CA2693638C

CA2693638C - Use of machine direction oriented films in ballistic articles

Info

Publication number: CA2693638C
Application number: CA2693638A
Authority: CA
Inventors: Chinkalben Patel
Original assignee: Barrday Inc
Current assignee: Barrday Inc
Priority date: 2010-02-19
Filing date: 2010-02-19
Publication date: 2018-11-20
Anticipated expiration: 2030-02-19
Also published as: CA2693638A1

Abstract

Described are protective and/or ballistic resistant articles made from one or more layers of fabric bound to one or more layers of a machine direction oriented film. The described articles exhibit excellent abrasion resistance. The articles include those made using woven and/or non-woven fabrics such as unidirectional fabrics. Also described are protective and/or ballistic resistant articles wherein the matrix comprises greater than 15% by weight of the total composite. Methods for producing ballistic- resistant articles using woven and/or non-woven fabrics and machine direction oriented film are provided.

Description

Title: USE OF MACHINE DIRECTION ORIENTED FILMS IN BALLISTIC ARTICLES
FIELD
[0001] This application relates to the field of protective and ballistic-resistant articles, and more particularly to fabric composites suitable for use in protective and ballistic-resistant articles.

BACKGROUND

[0002] High performance protective composites suitable for use in stab, impact, blast and/or ballistic-resistant articles are known in the art. Such materials often include layers of woven or non-woven fabrics made from high-performance fibers or yarns.
Commonly used non-woven fabrics include unidirectional (UD) fabrics with layers of fibers aligned to be substantially parallel to one another along a common fiber direction.

[0003] Typically, matrix resins, films or combination of both are used in ballistic-resistant or high performance fabric articles to hold fibers in a desired orientation, to promote adhesion between adjacent fabric layers or to serve as an exterior surface protective layer. Commonly used films or laminates include those made by extrusion blowing elastomeric materials such as styrenic block copolymers, polyolefins, polyurethanes, polyesters, polyether esters, or polyamides. Commonly used resins include elastomeric or hard polymeric resins such as those made from styrenic block copolymers, polyacrylates, polyurethanes or polyisoprenes etc.

[0004] In soft armor ballistic-resistant articles abrasion resistance is a critical quality. Soft armor articles are typically comprised of multiple layers of composite materials such as unidirectional (UD) fabrics. As a result, adjacent layers within the ballistic article abrade against each other during normal handling and wear.
To ensure performance and product integrity are not comprised due to abrasion during routine operations and regular wear, fabrics suitable for use in ballistic articles are tested to specific abrasion resistance thresholds such as ASTM D3886-99 (Stoll Abrasion).

[0005] Many UD products have limited abrasion resistance when tested against UD or woven fabrics. Particularly in soft armor applications, outer surfaces of UD are laminated with thermoplastic films. Films are typically lightly adhered to the UD sheets to minimize impregnation of the fibers by the film or adhesive. As a result, during abrasion testing polymer films come off with relative ease and fiber construction easily weakens.

[0006] Abrasion resistance is also a desirable quality in hard ballistic articles that are relatively inflexible compared to soft ballistic articles. External layers of abrasion resistant material in hard ballistic articles can help prevent structural failures of the underlying composite materials in response to an abrasive environment.

[0007] While matrix resins and films are useful for maintaining the structural integrity of a composite material and for holding the fibers in place (such as in UD
fabrics), their contribution within a ballistic article towards absorbing and dissipating impact energy is relatively insignificant; the primary resistance forces within a ballistic article are provided by the high-performance fabric or fiber network.
Accordingly, advances in the protective and ballistic-resistance articles have strongly focused on creating systems with minimal resin or matrix systems.

[0008] Van de Goot (US 6,238,768) describe an antiballistic shaped part composed of a stack of composite layers, wherein each layer contains at most 10% of an elastomeric matrix material.

[0009] Bhatnagar et al. (US 7,629,277) describe a fabric laminate formed of high-strength fibers consolidated with from about 7% to about 15% of an elastomeric matrix composition in combination with protective layers of a polymer film on each surface of the fabric.

[0010] There is a need for novel protective and ballistic-resistant materials with improved qualities of abrasion resistance, stability and product handling.

SUMMARY

[0011] The present disclosure relates generally to novel protective materials, assemblies thereof, and to methods by which they are made. More specifically, the present disclosure describes the use of Machine Direction Oriented (MDO) films in the construction of woven or non-woven composites for use in ballistic-resistant or protective articles that exhibit excellent abrasion resistance. The present disclosure also describes composites with high levels of matrix resin that exhibit comparable or improved ballistic performance compared to composites with relatively low levels or matrix resin while also having improved manufacturing, processing and stability properties and being less expensive to produce. In specific constructions, non-woven or UD composites produced with high resin content offers increased value to the end ballistic article manufacturers, since fewer number of number of layers are required for a panel construction relative to an equivalent panel weight produced with low resin content UD.

[0012] In one aspect of the disclosure, it has been determined that protective materials made with MDO polymer film have excellent abrasion resistance properties. In particular, protective materials made with fabric composites laminated with MDO
polymer films are shown to have both excellent and consistent abrasion resistance. In contrast, fabric composites made using regular grade blown polymer films exhibited relatively poor and highly variable abrasion resistance.

[0013] Accordingly, in one embodiment there is provided a ballistic resistant composite comprising one or more layers of a MDO film bound to one or more layers of fabric. In one embodiment, the MDO film is bound directly to the fabric. In one embodiment, MDO film is bound to a consolidated network of fabric in contact with a matrix material. In one embodiment, the fabric is a unidirectional fabric. In one embodiment, MDO film can be laminated to the inter surfaces of a multi-laminate woven or non-woven construction.

[0014] In one embodiment, there is provided a ballistic resistant composite comprising one or more layers of fabrics in contact with a matrix and a MDO
film, wherein the MDO film is laminated to at least a portion of the exterior surface of the composite. The fabric may be a woven fabric or a non-woven fabric. In one embodiment, the fabric is a unidirectional fabric and the fibers of the unidirectional fabric are held in place by the matrix. In one embodiment, the ballistic resistant composite comprises 2 or more layers of unidirectional fabric that are cross-plied such that the fiber direction in adjacent plies is perpendicular.

[0015] In one embodiment, the MDO film is less than 2 mil thick, or less than 0.6 mil thick. Optionally, the MDO film is between 0.25 and 0.75 mil thick. In one embodiment, the MDO film is made of polymeric material such as polyethylene.
In one embodiment, the MDO film has a draw ratio of between 1:2 and 1:10.

[0016] In one embodiment, the ballistic resistant composite comprises a matrix.
In one embodiment, the matrix is an elastomeric resin matrix. In one embodiment, the matrix is a styrene-isoprene-styrene block copolymer, such as those available under the trade-names Prinlin NC, AL and HV. Optionally, the matrix may comprise between 1%
and 75% of the total weight of the composite. In one embodiment, the matrix comprises greater than 15% of the total weight of the composite. In one embodiment, the matrix comprises between 16% and 20% of the total weight of the composite. As used herein the term "total weight of the composite" refers to the dry weight of the high performance fibers that comprise the constituent woven or non-woven fabric and the matrix, and excludes the weight of any additional film layers, such as MDO or other films.

[0017] In one embodiment, the ballistic resistant composites described herein exhibit excellent abrasion resistance. In one embodiment, the ballistic resistant composite when tested according to ASTM D3886-99 exceeds a threshold of 2500 cycles without showing any signs of significant or noteworthy degradation to the MDO
film. In one embodiment, the ballistic resistant composite when tested according to ASTM D3886-99 exceeds a threshold of 2500 cycles without showing a separation of greater than 3 mm in the first layer of fabric yarns adjacent to the MDO film.
In one embodiment, the ballistic resistant composite exceeds a threshold of 5,000 or 10,000 cycles when tested according to ASTM D3886-99.

[0018] In another aspect, there is provided a ballistic resistant article comprises a plurality of the ballistic resistant composites as described herein. In one embodiment, layers of a ballistic resistant composite are stacked or combined to form an article that exhibits a desired level of ballistic protection as is known in the art.

[0019] In another aspect, there is provided a method of producing a ballistic resistant article comprising applying a MDO film onto at least one surface of a consolidated network of one or more layers of fabric in contact with a matrix and laminating the MDO film to the surface of the consolidated network. In one embodiment, the method comprises using heat and/or pressure to laminate the MDO film to the surface of the network. In one embodiment, the method comprises uses an adhesive to laminate the MDO film to the surface of the network.

[0020] In another embodiment, it has surprisingly been determined that composites with a high matrix resin content provide comparable ballistic resistance to composites with lower matrix resin content while at the same time offering improved manufacturing, processing and stability properties and being less expensive to produce.

[0021] Accordingly, in one embodiment there is also provided a ballistic resistant composite comprising one or more layers of high-performance fibers in contact with a resin matrix, wherein the matrix comprises at least 15% of the total weight of the composite. In one embodiment, the matrix: comprises between 15% and 20% of the total weight of the composite. In one embodiment, the matrix comprises between 16%
and 18% of the total weight of the composite. In one embodiment the matrix comprises about 17% of the total weight of the composite. In one embodiment, the resin matrix is an elastomeric matrix.

[0022] Further aspects and advantages of the embodiments described herein will appear from the following description taken together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For a better understanding of the embodiments described herein and to show more clearly how they may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings which show at least one exemplary embodiment, and in which:

[0024] Figure 1 shows a cross section of a ballistic resistant composite according to one embodiment of the present description. 4 layers of unidirectional fabric are cross-plied such that adjacent layers of fibers are perpendicular. The layers of fibers are typically surrounded by a matrix (not shown), which holds the fibers in the desired orientation. MDO film is laminated to the exterior surfaces of the 4-ply UD
composite fabric.

[0025] Figure 2 shows photographs after abrasion testing as set out in Examples 1 and 2 of protective materials made from a unidirectional composite with a regular film (A), unidirectional composite with regular film plus a slip agent (B) and unidirectional composite made with MDO film (C).

DETAILED DESCRIPTION

[0026] It has been determined that the use of machine direction oriented (MDO) film is useful in the construction of protective and/or ballistic-resistant articles. As described herein, high performance fabric composites that comprise MDO films exhibit improved abrasion resistance to comparable composites made using regular films.
Surprisingly, it has also been determined that protective and/or ballistic resistant composites that contain high levels of resin matrix have improved or comparable ballistic-resistant properties when compared to composites that contain relatively less matrix while at the same time offering improved cost, stability, operations efficiency and product handling.

[0027] Accordingly, embodiments described herein include novel ballistic resistant composites that comprise MDO film laminated to one or more layers of fabric, assemblies thereof, their use and methods by which they are made. In one embodiment, the MDO film is bound or laminated to a composite comprising one or more layers of high performance fabric in contact with a matrix.

[0028] Exemplary embodiments make use of fabric made from what are commonly described as high performance fibers. Generally speaking, a high performance fiber is a fiber having a tenacity of about 15 grams per denier and higher, and tensile modulus of at least about 400 grams per denier. Examples are aramid or para-aramid fibers, ultra-high molecular weight polyethylene fibers, poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers, polyolefin fibers, liquid crystal fibers and glass fibers. Aramid and copolymer aramid fibers are produced commercially by DuPont, Teijin Aramid and Teijin under the trade names KevlarTM, TwaronTM, and TechnoraTM
respectively. Ultra-high molecular weight polyethylene fibers are produced commercially by Honeywell, DSM, and Mitsui under the trade names SpectraTM, Dyneema TM, and TekmilonTM, respectively. Polyethylene fibers and tapes are produced by Integrated Textile Systems Inc. and sold under the trade name TensylonTM. Poly(p-phenylene-2,6-benzobisoxazole) (PBO) is produced by Toyobo under the commercial name ZylonTM
Polyolefin fibers are produced under the trade name InnegraTM. Liquid crystal polymers are produced by Kuraray under the trade name VectranTM. As used herein, "fiber" refers to an elongated body for which the length dimension is greater than the transverse dimension or width. The term "fiber" includes filaments, ribbons, strips, or other irregularly shaped fibers with a symmetrical or asymmetrical cross section. In some embodiments, a plurality of fibers running in the same longitudinal direction may constitute a fiber/yarn.

[0029] Other fabrics contemplated for use in embodiments of the protective materials described herein include those made from extended chain polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, and carbon fiber.

[0030] It will be understood that a particular fabric used may be made from a single type of fiber, or from various types of fibers. The fabric may also include various types of fibers in each yarn or in different yarns that are combined to make a fabric layer.

[0031] As used herein, "fabric" or "fabric layer" refers to a plurality of fibers that have been arranged so as to form a continuous sheet. The fabric can be a knitted, woven or non-woven structure or network of fibers. Woven fabrics include any weave such as a plain weave, crowfoot weave, basket weave, satin weave, twill weave, proprietary weaves or the like. The fabric may also be plied, that is, consisting of one or more layers attached together using an adhesive, thermal adhesive, stitching, matrix, or any other method known in the art for combining layers of fabric.

[0032] In one embodiment, the fabric is a non-woven unidirectional (UD) fabric.
As used herein, a "unidirectional fabric layer" refers to a series of fibers combined so as to form a continuous sheet wherein the fibers are all substantially aligned to be parallel in a common longitudinal direction. In one embodiment, the fibers are held in place in a UD fabric using a matrix, resin, film, stitching, knitted fabric or woven fabric or any other method known in the art. In one embodiment, the fibers in a unidirectional fabric layer are held in place by one or two adjacent layers of adhesive MDO film.

[0033] As used herein, the term "composite" refers to a material comprising high performance fibers in contact with a matrix. As used herein, the term "matrix"
refers to a material that contacts and consolidates fibers in a composite. In one embodiment, the matrix is a thermoplastic resin matrix or polymeric resin matrix made from styrenic block copolymers, polyacrylates, polyurethanes, polyisoprene, polyurethane acrylates, styrene-butadiene copolymers, polystyrene acrylates, ethylene-propylene copolymers, nitrile butadiene rubber, polyvinyl butyral, ethylene vinyl acetate copolymer, polyketones, polychloroprene, polyvinyl acetate, polyisobutylene or polyether block amide. In one embodiment, the matrix is a styrene-isoprene-styrene copolymer or resin matrix. In one embodiment, the matrix is an elastomeric matrix. Typically, use of an elastiomeric matrix in a ballistic resistant composite as described herein will result in a flexible composite suitable for use in soft armor applications. Preferred properties for an elastomeric matrix include: tensile modulus < 6,000 psi, tensile strength <
500 psi, elongation > 500 % and Tg (Glass transition) < 0 C.

[0034] In one embodiment, the matrix is a hard ballistic matrix. Typically, use of a hard ballistic matrix in a ballistic resistant composite as described herein will result in an inflexible composite suitable for use in hard armor applications. Preferred properties for hard ballistic matrix include: tensile modulus: > 1000 psi, tensile strength >
500 psi, elongation < 1,000 % and Tg > -30 C.

[0035] Mechanical properties of a matrix can be enhanced by compounding the base polymers with fillers such as carbon black, macro silica, nano silica, nano clay, exfoliated nano clay etc., and may be vulcanized by sulfur, peroxide, metal oxide or UV/EB crosslinking techniques which are well known to rubber technology.
Blends of various elastomeric systems may be used together or one or more elastomer materials may be blended with one or more other thermoplastic matrix systems as known in the art.

[0036] In one embodiment, unidirectional fabrics are produced by impregnating one or more layers of unidirectional fibers with a matrix or thermoplastic resin system as is commonly known in the art. For example, in one embodiment high performance fibers are coated or encapsulated with a matrix that binds the fibers into a consolidated fabric sheet. In one embodiment, two or more layers of unidirectional fabric may be cross-plied together to form a single sheet that can be used in the construction of ballistic articles. The matrix can be applied to the fibers in a number of ways known in the art, such as by bathing, spraying or roll coating the fibers with a matrix solution followed by a drying step. The matrix can also be applied as a gel emulsion in a solvent which later evaporates. The ballistic resistant composites as described herein can be produced with a matrix comprising between 5% and 80% of the total weight of the composite. In a one embodiment, the matrix comprises more than 10%, more than 15%, or between 15% and 20% of the total weight of the composite. In one embodiment, the matrix comprises about 17% of the total weight of the composite. As used herein the term "total weight of the composite" refers to the dry weight of the high performance fibers that comprise the constituent woven or non-woven fabric and the matrix, and excludes the weight of any additional film layers, such as MDO or other films.

[0037] As used herein, a "machine direction oriented film" or "MDO film"
refers to a film made from a polymer or blend of polymers that has been strained under a uni-axial stress such that the polymers in the film become aligned in the direction of the stress.

[0038] In some embodiments, the machine direction oriented (MDO) film consists of film produced by orienting cast extrusion films. For example, a film of molten polymer may be extruded onto a chill roll, which quenches it into an amorphous state.
The film may then be uniaxially oriented by drawing the film in the 'machine direction' such as by using heated rollers or in a heated oven.

[0039] Machine direction oriented (MDO) films have enhanced physical properties compared to randomly-oriented polymer films due to their linear molecular orientation. Subjecting a polymer film to a uni-axial stress results in the polymer molecules becoming oriented in the direction of the pull.

[0040] Other methods of producing MDO films include first performing a method known in the art for producing a film such as calendering, cast-extrusion, cast-co-extrusion, blown-film extrusion or blown film co-extrusion followed by stretching the film.
In one embodiment, the film is stretched by feeding it through a series of differential draw rolls, wherein the rolls are running at gradually increasing speeds. In some embodiments the rolls are heated so as facilitate the stretching process. In some embodiments, the film is cooled after stretching in order to set the orientation of the film.
The film may be drawn just once, or multiple times. Examples of commercially available MDO orientation systems include those available from Eclipse Film Technologies, Hamilton, Ohio, USA such as XEO-07014B and XEO-07014.

[0041] MDO films can be made from polymers or copolymers known in the art such as, but not limited to, polyolefins, polyethylene, polypropylenes, polyurethanes, polyesters, polyether esters, polyamides, ethylene-vinyl acetate copolymers, polyvinyl chloride, poly vinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polystyrene, ethylene vinyl alcohol copolymers, ethylene-propylene-butylene terpolymer, ethylene butyl acrylate copolymers or polymonochlorotrifluoroethylene and all practical polymeric-film materials.

[0042] In one embodiment, the MDO film has a thickness of less than 2 mil.
Optionally, the MDO film has a thickness of less than 0.6 mil, less than 0.35 mil, or less than 0.25 mil. In one embodiment, the MDO film has a thickness of about 0.5 mil.

[0043] In one embodiment the draw ratio of the MDO film is between 1:1.5 and 1:20. In one embodiment, the draw ratio of the MDO film is between 1:2 and 1:10, or between 1:3 and 1:8. A person of skill in the art will appreciate that a suitable draw ratio for an MDO film will depend on the constituent polymer used to manufacture the film.

[0044] In one embodiment, there is provided a ballistic-resistant article comprising at least one unidirectional fabric layer and at least one MDO film, wherein the MDO film is attached to at least a portion of an exterior surface of the composite.

[0045] The layers that constitute the ballistic resistant composites described herein may be bound or laminated together by various techniques known in the art, such as the application of an adhesive between the layers, the application of heat and/or pressure, or physically attaching the layers such as by stitching or needle punching the layers. The layers of the invention may also be secured together through a combination or plurality of means.

[0046] In one embodiment, the MDO film is laminated to a composite. As used herein, "laminated" refers to contacting two surfaces such that they adhere to one another. In one embodiment, the MDO film is laminated to the composite by contacting the surface of the film with the composite and applying heat and/or pressure.
In one embodiment, the film and composite adhere through the action of the matrix which contacts and adheres to the MDO film. For example, the fabric can comprise a coating or matrix which acts as the binding agent for laminating the fabric to MDO
film when heat and/or pressure is applied to the MDO film and UD fabric. In one embodiment, low modulus elastomeric binders, tackifiers and/or resins are utilized to laminate the MDO film to the fabric or composite.

[0047] In one embodiment, the MDO film is bound to a fabric layer or to composite using an adhesive. For example, in one embodiment the MDO film is coated with an adhesive on one side of the film and the coated side is then applied to the surface of the composite or fabric layer. In one embodiment, the composite or fabric layer may be coated with a suitable adhesive before applying the MDO film to the surface of the fabric.

[0048] The MDO films can be bonded or laminated to the surface of a composite or to a fabric layer in any orientation. For example, when the fabric layer is a UD fabric, the axial orientation of the MDO film and direction of fibers in an adjacent UD layer can be at any angle. For instance, a UD layer can be laminated with a MDO film such that the molecular orientation of the film is perpendicular to the fiber orientation in the UD
layer. The weakest point of a single (monolayer) unidirectional layer is the direction perpendicular to the fiber direction. The use of MDO film may therefore strengthen the horizontal or transverse stability (90 degree stability, direction perpendicular to the fibers) of a UD layer. In one embodiment, the axial direction of the MDO film and fiber direction in an adjacent UD layer are rotationally offset, such as at 0 degrees, 45 degrees or at 90 degrees.

[0049] In some embodiments, it is also advantageous to pretreat the composite, the fabric (or alternatively the fibers from which the fabric is made) to allow the MOO
film or matrix to better adhere to the fabric layer or composite. For example, the fabric or composite may be plasma treated, corona treated, scoured or subject to other types of pretreatment.

[0050] It will be appreciated that in one embodiment the ballistic articles described in the present application consist of a single layer of MDO film attached to a single layer of fabric, such that the MDO film is only found on one side of the fabric.
Alternatively, MDO film may be laminated or bound to both sides of a fabric.
In some embodiments, the MDO film is bound to only a portion of a layer of fabric.

[0051] Other embodiments include constructions where multiple layers of fabric are laminated between adjacent layers of MDO film. The embodiments in this describe herein also include those made from different combinations of MDO film and fabric. For example in one embodiment layers of MDO film can be interspersed with layers of unidirectional fabric. Often, at least one external layer of the article will be a layer of MDO film.

[0052] Figure 1 shows one embodiment of a ballistic resistant composite consisting of a six-layer laminate made with four plies of unidirectional fabric and two exterior layers of MDO film. Typically, the plies of unidirectional fabric are contained within a matrix (not shown). A layer of MDO adhesive film is bound to each of the external surface layers of the article. In one embodiment, layers of unidirectional fabric are cross-plied such that the direction of the high performance fibers in adjacent layers of UD fabric are perpendicular to one other. Optionally, the machine direction of the film is perpendicular to the fiber direction in the adjacent unidirectional fabric layer.

[0053] In one embodiment, the MDO film is used to bind single plies of UD
material or any combination of layers in a multiply material. In one embodiment, the MDO film is the outer surface layer of a multi-laminate UD construction. In one embodiment, a plurality of layers of fabric are consolidated together in a matrix or resin and MDO film is then bound or laminated to the exterior fabric surfaces of the consolidated network.

[0054] Several advantages flow from the embodiments described herein. In one embodiment, the composites described herein exhibit improved abrasion resistance. As shown in Example 4, the ballistic performance of composites made with MDO film is comparable to that of composites made with regular film, while also having improved abrasion resistance.

[0055] In some embodiments, the reduced thickness of the MDO film compared to other film laminates reduces the overall thickness and weight of a ballistic article. In other embodiments, articles made according to the present description benefit from increased resistance to ballistic impacts.

[0056] As known in the art, fabric constructions may be tested for abrasion resistance according to American Society for Testing and Materials (ASTM) standard ASTM 3886-99. Fabric constructions used in protective garments should generally exceed a threshold of 2000 cycles when tested according to ASTM D3886-99 using an inflated diaphragm apparatus. As shown in Examples 2 and 3, abrasion testing of articles made with MDO film according to ASTM D3886-99 not only surpassed the cycle limitation, but even after more than 10,000 rotations ballistic articles produced using MDO showed no signs of deterioration. No noticeable tears, holes or pores were formed in the 0.5mil MDO film during the various abrasion tests performed, as a results the fibers in the UD construction adjacent to the MDO outer layer were not impacted.
Furthermore, with MDO film consistent and repeatable abrasion results were achieved when compared to regular blown polymer films. Protective materials made using regular grade films rarely passed the 2000 cycle requirement and even if a product passed the 2000 cycle requirement, repeatability of success was random and low.
Additionally, those samples that passed still showed fiber degradation and gaps of less than 3mm or close to 3mm are formed by the time samples are exposed to 2000 rotations. In some cases, UD laminated with regular polyethylene film degraded with as little as rotations.

[0057] Figure 2 shows photographs samples after abrasion resistance testing of (A) U500-Regular film material, (B) U500-Regular film with a slip agent and (C) U500-MDO film. Significant fiber degradation is observed in the samples made from laminated with "Regular" film, as well as U500 laminated with "Regular" film with a precipitated calcium carbonate slip agent known under trade name Albaglos .
Samples comprising U500 laminated with MDO film (C) did not show degradation of fibers and the formation of gaps, and the film was still intact on the surface of the article.

[0058] In some embodiments the MDO film also acts as a barrier to water and other materials that may negatively affect the ballistic performance of the fabric layer.

[0059] In one embodiment there is provide articles comprising a plurality of ballistic resistant composites as described herein arranged in a stack. In one embodiment, the protective materials described herein comprise a slip agent between adjacent layers of materials in a stack. For example, layers of ballistic resistant composites can be arranged in a 'stack' and combined, such as in an envelope or by point stitching around the periphery, to allow for relative movement of adjacent layers for use in soft-armor applications. In other embodiments, the ballistic resistant composites described herein can be combined and used in hard-armor applications.

[0060] Articles that may benefit from being manufactured from the ballistic resistant composites described in the present application include, but are not limited to, soft body armor, hard personal armor plates and shields, vehicle armor, bomb blankets and suits, mine clearance suits, helmets, electrical blast suppression blankets, fragmentation vests, firefighters' turn-out gear, heat and flame resistant work-wear, articles for knife protection, articles resistant to penetration by sharp objects, chainsaw chaps and cut resistant aprons.

[0061] While the above description includes a number of exemplary embodiments, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes.

[0062] The following non-limiting examples are illustrative of the present invention:

EXAMPLES
Example 1: Abrasion Resistance of U500 Protective Materials With and Without Slip Agents.

[0063] Samples of UD protective materials were tested according to ASTM
D3886-99 (Stoll Abrasion Test Method) using an inflated diaphragm apparatus with the following parameters:

= Load: 51b = Pressure: 4 psi = Abradant: Against itself = Type of Abrasion: Multidirectional

[0064) Two samples are required for the Stoll Abrasion Test Method (ASTM
3886-99). A circular piece is mounted on an inflated diaphragm apparatus, which rotates 360 degrees for the duration of the test. The second piece is a rectangular sample, which is mounted to the test apparatus and moves longitudinally for the duration of the test. The circular and rectangular pieces are abraded against each other and the number of cycles to wear is recorded. The more cycles a set of samples can tolerate without generating any gaps or signs or product deterioration the greater the abrasion resistance properties of a fabric.

[0065] Samples of U500 composite UD material were tested for abrasion resistance both with and without the use of an AlbaglosTM slip agent.

[00661 "Regular" U500 composite UD is a multiply unidirectional product produced using Kevlar K129 fiber 1580dtex in 0/90/0/90 configuration with two 0.25 mil polyethylene thermoplastic films laminated to the outer surfaces. The final configuration of the product is f/0/90/0/90/f, where 0/90/0/90 refers to consolidation angle of the mono UD layers and "f' refers to film. "Regular" U500 product construction is made with 0.25mi1 regular polyethylene film.

[0067] As shown in Table 1, the use of a slip agent did not generally show any significant improvement in the abrasion resistance of the material.
Furthermore, although some of the U500-Regular test samples exceeded the 2000 cycle threshold, these samples showed wear although gaps of greater than 3 mm were not formed in the test sheet. In other samples, abrasion testing rapidly led to the degradation of the fabric layer and gaps of greater than 3 mm in as few as 24 cycles.

Test No. Circular Rectangular Fiber Number of Tested Sample -(No. of Piece - Piece - Film Direction of cycles Physical Observation samples) Film Type Type Rectangular fabric Piece withstood without degrading 1 (5) U500 A - U500 A - 0 Degree 200 All samples showed Regular Regular (slip >2500 * film wear and formation (slip agent) agent) 630 of gap in top UD sheet.
Top UD sheet is the 201 layer adjacent to film.
240 Level of deterioration was same in rectangular and circular test pieces. *Test terminated after 2500 cycles.
2 (5) U500 A - U500 A - 90 Degree 205 Rectangular pieces Regular Regular (slip 200 deteriorated easily -(slip agent) agent) 230 film and top UD layers fell apart.

3 (5) U500 - U500 - 0 Degree >2500 Both rectangular and Regular Regular >2500 circular pieces showed >7765 wear, however gap of >3mm was not formed >2500 in UD sheet.
>2500 4 (5) U500 - U500 - 90 Degree >2500 Both rectangular and Regular Regular >2500 circular pieces showed > 2540 wear, however gap of >3mm was not formed > 2511 in UD sheet.
>2500 (5) U500 - U500 - 0 Degree 125 Both rectangular and Regular Regular 752 circular pieces showed 181 wear. Sample that survived >2500 204 rotations: showed film >2500 wear and gap started to form, however it was less than 3mm. Test terminated after 2500 cycles.
6 (5) U500 - U500 - 90 Degree 24 Both rectangular and Regular Regular 115 circular pieces showed wear, however gap of 106 >3mm was not formed 241 in UD sheet.

Table 1: Abrasion testing of U500-Regular and U500-A (slip agent) laminates Example 2: Comparative Testing of U500 and U500-MDO

[0068] Abrasion testing was performed on samples of protective laminates comprising Regular U500 fabric made with polyethylene film (2 x 0.25 mil, end construction f/0/90/0/90/f) and U500 UD fabric made with MDO film (2 x 0.5 mil, end construction F/0/90/0/90/F). Testing was performed according to ASTM D3886-99 using an inflated diaphragm apparatus with the following parameters:

= Load: 51b = Pressure: 4 psi = Abradant: Against itself = Type of Abrasion: Multidirectional [0069] Testing was performed until the 1st layer of fabric yarns separated at 3 mm in width before or at 2500 cycles, whichever came first. Samples were tested using both the low (side "A") and high (side "B") resin sides abrading against the low and high resin sides of the test samples. The low resin side refers to the side where the UD fibers have less resin compared to its opposite side due to the settling of resin to the bottom side of the layer as the layers of UD are formed. Film is lightly adhered to the low resin side, whereas on the opposite side (the high resin side) the bond between film and UD
is relatively stronger. Results are shown in Tables 2 and 3.

Test No. Circular Rectangular Fiber Number of Tested Sample -(No. of Piece - Piece - Film Direction of cycles Physical Observation samples) Film Type Type Rectangular fabric Piece withstood without degrading 3(3) U500 - U500 - 0 Degree >2500 Regular Regular only tested >2500 Both rectangular and (Side A to A) >2500 circular pieces showed wear. Film degraded 3 (3) U500 - U500 - 0 Degree >2500 and fibers showed Regular Regular only tested >2500 signs of degradations.
(Side A to B) >2500 Gaps began to form, however due to 3 (3) U500 - U500 - 0 Degree 198 filament entanglement Regular Regular only tested >2500 gap of >3mm was not (Side B to B) >2500 formed. Test 3(3) U500 - U500 - 0 Degree 144 terminated after 2,500 cycles Regular Regular only tested >2500 (Side B to A) >2500 Table 2: Abrasion testing of U500-Regular film laminates Test No. Circular Rectangular Fiber Number of Tested Sample -(No. of Piece - Piece - Film Direction of cycles Physical Observation samples) Film Type Type Rectangular fabric Piece withstood without degrading 3 (3) U500 - U500 - MDO 0 Degree >2500 Consistent MDO only tested >2500 performance achieved (Side A to A) >2500 with all 12 samples.
Film showed no signs 3 (3) U500 - U500 - MDO 0 Degree >2500 of wear. No impact on MDO only tested >2500 fibers.
(Side A to B) >2500 3 (3) U500 - U500 - MDO 0 Degree >2500 MDO only tested >2500 (Side B to B) >2500 3 (3) U500 - U500 - MDO 0 Degree >2500 MDO only tested >2500 (Side B to A) >2500 Table 3: Abrasion testing of U500-MDO test samples [0070] Remarkably, all of the U500-MDO samples tested exceeded the test endpoint of 2500 cycles and showed no signs of wear. In contrast, both the circular and rectangular U500-Regular test pieces showed wear and both the film and fibers showed signs of degradation. Furthermore, while a number of the U500-Regular samples passed the 2500 cycle endpoint, gaps began to form, however due to filament entanglement these gaps were less than 3 mm.

Example 3: Additional Testing of UD-MDO Laminates [0071] Additional abrasion testing was performed on samples consisting of U500-Regular (f/0/90/0/90/f where f=0.25mi1 regular PE film), U500-MDO with film on both sides (F/0/90/0/90/F where F=0.5mil MDQ PE film) and U500-MDO with film on one side (F/0/90/0/90, where F = 0.5mil MDO PE film) protective laminates. Testing was performed according to ASTM D3886-99 using an inflated diaphragm apparatus with the following parameters:

= Load: 51b = Pressure: 4 psi = Type of Abrasion: Multidirectional [0072] Samples of U500-MDO were abraded against U500-Regular, U500-MDO
against U500-MDO as well as the film side of U500 MDO film laminated on one side abraded against the fiber side of a piece of U500-MDO also laminated on one side.
Results are shown in Table 4.

Test No. Circular Rectangular Fiber Number of Tested Sample -(No. of Piece-Film Piece-Film Direction of cycles fabric Physical Observation samples) Type Type Rectangular withstood Piece without degrading 4 (2) U500 - U500 - 0 Degree >2500 Film degradation on both MDO Regular samples was noted, however damage to fibers was noted.

90 Degree 1210 90degree (U500-Regular): both film and UD layer deteriorated.
4 (2) U500 - U500 - MDO 0 Degree >10,000 No degradation to film or MDO fibers noted on both samples.
90 Degree >10,000 No degradation to film or fibers noted on both samples.
4 (2) U500 - U500 - 0 Degree >10,000 No degradation noted on MDO with MDO (fiber circular test piece.
film side facing Minor filamentation laminated circular formed on rectangular on one side piece) test piece, however no only film gap was formed.
side tested) 90 Degree >10,000 No degradation noted on circular test piece.
Rectangular piece deteriorated (one layer only) Table 4: Additional testing of U500-MDO and U500-Regular laminates [0073] Abrasion testing between articles that were both covered with MDO film showed no or only very minor degradation of the film or fibers in the UD
fabric. UD
samples tested for abrasion with the fiber direction of the rectangular piece at 90 degrees degraded more quickly that samples with the fiber direction of the rectangular piece at 0 degrees. Testing of samples with the fiber direction of the abrading surface layer of the rectangular piece at 90 degrees to the direction of the abrading movement generally results in lower abrasion resistance due to the relative weakness of a UD
layer in an axis perpendicular to the fiber direction.

[0074] However, samples with laminated with MDO film showed excellent abrasion resistance with the fiber direction of the abrading surface layer at both a 0 degree orientation and a 90 degree orientation.

Example 4: Ballistic Testing of Composites Made with MDO film or Regular Film [0075] UD composites laminated with either MDO polyethylene film or regular polyethylene film were tested for ballistic resistance (V50 values) with either 9 mm Remington or .44 magnum Speer projectiles. V50 refers to the ballistic caliber velocity at which 50 percent of the shots are expected to penetrate a given article and the remaining 50% of shots are expected to be stopped by the ballistic resistant article. The higher the V50 value, the greater the resistance properties of a ballistic article.

[0076] Each UD composite layer consisted of 4 plies of UD Twaron 2000 1100 dtex fiber cross-plied in a 0/90/0/90 configuration with a styrene-isoprene-styrene block copolymer resin matrix comprising 17% of the total weight of the composite.
0.25 mil layers of regular polyethylene film were laminated to each side of the Regular-UD
samples, while one 0.5 mil layer of MDO polyethylene film was laminated to a single side of the MDO-UD samples.

[0077] As shown in Table 5, V50 values were determined for shoot packs consisting of 15 layers (9 mm Remington) or 24 layers (44 magnum Speer) of stacked UD composites. The ballistic performance of UD composites laminated with MDO
film is comparable to that using regular film. However, as shown in Examples 2 and 3, UD
laminates produced using MDO film have better abrasion resistance compared to UD
laminates produced with regular film. Penetration and ballistic-resistant materials made using MDO film therefore offer improved abrasion resistance without comprising ballistic performance.

Layers V50 STD Dev Abrasion m/s m/s Resistance 9mm FMJ Remington U006 17% Regular Film 15 493 12 Low & High Variability U006 17% MDO 15 480 1 High & Consistent .44 magnum Speer U006 17% Regular Film 24 512 12 Low & High Variability U006 17% MDO 24 498 10 High & Consistent Table 5: Ballistic testing of UD composites made with regular or MDO
polyethylene film Example 5: Ballistic Testing of UD Composites made with High (17%) or Low (13%) Matrix Resin Content [0078] Ballistic testing to determine V50 values was performed on shoot packs of equal areal density with UD composites consisting of either 13% or 17% by weight of styrene-isoprene-styrene resin matrix. Each UD composites consisted 4 plies of UD
Twaron T2000 1100 dtex fiber cross-plied in a 0/90/0/90 configuration and laminated on both exterior surfaces with 0.25 mil regular polyethylene film. Testing was performed with 9mm FMJ Remington and .44 Magnum Speer projectiles. Although, the panel weights of shoot packs produced using both low (13%) and high (17%) resin content UD
are relatively equal, test panels produced using low resin content UD consist of one more layer than panels produced with UD using high resin content.

Panel STD DEV
Layers Weight V50 (m/s) [PSF] (m/s) 9mm FMJ Remington 0006 13% A506 16 0.78 486 13 0006 A 17% A560 15 0.76 471 16 0006 B 17% A712 15 0.76 493 12 .44 magnum Speer 0006 13% A506 25 1.22 491 2.8 0006 A 17% A560 24 1.22 503 16 0006 B 17% A712 24 1.22 512 12 Table 6: Ballistic testing of low (13%) and high (17%) matrix resin content UD
composites.

[0079] As shown in Table 6, the high resin content composite resulted in comparable or even improved ballistic performance compared to the lower resin content composite with an additional layer. The generic perception and industry goal within the ballistic market is to minimize resin content in order to optimize performance.

[0080] Notably, an equivalent panel weight consisting of a UD construction made with high resin content also has significant cost advantages. In Table 6, the panel weights of low resin content and high resin content UD are equivalent; however panels with high resin content UD consist of one less layer. This also means that panels produced using with high resin content UD have higher percentage of resin to fiber ratio.
Unit fiber costs are significantly higher than unit resin cost; typically fiber is 3x to 20x more expensive than resin. As a result, having a higher proportion of resin within a panel weight also presents significant cost advantages.

[0081] Additionally, UD constructions produced using higher resin content may be desired in that they can offer increasing manufacturing handling and processing benefits. UD constructions are inherently difficult to handle and process, especially monolayer UD sheets due to their intrinsic weak transverse bonds. Secondly, the adhesion of monolayer to release linear is a strictly controlled parameter in production and lack of adhesion between monolayer UD and release linear can often lead to production downtime and increase cost of quality. UD constructions produced using higher resin content offer increased product integrity and increased bond between UD
and release linear. The increased adhesion can reduce probability of the entire monolayer or segments of monolayer disconnecting from the release linear and therefore reduce changes of production downtime and production of defective materials.
[0082] Furthermore, a wide range of processes can be utilized to produce UD
monolayers and various 0/90 and 0/90!0/90 constructions with or without film.
A
commonly preferred method of producing UD monolayers involves coating fibers with resin distributed in a substantially encapsulated manner, inferring that all individual filaments within the monolayer must be coated by the resin and the resin must be homogenously distributed across the monolayer thickness. Typically from a manufacturing and product construction perspective, it is desired to have each outer surfaces of a monolayer contain resin deposit. A monolayer has an exposed outer surface and an inner surface which is laminated to a carrier release linear.
It is desirable to have resin or tack on both outer and inner surfaces of a monolayer. Resin or tack on the outer layer is desired in order to laminate one outer surface of a monolayer to another outer surface of a second monolayer to produce a 0/90 or 0/90/0/90 or various multiples of 2 ply construction. Resin or tack on inner surface is desired to have sufficient bond between monolayer and release linear in order to form a continuous monolayer construction that can be converted into a usable final construction.

[0083] The level of resin distribution across a monolayer can vary significantly. In one case, it is possible to produce monolayer construction with distinctive differences in resin deposit across outer and inner surfaces of a monolayer. This attribute can be described as gradient resin distribution across a monolayer thickness, where the outer surface as minimal or no resin deposit and inner surface as maximum resin deposit. In the most extreme case, the outer surface has no resin deposit. Furthermore, in a variation of the extreme case multiple filament layers immediately below the outer surface has no resin deposits.

[0084] A monolayer produced with gradient resin distribution may be assumed to have undesirable surface attributes, since cohesion between two outer surfaces of adjacent layers is typically inadequate from consolidation and processing perspectives.
Surprisingly, UD monolayers produced using resin gradient may provide equivalent ballistic performance as UD produced with more evenly distributed resin. As long as the final 0/90 or 0/90/0/90 or any combination of 2 ply construction with or without film has a sufficient amount of resin distributed between the interfaces of the two ply bond, a monolayer with gradient resin distribution may not necessarily be a negative attribute.
Manipulation of monolayer may be required to ensure sufficient resin is present between adjacent monolayer interfaces and resin distribution across multiple interfaces is equal.

[0085] UD produced using high resin content (i.e. greater than 15% of the total weight of the composite) may also be a beneficial for monolayer constructions produced using gradient resin distribution. The primary means of ensuring adhesion between monolayers is to manipulate UD monolayers to ensure outer surfaces are laminated to inner surfaces. As a result, the primary binding mechanism is to combine the relatively higher resin deposit surface with no or low resin deposit surface. Monolayers with overall higher resin content compared to monolayers with lower resin content have relatively higher resin deposits on the outer surfaces, which further contributes to the adhesion of outer and inner surfaces of monolayers produced with gradient resin distribution.

[0086] Since the primary binding mechanism when working with monolayers produced using gradient resin distribution is to combine the relatively higher resin deposit surface with no or low resin deposit inner surface, the resin's adhesive nature or tackifying attributes of a resin system are secondary. Consequently, a tackifier or high tack resins may not be necessary when cross ply UD constructions are produced using monolayers with high resin content and gradient resin distribution method.

[0087] Furthermore, the use of high resin content and gradient resin distribution may increase the selection of resins that are suitable for unidirectional constructions when laminating monolayers. Typically a critical screen factor when identifying resin system for unidirectional or non-woven systems is the resin's adhesive nature or tackifying abilities. With overall high resin content UD and the resin gradient distribution method, resin selection may not be limited to resins with high tack.
Additional advantages of producing UD with high resin matrix content include:
improved adhesion to carrier release linear compared to lower resin content UD;
improved monolayer stability during the cross plying stage since fibers within the monolayer are more securely held; and improved cross ply or cross lamination operations efficiencies Example 6: Stability Testing of High and Low Resin Content UD Composites [0088] Samples of high (17%) and low (13%) matrix resin content UD composites are tested for stability using a 10 day tumbling protocol according to National Institutes of Justice (NIJ) protocol NIJ 06. The NIJ tumbler study involves placing ballistic articles in an environmental chamber that is rotated in a clockwise direction (similar to clothing dryer). Ballistic articles are tumbled for 10 days or approximately 72,000 +
1,500 rotations. Typically 15 to 20 ballistic articles are processed in one tumble study;
meaning 15 to 20 tumbled are processed in one rotating environmental conditions chamber at the same time. The typical conditions used for accelerated aging and tumble studies are 65C and 80% relative humidity.

[0089] The UD composites for testing consist of 4 plies of UD Twaron T2000 1100 dtex fiber cross-plied in a 0/90/0/90 configuration and laminated on both exterior surfaces with 0.25 mil regular polyethylene film. The UD composites were prepared with either 17% or 13% of a styrene-isoprene-styrene block copolymer matrix.

[0090] It is expected that the high resin content samples exhibit better stability over the course of the test and retain structural integrity. In contrast, it is expected that the low resin content samples are more prone to delamination and other structural failures. The fibers within the high resin content UD construction are more firmly positioned and adhesion between adjacent mono UD layers is enhanced due increased quantity of resin. During the tumbling process, the structural integrity of ballistic articles becomes a critical factor, since during the duration of the tumble test panels are constantly colliding with other test panels within the chamber and panels are tossed around in the chamber. As a result, unidirectional ballistic material produced using high resin content may retain product integrity better during the tumble test. High resin content UD may also prevent excessive delamination of laminated monolayer during the tumble test, which is a critical product integrity variable monitored during long-term stability assessments.

Claims

1. A ballistic resistant composite comprising one or more layers of fabric in contact with a matrix laminated to at least a portion of one or more layers of a machine direction oriented (MDO) film less than 2 mil thick, wherein the MDO
film is laminated to an exterior surface of the composite.

2. The ballistic resistant composite of claim 1, wherein the fabric is a woven fabric.

3. The ballistic resistant composite of claim 1, wherein the fabric is a non-woven fabric.

4. The ballistic resistant composite of claim 3, wherein the fabric is a unidirectional fabric.

5. The ballistic resistant composite of claim 4, wherein the unidirectional fabric comprises a plurality of fibers held in place by the matrix.

6. The ballistic resistant composite of claim 1, comprising 2 or more layers of a unidirectional fabric that are cross-plied such that the fiber direction in adjacent plies is perpendicular.

7. The ballistic resistant composite of claim 1, wherein the MDO film is less than 0.6 mil thick.

8. The ballistic resistant composite of any one of claims 1 to 7, wherein the MDO
film comprises a material selected from polyethylene, polyvinylchloride, EVOH, nylon and polypropylene.

9. The ballistic resistant composite of any one of claims 1 to 8, wherein the fabric comprises a material selected from aramid fiber, extended chain polyethylene fiber, poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers, glass fibers and liquid crystal polymer-based fiber.

10. The ballistic resistant composite of any one of claims 1 to 9, wherein the matrix comprises an elastomeric resin selected from styrenic block copolymers, polyacrylates, polyurethanes, polyisoprene, polyurethane acrylates, styrene-butadiene copolymers, polystyrene acrylates, ethylene-propylene copolymers, ethylene acrylic acid copolymer, nitrile butadiene rubber, polyvinyl butyral, ethylene vinyl acetate copolymer, polyketones, polychloroprene, polyvinyl acetate, polyisobutylene and polyether block amide.

11. The ballistic resistant composite of claim 10, wherein the matrix is a styrene-isoprene-styrene block copolymer.

12. The ballistic resistant composite of any one of claims 1 to 11, wherein the MDO film has a draw ratio of between 1:2 and 1:10.

13. The ballistic resistant composite of any one of claims 1 to 12, wherein the matrix comprises greater than 15% of the total weight of the composite.

14. The ballistic resistant composite of claim 13, wherein the matrix comprises between 16% and 20% of the total weight of the composite.

15. The ballistic resistant composite of any one of any one of claims 1 to 14, wherein when tested according to ASTM D3886-99 the composite exceeds an abrasion resistant threshold of greater than 2,500 cycles without a separation of greater than 3 mm in a first layer of fabric yarns adjacent to the MDO film.

16. A ballistic resistant article comprising a stack of a plurality of the ballistic resistant composites of any one of claims 1 to 15.

17. A method of producing the ballistic-resistant composite of any one or claims 1 to 16, the method comprising applying a machine direction oriented film onto at least one exterior surface of a consolidated network of one or more layers of fabric and a matrix;
laminating the machine direction oriented film to the consolidated network.