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US 5,230,800 AGranted
Scrim inserted electrostatic fibrous filter web
AssigneeMinnesota Mining and Manufacturing Company
InventorDavid L. Nelson
Life of this patent
Estimating the term…
Abstract
Provided is a nonwoven web of electrically charged fibers needle-punched to a scrim support. This web provides a filter medium having increased uniformity in pressure-drop, basis weight and filtration performance.
Claims12
A method for forming an electret nonwoven filter web comprising the steps of
- a) providing electrostatically charged, dielectric, fibrillated discontinuous fibers formed by fibrillating an electrostatically charged film,
- b) forming the electrostatically charged discontinuous fibers into at least one nonwoven filter web,
- c) joining the at least one filter web to a reinforcement scrim, and
- d) consolidating the at least one filter web by needle punching the at least one filter web and reinforcement scrim to form a filter web with substantially uniform basis weight and filter performance properties across the web.
1 more element
A uniform electret nonwoven filter comprising at least one nonwoven filter web of electrostatically charged dielectric fibrillated fibers formed by fibrillation of an electrostatically charged film joined to a reinforcement scrim by needle punching.
Dependencies are inferred from the claim text.