Metal effect pigment-free radar-compatible coating on a substrate

A process for the production of a metal effect pigment-free radar-compatible coating comprising flake-form effect pigments on a substrate, said process comprising:

• applying a first layer to the substrate, said first layer comprising at least one absorbent pigment and is free from flake-form effect pigments to form a coated substrate, wherein said substrate comprises a plastic plate or plastic film, and
• applying a second layer to the first layer of the coated substrate, said second layer comprises flake-form effect pigments having absorbent properties is applied to the first layer in an amount of at least 10% by weight, based on the weight of the solid layer,
• wherein the second layer is applied as a single layer or in two or more part-layers arranged one above the other and drying is carried out after application of each layer, and
• wherein the second layer, when it is applied over the full area of a black/white background in a layer thickness of 14±2 μm and is measured spectrophotometrically in the L*,a*,b* colour space at an illumination angle of 45° and at a viewing angle of 75°, has a colour separation ΔE* between the coated black background and the coated white background of 0 to 20.