PURPOSE: To obtain a mixture comprising an epoxy resin, an isocyanate resin and a specific reaction accelerator made of cyanoacetoamide, which has long pot life, excellent storage stability and heat-aging resistance, and is suitable for use in electric engineering and electronic engineering.

CONSTITUTION: This thermosetting resin mixture comprises the following. (A) At least one epoxy resin (most preferably aliphatic, alicyclic or aromatic epoxide). (B) At least one isocyanate resin (most preferably aliphatic, alicyclic or aromatic isocyanate). (C) Reaction accelerator of the formula I (R1=-(CR4R5)n- with n=2-24) halogen, nitro, 1-4C alkyl, formula II, formula III, formula IV; R2, R3 1-12C alkyl, halogen, nitro; R2, R3 form 5-7 membered heterocyclic ring in combination with N; R4, R5=H, 1-8C alkyl. (D) If appropriate, a filler and/or further additives conventional in industry.