Prepregs are reinforcing fibres that are already pre-impregnated with resin. The most common are the so-called "fabric prepregs", although tapes and unidirectional and multiaxial sheets are also more than suitable for prepregnation. Modified epoxy and phenol resins, which do not become fluid at room temperature, are used as the resin matrix. The prepreg is normally inserted cold into a mould and fully cured under pressure and at a given temperature. Upon heating, the resin liquefies very quickly for a short time and permeates the fibres completely, before it then starts to harden. HexPly® prepregs offer the right solution for a variety of applications.