Patent ID: 11142827

Abstract:
A method for anti-corrosion pre-treatment of metal substrates using zirconium-based aqueous anti-corrosion agents comprising polycyclic hydrocarbons that have at least one anellated benzene ring, each having at least two ring-substituted hydroxyl groups in ortho position to each other. The aqueous anti-corrosion agent can be substantially free both of passivating chromium-containing compounds and of fluoride-containing compounds that pickle the metal substrate. Pre-treatment by drying (dry-in-place method) is especially advantageous. Accordingly, the method according to the invention is suitable in particular for the pre-treatment of metal strip, wherein excellent anti-corrosion results are achieved on surfaces of aluminum or steel. The invention further relates to a method for producing coated can lids from aluminum strip by using the previously mentioned zirconium-based anti-corrosion agent. A further aspect comprises an aqueous concentrate for providing the ready-to-use anti-corrosion agents.