Patent ID: 8709139
Filing Date: 2014-04-29
Classification: B01D,B32B,D04H

Abstract:
1. A ply for use in a HEPA filter element, comprising: a first carrier layer, said first carrier layer comprising first polypropylene fibers having a core/mantle structure, said mantle comprising metallocene catalyzed polypropylene, said core comprising pure polypropylene wherein melting of said mantle fibers occurs without the core structure being impaired, said first polypropylene fibers being electrostatically charged for stabilization; and a second precipitation layer, said second precipitation layer comprising second polypropylene fibers, where said second polypropylene fibers are at least in part electrostatically charged and wherein said precipitation layer includes nanofibers selected from polyamide, polyacrylonitrile, polycarbonate or polypropylene; wherein: