The present invention relates to a fluorine-containing alternating copolymer macromonomer and a synthesis method thereof. The synthesis method comprises steps of: subjecting a fluorine-containing alternating copolymer to a reduction reaction at 60-100° C. in an organic solvent in the presence of a reducing agent and a first catalyst to obtain a reduction product; in the presence of a second catalyst, reacting the reduction product with a mercapto-monohydric alcohol in an organic solvent at 60-100° C., to obtain a hydroxyl-terminated fluorine-containing alternating copolymer; and in the presence of a third catalyst, reacting the hydroxyl-terminated fluorine-containing alternating copolymer with an acrylic monomer or acryloyl chloride monomer at 0-30° C., to obtain the fluorine-containing alternating copolymer macromonomer. In the present invention, a fluorine-containing alternating copolymer macromonomer is initially synthesized from a fluorine-containing alternating copolymer through polymer modification.

To provide a fluorinated copolymer, whereby it is possible to produce a crosslinked rubber article excellent in mold release properties.

The fluorinated copolymer of the present invention has units based on tetrafluoroethylene, units based on a perfluoro(alkyl vinyl ether), units based on a monomer having a fluorine atom and at least two polymerizable unsaturated bonds, and units based on a monomer having a nitrile group and a fluorine atom.

To provide a fluorinated copolymer, whereby it is possible to produce a crosslinked rubber article excellent in mold release properties.

The fluorinated copolymer of the present invention has units based on tetrafluoroethylene, units based on a perfluoro(alkyl vinyl ether), units based on a monomer having a fluorine atom and at least two polymerizable unsaturated bonds, and units based on a monomer having a nitrile group and a fluorine atom.

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 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 liquid repellent composition which can provide an article with good alcohol repellency is provided. A liquid repellent composition comprising a fluorinated polymer and an aqueous medium, wherein the fluorinated polymer comprises units based on a monomer a, units based on a monomer b and units based on a monomer c. Monomer a: a compound represented by CH.sub.2═CH—R.sup.f (wherein R.sup.f is a C.sub.1-8 perfluoroalkyl group). Monomer b: a fluorine-free nonionic surfactant having a polymerizable carbon-carbon double bond. Monomer c: another monomer copolymerizable with the monomer a and the monomer b.

A liquid repellent composition which can provide an article with good alcohol repellency is provided. A liquid repellent composition comprising a fluorinated polymer and an aqueous medium, wherein the fluorinated polymer comprises units based on a monomer a, units based on a monomer b and units based on a monomer c. Monomer a: a compound represented by CH.sub.2═CH—R.sup.f (wherein R.sup.f is a C.sub.1-8 perfluoroalkyl group). Monomer b: a fluorine-free nonionic surfactant having a polymerizable carbon-carbon double bond. Monomer c: another monomer copolymerizable with the monomer a and the monomer b.

A water- and oil-proofing composition stable under highly alkaline conditions is provided. A water- and oil-proofing composition comprising a fluorinated polymer and an aqueous medium, wherein the fluorinated polymer comprises units based on a monomer a and units based on a monomer b. Monomer a: a compound represented by CH.sub.2═CH—R.sup.f (wherein R.sup.f is a C.sub.1-8 perfluoroalkyl group). Monomer b: a compound having a polymerizable unsaturated group and a cationic group.

A water- and oil-proofing composition stable under highly alkaline conditions is provided. A water- and oil-proofing composition comprising a fluorinated polymer and an aqueous medium, wherein the fluorinated polymer comprises units based on a monomer a and units based on a monomer b. Monomer a: a compound represented by CH.sub.2═CH—R.sup.f (wherein R.sup.f is a C.sub.1-8 perfluoroalkyl group). Monomer b: a compound having a polymerizable unsaturated group and a cationic group.

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.