JPS60206403A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To obtain a gas separation membrane having excellent selectivity while holding good gas permeability, by irradiating an 1-monoalkyldimethylsilylpropine polymer membrane with ultraviolet rays. CONSTITUTION:The polymer used in a membrance comprises 1-monoalkyldimethylsilylpropine. The alkyl group contains 1-12 carbon atoms and, concretely, is selected from methyl, ethyl, propyl, iso-butyl, and tertiary-butyl. This polymer is used alone or along with the other polymer to perform the formation of the membrane according to a known method. At this time, the above-mentioned polymer is required in an amount of 50wt% or more. This membrane is irradiated with ultraviolet rays having a wavelength of 40-400nm for about 0.1- 10sec at intensity of 10-1,000mW/cm<2>. Irradiation is applied to the membrane from above at a room temp. in an arbitrary gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas separation membrane. More specifically, the present invention relates to a gas separation membrane having high selectivity.

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

The present inventors previously discovered that 1-monoalkyldimethylsilylpropyne polymers are excellent feeds with excellent gas permeability, but as a result of further studies, it was found that 1-monoalkyldimethylsilylpropyne polymers are mainly The present inventors have discovered that when a gas separation membrane is irradiated with ultraviolet rays, it exhibits excellent selectivity while maintaining good permeability, leading to the present invention.

In other words, the group consisting of the ultraviolet irradiator includes a straight chain alkyl group such as methyl, ethyl, propyl, butyl group, etc.; a branched alkyl group such as isobutyl group. group, tert-butyl group, etc.

Examples of the 1-monoalkyldimethylsilylpropyne used to obtain the polymer having a repeating unit represented by the general formula (1) include 1-trimethylsilylpropyne, 1-monoethyldimethylsilylpropyne, 1-mono-n -propyldimethylsilylpropyne, 1-monolobyldimethylsilylpropyne, and the like. Among these, preferred is 1-trimethylsilylpropyne.

1-Trimethylsilylpropyne is a commercially available monomer (a product of Petrarch in the United States, a product of Chisso's SP Development Department, T172).
8) can be used. As a method for obtaining this polymer, the above-mentioned catalyst is based on group V transition metals such as niobium (Nb) and tantalum (Ta) (for example, NbCl5, Nb
Br3, TaBr3), and in the presence of solvents (aromatic hydrocarbons such as benzene, toluene, xylene, alicyclic hydrocarbons such as cyclohexene, chlorinated solvents such as 1,2-dichloroethane, carbon tetrachloride, etc.) Bottom, usually 3
It can be obtained by polymerizing at 100°C for 12 to 36 hours. It can also be obtained by the method described in Japanese Patent Application No. 58-84626.

The obtained polymer is a white fibrous or powdery polymer. Its number average molecular weight is usually 10,000 by light scattering method.
or more, preferably 100,000 or more.

In the present invention, the 1-monoalkyldimethylsilylpropyne polymer may be used in combination with other polymers, if necessary. Other polymers include 1-alkyne polymers (polymers such as tertiary butylacetylene, neopentylacetylene, ternary pentidolacetylene, etc., preferably tertiary butylacetylene polymers), vinylorganosilane polymers ( Polymers such as vinyltrimethylsilane, vinyltriethylsilane, vinyltripropylsilane, preferably vinyltrimethylsilane polymers), polyorganosiloxanes (dimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, etc.), cellulose polymers (ethylcellulose, etc.) , hydroxyethyl cellulose, triacetyl cellulose, etc., preferably ethyl cellulose), α-olefin polymers (4-methylpentene-1 polymer, etc.), alkyl sulfone polymers (
copolymers of α-olefin and SO□, preferably long-chain alkyl sulfone polymers with alkyl groups having 10 to 20 carbon atoms), tertiary amine-containing polymers (vinylpyridine polymers, N1N-diethylaminoethyl Examples include acrylate polymers, N,N-dimethylaminostyrene polymers, and preferably vinylpyridine polymers.

When the monoalkyldimethylsilylpropyne polymer and the second component (another polymer) are used together, the content of the monoalkyldimethylsilylpropyne polymer is usually 50% by weight or more, preferably 70% by weight or more.

In the present invention, the method for producing a gas separation membrane mainly formed from monoalkyldimethylsilicate and lupropine polymers is as follows: (1) A composite membrane is produced by coating a porous substrate with a solution in which the above polymer is dissolved in a solvent. Method, (2
) After dissolving the above polymer in a solvent and applying it on a porous substrate,
(3) The polymer is dissolved in a solvent and then spread on the water surface to form a so-called water surface thin film. One method is to layer it on a porous substrate to form a composite membrane. Regarding these specific methods, see Japanese Patent Application No. 58-186222, Japanese Patent Application No. 58-186834, Japanese Patent Application No. 1987-2005~'59, Japanese Patent Application No. 1987-24.
It is described in each specification of No. 2775.

The ultraviolet light used to obtain the ultraviolet irradiator of the gas separation membrane, which is a feature of the present invention, has a wavelength of 40 nm to 400 nm.
Any UV light can be used.

Specifically, UV curing equipment for photosensitive resins (for example, Ushio Electric UV-2 (!, 01), light sources for photochemical reaction devices (for example, Eikosha, high pressure mercury lamp, and low pressure mercury lamp),
A UV lamp for spot detection in thin layer chromatography, natural light (sunlight), etc. can be used.

As for the intensity of the irradiation, irradiation with an arbitrary intensity of 1 mW/ari" or higher can be used, but the irradiation intensity is preferably 10 to 1000 mWA-If.

The irradiation time varies depending on the irradiation intensity, but for example, 50 to 200
When mW/cm2 is used, it is desirable that the time be within 10 seconds rather than 0.1 seconds.

The irradiation is usually carried out from above the gas separation membrane, and can be carried out at room temperature and in air or any gas.

Note that the 1-monoalkyldimethylsilylpropyne polymer can also be subjected to surface treatments such as ultraviolet ray irradiation (gamma rays, neutron beams, electron beams) irradiation, corona discharge treatment, and the like.

The gas separation membrane of the present invention is mainly formed from a 1-monoalkyldimethylsilylpropyne polymer, and has improved gas permeation selectivity while maintaining good gas permeability.

Since it has the above effects, it can be applied to various gas separation membranes. Application examples include oxygen enrichment membranes (combustion, medical), aqueous separation membranes (H2/CO separation, H2 recovery from ammonia synthesis purge gas), CH4/CO
2 separation membranes (for methane fermentation, tertiary oil recovery) and
It can be used in a wide range of applications, including artificial lungs, artificial carp materials, and membranes for air electrodes.

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

Example 1 1-trimethylsilylpropyne polymer (hereinafter referred to as PMSP)
The intrinsic viscosity of PMS P is 6.9 in toluene at 30° C.) was dissolved in toluene (1% weight concentration). The solution was cast onto a glass plate and cast to form a thick film. After drying under reduced pressure at 80° C. for 10 hours, the thickness of the film was measured to be 40 μm. Thereafter, ultraviolet rays were irradiated for 3 seconds using a UV curing device (Unicure System UV-2001, manufactured by Ushio Inc.). The irradiation intensity was 170 mWA-IrL2.

Thereafter, the permeability coefficients of oxygen and nitrogen were measured for the unirradiated film and the irradiated film using a gas permeation evaluation device manufactured by Rika Seiki Kogyo (manufactured by Rika Seiki Kogyo Co., Ltd.). The results are shown in Table 1.

Table 1 Example 2 PMSP and polyvinyltrimethylsilane (hereinafter referred to as PVMS)
) was dissolved in toluene at a weight ratio of 0.8:0.2. A thick film (thickness 81 mm) was prepared in the same manner as in Example 1.
μ) was obtained, and ultraviolet rays were also irradiated under the same conditions. Gas permeability (
Table 2 shows the evaluation results of permeability coefficient and separation coefficient.

Table 2 Example 3 ' PMSP used in Example 1p was added to tetrahydrofuran at 1%.
Dissolved by weight. The solution was cast onto a glass plate using an 850μ applicator, a portion of the solvent was evaporated for 10 seconds at room temperature, and the solution was poured into ice water to solidify. Furthermore, after completely removing the solvent by immersing it in running water day and night, it was air-dried to prepare a dry asymmetric membrane. Thereafter, UV was irradiated for 0.5 seconds using the same W device as in Example 1. Table 3 shows the results of evaluating the body permeability.

[ - " [ Example 4 P'MSP was dissolved in n-hexane at a concentration of 1.5% by weight. Furthermore, an activator of sorbitan oleate monoester having an HLB of 4.8 was added to the solution in an amount of 5% by weight of O, OO. % of the solution. 0.4 g of the solution was added to a side of 3
A thin polymer film was formed when gently added onto the water surface (tap water was used) in a 0 CTL square stainless steel water bath (15'C). The average film thickness was calculated from the film area of the obtained ultra-thin film to be about 0.01 μm. This thin film was used as a porous layer support layer.
- A composite membrane was prepared using a semipermeable membrane of phenyl-2-chloroacetylene polymer (Japanese Patent Publication No. 84164/1983). Irradiation was carried out in the same manner as in Example 1. The irradiation time was 0.2 seconds. The results of evaluating gas permeability are shown in Figure 4.

Claims (1)

[Claims] 1. A ~1-selective gas separation membrane comprising an ultraviolet irradiated body of a 1-monoalkyldimethylsilylpropyne polymer membrane. 4. The membrane according to claim 1, wherein the 21-monoalkyldimethylsilylpropyne polymer is a polymer having repeating units of the general formula. 3. The ultraviolet irradiator has an ultraviolet intensity of 10 to 10100O/7
Claim 1, which is irradiated with
Membrane described in section.