Materials Science

WACKER to unveil new, flexible binder for protecting mineral flooring

At the European Coatings Show 2019 (ECS 2019), Munich-based chemical group WACKER will be presenting SILRES BS 6921, a new silane-based binder. This product has been specifically developed for blending with SILRES BS 6920, which itself is a binder for the production of hard-wearing, stain-resistant anti-soiling coatings for concrete floors. Addition of SILRES® BS 6921 yields products which are much more flexible. Such coatings are eminently suitable for treating epoxy or polyurethane floors in need of repair. By virtue of their strong bonding properties, the formulations also lend themselves to the production of stone carpets and pervious systems. In those applications, the binder provides a flexible bond between the stones. The European Coatings Show will be held in Nuremberg, Germany, from March 19 to 21, 2019.

Like SILRES BS 6920, which was unveiled for the first time at the ECS 2017, SILRES BS 6921 is based on alpha-silane technology. However, the new product is much softer than its predecessor. The low-viscosity alpha-silane-terminated polyether cures rapidly upon contact with atmospheric moisture to yield a comparatively soft, flexible coating that affords outstanding protection against soiling and staining.

The main purpose of the new binder is to flexibilize the chemically related SILRES BS 6920, which is already being used for transparent, extremely hard-wearing concrete floors, but which is too brittle for use with flexible substrates. Its hardness creates a risk of cracking, should the floor experience mechanical stress or deform in response to large temperature fluctuations.

With SILRES BS 6921, it is now possible to formulate much more flexible coatings that can also withstand thermal expansion and mechanical deformation. Tests show that 20 to 30 percent SILRES® BS 6921 is enough to adapt the binder to the properties of the intended substrate. Such formulations bond very strongly not only to cementitious floors, but also to epoxy and polyurethane substrates.

The bond is in fact so strong that the formulations are suitable for manufacturing repair sets for damaged epoxy or polyurethane flooring, pervious systems and stone carpets. SILRES® BS 6921 is a crystal-clear formulation and remains transparent after curing. Yellowing induced by exposure to the sun or other light sources is reliably prevented by the addition of light stabilizers.

The binder combination is formulated to yield one-part end products which can be applied with a mop, roller or spray gun. The coating is generally applied in two thin layers, at an average rate of 100 grams per square meter. The first coat strengthens the floor. The second produces a more homogeneous finish that increases stain, scratch and scrub resistance and makes the floor polishable.

Coatings based on blends of SILRES BS 6921 and SILRES BS 6920 are equally at home in multistory car parks, automotive workshops, railway station buildings and logistics centers as they are in display and sales rooms, bistros, halls where events and exhibitions are held, and museums and private dwellings. The treated floor is easier to maintain and stain resistant as a result of the treatment. Abraded material, dirt and liquid spills can be removed with ease.

New at ECS 2019: the WACKER Forum
WACKER will be devoting a total of 240 square meters of floor space to solutions for paints, coatings, construction and adhesives applications at the 2019 European Coatings Show. More than 70 experts will be on hand at Booth 1-510 in Hall 1 to discuss the products and their applications with interested parties. Making a new appearance this year will be the WACKER Forum, right beside the main booth. Here, 30-minute presentations aimed at an international specialist audience will be held on technology, trends and innovations under the motto “Let’s talk about…” More information about the program of presentations at the WACKER Forum can be found at