LIGHT-WEIGHT SEMI-RIGID COMPOSITE ANTI-BALLISTIC SYSTEMS WITH ENGINEERED COMPLIANCE AND RATE-SENSITIVE IMPACT RESPONSE

Abstract

Composite anti-ballistic systems having multiple nested sub-laminates manufactured from layers of unidirectional monofilaments made from engineering fibers with anti-ballistic properties embedded in polymer matrix materials and interfacial materials engineered for controlled compliance, deformation, energy release and rate sensitive behavior.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/780,803, filed Mar. 13, 2013, which is incorporated herein in its entirety.

BACKGROUND

Related disclosures are found in U.S. Pat. No. 5,470,062, entitled “COMPOSITE MATERIAL FOR FABRICATION OF SAILS AND OTHER ARTICLES,” which was issued on Nov. 28, 1995; and U.S. Pat. No. 5,333,568, entitled “MATERIAL FOR THE FABRICATION OF SAILS” which was issued on Aug. 2, 1994; and U.S. patent application Ser. No. 13/168,912, filed Jun. 24, 2011 entitled “WATERPROOF BREATHABLE COMPOSITE MATERIALS FOR FABRICATION OF FLEXIBLE MEMBRANES AND OTHER ARTICLES,”; and U.S. patent application Ser. No. 13/197,741, filed Aug. 3, 2011 entitled “SYSTEM AND METHOD FOR THE TRANSFER OF COLOR AND OTHER PHYSICAL PROPERTIES TO LAMINATE COMPOSITE MATERIALS AND OTHER ARTICLES”, the contents of all of which are hereby incorporated by reference for any purpose in their entirety.

This invention relates to providing improved monofilament-related products, methods, and equipment. More particularly, this invention relates to providing systems for design and manufacture of products using the technologies and useful arts herein taught and embodied. Even more particularly, this invention provides improvements in efficiently controlling properties of fabric-related products, including but not limited to: weight, rigidity, penetrability, waterproof-ability, breathability, color, mold-ability, cost, customizability, flexibility, package-ability, etc., including desired combinations of such properties.

In the past, there has been difficulty in achieving desired combinations of such properties, especially with regard to fabric-related products like clothing and shoes, camping and hiking goods, comfortable armor, protective inflatables, etc.

This invention more particularly relates to providing a system for improved composite anti-ballistic systems. More particularly this invention relates to providing a system for composite anti-ballistic systems utilizing composite materials of varying properties.

Current soldier personal protection for anti-ballistic protection is generally either by the common SAPI armor plates or by conventional soft vests. Rigid ceramic SAPI plates provide effective protection, but they limit mobility and are uncomfortable, which distracts soldiers in the field and induces unnecessary rapid fatigue. Additionally, SAPI plates are very susceptible to serious damage due to impacts endemic to soldier's operations in the field; and the damage is difficult to detect, impossible to repair and can result in serious or total degradation in ballistic protection. SAPI plates also have poor protection of closely-spaced multiple hits.

OBJECTS AND FEATURES OF THE INVENTION

A primary object and feature of the present invention is to provide a system overcoming the above-mentioned problem.

Another primary object and feature of the present invention is to provide a system to fine-tune, at desired places on a product, directional control of rigidity/flexibility/elasticity properties.

Yet another primary object and feature of the present invention is to provide products combining extreme light weight with extreme strength.

It is a further object and feature of the present invention to provide such a system providing continuous bulk manufacture of such products and their constituent parts.

Another object and feature of the present invention is to provide adaptability to the various stations of such continuous bulk manufacturing system.

It is a further object and feature of the present invention to provide such a system providing composite anti-ballistic devices.

Another object and feature of the present invention is to provide such a system having multiple nested sub-laminates manufactured from layers of unidirectional monofilaments.

A further object and feature of the present invention is to provide such a system made from engineering fibers with anti-ballistic properties.

It is another object and feature of the present invention to provide such a system comprising polymer matrix materials and interfacial materials engineered for controlled compliance, deformation, energy release and rate sensitive behavior.

A further primary object and feature of the present invention is to provide such a system that is efficient, inexpensive, and handy. Other objects and features of this invention will become apparent with reference to the following descriptions.

SUMMARY OF THE INVENTION

In accordance with a preferred embodiment hereof, this invention provides a laminate including reinforcing elements therein, such reinforcing elements including at least one unidirectional tape having monofilaments therein, all of such monofilaments lying in a predetermined direction within the tape, wherein such monofilaments have diameters less than 20 microns and wherein spacing between individual monofilaments within an adjoining strengthening group of monofilaments is within a gap distance in the range between non-abutting monofilaments up to nine times the monofilament major diameter.

Moreover, it provides such a laminate wherein such monofilaments are extruded. Additionally, it provides such a laminate wherein such reinforcing elements include at least two unidirectional tapes, each having extruded monofilaments therein, all of such monofilaments lying in a predetermined direction within the tape, wherein such monofilaments have diameters less than 20 microns and wherein spacing between individual monofilaments within an adjoining strengthening group of monofilaments is within a gap distance in the range between non-abutting monofilaments up to nine times the monofilament major diameter. Also, it provides such a laminate wherein each of such at least two unidirectional tapes includes larger areas without monofilaments therein and wherein such larger areas comprise laminar overlays comprising smaller areas without monofilaments.

In addition, it provides such a laminate wherein such smaller areas comprise user-planned arrangements. And, it provides such a laminate further comprising a set of water-breathable elements comprising laminar overlays of such smaller areas. Further, it provides such a laminate further comprising a set of other laminar overlays. Moreover, it provides such a laminate wherein a first one of such at least two unidirectional tapes includes monofilaments lying in a different predetermined direction than a second one of such at least two unidirectional tapes.

Additionally, it provides such a laminate wherein a combination of the different predetermined directions of such at least two unidirectional tapes is user-selected to achieve laminate properties having planned directional rigidity/flexibility. Also, it provides such a laminate comprising a three-dimensionally shaped, flexible composite part. In addition, it provides such a product comprising multiple laminate segments attached along peripheral joints. And, it provides such a product comprising at least one laminate segment attached along peripheral joints with at least one non-laminate segment. Further, it provides such a product comprising multiple laminate segments attached along area joints.

Even further, it provides such a product comprising at least one laminate segment attached along area joints with at least one non-laminate segment. Moreover, it provides such a product comprising at least one laminate segment attached along area joints with at least one unitape segment. Additionally, it provides such a product comprising at least one laminate segment attached along area joints with at least one monofilament segment. Also, it provides such a product further comprising at least one rigid element.

In accordance with another preferred embodiment hereof, this invention provides a product wherein such at least one unidirectional tape is attached to such product. In accordance with a preferred embodiment hereof, the present system provides each and every novel feature, element, combination, step and/or method disclosed or suggested by this patent application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagramatic view illustrating at least one composite laminate material according to a preferred embodiment of the present invention.

FIG. 2 shows an enlarged detail view of detail A of FIG. 1 according to the preferred embodiment of FIG. 1.

FIG. 3 shows a data graph, illustrating percent performance vs. number of layers, according to the preferred embodiment of FIG. 1.

FIG. 4 shows a diagramatic view, illustrating flexibility of at least one panel of such at least one composite laminate material, according to the preferred embodiment of FIG. 1.

FIG. 5 shows a diagramatic view, illustrating impact loading of at least one panel of such at least one composite laminate material, according to the preferred embodiment of FIG. 1.

FIG. 6 shows a diagramatic view, illustrating a comparative thickness of at least one panel of such at least one composite laminate material, according to the preferred embodiment of FIG. 1.

FIG. 7 shows a diagramatic view, illustrating intralaminar hybridization, according to the preferred embodiment of FIG. 1.

FIG. 8 shows a diagramatic view, illustrating comingled filaments, according to the preferred embodiment of FIG. 1.

FIG. 9 shows use of sublaminates & interlayers to reduce peak impact loads.

BRIEF GLOSSARY OF TERMS AND DEFINITIONS
Adhesive:       A curable resin used to combine composite materials.
Anisotropic:    Not isotropic; having mechanical and or physical
                properties which vary with direction at a point in the
                material.
aerial weight:  The weight of fiber per unit area, this is often
                expressed as grams per square meter (g/m2).
Autoclave:      A closed vessel for producing an environment of
                fluid pressure, with or without heat, to an enclosed
                object which is undergoing a chemical reaction or
                other operation.
B-stage:        Generally defined herein as an intermediate stage in
                the reaction of some thermosetting resins. Materials
                are sometimes pre cure to this stage, called
                “prepregs”, to facilitate handling and processing
                prior to final cure.
C-stage:        Final stage in the reaction of certain resins in which
                the material is relatively insoluble and infusible.
Cure:           To change the properties of a polymer resin
                irreversibly by chemical reaction. Cure may be
                accomplished by addition of curing (cross-linking)
                agents, with or without catalyst, and with or without
                heat.
Decitex (DTEX): Unit of the linear density of a continuous filament or
                yarn, equal to 1/10th of a tex or 9/10th of a denier
Dyneema ™       Ultra-high-molecular-weight polyethylene fiber by
                DSM
Filament:       The smallest unit of a fiber-containing material.
                Filaments usually are of long length and small
                diameter.
Polymer:        An organic material composed of molecules of
                monomers linked together.
Prepreg:        A ready-to-cure sheet or tape material. The resin is
                partially cured to a B-stage and supplied to a layup
                step prior to full cure.
Tow:            An untwisted bundle of continuous filaments.
UHMWPE:         Ultra-high-molecular-weight polyethylene. A type of
                polyolefin made up of extremely long chains of
                polyethylene. Trade names include Spectra ® and
                Dyneema ®
Unitape         Uni-Directional tape (UD tape) - flexible reinforced
                tapes (also referred to as sheets) having uniformly-
                dense arrangements of reinforcing fibers in parallel
                alignment and impregnated with an adhesive resin.
                UD tapes are typically B-staged and form the basic
                unit of most CT composite fabrics.

DETAILED DESCRIPTION OF THE BEST MODES AND PREFERRED EMBODIMENTS OF THE INVENTION

Referring to FIGS. 1-9, light-weight semi-rigid composite anti-ballistic systems 100 described herein is a pure composite anti-ballistic system based on multiple nested sub-laminates manufactured from layers of unidirectional monofilaments made from engineering fibers with anti-ballistic properties embedded in polymer matrix materials and interfacial materials engineered for controlled compliance, deformation, energy release and rate sensitive behavior. These layers are oriented in multiple directions to distribute the impact loads, control deformation and dissipate impact energy to provide ballistic protection in a form that has sufficient, controlled rigidity under ballistic impact to provide the necessary functions of anti penetration, load spreading, impact energy management and shock management. Such orientation of layers further provide sufficient flexibility and compliance when worn that loss of mobility and range of motion is minimized, and wearer comfort is improved. These improvements enhance combat effectiveness and minimize operator fatigue due to reduced mobility and restriction of range of motion encountered with rigid SAPI plates.

Although the system may be integrated into a system also utilizing a ceramic or metallic component, the pure composite implementation of the system is not susceptible to impact damage like observed in a ceramic SAPI plate and is insensitive to most normal in-service incidental impacts. The system also exhibits superior protection against multiple close spaced hits. Since the system does not absorb significant percentages moisture, the resulting anti-ballistic system does not gain weight or become water-logged due to hydrolysis. The system also is protected from degradation due to flex fatigue, UV radiation and exposure to most agents or chemicals normally encountered.

The system preferably comprises at least one composite anti-ballistic device. Such at least one composite anti-ballistic device preferably comprises improved compliance stretchability and flexibility for higher mobility and less range-of-motion-restriction by preferably using at least one multi-layer, multi-directional sublayer approach.

Such at least one flexible ballistic panel is preferably made from layers of sub-laminates. The sub-laminates of the panel system are preferably manufactured from layers of unidirectional monofilaments of engineering fibers having antiballistic properties, a modulus greater than 1.0×106 psi and a failure strength in excess of 100,000 psi.

Such at least one multi-layer, multi-directional sub-laminate approach preferably uses thin (less than 6 monofilament diameters for conventional monofilaments, less than 0.005″ for ultra thin or nano monofilaments, ropes, yarns fibers) unitape tape layers, alternately preferably intra or interlaminar hybridization of filaments. Such filaments preferably comprise various engineering fibers with a Young's Modulus of over 1 msi and an ultimate tensile strength of more than 100 KSI). Such Engineering fibers preferably include: UBMWPE (available under the trade names Dyneema and Spectra), Aramid (available under the trade names Kevlar and Twaron), PBO fiber under the Zylon name, liquid crystal polymer Vectran, glass fibers such as E and S glass, M5 fibers, carbon and para-aramid under the Technora name. Such Engineered fibers preferably further include nano-filaments, nano-ropes, nano-yarns, nano-tows, nano-powder, and/or nano-film that preferably may be incorporated into the unitape layer, with the unitape and/or applied to the outer surface of the unitape. Such at least one nano-material may be applied to the outer surface of individual monofilaments by nano spray, electron beam deposition, sputtering, vapor deposition, atmospheric plasma deposition, infusion, or as part of polymer coating. Such coating shall preferably comprises a cross linking system with a thermal activation, alternately preferably two part self curing, alternately preferably radiation cured such as E-beam, RF cured, UV cured, or heat cured. The surface of the fibers, the surface of the nano-component and/or the polymer resin may all be provided with chemically reactive functional groups that create a strong chemical bond between the monofilament surface, the nano-component, the short fiber component or the resin, to improve adhesion and enhance energy dissipation.

Individual unitape plies may vary from 1.5-80 g/m̂2 of areal density. The unitape preferably contain one single class of fiber such as Aramid, UHMWPE, glass, etc., alternately preferably contain a combination of classes or styles (same class of fiber but different spec for example), alternately preferably any combination of the above preferably in a predetermined pattern or configuration. The different fiber types may be discrete alternating sets of each material across the width or thickness of the unitape or they can be distributed in a uniform intermixed or comingled configuration. These unitapes may be layered in any combination of materials within each layer of the sub-laminate. Examples are having a sub-laminate made from only one grade of Aramid such as Kevlar or UHMWPE Dyneema monofilament in each unitape in the sub-laminate, or by using one or more different unitapes in the sub-laminate wherein each unitape is made from one type of monofilament. Another example is having a unitape made up of hybrid unitape with multiple fiber types incorporated in each layer but having all the unitape in the sub-laminate made from the same specification of hybrid. Yet another example is the most general where the sub-laminate is made from unitapes with multiple mixes of fiber in the unitape and multiple types of unitape used to make up the sub-laminate.

Individual unitapes within the sub-laminate may alternately preferably also be made from differing fiber areal densities. Hybrid sub-laminates of this kind can provide improved ballistic performance when one of the types of fiber may provide superior protection under some conditions but may not provide adequate protection under another set of conditions. A good example would be the use of UHMWPE monofilaments, which provide excellent anti-ballistic protection under most conditions but are limited in their ability to protect from some impacts by incendiary projectiles that exceed temperature limits of the base polymer. Kevlar or PBO hybrids can improve the ability of the UHMWPE base laminate to protect against the incendiary projectile due to the higher temperature capabilities of the aramid or PBO monofilaments. Using monofilaments of dissimilar properties can also improve the ballistic impact performance because the interactions of the dissimilar monofilaments can generate significant impact energy absorption, shock dissipation and controlled deformations due to the incompatibility of strains between the dissimilar monofilaments.

The minimum number of plies of the sub-laminate can be determined by semi-empirical methods to find the approximate number of plies needed to bring the specific ballistic performance of the sheet up to the level most comparable to the monolithic plate case by obtaining the optimum “lamination effect.” At a certain number of unitape layers the improvement in ballistic performance levels off and the number of plies is determined by the use of a sub-laminate thickness that provides the degree of flex desired, as shown in FIG. 1.

Each unidirectional ply can be oriented in any given in-plane angle. The simplest is a two-direction, cross-ply [0°/90° ] configuration which is easy to fabricate but often does not provide the best ballistic protection nor the best resistance to global panel deformation nor to “back wall deformation.” Back wall deformation is the area directly under the impact area where the laminate is extruded & pushed back into the body of the wearer, which can cause injury or incapacitation. Excessive deformation also degrades the ballistic protection for multi-hit impacts closely spaced. For this reason it is desirable to have a number of angles selected. Three provide some improvement but four angles spaced at the 0°/45°/90°/−45° orientations gives the better performance. Some additional improvement can be obtained by adding another set of ply angles such as at 22.5° increments (0°/22.5 °/45 °/67°/90°/−67°/−45°/−22.5°/0° for example), or at +/−30° or +/−60°. The sub-laminates can be made of stacked repeating sets of these ply groups to build up the desired number of unitape layers in order to achieve the required ballistic performance and flexibility.

The resin content preferably ranges from 1% to 30% of the total areal weight of the unitape with the lower resin contents generally providing better ballistic performance. High and low resin content unitape can be combined in various stacking sequences and layup patterns.

Thin layers of polymer films, non-wovens, and layers of nano-fibers or films preferably can be located at one or more unitape interfaces to improve or modify ballistic performance.

Resin materials may preferably be epoxy base, cyanate ester base, or polyester based resins of varying molecular weight or composition combined with various curing agents to provide the desired matrix properties. Matrix materials preferably may also be thermoplastic polyurethane, alternately preferably block copolyesters, alternately preferably two part polyurethane either with the aromatic or aliphatic isocyanate curing mechanism, alternately preferably ceramics, alternately preferably E-beam deposition polymers, alternately preferably silicones, or others. Resins may preferably be in hot melt, alternately preferably aqueous solutions, alternately preferably solutions with organic or inorganic solvent, alternately preferably water or solvent dispersions, alternately preferably powders, alternately preferably spunbonded films, alternately preferably extruded sheets, alternately preferably cast sheets. The cast or extruded sheets preferably may be homopolymer, alternately preferably a multilayer coextrusion, alternately preferably co-cast onto a carrier, film, paper, or cloth or the film may be unsupported.

Such at least one multilayer, multidirectional sub-laminates preferably comprises unitape of pultruded monofilaments preferably to provide the laminate with a multidirectional-layered network.

The bending stiffness of a ballistic plate or sheet, neglecting effects of transverse strain, preferably is proportional to the section modulus of the plate or sheet, preferably according to the formula:

Section Mod=Z=BD^2/6

Where B is the width and D is the thickness of the plate or sheet.

For comparison purposes only, we set the width normalized to 1 to determine the effects of the sheet or plate thickness on the flexibility of comparable plates and sheets. One inch is a common thickness for composite sheets because it roughly gives 5 lbs/ft2. For the 1″ plate section, the modulus=Z=BD2/6=(1) (1)/6=1/6. Now let examine the effect on flexibility by going thinner, starting at 0.020″ and going up in 0.020″ increments to 0.10″. Z=(1) (1/50)2/6=1/(6) (2500), so the 0.020″=1/2500 of bending stiffness of the 1″ since Z is proportional to the thickness of the panel squared. If t=0.030 the Z=1/1111. If t=0.040 the Z=(1/25)2

For a 1″ stack of the 0.020″ sheet, total flex=to the sum of section modulus: Zeff=Σ2i (Z×50) 1/2500*(50)=1/50; and I=1 to 33.3; Zeff=Σ2i=1/33.3. As one can see from the pattern, the flexibility of a panel made up of sub-laminate of equalizing total thickness, if all sub-laminate thicknesses are the same proportion using this relationship, then we can break the total desired panel thickness into a number of sub-laminates that provide the necessary increase in flexibility. If a thickness of 0.020″ is chosen for the sub-laminate sheet, then the effective stiffness is 1/50 times lower since the bending stiffness of the stack of 50 0.020″ sub-laminates is 50 time less than a monolithic 1″ ballistic plate.

If engineered properly, a panel made from the sub-laminate may have performance ranging from minimal reduction in ballistic performance to actually being higher in ballistic protection than solid rigid plates, while still being flexible. The sub-laminate may be used as discrete sheets with maximum flexibility or they may be lightly bonded together with a thin layer of compliant rate-sensitive dilation material embedded in compliant foam.

Bonding the sub-laminate together in such a way decreases the flexibility of the panel but preferably still allows for a compliant panel, especially if the panel does not need to undergo large deformations as is the case with ballistic plates. It is preferable for a ballistic plate to impart just enough “give” into the panel to provide the necessary level of mobility and comfort.

This is a subjective parameter that depends upon the total thickness of the ballistic panel system, the properties of the monofilament in the sub-laminate and the degree of compliance engineered at the interfaces between the laminates.

Although the sub-laminate system has sub-engineered flexural properties, much of the flexibility is due to the low shear & young's modulus of the viscoelastic dilatory foam materials at the interface bonding the sub-laminate panels into a single panel. Dilatory materials are very rate-sensitive and undergo a transition from highly compliant elastomeric material to highly rigid, solid material. Under impact, the rate of sensitive dilatory layers converts from a soft compliant material into a stiff interlayer that locks up the sub-laminates together so that they act as a solid panel, which means that impact stiffness of a panel increases to close to that of a solid ballistic panel.

The rigidness of the panel under impact spreads the impact loads and maintains the structural integrity of the panel during the impact. Since this is a viscoelastic effect, the rate at which the interlayers transform from soft to rigid can be controlled to manage the impact and spread the force of the impact event over a longer period of time. Spreading the impact load over a longer time period reduces the magnitude of the impact loads, and the load rate preferably can be adjusted to provide optimal load transfer to the individual sub-laminates to provide the highest level of protection from each individual ballistic sub-laminate, as shown in FIG. 1B.

Compliant, viscoelastic interlinear layer of rate-sensitive, higher rate stiffening polymer and polymer foam, as shown in FIG. 1A.

Panel is flexible under normal use due to sub-laminates, as shown in FIG. 4.

Under impact loads the rate-sensitive interlace rigidizes or “freezes” the plate into the equivalent of one-piece panel with no sub-laminate, as shown in FIG. 5.

At least one area of design flexibility on the sub-laminate panels is the ability to select the thickness of the viscoelastic, dilation interlayers. The most effective of the commercial systems are in the form of lightweight foams that allow for the incorporation of relative thick layers with minimal weight increase. The flexibility of the panel is enhanced by the case of thicker compliant layers, which is derivable from a mobility and comfort perspective. Use of thicker compliant layers also increases the thickness of the global panel system. This thickness increase by itself does not generally limit mobility or restrict motion since flexibility is actually enhanced. This increased thickness does significantly increase the effective section modulus of the global panel system during the transient rigid state under impact which can significantly increase the “effective stiffness” of the rigid panel, as shown in FIG. 6.

For example, the one 1″ monolithic panel is broken up into 4 sub-laminates with viscoelastic layers that bring the total thickness of the panel up to 1.5″, in this case the section modulus of the monolithic plate is preferably determined by the formulas:

Section Modulus=(1)²/6 for monolithic

Section Modulus=(1.5)²/6 for sub-laminate

SM|_mono=1/6

SM|_sub=2.25/6

Note: so the effective stiffness of the rigid panel under impact has 2.25 times the stiffness and resistance to deformation.

The “rigidized” compliance layer can act as a core material under impact to improve the structural properties of panel system globally. The viscoelastic layers preferably can also be engineered to provide some progression of load transfer into the individual sub-laminates as the impact event progresses through the panel system which can improve load spread, energy management and contribute to enhanced anti-penetration.

Additionally, applicant's engineered viscoelastic dilation layers preferably provide improved anti-ballistic properties, and improved flexibility for better mobility and increased range of motion without adding excessive weight and/or bulk. This rigidizing, or “freezing,” behavior under impact load preferably provides multiple benefits including: 1. distributing the impact loads, to spread them within the assembly reducing maximum peak loads and associated injury; 2. restricting deformation of the panel in the out-of-plane direction, thus reducing “back wall deformation” that is a measure of how much the panel is deflected inward towards the body of the wearer; 3. increasing the area of the panel used to resist the impact for better energy absorption and shock dissipation; and, 4. allowing improved resistance to projectile penetration by optimizing the progressive response of the panel system to the projectile as it strikes and enters the panel.

The system preferably further comprises hybridization of fiber types by combinations of interlaminar hybridization (different ballistic fiber type layer by layer), alternately preferably intralaminar hybridization (one or more different fiber types within a layer to a predetermined pattern or design), as shown in FIG. 7, alternately preferably comingled (two or more fiber types generally uniformly mixed at the monofilament level), as shown in FIG. 8.

The system alternately preferably comprises hybridization via different fiber types (i.e. Dyneema and Kevlar). Alternately preferably, the system comprises hybridization via different styles, alternately preferably different product forms, alternately preferably different mechanical properties of the same or similar fiber or monofilament (i.e. Dyneema SK 76 hybridized with Dyneema SK90, or Zylon HM hybridized with lower modulus Zylon). This approach is especially useful when significant improvements in one fiber type are offset by reduction in another critical property.

For example, some Dyneema fibers have been drawn to a very fine filament which improves in-plane response but introduces some other limitations which prevent full realization of the fibers anti-ballistic potential. Larger diameter UHMWPE fibers may have lower properties but their thicker filaments combined with a slightly different microstructure can combine to provide higher overall anti-ballistic performance and protection than either one is capable of independently. The system preferably comprises improvement or optimization of the ballistic performance of the monofilaments, preferably by use of fiber surface treatments, surface functionalization, surface coatings, surface grafting and/or deposition with one or more types or layers to optimize the response and integration of the monofilaments to the matrix.

The system preferably further comprises engineered fiber, preferably matrix interfacial properties by use of fiber surface treatments, surface functionalization, surface coatings, surface grafting and/or deposition with one or more types or layers to optimize the response and integration of the monofilaments to the matrix.

The system preferably further comprises incorporation of various rate sensitive polymers and/or non-woven composites of various fibers and polymers, preferably to produce a rate sensitive system, preferably in strategic interlaminar and intralaminar locations for matrix and intralaminar interfaces.

The system preferably further comprises, engineered micro flaws in monofilaments, preferably to promote optimized localized massive simultaneous micro-fracture of filaments, preferably to take advantage of the inherent high strain energy release rate thresholds related to the high Work-Energy-To-Initiate-Fracture properties preferably combined with the high internal hysteresis associated energy dissipation with post failure relaxation with some anti-ballistic monofilaments such as UHMWPE and M5 fibers.

The sub-laminates may be made from a single anti-ballistic monofilament, or multiple fibers may be combined to create a hybrid of many types of monofilaments.

Hybridization may be at the global panel level where sub-laminates are individually manufactured from one type of monofilament but several sub-laminates consisting of different types of monofilament may be used in a desired configuration. At least one non-hybrid sub-laminate (i.e. UHMWPE, Aramid, PBO, glass) along with sub-laminates featuring various forms and/or combinations of fiber classes or hybridization schemes may alternately preferably be used in a configuration.

All of the sub-laminates in a panel may be made from one single class of fiber such as UHMWPE, Aramid, PBO, Glass, etc. if desired. Panels made this way can be either flat or curved to better fit the wearer. If the panels are curved, the sub-laminates may be formed such that they nest together properly when stacked to form the total laminate plate system.

The curved sections preferably are press formed, alternately preferably are autoclave formed, alternately preferably are laminate formed. Additionally, the curved sections are preferably fabricated in one set of sub-laminates, alternately preferably are fabricated individually and then assembled.

Upon reading the teachings of this specification, those skilled in the art will now appreciate that, under appropriate circumstances, considering such issues as use environment, future technologies, cost, etc., other uses of the composite system, such as, for example, rigid pates made from same materials systems where flexibility is not desired, blast protection, containment of explosive failure of rotating machinery, containment of jet engine and other gas turbine engine compressor blade failures, sporting good protection, crash protection, reinforcement of masonry, brick and concrete structure and buildings to protect them from blast or seismic damages and secondary collapse or failure, vehicle, aircraft armor, use as a flexible “cloth” replacement for conventional ballistic soft vests, etc., may suffice.

The flexible sub-laminate preferably makes a very high performance option as a replacement for current vest fabrics for flexible vests and body armor. The composite sub-laminates preferably have superior anti-ballistic properties, and load spreading relative to conventional cloth technologies and preferably have the further advantage that they do not absorb moisture and become liquid saturated, and the fiber monofilaments are fully encapsulated and protected so they are protected from abrasion, chaffing, flex fatigue and environmental degradation due to sweat, fluids, chemicals, and UV or visible radiation.

In vest applications it is generally advantageous to select the sub-laminate thickness that gives the highest degree of anti-ballistic protection with the thinnest overall laminate thickness, and the maximum number of the thinnest unitapes preferably oriented in as many angular directions as is possible consistent with cost and production throughput constraints. Further, the use of shear thickening matrix and interlaminate layers preferably may be used to improve impact properties.

A thin, compliant, rate-sensitive layer or layers, about 1-10 microns in thickness, preferably can be incorporated into the sub-laminate. This layer or layers can be a viscoelastic material with high loss factor for absorbing, damping, and dissipating impact forces and energy release from the impact while also adding flexibility to the sub-laminate. Strategically locating interlayers preferably can substantially enhance load spread and energy management by tailoring the impact impulse as was previously discussed, and as shown in FIG. 9.

This material is especially useful for many aircraft applications since it can be desirable to have a semi-flexible material, for example, in the nacelle armoring the compressor blades of the engine. The flexibility of the armor prevents over-stiffening the nacelle, which could promote premature fatigue of the engine support structure, but has enough rigidity during the impact of the failed compressor blades that it can retain structural integrity while simultaneously containing the blade fragments.

This material is also an ideal solution for reinforcement of masonry brick, concrete structure and buildings to protect them from blast or seismic damages, and secondary collapse or failure by laminating one or more sub-laminate sheets to the walls or ceilings of the structures using an integrated gel style curing adhesive layer or via a sprayed or brushed on toughened adhesive or a combination of both types of bonding agents.

The material preferably can be transparent, opaque, translucent, colored, printed or textured for decorative architectural effects or to add camouflage, IR control or other Low Observable finishes and textures. Additionally, the material preferably can incorporate a weatherable outer surface layer that has an environmental control function such as solar reflectivity or UV blocking for insulation or energy efficiency as a secondary feature.

Although applicant has described applicant's preferred embodiments of this invention, it will be understood that the broadest scope of this invention includes modifications such as diverse shapes, sizes, and materials. Such scope is limited only by the below claims as read in connection with the above specification. Further, many other advantages of applicant's invention will be apparent to those skilled in the art from the above descriptions and the below claims.

Claims

1. An antiballistic composite comprising:

(a) multiple sub-laminate layers; and

(b) viscoelastic dilatory material distributed as interlayers between said sub-laminate layers;

wherein said viscoelastic dilatory material converts from soft compliant material to stiff interlayers when said composite is subjected to impact.

2. The composite of claim 1, wherein said viscoelastic dilatory material comprises a rate-sensitive high-rate stiffening polymer or a polymer foam.

3. The composite of claim 1, wherein said viscoelastic dilatory material bonds each of said multiple sub-laminate layers together into a single panel.

4. The composite of claim 1, wherein said interlayers are about 1-10 microns in thickness.

5. The composite of claim 1 comprising at least ten sub-laminate layers.

6. The composite of claim 1, wherein each sub-laminate layer comprises at least one unidirectional tape comprising parallel monofilaments embedded in a resin.

7. The composite of claim 6, wherein said monofilaments have diameters less than about 20 microns and wherein spacing between individual monofilaments within an adjoining strengthening group of monofilaments is within a gap distance in the range between non-abutting monofilaments up to about nine times the monofilament major diameter.

8. The composite of claim 6, wherein said monofilaments have modulus greater than 1.0×106 psi and failure strength greater than greater than 1.0×105 psi.

9. The composite of claim 6 comprising two unidirectional tapes oriented as a cross-ply, wherein the parallel monofilaments present in one tape are 90° relative to the parallel monofilaments present in the other tape.

10. The composite of claim 6, wherein said tapes total four in a ply group, and wherein the parallel monofilaments within each of said four tapes have relative orientation of 0°/45°/90°/−45°.

11. The composite of claim 6, wherein said tapes total nine in a ply group, and wherein the parallel monofilaments within each of said nine tapes have a relative orientation of 0°/22.5°/45°/67°/90°/−67°/−45°/−22.5°/0°.

12. The composite of claim 6, wherein said monofilaments are extruded or pultruded.

13. The composite of claim 6, wherein said resin comprises from 1% to 30% of the total areal weight of said tape.

14. An antiballistic device comprising at least one antiballistic composite, said antiballistic composite comprising:

(a) multiple sub-laminate layers; and

(b) viscoelastic dilatory material distributed as interlayers between said sub-laminate layers;

wherein said viscoelastic dilatory material converts from soft compliant material to stiff interlayers when said composite is subjected to impact.

15. The device of claim 14, wherein each sub-laminate layer comprises at least one unidirectional tape comprising parallel monofilaments embedded in a resin.

16. The device of claim 14 comprising multiple antiballistic composites nested into a plate system.

17. The device of claim 14 further comprising a ceramic or metallic component.

18. The device of claim 14, wherein said viscoelastic dilatory material comprises a rate-sensitive high-rate stiffening polymer or a polymer foam.

19. The device of claim 14, wherein said device is worn to provide anti-penetration, load spreading, impact management and shock management to the wearer.

20. The device of claim 19, wherein said device is a vest.