Polymer electrolyte material, polymer electrolyte molded body using the same, electrolyte membrane with catalyst layer, membrane electrode assembly, solid polymer fuel cell, and water electrolysis hydrogen generation device

Abstract

A polymer electrolyte material composed of a block copolymer having a segment containing an ionic group (hereinafter referred to as "ionic segment") and a segment not containing an ionic group (hereinafter referred to as "non-ionic segment"), respectively, has a phase separation structure, and satisfies at least one of the following Condition 1 and Condition 2. <Condition 1> The saturation crystallinity of the polymer electrolyte material determined by wide-angle X-ray diffraction is 5% or more and 30% or less, <Condition 2> the ion exchange capacity (IEC) of the polymer electrolyte material is 1.8 meq / g or more and 3.0 meq / g or less, and the product of the IEC (meq / g) of the polymer electrolyte material and the heat of crystallization (J / g) of the polymer electrolyte material determined by differential scanning calorimetry is 35.0 or more and 47.0 or less. A polymer electrolyte material having good mechanical durability and excellent proton conductivity is provided.

Description

Technical Field

[0001] This invention relates to polymeric electrolyte materials, polymeric electrolyte molded bodies using the same, electrolyte membranes with catalyst layers, membrane electrode assemblies, solid polymeric fuel cells, and water electrolysis hydrogen generators. Background Technology

[0002] Fuel cells are power generation devices that extract electrical energy by electrochemically oxidizing fuels such as hydrogen and methanol. In recent years, they have attracted attention as a clean energy source. Solid polymer fuel cells, in particular, have a low standard operating temperature of around 100°C and high energy density, making them promising for widespread application in smaller-scale distributed power generation facilities, as well as power generation devices in vehicles, ships, and other mobile devices. Furthermore, solid polymer fuel cells are also attracting attention as a power source for small mobile and portable devices, and are expected to replace secondary batteries such as nickel-metal hydride and lithium-ion batteries in mobile phones and personal computers.

[0003] Fuel cells are typically constructed using a membrane electrode assembly (MEA) sandwiched between two layers of an electrolyte membrane. An MEA consists of catalyst layers on both sides of an electrolyte membrane, with gas diffusion layers further positioned on either side. In the MEA, the catalyst layers and gas diffusion layers sandwiching the electrolyte membrane form a pair of electrode layers, one serving as the anode and the other as the cathode. Electricity is generated through an electrochemical reaction by contacting the anode with a hydrogen-containing fuel gas and the cathode with air. The electrolyte membrane is primarily composed of a polymeric electrolyte material. This polymeric electrolyte material can also be used as a binder in the catalyst layers.

[0004] Previously, fluorine-based polymeric electrolytes, such as Nafion (registered trademark) manufactured by Kemaz Co., Ltd., were widely used. However, the development of inexpensive hydrocarbon-based electrolytes that can replace Nafion (registered trademark) and offer superior membrane properties has become increasingly active in recent years. Hydrocarbon-based electrolytes exhibit excellent low gas permeability and heat resistance, and research has been particularly active on electrolytes using aromatic polyetherketones and aromatic polyethersulfones. However, while conventional hydrocarbon-based electrolytes have shown proton conductivity equal to or better than fluorine-based electrolytes under high humidification conditions, their proton conductivity is insufficient.

[0005] To address the aforementioned issues, a hydrocarbon-based polymer electrolyte membrane with a phase separation structure has been proposed as an example of a membrane that improves proton conductivity and mechanical durability (see, for example, Patent Documents 1 and 2).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2008 / 018487

[0009] Patent Document 2: International Publication No. 2013 / 031675 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] It can be expected that the proton conductivity and mechanical durability of the polymer electrolyte membranes disclosed in the aforementioned patent documents will be improved.

[0012] However, proton conductivity and mechanical durability are usually mutually restrictive, that is, if proton conductivity is increased, mechanical durability decreases, and vice versa. Even if the electrolyte membrane described in Patent Documents 1-2 is used, there is still a problem that it is difficult to achieve these properties at a high level at the same time.

[0013] Therefore, in view of the background of the prior art described above, the present invention aims to provide a polymeric electrolyte material that simultaneously achieves high levels of proton conductivity and mechanical durability.

[0014] Methods for solving problems

[0015] The polymeric electrolyte material of the present invention adopts the following structure to solve the above-mentioned problems. That is,

[0016] A polymeric electrolyte material is composed of block copolymers, wherein the block copolymers have segments containing ionic groups and segments not containing ionic groups, the polymeric electrolyte material has a phase-separated structure, and satisfies at least one of the following conditions 1 and 2.

[0017] <Condition 1> The saturated crystallinity of the polymeric electrolyte material, as determined by wide-angle X-ray diffraction, is 5% or more and 30% or less.

[0018] <Condition 2> The ion exchange capacity (IEC) of the polymer electrolyte material is 1.8 meq / g or more and 3.0 meq / g or less, and the product of the IEC (meq / g) of the polymer electrolyte material and the heat of crystallization (J / g) of the polymer electrolyte material determined by differential scanning calorimetry is 35.0 or more and 47.0 or less.

[0019] The polymeric electrolyte molded body of the present invention adopts the following structure to solve the above-mentioned problems. That is,

[0020] It is a polymeric electrolyte molded body containing the aforementioned polymeric electrolyte material.

[0021] The electrolyte membrane with a catalyst layer of the present invention is configured to solve the above-mentioned problems in the following way. That is,

[0022] It is an electrolyte membrane with a catalyst layer, which is constructed using the above-mentioned polymer electrolyte molded body.

[0023] The membrane electrode assembly of the present invention is configured to solve the above-mentioned problems. That is, it is a membrane electrode assembly constructed using the above-mentioned polymer electrolyte molded body.

[0024] The solid polymer fuel cell of the present invention is configured to solve the above-mentioned problems. Specifically, it is a solid polymer fuel cell constructed using the aforementioned polymer electrolyte molded body.

[0025] For the polymeric electrolyte material of the present invention, it is preferred that the polymeric electrolyte material has a co-continuous phase separation structure or a layered phase separation structure.

[0026] For the polymeric electrolyte material of the present invention, it is preferred that the average period size of the phase separation structure is 15 to 100 nm.

[0027] For the polymeric electrolyte material of the present invention, it is preferred that the block copolymer is an aromatic polyether copolymer.

[0028] For the polymeric electrolyte material of the present invention, it is preferred that the block copolymer is an aromatic polyether ketone copolymer.

[0029] For the polymeric electrolyte material of the present invention, it is preferred that the block copolymer has a connecting portion that binds the ionic segments and the nonionic segments.

[0030] For the polymeric electrolyte material of the present invention, it is preferred that the nonionic segments contain a structure represented by the following general formula (S3).

[0031] *-Ar 5 -Y 3 -Ar 6 -O-Ar 7 Y 4 -Ar 8 -O-* (S3)

[0032] (In general formula (S3), Ar) 5 ~Ar 8 Each can be used independently to represent either a substituted arylene or an unsubstituted arylene. Where Ar... 5 ~Ar8 Neither of them possesses ionic groups. 3 and Y 4 Each group independently represents a ketone group and a protecting group capable of being derived into a ketone group. * indicates a bond with a unit of general formula (S3) or other structural units.

[0033] For the polymeric electrolyte material of the present invention, it is preferred that the structure represented by the general formula (S3) is the structure represented by the following general formula (S4).

[0034]

[0035] (In general formula (S4), Y) 3 and Y 4 Each protector group represents a ketone group or a protecting group that can be derived into a ketone group independently. * indicates a bond with the general formula (S4) or other structural units.

[0036] For the polymeric electrolyte material of the present invention, it is preferred that the number-average molecular weight of the nonionic segments is 15,000 or more.

[0037] Invention Effects

[0038] According to the present invention, a polymeric electrolyte material that simultaneously achieves high levels of proton conductivity and mechanical durability can be provided. Attached Figure Description

[0039] [ Figure 1 ] Figure 1 This is a schematic diagram of the phase separation structure in a polymer electrolyte material. Detailed Implementation

[0040] The embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be implemented in various ways according to the purpose and use.

[0041] The polymeric electrolyte material of the present invention is composed of block copolymers, wherein the block copolymers have segments containing ionic groups (hereinafter referred to as "ionic segments") and segments not containing ionic groups (hereinafter referred to as "nonionic segments"). The polymeric electrolyte material composed of such block polymers has the characteristic of readily forming a phase-separated structure. Hereinafter, the polymeric electrolyte material will sometimes be simply referred to as "electrolyte material".

[0042] The electrolyte material of the present invention has a phase-separated structure and satisfies at least one of conditions 1 and 2 below. Such an electrolyte material achieves both high levels of mechanical durability and proton conductivity.

[0043] <Condition 1> The saturated crystallinity of the polymeric electrolyte material, as determined by wide-angle X-ray diffraction, is above 5% and below 30%.

[0044] <Condition 2> The ion exchange capacity (IEC) of the polymer electrolyte material is 1.8 meq / g or more and 3.0 meq / g or less, and the product of the IEC (meq / g) of the polymer electrolyte material and the heat of crystallization (J / g) of the polymer electrolyte material as determined by differential scanning calorimetry is 35.0 or more and 47.0 or less.

[0045] Hereinafter, the saturated crystallinity of polymeric electrolyte materials determined by wide-angle X-ray diffraction will sometimes be abbreviated as "saturated crystallinity", the ion exchange capacity will be abbreviated as "IEC", and the heat of crystallization determined by differential scanning calorimetry will be abbreviated as "heat of crystallization".

[0046] In this invention, the so-called simultaneous achievement of high levels of mechanical durability and proton conductivity specifically refers to: relatively good mechanical durability and excellent proton conductivity, or relatively good proton conductivity and excellent mechanical durability.

[0047] In this invention, "good mechanical durability" refers to a small wet-dry dimensional change rate of the electrolyte membrane made of the electrolyte material. Here, the wet-dry dimensional change rate of the electrolyte membrane can be determined by the following measurement: A wet-dry cycle is repeatedly performed, in which a certain stress is applied to the electrolyte membrane test piece while it is alternately exposed to a dry atmosphere (30% RH) and a humidified atmosphere (90% RH). The dimensional change rate (%) at 30% RH and the dimensional change rate (%) at 90% RH are measured in the 10th cycle, and the difference is taken as the wet-dry dimensional change rate (%).

[0048] In this invention, the confirmation of the phase separation structure of the electrolyte material, the determination of the saturated crystallinity and heat of crystallization of the electrolyte material, and the evaluation of the mechanical durability (dry-wet dimensional change rate) and proton conductivity of the electrolyte material are performed using a membrane (hereinafter referred to as "electrolyte membrane") obtained by coating a solution containing the electrolyte material dissolved or dispersed in a suitable solvent onto a supporting substrate and then drying it. Hereinafter, the electrolyte material will sometimes be replaced with an electrolyte membrane in the description.

[0049] [Phase Separation Structure]

[0050] The electrolyte material of the present invention has a phase-separated structure. Here, "the electrolyte material has a phase-separated structure" means that the phase-separated structure can be confirmed when the electrolyte membrane is observed using a transmission electron microscope (TEM).

[0051] The morphology of the phase separation structure of the electrolyte membrane is illustrated in... Figure 1In general, phase separation structures can be classified into four types: co-continuous (M1), layer (M2), columnar (M3), and island (M4). The electrolyte material of this invention has any of the phase separation structures (M1) to (M4).

[0052] exist Figure 1 In (M1) to (M4), the continuous phase (phase 1) of the white part is formed by a segment selected from ionic and nonionic segments, and the continuous or dispersed phase (phase 2) of the gray part is formed by another segment.

[0053] The aforementioned phase separation structures are described, for example, in the Annual Review of Physical Chemistry, 41, 1990, p. 525.

[0054] By controlling the higher-order structure and shape of ionic and non-ionic chain segments, excellent proton conductivity can be achieved even under low humidification and low temperature conditions. That is, by giving the electrolyte membrane a phase-separated structure of (M1) to (M4), continuous proton conduction channels can be formed, thereby improving proton conductivity.

[0055] In the phase-separated structure consisting of a co-continuous (M1) and layered (M2) phases, both ionic and non-ionic segments form a continuous phase. Electrolyte membranes with such a phase-separated structure exhibit excellent proton conductivity due to the formation of continuous proton conduction channels, and excellent mechanical durability due to the crystallinity of the domains formed by the non-ionic segments. That is, the electrolyte material of the present invention preferably has a co-continuous (M1) phase-separated structure or a layered (M2) phase-separated structure, and preferably has a co-continuous (M1) phase-separated structure.

[0056] The aforementioned domain refers to a block formed by the aggregation of similar segments from one or more polymer chains.

[0057] The presence of a co-continuous (M1) or layered (M2) phase-separated structure in an electrolyte membrane can be confirmed by the following method. Specifically, a structure is defined as having this structure when a desired image is observed using the following method. This method involves comparing three-dimensional images obtained through TEM tomography, taken as digital slices cut along three directions: longitudinal, transverse, and height. For example, in an electrolyte membrane containing a block copolymer with ionic and nonionic segments, if the phase separation structure is co-continuous (M1) or layered (M2), in all three-dimensional images, both the hydrophilic domains containing ionic segments and the hydrophobic domains containing nonionic segments form a continuous phase.

[0058] In the case of cocontinuous state (M1), a pattern is shown where the continuous phases are entangled with each other; in the case of layered state (M2), a pattern is shown where the continuous phases are connected in layers. Here, a continuous phase refers to a phase in which the domains are not isolated but connected when viewed macroscopically, although there may be locally unconnected parts.

[0059] On the other hand, in the case of column structure (M3) and island structure (M4), none of the above domains form a continuous phase on at least one side, so they can be distinguished from the above co-continuous state (M1) and layered state (M2). In addition, the structure can also be identified based on the patterns shown in the three-view diagrams.

[0060] In the observation of phase-separated structures, in order to clarify the aggregation state and contrast of ionic and non-ionic segments, for example, the electrolyte membrane can be immersed in a 2% lead acetate aqueous solution for 2 days. After the ionic groups are ion-exchanged by lead, it can be used for observation by transmission electron microscopy (TEM) and TEM tomography.

[0061] The size of a phase-separated structure can be expressed as the periodic size of hydrophilic domains containing ionic segments and hydrophobic domains containing nonionic segments. The periodic size of the phase-separated structure can be estimated by an autocorrelation function obtained from image processing of the phase-separated structure observed by transmission electron microscopy (TEM).

[0062] From the viewpoint of proton conductivity and mechanical durability, the average period size of the aforementioned phase-separated structure is preferably in the range of 15–100 nm, more preferably in the range of 35–80 nm, even more preferably in the range of 40–67 nm, and particularly preferably in the range of 48–67 nm. Furthermore, if the average period size of the phase-separated structure is greater than 100 nm, it is difficult to form a co-continuous phase-separated structure. Therefore, from the viewpoint of obtaining a co-continuous phase-separated structure, the average period size is also preferably within the aforementioned range.

[0063] [Electrolyte material according to the first embodiment]

[0064] The electrolyte material (hereinafter referred to as "electrolyte material (I)") according to the first embodiment of the present invention satisfies condition 1. That is, the saturated crystallinity of electrolyte material (I) is 5% or more and 30% or less.

[0065] (Degree of saturation crystallinity)

[0066] The so-called saturated crystallinity refers to the degree of crystallinity at which crystallization no longer proceeds, i.e., the maximum crystallinity. Specifically, for the electrolyte membrane composed of the above-mentioned electrolyte material, it is heated and pressurized at 4.5 MPa at a temperature above the glass transition temperature (Tg) of the electrolyte material, and the crystallinity is measured every 5 minutes by wide-angle X-ray diffraction. The crystallinity at which it no longer changes is taken as the saturated crystallinity. The heating temperature (T (°C)) during heating and pressurization is set in the range of Tg ≤ T ≤ Tg + 40°C. Specifically, Tg + 5°C is appropriate.

[0067] From the viewpoint of improving mechanical durability, the saturated crystallinity of the electrolyte material (I) is preferably 7% or more, more preferably 9% or more, and particularly preferably 10% or more. On the other hand, if the saturated crystallinity of the electrolyte material (I) is greater than 30%, the proton conductivity and processability decrease. From the viewpoint of proton conductivity and processability, the aforementioned saturated crystallinity is preferably 25% or less, more preferably 23% or less, further preferably 20% or less, and particularly preferably 17% or less.

[0068] When electrolyte materials are used in electrochemical applications such as solid polymer fuel cells and water electrolysis hydrogen generators, they are typically processed into electrolyte molded membranes as described later. The crystallinity of the electrolyte molded membrane using electrolyte material (I) can reach the aforementioned saturated crystallinity, but it is not necessary to reach saturated crystallinity.

[0069] Regarding electrolyte molded films using electrolyte material (I), specifically those composed of block copolymers having ionic and nonionic segments, they exhibit good mechanical durability and excellent proton conductivity even when their crystallinity does not reach the saturation crystallinity of the electrolyte material. For example, it has been confirmed that even in a state where the electrolyte molded film has hardly undergone crystallization, it still exhibits good mechanical durability and excellent proton conductivity.

[0070] The crystallinity of the electrolyte-formed membrane using electrolyte material (I) can be increased by heating it at a temperature above the glass transition temperature of electrolyte material (I). This further improves the proton conductivity and mechanical durability of the electrolyte-formed membrane. At this point, the crystallinity of the electrolyte-formed membrane can be increased to the same level as the saturated crystallinity of electrolyte material (I), or it can be increased to approximately 1% to 99% of the saturated crystallinity of electrolyte material (I). The method for adjusting the crystallinity of the electrolyte-formed membrane is described later.

[0071] The IEC of the electrolyte material (I) is not particularly limited, but it is preferably 1.5 meq / g or more, more preferably 1.8 meq / g or more, further preferably 1.9 meq / g or more, and particularly preferably 2.0 meq / g or more. Furthermore, the IEC of the electrolyte material (I) is preferably 3.5 meq / g or less, more preferably 3.0 meq / g or less, further preferably 2.9 meq / g or less, and particularly preferably 2.8 meq / g or less.

[0072] The term IEC refers to the molar amount of ion-exchange groups introduced per unit dry mass of an electrolyte material (block copolymer). IEC can be determined by elemental analysis, neutralization titration, etc. When the ion-exchange group is a sulfonic acid group, it can also be calculated from the S / C ratio using elemental analysis; however, this is difficult to perform in cases where sulfur sources other than sulfonic acid groups are present. Therefore, in this invention, IEC is defined as the value obtained by the neutralization titration method described later.

[0073] [Electrolyte material according to the second embodiment]

[0074] The electrolyte material according to the second embodiment of the present invention (hereinafter referred to as "electrolyte material (II)") satisfies condition 2. That is, the electrolyte material (II) has an IEC of 1.8 meq / g or more and 3.0 meq / g or less, and the product of IEC and heat of crystallization is 35.0 or more and 47.0 or less.

[0075] (IEC)

[0076] The electrolyte material (II) has an IEC of 1.8 meq / g or higher and 3.0 meq / g or lower. Electrolyte materials (II) with an IEC in the above range exhibit excellent proton conductivity. From the viewpoint of improving proton conductivity, the IEC of electrolyte material (II) is preferably 1.9 meq / g or higher, more preferably 2.0 meq / g or higher, even more preferably 2.1 meq / g or higher, and particularly preferably 2.2 meq / g or higher. Furthermore, from the viewpoint of ensuring high mechanical durability, the IEC is preferably 2.9 meq / g or lower, more preferably 2.8 meq / g or lower, and particularly preferably 2.6 meq / g or lower.

[0077] (Crystallization heat)

[0078] Electrolyte material (II) is crystalline. Here, "crystallization" refers to the property of crystallizing upon heating. The degree of crystallinity can be expressed as the heat of crystallization obtained by differential scanning calorimetry (DSC). It should be noted that one indicator of whether an electrolyte material is crystalline is a heat of crystallization of 0.1 J / g or higher.

[0079] The differential scanning calorimetry (DSC) method used in this invention can employ the following analytical method.

[0080] Inside the DSC apparatus, after pre-drying 10 mg of the test sample (electrolyte membrane) at 110°C for 3 hours, the test sample was heated to 200°C without being removed from the DSC apparatus under the following conditions, and temperature-modulated differential scanning calorimetry (DSC) was performed during the heating phase. Here, the test sample used was the electrolyte membrane obtained by coating a solution containing an electrolyte material dissolved or dispersed in a suitable solvent onto a support substrate and then drying it.

[0081] • Measurement temperature range: 30℃~200℃

[0082] • Temperature control: AC temperature control

[0083] • Heating rate: 2℃ / min

[0084] • Amplitude: ±3℃

[0085] • Application frequency: 0.02Hz

[0086] • Sample tray: Aluminum crucible

[0087] • Atmosphere for measurement and pre-drying: Nitrogen 100 mL / min.

[0088] Compared with previous analytical methods, the differential scanning calorimetry (DSC) method described above does not expose the test sample to the atmosphere (air) from pre-drying to measurement. Therefore, it has the advantage that the test sample is not easily affected by the moisture in the atmosphere, thereby improving the measurement accuracy.

[0089] (The product of IEC and heat of crystallization)

[0090] The product of the IEC (meq / g) and the heat of crystallization (J / g) of the electrolyte material (II) is 35.0 or more and 47.0 or less.

[0091] As mentioned above, proton conductivity and mechanical durability are usually mutually restrictive. However, in the region where the IEC is above 1.8 meq J / g and below 3.0 meq / g, proton conductivity and mechanical durability can be achieved at a high level simultaneously by making the product of IEC and heat of crystallization above 35.0 and below 47.0.

[0092] As mentioned above, proton conductivity and mechanical durability in electrolyte membranes are generally mutually restrictive. Furthermore, proton conductivity is roughly correlated with IEC (internal conductivity equivalence), and mechanical durability is roughly correlated with heat of crystallization. That is, the vectors of IEC and heat of crystallization are in opposite directions. The inventors of this application have discovered that a physical quantity obtained by multiplying IEC by heat of crystallization is effective as an indicator of simultaneously achieving proton conductivity and mechanical durability. Moreover, in the region where IEC is 1.8 meq / g or higher and 3.0 meq / g or lower, the physical quantity obtained by multiplying IEC by heat of crystallization works particularly effectively. When this physical quantity is in the range of 35.0 or higher and 47.0 or lower, proton conductivity and mechanical durability can be simultaneously achieved at a high level.

[0093] From the above perspective, the product of IEC and heat of crystallization is preferably 36.0 or more and 47.0 or less, more preferably 37.0 or more and 44.0 or less.

[0094] The heat of crystallization of the electrolyte material (II) is designed such that the product of the IEC and the heat of crystallization is within the aforementioned range. Specifically, the heat of crystallization is preferably 12.0 J / g or more, more preferably 13.0 J / g or more, and particularly preferably 14.0 J / g or more. Furthermore, the heat of crystallization of the electrolyte material (II) is preferably 25.0 J / g or less, more preferably 24.0 J / g or less, and particularly preferably 23.0 J / g or less. If the heat of crystallization increases beyond the aforementioned range, the electrolyte membrane is prone to becoming brittle; on the other hand, if the heat of crystallization is less than the aforementioned range, mechanical durability is prone to decrease.

[0095] The IEC of electrolyte material (II) can be adjusted by controlling, for example, the density of sulfonic acid groups in the block copolymer and the content of ionic segments in the block copolymer. The heat of crystallization of electrolyte material (II) can be adjusted by controlling, for example, the structure of nonionic segments, the molecular weight of nonionic segments, and the content of nonionic segments in the block copolymer. Details are explained later.

[0096] Hereinafter, matters common to the electrolyte materials of the present invention, including the electrolyte materials according to the first embodiment and the electrolyte materials according to the second embodiment, will be described. It should be noted that when referred to as "electrolyte materials of the present invention" in the following description, both electrolyte material (I) and electrolyte material (II) are included.

[0097] [Block copolymer]

[0098] The electrolyte material of the present invention is composed of block copolymers having ionic and nonionic segments respectively. In the present invention, a segment refers to a portion of the structure of the macromonomer used in the synthesis of the block copolymer within the block copolymer. Furthermore, although it is stated that the nonionic segments do not contain ionic groups, a small amount of ionic groups may be included to a extent that does not adversely affect the effects of the present invention, particularly its crystallinity.

[0099] In the block copolymer constituting the polymer electrolyte material of the present invention, two or more incompatible chain segments—namely, ionic segments as hydrophilic segments and nonionic segments as hydrophobic segments—are linked to form a single polymer chain. In the block copolymer, phase separation occurs through short-range interactions arising from the repulsion between chemically different chain segments, resulting in nanodomains or microdomains formed by each chain segment. Furthermore, due to the covalent bonding between the chain segments, long-range interactions occur, allowing the domains to be arranged in a specific order. The higher-order structure resulting from the aggregation of domains formed by each chain segment is called a nanophase-separated structure or a microphase-separated structure. Here, a domain refers to a block formed by the aggregation of similar segments from one or more polymer chains. For ion conduction in electrolyte membranes, the spatial arrangement of ion-conducting segments in the membrane, i.e., the nanophase-separated structure or microphase-separated structure, becomes important.

[0100] [Ionic segments]

[0101] From the viewpoint of crystallinity and mechanical durability, the ionic segments in the block copolymer constituting the polymer electrolyte material of the present invention are preferably hydrocarbon polymers. Here, "hydrocarbon" refers to polymers other than perfluorinated polymers, and "hydrocarbon polymer" refers to polymers other than perfluorinated polymers.

[0102] Furthermore, from the viewpoint of crystallinity and mechanical durability, the ionic segment is preferably a hydrocarbon polymer having an aromatic ring on the main chain (hereinafter referred to as "aromatic hydrocarbon polymer").

[0103] Aromatic hydrocarbon polymers contain not only hydrocarbon aromatic rings but also heterocycles. Furthermore, some aliphatic units can also form polymers together with aromatic ring units. Specific examples of aromatic hydrocarbon polymers include those with aromatic rings on the main chain and polymers selected from polysulfone, polyethersulfone, polyphenylene ether, polyarylene ether polymers, polyphenylene sulfide, polyphenylene sulfide sulfone, poly(p-phenylene), polyarylene polymers, polyarylene ketones, polyether ketones, polyarylene phosphine oxide, polyether phosphine oxide, and polybenzo[a]benzene. Polymers with structures derived from azoles, polybenzothiazoles, polybenzimidazoles, polyamides, polyimides, polyetherimides, and polyimide sulfones are preferred, considering cost and polymerizability.

[0104] Aromatic polyether polymers refer to polymers that are mainly composed of aromatic rings and contain at least ether bonds in the repeating units, where aromatic ring units are linked together. Examples of aromatic polyether polymer structures include, but are not limited to, aromatic polyethers, aromatic polyether ketones, aromatic polyether imides, and aromatic polyether sulfones. From the perspective of chemical stability and cost, aromatic polyether ketone polymers and aromatic polyether sulfone polymers are preferred; from the viewpoint of mechanical and physical durability, aromatic polyether ketone polymers are most preferred.

[0105] Aromatic polyetherketone polymers refer to polymers mainly composed of aromatic rings, in which at least ether bonds and ketone bonds are linked by aromatic ring units in the repeating units. Aromatic polyetherketone polymers include aromatic polyetherketones, aromatic polyetheretherketones, aromatic polyetherketoneketones, aromatic polyetheretherketoneketones, and aromatic polyetherketoneetherketoneketones, etc.

[0106] Aromatic polyethersulfone polymers refer to polymers that are mainly composed of aromatic rings and contain at least ether bonds and sulfone bonds in the repeating units, which are linked by aromatic ring units.

[0107] The ionic segments used in this invention can be synthesized through aromatic nucleophilic substitution reactions, coupling reactions, etc.

[0108] As described above, the ionic segments are preferably aromatic polyether polymers, which preferably contain the structure represented by the following general formula (S1).

[0109] *-Ar 1 -Y 1 -Ar 2 -O-Ar 3 -Y 2 -Ar 4 -O-* (S1)

[0110] In general formula (S1), Ar 1 ~Ar 4 Ar represents substituted arylene or unsubstituted arylene, respectively. 1 ~Ar 4 At least one of them has an ionic group. 1 and Y 2 Each group represents a ketone group and a protecting group that can be derived into a ketone group. * indicates a bond with the general formula (S1) or other structural units.

[0111] Here, as Ar 1 ~Ar 4Examples of arylene groups include hydrocarbon-based arylene groups such as phenylene, naphthylene, biphenylene, and fluorenediyl, as well as heteroarylene groups such as pyridinyl, quinoxalinediyl, and thiophenediyl, but these are not limited to these. Ionic groups are preferably negatively charged atomic groups, and more preferably groups with proton exchange capability. Examples of such functional groups include sulfonic acid groups, sulfonylimide groups, sulfate groups, phosphonic acid groups, phosphate groups, and carboxylic acid groups, but these are not limited to these.

[0112] The aforementioned ionic groups include those that form salts. Examples of cations that form salts include any metal cation, NR4, etc. + Examples include (R being any organic group). There are no particular restrictions on the metal cation, but Na, K, and Li, which are inexpensive and can be easily proton-substituted, are preferred.

[0113] These ionic groups can include two or more types in the ionic chain segment, and the combination can be suitably determined according to the structure of the block copolymer. Among them, from the perspective of high proton conductivity, it is more preferable to contain at least a sulfonic acid group, a sulfonyl imide group, and a sulfate group, and from the perspective of raw material cost, it is particularly preferable to contain a sulfonic acid group.

[0114] Furthermore, in general formula (S1), from the viewpoint of forming a phase-separated structure, Y 1 and Y 2 The protecting group is preferably a ketone group or a protecting group capable of being derived into a ketone group. That is, the ionic segment is preferably an aromatic polyether ketone polymer. The protecting group capable of being derived into a ketone group will be explained later.

[0115] The structure represented by the above general formula (S1) is preferably the structure represented by the following general formula (P1) from the perspective of raw material availability, and is further preferably the structure represented by the following general formula (S2) from the perspective of raw material availability and polymerizability.

[0116]

[0117] In general formulas (P1) and (S2), Y 1 and Y 2 Each protector group independently represents a ketone group or a protecting group capable of being derived into a ketone group. M 1 ~M 4 Each of the following can independently represent a hydrogen atom, a metal cation, or an ammonium cation. n1 to n4 are independently 0 or 1, and at least one of n1 to n4 is 1. * indicates a bond with general formula (P1), (S2), or other structural units.

[0118] Furthermore, considering the availability of raw materials and the polymerizability, the optimal values ​​are n1=1, n2=1, n3=0, n4=0 or n1=0, n2=0, n3=1, n4=1.

[0119] Examples of ionic monomers used as structural units for synthesizing such ionic segments include, for example, aromatic active dihalides. When using aromatic active dihalides in ionic segments, compounds obtained by introducing ionic acid groups into aromatic active dihalides are preferred, considering the ability to precisely control chemical stability, manufacturing costs, and the amount of ionic groups. Preferred examples of monomers having sulfonic acid groups as ionic groups include 3,3'-disulfonate-4,4'-dichlorodiphenyl sulfone, 3,3'-disulfonate-4,4'-difluorodiphenyl sulfone, 3,3'-disulfonate-4,4'-dichlorodiphenyl ketone, 3,3'-disulfonate-4,4'-difluorodiphenyl ketone, 3,3'-disulfonate-4,4'-dichlorodiphenylphenyl phosphine oxide, and 3,3'-disulfonate-4,4'-difluorodiphenylphenyl phosphine oxide, but these are not the only options available.

[0120] Considering proton conductivity and hydrolysis resistance, sulfonic acid groups are the most preferred ionic groups, but monomers with the above-mentioned ionic groups can also have other ionic groups.

[0121] Among the monomers with sulfonic acid groups mentioned above, 3,3'-disulfonate-4,4'-dichlorodiphenyl ketone and 3,3'-disulfonate-4,4'-difluorodiphenyl ketone are more preferred in terms of chemical stability and physical durability, and 3,3'-disulfonate-4,4'-difluorodiphenyl ketone is most preferred in terms of polymerization activity.

[0122] The ionic segments synthesized using 3,3'-disulfonate-4,4'-dichlorodiphenyl ketone and 3,3'-disulfonate-4,4'-difluorodiphenyl ketone as monomers with ionic groups are preferred because they contain structural units represented by the following general formula (p1). In addition to possessing the high crystallinity characteristic of ketone groups, this aromatic polyether polymer exhibits superior hot water resistance compared to sulfonic acid groups, making it an effective component for materials with excellent dimensional stability, mechanical strength, and physical durability under high temperature and humidity conditions. For these sulfonic acid groups, it is preferable that the sulfonic acid groups form a salt with a monovalent cation during polymerization. The monovalent cation can be sodium, potassium, other metals, various amines, etc., but is not limited to these. These aromatic active dihalides can be used alone or in combination with multiple aromatic active dihalides.

[0123]

[0124] (In general formula (p1), M) 1 and M 2The symbols represent hydrogen, metal cations, and ammonium cations, respectively, with a1 and a2 representing integers from 1 to 4. The structural unit represented by the general formula (p1) can be arbitrarily substituted.

[0125] Furthermore, as aromatic active dihalides, the density of ionic groups can be controlled by copolymerizing aromatic active dihalides with ionic groups and aromatic active dihalides without ionic groups. However, from the viewpoint of ensuring the continuity of the proton conduction channel, it is more preferable not to copolymerize aromatic active dihalides without ionic groups, as the aforementioned ionic segments.

[0126] Specific examples of more preferred aromatic active dihalides that do not possess ionic groups include 4,4'-dichlorodiphenyl sulfone, 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl ketone, 4,4'-difluorodiphenyl ketone, 4,4'-dichlorodiphenylphenylphosphine oxide, 4,4'-difluorodiphenylphenylphosphine oxide, 2,6-dichlorobenzonitrile, and 2,6-difluorobenzonitrile. Among these, 4,4'-dichlorodiphenyl ketone and 4,4'-difluorodiphenyl ketone are more preferred in terms of crystallinity, mechanical strength, physical durability, and hot water resistance, and 4,4'-difluorodiphenyl ketone is most preferred in terms of polymerization activity. These aromatic active dihalides can be used alone or in combination with multiple aromatic active dihalides.

[0127] As a polymeric electrolyte material synthesized using 4,4'-dichlorodiphenyl ketone and 4,4'-difluorodiphenyl ketone as aromatic active dihalides, it is preferred to use a material that also contains the constituent site represented by the following general formula (p2). This structural unit becomes a component that imparts intermolecular cohesion and crystallinity, and thus becomes a material with excellent dimensional stability, mechanical strength, and physical durability under high temperature and high humidity conditions.

[0128]

[0129] (The structural unit represented by the general formula (p2) can be arbitrarily replaced, but it does not contain ionic groups.)

[0130] In addition, aromatic bisphenol compounds can be cited as nonionic monomers for synthesizing ionic segments, and aromatic bisphenol compounds having the protecting group described later are particularly preferred.

[0131] The monomers used to synthesize the structural units of ionic segments have been described above.

[0132] In addition to the structures represented by general formula (S1), the structures represented by general formulas (T1) and (T2) can also be included as ionic segments or as structural units constituting ionic segments.

[0133]

[0134] In general formulas (T1) and (T2), B represents a divalent organic group containing an aromatic ring. M 5 and M 6 Each can be used independently to represent a hydrogen atom, a metal cation, or an ammonium cation.

[0135] In this aromatic polyether ketone copolymer, the ion exchange capacity can be controlled by changing the composition ratio of the structural units represented by general formulas (T1) and (T2).

[0136] As ionic segments, structures represented by general formula (P1) and general formulas (T1) and (T2) are particularly preferred. In such ionic segments, when the amounts of structural units represented by general formulas (P1), (T1), and (T2) are set as p1, t1, and t2, respectively, p1 is preferably 75 molar parts or more, more preferably 90 molar parts or more, and even more preferably 100 molar parts or more, relative to the total molar amount of t1 and t2, i.e., 100 molar parts.

[0137] As the divalent organic group B containing an aromatic ring in general formulas (T1) and (T2), examples include residues of various diphenolic compounds that can be used in the polymerization of aromatic polyether polymers via aromatic nucleophilic substitution reactions, and residues obtained by introducing sulfonic acid groups into them.

[0138] Preferred examples of divalent organic groups B containing aromatic rings include groups represented by the following general formulas (X'-1) to (X'-6), but are not limited to these.

[0139]

[0140] They can have ionic groups or aromatic groups. In addition, they can be combined as needed. Among them, from the viewpoint of crystallinity, dimensional stability, toughness and chemical stability, groups represented by general formulas (X'-1) to (X'-4) are more preferred, and groups represented by general formulas (X'-2) and (X'-3) are most preferred.

[0141] [Nonionic segments]

[0142] From the viewpoint of crystallinity and mechanical durability, the nonionic segments constituting the block copolymers of the present invention are preferably hydrocarbon polymers, and more preferably aromatic hydrocarbon polymers. Here, the definition of hydrocarbon polymers and specific examples of aromatic hydrocarbon polymers are as described above.

[0143] Among aromatic hydrocarbon polymers, aromatic polyether polymers are preferred from the perspective of cost and polymerizability, while aromatic polyether ketone polymers and aromatic polyether sulfone polymers are preferred from the perspective of mechanical durability and physical durability, and aromatic polyether ketone polymers are particularly preferred.

[0144] As described above, the nonionic segments are preferably aromatic polyether polymers, which preferably contain the structure represented by the following general formula (S3).

[0145] *-Ar 5 -Y 3 -Ar 6 -O-Ar 7 -Y 4 -Ar 8 -O-* (S3)

[0146] In general formula (S3), Ar 5 ~Ar 8 Each can be used independently to represent either a substituted arylene or an unsubstituted arylene. Where Ar... 5 ~Ar 8 Neither of them possesses ionic groups. 3 and Y 4 Each group represents a ketone group and a protecting group that can be derived into a ketone group. * indicates a bond with a general formula (S3) or other structural units.

[0147] Here, as Ar 5 ~Ar 8 Examples of arylene groups include phenylene, naphthylene, biphenylene, fluorenediyl, pyridinediyl, quinoxalinediyl, thiophenediyl, etc., but they are not limited to these.

[0148] Furthermore, in general formula (S3), from the viewpoint of forming a phase-separated structure, Y 3 and Y 4 The protecting group is a ketone group or a group that can be derived into a ketone group; therefore, the block copolymer is crystalline and readily forms a phase-separated structure. Specifically, the nonionic segments are preferably aromatic polyether ketone polymers.

[0149] From the perspective of raw material availability, it is preferable that the structure represented by the above general formula (S3) contains the structure represented by the following general formula (P2), wherein, from the perspective of mechanical durability, dimensional stability and physical durability based on crystallinity, it is even more preferable that the structure represented by the above general formula (S3) contains the structural unit represented by the following general formula (S4).

[0150]

[0151] In general formulas (P2) and (S4), Y3 and Y 4 Each protector group independently represents a ketone group or a protecting group that can be derived into a ketone group. * indicates a bond with general formula (P2) and (S4) or other structural units.

[0152] The content of the structure represented by the general formula (P2) or (S4) in the nonionic segment is preferably 20 mol% or more, more preferably 50 mol% or more, and particularly preferably 80 mol% or more, from the viewpoint of mechanical durability, dimensional stability, and physical durability.

[0153] As a protecting group capable of being derived into a ketone group, a protecting group containing, for example, at least one group selected from the following general formulas (P3) and (P4) is preferred.

[0154]

[0155] (In general formulas (P3) and (P4), Ar 11 ~Ar 14 For any divalent aryl group, R 1 and R 2 R is at least one group selected from H and alkyl groups. 3 These can be any alkylene group, and each can represent two or more groups. The groups represented by general formulas (P3) and (P4) can be arbitrarily substituted.

[0156] R in general formula (P3) 1 and R 2 From a stability perspective, alkyl is more preferred, alkyl with 1 to 6 carbon atoms is even more preferred, and alkyl with 1 to 3 carbon atoms is most preferred. Additionally, R in general formula (P4) 3 From a stability perspective, alkylene groups with 1 to 7 carbon atoms are more preferred, and alkylene groups with 1 to 4 carbon atoms are most preferred. As R 3 Specific examples include -CH2CH2-, -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -C(CH3)2CH(CH3)-, -C(CH3)2O(CH3)2-, -CH2CH2CH2-, -CH2C(CH3)2CH2-, etc., but are not limited to these.

[0157] Ar in the above general formulas (P3) and (P4) 11 ~Ar 14 The preferred organic groups are phenylene, naphthylene, or biphenylene. They can be substituted in any way. As an aromatic polyether polymer, considering solubility and ease of raw material availability, Ar in the above general formula (P4) is more preferred. 13 and Ar14 All are phenylene, with Ar being the most preferred. 13 and Ar 14 All are paraphenylene.

[0158] Here, as a method for protecting the ketone site using a ketal, one example is the reaction of a precursor compound having a ketone group with a monofunctional and / or difunctional alcohol in the presence of an acid catalyst. For example, it can be prepared by reacting 4,4'-dihydroxybenzophenone, a ketone precursor, with a monofunctional and / or difunctional alcohol in a solvent such as an aliphatic hydrocarbon or aromatic hydrocarbon in the presence of an acid catalyst such as hydrogen bromide. The alcohol is an aliphatic alcohol with 1 to 20 carbon atoms.

[0159] An improved method for manufacturing ketal monomers includes a step of reacting the ketone precursor 4,4'-dihydroxybenzophenone with a difunctional alcohol in the presence of an alkyl orthoester and a solid catalyst.

[0160] The method for deprotecting at least a portion of the ketone site protected by a ketal to form a ketone site is not particularly limited. The deprotection reaction described above can be carried out under heterogeneous or homogeneous conditions, in the presence of water and acid. However, from the viewpoints of mechanical strength, physical durability, and solvent resistance, acid treatment after molding into a film is more preferable. Specifically, deprotection can be performed by immersing the molded film in an aqueous solution of hydrochloric acid or sulfuric acid, and the concentration of the acid and the temperature of the aqueous solution can be appropriately selected.

[0161] The required acidic aqueous solution weight ratio for the polymer is preferably 1 to 100 times, but a larger amount of water can also be used. The acid catalyst is preferably used at a concentration of 0.1 to 50% by weight of the water present. Preferred acid catalysts include strong inorganic acids such as hydrochloric acid, nitric acid, fluorosulfonic acid, and sulfuric acid, as well as strong organic acids such as p-toluenesulfonic acid and trifluoromethanesulfonic acid. The acid catalyst, the amount of excess water, and the reaction pressure can be appropriately selected according to factors such as the polymer film thickness.

[0162] For example, a membrane with a thickness of 50 μm can be easily deprotected by immersing it in an acidic aqueous solution, such as a 6N hydrochloric acid solution, and heating it at 95°C for 1 to 48 hours. Furthermore, even immersion in a 1N hydrochloric acid solution at 25°C for 24 hours can deprotect most of the protecting groups. However, the deprotection conditions are not limited to these; deprotection can also be performed using acidic gases, organic acids, or by heat treatment.

[0163] In the case where aromatic polyether polymers contain bonding methods other than ether bonds such as direct linkages, from the perspective of improving processability, the position of the introduced protecting group is more preferably the aromatic ether polymer portion.

[0164] Specifically, for example, aromatic polyether polymers containing structural units represented by the above general formulas (P3) and (P4) can be synthesized using compounds represented by the following general formulas (P3-1) and (P4-1) as aromatic bisphenol compounds, through an aromatic nucleophilic substitution reaction with an aromatic active dihalide. The structural units represented by the above general formulas (P3) and (P4) can be derived from either aromatic bisphenol compounds or aromatic active dihalides, but considering the reactivity of the monomers, structural units derived from aromatic bisphenol compounds are more preferably used.

[0165]

[0166] (In general formulas (P3-1) and (P4-1), Ar) 11 ~Ar 14 Represents any divalent aryl group, R 1 and R 2 R represents at least one group selected from H and alkyl groups. 3 This indicates any alkylene group. Compounds represented by general formulas (P3-1) and (P4-1) can be substituted in any way.

[0167] The preferred protecting groups have been explained above.

[0168] [Detailed Description of Block Copolymers]

[0169] For the block copolymer constituting the polymeric electrolyte material of the present invention, both the ionic and nonionic segments are preferably aromatic polyether polymers, and more preferably aromatic polyetherketone polymers. In such a block copolymer, the IEC and heat of crystallization can be adjusted by controlling the molecular structure of each segment, the molecular weight of each segment, the molecular weight ratio of the two segments, the density of sulfonic acid groups, etc.

[0170] For example, the IEC of a block copolymer can be adjusted by controlling the density of sulfonic acid groups in the ionic segments and the content of ionic segments in the block copolymer.

[0171] Furthermore, for example, the saturation crystallinity and heat of crystallization of the block copolymer can be adjusted by changing the molecular weight of the nonionic segments and the content of nonionic segments in the block copolymer. Specifically, by making the number-average molecular weight of the nonionic segments 15,000 or more, the saturation crystallinity and heat of crystallization of the block copolymer can be increased to a desired range. That is, the nonionic segments constituting the block copolymer of the present invention are more preferably aromatic polyetherketone polymers with a number-average molecular weight of 15,000 or more.

[0172] In particular, the block copolymer constituting the polymer electrolyte material of the present invention preferably comprises ionic segments containing structural units represented by the above general formula (S1) and nonionic segments containing structural units represented by the above general formula (S3).

[0173] Nonionic segments containing structural units represented by the general formula (S3) are crystalline segments, and the desired saturation crystallinity and heat of crystallization can be adjusted by controlling the molecular weight of the nonionic segment and its content in the block copolymer.

[0174] Block copolymers comprising nonionic segments containing structural units represented by general formula (S3) can be manufactured, for example, by molding a block copolymer precursor in which a protecting group has been introduced into at least the nonionic segments, and then deprotecting at least a portion of the protecting group contained in the molded body. In block copolymers, compared to random copolymers, there is a tendency for processability to deteriorate due to the crystallization of the polymer that forms domains. Therefore, it is preferable to introduce a protecting group into at least the nonionic segments to improve processability. For ionic segments, it is also preferable to introduce a protecting group if processability deteriorates.

[0175] The block copolymers constituting the polymeric electrolyte materials of the present invention have a phase-separated structure. That is, in the block copolymers of the present invention, which respectively have ionic and nonionic segments, the hydrophilic domains formed by the aggregation of ionic segments have a locally high concentration of ionic groups, thereby exhibiting excellent proton conductivity. The hydrophobic domains formed by the aggregation of nonionic segments have strong intermolecular interactions due to crystallinity, thereby exhibiting excellent dimensional stability.

[0176] By making both the ionic and nonionic segments constituting the block copolymer aromatic polyether polymers (preferably aromatic polyether ketone polymers), a phase-separated structure can be easily formed. Furthermore, from the above perspective, the block copolymer of the present invention preferably comprises ionic segments containing structural units represented by the above general formula (S1) and nonionic segments containing structural units represented by the above general formula (S3).

[0177] Furthermore, the block copolymer constituting the polymer electrolyte material of the present invention preferably contains one or more connecting body sites that link ionic and nonionic segments. Such block copolymers are more likely to form co-continuous phase separation structures or layered phase separation structures.

[0178] The aforementioned linker is the site that connects ionic and nonionic chain segments, and is defined as a site having a chemical structure different from that of the ionic and nonionic chain segments.

[0179] The linker functions by suppressing the randomization of the copolymer caused by the ether exchange reaction, segment breakage, and other side reactions that may occur during copolymer synthesis, and by linking different segments together. Therefore, by using compounds that provide such linkers as raw materials, block copolymers can be obtained without reducing the molecular weight of each segment. Examples of linkers include, but are not limited to, decafluorobiphenyl, hexafluorobenzene, 4,4'-difluorodiphenyl sulfone, and 2,6-difluorobenzonitrile.

[0180] By controlling the number-average molecular weight of the ionic segments and the number-average molecular weight of the nonionic segments constituting the block copolymer (which constitutes the polymeric electrolyte material of the present invention), the IEC, saturation crystallinity, heat of crystallization, and average period size of the phase separation structure of the block copolymer can be adjusted to the desired ranges described above. For example, from the viewpoint of adjusting the IEC and the average period size of the phase separation structure to the desired range, the number-average molecular weight of the ionic segments is preferably in the range of 10,000 to 150,000, more preferably in the range of 20,000 to 120,000, and particularly preferably in the range of 45,000 to 100,000. On the other hand, from the viewpoint of adjusting the saturation crystallinity, heat of crystallization, and average period size of the phase separation structure to the desired range, the number-average molecular weight of the nonionic segments is preferably in the range of 5,000 to 50,000, more preferably in the range of 10,000 to 40,000, and particularly preferably in the range of 15,000 to 30,000.

[0181] To achieve a high number-average molecular weight (NMR) of the ionic segments, for example, 45,000 or higher, it is preferable to use linkers to bind the structural units within the ionic segments. Using linkers makes the synthesis of long-chain polymers easier. Examples of linkers include, but are not limited to, decafluorobiphenyl, hexafluorobenzene, 4,4'-difluorodiphenyl sulfone, and 2,6-difluorobenzonitrile.

[0182] Furthermore, in the block copolymer constituting the polymer electrolyte material of the present invention, when the number-average molecular weight of the ionic segments is set to Mn1 and the number-average molecular weight of the nonionic segments is set to Mn2, it is preferable to satisfy Formula 1 below, and more preferably to satisfy Formula 2 below. Such a block copolymer is preferred from the viewpoint of adjusting the average period size of the IEC, the heat of crystallization, and the phase separation structure to the above-mentioned range.

[0183] 1.7≦Mn1 / Mn2≦7.0 (Equation 1)

[0184] 2.0≦Mn1 / Mn2≦5.0 (Equation 2).

[0185] In particular, from the viewpoint of adjusting the IEC, saturated crystallinity, heat of crystallization and average period size of phase separation structure to the above range, it is preferable that the number average molecular weight (Mn2) of the nonionic segments is 15,000 or more, and satisfies Equations 1 and 2 above.

[0186] The following describes specific methods for synthesizing the block copolymers constituting the polymeric electrolyte materials of the present invention. However, the present invention is not limited to these methods.

[0187] From a process-friendly perspective, the segments in the block copolymer constituting the polymeric electrolyte material of the present invention are preferably synthesized via an aromatic nucleophilic substitution reaction. An aromatic nucleophilic substitution reaction is a method of reacting a monomer mixture of a dihalide and a diol compound in the presence of a basic compound. Polymerization can be carried out in a temperature range of 0–350°C, but is preferably in a temperature range of 50–250°C. The reaction can also be carried out under solvent-free conditions, but is preferably carried out in a solvent. Examples of usable solvents include, but are not limited to, aprotic polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolinone, and hexamethylphosphoric triamine, but any solvent that can be used as a stable solvent in an aromatic nucleophilic substitution reaction is acceptable. These organic solvents can be used alone or in mixtures of two or more.

[0188] Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate. Any compound capable of forming an active phenolate structure from diols can be used, and is not limited to these. Furthermore, adding crown ethers such as 18-crown-6-ether is suitable to improve the nucleophilicity of phenolates. Crown ethers sometimes incorporate sodium or potassium ions located at the sulfonic acid group, thereby improving the solubility of the sulfonate portion of monomers and polymers in organic solvents, and are therefore preferred.

[0189] In aromatic nucleophilic substitution reactions, water is sometimes generated as a byproduct. In this case, regardless of the polymerization solvent, toluene or similar substances can be coexisted in the reaction system to remove water as an azeotrope. Alternatively, desiccant such as molecular sieves can be used to remove water from the system.

[0190] The block copolymer constituting the polymer electrolyte material of the present invention can be manufactured as follows: after synthesizing the block copolymer precursor, at least a portion of the protecting groups contained in the precursor are deprotected. As a method for manufacturing the block copolymer and the block copolymer precursor of the present invention, it is preferable to include at least the following steps (1) to (2). By including these steps, it is possible to improve mechanical durability and durability by increasing the molecular weight, and by alternately introducing the two segments, it is possible to obtain a block copolymer with excellent low-humidification proton conductivity and strictly controlled phase separation structure and domain size.

[0191] Step (1): For one of the following chain segments—an ionic chain segment having -OM groups (M represents a hydrogen atom, a metal cation, or an ammonium cation) at both ends and a non-ionic chain segment having -OM groups at both ends—the -OM groups at both ends of the chain segment react with a linker compound to introduce the linker into the two ends of the chain segment.

[0192] Step (2): A step of polymerizing the two ends of the linker portion of the chain segment synthesized in step (1) with the -OM groups at the two ends of another chain segment, thereby producing a block copolymer or block copolymer precursor having ionic and nonionic chain segments.

[0193] Specific examples of chain segments represented by general formula (S1) with both ends having -OM groups and chain segments represented by general formula (S2) with both ends having -OM groups can be given as chain segments with structures represented by the following general formulas (H3-1) and (H3-2), respectively. Furthermore, as structures resulting from the reaction of chain segments with structures represented by general formulas (H3-1) and (H3-2) with halide linkers, for example, structures represented by the following general formulas (H3-3) and (H3-4) can be given. However, the present invention is not limited to these.

[0194]

[0195] In the above general formulas (H3-1) to (H3-4), N1, N2, N3, and N4 independently represent integers from 1 to 200.

[0196] When the ionic chain segment has a connector, as a specific example of an ionic chain segment with a connector portion obtained by the above-described step (1), structures represented by the following general formulas (H3-1L) and (H3-3L) can be cited. However, the present invention is not limited to these.

[0197]

[0198] In the above general formulas (H3-1L) to (H3-3L), N5 and N6 independently represent integers from 1 to 200.

[0199] In the general formulas (H3-1) to (H3-4), (H3-1L), and (H3-3L), halogen atoms are represented by F, terminal -OM groups are represented by -OK groups, and alkali metals are represented by Na and K, but their use is not limited to these specific formulas. Furthermore, these general formulas are inserted for the purpose of aiding the reader's understanding and do not necessarily accurately represent the chemical structure, precise composition, arrangement, position and number of sulfonic acid groups, molecular weight, etc., of the polymer's polymeric components; they are not limited to these specific formulas.

[0200] Furthermore, in general formulas (H3-1) to (H3-4), (H3-1L), and (H3-3L), a ketal group is introduced as a protecting group for any chain segment. However, in this invention, it is sufficient to introduce a protecting group into a component with high crystallinity and low solubility. Therefore, for the aforementioned ionic chain segments, a protecting group is not necessarily required, and from the viewpoint of durability and dimensional stability, it is preferable to use a chain segment without a protecting group.

[0201] [Polymer Electrolyte Molded Body]

[0202] The electrolyte material of the present invention is suitable as a polymeric electrolyte molded body. Here, "polymeric electrolyte molded body" refers to a molded body containing the electrolyte material of the present invention. As such a polymeric electrolyte molded body, in addition to membranes (including membranes and membrane-like structures), it can also take various forms such as plate-like, fibrous, hollow filament-like, particle-like, block-like, microporous, coating-like, and foam-like forms, depending on the application. Among these, membrane-like forms are preferred from the perspective of adaptability to a wide range of applications. Hereinafter, membrane-like polymeric electrolyte molded bodies will be referred to as "electrolyte molded membranes". Hereinafter, electrolyte molded membranes will be used as representative examples of polymeric electrolyte molded bodies, but the present invention is not limited thereto.

[0203] Methods for manufacturing electrolyte molded films include methods of forming films from a solution state while having protective groups such as ketals, and methods of forming films from a molten state. In the former, for example, the following method can be used: dissolving an electrolyte material in a solvent such as N-methyl-2-pyrrolidone, casting the solution onto a glass plate, a polyethylene terephthalate film (hereinafter referred to as PET film), etc., and then removing the solvent to form a film.

[0204] As a solvent for film formation, any solvent capable of dissolving and subsequently removing the electrolyte material is suitable. Suitable solvents include, for example, aprotic polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolinone, and hexamethylphosphoric triamine; ester solvents such as γ-butyrolactone and butyl acetate; carbonate solvents such as ethylene carbonate and propylene carbonate; alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; alcohol solvents such as isopropanol; water; and mixtures thereof. However, aprotic polar solvents have the highest solubility and are therefore preferred. Additionally, adding crown ethers such as 18-crown-6-ether is also suitable to improve the solubility of ionic segments.

[0205] As a method for converting the electrolyte material of the present invention into an electrolyte-molded membrane, one example is the following method: after forming a membrane composed of the electrolyte material by the above method, at least a portion of the sites protected by the protective group is deprotected. For example, in the case where a ketal site is used as the protective group, at least a portion of the ketone sites protected by the ketal site is deprotected to form ketone sites. According to this method, solution film formation of block copolymers with insufficient solubility becomes possible, and proton conductivity, mechanical durability, and physical durability can be achieved simultaneously.

[0206] Alternatively, the following steps can be performed: after forming a film in a state where the contained ionic groups have formed a salt with the cations of an alkali metal or alkaline earth metal, the cations of the alkali metal or alkaline earth metal are exchanged with protons. This step is preferably a step of contacting the formed film with an acidic aqueous solution, and more preferably a step of immersing the formed film in an acidic aqueous solution. In this step, the protons in the acidic aqueous solution are replaced by the cations that have already formed ionic bonds with the ionic groups, and residual water-soluble impurities, residual monomers, solvents, residual salts, etc., are simultaneously removed.

[0207] There are no particular limitations on the acidic aqueous solution, but sulfuric acid, hydrochloric acid, nitric acid, acetic acid, trifluoromethanesulfonic acid, methanesulfonic acid, phosphoric acid, citric acid, etc., are preferred. The temperature and concentration of the acidic aqueous solution should also be appropriately determined, but from a productivity point of view, it is preferable to use an aqueous solution of sulfuric acid with a mass percentage of 3% to 30% at a temperature above 0°C and below 80°C.

[0208] From the viewpoint of mechanical and physical durability, the thickness of the electrolyte molding membrane in this invention is preferably 1 μm or more, more preferably 2 μm or more, and particularly preferably 3 μm or more. On the other hand, from the viewpoint of power generation performance, it is preferably 500 μm or less, more preferably 300 μm or less, and particularly preferably 200 μm or less.

[0209] In addition, the electrolyte molding membrane may contain additives such as crystal nucleating agents, plasticizers, stabilizers, antioxidants or release agents commonly used in polymer compounds, without departing from the purpose of this invention.

[0210] Furthermore, electrolyte-molded membranes can contain various polymers, elastomers, fillers, microparticles, and additives to improve mechanical strength, thermal stability, and processability, without adversely affecting the aforementioned properties. Additionally, electrolyte-molded membranes can be reinforced using microporous membranes, nonwoven fabrics, webs, etc.

[0211] Electrolyte-formed membranes can be applied to a wide range of uses. For example, they can be used in medical applications such as artificial skin, filtration, ion exchange resin applications such as chlorine-resistant reverse osmosis membranes, various structural materials, electrochemical applications, humidification membranes, anti-fogging membranes, antistatic membranes, deoxygenation membranes, solar cell membranes, and gas barrier membranes. Among these, their application in various electrochemical applications is particularly advantageous. Examples of electrochemical applications include solid polymer fuel cells, redox flow batteries, water electrolysis devices, chlor-alkali electrolysis devices, electrochemical hydrogen pumps, and water electrolysis hydrogen generators.

[0212] In solid polymer fuel cells, electrochemical hydrogen pumps, and water electrolysis hydrogen generators, electrolyte molded membranes are used in the form of a structure obtained by sequentially stacking a catalyst layer, an electrode substrate, and a separator on both sides. The structure obtained by stacking catalyst layers on both sides of the electrolyte molded membrane (i.e., a structure consisting of catalyst layer / electrolyte molded membrane / catalyst layer layers) is called a catalyst-coated electrolyte membrane (CCM), and the structure obtained by further sequentially stacking catalyst layers and a gas diffusion substrate on both sides of the electrolyte molded membrane (i.e., a structure consisting of gas diffusion substrate / catalyst layer / electrolyte molded membrane / catalyst layer / gas diffusion substrate layers) is called a membrane electrode assembly (MEA). The electrolyte material of the present invention is particularly suitable as an electrolyte molded membrane constituting such a CCM and MEA.

[0213] Electrolyte-formed films can be manufactured, for example, by casting an electrolyte solution, in which an electrolyte material is dissolved or dispersed in a suitable solvent, onto a supporting substrate (glass plate, PET film, etc.), followed by drying. The electrolyte-formed film obtained as described above can be acid-treated, washed with water, and dried as needed. In the drying process described above, the crystallinity of the electrolyte-formed film can be increased by drying at or above the glass transition temperature of the electrolyte material, or by heating at the aforementioned temperature after drying. The crystallinity of the electrolyte-formed film can be adjusted by controlling the heating temperature and heating time.

[0214] In addition, during the heating and pressurizing process of manufacturing the electrolyte membrane (CCM) with a catalyst layer as described above, the crystallinity of the electrolyte membrane can be adjusted by controlling the heating temperature and the pressurizing pressure.

[0215] Example

[0216] The present invention is illustrated by means of examples. However, the present invention is not limited to these examples. The measurement methods used in this embodiment are shown below. It should be noted that in the following measurement methods, when it is difficult to perform the measurement using block copolymers, or when there are concerns about the measurement accuracy, the following electrolyte membrane is used as the test sample instead of block copolymers.

[0217] <Preparation of Electrolyte Membrane (Test Sample)>

[0218] A 25 wt% N-methylpyrrolidone (NMP) solution, prepared by dissolving the block copolymer, was pressure filtered through a glass fiber filter and then cast onto a glass substrate. After drying at 100°C for 4 hours, it was heat-treated at 150°C for 10 minutes under nitrogen to obtain a membrane with a thickness of 10 μm. Next, the membrane was immersed in a 10 wt% sulfuric acid aqueous solution at 95°C for 24 hours to undergo proton displacement and deprotection reactions. Following this, it was immersed in a large excess of pure water for 24 hours for thorough washing and drying to obtain the electrolyte membrane. The crystallinity of this electrolyte membrane (test sample) was 0% as determined by wide-angle X-ray diffraction (XRD).

[0219] (1) Molecular weight of polymer

[0220] The number-average molecular weight and weight-average molecular weight of the polymer were determined using GPC. A Tosoo Corporation HLC-8022GPC was used as an integrated device combining a UV detector and a differential refractometer. A Tosoo Corporation TSKgelGuardColumnSuperH-H (4.6 mm inner diameter, 3.5 cm length) was used as a guard column, and two Tosoo Corporation TSKgelSuperHM-H (6.0 mm inner diameter, 15 cm length) columns were used as GPC columns. The measurements were performed using N-methyl-2-pyrrolidone solvent (N-methyl-2-pyrrolidone solvent containing 10 mmol / L lithium bromide) at a sample concentration of 0.1 wt%, a flow rate of 0.2 mL / min, a temperature of 40 °C, and a measurement wavelength of 265 nm. The number-average molecular weight and weight-average molecular weight were calculated by conversion to standard polystyrene.

[0221] (2) Ion exchange capacity (IEC)

[0222] The determination was performed using the neutralization titration methods described in 1) to 4) below. The determination was performed three times, and the average value was taken.

[0223] 1) Perform proton exchange. After wiping away the moisture from the block copolymer that has been thoroughly washed with pure water, vacuum dry it at 100°C for more than 12 hours and calculate the dry weight.

[0224] 2) Ion exchange was carried out by adding 50 mL of 5 wt% sodium sulfate aqueous solution to the block copolymer and letting it stand for 12 hours.

[0225] 3) The generated sulfuric acid was titrated using a 0.01 mol / L sodium hydroxide aqueous solution. 0.1 w / v% commercially available phenolphthalein titration solution was added as an indicator; the endpoint was reached when the solution turned a light purple-red.

[0226] 4) IEC can be obtained from the following formula.

[0227] IEC (meq / g) = [concentration of sodium hydroxide aqueous solution (mmol / mL) × amount added (mL)] / dry weight of sample (g).

[0228] (3) Determination of glass transition temperature Tg

[0229] Inside the DSC apparatus, after pre-drying 10 mg of electrolyte material at 110 °C for 3 hours, the test sample was heated to 200 °C without being removed from the DSC apparatus under the following conditions, and temperature-modulated differential scanning calorimetry (DSC) analysis was performed during the heating phase. At this point, the glass transition temperature was defined as the midpoint between the two intersections of the two extended lines of the baseline and the tangent to the endothermic curve.

[0230] DSC device: DSC7000X (manufactured by Hitachi Technologies Co., Ltd.)

[0231] Measurement temperature range: 30℃~200℃

[0232] Temperature control: AC temperature control

[0233] Heating rate: 2℃ / min

[0234] Amplitude: ±3℃

[0235] Application frequency: 0.02Hz

[0236] Sample tray: aluminum crucible

[0237] Measurement and pre-drying atmosphere: Nitrogen 100 mL / min

[0238] Pre-drying: 110℃, 3 hours.

[0239] (4) Determination of saturated crystallinity

[0240] The electrolyte membrane (test sample) was cut into 5cm × 5cm squares and sandwiched between two polyimide membranes (50μm thick). The crystallinity was repeatedly measured after heating and pressurizing the sample at 4.5 MPa for 5 minutes at a temperature 5°C above the glass transition temperature of each block copolymer. The crystallinity at which no further change occurred was taken as the saturated crystallinity. The method for determining crystallinity is described below.

[0241] <Determination of Crystallinity by Wide-Angle X-ray Diffraction (XRD)>

[0242] The heated and pressurized test sample was placed in a diffractometer, and X-ray diffraction measurements were performed under the following conditions.

[0243] X-ray diffraction apparatus: RINT2500V manufactured by Rigaku Corporation

[0244] X-rays: Cu-Kα

[0245] X-ray output power: 50kV-300mA

[0246] Optical system: Concentrating optical system

[0247] Scanning speed: 2θ = 2° / min

[0248] Scanning method: 2θ-θ

[0249] Scan range: 2θ = 5–60°

[0250] Slits: Diverging slit -1 / 2°, Receiving slit -0.15mm, Diffusing slit -1 / 2°

[0251] For X-ray diffraction measurements, the components are separated by peak shape fitting, and the diffraction angle and integral intensity of each component are obtained. The crystallinity is calculated using the integral intensities of the obtained crystalline peaks and amorphous halos, according to the following general formula (s2).

[0252] Crystallinity (%) = (sum of the integral intensities of all crystalline peaks) / (sum of the integral intensities of all crystalline peaks and amorphous halos) × 100···(s2).

[0253] (5) Determination of heat of crystallization by differential scanning calorimetry (DSC)

[0254] Inside the DSC apparatus, after pre-drying 10 mg of electrolyte membrane (test sample) at 110 °C for 3 hours, the test sample was heated to 200 °C without being removed from the DSC apparatus under the following conditions, and temperature-modulated differential scanning calorimetry analysis was performed during the heating phase.

[0255] • Measurement temperature range: 30℃~200℃

[0256] • Temperature control: AC temperature control

[0257] • Heating rate: 2℃ / min

[0258] • Amplitude: ±3℃

[0259] • Application frequency: 0.02Hz

[0260] • Sample tray: Aluminum crucible

[0261] • Atmosphere for measurement and pre-drying: Nitrogen 100 mL / min.

[0262] (6) Observation of phase separation structure using transmission electron microscopy (TEM)

[0263] The phase-separated structure was confirmed using an electrolyte membrane (test sample). The sample slide was immersed in a 2% (w / w) aqueous solution of lead acetate as a staining agent and placed at 25°C for 72 hours. The stained sample was then removed and embedded in epoxy resin. Using an ultramicrotome, the slides were cut into 80 nm sections at room temperature, and the resulting sections were transferred to a Cu grid for TEM observation. Observations were performed at an accelerating voltage of 100 kV and magnifications ranging from 10,000 to 100,000 times. It should be noted that the magnifications were appropriately set according to the size of the phase-separated structure. An HT7700 (manufactured by Hitachi Hitec Co., Ltd.) was used as the instrument.

[0264] In addition, a high-speed Fourier transform (FFT) was performed on the TEM image, and the length of the spatial frequencies in the TD and ZD directions was measured from the resulting annular FFT pattern, from which the periodic size of the phase-separated structure was calculated. Regarding the spatial frequencies, the distance from the center of the image to the center of the ring thickness was measured. The FFT and length measurements were performed using DigitalMicrograph (manufactured by Gatan).

[0265] (7) Observe the phase separation structure by transmission electron microscopy (TEM) tomography.

[0266] The thin sheet sample prepared by the method described in (6) above was mounted on a collodion film and observed under the following conditions.

[0267] Apparatus: Field emission electron microscope (HRTEM), JEM 2100F, manufactured by Nippon Electron Ltd.

[0268] Image acquisition: DigitalMicrograph (Gatan)

[0269] System: Notation

[0270] Accelerating voltage: 200kV

[0271] Shooting magnification: 30,000x

[0272] Tilt angle: +60° to -62°

[0273] Reconstruction resolution: 0.71nm / pixel

[0274] The three-dimensional reconstruction process employed a marker method. Au colloidal particles applied to a colloid film were used as alignment markers during the three-dimensional reconstruction. Based on the markers, CT reconstruction was performed within a range of +61° to -62°, using a series of 124 TEM images acquired from a continuous tilting image series taken at 1° angles to the sample, to observe the three-dimensional phase-separated structure.

[0275] (8) Proton conductivity

[0276] An isopropanol-based carbon paste (E-Em Japan Co., Ltd. G7711) was coated onto the platinum electrode of the battery, and a diffusion layer electrode (E-TEK ELAT GDL 140-HT) cut to 18 mm × 6 mm was attached. A rectangular electrolyte membrane (test sample) cut to 30 mm × 8 mm was placed between the electrodes. The battery was then secured at 1 MPa and stored in the chamber of an MTS740. The proton resistance in the thickness direction of the electrolyte membrane was evaluated using an MTS740 membrane resistance measurement system (Scribner). The battery was stored in a temperature-controlled chamber in the MTS740, and air was supplied to the chamber via a humidifier and a mass flow controller. A frequency response analyzer PSM1735 (Newtons4th) was connected to the battery, and an AC signal was scanned from 1 MHz to 1 kHz to determine the resistance.

[0277] The MTS740 and PSM1735 can be connected to a personal computer and controlled via software. After setting the chamber temperature to 80°C, 90% RH air was supplied and maintained for 1 hour to fully wet the electrolyte membrane. Then, 20% RH air was supplied to dry it, followed by 30% RH air for 30 minutes, during which the resistance was measured. The frequency was scanned from 1MHz to 1kHz. Then, 80% RH air was supplied and maintained for 30 minutes, and the resistance was measured again. A Cole-Cole plot was constructed based on the measured resistance data. The frequency band near 1MHz is affected by the inductive component of the cable connecting the battery to the PSM1735; therefore, the real axis value at 200kHz, where its influence is minimal, was used as the resistance value (Ω). The proton conductivity with 30% RH air supplied was taken as the low humidified proton conductivity, and the proton conductivity with 80% RH air supplied was taken as the high humidified proton conductivity. Using the measured resistance values, the proton conductivity was calculated using the following formula.

[0278] Proton conductivity (mS / cm) = 1 / (resistance (Ω) × active area (cm²) 2 () / sample thickness (cm)).

[0279] The low humidification proton conductivity is preferably 0.85 mS / cm or higher, more preferably 0.90 mS / cm or higher, even more preferably 1.00 mS / cm or higher, and particularly preferably 1.10 mS / cm or higher. The high humidification proton conductivity is preferably 9.00 mS / cm or higher, more preferably 9.50 mS / cm or higher, even more preferably 11.00 mS / cm or higher, and particularly preferably 13.00 mS / cm or higher.

[0280] (9) Dry and wet dimensional change rate

[0281] The electrolyte membrane (test sample) was cut into rectangles of 3mm × 20mm to serve as sample pieces. These sample pieces were placed in the sample holder of a TMA / SS6100 thermomechanical analysis apparatus (manufactured by Hitachi High Tech Systems Co., Ltd.) equipped with a furnace featuring temperature and humidity control, with the long side of the sample piece facing the measurement direction, and were set to apply a stress of 20mN. Inside the furnace, the sample was stabilized at 23°C and 50% RH for 1 hour, and the length of the sample piece was set to zero. The furnace temperature was fixed at 23°C, and after 30 minutes, the humidity was adjusted to 30% RH (drying condition) and maintained for 20 minutes. Next, the humidity was adjusted to 90% RH (humidifying condition) for 30 minutes. This dry-wet cycle (30% RH - 90% RH) was considered one cycle, and the difference between the dimensional change rate (%) at 30% RH and the dimensional change rate (%) at 90% RH in the 10th cycle was taken as the dry-wet dimensional change rate (%). The wet-dry dimensional change rate is preferably 7.0% or less, more preferably 6.5% or less, even more preferably 6.0% or less, and particularly preferably 5.7% or less.

[0282] [Polymer Synthesis]

[0283] The structures of the compounds obtained in the following synthetic examples are obtained by means of... 1 The results were confirmed by 1H-NMR. Purity was quantitatively analyzed by capillary electrophoresis (organic matter) and ion chromatography (inorganic matter).

[0284] <Synthesis example 1>

[0285] (Synthesis of 2,2-bis(4-hydroxyphenyl)-1,3-dioxane (K-DHBP) represented by the following formula (G1))

[0286] A solution was prepared by adding 49.5 g of 4,4'-dihydroxybenzophenone, 134 g of ethylene glycol, 96.9 g of trimethyl orthoformate, and 0.50 g of p-toluenesulfonic acid monohydrate to a 500 mL flask equipped with a stirrer, thermometer, and fractionating tube. The solution was then stirred and kept at 78–82 °C for 2 hours. The internal temperature was then slowly increased to 120 °C and maintained at 120 °C until the fractionation of methyl formate, methanol, and trimethyl orthoformate completely ceased. After cooling the reaction solution to room temperature, it was diluted with ethyl acetate. The organic layer was washed with 100 mL of 5% potassium carbonate aqueous solution and separated, and the solvent was removed by distillation. 80 mL of dichloromethane was added to the residue to induce crystallization. The crystals were filtered and dried to obtain 52.0 g of 2,2-bis(4-hydroxyphenyl)-1,3-dioxane with a purity of 99.9%.

[0287]

[0288] <Synthesis example 2>

[0289] (The following formula (G2) represents the synthesis of 3,3'-disulfonated-4,4'-difluorobenzophenone disodium salt)

[0290] 109.1 g of 4,4'-difluorobenzophenone (Artrich reagent) was reacted at 100°C for 10 hours in 150 mL of fuming sulfuric acid (50% SO3) (Wako Pure Chemical Reagent). Then, the product was gradually added to a large volume of water, neutralized with NaOH, and then 200 g of sodium chloride (NaCl) was added to precipitate the product. The precipitate was filtered and recrystallized from an aqueous ethanol solution to obtain disodium 3,3'-disulfonated-4,4'-difluorobenzophenone. The purity was 99.3%.

[0291]

[0292] <Synthesis Example 3>

[0293] (The following formula (G3) represents the synthesis of disodium 3,3'-disulfonic-4,4'-difluorodiphenyl sulfone)

[0294] 109.1 g of 4,4-difluorodiphenyl sulfone (Artrich reagent) was reacted at 100°C for 10 hours in 150 mL of fuming sulfuric acid (50% SO3). Then, the product was gradually added to a large volume of water, neutralized with NaOH, and then 200 g of sodium chloride was added to precipitate the product. The precipitate was filtered and recrystallized from an aqueous ethanol solution to obtain disodium 3,3'-disulfonic acid-4,4'-difluorodiphenyl sulfone. The purity was 99.3%.

[0295]

[0296] [Electrolyte Materials (I)]

[0297] [Example 1]

[0298] <Synthesis of nonionic oligomer a1 represented by the following general formula (G4)>

[0299] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 16.59 g of potassium carbonate (artrich reagent, 120 mmol), 25.83 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, and 21.38 g (artrich reagent, 98 mmol) of 4,4'-difluorobenzophenone. After nitrogen purging of the apparatus, 300 mL of N-methylpyrrolidone (NMP) and 100 mL of toluene were added. Dehydration was carried out at 150 °C, followed by heating to remove toluene, and polymerization was performed at 170 °C for 3 hours. Reprecipitation purification was carried out in a large amount of methanol to obtain the terminal hydroxyl body of the nonionic oligomer a1. The number average molecular weight of the terminal hydroxyl body of the nonionic oligomer a1 was 20,000.

[0300] 1.1 g of potassium carbonate (artrich reagent, 8 mmol) and 20.0 g (1 mmol) of the terminal hydroxyl group of the above-mentioned nonionic oligomer a1 were added to a 500 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark separator. After nitrogen purging of the apparatus, 100 mL of NMP and 30 mL of toluene were added, and dehydration was carried out at 100 °C, followed by heating to remove the toluene. 1.1 g of hexafluorobenzene (artrich reagent, 6 mmol) was then added, and the reaction was carried out at 105 °C for 12 hours. Purification was achieved by redeposition with a large amount of isopropanol to obtain the nonionic oligomer a1 (terminal: fluorine group) represented by the following general formula (G4). The number average molecular weight of this nonionic oligomer a1 is 21,000. It should be noted that in general formula (G4), m represents an integer greater than or equal to 1.

[0301]

[0302] <Synthesis of ionic oligomer a2 represented by the following general formula (G5)>

[0303] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 27.64 g of potassium carbonate (Artrich reagent, 200 mmol), 12.91 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.31 g (Artrich reagent, 50 mmol) of 4,4'-biphenol, 41.60 g (98.5 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 26.40 g (Wako Purity, 100 mmol) of 18-crown-6-ether. After nitrogen purging, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 150 °C, followed by heating to remove the toluene. Polymerization was then carried out at 170 °C for 6 hours. Purification was achieved by reprecipitation with a large amount of isopropanol, yielding the ionic oligomer a2 (terminal: OM group) represented by the following general formula (G5). The number-average molecular weight of this ionic oligomer a2 is 45,000. It should be noted that in general formula (G5), M represents a hydrogen atom, Na, or K, and n represents an integer greater than or equal to 1.

[0304]

[0305] <Synthesis of ionic oligomer a2' represented by the following general formula (G6)>

[0306] 0.56 g of potassium carbonate (Aldrich reagent, 400 mmol) and 49.0 g of ionic oligomer a2 were charged into a 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging of the apparatus, 500 mL of NMP was added, and the contents were dissolved at 60 °C. Then, 19.8 g of hexafluorobenzene / NMP solution (1 wt%) was added. The reaction was carried out at 80 °C for 18 hours to obtain an NMP solution containing ionic oligomer a2' (terminal: OM group) represented by general formula (G6). The number average molecular weight of this ionic oligomer a2' is 90,000. It should be noted that in general formula (G6), M represents a hydrogen atom, Na or K, and n represents an integer greater than or equal to 1.

[0307]

[0308] <Synthesis of Block Copolymer b1>

[0309] The block copolymer b1 contains the aforementioned oligomer a2' as an ionic segment and the aforementioned oligomer a1 as a nonionic segment.

[0310] 49.0 g of ionic oligomer a2 and 7.65 g of nonionic oligomer a1 were charged into a 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. NMP was added at a total oligomer input of 7 wt%, and the reaction was carried out at 105 °C for 24 hours. Reprecipitation was performed in a large volume of isopropanol / NMP mixture (weight ratio 2 / 1), followed by purification with a large volume of isopropanol to obtain block copolymer b1. The number average molecular weight of block copolymer b1 was 170,000, and the weight average molecular weight was 410,000.

[0311] The block copolymer b1 has a saturated crystallinity of 11.6%, a glass transition temperature of 157 °C, and an IEC of 2.5 meq / g. Electrolyte membranes made using block copolymer b1 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0312] [Example 2]

[0313] <Synthesis of Block Copolymer b2>

[0314] The block copolymer b2 contains the aforementioned oligomer a2' as an ionic segment and the aforementioned oligomer a1 as a nonionic segment.

[0315] Using 5.4 g of nonionic oligomer a1, the block copolymer b2 was obtained by proceeding in the same manner as in Example 1. The number average molecular weight of the block copolymer b2 was 180,000, and the weight average molecular weight was 430,000.

[0316] The block copolymer b2 has a saturated crystallinity of 9.2%, a glass transition temperature of 160 °C, and an IEC of 2.7 meq / g. Electrolyte membranes made using block copolymer b2 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0317] [Example 3]

[0318] (Synthesis of nonionic oligomer a3 represented by the above general formula (G4))

[0319] Using 21.45 g of 4,4'-difluorobenzophenone, the same procedure as for the synthesis of the terminal hydroxyl body of oligomer a1 was followed to obtain the terminal hydroxyl body of oligomer a3. The number average molecular weight of the terminal hydroxyl body of oligomer a3 was 25,000.

[0320] Using 25.0 g of the terminal hydroxyl group of oligomer a3 instead of the terminal hydroxyl group of oligomer a1, the synthesis of oligomer a1 was performed in the same manner as that of oligomer a1 to obtain nonionic oligomer a3 (terminal: fluorine group) represented by general formula (G4). The number average molecular weight of this nonionic oligomer a3 is 26,000.

[0321] <Synthesis of Block Copolymer b3>

[0322] The block copolymer b3 contains the aforementioned oligomer a2' as an ionic segment and the aforementioned oligomer a3 as a nonionic segment.

[0323] Using nonionic oligomer a3 (12.3 g) instead of nonionic oligomer a1 (7.65 g), the same procedure as for the synthesis of block copolymer b1 was followed to obtain block copolymer b3. The number-average molecular weight of block copolymer b3 was 160,000, and the weight-average molecular weight was 390,000.

[0324] The block copolymer b3 has a saturated crystallinity of 15.6%, a glass transition temperature of 160 °C, and an IEC of 2.1 meq / g. Electrolyte membranes made using block copolymer b3 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0325] [Example 4]

[0326] <Synthesis of nonionic oligomer a5 represented by the above general formula (G4)>

[0327] Using 21.51 g of 4,4'-difluorobenzophenone, the synthesis of the terminal hydroxyl body of oligomer a5 was carried out in the same manner as that of oligomer a1. The number average molecular weight of the terminal hydroxyl body of oligomer a5 was 29,000.

[0328] Using 29.0 g of the terminal hydroxyl group of oligomer a5 instead of the terminal hydroxyl group of oligomer a1, the synthesis of oligomer a1 was performed in the same manner as that of oligomer a1 to obtain nonionic oligomer a5 (terminal: fluorine group) represented by general formula (G4). The number average molecular weight of this nonionic oligomer a5 is 30,000.

[0329] <Synthesis of ionic oligomer a4 represented by the above general formula (G5)>

[0330] The amount of 41.38 g (98.0 mmol) of disodium 3,3'-disulfonic acid-4,4'-difluorobenzophenone was used, and the process was otherwise performed in the same manner as the synthesis of ionic oligomer a2 to obtain ionic oligomer a4. The number average molecular weight of ionic oligomer a4 is 35,000.

[0331] <Synthesis of the ionic oligomer a4' represented by the following general formula (G7)>

[0332] 0.56 g of potassium carbonate (Aldrich reagent, 400 mmol) and 37.16 g of ionic oligomer a4 were charged into a 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging of the apparatus, 400 mL of NMP was added, and the contents were dissolved at 60 °C. Then, 11.4 g of 2,6-difluorobenzonitrile / NMP solution (1 wt%) was added. The reaction was carried out at 80 °C for 18 hours to obtain an NMP solution containing ionic oligomer a4' (terminal: OM group) represented by general formula (G7). The number average molecular weight of this ionic oligomer a4' is 70,000. It should be noted that in general formula (G7), M represents a hydrogen atom, Na or K, and n represents an integer greater than or equal to 1.

[0333]

[0334] <Synthesis of Block Copolymer b4>

[0335] The block copolymer b4 contains the aforementioned oligomer a4' as an ionic segment and the aforementioned oligomer a5 as a nonionic segment.

[0336] Ionic oligomer a4' (37.16 g) was used in place of ionic oligomer a2' (49.0 g), and nonionic oligomer a5 (12.39 g) was used in place of nonionic oligomer a1 (7.65 g). Otherwise, the synthesis of block copolymer b1 was carried out in the same manner to obtain block copolymer b4. The number-average molecular weight of block copolymer b4 is 120,000, and the weight-average molecular weight is 360,000.

[0337] The block copolymer b4 has a saturated crystallinity of 18.0%, a glass transition temperature of 160 °C, and an IEC of 1.9 meq / g. Electrolyte membranes made using block copolymer b4 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0338] [Example 5]

[0339] <Synthesis of nonionic oligomer a7 represented by the above general formula (G4)>

[0340] Using 21.27 g of 4,4'-difluorobenzophenone, the same procedure as for the synthesis of the terminal hydroxyl body of nonionic oligomer a1 was followed to obtain the terminal hydroxyl body of nonionic oligomer a7. The number average molecular weight of the terminal hydroxyl body of nonionic oligomer a7 was 16000.

[0341] The terminal hydroxyl group of nonionic oligomer a7 (16.0 g) was used instead of the terminal hydroxyl group of nonionic oligomer a1 (20.0 g), and the synthesis of nonionic oligomer a1 was carried out in the same manner as that of nonionic oligomer a1 to obtain nonionic oligomer a7 (terminal: fluorine group) represented by general formula (G4). The number average molecular weight of nonionic oligomer a7 is 17000.

[0342] <Synthesis of ionic oligomer a6 represented by the above general formula (G5)>

[0343] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 27.64 g of potassium carbonate (artrich reagent, 200 mmol), 12.91 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.31 g (artrich reagent, 50 mmol) of 4,4'-biphenol, and 41.85 g (99.1 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2. After nitrogen purging of the apparatus, 300 mL of dimethyl sulfoxide (DMSO) and 100 mL of toluene were added. After dehydration at 133 °C, the toluene was removed by heating. Polymerization was carried out at 150 °C for 2 hours, and then further polymerized at 155 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain ionic oligomer a6 (terminal: OM group) represented by general formula (G5). The number average molecular weight of ionic oligomer a6 is 56,000.

[0344] <Synthesis of Block Copolymer b5>

[0345] Block copolymer b5 contains the aforementioned oligomer a6 as an ionic segment and the aforementioned oligomer a7 as a nonionic segment.

[0346] Ionic oligomer a6 (32.79 g) was used instead of ionic oligomer a2' (49.0 g), and nonionic oligomer a7 (8.19 g) was used instead of nonionic oligomer a1 (7.65 g). Otherwise, the synthesis was carried out in the same manner as that of block copolymer b1 to obtain block copolymer b5. The number-average molecular weight of block copolymer b5 is 140,000, and the weight-average molecular weight is 360,000.

[0347] The block copolymer b5 has a saturated crystallinity of 13.5%, a glass transition temperature of 159 °C, and an IEC of 2.1 meq / g. Electrolyte membranes made using block copolymer b5 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0348] [Comparative Example 1]

[0349] <Synthesis of nonionic oligomer a9 represented by the above general formula (G4)>

[0350] Using 20.4 g of 4,4'-difluorobenzophenone, the same procedure as for the synthesis of the terminal hydroxyl body of nonionic oligomer a1 was followed to obtain the terminal hydroxyl body of nonionic oligomer a9. The number average molecular weight of the terminal hydroxyl body of nonionic oligomer a9 was 7000.

[0351] The terminal hydroxyl group of nonionic oligomer a9 (9.0 g: 1 mmol) was used instead of the terminal hydroxyl group of nonionic oligomer a1 (20.0 g), and the synthesis of nonionic oligomer a1 was carried out in the same manner as that of nonionic oligomer a1 to obtain nonionic oligomer a9 (terminal: fluorine group) represented by general formula (G4). The number average molecular weight of nonionic oligomer a9 is 8000.

[0352] <Synthesis of ionic oligomer a8 represented by the above general formula (G5)>

[0353] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 27.64 g of potassium carbonate (Artrich reagent, 200 mmol), 12.91 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.31 g (Artrich reagent, 50 mmol) of 4,4'-biphenol, 41.47 g (98.2 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 26.40 g (Wako Purified Chemicals, 100 mmol) of 18-crown-6-ether. After nitrogen purging, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 150 °C, followed by heating to remove the toluene. Polymerization was then carried out at 170 °C for 6 hours. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain ionic oligomer a8 (terminal: hydroxyl) represented by general formula (G5). The number average molecular weight of ionic oligomer a8 is 42,000.

[0354] <Synthesis of Block Copolymer b6>

[0355] Block copolymer b6 contains oligomer a8 as an ionic segment and oligomer a9 as a nonionic segment.

[0356] Ionic oligomer a8 (43.57 g) was used instead of ionic oligomer a2' (49.0 g), and nonionic oligomer a9 (10.89 g) was used instead of nonionic oligomer a1 (7.65 g). Otherwise, the synthesis was carried out in the same manner as that of block copolymer b1 to obtain block copolymer b6. The number-average molecular weight of block copolymer b6 is 140,000, and the weight-average molecular weight is 400,000.

[0357] The block copolymer b6 has a saturated crystallinity of 4.1%, a glass transition temperature of 157 °C, and an IEC of 2.2 meq / g. Electrolyte membranes made using block copolymer b6 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0358] [Comparative Example 2]

[0359] (Synthesis of the nonionic oligomer a11 represented by the above general formula (G4))

[0360] Using 20.18 g of 4,4'-difluorobenzophenone, the synthesis of the terminal hydroxyl body of nonionic oligomer a1 was carried out in the same manner as that for nonionic oligomer a1, to obtain the terminal hydroxyl body of nonionic oligomer a11. The number average molecular weight of the terminal hydroxyl body of nonionic oligomer a11 was 5000.

[0361] 2.2 g of potassium carbonate (artrich reagent, 16 mmol) and 10.0 g of the terminal hydroxyl group of nonionic oligomer a11 were added to a 500 mL three-necked flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging, 100 mL of NMP and 30 mL of toluene were added. Dehydration was carried out at 100 °C, followed by heating to remove the toluene. 2.2 g of hexafluorobenzene (artrich reagent, 12 mmol) was then added, and the reaction was carried out at 105 °C for 12 hours. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain nonionic oligomer a11 (terminal: fluorine group) represented by general formula (G4). The number average molecular weight of nonionic oligomer a11 is 6000.

[0362] <Synthesis of Block Copolymer b7>

[0363] The block copolymer b7 contains the aforementioned oligomer a8 as an ionic segment and the aforementioned oligomer a11 as a nonionic segment.

[0364] Using nonionic oligomer a11 (6.81 g) instead of nonionic oligomer a9 (10.89 g), the same procedure as for the synthesis of block copolymer b6 was followed to obtain block copolymer b7. The number-average molecular weight of block copolymer b7 was 130,000, and the weight-average molecular weight was 400,000.

[0365] The block copolymer b7 has a saturated crystallinity of 0.8%, a glass transition temperature of 157 °C, and an IEC of 2.4 meq / g. Electrolyte membranes made using block copolymer b7 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase), but some discontinuous structures were observed.

[0366] [Comparative Example 3]

[0367] <Synthesis of nonionic oligomer a13 represented by the following general formula (G8)>

[0368] Using 23.65 g of 4,4'-difluorodiphenyl sulfone instead of 4,4'-difluorobenzophenone, the same procedure as for the synthesis of the terminal hydroxyl body of nonionic oligomer a1 was followed to obtain the terminal hydroxyl body of nonionic oligomer a13. The number average molecular weight of the terminal hydroxyl body of nonionic oligomer a13 was 10,000.

[0369] Using 10.0 g of the terminal hydroxyl group of nonionic oligomer a13 instead of 20.0 g of the terminal hydroxyl group of nonionic oligomer a1, the synthesis of nonionic oligomer a1 was carried out in the same manner as that of nonionic oligomer a1, to obtain nonionic oligomer a13 (terminal: fluorine group) represented by general formula (G8). The number average molecular weight of this nonionic oligomer a13 is 11000. It should be noted that in general formula (G8), m represents an integer greater than 1.

[0370]

[0371] <Synthesis of ionic oligomer a12 represented by the following general formula (G9)>

[0372] Using 44.94 g (98.1 mmol) of disodium 3,3'-disulfonic-4,4'-difluorodiphenyl sulfone obtained in Synthesis Example 3 instead of 41.60 g of disodium 3,3'-disulfonic-4,4'-difluorobenzophenone, the synthesis of ionic oligomer a2 was carried out in the same manner as that of ionic oligomer a2, to obtain ionic oligomer a12 (terminal: OM group) represented by general formula (G9). The number average molecular weight of ionic oligomer a12 is 41,000. It should be noted that in general formula (G9), M represents a hydrogen atom, Na or K, and n represents an integer greater than or equal to 1.

[0373]

[0374] <Synthesis of Block Copolymer B8>

[0375] The block copolymer b8 contains the aforementioned oligomer a12 as an ionic segment and the aforementioned oligomer a13 as a nonionic segment.

[0376] Ionic oligomer a12 (45.76 g) and nonionic oligomer a13 (8.93 g) were charged into a 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. NMP was added at a total oligomer input of 7 wt%, and the reaction was carried out at 105 °C for 24 hours. Reprecipitation was performed in a large volume of isopropanol / NMP mixture (2 / 1 by weight), followed by purification with a large volume of isopropanol to obtain block copolymer b8. The number average molecular weight of block copolymer b8 was 120,000, and the weight average molecular weight was 290,000.

[0377] The block copolymer b8 has a saturated crystallinity of 0.0%, a glass transition temperature of 231 °C, and an IEC of 2.4 meq / g. Electrolyte membranes made using block copolymer b8 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase).

[0378] [Measurement Results]

[0379] The measurement results of the electrolyte materials obtained in Examples 1 to 5 and Comparative Examples 1 to 3, as well as the evaluation results of proton conductivity and dry-wet dimensional change rate, are shown in Table 1.

[0380] [Table 1]

[0381]

[0382] In Examples 1-5, an electrolyte material (I) with a saturated crystallinity of 5% or more and 30% or less was used, resulting in a small dry-wet dimensional change rate and high proton conductivity under both low and high humidification conditions. In other words, mechanical durability and proton conductivity were achieved simultaneously at a high level.

[0383] On the other hand, the saturated crystallinity of Comparative Examples 1 to 3 was all below 5%. As a result, the dry-wet dimensional change rate or proton conductivity was poor. That is, mechanical durability and proton conductivity were not achieved simultaneously.

[0384] [Examples 11-15]

[0385] Electrolyte membranes (test samples) made from the electrolyte materials of Examples 1-5 were heated and pressurized to a "crystallization degree of 0%" under the conditions where the crystallinity no longer changed in "(4) Determination of saturated crystallinity" above. The resulting products were used as samples, and the dry and wet dimensional change rate and proton conductivity were measured. The results are shown in Table 2.

[0386] [Table 2]

[0387] Table 2

[0388]

[0389] Electrolyte membranes (test samples) made from the electrolyte material (I) of the present invention, as shown in Examples 1 to 5 of Table 1, simultaneously achieve high levels of mechanical durability (dry-wet dimensional change rate) and proton conductivity even without crystallization (even if the crystallinity is 0%). However, by crystallization, as shown in Table 2, mechanical durability (dry-wet dimensional change rate) and proton conductivity are further improved.

[0390] [Electrolyte Materials (II)]

[0391] [Example 21]

[0392] <Block copolymer b21>

[0393] As block copolymer b21, the aforementioned block copolymer b1 was used. For the aforementioned block copolymer b21, a crystallization peak was observed by DSC, and the heat of crystallization was 15.8 J / g. Therefore, the product of IEC and heat of crystallization is 39.5.

[0394] [Example 22]

[0395] <Block copolymer b22>

[0396] As block copolymer b22, the aforementioned block copolymer b2 was used. For the aforementioned block copolymer b22, a crystallization peak was observed by DSC, and the heat of crystallization was 13.2 J / g. Therefore, the product of IEC and heat of crystallization is 35.6.

[0397] [Example 23]

[0398] <Synthesis of the ionic oligomer a24 represented by the above general formula (G5)>

[0399] The amount of 41.38 g (98.0 mmol) of disodium 3,3'-disulfonic acid-4,4'-difluorobenzophenone was used, and the process was otherwise performed in the same manner as the synthesis of ionic oligomer a2 to obtain ionic oligomer a24. The number average molecular weight of ionic oligomer a24 is 35,000.

[0400] <Synthesis of the ionic oligomer a24' represented by the above general formula (G6)>

[0401] Ionic oligomer a24 (37.16 g) was used instead of ionic oligomer a2 (49.0 g), the amount of NMP used was 400 mL, and the amount of hexafluorobenzene / NMP solution (1 wt%) was 15.3 g. Otherwise, the process was the same as that used in the synthesis of ionic oligomer a2', to obtain an NMP solution containing ionic oligomer a24' (terminal: OM group) represented by general formula (G6). The number average molecular weight of oligomer a24' is 70,000.

[0402] <Synthesis of Block Copolymer b23>

[0403] The block copolymer b23 contains the aforementioned oligomer a24' as an ionic segment and the aforementioned oligomer a1 as a nonionic segment.

[0404] In a 2000 mL SUS polymerization apparatus equipped with a mixer, nitrogen inlet tube, and Dean-Stark separator, ionic oligomer a24' (37.16 g) was used instead of ionic oligomer a2' (49.0 g), and the amount of nonionic oligomer a1 used was 5.80 g. Otherwise, the synthesis was carried out in the same manner as that of block copolymer b1 to obtain block copolymer b23. The number-average molecular weight of block copolymer b23 was 190,000, and the weight-average molecular weight was 440,000.

[0405] The IEC of the aforementioned block copolymer b23 is 2.4 meq / g. Electrolyte membranes made using the aforementioned block copolymer b23 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 16.6 J / g. Therefore, the product of IEC and heat of crystallization is 39.8.

[0406] [Example 24]

[0407] <Synthesis of nonionic oligomer a21 represented by the following general formula (G10)>

[0408] 1.1 g of potassium carbonate (artrich reagent, 8 mmol) and 20.0 g (1 mmol) of the terminal hydroxyl group of nonionic oligomer a1 were added to a 500 mL three-necked flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging, 100 mL of NMP and 30 mL of toluene were added, and dehydration was carried out at 100 °C, followed by heating to remove the toluene. Then, 0.84 g of 2,6-difluorobenzonitrile (artrich reagent, 6 mmol) was added, and the reaction was carried out at 105 °C for 12 hours. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain nonionic oligomer a21 (terminal: fluorine group) represented by the following general formula (G10). The number average molecular weight of nonionic oligomer a21 is 21,000. It should be noted that in general formula (G10), m represents an integer greater than or equal to 1.

[0409]

[0410] <Synthesis of the ionic oligomer a24 represented by the following general formula (G11)>

[0411] 0.56 g of potassium carbonate (Aldrich reagent, 400 mmol) and 37.16 g of ionic oligomer a24 were charged into a 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging of the apparatus, 400 mL of NMP was added, and the contents were dissolved at 60 °C. Then, 11.4 g of 2,6-difluorobenzonitrile / NMP solution (1 wt%) was added. The reaction was carried out at 80 °C for 18 hours to obtain an NMP solution containing ionic oligomer a24 (terminal: OM group) represented by general formula (G11). The number average molecular weight of this ionic oligomer a24” is 70,000. It should be noted that in general formula (G11), M represents a hydrogen atom, Na or K, and n represents an integer greater than or equal to 1.

[0412]

[0413] <Synthesis of Block Copolymer b24>

[0414] The block copolymer b24 contains the aforementioned oligomer a24” as an ionic segment and the aforementioned oligomer a21 as a nonionic segment.

[0415] Ionic oligomer a24 (37.16 g) was used instead of ionic oligomer a2' (49.0 g), and the amount of nonionic oligomer a21 used was 5.80 g. Otherwise, the same procedure as for the synthesis of block copolymer b1 was followed to obtain block copolymer b24. The number average molecular weight of block copolymer b24 was 100,000, and the weight average molecular weight was 260,000.

[0416] The IEC of the aforementioned block copolymer b24 is 2.2 meq / g. Electrolyte membranes made using the aforementioned block copolymer b24 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 20.1 J / g. Therefore, the product of IEC and heat of crystallization is 44.2.

[0417] [Example 25]

[0418] <Synthesis of Block Copolymer B25>

[0419] The block copolymer b25 contains the aforementioned oligomer a24” as an ionic segment and the aforementioned oligomer a1 as a nonionic segment.

[0420] Using nonionic oligomer a1 (9.29 g) instead of nonionic oligomer a21 (5.80 g), the same procedure as for the synthesis of block copolymer b24 was followed to obtain block copolymer b25. The number-average molecular weight of block copolymer b25 was 150,000, and the weight-average molecular weight was 380,000.

[0421] The IEC of the aforementioned block copolymer b25 is 2.1 meq / g. Electrolyte membranes made using the aforementioned block copolymer b25 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 22.0 J / g. Therefore, the product of IEC and heat of crystallization is 46.2.

[0422] [Example 26]

[0423] <Block copolymer b26>

[0424] As block copolymer b26, the aforementioned block copolymer b5 was used. For the aforementioned block copolymer b26, a crystallization peak was observed by DSC, and the heat of crystallization was 21.1 J / g. Therefore, the product of IEC and heat of crystallization is 44.3.

[0425] [Example 27]

[0426] <Synthesis of Block Copolymer B27>

[0427] The block copolymer b27 contains the aforementioned oligomer a2' as an ionic segment and the aforementioned oligomer a1 as a nonionic segment.

[0428] Using 4.1 g of nonionic oligomer a1, the procedure was the same as in Example 1 to obtain block copolymer b27. The number-average molecular weight of block copolymer b27 was 160,000, and the weight-average molecular weight was 410,000.

[0429] The IEC of the aforementioned block copolymer b27 is 2.9 meq / g. Electrolyte membranes made using the aforementioned block copolymer b27 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 12.1 J / g. Therefore, the product of IEC and heat of crystallization is 35.1.

[0430] [Comparative Example 21]

[0431] <Synthesis of nonionic oligomer a31 represented by the following general formula (G12)>

[0432] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 16.59 g of potassium carbonate (artrich reagent, 120 mmol), 25.8 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, and 20.3 g of 4,4'-difluorobenzophenone (artrich reagent, 93 mmol). After nitrogen purging, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 160 °C, followed by heating to remove the toluene. Polymerization was then performed at 180 °C for 1 hour. Reprecipitation purification was carried out in a large amount of methanol to obtain the terminal hydroxyl body of the nonionic oligomer a31. The number average molecular weight of the terminal hydroxyl body of the nonionic oligomer a31 was 10,000.

[0433] 1.1 g of potassium carbonate (artrich reagent, 8 mmol) and 20.0 g (2 mmol) of the terminal hydroxyl group of nonionic oligomer a31 were added to a 500 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark separator. After nitrogen purging, 100 mL of NMP and 30 mL of cyclohexane were added. Dehydration was carried out at 100 °C, followed by heating to remove the cyclohexane. 4.0 g of decafluorobiphenyl (artrich reagent, 12 mmol) was then added, and the reaction was carried out at 105 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain nonionic oligomer a31 (terminal: fluorine group) represented by the following general formula (G12). The number average molecular weight of this nonionic oligomer a31 is 11000. It should be noted that in general formula (G12), m represents an integer greater than or equal to 1.

[0434]

[0435] <Synthesis of the ionic oligomer a32 represented by the above general formula (G5)>

[0436] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 27.6 g of potassium carbonate (Artrich reagent, 200 mmol), 12.9 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.3 g (Artrich reagent, 50 mmol) of 4,4'-biphenol, 39.3 g (93 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 17.9 g (Wako Pure Chemicals, 82 mmol). After nitrogen purging of the apparatus, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 170 °C, followed by heating to remove the toluene. Polymerization was then carried out at 180 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of isopropanol, yielding the ionic oligomer a22 (terminal: OM group) represented by the above general formula (G5). The number average molecular weight of this ionic oligomer a32 is 16000.

[0437] <Synthesis of Block Copolymer b31>

[0438] The block copolymer b31 contains the aforementioned oligomer a32 as an ionic segment and the aforementioned oligomer a31 as a nonionic segment.

[0439] 0.56 g of potassium carbonate (Aldrich reagent, 4 mmol) and 16 g (1 mmol) of ionic oligomer a32 were added to a 500 mL three-necked flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging, 100 mL of NMP and 30 mL of cyclohexane were added. Dehydration was carried out at 100 °C, followed by heating to remove the cyclohexane. 11 g (1 mmol) of nonionic oligomer a31 was then added, and the reaction was carried out at 105 °C for 24 hours. The block copolymer b31 was obtained by reprecipitation purification in a large amount of isopropanol. The number average molecular weight of block copolymer b31 was 150,000, and the weight average molecular weight was 340,000.

[0440] The IEC of the aforementioned block copolymer b31 is 1.7 meq / g. Electrolyte membranes made using the aforementioned block copolymer b31 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 22.5 J / g. Therefore, the product of IEC and heat of crystallization is 38.3.

[0441] [Comparative Example 22]

[0442] <Synthesis of nonionic oligomer a33 represented by the following general formula (G13)>

[0443] In the synthesis of nonionic oligomer 31 in Comparative Example 21, 18.62 g of 4,4'-biphenol (Aldrich reagent, 100 mmol) was used instead of 25.8 g (100 mmol) of K-DHBP, and the amount of 4,4'-difluorobenzophenone was changed to 21.41 g. Otherwise, the terminal hydroxyl bodies of nonionic oligomer a33 were synthesized using the same method as in Comparative Example 21. The number average molecular weight was 22,000.

[0444] In addition, 50.0 g (2 mmol) of the terminal hydroxyl group of nonionic oligomer a33 was added to replace the terminal hydroxyl group of nonionic oligomer a31. Otherwise, the synthesis of nonionic oligomer a33 (terminal: fluorine group) was carried out by the same method as Comparative Example 21. The number average molecular weight was 23000.

[0445] It should be noted that in the general formula (G13), m represents an integer greater than or equal to 1.

[0446]

[0447] <Synthesis of the ionic oligomer a34 represented by the above general formula (G5)>

[0448] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 27.6 g of potassium carbonate (Aldrich reagent, 200 mmol), 25.8 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, 41.4 g (98.1 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 17.9 g of 18-crown-6-ether (Wako Purified Chemicals, 82 mmol). After nitrogen purging, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 170 °C, followed by heating to remove the toluene. Polymerization was then carried out at 180 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain the ionic oligomer a34 (terminal: OM group) represented by the above general formula (G5). The number-average molecular weight of the ionic oligomer a34 is 28,000.

[0449] <Synthesis of Block Copolymer b32>

[0450] Block copolymer b32 contains the aforementioned oligomer a34 as an ionic segment and the aforementioned oligomer a33 as a nonionic segment.

[0451] 26 g (1 mmol) of ionic oligomer a34 was added to replace ionic oligomer a32, and 21 g (1 mmol) of nonionic oligomer a33 was added to replace nonionic oligomer a31. Otherwise, block copolymer b32 was obtained by the same method as in Comparative Example 21. The number average molecular weight of this block copolymer b32 was 110,000, and the weight average molecular weight was 380,000.

[0452] The IEC of the aforementioned block copolymer b32 is 1.9 meq / g. Electrolyte membranes made using the aforementioned block copolymer b32 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 25.3 J / g. Therefore, the product of IEC and heat of crystallization is 48.1.

[0453] [Comparative Example 23]

[0454] <Synthesis of the ionic oligomer a36 represented by the above general formula (G5)>

[0455] The amount of 3,3'-disulfonic acid-4,4'-difluorobenzophenone disodium salt was changed to 40.1 g (95 mmol), and the ionic oligomer a36 (terminal: OM group) was obtained by the same method as in Comparative Example 21. The number average molecular weight of this ionic oligomer a36 was 21,000.

[0456] <Synthesis of Block Copolymer b33>

[0457] The block copolymer b33 contains the aforementioned oligomer a36 as an ionic segment and the aforementioned oligomer a31 as a nonionic segment.

[0458] 21 g (1 mmol) of ionic oligomer a36 was added instead of ionic oligomer a32, and block copolymer b33 was obtained by the same method as in Comparative Example 21. The number average molecular weight of block copolymer b33 was 140,000 and the weight average molecular weight was 350,000.

[0459] The IEC of the aforementioned block copolymer b33 is 2.1 meq / g. Electrolyte membranes made using the aforementioned block copolymer b33 exhibit a co-continuous phase-separated structure (both hydrophilic domains containing ionic groups and hydrophobic domains without ionic groups form a continuous phase). Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 16.0 J / g. Therefore, the product of IEC and heat of crystallization is 33.6.

[0460] [Comparative Example 24]

[0461] <Synthesis of nonionic oligomer a35 represented by the following general formula (G14)>

[0462] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 16.59 g of potassium carbonate (artrich reagent, 120 mmol), 25.8 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, and 20.3 g of 4,4'-difluorobenzophenone (artrich reagent, 93 mmol). After nitrogen purging, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 160 °C, followed by heating to remove the toluene, and polymerization was carried out at 180 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of methanol to obtain the terminal hydroxyl body of the nonionic oligomer a35. The number average molecular weight of the terminal hydroxyl body of the nonionic oligomer a35 was 10,000.

[0463] 1.1 g of potassium carbonate (artrich reagent, 8 mmol) and 20.0 g (2 mmol) of the terminal hydroxyl group of nonionic oligomer a35 were added to a 500 mL three-necked flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging, 100 mL of NMP and 30 mL of cyclohexane were added. Dehydration was carried out at 100 °C, followed by heating to remove the cyclohexane. 3.0 g of bis(4-fluorophenyl sulfone) (artrich reagent, 12 mmol) was added, and the reaction was carried out at 105 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain nonionic oligomer a35 (terminal: fluorine group) represented by the following general formula (G14). The number average molecular weight of nonionic oligomer a35 is 11000. It should be noted that in the general formula (G14), m represents an integer greater than or equal to 1.

[0464]

[0465] <Synthesis of the ionic oligomer a38 represented by the above general formula (G5)>

[0466] A 2000 mL SUS polymerization apparatus equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator was charged with 27.6 g of potassium carbonate (Artrich reagent, 200 mmol), 12.9 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.3 g (Artrich reagent, 50 mmol), 40.1 g (95 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 17.9 g (Wako Purity, 82 mmol). After nitrogen purging, 300 mL of NMP and 100 mL of toluene were added. Dehydration was carried out at 1170 °C, followed by heating to remove the toluene. Polymerization was then carried out at 180 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain the ionic oligomer a38 (terminal: OM group) represented by the above general formula (G5). The number average molecular weight of this ionic oligomer a38 is 21,000.

[0467] <Synthesis of Block Copolymer B34>

[0468] Block copolymer b34 contains the aforementioned oligomer a38 as an ionic segment and the aforementioned oligomer a35 as a nonionic segment.

[0469] 0.56 g of potassium carbonate (Aldrich reagent, 4 mmol) and 21 g (1 mmol) of ionic oligomer a38 were added to a 500 mL three-necked flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark separator. After nitrogen purging, 100 mL of NMP and 30 mL of cyclohexane were added. Dehydration was carried out at 100 °C, followed by heating to remove the cyclohexane. 11 g (1 mmol) of nonionic oligomer a35 was then added, and the reaction was carried out at 105 °C for 24 hours. Purification was achieved by reprecipitation with a large amount of isopropanol to obtain block copolymer b34. The number average molecular weight of block copolymer b34 was 140,000, and the weight average molecular weight was 320,000.

[0470] The IEC of the aforementioned block copolymer b34 is 2.2 meq / g. A layered phase-separated structure was confirmed in the electrolyte membrane prepared using the aforementioned block copolymer b34. Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 12.5 J / g. Therefore, the product of IEC and heat of crystallization is 27.5.

[0471] [Comparative Example 25]

[0472] <Synthesis of nonionic oligomer a37 represented by the following general formula (G15)>

[0473] 13.82 g of potassium carbonate (artrich reagent, 100 mmol), 20.66 g (artrich reagent, 96 mmol) of K-DHBP obtained in Synthesis Example 1, and 20.95 g (artrich reagent, 96 mmol) of 4,4'-difluorobenzophenone were added to a 500 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark water separator. After nitrogen purging of the apparatus, 90 mL of NMP and 45 mL of toluene were added. Dehydration was carried out at 180 °C, followed by heating to remove the toluene, and polymerization was performed at 210 °C for 1 hour. Purification was achieved by reprecipitation with a large amount of water, and washing with hot methanol to obtain the nonionic oligomer a37 represented by the following general formula (G15). The number average molecular weight of this nonionic oligomer a37 is 3000. It should be noted that in general formula (G15), N3 represents an integer greater than or equal to 1.

[0474]

[0475] Synthesis of block copolymer b35

[0476] 8.29 g of potassium carbonate (Artrich reagent, 60 mmol), 8.94 g of 4,4'-biphenol (Artrich reagent, 48 mmol), and 16.89 g (40 mmol) of disodium 3,3'-disulfonated-4,4'-difluorobenzophenone obtained in Synthesis Example 2 were added to a 500 mL three-necked flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark separator. After nitrogen purging of the apparatus, 90 mL of NMP and 45 mL of toluene were added. Dehydration was carried out at 180 °C, followed by heating to remove the toluene. Polymerization was then carried out at 210 °C for 1 hour to obtain ionic oligomer a40. The number average molecular weight of this ionic oligomer a40 is 4000.

[0477] Next, 17.46 g (40 mmol) of nonionic oligomer a37 and 20 mL of toluene were added. After dehydration at 180 °C, the toluene was removed by heating. Polymerization was then carried out at 230 °C for 8 hours to obtain block copolymer b35. The number average molecular weight of block copolymer b35 is 110,000, and the weight average molecular weight is 271,000.

[0478] The IEC of the aforementioned block copolymer b35 is 2.1 meq / g. An island-like phase-separated structure was confirmed in the electrolyte membrane prepared using the aforementioned block copolymer b35. Furthermore, a crystallization peak was observed by DSC, with a heat of crystallization of 11.1 J / g. Therefore, the product of IEC and heat of crystallization is 23.3.

[0479] [Comparative Example 26]

[0480] <Block copolymer b36>

[0481] As block copolymer b36, the aforementioned block copolymer b8 was used. For the aforementioned block copolymer b36, no crystallization peak was observed by DSC. Therefore, the product of IEC and heat of crystallization could not be calculated.

[0482] [Measurement Results]

[0483] The measurement results of the electrolyte materials obtained in Examples 21-27 and Comparative Examples 21-26 are shown in Table 3.

[0484] [Table 3]

[0485]

[0486] In Examples 21-27, an electrolyte material (II) with an IEC of 1.8 meq / g or higher and 3.0 meq / g or lower, and a product of IEC and heat of crystallization (J / g) of 35.0 or higher and 47.0 or lower, was used. Therefore, the dry-wet dimensional change rate was small, and the proton conductivity under both low and high humidification conditions was increased. That is, mechanical durability and proton conductivity were achieved simultaneously at a high level.

[0487] On the other hand, in Comparative Examples 21–26, either the IEC or the product of IEC and heat of crystallization (J / g) deviated from the above range, indicating poor dry-wet dimensional change rate or proton conductivity. That is, mechanical durability and proton conductivity were not simultaneously achieved.

[0488] In this invention, from the viewpoint of simultaneously achieving high levels of mechanical durability and proton conductivity, it is preferable that the wet-dry dimensional change rate is 7.0% or less, and the low-humidification proton conductivity is 0.85 mS / cm or more, and the high-humidification proton conductivity is 9.00 mS / cm or more; more preferably, the wet-dry dimensional change rate is 6.5% or less, and the low-humidification proton conductivity is 0.90 mS / cm or more, and the high-humidification proton conductivity is 9.50 mS / cm or more; even more preferably, the wet-dry dimensional change rate is 6.0% or less, and the low-humidification proton conductivity is 1.00 mS / cm or more, and the high-humidification proton conductivity is 11.00 mS / cm or more; particularly preferably, the wet-dry dimensional change rate is 5.7% or less, and the low-humidification proton conductivity is 1.10 mS / cm or more, and the high-humidification proton conductivity is 13.00 mS / cm or more.

[0489] Explanation of reference numerals in the attached figures

[0490] 1 phase 1

[0491] 2 phases 2

Claims

1. A polymeric electrolyte material composed of block copolymers, wherein the block copolymers have segments containing ionic groups and segments not containing ionic groups, the polymeric electrolyte material having a phase-separated structure, and satisfying at least one of conditions 1 and 2 below, wherein the segments containing ionic groups are referred to as "ionic segments" and the segments not containing ionic groups are referred to as "non-ionic segments", wherein the number-average molecular weight of the ionic segments is set as Mn1 and the number-average molecular weight of the non-ionic segments is set as Mn2, wherein Mn2 is 15000 or more, and Mn1 and Mn2 satisfy the following Equation 1: 1.7 ≤ Mn1 / Mn2 ≤ 7.0 (Equation 1) <Condition 1> The saturated crystallinity of the polymeric electrolyte material, as determined by wide-angle X-ray diffraction, is 5% or more and 30% or less; <Condition 2> The ion exchange capacity (IEC) of the polymeric electrolyte material is 1.8 meq / g or more and 3.0 meq / g or less, and the product of the IEC of the polymeric electrolyte material in meq / g and the heat of crystallization of the polymeric electrolyte material in J / g as determined by differential scanning calorimetry is 35.0 or more and 47.0 or less.

2. The polymeric electrolyte material according to claim 1, wherein the polymeric electrolyte material has a co-continuous phase separation structure or a layered phase separation structure.

3. The polymeric electrolyte material according to claim 1 or 2, wherein the average period size of the phase separation structure is 15 to 100 nm.

4. The polymeric electrolyte material according to claim 1 or 2, wherein the block copolymer is an aromatic polyether copolymer.

5. The polymeric electrolyte material according to claim 1 or 2, wherein the block copolymer is an aromatic polyether ketone copolymer.

6. The polymeric electrolyte material according to claim 1 or 2, wherein the block copolymer has a connecting portion that bonds the ionic segments and the nonionic segments.

7. The polymeric electrolyte material according to claim 1 or 2, wherein the nonionic segment contains a structure represented by the following general formula (S3), In general formula (S3), Ar 5 ~Ar 8 Each can be independently represented as either a substituted arylene or an unsubstituted arylene, where Ar 5 ~Ar 8 Neither of them has ionic groups, Y 3 and Y 4 Each of the following groups represents a ketone group and a protecting group that can be derived into a ketone group, and * indicates a bond with the general formula (S3) or other structural units.

8. The polymeric electrolyte material according to claim 7, wherein the structure represented by the general formula (S3) is the structure represented by the following general formula (S4). In general formula (S4), Y 3 and Y 4 Each group independently represents a ketone group or a protecting group that can be derived into a ketone group, and * indicates a bond with the general formula (S4) or other structural units.

9. A polymeric electrolyte molded body comprising the polymeric electrolyte material according to any one of claims 1 to 8.

10. An electrolyte membrane with a catalyst layer, which is constructed using the polymer electrolyte molded body as described in claim 9.

11. A membrane electrode assembly comprising a polymer electrolyte molded body as described in claim 9.

12. A solid polymer fuel cell, which is constructed using the polymer electrolyte molded body as described in claim 9.

13. A water electrolysis type hydrogen generator, which is constructed using the polymer electrolyte molded body as described in claim 9.

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