Kevlar - what kind of fabric. Kevlar - fabric for heroes Kevlar: defending in comfort

29.06.2023

Kevlar(English) Kevlar) is a fabric of para-aramid (polyparaphenylene-terephthalamide) fiber manufactured by DuPont. Kevlar has high strength, surpassing some metals in these features (five times stronger than steel, tensile strength σ 0 = 3620 MPa). Kevlar was first obtained by Stephanie Kwolek's group in 1964, the production technology was developed in 1965, and commercial production began in the early 1970s. Lightweight, durable and safe material Kevlar can significantly improve the performance of workwear and protective equipment. Today, Kevlar is used in the manufacture of products that require high wear resistance of materials: climbing ropes, quickdraws, helmets, shoe uppers, backpacks , skis , gloves, as well as for the manufacture of overalls. Kevlar fiber has a small weight (in terms of strength characteristics it surpasses steel, but much lighter in weight.) and high resistance to various kinds of influences. It has properties such as incombustibility and heat resistance.

Kevlar is a yellowish para-aramid fiber with very high strength. Tensile strength up to 360 kilograms per millimeter square. An artificial analogue close to the web, or at least created when trying to reproduce similar material. Tensile strength is 3 times higher than strong steel at the same thickness. But the specific gravity of steel is five times higher, therefore, with the same weight of materials, Kevlar will be 15 times stronger. The range of application is very large.

Initially, the material was developed for reinforcing car tires, for which it is still used. Besides, kevlar used as a reinforcing fiber in composite materials, which are strong and light.

Separate threads reinforce fabrics of various overalls, Kevlar fabrics are used in the use of bulletproof vests. Kevlar gloves protect hands from high temperatures and damage from sharp objects. As composite materials, Kevlar fibers are mainly used in mixtures with other materials: carbon and fiberglass. Kevlar has 3 times the tensile strength of fiberglass but is twice as light. Kevlar is sold in threads, fabrics, ribbons and the price per kilogram is about the same as that of carbon. The range of prices here is much higher, since kevlar used not only as composite materials, fabrics and tapes also have a price as a product, and not just as a raw material. For example, ballistic fabrics for body armor.

gloves and protective inserts in sportswear (for motorcycling, snowboarding, etc.). It is also used in the shoe industry for the manufacture of anti-puncture insoles.

Strong Kevlar fibers have long been woven into the structure of developments in the auto, construction, and military industries, partly replacing the least strong and comfortable steel. The material "woven" from organic threads has become simply indispensable due to its unique features. So now let's take a closer look at the question of kevlar- what is it, and learn the history of its occurrence.

History of Kevlar

The new polymer, in a sense, became the “child” of His Majesty Variant, having been born in the laboratories of Dupont, which even then had to its credit the invention of such a material as nylon. Then, in 1964, a research group found a solution on how to change the metal cord in car tires to significantly lighter polymer threads, such as polyaramid. Accordingly, the lesson was not out of the ordinary, since polyaramids must be dissolved beforehand (which in itself is not an easy task), and only then “spin” threads from the resulting mass. A good result was achieved by Stephanie Kwolek. She was able to obtain fibers of exceptional strength, which, after testing, showed stunning results - the new thread was stronger than steel.

It is symbolic that the inventor of this unique fiber, Stephanie Kwolek, loved to sew clothes for dolls as a child. As a child, Stephanie Kwolek wanted to become a fashion designer: she came up with patterns on her own, and when her mother was not at home, she made her way to the sewing machine to sew the next doll dress. After high school, she majored in chemistry at Carnegie University, but dreamed of medicine. In order to earn money for studying at the university, in 1946 the girl began working in the famous Dupont concern, and soon realized that her vocation was chemistry after all. In 1964, the Kwolek group was working on improving the production of polyaramids, polymeric substances with a rod-like structure that could replace steel cord in tires (in order to save fuel). By abandoning the melt method, Stephanie was able to create an unusual-looking solution that, when passed through spinnerets, turned into aramid threads. Stephanie Kwolek's group has worked with polyaramids, which have rod-shaped molecules. Polymer fibers are usually made by spinning while extruding the melt through thin holes - spinnerets. However, polyaramid melts with difficulty, and therefore it was decided to use solution spinning. Finally, Stephanie managed to find a solvent, but the solution was cloudy and opalescent and looked like moonshine (instead of being clear and thick like molasses). The spinning engineer categorically refused to pour such a muck into the machine because of the risk of clogging the thin spinnerets. Stephanie, with great difficulty, persuaded him to try to draw a thread from such a solution. To everyone's surprise, the thread stretched perfectly and was exceptionally strong. The resulting yarn was sent for testing. When Stephanie Kwolek saw the results, her first thought was that the device was broken - the numbers were so high. However, repeated measurements confirmed the phenomenal properties of the material: it was five times superior to steel in terms of tensile strength.

Almost simultaneously, similar fibers (SVM and Twaron) were created in Russia and Europe, but since Kevlar was the first, all materials belonging to this group began to be called that way.

In 1975 a new material, Kevlar, was released to the market. Now it is used almost everywhere: cables, car and boat bodies, sails, aircraft fuselages and spacecraft parts are made from it, skis and tennis rackets. But the fact that Kevlar is made into bulletproof vests For police And suits firefighters, Stephanie Kwolek is especially proud that this (and others) use of Kevlar has helped save millions of lives.

The new material, called Kevlar, came into commercial use in the 1970s. It began to be used for the production of tires, cord tapes, composite materials. At the same time, military and law enforcement agencies paid attention to the high strength of polyaramid fibers, the purpose of which was to develop personal protective equipment. The idea of body armor dates back to World War I (author Conan Doyle), but the traditional metal plates were heavy and hindered movement.

Specialists of the American National Institute of Justice conducted thorough research for several years, during which they proved that Kevlar fabric in seven layers provides resistance to a bullet shot for the most common 38 caliber. The last stage of field tests showed that the strength of such body armor decreases when it gets wet and when exposed to UV rays. It has also been found that Kevlar fabrics lose their protective properties after several washes, and that they do not tolerate bleaching and dry cleaning.

The result of the developments was the Kevlar body armor coated with a waterproof fabric that protects the reinforced layer from water and the sun. In addition, Kevlar was used as personal protective equipment. helmets , gloves, shoe insoles, etc.

But this was only the beginning of the brilliant history of this material. Kevlar fabric appeared on the market in 1975, and since then there is no need to complain about the lack of demand. And he gives birth to creation, so Dupont does not stop there. The company is making a sizable cash injection to upgrade the patented Kevlar material with improved features.

Modern Kevlar is a surprisingly light and soft material that does not burn in fire and even practically does not smolder, absorbs water perfectly, allowing the skin to “breathe”, and at the same time surpasses steel at times, withstanding a tensile load within 2500 N. Well, fabric processing is quite easy and does not require narrow-profile equipment.

How they create

Kevlar fibers are a crystallizing polymer. Their structure is distinguished by the highest degree of rigidity. This is justified by the presence of benzene rings. By structure, Kevlar refers to network polymers.

Fiber-forming polymers are made at low temperature by solution polycondensation. Reagents are added to the latter and actively mixed. From this solution, a polymer is released in the form of a crumb or gel. Then it is washed and dried. Then the polymer is dissolved in strong acids (for example, in sulfuric). Threads and fibers are formed from the resulting solution by extrusion (formed through spinnerets). The filaments and fibers are then fed into the spinning bath, washed and dried again.

Kevlar is produced in the form of:

technical threads;
yarn;
roving;
fabrics.

Kevlar is made in the form of technical threads with different linear density and structure. The number of fibers in the threads can be different: from 130 to 1000 in the production of Kevlar fabric and from 500 to 10 thousand in the manufacture of cord and ropes. This material is available in the form of roving, fabric and yarn. The fibers are opaque, their average diameter is -11 microns.

Properties of aramid fibers

Para-aramid fiber is characterized by high mechanical strength. Depending on the brand, the tensile strength of the fiber can range from 280 to 550 kg / mm² (for steel, for comparison, this parameter is in the range of 50-150 kg / mm².
Only the highest-strength steel grades with special treatment come close in strength to the weakest grades of aramid).
Such high strength is combined with a relatively low density - 1400-1500 kg / m³ (density of pure water is 1000 kg / m³, the density of steel is about 7800 kg / m³).

Aramid (Kevlar) It is used both in pure form of fiber and fabric, and in composite materials based on various resins. Synthetic aramid fiber has the highest strength (tensile strength 250-600 kg/mm2) with a low density of 1400-1500 kg/m3, high resistance to impacts and dynamic loads with such unique characteristics, the fiber has high thermal stability, is able to work at high temperatures and considered difficult to combust. In composite materials, aramid is used as a reinforcing material, such composites are called organoplastics, they have high specific tensile strength and minimal weight. The fibers have yellow color.

The usual fiber diameter is 1 µm, opaque.

The main characteristic of the material is its high mechanical strength. Density and, accordingly, mass are quite low.
Kevlar is stretch resistant.
It does not burn or melt, it has the ability to self-extinguish. Begins to decompose at temperatures above 430 °C. When exposed to high temperatures, it begins to lose strength only over time, not immediately.
Has resistance to organic solvents.
It has a high modulus of elasticity.
Resistant to corrosion.
Under the influence of very low temperatures (cryogenic) not only does not deteriorate, but also becomes even stronger.
It has low electrical conductivity.
Cut resistant.

Kevlar fibers are made up of long molecular chains made from polyparaphenylene terephthalamide. The chains have a highly ordered orientation with strong intermolecular bonds, resulting in a unique combination of characteristics:

Main characteristics of Kevlar:

Highly modular
- Load at Specific Elongation (LASE)
- High specific tensile strength at low weight
- Low elongation at break (structural rigidity)
- Low electrical conductivity
- High chemical resistance
- Low thermal shrinkage
- High rigidity (measured by breaking work)
- Excellent dimensional stability
- High cut resistance
- Fire resistant, self-extinguishing

In addition to high strength, Kevlar has many other unique properties, namely:

in contact with fire and high temperatures, this fiber does not burn, smoke or melt;
Kevlar is non-toxic and non-explosive;
its thermal decomposition temperature is 430-450 degrees;
the strength of armide fibers begins to gradually decrease when heated to more than 150 degrees;
when freezing, Kevlar only becomes stronger, it is able to withstand cryogenic temperatures (up to -200 degrees);
this material is an electrical insulator.

In addition, Kevlar fabric is soft, hygroscopic and breathable, and is quite comfortable to use. True, this does not apply to clothing designed to work in conditions of open fire and high temperatures. To increase heat resistance, Kevlar is coated with aluminum. The material of such a fiber reliably protects against powerful thermal radiation, contact with hot surfaces up to 500 degrees, as well as splashes of hot metal.

It should also be added that this material is quite light - one meter of fabric weighs 30-60 g, and although it is not cheap (from $ 30 per square meter), its excellent protective properties justify such expenses. Protective materials reinforced with Kevlar threads are somewhat cheaper, which makes them resistant to tearing and abrasion. Such fabrics are used for protective inserts in work and sportswear, gloves, and also as wear-resistant insoles. Caring for their products is extremely easy. They should not:

wash often;
clean with chemicals;
expose to sunlight.

Due to its high characteristics, aramid fiber has found the widest application in a wide variety of industries. The most famous application of the fiber is protective equipment: bulletproof body armor , helmets and fire protection, for example suits for firefighters and gloves. Also, aramid fiber is used to reinforce car tires, fiber-optic cables, acoustic speaker cones, for the manufacture of heavy-duty cables, tapes and fabrics. Aramid fibers have been widely used in composite materials based on vinyl ester and epoxy resins. Due to their unique properties, such composites are used in aircraft and rocket manufacturing for the manufacture of various parts working in tension, in internal pressure vessels, and high-speed flywheels. In combination with other reinforcing materials, aramid fibers are used in shipbuilding for the production of hulls for premium yachts, boats and boats or for military purposes. The use of composite materials with aramid has also found its place in astronautics, along with carbon fiber, where it has become indispensable in some units and details. Widespread in the field of car tuning and motorsport, aerodynamic body kits, seats, interior elements and load-bearing structures are manufactured.

Kevlar fabrics, aramid fabrics, hybrid fabrics and carbon fabrics are characterized by the following parameters:

The type of fiber used in the fabric, both warp and weft (aramid fiber or carbon fiber).
Weave density (the number of threads contained in 10 mm of carbon fabric, both warp and weft).
The number of filaments in 1 thread of fabric (the number of microfiber threads per 1 thread of weaving).
Type of weaving fabric: straight, herringbone, satin, knitted.
Surface density of fabric (weight per square meter): 90g/m sq-640g/m sq
Thickness of fabric: 0.1mm -0.65mm
Fabric width: 10mm-1500mm.

Thermal Properties of Kevlar

Kevlar retains strength and elasticity at low temperatures, down to cryogenic (−196 ° C), moreover, at low temperatures it even becomes a little stronger.

When heated, Kevlar does not melt, but decomposes at relatively high temperatures (430-480 °C). The decomposition temperature depends on the rate of heating and the duration of exposure to temperature. At elevated temperatures (above 150°C), Kevlar's strength decreases over time. For example, at 160°C, the tensile strength decreases by 10-20% after 500 hours. At 250°C, Kevlar loses 50% of its strength in 70 hours.

Comparison of Kevlar and fiberglass

Kevlar has 2.5 times the strength and 3 times the stiffness of electrical fiberglass while being only 43% as dense as glass fiber. It better resists fracture, vibration, and crack propagation, and holds shock loads superbly. Kevlar fiber fabric is similar in construction to fiberglass, but unlike it does not require any special treatment. As it may seem at first, Kevlar is just an ideal material for pasting the case, but in fact, not everything is so smooth here.

The main obstacle to the use of Kevlar for external protection of the hull is its rather mediocre resistance to abrasive influences, and this property is in the first place among the requirements for the pasting material. As soon as Kevlar begins to undergo abrasion, its strength immediately drops. Plus, with a much greater tensile strength than fiberglass, it loses to it in bending and is two times weaker in compression. Kevlar can be used in gluing to increase the impact resistance of the hull, however, it is recommended to additionally protect it from abrasion from the outside with fiberglass or similar material, thereby also facilitating subsequent puttying and sanding.

The behavior of Kevlar under compression is very different from fiberglass. Whereas a fiberglass laminate breaks rapidly and extensively under high stress, a Kevlar laminate under compression resembles that of a ductile metal—it flexes and forms dents. Although this may seem like a valuable quality, it should be added that this occurs at relatively low loads, and therefore the resin breaks down with the formation of cracks and delamination.

This weakness of Kevlar can be compensated to some extent in a number of ways. Firstly, a layer of Kevlar can be pasted over on top with another material - for example, fiberglass. However, in the case of hull wrapping, the strength factor of the material is secondary and this practice leads to an unnecessary increase in cost and weight. Nevertheless, this material can be used for local reinforcements - for example, at the seams. Secondly, there are "hybrid" fabrics containing, in addition to Kevlar, glass and (or) carbon fibers that compensate for the weaknesses of Kevlar, but they are also of little use for pasting purposes.

These are not the only difficulties associated with Kevlar. The material is UV degradable and should not be exposed to the sun unless protected by a pigmented resin or other coating containing an UV inhibitor. Unlike fiberglass and similar materials, Kevlar does not become transparent when impregnated with resin and retains yellow shade. This not only gives the boat an untidy look (in the case of a natural finish, its use is completely meaningless), but also does not allow (at least for a non-professional) to determine the degree of impregnation of the material with resin.

Other properties of Kevlar speak for themselves. Due to its strength, Kevlar is very difficult to cut, both in the form of fabric and in the form of a laminate, a carbide cutting tool is required to work with it. tool. Grinding the surface pasted over with Kevlar is practically meaningless - the material forms an abundant pile. When working with Kevlar, care must be taken not to form hard folds - this leads to damage to the fibers and loss of strength. As a rule, Kevlar fabric does not require lamination in several layers. The reason lies in the fact that adhesion problems can occur between two layers of Kevlar and, if such a laminate is required, there must be a thin layer of glass mat between them. Since glass and Kevlar fibers have approximately the same (3%) elongation under load, they are appropriate in this design.

Kevlar is produced without the use of any kind of emulsion and can be used with various types of resins, including polyester, vinyl ester and epoxy. However, in order to realize high impact resistance and other high material performance in plastics, vinylester and epoxy resins are generally recommended. But even with this, the tear and tear strength is less than that of the same Vectra fabric when using them alone as a body pasting material.

Comparing all the pros and cons of Kevlar, we can conclude that the negative aspects still prevail, at least when it comes to pasting. The cost of Kevlar fabric is many times higher than that of fiberglass, even though the material is becoming more widely available through other applications.

Kevlar fiber fabric is commonly called Kevlar-49 and is sold in different densities in rolls of 95 and 125 cm wide. It can hardly be recommended for pasting the case, however, local reinforcements paired with fiberglass protection can be of practical use.

Areas of application of Kevlar

This high tenacity fiber is used in a wide range of applications, from the aviation and aerospace industries to sportswear and travel apparel. Kevlar enters the market in the form of threads, cord, fabric, and also as a component of composite and blended materials.

The main ways to use it are:

Initially, the material was developed for reinforcing car tires, and it is still used in this capacity. In addition, Kevlar is used as a reinforcing fiber in composite materials, which are strong and lightweight.

Kevlar is used to reinforce copper and fiber optic cables (thread along the entire length of the cable to prevent stretching and tearing of the cable), in acoustic speaker cones and in the prosthetic and orthopedic industry to increase the wear resistance of carbon fiber foot parts.

Kevlar fiber is also used as a reinforcing component in mixed fabrics, giving products from them resistance to abrasive and cutting effects, such fabrics are made, in particular, protective gloves and protective inserts in sportswear (for motorcycling, snowboarding, etc.).

In workwear, fabric with Kevlar fiber is used mainly for reinforcing pads in the knee area (knee pads) and elbow area. Because Kevlar fabric has high indicators for abrasion, then it is used in clothes in those places where the load on abrasion, cuts and punctures is greatest.

Kevlar finds its application in those industries where wear resistance and thermal stability, low structural hardness and the greatest lightness, as well as good strength at low weight are very important. Therefore, it is logical that this material came "to the court" in the manufacture of personal protective equipment, namely bulletproof vests, helmets.

Today, different clothes are made from Kevlar, intended not only for military personnel and various special forces, but also for those who choose an ultra-active lifestyle and are obsessed with the same hunting or airsoft. Naturally, an airsoft player does not need Kevlar armor with the highest level of protection and additional armor plates, but t-shirt with special Kevlar inserts will be very appropriate. In addition, such elements are easy to hide under outerwear, and models suitable for design have been developed.

Perhaps the most popular Kevlar products can be considered armored helmets, tactical gloves and of course, body armor. By the way, it is from this fabric that the means of passive protection adopted by NATO are made.

Means of individual armor protection

The mechanical properties of the material make it suitable for the manufacture of personal armor protection (PIB) - bulletproof vests and armored helmets. Studies of the second half of the 1970s showed that Kevlar-29 fiber and its subsequent modifications, when used in the form of multilayer fabric and plastic (fabric-polymer) barriers, show the best combination of energy absorption rate and duration of interaction with the impactor, thereby providing relatively high, at a given mass of obstacles, indicators of bulletproof and anti-fragmentation resistance. This is one of the most famous uses of Kevlar.

In the 1970s, one of the most significant developments in the development of body armor was the use of Kevlar reinforcing fiber. Development of Kevlar Body Armor by the National Institute of Justice USA(English) National Institute of Justice) took place over several years in four stages. The first step was to test the fiber to see if it could stop a bullet. The second stage was to determine the number of layers of material needed to prevent penetration by bullets of various calibers and flying at different speeds, and to develop a prototype vest capable of protecting employees from the most common threats: .38 Special and .22 Long Rifle bullets. By 1973 it had developed vest of seven layers of Kevlar fiber for field testing. It was found that when wet, the protective properties of Kevlar deteriorated. The ability to protect against bullets also decreased after exposure to ultraviolet light, including sunlight. Dry cleaning and bleaching also took a toll on the protective properties of the fabric, as did repeated washes. To circumvent these problems, a waterproof vest, coated with fabric to prevent exposure to sunlight and other negative factors.

Tactical gloves with Kevlar in the form of protective inserts on the palms and knuckles, they allow not only to protect the hand from damage in a collision, for example, with the teeth of the enemy, but also to significantly increase the blow, making it crushing. This is a typical modern analogue of brass knuckles. Given the strength, warmth and resistance to moisture and damage, such devices will soon be popular not only among employees of specialized units, but also among extreme sportsmen, street fighters, and lovers of an active lifestyle. They are also in demand among those for whom the black streets of their native settlement cause completely justified fears.

Bulletproof vest Kevlar is rightfully considered one of the better means of personal passive protection. Due to its unique lightness, strength and relative durability, such “armor” is able to protect the wearer from the sliding blows of a cool gun and mitigate the effects of bullets, preventing the penetration and spread of fragments.

Choosing body armor, in the basis of which this polymer is used, one should take into account some aspects with which it is endowed. Kevlar - what is it? Soft armor, which will not help out from a point-blank shot or a penetrating blow with a knife or awl, therefore models have been developed with special rigid panels designed to additionally absorb the blow.

The shortcomings of Kevlar include light sensitivity - with prolonged exposure to sunlight, the miracle material begins to collapse, albeit very, very slowly. Sewing parts with Kevlar threads into a denser fabric became a good means of protection.

The cost of products with paraamide threads is quite high, and this specifically prevents the general "Kevlarization". Only economically developed countries can afford to equip the army with tactical products from this material.

Today it is very difficult to imagine passive protection without Kevlar fibers, but made from such a fabric body armor and helmets helmets saved a lot of lives. Because the creators have something to be proud of. And manufacturers need to expand the creation of Kevlar and constantly ennoble the properties of its properties.

The latest Kevlar fiber innovations for body armor are Kevlar XP fibers, AS 400 (Anti Stab) and IC 600D (impact control) impact control material - the new Kevlar XP technology will reduce internal deformation by 15% or more. You can also expect a 10% reduction in overall weight.

With the Kevlar AS 400, DuPont is responding to the demands of the market for more sophisticated and advanced protective equipment that can protect the wearer from a variety of dangerous situations: knives, spikes, bullets, shrapnel wounds and blunt impacts.

Kevlar IC 600D is a soft armor component that gives the wearer a chance to survive a gunshot or shrapnel wound while being comfortable and flexible enough for everyday use. socks .

The use of Kevlar in workwear

Protective cloth, made from DuPont Kevlar fiber, is the perfect solution for workers exposed to cut, abrasion and hot object hazards. From automotive manufacturing to glass transportation, computer assembly and metal stamping, cloth made with Kevlar technology meets the performance and safety requirements of a wide variety of industries. This allows workers to work safely and comfortably in the toughest environments, fully exploiting their potential.
When you decide to dress your workers in Kevlar protective clothing, you will find that there is a wide variety of products to choose from. From gloves and mittens to sleeves and other clothing. All Kevlar protective products provide the protection you need against cuts, punctures and hot objects, while providing the flexibility and comfort your workers need to perform their jobs.

The reinforcing properties of Kevlar are used, including it in the composition of the fabrics from which the elements of protective clothing are made: gloves, individual inserts in costume, knee pads, anti-puncture insoles, clothing for a sports group - for snowboarding, motorcycling, etc. Such a fabric becomes resistant to cuts and punctures.

For work environments that require a high degree of cut protection, cleanliness or tactile precision, product manufacturers using Kevlar fiber offer the following:

heat resistant gloves made from branded fiber kevlar, provide essential thermal protection in extreme environments where workers are exposed to extreme heat and sharp objects.

Kevlar gloves they can protect against cuts on glass, short-term exposure to flames and hot objects, while they are soft, elastic and breathable (they look like knitted fabrics) and allow you to work with even the smallest details, as they do not violate the sensitivity of the hands.

When working with metal and forming glass products, heat-resistant gloves are an absolute must to keep your workforce safe and productive. Heavyweight gloves and terry cloth mitts, 100% Kevlar terry cloth, are suitable for use in steel production or in applications where workers are exposed to extreme heat and sharp objects. For added protection, liners are available in wool or DuPont Nomex.

This high level of protection is also available in an outer layer of mittens made from woven Kevlar. The outer material of these gloves is 100% woven Kevlar fiber material and the pads can be made from Nomex or wool. These gloves are designed for use in high temperature applications where workers are exposed to hot, sharp objects, such as casting machining, where sharp burrs would be a problem.

And, due to the extreme hazards of working at high temperatures, the exceptional performance found in industrial heat-resistant gloves made from Kevlar can also apply to Kevlar sleeves. Armlets come in tubular knitted or woven cut-and-sew varieties and offer a wide range of protection from the shoulder to gloves .

When working with metal and hot surfaces and forming glass products, gloves, which offer the highest level of protection against multiple hazards and high temperature work areas. Therefore, manufacturers offer many options for heat resistant Kevlar gloves to meet your needs.

Shipbuilding

Since the early 1990s, Kevlar has become widespread in shipbuilding. Due to technological difficulties and the price of Kevlar, it is used selectively. For example, only in the keel part or for finishing the hull at the seams. It is used for the construction of yachts. From this material, they are very light, consume less fuel and are able to reach higher speeds. Many manufacturers (such as the shipyards BAIA Yachts, Blue water, Dolphin, Danish yacht, Zeelander Yachts), making a small number of yachts a year, are systematically switching to the use of Kevlar. One of the leaders in the production of Kevlar yachts is the Italian shipyard Cranchi, which produces Kevlar yachts ranging in size from 11 to 21 meters.

Aviation industry

Kevlar is used in the design of a number of unmanned aerial vehicles (for example, RQ-11) to increase protection.

Currently, Kevlar has become a familiar component of clothing and equipment for people whose lives are constantly in danger: the military and security forces, astronauts and researchers, athletes and firefighters. Kevlar fibers are used everywhere where increased strength is required, from car tires to yacht hulls, the scope of their application is constantly expanding, and the production technology is improving. This material was obtained half a century ago, and many will find it strange that a woman became its author.

Kevlar in sporting goods

The need for lighter, stronger and safer sportswear has made Kevlar a popular choice for both product manufacturers and consumers. The same qualities and performance that have proven themselves in industry and in life and health equipment come to the service of professional athletes and amateurs, as well as everyone else who needs the best quality sports products.

The legendary strength and light weight of Kevlar fiber is just the beginning. Its natural toughness allows the fabric and threads to withstand constant impact and other loads. Kevlar helps minimize vibration transmission and withstands deformation loads without breaking. Because the ductility of the material prevents it from crushing or other types of severe damage that are common with CFRP or fiberglass, it is safer and more reliable in high impact environments.

The widespread use of DuPont Kevlar in a wide variety of industries has inspired many consumer product manufacturers to create products that include Kevlar. The benefits of Kevlar's exceptional strength, cut resistance and light weight are highly valued by customers looking for durable products that are easier to use, transport and store. Kevlar's strength-to-weight advantage over other materials means that products using Kevlar are often not only lighter than their non-Kevlar counterparts, but also smaller.

Skis, snowboards, helmets, boats and Kevlar oars have very high strength and lightness.

Other areas

Kevlar is used as a reinforcing fiber to give the material strength and lightness. They strengthen the cables by threading a Kevlar thread along the entire length, protecting it from stretching and breaking.
It is also used for the manufacture of orthopedic prostheses.
Kevlar ropes are characterized by high strength, light weight, corrosion resistance, non-electrical conductivity, due to which they are widely used in shipbuilding and mining, where they replace steel cables.
The strength properties of Kevlar fibers are combined with the heat resistance of carbon and a hybrid material is obtained - carbon-Kevlar. It is used to build boat hulls capable of high speeds.

Due to its high strength and resistance to external mechanical and chemical influences, Kevlar is widely used in various fields and is recognized as one of the most high-tech modern materials.

Types of Kevlar fibers and materials

Kevlar fibers are used to make various types of clothing, accessories and equipment to increase their safety and durability. This fiber is five times stronger than steel for the same weight, making it the best material for workwear and personal protective equipment.

DuPont Kevlar is a para-aramid (aromatic) polyamide) fiber, which is produced in a wide variety of forms, each designed for specific applications associated with the production of various consumer and industrial products. DuPont offers Kevlar as cut fibers that can be spun into yarn or thread, continuous filaments, fibrillated pulp, and sheets to provide strength to mechanical paper. As our customers continue to use Kevlar to improve performance and safety, DuPont is constantly working to open up new opportunities for Kevlar applications.

Kevlar - Aramid pulp

DuPont Kevlar Pulp is a fibrillated chopped fiber that can be used in the form of specialized additives designed to improve performance, providing excellent levels of reinforcement and viscosity control under shear stress conditions. Kevlar pulp is used in automotive brake pads, oil seals, friction paper for automatic transmissions, and as a viscosity control additive in adhesives and sealants.

Characteristics

Kevlar - threads and filaments

There are many different types of DuPont Kevlar yarns and filaments, each with their own qualities and performance characteristics. Depending on the final application, one or another type of Kevlar is selected.

Various types of Kevlar fibers and threads, each with a unique set of properties and characteristics, and designed for specific applications.

Kevlar 29 (K29)

A family of Kevlar threads, with the same strength properties and having different texes and lubricants. These threads are used in the production of ballistic protection equipment, cables and cables, cut-resistant gloves, personal protective equipment such as helmets, armor plates for cars, as well as for reinforcing the rubber of car tires and hoses.

Kevlar 49 (K49)

High modulus yarns primarily used in fiber optic cables, textiles, plastic reinforcement, wire rope, cable, water sports composites, and aerospace.

Manufacturer-dyed Kevlar thread used in the production of ropes and cables, tapes and belts, gloves and other protective clothing, and sporting goods.

Types of threads with increased relative elongation, resistant to fatigue stresses, used in the manufacture of rubber products, such as: car tires, belts and hoses.

Threads with increased specific strength used in the production of personal protective equipment: body armor and helmets, as well as cables, cables and high-pressure hoses used in the oil and gas industry.

Fiber for reinforcing fabric for the production of body armor (bulletproof vests and helmets), as well as anti-fragmentation protection.

Kevlar KM2 Plus

High-strength, impact-resistant and thin fiber used for the production of bulletproof vests and helmets for the military and employees police .

Kevlar AP fiber significantly improves cost effectiveness and allows for more design freedom, allowing manufacturers to create lower cost and more reliable consumer and industrial products.

There are also other types:

staple-kevlar- short cut fibers with a length of just over six mm. Strength properties are lost due to cutting, but barrier properties are preserved. It is used for the production of yarn, felt and non-woven products with high heat-insulating and vibration-insulating properties;

flock kevlar- crushed fiber (up to 1 mm), used for reinforcing various resins.

Kevlar fabrics also have disadvantages:

lose strength during abrasion;
destroyed by ultraviolet light. Requires special resin coating.

Kevlar paper for aerospace applications

The high strength, light weight, and temperature stability of paper made from DuPont Kevlar allows aerospace and marine equipment manufacturers to produce safer parts that perform better and last longer than their alloy counterparts. The use of DuPont Kevlar honeycomb cores in the aerospace industry reduces the weight of parts and contributes to lower operating costs. And because Kevlar is an electrical insulator, it can prevent galvanic corrosion between dissimilar materials such as metals and graphite-filled composites.

Each honeycomb panel contains paper and a bonding resin. Sheets of Kevlar paper are cut, glued, folded into hexagonal meshes and dipped in a bonding resin. The final product resembles a honeycomb and contains 90-99% empty space, providing exceptional weight savings and structural strength.

Kevlar - Yarn / Felt

Kevlar yarn is made from staple fibers and is usually produced on ring spinning machines. This yarn can be used to weave or knit various types of protective fabrics and is primarily used for knitting seamless gloves and sleeves. Usually such yarn is used in the market of heat- and cut-resistant products. Kevlar yarn provides more comfort than multifilament yarn. needle-punched felt Kevlar is made from staple fibers and is usually produced on ring spinning machines. Such felt commonly used as lining material for various personal protection products: gloves , boots, protective pants for working with a chainsaw.

needle-punched felt Kevlar material exhibits excellent heat and cut resistance and provides good puncture protection. Due to its stiffness and shedding of fibers during material processing, needle-punched felt Kevlar is more often used not as an outer fabric, but as a backing material.

Products for personal protection

Kevlar fiber helps save lives and protect law enforcement, corrections and military personnel from serious injury with an ever-expanding line of products designed to provide bulletproof, splinterproof and puncture protection against small arms firearms.

A high-strength Kevlar brand used in the manufacture of bulletproof vests and helmets for ballistic protection.

Kevlar Comfort XLT

Provides law enforcement officers with excellent ballistic protection and allows the manufacture of body armor, which are at least 25% lighter than all other aramid fabrics.

Kevlar Correctional

A technology that helps protect correctional officers from the threat of injury from various improvised and homemade weapons: sharpeners, awls, etc.

High-strength and high-viscosity anti-bullet and shrapnel fabric for the military USA which reduced the loss of personnel.

Kevlar MTP Technology

Patented technology to protect against small arms, homemade stabbing weapons and factory-made knives.

car armorKevlar

Bulletproof and anti-fragmentation protection for armored military vehicles and civilian cars operating in hazardous conditions.

Aramid fiber Kevlar allows you to achieve more. It enhances the safety and durability of clothing, accessories and equipment. Lightweight, durable and extremely impact resistant material. Aramid fiber Kevlar is widely used in the manufacture of armor to protect against firearms, stab and shrapnel wounds and is constantly improving, allowing heroes to always be heroes. It is also used to equip ski slopes and hiking trails, in difficult desert conditions and even in outer space.

The Kevlar fiber was invented over 50 years ago, but even now, scientists continue to work on new possibilities for this amazing material in collaboration with various communities, manufacturers and governments. Together we make Kevlar even stronger, stronger and more efficient. Aramid fiber Kevlar pushes the boundaries of what is possible every day and allows you to cope with difficulties.

Proper care and use

Given all these indicators, you need to keep in mind that frequent washing (even dry cleaning) will not benefit things made of fabric. kevlar, so this should be done as needed. Since Kevlar is resistant to heat treatments, it can be safely ironed, but it is better to dry it in the shade, away from the daytime star.

The area where these threads are used is expanding more and more: they began to be mixed with other elements to give things high strength indicators. Various types of protective overalls, body armor, tires, protective gloves, jeans and more. Although progress is constantly coming on its heels, Kevlar can be deservedly called a modern fabric that will provide its owner with protection from damage and maintain a sense of security.

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Gender: male Season: summer Protective toe cap: Composite (MUN 200 J) Shoe type: low shoes Brand: SCENDA Upper material: Genuine leather Velor Lining material: wear-resistant moisture-absorbing material - 3D mesh Bottom material: two-layer foam-based insole, moisture wicking Sole fastening method: molded Normative and technical documentation: TR TS 019/2011 "On the safety of personal protective equipment" Series: TECHNIK Sole: PU / TPU, two-layer Primary color: gray Description The model is made with an anti-puncture set-in Kevlar insole. Kevlar in its structure is a para-aramid fiber (polyparaphenylene terephthalamide). Fibers and threads from the composition of Kevlar have the following characteristics: high tensile strength and tensile strength (cut); low density (30-60 g / sq. meter); strengthening of strength when the temperature drops down to -200 degrees; high elasticity; chemical resistance; low electrical conductivity; resistance to burning and melting; no corrosion; non-toxicity. Genuine velor leather is used in the upper of the shoe. Moisture-wicking 3D mesh is responsible for the microclimate inside the boot. The two-layer sole (PU / TPU) of the injection method of fastening will help reduce the load on the spine, and also has excellent wear resistance. The protective toe cap is made of composite (Mun200). Composite, unlike metal, is not electrically conductive in its structure. The anatomically correct last, in combination with the foam insole, will create comfort when worn. Versatile, lightweight, durable - the best choice for professionals! Production in Klin (Moscow region) according to TR CU 019/2011, GOST 12.4.137-2001, GOST 28507-99, GOST R 12.4.187-97

Hunting shoe covers Jaeger 2101/01 - inexpensive and high-quality equipment for winter trips to the forest, hunting and fishing. The black hem and straps pair well with the camouflage combination upper and hold up well to dirt in the wild. MATERIALS AND TECHNOLOGIES Boot covers made of waterproof DU-Light foam rubber remain elastic at temperatures down to -60ºС and allow you to actively move in driven and running hunting Durable and resistant to abrasion and punctures, the outsole allows you to move through the forest with an abundance of deadwood when tracking down The protector with a multidirectional pattern provides stability on icy snow or slippery roads when moving with a loaded backpack and other hunting equipment EASY TO USE The upper made of waterproof and windproof Oxford 600 material and a removable warm liner with the addition of natural wool keep you warm on the way to the camp or while tracking game Jaeger 2101 shoe covers /01 can also be used for snowmobile trips and other country activities H1-Hunting boot covers Shock-absorbing inserts-No Lettering Clasp-Carabiners, retainer Heel-No Contents-Shoe covers, liner Construction-Sewn Brief description-Great for dry frosty weather. Cuff-Yes Shoe material-EVA (EVA) Du-care Shaft material-Oxford Insulation material-Combined Directions-Fishing Seam treatment-Glued Whitening-Do not bleach Gender-Male Reflective elements-Yes Seasonality-Winter Shelf life, months-12 Wash- Only manual up to 40 Country-Russia Drying-Vertical drying Grip-Aggressive protector Removable insole-Yes Extreme temperature, °С--60 Warm liner-Yes Trademark-DUNA Reinforced heel-No Reinforced toe-Yes Toe shape-Round Dry cleaning-Dry cleaning prohibited Volume per pack. single, cube m.-0.02304 Color-Reed grey/black Main base color-Camouflage Additional base color-Black

(polyparaphenylene-terephthalamide) fiber manufactured by DuPont. Kevlar has high strength (tensile strength σ 0 = 3620 MPa). Kevlar was first obtained by Stephanie Kwolek's group in 1964, the production technology was developed in 1965, and commercial production began in the early 1970s.

Application

Initially, the material was developed for reinforcing car tires, for which it is still used. In addition, Kevlar is used as a reinforcing fiber in composite materials, which are strong and lightweight.

Kevlar fiber is also used as a reinforcing component in mixed fabrics, giving products from them resistance to abrasive and cutting effects, such fabrics are used, in particular, for protective gloves and protective inserts in sportswear (for motorsports, snowboarding, etc.) .). It is also used in the shoe industry for the manufacture of anti-puncture insoles.

Means of individual armor protection

The mechanical properties of the material make it suitable for the manufacture of personal armor protection (NIB) - bulletproof vests and armored helmets. Studies of the second half of the 1970s showed that Kevlar-29 fiber and its subsequent modifications, when used in the form of multilayer fabric and plastic (fabric-polymer) barriers, show the best combination of energy absorption rate and duration of interaction with the impactor, thereby providing relatively high, at a given mass of obstacles, indicators of bulletproof and anti-fragmentation resistance. This is one of the most famous uses of Kevlar.

In the 1970s, one of the most significant developments in the development of body armor was the use of Kevlar reinforcing fiber. Development of a body armor made of Kevlar by the US National Institute of Justice (eng. National Institute of Justice) took place over several years in four stages. The first step was to test the fiber to see if it could stop a bullet. The second phase was to determine the number of layers of material needed to prevent penetration by bullets of different calibers and speeds, and to develop a prototype vest capable of protecting employees from the most common threats: .38 Special and .22 Long Rifle bullets. By 1973, a seven-layer Kevlar fiber vest had been developed for field testing. It was found that when wet, the protective properties of Kevlar deteriorated. The ability to protect against bullets also decreased after exposure to ultraviolet light, including sunlight. Dry cleaning and bleaching also took a toll on the protective properties of the fabric, as did repeated washes. To circumvent these problems, a water-resistant vest has been developed that is coated with fabric to prevent exposure to sunlight and other negative factors.

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Notes

Literature and sources

O. Lisov. "Kevlar - a promising military material" // "Foreign military review", No. 2, 1986. pp. 89-90.

Natural
(natural)



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artificial

Synthetic

Inorganic

An excerpt characterizing Kevlar

“Take, take the child,” Pierre said, giving the girl and imperiously and hastily addressing the woman. Give them back, give them back! he almost shouted at the woman, putting the screaming girl on the ground, and again looked back at the French and the Armenian family. The old man was already sitting barefoot. The little Frenchman took off his last boot and patted his boots one against the other. The old man, sobbing, said something, but Pierre only glimpsed it; all his attention was directed to the Frenchman in the hood, who at that moment, slowly swaying, moved towards the young woman and, taking his hands out of his pockets, took hold of her neck.
The beautiful Armenian woman continued to sit in the same motionless position, with her long eyelashes lowered, and as if she did not see and did not feel what the soldier was doing to her.
While Pierre ran those few steps that separated him from the French, a long marauder in a hood was already tearing the necklace that was on her from the neck of the Armenian woman, and the young woman, clutching her neck with her hands, screamed in a piercing voice.
– Laissez cette femme! [Leave this woman!] Pierre croaked in a frantic voice, grabbing a long, round-shouldered soldier by the shoulders and throwing him away. The soldier fell, got up and ran away. But his comrade, throwing down his boots, took out a cleaver and menacingly advanced on Pierre.
Voyons, pas de betises! [Oh well! Don't be stupid!] he shouted.
Pierre was in that ecstasy of fury in which he did not remember anything and in which his strength increased tenfold. He lunged at the barefoot Frenchman, and before he could draw his cleaver, he had already knocked him down and pounded him with his fists. Approving shouts of approval were heard from the surrounding crowd, at the same time, a horse patrol of French lancers appeared around the corner. The lancers rode up to Pierre and the Frenchman at a trot and surrounded them. Pierre did not remember anything from what happened next. He remembered that he was beating someone, he was being beaten, and that in the end he felt that his hands were tied, that a crowd of French soldiers were standing around him and searching his dress.
- Il a un poignard, lieutenant, [Lieutenant, he has a dagger,] - were the first words that Pierre understood.
Ah, une arme! [Ah, weapons!] - said the officer and turned to the barefoot soldier who was taken with Pierre.
- C "est bon, vous direz tout cela au conseil de guerre, [Okay, okay, you'll tell everything in court,] - said the officer. And then he turned to Pierre: - Parlez vous francais vous? [Do you speak French? ]
Pierre looked around him with bloodshot eyes and did not answer. Probably, his face seemed very scary, because the officer said something in a whisper, and four more lancers separated from the team and stood on both sides of Pierre.
Parlez vous francais? the officer repeated the question to him, keeping away from him. - Faites venir l "interprete. [Call an interpreter.] - A little man in a civilian Russian dress rode out from behind the rows. Pierre, by his attire and his speech, immediately recognized him as a Frenchman from one of the Moscow shops.
- Il n "a pas l" air d "un homme du peuple, [He does not look like a commoner,] - said the translator, looking at Pierre.
– Oh, oh! ca m "a bien l" air d "un des incendiaires," the officer smeared. "Demandez lui ce qu" il est? [Oh oh! he looks a lot like an arsonist. Ask him who he is?] he added.
- Who are you? the translator asked. “You should be answered by the authorities,” he said.
- Je ne vous dirai pas qui je suis. Je suis votre prisoner. Emmenez moi, [I won't tell you who I am. I am your prisoner. Take me away,] Pierre suddenly said in French.
- Ah, Ah! said the officer, frowning. — Marchons!
A crowd had gathered around the lancers. Closest to Pierre was a pockmarked woman with a girl; when the detour started, she moved forward.
"Where are they taking you, my dear?" - she said. - The girl, then where will I put the girl, if she is not theirs! - said the grandmother.
- Qu "est ce qu" elle veut cette femme? [What does she want?] the officer asked.
Pierre was like a drunk. His rapturous state was further intensified at the sight of the girl whom he had saved.
“Ce qu" elle dit? - he said. - Elle m "apporte ma fille que je viens de sauver des flammes," he said. – Adieu! [What does she want? She is carrying my daughter, whom I rescued from the fire. Farewell!] - and he, not knowing himself how this aimless lie escaped from him, with a decisive, solemn step, went between the French.
The French patrol was one of those that were sent by order of Duronel through various streets of Moscow to suppress looting and especially to catch arsonists, who, according to the general opinion that appeared that day among the French of higher ranks, were the cause of fires. Having traveled around several streets, the patrol took another five suspicious Russians, one shopkeeper, two seminarians, a peasant and a courtyard man, and several marauders. But of all the suspicious people, Pierre seemed the most suspicious of all. When they were all brought to spend the night in a large house on Zubovsky Val, in which a guardhouse was established, Pierre was placed separately under a strict guard.

At that time in St. Petersburg, in the highest circles, with more fervor than ever before, there was a complex struggle between the parties of Rumyantsev, the French, Maria Feodorovna, the Tsarevich and others, drowned out, as always, by the trumpeting of court drones. But calm, luxurious, preoccupied only with ghosts, reflections of life, Petersburg life went on as before; and because of the course of this life, great efforts had to be made to realize the danger and the difficult situation in which the Russian people found themselves. There were the same exits, balls, the same French theater, the same interests of the courts, the same interests of service and intrigue. It was only in the highest circles that efforts were made to recall the difficulty of the present situation. It was told in a whisper about how opposite one another acted, in such difficult circumstances, both empresses. Empress Maria Feodorovna, concerned about the well-being of the charitable and educational institutions subordinate to her, made an order to send all the institutions to Kazan, and the things of these institutions had already been packed. The Empress Elizaveta Alekseevna, when asked what orders she wanted to make, with her usual Russian patriotism deigned to answer that she could not make orders about state institutions, since this concerned the sovereign; about the same thing that personally depends on her, she deigned to say that she would be the last to leave Petersburg.

Each generation living in a particular time period has its own rules and principles, requirements for mobility and quality of life. Accordingly, the acceleration of scientific and technological progress in all sectors is followed by an increase in the overall pace, and the new time dictates its own rules. So a kind of fashion for things with the inclusion of Kevlar threads has affected not only specialized units, including the military, but also ordinary people who value their safety and love comfort.

Kevlar: what is it?

Strong Kevlar fibers have long been woven into the structure of developments in the automotive, construction, military industries, partially replacing less durable and practical steel. The material "woven" from organic threads has become simply indispensable due to its unique characteristics. So, now let's take a closer look at the question of Kevlar - what it is, and find out the history of its appearance.

Briefly about the origin

The new polymer, in a sense, became the "child" of His Majesty Chance, having been born in the laboratories of the Dupont company, which already at that time had to its credit the invention of such a material as nylon. Then, in 1964, a research group was looking for a solution to replace the steel cord in car tires with much lighter polymer threads, such as polyaramid. Accordingly, the lesson was not an easy one, since polyaramids must first be dissolved (which in itself is not an easy task), and only then “spin” threads from the resulting mass. A positive result was achieved by Stephanie Kwolek. She managed to obtain fibers of exceptional strength, which, after testing, showed stunning results - the new thread was stronger than steel.

But this was only the beginning of the brilliant history of this material. Kevlar fabric appeared on the market in 1975, and since that time there has been no need to complain about the lack of demand. And he gives birth to production, so Dupont does not stop there. The company is making significant financial investments to upgrade the patented Kevlar material with improved performance.

Status for today

Now let's move on to our time. Modern Kevlar - what is it? And this is a surprisingly light and soft material that does not burn in fire and even almost does not smolder, perfectly absorbs moisture, allowing the skin to "breathe", and at the same time surpasses steel in strength by several times, withstanding a tensile load of 2500 N Yes, and the processing of fabric is quite easy and does not require narrow-profile equipment.

How to produce

Fiber-forming polymers are produced at low temperature by solution polycondensation. The reagents are added to the latter and intensively mixed. From this solution, the polymer is released in the form of chips or gel. Then it is washed and dried. Then the polymer is dissolved in strong acids (for example, sulfuric). Threads and fibers are formed from the resulting solution by extrusion. They are washed and dried.

Kevlar fibers are a crystallizing polymer. Their structure is characterized by a high degree of rigidity. This is due to the presence of benzene rings. By structure, Kevlar refers to network polymers. It is produced in the form of technical threads with different linear density and structure. The number of fibers in the threads can be different: from 130 to 1000 in the production of Kevlar fabric and from 500 to 10 thousand in the manufacture of cord and ropes. This material is available in the form of roving, fabric and yarn. The fibers are opaque, their average diameter is 11 microns.

Applications

Kevlar finds its application in industries where wear resistance and thermal stability, low structural rigidity and maximum lightness, as well as excellent strength at low weight, are extremely important. Therefore, it is not surprising that this material came "to the court" in the manufacture of personal protective equipment, in particular bulletproof vests, helmets.

Kevlar: defending in comfort

To date, various Kevlar clothing is being made, designed not only for military personnel and various special forces, but also for those who choose an ultra-active lifestyle and are obsessed with the same hunting or airsoft. Of course, an airsoft player does not need Kevlar armor with a high level of protection and additional armor plates, but a T-shirt with special Kevlar inserts will be very appropriate. In addition, such elements are easy to hide under outerwear, and models suitable for design have been developed.

Perhaps the most popular products from Kevlar can be considered armored helmets, and, of course, bulletproof vests. By the way, it is from this fabric that the means of passive protection adopted by NATO are made.

Hand protection

Tactical gloves with Kevlar in the form of protective inserts on the palms and knuckles allow not only to protect the hand from damage in a collision, for example, with the teeth of the enemy, but also to significantly increase the blow, making it crushing. Such a peculiar modern analogue of brass knuckles. Given the strength, warmth and resistance to moisture and damage, such accessories have recently become popular not only among employees of specialized units, but also among extreme sportsmen, street fighters, and lovers of an active lifestyle. They are also in demand among those for whom the dark streets of their native settlement cause well-founded fears.

And a bullet, and a bayonet ... will Kevlar stop?

Kevlar body armor is considered to be one of the most reliable means of personal passive protection. Due to its unique lightness, strength and relative durability, such "armor" is able to protect the wearer from the sliding blows of edged weapons and mitigate the effects of bullets, preventing the penetration and spread of fragments.

When choosing a body armor based on this polymer, you should take into account some of the nuances with which it is endowed. Kevlar - what is it? Soft armor, which will not save you from a point-blank shot or a penetrating blow with a knife or awl, therefore, models with special hard panels designed to additionally absorb the blow have been developed.

Everyone has their cons

The disadvantages of Kevlar include light sensitivity - with prolonged exposure to sunlight, the miracle material begins to break down, albeit very, very slowly. The best means of protection was the sewing of elements with Kevlar threads into a denser fabric.

The price of products with paraamide threads is quite high, and this is what prevents the general "Kevlarization". Only economically developed countries can afford to equip the army with tactical products from this material.

In conclusion

To date, it is extremely difficult to imagine passive protection without Kevlar fibers, and bulletproof vests made from such fabric have saved many lives. Therefore, the creators have something to be proud of. And manufacturers need to expand the production of Kevlar and constantly improve its quality characteristics.

Kevlar fiber has a characteristic golden yellow color. The diameter of an elementary fiber is 10 µm.

Kevlar K-29 (1975) - used in industry for the manufacture of cables, brake pads, personal armor and armor of combat vehicles. Kevlar K49 is a brand of high-modulus fiber used in the cable industry, for the manufacture of fiber optic braid, for the manufacture of ropes, and for plastic reinforcement. Kevlar K100 is manufacturer dyed yarn. Kevlar K119 - High elongation, flexible and high fatigue strength. Kevlar K129 is a high strength fiber grade for armor. Kevlar AP - 15 percent more durable than K-29. Kevlar XP is a compound based on a high viscosity resin and the new KM2plus fibre. Kevlar KM2(1992) - brand of fiber for obtaining fabric that meets the requirements for armored helmets and bulletproof vests.

Application

Initially, the material was developed for reinforcing car tires, for which it is still used to this day. In addition, Kevlar is used as a reinforcing fiber in composite materials, which are strong and lightweight.

Means of individual armor protection

Fragments of a Kevlar fabric-polymer helmet used in combat to absorb the energy of a hand grenade explosion, northeastern Iraq, 2004. Squad personnel rescued, Corporal Dunham, who covered the grenade with his helmet, died.

The mechanical properties of the material make it suitable for the manufacture of personal armor protection (NIB) - bulletproof vests and armored helmets. Research in the second half of the 1970s showed that Kevlar-29 fiber and its subsequent modifications, when used in the form of multilayer fabric and plastic (fabric-polymer) barriers, provide the best combination of energy absorption rate and duration of interaction with the impactor, thereby providing relatively high, at a given mass of obstacles, indicators of bulletproof and anti-fragmentation resistance. This is one of the most famous uses of Kevlar.

Kevlar has a relatively low weight, with a significant force of internal friction, which allows you to quickly dissipate kinetic energy in a collision, turning it into heat. At the same time, due to its thinness, it is not able to stop sharp and heavy objects with high momentum, for example, a rifle bullet or a bayonet blade. For this reason, in modern army bulletproof vests, it is combined with additional protective plates made of steel, titanium or ceramics, which are short-lived, but can save the life of a soldier in battle, as well as with shock-absorbing elements to reduce the armored effects of shells.

In the 1970s, one of the most significant developments in the development of body armor was the use of Kevlar reinforcing fiber. The development of a Kevlar body armor by the US National Institute of Justice took place over several years in four stages. The first step was to test the fiber to see if it could stop a bullet. The second phase was to determine the number of layers of material needed to prevent penetration by bullets of different calibers and speeds, and to develop a prototype vest capable of protecting employees from the most common threats: .38 Special and .22 Long Rifle bullets. By 1973, a seven-layer Kevlar fiber vest had been developed for field testing. It was found that when wet, the protective properties of Kevlar deteriorated. The ability to protect against bullets also decreased after exposure to ultraviolet light, including sunlight. Dry cleaning and bleaching also took a toll on the protective properties of the fabric, as did repeated washes. To circumvent these problems, a water-resistant vest has been developed that is coated with fabric to prevent exposure to sunlight and other negative factors.