Abstract: A membrane-electrode assembly for polymer electrolyte fuel cells which is excellent in water repellency and gas diffusivity and which exhibits a high output power density, can be obtained by using, as an electrolyte material for polymer electrolyte fuel cells, a fluoropolymer obtained by contacting a fluoropolymer which is excellent in gas diffusivity and which has alicyclic structures in its main chain and further has sulfonic acid groups, with fluorine gas for fluorination to increase water repellency and stabilize the molecule ends.

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: 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: A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1): CF2?CF(Rf)jSO2X ??(1) wherein j is 0 or 1, X is a fluorine atom, a chlorine atom or OM {wherein M is a hydrogen atom, an alkali metal atom or a group of NR1R2R3R4 (wherein each of R1, R2, R3 and R4 which may be the same or different, is a hydrogen atom or a monovalent organic group)}, and Rf is a C1-20 polyfluoroalkylene group having a straight chain or branched structure which may contain ether oxygen atoms.

Abstract: A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1): CF2?CF(Rf)jSO2X??(1) wherein j is 0 or 1, X is a fluorine atom, a chlorine atom or OM {wherein M is a hydrogen atom, an alkali metal atom or a group of NR1R2R3R4 (wherein each of R1, R2, R3 and R4 which may be the same or different, is a hydrogen atom or a monovalent organic group)}, and Rf is a C1-20 polyfluoroalkylene group having a straight chain or branched structure which may contain ether oxygen atoms.

Abstract: To provide an electrolyte polymer for polymer electrolyte fuel cells, made of a perfluorinated polymer having sulfonic groups, characterized in that in a test of immersing 0.1 g of the polymer in 50 g of a fenton reagent solution containing 3% of an aqueous hydrogen peroxide solution and 200 ppm of bivalent iron ions at 40° C. for 16 hours, the amount of eluted fluorine ions detected in the solution is not more than 0.002% of the total amount of fluorine in the polymer immersed. The electrolyte polymer of the present invention has very few unstable terminal groups and has an excellent durability, and therefore, is suitable as a polymer constituting an electrolyte membrane for polymer electrolyte fuel cells and a polymer contained in a catalyst layer.

Abstract: A fluorosulfonyl group-containing monomer having a high polymerization reactivity and plural fluorosulfonyl groups, a fluorosulfonyl group-containing polymer and a sulfonic acid group-containing polymer, obtained by using the monomer.

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 polymer electrolyte fuel cells, made of a perfluorinated polymer having sulfonic groups, characterized in that in a test of immersing 0.1 g of the polymer in 50 g of a fenton reagent solution containing 3% of an aqueous hydrogen peroxide solution and 200 ppm of bivalent iron ions at 40° C. for 16 hours, the amount of eluted fluorine ions detected in the solution is not more than 0.002% of the total amount of fluorine in the polymer immersed. The electrolyte polymer of the present invention has very few unstable terminal groups and has an excellent durability, and therefore, is suitable as a polymer constituting an electrolyte membrane for polymer electrolyte fuel cells and a polymer contained in a catalyst layer.

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: 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: Provided is a process for producing a fluoropolymer containing repeating units based on a fluoromonomer represented by the following formula (m) in an amount of from 5 to 50 mol % based on the entire repeating units in the polymer by polymerization reaction of tetrafluoroethylene and the fluoromonomer, wherein the polymerization reaction is carried out by continuously charging the reactor with tetrafluoroethylene and the fluoromonomer: wherein ml is an integer of from 1 to 6. Also provided is an electrolyte material for an electrolyte fuel cell which can be operated at a high temperature to obtain a high output, wherein the electrolyte material contains the fluoropolymer produced by the process.

Abstract: A fluorosulfonyl group-containing compound having a high polymerization reactivity, a process for its production, a sulfonyl group-containing polymerizable monomer led from the sulfonyl group-containing compound, and a polymer obtainable by polymerizing the sulfonyl group-containing polymerizable monomer, are provided. A compound (3) is fluorinated to form a compound (4), and then, the compound (4) is subjected to a decomposition reaction to produce a compound (5). A preferred compound (5-1) of the compound (5) is thermally decomposed to produce a compound (7-1) having a high polymerization reactivity. wherein RA is a bivalent organic group such as a fluoroalkylene group, RAF is a group having RA fluorinated, or the same group as RA, each of RB to RD which are independent of one another, is a hydrogen atom, etc., each of RBF to RDF is a fluorine atom, etc.

Abstract: A compound containing two fluorosulfonyl groups which are groups convertible to sulfonic acid groups, an intermediate therefor, and methods for their production with high productivity, are provided. Also provided are a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer. A method for producing a compound of the following formula (m0), such a compound, a fluorosulfonyl group-containing polymer obtained by polymerizing such a compound, and a sulfonic acid group-containing polymer obtained from such a polymer, provided that RF01 is a single bond or a C1-6 bivalent perfluoro organic group, RF02 is a C1-6 bivalent perfluoro organic group, and n is 0 or 1.

Abstract: An electrolyte material for a polymer electrolyte fuel cell, which is made of a copolymer comprising repeating units based on CF2?CFCF2OCF2CF2SO3H and repeating units based on tetrafluoroethylene and which has an ion exchange capacity of from 0.9 to 1.5 (meq/g dry resin). This electrolyte material has ion conductivity and durability equal to conventional electrolyte material, is easy to synthesize, has a softening point higher than electrolyte material heretofore widely used for application to fuel cells and is suitable for operation of a polymer electrolyte fuel cell at a temperature higher than the conventional material.

Abstract: A membrane-electrode assembly for polymer electrolyte fuel cells which is excellent in water repellency and gas diffusivity and which exhibits a high output power density, can be obtained by using, as an electrolyte material for polymer electrolyte fuel cells, a fluoropolymer obtained by contacting a fluoropolymer which is excellent in gas diffusivity and which has alicyclic structures in its main chain and further has sulfonic acid groups, with fluorine gas for fluorination to increase water repellency and stabilize the molecule ends.