Abstract: Composition including (a) a fluoropolymer; and (b1) at least one of a compound represented by the formula (4) ((H—(CF2)7—COO)pM1) or the formula (4?) ((H—(CF2)8—COO)pM1) of the present disclosure, both respectively in an amount of 100 ppb or less relative to the fluoropolymer, or (b2) at least one of a compound represented by the formula (5) ((H—(CF2)13—COO)pM1) or the formula (5?) ((H—(CF2)14—COO)pM1) of the present disclose, both respectively in an amount of 100 ppb or less relative to the fluoropolymer.

Abstract: A composition including a fluoropolymer and substantially free from a compound represented by the following formula (3): (H—(CF2)8—SO3)qM2, wherein M2 is H, a metal atom, NR54, imidazolium optionally containing a substituent, pyridinium optionally containing a substituent, or phosphonium optionally containing a substituent; R5s are each H or an organic group and are the same as or different from each other; and q is 1 or 2.

Abstract: A method for producing a fluoropolymer, which includes polymerizing a fluoromonomer in a solvent to produce the fluoropolymer. The solvent contains a fluorine-containing ether compound (1) represented by formula:R1—O—R2 wherein R1 represents a partially fluorinated alkyl group, and R2 represents a non-fluorinated alkyl group, a partially fluorinated alkyl group, or a completely fluorinated alkyl group, and in the solvent, a content of a fluorine-containing olefin compound (2) represented by formula:R3—CF?CF—R4—O—R2 wherein R3 represents H, F, a partially fluorinated alkyl group, or a completely fluorinated alkyl group, R4 represents a single bond, a partially fluorinated alkylene group, or a completely fluorinated alkylene group, and R2 is the same as described above, is 1.00% by mass or less based on a content of the fluorine-containing ether compound (1), and wherein the fluoromonomer is selected from tetrafluoroethylene, chlorotrifluoroethylene, and vinylidene fluoride.

Abstract: A binder for a secondary battery containing a fluorine-containing polymer (A) and polyvinylidene fluoride (B). The fluorine-containing polymer (A) contains a polymerized unit based on vinylidene fluoride, a polymerized unit based on tetrafluoroethylene, and a polymerized unit based on a monomer (2-2) represented by the following formula (2-2): wherein R5, R6, and R7 are each independently a hydrogen atom or a C1-C8 hydrocarbon group; R8 is a C1-C8 hydrocarbon group; and Y1 is an inorganic cation or an organic cation. Also disclosed is an electrode mixture and an electrode for a secondary battery including the binder, and a secondary battery including the electrode.

Abstract: A sulfuric acid ester containing a plurality of carbonyl groups or a salt thereof, and a surfactant. The sulfuric acid ester is a compound represented by the following formula: R1—C(?O)—R2—C(?O)—R3—OSO3X wherein R1, R2 and R3 are defined herein; X is H, a metal atom, NR44, imidazolium optionally containing a substituent, pyridinium optionally containing a substituent, or phosphonium optionally containing a substituent, where R4s are each H or an organic group and are the same as or different from each other; and any two of R1, R2, and R3 optionally bind to each other to form a ring. Also disclosed is a surfactant containing the sulfuric acid ester and an aqueous dispersant containing the sulfuric acid ester.

Abstract: A composition including a fluoropolymer and substantially free from a compound represented by the following formula (3): (H—(CF2)8—SO3)qM2, wherein M2 is H, a metal atom, NR54, imidazolium optionally containing a substituent, pyridinium optionally containing a substituent, or phosphonium optionally containing a substituent; R5s are each H or an organic group and are the same as or different from each other; and q is 1 or 2.

Abstract: Provided is a copolymer consisting essentially of ethylene units, tetrafluoroethylene units, and hexafluoropropylene units, wherein a molar ratio (Et units/TFE units) of the ethylene (Et) units to the tetrafluoroethylene (TFE) units is 52.0/48.0 to 56.0/44.0, and a content of the hexafluoropropylene units is 19.0 to 21.0 mol % based on the total monomer units constituting the copolymer.

Abstract: A method for producing a fluoropolymer of the invention which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a surfactant to provide a fluoropolymer. The surfactant includes at least one selected from the group consisting of a surfactant represented by R1a—CO—R2a—CO—R3a-Aa and a surfactant represented by R1b—CO—(CR2b2)n—(OR3b)p—(CR4b2)q-L-Ab.

Abstract: Provided is a method for producing an injection molded article for obtaining an injection molded article by injection molding a copolymer using an injection molding machine and a mold having a hot runner, wherein the copolymer is a copolymer containing tetrafluoroethylene unit and a fluoroalkyl vinyl ether unit, and the number of functional groups of the copolymer is 100 or less per 106 main-chain carbon atoms.

Abstract: A secondary battery separator including a porous substrate and a porous film firmly bonded to each other, the porous film being disposed on or above the porous substrate. The porous film contains a fluorine-containing polymer that contains a polymerized unit based on vinylidene fluoride, a polymerized unit based on tetrafluoroethylene, and a polymerized unit based on a monomer represented by the following formula (2-2): R5R6C?CR7R8CO2Y1??(2-2) wherein R5, R6, and R7 are each independently a hydrogen atom or a C1-C8 hydrocarbon group; R8 is a C1-C8 hydrocarbon group; and Y1 is an inorganic cation and/or an organic cation. Also disclosed is a secondary battery including the secondary battery separator; a positive electrode; a negative electrode; and a non-aqueous electrolyte solution.

Abstract: A magnet wire including a conductor and an insulating coating formed on an outer periphery of the conductor. The insulating coating contains a copolymer containing a tetrafluoroethylene unit and a fluoroalkyl vinyl ether unit. The copolymer has a melt flow rate of 10 to 60 g/10 min, and the copolymer has a fluoroalkyl vinyl ether unit content of 6.2 to 8.0% by mass based on a total content of monomer units.

Abstract: The present disclosure provides a welded body having a connecting structure formed by welding a first molded body and a second molded body, wherein the first and second molded bodies contain at least one copolymer selected from the group consisting of a tetrafluoroethylene/fluoro(alkyl vinyl ether) copolymer and a tetrafluoroethylene/hexafluoropropylene copolymer, and wherein the connecting structure has a liquid contact surface to be in contact with a liquid having a solubility parameter of 14 to 35 (MPa)1/2, a welded part formed in the connecting structure is not exposed to the liquid contact surface, and the number of particles of 30 nm or larger to be eluted from the liquid contact surface in the connecting structure is 1,000 particles/ml or less.

Abstract: A surfactant for polymerization including at least one selected from a surfactant represented by R1a—CO—R2a—CO—R3a—OSO3Xa and a surfactant represented by R1b—CO—(CR2b2)n—(OR3b)p—(CR4b2)q-L-OSO3Xb, wherein R1a, R2a, R3a, Xa, R1b, R2b, R3b, R4b, L and Xb are as defined herein. Also disclosed is a composition containing a fluoropolymer and the at least one surfactant, a composition containing a fluoropolymer and a compound represented by (H—(CF2)8—SO3)qM2, where M2 is as defined herein, and a molded article made from the composition containing a fluoropolymer and the compound represented by (H—(CF2)8—SO3)qM2.

Abstract: Provided is a tube comprising a tetrafluoroethylene/fluoroalkyl vinyl ether copolymer, wherein the tube inner surface has a surface roughness Ra of 5 nm or less measured by atomic force microscopy (AFM) with an evaluation length set to 3 ?m, and the tube has an amount of metals eluted from the tube inner surface of 0.30 ng/cm2 or less.

Abstract: A method for producing a fluoropolymer which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a surfactant to provide a fluoropolymer. The surfactant includes at least one selected from the group consisting of a surfactant represented by R1a—CO—R2a—CO—R3a—OSO3Xa and a surfactant represented by R1b—CO—(CR2b2)n—(OR3b)p—(CR4b2)q-L-OSO3Xb.

Abstract: A sulfuric acid ester containing a plurality of carbonyl groups or a salt thereof, and a surfactant. The sulfuric acid ester is a compound represented by the following formula: R1—C(?O)—R2—C(?O)—R3—OSO3X wherein R1, R2 and R3 are defined herein; X is H, a metal atom, NR44, imidazolium optionally containing a substituent, pyridinium optionally containing a substituent, or phosphonium optionally containing a substituent, where R4s are each H or an organic group and are the same as or different from each other; and any two of R1, R2, and R3 optionally bind to each other to form a ring. Also disclosed is a surfactant containing the sulfuric acid ester and an aqueous dispersant containing the sulfuric acid ester.

Abstract: A sulfuric acid ester containing a plurality of carbonyl groups or a salt thereof, and a surfactant. The sulfuric acid ester is a compound represented by the following formula: R1—C(?O)—R2—C(?O)—R3—OSO3X wherein R1, R2 and R3 are as defined herein; X is H, a metal atom, NR44, imidazolium optionally containing a substituent, pyridinium optionally containing a substituent, or phosphonium optionally containing a substituent, where R4s are each H or an organic group and are the same as or different from each other; and any two of R1, R2, and R3 optionally bind to each other to form a ring.

Abstract: A method for producing a fluoropolymer which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a surfactant to provide a fluoropolymer. The surfactant includes at least one selected from the group consisting of a surfactant represented by R1a—CO—R2 a—CO—R3a—OSO3Xa and a surfactant represented by R1b—CO—(CR2b2)n—(OR3b)p—(CR4b2)q-L-OSO3Xb.

Abstract: A method for producing a fluoropolymer of the invention which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a surfactant to provide a fluoropolymer. The surfactant includes at least one selected from the group consisting of a surfactant represented by R1a—CO—R2a—CO—R3a-Aa and a surfactant represented by R1b—CO—(CR2b2)n—(OR3b)p—(CR4b2)q-L-Ab.

Abstract: A binder and an electrode mixture for a secondary battery. The binder contains a fluorine-containing polymer containing a polymerized unit based on vinylidene fluoride, a polymerized unit based on tetrafluoroethylene, and a polymerized unit based on a monomer (2-2) represented by the following formula (2-2): R5R6C?CR7R8CO2Y1??(2-2) wherein R5, R6, and R7 are each independently a hydrogen atom or a C1-C8 hydrocarbon group; R8 is a C1-C8 hydrocarbon group; and Y1 is an inorganic cation and/or an organic cation.