Abstract:
In an aspect, the invention features a ballistic-resistant panel including at least one layer of ballistic material having a phase change material disposed thereon and an outer cover having inner surface that forms a pocket and an outer surface having an inner face and an outer face. The ballistic material has an inner surface and an outer surface and is disposed within the pocket of the outer cover with the ballistic material inner surface adjacent to the outer cover inner face.

Description:
FILED OF INVENTION  
       [0001]     The present invention relates to ballistic materials, and more specifically temperature regulating ballistic materials.  
       BACKGROUND  
       [0002]     Conventional bullet-resistant garments, such as bullet-resistant vests, tend to cause the user to become hot, perspire and potentially overheat, especially during strenuous activities or hot days. Most bullet-resistant garments are designed to be worn by law enforcement or military personnel, who are often involved in strenuous activities, such as foot pursuits, patrolling or being involved in a firefight. However, because the bullet-resistant garments are often too hot, many users do not regularly wear the protective garment, thereby increasing the risk of injury due to ballistic threats (e.g., bullets or shrapnel). The present invention helps overcomes these limitations.  
       SUMMARY  
       [0003]     The present invention provides ballistic materials that include phase change materials to help regulate the body temperature of a wearer of garments including ballistic material. The phase change material disposed on the ballistic material regulates the temperature of the wearer by absorbing heat from the wearer when the wearer is hot and giving the heat back to the wearer when the wearer cools down.  
         [0004]     In general, in one aspect, the invention features a ballistic-resistant panel having at least one layer of ballistic material with a ballistic material inner surface and a ballistic material outer surface, a phase change material disposed on the ballistic material, and an outer cover. The outer cover has an outer cover inner surface and an outer cover outer surface, where the inner surface forms a pocket, and an inner face and an outer face, where the inner face is adjacent to a user when worn. The ballistic material is disposed within the pocket of the outer cover with the ballistic material inner surface adjacent to the outer cover inner face.  
         [0005]     In embodiments, each layer of ballistic material comprises more than one ballistic ply to each other. In certain embodiments, each of the ballistic plies include phase change material disposed thereon. In other embodiments, less than all of the ballistic plies include phase change material disposed thereon. In embodiments, less than all of the ballistic plies include phase change material disposed thereon and the phase change material is disposed on the ballistic plies closest to the ballistic material inner surface.  
         [0006]     In embodiments, all layers of ballistic material include phase change material disposed thereon. In other embodiments, less than all layers of ballistic material include phase change material disposed thereon. In embodiments, the ballistic material may be aramid, para-aramid, polypropylene, polyethylene, poly (p-phenylene-2,6-benzobisoxazole), polyester, nylon, liquid crystal polymers or any combination thereof.  
         [0007]     In embodiments, the ballistic-resistant panel includes a first layer of ballistic material made of a first ballistic material adjacent to the outer cover inner face, the first layer having at least one ply, and a second layer of ballistic material made of a second ballistic material adjacent to the outer cover outer face, the second layer having at least one ply, the two layers being adjacent to each other. In certain embodiments, the phase change material is disposed on the first layer. In embodiments, the first layer is woven plies, the second layer is non-woven plies, and the phase change material is disposed on the second layer of non-woven plies. In embodiments, the first layer and second layer are mechanically connected by portions of the non-woven plies which extend into the woven plies, perpendicular to the woven plies.  
         [0008]     In embodiments, the ballistic-resistant panel also includes a first layer of ballistic material made of a first ballistic material adjacent to the outer cover inner face, the first layer having at least one ply, a second layer of ballistic material made of a second ballistic material adjacent to the outer cover outer face, the second layer having at least one ply, and a third layer of ballistic material made of a third ballistic material, the third layer having at least one ply, where the third layer is disposed between the first and second layers. In certain embodiments, the first ballistic material and the second ballistic material are the same ballistic material. In embodiments, the first ballistic material, second ballistic material and third ballistic material may be aramid, para-aramid, polypropylene, polyethylene, poly (p-phenylene-2,6-benzobisoxazole), polyester, nylon, liquid crystal polymers or any combination thereof.  
         [0009]     In embodiments, the first layer and second layer are woven plies, the third layer is non-woven plies, and the phase change material is disposed on the third layer of non-woven plies. In embodiments, the first layer and third layer are mechanically connected by portions of the non-woven plies which extend into the woven plies perpendicular to the woven plies.  
         [0010]     In embodiments, the phase change material may be paraffin compounds, such as paraffinic hydrocarbons, salt hydrides, fatty acids, esters, inorganic salts, or eutectic compounds. In embodiments, the outer cover also includes phase change material.  
         [0011]     In general, in another aspect, the invention features a bullet-resistant garment including an armor carrier having a contact surface, which is adjacent to a user when worn, and a retaining compartment and a ballistic panel disposed within the retaining compartment. The ballistic panel includes a first layer of ballistic material made of multiple plies of a first ballistic material, a second layer of ballistic material made of multiple plies of a second ballistic material, a third layer of ballistic material made of multiple plies of a third ballistic material, where the third layer is disposed between the first and second layers forming a ballistic unit, a phase change material disposed on at least one layer of ballistic material, and an outer cover including an outer cover inner surface and an outer cover outer surface, the inner surface forming a pocket, the cover also including an inner face and an outer face. The ballistic unit is disposed within the pocket of the outer cover with the first layer adjacent to the outer cover inner face and the second layer adjacent to the outer cover outer face. The outer cover inner face is adjacent to the contact surface when disposed in the retaining pocket of the armor carrier.  
         [0012]     In embodiments, the phase change material may be paraffin compounds, such as paraffinic hydrocarbons, salt hydrides, fatty acids, esters, inorganic salts, or eutectic compounds. In embodiments, the first ballistic material, second ballistic material and third ballistic material may be aramid, para-aramid, polypropylene, polyethylene, poly (p-phenylene-2,6-benzobisoxazole), polyester, nylon, liquid crystal polymers or any combination thereof.  
         [0013]     In embodiments, the first ballistic material and second ballistic material are the same. In other embodiments, the first ballistic material and second ballistic material are woven fabrics and the third ballistic material is a non-woven material with the phase change material disposed thereon, whereby at least the first layer of ballistic material and third layer of ballistic material are mechanically connected by portions of the non-woven third layer which extend into the first layer perpendicular to the woven fabric.  
         [0014]     In embodiments, the outer covering also includes phase change material. In certain embodiments, the contact surface of the armor carrier also has a wicking material and a vapor barrier between the wicking material and the outer cover of the ballistic panel. In other embodiments, the contact surface of the armor carrier includes a wicking material and the outer cover of the ballistic panel includes a vapor barrier. In embodiments, the outer cover also includes an inner layer having phase change material.  
         [0015]     In general, in another aspect, the invention features a method for making a ballistic panel including stacking multiple plies of a first ballistic material together to make a first layer, stacking multiple plies of a second ballistic material together to make a second layer, and stacking multiple plies of a third ballistic material together to form a third layer. The first layer, second layer and third layers are stacked adjacent to each other with the third layer disposed between the first and second layers to make a ballistic unit. A phase change material is disposed on at least one layer of the ballistic material. The ballistic unit is placed within a pocket formed in an outer cover, the outer cover having an outer cover inner face and outer cover outer face, the first layer being adjacent to the outer cover inner face and the second layer being adjacent to the outer cover outer face.  
         [0016]     In embodiments, disposing the phase change material on the ballistic material is performed while the ballistic material is being made. In other embodiments, disposing the phase change material on the ballistic material is performed prior to the plies being cut. In other embodiments, disposing the phase change material on the ballistic material is performed after the plies are cut. In still other embodiments, disposing the phase change material on the ballistic material is performed after the layers are formed. In other embodiments, disposing the phase change material on the ballistic material is performed after the layers are stacked.  
         [0017]     In embodiments, the phase change material may be paraffin compounds, such as paraffinic hydrocarbons, salt hydrides, fatty acids, esters, inorganic salts, or eutectic compounds. In embodiments, the first ballistic material, second ballistic material and third ballistic material may be aramid, para-aramid, polypropylene, polyethylene, poly (p-phenylene-2,6-benzobisoxazole), polyester, nylon, liquid crystal polymers or any combination thereof. In embodiments, the first ballistic material and second ballistic material are the same.  
         [0018]     In embodiments, the first ballistic material and second ballistic material are woven fabrics, the third ballistic material is a non-woven material, and the phase change material is disposed on the non-woven material. The first layer and third layer are mechanically connected by needle felting the ballistic unit, thereby pulling portions of the non-woven third layer into the woven first layer perpendicular to the woven fabric and entangling the two layers.  
         [0019]     The invention can be implemented to realize one or more of the following advantages. Incorporating phase change materials directly into the ballistic fabric eliminates the need to include bulky insert cooling packs, which are often fitted into pockets within the bullet-resistant garment. This enables the entire ballistic garment to become a temperature regulating device, thereby eliminating smaller cooling spots concentrated only at the places where pockets can be added to the garment. Further, the phase change materials within the ballistic fabric allows for a thinner and lighter garment, thereby resulting in a more comfortable garment to wear. Also, the cooling effect of the ballistic panel can be made to be closer to the user&#39;s body, thereby increasing the cooling effect. Further still, the use of phase change materials enables the heat generated by the user to be transferred back to the user after the strenuous activity ends and the user&#39;s body temperature starts to cool.  
         [0020]     Other features and advantages of the invention are apparent from the following description, and from the claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is a partial cut-away view of an exemplary ballistic panel according to one embodiment of the invention.  
         [0022]      FIG. 2  is a cross-section of the ballistic panel of  FIG. 1 .  
         [0023]      FIG. 3  is a partial cut-away perspective view of an exemplary armor carrier containing the ballistic panel of  FIG. 1 . 
     
    
       [0024]     Like reference numbers and designations in the various drawings indicate like elements.  
       DETAILED DESCRIPTION  
       [0025]     Referring to  FIGS. 1 and 2 , a ballistic panel  10  includes an outer covering  12 . The outer covering  12  has an inner face  14  positioned towards a user, and usually in contact with the user, when worn and an outer face  16  positioned away from the user when worn. The outer covering  12  is configured to contain ballistic material and may be made from any suitable material.  
         [0026]     The ballistic material may include several layers of varying material. For example, the ballistic material may include plies  18 A and  26 A made from a first material and plies  22 A made from a second material. For example, the first material may be aramid and the second material may be polyethylene (or vice versa), but any suitable ballistic material may be used. The plies  18 A,  22 A and  26 A are grouped into layers  18 ,  22  and  26  and laid adjacent to each other to form a ballistic unit  27 . Depending on the desired amount of protection to be supplied by the ballistic panel  10 , different numbers of plies  18 A,  22 A and  26 A are used to form the ballistic unit  27 . Each layer  18 ,  22  and  26  has an inner surface  20 ,  24  and  28  respectively that is positioned towards the user when worn.  
         [0027]     To improve thermal comfort of a ballistic garment, the ballistic unit  27  includes a phase change material. Phase change materials referred to herein are substances that change phase (i.e., solid to liquid or liquid to solid) within a temperature range around average skin temperature. An exemplary phase change material would tend to stabilize into a slush state of half liquid and half solid just below a comfortable skin temperature at rest. Then, as an activity level of the user increases, the slush absorbs the excess heat generated by the user, keeping the body cooler and extending the time before the user begins to perspire. For example, if a law enforcement officer wearing a bullet-resistant vest containing phase change material is chasing a suspect on foot on a cold winter day, the strenuous activity of running would cause the officer&#39;s skin temperature to rise. The phase change material within the bullet-resistant vest absorbs the heat and shifts towards a liquid, rather than reflecting the heat back towards the skin, helping the officer maintain a more comfortable body temperature and not overheat. After the officer stopped running and was standing in the cold surrounding temperature, the phase change material returns the heat to the officer, and returns towards a solid, so that the officer does not become cold. The phase change material acts as a thermal shock absorber by slowing or minimizing the rate of temperature change within the user&#39;s clothing or microclimate. By applying phase change materials to the ballistic material, the ballistic panel  10  becomes a temperature regulating device.  
         [0028]     The phase change material can be infused into the ballistic material in several ways. In one example, layer  18  is made from para-aramid fibers, such as Kevlar® from DuPont, that is infused with a micro-encapsulated phase change material, such as paraffin compounds sold by Outlast Technologies, Inc., of Boulder, Col., under the trade name Thermocules®. In other examples, the phase change material may be bulk, micro-encapsulated or macro-encapsulated. In still other examples, the phase change material may be paraffin compounds, such as paraffinic hydrocarbons, salt hydrides, fatty acids, esters, inorganic salts, or eutectic compounds. Phase change materials may be bonded to the aramid fibers during the manufacturing of the aramid fibers on a nanotechnology scale. The aramid fibers are then used to weave a ballistic fabric from which ply  18 A is cut and incorporated into layer  18  of the ballistic panel  10 . Preferably, each ply  18 A of the layer  18  contains the phase change material. However, the layer  18  may be made with only certain plies  18 A containing the phase change material. Since phase change materials tend to give the best cooling effect when located close to the skin, preferably the plies closest to inner face  20  contain the phase change material.  
         [0029]     In another example of the ballistic panel  10 , layer  22  includes non-woven plies  22 A of ballistic material. The non-woven plies  22 A may be aramid fibers, para-aramid fibers (e.g., Kevlar®, Artec® or Rusar®), polyethylene fibers, polypropylene fibers, poly (p-phenylene-2,6-benzobisoxazole) (“PBO”) fibers, polyester fibers, nylon fibers, liquid crystal polymer fibers or any other ballistic resistant material. Layers  18  and  26  may include plies  18 A and  26 A made of woven fabrics, such as para-aramid fibers (Kevlar®), PBO, high molecular weight polyethylene fibers or any woven ballistic resistant material. The phase change material is applied to the non-woven ballistic layer  22 , either during the manufacture of the fibers or after the fibers are laid together to form the non-woven plies  22 A.  
         [0030]     The desired number of woven plies  18 A and  26 A and non-woven plies  22 A are laid adjacent to each other to form layers  18 ,  22  and  26 , with the non-woven layer  22  sandwiched between the woven layers  18  and  26 , to form the ballistic unit  27 . After the ballistic unit  27  is formed, the ballistic unit  27  is subjected to a needle felting process whereby needles are driven perpendicularly through the layers  18 ,  22  and  26  and catch on the non-woven fibers. As the needles are withdrawn, they pull the phase change infused non-woven fibers into and through the woven plies  18 A and  26 A. Since the phase change material tends to give the best cooling effect when located close to the skin, the non-woven fibers are preferably pulled through woven layer  18  towards inner surface  20 . The needle felting process entangles the non-woven fibers into the woven layers substantially perpendicular to the x-y plane, which mechanically connects the various plies  18 A and helps prevent the individual yams from separating during a ballistic impact. The needle felting processes also increases the density of the ballistic unit  27  by engaging more fibers per unit volume. Also, by needling a felt towards inner surface  20 , the phase change material is brought closer to the user&#39;s body, providing a better cooling effect. By selectively needling a felt towards particular areas of the ballistic panel, it is possible to optimize cooling in areas that tend to overheat first, such as under a user&#39;s arms during strenuous activity or the lower back when seated in a vehicle on a hot day.  
         [0031]     Referring to  FIG. 3 , the ballistic panel  10  is placed within a retaining compartment  31  in an armor carrier  30  through opening  38 . The opening can be closed with a zipper, snaps, hook and loop fasteners or any other suitable fastener. The armor carrier  30  has a contact surface  32  which is adjacent to the user when worn and an outer surface  34  which faces away from the user. To enhance the temperature regulating effect of the phase change material within the ballistic panel  10 , armor carrier  30  may include a moisture wicking material, either as a fabric within the armor carrier  30  or as a coating applied to the armor carrier  30  on at least the contact surface  32 . Such moisture wicking material may enable enhanced cooling through evaporation by pulling perspiration away from the user. When a moisture wicking material is included within the armor carrier  30 , a vapor barrier is recommended between the armor carrier  30  and the ballistic panel  10 . The vapor barrier can be an additional layer  36  in the armor carrier  30  or the outer covering  12  of the ballistic panel  10 .  
         [0032]     It is to be understood that the foregoing description is intended to illustrate and not to limit the scope of the invention, which is defined by the scope of the appended claims. Other embodiments are within the scope of the following claims. For example, while the ballistic fibers disclosed above were described as being manufactured with phase change materials, the phase change material can be applied to the ballistic fibers at a secondary stage (i.e., applied to the spool of ballistic fibers before weaving into a ballistic fabric) or to the woven fabric before it is cut to size for the plies. Further, the phase change material can be applied to an individual ballistic ply or group of plies after being woven and cut. This may be accomplished by spraying the phase change material onto the individual plies, a layer of multiple plies or the ballistic unit before placing them into the outer covering  20 , or dipping the individual plies, layers of multiple plies or the ballistic unit into phase change material before placing them into the outer covering  20 .  
         [0033]     Also, while the phase change material has been described as being on or within certain layers  18 ,  22  and  26  or various plies  18 A,  22 A and  26 A within each layer, any and/or all the layers may contain phase change material. Further, the outer covering  12  may also include phase change materials. Further still, all layers and the outer covering (i.e, the entire ballistic panel  10  and outer covering  12 ) may contain phase change materials. Also, the outer cover  12  of the ballistic panel  10  may be made of two layers of material, an outer layer made of a material that acts as a vapor barrier and an inner layer that may contain a phase change material  
         [0034]     Further, while the ballistic layers  18 ,  22  and  26  were described as being made from two different ballistic materials, each layer may be made from the same material or each layer may be made from different material (e.g., three layers using three different materials). Further still, the ballistic unit  27  could be made from more or less layers than described above (e.g., more than three layers), and each layer may be made from any suitable ballistic material.  
         [0035]     Also, while the phase change material was described in a first example as being infused into the ballistic material, in another example the phase change material may be impregnated into a plastic film, such as polyethylene. The plastic film is then disposed on a ballistic layer  18 , 22  and/or  26  or the outer cover  12  by laminating the plastic film thereto. For example, a phase change impregnated plastic film may be disposed on layer  18  by laminating the plastic film to layer  18 . Further, the phase change impregnated plastic film may be laminated between layers  18  and  22 , thereby bonding the layers together.  
         [0036]     While armor carrier  30  is shown as a vest, any configuration can be used, such as a shirt, pants or area-specific armor (head, arms, legs, knees, crotch, etc.).