What were your next steps after you had identified the right material?
Häger: During our research, we contacted the Löseke Company in Hildesheim. The Company specializes in dust filtration bags and flexible packaging products made of filtration paper and manufactured makeshift masks amid the coronavirus crisis. This marked the starting point for our collaboration. Together we have enhanced the product over the past few weeks, aiming to also make fitting masks for children. We established that the filter materials have the right structure, i.e. great stability and resistance and feature the same so-called melt blown filtering layer as FFP masks. This filter layer works by using electric charging of particles which helps to trap aerosolized particles. That’s why this material is well suited to produce makeshift masks. So far, the Company has made ca. 100,000 masks a day using an ultrasonic spot welding technique, which is the same method used for conventional disposable face masks. It all goes hand in hand: the masks are produced and we continuously optimize them at the same time. Having said that, the market will soon be saturated thanks to imports, prompting the production to gradually decrease again in the near future. We will still finalize the prototype for our optimized mask concept to prepare for a possible second wave of the coronavirus. Our concept is subsequently ready and available should this be the case.
Who received the masks you have made thus far?
Häger: Initially, the masks were picked up by pharmacies, but are now also available via several online stores.
Can the masks be made in all sizes with the ultrasonic spot welding process?
Häger: The face mask body is simple, making it easy to produce the masks in different sizes. We created a pediatric probe device in our laboratory using 3D printing for the children’s mask template. We scanned the heads of multiple children to accurately reflect the relevant facial proportions. The mask test setup allowed us to study the impact of a reduction in size on respiratory resistance and leak rates with positive results. The masks have a simple shape but feature high-quality materials. They can be easily tailored to fit everyone.