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.
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).
PAC, 2004, 76, 1985
(Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004))
on page 1991
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook