A method for producing a fluorine-containing elastomer, which includes carrying out an emulsion polymerization of a fluorine-containing monomer in an aqueous medium in the presence of (A) a fluorine-containing compound containing a functional group capable of reaction by radical polymerization and a hydrophilic group and (B) a hydrocarbon surfactant to provide a fluorine-containing elastomer.

Provided is a seal material having excellent non-adherence to metal surfaces. The seal material is formed of a cross-linked rubber that is obtained through cross-linking of a cross-linkable rubber composition containing a binary fluororubber, a carbon material, and a polyol cross-linker. The carbon material includes one or more carbon nanotubes. The cross-linked rubber has an adhesion strength of 2 N or less to a metal surface after being heated at 250° C. for 70 hours while in contact with the metal surface.

Provided is a seal material having excellent non-adherence to metal surfaces. The seal material is formed of a cross-linked rubber that is obtained through cross-linking of a cross-linkable rubber composition containing a binary fluororubber, a carbon material, and a polyol cross-linker. The carbon material includes one or more carbon nanotubes. The cross-linked rubber has an adhesion strength of 2 N or less to a metal surface after being heated at 250° C. for 70 hours while in contact with the metal surface.

An aqueous dispersion comprising a tetrafluoroethylene core-shell polymer and at least one surfactant corresponding to the general formula R.sub.10-[CH.sub.2CH.sub.20].sub.n[R.sub.20].sub.m-R.sub.3 wherein R.sub.1 represents a linear or branched aliphatic hydrocarbon group having at least 8 carbon atoms, preferably 8 to 18 carbon atoms, R2 represents an alkylene having 3 carbon atoms, R3 represents hydrogen, a C1-C3 alkyl group, or a C1-C3 hydroxyalkyl group, n has a value of 0 to 40, m has a value of 0 to 40 and the sum of n+m is at least 2, wherein the dispersion is free of fluorinated emulsifiers or contains them in an amount of less than 50 ppm based on the weight of the dispersion and wherein the core-shell polymer contains an outer shell of tetrafluoroethylene homopolymer. Further provided are methods of making the dispersions, coating compositions comprising the dispersions and article coated by the coating composition.

An aqueous dispersion comprising a tetrafluoroethylene core-shell polymer and at least one surfactant corresponding to the general formula R.sub.10-[CH.sub.2CH.sub.20].sub.n[R.sub.20].sub.m-R.sub.3 wherein R.sub.1 represents a linear or branched aliphatic hydrocarbon group having at least 8 carbon atoms, preferably 8 to 18 carbon atoms, R2 represents an alkylene having 3 carbon atoms, R3 represents hydrogen, a C1-C3 alkyl group, or a C1-C3 hydroxyalkyl group, n has a value of 0 to 40, m has a value of 0 to 40 and the sum of n+m is at least 2, wherein the dispersion is free of fluorinated emulsifiers or contains them in an amount of less than 50 ppm based on the weight of the dispersion and wherein the core-shell polymer contains an outer shell of tetrafluoroethylene homopolymer. Further provided are methods of making the dispersions, coating compositions comprising the dispersions and article coated by the coating composition.

A tube for transferring a liquid having a refractive index of 1.35 to 1.41. The tube contains a fluoropolymer, and the fluoropolymer has a melt flow rate of 3 to 150 g/10 min, and a light transmittance at a wavelength of 300 nm of 85% or higher. Also disclosed is a container including the tube, and a fragrance product including a transparent container accommodating the liquid and the tube for sucking up the liquid.

A tube for transferring a liquid having a refractive index of 1.35 to 1.41. The tube contains a fluoropolymer, and the fluoropolymer has a melt flow rate of 3 to 150 g/10 min, and a light transmittance at a wavelength of 300 nm of 85% or higher. Also disclosed is a container including the tube, and a fragrance product including a transparent container accommodating the liquid and the tube for sucking up the liquid.

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.

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.

The vinylidene-fluoride-based polymer composition according to the present invention comprises a vinylidene-fluoride-based polymer and a specific surfactant and contains no fluorinated surfactant, wherein the specific surfactant is contained in an amount of 10 ppm or larger but less than 100 ppm in terms of mass ppm of the solid components of the composition and has an HLB value of 10 or greater. The method for producing a vinylidene-fluoride-based polymer according to the present invention comprises emulsion-polymerizing specific monomers in an aqueous medium in the presence of a specific emulsifier and an initiator without using any fluorinated surfactant, the use amount of the emulsifier being 8.5 ppm or larger but less than 100 ppm in terms of mass ppm of the monomers.