Abstract: To provide an electrolyte material for polymer electrolyte fuel cells having a high softening temperature and being excellent in durability, and an electrolyte membrane and a process for producing a membrane-electrode assembly using it. An electrolyte material made of a polymer containing a segment A of a polymer containing repeating units based on a perfluoromonomer having an ion exchange group and having a polymerizable double bond, at least one of carbon atoms in the polymerizable double bond being a carbon atom contained in an alicyclic structure, and a segment B of a fluoropolymer containing substantially no ion exchange group, and an electrolyte membrane and a membrane-electrode assembly using it.

Abstract: To provide a fuel cell system provided with a polymer electrolyte fuel cell which is excellent in the power generation characteristics under high temperature and low or no humidity conditions. A fuel cell system 20 comprising a polymer electrolyte fuel cell 22 having a membrane/electrode assembly 10 having a catalyst layer containing a polymer (H) which has repeating units based on a perfluoromonomer having an alicyclic structure and has ion exchange groups, a temperature controlling means for controlling temperature of the polymer electrolyte fuel cell 22, a temperature sensor 38 for detecting temperature of the polymer electrolyte fuel cell 22, and a controlling device 40 for controlling the temperature controlling means based on temperature information from the temperature sensor 38 so that the maximum temperature of the polymer electrolyte fuel cell 22 becomes within the range of from 90 to 140° C.

Abstract: It is to provide a membrane/electrode assembly excellent in the power generation characteristics under low or no humidity conditions and under high humidity conditions; and an electrolyte material having a low water content, suitable for a catalyst layer of a membrane/electrode assembly. It is to use an electrolyte material, which comprises a polymer (H) having ion exchange groups converted from precursor groups in a polymer (F), the polymer (F) having repeating units (A) based on a perfluoromonomer having a precursor group of an ion exchange group and a 5-membered ring to which the precursor group is bonded and repeating units (B) represented by the formula (u2), and having an intrinsic viscosity of at least 2.3 dL/g. wherein R1 to R4 are a fluorine atom, a C1-6 perfluoroalkyl group or the like.

Abstract: It is to provide a membrane/electrode assembly excellent in the power generation characteristics under low or no humidity conditions and under high humidity conditions, and an electrolyte material suitable for a catalyst layer of the membrane/electrode assembly. It is to use an electrolyte material, which comprises a polymer (H) having ion exchange groups converted from precursor groups in a polymer (F) having repeating units (A) having a precursor group represented by the formula (g1) and repeating units (B) based on a perfluoromonomer having a 5-membered ring, and having a density of at most 2.03 g/cm3, the polymer (H) having an ion exchange capacity of from 1.3 to 2.3 meq/g dry resin: wherein Q1 and Q2 are a perfluoroalkylene group having an etheric oxygen atom, or the like, and Y is F or the like.

Abstract: To improve the utilization efficiency of a noble metal catalyst in a catalyst layer of an electrode for a polymer electrolyte fuel cell. A precursor material obtained by polymerizing a perfluoromonomer having a fluorosulfonyl group in the presence of noble metal catalyst fine particles supported carbon particles, a material for a catalyst layer obtained by converting the fluorosulfonyl groups of the precursor material to sulfonic acid groups, and a membrane/electrode assembly for a polymer electrolyte fuel cell having a catalyst layer using the material for a catalyst layer.

Abstract: It is to provide an electrolyte material with which an increase in the water content can be suppressed even when the ion exchange capacity of a polymer having repeating units based on a monomer having a dioxolane ring is high; and a membrane/electrode assembly excellent in the power generation characteristics under low or no humidity conditions and under high humidity conditions. It is to use an electrolyte material, which comprises a polymer (H) having ion exchange groups converted from precursor groups in a polymer (F), and having an ion exchange capacity of at least 1.35 meq/g dry resin, the polymer (F) having repeating units (A) based on a perfluoromonomer having a precursor group of an ion exchange group and a dioxolane ring and repeating units (B) based on a perfluoromonomer having no precursor group and having a dioxolane ring, and having a TQ of at least 200° C.

Abstract: To provide an electrolyte polymer for fuel cells, an electrolyte membrane, a membrane/electrode assembly for fuel cells excellent in the durability. An electrolyte polymer for fuel cells made of a perfluorocarbon polymer having ion exchange groups (which may contain etheric oxygen atoms), characterized in that the value calculated by dividing an absorption area SCH derived mainly from a C—H bond in the range of from 3,100 cm?1 to 2,800 cm?1 by an absorption area SCF derived mainly from a C—F bond in the range of from 2,700 cm?1 to 2,000 cm?1, as measured by means of infrared spectrophotometry, is less than 0.005, an electrolyte membrane and a membrane/electrode assembly.

Abstract: To provide a membrane/electrode assembly for polymer electrolyte fuel cells, a polymer electrolyte fuel cell and processes for their production, which make it possible to stably exhibit a high power generation performance in various environments. A membrane/electrode assembly for polymer electrolyte fuel cells, which comprises a first electrode having a first catalyst layer and a first gas diffusion layer, a second electrode having a second catalyst layer and a second gas diffusion layer, and a polymer electrolyte membrane disposed between the first electrode and the second electrode, wherein the 90° peel strength at least one of the interface between the first electrode and the polymer electrolyte membrane and the interface between the second electrode and the polymer electrolyte membrane is at least 0.03 N/cm.

Abstract: An electrolyte material for polymer electrolyte fuel cells, which is made of a polymer containing repeating units based on a fluoromonomer having a radical polymerization reactivity, wherein the repeating units contain a 5-membered ring (which may contain 1 or 2 oxygen atoms), of which at least one carbon atom is contained in the main chain of the polymer, and an ionic group such as a sulfonic acid group which is bonded to the 5-membered ring directly or via a perfluoroalkylene group having a linear or branched structure; and the polymer has a softening temperature of at least 120° C.

Abstract: An electrolyte membrane characterized by comprising a porous body formed from a melt-moldable fluororesin and having interconnected pores and an ion exchange resin with which the interconnected pores are filled, is provided. Specifically, the porous body is formed, for example, from an ethylene/tetrafluoroethylene copolymer, a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/[CF2?CF—(OCF2CFY)a—Oc—(CF2)b—SO3H] copolymer (wherein Y is a fluorine atom or a trifluoromethyl group, a is an integer of 0 to 3, b is an integer of from 0 to 12, and c is 0 or 1, provided that when b=0, C=0), or the like. An electrolyte membrane reinforced by such a porous body has high mechanical strength even if it is thin, and is excellent in dimensional stability when hydrated, and a polymer electrolyte fuel cell with a membrane-electrode assembly having the electrolyte membrane provides a high output and is excellent in durability.

Abstract: To provide a polymer electrolyte membrane for polymer electrolyte fuel cells having high mechanical strength and excellent dimensional stability when it contains water even when it is made thin and the concentration of ionic groups is increased so as to reduce the electrical resistance, and a membrane/electrode assembly providing high output and having excellent durability. A polymer electrolyte membrane 15, which comprises a fluorinated proton conductive polymer (i) having a proton conductivity of at least 0.06 S/cm in an atmosphere at a temperature of 80° C. under a relative humidity of 50%, and (ii) having repeating units based on a vinyl ether type monomer with a mass (equivalent weight) of at most 400 per 1 mol of ionic groups and repeating units based on a perfluoromonomer (except for the above vinyl ether type monomer) and a fluorinated reinforcing material; and a membrane/electrode assembly 10 comprising the polymer electrolyte membrane 15 interposed between an anode 13 and a cathode 14.

Abstract: To provide a membrane/electrode assembly for polymer electrolyte fuel cells, a polymer electrolyte fuel cell and processes for their production, which make it possible to stably exhibit a high power generation performance in various environments. A membrane/electrode assembly for polymer electrolyte fuel cells, which comprises a first electrode having a first catalyst layer and a first gas diffusion layer, a second electrode having a second catalyst layer and a second gas diffusion layer, and a polymer electrolyte membrane disposed between the first electrode and the second electrode, wherein the 90° peel strength at least one of the interface between the first electrode and the polymer electrolyte membrane and the interface between the second electrode and the polymer electrolyte membrane is at least 0.03 N/cm.

Abstract: A thickened ion exchange polymer dispersion is obtained by applying ultrasonic vibration or a shearing force to an ion exchange polymer dispersion having a fluorinated polymer having sulfonic acid groups as an ion exchange polymer uniformly dispersed in a dispersion medium so that the viscosity of the dispersion at 25° C. at a shear rate of 10 (1/s) increases 2-2000 times in a thickening step. When formed into a membrane, the dispersion can forms an ion exchange membrane having a uniform and small thickness, high strength, which is free from cracking and shows constant swelling in water and steam. Further, a layer formed by applying a coating solution containing this dispersion and a catalyst powder comprising catalyst metal particles and a carbon support loaded with the catalyst metal particles to a substrate can be used to prepare a membrane-electrode assembly as a catalyst layer for at least one of the cathode and the anode by providing the catalyst layer adjacently to an ion exchange membrane.

Abstract: An electrolyte membrane for a polymer electrolyte fuel cell, which comprises an ion exchange membrane made of a fluoropolymer having a softening temperature of at least 90° C. and having acidic groups, and contains cerium atoms.

Abstract: A polymer electrolyte membrane made of a polymer has a low electrical resistance, high heat resistance and is strong against repeats of swelling and shrinkage. Thus, a membrane/electrode assembly for polymer electrolyte fuel cells having high power generation performance and excellent in durability can be provided. For a polymer electrolyte membrane 15 or for a catalyst layer 11 constituting electrodes 13 and 14, a polymer comprising units (U1) and units (U2) is used: Q1, Q2, Q3: a perfluoroalkylene group which may have —O— or the like; Rf1, Rf2: a perfluoroalkyl group which may have —O—; X1, X2: an oxygen atom or the like; a, b: 0 or the like; Y1, Y2: a fluorine atom or a monovalent perfluoroorganic group; and s, t: 0 to 1.

Abstract: A polymer electrolyte membrane made of a polymer has a low electrical resistance, high heat resistance and is strong against repeats of swelling and shrinkage. Thus, a membrane/electrode assembly for polymer electrolyte fuel cells having high power generation performance and excellent in durability can be provided. For a polymer electrolyte membrane 15 or for a catalyst layer 11 constituting electrodes 13 and 14, a polymer comprising units (U1) and units (U2) is used: Q1, Q2: a perfluoroalkylene group which may have —O— or the like; Rf1, Rf2: a perfluoroalkyl group which may have —O—; X: an oxygen atom or the like; a: 0 or the like; Y, Z: a fluorine atom, or a monovalent perfluoroorganic group such as —CF3; S: 0 to 1; and t: 0 to 3.

Abstract: To provide a polymer electrolyte material for polymer electrolyte fuel cells, which is an electrolyte material having a high ion exchange capacity and a low resistance, and which has a higher softening temperature than a conventional electrolyte material.

Abstract: The present invention provides a polymer membrane mainly made of an ion exchange resin which further comprises melt-spun fluororesin fibers such as fibers made of an ethylene-tetrafluoroethylene copolymer, a polyvinylidene fluoride or the like, having fiber diameters of from 0.01 to 20 ?m, fiber lengths of from 1 ?m to 10 mm and aspect ratios of at least 5 in an amount of from 1 to 40% based on the total mass. The polymer membrane is excellent in handleability and shows excellent dimensional stability when hydrated, and therefore a polymer electrolyte fuel cell provided with a membrane-electrode assembly having the polymer membrane as an electrolyte membrane has great durability.

Abstract: To provide an electrolyte material for polymer electrolyte fuel cells having a high softening temperature and being excellent in durability, and an electrolyte membrane and a process for producing a membrane-electrode assembly using it. An electrolyte material made of a polymer containing a segment A of a polymer containing repeating units based on a perfluoromonomer having an ion exchange group and having a polymerizable double bond, at least one of carbon atoms in the polymerizable double bond being a carbon atom contained in an alicyclic structure, and a segment B of a fluoropolymer containing substantially no ion exchange group, and an electrolyte membrane and a membrane-electrode assembly using it.

Abstract: To provide an electrolyte polymer for fuel cells, an electrolyte membrane, a membrane/electrode assembly for fuel cells excellent in the durability. An electrolyte polymer for fuel cells made of a perfluorocarbon polymer having ion exchange groups (which may contain etheric oxygen atoms), characterized in that the value calculated by dividing an absorption area SCH derived mainly from a C—H bond in the range of from 3,100 cm?1 to 2,800 cm?1 by an absorption area SCF derived mainly from a C—F bond in the range of from 2,700 cm?1 to 2,000 cm?1, as measured by means of infrared spectrophotometry, is less than 0.005, an electrolyte membrane and a membrane/electrode assembly.