Abstract:
An aqueous fluoropolymer dispersion comprising an aqueous medium, fluoropolymer particles, and an amine oxide surfactant. Coagulated fluoropolymer resin is produced from the dispersion by adding an acidic reagent in sufficient amount to cause coagulation and separation of the coagulated fluoropolymer resin from the aqueous medium. Another particulate component such as particular polymer, filler, pigment, solid lubricant, etc., may be added to the dispersion and co-coagulated to form a mixture of coagulated fluoropolymer resin and particulate component.
Abstract:
The present invention provides a process for making a filled fluoropolymer bearing comprising providing an aqueous fluoropolymer dispersion comprising fluoropolymer particles and anionic polyelectrolyte dispersing agent in an amount sufficient for stabilization. The dispersion contains less than about 300 ppm fluorosurfactant based on the weight of the dispersion. The dispersion is coagulated to make a mush and a bearing filler is added to the dispersion prior to or after making the mush. The mush containing bearing filler is applied onto a bearing substrate to produce a coated substrate which is sintered and formed into a bearing.
Abstract:
The present invention provides a process for making a filled fluoropolymer bearing comprising providing an aqueous fluoropolymer dispersion comprising fluoropolymer particles and anionic polyelectrolyte dispersing agent in an amount sufficient for stabilization. The dispersion contains less than about 300 ppm fluorosurfactant based on the weight of the dispersion. The dispersion is coagulated to make a mush and a bearing filler is added to the dispersion prior to or after making the mush. The mush containing bearing filler is applied onto a bearing substrate to produce a coated substrate which is sintered and formed into a bearing.
Abstract:
The present invention provides a process for making a filled fluoropolymer bearing comprising providing an aqueous fluoropolymer dispersion comprising fluoropolymer particles and anionic polyelectrolyte dispersing agent in an amount sufficient for stabilization. The dispersion contains less than about 300 ppm fluorosurfactant based on the weight of the dispersion. The dispersion is coagulated to make a mush and a bearing filler is added to the dispersion prior to or after making the mush. The mush containing bearing filler is applied onto a bearing substrate to produce a coated substrate which is sintered and formed into a bearing.
Abstract:
A stabilized aqueous fluoropolymer dispersion comprising: about 30 to about 70 weight % non-melt-processible fluoropolymer particles having an SSG of less than about 2.225, said fluoropolymer particles comprising a core of high molecular weight polytetrafluoroethylene and a shell of lower molecular weight polytetrafluoroethylene or modified polytetrafluoroethylene; and about 2 to about 11 weight % of aliphatic alcohol ethoxylate nonionic surfactant based on the weight of said fluoropolymer, wherein said dispersion is essentially free of surfactants containing aromatic groups and contains less than 300 ppm of fluorosurfactant based on the weight of said dispersion.
Abstract:
A process for dispersion spinning non-melt-processible fluoropolymer fiber in which a mixture of an aqueous dispersion of non-melt-processible polytetrafluoroethylene or modified polytetrafluoroethylene fluoropolymer particles and an aqueous solution of matrix polymer is formed. The non melt-processible particles have an SSG of less than about 2.40. The aqueous dispersion contains an aliphatic alcohol ethoxylate nonionic surfactant having a 20% residuals temperature determined by thermogravimetric analysis (TGA) of less than about 290° C. and is essentially free of surfactants containing aromatic groups. The dispersion has a fluorinated surfactant content of less than about 300 ppm. The mixture is extruded into a coagulation bath containing a concentration of ions which coagulate the matrix polymer to form an intermediate fiber structure. The intermediate fiber structure is sintered to decompose the matrix polymer and coalesce. The present invention also provides a spinning composition useful for the dispersion spinning of non-melt-processible fluoropolymer fiber.
Abstract:
A process for reducing the fluorosurfactant content of an aqueous fluoropolymer dispersion by filling a container with fluoropolymer dispersion, inserting into the container a fabric pouch containing a fluorosurfactant sorbent so that the sorbent contacts the fluorosurfactant-containing aqueous fluoropolymer dispersion in the container and retains the fluorosurfactant to reduce fluorosurfactant content of said fluorosurfactant-containing aqueous fluoropolymer dispersion, and removing the fabric pouch from the container.
Abstract:
An aqueous fluoropolymer dispersion comprising an aqueous medium, fluoropolymer particles, and an amine oxide surfactant. Coagulated fluoropolymer resin is produced from the dispersion by adding an acidic reagent in sufficient amount to cause coagulation and separation of the coagulated fluoropolymer resin from the aqueous medium. Another particulate component such as particular polymer, filler, pigment, solid lubricant, etc., may be added to the dispersion and co-coagulated to form a mixture of coagulated fluoropolymer resin and particulate component.
Abstract:
Fluorinated carboxylic acid, used as a surfactant in fluoropolymerization in aqueous media, can be recovered by scrubbing from the exhaust gas of the dryer during polymer drying and, after concentration and treatment with alumina, directly reused in fluoropolymerization in aqueous media.
Abstract:
Aqueous dispersion polymerization of fluoromonomers is improved by using a combination of fluorosurfactants, one of which is a perfluoropolyether carboxylic acid or sulfonic acid or salt of either.