摘要:
Fluorine-containing emulsifiers can be removed from fluoropolymer dispersions by adding to the dispersion a non ionic emulsifier, removing the fluorine-containing emulsifier by contact with an anion exchanger and separating the dispersion from the anion exchanger. The resulting dispersions can be concentrated and used for coating applications.
摘要:
Fluorine-containing emulsifiers can be removed from fluoropolymer dispersions by adding to the dispersion a nonionic emulsifier, removing the fluorine-containing emulsifier by contact with an anion exchanger and separating the dispersion from the anion exchanger. The resulting dispersions can be concentrated and used for coating applications.
摘要:
Non-free flowable, non-dusting molding powders with a bulk density of more than 450 g/l are obtained when a suspension polymer of tetrafluoroethylene with a content of 0.01 to 1% by weight of units of at least one perfluoro(alkyl-vinyl) ether is ground to a particle diameter of 10 to 50 &mgr;m and agglomerated in water.
摘要:
A fluoropolymer having a reduced amount of polar end groups. The fluoropolymer is produced by free radical polymerization of fluorinated monomers and the initiation of the polymerization is carried out in the presence of a chloride salt. Polar end groups include hydroxy groups and ionized or ionizable end groups. Examples of ionized or ionizable end groups include acid groups and salts thereof such as sulfonic acid and salts thereof, —CH2—OSO3H groups, sulfates and carbonyl containing end groups such as carboxylic and carboxylate groups. Due to the presence of chloride salt at the initiation of the free radical polymerization, CF2Cl end groups are formed instead of the polar end groups. As a result, a fluoropolymer is obtained that has improved processibility and heat resistance.
摘要:
A method of treating a fluorocarbon feedstock includes generating, in a high temperature zone, an electrical arc between at least one cathode and at least one anode, generating in the high temperature zone and by means of the electrical arc and a plasma gas, an upwardly burning thermal plasma having a tail flame, allowing a solid particulate fluorocarbon feedstock comprising at least on fluorocarbon compound to form a reactive thermal mixture with the thermal plasma tail flame, with the fluorocarbon compound dissociating into at least one fluorocarbon precursor or reactive species, and cooling the reactive thermal mixture to form, from the fluorocarbon precursor of reactive species, at least one more desirable fluorocarbon compound.
摘要:
A fluoropolymer suitable for the preparation of a fluoroelastomer. The fluoropolymer generally includes repeating units derived from the monomers tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene and optionally one or more repeating units from fluorinated monomers other than tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and chlorotrifluoroethylene.
摘要:
Fluorinated emulsifiers can be recovered from an aqueous phase containing small amounts of fluoropolymer particles by treating the aqueous phase with a small amount of a nonionic surface-active agent, bringing the aqueous phase adjusted in this way into contact with an anionic exchanger resin, and liberating the adsorbed emulsifier from the exchanger resin. The finely divided fluoropolymer can be precipitated quantitatively in the untreated aqueous phase or the eluate using flocculating agents.
摘要:
The present invention provides a method of recovering a fluorinated acid surfactant or salt thereof from adsorbent particles to which said fluorinated acid surfactant has been adsorbed. The method comprises mixing adsorbent particles having adsorbed fluorinated acid surfactant or salt thereof with an alcohol and optionally an acid. The mixture is generally heated to cause esterification of the fluorinated acid surfactant or salt thereof with the alcohol so as to form an ester derivative of the fluorinated acid surfactant, distilling the mixture to form a distillate comprising the ester derivative, separating the ester derivative from the distillate and optionally feeding the remainder of the distillate back into the mixture.
摘要:
Use of non-water-soluble organic fluorinated compounds, which are gaseous under the polymerization conditions and act as chain transfer agent in the gas phase, as explosion suppressors in the emulsion polymerization of tetrafluoroethylene.
摘要:
Provided is a process for making a copolymer of fluorinated olefin and hydrocarbon olefin selected from ethylene, propylene and mixtures thereof, the process comprising a substantially emulsifier free aqueous emulsion polymerization of said fluorinated olefin and said hydrocarbon olefin, optionally in the presence of fluoropolymer particles and/or fluorinated liquid in a form suitable to improve the copolymerization of fluorinated olefin and hydrocarbon olefin.