Abstract: A method for producing a fluoropolymer which method includes polymerizing a perfluoromonomer in an aqueous medium in the presence of a polymer (1) to obtain a fluoropolymer, wherein the content of a polymerized unit derived from the perfluoromonomer in the fluoropolymer is 90 mol % or more based on all polymerized units of the fluoropolymer, the polymer (1) is a polymer of a monomer (1) represented by the general formula (1): CF2?CF—O—R-(Rf-SO3M)m, a polymerized unit (1) derived from the monomer (1) in the polymer (1) is 50% by mass or more based on all polymerized units of the polymer (1), and the content of a dimer and a trimer of the monomer (1) in the polymer (1) is 1.0% by mass or less based on the polymer (1).

Abstract: The present disclosure provides a method for producing a perfluoroelastomer aqueous dispersion by polymerizing a perfluoromonomer in the presence of a polymer (1) and an aqueous medium to produce an aqueous dispersion of a perfluoroelastomer, the polymer (1) containing a polymerization unit (1) based on a monomer (1) represented by a general formula (1) and the polymer (1) having an ion exchange capacity of 1.50 meq/g or more.

Abstract: Provided is a method for producing a fluorine-containing polymer, comprising polymerizing a fluorine-containing monomer in the presence of a fluorine-free compound (1) represented by general formula (1), a polymerization initiator, and an aqueous medium to produce the fluorine-containing polymer: CX1X2?CX3—R—Z??General formula (1): wherein X1, X2, and X3 are each independently H or an alkyl group; R is a single bond or an alkylene group; the total number of carbon atoms of X1, X2, X3, and R is 0 to 5; Z is —SO3M, —OSO3M, —P(?O)(OM)2, —OP(O)(OM)2, or —B(OM)2; M is H, a metal atom, NR14, optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium; and R1 is independently H or an organic group, and any two R1 may be bonded to each other to form a ring.

Abstract: The present disclosure provides a method for producing a fluoropolymer, the method includes polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1) to obtain a fluoropolymer, wherein the polymer (1) is a polymer of a monomer (1) represented by the general formula (1) below, in which the content of a dimer and a trimer of the monomer (1) is 1.0% by mass or less based on the polymer (1): CF2?CF—R—CZ1Z1-A0 ??(1) wherein R is a linking group; Z1 and Z2 are each independently F or CF3; and A0 is an anionic group.

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 method for producing a perfluoroelastomer, which includes carrying out polymerization of a perfluoromonomer in an aqueous medium in the presence of a polymer (1) having a number average molecular weight of 0.3×104 or more to provide a perfluoroelastomer, the polymer (1) containing a polymerized unit (1) derived from a monomer represented by the following general formula (1): CX2?CY(—CZ2—O—Rf-A) ??(1) wherein X, Y, Z, Rf and A are as defined herein, with the proviso that at least one of X, Y, and Z contains a fluorine atom.

Abstract: The present invention provides a sealing material having excellent plasma resistance, sealing property and non-sticking property, parts for plasma treating equipment having the sealing material, and a process for preparing the sealing material. The sealing material comprises a fluoroelastomer sealing material and a coating film formed by using an inorganic material on the surface of the fluoroelastomer sealing material, wherein a ratio of weight reduction of the sealing material after dipping it in perfluoro tri-n-butylamine at 60° C. for 70 hours and then taking it out and drying it at 90° C. for 5 hours, at 125° C. for 5 hours, and then at 200° C. for 10 hours, is not more than 0.4% by weight.