JPH06319967A - Porous hollow fiber membrane with continuous multiphase separating structure and production thereof - Google Patents

Abstract

PURPOSE:To provide a novel membranous fiber which maintains a structure wherein at least two kinds of polymer phases are tangled with one another and in which the polymers mutually make up for their disadvantages and the feature of each polymer is maintained. CONSTITUTION:At least two kinds of immiscible polymer solutions are mixed together and this mixture is made a multiphase blended solution having a phase changed structure or a similar blended form by a static mixer, etc., immediately before injection by a multiple annular nozzle for coagulation, whereby a hollow fiber membrane of the structure in which the polymer phases are continuously tangled with one another is obtained. By the combination of the polymers in this way, a membrane is provided which is changeable in thermal stability, hydrophilic property and the adsorbing performance for a biologically active substance such as protein and which is easily given a higher degree of function by the after-treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous hollow fiber membrane used for microfiltration, and more particularly, to use for a virus separation / removal / concentration test in the fields of medicine, medicine, microorganisms, biochemistry and the like. The present invention relates to a novel separation membrane which can be used not only for other industrial applications.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a porous hollow fiber membrane, a polymer constituting the membrane is blended with a second polymer, a third polymer or the like as a pore-forming agent, and the mixture is extruded from a multi-ring nozzle into a coagulation bath. A manufacturing method is employed which causes phase separation to form a desired porous membrane structure. In this case, the second polymer and below are soluble in a solvent having the same composition as the main polymer and are compatible with each other, and the membrane-constituting polymer remains after the hollow fiber is formed, and the second polymer and below are completely extracted to form a porous membrane. It

As a typical example of such an example, a method of blending a polysulfone or a polyethersulfone with a water-soluble polymer such as polyethylene glycol is proposed in JP-A-57-35906. That is, both polymers are dimethylacetamide, dimethylformamide,
Blended using a solvent selected from polar organic solvents such as dimethylsulfoxide, N-methyl-2-pyrrolidone or a mixed solvent thereof, the polymer solution is extruded through a multi-ring nozzle, and polysulfone or polyether sulfone is a non-solvent thereof. Is solidified in an aqueous coagulation bath and microphase-separated to produce hollow fibers having a predetermined porous membrane structure. At this time, polyethyleneglycol and the like are water-soluble, and finally completely extracted into water. These second and lower polymers dominate the film structure during phase separation, and once solidified and solidified are no longer necessary. Also, these polymers are not capable of forming fibers by themselves.

Further, JP-A-58-104940 proposes that polyvinylpyrrolidone or the like is selected and added as the water-soluble polymer, and a small amount remains after elution with water to impart hydrophilicity. When even a part of the water-soluble polymer is left, a post-treatment for insolubilizing the water-soluble polymer is necessary, and the technique is disclosed in JP-A-62-38205, 63-97205 and the like.

As a method of blending different polymers, for example, as described in JP-A-57-50507, polysulfone may be mixed with a cellulose derivative, or JP-A-57-50 may be used.
The acrylonitrile-based polymer described in No. 506 is mixed, or as a polymer of the same system, JP-A-56-86941
There are many examples such as mixing the polysulfone and the polyether sulfone described in 1) or mixing the same polymer having different polymerization degrees. The purpose is to increase strength, improve spinnability, control pore size, improve flux, and the like.

Further, in order to combine the features of each other, it is generally difficult to select a solvent and a non-solvent as a coagulant in the production of a porous hollow fiber membrane formed by blending different polymers. Even if a solvent and a non-solvent are found, if there is no compatibility between the polymers, the miscibility between the solutions is poor and the stability of the stock solution is poor, making spinning difficult. For this reason, such a combination of different polymers is usually not available for the first time only in the case of a compatible system in which the composition ratio and the temperature are less restricted, or a semi-compatible system having a certain composition ratio and a single layer region in which a certain temperature range is compatible. It is possible to manufacture a porous hollow fiber membrane by the spinning method described above. On the other hand, almost no attempts have been made to produce hollow fiber membranes by blending incompatible polymers that do not dissolve each other in most regions.

[0007] Generally, in order to improve the performance by combining different kinds of polymers, a method of forming a polymer alloy through a melt system is well known. When polymers that are incompatible with each other are melted and mechanically mixed, the mixture generally consists of an emulsion state, the so-called continuous phase of sea and an island structure of dispersed phase. Coalescence and coarsening eventually lead to the respective polymer phases and separation. Such separation is a phenomenon common to both the melt system and the solution system, and since the viscosity is generally lower in the solution system, this phenomenon occurs more rapidly and spinning of the hollow fiber becomes very difficult, and it has been hardly studied.

[0008]

However, the porous hollow fiber membranes obtained by blending polymers which are capable of forming fibers themselves but are incompatible with each other so as to exert their respective characteristics have a wide range of characteristics. It is considered to be attractive because it can be expected that, for example, polyvinylidene fluoride, polysulfone, polyether sulfone, polyamide imide, polyketone, polyimide which are hydrophobic polymers, and ethylene-vinyl alcohol copolymerization which is a hydrophilic polymer. Combinations of polymers such as coalesce, polyvinyl alcohol and acetalized products thereof are considered.

In particular, in the case of producing a porous hollow fiber membrane, a production method using a mixed solution of such different polymers as a starting material is an issue. For example, for the above polymer examples, a production method using a polar solvent such as dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone becomes a problem.

More specifically, referring to the problem by way of example, a biphasic continuous porous hollow of a hydrophobic polyvinylidene fluoride and a hydrophilic ethylene-vinyl alcohol copolymer as a combination of incompatible polymers. If a fiber membrane is available, it can be said that it is an excellent product, and it can be said that it is an attractive subject. That is, polyvinylidene fluoride is one of hydrophobic polymers, is excellent in chemical resistance, heat resistance, and film formation, is strong, and is widely used as a film material. However, when used, it has poor water wettability due to its hydrophobicity, and in order to use it in an aqueous system, a laborious process such as substituting with water after pretreatment with alcohol is essential. Alternatively, there are drawbacks such as large non-covalent adsorption of proteins. In order to improve these, various methods of hydrophilic treatment in the manufacturing process have been proposed.

On the other hand, the ethylene-vinyl alcohol copolymer is hydrophilic and has good biocompatibility, and is used in large amounts especially in artificial kidneys. There is also an example in which it is used by being bonded to the surface of a hydrophobic film by post-treatment. For example, JP-A-61
It has been proposed in -271003 that this polymer be bound to the surface of a hydrophobic membrane by a post-treatment to make it hydrophilic and reduce protein adsorption. However, the ethylene-vinyl alcohol copolymer alone has a large water absorbency, becomes a hydrogel, and the film strength when wet is significantly reduced. If the water-absorbed film is dried as it is, it will shrink and the film performance will change, making reuse impossible. There is also a drawback that it cannot be used above 50 ° C.

In other words, it is an object of the present invention to combine polymers having their respective characteristics, to utilize the characteristics of both, and to exhibit a combination of dissimilar polymers that complements each other by a continuous multiphase structure. is there.

[0013]

It is well known that, when mechanically mixing an incompatible system, an emulsion is formed and a sea-island structure is formed. On the other hand, when the polymers form a semi-compatible system, they are mixed and homogenized in the region where they are once in a one-phase state, as described in detail in “Polymer Alloy” (Kyoritsu Shuppan, 1988 first edition). When phase separation is performed by changing the conditions of the phase region, for example, by changing the temperature of the system, a characteristic higher-order structure different from sea islands is formed. This is generally referred to as spinodal decomposition, and the separated phases are continuously formed together to form a phase structure in which they are regularly entangled with each other with a structural period. That is, it is known that a state called a modulation structure having a constant structure period can be maintained. In addition, for a combination of incompatible polymers, a system containing concentrated polymer by gradually evaporating the solvent from a homogeneous system using a solvent plunges into the two-phase region and undergoes phase decomposition in a spinodal decomposition mode to form a modulated structure. It is also known to configure. Based on the above technical background, the inventors have earnestly studied to produce a porous hollow fiber membrane having different polymer phases continuously present.

As a result, a modulation structure is imparted to a solution mixture obtained by dissolving polymers having a fiber-forming ability but incompatible with each other without going through the above-mentioned one-phase state or a homogeneous system, and solidified from multiple annular nozzles. The present invention has been completed by discovering a porous hollow fiber membrane having a continuous multiphase separation structure which is discharged and solidified in a bath and a method for producing the same, and will be described in detail below.

The number of polymers and copolymers having spinnability is so numerous that they are incompatible, and the number of combinations of those polymers which are incompatible with each other is enormous, and the compatibility cannot be expected as the kinds of polymers increase. . If you try to dissolve such a polymer in a solvent, there are a considerable number of pure solvents and mixed solvents, but even if a solution of each polymer can be prepared but the polymers are not compatible with each other, the mixture of these solutions is a homogeneous system. It is normal not to form.

However, it has been found that vigorous stirring of such a mixture may achieve a different modulation structure or modulation structure-like situation than conventional emulsions. Furthermore, since the hollow fiber structure is maintained even if only one of the constituent polymers of the porous hollow fiber membrane obtained by discharging and solidifying into the spinning bath while maintaining this modulation structure is dissolved, the respective polymer is maintained. It has been found that the phases have a structure in which the phases are continuously entangled with each other, and the object of providing a porous hollow fiber membrane having a continuous multiphase separation structure and a method for producing the same has been achieved.

Here, when the modulated structure is typically achieved, the achievement is usually achieved because the emulsion has a substantially spherical island portion in the sea portion by high-speed photography of the mixed solution being stirred. You can check. On the other hand, the term “modulated structure similarity” means that in the state where the mixed solution is stirred, the presence of non-spherical shapes in each solution cannot be confirmed, but the final hollow fiber is a porous hollow fiber produced as described in the structural analysis of the example. Since the remaining polymer retains the fibrous structure even after dissolving each one component of the above polymer, it is defined as such a mixed solution under stirring, and substantially has the intended continuous multilayer separation structure. From the viewpoint of providing a high quality hollow fiber membrane, it will be collectively referred to as a modulation structure hereinafter.

While the conventional modulation structure is achieved by once passing through a compatible system or a homogeneous solution system to a spinodal decomposition step, the present invention creates a situation from the beginning through a spinodal decomposition step, which is extremely unstable. In order to obtain such a state by stirring, the type of polymer, the combination of polymers, the solvent that dissolves this, the mixed solvent, the mixed solvent, It is essential to select the solution concentration, the solution temperature, etc., and a general selection index has not been known yet. However, the point is that it is possible to realize a state in which the solution phases are entangled with each other in a strongly stirred state, and in the above-mentioned solution system, polyvinyl chloride and acrylonitrile-dissolved in tetrahydrofuran which are already known in tetrahydrofuran are known. Such a state can be easily determined by referring to the fact that the solution of the butadiene copolymer forms a modulation structure by spinodal decomposition in the process of evaporating tetrahydrofuran.

By the way, in the above-mentioned stirring, it is a very important point from the viewpoint of obtaining a uniform fiber structure or maintaining sufficient strength, etc., so as not to entrain the gas component in the mixed solution system. . In particular, in the case of the present application, it is essential that the solutions are easily separated and vigorously stirred so that the solutions maintain the sea-sea condition, but as a result, the gas components are easily involved. For this reason, stirring must be devised so that gas entrainment can be avoided.For example, prepare a solution for each polymer, supply these solutions to a static mixer after degassing, and maintain a sea-sea mixing state until just before the nozzle. It is useful to maintain the temperature at a constant value and discharge from multiple annular nozzles to solidify and solidify. Here, the static mixer has a hollow cylindrical housing 1 and a mixing unit 2 as shown in FIG.
The mixing unit 2 has a plurality of elements 3 connected in the longitudinal direction, and one element is twisted in the circumferential direction, for example, 180 degrees as the plate body advances in the longitudinal direction. It has such a shape.
The twisting directions of the adjacent elements are opposite to each other, and the connecting portions 4 of the elements are connected with the plate surfaces twisted by 90 degrees. The fluid is divided into two for each element, and the total number of divisions N is

## EQU1 ## N = 2 ⁿ (n is the number of elements), and the fluids are mixed. Further, the fluid is rearranged within each cross section and is homogenized by changing the rotation direction for each element, which is a suitable stirring means in the present application. Further, in supplying the solutions, it is preferable to install a supply means, that is, a pump or the like immediately after each solution and immediately before the static mixer, and if necessary, further supply means may be provided immediately after the static mixer.

Alternatively, a method in which a required number of polymers and a required amount of a solvent having a constant composition are intensively stirred all at once with a stirring blade under vacuum to maintain the modulation structure and spinning as in the above is also useful. While performing line mixing between the stirring tank and the nozzle with a static mixer, the same operation can be performed by a supply means installed before or after such a mixer or before or after such a mixer. However, when operating under such a vacuum, it is necessary to position the mixed solution tank so that it has a head above atmospheric pressure in order to avoid backflow of air from the nozzle side. is there.

Further, it is preferable to adjust the temperature or to add the same or different solvent to the stirring step in order to more easily bring the modulated structure to the modulated structure by stirring. The determination is made clear by observing the agitated state of the mixed solution before spinning as described above or by structural analysis after spinning. It is difficult to determine the stirring conditions such as the number of rotations and the number of elements, etc., which are difficult to determine for the system of the components of the mixed solution, and the shape and number of stirring tanks and lines, stirring blades and elements, etc. These can be determined based on the above judgment criteria by trial and error. The solvent is usually preferably a polar solvent as described above, but in dissolving the polymer, it may be a common solvent or a different solvent, and a pure solvent or a mixed solvent may form a modulated structure so long as the desired porous hollow fiber membrane is obtained. A solvent suitable for a combination of polymers may be selected from many combinations. However, considering the recovery system, it is preferable to use a pure solvent in common.

The multi-annular nozzle is an indispensable facility for producing hollow fibers. Water and other solvents are supplied to the central nozzle, and the hollow fibers are solidified and solidified from the inside at the nozzle outlet, and are located outside the annular nozzle. In order to coagulate and solidify the hollow fiber from the outside by supplying the polymer solution mixed fluid having the above-mentioned modulation structure to the channel of the above and contacting the coagulation bath through the dry zone after discharge from the nozzle, or directly contacting the coagulation bath by discharge contact. Used. As for the size of these nozzles, of course, those having dimensions as necessary are selected and used in order to determine the inner and outer diameters of the hollow fibers. In addition, in order to improve the ejection property from the nozzle, a surfactant may be appropriately added to the solution.

The fine pores of the fibers are formed by microphase separation by desolvation, but the nozzle discharge conditions of the polymer-containing mixed solution, that is, the nozzle linear velocity, nozzle temperature, dry zone temperature / humidity, coagulation bath temperature, coagulation Type of bath liquid,
The number of pores and pore diameter can be selected by selecting conditions such as fiber winding speed, polymer combination, selected modulation structure, solvent type, and polymer concentration, and the pore diameter is 0.01 to 1.0 μm.
You can choose in the range of m. Thus, the porous hollow fiber membrane having the desired continuous multiphase separation structure is produced by applying the above method.

Also, at least one of such constituent polymers
When a functional group is bonded to the species, for example, the above-mentioned ethylene-
In the case where a vinyl alcohol copolymer is used as a constituent element, once a porous hollow fiber membrane having a continuous multiphase separation structure is produced, a higher-order chemical modification can be performed by utilizing the chemical reaction capable of the functional group. It is possible and the use of the hollow fiber can be greatly expanded.

[0025]

[Function] A polymer which is difficult to form a homogeneous system and which is not compatible with each other is strongly stirred by a static mixer or the like to achieve a modulation structure or a structure similar to that of a normal emulsion and maintain this modulation structure. As it is, the mixed solvent is discharged and solidified in the spinning bath together with the coagulating liquid supplied to the multi-annular nozzle to form the porous membrane hollow fiber having the continuous multiphase separation structure.

[0026]

【Example】

Example 1 Production of Porous Hollow Fiber Membrane Having Continuous Multiphase Separation Structure Composed of Polyvinylidene Fluoride and Ethylene-Vinyl Alcohol Copolymer Polyvinylidene fluoride and ethylene-vinyl alcohol copolymer are simultaneously added to dimethylacetamide which is a common solvent. When added, polyvinylidene fluoride was easily dissolved, but due to the difference in the dissolution rate, the ethylene-vinyl alcohol copolymer was difficult to dissolve, and each was dissolved separately. That is, polyvinylidene fluoride (Kureha Chemical, trade name Kureha KF # 1000)
20 parts by weight, polyoxyethylene sorbitan monooleate as a surfactant (Kao Atlas, trade name Tween 8
0) 0.5 parts by weight As a coloring inhibitor, 1 part by weight of paratoluenesulfonic acid was dissolved in 78.5 parts by weight of dimethylacetamide at 60 ° C. with stirring to prepare a spinning solution A. on the other hand,
20 parts by weight of an ethylene-vinyl alcohol copolymer (Kuraray, trade name Eval EP-F101: 32 mol% of ethylene) and 0.5 part by weight of a surfactant (Tween 80) in 79.5 parts by weight of dimethylacetamide at 120 ° C.
The solution was stirred and dissolved with to prepare a spinning solution B.

A Noritake static mixer (21 elements) and an annular slit nozzle having an outer diameter of 1.0 mm, an inner diameter of 0.5 mm and an inlet diameter of 0.25 mm are connected to each other, and the stock solution A and the stock solution B are directly placed in the static mixer. While injecting a fixed amount, the mixture was discharged from the annular nozzle while changing the mixing ratio of the stock solution A and the stock solution B, and at the same time, an aqueous solution of 30% by weight of dimethylacetamide was injected as an injection solution from the central hole, and after passing through the dry zone 100 mm, the coagulation bath It was introduced into water, 40 ° C., and coagulated and washed with water, and wound up and dried at 30 m / min. During this period, a porous hollow fiber membrane having a clean circular cross section without producing yarn breakage under any of the conditions could be produced. Further, even at a spinning speed of 45 m / min, a porous hollow fiber membrane could be produced in the same manner as in the above experiment, which was far superior to the productivity with the ethylene-vinyl alcohol copolymer alone. Table 1 shows the production conditions / conditions and performance of the obtained hollow fiber.

[0028]

[Table 1]

Note * 1: BP (Bubble Point) Twenty manufactured 200 mm long hollow fibers are bundled in a U shape, and a portion 10 mm below the opening is adhesively bound into a rubber plug of 20 mm in length with urethane to form a rubber plug. 3 mm was cut, fitted into a steel pipe, the fiber part was immersed in water for 1 hour, deaerated at 50 mmHg to remove air bubbles, and then air pressure was gradually applied through a valve attached to the steel pipe side to generate air bubbles first. Air pressure P
Read. Calculate the bubble point by subtracting the atmospheric pressure and the water head. Note * 2: Protein adsorption amount 20 hollow fibers produced were bundled in a U-shape with a length of 50 mm,
The module was housed in a polycarbonate housing having an inner diameter of 6 mm and an outer diameter of 10 mm, and the open end was potted with a polyurethane resin to prepare a module. The obtained module was sterilized with ethylene oxide gas and then dissolved in a PBS buffer solution (pH = 7.3, manufactured by Nissui Pharmaceutical Co., Ltd.) 0.02.
5% bovine serum albumin (Bovine Se manufactured by Sigma)
rumAlbumin) protein solution (100 ml) at room temperature under a pressure of 0.5 kg / cm2 from the outside to the inside of the hollow fiber toward the open end, and measure the amount of protein in the recovered solution by measuring the absorbance at a wavelength of 280 nm. The amount of protein adsorbed on the hollow fibers was calculated by quantification and subtraction.

From Table 1, it can be seen that the physical properties and performances vary depending on the composition. For example, the bubble point, which is said to be in parallel with the maximum pore size, shows a gradual correspondence corresponding to the change in the composition of the hollow fiber, whereas the relationship between the amount of polyvinylidene fluoride and the amount of adsorbed protein is specific. In Experiment No. 3, the amount of protein adsorbed on the porous hollow fiber membrane containing only polyvinylidene fluoride was 1/4 to 1/2, and the presence of the ethylene-vinyl alcohol copolymer had a strong influence. Although it is still recognized, it shows a feature that does not change so much after that. Although the reason has not been clarified, it can be said that it shows one of the characteristics of the porous hollow fiber membrane having a continuous multiphase separation structure produced by the method of the present invention. It is considered that the following structural analysis operation will contribute to this idea.

That is, the hollow fiber of Experiment No. 1 was replaced with ethylene-
Vinyl alcohol copolymer is soluble and polyvinylidene fluoride is insoluble. 50:50 with a solution of isopanol and water.
When it was treated at 0 ° C., the weight loss was about 40%, and a hollow fiber-like shape having a phase structure of polyvinylidene fluoride alone remained.

Further, the same hollow fiber was treated with an aqueous solution of 2 parts by weight of glutaraldehyde, 3 parts by weight of sulfuric acid and 95 parts by weight of water at a temperature of 60 ° C. to carry out a cross-linking reaction of the ethylene-vinyl alcohol copolymer, and then this. Dimethylacetamide 60 ° C
Processed in. The weight loss was about 60%, and the hollow fiber shape based on the phase structure of the ethylene-vinyl alcohol polymer alone remained.

Phase No. 1 of Experiment No. 1, phase structure of polyvinylidene fluoride alone after elution of ethylene-vinyl alcohol copolymer, and phase structure of crosslinked reaction product of ethylene-vinyl alcohol copolymer by elution of polyvinylidene fluoride Electron microscope The photographs are shown in FIGS. 1, 2 and 3, respectively. From this, it can be judged that the polyvinylidene fluoride and the ethylene-vinyl alcohol copolymer each had a continuous phase structure and formed a structure in which both were entangled with each other. By the way, when the hollow fiber production was performed in the same manner as in Experiment No. 1 except that the static mixer element was changed to 6, and the above-described structural analysis operation was performed, polyvinylidene fluoride had a continuous phase structure. , Ethylene-vinyl alkote copolymer is a structure that is extremely fragile and cannot be said to be in a nearly continuous state, and the ethylene-vinyl alcohol copolymer is considered to have formed an island structure with respect to the sea structure of polyvinylidene fluoride. It was Further, as is clear from the above operation, it is shown that the hydroxyl groups of the ethylene-vinyl alcohol copolymer constituting the structural unit of the initially produced porous hollow fiber membrane can advance the chemical reaction with the aldehyde group, It can be said that the functional group of the hollow fiber membrane enables subsequent high-order chemical modification.

These porous hollow fiber membranes showed marked tensile strength, unlike those produced from ethylene-vinyl alcohol copolymer alone. It seems that polyvinylidene fluoride forms a structural unit, but the interaction between both polymers increases during the formation of the modulation structure formed through the mixed solution state, and simply polyvinylidene fluoride exists as a continuous structure. It is considered that the strength improving effect was exhibited not only by doing so.

Example 2 20 parts by weight of transparent polyvinylidene fluoride defoamed in the same manner as in Example 1 and ethylene-vinyl alcohol copolymer 20
A dimethylacetamide solution containing each part by weight was stirred in a weight ratio of 3 to 2 without stirring to obtain a mixed stock solution. This stock solution is a cloudy opaque mixed solution, and gradually forms emulsion particles when stirring is stopped. The phases were separated. Immediately after stirring, the opaque mixed liquid was discharged from the center of the annular nozzle at a feed rate of 3 g / min from the center of 10 g / min through a static mixer in the same manner as in Example 1, and after passing through a dry zone of 100 mm, 30% by weight of dimethylacetamide.
Is solidified with a coagulating liquid consisting of an aqueous solution of and washed with water to 30 m / m
It was rolled up in. The spinning condition was extremely good, and as in Example 1, a porous hollow fiber membrane having a structure in which both polymers were continuously entangled with each other was obtained. The hydrophilicity was good, and no change in the membrane performance was observed even after treatment with hot water at 90 ° C., and repeated use was possible.

Comparative Example 1 Similar to Example 2, a dimethylacetamide mixed solution containing 12% by weight of polyvinylidene fluoride and 8% by weight of ethylene-vinyl alcohol was spun by a usual method without passing through a static mixer. Initially, spinning was possible. However, many hollow particles were generated on the surface of the yarn over time, and a uniform hollow fiber could not be obtained. Thread breakage occurred frequently over time, making spinning impossible. This is because the separation of the two phases proceeded and a partial non-uniform coagulated polymer was generated due to the difference in the dissolution rate of both polymers, which showed a non-uniform phase separation phenomenon.

[0037]

As described above, in the method for producing a multi-phase continuous porous hollow fiber membrane of the present invention, only required kinds of polymers are selected on the basis of basic physical properties and characteristics, and pure solvents or mixed solvents thereof are selected respectively or It became possible to manufacture a multi-phase continuous porous hollow fiber membrane through a spinning process in which the compound was dissolved all at once, and a modulation structure was formed by a strong stirring means such as a static mixer and a spinning process was performed. (It shows the effect of omitting the manufacturing process of forming a modulation structure through a conventional homogeneous solution system and a spinodal decomposition process.)

Further, in the multi-phase continuous porous thin film hollow fiber produced in this manner, the raw material polymer retains its fiber-forming ability as shown in the above-mentioned Examples. The whole multi-phase continuous porous thin film hollow fiber produced by having the conventional properties and being able to complement the properties / performances that one polymer cannot have with the other polymer, and such properties are present continuously in the polymer. The effect that extends to appeared.

Furthermore, when at least one of the polymers has a functional group, it can be modified by a chemical reaction utilizing the functional group, so that the effect of having a use as a raw material of a higher-order chemically modified porous hollow fiber membrane becomes clear. It was

[Brief description of drawings]

FIG. 1 is a hollow fiber produced in Example 1 of the present invention.

[Fig. 2] Same as above, except that the fiber was isopropanol / water = 50/50.
Hollow fiber dissolved in

FIG. 3 is a hollow fiber obtained by crosslinking the hollow fiber produced in Example 1 with glutaraldehyde and then subjecting it to dissolution treatment with dimethylacetamide.

FIG. 4 is a diagram showing a structure of a static mixer.

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[Procedure amendment]

[Submission date] November 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

1] Shape of hollow fiber produced in Example 1 of the present invention
Is a photograph showing .

[Fig. 2] Same as above, except that the fiber was isopropanol / water = 50/50.
2 is a photograph showing the shape of the hollow fiber that has been subjected to the dissolution treatment in Step 1.

FIG. 3 is a photograph showing the shape of hollow fibers produced by crosslinking the hollow fibers produced in Example 1 with glutaraldehyde and then dissolving with dimethylacetamide.

FIG. 4 is a diagram showing a structure of a static mixer.

Claims (4)

[Claims] 1. A polymer-containing liquid is discharged from an annular nozzle,
In the method for producing a porous hollow fiber membrane to be solidified, a modulation structure is imparted by stirring to a solution mixture obtained by dissolving two or more polymers having a fiber-forming ability but not compatible with each other,
A porous hollow fiber membrane having a continuous multiphase separation structure formed by discharging and solidifying from a multiple annular nozzle into a coagulation bath. 2. A polymer-containing liquid is discharged from an annular nozzle,
In the method of producing a porous hollow fiber membrane for coagulation, a solution mixture prepared by dissolving two or more types of polymers capable of forming a fiber but having incompatibility with each other is provided with a modulation structure by agitation to be discharged from a multiple annular nozzle into a coagulation bath and solidified. And a method for producing a porous hollow fiber membrane having a continuous multiphase separation structure. 3. The porous hollow fiber membrane according to claim 1, which is capable of higher-order chemical modification based on at least one polymer having a functional group. 4. The method for producing a porous hollow fiber membrane according to claim 2, wherein at least one of the polymers has a functional group and is capable of high-order chemical modification.