Application of wool in high-velocity ballistic protective fabrics

The protective power of typical aramid-based ballistic fabrics, when assembled into multi-layered panels designed to defeat high-velocity ballistic impacts, can be improved if wool is incorporated into the weave structure. Although the synthetic is still the primary energy-absorbent material, the wool plays a complementary role by increasing resistive interactions between the yarns and filaments. Wool restricts the lateral separation of the synthetic yarns and ensures that more directly impacted yarns are held in place to dissipate the impact energy. Wool increases the energy-absorption mechanism of yarn pull-in by increasing the longitudinal friction along the yarns/filaments, in particular near the free edges of the fabric layers. The wool absorbs water that may otherwise lubricate synthetic filaments and so improves the wet performance. Ballistics tests have shown that synthetic fabrics blended with wool can at least match the dry or wet ballistic performance of an equivalent pure Kevlar fabric when tested under National Institute of Justice (NIJ) Ballistic Standard Level III A. The inclusion of the wool can significantly improve the tear strength of pure synthetic ballistic fabrics.