DOST-PTRI uses special coating to make ordinary masks more functional

By Rodolfo P. de Guzman, DOST-STII

With the ordinary face mask taking the limelight during this time of pandemic, it is very important to know what kind of face mask you would use to get the needed protection from the severe acute respiratory syndrome coronavirus 2 or SARS-CoV-2 that causes the deadly coronavirus disease or COVID-19. 

Taking up the challenge to find a better alternative, the Philippine Textile Research Institute of the Department of Science and Technology embarked immediately on developing a special face mask with added functionality and value. So, in truth, not all face masks are created equal.

N95 mask

As a general description, a face mask is a loose-fitting device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment.

If the face mask is worn properly, it can help block large-particle droplets, splashes, sprays or splatter that may contain viruses and microbes from reaching one’s mouth and nose. On the other hand, the face masks also help reduce exposure of one’s saliva and respiratory secretions, especially if one has cough, to others.

In general, face masks are effective in blocking splashes and large-particle droplets, a by design, they do not filter or block very small particles in the air that may be transmitted through coughs, sneezes or certain medical procedures. Face masks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the face mask and one’s face. Also, the face masks are not intended to be used more than once and should be disposed of properly.

The N95 respirator, on the other hand, is a respiratory protective equipment designed to achieve a very close facial fit and very efficient filtration of airborne particles. The edges are deliberately designed to seal portion around the nose and mouth. However, the Surgical N95 Respirators are more commonly used in healthcare settings like hospitals by healthcare workers as a personal protective equipment (PPE).

To ensure its protective characteristic, the N95 respirators are subjected to fluid resistance, bacterial filtration efficiency, particle filtration efficiency, breathability, and flammability tests.

It is called 'N95' because the respirator blocks at least 95% of very small (0.3 micron) test particles. When fitted properly, the filtration capabilities of N95 respirators exceed those of ordinary face masks. However, it must be noted that even a properly fitted N95 respirator does not completely eliminate the risks.

Surgical mask

Leveling up, the surgical mask is a kind of face mask made with non-woven fabric, that has better bacteria filtration and air permeability while remaining less slippery than woven cloth. The surgical mask material is commonly made of polypropylene with 20 or 25 grams per square meter (gsm) in density. Other masks can also be made of other materials: synthetic fibers like polystyrene, polycarbonate, polyethylene, or polyester.

This kind of mask is composed of multi-layered structure. The outer layer is made of nonwoven, water-repellent protective layer. The middle part is made of high-efficiency filter spray nonwoven. Lastly, the inner layer is made of finer fiber and skin friendly material.

Just like the N95 mask, the surgical masks are also tested for fluid resistance, bacterial filtration efficiency, particle filtration efficiency, breathability, and flammability. Similarly, the surgical mask should only be used once and discarded properly after every use.

Cloth mask

A cloth mask, from its name, is made of cloth or fabric and is mostly worn by people to protect themselves from air pollution. Its effectivity varies mainly with the kind of material used, the design and construction or how it was put together.

Specialized cloth masks can provide protection against particulate matter (PM) or microscopic particles that are present in the air.

REwear face mask, a cloth mask, will be tested for water-repellency, toxicity, fluid resistance, bacterial filtration efficiency, particle filtration efficiency, breathability, and flammability following the protocols shown in the figure below:

REwear Face Mask, the smarter alternative

DOST-PTRI, using the water-repellent textile finishing technology under its Smart Textiles R&D Program, has developed the REwear Face Mask that was made smarter than the ordinary cloth face mask. In fact, the REwear Face Mask is washable up to 50 times thus making it more economical in the long run. 

The finishing procedure involves application of silane compounds which are prepared into a nanosol or solution that is applied onto a natural-fiber blended textile such as cotton fabrics.

Many textile materials used for clothing, home textiles, and others may have water repellency or the ability to prevent water from penetrating. An example of this is the water-repellent fabric that can be used for a face mask.

Respiratory diseases, such as COVID-19 are transmitted through respiratory droplets over a short distance by coughing and through direct contact with a patient’s secretions.

As protection, cloth masks, especially those made of cotton, typically absorb liquid droplets, unless a finishing process is applied to it. By using water-repellent finishing, the liquid droplets will just slide down the REwear Face Mask.

Like a surgical mask made of multiple layers, the REwear face mask is constructed with a two-piece, three to four-layer mask. Fully detachable, the first piece (outer layer) is made of water repellent fabric and the second piece (inner layer) is made of absorbent fabric.

REwear Face Mask also underwent rigid testing for water-repellency, toxicity, fluid resistance, bacterial filtration efficiency, particle filtration efficiency, breathability, and flammability following the standard protocols.

REwear Face mask is an ideal protection for the following: people who care for patients with respiratory infection symptoms, people visiting clinics or hospitals, workers handling food, public transport operations staff/drivers, and people in crowded or poorly ventilated places.    (S&T Media Service/Source: Philippine Textile Research Institute)


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