Patent Publication Number: US-2012024139-A1

Title: Ballistic -resistant laminate assemblies and panels

Description:
This application is a continuation-in-part application of U.S. patent application Ser. No. 10/421,627, entitled METHOD FOR FORMING OR SECURING UNIDIRECTIONALLY-ORIENTED FIBER STRANDS IN SHEET FORM, SUCH AS FOR USE IN A BALLISTIC-RESISTANT PANEL, which is a continuation of U.S. patent application Ser. No. 09/528,782, entitled METHOD FOR FORMING OR SECURING UNIDIRECTIONALLY ORIENTED FIBER STRANDS IN SHEET FORM, SUCH AS FOR USE IN A BALLISTIC-RESISTANT PANEL, filed Mar. 17, 2002, which is incorporated herein in its entirety by reference, and which claims priority to U.S. Provisional Patent Application No. 60/125,403, also incorporated herein in its entirety by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to forming or securing fiber strands in sheet form and, more particularly, to forming or securing fiber strands in sheet form for use in a ballistic-resistant laminate. 
     BACKGROUND OF THE INVENTION 
     Unidirectional fiber materials are used in ballistic-resistant structures and are disclosed, e.g., in U.S. Pat. Nos. 4,916,000, 4,079,161, 4,309,487, and 4,213,812. A non-woven ballistic-resistant laminate referred to by the trademark “Spectra-Shield” is manufactured by Allied-Signal, Inc. The laminate structure is used in soft body armor to protect the wearer against high-velocity bullets and fragments. “Spectra-shield” was made by first forming a non-woven unidirectional tape, which was composed of unidirectional polyethylene fibers and an elastic resin material that held the fibers together. The resin penetrated the fibers, effectively impregnating the entire structure with the resin product. Two layers, or arrays, of the unidirectional tape were then laminated together (cross-plied) at right angles to form a panel. The panel was then covered on both sides with a film of polyethylene. The film prevented adjacent panels from sticking together when the panels were layered in the soft body armor. The final panel was heavier and stiffer than desired for use as a ballistic-resistant panel. The weight and stiffness were due in part to the penetration of the entire structure with the resin product. 
     Non-woven ballistic-resistant laminates without resins are disclosed, e.g., in U.S. Pat. Nos. 5,437,905, 5,443,882, 5,443,883, and 5,547,536. A sheet of non-woven ballistic-resistant laminate structure was constructed of high performance fibers without using resins to hold the fibers together. Instead of resin, thermoplastic film was bonded to outer surfaces of two cross-plied layers of unidirectional fibers to hold the fibers in place. The film did not penetrate into the fibers. A sufficient amount of film resided between the bonded layers to adhere the layers together to form a sheet. Bonding the two layers of unidirectional fibers cross-plied to one another was necessary to meet structural requirements of the ballistic-resistant panel, such as impact force distribution. The individual sheets were placed loosely in a fabric envelope of an armored garment to form a ballistic-resistant panel. 
     SUMMARY 
     A ballistic-resistant laminate assembly is provided that overcomes drawbacks experienced in the prior art and achieves other benefits. One aspect of the invention provides a ballistic-resistant laminate assembly having a first layer with a plurality of ballistic-resistant fiber strands positioned adjacent to each other, a plurality of first bonding strips, and a plurality of second bonding strips. The first bonding strips are spaced apart from each other by a selected distance and are at a first orientation with the fiber strands. The second bonding strips are cross-plied relative to the first bonding strips to form a bi-directional array of bonding strips connected to the fiber strands. The second bonding strips are spaced apart from each other by a selected distance and are connected to the fiber strands at a predetermined angle relative to the fiber strands. In one embodiment, the first and second bonding fibers include ballistic-resistant fibers coated with an adhesive material. In one embodiment, the first and second bonding strips are bonding fibers configured in a woven arrangement with the fiber strands. A first laminate film is positioned on one side of the fiber strands and bonded to the first layer. A second laminate film is positioned adjacent to a side of the fiber strands opposite the first laminate film. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a ballistic-resistant fiber panel with ballistic-resistant fiber strands and bonding fibers connected to the fiber strands according to one embodiment of the invention. 
         FIG. 2A  is a plan view of a ballistic-resistant fiber panel with ballistic-resistant fiber strands and an array of bi-directional bonding fibers connected to the fibers in accordance with another embodiment of the invention. 
         FIG. 2B  is a plan view of a ballistic-resistant fiber panel in accordance with another embodiment of the invention. 
         FIG. 2C  is a plan view of a ballistic-resistant fiber panel in accordance with another embodiment of the invention. 
         FIG. 2D  is a plan view of a ballistic-resistant fiber panel in accordance with yet another embodiment of the invention. 
         FIG. 3  is a partial, exploded isometric view of one embodiment including thermoplastic sheets laminating the ballistic-resistant fiber panel of  FIG. 1 . 
         FIG. 4  is a partial, exploded isometric view of another embodiment of a laminated ballistic-resistant fiber panel without interwoven bonding fibers. 
         FIG. 5  is a partial, exploded isometric view of another embodiment of a laminated fiber panel including first and second sets of laminated ballistic-resistant fiber panels cross-plied relative to each together. 
         FIG. 6  is a partial, exploded isometric view of yet another embodiment of a laminated fiber panel with alternating layers of laminated ballistic-resistant fibers and laminate film. 
         FIG. 7  is a partial, exploded isometric view of another embodiment of layers of laminated ballistic-resistant fibers and laminate films. 
         FIG. 8  is a partial isometric view of several laminated ballistic-resistant fiber panels stitched together to form a packet under one embodiment of the invention. 
         FIG. 9  is a partial isometric view of another embodiment of several laminated ballistic-resistant fiber panels stitched together. 
         FIG. 10  is a partial, exploded isometric view of yet another embodiment of several stitched-together packets of laminated ballistic-resistant fiber panels. 
         FIG. 11  is an armored body garment under one embodiment of the invention. 
         FIG. 12  is a partial, exploded isometric view of another embodiment having a plurality of ballistic-resistant fiber panels joined together. 
     
    
    
     DETAILED DESCRIPTION 
     The inventors have found limitations and inefficiencies with respect to the performance and to the manufacturing of the prior art ballistic-resistant panels. The prior art laminated panels gave structure to the unidirectional fibers and served to prohibit adjacent sheets from sticking together, but they also facilitated movement between the sheets. Thus, the initial impact from, e.g., a bullet to a ballistic-resistant panel comprised of loose laminated sheets displaced and rotated the sheets within the pocket such that the anti-ballistic characteristics were compromised for subsequent bullets. Additionally, the impact from the bullet bunched and pulled the individual fiber strands in the sheets and further degraded the integrity of the ballistic panel. 
     When an armor vest is tested in accordance with nationally recognized standards, the vest is shot six times at a pre-established distance and in a specific shot pattern. The inventors found with the prior art that, when the bullet pulled the fibers toward entry, the bullet significantly weakened the areas that fibers were pulled from such that by the fourth and fifth shots, bullets penetrated a raised weakened strike area. Further, in the absence of resins or adhesives, the number of fibers per inch in a panel must be reduced to get opposing laminated sheets to fuse together. Increasing the density of the fibers to improve ballistic performance resulted in a panel that delaminated. To form the prior art sheets, fiber spools were unwound as thermoplastic sheets simultaneously laminated the fibers to provide alternating layers of fibers and thermoplastic sheets. It was not always feasible, economical, or ballistically prudent to simultaneously bond the thermoplastic film on one side of the unspooling fibers. Without the thermoplastic film, however, the unspooled fibers lacked structure and collapsed. 
     Under one aspect of the invention, a ballistic-resistant fiber panel includes a plurality of ballistic-resistant fiber strands and bonding strips, such as a plurality of bonding fibers connected to the fiber strands. Under another aspect of the invention, two thermoplastic sheets laminate the fiber panel between them. Under another aspect, one set of bonding strips is connected to the fiber strands at one predetermined angle, and a second set of bonding strips at another angle relative to fiber strands is cross-plied with the first bonding strips to form an array of bi-directional bonding strips connected to the ballistic-resistant fiber strands. Under yet another aspect of the invention, several of the laminated ballistic-resistant fiber panels are stitched or otherwise bound together to form packets. Methods for forming or securing ballistic-resistant fiber strands in sheet form are described in detail below. In the following description, numerous specific details are provided, such as specific uses, fiber orientations, numbers of layers, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will readily recognize that the invention can be practiced without one or more of the specific details. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     As illustrated in  FIG. 1 , a flexible ballistic-resistant fiber panel  110  includes the bonding strips formed by bonding fibers  130  interwoven with strands of ballistic-resistant fibers  120 . As the ballistic-resistant fibers  120  are unspooled, they may be passed through a comb guide where the ballistic-resistant fibers are further paralleled and spaced into a predetermined uniform density. In one embodiment, the ballistic-resistant fibers  120  are aramid fibers, with a 1000 denier fiber construction and approximately 17 ends/inch untwisted tows sheet construction. In another embodiment, the ballistic-resistant fibers  120  are aramid fibers, with a 840 denier fiber construction and approximately 20 ends/inch unidirectional untwisted tows sheet construction. In other embodiments, the ballistic-resistant fibers  120  can be high performance fibers having a tensile strength of at least 9 grams/denier. 
     As the ballistic-resistant fibers  120  are unspooled to form a fiber panel  110 , the bonding fibers  130  are interwoven at an angle with respect to the ballistic-resistant fibers  120 . In the illustrative embodiment, the bonding fibers  130  are interwoven perpendicular to the ballistic-resistant fibers  120  on approximately one-inch centers. Preferably the bonding fibers  130  are spaced one-half inch to two inches, and more preferably, the bonding fibers  130  are evenly spaced one inch apart. The bonding fibers  130  are positioned to alternatively go under and over adjacent sets of the ballistic-resistant fibers  120  in a woven arrangement, thereby providing a bi-directional, or multidirectional arrangement of fibers. In selected embodiments, the sets of ballistic-resistant fibers  120  that the bonding fibers go over or under have a width of about one-half inch to two inches, so as to substantially correspond to the distance between adjacent bonding fibers  130 . 
     In one embodiment, the bonding fibers  130  are an ethylene vinyl acetate with a polyester core. The coating may be made of natural or manmade polymers, copolymers, waxes, or mixtures thereof. The coating is configured to at least partially coat and securely adhere to the ballistic-resistant fibers  120 , thereby substantially holding the ballistic-resistant fibers together. Representative examples include, but do not limit the scope of use to, the following: styrene, butadiene, poly-butadiene, polyvinylchloride, polyethylene, polypropylene, polyvinyl acetate (plasticized), acrylics, polyvinyl pyrrolidene compounds, natural latex, paraffin wax of the hot melt type, casein, carboxy cellulose esters, and ethers. The core may alternatively be constructed out of nylon, cotton, or aramid fiber or other high performance fibers having a tensile strength of at least 9 grams/denier. In other embodiments, the bonding fibers  130  are constructed of a ballistic-resistant fiber, such as an aramid fiber, with a coating of heat- or pressure-sensitive adhesive that will adhere to the ballistic-resistant fibers  120 . The bonding fibers  130  can be substantially the same as the ballistic-resistant fibers  120 . Alternately, the bonding fibers  130  can be a different size than the ballistic-resistant fiber  120 . 
     After the bonding fibers  130  are interwoven with the ballistic-resistant fibers  120 , they are bonded into a ballistic-resistant oriented fiber panel  110 , for example, with heat and pressure from either static heat or an autoclave. The desired temperature range during heating is preferably up to 500 degree F., more preferably in the range of 225-375 degree F., and most preferably 265 degree F. under 45 psi of pressure. In addition to heat bonding the bonding fibers  130  to the ballistic-resistant fibers  120 , bonding can be effected by other methods depending upon the particular chemical composition of the fiber&#39;s coating. For example, bonding can be done by moisture, the use of organic solvents, high-pressure alone, or contact pressure. Such bonding techniques, however, should not adversely affect the ballistic-resistant fibers  120  or destroy the configuration of the fibers that the bonding fibers  130  are to reinforce. Further, the coating of the bonding fibers  130  must bond with whatever surface coating or laminate is to be applied to the ballistic-resistant fiber panel  110 . 
     Interweaving the bonding fibers  130  with the ballistic-resistant fibers  120  allows the fiber panel  110  to be handled, transported, and processed either at a different location or at a later time. This feature provides advantages, including both efficiency and economy. Under traditional manufacturing methods, it was necessary to secure the thermoplastic film onto one side of the fibers at the same time the ballistic-resistant fibers were unspooled to provide structure for the ballistic-resistant fibers and to preserve the sheet configuration of the fibers. The bonding fibers  130  provide this structure to the ballistic-resistant fibers  120 . Thus, a thermoplastic film may be laminated to the ballistic-resistant fibers  120  either at the same time as the ballistic-resistant fibers  120  are unspooled or at a later time. 
       FIG. 2A  is a plan view of a ballistic-resistant fiber panel  200 , with a woven array of bi-directional bonding fibers  130  connected to the ballistic-resistant fibers  120  in accordance with another embodiment of the invention. In the illustrated embodiment, the bonding fibers  130  include a first set of spaced-apart bonding fibers  228  generally perpendicular to the ballistic-resistant fibers  120 , although the bonding fibers can be oriented at another selected angle relative to the ballistic-resistant fibers. The fiber panel  200  also has a second set of spaced-apart bonding fibers  230  substantially parallel with the ballistic-resistant fibers  120 . The first set of bonding fibers  230  is cross-plied and arranged in a woven configuration with the second set of bonding fibers  228  and with the ballistic-resistant fibers  120 . The cross-plied bonding fibers  228  and  230  form a bi-directional array  210  of bonding fibers that hold the ballistic-resistant fibers  120  in a parallel orientation. The fiber panel  200  can then be handled and manipulated in the manufacturing processes to form ballistic-resistant panels or the like. In one embodiment, the first and second sets of bonding fibers  228  and  230  are aramid fibers coated with selected adhesive, such as a heat and/or pressure sensitive adhesive. 
     In another embodiment shown in  FIG. 2B , the ballistic-resistant fiber panel  200  has an array of bi-directional bonding strips  1130  connected to the ballistic-resistant fibers  120 . In the illustrated embodiment, the bonding strips  1130  include a first set of spaced-apart bonding strips  1228  generally perpendicular to the ballistic-resistant fibers  120 , although the bonding strips can be oriented at another selected angle relative to the ballistic-resistant fibers. The fiber panel  200  also has a second set of spaced-apart bonding strips  1230  substantially parallel with the ballistic-resistant fibers  120 . The first set of bonding strips  1230  is cross-plied with the second set of bonding strips  1228  and with the ballistic-resistant fibers  120 . In one embodiment, the first and second sets of bonding strips  1228  and  1230  are lengths of heat and/or pressure sensitive adhesive applied to the ballistic resistant fibers  120 . 
     The bonding strips  1228  and  1230  of one embodiment can be applied the ballistic-resistant fibers  120  while the ballistic resistant fibers are being unspooled and arranged in the parallel configuration, or the bonding strips can be applied after the ballistic-resistant fibers have been arranged in the parallel configuration. The cross-plied bonding strips  1228  and  1230  form a bi-directional array  1210  of bonding strips that hold the ballistic-resistant fibers  120  in a parallel orientation. The fiber panel  200  can then be handled and manipulated in the manufacturing processes to form ballistic-resistant panels or the like. The bonding strips  1228  and  1230  of different embodiments can be fibrous or non-fibrous. The bonding strips  1228  and  1230  in selected embodiments can be applied in a liquid or semi-liquid format to form spaced-apart stripes of bonding material that act, inter alia, to hold the ballistic-resistant fibers  120  together. In other embodiments the bonding strips  1228  and  1230  can be elongated lengths of material, such as a tape-like material, applied to the ballistic resistant fibers  120  during or after the ballistic-resistant fibers are arranged in the parallel configuration. 
     In another embodiment shown in  FIG. 2C , the ballistic-resistant fiber panel  200  has the first set of spaced-apart bonding fibers  228  oriented at an angle relative to the ballistic-resistant fibers  120 . The bonding fibers  228  in the illustrated embodiment are made of ballistic-resistant fibers, such as aramid fibers, coated with a selected heat and/or pressure sensitive adhesive. In one embodiment, the angle of the first set of bonding fibers  228  is generally between 0 degrees and 90 degrees. In another embodiment, the angle is generally between approximately 30 degrees and 60 degrees, inclusive. The first set of bonding fibers  228  can be woven with the ballistic-resistant fibers  120 . The second set of spaced-apart bonding fibers  230  are oriented at second angle relative to the ballistic-resistant fibers  120  and are oriented at an angle relative to the first set of bonding fibers  228 . Accordingly, the first and second sets of bonding fibers  228  and  230  provide a multi-axial array of bonding fibers. 
     The bonding fibers  230  in the second set are also made of ballistic-resistant fibers, such as aramid fibers, coated with a selected heat and/or pressure sensitive adhesive. The bonding fibers  230  in this embodiment are not perpendicular or parallel to the ballistic-resistant fibers  120 . In one embodiment, the angle of the second set of bonding fibers  230  relative to the ballistic-resistant fibers  120  is between 90 degrees and 180 degrees. In another embodiment, the angle is between approximately 120 degrees and 150 degrees, inclusive. In one embodiment, the second set of bonding fibers  230  are woven with the ballistic-resistant fibers  120  and with the first set of bonding fibers  228 . The first and second sets of bonding fibers  228  and  230  can be perpendicularly oriented relative to each other, or they can be oriented at other angles to provide the bi-directional woven array of bonding fibers. Accordingly, the ballistic-resistant fibers and the first and second sets of bonding fibers  228  and  230  in the illustrated embodiment form a triaxial array of ballistic resistant fibers that form the ballistic-resistant fiber panel. 
     In another embodiment, a ballistic-resistant panel is formed with the bonding fibers  120  and three or more sets of spaced apart bonding fibers made of ballistic-resistant fibers coated with a selected heat and/or pressure-sensitive adhesive. Each set of these spaced apart bonding fibers are angularly offset relative to each other and relative to the ballistic-resistant fibers  120 . Accordingly, the ballistic-resistant panel is formed with a multi-axial array of ballistic-resistant bonding fibers. 
     In one embodiment, the ballistic-resistant bonding fibers  228  and  230  can be made of the same material as the ballistic-resistant fibers  120  and coated with a selected adhesive coating. Alternatively, the bonding fibers  228  and  230  can be made of an adhesive-coated ballistic-resistant material having performance characteristics different than the ballistic-resistant fibers  120 . As an example, the ballistic-resistant bonding fibers  228  and  230  can be coated aramid fibers with a smaller denier fiber construction and smaller diameter than the denier fiber construction and diameter of the ballistic-resistant fibers  120 . 
     In yet another embodiment shown in  FIG. 2D , the ballistic-resistant fiber panel  200  has a first set of spaced-apart bonding strips  1228  oriented at an angle relative to the ballistic-resistant fibers  120 . The bonding strips  1228  in the illustrated embodiment contain a selected heat and/or pressure sensitive adhesive. In one embodiment, the angle of the first set of bonding strips  1228  is generally between 0 degrees and 90 degrees. In another embodiment, the angle is generally between approximately 30 degrees and 60 degrees, inclusive. The first set of bonding strips  1228  can be applied during or after the ballistic-resistant fibers  120  are arranged in the parallel configuration. The second set of spaced-apart bonding strips  1230  are oriented at second angle relative to the ballistic-resistant fibers  120  and are oriented at an angle relative to the first set of bonding strips  1228 . Accordingly, the first and second sets of bonding strips  1228  and  1230  provide a multi-axial array of bonding strips. 
     As illustrated in  FIG. 3 , lower and upper thermoplastic films  340  and  342 , respectively, are provided on bottom and top sides of the single fiber panel  110 , and then secured or laminated thereto so that the ballistic-resistant fibers are securely sandwiched between the films to form a flexible, ballistic-resistant sheet  300 . In one embodiment, the thermoplastic films  340  and  342  are extremely thin, typically less than 0.35 mils, to maintain the flexibility of the laminated ballistic-resistant sheet  300 . Alternatively, thicker laminate films up to approximately 0.5 mils may be used to form a laminated fiber sheet of greater rigidity. 
     In one embodiment, the laminate film will coat the exterior surfaces of the ballistic-resistant fibers  120  to encapsulate them, but will not impregnate the fibers. Sufficient plasticized film material flows between adjacent ballistic-resistant fibers  120  to bond the thermoplastics films  340  and  342  to the ballistic-resistant fibers. The thermoplastic films  340  and  342  may be a polyethylene film. Due to the structure provided by bonding fibers  130  and  230  (shown in phantom lines in  FIG. 3 ), the thermoplastic films  340  and  342  may be laminated over the ballistic-resistant fibers  120  either as the ballistic-resistant fibers are unspooled and interwoven with the bonding fibers  130  or at a later time. The thermoplastic films  240  and  242  laminate to each side of the ballistic-resistant fibers  120  to form the flexible, laminated, ballistic-resistant fiber sheet  300 . The flexible sheet  300  may be used individually or may be combined with other sheets as described below, to form a variety of items, including ballistic-resistant panels. 
     The bonding fibers  130  further provide structure to which the thermoplastic films  340  and  342  can bond. Because the thermoplastic films  340  and  342  bond with the interwoven bonding fibers  130 , the fiber panel  110  may contain a greater density of ballistic-resistant fibers  120 . The bonding fibers  130  of these embodiments thus provide at least two functions: the bonding fibers help prevent the ballistic-resistant fiber panel from spreading or delaminating before and after the thermoplastic films  340  and  342  are laminated over the ballistic-resistant fibers  120 , and the bonding fibers provide the panel enhanced buoyant characteristics. The greater density of the ballistic-resistant fibers  120  in the panel combine with the bonding fibers  130  to form interstitial air pockets  344  trapped between the laminate films  340  and  342 . 
     The bonding fibers  130  allow the density of the ballistic-resistant fibers  120  to be maximized by giving the fiber panel  110  further structure while preventing delamination of the laminated fiber sheet  300  by bonding with the thermoplastic film. The bond between the thermoplastic sheets  340  and  342  and the bonding fibers  130  create equally spaced sealed interstitial air pockets that, when used in a ballistic panel, produce buoyant ballistic panels. In the embodiments shown in  FIGS. 2A and 2B  having the bi-directional woven array  210  of bonding fibers, both sets of the bonding fibers  228  and  230  act with the thermoplastic films  340  and  342  shown in  FIG. 3  to form the interstitial air pockets  344  that provide the ballistic-resistant sheet  300  with a positive buoyancy. Accordingly, a plurality of ballistic-resistant sheets  300  can be joined together (as discussed in greater detail below) to form a flexible, ballistic-resistant panel having positive buoyancy. The buoyant flexible, ballistic-resistant panel can be used to make a selected assembly, such as a ballistic-resistant garment or the like. 
     The fiber panels  110 ,  200 , and  300  discussed above are substantially flexible ballistic-resistant panels. In other embodiments, sufficient heat or heat with sufficient pressure can be applied to the thermoplastic films  340  and  342  for a sufficient duration to melt one or both of the thermoplastic films  340  and  342  into the ballistic-resistant fiber  120  to form a semi-rigid or rigid structure. Before heating the thermoplastic films  340  and  342 , the laminated ballistic-resistant fiber sheet  300  may be configured into any variety of shapes. This semi-rigid or rigid structure may be used alone or may be used in combination with other panels to form any variety of items, including, but not limited to, cargo boxes, storage boxes, aircraft containers, water skis, snow skis, hockey sticks, vehicle bodies such as boat hulls, and protective elements such as helmets for racing, military use, or bicycling. 
     As illustrated in  FIG. 4 , another embodiment includes a fiber panel  410  of ballistic-resistant fibers  120  with lower and upper sheets of thermoplastic films  340  and  342  provided on a bottom and top surface of the fiber panel to form a flexible laminated ballistic-resistant fiber sheet  400 . The ballistic-resistant fiber panel  410  laminated on both sides by thermoplastic films  340  and  342  provides a fiber sheet  400  with maximum flexibility while providing sufficient structure to prevent degradation of the fiber sheet&#39;s configuration. This ballistic-resistant fiber panel  410  may be used individually or in combination with other fiber panels disclosed herein. Alternatively, the thermoplastic films  340  and  342  may be heated such that the thermoplastic films will melt and encapsulate or impregnate the individual fiber strands  120  resulting in a substantially rigid sheet (not shown). 
     The decision to produce either a rigid or a flexible fiber sheet is typically dictated by the end use of the fiber sheet  400 . Multiple pliable panels or sheets  110 ,  200 ,  300 , or  400  can be used to form flexible ballistic-resistant panels used in a wearable garment, while providing ballistic protection to the wearer. Several sheets  110 ,  200 ,  300 , or  400  in a rigid configuration can be used for other ballistic-related structures, such as helmets configured to fit the wearer&#39;s head. 
     As illustrated in  FIG. 5 , another embodiment provides a ballistic-resistant, laminated panel  500  that has a first laminated fiber sheet  510  with ballistic-resistant fibers  120  oriented in a first direction (as illustrated in  FIG. 1 ), and a second laminated ballistic-resistant fiber sheet  512  having ballistic-resistant fibers  120  oriented in a second direction. As illustrated, the sheets  510  and  512  each include bonding fibers  130  positioned substantially perpendicular to the ballistic-resistant fibers  120  and interwoven with the ballistic-resistant fibers  120 . In the embodiments providing the array  210  of bi-directional bonding fibers  130  and  230 , the cross-plied bonding fibers are substantially perpendicular to each other. Accordingly, one set of bonding fibers  230  is substantially parallel to the fiber strands  120 , and the other set of bonding fibers  130  is substantially perpendicular to the fiber strands. In one embodiment, the bonding fibers  230  can be ballistic-resistant fibers angularly offset relative to the fiber strands  120 , as discussed above with reference to  FIG. 28 . 
     In one embodiment, the bonding fibers  130  are visual indicators that allow for easy confirmation that adjacent fiber panels  110  are cross-plied relative to each other. As an example, the bonding fibers  130  parallel to the ballistic-resistant fibers  120  in each laminated sheet  512  are colored differently than the ballistic-resistant fibers. Accordingly, when the two laminated sheets  510  and  512  are adjacent to each other, a person can quickly and easily determine whether the ballistic-resistant fibers  120  are cross-plied by looking at the relative orientation of the colored bonding fibers. If the colored bonding fibers  130  of each adjacent laminated sheet  510 / 512  are cross-plied relative to each other, the person knows that the ballistic-resistant fibers are properly cross-plied. In one embodiment adjacent fiber panels  110  can have different colored bonding fibers  130 , and in alternate embodiments the bonding fibers in each fiber panel can have the same color although different from the ballistic-resistant fibers  120 . In the embodiment having the bi-directional array  210  of bonding fibers  130 , the bonding fibers can be configured so that some or all of the bonding fibers  230  parallel to the ballistic-resistant fibers  120  have a different color than the cross-plied bonding fibers  228  in that fiber panel  110 . 
     The laminated panel assembly  500  of the illustrated embodiment has multiple cross-plied fiber panels  110 , and each fiber panel  110  is laminated between lower and upper laminate films  340  and  342 , thereby forming laminated sheets  510  and  512  with a configuration of film/fiber panel/film. Multiple laminated sheets  510 ,  512  can be joined together such that the ballistic-resistant fibers  120  of adjacent layers are cross-plied relative to each other. The resulting laminated sheet  500  has a lamination configuration of film/fiber panel/film/film/fiber panel/film. . . . The multiple laminated layers  510 ,  512  can be retained together by an adhesive provided between layers, or by stitching the layers together or by other laminating techniques. As discussed above, the bonding fibers  130  provide structure to the ballistic-resistant fibers  120  and allow the panel  110  to be manufactured without the thermoplastic film  340  or  342 . Alternatively, if the thermoplastic film  340  or  342  is bonded to either a first or a second surface when the ballistic-resistant fibers  120  are unspooled and combined with the bonding fibers  130  in the weave pattern to form the ballistic-resistant panel  110 , then the thermoplastic film may be used to provide additional structure to the panel. 
     When the ballistic-resistant fibers  120  are combined with the bonding fibers  130  in the weave pattern, layered on or between thermoplastic films  340  and  342 , and laminated to produce a flexible sheet  500 , the resulting flexible sheet is easy to handle without damaging, loosening, or substantially degrading the effectiveness of the ballistic-resistant fibers. The flexible, laminated sheet  500  is also quite buoyant because of the interstitial air pockets  344  trapped within the sheet between the laminate films  340  and  342 . 
       FIG. 6  is a partial exploded isometric view of an alternate embodiment of a laminated fiber panel sheet  600 . The laminated sheet  600  includes a first fiber panel  110  with the ballistic-resistant fibers  120  aligned in one direction. A second fiber panel  110  is cross-plied with the first fiber panel so that the ballistic-resistant fibers  120  of the second panel are substantially perpendicular to the ballistic-resistant fibers of the first panel. Accordingly, the laminated sheet  600  provides the cross-plied layers of the ballistic-resistant fibers  120 . In other embodiments, the fiber panels  110  can be oriented with the ballistic-resistant fibers  120  at selected angles relative to each other, and not necessarily limited to a perpendicular orientation. In other embodiments, additional fiber panels  110  can be provided in the laminated sheet  600 , and each fiber panel  110  can be selectively oriented in a cross-plied configuration relative to the adjacent layers as desired. 
     In the laminated sheet  600  as illustrated in  FIG. 6 , the first fiber panel  602  is bonded or otherwise adhered to a lower laminate film  606  such that the lower laminate film is attached to the bottom surface of the first fiber panel. A middle laminate film  608  is attached to the top surface of the first fiber panel  602 , so that the first fiber panel is sandwiched between the lower and middle laminate films  606  and  608 . The second fiber panel  604  is adhered along its bottom surface to the middle laminate film  608  so the middle laminate film is sandwiched between the first and second fiber panels  602  and  604 . An upper laminate film  610  is adhered to the top surface of the second fiber panel  604 . Accordingly, the structure of the laminated sheet  600  provides alternating layers of film and fiber panel to provide a configuration of film/fiber panel/film/fiber panel/film/ . . . with each successive fiber panel  110  being cross-plied relative to its adjacent fiber panels. Each of the fiber panels  602 / 604  can have the bonding fibers  130  or the array  210  of the bi-directional bonding fibers. 
       FIG. 7  is a partial exploded isometric view of another embodiment of a laminated sheet  700 . The laminated sheet  700  includes a first ballistic-resistant fiber panel  702  directly attached to a second ballistic-resistant fiber panel  704  that has the ballistic-resistant fibers  120  cross-plied relative to the ballistic-resistant fibers of the first fiber panel. The bonding fibers  130 / 230  provide adhesive characteristics that at least partially bond the first and second fiber panels  702  and  704  together. The first and second laminated panels  702  and  704  can be provided with one set of spaced-apart bonding fibers  130  at a selected angle relative to the ballistic-resistant fibers  120  (e.g., perpendicular). In other embodiments, fiber panels  702  can include the array  210  of bonding fibers  130 , as discussed above. 
     The laminated sheet  700  illustrated in  FIG. 7  has a bottom laminate film  340  attached to the bottom surface of the first fiber panel  702 , such that first fiber panel is between the laminate film and the second fiber panel  704 . The laminated sheet  700  also has a top laminate film  342  attached to the top surface of the second fiber panel  704 , such that the second fiber panel is between the top laminate film and the first fiber panel  702 . Accordingly, the laminated sheet  700  has a lamination configuration of film\fiber panel\fiber panel\film. The laminated sheet  700  illustrated in  FIG. 7  shows the use of only two laminated panels  702  and  704 , although alternate embodiments can provide additional layers of fiber panels between the laminate films  340  and  342 . The laminated sheet  700  can be a flexible sheet, but in other embodiments, the laminated sheet can be a semi-rigid or rigid structure. 
       FIG. 8  is an isometric view of a stack of layers  800  of laminated sheets stacked on top of one another with the ballistic-resistant fibers  120  of each fiber panel  110  selectively oriented relative to the ballistic-resistant fibers of adjacent fiber panels, such as parallel, perpendicular, or at other angles. The stack of layers  800  can be made up of multiple layers of any one of the laminated fiber sheets  300 ,  400 ,  500 ,  600 , and/or  700  discussed above, or any mixed combination of the laminated fiber sheets. The stack of layers  800  is secured together by stitches  810  to form a packet  820 . 
     In another embodiment, adjacent sheets  300 / 400 / 500 / 600 / 700  can be secured together with an adhesive provided between the adjacent layers. The adhesive can be applied in selected patterns on the facing surfaces, so as to control the stiffness or rigidity of the resulting stack of layers  800 . The stack of layers  800  adhered together can also be stitched together at selected locations or patterns as needed for the particular application for which the packet  820  is to be used. Further, any one of the sheets illustrated in  FIGS. 1-7  may be used in any combination to form the packet  820 . Specifically, when using the ballistic-resistant laminated sheets  500  illustrated in  FIG. 5  to form the packet  820 , preferably three to eight sheets are sewn together to form the packet  820 , more preferably four to six panels, and most preferably five panels are used to form the packet. When using the ballistic-resistant fiber sheets  300  or  400  ( FIG. 3  or  4 ) to form the packet  820  for use in a ballistic-resistant panel assembly, the sheets are placed such that the orientation of ballistic-resistant fibers is rotated a selected angle with respect to adjacent sheets. 
     Stitching the layers  800  together to form the packet  820  provides improved resistance to ballistic penetration in a ballistic panel with fewer total fiber panels required, as described below. In one embodiment, preferably four to ten packets of laminated sheets  500  are used to form a ballistic panel, more preferably four to eight packets and most preferably six packets are used to form a ballistic-resistant packet  820 . When a bullet hits a ballistic-resistant panel  820 , the bullet penetrates the initial layers  500  and the impact force of the bullet displaces secondary layers. When the ballistic-resistant panel  820  is made up of several individual ballistic-resistant fiber sheets or panels, the force of the bullet causes some fibers in the panel to push apart and separate and other fibers at the tip of the bullet to bunch. Adjacent fibers that the bullet does not actually penetrate are pulled out of position and weakened by the impact force of the bullet. This creates a path of reduced resistance through the panel. The result is that the integrity of the ballistic-resistant panel is significantly impaired after the first impact. Packets of ballistic-resistant fiber layers retain the benefit that the movement between the individual layers allows, i.e., shifting the bullet off course and diffusing the straight-line penetration of the bullet, while decreasing the penetration and the bunching caused by the bullet. The packets act like individual panels within the ballistic-resistant panel in that each individual packet acts independently of the adjacent packet. Thus the bullet&#39;s trajectory angles at each packet so that it does not create a path through the panel. 
     Fewer layers are used to form a ballistic-resistant panel of equivalent characteristics compared to prior systems; therefore, the resultant panel is more flexible and lighter in weight. When a bullet impacts a ballistic-resistant panel, the panel is subject to both the impact force of the bullet and a reverberating energy wave sent out ahead of the bullet. The components of the packet of this embodiment combine to provide a more efficient ballistic-resistant panel. Components include any one of or a combination of the following: density of the ballistic-resistant fibers in the panel, bonding thread, the cross-plied positioning of the fiber panels, thermoplastic films, the laminated fiber panels, and laminated panel assemblies stitched together in packets. The interaction between the individual packets works in a cooperative effort to provide an improved ballistic-resistant panel. Among other things, sewing the layers in a packet maximizes the anti-ballistic properties of the individual layers such that the resultant packet is stronger than the sum of the individual layers. Additionally, because fewer layers are required, the ballistic-resistant panel is less expensive to manufacture. 
     Stitching the layers  800  to form the packet  820  may be done by any variety of stitching patterns and is illustrated in  FIG. 8  as a diamond pattern. An alternative pattern includes vertical stitching perpendicular to the ballistic-resistant fibers. Vertical stitching helps prevent the fibers from pulling side to side. Vertical stitches are preferably evenly spaced, more preferably evenly spaced 2″-4″ apart and most preferably evenly spaced 3″ apart. Stitching patterns may also include perimeter stitching, continuous and noncontinuous patterns, and any other variety of stitching patterns. In addition to stitching to secure the sheets together to form a packet, any one of a number of devices, including, but not limited to, the following may be used: staples (permanent plastic or metal); dry or wet adhesive applied directly or on strips such as double-sided tape; various patterns of bar tacks; interlocking tabs in the sheets themselves or slots in the laminate; heat-fusible thread on the exterior of select sheets; stacking two or more thermoplastic films and applying heat while pressing them together and taking advantage of the “sticky” properties of the film element of the laminate; fine Velcro or similar hook and loop material between the layers of sheets, snaps, any permutations and/or combinations of all the above devices; induced static electrical charge; and interwoven magnetic material. Additionally, a wide variety of materials may be used for the stitching thread, including natural and manmade fiber threads, polymer-based threads (such as fishing line), fine steel or other metal or composite or alloy wire, and racket sports string (including natural, such as catgut, and synthetic materials). 
       FIG. 9  illustrates another embodiment of a packet  900  of several ballistic-resistant fiber sheets affixed together. As discussed above, any combination of sheets may be used to form the packet  900 , including, but not limited to, this illustrated combination layering of different sheets  500 ,  400 ,  300 ,  400  and  500 . As the individual sheet configurations have specific features or strengths, the positioning of the sheets within the packet will serve to highlight those features or strengths. 
     As illustrated in  FIG. 10 , the packets  820  or  900  are combined to form a ballistic-resistant panel  1000 . As is further illustrated in  FIG. 11 , one or more packets  820  or  900  can be bundled together and inserted in pockets  1100  to form a ballistic-resistant panel  1000 . This ballistic-resistant panel  1000  may be used as illustrated in a structure such as a vest  1150 . The packets  820  or  900  increase ballistic-resistant efficiency by helping to hold the sheets in position. Traditionally, the first impact or shot to the ballistic-resistant panel  1000  caused displacement and rotation of the sheets, which resulted in a less efficient ballistic-resistant panel for second or subsequent sheets. The stitching  810  or otherwise securing the individual sheets to form packets  820  or  900 , and then bundling the packets  820  or  900  together to form a ballistic-resistant panel  1000 , reduces the shifting and rotation caused by the initial shot. 
       FIG. 12  is a partially exploded isometric view of a ballistic-resistant panel  1200  in accordance with another embodiment. The ballistic-resistant panel  1200  is formed by a plurality of ballistic-resistant fiber sheets  1202 . Laminate films are not provided between the ballistic-resistant sheets  1202  in this embodiment. The sheets  1202  have the plurality of ballistic-resistant fibers  120  a set of spaced-apart bonding fibers  130  woven or bonding strips at a selected angle relative to the ballistic-resistant fibers. The bonding fibers  130  are shown in  FIG. 12  at one angle although other angular orientations, including a perpendicular orientation, could be used. The bonding fibers  130  can be ballistic-resistant fibers, such as aramid fibers, coated with a selected heat and/or pressure sensitive adhesive. In one embodiment, each ballistic-resistant sheet  1202  also has a second set of spaced-apart bonding fibers  130  or bonding strips woven with the first set of bonding fibers and with the ballistic-resistant fibers  120 . Accordingly, each ballistic-resistant fiber sheet  1202  is a multi-directional array of fibers. 
     The ballistic-resistant sheets  1202  are oriented so the ballistic-resistant fibers  120  of each sheet is cross-plied at a selected angle relative to the ballistic-resistant fibers of the adjacent sheets. The ballistic-resistant fibers  120  of adjacent sheets can be cross-plied approximately a 90 degree orientation, although angular orientations can be used. When the ballistic-resistant sheets  1202  are positioned together to form the panel  1200 , the bonding fibers  130  in each sheet bond to the ballistic-resistant fibers  120  of the sheet and also to the ballistic-resistant fibers and/or the bonding fibers of the adjacent sheets. The bonding fibers  130  securely retain the adjacent ballistic-resistant sheets  1202  together while maintaining the desired degree of flexibility or rigidity of the ballistic-resistant panel  1200 . The plurality of ballistic-resistant sheets  1202  in alternate embodiments can also be stitched together, as discussed above. 
     The impact of the bullet indents the ballistic-resistant panel and causes some of the fibers in the ballistic-resistant panel to compact at the front of the bullet while stretching and pulling other fibers out of position as the bullet moves through the ballistic-resistant panel. Additionally, the indentation from the force of the bullet in the ballistic-resistant panel in one location causes a resulting protrusion of the panel&#39;s flat surface surrounding the indentation. This protrusion can buckle the surface of the entire panel depending on the entry location of the bullet. This buckling creates an air pocket between the panel and the wearer&#39;s chest, which in turn impacts the integrity of the entire ballistic-resistant panel. 
     The various embodiments described above can be combined to provide further embodiments. All of the above U.S. patents and applications are incorporated by reference. Aspects of the invention can be modified, if necessary, to employ the systems, circuits, and concepts of the various patents and applications described above to provide yet further embodiments of the invention. 
     These and other changes can be made to the invention in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims, but should be construed to include all ballistic-resistant fiber sheets that operate under the claims. Accordingly, the invention is not limited by the disclosure, but instead its scope is to be determined entirely by the following claims.