From a supply-chain perspective, in 2020, the pandemic has challenged the availability of nonwoven materials that are employed for end-uses related to the COVID-19 response.

Typical N95 respirators and surgical masks are a multi-layer structure of two or more spunbond layers that provide mask shape and protect the inner meltblown filtration layer. The meltblown layer is electrostatically charged to allow for high efficiency and acceptable pressure drops.

In response to the COVID-19 crisis, NWI was able to modify microfibrillation technology to form a new class of facemask filter medium with an ultra-low pressure drop. This new structure does not require electrostatic corona charging .

There are no spunbond filters, as filtration media with similar properties and meltblown structures do not provide the same pressure drops. The material can be fine-tuned to produce facemask media targeting N95, N99, and N100 masks, as well as MERV 13 to 16 and HEPA filters.

NWI’s new approach uses a spunbond, hydroentangled nonwoven made from a PLA/PP bicomponent fiber that can be fibrillated by the waterjets during the process. The process uses novel jet strips that form a “quilted” structure. The degree of fibrillation can be controlled; partial fibrillation will result in a mix of fibers ~ (1-2 μm) and coarse fibers (15-25 μm), while full fibrillation results in a structure with fibers in the range of 1-2 μm.

Of note is that the process produces as much as 450 kg/m/hr. per beam. This is significantly higher that spunbond PP and far greater that the throughput on a meltblown system offering potentially lower costs and higher capacity.