JPS61107922A - Composite membrane for gas separation - Google Patents

Abstract

PURPOSE:To obtain a composite membrane having excellent gas permeability and selective permeability by laminating a siloxane compound layer and a gas separating polymer layer on an arylacetylene polymer and a porous support layer. CONSTITUTION:A siloxane compound consisting of polysiloxane as a main chain is laminated on an arylacetylene polymer layer having a constitution unit as shown in the formula I (X in the formula represents the methyl group or the Cl group and Y represents hydrogen atom, the methyl group or the Cl group). The siloxane compound contains 50% or more of dimethyl siloxane unit with a molecular weight of 5,000-1,000,000. On the siloxane compound, a polymer having gas separability is laminated. Substituted acetylene polymers such as notrimethyl sirylpropyne and poli(4-methylpentane-1) are used as such polymers. The support layer is 0.001-10mm thick, the siloxane compound layer 10-2,000Angstrom and the gas separating polymer layer 50-1,000Angstrom .

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a composite membrane for gas separation.

[Conventional technology]

In recent years, a method using a polymer thin film as a means for separating and concentrating a specific gas from a gas mixture has been attracting attention.

Conventionally, composite membranes for gas separation have been known in which thin films such as alkyl group-substituted acetylene polymers, arylacetylene polymers, l-monoakyl dimethyl silica propyl polymers, etc. are combined with supports such as porous polypropylene. (For example, Japanese Patent Application Laid-Open No. 52-22i05-9,
Japanese Patent Application Laid-Open No. 59-19506 and Japanese Patent Application No. 58-29
786 Specification).

[Problem that the invention seeks to solve]

The inventors of the present invention have conducted extensive studies in the above-mentioned technology in order to obtain a composite membrane for gas separation that has good gas permeability and permselectivity and can maintain these performances more stably. Reached.

[Means for solving the problem] The present invention provides an arylacetylene polymer having a structural unit represented by the general formula (wherein X is a methyl group or a C6 group, and Y is a hydrogen atom, a methyl group, or a Cl group). A porous support layer consisting of (
This is a composite membrane for gas separation characterized by having A), a siloxane compound layer (B) thereon, and a polymer layer (C) having gas separation properties thereon.

The siloxane compound forming the siloxane compound layer has the general formula (wherein R is at
-ts is a non-reactive group such as an alkyl group, phenyl group or fluoroalkyl group, preferably a methyl group: X is a hydrogen group, a vinyl group, a hydroxy group, a hydroxy group
Kyl group, aminoalkylμ group 1-boxy7ρkiρ group, C
Reactive groups such as L group, chloro7ρ group, glycidoxy/L/ group, methacryloxyalkyl p group to mekabutofurki μ group; Y and 2 are general or reactive groups X, and m is 1 In the above, n is 0 or 1 or more), the general formula, and a crosslinking reaction product consisting of one or a mixture of two or more thereof.

In general formulas (3) and (4), the alkyl group of Ct-18 is methyl, ethyl, hexyl ρ, octyl, decyl, octadecyl μ group, etc., the fluoroalkyl group is p, the hydroxyalkyl group is -CHICH, C C0O
H, etc. Fluoroalkyl groups include -(A, C6, etc.; glycidoxyalkyl ρ groups include -CH, CH, CH
20CH.

teeth CH.

-CH, CH, CH, -00QJ= CH, etc.
The siloxane units without cubedoric groups may be randomly distributed.

Also has a siloxane part and a non-siloxane part in the main chain,
Compounds can also be used. Specifically, the following can be mentioned.

(1) Polydimethylsiloxane-kylene oxide copolymer U=O or CH.

f=H or CHl (11) polytetramethyldisiloxane-ethylene copolymer (1), if polydimethylsiloxane-silphenylene copolymer (1v) polydimethylsiloxane--methylstyrene (v) polydimethylsiloxane-bispheno-) vA carbonate The amount of dimethylsiloxane units in the block copolymer siloxane compound is usually at least 50 units, preferably at least 70 units.

If the amount of dimethylsiloxane units is less than 50 units, the gas permeability of the composite membrane will be insufficient.

The molecular weight of the siloxane compound is usually 5,000 to 1,000,000,
Preferably it is 50,000 to 500,000. If the molecular weight is less than 5,000, the gas separation performance and durability of the composite membrane will decrease and
If it exceeds 1,000,000, it becomes difficult to form a thin film.

Preferred siloxane compounds are (a), t'
Ridimethy 1v70xane, (b)dimethylsiloxane-
(0,5-7,5-thi)methylvinylsiloxane copolymer.

(c) dimethylsiloxane-(8-7th) diphenylsiloxane-(0,5-t,o%) methylvinylsiloxane copolymer, di)methy/l/-8,3,8-trif 0
Robcopi ρ siloxane-(1-2)methylvinylsiloxane copolymer, (v)dimethylsiloxane-(24
~27%) methylphenylsiloxane-(o, 2-0.
5%) Methylvinylsiloxane copolymer, (to)
Diphenyl-dimethylsiloxane copolymer terminal vinyl/L/.

(G) Polydimethylsiloxane-terminated vinyl, (2) Polydimethylsiloxane-terminated H, (S) Dimethyl-(3-50
%) Methylhydrosiloxane coprimer, and (g) a crosslinking reaction product consisting of two or more of the above, such as middle) a crosslinking reaction product of the same, and a crosslinking reaction product of (b) and example or (s).

and a crosslinking reaction product of (g) and (g) or (su).

Among these, the preferred ones are (a), (b) and (
).

The arylacetylene monomer forming the structural unit of general formula (1) is pheny/I/acetylene (2-
Methyl A/-1-) uniy acetylene), halophenylacetylenes [2-chloro-1-phenylacetylene, 2-chloro-1-(/thiρphenyρ)7 cetelene, 2
-chloro-1-(chlorophenyl)acetylene, 2-methyl-1-(chlorophenyl A/)acetylene, etc.).

Among these five, preferred are 2-chloro-1-phenylacetylene and 2-methyl-1-phenylacetylene.

The arylacetylene polymer is composed of the above monomer and 7 described below.
/I/ki/l/7 cetylene monomer and h/mata are 1-
It may also be a copolymer of monoalky p-dimethyρ-sili-propyne.

In this copolymer, the content of the 7-ary ρ7 ceterene monomer is usually 50% by weight or more, preferably 70% by weight or more of the total monomers. Alternatively, it may be a mixture with l-monoalkyldimethylsilyl ρ◇vin polymer.

In this mixture, the content of the aryl acetylene polymer is generally 50 i fi methane and preferably 70 methyl or more by weight in the mixture.

The arylacetylene polymer is a pale yellow to white fibrous or powdery solid. Its molecular weight is usually 10,000 or more, preferably 10,000 or more in weight average molecular weight (light scattering method).

Regarding alkyl acetylene polymers, patent application No. 57-1
It is described in the specification of No. 28376 and the specification of Japanese Patent Application No. 59-87207.

Examples of polymers forming the polymer layer having gas separation properties include substituted acetylene polymers, α-olefin polymers [poly(4
-Methylpentene-13fi,! ”), vinyl organosilane polymers (polymers such as vinyl trimethy μsilane 1 vinyl to triethyl/L/7 runs, vinyltripropy/I/7 runs, preferably vinyltrimethylsilane polymers),
Cellulose polymers (ethyl cellulose, hydroxyethyl cellulose, triacetyl cellulose, etc., preferably ethyl cellulose), alkyl sulfone polymers (α
- Copolymer of olefin and SO2, preferably with 1 carbon number
0 to 20 long-chain a-p-phone polymers, etc.), the third
grade amine-containing polymer (vinyl pyridine polymer, N-N-
diethylaminomethyl acrylate polymer, N,N-dimethylaminostyrene polymer, preferably vinylpyridine polymer), polyvinyl alcohol, polyethylene terephthalate, polystyrene, poly(vinyldimethylaminobenzaceter/L/) to aliphatic amino-containing Examples include polyurethane.

Among these, substituted acetylene polymers and poly(4-methylpentene-1) are preferred in terms of film-forming properties, gas permeability, and permselectivity.

Examples of substituted acetylene polymers include single polymers (homopolymer, copolymer) (general formula: hydrogen atom, methyl group, or Cj group) and mixtures of two or more types of polymers.

In the general formula (2), the alkyl group from C1 of melon to snow includes a linear or branched alkyl group (methyl, ethyl, n- or tertiary-buty/L/ group, etc.).

The alkyl group of bird ct-m is linear alkyl/V
Groups such as methyl, methyl, butyl, hexyl, octyl, decyl, dodecyl, hexadecyl and branched alkyl groups such as tert-butyl, 2-methylpropyl, 8-methylpropyl, 2-methylbutyl , neopentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-ethylhexyl, and the like.

As the alkyl group of C-1t, straight-chain alkyl groups (methyρ, ethyl, propyρ, butyl, pentyl, hexyl, hebutyl, octyl, nonyl, deci/L/%
(dodecyl group, etc.): Branched alkyl group (isobuty μ group, tert-buty p group, etc.); Examples of 8i-containing alkyl group (alkyl group is C1-4) include trimethylsilylmethyl group, trimethylsilylethyl group, etc. .

The polymer consisting of the structural unit represented by the general formula (2) has 1
- Monoacrylic p dimethylsilylpropyne polymers, arylacetylene polymers and alkyl acetylene polymers.

l-7noa ~ Ki ρ dimethe ρ sili〃 L-monoalkyl dimethy constituting the propyne polymer! Examples of resilylbropine include 1-trimethylsilylpropyne, 1-mono n-propyp dimethyp silyl lepropine 11-mono 〇-hexyp dimethyl 7 lylpropyne 1-()limethylsilyl silyl) methyl l dimethyp #-1-propyne% 1 -()rimethersilyl)ethypdimethymusilyl/v-1-propyne and mixtures of two or more thereof.

Among these, 1-trimethylsilylpropyne is preferred.

As 1-trimethylsiliA/-1-propyne, a commercially available monomer (product of Betrak Co., Ltd. of the United States, product T1728 of SP Development Department of Chisso Corporation) can be used.

The arylacetylene monomer constituting the arylacetylene polymer includes 2-methyl-1-phenylacetylene, 2-chloro-1-phenylacetylene, 2-chloro-1-(methylphenylene/L/)acetylene, 2-chloro-o- Examples include 1-(chlorophenylacetylene/L/)acetylene, 1-(chlorophenyl)acetylene, and mixtures of two or more thereof. Among these, preferred are 2-chloro-1-phenylacetylene and 2-methyl-1-
It is phenylacetylene.

The alkyl acetylene monomers constituting the 7Iv x-acetylene polymer are 01~! Acetylene substituted with an alkyl group of 0 or an alkyl group of at-S, such as 1-alkyne (tertiary-butylacetylene, tertiary-benchi!acetylene, 4-methy/v-1-pentene, 3-methy/l /-1-pentyne, 1-hexyne, etc.)% 2-alkynes (2-hexyne, 2-octyne, 27synfx, etc.) and mixtures of two or more thereof.

Among these, the tertiary-butysubstituted acetylene polymer is preferably a white to pale yellow fibrous or powdery solid. Its molecular weight is usually 10,000 or more, preferably 100,000 or more, as measured by weight average molecular weight (light scattering method).

Regarding the l-mono7ρ-kyldimethylsili-μpropyne polymer, see Japanese Patent Application No. 1986-29786 and Japanese Patent Application No. 1983.
-87207, and 7-Li/I/acetylene polymer in Japanese Patent Application No. 57-128176 and 1987-87207, and 7ρ Kip acetylene polymer in Japanese Patent Application No. Nos. 58-223405 to 9 are described.

Among the substituted acetylene polymers, B is preferred.

(1-trimethyl-silylpropyne) and poly(2-
chloro-1-phenylacetylene).

As a method for forming the arylacetylene polymer into a porous support, the method described in JP-A-57-190607 and similar methods can be adopted. The dope is prepared by dissolving it in its main solvent (for example, aromatic hydrocarbons, logenated hydrocarbons, dioxane, N-methylpyrrolidone-tetrahydrocarbons, and mixtures thereof) to % by weight. The dope is applied onto a nonwoven fabric, a wire mesh, or a ceramic porous body, or the dope itself is immersed and coagulated from a hollow spinneret into a coagulation bath containing water or a non-solvent such as 7-coal, respectively, and then washed and dried. Porous supports can be obtained by this method.

The air permeability of a porous support made of an arylacetylene polymer is usually 1 to 100 @"/@' ・hr @ O
-1 atm (25°C) preferably 5 to 50rrL”/11
1"・hr・0.1 atm (25℃).If the air permeability is less than 1,S, the gas permeability of the composite membrane obtained using it will be too low, and if it exceeds Loom', it will be too low. The durability of the composite membrane obtained using the porous support is reduced.The thickness of the porous support is usually 0.001 to 10, preferably 0.01.
~1 dragon. If the thickness of the porous support is less than 0.001 m, the durability of the support will be insufficient, and if it exceeds 10 mm, the air permeability will be insufficient.

Preferably it is 100λ to 1000^. If the thickness of the siloxane compound layer is less than 1ooX, the durability of the obtained composite membrane will be reduced, and if it exceeds 2000^, the gas permeability of the obtained composite membrane will be insufficient.

Examples of methods for forming a thin film of a siloxane compound on a porous support include methods such as 1 ultrafiltration method 1 coating method 1 water spreading method, and a method of directly forming a thin film on the support using plasma polymerization method. It will be done. Among these, the water spreading method is preferable because it allows ultra-thin films to be uniformly laminated.

These siloxane compounds may be laminated on the support as they are, or may be laminated after crosslinking treatment.

Further, crosslinking may be performed after lamination. There are various methods for crosslinking siloxane compounds depending on the type of reactive group contained therein. For example, ■ peroxide (
Thermal crosslinking method using diazide (pencil peroxide, dicumyl peroxide, etc.) and diazide (2,6-bis(P-7didobenzylidene)cyclohexanone, etc.)
When the siloxane compound contains a vinyl group), ■(, /V
υV irradiation crosslinking method using an initiator (benzophenone, benzoinisobuty-etherp, etc.) and diazide (2,6-bis(P-azidobenzylidene)cyclohexanone, etc.) (when the siloxane compound contains a vinyl group), 0
Condensation crosslinking method using metal salts such as tin octylate and zinc octylate (when the siloxane compound contains condensable groups such as 5i-H and 5i-OR), ■ Addition using chloroplatinic acid Crosslinking (when the siloxane compound contains Si-H and the other compound contains an unsaturated bond such as a vinyl group), etc. can be used.

When crosslinking a siloxane compound, the molecular weight of the crosslinked product is preferably within the range of the molecular weight of the siloxane compound.

The film thickness of the polymer having gas separation properties which is laminated on the siloxane compound layer is usually 50.lambda. to 1000.times., and the permeability is preferably reduced, and if it exceeds 100.lambda., the gas permeability becomes insufficient.

A method for further layering a polymer with gas separation properties on a composite membrane consisting of a porous support made of an arylacetylene polymer and a siloxane compound layer is as follows: 1) Dissolving the polymer with gas separation properties in a solvent. Method of coating on a composite film: ■ Spreading on water method, in which the polymer is dissolved in a water-insoluble solvent and spread on the water surface to create a water surface film, which is then laminated on the composite film; ■ Plasma polymerization method is used. Examples include a method of directly forming a gas-separating polymer thin film on the composite membrane.

Among these, the water spreading method is preferable from the standpoint that uniform, defect-free ultra-thin films can be laminated.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Production Example 1 In toluene lj, 1 mmol of molybdenum pentachloride, 1 mmol of phenydimethylsilane was added, and 1.25 mmol of l-Funi/I/-2-chloroacetylene was added, followed by polymerization at 40°C for 24 hours. I let it happen. The obtained polymerization solution was diluted to 5 times the volume with toluene and poured into methanol, and the precipitate was dried in an oven to obtain yellow solid polyphenylchloroacetylene (PPCA).

The weight average molecular weight determined by light scattering method was 800,000.

This PPCA was dissolved in dimethylacetamide to a concentration of 10% by weight, and a nonwoven fabric (Nippon Vilene gMF
-so) It was applied to a thickness of 250μ using an overwriting applicator and immediately immersed in methanol to coagulate.

Thereafter, it was thoroughly washed and dried with a slight breeze at 50°C to obtain a porous support having an asymmetric structure. The gas permeability of this support was 32y1''/y1''·hr·0.1 ultimate pressure.

Production example 2 1-trimethylsilyl-1- in toluene loo ml
Propyne (T872g sold by Nitrogen SF Development Department) 0
．． 27~, add 1 mm of Ta1ls as a catalyst N!
Polymerization was carried out at T80°C for 24 hours. The obtained viscous polymer gel was diluted and dissolved with toluene and then poured into a large amount of methanol for purification. The poly(1-trimethy-sili/L/-1-propyne) (PMSP) obtained after drying separately in F was in the form of white fibers, and the weight average molecular weight determined by the 1-light scattering method was 140.
It was 10,000.

Example 1 After dissolving 1 g of dimethyl-methyρ vinylsiloxane copolymer (silicon gum SE [-410 manufactured by Toray Silicone ■) in 50 g of hexane, 0.33 rnJ of the solution was dropped and spread on the water surface. The obtained water surface film was laminated on the PPCA porous support obtained in Production Example 1. The thickness of the formed thin film was calculated from the area of the water surface film and the weight of the dropped 5H-410 to be 50OA. .

Next, PMSPlg obtained in Production Example 2 was added to 100 g of hexane.
0.2 ml of the solution was dropped onto the water surface to obtain a water surface film. This film thickness was calculated as above and found to be 100A. This PΔfsP water surface film is
A composite membrane was obtained by laminating it on a 410 Seireki membrane. The gas permeability of the obtained composite membrane was measured using oxygen and nitrogen. The results are shown in Table-1.

Example 2 2 ml of the 5H-410 solution o from Example 1 was dropped and spread on the water surface. The thickness of the obtained water surface film was 300λ.
After collecting on the PPCA porous support prepared in IJ Preparation Example 1, an FMS P water surface membrane was laminated in the same manner as in Example 1 to obtain a composite membrane. Table 1 shows the measurement results of gas permeability.

Example 8 Poly(4-methylpentene-1) II was dissolved in 100 g of cyclohexene and a water surface film with a film thickness of 200 A was obtained by the water spreading method.
This water surface membrane was laminated on the 410 laminated membrane to obtain a composite membrane. Table 1 shows the measurement results of gas permeability.

Example 4 Methane and C
The permeation rate of methane gas and carbon oxide, which measured the gas permeation performance of Ot, is QCH4 = 28 m"/m'・h
r-atm, QCo2=114TrL”/1rL!
・hr @atm, and the value hardly changed even after continuous measurement for one month.

Comparative Example 1 A composite membrane was obtained in the same manner as in Example 1, except that porous polypropylene (Duraguard 2400 manufactured by Celanese) was used as a support instead of PPCA.

The electrical transmission performance is shown in Table 1.

Comparative Example 2 A 100A thick FMS P water surface film was obtained in the same manner as in Example 1. This was directly laminated on the PPCA porous support obtained in Production Example 1. Table 1 shows the gas permeability of the composite membrane obtained.
Shown below.

Comparative Example 8 A composite membrane was obtained in the same manner as in Example 1, in which a 500A thick 5Ti-410 water surface membrane was laminated on a PPCA porous support.

When the gas permeation performance of the obtained composite membrane was measured, it showed no gas separation property at all.The measurement results are shown in Table 1.

Table-1 1) Oxygen permeation rate (m777L' -hr-atm)2
) Separation coefficient (QO!/QN2) [Effects of the invention] The composite membrane for gas separation of the present invention has 1 good selective gas permeability (
For example, the separation coefficient between oxygen and nitrogen Q02//QN2=2.
0 to 4.0) while maintaining excellent gas permeability (for example, oxygen permeation rate Q02 = 5 to 501rL3/m2・h)
r-atm). Moreover, these performances can be maintained more stably. For example, the stability of the oxygen permeation rate and separation coefficient of the composite membrane of the present invention is extremely superior compared to when porous polypropylene is used as the support or when no siloxane compound layer is provided in between.

Since the composite membrane of the present invention exhibits the above effects, it can be preferably used as an oxygen-enriching membrane, but it has a high permeability not only for oxygen but also for gases in general, so it is less permeable to other mixed gases than other mixed gases. i% For example, separation of carbon dioxide/methane in biogas, separation of hydrogen/nitrogen and hydrogen/carbon oxides, which are of great interest in the chemical industry 1. Concentration of helium from natural gas 1. Hydrocarbon procedures Amendment Book November 1982 Patent a (1) filed on October 30, 1980 by the Director of the Japan Patent Office (1st), Patent a (1) 2, Title of the invention: Composite membrane for gas separation 3, Spontaneity of the person making the amendment 5, Expansion of the invention due to the amendment "Example IJ" on page 24, 3F, line 2 of the specification is replaced with "Example 3"
” he corrected.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, X is a methyl group or a Cl group, and Y is a hydrogen atom, a methyl group, or a Cl group.) It has a porous support layer (A) made of an arylacetylene polymer having a structural unit represented by the above, a siloxane compound layer (B) thereon, and a polymer layer (C) having gas separation properties thereon. A composite membrane for gas separation characterized by: 2. The composite film according to claim 1, wherein (B) has a thickness of 100 Å to 2000 Å. 3. The composite film according to claim 1 or 2, wherein the thickness of (C) is 50 Å to 1000 Å. 4. (B) contains 50 dimethylsiloxane units in the polymer
The composite membrane according to any one of claims 1 to 3, which is a polyorganosiloxane containing % by weight or more. 5. The composite membrane according to any one of claims 1 to 4, wherein (B) has a molecular weight of 5,000 to 1,000,000. 6. Polymers with gas separation properties have the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (2) [In the formula, R_1 is a hydrogen atom, C_1_-_5 alkyl group or Cl group; R_2 is C_1_-_2_0 alkyl There are groups, ▲ mathematical formulas, chemical formulas, tables, etc. ▼ (where X is a hydrogen atom, methyl group, or Cl group), ▲ mathematical formulas, chemical formulas, tables, etc. ▼ (R is an alkyl group of C_1_-_1_2, or Si Claim 1 is a substituted acetylene polymer having a structural unit represented by [containing alkyl group)] or poly(4-methylpentene-1).
The composite membrane according to any one of Items 1 to 5.