Multi-layer structure for ballistic protection

Abstract

A ballistic protection is described. The ballistic protection includes a rigid structure and a flexible structure, co-operating to dissipate energy associated to an incident bullet impact, the rigid structure and the flexible structure being separated by at least a first discontinuity layer. The rigid structure includes at least a first rigid layer, at least a second rigid layer, and at least a third layer interposed between the first and the second rigid layer. The material of the first discontinuity layer and of the third layer of the rigid structure are selected so that a speed of propagation of a sound wave through the first discontinuity layer and the third layer of the rigid structure is less than 50% of the speed of propagation of a sound wave through fibers of the first rigid layer. The third layer can have a frame shape extending along the edges of the ballistic rigid protections, so that protection is increased along the borders.

1 . A ballistic protection, including at least one rigid structure and at least one flexible structure, co-operating to dissipate energy associated to an incident bullet impact, the at least one rigid structure and the at least one flexible structure being separated by at least one first discontinuity layer, the at least one rigid structure including:
 at least one first rigid layer comprising fibers;   at least one second rigid layer comprising fibers; and   at least one third layer interposed between the at least first and the at least second rigid layer;   wherein the material of the at least one third layer of the rigid structure is selected so that the speed of propagation of a sound wave through the at least one third layer of the rigid structure is less than 50% of the speed of propagation of a sound wave through the fibers of the at least one first rigid layer.   
     
     
         2 . The ballistic protection of  claim 1 , wherein the at least one first rigid layer is a textile element which includes one or more of the following: UHMW polyethylene, aramidic, copolyaramidic, polybenzoossazole, polybenzothiazole, liquid crystal, rigid rod fibers. 
     
     
         3 . The ballistic protection of  claim 2 , wherein the at least one second rigid layer is a textile element including one or more of the following: UHMW polyethylene, aramidic, copolyaramidic, polybenzoossazole, polybenzothiazole, liquid crystal, rigid rod, glass, carbon fibers. 
     
     
         4 . The ballistic protection of  claim 3 , wherein the at least one first and at least one second textile elements comprise laminate textile elements in form of: unidirectional, semi-unidirectional, bi-axial, multiaxial, or warp and weft structures. 
     
     
         5 . The ballistic protection of  claim 4 , wherein the laminate textile elements are totally or partially impregnated by one or more of the following: thermoplastic, thermosetting, elastomeric, viscous or viscoelastic polymers. 
     
     
         6 . The ballistic protection of  claim 1  wherein the at least one third layer of the rigid structure includes a first and a second part, the first part being fixed to the at least one first rigid layer and the second part being fixed to the at least one second rigid layer, the first and the second parts being reversibly detachable by means of separable fastening means. 
     
     
         7 . The ballistic protection of  claim 6 , wherein the first and the second parts are the two members of a Velcro fastening device, wherein one of the two parts is a Velcro hooks member and the other of the two parts is a Velcro loops member. 
     
     
         8 . The ballistic protection of  claim 2 , wherein the at least one third layer of the rigid structure includes material selected from the group consisting of rigid or flexible plastomeric foams, elastomeric foams, viscoelastic foams, paper, woven fabrics, non-woven fabrics, felts, honeycomb structures, elastomeric polymers, plastomeric polymers, viscous or viscoelastic polymers or mixtures thereof and having a thickness between 0.05 mm and 15 mm. 
     
     
         9 . The ballistic protection of  claim 8 , wherein the at least one third layer of the rigid structure includes a metallic element, also in form of metallic foam. 
     
     
         10 . The ballistic protection of  claim 8 , wherein the at least one third layer of the rigid structure is an element that covers only a portion of a surface corresponding to a surface of the at least one first rigid layer. 
     
     
         11 . The ballistic protection of  claim 10 , wherein the at least one third layer of the rigid structure has a shape substantially of a frame having an empty space in the middle. 
     
     
         12 . The ballistic protection of  claim 8 , wherein the at least one flexible structure includes flexible antiballistic fabrics or flexible antiballistic laminates totally or partially impregnated by one or more of the following: thermoplastic, thermosetting, elastomeric, viscous or viscoelastic polymers. 
     
     
         13 . The ballistic protection of  claim 8 , including at least one ceramic element also embedded in a polymeric structure and situated outside and before the at least one rigid structure and the at least one flexible structure with respect to the incident bullet direction. 
     
     
         14 . The ballistic protection of  claim 13 , further comprising a discontinuity layer between the at least one ceramic element and the at least one rigid structure. 
     
     
         15 . A ballistic protective article, including the ballistic protection according to  claim 1 . 
     
     
         16 . The ballistic protection of  claim 8 , wherein the at least one first discontinuity layer includes material selected from the group consisting of rigid or flexible plastomeric foams, elastomeric foams, viscoelastic foams, paper, woven fabrics, non-woven fabrics, felts, honeycomb structures, elastomeric polymers, plastomeric polymers, viscous or viscoelastic polymers or mixtures thereof and having a thickness between 0.05 mm and 15 mm. 
     
     
         17 . The ballistic protection of  claim 10 , wherein the at least one third layer of the rigid structure has a shape substantially of a frame having a space in the middle filled with material. 
     
     
         18 . A ballistic protection rigid structure, comprising:
 a first rigid textile element including one or more of the following: UHMW polyethylene, aramidic, copolyaramidic, polybenzoossazole, polybenzothiazole, liquid crystal, rigid rod fibers;   a second rigid textile element; and   a third layer interposed between the first rigid textile element and the second rigid textile element, wherein the third layer includes elements made of a material selected from the group of consisting of rigid or flexible plastomeric foams, elastomeric foams, viscoelastic foams, paper, woven fabrics, non-woven fabrics, felts, honeycomb structures, elastomeric polymers, plastomeric polymers, viscous or viscoelastic polymers or mixtures thereof;   wherein the speed of propagation of a sound wave through the third layer is less than 50% of the speed of propagation of a sound wave through the first rigid textile element.   
     
     
         19 . The ballistic protection rigid structure of  claim 18 , wherein the third layer has a thickness between 0.05 mm and 15 mm. 
     
     
         20 . The ballistic protection rigid structure of  claim 18 , wherein the second rigid textile element includes one or more of the following: UHMW polyethylene, aramidic, copolyaramidic, polybenzoossazole, polybenzothiazole, liquid crystal, rigid rod, glass, carbon fibers.