Prepreg of thermoplastic polymer particles in liquid thermosettable resin

Claim 1

A prepreg comprising reinforcing filaments and a hot melt coatable thermosettable resin composition comprising: a) a thermosettable mixture that is liquid at a temperature in the range of 20° to 100° C. comprising one or more thermosettable resins and one or more curatives for the thermosettable resins and b) resin particles of one or more amorphous thermoplastic polymers, said particles being dispersed in the thermosettable mixture at a temperature below the dissolution temperature of the particles, the particles having an average diameter in the range of 0.5 to 50 micrometers, a surface area of at least 1.0 m 2 /g, and a dissolution temperature of 50° C. or higher and being essentially insoluble in the thermosettable resin at temperatures up to 15° C. below the dissolution temperature; said resin composition being free of solvent for the thermoplastic particles and having a viscosity that decreases with increasing temperature up to a dissolution temperature and that increases with increasing temperatures at temperatures above the dissolution temperature, said amorphous particles being completely dissolved in the thermosettable resin at a temperature at least 20° C. below the cure temperature of the resin, and providing a homogeneous cured resin composition.