JPH078768A - Manufacture and device for gas permeable hollow fiber membrane - Google Patents

Abstract

PURPOSE:To control the lowering of performance with time without deteriorating the initial gas permeability by forming a Langmuir-Blodgett film layer on the surface of a hollow fiber membrane composed of poly(substituted acetylene), irradiating the surface of the film layer with energy beam and fixing the same. CONSTITUTION:A hollow fiber membrane is formed by poly(substituted acetylene) of a structural formula represented by formula (R represents 1-4C alkyl.). Thus manufactured hollow fiber membrane alone represents the superior gas permeability, but its characteristics are lowered with time. To avoid such a trouble, Langmuir-Blodgett film layers of an reactive monomer of its oligomer are laminated on the surface of the hollow fiber membrane, irradiated with energy beam and solidified. An extremely thin polymer film layer is formed on the surface of hollow fiber membrane. Therefore, the gas permeating film having a stabilized gas permeability for a long time can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a gas permeable hollow fiber membrane and an apparatus for producing the same.

[0002]

2. Description of the Related Art In the separation and purification of gas, a method using a gas permeable polymer membrane has attracted attention because of energy saving. Oxygen-enriched air separated and produced from air using this type of polymer membrane is expected to be used for energy saving due to its improved combustion efficiency, reduction of harmful substances emitted due to complete combustion, and utilization for animal and plant growth. There is.

In view of the above-mentioned applications, a high gas permeability is one of the performances that this kind of polymer membrane should have.
High gas separation property (ratio of permeability between gas to be separated and gas not to be separated) is high. In particular, in consideration of applications and the like, high gas permeability is strongly required. A poly-substituted acetylene represented by the structural formula represented by Chemical Formula 3 is a material that most satisfies such performance.

[0004]

[Chemical 3]

This material is soluble in certain organic solvents and is a normal polymer film (eg polydimethylsiloxane).
The gas permeability is remarkably superior to that of the above, and the gas permeability coefficient is larger by one digit or more.

On the other hand, in order to further enhance the high gas permeability of the membrane, it is desirable that the membrane has a hollow fiber shape. In this case, when a gas permeation cell is assembled using the above-mentioned polymer membrane, the surface area of the membrane per unit volume of the cell can be increased, so that the gas permeation amount can be increased. Therefore, it can be said that making the poly-substituted acetylene membrane into a hollow fiber is a means for producing a gas permeable cell having the best gas permeability.

However, this poly-substituted acetylene film has a property that the gas permeability is lowered with time, and the gas permeability after a long time is equal to or lower than that of an ordinary polymer film. Will end up. It is considered that this is because the non-volatile components in the air are adsorbed on the surface of the poly-substituted acetylene film to prevent the gas from dissolving.

In order to solve this, conventionally, a method of laminating another polymer film on the surface of the poly-substituted acetylene film so that the surface of the poly-substituted acetylene film does not come into contact with air has been considered. However, in the case of this method, unless the thickness of the polymer film to be laminated is remarkably thin with respect to the thickness of the poly-substituted acetylene film, the high gas permeability of the poly-substituted acetylene film will be offset, It's not convenient.

Further, as a method for producing an ultrathin film of a poly-substituted acetylene film and a polymer film laminated thereon, a water surface development method has been conventionally used. In this case, the film developed on the water surface is scooped up by a substrate. Therefore, the resulting membrane necessarily has a flat membrane shape, and it is difficult to form a hollow fiber shape.

Further, a method may be considered in which a hollow fiber is first made of poly-substituted acetylene and the hollow fiber is dipped in a polymer solution to be laminated. The thickness cannot be reduced to a certain level or less, and the demand for thinning cannot be sufficiently satisfied.

Alternatively, a method of forming a laminated film on a hollow fiber formed of poly-substituted acetylene by a vacuum method (vacuum vapor deposition, sputtering, plasma polymerization, etc.) can be considered. It takes a long time from the formation to the formation of the laminated film, and during that time, the gas permeability of the poly-substituted acetylene is impaired.

[0012]

DISCLOSURE OF THE INVENTION The present invention is to form a very thin thin film layer on the surface of a polymer hollow fiber membrane made of polysubstituted acetylene so that the initial gas permeability is not impaired as much as possible and the aging is performed. The present invention aims to produce a gas-permeable hollow fiber membrane in which the deterioration of the performance is suppressed.

[0013]

According to the present invention, a hollow fiber membrane made of poly-substituted acetylene is dipped in a liquid in which a Langmuir-Blodgett film has been prepared in advance, and the Langmuir-Blod surface is formed on the surface of the hollow fiber membrane. The jet film layer is formed, and then the surface of the Langmuir-Blodgett film layer is irradiated with an energy beam to immobilize the Langmuir-Blodgett film layer.

[0014]

The polysubstituted acetylene in the present invention is obtained by polymerizing a disubstituted acetylene represented by the chemical formula 4 below.

[0015]

[Chemical 4]

The polymer is TaC15, NbC15, Ta.
Group V transition metal catalysts such as Br5 and NbBr5 and solvents such as aromatic hydrocarbons (benzene, toluene, xylene, etc.), alicyclic hydrocarbons (cyclohexane, etc.), halogenated hydrocarbons (carbon tetrachloride, trichloroethylene, etc.) Obtained by heating at 30 to 100 ° C. in an inert gas.

The obtained polymer is used as a solvent in aromatic hydrocarbons (benzene, toluene, xylene, etc.), alicyclic hydrocarbons (cyclohexane, etc.), halogenated hydrocarbons (carbon tetrachloride, trichloroethylene, etc.), etc. Dissolve and use this solution as the spinning dope. Stock solution concentration is 1-10
% Is preferable.

An asymmetric hollow fiber membrane is formed from this spinning dope. This formation is performed as follows. First of all, the spinning dope from the outer tube part of the nozzle whose outlet has a double tube structure,
Further, a liquid (coagulating liquid) which is mixed with the solvent of the spinning dope without dissolving air, a gas such as nitrogen, or a poly-substituted acetylene is simultaneously extruded from the inner tube portion. As the coagulating liquid, alcohols such as methanol, ethanol and propanol, glycols such as ethylene glycol and diethylene glycol are used.

The extruded spinning solution is preliminarily dried for an arbitrary time or distance and then introduced into the coagulating solution. The spinning solution is desolvated in the coagulating solution to form a hollow fiber, which is then taken out from the coagulating solution to evaporate the solvent. As a result, a hollow fiber membrane can be obtained.

The hollow fiber membrane thus obtained has a dense layer with no physical pores on the outside and a porous sponge structure toward the inside. That is, this inner portion serves as a support layer having little mechanical involvement in gas permeation and mechanical strength.

During this step, the thickness of the dense layer and the pore diameter of the supporting layer can be adjusted by adjusting the type of gas or coagulating liquid extruded together with the spinning dope, predrying time, temperature, coagulating liquid temperature, dipping time and the like. , Hole distribution, etc. can be adjusted.

The obtained hollow fiber membrane shows excellent gas permeability by itself, but its properties tend to deteriorate with time.
To avoid this, first the Langmuir-Blodgett (hereinafter simply referred to as L
It is called B. ) Membranes are accumulated on the surface of this hollow fiber membrane and then irradiated with an energy beam to immobilize this LB layer. As a result, an extremely thin polymer membrane layer is formed on the surface of the hollow fiber membrane.

This LB membrane can be laminated on the surface of the hollow fiber membrane by the LB method. The process is performed as follows. That is, on the water surface partitioned by the barrier, the reactive monomer or its oligomer or its solution is developed in an appropriate amount to form a water surface film, and then the barrier is moved to control the water surface film pressure to an appropriate water surface film pressure. The hollow fiber membrane is immersed in water from above the water surface membrane to transfer the water surface membrane to the surface of the hollow fiber membrane. This makes it possible to form an extremely thin reactive monomer or its oligomer layer on the surface of the hollow fiber membrane.

Examples of the reactive monomer or oligomer thereof used herein include vinyl group-containing reactive monomers or oligomers such as styrene and N-vinylpyrrolidone, and acrylic groups such as trimethylolbropane triacrylate. One or more of reactive monomers or oligomers thereof, methacrylic group-containing reactive monomers such as trimethylolpropane trimethacrylate or oligomers thereof, and the like can be used. Particularly, in the case of a reactive monomer having a siloxane bond or fluorine in the molecule or its oligomer, it is advantageous in that the gas permeability is excellent as compared with other reactive monomers or its oligomer by curing.

The surface of the laminated film thus formed is subsequently irradiated with an energy beam to fix the LB film layer. As the energy beam, radiation such as electron beam and gamma ray, and electromagnetic wave such as ultraviolet ray can be used. Generally, it is desirable to use an electron beam. This is advantageous because it is easy to operate and can be processed in a short time. In this case, the acceleration voltage of the electron beam is 50 kV
Or more, preferably 100 kV or more, and as an absorbed dose, 0.1 to 150 megarad, preferably 0.1 to 1
It is 0 megarad.

Even when gamma rays are used, the same level of absorbed dose is preferable, but if the dose is too high, the irradiation time becomes long and the efficiency is not very good. More preferably 0.1
It is about 10 megarads.

When electromagnetic waves such as ultraviolet rays are used, for example, as the ultraviolet rays, light having an arbitrary wavelength of 10 nm to 400 nm is used. As a UV source, commercially available UV
A curing device, a high-pressure mercury lamp, a UV lamp for an analytical detector, etc. are used. The irradiation intensity at this time is 1 cm 2.
Per mW is more preferred. In this case, it is convenient to add an appropriate amount of the photoreaction sensitizer to the LB film because the reaction proceeds efficiently.

Examples of the photoreaction sensitizer include 2-isobromopyrthioxanthone, 2.4-diethylthioxanthone, benzyl dimethyl ketal, 2.4.6 trimethylbenzophenone, α-ethoxy-α-phenylacetophenone and α-isopropoxy. Appropriate ones such as -α-phenylacetophenone, ethyl-4- (dimethylamino) benzoate, 2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone are used.

[0029]

【Example】

Example 1 A viscous polymer gel was obtained by reacting 1- (trimethylsilyl) -1-bropine (Aldrich) 1 g, TaC 150.06 g, and toluene 10 cc at 80 ° C. for 24 hours in a nitrogen atmosphere. It was This polymer gel was diluted with toluene and then dropped into a large amount of methanol to precipitate and precipitate the polymer. The polymer obtained was filtered and dried.

2 g of the obtained polymer was added to 100 cc of toluene.
To obtain a polymer solution. 40 parts of this polymer solution
After filtering through a 0 mesh stainless steel filter, the mixture was discharged into the air at a rate of 5 cubic cm per minute through a double tube type hollow fiber nozzle. At this time, methanol was discharged at the same rate from the nozzle inner tube.

Subsequently, the discharged polymer solution was dipped in a methanol coagulating liquid tank installed at a position 10 cm from the nozzle, held for 10 minutes, and then pulled up and dried. The obtained hollow fiber membrane had an outer diameter of 900 μm and an inner diameter of 500 μm.

Next, a 1 Wt% chloroform solution of silicone acrylate (made by Gold Schmidt) was developed with a syringe on the water surface of the LB film manufacturing apparatus filled with water,
The hollow fiber membrane was immersed while controlling the barrier so that the membrane pressure was 30 dyn / cm. This operation was repeated twice to form a two-layer laminated film of the polymer film and the silicone acrylate. The obtained two-layer laminated film was irradiated with an electron beam under the conditions of an accelerating voltage of 200 kV and an absorbed dose of 0.1 megarad by an area beam type electron beam irradiation device to be cured.

Example 2 A hollow fiber membrane was prepared in the same manner as in Example 1, followed by silicone acrylate (manufactured by Gold Schmidt) and α-.
A 1 wt% chloroform solution of an ethoxy-α-phenylacetophenone mixture (weight ratio 100: 1) was developed with a syringe on the water surface of an LB membrane manufacturing apparatus filled with water, and a barrier was applied so that the membrane pressure became 30 dyn / cm. The hollow fiber membrane was immersed while controlling with. Repeat this operation twice,
Polymer film and silicone acrylate / α-ethoxy-α
A two-layer laminated film of a phenylacetophenone mixture was formed. The obtained two-layer laminated film was irradiated with a metal halide lamp type ultraviolet irradiation device at an irradiation intensity of 20 m per square cm.
UV light was applied for 1 second at W.

The performance evaluation of the hollow fiber membranes of each of the above examples was carried out by trial-making a tubular module (volume: about 71 cubic cm) having a diameter of 3 cm and a length of 10 cm. That is, after sealing a large number of ends of the hollow fiber membrane of each example, the hollow fiber membrane was assembled into a tubular module, and oxygen or nitrogen was added to the outside of the hollow fiber,
Flowing at a constant pressure of 1 kgf per square cm, the gas flow rate coming out from the inside of the hollow fiber was measured by a membrane flow meter.

Comparative Example A 20 wt% benzene solution of polydimethylsiloxane was used to form a hollow fiber membrane in the same manner as in the example. The obtained hollow fiber membrane had an outer diameter of 900 μm and an inner diameter of 500 μm. This was directly incorporated into the tubular module.

The gas permeation flow rate for the membranes of the above examples,
Table 1 shows the oxygen permeation rate (Ro2) and the gas separation degree α. In each example, the performance immediately after the irradiation of the energy beam is set as the initial value. The gas separation degree α was calculated from the oxygen / nitrogen separation degree.

[0037]

[Table 1]

As is clear from the results shown in Table 1, the module using the polymer hollow fiber membrane according to the example has gas permeation while maintaining stable characteristics for a long time, as compared with the module according to the comparative example. It is found that the flow rate exhibits extremely large characteristics.

Next, the manufacturing apparatus according to the present invention will be described with reference to FIGS. The manufacturing apparatus shown in FIG.
It is mainly composed of a hollow fiber membrane production section A, an LB membrane lamination section B, and an energy beam irradiation section C. The hollow fiber membrane producing section A has a tank 1 in which a spinning stock solution is stored, and the spinning stock solution in the tank 1 is sent by a pump 2 at a constant flow rate. The spinning dope delivered by the pump 2 is discharged from the double tube type nozzle 3. The discharged spinning solution is preliminarily dried by the predrying device 4.

A coagulating liquid tank 5 is filled with a coagulating liquid. The spinning dope that has been pre-dried by the pre-drying device 4 is immersed in the coagulation bath 5 and desolvated to form a hollow fiber membrane structure. A gas such as air and nitrogen, or a gas such as a coagulating liquid is stored in the tank 6, and the pump 7 discharges the gas from the inner tube of the double-tube nozzle 3 into the spinning solution. The solvent of the spinning dope is evaporated from the inside of the hollow fiber membrane by these gas and coagulating liquid.

The hollow fiber membrane T thus obtained is then sent to the LB membrane stacking section B. The LB film stacking section B is provided with a water tank 8 on which the LB film is developed, and a tank 9 storing the LB film material sends the water to the surface of the water tank 8 via a nozzle 11 by a pump 10. Come on. Aquarium 8
A sensor 12 for measuring the surface pressure of the LB film and a barrier 13 for compressing the LB film are provided on the surface of the.

Sensor 12, barrier 13 and pump 10
Is connected by a control circuit, and when the LB film on the surface of the water tank 8 is kept at an arbitrary constant surface pressure and the developed area becomes smaller than an arbitrary value, the LB film material is pumped from the tank 9 by a pump 10 To replenish and maintain the surface pressure by interlocking with the barrier 13.

As described above, the hollow fiber membrane T is sent from the hollow fiber membrane producing section A in a state where the LB membrane is developed on the surface of the water tank 8 and is compressed by the barrier 13 and adjusted to an arbitrary constant surface pressure. And is immersed in the LB film layer. The immersed hollow fiber membrane T is folded back along a roll 14 provided in the water tank 8, passes through the LB membrane layer again, and is discharged into the atmosphere. As a result, the LB membrane is laminated on the surface of the hollow fiber membrane T. In this case, depending on the material of the LB film, the compression pressure, etc., the LB layer is laminated as one layer or two layers.

The hollow fiber membrane on which the LB membrane is laminated is immediately sent to the energy beam irradiating section C and irradiated with the energy beam. The energy beam source,
For example, the electron beam irradiator 16 is installed very close to the hollow fiber membrane outlet of the water tank 8, and the sent hollow fiber membrane T is immediately irradiated with the electron beam. As a result, the LB membrane on the surface of the hollow fiber membrane T is fixed. The hollow fiber membrane T irradiated with the electron beam is continuously wound by the winding drum 16.

[0045]

As described above in detail, according to the present invention, in obtaining a gas permeable membrane using poly-substituted acetylene as a raw material, this kind of gas permeation as a hollow fiber membrane and exhibiting stable gas permeation performance for a long period of time is obtained. A flexible film can be manufactured. Further, according to the apparatus of the present invention, there is an effect that this hollow fiber membrane can be continuously manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a side view of a portion of FIG.

[Explanation of symbols]

 A Hollow fiber membrane production department B LB membrane lamination part C Energy beam irradiation part 1 Tank 2 Pump 3 Double tube nozzle 4 Drying part 5 Condensation liquid tank 8 Water tank 9 Tank 10 Pump 12 Sensor 13 Barrier 15 Energy beam source 16 Winding drum

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location D01F 6/26 7199-3B 11/06 // B01D 71/70 500 9153-4D

Claims (2)

[Claims] 1. The structural formula is: In the step of forming a hollow fiber membrane from poly-substituted acetylene represented by the following, the hollow fiber membrane is immersed in a liquid in which a Langmuir-Blodgett membrane is prepared, and the surface of the hollow fiber membrane layer is coated with the Ngumuir-broth. It comprises a step of forming a jet membrane layer and a step of irradiating the Langmuir-Blodgett membrane layer on the surface of the hollow fiber membrane with an energy beam to immobilize the Langmuir-Blodgett membrane layer. A method for producing a gas-permeable hollow fiber membrane. 2. The structural formula is: A tank for storing a spinning stock solution composed of poly-substituted acetylene, a double tube type nozzle for discharging the spinning stock solution from the tank to form a hollow fiber shape, and a hollow fiber type discharged from the double tube type nozzle The spinning stock solution is sent, the coagulation bath filled with the coagulation bath, and the hollow fiber membrane obtained by being immersed in the coagulation bath is delivered, and the layer of Langmuir-Blodgett film is spread on the surface. The Langmuir-Blodgett film is fixed by irradiating an energy beam on the surface of the hollow fiber membrane having the Langmuir-Blodgett film laminated on the surface through the water tank And a take-up drum for continuously winding the energy beam irradiating section and the hollow fiber membrane irradiated with the energy beam by the energy beam irradiating section. Apparatus for producing a gas-permeable hollow fiber membranes made of.