Nonwoven Fabric PPE Guide

This informational guide has been created in response to forecasted shortages in the fabrics that are used in the production of personal protective equipment (PPE).

Nonwovens: the primary material component of PPE

According to the European Disposables and Nonwovens Association, nonwovens are innovative, high-tech, engineered fabrics made from fibers that are used in a wide range of consumer and industrial products.1

The expensive machinery that produces these products works by melting polypropylene pellets and injecting the liquid through tiny holes to make micron-sized threads. These threads congeal and are converted into a featherweight nonwoven fabric that can trap microscopic particles and droplets.2

Nonwovens are extensively used in the medical field, since their critical safety properties provide protection against infections and diseases. Nonwovens play a vital role in the fight against cross-contamination and the spread of infectious strains of bacteria and viruses.3

Spunbond/melt blown/spunbond (SMS), a primary nonwoven tri-laminate material used in the manufacture of PPE, consists of a middle layer of melt blown polypropylene fabric thermally sandwiched between two layers of spunbond polypropylene fabric. Each of these individually manufactured fabric layers’ properties contribute to the overall SMS end product. When combined, these two nonwoven fabrics provide water resistance as well as breathability and comfort.4

How is SMS fabric manufactured?

The spunbond process

The spunbond process converts melted polypropylene granules into nonwoven fiber. The fabric is produced by depositing extruded, spun filaments onto a collecting belt.5 This is followed by the bonding process, which imparts strength and integrity to the web by applying heated rolls to partially melt the polymer and fuse the fibers. Compared with melt blown fabrics, spunbond fabrics contain coarser fibers and a much greater tensile strength.6

The melt blown process

The one-step melt blown process, similar to the spunbond process, converts melted polypropylene granules into a low-diameter nonwoven fiber web. Extruded filaments are attenuated using high-velocity hot air streams; these impinge on the filaments as they emerge from extrusion nozzles, enabling much finer filaments to be obtained.7

The melt blown process is the only large-scale commercial process currently being used to produce melt-spun fibers that have diameters in the submicron range, without splitting or chemically dissolving away polymer. It is used to create nonwoven fabrics of various widths and thicknesses on large rolls.

Melt blown fabrics are composed of submicron filaments that have a large variation in diameter and therefore have superior filtration properties compared with spunbond fabrics.7 Figure 1 shows how the melt blown process is used to create fabric for medical masks.

Figure 1. Process and fabrics used to create surgical masks

How Medical Masks Are Made

 

Where is SMS fabric used?

Disposable nonwovens are extensively used in the medical field. Since products manufactured from these materials are single-use and are incinerated after use, the spread of contaminants is reduced due to minimized handling.3

Nonwovens are used in a wide variety of applications, including:

  • Single-use caps, gowns, face masks,
    scrub suits and shoe covers
  • Transdermal drug delivery
  • Drapes, wraps and packs
  • Underpads Sponges, dressings and wipes   
  • Procedure packs
  • Bed linen
  • Sterilization wraps
  • Contamination control
    gowns
  • Heat packs
  • Lab coats
  • Incubator mattresses
  • Isolation gowns
  • Cold/heat packs

How are protective materials and PPE rated?

Materials for surgical and isolation gowns, as well as surgical drapes, are rated based on their ability to act as barriers to liquids or liquid-borne pathogens. There are four levels of protection per the Association for the Advancement of Medical Instrumentation’s standards. For more detailed information, refer to the Vizient guide to isolation and surgical gown selection.

Respirators are classified by the National Institute for Occupational Safety and Health based on their ability to filter out microscopic particles as well as their oil resistance. For more detailed information, refer to the Vizient Covid-19 guide to face masks and filtering facepiece respirators.

Is there a shortage?

Nonwoven manufacturers around the globe are shifting capacity and investing in machinery in response to the COVID-19 pandemic. The global health crisis has caused an unprecedented demand for nonwoven products such as face masks and medical gowns.8

The global Organization for Economic Cooperation and Development noted that:9

  • There are bottlenecks in the face mask value chain, most notably with nonwoven fabrics manufactured with polypropylene
  • Current demand could be 10 times higher than world production capacity
  • Some countries have initiated restrictions on mask exports

Concerns for Vizient contracted suppliers

Our suppliers have expressed concerns over nonwoven supply chain challenges related to the global pandemic, such as price volatility and using up inventory reserves. One of our currently contracted suppliers has forecasted the likelihood of a critical shortage or outage of the middle melt blown SMS layer by the fourth quarter of 2020.

In addition, suppliers are apprehensive about the availability of most nonwoven polypropylene materials at scale, which is extremely limited. To address this challenge, one of our suppliers is working toward relocating some of its production to the North Americas; however, this move won’t take place until the first quarter of 2021.

Forging a path toward greater supply chain resilience

Although shortages of essential medications and products are not a new problem for hospitals, the COVID-19 pandemic has exacerbated supply chain disruptions.

In response, Vizient® has expanded its Novaplus® Enhanced Supply Program to include the PPE that providers need to protect themselves against COVID-19, as well as other viruses and workplace hazards.

References

  1. What are nonwovens? EDANA. Accessed August 4, 2020.
  2. Baldwin W. Where’s the fabric for masks and gowns? Forbes. March 26, 2020. Accessed August 5, 2020.
  3. Why use nonwovens in medical and healthcare? EDANA. Accessed August 4, 2020.
  4. An introduction into SMS material. Blue Thunder Technologies. May 23, 2019. Accessed August 4, 2020.
  5. Silva E. The spunbond process. Academia. 2010. Accessed August 4, 2020.
  6. Tensile strength. ScienceDirect. Accessed August 4, 2020.
  7. Melt blown process. ScienceDirect. Accessed August 4, 2020.
  8. McIntyre K. Nonwovens supply shift: Capacity investments target needs brought on by COVID-19. Nonwovens Industry. May 5, 2020. Accessed August 5, 2020.
  9. The face-mask global value chain in the COVID-19 outbreak: Evidence and policy lessons. OECD. May 4, 2020. Accessed August 4, 2020.

Visit the COVID-19 Resources for more information.