| abstract |
The present invention relates to a method for treatment of at least one surface of a substrate, wherein said surface is at least partially made of aluminum and/or an aluminum alloy, comprising at least a step of contacting said surface with an acidic aqueous composition (A), said acidic aqueous composition (A) comprising one or more metal compounds (M) selected from the group of titanium compounds, zirconium compounds and hafnium compounds and one or more linear polymers (P) containing (ml ) hydroxyethyl- and/or hydroxypropyl- (meth)acrylate, (m2) vinylphosphonic acid, and (m3) (meth)acrylic acid in form of their polymerized monomeric units, the one or more linear polymers (P) being comprised in the acidic aqueous composition (A) in an amount of 50 to 5000 ppm, based on the total weight of the acidic aqueous composition, to a corresponding acidic aqueous composition (A) as such, to a master batch to produce such acidic aqueous composition (A), to the use of the acidic aqueous composition (A) for treating surfaces and to substrates comprising the thus treated surfaces. |