JPS60127332A - Anion exchange membrane and its manufacture - Google Patents

Abstract

PURPOSE:To obtain titled membrane in high efficiency, suitable as separating membranes for Glauber's salt electrolysis etc., by graft polymerization of alpha,beta,beta- trifluorostyrene to ionizing radiation-irradiated inert polymer film followed by haloalkylation and quaternary amination. CONSTITUTION:An inert polymer film with radical generated by irradiating ionizing radioactive rays (pref. with a dose of 1-30Mrad) (pref. polyethylene film) is immersed in or brought into contact with alpha,alpha,beta-trifluorostyrene (TFS) (solution) (pref. made to react at 10-90 deg.C for 1-50hr) to effect graft polymerization of said TFS followed by haloalkylation with chloromethyl ether etc. and quaternary amination with trimethylamine etc., thus obtaining the objective membrane with said TFS representing grafted chain and at least part of the benzene rings substituted by quaternary aminoalkyl groups. EFFECT:Free from the polymerization and deterioration of the TFS. Short in radioactive ray-irradiation time, thus enough with a small amount of dose.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anion exchange membrane that can be used as a diaphragm in various applications such as mirabilite electrolysis, water electrolysis, seawater desalination, and electrodialysis, and a method for producing the same.

A graft polymer membrane consisting of an inert polymer film having α, β, β ~ trifluorostyrene (hereinafter referred to as TFS) as a graft chain is known, and after being sulfonated, the graft polymer membrane is used for salt electrolysis. It is used for fuel cells (JP-A-51-89881). This kraft polymer film is produced by immersing or contacting an inert polymer film in an inert organic solvent solution of TFS.
It is manufactured by irradiating with Co or the like and graft polymerizing TFS. However, in order to produce a graft-polymerized film with a grafting rate of about 15%, this method requires continuous irradiation for about 240 hours, which results in low productivity and poor salmon processing efficiency, and also exposes TFS to radiation. For irradiation, TF
Various drawbacks have been pointed out, such as homopolymerization of S itself, a decrease in the grafting rate, and deterioration of TFS.

The present inventors investigated substitutions other than sulfonation of the above-mentioned graft polymer membrane, and found that when the graft polymer membrane was subjected to quaternary aminoalkylation, 3! It has been found that it can be used as an anion exchange membrane with the purpose of increasing electricity.

Furthermore, the present inventors investigated various economical methods for manufacturing the above-mentioned anion exchange membrane that do not cause TFS homopolymerization or deterioration, and found that only an inert polymer film is ionizable. Irradiation with radiation generates 2 radicals,
The film in which radicals have been generated is immersed in or brought into contact with TFSt or a solution thereof to undergo graft polymerization, followed by haloalkylation and quaternary amine formation, thereby efficiently producing the above cation exchange membrane. He found out.

That is, the present invention firstly provides a graft polymer film comprising an inert polymer film having α, β, β-trifluorostyrene as a graft chain, in which at least a portion of the benzene rings are converted into quaternary aminoalkyl groups. Second, it is an anion exchange membrane consisting of an inert polymer film having α, β, β-trifluorostyrene as a graft chain. -afP
When producing an anion exchange membrane in which a decoy tin is substituted with a 7-minoalkyl group, an inert polymer film is irradiated with ionizing radiation, and the irradiated film is immersed in α, β, β-trifluorostyrene or a solution thereof. Alternatively, there is a method for producing an anion exchange membrane in which graft polymerization is carried out through contact, and then the graft polymerized membrane is subjected to haloalkylation and then quaternary amine formation.

The inert polymer film used in the present invention may be made of a hydrocarbon polymer, a fluorine-containing hydrocarbon polymer, a perfluorohydrocarbon polymer, etc., and may be a homopolymer or a copolymer, for example. ,
Polyethylene-polytetrafluoroethylene copolymer film, polychlorotrifluoroethylene film, polyvinylidene fluoride film, polyvinyl fluoride film, tetrafluoroethylene-hexafluoropropylene copolymer film, tetrafluoroethylene-ethylene copolymer A composite film, a tetrafluorotetraethylene-perfluoroalkyl hinyl ether copolymer film, and a chlorotrifluoroethylene-ethylene copolymer film are selected. Further, these films may have fine pores.

The radiation irradiated to this inert polymer film may be any radiation that generates radicals in the film, and various ionizing radiations may be used. The dose of ionizing radiation to be irradiated varies depending on the material of the inert polymer film, but is preferably 1 to 30 Mrad. Irradiation amount is 1
If it is less than Mrad, the progress of graft polymerization will be insufficient, and if it exceeds 30 Mrad, the membrane function will deteriorate, which is not preferable. Irradiation can be performed in air, in an oxygen atmosphere, or in a nitrogen atmosphere. The radical rays generated on the irradiated film have a lifespan of about 2 weeks at 0℃, about 1 week at 10℃, and 2 to 3 days at room temperature in an inert gas atmosphere, and can be transferred to other places after irradiation. This is convenient because it can be transported and graft polymerization, which will be described later, can be carried out.

Next, graft polymerization of TFS onto the irradiated film is performed. Chloroform, methylene chloride, carbon tetrachloride, 1.1
, 2.2-tetrachloroethane, 1,1.2-) dichlorotrifluoroethane, TFS dissolved in a solvent such as benzene, or immersed in TFS not dissolved in a solvent, or TFS is brought into contact with the irradiated film by coating it, etc., and the reaction is carried out at a reaction temperature of 10 to 90° C. and a reaction time of 1 to 50 hours. In this case, there is no need to add any other catalyst, and the reaction proceeds simply by immersion in or contact with TFS, and a graft polymerized membrane is produced with a grafting ratio of 10 to 50%.

Graft rate @)==777yoichi! Lili (Ni-nosashi Kizuna Shi Y Yugiri!! Lx 1o.

Weight of Base Film Next, the grafted heavy metal film produced as described above is subjected to haloalkylation.

Examples of the haloalkyl group include chloromethyl, bromomethyl, iodomethyl, and chloroethyl. The haloalkylating agent depends on the type of haloalkyl group, but in the case of chloromethyl, chloromethyl ether (CHsOCHzC/), paraformaldehyde ((CHIO)s), hydrogen chloride, etc. can be used. For the method of introducing haloalkyl groups, known means may be used as is. When chloromethyl ether is used as the haloalkylating agent, the graft polymerized membrane is immersed in chloromethyl ether containing a catalytic amount of aluminum chloride. The reaction is carried out at -80°C for 1 - 20 hours, and when paraformaldehyde is used, panformaldehyde and hydrogen chloride are reacted at 40 - 80°C using zinc chloride as a catalyst in the graft polymerized membrane.

The chloromethylation rate after the reaction is 10 to 100%.

Next, this graft polymerized membrane is immersed in benzene etc. to create some grooves, and then immersed in a 5-50% tertiary amine aqueous solution and reacted at 40-70°C for 2-10 hours to perform anion exchange. Make it a membrane. As the tertiary amine, trimethylamine, triethylamine, N,N-dimethyl-2-hydroxyethylamine, etc. can be used. The ion exchange capacity of the anion exchange membrane manufactured in this way is
0.6~2.0 meq/?・It is a dry film.

The anion exchange membrane according to the present invention can be used as various diaphragms for mirabilite electrolysis, water electrolysis, seawater desalination, electrodialysis, and the like.

In addition, according to the method for producing an anion exchange membrane according to the present invention, an inert polymer film is irradiated with ionizing radiation to generate radicals in the film, and then immersed in or brought into contact with TFS to carry out graft polymerization. If the graft polymer film is haloalkylated and quaternary aminated, TFS will not be irradiated with radiation, so polymerization and deterioration of TFS will occur.Also, under radiation irradiation,
Since TFS is not graft-polymerized onto an inert polymer film, the radiation irradiation time is short and the amount of radiation consumed is low, making it an economical and safe method.

Examples of the present invention are described below, but the present invention is not limited to these Examples.

Example 1 A low-density polyethylene film with a thickness of 100 μm was irradiated with 10 Mrad in a nitrogen atmosphere using a resonant transformer type electron beam accelerator under irradiation conditions of 2 MV + 1 mA. Next, this irradiated polyethylene film was placed in a reactor for 10'■
After degassing under HP reduced pressure, α,β,β-trifluorostyrene from which dissolved oxygen had been previously removed by freeze-degassing was injected into the reactor, and the irradiated polyethylene film was
While immersed in β, β-trifluorostyrene,
The reaction was allowed to proceed at room temperature for 200 hours. After the reaction, the grafted film was taken out from the container and washed with n-hexane.
The grafting rate of the dried graft polymerized membrane thus obtained was 23%.

This graft polymerized membrane was immersed in chloromethyl ether containing a catalytic amount of aluminum chloride, reacted at 58° C. for 6 hours, and then washed with 1011I hydrochloric acid and then with distilled water. The chloromethylation rate of the graft membrane thus obtained was 80g6.

The graft polymerized membrane after chloromethylation was placed in benzene for 30 min.
After being immersed for a minute to swell, it was immersed in a 30% aqueous solution of trimethylamine and reacted at 50° C. for 4 hours.

The ion exchange capacity of the anion exchange membrane thus obtained was 0.86 meq/f/dry membrane.

This anion exchange membrane was heated to 0.6 N K (in J at 20°C, 1
The membrane resistance measured at KHz alternating current was 4.2 Ωd, and the transference number u 0.92 was measured at 0.5 N KCI/1.0 N MCI.

When this anion exchange membrane was immersed in distilled water at 95°C for 6 days, the weight loss rate of the membrane was 0%, and the membrane resistance and transport number were almost the same as before the heat treatment.

Example 2 An anion exchange membrane was obtained in exactly the same manner as in Example 1, except that a polyvinylidene fluoride film with a thickness of 100 μm was used. At this time, the grafting rate was 2°, the chloromethylation rate was 78%, and the ion exchange capacity was 0.75 meq.
/f・It was a dry film.

Kono anion exchange membrane in 0.6NKC1 at 20℃, 1KH
The membrane resistance measured with alternating current of z is 5. QQd is j7.0.
5NKCl/1.0NKClMeasured transference number ti 0.
93 There was te.

This anion exchange membrane was soaked in distilled water at 95°C for 6 days.
The membrane resistance and transport number #l were also the same as before the heat treatment.

Example 3 A 25-μ thick tetrafluoroethylene-ethylene copolymer film was irradiated with 10 Mrad in the same manner as in Example 1. Then, this irradiated film was placed in a reactor for 10 minutes.
α,β,β-trifluorostyrene solution (α,β,β-trifluorostyrene 50 parts, 1,1. 2-) Rechlorotrifluoroethane 50
The irradiated film was graft-polymerized at 50° C. for 6 hours while immersed in α, β, β-trifluorostyrene. After the reaction, the grafted film was taken out from the container, washed with n-hexane, unreacted monomers were extracted and removed, and then dried. The graft ratio of the graft polymerized membrane thus obtained was 18.

This graft polymerized membrane was immersed in chloromethyl ether containing a catalytic amount of aluminum chloride, heated at 58 DEG C. for 6 minutes, submerged with 1O4 hydrochloric acid for 1-2 times, and washed with distilled water. The chloromethylation rate of the graft polymerized membrane thus obtained was 80%.

FIG. 1 is an infrared absorption spectrum of the graft polymerized film after chloromethylation. Since absorption due to stretching vibration of C--C was observed at 790 cm-'', chloromethylation was confirmed.

The graft polymerized membrane after chloromethylation was placed in benzene for 30 min.
After being immersed for a minute to swell, it was immersed in a 30% 0% trimethylamine solution and reacted at 50°C for 4 hours.

FIG. 2 shows the infrared absorption spectrum (y) of the graft polymerized membrane (anion exchange membrane) after amination. Absorption due to stretching vibration of active methylene was observed at 1480t1m'', which confirmed amination.

In addition, absorption of water contained in the anion exchange membrane was observed at 3600 cm-'' and 1640 cm-''.

The ion exchange capacity of the anion exchange membrane thus obtained was 0.7 meq/f/dry membrane.

This anion exchange membrane was heated at 0.6 N K (J at 20°C,
The membrane resistance measured at 1KHz AC is 4.80d,
The transference number measured with 0.5 N KCl/1.0 N KC) was 0.94. When this anion exchange membrane was immersed in distilled water at 95° C. for 6 days, the weight loss rate of the membrane was 0 for #1, and the membrane resistance and transport number were almost the same as before the heat treatment.

Example 4 A tetrafluoroethylene-ethylene copolymer film having a thickness of 25 μm was subjected to graft polymerization and chloromethylation in exactly the same manner as in Example 3 to obtain a graft polymer film. At this time, the grafting rate was 18, and the chloromethylation rate was #'i8.
It was 0chi.

The graft polymerized membrane after chloromethylation is N,N-dimefk
It was immersed in -2-hydroxyethylamine and reacted at 50°C for 6 hours.

The ion exchange capacity of the anion exchange membrane thus obtained was 0.7 meq/f/dry membrane.

This anion exchange membrane was incubated in 0.6 N KCI at 20°C for 1
The membrane resistance measured at KHz alternating current is 5.20d and 0
, 5 N KCl/1.0 N KCJ was 0.95. This anion exchange membrane was soaked in distilled water.
When immersed for 6 days at 5℃, the weight loss rate of the membrane was #
1 was 0 chi, and the membrane resistance and transference number were also the same as before the heat treatment.

Example 5 An anion exchange membrane was obtained in exactly the same manner as in Example 3, except that a polytetrafluoroethylene film with a thickness of 100 μm was used. At this time, the grafting rate was 18%, the chloromethylation rate was 80%, and the ion exchange capacity was 0.71m.
eq/f/dry film.

This anion exchange membrane was heated to 20C11K in 0.6 NKCJ.
The membrane resistance measured at Hz alternating current was 6.00 d, 0.
5N K (J/1.0 NK (The transference number measured in J is 0.
There was 93-t'.

When this ion exchange membrane was immersed in distilled water at 95° C. for 6 hours, the weight loss rate of the membrane was tltz 0 *, and the membrane resistance and transport number were also the same as before the heat treatment.

Comparative Example 1 An anion exchange membrane prepared by treating a commercially available copolymer film of divinylbenzene and vinylbenzene chloride with trimethylamine was immersed in distilled water at 95°C for 6 hours, and the weight loss rate was 1.0 cm. Met. Also, the membrane resistance (0.6NKCJ) is 2.16Ωd before heat treatment.
1 After the heat treatment, the tl was 2.110 d, which was the same level, but the transference number (0.5NKCl/1°0 NKCl) decreased to 0.94 before the heat treatment and 0.92 after the heat treatment.

[Brief explanation of drawings]

FIG. 1 shows the infrared absorption spectrum of the graft polymerized membrane after chloromethylation in Example 4 of the present invention, and FIG. 2 shows the infrared absorption spectrum of the anion exchange membrane after quaternary amination.

Claims (1)

[Claims] α) At least a portion of the benzene rings of a graft polymer film made of an inert polymer film having α, β, β-trifluorostyrene as a graft chain are substituted with a quaternary aminoalkyl group. Anion exchange membrane. (2) The inert polymer film is a polyethylene film, a polytetrafluoroethylene film, a polychlorotrifluoroethylene film, a polyvinylidene fluoride film, a polyvinyl fluoride film, a tetrafluoroethylene-hexafluoroglopylene copolymer film, Tetrafluoroethylene-ethylene copolymer film, tetrafluoroethylene-propylene copolymer film, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film, chlorotetratrifluoroethylene-ethylene-x polymer film, chlorotrifluoroethylene - An anion exchange membrane according to claim 1, comprising a film selected from the group consisting of: - propylene copolymer film. (3) The anion exchange membrane according to claim (1) or (2), wherein the quaternary aminoalkyl group is a trimethylaminomethyl group. (Xun) An anion exchange membrane formed by substituting at least a part of the benzene ring with a quaternary aminoalkyl group of a graft polymer membrane made of an inert polymer film having α, β, β-trifluorostyrene as a graft chain. During production, an inert polymer film is irradiated with ionizing radiation, the irradiated film is immersed in or brought into contact with α,β,β-trifluorostyrene or a solution thereof to undergo graft polymerization, and then the graft polymerized film is produced. - A method for producing an anion exchange membrane, which comprises performing quaternary amination after loalkylation. (Xun) Inert polymer films include polyethylene film, polytetrafluoroethylene film, polychlorotrifluoroethylene film, polyvinylidene fluoride film, polyvinylene fluoride film, tetrafluoroethylene-hexafluoropropylene co-polymer film, , tetrafluoroethylene-ethylene copolymer film, tetrafluoroethylene-psepyrene copolymer film, nato-2-fluoroethylene-perfluoroalkyl vinyl ether copolymer film, chlorotrifluoroethylene-ethylene The manufacturing method according to claim (4), wherein the film is selected from the group consisting of ethylene-propylene copolymer films. (6) The method of manufacturing the film selected from the group consisting of ethylene-propylene copolymer films. (4) or (5). (7) Any one of claims (4) to (6), wherein the graft polymerization temperature is 10 to 90°C. (8) The manufacturing method according to any one of claims (4) to (7), wherein the graft polymerization time is 1 to 50 hours. (9) α, β, As a solvent for β-trifluorostyrene, chlorotetraform, methylene chloride, carbon tetrachloride, 1.1
．． & 2-tetrachloroethane, 1,1.2-)lichlorotrifluoroethane, and benzene. manufacturing method. aQ The manufacturing method according to any one of claims (4) to (8), wherein α, β, β-trifluorostyrene is graft-polymerized without using a solvent. I. The production method according to any one of claims (4) to 4, wherein the chloromethylating agent is chlormethyA ether. (2) The manufacturing method according to claim 1, wherein the quaternary aminating agent is trimethylamine.