Method of manufacturing structures intended for layers of packets reducing ballistic injuries

Description of the invention

The subject of the invention is a method of producing structures intended for layers of packages reducing ballistic injuries.

The main goal of research on bulletproof vests is to develop a cheap, light, comfortable protective system with resistance to ballistic impacts. However, the standards of bulletproof vests differ depending on the country - the basic requirement is always stopping the bullet and low body trauma resulting from the transverse deformation of the ballistic package. This deformation value measured on a calibrated plasticine substrate can range from 25 mm to 44 mm depending on the standards of the protective system. If the penetration depth exceeds this value, the user may suffer serious, even fatal, injury.

Commonly used textile products for the layers of ballistic packages are biaxial fabrics with various weaves, with a dominant plain weave, nonwovens, multiaxial fabrics, mainly triaxial, and unidirectional UD (UniDirectional) laminates composed of two or four layers with an orientation of 0/90 or 0/90, respectively. /0/90, each of which consists of parallel arranged high-strength fibers separated by a thermoplastic matrix and welded. UD laminates, compared to fabrics, can ensure less lateral deformation of the ballistic package and thus a smaller scale of body injuries during bullet impact, while maintaining the same ballistic effectiveness.

Methods for producing unidirectional fiber laminates are described in US Patent Nos. 4916000, 4748064, 4737401, 4681792, 4650710, 4623574, 4563392, 4543286, 501854, 4457985 and 4403012. Commonly used materials ami in these structures is para-aramid with the trade name Kevlar and Twaron and very high molecular weight polyethylene with the trade names Dyneema and Spectra.

These materials are used to produce fibers characterized by low density, high strength and high energy absorption, which constitute the base material for the production of high-strength yarns, fabrics, nonwovens and UD laminated products.

To meet the requirements for protection against typical ballistic threats, i.e. stopping the bullet and transverse deformation of the package below the permissible standards, approximately 20-50 layers of these products are required, depending on the type of flat structures and material used. A larger number of layers reduces transverse deformation, but the resulting armor becomes heavy and may not meet the requirements regarding the comfort of use of the product.

There are also known methods of producing textile light ballistic packages, which involve modifying the structure of the packages to reduce the lateral deformation of the ballistic package and the scale of injuries suffered by a person after being hit by a projectile. The most well-known method of producing these packages is to use a combination of high-strength materials that absorb the energy of the bullet's impact and materials that reduce injuries. In this way, multi-layer hybrid systems are created, containing programmatically assembled layers of high-strength flat textile products, such as fabrics, UD laminates, nonwovens, and layers of materials that reduce injuries, such as spacer knitted fabrics, foams of various thicknesses, cellular structures, for example, of the "honeycomb" type. ", needle-punched nonwoven inserts.

Patent No. US 4,413,357 proposes a combination of a multi-layer ballistic package containing aramid fiber fabrics with at least one layer of flexible polycarbonate sheet and a layer of soft, thick, foam plastic (on the front and back or on the back of the panel).

The description of patent application No. EP 0131447A2 proposes making an injury-reducing layer by placing feathers, foam or felt between two aramid fabrics and sewing the whole thing.

From the description of patent application No. EP 172415A, a ballistic package is known consisting of a number of layers of high-strength fabric and a shock absorber with a three-dimensional structure with a waffle-like structural surface.

The patent application no. WO 9624816A1 describes the combination of a shock-absorbing system in the form of 10 mm thick elastic foam with layers of fabric made of high-strength fibers.

In the description of patent application No. CA 2169415 A, it is proposed to create a package that reduces ballistic injuries by assembling two packages made of high-strength materials placed one on top of the other, between which a layer of material with reduced density is placed to maintain an air gap while the user is wearing the protective system.

As a layer reducing the effects of trauma during a bullet impact, patent description US 6103641 also proposes a special spacer knitted fabric consisting of a front and rear top layer, connected and held at a distance of 12-30 mm from each other by means of strings.

The description of patent application No. US 20030008584 A1 discloses a method of producing a needled nonwoven fabric with a programmed fiber orientation, ensuring a cushioning effect.

Reduced body injuries due to ballistic impact can also be achieved by modifying the structure of high-strength flat textile products. It concerns the method of arranging fibers and threads in the structure as well as covering flat, high-strength textile products with various resin compositions and compositions containing nanoparticles.

Teijin Aramid (The Netherlands) produces a high-strength Twaron® LFT AT/AT Flex hybrid structure in which the Twaron® CT 707 para-aramid fabric is combined with the Curv® elastic composite (produced by Propex Fabrics) with reinforcement in the form of polypropylene fibers. A multi-layer ballistic package made of these structures is able to reduce transverse deformation during bullet impact by 30-60% compared to the CT 707 fabric alone with a slight increase in surface weight.

In the description of patent application No. US 20130090029 A1, in order to increase ballistic effectiveness, it is proposed to use a repeating hybrid system of two or three fabrics arranged one behind the other, differing in the weave and the linear mass of high-strength yarn. These layers can be connected to each other using seams, laminating foil or resin.

The use of triaxial braided products is also known from the description of patent application No. US 20130055882 A1. It was found that the participation of such layers in the ballistic package contributes to reducing the transverse deformation of the package during bullet impact.

Similar conclusions are contained in the DOI article: https://doi.org/10.2478/aut-2020-0015, which compared the ballistic effectiveness of biaxial and triaxial fabrics with comparable surface mass, made of the same Kevlar 29 yarn. The aim of the invention is to develop a method enabling the production of layers of packages that effectively reduce the effects of ballistic trauma in the human body, with programmatically formed strength properties.

The method of producing structures intended for layers of packages reducing ballistic injuries, from woven, knitted fabrics, laminates or non-woven fabrics made of high-strength yarn, according to the invention is characterized by the fact that the substrate in the form of a fabric, knitted fabric, laminate or non-woven fabric intended for layers of packages reducing ballistic injuries at least two straight strands of threads with an average linear weight of 500-4000 dtex are embroidered, each of which contains at least 50 threads/dm, placed one on top of the other at an angle of 5-90° to each other, using threads with a strength exceeding 500 cN and at the same time with a linear weight below 100 dtex, preferably with a cross stitch. The substrate is preferably made of para-aramid yarn or a UD laminate made of HPPE (High Performance PolyEthylene) fibers, the strands are preferably embroidered from para-aramid or HPP polyethylene yarn, and polyester silk thread is preferably used as the embroidery thread. Embroidering thread strands is done using an embroidery machine controlled by a computer program.

The layers produced in this way are composed of ballistic injury-reducing packages containing at least 10 of these layers, depending on the bulletproof class of the package, or these layers are placed in a hybrid package between unembroidered layers of fabrics, laminates or non-woven fabrics made of high-strength fibers intended for ballistic injury-reducing packages. .

Packages reducing ballistic injuries made from structures made according to the invention or with the use of these structures are high-strength, light, soft and comfortable to wear. Straightened threads in the structure of the layers produced according to the invention enable a faster transfer of stresses during a bullet impact compared to the speed of stress propagation in a structure containing interlaced threads, and the energy of the bullet impact covers a larger surface of the layers in the ballistic package, which favors smaller transverse deformation of the ballistic package.

The following examples illustrate the subject of the invention.

EXAMPLE I

Using a dedicated computer program for the JCZA 0109-550 embroidery machine (ZSK Stickmaschinen, Germany), a computer pattern for the arrangement of high-strength yarn was designed as two 20 cm x 20 cm strands embroidered to the ground, one on top of the other, at an angle of 90°. The programmed thread count in both bands was 105 threads/dm. The developed computer pattern was then transferred to the JCZA 0109-550 embroidery machine and then para-aramid yarn Twaron 930 dtex - Type 2040 (Teijin Aramid, the Netherlands) was wound on the feed roll of this embroidery machine, and TYTAN 360 polyester silk thread (Ariadna, Poland) with an average linear weight of 85 dtex. A substrate in the form of spun-bonded polypropylene nonwoven fabric with a surface weight of 80 g/m was placed on the computer-controlled XY table of the embroidery machine.². After starting the embroidery machine, two strands of para-aramid yarn were embroidered to the base, where the first set of threads was attached with cross embroidery to the non-woven base, while the second set of threads was attached in a similar way to the first set of threads at an angle of 90°.

Proceeding in this way, 26 identical structures were made and then assembled into one ballistic package.

The obtained ballistic package was then placed on a calibrated plasticine substrate in accordance with NIJ Standard-0101.06 and one shot was fired into the center of the package with a 9x19 mm Parabellum bullet at a speed of 381 ± 3 m/s. After removing the ballistic package, the resulting deformation of the plasticine substrate was scanned using a 3D scanner and the maximum deformation of the substrate was read, which was 25.9 mm.

For comparison purposes, a ballistic package was made consisting of 26 typical layers used in soft ballistic packages made of Twaron CT709 Microfilament 930 para-aramid fabrics (Teijin Aramid, the Netherlands), made of the same yarn as the embroidered structure and with the same thread count and surface weight. . The package prepared in this way was then placed on a calibrated plasticine substrate in accordance with the NIJ Standard-0101.06 standard and one shot was fired into the center of the package with a 9x19 mm Parabellum bullet at a speed of 381 ± 3 m/s. After removing the ballistic package, the resulting deformation of the plasticine substrate was scanned using a 3D scanner and the maximum deformation of the substrate was read, which was 30.2 mm. This meant that the deformation of the package made of embroidered structures was 14.2% lower than the deformation of the package made of unembroidered layers of yarn the same as the embroidered layers.

EXAMPLE II

Proceeding as in example I, 13 embroidered layers were made. Then, 13 layers measuring 20 cm x 20 cm were cut from Twaron CT709 Microfilament 930 fabric (Teijin Aramid, The Netherlands). The whole thing was assembled into a hybrid ballistic package in such a way that 13 layers of fabric were placed on the side of the bullet impact, and 13 embroidered layers were placed on the opposite side of the package. The package prepared in this way was then placed on a calibrated plasticine substrate in accordance with the NIJ Standard-0101.06 standard and one shot was fired into the center of the package with a 9x19 mm Parabellum bullet at a speed of 381 ± 3 m/s. After removing the ballistic package, the resulting deformation of the plasticine substrate was scanned using a 3D scanner and the maximum deformation of the substrate was read, which was 22.6 mm.

This meant that the deformation of the package prepared from embroidered layers was 20.9% lower than the deformation of the package composed of 26 layers of unembroidered Twaron CT709 Microfilament 930 fabrics.

EXAMPLE III

Proceeding as in example I, 13 embroidered layers were made, with the difference that instead of polypropylene non-woven fabric, Twaron CT709 Microfilament 930 para-aramid fabric (Teijin Aramid, the Netherlands) was used as the base. The whole thing was assembled into a hybrid ballistic package, which was placed on a calibrated plasticine substrate in accordance with the NIJ Standard-0101.06 standard, and one shot was fired into the center of the package with a 9x19 mm Parabellum bullet at a speed of 381 ± 3 m/s. After removing the ballistic package, the resulting deformation of the plasticine substrate was scanned using a 3D scanner and the maximum deformation of the substrate was read, which was 23.9 mm.

This meant that the deformation of the package prepared from embroidered layers was 25.2% lower than the deformation of the package composed of 26 unembroidered layers of Twaron CT709 Microfilament 930 fabrics.

Example IV

Using a dedicated computer program for the JCZA 0109-550 embroidery machine (ZSK Stickmaschinen, Germany), a computer pattern of triaxial arrangement of high-strength yarn was designed as three strands of dimensions 20 cm x 20 cm, embroidered to the ground one on top of the other at angles of -60°/0°/60, respectively. °. The programmed thread count in both bands was 105 threads/dm. The developed computer pattern was then transferred to the JCZA 0109-550 embroidery machine and then, using the same materials as in example I, 18 identical structures were made, which were then assembled into one ballistic package.

The obtained ballistic package was then placed on a calibrated plasticine substrate in accordance with NIJ Standard-0101.06 and one shot was fired into the center of the package with a 9x19 mm Parabellum bullet at a speed of 381 ± 3 m/s. After removing the ballistic package, the resulting deformation of the plasticine substrate was scanned using a 3D scanner and the maximum deformation of the substrate was read, which was 23.7 mm.

For comparison purposes, a ballistic package consisting of 27 unembroidered layers of Twaron CT709 Microfilament 930 para-aramid fabric was made, thus maintaining a comparable surface mass of the package in relation to the package composed of embroidered triaxial structures. The package prepared in this way was then placed on a calibrated plasticine substrate in accordance with the NIJ Standard-0101.06 standard and one shot was fired into the center of the package with a 9x19 mm Parabellum bullet at a speed of 381 ± 3 m/s. After removing the ballistic package, the resulting deformation of the plasticine substrate was scanned using a 3D scanner and the maximum deformation of the substrate was read, which was 29.4 mm.

This meant that the deformation of the package composed of embroidered layers was 19.4% lower than the deformation of the package composed of unembroidered layers while maintaining comparable masses of high-strength yarn in both packages.