Abstract: Cumene hydroperoxide oligomer according to Formula (I): in which OLIGOMER is a homo- or copolymer chain, which is substituted n times by the group which is in brackets; Q is absent or is a divalent aromatic C6-C14 hydrocarbon radical or an aliphatic, linear or branched C1-C14 hydrocarbon radical, which can be interrupted by one or more S and/or O atoms and/or —O—CO—NR1— and which can be substituted by one or more substituents; X, Y independently of each other in each case are absent, —O—, —COO—; —CONR3— or —O—CO—NR4—, wherein X is absent if Q is absent, and wherein the substitution on the aromatic compound is effected in position 2, 3 or 4 relative to the cumene hydroperoxide group; and n is a value from 1 to 50.