Silica particles for durable water-borne wood coatings

When making the switch from solvent to water-borne wood coatings, the goal is to not compromise the function and performance. As per research, epoxy silane-modified colloidal silica can contribute to improve block resistance and sanding properties of water-borne clear coats.

Very few studies have been done on the use of silane-modified water-based colloidal silica particles in formulations of water-borne coatings. Recently there has been great interest in such particles in water-borne lacquers as they have shown to provide benefits like anti-blocking, sanding and wood grain accentuation in acrylic emulsion-based wood coatings.

Recent research has confirmed the effect of adding silane-modified colloidal silica to water-based clear coating formulations on open time and on the anti-blocking, sanding and mechanical properties.

While no changes in gloss levels in compression to a reference system without any silica particles could be found, other properties changed quite a bit. Depending on the test system and the amount of particles blocking and sanding resistance grew strongly. The best results were obtained for the test system with highest tack.

However, the effect of silica on abrasion resistance is very formulation dependent. Distribution of silica in the matrix and the degree of cross-linking of silica in the matrix are important factors; i.e. there is a big difference between one-pack and two-pack systems.



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