Abstract: A gas detection system is for detecting the remaining amount of gas in a gas tank that stores a predetermined gas. The gas detection system includes: a gas detector that detects the predetermined gas; and a shutter (e.g., a pressure detector) that is connected between the gas tank and the gas detector and opens and closes a path of the predetermined gas from the gas tank to the gas detector.

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: An alkyl sulfate ester containing a carbonyl group or a salt thereof. The compound is represented by the following formula: R1—C(—O)—(CR22)n—(OR3)p—(CR42)q-L-OSO3X wherein R1, R2, R3, R4, L, X, n, p and q are as defined herein. Also disclosed is a production method for making the alkyl sulfate ester.

Abstract: A method for producing a fluoropolymer, which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1), the polymer (1) including a polymerized unit derived from a monomer CX2?CY(—CZ2—O—Rf-A), wherein X is the same or different and is —H or —F; Y is —H, —F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is —H, —F, an alkyl group, or a fluoroalkyl group; Rf is a C1-C40 fluorine-containing alkylene group or a C-C100 fluorine-containing alkylene group and having an ether bond; and A is —COOM, —SO3M, or —OSO3M, wherein M is —H, a metal atom, —NR74, imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, wherein R7 is H or an organic group, providing that at least one of X, Y, and Z contains a fluorine atom.

Abstract: A method for producing a fluoropolymer, which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1), the polymer (1) including a polymerized unit derived from a monomer CX2?CY(—CZ2—O—Rf-A), wherein X is the same or different and is —H or —F; Y is —H, —F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is —H, —F, an alkyl group, or a fluoroalkyl group; Rf is a C1-C40 fluorine-containing alkylene group or a C—C100 fluorine-containing alkylene group and having an ether bond; and A is —COOM, —SO3M, or —OSO3M, wherein M is —H, a metal atom, —NR74, imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, wherein R7 is H or an organic group, providing that at least one of X, Y, and Z contains a fluorine atom.

Abstract: A method for producing a fluoropolymer, which includes polymerizing a monomer (I) represented by the general formula (I) in an aqueous medium to produce the fluoropolymer of the monomer (I), wherein an oxygen concentration in a reaction system of the polymerization is maintained at 500 ppm by volume or less: CX2?CY—CF2—O—Rf-A ??General formula (I): wherein X and Y are independently H, F, CH3, or CF3, and at least one of X and Y is F; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is —COOM, —SO3M, —OSO3M, or —C(CF3)2OM, wherein M is H, a metal atom, NR74, imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, and R7 is H or an organic group.

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 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 being represented by the general formula (1): CR1R2R4—CR3R5—X-A, wherein R1 to R5 are each H or a monovalent substituent, with the proviso that at least one of R1 and R3 represents a group represented by the general formula: —Y—R6 and at least one of R2 and R3 represents a group represented by the general formula: —X-A or a group represented by the general formula: —Y—R6; and A is the same or different at each occurrence and is —COOM, —SO3M, or —OSO3M. Also disclosed is a surfactant for polymerization represented by the general formula (1), a method for producing a fluoropolymer using the surfactant, a composition including a fluoropolymer and the surfactant and a molded body including the composition.

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 being represented by the general formula (1): CR1R2R4—CR3R5—X-A, wherein R1 to R5 are each H or a monovalent substituent, with the proviso that at least one of R1 and R3 represents a group represented by the general formula: —Y—R6 and at least one of R2 and R5 represents a group represented by the general formula: —X-A or a group represented by the general formula: —Y—R6; and A is the same or different at each occurrence and is —COOM, —SO3M, or —OSO3M. Also disclosed is a surfactant for polymerization represented by the general formula (1), a method for producing a fluoropolymer using the surfactant and a composition including a fluoropolymer and the surfactant.

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 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: An object of the present disclosure is to provide, for example, a fluoropolymer electret material with hardness. The present disclosure relates to an electret material comprising a fluoropolymer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1): wherein R1 to R4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group; and the fluoropolymer has a mass average molecular weight of 1 million or more and 5 million or less, or 5000 or more and less than 20000.

Abstract: A sulfonic acid or carboxylic acid containing a carbonyl group, or a salt thereof represented by the following formula: R1—C(?O)—(CR22)n—(OR3)p—(CR42)q-L-A wherein R1, R2, R3, R4, n, p, q, A and L are as defined herein.

Abstract: A method for producing a fluoropolymer aqueous dispersion, including a step A of performing ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof on a pretreatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a polymer (I) including a polymerized unit (I) derived from a monomer represented by the following general formula (I), with the proviso that the fluoropolymer is other than the polymer (I): CX1X3?CX2R(—CZ1Z2-A0)m??(I) wherein X1 and X3 are each independently F, Cl, H, or CF3; X2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A0 is an anionic group; R is a linking group; Z1 and Z2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.

Abstract: A method for producing a fluoropolymer aqueous dispersion, including a step A of subjecting a pre-treatment aqueous dispersion containing a fluoropolymer obtained by polymerization in the presence of a hydrocarbon surfactant to ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof The ultrafiltration is performed using an ultrafiltration membrane having a molecular weight cutoff of 0.3×104 Da or more.

Abstract: A method for producing a composition including a step A of performing ultrafiltration, microfiltration, dialysis membrane treatment, or a combination thereof on a composition containing water and a fluoropolymer. The fluoropolymer is a polymer having a structural unit M3 derived from a monomer represented by general formula (1): CX2?CY(—CZ2—O—Rf-A)??(1) where X is the same or different and is —H or —F; Y is —H, —F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is —H, —F, an alkyl group, or a fluoroalkyl group; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is —COOM, —SO3M, —OSO3M, or —C(CF3)2OM, wherein M is as defined herein; provided that at least one of X, Y, and Z includes a fluorine atom.

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: 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 method for producing a carbonyl compound represented by formula (1): wherein R1 is hydrogen or an organic group; R2 is hydrogen or an organic group; and R3 is hydrogen or an organic group; or two or three of R1, R2, and R3 may be linked to form a ring that may have at least one substituent, the method comprising step A of oxidizing an olefin compound represented by formula (2): wherein symbols are as defined above, by an oxidizing agent in the presence of (a) a non-alcohol organic solvent, (b) water, (c) a metal catalyst, and (d) an additive represented by the formula: MXn, wherein M is an element belonging to any one of Group 1, Group 2, Group 13, Group 14, and Group 15 in the periodic table, or NR4, wherein R is hydrogen or a C1-10 organic group; X is halogen; and n is a number of 1 to 5.