PrepregLaminate

Prepreg laminate refers to a laminated composite material composed of reinforcing fibers pre-impregnated with a resin matrix. The prepreg material is laid up in layers and cured under heat and pressure to form a solid laminate. Resin systems are typically thermosets, most commonly epoxy, but cyanate ester and bismaleimide systems are used; thermoplastic prepregs also exist but are less common.

Reinforcements include carbon fiber, glass fiber, and aramid. Prepregs can be in the form of unidirectional tapes, woven fabrics, or multi-axial fabrics, with plies cut and oriented to achieve desired stiffness and strength.

Manufacturing involves cutting or laying prepregs onto a mold or mandrel, stacking plies to the target thickness, and consolidating them with tooling and vacuum or pressure. Cure occurs by applying heat and pressure, usually in an autoclave or in out-of-autoclave equipment. Cure cycles depend on resin chemistry and laminate thickness. Some prepregs are B-staged to improve drape and preforming.

Properties and performance include high specific strength and stiffness, good fatigue resistance, and excellent environmental stability when properly cured. Prepregs enable precise resin content and fiber distribution, but require careful handling, refrigerated or frozen storage, and have limited shelf life.

Applications are concentrated in aerospace and defense, but also include high-performance sporting goods, wind turbine blades, automotive composites, and marine structures. Limitations include high material and processing costs, tooling requirements, and recycling challenges. Ongoing developments aim at longer shelf life, lower processing temperatures, out-of-autoclave cures, and recyclable resin systems.