JPH01176424A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To improve the reliability of a thin film by using as a material of a gas separation membrane, a copolymer of p-vinyl phenol and styrene and a copolymer of polysulfone and polysiloxane. CONSTITUTION:As a material of a gas separation membrane, a copolymer of p-vinyl phenol and styrene represented by the formula I and a copolymer of polysulfone and polysiloxane are used. In such constituting, by partially replacing copolymers represented by the formula I by trimethylsilylated polyhydroxy styrene, said material for the gas separation membrane becomes such a material as is hardly subjected to hydrolysis, becoming chemically stable, leading to improved reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a gas separation membrane for separating and concentrating gases.

2. Description of the Related Art In recent years, methods using thin polymer films have been attracting attention as a means of separating and concentrating specific gases (oxygen, nitrogen, etc.) from mixed gases (air, etc.). Gas separation membrane materials include polymethylsiloxane and poly(4-methylpentene-1).
, polysulfone.

Examples include polystyrene and polyphosphazene. In particular, polymers mainly composed of polysiloxane, which has excellent gas permeability, are used as oxygen-enriching membrane leaf materials for combustion. In consideration of film strength and film formability, polymers have been developed in which polysiloxane segments are reinforced with hard segments. Examples include block copolymers of polysiloxane and polycarbonate, or crosslinked copolymers (especially Kaisho 56-26506
) etc.

Problems to be Solved by the Invention The permeability coefficient of oxygen gas in a membrane made of a copolymer of polysiloxane, polysulfone, and partially trimethylsilylated polyhydroxystyrene (Japanese Unexamined Patent Publication No. 56-26506) is 2.0x10. '(d-d/d・formula・mHg) is on the same order as the polysiloxane membrane, so the separation coefficient is
From 2.1 to 2.2, in terms of the formability of the thin film and the strength of the film in the thin film state, it is significantly improved compared to the polysiloxane film. However, the copolymer of polysiloxane, fluorinated polysulfone, and partially trimethylsilylated polyhydroxythrene has improved gas separation, with a separation coefficient of 2.2 to 2.3. However, the reliability of the thin film is unsatisfactory.

In view of the above drawbacks, the present invention aims to improve the reliability of thin films.

Means for Solving the Problems In order to achieve this object, the gas separation membrane of the present invention has p-
It is composed of a copolymer of vinylphenol and styrene, a copolymer of polysulfone, and a polysiloxane.

Effect In the above structure, by using a copolymer of p-vinylphenol and styrene in place of 9, which is less susceptible to hydrolysis.
, chemically stable. Therefore, this siloxane copolymer is chemically stable and reliability is improved.

EXAMPLES Next, the present invention will be explained in more detail based on examples.
The content of the present invention is not limited only to the following examples.

[Example 1] Polysulfone (My Misaki 1o00o) 6q and linker-1
5 (manufactured by Maruzen Petrochemical ■), 210 yttl of chlorobenzene, and 150 yttl of 1,4 dioxane. Dissolved in a mixed solution of
Add 13p of α,W bis(diethylamino)polydimethylsiloxane (Mw'====2500) to this.
Add. After the addition, the mixture is reacted at 90°C for about 1 hour, and the temperature is further raised to 110°C for about 1 hour. After the reaction is completed, the mixture is cooled to room temperature and poured into a large amount of methanol to obtain a reaction precipitate. The reaction precipitate was purified by a reprecipitation method and then vacuum dried to produce a purified copolymer (hereinafter referred to as Polymer H).
3) was obtained.

Polymer H3 is made into a 2 wt % benzene solution, and 3 wt % tetrahydrofuran is added to this solution to obtain an adjusted solution. When this solution was thinned on the surface of water, a nearly transparent, uniform, ultra-thin film was obtained. The membrane thus obtained was adhered onto porous polypropylene (Duraguard 2400, manufactured by Polyplastics).

The film thickness was 0.1 μm or less. The permeability coefficients of oxygen and nitrogen were determined by leaving the membrane in a humidity-resistant tank at a temperature of 60°C and relative humidity of 95%, and taking it out from the tank every 100 hours to measure the separation coefficient ct (02/PN2) of the membrane. As a result, 1
It was not until 600 hours had passed that α fell below 2.0.

[Example 2] Fluorinated polysulfone (Mw Misaki 1oooo) sy, Linker-15 (manufactured by Maruzen Petrochemical ■) 2.5f, chlorobenzene 210rrtl, and 1,4 dioxane 1rs
Dissolve in a mixed solution of oml and stir at 70° under star two stirring.
C. and add α, W bis(diethylamino)polydimethylsiloxane (Mw→2500) i132. After the addition, the mixture is reacted at 90'Q for about 1 hour, and the temperature is further raised to 110° C. for about 1 hour. After the reaction is completed, the mixture is cooled to room temperature and poured into a large amount of methanol to obtain a reaction precipitate. The reaction precipitate was purified by the reprecipitation method and vacuum dried to obtain a 41m copolymer (hereinafter referred to as Polymer H8).
(call it F). When this adjustment solution was applied to form a +4 film on the water surface, a nearly transparent and uniform ultra-thin film was obtained. The membrane thus obtained was made of porous polypropylene (Duragard 2).
400. (made of polyplastic). The film thickness was 0.1 μm or less. Membrane separation coefficient α (PO2/
PN2] was 2.3. This film is heated at a temperature of θo'C
, leave it in a humidity-resistant tank with a relative humidity of 96%, and remove it from the oak every 100 hours to determine the separation coefficient α (Po2/PN2
), it was found that α did not change after 2000 hours.
2. Of, I went down.

[Comparative Example 1] Fluorinated polysulfone (Mw4Q1oooo)s
S' and 86% trimethylsilylated polyhydroxystyrene 2.5 f t-chlorobenzene 21011t
Dissolved in a mixed solution of 150 m/l and 1,4 dioxane,
Heat to 70'C under Starcy stirring and add (E,
W bis(diethylamino)polydimethylsiloxane (M
waq2500) Add f 139k. After addition 9
React at 0'C for about 1 hour, then raise the temperature further to 110
Allow to react for about 1 hour at °C. After the reaction is completed, the mixture is cooled to room temperature and poured into a large amount of methanol to obtain a reaction precipitate.

After purification by a reaction precipitation method, a purified copolymer was obtained by vacuum drying. A 2 wt % benzene solution was prepared from this co-merged product, and 3 wt % tetrahydrofuran was added to this solution to obtain an adjusted solution.

When this solution was thinned on the surface of water, a nearly transparent, uniform, ultra-thin film was obtained. The membrane thus obtained was deposited on porous polypropylene (manufactured by Duragard 2400° Polyplastic@). The film thickness was 0.1 μm or less. The separation coefficient α (PO2/PN2) was 2.3. This membrane was left in a humidity-resistant tank at 60°C and 95% RH, and was removed from the cypress every 100 hours to remove the membrane's separation coefficient α (
When measuring PO2/PN2), α
has fallen below 2.0.

[Comparative Example 2] Polysulfony/ (Mw b-p 10000) 5
f and 40%) dimethylsilylated polyhydroxystyrene 2.62 was dissolved in a mixed solution of chlorobenzene 21 om/ and 1y4 dioxane 150111/ and heated to 70'C under stirring with a stirrer. diethylamino) polydimethylsiloxane (Mwk-P250
0) Add tl”132 Approximately 1 at 90°C after addition
Allow time to react. After the reaction is completed, the mixture is cooled to room temperature and poured into a large amount of methanol to obtain a reaction precipitate. The reaction precipitate was purified by a reprecipitation method and then vacuum dried to obtain a purified copolymer. This copolymer 12wt'Q is made into a benzene solution, and 3wt% of tetrahydrofuran is added to this solution to obtain a liquid preparation A. When this solution was thinned on the surface of water, a nearly transparent, uniform, ultra-thin film was obtained. The membrane thus obtained was adhered onto porous X polypropylene (Duraguard 2400, manufactured by Polyplastics). The film thickness was 0.1 μm or less. Separation coefficient α (o2/PN
2) was 2.2. The remaining membrane t was left in a humidity-resistant tank at a temperature of 60°C and a relative humidity of 96°C, and was removed from the tank every 100 hours to determine the membrane's separation coefficient α (P02/PN2
) was measured, and α was 2.0'i in 1000 hours.
I went down.

Effects of the Invention As described above, since the gas separation membrane of the present invention does not contain trimethylsilyl groups that are easily hydrolyzed, the reliability of its characteristics is improved, and the membrane has great practical effects.

Claims (2)

[Claims] (1) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ A gas separation membrane made of a compound with the above structure (a copolymer of p-vinylphenol and styrene) and a copolymer of polysulfone and polysiloxane. (2) Polysulfone is fluorinated polysulfone▲
The gas separation membrane according to claim (1), which includes mathematical formulas, chemical formulas, tables, etc.