JPS6146206A - Manufacture of composite semipermeable membrane - Google Patents

Abstract

PURPOSE:To manufacture the titled composite semipermeable membrane without any defects in the membrane and having an excellent performance by immersing a water-contg. substrate membrane into a 1,4-butanediol soln., then drying the membrane to clog the pores, coating a polymer soln. for a semipermeable membrane on the substrate membrane, and volatilizing the solvent. CONSTITUTION:A water-soluble substrate membrane of a dried anisotropic ultrafiltration membrane, etc. is immersed in a 1,4-butanediol soln., preferably an about 1-60wt% aq. soln., the water is evaporated at about 0-100 deg.C to clog the pores so that the 1,4-butanediol may be left in the pores, and a dried ultrafiltration membrane is obtained. Then an about 0.05-10% soln., obtained by dissolving a polymer such as sulfonated polysulfone capable of forming a semipermeable membrane into a solvent which does not dissolve the substrate membrane, is coated on the dried ultrafiltration membrane as a substrate membrane. Then the solvent is volatilized to obtain a thin film composite semipermeable membrane without any defects in the membrane and having an excellent separation performance irrespective of the size of the pore of the substrate membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite semipermeable membrane, and more specifically, the present invention relates to a method for manufacturing a composite semipermeable membrane, and more specifically, a method for manufacturing a composite semipermeable membrane, in which a method for manufacturing a composite semipermeable membrane,
The present invention relates to a method for producing a composite semipermeable membrane that is made of a polymer of any molecular weight, has no membrane defects, and can form a thin semipermeable membrane with excellent separation performance.

A solution of a polymer capable of forming a thin semipermeable membrane such as a reverse osmosis membrane is applied onto a preformed supporting dry membrane as a base material, for example, a dried anisotropic ultrafiltration membrane. A method for obtaining a composite semipermeable membrane by evaporating the solvent and forming a semipermeable membrane on a base membrane is described, for example, in JP-A-50-99973 and JP-A-51-146379. Already known as described. However, in this method of applying a solution of a polymer capable of forming a semipermeable membrane onto a dry ultrafiltration membrane, in order to form a defect-free thin film, it is necessary to apply the polymer solution to at least the base membrane. It is necessary to have a predetermined molecular weight to the extent that it does not enter the micropores of the polymer, and the polymer used is subject to restrictions on its molecular weight.

To this end, conventionally, a hydrous ultrafiltration membrane is immersed in an aqueous glycerin solution and then dried so that the glycerin remains in the micropores of the membrane. There is a known method of manufacturing a composite semipermeable membrane by coating the membrane and evaporating the solvent.

However, when glycerin is used as an IJ in this way, depending on the type of polymer solution, even if it is coated on a dry ultrafiltration membrane and the solvent is evaporated, the glycerin may be resistant to water. This seems to be due to the high affinity, but membrane defects may occur or it may be difficult to obtain a composite semipermeable membrane with good separation performance.

As a result of intensive research to solve the above-mentioned problems, the present inventors have found that when using 1,4-butanediol as a plugging agent, a composite semipermeable membrane with no membrane defects and excellent separation performance has been developed. The present invention was based on the discovery that it can be obtained.

In the method for manufacturing a composite semipermeable membrane according to the present invention, a water-containing base membrane is
．． After being immersed in a 4-butanediol solution, dried and packed, a solution of a polymer capable of forming a semipermeable membrane is applied onto the base membrane, and the solvent is evaporated.

In the method of the present invention, the base membrane used is selected in consideration of the separation performance required of the semipermeable membrane formed thereon.For example, in order to obtain a composite semipermeable membrane with a high water permeation rate, The base membrane is preferably an ultrafiltration membrane with a high molecular weight cutoff, and the polymer constituting the base membrane is also dissolved in the polymer solution applied onto the ultrafiltration membrane. chosen not to do so. In the method of the present invention, an ultrafiltration membrane having a molecular weight cut off is usually in the range of 1000 to 200000, preferably about 100000.

In the method of the present invention, the water-containing base film as described above is
．． After immersion in a 4-butanediol solution, particularly preferably an aqueous solution, the water is evaporated, optionally by heating, so that the 1,4-butanediol remains substantially in the pores of the membrane, and the drying limit Obtain a filtration membrane. The concentration of the above 1,4-butanediol aqueous solution is 1 to 60% by weight, preferably 2 to 30% by weight.
% by weight, and a water-containing ultrafiltration membrane is usually immersed in such an aqueous solution for several minutes to several hours at room temperature. Thereafter, it is dried at a temperature in the range of 0 to 100°C, preferably 20 to 80°C, for several minutes to several hours.

A solution of a polymer capable of forming a semipermeable membrane is applied onto the dried ultrafiltration membrane as a base membrane obtained in this way, and the solvent is evaporated to form a composite semicontainer according to the present invention! You can make progress.

The semipermeable membrane-forming polymer is not particularly limited, for example, as long as it has separation activity as a reverse osmosis membrane and its solution dissolves the dry ultrafiltration membrane or does not swell the dry ultrafiltration membrane. For example, sulfonated polysulfone, cellulose acetate, polyamide, polyimide, polyamideimide, polyquinazolone, polyarylate, etc. can be used.

As mentioned above, the solvent for the polymer solution is not particularly limited as long as it does not dissolve the dry ultrafiltration membrane as the base membrane, and a solvent for the polymer solution may be appropriately selected depending on the polymer used. The concentration of the polymer in is usually 0.05 to 10
% by weight, preferably in the range of 0°1 to 5% by weight,
However, it is not limited to this range.

In particular, the method of the present invention provides chlorine resistance, in which a semipermeable membrane consisting of a homogeneous membrane of a sulfonated water-insoluble polysulfone polymer is integrally laminated on an anisotropic ultrafiltration membrane as a base membrane; It is useful as a method for producing a composite semipermeable membrane, which is used as an ultrafiltration membrane or a reverse osmosis membrane that has excellent ρ11 resistance, heat resistance, and compaction resistance.

Sulfonated polysulfones that can be preferably used in the present invention include partially sulfonated polysulfones obtained by partially sulfonating a polysulfone having a repeating unit represented by the following formula A, and a partially sulfonated polysulfone represented by the following formulas A and B. This is a sulfonated polysulfone copolymer obtained by sulfonating a linear polysulfone copolymer consisting of repeating units. All of these sulfonated polysulfones are hydrophilic, but water-insoluble.

A linear polysulfone copolymer having the above formulas A and B as repeating units has already been described in Canadian Patent No. 847.963, and a sulfonated product of this copolymer has also been described in JP-A-55 It is described in the publication No.-48222. That is, in this publication, substantially all of the repeating units of formula A are sulfonated by dissolving the polysulfone copolymer in concentrated sulfuric acid, but substantially all of the repeating units of formula A are sulfonated. describes the formation of hydrophilic sulfonated polysulfones, all of which remain in the non-sulfonated state. It is further noted that the sulfonated polysulfone copolymers are potentially useful as ultrafiltration membranes.

Furthermore, it is also stated that when a polysulfone consisting only of repeating units of formula A is similarly dissolved in concentrated sulfuric acid, this polysulfone is rapidly sulfonated to produce a completely water-soluble sulfonated polysulfone. .

However, the present inventors have discovered that by controlling the sulfonation conditions, a polysulfone consisting only of repeating units of formula A can be partially sulfonated so that it is hydrophilic but water-insoluble. Ta. For example, when polysulfone is kept as relatively coarse particles, 97~
This can be done by adding the polysulfone to 98% concentrated sulfuric acid and stirring gently at room temperature for several hours while the polysulfone remains undissolved.After this, the resulting viscous reaction solution is poured into water. , water-insoluble partially sulfonated polysulfones can be isolated.

In the present invention, such partially sulfonated polysulfone has an ion exchange capacity of 2 mm per gram of dry resin! /g or less, and the logarithmic viscosity measured at 30°C for a solution of 0.5 g of this polymer dissolved in 100n+1 of N-methyl-2-pyrrolidone (hereinafter, the method for measuring the logarithmic viscosity of sulfonated polysulfone is the same) It is.

) is 0.5 or more, preferably 0.7 or more.

In a polysulfone in which the repeating unit consists only of formula A,
When all of the aromatic rings sandwiched between two ether groups are monosulfonated, the theoretical ion exchange field (2) of such sulfonated polysulfone is 2.4 mm/Wk/g. Sulfonated polysulfone has an ion exchange capacity of 2 mm! /g or less. Ion exchange capacity is 2 mm/g
When it exceeds 0.00000, the partially sulfonated polysulfone becomes water-soluble and is unsuitable for use as a semipermeable membrane that often treats liquids containing aqueous media, and the logarithmic viscosity is 0.0000000000000000000000000 though,
This is because when it is smaller than 5, it is difficult to form a uniform thin film without defects such as pinholes on the base film.

In addition, a sulfonated polysulfone copolymer obtained by sulfonating a linear polysulfone copolymer having the above formulas A and B as repeating units can be obtained by dissolving the linear polysulfone copolymer in concentrated sulfuric acid and keeping it at room temperature for several hours. After stirring, the resulting viscous reaction solution can be easily isolated by pouring it into water. Regarding the degree of sulfonation, as mentioned above, substantially all of the repeating units of formula A are sulfonated, but substantially all of the repeating units of 2B remain in a non-sulfonated state. It can be easily controlled by using a copolymer with a different ratio of repeating units to NiB. Moreover, by controlling the sulfonation conditions, the sulfonation itself of the repeating unit of formula A can also be controlled.

The sulfonated polysulfone copolymer that can be preferably used in the present invention consists of 10 mol% or more of repeating units A and 90 mol% or less of repeating units B.

The sulfonic acid group possessed by the above-mentioned partially sulfonated polysulfone and sulfonated polysulfone copolymer (hereinafter may be collectively referred to as sulfonated polysulfone) is represented by the formula -503M, where M is hydrogen, Indicates an alkali metal or tetraalkylammonium. for example,
After sulfonating the polysulfone, the sulfonated polysulfone is washed with water and dried to obtain a sulfonated Bo1J sulfone having a free sulfonic acid group.

Further, by treating this sulfonated polysulfone with an aqueous solution of an alkali metal hydroxide or an alkali metal alcoholade, methanol, ethanol solution, etc., the sulfonic acid group can be converted into an alkali metal salt. As the alkali metal hydroxide, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. are used, and as the alkali metal alcoholade, for example, sodium methylate, potassium methylate, potassium ethylate, etc. are used.
Tetraalkylammoniums, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide,
By treating with a solution similar to the above, such as tetrapropylammonium hydroxide or tetrabutylammonium hydroxide, the corresponding tetraalkylammonium salt can be obtained.

In the present invention, organic solvents for preparing a membrane forming solution containing sulfonated polysulfone as described above include:
Alkylene glycol monoalkyl ethers in which the alkylene group has 2 or 3 carbon atoms and the alkyl group has 1 to 4 carbon atoms are preferably used. This is because, while this solvent generally has excellent solubility in sulfonated polysulfone and is highly volatile, it does not dissolve the polysulfone ultrafiltration membrane, which is useful as a support membrane, as described below. Examples of the alkylene glycol monoalkyl ether include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like.

In particular, ethylene glycol monomethyl ether is preferably used because it not only has excellent solubility for sulfonated polysulfone but also has high volatility.

However, depending on the degree of sulfonation of the sulfonated polysulfone used, it may not dissolve in the above alkylene glycol monoether or may only swell; It dissolves well in a mixed solvent prepared by adding a small amount of aprotic polar organic solvent to Such aprotic polar organic solvents include dimethyl sulfoxide, N-methyl-2-pyrrolidone, N, N
-dimethylformamide, N,N-dimethylacetamide, etc. are preferably used. In such a mixed solvent
1, the mixing ratio of the aprotic polar organic solvent is:
The above alkylene glycol monoalkyl ether 100
When the amount of the aprotic polar organic solvent is more than 5 parts by weight per 100 parts by weight of the alkylene glycol monoalkyl ether in the mixed solvent, the amount by weight is preferably 5 parts by weight or less, especially 2 parts by weight or less. teeth,
This is because when a membrane forming solution is applied onto a dry polysulfone ultrafiltration membrane, the ultrafiltration membrane dissolves or swells, making it difficult to obtain a composite semipermeable membrane with good membrane performance.

As mentioned above, the use of the above alkylene glycol monoalkyl ether or a mixed solvent of this and a small amount of the above aprotic polar organic solvent as a solvent for the membrane-forming solution makes it possible to remove the solvent by evaporation as described later. It is also advantageous in that substantially all of the solvent can be removed by heating, and a uniform thin film without defects can be obtained.

in membrane-forming solutions. The concentration of sulfonated polysulfone is
Although it is related to the thickness of the semipermeable membrane based on this polymer, it is usually 0.05 to 1% by weight, preferably 0.1 to 5% by weight.
is within the range of

Anisotropic ultrafiltration membrane for applying membrane forming solution.

As mentioned above, there are no particular limitations, but 1. Preferably, a polysulfone ultrafiltration membrane consisting of repeating units of the following formula C is used. This ultrafiltration membrane has a molecular weight cut-off of 1000~
Those in the range of 200,000 are preferred, particularly 10
Something around 0000 is good.

In order to make the above polysulfone ultrafiltration membrane into a dry base membrane according to the present invention, the water-containing membrane is immersed in an aqueous solution of 1,4-butanediol to replace the water in the water-containing membrane, and then the water is evaporated. and dry the membrane.

That is, after replacing the water contained in the micropores in the water-containing membrane with the above-mentioned plugging aqueous solution, heating is performed as necessary to evaporate and dry the plugging agent, leaving the plugging agent in the film and leaving a small amount. Hole collection 11
It suppresses it by 1t7. Therefore, the drying temperature is not particularly limited, but as mentioned above, it is usually 0 to 1
00°C, preferably in the range of 20 to 80°C. Next, the membrane forming solution is applied onto such a dry ultrafiltration membrane, and the solvent is evaporated off to obtain a composite semipermeable membrane according to the present invention. As mentioned above, by using alkylene glycol monoalkyl ether, which may contain a small amount of aprotic polar organic solvent, as the solvent for the membrane forming solution, substantially This is advantageous because all the solvent can be evaporated. After this,
If necessary, the solvent is completely evaporated off by heating. A heating temperature of 150° C. or lower is usually sufficient.

Incidentally, in order to promote evaporation of the solvent after the film-forming solution is applied onto the dry film, the film-forming solution may be heated in advance.

The thickness of the semipermeable membrane based on sulfonated polysulfone in the composite semipermeable membrane obtained in this way depends on the concentration of sulfonated polysulfone in the membrane forming solution and the amount of membrane forming solution applied to the dry membrane. Thinner is better to increase water permeation rate (and thicker is better to increase strength. Therefore, although not particularly limited, it is usually 0.0
It is preferably in the range of 1 to 5 μm.

Furthermore, a semipermeable membrane based on sulfonated polysulfone has no anisotropy and is homogeneous in the thickness direction, and no micropores are observed on the membrane surface even when observed using an electron microscope.

The composite semipermeable membrane according to the present invention has excellent chlorine resistance, pH resistance, heat resistance, etc., and is suitable for use as an ultrafiltration membrane or a reverse osmosis membrane. , even after long-term continuous use, without becoming compacted.
Maintain the initial high water permeation rate. In particular, a composite semipermeable membrane made of a sulfonated polysulfone copolymer in which the repeating unit of formula A is in the range of 50 to 10 mol% and the repeating unit of B is in the range of 50 to 90 mol% is Removal rate of 93% or more, preferably 99%
% or more, and the water permeation rate is sufficiently high for practical use.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way. In the Examples, the solute removal rate and water permeation rate of the obtained semipermeable membrane were measured at a concentration of 5000 p unless otherwise specified.
pm sodium chloride aqueous solution as a stock solution at a temperature of 25°C.
, a permeation experiment was conducted at a pressure of 50 kg/cd, and the values were determined using the following equations.

Example 1 (1) Production of polysulfone The repeating unit was of formula A according to the method described in Japanese Patent Publication No. 46-21458.

A polysulfone was produced.

That is, 13.2 g (0.12 mol) of hydroquinone was placed in a flask equipped with a stirrer, a nitrogen gas inlet tube, a water drain tube, and a thermometer, and 100 ml of sulfolane and 5 ml of xylene were added to the flask.
Added 0ml. Refluxing was carried out at 150° C. for 1 hour while stirring while heating with a mantle heater, and at this time, 3 ml of fishing rod was taken out.

Next, the temperature was lowered to 110° C., and 34.5 g (0.12 mol) of 4,4°-dichlorodiphenylsulfone and 20.7 g (0.15 mol) of potassium carbonate were added to start the polymerization reaction. After refluxing at 155°C for 50 minutes, the temperature was raised to 200°C while removing water for 50 minutes, and then refluxed for 20 minutes.
Refluxing was continued for 30 minutes at 00-215°C. The amount of water drawn off during this reaction was 3.6 ml.

After confirming that a film could be formed when a part of the reaction solution was applied to a glass plate and immersed in water, 80ml of sulfolane was added to the reaction solution, the temperature was lowered to 100°C,
20 ml of dichloromethane was added.

The reaction mixture thus obtained was poured into pure water to solidify the polysulfone, and the mixture was allowed to stand overnight. This was separated, pulverized with a mixer, washed with pure water and isopropyl alcohol, and then dried at a temperature of 80''C for 6 hours.

The polysulfone thus obtained is a reddish-colored granular material whose logarithmic viscosity (hereinafter referred to as the logarithmic viscosity of polysulfone) was measured at 47°C as a solution of 0.5 g of this polymer dissolved in 100 ml of p-chlorophenol. The measurement conditions were the same.) was 1.40.

(2) Production of partially sulfonated polysulfone 10 g of the polysulfone obtained as described above was added in the form of relatively coarse particles to 80+ml of 97% concentrated sulfuric acid, and the polysulfone was initially left undissolved, and the polysulfone was slowly stirred at room temperature. The mixture was stirred and reacted for 4 hours to obtain a blackish brown viscous reaction liquid. This was placed in a water bath to solidify the partially sulfonated polysulfone. After washing with water, 0.5N sodium hydroxide aqueous solution 8
The polymer was left overnight in 0.0ml of water and then washed until the washing solution became neutral, followed by vacuum drying at 30°C for 7 hours. The pale yellow granular partially sulfonated polysulfone thus obtained was water-insoluble, had a logarithmic viscosity of 3.00, and an ion exchange capacity of 1°92 meq/g.

(3) Manufacture of composite semipermeable membrane Consisting of repeating units of the above formula C, average molecular weight 20,000
An anisotropic ultrafiltration membrane having a repeating unit of the formula C, which has a removal rate of 10% for polyethylene glycol and a molecular weight cut off of 1oooooo, is immersed in hot water at a temperature of 80 ° C. for 1 hour. After heat treatment at 25℃,
The membrane was immersed in a 0% 1.4-butanediol aqueous solution for 1 hour, and then left in a drying path at about 60° C. for 5 minutes to obtain a dry ultrafiltration membrane.

The above partially sulfonated polysulfone was dissolved in ethylene glycol monomethyl ether and 1.01! % of the polymer solution was prepared, this was applied onto the dry ultrafiltration membrane, and the solution was left at room temperature to evaporate and remove almost all the solvent, and then heated at a temperature of 60°C for 5 minutes. As a result, a composite semipermeable membrane according to the present invention was obtained.

- The performance of this composite semipermeable membrane was a removal rate of 45.9% and a water permeation rate of 5.6 g/rd·day.
1 In addition, a composite semipermeable membrane was obtained in the same manner as above except that a 20% aqueous 1,4-butanediol solution was used. Membrane performance: removal rate 42.3% water permeability 9.7nr
It was /d day.

Comparative Example 1 For comparison, a composite semipermeable membrane was obtained in the same manner as in Example 1 without performing plugging with an aqueous 1,4-butanediol solution. Membrane performance: removal rate 50.0%, water permeation rate 1.3n
? /rrr-day.

Further, a composite semipermeable membrane was obtained in the same manner as in Example 1, except that a 10% aqueous glycerin solution was used as the packing solution. Membrane performance is removal rate 28.9%, water permeation rate 7.4n? /m
・It was day.

Example 2 In Example 1, when packing the ultrafiltration membrane as a base membrane, the ultrafiltration membrane was not heat-treated with hot water and
A composite was prepared in the same manner as in Example 1, except that it was immersed in a 10% 1.4-butanediol aqueous solution of 0"C for 1 hour, and then left in a drying path at about 60°C for 5 minutes to form a dry film. A semipermeable membrane was prepared.This composite semipermeable membrane had a removal rate of 47.2%,
Water permeability rate 5.7 n? It was /d day.

Example 3 A composite semipermeable membrane was prepared in exactly the same manner as in Example 1, except that when applying the membrane-forming solution of partially sulfonated polysulfone onto the dry membrane, membrane-forming solutions with various concentrations were used. was prepared. Table 1 shows the membrane performance of each of the composite semipermeable membranes thus obtained.

Example 4 In the same manner as in Example 1, except that resorcinol was used instead of hydroquinone,
- A polysulfone consisting of a repeating unit of
．． 80, partially sulfonated polysulfone with an ion exchange capacity of 1.9 meq/g was obtained.

A composite semipermeable membrane was prepared in the same manner as in Example 1 using this partially sulfonated polysulfone. The membrane performance was a removal rate of 47.0% and a water permeation rate of 5.3 rrrf/rrr·day.

Example 5 A polysulfone consisting of a repeating unit of formula A3 was prepared in the same manner as in Example 1 except that catechol was used instead of hydroquinone, and this was partially converted into a sulfone in the same manner as in Example 1. , logarithmic viscosity 3
．． A partially sulfonated polysulfone with an ion exchange capacity of 0 and an ion exchange capacity of 1.8 meq/g was obtained.

A composite semipermeable membrane was prepared in the same manner as in Example 1 using this partially sulfonated polysulfone. Membrane performance is removal rate 46.3%, water permeation rate 5.3rd/n?・It was day.

Example 6 A composite semipermeable membrane was prepared in the same manner as in Example 1 using an aqueous 1,4-butanediol solution having the concentrations shown in Table 2.

Using an aqueous solution of polyethylene glycol (average molecular weight 20,000) with a concentration of 500 ppm as the stock solution, the temperature was 25°C.
A permeation experiment was conducted under the conditions of , and a pressure of 30 kg/cd.

The results are shown in Table 2.

Table 2 Example 71 (Evaluation of heat resistance) The composite semipermeable membrane obtained in Example 1 was placed in hot water at 95°C for 30 minutes.
The sample was immersed for 0 minutes, and the removal rate and water permeation rate were measured. Furthermore,
Repeat this 30 minute immersion in hot water,
The removal rate and water permeation rate were measured in the same manner. The results are shown in Table 3. The composite semipermeable membrane according to the present invention does not substantially change its membrane performance even after repeated immersion in hot water.
Therefore, it can be suitably used for treating high temperature liquid mixtures.

Table 3 (Acid Resistance) The composite semipermeable membrane obtained in Example 1 was immersed in distilled water for 2 hours, and then in a 0.5N aqueous hydrochloric acid solution at 25° C. for 2 hours, and then the membrane performance was measured. Removal rate is 46.0%, water permeation rate is 5.6n? /n? - It is understood that the composite semipermeable membrane of the present invention has excellent acid resistance.

(Alkali resistance) The composite semipermeable membrane obtained in Example 1 was immersed in distilled water for 2 hours, and then in a 0.5N aqueous sodium hydroxide solution at 25° C. for 2 hours, and then the membrane performance was measured. Removal rate is 45
．． 2%, water permeation rate is 6. On? /mF·day, and it is understood that the composite semipermeable membrane of the present invention has excellent alkali resistance.

Example 8 (1) Production of polysulfone copolymer A linear polysulfone consisting of 57 mol% of repeating units of formula A+ and 43 mol% of repeating units of formula A+ was prepared according to the method described in Japanese Patent Publication No. 46-21458. A copolymer was produced.

That is, 4,4'-dihydroxydiphenylsulfone 15
, Og (0.06 mol) and hydroquinone 8.8 g (0
, 08 mol) was placed in a flask equipped with a stirrer, nitrogen gas inlet tube, water drain tube and thermometer, and sulfolane 20
0a+1 and 100ml of xylene were added.

155 while stirring while heating with a mantle heater.
Refluxing was carried out at ℃ for 1 hour, during which time 5.6+ wl of water was extracted.

Next, the temperature was lowered to 110°C, and 40.2 g (0.14 mol) of 4,4''-dichlorodiphenylsulfone and 27.6 g (0.20 mol) of potassium carbonate were added to start the polymerization reaction. 162°C. After refluxing for 1 hour, the temperature was raised to 200°C while removing water for 2.5 hours, and
Refluxing was continued for 4 hours at 00-215°C. The amount of water drawn off during this reaction was 2.0 ml.

After confirming that a film could be formed when a portion of the reaction solution was applied to a glass plate and immersed in water, the temperature was lowered to 100°C and dichloromethane 20II11 was added.

The reaction mixture thus obtained was poured into pure water to solidify the polysulfone copolymer, washed with pure water and then with acetone, and then dried at 80° C. for 6.5 hours.

The polysulfone copolymer thus obtained (yield: 1
00%) was a pale yellow particulate material, and the logarithmic viscosity of this copolymer was 0.84 c+d/g.

(2) Production of sulfonated polysulfone copolymer 10 g of the polysulfone copolymer obtained as described above was dissolved in 80 ml of 97% concentrated sulfuric acid, stirred at room temperature for 4 hours, and a blackish brown viscous A reaction solution was obtained. This was placed in a water bath to solidify the sulfonated polysulfone copolymer. After washing with water, 0.5N sodium hydroxide aqueous solution 8
00ml overnight. Next, the polymer was washed until the washing solution became neutral, and then vacuum-dried at 60° C. for 5 hours.

The sulfonated polysulfone copolymer thus obtained had a logarithmic viscosity of 0.84 and an ion exchange capacity of 1.2 mm/1 t/g.

(3) Production of composite semipermeable membrane The same polysulfone ultrafiltration membrane used in Example 1 was immersed in hot water at a temperature of 80°C for 1 hour! After heat treatment, the membrane was immersed in a 10% aqueous 1.4-butanediol solution at a temperature of 25°C for 1 hour, and then left in a dryer at about 60°C for 5 minutes to obtain a dry semipermeable membrane.

Dissolving the sulfonated polysulfone copolymer in ethylene glycol monomethyl ether to prepare a 1.0% by weight polymer solution, applying this onto the dry ultrafiltration membrane and leaving it at room temperature, After removing almost all the solvent by evaporation, it was heated at a temperature of 50'C for 5 minutes to obtain a composite semipermeable membrane according to the present invention.

The performance of this composite semipermeable membrane is that the removal rate is 85.7% and the water permeation rate is 2.3n? /rrr・day.

Example 9 In Example 8, when packing the ultrafiltration membrane as a support membrane, the ultrafiltration membrane was not heat-treated with hot water and
It was immersed in a 10% 1,4-butanediol aqueous solution at 0°C for 1 hour, and then left in a dryer at about 60°C for 5 minutes.
A composite semipermeable membrane was prepared in the same manner as in Example 8 except that a dry semipermeable membrane was used. The performance of this composite semipermeable membrane is that the removal rate is 86
．． 0%, and the water permeation rate was 2.4 d/d·day.

Similarly, various polysulfone copolymers having different ratios of repeating units of formula A1 and repeating units of NiB were prepared,
These were sulfonated and used to prepare composite semipermeable membranes. Table 4 shows the performance of these membranes.

Example 10 1. Sulfonated polysulfone copolymer consisting of 43 mol% of repeating units of formula A+ and 57 mol% of repeating units of formula A+ obtained in Example 8. When applying Olit% ethylene glycol monomethyl ether solution onto a dry ultrafiltration membrane, the ultrafiltration membrane was coated with various concentrations of
, A composite semipermeable membrane was prepared by applying a membrane forming solution onto an ultrafiltration membrane in exactly the same manner as in Example 1, except that the ultrafiltration membrane was immersed in an aqueous solution of 4-butanediol. Table 2 shows the membrane performance of each of the composite semipermeable membranes thus obtained.

For comparison, a composite semipermeable membrane was prepared in the same manner as in Example 1 without being subjected to packing treatment. The membrane performance of these membranes is also shown in Table 5.

Example 11 A 1.0 wt% ethylene glycol monomethyl ether solution of the sulfonated polysulfone copolymer consisting of 43 mol% of repeating units of formula A+ and 57 mol% of repeating units of NiB obtained in Example 9 was prepared. The membrane forming solution was applied onto the dry ultrafiltration membrane in exactly the same manner as in Example 1 except that the concentration of the membrane forming solution was changed to form a composite semipermeable membrane. Prepared. Table 6 shows the membrane performance of each of the composite semipermeable membranes thus obtained.

Table 6 Example 12 1 g of the sulfonated polysulfone copolymer consisting of 17 mol % of repeating units of formula A and 83 mol % of repeating units of formula B obtained in Example 9 was mixed with 99 g of ethylene glycol monomethyl ether and N, N-dimethylform 7mide 1
A membrane forming solution was prepared by dissolving the mixture in a mixed solvent consisting of g and removing foreign substances using a 108 m filter paper.

In the same manner as in Example 8, this membrane forming solution was applied onto a dry ultrafiltration membrane at a temperature of 25°C, and after evaporating most of the solvent at a temperature of 25°C, it was heated at 60°C for 5 minutes. The solvent was removed to obtain a composite semipermeable membrane.

The performance of this composite semipermeable membrane was a removal rate of 93.6% and a water permeation rate of 0.5 i/rd·day.

Example 13 A polysulfone copolymer consisting of 57 mol% of the repeating unit of formula A2 and 43 mol% of the repeating unit of NiB was produced in the same manner as in Example 8, except that resorcinol was used instead of hydroquinone. A composite was prepared and sulfonated as in Example 8 to give a log viscosity of 0.93c.
A sulfonated polysulfone copolymer having an ion exchange capacity of 10.913 mm/g and an ion exchange capacity ff of 10.913 mm/g was obtained.

A composite semi-yi membrane was prepared in the same manner as in Example 8 using this sulfonated polysulfone copolymer.

Membrane performance is removal rate 91.2%, water permeation rate 1.8nr10
It was f day.

Example 14 In Example 8, a polysulfone copolymer consisting of 57 mol% of repeating units of formula A and 43 mol% of repeating units of NiB was prepared in the same manner as in Example 1, except that catechol was used instead of hydroquinone. A polymer was prepared and sulfonated in the same manner as in Example 8 to obtain a sulfonated polysulfone copolymer having a logarithmic viscosity of 1.02 and an ion exchange capacity of 1.03 meq/g.

Using this partially sulfonated polysulfone copolymer, a semipermeable membrane having a thickness of 0.3 μm without membrane defects was prepared in the same manner as in Example 8. Membrane performance is removal rate 88.9%, water permeation rate 1.8n? /nf・day.

Example 15 10 g of the sulfonated polysulfone copolymer consisting of 43 mol% of repeating units and 57 mol% of repeating units obtained in Example 9 was dissolved in 97% concentrated sulfuric acid, stirred and reacted for 4 hours to form a blackish brown viscous product. A reaction mixture was obtained. After the reaction, the reaction mixture was put into a water bath to coagulate the polymer, washed with pure water until the washing solution became neutral, and dried at 60°C for 7 hours to give a logarithmic viscosity of 1.03 ad/ A sulfonated polysulfone copolymer having an ion exchange capacity of 1 g and flk of 1.0 θ mm was obtained.

A membrane forming solution was prepared by dissolving 0.5 g of this sulfonated polysulfone copolymer in 99.5 g of ethylene glycol monomethyl ether, and using this solution, a composite semipermeable membrane was obtained in the same manner as in Example 8.

The performance of this composite semipermeable membrane was a removal rate of 96.5% and a water permeation rate of 1.15 tyr/nf·day.

Comparative Example 2 In Example 8, 1offi was used as the packing side wood solution.
Implementation 1 except that a % glycerin aqueous solution was used.
A composite semipermeable membrane was prepared in the same manner as in Example 8. The performance of this composite semipermeable membrane is 28.9% removal rate and water permeation rate? , 42n?
/rrf-day, and the removal rate was significantly lower than that in the case of 1,4-butanediol as the plugging agent.

Example 16 (Evaluation of heat resistance) Composite semipermeable membrane obtained in Example 8 and li! obtained in Example 9. b It was immersed in hot water at 95°C for 30 minutes, and the removal rate and water permeation rate were measured. Furthermore, in this way, 30
The removal rate and water permeation rate were measured in the same manner by repeating the soaking operation for minutes. As the results are shown in Table 7, the composite semipermeable membrane according to the present invention does not substantially change its membrane performance even after repeated immersion in hot water, and therefore is suitable for processing hot liquid mixtures. It can be suitably used for.

(Acid resistance) A composite semipermeable membrane obtained in the same manner as in Example 9 b was dissolved in distilled water for 2 hours.
The membrane performance was measured after immersion for 2 hours and then immersion in a 0.5 N aqueous hydrochloric acid solution at 25° C. for 2 hours.

As shown in Table 8, the composite semipermeable membrane of the present invention had no change in performance before and after immersion, and had improved acid resistance (alkali resistance). Place the membrane in distilled water 2
The membrane performance was measured after immersion for an hour and then in a 0.5N aqueous sodium hydroxide solution at 25°C for 2 hours. As the results are shown in Table 8, it is understood that the composite semipermeable membrane of the present invention has excellent alkali resistance, with membrane performance unchanged before and after immersion.

Example 11 After immersing the composite semipermeable membrane of Example 3 in distilled water for 2 hours,
After immersing in a 0.5N hydrochloric acid aqueous solution at 0.degree. C. for 2 hours and washing with distilled water, the membrane was dried at 25.degree. C. for 2 hours. Membrane performance after rewetting is 99.5% removal rate and 0.3 water permeation rate.
n? /rrr・day.

Claims (1)

[Claims] (1) A water-containing base film is immersed in a 1,4-butanediol solution, dried, and packed, and then a solution of a polymer capable of forming a semipermeable membrane is applied onto the base film, and a solvent A method for producing a composite semipermeable membrane, characterized by evaporating.