Ballistic resistant body armor articles

Abstract

The present invention relates to body armor articles for resisting ballistic objects. The articles comprise unidirectional fabric layers and sheet layers. The unidirectional fabric layers are made from yarns having a tenacity of at least 7.3 grams per dtex and a modulus of at least 100 grams per dtex. The sheet layers comprise non-woven random oriented fibrous sheets and/or non-fibrous films. The unidirectional fabric layers and the sheet layers are stacked together comprising a first core section which includes at least two repeating units of, in order, at least one of the unidirectional fabric layers then at least one of the sheet layers. The sheet layers comprise 0.5 to 30 wt % of the total weight of the article.

What is claimed is: 
     
         1 . A body armor article for resisting ballistic objects, comprising: a plurality of unidirectional fabric layers made from yarns having a tenacity of at least 7.3 grams per dtex and a modulus of at least 100 grams per dtex; a plurality of sheet layers comprising non-woven random oriented fibrous sheets and/or non-fibrous films, each of the sheet layers having a thickness of at least 0.013 mm; the unidirectional fabric layers and the sheet layers stacked together comprising a first core section which includes at least two repeating units of, in order, at least one of the unidirectional fabric layers then at least one of the sheet layers; wherein
 (i) the sheet layers comprise 0.5 to 30 wt % of the total weight of the article,   (ii) each of the sheet layers has an average acoustic velocity of at least 600 m/sec,   (iii) the sheet layers are isotropic or substantially isotropic for average acoustic velocity, and   (iv) the unidirectional fabric layers and the sheet layers are attached together at 10% or less of their surface areas.   
     
     
         2 . The article of  claim 1 , wherein the yarns have linear density of 50 to 4500 dtex, a tenacity of 10 to 65 g/dtex, a modulus of 150 to 2700 g/dtex, and an elongation to break of 1 to 8 percent. 
     
     
         3 . The article of  claim 1 , wherein the yarns are made of filaments made from a polymer selected from the group consisting of polyamides, polyolefins, polyazoles, and mixtures thereof. 
     
     
         4 . The article of  claim 1 , wherein each of the sheet layers have a thickness of no more than 0.152 mm. 
     
     
         5 . The article of  claim 1 , wherein the sheet layers are made of materials selected from the group consisting of polycondensation products of dicarboxylic acids with dihydroxyalcohols, ionomers, thermoplastic fluoropolymers, polyolefins, polyimides, aramid, glass, ceramic, carbon and mixtures thereof. 
     
     
         6 . The article of  claim 1 , wherein each of the sheet layers has a ratio of maximum strain to failure value to minimum strain to failure value of 1 to 5. 
     
     
         7 . The article of  claim 1 , wherein the core section includes 3 to 60 of the unidirectional fabric layers and 3 to 60 of the sheet layers. 
     
     
         8 . The article of  claim 1 , wherein there are 3 to 50 of the repeating units. 
     
     
         9 . The article of  claim 1 , wherein the core section has a first strike end surface and a body facing end surface; and the article further comprising a first strike section and a body facing section, the first strike section comprising a plurality of the unidirectional fabric layers stacked together and stacked on the first strike end surface of the core section, and the body facing section comprising a plurality of the unidirectional fabric layers stacked together and stacked on the body facing surface of the core section. 
     
     
         10 . The article of  claim 1 , wherein the core section has a unidirectional fabric end surface and a sheet end surface, further comprising at least one of the unidirectional fabric layers stacked on the sheet end surface of the core section. 
     
     
         11 . The article of  claim 1 , wherein the core section comprises a plurality of core subsections, each core subsection with a repeating unit. 
     
     
         12 . The article of  claim 1 , wherein the unidirectional fabric layers and the sheet layers are only attached together at 10% or less of their surface areas allowing all or most of the remainder of the layers to move laterally and/or separate with respect to adjacent layers. 
     
     
         13 . The article of  claim 1 , wherein the unidirectional fabric layers and the sheet layers, stacked together, have an areal density of 2.5 to 5.7 kg/m 2 . 
     
     
         14 . The article of  claim 9 , wherein the first strike section has 2 to 30 unidirectional fabric layers stacked together and the body facing section has 2 to 30 unidirectional fabric layers stacked together.