The invention relates to a bilayer pressure-sensitive adhesive. Provision is made for the bilayer pressure-sensitive adhesive to comprise an apolar layer and a polar layer, the apolar layer and the polar layer each comprising a polyacrylate pressure-sensitive adhesive having a static glass transition temperature of not more than +15° C., and the surface energy of the apolar layer differing from the surface energy of the polar layer by at least 5 mN/m.