The invention describes a composite material comprising a substrate having, on at least one of its faces, an impact-resistant primer layer and at least one abrasion-resistant coating layer deposited on the primer layer. The invention is characterised in that it includes a step for polymerising at least one vinylaromatic monomer in the presence of rubber, a polymerisation initiator and a stable free radical, said step being such that FSFR: FAMO range from 0. A short curved blade edge is formed between the radius arc vertex and the radius arc vertex of the cutting edge.