The present invention relates to hydrogenated carboxylated nitrile-butadiene rubber (HXNBR), which contain molecularly dispersed triphenylphosphine, and which is useful as a cross-linking agent for elastomers, plastics and/or adhesive systems. The present invention also relates to products which are obtainable from the HXNBR having molecularly dispersed triphenylphosphine and elastomer, plastics and/or adhesive systems, a composition containing a HXNBR having molecularly dispersed triphenylphosphine and further non-molecularly dispersed activators, a process for the preparation of the composition as well as the use of HBR having molecularly dispersed triphenylphosphine, as an elasticizing agent for elastomer, plastics and/or adhesive systems.