Matting agent properties

Matting agents with smaller average particle size do not give a quality matting effect, but they produce smooth paint films. In contrast, products with larger particle sizes are stronger in matting efficiency but the paint film surface is not so smooth.

Matting additives with large particles show a tendency to build up separation and sedimentation in clear paint systems during storing time. Untreated silicas and fillers, in particular, need to be combined with anti-settling agent or fine particle size waxes to avoid these phenomena. Fine particle size waxes and easy to disperse hydrophobic pyrogenic silicas are recommendable, as they have a similar refractive index to these additives.

The equal refractive index of silica, wax and organic matting to resin systems which are commonly used in paints are one reason for their popularity. Substrates like wood, foils, and leather (natural & artificial) must be coated with transparent coating systems. It is of prime importance to select an application that has little influence on transparency, and also to choose a resin and matting agent which have similar ‘refractometers’, as this also improves the transparency of the system. The amount of matting agent added to the paint film also impacts upon transparency. More efficient matting agents require lower dosing levels and therefore provide better transparency.