Abstract:
Aqueous fluoropolymer dispersions are described, along with coatings obtained with the dispersions, and methods of making coatings and dispersions.
Abstract:
Method of making fluoropolymers by emulsion polymerization of one or more fluorinated monomers in an aqueous phase in the presence of a fluorinated emulsifier, said method comprises adding a doping agent in a weight ratio with respect to the emulsifier of from about 1 : 2 to about 1 : 20, said doping agent has a melting point of equal or less than 30°C and a boiling point of at least about 100°C and is selected from the group consisting of fluorinated cyclic hydrocarbons, fluorinated polyoxyalkenes, fluorinated alkenes and fluorinated polyoxyalkenes.
Abstract:
The present invention provides a method of making a fluoropolymer comprising: (i) providing an aqueous dispersion of fluoropolymer particles by polymerizing one or more fluorinated olefins and optionally one or more fluorinated or non-fluorinated comonomers in an aqueous emulsion polymerization whereby the polymerization is initiated in the absence of a fluorinated surfactant and whereby no fluorinated surfactant is added during polymerization; (ii) recovering the fluoropolymer from the aqueous dispersion thereby obtaining said fluoropolymer and waste water; and (iii) contacting said waste water with an anion exchange resin; or alternatively to steps (ii) and (iii), contacting said aqueous dispersion with an anion exchange resin and subsequently separating said anion exchange resin from said aqueous dispersion.
Abstract:
The present invention provides an aqueous emulsion polymerization of fluorinated monomers including gaseous fluorinated monomers using a perfluoro ether surfactant as an emulsifier. The perfluoro ether surfactants correspond to formula (I) R f -O-CF 2 CF 2 -X (I) wherein R f represents a linear or branched perfluoroalkyl group having 1, 2, 3 or 4 carbon atoms and X represents a carboxylic acid group or salt thereof. In a further aspect, the invention also provides an aqueous fluoropolymer dispersion comprising the perfluoro ether surfactant and the use of such dispersion in the coating or impregnation of substrates.
Abstract:
The present invention provides an aqueous non-melt processible polytetrafluoroethylene dispersion comprising non-melt processible polytetrafluoroethylene particles in an amount between 30 and 70% by weight based on the total weight of the dispersion and one or more non-ionic surfactants and wherein at least a part of said non-melt processible polytetrafluoroethylene particles comprise polytetrafluoroethylene polymer chains having repeating units comprising ionic groups. The invention further provides a method for obtaining the dispersions.
Abstract:
The present invention provides a fluoropolymer that is melt-processible and thermoplastic and that has a melting point between 100 °C and 320 °C. The fluoropolymer is derived from (a) one or more gaseous fluorinated monomers, (b) one or more modifiers selected from (i) olefins having a bromine or iodine atom bonded to a carbon of the double bond of the olefin, (ii) olefins corresponding to formula (I): X a 2 C = CX a -R f -Br wherein each X a independently represents hydrogen, fluorine, bromine, chlorine or iodine, R f is a perfluoroalkylene group, typically having 1 to 8 carbon atoms, a perfluorooxyalkylene group or a perfluoropolyether group and (iii) mixtures thereof; and (c) optionally one or more comonomers selected from non-gaseous fluorinated monomers and non-fluorinated monomers. The resulting fluoropolymer has long chain branches. The invention further provides a method for making these polymers.
Abstract:
A composition includes an amorphous fluoropolymer having at least one of: a segment represented by formula I: -CF(R f )-(CX 2 ) n -(CX 2 CXR) m -O-R" f O k -(CXR'CX 2 ) p -(CX 2 ) q -CF(R' f )- (I); or a terminal segment represented by formula III: R f -CF(I)- (CX 2 ) n -(CX 2 CXR) m -O-R" f O k -(CXR'CX 2 ) p -(CX 2 ) q -CF(R' f )- (III), and fluoroplastic particles having a mean particle size of less than 500 nanometers. Each X is independently F, H, or Cl; R f and R' f are each independently F or a monovalent perfluoroalkyl having 1 to 3 carbon atoms; R is F or a partially fluorinated or perfluorinated alkyl having 1 to 3 carbon atoms; R" f is a divalent fluoroalkylene having 1 to 8 carbon atoms or a divalent fluorinated alkylene ether having 1 to 20 carbon atoms and at least one ether linkage; k is 0 or 1; and n, m, p, and q are each independently an integer from 0 to 5, with the proviso that when k is 0, n + m is at least 1 and p + q is at least 1. A method of making the composition is also provided.
Abstract:
The invention provides a fluorinated surfactant having formula [R f -(O) t -CHF-(CF 2 ) n -COO-] i X i+ , wherein R f represents a partially or fully fluorinated aliphatic group optionally interrupted with one or more oxygen atoms, t is 0 or 1 and n is 0 or 1, X i+ represents a cation having a valence i and i is 1, 2 or 3. The surfactant can be used in emulsion polymerization of fluoromonomers to prepare fluoropolymers.
Abstract:
The present invention relates to a method for making a fluoropolymer comprising an aqueous emulsion polymerization of one or more fluorinated monomers wherein said aqueous emulsion polymerization is carried out in the presence of an oligomer that comprises one or more ionic groups, has a partially fluorinated backbone, a number average molecular weight of not more than 2000 g/mol and that has a combination of repeating units different from that of the fluoropolymer that is being produced by the polymerization of said one or more fluorinated monomers. Since the polymerization of the one or more fluorinated monomers to produce the desired fluoropolymer is carried out in the presence of the oligomer, the resulting dispersion will contain the oligomer in addition to the fluoropolymer. Thus, in a further aspect, the invention relates to an aqueous dispersion of a fluoropolymer comprising the oligomer.
Abstract:
A tetrafluoroethene copolymer having a melting point of from about 240°C to 325°C, a melt flow index (MFI at 372°C and 5 kg load) of 0.5-80 grams / 10 minutes and having at least 70% by weight of units derived from tetrafluoroethene and further comprising units derived from at least one perfluorinated alkyl allyl ether (PAAE) comonomer corresponding to the general formula: CF 2 =CF-CF 2 -O-Rf (I) where Rf is a perfluorinated alkyl residue having from 1 to 10 carbon atoms and wherein the alkyl chain of the residue may be interrupted once or more than once by an oxygen atom and further, optionally, comprising units derived from perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE) and a combination thereof and wherein the content of units derived PAAEs and, optionally, PMVE, PEVE or a combination thereof, is at least 1.0 % by weight.