METHOD FOR PRETREATING AND COATING METAL SURFACES, PRIOR TO FORMING, WITH A PAINT-LIKE COATING AND USE OF SUBSTRATES SO COATED

摘要

The invention relates to a method for coating a metal strip for use in the automotive, aircraft or aerospace industry. The strip or the strip sections produced on the basis thereof in a later step is/are first coated with at least one anticorrosive coating and then with at least one coating of a paint-like polymer-containing coating. The strip, once coated with at least one anticorrosive coating or once coated with at least one coat of a paint-like coating, is divided up in strip sections. Said coated strip sections are then formed, joined and/or coated with at least one (further) paint-like coating and/or coat of paint. The paint-like coating is achieved by coating the surface with an aqueous dispersion that contains, in addition to water, at least one UV-crosslinkable water-soluble and/or water-dispersible resin, at least one wax as the forming additive, at least one photoinitiator, and at least one corrosion inhibitor. The coating is dried and cured once it has been applied to the metal surface, thereby forming a coating that has a thickness of up to 10 mu m once cured. A test surface deformed in a mandrel bending test according to DIN ISO 6860 however without superficially cracking the test surface using a mandrel with a diameter of from 3.2 mm to 38 mm, does not show any signs of corrosion > 5 % in a directly subsequent test in a saturated atmosphere according to DIN 50017 KFW over a period of 240 hours. The invention also relates to a corresponding coating method, according to which the strip is first coated with at least one paint-like polymer-containing coating without prior application of an anticorrosive coating.