NOVELTY - Prepreg comprises a mixture of a fibrous reinforcement and an resin containing 20-85 wt.% of an epoxy resin having an epoxy equivalent weight (EEW) of 150-1500. The resin is curable by an externally applied temperature of 40-110 degrees C, preferably 70-110 degrees C and/or 60-90 degrees C. The resin contains 0.5-5 wt.% of a curing agent. The curing agent comprises a urea curing agent and an imidazole curing agent.    USE - The prepreg is useful in a laminate and for the production of wind turbine structures including a wind turbine blade or component (all claimed).    ADVANTAGE - The prepreg: utilizes the resin containing the curing agent which is free of dicyandiamide, thus the resin is cured or curable in the absence of a dicyandiamide hardener; and can be cured in less than 8 hours, preferably less than 2 hours (all claimed), thus having a reduced cure time, while providing good mechanical performance, a desirable glass transition temperature in combination with the fibrous reinforcement of the prepreg.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a stack of prepregs containing the epoxy resin having EEW of 150-1500, where the stack contains at least 2 prepreg layers, preferably 40, 60 or more layers;    (2) a curable stack of prepregs, where the prepreg comprises a structural fibrous layer impregnated with the epoxy resin having EEW of 150-1500;    (3) a laminate comprising a cured prepreg or stack of prepregs;    (4) curing the epoxy resin within a prepreg or prepreg stack, comprising exposing the prepreg or prepreg stack to an externally applied temperature of 40-110 degrees C, preferably 70-110 degrees C and/or 60-90 degrees C for up to 8 hours at a pressure of less than 3 bar absolute, where the resin contains 0.5-10 wt.% of a curing agent and being free of a latent hardener;    (5) the production of wind turbine structures comprising providing the prepreg or stack of prepregs within a vacuum bag, placing the vacuum bag within a mold and creating a vacuum within the bag prior to or after placement in the mold and curing the epoxy resin by application of an externally applied temperature of 40-110 degrees C, preferably 70-110 degrees C and/or 60-90 degrees C for a period of 4-8 hours;    (6) a resin matrix comprising 20-85 wt.% of an epoxy resin having EEW of 150-1500; and    (7) a wind turbine blade or component produced from the resin matrix in combination with a fibrous reinforcement.