The Best Material for Protective Medical Face Masks
Global shortages of medical face masks have led consumers to find creative ways to make their own, while some manufacturers of luxury goods have changed gear to help fight the shortage — by manufacturing medical supplies themselves.
But while a homemade face mask might be suitable for someone dashing off to the shops to stock up on supplies, medical-grade face masks and N95 respirators for health workers on the frontline need to meet exacting criteria.
The WHO estimates that 89 million medical masks are needed every month to address the crisis, and have called on the manufacturing industry to help increase the supply by 40%.
The Difference Between Surgical Masks and N95 Respirators
Disposable surgical masks, or face masks, are designed to protect the wearer from airborne particles and liquid. The loose-fitting device creates a physical barrier between the mouth and nose of the wearer. The edges of the mask do not form a seal around the nose and mouth.
An N95 respirator is a protective mask that fits closely on the face and forms a seal around the nose and mouth. Its purpose is the filtration of airborne particles. These surgical N95 respirators are class II devices regulated by the Food and Drug Administration (FDA). They are strictly a single-use product.
According to the FDA, N95 mask compliance is based on the following criteria:
- Differential pressure
- Particulate filtration efficiency
- Exhalation valve leakage
- Fluid resistance
Making Surgical Masks
Surgical face masks need to provide 85%-99% protection to prevent the spread of disease. They are made up of a multi-layered structure by covering one layer of textile with non-woven bonded fabric on both sides. Three or four layers are the norm. A fine inner mesh of plastic fibers acts as a filter. It is made from melt-blown fabric, which is what makes a mask breathable.
Melt-blown fabric is created through a process that melts down plastic and blows it out in strands. The same process is used to create spunbond fabric, which is also used in face masks worn by healthcare workers. The material most commonly used to make surgical masks is polypropylene, either 20 or 25 grams per square meter (gsm) in density. Masks can also be made of polystyrene, polycarbonate, polyethylene or polyester.
Manufacture includes several components such as the ear loops, the metal strip that allows you to bend the mask around the nose bridge, and the sterile packaging. Surgical masks need to be hypoallergenic, non-skin irritant and compliant with global standards.
The Best Materials for Surgical Masks
According to the Journal of Academia and Industrial Research (JAIR), the typical materials used to manufacture surgical face masks are polypropylene — 20 gsm made using spunbond technology and 25 gsm non-woven polypropylene made using melt-blown technology.
Polypropylene, polystyrene, polycarbonate, polyethylene and polyester are all suitable for manufacturing medical-grade face masks.
In cases were melt-blown fabric is scarce, a nanofilm coating filtration material can be used as a replacement. Sustainable alternatives to the plastic components can be created using 3D printing, such as eco-friendly 3D filament, which can be used instead of classic plastic filament.
Compliance Standards for N95 Respirators
N95 respirators are commonly used in construction and other industrial enterprises that expose wearers to dust and smoke. Some are only intended for use in a health care setting. One of the key differences is that N95 respirators need to filter out at least 95% of airborne particles and have to be thoroughly evaluated, tested, and approved before being used by medical professionals.
Like surgical masks, respirators also consist of multiple layers. The outer layer is constructed of a protective nonwoven fabric between 20-50 gsm density. This is followed by a pre-filtration layer 250 gsm thick and finally, a melt-blown electret nonwoven material.
The needled nonwoven fabric is produced through hot calendaring, where plastic fibers are thermally bonded together, helping the mask keep its shape. Completed respirators are sterilized before use.
Manufacturers That Have Stepped Up to Fill the Gap
The U.S. has passed new legislation to allow manufacturers like 3M, Honeywell and Moldex to produce 550 million masks for the healthcare sector. But as the crisis worsens, more and more companies across every sector have come forward to do what they can.
General Motors has tasked its seatbelt, fabric and vehicle interior experts to create 50,000 medical face masks a day to help those on the front line, while Fanatics, the company that manufactures the Nike uniforms for Major League Baseball, has temporarily converted its domestic factory to produce protective masks and gowns. The masks are made from the same polyester mesh fabric used to make player uniforms.
In Europe, Spanish furniture brand Nagami Design has rerouted its robotics department to concentrate on 3D-printing face shields for medical personnel. Clear plastic film is fastened to a second band attached to the visor, forming a protective shield that can be cleaned or replaced. The 3D-printed elements are made from recyclable polyethylene terephthalate glycol (PETG).
Reusable Facemasks on the Way
The Korea Advanced Institute of Science and Technology (KAIST) research team has developed a nano-filter that maintains excellent filtering efficiency even after being washed several times. The proprietary technology aligns nanofibers with a diameter of 100~500 nm in orthogonal or unidirectional directions. The team used an insulation block electrospinning process to manufacture orthogonal nanofibers by controlling the alignment of nanofibers. This process maximizes filtration efficiency.
On the other side of the globe, Yale researchers have discovered a way to recycle respirators for re-use for the same purpose. First, used masks in good shape are collected and then suspended from a rack. The racks of masks are then put through a re-processing procedure using hydrogen peroxide vapor. The sterilization process takes about five hours. With so many companies rising to the challenge and bringing their experience and innovation to the table, it just goes to show that anything can be achieved if we stand together.
For any manufacturer wanting to do its part to combat the global mask shortage, knowing the compliance standards is crucial. All face masks intended for use by medical personnel must undergo stringent testing and meet FDA standards in order to be suitable for use.
This article was provided by Open Packaging Network. For more articles visit opnplatform.com/blog