JPS6259611B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is applicable to concentration of solutions such as precision filtration and ultrafiltration.
This invention relates to a new separation membrane suitable for substance separation.

In recent years, separation technology using membranes has attracted attention in application fields such as wastewater treatment, the food industry, and the medical field, and further development is expected.

This membrane separation technology uses
Techniques such as precision dialysis, ultraviolet dialysis, and dialysis are used. It goes without saying that the performance required of a membrane differs depending on the purpose of separation, but the commonly required performance is a high permeation rate for aqueous media, and a high permeation rate for suspended, dispersed, or dissolved substances. Examples include excellent exclusion ability and mechanical and chemical strength.

The purpose of the present invention is to satisfy the above-mentioned performances to a certain degree of practicality, and to produce a width suitable for the purpose in the same manufacturing process by using two types of methyl methacrylate copolymers and adjusting the blend and additives. The purpose of the present invention is to provide a separation membrane (precision membrane, ultrafiltration membrane) having a wide permeability.

In particular, the polymethyl methacrylate-based ionic crosslinked separation membrane of the present invention has good compatibility with blood, so it can be used in blood purification systems such as plasma separation therapy, artificial livers, and artificial kidneys when it comes into contact with blood, plasma, and serum. It provides suitable membranes. Some specific examples include plasma separation (separation of formed components in blood and plasma), treatment of immune diseases by separating high molecular weight proteins such as immune complexes from low molecular weight proteins such as albumin (rheumatism, SIE, glomerulonephritis, etc.), and purification of serum for culture (removal of cell growth-inhibiting components and degenerative components, etc.).

In the case of plasma separation, it is desirable that plasma proteins such as albumin and globulin pass through at a high permeability, but that red blood cells, white blood cells, and platelets do not pass through at all, and that the plasma separation rate is high without causing hemolysis or coagulation. .

Plasma separation rate is affected by blood hematocrit value, protein concentration, blood flow rate, overpressure, etc., but considering clinical use, the blood flow rate is 100ml/min.
In this case, approximately 30 to 60 ml/min. is required. For this purpose, the permeability of albumin should be at least 90%, preferably substantially complete, and the water permeation rate (water UFR, UFRS) measured in water should be between 2 and 60/
hr・m ²・mmHg preferably 4-30/hr・m ²・
Performance around mmHg is required. In another expression
A membrane with a pore diameter in the vicinity of 0.1 to 0.8 microns and a high porosity is desired.

In addition, in cases such as treatment of immune diseases or purification of serum for culture, the size of proteins to be separated differs depending on the type of disease or culture purpose, but in general, the permeability of albumin is is 30～
100%, preferably 70-100%, and the water permeability (water UFR) measured in water is 0.1-20/hr・^m2・
Performance in mmHg, preferably around 1 to 10/hr·m ² ·mmHg is required. In other words, a membrane with a cell diameter of around 0.01 to 0.2 microns and a high porosity is desired.

In other words, the present invention provides a membrane that satisfies these required permeation performance, that is, a membrane with an albumin permeability of 30.
% or more, and the water permeation rate is 0.1 to 60/hr・
The present invention provides a method for producing a polymethyl methacrylate-based ionic crosslinked separation membrane having a temperature of m ² ·mmHg.

The water permeability (UFR of water) and albumin permeability are measured using conventional methods; water permeability is measured using distilled water, and albumin permeability is measured using bovine albumin (Fr.V) (e.g., Seikagaku Corporation, Sigma). ) to 0.2
It is carried out using a solution dissolved in distilled water to a concentration of g/dl.

If the separation membrane is a flat membrane, use a normal stirring cell (for example, Amicon Standard Cell Model 52), and if it is a hollow fiber, use a module with an effective length of 5 cm or more made by bundling 10 or more fibers. at °C
Stirring is performed in the stirring cell under a pressure of 50 mmHg, and the linear velocity at the inlet of the hollow fiber is set to 5 cm/sec. or more, and the calculation is made from the liquid for 30 minutes between 30 and 60 minutes, when the liquid volume becomes stable.

Transmittance = (Albumin concentration in permeate solution) / (Albumin concentration in stock solution) × 100 (%) In the present invention, basically two types of polymers are used as membrane materials, namely, polymerizable monomers having sulfonic acid groups. A methyl methacrylate copolymer containing 0.5 to 10 mol% of methyl methacrylate, and a polymerizable monomer having a quaternary nitrogen group.
Using a methyl methacrylate copolymer containing 0.5 to 10 mol%, adjust the copolymerization rate, copolymer mixing ratio, glycerin or formamide concentration in the solvent, and material polymer concentration in the membrane forming solution (filtering stock solution). Through the same manufacturing process, we can provide various separation membranes suitable for various uses. One of the two types of copolymers used here as a membrane material is a polyanion having a sulfonic acid group, and the other is a polycation having a quaternary nitrogen group. The separation membrane is an ionically crosslinked polyion complex membrane. Therefore, in combination with the properties of polymethyl methacrylate, which has high membrane strength and excellent blood compatibility, it can be said that it is particularly suitable as a separation membrane for medical applications that come into contact with blood components.

Examples of polymerizable monomers having a sulfonic acid group to be copolymerized with methyl methacrylate include P-styrenesulfonic acid, allylsulfonic acid, methacrylsulfonic acid, 3-methacryloxypropanesulfonic acid, vinylsulfonic acid, -Acryloxypropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and their sodium salts, potassium salts, ammonium salts, and pyridine salts. Among these, alkali metal salts are preferably used. Furthermore, sodium p-styrenesulfonate is particularly preferably used. These monomers are used as one of the membrane material components by copolymerizing with methyl methacrylate, but the upper limit of the content of the copolymer component is within the range in which the copolymer does not dissolve in water, and is usually 0.5 It is used in an amount of ~10 mol%, preferably 1-5 mol%.

The copolymer to be mixed as another membrane material component is prepared by copolymerizing a polymerizable monomer having a quaternary nitrogen group with methyl methacrylate. The upper limit of the content of the monomer having the above is also within the range in which the copolymer does not dissolve in water, and is usually 0.5 to 10 mol%, preferably 1 to 5 mol%.

A few examples of these polymerizable monomers having a quaternary nitrogen group include 2-methacryloyloxyethyltrimethylammonium chloride, 2-
Methacryloyloxyethyltriethylammonium chloride, dimethyl (2-methacryloyloxyethyl)phenylammonium chloride, 2-acryloyloxyethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride,
These include vinylbenzyltrimethylammonium chloride, methyl (2-methyl-5-vinyl)pyridinium chloride, and it goes without saying that bromide, iodide, sulfate, sulfonate, etc. can be used instead of chloride.

Furthermore, if necessary, the methyl methacrylate copolymer containing a polymerizable monomer having a quaternary nitrogen group can be prepared by copolymerizing the polymer with a polymerizable monomer having a tertiary nitrogen group. It can also be prepared by quaternizing by a known method using a known quaternizing agent in the reaction method. For example, methyl methacrylate and dimethylaminoethyl methacrylate are copolymerized and converted into a quaternary ammonium salt structure with an alkyl halide. Among these, 2
- A copolymer of methacryloyloxyethyltrimethylammonium chloride and methyl methacrylate is preferably used as the membrane material.

Furthermore, a multicomponent copolymer containing a small amount of one or more other vinyl monomers in a methyl methacrylate copolymer containing a polymerizable monomer having a sulfonic acid group or a quaternary nitrogen group can also be produced. It can be used as the membrane material of the present invention as long as it does not lose its solubility in the membrane solvent.

Next, the two types of copolymers mentioned above, namely, a methyl methacrylate copolymer containing a monomer having a sulfonic acid group and a methyl methacrylate copolymer containing a monomer having a quaternary nitrogen group. The mixing ratio is such that the ratio of the number of sulfonic acid groups to the number of quaternary nitrogen groups in the ion-crosslinked separation membrane polymer to be produced is 5:1 to 5:1.
The ratio is in the range of 1:5, preferably 2:1 to 1:2, and more preferably the ratio of the sulfonic acid groups and quaternary nitrogen groups in the two types of copolymers is approximately 1:1 from the viewpoint of membrane strength. Correspondingly is the rate at which ion complexes are formed.

In addition, for membranes used in direct contact with blood, such as in artificial kidneys, artificial livers, and plasma separation therapy, the ratio of sulfonic acid groups to quaternary nitrogen groups in the two types of copolymers is 2:1 to 1:1. A mixing ratio that provides an anionic or neutral film of 1 is more preferred.

In addition, when mixing these two types of copolymers to prepare a membrane-forming stock solution, it is necessary to adjust the viscosity or mechanical strength during membrane formation into flat membranes or spinning into hollow fibers. It goes without saying that it is also possible to add a small amount of polymethyl methacrylate of various degrees of polymerization or isotactic polymethyl methacrylate, and these are included in the present invention.

The average molecular weight of these material polymers can be changed taking into consideration the mechanical properties required depending on the membrane forming or spinning method and the purpose of use of the membrane, but in general, the average molecular weight at the time of mixing is 100,000 or more. ,
Preferably it is around 200,000 to 800,000. (The average molecular weight is calculated from the viscosity formula [η ^] of the chloroform solvent of ^polymethyl methacrylate = ^4.8 It needs to be able to dissolve and finally be replaced by water. However, the present invention does not require an ion-shielding solvent, which is required for dissolving ordinary complex polyelectrolytes.

In the present invention, dimethyl sulfoxide or dimethyl formamide is used as a solvent. It is also possible to use a mixture of both. Dimethyl sulfoxide and dimethyl formamide are preferred solvents that can be used in combination with glycerin or formamide, which will be described later, to control and prepare precision membranes and ultrafiltration membranes of the present invention having large pore diameters. Among them, dimethyl sulfoxide is most preferable for membranes intended for medical use, as it can provide a membrane with wider permeability, even membranes with larger pore diameters, and has very low toxicity compared to dimethylformamide.

Furthermore, in the present invention, formamide or glycerin is added to the solvent system for preparing the membrane-forming (thread-spinning) stock solution in order to control the pore diameter. Glycerin and formamide can be used in combination with dimethyl sulfoxide or dimethyl formamide, which is the solvent of the present invention, to produce various kinds of products that have a permeability of the albumin of the present invention of 30% or more and a water UFR of 0.1 to 60/hr・m ²・mmHg. It is a preferred additive that allows controlled preparation of membranes. (Although glycerin and formamide are non-solvents for the polymethyl methacrylate-based ionic crosslinked polymer of the present invention, they are used as a solvent in combination with dimethyl sulfoxide and dimethyl formamide.) Among them, glycerin is less toxic than formamide. Very low and for medical purposes,
It can be said that it is preferable.

In order to obtain the polymethyl methacrylate crosslinked separation membrane of the present invention having an albumin permeability of 30% or more and a water UFR of 0.1 to 60/hr·m ² ·mmHg, 5 to 40% by weight of glycerin or formamide is required. Preferably, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF) is used as a solvent.

The amount of glycerin or formamide added varies depending on the composition of the raw material polymer (copolymerization rate, polymerization degree mixing ratio), the concentration of the raw material polymer in the membrane forming stock solution, the pore diameter of the intended membrane, the membrane forming method, etc. To give an example of the solvent composition, in the case of plasma separation applications, glycerin/DMSO = 12-20/88-80, formamide/DMSO = 20-30/80-70 (each value is weight %), For protein separation applications, etc.
Glycerin/DMSO=5-16/95-84, formamide/DMSO=12-24/around 88-76.

That is, as a general tendency, as the amount of glycerin or formamide added increases, the pore diameter increases and the permeability increases.

The concentration of the raw material polymer in the membrane forming stock solution depends on the type of solvent,
Although it varies depending on the composition, pore size of the desired membrane, membrane manufacturing method, etc., it is usually 5 to 30% by weight, preferably 10 to 30% by weight.
It is in the range of 20% by weight.

The membrane-forming stock solution thus obtained can be formed into a membrane or spun into hollow fibers by various known methods. For example, the stock solution may be cast onto a flat plate such as a glass plate or metal plate and then immersed in a coagulation bath to solidify it, or it may be extruded into a coagulation bath through a nozzle with long and narrow holes to form a film.
In this case, it is also possible to apply it onto a supporting fabric such as polyester taffeta. In addition to flat membranes, membranes of various shapes can be formed by spinning from a spinneret with concentric circular holes and forming them into a cylindrical or hollow fiber shape, or by spreading them on convex, concave, or other irregularly shaped surfaces and solidifying them. Obtainable.

Among these shapes, the hollow fiber type is most suitable for medical use because it has a high shear rate and can easily reduce the priming capacity.

Note that the membrane forming stock solution used in the method of the present invention gels in a low temperature range depending on the composition of the stock solution (mainly due to the solvent composition), so heating may be required when preparing the stock solution. In particular, when dimethyl sulfoxide is used as a solvent, the gelation (phase separation) temperature is high, approximately 100%
At temperatures below ℃, it becomes gel-like. For this reason, it is necessary to melt in a high temperature range, usually 110 to 130℃, preferably
The membrane forming stock solution is prepared by melting at around 115-125℃.
In film production (thread), this gelation phenomenon is utilized,
Membranes (threads) can also be formed by a method of injecting gas such as air without using an internal coagulating liquid in a dry-wet spinning method for forming hollow fibers. Furthermore, it goes without saying that an internal coagulating liquid (core liquid) can be used as in the usual dry-wet spinning or wet spinning method. In this case, the spinning dope is discharged from the annular spinning hole, and at the same time an internal coagulating liquid (for example, dimethyl sulfoxide or its aqueous solution, dimethylformamide or its aqueous solution, (alcohols or their aqueous solutions, etc.) is quantitatively flowed out and guided to a coagulation liquid bath located below the annular spinning hole.

As the coagulation bath, water, aliphatic lower alcohols, or a mixture thereof is generally used. Furthermore, in order to adjust the coagulation ability, a mixture may be used in which a solvent used for the stock solution, an inorganic salt, an acid, an alkali, etc. are added to the above-mentioned water or alcohol. However, when dimethyl sulfoxide or formamide is used as a solvent as in the present invention, it is preferable to use a mixture of these and water as a coagulation bath. Furthermore, the temperature of the coagulation bath at that time has a large effect on permeability, and generally a membrane exhibiting high permeability can be obtained on the high temperature side. Usually, the coagulation bath temperature is around 0°C to 95°C.

The membrane of the present invention does not undergo significant changes in permeation performance and mechanical properties over long periods of time when kept in a wet state. It is also possible to store it in a dry state by attaching a suitable wetting agent such as hydrous glycerin. In addition to the above, examples of wetting agents include ethylene glycol, polyethylene glycol, and various surfactants. Furthermore, it is also possible to change the permeation performance and mechanical properties (dimensional stability, etc.) of the membrane by heat treatment after film formation. Heat treatment is carried out under tension or without tension, and the temperature is usually 50 to 110°C, preferably 70 to 90°C.
is within the range of

As mentioned above, the separation membrane of the present invention is most suitable for medical applications, but it is also suitable for separating fine particles in a solution where the fine particles to be separated are deformable and form a suspension as a whole. It is also suitable for emulsion oils, oil/water separation, concentration of milk particles, concentration of latex liquid, clarification of beer, grape oil, sake, youth, etc. It can also be used for clarifying suspensions of inorganic particles, aseptic filtration, and producing ultrapure water.

Next, the present invention will be specifically explained using examples.

Example 1 500g of methyl methacrylate and sodium p-styrene sulfonate were mixed with water, 400ml and methanol.
Dissolved in 1600 ml of mixed solvent and polymerized at 55°C for 8 hours using 1.25 g of 2,2'-azobis-(2,4-dimethylvaleronitrile) as a radical initiator to remove parastyrene in the copolymer. Sulfonic acid content is 2.7 mol%, weight average molecular weight is 1.8×
10 ⁵ (Calculated from the single point method at a polymer concentration of 0.5 ^g /100 ml chloroform using the viscosity formula [η] = 4.8 × 10 ^-5 M ^0.8 of polymethyl methacrylate in chloroform solvent) A copolymer was obtained. .

Dissolve 500 g of methyl methacrylate and 45 g of 2-methacryloyloxyethyltrimethylammonium chloride in a mixed solvent of 400 ml of water and 1,600 ml of methanol, add 40 g of sodium chloride, and prepare 2,2'-
Azobis-(2,4-dimethylvaleronitrile)
Using 1.5g, polymerization was carried out at 55°C for 8 hours,
A granular copolymer was obtained in which the content of 2-methacryloyloxyethyltrimethylammonium in the copolymer was 2.5 mol % and the weight average molecular weight was 5.1×10 ⁵ .

Mixing 1 part of copolymer and 1 part of copolymer,
This was dissolved at 120°C in a dimethyl sulfoxide solvent containing 17% glycerin at a polymer concentration of 12%. This solution was cast at about 110° C. by inserting a 125 μm spacer between glass plates to adjust the film thickness, and after cooling to room temperature, it was solidified in ice water to obtain a devitrified flat film A having a thickness of 90 μm.

The pure water permeation rate UFRS of this membrane A is 24/hr・
m ² ·mmHg, the membrane rate (MFR) of the 0.2% albumin aqueous solution was 10/hr·m ² ·mmHg, and the albumin permeability was 98% or more.

Furthermore, this membrane A was incorporated into Amicon's thin-layer vortex filtration device (TCF2 type), and fresh rabbit blood (heparinized) was used.
7U/ml) under a pressure of 50mmHg, 1ml/min.
The plasma overrate when flowing at 60ml/hr・^m2・
mmHg, and the total protein transmittance was over 95%. Note that no leakage of platelets or red blood cells into this hyperplasma was observed.

Example 2 1 part of the copolymer of Example 1 and 1 part of the copolymer were mixed and dissolved at 120° C. in a dimethyl sulfoxide solvent containing 17% glycerin at a polymer concentration of 15%. This solution is used as a spinning stock solution, and water is poured into the hollow fiber as a core liquid from the annular spinning hole at a spindle temperature of 105℃.
The hollow fibers were spun while injecting a dimethyl sulfoxide solution containing 10%, introduced into a coagulation bath at about 90°C consisting of an aqueous solution containing about 10% dimethyl sulfoxide, and then passed through a glycerin bath and wound into a skein. The inner diameter of this hollow fiber was approximately 350μ, and the membrane thickness was approximately 70μ. Ten of these hollow fibers were housed in a small case with an effective length of approximately 12 cm, a test module with an effective area of 13 cm ² was prepared, and the permeation characteristics were tested.

The water permeability (Water UFR) of this test module was measured by applying a pressure of 50 mmHg to 8.1/hr・m ²・
mmHg, the membrane flux (MFU) of the 0.2% albumin aqueous solution was 3.8/hr·m ² ·mmHg, and the albumin permeability was 95% or more.

Furthermore, 2,500 of these hollow fibers were housed in a case with an effective length of 17.5 cm to create a module with an effective area of 0.5 m ² , and an extracorporeal perfusion experiment was conducted using a 16 kg dog.

Under pressure of 20 to 30 mmHg at a blood flow rate of 100 ml/min.
The plasma collection rate was stable from 2.1/hr to 1.8/hr (after 3 hours), and there were no problems such as hemolysis or coagulation, and the total protein amount in the excess plasma during that time was obtained by centrifugation from the corresponding blood. is almost the same as
No difference was observed in the constituent protein components.

Example 3 1 part of the copolymer of Example 1 and 1 part of the copolymer were mixed and dissolved at 130° C. in a dimethyl sulfoxide solvent containing 25% formamide at a polymer concentration of 20%. Spread this solution between glass plates at approximately 110°C.
A spacer of 125 μm was inserted and cast, and after cooling to room temperature, it was solidified in hot water at 75° C. to obtain a devitrified flat film B having a thickness of 120 μm.

The pure water permeability (UFRS) of this membrane B is 54/
hr・m ²・mmHg, and the membrane overrate (MFR) of 0.2% albumin aqueous solution is 18/hr・m ²・
mmHg and albumin transmittance were over 98%.

Example 4 1 part of the copolymer of Example 1 and 1 part of the copolymer were mixed, and this was dissolved at 120°C in a dimethylformamide solvent containing 30% glycerin at a polymer concentration of 20%, and the same as in Example 3 was prepared. The film was formed using a method with a film thickness of 110μ.
A devitrified flat membrane C was obtained.

The water permeability (UFRS) of this membrane C is 8.1/
hr・m ²・mmHg, and the membrane overrate (MFR) of 0.2% albumin aqueous solution is 2.3/hr・m ²・
mmHg and albumin transmittance were over 98%.

Example 5 One part of the copolymer of Example 1 and one part of the copolymer were dissolved at 125° C. in a dimethyl sulfoxide solvent containing 18% formamide at a polymer concentration of 20%. Using this solution as a stock solution, a film was formed in the same manner as in Example 1 using ice water in the coagulation bath to obtain a devitrified flat film D having a film thickness of 110 μm.

The water permeability (UFRS) of this membrane D is 1.4/
hr・m ²・mmHg, and the membrane overrate (MFR) of 0.2% albumin aqueous solution is 0.9/hr・m ²・mmHg.
The albumin transmission rate is 94%, and furthermore, 0.2
%γ-globulin (cattle, Seikagaku Corporation) The membrane transient rate (MFR) of the saline solution is 0.12/hr・m ²・
The γ-globulin transmittance was 45% at mmHg.

Furthermore, when a saline solution containing Bacillus pumilus spores (B.Pumilus E601) was passed through this membrane D, no spores were detected in the solution, and sterile filtration could be performed.

Example 6 One part of each of the same copolymers as in Example 1 was dissolved in a dimethyl sulfoxide solvent containing 14% glycerin at a polymer concentration of 15%, and a spinning stock solution was used for spinning according to the method of Example 2. Approximately 85μ hollow fibers were obtained.

The permeation performance was measured using a test module with a length of about 12 cm made by bundling 100 of these hollow fibers. The water permeability (water UFR) of this hollow fiber module is 2.8
/hr・m ²・mmHg, at 25℃ and 50mmHg,
Linear velocity of 0.2% albumin aqueous solution at inlet side: 10
The membrane overrate (MFR) at cm/sec.
1.7/hr・m ²・mmHg, albumin permeability is 96
It was %. Furthermore, the gamma globulin permeability was 62% and the beta lipoprotein permeability was 30% when measured through adult bovine serum (total protein amount 8.2 g/dl) under the same conditions as the albumin aqueous solution. When this adult bovine serum was added to a culture medium of double normal human cells at a concentration of 5% and 50% and a cell proliferation test was performed, both cases of addition of 5% and 50% showed that The cell proliferation ability was excellent, equivalent to that of newborn bovine serum, and no cell degeneration was observed when adult bovine serum was added at 5% or 50%.

Example 7 500g of methyl methacrylate and 29g of sodium p-styrene sulfonate were mixed with 630ml of water and methanol.
Dissolve in 1370ml of mixed solvent and add 60g of sodium chloride.
and 2,2′-azobis- as a radical initiator.
Using 2.5 g of (2,4-dimethylvaleronitrile), polymerization was carried out at 55°C for 8 hours, and the content of parastyrene sulfonic acid in the copolymer was 2.8 mol%, and the weight average molecular weight was ^4.9 A granular copolymer was obtained. Using a spinning stock solution in which 1 part of this copolymer and 1 part of the copolymer of Example 1 were mixed and dissolved in a dimethyl sulfoxide solvent containing 1.4% glycerin at a polymer concentration of 16%, a spinning stock solution was used that was passed through an annular spinning hole at a spinneret temperature of 102. The hollow fibers were spun at 10°C while dry air was injected into the interior of the hollow fibers, and then introduced into a coagulation bath at about 40°C consisting of an aqueous solution containing about 10% dimethyl sulfoxide to obtain hollow fibers.

The inner diameter of this hollow fiber was approximately 350μ, and the membrane thickness was approximately 80μ. Ten of these hollow fibers were housed in a small case with an effective length of approximately 12 cm to produce a test module with an effective area of 13 cm ² .

The water permeability (water UFR) of this hollow fiber module is
1.3/hr・m ²・mmHg, and the membrane overrate (MFR) when a 0.2% albumin aqueous solution is flowed at 25℃ and a pressure of 50mmHg at a linear velocity of 5cm/sec at the inlet.
is 0.6/hr・m ²・mmHg, and albumin permeability is
It was 68%.

Furthermore, when adult bovine plasma is passed under the same conditions as albumin aqueous solution, the excess amount is 75ml/hr・m ²・mmHg.
and the albumin to globulin ratio (A/G ratio)
The value changed from 0.7 for plasma to 2.0 for superfluid, and a considerable amount of albumin and globulin could be separated.

Claims (1)

[Claims] 1 Polymerizable monomer having sulfonic acid group from 0.5 to
A methyl methacrylate copolymer containing 10 mol% and a methyl methacrylate copolymer containing 0.5 to 10 mol% of a polymerizable monomer having a quaternary nitrogen group, and 5 to 40% by weight of glycerin or formamide. In dimethyl sulfoxide or dimethyl formamide, the number of sulfonic acid groups/number of quaternary nitrogen groups is 5/1 ~
Mixing ratio range of 1/5, polymer concentration 5-30% by weight
A method for producing a polymethyl methacrylate-based ionic crosslinked separation membrane, which comprises forming a membrane using a solution dissolved in the above as a membrane forming stock solution.