Transparent composite having a laminated structure
Novel transparent composites have been developed that have relatively lower areal densities of conventional transparent composites, where the composites are tested for the same threat levels as specified in the NIT or STANAG standards. Particular transparent composites can withstand projectiles having relatively high kinetic energy, for example, using STANAG 4 testing conditions. Further, the novel transparent composites can withstand multiple hits using Multiple Hit Testing at a STANAG 2 threat level.
1. A transparent composite comprising:
a first inorganic layer;
a second inorganic layer; and
a first polymer layer having a thickness of at least 5 mm, wherein the first polymer layer comprises a polyurea,
wherein the first inorganic layer is a transparent ceramic layer,
wherein a strike face of the transparent composite is closest to the first inorganic layer as compared to each of the second inorganic layer and the first polymer layer;
wherein the second inorganic layer is disposed between the first inorganic layer and the first polymer layers.
2. The transparent composite of claim 1 , wherein the first polymer layer comprises an elastomer.
3. The transparent composite of claim 1 , further comprising:
a third inorganic layer disposed between the first inorganic layer and the second inorganic layer, wherein the third inorganic layer is a transparent ceramic layer or a glass layer;
a fourth inorganic layer disposed between the second inorganic layer and the first polymer layer, wherein the fourth inorganic layer is a glass layer; and
a second polymer layer disposed between the first polymer layer and a backing layer.
4. The transparent composite of claim 3 , wherein the second polymer layer comprises a polyurethane.
5. The transparent composite of claim 1 , wherein the transparent composite has an areal density of at most 145 kg/m 2 .
6. The transparent composite of claim 1 , wherein the transparent composite has an areal density of at most 135 kg/m 2 .
7. The transparent composite of claim 1 , wherein the transparent composite has an areal density of at most 65 kg/m 2 .
8. The transparent composite of claim 1 , wherein the transparent composite has an areal density of at most 50 kg/m 2 .
9. The transparent composite of claim 1 , wherein the transparent composite has an average thickness of at most 80 mm.
10. The transparent composite of claim 1 , wherein the transparent composite has an average thickness of at most 70 mm.
11. The transparent composite of claim 1 , wherein the first inorganic layer comprises sapphire, an aluminum oxynitride, or a magnesium aluminate.
12. The transparent composite of claim 1 , wherein the first polymer layer comprises a co-polymer formed from an isocyanate, a polyol, and an amine.
13. The transparent composite of claim 1 , further comprising a second polymer layer disposed between the first polymer layer and a backing layer.