JPS60257805A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To obtain a smooth and uniform gas separation membrane high in coefficient of gas transmission and excellent in mechanical strength and heat resistance, by using the gas separation membrane comprising a polyimide compound represented by a specific formula. CONSTITUTION:Org. diamine such as 4,4'-diaminodiphehyl ether is dissolved in DMF under a nitrogen stream and 2,3,5-tricarboxycyclopentyl acetic dianhydride is added to the resulting solution and reacted with said diamine to obtain polyamic acid. After the polyamic acid is diluted by DMF, tertiary amine such as pyridine is added to the dilute solution as a catalyst and org. carboxilic anhydride such as acetic anhydride is added to the solution and the resulting solution mixture is heated to obtain a polyimide solution. Polyimide thus obtained is dissolved in DMF and cast onto the smooth flat surface of a glass plate and dried by hot air to obtain a polyimide membrane having a repeating unit represented by formula (wherein A is a residue of a divalent aliphatic or aromatic compound or an organosiloxane compound).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a gas separation membrane, and particularly relates to a gas separation membrane that has a large gas permeability coefficient, strong mechanical electric current and heat resistance (J Excellent 4T, and is smooth and uniform). .

[Fungi of the invention] Usually, 13 methods are used that involve a phase change such as lt, 11L distillation, and cryogenic separation to separate a mixture into each component substance, but these methods require an energy of more than latent heat. Supply is essential. Moreover, large-scale equipment such as a multi-stage distillation column may be required. On the other hand, the method of using a gas membrane made of a 1a polymer material is advantageous from an energy-saving perspective because it can separate the mixture into its components simply by passing the mixture through it in a gaseous state. It has attracted attention in recent years because it has great potential for miniaturization.

As such a gas component 1111yA, one made of, for example, polydimethylsiloxane is conventionally known. Although this gas separation membrane has a large gas permeation coefficient, it is difficult to increase the gas permeation rate by reducing the membrane thickness because of its low mechanical strength. There is a drawback that in order to obtain the separation ability, the gas separation apparatus must be made large.

Attempts have also been made to separate carbon monoxide and hydrogen from synthesis gas, which is a raw material for Omi and C1 chemicals, using a gas separation membrane. In this case, since the synthesis gas is at a high temperature, a gas component 1lII film having particularly excellent heat resistance is desired. Gas separation membranes used in such applications are known to be made of aromatic polyimide, which has high mechanical strength and excellent heat resistance. Examples of aromatic polyimides include polyimides produced from pyromellitic anhydride and aromatic diamines; however, since aromatic polyimides are generally insoluble in organic solvents, a polyamic acid solution, which is a precursor thereof, is used. The method used was to form a film by casting on the smooth surface of a base material, and then heat it to advance the imidization reaction to form an aromatic polyimide film. However, in this method, since the imidization of polyamic acid is accompanied by a dehydration reaction, defects such as pinholes and voids are inevitable in the resulting film, making it difficult to obtain a smooth and uniform film. Yes, (:J:U4) Polyimide film GEL gas distribution with pinholes, voids, etc. (unsuitable as a film).

[Objective of the Invention 1 An object of the present invention is to provide a gas separation membrane which solves the problems of the prior art described in -f=. That is, an object of the present invention is to provide a gas separation membrane that has a reasonable gas permeability coefficient, excellent mechanical strength, and heat resistance, and which is clean and uniform.

[Configuration 1 of the Invention According to the present invention, it is represented by the following general formula (1) [wherein 8 represents a residue of a divalent aliphatic, alicyclic or aromatic compound or an organafushi 1]xane compound] A gas separation membrane comprising a polyimide compound containing repeating units is provided.

- As for A in the general formula (■), the above general formula (
1) In organic dimine (general formula (■)) or diisocyanate (-general formula (■)), which is a raw material for a polyimide compound in which the repeating unit represented by 1) is
, [(b, etc.).

In addition, the content of the repeating unit represented by the general formula (I) in the polyimide compound included in the J3L of the present invention should be determined based on the total number of repeating units in order to achieve the object of the present invention within 1 minute. It is preferably 25 to 100%, especially 35 to 100%.

Since the polyimide compound used in the gas separation membrane of the present invention is soluble in a certain organic solvent, the solution prepared by dissolving it in the organic solvent is cast, for example, on a smooth surface in the form of a film, and then the solvent etc. By removing and covering, it is possible to easily form a film.

The polyimide compound used in the present invention is, for example, (1
) 2゜3.5-t which is te-1-racarboxylic dianhydride
Ricarboxycyclobentyl citrate-■-anhydride (hereinafter T
A method of imidizing polyamic acid obtained from C△・△1-1) and an organic diamine; (2>1-
It can be produced by a method that avoids the reaction between CΔ.Al-1 and diisocyanate pressure.

TC△・△ in the manufacturing process of 10-ki (1) or 2)
1-'' is 1, for example, a method in which dicyc[]bentadi:L is decomposed with A-syn and oxidized with hydrogen peroxide (British δ' [No. 87
No. 2355, J, Qrg, Chem, 3
．． 8°2537 (1963)), or a method of oxidizing hydroxydisic[lpentadiene obtained by hydrating dicyclopentadiene with nitric acid (West German Patent No. 107812)
It can be produced by dehydrating the 71-RA carboxylic acid obtained by No. 0) etc.

In the method (1) or (2) above, other -11---- carboxylic dianhydride is added to -rCA. Can be used in combination. T.C.
Examples of the tetracarboxylic dianhydride that can be used in combination with A/Δl-1 include aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, etc. can be mentioned. Specific examples of these tetracarboxylic dianhydrides include pyromellitic dianhydride, 3.3', 4.4'-benzophenone tetracarboxylic dianhydride, 3.3', 4.4'
-biphenylsulfonetetracarboxylic dianhydride, 1
．． 2.5.6-buphthalenetetracarboxylic dianhydride, 1,4.5.8-naphthalenetetracarboxylic dianhydride, 2,3.6.7-naphthalenetetracarboxylic dianhydride, furantetra Carboxylic dianhydride, 3.3',
4.4'-biphenylederdetracarboxylic dianhydride, 3.3', 4゜47-cyphthyldiphenylsilane tetracarboxylic dianhydride, 3.3', 4.4' -
Tetraphenyldyrane detracarboxylic dianhydride, 3.
3'.

4.4'-Perfluoroisopropylidene detracarboxylic dianhydride, 1.2,3.4-'7tanetetracarboxylic acid anhydride, 1,2,3.4-cyclopentanetetracarboxylic dianhydride Anhydride, 1,2°4.5-cyclohexanetetracarboxylic dianhydride, 2t 3. '5,6-bicyclo(2,2,2l-7-A-rintetracarboxylic dianhydride, 1 ~ rahid '] no tracarboxylic acid anhydride,) l henohito 1-1 Among them, the use of aromatic tetracarboxylic dianhydride increases the heat resistance of polyimide compounds, which increases the heat resistance by 1 minute.
1111 membrane is advantageous, especially pyromellit M7
1! it water, 3°3', 4.4'-benzono[
Non-7-tracarboxylic dianhydride is preferred. These tetracarboxylic dianhydrides can be used alone or in combination with TCA・△1-(. Examples of combinations include pyromellitic acid. anhydride and 3,' 3t, 4,
a. r, i. "□Basic phenone tetracarboxylic anhydride; 3,3',4.4'-benzophenone 71-racarboxylic anhydride and 3.3',4.4'
- Biphenylsulfone tetracarboxylic anhydride: Pyromellitic anhydride and 3.3'. 4.4'-bensiphenonetetracarboxylic anhydride and 3.

Examples include 3',4,4'-biphenylsulfonte 1-racarboxylic acid anhydride. When these tetracarboxylic dianhydrides are used in combination with TCA-AH, it is preferably used in a proportion of 3 to 75 mol%, more preferably 5 to 65 mol%, based on the total amount. In particular, when aromatic tetracarboxylic dianhydride is used, if the amount used is less than 3 mol%, there is almost no effect of improving heat resistance, and if the amount exceeds 75 mol%, the resulting polyimide compound is Because it is insoluble, the gas content is smooth and uniform! l
This makes it difficult to manufacture the ll film.

The organic diamine used in the method (1) above is a compound represented by the general formula: l-(2N-Ra-NH2-(II) (Ra is a divalent aromatic group, aliphatic group, or alicyclic group). ) is mentioned.The above general formula (TI)
Preferred R il and O
C H3, Y is -CH2-, -C2 H4-,
-O-.

S + C'+ 1 0 H 3 C F 3 1 -. C-, -C-, -SO2- or -〇〇N
11 is 1CH3'CF3, n' is 0 or 1]: -(-C112)-(n = 2-20), nCI-13-(CI- 12) 3-C-(Cf-h)3-
-1 H3 C aliphatic group or alicyclic group having 2 to 20 carbon atoms, formula C, I-(2Il,, 1-(n == 1 = -2G
Monovalent aliphatic or alicyclic groups such as
I can do it.

Specific examples of the organic diamine of the above two general formulas (II) include buff 1-diamine, methanoenylene diamine,
4. /I'-diaminosyfrylmethane, 4.4'-
Schiff 7 minodif], nylethane, benzidine, 4,4'
-Diamino Schiff-1 Nilsulfondo, 4.4'-Diamino Schiff-1 Nilsulfone, 4゜4'-Schif'-Minodino J-Nil-Del, 3.3'-Pensiphenondiamine, 4,4'-Benzyphenondiamine, 1, 5-diaminodiphenyl, 3゜3'-dimethyl-4,/l'-diaminodiphenyl, 3,/I'-diaminobenzanilide, 3,4'-diaminodiphenyl 1-del, meta-1nidylylenediamine, para Xylylene diamine, J dilene diamine, 1,3-propanediamine, tetramethylene diamine, bentamethylene diamine, hexamethylene diamine, henobu methylene diamine, octamethylene diamine, nob methylene diamine, 4゜1'-dimethylhebutamethylene diamine j′mine, 1,4-diaminosif [
1) Non, te] herahydrodicyclobentazine [nylenediamine, hexyloxybentadiamine, 4゜7-methanoindanilenedimethyldiamine, 1-7 lycyclo(6,2,1,0)-landethylenedimethyldiamine etc. and 1 112 N-(C112-)-5i-0-8t (-C
f-12)-N1-123 1 eH3Ct(a 1 1-h N-(CI-h)-5i-(-0-3i←→
Cl12-)-Nth8 1 Of-13CH3 CN3 CN3 1 (!-(2N(CH2)Si (O-3i←→C1"2)
N+-12113 1 Ct-L+ CI-h etc. (Dij'mi as shown) Δ Luganosyl 4-phosphorus can be mentioned. These organic diamines can be used either in type 1 (K-D) or in type 2 (component U).

Among these organic diamines, 1-), the general formula (Tl
) in which Ra is an aromatic group is preferable because the resulting polyimide compound has higher heat resistance, and in particular aromatic diamines in which Ra is represented by, for example 4.4' -Diamino Schiff] Nyl J-ful, 4,4' -Diamino Schiff■
Nilmethane, 4. /I'-di7nominodiphtonylsulfon is preferred.

In the method (1) above, 'C(yo, first -r C△・A
H or as needed
of b mixed with tracarboxylic dianhydride (hereinafter 1・-1r
A solution of polyamic acid in 41 solvents is obtained by reacting T CA -A +-1 etc.) with an organic diamine in an organic solvent. The obtained polyamic acid solution in a solvent is used as it is, or the polyamic acid is recovered from the organic solvent solution by a conventional method, purified if necessary, and then dissolved in an organic solvent again and then subjected to an imidization reaction. Ru.

'It is preferable to carry out the reaction between C△・A I-1, etc. and the organic diamine at the same molar ratio, but as long as the desired polyamic acid is obtained, the ratio of these seven molars may be slightly varied. For example, in order to obtain a high molecular weight polyamic acid, TCA-A1-1 etc. 1) 'vAi'
It is preferable to use about 0.7 to 1.3 moles of organic diamine. Further, the polyamic acid molecule m can also be prepared by adding a monoamine or a dicarboxylic acid anhydride. The reaction temperature during production of polyamic acid is generally 0 to 100°C, preferably 5 to 60°C. Furthermore, as the organic solvent used in this reaction, aprotic polar solvents are generally preferred, such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N
, N-dimethylformamide, dimethyl sulfoxide,
Tetramethylurea, hexamethylphosphate triamide, γ
In addition to a, which includes Bubu 11 fucton, etc., in addition to these polar solvents, - alcohols, which are common solvents,
Nols, /7tons, Fals, lactones, -
1-1-1, halogenated hydrocarbons, hydrocarbons, such as mebral-al-ni-1-, −[f
Rengyol, J-dilene glycol, phenol, m-cresol, aretone, methyl methyl ketone, methyl isobutyl ketone, cyclohexynone, methyl acetate, vinegar M-T-fl, methyl acetate, Diezyl oxalate, Didyl malonate, γ-budyl [
]Lactone, diethyl ether, ethylene glycol dimethyl l-thyl, diethylene glycol dimethyl ether, tetrahydrofuran 1]furan, dimethane 1,2
-Tsuku 1 Lu J Tan 1 Doo. 114-dichlorobutane, 1-lichloroethane, chlorobenzene, O-dichlorobenzene, 4. Zane, helithane, octane, benzene, heluene, xylene, etc. can also be used.

These general organic solvents are desirably used in combination with the above-mentioned aprotic polar solvent, and when used in combination, high molecular weight polyamic acids are easily produced. For example, if a solvent such as aretone/dimethylformamide-7/3 (volume ratio) is used to avoid reacting TCA.A1 or the like with an organic diamine, the reaction system becomes homogeneous, and a polyamic acid having a particularly high molecular weight can be easily obtained.

The amount of solvent to be used is 0.1 to 50 times the total amount of the mixture of diamines, preferably 0.5 to 20 times by weight.

The polyamic acid thus obtained is then subjected to an imidization reaction. In this imidization reaction, the above-mentioned aprotic polar solvent is suitably used as a solvent. Therefore, when a non-brone polar solvent is used in the above reaction between TCA-A t+ etc. and organic diamine, the obtained polyamic acid solution can be used as it is in the imidization reaction.

T.C.A. 8l-J 纺I+f；km うま：l：”
t L- /7'l L7 r'F +- (If an organic solvent other than a polar solvent is used, use a lifting platform, etc. to recover the polyamic acid using a conventional method and purify it if necessary. After IC, it is desirable to dissolve the mixture in a non-101-based polar solvent and carry out the imidization reaction.

The method of imidizing polyamic acid is to mix the organic solvent solution of polyamic acid obtained in this way with
The imidization reaction is carried out by heating the polyamic acid solution in an organic solvent at 60 to 150°C and distilling off the filtrate of 41 in the reaction to the outside of the system. 4. A method of advancing the imidization reaction by heating the polyamic acid solution in the presence of an organic carboxylic acid anhydride and adding a tertiary amine as necessary can be used.

Generally, the last method listed above among the above-mentioned methods is preferred because the reaction proceeds easily. In this method,
The concentration of the organic solvent solution of polyamic acid is preferably 1 to 1.
50% by weight, particularly preferably 1 to 30% by weight.

Further, it is preferable that the boiling point of the core carboxylic acid anhydride used in the imidization reaction is 250° C. or lower. If the boiling point of the organic carboxylic acid anhydride exceeds 250°C, the organic carboxylic acid anhydride will not be removed at the same time when the solvent is removed by heating when forming a film using the imidization reaction solution as it is. It will remain in the film and have an adverse effect on physical properties. Examples of the organic carboxylic acid anhydride used include acetic anhydride, propanoic anhydride, acetic anhydride, isoacetic anhydride, and arsenic anhydride. Mixed acid anhydrides of these organic carboxylic acids, such as acid salts and hydrates obtained from acetic acid and propimenic acid, can also be used. When using an organic carboxyl salt, the amount used is 0.2 per mole of repeating structural unit of polyamic acid.
~2048 mol is preferable. If it is less than 0.2 times the mole, the imidization reaction will proceed slowly, and if it exceeds 20 times the mole, the solubility of the polyamic acid in the 41 solvent will be low. Furthermore, when an organic carboxylic acid anhydride is used, a tertiary amine may be added as a catalyst if necessary to accelerate the imidization reaction. In addition to promoting the imidization reaction, it also has the effect of suppressing the decrease in solution viscosity of the obtained polyimide. ℃ or less is preferable.
Aromatic tertiary amines such as N-dimethylaryne, pyridine, 2-methylpyridine, N-methylimidazole,
Examples include heterocyclic compounds such as quinoline and isoquinoline. The amount of tertiary amine added is preferably 20 (Rt or less) per mole of repeating structural unit of polyamic acid.
If the amount exceeds 0 times the mole, the solubility of boriamic acid in 41 organic solvents tends to decrease.

The reaction temperature of the imidization reaction when using a carboxylic acid anhydride is preferably O to 200'C1, particularly preferably 20 to 170C. If the temperature is less than 0°C, the progress of the imidization reaction will be delayed, and if the temperature exceeds 200'C, the polyimide molecule m will drop significantly.

In the method (2) above, (Puru diisocynonone-1.dot(, Ll General formula: OCN Rb N CO...
The compound represented by (III) [Rb 1; L 2 filli represents an aromatic group, an aliphatic group, or an alicyclic group.

Preferred examples of Rb in the general formula (-J) include, for example, "In the formula, X+, X2, Y
C,L-CLl 2- , -C21-14--1-
0-1-8-1CH3CF 3 (1 -C-1-C-,, -3 O@z- 1 CI-13' CF3 Makoha-CONl) -1 [1 indicates O or 1] Ff-1-(Ctl 2 ) n-
(n-2=□20), H3 Akebono 143 A fatty acid β having 2 to 20 carbon atoms, j! , :
:Lk +, 1, alicyclic group, etc. are ¥-. Toward improving the heat resistance of polyimide compounds that can be used in the stomach.
, in order that 1ma1) is an aromatic group (Irma(
〕stomach,.

Specific examples of the above diisocyanate
-lylene diisocyanate, 2, 6-h lylene diisocyanate-1~, p-) J21 non-diisocyanate
to, m-FJ nylene diisocyanate-1=, 4.

4'-diphenylmethane diisocyanate, 4°4'
-Schifnyl I-Fludiisocyanate-1.,1゜4'-
Schiff
Ginoenyl Sulfur Wide Diisosane 1~. 1. Aromatic diisocyanes such as 5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, tolidine isocyanate, 4,4'-biphenyl diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, etc. Compound, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1゜4-dos(isocyanatemethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexyl ether diisocyanate-1~ Compounds such as alicyclic diisocyanate-1, butane diisocyanate, hexyrimethylene diisocyanate,
Aliphatic diisocyanate compounds such as octamethylene diisocyanate, lysine diisocyanate-1., and trimethylhexamethylene diisocyanate can be mentioned. These can be used alone or in combination.

In the method (2) above, a polyimide compound solution is obtained by reacting T CA -A H or the like with a diisocyanate in an organic solvent. Reaction (,: Examples of organic solvents used include N-mef-2-pyrrolidone, N,N-
Examples include aprotic polar solvents such as dimethylarenamide, N,N-dimethylformamide, dimethyl sulfoxide, α-/brolactone, and tetramethylurea, and phenolic solvents such as cresol, xylenol, and halogenated alcohol. It will be done. These can be used alone or in combination. Furthermore, in addition to these generally high-boiling point solvents, a low-boiling solvent or a low-toxicity solvent can also be mixed to the extent that the polyimide compound does not precipitate, thereby improving the ease of handling of the polymerization solution.

These low boiling point solvents and low toxicity solvents include
Examples of ketones include O 1 R3CR4 (R3R3 and R4 are the same or different, methyl group, 1 tyl group, i n-propyl group, i-propyl group, n -ethyl group, 1t
(i-butyl group or t-ethyl group), aromatic ketones such as acetonoenone, alicyclic ketones such as Schiff[1hextnanone, isophon[]one, etc. Misaki, 1,2-dimethoxyethane, diethylene glycol dimethyl able,
Glymes such as tri-ethylene glycol, lJ-ru, dimethyl-1-tyl, 175-10 CH2CR20CRe (R5 is a methyl group, ethyl group, i-propyl group, n-propyl group, n-butyl group,
Examples include cellosolve esters represented by i-butyl group or t-butyl group, and R6 is a methyl group or ethyl group, alicyclic ethers such as detrahydrofuran and dioxilene. can.

It is preferable that the reaction ratio of TC△・He11 etc. and the diisocyanate is carried out in equimolar amounts, but a slight excess or deficiency may be used.

In order to obtain a high molecular weight polyimide compound, -
It is preferable to use about 0.7 to 1.3 moles of diisocyanate per mole of [CΔ・A)-1 etc.

The amount of solvent used is 1'rcA-Atiichido diisocyanate.
It is preferably 0.5 to 20 times the total amount of 1. by weight.

Further, the reaction of diisocyanates such as TCΔ and Δ1-1 can be carried out by adding a catalyst. Examples of the catalyst include tertiary amines and quaternary ammonium salts. Specifically, tri1-tylamine, tripropylamine, tributylamine, N, N, N',
N'-te1 heramethyl diethylene diamine, N, N, N'
, aliphatic tertiary amines such as N'-detramedylene-1,3-butanediamine, tri-dylenediamine, N-
Alicyclic box 3 handling amines such as methylmorpholine, N-ethylmorpholine, pyridine, α-picoline, quinoline,
2-(N-phenylcarbamoyl)-1,1,3,3-
Aromatic tertiary amines such as tetramethylguanidine, pentamethylguanidine, hezotamethylisobicnononide, N,N-dimethylaniline, N,N-di]-del)7niline, dimethylbenzylamine, benzyldimethylphenyl Ammonium chloride, benzyldimethyl 7tradecyl 7/ammonium chloride, benzyltriethylammonium chloride, benzyltriethylammonium chloride, penzyltrimethylammonium chlorite, cedylbenzyldimethylammonium chloride 1-
1 light, cell rubiridinium chloride, t f rubyridinium chloride (nium chloride, ethyl 1-ly n-
Examples include quaternary ammonium salts such as propyl, ammonium hydride [ ] 1 ↓ ide, pentamethonium yossite, phenyltrimethylammonium bronide, and ti--n-butylammonium chloride. The amount of catalyst added is preferably 0.001-.05 mol, particularly 0.0
1 to 0.2 liters is preferred.

The reaction temperature of TCA-AI-1 etc. and diisocyanate is preferably 50'C to 250°C, particularly preferably (,18
0.200'C, reaction time is usually 0.5-.
There is time at 20:00.

The polyimide compound obtained by the method (1) or (2) above has a gas content of 111 t uq (j.
Intrinsic viscosity ηinh (concentration 0.5 Q
i ('+Qm+, solvent dimethylborumamide, measurement temperature ζ]0゛0) is preferably 1; 10.5 dl/Q or more,
Particularly preferred is 0.05...20 dl/g.

7. If the characteristic degree is less than 0.05 dl/g, the film formability is poor. If it is less than 13, the moldability is insufficient and undesirable. Note that the intrinsic viscosity ηinh is a viscosity expressed by (1- is the flow rate of the borine solution, and 10 is the flow rate of dimethylbormamide).

Hereinafter, the compound obtained as shown in L is obtained by casting an organic solvent solution of a polyimide compound onto the smooth surface of a base material such as a glass base or a metal plate. rear,
It is possible to form a film by removing the organic solvent, etc. by heating or other methods.
After the polyimide compound is recovered from the organic solvent solution of the compound, it is redissolved in a solvent, and then a film is formed using the above method. Examples of organic solvents used for this redissolution include C (the above-mentioned aprotic polar solvents), norol solvents, and the like.

[Effects of the Invention] The gas separation membrane of the present invention made of the polyimide compound thus obtained has a large permeability coefficient for various gases, has excellent heat resistance ++3J and mechanical strength,
Moreover, there is a smooth and uniform /ffi film C.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (1) 200 ml of N,N-dimethylborumamide (1) MF was added to 200 ml of N,N-dimethylborumamide (1) MF in a flask equipped with a nitrogen gas inlet and a nitrogen gas introduction device.
20.00 g (0.1 mole) of Nilniedel was added and dissolved. After dissolving, add 2.3.5-1 lycarboxycyclopentyl acetic dianhydride to the solution. /12+ (0
, '+ sil) to nitrogen - first class master - (゛) After adding this mixture to room temperature ('+ 8115 hours, it is 1 town.
c polyamic acid solution was obtained], 23, obtained l
ζ Polyamic acid solution (, -1 further)) M 2
After diluting by adding 00ml, 47.40g of pyridine and anhydrous acid resistance 102.09<J were added, and the mixture was reacted by heating at 'I3(,)°C for 5 hours to quench the polyimide solution.

The resulting polyimide solution was poured into a large amount of methanol to coagulate, collected, and dried under vacuum at 100°C.

Measure the intrinsic viscosity of the IJ-treated polyimide.1. :However, 1.58 dl/q in DMF (c=o, 5q/old)
There was C.

In addition, the infrared absorption spectrum of this polyimide was measured and found to be 178Qcnr'(> c = o stretching) J
3. J: Hill 360cn+-"(> c-N <
On the other hand, it was observed that the absorption of 3300cm'(> N -1-l stretching) and 166Qcv' (C=O stretching of the amide base) observed with polyallic acid had disappeared. It was found that ring formation due to imidization had progressed to at least 95%.

It can be seen from the above results that a polyimide containing 95% or more of the total repeating unit of the following formula was obtained.

(2) Next, the polyimide obtained as above is D
W4 was prepared by dissolving it in MF to make a 20% by weight solution. This solution was cast onto a glass plate with a smooth surface, dried at 130°C for 2 minutes using a hot air dryer, and then at 150°C for 2 minutes, and then vacuum-dried at 150°C overnight.
A polyimide film with a thickness of 6 μm was obtained.

When the stress-strain characteristics of the obtained film were measured, the tensile strength was 14201<LI/cm2.110%, indicating excellent mechanical properties Y'i.

Also, from the measurement of dynamic viscoelasticity (llllz), the main dispersion wA of this polyimide is 400°C J'1. It has been measured to have a high heat resistance.
.

Next, the gas permeability of the obtained polyimide film was measured by a high vacuum method to evaluate its performance as a gas separation and desorption system. That is, we calculated the gas permeability coefficient, gas separation coefficient, and gas permeation rate at 30°C and 100°C for hydrogen, helium, nitrogen, oxygen, carbon dioxide, methane, and the results are shown in Table 1. Met. Note that the gas permeability coefficient was determined by the following formula.

Furthermore, the gas separation coefficients are shown as relative values, with the permeability coefficient of nitrogen being 1 and the permeability coefficients of other gases being expressed as relative values.

Comparative Example Commercially available polyimide film (thickness 5411IIl, 1″
The gas permeation rate and gas permeability coefficient at 30°C and 100°C (manufactured by Copon, trade name Kapton) were determined in the same manner as in Example 1. Roughly speaking, the gas permeability coefficient determined here was
The ratio to the gas permeability coefficient determined in the example under the same conditions was 81n. These results are shown in Table 2.

From the results in Tables 1 and 2, it can be seen that the gas content 11f membrane of the present invention has a permeability coefficient about 2 to 8 times that of the commercially available polyimide membrane.

(Margin below)

Claims (1)

[Scope of Claims] A polyimide containing a repeating unit represented by the following general formula (1) [wherein A represents a residue of a divalent aliphatic, alicyclic or aromatic compound or an organosiloxane compound] Gas separation membrane made of compounds