The prototype of human armor dates back to ancient times, and the primitive nation used natural fiber braided tape as a chest protection material to prevent physical injury. The development of weapons forces human armor to make corresponding progress.
As early as the late 19th century, silk used in Japanese medieval armor was also used in bulletproof clothing made in the United States. In 1901, after the assassination of President William McKinley, the body armor caught the attention of the United States Congress. Although the body armor protects against low-speed pistol bullets (at 122 m/s), it does not protect against rifle bullets. Thus, during the First World War, natural fiber fabrics appeared as clothing lining, with steel plate made of bulletproof clothing. Thick silk garments were once a major part of bulletproof vests.
However, the rapid deterioration of silk in the trenches, this defect, coupled with the limited ability to prevent bullet scars and the high cost of silk, made the silk body armor in the First World War by the United States Department of Ordnance snubbing, failed to popularize. During the Second World War, shrapnel was killed by 80 per cent, and 70 per cent of the wounded died as a result of injuries to the torso. The participating countries, especially britain and the United States, began to spare no effort in developing body armor. In October 1942, the British army first developed a bulletproof vest consisting of three high-manganese steel plates. In 1943, there were 23 types of body armor in the United States. Bulletproof clothing during this period was made of special steel as the main bulletproof material. In June 1945, the U.S. military developed a bulletproof vest with a combination of aluminum alloy and high-strength nylon, modelM12 infantry body armor. The nylon 66 (known polyamide 66 fiber) was the synthetic fiber invented at that time, its fracture strength (gf/d: krypton) is 5.9 to 9.5, the initial module (gf/d) is 21 to 58, the specific gravity is 1.14 g / (cm) 3, its strength is almost twice that of cotton fiber.
During the Korean War, the U.S. Army was equipped with T52 all-nylon body armor made of 12 layers of bulletproof nylon, while the Marine Corps was equipped with the M1951 hard "Dolon" fiberglass bulletproof vest, which weighed between 2.7 and 3.6 kg.
Nylon-based body armor provides a certain level of protection for soldiers, but is larger and weighs up to 6 kg. In the early 1970s, Kevlar, a synthetic fiber with ultra-high strength, ultra-high modulus and high temperature resistance, was developed by DuPont in the UNITED States and quickly developed in the field of bulletproof. The emergence of this high-performance fiber has greatly improved the performance of soft textile body armor, but also greatly improved the comfort of the body armor. The U.S. military pioneered the use of Kevlar to make body armor, and developed two models of light and heavy. The new body armor is made of Kevlar fabric and capped with bulletproof nylon cloth.
The lightweight body armor consists of 6 layers of Kevlar fabric with a medium weight of 3.83 kg. With the commercialization of Kevlar, Kevlar's excellent comprehensive performance makes it soon widely used in the bulletproof vests of national armies. Kevlar's success and the subsequent emergence of Twaron and Spectra and their use in body armor led to the popularity of soft body armor, characterized by high-performance textile fibers, which has been extended beyond the military community to the police and political arenas. However, pure soft body armor is still incompetent for high-speed bullets, especially those fired from rifles. To this end, people have developed a soft and hard composite body armor, fiber composite materials as an enhanced panel or insert plate, in order to improve the overall bulletproof body armor. To sum up, the development of modern bulletproof clothing has appeared three generations: the first generation for the hard body armor, mainly with special steel, aluminum alloy and other metals as bulletproof materials.
This type of bulletproof clothing is characterized by: clothing thick, usually about 20 kg, wearing uncomfortable, the human body movement restrictions are greater, with a certain bulletproof performance, but easy to produce secondary breaks. The second generation of body armor is a soft body armor, usually made from high-performance fabrics such as multi-layered Kevlar. Its light weight, usually only 2 to 3 kg, and the texture is more soft, fit, wear ingress edgy is also more comfortable, wearing with better concealment, especially suitable for police and security personnel or political officials wear ingenuity. In the bullet-proof ability, generally can protect 5 meters away from the pistol shot, will not produce secondary shrapnel, but after being hit by the bullet deformation is larger, can cause a certain non-penetration damage. In addition, for rifles or machine-gun bullets, the general thickness of the soft body armor is difficult to resist. The third generation of body armor is a composite body armor.
Usually with lightweight ceramic sheet as the outer layer, Kevlar and other high-performance fabrics as the inner layer, is the main development direction of bulletproof clothing. India's MKU company's latest development of a new type of body armor (Instavest), claimed to be the world's fastest wearing, the fastest bulletproof body armor. The highlight of this body armor is its ability to wear and take off quickly. It is specially designed with a quick pull ring, which can be easily removed by pulling the entire body armor. According to reports, take off the body armor only 1 second, wear this body armor takes 45 seconds.