A Prepreg is an industry term used for a reinforcing fabric, such as carbon fiber or fiberglass, that has been pre-impregnated with a resin system. The resin system used to impregnate the material contains the proper resin and hardener mixture to facilitate curing - making prepregs ready to layup without additional resin work required.
Generally, prepregs are used by fabricators to produce parts requiring lightweight, consistent, high-quality result thought-out various industries including aerospace, medical, space, automotive, racing, sporting goods and more.
Thermoplastic prepregs are composite reinforcements (fiberglass, carbon fiber, etc.) that are pre-impregnated with thermoplastic resin. Common resins for thermoplastic prepregs include PP, PET, PE, PPS, and PEEK. Thermoplastic prepregs can be provided in unidirectional tape, or in fabrics that are woven or stitched.
More commonly used in prepreg composite manufacturing is thermoset prepregs. The primary resin matrix used is epoxy. Other thermoset resins are made into prepregs including BMI and phenolic resins.
With a thermoset prepreg, the thermosetting resin starts as a liquid and fully impregnates the fiber reinforcement. Excess resin is precisely removed from the reinforcement. Meanwhile, the epoxy resin undergoes partial curing, changing the state of the resin from a liquid to a solid. This is known as the "B-stage."
Maximum strength characteristic. A typical manual ply has a lot of excess resin, which increases Brittleness and reduces overall
Performance. Most prepregs contain about 35% resin, which is ideal for achieving maximum curing performance, which is usually not
possible with conventional manual lamination.
Uniformity and repeatability. The prepreg is of uniform thickness and each part coming out of the mold may theoretically be the same. Vacuum bagging technology still has some errors in processing, but prepreg can greatly reduce these problems.
Reduce curing time.After the thermal curing cycle, no need to wait for the standard 48 hours can be fully cured.
Looks better.Although prepreg processing still requires mold preparation and demoulding, prepreg processing eliminates air bubbles and makes it easier to obtain a smooth, glossy surface.
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