JP5475520B2 - Method for producing anion exchange membrane - Google Patents

Description

  The present invention relates to a method for producing an anion exchange membrane and a polymerizable composition for an anion exchange membrane.

  The ion exchange membrane is a resin-like resin having an ion exchange action and includes a cation exchange membrane into which a cation exchange group is introduced and an anion exchange membrane into which an anion exchange group is introduced. Ion exchange membranes are used in various applications such as electrodialysis, electrolysis, and diffusion dialysis.

  As a method for producing an ion exchange membrane, a polymerizable composition containing a monomer having a functional group suitable for introduction of an ion exchange group, an elastomer, and a crosslinking agent is applied to a base sheet, and the base sheet is used as a release film. A method of laminating and winding with a roller and polymerizing the polymerizable composition on the substrate sheet in a state of being wound around the roller is known. An ion exchange group is introduced into the polymer obtained by polymerizing the polymerizable composition to obtain an ion exchange membrane. As a monomer having a functional group suitable for introduction of the ion exchange group, haloalkylstyrene is widely used (see, for example, Patent Documents 1 and 2).

JP-A-56-36507 JP 2005-146066 A

  However, when haloalkylstyrene is used as a monomer, the obtained polymer and the release film are firmly adhered, and there is a case in which the release film cannot be peeled off successfully from the polymer. In particular, in the production of anion exchange membranes, the amount of haloalkylstyrene used is large, and the frequency of occurrence of the above problems is high.

Patent Document 1 describes that an epoxy compound such as styrene oxide can be used as a supplement for a hydrogen halide generated when haloalkylstyrene is polymerized in the presence of a radical generator.
Patent Document 2 describes that an epoxidized diene block copolymer can be used from the viewpoints of the supplementary effect of hydrogen halide and the chemical stability of the resin itself.
However, Patent Documents 1 and 2 do not describe or suggest any ease of peeling between the polymer and the release film.

  Accordingly, an object of the present invention is to prevent the resin from adhering to the release film side and peeling when releasing the release film and the polymer obtained by polymerizing the polymerizable composition containing haloalkylstyrene. An object of the present invention is to provide a method for producing an anion exchange membrane.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problem of peeling may be caused by the hydrogen halide generated when the haloalkylstyrene is polymerized or the material of the release film. I came to think. As a result of further studies based on the above findings, it was found that the above problem can be solved by including an epoxy compound having two or more glycidyl ether groups in a polymerizable composition containing haloalkylstyrene. It came to complete.

  That is, the method for producing an anion exchange membrane of the present invention comprises a polymerization comprising a haloalkylstyrene, a monomer copolymerizable with haloalkylstyrene, an elastomer, a polymerization initiator, and an epoxy compound having two or more glycidyl ether groups. The adhesive composition is attached to the base sheet, and then a release film is attached to the base sheet, and then a polymerization reaction is performed, and an anion exchange group is introduced into the obtained polymer. It is.

  In the manufacturing method of the anion exchange membrane of this invention, it is preferable that the said release film is a film which consists of polyvinyl alcohol-type resin.

  Further, in the method for producing an anion exchange membrane of the present invention, the content of the epoxy compound having two or more glycidyl ether groups in the polymerizable composition is such that the monomer can be copolymerized with haloalkylstyrene and haloalkylstyrene. It is preferable that it is 1-30 mass parts with respect to a total of 100 mass parts.

  Furthermore, in the method for producing an anion exchange membrane of the present invention, chloromethylstyrene can be suitably used as the haloalkylstyrene.

  Furthermore, in the method for producing an anion exchange membrane of the present invention, the monomer copolymerizable with the haloalkylstyrene is at least one monomer selected from the group consisting of styrene, divinylbenzene and alkyl acrylate ester. It is preferable that

  Moreover, in the manufacturing method of the anion exchange membrane of this invention, it is preferable to introduce | transduce an anion exchange group into the said polymer using an amine compound.

  In the method for producing an anion exchange membrane of the present invention, a compound having 2 to 5 glycidyl ether groups can be suitably used as the epoxy compound.

  The polymerizable composition for an anion exchange membrane of the present invention comprises, after polymerization, a haloalkylstyrene having a functional group capable of introducing an anion exchange group, a monomer copolymerizable with haloalkylstyrene, a polymerization initiator, It contains an elastomer and an epoxy compound having two or more glycidyl ether groups.

  According to the present invention, at the time of releasing a polymer obtained by polymerizing a polymerizable composition containing a haloalkylstyrene and a release film, it is possible to prevent occurrence of resin peeling due to adhesion between the polymer and the release film. An ion exchange membrane production method that can be provided can be provided.

(1) Method for Producing the Anion Exchange Membrane of the Present Invention The method for producing the anion exchange membrane of the present invention comprises a haloalkylstyrene, a monomer copolymerizable with haloalkylstyrene, an elastomer, a polymerization initiator, and a glycidyl ether group. After adhering a polymerizable composition containing two or more epoxy compounds to a base sheet, a release film is attached to the base sheet, and then a polymerization reaction is performed, and an anion is added to the obtained polymer. It is characterized by introducing an exchange group.

  The polymerizable composition in the production method of the present invention contains haloalkylstyrene, a monomer copolymerizable with haloalkylstyrene, an elastomer, a polymerization initiator, and an epoxy compound having two or more glycidyl ether groups. The polymerizable composition of the present invention may further contain other components and additives.

<Monomer>
The haloalkylstyrene in the production method of the present invention is one in which the benzene ring constituting the styrene is substituted with an alkyl halide such as alkyl fluoride, alkyl chloride, alkyl bromide or alkyl iodide. The number of carbon atoms of the halogenated alkyl group is preferably 1 to 5, particularly preferably 1 to 3. Specific examples include chloromethyl styrene, α-chloromethyl styrene, bromomethyl styrene, dichloromethyl styrene, chloroethyl styrene, bromobutyl styrene, and the like. Of these, chloromethylstyrene is preferred. Moreover, the haloalkyl styrene may be one type and may use 2 or more types together.

The monomer copolymerizable with haloalkylstyrene in the production method of the present invention is not particularly limited as long as it is copolymerizable with haloalkylstyrene. Specifically, aromatic compounds substituted with vinyl groups such as styrene, vinyl toluene, chlorostyrene, vinyl naphthalene, divinylbenzene, vinylethylbenzene, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl methacrylate , (Meth) acrylic acid alkyl esters such as dodecyl methacrylate, (meth) acrylic acid derivatives such as acrylic chloride, allyl chloride, vinyl chloride, acrylamide, methyl vinyl ketone, 4-vinyl pyridine, vinyl sulfonyl chloride, styrene sulfonyl chloride Etc. Of the above, styrene, divinylbenzene and alkyl acrylate are preferred. Moreover, the monomer copolymerizable with haloalkylstyrene may be one type, and may use 2 or more types together.
In addition, the polymerizable composition in the production method of the present invention includes, as monomers, haloalkyl styrene and a monomer copolymerizable with haloalkyl styrene as essential components. The body may be contained.
The content of haloalkylstyrene in the whole monomer in the polymerizable composition according to the present invention is preferably 15 to 95% by mass, particularly 45 to 80% by mass from the viewpoint of film characteristics.
Further, the content ratio of the monomer copolymerizable with the haloalkylstyrene in the whole monomer is preferably 5 to 85% by mass, particularly preferably 20 to 55% by mass.

<Elastomer>
The elastomer in the production method of the present invention is blended to give viscosity to the polymerizable composition. A known elastomer can be used, and the elastomer may be a polymer compound that is dispersible with respect to the polymerizable composition or may be a polymer compound that is soluble in the polymerizable composition. Examples of the elastomer include ethylene-propylene copolymer, polybutylene, styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), polyvinyl chloride, polystyrene, and acrylonitrile-butadiene copolymer. Only one type of elastomer may be used, or two or more types may be used in combination.
The content of the elastomer is preferably 5 to 40 parts by mass, and particularly preferably 10 to 30 parts by mass with respect to 100 parts by mass of the total amount of monomers from the viewpoint of film characteristics.

<Polymerization initiator>
It does not specifically limit as a polymerization initiator in the manufacturing method of this invention, A well-known thing can be used. For example, benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, azobisisobutyronitrile, t-butylperoxy-2-ethylhexanoate, 2 , 2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) cyclohexane, 2,2-di (T-butylperoxy) butane, t-butylcumyl peroxide, di-t-hexyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethyl Hexanoate, t-hexyl peroxyisopropyl monocarbonate, t-butyl per Carboxymethyl isopropyl monocarbonate carbonate, t- butyl peroxy-2-ethylhexyl mono-carbonate, 2,5-di (benzoyl peroxy) hexane, and the like. Only one type of polymerization initiator may be used, or two or more types may be used in combination.
The content of the polymerization initiator is preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the total amount of monomers.

<Epoxy compound having two or more glycidyl ether groups>
In the present invention, an epoxy compound having two or more glycidyl ether groups is used. Thereby, the peelability at the time of peeling a release film from a polymer can be improved. Although its mechanism of action is not clear, it is presumed that the above-mentioned epoxy compound is highly compatible with the monomer, is uniformly dispersed, and has an action of capturing hydrogen halide. Is done.
Specific examples of the epoxy compound include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, and polyglycerol polyglycidyl ether. Etc. Only one type of epoxy compound may be used, or two or more types may be used in combination.
As the epoxy compound, an epoxy compound having 2 to 5 glycidyl ether groups is particularly preferable. Moreover, what is water-soluble is preferable.
The molecular weight of the epoxy compound is not particularly limited, but is preferably 100 to 4000 since the compatibility with the monomer may be impaired if the molecular weight is too large.
The content ratio of the epoxy compound is preferably 1 to 30 parts by mass, particularly 3 to 20 parts by mass with respect to 100 parts by mass of the total amount of monomers from the viewpoint of electrochemical properties of the obtained anion exchange membrane. Part.

<Base material sheet>
The base sheet is also referred to as a reinforcing cloth, and is used to impart appropriate strength to the ion exchange membrane and improve durability. As a base material sheet, the base material sheet used in the manufacturing method of a well-known ion exchange membrane can be used. Specific examples include woven fabrics (monofilaments, multifilament mesh cloths), nonwoven fabrics, and porous films made of hydrocarbon resins such as polyolefins such as polyvinyl chloride and polyethylene, and fluorine resins.
In addition, in order to increase the affinity between the substrate sheet and the polymerizable composition, those subjected to surface treatment such as γ-ray, electron beam, ultraviolet irradiation treatment, corona, plasma treatment, etc. can be used. As the base sheet, a sheet made of only one kind of resin may be used, or a sheet made of two or more kinds of resins may be used.

<Release film>
The release film has heat resistance that can withstand the polymerization reaction step of the polymerizable composition, has an appropriate flexibility, and is easily pulled from the polymer attached to the base sheet after the polymerization reaction step. Any material that can be peeled off can be used. Examples of such a release film material include polyvinyl alcohol resins such as vinylon (registered trademark), polyester, polycarbonate, polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), and the like.
A film made of vinyl alcohol resin such as vinylon is preferable from the viewpoint of being inexpensive, flexible and having high uniformity in the film thickness of the resulting polymer. Note that vinyl alcohol resins such as vinylon are more likely to have problems of adhesion with the polymer when used as a release film, and thus can be said to be more effective.
As the release film, a film made of only one kind of resin may be used, or a film made of two or more kinds of resins may be used. Moreover, the film which apply | coated the mold release agent, such as a silicon type and a fluorine type, to the film surface can also be used.

<Polymerization reaction process>
In the manufacturing method of the anion exchange membrane concerning this invention, after making the said polymeric composition adhere to a base material sheet and sticking a release film, polymerization reaction of polymeric composition is performed.
Examples of the method for attaching the polymerizable composition to the base sheet include known methods such as a method by coating such as a comma direct coating method and a gravure coating method, and a method by impregnation such as a dip squeeze processing method. As the polymerization method, radical polymerization is preferred. What is necessary is just to select optimal conditions suitably according to the composition content of a polymeric composition, the kind of polymerization initiator, and the kind of base material sheet. Although superposition | polymerization temperature is based also on the kind of polymerization initiator, Preferably it is 30-180 degreeC, More preferably, it is 50-120 degreeC. As a method for raising the temperature, a method of polymerizing by raising the temperature to a predetermined temperature for a certain time, for example, 0.1 to 48 hours, or a multistage temperature polymerization method in which several polymerization temperatures are set and the temperature rise and temperature holding are repeated step by step. Etc. Examples of the heating method for increasing the temperature include a method of immersing and heating in a hot water tank, and a method of heating using an air thermostat.
Examples of the method for industrially producing an anion exchange membrane include the following methods. Each of the base sheet and the release sheet to which the polymerizable composition is attached is sent out by a roller, and the release sheet is attached to one surface of the base sheet. A method of performing a polymerization reaction step of a polymerizable composition by winding a sheet on which both are bonded with a roller and immersing the roller in warm water.

<Ion exchange group introduction process>
After the polymerization reaction step, an anion exchange group is introduced into the obtained polymer. The method for introducing an anion exchange group is not particularly limited, and a known method can be employed. For example, there is a method of treating the obtained polymer with an amine compound to quaternize the haloalkyl group in the haloalkylstyrene copolymer. As the amine compound, for example, trimethylamine, dimethylethanolamine, methyldiethanolamine, triethylamine and the like can be suitably used.
The release film is preferably peeled off from the base sheet before the anion exchange group introduction step.
As a preferable embodiment of the method for introducing the anion exchange group, for example, the release film is peeled off from the base material sheet to which the polymer is adhered, and then the base material sheet is immersed in a methanol solution of trimethylamine. A method of reacting at a temperature of 1 ° C. for one day and then quaternizing ammonium chloride of the haloalkyl group in the polymer can be mentioned. In addition, when the polymerization reaction is performed by winding the substrate sheet into a roller shape as described above, it is preferable to immerse the roller-shaped substrate sheet in a solution containing an amine compound.

(2) Polymerizable composition for anion exchange membrane of the present invention The polymerizable composition for anion exchange membrane of the present invention comprises a haloalkylstyrene having a functional group capable of introducing an anion exchange group after polymerization, and a haloalkylstyrene. And a monomer capable of copolymerization, a polymerization initiator, an elastomer, and an epoxy compound having two or more glycidyl ether groups.
Regarding the compounding ratio of haloalkyl styrene, a monomer copolymerizable with haloalkyl styrene, a polymerization initiator, an elastomer, and an epoxy compound having two or more glycidyl ether groups, and each component, (1) Anion of the present invention This is the same as described in the method for manufacturing the exchange membrane. An anion exchange membrane is obtained by polymerizing the polymerizable composition for an anion exchange membrane, preferably by thermal polymerization, and introducing an anion exchange group into the obtained polymer.
The viscosity of the polymerizable composition of the present invention is preferably 200 to 5000 mPa · S, more preferably 800 to 3000 mPa · S at 25 ° C. from the viewpoint of adhesion to a substrate and film properties. The viscosity can be adjusted by the type and concentration of the elastomer.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these Examples and comparative examples.

Example 1
60 parts by mass of chloromethylstyrene, 10 parts by mass of styrene, 30 parts by mass of industrial divinylbenzene, 1.8 parts by mass of t-butylperoxy-2-ethylhexanoate (Nippon Yushi Co., Ltd., Perbutyl O), heat as an elastomer A polymerizable composition was obtained in which 30 parts by mass of Hibler 5125 (manufactured by Kuraray Co., Ltd.), which is a plastic elastomer, and 6 parts by mass of sorbitol polyglycidyl ether as an epoxy compound were blended. Denacol EX-614B (manufactured by Nagase ChemteX Corporation) was used as sorbitol polyglycidyl ether.

  The obtained polymerizable composition was adhered to a polyethylene woven fabric (base material sheet) by a dip squeeze processing method. Thereafter, a vinylon film (release film) is attached to both sides of the base sheet and coated, and then immersed in a hot water tank and heated for 2 hours at 35 ° C., 6 hours at 70 ° C., 8 at 90 ° C. The polymerization reaction was carried out by heating stepwise for a time. Thereafter, the release film was peeled off from the base sheet by hand, and the appearance and the peeled state of the release film were evaluated according to the following criteria for the obtained polymer. The results are shown in Table 1 below.

(appearance)
The appearance of the obtained polymer was visually evaluated for the occurrence of white spots.

(Evaluation criteria for release film peeling state)
(Double-circle): When peeling a film and a release film, it peels without resistance and the malfunction of resin peeling on the film surface is not seen.
○: When the film and the release film are peeled off, although there is a little resistance, it is easily peeled off, and there is no defect such as resin peeling on the film surface.
Δ: The film and the release film can be peeled off, but the resin adheres to the release film side and the surface property of the film is poor. However, it does not happen until the membrane is broken.
X: Although the film and the release film can be peeled off, the resin adheres to the release film side and the film is torn.
XX: The film and the release film are integrated and cannot be peeled off.

  Next, the obtained polymer was immersed in a methanol solution of 1.2 (mol / L) trimethylamine and reacted at a temperature of 45 ° C. for 16 hours to obtain a quaternary ammonium base type anion exchange membrane. . The ion exchange membrane characteristics (static transport number, effective resistance) of the obtained anion exchange membrane were evaluated. The static transport number was calculated from the grayscale potential of 25 ° C., 0.5 mol / L-saline solution and 1.0 mol / L-saline solution. The effective resistance is an AC resistance value at 25 ° C. and 0.5 mol / L-saline solution. The obtained results are shown in Table 1 below.

(Example 2)
Heavy weight obtained in the same manner as in Example 1 except that 6 parts by mass of propylene glycol diglycidyl ether (Denacol EX-911 manufactured by Nagase ChemteX Corporation) was used in place of the epoxy compound used in Example 1. The coalescence was evaluated for the state of peeling from the release film and the ion exchange membrane characteristics of the obtained anion exchange membrane. The results are shown in Table 1 below.

(Comparative Example 1)
Except that no epoxy compound was used, the polymer obtained in the same manner as in Example 1 was evaluated for the state of peeling from the release film. The results are shown in Table 1 below.

(Comparative Example 2)
The polymer obtained in the same manner as in Example 1 except that allyl glycidyl ether (Denacol EX-111 manufactured by Nagase ChemteX Corporation) was used instead of the epoxy compound of Example 1 was peeled off from the release film. The state was evaluated. The results are shown in Table 1 below. In Comparative Examples 1 and 2, production and evaluation of ion exchange membranes by introducing anion exchange groups were not performed.

※１：パーブチルＯ（日本油脂株式会社製）
※２：ハイブラー５１２５（株式会社クラレ製）
※３：デナコールＥＸ−６１４Ｂ（ナガセケムテックス株式会社製）
※４：デナコールＥＸ−９１１（ナガセケムテックス株式会社製）
※５：デナコールＥＸ−１１１（ナガセケムテックス株式会社製）

* 1: Perbutyl O (Nippon Yushi Co., Ltd.)
* 2: Hibler 5125 (manufactured by Kuraray Co., Ltd.)
* 3: Denacol EX-614B (manufactured by Nagase ChemteX Corporation)
* 4: Denacol EX-911 (manufactured by Nagase ChemteX Corporation)
* 5: Denacol EX-111 (manufactured by Nagase ChemteX Corporation)

In the said Example 1 and 2 using the epoxy compound which has a 2 or more glycidyl ether group, the white spot was not seen by the obtained polymer. Further, the polymer could be easily peeled off from the release film. Furthermore, the characteristics of the obtained anion exchange membrane were not different from general ones, and no inconvenience was found due to the incorporation of the epoxy compound.
On the other hand, in Comparative Example 1 in which no epoxy compound was used, white spots were observed on the film, and the polymer could not be peeled from the release film. In Comparative Example 2 using an epoxy compound having only one glycidyl ether group, no white point was observed, but the polymer could not be peeled from the release film.

Claims (8)

  After attaching a polymerizable composition containing haloalkyl styrene, a monomer copolymerizable with haloalkyl styrene, an elastomer, a polymerization initiator, and an epoxy compound having two or more glycidyl ether groups to the base sheet, A method for producing an anion exchange membrane, comprising a step of attaching a release film to a substrate sheet, then performing a polymerization reaction, and introducing an anion exchange group into the obtained polymer.   The method for producing an anion exchange membrane according to claim 1, wherein the release film is a film made of a polyvinyl alcohol resin.   The content ratio of the epoxy compound having two or more glycidyl ether groups in the polymerizable composition is 1 to 30 parts by mass with respect to 100 parts by mass in total of monomers copolymerizable with haloalkylstyrene and haloalkylstyrene. A method for producing an anion exchange membrane according to claim 1 or 2.   The method for producing an anion exchange membrane according to any one of claims 1 to 3, wherein the haloalkylstyrene is chloromethylstyrene.   The anion according to any one of claims 1 to 4, wherein the monomer copolymerizable with the haloalkylstyrene is at least one monomer selected from the group consisting of styrene, divinylbenzene, and alkyl acrylate. An exchange membrane manufacturing method.   The method for producing an anion exchange membrane according to any one of claims 1 to 5, wherein an anion exchange group is introduced into the polymer using an amine compound.   The method for producing an anion exchange membrane according to any one of claims 1 to 6, wherein the epoxy compound is a compound having 2 to 5 glycidyl ether groups.   After polymerization, a haloalkylstyrene having a functional group capable of introducing an anion exchange group, a monomer copolymerizable with haloalkylstyrene, a polymerization initiator, an elastomer, and an epoxy compound having two or more glycidyl ether groups A polymerizable composition for an anion exchange membrane, comprising: