TW201413210A - Durable soft body armor - Google Patents

Abstract

Ballistic resistant composites having improved durability. More particularly ballistic resistant composites including a protective thermoplastic overlay that enhances composite abrasion resistance while also permitting exploitation of the properties of an underlying binder system.

Description

Durable soft body armor Cross-reference to related applications

This application is a continuation-in-part of the co-pending application Serial No. 13/072,523, filed on March 25, 2011, the disclosure of which is incorporated herein in its entirety. The present application also claims the benefit of the co-pending U.S. Provisional Patent Application Serial No. 61/531,334, the entire disclosure of which is hereby incorporated by reference.

The present invention relates to ballistic resistant composites having improved durability. More particularly, the present invention relates to ballistic resistant composites comprising a protective thermoplastic coating that enhances the abrasion resistance of the composite while also developing the properties of the underlying adhesive system.

Ballistic resistant articles comprising high strength fibers having excellent properties for the emitter are known. Articles (such as bulletproof vests for military equipment, helmets, automotive panels, and structural components) are typically made from fabrics that include high strength fibers. Commonly used high strength fibers include polyethylene fibers, aromatic polyamide fibers such as poly(phenylenediamine terephthalamide), graphite fibers, nylon fibers, glass fibers, and the like. For many applications, such as parts for vests or vests, the fibers can be used in woven or knitted fabrics. For other applications, the fibers can be encapsulated or embedded in a polymeric binder material to form a woven or nonwoven rigid or flexible, flexible multilayer fabric.

The characteristics of soft, flexible body armor are known to vary depending on whether the body armor is made of a woven or nonwoven fabric. Non-woven, unidirectional composite impregnated with polymeric binder material The material is the highest performing material in the body armor industry and is particularly effective for the manufacture of soft personal body armor. Its ballistic performance is generally superior to soft, personal body armor made from woven fabrics. However, it has been believed in the body armor industry that woven fabrics have better durability, especially better surface abrasion resistance, than composites formed from nonwoven fabrics. One known method of improving the abrasion resistance of nonwoven fabrics is by laminating a thin continuous polymeric film, such as a polyethylene film, to the outer surface of the fabric. However, it has been observed that such warp laminated products tend to absorb water at a higher rate than non-laminated products. Alternatively, it is known to coat fabric surfaces with fusible waxes, such as polyethylene waxes, to improve abrasion resistance. Although effective, it was found that the wax undesirably increased the stiffness of the fabric. It has also been discovered that such protective outer surface coatings, whether continuous polymeric films or waxes, tend to affect any underlying chemical resistant coating or environmentally resistant adhesive system beneath the protective outer surface coating. Accordingly, there is a need in the art for a new technology that improves the durability of soft body armor without increasing fabric stiffness while also developing other advantageous fabric properties, such as chemical resistant coatings or environmentally resistant adhesive systems. The present invention provides a method that meets this need in the art.

The present invention provides a ballistic resistant article having at least one thermoplastic cover layer bonded to the outer top surface and/or the outer bottom surface, wherein the at least one thermoplastic cover layer only partially covers the outer surface of the fabric. This has been found to significantly improve the abrasion resistance and durability of the fabric without affecting the chemical resistance and/or environmental resistance of the fabric.

The present invention provides a ballistic resistant article comprising: a) a fiber composite comprising at least one fibrous layer, each fibrous layer comprising a plurality of fibers and a polymeric material on the surface of the fiber and the periphery thereof; the fibrous composite having an outer top a surface and an outer bottom surface; and b) at least one thermoplastic cover layer bonded to the outer top surface and/or the outer bottom surface, wherein the at least one thermoplastic cover layer only partially covers the outer top surface and/or the outer bottom surface.

The present invention also provides a method of making a ballistic resistant article comprising: a) providing a fiber composite comprising at least one fibrous layer, each fibrous layer comprising a plurality of fibers and a polymeric material on and adjacent the surface of the fiber; the fibrous composite Having an outer top surface and an outer bottom surface; b) applying at least one thermoplastic cover layer to the outer top surface and/or the outer bottom surface such that the at least one thermoplastic cover layer only partially covers the outer top surface and/or An outer bottom surface; and c) bonding the at least one thermoplastic cover layer to the outer top surface and/or the outer bottom surface.

The invention further provides a ballistic resistant article comprising: a) a fiber composite comprising at least one fibrous layer, each fibrous layer comprising a plurality of fibers, the fibrous composite having an outer top surface and an outer bottom surface; and b) At least one thermoplastic cover layer bonded to the outer top surface and/or the outer bottom surface, wherein the at least one thermoplastic cover layer only partially covers the outer top surface and/or the outer bottom surface.

The present invention provides a method of adjusting the outer surface of a fiber composite and a resulting ballistic resistant article having improved durability. The fiber composites may be woven or non-woven, and may or may not be impregnated with a polymeric binder material that coats the surface of the fiber component of the composite. The invention is particularly useful for improving the durability of nonwoven fabrics comprising a plurality of layers of fibrous fibers, each fibrous layer comprising a plurality of fibers and a polymeric material disposed on and adjacent the surface of the fibers. The "fiber layer" as used herein may include a single layer of unidirectionally oriented fibers, a plurality of layers of unconsolidated layers of unidirectionally oriented fibers, a plurality of layers of unidirectionally oriented fibers, woven fabrics, a plurality of consolidated weaves. a fabric or any other fibrous structure that has been formed from a plurality of fibers (including felt, Mats, and other structures including randomly oriented fibers. "Layer" describes a substantially planar arrangement. Each fibrous layer has an outer top surface and an outer bottom surface. A "single layer" unidirectionally oriented fiber comprises an arrangement of non-overlapping fibers aligned in a unidirectional, substantially parallel array. This type of fiber arrangement is also known in the art as "unidirectional pre-dip (unitape)" (unidirectional tape). As used herein, "array" describes the juxtaposed arrangement of fibers or yarns in parallel, and "parallel array" describes the ordered parallel arrangement of fibers or yarns. The term "orientation" as used in the context of "oriented fibers" refers to the alignment of fibers that extend relative to the fibers.

For the purposes of the present invention, a "fiber" is an elongate body having a length dimension that is much greater than the transverse dimension of width and thickness. The fiber used in the present invention has a large variation in cross section, and its cross section may be circular, flat or rectangular. Thus, the term "fiber" includes filaments, ribbons, strips, etc. having a regular or irregular cross section, but the fibers preferably have a substantially circular cross section. As used herein, the term "yarn" is defined as a single strand of a plurality of fibers. A single fiber can be formed from only one wire or from a plurality of wires. Fibers formed from only one filament are referred to herein as "single filament" fibers or "monofilament" fibers, and fibers formed from a plurality of filaments are referred to herein as "multifilament" fibers.

The term "fabric" describes a structure that includes one or more layers of fibers that have or are not molded or consolidated. For example, the woven fabric or felt may comprise a single fibrous layer. Nonwoven fabrics formed from unidirectional fibers generally comprise a plurality of layers of fibers stacked and consolidated with one another. As used herein, "single layer" structure refers to a monolithic structure composed of one or more individual layers, wherein the plurality of individual layers have been consolidated with a polymeric binder material in a single unitary structure. "Consolidation" means that the polymeric binder material is combined with the individual fibrous layers into a single unitary layer. Consolidation can occur via drying, cooling, heating, pressure, or a combination thereof. As in the case of wet lamination, heat and/or pressure may not be required since the fibers or fabric layers may just stick together. The term "composite" refers to a combination of fibers and at least one polymeric binder material. As used herein, "complex complex" means a consolidated combination of a plurality of layers of fibrous layers. As described herein, "nonwoven" fabrics include all fabric knots that are not formed by weaving. Structure. For example, the nonwoven fabric can comprise a plurality of unidirectional prepreg tapes that are at least partially coated, stacked/overlapping and consolidated into a single layer, monolithic component, and including (preferably) a polymeric binder composition. Felt or mat of non-parallel, randomly oriented fibers coated. As used herein, "thermoplastic cover" means any thermoplastic material that can be attached to the surface of a fabric or fibrous layer, only partially covering the surfaces. These specifically exclude continuous non-porous films that cover the entire surface of the fabric/fiber layer and environmental factors such as water and organic solvents. However, only one outer fabric/fiber layer surface is coated with a continuous film and the other outer fabric/fiber layer surface is partially covered by the cover layer as described herein, or one outer surface is uncovered and the other outer surface is borrowed. Covered by a cover layer, all of which are within the scope of the invention. Most preferably, the two outer fabric/fiber layer surfaces are partially covered by the cover layer as described herein such that a portion of the underlying polymeric binder material, if present, is exposed through the at least one thermoplastic cover layer. A fiber composite comprising a plurality of fibrous layers has a continuous polymeric film between some or all of the adjacent fibrous layers, which is also within the scope of the invention.

Although it is clearly a non-continuous non-porous film, the thermoplastic cover layer may have any structure without exception as long as it only partially covers the surface to which it is applied. This may for example be a discontinuous thermoplastic web, an ordered discontinuous thermoplastic web, a nonwoven discontinuous fabric, a nonwoven discontinuous gauze, a discontinuously melted powder, an apertured film or a plurality of thermoplastic polymer strips. When a plurality of thermoplastic polymer strips are applied, each strip is a cover layer. The method can be carried out by a thermal lamination method by a calender nip or a flat laminator, or a plurality of methods of wet lamination, including but not limited to, a part of a coating method of applying a resin binder to a fiber. The material is bonded to the fabric/fiber layer. Alternatively, a coating of a discontinuous fusible powder of thermoplastic resin or binder can be applied to the outer surface and then the powder is bonded, melted and/or fused to the surface, such as via a flatbed laminator. These preferred methods are merely non-limiting examples of potential techniques and a comprehensive list of all useful methods that are not intended to be considered as accomplishing the stated objectives. It should be further understood that the fiber layer consolidation and polymer application/binding steps may comprise two separate steps or a single Consolidation/lamination step.

The cover layer can be applied to one or both outer surfaces of the fabric/fiber layer as desired. It can also be applied to a plurality of fibers arranged in an array but which may or may not be considered as a fabric upon coating. As long as the combined cover layer only partially covers the outer top surface and/or the outer bottom surface to which it is applied, a plurality of cover layers may also be applied over the top of each other. The combination of the thermoplastic cover layer and the fabric/fiber layer can generally occur at any stage of the process. For example, when forming a ballistic resistant article comprising a plurality of layers of fibrous layers, the fibrous layers are consolidated using a polymeric binder material, which is most commonly used in the manufacture of ballistic resistant articles, i) in the formation of a plurality of layers of fibrous layers and polymeric binder materials Prior to the consolidation step of consolidation in the composite, or ii) synchronized with the consolidation step of consolidating the plurality of fibrous layers with the polymeric binder material in the composite, or iii) with a plurality of fibrous layers After the consolidation step of the polymeric binder material to solidify in the composite, the thermoplastic cover layer is bonded to the outer fibrous layer of the article.

The fibrous layer and the composite formed therefrom preferably comprise a ballistic resistant composite formed from high strength, high tensile modulus polymeric fibers. Most preferably, the fibers comprise high strength, high tensile modulus fibers for forming ballistic resistant materials and articles. As used herein, "high strength, high tensile modulus fibers" are preferred tensile molds having a preferred tenacity of at least about 7 g/denier or greater, at least about 150 g/denier or greater. The number, and preferably the breaking energy of at least about 8 J/g or greater (measured by ASTM D2256, respectively). As used herein, the term "Danny" refers to a linear density unit equal to the mass of the fiber or yarn per 9000 meters expressed in grams. As used herein, the term "toughness" refers to the tensile stress expressed in force (grams) per unit linear density (Dani) of an uncompressed sample. The "initial modulus" of a fiber is the property of the material that resists deformation. The term "tensile modulus" refers to the ratio of the change in toughness expressed as gram-force/denier (g/d) to the change in strain expressed as the ratio of the original fiber length (in/in).

The fiber-forming polymer is preferably a high strength, high tensile modulus fiber suitable for use in the manufacture of ballistic resistant composites/fabrics. Particularly suitable high strength, high tensile modulus fiber materials suitable for use in forming ballistic resistant composites and articles include polyolefin fibers including high density And low density polyethylene. Particularly preferred are extended chain polyethylene fibers, such as highly oriented, high molecular weight polyethylene fibers, especially ultra high molecular weight polyethylene fibers, and polypropylene fibers, especially ultra high molecular weight polypropylene fibers. Also suitable for aromatic polyamide fibers, especially for aromatic polyamide fibers, polyamide fibers, polyethylene terephthalate fibers, polyethylene naphthalate fibers, extended chain polyvinyl alcohol fibers , extended chain polyacrylonitrile fibers, polybenzoxazole fibers (such as polybenzoxazole (PBO) and polybenzothiazole (PBT) fibers), liquid crystal copolyester fibers and other rigid rod fibers (such as M5® fiber) ). Each of these fiber types is generally known in the art. Also suitable for the manufacture of polymeric fibers are copolymers, block polymers and blends of the above materials.

The best fiber types for ballistic fabrics include polyethylene (especially extended chain polyethylene fibers), aromatic polyamide fibers, polybenzoxazole fibers, liquid crystal copolyester fibers, polypropylene fibers (especially highly oriented extension chains). Polypropylene fibers), polyvinyl alcohol fibers, polyacrylonitrile fibers and other rigid rod fibers (especially M5® fibers). In particular, the most preferred fibers are aromatic polyamide fibers.

In the case of polyethylene, preferred fibers are extended chain polyethylene having a molecular weight of at least 500,000, preferably at least one million and more preferably between two and five million. The extended-chain polyethylene (ECPE) fibers can be grown in a solution spinning process as described in U.S. Patent No. 4,137,394, the disclosure of which is incorporated herein by reference, or in The solution is spun to form a colloidal structure in the manner described in U.S. Patent Nos. 4,551,296 and 5,006,390. A particularly preferred fiber type for use in the present invention is a polyethylene fiber sold under the trademark SPECTRA® from Honeywell International Inc. SPECTRA® fibers are known in the art and are described in, for example, U.S. Patent Nos. 4,623,547 and 4,748,064. In addition to polyethylene, another type of polyolefin fiber that can be used is polypropylene (fiber or tape) such as TIGRIS® fiber available from Milliken & Company of Spartanburg, South Carolina.

Also especially preferred are aromatic polyamines or para-aramid fibers. These are described in, for example, U.S. Patent No. 3,671,542. For example, the poly(p-xylylene terephthalene) filaments available for use are commercially produced by DuPont under the trademark KEVLAR®. Also useful in the practice of the invention are poly(m-xylylenediphenylene isophthalamide fibers) commercially available from DuPont under the trademark NOMEX® and fibers commercially manufactured by Teijin under the trademark TWARON®; commercially Aromatic polyamide fiber manufactured by Kolon Industries, Inc. of Korea under the trademark HERACRON®; aramid fiber SVM ^TM and RUSAR ^TM manufactured commercially by Kamensk Volokno JSC of Russia and commercially produced by Russia the JSC Chim Volokno of manufacture ARMOS ^TM aromatic polyamide fibers.

Suitable polybenzazole fibers for use in the practice of the present invention are disclosed in U.S. Patent Nos. 5,286,833, 5,296,185, 5,356,584, 5,534,205, and the disclosures of which are incorporated herein by reference. 6,040,050. Suitable liquid crystal copolyester fibers for use in the practice of the present invention are disclosed in U.S. Patent Nos. 3,975,487, 4,118,372, and 4,161,470, each incorporated herein by reference. Suitable polypropylene fibers include highly oriented extended chain polypropylene (ECPP) fibers as described in U.S. Patent No. 4,413,110, incorporated herein by reference. Suitable polyvinyl alcohol (PV-OH) fibers are described in, for example, U.S. Patent Nos. 4,440,711 and 4,599,267, each incorporated by reference. Suitable polyacrylonitrile (PAN) fibers are disclosed in, for example, U.S. Patent No. 4,535,027, incorporated herein by reference. Each of these fiber types is generally known and widely available.

M5® fibers are formed from pyridobisimidazole-2,6-diyl (2,5-dihydroxy-p-phenylene) and are manufactured and described by Magellan Systems International of Richmond, Virginia, for example by reference. U.S. Patent Nos. 5,674,969, 5,939,553, 5,945,537, and 6,040,478. Also suitable for all combinations of the above materials, which are commercially available. For example, the fibrous layer may be composed of one or more aromatic polyamide fibers, UHMWPE fibers (eg, SPECTRA® fibers), carbon fibers, and the like. A combination of fiberglass and other lower performance materials.

The fibers can have any suitable denier, such as from 50 to about 3000 denier, more preferably from about 200 to 3000 denier, and more preferably from about 650 to about 2000 denier, and most preferably from about 800 to About 1500 Danny. This choice is determined by the effectiveness of the bulletproof and cost considerations. The manufacture and weaving of finer fibers is more costly, but produces higher ballistic effectiveness per unit weight.

As indicated above, the high strength, high tensile modulus fibers are preferably having a preferred tenacity of about 7 g/denier or greater, a preferred tensile modulus of about 150 g/denier or greater, and about 8 J/g or Larger preferred fracture energy (measured by ASTM D2256, respectively). In a preferred embodiment of the invention, the tenacity of the fibers should be about 15 g/denier or greater, preferably about 20 g/denier or greater, more preferably about 25 g/danny, and still more Preferably, about 30 g/danny or larger, and more preferably about 37 g/danny or larger, especially preferably about 40 g/denier or greater, and more preferably about 45 g/danny Or larger, especially more preferably about 50 g/denier or greater, especially more preferably about 55 g/denier or greater, and most preferably about 60 g/denier or greater. Preferred fibers also have a weight of about 300 g/denier or greater, more preferably about 400 g/denier or greater, more preferably about 500 g/denier or greater, and more preferably about 1,000 g/denier. Or a larger and most preferably a preferred tensile modulus of about 1,500 g/denier or greater. Preferred fibers also have a preferred breaking energy of about 15 J/g or greater, more preferably about 25 J/g or greater, more preferably about 30 J/g, and most preferably about 40 J/. G or greater fracture energy. The high strength properties of the combinations can be obtained by applying known methods. The formation of preferred high strength, extended chain polyethylene fibers is generally discussed in U.S. Patent Nos. 4,413,110, 4,440,711, 4,535,027, 4,457,985, 4,623,547, 4,650,710, and 4,748,064. Such methods including solution growth or colloidal fiber processes are known in the art. Methods of forming each of the other preferred fiber types, including para-aramid fibers, are also generally known in the art, and such fibers are commercially available.

a polymeric binder impregnating the fibrous layer partially or substantially coated with a single fiber of the fibrous layer dimension. Polymeric binder materials are also generally known in the art as "polymeric matrix" materials, and such terms are used interchangeably herein. These terms are generally known in the art and describe a material that binds fibers together by their inherent adhesive properties or after undergoing known thermal and/or pressure conditions. The "polymeric matrix" or "polymeric binder" material may also provide fabrics having other desirable properties such as abrasion resistance and resistance to adverse environmental conditions, and thus, even when the bonding properties are not important, such as in woven fabrics In this case, it may be desirable to coat the fibers with the binder material. If it is desired to combine a plurality of woven fabrics by low pressure lamination or high pressure molding or lamination, it is generally desirable to impregnate or coat the woven fabric with some form of polymeric binder material. Thus, to incorporate a plurality of woven fabrics, the fibers comprising the woven fabric are preferably at least partially coated with a polymeric binder and then followed by a consolidation step similar to that performed on the nonwoven fibrous layer.

Suitable polymeric binder materials include low modulus, elastomeric materials, and high modulus rigid materials. As used throughout, the term tensile modulus means the modulus of elasticity measured for the polymeric binder material by ASTM 2256 for fibers and ASTM D638. Low or high modulus binders can include a variety of polymeric and non-polymeric materials. A preferred polymeric binder includes a low modulus elastomeric material. For the purposes of the present invention, the low modulus elastomeric material has a tensile modulus measured to about 6,000 psi (41.4 MPa) or less according to the ASTM D638 test procedure. Preferably, the low modulus polymer has a tensile modulus of the elastomer of about 4,000 psi (27.6 MPa) or less, more preferably about 2400 psi (16.5 MPa) or less, and more preferably 1200 psi ( 8.23 MPa) or less, and most preferably about 500 psi (3.45 MPa) or less. The glass transition temperature (Tg) of the elastomer is preferably less than about 0 ° C, more preferably less than about -40 ° C, and most preferably less than about -50 ° C. The elastomer also has a preferred elongation at break of at least about 50%, more preferably at least about 100%, and most preferably an elongation at break of at least about 300%.

A variety of materials and formulations with low modulus can be used as polymeric binders. Representative examples include polybutadiene, polyisoprene, natural rubber, ethylene-propylene copolymer, ethylene- Propylene-diene terpolymer, polysulfide polymer, polyurethane elastomer, chlorosulfonated polyethylene, polychloroprene, plasticized polyvinyl chloride, butadiene acrylonitrile elastomer, Poly(isobutylene-co-isoprene), polyacrylate, polyester, polyether, fluoroelastomer, fluorene elastomer, copolymer of ethylene, polyamine (useful for some fiber types), acrylonitrile Diene styrene, polycarbonate, and combinations thereof, as well as other low modulus polymers and copolymers that are curable below the melting point of the fiber. Blends of different elastomeric materials, or blends of elastomeric materials with one or more thermoplastic materials, are also preferred.

Block copolymers of conjugated dienes and vinyl aromatic monomers are especially useful. Butadiene and isoprene are preferred conjugated diene elastomers. Styrene, vinyl toluene and t-butyl styrene are preferred conjugated aromatic monomers. The block copolymer of polyisoprene can be hydrogenated to produce a thermoplastic elastomer having a saturated hydrocarbon elastomer segment. The polymers may be simple triblock copolymers of the type ABA, multiblock copolymers of the type (AB) _n (n=2-10) or type R-(BA) _x (x=3-150) Radiation configuration copolymer; wherein A is a block derived from a polyvinyl aromatic monomer and B is a block derived from a conjugated diene elastomer. Many of these polymers are commercially produced by Kraton Polymers of Houston, TX and described in the publication "Kraton Thermoplastic Rubber", SC-68-81. Also available to the user is a resin dispersion sold under the trademark PRINLIN® and available from Henkel Technologies of Dusseldorf, Germany, as a styrene-isoprene-styrene (SIS) block copolymer. Particularly preferred low modulus polymeric binder polymers include the styrenic block copolymers commercially available from Kraton Polymers under the trademark KRATON®. The most preferred polymeric binder materials include polystyrene-polyisoprene-polystyrene block copolymers sold under the trademark KRATON®.

Also particularly preferred are polymeric binder materials that are resistant to water (especially seawater) dissolution and/or to one or more organic solvents such as diesel or non-diesel gasoline, gun lubricants, petroleum and petroleum-derived organic solvents. . These binder materials help to combine the fiber and fiber layers as well as provide composite materials that are resistant to decomposition by environmental contaminants. polarity The hydrolytically stable polymer exhibits water resistance and resistance to organic solvents while maintaining the required ballistic resistance for an effective ballistic resistant article. Polar polymers are generally resistant to dissolution by non-polar organic solvents, and hydrolytically stable polymers are stable to hydrolysis by water, i.e., resistant to chemical decomposition upon contact with water. Thus, ballistic resistant articles formed by incorporating such polymeric matrix materials retain their ballistic resistance after prolonged exposure to the liquids.

Suitable anti-dissolution polymeric matrix materials preferably include polar modified synthetic rubbers, polar modified diene rubbers, and include styrene-isoprene-styrene (SIS) and styrene-butadiene-styrene (SBS). Polar modified styrene block copolymer, polar vinyl based polymer, polar acrylic polymer, polyvinyl chloride homopolymer, polyvinyl chloride copolymer, polyvinyl chloride terpolymer, polyethylene shrinkage Butyraldehyde, polyvinylidene chloride, polyvinylidene fluoride, polar ethylene vinyl acetate copolymer, polar ethylene acrylic acid copolymer, polyfluorene oxide, thermoplastic polyurethane, nitrile rubber, polychloroprene such as Neoprene (manufactured by DuPont), polycarbonate, polyketone, polyamine, cellulose ester, polyimine, polyester, epoxy resin, alkyd, phenolic resin, polyacrylonitrile, polyether oxime and Its combination. Other polar, hydrolytically stable polymers not illustrated herein are also suitable. Non-polar synthetic rubbers and styrenic block copolymers (such as SIS and SBS) should generally be modified with polar groups, such as by grafting a carboxyl group or adding an acid or alcohol function, or any other polar group, to adequately Oil repellency. For example, the non-polar polymer can be copolymerized with a monomer comprising a carboxylic acid group such as acrylic acid or maleic acid or another polar group such as an amine group, a nitro group or a sulfonic acid group. These techniques are known in the art.

Particularly preferred are polar polymers having a C-C polymer backbone. As indicated herein, polar polymers generally resist dissolution by non-polar organic solvents. Polymers having a C-C-backing chain, such as vinyl-based polymers including, for example, acrylates, ethylene vinyl acetate, polyvinylidene chloride, etc., have a hydrolytically stable molecular structure. Also especially preferred are polar, thermoplastic polyurethanes, especially those which have been formulated to enhance hydrolytic stability. Unlike C-C bonds, urethane linkages and ester linkages are generally susceptible to hydrolytic decomposition. Thus, polymers having such linkages are typically formulated or modified to enhance water repellency and hydrolytic stability. For example, the urethane stability can be improved by copolymerizing a polyurethane with a polyether polyol or an aliphatic polyol component or other components known to improve hydrolytic stability. The primary reaction for the manufacture of polyurethanes is between aliphatic or aromatic diisocyanates and polyols (generally polyethylene glycol or polyester polyols) in the presence of a catalyst. The choice of isocyanate co-reactant can also affect hydrolytic stability. The bulky side chain groups in one or both of the co-reactants also protect the urethane linkage from attack. Polyamines can be produced in a variety of densities and hardnesses by changing the type of monomers used and by modifying other materials to modify their properties or to improve their hydrolytic stability, such as by using water repellents, pH buffers, crosslinkers, and chelating agents. Carbamate.

The thermoplastic polyurethane can be a homopolymer, a copolymer, or a blend of a polyurethane homopolymer and a polyurethane copolymer. These polymers are commercially available. The polyurethanes can generally be obtained in the form of an aqueous solution, dispersion or emulsion wherein the solid component can range from about 20% to 80% by weight, more preferably from about 40% to about 60% by weight, with the balance remaining. The weight is water. Aqueous systems are preferred for ease of use. In particular, the most preferred are polar polyurethanes in the range of soft and rigid materials in the range of tensile modulus ranging from about 2,000 psi (13.79 MPa) to about 8,000 psi (55.16 MPa). Preferred polyurethanes are optimal (but not necessarily) aqueous copolysolvent-free aqueous polyurethane dispersions. These include aqueous anionic polyurethane dispersions, aqueous cationic polyurethane dispersions, and aqueous nonionic polyurethane dispersions. Particularly preferred are aqueous anionic polyurethane dispersions; aqueous aliphatic polyurethane dispersions, and most preferably aqueous anionic aliphatic polyurethane dispersions, all preferred systems A dispersion that does not contain a cosolvent. These include aqueous anionic polyester-based polyurethane dispersions; aqueous aliphatic polyester-based polyurethane dispersions; and aqueous anionic aliphatic polyester-based polyurethane dispersions Liquid, all preferably a dispersion which does not contain a cosolvent. These also include aqueous anionic polyether polyurethane dispersions; aqueous aliphatic polyether-based polyurethane dispersions a liquid; and an aqueous anionic aliphatic polyether-based polyurethane dispersion, all preferably a dispersion without a cosolvent. Similarly preferred are corresponding changes in aqueous cations and aqueous nonionic dispersions (based on polyesters; based on aliphatic polyesters; based on polyethers; based on aliphatic polyethers, etc.). Most preferred are aliphatic polyurethane dispersions having a particularly preferred modulus in the range of about 700 psi or greater, from 700 psi to about 3000 psi at 100% elongation. More preferably, it is an aliphatic polyurethane dispersion having a modulus of about 1000 psi or greater at 100% elongation, and more preferably about 1100 psi or greater. The most preferred polyurethane matrix materials include polar, hydrolytically stable, polyether-based or aliphatic based thermoplastic polyurethanes which are preferred over polyester based polyurethanes, especially An aliphatic, polyether-based anionic polyurethane dispersion having a modulus of 1000 psi or greater, preferably 1100 psi or greater.

Also preferred are fluoropolymers which are compatible with the dissolution, penetration and/or flow of seawater and resistance to dissolution, permeation and/or flow of one or more organic solvents. Fluoropolymers that can be used include fluoropolymers and fluorocarbon resin materials. Fluoropolymers and fluorocarbon resin materials, including fluoropolymer homopolymers, fluoropolymer copolymers or blends thereof, are known in the art and are described, for example, in U.S. Patent Nos. 4,510,301 and 4,544,721. No. 5, 139, 878. Examples of fluoropolymers that may be used include, but are not limited to, homopolymers and copolymers of chlorotrifluoroethylene, ethylene-chlorotrifluoroethylene copolymers, ethylene-tetrafluoroethylene copolymers, fluorinated ethylene-propylene copolymers, Perfluoroalkoxyethylene, polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and copolymers and blends thereof.

As used herein, a copolymer includes a polymer having two or more monomer components. Preferred fluoropolymers include homopolymers and copolymers of polychlorotrifluoroethylene. In particular preferred are the ACLON ^TM and sold under the trademark of Honeywell International Inc.of Morristown, New Jersey of commercially available PCTFE (polychlorotrifluoroethylene homopolymer) materials. The most preferred fluoropolymer or fluorocarbon resin comprises fluorocarbon-modified polymers, especially fluoro-oligomers and fluoropolymers, which are branched from fluorocarbons to conventional polyethers (ie, modified by fluorocarbons). Polyether), polyester (ie fluorocarbon modified polyester), polyanion (ie fluorocarbon modified polyanion) such as polyacrylic acid (ie fluorocarbon modified polyacrylic acid) or polyacrylate (i.e., a fluorocarbon-modified polyacrylate), and a polyurethane (i.e., a fluorocarbon-modified polyurethane) is formed. Such fluorocarbon side chains or perfluoro compounds are generally manufactured by a telomerization method referred to as C ₈ and fluorocarbon. For example, the fluoropolymer or the fluorocarbon resin may be derived from the telomerization of an unsaturated fluorine compound to form a fluorotelomer, wherein the fluorotelomer is further modified to be compatible with a polyether, a polyester, a polyanion, or a polyacrylic acid. The polyacrylate or polyurethane is reacted, and the fluorotelomer is then grafted onto the polyether, polyester, polyanion, polyacrylic acid, polyacrylate or polyurethane. A preferred representative example of such a fluorine-containing carbon polymer is a NUVA® fluoropolymer product commercially available from Clariant International, Ltd., Switzerland. Other fluorocarbon resins, fluorine oligomers, and fluoropolymers based on perfluoroacid and perfluoroalcohol-based side chains are also preferred. Having fluorocarbon side chains of shorter lengths (such as C _6, C ₄ or C ₂₎ of fluoropolymer and fluorocarbon resin are also suitable, such as a Omnova Solutions, Inc.of Fairlawn, Ohio the commercially available fluorochemical PolyFox ^TM drug. A particularly preferred polymeric binder material is a blend of a fluoropolymer or a fluorocarbon resin with at least one non-fluorocarbon-containing polymeric material such as a polyurethane or styrene copolymer.

Polymeric binder materials including nitrile rubber, preferably uncured (uncrosslinked) nitrile rubber, are also preferred because of their environmental resistance. Cured or crosslinked nitrile rubber has a higher modulus than uncured nitrile rubber and, therefore, is harder than uncured materials, which is a problem in some soft body armor applications. Because it achieves the required resistance to water (such as salt water) and organic solvents (such as gasoline), while giving the fabric good peel strength and flexibility, both are a symbol of excellent durability, so nitrile rubber polymers are especially Meet the requirements. Nitrile rubber polymers are a class of unsaturated copolymers of acrylonitrile and butadiene and can be obtained in many different types with different properties. For example, anti-organic solvent (such as oil and gasoline) properties can be controlled and balanced by adjusting the acrylonitrile content of the nitrile rubber relative to the butadiene content using other properties, such as resistance to extreme temperature properties. Due to its polarity, it has a higher acrylonitrile content than nitrile rubber The lower acrylonitrile content of nitrile rubber has better oil and gasoline resistance and also increases tensile strength. Although not as good as polymers with high acrylonitrile content, nitrile rubber with lower acrylonitrile content also exhibits better oil and gasoline resistance, but exhibits excellent flexibility and elasticity, while high acrylonitrile content polymerization The material exhibits greater stiffness and lower flexibility. For soft body armor applications, the nitrile rubber preferably has an acrylonitrile content of from about 15% to about 30% by weight, more preferably from about 20% to about 30% by weight. For hard body armor applications, the nitrile rubber preferably has an acrylonitrile content of from about 31% to about 50% by weight, more preferably from about 40% to about 50% by weight. Nitrile rubber adhesives having a high acrylonitrile content generally have a higher tensile modulus than low acrylonitrile materials and are therefore particularly well suited for rigid body armor applications. Moreover, the crosslinked nitrile rubber has a higher tensile modulus than the uncrosslinked rubber.

Preferred nitrile rubber polymers include nitrile rubber terpolymers including acrylonitrile monomers, butadiene monomers and another monomer component (such as N-methylol acrylamide) or carboxylic acid (A) Acrylic acid). Preferably, the nitrile rubber comprises a carboxylated nitrile rubber (XNBR) terpolymer. Such terpolymers are known in the art and are commercially available, for example, from Dow Reichhold Specialty Latex, LLC. of Research Triangle Park, NC under the trademark TYLAC® 68073. </ RTI> <RTIgt; Another preferred terpolymer includes an acrylonitrile monomer, a butadiene monomer, and N-methylol acrylamide (NMA). An example of a terpolymer of this type is HYCAR® 1572X64 available from Emerald Performance Materials of Akron, Ohio. Other available terpolymers of this type are described, for example, in U.S. Patent No. 5,783,625, the disclosure of which is incorporated herein by reference. The nitrile rubber of the present invention can be hydrogenated as needed to improve durability and environmental resistance. In particular, hydrogenated nitrile rubber (HNBR) has excellent mechanical, thermal oxidation and chemical properties and an excellent operating temperature range. Hydrogenated nitrile rubber is known in the art.

Since the thermoplastic cover only partially covers the outer top surface of the fiber composite and/or The bottom surface, such that a portion of the underlying composite and its polymeric material will be exposed or exposed between the multiple layers of the cover layer. As indicated previously, this exposure through the cover layer allows for the benefit of utilizing a particular selected binder material.

While low modulus polymeric matrix adhesive materials are most useful in forming flexible body armor, such as bulletproof vests, high modulus rigid materials that can be used to form hard body armor articles, such as helmets, are particularly preferred herein. Preferred high modulus rigid materials typically have a higher initial tensile modulus greater than 6,000 psi. Preferred high modulus rigid polymeric binder materials useful herein include polyurethanes (ethers and esters), epoxy resins, polyacrylates, phenolic resins/polyvinyl butyral (PVB) polymers, Vinyl ester polymers, styrene-butadiene block copolymers, and mixtures of polymers such as vinyl esters and diallyl phthalate or phenol formaldehyde and polyvinyl butyral. A particularly preferred rigid polymeric binder material for use in the present invention is a thermoset polymer, preferably soluble in a carbon-carbon saturated solvent such as methyl ethyl ketone and having a measurement by ASTM D638 when cured. of at least about 1x10 ⁶ psi (6895MPa) a high tensile modulus. Particularly preferred rigid polymeric binder materials are those described in U.S. Patent No. 6,642,159, the disclosure of which is incorporated herein by reference. Regardless of the low modulus material or the high modulus material, the polymeric binder may also include fillers (such as carbon black or vermiculite), may be extended with oil, or may be known by sulfur, peroxides, metal oxides or techniques. The radiation curing system hardens. In particular, the preferred one is a polyurethane-based polymeric matrix adhesive in the range of soft and rigid materials having a modulus in the range of from about 2,000 psi (13.79 MPa) to about 8,000 psi (55.16 MPa). .

The rigidity, impact and ballistic resistance of articles formed from the composites of the present invention are affected by the tensile modulus of the polymeric binder polymer of the coated fibers. For example, U.S. Patent No. 4,623,574 discloses the use of a composite having a higher modulus polymer and having a fiber structure of less than about 6,000 psi (41,300 kPa) compared to the same fiber structure without a polymeric binder material. The fiber-reinforced composite of the elastic matrix structure of the tensile modulus has superior ballistic resistance. However, low tensile modulus polymerized binder material polymers also produce lower stiffness Complex. Moreover, in certain applications (especially those in which the composite must act in a bulletproof and structural mode), it is desirable to better combine the ballistic resistance and rigidity.

Thus, the most suitable type of polymeric binder polymer to be used will vary depending on the type of article formed by the composite of the present invention. To achieve a balance of the two properties, a suitable polymeric binder can combine low modulus and high modulus materials to form a single polymeric binder.

The polymeric binder material can be applied simultaneously or sequentially to a plurality of fibers arranged in a web (eg, a parallel array or felt) to form a coated web, applied to the woven fabric to form a coated woven fabric, or in another Arranged to thereby impregnate the fibrous layer with the binder. As used herein, the term "impregnation" is used to mean the same as "buried" and "coated" or otherwise applied with a binder material that diffuses into the fibrous layer and is not simply applied to the surface of the fibrous layer. The polymeric material can also be applied to at least one array of fibers that are not part of the web, and then the fibers are woven into the woven fabric or the nonwoven fabric is prepared following the methods described above. Techniques for forming woven and nonwoven fibrous layers are known in the art.

Although not required, the fibers forming the woven fiber layer are at least partially coated with a polymeric binder and then followed by a consolidation step similar to that performed with the nonwoven fibrous layer. This consolidation step can be carried out to combine the layers of woven woven fibers with one another or to further combine the binder with the fibers of the woven fabric. For example, the plurality of layers of woven fibrous layers need not necessarily be consolidated and may be attached by other means, such as by using conventional adhesives or by stitching.

In general, polymeric binder coatings are required to effectively combine (ie, consolidate) a plurality of layers of nonwoven fibrous layers. The polymeric binder material can be applied to the entire surface area of a single fiber or only to a portion of the surface area of the fiber. Most preferably, a coating of polymeric binder material can be applied to substantially all of the surface area of each individual fiber to form a fibrous layer of the present invention. Where the fibrous layer comprises a plurality of yarns, each of the fibers forming the single yarn is preferably coated with a polymeric binder material.

The polymeric binder material can be applied by any suitable application method and the term "covering" is not intended to limit the method of applying the polymer layer to the filaments/fibers. Use familiar with this technology Any suitable method that is readily determinable applies the polymeric binder material directly to the surface of the fiber, and the binder then diffuses into the fibrous layer in the manner discussed herein. For example, the solution of the polymeric material can be sprayed, extruded or roll coated onto the surface of the fiber in the form of a solution, emulsion or dispersion, wherein a portion of the solution comprises the desired polymer or the polymer and a portion of the solution include The polymer or solvent of the polymers is dissolved or dispersed and then dried to apply the polymeric binder materials. Alternatively, the polymeric binder material can be extruded using generally known techniques, such as by slot die, or by other techniques known in the art, such as direct gravure, Meyer rod, and air knife systems. On the fiber. Another method is to apply a binder material in the form of a liquid, a viscous solid or a suspension or a pure polymer in a fluidized bed to the fibers. Alternatively, the coating can be applied as a solution, emulsion or dispersion contained in a solvent that does not adversely affect the properties of the fiber at the application temperature. For example, the fibers can be transported through a solution of polymeric binder material to substantially cover the fibers and then dried.

In another coating technique, the fibers can be immersed in a bath of solution containing the polymeric binder material dissolved or dispersed in a suitable solvent, and then dried by evaporation or evaporation of the solvent. The method utilizes a polymeric material to preferably at least partially coat each individual fiber, and preferably utilizes a polymeric binder material to substantially coat or encapsulate each individual fiber and cover all or substantially all of the wire/fiber surface area. The impregnation procedure can be repeated as many times as needed to place the desired amount of polymeric material on the fibers.

Other techniques for applying the coating to the fibers can be used, including coating the colloidal fiber precursor as appropriate, such as by passing the colloidal fibers through a solution of the appropriate coating polymer under conditions used to obtain the desired coating. Alternatively, the fibers can be extruded into a fluidized bed of a suitable polymeric powder.

The fibers may be coated with a polymeric binder either before or after the fibers are arranged in one or more layers, or before or after weaving the fibers into a woven fabric. Any fabric weave may be utilized, such as plain weave, crepe weave, oblique weave, satin, using techniques known in the art. The weave method and the twill weave form a woven fabric. Plain weave is most common, in which the fibers are orientated orthogonally at a 0°/90° orientation. Individual fibers of each woven fabric material may or may not be coated with a polymeric binder material prior to or after weaving. In general, the weaving of the fabric is carried out prior to coating the fibers with a polymeric binder, wherein the woven fabrics are thus impregnated with a binder. However, the invention is not intended to be limited by the stage in which the polymeric binder is applied to the fibers, or the manner in which the polymeric binder is applied.

A method of manufacturing a nonwoven fabric is known in the art. In a preferred embodiment herein, the plurality of fibers are arranged in at least one array, generally in the form of a web comprising a plurality of fibers disposed in an array of substantially parallel unidirectional arrays. In a general method of forming a fibrous layer in a nonwoven unidirectional configuration, the fiber bundles are supplied and guided by a creel through a guide and one or more stretching rods into a collimating comb, which are then coated with a polymeric binder material. A typical fiber bundle has from about 30 to about 2000 individual fibers. The stretching rod and the collimating comb disperse and distribute the bundled fibers, and reorganize them in a coplanar manner. The desired fiber dispersion results in a single filament or individual fibers positioned adjacent one another in a single fiber plane, forming a substantially unidirectional parallel array of fibers without the fibers overlapping each other. At this point, cleaning the fibers prior to or during the spreading step can increase and speed up the spreading of the fibers into the parallel array. Fiber cleaning is a method of passing a fiber (or fabric) through a chemical solution that removes any undesirable residual fiber oil (or weaving aid) that has been applied to the fibers during or after manufacture. Fiber cleaning can also increase the bond strength of the polymeric binder material (or subsequent applied protective film) that is subsequently applied to the fibers, and thus may require less binder. By reducing the amount of binder, a greater amount of fiber can be incorporated into the fabric, resulting in a lighter ballistic material with enhanced strength. This also results in increased adhesion to the fiber-increasing emitter, increased stab resistance of the resulting fabric composite, and increased resistance of the composite to repeated impact. After fiber spreading and collimation, the fibers of the parallel array typically comprise from about 3 to 12 fiber ends per inch (1.2 to 4.7 ends/cm), depending on the wire/fiber thickness.

After coating the fibers with the binder material, the coated fibers are formed to include plural An overlapping layer of nonwoven fibers, the nonwoven fibrous layer consolidated into a single layer, a single piece. In a preferred nonwoven fabric structure of the present invention, a plurality of stacked, overlapping unidirectional prepreg tapes are formed, wherein the parallel fibers of each single layer (unidirectional prepreg tape) are oriented relative to the longitudinal fibers of each individual layer. The parallel fibers of each adjacent single layer are positioned orthogonally. The stack of overlapping nonwoven fibrous layers is consolidated under heat and pressure, or by bonding a coating of individual fibrous layers to form a single layer, monolithic component, which is also known in the art as a single layer consolidated mesh. The "consolidation net" describes the consolidation (combination) combination of the fibrous layer with the polymeric matrix/adhesive. The articles of the present invention may also comprise a combination of a combination of a woven fabric and a nonwoven fabric, and a combination of a nonwoven fabric formed from a unidirectional fiber layer and a nonwoven felt fabric.

Most generally, the nonwoven fibrous layer or fabric comprises from 1 to about 6 layers, but may comprise up to about 10 to about 20 layers as desired for different applications. The larger the number of layers, the better the ballistic resistance and the greater the weight. Thus, the number of fibrous layers forming the fibrous layer composite and/or fabric composite or article of the present invention will vary depending on the end use of the fabric or article. For example, in body armor vests for military, in order to achieve the desired formation of 1.0 lbs / square foot or less areal density (4.9kg / m ²⁾ of the composite article, it requires a total of about 100 layers to about 50 layers of a single layer (or layers And wherein the layers may be woven, knitted, felted or nonwoven fabrics (having fibers or other arrangements of parallel orientation) formed from the high strength fibers described herein. In another embodiment, a body armor vest for law enforcement purposes may have a number of layers based on the National Institute of Justice (NIJ) Threat Level. For example, for the NIJ Threat Level IIIA vest, there are 40 layers. For lower levels of NIJ threats, fewer layers can be applied. The present invention allows for the incorporation of a greater number of fibrous layers to achieve the desired degree of ballistic protection without increasing fabric weight compared to other known ballistic resistant structures.

As is generally known in the art, when a single layer of fibers intersects the layers, the direction in which the fibers of one layer are aligned is rotated at an angle relative to the direction in which the fibers of the other layer are aligned, achieving excellent ballistic resistance. Most preferably, the fibrous layers are orthogonally intersecting the tiers at 0° and 90° angles, but adjacent layers may be substantially between about 0° and about the longitudinal direction of the other layer. Align any angle between 90°. For example, a five layer nonwoven structure can have a layer oriented at 0°/45°/90°/45°/0° or at other angles. The unidirectional alignment of the rotations is described in, for example, U.S. Patent Nos. 4,457,985; 4,748,064; 4,916,000; 4,403,012; 4,623,574; and 4,737,402, all of which are incorporated herein by reference. The way is incorporated herein.

A method of consolidating a fibrous layer to form a fibrous layer and a composite is known, such as by the method described in U.S. Patent No. 6,642,159. Consolidation can occur via drying, cooling, heating, pressure, or a combination thereof. As in the case of wet lamination, heat and/or pressure may not be required since the fibers or fabric layers may just stick together. In general, consolidation is accomplished by placing a single fibrous layer on top of the other under conditions sufficient to cause the layers to merge into the heat and pressure of the overall fabric. It can be at a temperature in the range of from about 50 ° C to about 175 ° C, preferably from about 105 ° C to about 175 ° C, and at a pressure in the range of from about 5 psig (0.034 MPa) to about 2500 psig (17 MPa) for about 0.01 seconds. Consolidation is completed in about 24 hours, preferably from about 0.02 seconds to about 2 hours. When heated, the polymeric binder coating may cause sticking or flow when not completely melted. However, in general, if the polymeric binder material (if it is a meltable) is caused to melt, relatively little pressure is required to form the composite, and if the binder material is only heated to the bonding point, a greater pressure is generally required. As is generally known in the art, consolidation can be carried out in a calender apparatus, a flat laminator, a press or in an autoclave. Most commonly, a plurality of orthogonal webs are "sticked" together with the binder polymer and passed through a flat laminator to improve uniformity and bond strength. Moreover, the consolidation and polymer application/bonding steps can include two separate steps or a single consolidation/lamination step.

Alternatively, consolidation can be achieved by molding under heat and pressure in a suitable molding apparatus. Generally, from about 50 psi (344.7 kPa) to about 5,000 psi (34,470 kPa), more preferably from about 100 psi (689.5 kPa) to about 3,000 psi (20,680 kPa), and most preferably about 150 psi (1,034 kPa) to Molding was carried out at a pressure of about 1,500 psi (10,340 kPa). Or may be from about 5,000 psi (34,470 kPa) to about 15,000 psi (103,410 kPa), more preferably Molding is carried out at a higher pressure of from about 750 psi (5,171 kPa) to about 5,000 psi, and more preferably from about 1,000 psi to about 5,000 psi. The molding step can take from about 4 seconds to about 45 minutes. Preferably, the molding temperature is from about 200 °F (~93 °C) to about 350 °F (~177 °C), more preferably from about 200 °F to about 300 °F and most preferably from about 200 °F to about Within the range of 280 °F. The pressure of the fibrous layers and fiber composites of the present invention is generally molded to have a direct effect on the stiffness or flexibility of the resulting molded product. Molding at higher pressures generally produces a harder material up to a certain limit. In addition to the molding pressure, the amount, thickness and composition of the fibrous layers and the type of polymeric binder coating also directly affect the stiffness of the articles formed from the composites.

Although each of the molding and consolidation techniques described herein is similar, each method is different. In particular, molding is generally continuous processing for batch processing and consolidation. Moreover, molding generally involves the use of a mold (such as a forming mold or a counter mold when forming a flat surface), and does not necessarily produce a planar product. Consolidation is typically accomplished in a flatbed laminator, calender nip device, or wet lamination to produce a soft (flexible) body armor fabric. Molding is generally reserved for the manufacture of hard body armor, such as steel sheets. In any method, the suitable temperature, pressure and time will generally depend on the type of polymeric binder coating material, the amount of polymeric binder, the method used, and the type of fiber.

In order to produce a fabric article having sufficient anti-ballistic properties, the total weight of the binder/substrate coating preferably ranges from about 2% to about 50% by weight, more preferably from about 5% to about 30%, and more preferably about 7 From about 10%, and most preferably from about 11% to about 16%, the weight of the fiber and the weight of the coating, with 16% being the best for nonwoven fabrics. Lower binder/matrix content is suitable for woven fabrics where greater than 0 but less than 10% of the weight of the polymer and the weight of the coating are generally optimal. This is not to be considered a limitation. For example, woven phenolic/PVB impregnated woven aramid fabrics are sometimes manufactured at a higher resin content of from about 20% to about 30%, although about 12% is generally preferred.

As indicated above, the thermoplastic cover layer can be, for example, a discontinuous thermoplastic network, ordered Non-continuous thermoplastic web, nonwoven non-continuous fabric, nonwoven non-continuous scrim, discontinuously melted powder, apertured film or a plurality of strips of thermoplastic polymer. Suitable polymers for the thermoplastic cover layer include, non-exclusively, thermoplastic polymers which are non-exclusively selectable from the group consisting of polyolefins, polyamides, polyesters (especially polyethylene terephthalate (PET) And PET copolymer), polyurethane, vinyl polymer, ethylene-vinyl alcohol copolymer, ethylene octane copolymer, acrylonitrile copolymer, acrylic polymer, vinyl polymer, polycarbonate Polystyrene, fluoropolymers and the like, as well as copolymers and mixtures thereof, including ethylene-vinyl acetate copolymer (EVA) and ethylene acrylic acid. Natural and synthetic rubber polymers are also available. Among them, a polyolefin and a polyamide layer are preferred. A preferred polyolefin is polyethylene. Non-limiting examples of polyethylenes that can be used are low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), linear medium density polyethylene (LMDPE), linear very low density. Polyethylene (VLDPE), Linear Ultra Low Density Polyethylene (ULDPE), High Density Polyethylene (HDPE), and copolymers and mixtures thereof. Among them, the most preferred polyethylene is MDPE.

The thermoplastic cover layer is preferably a thermally activated, nonwoven viscous web such as SPUNFAB® available from Spunfab, Ltd, of Cuyahoga Falls, Ohio (trademark registered to Keuchel Associates, Inc.). Protechnic SAof Cernay commercially by the French THERMOPLAST ^TM and HELIOPLAST ^TM mesh, nets and films are also suitable. Among all of the above, the best polyamine network, in particular the SPUNFAB® polyamide mesh. The SPUNFAB® polyamide mesh has a melting point of generally from about 75 ° C to about 200 ° C, but this is not a limitation.

The thermoplastic cover layer is bonded to the fibrous layer using known techniques, such as thermal lamination. In general, lamination is accomplished by placing a single layer on top of the other under conditions sufficient to cause the layers to combine into the heat and pressure of the integral film. The individual layers are placed on the other and then combined by a nip of a pair of heated laminating rolls by techniques known in the art. It can range from about 95 ° C to about 175 ° C, preferably from about 105 ° C to about 175 ° C. Laminating heating is carried out at a temperature within the range of from about 5 psig (0.034 MPa) to about 100 psig (0.69 MPa) for from about 5 seconds to about 36 hours, preferably from about 30 seconds to about 24 hours. .

The thermoplastic cover layer on the surface of the fiber composite is preferably very thin, having a preferred layer thickness of from about 1 μm to about 250 μm, more preferably from about 5 μm to about 25 μm, and most preferably from about 5 μm to about 9 μm. However, it should be understood that the thicknesses are not necessarily a description of the discontinuous mesh. For example, in the presence of materials, SPUNFAB® meshes are several mils thick, but most nets are only as thin as air. These materials are preferably described by their basis weight, for example, SPUNFAB® mesh having a basis weight of 6 grams per square meter (gsm) is especially preferred. The thickness of a single fiber layer corresponds to the thickness of a single fiber. While the thicknesses are preferred, it is to be understood that other thicknesses can be made to meet particular needs and still be within the scope of the invention. The thermoplastic cover layer preferably comprises from about 1% to about 25% by weight total compound, more preferably from about 1% to about 17% by weight of the total composite, based on the weight of the fiber composite and the weight of the cover layer. The best is 1% to 12%. The weight percentage of the polymeric film layer will generally vary depending on the number of fibrous layers and the indicating layer incorporated. For example, the 6 gsm SPUNFAB® layer consists of just over 1% by weight of 500 gsm of final product.

The thickness of the fiber composite corresponds to the thickness of the individual fibers and the number of fibrous layers incorporated into the fabric. A preferred woven fabric has a preferred thickness of from about 25 μm to about 600 μm per layer, more preferably from about 50 μm to about 385 μm, and most preferably from about 75 μm to about 255 μm per layer. A preferred nonwoven fabric (i.e., nonwoven, single layer consolidated web) has a preferred thickness of from about 12 μm to about 600 μm, more preferably from about 50 μm to about 385 μm, and most preferably from about 75 μm to about 255 μm, wherein A single layer consolidated network generally comprises two layers of consolidated layers (i.e., two unidirectional prepreg tapes). While the thicknesses are preferred, it is to be understood that other thicknesses can be made to meet particular needs and still be within the scope of the invention.

Fiber composite according to the present invention having about 20 g ^{/ m 2 (0.004lb / ft 2} (psf)) to about 1000gsm (0.2psf) preferred areal density. The preferred areal density of the fabric/composite of the present invention is in the range of from about 30 gsm (0.006 psf) to about 500 gsm (0.1 psf). The optimum areal density of the fabric/composite of the present invention is in the range of from about 50 gsm (0.01 psf) to about 250 gsm (0.05 psf). The article of the present invention comprising a plurality of layers of fibrous layers stacked and consolidated on top of each other further has from about 1000 gsm (0.2 psf) to about 40,000 gsm (8.0 psf), more preferably from about 2000 gsm (0.40 psf) to about 30,000 gsm. (6.0 psf), more preferably from about 3000 gsm (0.60 psf) to about 20,000 gsm (4.0 psf), and most preferably from about 3750 gsm (0.75 psf) to about 15,000 gsm (3.0 psf). A typical range of composite articles formed into a helmet is from about 7,500 gsm (1.50 psf) to about 12,500 gsm (2.50 psf).

The fabrics of the present invention can be utilized in a variety of applications using known techniques to form a variety of different ballistic resistant articles including flexible, soft body armor articles and rigid, hard body armor articles. For example, suitable techniques for forming bulletproof articles are described in, for example, U.S. Patent Nos. 4,623,574, 4,650,710, 4,748,064, 5,552,208, 5,587,230, 6,642,159, 6,841,492, and 6,846,758. The extent of compatibility herein is incorporated herein by reference.

The following examples are intended to illustrate the invention:

Example 1

A nonwoven web of SPUNFAB® heat activated viscous mesh commercially available from Keuchel Associates, Inc. of Cuyahoga Falls, Ohio, is attached to a consolidation comprising fibers coated with a polar, hydrolytically stable polyurethane polymeric binder material. A single outer surface of a nonwoven fabric based on polyethylene fibers. The viscous web was attached to the fabric by a flat laminator at 225 °F (107.2 °C) and 50 PSI (344.7 kPa).

Example 2

Example 1 was repeated except that SPUNFAB® was attached to the two outer surfaces of the nonwoven composite.

Example 3

Attaching a SPUNFAB® heat activated viscous web to a nonwoven web including the use of a fluorine-containing polymer Consolidation of the polymerized binder material coated fibers, a single outer surface of the polyethylene fiber based nonwoven fabric. The viscous web was attached to the fabric by a flat laminator at 225 °F (107.2 °C) and 50 PSI (344.7 kPa).

Example 4

Example 3 was repeated except that SPUNFAB® was attached to the two outer surfaces of the nonwoven composite.

While the invention has been particularly shown and described with reference to the specific embodiments, It is to be understood that the claims are intended to cover the disclosed embodiments, such alternatives,

Claims (15)

A ballistic resistant article comprising: a) a fiber composite comprising at least one fibrous layer, each fibrous layer comprising a plurality of fibers and a polymeric material on and around the surface of the fiber; the fibrous composite having an outer top surface and an outer bottom a surface; and b) at least one thermoplastic cover layer bonded to the outer top surface and/or the outer bottom surface, wherein the at least one thermoplastic cover layer only partially covers the outer top surface and/or the outer bottom surface. The ballistic resistant article of claim 1, wherein the thermoplastic cover layer is simultaneously bonded to the outer top surface and the outer bottom surface. The ballistic resistant article of claim 1, wherein a portion of the polymeric material is exposed through the at least one thermoplastic cover layer. The ballistic resistant article of claim 1, wherein the cover layer comprises a discontinuous thermoplastic web, an ordered discontinuous thermoplastic web, a nonwoven discontinuous fabric, a nonwoven discontinuous scrim, a discontinuously melted powder, a perforated film or a plurality of strips Thermoplastic polymer strip. The ballistic resistant article of claim 1 wherein the cover layer comprises a discontinuous thermoplastic scrim. The ballistic resistant article of claim 1, wherein the fibrous composite comprises one or more layers of nonwoven fibers. A ballistic resistant article of claim 1 wherein the fibrous composite comprises one or more layers of woven fibers. A ballistic resistant article of claim 1 wherein the fibrous composite comprises a plurality of fibrous layers, wherein a continuous polymeric film is present between each fibrous layer. The ballistic resistant article of claim 1, wherein the polymeric material comprises a hydrolytically stable polar polymer that is resistant to water dissolution and to one or more organic solvents. The ballistic resistant article of claim 1, wherein the polymeric material comprises a fluorine-containing material. The ballistic resistant article of claim 1, wherein the polymeric material comprises from about 7% by weight to about 20% by weight of the fiber composite. A method of making a ballistic resistant article, comprising: a) providing a fiber composite comprising at least one fibrous layer, each fibrous layer comprising a plurality of fibers and a polymeric material on and around the surface of the fiber; the fibrous composite having an outer top surface And an outer bottom surface; b) applying at least one thermoplastic cover layer to the outer top surface and/or the outer bottom surface such that the at least one thermoplastic cover layer only partially covers the outer top surface and/or the outer bottom surface; And c) bonding the at least one thermoplastic cover layer to the outer top surface and/or the outer bottom surface. The method of claim 12, wherein at least one thermoplastic cover layer is simultaneously bonded to the outer top surface and the outer bottom surface. The method of claim 12, wherein the at least one thermoplastic cover is thermally bonded to the outer top surface and/or the outer bottom surface. A ballistic resistant article comprising: a) a fiber composite comprising at least one fibrous layer, each fibrous layer comprising a plurality of fibers, the fibrous composite having an outer top surface and an outer bottom surface; and b) bonded to the outer top At least one thermoplastic cover layer of the surface and/or the outer bottom surface, wherein the at least one thermoplastic cover layer only partially covers the outer top surface and/or the outer bottom surface.