capable of discharging a polar organic solvent solution of an aromatic polysulfone-based resin with a concentration of polysulfone resin containing glycols from 1 to 35% by weight, so that the inner width of the polymer discharge annular groove on the discharge surface is / 10-700
Pra is discharged in the form of a hollow fiber into the air from an annular nozzle, and at the same time it is mixed with the above solvent, but a liquid that does not dissolve the polysulfone resin is injected from inside the nozzle as an internal coagulation liquid, and then mixed with the above solvent, but does not contain aromatic Provided is a method for producing an aromatic polysulfone resin hollow fiber membrane, which includes introducing the hollow fiber discharged body into a coagulating liquid bath made of a liquid that does not dissolve the group polysulfone resin. In this production method, various factors such as addition of glycols to the spinning solution, polymer concentration in the spinning solution, aerial travel distance, and hollow fiber membrane thickness are closely related to each other, and their bonding is extremely important. Even if one is missing, the hollow fiber membrane of the present invention cannot be obtained. Any polar organic solvent that can dissolve the polysulfone resin can be used, but N-methylpyrrolidone, dimethylformamide, particularly dimethylacetamide, and diethylacetamide are preferably used. In the hollow fiber manufacturing method of the present invention, the addition of glyfurs to the spinning dope is extremely important. Of course, in the case of a polymer solution consisting only of a polysulfone polymer and a polar organic solvent, JP-A-Sho! When adding an aqueous solution of a metal salt of an inorganic acid or a metal salt of an organic acid as in the inventions of II-/113777 and JP-A-13379, or when adding polyvinylpyrrolidone! Even if a hollow fiber with a five-layer structure is obtained, the hollow fiber membrane of the present invention has an intermediate layer with extremely good continuity with an inner and outer void layer ratio of /S or less, and has high burst strength and excellent water permeability. A hollow fiber membrane with excellent properties cannot be obtained. The addition of Glyfurs is also associated with the formation of an intermediate layer of structure with significantly lower permeation resistance. This makes it possible to spin hollow fiber membranes from a high-concentration polymer stock solution, and significantly improves the mechanical strength of the hollow fiber membranes, compared to conventional techniques. The hollow fiber membrane according to the present invention obtained in this way has a water permeability of 3 d/la"・day-atm or more and a burst strength/
! ; kg7tt1 or more, tensile strength 26)9/cI
It has excellent properties of J or higher [measured with Takasago Autograph 1M-10θ (Tensile Testing Machine manufactured by Takasago Manufacturing Co., Ltd., Japan)]. Glycols used in the method of the present invention include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight θθ~booo), propylene glycol, dipropylene glycol, triple pyrene glycol, polypropylene glycol, etc. (Molecular weight -
〇〇-AOOO), chrycerin, trimethylolpropane and ethylene glycol methyl ether derivatives such as hyethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol 7-methyl ether, diethylene glycol 21-dimethyl ether, triethylene glycol monomethyl ether, and furopylenge. Examples include propylene glycol derivatives such as recall monomethyl ether. The above grifols may be used alone or in a mixture. Among them, those having a molecular weight of approximately the same as tetraethylene glycol are preferred. The addition ratio of Glyfurs may be any ratio as long as it can maintain a uniform dissolution state of the polymer solution, and it varies depending on the polymer concentration, the type of polar solvent used, etc., but it is used in the range of about 0.05 to 30% by weight. It will be done. If it is less than 0.5%, the effect is small, and if it exceeds 30%, the stock solution becomes unstable, devitrification occurs, and film formation becomes difficult, making it impossible to obtain a good ID. #i is preferably 3 to 20% by weight, more preferably 5 to 75% by weight. Polymer concentration of film forming stock solution #1/S ~ 35% by weight or more,
Preferably t;j is 1g-23mli%. 35
If it exceeds % by weight, the water permeability of the resulting semipermeable membrane will be so small that it has no practical meaning, and if the concentration is lower than % by weight, the thickness of the intermediate layer will not be sufficient, and the average thickness of the intermediate layer will decrease. The pore diameter exceeds 97 Jn, and only those with weak mechanical strength can be obtained. The polymer concentration in the membrane-forming stock solution has a close relationship with the hollow fiber structure obtained from it. In other words, in the case of a flat membrane, 7
When a low concentration stock solution of less than 3% by weight is used, the surface layer (AI) and the void layer (B
) is obtained. On the other hand, when using a high-concentration stock solution of /j heavy plate or higher, an intermediate layer develops as the polymer concentration increases, and a three-layer structure consisting of a surface layer (A), a void layer (B), and an intermediate layer (0) is formed. This structure is shown in Figure 1 of the scanning electron micrograph. However, in either structure, a flat membrane has extremely low water permeability, and a membrane with high water permeability cannot be obtained. Figure 7S The relationship between the membrane thickness and water permeability of the ABCJ layered flat membrane is shown in Fig. 1S. It can be seen from Figure 1S that the water permeability is extremely small when the membrane thickness is more than iooμm.On the other hand, with hollow fibers, low concentration stock solution is When the inner and outer surfaces of the hollow fiber are coagulated, the hollow fiber is formed in the order of Ai Bi BoAo, consisting of the surface layer (A) in which extremely thin voids in the intermediate layer are irregularly arranged, and the void layer (B). However, such hollow fibers have weak mechanical strength and cannot be used for continuous operation using backwashing.In addition, by contacting only one side with the coagulating liquid instead of coagulating both sides, it is possible to A hollow fiber with a two-layer structure consisting of a surface layer (A) with a surface layer and a void layer (B) arranged in the order of AB or HBA can be obtained.However, these hollow fibers with a two-layer structure However, the mechanical strength is weak and cannot withstand long-term operation using backwashing.By using a high concentration stock solution of /S weight i% or more and coagulating it from both sides, one surface layer, one void layer, and a suitable A hollow fiber with appropriate mechanical strength and high water permeability can be obtained using a five-layer structure with seven intermediate layers of a certain thickness. The relationship between the membrane thickness and bursting strength of the AB layer structure and BA layer structure hollow fibers is shown.It can be seen that the bursting strength of the S layer structure hollow fibers is by far superior. A hollow fiber is discharged into the air from an annular nozzle with an inner width of /10 to 700 pm.It is approximately determined by the film thickness of the hollow fiber and the width of the discharge annular groove of the annular nozzle used. It is not affected much depending on the conditions.The film thickness is
Usually, the groove width is thinner than the above groove width, and the groove width is usually between /10 and above. By using an annular nozzle having an inner width of the polymer discharge annular groove of 00 pm, lθO~A0
Hollow fibers with a membrane thickness of 0 pTn can be obtained. As the coagulating liquid, slag and water are most commonly used, but organic solvents such as methanol and ethanol that do not dissolve the polymer may also be used, or a mixture of one or more of these non-solvents may be used. It is also possible to use different internal and external coagulating liquids or coagulating baths with different liquid compositions, but preferably the internal coagulating liquid and the coagulating bath liquid are the same. During hollow fiber spinning, a coagulation bath must be used inside and outside the hollow fiber to effect coagulation on both sides. In order to maintain the inner/outer void layer ratio at θ~15, it is necessary to provide an air travel distance to delay contact with the outer coagulation bath, and the air travel distance varies somewhat depending on other spinning conditions, for example, The thicker the hollow fiber diameter and the thicker the membrane thickness, the smaller it needs to be, and the range of niboO/~jOcm is preferable. 01cm
If it is less than 30I, the inner and outer void layer ratio tends to exceed 5.
If it exceeds In, it becomes difficult to form a hollow fiber without deformation. In order to obtain a hollow fiber supporting the S-layer structure of the present invention, the film thickness must be 10θ to Aoopm, preferably 100-'1001
It is designed to be 1m. Even if hollow fibers are manufactured with each of the above conditions within the specified ranges, if the thickness of the hollow fibers is less than 100 μm, the hollow fibers having the five-layer structure of the present invention cannot be obtained by the manufacturing method of the present invention. . More specifically, Fig. 7θ shows the film thickness obtained by spinning a stock solution in which polysulfone (manufactured by Union Carbide) was dissolved in a dimethylacetamide-tetraethylene glycol solvent, and the polysulfone concentration was 770% by weight and 20Mj1%. Distance from the inner and outer surfaces of a 300 μm hollow fiber (
Seven examples are shown in which the relationship between 1) and the diameter (r) of existing pores is plotted. -Co-2- It was found that the C9 pore radius gradually increases from the surface to the center, and that the pore diameter at 20% polymer concentration/'10% pore diameter is relatively much smaller. Ru. The aromatic polysulfone resin hollow fiber membrane according to the present invention is made of globular proteins and molecules! Things less than /aθOO can pass through, but things beyond that, such as albumin, globulin, nitrogen substances contained in body fluids, and bacteria (/aθOO) can pass through.
~λμmK), yeast (-~1μm), and pathogenic viruses (molecular weight: 10,000 yen) are impermeable, so it is useful for removing chloridene substances from injections and infusions, producing ultrapure water, and protein substances. In addition, it is particularly advantageous in applications that require repeated high-temperature sterilization of membranes and sterilization with acids, alkalis, etc. during membrane purification, such as the purification of pharmaceuticals and foods, and the production of ultrapure water. It will be done. Next, as an example, manufacturing conditions and properties of hollow fibers obtained under those conditions will be shown. Although the present invention will be understood more specifically by these numerous examples, the scope of the present invention is of course not limited to these examples. The water permeability, molecular weight cutoff, and bursting strength of the aromatic polysulfone resin hollow fiber membrane in this example were measured by the following methods. (1) Measurement of water permeability A module is made by sealing one end of a hollow fiber bundle whose outer and inner diameters have been measured in advance, and the other end is glued, with the glued side serving as the water injection side. The effective length is 2S, and the pressure difference between the inside and outside of the hollow fiber is /atmosphere, and the amount of permeation of distilled water at 2S°C (m
''/m'-day-atm). (2) Measurement of molecular weight fraction To measure the molecular weight fraction, connect both ends of a single hollow fiber whose outer diameter and inner diameter have been measured in advance to the water injection side and the drainage side, respectively. The effective length is 2Sα, the inlet pressure cuff is 2 kglcrl or less, the outlet pressure is 0.gkg/cJ or more, the average value of the inlet and outlet pressures is 10kg7ca, the linear velocity is 10yHy, and the various molecules dissolved in distilled water are Introduce an aqueous solution at 25°C from the water injection side, take 0.Sl of p water after 10 minutes, and calculate the cut rate from the amount of various molecules contained in it.When using dextran molecules to measure the fractionated molecular weight, When using globular proteins, use a concentration of 02S wt%.However, before injecting the globular proteins into the hollow fibers, add the molecular aqueous solution (5% by weight) into which the hollow fibers are injected. Measurement is carried out after pre-immersing in "C) for 2 hours to eliminate the influence of adsorption. (8) Measurement of burst strength: Bend both ends of the hollow fiber into a loop and fix. Apply the same air pressure from both ends at 2S''C, then 70 kg/r, t1
The pressure is increased at 4 nin. The pressure at which the hollow fiber bursts is defined as the bursting strength (kg/cJ). Example / Dimethylacetamide was selected as the solvent, tetraethylene glycol was selected as the additive, and polysulfone (hereinafter referred to as polysulfone) having a repeating unit represented by the following was added as a polymer to 7/:q:10% by weight, respectively.
A homogeneous solution was obtained by mixing at the following ratio. This polymer solution was extruded from an annular nozzle (33°//l11) for producing hollow fibers, and purified water was used as an internal and external coagulating liquid to coagulate the polymer solution from the inner and outer surfaces, thereby spinning a hollow porous membrane. At this time, the hollow fiber spinning conditions were as follows. Distance from the nozzle to the external coagulating liquid (hereinafter referred to as air travel distance) /,! icm. The properties of the obtained hollow fibers are as follows: inner diameter oqsws
, outer diameter/, 331ull, film thickness θJ rim, water permeability/2w? /m'day-atrrrr water temperature u5°c, bursting strength 3i ki/ca, dextran molecular weight/θ4,
'I×10'? The cut rate for
It showed a cut rate of S% or more. The cross-sectional structure of the obtained hollow fiber is the three-layer structure (AoB) of the present invention.
oCB1A1), and the inner and outer void layer ratio is /,
It was 3. The results of examining how the radius of the C1 pores of the obtained hollow fibers changes from the inner surface to the outer surface of the hollow fibers are shown in the curves...×... in Figure 7θ. Hollow fibers were obtained in the same manner as described above, except that dimethylacetamide, tetraethylene glycol, and polysulfone (Udel) were mixed in a weight ratio of 4I:9 to 7 to form a uniform polymer solution. C of the obtained hollow fiber
The results of investigating how the radius of one hole changes from the inner surface to the outer surface of the hollow fiber are shown in the curve -〇- in Figure 10.
Shown below. Example-~1. S' In the same manner as in Example//, various additives were added and hollow fiber spinning was carried out. Table 1 shows the additives added to the hollow fiber stock solution and the properties of the hollow fibers obtained. The cross-sectional structure of the obtained hollow fibers was all the S-layer structure of the present invention, and the ratio of inner and outer void layers was 10 to 13. (Left below) Using the same polymer solution as Comparative Example/Example/, the stock solution temperature was 25°.
After casting on a glass plate with a doctor's raid film thickness of yoopm at C, it was left to stand for 1 minute and solidified in water at 25''C.The properties of the obtained porous flat membrane were as follows:
Film thickness 300 pm, water permeability θ0/m7♂・day-
ATM, water temperature 2S℃, elastic modulus/ ,? / / kg7
cd, intensity b below OkiAtl. The structure of the obtained flat film was an ABC three-layer structure. In addition, flat films of various thicknesses were obtained by casting using the same polymer solution as above and using the same method as above. The relationship between the thickness and water permeability of the obtained flat membrane is shown in Figure 1S. The structure of these flat membranes is ABC 3
It had a layered structure. Comparative Example 3 Polysulfone lθt, N-methylpyrrolidone 909
Mix at 0"C to make a homogeneous solution. This poured solution was poured onto a glass plate using a doctor playdough to form a film with a thickness of 2!r.
It was cast in Opm and coagulated in water. The properties of the obtained porous flat membrane are as follows: film thickness/00 pm, water permeability 5 m"/ln'-day-a trrr water temperature ss"c), elastic modulus 23 g=33- , Strength/Okg/crl or less. The structure of the obtained flat film was an AB layer structure. Using this solution and using water as the internal coagulating liquid, the fibers are spun in the air from a hollow fiber spinning annular nozzle (, y3opm), and the polymer is coagulated from the inside of the hollow fiber with water.
Hollow fibers were spun using Son. The obtained hollow fiber membrane has an inner diameter of θ7SIE111 outer diameter/, 3S■, a membrane thickness of 03■, and a water permeability! m'/m"・day-atm・water temperature S℃, bursting strength/31g74+7, strength/θky/cJ,
The elastic modulus was kqA-. Furthermore, when the structure of the obtained hollow fiber membrane was examined using a scanning electron microscope, it was found that the hollow fiber did not have the five-layer structure unique to the present invention. Comparative Example q1S Polysulfone λθv1 as a polymer and dimethylacetamide ZaOf as a solvent were mixed to form a uniform solution. This solution was cast onto a glass plate at a stock solution temperature of 25''C using a Dr. Plaid to a film thickness of 3.0 ptx, and then allowed to stand for 1 minute to solidify in 2j''C water. The obtained porous flat membrane has a membrane thickness of 3θθμm1 and a water permeability of 0.0.
0! r m"/m'day-atrrr water temperature was 2.fC, and the membrane structure was an ABC structure. Using this solution, hollow fibers were spun under the same hollow fiber spinning conditions as in the true example. The fin properties of the obtained hollow fiber are: inner diameter θ7511I+, outer diameter i3s■, membrane thickness 03■, water permeability 00/m"/m'day-atnr water temperature, l"C,
Bursting strength k/ni9/crl1 strength k k'9/c, rl
, the elastic modulus isλ/I=yAJ. The structure of this hollow fiber was a five-layer structure of AoBOCBi Ai, but not the five-layer structure of the present invention. The inner and outer void layer ratio is 7.7
Met. Comparative Example B Using Udel as polysulfone, dimethylacetamide as a solvent and tetraethylene glycol as an additive were mixed at a ratio of 102 g/:9% by weight each to form a uniform solution. This solution was cast onto a glass plate using Dr. Plaid, and then allowed to stand for 7 minutes to solidify in water at 25°C. The resulting porous flat membrane had a thickness of 300 pm,
Water permeability S m'/+u'・day-atm・water temperature 25″
C1 elastic modulus, 2/, 4-kp/cr4, strength? kg7
F,! Met. The structure of the obtained flat film was an AB layer structure. Comparative Example 7 Oml of 50% by weight aqueous sodium nitrate solution was added to a mixed solvent of dimethylacetamide, 2620 ml and dimethyl sulfoxide/300 ml, and polysulfone (Udel) 7301 of Example was further added to form a homogeneous solution. A hollow fiber semipermeable membrane was obtained from this polymer solution in the same manner as in Example. Hollow fiber inner diameter o7s■, outer diameter /3
! wg, water permeability 10 m”/m'-day-atm, water temperature sfc, bursting strength/!; ky/crl, elastic modulus g2/9/
crl, intensity, 30 kgAd. Also, molecular weight 7
The cut rate for ×/θ4 dextran was 3%. The membrane structure is A. Although it had a five-layer structure of BocBi Ai, the inner and outer void layer ratio was /7, which was not the one of the present invention. Polymer solutions having the same composition as above were used to spin hollow fibers of various thicknesses, and the relationship between the membrane thickness and water permeability is shown by the curves in FIG. Example/6 Polysulfone (PS), dimethylacetamide (DMA
c) and tetraethylene glycol (TEG) at 20:? /:9wt% to form a uniform solution, and then extruded through nozzles with various hole diameters to spin hollow fibers with inner diameters θqswsm and outer diameters varying in thickness. Other conditions are the same as in Example. The obtained hollow fiber membranes all showed the S layer structure of the present invention,
The inner/outer void layer ratio was 10 to 13, showing excellent bursting strength, elastic modulus, and strength. The relationship between the membrane thickness and water permeability of these hollow fibers is shown in Figure 1 by 10-. In addition, polysulfone (Udel), dimethylacetamide, and tetraethylene glycol were added to /s:q, respectively. The relationship between the membrane thickness and water permeability of a hollow fiber obtained by spinning a homogeneous polymer solution mixed at a weight ratio of 2/S in the same manner as above is shown by the curve -Δ- in Figure 1/. Examples 77-21 Polysulfone (Udel) as polymer, tetraethylene glycol as additive, various solvents 20=7
A uniform spinning stock solution was prepared by mixing at a weight ratio of 7=9, and hollow fibers were spun. The spinning conditions were the same as in Example/. The cut rates of the obtained hollow fibers for various dextrans with different molecular weights were almost the same in Examples and 37-. Other properties are shown in Table 3. The structure of the hollow fiber is the five-layer structure of the present invention (AoBoCB, A, ')
The inner and outer void layer ratio was lO~/3. Table 3: Stock solution for membrane formation, polysulfone: Various solvents: Tetraethylene glycozole: RI/: 9 (heavy!"1 Hollow fiber inner and outer diameter 0.757i3 increase* Water permeability: m7m' da) + - atnr water temperature uj
'c Examples-1 to 23. Comparative example g DMAc as polysulfone solvent, TE as additive
Using G, the proportions of polysulfone and DMAc were varied to prepare membrane-forming stock solutions with different concentrations of polysulfone, and hollow fibers were spun in the same manner as in Example. The properties of the hollow fibers obtained are shown in Table G. Both membrane structures are A. It had a five-layer structure of BoCBi Ai, but only in comparative example g, the thickness of the C layer was as thin as 1 μm;
The layers were not uniform, and the void layer was disordered near where the void layer (B, layer, horse layer) was in contact with the C layer. In Examples 22 to 2S, the thickness of the C layer was 10
It is thicker than that of comparative example g at ~70 μm, and has a void layer,
In both layer C, a portion of the polymer had a uniform structure, and the ratio of inner and outer void layers was 10 to 4f. Air travel distance/Sm Hollow fiber inner and outer diameter 0.751111.1351+11
, Film thickness 03* Water permeability: m"/m'day-a
trrr water temperature 2! ;”C Examples 2A-3/, Comparative Example 9,
IO polysulfone (PS), dimethylacetamide (DMA
c) After mixing tetraethylene glycol (TEG) at a ratio of 20 N/:9 to make a homogeneous solution, the polymer solution was extruded through an annular nozzle, and purified water was used as the internal and external coagulation liquid to dissolve the polymer. A hollow porous membrane was spun by solidifying from the inside and outside surfaces. At this time, the air travel distance from the hollow fiber spinning nozzle to the external coagulation liquid was varied, and the properties of the obtained fibers were examined. The results are shown in Table 5. The membrane structure of the hollow fibers obtained was an S-layer structure (Ao
BoCBi Ai ), but in Comparative Example 9, the inner and outer void layer ratio was as large as 2.0, and the thickness of the C layer was 32 μm.
It was big. Comparative Example/The one with θ had a too long aerial travel distance, so the thread shape did not become hollow. Example 3
The thickness of the C layer obtained in Example 1 was within the range of S to qopm. -Jγ- Spinning stock solution, polysulfone: DMAc: TEG-,
20: 7/: 9 (weight t) Hollow fiber outer diameter/33; 1
ftI+, inner diameter oqsvx, film thickness 0.3Tm The thickness of the C layer of Comparative Example 9 was g-μm. *Water permeability: m'/iI+”-day-atnr Water temperature:
13'C Example 3+2.33 Using the same spinning stock solution as in Examples 21 to 3/, air travel path H11! The polymer was coagulated using methanol as i'cm % internal and external coagulation liquid. The obtained hollow fiber had an inner and outer diameter of θ75tm, /3S■, bursting strength, water permeability, elastic modulus, and strength of -l/-1 da O-. The membrane structure in each case was the five-layer structure of the present invention. Similarly, even when methanol was used as the internal coagulating liquid and water was used as the external coagulating liquid, good bursting strength, water permeability, elastic modulus, and strength were obtained. The membrane structure in each case was the five-layer structure of the present invention. Comparative Example // A homogeneous solution of polysulfone, dimethylacetamide, and tetraethylene glycol mixed in a ratio of uO:A5:15% by weight, respectively, was used as a stock solution for membrane formation, and this polymer was applied to hollow fibers of various sizes. AoBoCBiAi hollow fibers with a 5-layer structure of various film thicknesses are placed through an annular nozzle for production, coagulated on both sides (coagulated from the inside and outside) using water as the coagulation liquid, and are filled with air on the inside and water on the outside. By single-sided coagulation using Bi, using water on the inside and air on the outside A1Bof7), hollow fibers with a two-layer structure with various film thicknesses were formed, and their burst strength was measured.
Shown in Figure A. Example 3 Dimethylacetamide (DMAc) was added as a solvent.
4', 2- Polyether sulfone (hereinafter referred to as polyether sulfone VICTREX manufactured by ICI) having a repeating unit treated with tetraethylene glycol (TEG) is 6.5' = 75:, 20 (%), respectively. A homogeneous solution was obtained by mixing at the following ratio. This polymer solution was extruded from an annular nozzle (330 μm) for producing hollow fibers, and purified water was used as an internal and external coagulating liquid to coagulate the polymer solution from the inner and outer surfaces, thereby spinning a hollow porous membrane. At this time, the hollow fiber spinning conditions were as follows. Distance from the nozzle to the external coagulating liquid (hereinafter referred to as aerial travel distance)/Sα0 The properties of the obtained hollow fibers were as follows. Inner diameter θ7S, outer diameter /, 75m, film thickness Q, 3m+1
1. Water permeability / ,! ; m'/m'day-atm, water temperature u5''C1 bursting strength 33 kqAd, tensile modulus/
700 kg/cl, strength? Okg, /cJ,
The cut rates for dextran molecular weight 104 and dax104.7x104 are 0%, 65%, g, and 2%, respectively.
. The membrane structure was a five-layer structure according to the present invention, and the internal and external void ratio was /3. Hollow fiber spinning was carried out under the same conditions as in Example 3, with the addition of various additives. Table 6 shows the additives added to the hollow fiber stock solution and the properties of the obtained hollow fibers. The film structure was the S layer structure of the present invention, and the ratio of inner and outer void layers was /θ~15. (Left below) 173 = Zheng Yu Yu θ ) Niou To To Dou ka) To)
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Using the polymer solution of Q-l Comparative Example/Co Example 3q, the stock solution temperature was 2k°C.
After casting on a glass plate with a Dr. Plaid film thickness of t, too μm, the film was left to stand for 7 minutes.1. : Solidified in 25°C water. The properties of the obtained porous flat membrane were as follows. Film thickness 300/rm, water permeability 00θ/m'
/ln'day-atm/water temperature, the structure of the 25'Co flat film was an ABC structure. Comparative Example/3, il polyethersulfone/θf, N-methylpyrrolidone 901 were mixed at 30'C to form a uniform solution. This pouring liquid was cast onto a glass plate using a doctor playdough to a film thickness of 230 μm. The properties of the obtained porous flat membrane were as follows. Film thickness 10θμm 1 Water permeability 5
m"/m' day-atr+r water temperature, 2.5-℃,
Elastic modulus, 2: l/kg/cJ, strength/θkiA-F
The structure of the 0-square membrane was AB$$1 construction. Using this solution and using water as an internal coagulation liquid, spinning was carried out in the air from a hollow fiber spinning annular nozzle, the polymer was coagulated from the inside of the hollow fiber, and a hollow fiber was spun. The obtained hollow fiber membrane had an inner diameter of 07SII11 and an outer diameter of /3!
Km, film thickness θ3wr, water permeability km'/m'day・a
tnr water temperature u5°c, elasticity Ig J 231ai/r,
rl, bursting strength/OkgAtl or less. As a result of examination using a scanning electron microscope, this hollow fiber did not have the S layer structure unique to the present invention. Comparative example/! ;, /6 Polyether sulfone co of as a polymer and dimethylacetamide gov as a solvent were mixed to form a homogeneous solution. Using this solution, stock solution temperature 2. A Dr. Plaid film with a thickness of 00 μm was cast on a glass plate at S'°C, left for 7 minutes, and 2! ;”C was coagulated in water. The obtained porous flat membrane had a thickness of 300 pm and a water permeability of 0.
．． 00! ; m'/m'・day-atm H water temperature 5
'C. The flat membrane structure was an ABC structure. Using this solution, hollow fibers were spun under the same hollow fiber spinning conditions as in Example 3, and the properties of the obtained hollow fibers were as follows: inner diameter ols, outer diameter i3! ;1111. Film thickness 03w5
, water permeability 0.0/m'/+++'day-atm-
The water temperature was uA°c, and the bursting strength was 3θkq/ctl. The inner/outer void layer ratio was /7, and the structure was not a five-layer structure unique to the present invention. Example 9 Using the same polymer solution as in Example 3q, hollow fiber membranes with an inner diameter of 0.2 μm and different outer diameters and membrane thicknesses were spun using various annular nozzles. The relationship between water permeability and membrane thickness of this hollow fiber membrane is shown in FIG. The hollow fiber membrane structures were all five-layer structures according to the present invention, and the ratio of inner and outer void layers was /3. Comparative Example 17 A 30% aqueous sodium sulfate solution is added to 47qQml of dimethyl sulfoxide to form a homogeneous solution. This melt. Polyether sulfone with /2! rf was dissolved to form a polymer solution. The viscosity of this polymer solution is /900 centipoise (20″C). This polymer solution was extruded from an annular nozzle for producing hollow fibers (33(1)Pn') and coagulated from the inside and outside using water as a coagulating liquid. Hollow The inner and outer diameter of the thread is 07 left side, /3 left side, and the water permeability is 2 m.
''/m'-day-atm, water temperature, 2j'C, bursting strength/ll#A-. Also, the cut rate for dextran with molecular weights to, ooo was 70%.The hollow fiber membrane structure was 5. It had a layered structure, but the inner and outer void layer ratio was /7. Example 5 In the same manner as in Example 3, a hollow structure was formed using polyether sulfone as a polymer solution, tetraethylene glycol as an additive, and various solvents. The properties of the obtained hollow fibers are shown in Table 7. The hollow fiber membrane structures were all five-layer structures according to the present invention, and the ratio of inner and outer void layers was 10 to 3. Table: /S *Water permeability m'/ln"-day-atrrrWater temperature 25
°C example! ;t NJ-? , Comparative Example 7g Polyethersulfone DMAc% addition as solvent 119- TEG was used as agent, polyethersulfone and DM
By changing the proportion of Ac 2 , stock solutions for membrane formation with different concentrations of polyethersulfone were prepared, and hollow fibers were spun in the same manner as in Example 3q. The properties of the hollow fibers obtained are shown in Table g. The hollow fiber membrane structures of Examples 5A to S9 all show the five-layer structure of the present invention, and the inner and outer void layer ratios are 'zo-is'.
Met. In the comparative example/g hollow fiber, the thickness of the C layer is as thin as micrometers, and the C layer is not uniform, and the void layer is disordered near where the void layer (B, layer, 88 layers) contacts the C layer. Ta. Example 56
~S9 has a C layer thickness within the range of /θ ~ 70P, which is thicker than that of the comparative example /g, and has a void layer and a C layer.
The polymer portion of both layers had a uniform structure. (Left below) SO- *Water permeability m7m'-day-atm ・Water temperature u5'c
Examples 60-63. Comparative Example 19, polyether sulfone DMAc and TEG were each mixed with co-θnia/:? (%) to make a homogeneous solution, the polymer solution was extruded from an annular nozzle, and purified water was used as an internal and external coagulating liquid to coagulate the polymer from the inner and outer surfaces to spin a hollow porous membrane. At this time, the air travel distance from the hollow fiber spinning nozzle to the external coagulation liquid was varied, and the properties of the resulting fibers were examined. The results are shown in Table 1. The hollow fiber membrane structure of Examples 60 to 6s is 5 of the present invention.
It had a layered structure. On the other hand, the thicknesses of the six hollow fiber layers of Examples tO to A and S' were within the range of 0 μm. Table 9 Spinning dope polyether sulfone:DMAc:TEG=
, 2θ near/:? Hollow fiber outer diameter/J5m! 11, inner diameter 0
．． 75 shoulders, film thickness 03 haze *water permeability m”/m”-day-
atm-water temperature ss"C Example 66.67 Using the same spinning stock solution as in Example AO-45, the polymer was coagulated using an annular nozzle with an air travel distance of 1 j tan % using methanol as the internal and external coagulation liquid. The obtained hollow fiber had an inner and outer diameter of 0.15 m, 733 cycles, and good bursting strength, water permeability, elastic modulus, and strength.The membrane structure was the S-layer structure of the present invention, The inner/outer void layer ratio was 10~/S. Similarly, good bursting strength, water permeability, elastic modulus, and strength were obtained even when methanol was used as the internal coagulating liquid and water was used as the external coagulating liquid. The structure was the S-layer structure of the present invention, and the inner and outer void layer ratio was /, θ ~ /S. The figure shows A., BO% C% Bi X, respectively.
Each layer of Ai is shown. FIG. 2 is a scanning electron micrograph (at a magnification of 1:1) showing the entire cross section of the hollow fiber membrane of the present invention taken along a plane perpendicular to the fiber axis. FIG. 3 is a scanning electron micrograph (magnification: 330 times) showing a part of the cross section of the hollow fiber membrane shown in FIG. 2 in an enlarged manner. Figure 9 is a scanning electron micrograph showing an enlarged part of the Ai layer and Bi layer in the cross section of the hollow fiber membrane in Figure 2! iJ- magnification (1'100 times). Figure S shows the inner surface A of the cross section of the hollow fiber membrane in Figure 2. Scanning electron micrograph of the layer (magnification/41.000x). Figure 6 shows the outer surface A of the cross section of the hollow fiber membrane in Figure 2. Freeze-fractured cross-sectional scanning electron micrograph of the layer (magnification/'AOO
O times). Figure 7 is a scanning electron micrograph (magnification: 90x) of the circular inner part of the hollow fiber of the present invention, which was frozen and cut diagonally as shown.
It is. FIG. S is a scanning electron micrograph (1900x magnification) showing the intermediate layer (6 layers) in the cross section of the hollow fiber membrane in FIG. Figure 5 is a scanning electron micrograph (magnification: 1t6oo.x) of the intermediate layer (6 layers) in Figure S at a very high magnification. FIG. 7θ is a graph showing the relationship between the distance from the inner and outer surfaces of the hollow fiber and the radius of the existing C1 pores. Figure 1 is a graph showing the relationship between membrane thickness and water permeability of aromatic polysulfone hollow fibers of the present invention and comparative examples. FIG. 12 is a graph showing the relationship between the membrane thickness and water permeability of the aromatic polyethersulfone hollow fiber of the present invention. FIG. 13 is a graph showing the relationship between the thickness, water permeability, and bursting strength of the hollow fiber intermediate layer of the present invention. Figure 1 is a scanning electron micrograph of a cross section of a flat film with an ABC three-layer structure. FIG. 1S is a diagram showing the relationship between the film thickness and water permeability of the ABC membrane. The first diagram is A. FIG. 2 is a diagram showing the relationship between membrane thickness and bursting strength for a BoCBi Ai three-layer hollow fiber membrane and an AB or BA two-layer hollow fiber membrane. FIG. 77 is a perspective view schematically showing the C4 hole/unit of the intermediate layer structure of the hollow fiber of the present invention in comparison with the conventional one, (A) is the present invention, (B) is the conventional one. show something Patent applicant Asahi Kasei Industries Co., Ltd. Representative Patent Attorney Toru Hoshino 55- Figure 17 (A) (8) Procedural Amendment Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of Case Patent Application No. 12863 of 1982 2,
Title of the invention Polysulfone resin hollow fiber 3, Relationship to the case of the person making the amendment Patent applicant 1-2-6 Dojimahama, Kita-ku, Osaka-shi, Osaka (OO3) Asahi Kasei Corporation President Teru Miyazaki 4, representative Person: 3-7 Yotsuya, Shinjuku-ku, Tokyo, New Building 5B6, Subject of amendment Contents of amendment of procedural amendment submitted on February 15, 1988 ■ 1 Column 7 of drawing, Contents of amendment (as attached) Contents of amendment 1. The amendment shall be made in accordance with the full text correction statement attached to the specification. ■0 Drawings Figures 11, 12, 16, and 17 of the drawings will be corrected as shown in the attached sheet. Patent applicant Asahi Kasei Industries Co., Ltd. agent Patent attorney Toru Hoshino

Claims (6)

[Claims] (1), outer surface layer, outer void layer, intermediate layer, inner void layer,
A polysulfone resin hollow fiber membrane having a five-layer structure of an inner surface layer and having a thickness ratio of inner and outer void layers of 15 or less. (2) The polysulfone resin hollow fiber membrane according to claim 1, wherein the thickness of the intermediate layer is S μm or more and 70 μm or less. (3) The polysulfone-based tree mesosilum membrane according to claim 1, which has a total membrane thickness of 100 μm-too μm. (4) The polysulfone resin hollow fiber membrane according to claim 1rJi, wherein the membrane has a water permeability of 3 m7'&-day-atm or more. (5) The polysulfone resin hollow fiber membrane according to claim 1, wherein the polysulfone thread resin is aromatic polysulfone or aromatic polyethersulfone. (6), (Polymer concentration −/− containing ethylene glycol is /!; Overlapping and overlapping. A polar organic solvent solution of the risulfone yarn polymer is discharged from an annular nozzle in the form of a hollow fiber, and mixed with the solvent. However, a liquid that is not commonly understood as a polysulfone polymer is used as the inner and outer coagulating liquid, and the coagulating liquid is injected from the inside of the nozzle at an appropriate pressure, and after traveling a distance of more than O5 in the air, the external coagulating liquid is inserted into the inner and outer coagulating liquid. , the hollow fiber membrane thickness is approximately 100-6
1. A method for producing a polysulfone resin hollow fiber membrane, which comprises spinning the membrane to a thickness of 0.00 μm.