Thermoplastic prepreg lines make use of a polymer system that has reoccurring plasticity with heat. The polymer can be heated and reheated multiple times, and typically flows as a liquid when hot. The use of thermoplastics in composites is less wide-spread than thermoset polymers & resins. Thermoplastics are seen as a lower cost, higher production rate alternative to the traditional thermoset prepregs, particularly given that thermoset prepregs, β-stage materials, have a limited shelf life, require temperature-controlled storage, and contain hazardous/noxious materials.