Prepregs are fibre reinforcements (usually fabric) which are already preimpregnated with resin. As matrix especially modified epoxy resins (optionally phenolic resins) are used, which do not flow at room temperature.
A prepreg is therefore leathery and slightly tacky on the surface. Special paper sheets prevent sticking on the roll.
Prepregs can be cut precisely and cleanly without distortion and fibre abrasion. Cut pieces are inserted cold into the mould. The protective paper is removed so that the layers adhere to each other.
The resin liquefies for a short time under pressure (in the tool or vacuum) and temperature, the prepreg stack becomes soft and displaceable, so that complicated shaping is also possible. The resin cures after a short time.
- bubble-free laminates with high fibre content
- very light and high-strength components with high heat resistance
- complex and large components
- optically very good surfaces