Patent ID: 7709058

Claim:
A process for coating metal substrates, in which the metal is cleaned, if necessary, comprising steps of: a) contacting a metal substrate with a conversion solution comprising at least one simple or complex salt of at least one metal M, such that a conversion layer that contains 0.01 to 0.7 mmol/m 2 of metal M is produced; b) optionally flushing with water and/or drying the metal substrate; c) applying to said conversion layer on said metal substrate a coating agent comprising: c1) 5 to 30 percent by weight of one or more aliphatic cross-linking urethane resins; c2) 10 to 30 percent by weight of one or more cross-linking agents for c1); c3) 4 to 30 percent by weight of one or more corrosion-protection pigments, with the remainder of the coating agent comprising one or more organic solvents and/or water, and optionally other active and/or auxiliary substances; wherein no more than 5% of carbon atoms in said resin are present in aromatic and/or unsaturated groups and d) curing the coating applied on the conversion layer on the metal substrate in step c) by heating to a substrate temperature of at least 100° C.