Classification of Aluminum paste
A lubricant must be used in the various production processes to avoid coldwelding. This has a typical effect on the wetting behaviour of the metallic pigments，A distinction is drawn between leafing and non-leafing pigments.
Due to their high surface tension leafing pigments are not wetted by the binder and therefore float on the wet film. This effect is achieved by the use of e.g. stearic acid as lubricant.
In paint systems with strongly polar solvents or binders there is always a danger that the leafing pigments will "drown" through wetting and turn into non-leafing pigments. This possibility must be taken into account when drawing up the formula of paints. If necessary special leafing stabilized pigments should be used
Non-leafing pigments are created either by the addition of strongly polar substances or wetting agents to leafing pigments or by the use of special lubricants (e.g. oleic acid) directly in the milling process.
Non-leafing pigments are completely wetted and thus spread evenly throughout the entire paint film.