JP2009543010A - Improved ceramic ballistic panel structure - Google Patents

Abstract

  A ballistic resistant panel made from a plurality of relatively thin ceramic layers and at least one fiber backing layer of high tenacity fibers. The two relatively thin ceramic layers are adjacent to each other, but may be separated by an additional fiber backing layer of high tenacity fibers. The ceramic facing panel of the present invention provides a desirable level of protection against ballistic projectiles. By selecting the number of ceramic layers used in the panel, one can protect against various threat levels. A relatively thin ceramic layer is easier to manufacture than a thick ceramic panel having the same total thickness as the sum of the thicknesses of the plurality of ceramic surface layers. A panel of the present invention having multiple ceramic layers provides substantially the same or greater ballistic resistance as compared to a monolithic panel having substantially the same thickness and composition. Protection against various threat levels is provided by using a desired number of preforms of relatively thin ceramic layers and fiber backings. This provides greater manufacturing flexibility and reduces the inventory of panel structures that need to be stored in order to provide protection against various threat levels.

Description

  The present invention relates to a bulletproof device including a ceramic plate.

  Various types of armor structures have been proposed and used in various applications. These applications include armor for land vehicles and airplanes, bulletproof vests, and stationary objects. In one type of known useful armor structure (eg, in land vehicles and airplanes), a ceramic plate is bonded to a layer of high tenacity fibers. The ceramic plate is designed to face outward in the structure and acts as a primary layer that provides initial protection against ballistic projectiles. These structures are called ceramic faced panels. These panels are generally effective in absorbing and dissipating kinetic energy from projectiles and projectile fragments.

  These types of panels are designed with a specific threat level in mind. As the threat level increases, the thickness of the ceramic plate needs to be increased. However, it is difficult to produce relatively thick ballistic resistant ceramic plates due to increased cost and complexity of the manufacturing process.

  Furthermore, the threat level that a ceramic panel can use is not known at the time of installation. In order to respond to specific threat levels, the armor plate manufacturer or installer has different thicknesses so that specific ceramic panels are available to combat specific types of threats that are recognized. An assortment of various ceramic panels having a must be maintained.

  It would be desirable to provide an improved ceramic surface finish ballistic resistant panel that not only meets the required ballistic requirements, but also meets the above needs.

  The present invention relates to a relatively thin first ceramic layer having an outer surface and an inner surface; a first fiber layer comprising a network of high tenacity fibers and having an outer surface and an inner surface, a first fiber layer An outer surface of the first ceramic layer is adjacent to the inner surface; and a relatively thin second ceramic layer having an outer surface and an inner surface, the outer surface of the second ceramic layer being A ballistic resistant panel comprising: a fiber layer adjacent to an inner surface of the fiber layer;

  The ballistic resistant panel has a total thickness that is substantially the same thickness as the combined thickness of the first ceramic layer, the first fiber layer, the second ceramic layer, and the second fiber layer. Preferably, it has a ballistic resistance substantially equal to or greater than that of a similar ceramic panel structure having only a single ceramic layer backed with.

  In addition, a second fiber layer comprising a network of high tenacity fibers and having an outer surface and an inner surface can also be provided. At this time, the outer surface of the second fiber layer is adjacent to the inner surface of the second ceramic layer, and the inner surface of the second fiber layer is adjacent to the outer surface of the first fiber layer.

  The present invention further includes a relatively thin first ceramic layer having an outer surface and an inner surface; a first fiber layer comprising a network of high tenacity fibers, the outer surface and the inner surface, first fibers The outer surface of the layer is adjacent to the inner surface of the first ceramic layer; a relatively thin second ceramic layer having an outer surface and an inner surface, the outer surface of the second ceramic layer being the first A second fiber layer comprising a network of high tenacity fibers and having an outer surface and an inner surface, wherein the second fiber layer is a first ceramic layer adjacent to the inner surface of the fiber layer; And a second ceramic layer, wherein the outer surface of the second fiber layer is adjacent to the inner surface of the second ceramic layer.

  The present invention can further provide a ceramic surface-finished ballistic resistant panel designed to protect against a specific threat level of ballistic projectiles. Wherein the panel improvements include a relatively thin first ceramic layer having an outer surface and an inner surface; a first fiber layer comprising a network of high tenacity fibers and having an outer surface and an inner surface; An outer surface of the first fibrous layer is adjacent to the inner surface of the first ceramic layer; and a relatively thin second ceramic layer having an outer surface and an inner surface; Making the panel from a structure comprising: an inner surface is adjacent to the outer surface of the first ceramic layer.

  The present invention provides a ballistic resistant panel having a plurality of ceramic layers and at least one (preferably two) fiber backing layers to provide a ceramic facing panel having a desired level of protection. For example, higher protection levels are generally required to protect against armor-piercing bullets rather than rifle bullets. By creating a panel from multiple relatively thin ceramic layers (preferably with a fiber lining on each layer), different threats can be selected by selecting the number of layers of ceramic material used in the panel You can protect yourself from the level. A relatively thin ceramic layer is easier to manufacture than a thick ceramic panel having the same overall thickness as the combined thickness of the ceramic surface layers. Surprisingly, a panel of the present invention having a plurality of ceramic layers provides substantially equal or better ballistic resistance compared to a monolithic panel having substantially the same thickness and composition.

  Furthermore, by producing a relatively thin ceramic plate containing a fiber lining, the armor manufacturer and installer need only stock one type of ceramic panel or one type of ceramic facing panel. . By using the desired number of relatively thin ceramic plates or ceramic facing plates, protection against various ballistic threats can be provided. These multiple plates can be manufactured and assembled in a relatively simple manner that can be used in the field. This allows greater manufacturing flexibility and reduces the overall cost of the structure.

DETAILED DESCRIPTION OF THE INVENTION As previously mentioned, the ballistic resistant panel of the present invention is made from a relatively thin ceramic layer and at least one (preferably multiple) fiber layer of high tenacity fibers. The ceramic material may be in the form of a monolithic structure, or individual smaller ceramic tiles that are bonded together in an appropriate manner (eg, bonded onto a support layer or a fiber layer). It may be a form. Such ceramic layers useful for ballistic resistance applications are known in the art.

  Representative ceramic materials useful in the panels of the present invention include metal nitrides, non-metal nitrides, metal borides, non-metal borides, metal carbides, non-metal carbides, metal oxides, non-metal oxides, and There are mixtures of these. Specific materials include silicon carbide, silicon oxide, silicon nitride, boron carbide, boron nitride, titanium diboride, aluminum oxide, magnesium oxide, and mixtures thereof. Preferred ceramic materials include aluminum oxide, silicon carbide, boron carbide, and mixtures thereof.

  The ceramic layer of the present invention is relatively thin. As used herein, “relatively thin” means that the ceramic layer generally has a thickness of up to about 0.6 inches (15.2 mm), more preferably up to about 0.5. It means that it has a thickness of inches (12.7 mm), and most preferably has a thickness of at most about 0.4 inches (10.2 mm). The thickness of the ceramic layer may range, for example, from about 0.05 to about 0.6 inches (1.3 to 15.2 mm), more preferably from about 0.1 to about 0.5 inches (2 0.5 to 12.5 mm) and most preferably in the range of about 0.1 to about 0.4 inches (2.5 to 10.2 mm).

  The ceramic layer may be unreinforced or may be reinforced with, for example, a fiber material and can be utilized from many sources. For example, the ceramic layer can be bonded, or can be wound with glass fiber, graphite fiber, or the like.

  The ceramic layer may have any areal density [eg, about 0.5 to about 15 psf (2.44 to 73.24 ksm)], with a more preferred areal density of about 1 to about 10 psf (4.88 to 48.48). 83 ksm), and the most preferred areal density is about 2 to about 5 psf (9.77 to 24.41 ksm). For example, a ceramic layer of aluminum oxide having a thickness of about 0.110 inches (2.8 mm) may generally have an areal density of about 2.30 psf (11.23 ksm).

The various layers of the present invention are generally rectangular or square in shape, although other shapes (eg, curved layers) can be used. The ceramic layer has an outer surface and an inner surface.
The present invention includes a relatively thin first ceramic layer. The first ceramic layer is preferably lined with a first fiber layer to be bonded. The ceramic panel structure incorporates at least one other relatively thin ceramic layer. This relatively thin second ceramic layer is the outer facing layer (as well as any additional ceramic layers). The relatively thin second ceramic layer and any subsequent ceramic layers preferably have the same structure as the first ceramic layer. The second ceramic layer can be adhered to the outer surface of the first ceramic layer, and is preferably adhered to the outer surface of the first ceramic layer. In one embodiment, the second ceramic layer is bonded directly to the first ceramic layer. In another preferred embodiment, the second ceramic layer is further lined with a fiber layer [second fiber layer, preferably the same as the fiber layer in the first fiber layer]. However, alternatively, the fibers in the second fiber layer may be different from the fibers in the first fiber layer. If a second fiber layer is used, the outer surface of the second fiber layer is adjacent to the inner surface of the second ceramic layer and the inner surface of the second fiber layer is the first ceramic layer. A second fiber layer is inserted between the relatively thin first ceramic layer and the relatively thin second ceramic layer, adjacent to the outer surface. All layers in the panel are preferably closely bonded.

  If desired, additional ceramic layers and / or additional fiber layers can be used in the panels of the present invention. These additional layers may be adjacent to the second ceramic layer (and thus may extend outside the structure) or may be adjacent to the first fiber layer (and thus It may extend inside the structure). These additional layers are preferably a combination of a relatively thin ceramic layer and another fiber layer. For example, a relatively thin third ceramic layer having an outer surface and an inner surface can be used. The inner surface of the third ceramic layer is preferably adjacent to the outer surface of the second ceramic layer and is preferably adhered to the outer surface of the second ceramic layer. In addition, a third fiber layer having an outer side and an inner side can also be used. The outer surface of the third ceramic layer is preferably adjacent to and adhered to the inner surface of the third ceramic layer and the outer surface of the second ceramic panel. The additional ceramic layer (eg, third layer, fourth layer, etc.) is preferably of the same type as the first ceramic layer or the second ceramic layer (but may be different if necessary). Good). The additional fiber layers (eg, third fiber layer, fourth fiber layer, etc.) are preferably the same as the first fiber layer or the second fiber layer (however, they are different if necessary). Also good).

  In one preferred embodiment, the first ceramic layer and the first fiber layer are preformed into a single unit. Similarly, the second ceramic layer and the second fiber layer are preferably preformed into a single unit. Furthermore, it is preferably extended to any third, fourth or more ceramic layer or fiber backing layer. The preformed layers are preferably bonded together by suitable bonding means. In other preferred embodiments, each of the layers is a separate layer that is consolidated into the final structure.

  Any one of the ceramic layers may be a monolithic structure or may be a plurality of smaller tiles separated by joints. If the two ceramic layers are made from smaller tiles, in a preferred embodiment, the tile joints in one layer are made up by the tile joints in the second layer so that they are in the structure. Are stacked vertically. As a result, the joint of one layer is covered by the solid part of the ceramic layer of the other layer. Alternatively, one ceramic layer may be in the form of a monolithic structure and the other ceramic layer may be in the form of a smaller tile, or both ceramic layers may be in the form of a monolithic structure. If there are more ceramic layers, they can be arranged in the desired configuration.

  According to the present invention, each of the first and second fiber layers includes high tenacity fibers. As used herein, the term “high tenacity fiber” means a fiber having a tenacity of about 7 g / d or greater. These fibers preferably have an initial tensile modulus of at least about 150 g / d and a breaking energy (measured according to ASTM D2256) of at least about 8 J / g. As used herein, the terms “initial tensile modulus”, “tensile modulus”, and “modulus” refer to the elastic modulus for yarns as measured according to ASTM D2256, and to elastomeric and matrix materials. Means the elastic modulus measured according to ASTM D638.

If a third fiber layer or additional fiber layers are used, they preferably also contain high tenacity fibers.
High tenacity fibers preferably have a tenacity of about 10 g / d or greater, more preferably have a tenacity of about 16 g / d or greater, more preferably have a tenacity of about 22 g / d or greater, and about 28 g / d. Most preferably, it has a tenacity of d or greater.

  For the purposes of the present invention, a fiber is an elongated object whose length dimension is much larger than the transverse dimension of width or thickness. Thus, the term “fiber” includes monofilaments, multifilaments, ribbons, strips, staples, and other forms of fibers such as chopped fibers, cut fibers, or discontinuous fibers having a regular or irregular cross section. The term “fiber” includes any of the above fibers or combinations thereof. A yarn is a continuous strand composed of many fibers or filaments.

  The cross section of the fibers useful in the present invention can vary widely. The cross section of the fiber may be circular, flat, or oval. The cross-section may further be a regular or irregular multi-lobe cross-section with one or more regular or irregular lobes protruding from the linear or longitudinal axis of the fiber. The fibers preferably have a substantially circular, flat, or oval cross section, and most preferably have a substantially circular cross section.

  Each of the first and second fiber layers [preferably also additional fiber layers (if incorporated)] includes a network of fibers. The fiber may be in the form of a woven fabric, a knitted fabric, or a non-woven fabric. Preferably at least 50% by weight of the fibers in the fabric are high tenacity fibers, more preferably at least 75% by weight of the fibers in the fabric are high tenacity fibers, and substantially all of the fibers in the fabric are high. Most preferred is tenacity fiber.

  The yarn and fabric used in the present invention may be composed of one or more different high strength fibers. The yarns may be in an essentially parallel arrangement, or the yarns may be twisted, partially overlapped, or intertwined. The fabric used in the present invention may be woven in the machine direction and the transverse direction using yarns having different fibers, or may be woven in other directions.

  High tenacity fibers useful for the yarns and fabrics of the present invention include highly oriented high molecular weight polyolefin fibers, particularly high modulus polyethylene fibers, aramid fibers, polybenzoxazole (PBO) fibers, polybenzothiazole (PBT) fibers, etc. Polybenzazole fibers, polyvinyl alcohol fibers, polyacrylonitrile fibers, liquid crystal copolyester fibers, glass fibers, carbon fibers, basalt fibers and other mineral fibers, rigid rod polymer fibers, and mixtures and blends thereof There is. Preferred high strength fibers useful in the present invention include polyolefin fibers, aramid fibers, polybenzoxazole fibers, and blends thereof. Most preferred are high molecular weight polyethylene fibers, aramid fibers, polybenzoxazole fibers, and blends of two or more thereof.

  U.S. Pat. No. 4,457,985 generally describes such high molecular weight polyethylene fibers and high molecular weight polypropylene fibers, and is hereby incorporated by reference into the disclosure of that patent to the extent that it does not conflict with the present invention. Included in the book. In the case of polyethylene, suitable fibers are polyethylene fibers having a weight average molecular weight of at least about 150,000, preferably polyethylene fibers having a weight average molecular weight of at least about 1 million, more preferably from about 2 million to about It is a polyethylene fiber having a weight average molecular weight of 5 million. Such high molecular weight polyethylene fibers can be spun in solution (see U.S. Pat. Nos. 4,137,394 and 4,356,138), or gel-spun by filament spinning from solution. (See US Pat. No. 4,413,110, German Off. 3,004,699, and British Patent No. 2051667), or polyethylene fibers are produced by a rolling and drawing process (See US Pat. No. 5,702,657). As used herein, the term “polyethylene” contains a small amount of branching or comonomer of less than 5 modifying units per 100 carbon atoms in the main chain, and further about 50 weight % Of one or more polymeric additives [eg, alkene-1-polymers (especially low density polyethylene, polypropylene, polybutylene), copolymers containing monoolefins as primary monomers, oxidized polyolefins, grafted polyolefin copolymers, and poly A mixture of oxymethylene] and polyethylene, or up to about 50% by weight of one or more low molecular weight additives (eg, antioxidants, lubricants, UV screening agents, colorants, and similar materials commonly incorporated). Containing a mixture of polyethylene and polyethylene, It means a linear polyethylene material as.

  High tenacity polyethylene fibers (also called high molecular weight polyethylene fibers or extended chain polyethylene fibers) are preferred as one type of fibers useful for the fiber layer of the present invention. Such fibers are commercially available from Honeywell International, Inc. of Morristown, NJ, USA under the trade name SPECTRA®.

  Various properties can be imparted to these fibers depending on the production method, the draw ratio and draw temperature, and other conditions. The tenacity of the fiber is at least about 7 g / d, preferably at least about 15 g / d, more preferably at least about 20 g / d, more preferably at least about 25 g / d, and most preferably at least About 30 g / d. Similarly, the initial tensile modulus (measured by an Instron tensile tester) of the fiber is preferably at least about 300 g / d, more preferably at least about 500 g / d, and more preferably at least about 1,000 g / d. And most preferably at least about 1200 g / d. These maximum initial tensile modulus and tenacity are generally obtained simply by using solution growth or gel spinning. Many of the filaments have a melting point that is higher than the melting point of the polymer from which they are made. Thus, for example, high molecular weight polyethylenes having molecular weights of about 150,000, about 1 million, and about 2 million generally have a melting point of 138 ° C. in bulk. Highly oriented polyethylene filaments made of these materials have a melting point that is about 7 ° C. to about 13 ° C. higher than this. This somewhat increased melting point indicates higher filament crystal integrity and crystal orientation compared to the bulk polymer.

  Similarly, highly oriented high molecular weight polypropylene fibers having a weight average molecular weight of at least about 200,000 (preferably at least about 1 million, more preferably at least about 2 million) can be used. Such extended chain polypropylene can be made into moderately oriented filaments by the techniques described in the various references cited above, and in particular by the techniques described in US Pat. No. 4,413,110. Because polypropylene is much less crystalline than polyethylene and contains pendant methyl groups, the tenacity values that can be achieved using polypropylene are generally substantially lower than the corresponding values for polyethylene. Accordingly, a suitable tenacity is preferably at least about 8 g / d, more preferably at least about 11 g / d. The initial tensile modulus for polypropylene is preferably at least about 160 g / d, more preferably at least about 200 g / d. The melting point of polypropylene is generally increased several degrees by the orientation process, so that the polypropylene filaments preferably have a main melting point of at least 168 ° C, more preferably at least 170 ° C. Particularly preferred ranges of the above parameters are advantageous because they can provide improved performance to the final article. When fibers having a weight average molecular weight of at least about 200,000 are used in combination with the preferred ranges for the above parameters (modulus and tenacity), advantageously improved performance can be provided in the final article.

  In the case of aramid fibers, suitable fibers made from aromatic polyamides are described in US Pat. No. 3,671,542, which is incorporated herein by reference to the extent not inconsistent with the present invention. ing. Preferred aramid fibers have a tenacity of at least about 20 g / d, an initial tensile modulus of at least about 400 g / d, and a breaking energy of at least about 8 J / g, and particularly preferred aramid fibers have a tenacity of at least about 20 g / d. And a breaking energy of at least about 20 J / g. Most preferred aramid fibers have a tenacity of at least about 23 g / d, a modulus of at least about 500 g / d, and a breaking energy of at least about 30 J / g. For example, poly (p-phenylene terephthalamide) filaments having reasonably high modulus and tenacity values are particularly useful in making ballistic resistant composites. For example, there is Twaron® T2000 commercially available from Teijin Limited having a denier value of 1000. Other examples include Kevlar® 29 with an initial tensile modulus of 500 g / d and tenacity of 22 g / d, as well as 400, 640, and 840 deniers available from DuPont. Kevlar 129 and KM2 are mentioned. In the present invention, commercially available aramid fibers from other manufacturers can also be used. Copolymers of poly (p-phenylene terephthalamide) [eg co-poly (p-phenylene terephthalamide-3,4'-oxydiphenylene terephthalamide)] can also be used. Also useful in practicing the present invention is poly (m-phenylene isophthalamide) fiber, commercially available from DuPont under the trade name Nomex®.

  High molecular weight polyvinyl alcohol (PV-OH) fibers with high tensile modulus are described in US Pat. No. 4,440,711 by Kwon et al., Which patent is incorporated herein by reference to the extent it does not conflict with the present invention. Is disclosed. The high molecular weight PV-OH fiber must have a weight average molecular weight of at least about 200,000. Particularly useful PV-OH fibers have a modulus of at least about 300 g / d, preferably at least about 10 g / d, more preferably at least about 14 g / d, and most preferably at least about 17 g / d, and at least It must have a breaking energy of about 8 J / g. PV-OH fibers having such characteristics can be produced by the method disclosed in US Pat. No. 4,599,267, for example.

  In the case of polyacrylonitrile (PAN), the PAN fibers must have a weight average molecular weight of at least about 400,000. Particularly useful PAN fibers should preferably have a tenacity of at least about 10 g / d and a breaking energy of at least about 8 J / g. PAN fibers having a molecular weight of at least about 400,000, a tenacity of at least about 15-20 g / d, and a breaking energy of at least about 8 J / g are most useful, such fibers are described, for example, in US Pat. No. 4,535. , 027.

  Suitable liquid crystal copolyester fibers for practicing the present invention are disclosed, for example, in US Pat. Nos. 3,975,487, 4,118,372, and 4,161,470.

  Polybenzazole fibers suitable for practicing the present invention include, for example, U.S. Pat. Nos. 5,286,833, 5,296,185, 5,356,584, 5,534,205, And 6,040,050. The polybenzazole fibers are preferably Zylon (registered trademark) polybenzazole fibers commercially available from Toyobo.

  Rigid rod fibers are disclosed, for example, in US Pat. Nos. 5,674,969, 5,939,553, 5,945,537, and 6,040,478. Such fibers are commercially available from Magellan Systems International under the name M5® fibers.

  The fiber layer may be in the form of a woven fabric, in the form of a knitted fabric, in the form of a non-woven fabric, or in various combinations of these in separate layers. If the fabric is a woven fabric, the fabric may be in any desired weave [eg, open weave pattern].

  In one preferred embodiment, the fiber layer is in the form of a non-woven fabric, such as a unidirectionally oriented fiber or a ply of fibers made in felt in a random orientation, and these plies are: Embedded in a suitable resin matrix as is known in the art. Fabrics made from unidirectionally oriented fibers generally form a first fiber layer that is aligned parallel to each other along a common fiber direction, and an angle of 90 ° with the direction of the first fiber. Having a second layer of unidirectionally oriented fibers aligned parallel to each other along a common fiber direction. If the individual plies are unidirectionally oriented fibers, the continuous plies are rotated relative to each other (eg, 0 ° / 90 °, 0 ° / 90 ° / 0 ° / 90 °, or 0 At an angle of ° / 45 ° / 90 ° / 45 ° / 0 °, or at other angles). Such rotated unidirectional alignment is disclosed, for example, in U.S. Pat. Nos. 4,623,574, 4,737,402, 4,748,064, and 4,916,000. Yes.

  A fiber layer is preferably present in the resin matrix. The resin matrix for the fiber ply can be made from various elastomeric materials having the desired properties. In one embodiment, the elastomeric material used in such a matrix has an initial tensile modulus (elastic modulus) of about 6,000 psi (41.4 MPa) or less as measured by ASTM D638. More preferably, the elastomeric material has an initial tensile modulus of about 2,400 psi (16.5 MPa) or less. Most preferably, the elastomeric material has an initial tensile modulus of about 1,200 psi (8.23 MPa) or less. These resin materials are generally thermoplastic, but thermosetting materials are also useful.

Alternatively, the resin matrix can be selected to have a high tensile modulus, such as at least about 1 × 10 ⁶ psi (6895 MPa) when cured. Examples of such materials are disclosed, for example, in US Pat. No. 6,642,159, the disclosure of which is incorporated herein by reference to the extent not inconsistent with the present invention.

  The ratio of resin matrix material to fiber in the composite layer can vary widely depending on the end use. The resin matrix material preferably comprises about 1 to about 98% by weight, more preferably about 5 to 95% by weight, more preferably about 5 to about 40% by weight, based on the total weight of fiber and resin matrix. Is most preferable.

  Various materials including thermoplastic resins and thermosetting resins can be used as the resin matrix. For example, any of the following materials can be used: polybutadiene, polyisoprene, natural rubber, ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, polysulfide polymer, thermoplastic polyurethane, polyurethane elastomer, chlorosulfonated polyethylene, poly Plasticized polyvinyl chloride, butadiene-acrylonitrile elastomers, poly (isobutylene-co-isoprene), polyacrylates, polyesters, polyethers, fluoroelastomers, silicones using chloroprene, dioctyl phthalate or other plasticizers well known in the art Elastomers, thermoplastic elastomers, and copolymers of ethylene. Examples of thermosetting resins include thermosetting resins that are soluble in carbon-carbon saturated solvents (eg, methyl ethyl ketone, acetone, ethanol, methanol, isopropyl alcohol, cyclohexane, ethyl acetone, and combinations thereof). It is done. Thermosetting resins include vinyl ester resins, styrene-butadiene block copolymer resins, diallyl phthalate resins, phenol-formaldehyde resins, polyvinyl butyral resins, and mixtures thereof (see the aforementioned US Pat. No. 6,642,159). Disclosure). Preferred thermosetting resins for polyethylene fiber fabrics include at least one vinyl ester, diallyl phthalate, and optionally a catalyst for curing the vinyl ester resin.

One preferred group of materials are block copolymers of conjugated dienes and vinyl aromatic copolymers. Butadiene and isoprene are preferred conjugated diene monomers. Styrene, vinyl toluene, and t-butyl styrene are preferred conjugated aromatic monomers. Block copolymers incorporating polyisoprene can be hydrogenated to obtain thermoplastic elastomers having saturated hydrocarbon elastomer segments. The polymer is a simple of the type R- (BA) _x (x = 3 to 150) where A is a block from a polyvinyl aromatic monomer; B is a block from a conjugated diene elastomer. It may be a triblock copolymer. A preferred resin matrix is an isoprene-styrene-isoprene block copolymer [eg, Kraton® D1107 isoprene-styrene-isoprene block copolymer commercially available from Kraton Polymer LLC]. Another preferred resin matrix is a thermoplastic polyurethane (eg, an underwater copolymer mixture of polyurethane resins).

  Fillers such as carbon black and silica may be blended into the resin material, and the resin material is increased with oil, or using methods known to rubber engineers, sulfur, peroxide, metal oxide, Alternatively, it can be cured by a radiation curing system. Blends of different resins can also be used.

  The fiber layers of the present invention are generally preferably made by first creating a fiber network and then coating the network with a matrix composition. As used herein, the term “coating” means that individual fibers have a continuous layer of matrix composition surrounding the fibers or a discontinuous layer of matrix composition on the surface of the fibers. It is used in a broad sense to represent a textile network of cases. In the former case, it can be said that the fibers are completely embedded in the matrix composition. The terms “coating” and “impregnation” are used interchangeably herein. Fiber networks can be created in a variety of ways. In the preferred case of a unidirectionally aligned fiber network, a yarn bundle of high tenacity filaments is a collimating comb from a creel guide and a red through guide and one or more spreader bars. And then coated with a matrix material. Collimating combs align the filaments in the same plane and substantially in one direction.

    The matrix resin composition can be applied onto the fiber layer (preferably a unidirectional fiber network) in any suitable form (eg, solution, dispersion, or emulsion). The fiber network coated with the matrix is then dried. A solution, dispersion, or emulsion of matrix resin can be sprayed onto the filament. Alternatively, the filament structure can be coated with an aqueous solution, dispersion, or emulsion by means such as dipping or roll coater. After coating, the coated fiber layer is dried through an oven. The coated fiber network layer (Unitape) is then subjected to sufficient heat to evaporate water or other liquid in the matrix composition. The coated fiber network can then be placed on a carrier web (which can be a paper support or a film support). Alternatively, the fibers can be first placed on a carrier web and then coated with a matrix resin. The support and unitape can then be wound up on a continuous roll by known methods.

    Yarns useful for the fiber layer may be any suitable denier (eg, from about 50 denier to about 3000 denier). The selection is determined in consideration of desired characteristics and cost. Thinner yarns are more costly to manufacture and weave, but can provide better properties (eg, higher ballistic resistance effectiveness per unit weight). The yarn is preferably from about 200 denier to about 3000 denier. More preferably, the yarn is from about 650 denier to about 1500 denier. Most preferably, the yarn is from about 800 denier to about 1300 denier.

  Each of the first fiber layer, the second fiber layer, and the optional additional fiber layer may be made of fibers of the same composition, or of a hybrid layer of fibers having two or more different compositions Form may be sufficient. That is, the one or more fiber layers can be made from at least two layers of different fiber materials (bonded together) or from a mixture of different fiber materials that make up the same layer. You can also.

  The thickness of each fiber layer is preferably the same, but may be different and may vary depending on the particular application, weight, and cost constraints. Typical thicknesses of such fiber layers may range from about 0.1 inch to about 0.8 inch (2.54 mm to 20.32 mm), and from about 0.2 inch to about 0.6 inch ( More preferably, it is in the range of 5.08 mm to 15.24 mm), and most preferably in the range of about 0.3 inches to about 0.5 inches (7.62 mm to 12.70 mm).

  In one preferred embodiment, the first fiber layer is made up of high molecular weight polyethylene fibers, aramid fibers, and / or polybenzoxazole fibers in the form of a unidirectional nonwoven or woven fabric, and the second fiber layer Is made from the same fiber as the first fiber layer in the form of a woven fabric or a unidirectional nonwoven fabric. In another preferred embodiment, the first fiber layer is made up of high molecular weight polyethylene fibers or aramid fibers in the form of a woven or unidirectional nonwoven and the second fiber layer is the first fiber. Made from the same fibers as the layer, in the form of a unidirectional nonwoven or woven fabric.

  Also, the first and second fiber layers (as well as any additional fiber layers) are preferably made from a plurality of plies that are laminated together. The number of plies in each layer depends on the desired areal density, thickness, level of protection, and the like. For example, when the fiber layer is made from high molecular weight polyethylene fibers, aramid fibers, or polybenzoxazole fibers, the number of individual plies can range from about 2 to about 200, and from about 10 to about 150 More preferred is a range, and most preferred is a range of about 50 to about 100. It should be understood that individual plies can be prefabricated into a multi-ply prepreg. For example, if the prepreg is made from 4 plies, the number of plies is reduced to 1/4 of the specified amount.

  The individual plies are further preferably in the form of 2 or 4 unit subassemblies, which in the case of the 2 ply units are cross-plied at 0 ° / 90 °, In this case, the rectangular crossing is made at 0 ° / 90 ° / 0 ° / 90 °. The fiber layer can be made from a plurality of such square orthogonal units.

  The laminate of two or more plies forming the fiber layer of the present invention is preferably produced from a continuous roll of unidirectional prepreg using a continuous cross-ply operation. Such methods are disclosed in US Pat. Nos. 5,173,138 and 5,766,725, which are incorporated herein by reference to the extent not inconsistent with the present invention. Alternatively, the plies can be laminated manually or by any other suitable means. Plies (eg, two plies) are consolidated by applying heat and pressure in a square orthogonal process. Depending on the type of fiber and matrix sheet used, the temperature may range from about 90 ° C. to about 160 ° C., and the pressure may range from about 100 to about 2500 psi (69-17,000 kPa). . “Consolidating” means that the matrix material and the fiber ply are combined into a single layer. Consolidation can be performed by drying, cooling, heating, pressing, or a combination thereof.

  The assembly of the various plies that make up the fiber layer of the present invention may include a rigid assembly or a flexible assembly. Rigid assemblies are typically made, for example, by stacking and consolidating plies in a press under the conditions described above. The flexible assembly is made by loosely stacking the plies (the plies are not joined at this time, or are joined at only one edge or at two or more edges, for example by stitching) Can do.

  In order to facilitate fabrication into the desired shape, one or more plastic films can be incorporated into the fiber layer, for example, so that the different layers slide over each other. These plastic films can generally be adhered to one or both sides of each fiber layer or to one or both sides of each of the two-ply or four-ply compacted prepregs forming the fiber layer. Use any suitable plastic film, such as a film made of polyolefin [eg, linear low density polyethylene (LLDPE) film or ultra high molecular weight polyethylene (UHMWPE) film], polyester film, nylon film, and polycarbonate film be able to. These films can be of any desired thickness. Typical thicknesses are in the range of about 0.1 to about 1.2 mils (2.5-30 μm), more preferably in the range of about 0.2 to about 1 mil (5-25 μm), and Most preferably, it is in the range of about 0.3 to about 0.5 mil (7.5 to 12.5 μm). Most preferred is a film of LLDPE.

  In addition to the fiber layer of high tenacity fibers present in the composite material of the present invention, other layers can also be used. For example, a glass fiber composite and / or a graphite composite can be inserted between two ceramic layers. Such a composite can be produced using a desired resin (for example, a thermosetting epoxy resin). Alternatively, such composite materials may be present elsewhere in the article of the present invention.

In a particularly preferred embodiment of the invention, the ceramic layer is made from aluminum oxide and the fiber layer is made from aramid fibers or high molecular weight polyethylene fibers.
In one embodiment, the first ceramic layer and the first fiber layer are bonded to form a preformed unit. To tie the layers, any suitable means (eg, solid adhesive film, liquid adhesive, etc.) can be used to tie the layers together. An adhesive film using a polyurethane adhesive, an epoxy adhesive, a polyethylene adhesive, or the like is preferable. These layers can be bonded to each other in a suitable press [eg a match-die press] or autoclave. These layers are integrated under appropriate temperature and pressure. For example, if a liquid adhesive is used, the layers can be bonded at room temperature conditions. Alternatively, the layers can be bonded using an adhesive film or liquid adhesive under appropriate pressure and temperature. When heat and pressure are used to bond the layers, the temperature used is about 20 to about 30 ° F. (11.1 to 16.7 ° C.) than the temperature used in the consolidation of the fiber layers described above. ) Preferably low, or preferably about 20 to about 30 ° F. (11.1 to 16.7 ° C.) below the melting point of the fibers used in the fiber backing layer. The pressure may be lower than the pressure used in consolidation of the fiber layer [eg, about 20 to about 500 psi (0.14 to 3.4 MPa)]. If an autoclave is used, the pressure may range, for example, from about 50 to about 250 psi (0.34 to 1.7 MPa).

  Similarly, the second ceramic layer and the second fiber layer (if present) can be bonded in a similar procedure with a similar adhesive. If an additional layer of ceramic and an additional layer of fibers are used, they are also preferably bonded by an adhesive means.

  Various pre-formed layers obtained by combining the first ceramic layer and the first fiber layer together with the second ceramic layer and the second fiber layer are appropriately pressed and stacked together with the sandwiching layer of the adhesive film. be able to. The press may be an autoclave or a match die high pressure press. The adhesive may be the same as or different from the adhesive used to bond the first ceramic layer to the first fiber layer. The stacked preformed layers are preferably integrated under heat and pressure into a consolidated article. To make the entire panel of the present invention, the same pressure and temperature used to make each of the preformed layers can be used, or other pressures and temperatures can be used. .

  Alternatively, all of the layers are bonded together in a single step (eg, stacked in a press and bonded under appropriate heat and pressure) individual layers (ceramic layer, fiber layer, It may be in the form of a ceramic layer, a fiber layer, or the like.

  In order to deepen the understanding of the present invention, examples will be described below, but the present invention is not limited to these examples. The specific methods, conditions, materials, proportions, and data cited to illustrate the principles of the invention are exemplary and should not be considered as limiting the scope of the invention.

Example 1 (comparative example )
A ceramic facing panel was prepared from the ceramic tile. The ceramic tile is an aluminum oxide ceramic having a dimension of 4 × 4 inches (101.6 × 101.6 mm) and a thickness of 0.4 inches (10.16 mm) [AD-commercially available from CoorsTek, Inc. 90]. The ceramic layer had an areal density of 7.41 psf (36.17 ksm). The ceramic was lined with a molded Spectra Shield ™ PCR [2-ply nonwoven composite made from high molecular weight polyethylene fibers (commercially available from Honeywell International)]. This material was a unidirectionally oriented nonwoven structure comprising a matrix resin [20 wt% Kraton D1107 isoprene-styrene-isoprene block copolymer (commercially available from Kraton Polymer LLC)]. This two-ply structure included individual plies squarely orthogonal at 0 ° / 90 °. Spectra polyethylene fiber has a tenacity of 30 g / d, a tensile modulus of 850 g / d, and a breaking energy of 45 g / d.

  The fiber layer contained 148 layers of Spectra shield article and had an areal density of 4 psf (19.5 ksm). These fiber layers are stacked in a 200 ton hydraulic press, preheated at 240 ° F. (116 ° C.) for 10 minutes, to a temperature of 240 ° F. (116 ° C.) and a pressure of 1500 psi (10.3 MPa). For 10 minutes, and then cooled to 150 ° F. (66 ° C.) under pressure to produce a separate consolidated layer. The fiber layer was in the form of a 12 × 12 inch (30.5 × 30.5 cm) sheet.

  A ceramic layer was bonded to a preformed fiber layer of high molecular weight polyethylene fiber at room temperature using a spray adhesive. The ceramic layer was placed in the center of the fiber layer with an adhesive film (approximately the same area as the ceramic layer) sandwiched between the ceramic layer and the fiber layer. The overall density of the obtained panel was 11.41 psf (55.7 ksm).

  The ballistic resistance performance of the panels was tested according to National Institute of Justice (NIJ) Standard 0101.04 Level IV armor. The projectile was an APM 2 armor-piercing bullet with a steel jacket and steel core, 0.50 inches in diameter and 710 grains in weight. The results are shown in Table 1 below.

Example 2
The procedure of Example 1 was repeated except that two ceramic-fiber composite panels of Example 1 were used. Each panel was made as described in Example 1, and then the individual panels were glued together in the same manner as in Example 1.

  The panel had two layers of ceramic and two layers of Spectra Shield PCR nonwoven fabric, which is a high molecular weight polyethylene fiber. This panel was tested for ballistic resistance properties as described in Example 1. The obtained results are shown in Table 1 below.

  As can be seen by comparing Examples 1 and 2, the single layer in combination with the ceramic and consolidated nonwoven failed the test because the bullet penetrated the armor at the indicated exit speed. In contrast, when two layers of ceramic and two layers of consolidated nonwoven were used, the armor passed the test. Thus, the increase in threat speed can be deterred by adding a ceramic layer and there is no need to change the overall composite system of ceramic and lining, and the system is thicker than the combined ceramic and lining. There is no need to replace it with a complex system.

Example 3
A ceramic facing panel was prepared. From an alumina plate (AD-96 commercially available from Cores Tech) having dimensions of 3.985 × 3.985 inches (101.219 × 101.219 mm) and a thickness of 0.110 inches (2.794 mm) A ceramic layer was prepared. The surface density of each ceramic layer was 2.30 psf (11.23 ksm).

  The fiber lining material was Spectra Shield PCRw [4-ply nonwoven composite made from high molecular weight polyethylene fibers (commercially available from Honeywell International)]. This material was a unidirectionally oriented nonwoven structure comprising a matrix resin [16 wt% Kraton D1107 isoprene-styrene-isoprene block copolymer (commercially available from Kraton Polymer LLC)]. This four-ply construction included individual plies squarely orthogonal at 0 ° / 90 ° / 0 ° / 90 °. The fiber had the same properties as in Example 1. The fiber backing was made from a 40-layer Spectra shield product and consolidated by heating and pressurization under the same conditions as in Example 1. The consolidated fiber layer was in the form of a 12 × 12 inch (30.5 × 30.5 cm) sheet. The area density of this layer was 2.00 psf (9.76 ksm).

  The ceramic layer was bonded to the fiber layer using an adhesive film. The adhesive film was a polyether aliphatic polyurethane commercially available from Stevens Urethane having a melting range of 120-140 ° C., 450% elongation at break, and a specific gravity of 1.07 g / cc. A ceramic layer was placed in the center of the fiber layer.

  A second ceramic layer of the same type as the first layer was adhered to the outer surface of the first layer using the same type of adhesive film. The three layers combined were bonded together in an autoclave under the following conditions: 14.7 psf (71.7 ksm) vacuum; 250 psi (1.72 MPa) pressure; 240 ° F. (116 ° C.) temperature; The process is continued for 2 hours; then cooled to 150 ° F. (66 ° C.).

  The ballistic resistance performance of the panels was tested according to National Institute of Justice (NIJ) Standard 0101.04 Level IV armor. The projectile was an M2AP armor bullet with a steel jacket and steel core, 0.30 inches in diameter and 162 grains in weight. The obtained results are shown in Table 2 below.

Example 4 (comparative example )
The procedure described in Example 3 was repeated except that the second ceramic layer was not used. The surface density of the single ceramic layer was 2.8 psf (13.67 ksm), and the overall density of the structure was 4.8 psf (23.43 ksm).

The ballistic resistance performance of the panel was tested as described in Example 1. The slowest bullet that could be fired was 1580 fps (482 mps). This bullet penetrated the panel completely.
Example 5
The procedure of Example 3 was repeated using three bonded ceramic layers of Example 3. The fiber backing layer was made using 42 layers of the 4-ply material of Example 3. The areal density of the fiber layer was 2.15 psf (10.49 ksm).

The structure was bonded under the same conditions as in Example 3.
The ballistic resistance characteristics of the panels were tested as described in Example 3. The obtained results are shown in Table 2 below.

Example 6
The procedure of Example 4 was repeated using four ceramic layers of Example 3. The fiber lining layer was the same as in Example 4.

  The ballistic resistance characteristics of the panels were tested as described in Example 3. The obtained results are shown in Table 2 below.

  Comparing Example 3 and Example 4, the use of a relatively thin additional ceramic layer results in a structure that matches the threat level, but the single layer structure stops for the type of bullet used. It can be seen that it has no resistance. Furthermore, as can be seen from Table 2, the addition of a relatively thin additional ceramic layer to the front of the panel provides a higher level of protection without having to replace the panel with a thicker ceramic / fiber backing panel.

  Accordingly, the present invention provides a ceramic surface finish ballistic resistant panel having a plurality of ceramic layers and at least one (preferably two) fiber backing layers to provide a desired level of protection. I understand. By making a panel from a plurality of relatively thin ceramic layers including at least one fiber backing, the number of ceramic material layers used in the panel can be selected to protect against various threat levels. A relatively thin ceramic layer is easier to manufacture than a thick ceramic panel having the same total thickness as the sum of the thicknesses of the plurality of ceramic surface layers. Surprisingly, a panel of the present invention having multiple ceramic layers provides ballistic resistance that is substantially equal or greater compared to a monolithic panel having substantially the same thickness and composition.

  Protection against various threat levels can be achieved by using a desired number of preforms of relatively thin ceramic layers and fiber backings. This provides greater manufacturing flexibility and reduces the inventory of panel structures that need to be stored in order to provide protection against various threat levels.

  The panels of the present invention are particularly useful for ballistic protection of land vehicles and airplanes. The panels of the present invention are also useful as inserts for stationary devices (such as vests and helmets) in mainland defense applications.

  Although the present invention has been described in considerable detail, it is not necessary to adhere to such details, and further variations and modifications are possible to those skilled in the art, all of which are defined in the claims. It goes without saying that it falls within the scope of the present invention.

Claims (34)

A relatively thin first ceramic layer having an outer surface and an inner surface;
A first fiber layer comprising a network of high tenacity fibers having an outer surface and an inner surface, wherein the outer surface of the first fiber layer is adjacent to the inner surface of the first ceramic layer; A relatively thin second ceramic layer having an outer surface and an inner surface, wherein the inner surface of the second ceramic layer is adjacent to the outer surface of the first ceramic layer, and Two ceramic layers face outwards with respect to the panel;
Ballistic resistant panel including.   A second fiber layer comprising a network of high tenacity fibers and having an outer surface and an inner surface, wherein the outer surface of the second fiber layer is on the inner surface of the second ceramic layer; Adjacent and the second fiber layer is adjacent to the outer surface of the first ceramic layer and the second fiber layer is adjacent to the first ceramic layer and the second ceramic layer. 2. A panel according to claim 1 inserted between the ceramic layers.   The panel has only a single ceramic layer lined with a fiber layer having a total thickness substantially the same as the combined thickness of the first ceramic layer and the second ceramic layer. The panel of claim 1 having a substantially equivalent or greater ballistic resistance compared to the ballistic resistance of a similar ceramic panel structure.   The high tenacity fiber is selected from the group consisting of high molecular weight polyethylene fiber, high molecular weight polypropylene fiber, aramid fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, polybenzazole fiber, polyester fiber, and rigid rod fiber; High tenacity fibers of the type consist of high molecular weight polyethylene fibers, high molecular weight polypropylene fibers, aramid fibers, polyvinyl alcohol fibers, polyacrylonitrile fibers, polybenzazole fibers, polyester fibers, rigid rod fibers, and blends of two or more thereof The panel according to claim 3, which is selected from the group.   The panel of claim 4, wherein the high tenacity fibers have a tenacity of at least about 22 g / d.   The panel of claim 4, wherein the high tenacity fibers have a tenacity of at least about 28 g / d.   The panel according to claim 4, wherein the first fiber layer is in the form of a non-woven network oriented in one direction of fibers and resin matrix.   The panel of claim 7, wherein the resin comprises from about 5 to about 40% by weight of the first fiber layer.   The panel of claim 7, wherein the first fibrous layer comprises a plurality of individual plies oriented relative to each other.   The panel of claim 9, wherein the plies are oriented at an angle of 90 ° with respect to adjacent plies.   The panel of claim 10, wherein the first fiber layer comprises a plurality of prepregs comprising a plurality of fiber plies oriented relative to each other.   The panel of claim 4, wherein the first fiber layer is in the form of a woven fabric comprising a resin matrix.   The panel of claim 4, wherein the first fibrous layer comprises a plurality of individual plies oriented relative to each other, wherein the number of plies ranges from about 2 to about 200.   The panel of claim 4, wherein the first fiber layer comprises fibers selected from the group consisting of high molecular weight polyethylene fibers, aramid fibers, polybenzazole fibers, and blends thereof.   The panel of claim 14, wherein the first fiber layer comprises high molecular weight polyethylene fibers.   The ceramic layer is selected from the group consisting of metal nitride, nonmetal nitride, metal boride, nonmetal boride, metal carbide, nonmetal carbide, metal oxide, nonmetal oxide, and mixtures thereof. The panel of claim 1 comprising a ceramic material.   2. The ceramic layer of claim 1, wherein the ceramic layer comprises a ceramic material selected from the group consisting of silicon carbide, silicon oxide, silicon nitride, boron carbide, boron nitride, titanium diboride, alumina, magnesium oxide, and mixtures thereof. Panel described.   The panel of claim 1, wherein the ceramic layer comprises a ceramic material selected from the group consisting of alumina, silicon carbide, boron carbide, and mixtures thereof.   The panel of claim 3, wherein the ceramic layer comprises alumina.   The panel of claim 1, wherein the thickness of each of the first and second ceramic layers is about 0.05 to about 0.6 inches (1.3 to 15.2 mm).   The panel of claim 1, wherein the thickness of each of the first and second ceramic layers is about 0.1 to about 0.5 inches (2.5 to 12.5 mm).   The first ceramic layer has the same composition as the second ceramic layer, and the fibers in the first fiber layer are the same as the fibers in the second fiber layer. Panel.   The panel according to claim 1, wherein the first ceramic layer and the second ceramic layer are bonded.   24. The panel of claim 23, wherein the first ceramic layer and the first fiber layer are bonded.   And further comprising a relatively thin third ceramic layer having an outer surface and an inner surface, wherein the inner surface of the third ceramic layer is adjacent to the inner surface of the second ceramic layer, and The panel of claim 1, wherein three ceramic layers face outward with respect to the panel. A relatively thin first ceramic layer having an outer surface and an inner surface;
A first fiber layer comprising a network of high tenacity fibers having an outer surface and an inner surface, wherein the outer surface of the first fiber layer is adjacent to the inner surface of the first ceramic layer; Is;
A relatively thin second ceramic layer having an outer surface and an inner surface, wherein the inner surface of the second ceramic layer is adjacent to the outer surface of the first ceramic layer and the second ceramic layer; A second fiber layer comprising a network of high tenacity fibers and having an outer surface and an inner surface, the outer surface of the second fiber layer comprising: Adjacent to the inner surface of the second ceramic layer, the second fiber layer is inserted between the first ceramic layer and the second ceramic layer;
Ballistic resistant panel including.   27. The panel of claim 26, wherein each of the first ceramic layer and the second ceramic layer comprises alumina.   27. The panel of claim 26, wherein each of the first and second fiber layers includes a plurality of prepregs including a plurality of fiber plies oriented relative to each other.   29. The panel of claim 28, wherein each of the first and second fiber layers comprises fibers selected from the group consisting of high molecular weight polyethylene fibers, aramid fibers, polybenzazole fibers, and blends thereof.   30. The panel of claim 29, wherein each of the first and second fiber layers comprises a network of high tenacity fibers and a resin matrix, the resin matrix comprising a styrene-isoprene-styrene block copolymer. An improvement in a ceramic opposed ballistic resistant panel designed to protect against a specific threat level of ballistic projectiles,
A relatively thin first ceramic layer having an outer surface and an inner surface;
A first fiber layer comprising a network of high tenacity fibers having an outer surface and an inner surface, wherein the outer surface of the first fiber layer is adjacent to the inner surface of the first ceramic layer; A relatively thin second ceramic layer having an outer surface and an inner surface, wherein the inner surface of the second ceramic layer is adjacent to the outer surface of the first ceramic layer;
Said improvement comprising producing said panel from a structure comprising:   The panel has only a single ceramic layer lined with a fiber layer having a total thickness substantially the same as the combined thickness of the first ceramic layer and the second ceramic layer. 32. The panel of claim 31, wherein the panel has substantially the same or greater ballistic resistance as compared to the ballistic resistance of a similar ceramic panel structure.   The first fiber layer includes a plurality of prepregs including a plurality of fiber plies oriented with respect to each other, and each of the fiber plies includes a high molecular weight polyethylene fiber, an aramid fiber, a polybenzazole fiber, and these 35. The panel of claim 32, comprising fibers selected from the group consisting of a blend of: wherein each of the ceramic layers comprises a ceramic selected from the group consisting of alumina, silicon carbide, boron carbide, and mixtures thereof. .   The first fiber layer includes a network of high tenacity fibers and a resin matrix, and each of the ceramic layers has a thickness of about 0.1 to about 0.5 inches (2.5 to 12.5 mm). 34. The panel of claim 33, wherein each of the layers is adhered to the adjacent layer.