JPS6012103A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To provide a separation membrane keeping excellent gas permeability and having further improved separation property, constituted by combining an alkyl group substituted acetylene polymer having a specific formula with an 1- monoalkyldimethylsilylpropine polymer. CONSTITUTION:A gas separation membrane consists of an 1-monoalkyldimethylsilylpropine polymer A having a repeating unit represented by formula I (wherein R1 is 1-12C straight chain or branched chain alkyl) and an alkyl group substituted acetylene polymer B having a repeating unit represented by formula II(wherein R2 is 4-10C branched chain alkyl). The O2-permeability of this separation membrane is usually about 10<-9>-10<-7>cc.cm/cm<2>.sec.cmHg and the coefficient of separation of O2 and N2 thereof is usually within a range of 2.0- 5.0.

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 good gas permeability and selective permeability.

BACKGROUND ART In recent years, a method using a monopolymer thin film as a means for separating and concentrating a specific gas (oxygen, nitrogen, etc.) from a mixed gas (air, etc.) has been attracting attention.

Although the inventors have previously discovered that 1-monoalkyldimethylsilylpropyne polymers are excellent materials with excellent gas permeability, they retain body permeability and provide improved separation. The present invention was achieved by discovering that a gas separation membrane having the following properties can be obtained. That is, the present invention provides 1 having a repeating unit represented by the general formula (wherein R1 is a linear or branched alkyl group having 1 to 12 carbon atoms)
- Monoalkyldimethylsilylpropyne polymer (A) and an alkyl group-substituted acetylene polymer having a repeating unit represented by the general formula (in the formula, good is a branched alkyl group having 4 to 10 carbon atoms) This is a gas separation membrane formed from the combination (B).

In the general formula (1), the straight chain alkyl group of turtle CX-12 is a branched alkyl group such as methyl, ethyl, propyl, butyl, pentylhexyl,
Heptyl, octyl, nonyl, tesyl.

Dodecyl group and the like; branched alkyl groups such as isobutyl group and tertiary-butyl group.

Examples of 1-monoalkyldimethylsilylpropyne used to obtain a polymer having a unit represented by general formula (1) as a repeating unit include 1-trimethylsilylpropyne, 1-mono-lopropyldimethylsilylpropyne, 1-mono-lopropyldimethylsilylpropyne,
Examples include -mono-0-hexyldimethylsilylglobin, 1-mono-rhodecyldimethylsilylprobin, and mixtures of two or more thereof. Among these, preferred is 1-trimethylsilylpropyne.

l-Trimethylsilyl [≠ Tomipropyne is a commercially available monomer (product of Betrak in the United States, product T of SP Development Department of Chisso Corporation)
8728) can be used.

This polymer is made by combining the above monomer with niobium (
Nb)s Tantalum (Ta) based catalysts (e.g. 'N
bC)5, TaCnos + NbBr5, Ta
It can be obtained by polymerization in the presence of a monogenide such as Br3. The manufacturing method is based on the patent application No. 58-29786.
It is stated in the specification of the No.

In addition, this polymer uses the above-mentioned monomers as main polymerization catalysts, and uses the above-mentioned catalysts based on niobium (Nb) and tantalum (Ta) as cocatalysts, and organoaluminum compounds (trialkyl aluminum, mono- or di- or mono-alkyl aluminum, etc.). 1-monoalkyl (alkyl group is C
+-+2J dimethylsilylpropyne polymer is usually a white solid with a high molecular weight and an intrinsic viscosity of usually 0.5.
(d]/9) or more. Polymers are aromatic hydrocarbons (
benzene-toluene, xylene, etc.): halogenated hydrocarbons (carbon tetrachloride, chloroform, etc.); soluble in alicyclic hydrocarbons (cyclohexane, etc.) and mixtures of two or more of these. , branched alkyl groups having 4 to 10 carbon atoms on the island include tertiary-butyl group, 2-methylpropyl group, 8-methylpropyl group, 2-methylbutyl group, tertiary-pentyl group, neopentyl group, 2-methylpropyl group,
Examples include methylpentyl group, 8-methipentyl group, 4-methylpentyl group, and 2-ethylhexyl group.

Specific examples of the alkyl group-substituted acetylene having the unit represented by general formula (2) (1-alkyne unit) as a repeating unit include tertiary-butylacetylene, 4-methyl-1-pentyne, 3-methyl-1-pentyne , neopentylacetylene, tertiary-pentylacetylene,
Examples include tertiary hexylacetylene, 1-hexyne, and mixtures of two or more of these. Among these, tertiary-butylacetylene is preferred.

The method of obtaining the alkyl group-substituted acetylene polymer (B) is the method of Higashimura, Masuda et al. (Polymer:),
Vol 14°No, 6, pp 477-488
(1982), Polymer Bull, 2
, 828 (1980)], specifically, using an alkyl-substituted acetylene monomer having a 1-alkyne unit with a Mo- and/or W-based catalyst ('Mo
C) 5゜WC Karasu, combination of MoCJLs and WCi6] and solvents (hydrocarbon solvents such as toluene and cyclohexane; oxygen-containing organic solvents such as Koichiro and ketones; chlorine-based organic solvents such as carbon tetrachloride; A method of polymerizing in the presence of a mixed solvent of two or more types, usually at 0 to 40°C for 12 to 36 hours, and a method of polymerizing a metal carbonyl (M
There is a method of polymerizing by irradiating ultraviolet rays in carbon tetrachloride using o (CO) a , W (Co ) a ).

Regarding the polymerization method, see Japanese Patent Application No. 57-105089 and No. 57.
-105040, 57-107848 and 5
No. 7-15411.

The obtained alkyl group-substituted acetylene polymer (B) is usually a nearly white solid, and its number average molecular weight is usually 20,000 or more, preferably 100,000 to 5,000,000, particularly preferably 200,000 to 100,000 by osmotic pressure method. Ten thousand.

Alkyl group-substituted acetylene polymer (B) in the present invention
is an aliphatic, aromatic or alicyclic hydrocarbon (n-hexane, benzene, xylene, cyclohexane, etc.), hero,
Soluble in hydrogenated hydrocarbons (carbon tetrachloride, trichlorethylene, etc.) and two or more of these.

The membrane of the present invention is formed from polymer (4) and polymer (B). The weight ratio of (N and fB) can be varied over a wide range, for example, from 10/90 to 90/10, but if you want to obtain a highly permeable separation membrane, use a polymer (with a large amount of N) and vice versa. When it is desired to obtain a membrane with high separation properties, it is preferable to use a large amount of polymer (B).

Methods for obtaining a gas separation membrane formed from a polymer (and polymer (B)) include (1) forming a membrane from a solution mixture of two components by a known method; (2) a known method for each component in advance; (3) A method in which one component is formed into a film by a known method and other components are formed into a film to form a composite.

Method (1) is (using N and (B) in a common solvent, such as an aromatic hydrocarbon solvent such as benzene, toluene, or xylene, or an alicyclic hydrocarbon solvent such as cyclohexane).
A known method of obtaining a membrane from a solution mixture by dissolving it in a chlorinated solvent such as carbon tetrachloride or chloroform (Japanese Unexamined Patent Application Publication No. 1983-1999)
166901, etc.) Specifically, a polymer solution can be cast onto a solid with a smooth surface (e.g. glass, metal) or a liquid plane (e.g. water surface) and the solvent can be evaporated to form a film. The method of obtaining an ultra-thin film by dropping the polymer solution onto the liquid surface, especially the water surface, and allowing the polymer solution to spread spontaneously on the water surface, has good film spreadability and a large area with few poles or extremely weak parts. It becomes easy to obtain an M film. In addition, it can also be obtained by known molding methods for thermoplastic resins (such as extrusion molding). In the method (2), the bonding method includes a pressure bonding method. When press-bonding, if a thin layer of common solvent for both components is applied, the films of the two components will stick together and will not easily peel off.

(3) A method of forming a film of one component onto a film of one component formed by a known method to form a composite is to apply a polymer solution of the other component onto the film of one component. A method of high-frequency sputtering of the other component onto the film of the 1 component, and a method of using the film of one component as a base material for the water surface film of the other component.

The membrane of the present invention may be composed of the polymer (5) and the polymer (B) represented by the general formula (1), but it may also be one obtained by processing another eighth component. For example, increase the gas separation by an additional 6ff.
A vinyltriorganosilane polymer may be further added to the polymer (5) and the polymer (the two components of the odor) in order to improve the ratio of oxygen and nitrogen permeability coefficients. is particularly high 1
Suitable for this purpose = 10010 to 10/90. As the amount of vinyltriorganosilane increases, the gas permeability tends to decrease slightly, but the gas separation properties tend to improve. The weight ratio of (A) and [: (B) + (Q)] is usually 10/90 to 90/10.Other polyorganosiloxanes (dimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane and their derivatives) or various olefinic polymers such as 4-methylpentene may be added.As a method of adding, a method of coating the film of the present invention with the above-mentioned other third component (for example, JP-A-57 -4208) and polymer (A) and polymer (I3
) is further mixed with another third component to form a film. These vinyl triorganosilas may also contain additives as necessary to improve the spreadability of the ultra-thin film.
Various additives (for example, plasticizers) may be added.

The membrane of the present invention may be in any form such as a flat membrane, a tubular membrane, or a hollow fiber.

The film thickness of the membrane of the present invention is usually 0.01 to iooμ in order to have a sufficient amount of gas permeation (having practical strength),
Preferably it is 0.05-20μ.

The membrane of the present invention can also be composited with a support, if necessary. Extraction method and paper making method are used as supports.

Porous supports made by various methods such as phase separation method and stretching method [for example, Japanese paper, F paper 9 synthetic paper.

Filtration membrane, ultrafiltration membrane, plastic porous M (polypropylene porous membrane, etc.)] 2-knit woven support (cloth, etc.),
Examples include non-woven supports (such as non-woven fabrics), wire mesh, and the like. The compositing method may be a well-known method, for example, by attaching a film formed on the water surface to a support under pressure, scooping it up, or adhering it to the support by suction. can. An adhesive or the like may be present between these supports and the membrane for support. Furthermore, the membrane supported on the support may be heat-treated.

The gas separation membrane of the present invention usually has an oxygen permeability coefficient of 10-9 to
The separation coefficient between oxygen and nitrogen is usually in the range of 2.0 to 5.0.

The membrane of the present invention has a gas permeability 9 separation factor and thinning properties (
Both have excellent workability. That is, polydimethyl 7-loxane also has an excellent separation coefficient between oxygen and nitrogen, and also has excellent thin film forming properties. It also has a better permeability coefficient than olefin polymers.

Since the membrane of the present invention exhibits the above-mentioned effects, it can be incorporated into a device for producing oxygen-enriched air from air and used to improve the combustion efficiency of engines, boilers, heating appliances, etc. Also, in the field of turbocharger shear replacements that increase engine combustion efficiency, heating furnaces and firing furnaces that reach high temperatures of over 11,000 degrees Celsius? It is expected to save 80 to 50 inches of energy when used in glass melting furnaces. In addition, as clean oxygen-enriched air) nursery boxes for premature infants.

Artificial lung as a treatment device for patients with respiratory diseases.

Can be used as artificial gills and contact lenses.

Examples of oxygen-enriched combustion devices incorporating the membrane of the present invention include Nikkei Plastics Co., Ltd., Koto, October 1981;
Examples include the oxygen-enriched combustion system described on page 8. The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Production Example 1 (1) Polymer (A) Trimethylsilylpropyne was added to 100ml of toluene at 0.00ml.
1 mo! 1 mmoi of TaCJe was added as a catalyst, and polymerization was carried out at 80° C. for one day. The generated polymer gel was similarly diluted and precipitated to obtain a polymer (N. (molecular weight: 1,100,000). (2) Polymer (B) Tertiary-butylacetylene was added to 100 m of toluene in an amount of 0.1 molar. A viscous polymer gel was produced by adding im mono using Mo C sulfur as a catalyst and carrying out polymerization at 80° C. overnight in the dark.

This polymer gel was diluted and dissolved in toluene, and purified by extraction into a large amount of methanol. This polymer was designated as Polymer (B). (Molecular weight: 230,000) Examples 1 to 6 A toluene solution of polymer (5) and polymer (B) alone and at the mixing ratio (based on weight) listed in Table 1 was prepared.◎Polymer in solution The concentration was 2%.

Separation membranes were created by casting a toluene solution of each polymer onto a glass plate. Next, the gas permeability (gas permeability coefficient) of oxygen and nitrogen of each membrane was measured at 25° C. using a gas permeability measuring device manufactured by Rika Seiki Kogyo, and the separation coefficient was determined. The results are shown in Table-1.

Table 1 Examples 7 to 10 A single film of (B) having a film thickness of lOμ was prepared in the same manner as in Examples 1 to 6. Next, individual films (8) having different film thicknesses were created. The film thicknesses were 10, 20, 80, and 40μ.

Apply a thin layer of toluene to the surface of each film in (8), stack the film in (B) with a thickness of 10μ, and press it once), then reduce the pressure.
It was dried at 80° C. for 5 hours to create a composite membrane. The gas permeability coefficient and separation coefficient of oxygen and nitrogen of the obtained composite membrane were evaluated in the same manner as in Examples 1 to 6. The results are shown in Table 2. Table-2

Claims (1)

[Claims] l- having a repeating unit represented by 1 (in the formula, ``bird'' is a linear or branched alkyl group having 1 to 12 carbon atoms)
An alkyl group-substituted acetylene polymer (
A gas separation membrane formed from uniform. 2. The separation membrane according to claim 1, in which (N is a trimethylsilylpropyne polymer). 3. The separation membrane according to claim 1 or 2, in which (B) is polytertiary-butylacetylene. 0