Culminal Plus is a new series of modified methylcelluloses for use in premium cementitious tile adhesives. Cementitious tile adhesives are clearly specified in EN 12004/ISO 13007 as to their performance. All tests are typically done under well-controlled laboratory conditions specifying temperature, humidity and substrate. Often formulations are designed to meet the norms but when it comes to practical application in the field the conditions always differ and lead to lower performance and, in the worst case, to costly complaints. Culminal Plus was designed by Ashlands research & development experts to improve important tile cement properties and give additional security.
The main benefits of using Culminal Plus versus commonly used methylcellulose based rheology modifiers are:
Better “transfer” of adhesive through improved open time
When tilers apply tile adhesive typically a larger area is covered before tiles are placed. Due to the longer visual open time and resulting improved contact area using Culminal Plus better bonding and higher strength values are achieved. This is especially important when larger format tiles are placed. Ideally the reverse side of each tile, even when applied after a long time, should be fully covered with adhesive after the tile is placed and pressed into the mortar. This to secure maximum adhesion.
Optimized fracture patterns
Culminal Plus improves the fracture pattern significantly in three formulations shown in the Figure. All tested products show an improved fracture pattern and it is obvious that the Culminal Plus containing products show 100 % cohesion failure after norm storage.
Higher strength values after longer embedding time
Especially when application conditions in the field (higher temperature, low humidity, wind, strong absorbing substrates) increase the risk of early skin formation on the adhesive surface it is important to maximize open time. Culminal Plus allows easier development of formulations classified as “tile adhesives with long open time (e.g. C2TE)”.
The higher the strength values even after long embedding time, the higher the probability of the tile adhesive to show also excellent performance under practice conditions.
Comparing Culminal Plus with a standard methylcellulose shows that after short embedding time the strength values are comparable. The product containing Culminal Plus, however, shows clearly higher strength values when tiles are embedded after a longer time.