A coating composition which contains a fluorinated polymer having a unit (1) represented by —[CX.sup.1X.sup.2—CY.sup.1(Rf.sup.1—COOM.sup.1)]— and a fluorinated compound represented by CX.sup.3X.sup.4═CY.sup.2(Rf.sup.2—COOM.sup.2), wherein the content of the fluorinated compound is from 0.1 to 8.0 parts by mass per 100 parts by mass of the fluorinated polymer. X.sup.1, X.sup.2, X.sup.3 and X.sup.4 are H, F or Cl, Y.sup.1 and Y.sup.2 are H, F, Cl, a methyl group or a trifluoromethyl group, Rf.sup.1 and Rf.sup.2 are a perfluoroalkylene group which may contain an etheric oxygen atom between carbon-carbon atoms, or an oxyperfluoroalkylene group which may contain an etheric oxygen atom between carbon-carbon atoms, —COOM.sup.1 is —COOH or —COOZ.sup.1, and —COOM.sup.2 is —COOH or —COOZ.sup.2 (wherein Z.sup.1 and Z.sup.2 are an ammonium ion in which the hydrogen atom may be substituted). The coating composition is suitable for forming a thin antireflection coating layer without increasing its refractive index.

A process for reducing the amount of soluble polymeric fractions in a sulfonyl fluoride polymer. The process comprises contacting the sulfonyl fluoride polymer with a fluorinated fluid followed by separation of the polymer from the fluid. The fluorinated fluid is selected from hydrofluoroethers and hydrofluoropolyethers. The invention further relates to sulfonyl fluoride polymers obtainable by the process and having a heat of fusion not exceeding 4 J/g and containing less than 15% by weight of polymeric fractions having an average content of monomeric units comprising a sulfonyl functional group exceeding 24 mole %. The sulfonyl fluoride polymers so obtained are particularly suitable for the preparation of ionomeric membranes for use in electrochemical devices.

A process for reducing the amount of soluble polymeric fractions in a sulfonyl fluoride polymer. The process comprises contacting the sulfonyl fluoride polymer with a fluorinated fluid followed by separation of the polymer from the fluid. The fluorinated fluid is selected from hydrofluoroethers and hydrofluoropolyethers. The invention further relates to sulfonyl fluoride polymers obtainable by the process and having a heat of fusion not exceeding 4 J/g and containing less than 15% by weight of polymeric fractions having an average content of monomeric units comprising a sulfonyl functional group exceeding 24 mole %. The sulfonyl fluoride polymers so obtained are particularly suitable for the preparation of ionomeric membranes for use in electrochemical devices.

A method of producing a homopolymer or random copolymer of hydroxyl group-containing vinyl ether by polymerizing a monomer component comprising at least one hydroxyl group-containing vinyl ether using an oil-soluble radical polymerization initiator in the absence or presence of a solvent.

A method of producing a homopolymer or random copolymer of hydroxyl group-containing vinyl ether by polymerizing a monomer component comprising at least one hydroxyl group-containing vinyl ether using an oil-soluble radical polymerization initiator in the absence or presence of a solvent.

The invention relates to a method for preparing a vinyl ether polymer by photo-initiated polymerization, which comprises the step of: under a protective atmosphere, performing photo-initiated polymerization on a vinyl ether monomer in the presence of an organic halogenated hydrocarbon and manganese carbonyl under irradiation of light having a wavelength of 365-550 nm at −25° C. to 25° C., to obtain a vinyl ether polymer after the reaction is completed. In the method, a vinyl ether monomer is subjected to cationic polymerization in the presence of manganese carbonyl and an organic halogenated hydrocarbon under visible light, to prepare a vinyl ether polymer with controlled molecular weight and narrow molecular weight distribution.

The invention relates to a method for preparing a vinyl ether polymer by photo-initiated polymerization, which comprises the step of: under a protective atmosphere, performing photo-initiated polymerization on a vinyl ether monomer in the presence of an organic halogenated hydrocarbon and manganese carbonyl under irradiation of light having a wavelength of 365-550 nm at −25° C. to 25° C., to obtain a vinyl ether polymer after the reaction is completed. In the method, a vinyl ether monomer is subjected to cationic polymerization in the presence of manganese carbonyl and an organic halogenated hydrocarbon under visible light, to prepare a vinyl ether polymer with controlled molecular weight and narrow molecular weight distribution.

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 0.3×10.sup.4 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):

CX.sub.2═CY(—CZ.sub.2—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.

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):

CX.sub.2═CY(—CZ.sub.2—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, —SO.sub.3M, —OSO.sub.3M, or —C(CF.sub.3).sub.2OM, wherein M is as defined herein; provided that at least one of X, Y, and Z includes a fluorine atom.

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,

CX.sup.1X.sup.3═CX.sup.2R(—VZ.sup.1Z.sup.2-A.sup.0).sub.m   (I)

wherein X.sup.1 and X.sup.3 are each independently F, Cl, H, or CF.sub.3; X.sup.2 is H, F, an alkyl group, or a fluorine-containing alkyl group; A.sup.0 is an anionic group; R is a linking group; Z.sup.1 and Z.sup.2 are each independently H, F, an alkyl group, or a fluorine-containing alkyl group; and m is an integer of 1 or more.