A DCDC voltage converter has a controller, two switches, a transformer and two rectifying diodes. , a melt viscosity of 2 to 20 000 mPas and a needle penetration of 1 to 50, and which contains at least one alkoxylated compound. The preferred transition metals are those of Groups 5, especially titanium and vanadium, Group 6, especially chromium or molybdenum, Group 7, especially manganese and Group 8, especially cobalt or nickel.