Mortars for the Millions - Wacker Chemie AG

Mortars for the Millions

At the WACKER technical center in Brazil, an employee tests tile adhesives to check the tensile adhesive strength, which has been significantly improved with dispersible polymer powders.

Today, WACKER is a global market and technology leader in the field of polymeric binders based on vinyl acetate-ethylene (VAE) copolymers, which are sold around the world under the VINNAPAS® brand name. “Our binders are one of the chief ingredients of modern construction and tile adhesives, external thermal insulation composite systems (ETICS), self-leveling compounds and fillers, plasters and repair mortars,” says Andreas Collignon, head of Application Technology Construction Polymers at WACKER POLYMERS.

For ETICS, up to four percent VINNAPAS® in the mortar is enough to form a stable bond between the insulation board and substrate, for example. VINNAPAS® polymers provide an ideal and long-term solution, particularly for fixing difficult-to-bond materials to critical substrates.

Polymeric binders also revolutionized tile-laying by introducing the so-called thin-bed technique, in which the traditional cement mortar is replaced by a formulated tile adhesive that is spread quickly and easily over a large area. The tiles are then positioned and slid into place, creating a uniform adhesive bed that is just millimeters thick. Less material is consumed and tiles can be laid much faster. Possible applications are to be found all over a building, from tiled flooring through to roof insulation.

New dispersible polymer powders for tile adhesives

WACKER has developed a novel dispersible polymer powder for modifying cementitious and gypsum-based dry-mix mortars especially for tile adhesives. Based on a novel vinyl-chloride vinyl acetate-ethylene terpolymer, VINNAPAS® 8620 E ensures that tile adhesives adhere excellently to a broad range of different surfaces, including difficult ones such as fired tiles with high densities and natural-stone products – even after heat, water or freeze/thaw cycles. The dispersible polymer powder was specifically developed for the formulation of sophisticated tile adhesives of categories C2E or C2ES1 and C2ES2 as per EN 12004 that feature an extended open time and high flexibility. It thus offers users additional formulation reliability. With VINNAPAS® 8620 E in the formulation, it is thus even possible to reliably bond modern large-format or very thin tiles, as well as porcelain or natural-stone materials. Alongside exceptional product and processing properties, VINNAPAS® 8620 E also exhibits good environmental compatibility, because the product is free of plasticizing additives and thus makes it possible to formulate low-emission tile adhesives.

Benefits of the Modification

“Thin-bed systems, which include tile adhesives, afford polymer-modified dry-mix mortars the chance to show what they can do,” says Ole Mecker, head of the Eastern Europe, Middle East & Africa business team at WACKER in Burghausen. The polymers impart flexibility to the rather brittle mortar, enabling the hardened construction material to accommodate slight stresses between the substrate and tile. That boosts the level of adhesion between tile, mortar and substrate.

Polymer-modified dry-mix mortars also exhibit better water retention. This makes them easier to process and they do not dry out so quickly. The polymer in the hardened construction material improves the mechanical properties – the material can thus withstand load better and is more abrasion resistant. Finally, VINNAPAS® dispersible polymer powders also save on material: whereas conventional tiling requires more than ten kilograms of adhesive per square meter, the thin-bed technique requires only approx. one-third as much polymer-modified dry-mix mortar for the same area. It was these compelling advantages which persuaded the construction industry to adopt the very first dispersible powders, launched by WACKER in the 1960s, and they are winning over even more customers today.

Global demand for WACKER dispersible polymer powders rose by six percent in 2013 alone. Consequently, WACKER has been successively expanding capacity at all three of its production sites in Europe, Asia and the USA. In 2013, bottlenecks at Calvert City (Kentucky) were eliminated; the Nanjing plant in China is scheduled to double its current annual capacity by the end of 2014 and by the first half of 2015, there will be a new spray dryer that can produce some 50,000 tons of additional dispersible polymer powder in Burghausen.