The present invention relates to an adhesive producible from an aqueous polyurethaneurea dispersion comprising an amorphous polyurethaneurea (V1) obtainable by reacting at least A) one aliphatic, cycloaliphatic or araliphatic polyisocyanate component having an average isocyanate functionality of ≥1.8 and ≤2.6, B) one polyetherpolyol component, C) one amino-functional chain extender component having at least 2 isocyanate-reactive amino groups, containing at least one amino-functional compound C1) that does not have any ionic or ionogenic groups and/or an amino-functional compound C2) that has ionic or ionogenic groups, D) optionally further hydrophilizing components different than C2), E) optionally hydroxy-functional compounds having a molecular weight of 62 to 399 mol/g, F) optionally further polymeric polyols that are different than B), G) optionally one compound having exactly one isocyanate-reactive group or one compound having more than one isocyanate-reactive group, where only one of the isocyanate-reactive groups reacts with the isocyanate groups present in the reaction mixture under the reaction conditions chosen, and H) optionally one aliphatic, cycloaliphatic or araliphatic polyisocyanate component having an average isocyanate functionality of >2.6 and ≤4, where components B) and F) together contain ≤30% by weight of component F), based on the total mass of components B) and F) and a hydrophilic polyisocyanate (V2) preparable at least from the components of I) an aliphatic, cycloaliphatic or araliphatic polyisocyanate component having an average isocyanate functionality of preferably ≥2.0 and ≤3.6, J) a polymeric, hydrophilic and monofunctional polyalkylene oxide component, K) optionally further hydrophilizing components different than J), L) optionally admixtures and auxiliaries. The invention likewise provides an adhesive layer and a product including the adhesive, a process for producing the adhesive layer, a specific polyurethaneurea, and the use of the adhesive and a kit having components (V1) and (V2).