Method for impregnating reinforcing fibres with polyaryletherketones and semi-products obtained therefrom

A process for the preparation of a semifinished product comprising a poly(aryl ether ketone) (PAEK)-based resin and reinforcing fibers, comprising the stages of:

• a. preparation of a dispersion comprising the PAEK-based resin in pulverulent form dispersed in an aqueous phase comprising at least one surfactant and, if an additive is present, only additives selected from the group consisting of antifoaming agents and biocidal agents;
• b. bringing the reinforcing fibers into contact with said aqueous dispersion;
• c. drying the fibers impregnated with dispersion;
• and
• d. heating the impregnated fibers to a temperature sufficient for the melting of the resin, so as to form a semifinished product,
• wherein the surfactant is a thermally stable surfactant which does not increase the weight-average molecular weight of the PAEK-based resin, as measured by size exclusion chromatographic analysis, by more than 20% after the heating stage.