Mixtures of elastomers SKEP-50, SKEPT-60 with technical carbon of P-234 mark have been produced under industrial conditions and content of indissoluble phase in them has been determined. It is established that with increase in a quantity of technical carbon in mixtures, amount of washed rubber  decreases. It is explained by that with increase in amount of filler binding intensity on the boundary filler–rubber increases, binding intensity on the boundary filler–SKEPT-60 being higher than on the boundary filles–SKEP-50.