Impregnation resin mixture

The use of an impregnation resin mixture for the production of insulation of a conductor to be insulated, for a process comprising:

• (I) providing an insulation tape comprising a nonconductive material and a reinforcement layer, with the nonconductive material and the reinforcement layer adhesive-bonded to one another by a composition comprising:
• a) at least one epoxy resin component, one novolac, or both, wherein the molar mass of any novolac comprising 250 to 1000 g/mol,
• b) BCl3, BCl3 complexes, imidazoles compounds, and combinations thereof, and
• c) optionally further additives,
• (II) winding the insulation tape around the electrical conductor and
• (III) impregnation of the insulation tape wound around the conductor with an impregnation resin mixture comprising the following constituents:
• d) at least one epoxy resin component selected from the group of the polyepoxides based on bisphenol A and/or F and of advancement resins produced therefrom, based on epoxidized halogenated bisphenols and/or on epoxidized novolacs, and/or polyepoxy esters based on phthalic acid or hexahydrophthalic acid, or based on terephthalic acid, or of epoxidized polyaddition products made of dicyclopentadiene and phenol or of cycloaliphatic compounds,
• e) 2 to 30% by weight of lactones, based on the entirety of the epoxy resin components, and
• f) optionally further additives,
• where the impregnation resin mixture and the composition of the insulation tape comprise no carboxylic anhydrides.