JPS614507A - Separation membrane and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a membrane which is suitably used for the separation or the pervaporization of various kinds of gasses by using polysiloxane compds. contg. amino group or hydroxyl group and polyisocyanate compds. CONSTITUTION:A permselective membrane is obtained by allowing polyaminopolysiloxane having two or more amino groups and at least two siloxy bonds in the molecule or polyhydroxyl polysiloxane having two or more silanol groups to react with polyisoxyanate having at least two isocyanate groups or siloxane series polyisocyanate component under the existence of basic catalyst at 40- 200 deg.C. The film thickness is 30Angstrom -10mum and the permselective membrane is used by keeping it on a porous supporter.

Description

[Detailed Description of the Invention] The present invention provides a separation membrane! Regarding separation membranes having permselectivity for gas mixtures, more specifically, separation membranes suitable for obtaining oxygen-enriched air from air. t″・Currently, devices that utilize combustion energy, such as household Wk
Room appliances, automobiles/engines, boilers, etc. are designed and used on the basis that oxygen exists in the air at a concentration of 20%. However, if air with increased oxygen concentration is supplied, not only will problems such as environmental pollution caused by incomplete combustion be solved, but it will also be possible to increase combustion efficiency.

Air with increased oxygen concentration is also useful as breathing air for people with respiratory diseases and premature infants.

For this purpose, various separation membranes having selective gas permeability for obtaining air with increased oxygen concentration from air have been developed. This separation membrane is required to have the ability to separate oxygen and nitrogen from the air and allow the oxygen to permeate through the membrane at a sufficiently high rate. Silicone rubber, which was first used as a membrane material to separate oxygen and nitrogen in the air, has a separation coefficient (α) of 2.0 and an oxygen permeability coefficient of 6 x 1.
0-8cc (STp)-cIL/al-sec
・It has the performance feature of crtH9. This material has a high permeability coefficient but a low separation coefficient, and therefore materials with high permeability and separation coefficients have been developed.

Incidentally, the amount of gas permeating through a homogeneous membrane is expressed by the following formula 2, %. Therefore, if a material with a high separation coefficient (α) can be found, even if the permeability coefficient (P) is small, the permeation rate can be increased by making the film thickness (7) as thin as possible. One method has been developed and put into practical use, in which a monomolecular film of an organic polymer is spread on the water surface to form an ultra-thin film, and this is supported with a porous support to form a gas separation membrane. (% Kaisho 57-
71605, JP-A-51-89564).

However, this method: ■ The membrane formed is limited to a flat membrane; ■ Since the membrane is extremely thin, there is a limit to improving its mechanical strength. ■ There are limitations in terms of materials to make it a practical separation membrane. It has some disadvantages, such as:

On the other hand, a thin film of a reactive compound solution is formed on the support, and a solution containing a compound that reacts with the compound and capable of forming an interface with the solution is brought into contact with the thin film of the solution to cause an interfacial reaction on the support. There is a method of forming an extremely thin film on a support. This method is advantageous as a film forming method in that it hardly has the above-mentioned drawbacks of the water surface spreading method.

The present applicant focused on the characteristics of the silicone rubber, modified it materially, turned it into a solution as polyamino silaxane, and applied the above-mentioned interfacial reaction to it using polyisocyanate, thereby achieving excellent separation. The membrane has already been proposed (Japanese Unexamined Patent Publication No. 193703/1983). However, the inventor of the present invention aimed to obtain a separation membrane having even higher performance than such a separation membrane (after further research, it was found that instead of the above-mentioned polyamino silaxane component, a polyoxyaxane containing both amide 7 groups and silanol groups was used). The present invention was completed based on the discovery that a separation membrane with a higher permeability coefficient and a higher separation coefficient could be obtained by using these components.

That is, the present invention provides a selectively permeable membrane (Bl) formed from a support (4) and a polysiloxane compound component and a polyisocyanate compound component present thereon, in which the polysiloxane compound component is The present invention relates to a separation membrane containing a hydroxyl group and a hydroxyl group, and a method for producing the same.

The support in the present invention is not particularly limited as long as it has gas permeability and supports and strengthens the selectively permeable membrane FB+, but is generally an organic or inorganic porous material. is used.

As a base material for such a support figure, a vitreous porous material, a sintered m
Gold M, ceramics, cellulose ester, polystyrene, vinyl butyral, polysulfone, vinyl chloride,
Examples include organic polymers such as polyester, poly7-crylonitrile, and polyamide.

Polysulfone membranes have particularly good performance as substrates for the present invention, and polyacrylonitrile is also effective. A method for making polysulfone porous substrates is also described in U.S. Salt Water Service (O8W Report) A 359.

Such substrates generally have surface pore sizes of about 50-10,
000 angstroms, preferably 100-1,00 angstroms
The diameter of the surface pores is preferably between 0 angstroms, but not limited to this (depending on the final use of the membrane, etc., the diameter of the surface pores can vary between 50 angstroms and 5,000 angstroms). These substrates can be used in either symmetrical or asymmetrical structures, but asymmetrical structures are preferable.

However, these base materials have an air permeability of 20 to 3000 seconds, more preferably 50 to 1000 seconds, as measured by a JIS P8117 device. If the air permeability is 20 seconds or less, defects are likely to occur in the resulting composite membrane, and selectivity is likely to decrease. Also, is it possible to obtain anything longer than 3000 seconds? However, only composite membranes with low air permeability can be obtained.

Further, it is advantageous for the substrate (microporous membrane) to have a maximum pore size of 1 μm or less, preferably 0.5 μm or less.

Further, the shape of the support may be various depending on the shape of the intended separation membrane, and specific examples thereof include a flat plate, a tube, and a hollow fiber. Although the thickness of the support is not limited, it is usually 10 pm to I Om, preferably 50 am to lOO'0 μm.

A polyaminopolysiloxane having only an amino group as a functional group is a polysiloxane having two or more amino groups, and is represented by the following formula (I) ■ (CH,)n . . . (I)
It is a polysiloxane having at least two units represented by the following in its molecule and at least two ÷5t-0 bonds in its molecule.

More specific examples of such compounds include the following.

・・・・・・・・・(II) R,R.

More specifically, the following are particularly preferred.

CH, CM, CH.

l l 1. 4
Goods.

N.H.

C.F.

Cheers N.H.

Nl(.

CH, CH.

I CH, CH.

N.H. ■ (CM?)8 N.H.

During ~ N.H.

CH, C, H, CH.

CH, CH-CH, 0H3 NHL Y・ N.H. (CH2)3 N.H.

N.H.

These compounds can be used alone or as a mixture of two or more.

From the viewpoint of the strength of the formed film, it is preferable that the film has a crosslinked structure, and therefore, among such polyaminopolysiloxane compounds, compounds having three or more -class and/or secondary amine groups are particularly suitable.

In addition, polyamines containing less than or equal to 7 primary and/or secondary amide groups (both having 2 groups and not having siloxanes, such as ethylenediamine, hexamethylenediamine, triethylenetetramine, polyethyleneimine, polybiyl/ L-7i y#o71'ti yN
! I 7 s y・7′° “Go Sanjiamin,
Alicyclic polyamines such as piperazine, metaphenylenediamine, 4+4'-diaminodiphenylmethane, 3.
Aromatic polyamines such as 4'-diaminodiphenyl ether and polyaminostyrene can be added. The polyamine preferably accounts for 50 moles or less of the total amine component.

Examples of the polyhydroxypolysiloxane having two or more silanol groups include compounds represented by the following general formula (v).

R,,R,OR,0 Rho Rho R+.

Examples of such compounds include the following:

CHs CHa CHs II I CH, CH2O)Is These can be used alone or as a mixture of 211 or more.

Furthermore, from the viewpoint of solubility, it is preferable that X is small;
Further, from the viewpoint of the strength of the film, a larger one is preferable. The preferred range of X is 10 to 3,000, more preferably 00 to 2,000. Furthermore, since alkoxy terminals and halogen terminals are easily hydrolyzed in the reaction system to become silanol group terminals, polysiloxane compounds containing alkoxy terminals or halogen terminals can also be used as reaction starting materials. Further, a polysiloxane compound having three or more silanol groups, such as a low condensate of methyltrialkoxysilane and dimethyldialkoxysilane, can also be used.

The polyisocyanate component having at least two isocyanate groups used in the present invention is a polyisocyanate having an aromatic alicyclic or aliphatic skeleton,
Examples include aromatic diisocyanates such as hatolylene diisocyanate, diphenylmethane isocyanate, naphthalene diisocyanate, and phenyl diisocyanate;
Hexane diisocyanate.

Examples include aliphatic or alicyclic diisocyanates such as meta-xylene diisocyanate and inphorone diisocyanate.

Also, the following formula 4 (where q represents an integer from 1 to 10)
It is also possible to use polyisocyanates having functionalities of 03 or higher.

Furthermore, the polyisocyanate component used in the present invention has at least one R in its structure.

R.

Simixane-based polyisocyanates having the same or different argyl group or phenyl group having 1 to 4 carbon atoms) and at least two isocyanate groups can also be used.

Examples of such oxidized polyisocyanate include the following formula (Vl) or the following formula (■) R2,R,,R,.

...(■) You can also use the expression .

Specific examples of the compound (Vl) are CH, CI(.

CH, CI (.

can be given.

On the other hand, the compound (■) can be obtained by reacting a compound represented by the following formula % with a polyisocyanate compound having at least two isocyanate groups.

As a specific example of karu (■), etc. can be given.

The polyisocyanate can also be used in the form of a mixture with other polyisocyanates. Among these polyisocyanates, it is preferable to use siloxane-based polyisocyanates in order to obtain a membrane with good oxygen permeability.

The permselective membrane (Bl in the present invention is explained above 4)
It is formed from a cylindrical xane compound component and a polyisocyanate compound, each of which undergoes the following reactions.

In the above reaction, the reactivity generally decreases in the order of fa)>(cl>fb). In particular, in the reaction between amide 7 groups and silanol groups, basic catalysts such as potassium hydroxide, sodium natoxide, potassium impropoxide, and aluminum trimethoxide are added to promote the reaction, and the reaction temperature is increased to 40°C. It is preferable to raise the temperature to ~200°C.

Furthermore, to improve the strength of the membrane, unreacted silanol groups can be crosslinked by adding a crosslinking agent. In particular, even if the reaction between the amino groups and silanol groups described above is insufficient, a durable film can be formed by adding this crosslinking agent.

As such a crosslinking agent, existing crosslinking agents used as crosslinking agents for polysiloxanes having silanol groups can be used. Suitable examples of the crosslinking agent are organosilicon compounds having two or more functional groups, such as acetoxysilane, ketoxime compounds, and alkokene compounds.

Examples include silazane amide compounds, aminoquine compounds, and titanium compounds. Specific examples include methyltriacetoxysilane, ethylacetoxysilane, and methyltriacetone oxime.

trimethylbutylene, methyltrimethoxysilane, tris(ethylhydroquinylamide))
, Mechinoj Shiran.

((CH3)3SiO), Ti (OC=CHCC
H, ), etc. can be raised.

Further, in order to increase the reactivity of the crosslinking agent, an accelerator such as alkyl titanate or diptyltin dilaurate may be added. Further, even if such a shading agent is capable of reacting with amino groups or isocyanate groups, the object of the present invention is not impaired, and the curing reaction may proceed on the contrary, which may be preferable in terms of the strength of the film.

A cross-linking agent can be used by mixing it with a polysiloxane containing silanol groups, or a solution containing a cross-linking agent can be applied after applying a solution containing a polysiloxane containing silanol groups. Although they can be reacted together, it is preferable to mix them and use them at the same time because the curing reaction will proceed more quickly.

Therefore, the selectively permeable membrane of the present invention (Bl is the most preferred,
In another embodiment, it can be said that the film has the following structural units. That is, it contains I H -8i-0-8i as a structural unit and -N-C- as a bonding unit.
Contains N-+ or all. The thickness of these selectively permeable membranes (Bl is usually 30 A to 10 am, preferably 50 A
~1μm.

More preferably, it is 100A to 0.2 μm.

The method for producing the above-mentioned separation membrane of the present invention includes applying a bath solution containing a polyamide 7 polyaxane having two or more amino groups and a polyhydroxypolysiloxane having two or more silanol groups onto an il+ support. and then contacting a solution containing a polyisocyanate compound having two or more isocyanate groups and capable of forming an interface with the polysimixane-containing solution; or (2) coating 2 on the support (5). Applying a solution containing polyaminopolysiloxane/ having 7 or more amino groups,
However, two or more Shira later! -containing a polyhydroxypolysiloxane having a polyhydroxypolysiloxane group and a polyisocyanate compound having two or more isocyanate groups, and contacting a solution that can form an interface with the polyaminopolysiloxane-containing solution; or ) The following (a), (b) on the support (4)
and (cl(a) a solution containing a polyaminopolysiloxane having two or more amino groups.

(b) A solution containing a polyhydroxypolysiloxane having two or more silanol groups.

(C) Apply any one solution (1) of the solutions containing a compound having two or more isocyanate groups, and then apply any one solution (2) of the remaining two solutions (provided that the above-mentioned solution (1) to form an interfacial reaction thin film on the support by contacting (1) with a substrate forming an interface, and then contacting one solution remaining on the interfacial reaction thin film;
A selectively permeable membrane (B
The purpose is to form l.

At that time, a solution of a polyaminopolysiloxane having two or more amino-7 groups is prepared by dissolving the compound in water.

Methanol, ethanol, improper tools.

Methyl cellulose, dioxane, ethylene glycol,
Diethylene glycol, triethylene glycol, glycerin or n-hexane, n'-decane, hexadecene, benzene, toluene.

It may be dissolved in a solvent such as xylene or a mixed solvent of two or more of these, and the concentration thereof is 10 PPI to 10
w14, preferably 100P to Swt.

In addition, for solutions of polyhydroxypolysiloxanes having two or more silanol groups, the compound may be prepared using methanol, ethanol, or inpropanol.

Methyl cellosolve, dioxane, ethylene glycol,
Diethylene glycol, triethylene glycol, glycerinone or n-hexane, n-hebutane, n-octane, cyclohexane.

n-decane, n-tetradecane 95-? Sub seven.

Benzene, toluene, xylene, carbon tetramide.

It can be dissolved in trifluorotrichlorethylene or a mixed solvent of two or more thereof (the mv is 10
P ~10 wt'g, preferably L (ha 500w1~S
It is wt%.

When using a solution containing both at the same time, a common solvent is used, the concentration is 20011P to 15wt4, preferably 500p to 5wt%, and the ratio of polyaminopolysiloxane to polyhydroxypolysiloxane is 0.01 to 5wt%.
100. Preferably, the solution may be adjusted to 0.02 to 50.

A solution containing a polyisocyanate is prepared by adding the compound to an aliphatic, alicyclic or aromatic hydrocarbon or halogenated hydrocarbon solvent having 6 to 18 carbon atoms, or a ketone solvent such as n-hexane, n-hebutane, n-octane, n-decane, tetradecane, hexadecene,
Cyclohexane, benzene, toluene, xylene. 10 pI11 in solvents such as carbon tetrachloride, trichlorethylene, methyl ethyl ketone, dibuvir ketone, etc.
It is adjusted by using a solution containing 10% to 10% by weight, preferably 5% by weight.

The selection of the solvent for each compound is performed depending on the film formation method. That is, since the film forming method of the present invention involves film formation at the interface of two liquids, a solvent system that forms an interface must be selected. Solvent systems that can form an interface are systems that separate into two phases when mixed. For this purpose, it is most desirable to use a system in which the phases do not completely dissolve, but if they form two phases even if they dissolve to some extent, they can be used, and the thin film of the present invention can be formed.

Since the film forming method of the present invention is a film forming method at an interface, it has the characteristic that a thin film can be easily achieved. That is, a defect-free film of 1 μm or less can be easily obtained.

The coating method used in the present invention may vary depending on the shape of the porous membrane support and the type of solvent system used.In other words, coating methods include dipping, roll coating, spray coating, etc. You can do it in any other way.

For example, when the support is in the form of a flat film, the method for forming the film is as follows:
After immersing the support in the solution and taking it out from the solvent and draining the liquid,
One method is to create a membrane by immersing the membrane in another solution that can form an interface with the solution and forming an interface on the porous membrane support. That J 0, ヮ□yo 24 Tsukeyo. , air, 9
□Let's meet.

In addition, when the support is in the form of a hollow fiber, it is possible to form a membrane on the outside of the hollow fiber support by sequentially immersing it in the reaction bath liquid so that the reaction solution does not enter inside, as in the case of a flat membrane, or to form a membrane on the outside of the hollow fiber support. This can be done by sequentially pouring the reaction solution inside the thread support to form a membrane. This method of forming a membrane on the inner surface of the hollow fiber is very advantageous in terms of handling of the membrane, since the formed ultrathin membrane with low mechanical strength can be handled without touching it.

After film formation, unreacted compounds or solvents can be washed with a low boiling point and/or low viscosity organic solvent or water. Moreover, heat treatment can also be performed to complete the reaction. The temperature is a temperature that does not cause deformation of the support or membrane, and is usually in the range of 200 to 50°C, and preferably 1 to 120 minutes.

The membrane of the present invention can be used to separate various gases by utilizing its excellent permeability and selectivity. For example, in a device that concentrates oxygen from air. 4.71 pieces, z
7) 7m. Iwaka□. , iF, as a treatment device for people with respiratory diseases, and for industrial purposes: separating hydrogen and carbon monoxide; efficiently concentrating helium from natural scum, and separating sulfur dioxide or carbon dioxide from exhaust gas. I can do it.

The membrane of the present invention can also be used as a pervaporation membrane for separating ethanol and water.

The present invention will be described in detail with reference to one example, but the present invention is not limited thereto.

Incidentally, in the examples, "part" represents a part where M is placed.

Example 1 A solution (11) consisting of 110.5 parts of a compound represented by the following formula (1) and 99.5 parts of etching glycol was prepared using a flat membrane-shaped polysulfone porous IX (polysulfone: Udel P 350 (1, thickness 320
μm, air permeability 2.1X 10-” cc/crd-se
c-cmH9° surface pore diameter 200A or less) was immersed for 10 minutes, then pulled up and drained.

On the other hand, 4.4'-diphenylmethanediyne)
0.5 part, i-silanol polydimethyl silaxane (average molecular weight 58,000) 0.5 part, methyltrimethoxysilane (1,005 parts, butyl tin dilaure) 0.005 part, hexadecene 50 Prepare a solution (2) consisting of 50 parts and 49 parts of hexane, and quickly immerse the flat polysulfone porous membrane after draining the liquid in it for 3 minutes,
I pulled it up, drained the liquid, and put it on.

Thereafter, it was heat-treated at 80° C. for 30 minutes, left at room temperature for 24 hours, washed with hexane and water, and air-dried to obtain a separation membrane. When the gas permeation performance of the separation membrane at 20°C was measured using a Seikaken gas permeability meter manufactured by Rika Seiki Kogyo ■, the oxygen permeation rate was 8.3 x 10-"
cc/d-set, ・c1nH9, and the oxygen/nitrogen chord selectivity was 3.6.

This membrane was set in a gas permeation cell and 3 kg/kg was added from the top of the membrane.
The operation of supplying air at i-G pressure for one hour and then draining to normal pressure was repeated 10 times, but there was no change in gas permeation performance.

For comparison, 0.5 part of 4,4'-diphenylmethane diisocyanate and 9 parts of hexadecene were used instead of solution (2).
[04
cc/crI-see-cm1117, and the oxygen/nitrogen selectivity was 1.4.

Furthermore, for comparison, the solution (1) with the concentration of the compound (+1) in I wt and the solution (2)
A separation membrane was obtained in exactly the same manner except that a wt% hexadecene solution (2'') of 4,4'-diphenylmethane diisocyanate was used instead of 4,4'-diphenylmethane diisocyanate.The oxygen/nitrogen selectivity of this membrane was 3.8. However, the oxygen permeation rate is 1.8
0-5CC/ad・sec-cmH9 is 1'-).

3h''Q4'Mlt・禾4' / -j / -zl-
d"□ IJ ) i - (When lucia xane is added,
This shows that a separation membrane with high permeability can be obtained while maintaining selectivity.

Incidentally, since the bath liquid containing terminal silanol polydimethylsiloxane and polyisocyanate produces rubbery precipitates over time, it is necessary to perform the film forming treatment quickly.

Example 2 The flat polysulfone porous membrane used in Example 1 was immersed in a 0.3 wt4 ethylene glycol solution of compound (2) represented by the following formula (2) % formula % (2) for 10 minutes, and the liquid was drained. Then, it was further immersed in a 0.1 wt% hexadecene solution of inphorone diisocyanide for 3 minutes. However, 0″°ゝ1)lffLff
i+i9J') ゝ゛'', fiK*i polydimethylsiloxane (average molecule 1t 58,
000) 0.5 parts, methyltrimethoxysilane (1,005 parts, digtyl thousand dilaurate 0.00
05 parts, toluene, 2 parts of hexane, and 97.5 parts of hexane for 3 minutes, taken out, drained, and heated to 80'C.
The membrane was heated for 30 minutes, air-dried for 24 hours, and washed with hexane and water to obtain a separation membrane.

When the gas permeation performance of this membrane was measured, the oxygen permeation rate was 3.6
C-, and the oxygen/nitrogen selectivity was 3.3.

Example 3 20 parts of polysulfone (Udel P3500),
A bath solution consisting of 57 parts of N-methylpyrrolidone, 3 parts of lithium chloride, and 20 parts of 2-methquine ethanol was extruded through an annular slit at 30°C, and solidified by immersion in water at 25°C. At this time, water was used as the core liquid.

In this way, a polysulfone hollow porous support having an outer diameter of 800 μm and an inner diameter of 500 μm was obtained. This hollow support was cut to a certain length, filled into a polycarbonate vibrator with the ends aligned, and both ends were fixed with an adhesive to obtain a hollow fiber membrane support module I. - The air permeation rate at 25°C of this hollow fiber membrane support in a dry state is 8 X 10-" Cc/crA-SeC-
It was cIrLN9.

Compound (1) used in Example 1 Q) 0.1 wtq
Pour the ethylene glycol solution of b into the inside of the polysulfone hollow fiber membrane support, and with the liquid inside,
1 kl inside? The pressure of /crA-a was maintained for 10 minutes to allow the amine solution to permeate into the porous membrane.

After draining nitrogen gas at a flow rate of 171 parts for 1 minute at flowed inside. Next, nitrogen gas was passed for 3 minutes at a flow rate of 11 parts, and after draining, the terminal silanol polydimethylsimixane (average molecular weight 58.
OO) 0.1 part, methyltrimethoxysilane 0.0
Part 01.

Dibutyl dilaurate 0.0001 part and hexa79
A solution consisting of 9.9 parts was flowed inside the hollow fiber support for 30 seconds at a linear velocity of 1 m/m. Then add 1 nitrogen in the same way.
The solution was drained for 30 seconds at a flow rate of 11 minutes, heated at 80° C. for 30 minutes, and then left at room temperature for 1 day. After that, the hollow support was washed for 24 hours by running water on the inside and outside (inside the case).
A hollow fiber separation membrane module was obtained. By separately flowing pure oxygen gas and pure nitrogen gas inside this membrane and measuring the amount of oxygen gas and nitrogen gas that passed through the membrane and came out, the permeation rates of oxygen and desired elements were determined. . As a result, the permeation performance of the membrane was determined to be 3.5 x I
Q-4cc/d-set·, m#ig, ft elementary nitrogen selectivity was 3.4.

Example 4 In Example 3, 4,4'-diphenylmethane diisocyanate and the terminal silano-JA were used separately.
yg IJ, ) / L-') 57□□8ii□iia1,.

4,4'-diphenylmethane diisocyanate 0.
05 parts, terminal silanol polydimethylsimixane 0.1
0.0 parts, methyltrimethoxysilane. A hollow fiber separation membrane module was obtained in exactly the same manner as in Example 3, except that a solution consisting of 09 parts of Oo, 0.0001 parts of dibutyl dilaurate, 50 parts of hexadecene, and 50 parts of hexane was poured into the hollow fiber support at once.

The permeation performance of this membrane is that the oxygen permeation rate is 2.8 x 10-4
cc/d-set, cmN9, and the oxygen/nitrogen selectivity was 3.3, showing almost the same performance as the membrane obtained in Example 3.

Example 5 0.5 parts of a compound represented by the following formula (3) % formula % (3), 0.5 parts of terminal silanol polydimethylsimixane (average molecular weight 11800), 99 parts of ethanol, and 0.001 parts of nitium methoxide
The flat polysulfonoporous membrane used in Example 1 was immersed for 10 minutes in a solution consisting of 0.0% and after draining the liquid.
It was immersed in a 5 wt % toluylene diisocyanate hexadecene solution for 3 minutes. After pulling it up, it was heat-treated at 80° C. for 1 hour, washed with hexane, washed with water, and dried to obtain a separation membrane.

The oxygen permeation rate of this membrane is 7.2 x 10-5cc/(
7-sec・cmu9, and the oxygen/nitrogen selectivity is 3
．． It was 3.

This membrane was installed in a gas separation cell, and air separation was performed continuously for 30 days by reducing the pressure to atmospheric pressure on the raw material gas (air) side and 160 to 170 Torr on the permeate gas side.

The oxygen permeation rate after 30 days was 7. OX 10-5cc/
crd -sec -cm fly, and the oxygen/nitrogen selectivity was 3.3, showing almost no difference from the initial performance.

Example 6 The flat polysulfone porous membrane used in Example 1 was immersed for 10 minutes in an ethylene glycol solution containing 5 wt% of a compound represented by the following formula (4). After draining the liquid, it was immersed in a -xadecene solution containing 0.5 wt% of an isocyanate compound represented by the following formula (5) for 3 minutes, and the liquid was sufficiently drained.

Thereafter, the porous membrane after draining the liquid was treated with terminal silanol polymethylphenylsiloxane (average molecular weight Ji 30.0
00) 0.5 parts, methyltrieth-1 disilane 0.
1 part of dibutyltin dilaurate, 0.0001 part of dibutyltin dilaurate, 795 parts of hexa, and 5 parts of toluene. Thereafter, a separation membrane was obtained by washing with hexane and water. The oxygen permeation rate of this membrane is 7.7 x ] 0-” cc/cr
l·set, -cmllg, and the oxygen/nitrogen selectivity was 3.3.

Example 7 A separation membrane was obtained in the same manner as in Example 6 except that the dipping order of the flat polysulfone porous membrane was changed as follows.

That is, first, polyaminopholysiloxane M i& was immersed for 10 minutes, drained, then immersed in a terminal silane, l-polysiloxane solution for 30 seconds, drained, and finally immersed in a polyisocyanate solution for 3 minutes.

The oxygen permeation rate of this membrane is 9.1 x 10” cc/
, 7·sec-cm H9, and the oxygen/nitrogen selectivity was 3.0.

Claims (1)

[Scope of Claims] Polyaminopolysiloxane compounds having only one or more amino groups as functional groups, polyhydroxypolysiloxane compounds having only two or more silanol groups as functional groups, and two or more isocyanate groups. A separation membrane consisting of a selectively permeable membrane (B) mainly formed from a polyisocyanate compound and a support (A) that supports it. 2. On the support (A), a solution containing a polyaminopolysiloxane compound having only two or more amino groups as a functional group and a polyhydroxypolysiloxane compound having only two or more silanol groups as a functional group. After that, a solution containing a polyisocyanate group having two or more isocyanate groups and capable of forming an interface with a solution containing the above-mentioned polysiloxane compound is brought into contact with the solution selected on the support (A). A method for producing a separation membrane, which comprises forming a permeable membrane (B). 3. On the support (A), apply a solution containing a polyaminopolysiloxane compound having only two or more amino groups as a functional group, and then apply a solution containing a polyaminopolysiloxane compound having only two or more silanol groups as a functional group. A solution containing a hydroxypolysiloxane compound and a polyisocyanate compound having two or more isocyanate groups and capable of forming an interface with the polyaminopolysiloxane compound-containing solution is brought into contact with the solution, and the selected material is placed on the support (A). Sexually permeable membrane (
B) A method for producing a separation membrane, characterized by forming: 4. On the support (A), the following (a), (b) and (c)
(a) A solution containing a polyaminopolysiloxane compound having only two or more amino groups as a functional group, (b) A solution containing a polyhydroxypolysiloxane compound having only two or more silanol groups as a functional group, ( c) Apply any one solution (1) of the solutions containing a polyisocyanate compound having two or more isocyanate groups, and then apply any one of the remaining two solutions (2) to the coating solution. (
However, a substance capable of forming an interface with the solution (1) is brought into contact with the solution (1) to form an interfacial reaction thin film on the support (A),
A method for producing a separation membrane, which comprises: thereafter bringing the remaining solution (3) into contact with the interfacial reaction thin membrane to form a selectively permeable membrane (B).