A novel emulsion polymerization process for the production of fluoroelastomers is disclosed wherein a partially fluorinated anionic surfactant of the formula F—(CF
2
CF
2
)
n
—CH
2
CH
2
SO
3
M, where n is an integer from 2 to 9, or mixtures thereof, and M is a cation having a valence of 1, is used as the dispersing agent.
In a process for the manufacture of fluoroelastomers, a coagulant is employed that is a water-soluble polymer having at least 2 quaternary onium centers. Specific examples of such coagulants include, but are not limited to poly(diallyldimethylammonium chloride), poly(epichlorohydrin-co-dimethyl amine), and poly(acrylamide-co-diallyldimethylammonium chloride).
In a process for the manufacture of fluoroelastomers, a water-soluble polymeric coagulant is employed that is an aqueous solution of polyethylene oxide homopolymer or copolymer having a viscosity average molecular weight of 500,000 or greater.
Antistatic compositions and thermally developable photographic materials containing the same
申请人:EASTMAN KODAK COMPANY
公开号:EP1348998A1
公开(公告)日:2003-10-01
Antistatic compositions include a fluorochemical that is a reaction product of Rf-CH2CH2-SO3H with an amine wherein Rf comprises 4 or more fully fluorinated carbon atoms. These antistatic compositions can be formulated in organic solvent-based conductive coating compositions, with or without hydrophobic binders, that can be used to form conductive layers in thermally developable materials including thermographic and photothermographic materials.
Compositions of specialty fluoroelastomers containing copolymerized units of tetrafluoroethylene, propylene, optionally vinylidene fluoride, and a cure site monomer selected from the group consisting of i) trifluoroethylene, ii) 3,3,3-trifluoropropene-1, iii) 1,2,3,3,3-pentafluoropropylene, iv) 1,1,3,3,3-pentafluoropropylene, and v) 2,3,3,3-tetrafluoropropene are readily curable with polyhydroxy curing systems. The resulting cured articles have a combination of excellent resistance to alkaline fluids, superior tensile properties and compression set resistance.