Enhanced energy absorbing materials
Dense, highly stable, high performance ballistic material comprises at least one woven layer of ballistic grade fiber (preferably a stack of such layers) and at least one nonwoven layer of fabric which is entangled with the woven or unidirectional layer by needle felting. The resulting core material does not require assembly of individual woven layers during subsequent manufacture of ballistic articles and exhibits excellent ballistic performance at low areal densities and thicknesses.
1. A ballistic material comprising a stack of woven layers, and at least one nonwoven batting layer on a face of said stack of woven layers, said nonwoven layer attached to and entangled with the stack of woven layers by needlepunching to form an integral material having an areal weight of about 0.07 pounds per square foot (342 g/m 2 ) to about 10 pounds per square foot (48.8 kg/m 2 ).
2. The ballistic material of claim 1 , comprising a non woven layer on each face of said stack of woven layers.
3. The ballistic material of claim 1 , wherein the stack of woven layers comprises 4 to 20 quasi-unidirectional aramid fiber fabric layers cross laid at right angles.
4. The ballistic material of claim 1 , wherein the nonwoven layer consists essentially of fibers having a tenacity of at least about 15 grams per denier (13.5 g/decitex) and a tensile modulus of at least about 400 grams per denier (360 g/decitex).
5. The ballistic material of claim 1 , having a backface signature of less than 44 mm at a material areal density of 0.5 pounds per square foot (2.44 kg/m 2 ).
6. The ballistic material of claim 1 , calendered to a thickness of about 0.1 inches (0.254 cm) to about 0.3 inches (0.76 cm) having an areal density of 0.18 pounds per square foot (878 g/m 2 ) to about 0.60 pounds per square foot (2.928 kg/m 2 ).
7. A ballistic material comprising at least one woven layer of ballistic grade fiber and at least one nonwoven fiber layer of batting, said nonwoven batting layer entangled with the woven or unidirectional layer in a direction substantially perpendicular to an x-y plane of the ballistic material.
8. The material of claim 7 , wherein said nonwoven layer is entangled with the woven layer by needlepunching.
9. The material of claim 7 , wherein said woven layer comprises unidirectional or quasi-unidirectional ballistic grade fibers.
10. The material of claim 7 , wherein said at least one nonwoven layer comprises ballistic grade fibers.
11. The material of claim 7 , wherein said at least one nonwoven layer comprises staple para-aramid fibers.
12. The material of claim 7 , comprising a plurality of layers of unidirectional tows of ballistic grade fibers cross-laid at 90 degree angles.
13. The material of claim 7 , comprising a plurality of layers of woven ballistic grade fabric.
14. The material of claim 7 , comprising a plurality of layers of knitted ballistic grade fabric.
15. The material of claim 7 , comprising a plurality of layers of stitched tows of ballistic grade fibers.
16. The material of claim 7 , further comprising a water repellent coating.
17. The material of claim 7 , having a thickness reduced by calendering.