Heat-hardening prepregs

A cheaper alternative is the cold temperature hardening prepreg system. As opposed to heat-hardening prepregs, where the prepreg fabrication can take place at a different place and time than the manufacture of the ultimate component, in the cold temperature process the fabric or rovings are coated with the matrix at the point where the component itself is made. 

Composite materials are typically made using the above-mentioned fibers and fabrics, or other types, as well as a matrix material. A resin, such as epoxy, is used to impregnate the fabric and then the composite is heated to cure and harden. Sometimes pressure is applied to form the composite into a specific shape with exact target dimensions. In the case of unidirectional or fabric prepregs, the layers are stacked and then heated under pressure to form the composite. 

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