MC² Market & Competitive ConvergencePatented InventionPatent issued by the US Patent and Trademark Office United States Patent: 5,874,373 Pryne and West, Feb. 23, 1999 Enhanced electret needled filtration media and composites Abstract An enhanced filtering media composite formed of a first electret media layer attached uniformly onto a second nonwoven fibrous media layer by a special needling construction and procedure, so as to provide a needled media composite having increased mechanical strength and particle retention capacity. The first media electret layer is composed of about 50% by weight mixture of polypropylene and modacrylic fibers, and the second media layer is composed of 80% 3 denier by 3 inch polyester staple and 1.5 denier by 1.5 inch polyester staple fibers, the fibers of one layer being selectively needled into the other layer using controlled needling density penetration, depth and repetitions to provide a composite having improved mechanical strength and filtration performance. Inventors: Pryne, Scott H. (Newburgh, NY); West, Ross D. (Newburgh,
NY).
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