the invention provides rubber mixtures of at least one double bond - containing rubber , rubber gels and additives of inorganic peroxides and also optionally further fillers and rubber auxiliary substances . rubber mixtures according to the present invention are characterized in the uncrosslinked state by good processability and in the vulcanized state by improved mechanical properties in particular with regard to the product of the modulus at 100 % extension and the elongation at break and also by improved tensile strengths . in addition , vulcanizates prepared from rubber mixtures according to the present invention have a relatively low density , which has an advantageous effect on the weight of the rubber molded items prepared from the rubber mixtures . the vulcanizates are suitable for producing industrial rubber articles and for tire components .