The present invention relates to a cationically polymerizable composition comprising or consisting of: (a1) 35 to 90 wt % of at least one (meth)acrylic ester of the general formula (I) in which R1 is selected from H and CH3 and R2 is a linear or branched alkyl chain having 1 to 30 carbons; (a2) 5 to 30 wt % of at least one olefinically unsaturated monomer having at least one cationically polymerizable functional group; (a3) 5 to 30 wt % of at least one alkoxysilane-modified (meth)acrylic ester; (a4) optionally 5 to 30 wt % of at least one N-vinyl-substituted lactam; and (a5) optionally up to 5 wt % of at least one (meth)acrylic ester different from (a1) and/or of at least one olefinically unsaturated monomer which is copolymerizable with components (a1) to (a4). The invention further relates to a pressure sensitive adhesive and also to a structural pressure sensitive adhesive, which are obtainable by polymerization and optional subsequent additional crosslinking of such a composition, and also to the use of these pressure sensitive adhesives.