Abstract: A method for producing polytetrafluoroethylene, which includes polymerizing tetrafluoroethylene in an aqueous medium in the presence of a nucleating agent and a hydrocarbon anionic surfactant to obtain polytetrafluoroethylene. A total amount of the nucleating agent and the hydrocarbon anionic surfactant at the initiation of polymerization is more than 50 ppm based on the aqueous medium.

Abstract: A method for producing a fluoropolymer aqueous dispersion, the method including concentrating a composition comprising a polymer (I) containing a polymerization unit (I) derived from a monomer (I) represented by the general formula (I), a fluoropolymer excluding the polymer (I), a nonionic surfactant, a fluorine-free anionic surfactant, and an aqueous medium to thereby obtain an aqueous dispersion containing the fluoropolymer, 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, 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 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 aircraft component is used for an aircraft gas-turbine engine. The aircraft component includes an annular part, a flange, and a boss. The annular part has an outer circumferential surface. The flange is formed at one end portion of the annular part in an axial direction. The boss projects from the outer circumferential surface of the annular part to the radial direction. On a section cut along an axial direction of the annular part, the outer circumferential surface of the annular part between the flange and the boss has a taper part that is formed into a tapered shape in which plate thickness becomes thicker from the flange toward the boss.

Abstract: Provided is a method for producing polytetrafluoroethylene, which includes polymerizing tetrafluoroethylene in an aqueous medium in the presence of a nucleating agent and a polymer (I) containing a polymerization unit (I) based on a monomer represented by the general formula (I) to obtain polytetrafluoroethylene: 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, which includes: polymerizing a monomer (I) represented by the general formula (I) below in an aqueous medium substantially in the absence of a fluorine-containing surfactant (except for the monomer (I) represented by the general formula (I)) to obtain a crude composition containing a polymer of the monomer (I); removing a dimer and a trimer of the monomer (I) contained in the crude composition from the crude composition to obtain a polymer (I) in which the content of the dimer and trimer of the monomer (I) is 1.0% by mass or less based on the polymer (I); and polymerizing a fluoromonomer in an aqueous medium in the presence of the polymer (I) to obtain a fluoropolymer: CX1X3?CX2R(—CZ1Z2-A0)m??(I) wherein X1 and X3, X2, A0, R, Z1 and Z2 are as defined herein.

Abstract: A PTFE aqueous dispersion having low viscosity at high temperature. The PTFE aqueous dispersion contains PTFE and a nonionic surfactant, has a PTFE solid concentration of 50 to 70% by mass, is substantially free from a fluorine-containing surfactant, and has a viscosity at 55° C. of 50 mPa·s or lower. Also disclosed is a method for producing the PTFE aqueous dispersion, a coating film obtained by applying the PTFE aqueous dispersion, an impregnated film obtained by impregnating the PTFE aqueous dispersion, and a coated article containing a coating film obtained by applying the PTFE aqueous dispersion.

Abstract: Provided is a method for producing a fluoropolymer, including a polymerization step of polymerizing a fluoromonomer in an aqueous medium having a pH of 4.0 or more in the presence of a hydrocarbon surfactant and a polymerization initiator to obtain a fluoropolymer.

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 composition containing a polytetrafluoroethylene, a polymer (I) containing a polymerization unit (I) based on a monomer represented by the general formula (I), a nonionic surfactant, and an aqueous medium, wherein a content of the polytetrafluoroethylene in the composition is 10% by mass or more based on the composition, and a content of the nonionic surfactant in the composition is 1.0% by mass or more based on the polytetrafluoroethylene, CX1X3?CX2R(—VZ1Z2-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 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 polytetrafluoroethylene includes a step of polymerizing tetrafluoroethylene in an aqueous medium in the presence of a hydrocarbon surfactant and a polymerization initiator to obtain polytetrafluoroethylene and a step of adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator after the initiation of polymerization.

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 composition including a polytetrafluoroethylene and a polymer (I) containing a polymerization unit (I) based on a monomer represented by the following general formula (I), the composition having a standard specific gravity of 2.200 or less: CX1X3?CX2R(—CZ1Z2-A0)m ??(I) wherein X1 and X3 are each independently F, Cl, H, or CF3; A0 is an anionic group; X2 is H, F, an alkyl group, or a fluorine-containing alkyl 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.