Abstract:
A vulcanizable fluoroelastomer composition from which a vulcanizate reduced in compression set can be produced in a short time and which is excellent in molding stability and suitability for kneading. It comprises a fluoroelastomer having C-H bonds in the polymer chain, a vulcanizing agent, and a vulcanization aid, wherein the optimum vulcanization time for the composition, T90 (min), and the compression set of the vulcanizate, CS (%), satisfy the following relationships (I) and (II): Relationship (I): CS x MW, provided that 50,000
Abstract:
A method of producing a fluoroelastomer reduced in the content of metallic ingredients; and a molded article comprising a fluoroelastomer sufficiently reduced in the content of metallic ingredients. The method comprises producing a fluoroelastomer without using a metal oxide through fluoromonomer polymerization, coagulation, and drying, wherein at least one of the starting materials excluding gaseous monomers contains substantially no metallic ingredients. The fluoroelastomer obtained by this method has a metal content of 50 ppm or lower.
Abstract:
A process for producing a fluoroelastomer composed of vinylidene fluoride units and other fluoromonomer units copolymerizable therewith by suspension polymerization, which comprises: (1) dispersing the above monomers in 100 parts by weight of an aqueous medium containing 0.001-3 parts by weight of a suspension stabilizer, (2) using a polymerization initiator solution prepared by diluting 0.001-5 parts by weight of an oil-soluble organic peroxide in a concentration of 0.1-75 % by weight with a halogen-fee water-soluble hydrocarbon solvent represented by the general formula R-OH, R2-COO-R1 or R1-CO-R3 (wherein R1 and R3 represent each methyl or tert-butyl, and R2 represents hydrogen, methyl or tert-butyl), and (3) conducting the suspension polymerization at 45-70 DEG C. The process provides a fluoroelastomer which has excellent resistances to heat, oil and chemical, a reduced compression set and a good releasability, and little stains a mold. Further it can dispense with the use of an ozonosphere-depleting chlorofluorocarbon solvent and facilitates the recovery of the monomers and solvent.
Abstract:
Curable fluoropolymer containing repeating units derived from VDF and TFE and at least one other fluorinated comonomer and further containing -CF 2 CH 2 I end groups and branching sites derived from one or more perfluorinated bisolefinic ether(s) used as modifier(s), wherein the one or more perfluorinated bisolefinic ether(s) used as modifier(s) correspond to the general formula: CF 2= CF-(CF 2 ) n -O-(R 1 )-O-(CF 2 ) m CF=CF 2 wherein n and m are independent from each other either 1 or 0 and wherein R 1 represents a perfluorinated linear or branched, cyclic or acyclic aliphatic or aromatic hydrocarbon residue that may be interrupted by one or more oxygen atoms and comprises up to 30 carbon atoms. Further provided are methods of making the curable fluoropolymers and for making an article containing the curable polymers.
Abstract:
L'invention concerne une composition comprenant : - au moins un terpolymère fluoré électroactif, et - au moins un deuxième polymère compatible avec le terpolymère fluoré électroactif, et présentant une température de transition vitreuse inférieure à celle du terpolymère fluoré électroactif. L'invention concerne également un procédé de fabrication de cette composition, ainsi qu'un dispositif tel qu'un actionneur comprenant un substrat et un film de la composition ci-dessus.
Abstract:
L'invention concerne un procédé de préparation d'un polymère à partir de monomères comprenant le fluorure de vinylidène, le trifluoroéthylène et un tiers monomère, le procédé comprenant successivement: l'injection dans un réacteur de la totalité des monomères mis à réagir; l'initiation d'une polymérisation des monomères; une étape (a) de poursuite de la polymérisation des monomères, au cours de laquelle on compense une chute de pression dans le réacteur.