JP2019123858A - Aromatic polysulfone resin and membrane thereof - Google Patents

Abstract

To provide an aromatic polysulfone resin which can form a membrane having a small thermal shrinkage.SOLUTION: The aromatic polysulfone resin has repeating units represented by the formulas (I) and (II) in the figure, where the ratio (m:n) of the molar content (m) of the repeating units represented by the formula (I) and the molar content (n) of the repeating units represented by the formula (II) is between 1:2000 and 1:200. (The hydrogen atoms in the phenylene groups of the formulas (I) and (II) may each independently be substituted with an alkyl group, aryl group, or halogen atom.)SELECTED DRAWING: None

Description

  The present invention relates to aromatic polysulfone resins and membranes thereof.

  Aromatic polysulfone resins are used in various applications because they are excellent in heat resistance and chemical resistance. One of the applications is a porous membrane material used for filtration such as ultrafiltration and microfiltration. For example, Patent Document 1 describes that an aromatic polysulfone resin is used as a material of the porous hollow fiber membrane.

Unexamined-Japanese-Patent No. 2006-230459

  When a hollow fiber membrane using such a resin is used for an artificial dialysis membrane, the hollow fiber membrane may be sterilized. Examples of the sterilization treatment include heat treatment, radiation treatment, steam sterilization treatment and the like. When steam sterilization is mentioned as an example of sterilization, steam sterilization is performed under high temperature and high pressure conditions of a temperature of 121 ° C. and a pressure of 0.2 MPa. At this time, if the heat contraction rate of the hollow fiber membrane is large, cracks may occur in the hollow fiber membrane due to the heat contraction of the hollow fiber membrane.

  Furthermore, even if the hollow fiber membrane is not sterilized, the same problem is considered to occur when the membrane is heated during production or use of the hollow fiber membrane.

  Further, the problem that a crack is generated in the hollow fiber membrane due to the thermal contraction of the hollow fiber membrane is a problem common to not only the hollow fiber membrane for an artificial dialysis membrane but also a flat membrane and a tubular membrane. Moreover, the above-mentioned subject is a common subject whether it is a single layer film or a multilayer film.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an aromatic polysulfone resin from which a film having a small thermal contraction rate can be obtained, and a film thereof.

（式（Ｉ）および式（ＩＩ）のフェニレン基にある水素原子は、それぞれ独立に、アルキル基、アリール基またはハロゲン原子で置換されていてもよい。） In order to solve the above problems, one aspect of the present invention has a repeating unit represented by the following formula (I) and the formula (II), and the molar content (m) of the repeating unit represented by the formula (I) Provided an aromatic polysulfone resin in which the ratio (m: n) of the molar content (n) of the repeating unit represented by the formula (II) is 1: 2000 to 1: 200.

(The hydrogen atoms in the phenylene group of Formula (I) and Formula (II) may be each independently substituted with an alkyl group, an aryl group or a halogen atom.)

  One aspect of the present invention provides a membrane comprising the aromatic polysulfone resin described above.

  In one embodiment of the present invention, a porous membrane may be used.

  According to one aspect of the present invention, there is provided an aromatic polysulfone resin and a membrane thereof which can provide a membrane having a low thermal shrinkage.

[Aromatic polysulfone resin]
The aromatic polysulfone resin is typically a divalent aromatic group (a residue obtained by removing two hydrogen atoms bonded to the aromatic ring from an aromatic compound) and a sulfonyl group (-SO _2- ) And a resin having a repeating unit containing oxygen and an oxygen atom. The aromatic polysulfone resin preferably has a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as "repeating unit (1)") from the viewpoint of heat resistance and chemical resistance, and further, it is more preferable. A repeating unit represented by the following formula (2) (hereinafter sometimes referred to as "repeating unit (2)") or a repeating unit represented by the following formula (3) (hereinafter referred to as "repeating unit (3) And the like))) and the like may be included.

_{^{(1) -Ph 1 -SO 2 -Ph}} 2 -O-

Ph ¹ and Ph ² each independently represent a phenylene group. The hydrogen atoms in the phenylene group may be each independently substituted with an alkyl group, an aryl group or a halogen atom.

^{(2) -Ph 3 -R-Ph} 4 -O-

Ph ³ and Ph ⁴ each independently represent a phenylene group. The hydrogen atoms in the phenylene group may be each independently substituted with an alkyl group, an aryl group or a halogen atom. R represents an alkylidene group, an oxygen atom or a sulfur atom.

(3)-(Ph ⁵ ) _n- O-

Ph ⁵ represents a phenylene group. The hydrogen atoms in the phenylene group may be each independently substituted with an alkyl group, an aryl group or a halogen atom. n represents an integer of 1 to 3; When n is 2 or more, multiple Ph ^{5 s} may be identical to or different from each other.

The phenylene group represented by any of Ph ^{1 to} Ph ⁵ may be a p-phenylene group, an m-phenylene group or an o-phenylene group, but p It is preferably -phenylene group.

  Examples of the alkyl group which may substitute a hydrogen atom in the phenylene group are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t- A butyl group, n-hexyl group, 2-ethylhexyl group, n-octyl group and n-decyl group are mentioned. The carbon number of the above alkyl group is, for example, 1 to 10.

  Examples of the aryl group which may substitute a hydrogen atom in the phenylene group include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 1-naphthyl group and 2-naphthyl group. Be The carbon number of the aryl group is, for example, 6 to 20.

  When the hydrogen atom in the phenylene group is substituted by these groups, the number thereof is independently, for example, 2 or less, preferably 1 or less, for each of the phenylene groups.

  Examples of the alkylidene group which is R include a methylene group, an ethylidene group, an isopropylidene group and a 1-butylidene group, and the carbon number thereof is, for example, 1 to 5.

  The aromatic polysulfone resin preferably has the repeating unit (1) in an amount of 50 mol% or more, more preferably 80 mol% or more, based on the total of all the repeating units. It is further preferred to have only 1). In addition, aromatic polysulfone resin may have 2 or more types of repeating units (1)-(3) each independently.

  The aromatic polysulfone resin of this embodiment is a repeating unit represented by the following formula (I) (hereinafter sometimes referred to as “repeating unit (I)”) and a repeating unit obtained from the repeating unit (1) and It has a repeating unit represented by formula (II) (hereinafter sometimes referred to as "repeating unit (II)").

  In the aromatic polysulfone resin of this embodiment, the ratio (m: n) of the molar content (m) of the repeating unit (I) to the molar content (n) of the repeating unit (II) is 1: 2000 to It is 1: 200. Although the cause is unknown if the ratio (m: n) is in the range of 1: 2000 to 1: 200, the thermal shrinkage of the film containing the aromatic polysulfone resin is that of the conventionally known aromatic polysulfone resin Small compared to the heat shrinkage rate. The method of measuring the thermal contraction rate will be described later.

  The ratio (m: n) of the molar content (m) of the repeating unit (I) to the molar content (n) of the repeating unit (II) is preferably 1: 1500 to 1: 250, 1: 1000 to 1: 300 is more preferred.

  In the present specification, the ratio (m: n) of the molar content (m) of the repeating unit (I) to the molar content (n) of the repeating unit (II) includes boundary values.

  The hydrogen atoms in the phenylene group of repeating unit (I) and repeating unit (II) may be each independently substituted with an alkyl group, an aryl group or a halogen atom.

  The ratio (m: n) of the molar content (m) of the repeating unit (I) to the molar content (n) of the repeating unit (II) can be determined from the charged amount (mol) of the raw material monomer used it can.

  In addition, it can be confirmed that all the used raw material monomers are consumed in the polymerization (polycondensation) reaction.

  The reduced viscosity of the aromatic polysulfone resin is, for example, 0.3 dL / g or more, preferably 0.4 dL / g or more and 0.9 dL / g or less, and more preferably 0.45 dL / g or more and 0.80 dL / g or less. The higher the reduced viscosity of the aromatic polysulfone resin, the easier it is to improve the heat resistance, the strength and the rigidity. However, if it is too high, the processability at the time of producing the porous membrane by the method described later becomes insufficient. Therefore, the reduced viscosity of the aromatic polysulfone resin is preferably 0.3 dL / g or more and 0.9 dL / g or less.

  The aromatic polysulfone resin can be produced by polycondensation of a dihalogenosulfone compound and a dihydroxy compound corresponding to the repeating unit constituting it.

  For example, a resin having a repeating unit (1) uses a compound represented by the following formula (4) as the dihalogenosulfone compound (hereinafter sometimes referred to as "compound (4)"), and the following formula as a dihydroxy compound It can manufacture by using the compound (Hereinafter, it may be mentioned "compound (5).") Represented by (5).

  In addition, a resin having a repeating unit (1) and a repeating unit (2) uses a compound (4) as a dihalogenosulfone compound and a compound represented by the following formula (6) as a dihydroxy compound (hereinafter referred to as “compound 6) "can be used to produce.

  In addition, the resin having the repeating unit (1) and the repeating unit (3) is a compound represented by the following formula (7) as a dihydroxy compound using a compound (4) as the dihalogenosulfone compound (hereinafter referred to as “compound (4) 7) ") can be used.

(4) X ¹ -Ph ¹ -SO ₂ -Ph ² -X ²

X ¹ and X ² each independently represent a halogen atom. Ph ¹ and Ph ² are as defined above.

^{(5) HO-Ph 1 -SO} 2 -Ph 2 -OH

Ph ¹ and Ph ² are as defined above.

(6) HO-Ph ³ -R-Ph ⁴ -OH

Ph ³ , Ph ⁴ and R are as defined above.

(7) HO- (Ph ⁵ ) _n -OH

Ph ⁵ and n are as defined above.

  The aromatic polysulfone resin of the present embodiment can be produced by polycondensation of a compound (4) corresponding to the repeating unit (I) and a compound (5).

  In the aromatic polysulfone resin of the present embodiment, the ratio (m: n) is 1: 2000 to 1: 200 in the aromatic polysulfone resin having the repeating unit (1) to the repeating unit (3). It is also possible to produce a mixture of resins having repeating units (I).

  The resin having a repeating unit (I) uses a compound represented by the following formula (III) as the compound (4) (hereinafter sometimes referred to as "compound (III)") and a compound (5) as a dihydroxy compound Can be produced by using a compound represented by the following formula (IV) (hereinafter sometimes referred to as “compound (IV)”).

X ¹ and X ² are as defined above. The hydrogen atoms in the phenylene group may be each independently substituted with an alkyl group, an aryl group or a halogen atom.

  Further, the resin having the repeating unit (I) uses a compound represented by the following formula (V) (hereinafter sometimes referred to as "compound (V)") as the compound (4), and the following as a dihydroxy compound It can manufacture by using the compound (Hereinafter, it may be mentioned "compound (VI).") Represented by Formula (VI).

X ¹ and X ² are as defined above. The hydrogen atoms in the phenylene group may be each independently substituted with an alkyl group, an aryl group or a halogen atom.

  The polycondensation is preferably carried out in a solvent using an alkali metal salt of carbonic acid. The alkali metal salt of carbonic acid may be an alkali carbonate which is a normal salt, may be an alkali bicarbonate (alkali hydrogen carbonate) which is an acid salt, or may be a mixture of both. As sodium carbonate and potassium carbonate are preferably used, and sodium bicarbonate and potassium bicarbonate are preferably used as alkali bicarbonate. As the solvent, dimethylsulfoxide, 1-methyl-2-pyrrolidone, sulfolane (1,1-dioxochilane), 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, dimethylsulfone Organic polar solvents such as diethyl sulfone, diisopropyl sulfone and diphenyl sulfone are preferably used.

  In the polycondensation, if a side reaction does not occur, the molar ratio of the dihalogenosulfone compound to the dihydroxy compound is closer to 1: 1, the use amount of the alkali metal salt of carbonic acid is higher, and the polycondensation temperature is higher. Also, the longer the polycondensation time, the higher the degree of polymerization of the resulting aromatic polysulfone resin, and the higher the reduced viscosity.

  In fact, side reactions such as substitution reaction of a halogeno group to a hydroxyl group or depolymerization occur due to by-product alkali hydroxide and the like, and the degree of polymerization of the resulting aromatic polysulfone resin tends to be reduced by this side reaction, Viscosity tends to decrease.

  For this reason, the molar ratio of the dihalogenosulfone compound to the dihydroxy compound, the alkali metal salt of carbonic acid, in consideration of the degree of this side reaction, so as to obtain an aromatic polysulfone resin having a desired reduced viscosity. It is preferable to adjust the amount used, the polycondensation temperature and the polycondensation time.

[Membrane containing aromatic polysulfone resin]
The membrane containing the aromatic polysulfone resin of the present embodiment may be, for example, a flat membrane, a tubular membrane, or a hollow fiber membrane. In addition, the film containing the aromatic polysulfone resin of this embodiment may be a single layer film or a multilayer film. In the case of a multilayer film, it may be a multilayer film having two or more layers containing only the aromatic polysulfone resin of the present embodiment, or one or more layers containing the aromatic polysulfone resin of the present embodiment. And a multilayer film having one or more other layers.

  For example, when a hollow fiber membrane containing a resin is used for an artificial dialysis membrane, the hollow fiber membrane may be subjected to steam sterilization treatment using an autoclave or the like. The steam sterilization process is performed under high temperature and high pressure conditions of, for example, a temperature of 121 ° C. and a pressure of 0.2 MPa. At this time, if the heat contraction rate of the hollow fiber membrane is large, cracks may occur in the hollow fiber membrane due to the heat contraction of the hollow fiber membrane.

  Further, the problem that a crack is generated in the hollow fiber membrane due to the thermal contraction of the hollow fiber membrane is a problem common to not only the hollow fiber membrane for an artificial dialysis membrane but also a flat membrane and a tubular membrane. Moreover, the above-mentioned subject is a common subject whether it is a single layer film or a multilayer film.

  As described above, in the aromatic polysulfone resin of this embodiment, the ratio (m: n) of the molar content (m) of the repeating unit (I) to the molar content (n) of the repeating unit (II) is , 1: 2000 to 1: 200. The thermal contraction rate of a film containing such an aromatic polysulfone resin is smaller than that of conventionally known aromatic polysulfone resins, although the cause is unknown. Therefore, even if heat treatment is performed under high temperature and high pressure conditions, it is considered that there is little possibility of the occurrence of cracks.

  The thermal contraction rate of the film of this embodiment is a porous film containing an aromatic polysulfone resin, and a value measured by the following method is adopted.

  First, a porous membrane (sample) containing an aromatic polysulfone resin stored at 25 ° C. is cut out to a length of 200 mm in the longitudinal direction, and a marked line is drawn at a position 150 mm from the end in the longitudinal direction of the sample. Next, the sample is allowed to stand in an autoclave and heated at a temperature of 121 ° C. under no tension for 30 minutes, then the sample after heating is transferred to a desiccator and cooled until the sample temperature reaches 25 ° C. The distance between the marked lines from the end of the sample after cooling is measured, and the thermal contraction rate is calculated by the following formula (S1). The samples are changed and tested three times, and their mean value is used.

[Production Method of Membrane Containing Aromatic Polysulfone Resin]
For the production of the membrane, known methods can be appropriately adopted. In the production of a porous membrane, for example, an aromatic polysulfone resin is dissolved in a solvent, the obtained solution is extruded into a predetermined shape, and dry-wet through an air gap or wet-solidify without an air gap. It may be introduced into a solution, phase separation and desolvation. Moreover, separately from this method, in the production of a porous membrane, an aromatic polysulfone resin is dissolved in a solvent, the obtained solution is cast on a substrate having a predetermined shape, and immersed in a coagulating solution to separate the phases. And desolvation.

  The nonporous membrane may be produced, for example, by melting the aromatic polysulfone resin and extruding it into a predetermined shape. In addition to this method, the nonporous membrane may be produced by melting the aromatic polysulfone resin and casting it on a substrate having a predetermined shape. In addition to this method, the nonporous membrane may be produced by dissolving an aromatic polysulfone resin in a solvent, casting this solution on a substrate of a predetermined shape, and removing the solvent.

  Moreover, when manufacturing a hollow fiber membrane as a porous membrane, the said solution is used as a spinning solution and a double annular nozzle is used. Specifically, the porous hollow fiber membrane is produced by discharging the solution from the outside and discharging a coagulating liquid (hereinafter sometimes referred to as "internal coagulating liquid") or gas from the inside. It is preferable to introduce these into the coagulating liquid (hereinafter sometimes referred to as "external coagulating liquid") via or without the air gap.

  As a good solvent (hereinafter sometimes referred to simply as “good solvent”) of the aromatic polysulfone resin used for the preparation of the solution, for example, N-methylpyrrolidone, N, N-dimethylformamide and N, N-dimethylacetamide Can be mentioned.

  Moreover, when manufacturing a porous membrane especially, you may make the said solution contain aromatic polyester resin, components other than a good solvent, and a swelling agent. Examples of components other than good solvents include hydrophilic polymers and poor solvents for aromatic polysulfone resins (hereinafter sometimes referred to simply as "poor solvents"). By including a hydrophilic polymer in the solution, it is possible to obtain a porous membrane which is excellent in water permeability and is suitably used for filtration such as ultrafiltration and precision filtration of aqueous fluid. When the solution does not contain a poor solvent or a swelling agent, it is preferable to use N, N-dimethylacetamide as a good solvent.

  Examples of hydrophilic polymers include polyvinyl pyrrolidone, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, polyvinyl alcohol, polyhydroxyalkyl (meth) acrylates such as polyhydroxyethyl acrylate and polyhydroxyethyl methacrylate, polyacrylamide and polyethylene imine Can be mentioned. Two or more hydrophilic polymers may be used as needed. Among them, polyvinyl pyrrolidone, particularly, high molecular weight polyvinyl pyrrolidone having a weight average molecular weight of 100,000 or more is preferable because the thickening effect of the solution can be enhanced even if the content is small.

  The amount of hydrophilic polymer used is, for example, 5 to 40 parts by weight, preferably 15 to 30 parts by weight, with respect to 100 parts by weight of the aromatic polysulfone resin. If the amount of hydrophilic polymer used is too small, the permeability of the resulting porous membrane will be insufficient, and if too large, the heat resistance, chemical resistance and toughness of the resulting porous membrane will be insufficient.

  Examples of the swelling agent include ethylene glycols such as ethylene glycol, diethylene glycol and triethylene glycol, and ethylene glycol is preferable because it is easy to remove.

  As the coagulating liquid, a poor solvent or a mixed solvent of a poor solvent and a good solvent can be used. It is preferable to use a mixed solvent of a poor solvent and a good solvent as the coagulating solution. By adjusting the mixing ratio of the poor solvent to the good solvent, the pore size and pore size distribution of the obtained porous membrane can be adjusted.

  When a hydrophilic polymer is contained in the solution to produce a porous membrane, the resulting porous membrane may be subjected to heat treatment or radiation treatment, as necessary. Thereby, the hydrophilic polymer in the porous membrane is insolubilized. By performing heat treatment or radiation treatment, the hydrophilic polymer is crosslinked and fixed in the porous membrane. Therefore, when using a porous membrane as a filtration membrane, it can control that a hydrophilic macromolecule elutes in a filtrate.

  The heat treatment or radiation treatment is preferably carried out under conditions that the porous membrane does not significantly change in shape, structure, mechanical properties, etc. and that the hydrophilic polymer crosslinks, either Only one process may be performed, or both processes may be performed.

  For example, the heat treatment of a porous film produced using polyvinyl pyrrolidone as a hydrophilic polymer is preferably performed at a treatment temperature of 150 to 190 ° C., and the treatment time is appropriately set according to the amount of polyvinyl pyrrolidone in the porous film. Ru.

  In addition, the radiation treatment of the porous film can be performed using α rays, β rays, γ rays, X rays or electron rays as radiation. In this case, damage to the porous membrane can be effectively suppressed by carrying out the porous membrane impregnated with the antioxidant-containing water.

  Furthermore, as described above, when producing a hollow fiber membrane as a porous membrane, the hollow fiber membrane may be subjected to steam sterilization treatment using an autoclave or the like.

  In addition, you may perform processes other than heat processing, a radiation process, and a steam sterilization process as a sterilization process for the obtained porous membrane. In the case where such a porous membrane is heated, if the heat shrinkage rate of the porous membrane is large, cracks may occur in the porous membrane due to the thermal shrinkage of the porous membrane.

  Further, the problem that a crack is generated in the porous film due to the thermal contraction of the porous film is a problem common to not only the porous film but also the flat film and the tubular film. Moreover, the above-mentioned subject is a common subject whether it is a single layer film or a multilayer film.

  Furthermore, even if the film is not treated as described above, the same problem is considered to occur when the film is heated at the time of production or use of the film.

  The film | membrane containing the aromatic polysulfone resin of this embodiment has a small heat contraction rate with respect to such a subject. Therefore, the occurrence of cracks in the film due to the thermal contraction of the film can be suppressed.

  According to this embodiment, an aromatic polysulfone resin and a film thereof that can obtain a film having a small thermal contraction rate can be obtained.

  Hereinafter, although the example of the present invention is shown, the present invention is not limited by this.

  In the present example, a porous membrane was used as an example of a membrane containing an aromatic polysulfone resin.

[Measurement of reduced viscosity]
1 g of aromatic polysulfone resin was dissolved in N, N-dimethylformamide to make its volume 1 dL, and the viscosity (η) of this solution was measured at 25 ° C. using an Ostwald-type viscosity tube. Moreover, the viscosity ((eta) ₀ ) of N, N- dimethylformamide which is a solvent was measured at 25 degreeC using Ostwald-type viscosity tube. Since the concentration of the solution is 1 g / dL, the value of the specific viscosity ((η−η ₀ ) / η ₀ ) is the value of the reduced viscosity in the unit dL / g.

[Measurement of tensile strength]
40 g of the resin obtained in Production Examples 1 to 5 and 160 g of N-methyl-2-pyrrolidone were stirred at 60 ° C. for 2 hours to obtain an aromatic polysulfone resin solution. Next, this solution was cast on a glass plate (thickness 3 mm) using a film applicator so that the film thickness after heat treatment was 30 μm. The resulting resin layer is heated at 80 ° C. in a high-temperature hot-air dryer to remove the solvent so that the amount of residual solvent in the resin layer is 10% by mass or less, and heat-treated at 250 ° C. under a nitrogen atmosphere. Thus, an aromatic polysulfone resin film was obtained.

  Using the obtained film, the tensile strength was measured based on ASTM D 882 by an autograph manufactured by Shimadzu Corporation. The test number was 5 times, and their average value was used.

[Measurement of heat shrinkage rate]

  First, a porous membrane (sample) stored at 25 ° C. was cut into a length of 200 mm in the longitudinal direction, and a marked line was drawn at a position of 150 mm from the end in the longitudinal direction of the sample. Next, the sample was allowed to stand in an autoclave and heated at a temperature of 121 ° C. for 30 minutes under no tension, and then the heated sample was transferred to a desiccator and cooled until the sample temperature reached 25 ° C. The distance between the marked lines from the end of the sample after cooling was measured, and the thermal contraction rate was calculated by the following formula (S1). The samples were changed and tested three times, and their average value was used.

<Production of aromatic polysulfone resin>
In the following production examples, a dichlorodiphenyl sulfone mixture in which 4,4′-dichlorodiphenyl sulfone and 3,4′-dichlorodiphenyl sulfone are mixed is used as the dihalogenosulfone compound.

  Moreover, the dihydroxy diphenyl sulfone mixture which mixed 4, 4'- dihydroxy diphenyl sulfone and 3, 4'- dihydroxy diphenyl sulfone was used as a dihydroxy sulfone compound.

  The ratio (m: n) of the molar content (m) of the repeating unit (I) to the molar content (n) of the repeating unit (II) in the aromatic polysulfone resin is calculated from the charge amount (mol) of the raw material monomer I asked. In addition, it was confirmed that all the used raw material monomers were consumed by the polymerization (polycondensation) reaction.

  The content of 3,4'-dichlorodiphenyl sulfone relative to the total mass of the dichlorodiphenyl sulfone mixture was determined by gas chromatography (GC) analysis under the following conditions. The content of 3,4'-dihydroxydiphenyl sulfone relative to the total mass of the dihydroxy diphenyl sulfone mixture was determined by GC analysis under the following conditions.

(conditions)
Sample: 1 μL of a solution of 0.1 g of a sample dissolved in 5 ml of acetone is injected Device: Agilent Gas Chromatograph Model 6850 Column: Agilent GC Column DB-5 (inner diameter: 0.25 mm, length: 30 m, film thickness: 1 μm) )
Column temperature: 290 ° C
Detector: Hydrogen flame ionization type

[Measurement of Content of 3,4'-Dichlorodiphenyl Sulfone]
In the spectrum obtained, the sum of the peak areas detected after the retention time of 15 minutes is 100, and the peak area detected at the retention times of 15.4 minutes to 15.7 minutes is determined by the area percentage method, and the dichlorodiphenylsulfone mixture The content of 3,4'-dichlorodiphenyl sulfone relative to the total mass of

[Measurement of Content of 3,4′-Dihydroxy Diphenyl Sulfone]
In the spectrum obtained, the sum of peak areas detected after the retention time of 14 minutes is 100, and the peak area detected at the retention time of 14.5 minutes to 14.8 minutes is determined by the area percentage method, and the dihydroxydiphenylsulfone mixture The content of 3,4′-dihydroxydiphenyl sulfone relative to the total mass of

Production Example 1
Containing 4,4'-dihydroxydiphenyl sulfone (3,4'-dihydroxydiphenyl sulfone) in a 500 mL polymerization tank equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser with a receiver at the tip. Amount: 0% by mass 100.1g, 4,4'-dichlorodiphenylsulfone (content of 3,4'-dichlorodiphenylsulfone: 0.1% by mass) 117.7 g, and 193.6 g of diphenyl sulfone as a polymerization solvent The reaction mixture was heated to 180.degree. C. while flowing nitrogen gas into the system. After 56.5 g of potassium carbonate was added to the obtained solution, the temperature was gradually raised to 290 ° C., and reaction was performed at 290 ° C. for further 4 hours.
The resulting reaction solution was then cooled to room temperature to solidify the reaction product. The solid was taken out and finely ground, and the ground solid was washed with warm water and washed with a mixed solvent of acetone and methanol several times. Furthermore, the solid after washing was heated and dried at 150 ° C. to obtain a white powder of an aromatic polysulfone resin.

  The reduced viscosity of the aromatic polysulfone resin was 0.60 (dL / g). The ratio (m: n) in the aromatic polysulfone resin was 1: 1000.

Production Example 2
An aromatic polysulfone resin was obtained in the same manner as in Production Example 1 except that the content of 3,4'-dichlorodiphenylsulfone relative to the total amount of the dichlorodiphenylsulfone mixture was changed to 0.3% by mass.

  The reduced viscosity of the aromatic polysulfone resin was 0.60 (dL / g). The ratio (m: n) in the aromatic polysulfone resin was 1: 333.

[Production Example 3]
An aromatic polysulfone resin was obtained in the same manner as in Production Example 1 except that the content of 3,4'-dichlorodiphenylsulfone relative to the total amount of the dichlorodiphenylsulfone mixture was changed to 0% by mass.

  The reduced viscosity of the aromatic polysulfone resin was 0.60 (dL / g). The ratio (m: n) in the aromatic polysulfone resin was 0: 100.

Production Example 4
An aromatic polysulfone resin was obtained in the same manner as in Production Example 1 except that the content of 3,4'-dichlorodiphenylsulfone relative to the total amount of the dichlorodiphenylsulfone mixture was changed to 0.7% by mass.

  The reduced viscosity of the aromatic polysulfone resin was 0.60 (dL / g). The ratio (m: n) in the aromatic polysulfone resin was 1: 143.

Production Example 5
An aromatic polysulfone resin was obtained in the same manner as in Production Example 1 except that the content of 3,4'-dichlorodiphenylsulfone relative to the total amount of the dichlorodiphenylsulfone mixture was changed to 1.0% by mass.

  The reduced viscosity of the aromatic polysulfone resin was 0.60 (dL / g). The ratio (m: n) in the aromatic polysulfone resin was 1: 100.

<Production of Porous Membrane Containing Aromatic Polysulfone Resin>
Example 1
In a 500 mL separable flask, 40 g of the aromatic polysulfone resin obtained in Preparation Example 1, 120 g of polyethylene glycol 400 and 140 g of N-methyl-2-pyrrolidone are added, and stirred at 60 ° C. for 2 hours to obtain a pale yellow aromatic polysulfone. A resin solution was obtained. This solution is coated on a 3 mm thick glass plate using a film applicator so that the thickness of the resin layer before drying is 300 μm, and immediately after coating, the glass plate is immersed in water, and then from the glass plate The peeled coating was allowed to stand in water for 30 minutes. Next, this coating film was dried overnight at 50 ° C. using a high-temperature hot-air dryer to obtain a porous film containing an aromatic polysulfone resin.

Example 2
A porous film containing an aromatic polysulfone resin was obtained in the same manner as in Example 1 except that the aromatic polysulfone resin obtained in Production Example 2 was used.

Comparative Example 1
A porous film containing an aromatic polysulfone resin was obtained in the same manner as in Example 1 except that the aromatic polysulfone resin obtained in Production Example 3 was used.

Comparative Example 2
A porous film containing an aromatic polysulfone resin was obtained in the same manner as in Example 1 except that the aromatic polysulfone resin obtained in Production Example 4 was used.

Comparative Example 3
A porous film containing an aromatic polysulfone resin was obtained in the same manner as in Example 1 except that the aromatic polysulfone resin obtained in Production Example 5 was used.

  The reduced viscosities, the ratios (m: n) and the tensile strengths of the aromatic polysulfone resins of Examples 1 and 2 and Comparative Examples 1 to 3 and the thermal shrinkage of the porous membrane are shown in Table 1.

  The tensile strengths of the aromatic polysulfone resins of Example 1 and Example 2 to which one aspect of the present invention is applied were similar to those of the aromatic polysulfone resins of Comparative Examples 1 to 3. On the other hand, the thermal contraction rates of the porous membranes of Example 1 and Example 2 were smaller than the thermal contraction rates of the porous membranes of Comparative Examples 1 to 3.

  From the above results, it was confirmed that the present invention is useful.

Claims (3)

It has a repeating unit represented by following formula (I) and Formula (II), The molar content (m) of the repeating unit represented by said Formula (I), The repeating represented by said Formula (II) Aromatic polysulfone resin in which the ratio (m: n) to the molar content (n) of the unit is 1: 2000 to 1: 200.

(The hydrogen atoms in the phenylene group of the above formula (I) and formula (II) may be each independently substituted with an alkyl group, an aryl group or a halogen atom.)   A membrane comprising the aromatic polysulfone resin according to claim 1.   The membrane according to claim 2, which is a porous membrane.