The new filter is made by crossing fine nanofiber at right angles or by tightly aligning fibers in a row, with smaller and equally spaced air holes. (image: KAIST)
SEOUL, March 17 (Korea Bizwire) — A mask that can be reused and still maintain its filtering function after being washed more than 20 times has been developed.
Much attention is paid on whether the new mask filter can solve the problem mask shortages amid the growing coronavirus outbreak.
A team of researchers from the Korea Advanced Institute of Science and Technology (KAIST) said Monday they have developed a nanofiber filter that maintains filter efficiency even after washing with an “Insulated Block Electrospinning” method that intersects or aligns nanofiber at right angles in a cross-shaped pattern.
The existing melt blown filters are non-woven, randomly intertwined fibers, with varying pore sizes, and require multiple filters to be overlaid to block even small particles.
In addition, static electricity formed on the surface of the fiber disappears when it touches moisture, and after a certain period of time, the efficiency of the filter decreases drastically when it is washed or worn.
The new filter is made by crossing fine nanofiber at right angles or by tightly aligning fibers in a row, with smaller and equally spaced air holes.
This allows the same blocking efficiency with less thickness than conventional filters. The masks are airy and make it easy to breathe as well.
Even after washing with ethanol or soap several times, the particle blocking function was maintained.
Although the team hand-washed the filter more than 20 times with soap and immersed it in an ethanol solution for more than three hours, the structure of the filter remained unchanged and the performance remained at 94 percent compared to the initial performance.
Furthermore, the mask was still able to block particles better than a KF80 mask even after it was folded and bent more than 4,000 times.
The team also developed cotton mask that can make use of the reusable filters.
When considering the masks and filters can be washed with ethanol spray or soap and reused 10 to 20 times, people can live a month, or even longer, with two to three filters.
A KAIST startup company established in February of last year can produce a filter sheet 35 centimeters wide and 7 meters long in an hour. Using this method, the company can manufacture an average of 1,500 mask filters per day.
Professor Kim Il-doo of KAIST, who led the research team, said, “The mask can be reused with ethanol disinfection or light hand washing, which will solve the environmental problem caused by the loss of masks and the disposal of masks.”
“We plan to expand the facilities for mass production by using related procedures such as approval from the Ministry of Food and Drug Safety,” he added.
D. M. Park (dmpark@koreabizwire.com)
