Patent Application
20210172711
The present disclosure is directed to a ballistic panel and method of making the ballistic panel.
Ballistic panels are often used in applications where bullet proofing is desired. A conventional ballistic panel includes a multi-ply laminate of Kevlar fabric in a non-symmetric panel construction as shown in
The current panel of
Thus, there is a need in the art for materials and processes that can provide a ballistic panel that can be manufactured with reduced warping and less scrap while employing hot bonding methods.
The present disclosure is directed to a ballistic panel. The ballistic panel comprises a core layer having a first major surface and a second major surface, the core layer comprising a ballistic resistant material. A first layer comprising a ballistic gel material is disposed on the first major surface of the core layer. A second layer comprising a ballistic gel material is disposed on the second major surface of the core layer.
The present disclosure is also directed to a method of making a ballistic panel. The method comprises providing a core layer having a first major surface and a second major surface. The core layer comprises a ballistic resistant material. A first layer comprising a ballistic gel material is attached on the first major surface of the core layer. A second layer comprising a ballistic gel material is attached on the second major surface of the core layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present teachings, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects of the present teachings and together with the description, serve to explain the principles of the present teachings.
It should be noted that some details of the figures have been simplified and are drawn to facilitate understanding rather than to maintain strict structural accuracy, detail, and scale.
Reference will now be made in detail to the present teachings, examples of which are illustrated in the accompanying drawings. In the drawings, like reference numerals have been used throughout to designate identical elements. In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustration specific examples of practicing the present teachings. The following description is, therefore, merely exemplary.
The ballistic panel, as shown in
The symmetric designs of the ballistic panels of the present disclosure reduce warping to within acceptable levels while still allowing fabrication by the hot bonding method. Hot bonding employs relatively high temperatures, such as, for example, above 200° F., such as from about 220° F. to about 500° F., which can increase production rates. In an example, the hot bonding can occur at temperatures of from about 275° F. to about 300° F. for 25-30 minutes at 80 PSI. Ballistic gel layers comprising, for example, cells filled with ballistic gel, or other ballistic gel layer materials as described herein, are adhered to a multi-ply laminate of ballistic resistant material to provide for a single, cohesive laminate structure that achieves desired ballistic protection. In an embodiment, the ballistic gel layer comprising cells filled with ballistic gel has a lower density than, for example, a Kevlar laminate, thereby providing a relatively lightweight ballistic material.
The ballistic resistant material that may be used for core layer 102 will now be described in more detail. An example of a suitable material is para-aramid fibers, such as KEVLAR (poly paraphenylene terephthalamide) fibers, woven into a fabric and impregnated with a curable resin. In the KEVLAR fibers, the aromatic groups are all linked to the backbone chain at the 1 and 4 positions, as shown in Formula 2, below, where “n” is the number of repeat units. This is called a para-linkage.
Multiple layers, or plies, of the resin impregnated KEVLAR fiber fabric can be laminated together with the resin and cured. For example, about from 5 to about 20 plies, such as from about 10 to about 20 plies, or from about 10 to about 15 plies of resin impregnated fabric can be included in the core layer 102. The resin can be any curable resin that is suitable for such pre-impregnated laminates, such as an epoxy resin. The resin can be a low heat release resin, including thermosetting resins such as phenolic resin, benzoxazine resins, and cyanate ester based resins. Thermoplastic resins such as Polyether ether ketone (PEEK), Polyetherketoneketone (PEKK), Polyphenylsulfone (PPSU), Polyphenylene sulfide (PPS), and Polyetherimide (PEI) resins can also be used.
The thickness of the core layer 102 can be chosen to provide a desired degree of protection against penetration of the ballistic panel 100 by bullets or other projectiles. As examples, the core layer 102 can have a thickness ranging from about 0.1 inch to about 0.5 inch, such as from about 0.2 inch to about 0.4 inch.
Both the first layer comprising ballistic gel material 120 and the second layer comprising ballistic gel material 122 can comprise a cell wall 108 structured to provide a plurality of cells 110. A ballistic gel 112 is embedded within the plurality of cells 110 to form cellular gel-filled layers.
The ballistic gel 112 can be any dilatant, non-newtonian fluid that has the property of exhibiting an increase in rigidity when impacted by a bullet. An example of such a ballistic gel is D3O™ gel, commercially available from D3O Labs of London, United Kingdom. D3O is an energy-absorbing gel material comprising polyurethane and polyborodimethylsiloxane. The D3O can be in the form of a foam, such as closed cell polyurethane foam composite comprising polyborodimethylsiloxane (PBDMS) as the dilatant dispersed through the foam matrix.
The cell walls 108 provide little or no ballistic resistance without the D3O gel, but do impart stiffness to the composite panel. The first layer comprising ballistic gel material 120 and the second layer comprising ballistic gel layer 122 can each have any thickness that provides the desired ballistic resistance and/or stiffness to the ballistic panel. As an example, the thickness can range from about 0.2 inch to about 3 inches, such as from about 0.2 inch to about 2 inches, or from about 0.5 inch to about 1 inch.
The ballistic panel of
The first face sheet 130 and the second face sheet 132 can have any desired thickness. Examples of suitable thickness range from about 0.005 inch to about 0.04 inch, such as from about 0.01 inch to about 0.03 inch.
One or more of the layers that make up the ballistic panel 100 can be attached together using adhesive layers. For example, a first adhesive layer 150 can adhere the first layer of ballistic gel material 120 to the core layer 102 and a second adhesive layer 150 can adhere the second layer of ballistic gel material 122 to the core layer 102. Other adhesive layers 150 can be used to adhere the face sheets 130,132 to the ballistic panel 100. Any suitable adhesive material that provides sufficient bonding between the layers can be employed. Examples include urethane adhesives and epoxy adhesives.
Other implementations of the ballistic panels of the present disclosure are contemplated. As examples, instead of the cellular gel-filled layers discussed above for the layers 120 and 122 of
Various other layers can also optionally be employed in any of the ballistic panels described herein. For example, the ballistic panels of
The fire retardant layers can comprise one or more layers, such as about 1 to about 10 layers, or about 1 to about 5 layers, or about 1 to about 3 layers, of fabric impregnated with a fire retardant. The fabric can be a ballistic resistant material, such as woven para-aramid fibers (e.g., KEVLAR® or other fabric). Any suitable fire retardant material can be employed, such as any of the intumescent materials described in the present disclosure. Examples of a commercially available intumescent material is VERSACHAR® resin, which is a thermoplastic intumescent layer available from FlameOFF Coatings, Inc., of Raleigh, N.C. In an alternative example, the fire retardant layers can comprise the intumescent material impregnated into a fiberglass fabric. In yet another example, the fire retardant layers can comprise the intumescent material without a fabric or fibers (e.g., a layer of the intumescent material alone).
Other optional layers that can be employed include intumescent layers and/or decorative layers, which can be disposed on one or both of the face sheets 130, 132 of any of the ballistic panels described herein. The intumescent layer functions to provide fire resistance to the ballistic panels. The intumescent layer comprises intumescent materials that can be, for example, organic material formulations that create a foam in the presence of heat. Example temperatures at which the intumescent materials activate to form a foam are about 250° F. to about 450° F. The foam acts as a thermal barrier against heat penetration in the event of a fire. The D3O gel will most likely not have the same flammability properties as the aramid core into which the gel is incorporated, and the intumescent materials can aid in providing a desired level of fire resistance to the panel. Examples of a commercially available intumescent material is VERSACHAR® resin, which is a thermoplastic intumescent layer available from, for example, FlameOFF Coatings, Inc. of Raleigh, N.C. or Ed Gregor and associates of South Carolina. In another embodiment, a fabric can be pre-impregnated with an intumescent polymer, such as VERSACHAR®. This would incorporate nicely into a composite stack up where one or more plies of the pre-impregnated fabric (prepreg) can be disposed on the outside surface of the ballistic laminate. The intumescent layer can have any suitable thickness. As an example, the intumescent layer has a thickness ranging from about 0.001 inch to about 0.1 inch, such as about 0.002 inch to about 0.01 inch. The decorative layers can include, for example, wall paper, paint, logos or any other desired layer applied to enhance visual appearance of the panel. Such decorative layers can optionally be applied to any of the ballistic panels described herein.
The ballistic panels of the present disclosure can be employed in any desired application for which ballistic protection is desired. Examples of such applications include bullet proofing of aircraft, aerospace and other vehicles or structures used for military purposes. Other examples include ballistic resistant door panels employed between the passenger compartment and cabins of commercial aircraft as an anti-terrorism measure, and other applications in which relatively light weight ballistic protection is desired.
An example of a ballistic resistant door 200 of an aircraft 202 is shown in
Referring to
The first layer comprising ballistic gel material and the second layer comprising ballistic gel material, as described for any of the ballistic panels above, can each be a cellular core layer manufactured by incorporating a ballistic gel into a plurality of cells formed by cell wall, as shown in
The methods described herein can optionally include attaching additional layers to the ballistic panels. For example, the methods can optionally include attaching underlying layer 136 and/or the first face sheet 130 on the first layer comprising ballistic gel material and an underlying layer 138 and/or a second face sheet 132 on the second layer comprising ballistic gel material.
Any other suitable layers described herein can also optionally be applied as part of the methods of the present disclosure. As an example, the method can optionally further include attaching one or more layers of para-aramid fibers woven into a fabric and impregnated with a fire retardant. As yet another example, the method can optionally further include applying an intumescent layer that can act as a fire retardant on the first face sheet and/or the second face sheet. As another example, the method can optionally comprise attaching a first cellular layer to the first layer of ballistic resistant material prior to attaching the first face sheet and attaching a second cellular layer to the second layer of ballistic resistant material prior to attaching the second face sheet, the first cellular layer and the second cellular layer both comprising cell walls that form a plurality of cells, the plurality of cells being filled with a gas. The first face sheet can be attached to the first cellular layer and the second face sheet can be attached to the second cellular layer, similarly as illustrated in
The optional intumescent layers and/or decorative layers can be applied to the face sheets 130, 132 by any suitable layer techniques. Suitable layer techniques are well known in the art and could be selected by one of ordinary skill in the art. A primer (not shown) can optionally be applied to the face sheet(s) prior to applying the intumescent layer. The primer aids in providing satisfactory adhesion between the intumescent layer and the face sheets.
One or more, such as all, of the layers of the ballistic panels can be adhered together using adhesive layers, as described above. For example, the method can include adhering the first layer comprising ballistic gel material 120 to the core layer 102 and adhering the second layer comprising ballistic gel material 122 to the core layer 102 using adhesive layers 150. Other adhesive layers 150 can be used to adhere the face sheets 130,132 to the ballistic panel. The adhering process can be performed by a hot bonding method, which employs heating to cure the adhesion layers 150, such as at any of the hot bonding temperatures described herein. While hot bonding methods are preferred because they save process time compared to cold process techniques, cold bonding methods can also be employed if desired. Both hot bonding and cold bonding techniques are generally well known in the art.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein.
While the present teachings have been illustrated with respect to one or more implementations, alterations and/or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In addition, while a particular feature of the present teachings may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular function.
Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” Further, in the discussion and claims herein, the term “about” indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the intended purpose described herein. Finally, “exemplary” indicates the description is used as an example, rather than implying that it is an ideal.
It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompasses by the following claims.
