What are the factors influencing silica matting efficiency?

The following silica properties create a big impact on final matting efficiency of paints & coatings products:

 

  • Pore Volume: The porosity of silica indicates the amount of internal voids in the silica particle. The higher the pore volume of the particles, the lighter is the density of silica and the more efficient is matting agent due to the higher number of particles per unit weight.

  • Particle size: The larger the average particle size, the higher the matting efficiency. This is due to the larger particles creating the highest degree of surface micro-roughening. However, it may result in unacceptable surface appearance and haptic properties, if it is too coarse. Optimum matting efficiency can be achieved by selecting the right matting agent with an appropriate particle size in relation to the dry thickness of the coatings film.

  • Surface treatment: Some silica products are surface treated with organic compounds (e.g. waxes) and exhibit a lower matting efficiency than untreated products with similar particle sizes. The wax treatment prevents settling or particles sedimentions in production processes.

  • Dry film thickness: The higher the film weight the lower the matting effect. To matt thick films effectively, the selection of the largest acceptable particle size matting agents is recommended.

  • Other factors: The matting efficiency of silica matting agents can also be influenced by: the resin system; the solids content; the type of solvent (differing vapour pressure); the drying method (fast or slow drying) etc.

 

Have questions in choosing matting agents? Please contact us for further discussion and consultation for right products and formulations selections.

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