A fluorine-containing compound represented by the formula 1, ##STR00001## where R.sup.1 is a methyl group or trifluoromethyl group, each of R.sup.2 and R.sup.3 is independently a hydrogen atom or a group containing (a) a hydrocarbon group having a straight-chain, branched or ring form and having a carbon atom number of 1-25 or (b) an aromatic hydrocarbon group, the group optionally containing at least one of a fluorine atom, an oxygen atom and a carbonyl bond, l is an integer of from 0 to 2, each of m and n is independently an integer of 1-5 to satisfy an expression of m+n6, and when at least one of R.sup.1, R.sup.2 and R.sup.3 is in a plural number, the at least one of R.sup.1, R.sup.2 and R.sup.3 may be identical with or different from each other.

A fluorine-containing compound represented by the formula 1, ##STR00001## where R.sup.1 is a methyl group or trifluoromethyl group, each of R.sup.2 and R.sup.3 is independently a hydrogen atom or a group containing (a) a hydrocarbon group having a straight-chain, branched or ring form and having a carbon atom number of 1-25 or (b) an aromatic hydrocarbon group, the group optionally containing at least one of a fluorine atom, an oxygen atom and a carbonyl bond, l is an integer of from 0 to 2, each of m and n is independently an integer of 1-5 to satisfy an expression of m+n6, and when at least one of R.sup.1, R.sup.2 and R.sup.3 is in a plural number, the at least one of R.sup.1, R.sup.2 and R.sup.3 may be identical with or different from each other.

A fluorine-containing compound represented by the formula 1, ##STR00001## where R.sup.1 is a methyl group or trifluoromethyl group, each of R.sup.2 and R.sup.3 is independently a hydrogen atom or a group containing (a) a hydrocarbon group having a straight-chain, branched or ring form and having a carbon atom number of 1-25 or (b) an aromatic hydrocarbon group, the group optionally containing at least one of a fluorine atom, an oxygen atom and a carbonyl bond, l is an integer of from 0 to 2, each of m and n is independently an integer of 1-5 to satisfy an expression of m+n6, and when at least one of R.sup.1, R.sup.2 and R.sup.3 is in a plural number, the at least one of R.sup.1, R.sup.2 and R.sup.3 may be identical with or different from each other.

A method for preparing a fluoropolymer aqueous dispersion, including: step (A) of preparing a fluoropolymer aqueous dispersion comprising a fluoropolymer having at least one selected from the group consisting of SO.sub.2Y and COOR (wherein Y is a halogen, and R is a C1 to C4 alkyl) by emulsion polymerization; step (B) of heating the fluoropolymer aqueous dispersion to 50 C. or higher; and step (C) of contacting the fluoropolymer aqueous dispersion with an ion exchange resin for cation exchange after step (B), thereby providing a purified fluoropolymer aqueous dispersion, the fluoropolymer aqueous dispersion being adjusted to pH 7 or lower from the end of the polymerization in step (A) to the end of step (C).

A method for preparing a fluoropolymer aqueous dispersion, including: step (A) of preparing a fluoropolymer aqueous dispersion comprising a fluoropolymer having at least one selected from the group consisting of SO.sub.2Y and COOR (wherein Y is a halogen, and R is a C1 to C4 alkyl) by emulsion polymerization; step (B) of heating the fluoropolymer aqueous dispersion to 50 C. or higher; and step (C) of contacting the fluoropolymer aqueous dispersion with an ion exchange resin for cation exchange after step (B), thereby providing a purified fluoropolymer aqueous dispersion, the fluoropolymer aqueous dispersion being adjusted to pH 7 or lower from the end of the polymerization in step (A) to the end of step (C).

Disclosed is an integrated fluorine gasket manufactured by injection molding for hydrogen fuel cells. In particular, a fluorine compound having a fluorine content of about 60 to 75 parts by weight based on 100 parts by weight of a fluoroelastomer is disposed in a gasket. The resulting fluorine gasket is integrated with a thin bipolar plate having a thickness of about 200 m or less to have a thickness of about 750 m or less by injection molding on the thin bipolar plate and by cross-linking.

Disclosed is an integrated fluorine gasket manufactured by injection molding for hydrogen fuel cells. In particular, a fluorine compound having a fluorine content of about 60 to 75 parts by weight based on 100 parts by weight of a fluoroelastomer is disposed in a gasket. The resulting fluorine gasket is integrated with a thin bipolar plate having a thickness of about 200 m or less to have a thickness of about 750 m or less by injection molding on the thin bipolar plate and by cross-linking.

Anionic surfactants have a formula:

R.sub.fSO.sub.2N(H)CH.sub.2CH(CH.sub.3)OH; or

R.sub.fSO.sub.2N(H)(CH.sub.2CH.sub.2O).sub.xH, where x is an integer from 2-6. R.sub.f is a fluoroalkyl group having 3 to 8 carbon atoms. Neutral surfactants having a formula:

R.sub.fSO.sub.2N[CH.sub.2CH(CH.sub.3)OH].sub.2;(a)

R.sub.fSO.sub.2N[CH.sub.2CH(CH.sub.3)OH][(CH.sub.2CH.sub.2O).sub.nH], where n is an integer from 1-6;(b)

R.sub.fSO.sub.2N(R)[(CH.sub.2CH.sub.2O).sub.pH], where p is an integer from 2-6, and R is an alkyl group having 1 to 4 carbon atoms; or(c)

R.sub.fSO.sub.2N[(CH.sub.2CH.sub.2O).sub.qH][(CH.sub.2CH.sub.2O).sub.mH], where q is an integer from 1-6 and m is an integer from 3-6. R.sub.f is a fluoroalkyl group having 3 to 8 carbon atoms.(d)

A fluoroelastomer comprising a copolymer of fluoroolefin monomers selected from one or more of the group consisting of 2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene and 1-chloro-3,3,3-trifluoropropene, and ethylenically unsaturated co-monomers; wherein the fluoroelastomer has a glass transition temperature (Tg) of from about 60 C. to about 53 C. A process of making the fluoroelastomer.

The present invention is directed to partially fluorinated copolymers and the production thereof. More specifically, the copolymers, which are preferably produced by a solution polymerization process, preferably have at least three units, the first unit selected from 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene, the second unit having a polymerized monomer selected from the vinyl esters and vinyl ethers, and the third unit having a polymerized monomer derived from a hydroxyl group-containing vinyl ether. The resulting copolymer is environmentally friendly, has favorable molecular weight characteristics, and may be shipped economically in high concentration.