Today we are talking about pistol rated armor, of which Kevlar is the most well known as the classic “Bulletproof vest.” Kevlar is a Para-aramid synthetic material renowned for its durability, tensile strength, and resistance to impact, which makes it a top choice for bullet resistant vests. However, while Kevlar and Para-aramid might seem synonymous at a glance, they have different attributes that should be considered when choosing between them.

NIJ Testing

The National Institute of Justice (NIJ) is the authority on body armor in the United States. They provide a universal standard to ensure the reliability and performance of personal protective gear. The NIJ performs rigorous testing on various types of body armor, including those made from Kevlar and Para-aramid.

In the context of Kevlar and Para-aramid, both materials have been extensively tested by the NIJ and have been approved to protect from various levels of threats. Typically, Kevlar and Para-aramid are used in body armor designed to resist handgun rounds, such as those found in NIJ Level II and IIIA vests.

However, the specific protection offered can vary based on the thickness of the material, the number of layers used, and the presence of additional ballistic-resistant materials.

What Is Para-Aramid Body Armor?

Para-aramid body armor is a type of protective vest constructed from para-aramid fibers, which includes materials like Kevlar and Twaron. Para-aramid body armor is known for its high tensile strength, making it highly effective in stopping bullets and protecting the wearer from shrapnel, stabs, and other forms of impact energy.

Bullet-Resistant Body Armor Insert - Tacticon Armament
Bullet-Resistant Body Armor Insert

The structure of the para-aramid fibers allows them to distribute the force of the impact across a larger area, reducing the potential for injury. Typically, para-aramid soft body armor is effective in stopping bullets from most handguns and shotgun shells, and when combined with other materials or specialized design elements, can also protect against certain rifle rounds.

Are Kevlar and Para-aramid the Same?

While Kevlar and Para-aramid share several similarities, they are not the same. Both are high-strength synthetic fibers that boast excellent heat resistance and strength-to-weight ratios. Their resilient nature makes them perfect for use in protective gear, particularly body armor.

Kevlar is a trademark of the chemical giant DuPont, and is perhaps the best-known type of Para-aramid. It’s known for its impressive tensile strength – five times stronger than steel on an equal weight basis – and is used widely in body armor, aerospace, and even musical instruments.

Para-aramid, on the other hand, is a category of synthetic fibers that includes Kevlar. While Kevlar is a type of Para-aramid, there are other types of Para-aramid fibers too, such as Twaron and Heracron. Each type of Para-aramid has a unique set of characteristics and applications.

In the realm of body armor, both Kevlar and other types of Para-aramid are utilized due to their excellent ability to absorb and dissipate energy, crucial when stopping a bullet or reducing the impact of a blow. However, the choice between Kevlar and other Para-aramids will depend on the specific needs and considerations of the user, such as the level of protection required, the nature of the threats they face, and their budget.

Shot Kevlar Body Armor Insert - Tacticon Armament
Shot Kevlar Body Armor Insert

Para-Aramid Body Armor Plate Structure

Para-aramid body armor often utilizes a unique structural design that employs both a polymer film resin matrix layer and unidirectional (UD) technology.

Polymer Film Resin Matrix Layer

This layer in the body armor is primarily composed of a polymer resin, which is bonded with para-aramid fibers to form a composite material. The process involves impregnating the para-aramid fibers with the resin, which then hardens to form a robust matrix structure. This matrix provides a critical protective layer and helps to distribute the force of an incoming bullet or other projectiles over a larger area, reducing the likelihood of penetration.

Unidirectional Direction Technology

Unidirectional technology refers to the structural design where all fibers run in a single, parallel direction. This arrangement allows the strength of the fibers to be maximized, offering increased resistance to ballistic impacts. This technology is instrumental in the effectiveness of para-aramid body armor, ensuring that the force from a ballistic impact is effectively absorbed and distributed, reducing the likelihood of injury. This UD structure, coupled with the polymer film resin matrix layer, contributes to the high performance and durability of para-aramid body armor.

Roll of Aramid Kevlar Fibers - Tacticon Armament
Roll of Aramid Kevlar Fibers

Testing Para-Aramid Fibers for Body Armor

Para-aramid fibers’ performance in body armor is primarily evaluated by two key factors: tensile strength and failure strain. These characteristics help determine the effectiveness of the body armor in absorbing and distributing the force of a ballistic impact.

Para-Aramid Tensile Strength

Tensile strength refers to the maximum amount of stress a material can withstand while being stretched or pulled before breaking. The tensile strength of para-aramid is exceptionally high, meaning that the fibers can absorb significant impact energy before failing.

The tensile strength of para-aramid is typically evaluated using a tensile testing machine, which stretches the material until it breaks, while continuously measuring the amount of force applied.

In addition to its raw tensile strength, the performance of para-aramid can also be influenced by various conditions. For example, extended periods of usage might cause some degree of degradation, although para-aramid is known for its long-term durability.

Temperature and humidity can also affect the performance of para-aramid. Generally, para-aramid maintains its strength properties well in high temperatures and exhibits minimal moisture absorption, which allows it to maintain its protective properties in a wide range of environments.

Para-Aramid Failure Strain

Failure strain refers to the extent to which a material can be deformed (stretched) before it breaks. In the context of body armor, a high failure strain is desirable as it means the material can absorb and distribute more energy from an impact before failing.

The failure strain of para-aramid fibers is tested using similar methods to those used for testing tensile strength, with the material being stretched until it breaks. However, the key measurement here is not the force required to break the material, but the amount of deformation the material can sustain before breaking.

Para-aramid fibers typically exhibit a low to moderate failure strain. This means that while they can sustain a significant amount of force due to their high tensile strength, they do not stretch very much before breaking. This is one reason why para-aramid body armor is often combined with other materials, such as a polymer resin matrix, to help distribute the force of an impact and protect the wearer.

What Is Kevlar?

Kevlar is a synthetic material known as an aramid, which is short for “aromatic polyamide”. It was first developed by Stephanie Kwolek at DuPont in the 1960s and has since become synonymous with bullet-resistant vests and other forms of body armor. Kevlar has been used as body armor, and more recently is a very popular choice for backpack armor.

As a body armor material, Kevlar offers protection against a range of threats, including bullets from handguns, shotguns, and some rifle rounds, as well as knives and other sharp objects. It can also provide protection against shrapnel and other flying debris in explosive scenarios.

Kevlar’s impressive protective properties come from its unique structure. It’s made up of long chains of molecules that are aligned parallel to each other. This gives Kevlar its high tensile strength, allowing it to absorb and distribute the energy of impacts effectively.

Kevlar Tensile Strength

The tensile strength of Kevlar is extraordinary, making it five times stronger than steel on an equal-weight basis. This strength is tested using similar methods to those used for para-aramid, with the material being stretched until it breaks.

Just like para-aramid, Kevlar’s performance can be influenced by various conditions such as duration of use, temperature, and humidity. However, Kevlar is known for its durability and longevity, even under harsh conditions. It maintains its strength properties well in high temperatures and exhibits minimal moisture absorption, allowing it to provide effective protection in a wide variety of environments.

Kevlar Failure Strain

Kevlar’s failure strain is also tested similarly to that of para-aramid. Although Kevlar is known for its high tensile strength, it has a relatively low failure strain, meaning it doesn’t stretch much before breaking. This makes Kevlar effective at stopping bullets, as it can absorb a large amount of energy without deforming significantly.

However, because of its relatively low failure strain, Kevlar body armor is often combined with other materials that can help distribute the impact energy more effectively. For example, a flexible, resin-like material is often used to hold the Kevlar fibers together, allowing the material to “catch” a bullet more effectively.

Para aramid Vs Kevlar Body Armor

When choosing body armor, the material is an essential factor to consider. Both para-aramid and Kevlar are high-performing materials used in the manufacture of body armor. While both offer significant protection against ballistic threats, they each have unique characteristics and benefits that make them suited to specific applications.

Advantages and Benefits of Para-aramid Body Armor

Para-aramid body armor is renowned for its high tensile strength and excellent heat resistance. Its inherent heat resistance allows it to maintain its structural integrity even when exposed to extreme temperatures. This makes para-aramid body armor suitable for operations in both hot and cold environments.

When it comes to weight, para-aramid body armor is relatively light. This makes it ideal for prolonged use as it minimizes the strain on the wearer and allows for better mobility. Further, this type of body armor is fairly thin, making it perfect for use as concealable body armor. 

In terms of protection, para-aramid body armor can provide protection against a range of threats, including bullets from handguns and some rifles, sharp objects, and shrapnel.

Also, para-aramid body armor is made with unidirectional fibers, which allows for excellent energy absorption and distribution. This feature, coupled with its high failure strain, helps to prevent penetration and distribute the force of the impact over a larger area.

Advantages and Key Characteristics of Kevlar Body Armor

Kevlar body armor is most commonly known for its exceptional tensile strength, which is five times stronger than steel on an equal weight basis. This impressive strength allows Kevlar body armor to effectively absorb and distribute the energy of impacts.

Similar to para-aramid body armor, Kevlar offers protection against various threats, including bullets from handguns and some rifles, knives, and shrapnel.

Kevlar is also very resistant to heat and has a low moisture absorption rate. This makes Kevlar body armor suitable for use in a wide range of environments, including those that are hot, humid, or wet.

However, it is worth noting that while Kevlar is highly effective at stopping bullets, it has a relatively low failure strain, meaning it doesn’t stretch much before breaking. As such, Kevlar body armor is often combined with other materials to help distribute the impact energy more effectively.

In conclusion, both para-aramid and Kevlar body armor offer significant protection and have their unique advantages. The choice between the two often comes down to specific needs and operational requirements.

Choose The Right Body Armor For You

Choosing the right body armor can make a significant difference in your safety and performance during tactical operations or emergency situations. Both para-aramid and Kevlar body armor have their unique strengths, but the choice between the two ultimately depends on your specific needs and requirements.

Consider the threat level you’re likely to encounter. Both para-aramid and Kevlar provide effective protection against most handgun threats. However, they do not provide adequate protection against rifle or armor-piercing rounds. Therefore, you should consider the typical threats in your operational environment when choosing your body armor.

Next, consider the weight and comfort. If your operations involve long periods of wear or significant physical activity, you might prioritize lighter and more flexible body armor. Para-aramid body armor and Kevlar are lighter than other forms of body armor and rifle plates but do not offer as much protection.

Environmental conditions are another key consideration. Both para-aramid and Kevlar are heat resistant, but if you’re likely to be operating in very high-temperature environments, the superior heat resistance of para-aramid may be an advantage.

Durability and maintenance are also important. Both materials are durable, but Kevlar’s lower failure strain means it may require more careful handling and maintenance to ensure its longevity.

Lastly, consider the cost. High-quality body armor is an investment in your safety, but your budget may dictate your options. Generally, Kevlar tends to be more expensive than other para-aramids.

The decision between para-aramid and Kevlar body armor should be based on a comprehensive understanding of your operational needs, environment, and resources. Always prioritize your safety and ensure that your chosen body armor meets or exceeds the NIJ standards for the threat level you are likely to encounter. 

Kevlar and Para-aramid Body Armor FAQs

What are Kevlar plates made of?

Kevlar plates are made from Kevlar, a high-strength synthetic fiber developed by DuPont. It’s composed of long chains of molecules aligned parallel to each other. These chains are then bonded together, providing high tensile strength and rigidity.

What type of material is Kevlar?

Kevlar is an aramid fiber, which is a type of synthetic, heat-resistant fiber. Its exceptional tensile strength, and lightweight, and heat-resistant properties make it an ideal material for body armor.

How long do Kevlar plates last?

The lifespan of Kevlar plates can vary depending on their use and care. However, most manufacturers recommend replacing Kevlar body armor every 5 years.

Is Kevlar more bulletproof than steel?

Kevlar and steel provide different types of protection. While Kevlar is excellent for absorbing the energy of bullets and reducing the risk of penetration, it cannot provide the same level of protection against rifle rounds as steel can.

What is the difference between aramid and Kevlar?

Kevlar is a type of aramid fiber. Aramid is a class of heat-resistant and strong synthetic fibers, and Kevlar is a specific brand of aramid fiber developed by DuPont.

What is para-aramid fiber?

Para-aramid fiber is a type of aramid fiber characterized by its exceptional tensile strength, high heat resistance, and lightweight. It’s used in various applications, including body armor, due to its excellent protective properties.

What is the difference between aramid and para-aramid?

The main difference between aramid and para-aramid lies in their molecular structure. While both are strong and heat-resistant, para-aramid fibers like Kevlar and Twaron have a parallel orientation of molecules, resulting in higher tensile strength and rigidity.

What are the disadvantages of Kevlar?

While Kevlar is strong and heat-resistant, it can degrade over time, especially with exposure to sunlight and moisture. It’s also not effective against rifle or armor-piercing rounds as hard armor plates, like ceramic or steel.

How long does aramid last?


The lifespan of aramid body armor can vary, but most manufacturers recommend replacing it every 5 years. The actual lifespan can be longer or shorter depending on how it’s used and cared for.

Can Aramid stop a bullet?

Yes, aramid fibers like Kevlar and Twaron are commonly used in bulletproof vests and other types of body armor. They are designed to absorb the energy of a bullet and distribute it across a larger area, reducing the risk of penetration.

What is better, Aramid or Kevlar?

Kevlar is a type of Aramid fiber, so the choice between Kevlar and another type of Aramid fiber depends on the specific properties and requirements of the application. In terms of body armor, both Kevlar and other para-aramid fibers can provide effective protection.

Can Kevlar alone stop a bullet?

Yes, Kevlar can stop certain types of bullets when it’s layered to form body armor, particularly those from handguns. However, it may not provide sufficient protection against rifle or armor-piercing rounds. In such cases, additional hard armor plates may be needed.

Final Thoughts

Choosing the right body armor is important and requires understanding the properties, advantages, and potential drawbacks of the materials involved. Both Kevlar and para-aramid body armor offer robust protection, particularly against pistol and non-armor piercing rounds, thanks to their high tensile strength and energy-absorbing properties.

Ultimately, the choice between Kevlar and para-aramid, or any other type of body armor, should be guided by your specific needs, risk assessment, and operating environment. And remember, taking care of your body armor and replacing it when necessary is as important as choosing the right kind in the first place.

The opinions expressed in this post are those of the author and do not necessarily reflect the views and opinions of Tacticon Armament.

One thought on “Kevlar vs Para-Aramid: A Comparative Overview

  1. Hometown Trinity Heroes says:

    This is great information to inform our customers of. This information helps us better explain the different products and differences. Thank you!

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