Abstract: To provide a liquid composition capable of forming a membrane excellent in durability against hydrogen peroxide or peroxide radicals and excellent in hydrogen gas barrier property; a polymer electrolyte membrane; a membrane electrode assembly; and a polymer electrolyte fuel cell. Liquid composition comprising a liquid medium, an acid-type sulfonic acid group-containing fluorocarbon polymer of which the hydrogen gas permeation coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10% is at most 2.5×10?9 cm3·cm/(s·cm2·cmHg), and cerium atoms; a polymer electrolyte membrane 15 comprising the acid-type sulfonic acid group-containing fluorocarbon polymer, and cerium atoms; and a membrane electrode assembly 10 comprising an anode 13 having a catalyst layer, a cathode 14 having a catalyst layer, and the polymer electrolyte membrane 15 disposed between the anode 13 and the cathode 14.

Abstract: An acid-type sulfonic acid group-containing polymer containing perfluoromonomer units, no monomer units having a halogen atom other than a fluorine atom, and acid type sulfonic acid groups, whose hydrogen gas permeability coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10% is at most 2.5×10?9 cm3·cm/(s·cm2·cmHg), and whose mass reduction rate when immersed in hot water at 120° C. for 24 hours is at most 15 mass %. Liquid composition, membrane electrode assembly, polymer electrolyte fuel cell, and ion exchange membrane utilizing the acid-type sulfonic acid group-containing polymer.

Abstract: To provide a perfluoropolymer capable of producing an electrolyte membrane excellent in mechanical strength in high temperature environments; as well as a liquid composition, polymer electrolyte membrane, membrane electrode assembly and polymer electrolyte water electrolyzer, obtainable by using the perfluoropolymer. The perfluoropolymer of the present invention contains perfluoromonomer units, does not substantially contain units having a halogen atom other than a fluorine atom, does not substantially contain units having a ring structure, and has acid-type sulfonic acid groups, wherein the perfluoromonomer units contain at least one type of units A selected from the group consisting of perfluorovinyl ether units and perfluoroallyl ether units; the ion exchange capacity is from 0.9 to 1.4 milliequivalent/gram dry resin; and the storage modulus at 120° C. is at least 100 MPa.

Abstract: A fluorosulfonyl group-containing polymer having units represented by the following formula u1, a sulfonic acid group-containing polymer having fluorosulfonyl groups in the fluorosulfonyl group-containing polymer converted into sulfonic acid groups, its production method and its applications: wherein RF1 and RF2 are a C1-3 perfluoroalkylene group.

Abstract: A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used: wherein R1 and R2 are a C1-3 alkylene group, and RF1 and RF2 are a C1-3 perfluoroalkylene group.

Abstract: A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used: wherein R1 and R2 are a C1-3 alkylene group, and RF1 and RF2 are a C1-3 perfluoroalkylene group.

Abstract: To provide a polymer wherein a linking group that connects the main chain of the polymer and a cyclic perfluoroaliphatic disulfonimide skeleton, is a fluoroalkylene group which may have an ether oxygen atom. A polymer which has either one or both of units represented by formula u1-1 and units represented by formula u1-2: RF1, RF2: a C1-3 perfluoroalkylene group; RF3: a C1-6 perfluoroalkylene group; m: 0 or 1; and X: a hydrogen atom, an alkali metal atom, a fluorine atom, an alkyl group, ammonium or the like.

Abstract: To provide an acid-type sulfonic acid group-containing polymer which is excellent in hydrogen gas barrier properties and hot water resistance and which generates less oligomer during production; a liquid composition and a polymer electrolyte membrane comprising this acid-type sulfonic acid group-containing polymer; and a membrane electrode assembly and a polymer electrolyte fuel cell provided with the polymer electrolyte membrane. This acid-type sulfonic acid group-containing polymer is a polymer which has perfluoromonomer units, no monomer units having a halogen atom other than a fluorine atom, and acid-type sulfonic acid groups, and of which the hydrogen gas permeability coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10%, is at most 2.5×10?9 cm3·cm/(s·cm2·cmHg), and the mass reduction rate when being immersed in hot water at 120° C.

Abstract: To provide a perfluoropolymer capable of producing an electrolyte membrane excellent in electrical conductivity and mechanical strength under high temperature environment, as well as a liquid composition, a polymer electrolyte membrane, a membrane electrode assembly and a polymer electrolyte fuel cell, obtainable by using the perfluoropolymer. The perfluoropolymer of the present invention contains perfluoromonomer units, does not substantially contain units having a halogen atom other than a fluorine atom, does not substantially contain units having a ring structure, and has acid-type sulfonic acid groups, wherein the perfluoromonomer units contain at least one type of units A selected from the group consisting of perfluoro vinyl ether units and perfluoro allyl ether units; the ion exchange capacity is from 1.4 to 2.5 milliequivalent/gram dry resin; and the storage modulus at 120° C. is at least 60 MPa.

Abstract: To provide a liquid composition capable of forming a membrane excellent in durability against hydrogen peroxide or peroxide radicals and excellent in hydrogen gas barrier property; a polymer electrolyte membrane; a membrane electrode assembly; and a polymer electrolyte fuel cell. Liquid composition comprising a liquid medium, an acid-type sulfonic acid group-containing fluorocarbon polymer of which the hydrogen gas permeation coefficient under the conditions of a temperature of 80° C. and a relative humidity of 10% is at most 2.5×10?9 cm3·cm/(s·cm2·cmHg), and cerium atoms; a polymer electrolyte membrane 15 comprising the acid-type sulfonic acid group-containing fluorocarbon polymer, and cerium atoms; and a membrane electrode assembly 10 comprising an anode 13 having a catalyst layer, a cathode 14 having a catalyst layer, and the polymer electrolyte membrane 15 disposed between the anode 13 and the cathode 14.

Abstract: To provide a perfluoropolymer capable of producing an electrolyte membrane excellent in mechanical strength in high temperature environments; as well as a liquid composition, polymer electrolyte membrane, membrane electrode assembly and polymer electrolyte water electrolyzer, obtainable by using the perfluoropolymer. The perfluoropolymer of the present invention contains perfluoromonomer units, does not substantially contain units having a halogen atom other than a fluorine atom, does not substantially contain units having a ring structure, and has acid-type sulfonic acid groups, wherein the perfluoromonomer units contain at least one type of units A selected from the group consisting of perfluorovinyl ether units and perfluoroallyl ether units; the ion exchange capacity is from 0.9 to 1.4 milliequivalent/gram dry resin; and the storage modulus at 120° C. is at least 100 MPa.

Abstract: The present invention relates to a method for producing a 1,3-dioxolane compound represented by formula 1, the method containing step (a), in which hexafluoroacetone monohydrate is brought into contact with a metal fluoride, step (b), in which fluorine gas is brought into contact, and step (c), in which an olefin compound represented by formula 2 is brought into contact. In formulae 1 and 2, X1 to X4 each independently represent a hydrogen atom, fluorine atom, chlorine atom, or trifluoromethyl group.

Abstract: The present invention relates to a method for producing a 1,3-dioxolane compound represented by formula 1, the method containing step (a), in which hexafluoroacetone monohydrate is brought into contact with a metal fluoride, step (b), in which fluorine gas is brought into contact, and step (c), in which an olefin compound represented by formula 2 is brought into contact. In formulae 1 and 2, X1 to X4 each independently represent a hydrogen atom, fluorine atom, chlorine atom, or trifluoromethyl group.

Abstract: A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used: wherein R1 and R2 are a C1-3 alkylene group, and RF1 and RF2 are a C1-3 perfluoroalkylene group.

Abstract: A fluorosulfonyl group-containing polymer having units represented by the following formula u1, a sulfonic acid group-containing polymer having fluorosulfonyl groups in the fluorosulfonyl group-containing polymer converted into sulfonic acid groups, its production method and its applications: wherein RF1 and RF2 are a C1-3 perfluoroalkylene group.

Abstract: To provide a cathode active material with which a lithium ion secondary battery having favorable cycle characteristics and having a high energy density even when discharged at a high voltage can be obtained; a cathode comprising the cathode active material; and a lithium ion secondary battery having the cathode. A cathode active material comprising a composite oxide (A) containing Li and at least one transition metal element selected from the group consisting of Ni, Co and Mn, and the following particles (B) and the following fluorinated carbon material (C) present on the surface of the composite oxide (A): particles (B): particles containing an oxide of at least one metal element selected from the group consisting of Ti, Sn, Si, Al, Ce, Y, Zr, Co, W, V, Nb, Ta, La and Mg; and fluorinated carbon material (C): a fluorinated carbon material in the form of particles or fibers.

Abstract: To provide a cathode active material with which a lithium ion secondary battery having favorable cycle characteristics and having a high energy density even when discharged at a high voltage can be obtained; a cathode comprising the cathode active material; and a lithium ion secondary battery having the cathode. A cathode active material comprising a composite oxide (A) containing Li and at least one transition metal element selected from the group consisting of Ni, Co and Mn, and the following particles (B) and the following fluorinated carbon material (C) present on the surface of the composite oxide (A): particles (B): particles containing an oxide of at least one metal element selected from the group consisting of Ti, Sn, Si, Al, Ce, Y, Zr, Co, W, V, Nb, Ta, La and Mg; and fluorinated carbon material (C): a fluorinated carbon material in the form of particles or fibers.

Abstract: The present invention relates to an optical member including a TiO2-containing silica glass having: a TiO2 concentration of from 3 to 10% by mass; a Ti3+ concentration of 100 wt ppm or less; a thermal expansion coefficient at from 0 to 100° C., CTE0-100, of 0±150 ppb/° C.; and an internal transmittance in the wavelength range of 400 to 700 nm per a thickness of 1 mm, T400-700, of 80% or more, in which the optical member has a ratio of variation of Ti3+ concentration to an average value of the Ti3+ concentration, ?Ti3+/Ti3+, on an optical use surface, is 0.2 or less.

Abstract: To provide a novel fluorination treatment method whereby the surface of oxide glass can be treated for fluorination at low cost and with excellent adhesiveness. A method for treating the surface of oxide glass, which comprises contacting the surface of oxide glass with a gas of a fluorinating agent or a mixed gas having a fluorinating agent diluted with an inert gas, wherein the fluorinating agent is an elemental fluorine, or a fluorine compound capable of cleaving a bond between an oxygen atom and a metal atom in the framework of the oxide glass and forming a bond between a fluorine atom and the metal atom; and the concentration of hydrogen fluoride at the surface of oxide glass with which the fluorinating agent is in contact, is controlled to be at most 1 mol %.

Abstract: The present invention relates to a process for production of a synthetic quartz glass having a fluorine concentration of 1,000 mass ppm or more, the process comprising: (a) a step of depositing and growing quartz glass fine particles obtained by flame hydrolysis of a glass forming raw material onto a substrate, to thereby form a porous glass body; (b) a step of keeping the porous glass body in a reaction vessel that is filled with elemental fluorine (F2) or a mixed gas comprising elemental fluorine (F2) diluted with an inert gas and contains a solid metal fluoride, to thereby obtain a fluorine-containing porous glass body; and (c) a step of heating the fluorine-containing porous glass body to a transparent vitrification temperature, to thereby obtain a fluorine-containing transparent glass body.