Hollingsworth & Vose Company

Bruce Smith

David T Healey

Maxim Silin

Sudheer Jinka

Mark A Gallimore

Mohammad A Hassan

Greg Wagner Farell

Sudhakar Jaganathan

Nagendra Anantharamaiah

William S Freeman

Siqiang Zhu

Ingrid Rückert

Ingrid Staisch

Arash Sahbaee

Filter media, such as electret-containing filtration 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 over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. 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, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

Electret-containing filter media

Articles and methods relating to filter media are generally provided. In some embodiments, a filter media has an irregular surface structure. For instance, the filter media may comprise a plurality of peaks that are irregular in one or more ways. A ratio of a peak height standard deviation to an average peak height may be greater than or equal to 0.05, and/or a ratio of a peak spacing standard deviation to an average peak spacing may be greater than or equal to 0.08. In some embodiments, a filter media comprises a non-woven fiber web having a layer thickness of greater than 0.3 mm and/or a stiffness of less than or equal to 100 mg.

Filter media with irregular structure and/or reversibly stretchable layers

Filter media with irregular structure

Filter media including a waved filtration layer are described herein. The filtration layer may be held in a waved configuration by a support layer. In some cases, the filtration layer may have a combination of characteristics (e.g., mean flow pore size, basis weight, amongst others) that can lead to enhanced filtration performance (e.g., reduced air permeability decrease), in particular, in high humidity environments. The filter media may be used to form a variety of filter elements for use in various applications. In some embodiments, at least a surface of the filtration layer is hydrophilic.

Filter media including a waved filtration layer

Filter media including a waved filtration layer are described herein. The filtration layer may be held in a waved configuration by a support layer. In some cases, the filtration layer may have a combination of characteristics (e.g., mean flow pore size, basis weight, amongst others) that can lead to enhanced filtration performance (e.g., reduced air permeability decrease), in particular, in high humidity environments. The filter media may be used to form a variety of filter elements for use in various applications.

Filter media incorporating one or more filtration layers that include fibers including fiber portions orientated at a non-zero angle with respect to a surface of the filtration layer are provided. In some embodiments, at least a part of the fiber portions are positioned at an angle of at least 20 degrees (e.g., between 46 degrees and 90 degrees, or between 61 degrees and 90 degrees) with respect to a surface of the filtration layer or an outer or cover layer of the media. This orientation of fiber portions may result in an increased efficiency (e.g., average efficiency and/or initial efficiency) compared to similar filter media that do not include such oriented fiber portions.

Filter media including oriented fibers

Polymer compositions that may be used to form fibers for a fiber web are generally described. In some embodiments, certain properties of the polymer compositions (e.g., molecular weight distribution, melt flow index, melt elasticity, and/or melt toughness) may allow the formation of fiber webs having fine fibers and a relatively low amount of process defects. In some instances, these properties of the polymer composition may be achieved by combining two or more polymer components. Fiber webs formed using the polymer composition may have increased performance and/or better structural characteristics compared to fibers webs formed using a single polymer component.

Filter media including polymer compositions and blends

The fiber webs described herein may be incorporated into filter media and filter elements. The webs may exhibit a high permeability and stiffness, at a low thickness. The stiffness can be sufficient for the webs to be pleated to include sharp, well-defined peaks which can be maintained in a stable configuration during use.

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Copper Hill, VA, United States of America

Bruce Smith