"ixture) is conceivable and is also realized within this framework.In a particularly preferred embodiment of the invention 10 to 150 parts by weight of silicas, consisting completely or partially of the silicas according to the invention, if required, together with 0 to 100 parts by weight of carbon black and 1to 10 parts by weight of an organosilicon compound, each in relation to 100 parts by weig" . . . .