Wet strength and durability, two key properties for outdoor tile applications

R. Zurbriggen, R. Duss, H. Waser, Nouryon Chemicals AG, Sempach Station, Switzerland

Outdoor weathering conditions require high performing systems which can stand dry-wet, hot-cold and freeze-thaw cycles over several years of a building‘s service life. New redispersible polymer powders (RPPs) allow the development of easy to apply dry mix mortars which provide even better adhesion strength than commercial 2-component systems.
The development of these RPPs was accompanied by a research study on the interaction mechanisms between polymer and cement. The key finding was that during the period of application, the polymer must act very neutral against cement in order to provide ideal workability properties, while during setting and hardening the polymer must become reactive and form a dense and strong polymer-cement matrix.
Key words: polymer-modified mortar, tile adhesive, dry mix, redispersible polymer powder, outdoor application.