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DISPO
Disposable Face Masks
Progressive Replacement of Reusable Surgical Face Masks by Disposable ones since the 1960s
Disposable Face Masks: Clienti
SARS-CoV-2 is transmitted largely by the respiratory route (vide infra).
Disposable Face Masks: Testo
The best non-pharmaceutical interventions against disease spread via the respiratory route are broadly termed social or safe distancing measures, i.e., reducing close contact between individuals. Where safe distancing is not possible, personal protective equipment (PPE) is the accepted mode of self-protection. Masks and respirators are arguably the most important piece of PPE. They are a physical barrier to respiratory droplets that may enter through the nose and mouth and to the expulsion of muco-salivary droplets from infected individuals.
The history of the medical mask illuminates how this vulnerability was created. Covering the nose and mouth had been part of traditional sanitary practices against contagious diseases in early modern Europe. This protection was primarily about neutralising so-called miasma in the air through perfumes and spices held under a mask, such as the plague doctors’ bird-like masks. Face masks can be largely traced back historically to a more recent period when a new understanding of contagion based on germ theory was applied to surgery. In response to these findings, Mikulicz, an ethnic Polish surgeon, started to wear a face mask and in Paris, the surgeon Paul Berger also began wearing a mask in the operating room, both in 1897. These masks were described as "a piece of gauze tied by two strings to the cap and sweeping across the face so as to cover the nose and mouth and beard". The face mask stood for a strategy of infection control that focused on keeping all germs away, as opposed to killing them with chemicals.
It was mainly the use of the mask to cover the mouth and nose (and beard) during the Manchurian plague of 1910–11 and the influenza pandemic of 1918–19 that turned the face mask into a means of protecting medical workers and patients from infectious diseases outside of the operating room. During the 1918–19 influenza pandemic, wearing a mask became mandatory for police forces, medical workers, and even residents in some US cities. Yet in cities like San Francisco, the decline in deaths from influenza was partly attributed to the mandatory mask-wearing policies. At this point, the rationale for wearing masks moved beyond their original use in the operating theatre: they now also protected the wearer against infection.
Disposable Face Masks: Testo
Their main goal was to prevent respiratory droplets from being transmitted from and to the wearer, most masks were washable and the metal parts could be sterilised and “thus permit the use of the mask for a long time”.
Disposable Face Masks: Testo
Medical researchers tested and compared the filtering efficiency of reusable masks with experiments involving the culture of bacteria nebulised though masks or spread by infectious. They found that masks varied greatly in the extent to which they filtered bacteria. But when used properly, some masks were considered to offer protection from infection. Medical masks started to be replaced by disposable paper masks during the 1930s and were increasingly made of synthetic materials for single use in the 1960s. By the early 1960s, there were advertisements for new kinds of filtering masks made of non-woven synthetic fibres in nursing and surgery journals. These filtering masks were all disposable. Advertisements highlighted their performance, comfort, and convenience. These masks could be used only once because their synthetic fabric would deteriorate during sterilisation.
The substitution of reusable masks was part of the broader transformation in hospital care towards what a hospital administrator in 1969 called a “total disposable system” that included syringes, needles, trays, and surgical instruments. In part, disposability was supposed to reduce the risk of compromising the precarious state of sterility. However, another reason for switching to disposable masks was a desire to reduce labour costs, facilitate the management of supplies, and to respond to the increased demand for disposables that aggressive marketing campaigns had created among health-care workers.
Disposable Face Masks: Testo
Even though, there are three fabrics forming technology, nowadays, most of the surgical face masks are made up of non-woven with a view of disposing after use. Non-woven fabric forming technology is cheaper than other fabric forming technology like woven or knitted. Most of the surgical face mask manufacturers produce the surgical face mask using SMS (Spunbond Meltblown Spunbond) technology.
More effective surgical face masks which provides 85% or even 99% protection is required to prevent the spread of transmission diseases. The high degree of filtration efficiency is accomplished with a very fine filter layer of textile fibres covered on both sides with conventional non-woven bonded fabrics. The thickness of fibre is from <1 to 10 μm. Polypropylene, polystryrene, polycarbonate, polyethylene, polyester etc. are suitable for manufacturing surgical face masks. Apart from fibre selection, the filtration efficiency of surgical face masks depends on the method of manufacture, the structure of web, the cross-sectional shape of the fibre and its change (McCarthy, 2011). The suitable polymers are converted as a non-woven sheet using spunbond and melt-blown technology.
Disposable Face Masks: Testo
Advantages of non-woven fabrics over woven fabric in filtration are higher air permeability, higher bacterial filtration efficiency, no yarn slippage and low manufacturing cost (Kothari, 2008). The non-woven technology guarantees better barrier properties than cotton, polyester or even more advanced woven products. Besides, disposable non-wovens (surgical face masks, gowns, drape etc.) are sterilized, packaged, opened, used and then disposed.
Disposable Face Masks: Testo
The 3-ply surgical mask is commonly used in the COVID-19 pandemic. The 3-ply surgical mask is made up of 3 different layers of nonwoven fabric with each layer having a specific function. The outermost layer (typically blue) is waterproof and helps to repel fluids such as mucosalivary droplets. The middle piece is the filter, which prevents particles or pathogens above a certain size from penetrating in either direction. The innermost layer is made of absorbent materials to trap mucosalivary droplets from the user. This layer also absorbs the moisture from exhaled air, thus improving comfort. Together, these 3 layers effectively protect both the user and the surrounding people by limiting the penetration of particles and pathogens in both directions. Of all materials, polypropylene is the most common material used for a 3-ply surgical mask while other materials like polystyrene, polycarbonate, polyethylene, and polyester can also be used in masks. Coincidentally, polypropylene is the most common as it is relatively cheap and has low melt viscosity for easy processing.
Disposable Face Masks: Testo
Disposable Face Masks: Elenco
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