JPS58223407A - Gas separation film - Google Patents

Abstract

PURPOSE:To form a gas separation film superior in permeability, separation performance, and physical film property, by using an alkylated acetylene polymer having 1-alkyne units and a specified structural formula for said resin. CONSTITUTION:An alkylated acetylene polymer having 1-alkyne units obtained from 4-methyl-1-pentyne, 3-methyl-1-pentyne, tertiary pentyl acetylene, neopentyl acetylene, or the like acetylen type monomer is dissolved in a solvent, such as n-hexane, benzene, xylene, carbon tetrachloride, trichloroethylene, and cast into a 0.01-100mum thick film. The obtained gas permeation film has permeability comparable with that of polydimethylsiloxane, it is distinguished in separation performance of O2 from N2, and it can be formed easily into a thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas separation membrane. More specifically, the present invention relates to a selective gas permeable membrane having good gas permeability and selective permeability (separability).

In recent years, methods using polymer membranes have been attracting attention as a means of separating and concentrating specific gases (oxygen, gas, etc.) from mixed gases (air, etc.). For example, polydimethylsiloxane is used as a material for polymer membranes.

Polydimethylsiloxane-polycarpo-block copolymer (U.S. Pat. No. 8,980,456, No. 8,874,986)
No.), polydimethylsiloxane copolymer (Japanese Patent Application Laid-open No. 1983-
No. 26504, etc.) and olefinic polymers such as poly(4-methylpentene-1) (JP-A No. 57-42)
No. 03) is known. However, these are gas permeable [
Permeability coefficient of specific gas (e.g. oxygen) (Po□)]22
Separability Permeability coefficient ratio (separation coefficient) (PO2/PH1)
) and film properties were not all satisfied.

The inventors of the present invention have arrived at the present invention as a result of intensive studies aimed at obtaining a gas separation membrane with excellent gas permeability, separation properties, membrane physical properties, and processability for forming a thin film. That is, the present invention provides a gas separation membrane formed from an alkyl group-substituted acetylene polymer having a 1-alkyne unit represented by the general formula (in the formula, ■ represents a branched alkyl group having 5 to 20 carbon atoms). be.

branched alkyl groups such as neopentyl, tertiary-pentyl, tertiary-hexyl and branched alkyl groups having no quaternary carbon atoms, such as 2-methylbutyl, 2-methylpentyl, 3-methylpentyl;

4-methylpentyl group. Examples include 2-ethylhexyl group. Preferred among R1 are branched alkyl groups having a quaternary carbon atom, and particularly preferred are tertiary pentyl and neopentyl groups.

The carbon number of 几 is 5 to 20, preferably 5 to 9.

If the number of carbon atoms is 4 or less, the permeability will be poor when formed into a membrane. Further, in the case of a straight alkyl group, the permeability also decreases.

Examples of acetylene monomers used to obtain the polymer having a 1-alkyne unit represented by the general formula (1) include 4-methyl-1-pentyle, 3-methyl-1-pentyne, tertiary-pentylacetylene, neopentylacetylene, and the like. There are two or more types. Among these, preferred are tertiary pentylacetylene and neopentylacetylene.

The polymer in the present invention has the general formula (represented by 1) 1
-Although it may be one obtained by polymerizing an acetylene monomer that provides an alkyne unit, it may also be one obtained by copolymerizing this acetylene monomer with another 1-alkyne if necessary. Such other 1-alkynes include the general formula (wherein R2 is a linear alkyl group having 1 to 20 carbon atoms,
Alternatively, it represents a branched alkyl group having 1 to 4 carbon atoms. ) Acetylene monomers that provide a 1-alkyne unit can be mentioned.

Examples include octyl group, decyl group, dodecyl group, 'hexadecyl group, and ru group. Examples of the branched alkyl group having 1 to 4 carbon atoms include tertiary-butyl group, 2-methylpropyl group, 3-methylpropyl group, and 2-methylbutyl group.

Examples of acetylenic monomers that provide the 1-T alkyne unit represented by the general formula (2) include 3,3-dimethyl-1-butyne (cushary-butylacetylene), 1-nopentyne, 1-hexyne, 1-octyne, etc. More than one species can be mentioned.

In addition, the polymerization product in the present invention may be a copolymer of an arylacetylene monomer if necessary in addition to the 1-alkyne of general formula (1) and (2) if necessary.

As the arylacetylene monomer, phenylacetylenes, halophenylacetylenes, cyanophenylacetylenes, phenylacetylene, and 2-chloro-1-phenylacetylene are preferred. Details of the arylacetylene monomer are described in Japanese Patent Application No. 56-138951 and No. 55-181090.

When copolymerizing 1-alkyne of general formula (1) with 1-alkyne of general formula (2) and/or arylacetylene monomer, the content of 1-alkyne of general formula (1) in all monomers is usually 20% by weight or more, preferably 50% by weight
% by weight or more. If the 1-alkyne of general formula (1) is less than % by weight, the permeability will be poor. In the case of a copolymer, it may be either a block copolymer or a random copolymer.
Higashimura, Masuda et al.'s method (T, Masuda, e
taJ.

Polym, J., 11, 818 (197
9) and Polym, J.

18, 801 (1981)). Specifically, acetylenic monomers were used based on MO and W (catalyst (M, oC15, wc16. M, oCJ5-1'h
4an, WCl6-Ph, 8n, etc.),
Also, solvents (aromatic hydrocarbons such as toluene; ether,
When MoC4 is used, it can be obtained by polymerizing in the presence of oxygen-containing organic solvents such as esters and ketones for 12 to 86 hours, usually at θ to 40°C. ) is also effective.

Furthermore, NbCl5 and TaCJ5 are also effective (Polymer Science Society of Japan).

Proceedings of the 1957 Annual Meeting 11)-28).

In addition to the method for obtaining the alkyl group-substituted acetylene polymer described above, it can also be obtained by a conventional method in which acetylene monomers are polymerized using hydrogen chloride or the like.

Examples of the alkyl group-substituted acetylene polymer having a 1-alkyne unit represented by the general formula (1) that can be obtained include tertiary-pentylacetylene polymer, neopentylacetylene polymer, copolymer of tertiary-pentylacetylene and 1-peatine, etc. can be given.

The polymer in the present invention is usually a nearly white solid,
Its number average molecular weight is usually 20,000 or more, preferably 50,000 to 5,000,000, particularly 100,000 to 1,000,000, as determined by the osmotic pressure method.

Polymers are aliphatic, aromatic or cycloaliphatic hydrocarbons.

(n-hexane, benzene, xylene, cyclohexene, etc.), halogenated hydrocarbons (carbon tetrachloride.

A monopolymer solution can be prepared by dissolving it in a solution such as trichlorethylene, etc., and a film can be made by casting this solution.

The membrane of the present invention is made of the above polymer. What is the film thickness?

In order to have practical strength and obtain a partial amount of gas permeation, the thickness is usually 0.01 to 100μ, preferably 0.05μ to
It is 20μ.

The membrane of the present invention can be produced by a known method (Japanese Unexamined Patent Publication No. 166903/1983). Specifically, a film can be obtained by casting a solution of the polymer onto a solid (eg, glass, metal) or liquid surface (eg, water surface) with a smooth surface and evaporating the solvent. the polymer solution at the liquid level,
In particular, the method of obtaining an ultra-thin film by dropping a polymer solution onto the water surface and allowing it to spread spontaneously on the water surface has good film spreadability and can yield a large-area separation membrane with few pinholes or extremely weak parts. It becomes easier. In addition, it can also be obtained by known molding methods (such as extrusion molding) for thermoplastic resins.

The membrane of the present invention may be made of the polymer represented by general formula (1), but may also be made by processing other second components.

For example, to further increase gas permeability, polyorganosiloxanes with poor film-forming ability (dimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane and their derivatives, etc.) can be added, and various types such as 4-methylpentene can be added. Olefinic polymers may also be added. Methods of adding the other @2 components include a method of coating the membrane of the present invention with the above-mentioned other @2 components (for example, JP-A No. 57-4203), and a method of adding a polymer having a 1-alkyne unit represented by the general formula (1) with other components. The method of creating a film by mixing two components has failed. The amount of the polymer in the present invention when used in combination with the second component is usually at least 20% by weight, preferably at least 50 double stars, in the film.

The membrane of the present invention may also contain various additives (eg, plasticizers) as necessary to improve the spreadability of the polar membrane.

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

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 1 synthetic paper].

Filtration membrane, ultrafiltration membrane, plastic porous gland (polypropylene porous membrane, etc.) 1 Knitted fiber material support (cloth, etc.)
, non-woven fabric supports (such as non-woven fabrics), wire mesh, etc. The compositing method may be a known method, and for example, a membrane formed on the water surface may be brought into close contact with the support by pressure, scooped up, or suctioned through the support to be made into a composite with the support. 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 1. OX
10 cc・an/cm・sec, cs H
g, and the separation coefficient between oxygen and nitrogen is usually 2.5~
It is in the range of 5.0. Elongation is usually 10% or more, preferably 10-10 (1). Tensile strength is usually 100k.
g/cl, preferably 800 kg/C skin or more.

The membrane of the present invention has excellent gas permeability, separation property W, and membrane physical properties. That is, it has a permeability comparable to that of polydimethylsiloxane, superior oxygen and nitrogen separation properties compared to polydimethylsiloxane, is equivalent to or better than olefin polymers, and can be easily formed into a thin film.

Furthermore, the separation membrane of the present invention is superior to a gas separation membrane formed from a polymer having 1-alkyne units represented by general formula (2) but not 1-alkyne units represented by general formula (1). Excellent transparency.

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, and the like. It is also expected to save energy by 80 to 50% when used as a replacement for turbocharger shear to increase engine combustion efficiency, and in heating furnaces, firing furnaces, and glass melting furnaces that reach temperatures of 1000°C or more. Furthermore, as a shield of clean oxygen-enriched air, it can be used as a nursery box for premature babies, a treatment device for patients with respiratory diseases, an artificial lung, two artificial gills, and contact lenses.

2 Examples of oxygen electrification combustion equipment incorporating the membrane of the present invention are listed in Nikkei Plastics, October 1981 issue, 8.
An example of this is the oxygen-enriched combustion system described on page 1.

The present invention will be further explained below with reference to Examples.

The present invention is not limited to this.

Examples 1-5. Comparative Example 1 Various acetylene monomers shown in Table 1 were
Add Q to 00tttt at a ratio of 1 mol, MoC
1r, ・Add Hnmol of Ph% as a catalyst and heat at 30°
When polymerization was carried out overnight at C, a viscous polymer gel was produced. This polymer gel was diluted and dissolved in toluene, and purified by precipitation in a large amount of methanol. After drying, the polymer was redissolved in toluene and cast onto a glass plate to create a permeable membrane.

Next, the gas permeability (gas permeability coefficient) of each layer was measured at 2gC 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

Claims (1)

[Scope of Claims] 1. Formed from an alkyl group-substituted acetylene polymer having a 1-alkyne unit represented by the general formula (wherein R1 represents a divided alkyl group having 5 to 20 carbon atoms) Gas separation membrane. 2. The separation membrane according to claim 1, wherein the alkyl group is a branched alkyl group having a quaternary carbon atom. 3. The separation membrane according to claim 2, wherein the branched alkyl group having a quaternary carbon atom is a tertiary pentyl group or a neopentyl group. 4. The separation membrane according to any one of claims 1 to 8, wherein the separation membrane has a thickness of 0.01 to 100μ.