Two of the main characteristics of metal varnishes are brilliance and luminance. Of particular significance is the "Flip-Flop" or two-tone effect, which is a result of the alteration of the luminance when the viewing angle changes.
This effect is a direct result of the metal pigment used and its adjustment in the varnish film.
The addition of certain additives promotes the "Flop" effect in metal effect varnishes. The appearance of the metal effect varnishes is influenced by the additive used and its particle diameter. Alternatively, products on a polymethyl urea resin base can be used.
The fine polymer particles lead to a spatial separation of the single metal pigment palettes in the varnish layer, and therefore, the "flop" effect is specifically targeted. The particles exert a barrier effect inside the varnish and surround the metal pigments with a frame structure that restricts their flexibility. This prevents undesired particle movement, achieving even more brilliance, and viewing from different viewing angles is enabled.
The appearance of metallic effect varnishes is also significantly influenced by the particle diameter of the additive used. The figure below shows the distribution of finely-ground polymethyl urea resin, measured with an ANALYSETTE 22 in an organic solution with a small volume dispersion unit.
This information has been sourced, reviewed and adapted from materials provided by FRITSCH GMBH - Milling and Sizing.
For more information on this source, please visit FRITSCH GMBH - Milling and Sizing.