The invention relates to diisocyanates comprising radiation-curable groups and organopolysiloxane-polyurea block copolymers of general formula (II), which can be obtained therefrom and can be crosslinked using radiation. In said formula (II), (A) can be identical or different and represents a unit of formula (III), (B) can be identical or different and represents a unit of formula (IV), and (C) can be identical or different and represents a unit of formula (V), the radicals and indices having the meanings indicated in claim 1, provided that at least one radical L is supplied in the molecule while the individual blocks (A), (B), and (C) can be statistically distributed in the polymer.