Featherweight Filtration

Channeled fibers, with their increased capillarity, offer interesting possibilities for enhancing a
textile’s performance. Morrisville, N.C.-based Allasso Industries Inc.’s Winged Fiber™, developed
in collaboration with North Carolina State University’s (NCSU’s) Nonwovens Cooperative Research
Center, is exhibiting remarkable filtration and cosmetic delivery performance; and has potential
applications in tissue scaffolds, hemostatic bandages, battery separators, insulation and apparel.
The bicomponent fiber comprises a shaped core polymer and a sacrificial polymer that are coextruded
through a specially designed spinpack. The core features from eight to 32 deep channels between
uniform, straight-edged wings. The sheath polymer fills the channels during fiber formation and is
dissolved during finishing of the final product.


A typical 10- to 20-micron Winged Fiber is oblong. Its complex shape makes it much more
flexible than a solid fiber, said Allasso Industries President Walter Chappas, Ph.D. The fiber can
be tuned for a specific use by adjusting the width of the wings and the number of channels. It also
can be made in a circular configuration, or even a Y configuration with each leg having its own

The Winged Fiber is very lightweight and has the same total surface area as the equivalent
volume of 300-nanometer nanofibers. “There has been a lot of interest in developing filtration
materials using nanofibers, but there are problems,” Chappas said, noting high costs and fiber
compaction. “They filter beautifully, but the pressure drop goes way up, which prevents air or
water, as well as particles, from going through.” The Winged Fiber, in contrast, holds its
structure to allow air or liquid to flow through continuously. In filtration applications, dust or
other particles first fill the channels, allowing air or water to pass through the spaces between
the fibers for a longer time before the particles begin to fill those spaces. Therefore, pressure
drop is minimized, and the filter functions effectively for an extended time.

Nano Filtration Technologies LLC (NFT), Pittsburgh, manufactures media for high-efficiency
particulate air (HEPA) filters using an electrostatically charged polypropylene Winged Fiber
spunbond. The filters produced from this media, branded LEAF™ (Low Energy Air Filtration), are
claimed to have 250-percent greater loading capacity than traditional HEPA filters; and offer more
efficient air flow, lower energy consumption, a longer filter life and lower filter costs. The same
material is going into facemasks for industrial and medical uses.


HEPA filters made from NFT’s electrostatically charged polyropylene Winged Fiber LEAF™ filter
media are claimed to have 250-percent greater loading capacity than traditional HEPA filters, among
other benefits.

Korea-based La Care’s facial mask made using a nylon Winged Fiber spunbond is loaded with
moisturizing and rejuvenating essential oils and creams. The mask conforms to facial contours and
holds in place.


La Care’s cosmetic facial mask made using a nylon Winged Fiber™ spunbond is loaded with
essential moisturizing and rejuvenating oils and creams.

Researchers at the Joint Department of Biomedical Engineering, colocated at NCSU and the
University of North Carolina at Chapel Hill, are growing stem cells on a Winged Fiber substrate to
create bone tissue, and report promising results.

Allasso has demonstrated that continuous filaments of the fiber may be suitable for knitted
and woven apparel applications. Also in the works are staple fibers of various lengths to suit a
range of nonwoven and yarn spinning processes.

For more information about the Winged Fiber™, contact Walter Chappas +919-890-3803;
wchappas@allassoindustries.com; allassoindustries.com. Go online to
TextileWorld.com for archived Quality Fabric articles.

September/October 2012