Abstract: The present invention provides a polymeric, particularly aramid, fiber filtration sheet having a relatively small pore size and high pore uniformity. The present inventive aramid fiber filtration sheet preferably has a titer reduction against bacteria such as Pseudomonas diminuta. The present invention also provides a method of preparing reduced-diameter aramid fibers, as well as a method of preparing an aramid fiber filtration sheet from such reduced-diameter aramid fibers. The present invention further provides a method of treating a fluid by passing a fluid through the present inventive aramid fiber filtration sheet, as well as a filter element incorporating the present inventive aramid fiber filtration sheet.

Abstract: The present invention provides a polymeric, particularly aramid, fiber filtration sheet having a relatively small pore size and high pore uniformity. The present inventive aramid fiber filtration sheet preferably has a titer reduction against bacteria such as Pseudomonas diminuta. The present invention also provides a method of preparing reduced-diameter aramid fibers, as well as a method of preparing an aramid fiber filtration sheet from such reduced-diameter aramid fibers. The present invention further provides a method of treating a fluid by passing a fluid through the present inventive aramid fiber filtration sheet, as well as a filter element incorporating the present inventive aramid fiber filtration sheet.

Abstract: Filter media comprised of charge modified, resin coated inorganic microfibers are prepared by mixing inorganic microfibers with an aqueous solution of a water soluble, noncolloidal cationic thermosetting binder resin to form a dispersion, following which a precipitating agent is added to precipitate the binder resin and coat the microfibers. The coated microfibers may be used in the dispersed or suspended form as a filter aid. Preferably they are formed into a filter sheet which is then dried and cured to form a filter sheet of narrowly distributed pore size, pore sizes as small as one-half micron, and having a positive zeta potential in alkaline media. Glass is the preferred microfiber and polyamine-epichlorohydrins the preferred resins. By providing the normally negative zeta potential microfibers with a positive zeta potential the binder resins used to coat the microfibers substantially enhance particulate removal capabilities of the microfiber filter sheet.

Abstract: A process for making a porous, fibrous structure coated with a fluorocarbon polymer comprising (1) preparing an aqueous slurry of inorganic fibers and fluorocarbon polymer; (2) precipitating the fluorocarbon polymer onto the inorganic fibers by lowering the pH of the slurry to an acidic value and adding a cationic flocculant; (e) forming a porous, fibrous structure from the resulting slurry; and (4) drying and heat treating the resulting structure. The porous, fibrous structure comprises inorganic fibers the surfaces of which are coated with a precipitated fluorocarbon polymer with the fibers secured to one another at cross-over points by the fluorocarbon polymer thereby providing structural integrity.

Abstract: Filter media comprised of charge modified, resin coated inorganic microfibers are prepared by mixing inorganic microfibers with an aqueous solution of a water soluble, noncolloidal cationic thermosetting binder resin to form a dispersion, following which a precipitating agent is added to precipitate the binder resin and coat the microfibers. The coated microfibers may be used in the dispersed or suspended form as a filter aid. Preferably they are formed into a filter sheet which is then dried and cured to form a filter sheet of narrowly distributed pore size, pore sizes as small as one-half micron, and having a positive zeta potential in alkaline media. Glass is the preferred microfiber and polyamine-epichlorohydrins the preferred resins. By providing the normally negative zeta potential microfibers with a positive zeta potential the binder resins used to coat the microfibers substantially enhance particulate removal capabilities of the microfiber filter sheet.