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. According to a recent article 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 since they have shown to provide benefits like anti-blocking, sanding and wood grain accentuation in acrylic emulsion-based wood coatings.
The article describes 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.
Stable gloss – improved mechanics
While the authors could not find changes in gloss levels in compression to a reference system without any silica particles, 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. The silica distribution in the matrix and the degree of cross-linking in the matrix are important factors; i.e. there is a big difference between one-pack and two-pack systems.
Further information on this study can be found in European Coatings Journal 7+8/2018. Subscribers of European Coatings 360° can find the article also online.
Event tip
If you want to learn all the important basics on waterborne systems, you may want to visit the European coatings seminar Waterborne coatings in Amsterdam in September 2018
