JPS62176518A - Oxygen enriched membrane - Google Patents

Abstract

PURPOSE:To easily prepare an oxygen enriched membrane carrying superb oxygen permeability coefficient and separation coefficient by utilizing a copolymer comprising more than two kinds of fumarate diester including dialkylfumarate as main component. CONSTITUTION:Dialkylfumarate, particularly dial tertiary butyl fumarate as essential component shown by Formula I, copolymerized with di (fluoroalkyl) fumarate, fumarate organosilane and the like shown by Formula II. By said process, material carrying superb oxygen permeability coefficient and oxygen/ nitrogen separation coefficient is prepared. Dialkylfumarate component should be 50-94mol%. Radical polymerization method is applied. The copolymer thus prepared is dissolved into diethyl ether, chloroform, benzene and the like, and said solution is used for preparing membrane.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an oxygen-enriching membrane, and more specifically, it is easy to produce a thin film, has mechanical strength as a thin film, has a large oxygen permeability coefficient, and is particularly suitable for air The present invention relates to an oxygen-enriching membrane for obtaining air with a high oxygen concentration using the membrane.

[Conventional technology]

BACKGROUND ART Conventionally, industrial techniques for separating oxygen gas from air include a cryogenic separation method that utilizes the difference in boiling points of liquid air components, and a suction/underwear method that utilizes the gas selective adsorption properties of zeolite and the like. Although these separation methods are successful in producing large quantities of highly concentrated oxygen gas, they also have the disadvantage of high equipment and operating costs. In response, membrane separation methods that can separate and concentrate oxygen gas with a small amount of energy have recently been attracting attention.

The membrane separation method uses an oxygen-enriched membrane (
An oxygen enrichment module is constructed using a polymer membrane (polymer membrane), and raw material air is supplied at high pressure or normal pressure into one space partitioned by this oxygen enrichment membrane, and the other space is at normal pressure or reduced pressure. It produces air with high oxygen concentration through the membrane.

As an oxygen-enriching membrane, for example, a porous polymer membrane (Japanese Patent Laid-Open No. 55
-8803), fluorine-containing silicone rubber - porous polytetrafluoroethylene (JP-A-56-5121)
), cross-linked polyorganosiloxane-linear polyorganosiloxane copolymer (JP-A-56-26508), cellulose monocarboxylic acid ester (JP-A-56-265)
No. 26), styrene siloxane polymer α, ω-2 functional polysiloxane crosslinked polymer (JP-A-56-58604
No.), poly(4-methylpentene-1) (JP-A-57
Various proposals have been made, such as poly(tertiary-butylacetylene) (Japanese Patent Application Laid-Open No. 59-42004).

However, the oxygen permeability coefficient (hereinafter referred to as Dk).

), separation coefficient PO□/PNz (hereinafter referred to as α),
There has been no material that satisfies all of the requirements, such as processability for thinning the film and low cost.

Furthermore, Polymer Proceedings, Vol. 34, No. 3, p. 420 (19
85) reports that poly-di-tert-butyl fumarate has four times the Dk and almost the same α value as poly-4-methylpentene-1; This polymer is very hard and brittle, making it difficult to form into a FIV membrane, and it also has the drawback that in order to obtain high oxygen permeability, the high molecular weight polymer in particular must be fractionated and purified.

[Problem that the invention seeks to solve]

Therefore, the inventor of the present invention has conducted extensive research in order to create an oxygen-enriched membrane that can solve the above-mentioned problems, and has found that when a certain kind of fumaric acid diester is used, excellent Dk and α can be obtained. Moreover, they discovered that it has mechanical strength that allows it to be made into a thin film, leading to the completion of the present invention.

[Means to solve problems]

That is, the present invention relates to an oxygen-enriching membrane which is a copolymer containing two or more types of fumaric acid diesters as main components, and wherein at least one type of the fumaric acid diesters is dialkyl fumarate.

The main component of the present invention is fumaric acid diester, but since it is extremely difficult to homopolymerize fumaric acid diester other than dialkyl fumarate, dialkyl fumarate is used as an essential ingredient.

The dialkyl fumarates of the present invention include, for example, general formula (I): ([) IIHC-C-0-
R.

R, -0-C-CH (In the formula, R is a C1 to CI3 linear, branched, or cyclic alkyl group.) Specifically, for example, jetyl fumare-1-,
Linear and branched alkyl fumarates such as dipropyl fumarate, dibutyl fumarate, dialkyl fumarate, dioctyl fumarate, and didodecyl fumarate; dicyclohexyl fumarate, di(tert-butylcyclohexyl) fumarate, bis( Examples include alkyl-substituted or non-alkyl-substituted cyclic alkyl fumarates such as trimethylcyclohexyl) fumarate, among which di-tert-butyl fumarate, diisopropyl fumarate, dicyclo Hexyl fumarate, di-tert-amyl fumarate, etc. are preferred because they are easily homopolymerized, and di-tert-butyl fumarate is most preferred.

Furthermore, since the homopolymer of fumaric acid diester containing a large amount of β-hydrogen is generally hard and brittle, linear dialkyl fumarates such as diethyl fumarate, di-n-butyl fumarate, di-n-octyl fumarate, etc. Polymerization improves mechanical strength (brittleness).

Even with the above-mentioned copolymers, materials with excellent Dk and α can be obtained, but in addition, di(fluoroalkyl)
Even better Dk and α can be obtained by copolymerizing fumarate, organosilane-containing fumarate, or the like.

The di(fluoroalkyl) fumarates are, for example, those of the general formula (■): An integer, b is 0 or 1.

) Among them, a is preferably 1 to 6, and specific examples include bis(trifluoroethyl) fumarate, bis(tetrafluoropropyl) fumarate, bis(hexafluoroisopropyl) fumarate, bis(2,2 ，
3, 3, 4, 4, 5, 5-.

6, 6.7.7-F Tecafluoropentyl) fumarate, bis(2-hydroxy-4,4,5,5,6,7
, 7,7-octafluoro-6-trifluoromethylhebutyl) fumarate and the like are preferably used.

Further, as the organosilane-containing fumarate, for example, the general formula (■): (III) I+ HC-C-0-Q-P P-Q -0-C-CI II (wherein, Q is +CH2 juice → CHz C )-I CHz soup H , 2 is 0 or 1, and m is 1 or 3. P is R2Rz X + -Si -0-Si→C1+Tsuji, 5i-Z+Rz
R2Y r or ■ Si Y2 or →O5i (CI+3) 3) s-q (O5il(
(CIl+) z) q or -73, q is an integer from 1 to 3, n is 2 or 3, and X
, , Y, , Z are the same or different, ■ -R, or -〇 -Si Rt, ■ Xz, Yz, Zz are the same or different, -R.

or s or 0 SiY+ ■ I It is.

Z3 is ORz -3i-R:1 j OSi Rz O , r is an integer of 2 to 4, and Rz and Ri are the same or different and are an alkyl group or a phenyl group of 01 to c3. ), but preferably R2 is a methyl group and R3 is an isopropyl group. Specific examples include bis(trimethylsilylpropyl) fumarate, bis(pentamethyldisiloxanylpropyl) fumarate, bis(( trimethylsilyloxy)tetramethyldisiloxanylpropyl) fumarate, bis((trimethylbis(trimethylsilyloxy)cycloxanyl)propyl)fumaray, bis((tetrakis(trimethylsilyloxy)trimethyltrisiloxanyl)propyl)fumarate, bis(tetramethyl Preferably used are triisopropylcyclotetrasiloxanylpropyl) fumarate, bis(tetramethyltriisopropylcyclotetrasilyloxybis(trimethylsilyloxy)silylpropyl)fumarate, and the like.

Among them, bis(trifluoroethyl) fumarate, bis(hexafluoroisopropyl) fumarate, bis((
Trimethylbis(trimethylsilyloxy)cycloxanyl)propyl) fumarate and the like are preferred from the viewpoint of ease of synthesis and purification.

The oxygen-enriched membrane of the present invention contains a total of ff1l of fumaric acid diester.
It is preferable to use 50 to 95 mole parts of the above-mentioned dialkyl fumarate which is easily homopolymerized per 0 mole parts. 5
If it is less than 0 mole part, the degree of polymerization and polymerization rate will decrease, and if it is more than 95 mole part, it will become too brittle. Therefore, 5 to 50 mole parts of other fumaric acid diesters are used.
It is also possible to use copolymerizable monomers other than fumaric acid diester to change elasticity and the like.

In this case, it should be used in an amount of 20 mole parts or less per 100 mole parts of the total fumaric acid diester so as not to lower Dk and α.

Polymerization methods for the above compounds include bulk polymerization, suspension polymerization,
Using conventional radical polymerization methods such as solution polymerization,
It can be carried out at a temperature of -110°C. Among these, bulk polymerization is particularly preferred since the polymerization rate increases. In addition, examples of polymerization initiators that can be used include benzoyl peroxide,
Examples include azobisisobutyronitrile and azobisdimethylvaleronitrile, and these may be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably 0.01 to 1.0 parts by mole based on 1100 parts by mole of the total monomer ff.

The copolymer in the present invention can be dissolved in diethyl ether, chloroform, benzene, etc. to form a polymer solution, and by casting this, an oxygen-enriched membrane can be created. Alternatively, as a polymerization method, a thin film can be obtained by placing a hexamer mixture into a gap of about several to several tens of microns and polymerizing it.

In the present invention, the membrane can be prepared by generally well-known methods. For example, methods include casting a polymer solution onto a solid (eg, glass, metal, etc.) or liquid surface with a smooth surface (eg, a conical surface) and evaporating the solvent. The shape of the membrane may be flat membrane, tubular, hollow fiber, thread, etc., and the present invention can be applied to any of these shapes. It can also be combined with a support if necessary. Porous supports made by various methods such as extraction methods, paper-making methods, phase separation methods, and stretching methods (e.g., Japanese paper, filter paper, synthetic paper, filtration membranes, ultrafiltration membranes, rags, etc.) can be used as supports. Examples include porous plastic membranes such as propylene porous membranes), knitted fabric supports (cloth, etc.), nonwoven fabric supports (nonwoven fabrics, etc.), wire mesh, and the like. The method of compounding may be a known method, such as coating a dilute solution on the support and drying it, pressing a film formed on the water surface onto the support, scooping it up, or passing it through the support. A compositing method can be used, such as compositing with a support by suctioning and adhering to 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.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited only by the examples.

(Example 1) Ditert-butyl fumarate 0.022 mol (5,
0g) and bis(2,2,2-trifluoroethyl)
fumarais) 0.0055 mol (1,54 g) 5011
1 in a glass ampoule, and further added 2.75 x 10-' mol (0,0
067g), then reduce the pressure (10-3maiHg)
The container was sealed and a polymerization reaction was carried out at 72° C. for 17 hours. After the reaction is completed, the reaction mixture obtained is 100%! The polymer was dissolved in chloroform, then poured into a large amount of methanol to form a precipitate, and the precipitate was filtered and dried to obtain a polymer.

0.2 g of the obtained polymer was added to 10 all of diethyl ether.
The solution was dissolved in water and cast onto a 70 mmφ Petri dish to obtain a film with a film rg of 25μ. After the obtained film was peeled off, it was vacuum dried for 48 hours or more, and an air circulation test was performed to measure Dk and α. The results are shown in Table 1 together with the results of other Examples. The conditions for measuring Dk are as follows.

Dk = Gas chromatography detection was performed using the low vacuum method. The measurement temperature was 35°C, the measurement gas pressure was 0.5g/cal,
Unit: ctA 8 sec 0 cml 1 g (Examples 2 to 8) The same procedure as in Example 1 was performed except that the formulation, polymerization initiator, and polymerization conditions were changed. The results are shown in Table 1 together with Example 1 (Example 9). Butyl fumarate 4.39 x 10-' moles (1,0 g), bis(3-(3,3,3-1-dimethyl-1,1-bis((trimethylsilyl)oxy)cycloxanylpropyl) fumarate 3.59 X 10-
mol (2,83 g) and 7.97 X 10-' mol (0,0019 g) of benzoyl peroxide as polymerization initiator
) were mixed and heated to 50°C to dissolve. After the solution was thoroughly degassed in a vacuum line and replaced with nitrogen, the mixed solution was filled into a glass plate (100 a+m square) with a gap of about 50 μm, and polymerized for 24 hours in a dry product at 70° C. After further heating at 100° C. for 3 hours, the temperature was returned to room temperature to obtain a colorless and transparent film. As a result of performing an air permeation test on the obtained membrane, Dk was 1.63X10-' and α was 2.73.

(Example 10) Ditert-butyl fumarate 4.39 x 10-
'mol (1,0 g), bis(3-(3,3,3-trimethyl-1,1-bis((trimethylsilyl)oxy)cycloxanylpropyl) fumarate 2.19X10-'
mol (1,73 g), bis(2,2,2-trifluoroethyl) fumarate 7.31 X 10-' mol (0
, 20g) and benzoyl peroxide 7 as a polymerization initiator.
．． 31 X 10-' moles (0,0018) moles were mixed and heated to 50<0>C to dissolve. After that, the same operation as in Example 9 was carried out, and as a result, Dk was 1.43×10-'' and α was 2.83.

(Comparative Example 1) When only ditertiary-butyl fumarate was used as a monomer and the other operations were carried out in the same manner as in Example 1, the polymer was extremely brittle and could not be formed into a film.

〔Effect of the invention〕

The oxygen-enriching membrane of the present invention has excellent oxygen permeability coefficients and separation coefficients, and is easy to form, so it can be used in various shapes and on various supports.

(Margin below)

Claims (1)

[Claims] (1) An oxygen enrichment membrane which is a copolymer containing two or more types of fumaric acid diesters as main components, wherein at least one type of the fumaric acid diesters is a dialkyl fumarate.