Process for the production of a dark-color multi-layer coating

A process for the production of a dark-color multi-layer coating, comprising the successive steps:

• (1) applying an NIR-opaque coating layer A′ from a waterborne pigmented coating composition A to a substrate,
• (2) applying a coating layer B′ from a waterborne pigmented coating composition B onto the substrate provided with coating layer A′,
• (3) subjecting the coated substrate obtained in step (2) to a drying step,
• (4) applying a clear coat layer from a clear coat composition onto the coated substrate obtained in step (3), and
• (5) curing the coating layers applied in steps (1), (2), and (4) simultaneously;
• wherein both waterborne coating compositions A and B comprise aqueous microgel and sheet silicate,
• wherein the pigment content of coating composition A comprises <90 wt. % of aluminum flake pigments and is composed in such a way that NIR-opaque coating layer A′ exhibits low NIR absorption,
• wherein the pigment content of coating composition B consists 50 to 100 wt. % of at least one black pigment with low NIR absorption and 0 to 50 wt. % of at least one further pigment, which is selected in such a way that coating layer B′ exhibits low NIR absorption and that the dark-color multi-layer coating exhibits a brightness L* (according to CIEL*a*b*, DIN 6174), measured at an illumination angle of 45 degrees to the perpendicular and an observation angle of 45 degrees to the specular, of at most 10 units, and
• wherein the sum of the respective wt. % equals 100 wt. %.