Method for coating metallic surfaces with an aqueous composition

Abstract

A process for producing a repair coating on at least one metallic surface that is coated with at least one corrosion protecting coating A applied with at least one composition selected from the group of pretreatment compositions, of organic compositions and of silicon compound(s) containing compositions, whereby the at least one corrosion protecting coating A has been at least partially removed in the area Z, whereby a thin corrosion protecting coating B containing at least one silicon compound is applied with a solution or dispersion containing at least one silane, at least one silanol, at least one siloxane, at least one polysiloxane or any mixture of these (=''siloxane composition'') on at least a part of the area Z. Optionally, a further corrosion protecting coating C may be applied on the thin corrosion protecting coating B generated with the siloxane composition whereby the at least one further corrosion protecting coating C is generated with at least one organic composition like a primer, a wet-primer, an e-coat, a powder coat, a base-coat or a clear-coat or with at least one composition which is the same or another siloxane composition as for the thin film B.

Description

technical field

[0001] The present invention relates to a method for coating metal surfaces with an aqueous composition comprising at least one silane or / and related compound and at least one further component. The invention also relates to the use of corresponding aqueous compositions and substrates coated according to the method of the invention. Background technique

[0002] By far the most widely used method of treating metal surfaces, especially parts, coils or coil parts made of at least one metallic material, or for pre-treating metal surfaces prior to painting them is generally Based on the use of chromium(VI) compounds on the one hand, optionally together with various additives, or on the other hand on the use of phosphates, e.g. zinc / manganese / nickel phosphates, optionally together with various additive.

[0003] Due to the toxicological and ecological risks associated in particular with the use of chromate- or nickel-containing methods, alternatives to these met...