GB2149482A

GB2149482A - Projectile-proof material

Info

Publication number: GB2149482A
Application number: GB08220469A
Authority: GB
Inventors: Harry Apprich
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-08-13
Filing date: 1982-07-21
Publication date: 1985-06-12
Also published as: FR2573193A1; IT1148403B; FR2573193B3; GB2149482B; IT8248982A0

Abstract

A projectile-proof multi-layer material of low weight and high resistance to projectiles comprises a backing layer, of a material having a substantially lower specific weight than iron, covered by individual adjacently and possibly superposedly disposed bodies of a material the hardness of which is greater than that of the backing layer, the bodies being embedded in a synthetic resin layer which at the same time adheres rigidly to the backing layer. The bodies may be granules and/or plates, which may be in adjacent layers. The construction may include a plastics sheet which facilitates the absorption of pressure waves.

Description

SPECIFICATION Prolectile-proof Multi-layer Material The invention relates to a projectile-proof multilayer material.

Known materials of this type, in particular metallic armoured plates, have the disadvantage of being too heavy at a given resistance to projectiles.

The object of the invention is to provide a material which is characterised by a high resistance to projectiles while being of relatively low weight.

According to the invention, such a material has the following layered structure: a) a backing layer consisting of a material having a specific weight which is sustantially less than that of iron; b) the backing layer is covered by individual adjacently and possible superimposedly disposed bodies of a material the hardness of which is greater than that of the backing layer; c) the bodies covering the backing layer are substantially embedded on all sides in a layer of synthetic resin which at the same time adheres rigidly to the backing layer.

The following description of preferred embodiments of the invention will, in conjunction with the appended drawings, serve to provide further explanation. In the drawings: Fig. lisa diagrammatically shows a first embodiment of a projectile-proof multi-layer material; Fig. 2 shows a different embodiment of projectileproof multi-layer material; Fig. 3 is a partial sectional view of the area A of Fig. 1; Fig. 4 is a partial sectional view of the area B in Fig. 2; Figs. 5 to 10 are partial sectional views of further embodiments of projectile-proof multi-layer materials according to the invention; Fig. 11 diagrammatically shows a further embodiment of the multi-layer material; Fig. 12 is a partial sectional view of the area A in Fig. 11;; Fig. 13 is a partial sectional view of a modified embodiment and Fig. 14 is a partial sectional view of two joinedtogether armoured plates made from multi-layer material according to the invention.

In the case of the embodiment of the projectile proof multi-layer material shown in Fig. la a backing layer 1 consists of a material having a specific weight which is substantially less than that of iron.

Such a material may, for example, be aluminium, titanium or even synthetic plastics material. The backing layer is covered with individual adjacently and superimposedly disposed bodies 2 consisting of a material the hardness of which is greater than that of the backing layer 1. In the case of the embodiment illustrated, the bodies 2 consist of particles of hard material in the form of angular silicon and/or boron carbide granulate 3 (see Fig. 3).

The individual particles of granulate 3 are, as Fig. 3 also shows, embedded substantially on all sides in a synthetic resin layer 4 which is at the same time rigidly secured by adhesion to the backing layer 1 so connecting the granulate 3 rigidly to that layer 1.

It has been found that the particles of granulate 3 which consist of hard material will, by reason of their considerable hardness, so deform or even decompose a projectile striking them, particularly the point thereof, that the projectile is no longer capable of penetrating the illustrated multi-layer material, particularly the backing layer 1 thereof. As a rule, the end of the projectile striking the bodies 2 will be forcibly compressed so that it will widen out considerably in comparison with the diameter of the projectile. This widening-out prevents deep penetration into or piercing of the backing layer 1, in particular. It is especially advantageous for the bodies 2 to consist not only of a hard material but to be of angular or edge shape, like grinding particles.

Such an angular construction further favours the above-described process of deformation of the projectile, which in the final analysis prevents penetration of the projectile-proof material. The degree of hardness of the bodies 2 lies between 8 and 10 on the Mohs Hardness Scale, and is preferably between 9 and 10. In addition to the aforementioned carbide materials, for example hard aluminium oxides in the form of corundum or carborundum, and possiblly also hard metals, particularly sintered hard metals, where they fall within the indicated degree of hardness and take the form of an angular granulate, are also suitable. It is well-known that such hard metals are produced (sintered) on the basis of tungsten, titanium or tantalum carbide.

In addition to the metals mentioned at the outset, the backing layer 1 can for its part consist generally of light metal alloy, in particular aluminium alloy. A suitable synthetic material for the production of the backing layer 1 is a polycarbonate or polyvinyl chloride.

The granulation of the bodies 2 which are constructed as particles of hard material is between 1 and 5 and preferably between 2 and 4 mm.

According to the desired resistance to projectiles, so one or more layers of hard granulate 3 or the like may be applied to the backing layer 1 and embedded in synthetic plastics layer 4. Synthetic resins which adhere rigidly to the backing layer 1, for example polyurethane or polyvinyl chloride resins, are suitable materials into which the granulate may be embedded.

In the case of the embodiment of the invention shown in Fig. 2 and 4, the bodies disposed on the backing layer 1 consist of fireproof oxide ceramic plates 5, in particular aluminium oxide plates. The plates 5 are in turn embedded on all sides in a synthetic resin layer 4, consisting for example of polyurethane or polyvinyl chloride resin, which at the same time provides a rigid connection of the plate 5 to the backing layer 1.

While the embodiment of the invention as shown in Fig. 1 offers in the main safety against hand-held firearms, the embodiment according to Fig. 2 also affords protection against long firearms, in particular also against powder train projectiles which, upon impact, generate a considerable amount of heat and to a certain extent "weld their way through" the material. The fire proof plates 5 prevent this.

The plates 5 may be rectangular, square or hexagonal in shape. In the case of square plates 5, the edge length is 18 to 35 and preferably 25 to 30 mm. The use of relatively small plates 5 has the advantage that the cracks occurring due to impact of a projectile can spread only as far as the edge of the plate 5 affected.

The thickness of the plates 5 is advantageously greater than 6 mm and is preferably between 8 and 14 mm.

Since the fireproof plates 5 which may consist, for example, of aluminium oxide, boron carbide or the like, are a hard material, they act on a projectile striking them in the same way as described above in connection with the embodiment shown in Fig. 1.

It has been found that a material according to Figs. 2 and 4, when using oxide ceramic plates 5 having a thickness of up to 10 mm, is capable of absorbing energy up to 4,500 Jouies. For corresponding thickness of the layer formed by the bodies 2, the material according to Figs. 1 and 3 can absorb up to 2,500 Joules.

The multi-layer materials according to the invention are produced in the following way. The surface of the plate forming the backing layer 1, for example a light metal plate of about 6 mm thickness, is mechanically or chemically roughened.

Then, a synthetic resin or an adhesive (for example polyurethane or PVC) is applied. Before the resin or the adhesive is applied, the surface of the backing layer 1 can also be covered with a primer, particularly if it is intended to apply plates 5 to the backing layer. The primer serves to promote adhesion of the backing layer to the synthetic resin or adhesive. In the case of the embodiment according to Fig. 1, granulate 3 or the like is sprinkled onto the layer of synthetic resin or adhesive. Then another coating of resin or adhesive is applied to guarantee complete embedding of the granulate and a rigid connection to the backing layer. With a multi-layer application of granulate 3, it is recommended to apply a layer of synthetic resin between successive layers of granulate.In the case of the embodiment according to Fig. 2, the plates 5 are placed individually onto and impressed into the layer of synthetic resin, it being important for the synthetic resin (or the adhesive) also to penetrate the joints between the plates 5. Then, a further layer of synthetic resin is poured on to coverthe entire surface of the pirates 5 and penetrate the joints between them. Once the synthetic resin has hardened out, the multi-layer material is ready for use.

The embodiment of the invention shown in Fig. 5 differs from that according to Fig. 4 in that an additional synthetic plastics layer 5 is provided between the backing layer 1 and the plate 5 embedded in the synthetic resin 4, the additional layer 6 taking the form of a film or plate. Suitable synthetic plastics materials are in particular polycarbonate or polyvinyl chloride. In the manufacture of the embodiment according to Fig. 5, again the premise is a backing layer 1 of light metal alloy, the thickness of which in this case, as with all other embodiments of the invention, is preferably at least 6 mm. The surface of the layer 1 is roughened, after which a primer is applied, whereupon the glue or resin is applied. Then, a film or plate of synthetic plastics material 6 is pressed on, preferably under high pressure.A further layer of primer is applied to the synthetic plastics material 6. In the manner previously described, the plates 5 embedded in the synthetic resin 4 are dispoed on this layer.

It has been found that the plate or film of synthetic plastics material 6 better absorbs pressure waves. In addition, with a suitable choice of synthetic plastics material, it serves to improve adhesion to the metallic backing plate 1 of the ceramic plates 5 which are surrounded by synthetic plastics material 4.

In the case of a further (not shown) embodiment of the invention, the plates 5 according to Fig. 5, embedded in the synthetic resin 4, may also be replaced by a granulate according to Fig. 3, embedded in the synthetic plastics material 4. By this measure, as well, the absorption of pressure waves can be improved in comparison with the embodiment according to Figs. 1 and 3.

Fig. 6 shows a modification of the embodiment according to Fig. 4. Disposed on the upper face of the multi-layer material which in turn consists of a backing layer 1 and oxide ceramic plates 5 disposed thereon and embedded in synthetic plastics material 4, is a layer of granulate 3, the granulate particles being in turn completely surrounded by a synthetic plastics material 4. Compared with Fig. 4, the embodiment according to Fig. 6 has the advantage that by reason of the angular shape of the granulate 3, the above-described projectile deformation takes place to an even greater extent than when the hard fireproof plates 5 only are used.

The embodiment according to Fig. 7 corresponds to the embodiment according to Fig. 6, a synthetic plastics layer 6 in the form of a plate or film being disposed between the backing layer 1 and the plates 5 which are surrounded by a synthetic plastics material 4. The result is the combined effects of the embodiments shown in Fig. 5 and 6.

In the case of the embodiment according to Fig. 8, there is disposed on the upper face of the projectileproof multi-layer material a top layer 7 which is preferably a woven textile material or a covering of rubber, for example in the form of a rubber sheet.

This top layer may be used not only together with the ceramic plates 5 but also together with a granulate layer according to Fig. 3. Preferably, the top layer 7 is 0.5 to 2 mm thick. Particularly suitable for the layer 7 are fibres or threads of carbon or aramides, for example Kevlar.

In the case of the embodiments of the invention shown in Figs. 9 and 10, finally, the backing layer 1 which as a rule consists of a light metal is replaced by a synthetic plastics panel 8 of corresponding thickness. The result is a further saving on weight.

Particularly suitable synthetic plastics for the panel 8 are again polycarbonate or polyvinyl chloride.

The application of angular particles of hard material (e.g. granulate 3) or oxide ceramic plates 5 on a backing layer result in a considerable saving on weight compared with a conventional metallic armoured plate, particularly because the particles of hard material or oxide ceramic having a lighter specificweightthan armouring metals. By constructing the backing layer 1 from light metal or synthetic plastics material (Figs. 9 and 10), a further weight reduction is achieved. Atthe same time, the particles of hard material or the hard fireproof panels are capable of guaranteeing high ballistic safety despite the saving on weight.

Also the embodiments according to Figs. 5 to 8 can be produced with a backing layer 1 which consists of synthetic plastics material instead of metal.

A preferred material for the manufacture of the backing layer lisa wrought aluminium alloy, a material which can be rolled from pigs into panels.

The particles of hard material may be present in the synthetic plastics material 4 in one or more layers.

In the case of the embodiment of the invention shown in Fig. 11, the panel has three layers, 1,2 and 11, which in this case have a sequence which is reversed to the layering arrangement in the embodiment according to Fig. 6. Athird layer 11 of once again plates 5 of oxide ceramic described hereinabove and embedded in synthetic plastics material 4, is disposed on the layer 2 which has one or more layers of hard particles.

In this case, too, the synthetic resin 4 may be hardened polyurethane or polyvinyl chloride resin.

At the same time, the synthetic resin 4 surrounding the plates 5 provides for a rigid connection to the synthetic resin 4 of the layer 2. Preferably, the plates 5 consist of aluminium oxide.

The plate thickness should be greater than 4 mm and is preferably between 6 and 14, particularly 8 and 12 mm.

In the case of the embodiment shown in Fig. 13, there is between the backing layer 1 and the layer 11 comprising the oxide ceramic plates 5 only one single layer of hard particles 3. Correspondingly, the plates 5 are of greater thickness. If, according to Fig.

12, a plurality of layers of hard particles are present in the layer 2, then the oxide ceramic plates 5 can be kept very thin. The result is a considerable saving on weight in the projectile-proof multi-layer material.

The multi-layer material according to Figs. 12 and 13 is produced initially in the same way as the multi-layer material according to Fig. 3. Synthetic plastics material or adhesive is again applied to the layer 2 containing the particles of hard material.

The oxide ceramic plates 5 are individually placed upon or impressed into the synthetic resin or the adhesive, the synthetic resin or adhesive also ideally penetrating the joints between the plates 5. Then, a further layer of synthetic resin or adhesive is poured on to cover the entire surface of the plates 5 and to penetrate the joints between the plates. Once the synthetic resin has hardened out, the projectileproof multi-layer material is ready for use.

It has been found that the multi-layer material described has considerably improved resistance to projectiles because the pressure wave which arises when the projectiles or the like strike the oxide ceramic plates 5 of the layer 11 is absorbed particularly well by the particles 3 of hard material in the layer 2 so that no oxide ceramic plates 5 become detached in the area adjacent the point of impact. In addition, upon penetration of a projectile or the like into the layer 2, the presence of angularly edged and hard particles 3 which are disposed in the layer 2 results in a deformation and possibly decomposition of the projectile, preventing further penetration into or piercing of the backing layer 1.

Also in the case of the embodiments shown in Figs. 12 and 13, the top layer 7 may be disposed on the upper side of the projectile-proof multi-layer material, in other words on the layer 11.

Fig. 14 shows in section two joined-together armoured panels 21,22 consisting of multi-layer material according to the invention and as illustrated in Fig. 3. At the point of abutment, the armoured panel 21 is of concave construction while the armoured plate 22 has a convex edge to match it. In this way, the armoured panels can be joined together in such a way that one engages over the other. The junction is for practical purposes seamless and the result is a particularly reliable armouring.

Instead of oxide ceramic, the plates 5 mentioned in the foregoing description may also consist of glass carbons. This material has a substantially lower specific weight than oxide ceramic for comparable hardness. The specific weight of glass carbons is around 1.55 g/cc while oxide ceramic (aluminium oxide) has a specific weight of about 3.8 to 4.0 g/cc. Thus, if glass carbons are used as the material for the layer 11, there is a further saving on weight.

In a modified embodiment of the invention, with the multi-layer materials according to Figs. 12 and 13, it is also possible to apply to the topmost layer 11 of oxide ceramic plates 5 also a further layer of glass carbon plates, embedded in synthetic resin.

Claims

1. A projectile-proof multi-layer material characterised by the following construction: a) a backing layer (1) of a material having a specific weight substantially less than that of iron; b) the backing layer (1) is covered by individual adjacently and possibly superimposedly disposed bodies (2) of a material the hardness of which is greater than that of the backing layer (1 ); c) the bodies (2) are embedded substantially all round in a synthetic resin layer (4) which at the same time adheres rigidly to the backing layer (1).

2. A multi-layer material according to Claim 1, characterised in that the backing layer (1) consists of light metal alloy, particularly aluminium alloy, or titanium.

3. A multi-layer material according to Claim 1, characterised in that the backing layer (1) is a synthetic plastics sheet (8), particularly of polycarbonate or polyvinyl chloride.

4. A multi-layer material according to Claim 1,2 or 3, characterised in that particles of hard material, particularly angular silicon carbide and/or boron carbide granulate, are disposed on the backing layer (1).

5. A bullet-proof multi-layer material constructed and arranged substantially as hereinbefore described and as shown in the drawings.

5. A multi-layer material according to Claim 1,2 or 3, characterised in that fireproof plates (5), preferably of oxide ceramic, particularly aluminium oxide, are disposed on the backing layer (1).

6. A multi-layer material according to claim 5, characterised in that between the backing layer (1) and the fireproof plates (5) there is a sheet or film of synthetic plastics material (6), particularly of polycarbonate or polyvinyl chloride.

7. A multi-layer material according to Claim 5 or 6, characterised in that the plates (5) are of rectangular, square or hexagonal shape.

8. A multi-layer material according to claim 7, characterised in that with square plates (5), the edge length is between 18 and 25 and preferably between 25 and 30 mm.

9. A multi-layer material according to one of Claims 1 to 7, characterised in that the particles (3) or plates (5) disposed on the backing layer (1) are embedded substantially on all sides in a polyurethane or polyvinyl chloride resin.

10. A multi-layer material according to Claim 4, characterised in that the granulation of the particles of hard material is about 1 to 5 and preferably 2 to 4 mm.

11. A multi-layer material according to Claim 5, characterised in that the plate thickness is greater than 6 mm and is preferably between 8 and 14 mm.

12. A multi-layer material according to one of the foregoing Claims, characterised in that a backing layer (1) of light metal alloy is at least 6 mm thick.

13. A multi-layer material according to one of the preceding Claims, characterised in that on the upper side of the fireproof plates (5) which is remote from the backing layer (1), angularly edged particles (3) of hard material are embedded in synthetic resin (4).

14. A multi-layer material according to one of Claims 1 to 12, characterised in that it has both an at least single layer (2) of hard particles (3) embedded in synthetic resin (4) and also a layer (11) of oxide ceramic plates (5) embedded in synthetic resin (4).

15. A multi-layer material according to Claim 14, characterised in that the layer (11) is disposed on that side of the layer (2) containing the particles (3) of hard material which is remote from the backing layer (1).

16. A multi-layer material according to one of Claims 1 to 12, characterised in that on the layer (2) of hard particles (3) embedded in synthetic resin (4) there is in addition a layer (11) of glass carbon plates (5) embedded in synthetic resin.

17. A multi-layer material according to one of Claims 1 to 12, characterised in that on the layer (2) of hard particles (3) embedded in synthetic resin (4), there is in addition a combined layer of oxide ceramic and glass carbon plates.

18. A multi-layer material according to one of the preceding Claims, characterised in that the upper face of the material remote from the backing layer (1) is covered by a top layer (7).

19. A multi-layer material according to Claim 18, characterised in that the top layer (7) is a woven fabric or a rubber coating.

Amendments to the Claims have been Filed, and have the following effect: (a) Claims 1-19 above have been deleted.

(b) New Claims have been Filed as follows:

1. A bullet-proof multi-layer material having the following construction: a) a backing layer of a material having a substantially lower specific weight than iron, for example plastics, aluminium alloy or titanium; b) the backing layer is covered by an at least one-layer coating of individual granules of rigid material disposed aiongside and possibly above one another and embedded all round in a layer of synthetic resin, the hardness of the granules being greater than that of the backing layer; c) the backing layer is additionally covered by a layer of oxide ceramic plates embedded in synthetic resin; d) the layer of synthetic resin adheres firmly to the backing layer.

2. A material according to claim 1, wherein the layer of ceramic plates is disposed on that side of the at least one-layer coating which is remote from the backing layer.

3. A material according to claim 1 or claim 2, wherein the surface of the material remote from the backing layer is coated with a covering layer.

4. A material according to claim 3, wherein the covering layer is a woven fabric or a rubber coating.