Multi-layered electret-containing filtration media

Abstract

Filter media for filtering gas streams (e.g., air) are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency, high oil repellency, low instantaneous resistance, and/or stable service life. One or more layers of the media may have a certain value of thickness over instantaneous resistance (and/or a ratio of thickness over instantaneous resistance between two layers). The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, respirator equipment), though the media may also be used in other applications.

Dependencies are inferred from the claim text.