Adhesive bonding method for automated processes

A method for adhesively bonding two substrates S1 and S2, comprising the steps:

• a) applying a liquid, radiation-curable primer composition P onto the surface of substrate S1;
• b) curing the liquid, radiation-curable primer composition P by applying radiation with a suitable wavelength, intensity and temporal exposure such that the radiation-curable primer composition P is cured into a solidified, coherent or interrupted layer adhering to the surface of substrate S1;
• c) optionally storing the primed substrate S1 for a time of up to 6 months;
• d) applying a curable adhesive composition A onto the cured primer composition P on substrate S1;
• e) joining substrate S2 to the adhesive composition A on substrate S1 such that an adhesive bond is formed between substrate S1 and substrate S2, wherein the surface of substrate S2 to be adhesively bonded is optionally pre-treated to improve adhesion before step e) is performed;
• f) curing the curable adhesive composition A;
• wherein
• the liquid, radiation-curable primer composition P comprises:
• at least one radiation-polymerizable monomer,
• at least one photosensitizer, photosynergist, photoinitiator, and/or catalyst suitable to induce or accelerate radiation curing of the radiation-polymerizable monomer;
• optionally at least one radiation-curable polymer;
• optionally further additives selected from the group consisting of pigments, fillers, rheology modifiers, stabilizers, tougheners, and surfactants;
• wherein the radiation-curable primer composition P contains less than 5% by weight of solvents, in relation to the whole primer composition P.