Projectile-stopping composite material - contg. steel plates, polyamide 12 layers and aramid fibre layers

摘要

In parent patent projectile-stopping composite material contains a steel plate coated on one or both sides with polyamide 12 (obtd. by anionic polymerisation with use of monomeric lauric lactam). In this addn. the effectiveness of this material is enhanced by applying onto the free side of the polyamide 12 layer several layers of aramid fibre web ('Kevlar'; RTM), topped by another polyamide 12 layer. Opt. several layers of aramid fibres (pref. 5-15 webs in each layer) and several polyamide 12 layers can be applied in alternating order. The aramid fibre webs are pref. impregnated and/or densely woven. One or two hard steel plates can be used. Polyamide 12 and aramid fibres have high resistance against deformation. Therefore, they effectively brake the projectile and convert its energy into heat which is absorbed by the polymers when they eventually melt. The combination of polyamide 12 and aramid fibres gives a synergistic effect. Polyamide 12 dams the mechanical vibrations produced by the impact of a projectile.