JPH01143620A - Selective gas-permeable complex membrane - Google Patents

Abstract

PURPOSE:To improve both gas permeability and gas separability, by forming the lowermost layer of gas-separable membrane layers using glassy high polymers having a glass-transition temperature of 200 deg.C or higher, and providing a layer of phthalocyanine or a coordination complex thereof on the surface of a porous support body. CONSTITUTION:The lowermost layer of gas-separable compound membrane layers is formed using glassy high polymers having a glass-transition temperature of 200 deg.C or higher, such as polyphenylene oxide, acetylene high polymer etc., while a layer of phthalocyanine or a coordination complex thereof, e.g. being 10-2,000Angstrom in thickness, is provided on the surface of a porous support body made of polyether sulfone etc. In this manner, both gas permeability and gas separability can be improved compared with where a phthalocyanine layer is not provided. For example, oxygen permeating rate is raised from ca. 0.6X10<-1> to ca. 1.0X10<-1>cc/cm<2>.sec.atm and O2/N2 separation coefficient from ca. 4.0 to ca. 4.5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a selective gas permeable composite membrane used to separate and concentrate a specific gas from a gas mixture.

BACKGROUND OF THE INVENTION In recent years, methods of using polymer membranes having selective gas permeability to separate and concentrate specific gases from mixed gases have been actively researched and put into practical use. Examples include helium extraction from natural gas and recovery of hydrogen gas from factory exhaust, but the technology to selectively permeate oxygen from the atmosphere to create oxygen-enriched air has a wide range of applications and various The impact on industry, such as chemical processes, sludge treatment, combustion systems, and medicine, is extremely significant. The characteristics required of a polymer membrane used in such technology are that it has both high selectivity for the gas to be separated and high gas permeability.

Problems to be Solved by the Invention Among currently known polymers, polytrimethylsilylpropyne (PM) has particularly excellent gas permeability.
SP), the oxygen permeability coefficient of Pot is 1.60X 10
”Cl knee cm/C4・see 0cmHg, Siriyo 7go.

So Pot is ~6. OX 10 cc/cm/crt
i -5ee ・cyHg, etc., but the separation number α (PoV/PN*)id of these oxygen and nitrogen is about 1.
4 The latter is only about 2.0. On the other hand, there are many polymeric materials with large separation coefficients, but they all have poor gas permeability.For example, polyphenylene oxide has a large α of about 4.0, but Po is 2.8×101J:・crIV/c
Extremely low rd/saw/saw Hg. In general, gas permeability and gas selectivity of polymer membranes are in a relationship such that as one increases, the other decreases, and selective gas permeable composite membranes are capable of separating large quantities of specific gases at high concentrations. It was strongly requested.

In addition, such a membrane does not show small changes in gas permeation characteristics over time. When the PMSP is made into an ultra-thin film with a film thickness of ~0.1 μm, it begins to deteriorate immediately after film formation, and the gas permeation rate decreases to one-tenth when the film is about ten minutes thick, making it extremely unstable. The reason for this is said to be that the structural relaxation phenomenon characteristic of glassy polymers causes changes in the gas permeability properties of the polymers, and similar phenomena occur in other glassy polymers such as polyphenylene oxide, polysulfone, etc. It is also observed in

The present invention solves the above-mentioned problems and aims to provide a selective gas permeable composite membrane with excellent gas permeability and gas separation properties.

Means for Solving the Problems The present invention provides a permeable membrane having selective gas permeability, at least the bottom layer of which is made of a glassy polymer having a glass transition temperature of 200° C. or higher, and a porous support supporting the permeable membrane. The above object is achieved by an optional selective gas permeable composite membrane having a layer of phthalocyanine or a phthalocyanine coordination compound on the surface of the body.

Function The selective gas permeable composite membrane of the present invention has an oxygen permeation flow rate (Fo,
) is 4. OX 10~7.2X10'(cr:/cr
A・Formula・atm) Fo of the polyorganosiloxane copolymer that we have developed, ~1.5X 1
6" (ct/crl+-5ec-atm), the permeability can be about twice or more.

Further, the separability α (Fox/FN snow) increases to 30 to 5.0. In this way, it was discovered that the present invention is capable of improving separation performance without significantly reducing the permeability of the material itself as an initial property, and that the present invention is a highly selective gas permeable composite membrane. did.

The supports used in the present invention include porous supports prepared by various methods such as extraction methods, phase separation methods, and stretching methods (e.g., cellulose membranes, Teflon porous membranes, polypropylene porous membranes, polyethylene porous membranes). , polysulfone porous membranes, polyethersulfone membranes, polycarbonate porous membranes, etc.), non-woven fabric supports, etc., but in the composite membrane of the present invention, polysulfone and polyethersulfone-based support membranes have shown very good results. Indicated. Phthalocyanine or a phthalocyanine coordination compound is suitable for the layer to be formed on the surface of the support, and the forming method is to create an LB film of these compounds by vacuum evaporation, impregnation, or water surface development, and then adhere it. Examples include methods. The thickness of this layer is preferably 10A0 to 200OA'.

The polymer having a glass transition temperature of 200°C or higher used in the present invention has the general formula % [wherein R1 is selected from the group consisting of a hydrogen atom, a C1 to S alkyl group, or a halogen atom, and R2 is CI to・
an alkyl group, (γ" (X is a hydrogen atom, an alkyl group of C..., or a halogen atom) CH.

Suitable are acetylene polymers selected from the group consisting of ), polyphenylene oxide, aromatic polysulfone, polyfumaric acid ester, and the like.

In order to produce these thin films, a water surface development method is suitable, in which a dilute solution of these molecules is prepared and the solution is dropped onto the water surface to form a solid film.
2000 A' is preferred. Composite formation can be accomplished by attaching the glassy polymer membrane to a support provided with a surface layer of phthalocyanine or a phthalocyanine coordination compound as described above.

In addition, in order to further impart functions such as antifouling, moisture proofing, and antistatic properties to the composite membrane produced in this manner, a layer that does not impede gas permeability is overcoated, but the present invention is not limited to this. do not have.

<Example-1> Polyether sulfone (manufactured by Toyo Cross Co., Ltd.) was used as a porous support, and phthalocyanine iron was heated to 430° C. and vapor-deposited for 3 minutes in a vacuum of 10 TO. Next, a 1we% toluene solution was prepared using polytrimethylsilylpropyne (PMSP) as a glassy polymer, and this was developed on ion-exchanged water to obtain an ultra-thin film with a thickness of ~01 μm. This ultra-thin film is attached to the support,
When the gas permeation rate was measured using a bubble flowmeter,
The oxygen permeation rate Fog is ~7. I x 10”CtlC
rd ``56 ('' atm), the oxygen/nitrogen separation coefficient α was obtained with a value of about 32. On the other hand, in a membrane similarly composited using a support without evaporated iron phthalocyanine, Fog ~3
．． 8 X 10' Ct/crA-see・atm
, only α ~ 2.8 was obtained. Thus, it can be seen that in this example, the separability can be significantly improved without reducing the oxygen permeability.

<Example-2> When polyphenylene oxide (PPO, Mw of 150,000) was used as the glassy polymer in Example-1 and a composite film was formed in the same manner, the surface was coated with hydrogen silane. ~1. OX 10α/cn1・
Initial characteristics of the formula atm, α~4.5, were obtained. On the other hand, for a composite membrane without a phthalocyanine layer, Fog ~ 0.6X 10
ct/crtt-see-atm, α~4.0.

Effects of the Invention The present invention provides that at least the lowermost layer of a permeable membrane having selective gas permeability is made of a glassy polymer having a glass transition temperature of 200°C or higher, and that the surface of the porous support supporting the permeable membrane is This product provides a selective gas permeable composite membrane equipped with a layer made of talocyanine or phthalocyanine coordination compound, and is a high-performance gas permeable membrane with superior gas permeability and gas separation performance compared to conventional gas permeable membranes. It is.

Claims (4)

[Claims] (1) At least the bottom layer of the permeable membrane having selective gas permeability is made of a glassy polymer having a glass transition temperature of 200°C or higher, and phthalocyanine or a phthalocyanine coordination compound is added to the surface of the porous support supporting the permeable membrane. A selective gas permeable composite membrane comprising a layer consisting of: (2) Glassy polymer has general formula ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (3) The selective gas permeable composite membrane according to claim 1, wherein the glassy polymer is polyphenylene oxide. (4) The selective gas permeable composite membrane according to claim 1, wherein the glassy polymer is aromatic polysulfone.