Abstract: A self-bonding coating composition for the production of electrical steel sheets cores comprising A) 100 parts per weight of at least one epoxy resin based on bisphenol-A-type and/or bisphenol-F-type, 100% of solids, B) 0.1 to 200 parts per weight of nano particles having an average radius ranging from 2 to 600 nm, C) 0 to 25 parts per weight of at least one curing agent selected from the group consisting of dicyandiamide, blocked isocyanate and Lewis acid or selected from the group consisting of phenolic resin, carboxylic acid, anhydride and Lewis acid, 100% of solids, D) 0.1 to 10 parts per weight of at least one additive, and E) 50 to 200 parts per weight of water or at least one organic solvent, ensuring increased re-softening temperatures as well as excellent bonding strength, corrosion resistance and electrical insulation of the coating.