Fibrous material impregnated with reactive thermoplastic prepolymer

An impregnated fibrous material comprising a fibrous material made of continuous fibers and at least one reactive thermoplastic prepolymer in a solid state,

• wherein said at least one reactive thermoplastic prepolymer is partially polymerized without a chain extender and has a number-average molecular weight Mn from 500 to 10,000, the proportion of fibers in said impregnated fibrous material being 45 to 65% by volume,
• wherein said at least one partially polymerized reactive thermoplastic prepolymer has a molten viscosity of 0.1 to 100 Pa.s,
• wherein a preimpregnation step is done using an aqueous dispersion of prepolymer particle or an emulsion or aqueous suspension of prepolymer, a fluidized bed or spraying of a nozzle or spray gun by dry route in a tank, excluding a molten route, the fluidized bed having at least one supporting part which includes a compression roller,
• wherein the at least one reactive thermoplastic prepolymer is selected from:
• polyaryl ether ketones (PAEK);
• polyaryl ether ketone ketone (PAEKK);
• aromatic polyether imides (PEI);
• polyaryl sulfones;
• polyarylsulfides;
• polyamides (PA);
• PEBAs;
• polyolefins;
• and mixtures thereof,
• wherein said at least one partially polymerized reactive thermoplastic prepolymer comprises at least two polyamide prepolymers that react together and each carry respectively two identical terminal functions X′ or Y′, where said function X′ of a prepolymer can react only with said function Y′ of the other prepolymer.