Sheets of a substrate that have been impregnated with a curable polymer, curable polymers, or liquid reactants, or a thermoplastic, and are ready for fabrication of laminates.
Note:
During the impregnation, the curable polymer, curable polymers, or liquid reactants may be allowed to react to a certain extent (sometimes termed degree of ripening).
Source:
PAC, 2004, 76, 1985. 'Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004)' on page 1991 (https://doi.org/10.1351/pac200476111985)