JP2000080120A - Preparation of polymer material, preparation of solid polymer electrolyte membrane, and solid polymer electrolyte type of fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sulfonic acid group-contg. polymer material, a solid polymer electrolyte membrane and a solid polymer electrolyte type fuel cell, each at low costs. SOLUTION: A preparative process for a polymer material comprises, in a synthetic stage for a polymer material having a sulfonic acid group, introducing a -SO2X group (wherein X is F or Cl) onto the polymer material, then converting the said -SO2X (wherein X is F or Cl) into a sulfonic acid group by hydrolytic treatment. And, a preparative process for a solid polymer electrolyte membrane comprises, in a synthetic stage for a solid polymer electrolyte membrane having a sulfonic acid group, introducing a -SO2X group (wherein X is F or Cl) onto a solid polymer membrane, then converting the -SO2X group (wherein X is F or Cl) into a sulfonic acid group by hydrolytic treatment. And besides, a solid polymer electrolyte type of fuel cell uses the solid polymer electrolyte membrane as an electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polymer material, a method for producing a solid polymer electrolyte membrane, and a solid polymer electrolyte fuel cell.

[0002]

2. Description of the Related Art A fuel cell generally has a large number of cells stacked, and the cell has two electrodes (a fuel electrode and an air electrode).
Has a structure sandwiching the electrolyte.

At the fuel electrode, the following reaction occurs when hydrogen gas comes into contact with the catalyst.

[0004] 2H ₂ → 4H ⁺ + 4e ⁻ H ⁺ moves through the electrolyte, reaches the air electrode catalyst, reacts with oxygen in the air to become water.

4H ⁺ + 4e ⁻ + O ₂ → 2H ₂ O By the above-described reaction, hydrogen and oxygen are used to generate power by a reverse reaction of electrolysis, and attention is paid to a clean power generation device that has no emissions other than water.

[0006] In order to reduce air pollution as much as possible, it is important to take measures against exhaust gas from automobiles. As one of the measures, electric vehicles are used. However, due to problems such as charging facilities and mileage, they have become widespread. Not in. Vehicles using fuel cells are seen as the most promising clean vehicles.

[0007] Among the above fuel cells, solid polymer electrolyte fuel cells are most promising for automobiles because they operate at low temperatures. The electrolyte of the solid polymer electrolyte fuel cell is a solid polymer electrolyte membrane.

The performance required for the solid polymer electrolyte membrane is as follows:
This is to flow more H ⁺ , and sulfonic acid groups having an ion exchange function are introduced into the solid polymer membrane.

One of the obstacles to the widespread use of the fuel cell is that the cost is high.
It is important to reduce the cost of a solid polymer electrolyte membrane, which is a main component of a fuel cell, as much as possible.

The solid polymer electrolyte membrane can be used not only for the solid polymer electrolyte fuel cell but also for a salt electrolyte membrane for producing sodium hydroxide, hydrogen and chlorine from seawater. The salt electrolyte membrane is already used in large quantities.

Further, as a polymer material having a sulfonic acid group other than the solid polymer electrolyte membrane, it is used as a cation exchange resin in water treatment such as waste water treatment and the like, and as a highly water-absorbent resin in paper diapers and the like.

As described above, the polymer material having a sulfonic acid group and the solid polymer electrolyte membrane have a wide range of applications, and it is important to reduce the cost.

As prior art 1, "Experimental method for polymer science"
(Publisher: Tokyo Chemical Co., Ltd., Publication date: 1983
July 1 (1st edition, 2nd printing), pp. 71-72), HSO ₃ Cl was reacted with polystyrene to obtain —SO ₂
After introducing a Cl group, the mixture is treated with sodium hydroxide to give -SO
_A method for producing a cation exchange resin in which a sulfonic acid group is introduced by reacting with sulfuric acid after converting into a 3Na group is disclosed.

That is, in order to produce polystyrene sulfonic acid from polystyrene, the polystyrene is subjected to a sulfonyl chloride reaction using HSO ₃ Cl to introduce a —SO ₂ Cl group as shown in the chemical formula (1). It is reacted with sodium hydroxide _-SO 3 the _-SO 2 Cl group Na
Changed based on sodium ions the -SO ₃ Na groups is exchanged for hydrogen ion cation exchange resin H-shaped are converted to sulfonic acid groups are obtained when further treated with sulfuric acid.

[0015]

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As prior art 2, Japanese Patent Application Laid-Open No. 9-102
No. 322 discloses that a copolymer of a fluorocarbon vinyl monomer having an alkylbenzene group and a hydrocarbon vinyl monomer is reacted with HSO ₃ Cl to introduce a —SO ₂ Cl group, followed by treatment with potassium hydroxide. A method for producing a solid polymer electrolyte membrane in which a —SO ₃ K group is formed and then reacted with sulfuric acid to introduce a sulfonic acid group is disclosed.

[0017]

However, the prior art 1 requires three reaction steps of a reaction with HSO ₃ Cl, a reaction with sodium hydroxide, and a reaction with sulfuric acid. _Three reaction steps are required: a reaction with ₃ Cl, a reaction with potassium hydroxide, and a reaction with sulfuric acid. All of these require three reaction steps to introduce a sulfonic acid group. It is necessary to raise the temperature to increase the reactivity. Since the number of steps is large, the cost of the reaction material and the number of man-hours are large, the reaction apparatus is required for each, and the cost of treating the waste liquid is large.

The present invention has solved the above-mentioned problems, and provides a polymer material having a sulfonic acid group, a method for manufacturing a solid polymer electrolyte membrane, and a solid polymer electrolyte fuel cell which are low in manufacturing cost.

[0019]

Means for Solving the Problems In order to solve the above technical problems, the technical means (hereinafter referred to as the first technical means) taken in claim 1 of the present invention comprises a sulfonic acid group. in the process of synthesizing polymeric material having, after (the X F or Cl) _-SO 2 X in the polymer stock was introduced groups, the hydrolyzing treatment with water _-SO 2 X (X is F or Cl And b) converting the group into a sulfonic acid group.

The effects of the first technical means are as follows.

That is, since only one hydrolysis step is required to convert a —SO ₂ X (X is F or Cl) group into a sulfonic acid group, only water is required for the reaction and the chemical reaction required for the reaction is required. Substances and man-hours can be largely saved, the number of reaction devices can be reduced, and the amount of waste liquid to be discharged can be reduced by only HCl, so that the production cost of the polymer material having a sulfonic acid group can be reduced.

In order to solve the above technical problems, the technical means (hereinafter referred to as the second technical means) taken in claim 2 of the present invention is a solid polymer electrolyte membrane having a sulfonic acid group. In the synthesis process, after producing a solid polymer membrane having a —SO ₂ X (X is F or Cl) group, the solid polymer film is subjected to hydrolysis treatment with water to perform the —SO ₂ X (X is F or Cl) group. To a sulfonic acid group.

The effects of the second technical means are as follows.

That is, since only one hydrolysis step is required to convert the —SO ₂ X (X is F or Cl) group to the sulfonic acid group, only water is required for the reaction, and the chemical reaction required for the reaction is required. Substances and man-hours can be greatly saved, the number of reactors can be reduced, and the amount of waste liquid to be discharged can be reduced by only HCl, so that the production cost of the solid polymer electrolyte membrane can be reduced.

In order to solve the above technical problem, the technical means (hereinafter referred to as a third technical means) taken in claim 3 of the present invention is the above-mentioned -SO ₂ X (X is F or _3. The solid polymer electrolyte according to claim 2, wherein the method for producing a solid polymer film having a Cl) group is a method of reacting HSO ₃ X (X is F or Cl) with the solid polymer film. This is a method for producing a film.

The effects of the third technical means are as follows.

That is, there is an effect that a solid electrolyte membrane can be easily manufactured using an existing solid polymer membrane.

In order to solve the above technical problem, the technical means (hereinafter referred to as fourth technical means) taken in claim 4 of the present invention is the above-mentioned -SO ₂ X (X is F or method of making a solid polymer membrane having a Cl) group, -SO 2 X in the monomer or oligomer _(X is according to claim 2, characterized in that the method for polymerizing after introducing F or Cl) group This is a method for producing a solid polymer electrolyte membrane.

The effects of the fourth technical means are as follows.

That is, -SO ₂ X (X is F
Or the introduction of a —SO ₂ X (X is F or Cl) group into a monomer or an oligomer rather than the introduction of a Cl) group, because the reaction efficiency is higher, and the reaction can be performed at a low temperature in a short time, so that the production cost is reduced. In addition, there is an effect that various kinds of solid polymer electrolyte membranes can be manufactured by selecting a monomer or an oligomer.

In order to solve the above technical problem, a technical measure taken in claim 5 of the present invention (hereinafter referred to as a fifth technical measure) is that the solid polymer film has an alkylbenzene group. 3. The method for producing a solid polymer electrolyte membrane according to claim 2, wherein the method is a copolymer of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer.

The effects of the fifth technical means are as follows.

That is, since a solid polymer electrolyte membrane can be manufactured using an inexpensive solid polymer electrolyte membrane, there is an effect that a further inexpensive solid polymer electrolyte membrane can be manufactured.

In order to solve the above technical problem, the technical measures taken in claim 6 of the present invention (hereinafter, referred to as sixth technical means) are -SO ₂ X (X is F or C).
After preparing the solid polymer membrane having a l) group, is the -SO 2 X _(X and hydrolysis with water solid high having a sulfonic acid group obtained by converting the F or Cl) groups to sulfonic acid groups This is a solid polymer electrolyte fuel cell in which an assembly of a polymer electrolyte membrane and an electrode having a catalyst is sandwiched between separators.

The effects of the sixth technical means are as follows.

That is, since an inexpensive solid polymer electrolyte membrane is used as the electrolyte, a low-cost solid polymer electrolyte fuel cell can be obtained.

[0037]

Embodiments of the present invention will be described below.

In the reaction process of introducing a sulfonic acid group in the present invention, for example, in order to synthesize the polystyrene sulfonic acid by introducing the sulfonic acid group into polystyrene, HSO is added to the polystyrene as shown in the chemical formula (2).
₃ by addition of Cl -SO by sulfonyl chloride reaction
After the introduction of ₂ Cl groups, it is reacted with water to form the -SO ₂ C
This is done by changing the 1 group to a sulfonic acid group.

[0039]

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Polystyrene is mentioned as an example of the polymer for introducing a sulfonic acid group.
B resin, AS resin, AES resin, styrene-divinylbenzene copolymer, polycarbonate, polyethylene terephthalate, polyarylate, aromatic polysulfone, aromatic polyethersulfone, polyphenylene sulfide, aromatic polyamideimide, aromatic polyamide, aromatic polyimide And polymers having an aromatic ring such as aromatic polyether, aromatic polyether ketone, aromatic polyether ether ketone, and polybenzimidazole, and polymers such as polyethylene, polypropylene, polyacetal, nylon 6, acrylic resin and methacrylic resin. Copolymers and monomers or oligomers that are the starting materials for these polymers are included.

Further, a copolymer of a fluorocarbon vinyl monomer having an alkylbenzene group and a hydrocarbon vinyl monomer may be used. The sulfonic acid group-introduced copolymer is particularly important as an inexpensive solid polymer electrolyte membrane. Examples of the copolymer of the fluorocarbon vinyl monomer and the hydrocarbon vinyl monomer include an ethylene-tetrafluoroethylene copolymer.

Using HSO ₃ Cl as a sulfonating agent,
The reaction conditions for introducing the -SO ₂ Cl group into the above-mentioned polymer include, without solvent, or in the presence of a solvent, preferably 1,
1,2,2-tetrachloroethane, 1,1,1,2-tetrachloroethane, 1,1,1-trichloroethane,
The reaction is carried out with 1,2-dichloroethane, trichloroethylene, tetrachloroethylene, chloroform or the like.

The solvent causes the polymer to swell and the H
There is no particular limitation as long as it does not react with SO ₃ Cl.
The concentration of the HSO ₃ Cl is not particularly limited with respect to the solvent or the polymer, but is preferably HSO ₃ Cl / solvent = 1/1 to 1/500 (volume ratio), HSO ₃ Cl /
Polymer = 2/1 to 100/1 (molar ratio). In addition,
The number of moles of the polymer referred to herein is the number of moles of the repeating unit, and when the repeating unit of the polymer has a plurality of aromatic rings into which a sulfone group can be introduced, the number of moles of the polymer is the same as that of the polymer. It is the number times the number of aromatic rings in the repeating unit of merging.

The reaction temperature and reaction time are not particularly limited,
Preferably it is 0-100 degreeC, Preferably it is 0.5-100 hours.

The conditions for the hydrolysis treatment for converting the -SO ₂ Cl group into a sulfonic acid group are not particularly limited with respect to the reaction temperature and the reaction time, but are preferably 20 to 100 ° C, preferably 0.1 to 100 ° C.
5 to 100 hours.

Example: An ethylene-tetrafluoroethylene copolymer film (50 μm thick) which is a copolymer of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer
After irradiating γ-rays at a dose of 10 kGy in nitrogen at room temperature, the film was immersed in a styrene / divinylbenzene / xylene = 97/3/30 (volume) mixture at 60 ° C. for 2 hours to obtain ethylene. -A crosslinked styrene chain was grafted to the ethylene tetrafluoride copolymer to produce an ethylene-tetrafluoroethylene copolymer film having a grafted styrene side chain as an alkylbenzene group.

After drying the film, the film is immersed in a mixture of 5 parts by volume of HSO ₃ Cl and 100 parts by volume of 1,2-dichloroethane at room temperature for 1 hour to form a —SO ₂ Cl group on the benzene ring of the side chain of the grafted styrene. Introduced. -S
After drying the film into which the O ₂ Cl group was introduced, the film was immersed in ion-exchanged water at 90 ° C. for 1 hour, and further washed with fresh ion-exchanged water at 90 ° C. for 2 hours.

The solid polymer electrolyte membrane thus obtained had an ion exchange capacity of 1.66 meq / g and a water content at 80 ° C. of 73% by weight.

A commercially available carbon paper (TG, manufactured by Toray Industries, Inc.)
PH-060) was prepared by diluting a tetrafluoroethylene particle dispersion (D-1 grade, manufactured by Daikin Industries, containing 60% by weight of tetrafluoroethylene particles) with water so that the tetrafluoroethylene particle concentration became 15% by weight. After immersion in the fluoroethylene particle dilution solution for 2 minutes,
The water was evaporated at about 80 ° C. and kept at 390 ° C. in the air for 60 minutes to perform a water-repellent treatment.

Pt-supported carbon (platinum content 40 wt.
%), Water, an ion exchange solution (Aciplex solution SS-1080, manufactured by Asahi Kasei Corporation) and isopropyl alcohol are sufficiently mixed to prepare a catalyst paste, and the amount of platinum becomes approximately 0.35 mg / cm ² by a doctor blade method. And dried to produce a gas diffusion electrode.

A solid polymer electrolyte membrane was joined by hot pressing using the gas diffusion electrode as a positive electrode and a negative electrode to form a fuel cell. Hydrogen pressure 2.5 atm (80% utilization),
Air pressure 2.5 atm (utilization rate 40%), battery temperature 80 ° C
, The VI characteristics were measured. As a result, the current density 1
The output voltage was 0.52 V at A / cm ² .

COMPARATIVE EXAMPLE In the same manner as in the Example, a film of an ethylene-tetrafluoroethylene copolymer having a grafted styrene side chain was obtained by introducing a —SO ₂ Cl group into the benzene ring of the grafted styrene side chain. 90 ° C, dried film
Hydrolysis in 1N potassium hydroxide for 1 hour, followed by 90 hours
The solution was immersed in 1N hydrochloric acid at 1 ° C. for 1 hour to replace the potassium ion of the sulfonic acid group with a hydrogen ion to introduce a sulfonic acid group.
Next, the substrate was washed in ion-exchanged water at 90 ° C. for 2 hours.

The ion exchange capacity of the obtained solid polymer electrolyte membrane was 1.71 meq / g, and the water content at 80 ° C. was 78.
% By weight.

A fuel cell was formed with the same gas diffusion electrode as in the example, and VI characteristics were measured under the same conditions as in the example. As a result, the output voltage was 0.51 V at a current density of 1 A / cm ² .

As a result, the ion exchange capacity and the water content of the solid polymer electrolyte membrane manufactured by the manufacturing method of the embodiment, which is the manufacturing method of the present invention, are the same as those of the solid polymer electrolyte membrane manufactured by the conventional manufacturing method. The values were the same as those of the electrolyte membrane, and the cell characteristics of the fuel cell using the solid polymer electrolyte membrane of the example were equivalent to those of the fuel cell using the solid polymer electrolyte membrane of the comparative example.

Therefore, it was confirmed that the -SO ₂ Cl group was sufficiently converted to the sulfonic acid group by the production method of the present invention. The use of the production method of the present invention eliminates the need for the reaction step of caustic potash and the reaction step of hydrochloric acid as in the comparative example. There is no need to treat the waste liquid discharged from the fuel cell, and the manufacturing cost of the solid polymer electrolyte membrane can be reduced.

[0057]

As described above, according to the present invention, in the process of synthesizing a polymer material having a sulfonic acid group, water is introduced into a polymer raw material after introducing a —SO ₂ X (X is F or Cl) group. used hydrolysis treatment to the -SO 2 X _(X is F or Cl) based on the solid polymer electrolyte membrane having a manufacturing method and a sulfonic acid group of a polymer material, characterized by converting to sulfonic acid groups In the synthesis process, -SO ₂ X (X is F
Or Cl) After preparing the solid polymer membrane having a group, is the -SO 2 X _(X and hydrolysis with water F or C
l) a method for producing a solid polymer electrolyte membrane, which comprises converting a group into a sulfonic acid group, and a solid polymer electrolyte fuel cell using the solid polymer electrolyte membrane as an electrolyte; Eliminates the need for sulfuric acid or hydrochloric acid and replaces cheaper and safer water, thereby lowering the cost of reacting materials and treating waste liquids, and reducing the number of reactors and man-hours, resulting in lower manufacturing costs and lower costs. Can be.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01M 8/02 H01M 8/02 P 8/10 8/10

Claims (6)

[Claims] In a process of synthesizing a polymer material having a sulfonic acid group, after introducing a —SO ₂ X (X is F or Cl) group into a polymer material, the polymer is subjected to a hydrolysis treatment with water to form the polymer material. A method for producing a polymer material, comprising converting an SO ₂ X (X is F or Cl) group into a sulfonic acid group. 2. In a process of synthesizing a solid polymer electrolyte membrane having a sulfonic acid group, -SO ₂ X (X is F or C
After preparing the solid polymer membrane having a l) group, is the -SO 2 X _(X and hydrolysis with water the solid height and converting the F or Cl) groups to sulfonic acid groups A method for producing a molecular electrolyte membrane. 3. The method for producing a solid polymer membrane having a —SO ₂ X (X is F or Cl) group according to claim 1, wherein the solid polymer membrane is reacted with HSO ₃ X (X is F or Cl). 3. The method for producing a solid polymer electrolyte membrane according to claim 2, wherein: 4. The method for producing a solid polymer membrane having a —SO ₂ X (X is F or Cl) group according to claim 1, wherein the method includes the step of introducing a —SO ₂ X (X is F or Cl) group into a monomer or an oligomer. The method for producing a solid polymer electrolyte membrane according to claim 2, wherein the method is a polymerization method. 5. The production of a solid polymer electrolyte membrane according to claim 2, wherein said solid polymer membrane is a copolymer of a fluorocarbon vinyl monomer having an alkylbenzene group and a hydrocarbon vinyl monomer. Method. 6. After producing a solid polymer membrane having a —SO ₂ X (X is F or Cl) group, the solid polymer membrane is subjected to a hydrolysis treatment using water to carry out the —SO ₂ X (X is F or Cl) group. A solid polymer electrolyte fuel cell in which a joined body of a solid polymer electrolyte membrane having a sulfonic acid group in which is converted to a sulfonic acid group and an electrode having a catalyst is sandwiched between separators.