The key difference between Prepreg and Core is their state of resin curing and primary function: Core is a fully cured, rigid structural substrate clad with copper, while Prepreg is a flexible, partially cured material used as an adhesive to bind layers together during lamination. Direct Comparison Feature Core Material Prepreg (Pre-impregnated) Resin State C-stage (Fully cured): Solid, rigid, and thermally stable. B-stage (Partially cured): Soft, pliable resin that melts under heat and pressure. Copper Cladding Comes pre-laminated with copper foil on one or both sides. Comes without copper (pure fiberglass weave soaked in resin). Primary Function Provides main mechanical rigidity and internal base layers. Acts as glue/insulation to bond Cores and outer copper foils. Rigidity Stiff and rigid prior to lamination. Flexible and pliable until heat-cured during lamination. Thickness Control Fixed, precise factory thickness. Thickness compresses slightly when melted under press. ...
