How to Choose the Most Effective Matting Agent?

  According to the Syloid product range technical studies of Grace - one of the world's largest silica producers – three main factors must be considered for matting efficiency: porosity, particle size and surface treatment. Additionally, dry film thickness and other dynamics affecting film surface such as resin type, solid content (or non-volatile compounds), solvent type and drying time are also important factors. In Graphic 1, three different matting agents with the same particle size but different pore volumes are shown. The higher the pore volume of the silica, the more efficient the SYLOID® silica grade. Graphic 1. Matting efficiency of 3 silica matting agents with equivalent particle size, but different pore volume In Graphic 2, three different matting agents with the same pore volume but different particle sizes are presented. The larger the average particle size, the higher the matting efficiency. Optimum matting efficiency with acceptable paint film properties can only be achieved by selecting the SYLOID® matting agent with an appropriate particle size in relation to the dry thickness of the coatings film.

Graphic 2. Matting efficiency of 3 silica matting agents with equivalent pore volume, but different average particle size

Some SYLOID® silica products are surface treated with carefully selected organic compounds (e.g. waxes). The wax treatment prevents settling, particularly the formation of hard sediments, especially in low-viscosity clear lacquers. Wax-treated products can also contribute positively to improving other surface properties, such as mar and scratch resistance. Wax-treated products can exhibit lower matting efficiency than untreated products with similar particle size. Besides the silica matting agent, other formulation and application properties influence the final gloss. Graphic 3. Matting efficiency of treated and untreated silica matting agents with equivalent pore volume and particle size. The higher the film weight at a given addition level of a selected matting agent product, the lower the matting effect. To matt thick films effectively, selection of the largest acceptable particle size product is recommended.

Graphic 4. Influence of film thickness on gloss

As the required addition level of matting agents to achieve a defined gloss depends on the amount and the dynamics of film shrinkage that occurs during drying, the matting efficiency of SYLOID® matting agents can also be influenced by: • The resin system (different curing mechanisms), • The solids content (or the amount of volatile compounds such as solvents), • The type of solvent (differing vapor pressure), • The drying method (fast or slow drying). Graphic 5. Matting efficiency of a given silica matting agent in different clear lacquer systems To determine the most effective matting agent for your system, consult GRACE- SYLOID® product brochures online and contact Nordmann Turkey directly as their local distributor.