PRODUCTION METHOD OF ELECTRET FILTER MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a production method of an electret filter medium of a porous dielectric sheet which is highly and sufficiently turned into an electret to its interior. SOLUTION: An aqueous solution containing at least one organic or inorganic compound having an index (pKa) of acid dissociation of not less than 3.0 is jetted to the porous dielectric sheet with a pressure sufficient for the solution to pass through the sheet so as to turn the sheet into the electret to its interior sufficiently, and then the sheet is dried to produce the electret filter medium. COPYRIGHT: (C)2004,JPO