JP2555617B2 - Gas separation membrane and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas separation membrane having good permeability, selectivity, durability and scratch resistance.

[Prior Art] In recent years, attention has been focused on gas separation by a membrane method, particularly a method of obtaining oxygen-enriched air by a membrane separation. The membrane that can be practically used for this membrane separation must satisfy the conditions of high gas separation and high gas permeability. In order to meet these required characteristics, various separation membranes have been devised in recent years by studying membrane materials, membrane structures, membrane production methods, and the like.

(1) In JP-A-54-146277, JP-A-56-40413, JP-A-56-92925 and JP-A-56-92926, poly (4-methyl-1-pentene) is used. Gas separation membranes made of polyolefins such as and the like and methods for producing the same have been proposed. Further, Japanese Patent Publication No. 59-30169 proposes a gas separation membrane formed from a composition comprising a methylpentene polymer and a polyorganosiloxane-polycarbonate copolymer. In addition to these, JP-A-56-
28605 discloses a gas permeable membrane material containing an olefin polymer partially crosslinked with a polyorganosiloxane as a main component.

(2) Further, JP-A-59-32903 proposes a separation membrane formed of modified poly (4-methyl-1-pentene) obtained by graft-copolymerizing an organic silane derivative of unsaturated carboxylic acid. .

(3) Further, in Japanese Patent Publication No. 43-25022, a gas separation membrane made of polyarylene oxide is further disclosed in
No. 216802 proposes a gas separation membrane made of silylated polyphenylene oxide.

(4) As an example of applying a crosslinked polyarylene oxide to a gas separation membrane, a gas comprising polyarylene oxide crosslinked with an amino-modified polysiloxane is disclosed in JP-A-59-222203 and JP-A-62-53373. The separation membrane
Further, JP-A-60-51525 discloses a crosslinked polyarylene oxide film prepared by reacting a halogenated polyarylene oxide with a crosslinking agent such as ammonia.

(5) Furthermore, Polymer Preprints, Japan 35 (3), 425
(1986), poly (2-trimethoxysilyl-1,3-
The gas permeability of butadiene) is being investigated.

(6) On the other hand, as the structure of the film, for example, JP-A-59-
Japanese Patent No. 112802 discloses a permselective membrane in which two layers of a silicone-based polymer and a polymer having a glass transition temperature of room temperature or lower such as polyolefin or polydiene are supported on a porous support membrane.

(7) Further, JP-A-59-59214 discloses that the oxygen permeability coefficient of polyorganosiloxane or the like is 10 ^-8 to 10 ^-7 (cm ³ · cm /
cm ² · sec · cmHg) a first membrane made of a material having a cm ² · sec · cmHg) is laminated on a porous support membrane, and a second membrane made of a material having a high separability of oxygen and nitrogen, such as polyvinyl pivalate. A permselective membrane in which is laminated is shown.

[Problems to be Solved by the Invention] However, the above (1) has low selectivity when separating a specific gas from a mixed gas, and (2) improves the selectivity, There was a problem in terms of film strength and film formability.

In the gas separation membrane of (3), since the polyarylene oxide does not have a crosslinked structure, the thin film forming property and the membrane durability were insufficient.

Further, (4) has a problem in that a crosslinking agent needs to be added in a post-treatment for crosslinking the halogenated polyarylene oxide, which complicates the manufacturing process. Also,
In (5), the film made of poly (2-methoxysilyl-1,3-butadiene) has low film strength, and reproducible measurement data have not been obtained particularly when the film material is in a glass state.
Also, looking at the measurement data obtained in the rubber state,
The film material α (= PO ₂ / PN ₂ ) was as low as about 3.

In the permeation membranes such as (6) and (7), the uppermost layer of a thin film made of a polymer having a high gas separation property has a low mechanical strength, and therefore the thin film formed by winding at the time of film formation is used. There was a problem that the layer was rubbed, and a pinhole was generated due to the spacer necessary for securing a gas flow path when it was incorporated into the module, contacting the thin film layer, and the separation performance was deteriorated. .

[Means for Solving Problems] The present invention has the following configuration in order to solve the problems.

That is, the present invention is (1) a thin film formed of a polymer selected from polyolefins and polyarylene oxides, which has an active functional group that self-crosslinks or reacts with a crosslinking agent to crosslink, and A gas separation membrane comprising:

(2) From a first thin film made of a polymer having excellent gas permeability on at least a porous support, and a polyolefin or polyarylene oxide having an active functional group that self-crosslinks or reacts with a crosslinking agent to crosslink. The present invention relates to a gas separation membrane in which a solvent is evaporated from a solution in which a selected polymer is dissolved and a thin film formed is laminated with a second thin film having a cross-linking bond composed of oligosiloxane bonds.

The polyolefin used in the present invention is formed from an olefin having 2 to 18 carbon atoms, more preferably 2 to 10 carbon atoms, and examples thereof include ethylene, propylene, isobutylene, 1-butene and 3-methyl-1. -Butene, butene derivatives such as 3-cyclohexyl-1-butene, 1-pentene, 4-methyl-1-pentene, pentene derivatives such as 3-methyl-1-pentene, 1-hexene, 5-methyl-1-hexene Hexene derivatives such as 1
-Heptene, heptene derivatives such as 5-methyl-1-heptene, octene derivatives such as 1-octene, decene derivatives such as 1-decene, vinylcycloalkane derivatives such as vinylcyclopentane and vinylcyclohexane, allylcyclohexane such as allylcyclohexane Alkane derivatives, styrene, styrene derivatives such as α-methylstyrene, α-olefins such as silicon-containing alkenes such as vinyltrimethylsilane and allyltrimethylsilane, internal olefins such as norbornene, diisopropyl fumarate, di-n-propyl fumarate, and fumarate. Fumaric acid esters such as dicyclohexyl acid and di-t-butyl fumarate, acrylic acid esters,
It is a homopolymer or copolymer formed from unsaturated carboxylic acid esters such as methacrylic acid esters and vinyl pivalate. Among these polymers, α-olefin polymers, more specifically, homopolymers or copolymers containing at least one selected from propylene and 4-methyl-1-pentene are excellent in film strength. More preferably, a homopolymer or a copolymer containing 4-methyl-1-pentene as a constituent component is more preferable because it is particularly excellent in selective permeability. Further, polydienes such as poly (butadiene) and poly (isoprene) have a double bond in the polymer main chain and thus have poor oxidation resistance and are not suitable for gas separation of enzymes and the like.

Further, the polyolefin used in the present invention preferably has a weight average molecular weight of 10,000 or more and a polymerization degree of 100 or more.

The basic structure of the polyarylene oxide used in the present invention is represented by the general formula Is represented by Here, m is an integer of 1 to 3, preferably m
Is 2 and n is an integer of 75 or more, preferably 100 or more. R's may be the same or different and are selected from an alkyl group, a substituted alkyl group, a phenyl group, a substituted phenyl group, a halogen atom, an alkoxy group, an alkenyl group, an alkynyl group, an amino group and the like. Substituent R
The number of carbon atoms contained in is preferably 15 or less, more preferably 8 or less. The aromatic ring contained in the polymer main chain preferably has a para position in connection with an oxygen atom in the general formula and a connection with an oxygen atom in an adjacent repeating unit, but some of the connections are at other positions. But it doesn't matter.

The polyarylene oxide represented by the general formula is
At least one hydrogen atom or halogen atom is contained on the main chain aromatic ring, or at least one hydrogen atom or halogen atom is held on the carbon atom adjacent to the main chain aromatic ring. Need to be present. Especially when R is an alkyl group, it is necessary that at least one hydrogen is contained on the carbon atom adjacent to the main chain aromatic ring. The repeating unit contained in the polymer may be a single unit or different units.

The substituent R is preferably an alkyl group. The alkyl group may be long-chain or branched, and examples thereof include methyl, ethyl, n-propyl, i-propyl,
Examples thereof include n-butyl, i-butyl, sec-butyl, n-pentyl and the like. The polyarylene oxide more preferably used in the present invention is poly (2,6-dimethyl-1,4-phenylene oxide).

These polyarylene oxides can be synthesized by various methods. That is, it can be synthesized by a method by oxidative coupling polymerization of a substituted phenol monomer corresponding to the above general formula, or a condensation polymerization method of a halogen-substituted phenol corresponding to the above general formula, a method by a polymer reaction of polyarylene oxide, etc., It is not limited to these.

Further, as the polyarylene oxide used in the present invention, a hydrogen atom on an aromatic carbon atom of the main chain aromatic ring contained in the above general formula or on an aliphatic carbon atom adjacent to the main chain aromatic ring and / or All or part of a halogen atom or the like is substituted with a non-crosslinkable silicon group such as an organosilyl group, an organosiloxane group, or an organosylalkylene group, or an unsaturated bond or the like contained in the general formula Alternatively, a polyarylene oxide having a structure in which a non-crosslinkable silicon group such as an organosilyl group, an organosiloxane group, or an organosylalkylene group is partially added can be used.

There are various methods for synthesizing these polyarylene oxides containing a silicon atom, but metallized polyarylene oxides and organoorganic compounds prepared from polyarylene oxides, halogen-containing polyarylene oxides, etc. using organometallic reagents, etc. Coupling reactions with halosilanes, organohalosiloxanes, organohalosylalkylenes, etc. (methods described in JP-A-62-7418, JP-A-62-30524, etc.) and substituents having unsaturated bonds Examples thereof include a hydrosilylation reaction of polyarylene oxide, a method of reacting an organosilane having a reactive group such as an epoxide, an isocyanate, a diazo group, an organosiloxane, an organosylalkylene and the like with a polyarylene oxide. For the synthesis of the above-mentioned metallized polyarylene oxide, an organometallic reagent such as n-butyllithium, sec-butyllithium, tert-butyllithium, phenyllithium or the like is used, if necessary, N, N, N ', N'-tetra- It can be used in the presence of amines such as methylethylenediamine.

The organosilyl group, the organosiloxane group, the substituents on the silicon atom contained in the organosylalkylene group, may be the same or different, hydrogen, an alkyl group having 1 to 12 carbon atoms, a substituted alkyl group, An alkenyl group, a phenyl group, a substituted phenyl group and the like are preferable.
When an alkyl group is used as the substituent, the total number of carbon atoms contained in the substituent on one silicon atom is 2 to 3
The range of 0, more preferably 2 to 24 is preferable. 3 carbon atoms
If it exceeds 0, the mechanical strength (breaking strength, Young's modulus) of the film decreases, and the formability of the thin film decreases, which is not preferable.
Specific examples of the substituent include, but are not limited to, the following substituents.

That is, hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert.
-Alkyl groups such as butyl, neopentyl, hexyl, octyl, cyclohexyl, chloromethyl group, chloropropyl group, mercaptopropyl group, cyanoethyl group, benzyl group, trichloropropyl group, methoxyethyl group, nitropropyl group, 2- (carbomethoxy ) Ethyl group, dichloromethyl group, trifluoropropyl group, (perfluorohexyl) ethyl group, (perfluorooctyl) ethyl group and the like (substituted) alkyl group, cyclohexenyl group,
Vinyl group, alkenyl group such as allyl group, phenyl group, 4
And (substituted) phenyl groups such as a methylphenyl group, a 4-nitrophenyl group, a 4-chlorophenyl group, a 4-methoxyphenyl group, and a pentafluorophenyl group.

The active functional group that self-crosslinks or crosslinks by reacting with a crosslinking agent, active silyl group, hydroxyl group, epoxy group, isocyanate group, ester group, amino group,
A thiol group, an unsaturated alkyl group, a carboxylic acid anhydride group or the like can be used, but an active silyl group or a carboxylic acid anhydride group is preferable from the viewpoint of easily forming a crosslinked structure.

As the active silyl group, on a silicon atom, for example, a methoxy group, an ethoxy group, a propoxy group, an alkoxy group such as a propenoxy group, an acyloxy group such as an acetoxy group,
_{(CH 3) 2 C = NO-} , C 2 H 5 CH 3 C = NO- , and _{(C 6 H 5) 2 C} = N
O- and other oxime groups, alkylamino and other substituted amino groups, acetamide and other amide groups, alkylaminooxy groups, halogen groups, hydroxyl groups, silyl groups having hydrogen and the like as substituents, vinyl groups, allyl groups, etc. An alkenyl group of which is bonded to a silicon atom, or an alkyl group, an aryl group or the like having a functional group such as an epoxy group, an isocyanate group, an amino group, a hydroxyl group or a thiol group is bonded to a silicon atom. Examples of the preferred active silyl group include an alkoxysilyl group, an acetoxysilyl group and an oxime silyl group.

Further, the cross-linking agent that reacts with the active functional group may be a compound having a plurality of functional groups that undergo a condensation reaction, an addition reaction and a substitution reaction with the active functional group, and may be a polyolefin having an active functional group or a polyarylene oxide. It is preferable that they coexist in a dissolved solution.

As a method of introducing an active functional group into a polymer such as polyolefin or polyarylene oxide, there are a copolymerization method with a monomer having an active functional group, a graft method of introducing a side chain having an active functional group, and the like.

Examples of the grafting method include a method of reacting an unsaturated compound having an active functional group in a solution state or a molten state in the presence of a radical initiator such as an organic peroxide, n-butyllithium, sec-butyl. Lithium, tert
There is a method of reacting a metalized polymer prepared by using an organometallic reagent such as butyllithium or phenyllithium with a reagent having an active functional group.

When the active functional group is an active silyl group, the method for introducing the active silyl group into the polyolefin is preferably grafting with an unsaturated compound, and specific unsaturated compounds include vinyltrimethoxysilane and vinyldimethylmethoxysilane. , Vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinyltriisopropoxysilane, vinyltriacetoxysilane, vinylmethyldiacetoxysilane, vinylmethylbis (methylethylketoxime) silane and the like.

Further, in order to introduce an active silyl group into polyarylene oxide, it is preferable to react a metalized polyarylene oxide prepared using an organometallic reagent or the like with a reagent having an active silyl group. As a specific reagent having such an active silyl group, methoxydimethylchlorosilane,
Halogen-containing compounds such as dimethoxymethylchlorosilane, trimethoxychlorosilane, ethoxydimethylchlorosilane, diethoxymethylchlorosilane, triethoxychlorosilane, and phenyldimethoxychlorosilane, γ-
Epoxy compounds such as glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane, trimethoxysilane, triethoxysilane, dimethoxymethylsilane, diethoxymethylsilane, tris (2-propanone oxime) silane, Hydrosilane compounds such as tolyl (2-butanone oxime) silane, vinyltrimethoxysilane, vinyltriethoxysilane,
Vinylmethyldimethoxysilane, vinylethyldimethoxysilane, vinyltriacetoxysilane, vinyltris (2-propanone oxime) silane, vinyltris (2
Examples thereof include vinylsilane compounds such as -butanone oxime) silane.

Further, as a method of introducing a carboxylic acid anhydride group into a polyolefin, a method of reacting an unsaturated compound such as maleic anhydride in the presence of a radical initiator such as an organic peroxide is preferable.

The amount of the active functional group introduced into the polyolefin or the polyarylene oxide can be varied within a wide range depending on the type of the active functional group, the type of the polymer, the conditions of the crosslinking reaction, the desired degree of crosslinking and the like. When the active functional group is an active silyl group and the polymer is a polyolefin, the amount of the active silyl group introduced in the polyolefin is 0.005 to 12% by weight, particularly 0.005 to 12% by weight, when the silicon content in the polyolefin is used as an index. It is preferably 5% by weight. When the active functional group is an active silyl group and the polymer is a polyarylene oxide, the amount of the active silyl group introduced in the polyarylene oxide is 0 when the silicon content in the polyarylene oxide is used as an index.
It is preferably from 05 to 12% by weight, particularly from 0.05 to 10% by weight. Further, the active functional group is a carboxylic acid anhydride group, when the polymer is a polyolefin, the introduced amount of the carboxylic acid anhydride group is 0.01 to 10 mol% when expressed by the mole fraction of the carboxylic acid anhydride group in the polyolefin as an index. It is particularly preferably 0.1 to 5 mol.

As a solvent for dissolving a polymer selected from polyolefins and polyarylene oxides having such an active functional group, it must be a non-solvent that does not destroy the structure on the porous support and be a good solvent for the polymer. However, it must be selected depending on the porous support used. Specific examples of such a solvent include cyclohexane, cyclohexene, and chloroform when a polysulfone porous support membrane or a polyimide porous support membrane is used as the porous support. In addition to this, Japanese Patent Application Sho 61-
As described in 76181, it is preferable to dilute a solution of a polymer having an active functional group with a solvent having a low surface tension to obtain a uniform solution in order to obtain a pinhole-free thin film. Examples of the low surface tension solvent include trichlorotrifluoroethane, trichlorofluoromethane, isopentane, dimethyl ether, diethyl ether and the like.

A solution prepared by dissolving a polymer selected from polyolefins and polyarylene oxides having such an active functional group in a solvent is a first thin film made of a polymer having excellent gas permeability on a porous support or on a porous support. It is directly coated on the composite film provided with and the solvent is evaporated to form a thin film, or the solution is cast on the water surface and the solvent is evaporated on the water surface to form a thin film. There are two methods, but either method is acceptable.

In the present invention, a crosslinking reaction proceeds in the process of solvent evaporation from the solution, and at the end of evaporation of the solvent, a thin film having a crosslink bond is formed, and the thin film has excellent mechanical strength and separability, and is free from pinholes. It is characterized by being. The progress of the crosslinking reaction in the evaporation process of the solvent, in the case of a polymer having an active silyl group, a method of self-crosslinking by the reaction of active silyl groups, a method of crosslinking the active silyl group using a crosslinking agent, etc. is there. The former provides cross-linking by forming a bond containing a silicon atom, preferably an oligosiloxane bond, from an active silyl group.
More specifically, the active silyl group contains a hydrolyzable substituent such as an alkoxy group, an acyloxy group and an oxime group,
It is a method of forming a crosslinked structure by condensation of silanol groups derived from this. Furthermore, in order to efficiently carry out this crosslinking reaction, it is preferable to use a crosslinking catalyst and / or to heat it and / or to allow moisture (including moisture in the air) to be present.

As such a crosslinking catalyst, dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin diacetate,
Organic tin such as stannas octanoate, iron 2-ethylhexanoate, carboxylate such as cobalt naphthenate, organometallic compound such as titanate, organic amine such as ethylamine, dibutylamine and pyridine, acid such as fatty acid There is. Among these, dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin diacetate and stannas octanoate are preferable. Evaporation of the solvent is carried out at room temperature to 200 ° C, preferably 50 ° C to 150 ° C.

The oligosiloxane bond that holds the crosslinked structure in the polyolefin and polyarylene oxide is Those containing a bond (n is a natural number), more specifically a general formula (X ₁ , X ₂ , X ₃ and X ₄ each represent —OSi—, alkyl, aryl, alkoxy, acetoxy, oxime, hydroxyl group, etc.). When the number of siloxane bond units (n) contained in one crosslinked site, that is, one crosslinked structure, is 1 or more and 3 or less, the selectivity is improved, and n is particularly preferably 1. Further, in order to provide a crosslinked structure to the polyarylene oxide, in addition to the siloxane bond, a carbon-carbon bond, a carbon-oxygen bond, a carbon-
Ordinary organic polymer and inorganic polymer forming bonds such as nitrogen bond, carbon-sulfur bond, carbon-silicon bond, ester bond, amide bond, urethane bond and urea bond may be used together.

As a constituent component of the gas separation membrane of the present invention, other polymer may be contained as the second component in addition to the polyolefin and the polyarylene oxide having the crosslinked structure by the oligosiloxane bond. That is, as the second component, various olefin-based polymers such as poly (4-methylpentene), poly (vinyltrimethylsilane), polystyrene, poly (di-tert-butyl fumarate), poly (2,6-dimethyl- 1,4-phenylene oxide) and other aromatic polyethers, polydimethylsiloxane, polymethylphenylsiloxane and other polyorganosiloxanes, silphenylene-siloxane copolymers, polycarbonate-polysiloxane copolymers, polysulfone-polysiloxane copolymers Polyorganosiloxane copolymers such as polymer, substituted polyacetylene such as poly (tert-butylacetylene), poly (trimethylsilylpropyne), polyorganophosphazene such as poly (bisethoxyphosphazene), poly (oxy-1) , 4-Phenylenesulfonyl-1,4-
Phenylene), poly (oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-1,4-phenylenepropylidene-1,4-phenylene), and other polysulfones. Examples of the addition method include a mixing method with the second component polymer and a laminating method with the second component polymer.

The content of the second component polymer is not critical as long as various properties of the film are not deteriorated, but is usually 50% by weight or less.

The gas separation membrane of the present invention may take any form of a polyolefin having a crosslinked structure, an asymmetric membrane made of polyarylene oxide, and a composite membrane. The asymmetric membrane may be in any form such as a flat membrane, a hollow fiber, or a tube, and the membrane thickness is usually 1 to 300 μ in order to have practical mechanical strength and to obtain a sufficient gas permeation rate. ,
It is preferably 5 to 100 μ. As the film of the present invention, a film formed by a known method, for example, a wet method, a dry-wet method, a melting method, a stretching method or the like is appropriately used.

The composite film having a thin film of polyolefin or polyarylene oxide having a crosslinked structure of the present invention has a form in which at least one thin film is provided on a porous support.

The porous support for holding the thin film of the present invention has a function of supporting the thin film, and the size of pores on the surface is about 10Å
~ 5000Å, preferably about 10Å-1000Å. Further, it is preferable to have an asymmetric structure so that the gas permeation resistance is unlikely to occur. The gas permeability is 10 at the nitrogen permeation rate.
It is preferably (m ³ / m ² · hr / atm) or more. Examples of the material include glassy porous material, sintered metal, ceramics, cellulose ester asymmetric membrane, polyethersulfone asymmetric membrane, polysulfone asymmetric membrane, and polyimide asymmetric membrane. Among these, the polysulfone asymmetric membrane is preferable because it has sufficient gas permeability and has an appropriate pore size.

The thickness of the cross-linked polyolefin or polyarylene oxide thin film is preferably 0.2 μm or less, as long as pinholes do not occur.

Further, the gas separation membrane of the present invention is preferably a composite membrane in which a first thin film made of a polymer having excellent gas permeability is provided between the thin film of the crosslinked polyolefin or polyarylene oxide and the porous support. is there. Here, a polymer having excellent gas permeability provided on a porous support means a polymer having an oxygen permeability coefficient PO ₂ of 1 × 10 ⁻⁸ (cm ³ · cm / cm ² · cmHg · sec) or more. Is. Specific examples of such a polymer include polyorganosiloxane, crosslinkable polyorganosiloxane,
Polyorganosiloxane / polycarbonate copolymer,
Examples thereof include polyorganosiloxane / polyphenylene copolymers, polyorganosiloxane / polystyrene copolymers, and polytrimethylsilylpropyne. Among these, crosslinked polydimethylsiloxane is most preferable because it has high mechanical strength and a large oxygen transmission coefficient. This crosslinked polydimethylsiloxane differs in the performance of the obtained thin film depending on the production method.
The cross-linked polydimethylsiloxane thin film obtained by the production method described in 61-60272 and Japanese Patent Application No. 61-59269 is preferable because it has excellent gas permeability and few pinholes.

As a method of providing the first thin film made of crosslinked polydimethylsiloxane on the porous support, specifically, there are methods shown in the following a to c.

I. As described in JP-A-60-257803, polydimethylsiloxane having a silanol group at a terminal and a tetrafunctional or higher functional silane cross-linking agent, or a solution obtained by mixing a tetrafunctional or higher functional siloxane cross-linking agent with a solvent is porous. Method obtained by coating on a quality support.

B. A solution obtained by mixing a polyorganosiloxane whose side chain ends are amino-modified and a side chain terminal isocyanate-modified polyorganosiloxane as shown in Japanese Patent Application No. 61-60272 with a solvent is prepared. Method obtained by coating on a quality support.

C. A solution obtained by mixing a polyorganosiloxane whose side chain ends are silanol-modified and a silane crosslinking agent or a siloxane crosslinking agent as shown in Japanese Patent Application No. 61-59269 is coated on a porous support. Method.

The thickness of the first thin film is preferably as thin as possible in terms of gas permeability, but an extremely thin film is not suitable in consideration of the occurrence of pinholes. According to the manufacturing method described above, it is possible to form a pinhole-free thin film up to a film thickness of about 0.1 μ, and therefore, a film thickness closer to 0.1 μ is preferable.

[Examples] The present invention will be described in more detail by the following examples.

The method for measuring the membrane performance and the method for evaluating the effect are as follows.

(1) Gas permeability, gas separability Oxygen permeability coefficient Po ₂ of membrane sample (dense film)
The nitrogen permeation coefficient PN ₂ and the separation coefficient α (= PO ₂ / PN ₂ ) were measured by using a gas permeability measuring device manufactured by Yanagimoto Manufacturing Co., Ltd.
It was measured at 25 ° C. by a reduced pressure method.

In addition, the performance of the composite membrane is that the pressure on the primary side is 2 atm, the pressure on the secondary side is 1 atm across the gas separation membrane, and the gas (oxygen or nitrogen) permeation rate is the precision membrane flow meter SF-101 (standard Technology Co., Ltd.).

Oxygen permeation rate (displayed as QO _2. Unit is m ³ / m ² · hr · at
m. ) Is the gas permeation performance, and the separation coefficient (denoted as α), which is the ratio of the oxygen permeation rate and the nitrogen permeation rate (indicated as QN ₂ ; the unit is m ³ / m ² · hr · atm.) It was used as the evaluation standard for the separation performance.

(2) Scratch resistance The gas permeability and gas separability of the gas separation membrane prepared according to the production method of the present invention are measured in advance, and the selective composite membrane is subjected to the Gakushin type robustness tester (Daiei Kagaku Seisei Co., Ltd.). Non-woven fabric MF-110 (manufactured by Japan Vilene) was used as a wear agent for 10 times, and the gas permeability and gas separation property after the test were measured to confirm the difference in performance before and after the test. It was used as an evaluation standard for scratch resistance.

Example 1 250 g of anhydrous xylene was added to poly (4-methyene) under a nitrogen atmosphere.
Le-1-Pentene (Mitsui Petrochemical Industry Co., Ltd. TPX M
25 g of X-001) was melted by heating. Trimethoxy in this solution
Add 50 g of vinyl silane and add benzoyl peroxide 1.2
After adding 5 g, the reaction was carried out at 110 ° C. for about 4 hours. Profit
The polymer obtained is reprecipitated twice from methanol.
The product is purified by vacuum drying.
Langraft poly (4-methyl-1-pentene) (I)
Got Silicon content of this graft polymer (I)
Was 0.13%.

10 g of the synthesized graft polymer (I) and 0.1 g of dibutyltin dilaurate were dissolved in 60 g of cyclohexane, and this solution was cast on a Teflon plate. Relative humidity about 70%
A crosslinked poly (4-methyl-1-pentene) film was obtained by drying at 40 ° C. for 8 hours under the above atmosphere. The oxygen permeability coefficient PO ₂ of this sample is 1.5 × 10 ^-9 (cm ³ · cm / cm ²
・ Sec ・ cmHg), nitrogen permeability coefficient PN ₂ is 3.6 × 10 ^-10 (cm ³
・ Cm / cm ²・ sec ・ cmHg) and separation factor α (= PO ₂ / PN)
₂ ) was 4.2.

Example 2 Methoxysilane-grafted poly (4 synthesized in Example 1
-Methyl-1-pentene) (I) and dilauric acid di-
10 mg of n-butyltin was dissolved in 200 g of cyclohexane. This solution was applied to a water-containing polysulfone porous support membrane that had only the water on the surface removed.
(M ³ / m ² · hr · atm)] is applied to the surface of the cross-linked poly (4-methyl-1-pentene) by dipping and then dried sufficiently with hot air at 140 ° C. A / polysulfone composite membrane was obtained. This composite membrane has an oxygen permeation rate (QO ₂ of 0.15 (m ³ / m ² · hr · atm), a nitrogen permeation rate QN ₂ of 0.042 (m ³ / m ² · hr · atm) and a separation coefficient α at room temperature.
(= QO ₂ / QN ₂ ) showed an oxygen enrichment performance of 3.6, and it was found that the crosslinked poly (4-methyl-1-pentene) had a good film-forming property.

Comparative Example 1 Poly (4-methyl-1-pentene) [Mitsui Petrochemical Co., Ltd.
Industry TPX MX-001, oxygen permeability coefficient Po₂ 1.7 x 10
^-9(cm³・ Cm / cm²・ Sec ・ cmHg) and α (= PO₂/ PN
₂) = 3.9] A solution of 1 g dissolved in 200 g cyclohexane.
In the same manner as in Example 2
) / Polysulfone composite membrane was prepared. This composite membrane
Separation coefficient α (QO₂/ QN₂) Is 1 and oxygen enrichment performance
Did not show.

Example 3 Water-crosslinked polypropylene (organic silane-modified polymer, three
Ryklon made by Ryoyu Kabushiki Kaisha P XPM800H) 1.4 g 70 ml
Dissolved in xylene at 140 ° C. Dibutyl in this solution
After adding 10 mg of tin dilaurate, cast it on the plate.
And translucent rack by drying at 130 ℃ and hot air drying.
A bridge polypropylene film was obtained. Oxygen permeability coefficient Po of this membrane₂
 1.7 x 10^-Ten(cm³・ Cm / cm²・ Sec ・ cmHg), separation factor α
(= PO₂/ PN₂) Was 3.4.

Example 4 A coating solution is prepared by diluting a primary solution prepared by dissolving 1 g (I) of the graft polymer synthesized in Example 1 in 99 g of cyclohexene with trifluorotrichloroethane to a polymer concentration of 0.1 wt%. In advance, using a polysulfone porous support membrane, according to the method of Example 1 of Japanese Patent Application No. 61-60272,
That is, 9.5 g of polydimethylsiloxane having silanol groups at both ends (number average molecular weight of about 50,000) and tetrakis (2
0.4 g of propanone oxime) silane and 0.1 g of dibutyltin diacetate are dissolved in cyclohexane to prepare a solution having a solid content of 0.5% by weight. A part of this diluted solution was coated on a polysulfone porous support, dried by heating at 130 ° C. for 1 minute, and then dried at room temperature for 1 hour to obtain a crosslinked siloxane composite film. In this way, a composite membrane is prepared in which the first thin film of crosslinkable silicone is provided on the porous support.
A coating solution of a graft polymer was applied to this composite film at a wet thickness of 20μ to obtain a selective composite film.

Table 1 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

Example 5 Poly (4-methylpentene-1) (Mitsui Petrochemical Industry
Co., Ltd. TPX MX-001) 25g heated to 250g anhydrous xylene
Dissolve, add 50 g of maleic anhydride, and add peroxide
After adding 1.25 g of Nzoyl, react at 110 ° C for about 4 hours.
became. The polymer obtained was reprecipitated from methanol to 2
After purification by repeating twice, vacuum drying is performed,
Maleic anhydride grafted poly (4-methylpentene-
1) (II) was obtained. The content of maleic anhydride is
Was about 3 mol%.

Polymer (II) 1 g was dissolved in cyclohexane 99 g to prepare a primary solution with trifluorotrichloroethane.
Prepare a coating solution by diluting it to 0.1 wt%. 100g of the coating solution, 1,3
-Add 0.1 g of bis (3-aminopropyl) tetramethyldisiloxane. In advance, a polysulfone porous support is used to prepare a composite membrane in which the first thin film of crosslinkable silicone is provided on the porous support according to the method of Example 4. Wet the thickness of 20μ with this composite film.
To obtain a selective composite film.

Table 1 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

Comparative Example 2 Poly (4-methylpentene-1) (Mitsui Petrochemical Industry
Co., Ltd. TPX MX-001) 1g dissolved in 99g cyclohexene
The prepared primary solution was polymerized with trifluorotrichloroethane.
-Prepare a coating solution by diluting it to a concentration of 0.1 wt%. Synopsis
Therefore, according to the method of Example 1 of Japanese Patent Application No. 61-60272,
First cross-linked silicone thin film provided on porous support
Prepare a composite membrane. This composite membrane has poly (4-methyl)
Apply Penten-1) coating solution with a wet thickness of 20μ and dry.
A selective composite membrane was obtained.

Table 1 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

From this table, it is understood that the selective composite membrane of the present invention is excellent in both gas permeability and scratch resistance.

Example 6 A selective composite film was obtained in the same manner as in Example 4 except that 0.1 g of tin octylate was added to the coating solution of the graft polymer (I) of Example 4.

It can be seen that the gas permeation performance and scratch resistance of the obtained selective composite membrane are improved.

Example 7 Ethylene propylene rubber (Mitsui Petrochemical Industry Co., Ltd.)
Made P-0180) 20 g was dissolved in 180 g of anhydrous xylene by heating.
Was. Add 50 g of triethoxyvinylsilane to this solution
Then, add 1.25 g of benzoyl peroxide at 110 ° C.
The reaction was carried out for about 4 hours. The obtained polymer is methanol
After reprecipitation was repeated twice, it was vacuum dried.
Dry and ethoxysilane-grafted ethylene propylene
I got a rubber (III). This graft polymer (III)
Had a silicon content of 0.3%.

A primary solution prepared by dissolving 1 g of the synthesized graft polymer (III) in 99 g of cyclohexane is diluted with trifluorotrichloroethane to a polymer concentration of 0.1 wt%, and 0.1 g of dibutyltin diacetate is added to prepare a coating liquid. JPA
According to the method of Example 1 of 60-257803, that is, Amino-modified siloxane represented by ▲ ▼ (number average degree of polymerization) = 1600 is dissolved in trichlorotrifluoroethane in an amount of 0.1 wt%, Isocyanate-modified siloxane represented by ▲ ▼ (number average degree of polymerization) = 1200 is dissolved in trichlorotrifluoroethane in an amount of 0.1 wt% and the two liquids are mixed at a ratio of 1: 1.
To prepare a coating solution. This coating solution is applied to the surface of the polysulfone porous support membrane, in which the pores have been impregnated with water, with a wet thickness of 25 μ, and 2 seconds after the application, it is dried with hot air at 100 ° C. The coating liquid is applied again with a wet thickness of 20 μm and dried under the same conditions. In this way, a composite membrane in which the first thin film of crosslinkable silicone is provided on the porous support is prepared in advance. A coating solution of the graft polymer (III) was applied to this composite film with a wet thickness of 20 μm and dried to obtain a selective composite film.

Table 1 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

Comparative Example 3 Ethylene propylene rubber (Mitsui Petrochemical Industry Co., Ltd.)
Made P-0180) 1g dissolved in 99g cyclohexane
Dilute the solution with trifluoroethane to a polymer concentration of 0.1 wt%.
Prepare a coating solution by pouring. In advance, according to the method of Example 7.
Therefore, the first thin film of crosslinkable silicone is formed on the porous support.
A composite membrane provided with is prepared. Ethylene in this composite membrane
Selective by applying a coating solution of propylene rubber with a wet thickness of 20μ
A composite membrane was obtained.

Table 1 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

Example 8 Poly (2,6-dimethyl-1,4-phenylene oxide) 6.
Dissolve 1 g in 400 ml of anhydrous tetrahydrofuran and at room temperature
N, N, N ', N'-tetramethylethylenediamine 8.5 ml and n
28 ml of n-hexane solution of -butyllithium (1.58M) was added, and the mixture was stirred for 80 minutes. Then, a mixture of 5.9 ml of trimethylchlorosilane and 1.3 ml of triethoxychlorosilane was added to this reaction solution, and the mixture was further stirred for 1 hour,
The obtained reaction solution was put into 2 of methanol, and the precipitated polymer was recovered by filtration. The polymer was purified again by reprecipitation with methanol and then dried under reduced pressure to obtain 7.4 g of a polymer [polymer (IV)]. In the infrared spectroscopic spectrum of this polymer, absorption derived from a trimethylsilyl group was observed at 1250 cm ⁻¹ , and further, according to a proton nuclear magnetic resonance spectrum, a trimethylsilyl group was contained in 25% of the repeating units and a trimethylsilyl group was contained in 4% of the repeating units. It was confirmed that a triethoxysilyl group was introduced into the.

After adding 1% tin octylate by weight to the 3% chloroform solution of this polymer, the solution was cast on a Teflon plate and left for 20 hours at 50 ° C and 80% RH to form a crosslinked film. did. Table 2 shows the separation coefficient and oxygen permeability coefficient of this crosslinked membrane.

Comparative Example 4 A 3% chloroform solution of the polymer (IV) synthesized in Example 8 was cast on a Teflon plate and then dried at 50 ° C. to form an uncrosslinked membrane. The separation coefficient and oxygen permeability coefficient of this uncrosslinked membrane are shown in Table 2.

Example 9 A primary solution is prepared by dissolving 1 g of the polymer (IV) synthesized in Example 8 in 99 g of trifluorotrichloroethane.
A diluting solution prepared by adding 0.02 g of tin octylate catalyst to 90 g of trifluorotrichloroethane is mixed with 10 g of the primary solution to prepare a coating solution having a polymer concentration of 0.1 wt%. Using the polysulfone porous support membrane, a composite membrane in which the first thin film of the crosslinkable silicone is provided on the porous support is prepared in advance according to the method of Example 4. A polymer coating solution having a wet thickness of 20 μ was applied to this composite film and then dried to obtain a selective composite film.

Table 3 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

Comparative Example 5 Poly (2,6-dimethyl-1,4-phenylene oxide) 6.
Dissolve 1 g in 400 ml of anhydrous tetrahydrofuran and at room temperature
N, N, N ', N'-tetramethylethylenediamine 8.5 ml and n
28 ml of n-hexane solution of -butyllithium (1.58M) was added, and the mixture was stirred for 80 minutes. Next, 6.0 ml of trimethylchlorosilane was added to this reaction solution, stirring was continued for an additional 1 hour, and the obtained reaction solution was poured into methanol 2 and the precipitated polymer was recovered by filtration. The polymer was purified again by reprecipitation with methanol and then dried under reduced pressure to obtain 7.0 g of a polymer [polymer (V)].

0.1 g of this polymer was added to trifluorotrichloroethane 9
Dissolve in 9.9 g to make a 0.1 wt% coating solution. According to the method of Example 4, a composite membrane in which the first thin film of crosslinked silicone is provided on the porous support is prepared in advance. A 0.1 wt% coating solution of a polymer [polymer (V)] is applied to this composite film as a W
The coating was applied at a thickness of 20μ to obtain a selective composite film.

Table 3 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

Example 10 1 g of the polymer [polymer (IV)] synthesized in Example 8 is dissolved in 99 g of cyclohexane to prepare a primary solution. Dilute 10 g of the primary solution with 90 g of trifluorotrichloroethane.
Prepare a 0.1 wt% coating solution. According to the method of Example 7, a composite membrane in which the first thin film of crosslinked silicone is provided on the porous support is prepared in advance. 0.1w for this composite membrane
A t% coating solution was applied with a wet thickness of 30μ to obtain a selective composite film.

Table 3 shows the gas permeation performance and the gas permeation performance after the scratch resistance test of the obtained selective composite membrane.

From this table, it is understood that the selective composite membrane of the present invention is excellent in both gas permeability and scratch resistance.

EFFECTS OF THE INVENTION The gas separation membrane of the present invention is excellent in gas permeability, gas selectivity, and has good membrane strength, film-forming property, and scratch resistance, and is more effective and economical with the membrane of the present invention. Gas separation is possible.

Claims (27)

(57) [Claims] 1. A thin film formed from a polymer selected from polyolefins and polyarylene oxides, which has an active functional group capable of self-crosslinking or reacting with a crosslinking agent to crosslink, and having a crosslinking bond. Characteristic gas separation membrane. 2. The gas separation membrane according to claim 1, wherein the polyolefin is a polymer mainly composed of an olefin having 2 to 18 carbon atoms. 3. The gas separation membrane according to claim 1, wherein the polyolefin is a polymer mainly composed of α-olefin. 4. The gas separation membrane according to claim 1, wherein the polyolefin is a polymer containing at least one selected from polypropylene and poly- (4-methylpentene). 5. The gas separation membrane according to claim 1, wherein the polyarylene oxide is a polymer represented by the following general formula. (However, in the formula, m is an integer of 1 to 3, n is an integer of 75 or more, R is each selected from an alkyl group, a substituted alkyl group, a phenyl group, a substituted phenyl group, a halogen atom, an alkoxy, an alkenyl group, and an amino group. The substituents are shown below.) 6. A polyarylene oxide is poly (2,6-
A polymer mainly consisting of dimethyl-1,4-phenylene oxide).
The gas separation membrane according to the item. 7. The polyarylene oxide, wherein the polyarylene oxide is a polyarylene oxide partially having a non-crosslinkable silicon group selected from an organosilyl group, an organosiloxane group and an organosylalkylene group. The gas separation membrane according to item 1. 8. The gas separation membrane according to claim 1, wherein the thin film is an asymmetric membrane. 9. A gas separation membrane, wherein the thin film according to claim 1 is present on a porous support. 10. Gas separation comprising a thin film of a polymer selected from polyolefins and polyarylene oxides having a cross-linking bond characterized by comprising an oligosiloxane bond, an amide bond or a carboxylic acid anhydride residue. film. 11. An oligosiloxane bond has the general formula [However, X ₁ , X ₂ , X ₃ , and X ₄ each represent a group selected from —OSi—, alkyl, aryl, alkoxy, acetoxy, oxime, and hydroxyl group, and n represents 1 to 3 or less. ]
11. The gas separation membrane according to claim 10, characterized in that 12. The gas separation membrane according to claim 10, wherein the polymer crosslinked by an oligosiloxane bond is a crosslinked polymer having an active silyl group. 13. An active silyl group is an alkoxysilyl group,
At least one selected from acetoxysilyl group and oximesilyl group.
The gas separation membrane according to item 12. 14. The gas separation membrane according to claim 10, wherein the polyolefin is a polymer mainly composed of an olefin having 2 to 18 carbon atoms. 15. The gas separation membrane according to claim 10, wherein the polyolefin is a polymer mainly composed of α-olefin. 16. The gas separation membrane according to claim 10, wherein the polyolefin is a polymer containing at least one selected from polypropylene and poly (4-methylpentene). 17. The gas separation membrane according to claim 10, wherein the polyarylene oxide is a polymer represented by the following general formula. (However, in the formula, m is an integer of 1 to 3, n is an integer of 75 or more, R is each selected from an alkyl group, a substituted alkyl group, a phenyl group, a substituted phenyl group, a halogen atom, an alkoxy, an alkenyl group, and an amino group. The substituents are shown below.) 18. The polyarylene oxide is poly (2,6).
-Dimethyl-1,4-phenylene oxide).
The gas separation membrane according to item 10. 19. The polyarylene oxide, wherein the polyarylene oxide is, in part, a non-crosslinkable silicon group selected from an organosilyl group, an organosiloxane group, and an organosylalkylene group. The gas separation membrane according to item 10. 20. The gas separation membrane according to claim 10, wherein the thin film is an asymmetric membrane. 21. A gas separation membrane, wherein the thin film according to claim 9 is present on a porous support. 22. Formed by evaporating a solvent from a solution prepared by dissolving a polymer selected from a polyolefin and a polyarylene oxide, which has an active functional group capable of self-crosslinking or reacting with a crosslinking agent to crosslink, in a solvent. A method for producing a gas separation membrane, wherein the thin film has a cross-linking bond. 23. The method for producing a gas separation membrane according to claim 22, wherein the solution contains a crosslinking agent that reacts with the active functional group. 24. The production of a gas separation membrane according to claim 23, wherein the solution contains at least one crosslinking catalyst selected from organic tin, carboxylate, amine and titanate. Method. 25. The method for producing a gas separation membrane according to claim 22, wherein the active group is an active silyl group, and the reaction is carried out in the presence of water when cross-linking. 26. A polyolefin or polyarylene having a first thin film made of a polymer having excellent gas permeability on at least a porous support and an active functional group capable of self-crosslinking or reacting with a crosslinking agent to crosslink. From a solution of a polymer selected from oxides dissolved in a solvent, the solvent is evaporated,
A gas separation membrane, wherein the formed thin film is formed by laminating a second thin film having a cross-linking bond composed of oligosiloxane bonds. 27. The method according to claim 26, wherein the first thin film is a crosslinked polyorganosiloxane.
The gas separation membrane according to the item.