FR2459956A1 - Ballistic screens partic. for bulletproof sheeting for car body mfr. - incorporates laminate of fibrous materials combined with metal sheet, light in wt. and thin - Google Patents

Abstract

Ballistic screen partic. for the realisation of bullet proof sheeting used e.g. for the making of car bodies of the kind formed from a lamination, comprises at least two layers of fibrous material placed on either side of a core and joined to it by a polyester resin. Core is made of material of low density and high plasticity. These layers form structures for one side of the core which are plastically deformable under the impact of a bullet because of the plasticity characteristics of the core. They also form a cushion for the other side of the core, these plastically absorbent strata being combined with screens of high density and resilience. They are pref. coated on the impact side with a gel coat which is in contact with the wall of the protective material, e.g. a metal sheet. Material weighs less per square m than existing materials, and it is thinner, this fact facilitating its putting into place and its presentation in the form of sheets which can be cut up or preformed. It is suitable for forming in contact with a thin metal sheet a safety complex partic. well adapted to the motor car industry, but also car screens for all uses.

Description

 The invention relates, in general, to improvements: made to ballistic screens.

 The invention relates more particularly to the shielding of bodies, envelopes, protective screens and in particular the shielding of so-called thin sheets, such as those used in the civil industry for lining doors or making automobile bodies.

 We have proposed a whole range of solutions to the problem posed by the shielding of screens or bodywork, but they all simultaneously present a major drawback: they use heavy, thick materials, most often metallic, which makes this type often impossible operation, for example on civilian vehicles whose structures and also the power are insufficient to support the weight of such armor.

 Furthermore, whatever the nature of the materials used, the excessive thickness constitutes a serious handicap to the adaptability to vehicles not initially designed to receive such armor thicknesses.

 There is therefore a strong need for a material capable of constituting shielding panels, which would be free from the aforementioned drawbacks, such as to be fully approved by the manufacturers and the users, and to provide a strong guarantee of protection, in particular against civil weapons fire or those belonging to the range known as of free sale.

 An object of the invention is therefore to provide a shielding material which is proof against shooting projectiles, of low weight per square meter, of small thickness to facilitate its installation and which can be in the form of cutable or preformed plates. .

 Another object of the invention is to provide a shielding material capable of forming, in contact with a thin sheet, a security complex particularly well suited to the automotive industry, but also to the constitution of screens for all purposes.

 Another object of the invention is to provide a shielding material of which some of its constituents have a high cohesive power without risk of delamination under the impacts of projectiles.

 The invention is based, to achieve these goals, on the unexpected properties of certain types of laminated materials whose components, in a particular distribution of the layers, allow the realization of combined energy absorption zones, capable of stopping the race of a shooting projectile.

 To this end, the invention relates to improvements made to ballistic screens, in particular for the production of armor proof against firing projectiles, of the kind formed from a laminate, characterized in that it comprises on both sides of a gme of material with low density and high plasticity, at least two layers of woven or non-woven fibrous materials, linked in whole or in part by a polyester resin, these strata forming for one side of this core plastically deformable networks under the impact of a projectile, thanks to the plastic characteristics of this core, these strata also forming, for the other side of this core, a compression mattress for the thus coated double-sided core, these plastically absorbent strata being combined with high density and high resilience screens.

 Thanks to this basic structure, thin, light screens are formed, formed from several energy absorption zones of different characteristics, the outermost being preferably hard, and slightly deformable, the innermost preferably less hard, but having plastic deformation properties, which makes it possible to stop without crossing most of the firing projectiles, known as "over-the-counter '.' but also war projectiles.

 According to a provision of the invention, in its application to shielding, the strata on the firing impact side are coated with a gel-coat, which is in contact with the wall of the material to be shielded, for example a sheet.

 According to another arrangement of the invention, at least one of the strata, on the firing impact side, is made of woven material based on organic fibers of the aromatic polyamide type, called aramid with high tensile strength.

Other characteristics of the invention will emerge from the detailed description which follows, of various embodiments of a ballistic screen given here by way of example, and represented in the accompanying drawings in which
Figure 1 is a schematic view exploded showing the components of a screen according to a first embodiment.

 Figures 2 to 10 are schematic views showing an exploded view of various arrangements of the components of a screen, according to another embodiment.

 Figure 11 is a schematic view showing an exploded view of the components of a preformed screen.

 According to the invention, FIGS. 1 to 11 show different examples of the execution of ballistic screens, each designated by the general reference 10.

 In the various examples, the same reference numbers indicate materials of identical structure.

Example> t
The screen is made of a laminate which, associated with a thin sheet 12, constitutes a shielding having a significant safety factor, as will be explained below, during a resistance test.

 This screen is first of all made up of a core made of a material with low density and high plasticity, designated by the reference 16. Advantageously, this gme is made of balsa wood, standing, that is to say whose fibers are substantially parallel to the direction of the firing impact designated by the reference 11.

 The balsa string 16 is coated on the firing impact side, with a first layer 15 based on long woven fibers, in particular a roving of glass fibers of 270 g / m2. A second layer 14, in nonwoven, is superimposed on the roving 15 and is made up in particular of a glass mat, advantageously 300 g / m2. The mat 14 is bonded to a surface coating 13, such as a gel-coat.

 On the face opposite to the firing impact, the balsa oar 16 receives a roving layer 15, in turn coated with a nonwoven layer 14, such as glass mat. The different layers are linked by a polyester resin R. The total thickness of the laminate thus produced does not exceed 7.5 mm. We tested a laminated sandwich panel, conforming to the previous one, placed as a door lining, behind a sheet of 12 / 10ths of a millimeter.

- weapon used: rifle 22 LR with 580 mm barrel - medium V 3: 291 m / second - ammunition: 22 LR subsonic hollow point - shooting distance: 15 meters - number of impacts: 3, grouped in a triangle of 35 mm side
Observations The sheet metal t12 / 10e) has three perforations with a diameter of 6 mm - The laminate panel is not crossed by the projectiles - There are fingerprints in the laminate panel with a depth of the order of
5 / 10th of a millimeter.

A sandwich panel of the same composition was then subjected to a second test, as follows - weapon used: hunting rifle caliber 12 with 580 mm "RIOT GUN" barrel - ammunition: buckshot cartridge (12 grains) - shooting distance: 15 meters - number of shots: 1
Observations: We note on a door tate of 12 / 10th of a millimeter, 8 impacts - The laminated panel does not present any perforation - We note 4 very light imprints on the laminate.

Example 2
In the embodiment of Figure 2, the laminate is formed as follows
The balsa core 16 is coated on the firing impact side with a woven material 17, based on organic fibers, of the aromatic polyamic type known as "aramid" with high tensile strength. Such a material is sold commercially under the name ">Kevlar" from the firm Du Pont de Nemours International.

In this example, the grammage of this material is 200 g / m2. This "aramid" is coated with a glass mat 300hi2, a roving270g / m2, then another mat 300gAn2, followed by a gel-coat. Contrary to the impact of shooting, the balsa core 16 is coated with a glass mat 14, followed by a roving 15.

 In the first example of execution, the weight per square meter of the laminate is approximately 4.6 kg whereas in the second example, we obtain a weight of 5.3 kg.

In the second embodiment, the strength performance of the laminate is very significantly improved. We subjected such a laminate to a test in which the sheet is only 10/10 - weapon used: shotgun caliber 12 "RIOT GUN" - ammunition: a cartridge with buckshot (12 grains)
a buckshot cartridge (9 grains) - shooting distance: 15 meters
Observations: The laminate is placed behind a 10 / 10th-millimeter door panel. There is a perforation of the tale.

- The laminate panel is not crossed - There are no fingerprints on the rear side of the laminate
For this same stratification, we carried out a second test, using a 12 gauge shotgun with 580 mm cannon, "RIOT GUN" - ammunition: Blondeau bullet cartridges - shooting distance: 15 meters
- number of shots s 1
Observations: Perforation of the sheet. Dia of impact 23 mm.

- Perforation of a metal reinforcement (thickness 4.5 mm) - Laminated panel, not crossed, presenting on its inner face a deformation
14 cm in diameter and 7 mm high
Example 3
In the embodiment of FIG. 3, the laminate consists of the following layers, from the impact face, to the opposite face - a layer of gel coat 13, a glass mat 14 a layer of aramid woven material, a layer of roving 15, a layer of glass mat 14, the balsa core 16, a glass mat 14, a roving 15.

Example 4
In the embodiment of Figure 4, the laminate consists of a gel coat 13, a roving 15, a mat 14, an aramid woven 17, a roving 15, a balsa core 16, mat 14 and roving 15.

Example 5
In the embodiment of Figure 5, the laminate consists of a gel coat 13, a roving 15, an aramid woven 17, a roving 15, a balsa core 16, d 'a mast 14 followed by a roving 15.

EXAMPLE 6
In the embodiment of Figure 6, the laminate consists of a gel coat 13, a glass mat 14, a first aramid 17a followed by a second aramid 17b, a balsa core 16, a mast 14, followed by a roving 15.

Example 7
In the embodiment of Figure 7, the laminate consists of a gel coat 13, a roving 15, a first aramid 17a, a second aramid 17b, a roving 15, a balsa core 16, a glass mat 14, followed by a roving 15.

Example 8
In the embodiment of Figure 8, the laminate consists of a gel coat 13, a roving 15, a first aramid 17a, followed by a second aramid 17b, a balsa core 16 , a glass mat 14, followed by a roving 15.

Example 9
In the embodiment of Figure 9; the laminate consists of a gel coat 13, a first aramid 17a, a second aramid 17b, a third aramid 17c, a balsa core 16, a glass mat 14, followed by 'a roving 15.

Example 10
In this embodiment, the laminate consists of a gel coat 13, a first aramid 17a, a second aramid 17b, a third aramid 17c, a fourth aramid 17d, a core in balsa 16, with a glass mat 14, followed by a roving 15.

 All the examples of laminates which have just been described lend themselves particularly well to the production of sandwich panels, monolytic, of large dimensions, presently present in the form of flat plates; 7 x 1.50 m; these dimensions are not limiting.

 According to the embodiment described in Example 11, the constitution of the laminate allows the production of preformed panels or plates in which one can combine a flat surface with one or more curves, of the same or different directions, or also a series of curves, these panels finding an application to the lining of sheets, themselves bent or profiled in any way.

 In the example of Figure 11, the laminate consists of a gel coat 13, a glass mat 14 or a roving, and an aramid complex consisting of several woven layers of this material, the fibers being only bonded together by a bead of resin 18, so as to remain free from layer to layer, over the largest surface of the laminate thus produced. The aramid 17th complex is followed by the balsa core 16, then by a roving or mat 14, followed by a roving 15.

 It will be noted that generally speaking, except for example 1, the face opposite to the firing impact always ends in a roving 15. It goes without saying that the grammage indications are given here by way of example for the different strata and that likewise, the thickness of 7.5 mm, although of major interest in the lining, in particular of body sheets, is given here only as an indication.

Note that the constituent materials of the strata are
noncombustible, i.e. classified MO while the bonding resin and
gel-coat are classified M2 according to the CSTB standard

It also goes without saying that the laminate according to the invention,
can itself constitute a ballistic screen without the need to
associate it with a sheet or other complementary screen.

 Of course, the invention is not limited to the embodiments described above and shown for which other variants can be provided, without thereby departing from the scope of the appended claims.

Claims (10)

 1) Improvements made to ballistic screens, in particular for the production of armor proof against projectiles, of the kind formed from a laminate, characterized in that it comprises on either side of a core of material at low density and at high plasticity at least two strata of woven or non-woven fibrous materials, linked in whole or in part to the core by a polyester resin, these strata forming for one side of this core plastically deformable networks under the impact of '' a projectile, thanks to the plastic characteristics of this soul, these stratoeforming also, for the other side of this friend, a compression mattress for the soul thus coated double-sided, these plastically absorbing strata being combined with screens with high high density and resilience.  2) Ballistic screen according to claim 1, characterized in that, in its application to armor, the strata on the firing impact side are coated with a gel coat which is in contact with the wall of the material to be shielded, for example a sheet .  3) Ballistic screen according to claims 1 and 2, characterized in that the strata on the firing impact side comprise in combination at least one layer of non-woven material, such as a glass mat and at least one layer of material based on long non-woven fibers.  4) Ballistic screen according to claims 1 and 2, characterized in that the strata, firing impact side, consist of several layers of material based on long fibers woven but of different nature.  5) Ballistic screen according to claims 1 and 2, characterized in that the strata, firing impact side, consist of several layers based on long woven fibers of identical nature.  6) Ballistic screen according to any one of claims 1 to 5, characterized in that at least one of the strata, impact side of. shot, is made of woven material based on glass fibers.  7) Ballistic screen according to any one of claims 1 and 2, characterized in that at least one of the strata, firing impact side is made of woven material based on organic fibers of the aromatic polyamide genus, called aramid, with high tensile strength.  8) Ballistic screen according to any one of claims 1 to 7, characterized in that the material constituting the core of the complex is wood, preferably balsa, upright or straight.  9) Ballistic screen according to any one of claims 1 to 8, characterized in that, for the production of preformed screens, the layers of strata, caté firing impact, are linked together only by a bead of resin, so as to remain free over most of the surface of a screen,  10) Ballistic screen according to any one of claims 1 to 9, characterized in that, on the side opposite to the firing impact, the last layer is preferably a layer of woven material, of glass fibers of the roving type.