JPS61133106A - Preparation of separating membrane - Google Patents

Abstract

PURPOSE:To prepare hollow yarn for gas separation having superior permeability and selectivity for gaseous CO2 by using arom. polyimide obtd. by imidating a polymer prepd. by polycondensing equimolar amt. of arom. tetracarboxylic acid and arom. diamine. CONSTITUTION:A doping liquid is prepd. by dissolving uniformly 7-30wt% arom. polyimide contg. at least 70% recurrent unit expressed by the formula (I) and (II) in a solvent consisting primarily of a phenolic compound. Preferred phenolic compd. is phenol, cresol, xylenol, halogenated phenol, etc., and necessary content thereof is ca.60vol%. Aq. soln. contg. ca.60vol% alcohol or acetone is used as the coagulating liquid for the formation of film by the wet process. Such coagulating liquid is used for performing coagulation at relatively lower temp. (-10-60 deg.C).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to methane, nitrogen, -carbon oxide, argon, In order to separate and concentrate mixed gases such as ethane into each gas component, we use asymmetric separation membranes (including hollow fibers) made of aromatic polyimide for gas separation that exhibit extremely excellent performance. It relates to a method of producing a film from a specific resin solution (dope solution) using a wet film forming method under specific coagulation conditions.

[Description of known technology]

Conventionally, solutions of phenolic compounds of aromatic polyimide (
Examples of methods for manufacturing aromatic polyimide semipermeable membranes or hollow fibers from a dope solution using a wet film forming method include those described in JP-A-56-21602 and JP-A-56-157435. The method was known.

However, the aromatic polyimide separation membranes described in those known documents only specifically disclose the case where, for example, a mixed gas of hydrogen and carbon monoxide is used, and furthermore, the aromatic polyimide separation membrane described in those known documents is only disclosed for the case where a mixed gas of hydrogen and carbon monoxide is used. No gas separation materials with excellent performance have been described, and aromatic polyimide separation membranes or hollow fibers with high selectivity and permeation rates for other gas mixtures (e.g., carbon dioxide-containing gas mixtures) have not been described. A method to do so was expected.

[Requirements and effects of the present invention"]

As a result of intensive research into a method for producing aromatic polyimide separation membranes or hollow fibers that have excellent permeability to mixed gases containing carbon dioxide, the inventors discovered that biphenyl tetra Both components in approximately equimolar amounts, consisting of an aromatic tetracarboxylic acid component mainly containing carboxylic acids, and an aromatic diamine component containing about 50 mol% or more of an aromatic diamine having -802-. A specific aromatic polyimide obtained by polymerization is dissolved in a phenolic compound, and the solution is used as a dope solution, and the 1ill!
A wet method in which the i-film is coagulated with an aqueous solution (coagulation liquid) containing a high concentration of alcohols or acetones.
The single membrane method has excellent permeation rates for carbon dioxide gas, as well as excellent separation (selectivity) of carbon dioxide gas from other small molecular gas components (e.g. methane, nitrogen, carbon oxide, argon, ethane, etc.). We discovered that it is possible to produce separation membranes or hollow fibers made of aromatic polyimide that have extremely excellent gas separation performance, such as excellent permeability.
completed this invention.

That is, the present invention provides an aromatic tetracarboxylic acid component containing biphenyltetracarboxylic acids in a proportion of about 70 mol% or more based on the total acid component, and an aromatic tetracarboxylic acid component containing a -5o2- divalent group in the molecule. A soluble aromatic polyimide obtained by polymerizing and imidizing diamine and an aromatic diamine component containing approximately 50 mol% or more of the total diamine component in approximately equimolar amounts is dissolved in a phenolic compound. A thin film (including hollow fibers) is formed from the dope by using the resin solution as a dope for membrane formation (also meant for spinning hollow fibers), and adding 60 volumes of alcohol or acetone. Aqueous solution containing % or more (coagulation liquid)
The present invention relates to a method for producing an asymmetric separation membrane (particularly a gas separation membrane), which is characterized by solidifying a thin film of the dope liquid.

In this invention, as described above, a diamine component containing 50 mol % or more of an aromatic diamine having -802- in its molecule is used as the aromatic diamine component, and A soluble aromatic polyimide obtained by polymerization and imidization is used as a polymer component of the dope liquid together with a carboxylic acid component, and an aqueous solution containing a high concentration of alcohols or acetones is used as a coagulating liquid. It is particularly distinctive that

The aromatic polyimide separation membrane or hollow fiber membrane obtained by the production method of the present invention is a separation membrane that has a high permeation rate for carbon dioxide gas, oxygen, etc., and a high degree of separation from methane, nitrogen, etc. , carbon dioxide permeation rate (PC
O2] is about lXl0-5cd/-・sec -co+
Hg or more, and the ratio of carbon dioxide gas permeation rate to methane permeation rate (also referred to as PCO2/PCH4i permselectivity) is about 20 or more, which is an asymmetric separation membrane having excellent gas separation performance.

Further, since the separation membrane obtained by the production method of the present invention is made of a specific aromatic polyimide, it has extremely excellent heat resistance, mechanical strength, chemical resistance, etc.

C Detailed explanation of each requirement of the present invention] In this invention, aromatic polyimide is a polymer obtained by polymerization and imidization from two types of heptamer components in which the acid component and the diamine component are both aromatic compounds. It is a heat-resistant polymer having an imidization rate of about 90% or more, which will be described later.

The imidization rate in Section H is a value measured and calculated by infrared absorption spectrum analysis, and is the proportion of bonds that are imide bonds among all bonds that can be imide bonds in the polymer chain of a polyimide polymer. Percentage (%)
This is shown in .

The aromatic polyimide used in the production method of the present invention contains biphenyltetracarboxylic acids in a proportion of about 70 mol% or more, preferably 8 mol% or more, particularly preferably 90 to 100%, based on the total acid components. The aromatic tetracarboxylic acid component contained in
The aromatic diamine component containing at least mol%, preferably at least 60 mol%, particularly preferably from 80 to 100 mol%, is polymerized and imidized in approximately equal moles. An aromatic polyimide.

That is, the aromatic polyimide used in this invention is
A repeating unit represented by the general formula (wherein R1 is a divalent residue obtained by removing the amino group from an aromatic diamine j having a divalent rSO2- group in the molecule), and A repeating unit represented by the general formula (wherein R2 is a divalent residue obtained by removing the amino group from an aromatic diamine j that does not have an r-so2- divalent group in the molecule) It is an aromatic polyimide 1 which is soluble mainly in organic polar solvents.

In addition to the repeating units represented by the general formulas (() and (Ill), the above-mentioned aromatic polyimide also has a repeating unit represented by the general formula (A), which is a tetracarboxylic acid based on an aromatic tetracarboxylic acid different from the biphenyltetracarboxylic acids. is a residue of valence,
R1 has the same meaning as in the general formula (r) above), and a repeating unit represented by the general formula (wherein, A has the same meaning as in the general formula (III)), and R2 has the same meaning as in the general formula (III) above; It may further have a repeating unit having the same meaning as in II).

In the aromatic polyimide used in this invention, if the proportion of biphenyltetracarboxylic acids in the aromatic tetracarboxylic acid component is too small, the general formulas [I] and (II
) is produced, and such aromatic polyimides do not dissolve easily in organic solvents, or tend to precipitate (unstable) even when dissolved in solvents. In addition, if the proportion of aromatic diamine j having an r-3O2- divalent group in the molecule in the aromatic diamine component is too small, An aromatic polyimide having a low proportion of repeating units represented by formulas (1) and [■] is produced,
When an asymmetric separation membrane is formed from such an aromatic polyimide dope solution, the gas permeation rate of the asymmetric membrane for carbon dioxide gas etc. becomes slow, or each gas mixture containing carbon dioxide gas etc. Degree of separation into components (selectivity)
is not appropriate as it will be low.

The above-mentioned aromatic polyimide was measured at a temperature of SO ℃, and the polymer concentration of the sample was 0.5 g / 100 ml! The logarithmic viscosity measured under measurement conditions using a solvent (a mixed solvent of 4 volumes of parachlorophenol and 1 volume of orthochlorophenol) is about 0.3 to 7.0, particularly 0.4 to 5°0, more preferably can be used in a wide range of values, ranging from about 0.5 to 4.0.

The above-mentioned aromatic polyimide preferably contains 50 mol% or more of aromatic diamine 1 having a divalent r-SO2- group represented by the general formula R2N-Rt-NHz (V) in its molecule. is 60-10
Contains 0 mol% and has the general formula R2N-R2-NR
An aromatic diamine component containing 50 mol% or less, preferably 0 to 40 mol%, of an aromatic diamine that does not have an r-so2- divalent group represented by 2(VI) in its molecule;
An aromatic tetracarboxylic acid component containing 70 mol% or more, especially 80 mol% or more of biphenyltetracarboxylic acids is used in an organic polar solvent (e.g., phenolic compound, halodanated phenol solvent). )in,
Polymerization and imidization reaction (imide cyclization reaction) in one step at a reaction temperature of about 120~4QQ℃, especially 150~SO0℃
It can be manufactured by

In the one-step polyimide production method described above, a solution (dope solution) of a phenolic compound of aromatic polyimide that can be used in the method of the present invention is directly obtained, and the reaction mixture is directly passed through a separation membrane. It is optimal because it can be used as a dope for film formation or hollow fiber spinning.

Further, as a method for producing the aromatic polyimide used in the method of the present invention, for example, the above-mentioned biphenyltetracarboxylic acid component and aromatic diamine component are combined with N
-Dissolve approximately equimolar amounts in an organic polar solvent such as methylpyrrolidone, pyridine, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, phenol, or cresol, and
Polymerizes at a temperature of 0°C or less, especially 0 to 60°C, and has a logarithmic viscosity (SO°C, concentration: 0.5 g/100s + fN-methylpyrrolidone) of about 0.3 or more, especially about 0.5 to 7. A polyamic acid is produced, and a solution of the polyamic acid in an organic polar solvent (the polymerization reaction solution may be used as it is) is added with a tertiary amine compound such as trimethylamine, triethylamine, or pyridine, acetic anhydride, thionyl chloride, or carbodiimide. Add an imidization accelerator such as
The polyamic acid solution was imidized at 150°C, or the polyamic acid solution was heated to 100°C without adding an imidization promoter.
Heating to ~400°C, preferably 120~SO0°C,
It can be obtained by imidizing the polymer to an imidization rate of 90% or more, and precipitating and isolating a powdery aromatic polyimide.

Furthermore, as a method for producing aromatic polyimide, a large amount of acetone or alcohol is added to a solution of polyamic acid having a logarithmic viscosity of about 0.5 or more produced in the same manner as described above to precipitate polyamic acid powder. Alternatively, while removing the solvent by evaporation from the polyamic acid solution, if necessary, add a precipitant etc. to precipitate the polyamic acid powder, and isolate it by filtration etc. is heated to a high temperature of 150 to 400℃,
A method of producing polyimide powder by imidizing the polymer until the imidization rate becomes 90% or more can be mentioned.

Examples of aromatic diamines represented by the general formula (V) include those represented by the general formula (wherein R is a hydrogen atom or a lower alkyl group such as a methyl group, an ethyl group, or a propyl group). diaminodiphenylsulfone, or with the general formula (wherein R' is a hydrogen atom, a lower alkyl group such as a methyl group, an ethyl group, a propyl group, or an alkoxy group such as a methoxy group or an ethoxy group); Examples include diaminodiphenylene sulfone shown below.

The diamino-diphenyl sulfone represented by the general formula [■] includes 4.4'-diamino-diphenyl sulfone, 4.41-diamino-3,3'-dimethyl-diphenyl sulfone, and 3.3'-diamino-diphenyl sulfone. -diphenylsulfone, 3,4'-diamino-Schiff λnylsulfone, etc. Also, examples of the diamino-diphenylene sulfone represented by the general formula [■] include 3,7-diamitwo-2,8-dimethyl - Diphenylene sulfone, 3,7
-Diamitsu z, 8-diethyl-diphenylene sulfone, 3,7-diamizu 2,8-dipropyl-diphenylene sulfone, 2,8-diamino-3,7-dimethyl-diphenylene sulfone, 3,7-diamizu 2 Examples include .8-dimethoxy-diphenylene sulfone.

Examples of the aromatic diamine represented by the general formula (Vl) include 4.4''-diaminodiphenyl ether,
Diphenyl ether compounds such as 3,3°-dimethyl-4,4°-diaminodiphenyl ether, 3.3′-dimethoxy-4,4°-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, and 3,3”-diaminodiphenyl ether , 4,4′-diaminodiphenylmethane, diphenylmethane compounds such as 3,3′-diaminodiphenylmethane, 4,4″-diaminobenzophenone, 3,3′-diaminobenzophenone, 3.
benzophenone compounds such as 4'-diaminobenzophenone; 2.2-bis(phenyl)propane compounds such as 2.2-bis(3-aminophenyl)propane and 2.2-bis(4-aminophenyl)propane; Benzidine-based compounds such as 3,3゛-dimethylbenzidine, 3゜3''-dimethoxybenzidine, etc.
-phenylenediamine, 3,5-diaminobenzoic acid, and the like.

Examples of the above-mentioned biphenyltetracarboxylic acids include 3,3°, 4,4"-biphenyltetracarboxylic acid or its acid dianhydride, 2,3.3", 4°-biphenyltetracarboxylic acid or its acid dianhydride, Examples include anhydrides, lower alcohol esters or phenyl esters thereof, and mixtures thereof.

Further, in this invention, the aromatic tetracarboxylic acid component is
In addition to the aforementioned biphenyltetracarboxylic acids, other tetracarboxylic acid components such as pyromellitic acid, 3,3
°, 4,4°-benzophenonetetracarboxylic acid, 2,
2-bis(3,4-dicarboxyphenyl)propane,
Bis(3,4-dicarboxyphenyl)sulfone, bis(3,4-dicarboxyphenyl)ether, bis(3
, 4-dicarboxyphenyl)thioether, or aliphatic tetracarboxylic acids such as butanetetracarboxylic acid, or their dianhydrides, salts, or esterified derivatives. It may be contained in a proportion of SO mol % or less, particularly 20 mol % or less, based on the tetracarboxylic acid component.

The dope solution used in the method of the present invention is such that the aromatic polyimide having at least 70% of the repeating units represented by the above-mentioned general formulas (1) and (II) is dissolved in a solvent containing a phenolic compound as a main component. It is a uniformly dissolved solution, and the concentration of the aromatic polyimide in the dope solution is preferably about 7 to about 7% by weight of SO, particularly about 10 to 25% by weight, and more preferably about 12 to 20% by weight. If the concentration is too low below the lower limit, the shape of the obtained separation membrane (hollow fiber membrane) will become non-uniform, and the selective separation performance between carbon dioxide gas and methane will decrease, which is undesirable. If the concentration becomes too high above the upper limit of , the amount obtained is NIII! ! This is not preferable because the permeation rate of carbon dioxide gas (hollow fiber membrane) tends to decrease.

The solvent in which the aromatic polyimide is dissolved in the method of this invention may be any solvent containing a phenol compound as a main component, and the phenol compound may be 100% by volume.
In addition to the phenolic compound, other solvents that are compatible with the phenolic compound, such as carbon disulfide, dichloromethane, trichloromethane, nitrobenzene, 0-dichlorobenzene, etc., are preferred. It may be a mixed solvent containing at most 20% by volume, more preferably at most 10% by volume.

The above-mentioned phenolic compound has a melting point of about 100°C.
Hereinafter, phenolic compounds whose temperature is particularly preferably 80°C or lower and whose boiling point is about SO0°C or lower at normal pressure, particularly preferably 280°C or lower, such as phenol, 0-, t-, or p-cresol, are preferred. , 3,5-xylenol, or a halogenated phenol obtained by replacing the hydrogen in the benzene ring of the -valent phenol with a halogen.

The above-mentioned halogenated phenol is represented by the general formula (wherein R'' is hydrogen or an alkyl group having 1 to 3 carbon atoms, and X is a halogen), and has a melting point of about 100°C or less. A halogenated phenol having a boiling point of about SO0° C. or lower at normal pressure is optimal because it melts the biphenyltetracarboxylic acid-based aromatic polyimide uniformly and well.

Examples of the halogenated phenol compounds include:
3-chlorophenol, 4-chlorophenol (sometimes abbreviated as para-chlorophenol, PCP), 3
-bromophenol, 4-bromophenol, 2-chloro-4-hydroxytoluene, 2-chloro-5-hydroxytoluene, 3-chloro-6-hydroxytoluene,
4-chloro-2-hydroxytoluene, 2-bromo-4
Examples include -hydroxytoluene, 2-bromo-4-hydroxytoluene, 2-bromo-5-hydroxytoluene, 3-bromo-6-hydroxytoluene, and 4-bromo-2-hydroxytoluene.

In the method of the present invention, as described in the above-mentioned method for producing aromatic polyimide, a biphenyltetracarboxylic acid component and an aromatic diamine component are polymerized in one step at 120 to 400°C in a melted solution of a phenolic compound. When producing aromatic polyimide by imidization, the polymerization reaction solution can be immediately used for separation membrane production or hollow fiber spinning by simply adjusting the polyimide concentration or solution viscosity as necessary. It can be used as a resin solution (dope solution) of aromatic polyimide.

However, in the production of aromatic polyimide, when the polyimide is isolated as a powder, the dope solution used in this invention is a mixture of the polyimide powder in a solvent mainly containing a phenolic compound. - Adjustment can be made by dispersing, mixing, and heating the dispersion liquid to completely melt the polyimide powder.

In this invention, the dope liquid for film forming is the dope liquid used when extruding a thin film-like body (hollow fiber-like body) of the dope liquid from a nozzle for forming a thin film (hollow fiber) (for spinning). A uniform liquid solution composition having a rotational viscosity of at least 500 centipoise, particularly about 10 to 100,000 poise at a temperature of "about 20 to 150 °C, particularly in the temperature range of SO to 120 °C", It is preferable that a thin film (hollow fiber) can be easily extruded (spun) from the nozzle.

In the method of this invention, the above-mentioned phenolic compound solution of aromatic polyimide is used as a dope solution for film formation (for hollow fibers), and the dope solution is extruded from a nozzle for hollow fibers to form an unsolidified thin film. Comparison consisting of an aqueous solution containing alcohols or acetones at a ratio of 60% by volume or more, preferably 65 to 100% by volume. An asymmetric separation membrane made of polyimide (
hollow fibers) are manufactured continuously.

The unsolidified hollow fibers formed as described above are extruded into -10 to 60°C, particularly -5 to 60°C.
It is appropriate to coagulate the fiber by immersing it in the above-mentioned coagulating solution at 50° C. (semi-wet film forming method) and then spin the hollow fiber.

Examples of alcohols used in the coagulation liquid include lower alcohols such as methanol, ethanol, and propyl alcohol, and examples of acetones include ketone compounds having a lower alkyl group such as acetone, diethyl ketone, and methyl ethyl ketone. can be mentioned.

In the method of this invention, the hollow fiber nozzle for forming the hollow fibers of the aromatic polyimide resin solution (dope solution) can be formed by extruding the hollow fibers from the F-polymer solution of the polymer solution. Any type of hollow fiber nozzle may be used, such as a tube-in-orifice nozzle.
type), segmented/de-arc type nozzle (
segwented arc type). In this invention, a tube-in-orifice type nozzle is suitable as the hollow fiber nozzle. This tube-in-orifice type nozzle is
As shown in Figure 3, a tube 3 (outer diameter 0.15-1.6 mm, inner diameter 0
．． 05 to 1.4 mm) protrudes, and the dope liquid 16 is pushed out by back pressure from the gap (annular part) between the opening inner circumferential surface of the orifice 2 and the outer circumferential surface of the tube 3. A gas or liquid (also referred to as core liquid) 20 is supplied from the inner hole to form a hollow fiber body.

In the method of this invention, the hollow fibers are formed from the resin solution (dope solution) by, for example, filtering and defoaming the dope solution at about 20 to 200°C, especially SO to 150°C to form the hollow fibers. It is supplied to a nozzle head tank having a nozzle for yarn, and the dope liquid in the sod tank is fed to the nozzle with about 0.1~
Approximately 20 ksr/cd, especially 0.2 to 10 kg/cd (gauge pressure) of back pressure is applied, and about 20 ksr/cd is applied from the hollow fiber nozzle.
A method may be mentioned in which the dope is extruded at a discharge temperature of ~150°C, particularly SO ~120°C, to form hollow fibers of the dope.

In the method of the present invention, when extruding the hollow fiber, gas or liquid (core liquid) is introduced from the tube inside the hollow fiber nozzle into the hollow fiber that is being extruded.
Spinning is carried out while supplying.

In this invention, immediately after extruding a hollow fiber from a hollow fiber nozzle as described above, the uncoagulated hollow fiber is stretched under tension and placed in a coagulation liquid while being slightly stretched by a tensile force. It is preferable to immerse it in water and solidify it.

In addition, in this invention, after the hollow filament is coagulated in a coagulation liquid to an extent that the hollow fiber state can be maintained, the hollow filament is wound around a guide roll, a tension roll, etc., and the direction of the hollow filament is After some conversion, it is sent to the next process.

In this invention, the hollow filament which has been partially coagulated (-secondary coagulation) in the first coagulation bath as described above is further coagulated in the second coagulation bath.
In the second coagulation bath, the hollow fibers are immersed in the coagulation solution multiple times to substantially extract and remove the solvent (phenolic compounds, etc.) remaining in the tube wall of the hollow fibers, and coagulate them ( Secondary solidification) is preferred.

In the method for manufacturing a separation membrane made of hollow fibers described above,
- When performing secondary coagulation and secondary coagulation, at least the first primary coagulation liquid (the dope liquid is extruded from a membrane forming nozzle in the form of a hollow fiber and comes into contact with it to temporarily coagulate the hollow fiber) The coagulating liquid) must contain alcohols or acetones at least 60% by volume, preferably at least 65% by volume, and then the secondary coagulating liquid with which the temporarily coagulated hollow fibers should contain alcohols or acetones. It is sufficient to contain acetone in an amount of 50% by volume or more, particularly about 55 to 90% by volume.

Further, in the present invention, when performing the above-mentioned primary coagulation and secondary coagulation, if the secondary coagulation liquid is an aqueous solution containing alcohols in the above concentration range, the secondary coagulation liquid is acetone. Or, conversely, if the secondary coagulation liquid is an acetone aqueous solution, the secondary coagulation liquid is an alcohol aqueous solution.
Separation IiJ with excellent gas separation properties! (Hollow fiber membrane) is obtained.

Furthermore, the hollow fibers formed as described above can be stored by immersing them in an inert solvent, such as water, or by drying them by an appropriate method after thoroughly washing them with an inert solvent. I can do it.

The method of the present invention can be applied, for example, to the first Ig! An asymmetric separation membrane (hollow fiber) can be manufactured using a spinning device as shown in J.

That is, as shown in FIG. 1, a dope liquid 16 of an aromatic polyimide solution is supplied to the spinning nozzle head 1 having a tube-in-orifice type nozzle, and the dope liquid is injected from the nitrogen gas line 15. Add back pressure (approximately 0.1 to 20-/-) using nitrogen gas, etc., and apply approximately 20 to 150
The dope solution is heated to a discharge temperature of ℃, and a core gas (nitrogen gas, etc.)
0, while extruding the dope liquid into a hollow fiber shape from the annular gap between the inner peripheral surface of the orifice 2 of the hollow fiber nozzle and the outer peripheral surface of the tube 3, forming a hollow fiber-like body 4 of the dope liquid, While applying a tensile force to the hollow filament 4 and stretching it, it is immersed in the coagulation liquid 17 in the first coagulation tank 6 to temporarily solidify it, and then the hollow filament 4 is placed on the guide roll 5.7. It is wound and supplied to the second coagulation tank 11 filled with the coagulation liquid 18, and is wound around a pair of rolls 8.9 installed inside the coagulation tank 11, and is reciprocated between the rolls to solidify. The hollow fibers are immersed in the solution multiple times to cause secondary solidification, and finally the solidified hollow fibers are supplied to a storage tank 13 filled with an inert solvent 19 for storage and stored.

Note that any of the guide roll 5.7, the pair of rolls 8.9 of the second coagulation tank 11, the guide roll 12, etc.
It may also be connected to a drive motor and act as a pulling roll. The speed at which the hollow fibers are taken up by the tension roll is preferably about 1 to loom/min, particularly about 2 to 80 m/min.

The polyimide hollow fibers produced by the method of the present invention have excellent chemical resistance, heat resistance, mechanical strength, etc., and in particular, in terms of gas separation performance, they have excellent permselectivity (PC) between carbon dioxide and methane.
O2/PCl4) is about 20 or more, especially about SO~10
It is as high as about 0, and the carbon dioxide gas permeation rate (PCO2> is about I x 10-5ctl/cd・sec・ai
This is an excellent hollow fiber for gas separation that exhibits Hg or higher.

Reference Examples 1 to 11 3.3″, 4.4′ to biphenyltetracarboxylic dianhydride (s-BPDA) 80av+ol, and the first
The aromatic diamine compound of the type and amount shown in the table (80+ smol with a compound needle) was placed together with parachlorophenol (solvent) in a separable flask equipped with a stirrer and a nitrogen gas introduction tube, and the mixture was heated to room temperature while flowing nitrogen gas. From 180
The temperature was raised to 180° C. over about 1 hour, and polymerization was carried out at 180° C. for the reaction time shown in Table 1. The results are shown in Table 1.

In each reference example, parachlorophenol was added together with each monomer component so that the polymer concentration was as shown in Table 1.

Reference Examples 12 to 13 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) 200 w+sol,
4.4'-diaminodiphenylsulfone (p-OAOS
) 200+*sol and 8005aol of p-hydroxybenzoic acid were placed together with parachlorophenol in a separable flask equipped with a stirrer and a nitrogen gas introduction tube, and heated from room temperature to 180°C for about 1 hour while flowing nitrogen gas. The temperature was raised at 180° C. for 40 hours to carry out polymerization and imidization reactions. This polymerization solution was dropped into ethanol to precipitate the polymer, which was then filtered, separated, washed, and dried to recover the aromatic polyimide.

The obtained aromatic polyimide powder was added to parachlorophenol and heated to give the polymer concentration shown in Table 1 (Reference Example 12: 20% by weight, or Reference Example 13: SO weight%). A resin solution (dope solution) was prepared by dissolving it, and its properties are shown in Table 1.

Reference Example 14 3. instead of 4.4”-diaminodiphenylsulfone.
A dope solution was prepared in the same manner as in Reference Example 2 except that 3'-diaminodiphenylsulfone (a-OAOS) was used. Its properties are shown in Table 1.

Reference Examples 15 to 16 4,4°-diaminodiphenyl ether (DADE) was used instead of the diamino-dimethyl-diphenylene sulfone isomer mixture, and the polymerization time was changed to 5 hours (Reference Example 15). Instead, 4,4'-diaminodiphenyl ether (DADB) 6401@01
and using 5 mmol of 1,3-diaminobenzoic acid,
A dope solution was prepared in the same manner as in Reference Example 1, except that the polymerization time was changed to 10 hours (Reference Example 16).

Table 1 shows the properties of these dope solutions.

In Table 1, the abbreviations in the aromatic diamine column are as follows:
They are as follows.

DDMDS, diamino-dimethyl-diphenylenesulfone isomer mixture [3,7-diamitwo-2.8-dimethyl-diphenylenesulfone 5 mol%, 3,7-diamitwo-2,6-dimethyl-diphenylene sulfone: 23 mol% , and 3,7-diamitwo-4,6-dimethyl-diphenylenesulfone: 2 mol %] LoloEDS, diamino-diethyl-diphenylenesulfone isomer mixture [3,7-diamitwo-2,8-diethyl-diphenylenesulfone: 73 mol%, 3,7-diamitou-2,6-dinity-diphenylenesulfone: 24 mol%, and 3,7-diamitou-4,6-dinity-diphenylenesulfone: 3 mol%] p-ro AI) S, 4,4'-diaminodiphenylsulfone a-DADS; 3.3°-diaminodiphenylsulfone BAPS i 4,4'-bis(p-aminophenoxy)diphenylsulfone DADE; 4,4'-diaminodiphenyl ether DADMB i4, 4°-quaminobibenzyl DABA; 1,3-diaminobenzoic acid DAP
;2,6-cyamitsubiridine See Table 1 Aromatic diamyl y9 Polymerization time Properties of polymer Properties of dope liquid
Imidized logarithmic polymer turbidity rotational viscosity example
-1) Viscosity
(ii1%) (Boas) ID Kaida (fund)
26.5 >90% 1.4 15.0
SO002D[M)S80 20
．． 0 - 0.9 25.0 20003
F2DADE8 20.0 - 1.
3 15.0 250040DMOS72DAD
f! 8 13.0 °-1,220,01
7005 Rabbit I Training Button Group Jun SO. Oda 1
．． 2 15.0 150060011 Return Gen 1
6 21.5 〃1.3 15. Q
20QQ7 DIM)S32 DDEDS32
DADE16 19.0' 1.5
15.0 400080IM)S64BAPS16
55.0' 1.2 15.
0 15009DDMDS64DABA16
29.0 ” 1.3 15=0
150010DIM reply DAP 16
6.5 - 1.2 15.0 1400
11DDEO38022,0#1.4 12.0
250012p-OAO320040,0〃1.0
2G, 0 80013p-OAO320040
,0#1.1 SO. 0 500014a-DA
IE200 40.0'
0.3 2Q, 0 SOQ15DAD880
5.0 #1.4
15.0 SO0016DADE64DABA16
10.0 #1.2 15.0
2000 Examples 1 to 42 and Comparative Examples 1 to 7 As shown in Table 2, the polymerization reaction solution prepared in each Reference Example 1 to 16 was used as a dope solution to form the hollow space shown in FIG. Aromatic polyimide hollow fibers were spun using a yarn spinning device.

First, each dope solution 16 was supplied to a nozzle head 1 for spinning hollow fibers having a tube-in-orifice type nozzle as shown in FIG. The hollow fiber nozzle for the nozzle head 1 has an orifice 2 with an inner diameter of 1.0 m opened in the center of the bottom surface of the head 1.
The outer diameter is 0.6 m, and the inner diameter is 0.6 m.
This is a tube-in-orifice type nozzle in which a tube 3 of 3 tm is provided protrudingly.

As shown in FIG. 1, the dope liquid 16 inside the nozzle head 1
, apply a back pressure of nitrogen gas from the nitrogen gas supply conduit 15 to an appropriate pressure within the range of 2 to 5 kg/d, and
The discharge temperature when discharging the dope liquid from the hollow fiber nozzle is heated to an optimal temperature within the range of approximately SO to 80°C, and nitrogen gas is heated from inside the tube 3 of the hollow fiber nozzle. While supplying (core gas), extrude the dope liquid from the hollow fiber nozzle to form a hollow fiber body of the dope liquid,
Subsequently, the hollow fiber body 4 is placed in a coagulating liquid (an aqueous solution of ethanol or acetone with a concentration shown in Table 2 is used; liquid depth: 14 cm, temperature: approximately 0° C.) 17 in the first coagulating tank 6.
The hollow filament 4 is then immersed in and solidified, and then the hollow filament 4 is
It passes through the guide roll 5 in the first coagulation tank 6 and the guide roll 7 outside the coagulation tank 6, and then wraps around a pair of rolls 8.9 (distance: 80 as) in the second coagulation tank 11, and rolls between the rolls. is reciprocated 8 times and immersed multiple times in the second coagulation solution (ethanol or acetone aqueous solution with the concentration shown in Table 2, temperature: approximately 0°C) 18 in the second coagulation tank 11 for secondary coagulation,
Finally, it passed through a third coagulation bath and was wound up in a wet state.

The obtained wet yarn was wound into a skein, dipped in ethanol at about 50°C, then immersed in n-hexane at about 50°C to replace the solvent, dried at about 20°C, and after drying it was further immersed in about 200°C. A hollow fiber was obtained by heat treatment at ℃ for 1 hour.

A bundle of these hollow fibers is fixed to a glass tube with epoxy resin to create a gas permeation test module. Capacity ratio (CO2: CH
&) is 1:10), the permeated gas at 1 kg/-gauge pressure and SO C temperature was analyzed by gas chromatography, and the permeability of each gas component was measured.

The carbon dioxide gas permeation rate (P
CO2) J, and permselectivity between carbon dioxide and methane (PCO2/PCl3) J, etc. are shown in Table 2 (Examples 1 to 42) and Table 3 (Comparative Examples 1 to 7), respectively.

Table 2 (ton 1) Coagulation conditions P■2 dizziness Type of P7 dizziness 1st coagulation night hat 2nd type of coagulation, pco
Sample example Solvent volume % Solvent volume %
Xl0-5 P(2)4 Xl0-' pc.

1 Reference example 1 Ethanol 100 Ethanol 60
3.2 98 - -2 ##80
#60 2.0 93 3.5 493
##70 〃60 2.6 93 4
．． 0 464 - 〃65 #6
0 2.3 79 3.2 455 #
Asen 70 #60 9 46
- -6 Reference-12 Ethanol 80 Ethanol 60 1.2 5B --7#
#70 #60+, 251-
-8- #5 #
60 51 - -9 Reference example 13
Ethanol 80 Ethanol 60 8.4
97 16.0 2810 ##70 #
60 8.2 9716.0 3911##65
da 60 3.8 81 7.4
4612##60 Acetone TO13,012
3--13# Acene 70 Enol
601.0 64 - -14 Reference example 4 Ethanol 80 Ethanol 60 3.6 62
- -15##70 #602.7
85 - -16 〃 #65
- 602.776 - -17#'
Asen 70 #60 6.2
65 - -18 Reference-15 Ethanol 80
Ethanol 60 4.8 60 - -
19 # # 70 #
602.640 - -20##65 -
6 (12,138--2# #70 Acene 70 4.613 - -Table 2 (Ton2) n Reference Example 16 Ethanol 80 Ethanol 6
0 1.6 80- - -27 #
-To #601.491-
-28, - #65 l
601.385 - -32 Is
70 # 603.485 -
-33 # #65 #
602.985 - -38 #
# TOl 602.243 - -39
# #7G #604.
232 - - Table 3 Ratio Do 1 Coagulation conditions Pω2 distribution pH2 comparison 1st mouth m 2nd layer armpit - Shi L [911 molten Wl1m R & Volume % Xl0-' PCl4
Xl0-sPCOl Reference-Support Ethanol 80
Ethanol 60 0.3 4 1.8 1
92 ##70 #6G 0.9 16 3.2
393 ##60 #600.2 46 1.8
884 #50 #600.1 - 0.6 99
5 Reference 6 Ethanol 75
10.0 15 23.4 56##65#
600.6 56.0 197 ##55 #60
0.2 40 1.4 84

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a hollow fiber spinning apparatus for carrying out the method of the present invention. FIG. 2 is a partial sectional view showing an example of a hollow fiber nozzle, and FIG. 3 is a plan view of a discharge diagram of the hollow fiber nozzle. 1; Nozzle head for hollow fiber spinning, 2; Orifice, 3
; tube, 4: hollow filament, 5.7.12; guide roll, 6; first coagulation tank, 8.9; pair of rolls, 10i
Presser roll, 11; second coagulation tank, 12; take-up roll, 14; hollow fiber, 15; nitrogen gas supply conduit, 16; dope liquid, 17; first coagulation liquid, 18; second coagulation liquid, 2
0; Core gas. Patent applicant Ube Industries Co., Ltd. Figure 2 Figure 3 □l

Claims (1)

[Claims] An aromatic tetracarboxylic acid component containing biphenyltetracarboxylic acids in a proportion of about 70 mol% or more, and -SO_
About 5 aromatic diamines having 2-divalent groups in the molecule
The soluble aromatic polyimide obtained by polymerizing and imidizing the aromatic diamine component in a proportion of 0 mol% or more in approximately equimolar amounts is dissolved in a phenolic compound. A method for producing a separation membrane, which comprises using the dope as a dope, forming a thin film from the dope, and coagulating the thin film with an aqueous solution containing 60% by volume or more of alcohols or acetones.