Composition and thermoplastic molding compound having good notch impact strength and improved melt stability

A composition for production of a thermoplastic moulding compound, wherein the composition consists of the following constituents:

• A) 30% to 90% by weight of at least one polymer selected from the group consisting of aromatic polycarbonate, aromatic polyester carbonate, and aromatic polyester based on the total weight of the composition,
• B) 5% to 65% by weight of a polymer free of epoxy groups based on the total weight of the composition, the polymer free of epoxy groups consisting of
• B1) a rubber-modified vinyl (co)polymer prepared by the emulsion polymerization method and,
• B2) optionally, a rubber-free vinyl (co)polymer,
• C) 0.5% to 10% by weight of a block or graft polymer comprising structural elements deriving from styrene and at least one epoxy-comprising vinyl monomer based on the total weight of the composition,
• D) 0.001% to 20% by weight of one or more further additives based on the total weight of the composition,
• wherein component A has a proportion by weight of phenolic OH groups of 50 to 2000 ppm,
• wherein component C has a weight ratio of structural elements deriving from styrene to those deriving from epoxy-comprising vinyl monomer of 100:1 to 1:1,
• and wherein at least one of the composition constituents comprises a Brønsted-acidic and/or Brønsted-basic compound.