Lately, N95 masks seem to be the only word we hear about on the news or read online. The shortages of this particular face mask in the United States have made it very difficult for healthcare centers to obtain them. In this article, we’ll analyze the materials used to make them, and how it influences the scarcity of the product.
What is an N95 mask?
In the USA, the National Institute for Occupational Safety and Health (NIOSH) is an institute that is responsible for regulating respirators as part of their goal to prevent work-related injuries or illnesses. For this, they have established a rating classification for air filtration, where they classify and name respirators based on certain characteristics.
The names given to respirators take into consideration mainly two characteristics:
- Resistance to oil: indicated by the letters N, R, and P, for non-resistant, resistant, and oi-proof respectively.
- Percentage of minimum particulate filtration efficacy: which can be either 95, 99, or 100%.
According to this classification, N95 respirators are any respirator that isn’t resistant to oil, and can filter out at least 95% of all airborne particles. This means they’re effective for protection against non-oil based particles, like dust, smoke, or the flu virus. This is why they’re considered to be the best face mask for virus protection, because it has more antiviral properties than reusable cloth masks, or surgical and medical face masks. Anyone who uses an N95 mask is getting the best virus protection available at the moment.
KN95 masks, which are regulated under the Chinese standards, are considered to be their equivalent, and in many cases can substitute N95 masks. N95 respirators can also be paired with face shields to increase the protection they offer.
What kinds of materials are used to make N95 masks?
The materials used to produce N95 masks can vary, but the most used one is polypropylene. This is a polymer that is thermoplastic, meaning that it can be molded when high temperatures are applied to it and will solidify in that position after temperatures have dropped.
This is a propylene polymer, and this means that it’s made of lots of propylene molecules. Propylene is a hydrocarbon obtained from fossil molecules, and it’s a very popular and important raw material used in the textile industry. For this reason, propylene is the second most used plastic worldwide.
With polypropylene, factories produce a fabric commonly known as “non-woven fabric” or “melt-blown material”. This means that the fabric doesn’t need weaving, and it’s widely used in textiles for its lightweight nature and high resistance to environmental conditions.
The material is also known as melt-blown fabric because the process to obtain it is called melt-blown extrusion. This can be either a thermic, mechanical, or chemical process that binds the material together, resulting in a web-like fabric with lots of properties that make it useful for N95 masks and many other products as well.
Other materials used in the manufacturing process of N95 masks include metals to make smaller details, like the staples or the nose clip. We can also find woven fabrics and elastic to make up the headbands or ear loops.
As we explained, for a respirator to be called an N95 mask, it has to be certified by NIOSH after meeting the two characteristics established by them. Since this classification is based on the performance of the mask and doesn’t take into account the materials used, N95 masks don’t have to be made of melt-blown material necessarily. They could be made of virtually anything, and as long as they meet the criteria and are approved by NIOSH, they can be called an N95 respirator.
This non-woven material makes up the filter media of the N95 mask, which has a series of very small pores that can trap small particles, thus preventing the user from inhaling them. To be certified as N95, the filter needs to trap airborne particles that have a diameter of 0.3 micrometers, so holes would have to be smaller than that to trap them.
However, N95 masks need to meet other requirements as well, including breathability. If the filter is made with pores that are too small, it could prevent the user from breathing comfortably, so pores can’t be that small. To meet both requirements, other filtration techniques are added to the filter media so that the pores can be big enough to let the user breathe correctly.
One of the most used mechanisms is electrostatic filtration. Polypropylene doesn’t have an electrostatic charge naturally, so manufacturers add the charges to the material to enhance its filtration properties. The principle for this method is that the charges will attract particles with the opposite charge, both large and small.
But, even though this non-woven material offers a lot of good properties to N95 masks, it isn’t very durable. N95 masks need to be discarded after being used for 8 to 12 hours. After that, it starts to lose all the filtration properties, making it not as effective. This happens because the materials in the mask start to degrade and also lose their electrostatic charges.
This is why reusing N95 masks doesn’t offer as much protection as using a new one. The Centers for Disease Control and Prevention has a series of guidelines and recommendations for healthcare workers to prolong the lifespan of these masks during the COVID-19 pandemic as these respirators have become more scarce over time.
The scarcity of N95 masks can be attributed to multiple factors, but a main contributor to the shortages has been the scarcity of the melt-blown material itself. Manufacturers of this fabric have increased their production, but the demands seem to surpass their capacity.
While melt-blown material is the most important part of the respirator, it’s also the hardest to produce. New lines of production can’t be made so easily as the machines used for its manufacturing are only made by six companies in the world. These machines are also expensive, large, and hard to operate, making buying one of them a 12-month process overall.
If you’re looking to buy N95 respirators for sale in bulk or wholesale, including 3M N95 masks in the models 3M 8210 and 3M 8511, always make sure to use legitimate and reliable sources. Staying safe is the priority today.