Abstract: The invention relates to a method for producing duroplastic fine-fiber non-wovens, characterized in that: a) melts of reactive three-dimensionally cross-linkable, non-linear prepolymers are extruded by nozzles; b) the exiting melts are blown by means of hot air to form fine fibers; c) the fine fibers are separated by the flow of air and deposited to form a non-woven comprised of a fine-fiber weave; d) the non-woven is subsequently compacted, and; e) the non-woven is treated with a medium that initiates a three-dimensional cross-linking, and the fine fibers in the non-woven are inherently bonded and/or hardened in a subsequent thermal post-hardening. This enables duroplastic fine-fiber non-wovens to be economically produced that have both a high flame retardant effect as well as a high thermal protection, sound insulation and filtering capacity.