Patent DE-102009002718-A1 (DE)
Title: Corrosion-protective coating of metal strip, comprises applying an organic coating containing a metal compound and/or a metallic pigment on the metal surface, and optionally initially cleaning and degreasing the metal surface
Inventor: KOCH MATTHIAS
IPC: C23C16/40
Filed: 2009-04-29
Abstract: The method for corrosion-protective coating of metal strip, comprises applying an organic coating containing a metal compound and/or a metallic pigment on the metal surface, optionally initially cleaning and degreasing the metal surface, applying an oxide thin layer containing 30 wt.% of silicon on the optionally cleaned and degreased metal surface, optionally modifying the oxide thin layer containing silicon with organosilanes in an adhesion-promoting manner, and coating the metal surface with a hardenable coating agent containing an organic binder system. The method for corrosion-protective coating of metal strip, comprises applying an organic coating containing a metal compound and/or a metallic pigment on the metal surface, optionally initially cleaning and degreasing the metal surface, applying an oxide thin layer containing 30 wt.% of silicon on the optionally cleaned and degreased metal surface, optionally modifying the oxide thin layer containing silicon with organosilanes in an adhesion-promoting manner, coating the metal surface with a hardenable coating agent containing an organic binder system and metal compounds and/or metallic pigments as component a, where the metal compound and/or the metallic pigment consists of metallic element (Me), which occupies an electrochemical standard potential of E 0>0>(Me 0>/Me n>+>) that is larger than the electrochemical standard potential of iron E 0>0>(Fe 0>/Fe 2>+>), and hardening the coating agent thermally and/or using actinic radiation. The silicon-containing oxide thin layer is applied from the gas phase to the metal strip in a layer thickness of 20 nm but not more than 200 nm. The silicon-containing oxide thin layer applied from the gas phase is produced in a pyrolytic process, in which the organosilane is mixed to a combustible carrier gas, where the organosilane is introduced together with the carrier gas into a flame for combustion. The oxide thin layer is formed inside a surface of the metal strip limited by the flame. The portion of metal compounds and/or metallic pigments is collectively 0.5 wt.% related to the total coating agent but it does not exceed more than 10 wt.% and is calculated as the sum of the respective metallic elements. The weight portion of the organic binder system is 40-90 wt.% related to the total composition of the coating agent. The organic binder system of the coating agent contains component b, c and d. The coating agent additionally contains 0.1-10 wt.% of initiator or initiator mixture for free radical polymerization as component e contained related to the total composition of the coating agent. The coating agent additionally contains component f and g. The weight portions of the components a, b, c, d, e, f and g of the coating agent add to 90 wt.%, where the weight portion of the further components is less than 10 wt.%. The coating agent contains less than 5 wt.% of components, which are not produced in the developed layer by polymerization during hardening and have a boiling point of 250[deg] C than pure component at normal pressure. The coating agent is applied in a quantity, so that a layer weight of the coating agent results 2 g/m 2>but less than 8 g/m 2>. An independent claim is included for a coated metal strip or metal sheet divided from the metal strip.