Abstract: Electret webs include a thermoplastic resin and a charge-enhancing additive. The charge-enhancing additive is a substituted-benzoic acid or a substituted-benzoate salt. The benzoic acid and benzoate salts are substituted by a hydroxyl or amino group at the ortho position or 1 position of the benzene ring. The benzene ring may contain additional substituent groups. The substituted-benzoate salt may have a monovalent, divalent, or trivalent metal counteraction.

Abstract: A filter element that has rows of folded pleats and includes a nonwoven filtration web that contains thermoplastic fibers, a majority of which fibers are aligned at 90°±20° with respect to the row direction. The filter elements can be made by forming rows of pleats in such a nonwoven web and cutting the web to a desired size and shape. The filter elements can provide improved mechanical and filtration properties.