TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The component (i) comprises tert-butyl-per-2-ethylhexanoate (TBPEH) or Tert-amyl-per-2-ethylhexanoate (TAPEH). The component (ii) comprises monoperoxycarbonate of formula (R6OO-C(=O)O-R7) (II), preferably tert-butylperoxy(2-ethylhexyl)-carbonate, alkyl peroxide of formula (R3OO-R4-OOR5) (III) or (R3-OO-R5) (IV), preferably 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane (DHBP), di(tert-butyl)-peroxide (DTBP) or 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexyne-3 (DYBP), cyclic peroxide of formula (V), preferably 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane (HMCN) or 3,3,5,7,7-pentamethyl-1,2-4-trioxepane (cyclic MEKP), perketal of formula (R11OO-C(R12)(R13)-OOR14) (VI), preferably 1,1-bis(tert-butylperoxy)cyclohexane (CH), 1,1-bis(tertbutylperoxy)-3,3,5-trimethylcyclohexane (TMCH), 2,2-di(tert-butylperoxy)butane (BU), ethyl-3,3-di(tert-butylperoxy)-butanoate (EBU) or 4,4-bis-(tert-butylperoxy)-valeric acid-n-butylester (NBV) or hydroperoxide of formula (R15OOH) (VII), preferably tert-butylhydroperoxide (TBHP). The peroxide mixture comprises a combination of tert-butyl-2-2-ethylhexanoate with at least one additional peroxide comprising tertbutyl(2-ethylhexyl) carbonate (TBPEHC), 2,5-dimethyl-2,5-di(tert-butylperoxy) hexane (DHBP) or 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (TMCH). The peroxide mixture comprises at least 1 wt.% and not greater than 99 wt.% of peroxide. The amount of added the peroxide mixture is 0.1-5 wt.%, based on the polymer. The premixture is present in granulate- and/or powder form. The amount of peroxide is 0.5-75 wt.%, based on the total weight of the premix.R6, R7, R3, R5, R11, R14, R15 = alkyl;R4 = alkylene or alkynylene;R8, R9, R16 = alkylene; eitherR12, R13 = hydrocarbon comprising at least one hetero atom; orR12+R13 = cyclic group; andn = 0-5, preferably 0-2.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The crosslinkable polymer (0.5-75 wt.%), preferably crosslinkable ethyl vinyl acetate is added to the peroxide mixture. The step (ii) is carried out in a molding machine, preferably in a film extrusion system. EXAMPLE - Typical peroxide mixture comprised of (in %): tert-butyl-2-2-ethylhexanoate (1) and tert-butyl(2-ethylhexyl)carbonate (0.1).