The present invention relates to storage-stable prepregs (preimpregnated fibers) on the basis of lightfast, low-viscous polyurethane systems with an increased characteristic number and flat fiber composite components (molded bodies; composite compounds) produced therefrom, which can be obtained by methods of impregnation of, for example, woven fabrics and laid scrims, and to a method for the production thereof. The polyurethane system can comprise a reaction product of a reaction mixture of an isocyanate component and a polyol formulation. The isocyanate component comprises an organic isocyanate. The polyol formulation comprises a polyol component, a dianhydrohexitol, a latent catalyst, and optionally auxiliaries and/or additives.