Thermoplastic molding compositions comprising, as substantive components, A) from 5% by weight to (99.99% by weight minus 1 ppb), based on components A) to D), of a polyoxymethylene homo- or copolymer, B) from 1 ppb to 1% by weight, based on the molding composition made from A) to D), of at least one polyethyleneimine homo- or copolymer, C) from 0.01 to 15% by weight of carbon black, and D) from 0 to 80% by weight of other additives, where the total of percentages by weight of components A) to D) is always 100%.