Method for coating metal surfaces, prior to forming, with a paint-like coating and use of substrates so coated

摘要

Surface coating of metal comprises pretreatment with an aqueous composition (I), which can be (largely) free from chromium(VI) (Cr-VI) compounds, before applying other coatings and optionally shaping. (I) contains organic film-forming agent(s) containing water-soluble or -dispersible polymer(s), inorganic compound(s) in particles (II) and lubricant(s) or/and organic corrosion inhibitor(s). Surface coating of metal, especially aluminum (Al), iron (Fe), copper (Cu), magnesium (Mg), nickel (Ni), titanium (Ti), tin (Sn), zinc (Zn) and alloys of these, comprises pretreatment with an aqueous composition (I), which can be largely or completely free from chromium(VI) (Cr-VI) compounds, before applying coatings and optionally shaping, especially in the case of strip or sections of strip. (I) contains organic film-forming agent(s) containing water-soluble or -dispersible polymer(s) with acid number 5-200, inorganic compound(s) in particles (II) of average diameter 0.005-0.3 Microm (scanning electron microscope) and lubricant(s) or/and organic corrosion inhibitor(s). It may also contain organic solvent(s), silane or/and siloxane, cross-linker, especially based on a basic compound, and/or Cr-VI compound(s). The clean metal surface is contacted with (I) to form a film containing particles, which is then dried and optionally cured to give a 0.01-10 Microm thick film, as determined by peeling a definite area of the cured film and weighing. An independent claim is also included for aqueous composition (I) for pretreating metal surface before further coating or treatment.