Polymer electrolyte material, polymer electrolyte molded body using same, electrolytic membrane having catalyst layer attached thereto, membrane-electrode assembly, solid polymer fuel cell, and water-electrolysis-type hydrogen generator

Abstract

Provided is a polymer electrolyte material which comprises a block copolymer having both of a segment having an ionic group (which is also referred to as an "ionic segment", hereinafter) and a segment containing no ionic group (which is also referred to as a "non-ionic segment", hereinafter), in which the polymer electrolyte material has a phase-separated structure and satisfies at least one of requirement 1 and requirement 2. <Requirement 1> The saturated crystallization degree of the polymer electrolytic material which is measured by wide-angle X-ray diffraction is 5% to 30% inclusive. <Requirement 2> The ion exchange capacity (IEC) of the polymer electrolyte material is 1.8 meq / g to 3.0 meq / g inclusive, and the product of the IEC (meq / g) of the polymer electrolyte material and the quantity of heat of crystallization (J / g) of the polymer electrolyte material which is measured by a differential scanning calorimetric method is 35.0 to 47.0 inclusive.　A polymer electrolyte material is provided, which has satisfactory mechanical durability and excellent proton conductivity.

Description

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

[0001] The present invention relates to a polymer electrolyte material, a polymer electrolyte molded body using the same, an electrolyte membrane with a catalyst layer, a membrane electrode assembly, a solid polymer fuel cell, and a water electrolysis type hydrogen generator.

[0002] Fuel cells are a type of power generation device that generates electrical energy by electrochemically oxidizing fuels such as hydrogen and methanol, and have recently attracted attention as a clean energy source. Polymer electrolyte fuel cells, in particular, have a low standard operating temperature of around 100°C and a high energy density, making them promising for a wide range of applications, including as a power generation device for relatively small-scale distributed power generation facilities and for mobile devices such as automobiles and ships. Polymer electrolyte fuel cells are also attracting attention as power sources for small mobile and portable devices, and are expected to replace secondary batteries such as nickel-metal hydride batteries and lithium-ion batteries in mobile phones and personal computers.

[0003] A fuel cell is typically constructed with a cell unit, in which a membrane electrode assembly (MEA) is sandwiched between separators. The MEA has catalyst layers arranged on both sides of an electrolyte membrane, and gas diffusion layers arranged on both sides of the catalyst layers. In the MEA, a pair of electrode layers is formed by the catalyst layers and gas diffusion layers arranged on both sides of the electrolyte membrane, one of which is an anode electrode and the other is a cathode electrode. Electricity is generated by an electrochemical reaction when a fuel gas containing hydrogen comes into contact with the anode electrode and air comes into contact with the cathode electrode. The electrolyte membrane is primarily composed of a polymer electrolyte material. The polymer electrolyte material is also used as a binder for the catalyst layer.

[0004] Conventionally, the fluorine-based polymer electrolyte "Nafion" (registered trademark) (manufactured by Chemours Corporation) has been widely used as a polymer electrolyte material. Meanwhile, development of hydrocarbon-based electrolyte materials that are inexpensive and have excellent membrane properties and can replace "Nafion" has been active in recent years. Hydrocarbon-based electrolyte materials have excellent low gas permeability and heat resistance, and electrolyte materials using aromatic polyether ketones and aromatic polyether sulfones have been particularly actively studied. However, while conventional hydrocarbon-based electrolyte materials exhibit proton conductivity equivalent to or superior to that of fluorine-based electrolyte materials under highly humidified conditions, their proton conductivity is insufficient.

[0005] To address the above-mentioned problems, electrolyte membranes having a phase-separated structure have been proposed as hydrocarbon-based polymer electrolyte membranes with improved proton conductivity and mechanical durability (see, for example, Patent Documents 1 and 2).

[0006] International Publication No. WO 2008 / 018487 International Publication No. WO 2013 / 031675

[0007] The polymer electrolyte membranes disclosed in the above patent documents are expected to have improved proton conductivity and mechanical durability.

[0008] However, proton conductivity and mechanical durability generally have a trade-off relationship, that is, increasing proton conductivity decreases mechanical durability, and conversely, increasing mechanical durability decreases proton conductivity. Therefore, even when the electrolyte membranes described in Patent Documents 1 and 2 are used, it is difficult to achieve both of these properties at a relatively high level.

[0009] In view of the background of the prior art, the present invention aims to provide a polymer electrolyte material that achieves both proton conductivity and mechanical durability at a relatively high level.

[0010] In order to solve the above problems, the polymer electrolyte material of the present invention has the following configuration: That is, the polymer electrolyte material is a polymer electrolyte material composed of a block copolymer having segments each containing an ionic group and a segment each not containing an ionic group, the polymer electrolyte material having a phase-separated structure and satisfying at least one of the following conditions 1 and 2: <Condition 1> The saturated crystallinity of the polymer electrolyte material measured 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 measured by differential scanning calorimetry is 35.0 or more and 47.0 or less.

[0011] In order to solve the above problems, the polymer electrolyte molded product of the present invention has the following configuration: Namely, the polymer electrolyte molded product includes the above polymer electrolyte material.

[0012] In order to solve the above problems, the catalyst-coated electrolyte membrane of the present invention has the following configuration: That is, the catalyst-coated electrolyte membrane is constructed using the above polymer electrolyte molded article.

[0013] In order to solve the above problems, the membrane electrode assembly of the present invention has the following configuration: That is, the membrane electrode assembly is constructed using the above polymer electrolyte molded article.

[0014] In order to solve the above problems, the solid polymer fuel cell of the present invention has the following configuration: That is, the solid polymer fuel cell is constructed using the above polymer electrolyte molded article.

[0015] The polymer electrolyte material of the present invention preferably has a bicontinuous or lamellar phase-separated structure.

[0016] In the polymer electrolyte material of the present invention, the average periodic size of the phase-separated structure is preferably 15 to 100 nm.

[0017] In the polymer electrolyte material of the present invention, the block copolymer is preferably an aromatic polyether copolymer.

[0018] In the polymer electrolyte material of the present invention, the block copolymer is preferably an aromatic polyether ketone copolymer.

[0019] In the polymer electrolyte material of the present invention, the block copolymer preferably has a linker moiety that bonds the ionic segment and the nonionic segment.

[0020] In the polymer electrolyte material of the present invention, the nonionic segment preferably contains a structure represented by the following general formula (S3):

[0021]

[0022] (In general formula (S3), Ar ５ ~Ar ８ each independently represents a substituted or unsubstituted arylene group. ５ ~Ar ８ None of the groups has an ionic group. ３ and Y ４ each independently represents a ketone group or a protecting group that can be derived to a ketone group. * represents a bond to general formula (S3) or another structural unit.) In the polymer electrolyte material of the present invention, the structure represented by general formula (S3) is preferably a structure represented by the following general formula (S4).

[0023]

[0024] (In general formula (S4), Y ３ and Y ４ each independently represents a ketone group or a protecting group that can be derived to a ketone group. * represents a bond to general formula (S4) or another structural unit.

[0025] In the polymer electrolyte material of the present invention, the number average molecular weight of the nonionic segment is preferably 15,000 or more.

[0026] According to the present invention, it is possible to provide a polymer electrolyte material that achieves both proton conductivity and mechanical durability at a relatively high level.

[0027] FIG. 1 is a schematic diagram of a phase-separated structure in a polymer electrolyte material.

[0028] Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be implemented with various modifications depending on the purpose and application.

[0029] The polymer electrolyte material of the present invention is composed of a block copolymer having a segment containing an ionic group (hereinafter referred to as an "ionic segment") and a segment not containing an ionic group (hereinafter referred to as a "nonionic segment"). A polymer electrolyte material composed of such a block polymer has the advantage of easily forming a phase-separated structure. Hereinafter, the polymer electrolyte material may be simply referred to as an "electrolyte material."

[0030] The electrolyte material of the present invention has a phase-separated structure and satisfies at least one of the following conditions 1 and 2. Such an electrolyte material exhibits performance in which both mechanical durability and proton conductivity are achieved at a relatively high level. <Condition 1> The saturated crystallinity of the polymer electrolyte material measured 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 measured by differential scanning calorimetry is 35.0 or more and 47.0 or less.

[0031] Hereinafter, the saturated crystallinity of a polymer electrolyte material measured by wide-angle X-ray diffraction may be abbreviated as "saturated crystallinity," the ion exchange capacity as "IEC," and the heat of crystallization measured by differential scanning calorimetry as "heat of crystallization."

[0032] In the present invention, achieving both mechanical durability and proton conductivity at a relatively high level specifically means that the mechanical durability is relatively good and the proton conductivity is excellent, or that the proton conductivity is relatively good and the mechanical durability is excellent.

[0033] In the present invention, good mechanical durability means that an electrolyte membrane made of an electrolyte material has a small wet-dry dimensional change rate. Here, the wet-dry dimensional change rate of an electrolyte membrane can be determined by the following measurement. An electrolyte membrane test piece is subjected to a constant stress while being alternately exposed to a dry atmosphere (30% RH) and a humid atmosphere (90% RH), and a wet-dry cycle is repeatedly performed. The dimensional change rates (%) at 30% RH and 90% RH are measured at the 10th cycle, and the difference between the dimensional change rates (%) is defined as the wet-dry dimensional change rate (%).

[0034] In the present invention, confirmation of the phase separation structure of the electrolyte material, measurement of the saturated crystallinity and heat of crystallization of the electrolyte material, and evaluation of the mechanical durability (dry / wet dimensional change rate) and proton conductivity of the electrolyte material were each performed using a membrane (hereinafter referred to as "electrolyte membrane") obtained by applying a solution in which the electrolyte material was dissolved or dispersed in an appropriate solvent onto a support substrate and drying it. Hereinafter, the electrolyte material may be replaced with the electrolyte membrane in the description.

[0035] [Phase-separated structure] The electrolyte material of the present invention has a phase-separated structure. Here, the phrase "the electrolyte material has a phase-separated structure" means that the phase-separated structure can be confirmed when the electrolyte membrane is observed with a transmission electron microscope (TEM).

[0036] Examples of the phase-separated structure of an electrolyte membrane are shown in Figure 1. Phase-separated structures are broadly classified into four types: bicontinuous (M1), lamellar (M2), cylindrical (M3), and sea-island (M4). The electrolyte material of the present invention has any one of the phase-separated structures (M1) to (M4).

[0037] In (M1) to (M4) in FIG. 1, the continuous phase (phase 1) in the white portion is formed by one segment selected from the ionic segment and the nonionic segment, and the continuous or dispersed phase (phase 2) in the gray portion is formed by the other segment.

[0038] The above phase separation structure is described, for example, in Annual Review of Physical Chemistry, 41, 1990, p. 525.

[0039] By controlling the higher-order structure and shape of the ionic and nonionic segments, it is possible to achieve excellent proton conductivity even under low humidity and low temperature conditions. In other words, the phase-separated structure of the electrolyte membrane (M1) to (M4) enables the formation of continuous proton-conducting channels, thereby improving proton conductivity.

[0040] In a phase-separated structure consisting of bicontinuous (M1) and lamellar (M2), both the ionic and nonionic segments form a continuous phase. An electrolyte membrane having such a phase-separated structure has excellent proton conductivity due to the formation of continuous proton-conducting channels, and also has excellent mechanical durability due to the crystallinity of the domains consisting of the nonionic segments. That is, the electrolyte material of the present invention preferably has a bicontinuous (M1) or lamellar (M2) phase-separated structure, and more preferably has a bicontinuous (M1) phase-separated structure.

[0041] The domains mentioned above refer to clusters formed by the aggregation of similar segments in one or more polymer chains.

[0042] The following method can be used to confirm whether an electrolyte membrane has a bicontinuous (M1) or lamellar (M2) phase-separated structure. Specifically, a membrane is defined as having this structure when the desired image is observed using the following method. This method involves comparing three digital slice views cut from three directions (length, width, and height) with a three-dimensional image obtained by TEM tomography observation. For example, in an electrolyte membrane containing a block copolymer having ionic and nonionic segments, if the phase-separated structure is bicontinuous (M1) or lamellar (M2), both the hydrophilic domains containing the ionic segments and the hydrophobic domains containing the nonionic segments form continuous phases in all three views.

[0043] In the case of a bicontinuous phase (M1), each continuous phase exhibits an intricate pattern, while in the case of a lamellar phase (M2), each continuous phase exhibits a layered pattern. Here, the continuous phase refers to a phase in which, macroscopically, each domain is connected without being isolated, although some disconnected portions are acceptable.

[0044] On the other hand, in the case of a cylindrical structure (M3) or an islands-in-a-sea structure (M4), any of the domains does not form a continuous phase on at least one surface, and therefore, these structures can be distinguished from the co-continuous structure (M1) and lamellar structure (M2). In addition, the structures can be distinguished from the patterns shown in each of the three-view drawings.

[0045] In observing the phase-separated structure, in order to clarify the aggregation state and contrast of the ionic and nonionic segments, for example, the electrolyte membrane can be immersed in a 2 wt % lead acetate aqueous solution for 2 days to ion-exchange the ionic groups with lead, and then the membrane can be observed with a transmission electron microscope (TEM) and TEM tomography.

[0046] The size of the phase-separated structure can be expressed as the periodic size of the hydrophilic domains containing ionic segments and the hydrophobic domains containing nonionic segments. The periodic size of the phase-separated structure can be estimated from the autocorrelation function given by image processing of the phase-separated structure obtained by transmission electron microscope (TEM) observation.

[0047] From the viewpoints of proton conductivity and mechanical durability, the average periodic size of the phase-separated structure is preferably in the range of 15 to 100 nm, more preferably in the range of 35 to 80 nm, even more preferably in the range of 40 to 67 nm, and particularly preferably in the range of 48 to 67 nm. Furthermore, if the average periodic size of the phase-separated structure is greater than 100 nm, it becomes difficult to form a bicontinuous-like phase-separated structure, so the average periodic size is preferably in the above range from the viewpoint of obtaining a bicontinuous-like phase-separated structure.

[0048] [Electrolyte Material According to First Embodiment] The electrolyte material according to the first embodiment of the present invention (hereinafter referred to as "electrolyte material (I)") satisfies condition 1. That is, the electrolyte material (I) has a saturated crystallinity of 5% or more and 30% or less.

[0049] (Saturated Crystallinity) The saturated crystallinity refers to the crystallinity at which crystallization does not proceed any further, i.e., the maximum crystallinity. Specifically, an electrolyte membrane made of the above-mentioned electrolyte material is hot-pressed at 4.5 MPa at a temperature equal to or higher than the glass transition temperature (Tg) of the electrolyte material, and the crystallinity is measured by wide-angle X-ray diffraction every 5 minutes. The crystallinity at which the crystallinity no longer changes is considered to be the saturated crystallinity. The heating temperature (T (°C)) during hot-pressing is in the range of Tg≦T≦Tg+40°C. Specifically, Tg+5°C is appropriate.

[0050] 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) exceeds 30%, the proton conductivity and processability decrease. From the viewpoint of proton conductivity and processability, the saturated crystallinity is preferably 25% or less, more preferably 23% or less, even more preferably 20% or less, and particularly preferably 17% or less.

[0051] When the electrolyte material is applied to electrochemical applications such as solid polymer fuel cells and water electrolysis hydrogen generators, it is generally processed into a molded electrolyte membrane as described below for use. The crystallinity of the molded electrolyte membrane using the electrolyte material (I) can reach the saturated crystallinity described above, but it is not necessarily required to reach the saturated crystallinity.

[0052] A molded electrolyte membrane using the electrolyte material (I), i.e., a molded electrolyte membrane using an electrolyte material composed of a block copolymer having both ionic and nonionic segments, has good mechanical durability and excellent proton conductivity even if its crystallinity does not reach the saturated crystallinity of the electrolyte material. For example, it has been confirmed that the molded electrolyte membrane has good mechanical durability and excellent proton conductivity even when crystallization of the membrane has hardly progressed.

[0053] The crystallinity of a cast electrolyte membrane using the electrolyte material (I) can be increased by heating it at a temperature equal to or higher than the glass transition temperature of the electrolyte material (I). This can further improve the proton conductivity and mechanical durability of the cast electrolyte membrane. In this case, the crystallinity of the cast electrolyte membrane may be increased to the same level as the saturated crystallinity of the electrolyte material (I), or may be increased to about 1 to 99% of the saturated crystallinity of the electrolyte material (I). A method for adjusting the crystallinity of the cast electrolyte membrane will be described later.

[0054] The IEC of the electrolyte material (I) is not particularly limited, but is preferably 1.5 meq / g or more, more preferably 1.8 meq / g or more, even more preferably 1.9 meq / g or more, and particularly preferably 2.0 meq / g or more. The IEC of the electrolyte material (I) is preferably 3.5 meq / g or less, more preferably 3.0 meq / g or less, even more preferably 2.9 meq / g or less, and particularly preferably 2.8 meq / g or less.

[0055] IEC is the molar amount of ion exchange groups introduced per unit dry mass of an electrolyte material (block copolymer). IEC can be measured by elemental analysis, neutralization titration, or the like. When the ion exchange groups are sulfonic acid groups, elemental analysis can be used to calculate the IEC from the S / C ratio. However, when a sulfur source other than sulfonic acid groups is contained, measurement is difficult. Therefore, in the present invention, IEC is defined as the value determined by the neutralization titration method described below.

[0056] [Electrolyte Material According to Second Embodiment] An electrolyte material according to a 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 the IEC and the heat of crystallization is 35.0 or more and 47.0 or less.

[0057] (IEC) The electrolyte material (II) has an IEC of 1.8 meq / g or more and 3.0 meq / g or less. An electrolyte material (II) having an IEC in the above range has excellent proton conductivity. From the viewpoint of enhancing proton conductivity, the IEC of the electrolyte material (II) is preferably 1.9 meq / g or more, more preferably 2.0 meq / g or more, even more preferably 2.1 meq / g or more, and particularly preferably 2.2 meq / g or more. Furthermore, from the viewpoint of ensuring high mechanical durability, the IEC is preferably 2.9 meq / g or less, more preferably 2.8 meq / g or less, and particularly preferably 2.6 meq / g or less.

[0058] (Crystallization Heat) The electrolyte material (II) has crystallinity. Here, "crystallinity" means that the electrolyte material has the property of crystallizing at elevated temperatures. The degree of crystallinity can be expressed as the crystallization heat measured by differential scanning calorimetry (DSC). In addition, a crystallization heat of 0.1 J / g or more is an indicator of whether an electrolyte material has crystallinity.

[0059] As the differential scanning calorimetry (DSC) in the present invention, the following analytical method can be used.

[0060] 10 mg of a sample (electrolyte membrane) was pre-dried in a DSC instrument at 110°C for 3 hours, and then, without removing the sample from the DSC instrument, the temperature was raised to 200°C under the following conditions to perform temperature-modulated differential scanning calorimetry (TMS) during the heating stage. The sample used was the electrolyte membrane obtained by applying a solution of the electrolyte material dissolved or dispersed in an appropriate solvent onto a support substrate and drying it. Measurement temperature range: 30°C to 200°C Temperature control: AC temperature control Heating rate: 2°C / min Amplitude: ±3°C Applied frequency: 0.02 Hz Sample pan: Aluminum crimp pan Measurement and pre-drying atmosphere: Nitrogen 100 mL / min

[0061] The differential scanning calorimetry (DSC) has the advantage over conventional analytical methods that the sample is not exposed to the atmosphere (air) from pre-drying to measurement, and therefore the sample is less susceptible to the influence of moisture in the atmosphere, thereby improving measurement accuracy.

[0062] (Product of IEC and Heat of Crystallization) The electrolyte material (II) has a product of its IEC (meq / g) and heat of crystallization (J / g) of 35.0 or more and 47.0 or less.

[0063] As mentioned above, proton conductivity and mechanical durability are generally in a trade-off relationship. However, when the IEC is in the range of 1.8 meqJ / g or more and 3.0 meq / g or less, by setting the product of the IEC and the heat of crystallization to 35.0 or more and 47.0 or less, it is possible to achieve both proton conductivity and mechanical durability at a relatively high level.

[0064] As mentioned above, in electrolyte membranes, proton conductivity and mechanical durability generally have a trade-off relationship. Furthermore, proton conductivity and IEC, and mechanical durability and heat of crystallization are roughly correlated with each other. That is, the IEC and heat of crystallization are characteristics with vectors in opposite directions. The inventors have found that the physical quantity obtained by multiplying the IEC and heat of crystallization is effective as an index for achieving both proton conductivity and mechanical durability, and that the physical quantity obtained by multiplying the IEC and heat of crystallization is particularly effective in the IEC range of 1.8 meq / g to 3.0 meq / g, and that when the physical quantity is in the range of 35.0 to 47.0, proton conductivity and mechanical durability can be achieved at a relatively high level.

[0065] From the above viewpoint, the product of the IEC and the heat of crystallization is preferably 36.0 or more and 47.0 or less, and more preferably 37.0 or more and 44.0 or less.

[0066] The heat of crystallization of the electrolyte material (II) is designed so that the product of IEC and heat of crystallization is within the above 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. 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 exceeds the above range, the electrolyte membrane tends to become brittle, while if the heat of crystallization is smaller than the above range, the mechanical durability tends to decrease.

[0067] The IEC of the electrolyte material (II) can be adjusted, for example, by controlling the density of sulfonic acid groups in the block copolymer, the content of ionic segments in the block copolymer, etc. The heat of crystallization of the electrolyte material (II) can be adjusted, for example, by controlling the structure of the nonionic segment, the molecular weight of the nonionic segment, the content of nonionic segments in the block copolymer, etc. Details will be described later.

[0068] Hereinafter, matters common to the electrolyte material of the present invention, including the electrolyte material according to the first embodiment and the electrolyte material according to the second embodiment, will be described. In the following description, the term "electrolyte material of the present invention" naturally includes the electrolyte material (I) and the electrolyte material (II).

[0069] [Block Copolymer] The electrolyte material of the present invention comprises a block copolymer having an ionic segment and a nonionic segment. In the present invention, a segment refers to a partial structure in the block copolymer of a macromonomer used in synthesizing the block copolymer. Although the nonionic segment is described as not containing an ionic group, it may contain a small amount of ionic groups as long as it does not adversely affect the effects of the present invention, particularly crystallinity.

[0070] The block copolymer constituting the polymer electrolyte material of the present invention is a polymer chain formed by linking two or more types of mutually incompatible segment chains, i.e., hydrophilic ionic segments and hydrophobic nonionic segments. In block copolymers, repulsion between chemically different segment chains results in phase separation into nano- or microdomains composed of each segment chain. Furthermore, covalent bonding between the segment chains creates long-range interactions, which result in each domain being arranged in a specific order. The higher-order structure formed by the aggregation of domains composed of each segment chain is called a nano- or microphase-separated structure. Here, a domain refers to a mass formed by the aggregation of similar segments in one or more polymer chains. For ionic conduction in electrolyte membranes, the spatial arrangement of ion-conducting segments in the membrane, i.e., the nano- or microphase-separated structure, is important.

[0071] [Ionic Segment] The ionic segment in the block copolymer constituting the polymer electrolyte material of the present invention is preferably a hydrocarbon-based polymer from the viewpoints of crystallinity and mechanical durability. Here, "hydrocarbon-based" means a polymer other than a perfluoro-based polymer, and "hydrocarbon-based polymer" means a polymer other than a perfluoro-based polymer.

[0072] Furthermore, from the viewpoint of crystallinity and mechanical durability, the ionic segment is preferably a hydrocarbon polymer having an aromatic ring in the main chain (hereinafter referred to as an "aromatic hydrocarbon polymer").

[0073] The aromatic ring contained in the aromatic hydrocarbon polymer may contain not only a hydrocarbon aromatic ring but also a heterocycle. Furthermore, the polymer may also contain some aliphatic units together with the aromatic ring units. Specific examples of aromatic hydrocarbon polymers include polymers having, in the main chain together with an aromatic ring, a structure selected from polysulfone, polyethersulfone, polyphenylene oxide, polyarylene ether polymer, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, polyarylene polymer, polyarylene ketone, polyether ketone, polyarylene phosphine oxide, polyether phosphine oxide, polybenzoxazole, polybenzothiazole, polybenzimidazole, polyamide, polyimide, polyetherimide, and polyimide sulfone. Among these, aromatic polyether polymers are preferred from the viewpoints of cost and polymerizability.

[0074] An aromatic polyether polymer refers to a polymer primarily composed of aromatic rings, in which the repeating units contain at least an ether bond as a linking mechanism between the aromatic ring units. Examples of the structure of the aromatic polyether polymer include, but are not limited to, aromatic polyether, aromatic polyether ketone, aromatic polyether imide, and aromatic polyether sulfone. From the viewpoints of chemical stability and cost, aromatic polyether ketone polymers and aromatic polyether sulfone polymers are preferred, and from the viewpoints of mechanical durability and physical durability, aromatic polyether ketone polymers are most preferred.

[0075] The aromatic polyetherketone polymer refers to a polymer mainly composed of aromatic rings, in which the repeating units contain at least an ether bond and a ketone bond as a linking mode of the aromatic ring units. The aromatic polyetherketone polymer includes aromatic polyetherketone, aromatic polyetheretherketone, aromatic polyetherketoneketone, aromatic polyetheretherketoneketone, aromatic polyetherketoneetherketoneketone, aromatic polyetherketoneetherketoneketone, etc.

[0076] The aromatic polyethersulfone polymer refers to a polymer mainly composed of aromatic rings, in which the repeating units contain at least an ether bond and a sulfone bond as the linking mode of the aromatic ring units.

[0077] The ionic segment used in the present invention can be synthesized by an aromatic nucleophilic substitution reaction, a coupling reaction, or the like.

[0078] As described above, the ionic segment is preferably an aromatic polyether polymer, and the aromatic polyether polymer preferably contains a structure represented by the following general formula (S1).

[0079]

[0080] In general formula (S1), Ar １ ~Ar ４ each independently represents a substituted or unsubstituted arylene group; Ar １ ~Ar ４ At least one of Y has an ionic group. １ and Y ２ each independently represents a ketone group or a protecting group that can be derived to a ketone group. * represents a bond to general formula (S1) or another structural unit.

[0081] Here, Ar １ ~Ar ４ Examples of the arylene group represented by the formula (I) include, but are not limited to, hydrocarbon arylene groups such as phenylene, naphthylene, biphenylene, and fluorenediyl groups, and heteroarylene groups such as pyridinediyl, quinoxalinediyl, and thiophenediyl. The ionic group is preferably an atomic group having a negative charge, and preferably has proton exchange ability. Examples of such functional groups include, but are not limited to, sulfonic acid groups, sulfonimide groups, sulfate groups, phosphonic acid groups, phosphate groups, and carboxylic acid groups.

[0082] The ionic group may be in the form of a salt. Examples of the cation that forms such a salt include any metal cation, NR ４ ＋(R is any organic group) etc. There is no particular limitation on the metal cation, but Na, K and Li are preferred because they are inexpensive and can be easily proton-substituted.

[0083] Two or more types of these ionic groups can be contained in the ionic segment, and the combination is appropriately determined depending on the structure of the block copolymer, etc. Among them, it is more preferable to contain at least a sulfonic acid group, a sulfonimide group, or a sulfate group from the viewpoint of high proton conductivity, and it is particularly preferable to contain a sulfonic acid group from the viewpoint of raw material costs.

[0084] In addition, in the general formula (S1), Y １ and Y ２ From the viewpoint of forming a phase-separated structure, the ionic segment is preferably a ketone group or a protecting group that can be derived to a ketone group. That is, the ionic segment is preferably an aromatic polyether ketone polymer. Protecting groups that can be derived to a ketone group will be described later.

[0085] The structure represented by the above general formula (S1) is preferably a structure represented by the following general formula (P1) from the viewpoint of raw material availability, and among these, a structure represented by the following general formula (S2) is more preferable from the viewpoint of raw material availability and polymerizability.

[0086]

[0087] In general formula (P1) and general formula (S2), Y １ and Y ２ each independently represents a ketone group or a protecting group that can be derivatized to a ketone group. １ ~M ４ Each of n independently represents a hydrogen atom, a metal cation, or an ammonium cation. １ ~n ４ are each independently 0 or 1, and n １ ~n ４ At least one of the formulas is 1. * represents a bond to the general formula (P1), (S2) or other structural units.

[0088] Furthermore, in terms of raw material availability and polymerizability, １ = 1, n ２ = 1, n ３= 0, n ４ = 0 or n １ = 0, n ２ = 0, n ３ = 1, n ４ It is most preferred that .gamma..times ...

[0089] Examples of ionic monomers used to synthesize the constituent units of the ionic segment include aromatic active dihalide compounds. Using a compound in which an ionic acid group has been introduced into an aromatic active dihalide compound as the aromatic active dihalide compound used in the ionic segment is preferred in terms of chemical stability, production costs, and the ability to precisely control the amount of ionic group. Specific examples of suitable monomers having a sulfonic acid group as the ionic group include, but are not limited to, 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'-dichlorodiphenylphenylphosphine oxide, and 3,3'-disulfonate-4,4'-difluorodiphenylphenylphosphine oxide.

[0090] From the viewpoint of proton conductivity and hydrolysis resistance, the sulfonic acid group is most preferable as the ionic group, but the monomer having the above ionic group may also have other ionic groups.

[0091] Among the above-mentioned monomers having a sulfonic acid group, 3,3'-disulfonate-4,4'-dichlorodiphenyl ketone and 3,3'-disulfonate-4,4'-difluorodiphenyl ketone are more preferred from the viewpoint of chemical stability and physical durability, and 3,3'-disulfonate-4,4'-difluorodiphenyl ketone is most preferred from the viewpoint of polymerization activity.

[0092] Ionic segments synthesized using 3,3'-disulfonate-4,4'-dichlorodiphenyl ketone or 3,3'-disulfonate-4,4'-difluorodiphenyl ketone as a monomer having an ionic group include a structural unit represented by the following general formula (p1), and are preferably used. In addition to the high crystallinity characteristic of the ketone group, such aromatic polyether polymers are components that have superior hot water resistance compared to sulfone groups, making them effective components for materials that exhibit excellent dimensional stability, mechanical strength, and physical durability under high-temperature, high-humidity conditions, and are therefore even more preferably used. It is preferable that these sulfonic acid groups form salts with monovalent cation species during polymerization. The monovalent cation species may be, but is not limited to, sodium, potassium, other metal species, various amines, and the like. These aromatic active dihalide compounds can be used alone, or multiple aromatic active dihalide compounds can be used in combination.

[0093]

[0094] (In general formula (p1), M １ and M ２ represents hydrogen, a metal cation, or an ammonium cation, and a1 and a2 represent integers of 1 to 4. The structural unit represented by general formula (p1) may be optionally substituted.) It is also possible to control the ionic group density by copolymerizing aromatic active dihalide compounds having and not having ionic groups. However, from the viewpoint of ensuring the continuity of the proton conduction path, it is more preferable not to copolymerize aromatic active dihalide compounds having no ionic groups as the ionic segment.

[0095] More preferred specific examples of aromatic active dihalide compounds having no ionic group 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, 2,6-difluorobenzonitrile, etc. Among these, 4,4'-dichlorodiphenyl ketone and 4,4'-difluorodiphenyl ketone are more preferred in terms of imparting 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 dihalide compounds can be used alone, or multiple aromatic active dihalide compounds can be used in combination.

[0096] Polymer electrolyte materials synthesized using 4,4'-dichlorodiphenyl ketone or 4,4'-difluorodiphenyl ketone as the aromatic active dihalide compound further contain a constituent moiety represented by the following general formula (p2), and are preferably used. This constituent unit is a component that imparts intermolecular cohesion and crystallinity, and is therefore preferably used because it results in a material that is excellent in dimensional stability, mechanical strength, and physical durability under high-temperature and high-humidity conditions.

[0097]

[0098] (The structural unit represented by general formula (p2) may be optionally substituted, but does not contain an ionic group.) Furthermore, examples of nonionic monomers used to synthesize the ionic segment include aromatic diphenol compounds, and aromatic diphenol compounds having a protecting group, which will be described later, are particularly preferred.

[0099] The monomers used to synthesize the building blocks of the ionic segment have been described above.

[0100] The ionic segment or the structural units constituting the ionic segment may include structures represented by the following general formulas (T1) and (T2) in addition to the structure represented by general formula (S1).

[0101]

[0102] In formulae (T1) and (T2), B represents a divalent organic group containing an aromatic ring. ５ and M ６ each independently represents a hydrogen atom, a metal cation, or an ammonium cation.

[0103] 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).

[0104] It is particularly preferred that the ionic segment has a structure represented by general formula (P1) and structures represented by general formulas (T1) and (T2). In such an ionic segment, when the amounts of the structural units represented by general formulas (P1), (T1), and (T2) are p1, t1, and t2, respectively, the total molar amount of t1 and t2 is 100 parts by mole, and p1 is preferably 75 parts by mole or more, more preferably 90 parts by mole or more, and even more preferably 100 parts by mole or more.

[0105] Examples of the divalent organic group B containing an aromatic ring in general formulas (T1) and (T2) include residues of various dihydric phenol compounds that can be used in the polymerization of aromatic polyether polymers by aromatic nucleophilic substitution reactions, and residues of such dihydric phenol compounds to which a sulfonic acid group has been introduced. Specific examples of suitable divalent organic group B containing an aromatic ring include, but are not limited to, groups represented by the following general formulas (X'-1) to (X'-6):

[0106]

[0107] These may have an ionic group or an aromatic group. These may also be used in combination as needed. Among these, from the viewpoints of crystallinity, dimensional stability, toughness, and chemical stability, the groups represented by general formulas (X'-1) to (X'-4) are more preferred, and the groups represented by general formulas (X'-2) and (X'-3) are most preferred.

[0108] [Nonionic Segment] From the viewpoints of crystallinity and mechanical durability, the nonionic segment constituting the block copolymer of the present invention is preferably a hydrocarbon polymer, more preferably an aromatic hydrocarbon polymer. Here, the definition of the hydrocarbon polymer and specific examples of the aromatic hydrocarbon polymer are as described above.

[0109] Among aromatic hydrocarbon polymers, aromatic polyether polymers are preferred from the viewpoints of cost and polymerizability, and aromatic polyether ketone polymers and aromatic polyether sulfone polymers are preferred from the viewpoints of mechanical durability and physical durability, with aromatic polyether ketone polymers being particularly preferred.

[0110] As described above, the nonionic segment is preferably an aromatic polyether polymer, and the aromatic polyether polymer preferably contains a structure represented by the following general formula (S3).

[0111]

[0112] In general formula (S3), Ar ５ ~Ar ８ each independently represents a substituted or unsubstituted arylene group. ５ ~Ar ８ None of the groups has an ionic group. ３ and Y ４ each independently represents a ketone group or a protecting group that can be derived to a ketone group. * represents a bond to general formula (S3) or another structural unit.

[0113] Here, Ar ５ ~Ar ８ Examples of the arylene group represented by the formula (I) include hydrocarbon arylene groups such as a phenylene group, a naphthylene group, a biphenylene group, and a fluorenediyl group, and heteroarylene groups such as pyridinediyl, quinoxalinediyl, and thiophenediyl, but are not limited to these.

[0114] In addition, in the general formula (S3), Y ３ and Y ４From the viewpoint of forming a phase-separated structure, the nonionic segment is preferably an aromatic polyether ketone polymer, since the nonionic segment is a ketone group or a protecting group that can be derived to a ketone group, and the block copolymer has crystallinity and is likely to form a phase-separated structure.

[0115] The structure represented by the above general formula (S3) preferably contains a structure represented by the following general formula (P2) from the viewpoint of raw material availability, and among these, it is more preferable that it contains a structural unit represented by the following general formula (S4) from the viewpoint of mechanical durability, dimensional stability, and physical durability due to crystallinity.

[0116]

[0117] In formulae (P2) and (S4), Y ３ and Y ４ each independently represents a ketone group or a protecting group that can be derivatized to a ketone group. * represents a bond to general formulae (P2) and (S4) or other structural units.

[0118] The content of the structure represented by 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 viewpoints of mechanical durability, dimensional stability, and physical durability.

[0119] Preferred examples of the protecting group that can be derived into a ketone group include those containing at least one selected from the following general formulae (P3) and (P4).

[0120]

[0121] (In the general formulas (P3) and (P4), Ar １１ ~Ar １４ represents any divalent arylene group, R １ and R ２ is at least one group selected from H and alkyl groups, R ３ represents any alkylene group, and each may represent two or more types of groups. The groups represented by general formulas (P3) and (P4) may be optionally substituted.) R in general formula (P3) １ and R２ In terms of stability, R is more preferably an alkyl group, even more preferably an alkyl group having 1 to 6 carbon atoms, and most preferably an alkyl group having 1 to 3 carbon atoms. ３ From the viewpoint of stability, R is more preferably an alkylene group having 1 to 7 carbon atoms, and most preferably an alkylene group having 1 to 4 carbon atoms. ３ Specific examples of the group include -CH ２ CH ２ -, -CH(CH ３ ) CH ２ -, -CH(CH ３ ) CH(CH ３ ) -, -C(CH ３ ) ２ CH ２ -, -C(CH ３ ) ２ CH (CH ３ ) -, -C(CH ３ ) ２ O (CH ３ ) ２ -, -CH ２ CH ２ CH ２ -, -CH ２ C(CH ３ ) ２ CH ２ - and the like, but are not limited to these.

[0122] Ar in the general formulae (P3) and (P4) １１ ~Ar １４ The organic group preferably used as Ar in the general formula (P4) is a phenylene group, a naphthylene group, or a biphenylene group. These may be optionally substituted. As the aromatic polyether polymer, the Ar in the general formula (P4) is preferably used because of its solubility and availability as a raw material. １３ and Ar １４ are more preferably both phenylene groups, and most preferably Ar １３ and Ar １４ are both p-phenylene groups.

[0123] Here, a method for protecting the ketone moiety with a ketal includes reacting 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 produced by reacting the ketone precursor 4,4'-dihydroxybenzophenone with a monofunctional and / or difunctional alcohol, or a solvent such as an aliphatic or aromatic hydrocarbon, in the presence of an acid catalyst such as hydrogen bromide. The alcohol is an aliphatic alcohol having 1 to 20 carbon atoms.

[0124] An improved method for preparing ketal monomers involves reacting the ketone precursor 4,4'-dihydroxybenzophenone with a difunctional alcohol in the presence of an alkyl orthoester and a solid catalyst.

[0125] The method for deprotecting at least a portion of the ketone moiety protected with a ketal to obtain a ketone moiety is not particularly limited. The deprotection reaction can be carried out in the presence of water and an acid under heterogeneous or homogeneous conditions. However, from the viewpoints of mechanical strength, physical durability, and solvent resistance, a method in which the product is formed into a membrane or the like and then subjected to an acid treatment is more preferred. Specifically, the formed membrane can be deprotected by immersing it in an aqueous hydrochloric acid solution or an aqueous sulfuric acid solution, and the concentration of the acid and the temperature of the aqueous solution can be appropriately selected.

[0126] The weight ratio of the acidic aqueous solution required to the polymer is preferably 1 to 100 times, although larger amounts 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. Suitable acid catalysts include strong mineral acids such as hydrochloric acid, nitric acid, fluorosulfonic acid, sulfuric acid, etc., and strong organic acids such as p-toluenesulfonic acid, trifluoromethanesulfonic acid, etc. The amounts of acid catalyst and excess water, reaction pressure, etc. can be appropriately selected depending on the polymer film thickness, etc.

[0127] For example, in the case of a film having a thickness of 50 μm, it is possible to easily deprotect almost the entire amount 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. It is also possible to deprotect most of the protecting groups by immersing it in a 1N hydrochloric acid solution at 25° C. for 24 hours. However, the deprotection conditions are not limited to these, and deprotection with an acidic gas, organic acid, or the like, or by heat treatment may also be used.

[0128] Even when the aromatic polyether polymer contains a bonding type other than an ether bond, such as a direct bond, the position of the protecting group to be introduced is preferably the aromatic ether polymer portion from the viewpoint of improving processability.

[0129] Specifically, for example, aromatic polyether polymers containing structural units represented by the general formulae (P3) and (P4) can be synthesized by using compounds represented by the following general formulae (P3-1) and (P4-1), respectively, as aromatic diphenol compounds and subjecting them to an aromatic nucleophilic substitution reaction with an aromatic active dihalide compound. The structural units represented by the general formulae (P3) and (P4) may be derived from either an aromatic diphenol compound or an aromatic active dihalide compound, but it is more preferable to use those derived from an aromatic diphenol compound in consideration of the reactivity of the monomer.

[0130]

[0131] (In the general formulas (P3-1) and (P4-1), Ar １１ ~Ar １４ represents any divalent arylene group, R １ and R ２ is at least one group selected from H and alkyl groups, R ３ represents any alkylene group. The compounds represented by general formula (P3-1) and general formula (P4-1) may be optionally substituted.) The above describes preferred protecting groups.

[0132] [Detailed Description of Block Copolymer] In the block copolymer constituting the polymer electrolyte material of the present invention, both the ionic segment and the nonionic segment are preferably aromatic polyether polymers, and more preferably aromatic polyether ketone polymers. In such block copolymers, 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 both segments, the density of sulfonic acid groups, etc.

[0133] For example, the IEC of the block copolymer can be adjusted by controlling the density of the sulfonic acid groups in the ionic segment and the content of the ionic segment in the block copolymer.

[0134] Furthermore, for example, the saturated crystallinity and heat of crystallization of the block copolymer can be adjusted by adjusting the molecular weight of the nonionic segment and the content of the nonionic segment in the block copolymer. Specifically, by setting the number average molecular weight of the nonionic segment to 15,000 or more, the saturated crystallinity and heat of crystallization of the block copolymer can be increased to desired ranges. That is, the nonionic segment constituting the block copolymer of the present invention is more preferably an aromatic polyether ketone polymer having a number average molecular weight of 15,000 or more. In particular, the block copolymer constituting the polymer electrolyte material of the present invention preferably contains an ionic segment containing a structural unit represented by the above general formula (S1) and a nonionic segment containing a structural unit represented by the above general formula (S3).

[0135] When the nonionic segment contains a constituent unit represented by general formula (S3), it is a crystalline segment, and by controlling the molecular weight of this nonionic segment and the content in the block copolymer, it is possible to adjust the saturated crystallinity and heat of crystallization to the desired level.

[0136] A block copolymer containing a nonionic segment containing a structural unit represented by general formula (S3) can be produced, for example, by molding a block copolymer precursor in which a protecting group has been introduced into at least the nonionic segment, and then deprotecting at least a portion of the protecting group contained in the molded product. Block copolymers tend to have poorer processability than random copolymers due to crystallization of the polymer that has formed domains, so it is preferable to introduce a protecting group into at least the nonionic segment to improve processability, and it is also preferable to introduce a protecting group into the ionic segment if processability is poor.

[0137] The block copolymer constituting the polymer electrolyte material of the present invention has a phase-separated structure. That is, in the block copolymer of the present invention having both ionic segments and nonionic segments, the hydrophilic domains formed by aggregation of the ionic segments have a locally high ionic group concentration and therefore exhibit excellent proton conductivity. The hydrophobic domains formed by aggregation of the nonionic segments have strong intermolecular interactions due to crystallinity and therefore exhibit excellent dimensional stability.

[0138]

[0023] When both the ionic segment and the nonionic segment constituting the block copolymer are aromatic polyether polymers, preferably aromatic polyether ketone polymers, a phase-separated structure is easily formed. Furthermore, from the above viewpoint, the block copolymer of the present invention preferably contains an ionic segment containing a structural unit represented by the general formula (S1) above and a nonionic segment containing a structural unit represented by the general formula (S3) above.

[0139] Furthermore, the block copolymer constituting the polymer electrolyte material of the present invention preferably contains one or more linker moieties connecting the ionic segments and the nonionic segments. Such a block copolymer is more preferred because it facilitates the formation of a bicontinuous or lamellar phase-separated structure.

[0140] The linker is defined as a moiety that connects an ionic segment and a nonionic segment and has a chemical structure different from that of the ionic segment or the nonionic segment.

[0141] The linker functions to link different segments while suppressing randomization of the copolymer due to ether exchange reactions, segment cleavage, and other side reactions that may occur during copolymer synthesis. Therefore, by using a compound that provides such a linker as a raw material, a block copolymer 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.

[0142] 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 constituting the polymer electrolyte material of the present invention, the IEC, saturated crystallinity, heat of crystallization, and average period size of the phase-separated structure of the block copolymer can be adjusted to the desired ranges described above. For example, from the viewpoint of adjusting the IEC and average period size of the phase-separated structure to the desired ranges, 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 saturated crystallinity, heat of crystallization, and average period size of the phase-separated structure to the desired ranges, 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.

[0143] In order to increase the number average molecular weight of the ionic segment relatively, for example, to increase the number average molecular weight to 45,000 or more, it is preferable to link the structural units in the ionic segment with a linker. The use of a linker makes it relatively easy to synthesize a long-chain polymer. Examples of linkers include, but are not limited to, decafluorobiphenyl, hexafluorobenzene, 4,4'-difluorodiphenyl sulfone, and 2,6-difluorobenzonitrile.

[0144] Furthermore, in the block copolymer constituting the polymer electrolyte material of the present invention, when the number average molecular weight of the ionic segment is Mn1 and the number average molecular weight of the nonionic segment is Mn2, it is preferable that the block copolymer satisfy the following formula 1, and more preferably the following formula 2. Such a block copolymer is preferable from the viewpoint of adjusting the IEC, heat of crystallization, and average periodic size of the phase separation structure to the aforementioned ranges.

[0145] 1.7≦Mn1 / Mn2≦7.0 (Formula 1) 2.0≦Mn1 / Mn2≦5.0 (Formula 2).

[0146] In particular, it is preferable that the number average molecular weight (Mn2) of the nonionic segment is 15,000 or more and satisfies the above formulas 1 and 2, from the viewpoint of adjusting the IEC, saturated crystallinity, heat of crystallization, and average periodic size of the phase separation structure within the above-mentioned ranges.

[0147] Specific examples of methods for synthesizing the block copolymer constituting the polymer electrolyte material of the present invention are given below, although the present invention is not limited to these.

[0148] Each segment in the block copolymer constituting the polymer electrolyte material of the present invention is preferably synthesized by an aromatic nucleophilic substitution reaction due to ease of processing. The aromatic nucleophilic substitution reaction is a method in which a monomer mixture of a dihalide compound and a diol compound is reacted in the presence of a basic compound. Polymerization can be carried out at a temperature ranging from 0 to 350°C, with temperatures of 50 to 250°C being preferred. The reaction can be carried out without a solvent, but is preferably carried out in a solvent. Examples of solvents that can be used include aprotic polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolidinone, and hexamethylphosphontriamide, but are not limited to these. Any solvent that can be used as a stable solvent in an aromatic nucleophilic substitution reaction can be used. These organic solvents may be used alone or in a mixture of two or more.

[0149] Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, but any basic compound can be used as long as it can convert diols into active phenoxide structures. It is also preferable to add a crown ether such as 18-crown-6 to enhance the nucleophilicity of the phenoxide. Crown ethers are preferably used because they can coordinate with the sodium ion or potassium ion of the sulfonic acid group and improve the solubility of the sulfonate moiety of the monomer or polymer in organic solvents.

[0150] In aromatic nucleophilic substitution reactions, water may be produced as a by-product. In this case, water can be removed from the system as an azeotrope by adding toluene or other solvents to the reaction system, regardless of the polymerization solvent. A water-absorbing agent such as a molecular sieve can also be used to remove water from the system.

[0151] The block copolymer constituting the polymer electrolyte material of the present invention can be produced by synthesizing a block copolymer precursor and then deprotecting at least a portion of the protecting groups contained in the precursor. The method for producing the block copolymer and block copolymer precursor of the present invention preferably includes at least the following steps (1) and (2). By including these steps, improved mechanical durability and durability can be achieved through increased molecular weight, and the alternate introduction of both segments can produce a block copolymer with excellent low-humidity proton conductivity in which the phase-separated structure and domain size are strictly controlled.

[0152] Step (1): A step of introducing linker moieties into both ends of one of an ionic segment having -OM groups (M represents a hydrogen atom, a metal cation, or an ammonium cation) at both ends and a nonionic segment having -OM groups at both ends by reacting the -OM groups at both ends of the segment with a linker compound. Step (2): A step of producing a block copolymer or a block copolymer precursor having an ionic segment and a nonionic segment by polymerizing the linker moieties at both ends of the segment into which the linker moieties have been introduced, synthesized in step (1), with the -OM groups at both ends of the other segment.

[0153] Specific examples of the segment represented by general formula (S1) having -OM groups at both ends and the segment represented by general formula (S2) having -OM groups at both ends include segments having structures represented by the following general formulae (H3-1) and (H3-2), respectively. Furthermore, examples of the structures obtained after reacting the segments having structures represented by general formulae (H3-1) and (H3-2) with a halide linker include structures represented by the following general formulae (H3-3) and (H3-4), respectively. However, the present invention is not limited to these.

[0154]

[0155] In the above general formulae (H3-1) to (H3-4), N １ , N ２ , N ３ , N４ each independently represents an integer of 1 to 200.

[0156] When the ionic segment has a linker, specific examples of the ionic segment having a linker moiety introduced therein obtained by the above step (1) include structures represented by the following general formulae (H3-1L) and (H3-3L), although the present invention is not limited thereto.

[0157]

[0158] In the above general formulae (H3-1L) to (H3-3L), N5 and N6 each independently represent an integer of 1 to 200.

[0159] In 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 these can be used without limitation. Furthermore, these general formulas are inserted to aid the reader's understanding, and do not necessarily accurately represent the chemical structure, exact composition, arrangement, position, number and molecular weight of the polymerization components of the polymer, and are not limited to these.

[0160] Furthermore, in general formulas (H3-1) to (H3-4), (H3-1L), and (H3-3L), a ketal group is introduced as a protecting group into each segment, but in the present invention, a protecting group may be introduced into a component that is highly crystalline and has low solubility. Therefore, the ionic segment does not necessarily require a protecting group, and from the viewpoint of durability and dimensional stability, those without a protecting group can also be preferably used.

[0161] [Polymer Electrolyte Molded Body] The electrolyte material of the present invention is suitable as a polymer electrolyte molded body. Here, a polymer electrolyte molded body refers to a molded body containing the electrolyte material of the present invention. Such polymer electrolyte molded bodies can take various forms depending on the application, such as membranes (including films and film-like bodies), as well as plates, fibers, hollow fibers, particles, blocks, microporous bodies, coatings, and foams. Among these, membranes are preferred because they are adaptable to a wide range of applications. Hereinafter, a membrane-type polymer electrolyte molded body will be referred to as a "molded electrolyte membrane." Hereinafter, an electrolyte membrane will be described as a representative example of a polymer electrolyte molded body, but the present invention is not limited thereto.

[0162] Examples of methods for producing a cast electrolyte membrane include a method of forming a membrane from a solution state at a stage where the electrolyte material has a protecting group such as ketal, and a method of forming a membrane from a molten state. The former method includes, for example, dissolving the electrolyte material in a solvent such as N-methyl-2-pyrrolidone, casting the solution onto a glass plate or a polyethylene terephthalate film (hereinafter, referred to as a PET film), and then removing the solvent to form a membrane.

[0163] The solvent used for membrane formation may be any solvent that dissolves the electrolyte material and can be subsequently removed. Examples of suitable solvents include aprotic polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, 1,3-dimethyl-2-imidazolidinone, and hexamethylphosphontriamide; 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 are preferred because they have the highest solubility. Furthermore, adding a crown ether such as 18-crown-6 is also suitable to enhance the solubility of the ionic segment.

[0164] The electrolyte material of the present invention can be converted into a molded electrolyte membrane by, for example, forming a membrane from the electrolyte material using the above-described method, and then deprotecting at least a portion of the sites protected by protecting groups. For example, when the protecting groups include ketal sites, at least a portion of the ketone sites protected by the ketal sites is deprotected to form ketone sites. This method enables solution membrane formation of poorly soluble block copolymers, thereby achieving both proton conductivity and mechanical and physical durability.

[0165] Alternatively, after forming a membrane in a state in which the ionic groups contained therein form salts with alkali metal or alkaline earth metal cations, a step of exchanging the alkali metal or alkaline earth metal cations with protons may be carried out. This step is preferably a step of contacting the formed membrane with an acidic aqueous solution, and more preferably a step of immersing the formed membrane in the acidic aqueous solution. In this step, protons in the acidic aqueous solution are substituted with cations ionically bonded to the ionic groups, and residual water-soluble impurities, residual monomers, solvents, residual salts, etc. are simultaneously removed.

[0166] The acidic aqueous solution is not particularly limited, but it is preferable to use sulfuric acid, hydrochloric acid, nitric acid, acetic acid, trifluoromethanesulfonic acid, methanesulfonic acid, phosphoric acid, citric acid, etc. The temperature, concentration, etc. of the acidic aqueous solution should also be determined appropriately, but from the viewpoint of productivity, it is preferable to use an aqueous sulfuric acid solution of 3 mass % or more and 30 mass % or less at a temperature of 0° C. or more and 80° C. or less.

[0167] The thickness of the electrolyte membrane in the present invention is preferably 1 μm or more, more preferably 2 μm or more, and particularly preferably 3 μm or more from the viewpoints of mechanical durability and physical durability, while 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.

[0168] The electrolyte membrane may also contain additives such as crystallization nucleating agents, plasticizers, stabilizers, antioxidants, and release agents that are commonly used in polymer compounds, within the scope of the present invention.

[0169] The electrolyte membrane may contain various polymers, elastomers, fillers, fine particles, various additives, etc., to improve mechanical strength, thermal stability, processability, etc., within the range that does not adversely affect the above-mentioned properties. The electrolyte membrane may also be reinforced with a microporous membrane, nonwoven fabric, mesh, etc.

[0170] The electrolyte membrane can be used in a variety of applications. For example, it can be used in medical applications such as artificial skin, filtration applications, ion exchange resin applications such as chlorine-resistant reverse osmosis membranes, various structural materials, electrochemical applications, humidifying membranes, antifogging membranes, antistatic membranes, oxygen-removing membranes, solar cell membranes, and gas barrier membranes. Among these, it is particularly suitable for various electrochemical applications. Examples of electrochemical applications include solid polymer fuel cells, redox flow batteries, water electrolysis devices, chloroalkali electrolysis devices, electrochemical hydrogen pumps, and water electrolysis hydrogen generation devices.

[0171] In polymer electrolyte fuel cells, electrochemical hydrogen pumps, and water electrolysis hydrogen generators, a cast electrolyte membrane is used in a structure in which a catalyst layer, an electrode substrate, and a separator are sequentially laminated on both sides of the cast electrolyte membrane. A cast electrolyte membrane with a catalyst layer laminated on both sides (i.e., a structure of catalyst layer / cast electrolyte membrane / catalyst layer) is called a catalyst-coated electrolyte membrane (CCM), and a cast electrolyte membrane with a catalyst layer and a gas diffusion substrate sequentially laminated on both sides of the cast electrolyte membrane (i.e., a structure of gas diffusion substrate / catalyst layer / cast electrolyte membrane / catalyst layer / gas diffusion substrate) is called a membrane electrode assembly (MEA). The electrolyte material of the present invention is particularly suitable as the cast electrolyte membrane that constitutes such a CCM and MEA.

[0172] The electrolyte membrane can be produced, for example, by casting an electrolyte solution prepared by dissolving or dispersing an electrolyte material in a suitable solvent onto a support substrate (such as a glass plate or a PET film) and then drying. The electrolyte membrane thus obtained is optionally acid-treated, washed with water, and dried. In the drying step, the crystallinity of the electrolyte membrane can be increased by drying at a temperature equal to or higher than the glass transition temperature of the electrolyte material, or by heating at the above temperature after drying. The crystallinity of the electrolyte membrane can be adjusted by controlling the heating temperature and heating time.

[0173] Furthermore, in the hot pressing step when producing the above-described catalyst-coated electrolyte membrane (CCM), the crystallinity of the formed electrolyte membrane can be adjusted by controlling the heating temperature and pressing pressure.

[0174] The present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples. The measurement methods used in these examples are shown below. In the following measurement methods, when it was difficult to measure using a block copolymer or there were concerns about measurement accuracy, the following electrolyte membranes were used as samples instead of block copolymers.

[0175] <Preparation of Electrolyte Membrane (Specimen)> A 25 wt % N-methylpyrrolidone (NMP) solution containing the block copolymer was pressure-filtered using a glass fiber filter, then cast onto a glass substrate, dried at 100°C for 4 hours, and then heat-treated at 150°C for 10 minutes under nitrogen to obtain a 10 μm-thick membrane. This membrane was then immersed in a 10 wt % aqueous sulfuric acid solution at 95°C for 24 hours to undergo proton substitution and deprotection reactions, followed by immersion in a large excess of pure water for 24 hours, thorough washing, and drying to obtain an electrolyte membrane. The crystallinity of this electrolyte membrane (specimen) was 0% as determined by wide-angle X-ray diffraction (XRD).

[0176] (1) Molecular Weight of Polymer The number average molecular weight and weight average molecular weight of the polymer were measured by GPC. Using an HLC-8022 GPC (manufactured by Tosoh Corporation) as an integrated UV detector and differential refractometer, a TSKgel Guard Column Super H-H (inner diameter 4.6 mm, length 3.5 cm) (manufactured by Tosoh Corporation) as a guard column, and two TSKgel Super HM-H (inner diameter 6.0 mm, length 15 cm) (manufactured by Tosoh Corporation) as GPC columns, measurements were performed in N-methyl-2-pyrrolidone solvent (N-methyl-2-pyrrolidone solvent containing 10 mmol / L of 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, and the number average molecular weight and weight average molecular weight were calculated in terms of standard polystyrene.

[0177] (2) Ion Exchange Capacity (IEC) was measured by the neutralization titration method described in 1) to 4) below. Measurements were performed three times, and the average value was calculated. 1) After proton exchange and thorough washing with pure water, the block copolymer was wiped dry and then vacuum-dried at 100°C for at least 12 hours to determine the dry weight. 2) 50 mL of a 5 wt% aqueous solution of sodium sulfate was added to the block copolymer, and the mixture was allowed to stand for 12 hours to perform ion exchange. 3) The resulting sulfuric acid was titrated using a 0.01 mol / L aqueous solution of sodium hydroxide. 0.1 w / v% commercially available phenolphthalein solution for titration was added as an indicator, and the point at which the solution turned a light reddish-purple color was defined as the endpoint. 4) IEC was calculated using the following formula: IEC (meq / g) = [concentration of aqueous sodium hydroxide solution (mmol / mL) × amount added (mL)] / dry weight of sample (g).

[0178] (3) Measurement of Glass Transition Temperature Tg 10 mg of electrolyte material was pre-dried in a DSC device at 110 ° C for 3 hours, and then the sample was heated to 200 ° C under the following conditions without removing it from the DSC device, and temperature-modulated differential scanning calorimetry (TMS) was performed during the heating stage. The glass transition temperature is defined as the midpoint between the two intersections obtained from two extensions of the baseline and the tangent to the endothermic curve. DSC device: DSC7000X (Hitachi High-Tech Corporation) Measurement temperature range: 30 ° C to 200 ° C Temperature control: AC temperature control Heating rate: 2 ° C / min Amplitude: ± 3 ° C Applied frequency: 0.02 Hz Sample pan: Aluminum crimp pan Measurement and pre-drying atmosphere: Nitrogen 100 mL / min Pre-drying: 110 ° C, 3 hours.

[0179] (4) Measurement of Saturated Crystallinity An electrolyte membrane (specimen) was cut into a 5 cm x 5 cm square, and this specimen was sandwiched between two polyimide films (50 μm thick). This specimen was then hot-pressed in a hot press at a temperature equal to the glass transition temperature of each block copolymer plus 5°C and a pressure of 4.5 MPa for 5 minutes, and the crystallinity was then measured. This procedure was repeated, and the crystallinity at which the crystallinity no longer changed was taken as the saturated crystallinity. The method for measuring crystallinity is described below. <Crystallization by Wide-Angle X-ray Diffraction (XRD)> The hot-pressed specimen was placed in a diffractometer, and X-ray diffraction measurement was performed under the following conditions. X-ray diffractometer: RINT2500V manufactured by Rigaku Corporation X-ray: Cu-Kα X-ray output: 50 kV-300 mA Optical system: focusing optical system Scan speed: 2θ=2° / min Scan method: 2θ-θ Scan range: 2θ=5 to 60° Slits: divergence slit -½°, receiving slit -0.15 mm, scattering slit -½° The X-ray diffraction measurement results were subjected to profile fitting to separate each component, and the diffraction angle and integrated intensity of each component were determined. The crystallinity was calculated from the obtained crystalline peak and integrated intensities of the amorphous halo according to the following general formula (s2).

[0180] Crystallinity (%)=(sum of integrated intensities of all crystalline peaks) / (sum of integrated intensities of all crystalline peaks and amorphous halo)×100 (s2).

[0181] (5) Crystallization Calorimetry by Differential Scanning Calorimetry (DSC) 10 mg of electrolyte membrane (specimen) was pre-dried in a DSC apparatus at 110°C for 3 hours, and then, without removing the specimen from the DSC apparatus, the temperature was raised to 200°C under the following conditions to perform temperature-modulated differential scanning calorimetry during the temperature-raising stage: Measurement temperature range: 30°C to 200°C Temperature control: AC temperature control Heating rate: 2°C / min Amplitude: ±3°C Applied frequency: 0.02 Hz Sample pan: Aluminum crimp pan Measurement and pre-drying atmosphere: Nitrogen 100 mL / min

[0182] (6) Observation of Phase Separation Structure Using a Transmission Electron Microscope (TEM) The phase separation structure was confirmed using an electrolyte membrane (specimen). A sample piece was immersed in a 2 wt % aqueous solution of lead acetate as a staining agent and left at 25°C for 72 hours. The stained sample was removed and embedded in epoxy resin. An 80 nm thin section was cut using an ultramicrotome at room temperature, and the resulting thin section was collected on a Cu grid and subjected to TEM observation. Observation was performed at an accelerating voltage of 100 kV, and images were taken at a magnification of 10,000 to 100,000 times. The magnification was set appropriately depending on the size of the phase separation structure. The equipment used was an HT7700 (manufactured by Hitachi High-Tech Corporation).

[0183] In addition, the TEM image was subjected to fast Fourier transform (FFT), and the spatial frequency in the TD and ZD directions was measured from the resulting ring-shaped FFT pattern, from which the periodic size of the phase separation structure was calculated. The spatial frequency was measured as the distance from the center of the image to the center of the ring thickness. FFT and length measurements were performed using a Digital Micrograph (manufactured by Gatan).

[0184] (7) Observation of Phase Separation Structure by Transmission Electron Microscope (TEM) Tomography The thin section sample prepared by the method described in (6) above was mounted on a collodion film and observed under the following conditions. Apparatus: Field Emission Electron Microscope (HRTEM) JEM 2100F manufactured by JEOL Ltd. Image Acquisition: DigitalMicrograph (manufactured by Gatan) System: Marker Method Acceleration Voltage: 200 kV Imaging Magnification: 30,000x Tilt Angle: +60° to -62° Reconstruction Resolution: 0.71 nm / pixel The marker method was applied for the three-dimensional reconstruction process. Au colloidal particles applied to the collodion film were used as alignment markers for performing the three-dimensional reconstruction. Using the marker as a reference, the sample was tilted in 1° increments in the range of +61° to -62°, and TEM images were taken. A total of 124 TEM images were obtained from a series of successive tilt images, and CT reconstruction processing was performed based on these images to observe the three-dimensional phase separation structure.

[0185] (8) Proton Conductivity Isopropanol-based carbon paste (G7711, manufactured by EM Japan Co., Ltd.) was applied to the platinum electrode of the cell, and a diffusion layer electrode (ELAT GDL 140-HT, manufactured by E-TEK Corporation) cut to 18 mm x 6 mm was attached. An electrolyte membrane (specimen) cut to a 30 mm x 8 mm rectangle was placed between the cell's electrodes, and the cell was fastened at 1 MPa and housed in the chamber of the MTS740. The proton resistance of the electrolyte membrane in the membrane thickness direction was evaluated using an MTS740 membrane resistance measurement system (manufactured by Scribner). The MTS740 housed the cell in a temperature-controlled chamber, and air gas was supplied to the chamber via a humidifier using a mass flow controller. The cell was connected to a frequency response analyzer PSM1735 (manufactured by Newtons 4th), and resistance could be measured by sweeping an AC signal from 1 MHz to 1 kHz.

[0186] The MTS740 and PSM1735 were connected to a PC and controlled by software. After setting the chamber temperature to 80°C, 90% RH air gas was supplied and held for 1 hour to thoroughly wet the electrolyte membrane. Then, 20% RH air was supplied to dry the membrane, and 30% RH air was supplied and held for 30 minutes, after which the resistance was measured. The frequency was swept from 1 MHz to 1 kHz. Then, 80% RH air was supplied and held for 30 minutes, after which the resistance was measured in the same manner. A Cole-Cole plot was created from the measured resistance data. Because the frequency band around 1 MHz is affected by the inductance component of the cable connecting the cell and PSM1735, the resistance value (Ω) was taken as the real axis value at 200 kHz, where this effect is least significant. The proton conductivity when 30% RH air was supplied was defined as low-humidification proton conductivity, and the proton conductivity when 80% RH air was supplied was defined as high-humidification proton conductivity. Using the measured resistance value, the proton conductivity was calculated according to the following formula: Proton conductivity (mS / cm) = 1 / (resistance value (Ω) × active area (cm ２ ) / sample thickness (cm)).

[0187] The low humidified proton conductivity is preferably 0.85 mS / cm or more, more preferably 0.90 mS / cm or more, even more preferably 1.00 mS / cm or more, and particularly preferably 1.10 mS / cm or more. The high humidified proton conductivity is preferably 9.00 mS / cm or more, more preferably 9.50 mS / cm or more, even more preferably 11.00 mS / cm or more, and particularly preferably 13.00 mS / cm or more.

[0188] (9) Wet-Dry Dimensional Change Rate The electrolyte membrane (specimen) was cut into a 3 mm x 20 mm rectangle to prepare a sample piece. The sample piece was placed in the sample holder of a thermomechanical analyzer TMA / SS6100 (manufactured by Hitachi High-Tech Science Corporation) equipped with a temperature and humidity control furnace, with the long side of the sample piece facing the measurement direction, and a stress of 20 mN was applied. The sample was allowed to stand at 23°C and 50% RH in the furnace for 1 hour, and the length of the sample piece was designated as the zero point. The temperature inside the furnace was fixed at 23°C, and the humidity was adjusted to 30% RH (dry conditions) over 30 minutes and held for 20 minutes. Next, the humidity was adjusted to 90% RH (humidified conditions) over 30 minutes. This wet-dry 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 at the 10th cycle was designated the wet-dry 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.

[0189] [Synthesis of Polymer] The structures of the compounds obtained in the following synthesis examples are as follows: １ The purity was confirmed by H-NMR, and quantitative analysis was performed by capillary electrophoresis (organic substances) and ion chromatography (inorganic substances).

[0190] Synthesis Example 1 (Synthesis of 2,2-bis(4-hydroxyphenyl)-1,3-dioxolane (K-DHBP) represented by the following formula (G1)) A 500 mL flask equipped with a stirrer, thermometer, and distillation tube was charged with 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 form a solution. The mixture was then stirred and kept at 78 to 82°C for 2 hours. The internal temperature was then gradually raised to 120°C and maintained at 120°C until the distillation of methyl formate, methanol, and trimethyl orthoformate completely stopped. After cooling this reaction solution to room temperature, it was diluted with ethyl acetate. The organic layer was washed with 100 mL of a 5% aqueous potassium carbonate solution and separated, and the solvent was then evaporated. 80 mL of dichloromethane was added to the residue to precipitate crystals, which were filtered and dried to obtain 52.0 g of 2,2-bis(4-hydroxyphenyl)-1,3-dioxolane with a purity of 99.9%.

[0191]

[0192] Synthesis Example 2 (Synthesis of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone represented by the following formula (G2)) 109.1 g of 4,4'-difluorobenzophenone (Aldrich reagent) was dissolved in fuming sulfuric acid (50% SO ３ The resulting mixture was reacted in 150 mL of ethanol (Wako Pure Chemical Industries, Ltd.) at 100°C for 10 hours. The resulting mixture was then poured little by little into a large amount of water, neutralized with NaOH, and 200 g of sodium chloride (NaCl) was added to precipitate the product. The resulting precipitate was filtered and recrystallized from an aqueous ethanol solution to obtain disodium-3,3'-disulfonate-4,4'-difluorobenzophenone. The purity was 99.3%.

[0193]

[0194] Synthesis Example 3 (Synthesis of 3,3'-disulfonic acid sodium salt-4,4'-difluorodiphenyl sulfone represented by the following formula (G3)) 109.1 g of 4,4-difluorodiphenyl sulfone (Aldrich reagent) was dissolved in fuming sulfuric acid (50% SO ３ ) (Wako Pure Chemical Industries, Ltd. Reagents) and reacted at 100°C for 10 hours. Thereafter, the mixture was poured little by little into a large amount of water, neutralized with NaOH, and then 200 g of salt was added to precipitate the synthesized product. The resulting precipitate was filtered and recrystallized with an aqueous ethanol solution to obtain 3,3'-disulfonic acid sodium salt-4,4'-difluorodiphenylsulfone. The purity was 99.3%.

[0195]

[0196] [Electrolyte Material (I)] [Example 1] <Synthesis of Nonionic Oligomer a1 Represented by the General Formula (G4) Below> 16.59 g of potassium carbonate (Aldrich reagent, 120 mmol), 25.83 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, and 21.38 g of 4,4'-difluorobenzophenone (Aldrich reagent, 98 mmol) were placed in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere in the reactor with nitrogen, 300 mL of N-methylpyrrolidone (NMP) and 100 mL of toluene were added. After dehydration at 150°C, the temperature was raised to remove the toluene, and polymerization was carried out at 170°C for 3 hours. Purification by reprecipitation into a large amount of methanol yielded nonionic oligomer a1 with a terminal hydroxy group. The number average molecular weight of the terminal hydroxy group of this nonionic oligomer a1 was 20,000.

[0197] A 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 1.1 g of potassium carbonate (Aldrich reagent, 8 mmol) and 20.0 g (1 mmol) of the terminal hydroxy group of the nonionic oligomer a1. After replacing the atmosphere inside the flask with nitrogen, 100 mL of NMP and 30 mL of toluene were added, and the mixture was dehydrated at 100°C and then heated to remove the toluene. Furthermore, 1.1 g of hexafluorobenzene (Aldrich reagent, 6 mmol) was added, and the reaction was carried out at 105°C for 12 hours. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol, yielding nonionic oligomer a1 (terminal: fluoro group) represented by the following general formula (G4). The number average molecular weight of this nonionic oligomer a1 was 21,000. In general formula (G4), m represents an integer of 1 or greater.

[0198]

[0199] <Synthesis of ionic oligomer a2 represented by the following general formula (G5)> 27.64 g of potassium carbonate (Aldrich reagent, 200 mmol), 12.91 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.31 g of 4,4'-biphenol (Aldrich reagent, 50 mmol), 41.60 g (98.5 mmol) of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 26.40 g of 18-crown-6 (100 mmol, Wako Pure Chemical Industries) were placed in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere in the reactor with nitrogen, 300 mL of NMP and 100 mL of toluene were added, and the mixture was dehydrated at 150°C, heated to remove toluene, and then polymerized at 170°C for 6 hours. The resulting product was purified by reprecipitation with a large amount of isopropyl alcohol to obtain an ionic oligomer a2 (terminal: OM group) represented by the following general formula (G5). The number average molecular weight of this ionic oligomer a2 was 45,000. In general formula (G5), M represents a hydrogen atom, Na, or K, and n represents an integer of 1 or greater.

[0200]

[0201] <Synthesis of Ionic Oligomer a2' Represented by General Formula (G6)> 0.56 g of potassium carbonate (Aldrich reagent, 400 mmol) and 49.0 g of ionic oligomer a2 were placed in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere inside the reactor with nitrogen, 500 mL of NMP was added. The contents were dissolved at 60°C, and then 19.8 g of a hexafluorobenzene / NMP solution (1 wt%) was added. The reaction was carried out at 80°C for 18 hours, yielding 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' was 90,000. In general formula (G6), M represents a hydrogen atom, Na, or K, and n represents an integer of 1 or greater.

[0202]

[0203] <Synthesis of Block Copolymer b1> The block copolymer b1 contains the above oligomer a2' as an ionic segment and the above oligomer a1 as a nonionic segment.

[0204] A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 49.0 g of ionic oligomer a2' and 7.65 g of nonionic oligomer a1, and NMP was added so that the total amount of oligomer charged was 7 wt%, and the reaction was carried out at 105 ° C. for 24 hours. Reprecipitation was carried out in a large amount of isopropyl alcohol / NMP mixed solution (weight ratio 2 / 1), and purification was carried out with a large amount of isopropyl alcohol to obtain block copolymer b1. The number average molecular weight of this block copolymer b1 was 170,000, and the weight average molecular weight was 410,000.

[0205] The saturated crystallinity of block copolymer b1 was 11.6%, the glass transition temperature was 157°C, and the IEC was 2.5 meq / g. The electrolyte membrane prepared using block copolymer b1 was confirmed to have a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed a continuous phase).

[0206] Example 2 Synthesis of Block Copolymer b2 The block copolymer b2 contains the above oligomer a2' as an ionic segment and the above oligomer a1 as a nonionic segment.

[0207] Block copolymer b2 was obtained in the same manner as in Example 1, except that the amount of nonionic oligomer a1 used was 5.4 g. The number average molecular weight of this block copolymer b2 was 180,000 and the weight average molecular weight was 430,000.

[0208] The saturated crystallinity of block copolymer b2 was 9.2%, the glass transition temperature was 160°C, and the IEC was 2.7 meq / g. The electrolyte membrane prepared using block copolymer b2 was confirmed to have a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed a continuous phase).

[0209] Example 3 Synthesis of Nonionic Oligomer a3 Represented by General Formula (G4) A terminal hydroxy compound of oligomer a3 was obtained in the same manner as in the synthesis of the terminal hydroxy compound of oligomer a1, except that the amount of 4,4'-difluorobenzophenone used was 21.45 g. The number average molecular weight of the terminal hydroxy compound of this oligomer a3 was 25,000.

[0210] A nonionic oligomer a3 (terminal: fluoro group) represented by general formula (G4) was obtained in the same manner as in the synthesis of oligomer a1, except that 25.0 g of the terminal hydroxyl group of oligomer a3 was used instead of the terminal hydroxyl group of oligomer a1. The number average molecular weight of this nonionic oligomer a3 was 26,000.

[0211] <Synthesis of Block Copolymer b3> The block copolymer b3 contains the above oligomer a2' as an ionic segment and the above oligomer a3 as a nonionic segment.

[0212] Block copolymer b3 was obtained in the same manner as block copolymer b1, except that nonionic oligomer a3 (12.3 g) was used instead of nonionic oligomer a1 (7.65 g). This block copolymer b3 had a number-average molecular weight of 160,000 and a weight-average molecular weight of 390,000.

[0213] The saturated crystallinity of block copolymer b3 was 15.6%, the glass transition temperature was 160°C, and the IEC was 2.1 meq / g. An electrolyte membrane prepared using block copolymer b3 was confirmed to have a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed a continuous phase).

[0214] Example 4 Synthesis of Nonionic Oligomer a5 Represented by General Formula (G4) A terminal hydroxy compound of oligomer a5 was obtained in the same manner as in the synthesis of the terminal hydroxy compound of oligomer a1, except that the amount of 4,4'-difluorobenzophenone used was 21.51 g. The number average molecular weight of the terminal hydroxy compound of oligomer a5 was 29,000.

[0215] A nonionic oligomer a5 (terminal: fluoro group) represented by general formula (G4) was obtained in the same manner as in the synthesis of oligomer a1, except that 29.0 g of the terminal hydroxy group of oligomer a5 was used instead of the terminal hydroxy group of oligomer a1. The number average molecular weight of this nonionic oligomer a5 was 30,000.

[0216] <Synthesis of ionic oligomer a4 represented by general formula (G5)> Ionic oligomer a4 was obtained in the same manner as in the synthesis of ionic oligomer a2, except that the amount of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone used was 41.38 g (98.0 mmol). This ionic oligomer a4 had a number average molecular weight of 35,000.

[0217] <Synthesis of Ionic Oligomer a4' Represented by General Formula (G7)> 0.56 g of potassium carbonate (Aldrich reagent, 400 mmol) and 37.16 g of ionic oligomer a4 were placed in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere inside the reactor with nitrogen, 400 mL of NMP was added. The contents were dissolved at 60°C, and then 11.4 g of a 2,6-difluorobenzonitrile / NMP solution (1 wt%) was added. The reaction was carried out at 80°C for 18 hours, yielding 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' was 70,000. In general formula (G7), M represents a hydrogen atom, Na, or K, and n represents an integer of 1 or greater.

[0218]

[0219] <Synthesis of Block Copolymer b4> The block copolymer b4 contains the above oligomer a4' as an ionic segment and the above oligomer a5 as a nonionic segment.

[0220] Block copolymer b4 was obtained in the same manner as block copolymer b1, except that ionic oligomer a4' (37.16 g) was used instead of ionic oligomer a2' (49.0 g) and nonionic oligomer a5 (12.39 g) was used instead of nonionic oligomer a1 (7.65 g). The number-average molecular weight of block copolymer b4 was 120,000, and the weight-average molecular weight was 360,000.

[0221] The saturated crystallinity of block copolymer b4 was 18.0%, the glass transition temperature was 160°C, and the IEC was 1.9 meq / g. An electrolyte membrane prepared using block copolymer b4 was confirmed to have a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed a continuous phase).

[0222] Example 5 Synthesis of Nonionic Oligomer a7 Represented by General Formula (G4) A terminal hydroxy compound of nonionic oligomer a7 was obtained in the same manner as in the synthesis of the terminal hydroxy compound of nonionic oligomer a1, except that the amount of 4,4'-difluorobenzophenone used was 21.27 g. The number average molecular weight of the terminal hydroxy compound of nonionic oligomer a7 was 16,000.

[0223] A nonionic oligomer a7 (terminal: fluoro group) represented by general formula (G4) was obtained in the same manner as in the synthesis of nonionic oligomer a1, except that 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). The number average molecular weight of this nonionic oligomer a7 was 17,000.

[0224] <Synthesis of Ionic Oligomer a6 Represented by General Formula (G5)> A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 27.64 g of potassium carbonate (Aldrich reagent, 200 mmol), 12.91 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.31 g of 4,4'-biphenol (Aldrich reagent, 50 mmol), and 41.85 g (99.1 mmol) of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2. After the atmosphere inside the reactor was replaced with nitrogen, 300 mL of dimethyl sulfoxide (DMSO) and 100 mL of toluene were added, and the mixture was dehydrated at 133°C, then heated to remove toluene, and polymerized at 150°C for 2 hours, then heated to 155°C, and polymerized for an additional 1 hour. The resulting product was purified by reprecipitation with a large amount of isopropyl alcohol to obtain an ionic oligomer a6 (terminal: OM group) represented by general formula (G5). The number average molecular weight of the ionic oligomer a6 was 56,000.

[0225] <Synthesis of Block Copolymer b5> The block copolymer b5 contains the above oligomer a6 as an ionic segment and the above oligomer a7 as a nonionic segment.

[0226] Block copolymer b5 was obtained in the same manner as block copolymer b1, except that 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). This block copolymer b5 had a number-average molecular weight of 140,000 and a weight-average molecular weight of 360,000.

[0227] The saturated crystallinity of block copolymer b5 was 13.5%, the glass transition temperature was 159°C, and the IEC was 2.1 meq / g. An electrolyte membrane prepared using block copolymer b5 was confirmed to have a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed a continuous phase).

[0228] Comparative Example 1 Synthesis of Nonionic Oligomer a9 Represented by General Formula (G4) A terminal hydroxy compound of nonionic oligomer a9 was obtained in the same manner as in the synthesis of the terminal hydroxy compound of nonionic oligomer a1, except that the amount of 4,4'-difluorobenzophenone used was 20.4 g. The number average molecular weight of the terminal hydroxy compound of nonionic oligomer a9 was 7,000.

[0229] A nonionic oligomer a9 (terminal: fluoro group) represented by general formula (G4) was obtained in the same manner as in the synthesis of nonionic oligomer a1, except that 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). The number average molecular weight of this nonionic oligomer a9 was 8,000.

[0230] <Synthesis of Ionic Oligomer a8 Represented by General Formula (G5)> Into a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap, 27.64 g of potassium carbonate (Aldrich reagent, 200 mmol), 12.91 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.31 g of 4,4'-biphenol (Aldrich reagent, 50 mmol), 41.47 g (98.2 mmol) of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 18- Crown-6 (26.40 g: 100 mmol, Wako Pure Chemical Industries) was placed in the reactor. After replacing the atmosphere with nitrogen, 300 mL of NMP and 100 mL of toluene were added, and the mixture was dehydrated at 150°C. The temperature was then raised to remove the toluene, and polymerization was carried out at 170°C for 6 hours. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol, yielding an ionic oligomer a8 (terminal: hydroxy group) represented by general formula (G5). The number average molecular weight of this ionic oligomer a8 was 42,000.

[0231] <Synthesis of Block Copolymer b6> Block copolymer b6 contains oligomer a8 as the ionic segment and oligomer a9 as the nonionic segment. Block copolymer b6 was obtained in the same manner as block copolymer b1, except that ionic group 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). The number average molecular weight of this block copolymer b6 was 140,000 and the weight average molecular weight was 400,000.

[0232] The saturated crystallinity of block copolymer b6 was 4.1%, the glass transition temperature was 157°C, and the IEC was 2.2 meq / g. An electrolyte membrane prepared using block copolymer b6 was confirmed to have a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed continuous phases).

[0233] Comparative Example 2 Synthesis of Nonionic Oligomer a11 Represented by General Formula (G4) A terminal hydroxy compound of nonionic oligomer a11 was obtained in the same manner as in the synthesis of the terminal hydroxy compound of nonionic oligomer a1, except that the amount of 4,4'-difluorobenzophenone used was 20.18 g. The number average molecular weight of the terminal hydroxy compound of this nonionic oligomer a11 was 5,000.

[0234] A 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 2.2 g of potassium carbonate (Aldrich reagent, 16 mmol) and 10.0 g of a terminal hydroxy compound of nonionic oligomer a11. After replacing the atmosphere in the apparatus with nitrogen, 100 mL of NMP and 30 mL of toluene were added, and the mixture was dehydrated at 100 ° C., heated to remove toluene, and 2.2 g of hexafluorobenzene (Aldrich reagent, 12 mmol) was added and reacted at 105 ° C. for 12 hours. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol, and nonionic oligomer a11 (terminal: fluoro group) represented by general formula (G4) was obtained. The number average molecular weight of this nonionic oligomer a11 was 6,000.

[0235] <Synthesis of Block Copolymer b7> The block copolymer b7 contains the above oligomer a8 as an ionic segment and the above oligomer a11 as a nonionic segment.

[0236] Block copolymer b7 was obtained in the same manner as block copolymer b6, except that nonionic oligomer a11 (6.81 g) was used instead of nonionic oligomer a9 (10.89 g). This block copolymer b7 had a number-average molecular weight of 130,000 and a weight-average molecular weight of 400,000.

[0237] The saturated crystallinity of block copolymer b7 was 0.8%, the glass transition temperature was 157°C, and the IEC was 2.4 meq / g. The electrolyte membrane prepared using block copolymer b7 was confirmed to have a bicontinuous-like phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed a continuous phase), but some discontinuous structures were observed.

[0238] Comparative Example 3 Synthesis of nonionic oligomer a13 represented by general formula (G8) A nonionic oligomer a13 having a terminal hydroxy group was obtained in the same manner as in the synthesis of the nonionic oligomer a1 having a terminal hydroxy group, except that 23.65 g of 4,4'-difluorodiphenyl sulfone was used instead of 4,4'-difluorobenzophenone. The number average molecular weight of the terminal hydroxy group of this nonionic oligomer a13 was 10,000.

[0239] A nonionic oligomer a13 (terminal fluoro group) represented by general formula (G8) was obtained in the same manner as in the synthesis of nonionic oligomer a1, except that 10.0 g of the terminal hydroxy group of nonionic oligomer a13 was used instead of 20.0 g of the terminal hydroxy group of nonionic oligomer a1. The number average molecular weight of this nonionic oligomer a13 was 11,000. In general formula (G8), m represents an integer of 1 or greater.

[0240]

[0241] <Synthesis of Ionic Oligomer a12 Represented by General Formula (G9)> Ionic oligomer a12 (terminal: OM group) represented by general formula (G9) was obtained in the same manner as in the synthesis of ionic oligomer a2, except that 44.94 g (98.1 mmol) of 3,3'-disulfonic acid sodium salt-4,4'-difluorodiphenyl sulfone obtained in Synthesis Example 3 was used instead of 41.60 g of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone. The number average molecular weight of this ionic oligomer a12 was 41,000. In general formula (G9), M represents a hydrogen atom, Na, or K, and n represents an integer of 1 or greater.

[0242]

[0243] <Synthesis of Block Copolymer b8> The block copolymer b8 contains the above oligomer a12 as an ionic segment and the above oligomer a13 as a nonionic segment.

[0244] A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with ionic oligomer a12 (45.76 g) and nonionic oligomer a13 (8.93 g), and NMP was added so that the total amount of oligomer charged was 7 wt%, and the reaction was carried out at 105 ° C. for 24 hours. Reprecipitation was carried out in a large amount of isopropyl alcohol / NMP mixed solution (weight ratio 2 / 1), and purification was carried out with a large amount of isopropyl alcohol to obtain block copolymer b8. The number average molecular weight of this block copolymer b8 was 120,000, and the weight average molecular weight was 290,000.

[0245] The saturated crystallinity of block copolymer b8 was 0.0%, the glass transition temperature was 231°C, and the IEC was 2.4 meq / g. An electrolyte membrane prepared using block copolymer b8 was confirmed to have a bicontinuous-like phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups both formed continuous phases).

[0246] [Measurement Results] Table 1 shows 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 the proton conductivity and the dry / wet dimensional change rate.

[0247]

[0248] In Examples 1 to 5, the electrolyte material (I) having a saturated crystallinity of 5% to 30% was used, and therefore the dry-wet dimensional change rate was small and the proton conductivity was high at low and high humidity. In other words, both mechanical durability and proton conductivity were achieved at a relatively high level.

[0249] On the other hand, in Comparative Examples 1 to 3, the saturated crystallinity is lower than 5%. As a result, the dry / wet dimensional change rate or proton conductivity is poor. In other words, mechanical durability and proton conductivity are not compatible.

[0250] [Examples 11 to 15] The electrolyte membranes (specimens) with a "crystallinity of 0%" prepared using the electrolyte materials of Examples 1 to 5 were hot-pressed under the conditions under which the crystallinity no longer changed in the above-mentioned "(4) Measurement of saturated crystallinity," and the dry / wet dimensional change rate and proton conductivity were measured. The results are shown in Table 2.

[0251]

[0252] As shown in Examples 1 to 5 in Table 1, the electrolyte membranes (specimens) prepared using the electrolyte material (I) of the present invention have relatively high levels of mechanical durability (dry and wet dimensional change rate) and proton conductivity even when crystallization has not progressed (even when the crystallinity is 0%). However, by advancing the crystallization, the mechanical durability (dry and wet dimensional change rate) and proton conductivity are further improved, as shown in Table 2.

[0253] [Electrolyte Material (II)] [Example 21] <Block Copolymer b21> The aforementioned block copolymer b1 was used as block copolymer b21. The block copolymer b21 exhibited a crystallization peak by DSC, and the heat of crystallization was 15.8 J / g. Therefore, the product of IEC and heat of crystallization was 39.5.

[0254] Example 22 Block Copolymer b22 The block copolymer b2 described above was used as block copolymer b22. A crystallization peak was observed by DSC for block copolymer b22, and the heat of crystallization was 13.2 J / g. Therefore, the product of IEC and heat of crystallization was 35.6.

[0255] Example 23 Synthesis of Ionic Oligomer a24 Represented by General Formula (G5) Ionic oligomer a24 was obtained in the same manner as in the synthesis of ionic oligomer a2, except that the amount of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone used was 41.38 g (98.0 mmol). The number average molecular weight of this ionic oligomer a24 was 35,000.

[0256] Synthesis of Ionic Oligomer a24' Represented by General Formula (G6) An NMP solution containing ionic oligomer a24' (terminal: OM group) represented by general formula (G6) was obtained in the same manner as in the synthesis of ionic oligomer a2', except that 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 %) used was 15.3 g. The number average molecular weight of this oligomer a24' was 70,000.

[0257] <Synthesis of Block Copolymer b23> The block copolymer b23 contains the above oligomer a24' as an ionic segment and the above oligomer a1 as a nonionic segment.

[0258] Block copolymer b23 was obtained in the same manner as for block copolymer b1, except that ionic oligomer a24' (37.16 g) was used instead of ionic oligomer a2' (49.0 g) and the amount of nonionic oligomer a1 was 5.80 g in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. The number-average molecular weight of this block copolymer b23 was 190,000 and the weight-average molecular weight was 440,000.

[0259] The IEC of the block copolymer b23 was 2.4 meq / g. The electrolyte membrane prepared using the block copolymer b23 exhibited a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups formed a continuous phase). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 16.6 J / g. Therefore, the product of the IEC and the heat of crystallization was 39.8.

[0260] Example 24 Synthesis of Nonionic Oligomer a21 Represented by General Formula (G10) 1.1 g of potassium carbonate (Aldrich reagent, 8 mmol) and 20.0 g (1 mmol) of the terminal hydroxy compound of nonionic oligomer a1 were placed in a 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere inside the flask with nitrogen, 100 mL of NMP and 30 mL of toluene were added, and the mixture was dehydrated at 100°C and then heated to remove the toluene. 0.84 g of 2,6-difluorobenzonitrile (Aldrich reagent, 6 mmol) was then added, and the mixture was reacted at 105°C for 12 hours. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol, yielding nonionic oligomer a21 (terminal: fluoro group) represented by the following general formula (G10). The number average molecular weight of this nonionic oligomer a21 was 21,000. In general formula (G10), m represents an integer of 1 or more.

[0261]

[0262] <Synthesis of Ionic Oligomer a24" Represented by General Formula (G11) Below> 0.56 g of potassium carbonate (Aldrich reagent, 400 mmol) and 37.16 g of ionic oligomer a24 were placed in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere inside the reactor with nitrogen, 400 mL of NMP was added and the contents were dissolved at 60°C, followed by the addition of 11.4 g of a 2,6-difluorobenzonitrile / NMP solution (1 wt %). The reaction was carried out at 80°C for 18 hours, yielding 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" was 70,000. In general formula (G11), M represents a hydrogen atom, Na, or K, and n represents an integer of 1 or greater.

[0263]

[0264] <Synthesis of Block Copolymer b24> The block copolymer b24 contains the above oligomer a24'' as an ionic segment and the above oligomer a21 as a nonionic segment.

[0265] Block copolymer b24 was obtained in the same manner as in the synthesis of block copolymer b1, except that 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. This block copolymer b24 had a number average molecular weight of 100,000 and a weight average molecular weight of 260,000.

[0266] The IEC of the block copolymer b24 was 2.2 meq / g. The electrolyte membrane prepared using the block copolymer b24 exhibited a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups co-formed a continuous phase). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 20.1 J / g. Therefore, the product of the IEC and the heat of crystallization was 44.2.

[0267] Example 25 Synthesis of Block Copolymer b25 Block copolymer b25 contains the above oligomer a24'' as an ionic segment and the above oligomer a1 as a nonionic segment.

[0268] Block copolymer b25 was obtained in the same manner as block copolymer b24, except that nonionic oligomer a1 (9.29 g) was used instead of nonionic oligomer a21 (5.80 g). The number-average molecular weight of block copolymer b25 was 150,000, and the weight-average molecular weight was 380,000.

[0269] The IEC of the block copolymer b25 was 2.1 meq / g. The electrolyte membrane prepared using the block copolymer b25 exhibited a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups co-formed a continuous phase). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 22.0 J / g. Therefore, the product of the IEC and the heat of crystallization was 46.2.

[0270] Example 26 Block Copolymer b26 The block copolymer b5 was used as block copolymer b26. A crystallization peak was observed by DSC for block copolymer b26, and the heat of crystallization was 21.1 J / g. Therefore, the product of IEC and heat of crystallization was 44.3.

[0271] Example 27 Synthesis of Block Copolymer b27 Block copolymer b27 contains the above oligomer a2' as an ionic segment and the above oligomer a1 as a nonionic segment.

[0272] Block copolymer b27 was obtained in the same manner as in Example 1, except that the amount of nonionic oligomer a1 used was 4.1 g. The number average molecular weight of this block copolymer b27 was 160,000 and the weight average molecular weight was 410,000.

[0273] The IEC of the block copolymer b27 was 2.9 meq / g. The electrolyte membrane prepared using the block copolymer b27 exhibited a bicontinuous phase-separated structure (a continuous phase consisting of hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 12.1 J / g. Therefore, the product of the IEC and the heat of crystallization was 35.1.

[0274] Comparative Example 21 Synthesis of Nonionic Oligomer a31 Represented by General Formula (G12) 16.59 g of potassium carbonate (Aldrich reagent, 120 mmol), 25.8 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, and 20.3 g of 4,4'-difluorobenzophenone (Aldrich reagent, 93 mmol) were placed in a 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere in the reactor with nitrogen, 300 mL of NMP and 100 mL of toluene were added. After dehydration at 160°C, the mixture was heated to remove toluene, and polymerization was carried out at 180°C for 1 hour. Purification by reprecipitation into a large amount of methanol yielded nonionic oligomer a31 with a terminal hydroxy group. The number average molecular weight of the terminal hydroxy group of this nonionic oligomer a31 was 10,000.

[0275] A 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 1.1 g of potassium carbonate (Aldrich reagent, 8 mmol) and 20.0 g (2 mmol) of a terminal hydroxy form of nonionic oligomer a31. After replacing the atmosphere inside the apparatus with nitrogen, 100 mL of NMP and 30 mL of cyclohexane were added, and the mixture was dehydrated at 100°C. After the temperature was raised to remove the cyclohexane, 4.0 g of decafluorobiphenyl (Aldrich reagent, 12 mmol) was added and reacted at 105°C for 1 hour. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol to obtain nonionic oligomer a31 (terminal: fluoro group) represented by the following general formula (G12). The number average molecular weight of this nonionic oligomer a31 was 11,000. In general formula (G12), m represents an integer of 1 or greater.

[0276]

[0277] <Synthesis of Ionic Oligomer a32 Represented by General Formula (G5)> A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 27.6 g of potassium carbonate (Aldrich reagent, 200 mmol), 12.9 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.3 g of 4,4'-biphenol (Aldrich reagent, 50 mmol), 39.3 g (93 mmol) of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 17.9 g of 18-crown-6 ether (Wako Pure Chemical Industries, 82 mmol). After replacing the atmosphere in the reactor with nitrogen, 300 mL of NMP and 100 mL of toluene were added, and the mixture was dehydrated at 170°C, heated to remove toluene, and polymerization was carried out at 180°C for 1 hour. The resulting ionic oligomer a22 (terminal: OM group) represented by the general formula (G5) was purified by reprecipitation with a large amount of isopropyl alcohol. The number average molecular weight of this ionic oligomer a22 was 16,000.

[0278] <Synthesis of Block Copolymer b31> The block copolymer b31 contains the above oligomer a32 as an ionic segment and the above oligomer a31 as a nonionic segment.

[0279] A 500 mL three-neck flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark trap was charged with 0.56 g of potassium carbonate (Aldrich reagent, 4 mmol) and 16 g (1 mmol) of ionic oligomer a32. After replacing the atmosphere inside the apparatus with nitrogen, 100 mL of NMP and 30 mL of cyclohexane were added, and the mixture was dehydrated at 100 °C. The temperature was then raised to remove the cyclohexane. 11 g (1 mmol) of nonionic oligomer a31 was added, and the reaction was carried out at 105 °C for 24 hours. Block copolymer b31 was obtained by reprecipitation purification in a large amount of isopropyl alcohol. The number average molecular weight of this block copolymer b31 was 150,000, and the weight average molecular weight was 3,400,000,000.

[0280] The IEC of the block copolymer b31 was 1.7 meq / g. The electrolyte membrane prepared using the block copolymer b31 exhibited a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups co-formed a continuous phase). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 22.5 J / g. Therefore, the product of the IEC and the heat of crystallization was 38.3.

[0281] Comparative Example 22 Synthesis of Nonionic Group Oligomer a33 Represented by General Formula (G13) A terminal hydroxyl form of nonionic oligomer a33 was synthesized in the same manner as in Comparative Example 21, except that 18.62 g of 4,4'-biphenol (Aldrich reagent, 100 mmol) was used instead of 25.8 g (100 mmol) of K-DHBP in the synthesis of nonionic oligomer 31 in Comparative Example 21, and the amount of 4,4'-difluorobenzophenone charged was changed to 21.41 g. The number average molecular weight was 22,000.

[0282] In addition, nonionic oligomer a33 (terminal: fluoro group) was synthesized in the same manner as in Comparative Example 21, except that 50.0 g (2 mmol) of the terminal hydroxy compound of nonionic oligomer a33 was charged instead of the terminal hydroxy compound of nonionic oligomer a31. The number average molecular weight was 23,000. In general formula (G13), m represents an integer of 1 or greater.

[0283]

[0284] <Synthesis of Ionic Group Oligomer a34 Represented by General Formula (G5)> A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap 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'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 17.9 g of 18-crown-6 ether (Wako Pure Chemical Industries, Ltd., 82 mmol). After replacing the atmosphere in the reactor with nitrogen, 300 mL of NMP and 100 mL of toluene were added, and the mixture was dehydrated at 170°C, heated to remove toluene, and polymerization was carried out at 180°C for 1 hour. The resulting ionic oligomer a34 (terminal: OM group) represented by the general formula (G5) was purified by reprecipitation with a large amount of isopropyl alcohol, and the number average molecular weight of the ionic oligomer a34 was 28,000.

[0285] <Synthesis of Block Copolymer b32> The block copolymer b32 contains the above oligomer a34 as an ionic segment and the above oligomer a33 as a nonionic segment.

[0286] Block copolymer b32 was obtained in the same manner as in Comparative Example 21, except that 26 g (1 mmol) of ionic oligomer a34 was used instead of ionic oligomer a32 and 21 g (1 mmol) of nonionic oligomer a33 was used instead of nonionic oligomer a31. The number average molecular weight of this block copolymer b32 was 110,000 and the weight average molecular weight was 380,000.

[0287] The IEC of the block copolymer b32 was 1.9 meq / g. The electrolyte membrane prepared using the block copolymer b32 exhibited a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups co-formed a continuous phase). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 25.3 J / g. Therefore, the product of the IEC and the heat of crystallization was 48.1.

[0288] Comparative Example 23 Synthesis of Ionic Group Oligomer a36 Represented by General Formula (G5) Ionic oligomer a36 (terminal: OM group) was obtained in the same manner as in Comparative Example 21, except that the amount of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone charged was changed to 40.1 g (95 mmol). The number average molecular weight of this ionic oligomer a36 was 21,000.

[0289] <Synthesis of Block Copolymer b33> Block copolymer b33 contains the above oligomer a36 as an ionic segment and the above oligomer a31 as a nonionic segment.

[0290] Block copolymer b33 was obtained in the same manner as in Comparative Example 21, except that 21 g (1 mmol) of ionic oligomer a36 was used instead of ionic oligomer a32. The number average molecular weight of this block copolymer b33 was 140,000 and the weight average molecular weight was 350,000.

[0291] The IEC of the block copolymer b33 was 2.1 meq / g. The electrolyte membrane prepared using the block copolymer b33 exhibited a bicontinuous phase-separated structure (hydrophilic domains containing ionic groups and hydrophobic domains not containing ionic groups co-formed a continuous phase). Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 16.0 J / g. Therefore, the product of the IEC and the heat of crystallization was 33.6.

[0292] Comparative Example 24 Synthesis of Nonionic Oligomer a35 Represented by General Formula (G14) A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 16.59 g of potassium carbonate (Aldrich reagent, 120 mmol), 25.8 g (100 mmol) of K-DHBP obtained in Synthesis Example 1, and 20.3 g of 4,4'-difluorobenzophenone (Aldrich reagent, 93 mmol). After purging the reactor with nitrogen, 300 mL of NMP and 100 mL of toluene were added. After dehydration at 160°C, the mixture was heated to remove toluene, and polymerization was carried out at 180°C for 1 hour. Purification was carried out by reprecipitation with a large amount of methanol to obtain a terminal hydroxyl form of nonionic oligomer a35. The number average molecular weight of the terminal hydroxyl group of this nonionic oligomer a35 was 10,000.

[0293] A 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 1.1 g of potassium carbonate (Aldrich reagent, 8 mmol) and 20.0 g (2 mmol) of the terminal hydroxy form of nonionic group oligomer a35. After purging the atmosphere inside the flask with nitrogen, 100 mL of NMP and 30 mL of cyclohexane were added, and the mixture was dehydrated at 100°C. The temperature was then raised to remove the cyclohexane, and 3.0 g of bis(4-fluorophenylsulfone) (Aldrich reagent, 12 mmol) was added, followed by a reaction at 105°C for 1 hour. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol, yielding nonionic oligomer a35 (terminal fluoro group) represented by the following general formula (G14). The number average molecular weight of this nonionic oligomer a35 was 11,000. In general formula (G14), m represents an integer of 1 or greater.

[0294]

[0295] <Synthesis of Ionic Group Oligomer a38 Represented by General Formula (G5)> A 2,000 mL SUS polymerization reactor equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap was charged with 27.6 g of potassium carbonate (Aldrich reagent, 200 mmol), 12.9 g (50 mmol) of K-DHBP obtained in Synthesis Example 1, 9.3 g of 4,4'-biphenol (Aldrich reagent, 50 mmol), 40.1 g (95 mmol) of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2, and 17.9 g of 18-crown-6 (82 mmol, Wako Pure Chemical Industries, Ltd.). After replacing the atmosphere in the reactor with nitrogen, 300 mL of NMP and 100 mL of toluene were added, and the mixture was dehydrated at 1170°C, heated to remove toluene, and then polymerized at 180°C for 1 hour. The resulting product was purified by reprecipitation with a large amount of isopropyl alcohol to obtain an ionic oligomer a38 (terminal: OM group) represented by the general formula (G5). The number average molecular weight of this ionic oligomer a38 was 21,000.

[0296] <Synthesis of Block Copolymer b34> Block copolymer b34 contains the above oligomer a38 as an ionic segment and the above oligomer a35 as a nonionic segment.

[0297] A 500 mL three-neck flask equipped with a stirrer, nitrogen inlet tube, and Dean-Stark trap was charged with 0.56 g of potassium carbonate (Aldrich reagent, 4 mmol) and 21 g (1 mmol) of ionic oligomer a38. After replacing the atmosphere inside the apparatus with nitrogen, 100 mL of NMP and 30 mL of cyclohexane were added, and the mixture was dehydrated at 100 ° C., the temperature was raised to remove the cyclohexane, and 11 g (1 mmol) of nonionic oligomer a35 was added and reacted at 105 ° C. for 24 hours. Purification was carried out by reprecipitation with a large amount of isopropyl alcohol, yielding block copolymer b34. The number average molecular weight of this block copolymer b34 was 140,000 and the weight average molecular weight was 320,000.

[0298] The IEC of the block copolymer b34 was 2.2 meq / g. A lamellar phase-separated structure was confirmed in the electrolyte membrane prepared using the block copolymer b34. Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 12.5 J / g. Therefore, the product of the IEC and the heat of crystallization was 27.5.

[0299] Comparative Example 25 Synthesis of Nonionic Oligomer a37 Represented by General Formula (G15) 13.82 g of potassium carbonate (Aldrich reagent, 100 mmol), 20.66 g (80 mmol) of K-DHBP obtained in Synthesis Example 1, and 20.95 g of 4,4'-difluorobenzophenone (Aldrich reagent, 96 mmol) were placed in a 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After replacing the atmosphere in the flask with nitrogen, 90 mL of NMP and 45 mL of toluene were added, and the mixture was dehydrated at 180°C. The temperature was then raised to remove the toluene, and polymerization was carried out at 210°C for 1 hour. Purification was carried out by reprecipitation with a large amount of water, and washing with hot methanol yielded nonionic oligomer a37 represented by general formula (G15). The number average molecular weight of this nonionic oligomer a37 was 3,000. In general formula (G15), N ３ represents an integer of 1 or more.

[0300]

[0301] <Synthesis of Block Copolymer b35> 8.29 g of potassium carbonate (Aldrich reagent, 60 mmol), 8.94 g of 4,4'-biphenol (Aldrich reagent, 48 mmol), and 16.89 g (40 mmol) of disodium-3,3'-disulfonate-4,4'-difluorobenzophenone obtained in Synthesis Example 2 were placed in a 500 mL three-neck flask equipped with a stirrer, a nitrogen inlet tube, and a Dean-Stark trap. After the atmosphere inside the flask was replaced with nitrogen, 90 mL of NMP and 45 mL of toluene were added, and the mixture was dehydrated at 180°C. After the temperature was increased to remove the toluene, polymerization was carried out at 210°C for 1 hour to obtain ionic oligomer a40. The number average molecular weight of this ionic oligomer a40 was 4,000.

[0302] Next, 17.46 g (40 mmol) of nonionic oligomer a37 and 20 mL of toluene were added, and the mixture was dehydrated again at 180° C., and then the temperature was increased to remove toluene, followed by polymerization for 8 hours at 230° C. to obtain block copolymer b35. This block copolymer b35 had a number average molecular weight of 110,000 and a weight average molecular weight of 271,000.

[0303] The IEC of the block copolymer b35 was 2.1 meq / g. An island-like phase-separated structure was confirmed in the electrolyte membrane prepared using the block copolymer b35. Furthermore, a crystallization peak was observed by DSC, and the heat of crystallization was 11.1 J / g. Therefore, the product of the IEC and the heat of crystallization was 23.3.

[0304] Comparative Example 26 Block Copolymer b36 The block copolymer b8 described above was used as block copolymer b36. Block copolymer b36 did not show a crystallization peak by DSC. Therefore, the product of IEC and heat of crystallization could not be calculated.

[0305] [Measurement Results] Table 3 shows the measurement results of the electrolyte materials obtained in Examples 21 to 27 and Comparative Examples 21 to 26.

[0306]

[0307] In Examples 21 to 27, an electrolyte material (II) was used in which the IEC was 1.8 meq / g or more and 3.0 meq / g or less and the product of the IEC and the heat of crystallization (J / g) was 35.0 or more and 47.0 or less, and therefore the dry / wet dimensional change rate was small and the proton conductivity was high at low and high humidity. In other words, both mechanical durability and proton conductivity were achieved at a relatively high level.

[0308] On the other hand, in all of Comparative Examples 21 to 26, either the IEC or the product of the IEC and the heat of crystallization (J / g) was outside the above range, and the dry / wet dimensional change rate or proton conductivity was poor. In other words, both mechanical durability and proton conductivity were not achieved.

[0309] In the present invention, from the viewpoint of achieving both mechanical durability and proton conductivity at a relatively high level, it is preferable that the wet / dry dimensional change rate is 7.0% or less, the proton conductivity at low humidification is 0.85 mS / cm or more, and the proton conductivity at high humidification is 9.00 mS / cm or more; it is more preferable that the wet / dry dimensional change rate is 6.5% or less, the proton conductivity at low humidification is 0.90 mS / cm or more, and the proton conductivity at high humidification is 9.50 mS / cm or more; it is even more preferable that the wet / dry dimensional change rate is 6.0% or less, the proton conductivity at low humidification is 1.00 mS / cm or more, and the proton conductivity at high humidification is 11.00 mS / cm or more; and it is particularly preferable that the wet / dry dimensional change rate is 5.7% or less, the proton conductivity at low humidification is 1.10 mS / cm or more, and the proton conductivity at high humidification is 13.00 mS / cm or more.

[0310] 1 phase 1 2 phase 2

Claims

1. A polymer electrolyte material made of a block copolymer having a segment containing an ionic group (hereinafter referred to as an "ionic segment") and a segment not containing an ionic group (hereinafter referred to as a "nonionic segment"), the polymer electrolyte material having a phase-separated structure, in which, when the number average molecular weight of the ionic segment is Mn1 and the number average molecular weight of the nonionic segment is Mn2, Mn2 is 15,000 or more, satisfies the following formula 1, and satisfies at least one of the following conditions 1 and 2: 1.7≦Mn1 / Mn2≦7.0 (Formula 1) <Condition 1> The saturated crystallinity of the polymer electrolyte material measured 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 measured by differential scanning calorimetry is 35.0 or more and 47.0 or less.

2. The polymer electrolyte material according to claim 1 , which has a bicontinuous or lamellar phase-separated structure.

3. 3. The polymer electrolyte material according to claim 1, wherein the phase-separated structure has an average periodic size of 15 to 100 nm.

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

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

6. 6. The polymer electrolyte material according to claim 1, wherein the block copolymer has a linker site that bonds between the ionic segment and the nonionic segment.

7. The polymer electrolyte material according to any one of claims 1 to 6, wherein the nonionic segment contains a structure represented by the following general formula (S3): 【Chemistry 1】 (In general formula (S3), Ar ５ ~Ar ８ each independently represents a substituted or unsubstituted arylene group. ５ ~Ar ８ None of Y has an ionic group. ３ and Y ４ each independently represents a ketone group or a protecting group that can be derived to a ketone group. * represents a bond to general formula (S3) or another structural unit.

8. The polymer electrolyte material according to claim 7 , wherein the structure represented by the general formula (S3) is a structure represented by the following general formula (S4): 【Chemistry 2】 (In general formula (S4), Y ３ and Y ４ each independently represents a ketone group or a protecting group that can be derived to a ketone group. * represents a bond to general formula (S4) or another structural unit.

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

10. A catalyst layer-attached electrolyte membrane formed using the polymer electrolyte molded product according to claim 9.

11. A membrane electrode assembly formed using the polymer electrolyte molded product according to claim 9.

12. A solid polymer fuel cell constructed using the polymer electrolyte molded product according to claim 9.

13. A water electrolysis hydrogen generating device comprising the polymer electrolyte molded product according to claim 9.

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