Abstract: To provide a fluorinated elastic copolymer excellent in adhesion, processability, mechanical properties, heat resistance and chemical resistance. A fluorinated elastic copolymer having units based on a monomer (a), units based on a monomer (b) and optionally units based on a monomer (c), which has an iodine atom bonded to a terminal of a molecular chain and the unit based on the monomer (b) adjacent to the iodine atom, and which has a proportion of the units based on the monomer (b) of from 0.09 to 2.0 mol % to all units. Monomer (a): monomer selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene, a perfluoro(alkyl vinyl ether) and 2,3,3,3-tetrafluoropropene; monomer (b): a monomer having at least one type of functional group selected from the group consisting of an epoxy group, a hydroxy group, a carbonyl group-containing group and an isocyanate group; monomer (c): a monomer selected from the group consisting of ethylene and propylene.

Abstract: To provide a method for producing a fluorinated polymer which does not require an emulsifier as an essential component while an aqueous medium with little environmental burden is used.

Abstract: To provide a method for producing crosslinked rubber excellent in hardness and transparency. The method for producing crosslinked rubber of the present invention is a method for producing crosslinked rubber, which comprises crosslinking a fluorinated copolymer in a composition comprising the fluorinated copolymer, a crosslinking agent and a crosslinking co-agent, wherein the fluorinated copolymer is a copolymer having units based on tetrafluoroethylene and units based on a perfluoro(alkyl vinyl ether), the content of the units based on tetrafluoroethylene is from 65 to 90 mol % to all units of the fluorinated copolymer, in the composition, the content of the crosslinking agent is from 0.03 to 0.7 part by mass to 100 parts by mass of the fluorinated copolymer, the content of the crosslinking co-agent is from 0.1 to 2.5 parts by mass to 100 parts by mass of the fluorinated copolymer, and the hardness is from 65 to 100.

Abstract: To provide a fluorinated elastic copolymer having a low content of metal elements and being excellent in crosslinkability. This fluorinated elastic copolymer has iodine atoms and has units a based on tetrafluoroethylene, units b based on a monomer having one polymerizable unsaturated bond (but excluding tetrafluoroethylene), and units c based on a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the metal content is at least 0.3 ppm by mass and at most 20.0 ppm by mass.

Abstract: To provide a fluorinated copolymer excellent in low temperature properties and crosslinking property as a fluororubber, and a method for producing it. A fluorinated copolymer which has units based on tetrafluoroethylene, units based on propylene and units based on a compound represented by the following formula 1, and which has either one or both of iodine atoms and bromine atoms: CF2?CFO(Rf1O)nRf2??formula 1 wherein Rf1 is a C1-3 perfluoroalkylene group, Rf2 is a C1-6 perfluoroalkyl group, n is an integer of from 1 to 4, and in a case where n is from 2 to 4, a plurality of Rf1 may be the same or different.

Abstract: To provide a fluorinated elastic copolymer excellent in adhesion, processability, mechanical properties, heat resistance and chemical resistance. A fluorinated elastic copolymer having units based on a monomer (a), units based on a monomer (b) and optionally units based on a monomer (c), which has an iodine atom bonded to a terminal of a molecular chain and the unit based on the monomer (b) adjacent to the iodine atom, and which has a proportion of the units based on the monomer (b) of from 0.09 to 2.0 mol % to all units. Monomer (a): monomer selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene, a perfluoro(alkyl vinyl ether) and 2,3,3,3-tetrafluoropropene; monomer (b): a monomer having at least one type of functional group selected from the group consisting of an epoxy group, a hydroxy group, a carbonyl group-containing group and an isocyanate group; monomer (c): a monomer selected from the group consisting of ethylene and propylene.

Abstract: To provide a fluorinated elastic copolymer composition whereby it is possible to obtain a crosslinked rubber article which is excellent in low temperature characteristics and which has sufficient hardness; and a crosslinked rubber article which is excellent in low temperature characteristics and which has sufficient hardness. The fluorinated elastic copolymer composition comprises a fluorinated elastic copolymer having units based on tetrafluoroethylene and units based on CF2?CFORf1 (wherein Rf1 is a C1-10 perfluoroalkyl group), and an organic silicon compound which has a perfluoropolyether chain and at least two polymerizable unsaturated bonds.

Abstract: To provide a fluorinated elastic copolymer and a fluorinated elastic copolymer composition, whereby it is possible to obtain a crosslinked rubber article which has practically sufficient rubber physical properties and which is, at the same time, excellent in low-temperature characteristics; a crosslinked rubber article; and a method for producing a fluorinated elastic copolymer. The fluorinated elastic copolymer comprises units based on tetrafluoroethylene, units based on CF2?CFORf1 (Rf1 is a C1-10 perfluoroalkyl group), units based on CF2?CF(OCF2CF2)n—(OCF2)m?OR f2 (Rf2 is a C1-4 perfluoroalkyl group, n is an integer of from 0 to 3, m is an integer of from 0 to 4, and n+m is an integer of from 1 to 7), and units based on a fluorinated monomer having at least two polymerizable unsaturated bonds.

Abstract: To provide a fluorinated elastic copolymer in which the contents of metal elements and chloride ions are low, and a method for producing a fluorinated elastic copolymer, whereby it is possible to obtain a fluorinated elastic copolymer in which the contents of metal elements and chloride ions are low. A fluorinated elastic copolymer in which the content of metal elements is at most 20.0 ppm by mass and the content of chloride ions is at most 1 ppm by mass; and a method for producing a fluorinated elastic copolymer, which comprises coagulating a fluorinated elastic copolymer in a latex containing the fluorinated elastic copolymer by using an acid containing no metal elements or no chloride ions, and washing the coagulated fluorinated elastic copolymer with a liquid medium having a content of metal elements of at most 2.0 ppm by mass and a content of chloride ions of at most 2 ppm by mass.

Abstract: To provide a fluorinated elastic copolymer having a low content of metal elements and being excellent in crosslinkability. This fluorinated elastic copolymer has iodine atoms and has units a based on tetrafluoroethylene, units b based on a monomer having one polymerizable unsaturated bond (but excluding tetrafluoroethylene), and units c based on a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the metal content is at least 0.3 ppm by mass and at most 20.0 ppm by mass.

Abstract: To provide a perfluoroelastomer, which is excellent in low temperature properties, which does not lose value as a rubber and which is free from a decrease of the productivity, a perfluoroelastomer composition, a crosslinked rubber product, and a method for producing a perfluoroelastomer. A perfluoroelastomer comprising structural units (a) derived from tetrafluoroethylene, structural units (b) derived from a perfluoroalkyl vinyl ether represented by the formula (1) (such as perfluoromethyl vinyl ether) and structural units (c) derived from a perfluorooxaalkyl vinyl ether represented by the formula (2) (such as CF2?CFOCF2CF2OCF2CF2OCF2CF3).

Abstract: Provided is a process for producing a fluorinated copolymer which is capable of providing an ion exchange membrane which can suppress a decrease in current efficiency by impurities in an aqueous alkali chloride solution as a raw material on electrolysis of the alkali chloride aqueous solution. Also provided is a process for producing a fluorinated copolymer that comprises washing a fluorinated copolymer comprising a fluorinated monomer having a carboxylic acid type functional group and a fluorinated olefin, with a washing solvent containing a fluorinated solvent at a temperature of at least 40° C. and at most a boiling point of the washing solvent.

Abstract: To provide a fluorinated copolymer which is capable of providing an ion exchange membrane having little adverse effect due to impurities in an alkali chloride aqueous solution on electrolysis of the alkali chloride aqueous solution. To use a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, wherein the proportion of components having a common logarithm (log M) of a molecular weight M being from 2.0 to 3.5 is at most 10 mass % per 100 mass % of components having a common logarithm (log M) of a molecular weight M being at least 2.0, contained in a CClF2CF2CClFH soluble content.

Abstract: To provide a perfluoroelastomer, which is excellent in low temperature properties, which does not lose value as a rubber and which is free from a decrease of the productivity, a perfluoroelastomer composition, a crosslinked rubber product, and a method for producing a perfluoroelastomer. A perfluoroelastomer comprising structural units (a) derived from tetrafluoroethylene, structural units (b) derived from a perfluoroalkyl vinyl ether represented by the formula (1) (such as perfluoromethyl vinyl ether) and structural units (c) derived from a perfluorooxaalkyl vinyl ether represented by the formula (2) (such as CF2?CFOCF2CF2OCF2CF2OCF2CF3).

Abstract: To provide a process for producing a fluorinated copolymer which is capable of providing an ion exchange membrane which can suppress a decrease in current efficiency by impurities in an aqueous alkali chloride solution as a raw material on e.g. electrolysis of the alkali chloride aqueous solution. A process for producing a fluorinated copolymer, which comprises a step of washing a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, by a washing solvent containing a fluorinated solvent, at a temperature of at least 40° C. and at most a boiling point of the washing solvent.

Abstract: To provide a fluorinated copolymer which is capable of providing an ion exchange membrane having little adverse effect due to impurities in an alkali chloride aqueous solution on electrolysis of the alkali chloride aqueous solution. To use a fluorinated copolymer of a fluorinated monomer having a carboxylic acid type functional group with a fluorinated olefin, wherein the proportion of components having a common logarithm (log M) of a molecular weight M being from 2.0 to 3.5 is at most 10 mass % per 100 mass % of components having a common logarithm (log M) of a molecular weight M being at least 2.0, contained in a CClF2CF2CClFH soluble content.