What secrets are hidden in reusable masks

- May 07, 2020-

Will there be reusable masks?

At present, the most common medical surgical masks on the market are made of two layers of non-woven fabric and one layer of melt-blown fabric. The melt-blown fabric acts as a filter layer and is sandwiched between two layers of non-woven fabric. It is this layer of meltblown cloth that plays the role of filtering viruses.

Why are these masks disposable? The reason is also on this layer of meltblown cloth. The melt-blown cloth exerts its filtering effect by electrostatic adsorption. Once the adsorption is almost completed, the mask has no protective effect. Moreover, melt-blown materials will age during use and cannot be used for long periods of time.

Since the problem is with the meltblown cloth, then the idea of the meltblown cloth has to be hit. There are two ways: one is to make it detachable, and the other is to find a way to keep it filtering for a long time, that is, to extend the service life.

The good news is that some manufacturers have already done so.

Mask + inner core

The first method is simple and easy. The mask is originally a sandwich design. With a slight modification, a mask with a removable filter layer can be produced. Now, some manufacturers are producing such masks with inner cores. A mask with N inner cores can be used for N days.

New materials help new products

Is the second option feasible? As mentioned earlier, the filtering effect of the meltblown cloth relies on electrostatic adsorption, which is destined to have limited single use time. This is also the reason why medical masks cannot be washed with water, because washing will neutralize static electricity and cause loss of filtering effect. It seems that to solve this problem fundamentally, I am afraid that only the meltblown material can be replaced.

A reusable mask developed by a Shanghai children's clothing company in cooperation with a new material technology company has adopted this idea. This new mask replaces the meltblown fabric with a nanofiber microporous film. The filtration mechanism of this nanomaterial is no longer electrostatic adsorption, but direct filtration-yes, it is the kind of filtration achieved by pores. Theoretically, as long as the pore design is reasonable, it can maintain the filtration effect for a long time while satisfying breathability, and the mask can also withstand the "test" of water washing after use, without affecting the filtration performance.