WO2020035502A1

WO2020035502A1 - Multilayer ballistic protection panel

Info

Publication number: WO2020035502A1
Application number: PCT/EP2019/071742
Authority: WO
Inventors: Michel Baikrich
Original assignee: Michel Baikrich
Priority date: 2018-08-13
Filing date: 2019-08-13
Publication date: 2020-02-20
Also published as: EP3837487B1; EP3837487B8; MX2021001049A; EP3838586A1; PT3837487T; EP3837487A1; PL3837487T3; WO2020035096A1; BR112021001640A2; ZA202100318B

Abstract

The invention relates to a multilayer ballistic protection panel (1) which comprises a stack of layers of fabric (2) woven with twisted polyester threads and layers of adhesive (3) made of polyethylene-based thermoplastic material (8) which are alternately interposed between the layers of fabric. The overall cohesion of the panel is ensured by the thermoplastic material that passes through the interstices (7) of the layers of fabric and links the adhesive layers together. The panel is preferably a compact laminated panel manufactured by hot pressing under high pressure. It can be used alone or in combination with steel or ceramic to produce bulletproof clothing and accessories and coatings for the walls of civilian or military vehicles or for armoured construction elements.

Description

MULTI-LAYER BALLISTIC PROTECTION PANEL

Technical area

The present invention belongs to the technical field of ballistic protection and structural reinforcement materials in the face of various threats with high kinetic energy, impacting on a very small surface.

It relates more particularly to a compact panel comprising a superposition of layers of fabric woven from twisted polyester threads, between which are alternately interleaved layers (films) of polyethylene-based thermoplastic adhesive which ensure the cohesion of the assembly , thanks to an interpenetration, at the time of its melting point, by increasing the pressure of the press of progressive shape, of the thermoplastic adhesive between the meshes of the layers of polyester fabrics.

The panel according to the invention can be advantageously used for individual ballistic protection, in particular in bulletproof vests and EOD suits (also reducing trauma "Deformation") or bulletproof accessories, but also collective in fixed or mobile installations , in particular for civil or military vehicles, or building or furniture elements.

Prior art

Nowadays, there are many technical solutions for individual or collective ballistic protection. These generally use high-tech materials and are very expensive to obtain a high level of performance and lightness.

These materials are mainly made from mineral or synthetic fibers with very high mechanical performance and in particular from type S glass fibers, Para-aramid / Meta-aramid fibers or very high molecular weight polyethylene fibers (UHMPE). or UHMWPE for "Ultra High Molecular Weight Polyethylene" in English).

Materials made from glass fibers offer limited mechanical and ballistic protection performance compared to those obtained using specific synthetic fibers. They are therefore used for relatively small applications.

Those obtained from very high molecular weight polyethylene fibers, such as SPECTRA ™ fibers sold by the company Honeywell or DYNEEMA ™ sold by the company DSM, are extremely expensive because of the very high price of the raw material and the difficult control of the manufacturing processes. They are therefore reserved for limited applications with high added value and for applications in which lightness is vital, such as for example in fixed wing or gyratory aircraft.

As a result, the materials produced on the basis of para-aramid and meta-aramid fibers, such as for example KEVLAR ™ sold by the company Dupont or TWARON ™ by the company Teijin, are currently the most used for producing materials of ballistic protection intended, inter alia, for protective clothing (vests and bullet-proof jackets) or for the shielding of civil or military vehicles.

However, even if their cost price is slightly lower than that of very high molecular weight polyethylene-based materials, they remain expensive and the purchase of large area panels, for example for the shielding of a military vehicle, is very expensive. In addition, there are often very long supply times for obtaining such fibers.

Furthermore, even if the aramid-based materials are technically efficient, they have many disadvantages.

In fact, they are very sensitive to environmental conditions (UV, humidity, decay and aging in general), which quickly compromises their mechanical properties and their effectiveness. They therefore have a very low durability which requires frequent replacement, even if we use specific binding protective coatings (encapsulations).

To guarantee the effectiveness of ballistic protection, it is thus recommended for military operational vehicles, to replace every year the internal coating of military vehicles, when it is made with this type of material. Due to the high price of these materials, such replacement, with the immobilization of the vehicle, represents a particularly significant financial cost over the lifetime of these vehicles.

In addition, due to the use of synthetic thermosetting raw materials, these materials are neither repairable nor recyclable.

In addition, these materials, comprising phenolic or epoxy resins, give off very toxic compounds in the event of combustion.

For all these reasons, the current technical solutions are not satisfactory and a new solution is long overdue. Statement of the invention

The objective of the invention is to overcome the drawbacks of these materials of the prior art and to provide a ballistic protection material which is both efficient and also economical.

For this, the invention teaches a multilayer ballistic protection panel comprising a superposition of layers of fabric of woven threads, the weaving leaving free through gaps between the threads in each layer of fabric, and layers of adhesive which are interposed in alternation between the layers of fabric and which ensure the overall cohesion of the panel.

According to the invention, the layers of woven yarn fabric include layers of woven fabric with twisted polyester yarns, and the adhesive layers are layers of a polyethylene-based thermoplastic material.

Advantageously, the adhesive layers are layers of a thermoplastic material based on polyethylene LLDPE - LDPE - HDPE.

In addition, the thermoplastic material passes through the interstices of the fabric layers and connects the adhesive layers with each other, thereby ensuring the overall cohesion of the panel.

According to one embodiment, the multilayer ballistic protection panel is a compact laminated panel produced by hot pressing under high pressure, to circulate the adhesive in fusion between each mesh of the layers of fabric.

As PE does not stick with anything, then we stick it with itself using the principle of thermofusion to thus stick the layers of fabric.

According to the variants, the fabric of the layers of fabric woven with twisted polyester threads can be woven in a flat or braided weaving pattern.

According to one embodiment, the polyester yarns used are twisted Z or S, more preferably twisted Z, with 40 to 80 twists per meter of yarn and preferably about 60 twists per meter of yarn.

By definition, twisted wires Z are twisted clockwise and twisted wires S are twisted counterclockwise. Twisted wires Z are therefore twisted in the same direction as the gyratory direction of the terrestrial projectiles, which allows the filaments of the wire to advantageously maintain better cohesion during an impact.

According to one embodiment, the polyester threads used have a resistance between 75 N and 110 N and preferably between 101.5 N - 103.9 N.

According to one embodiment, the polyester yarns used have a elongation between 8 and 25%, and preferably between 12-14%.

According to one embodiment, the polyester yarns used have a count between 800 and 4000 den, preferably between 1000 and 3000 den and preferably close to 1000 den or 1100 dtex.

According to one embodiment, the multilayer ballistic protection panel comprises between 5 and 120 layers of fabric woven with twisted polyester threads, preferably twisted Z.

According to an embodiment relating to a splinter guard behind a steel plate, produced with twisted polyester threads Z of title equal to 1000 denier, the multilayer panel comprises between 40 and 50 layers of fabric, and preferably 45 layers of fabric, woven with twisted polyester yarns, preferably twisted Z, of a title equal to 1000 den or 1100 dtex.

According to another variant produced with twisted polyester threads of a title equal to 3000 denier, the multilayer panel comprises between 15 and 22 layers of fabric, and preferably 18 layers of fabric, woven with twisted polyester threads, preferably twisted Z , of a title equal to 3000 den.

According to one embodiment, the fabric of the fabric layers is woven with a density, in number of warp threads by number of weft threads for 0.5 cm ² of fabric, between 5x5 and 8x8 and preferably close to 7x7 for twisted polyester yarns, preferably twisted Z, of a title equal to 1000 den or 1100 dtex.

According to another embodiment, the fabric of the fabric layers is woven, for example in flat braided weaving (Braided plain), with a density, in number of warp threads per number of weft threads for 0.5 cm ² of fabric, between 3.35x3.35- and 5x5, and preferably close to 4.53x4.53 for twisted polyester yarns, preferably twisted Z, of a title equal to 3000 den. Such a wire corresponds for example to three wires of 1000 den each, twisted Z so as to form a single wire.

The invention also teaches the use of such a multilayer ballistic protection panel for the production of an interior or exterior coating for a vehicle, a coating or an accessory for ballistic protection or a door plating, wall or partition.

By way of examples, such a multilayer ballistic protection panel can be used for the production of a passenger compartment wall, hood panel, under the vehicle face, wheel arch, of a protective clothing of the vest type or bulletproof jacket, full suit of demining, a ballistic protection accessory like helmet, shield, or a door, wall plating or partition of the door type or armored partition of building, cabin, shielded enclosure, or of a piece of furniture of the seat or office type.

The invention also teaches an armored composite panel comprising a shielding wall and a ballistic protective coating, and the ballistic protective coating of which is a multilayer ballistic protective panel, as presented above.

According to the embodiments, the shielding wall of this composite panel can be a steel plate, an aluminum plate, an aluminum foam plate, a titanium plate, a fiberglass plate (FPR) , a glass or glass / ceramic plate, a polycarbonate plate, a multilayer plate of aramid fibers, a multilayer plate in UHMWPE, a monolithic ceramic plate or an assembly of ceramic plates or modules or an assembly of perforated metal plates.

According to one embodiment of the composite panel, the multilayer ballistic protection panel is assembled against the shielding wall by gluing or mechanical fixing.

Depending on the applications envisaged, this armored composite panel can be a wall element of a vehicle, a construction panel, a door, a wall or a partition, a part of a piece of furniture, a wall of a seat, or an element of ballistic protection clothing, helmet or shield.

For example, a multi-layer panel can be placed inside any type of door during its manufacture depending on the level of protection required.

It is possible to use an existing door, or even a door made of PVC material, by fixing the multilayer panel to it with a decorative motif encrusted on one side, either by gluing, or by means of another mechanical fixing system. discreet and thus obtain bulletproof protection. There is also a gain in costs and installation time.

Finally, the invention teaches a method of manufacturing such a multilayer ballistic protection panel. This process includes the following steps:

. Make or supply layers of fabric woven with twisted polyester threads and layers of adhesive made of polyethylene-based thermoplastic material,

. Alternate layers of fabric and layers of adhesive,

. Place the overlay or make it directly on a plate of an HPL (High Pressure Laminated) thermo-lamination press, . Close the press and increase the temperature and increase the pressure on the overlay to a pressure value sufficient to allow good diffusion and distribution of heat inside the press so as to melt the thermoplastic material of the layers. the adhesive, and compacting the superposition to cause the molten thermoplastic material to pass through the interstices of the fabric layers until the adjacent adhesive layers come into contact,

. Then initiate the press cooling cycle, without opening the press and maintaining the maximum pressure exerted on the overlay, to cause the solidification of the thermoplastic material, thus ensuring the cohesion of the overlay in the form of a compact multilayer panel,

. Open the press and take out the multilayer panel obtained.

According to one embodiment of this process, during the pressure heating phase, the temperature can be increased, for example on this type of HPL press, to a value between 135 ° C and 165 ° C and preferably between 135 and 154 ° C at the heart of the multilayer panel and increase the pressure to a value between 90 and 200 bars (kg / cm ² ) and preferably up to a value of 110 bars (kg / cm ² ).

According to one embodiment of the method, during the cooling phase, the temperature can be reduced to a value between 50 and 70 ° C and preferably between 60 and 65 ° C, before opening the press to extract the multilayer panels.

Such a temperature makes it possible to consider that the adhesive is solidified and advantageously makes it possible to reduce the time during which the multilayer panels are inside the press.

The multilayer panel according to the invention is produced from readily available high-yield raw materials. With a cost substantially reduced by four compared to those of the prior art made from aramid fibers and UHMWPE. It is therefore much more economical.

In addition, it is much less sensitive to environmental conditions, is not or very little sensitive to UV, humidity or ambient temperature. It thus has a long service life, much longer than that of aramid fiber panels, and for example greater than the service life of a vehicle in which it could be installed. The savings achieved over the lifetime of a vehicle are therefore considerable.

In addition, the adhesive material used being thermoplastic, the multilayer panel according to the invention can easily be recovered to be repaired, modified or improved. Multilayer panels can, if necessary, be repaired by hot repressing after removing projectiles and fragments of any kind, or can be improved by adding additional layers of polyester fabric, or even be joined by pressing one against the other several panels for example of thinner thickness in order to obtain a more resistant panel.

In addition, the fibers are waterproof, but not at all breathable, and the adhesives used to form the panel according to the invention are recyclable and much less toxic in the event of combustion than aramid panels.

On the other hand, the panels according to the invention can be easily implemented industrially for example by forming, thermal or mechanical cutting with conventional mechanical means, which may be more difficult to achieve on materials using aramid fibers.

The multilayer panel according to the invention therefore has many advantages over those of the prior art for comparable or even improved efficiency.

In fact, the very high pressure compacted multilayer panels according to the invention are mechanically very resistant and have particularly advantageous ballistic properties which allow them to advantageously replace panels made of aramid fibers, glass fibers, UHMWPE,

Indeed, and surprisingly, while polyester yarns are much less resistant than aramid fiber yarns, they make it possible to obtain ballistic protection panels that are just as effective because of their much better elongation capacity.

Thus, instead of opposing the penetration of the projectile by the interposition of son of very high tenacity extremely resistant, the panel according to the invention absorbs and dissipates the kinetic energy of the projectiles by a great capacity of elongation of the son as well as by a technical weaving which makes it possible to have more threads per half - cm ² (0.5 cm ² ) which compose it and by the progressive deformation of the successive layers of fabric until the projectile is stopped and / or fragments of any kind. The choice of the density unit per half cm ² is advantageous insofar as an impact of projectiles often takes place on a very small surface.

The multilayer panel according to the invention is thus particularly effective as a splinter guard and as a ballistic coating (ballistic liner) against medium hard projectiles (+/- 30 HRc) with high energy, for example of the FSP (Fragment Simulating Projectiles) type. ) who are hardly stopped by traditional steel shields. In addition, it is not necessary to increase the thickness of the shielding steel, in particular at T ° of -40 ° C when it is combined with a multilayer panel according to the invention.

In a particularly interesting manner, it also makes it possible to effectively retain the fragments of projectile and fragments of wall propelled in other directions by the projectile and likely to cause very significant damage. This splinter-proof function of the panel according to the invention will be described in more detail in the description below.

According to an essential characteristic of the invention, the polyester yarns of the fabric layers are twisted, preferably twisted Z. Unexpectedly, this characteristic makes it possible to obtain an improvement in the efficiency of the multilayer panel according to the invention by improving its resistance. to projectile penetration.

Indeed, with conventional untwisted yarns, the fibers are all oriented in the same direction corresponding to the longitudinal direction of the yarn. When a projectile strikes such a wire, its pointed end spreads its parallel filaments which make up the wire and passes through said filaments. On the contrary, with twisted wires, for example in the same direction as the gyratory direction of the pointed projectile, the filaments have a much greater cohesion. As a result, these filaments are much more difficult to separate when a projectile strikes the twisted wire and more effectively oppose the penetration of the projectile.

This characteristic has yet another particularly advantageous technical effect, because it allows, by giving a twist to the polyester yarns, to obtain yarns of a thinner and more compact diameter. This allows more threads to be inserted while leaving enough free space between the meshes of the woven threads. This improves the penetration of the molten thermoplastic of the adhesive layers between the threads of the fabric layers and thus guarantees better bonding of the multilayer panel with less delamination phenomenon.

Thanks to the use of twisted threads, it is possible to carry out a tighter weaving to increase the density of threads of the fabric and thus improve the overall resistance of the multilayer panel, while leaving between the threads free interstices of sufficient size to guarantee satisfactory bonding.

The multilayer panel according to the invention is advantageously modular and adapted, by the choice of the number of layers of fabric of the panel, to the nature of the threat which it must face and to the intended application. This choice can be done at the initial manufacturing and can also be re-evaluated later by the subsequent addition of additional layers and / or by the addition of several already pressed panels, by performing a pressure assembly of the assembly, in order to obtain the resistance calculated for specific protection.

Another remarkable advantage of the multilayer panel in accordance with the invention resides in the fact that it withstands fire and burns from incendiary projectiles of the API type in particular and that it does not allow BZ gas to pass (API and API BZ), gas BZ or 3-quinuclidinyl benzilate being an incapacitating anticholinergic agent blocking the action of acetylcholine in the nervous system.

Another remarkable advantage of the multilayer panel according to the invention lies in the fact that it retains its properties and mechanical properties at low temperatures ranging at least down to -54 ° C. It thus keeps a relative flexibility by being insensitive to freezing.

In addition, each side of a multilayer panel according to the invention can be used interchangeably as a leading face, unlike a known material based on aramid.

The multilayer panel according to the invention also resists incendiary projectiles because it does not burn.

Another non-negligible advantage lies in the possibility of cutting the multilayer panel according to the invention using a laser beam. The thermal energy provided by the laser beam makes it possible to achieve a very localized fusion along the cutting line of the thermoplastic material constituting said multilayer panel. Such a cutting operation makes it possible to make said multilayer panel waterproof, in particular by cauterization at the cutting edges.

Another remarkable advantage of the multilayer panel according to the invention lies in the fact that it retains all its mechanical properties and its performance and this up to about 1 cm from its edge, while articles based on aramid fibers and UHMWPE usually have a dead zone (low efficiency) of about 5 cm measured from their edge.

The multilayer panel according to the invention also retains all its mechanical properties and its performance during multiple impacts of projectiles which are only 1 cm apart.

Furthermore, the multilayer panel according to the invention has excellent resistance to attack by sharp objects such as daggers, bayonets or the like. Brief description of the figures

Other characteristics and advantages of the invention will appear on reading the detailed description which follows, which is given for information and is in no way limitative, with reference to the appended drawings, in which:

- Figure 1 is a schematic cross-sectional view of an example of a multilayer panel according to the invention;

- Figures 2 and 3 are schematic representations of a weaving respectively flat for Figure 2 and braided for Figure 3, made using conventional straight son (untwisted);

- Figures 4 and 5 are schematic representations of a weaving respectively flat for Figure 4 and braided for Figure 5, this time made using twisted son;

- Figures 6a, 6b and 6c schematically illustrate the successive stages of the penetration of a projectile into a multilayer panel according to the invention shown in section;

- Figure 7a is a front view of the multilayer panel of Figure 6c in which the projectile has been stopped;

- Figure 7b is a side view, in section of a multilayer panel according to the invention, illustrating the progressive penetration and deformation of a projectile;

- Figure 8 is a perspective view of an example of a composite panel according to the invention formed of a steel armor plate and a ballistic protective coating consisting of a multilayer panel according to the invention;

- Figures 9a and 9b are schematic sectional views which compare comparatively the behavior of projectiles passing through a single steel plate for Figure 9a and a steel plate coated with a multilayer panel according to the invention for Figure 9b ;

- Figures lOa and lOb are photographs of the two faces of a composite panel, formed of a steel plate coated with a multilayer panel according to the invention, having undergone firing tests of several projectiles;

- Figure 1a is a front view of another example of a composite panel according to the invention formed from an assembly of hexagonal ceramic plates, attached to a multilayer panel according to the invention;

- Figure 1 lb is a side view, in section, of another embodiment of a composite panel according to the invention;

- Figures l2a, l2b and l2c are schematic sectional views which illustrate comparatively the behavior of a projectile passing through a ceramic plate, only for Figures 12a and 12b, and coated with a multilayer panel according to the invention for Figure 2c;

- Figure 13 is a schematic sectional view which illustrates the method of manufacturing a multilayer panel according to the invention by hot pressing under pressure.

Detailed description of the invention

The multilayer ballistic protection panel according to the present invention will now be described in detail with reference to Figures 1 to 13. The equivalent elements shown in the different figures will bear the same numeric or alphanumeric references.

Several figures have been shown in the various embodiments of a multi-layer ballistic protection panel 1.

The one shown in section in FIG. 1 has four layers of fabric 2 between which three layers of adhesive 3 are inserted.

Of course, this is only an illustrative example, the number of layers being adapted to the protection sought and which can be for example between 5 and 120 layers of fabric, or even more if necessary and depending on the capacity of opening of the press allowing the introduction of large thicknesses according to the protection needs of the applications.

The fabric layers 2 are produced from polyester yarns 4 (polyethylene terephthalate, also known as oxyethylene oxyterephthaloyl PET) which are woven to form the fabric 2.

Depending on the way in which the polyester yarns 4 are interlaced, different weaving patterns are obtained. The multilayer panel of the invention is not limited to a particular weaving pattern for the production of fabric 2, several patterns being perfectly suitable.

One can thus advantageously use a flat weaving as shown in FIG. 2 for which each time a weft thread 5 crosses a warp thread 6, or a braided weaving, also called Panama weaving, as shown in FIG. 3 in which the wires cross each other in pairs, two weft threads 5 crossing two warp threads 6.

But whatever the pattern chosen, there are, due to this weaving, interstices 7 which are free spaces passing through, located between the wires 4 and more precisely between the meshes formed by the interlacing of the wires 4.

The adhesive layers 3 are composed of a thermoplastic material 8, consisting of one or more chemical compounds based on polyethylene LLDPE - LDPE & HDPE (used in this case as a hotmelt).

As can be seen in Figure 1, the thermoplastic material

8 crosses the layers of fabric 2 passing through the gaps 7 existing between the meshes of the fabric and connects the layers of adhesive 3 with each other. Preferably, the thermoplastic material 8 completely fills all the interstices 7 of the fabric layers 2 and completely covers and surrounds the fabric layers 2, even forming a film of thermoplastic material 8 on the surface of the panel 1 on its upper face 9 and its underside 10 in particular. The thermoplastic material 8 thus advantageously ensures the overall cohesion of the multilayer panel 1.

Advantageously, the adhesive layers should preferably be colored and not transparent. This allows the exit of the press after a visual check on the panel, to verify that the bonding is optimal by simply observing the color homogeneity over its entire surface of the panel.

The polyester yarns 4 are conventionally composed of a multitude of rectilinear polyester filaments, oriented substantially in the longitudinal direction of the yarn as shown diagrammatically in FIGS. 2 and 3.

In order to produce the multilayer panel according to the invention, advantageously twisted polyester yarns 4 are used as shown diagrammatically in FIGS. 4 and 5. The polyester yarns are thus twisted on themselves several times according to an oblique torque at the longitudinal direction of the wire.

The polyester yarns 4 used have thus undergone a variable number of twists according to the embodiments, but generally between 40 to 80 twists per meter of yarn and preferably corresponding to about 60 twists per meter of yarn.

It is thus noted, as can be seen in Figures 4 and 5, that in the case of twisted son, the interstices 7 are larger than with the non-twisted son of Figures 2 and 3. A greater amount of thermoplastic material 8 can thus pass through the fabric 2 to join the different layers of adhesive 3 and improve the overall cohesion of the multilayer panel 1.

In order to obtain a multilayer panel 1 of high resistance, it is preferable to choose wires 4 of high tenacity having a resistance between 75 N and 110 N and preferably between 101.5 N - 103.9 N.

These yarns preferably have an elongation of between 8 and 25%, and preferably between 12-14%, giving them a greater range of deformation than aramid and UHMWPE fibers (whose elongation is between 2.4 and 3 , 5%), to absorb energy from projectiles.

The titration of the son 4 chosen is variable and for example between 800 and 4000 denier, preferably between 1000 and 3000 denier, and even more preferably close to 1000 den (1100 dtex).

With such twisted threads, it is possible to make a very tight weave in order to increase the density of threads to half a square centimeter, which is very important for stopping sharp projectiles of small diameters (5-8mm). At the same time, the resistance of the fabric 2 is increased, while ensuring satisfactory bonding due to the presence of gaps 7 of sufficient size.

With twisted polyester threads of a title equal to 1000 deniers, it is thus possible, for example, to obtain a density (in number of warp threads by number of weft threads per 1/2 cm ² of fabric) of between 5 × 5 and 8 × 8, and preferably 7x7.

By way of example, multilayer panels 1 comprising between 40 and 50 layers of fabric 2 have been produced with these fabrics 2. Panel 1 having 45 layers of fabric 2 has been preferred.

With twisted polyester threads of a title equal to 3000 deniers, it is possible, for example, to obtain, for fabric 2, a density of between 3.35 × 3.35 and 5 × 5, preferably 4.53 × 4.53 for twisted polyester threads of titer equal to 3000 den.

By way of example, multilayer panels 1 comprising between 15 and 22 layers of fabric 2 have been produced with these fabrics 2. Panel 1 comprising 18 layers of fabric 2 has been preferred.

In order to illustrate the principle of the ballistic protection function of the multilayer panel 1 according to the invention, the stroke of a projectile striking the multilayer panel 1 at its upper face 9 has been shown chronologically in FIGS. 6 to 7a and 7b.

As can be seen in the chronological succession of FIGS. 6a to 6c, when a projectile 12 reaches the upper face 9 of the multilayer panel 1, it begins by sinking into the thickness of the panel by digging a bowl 13 therein. at its high kinetic energy allowing it to break the wires 4, it crosses the first layers of fabric 2. It is however braked and deformed gradually by the layers of fabric 2 which, before breaking, are deformed due to the significant elongation capacity of the polyester yarns 4 and which in this way absorbs a large part of the energy of the projectile 12.

Thus, FIG. 7b illustrates the penetration of the projectile 12, which deforms the successive layers of tissue 2 and deforms progressively to present a shape of a mushroom which is increasingly marked as a function of the degree of penetration into the multilayer panel 1. The resistance of the layers of fabric 2 not perforated by the projectile 12 causes the deformation of said projectile 12. The contact surface of the projectile 12 thus increases and therefore its braking also increases.

If the number of layers of fabric 2 of the multilayer panel 1 is sufficient, the projectile 12 ends up immobilizing without passing through the underside 10 of the multilayer panel 1, as shown in section in FIG. 6c or seen from above in FIG. 7a .

The multilayer panel 1 according to the invention, used alone, thus makes it possible to effectively stop pistol bullets, revolvers and submachine guns and moderate kinetic energy projectiles such as buckshot and bullets. It is therefore perfectly suited for the production of inserts (Vests) for vests, jackets or other bulletproof clothing or very thin and flexible inserts to be inserted on the rear part, to reduce trauma and increase the level resistance relating to existing bulletproof vests made of aramid fibers or UHMWPE.

In addition, as visible in FIG. 6c, the panel 1 has, after impact of the projectile 12, a limited deformation on its underside 10 preventing the occurrence of serious internal trauma when it is used as a trauma reducer in bullet-proof vests.

Depending on the type of projectiles which one wishes to resist, it is possible to combine the multilayer panel 1 with very high hardness steel or ceramic to retain the projectiles 12 with cores of hardened steel and Tungsten, which are much harder materials.

To deal with perforating and incendiary projectiles, a composite panel 14 can be produced comprising at least one shielding wall 15 and a multilayer panel 1 serving as a ballistic protective coating 16 (also called a "ballistic liner") as shown in the figure. 8.

The multilayer panel 1 serving as a ballistic protective coating 16 is preferably assembled against the shielding wall 15 by gluing or by mechanical fixing. It can also be fixed at a certain distance from the shielding wall 15.

Advantageously, the shielding wall can be a steel plate 17 and preferably a steel plate having a hardness of 600HB according to standard EN ISO 6506-1.

The composite panel 14 is then capable of effectively retaining projectiles coming from portable weapons of the infantry in general as well as the fragments of metal coming from hand grenades and land mines.

In this configuration (when the multilayer panel 1 is used as a ballistic liner), it also performs an interesting function of splinter guard shown in FIGS. 9a and 9b.

Indeed, even if they are retained by the shielding wall 15, for example made of steel, the projectiles 12 can rupture and project projectile fragments 18 or else tear off fragments of wall 19 which are projected in directions different from the initial trajectory of the projectile 12 and can prove to be extremely lethal. The occupants of an armored vehicle whose steel wall has retained a penetrating projectile 12 can thus be very seriously injured by fragments of this wall when they were not even in the trajectory of the projectile.

As can be seen in FIG. 9b, when the wall 15 is coated with a multilayer panel 1, the projectile fragments 18 and the wall fragments 19 are retained by the multilayer panel 1 which deforms to contain them in a bowl. 13, regardless of the direction in which they are propelled.

In order to demonstrate the effectiveness of the invention, ballistic tests were carried out on several examples of the implementation of the invention consisting of a multilayer panel 1 comprising 45 layers of fabric 2, glued in contact with a plate 7.5 mm thick ballistic protection steel 17 with a nominal hardness of 600 HB, on which armor-piercing projectiles and 20 mm FSP projectiles were fired in accordance with STANAG 4569 level 2 at -40 ° C .

The post-impact photographs of the two faces of the composite panel 14 tested are presented in FIGS. 10a and 10b.

As can be seen in FIG. 10a, three piercing projectiles (2-1, 2-2 and 2-3) and three FSP projectiles (1, 2 and 3) reached the composite panel 14 and impacted its plate. steel 17.

As can be seen in FIG. 10b, none of these projectiles has passed through the composite panel 14 and has not torn the outer face of the multilayer panel 1, thus demonstrating the effectiveness of the composite panel 14 in terms of material. ballistic protection.

Such composite steel / multilayer panels can be used, for example, to make shielding walls for civil vehicles, police forces, cash and military transport.

Depending on the applications, the shielding wall 15 can also be formed from a plate of ceramic material or, as shown in FIG. 1 a, from a set of ceramic plates 22, for example hexagonal, retained by a binder 23.

FIG. 11b illustrates, by way of example, another example of application of the multilayer panel 1. The latter is for example sandwiched between a ceramic shielding plate 15 and a steel or aluminum plate 30 using layers adhesives 31. Such a shielding sub-assembly can then be glued by means of an additional adhesive layer 32 and / or mechanically fixed by bolting with a bolt-nut assembly 32a on an external wall 33 of steel, aluminum or other material. .

The splinter protection function of the multilayer panel 1 in association with a shielding wall 15 of ceramic plates has also been shown in FIGS. 12a to 12c.

In FIGS. 12a and 12b, it can be seen that when the ceramic shielding wall 15 is alone, the projectile 12 crosses it by fracturing and disintegrating the ceramic plate 22 and the binder 23. The projectile 12 can come out continuing its travel, while projecting wall fragments 19 in other directions.

When the ceramic shielding wall 15 is combined with a multilayer panel 1, as shown in FIG. 12c, the projectile 12 like the wall fragments 19 are retained by the multilayer panel 1 serving as a ballistic liner.

With a ceramic armor plate 15, the composite panel 14 is capable of effectively resisting projectiles from large caliber military weapons or against multiple projectiles.

Such ceramic / multilayer composite panels can be used, for example, to make shields.

The multilayer panel 1 according to the invention is preferably a compact laminated panel, also called compact laminate, produced by hot pressing under high pressure. To achieve this, we use a thermo-lamination press of the HPL (High Pressure Laminate) type capable of producing heating and cooling cycles (Hot / Cooled) under high pressure.

An example of a method for manufacturing a multilayer panel 1 according to the invention has been illustrated diagrammatically in FIG. 13.

After having made or purchased the necessary layers of fabric 2 and the layers of adhesive 3, a superposition 24 is produced by alternately stacking the layers of fabric 2 and the layers of adhesive 3.

This superposition 24 is then placed between the two plates 25 of an HPL type thermo-lamination press 26. Alternatively, the superposition 24 can be carried out directly inside the press 26.

The press is closed and a heating cycle is initiated in order to obtain the melting of the thermoplastic material 8 of the adhesive layers 3. Inside the press, the temperature is thus gradually increased to a value between 135 ° C and 165 ° C.

Once the thermoplastic material 8 has reached its melting point, the pressure inside the press is increased, to a value preferably between 90 and 200 bars, for example equal to 110 bars, of so as to compact the superposition 24 by bringing the two plates 25 of the press 26 towards each other as symbolized by the arrows 27 in FIG. 13. The choice of the temperature and pressure values in the ranges mentioned above depends on the thickness of the multilayer panel 1 to be produced.

This causes the passage of the molten thermoplastic material 8 through the interstices 7 of the fabric layers 2. The gradual increase in pressure causes the thermoplastic material to completely fill the interstices 7 and connect the various layers of adhesive 3. It even covers the upper and outer fabric layers 2, thus constituting a film of thermoplastic material on the upper 9 and lower 10 sides of the panel 1.

This superimposition of the superposition 24 under very high pressure also makes it possible to obtain compression of its different layers of fabric 2 and of adhesive 3, thus leading to the production of a compact multilayer panel 1 (that is to say say whose final height is less than the sum of the initial height of the layers making it up).

A cooling cycle is then carried out inside the press 26 while maintaining the maximum pressure on the panel. The temperature is thus reduced to a value preferably between 50 and 70 ° C and for example of the order of 60 to 65 ° C. On cooling, the thermoplastic material 8 solidifies and then ensures the cohesion of the superposition 24 in the form of a compact multilayer panel 1, The press 26 can then be opened and the multilayer panel 1 obtained therefrom.

In this way and depending on the shape of the plates 25 of the press 26, it is possible to obtain flat panels or formed parts.

Other variants of the multilayer panel 1 according to the invention can obviously be imagined without departing from the scope of the claims below.

The multilayer panel 1 can for example further comprise at least one decorative outer layer, on one or both of its outer faces. This decorative layer can advantageously be added directly during the pressing of the multilayer panel. This can include a plastic or paper decor glued with a melanin film called "overlay".

According to another exemplary embodiment, the fabric layers 2 of the multilayer ballistic protection panel 1 may comprise, in addition to the fabric layers of 1000 den polyester yarn, at least one layer woven with aramid or polyethylene yarns of very molecular weight. high (UHMWPE) or preferably, for reasons of economy, with a layer woven with polyester threads of 3000 den on the outer face (s).

Claims

1. Multilayer ballistic protection panel (1) comprising a superposition of layers of fabric (2) into woven threads (4), the weaving leaving free interstices (7) passing through between the threads (4) in each layer of fabric (2 ), and layers of adhesive (3) which are alternately interposed between the layers of fabric (2) and which ensure the overall cohesion of the multilayer panel (1), multilayer panel (1) characterized:

in that the layers of fabric (2) in woven yarns (4) comprise layers of fabric (2) woven with twisted polyester yarns (4),

in that the adhesive layers (3) are layers of a polyethylene-based thermoplastic material (8).

and in that the thermoplastic material (8) passes through the interstices (7) of the fabric layers (2) and connects the adhesive layers (3) with each other, thus ensuring the overall cohesion of the multilayer panel ( 1).

2. Multilayer panel (1) ballistic protection according to claim 1 characterized in that it is a compact laminated panel produced by hot pressing under high pressure.

3. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that the fabric of the fabric layers (2) woven with twisted polyester yarns (4) is woven in a flat weaving pattern or mat.

4. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that the polyester yarns (2) are twisted Z or S, preferably twisted Z, with 40 to 80 twists per meter of yarn and preferably about 60 twists per meter of wire.

5. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that the polyester yarns (2) have a resistance between 75 N and 110 N and preferably between 101.5 N - 103 , 9 N.

6. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that the polyester yarns (2) have an elongation of between 8 and 25%, and preferably between 12-14%.

7. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that the polyester yarns (2) have a count between 800 and 4000 den, preferably between 1000 and 3000 den and preferably close to 1000 den.

8. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that it comprises between 5 and 120 layers of fabric (2) woven with twisted polyester yarns (4).

9. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that it comprises between 40 and 50 layers of fabric (2), and preferably 45 layers of fabric (2), woven with polyester yarns (4) twisted with a title equal to 1000 den.

10. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that it comprises between 15 and 22 layers of fabric (2), and preferably 18 layers of fabric (2), woven with twisted polyester yarns (2), preferably twisted Z, of a weight equal to 3000 den.

11. Multilayer panel (1) for ballistic protection according to any one of the preceding claims, characterized in that the fabric of the fabric layers (2) is woven with a density, in number of warp threads per number of weft threads 0.5 cm ² of fabric, between 5x5 and 8x8 and preferably close to 7x7 for twisted polyester yarns, preferably twisted Z, of a title equal to 1000 den.

12. Multilayer panel (1) for ballistic protection according to any one of claims 1 to 10 characterized in that the fabric of the fabric layers (2) is woven with a density, in number of warp threads by number of weft for 0.5 cm ² of fabric, between 3.35x3.35 and 5x5, and preferably close to 4.53x4.53 for twisted polyester yarns (2), preferably twisted Z, of a title equal to 3000 den .

13. Use of a multilayer ballistic protection panel (1) according to any one of claims 1 to 12 for the production of an interior or exterior coating of a vehicle, of a ballistic protection garment or accessory, or a door, wall, or partition wall plating.

14. Armored composite panel (14) comprising a shielding wall (15) and a ballistic protective coating (16) characterized in that the ballistic protective coating (16) is a multilayer panel (1) of ballistic protection according to any one of claims 1 to 12.

15. armored composite panel (14) according to claim 14 characterized in that the shielding wall (15) is a steel plate (17), aluminum plate, aluminum foam, titanium plate, fiber plate glass, aramid fiber multilayer plate, UHMWPE multilayer plate, polycarbonate plate, an assembly of perforated metal plates or a plate monolithic ceramic, or an assembly of ceramic plates (22).

16. armored composite panel (14) according to claim 14 or 15 characterized in that the multilayer panel (1) for ballistic protection is assembled against the armor wall (15) by gluing or mechanical fixing.

17. armored composite panel (14) according to any one of claims 14 to 16 characterized in that it is a wall element of a vehicle, a construction panel, a door, a wall or a partition, a part of a piece of furniture, a wall of a seat, or a piece of clothing, helmet or ballistic protection butcher.

18. A method of manufacturing a multilayer ballistic protection panel (1) according to any one of claims 1 to 14 characterized in that it comprises the following steps:

- Make or supply layers of fabric (2) woven with twisted polyester yarns (4) and layers of adhesive (3) made of thermoplastic material (8) based on polyethylene,

- Alternate layers of fabric (2) and layers of adhesive (3),

- Place the superposition (24) or make it directly on a plate (25) of a press (26) of thermo-lamination of HPL type (High Pressure Laminated),

- Close the press and increase the temperature and pressure on the overlay to a pressure value sufficient to allow good diffusion and distribution of heat inside the press so as to melt the thermoplastic material of the layers of adhesive and to compact the superposition to cause the passage of the molten thermoplastic material through the interstices of the fabric layers until contacting the adjacent adhesive layers,

- Then initiate the press cooling cycle, without opening the press and maintaining the maximum pressure exerted on the overlay, to cause the solidification of the thermoplastic material, thus ensuring the cohesion of the overlay in the form of a compact multilayer panel ,

- Open the press (26) and take out the multilayer panel (1).

19. The manufacturing method according to the preceding claim characterized in that the temperature is increased to a value between 135 ° C and 165 ° C at the heart of the multilayer panel (1), depending on the thickness of the multilayer panel ( 1) and increase the pressure to a value between 90 and 200 bars (kg / cm ² ) and preferably up to a value of 110 bars (kg / cm2).

20. The manufacturing method according to claim 18 or 19 characterized in that the temperature is reduced to a value between 50 and 70 ° C and preferably between 60 and 65 ° C, before opening the press (26) to extract the multilayer panels (1) .