SOLVENT-BASED PRETREATMENT AGENT HAVING IMPROVED ADHESION TO RESIDUAL ADHESIVE BEADS

摘要

The present invention relates to a pretreatment agent for bonding operations, containing i) between 10 and 30 parts by weight of at least one polyurethane polymer PU containing isocyanate groups, obtained by reacting at least one poly(meth)acrylate polyol P and at least one polyisocyanate I1, with the proviso that the poly(meth)acrylate polyol P has an OH number of at least 35, and the polyurethane polymer PU has an NCO content of between 2.0 and 25.0 wt.% in relation to the polyurethane polymer PU; ii) 0.1 to 10 parts by weight of at least one organosilane OS; iii) 0 to 10 parts by weight of at least one further polyisocyanate I2; iv) 60 to 90 parts by weight of a solvent L; v) 0 to parts by weight of a carbon black; vi) 0 to 10 parts by weight of a pyrogenic hydrophobic silica. The pretreatment agent according to the invention has particularly good properties to allow very good adhesion of an adhesive to many substrates, in particular glass, ceramic, paint, and old residual adhesive beads. Furthermore, the pretreatment agent can be formulated to be clear and transparent and largely colourless.