Spectra and Kevlar – Not a Fashion Statement

July 16, 2020 Stan

Over the years, many improvements have been made in military and police garments to increase safety and create bullet proof body armor that is both comfortable and protective. However, in the past, being safe has meant a certain amount of bulk and discomfort, as well as added weight and mass for soldiers and officers facing combat on the battle fields and in urban wars. The use of Kevlar, a registered trademark of DuPont, has made body armor lighter and easier to work with, but flexibility has still been a problem. Today, there is a new substance in use called Spectra, a composite material that is stronger, lighter, and more flexible than Kevlar, which is changing the face of bullet proof wear for our troops and police forces. What are the major differences between Kevlar and Spectra, and what are the big advantages of the latter?

Let’s first examine the structure of each of the two materials. Kevlar is a high strength, high performance fiber that, despite its many years of use in bullet proof clothing, is still not entirely understood. The best description of how it is believed to function is that the molecules form into sheets that then stack themselves around the center of a fiber like spokes. The idea behind using this as a bullet proof material was to stack several layers of the material together in a weave pattern. The weaving would then “catch” the bullet by allowing the fibers to break apart layer by layer and absorb the velocity, slowing the bullet to a stop as it also dulled and flattened from striking the material. However, this was mostly effective when bullets were slower and had less total velocity, making them easier to stop. Now, our troops and law enforcement officials face much more technically advanced weaponry with bullets flying at higher speeds and constructed from harder metals. This means that Kevlar vests are stretched to capacity and sometimes even penetrated completely by these forceful weapons. The only answer with this material is to thicken the layers of weave, which make the material even bulkier, heavier, and less flexible.

Spectra is a completely different technology. The material is about 40% lighter than Kevlar, making it more comfortable from the start. On top of that, it is not a woven structure, meaning that several layers are not necessary, further reducing weight and bulk. At the same time, Spectra is ten times stronger than steel. So, what is this substance actually made out of that makes it compete with Superman for the title of strongest bullet proof material? The definition states that Spectra is a “thin, flexible ballistic composite made from layers of unidirectional fibers held in place by flexible resins”. These layers are then sealed between two thin sheets of polyethylene film (think plastic wrap on your leftovers). Therefore, all materials used are light weight and extremely flexible, making movement and wearability more realistic for users. At the same time, it disperses the energy of a bullet much faster across a wider area and with greater efficiency, providing much more reliable protection against the higher velocity bullets used in combat and street crimes today. So far in testing, the performance of Spectra seems to be unaffected by chemicals and moisture.

What you may not realize is that these materials are also used in everyday materials that civilians work with constantly. For instance, many tires today employ Kevlar in their structural makeup to add a modicum of indestructibility to the material. Spectra has been used to a lesser degree in items such as “carry-all” shopping bags.

While Spectra is a fairly new material, and most ballistic body armor still employs the use of Kevlar, both substances are important to the safety of officers of law enforcement and soldiers. As time goes on, the classic use of Kevlar will most likely be replaced by the lighter weight Spectra material that is also stronger, especially as the technology improves and allows for the creation of full body armor. The important thing is that both materials are used properly as necessary so that the safety of troops and police forces are not compromised, and if that means sticking with proven materials, then that should be the solution. Kevlar has worked for over twenty years in all forms of combat and can be counted on to do the same in the future with minor changes to the structure of tactical vests.