Charge-modified microfiber filter sheets

US4523995A · kind A · utility

Assignee

• Pall Corporation · US

Inventors

• David B. Pall · Glen Cove, US
• Peter J. Degen · Woodbury, US
• Irving B. Joffee · Huntington, US
• Warren M. Foss · Glen Cove, US
• Thomas C. Gsell · Dillingen/Saar, DE

Key dates

• Filing date: Oct 19, 1981
• Grant date: Jun 18, 1985
• Expiry date: Oct 19, 2001

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D2239/0471
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

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.